bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructure of Copper Films and its Oxides Prepared by Electron Beam Evaporation and ECR Plasmon Oxidation
Authors: Campin MJ , Barbour JC , Braithwaite JW , G. Zhu Jane 
Published: July 2020

Abstract
The corrosion of copper is an important area in materials science because of the widespread use of copper in structural devices and electronics. These widespread uses in conjunction with its thermodynamic instability in most atmospheric conditions have prompted numerous atmospheric copper corrosion studies. The goal of these investigations has been to identify the underlying mechanisms by which corrosion proceeds in order to prevent any detrimental corrosion effects. Despite these studies, the microstructure of copper and its oxides remains poorly understood. Therefore, our investigation is concentrated on determining this microstructure.
In our investigation, copper films are electron-beam evaporated onto SiO2 coated Si wafers and then exposed to an electron-cyclotron-resonance (ECR) O2 plasma, which simulates an aggressive oxidizing environment. The ECR-grown oxide is fully oxidized to CuO at the surface and changes to CU2O further into the sample. The thickness of the oxide layer is controlled by the sample exposure time to the ECR plasma.
Photon and Electron Beam Induced Phase Transformations in CDS Nanocrystals
Authors: Gajdardziska-Josifovska M , Lazarov V , Reynolds J , Yakovlev V V 
Published: July 2020

Abstract
One of the great challenges of nanotechnology is how to produce and modify objects at nanoscale dimensions. The search for physical and chemical methods for controlled synthesis, modification and characterization of semiconductor nanocrystals is of special interest due to their novel electronic and optical properties. Recently we have achieved the first laser-induced phase transformation in semiconductor nanocrystals [1], irradiating colloidal solutions of CdS nanocrystals with 7 ns pulses of 532 nm wavelength. We used established wet-chemistry methods to synthesize the CdS nanocrystals, and a combination of electron microscopy methods to determine the structure, size and composition of the nanocrystals. In the present paper we report a wavelength dependence of the laser-induced phase transformations in CdS. We also explore electron-induced transformations in comparison with their photon counterparts.
Aqueous colloidal solutions of CdS nanocrystals were prepared by mixing of CdCl2 with Na2S in the presence of Sodium Mercaptoacetate and HC1 [2].
Characterization of Magnetically Aligned Single Wall Carbon Nanotubes Using Transmission Electron Microscopy
Authors: Smith Brian W , Luzzi David E 
Published: July 2020

Abstract
The ability to align single wall carbon nanotubes (SWNTs) is paramount for harnessing their remarkable anisotropic electronic and mechanical properties. D.A. Walters et al. (Rice Univ.) have succeeded in aligning milligram quantities of SWNTs using a strong magnetic field. The nanotubes were aligned in suspension and simultaneously filtered to produce a thin membrane. However, small angle X-ray scattering (SAXS) — the traditional technique for obtaining fiber patterns — has proven ineffective in determining the degree of alignment due in part to carbon's weak atomic scattering factor for X-rays.
In the present work we succeed in quantitatively characterizing this membrane using transmission electron microscopy (TEM). A self-supporting sample was prepared by peeling ∼ 0.5 mm long strips from the material. TEM images reveal that the membrane itself is not a single, large bundle (i.e. rope) of SWNTs. Instead, it has a prominent texture, corresponding to many ropes aligned parallel to the direction of the applied magnetic field.
Statistical Significance of Discrete Soot Particulate Microanalysis
Authors: Bell David C 
Published: July 2020

Abstract
Soot particles are generated from a number of sources, including auto emissions, aircraft emissions and various domestic and industrial combustor sources. Particle size and composition has been the focus of recent Environmental Protection Agency directives, especially due to the impact of small particulates on the inner urban environments. Single particle microanalysis is advantageous in these studies since, morphology and composition can be examined simultaneously. When a small sample size is available, single particle microanalysis is the only possible micro analytical approach. Chemical fingerprinting using the energy dispersive x-ray spectroscopy (EDS) signature of trace elements contained in the particles has shown remarkable source based uniqueness. Previous studies involving diesel soot particulates have indicated that most samples analyzed on a discrete basis are reasonably homogeneous, but questions still remain as to the ultimate statistical limit of this technique.
Initial Kinetics of Copper Oxidation in Different Oxidizing Atmospheres as Studied by In Situ UHV-TEM
Authors: Bharadwaj Mridula D , Tropia Lori , Gibson Murray , Yang Judith C 
Published: July 2020

Abstract
It is of fundamental and practical interest to understand the oxidation process since a desirable property for metals is resistance to corrosion. But there is a wide gap between information provided by surface science methods and that provided by bulk oxidation studies. The former have mainly examined the adsorption of ∼ 1 ML of oxygen on the metal surface, where as both low and high temperature bulk oxidation studies have mainly focused on the growth of an oxide layer at the later stages of oxidation.
We are probing the initial oxidation stage of a model metal system by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) in order to gain insights into the initial kinetics of oxidation. We have previously shown that the growth mechanism of the cuprous oxide is initially dominated by oxygen surface diffision.
Metastability in co-Tiintermetallic Compounds Sintered by SPS.
Authors: Martínez-Sánchez R , Espinosa-Magaña F , Cabañas-Moreno J G , Bejar-Gómez L , Díaz de la Torre S 
Published: July 2020

Abstract
The mechanical alloying (MA) process is an effective method to develop strategic materials with novel structures. These can be solid solutions (even in immisible systems), amorphous phases, fine particle sized and nano-metric crystals etc. Conventional powders metallurgy routes can process the mechanical alloyed products. However, the novel features conferred into the powders, can be lost during the sintering operations. The spark plasma sintering process (SPS) is an alternative route to dense mechanically alloyed products at a high grade while retaining their novel structures. Co-Ti alloys were produced by mechanical alloying the elemental powders mixtures with nominal composition Co50Ti50 (at. %). Details on the preparation and characterisation of the milled products can be found in related publications. Densification of the powders products was conducted using a Dr. Sinter equipment. Previous studies on Co-Ti alloys processed by MA and SPS have shown that the final products are composed of mixtures of metastable intermetallic compounds.
Inverse Porous Nickel Nanostructures From Opal Membrane Templates
Authors: Zhou WL , Xu L , Frommen C , Baughman RH , Zakhidov AA , Malkinski L , Wiley JB 
Published: July 2020

Abstract
Currently there is a strong interest in fabricating nanoporous metal arrays using various template methods. Porous opal membranes of close-packed silica beads, for example, have a unique template structure due to their tetrahedral and octahedral interstices. Such structures can be infiltrated with a variety of materials, especially metals, to form continuous inverse networks. Interest in these forms comes from their potential application in a variety of areas including photonics, magnetics, catalysis, and thermoelectrics. In this paper, we present electron microscopy characterization of inverse nickel photonic materials prepared by electrodeposition method.
Electrodes were formed from opal pieces (typically 7 x 10 x 1.5 mm with silica spheres about 300 nm) by first depositing about 0.5 micron thick copper films on one side of the piece with magnetron sputtering. A length of wire was then attached to the copper backing with silver paste.
TEM Study of Copper Oxide Nano-Particles in Silica Glass Prepared by Co-Implantation of Copper and Oxygen Ions
Authors: Wang S X , Nakao S , Wang L M , Miyagawa Y , Miyagawa S , Ikeyama M 
Published: July 2020

Abstract
The formation of nano-particles in silica glass by ion implantation has attracted great attentions because of the applications for visible luminescence and nonlinear optical devices. Ion implantation is a unique technique for producing nano-particles, with the advantages of high controllability of beam position, depth and distribution of projectiles, concentration, high purity and ability to overcome low solubility restrictions.
Optical grade silica glasses were used as the substrates. Ion implantation was performed with a 1.7 MV tandem-type ion accelerator (NEC 5SDH-II pelletron accelerator) of NERIN. The substrates were implanted with 1.0 MeV O+ and 1.8 MeV Cu+. Projected ranges were calculated by SRIM-2000 to be 1.5 μm (for O+) and 1.4 μm (for Cu+). Samples were cooled with liquid nitrogen to reduce the beam heating. The ion current densities of O+ and Cu+ were 6 and 2 μA/cm2, respectively.
From Dynamics to Details: Live-Cell Light Microscopy and Highresolution (25 nm) Soft X-Ray Microscopy
Authors: Larabell C A , Yager D , Meyer-Ilse W , Rowning B A 
Published: July 2020

Abstract
Imaging cells using a variety of microscopy techniques has generated information about the organization of cells and subcellular structures that is the foundation for understanding cell function. Invaluable information about the dynamics of cells has been obtained from a variety of light microscopy techniques, and the exquisite structural details of cellular organization have been obtained from electron microscopy. Each of these approaches, however, has its limitations. The resolution provided by light microscopy is limited by the wavelength of light, whereas the specimen preparation required for examining cells using electron microscopy is extremely tedious and time consuming. We show that soft x-ray microscopy can bridge the gap between these two forms of microscopy by providing a method for examining whole, hydrated cells up to 10 um thick at 25 nm resolution. Examination of rapidly frozen cells provides information that closely approximates that seen in living cells.
Troponin-Tropomyosin Control of Thin Filament Activity Revealed by Electron Microscopy and 3-D Reconstruction.
Authors: Lehman W , Hatch V , Rosol M , Korman V , Horowitz R , Van Eyk J , Tobacman L S , Craig R 
Published: July 2020

Abstract
Muscle contraction and the actomyosin ATPase that drives the contractile process are switched on and off by changes in sarcoplasmic free Ca2+ -concentration. In skeletal and cardiac muscles, on-off switching is mediated by the actinassociated protein tropomyosin and by the troponin complex. While the details of this mechanism are still subject to debate, it is well-accepted that tropomyosin strands move to sterically block and unblock myosin binding sites on actin, thereby controlling actomyosin ATPase and consequently contraction. It is also well known that the Ca2+- dependency of the movement of tropomyosin on actin is governed by troponin.
As a means of studying tropomyosin movement and the influence of troponin, we have used cryo-EM, negative staining and 3-dimensional helical reconstruction to define the positions of tropomyosin and troponin on thin filaments. We examined various preparations of native isolated filaments and filaments reconstituted with wild-type and mutant proteins.
Microscopy of Muscle in the 19th and 20th Centuries
Authors: Huxley Andrew F 
Published: July 2020

Abstract
In the 19th century, the microscope was the principal tool of biologists. The ordinary light microscope is designed to work on specimens that absorb light, but most unstained biological specimens do not absorb light appreciably and almost nothing is visible when such a specimen is viewed with the full aperture of the objective illuminated. However, they do show appreciable differences of refractive index, corresponding to variation in the concentration of solids, and the 19th century microscopists understood how to interpret the image when these were made visible by reducing the illuminating aperture and going slightly out of focus. If the objective is brought closer to the specimen (low focus), regions with high refractive index appear dark (positive image), and it became customary to use this setting, as in Fig. l (upper). As a result, the A bands of striated muscle fibres, with refractive index higher than the I bands, came to be known as the dark bands, although they appear bright with high focus.
Electron Microscopy and Excitation-Contraction Coupling. A Tribute To L.D. Peachey
Authors: Franzini-Armstrong Clara 
Published: July 2020

Abstract
Muscle contraction is activated by delivery of calcium from the internal membrane system of muscle cells, the sarcoplasmic reticulum (SR), to the myofibrils. Muscle relaxation ultimately depends on the sequestering of calcium back into the SR. In general, skeletal muscle is the most efficient in holding on to its calcium and calcium movements across the surface membrane are minimal during muscle activity. Cardiac muscle is less efficient and its activity is accompanied by significant movements of calcium across the surface membrane. Understanding of the calcium movements during muscle activation has relied heavily on structural information using the electron microscope and Lee Peachey was at the forefront in establishing structure function correlations. He talked the physiologists language and thus caught their attention.
Four stages can be detected in the contribution of EM to the unraveling of the calcium story. First the membrane systems involved were identified, and quickly sorted into two types on the basis of structural characteristics dictating specific functions.
X-Ray Microanalysis in the STEM
Authors: Williams D B , Watanabe M 
Published: July 2020

Abstract
Commercial TEM/STEMs are ill designed for quantitative X-ray microanalysis of thin foils. There have been no fundamental advances in their design since the first instruments appeared in the mid- 1970s. These instruments had thermionic sources with useful probe sizes of ∼10 nm, small (∼ 0.1 sr) detector collection angles, illumination systems giving serious levels of stray radiation, substantial hydrocarbon and water-vapor contamination due to the poor vacuum (∼10-5Pa) and sliding o-ring seals on unstable side-entry goniometer stages. The instruments lacked a direct measure of the probe current at the specimen. Often a 60 s accumulation time resulted in enough drift or contamination that the microanalysis was not trustworthy and spatial resolution was compromised. Today's modern TEM/STEMs, apart from replacement of thermionic source with a FEG, are little better.
Dedicated STEMs however, have invariably offered better X-ray performance. The first VG HB 5 DSTEM became available, also in the 1970s, and the X-ray performance improved through to the latest design (the VG HB 603) in the mid-1990s.
High Spatial Resolution Analytical Investigation of InGaAs/GaAs Quantum Dots
Authors: Catalano M , Crozier P , Taurino A , Passaseo A , Cingolani R 
Published: July 2020

Abstract
The improvement of growth techniques in the characterization of semiconductor nanostructures, has recently resulted in the realization of quasi-zero dimensional semi-conducting devices (quantum dots) of excellent performances and of reproducible quality (1,2). The design and fabrication of these devices strongly depends on the ability to control parameters that influence the quantum confinement namely the shape, dimension and size distribution of the dots. High spatial resolution structural and analytical techniques are crucial to obtain nanoscale information about the shape of the dots, the structural and chemical abruptness of the interfaces, and the composition of the dots (3).
In this paper we show the results of a structural and chemical characterization of In0.5Ga0.5As/GaAs quantum dots grown by low-pressure metal organic chemical vapor deposition (LP-MOCVD) on a (100) GaAs substrate. The growth was performed in a horizontal LP-MOCVD system (AIXTRON 200 AIX).
Comparison of Elemental Detection Using Microcalorimetry, SIMS, AES and EDS (SEM, STEM, and TEM)
Authors: Vartuli C B , Stevie F A , Wollman D A , Antonell M , Irwin R B , McKinley J M , Shofner T L , Purcell B M , Anderson S A , To B 
Published: July 2020

Abstract
Cu contamination has become a larger concern as more semiconductor fabrication facilities switch from aluminum to Cu interconnects. The resolution limits of several analytical tools are compared to determine the optimum analysis methods for detecting Cu contamination in semiconductor materials. The elemental detection limits of Secondary Ion Mass Spectrometry (SIMS), Auger Electron Spectrometry (AES), Microcalorimetry and Energy Dispersive Spectrometry (EDS) systems on Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), and Transmission Electron Microscopy (TEM) instruments are evaluated for Cu in WSix.
Two different samples were used in this study. One sample has a high uniform concentration (0.9% atomic, 0.7 wt.%) of Cu that was incorporated during the sputter deposition of WSi2. A lower concentration was ion implanted with 63Cu to a dose of lel4 cm-2 and has a peak concentration of lel9 cm"3, or 0.02% atomic.
A Tilting Procedure to Enhance Compositional Contrast and Reduce Residual Bragg Contrast in EFTEM Imaging of Planar Interfaces
Authors: Moore KT , Stach EA , Howe JM , Elbert DC , Veblen DR 
Published: July 2020

Abstract
When acquiring energy-filtered TEM (EFTEM) images of a crystalline material, the detrimental effects of diffraction contrast can often be seen in raw energy-filtered images (EFI) (i.e., pre-edge and post-edge images), jump-ratio images and elemental maps as residual diffraction contrast. Residual diffraction contrast occurs in raw EFI because of plural scattering (i.e., inelastic-elastic and elastic-inelastic electron scattering) and in jump-ratio images and elemental maps because background removal procedures often are unable to completely account for intensity changes due to dynamical effects (elastic scattering) that occur between pre-edge and post-edge images acquired at different energy losses.
It is demonstrated in these experiments that, when examining a planar interface, EFTEM images have increased compositional contrast and decreased residual diffraction contrast when the sample is oriented so that the interface is parallel to the electron beam, but not directly on a zone axis.
Spectroscopy and Imaging With Energy-Filtering Tems: Parameters That Matter
Authors: Kothleitner G , Brink H A 
Published: July 2020

Abstract
Spectroscopy and imaging techniques based on electron energy-losses (EELS), which are accessible through energy-filtering transmission electron microscopes (EFTEMs), have proven to be important tools in both materials and life science investigations.
The two most widely used techniques on commercially available EFTEMs are elastic imaging and elemental mapping. Elastic imaging enhances image resolution and contrast by extracting the zero-loss signal and eliminating the inelastic background, whereas elemental mapping, which involves signals coming from element-specific inner-shell ionization edges, is employed to form two dimensional elemental distribution images. In both cases relatively large energy windows of a range of 10 to 30eVare typically used to form energy-filtered images with usually low to moderately high magnifications.
There is however much more information available in an EELS spectrum, which is contained in the detailed fine structure within 0-20eV of a core excitation edge (ELNES) or in the very low energy-loss up to 5eV.
Using Electron Energy-Loss Spectroscopy (EELS) To Study Rare Earth Elements In Natural Crystals
Authors: Xu Huifang 
Published: July 2020

Abstract
Because of similar chemical properties of the rare earth elements (Ree), whole series of the Ree may occur in natural Ree-bearing crystals. Relative concentration of the Ree may vary as the crystallization environments change. Electron energy-dispersive spectroscopy (EDS) associated with TEM is unable to resolve Ree and other coexistence elements, such as Ba nd Ti, because of peak overlap and energy resolution (∼ 150 eV) of EDS. Figure A indicate multiple peaks from Ce only. The Cu peaks are from Cu grid holding the specimen. Electron energy-loss spectroscopy (EELS) with energy resolution of &lt; 1 eV is able to resolve all Ree in natural Ree-bearing crystals.
Natural carbonate crystals from a Ree ore deposit were investigated by using EELS associated with field emission-gun (FEG) TEM. The crystals are in a chemical series of BaCO3 - Ree(CO3)F [1]. In Figure B, EEL spectra A and B are from Ce-rich and La-rich bastnaesite (Ree(CO3)F), respectively; spectrum D is from cordylite (BaCO3 (Ree(CO3)F); spectrum E is from huanghoite (BaCO3 Ree(CO3)F), spectrum F is from BaCO3; spectrum C is from an unknown Ree-rich phase.
Low Energy Electron Transmission Through Thin Polymer Films
Authors: Kuhlman W , Libera M , Gauthier M 
Published: July 2020

Abstract
While transmission and beam damage have been well documented in the TEM at high accelerating potentials, considerably less is known about these phenomena at lower accelerating potentials. Imaging using low accelerating potentials may be attractive as an analytic technique, because chemical degradation associated with electron beam irradiation in organic macromolecules may be a function of accelerating potential (e.g. 1, 2). The present work examines low-energy electron transmission through thin polymer films and beam damage produced by low energy (∼ 0.5-10 keV) electrons.
Thin films of polystyrene were prepared by allowing a ∼ 0.005% solution of G3-5k arborescent polystyrene in toluene to evaporate on a holey carbon film. In solution, this arborescent polystyrene consists of spherical molecules of order 45 nm in diameter (3). When evaporated from dilute solution on a holey carbon film, monolayer thick self-assembled membranes form in some of the holes (figs. 1 and 2). The resulting films are highly reproducible in thickness and have a relatively uniform morphology (fig. 3).
Polymerization and Three Dimensional Reconstruction of Deoxy-Sickle Cell Hemoglobin Fibers in High and Low Phosphate Buffers
Authors: Wang Zhiping , Kishchenko Gregory , Chen Yimei , Josephs Robert 
Published: July 2020

Abstract
The amino acid substitution (B Glu → G6 Val) results in the conversion of Hemoglobin A (HbA) to sickle cell hemoglobin(HbS) which is responsible for sickle cell disease. Under physiological conditions this substitution causes a reduction of the solubility of HbA from about 340 mg/ml to 165 mg/ml (for HbS). One consequence of the reduction in solubility is that HbS polymerizes to form long fiber like structures about 240Å in diameter. The formation of these fibers causes sickle cell disease. The fibers fill the red cell and cause it to assume a characteristic sickle shape. More significantly the fibers cause the red cell to become rigid and, as a result, sickled cells can block blood flow in the capillaries. Understanding the polymerization process in detail is important for understanding the pathophysiology of sickle cell disease and for developing a specific therapy that could be used in its treatment.