bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inelastic Electron Scattering and Total Reflectivity in RHEED
Authors: Yao Nan , Cowley John M. 
Published: June 2020

The detailed studies of the electron energy distribution of the specular reflected beam and the total reflectivity for a platinum single crystal (111) surface under a variety of diffraction conditions were carried out on a JEM-2000FX transmission electron microscope equipped with a Gatan 666 paralleldetection electron energy loss spectrometer.Five different diffraction conditions are characterized as D1-D5. With D1, the specular reflected spot falls in an intersection of a parallel Kikuchi line with a parabola; with D2, the specular reflected spot coincides with an intersection of the Kikuchi lines running parallel to and inclined to the crystal surface; with D3, that is pure specular Bragg reflection (the specular reflected spot crosses only the parallel Kikuchi line); with D4, the specular reflected spot intersects only with a parabola; and with D5, the specular reflected spot falls only on the oblique K-lines. A series of specular reflected beam energy loss spectra collected from the first four different diffraction conditions is shown in figure 1, where the spectra 1-4 correspond to conditions D1-D4, respectively.
Electron Beam Damage of Multiple Monolayers
Authors: Ohno Tamotsu 
Published: June 2020

Previous studies on electron beam damage of organic crystals have indicated that the rate of fading of electron diffraction patterns is dependent on specimen thickness. In our previous work we had investigated behenic acid monolayer crystals as well as multilayer crystals. The experimental result showed that the critical dose. De, defined as the dose at which the peak intensity of the first order diffraction spot falls to 1/e of the initial value, increased linearly with specimen thickness in the range of 1-4 layers. The present experiment was carried out using the thicker specimen in order to investigate the decay process of multilayer crystals as well as the upper 1imit of critical dose.The multiple monolayers of behenic acid were prepared with the same technique used in the previous experiment. Examined specimens were z-type Langmuir-Blodgett films. The specimens were mounted on carbon coated formvar support films. To avoid charging of the specimen, thick specimens were coated by thin evaporated carbon film.
Characterization and Reissue of SRM 2063 Thin-Film Glass Standard
Authors: Phelps J. M. , Steel E. B. 
Published: June 2020

X-ray energy-dispersive spectrometry (EDS) is an essential tool for chemical analysis .with an electron microscope. Quantification of an acquired spectrum is typically preformed using a “relative elemental sensitivity factor” or “k factor” approach. Because of differing instrumental and detector configurations, detector efficiencies and ionization cross sections, these sensitivity factors must be determined for individual instruments. SRM 2063 is the reissue of a thin film Standard Reference Material of known chemical composition, density, thickness, stability, and homogeneity to provide characteristic x-ray peak locations and intensities for elements in the 1 - 8 keV region. The experimental procedure utilizes several different techniques to characterize the samples and limit analytical bias.The original issue of SRM 2063 was produced by NIST personnel at a commercial laboratory using their ion beam deposition system. For the reissue of SRM 2063, a 10 cm diameter ion beam deposition system was acquired by NIST and used to sputter a fully characterized silicon, magnesium, calcium, and iron glass.
Comparison of experimental and theoretical XEDS k-factors as a function of accelerating voltage
Authors: Zaluzec Nestor J. 
Published: June 2020

For nearly fifteen years k-factor measurements have been made by varying the composition of the standards at fixed accelerating voltage and measuring the change in the experimental k-factor with atomic number. From this data a “best model” of the ionization cross-section is frequently proposed for use in quantitative analysis, however it is valid only at that fixed voltage. Few if any studies seek to determine the systematic variation in the k-factor with accelerating voltage. In this paper experimental measurements of the variation in the k-factor as a function of accelerating voltage are reported. With the advent of medium voltage analytical microscopes routinely available to the microscopy community, it becomes essential to understand how the k-factor varies with accelerating voltage in order that errors in quantitative analysis can be avoided should experimental or theoretical k-factors from lower voltage instruments are applied to the medium voltage regime.Electropolished specimens of β-NiAl were studied in a Philips CM30T electron microscope, equipped with a Be-Window Si(Li) detector interfaced to an EDAX 9900 Energy Dispersive Analysis System.
Channelling Enhanced X-Ray Microanalysis of the Preferred Substitution of Ti, Cr and Co Atoms in Sendust (Fe-9.6wt.%Si-5.5wt.%Al) Alloys
Authors: Sato Kaoru 
Published: June 2020

Sendust (Fe-9.6wt%Si-5.5wt%Al) is a well-known soft magnetic material. Attempts have been made recently to improve the corrosion resistance of this alloy by adding a fourth and/or a fifth element. Since the excellent magnetic properties of Sendust have been reported to be deeply related to its crystal structure, the DO3 structure, it is of vital importance to determine the crystallographic sites those additional elements occupy. In the present work I will report the results obtained for the site occupation of Ti, Cr and Co in Sendust alloys using the ALCHEMI method.Sendust containing 4.0%Cr, 3.0%Co+0.5%Nb and 2.0%Ti alloys were arc melted, then furnace-cooled from 1250°C. TEM specimens were prepared in a twin jet electropolisher using 5% perchrolic-acetic acid and the final thinning was done using an ion milling machine. The ALCHEMI experiment was performed in a Philips EM420T equipped with an EDAX 9900 system.All the specimens observed exhibited the diffraction spots which are associated with the DO3 structure (Fig. 1).
Identification by Electron Microdiffraction of Intermetallic Phases in a Duplex Stainless Steel
Authors: Redjaïmia A. , Morniroli J.P. , Metauer G. , Gantois M. 
Published: June 2020

2D and especially 3D symmetry information required to determine the crystal structure of four intermetallic phases present as small particles (average size in the range 100-500nm) in a Fe.22Cr.5Ni.3Mo.0.03C duplex stainless steel is not present in most Convergent Beam Electron Diffraction (CBED) patterns. Nevertheless it is possible to deduce many crystal features and to identify unambiguously these four phases by means of microdiffraction patterns obtained with a nearly parallel beam focused on a very small area (50-100nm).From examinations of the whole pattern reduced (RS) and full (FS) symmetries the 7 crystal systems and the 11 Laue classes are distinguished without ambiguity (1). By considering the shifts and the periodicity differences between the ZOLZ and FOLZ reflection nets on specific Zone Axis Patterns (ZAP) which depend on the crystal system, the centering type of the cell and the glide planes are simultaneously identified (2). This identification is easily done by comparisons with the corresponding simulated diffraction patterns.
Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns
Authors: Mansfield John F. , Crawford Douglas C. 
Published: June 2020

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:Where ξg, is the extinction distance for that reflection and ni is an integer.
Atomic Thermal Vibration Phase Correlation in Electron Diffraction and Imaging
Authors: Wang Z. L. , Bentley J. 
Published: June 2020

Consideration of phase correlation between localized inelastic events occurring at different atomic sites remains one of the major obstacles in the dynamic calculations of either the Bloch wave theory or the generalized multislice theory. The former is restricted by the 3-D periodic assumption of the transition matrix and the latter is limited by the coherent treatment of the inelastic excitation within the same slice. To approach this problem properly, one starts from the coupled Schrodinger equations,Ψ0 is the elastically scattered wave of energy E0, Ψn describes the inelastically scattered wave of the nth excited state of energy En = E0 - εn, and H'nm are the transition matrix elements. Taking Ψn = ϕn(z)Ψn0(r), where Ψn0(r) satisfies the elastic scattering Schrodinger equation of different wave vectors,and under the small angle approximation, Eq. (1) becomesEquation (2) can be solved with established elastic scattering theory, such as the multislice method.
Development of the 25 micron pixel imaging plate system for TEM
Authors: Ogura N. , Yamada T. 
Published: June 2020

In 1986, we reported that the Imaging Plate (IP) could be applied to the recording material for TEM. In 1990, we reported the first commercial IP system for TEM, which was co-developed with JEOL Ltd. This time, we developed a new IP system that has the following remarkable concepts.1. Enormous amount of information and high image quality The IP is read by the IP Reader at a pixel size of 25 microns and at a gray level of 16384 (14 bit). One image consists of 3760 × 3000 pixels. This means the image satisfies two essential requirements, i.e., high resolution and large area, at the same time. As the new sophisticated scanning system and the 400 dpi high-quality color printer (Fujix Pictrography 3000) have been combined, the final hard copies are almost identical to photographic films.2. Applicable to most TEMs The size of the IP is 99.6 × 80.9 mm, which is the same as that of photographic films mainly used in the USA, so the IP can be applied to most TEMs of any manufacturer in the world.
Near-field plasmon-resonance scanning microscopy
Authors: Schultz Sheldon 
Published: June 2020

In the past few years the field of near-field scanning optical microscopy (NSOM) has developed rapidly with applications spanning all the physical sciences. A key goal of this form of microscopy is to obtain resolution at levels well beyond those possible with the usual far-field optics. In contrast to far-field optics, which is bounded by the well known limits imposed by diffraction, near-field optics has no "in principle" fundamental lower limit in lateral size, at least down to atomic dimensions, although in practice, signal-to-noise considerations may restrict the application of NSOM to a few nanometers.The simplest form of NSOM to visualize is based on the principle of a sub-wavelength aperture (with D/λ < < 1) in an opaque plane. Light impinging on this aperture may only be transmitted through the diameter D, and, indeed, were it observed in the far-field, would be spread out over the entire half space due to diffraction. However, if the sample to be studied is placed in the near-field of the aperture, say within a distance D away, the region illuminated will also be restricted to a lateral dimension very close to D.
Resolution beyond the diffraction limit: 4PI-confocal-, STED-, and GSD- fluorescence microscopy
Authors: Hell Stefan W. , Hanninen Pekka E. , Schrader Martin , Wilson Tony , Soini Erkki 
Published: June 2020

In far-field light microscopy resolution is determined by diffraction. In a far-field light microscope such as the confocal scanning light microscope, the resolution is governed by the extent of the squared intensity distribution in the focal region. Precise measurements of the confocal PSF have shown that the axial and lateral resolution of a confocal microscope (NA=1.4 oil, 1= 633 nm) is 520nm and 200nm (FWHM), respectively. At a wavelength of 375nm, this amounts to a resolution of 300 nm (axial) and 120 nm (lateral), obtainable with a standard confocal microscope of high aperture.A 3-7 fold increase in axial resolution is achieved with a 4Pi-confocal microscope. The 4Piconfocal microscope uses two high numerical aperture objective lenses that are used coherently for illuminating or detecting the same point in the object space. The present paper deals with the latest developments in the field of 4Pi-confocal microscopy. The Optical Transfer Functions (OTF) of 4Piconfocal microscopies with 4Pi-illumination (type A), 4Pi-detection (type B), and 4Pi illumination and detection (type C) are measured and compared with their standard confocal counterpart.
A microscopic system for high-resolution electron crystallography
Authors: Fujiyoshi Y. , Murata K. , Mitsuoka K. , Hirai T. , Miyazawa A. , Kimura Y. 
Published: June 2020

High-resolution electron cryo-microscopy is one of good candidate for structure analysis of membrane-protein, and also actually analyzed the structure of membrane-proteins such as bacteriorhodopsin (bR) and plant light-harvesting complex (LHC). By developing an expeditious method for structure analysis up to atomic or near atomic resolution, we would like to interpret a function of protein from the structural point of view. However, there are some difficulties in electron microscopy for structure analysis of protein. Especially, the most serious problems are the specimen damage caused by electron irradiation, the denaturation of biomolecules caused by dehydration and missing high-resolution data on electron micrographs at high-tilted angle.The irradiation damage at 8K has been found to be reduced to 1/20 compared with that at room temperature. We have, therefore, developed a high-resolution electron cryo-microscope and improved it by which images can be recorded with higher resolution than 3 Å at a specimen-stage temperature of 4.2 K, even when the specimen is highly tilted. The highly tilted data are essential for reduction of the missing corn effect.
X-ray standing wave measurements of adsorbates on metal surfaces
Authors: Heskett D. , Shi X. , Su C. , Xu P. , Corridon D. , Berman L E. , Kao C.-C. , Bedzyk M.J. 
Published: June 2020

One of the main goals in surface science is the determination of the geometric structure of the surface, including the local registry of adsorbed atoms and molecules on surfaces. The X-ray Standing Wave (XSW) technique offers a powerful method of locating the positions of atoms and molecules in and on single crystals1. This technique is now being employed with increasing frequency with the availability of x-ray radiation synchrotron sources, but is still underutilized with regards to structural determinations of adsorbates on metal surfaces.When x rays are Bragg-reflected from a crystal, the incident and diffracted waves interfere to set up a standing wave field parallel to and having the same spatial periodicity as the reflecting planes. The exact location of the peaks of this standing wave field shift relative to the atomic scattering planes as one scans through the region of total reflectivity associated with the Bragg condition. By measuring a yield characteristic of a bulk atom or an adsorbate excited by the standing wave field, such as Auger electron emission, core level photoemission, or x-ray fluorescence, the atom's position relative to the diffraction planes can be determined.
Dynamical Lorentz TEM observation of exchange coupling in MR Ni0.80Fe0.20/NiO films
Authors: Cao Wei 
Published: June 2020

In our research program involved with materials showing magnetoresistive (MR) phenomena, attention has been given to detailed microstructural analyses in order to understand physical properties and other characteristics. One of the biggest problems in the MR sensor application is the noise associated with Barkhausen jumps due to magnetic domain wall motion in the MR sensor, usually permalloy films (Ni0.80.Fe0.20) It has neen found that when a permalloy film was deposited together with an antiferromagnetic film such as FeMn, the noise could be suppressed. It is known that there is an exchange coupling field ( He) in the Ni0.80.Fe0.20/FeMn bilayers through the interface, and it is this exchange coupling field that makes the MR sensor a single domain which suppresses the noise. However, FeMn antiferromagnetic films have poor corrosion resistance, and this provides a motivation to find a substitute material for FeMn.Antiferromagnetic NiO and CoO have received some attention as alternative materials because of their corrosion resistance.
Image processing of conventional TEM images: a catalyst case study
Authors: Briceño-Valero J. M. , Martinez L. , Moore K. , Grassian V. 
Published: June 2020

Particle characterization with the Transmission Electron Microscope (TEM) has the inherent problem of interpreting three dimensional objects from two-dimensional projections. Relevant questions when measuring small particles include how projection of the image will distort measurement of crystallite size, and how will the image distort the morphology of the particle Another difficulty is the effect of overlapping images from two or more particles. In the case of supported catalysts, an additional problem may be termed "differential contrast" which interferes with distinguishing between the supported metal crystallites and the support itself. While these situations may appear to be quite different, the is a shared concern of how the general appearance of the particle image related to its real shape. Image processing technology can be used to extract and display hidden information from conventional TEM micrographs. In this study, platinum particles supported on silica were examines.TEM images were taken at 80,000X magnification with a Hitachi H-600 at 100 kV, digitally acquired using an Imapro QCS 3200 flatbed scanner at 3200 dots per inch.
Electron diffraction of copper perfluorophthalocyanine on the HVEM
Authors: Tivol W. F. , Fryer J. R. 
Published: June 2020

The use of high-energy (1200 kV) electrons has been shown to be advantageous in the ab initio structure analysis from electron diffraction of organic compounds. Previous studies showed that ab initio analysis of copper perchlorophthalocyanine could be accomplished at accelerating voltages at or above 1000 kV, but not at 400 kV for crystals which are about 10 nm thick. Copper perbromophthalocyanine could also be analyzed ab initio at 1200 kV, but the presence of severe dynamical scattering precluded such analysis at lower voltages.Copper perfluorophthalocyanine (Cu FPC) was grown epitaxially from the vapor phase onto a clean KC1 crystal face. Electron diffraction patterns were obtained from crystals tilted at 20° and oriented so that the electron beam was parallel to the c-axis.Electron doses were kept to a minimum by the use of a 100 μm condenser aperture and a highly excited first condenser lens. A video system allows scanning the specimen to find a crystal suitable for the correct orientation of the grid by rotating it within its own plane and focusing the objective lens, all at an illumination level below that necessary to distinguish anything by eye on the HVEM's phosphor screen.
In situ REM study of indium particle evolution on InP(110) surfaces
Authors: Gajdardziska-Josifovska M. , Malay M. H. , Smith David J. 
Published: June 2020

Reflection electron microscopy (REM) has been used by several groups for in situ studies of terrace and step dynamics induced by phase transformations, film growth, and surface electromigration. Real-time viewing and video-recording of these phenomena has become possible with the use of intensified TV cameras under surface resonance diffracting conditions. Recently we captured the dynamics of nucleation and growth of In particles on InP(l10) surfaces induced by thermal annealing in an ultrahigh-vacuum transmission electron microscope. In addition to the projection problem, also encountered in TEM, the REM image interpretation is further complicated by foreshortening effects. At present, there are no developed methods for measurement of particle sizes from REM images. This work quantifies the In particle shape and size evolution from in-situ REM experiments.Samples were prepared by cleavage of an undoped (001) InP wafer along the (110) crystallographic plane. The cleavage was performed in air, immediately before loading into a Philips 430ST HREM, modified for UHV operation and equipped with a single-tilt specimen heating holder.
In situ study of tetragonal-orthorhombic structural transformation in La2-xBaxCuO4
Authors: Zhu Yimei , Tafto J. 
Published: June 2020

In the concentration range of the local Tc minimum in La2-xBaxCuO4 (0.10≤×≤0.15), below 60K, there is a low temperature tetragonal (LTT) structure (space group P42/ncm). With an increase in temperature, the structure becomes orthorhombic (LTO, space group Bmab), then above 140K becomes tetragonal (HTT) with the space group I4/mmm.The transition from HTT to LTO during cooling generates twins, and the twin morphology persists even below 60K. This is inconsistent with a pure LTT phase, since twinning is associated with an orthorhombic symmetry. To address the issue of the LTO/LTT phase transition, we performed in-situ experiments with a 200 keV TEM equipped with a liquid H2 specimen holder.Fig.1(a) and (b) show selected area diffraction patterns taken at 15K in the (001)* and (101)* zone, respectively. During in- situ cooling and the LTO/LTT transition, the (101)* diffraction pattern remains the same because h+l=2n reflections are allowed in both LTO and LTT.
Techniques for in situ HVEM mechanical deformation of nanostructured materials
Authors: Wall M.A. , Barbee T.W. , Dahmen U. 
Published: June 2020

We have developed two in situ HVEM experimental techniques which allow us to begin fundamental investigations into the mechanisms of deformation and fracture in nanostructured materials. First, a procedure for the observation of tensile deformation and failure of multilayer (ML) materials in cross-section is detailed. Second, the development of an in situ HVEM nanoindentor of surfaces and films on surfaces in cross-section is presented.Nanostructred ML materials often exhibit enhanced physical properties such as increased hardness and strength. There have been few (if any) direct observations of the mechanisms by which nano-scale structures affect deformation thereby enhancing mechanical performance. Nanoindenting has become a primary technique for measuring the mechanical properties of small volume materials. The mechanical properties of small volumes can vary greatly from bulk values. The elastic and plastic response and microstructure evolution in these small volumes under the indentor tip has never been dynamically observed before. Observation of the behavior of material under these conditions would no doubt further our understanding of the mechanical behavior of nanostructured materials.