bluuebunny/crossref_metadata_2025 huggingface dataset:
The Optical System for the One Million Volt U.S. Steel Microscope Column
Authors: Reisner J. H. , Coleman J. W.
Published: June 2020

The design of an optical system for million volt operation extends existing practice nearly to its limits, and certainly into the area of iron saturation, and coil power limitations. Serious design problems arise from the wide range of accelerating voltage (100 to 1000 kV) provided, which are for design purposes equivalent to corrected voltages (V*) of 110 to 2000 kV. To prevent alignment problems transverse fields have been reduced by the use of sufficient iron in magnetic circuits and by extreme care with the symmetry of all iron parts.

Minimum objective focal lengths for a 1 cm bore lens (S/D=l), range from 6 mm. at 1000 kV with a k2 value of 1 to 2 mm. at 100 kV at k2 = 17. Performance characteristics are displayed in Figures 1, 2 and 3. While operation can be carried out over the whole voltage range with a 6 mm. focal length, an externally adjustable Z axis (axial) specimen position has been included in the stage, to permit operation with shorter focal lengths at lower voltages.
Injector for a 100-500 kV Linac Electron Microscopy Source
Authors: Coleman John W.
Published: June 2020

The injector to be described is a component in the Electron Injector-Linear Accelerator—Condenser Module for illumination used on the variable 100-500kV electron microscope being built at the Radio Corporation of America for the University of Virginia.

The injector is an independently powered, autonomous unit, operating at a constant 6kV positive with respect to accelerator potential, thereby making beam current independent of accelerator potential. The injector provides for on-axis ion trapping to prolong filament lifetime, and incorporates a derived Einzel lens for optical integration into the overall illumination system for microscopy. Electrostatic beam deflectors for alignment are an integral part of the apparatus. The entire injector unit is cantilevered off a door for side loading, and is topped with a 4-filament turret released electrically but driven by a self-contained Negator spring motor.
Replication of the Fracture Surfaces of Impact Plastics
Authors: Prestridge Eddie B.
Published: June 2020

Most of the electron microscope studies of the fracture surfaces of impact plastics have been made using direct carbon replication. This method of replication is very difficult to employ on the rough, non-glassy fractures obtained from rubber reinforced plastics such as acrylonitrile-butadiene styrene (ABS) types. The surfaces are too rough to allow the easy removal of the thin carbon film and many replicas are lost before a usable one is obtained. Most recently a Japanese worker reported a two-stage polyvinylalcohol (PVA) carbon replica which worked well on etched surfaces of plastics. Here, too, when the PVA film is thick enough to strip from rough surfaces, the film swells so badly when removed by water washing that the carbon replica is destroyed. The method described here is a two-stage PVA-carbon replication system that from even very rough surfaces obtains large unbroken final replicas.
Electron Microscopy of Aluminum Surfaces Prepared for Welding
Authors: Johari O. , Dragen R. , Saperstein Z. P. , Kizer D. E.
Published: June 2020

Before aluminum alloys are welded, they are usually subjected to some kind of surface treatment. This may involve machining, solvent degreasing, chemical cleaning, anodizing, etc. Storage time until welding often means exposure to a variety of environmental conditions.

It has long been known that weld quality depends on the condition of the surface. A systematic program was started in our laboratory (ref. 1) to investigate and characterize surfaces and the associated weld-defect potential as a function of different treatments. The characterization of surfaces includes topography, metallography, quantitative and qualitative determination of adsorption of contaminants, and the nature of the oxide layer by electron microscopy. The electron replication studies are reported herein.
On the Precipitation of Y′ and M23C6 in an Aged Nickel-Base Alloy
Authors: Kear B. H. , Rowe G. M. , Copley S. M.
Published: June 2020

As-cast Mar-M200 consists of ∼60 vol. % coherent precipitate of γ′ (Ni 3Al solid solution) in a matrix of γ (nickel solid solution). In the solutionized and quenched condition, Fig. 1 (a), the γ′ particles are ∼50-100Å Dia., and exhibit long range order; see relatively weak superlattice reflections (S) compared with main reflections (M) in the inset of Fig. 1 (a). Note that the equilibrium partitioning of the solid solution elements between the γ and γ′ phases may not have been realized owing to the fast quench. Quenched-in thermal vacancies should facilitate exchanges in nearest neighbor atoms to produce ordered regions of γ′. Aging at 800°F gives γ′ particles ∼750¥, Fig. 1 (b), which are recognizably cuboidal in shape. Aging at 1550°F yields γ′ particles ∼1500¥, Fig. 1 (c), together with new precipitates of M23Cg6 carbides (arrows) and many stacking faults.
Phenomena Associated with Oxygen in Titanium
Authors: Lee E. U. , Garner P. A. , Owens J. S.
Published: June 2020

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.

Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.
Electrolytic Isolation of Twin-Type Shock Deformation Structures
Authors: Grace F. I. , Murr L. E.
Published: June 2020

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.
Channeling in Quench-Hardened Gold
Authors: Bapna M. S. , Mori T. , Meshii M.
Published: June 2020

When pure gold is quenched from high temperature and aged at ambient temperature, tetrahedral stacking faults (TSF) are formed by clustering of quenched-in vacancies. At the same time, the specimen is hardened. This quench-hardening of gold was studied with special attention to deformation morphology and the change of internal structure. Polycrystalline gold sheets 0.1 mm. thick were quenched from 1020°C into brine at −25°C with a quenching rate of 5 × 104°c/sec and subsequently aged for 1 hour at 0°C. This was followed by the final aging treatment at 100°C for 1 hour to produce the uniform distribution of TSF of small size. The size and the density of TSF were ∼ 200 Å and ∼ 2.5 × 1015/cm3 respectively. After electropolishing, the specimens were extended in an Instron machine at 245°C at a strain rate of 2 × 10−4/sec.
Extended Preservation of Iron for Transmission
Authors: Abrahamson II E. P. , Dumais M. W.
Published: June 2020

In a transmission microscopy study of iron and dilute iron base alloys, it was determined that it is possible to preserve specimens for extended periods of time. Our specimens were prepunched from 5 to 8 mil sheet to microscope size and annealed for several hours at 700°C. They were then thinned in a glacial acetic-12 percent perchloric acid solution using 10 volts and 20 milliamperes, at a temperature of 8 to 14°C.

It was noted that by the use of a cold stage, the same specimen can be observed for periods up to one week without excess contamination. When removal of the specimen from the column becomes necessary, it was observed that a specimen may be kept for later observation in 1,2 dichloroethene or methanol for periods in excess of two weeks.
Scanning Electron Microscopy of Neural Networks
Authors: Lewis E. R. , Zeevi Y. Y.
Published: June 2020

Our understanding of nervous-system operation has been frustrated at almost every level. We do not know the physical mechanisms underlying sensory transduction or single-neuron operation. We are unable to observe or infer the details of signal flow and interaction in single neurons or in networks of neurons; and our present techniques for mapping neural networks are so cumbersome that topography has been related explicitly to function in only the rather simple case of the lateral eye of Limulus. Clearly, new tools are desparately needed. With its ability to sense surfaces and its high resolution over large depths of field, the scanning electron microscope offers the prospect of being such a tool. This prospect can be realized, however, only if the relevant surfaces can be exposed to the beam of the microscope. In nervous tissue, the relevant surfaces are the boundaries of the neurons and their processes.
Powder Morphology of Nuclear Ceramics by Scanning Electron Microscopy
Authors: Daniel J.L. , Mayhan S.J. , Weber E.T. , Barr M.J.
Published: June 2020

The value of scanning electron microscopy in the study of materials’ behavior has been well established. An application of particular importance in ceramics research is the study of powder morphology and the relationships between starting powders, fabrication steps and the finished compact.

Since the source powders usually comprise submicron particles accumulated into larger agglomerates, detailed information of the size, shape and general appearance has been difficult to obtain by conventional electron microscopy. While replicas reveal some detail of the outer surface, and direct transmission techniques produce silhouettes of the powder particle masses, the complete structure is not shown satisfactorily by either method.
The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia
Authors: Lim D.J. , Lane W.C.
Published: June 2020

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.

The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).
‘Ghost’ Stacking Fault Images in a Nickel-Ease Alloy
Authors: Oblak J. M. , Kear B. H.
Published: June 2020

Previous work has shown a relationship between the formation of extrinsic growth faults and the precipitation of Cr rich M23C6 carbide in several nickel-base alloys. These stacking faults grow through both fcc γ matrix and LI2 γ' precipitate by the climb of Frank partials. At a later stage of aging, after formation of large discrete particles of M23C6, the stacking faults begin to anneal out. However as lllustrated in Figure la,b residual 'ghost' stacking fault images often remain behind. The ghosts labeled I and II lie on the (lll) plane; the associated triangular stacking fault segments are extrinsic in nature and bounded by ⅓ Frank partials. The third ghost (III) lies on and is joined to the intrinsic fault at the left by a ⅓ Frank partial. While a large number of diffraction conditions were examined, no dislocation was visible at the position x-x where ghost I ends in the matrix. This is not always the case since total lattice dislocations have also been observed at similar ghost/matrix boundaries.
The Elmiskop 51, A Transmission Electron-Microscope with Permanent Magnet Magnification System
Authors: Müller K. , Ruska E. , Neff H.
Published: June 2020

For routine analyses in laboratories of variing specialities, where a large number of electron micrographs are to be obtained quickly, the Elmiskope 51 has been developed.

It has an accelerating voltage of 50 kV and permits Electron microscopic magnifications in steps of 1250:1 to 12 500:1. With high-resolution photoemulsions a point to point resolution of 20 to 25 Å can be reached.
Comparative Investigations on Various TV Image Transmission Systems used with Electron Microscopes
Authors: Herrmann K. -H. , Krahl D. , Kuebler A.
Published: June 2020

Television systems for transmitting the final image of an electron microscope offer some advantages as compared with the usual method of observing the final image on the fluorescent screen:

1.

The current density in the object are a can be greatly reduced, without considerable loss in resolution.

2.

(Electronically, in a limited range, the contrast can be increased.)

3.

Easy focussing and astigmatism correction at very low beam current is possible, specially in case of high electron optical magnification without necessary dark adaption.

4.

Several views can observe the transmitted final image at the same time.
A Prototype High Vacuum Electron Microscope
Authors: Hartman Richard E. , Akahori Hiroshi , Garrett Charles , Hartman Roberta S. , Ramos Peter L.
Published: June 2020

The Hitachi HV-1 electron microscope was designed to be a prototype for a truly high vacuum instrument. The basic concepts for the design were developed from experience obtained in the conversion of a Siemens Elmiskop I at Walter Reed Army Institute of Research and of a JEM 6-C at New York Medical College. The pumping system was designed and constructed by Perkin-Elmer-Ultek in Palo Alto and the column and electronics were designed and constructed by Hitachi at the Naka Works in Mito, Japan. The pumping system and the column were first joined for preliminary tests at the Naka Works. The system was then shipped to New York where it has been installed at New York Medical College. Final performance tests are still in progress.
Observations on Evaporated Tantalum Films
Authors: Berting F. M. , Lawless K. R.
Published: June 2020

High purity tantalum was vacuum deposited by electron beam evaporation onto polished {100} surfaces of single crystal MgO heated to temperatures between 700°C and 800°C. An ion pumped vacuum system was used, giving a vacuum of from 3·10-6 to 5·10-7 torr during actual deposition.

The diffraction pattern from these Ta films (Figure 1) is very similar to that observed by Hutchinson and Olsen for one-quarter hour annealed Nb films.
A Method using T.E.M. and S.A.D. to Define the Structure of Anodized and Air Grown Oxide Films on Pure Titanium
Authors: Shaw G. G.
Published: June 2020

We have determined the mechanical properties of aluminium oxide films by growing anodic films of known structure and thickness and relating these to natural oxide films. We are now investigating the mechanical properties of titanium oxide films, and to relate the stricture of anodic titania films to natural oxide films, we must, have more information than is contained in the literature.
Image Degeneration by Charging Effects on Photographic Media
Authors: Reisner J. H. , Horner J. A.
Published: June 2020

Insulators irradiated by a high energy electron beam in vacuum become charged positively. The charging produces an electrostatic field which causes the incident beam to be deflected progressively toward the effective charge center. Photographic materials are essentially dielectrics and exhibit charge phenomena which can disturb an image. The charging conditions are aggravated by suspending the photo material remotely from ground, or a conducting surface.
Transmission Electron Diffraction Contrast Microscopy of Tungsten Wire
Authors: Tufts Charles F.
Published: June 2020

In order to make a critical study of the crystallography in tungsten wires by transmission electron diffraction contrast microscopy, thin sections should be prepared without pressing the wire into ribbon or without using mechanical polishing procedures which can modify the crystallographic character. This paper describes a method that employs electrolytic and chemical polishing to form thin sections in tungsten wires of 0.010 inch diameter.
Analysis of Calcium Fluoride Phosphate Particles Using Transmission Electron Diffraction Contrast Microscopy and Electron Diffraction
Authors: Tufts Charles F. , Emma Thomas A.
Published: June 2020

Although transmission electron diffraction contrast microscopy (TEDCM) and selected area electron diffraction (SAED) have been used extensively to study crystal perfection and defects in thin sections prepared from large crystals, no concentrated effort has been made to develop such a methodology for individual particles contained in a powder specimen. This is unfortunate since the behavior of the powder in practice can be affected significantly by variations in crystal perfection from particle to particle.
Existence of Cubic ZrO2 at 300°C on Bulk Zirconium
Authors: Ploc R.A.
Published: June 2020

The manner in which ZrO2 forms on zirconium at 300°C in air has been discussed in the first reference. In short, monoclinic zirconia nucleates and grows with a preferred orientation relative to the metal substrate. The mode of growth is not well understood since an epitaxial relationship which gives minimum misfit between the zirconium ions in the metal/oxide combination is not realized. The reason may be associated with a thin cubic or tetragonal layer of ZrO2 between the inner oxygen saturated metal and the outer monoclinic zirconia.
The Annealing of Radiation Produced Voids in Aluminum
Authors: Brimhall J. L. , Mastel B.
Published: June 2020

Voids have been reported in high purity nickel, copper, and aluminum after neutron irradiation at temperatures of ∿ 0.30 Tm. These voids have been attributed to the condensation of the supersaturated vacancies which are formed during irradiation. The purpose of this report is to describe the voids formed in aluminum and their annealing behavior.
Electronic Deposition and Lyophilization of Sprayed Suspensions of Protein for Electron Microscopy
Authors: Stasny J. T. , Vernon S. K. , Rubin B. A.
Published: June 2020

The use of electronic deposition as a technique for the collection of microdroplets from nebulized suspensions of protein has been previously described. This technique has been extended for use with the subsequent freezing and drying of nebulized aerosols for studies concerned with the dimensional preservation of protein structure.

Considerable difficulty is encountered when attempts are made to collect a nebulized aerosol onto a pre-cooled surface. The usual method of deposition involves the high-velocity, forced-air impaction of microdrop1ets onto a substrate surface. Therefore, the aerosol is both formed and delivered to the substrate surface by the same force. Static charging created by the formation of the aerosol, plus the wind turbulence created by the use of highpressure delivery system, prevents the majority of the microdrop1ets from reaching and adhering to the substrate surface.
Electron Microscopy of Unstained Biomacromolecules
Authors: Kleinschmidt A.K. , Vasquez C.
Published: June 2020

The high contrast studies of nucleic acid filaments and proteins applying acetonic solutions of uranyl acetate (10-4) have developed new procedures to observe the macromolecules under similar conditions omitting the stain at low (≤ 104 times) or high (≥105 times) magnifications. The most improving step is choosing extremely thin carbon support films, which are backed by a heavy collodion layer. The collodion is removed from the carbon film by "melting" in an oven (c. 180°C, 10 min.), after the mounting of macromolecules is completed. The thickness on the carbon film was estimated by ellipsometry to range below 70 Å.
High Resolution Electron Microscopy of DNA
Authors: White J.R. , Roller T. , Beer M. , Bartl P.
Published: June 2020

Observations of molecular detail in the electron microscope is limited by the presence of the familiar dotty contrast produced by the evaporated carbon support films commonly employed, resulting in the loss of information well within the resolution capability of modern instruments. While theoretical studies indicate that image contrast from one to three layers of graphite would be almost negligible, such films of 10Å thickness or less would not be expected to be sufficiently robust for use with current techniques for molecule deposition. Nevertheless, crystalline support films of greater thickness (say 100-200Å), should still be superior to disorganized material of similar chemical composition image.
Ultrastructural Studies on the Chondrocyte-Matrix Relationship in the Epiphyseal Plate
Authors: Hagerty Jon C. , Tousimis A.J.
Published: June 2020

Although numerous publications have appeared in the literature describing chondrocyte-matrix relationships, the mechanism of mineralization in the epiphyseal cartilage remains obscure. This paper reports our results on the ultrastructural aspects of the chondrocyte-matrix system in the proliferation, maturation and mineralization zones of the epiphyseal cartilage of the rat tibia.
Yolk Sphere Formation in the Oocyte of Drosophila Melanogaster
Authors: Cutamlngs Michael R.
Published: June 2020

Ultrastructural studies on diverse insect species have demonstrated that micropinocytosis occurs during the vitellogenic stages of oogenesis. It should be kept in mind that the demonstration of micropinocytosis does not preclude intraovarian yolk synthesis, and in fact, ultrastructural evidence indicates that in Drosophila, intra-ovarian yolk synthesis may play an important role in the formation of mature protein yolk spheres.
The Structure and Ultrastructure of Granulated Cells in the Metrial Gland of Pregnant Rats
Authors: Cardell Robert R.
Published: June 2020

Granulated cells, termed "endometrial granulocytes", populate the uteri of a variety of mammals under certain physiological conditions, and evidence has been presented that such cells are involved in the synthesis and secretion of relaxin (2 and 3). In the pregnant rat the granulocytes are located in specific reqions of the uterine tubes called "metrfal glands", and within the gland the presumed secretary cells are found primarily in several layers around blood vessels. Each cell is approximately spherical and has a cluster of granules which are phloxinophilic after staining by Lendrum's phloxine-tartrazine method. The cluster of granules lies near the eccentrically located nucleus, and in binucleate cells occurs between the two nuclei. The granules are approximately 1.5µ in diameter.
Effects of Steroids on Fetal Rat Liver
Authors: Zaki F. G.
Published: June 2020

Fetal and neonatal liver injury induced by agents circulating in maternal plasma, even though well recognized, its morphological manifestations are not yet established. As part of our studies of fetal and neonatal liver injury induced by maternal nutritional disorders, metabolic impairment and toxic agents, the effects of two anti-inflammatory steroids have been recently inves tigated.

Triamcinolone and methyl prednisolone were injected each in a group of rats during pregnancy at a-dosage level of 2 mgm three times a week. Fetal liver was studied at 18 days of gestation. Litter size and weight markedly decreased than those of control rats. Stillbirths and resorption were of higher incidence in the triamcinolone group than in those given the prednisolone.
Ultrastructure of Choriocarcinoma in Vitro
Authors: Garancis John C. , Pattillo R. A.
Published: June 2020

Growth of cell system (BeWo-cell line) derived from human gestational choriocarcinoma has been established and continuously maintained in-vitro. Furthermore, it is evident from the previous studies that this cell line has retained the physiological function of the placental trophoblasts, namely the synthesis of human chorionic gonadotrophil(HCG).

The BeWo cells were relatively small and possessed single nuclei, thus indicating that this cell line consists exclusively of cytotrophoblasts. In some instances cells appeared widely separated and their lateral surfaces were provided with numerous microvilli (Fig.1).
Oxygen Effects on Tissue Culture Cells
Authors: Philpott Delbert E. , Takahashi Akira , Turnbill Charles
Published: June 2020

Tissue culture cells of two varieties, L-929 mouse fibroblasts and Don Chinese Hamster lung, were exposed to 100% oxygen at one atmosphere and one-third of one atmosphere. When exposed to oxygen, the pH of the medium rose rapidly from 7.4 to about 8.4 and remained at this level. The organelles and general appearance of the cytoplasm were altered.

In the control cells two or three small Golgi apparatus (G.A.) are usually observed. However, after oxygen exposure the G.A. appears dilated, in closer proximity to the nucleus, larger and apparently decreased in number. The endoplasmic reticulum decreases in amount and size. Concurrently, the number of ribosomes also decreases giving the cytoplasm a lighter appearance.
Quantitative Stereology of Rat Liver Following CCI4 Poisoning
Authors: Loud Alden V. , Landisman Laurie
Published: June 2020

The technique of quantitative stereology has been used to study the effect of carbon tetrachloride poisoning on rat liver cells. A single feeding of CCl4, 0. 5 ml per 100 gm body weight, induces rapid changes in the mitochondria, lysosomes and endoplasmic reticulum of hepatic parenchymal cells. These changes show a characteristic lobular distribution. The quantitative method enables the measurement of the surface areas of rough- and smooth - surfaced endoplasmic reticulum and the average number, size and surface: volume ratios of cytoplasmic organelles. In the present experiment, live'r cells were sampled from the peripheral, mid-zonal and centrilobular regions of hepatic lobules at 30, 60 and 120 minutes after a single forced feeding of CCl4 by stomach tube.
The Development of Electron Optics
Authors: Mulvey T.
Published: June 2020

Research into the properties of cathode rays started in the 1850's when Geissler found out how to make vacuum tight gas-metal seals. It was soon discovered how to deflect the beam and concentrate it into a relatively small spot by means of a long magnetic solenoid, the theory of which was well established. Gabor's short concentrating coil complete with iron outer-shroud, shown in Fig 1., was introduced into a high voltage oscillograph in the period 1924-1926. It worked well but did not fit into the classical theoretical framework. The correct explanation of the action of a short coil in focussing an electron beam and its analogy with the focussing effect of the “burning glass” was first given by Hans Busoh in 1926. Busch left several questions open concerning the optical analogy and in 1928 Max Knoll and his student Ernst Ruska began in Berlin the first systematic investigation in “electron-optics”, with the aid of the electron-optical bench shown in Fig 2.
A Field Emission Electron Microscope
Authors: Tonomura A. , Komoda T.
Published: June 2020

We have developed a field emission electron microscope. Although field emission gun requires ultra high vacuum and skillful technique, it brings about the favorable characteristics of high brightness and small energy spread. This characteristics will enable a significant progress in coherent electron optics and high resolution electron microscopy, especially in electron beam holography.

Its column is Hitachi HU-11C Electron Microscope modified for ultra high vacuum operation, and it is evacuated with five ion pumps. Field emission gun is divided into two parts and is evacuated differentially with two ion pumps and a sublimation pump. The final pressures in these rooms are 5x10-10 Torr and 5x10-8 Torr respectively.
Quadrupole-Octopole and Foil Lens Corrector Systems
Authors: Thomson M. G. R. , Jacobsen E. H.
Published: June 2020

The theorem due to Scherzer which states, in essence, that a conventional axially symmetric, magnetic or electrostatic lens can never be free from third order spherical aberration is well known. Attempts to circumvent this limitation have been carried out over the past thirty years with little result, but meanwhile the ill effects have been minimized by using magnetic lenses of very short focal length.

The most studied alternative is the use of doubly symmetric strong focusing lenses. The first order imaging is performed with three or more quadrupoles, and the third order aberrations corrected with three octopoles. The design by Deltrap for example has no first order effect other than to invert the image, and has a third order spherical aberration coefficient which exactly cancels out that of the magnetic objective lens with which it us used. To avoid chromatic aberration this magnetic objective lens must have a very short focal length (2 mm for 100 kv operation with a resolution of 1 Å), and the overall system then has so much coma that the field of view is limited to 50 Å diameter.
Quantitative Analysis in High Resolution Transmission Scanning Microscopy
Authors: Crewe A. V. , Wall J.
Published: June 2020

The scanning microscope is ideally suited for gathering quantitative information about an object, since its outputs are voltage signals which are measures of the interactions of the incident beam with the volume of the specimen struck by the beam. These signals vary in real time as the beam scans and can be processed electronically to assign a “number” to each element of the scanned matrix.

Elastic and inelastic scattering cross sections have been selected as the two useful numbers to characterize a specimen since both are 1) additive functions of specimen composition, 2) unambiguously measurable with high efficiency, 3) Independent of microscope parameters, and 4) measurable with high spatial resolution (<5Å).
High Resolution Electron Microscopy Using Phase Plates
Authors: Thon F. , Willasch D.
Published: June 2020

The phase contrast transfer properties of objective lenses used in electron microscopy are not at all satisfactory and therefore the interpretation of phase contrast images is quite limited in the high resolution field. Phase contrast, however, is the dominant factor in creating contrast in high resolution electron microscopy. This is why methods which promise to improve the transfer conditions are of great importance.

A series of experiments has been reported to improve the contrast transfer conditions by zonal or semicircular filtering in the back focal plane of the objective lens or in subsequent light optical reconstruction. By these methods the transfer properties can be improved only to a certain degree.

For ideal imaging a transfer function would be desirable that is of constant value for the whole spatial frequency spectrum relevant to high resolution microscopy. This should in principle be attainable by inserting a phase shifting foil of varying thickness into the back focal plane.
Use of an Energy Dispersive X-ray Spectrometer on a Transmission Electron Microscope
Authors: Geiss Roy H. , Jesser William A.
Published: June 2020

An Ortec Si(Li) energy dispersive X-ray detector designed for use on a Cambridge scanning electron microscope has been coupled to a Siemens transmission electron microscope by replacing the side tilt control on the Siemens by a brass tube as shown in figure 1. The Siemens specimen holder was modified to tilt the specimen approximately 20° from a horizontal position and to elevate it such that it is just visible to the detector through the side port. This increased specimen height requires an objective focal length of greater than 8 mm and consequently effects a lower resolution of the image, especially at low accelerating voltages. The peak/background in the X-ray spectra is best at 40kV, however, and deteriorates progressively with increasing accelerating voltage.

Experiments similar to those of Fuchs, who employed a wavelength dispersive system on a Siemens TEM to measure film thickness, were repeated with the present energy dispersive system by analysing spectra from vacuum deposited gold films of various thicknesses. A linear relation between peak height and thickness was confirmed for several films up to 2000Å thick by comparing spectra from two adjacent grid squares, one covered by a single thickness of gold, the other covered by a double thickness, and noting that the peak heights were in the ratio of 1:2 to within a few percent.
New Three-Dimensional Algebraic Reconstruction Techniques (Art)
Authors: Gordon Richard , Bender Robert
Published: June 2020

Algebraic reconstruction techniques (ART) for 3-dimensional reconstruction from electron microscope data have been developed and implemented in this laboratory. These methods are an alternitive to the Fourier method of de Rosier and Klug and have several advantages over it, such as:

relatively few views are required (about 6-12)

limited angular ranges give useful reconstructions (+/-30°)

no presumption of symmetry is necessary for facile implementing

computation is faster

the computation is stable in the presence of noise

The dimensionality of the problem may be reduced from three to two by tilts about a single axis, so that planes perpendicular to the axis of tilt are independent of each other. This is not absolutely necessary, but is by far the most tractable mode computationally. A typical input data set, then, consists of m≥6 photos of the same region of the specimen at several known angles of tilt about the same axis. In general the direction of the tilt axis is not known.
Resolution Enhancement in Electron Microscopy by A Posteriori Holographic Image Deblurring
Authors: Stroke G. W. , Halioua M. , Saffir A. J. , Evins D. J.
Published: June 2020

A new refinement of the holographic image deblurring method originated by Stroke in 1967 has now permitted us to demonstrate an increase of resolution to less than 70Å in a scanning electron(SEM) microcraph taken with a commercial microscope(MAC SX-II) under the best normal operating conditions which had been considered to be “realistic” for “average specimens” and the type of instrument used, according to generally accepted criteria, e.g. according to C.W.Oatley, W.C.Nixon and R.F.Pease, A.N.Broers and others. We have obtained the same increase of resolution, by factors certainly in excess of 2 and more, as a part of yet unpublished collaborative work of us with Prof. Albert V. Crewe, in which we have succeeded in enhancing micrographs obtained at much higher magnifications (in excess of 800,000) in the much higher resolution transmission scanning mode, indicating an enhancement of resolution from about 5 Å to probably much better than 2.5Å. The principle of holographic resolution and contrast enhancement is theoretically equally applicable to high-resolution transmission electron microscopy of the “convential” type, and the theory has been unquestionably confirmed by the results obtained at the time of this writing.
High Voltage Transmission Microscopy of Surveyor III Camera Shrouds
Authors: Duff W. R. , Thomas L. E. , Fisher R. M. , Radcliffe S. V.
Published: June 2020

Successful retrieval of the television camera and other components from the Surveyor III spacecraft by the Apollo 12 astronauts has provided a unique opportunity to study the effects of a known and relatively extensive exposure to the lunar environment. Microstructural effects including those produced by micro-meteorite impact, radiation damage (by both the solar wind and cosmic rays) and solar heating might be expected in the materials used to fabricate the spacecraft. Samples received were in the form of 1 cm2 of painted unpainted aluminum alloy sheet from the top of the camera visor (JPL Code 933) and the sides (935,936) and bottom (934) of the lower camera shroud. They were prepared for transmission electron microscopy by first hand-grinding with abrasive paper to a thickness of 0.006". The edges were lacquered and the sample electropolished in 10% perchloric methanol using the “window” method, to a thickness of ~0.001". Final thinning was accomplished by polishing 3 mm punched disks in an acetic-phosphoric-nitric acid solution.
Preparation of Transmission Electron Microscopy Samples from Silicon Integrated Circuits
Authors: Smith P. J. , Kulkarni M. V. , Troutman H. A.
Published: June 2020

A new preparation technique for transmission electron microscopy samples has been developed which allows an individual device within a silicon integrated circuit to be thinned.

Typical devices within present silicon integrated circuits are located in the top few microns of a silicon chip, Fig. 1, and have lateral dimensions on the order of a fraction of a millimeter. Sample preparation for electron microscopy is usually accomplished by jet-etching the bottom side of the wafer, directly under the device of interest; thickness is estimated by the color of transmitted light. It is extremely difficult to ensure that the sample will be thinned in exactly the area of interest since the jet is incident on the bottom side of the sample while the device is on the top side, making exact alignment difficult; the jet is large compared to transistor dimensions; the presence of differently doped regions leads to non-uniform thinning.
The Interpretation of Crystal Lattice Images
Authors: Cowley J. M. , Iijima Sumio
Published: June 2020

With the high-resolution electron microscopes now commercially available, it is possible to obtain resolution in images of crystal lattices of 2Å or better. While this is applied most frequently for obtaining simple fringe patterns from materials having small unit cells, it may also be used to resolve detail within the unit cell of more complicated structures as in figure 1, obtained with a JEM-100B electron microscope at 100kV. We are investigating means for obtaining better images, e.g. by the use of pointed filaments, and are studying the possibility that the details of contrast in such images may be interpreted in terms of the crystal structure.

Since a thin crystal is primarily a phase object, a simple, intuitive interpretation of the contrast is not possible. Calculations of contrast made by Elizabeth Chidzey (1970) using a phase-grating approximation for very thin crystals and a more complete n-beam dynamical theory for thicker crystals have confirmed the strong dependence of the contrast on crystal orientation, crystal thickness and the defocus of the microscope.
Observations on the Structure of Ultramicrotomed Thornel—50 Carbon Fiber
Authors: Phillips V. A. , Hugo J. A. , Roberts B. W.
Published: June 2020

Previous lattice plane observation on high strength carbon filaments has shown a high degree of alignment of the (00.2) basal planes parallel to the filament axis. Most of these observations have been made on thin electron-transparent protrusions from fractures, on fibers ground and dispersed ultrasonically, or through the periphery of corrugated filaments. In all cases the axis of the filament was parallel to the plane of the micrographs. However, in order to arrive at an appropriate 3-dimensional model of the structure, it is necessary to know the arrangement of the packets of planes in the third dimension. The results of Harling, indicated that ultramicrotomy could be used.

Thornel—50 Union Carbide Co. C-fiber, which is made from alpha cellulose (rayon) precursor, was mounted in Araldite for sectioning. Slices cut with a diamond knife were examined in a Philips EM300 microscope at 100 kv.
Determination of Preferred Orientation in Crystals from Surface Diffraction Techniques
Authors: Diggs Isaac W.
Published: June 2020

This paper will examine a method of determining preferred orientation in reflection diffraction specimen without the use of a camera constant for the electron microscope. This method was devised in the absence of being able to find any such method in the literature. The method was used to study the orientation of nickel crystals grown on the faces of Al2O3 substrates. The diffraction work was done with 75kv (.0446A) electrons on a model HU-11 Hitachi Electron Microscope. Diffraction patterns were recorded on a photographic film in such a manner that successive frames showed pattern change as a function of angular displacement (tilt rotation).

If for any surface diffraction pattern, the orientation data of the crystals involved were desired, the following procedure would yield accurate results. The first action is to reproduce the pattern at a convenient size. This can be done by photographic means or by any other means available. Next, the interplanor spacings should be measured for at least three sets of planes which appear in the pattern.
Interaction of Gallium with Copper Surfaces
Authors: Chen Y. T. , Lawless K. R.
Published: June 2020

The interaction of gallium with single crystalline copper surfaces has been investigated by means of high energy glancing angle electron diffraction, transmission microscopy and metallography. Surface structural changes and morphological changes were both recorded. Gallium was deposited in-situ onto both bulk single crystalline copper surfaces and thin film Cu surfaces grown in-situ on (100) NaCl surface inside the HEED apparatus.

Cu-Ga alloy films were observed to grow epitaxially at room temperature on clean (111), (001) and (110) copper surfaces. The epitaxial growth was obgerved only with a deposition rate for Ga of approximately 30 A/min. and on clean copper surfaces. No epitaxial growth of Cu-Ga alloy films was observed on surfaces covered with cuprous oxide. Higher deposition rates always gave diffuse ring type patterns. An early stage ordered ʓ h.c.p. phase was observed to grow on Cu (111) face. A later stage Ø tetragonal phase was observed to grow on all three faces of Cu with three orientations on the (111) face, four major orientations on the (001) face and two orientations on the (110) face.
Precipitation Within a Precipitate—Nickel-Rich Alloys of Nickel, Aluminum and Titanium
Authors: Oblak J. M. , Kear B. H. , Leverant G. R.
Published: June 2020

Figure 1 shows how a precipitate of γ might form within a precipitate of γ' in a given Ni-Al-Ti alloy. The alloy reverts to single phase fcc γ on heating above the solvus temperature TS. Upon aging at T1 an LI2 γ' Ni3 (Al,Ti) phase of composition is formed and is in equilibrium with a γ matrix of composition. . If the alloy is subsequently aged at a lower temperature T2, not only does additional γ' form within the matrix, but γ can also precipitate within γ', provided that the γ' phase boundary is as represented.

In this study a Ni-10.7Al-5.1Ti (at. %) alloy was air cooled from a solution temperature of 2250°F to form coarse γ' particles. The cooling rate was sufficiently rapid that equilibrium was not. achieved at temperatures corresponding to T2 in Figure 1. Samples were then aged for 16 hours at l400°F and their microstructure examined. As evident in Figure 2(a,b), the large γ' particles contained small plate-like precipitates after aging and these appeared to lie on {100} planes.
Microscopical Characterization of Grafted Cotton Fibers
Authors: Goynes Wilton R.
Published: June 2020

Radiation induced graft polymerization of the cellulose of cotton fibers with various other polymers produces textile fibers with new properties. Chemical analysis and physical tests are used to determine changes in such properties as breaking strength, wrinkle recovery angle, and resistance to abrasion. While such tests give reliable evaluations of the overall nature of any improvement, they give little information on what changes actually occurred in the fiber itself. One means of obtaining this information is through microscopical observations.

Penetration and reaction of the polymer within yarns and fibers can be tested by cutting Hardy cross sections of the fibers after they have been dyed with a stain specific for the reacted polymer. More detailed information can be obtained from ultrathin sections, using the transmission electron microscope. Structural changes often occur which are obvious from comparison of cross sections of untreated and treated fibers. Use of the scanning electron microscope permits evaluation of changes in surface features of fabrics and individual fibers.
The Pentalamellar Configuration of the Vertebrate Outer Segment Discs
Authors: Dunn Robert F. , Adomian G. E.
Published: June 2020

With KMnO4 fixation, the pentalamellar disc configuration was observed and considered to result from adhesion of the two membrane elements. Similar five-layered discs were also observed with OsO4 fixation. Cohen has shown that an intradisc space may be present and susceptible to lanthanum infiltration. The cone discs were readily infiltrated by the tracer, and rod discs only in regions of outer segment damage. X-ray diffraction studies have also indicated that a space or region of differential hydration is present in unfixed discs. Whether this is a real or potential space remains unclear, however, it is apparent this is not a membrane fusion. Recent studies on both intact and isolated outer segments have shown the discs are susceptible to intradisc swelling in response to osmotic changes.
Scanning Electron Microscopy of the Choroid Plexus and Ventricular Wall Ependyma in the Rhesus Monkey
Authors: McGrath Philip P. , Clark Ronald G. , Ewell John B. , Wehrung John M.
Published: June 2020

The lumen of the lateral ventricles is separated from the brain parenchyma and the circulatory system by a single layer of specialized epithelial cells, the ependyma. This ependyma is divided into choroid plexus ependymal cells, which coat the pia arachnoid invagination in the lateral ventricles, and the wall ependymal cells which separate the lateral ventricle lumen from brain parenchyma. Using transmission electron microscopy, the ultrastructure of these cells has been described with special emphasis on the difference in apical surface membranes. The apical surface of the choroid plexus ependymal cell contains numerous microvilli and an occasional cilia while the wall ependymal cell contains numerous cilia and only a few microvilli. By scanning electron microscope we have demonstrated differences in the apical surface membrane.

The specimens were fixed in glutaraldehyde by vascular perfusion or infusion into the ventricles and postfixed in osmium tetroxide. They were rinsed in cacodylate buffer and three changes of distilled water, blotted dry, and freeze dried, using liquid nitrogen. They were coated with gold palladium and examined in a Cambridge Mark II A stereoscan, scanning electron microscope.
Differentiation of Ribosomes and Beta Glycogen in Canine Myocardium
Authors: Bishop Sanford P.
Published: June 2020

During the ultrastructural examination of the canine myocardium, it became apparent that the positive identification of specific granules as either ribosomes or β glycogen was very difficult in sections stained with lead citrate and uranyl acetate. In the normal adult canine myocardium ribosomes are not a prominent organelle, but in certain conditions, free ribosomes may become greatly increased in number. Unlike some other species, glycogen and ribosomes are very nearly the same size (200-250 Å) in the canine myocardium. Following glutaraldehyde fixation and epoxy resin embedding there is considerable variation in electron density of glycoen (Fig. 1).

In an attempt to differentiate glycogen from free ribosome particles, myocardial samples from four normal dogs and six dogs with experimental right ventricular hypertrophy were processed 1) according to routine procedure, 2) following autolysis, 3) following diastase digestion and 4) by the periodic acid silver proteinate method of Theiry (J. Microscopie 6:986, 1967).