bluuebunny/crossref_metadata_2025_split huggingface dataset:
New frontiers in multispectral chemical imaging
Authors: Schaeberle Michael D. , Treado Patrick J. 
Published: June 2020

Recent advancements in visible and near-infrared multichannel detectors as well as the availability of novel imaging quality tunable filters make multispectral chemical imaging microscopy viable for routine materials characterization. Our research involves the development and application of chemical imaging methods that are rapid, non-invasive, and intuitive. The methods require limited sample preparation, and can be performed at high spectral and spatial resolution.The chemical imaging techniques employ Raman scattering, fluorescence emission or infrared absorption spectroscopies in combination with optical microscopy. In general, the methods provide qualitative and quantitative information about the composition and distribution of constituents within a wide host of materials, including biological tissues, polymers, and semiconductors.Silicon charge-coupled device (CCD) detectors are widely utilized for image detection in visible microscopy. Currently underutilized, but providing significant capabilities for chemical imaging based on infrared vibrational absorption are focal plane array (FPA) detectors providing sensitivity in the near-infrared and mid infrared. These include cameras constructed from indium antimonide (InSb), platinum silicide (PtSi), indium gallium arsenide (InGaAs) and mercury cadmium telluride (MCT).
Immunocytochemical localization of lactase in the brush border, Golgi complex and endocytotic granules of pig jejunal enterocytes
Authors: Heath Julian P. , Harrell Rhonda G. , Kömüves László G. 
Published: June 2020

We have used immunofluorescence light microscopy (IFLM) and immunogold electron microscopy (IEM) to study the distribution of lactase phlorizin hydrolase, a developmentally regulated brush border enzyme, in the enterocytes of suckling neonatal piglets. Tissues were collected from the jejunum and fixed in 4% paraformaldehyde. Cryosections were incubated in mouse monoclonal anti-pig lactase antibody (PBB 3/7/3/2, from Dr. A. Quaroni, Cornell Univ.) followed by either FITC- or 10 nm gold-conjugated anti-mouse IgG. IFLM and IEM images were digitally acquired from video and processed.Jejunal villus enterocytes of non-suckled piglets possess an apical endocytic complex and a sub-nuclear Golgi complex (Fig. 1). In the jejunal crypts, differentiating enterocytes possess an immature brush border and a supra-nuclear Golgi complex (Fig. 2). In suckled animals, absorption of colostral proteins by villus enterocytes results in the formation of dense apical and basal granules (Fig. 3); crypt cells do not accumulate granules. Many of the granules are juxtaposed to the Golgi complex (Fig. 4).
Demonstration of ultra-high-resolution soft x-ray tomography using a scanning transmission x-ray microscope
Authors: Haddad W. S. , McNulty I. , Trebes J. E. , Anderson E. H. , Yang L. , Brase J. M. 
Published: June 2020

X-ray microscopy has been an active area of research for many years, but it is now beginning to emerge as a viable imaging tool for microbiologists and materials scientists. Several groups have developed x-ray microscopes of various types using synchrotron sources laser plasma sources, and x-ray lasers. The most productive systems have been the scanning transmission x-ray microscopes (STXM). Near diffraction limited performance can be achieved with such instruments. There are however no x-ray optics having sufficiently high numerical aperture (NA) to achieve resolution in depth that is comparable with the transverse resolution. Currently the best x-ray zone plates have a NA < 0.1 for radiation in the water window. The ratio of depth resolution to transverse resolution ∂l\∂t ≈ 2/NA > 20 for present state-of-the-art zone plates.In order to improve the depth resolution, it is necessary to effectively increase the NA of the imaging system. This can be done by recording several views of the object over a large angular range. If each of the views is taken with low NA optics such that the longitudinal extent of the object is less than the depth resolution of the imaging system, then each view will be a 2-D projection of the object.
Microscopic study of Forcipomyia whitcombe ovary
Authors: Ba-Omar Taher A. , Devera David 
Published: June 2020

We have been investigating the structure of the Forcipomyia whitcombe (Diplera: Ceratopogonidae) ovary. The F. Whitcombe are biting midges which are one of the newly discovered species of Diptera: Ceratopogonidae found in Oman. They are found in bushland and grassland of the mountain of Dhofar (southern part of the Sultanate of Oman); Jabal Oara and Jabal Qamar. These midges are associated with the monsoon which hits that part of Oman during the summer months (end of June - mid September).Specimens were collecled using nets and fix directly in 70% alcohol. Some specimens were processed for light microscopy (LM) using routine histological technique and stained with H&E. Others were processed for scanning electron microscopy (SEM); dehydrated in acetone, dried in a critical point dryer (CPD). They were then cut into halves in which the lower half was coaled with gold and then examined with Jeol SEM.The body of the insect measures about 1.3 mm in length. The study showed that this insect possesses paired ovaries. Next to the ovaries there is the spermatheca (sperm storage). Each ovary contains several ovarioles polytrophic type. Each ovariole possesses several eggs which are enclosed in a layer of follicular cells (supporting and nourishing cells).
Ultra-high resolution SEMI-in-lens type FE-SEM, JSM-6320F, with strong magnetic-field lens with built-in secondary-electron detector
Authors: Miyokawa T. , Kazumori H. , Nakagawa S. , Nielsen C. 
Published: June 2020

We have developed a strongly excited objective lens with a built-in secondary electron detector to provide ultra-high resolution images with high quality at low to medium accelerating voltages. The JSM-6320F is a scanning electron microscope (FE-SEM) equipped with this lens and an incident beam divergence angle control lens (ACL).The objective lens is so strongly excited as to have peak axial Magnetic flux density near the specimen surface (Fig. 1). Since the speciien is located below the objective lens, a large speciien can be accomodated. The working distance (WD) with respect to the accelerating voltage is limited due to the magnetic saturation of the lens (Fig.2). The aberrations of this lens are much smaller than those of a conventional one. The spherical aberration coefficient (Cs) is approximately 1/20 and the chromatic aberration coefficient (Cc) is 1/10. for accelerating voltages below 5kV. At the medium range of accelerating voltages (5∼15kV). Cs is 1/10 and Cc is 1/7. Typical values are Cs-1.lmm. Cc=l. 5mm at WD=2mm. and Cs=3.lmm. Cc=2.9 mm at WD=5mm. This makes the lens ideal for taking ultra-high resolution images at low to medium accelerating voltages.
Automatic alignment of stereo images
Authors: Haselgrove John , Fodor Lou , Peachey Lee 
Published: June 2020

Stereoscopic pairs of electron microscope images are used for quantitative 3D information. A prerequisite for the measurement is to position the two images correctly relative to each other and with the stereo rotation axis of each image aligned vertically for viewing. Although this alignment procedure is relatively straightforward to perform using prints of the images, it is not straightforwardto do once the images have been digitized directly from the microscope. We have developed an algorithm for determining the parameters needed for orienting digitized images. Four parameters are needed: The displacements Δx and Δy by which one of the images must be translated to be superimposed on the other, and the angles Θ1 and Θr by which the left and right images must be rotated to bring the stereo-rotation axis vertical.The microscopist first uses an interactive routine to identify the coordinates xl(i),yl(i) and xr(i),yr(i) of a number (N) of fiducial points which can easily be recognized on each image.
Cryo imaging using an energy-filtering TEM (EFTEM): Optimum use of phase-contrast transfer function (PCTF)
Authors: Probst W. , Zellmann E. , Benner G. , Weimer E. 
Published: June 2020

Lack of contrast is one of the numerous problems arising from imaging of vitrified biological macromolecules in a TEM. This is due to the similar density of biological material and of vitreous ice and to the high background of inelastic scattering in the ice which is about four times that of carbon.Consequently in a CTEM images have to be recorded 1-3 μm underfocus to maximise phase contrast which in the same sense decreases the reliability of density information.Elastic filtering using an (EFTEM) allows closer to focus imaging still achieving considerable contrast. For 3D reconstruction of molecular densities the largest source of error is likely to arise from contributions of the PCTF. Thus, such images have to be corrected for the PCTF, which is much morereliably done for elastically filtered images close to focus.Thin vitreous ice films containing the virus particles were prepared on holey carbon grids and examined with cryo EM procedures. Images of frozen-hydrated cucumber mosaic virus (CCMV) particles ( Ø of roughly 25 nm) were recorded in Elastic Brightfield mode using the Zeiss EM 912 OMEGA with integrated imaging spectrometer and Koehler Illumination. Magnification was 50.000x, HT 120 kV, energy width 7 eV, total dose 800 electrons /nm2.
Grown-in defects in CVD α-Si3N4
Authors: Zhou D. S. , Mitchell T. E. 
Published: June 2020

Silicon nitride has been extensively studied due to its promising mechanical properties at high temperature. There are three ways to form bulk materials, namely, reaction-sintering, hot isothermal pressing, and chemical vapor deposition (CVD), among which only CVD method can produce large single crystal regions enabling determination of some fundamental physical and mechanical properties..α-Si3N4 is trigonal, P31c, with lattice parameters a=0.782 nm and c=0.559 nm. Crystals were grown by Praxair Coating Technology. The CVD process was performed with HSiCl3, NH3 and H2 gases reacted at 1500°C and at a pressure of 0.5 torr. Generally, there are two types of crystals, one with the hexagonal prismatic needle pointing in the [0001] direction; the other with a needle growth direction of [100], For the present study, the [100] crystals were used. Grown-in defects in the polycrystal regions were investigated using polarized light microscopy and transmission electron microscopy (TEM). TEM specimens were prepared bv standard techniques through cutting, grinding, dimpling and ion milling. A Philips CM30 TEM was used operating at 300 kV.
A new route for the interpretationof reconstructed wavefunctions in HRTEM
Authors: Op de Beeck M. , Van Dyck D. , Coene W. 
Published: June 2020

During the last years the renewed interest in focus variation wavefunction reconstruction algorithms has lead to a spectacular improvement of the obtainable resolution in FEG-HRTEM. Unfortunately, it was found that only for thin specimens the reconstructed wavefunction is directly interpretable in terms of the projected atomic potential. Hence there is a need for a direct structure reconstruction algorithm, starting from the reconstructed electron wavefunction. Here we propose a new channelling method in real space that only relies on the very basic concepts of dynamical diffraction in zone axis orientation, and which is very suitable to reveal the correspondence between the wavefunction and the column structure. In this way, a parametrised analytical expression can be obtained so as to reconstruct the projected structure of the object, requiring minimal prior knowledge.In order to develop a sensible structure reconstruction method, a good understanding of the multiple dynamical diffraction process is required.
The structure of zeolite LZ-277
Authors: Bateman C. A. , Kirchner R. M. 
Published: June 2020

LZ-277 is a new aluminosilicate molecular sieve. It has an x-ray diffraction (XRD) pattern nearly identical to zeolite phi but with a much smaller pore size. Whether LZ-277 and phi-like materials are intergrowths or a physical mixture of phases has been a matter of debate. The ability to determine the structure of complex zeolites has been enhanced by HREM and, more recently, by the ability to simulate XRD patterns of faulted materials. In this study, the structure of zeolite LZ-277 is reported and confirmed by simulating the XRD pattern of this highly faulted material.The low magnification micrograph shows the faulted and intergrown disc morphology typical of this material (Figure 1). The faulting is most typically twinning on (001), and is shown in the [010] diffraction pattern (Figure 2). The pattern is indexed on an a = 1.38 nm, c = 1.50 nm unit cell and both lattice parameters and systematic absences are consistent with chabazite in space group Rm.
Detection of internal Pt clusters in zeolite FAU using serial sectioning with diamond-knife ultramicrotomy and HRTEM
Authors: Bovin J.-O. , Alfredsson V. , Karlsson G. , Blum Z. , Terasaki O. 
Published: June 2020

Zeolite Y or X (FAU) has a very open framework structure with 13 Å diameter cages. Small metal clusters fit well in such cages. In catalytic research it is essential to localize the metal clusters; are they in the zeolite cavities or on the zeolite surface? In this study we will describe a method, using high resolution transmission electron microscopy (HRTEM) imaging of ultrathin sections, that give evidence that platinum is located within the zeolite. It will be shown that clusters preferably aggregate in the larger cages of the frequently occurring {111}-twin planes (TP).
Zeolite NaY (Si/Al=2.8) crystals were ion exchanged with Pt(NH3)4 Cl2 according to standard literature procedures. After ion exchange the specimen was oxidized in O2 at 383 K for three hours and finally reduced in H2 at 298 K for two hours.The zeolite crystals were embedded in epoxy resin (Spurr) for preparation of ultrathin sections. The composition of the resin was 15.0 g vinylcyclohexene dioxide (ERL 4206), 6.0 g polypropylene glycol diglycidyl ether (DER 736), 39.0 g nonenyl succinic anhydride (NSA), and 0.3 g dimethylamino ethanol (S-l).
An HRTEM study of grain boundaries in long-chain Te crystals
Authors: Isshiki Toshiyuki , Michiyuki Toshiya , Saijo Hiroshi , Shiojiri Makoto 
Published: June 2020

A Te crystal is an aggregate of spiral chains arranged about the c-axis of the hexagonal cell, and hence exhibits the growth and morphology characteristic of the long chain molecules. This paper describes the structure of grain boundaries induced during the crystal growth. Te films of a thckness of t=18 nm, vacuum deposited onto glass substrates at 120”C, were observed with a JEM 200-CX electron microscope (Cs=1.2 mm).Fig. 1a shows an HRTEM image of a grain boundary along with edge dislocations in a Te crystal. The projection of Te chains is schematically shown in Fig. 1b. Figs. 1c and 1d show enlarged images of the area enclosed by a rectangle in Fig. 1a, taken at Δf=15 and 85 nm. Each side of the boundary is either R-(p3121) or L-(p3221) crystal having the α-axis approximately parallel to the incident electron beam. Thus, there are eight possible orientations between the two grains, as shown in Table 1.
Spatial resolution measurements of electron backscatter diffraction patterns (EBSPs) in the scanning electron microscope
Authors: Hjelen Jarle , Nes Erik 
Published: June 2020

In the EBSP method the stationary electron beam hits a highly tilted bulk specimen in the SEM. The backscattered Bragg diffracted electrons form the Kikuchi line pattern on a phosphor screen. Since the first EBSP experiments were carried out in 1973, this technique has been further developed to determine crystal orientations in connection with texture development in aluminium. Using the EBSP method to calculate local lattice curvatures in heavily deformed aluminium, the spatial resolution has to be better than the selected area channeling pattern (SACP) method.The EBSP resolution (d) was measured by moving the electron beam digitally across grain boundaries in an aluminium sample. The resolution was defined to be the overlapping distance between two diffraction patterns.
Defect fine Structures as observed by in situ experiments
Authors: Saka H. 
Published: June 2020

An in-situ experiment in an electron microscope is now a well established and useful technique in materials science. In this review recent contributions of in-situ experiments, especially of straining and heating experiments, to materials science will be high-lighted.The earlier works have been reviewed by Saka and Imura.It is believed that an external stress gives rise to an anistropy in the rate at which point defects are absorbed by edge dislocations; this mechanism is considered to explain the irradiation creep. A combined in situ tensile/irradiation experiment in a HVEM has been carried out to study effects of applied stress on the growth of dislocation loops. Fig. 1 shows typical microstructures of Ag irradiated at 403K for 10 min with 1MV electrons in the absence (a), and in the presence of an external stress of 5.5 kg/mm2 (b). Frank loops of interstial type, formed by electron irradiation, grew more rapidly in the direction of the external tensile stress than in the others. These results show that an external tensile stress has a profound effect on climb rates of Frank loops of interstitial type. However, detailed analysis of the results indicates that there is a considerable discrepancy between experiment and theory.
Arrangement of molecules at lattice defect in an organic crystal
Authors: Maeda Takashi , Isoda Seiji , Kobayashi Takashi 
Published: June 2020

Many important properties of organic crystals are known to be controlled by a small amount of impurities and lattice imperfections. We have reported the molecular arrangements at defects in some metal complxes which are composed of elements such as N,O and metal in addition to C and H. The lattice energy or defect energy calculation of these materials could not be carried out with sufficient accuracy, because of the existence of such hetero atoms. In this paper we show defect structures found in epitaxial films of a simple hydrocarbon, quarterylene(Fig.1), which contains no hetero atoms and their structure was partly studied. Quarterylene purified by sublimation in a stream of nitorogen gas was deposited on a cleaved (001) surface of several kinds of alkali-halides in a vacuum of 5x10-5 Pa. The substrates cleaved in air were preheated for two hours in the vacuum and were colled at a desined temperature. The film thickness was controlled to be about lOnm.At the substrate temperatures lower than 170°C, the quarterylene film is composed of long fibrous crystals, whose long axes are parallel to two perpendicular directions in the substrate surfaces. At higher temperatures than 170°C, planar continuous crystals grow together with some fibrous ones as shown in Fig.2.
Non-equilibrium phase formation
Authors: Fujita Hiroshi 
Published: June 2020

The most important advantage of EM’s is in situ experiments on detailed processes of the same phenomena that occur in bulk materials. In recent years, in situ experiments with HVEM’s, in particular with a 3MV ultra-HVEM , has made it possible to create non-equilibrium phases, which do not exist in nature, or to control and design materials on an atomic scale. Namely, HVEM’s have developed to “Micro-Laboratory”, in which various material-treatments can be done, for natural science from powerful tools for characterization and/or identification of materials.l.The General Rule for Solid Amorphization
The author and his cowerkers have succeeded in making amorphous solids of intermetallic compounds by high energy electron irradiation. Using the electron irradiation effect, necessary conditions for the formation of both non-equilibrium phases and extremly supersaturated solid structures[3,4] can be easily and precisely controlled.
A new system for in-situ observation of dynamic process of structural and chemical changes during dual ion beam irradiation in a 400 Kv Electron Microscope
Authors: Furuno Shigemi , Hojou Kiichi , Otsu Hitoshu , Izui Kazuhiko , Sasaki Teikichi , Tsukamoto Tetsuo , Hata Takao 
Published: June 2020

In order to simulate radiation damage of fusion reactor materials, we have developed an in-situ observation system in 1986, which consisted of an electron microscope of JEM-100C type combined with a 10 keV ion gun and parallel EELS. Using this system, we have observed dynamic processes of structural and chemical changes of materials during ion irradiation. In this paper, we have developed a new in-situ observation system, with which it is possible to observe dynamic process of structural and chemical changes of materials during dual ion beam irradiation.This system consists of an analytical electron microscope of 4000FX type linked with two 40 keV ion beam accelerators, as shown in fig. 1. The maximum possible ion current on the specimen is 50μA/cm2 for 40keV He ion. Ion beams emmitted from duo-plasmatron ion guns are deflected downward by an angle of 30° with selecting magnet and are introduced into the specimen chamber. Ion beams are deflected downward again by an angle of 30° with electrostatic plism and are incident finally at an angle of 60° with the surface of the specimen, as shown in fig. 2. The images of electron microscope during irradiation are recorded with a VTR through a TV camera. It is possible to control the temperature of the specimen during irradiation within the range from 10 K to 1575 K by using both low and high temperature specimen holders. Test of tension for the specimen under irradiation is also possible. The in-situ chemical analysis in the region of 10 nm under irradiation is possible with EDS (UTW type, Tracor Nothern) and parallel EELS (666 type, Gatan). A quadrapole mass spectrometer is attached near specimen chamber to carry out TDS analysis.
HRTEM observations of schottky barrier interfaces at WSi0.4/GaAs contacts
Authors: Mitwalsky A. , Willer J. , Oppolzer H. 
Published: June 2020

WSix is one of the most favored Schottky gate metallizations due to its self-aligned contact formation capability and high temperature resistance (∽800°C) for x ∽ 0.45. It will be demonstrated that fine details of the microstructure at this WSi0.4/GaAs Schottky interface change clearly when temperature is increased up to 800°C. These findings are relevant for explaining Schottky barrier measurements usually implying the existence of an intimate and uniform contact between metallization and semiconductor. Similar investigations have been performed on related WSix (x = 0.1 and 0.6) systems.The WSi0.4 Schottky contact was sputtered from a planar magnetron compound target at a power level of 4 W·cm−2 and a deposition rate of 45 nm·min−1. As described previously films were deposited in dc-mode with an rf-bias of 50 V. Initial wafer surface preparation of bulk doped GaAs (Si : 7·1016cm−3) involved standard H2SO4 etch followed by a surface etch in diluted NH4OH. The sputtering chamber was evacuated to a base pressure of 2·10−7 Torr. A heat treatment at 250°C for 10 min of the substrate was performed immediately prior to silicide deposition. The temperature stability and interface structure of this metallization was investigated by cross-sectional transmission electron microscopy (TEM) at specimens annealed for 20 min at 400°C, 720°C and 800°C, respectively. In particular, atomic scale information was attained by high-resolution TEM (HRTEM) using a 400 kV TEM with a point resolution of 0·18 nm.