bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal Surface Deformation and Subsurface Defect Structure: A Microscopy
Correlation Study
Authors: Carpenter R. W. , Wert J. J. , Caldwell S. G.
Published: June 2020

When a metal surface is deformed by indentation, sliding wear or similar
methods, the crystal volume below the surface deformation trace contains an
array of dislocations whose density varies with position relative to the
surface deformation trace. It has been shown earlier that the combined
imaging modes (TEM/STEM and SEM) of an analytical electron microscope permit
convenient and direct correlation between surface deformation markings and
subsurface dislocation arrays in Al.1 In this note we
report observations of deformation induced at room temperature by single
stylus tracks on a Cu-8 wt % Al alloy. The stylus tracks were applied in a
manner similar to that used earlier,1 but the 50 ± 10
mg load was somewhat larger than the earlier one. A typical example of the
substructure observed is shown in Fig. 1. The dislocation density is very
high in the immediate region of the stylus track, which is parallel to the
trace of one set of {111} planes. Two slip traces extending away from the
mark into the undeformed matrix are visible; such traces are common. The
region around the stylus track is shown at higher magnification in Fig. 2.
It can be seen that the dislocations in the long slip traces extending from
the stylus track are nearly all extended, as one would expect for this low
stacking fault energy alloy (γ ≈ 10 ergs/cm2). Numerous
short slip traces beginning to extend from the stylus track are also
visible. The dislocations in the dense walls along the track are also
dissociated to some extent, but are difficult to observe because they are so
closely spaced. The stylus track on the surface of the specimen is shown in
Fig. 3 with the specimen nearly normal to the incident beam and in Fig, 4
with the specimen tilted about 45°. Note the presence of the small particles
on the track; their direct association with the track is most easily seen in
Fig. 4. The sizes of these small particles range from about 50 to 300 nm.
Their origin is speculative at present; they may result from melting of a
surface oxide, or the first stage of surface debris from the wear process.
Note that the presence of these particles is not evident in the TEM
micro-graphs (Figs. 1 and 2). The widths of the dense dislocation array at
the stylus track determined from TEM and the track itself determined by SEM
are in this case nearly equal. The planar slip traces extend large distances
from the track. These results differ significantly from those reported
earlier for Al, in which the subsurface dislocations formed a dense array
several times wider than the surface track, and also in the absence of
planar slip traces extending away from the track. This difference is
attributed to the low stacking fault energy of Cu-8 wt % Al , which should
inhibit cross-slip and tangling near the track.
Precipitation in Irradiated α Cu-Be Alloys
Authors: Kinoshita C. , Mitchell T.E.
Published: June 2020

The precipitation sequence upon ageing of supersaturated α Cu-Be has
been published by many authors. Tlie sequence in highly super-cooled alloys
is: α → GP zone → γ″ → γ′ → γ. The present paper will demonstrate the
precipitation sequence in under- and super-saturated solid solutions under
electron-irradiation in HVEM.
Practical Examples of Point and Space Group Determination in Convergent
Beam Diffraction
Authors: Steeds J.W. , Evans N.S.
Published: June 2020

The high quality of diffraction information generated by convergent beam
electron microscopy provides many ways of arriving at an unambiguous
assignment of a space group to a crystal under investigation. One method of
space group determination involves tilting the crystal to a number of
different zone axes and combining the information derived from each.
However, it is often possible to obtain the same information more
efficiently by concentrating on just one high symmetry zone axis and it is
this approach which will be illustrated here. The prerequisites for the
application of the technique are a good crystal and a microscope which
offers a large angular view of the back focal plane of the objective lens.
Specimen cooling is generally advantageous but has not been used in most of
our work and, in particular, was not used for the results used as
illustrations here. By the term 'good' crystal is meant a homogeneous and
strain-free crystal without planar disorder (stacking faults, antiphase
boundaries) linear disorder (dislocations) or point disorder. The
requirements are certainly stringent but they need only operate over a cube
of side approximately 1OO nm. Point disorder which produces an effect of the
same order of magnitude as thermal disorder can be tolerated and strains
less than 10-4are not detected. An angular view of 20°
or so in the diffraction plane is generally acceptable although a larger
view would be helpful for certain crystal structures and for low-specimen
temperatures.
Critical Voltage Effect in Tungsten ECP
Authors: Farrow R. C , Joy D. C
Published: June 2020

The critical voltage effect is caused by an accidental degeneracy
between two Bloch waves at a certain energy, Vc, and results in a
disappearance of a particular reflection in the Kikuchi pattern. The effect
until now has only been detected in this way via high voltage transmission
electron microscopy, mainly because for most materials Vc is several hundred
keV. Since the predicted critical voltage for the (220) reflection in
tungsten is 22 keV, we attempted, with success, to detect the effect in an
SEM by looking at the tungsten electron channeling pattern (ECP) as a
function of accelerating voltage, E0. The critical
voltage effect was evident in the (220) ECP line as an anomalous narrowing
of the line near Vc and inverted contrast of the line
for E0 > Vc. Vc was determined
by measuring the voltage where the (220) linewidth was at a minimum to be
Vc = 10.50 ± .05 keV. This experimental
Vc was used in a many beam diffraction calculation
to refine the first order Fourier lattice potential coefficient. The shape
of the line narrowing curve in the vicinity of Vc was
used to estimate the depth of ECP information for the (220) line in
tungsten. Details of the experiment and subsequent calculations will be
discussed. The measurements were done on a single crystal of tungsten in a
modified version of an ISI Super III-A scanning electron microscope. The
linewidth of the (220) ECP line was measured in the range 10-15 keV from
specimen current line profiles using a signal gating and averaging technique
to improve the signal to noise ratio. The (220) line becomes too broad to be
visible above 15 keV which is in agreement with line-width calculations
using simple two beam diffraction theory. An example ECP and line profile
are shown in Figure 1 for E0 = 12.25 keV. The
micrograph is a differentiated image of the backscattered electron signal.
The dark (220) line was of opposite contrast to the rest of the (110) series
of lines which were light. The (220) line shape is circled in the line
profile. Its line-width, △θ, is defined as the angular distance between the
maximum and minimum.
Techniques for Imaging Internal Composition and Structure of MN
Micronodules
Authors: Barnard Leo A.
Published: June 2020

Manganese micronodules (Mn accumulations <500 μm diameter found
throughout marine sediments) represent as much as 65-80% of all marine
sedimentary Mn (Chester and Hughes, 1969). Work on marine manganese
occurrences up to the present time has been focused upon nodules (> 1 cm
diameter) found at the sediment-water interface. The economic importance of
nodule associated trace metals explains this restricted approach but does
not aid our understanding of the genetic processes for manganese
accumulation. Micronodules have not been studied with the rigor due a
potential manganese nodule precursor species.
A New Technique in Preparing In Situ Marine Sediments for Clay Fabric
Study
Authors: Chiou Wen-An
Published: June 2020

The study of clay fabric, including the spatial distribution,
orientation, and particle to particle relationship of the solid particles
(< 4 μm) in the sediments, is a subject which has evoked interest over a
long period. However, due to the limitation of both coring devices and
laboratory instruments, no in situ (“real”) clay fabric has been observed,
especially for those deeply buried subsurface sediments in which the clay
fabric may have changed due to release of overburden pressure. This paper
presents a newly developed methodology to delineate the real in situ clay
fabric microfeatures of undisturbed natural sediments obtained using a
pressure core barrel.
A Preliminary Examination of Material Segregation in a Nuclear Waste
Glass
Authors: Howitt D. G. , DeNatale J. F. , McElfresh D. K. , Geiss R.H.
Published: June 2020

The glasses proposed for nuclear waste containment are ideally
homogeneous in their dissolution of the waste components and relatively free
from devitrified products. Incomplete dissolution will likely result in poor
durability arising from the enhanced leachinq of the undissolved waste
materials whilst devitrified products might give rise to interfacial
decohesion and the provision of additional pathways for this same
effect.

A borosilicate glass similar in composition to those put forward as
candidates for commercial nuclear waste containment was combined with a
compatible mixture of simulated waste oxides at 1100°C for five hours. The
resulting glass was annealed for eighteen hours at the maximum
crystallization temperature of the pure glass and then quenched to room
temperature prior to examination by electron microscopy.
Misfit Dislocations in the Ilmenite (FeTiO3)-Hematite
(Fe2O3) System
Authors: Lagerlöf K.P.D. , Heuer A.H. , Mitchell T.E.
Published: June 2020

It has been reported by Lally et. al. [1] that precipitates of hematite
(Fe2O3, space group R3c) in a
matrix of ilmenite (FeTiO3, space group R3) are lens
shaped and flattened along the [0001]-direction. The coherency across the
interface is lost by the introduction of a misfit dislocation network, which
minimizes the strain due to the deviation in lattice parameters between the
two phases [2]. The purpose of this paper is to present a new analysis of
this network.
Ferroelectric Domain Structure of
Pb(Zr.52Ti.48)03
Authors: Goo E.K. , Mishra R.K.
Published: June 2020

Ferroelectric domains are twins that are formed when PZT undergoes a
phase transformation from a non-ferroelectric cubic phase to a ferroelectric
tetragonal phase upon cooling below ∼375°C.,1 The
tetragonal phase is spontaneously polarized in the direction of c-axis,
making each twin a ferroelectric domain.

Thin foils of polycrystalline Pb
(Zr.52Ti.48)03
were made by ion milling and observed in the Philips EM301 with a double
tilt stage.
Information and Dose in the Scanning Transmission Ion Microscope
Authors: T. R. Fox , Levi-Setti R.
Published: June 2020

At an earlier meeting [1], we discussed information retrieval in the
scanning transmission ion microscope (STIM) compared with the electron
microscope at the same energy. We treated elastic scattering contrast, using
total elastic cross sections; relative damage was estimated from energy loss
data. This treatment is valid for “thin” specimens, where the incident
particles suffer only single scattering. Since proton cross sections exceed
electron cross sections, a given specimen (e.g., 1
μg/cm2 of carbon at 25 keV) may be thin for
electrons but “thick” for protons. Therefore, we now extend our previous
analysis to include multiple scattering. Our proton results are based on the
calculations of Sigmund and Winterbon [2], for 25 keV protons on carbon,
using a Thomas-Fermi screened potential with a screening length of 0.0226
nm. The electron results are from Crewe and Groves [3] at 30 keV.
Stem Dark Field Imaging of Deformed Polyethylene Spherulites
Authors: Sherman E.S.
Published: June 2020

The transformation of the spherulitic morphology of polyethylene (PE) to
the fibrous structure during tensile deformation is of fundamental
importance in understanding the mechanical properties of polymers.
Spherulites consist of thin lamellar crystals. The polymer chains are
parallel to the thin direction of the lamellae which is perpendicular to the
spherulite radius. Tensile deformation results in the formation of
micronecks initially in the equatorial zones and along spherulite
boundaries. Figure 1 is a CTEM bright field image of a microneck zone in a
thin (<1000 Å) PE film. The draw direction is vertical. The micronecks
contain the load bearing microfibers that are drawn from the lamellar
crystals. The deformation mechanism has been extensively studied by the
indirect methods of wide and small angle x-ray scattering. Twinning, chain
tilt and slip parallel to the chain axis and finally break up of the
lamellae into mosaic blocks, which are incorporated into the microfibers,
occur as the microneck zones widen (l).
Developments in Techniques for Focusing Charged Particles
Authors: Hawkes P. W.
Published: June 2020

Despite the competition from digital and analogue image processing,
geometrical electron optics remains a very lively and active field and a
proper survey of developments would include aberration correction, studies
of new types of analyser and monochromator, the optics of mirrors and
emission structures, computation of gun properties, aberration theory and
the use of computer algebra, lens optimization, unconventional lens
geometries, and field calculation, and this by no means exhausts the list.
The present account must therefore be selective and is restricted to a few
topics, some chosen because they have been studied by the author, others
because we believe them to be important for the future.
Highspeed Oscillography Using an Sem for Circuit Diagnostics
Authors: Gopinathan Gopal
Published: June 2020

The rapid development in the VLSI technology which is a combination of
process complexity and smaller physical device structures, is making greater
demands of characterisation and functional testing of internal circuit
operations. The state-of-the-art device structures have become much smaller
than the mechanical microprobes that are conventionally used to test
internal nodes and as a consequence the use of such probes to measure
internal signals for either functional or parametric testing is no more
feasible. The submicron devices have also better transient responses and the
parasitic reactance of the mechanical probes present significant loading in
the circuit causing distortion of the measured signals at high
frequencies.
Measurement of The Ultimate Resolution of The Electron Resist Pmma Using
A Stem
Authors: Broers A. N.
Published: June 2020

The resolution that can be obtained in an electron resist layer is
usually determined by electron scattering in the resist layer itself and by
electron back-scattering from the underlying substrate. In order to measure
the resolution in the absence of significant electron scattering very thin
(~ 30nm) resist layers of PMMA1 supported on thin (~
50nm) Si3N4 membrane
substrates2 have been exposed. Under these
conditions, resolution becomes effectively limited only by the basic
physical processes involved in breaking the bonds in the methacrylate
polymer. The probability that electrons will be back scattered from the
resist substrate combination is < 2 × 10-4, and
small angle scattering in the resist will only give rise to scattering
angles less than the beam half angle, i.e. < 10-2
radian.3
Reducing the Proximity Effect in Electron Lithography
Authors: Soqard M.R.
Published: June 2020

When an electron beam is used to expose a resist, neighboring regions of
the resist are also partially exposed. This arises from multiple scattering
of the electrons in the resist and by backscattering of the electrons in
both the resist and (mainly) in the substrate beneath the resist. From
various studies1,2 this non-local energy deposition can
be characterized by a number of regions, There is a very intense energy
deposition, which is typically quite narrow and is produced by the direct
incident beam broadened by multiple scattering in the resist. This is
surrounded by an approximate plateau of intensity of about 1-2 orders of
magnitude weaker, which is produced almost entirely by electrons
backscattering from the substrate. The plateau arises from two conflicting
effects: the backscattering yield drops as we move away from the central
beam, but the mean electron energy also decreases. Therefore the stopping
power increases, thus tending to offset the first effect. Finally this
plateau cuts off fairly sharply at a distance approximately equal to the
Bethe range of electrons in the substrate.
Sub-Micrometer Linewidth Measurement by Electron Microscopy
Authors: Hembree G.G. , Jensen S.W. , Marchiando J.F.
Published: June 2020

Preliminary results are presented for the measurement of sub-micrometer
dimensions of chromium-on-glass lines utilizing a specially modified high
resolution scanning electron microscope. The basis of the measurement is an
interferometrically positioned, piezoelectrically driven scanning stage. In
addition, on-going work in theoretical modeling of the measurement process
is di scussed.
Undissociated Dislocations in Ion Damaged Silicon
Authors: Tan T.Y. , Foell H.
Published: June 2020

Ion implantation in recent years has become an integral part of
fabricating electronic devices in Si, e.g., shallow source and drain pockets
in FET devices may be fabricated by implanting As+ions
at ~ 100 keV to a dose of ~
1016/cm2. For such implanting
conditions, the top layer of the material becomes amorphous and during
subsequent heat treatment it grows back epitaxially into a single crystal
layer containing dislocations. For several reasons dislocations may be
generated in the recrystallized layer. If a high concentration of
substitutional species whose atomic radius is sufficiently different from
the Si atom radius is incorporated, the strain in this layer may exceed the
Si elastic limit and a misfit dislocation network, situated close to the
implanted - unimplanted material interface, may form. Certain implanting
species may tend to form small clusters with Si atoms and thus causing
stacking errors to occur in the growing Si crystal, i.e., dislocations may
now be nucleated within the recrystallized layer. However, it is also known
that V-shaped dislocation half loops form even for Si+
implanted Si.1 They are apparently nucleated from
positions close to the initial amorphous-crystalline Si interface,
indicating that certain dislocation nuclei in the crystalline Si beneath the
amorphous layer were already generated during implantation. We have
presently analyzed the defects in the crystalline material right beneath the
amorphous layer by the lattice imaging technique. Among others, the defects
of primary interest are undissociated 60° dislocation dipoles of small
sizes.
Compositional Analysis of III-V Interface Lattice Images
Authors: Olsen A. , Spence J.C.H. , Petroff P.
Published: June 2020

Since the point resolution of the JEOL 200CX electron microscope is
up = 2.6Å it is not possible to obtain a true
structure image of any of the III-V or elemental semiconductors with this
machine. Since the information resolution limit set by electronic
instability (1) u0 = (2/πλΔ)½ =
1.4Å for Δ = 50Å, it is however possible to obtain, by choice of focus and
thickness, clear lattice images both resembling (see figure 2(b)), and not
resembling, the true crystal structure (see (2) for an example of a Fourier
image which is structurally incorrect). The crucial difficulty in using the
information between Up and u0 is the fractional accuracy with which Af and
Cs must be determined, and these accuracies Δff/4Δf =
(2λu2Δf)-1 and
ΔCS/CS =
(λ3u4Cs)-1
(for a π/4 phase change, Δff the Fourier image period)
are strongly dependent on spatial frequency u. Note that
ΔCs(up)/Cs
≈ 10%, independent of CS and λ. Note also that the
number n of identical high contrast spurious Fourier images within the depth
of field Δz = (αu)-1 (α beam divergence) decreases with
increasing high voltage, since n = 2Δz/Δff = θ/α = λu/α
(θ the scattering angle). Thus image matching becomes easier in
semiconductors at higher voltage because there are fewer high contrast
identical images in any focal series.
Structure Imaging of Faults in Cadmium Telluride
Authors: Ponce F.A. , Yamashita T. , Sinclair R.
Published: June 2020

Multibeam, high resolution imaging has been used successfully by a
number of workers to characterize the nature of defects in various FCC
crystals, such as silicon [1-3], germanium [4] and gold [5]. It has become
conventional in these studies to examine the 110 orientation in which two of
the four {111} type planes are parallel to the electron beam. Under
appropriate experimental conditions, bright spots in the images represent
either the projection of the atomic columns or of the channels in the
structure [6]. For medium resolution imaging (∿ 3Å), there is little
difference between the appearance of the diamond cubic (Si,Ge) and FCC
structures (Au). The present article reports equivalent observations for
cadmium telluride, a compound semiconductor with the related zinc-blende
structure. As with Si and Ge, medium resolution images are not
distinguishable from those of primitive FCC. Higher resolution images are
described elsewhere [7].
Faulted Loops in BF2+-Implanted Silicon
Authors: Chen L.J. , Wu Y.J. , Wu I.W.
Published: June 2020

Formation of faulted loops in silicon either after oxidation or after
annealing of silicon containing oxygen have long been recognized and
investigated. The loops were generally determined to be interstitial in
nature, bounded by ⅓ <111> partials and lying on {111}
planes.
The Structure and Properties of MoSi2 Thin Film in Mos
Process
Authors: Wu C.K. , Chang P. , Godinho N.
Published: June 2020

Recently, the use of refractory metal silicides as low resistivity, high
temperature and high oxidation resistance gate materials in large scale
integrated circuits (LSI) has become an important approach in advanced MOS
process development (1). This research is a systematic study on the
structure and properties of molybdenum silicide thin film and its
applicability to high performance LSI fabrication.
Transmission Electron Microscopic Observations of Al3Li and
Al3Ti Precipitation in A Rapidly Solidified Al-3Li-0.2Ti
ALLOY
Authors: O’Neal J. E. , Sankaran K. K. , Sastry S. M. L.
Published: June 2020

Rapid solidification of a molten, multicomponent alloy against a
metallic substrate promotes greater microstructural homogeneity and greater
solid solubility of alloying elements than can be achieved by slower-cooling
casting methods. The supersaturated solid solutions produced by rapid
solidification can be subsequently annealed to precipitate, by controlled
phase decomposition, uniform 10-100 nm precipitates or dispersoids. TEM
studies were made of the precipitation of metastable Al3Li(δ’) and
equilibrium AL3H phases and the deformation characteristics of a rapidly
solidified Al-3Li-0.2Ti alloy.
A Transmission Electron Microscopical Investigation of Phase
Transformations in TiNi
Authors: Moine P. , Michal G. M. , Sinclair R.
Published: June 2020

Premartensitic effects in near equiatomic TiNi have been pointed out by
several authors(1-5). These include anomalous contrast in electron
microscopy images (mottling, striations, etc. ),diffraction effects(diffuse
streaks, extra reflections, etc.), a resistivity peak above
Ms (temperature at which a perceptible amount of
martensite is formed without applied stress). However the structural changes
occuring in this temperature range are not well understood. The purpose of
this study is to clarify these phenomena.
A Diamond Cubic to Hexagonal Phase Transformation in Silicon
Authors: Tan T. Y. , Foell H.
Published: June 2020

We have detected a Si hexagonal phase in wafers implanted at high dose
rate, P-type, 2-12 Ωcm, <001> oriented Si wafers were implanted by 80
keV As+ ions to a dose of
1016/cm2 at a current of 100
μA. These samples, without further heat treatment, were analyzed by TEM
observations. The hex Si appears as a few hundred Å long rods elongated in
the matrix <110> direction, see Fig. 1. They produce weak but
observable diffraction effects which led to their identification, Fig. 2.
The orientation relationship of the hex and dc Si is that
[000l]hex | | [110]dc and
[1010]hex | | [001]dc. Because
of their small sizes, we could not identify their habit planes. Mechanical
deformation experiments, however, showed that large size hex Si platelets
with {115}dc habit planes may be
produced.2 We have performed such experiments to
confirm this point. We now propose a dc to hex phase transformation scheme
for Si. Assume that the transformation driving force is a large compressive
stress in the dc [110] direction. Then the bond between an atom and one of
its two nearest neighbors on the (110) plane may be broken and a new bond
between this atom and one of its two second nearest neighbors along the
[110] direction may be formed. In this way, six membered atomic rings
appropriate for the hex type structure are formed, Fig. 3(a). Relaxation of
these new rings proceeds simultaneously to give the structure in Fig. 3(b),
which is the hex Si structure with proper orientation relationship w.r.t. dc
Si. After the transformation, the material expanded by ~18% in the
[110]dc direction, contracted by ~18% in the
[110]dc direction. Thus, the transformation
facilitates a stress relieving mechanism which provided a relief of the
equivalent of ~18% of a pure elastic compression in the dc [110] direction.
We estimated that the hex Si is ~109
ergs/cm3 higher in energy than the dc Si, and an
activation energy of ~1011
ergs/cm3 is needed to induce this transformation.
We have also constructed an atomic model for the dc-hex Si interface, the
(115) habit plane. This interface is composed of 5-7 membered atomic rings
with no dangling bonds or long range strains and it is therefore a low
energy configuration, Fig. 4. Hexagonal Si were generated in ion implanted
samples, we believe, because of direct transfer of momentum from the the
impinging ions provided enough energy to overcome the nucleation barrier.
Once they are generated, stress provided by dislocations and amorphous zones
stabilized the transformed regions.
Observations of The Interface Phase in α+β Ti Alloys
Authors: Chen C. , Williams J. C.
Published: June 2020

The α/β interfaces have been shown to be an important factor in the
fracture behavior of Ti alloys, since they are crack paths in tensile and
fatigue fracturen[1,2]. A possible reason for these interfaces being a
fracture path is the presence of a third constituent between the α and β
phases. This has been called interface phase[3], and it has been reported
that this phase forms with either a fee or hep structure. This phase does
not grow isothermally, but grows only during cooling from elevated
temperatures >1000°C to about 650°C in Ti-6A1-4V[4]
Phase Identification in Neutron Irradiated Stainless Steels
Authors: Lee Eal H. , Rowcliffe A. F.
Published: June 2020

Currently, AISI 316 stainless steel is widely used as a structural
material for fast reactor core components. This material is susceptible to
void swelling during irradiation at temperatures in the range 400 to 650°C.
The nucleation and growth of radiation-induced voids are structure sensitive
phenomena and are strongly affected by the nature and morphology of phases
which develop during irradiation, the chemical composition of the matrix and
the dislocation density. To understand the mechanisms of void swelling and
to eventually develop materials with greater resistance to these phenomena,
it is important to correctly determine the structure and composition of the
phases which develop during irradiation of these complex alloys.
Observations of Gas Bubbles in an Austenitic Stainless Steel Charged
with3H
Authors: Sklad P. S.
Published: June 2020

Nitronic 40 is a high-strength austenitic stainless steel.
Investigations are in progress to explore the possibility of using this
material as a high-strength substitute for 300 series stainless steels,
especially in hydrogen environments. There is also interest in determining
the influence of helium on the mechanical properties of this material from
the viewpoint of fusion reactor systems. The alloy is nominally (in weight
percent) 21 Cr, 6 Ni, 9 Mn, and 63 Fe and is strengthened by 0.35 wt %
N.

Smooth bar tensile specimens approximately 3.5 mm in diameter with 25 mm
gage lengths were machined from high energy rate forged (HERF) stock. These
specimens were then gas phase charged with 2H at 64 MPa
pressure at 470 K or 3H at 47.5 MPa at 345 K for 1450
h. Due to the nature of the charging the 3H
distribution was nonuniform, ranging from approximately 1300 ppm at the
specimen surface to less than 5 ppm at a depth of 0.5 mm from the surface.
Following charging, the specimens were stored at ˜250 K for 5.5 years.
Approximately one-third of the tritium decayed to 3He
during this period, yielding a maximum of 900 ppm of
3He at the surface of the specimens. Tensile tests at
298 K revealed a significantly greater loss in ductility in the specimens
charged with 3H. Following tensile testing TEM
specimens of suitable size were sectioned near the fracture surface, thinned
using conventional techniques for radioactive specimens, and examined.
Electron microscopy was performed in a Philips EM 400T equipped with a field
emission gun.
TEM Analysis of Printed Circuit Board Copper Foil
Authors: Anderson Ron , Wild Roger
Published: June 2020

Approximately two years ago, electro-deposited (ED) copper foil cracking
was noticed when testing relatively high density, highly stressed multilayer
boards (MLBs) to the rigid 55()°F thermal stress test requirements of
MIL-P-55640 and eventually MIL.-P-551 IOC. This ED copper foil cracking is
basically caused by severe plated through hole (PTH) bending forces caused
by the large difference in thermal expansions between the copper PTH barrel
and the epoxy glass resin within the multilayer board at high soldering
lemperatures. The severity of the copper foil cracking would be dependent on
the basic thermal mismatch of MLB materials; the severity of thermal
exposure; the specific design impacts; and the mechanical properties of the
copper foil. Copper foil cracks develop circumferentially around the PTH
barrel within the relatively weak columnar grain boundaries of the ED copper
foil. Generally, cracks occur quite close (within 2 mils) of the PTH barrel
wall with cracking or fracturing being more dominant on the first and last
internal foil layers within the board.
Preparation of Thin Graphite Supporting Films
Authors: Crewe A. V. , Mittleman R. K. , Rosman R. L.
Published: June 2020

One of the principal limitations of high resolution microscopy is the
nature of the substrates which are used. In particular it is important that
the substrate upon which the specimen sits not limit the resolution of the
microscope.

There are two requirements which the substrate must fulfill. First of
all it must be free of diffusible hydrocarbons and heavy atom contaminants.
Secondly it must be flat and uniform over a large area. These criteria are
met by thin crystals such qs graphite. Such crystals will, unlike amorphous
substrates, produce uniform background signals which can be sub-stracted
from the overall signal.
Effects of Modulating Fibronectin Levels on the Organization Of Submembrahous Microfilaments, and the Formation of Stress Fibers in Fibroblasts
Authors: Singer Irwin I.
Published: June 2020

Stress fibers are muscle-like organelles containingnumerous 50-70A dia. actin microfilaments, usually found in mammalian fibroblasts. Their ends anchor in the adhesion plaques of the cell membrane which are in close proximity to the substrate and apparently attach the cell to it (1). Many tumorigenic cells often lack or contain sparse stress fibers of diminished thickness (2). Information concerning the mechanics of stress fiber formation and the control of their attachment to membranes is therefore crucial for understanding how normal cells move, in vitro, and how metastatic cells invade adjacent tissues in vivo.
Scanning Electron Microscopy And X-Ray Microanalysis of Foreign Bodies
Associated with Polydimethylsiloxane (PDS, SILASTIC) Implants in
Humans
Authors: Tatum A.H. , Shelburne J.D. , Ingram Peter
Published: June 2020

Polydimethylsiloxane (silastic) membranes possess the very useful
property that steroid hormones diffuse through them at slow predictable
rates. This characteristic has been utilized in clinical studies of
contraception by the subcutaneous implantation of PDS capsules containing
the progestational agent megestrol acetate. When tissues surrounding these
implants were studied by histologic methods, a granulomatous foreign body
reaction characterize by multinucleated giant cells and birefringent
crystals was seen. Several authors have interpreted this birefringent
material as steroids that diffused out of the capsules and reformed as
crystals in the subcutaneous tissue. Since this tissue had been processed by
paraffin embedding, which includes treatment with ethanol and xylene, the
persistance of steroid crystals seemed unlikely. Indeed, studies in our
laboratory showed: first, that megestrol acetate crystals implanted in
autopsy-obtained subcutaneous tissue were removed by routine organic solvent
dehydration, and second, that the crystals in tissue sections from implant
patients persisted in spite of organic solvent treatment known to dissolve
megestrol acetate.
Early Foreign Body Reaction in the Mouse Lung to Intravenously Injected
Polymer Beads
Authors: Coleman S. E. , Hood C. I. , Schoen F. J. , Robinson M.
Published: June 2020

The local interaction between biomaterials and host tissue is important
in a number of problems involving surgically implanted medical devices. The
foreign body reaction (FBR) is typically studied by surgical implantation,
but it is difficult to distinguish the differences between surgical trauma
and FBR, especially after short implantation times. In particular, surgical
implantation models preclude mechanistic inferences as well as qualitative
and quantitative assessment of fine differences in biocompatibility among
materials.

To develop a non-surgical model for FBR, divinyl benzene copolymer beads
(Biobeads SX-8, BioRad) were injected into the tail vein of mice, embolizing
to the lung. We observed granuloma development over periods of 5 minutes to
1 year. Each animal was injected with 10,000 Biobeads (average diameter,
0.005 cm). After intervals of 5 minutes; 3, 6, 12, 24 and 48 hours; 4 and 8
days; 6 and 16 weeks; and 1 year, the animals were sacrificed, the lungs
perfused per trachea with glutaraldehyde-paraformaldehyde fixative and
prepared for light and electron microscopy.
Stereological Analyses of Hepatocyte Ultrastructure Monitor Arsenic Liver
Burdens
Authors: B. Sorensen E. M. , Mitchell R. R. , Graham L. L.
Published: June 2020

Endemic freshwater teleosts were collected from a portion of the
Navosota River drainage system which had been inadvertently contaminated
with arsenic wastes from a firm manufacturing arsenical pesticides and
herbicides. At the time of collection these fish were exposed to a
concentration of 13.6 ppm arsenic in the water; levels ranged from 1.0 to
20.0 ppm during the four-month period prior. Scale annuli counts and prior
water analyses indicated that these fish had been exposed for a lifetime.
Neutron activation data showed that Lepomis cyanellus (green sunfish) had
accumulated from 6.1 to 64.2 ppm arsenic in the liver, which is the major
detoxification organ in arsenic poisoning. Examination of livers for
ultrastructural changes revealed the presence of electron dense bodies and
large numbers of autophagic vacuoles (AV) and necrotic bodies (NB) (1), as
previously observed in this same species following laboratory exposures to
sodium arsenate (2). In addition, abnormal lysosomes (AL), necrotic areas
(NA), proliferated rough endoplasmic reticulum (RER), and fibrous bodies
(FB) were observed. In order to assess whether the extent of these cellular
changes was related to the concentration of arsenic in the liver,
stereological measurements of the volume and surface densities of changes
were compared with levels of arsenic in the livers of fish from both
Municipal Lake and an area known to contain no detectable level of
arsenic.
Marburg-Like Virus: Ultrastructural Observations of an Isolate from
Kenya, 1980
Authors: Whitfield Sylvia G. , Regnery Russell L. , Elliott Luanne H.
Published: June 2020

In February of this year specimens were sent from the Medical Research
Center, Nairobi, Kenya to the Center for Disease Control (CDC), Atlanta,
Georgia for isolation and identification of an agent responsible for a
particularly severe disease clinically suggestive of a viral-induced
hemorrhagic fever. Formalin-fixed liver biopsy from an acutely ill patient
was sent for microscopic examination. Serum from this patient had been
inoculated into Vero (continuous cell line derived from Ceropithecus
aethiops) cell culture at the Medical Research Center. This cell culture
material was further passaged in Vero cells upon receipt at the Maximum
Containment Laboratory (MCL) of the CDC. For negative contrast examination,
virus was purified from the cell supernatant fluids of the 3rd passage,
3-day postinfected Vero cells. For thin-section examination virus-infected
Vero cells were prepared by gently scraping cells from a 3rd passage, 4-day
postinfected cell culture, washing the cells in phosphate buffered saline,
and pelleting the cells at 500Xg for 5 minutes in 2.5% buffered
glutaraldhyde. The cell pellet was fixed In 2.5% buffered glutaraldehyde for
72 hours before it was processed and embedded for electron microscopy
(EM).
Cystoid Degeneration of Mouse Pituitary – Ultrastructural Study
Authors: Andrews Annette M. , Cameron Alex M. , Townsend James W. , Sheldon Winslow G.
Published: June 2020

Pituitaries of 6 C3H/HEJ MTV+ mice about 660 days of age were fixed by
immersion in cacodylate-buffered 4% glutaraldehyde, post-fixed in 1% osmium
tetroxide, stained en block with aqueous uranyl acetate, dehydrated in a
graded series of ethanol solutions, cleared in acetone, and embedded in an
Epon-Araldite resin mixture. Semi-thin (1 μm) sections were taken of the
entire face of the block, and stained with toluidine blue. Subsequently,
thin sections (100 nm) were prepared from mesas of the two sides of the pars
distal is and one mesa of the pars intermedia. Thin sections were stained
with ethanolic uranyl acetate followed by Sato's lead citrate (1), then
examined on a Philips EM201 electron microscope.
A Comparative Study of Hydrosalpinx
Authors: Patton Dorothy L.
Published: June 2020

Hydrosalpinx, a pathological condition which causes infertility in
women, is characterized by occlusion of the distal end of the fallopian
tube, and a dilation of the tube with fluid. Little is known regarding the
development of hydrosalpinx and the accompanying morphological changes. To
investigate specifically the effect of chronic tubal distention on structure
and function of the oviduct, hydrosalpinges were induced in rabbits and
monkeys by ligating the fimbriated end of the oviduct. Subsequent fluid
accumulation in the distal half of the tube (ampulla) caused a gradually
increasing distention that reached a maximum diameter of about 3 times
normal size in 4-6 weeks. The dilated tubes were removed 1 to 5 months
following ligation for both morphological and physiological examination.
Contralateral tubes were used for controls. Scanning electron microscopy of
the luminal surface of the ampulla of both species revealed a striking
decrease in the large mucosal folds that normally fill the lumen of the
oviduct and run longitudinally in parallel throughout the length of the
ampulla. Smaller ridges formed an interlacing network between the much
reduced primary mucosal folds (Fig. 1). The epithelial surface of the lumen
contained secretory and ciliated cells which were normal in their appearance
and distribution (Fig. 2).
Can Myocardial Cellular Hyperplasia be Produced in Hearts of Adult Dogs
By Electronic Pacing?
Authors: Adomian G. E. , Osborne S. , Laks M.
Published: June 2020

As demonstrated in the pulmonary arterial banded heart, myocardial cell
size increases concomitantly with ventricular weight. However, in some dogs
cell size did not parallel the increase in weight. This disparity may have
been due to edema and/or fibrosis. Although not considered to occur in the
adult heart, myocardial cell hyperplasia may be the important cause of the
disparity. Therefore the aim of this study was to test the hypothesis that
myocardial cell size may not always increase concomitantly with ventricular
weight.

Arterioventricular block was produced in 14 adult mongrel dogs by the
Beazell technique in which a transvenous electrode catheter is utilized to
electrocoagulate the AV node without thoracotomy (1,2).Apical right
ventricular pacing catheters were used to electronically pace the heart at
70 bpm for 4-60 months. From the paced and normal groups, matched samples
were obtained from the left ventricular base and processed in Epon 812 for
microscopy. Cell length and width were measured on 1100 cells.
Acid and Alkaline Phosphatase Activity in Axenically Grown Physarum
Myxamoebae
Authors: Aldrich Henry C.
Published: June 2020

In preparation for biochemical studies of isolated plasma membranes of
myxamoebae of the mycetozoan Physarum polycephalum, histochemical studies
were undertaken to determine the cellular localization of alkaline and acid
phosphatase activities. In a previous paper, Kazama and
Aldrich1 showed that myxamoebae of Physarum, when
grown with E. coli as the food source, synthesize acid phosphatase in Golgi
apparatus and utilize it in food vacuoles in the process of bacterial
digestion. There are no data, however, regarding whether myxamoebae grown on
an axenic medium secrete and sequester acid phosphatase within the food
vacuoles. One purpose of this study was to answer this question. Secondly,
alkaline phosphatase is a commonly used marker for plasma membranes in
mammalian cells and is often employed in cell fractionation studies. Its
presence in plasma membranes of Physarum myxamoebae has not been
demonstrated, so the study reported here was also designed to see whether
alkaline phosphatase occurs in these intact cells, and if so,
where.
Ultrastructural Studies on an Unidentified Microorganism in Urine
Authors: Sun C. N. , Morgan P. N. , Herring F. , White H. J.
Published: June 2020

We recently studied the fine structure of unusual microorganisms in a
urine specimen. To our knowledge, previous electron microscopic
investigation of these microorganisms has never been done.

The microorganisms were found in the sediments of two separate urine
specimens obtained from a 55 year old patient. In these samples, there were
yeast cells and two types of gram negative microorganisms; a typical
rodlike, non-mobile bacterium, and a spheroid form with two projections. The
latter organisms were varying sizes and moved by a typical serpent-like
motility. The rod-like structures were approximately 0.4 - 1 μ in diameter
and up to 8 μ in length. The spheroid structures, which stained
homogeneously and were not spore-like in appearance, were approximately 6 μ
in diameter. A few intermediate or transitional forms of various sizes and
shapes were also found.
A Study of Kinetoplast DNA in Trypanosoma Equinum
Authors: Cuthbertson Robin
Published: June 2020

Members of the Protozoan Order Kinetoplastida are characterized by the
presence of a unique organelle called the kinetoplast. The kinetoplast, a
Feulgen-positive granule, is an integral part of the single mitochondrion of
these flagellates and contains a large amount of deoxyribonucleic acid (DNA,
Fig. 1). Dyskinetoplasty, an apparent disruption of the kinetoplast DNA
(kDNA), occurs spontaneously at low frequency in different species of
Kinetoplastida, and can be induced experimentally with various
DNA-complexing compounds (1). Ultrastructural studies of the equine pathogen
Trypanosoma equinum, a naturally occuring totally dyskinetoplastic species,
were undertaken to determine the possible presence, morphology, and location
of kDNA within the mitochondrion.
An Ultrastructural Analysis of the Lipid Bodies of Trigonella Foe
Num-Graecum
Authors: Gacek Walter F.
Published: June 2020

Ultrastructural cyfochemical studies were conducted on dry seed
cotyledons of fenugreek (Trigonella foenum - graecum)to determine the
composition of the lipid storage bodies. These seeds are used as an
industrial source of steriods which are extracted with hexane. These lipids
have been analysed to be in the glycoside form (1). Lipid solvent extraction
methods were coupled to periodate oxidation methods (2) at the
ultrasctructuraI level to determine the position of components having both
lipid and saccharide characteristics.

Normally dry cotyledon storage cells fixed by conventional electron
microscopic methods show numerous large protein bodies that occupy most of
the cellular volume. Surrounding these bodies, there are numerous tightly
packed lipid bodies (Fig. 1). Plastids with plastoglobuli may also be found
in the surrounding cytoplasm (Fig. 3). Dry cotyledons which are stored in
diethyl ether at room temperature for 2 weeks and subsequently processed for
electron microscopy show a loss of the lipid bodies which surround the
protein bodies (Fig. 2). Acetone and hexane were not as efficient in lipid
removal.
Electron Microscopic Analysis of active and Repressed Chromatin within
Normal and Neoplastic Human Cells
Authors: Frenster J. H.
Published: June 2020

Chromatin within the nuclei of animal cells consists of DNA molecules in
non-covalent association with such intra-nuclear macromolecules as histones,
acidic proteins, lipoproteins, and RNA species (1). These associated ligands
and counter-ligands direct the molecular conformation and biological
activity of DNA molecules within intact cell nuclei and within the intact
chromatin complexes that can be isolated from such cell nuclei (2).

Two major phase states of chromatin are recognized by ultrastructural,
bio-synthetic, and biophysical criteria, and these two states of chromatin
contain DNA template molecules that are either active in or repressed for
RNA synthesis (3). DNA template molecules active in RNA synthesis are found
within extended euchromatin microfibrils (Chart 1) which contain increased
amounts and kinds of acidic proteins, lipoproteins, and RNA species. Each of
these molecular species Is capable of activating for RNA synthesis the DNA
molecules within repressed heterochromatin (Chart 1). By contrast, the DNA
molecules within condensed heterochromatin are found to be repressed for RNA
synthesis (3), and such repressed heterochromatin is relatively devoid of
acidic proteins, lipoproteins, and RNA species.
Characterization of a Motile Cellular Domain Arising During the
Amoebo-Flagellate Transformation of Physarum Polycephalum
Authors: Pagh K.I. , Adelman M.R.
Published: June 2020

Unicellular amoebae of the slime mold Physarum polycephalum undergo
marked changes in cell shape and motility during their conversion into
flagellate swimming cells (l). To understand the processes underlying motile
activities expressed during the amoebo-flagellate transformation, we have
undertaken detailed investigations of the organization, formation and
functions of subcellular structures or domains of the cell which are
hypothesized to play a role in movement.

One focus of our studies is on a structure, termed the “ridge” which
appears as a flattened extension of the periphery along the length of
transforming cells (Fig. 1). Observations of live cells using Nomarski
optics reveal two types of movement in this region:propagation of
undulations along the length of the ridge and formation and retraction of
filopodial projections from its edge. The differing activities appear to be
associated with two characteristic morphologies, illustrated in Fig.
1.