Laser Surface Engineering for Improved Biocompatibility of Orthopedic Biomaterials

Laser Surface Engineering for Improved Biocompatibility of Orthopedic Biomaterials

Date: April 19, 2012
Creator: Dahotre, Sanket; Paital, Sameer & Banerjee, Rajarshi
Description: Poster presentation for the 2012 University Scholars Day at the University of North Texas discussing research on laser surface engineering for improved biocompatibility of orthopedic biomaterials.
Contributing Partner: UNT Honors College
Structural investigation of B{sup +} ion implantation induced amorphization in polycrystalline Ni thin films

Structural investigation of B{sup +} ion implantation induced amorphization in polycrystalline Ni thin films

Date: June 1, 1996
Creator: Liu, P.C.; Zaluzec, N.J.; Okamoto, P.R. & Meshii, M.
Description: High fluence metalloid ion implantation have been shown to induce amorphous phase formation in transition metals systems. In this study, electron energy loss spectroscopy and energy filtered selective area electron diffraction have been used along with conventional TEM to characterize the structural and electronic changes resulting from B{sup +} ion implantation into polycrystalline Ni thin films.
Contributing Partner: UNT Libraries Government Documents Department
Crystal and magnetic structure of stoichiometric YFe{sub 2}O{sub 4}

Crystal and magnetic structure of stoichiometric YFe{sub 2}O{sub 4}

Date: August 1, 1994
Creator: Katano, S.; Funahashi, S.; Matsumoto, T.; Iida, J.; Tanaka, M. & Cable, J.W.
Description: Crystal structure of stoichiometric YFe{sub 2}O{sub 4} powder was studied by high-resolution neutron diffraction at room temperature, 225 K and 80 K. Rietveld refinements of the diffraction patterns give reasonable fits with space group R{bar 3}m (hexagonal) for room temperature, and with P{bar 1} (triclinic) for 225 K. However, the 80 K pattern cannot be fitted at all with the same triclinic symmetry, indicating that the structure is much more complicated. The magnetic reflection has been separated from those complex nuclear peaks by the polarization analysis. The magnetic structure is also fairly complicated both at 225 K and at 80 K.
Contributing Partner: UNT Libraries Government Documents Department
Analytical electron microscopy of rapidly solidified metals

Analytical electron microscopy of rapidly solidified metals

Date: December 31, 1991
Creator: Kelly, T.F.; Holzman, L.M.; Shin, K.; Kim, Y.W.; Bae, J.C.; Flinn, J.E. et al.
Description: Examples of the need to characterize rapidly solidified metals on submicron scale are given for centrifugally atomized steel powder and electrohydrodynamically atomized submicron spheres. Materials studied include Fe-40wt% Ni, 304 SS, Fe-20at.%Co, and pure V.
Contributing Partner: UNT Libraries Government Documents Department
Continued study of the effects of heat treatment and microstructure on electrocatalyst performance. Final report, July 29, 1991--December 20, 1991

Continued study of the effects of heat treatment and microstructure on electrocatalyst performance. Final report, July 29, 1991--December 20, 1991

Date: February 1, 1992
Creator: Stoner, G.E.
Description: Platinum and platinum-chromium bulk electrodes were analyzed in 100 wt.% H{sub 3}PO{sub 4} at 200{degrees} C to evaluate the kinetics for the oxygen reduction reaction (ORR) in the phosphoric acid fuel cell (PAFC) operating environment. Dispersed platinum and platinum-chromium catalyst electrodes were operated potentiostatically under simulated PAFC operating conditions (0.7 V vs. RHE in 100 wt.% H{sub 3}PO{sub 4} at 200{degrees} C) using the submerged mode to evaluate the degradation mechanism. Differences observed between the hanging meniscus rotating disk (HMRD) electrode and the rotating disk electrode (RDE) method were related to the different hydrodynamics present in the hanging meniscus. The boundary conditions applicable to an infinite rotating disk are no longer present. The most probable cause for the observed differences is that the surface of the HMRD electrode is no longer uniformly accessible with respect to the diffusing species. Therefore, the kinetic data extracted from the mixed control conditions are altered sufficiently so that precise potential-current curves cannot be obtained. However, the data obtained are highly reproducible. Therefore, the method appears suitable for determining comparative kinetic data for platinum and platinum-chromium at 200 a C in 100 wt.% H{sub 3}PO{sub 4}, where RDE designs will not function. Cyclic voltammetry conducted ...
Contributing Partner: UNT Libraries Government Documents Department
Why in situ, real-time characterization of thin film growth processes?

Why in situ, real-time characterization of thin film growth processes?

Date: August 1, 1995
Creator: Auciello, O. & Krauss, A.R.
Description: Since thin-film growth occurs at the surface, the analytical methods should be highly surface-specific. although subsurface diffusion and chemical processes also affect film properties. Sampling depth and ambient-gas is compatibility are key factors which must be considered when choosing in situ probes of thin-film growth phenomena. In most cases, the sampling depth depends on the mean range of the exit species (ion, photon, or electron) in the sample. The techniques that are discussed in this issue of the MRS Bulletin (1) have been chosen because they may be used for in situ, real-time analysis of film-growth phenomena in vacuum and in the presence of ambient gases resulting either from the deposition process or as a requirement for the production of the desired chemical phase. A second criterion for inclusion is that the instrumentation be sufficiently compact and inexpensive to permit use as a dedicated tool in a thin-film deposition system.
Contributing Partner: UNT Libraries Government Documents Department
Materials sciences programs: Fiscal year 1995

Materials sciences programs: Fiscal year 1995

Date: May 1, 1996
Creator: unknown
Description: The purpose of this report is to provide a convenient compilation and index of the DOE Materials Science Division programs. This compilation is primarily intended for use by administrators, managers, and scientists to help coordinate research. The report is divided into eight sections. Section A contains all Laboratory projects, Section B has all contract research projects, Section C has projects funded under the Small Business Innovation Research Program, Section D describes the Center of Excellence for the Synthesis and Processing of Advanced Materials and E has information on major user facilities. F describes other user facilities, G as a summary of funding levels and H has indices characterizing research projects.
Contributing Partner: UNT Libraries Government Documents Department
Sputtering induced changes in defect morphology and dopant diffusion for Si implanted GaAs: Influence of ion energy and implant temperature

Sputtering induced changes in defect morphology and dopant diffusion for Si implanted GaAs: Influence of ion energy and implant temperature

Date: December 1, 1994
Creator: Robinson, H.G.; Deal, M.D.; Lee, C.C.; Haynes, T.E.; Allen, E.L. & Jones, K.S.
Description: Experimental observations of dopant diffusion and defect formation are reported vs ion energy and implant temperature in Si-implanted GaAs. In higher energy implants (>100 keV), little or no diffusion occurs, while at energies less than 100 keV, the amount of dopant redistribution is inversely proportional to energy. Extended defect density shows the opposite trend, increasing with ion energy. Similarly, Si diffusion during post implant annealing decreases by a factor of 2.5 as the implant temperature increases from -2 to 40 C. In this same temperature range, maximum depth and density of extrinsic dislocation loops increases by factors of 3 and 4, respectively. Rutherford backscattering channeling indicates that Si- implanted GaAs undergoes an amorphous-to-crystalline transition at Si implant temperatures between -51 and 40 C. A unified explanation of the effects of ion energy and implant temperature on both diffusion and dislocation formation is proposed based on known differences in sputter yields between low and high energy ions and crystalline and amorphous semiconductors. The model assumes that the sputter yield is enhanced at low implant energies and by amorphization, thus increasing the excess vacancy concentration. Estimates of excess vacancy concentration are obtained by simulations of the diffusion profiles and are quantitatively consistent ...
Contributing Partner: UNT Libraries Government Documents Department
High Temperature Alkali Corrosion of Dense SN4 Coated with CMZP and Mg-Doped A21TiO5 in Coal Gas

High Temperature Alkali Corrosion of Dense SN4 Coated with CMZP and Mg-Doped A21TiO5 in Coal Gas

Date: March 1, 1998
Creator: Brown, J. J. & Thierry, Nguyen
Description: Over the past twenty years silicon based ceramics have generated considerable enthusiasm in the scientific community. Of particular interest is Si3N4, one of the leading candidates of this family, for very demanding structural applications. Its properties are well known and include a high strength to weight ratio, a high chemical resistance, and excellent high temperature properties. However, it was reported in previous papers that the performances of Si3N4 were dramatically affected by hot alkali molten salts. In order to alleviate this phenomenon, it was suggested that certain oxide ceramics, which exhibit better resistance to the alkali corrosion, could be applied as protective coatings. Using the sol-gel process and dip coating technique, CMZP and Mg-doped Al2TiO5 thin films were deposited on Si3N4 substrates and exposure to a sodium containing atmosphere was carried out. During this reporting period, the emphasis was placed on investigating the microstrutural changes of coated and uncoated samples as well as on assessing their alkali corrosion resistance.
Contributing Partner: UNT Libraries Government Documents Department
A mass spectrometric analysis of {gamma}-GPS films

A mass spectrometric analysis of {gamma}-GPS films

Date: June 1, 1996
Creator: Dillingham, R.G.; Boerio, F.J.; Bertelsen, C.; Savina, M.R.; Lykke, K.R. & Calaway, W.F.
Description: {gamma}-glycidoxypropyltrimethoxysilane ({gamma}-GPS) is used for pre-treatment of grit-blasted aluminum before adhesive bonding. This paper discusses analysis of non-reflective grit-blasted surfaces using mass spectrometry of species that were either sputtered off using an ion beam or thermally desorbed as neutrals using a pulsed laser and then post-ionized using a secondary laser. Results show that fragmentation is excessive and structural information is difficult to obtain from the spectra.
Contributing Partner: UNT Libraries Government Documents Department
FIRST PREV 1 2 3 4 5 NEXT LAST