bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural effect of the SC-AF transition in BSCYCO system
Authors: Wen Shulin , Song Chenyu , Eades J.A. 
Published: June 2020

The transition between the SC (superconductor) and the AF (antiferromagnetic semiconductor) has been investigated in the BSCYCO (Bi2Sr2Ca1-xYxCu2O8+Y) system. During the investigation a tetragonal(T)-orthorhombic(O) structural transformation accompanied by a sharp drop in Tc around at Xc=0.4 has been observed.Some of previous studies on BSCYCO revealed the transition from the SC to the AF around at x=0.5, and interpreted it as a result of a decreasing hole concentration, We have also studied the SC-AF transition of BSCYCO with analytical data combination from not only Tc measurements, but also X-ray diffraction, electron diffraction and energy dispersive spectroscopy (EDS) results. We found that a structural transformation from the tetragonal(T) to the orthorhombic(O) system would be mainly responsible for the SC-AF transition.
Flotation of Athabasca oil sands: Microscopical determination of structure of bituminous froth
Authors: Lam W.W. , Payette C. , Munoz V.A. , Mikula R.J. , Tyerman J. 
Published: June 2020

The extraction of bitumen from oil sands involves the flotation process where the initial separation of the oil phase, or the bituminous froth, from the inorganic solids and water occurs. However, the froth obtained has high solids concentration and water, which produces problems in downstream operations. Concurrently, some of the oil reports to the tailings, with economic and environmental impact.Flotation can be considered to be a physical-chemical separation process which depends on the selective adhesion of air to the desired component (bitumen) in order to separate it from the water and solids. The feed to the flotation process is an oil-in-water emulsion with relatively high solids. At some point in the separation vessel, this emulsion inverts and becomes a water-in-oil emulsion and forms the bituminous froth. Understanding this inversion process will help in maximizing water and mineral matter drainage from the bitumen product, leading to an improvement in bitumen extraction from oil sands. As well, the partitioning of solids can be understood by studying their wettability with the froth and thus determining whether or not these solids report to the tailings, or are carried upward by attachment to air bubbles in the flotation cell.
Phase changes during heat treatment of electrodeposited WO3, MoO3 and V2O5
Authors: Veilleux G. , Guerfi A. , Saint-Jacques R. G. , Dao Lê H. 
Published: June 2020

Many transition metal oxides have been studied in the last two decades. By an appropriate chemical or electrical means, ions can be inserted into the structure of these oxides with minimal structural changes. This process known as coloration can easily be reversed. This reversible mechanism is of particular interest in applications such as battery and fuel cell electrodes, chemical sensors, electrochromic displays and catalysts.In this study, films of three transition metal oxides (WO3, MoO3, V2O5) were prepared by electrodeposition. The morphology and the structure of these films were analyzed by transmission electron microscopy (TEM) in their as-deposited states and after heat treatment in ambient air up to 500°C. Previous measurements made by differential scanning calorimetry (DSC) showed exothermic peaks corresponding to phase changes. The temperature values determined at those peaks were then chosen as specific treatment temperatures.
Mounting of specimens for SEM with the common glue gun
Authors: Barish Leo 
Published: June 2020

Specimens are usually attached to SEM studs by means of either sticky tape, adhesives, or melts. The use of sticky tape is very convenient and fast; unfortunately, the bonds formed are not strong or stable. In addition, it is difficult to attach large, irregular shaped specimens with tape. Adhesives, usually solvent–based, can form strong bonds; however, for the satisfactory operation of the coater and the SEM, the solvent must be evaporated completely which can take considerable time.Melt adhesives can set up strong bonds very quickly and there is available a commercial melt adhesive mounting kit; however, the procedure for its use is cumbersome. When using this kit, the adhesive is first melted onto thin aluminum plates, which are then cooled and placed aside. When ready for the attachment of the specimen, a plate is heated to remelt or soften the adhesive; the specimen is then adhered to the surface. After cooling, the plate with the attached specimen is clamped onto a special SEM stud.
Three-dimensional organization and functional relationships of endocytotic compartments in pig intestinal epithelial cells
Authors: Heath Julian P. , Nichols Buford L. , Kömüves László G. 
Published: June 2020

The newborn pig intestine is adapted for the rapid and efficient absorption of nutrients from colostrum. In enterocytes, colostral proteins are taken up into an apical endocytotic complex of channels that transports them to target organelles or to the basal surface for release into the circulation. The apical endocytotic complex of tubules and vesicles clearly is a major intersection in the routes taken by vesicles trafficking to and from the Golgi, lysosomes, and the apical and basolateral cell surfaces.Jejunal tissues were taken from piglets suckled for up to 6 hours and prepared for electron microscopy and immunocytochemistry as previously described.
Nuclear change during differentiation of Entamoeba invadens
Authors: Morales-Vallarta M. , Mata-Cárdenas B. , Ramírez-Bon E. 
Published: June 2020

The cyst of Entamoeba histolytica is the infective phase of this parasite, but much of its differentiation process remains unknown since it is not possible its in vitro encystation. However, differentiation of E. invadens, an ameba that parasites reptiles is used as an experimental model for amebiasis research, specially in differentiation aspects, since E. invadens can be induced to in vitro encystation.The nuclear division during encystation of E. invadens has been described by some authors, but this work, has described this process through light microscopy. In the present work we report the morphologic nuclear change and the chromatin organization observed by electron microscopy.Trophozoites of E. invadens IP-1 were grown in TP-S-1 medium, and encysted in Rengpien and Bailey medium (AEM). During encystation several samples were analysed for different times. The cysts of trophozoites were washed with phosphate buffer saline, postfixed in 1% osmium tetroxide in 0.2 M phosphate buffer pH 7.2 dehydrated in ethyl alcohol and embedded in epoxi resin.
Visual limitations to image interpretation
Authors: Pelli Denis G. 
Published: June 2020

Most images are interpreted solely by visual perception. What we can perceive in an image is limited by the quality of the image (e.g. the contrasts of the signal and noise) and by intrinsic limits of our visual systems. In this abstract I will describe the intrinsic noise in the visual system. In my presentation I will also demonstrate some limits to the complexity of patterns that may be perceived.THE EQUIVALENT INPUT NOISE OF HUMAN VISIONIn order to see, we must transduce the photons entering our eye into neural activity. The absorption of light by matter is a stochastic phenomenon. The intensity of the light determines only the probability of a photon absorption by a photoreceptor. Thus vision is intrinsically noisy, based as it is on the random absorption of photons.
Convergent-beam characterization of some oxides which undergo structural phase transformations
Authors: Tanaka M. 
Published: June 2020

We have been concerned with the development of convergent-beam electron diffraction (CBED) techniques and their application to materials science. Our effort is now concentrated to identify the nature of crystal defects. Our application has been focussed on materials most of which undergo structural phase transformations: NdNbO4, La2Ti2O7, Sr2(Ta1-xNbx)2O7, Fe3O4, PbZrO3, PbZrO0-7Ti0.3O3, SrTiO3, BaPb1-xBixO3, hex.BaTiO3, Bi2.5Na0.5Nb2O9, MgAl2O4, MnSi, TaS3, NbS3+x, Mo2S3. In the present report, the results on four oxides will be reviewed.a) La2Ti2O7Gasperin determined the space group of the room temperature phase to be P21, but Scheunemann and Miüller-Buschbaum reported its space group to be Pna21. Ishizawa et al. studied the phase transformation between room temperature and 1173 K using X-ray diffraction. They determined the space group of the room temperature phase to be P21 and found the presence of twin domains.
The surface step: Its strain field and REM image contrast splitting
Authors: Peng L.-M. , Cowley J.M. , Hsu Tung 
Published: June 2020

Experimental and theoretical considerations suggest that, due to the loss of two dimensional periodicity of an infinite surface at surface steps, some sort of atomic relaxation will be expected to occur around the step . A proposed surface step model is shown in Fig.l. A surface step (Fig.1c) may be decomposed into a perfect surface step (Fig.1a) and a distortion field around the step (Fig.1b). Since the perfect surface step produces phase contrast but does not produce diffraction contrast or contribute to the step contrast splitting, only the distortion field will be considered.Shown in Fig.2 is the distortion field distribution associated with the surface step and the corresponding variation in its local incident angle. Fig.3 is the reflected intensity rocking curve around a specific Bragg angle. While the reflected beam from the undistorted surface area that is far from the step gives the background reflection intensity, the local variation in the incident angle, along with the dependence of the reflected beam intensities on the incident angle, will produce diffraction contrast in reflection.
Image simulation in scanning electron microscopy
Authors: Joy David C 
Published: June 2020

Image simulation, as a means of image interpretation, has been an important component of high resolution transmission electron microscopy for many years. By contrast scanning electron microscopists have relied almost exclusively on simple visual analogies to understand the micrographs that they produce. However with the development of SEMs capable of near atomic levels of resolution, and with the requirement for accurate dimensional metrology of sub-micron features in semiconductor devices using the SEM, a more quantitative approach to image formation and analysis is needed.Image simulation in the SEM encounters several special problems. Firstly, the signal displayed to form the micrograph is not well defined in terms of either the contrast mechanisms which give rise to it, or the energy and origin of the electrons actually collected to produce the signal.
300kv high-performance analytical TEM (H-9000)
Authors: Kobayashi H. , Sato H. , Miyauchi K. , Onai T. , Shii K. , Isakozawa S. , Kubozoe M. 
Published: June 2020

Higher voltage operation has many advantages for transmission electron microscopy.These advantages include better TEM image resolution and ease of specimen imaging. For analytical microscopy, the higher voltage operation has advantages such as higher source brightness, and better spatial resolution.We reported development of a 300kV ultra high resolution electron microscope. At this time, we would like to report an analytical type 300kV electron microscope.We have incorporated a side entry specimen stage which permits ±45° specimen tilt and is convenient for characteristic x-ray detection. We have also incorporated an analytical objective polepiece which has Cs of 2. 5mm, Cc of 2. 3mm and theoretical TEM image resolution of 0.23nm.
Low-workfunction field-emission source for high-resolution EELS
Authors: Batson P. E. 
Published: June 2020

In recent years,instrumentation for electron energy loss spectroscopy (EELS) has been steadily improved to increase energy resolution and collection efficiency. At present 0.40eV at 10mR collection half angle is available with commercial magnetic sectors (e.g. Gatan, Inc. and VG Microscopes, Ltd.), and 70meV at 10mR has been demonstrated by use of a Wien filter within a large deceleration field. When these high resolution spectrometers are coupled to the modern small electron probe instrument, we obtain a tool which promises to reveal local changes in bandstructure and bonding near defects and interfaces in heterogeneous materials.Unfortunately, typical electron sources have intrinsic energy widths which limit attainable spectroscopic resolution in the absence of some monochromation system. For instance, the W thermal emitter has a half width of about 1eV.
New Side-Entry Environmental Cell Equipment for Dynamic Observation
Authors: Fukami A. , Fukushima K. , Ishikawa A. , Ohi K. 
Published: June 2020

Since 1970, we have been developing wet cell microscopy to observe hydrated materials using film-sealed environmental cell (or hydration chamber; abbreviated as EC). Specimen stages in which the EC is set have been manufactured, four top-entry and one side-entry types, for 100 kV electron microscope in series with improvement. We have carried out in-situ observations on the behaviour of hydrated biological or non-biological materials according to the environmental changes; morphological and/or structural change caused by evacuation around the specimens after observing them in wet gas environment. chemical or biochemical reaction processes between specimens and liquid chemicals injected into the EC during observation.Based on these experiences, we manufactured a new EC holder of side-entry type and its related equipments for dynamic observation with high resolution This new holder was designed for JEM-2000EX electron microscope, whose evacuation system was modified for EC operation.
Scanning Electron Microscopy with Polarization Analysis – SEMPA
Authors: Celotta R. J. , Unguris J. , Pierce D. T. 
Published: June 2020

The advancement of magnetics science and technology requires the ability to image magnetic microstructure, i.e. domains, below the 1 micron optical resolution limit. As an alternative to Lorentz microscopy, SEMPA was proposed in 1982 after it was realized that the secondary electrons ejected from a ferromagnetic surface are spin polarized. That is, they retain both the degree and direction of polarization characteristic of the spin alignment within the ferromagnet. By replacing the secondary electron detector in a UHV SEM with a detector capable of measuring both the number and polarization of the secondary electrons, it has been possible to simultaneously image both physical and magnetic microstructure. A conceptually similar microscope has been under development by Koike et alSEMPA depends on the availability of a efficient way to measure the spin polarization of a free electron beam. Traditionally, Mott scattering has been used. Mott detection is based on the small spatial asymmetry that occurs when electrons are scattered from a high-Z material at 120KeV.
MgO Passivation of Vanadium on Cracking Catalyst
Authors: Hall J. B. , Hirschherg E. H. 
Published: June 2020

Vanadium, which is present in crude oil as metal porphyrins, builds up on cracking catalyst during use and is believed to cause decomposition of the faujasite component. The addition of magnesia (MgO) to cracking catalyst is thought to passivate the vanadium thereby prolonging catalyst life. An analytical electron microscope (AEM) investigation was undertaken to gain an understanding of the passivation mechanism.The base catalyst used in this study was composed of faujasite and an amorphous silica-alumina. Test samples were prepared by mixing steamed cracking catalyst with MgO, impregnating the mixture with vanadium and nickel naphthenates, drying at 250°F, calcining at 1000°F, and steaming at 1400°F. The two samples used for the AEM study each had final compositions of 1000 ppm Ni and 3000 ppm V, but contained levels of 30 and 3% MgO.
A tem study of amorphization in Niti irradiated with Ni2+ ions at room temperature
Authors: Maziasz P. J. , Packan N. H. , Pedraza D. F. , Lee E. H. 
Published: June 2020

Irradiation of a crystalline solid solution can cause the decomposition of the matrix into enhanced, modified thermal, or irradiation-induced precipitate phases. Irradiation can also transform the matrix into a new crystalline phase. Alternatively, the heavily irradiated matrix can become amorphous. Alloys of NiTi are intermetallic compounds with shape-memory applications whose amorphization is of both technological and basic scientific interest. Our purpose is to observe some details of the intermediate stages of amorphization to provide further insight into the mechanisms of the phenomenon.An alloy of 50.5 at.% Ni/49.5% Ti was obtained from Raychem Co. as 0.76-mm- thick sheet and then rolled to 0.5 mm sheet. Disks 3 mm in diameter were punched and annealed for 0.5 h at 850°C. This results in an ordered austenitic (B2) structure, which partially transforms to martensite after air quenching.
Liquid-Phase reaction zones in wurtzite SiC alloys
Authors: Carpenter R. W. , Braue W. , Cutler R.A. 
Published: June 2020

A relatively new method for densification of SiC compacts to produce high strength structural ceramics involves solid solution formation between wurtzite structure type α(2H)SiC and Al2OC or AIN. The solid solutions have the wurtzite structure and extend from 2 to 100 mol. % of the Al compounds. It is also known that Al2O3, and Al4C3 form a eutectic near 2150K. In the present work analytical methods were used to examine the solid/liquid reaction path followed by a powder compact of compositionxSiC+y(Al2O3+A14C3)= xSiC.3yAl2OC,where x=l and y=0.02, heat treated in nitrogen atmosphere near the eutectic temperature. At equilibrium one would expect complete solid solution of the Al2OC in SiC. For shorter times, as in the present case, a multiphase microstructure is to be expected.
Transmission Electron Microscopy studies in deformed GaxIn1-xAs
Authors: Rai R. S. , Faber K. T. , Guruswamy S. , Hirth J. P. 
Published: June 2020

The control of dislocation density during the growth of GaAs and related compounds is highly desirable for obtaining improved performance and reliability of opto-electronic devices. Doping of single crystal GaAs grown by the LEC process with Indium has been known to reduce the dislocation density significantly. Substitutional solid-solution strengthening of GaAs as an InAs, unit has been suggested to be responsible for reduction of dislocation density. To understand the mechanism involved in dislocation density reduction, deformation tests have been performed on [001] oriented Gax In1-xAs single crystals in the temperature range 700-1100°C and this paper reports some results of the TEM characterization of dislocations in these deformed single crystals.Specimens of GaAs and Ga0.99In0.01As For TEM observations were made by cutting thin slices in a desired orientation, followed by mechanical polishing and ion-milling. These specimens were examined in a JEOL JEM 200CX transmission electron microscope at 200KeV equipped with a double-tilt goniometer stage.
Effects of substrate quality and annealing on defect structures at GaAs/Si interfaces
Authors: Tsai H. L. , Lee J. W. 
Published: June 2020

Growth of GaAs on Si using epitaxial techniques has been receiving considerable attention for its potential application in device fabrication. However, because of the 4% lattice misfit between GaAs and Si, defect generation at the GaAs/Si interface and its propagation to the top portion of the GaAs film occur during the growth process. The performance of a device fabricated in the GaAs-on-Si film can be degraded because of the presence of these defects. This paper describes a HREM study of the effects of both the substrate surface quality and postannealing on the defect propagation and elimination.The silicon substrates used for this work were 3-4 degrees off [100] orientation. GaAs was grown on the silicon substrate by molecular beam epitaxy (MBE).
Study of dislocation loops in Arsenic-Rich as-grown GaAs
Authors: Lee Byung-Teak 
Published: June 2020

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.
A magnetic super lattice
Authors: Bentzon M.D. , Wonterghem J. v. , Thölén A. 
Published: June 2020

We report on the oxidation of a magnetic fluid. The oxidation results in magnetic super lattice crystals. The “atoms” are hematite (α-Fe2O3) particles with a diameter ø = 6.9 nm and they are covered with a 1-2 nm thick layer of surfactant molecules.Magnetic fluids are homogeneous suspensions of small magnetic particles in a carrier liquid. To prevent agglomeration, the particles are coated with surfactant molecules. The magnetic fluid studied in this work was produced by thermal decomposition of Fe(CO)5 in Declin (carrier liquid) in the presence of oleic acid (surfactant). The magnetic particles consist of an amorphous iron-carbon alloy. For TEM investigation a droplet of the fluid was added to benzine and a carbon film on a copper net was immersed. When exposed to air the sample starts burning. The oxidation and electron irradiation transform the magnetic particles into hematite (α-Fe2O3) particles with a median diameter ø = 6.9 nm.
A Modulated quasi-crystalline structure in an Ai-Li-Cu-Mg-Zr alloy
Authors: Zhang J. P. , Ye H. Q. , Kuo K. H. , Jiang Z. Z. , Marks L. D. 
Published: June 2020

Sainfort et. al. have observed a quasi-crystalline phase in normal equilibrium precipitates in Al-Li-Cu and Al-Li-Cu-Mg alloys produced by classical casting rather than rapid solidification. Hence the intergrowth of the icosahedral phase (I-phase) and the related crystalline structures and formation mechanism is a subject of some interest. By means of electron microscopy we have studied the I-phase precipitates extracted from an Al-Li-Cu-Mg-Zr alloy.The presence of I-phase was verified by selected area diffraction patterns shown in Fig. 1, showing the typical 5-fold and 3-fold symmetry of the point group 3 m 5, instead of ordinary translation symmetry, in (a) and (b) respectively. Fig. 2 is a high resolution image in a 2-fold axis of I-phase with the corresponding EM pattern inserted. The configuration of Fig. 2 shows not only the quasi-per iodic arrangement, but also a modulation in two directions perpendicular to this axis.