bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-speed electron counting system for TV scan-rate secondary-electron images of SEM
Authors: Yamada S. , Ito T. , Gouhara K. , Uchikawa Y. 
Published: June 2020

We reported a system for counting secondary electrons (SEs), with which SE image quality of SEM such as signal to noise ratio (SNR) and linearity were improved, in particular under the condition of low irradiation. The system had been developed for slow-scan rates (over 6 sec/flame). The TVscan rate (1/30 sec/frame) is often used to avoid charging of insulators and biological specimens. We developed a high speed electron counting system with which SE images can be obtained in the TVscan rate. This paper describes the new system attached to an SEM, and some experimental results obtained with it.A schematic diagram of the new system is shown in FIG.1, which consists of four main parts; Everhart-Thornley type detector (DT), main amplifier (MA), counter (CNT) and image processor (IP). In designing the system we took precautions for high speed data acquisition in the TV-scan rate. As described in the previous papers, the thermal noise and the fluctuations of the pulse height of the SE signal contained in the output of the DT can be removed through the CNT.
UHV-TEM studies of laser-induced damage
Authors: Savage T.S. , Ai R. , Dunn D. , Marks L.D. 
Published: June 2020

The use of lasers for surface annealing, heating and/or damage has become a routine practice in the study of materials. Lasers have been closely looked at as an annealing technique for silicon and other semiconductors. They allow for local heating from a beam which can be focused and tuned to different wavelengths for specific tasks. Pulsed dye lasers allow for short, quick bursts which can allow the sample to be rapidly heated and quenched. This short, rapid heating period may be important for cases where diffusion of impurities or dopants may not be desirable.At Northwestern University, a Candela SLL - 250 pulsed dye laser, with a maximum power of 1 Joule/pulse over 350 - 400 nanoseconds, has been set up in conjunction with a Hitachi UHV-H9000 transmission electron microscope. The laser beam is introduced into the surface science chamber through a series of mirrors, a focusing lens and a six inch quartz window.
X-ray photoelectron spectroscopy of annealed Co-Cr films
Authors: Demczyk B.G. , Estry H.W. 
Published: June 2020

Co-Cr thin films have been studied extensively as leading candidates for perpendicular recording media. The enhancement of the magnetic properties (saturation magnetization and coercivity) in rfsputtered Co-Cr films has been reported by several investigators. Concurrent work has revealed similar improvements in the magnetic properties of annealed Co-Cr films produced by magnetron sputtering. Honda et al. propose that compositional inhomogeneities in annealed films give rise to these properties changes. In this work, we have employed X-ray photoelectron spectroscopy (XPS) to investigate compositional changes in annealed Co-Cr layers of thickness 10-200 nm.Films were deposited from a Co-22wt%Cr alloy target onto glass (Coming Type 7059) substrates using a Varian DC Magnetron ("S" gun) sputtering system. Sputtering conditions included an argon pressure of lmTorr and room temperature substrates. The sputtering rate was 0.25 nm/sec. Annealing was performed at 360°C in a vacuum (10-6 Torr) in incremental times up to 49 hours.
A microstructural characterization of Co-Zr type permanent-magnet materials
Authors: Lawless K. R. , Hadjipanayis G. C. 
Published: June 2020

Considerable interest has been shown recently in the hard magnetic properties of Co-Zr, Co-Zr-B, and Co-Hf-B alloys, but as yet no detailed microstructural studies have been published. The Co-Zr phase diagram seems to be reasonably well known, although the crystal structure of the Co11Zr2 phase is only partially determined. This paper will report on some preliminary studies of rapidly solidified Co-Zr-B-Si and Co-Hf-B-Si alloys and binary Co-Zr alloys.All specimens used in this study were prepared by melt spinning. Specific alloys were heat treated at temperatures from 650 to 900°C. TEM specimens were prepared from ribbon material by ion milling.X-ray diffraction studies of these alloys all showed a characteristic broad peak centered around d = 0.205nm. Although it was obvious that this was a complex peak, attempts to deconvolute it were unsuccessful. SAD patterns revealed that major phases in the alloys were very heavily faulted, thus giving rise to the very confusing X-ray diffraction patterns.
Core excitation studies of poly(ethylene terephthalate) and molecular analogues by EELS
Authors: Rightor E. G. , Hitchcock A. P. , Urquhart S. G. , Wen A. T. 
Published: June 2020

The near-edge region of core ionization edges can be used as a probe of the local bonding and structure of atoms excited by incident radiation, such as in electron energy loss spectroscopy (EELS) or x-ray absorption techniques. Recent installation of efficient parallel EELS spectrometers in ATEMs promotes study of these transitions in radiation sensitive materials such as polymers. To study relationships between poly(ethylene terephthalate) [PET] structure and EELS transitions, we compared polymer spectra with molecular analogues.The PET examined (from Scientific Polymer Products) was cut using a diamond knife and a Reichert-Jung Ultracut E ultramicrotome with FC4E cryoattachment. A JEOL 2000FX TEM with a LaB6 filament and a Gatan parallel-EELS system was used to examine PET sections on holey carbon. The gas phase EELS of molecules (from Aldrich, Matheson) was performed under inelastic scattering conditions as described previously.
The Use of Microspectroscopy in the Stem for the Identification of Membrane Components
Authors: Hainfeld J. , Isaacson M. , Sogard M. 
Published: June 2020

In recent years, more notice has been given to the fact that the energy loss spectra of fast electrons transmitted through thin specimens may be employed to analyze their composition (e.g. refs. 1,2). A program to explore the usefulness of energy loss spectra (with a STEM) in identifying the components of biological membranes has been initiated.One would like to scan, for example, over an intact membrane surface and analyze, point by point, the composition. However, some preliminary studies are necessary: First, the energy loss spectra of each major membrane component must be determined; second, the change in these spectra with beam dose must be found, since damage may be a problem as resolution (and therefore dose) is increased; third, a practical scheme of obtaining point-bypoint data (i.e., pictures that relate composition to contrast) must be devised.
Ultrastructure of the Celis of a Fish Tastebud
Authors: Korte Gary E. 
Published: June 2020

Four types of specialized epithelial cells have been observed in the fish tastebud, within the capsule formed by the flattened epidermal cells. However, only two or three of these have been previously noted in any one species, including the glass catfish Kryptopterus bicirrhis, the subject of this investigation (1,2). For the first time, all four types of specialized cells have been observed,and an artifact of fixation relevant to the identification of these cell types has been uncovered.A single basal, or B cell lies on the basement membrane of the epidermis (Fig. 1). It makes many synapses with the afferent nerve plexus, which lies just above it. The other three cell types, designated S,L and T cells (Fig. 2A) are external to the nerve plexus, and only rarely make synapses onto nerves, confirming the observations of several other investigations.
Ultrastructural Description of three Different Epithelial Cell Types in Rat Mammary Gland.
Authors: Russo I.H. , Ireland M. , Isenberg W. , Russo J. 
Published: June 2020

The mammary gland is composed of epithelial and myoepithelial cells. In the present work, we show that the epithelial component is composed of three types of cells differing in their ultrastructural profiles.Sprague-Dawley virgin female rats, 60 to 100 days old, were sacrificed during estrus. The mammary gland was fixed in Karnovsky's fluid (1), embedded in Epon-Araldite (2), thin-sectioned, stained with uranyl acetate and lead citrate, and examined in an Hitachi HU-11A or a Siemens Elmiskop 1A. To see whether ultrastructural differences correspond to size differences, the nuclear and cytoplasmic areas of 1000 cells were determined from photographs at 10,000X, using a compensating polar planimeter.The population of epithelial cells in the mammary gland is comprised of three different cell types (Fig. 1): a) light cells, b) dark cells, and c) intermediate cells.
Preparation of Freeze-Stopped Rat Liver Tissue for Transmission Electron Microscopy
Authors: Lim B. S. , Veech R. , Slovis R. , Solomon J. D. 
Published: June 2020

The relationship of morphological integrity and viability of mitochondria in freeze-stopped cells is of considerable interest and importance to biological scientists. This study represents the preliminary work for obtaining ultrastructural data for comparison with glutamate dehydrogenase activity, a marker for mitochondria protein, on freeze-stopped liver tissue from the rat.The pellets of ground freeze-stopped rat liver were fixed in three different ways: (l) OsO4 fume fixation. The fixing chamber consists of a capped plastic centrifuge tube containing an open ampule of OsO4 crystals. The chamber was maintained at -90°C at all time before and during fixation. After an overnight fixing, the tissue pellets were gradually brought to 4°C in a refrigerator and postfixed in glutaraldehyde.
Rapid Infiltration of Biological Tissues Utilizing n-Hexenyl Succinic Anhydride (HXSA)/Vinyl Cyclohexene Dioxide (VCD), An Ultra-Low Viscosity Embedding Medium.
Authors: Mascorro Joe A. , Ladd Margaret W. , Yates Robert D. 
Published: June 2020

HXSA/VCD recently was introduced as an ultra-low viscosity embedding medium for biological electron microscopy (Mascorro et al., TSEM/LSEM Joint Symposium Proceedings, In Press, 1976). The medium utilizes a newly developed short carbon chain anhydride (HXSA) in combination with components of known low viscosities. The completed medium exhibits a markedly low viscosity (20 ±1 cps d 25°C) which facilitates rapid and complete infiltration in minimum time. The components and preparation of the medium are as follows:A small amount of standard mix includes 5 grams VCD, 10 grams HXSA, 0.75 gram Araldite RD-2 and 0.15 gram DMAE, combined gravimetrically. Components are drawn by syringe and dispensed into a dry beaker placed on a Mettler balance. The fluid nature of the medium allows precise measuring.
Considerations in Making Stereo Micrographs with the Scanning Electron Microscope - Positioning the Stereo Window
Authors: Walter Earl R. 
Published: June 2020

A variety of factors must be controlled in order to obtain stereo micrograph pairs with the SEM which provide maximum effectiveness along with ease of viewing. These include the following:1. Where possible, micrographs should be sharp from edge to edge. This may require the use of an Autofocus attachment although somewhat the same effect can be obtained by maintaining the point of sharpest focus near opposite edges of the two micrographs forming the stereo pair.2. The difference in tilt angle between the two micrographs of the pair should be kept in the4to 6° range to provide a normal perspective.3. Micrographs forming a stereo pair should be made at relatively low tilt angles to prevent large differences in the field of view of the two micrographs and to minimize the left to right magnification variations.
On the Shape of Field-Ion Emitters
Authors: Eaton H.C. , Ranganathan B.N. , Burwinkle T.W. , Bayuzick R. J. , Hren J.J. 
Published: June 2020

The shape of the emitter is of cardinal importance to field-ion microscopy. First, the field evaporation process itself is closely related to the initial tip shape. Secondly, the imaging stress, which is near the theoretical strength of the material and intrinsic to the imaging process, cannot be characterized without knowledge of the emitter shape. Finally, the problem of obtaining quantitative geometric information from the micrograph cannot be solved without knowing the shape. Previously published grain-boundary topographies were obtained employing an assumption of a spherical shape (1). The present investigation shows that the true shape deviates as much as 100 Å from sphericity and boundary reconstructions contain considerable error as a result.Our present procedures for obtaining tip shape may be summarized as follows. An empirical projection, D=f(θ), is obtained by digitizing the positions of poles on a field-ion micrograph.
Field Emission Analytical Electron Microscope
Authors: Harada Y. , Kokubo Y. , Goto T. , Tamura N. , Iwatsuki M. , Koike H. 
Published: June 2020

Recently, analytical electron microscopes (AEM), which provide the functions of the transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) have been put to practical use with a view to analyzing elements in micro areas, xo improve the performance of this type of AEM, a field emission gun was attached to our AEM instead of a conventional thermionic gun. This has allowed a sellected area smaller than several 100 Å to be easily analyzed. Moreover, an electron energy analyzer (EA) was attached to the AEM for detecting light elements which cannot be detected by the EDS.These modifications have resulted in an advanced type of an AEM, namely, a field emission analytical electron microscope (FEAEM).Fig. 1 shows a general view of our FEAEM. The feature of this FEAEM is that it is designed on the basis of a 100 kV field emission electron microscope provided with a strongly-excited objective lens having a very small aberration coefficient and with an eucentric goniometer tiltable to 60°.
Autocatalytic Nucleation of Omega Phase in a Beta-Titanium Alloy
Authors: Headley T. J. 
Published: June 2020

The well-known ββ+ω transformation has been observed in many b.c.c.- stabilized titanium, zirconium, and hafnium alloys(1,2). Although considerable controversy still exists regarding the exact mechanism(s) for formation of the ω phase, recent studies suggest that both the athermal and isothermal types form by the same mechanism and that they may therefore be considered equivalent products(3,4).The present observations are concerned with the formation of isothermal w in the B-titanium alloy RMI(38-6-44) [composition in wt.%: 3.4 Al, 8.3 V, 5.8 Cr, 3.9 Zr, 4.2 Mo, balance Ti] and form a part of a more general study of the aging characteristics of this alloy(5). The alloy was solution treated at 927°C, air-quenched, aged at appropriate temperatures, and examined in a Phillips EM 200 electron microscope. TEM failed to reveal the presence of athermal m in the solution treated and quenched material. Isothermal OJ formed during aging at 250° and 300°C, but it was not stable at temperatures of 350°C and above.
Nature and Distribution of Pyrite in Iowa Coal
Authors: Greer Raymond T. 
Published: June 2020

Iowa has a large reserve of high-sulfur coal. In view of the projected energy requirements for the state, in-state coal resources should provide a significant contribution. Environmental considerations and air pollution regulations emphasize the desirability of sulfur removal. Both microstructural and microchemical characteristics of Iowa coal relate to the choice and improvement of processing and purification procedures, as well as provide information which may aid in local correlation of deposits.Iron sulfides occur in the coal as nodules and narrow seams (up to 150 mm thick, thinning out over a distance of hundreds of millimeters) and in finely disseminated form. Individual pyrite euhedra occur predominantly in a size range of about one to 40 micrometers in diameter, with by far most of the crystallites being one to two micrometers in diameter (Fig. 1). This raises special characterization problems for routine conventional optical microscope studies. The pyrite also occurs as spherical assemblies of crystallites. These framboidal masses (after Framboise, the French for Raspberry) range from a few micrometers to several hundred micrometers in diameter, with most of them being approximately 10 and 20 micrometers in diameter (Fig. 2).
Lorentz Microscopy on Amorphous Films with Perpendicular Anisotropy as a Function of Temperature
Authors: Herd S. R. 
Published: June 2020

Lorentz microscopy on amorphous thin films of GdCoX (X=Au,Mo) with perpendicular anisotropy is used to show the change in the magnetic domain structure as a function of Q, the ratio of perpendicular anisotropy, Ku, to the square of the saturation magnetization . The films were prepared by RF-sputtering on to HaCl substrates from which they were floated off on to standard electron microscope grids. After a slight modification of the Philips EM-301 objective lens the current could be varied smoothly down to 0 which allowed use of the objective lens field as perpendicular bias field while the diffraction lens was used to obtain the out-of-focus image.As the perpendicular anisotropy increases, striped domains are formed in which the magnetization oscillates between ± TT/4 in and out of the plane of the film in the direction of the in-plane field component.
Structural Basis for Pulsations in the Eye of a Snail, Helix aspersa
Authors: Eakin Richard M. , Brandenburger Jean L. 
Published: June 2020

We have discovered a remarkable motion in the eye of the snail Helix aspersa, namely, regular contractions, about one per second, which are dependent upon light within the visible spectrum from approximately 440 nm to 640 nm. To observe the pulsations, an eye must be extirpated and its lens removed by an incision in the cornea. If a pulsating eye is placed in the dark, contractions cease, but they commence again within 10 to 30 seconds upon re-illumination. What is the mechanism for this motion?First, the pigmented supportive cells possess longitudinally arranged bundles of microfilaments which might be contractile, like filaments of actin. Single microfilaments measure about 40 Å in diameter.
Ultrastructural Investigation of the “Light Flash” Phenomenon Seen by our Astronauts
Authors: Philpott Delbert E. , Corbett R. , Black Sam , Turnbill Charles 
Published: June 2020

The light flashes seen by astronauts on their flights to the moon are believed to be caused by “heavy primaries” passing through the eyes. In order to learn more about this phenomenon and its effect on the retina, pocket mouse retinas were exposed to nitrogen beams (the heaviest nuclei available at Lawrence Radiation Laboratory) and also the evoked response from X-rays on rabbit eyes was observed.Pocket mouse retinas were exposed to nitrogen beams for the first time in the Berkeley Bevatron Accelerator. The pocket mice were positioned so as to expose one eye while the other eye was left unexposed. Both eyes were compared with controls (Fig. 1).
Physical Preservation Methods for Biological Material
Authors: Bullivant Stanley 
Published: June 2020

This review will be limited to physical preservation methods involving freezing, and will include discussion of freeze-drying, freeze-substitution, ultracryomicrotomy and freezeetching. Pre-treatment and freezing steps can be considered as common to all techniques.The most common pre-treatment is soaking in a cold 20% glycerol solution to provide protection against ice crystal formation. Glutaraldehyde fixation is often used before freezing. With special freezing techniques no pretreatment may be necessary.Freezing should be so rapid that it does not produce ice crystals larger than 2nm. in diameter. Following glycerol treatment, immersion in Freon 12 at its melting point of -155 C is adequate. Freezing in boiling liquid nitrogen is not usually satisfactory.
Polyethylene Glycol Diacrylates as Embedding Media for Electronmicroscopy
Authors: Peterson Richard G. 
Published: June 2020

Histochemistry on sections of electron microscopic tissue has been limited by the techniques available. Most embedment procedures cause changes in the chemistry and structure of the tissue. These effects are mainly due to the fixation with aldehydes, osmium or the dehydration necessary to embed the tissue in currently used plastics. A search for something which might be more effective has led us to the polyethylene glycol diacrylates (Polysciences, Inc.). These monomers are soluble, or partly soluble in water, are not lipid solvents, and are readily polymerized into sectionable plastics at room temperature or lower with U. V. light.Tissue from rats was fixed by either perfusion or immersion in aldehydes of various compositions. Tissue was infiltrated with polyethylene glycol 400 diacrylate containing 1% benzoin.
Nucleic Acid Molecules Prepared by Monolayer Techniques
Authors: Lang Dimitrij 
Published: June 2020

The success of the protein monolayer technique for electron microscopy of individual DNA molecules is based on the prevention of aggregation and orientation of the molecules during drying on specimen grids. DNA adsorbs first to a surface-denatured, insoluble cytochrome c monolayer which is then transferred to grids, without major distortion, by touching. Fig. 1 shows three basic procedures which, modified or not, permit the study of various important properties of nucleic acids, either in concert with other methods or exclusively:1) Molecular weights relative to DNA standards as well as number distributions of molecular weights can be obtained from contour length measurements with a sample standard deviation between 1 and 4%.
Structural Variations of Polyphosphate Bodies in Blue-Green Algae
Authors: Sicko Linda M. 
Published: June 2020

Polyphosphate appears to be a ubiquitous component of all microorganisms. Electron microscopic examination of blue-green algae reveals bodies which are usually spherical, and have a wide range of electron densities. From work conducted in our laboratory, it appears that the image of the polyphosphate bodies varies with the culture conditions as well as the stage of development under constant culture conditions. The following report describes the various images one can observe.For most experiments, the blue-green algae were fixed by the method of Pankratz and Bowen. The algae were pelleted, the culture media poured off, and the pellet was resuspended in 1% OsO4 buffered at pH 6.2 for 3 hours at room temperature.
Quantitative Ultrastructural Study of Mitochondrial Form After Partial Hepatectomy
Authors: Jann Brown W. , Verity M. Anthony 
Published: June 2020

Induced swelling of isolated residual rat and mouse liver mitochondria following partial removal has been shown to be diminished. This observation can be explained by two possible mechanisms; (a) the conformation of organelles in residual liver is altered and already swollen prior to isolation or, (b) the isolated mitochondria are rendered unreactive to certain swelling inducing systems because of specific changes that have occurred in the membrane.In order to evaluate the former of these proposed mechanisms, quantitative morphometric analysis of the heterogeneity of mitochondria has been attempted in situ by ultrastructural techniques after the manner of Bahr.