bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons
Authors: Bendersky L. A. , Boettinger W. J. 
Published: June 2020

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.
A SEM/TEM Investigation of a Polymer Membrane
Authors: Voegele-Kliewer C. E. 
Published: June 2020

INTRODUCTION. Polymeric membranes are being developed for a number of technologically important separation processes. Thus a basic understanding of their microstructure has become vital not only in the development of membranes more suitable to current requirements but also in the formation of polymers for future applications. This investigation describes the electron microscopy techniques used to characterize microstructural features which correlate with membrane separation processes.EXPERIMENTAL. An experimental membrane was examined using both a CAMSCAN SERIES IV SEM and a JEOL 1200EX STEM. The material was prepared for SEM examination using conventional freeze fracturing techniques. A low accelerating voltage, 20kV, was used to reduce the possibility of beam damage in the SEM. The membrane was prepared for examination in the TEM by using a technique described by L. Sawyer.
Particle Contents of Human Lungs
Authors: Stettler L.E. , Platek S.F. , Groth D.H. , Green F.H.Y. , Vallyathan V. 
Published: June 2020

Scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) have been used by numerous investigators to study the particle content of human lungs. Most of this work has been performed on lung specimens from subjects with known or suspected lung diseases. The object of these analyses has been an attempt to relate the composition and concentration of the particles present in the lungs to the lung disease. A major factor missing from past microanalysis work has been data from typical “normal” lungs with which the analyses of diseased lungs could be compared. Currently in progress at NIOSH, is a study in which the particle contents of 96 urban lungs from the Cincinnati, Ohio area are being determined.Preliminary results for thirty-five of these lung samples will be presented and discussed in the report. When completed, the analysis data will serve as background or baseline data for typical urban lungs with which comparisons of the particle contents of diseased lungs can be made.
Functions Of TEM Incorporated With Personal Computer and Frame Memory
Authors: Nomura S. , Isakozawa S. , Kamimura S. 
Published: June 2020

It is expected that a computer aided TEM which incorporates a frame memory system and a TV camera, provides many useful functions which have not yet been made available. We constructed an experimental TEM, shown in Fig. 1, and made some experiments which are described below.Dual Magnification Display of Specimen Images; If low and high magnification images are displayed at the same time, field selection would be a lot easier. This method has been already established in SEM. In our TEM, this is performed by memorizing the low magnification image in a frame memory, and by controlling the specimen stage by a computer. The CRT displays the low magnification image stored in the memory and a mask which indicates the specimen image area under the high magnification condition. The operator moves the mask and sets it on the area of interest. Then electron microscope magnification is changes from low to high. The stage is moved automatically, corresponding to a new masked position. We see a high magnification image on the fluorescent screen and also on the other CRT. The low magnification image stored in the memory is not changed, and the next specimen area for high magnification is readily chosen by moving the mask.
Microstructural Study of Diamond Deformed Under High Pressure and Temperature
Authors: Koch E. F. 
Published: June 2020

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.
A Practical Method of Determining Grain Boundary Crystallographic Parameters Using Microdiffraction
Authors: Randle Valerie , Ralph Brian 
Published: June 2020

To relate the observed structures in grain boundaries to the theoretical models requires a knowledge of the main parameters describing the crystallography across the boundary (e.g. 1). A number of methods have been described for determining the axis/angle of misorientation, ℓ/Θ and the plane of the boundary using conventional electron diffraction SADP (e.g. 2-3). In a recent study a distinction between the migration characteristics of special and general boundaries was made (4). A precise determination of the boundary parameters requires the manipulation of data from Kikuchi patterns (e.g. 3) and, in SADP these are only excited from thicker portions of the foil.Microdiffraction has a number of significant advantages for such studies (e.g. 5) as demonstrated here. The results come from a major investigation of the interaction between precipitate dispersions and grain boundaries (6). The alloy chosen is Nimonic PE 16 (the heat treatments are given in the figure captions). Figure 1 is a bright field image of a low angle grain boundary pinned by carbide particles.
Observations of Precipitates In 95PB-5SN Solder
Authors: Frear Darrel , Morris J. W. 
Published: June 2020

The electronic packaging of integrated circuit chips has been cited as the limiting factor in the performance and reliability of high speed data processing units. A very important part of the package is in the first level where solder bonds the IC chip to a ceramic carrier. The most commonly used first level solder is 95Pb-5Sn. The importance of this solder connection instigated the following fundamental study of the microstructure of 95Pb-5Sn and its precipitates.The alloy was melted in vacuum at 400°C using 99.9% pure Pb and Sn. The ingot was allowed to cool and age for a few days at room temperature. TEM 3mm foils were cut and mechanically thinned down to 4 mil thickness. After aging at room temperature the solder is considered to be in its equilibrium state, no further changes in microstructure are observed.
Electron Energy Loss Spectroscopy at 5Å Spatial Resolution
Authors: Isaacson M. , Scheinfein M. 
Published: June 2020

One of the ultimate goals of electron energy loss spectroscopy within the electron microscope is to be able to obtain the electronic structure of interfaces at near atomic resolution. Though this goal has not yet been achieved, there has been considerable effort devoted to elemental composition at high spatial resolution using ELS (eg. References 1-3). In this paper we wish to present initial measurements made across different types of interfaces that show core and valence shell electron energy loss spectra changing within an 8Å spatial scale across the interface.All the measurements have been performed using a modified dedicated STEM (VG Scientific HB-5) equipped with beam blanking facilities, digital control and a wide-gap aberration connected energy loss spectrometer. The details of this instrument have been described elsewhere (4). The main point to be noted is that the incident illumination half angle was 7.5mrad for these experiments and the full width at half maximum of the probe was 4.6Å (measured). With these optical conditions, 90% of all the incident beam current is contained within a diameter of 9.0Å (5). For beam sensitive materials, the recording dose was kept to less than 1/3 the dose for observable sample degradation.
Excited State Lifetime Measurement By EEL-CL Coincidence
Authors: Ahn C.C. , Krivanek O.L. 
Published: June 2020

The lifetime of an excited state can be measured by detecting both the excitation (by EELS) and the de-excitation (by catho- doluminescence), and measuring the delay between the two events. We have adapted this technique for the measurement of lifetimes in an electron microscope.The experimental set-up is shown in Fig. 1. The arrival time and the energy loss of single electrons is monitored by the EELS (Gatan 607), and the arrival time and wavelength of single photons is monitored by the CL spectrometer. Pulses corresponding to the two events are fed to a time-to-amplitude converter (TAC), which outputs a variable height pulse proportional to the delay between the events. If no second (stop) pulse is detected within a preset time interval, the TAC recognizes a “false start”, does not output anything, and starts looking for a “start” pulse again. Since the count rate in the CL channel was typically 10 to 100 times weaker than in the EEL channel, we minimized the false starts by using the CL signal as the start pulse and the EEL signal, suitably delayed, as the stop pulse. This yields a “reversed time” spectrum, but minimizes the dead time of the electronics.
Three-Dimensional Immunoelectron Microscopy of Yeast Cells by a New High-Resolution Replica Method
Authors: T. Hirano , Yamaguchi M. , Hayashi M. , Sekiguchi Y. , Tanaka A. 
Published: June 2020

A plasma polymerization film replica method is a new high resolution replica technique devised by Tanaka et al. in 1978. It has been developed for investigation of the three dimensional ultrastructure in biological or nonbiological specimens with the transmission electron microscope. This method is based on direct observation of the single-stage replica film, which was obtained by directly coating on the specimen surface. A plasma polymerization film was deposited by gaseous hydrocarbon monomer in a glow discharge.The present study further developed the freeze fracture method by means of a plasma polymerization film produces a three dimensional replica of chemically untreated cells and provides a clear evidence of fine structure of the yeast plasma membrane, especially the dynamic aspect of the structure of invagination (Figure 1).
Surface Ultrastructure of Human Ectocervix in Certain Pathological Conditions
Authors: Mukherjee S. , Guha T. , Chakrabarti B. , Chakrabarti P. 
Published: June 2020

The cervix is an important organ in reproduction. Its malfunction is frequently a factor for infertility. Ectocervix region does not appear to have received much attention although many studies have been reported on the endocervix. We report here our SEM observations on ectocervix in certain pathological conditions compared to normal ectocervix.Ectocervix specimens from human females with specific pathological disorders were processed for Scanning Electron Microscopy by conventional method and they were examined in a Philips SEM.The normal ectocervix is lined by flat layer of squamous epithelial cells with microridges (Fig. 1). These cells are known to be formed from columnar cells through metaplastic transformation. The cells of carcinoma-bearing ectocervix show a disorganised appearance (Fig. 2). In non-malignant tumour surface some cuboidal and few columnar cells were seen (Fig. 3). A cyst appears like an overgrowth on the surface of the squamous epithelium (Fig. 4). In ulcerated ectocervix a marked reduction of epithelial cells are observed (Fig. 5); the cells are devoid of microridges and, the large polygonal cells, as observed in normal tissues, have somehow acquired comparatively small hexagonal shape
Electron Microscopy in the Study of Natural Phytoplankton Assemblages
Authors: Sicko-Goad Linda 
Published: June 2020

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.
Cerebral Tubuloreticular Inclusions In Reye's Syndrome
Authors: Harb Joseph M. , Murphy Jerome V. , Tang Thomas T. 
Published: June 2020

IntroductionTubuloreticular inclusions (TRI) were first reported in patients with herpesvirus encephalitis or systemic lupus erythematosus (SLE). TRI are abnormal subcellular structures which consist of fine irregularly branched, anastomosing tubules within cisternae of endoplasmic reticulum. TRI have also been reported in blood lymphoreticular cells, vascular endothelial cells, mesenchymal cells, and epithelial cells in a variety of clinical conditions which include SLE and other autoimmune diseases, congenital immunodeficiency, lymphoproliferative disorders, neoplasms, neurodegenerative disorders, T-cell leukemia, and acquired immune deficiency syndrome (AIDS). We have recently reported an association of TRI with Reye's syndrome (RS). The inclusions were found in peripheral leukocytes of two unrelated patients with RS following a prodromal influenza respiratory infection. Subsequent to those studies we have retrospectively examined biopsy material from earlier cases of RS, and have identified TRI in the capillary endothelial cells from brain biopsies of three RS patients. The purpose of this report is to present these observations and to discuss the association of TRI with RS.
The Congenital Nephrotic Syndrome: A Review and Case Report
Authors: Price George , Cerezo Lizardo 
Published: June 2020

The congenital nephrotic syndrome (CNS) is a rare form of neo-natal nephropathy that generally occurs within the first three months of life, and is characterized by proteinuria, placentamegaly, and retarded intrauterine growth. Proteinuria in infants can result from a variety of other causes such as congenital infections (syphilis, CMV, etc.), mercury intoxication, and minimal change lesion, but CNS is the only nephrotic syndrome of neonates that is unresponsive to immunosuppressive drugs.This syndrome was first defined and extensively studied in Finland where this condition was estimated to occur in 1 per 10,000 births, and was found to be an expression of an autosomal recessive inheritence. It has also occured in children without a history of Finnish ancestry.The prognosis for these children is poor, most often resulting in death by the fourth year of life unless a renal transplant is received. A study of 17 transplants in children with CNS reported a 71% graft survival rate over a two year period with no recurrence of nephrotic syndrome in any transplants.
Preparation of the Buffy Coat From Small-Volume Blood Samples For Ultrastructural Study
Authors: Mitchell M. J. , Mirro E. J. , Black H. E. , Schwartz E. 
Published: June 2020

Electron microscopic examination of peripheral blood is a valuable technique in toxicological research. Blood can be collected for examination several times during a toxicological study. Compound-induced cellular changes detected in peripheral blood cells prior to the terminal necropsy may be an early indication of potential compound-related toxicity.The routine use of small rodents in toxicological studies presents a problem; the amount of blood available at interim collections is minimal. The following technique has been refined for the purpose of examining leukocytes in small blood samples (1 cc or less). Leukocytes are concentrated so that a maximal number per sample can be examined.
Structural modifications in H-implanted and laser desorbed Si
Authors: Zheng P. , Saint-Jacques R.G. , Boivin R. , Terreault B. 
Published: June 2020

Near-surface microstructural modifications of silicon which occur in hydrogen ion implantation and classical thermal desorption have already been reported. Our work is related to desorption using an intense and pulsed laser. The particularity of this technique is only the surface (≈2μm) heated. We report results of transmission electron microscopy (TEM) of the microstructural modifications in H-implanted and laser desorbed silicon.Silicon [001] oriented has been implanted with 5 keV H to a dose of 1017cm-2 and desorbed with a ruby laser (694.3 nm, 30 ns). It received an energy of 0.9 J.cm-2 and its surface temperature reached the melting point. This sample was totally desorbed as indicated by mass spectroscopy and checked by Elastic Recoil Detection. Plan-view [001] and cross-sectional [110] TEM samples were mechano-chemically thinned (10% HF + 90% HNO3). TEM dynamic imaging conditions (imaging vector g=220, w=0) were used to observe the defects.
SPECTRA: A program for processing electron images of crystals
Authors: Schmid M.F. , Dargahi R. , Tam M. W. 
Published: June 2020

Electron crystallography is an emerging field for structure determination as evidenced by a number of membrane proteins that have been solved to near-atomic resolution. Advances in specimen preparation and in data acquisition with a 400kV microscope by computer controlled spot scanning mean that our ability to record electron image data will outstrip our capacity to analyze it. The computed fourier transform of these images must be processed in order to provide a direct measurement of amplitudes and phases needed for 3-D reconstruction.In anticipation of this processing bottleneck, we have written a program that incorporates a menu-and mouse-driven procedure for auto-indexing and refining the reciprocal lattice parameters in the computed transform from an image of a crystal. It is linked to subsequent steps of image processing by a system of data bases and spawned child processes; data transfer between different program modules no longer requires manual data entry. The progress of the reciprocal lattice refinement is monitored visually and quantitatively. If desired, the processing is carried through the lattice distortion correction (unbending) steps automatically.
Twin boundary structure in L10 alloys
Authors: Singh Abha , King A.H. 
Published: June 2020

Ordered alloys have been of great interest in the last decades for their potential use as high temperature structural materials. The most commonly studied ordered alloys are Ni3 Al, with L12structure, and L1 0TiAl. Grain boundary fragility, however, is a major problem in the practical application of many ordered alloys, although it can be ameliorated in Ni3Al by boron doping. The problem calls for improved understanding of grain boundary structure in ordered alloys. Most studies so far have been done on alloys based on L12 and B2 structure. An investigation of twin boundary structure in L10 CuAu(I) has been carried out in the present work, by means of CTEM and computer image matching techniques.The twins in the present study are order twins; i.e. they are formed upon ordering, when a cubic to tetragonal phase transformation occurs. The lattice strains associated with the cubic-tetragonal transformation are accommodated by a repeated twinning structure which consists of alternating twins on parallel {101) planes, as observed by Pashley and Presland.
Attractive mode force microscopy of chiral liquid crystal surfaces
Authors: Terris B.D. , Twieg R. J. , Nguyen C. , Sigaud G. , Nguyen H. T. 
Published: June 2020

We have used a force microscope in the attractive, or noncontact, mode to image a variety of surfaces. In this mode, the microscope tip is oscillated near its resonant frequency and shifts in this frequency due to changes in the surface-tip force gradient are detected. We have used this technique in a variety of applications to polymers, including electrostatic charging, phase separation of ionomer surfaces, and crazing of glassy films.Most recently, we have applied the force microscope to imaging the free surfaces of chiral liquid crystal films. The compounds used (Table 1) have been chosen for their polymorphic variety of fluid mesophases, all of which exist within the temperature control range of our force microscope.
Characterization of oxide films formed on Inconel 600 and incoloy 800 during exposure to high-temperature water
Authors: Allem Rafik , L'Espérance Gilles , Gonzalez Francisco , Brennenstuhl Alex M. , Caron Mario 
Published: June 2020

The structure and composition of oxide films may give an insight into the corrosion resistance of nickel alloys of the type used as tubing in nuclear steam generators. This paper describes the results of a preliminary analytical TEM study aimed at characterizing the surface films formed on Inconel 600 and Incoloy 800 during exposure to high temperature water (300°C).Alloy coupons were exposed to water at pH 10. pH control was accomplished by additions of either sodium hydroxide or morpholine. Thin foils and extraction replicas were prepared to study the oxide films. Thin electron transparent sections through the oxide/metal interface region were produced using standard techniques. Quantification of the Energy Dispersive and Electron Energy Loss Spectroscopies (EDS and EELS) spectra was carried out using calibration kAB factors and calculated partial cross sections respectively. Identification of crystalline phases was achieved by Focused Beam Electron Diffraction (FBED).
Unique method of tissue culture preparation for EM
Authors: Wang Fen , Ledford Lindsay B. , Head Jonathan F. , Elliott Robert L. 
Published: June 2020

A simplified technique of growing monolayer cells for electron microscopic examination has been developed. Our procedure has eliminated many difficult steps and therefore is easier than those reported by others.Regular Beem capsules for routine embedding for electron microscopy were used(Fig. 1). Prior to tissue inoculation capsules were washed with 5% HCl and gas sterilized. A 0.5 ml cell suspension of MCF-7 cells (10,000/ml) was placed in the capsules and cells settled in the pyramid portion (Fig. 2). Culture medium was alpha-MEM with 10% FCS. Capsules were incubated at 37°C for 3 days. They were then fixed in 70% ethanol for 20 minutes and stained with crystal violet. The pyramid portion of the capsule was cut off and monolayer cell growth was confirmed by examination under a microscope (Fig. 3).