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in subjects: "Microscopy"

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Heavy-Ion Irradiation of Thulium(III) Oxide Targets Prepared by Polymer-Assisted Deposition

Thulium(III) oxide (Tm{sub 2}O{sub 3}) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method's feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 {micro}g/cm{sup 2}) and were irradiated with an {sup 40}Ar beam at laboratory frame energy of {approx}210 MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1 nm for a {approx}250 n… more

Date: September 15, 2008

Creator: Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, Tashi; Ashby, Paul D.; Gates, Jacklyn M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Silver and Gold Based Autometallography of Nanogold.

For many applications, silver salt-based autometallography (often also called silver enhancement or silver development) is required to visualize colloidal gold (1-5 nm in diameter) or the small 1.4 nm Nanogold{reg_sign} particles (Nanoprobes, Yaphank, NY, USA). Although even Nanogold may be seen directly by scanning-transmission electron microscopy (STEM), by transmission EM (TEM; in thin sections without stain or ice-embedded cryo-EM samples), energy filtered TEM, and scanning EM (SEM), silver… more

Date: April 17, 2002

Creator: Hainfeld, J. F. & Powell, R. D.

Item Type: Book

Partner: UNT Libraries Government Documents Department

open access

Atomic scale investigations of the thermal and electron induced chemistry of small molecules on platinum(111) as revealed by scanning tunneling microscopy

The work presented here can be divided into two parts: 1) an experimental and analysis section dealing with the investigation of small molecules such as methyl bromide, carbon dioxide, diatomic nitrogen, methane and methane?s photochemical derivative methyl radical adsorbed onto the Pt(111) surface, and 2) A detailed explanation of the current STM and chamber, with included designs and detailed instructions for operation and maintenance of both the STM and chamber. The investigations of the met… more

Date: January 1, 2006

Creator: Schwendemann, Todd Charles

Item Type: Text

Partner: UNT Libraries Government Documents Department

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Analytical Chemistry Division Semiannual Progress Report for Period Ending April 20, 1954

Progress report of the Oak Ridge National Laboratory Analytical Chemistry Division providing updates on various projects, experiments, and other work in ionic analyses, analytical instrumentation, radiochemical analyses, activation analyses, spectrochemical analyses, inorganic preparations, optical and electron microscopy.

Date: July 5, 1956

Creator: Kelley, M. T.; Susano, C. D. & Raaen, H. P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Modeling AFM Induced Mechanical Deformation of Living Cells

Finite element modeling has been applied to study deformation of living cells in Atomic Force Microscopy (AFM) and particularly Recognition Force Microscopy (RFM). The abstract mechanical problem of interest is the response to RFM point loads of an incompressible medium enclosed in a fluid membrane. Cells are soft systems, susceptible to large deformations in the course of an RFM measurement. Often the local properties such as receptor anchoring forces, the reason for the measurement, are obscu… more

Date: November 15, 2002

Creator: Rudd, Robert E.; McElfresh, Michael; Balhorn, Rod; Allen, Michael J. & Belak, James

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Atomic structures of inversion domain boundaries and dislocations in sintered AlN

AlN is an attractive material because of its mechanical, thermal and electronic properties. However, these properties are often adversely altered by extended defects such as inversion domain boundaries (IDBs), and through impurities associated with the defects, especially oxygen. Thus to improve the properties of the material it is important to understand the structures of the defects. A number of studies have been carried out to characterize these defects using fringe contrast, weak-beam, conv… more

Date: February 1, 1998

Creator: Yan, Y.; Chisholm, M.F. & Pennycook, S.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

MATERIALS WITH COMPLEX ELECTRONIC/ATOMIC STRUCTURES

We explored both experimentally and theoretically the behavior of materials at stresses close to their theoretical strength. This involves the preparation of ultra fine scale structures by a variety of fabrication methods. In the past year work has concentrated on wire drawing of in situ composites such as Cu-Ag and Cu-Nb. Materials were also fabricated by melting alloys in glass and drawing them into filaments at high temperatures by a method known as Taylor wire technique. Cu-Ag microwires ha… more

Date: September 1, 2000

Creator: PARKIN, D. M.; CHEN, L. & AL, ET

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Nanostructured Arrays Formed by Finely Focused Ion Beams

Amorphous, polycrystalline, and single crystal nanometer dimension particles can be formed in a variety of substrates by ion implantation and subsequent annealing. Such composite colloidal materials exhibit unique optical properties that could be useful in optical devices, switches, and waveguides. However colloids formed by blanket implantation are not uniform in size due to the nonuniform density of the implant, resulting in diminution of the size dependent optical properties. The object of t… more

Date: November 30, 1998

Creator: Budai, J. D.; Datsos, P. G.; Feldman, L. C.; Heinig, K. H.; Meldrum, A.; Strobel, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

(Energy related studies utilizing microline thermochronology)

In our first year of the current funding cycle, we have investigated three interrelated aspects of K-feldspar thermochronology; (1) the Ar diffusion properties and microstructures of K-feldspars, (2) the thermal evolution of the Valles Caldera and (3) the continued development of microanalysis. Results of TEM and light microscopy on heated and unheated samples of MH-10 K-feldspar reveal three classes of substructure are present: (1) cross hatched extinction is common and there is almost no albi… more

Date: January 1, 1991

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Research on hydrogen effects on phase distribution ahead of propagating cracks in stainless steel. Final report

This research was performed in support of computations to determine the distribution of hydrogen at a crack tip in an unstable stainless steel. It involved metallographic observations of the distribution of martensite at a stressed crack tip. It is concluded that the martensite phase distribution is much too fine to model realistically by the finite element method when far-field stress effects must be included. The mesh size would have to be less than 50 micrometers in order to include the effe… more

Date: December 31, 1993

Creator: Altstetter, C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Macroscopic Superlattices of CdSe Colloidal Nanocrystals: Appearance and Optical Properties

Two and three dimensional assemblies of colloidal nanocrystals (NCs) have been of great interest during recent years [1-3]. While size-dependent optical and electronic properties of isolated particles are particularly important for fundamental research, studies of their ordered assemblies provide a transition path to the engineering of materials and devices for future practical applications. Assemblies of NCs of different materials, such as semiconductors, metals and metal oxides, have been rep… more

Date: March 25, 2004

Creator: Zaitseva, N; Manna, L; Leon, F; Gerion, D; Saw, C & Galli, G

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Advanced Transmission Electron Microscopy of Pu Alloys

The characterization of microstructural changes in Pu-Ga alloys resulting from storage and aging phenomena is an important technical challenge to the nuclear Stockpile Stewardship program. We have identified at least two age-related phenomena that may occur in Pu alloys, dimensional changes due to the initial transient, helium accumulation, and void swelling, and phase instability. The initial transient is a well-known effect that results from the initial cascade damage. This form of dimensiona… more

Date: January 27, 2003

Creator: Schwartz, A J; Wall, M A; Wolfer, W G & Moore, K T

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Microanalysis at the atomic level

The optical arrangement of the high-resolution scanning transmission electron microscope (STEM) allows incoherent imaging conditions to be established simultaneously for both elastically and inelastically scattered electrons, with good detection efficiencies. For zone axis illumination and localized inelastic transitions, both images show a resolution governed by the incident probe intensity profile, with maximum intensity occurring when the probe is located over the atomic columns. The high in… more

Date: August 1, 1995

Creator: Pennycook, S. J.; Jesson, D. E.; Nellist, P. D.; McGibbon, M. M.; McGibbon, A. J. & Browning, N. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Report to the DOE on the “Crud II” project

This report documents SEM, TEM, and chemical analyses from crud samples from a commercially operating reactor.

Date: September 1, 2006

Creator: Janney, Dawn Elizabeth; Porter, Douglas L.; Earle, O. Keener; Peterson, Joshua L.; Demmer, Rick; Giglio, Jeffrey J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Growth and Characterization of GaN As(P) for High Efficiency Solar Cells: Final Subcontract Report, 29 July 1999--28 September 2003

This report describes the characterization of GaAs1-xNx and GaP1-xNx alloys using scanning tunneling microscopy (STM) and ballistic electron emission microscopy (BEEM). One objective was to understand the origins of the giant bandgap bowing of these compound semiconductor alloys as a function of nitrogen concentration. The STM and BEEM have been used to characterize GaNxAs1-x and GaNxP1-x as a function of composition. The reduction in bandgap has been measured. Detailed studies of the band stru… more

Date: June 1, 2004

Creator: Narayanamurti, V.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Structure of oxygen-implanted (111) silicon before and after heat-pulse annealing

The structure of oxygen-implanted silicon (dose -7.3 x 10/sup 16/cm/sup -2/) has been studied by transmission electron microscopy (TEM). The as-implanted material exhibited four structurally different layers: defect-free monocrystalline silicon, amorphous silicon, monocrystalline silicon with a high defect density, and the perfect crystalline substrate. After heat-pulse annealing for 20 s at 800/sup 0/C, 900/sup 0/C, or 1000/sup 0/C, the amorphous layer recrystallized resulting in polycrystalli… more

Date: October 1, 1985

Creator: Liliental-Weber, Z.; Carpenter, R.W. & Kelly, J.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Probe and object function reconstruction in incoherent stem imaging

Using the phase-object approximation it is shown how an annular dark- field (ADF) detector in a scanning transmission electron microscope (STEM) leads to an image which can be described by an incoherent model. The point spread function is found to be simply the illuminating probe intensity. An important consequence of this is that there is no phase problem in the imaging process, which allows various image processing methods to be applied directly to the image intensity data. Using an image of … more

Date: September 1, 1996

Creator: Nellist, P.D. & Pennycook, S.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Residual stress measurement and microstructural characterization of thick beryllium films

Beryllium films are synthesized by a magnetron sputtering technique incorporating in-situ residual stress measurement. Monitoring the stress evolution in real time provides quantitative through-thickness information on the effects of various processing parameters, including sputtering gas pressure and substrate biasing. Specimens produced over a wide range of stress states are characterized via transmission and scanning electron microscopy, and atomic force microscopy, in order to correlate the… more

Date: February 11, 2008

Creator: Detor, A.; Wang, M.; Hodge, A. M.; Chason, E.; Walton, C.; Hamza, A. V. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Coal liquefaction process streams characterization and evaluation: Electron microscopy observations of resids obtained from coal liquefaction experiments

The study demonstrated the feasibility of using scanning transmission electron microscopy (STEM) spectroscopy accompanied by energy dispersive X-ray (EDX) spectroscopy for the examination of the (THF)-insoluble portion of distillation resid materials derived from direct coal liquefaction. The technique was able to determine the distribution, morphology and elemental composition of dispersed catalyst components in the insoluble portion of the distillation resids. An attempt was made to use trans… more

Date: November 1, 1992

Creator: Vander Sande, J. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City

This study reports on heterogeneous ice nucleation activity of predominantly organic (or coated with organic material) anthropogenic particles sampled within and around the polluted environment of Mexico City. The onset of heterogeneous ice nucleation was observed as a function of particle temperature (Tp), relative humidity (RH), nucleation mode, and particle chemical composition which is influenced by photochemical atmospheric aging. Particle analyses included computer controlled scanning ele… more

Date: June 20, 2010

Creator: Knopf, D. A.; Wang, B.; Laskin, A.; Moffet, R. C. & Gilles, M. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electrical transport and mechanical properties of alkylsilane self-assembled monolayers on silicon surfaces probed by atomic force microscopy

The correlation between molecular conductivity and mechanical properties (molecular deformation and frictional responses) of hexadecylsilane self-assembled monolayers was studied with conductive probe atomic force microscopy/friction force microscopy in ultrahigh vacuum. Current and friction were measured as a function of applied pressure, simultaneously, while imaging the topography of self-assembled monolayer molecule islands and silicon surfaces covered with a thin oxide layer. Friction imag… more

Date: February 6, 2009

Creator: Park, Jeong Young; Qi, Yabing; Ashby, Paul D.; Hendriksen, Bas L.M. & Salmeron, Miquel

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Enhancement of the vibration stability of a microdiffraction goniometer.

High-precision instrumentation, such as that for x-ray diffraction, electron microscopy, scanning probe microscopy, and other optical micropositioning systems, requires the stability that comes from vibration-isolated support structures. Structure-born vibrations impede the acquisition of accurate experimental data through such high-precision instruments. At the Advanced Photon Source, a multiaxis goniometer is installed in the 2-ID-D station for synchrotron microdiffraction investigations. How… more

Date: July 2, 2002

Creator: Lee, S. H.; Preissner, C.; Lai, B.; Cai, Z. & Shu, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Defect reduction in (112_O) a-plane GaN by two-stage epitaxiallateral overgrowth

In the epitaxial lateral overgrowth (ELO) of (11{bar 2}0) a-plane GaN, the uneven growth rates of two opposing wings, Ga- and N-wings, makes the coalescence of two neighboring wings more difficult than that in c-plane GaN. We report a two-stage growth method to get uniformly coalesced epitaxial lateral overgrown a-plane GaN using metalorganic chemical vapor deposition (MOCVD) by employing relatively lower growth temperature in the first step followed by enhanced lateral growth in the second. Us… more

Date: October 20, 2006

Creator: Ni, X.; Ozgur, U.; Fu, Y.; Biyikli, N.; Xie, J.; Baski, A.A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Interfacial segregation, pore formation and scale adhesion on NiAlalloys

Alloys of commercial grades that do not contain a reactive element, such as yttrium, often develop pores at the scale/alloy interface. The accumulation and growth of these pores greatly weaken scale adhesion. The purpose of this study is to evaluate pore development in Fe-40at%Al and determine the change in pore volume with oxidation time. Experimental results are then compared to a theoretical calculation where all vacancies are allowed to condense as voids. After removing the oxide scales tha… more

Date: October 9, 2001

Creator: Hou, Peggy Y. & Priimak, K.

Item Type: Article

Partner: UNT Libraries Government Documents Department