bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pre-Martensitic State in a Ti50Ni48Fe2 Alloy Studied by Electron Microscopy with Energy-Filtering
Authors: Murakami Y , Ikematsu Y , Shindo D , Oikawa T , Kersker M 
Published: July 2020

Abstract
A Ti50Ni48Fe2 alloy, which is famous as a typical shape memory alloy, exhibits the cubic (parent phase) to trigonal (R-phase) martensitic transformation upon cooling. It is well known that this structural transformation is accompanied by some precursor phenomena, such as appearance of weak diffuse scattering in electron diffraction patterns of the parent phase. Since the diffuse scattering is visible at around 1/31/3 0 and its equivalent positions in diffraction patterns, as similar to the superlattice reflections in the R-phase, it is believed to be closely related with the formation of the R-phase. However, neither structural nor morphological aspect of this pre-martensitic state is clear, since a precise analysis of the weak diffuse scattering is quite difficult along with a conventional electron microscopy, because of the presence of strong background arising from inelastic scattering. The purpose of the present work is to precisely observe the weak diffuse scattering and to reveal the structural and morphological features of the pre-martensitic state by electron microscopy with the aid of a recently developed omega-type magnet.
Observation of Microstructural Evolution of Aluminum Bonding Wires in Power Electronic Package
Authors: Ron Liu D , Chen K , Jih E 
Published: July 2020

Abstract
Power electronic circuits are used in electric vehicle or hybrid electric vehicle to drive the main electric motor. All the transistors and diodes in a sealed power electronic package will experience repeated high current cycling during their service life. The aluminum bonding wires which connect these devices to the rest of the circuit will experience repeated thermal strain cycling. When design a power electronic package, the thermal fatigue durability of these bonding wires would be a concern. A power electronic module with pure aluminum bonding wires of 0.5mm in diameter from a vendor was power cycled with the following schedule. Each transistor in the circuit was on for 10 seconds with the current at 400 Amperes followed by the transistor being off for 30 seconds. The wires from the diodes to the copper trace lines are about twice as long as those from the transistors to the copper trace lines.
Characterization of Cup Earing in Tin Mill Product by X-Ray Diffraction
Authors: Liao K C , Swartz WC 
Published: July 2020

Abstract
X-ray diffraction (XRD) techniques can readily be utilized for the characterization of textures in crystalline materials. The advantages of XRD techniques are: 1) the test is nondestructive, 2) samples can easily be prepared, and 3) data can be collected and analyzed quickly.
Three low-C steel tin mill coils were manufactured during a mill trial which was conducted to optimize the processing parameters necessary for the production of material with low cup earing behavior. The processing parameters evaluated included hot mill conditions (roughing, finishing and coiling temperatures), cold rolling conditions (during first and second cold reduction), and continuous annealing conditions (line speed and strip temperature). Samples A, B, and C were secured from the coil center-width position of each coil, respectively, and were analyzed via XRD.
Properties such as normal anisotropy (r bar) and planar anisotropy (Δ r), have been correlated with an X-ray Intensity Ratio (XIR) at the Technical Center of National Steel.
Cross-Sectional Sample Preparation and Analysis of Intergranular Stress Corrosion Cracks in FE-NI-CR Alloys.
Authors: Thomas LE , Bruemmer SM 
Published: July 2020

Abstract
Transmission electron microscopy in its modern high-resolution analytical form has great potential for elucidating mechanisms of environmental cracking in structural alloys and other materials. Apart from a few pioneering efforts, the difficulties of preparing suitable samples with the original corrosion structures preserved in narrow crack tips have limited contributions of TEM in this area. Recent work involving cross-sectional crack preparation has focused on intergranular stress-corrosion cracking of Fe- and Ni-base stainless alloys in high-temperature water. This presentation will illustrate preparation methods that have proven successful, and describe limitations of the analysis.
The method for preparing cross-section samples suitable for high-resolution TEM characterization is based on earlier work by Lewis et al. It involves preparing a thin section containing cracks filled with epoxy, dimple grinding selected locations near the crack tip, and ion milling. Figure 1 schematically illustrates this method. The first step is to preserve the crack opening characteristics present under loading and protect the crack surfaces during thinning.
Thickness Measurement of Focused Ion Beam Thinned Silicon Crystals Using Convergent Beam.Electron Diffraction and Electron Energy Loss Spectroscopy.
Authors: Delille D , Pantel R , Auvert G , Van Cappellen E 
Published: July 2020

Abstract
1. Introduction
The FIB (focused ion beam) is now widely accepted as the most site-specific TEM preparation tool and as such proves to be highly valuable when analysing ULSI devices. However, using high-energy Gallium ions for milling induces amorphization of the crystal surfaces. A method able to quantify this surface alteration on silicon using a combination of CBED (convergent beam electron diffraction) and EELS (electron energy loss spectroscopy) is presented. CBED is a powerful tool that also can generate an accurate measure of crystal thickness. EELS can yield the total sample thickness, so from the difference the combined amorphous layers can be assessed. Two sets of application results are presented: the first one is obtained on a FIB thinned sample using an ion energy of 50 keV and the second set of results confirms the validity of the proposed method on a mechanically polished specimen with no subsequent ion milling.
Optimization of FIB-Milling Technique for Preparation of TEM Specimens from Copper/Low-K Materials
Authors: Shaapur F , Brazeau D , Foran B 
Published: July 2020

Abstract
Focused ion beam (FIB) thinning of materials to electron transparency is now a routine procedure for preparation of specimens for transmission electron microscopy (TEM) of microelectronic materials and devices. The nano-scale structural damage, including implantation and amorphization due to this ion milling process has been well investigated and documented. In this paper, we discuss the micro-scale structural damage observed in copper/low-k materials and our efforts to minimize the extent of the damage without compromising the overall specimen preparation time.
Figure 1 shows an area-specific cross-sectional specimen prepared from a copper/low-k via-chain test structure using the FIB-milling technique. The procedure involved mechanical thinning of a transverse wafer sliver followed by FIB-milling the area of interest to electron transparency according to conventional steps and conditions' using a liquid Ga+ ion source FIB system. The evidence of structural damage in terms of melting and/or sputtering of the metallization is visible at different areas.
Reactive Ion Beam Etching (RIBE) Technique and Instrumentation for SEM Specimen Preparation of Semiconductors
Authors: Alani R , Mitro RJ , Ogura K 
Published: July 2020

Abstract
Argon ion beam etching has established itself as an alternative technique to “wet chemical” etching for the preparation of cross sectional SEM specimens of semiconductors [1]. Complementing this technique, we are reporting the results of an iodine RIBE method for improved etching/cleaning capabilities with a measurable increase in etching rates as compared to argon ion beam etching. RIBE systems have been used for decades in the semiconductor research/industry for wafer processing, patterning and surface cleaning. This same technique has also been used for high quality TEM specimen preparation of certain semiconductor materials [2,3]. The beneficial aspects of the iodide RIBE technique for surface etching for a variety of semiconductor structures along with the related instrumentation will be discussed. The semiconductor specimens include traditional ICs and more advanced copper technology devices.
The design and construction of the original system used in this work has already been reported [4].
Novel Sample Preparation Methods for Transmission Electron Microscopy Observation of Dopant Profiles in Silicon Devices
Authors: Salvatore Pannitteri  
Published: July 2020

Abstract
I present details of novel sample preparation techniques used for delineating two-dimensional dopant profiles in silicon devices. These techniques are based on selective chemical etch of doped silicon in a mixture of hydrofluoric and nitric acid, or simply in buffered HF. The altered topography of the etched surface is imaged by transmission electron microscopy (TEM). Two different strategies will be presented by focusing on their sensitive, resolution, and field of application.
In the first case the silicon device is subjected to the conventional thinning procedure for TEM observations in cross-sectional configuration. The final thickness is obtained by Ar ion milling and it can vary between 50 to 500 nm. Sample is then immersed in a chemical solution containing HF (40%), HN03 (65%), and CH3COOH (95%) in the ratio 1:10:10. In presence of an intense illumination this mixture preferentially etches those device regions which are doped with boron, while in order to delineate n-type regions, the etching procedure must be performed in the dark.
Microanalytical Techniques for the Determination of Carbonaceous Aerosols in Remote Air and Snow Samples
Authors: Kessler D , Currie A , Newbury E , Windsor ES 
Published: July 2020

Abstract
Remote ice core, snow, and air filter samples can potentially profile past and present atmospheric characteristics, acting as media to preserve populations of particulate matter. Major constituents of these aerosols derive from combustion processes (fossil and biomass) and airborne minerals. Extraction and characterization of these particles with scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) provide morphological and elemental data used in determining the presence and sources of atmospheric aerosols. Due to the minute quantity of carbonaceous particles in the snow and ice samples, ca. 1-10 ng g-1, the microscopist faces several principal challenges to prepare and analyze these samples. First, methodology must be established for particle removal in a clean and quantitative fashion. Secondly, since carbon is contained in many of the particles under analysis, techniques must be established to achieve quantitative carbon X-ray data. The SEM requires optimization in order to analyze the greatest number of particles in the least time.
Optimum Window Size for Quantitating Trace Elements Using Linear Least Squares Fit With Eels
Authors: Ho Ruoya , Feng Jiang Lin , Shao Zhifeng , Somlyo Andrew P 
Published: July 2020

Abstract
Trace element quantitation with EELS is a powerful tool for providing information about elemental distribution in biological and materials sciences. Linear least squares fit (LSF) to standards of the signal and the background is a widely used method for retrieving small signals superimposed on a large, slowly varying background. Theoretically, for most accurate background fitting, the fitting window should be as large as possible. However, when using a large window, there may be a mismatch between the fine structure of the standard and the measured background, due to instability of the instrument and the experimental conditions and radiation damage. This mismatch, distributed over the entire window, can severely affect the accuracy of the small signal extracted with LSF. To overcome this problem, a small window, slightly larger than the signal is often used. Fig. 1 shows the results of extracting a small Ca signal by using respectively, a large and a small window for fitting an EELS spectrum collected from a specimen containing 26.3 mmol/kg dry weight Ca.
Electron Holography of Potential Barriers in Zno Varistors
Authors: Elfwing M , Saunders M , Olsson E 
Published: July 2020

Abstract
ZnO varistor materials are polycrystalline materials that exhibit strong non-linear current-voltage characteristics. Their non-ohmic behaviour makes them suitable for overvoltage protection devices. It is the interfaces between ZnO grains that are the key to the non-linear behaviour of the varistor materials. Previous work has shown that the local microstructure determines the breakdown voltage of the individual ZnO/ZnO interface [1]. The pre-breakdown conductivity and the non-linearity in the breakdown region, which are both crucial to the performance of the varistor, are also affected by the height and the width of the potential barriers. In the present work, electron holography has been used to investigate the potential barriers in ZnO varistor materials.
Electron holograms were recorded at 200kV using a Hitachi HF-2000 field emission gun transmission electron microscope [2]. The electrostatic bi-prism was located near the second image plane. The bi-prism voltage was about 9 V and the fringe spacing in the holograms was about 1 nm.
Visualization of Pure Phase Objects by Amplitude-Division Three Wave Interference
Authors: Hirayama T , Saito T 
Published: July 2020

Abstract
Pure phase objects having low spatial frequency such as electromagnetic fields in a vacuum can be visualized by electron holography or three-wave interference.1,2) Wavefront-division interference using a biprism requires a field-emission electron gun having high spatial coherency. On the other hand, amplitude-division interference using a thin crystal does not need high spatial coherency of electron source, i.e. an ordinary electron microscope with a LaB6 filament is good enough to form lattice fringes of high contrast. This is an advantage of amplitude-division interference.3,4)
We previously reported three-wave interference achieved by using two electron biprisms. Recently, we have realized amplitude-division three-wave interference by using a Si crystal as a splitter of an electron wave. Figure 1 shows the experimental set-up used to form an amplitude-division threewave interference pattern. A thin crystal prepared by ion-milling is installed at the standard specimen position, and a thin carbon film on which latex particles are sticking is placed at the selected area aperture position.
Interpretation of Holographic and Lorentz Images of an Array of Reverse Biased P-N Junctions in a Semi-Infinite Specimen
Authors: Beleggia M , Capelli R , Pozzi G 
Published: July 2020

Abstract
The problem of observing reverse-biased p-n junctions by means of transmission electron microscopy techniques is very challenging both from the experimental and theoretical points of view. In particular, in addition to standard Lorentz microscopy techniques, whose image contrast is able to give some information on the region of high field, also holographic methods have been successfully applied and an interference map of the twodimensional phase on the specimen plane obtained.
In this work we consider, in particular, the theoretical and interpretative aspects, as we have improved a model for the electric field associated to a periodic array of alternating p and n stripes lying in a half plane (physically corresponding to an array of zero-width step junctions) by taking into account that the junctions are tilted with respect to the specimen edge.
Characterization of Multi-Phase and Multi-Component Polymer Systems Using the Atomic Force Microscope
Authors: VanLandingham M , Gu X , Raghavan D , Nguyen T 
Published: July 2020

Abstract
Recent advances have been made on two fronts regarding the capability of the atomic force microscope (AFM) to characterize the mechanical response of polymers. Phase imaging with the AFM has emerged as a powerful technique, providing contrast enhancement of topographic features in some cases and, in other cases, revealing heterogeneities in the polymer microstructure that are not apparent from the topographic image. The enhanced contrast provided by phase images often allows for identification of different material constituents. However, while the phase changes of the oscillating probe are associated with energy dissipation between the probe tip and the sample surface, the relationship between this energy dissipation and the sample properties is not well understood.
As the popularity of phase imaging has grown, the capability of the AFM to measure nanoscale indentation response of polymers has also been explored. Both techniques are ideal for the evaluation of multi-phase and multi-component polymer systems.
Atomic Force Microscopy and Near-Field Scanning Optical Microscopy Study of Quantum-Dot Assemblies and Fractal Films
Authors: Bragg W D , Banerjee K , Campin M J , Ying Z C , Zhu Jane G , Martin J E , Wilcoxon J P 
Published: July 2020

Abstract
Quantum dots and nanocrystalline films are interesting materials due to their novel properties, not achievable from the bulk materials [1]. New materials fabricated by assembling of quantum dots and nanostructured materials exhibit, for example, high optical nonlinearities. Fractal structures [2] can be formed from quantum-dot aggregates or films. Scanning probe microscopy is the essential technique to characterize these nanometer-scaled materials?
Gold nanocluster colloids are synthesized in the interior of surfactant aggregates known as inverse micelles, without the use of water to solubilize the metal salt [3]. The size of the Au quantum dots is well controlled in the colloid synthesis and selected using chromatography. The Au clusters are then sprayed onto a glass slides to form thin films made of Au quantum dots. We have also used the laser ablation technique [4] to grow Ag nanoparticles, fractal aggregates and thin films. These samples have been studied using atomic force microscopy (AFM) and nearfield scanning optical microscopy.
Novel aspects of micro-thermal analysis of polymer blends
Authors: Conroy M , Pollock H M , Hammiche A , Mills G , Weaver JMR , Reading M , Price D M 
Published: July 2020

Abstract
In “ac” scanning thermal microscopy, an “active” thermal probe is used also as a heater, so as to inject evanescent temperature waves into a sample and to allow sub-surface imaging of polymers and other materials [1]. The sub-surface detail detected corresponds to variations in heat capacity or thermal conductivity. By suitably choosing the temperature modulation frequency, and hence the penetration depth of the wave, we control the depth of material below the sample surface that is contributing to the image.
Micro-Thermal Analysis [2, 3] builds upon this technique, in order to add spatial resolution to two well-established methods of chemical fingerprinting, DTA and DMA. In both cases, a temperature ramp is used to subject the sample to “events” such as a glass transition or melting. The chief advantages of using the active thermal probe to provide the temperature ramp as well as the modulation, without the use of a heating stage, are: (a) the data are obtained from localised regions chosen from a previously-obtained thermal image, (b) apart from these regions, the rest of the sample is preserved in its original unheated state.
Imaging Mechanisms in Dynamic Force Microscopy of Polymers
Authors: Haugstad Greg D , Hammerschmidt Jon A , Gladfelter Wayne L 
Published: July 2020

Abstract
Applications of scanning force microscopy (SFM) in polymer studies have flourished in this decade, reflecting (a) the power of SFM to image both structure and propertiesdown to the nanometer scale, and (b) the low cost and ease of getting useful results in ambient environments. One difficulty in SFM of polymers has been damage incurred by soft materials during the imaging process. The problem was alleviated by the development of special dynamic modes of operation, in which the probe spends little or no time in contact with the polymer surface. Such modes were dubbed “tapping”, “intermittent-contact”, “non-contact”, “near-contact”, etc. As studies proliferated, it became apparent that different researchers were using different terms to refer to the same apparent imaging mechanism, or the same term to refer to different imaging mechanisms. This quandary derived from a poor understanding of exactly how the SFM probe interacts with the sample surface.1-3,5
Structure, Flexibility and Intramolecular Forces Observed on Individual Proteins Using Afm
Authors: Müller Daniel J , Engel Andreas 
Published: July 2020

Abstract
Atomic force microscopy (AFM) allows the surfaces of native biological macromolecules to be imaged in aqueous solution with submolecular resolution. Short range forces govern the interactions between the AFM tip and the sample and produce the submolecular information of high resolution topographs. In contrast, the long range electrostatic double-layer (EDL) force can be adjusted by pH and electrolytes to distribute the force applied to the AFM tip over a large sample area [1]. As demonstrated on fragile biological samples, adjustment of the electrolyte solution results in a local reduction of both vertical and lateral forces between the AFM tip and proteineous substructures. Consequently, the deformation of the native protein is minimized and polypeptide loops of individual proteins were imaged in aqueous solution with a lateral resolution &lt; 5 Åand a vertical resolution &lt; 1 Å (Fig. 1).
Multimodal Atomic Force Imaging of Open Hemichannelinduced Modulation of Cell Volume and Viscoelastic Properties
Authors: Rhee Seung K , Quist Arjan P , Lin Hai , Almqvist Nils , Lai Ratneshx 
Published: July 2020

Abstract
Hemichannels from two single cells can join upon contact between these cells to form gap junctions - an intercellular pathway for the direct exchange of ions and small metabolites. Using techniques of fluorescent dye-uptake assay, laser confocal fluorescence imaging and atomic force microscopy (AFM), we have examined the role of hemichannels, present in the non-junctional regions of single cell plasma membrane, in the modulation of cell volume.
Antibodies against a gap junctional protein connexin43, were immunolocalized to nonjunctional plasma membrane regions of single BICR-MlRk k (breast tumor epithelial) cells, KOM-1 (bovine aortic endothelial) cells, and GM04260 (AD-free human) fibroblast cells. In the absence of extracellular calcium, cytoplasmic uptake of Lucifer yellow (LY) but not of dextran-conjugated LY was observed in single cells. Dye uptake was prevented by gap junctional inhibitors, ẞ-glycyrrhetinic acid (ẞGCA) and oleamide.
Atomic Force Microscopy (Afm) of Chromatin Fibers: What Can We Learn?
Authors: Leuba SH , Bash R , Lohr D , Lindsay S M , Zlatanova J 
Published: July 2020

Abstract
DNA in the eukaryotic nucleus is not naked. Instead, it is complexed at frequent intervals with an equal molecular mass of histones to form nucleosomes. In the nucleosome, ∼146 bp of DNA are wrapped around a core histone octamer composed of two copies each of histones H4, H3, H2B, and H2A. The family of linker histones (H1, H5 and H1°) bind to the DNA between successive nucleosomes and help maintain the three-dimensional arrangement of nucleosomes within the chromatin fiber. AFM studies of chromatin fibers with the histones either selectively trypsinized or selectively reconstituted demonstrate a specific role for the H3 N-termini in maintaining fiber structure, in conjunction with the 80 amino acid linker histone globular domain. These AFM results structurally agree with the location of the H3 N-termini in the histone octamer or the nucleosome core particle.