A5067019633- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Particle Accelerators and Free-Electron Lasers
- Metal and Thin Film Mechanics
- Catalytic Processes in Materials Science
- Gyrotron and Vacuum Electronics Research
- Advanced Surface Polishing Techniques
- Physics of Superconductivity and Magnetism
- Advanced Materials Characterization Techniques
- Magnetic confinement fusion research
- Laser Design and Applications
- Electron and X-Ray Spectroscopy Techniques
- Laser Material Processing Techniques
- Ion-surface interactions and analysis
- Advanced X-ray Imaging Techniques
- Surface Roughness and Optical Measurements
- Molecular Junctions and Nanostructures
- Fusion materials and technologies
- Mass Spectrometry Techniques and Applications
- nanoparticles nucleation surface interactions
- Inorganic Chemistry and Materials
- Diamond and Carbon-based Materials Research
- Asymmetric Hydrogenation and Catalysis
- Laser-induced spectroscopy and plasma
University of South Carolina
2025
Virginia Tech
2011-2024
Thomas Jefferson National Accelerator Facility
2015-2024
North Carolina State University
2018-2022
William & Mary
2011-2020
Williams (United States)
2011-2020
Dana-Farber Cancer Institute
2018
Old Dominion University
2011-2015
Langley Research Center
2015
Texas A&M University
2015
Composition measurements of Cu–Ni and Au–Pd alloy surfaces annealed at 600 °C under steady-state bombardment conditions are reported. A unique procedure for studying the effects enhanced diffusion is employed. The ion-bombardment-induced alteration composition near surface region a Cu–Ni, Ag–Au, has been studied between 200 ° 550 °C. results have extrapolated to lower temperatures used explain conflicting reports differential sputtering in these alloys.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanisms of chromium(III) sorption on silica. 1. Chromium(III) surface structure derived by extended x-ray absorption fine spectroscopyScott E. Fendorf, Gerry M. Lamble, Michael G. Stapleton, J. Kelley, and Donald L. SparksCite this: Environ. Sci. Technol. 1994, 28, 2, 284–289Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published inissue 1 February...
Recently, Nb superconducting radio frequency cavities vacuum heat treated between 300 and 400 °C for a few hours have exhibited very high quality factors (∼5 × 1010 at 2.0 K). Secondary ion mass spectrometry measurements of O, N, C show that this enhancement in RF surface conductivity is primarily associated with interstitial O alloying via dissolution diffusion the native oxide. We use theory oxide decomposition to quantify previously unknown parameters crucial modeling process....
We generalize a native Nb2O5 dissolution model [G. Ciovati, Appl. Phys. Lett. 89, 022507 (2006)] to sequential overlayer dissolutions, multilayer dissolution, and realistic temperature profiles, which may be applicable other materials. The is applied secondary ion mass spectrometry depth profile measurements for varying profiles two-step oxide in Nb found agree well. In the context of Meissner screening response due impurity on length scale London penetration depth, shallow diffusion O...
Niobium surfaces are commonly electropolished in an effort to obtain optimal smoothness for high-field superconducting radio-frequency cavity applications. We report the use of controlled electrochemical analysis techniques characterize electropolishing Nb a sulfuric and hydrofluoric acid electrolyte. Through reference electrode, we able clearly distinguish anode cathode polarization potentials as well electrolyte voltage drop, which together sum applied power supply voltage. then identify...
Abstract Determining the local chemical environment of a species is often necessity for evaluating its reactivity in environment. However, obtaining direct molecular‐level information problematic and may only be possible with severely invasive techniques. We discuss physical aspects x‐ray absorption fine structure spectroscopy (XAFS) application soils. This technique can determine structural surroundings particular elemental soil water or other natural systems, without need to subject sample...
Several models have been proposed to predict the direction and extent of surface segregation in binary metal alloys. Auger electron spectroscopy (AES) has proven useful study these systems qualitatively, but results AES difficult quantify. Ion scattering (ISS) offers an alternative having true first-monolayer sensitivity. ISS was used Ag–Au Pt–Cu systems. Results are compared with previous findings model predictions.
The catalytic activity of silver catalysts in the ethylene epoxidation reaction are intrinsically linked to their faceting. Here, nanowires, representing Ag(100), and spherical catalysts, embodying Ag(111), were synthesized using modified polyol wet impregnation methods, respectively. Recognizing size-dependent nature catalysis, two distinct sizes particles serve as comparative benchmarks for nanowire activity. Silver promoted with optimal cesium loading. Furthermore, nanowires underwent...
The antibacterial effectiveness of an ultraviolet-irradiated nylon 6, 6 film was investigated for potential use as a food-packaging material to reduce the surface microbial contamination foods. film-surface analyses showed that UV irradiation induced conversion amide groups amines. Irradiation also increased dimensional scale topography (depth valleys) approximately 5-fold on nanometers. irradiated demonstrated antagonistic activity against Staphylococcus aureus 25923 and Escherichia coli...
A model catalyst prepared from [Re2Pt(CO)12] supported on γ-Al2O3 was characterized by extended X-ray absorption fine structure (EXAFS) spectroscopy, and its stability in operation a flow reactor tested for the dehydrogenation of methylcyclohexane at 1 atm 400 °C. EXAFS data characterizing unused measured both Re LIII Pt edges liquid nitrogen temperature with sample presence H2 distinguish Re−Pt Pt−Pt Re−Re interactions. The results form basis simplified bimetallic structures, consisting...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface-mediated organometallic synthesis: preparation of osmium carbonyl clusters [Os5C(CO)14]2- and [Os10C(CO)24]2- on the basic magnesium oxide surfaceH. Henry Lamb, Anthony S. Fung, Patricia A. Tooley, Jose Puga, Theodore R. Krause, Michael J. Kelley, Bruce C. GatesCite this: Am. Chem. Soc. 1989, 111, 22, 8367–8373Publication Date (Print):October 1, 1989Publication History Published online1 May 2002Published inissue 1 October...
This review paper describes the energy-upgraded Continuous Electron Beam Accelerator Facility (CEBAF) accelerator. superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing 88 cavities that have operated cw at an average accelerating gradient of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>20</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>MV</a:mi><a:mo>/</a:mo><a:mi...
Surface topography characterization is a continuing issue for the superconducting radio frequency (SRF) particle accelerator community. Efforts are under way to both improve surface and its analysis using various techniques. In measurement of topography, power spectral density (PSD) promising method quantify typical parameters develop scale-specific interpretations. PSD can also be used indicate how process modifies at different scales. However, generating an accurate meaningful topographic...
Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). resulting topography characterized by atomic force microscopy (AFM). power spectral density (PSD) AFM data provides more thorough description the than single-value roughness measurement. In this work, one dimensional average PSD functions derived from BCP EP...
By making a relativistic electron beam wiggle its way through an array of magnets, one can generate intense coherent light with wavelengths tunable from centimeters to angstroms.