bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Spectroscopic Imaging (ESI) of Viral DNA- and RNA-Distribution Using a New Method of Background Subtraction
Authors: C.Crucifix  , Witz J , Schultz P , Pawlita M , Trendelenburg M F , Probst W , Haking A , Troester H 
Published: July 2020

Abstract
Our investigations are aimed to exploit the potential of Electron Spectroscopic Imaging (ESI) using an LEO EM 912 Omega to perform element detection without any background signal included in the net elemental signal. In a first series of experiments we designed an approach for phosphorus (P) detection by using an internal mass-thickness marker in the shape of a carbon ramp combined with the two-window difference method in order to eliminate mass thickness signals [1]. However, pure carbon seems not to be ideal because this approach does not take into account the more complex elemental composition of biological samples ( H, N, O, P and S) compared to pure carbon within the reference. Consequently, we had to find an easy-to-handle and reproducible technique to include a combined Compositional- and Massthickness Marker (C:M-Marker) in the specimen under investigation. Fig. 1A shows the result of such an experiment. Turnip Yellow Mosaic Viruses (TYMV; bright particles) were layered on top of a carbon foil followed by a wash with distilled water and air drying. To form an internal C-M-Marker a 1%-solution of Bovine Serum Albumin (BSA), dialysed against H2O, was sprayed on the opposite side of the same sample resulting in localized aggregations of BSA with different thicknesses (bright region “M, Fig. 1A). It serves the same purpose like the carbon ramp [1]: a pre-edge image (115 eV) and a second one (150 eV, core edge image) are taken to calculate the intensity (I) background function I150 (I115) using only values from the C-M-Marker region. Then the P-map image can be calculated by subtracting the extrapolated contribution of the protein part from the core-edge image. For the case presented in Fig. 1A this procedure resulted in Fig. 1B where the TYMV intensity signals can still be seen whereas the BSA ramp vanished.
Microtextural Characterization and Orientational Mapping of Polycrystalline Thin Films Using TEM Dark Field Imaging Through an Annular Objective Aperture
Authors: Williamson M , Hull R , Dunn D , Greene J , Kodambaka S 
Published: July 2020

Abstract
Several methods have been applied to the texture characterization of polycrystalline films, including X-ray diffraction and several SEM and TEM techniques. Few of these techniques combine high spatial resolution with the ability to characterize large sample areas in a short time. We have fabricated annular objective apertures for the TEM, extending earlier work of Heinemann and Poppa, to characterize the orientation and size of grains within polycrystalline thin films. This procedure is similar to conical dark field imaging which has been shown to provide microtextural information over large areas
Apertures were fabricated using a FEI FIB-200 focused ion beam (FIB) workstation. Bitmap templates of apertures were created using Adobe Illustrator™ and converted to stream files. These stream files were then used to controllably cut annular apertures into an existing platinum JEOL aperture strip with a 30 keV Ga+ FIB. The apertures were then placed in the objective aperture drive of a JEOL 2000FX transmission electron microscope and TiN thin films were imaged in bright- and dark-field imaging modes.
An Investigation of Plastic Strain in Copper by Automated-EBSP
Authors: Sutliff J A 
Published: July 2020

Abstract
This work describes the investigation of plastic strain in tensile deformed polycrystalline copper using the automated Electron BackScatter Pattern (EBSP) technique of electron diffraction in the Scanning Electron Microscope (SEM). A strong correlation was found between the known accumulated plastic strain in OFHC copper tensile specimens and quantitative measurements of intra-grain misorientation obtained from an analysis of automated-EBSP data.
Previous works on strain measurement using EBSP analysis have focused on the influence of dislocation density on the intensity profiles of diffraction bands. It is known that for some materials, like copper, deformation strain produces highly organized dislocation structures and thus the dislocation density is very inhomogeneous on the sub-micron scale probed by EBSP. This suggests that plastic strain analysis using the EBSP dislocation density analysis route will be difficult to reliably implement in these materials.
A Study on the Characteristics of the Boundaries in Bainitic Low Alloy Steels Using Electron Back-Scatter Diffraction (EBSD) Technique
Authors: Oh Yong-Jun , Kim Min-Chul , Hong Jun Hwa 
Published: July 2020

Abstract
Bainitic low alloy steel has a complex microstructure exhibiting several types of boundaries. The boundaries in bainitic steel, although certain boundaries are absent with respect to the alloy composition and the manufacturing process, could be typically divided into 4 types; dislocation cell boundary, lath boundary, packet boundary, and prior austenite grain boundary, in increasing order of size. The size and distribution of the respective boundaries are an important factor which controls the mechanical properties of the steels, including brittle fracture. In the present research, the characteristics of the boundaries in the bainitic low alloy steels were investigated in view of misorientation between grains enclosed by the respective boundaries.
The alloys investigated were Mn-Mo-Ni low alloy forging steels having chemical compositions shown in TABLE 1. Steel-A was manufactured by the Vacuum Carbon Deoxidation(VCD) process. For the finer prior austenite grain size, Steel-B was produced by the aluminium addition and the silicon killing process. Before EBSD analysis, the microstructures of the alloys were observed using SEM and TEM. EBSD measurements were obtained using a Link OPAL system(Oxford) linked to a JEOL JSM 6300 SEM operating at 15KeV with the sample tilted at 70°.
Epitaxial Orientation Determination of Nanosized Particles by EBSD
Authors: Cosandey F , Zhang L , Madey T E 
Published: July 2020

Abstract
Metals on oxide systems are important in applications such as catalysts and gas sensors. The Au/ TiO2 system is of particular interest because of its high activity for low temperature oxidation of CO and its good sensitivity as CO gas sensor. In this study, we are reporting results on the effect of substrate temperature on epitaxial orientation relationship of Au particles formed on TiO2 (110).
Two Au films were grown on TiO2 (110) substrates by vapor deposition in a UHV chamber. The first one was produced by evaporation of a 12nm thick Au film at 300K, followed by annealing at 775K for 1 hour. The second one was produced by direct deposition of a 12nm film on TiO2 substrate maintained at 775K. The samples were transferred in air to the Field Emission Scanning Electron microscope (LEO 982 Gemini) for imaging and diffraction..Electron Backscatter Diffraction (EBSD) patterns were taken from individual Au particles using the Opal system (Oxford Instruments). With this system, a spatial resolution of the order of 80 nm has been achieve for Au.
A typical HRSEM image of the Au film deposited a 300K and annealed at 775K is shown in Fig. 1 revealing a discontinuous Au film consisting of discrete Au particles in the range from 20 to 150 nm.
Review of Electron-Gas Interactions in the Environmental SEM
Authors: Thiel BL 
Published: July 2020

Abstract
Understanding the various interactions between electrons and the specimen chamber gas is essential to using environmental and low-vacuum SEM’s to their full potential. The problem can be divided into two main topics: distortion of the primary beam on its way to the sample surface, and amplification of the various electron signals leaving the sample. These issues are important for all low-vacuum SEM’s, regardless of the system design or signal detection method. All instruments must contend with scattering of the primary beam in the gas, and the subsequent effects on resolution, background signals,.and x-ray generation. Similarly, while some instrument designs rely more heavily than others on signal amplification in the gas, all benefit from the concomitant charge neutralisation.
As the electron probe travels through the gas on its way to the specimen, elastic collisions occur with molecules in the gas.[1] Fortunately, for gas pressures of a few torr, the mean free path is on the order of tens of millimetres, and the vast majority of electrons reach the specimen unscattered.
Contrast formation mechanisms in the environmental scanning electron microscope
Authors: Toth M , Phillips MR 
Published: July 2020

Abstract
Uncoated, non-conductive samples can be imaged and analyzed in the environmental scanning electron microscope (ESEM) due to effective charge neutralization at the sample surface by ionized gas molecules. Under some gas pressure and electron dose conditions, ESEM images of uncoated, poorly conductive samples often contain contrast not present in secondary or backscattered electron images of the (coated) samples obtained in conventional SEMs. It has been proposed that the contrast is related to charge trapping at defects and impurities. It has also been suggested that UV cathodoluminescence (CL) may contribute to contrast in the ESEM. In this paper, we present experimental evidence of contrast formation in the ESEM due to charge trapping in Dy doped zircon, electron trapping at oxygen vacancies in sapphire and the absence of signal generation by 360nm UV CL.
The specimens used in this study were (i) cross-sectioned Titanium in-diffusion doped sapphire single crystal, (ii) Dy doped synthetic Zircon7 and (iii) 43 μm epitaxial GaN grown on c-pane sapphire by hydride vapor phase epitaxy.
Secondary Electron Yield Curve for Liquid Water
Authors: Thiel BL , Stokes DJ , Phifer D 
Published: July 2020

Abstract
We have measured the secondary electron yield curve for liquid water using an Environmental SEM. The secondary electron emission coefficient, measured as a function of incident electron energy, is important for interpreting contrast in hydrated biological and inorganic specimens. This information is even more critical for water than other materials, as it is a factor of prime importance in understanding radiation damage in biological tissues.[1]
These measurements were taken using a Philips XL-30 field emission,ESEM, and repeated on an Electroscan E3 ESEM, equipped with a CeB6 filament. A specially designed Faraday cup was fashioned from brass and fitted with a removable graphite cup having an inset for a platinum aperture. This assembly was placed into an electrically floating Peltier cooling stage, and connected to a KE Instruments probe current meter.
ESEM Imaging of P-N Junctions Using a Gaseous Secondary Electron Detector
Authors: Phillips MR , Toth M , Drouin D 
Published: July 2020

Abstract
Contrast in secondary electron images of p-n junctions has been observed using a FESEM operating at 1kV. This contrast has been attributed to energy band-bending effects and dopant level variations. In this paper, we report that contrast from the depletion layer of a p-n junction can be obtained in an ESEM using a gaseous secondary electron detector (GSED). The contrast is caused by a signal induced in the GSED by charging and discharging of the device.
A 1N4002 p+pn silicon power diode was cross-sectioned along the lead axis to expose the Ag ohmic contacts and the semiconductor device. The section was mechanically polished to an optical finish using diamond abrasives and mounted in a holder which allowed electrical connection to both the p and n sides of the diode. Imaging experiments were performed in a Philips Electroscan XL30 ESEM and a JEOL 6300F below-lens FESEM. Current images were obtained with a GW Electronics 103 specimen current amplifier.
A Novel Technique for Probe Intensity Profile Characterisation in the Environmental Scanning Electron Microscope
Authors: Phillips MR , Toth M , Drouin D 
Published: July 2020

Abstract
The environmental scanning electron microscope (ESEM) allows imaging and analysis in a gaseous environment at pressures up to 20 torr. Gas phase scattering of primary electrons leads to a loss of useable probe current and produces an electron skirt around the beam that can degrade the spatial resolution in microanalytical studies. Progress in ESEM microanalysis requires accurate modeling and measurement of the beam intensity profile. Previously, x-ray techniques and beam sensitive materials have been used to measure the extent of the skirt. These investigations have yielded inconsistent skirt distances possibly due to dose dependence of the measurement techniques. We present a new, high gain method to measure the useable probe current and skirt profile using the electron beam induced current (EBIC) from a P-N junction.
The interface of an N- and a P-type semiconductor contains an electrostatic donor-acceptor dipole (“depletion layer”) created by an electron-hole recombination energy minimization mechanism.
Accuracy of Spatial Measurements at Elevated Temperatures in an Environmental Scanning Electron Microscope
Authors: Schalek Richard L , Drza Lawrence T 
Published: July 2020

Abstract
One of the unique abilities of the environmental scanning electron microscope is that it permits realtime dynamic observations of materials under controlled temperature/atmosphere conditions [1]. The need for accurate and precise measurements of dimensional changes at elevated temperatures arise in many material areas including determining the longitudinal and transverse coefficient of thermal expansion of fibers, sintering studies, hydration and dehydration of absorbent polymers, and strain measurement of materials under an applied load. The purpose of this research is to evaluate the capabilities of an ElectroScan 2020 environmental scanning electron microscope (ESEM™) in performing precise in situ spatial measurements at elevated temperatures. Identification and proposed solution and/or compensation of imaging difficulties such as specimen drift, sample stability, and thermal strain of a reference grid are addressed.
In general, the accuracy of spatial measurements in a scanning electron microscope (SEM) depends on several factors including calibration of the scanned area, the effects of lens hysteresis and reproducibility in the working distance and column alignment.
In Situ TEM Study of DNA/Gold Nanoparticles in Liquid Environment
Authors: Chiou W-A , Mucic R C , Ishikawa A , Konishi H , Fukushima K , Mirkin C A 
Published: July 2020

Abstract
In recent years the assembly of nanometer sized building blocks into two- and three-dimentional structures and functional materials has been an extremely active area of scientific research. A new class of materials, the DNA/nanoparticle hybrid materials and assemblies, which might have useful electrical, optical and structural properties, have been developed at Northwestern University. While characterizing particle morphology (size and shape) by subjecting it to the high vacuum environment in an electron microscope, the structure may have changed drastically from its natural state. The study of morphology of these DNA/Au nanoparticles in the liquid state was thus undertaken to further our understanding of the dynamics of the nanoparticles in a specific environment. This paper presents an in-situ observation of DNA/Au nanoparticle assembles in liquid media using environmental TEM.
Experiments were carried out with citrate-stabilized colloidal Au particles averaging 8 and 31 nm in diameter. Colloidal Au nanoparticles were obtained from a commercial source. 8 nm particles were modified with propylthiol-capped oligonucleotide, 3’HS(CH2)3-O(O)P(O)O-ATG-CTC-AAC-TCT, 1,whereas the 31 nm particles were modified with hexlylthiol-capped oligonucleotide, 3’TAG-GAC-TTA-CGC-O(O)P(O )O-(CH2)6SH, 2.
TECNAI: the Concept for Modern TEM/STEM Analytical Systems
Authors: Nadarzinski K 
Published: July 2020

Abstract
Decreasing dimensions and the necessity to understand the structure and composition of materials or devices on a nanometer scale has led to new developments in TEM. Previously EDX analysis had been established as the only analytical technique. In recent years the analytical capabilities of TEM have been augmented with a number of analytical techniques - such as electron energy-loss spectroscopy (EELS), electron holography, Lorentz microscopy, high-angle annular dark-field (HAADF). These have been developed or extended to yet unavailable levels of resolution. The Schottky field-emitters provide stable, reliable, coherent and high-current electron sources that are needed to get the best out of the mentioned analytical techniques.
The development of these analytical capabilities has been a parallel process in many different places and mainly led to dedicated microscopes optimized for one purpose only. This made it almost impossible to get different sets of analytical information from one specimen area simultaneously, and often the data even had to be collected from different specimens.
New Slow-Scan CCD Cameras (SSC) with Frame/Interline CCD Architecture Avoid TEM Shutter Control, Provide Excellent Image Quality and can be Easily Retrofitted
Authors: Hiller SA , Probst W , Seybold V , Zellmann E 
Published: July 2020

Abstract
Since it's introduction into TEM in 1986 [1] SSCs have become an effective and easy-to-use solution for acquiring high quality digital images electronically. Their main advantages are excellent linearity, very high dynamic, high sensitivity, and low noise. These advantages have made SSCs a nondispensable tool for quantitative image analysis. Moreover, since SSCs make high quality TEM images available in a computer within fraction of seconds, on-line image processing and software driven automated TEM tuning has become possible [2]. Many of the experiments which are performed nowadays in the area of high resolution, low dose, holographic reconstruction, and EFTEM [3] would not be possible without the digital input coming from SSCs.
Like recording images with a film sheet camera, digital recording of images with SSC requires control of the TEM beam blanker (shutter) by the SSC synchronised with the image acquisition process.
This blanker (shutter) control is a critical link in the chain to the digital image. Many older TEMs do not have direct access to beam blanking coils, or contrary to modern TEMs their coils are not designed to support hysteresis-free fast beam blanking, what is essential for acquisition of high quality digital images by a SSC.
Tomography on Point Projection X-Ray Microscope Using CCD Images
Authors: Newberry Sterling P 
Published: July 2020

Abstract
Recent advances with the cone-beam approach to tomography at the Advanced Microscopy and Imaging Laboratory (AMIL) have opened the possibility of employing tomography with the Shadow Projection X-Ray Microscope routinely when the specimen properties require it. The AMIL approach has been tested on small objects, without magnification, using conventional dental x-ray sources and a modestly diverging beam angle. The shadow projection Microscope, by contrast has a tenfold greater divergence and magnifies the specimen from unity to three or more orders of magnitude in resolution beyond the previous tests. The reader is reminded of the simplicity of the xray projection method and of the clarity of its images in fig. 1 and 2. The microscope can be operated in any laboratory and readily transported to alternate locations. Now that the AMIL data base and algorithms for tomography can be handled by a Pentium II processor the data gathering and reconstructions can also be managed at any laboratory installation.
Multiport-Readout Frame-Transfer 5 Megapixel CCD Digital System for IVEM Applications
Authors: Fan GY , Peltier S , Lamont S , Young SJ , Dunkelberger Dana G , Ellisman M H 
Published: July 2020

Abstract
A multiport-readout, frame-transfer charge coupled device (CCD) digital imaging system has been successfully constructed and tested for intermediate-high voltage electron microscopy (IVEM) applications up to 400 keV. The system employs a back-thinned CCD, made by MIT Lincoln laboratories, that comprises 2560 × 1960 pixels and a pixel size of 24 μm × 24 μm. With a frame transfer design, the imager fills nearly the entire usable area of a 100 mm-diameter silicon wafer (FIG. 1). In the current implementation, four of the eight on-chip readout ports are utilized in parallel each operating at a pixel rate of 1 or 2 MHz so that the entire CCD array can be read out in as short as ∼0.6 seconds. The frame-transfer readout functions as an electronic shutter which permits the rapid transfer of charges in the active pixels to four light-shielded buffers (FIG. 1) where the charges are readout and digitized while the active area of the CCD is integrating the next frame. At 2 MHz, charge transfer of 980 CCD rows will be completed in under 0.5 ms, which is much shorter than a typical exposure time of a few seconds. The camera head (FIG.2) and control electronics for CCD sensor were packaged by Photometries (Tuscon, Arizona). Two MaxVideo 200 image processing boards from Datacube (Peabody, MA) are used for high speed online imaging processing. The CCD sensor is electronically cooled to ∼ −40°C during operation.
Automated Acquisition of Cryo Electron Micrographs Using Leginon
Authors: Carragher B , Jojic N , Milligan R A , Kisseberth N , Pulokas J , Potter CS , Reilein A 
Published: July 2020

Abstract
Molecular microscopy is one of the most important structural approaches in cell biological investigations and can provide insight into complex biological questions that no other technique can provide. Currently, the technique typically requires the acquisition of very large numbers of transmission electron micrographs from frozen hydrated specimens using low dose techniques. The field is constrained by manual data acquisition methods that are slow, labor-intensive and result in a very low percentage of suitable images. We have developed a system, called Leginon, for automatically acquiring images from a transmission electron microscope. Our first prototype of this system demonstrated that we could acquire 1000 high magnification images per day from negatively stained catalase crystals. We have now extended this system to acquire low dose images of specimens embedded in vitreous ice.
Methods: Specimens were prepared on Quantifoil grids using techniques which have been described previously. The Leginon system uses a Philips CM200 TEM and a Gatan MSC CCD camera and is controlled by the emScope software library. The overall acquisition protocol requires (i) obtaining a low magnification image [660x] of a grid square from a Quantifoil grid (fig. 1a); (ii) automatically identifying holes containing ice of suitable thickness; (iii) acquiring an intermediate magnification image [6600x] of the identified hole (fig. 1b); (iv) identifying features of interest within the hole; (v) focusing at high magnification [38,000x] and finally (vi) acquiring a high magnification image (fig 1c,d).