bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cathodoluminescence Microcharacterization of the Irradiation Sensitive Defect Structure of Amorphous Silicon Dioxide
Authors: Stevens Kalceff MA , Phillips MR , Moon AR 
Published: July 2020

Abstract
Cathodoluminescence (CL) Microscopy (imaging) and Spectroscopy in a Scanning Electron Microscope enables high spatial resolution, high sensitivity detection of defect centers in materials. Cathodoluminescence microanalysis has been used to investigate the irradiation sensitive defect structure of Types I, II, III and IV amorphous silicon dioxide SiO2 (quartz and silica glasses). The CL experiments were performed in a JEOL JSM 35C SEM equipped with Oxford Instruments liquid N and liquid He cryogenic stages, and an Oxford Instruments MonoCL cathodoluminescence imaging and spectral analysis system. The observed CL emissions, were excited with a stationary electron beam at normal incidence and corrected for total instrument response. The corrected CL spectra were fitted with a multiparameter Gaussian function using a non linear least squares curve fitting algorithm and were identified with particular defect structures. The CL emission from high quality pure amorphous silica and quartz glasses is dominated by intrinsic processes (associated with the host lattice). See Table 1.
Polymorphic Transition in Biogenic Calcium Carbonate: Nacre/Prismatic Interface in Abalone Shell
Authors: Freeh Daniel M , Sarikaya Mehmet 
Published: July 2020

Abstract
The research in biological hard tissues offers lessons for biomimetic (structure and processing) strategies, such as for the synthesis of hierarchical architectures tailored for specific engineering applications. These biocomposites, i.e., biogenic materials in which the major phase is an inorganic component associated with macromolecules (proteins and polysaccharides), include bones, dentin, sea-urchin skeletal units, bacterial and algal particles and molluscan shells. Here, a summary is given from a recent TEM study of the interfacial region of nacreous and prismatic sections of red abalone shell to understand the morphological and crystallographic correlations across this transition region.
Many mollusk species have shells made of CaCO3 in various architectures that have evolved under different ecological conditions to produce structures that best protect the organism. The shells of many species contain both aragonite (orthorhombic, Pmnc) and calcite (Rhombohedral, R3m). In red abalone (Haliotis rufescens), the outer section, prismatic (P), is composed of columnar crystallites of calcite (1-5 μm base, 5-10 μm height), and the inner section, nacre (N), is composed of pseudo-hexagonal platelets of aragonite (side 2-5 μm), stacked as 0.25 μm layers, separated by a few nm-thick organic layer (Fig. 1).
Optical Coherence Microscopy: A New Technique for High-Resolution, Non-Invasive Imaging in Bulk Biological Tissues
Authors: Izatt Joseph A , Kulkarni Manish , Wang Hsing-Wen , Sivak Michael V 
Published: July 2020

Abstract
Optical coherence microscopy (OCM) is a novel technique complementary to optical coherence tomography (OCT) which combines low-coherence interferometry with confocal microscopy to achieve micron-scale resolution imaging in highly scattering media. OCM may be implemented using a single-mode fiber-optic low-coherence interferometer (See Fig. 1). A high numerical aperture objective is used to focus sample-arm light into the specimen, and the reference arm length of the interferometer is adjusted to match the sample arm focal plane optical depth. The sample arm of the interferometer comprises a scanning confocal microscope, in which either the sample or the probe beam is laterally scanned in a raster pattern, and the optical fiber acts as a single-mode confocal aperture for combined light illumination and collection. The reference arm length of the interferometer establishes the depth position of an interferometric “coherence gate” in the sample, from which backscattered light is preferentially collected. Initial studies of OCM in scattering phantoms have demonstrated that this technique provides increased optical sectioning depth compared to confocal microscopy alone.
Sub-100nm Axial Resolution in 3D Widefield Optical Microscopy Using Two Opposing Objective Lenses
Authors: Gustafsson Mats GL , Agard David A , Sedat John W 
Published: July 2020

Abstract
It has been understood since the days of Ernst Abbe that an optical microscope can reach higher resolution the wider the set of angles from which it can observe the specimen — this angular range, of course, is what is indicated by the Numerical Aperture (NA) of the objective lens. Over more than a century of objective lens development, this light collecting angle has been increased closer and closer to the full 180° angle available above a microscope slide. There is, however, a second, equally large and easily accessible set of observation angles available on the other side of the specimen slide, and a standard microscope makes no use whatsoever of light emitted in these directions. One might then ask whether there is not a substantial resolution advantage to be had by devising a microscope that does make use of this "back side" light. The answer, in fact, is yes.
Sub-Millisecond Time Resolved Imaging of Voltage Changes in Excitable Cells and Tissues Using Multiple Site Optical Recording of Transmembrane Voltage (Msortv) and Molecular Probes
Authors: Salzberg BM , Obaid AL 
Published: July 2020

Abstract
Molecular indicators of membrane potential may be used to obtain sub-millisecond time resolved images of transient changes in membrane voltage in a variety of biological systems. These probes are small amphipathic molecules having molecular weights of 400-500, and dimensions on the order of 10 Angstroms, which bind to, but do not cross cell membranes, and change either their absorbance or fluorescence in response to membrane voltage. These extrinsic optical signals depend linearly upon membrane potential, and the best of the dyes respond to a step change in voltage in less than 1.5 μsec at room temperature. The salient properties of fast potentiometric probes will be discussed, and the fidelity of optical recordings to transmembrane voltage changes will be considered.
Since voltage changes in excitable cells take place on a time scale that is determined by the kinetics of conformational changes in membrane proteins, and by membrane electrical time constants, these changes tend to be very rapid, and resolving them requires imaging systems that are frequently orders of magnitude faster than usual video rates.
Near-Field Optical Spectroscopy: Enhancing the Light Budget
Authors: Paesler MA , Hallen HD , Yakobson BI , Jahncke CJ , Boykin PO , Meixner A 
Published: July 2020

Abstract
The near-field scanning optical microscope, or NSOM, provides spectroscopists with resolution beneath the diffraction limit. In the NSOM, an optical aperture smaller than the wavelength λ of the probe radiation is scanned in the near-field of a sample. Pixels are serially gathered and then constituted as a computer-generated image. Spectroscopic NSOM investigations demonstrating sub-λ, resolution include studies of photoluminescence, Raman spectroscopy, and single molecule fluorescence. Results of nano-Raman spectroscopy on semiconducting Rb-doped KTP are shown in figure 1. Figure la is a topographic image of the sample showing a square Rb-doped region in an otherwise undoped sample. Figure lc is a NSOM region of the corner of the doped region, and figure lb is an image of the same region taken within a Raman line. While these data do provide sub-λ spectroscopic resolution and other interesting features, the weak signal provided by current NSOM technologies and the low quantum efficiency of the Raman effect necessitated development of a very low-drift microscope and inconveniently long collection times.
Submicron Optical Spectroscopic Surface Characterisation Using Near-Field Probes.
Authors: Webster S , Kerhsaw K , Batchelder DN , Quirke P , Lidzey D , Bradley DDC , Smith DA 
Published: July 2020

Abstract
The development of scanning near-field optical microscopy has provided a submicron optical tool which has important applications in both fundamental studies and in device fabrication and analysis. The strength of the technique lies not only in its resolution of approximately 50nm, which is an order of magnitude improvement on diffractive optical techniques, but also in its ability to allow highly developed optical spectroscopies to be used for chemical analysis at this resolution. We have particular interest in the application of near-field probes to high spatial resolution laser spectroscopy in a range of organic, biological and inorganic systems. In this paper we shall describe the development of instrumentation for luminescence, Raman and time resolved spectroscopy in air and under fluids and will present the results of studies of phase separated polymer mixtures, organic crystals and semiconductor materials.
The current scanning near-field optical microscope is based around a tapered optical fibre, at the end of which a submicron aperture has been defined by a metal coating.
High Spatial and High Spectral Resolution FTIR Spectroscopic Imaging of Biological Materials
Authors: Lewis EN , Kidder LH , Levin IW 
Published: July 2020

Abstract
Infrared spectroscopy has been used to probe a variety of biological systems including for example, the determination of diseased states and the investigation of foreign inclusions in biologicals. The technique generates qualitative and quantitative information on the structure and dynamics of samples, including lipids, proteins, and non-biological constituents. The coupling of imaging modalities with spectroscopic techniques adds a new dimension to sample analysis in both the spectroscopic and spatial domains. Using a spectroscopic imaging system that incorporates a step-scan interferometer, microscope, and infrared sensitive arrays, we have investigated a variety of biological samples. This seamless combination of spectroscopy for molecular analysis with the power of visualization generates chemically specific images while simultaneously obtaining high resolution spectra for each detector pixel. The spatial resolution of the images approaches the diffraction limit for mid-infrared wavelengths, while the spectral resolution is determined by the interferometer and can be 4 cm−1 or higher.
Uv Raman Microscopy: Spectral and Spatial Selectivity and Even High Sensitivity
Authors: Munro Calum , Pajcini Vasil , Asher Sanford A 
Published: July 2020

Abstract
We have constructed a new UV Raman microspectrometer designed around an Olympus microscope, a single spectrograph and an intensified CCD detector (Fig. 1). We utilize CW excitation from either an intracavity frequency doubled Ar+ laser (257, 244, 229 nm) or a Kr+ laser (206 nm). We optimized the throughput by utilizing specially prepared dielectric coated Rayleigh rejection filters.
In one application we used this instrument to speciate and determine the spatial distribution of non diamond carbon species in CVD diamond samples (Fig. 2). We find that these non diamond carbon species are localized in the interstitial areas between diamond crystals.
In another application we demonstrated the utility of UV Raman microspectroscopy for the rapid, incisive and non-destructive characterization of meteorites and interplanetary dust particles (IDP). In addition to probing the structure and distribution of predominant mineral matrices of these materials, UV excitation enables us to the characterize the small but significant carbonaceous components included within these samples.
Optical Non-Linearities in Infrared Mircospectroscopy: A Preliminary Study into the Effects of Sample Size and Shape on Photometric Accuracy
Authors: Stewart SA , Sommer AJ 
Published: July 2020

Abstract
Several years ago this laboratory reported on the effects of stray light in an infrared microscope and its consequences on the spatial resolution achievable in a typical line scan or mapping experiment of a polymer film. In this study it was demonstrated that unless the size of the sampled area was greater than twice the wavelength of light employed for the analysis, a significant amount of stray light from near neighbors was contained in the sampled areas. Further, this generalization is only valid for sample sizes above the diffraction limit. The results of this study are summarized in Table. The ratio of the sampled area to that of the aperture size (corresponding to expected sample size) can be thought of as a degradation factor in spatial resolution. In this earlier study the sample geometry was chosen to minimize stray light effects arising from the sample size and shape.
Imaging Spectroscopy Using Fiber Optics
Authors: Michael Angel S , Trey Skinner H , Marquardt Brian J 
Published: July 2020

Abstract
Optical fiber probes are routinely used with optical spectrometers to allow measurements to be made on remotely located samples. In most of these systems, however, the optical fibers are used as non-imaging “light pipes” for the transmission of laser light, and luminescence or Raman signals to and from the sample. Thus, while these systems are suitable for remote spectroscopy, they are limited to single-point measurements. In a recent paper, we showed that a small-diameter (i.e., 350 μm) coherent optical fiber bundle can be combined with an AOTF-based imaging spectrometer for fluorescence and Raman spectral micro-imaging with increased flexibility in terms of sample positioning and in-situ capabilities. The previous paper described the operation of the fiber-optic microimaging probe and AOTF imaging system and showed preliminary Raman and fluorescence images for model compounds with 4 μm resolution. We have extended this work to include a discussion of the lateral and vertical spatial resolution of the fiber-optic microprobe in a non-contact proximity-focused configuration.
Exploratory Investigation of Synthetic Zeolites by Near-Infrared Fourier-Transform Raman Microspectroscopy
Authors: Etz Edgar S 
Published: July 2020

Abstract
Zeolites are complex, three-dimensional, hydrated crystalline aluminosilicates that have porous structures with channels or cages of various dimensions. In the simplest way they can be represented by (Na2,K,Ca,Ba) [(Al,Si)O2]nxH2O. They may be either of natural or synthetic origin. As high-surface-area materials, they take on great technological importance, foremost in surface science and catalysis. The structure of the zeolite is critical to its function. Structure information is commonly obtained by x-ray and neutron diffraction, NMR, IR, and Raman spectroscopy techniques. Synthetic zeolites are produced in enormous quantities worldwide and are key to critical technologies. Yet, no real zeolite standards exit that are defined and certified. NIST, with input from industry and academia, has begun a measurement program to certify various physico-chemical properties for a suite of synthetic zeolite powder standard reference materials (SRMs) and research materials (RMs). These proposed "standard" zeolite materials span a range of pore sizes, SiO2/Al2O3 ratios, ring sizes, structural building units, and cage sizes.
Experimental Validation for Infrared Microspectroscopy (IMS)
Authors: Reffner John A , Hornlein Robert W , Hellgeth John W 
Published: July 2020

Abstract
In today’s laboratory environment, it is important that the performance of analytical instruments be tested and validated. In the past, the testing of infrared micro- spectrometers was based solely upon measuring a signal-to-noise (SNR) ratio of the 100% line. This test is insufficient. It is important to test how well the sample area is defined. In all current commercial infrared spectrometer systems, remote image plane masks are used to define specific areas for infrared spectral analysis. A special test specimen has been developed to evaluate the accuracy of the mask’s ability to define the sample area.
IMS resolution test plates were constructed by photolithographic reproduction of a series geometrically shaped thin polymer films on both infrared transparent windows and gold mirrors. First the surface of the plate is coated with a thin, uniform layer of a photoresist polymer. Then this surface is printed with geometrical patterns such as bands, discs and squares.
Auger To The Max: Can We Color The Atoms In Our Stem Images?
Authors: Hembree Gary G 
Published: July 2020

Abstract
A probable future development in materials science is the selective manipulation of structure on an atom by atom basis. Along with the ability to manipulate atoms we will need to be able to tell if the correct ordering has been achieved. Thus the ultimate goal of spectroscopic imaging will be to create a species-labeled two or three dimensional map of the atom positions in the sample. In this paper we will show how far we have progressed towards this goal with Auger electron spectroscopy (AES), how much further we have to go and what the prospects are for overcoming the known obstacles.
AES is inherently surface-sensitive because low energy electrons have very small inelastic mean free paths. This scattering mechanism insures that only those electrons created within a few atomic diameters of the sample surface facing the detector will contribute significantly to the measured signal.
Secondary Ion Mass Spectrometry For The Year 2000 and Beyond: Are There Any Showstoppers?
Authors: Magee Charles W 
Published: July 2020

Abstract
The National Technology Roadmap of Semiconductors (NTRS) shows that future semiconductor processing will require the formation of junctions less than 30nm deep with gate lengths approaching, and becoming less than, 0.lum. Techniques must be available to measure these in-depth, as well as spatial, distributions.
Secondary ion mass spectrometry (SIMS) has long been the technique of choice for measuring dopant profiles in semiconductors. The depth of the junctions formed has, up top now, always been sufficiently deep into the semiconductor that the effects of the analysis on the measured profile (i.e. atomic mixing) could be ignored for the most part. In addition, gate lengths have been sufficiently large that diffusion of LDD implants under the gate have not contributed significantly to short-channel effects. However, the relentless decrease in the required junction depths and gate lengths may mean that the situation may change in the near future.
Interpretation of Changes in Peak Shape and Position of the Oxygen Kα Characteristic X-Ray Line
Authors: Harrowfield I R , MacRae C M , Rajakumar V , Wilson N C 
Published: July 2020

Abstract
Changes in shape and position of long-wavelength X-ray lines measured by wavelength dispersive spectrometry (WDS) reflect changes in the density of bonding states of the emitting atom. However, some features of soft X-ray spectra are not due to bonding. For example, small peaks on the shorter-wavelength side of a characteristic peak probably arise from double ionization, absorption effects must be considered and there may be artefacts from the diffracting crystal itself. Nonetheless, when there are dramatic shape changes, spectrometry of soft X-rays can usefully augment microanalysis particularly in the study of tiny particulates which may be difficult to prepare for transmission microscopy.5 Two examples of spectrometry of O Kα follow.
Oxidation of very fine TiB2 particulates is a problem in the ceramics industry. The backscattered electron (BSE) micrograph in fig. 1 shows a particle section with a central core of TiB2 and a darker, oxidised rim analysing roughly like a borate, interspersed with brighter regions, probably TiO2.
Feasibility of Be Analysis For Geologic Materials Using Epma
Authors: Evensen Joseph , Meeker Gregory P 
Published: July 2020

Abstract
Microanalytical techniques for the analysis of beryllium using the electron probe have been evaluated for Be metal, Be-rich silicate minerals, and three Be-rich synthetic silicate glasses. Despite difficulties typical of ultra-light element analysis in geologic materials, quantitative data for Be may be obtainable through careful analytical measurements, determination of optimal operating conditions, and consideration of parameters such as sample orientation and beam-induced migration.
Analyses for Be were obtained using a layered synthetic microstructure “crystal” (Mo/B4C) on the JEOL 8900 electron microprobe at the USGS, Denver, Colorado. The optimum accelerating voltage for Be detection was determined to be 8kV (Fig.l). Beryllium analyses in glass and mineral phases were successful using a beam current of 30nA and a 50 μm beam diameter. Due to low count rates, peak counting times of 10 minutes (beryl) and 30 minutes (glass) were required in order to achieve reasonable counting statistics and detection limits.
Quality Assurance of Energy Dispersive Spectrometry Systems
Authors: Steel E B , Marinenko R B , Myklebust R L 
Published: July 2020

Abstract
Monitoring the performance capabilities of energy dispersive X-ray spectrometers (EDS) and related x-ray analysis electronics and software is important for determining and improving the reliability, sensitivity, and accuracy of the x-ray analysis system. In addition, there is a growing popularity of quality systems through laboratory accreditation and ISO 9000 related programs that require set quality control procedures for analytical instrumentation. Having similar standard procedures amongst labs would allow direct intercomparison of results. This intercomparison would help labs and manufacturers determine what are normal versus abnormal results and lead to higher quality instruments and analyses. We have been developing a standard operating procedure for the characterization of EDS x-ray analysis systems on electron beam instruments.
We are designing the procedure to maximize the efficiency of each quality control (QC) measurement so that we spend as little time monitoring the analysis system as is possible. We first chose useful QC specimens and then designed data collection methods.
First X-Ray Microprobe and Microspectroscopy Results From The Gsecars Sector At The Advanced Photon Source
Authors: Rivers Mark L , Sutton Stephen R , Eng Peter , Newville Matthew 
Published: July 2020

Abstract
The Advanced Photon Source (APS) at Argonne National Laboratory is a third-generation synchrotron x-ray source, optimized for producing x-rays from undulators. Such undulator sources provide extremely bright, quasi-monochromatic radiation which is ideal for an x-ray microprobe. Such microprobes can be used for trace element quantification with x-ray fluorescence, or for chemical state determination with x-ray absorption spectroscopy. The GeoSoilEnviroCARS (GSECARS) sector at the APS is building an x-ray microprobe for research in earth, planetary, soil and environmental sciences.
The GSECARS undulator source is a standard APS Undulator “A” which is a 3.3 cm period device with 72 periods. The energies of the undulator peaks can be varied by adjusting the gap, and hence the magnetic field of the undulator. The energy of the first harmonic can be varied in this way from approximately 3.1 keV to 14 keV. A measured undulator spectrum is shown in Figure 1.