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3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor (open access)

3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor

The DOE Advanced Fuel Cycle Initiative and Generation IV reactor programs are developing new fuel types for use in the current Light Water Reactors and future advanced reactor concepts. The Advanced Gas Reactor program is planning to test fuel to be used in the Next Generation Nuclear Plant (NGNP) nuclear reactor. Preliminary information for assessing performance of the fuel will be obtained from irradiations performed in the Advanced Test Reactor large ''B'' experimental facility. A test configuration has been identified for demonstrating fuel types typical of gas cooled reactors or fast reactors that may play a role in closing the fuel cycle or increasing efficiency via high temperature operation Plans are to have 6 capsules, each containing 12 compacts, for the test configuration. Each capsule will have its own temperature control system. Passing a helium-neon gas through the void regions between the fuel compacts and the graphite carrier and between the graphite carrier and the capsule wall will control temperature. This design with three compacts per axial level was evaluated for thermal performance to ascertain the temperature distributions in the capsule and test specimens with heating rates that encompass the range of initial heat generation rates.
Date: October 6, 2004
Creator: Ambrosek, Richard G.; Chang, Gray S. & Utterbeck, Debby J.
System: The UNT Digital Library
3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor (open access)

3-D Thermal Evaluations for a Fueled Experiment in the Advanced Test Reactor

The DOE Advanced Fuel Cycle Initiative and Generation IV reactor programs are developing new fuel types for use in the current Light Water Reactors and future advanced reactor concepts. The Advanced Gas Reactor program is planning to test fuel to be used in the Next Generation Nuclear Plant (NGNP) nuclear reactor. Preliminary information for assessing performance of the fuel will be obtained from irradiations performed in the Advanced Test Reactor large “B” experimental facility. A test configurations has been identified for demonstrating fuel types typical of gas cooled reactors or fast reactors that may play a role in closing the fuel cycle or increasing efficiency via high temperature operation Plans are to have 6 capsules, each containing 12 compacts, for the test configuration. Each capsule will have its own temperature control system. Passing a helium-neon gas through the void regions between the fuel compacts and the graphite carrier and between the graphite carrier and the capsule wall will control temperature. This design with three compacts per axial level was evaluated for thermal performance to ascertain the temperature distributions in the capsule and test specimens with heating rates that encompass the range of initial heat generation rates.
Date: October 1, 2004
Creator: Ambrosek, Richard; Chang, Gray & Utterbeck, Debra
System: The UNT Digital Library
14th Workshop on Crystalline Silicon Solar Cells& Modules: Materials and Processes; Summary of Discussion Sessions (open access)

14th Workshop on Crystalline Silicon Solar Cells& Modules: Materials and Processes; Summary of Discussion Sessions

The 14th Workshop discussion sessions addressed funding needs for Si research and for R&D to enhance U.S. PV manufacturing. The wrap-up session specifically addressed topics for the new university silicon program. The theme of the workshop, Crystalline Silicon Solar Cells: Leapfrogging the Barriers, was selected to reflect the astounding progress in Si PV technology during last three decades, despite a host of barriers and bottlenecks. A combination of oral, poster, and discussion sessions addressed recent advances in crystal growth technology, new cell structures and doping methods, silicon feedstock issues, hydrogen passivation and fire through metallization, and module issues/reliability. The following oral/discussion sessions were conducted: (1) Technology Update; (2) Defects and Impurities in Si/Discussion; (3) Rump Session; (4) Module Issues and Reliability/Discussion; (5) Silicon Feedstock/Discussion; (6) Novel Doping, Cells, and Hetero-Structure Designs/Discussion; (7) Metallization/Silicon Nitride Processing/Discussion; (8) Hydrogen Passivation/Discussion; (9) Characterization/Discussion; and (10) Wrap-Up. This year's workshop lasted three and a half days and, for the first time, included a session on Si modules. A rump session was held on the evening of August 8, which addressed efficiency expectations and challenges of c Si solar cells/modules. Richard King of DOE and Daren Dance of Wright Williams& Kelly (formerly of Sematech) spoke …
Date: October 1, 2004
Creator: Sopori, B.; Tan, T.; Sinton, R. & Swanson, D.
System: The UNT Digital Library
2004 Atomic and Molecular Interactions Gordon Research Conference (open access)

2004 Atomic and Molecular Interactions Gordon Research Conference

The 2004 Gordon Research Conference on Atomic and Molecular Interactions was held July 11-16 at Colby-Sawyer College, New London, New Hampshire. This latest edition in a long-standing conference series featured invited talks and contributed poster papers on dynamics and intermolecular interactions in a variety of environments, ranging from the gas phase through surfaces and condensed media. A total of 90 conferees participated in the conference.
Date: October 25, 2004
Creator: Dagdigian, Dr. Paul J.
System: The UNT Digital Library
2nd International Conference on Pathways, Networks, and Systems: Theory and Experiments (open access)

2nd International Conference on Pathways, Networks, and Systems: Theory and Experiments

With the availability of whole genome sequences, research attention shifts from gene sequences and genome content to protein functions and systems biology. Genes comprise a major component of the ''parts list'' that is required for building and maintaining of living organisms. Genome DNA sequences reveal the genetic inventory for a rapidly increasing number of species. Defining and interpreting the instruction manual for protein functions, individually and collectively, is the emerging challenge. Defining protein functions is a complex problem because each gene typically encodes several distinct proteins. As a result, the protein inventory includes as many as 100,000 distinct proteins. Protein functions can vary with developmental stage, anatomical location, and environmental context. Like the problem of sequencing the human genome, the multidimensional nature of protein functions in time, space and context constitutes one of the ''big'' problems in biomedical research. Resolving this problem is key to revolutionizing health care where a deep understanding of complex biological systems will lead to more powerful and specific ways to treat, and perhaps, even prevent birth defects and adult diseases. The meeting addressed the above issues.
Date: October 1, 2004
Creator: Aegean Conferences
System: The UNT Digital Library
48Ti(n,xnypz ag) reactions for neutron energies up to 250 MeV (open access)

48Ti(n,xnypz ag) reactions for neutron energies up to 250 MeV

Cross section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy on a {sup 48}Ti sample. Partial {gamma}-ray cross sections for transitions in {sup 45--48}Ti, {sup 44--48}Sc, {sup 42--45}Ca, {sup 41--44}K, and {sup 41--42}Ar have been determined. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the LANSCE/WNR facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed germanium array for neutron induced excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The {gamma}-ray excitation functions were converted to partial {gamma}-ray cross sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). The data will be presented for neutron energies between 1 to 250 MeV. These results are compared with model calculations which include compound nuclear and pre-equilibrium emission.
Date: October 11, 2004
Creator: Dashdorj, D.; Garrett, P. E.; Becker, J. A.; Bernstein, L. A.; Cooper, J. R.; Devlin, M. et al.
System: The UNT Digital Library
Acceleration of Polarized Beams Using Multiple Strong Partial Siberian Snakes (open access)

Acceleration of Polarized Beams Using Multiple Strong Partial Siberian Snakes

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.
Date: October 10, 2004
Creator: Roser, T.; Ahrens, L.; Bai, M.; Courant, E.; Glenn, J. W.; Gupta, R. C. et al.
System: The UNT Digital Library
Acceleressence: Dark energy from a phase transition at the seesawscale (open access)

Acceleressence: Dark energy from a phase transition at the seesawscale

Simple models are constructed for ''acceleressence'' dark energy: the latent heat of a phase transition occurring in a hidden sector governed by the seesaw mass scale v{sup 2}/M{sub Pl}, where v is the electroweak scale and M{sub Pl} the gravitational mass scale. In our models, the seesaw scale is stabilized by supersymmetry, implying that the LHC must discover superpartners with a spectrum that reflects a low scale of fundamental supersymmetry breaking. Newtonian gravity may be modified by effects arising from the exchange of fields in the acceleressence sector whose Compton wavelengths are typically of order the millimeter scale. There are two classes of models. In the first class the universe is presently in a metastable vacuum and will continue to inflate until tunneling processes eventually induce a first order transition. In the simplest such model, the range of the new force is bounded to be larger than 25 {micro}m in the absence of fine-tuning of parameters, and for couplings of order unity it is expected to be {approx} 100 {micro}m. In the second class of models thermal effects maintain the present vacuum energy of the universe, but on further cooling, the universe will ''soon'' smoothly relax to a matter dominated …
Date: October 5, 2004
Creator: Chacko, Z.; Hall, Lawrence J. & Nomura, Yasunori
System: The UNT Digital Library
Activation Energy for Grain Growth in Aluminum Coatings (open access)

Activation Energy for Grain Growth in Aluminum Coatings

To produce a specific grain size in metallic coatings requires precise control of the time at temperature during the deposition process. Aluminum coatings are deposited using electron-beam evaporation onto heated substrate surfaces. The grain size of the coating is determined upon examination of the microstructure in plan view and cross-section. Ideal grain growth is observed over the entire experimental range of temperature examined from 413 to 843 K. A transition in the activation energy for grain growth from 0.7 to 3.8 eV {center_dot} atom{sup -1} is observed as the temperature increases from <526 K to >588 K. The transition is indicative of the dominant mechanism for grain growth shifting with increasing temperature from grain boundary to lattice diffusion.
Date: October 14, 2004
Creator: Jankowski, Alan Frederic; Ferreira, J. L. & Hayes, Jeffrey P.
System: The UNT Digital Library
An adaptive radiation model for the origin of new genefunctions (open access)

An adaptive radiation model for the origin of new genefunctions

The evolution of new gene functions is one of the keys to evolutionary innovation. Most novel functions result from gene duplication followed by divergence. However, the models hitherto proposed to account for this process are not fully satisfactory. The classic model of neofunctionalization holds that the two paralogous gene copies resulting from a duplication are functionally redundant, such that one of them can evolve under no functional constraints and occasionally acquire a new function. This model lacks a convincing mechanism for the new gene copies to increase in frequency in the population and survive the mutational load expected to accumulate under neutrality, before the acquisition of the rare beneficial mutations that would confer new functionality. The subfunctionalization model has been proposed as an alternative way to generate genes with altered functions. This model also assumes that new paralogous gene copies are functionally redundant and therefore neutral, but it predicts that relaxed selection will affect both gene copies such that some of the capabilities of the parent gene will disappear in one of the copies and be retained in the other. Thus, the functions originally present in a single gene will be partitioned between the two descendant copies. However, although this …
Date: October 18, 2004
Creator: Francino, M. Pilar
System: The UNT Digital Library
Adjusted Field Profile for the Chromaticity Cancellation in FFAG Accelerators. (open access)

Adjusted Field Profile for the Chromaticity Cancellation in FFAG Accelerators.

In an earlier report they have reviewed four major rules to design the lattice of Fixed-Field Alternating-Gradient (FFAG) accelerators. One of these rules deals with the search of the Adjusted Field Profile, that is the field non-linear distribution along the length and the width of the accelerator magnets, to compensate for the chromatic behavior, and thus to reduce considerably the variation of betatron tunes during acceleration over a large momentum range. The present report defines the method for the search of the Adjusted Field Profile.
Date: October 13, 2004
Creator: Ruggiero, A. G.
System: The UNT Digital Library
The Advanced High-Temperature Reactor (AHTR) for Producing Hydrogen to Manufacture Liquid Fuels (open access)

The Advanced High-Temperature Reactor (AHTR) for Producing Hydrogen to Manufacture Liquid Fuels

Conventional world oil production is expected to peak within a decade. Shortfalls in production of liquid fuels (gasoline, diesel, and jet fuel) from conventional oil sources are expected to be offset by increased production of fuels from heavy oils and tar sands that are primarily located in the Western Hemisphere (Canada, Venezuela, the United States, and Mexico). Simultaneously, there is a renewed interest in liquid fuels from biomass, such as alcohol; but, biomass production requires fertilizer. Massive quantities of hydrogen (H2) are required (1) to convert heavy oils and tar sands to liquid fuels and (2) to produce fertilizer for production of biomass that can be converted to liquid fuels. If these liquid fuels are to be used while simultaneously minimizing greenhouse emissions, nonfossil methods for the production of H2 are required. Nuclear energy can be used to produce H2. The most efficient methods to produce H2 from nuclear energy involve thermochemical cycles in which high-temperature heat (700 to 850 C) and water are converted to H2 and oxygen. The peak nuclear reactor fuel and coolant temperatures must be significantly higher than the chemical process temperatures to transport heat from the reactor core to an intermediate heat transfer loop and …
Date: October 6, 2004
Creator: Forsberg, C. W.; Peterson, P. F. & Ott, L.
System: The UNT Digital Library
Advanced Nuclear Research Reactor (open access)

Advanced Nuclear Research Reactor

This report describes technical modifications implemented by INVAP to improve the safety of the Research Reactors the company designs and builds.
Date: October 6, 2004
Creator: Lolich, J.V.
System: The UNT Digital Library
Advances in Comprehensive Gyrokinetic Simulations of Transport in Tokamaks (open access)

Advances in Comprehensive Gyrokinetic Simulations of Transport in Tokamaks

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or globally with physical profile variation. Bohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, are illustrated.
Date: October 1, 2004
Creator: Waltz, R. E.; Candy, J.; Hinton, F. L.; Estrada-Mila, C. & Kinsey, J. E.
System: The UNT Digital Library
Advances in Comprehensive Gyrokinetic Simulations of Transport in Tokamaks (open access)

Advances in Comprehensive Gyrokinetic Simulations of Transport in Tokamaks

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or a globally with physical profile variation. Rohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, plasma pinches and impurity flow, and simulations at fixed flow rather than fixed gradient are illustrated and discussed.
Date: October 1, 2004
Creator: Waltz, R. E.; Candy, J.; Hinton, F. L.; Estrada-Mila, C. & Kinsey, J. E.
System: The UNT Digital Library
Advancing the Ion Beam Thin Film Planarization Process for the Smoothing of Substrate Particles (open access)

Advancing the Ion Beam Thin Film Planarization Process for the Smoothing of Substrate Particles

This report addresses the advancement of the ion beam thin film planarization process for the smoothing of substrate particles.
Date: October 27, 2004
Creator: Mirkarimi, P.; Spiller, E.; Baker, S.; Robinson, J.; Stearns, D.; Liddle, J. A. et al.
System: The UNT Digital Library
ADVANCING THE ION BEAM THIN FILM PLANARIZATION PROCESS FOR THE SMOOTHING OF SUBSTRATE PARTICLES (open access)

ADVANCING THE ION BEAM THIN FILM PLANARIZATION PROCESS FOR THE SMOOTHING OF SUBSTRATE PARTICLES

For a number of technologies small substrate contaminants are undesirable, and for one technology in particular, extreme ultraviolet lithography (EUVL), they can be a very serious issue. We have demonstrated that the Ion Beam Thin Film Planarization Process, a coating process designed to planarize substrate asperities, can be extended to smooth {approx}70 nm and {approx}80 nm diameter particles on EUVL reticle substrates to a height of {approx}0.5 nm, which will render them noncritical in an EUVL printing process. We demonstrate this smoothing process using controlled nanoscale substrate particles and lines fabricated with an e-beam lithography process. The above smoothing process was also modified to yield an excellent reflectance/wavelength uniformity and a good EUV reflectivity for the multilayer, which is required for EUVL reticles. Cross-sectional TEM on a smoothed substrate line defect shows excellent agreement with results obtained from our multilayer growth model.
Date: October 19, 2004
Creator: Mirkarimi, P B; Spiller, E; Baker, S L; Robinson, J C; Stearns, D G; Liddle, J A et al.
System: The UNT Digital Library
Alternatives to Seesaw (open access)

Alternatives to Seesaw

The seesaw mechanism is attractive not only because it"explains'' small neutrino mass, but also because of its packaging with the SUSY-GUT, leptogenesis, Dark Matter, and electroweak symmetry breaking. However, this package has the flavor, CP, and gravitino problems. I discuss two alternatives to the seesaw mechanism. In one of them, the anomaly-mediated supersymmetry breaking solves these problems, while predicts naturally light Dirac neutrinos. In the other, the light Majorana neutrinos arise from supersymmetry breaking with right-handed neutrinos below TeV, and the Dark Matter and collider phenomenology are significantly different.
Date: October 10, 2004
Creator: Murayama, Hitoshi
System: The UNT Digital Library
Analysis of Radiation Induced Degradation in FPC-461 Fluoropolymers by Variable Temperature Multinuclear NMR (open access)

Analysis of Radiation Induced Degradation in FPC-461 Fluoropolymers by Variable Temperature Multinuclear NMR

Solid state nuclear magnetic resonance techniques have been used to investigate aging mechanisms in a vinyl chloride:chlorotrifluoroethylene copolymer, FPC-461, due to exposure to {gamma}-radiation. Solid state {sup 1}H MAS NMR spectra revealed structural changes of the polymer upon irradiation under both air and nitrogen atmospheres. Considerable degradation is seen with {sup 1}H NMR in the vinyl chloride region of the polymer, particularly in the samples irradiated in air. {sup 19}F MAS NMR was used to investigate speciation in the chlorotrifluoroethylene blocks, though negligible changes were seen. {sup 1}H and {sup 19}F NMR at elevated temperature revealed increased segmental mobility and decreased structural heterogeneity within the polymer, yielding significant resolution enhancement over room temperature solid state detection. The effects of multi-site exchange are manifest in both the {sup 1}H and {sup 19}F NMR spectra as a line broadening and change in peak position as a function of temperature.
Date: October 27, 2004
Creator: Chinn, S C; Wilson, T S & Maxwell, R S
System: The UNT Digital Library
Answering Key Fuel Cycle Questions (open access)

Answering Key Fuel Cycle Questions

Given the range of fuel cycle goals and criteria, and the wide range of fuel cycle options, how can the set of options eventually be narrowed in a transparent and justifiable fashion? It is impractical to develop all options. We suggest an approach that starts by considering a range of goals for the Advanced Fuel Cycle Initiative (AFCI) and then posits seven questions, such as whether Cs and Sr isotopes should be separated from spent fuel and, if so, what should be done with them. For each question, we consider which of the goals may be relevant to eventually providing answers. The AFCI program has both ''outcome'' and ''process'' goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geologic repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are rea diness to proceed and adaptability and robustness in the face of uncertainties.
Date: October 3, 2004
Creator: Piet, S. J.; Dixon, B. W.; Bennett, R. G.; Smith, J. D. & Hill, R. N.
System: The UNT Digital Library
APDS: The Autonomous Pathogen Detection System (open access)

APDS: The Autonomous Pathogen Detection System

We have developed and tested a fully autonomous pathogen detection system (APDS) capable of continuously monitoring the environment for airborne biological threat agents. The system was developed to provide early warning to civilians in the event of a bioterrorism incident and can be used at high profile events for short-term, intensive monitoring or in major public buildings or transportation nodes for long-term monitoring. The APDS is completely automated, offering continuous aerosol sampling, in-line sample preparation fluidics, multiplexed detection and identification immunoassays, and nucleic-acid based polymerase chain reaction (PCR) amplification and detection. Highly multiplexed antibody-based and duplex nucleic acid-based assays are combined to reduce false positives to a very low level, lower reagent costs, and significantly expand the detection capabilities of this biosensor. This article provides an overview of the current design and operation of the APDS. Certain sub-components of the ADPS are described in detail, including the aerosol collector, the automated sample preparation module that performs multiplexed immunoassays with confirmatory PCR, and the data monitoring and communications system. Data obtained from an APDS that operated continuously for seven days in a major U.S. transportation hub is reported.
Date: October 4, 2004
Creator: Hindson, Benjamin; Makarewicz, Anthony; Setlur, Ujwal; Henderer, Bruce; McBride, Mary & Dzenitis, John
System: The UNT Digital Library
Application of Ab Initio and CALPHAD Thermodynamics to Mo-Ta-W Alloys (open access)

Application of Ab Initio and CALPHAD Thermodynamics to Mo-Ta-W Alloys

None
Date: October 11, 2004
Creator: Turchi, P. A.; Drchal, V.; Kudrnovsky, J.; Colinet, C.; Kaufman, L. & Liu, Z.
System: The UNT Digital Library
Application of Multi-rate Flowing Fluid Electric ConductivityLogging Method to Well DH-2, Tono Site, Japan (open access)

Application of Multi-rate Flowing Fluid Electric ConductivityLogging Method to Well DH-2, Tono Site, Japan

The flowing fluid electric conductivity (FEC) logging method, wellbore fluid is replaced with de-ionized water, following which FEC profiles in the wellbore are measured at a series of times while the well is pumped at a constant rate. Locations were fluid enters the wellbore show peaks in the FEC logs, which may be analyzed to infer inflow strengths and salinities of permeable features intersected by the wellbore. In multi-rate flowing FEC logging, the flowing FEC logging method is repeated using two or more pumping rates, which enables the transmissivities and inherent pressure heads of these features to be estimated as well. We perform multi-rate FEC logging on a deep borehole in fractured granitic rock, using three different pumping rates. Results identify 19 hydraulically conducting fractures and indicate that transmissivity, pressure head, and salinity vary significantly among them. By using three pumping rates rather than the minimum number of two, we obtain an internal consistency check on the analysis that provides a measure of the uncertainty of the results. Good comparisons against static FEC profiles and against independent chemical, geological, and hydrogeological data have further enhanced confidence in the results of the multi-rate flowing FEC logging method.
Date: October 4, 2004
Creator: Doughty, Christine; Takeuchi, Shinji; Amano, Kenji; Shimo, Michito & Tsang, Chin-Fu
System: The UNT Digital Library
Application of SERS Nanoparticles for Intracellular pH Measurements (open access)

Application of SERS Nanoparticles for Intracellular pH Measurements

We present an alternative approach to optical probes that will ultimately allow us to measure chemical concentrations in microenvironments within cells and tissues. This approach is based on monitoring the surface-enhanced Raman scattering (SERS) response of functionalized metal nanoparticles (50-100 nm in diameter). SERS allows for the sensitive detection of changes in the state of chemical groups attached to individual nanoparticles and small clusters. Here, we present the development of a nanoscale pH meter. The pH response of these nanoprobes is tested in a cell-free medium, measuring the pH of the solution immediately surrounding the nanoparticles. Heterogeneities in the SERS signal, which can result from the formation of small nanoparticle clusters, are characterized using SERS correlation spectroscopy and single particle/cluster SERS spectroscopy. The response of the nanoscale pH meters is tested under a wide range of conditions to approach the complex environment encountered inside living cells and to optimize probe performance.
Date: October 21, 2004
Creator: Laurence, T.; Talley, C.; Colvin, M. & Huser, T.
System: The UNT Digital Library