bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoanalysis of impurity precipitation on grain boundaries in polysilicon
Authors: Kim M.J. , Carpenter R.W. , Schroder D.K. , Wohlgemuth J.H. 
Published: June 2020

Polycrystalline silicon (polysilicon) has been the subject of extensive studies in recent years due to its wide applications in microelectronics and solar cells, see for example references. In most cases of interest impurities segregated to the grain boundaries strongly modify the electronic properties of this material. Understanding the behavior of impurities in polysilicon requires a detailed knowledge of their distribution, phase and thermodynamical stability. In the present study, the structure and chemistry of grain boundaries in polysilicon were characterized by HREM and very high spatial resolution FEG/AEM.The specimen materials are Solarex cast polysilicon used for solar cells, which are manufactured under a proprietary method called the ubiquitous crystallization process. The samples for TEM observations were cut from the ingot perpendicular to its growth direction and then thinned to electron transparency by mechanical polishing and ion milling. HREM was performed at 200kV in an ISI-002B. Microanalysis was done using a Philips 400ST/FEG microscope coupled to a Gatan parallel-detection electron energy loss spectrometer, at 100kV. A liquid nitrogen cooled specimen holder was used for nanoprobe experiments to minimize specimen contamination and local specimen heating.
TEM characterization of phosphorus-implanted silicon
Authors: David Theodore N. , Knoch Lynnita , Christiansen Jim 
Published: June 2020

Implantation of dopant-species into silicon can result in the formation of amorphous regions, interfaces and extended defects (in the silicon). The presence of these defects can cause modification of dopant distributions, and the rise of leakage currents in p-n junctions. An understanding of the behavior of implant-induced defects and their effect on dopant-distributions is therefore relevant. Such understanding could lead to better defect and dopant control and therefore to more reliable device performance. In this study, a correlation between dopant distributions and damage in implanted silicon, is investigated.The samples investigated were p-type (14-20 Ω-cm) silicon (100) wafers implanted with phosphorous at 180 kev to a dose of 1x1016 cm-2. The implants were performed at room temperature. Post-implant annealing was performed (by rapid-thermal annealing “RTA“) at 800°C for 15 seconds. SIMS (secondaryion mass-spectrometry) and XTEM (cross-section TEM) analysis were performed on as-implanted and annealed samples. Cross-section TEM specimens were made in the 110 geometry. TEM investigation was performed using a JEOL JEM 200CX transmission electron microscope operating at 200 kV. SIMS analysis was performed using an Atomika A-DIDA quadropole instrument with 8 keV O2+ primary ions.
An Electron Optician's View on the Electron Microscope
Authors: LePoole J. B. 
Published: June 2020

This is the part, that decides the image quality of the microscope. For good resolution, the aperture angle should be as large as possible. Since the important lens errors increase rapidly with the aperture angle, the design should aim a reduction of the errorcoefficients.A good way to reduce these coefficients is to increase the excitation (Ampère turns). Nowadays all objective lenses are designed for high excitation. It means that prevention of saturation anywhere in the ironcircuit plays an important role in the design. It can be shown that by using a symmetric magnetic circuit the excitation of a lens can be approximately doubled without additional problems.
A High-resolution electron microscopy study of Rh/Ce on silica
Authors: Krause K. R. , Schmidt L. D. , Schabes-Retchkiman P. S. 
Published: June 2020

Rhodium is responsible for the catalytic removal of NOx from automobile exhaust and along with other metals, is found in modern catalytic converters. Cerium is an important additive to these catalysts and has been suggested to promote the water-gas shift reaction, to provide oxygen storage, and to improve the thermal stability of the support. We have examined the microstructure of Rh/Ce on silica with several techniques and present results from HREM which provide direct evidence of interaction between Ce and Si in these catalysts.Planar SiO2 supports were prepared by vacuum depositing ∼20nm of Si on formvar coated gold TEM grids and heating the grids in O2. Rh and Ce were then vacuum deposited on the SiO2 and the grids were heated in H2 at 650°C to disperse the film into particles. The microstructures were examined with TEM. The samples were then heated in O2 at 650°C and the same areas were again examined with TEM.
Observation of in situ reduction of ceria-supported rhodium catalysts by electron beam irradiation
Authors: Pan M. 
Published: June 2020

In rhodium catalysts supported on lanthanide oxides, significant difference in rhodium dispersions has been observed between cerium dioxide (CeO2) and sesquioxides (Ln2O3) by high resolution electron microscopy (HREM). This has been attributed to the different behaviors of the oxide supports during their impregnation with aqueous solution of rhodium nitrate (Rh(NO3)3). In the acid media, cerium dioxide has a higher reducibility while the sesquioxides have a higher solubility. So studying the catalyst precursor and the reduction process can provide an understanding of its interaction with the support during the impregnation stage and the metal dispersion on the oxide supports. Results on cerium dioxide support are presented here.The catalyst precursor was prepared by incipient wetness impregnation method as reported elsewhere. The rhodium loading was 2.4 wt%. The HREM work was performed in JEOL 4000EX electron microscope (point resolution of 1.7 Å). The typical current density used during observation was ∼6.5A/cm2 at the specimen. The vacuum in the column of the microscope was ∼10-7 torr.
Advances in microscopy of polymers: A FESEM and STM study
Authors: Chen R.T. , Jamieson M.G. 
Published: June 2020

Microscopy has played a major role in establishing structure-process-property relationships in the research and development of polymeric materials. With advances in electron microscopy instrumentation (e.g., field emission SEM - FESEM) and the invention of new scanning probe microscopes (e.g., scanning tunneling microscope - STM), resolution of structures or morphologies down to the nanometer scale can be achieved with ease. This paper will focus on the application of FESEM and STM in order to understand the structure of commercial polymeric materials. Characterization of polymers using other microscopy techniques such as TEM, thermal optical microscopy and atomic force microscopy (AFM) will also be discussed.The polymeric materials evaluated in this study include membranes, liquid crystalline polymer (LCP) fibers, multiphase polymer blends and polymer films or coatings. In order to minimize beam damage and maximize contrast for surface detail in beam sensitive polymers, low voltage SEM (LVSEM) was performed on a JEOL 840F field emission SEM.
Variations in Mitochondrial Reaction Products From 3,3'-Diaminobenzidine Oxidation At Various Ph Values
Authors: Allen Shannon W. , Hoshino Yoshinobu 
Published: June 2020

Since the initial demonstration of cytochrome oxidase via cytochrome c with 3,3'-diaminobenzidine by Seligman et al. (1), numerous investigations using the technique have been reported. This report deals with incubating media pH variations and resulting characteristics of DAB oxidation reaction product deposition. In addition the localization of initial reaction foci, viz. active sites, was attempted by these variations.Small slices of rat liver were rinsed in 0.05M phosphate buffer-7.5% sucrose (pH 7.0, 4°C), minced, rinsed again and immediately incubated 15 min to 1 hr at 22°C. The medium consisted of 10 ml 0.1M Tris-HCl buffer containing 5 mg of DAB-4 HC1. The range of pH tested was from pH 6.8 to 9.6. The specific pH values tested were 6.8, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0, 8.2, 8.4, 8.6, 9.0, and 9.6. Following incubation, the tissues were rinsed in buffer solution and osmicated 1 hr at 22°C in 2% osmium tetroxide.
The Effect of Vitamin A on the Intermittent Nitrogen Dioxide Gas Exposure in Hamsters
Authors: Kim J.C.S. , Jourden M.G. , Carlisle E.S. 
Published: June 2020

Chronic exposure to nitrogen dioxide in rodents has shown that injury reaches a maximum after 24 hours, and a reparative adaptive phase follows (1). Damage occurring in the terminal bronchioles and proximal portions of the alveolar ducts in rats has been extensively studied by both light and electron microscopy (1).The present study was undertaken to compare the response of lung tissue to intermittent exposure to 10 ppm of nitrogen dioxide gas for 4 hours per week, while the hamsters were on a vitamin A deficient diet. Ultrastructural observations made from lung tissues obtained from non-gas exposed, hypovitaminosis A animals and gas exposed animals fed a regular commercially prepared diet have been compared to elucidate the specific effect of vitamin A on nitrogen dioxide gas exposure. The interaction occurring between vitamin A and nitrogen dioxide gas has not previously been investigated.
Ultrastructural Morphology of two Sensilla Placodea on the Antenna of a Parasitic Wasp
Authors: Barlin Margaret R. 
Published: June 2020

Females of the wasp Tetrastichus hagenowii (Hymenoptera: Chalcidoidea) lay their eggs in cockroach egg cases, the young hatch and feed on the cockroach eggs. Prior to egg deposition the parasites follow a complex behavioral sequence, including tapping their antennal tips on the eggcase, thus enabling them to detect various mechanical and chemical properties of the cockroach egg case and determine its suitability for oviposition (unpublished data).Sensory sensilla occur along the entire length of the female antenna (Fig. 1). Two of the more prominent sensilla were studied by scanning and transmission electron microscopy, these are both sensilla placodea (PI and P2 in Figs. 1 and 2) which are chemoreceptors (1). Numerous hair-like sensilla (H) and a few bulb-like sensilla (B) are also present (Figs. 1 and 2). Sensilla placodea occur frequently on hymenopteran antennae (1), but the occurrence of two types on the same insect has not been reported previously.
Electron Microscopy of Extraskeletal Neoplasm Resembling Ewing's Sarcoma
Authors: SUD B. N. 
Published: June 2020

Review of 39 cases of sarcomas involving soft tissues, especially of the lower extremity and paravertebral region of children and young adults, disclosed a uniform histologic picture that was indistinguishable from that of Ewing's sarcoma of bone (1). Biopsy of a soft tissue tumor of the right thigh of a ten year old boy was studied by light microscopy and diagnosed as poorly differentiated sarcoma, probably extra skeletal Ewing's sarcoma (2). A portion of the biopsy was processed for electron microscopy to elucidate the ultrastructural pathology.The specimen revealed a neoplasm, consisting of sheets of viable as well as necrotic tumor cells. The viable cells had a single large rounded, oval or kidney- shaped nucleus with one or more dense nucleoli and chromatin with occasional clumping along the periphery and also in the interior.
Adrenocortical Ultrastructure in Ectopic Acth Syndrome
Authors: Kovacs K. , Horvath E. , Singer W. 
Published: June 2020

Secretion of ACTH by non-pituitary neoplasms is recognized with increasing frequency. While the clinical and biochemical changes associated with ectopic ACTH production have been extensively studied recently, relatively little attention was focused on the morphology of the adrenal cortex and, to our knowledge, the fine structure of the adrenocortical cells in cases of ectopic ACTH syndrome has not been described so far. We report here the electron microscopic findings in the adrenal cortex of a 50-year-old man with a pancreatic apudoma. The patient showed the characteristic clinical and biochemical features of ectopic ACTH syndrome and because of extensive hypercorticism, underwent bilateral adrenalectomy.By light microscopy, the adrenal cortices showed extensive compact cell hyperplasia and lipid depletion. The zona glomerulosa was present in small foci and, except for a few places, fasciculata cells were noted under the fibrous capsule.
Ultrastructural Characterization of a Murine Squamous Cell Carcinoma (Nettesheim) Induced by 3-Methyl-Cholanthrene
Authors: Liss R.H. , Ifrim I. , Wodinsky I. , Nettesheim P. 
Published: June 2020

An invasive squamous cell carcinoma induced in the trachea of inbred mice by repeated intratracheal injection of the polycyclic hydrocarbon, 3- methyl-cholanthrene, is transplantable and exhibits stable morphological characteristics on repeated passage (1). The neoplasm is of current interest as a quantitative assay for testing new lung cancer therapies and for investigating the effects of host factors on the growth of respiratory tract neoplasms (2).The ultrastructure of the neoplastic tissue implanted subcutaneously in DBA/2 mice was examined 14 and 21 days after inoculation. The tissues were fixed in Karnovsky's fixative (2) and processed for electron microscopy. 60-100 mu sections were obtained with a Porter Blum MT-2B Sorvall microtome, stained with uranyl acetate and lead citrate, and viewed with a Philips 201 electron microscope.
Electron Immunochemical Labeling of Ultrathin Sections of Murine Tumor Viruses and Cell Cultures using the Unlabeled Antibody Enzyme Technique
Authors: Hamilton W. J. 
Published: June 2020

The study of RNA tumor viruses has been greatly facilitated by the use of immunochemical tagging methods. In the past these methods have been constrained to antibody conjugates with ferritin or peroxidase. In order to avoid the disadvantages of using conjugated antisera, investigators have applied the unlabeled antibody enzyme method of Sternberger to mammary tumor derived mouse cells prior to embedding for electron microscopy. The current study has successfully applied the Sternberger method to virusproducing cells and purified virus pellets after epoxy-embedding and ultrathin sectioning. The results demonstrate the distinct advantages of this “post-embedding” method for viral antigen localization.Purified Rauscher leukemia virus (RLV) and mouse mammary tumor virus (MMTV) were pelleted, fixed in buffered 2% paraformaldehyde and washed thoroughly. These were dehydrated in acetone, infiltrated and embedded in Spurr resin according to common procedures. A tumor derived cell line, Mm5mt, producing MMTV was embedded by parallel methods.
Immunoperoxidase Localization of Sindbis Virus Antigen in Infected Vertebrate and Infected Mosquito Cells
Authors: Thomas Virginia L. , Stollar Victor 
Published: June 2020

The localization of Sindbis virus (SV) antigen in infected BHK-21 and infected Aedes albopictus (AA) mosquito cells has been studied using the immunoperoxidase technique.The method of Dougherty et al (1972) as modified and described elsewhere (Thomas & Stollar1974)was used. The cells were seeded and infected on 8 chamber Lab-Tek tissue culture slides (Lab-Tek Division, Miles Labs., Inc.). The immunoperoxidase reaction was also carried out on these slides. Non-specific staining was reduced by exposure of the fixed cells to diluted fetal calf serum before reaction with the anti-SV globulin.Light microscopy (LM) was used to evaluate the reactions before continuing with electron microscopy (EM). The control (uninfected) cells as seen by LM are not shown due to lack of space. Reaction with the anti-SV globulin in the BHK-21 cells shows localization of the viral antigens predominantly in the perinuclear regions, with small foci of more darkly stained material also visible in the cytoplasm of the infected cells, Fig. 1.
Sem and X-Ray Analysis of Renal and Biliary Calculi
Authors: Narconis R. J. , Johnson G. L. 
Published: June 2020

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.
A Simplified Procedure for Embedding Dilute Suspensions of Biologic Material.
Authors: Pfister R.M. , Hanson J.M. , Smucker R.A. 
Published: June 2020

Electron microscopic examination of ultra-thin sections of dilute suspensions of biologic material is difficult, time consuming and unrewarding. Generally, a cell mass from larger cultures compacted in some way or tissue pieces are handled successfully. We have developed a rapid method for embedding and sectioning more dilute particulate materials, such as membrane components harvested from sucrose gradients or dilute cultures.Bacterial cells, Bacillus cereus and Bacillus subtilis were cultured using a standard growth medium (Tryptone glucose yeast extract broth, 100 ml) for 24 hours at ambient temperature. In this experiment the culture was divided in half at the conclusion of incubation. One half of the mixture (50 ml) was centrifuged to produce a pellet which was immediately frozen in liquid nitrogen. The other half was diluted and utilized during the second part of this experiment.
A Technique for Sequential Examination of in Vitro Macrophage-Tumor Interaction using Lm, Sem and Tem
Authors: Bucana C. , Hobbs B. , Hoyer L. C. , Hanna M. G. 
Published: June 2020

A sequential examination of macrophage-tumor cell interaction in vitro, using time-lapse cinematography followed by SEM and TEM of the same cells, is a valuable asset in the interpretation of in vivo and in vitro cell-mediated cytotoxicity assays that are widely used in tumor immunology. Previous reports on sequential examination of biological specimens involved large tissue blocks. This report describes a technique that allows sequential examination of cell - cell interaction using three modes of microscopy.Guinea pig hepatoma (L-10) cells were plated sparsely on 25mm glass coverslips 24hr before adding guinea pig peritoneal exudate cells (PEC). PEC were allowed to settle for 1 l/2hr; the coverslips were then transferred to a Dvorak-Stotler chamber and examined with a Zeiss photomicroscope III.
Recent Applications in Combined Transmission Electron Microscopy and Microanalysis
Authors: Chescoe Miss D. , Beeston B.E.P. 
Published: June 2020

An AEI CORA has recently been used to examine a wide number of applications mainly in the biological field. This instrument with its unique double field condenser/objective lens combines the normal accepted high resolution performance of a transmission electron microscope with X-ray analysis of areas down to a 250°A in diameter.Environmental pollution is one field in which this technique excels. Although the dangers of handling asbestos are well known and stringent controls operate in industrial use, an individual can be at risk in domestic use, especially when handling some of the home repair kits. Certain spackling compounds were examined by dispersing a small quantity in distilled water and drying down onto a carbon coated grid. As can be seen from the micrograph Fig la many fibres exist, similar in appearance to asbestos.
In Situ SEM Observations of Sintering of Gold Compacts
Authors: Levin E. R. , Auth G. R. , Bube K. R. 
Published: June 2020

As part of a study of metallization of preglazed ceramic surfaces for hybrid microcircuits, direct observations of the sintering of gold powders at temperatures in the 800-900°C range have been made in the scanning electron microscope. The changes occurring in the layers at the high temperatures were followed in detail at high magnification. Video tape recordings were made showing the sintering of the gold and the accompanying flow of the glass bonding medium.The specimens were specially prepared for the SEM studies on thin rectangular ceramic substrates 0.13mmx2mmx8mm. The unsintered gold powder, dispersed in an organic vehicle, was screen-printed in 1 mm-wide stripes along the length of substrate. Prior to sintering, the organic binder was removed by prefiring in air, typically at 400 °C for two minutes (Fig. 1). An intermediate layer of lead-borosilicate glass was used between the substrate and the metal compact to promote adhesion on sintering.
Preparation of Scanning Electron Microscope Specimens from Liquid Dispersions of Solid Particulates
Authors: Walter Earl R. 
Published: June 2020

A variety of techniques have been developed which do not materially alter the state of flocculation of solid particles dispersed in a liquid when that dispersion is prepared for transmission electron microscopy. However, similar techniques have not been developed to minimize the effect of surface tension on the flocculation of particles when dispersions are dried down on a support for scanning electron microscopy. The problem is often compounded by the larger sample size involved and the generally larger particles studied in the SEM. With today's emphasis on air and water polution, sewage treatment, etc., simple, rapid techniques of sample preparation to allow reliable particle size studies are becoming increasingly important.When a liquid dispersion of solid particles is dried down on a substrate for SEM characterization, surface tension and thermal gradients in the evaporating liquid may materially alter the degree of flocculation and introduce severe particle size fractionation in different areas of the specimen.
Scanning Auger Electron Microscopy at 30 Nm Resolution
Authors: Venables J. A. , Janssen A. P. , Harland C. J. , Joyce B. A. 
Published: June 2020

An HB50 FEG SEM with a specially designed conical final lens and UHV specimen chamber has been supplied by V.G. Microscopes Ltd., East Grinstead, U.K., to which we have fitted a CMA supplied by Varian Associates, Inc. The design of this microscope has been outlined elsewhere (1) but the geometry can be understood by reference to fig. 1. The CMA is bellows mounted so that it can be aligned with respect to the SEM beam, and retracted in other modes of operation. Auger signal detection is via a Brookdeal 9501 phase sensitive detector (PSD) system.An input module for the SEM has been constructed to feed the PSD signal into the SEM display system, resulting in the following modes of Auger operation: (1) An energy scan uses the ‘spectrum’ mode of the microscope to drive the energy ramp of the CMA, resulting in a (dN/dE) Auger spectrum from a chosen point on the sample scanned between any two energy limits; (2) A line scan uses the ‘line’ mode of the microscope to display the Auger signal dN/dE for a given element (i.e. at a given E) from a chosen line on the sample.