bluuebunny/crossref_metadata_2025_split huggingface dataset:
SIMS Microarea Depth Profiling of Microelectronic Device Structures
Authors: von Criegern Rolf , Zeininger Heinz 
Published: June 2020

In recent years, considerable progress has been made in SIMS (secondary ion mass spectrometry) with respect to its ability to measure dopant depth profiles in μm2-sized areas of microelectronic devices. This progress is mainly due to the fact that for the first time two of the main requirements associated with this application are fulfilled within one instrument (the Cameca IMS 4F):. the availability of a sub-μm ion beam of a species ensuring high secondary ion yields of the dopants (in this case: negative secondary ions emitted upon cesium bombardment)and . a mass spectrometer system with high transmission (from sample to detector; in this case: about 27%).The lateral resolution (smallest spot size of the cesium beam) which we obtain with our instrument is about 0.3 μm so that indeed areas as small as 1 μm2 can be defined on a sample. The detection limit for a dopant in an analytical volume of 1 μm × 1 μm × 10 nm (10 nm = sputter depth per data point in the profile) is then determined by the secondary ion yield and the instrument transmission.
X-Ray Microprobe Analysis of Frozen Hydrated Cryosections for Study of Central and Peripheral Nervous System
Authors: Saubermann Albert J. , Castiglia Carolyn M. , Foster Margaret C. , Lagasse Robert S. , LoPachin Richard M. 
Published: June 2020

Knowledge of elemental distribution is of great importance to understanding normal and abnormal function of the nervous system. Because elements of biological interest are easily displaced using conventional preparative methods, low temperature preparative methods are necessary to preserve elemental distribution. We have applied our methods for x-ray microprobe analysis of frozen hydrated cryosections to investigations of the central and peripheral nervous system in invertebrate and vertebrate animals. We have applied these methods to several areas of neuroscience including neuroanatomy/neurochemistry neurophysiology, neuropharmacology, neurotoxicology, and neuropathology.X-ray microprobe analysis is not a substitute for electrophysiological measurements. Unfortunately there is often confusion between what is measured by the electron probe and between what is measured with microelectrodes. The information we obtain from x-ray microprobe analysis (XMPA) provides a measure of elemental mass fraction usually on the basis of dry mass, although using frozen hydrated techniques provides additional information by relating elemental mass to wet weight mass.
Why the Bloch Wave Solution for Reflection Fails on the Au(110) Surface
Authors: MA YIQUN 
Published: June 2020

The Bloch wave method has been widely used for interpreting reflection high energy electron diffraction (RHEED) patterns and the consistency between the theory and high energy electron reflection (HEER) experiments has been claimed by different authors. The recent rigorous investigation on the consistency between the Bloch wave method and the multislice approach due to Cowley and Moodie in the reflection case for Au(001) surface has also provided a clear theoretical proof for the validity of the Bloch wave method in reflection case. However, a severe deviation of the Bloch wave solution for the Au(110) surface in the reflection case from the stabilized solution of its multislicing via the multislice iteration has recently revealed by the BMCR method (Bloch wave + Multislice Combined for Reflection).Fig.1 shows the results calculated for the Au(110) surface using the BMCR method. The incident angle is 30mRad and the absorption is included by taking the imaginary potential as 10% of the real potential in both the Bloch wave and multislice calculation.
Stability of Fluorinated Organic Compounds as Measured by Parallel-Detection EELS
Authors: Ciliax B.J. , Kirk K.L. , Leapman R.D. 
Published: June 2020

The use of fluorine-labelling to localize specific organic compounds at the sub-cellular level by means of electron energy loss spectroscopy (EELS) was suggested over ten years ago. Since then, however, there have been differing reports about the susceptibility of fluorinated compounds to fluorine loss in the electron beam; damage doses appear to range over several orders of magnitude. Recent advances in EELS, i.e. the availability of parallel detectors, have generated renewed interest in this labelling technique. We therefore have undertaken a more systematic study of radiation damage in a series of aromatic and aliphatic fluorinated compounds as a function of dose and temperature.Energy loss spectra were recorded using a VG Microscopes HB501 STEM equipped with a Gatan model 666 parallel-detection spectrometer. The vacuum at the specimen was better than 5×10−9 mbar and the specimen could be cooled from room temperature to 100 K. Samples were prepared by air drying thin layers of the compounds dissolved in appropriate solvents on to ˜10 nm carbon or aluminum evaporated films supported on 200 mesh copper grids.
point-Analysis Using the Extrapolation Method in the Analytical Electron microscope
Authors: Horita Zenji , Nishimachi Ryuzo , Sano Takeshi , Nemoto Minoru 
Published: June 2020

Absorption correction is often required in quantitative x-ray microanalysis of thin specimens using the analytical electron microscope. For such correction, it is convenient to use the extrapolation method[l] because the thickness, density and mass absorption coefficient are not necessary in the method. The characteristic x-ray intensities measured for the analysis are only requirement for the absorption correction. However, to achieve extrapolation, it is imperative to obtain data points more than two at different thicknesses in the identical composition. Thus, the method encounters difficulty in analyzing a region equivalent to beam size or the specimen with uniform thickness. The purpose of this study is to modify the method so that extrapolation becomes feasible in such limited conditions. Applicability of the new form is examined by using a standard sample and then it is applied to quantification of phases in a Ni-Al-W ternary alloy.The earlier equation for the extrapolation method was formulated based on the facts that the magnitude of x-ray absorption increases with increasing thickness and that the intensity of a characteristic x-ray exhibiting negligible absorption in the specimen is used as a measure of thickness.
The effect of small additions of Cu on precipitation in Al-Mg-Si alloys
Authors: Tamizifar M. , Cliff G. , Devenish R.W. , Lorimer G.W. 
Published: June 2020

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.
Detection and Quantification Problems in the Analysis of Light Elements With UTW Detectors
Authors: L’Espérance Gilles , Botton Gianluigi , Caron Mario 
Published: June 2020

Recent developments in windowless (WL) or ultra-thin window (UTW) detectors, improved energy resolution, larger angles of collection (0.15-0.2 sterad), higher voltages (200-400 kV) make energy dispersive spectrometry more attractive for the analysis of low Z elements down to beryllium (Ref. 1 and Fig. 1). It lends itself to faster, more routine analysis and offers in many cases the possibility of carrying out qualitative analysis for a wider range of materials thickness. It has, however, generally been recognised to have lower sensitivities than EELS except for some elements in biological materials. Also, UTW analysis have been restricted to qualitative analyses, largely due to the large absorption even for relatively thin samples.This paper presents results that can typically be achieved with both SEM and TEM’s, difficulties in quantifying the data and the sensitivity that can be expected.The detectors (Link LZ-4 and Link LZ-5) on both our SEM (JEOL 840) and TEM (JEOL 2000FX) have a resolution of ≈ 134 ev at 5.9 kev and allow the detection of boron from pure B with the peak well resolved from the background and a peak/valley ration of 12.
Examination of Extra Electron Diffraction Spots Observed in Deuterium-Irradiated Silicon by Using Parallel Electron Beam Illumination
Authors: Oshima Ryuichiro , Honda Shoichiro , Tanabe Tetsuo 
Published: June 2020

In order to examine the origin of extra diffraction spots and streaks observed in selected area diffraction patterns of deuterium irradiated silicon, systematic diffraction experiments have been carried out by using parallel beam illumination.Disc specimens 3mm in diameter and 0.5mm thick were prepared from a float zone silicon single crystal(B doped, 7kΩm), and were chemically thinned in a mixed solution of nitric acid and hydrogen fluoride to make a small hole at the center for transmission electron microscopy. The pre-thinned samples were irradiated with deuterium ions at temperatures between 300-673K at 20keV to a dose of 1022ions/m2, and induced lattice defects were examined under a JEOL 200CX electron microscope operated at 160kV.No indication of formation of amorphous was obtained in the present experiments. Figure 1 shows an example of defects induced by irradiation at 300K with a dose of 2xl021ions/m2. A large number of defect clusters are seen in the micrograph.
Structure Information From Electron Diffraction Intensities
Authors: Gjønnes J. , Bøe N. , Gjønnes K. 
Published: June 2020

Structure information of high precision can be extracted from intentsity details in convergent beam patterns like the one reproduced in Fig 1. From low order reflections for small unit cell crystals,bonding charges, ionicities and atomic parameters can be derived, (Zuo, Spence and O’Keefe, 1988; Zuo, Spence and Høier 1989; Gjønnes, Matsuhata and Taftø, 1989) , but extension to larger unit cell ma seem difficult. The disks must then be reduced in order to avoid overlap calculations will become more complex and intensity features often less distinct Several avenues may be then explored: increased computational effort in order to handle the necessary many-parameter dynamical calculations; use of zone axis intensities at symmetry positions within the CBED disks, as in Figure 2 measurement of integrated intensity across K-line segments. In the last case measurable quantities which are well defined also from a theoretical viewpoint can be related to a two-beam like expression for the intensity profile:With as an effective Fourier potential equated to a gap at the dispersion surface, this intensity can be integrated across the line, with kinematical and dynamical limits proportional to and at low and high thickness respctively (Blackman, 1939).
Determination of Positional Parameters by CBED
Authors: Tanaka Michiyoshi , Tsuda Kenji 
Published: June 2020

Convergent-beam electron diffraction (CBED) has been successfully applied to the determination of symmetries of perfect crystals and of characteristics of crystal imperfections. CBED is now entering a stage of quantitative studies. Vincent et al. first demonstrated for AuGeAs a method to determine atomic positions with use of CBED patterns, in which the positional parameters were determined by fitting the intensities of higher-order Laue-zone (HOLZ) reflections calculated under the (quasi) kinematical approximation with the experimental intensities.We report a simple case of the positional parameter determination for the low temperature phase of SrTiO3. This material undergoes a second order phase transformation at 110 K from the high temperature form of Pm3m to the low temperature form of I4/mcm upon the slight rotation of the oxygen octahedra or the condensation of the R25 mode (Fig. 1). The structure analysis of the phase I4/mcm means to determine the rotation angle ϕ and the isotropic Debye-Waller factor B of the oxygen ions.
Functional information from magnetic resonance imaging
Authors: Koretsky Alan P. , e Silva Afonso Costa , Lin Yi-Jen 
Published: June 2020

Magnetic resonance imaging (MRI) has become established as an important imaging modality for the clinical management of disease. This is primarily due to the great tissue contrast inherent in magnetic resonance images of normal and diseased organs. Due to the wide availability of high field magnets and the ability to generate large and rapidly switched magnetic field gradients there is growing interest in applying high resolution MRI to obtain microscopic information. This symposium on MRI microscopy highlights new developments that are leading to increased resolution. The application of high resolution MRI to significant problems in developmental biology and cancer biology will illustrate the potential of these techniques.In combination with a growing interest in obtaining high resolution MRI there is also a growing interest in obtaining functional information from MRI. The great success of MRI in clinical applications is due to the inherent contrast obtained from different tissues leading to anatomical information.
Ionization delocalization and alchemi of B2-ordered alloys
Authors: Anderson I. M. , Bentley J. 
Published: June 2020

Recent formulations of the ALCHEMI technique have explicitly accounted for ionization delocalization of an element i with a single linear parameter Li,- that represents the extent of localization. The x-ray emission of a spectral line characteristic of the element is assumed to be proportional to a linear combination of the thickness-averaged electron intensity at (1) the site of the atom (fraction: Li) and (2) averaged over the unit cell (fraction:1 - Li)). The parameter Li is assumed to be characteristic of the elemental shell and independent of the diffracting conditions. In consequence of these assumptions, it has been shown that ionization delocalization correction can be performed in conjunction with "statistical" ALCHEMI by correcting only the extracted correlation coefficients.The parameter γiξ / Ii(0) is defined to be the ratio of the characteristic intensity (I) of element i at a crystal orientation (ξ) to its characteristic intensity at a reference orientation (0), which is ideally free of electron channeling effects.
Experimental measurement of Debye-Waller factors
Authors: Zuo J. M. , Holmestad R. , Tomokiyo Y. , Yase K. 
Published: June 2020

Effects of atomic thermal vibration in a crystal on the diffracted intensities is described by the Debye-Waller factor (DWF). In general, DWF is a 3×3 symmetric matrix with six independent elements. For isotropic atomic vibration or atoms with cubic site symmetry, a single DWF B suffices:

here s=sinθb/λ. DWFs are among the refined parameters in structure analysis in x-ray or neutron diffraction. The accuracy of DWF in such measurements often depends on the quality of the crystal. In quantitative electron diffraction, accurate DWF is needed for 1) converting Fourier coefficients of potential to that of charge density, 2) comparison with theoretical calculations of static crystals, 3) estimation of high order structure factor and absorption coefficients.DWF can be determined from measured amplitude of high order structure factors where the effects of bonding is minimal and DWF largest. Fig. 1 shows a plot of logrithmitic of ratios of measured MgO electron structure factors and calculated ones without temperature factor.
Self-assembly of surfactant-silicate nanophases
Authors: Walker S. A. , Zasadzinski J. A. 
Published: June 2020

Nanostructured zeolites are ubiquitous throughout chemistry as catalysts and sorption media' A new variety of zeolites, constructed by templating inorganic silica on surfactant liquid crystalline phases, consist of ordered arrays of cylindrical pores with diameters ranging from 20 Å to greater than 500 Å. The nanostructure of these materials can be tailored to a variety of applications, each of which makes use of the zeolite network's large surface area and prescribed microstructure. Recent studies indicate that the initial step in the nanophase formation is a cooperative self-assembly of inorganic silicate species and organic surfactant species, dictated by ionic interaction between silicate anions and cationic surfactants. Freeze-fracture transmission electron microscopy (FF-TEM) is the only technique that can visualize this self-assembly process in situ to determine phase boundaries and examine the formation mechanism.The nanophases form on mixing aqueous cetyl trimethylammonium bromide (CTAB) with silicate (SiO2; prepared from CAB-O-SIL M-5, tetramethylammonium hydroxide (TMA-OH), trimethyl benzene (TMB), methanol (CH3OH), and water).
In situ reversed deformation of aluminum single crystals in the HVEM: a new X-Y straining stage
Authors: Wall M. A. , Kassner M. E. 
Published: June 2020

The metal fatigue phenomenon is poorly understood, partially because the dislocation dynamics of reversed deformation have not been well characterized. Little success has been realized with the direct observation of dislocations during in situ cyclic deformation. Problems associated with buckling of the specimen foil occur during applied shear, bending or compression. Buckling can preclude adequate imaging conditions and further complicate the thin foil stress-state. Recent experiments have shown that dislocation movement can be reversed by tensile stressing in alternate perpendicular directions (i.e. 90° rotation of the tensile stress to X and Y directions results in the reversal of the shear stress). Buckling of the specimen foil is also reduced in these experiments.Results from recent in situ reversed deformation experiments are presented here. The experiments were performed on a new straining stage which is a modification of the Sleeswyk- Kassner X-Y stage. The specimen design and preparation procedures have also been modified to facilitate better and more reproducible in situ experiments. The new X-Y straining stage is illustrated in figure 1.
Symmetry of molecular wavefunction in BaBiO3 determined by q-resolved EELS
Authors: Wang Y.Y. , Dravid V.P. , Zhang F.C. 
Published: June 2020

Momentum-transfer (q) resolved electron energy loss spectroscopy is a unique technique to investigate the symmetry of electronic excitations in materials. Under small momentum-transfer conditions, the dielectric function derived from electron energy loss spectrum (EELS) is comparable to the dielectric function obtained by optical measurement. However, relatively large momentum-transfer conditions, which optical spectroscopy cannot achieve, can be met with high energy electrons and such q-resolved EELS data can provide dynamic information of the excitations as well as possible location of optically forbidden transitions.According to the Born approximation, the differential cross section of inelastic scattering can be written as:(1)where Ψo and Ψf are the initial- and final-state wave functions with energies as Eo and Ef, respectively, q is the momentum transfer. If rc is the effective radius of the excitation, then for q<1/rc, one can write:(2)For small q, the second term dominates the integral, permitting dipole-allowed transitions. For large q, the third term, which contains monopole and quadrupole transitions, increases in strength relative to the dipole transitions.
Observation of grain boundary segregation in advanced ceramics using high-resolution imaging SIMS
Authors: Levi-Setti R. , Soni K. K. , Chabala J. M. , Thompson A. M. 
Published: June 2020

The significance of grain boundaries in controlling processing and properties of ceramics is widely acknowledged. Through the addition of suitable dopants to ceramics, their processability and properties can be improved. These dopants may segregate to grain boundaries, but the characterization of boundary chemistry is a challenging task. Studies of segregation phenomena require the application of high-lateralresolution techniques such as STEM/AEM or surface sensitive techniques such as AES, XPS. These techniques require rigorous sample preparation and have their limitations.The scanning ion microprobe is a powerful tool that has exhibited unprecedented potential in the characterization of grain boundaries in ceramics. When interfaced to a mass spectrometer (magnetic sector in our case), this instrument allows mapping of many trace elements at nanometer level in bulk specimens. The combination of excellent sensitivity and high spatial resolution enables direct imaging of grain boundary segregants. The results thus obtained are free from artifacts that typically complicate analysis with broad beam, non-imaging techniques.
Ceramic thin-film reactions: phase boundaries and kinetics
Authors: Kotula Paul G. , Barry Carter C. 
Published: June 2020

Interfacial reactions between epitactic nickel oxide thin films and single-crystal aluminum oxide substrates were investigated as a function of substrate orientation. Two thin-film reaction geometries were employed for this purpose. The first, which was used to study the nucleation of the reaction product, consisted of epitactic nickel oxide thin films on alumina substrates. The second, which was used to determine the reaction kinetics, was similar to the first except that a thin epitactic buffer layer of the reaction product was placed between the nickel oxide film and substrate. In this case, the nucleation was avoided by essentially ‘nucleating’ the reaction product artificially. As thin films were utilized, and the scale of the salient microstructural features were correspondingly small, electron microscopy techniques were applied to determine the preferred nucleation sites and measure the rate at which the reaction proceeds for the respective geometries.Both types of thin-film reaction-couple geometry were produced by pulsed-laser deposition (PLD). PLD is a versatile thin-film deposition technique capable of producing high-quality oxide epilayers. The setup for PLD has been described elsewhere.
A TEM study of the incommensurate modulated structure in Sr2CuO3+δ
Authors: Wang Y.Y. , Zhang H. , Dravid V.P. , Marks L.D. , Han P.D. , Payne D.A. 
Published: June 2020

Hiroi et al. have recently reported the occurrence of superconductivity at a transition temperature of ~ 70 K in Sr2CuO3+δ. They observed a superstructure with lattice constants of Neutron diffraction studies on this compound by Shimakawa et al. indicate that the apical oxygen is fully occupied, whereas the oxygen in CuO2 plane is half occupied. If oxygen does not fully occupy in the conducting CuO2 planes, it raises doubts about our current understanding of superconductivity in the cuprates, which relies on full oxygen occupancy for the CuO2 planes.Recently, Han et al. observed a dependence of Tc on post annealing treatment of the high pressure synthesized Sr2CuO3+δ. They noticed that heating the sample to 300°C increased the Tc from 70 K to 94 K and that further heating to 450°C caused the sample to lose superconductivity.In order to investigate the structural and microchemical details of Sr2CuO3+δ, transmission electron diffraction, high resolution electron microscopy, and electron energy loss spectroscopy are employed.