Nerine Cherepy | Lawrence Livermore National Lab (original) (raw)

Papers by Nerine Cherepy

Research paper thumbnail of Red-emitting manganese-doped aluminum nitride phosphor

Research paper thumbnail of Direct electrochemical conversion of carbon anode fuels in molton salt media

We are conducting research into the direct electrochemical conversion of reactive carbons into el... more We are conducting research into the direct electrochemical conversion of reactive carbons into electricity--with experimental evidence of total efficiencies exceeding 80% of the heat of combustion of carbon. Together with technologies for extraction of reactive carbons from broad based fossil fuels, direct carbon conversion addresses the objectives of DOE's ''21st Century Fuel Cell'' with exceptionally high efficiency (>70% based on

Research paper thumbnail of Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in ... more ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Research paper thumbnail of Advancements in Gamma Spectrometers Based on Europium-doped Strontium Iodide and Characterization of its Gamma and Electron Response

Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu)... more Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu). SrI2(Eu) has excellent material properties for gamma ray spectroscopy: high light yield (>80,000 ph/MeV), excellent light yield proportionality, and high effective atomic number (Z=49) for high photoelectric cross-section. Through advances in SrI2(Eu) crystal growth, high quality 1.5 inch and 2 inch diameter boules have been produced. In these large SrI2(Eu) crystals, optical light trapping by Eu 2+ degrades the energy resolution as measured by analog electronics, but we mitigate this effect through on-the-fly correction of the scintillation pulses by digital readout electronics. Using this digital pulse-processing technique we have demonstrated energy resolution of <3% FWHM at 662 keV for a 4 in 3 SrI2(Eu) crystal, over 2.6 inches long. With these digital readout electronics, we are developing a prototype handheld detector to demonstrate the radioisotope identification performan...

Research paper thumbnail of Synthesis and optical properties of photochromic perinaphthothioindigo

Research paper thumbnail of Electrolyte Management for Effective Long-Term Electro-Osmotic Transport in Low-Permeability Soils

Environmental Science & Technology, 2003

Research paper thumbnail of The electrodeposition of a gold-copper composition gradient

Research paper thumbnail of <title>Ce-doped single crystal and ceramic garnet for γ-ray detection</title>

Hard X-Ray and Gamma-Ray Detector Physics IX, 2007

Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with ... more Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with bialkali photomultiplier tube detection as good as 8.6% at 662 keV. Ceramic fabrication allows production of garnets that cannot easily be grown as single crystals, such as Gadolinium Aluminum Garnet and Terbium Aluminum Garnet. Measured scintillation light yields of Cerium-doped ceramic garnets indicate prospects for high energy resolution.

Research paper thumbnail of A zinc/air fuel cell for electric vehicles

Fourteenth Annual Battery Conference on Applications and Advances. Proceedings of the Conference (Cat. No.99TH8371), 1999

Research paper thumbnail of Characterization of Vapor Deposited, NanoStructured Membranes

Research paper thumbnail of Decarboxylation of pyroglutamic acids with P2O5/CH3SO3H : A general synthesis of 5-aryl-2-pyrrolidinones

Tetrahedron Letters, 1989

Research paper thumbnail of Synthesis and optical properties of photochromic perinaphthothioindigo

Research paper thumbnail of Direct Conversion of Carbon Fuels in a Molten Carbonate Fuel Cell

Journal of The Electrochemical Society, 2005

Research paper thumbnail of Characterization of an effective cleaning procedure for aluminum alloys: surface enhanced Raman spectroscopy and zeta potential analysis

Journal of Colloid and Interface Science, 2005

Research paper thumbnail of Nature of the power-dependent ultrafast relaxation process of photoexcited charge carriers in II-VI semiconductor quantum dots: Effects of particle size, surface, and electronic structure

The Journal of Chemical Physics, 1998

The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semi... more The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semiconductor quantum dots have been studied using femtosecond laser spectroscopy. The dynamics are obtained via excitation of the quantum dots with high power 390 nm pulses of 150 fs duration, and probing of the photoexcited species by monitoring the change in absorption at 790 nm as a

Research paper thumbnail of Crystal Growth and Scintillation Properties of <formula formulatype="inline"><tex Notation="TeX">${\hbox {Cs}}_{2}{\hbox {NaCeBr}}_{6}$</tex> </formula>

IEEE Transactions on Nuclear Science, 2000

Research paper thumbnail of Electrolyte Management for Effective Long-Term Electro-Osmotic Transport in Low-Permeability Soils

Environmental Science & Technology, 2003

Research paper thumbnail of Double Salts Iodide Scintillators: Cesium Barium Iodide, Cesium Calcium Iodide, and Barium Bromine Iodide

Crystal Research and Technology, 2013

ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in pa... more ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in particular cesium barium iodide (CBI), cesium calcium iodide (CCI) and barium bromine iodide (BBI), as well as report on their scintillation and optical properties. Double salt iodides inherently have high density and atomic number which translates to good stopping power for energetic particles, in particular gamma rays. Light yields of 54,000 ph/MeV for CBI, 51,000 ph/MeV for CCI, and 46,000 ph/MeV for BBI were measured. A FWHM energy resolution for the 662 keV full absorption peak was observed at 5.7% for CBI, 16.3% for CCI and 3.56% for BBI. The principal scintillation decay timing for CBI was 840 ns, 462 ns for BBI, and two distinct time components of 9 ns and 1900 ns were observed for CCI.

Research paper thumbnail of Effective Rejection of Fluorescence Interference in Raman Spectroscopy Using a Shifted Excitation Difference Technique

Applied Spectroscopy, 1992

Research paper thumbnail of Applications of Electra-Osmotic Transport in the Processing of Textiles

Research paper thumbnail of Red-emitting manganese-doped aluminum nitride phosphor

Research paper thumbnail of Direct electrochemical conversion of carbon anode fuels in molton salt media

We are conducting research into the direct electrochemical conversion of reactive carbons into el... more We are conducting research into the direct electrochemical conversion of reactive carbons into electricity--with experimental evidence of total efficiencies exceeding 80% of the heat of combustion of carbon. Together with technologies for extraction of reactive carbons from broad based fossil fuels, direct carbon conversion addresses the objectives of DOE&amp;#39;s &amp;#39;&amp;#39;21st Century Fuel Cell&amp;#39;&amp;#39; with exceptionally high efficiency (&amp;amp;gt;70% based on

Research paper thumbnail of Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in ... more ABSTRACT A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Research paper thumbnail of Advancements in Gamma Spectrometers Based on Europium-doped Strontium Iodide and Characterization of its Gamma and Electron Response

Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu)... more Here we present recent developments in the Europium-doped Strontium Iodide scintillator, SrI2(Eu). SrI2(Eu) has excellent material properties for gamma ray spectroscopy: high light yield (>80,000 ph/MeV), excellent light yield proportionality, and high effective atomic number (Z=49) for high photoelectric cross-section. Through advances in SrI2(Eu) crystal growth, high quality 1.5 inch and 2 inch diameter boules have been produced. In these large SrI2(Eu) crystals, optical light trapping by Eu 2+ degrades the energy resolution as measured by analog electronics, but we mitigate this effect through on-the-fly correction of the scintillation pulses by digital readout electronics. Using this digital pulse-processing technique we have demonstrated energy resolution of <3% FWHM at 662 keV for a 4 in 3 SrI2(Eu) crystal, over 2.6 inches long. With these digital readout electronics, we are developing a prototype handheld detector to demonstrate the radioisotope identification performan...

Research paper thumbnail of Synthesis and optical properties of photochromic perinaphthothioindigo

Research paper thumbnail of Electrolyte Management for Effective Long-Term Electro-Osmotic Transport in Low-Permeability Soils

Environmental Science & Technology, 2003

Research paper thumbnail of The electrodeposition of a gold-copper composition gradient

Research paper thumbnail of <title>Ce-doped single crystal and ceramic garnet for γ-ray detection</title>

Hard X-Ray and Gamma-Ray Detector Physics IX, 2007

Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with ... more Ceramic and single crystal Lutetium Aluminum Garnet scintillators exhibit energy resolution with bialkali photomultiplier tube detection as good as 8.6% at 662 keV. Ceramic fabrication allows production of garnets that cannot easily be grown as single crystals, such as Gadolinium Aluminum Garnet and Terbium Aluminum Garnet. Measured scintillation light yields of Cerium-doped ceramic garnets indicate prospects for high energy resolution.

Research paper thumbnail of A zinc/air fuel cell for electric vehicles

Fourteenth Annual Battery Conference on Applications and Advances. Proceedings of the Conference (Cat. No.99TH8371), 1999

Research paper thumbnail of Characterization of Vapor Deposited, NanoStructured Membranes

Research paper thumbnail of Decarboxylation of pyroglutamic acids with P2O5/CH3SO3H : A general synthesis of 5-aryl-2-pyrrolidinones

Tetrahedron Letters, 1989

Research paper thumbnail of Synthesis and optical properties of photochromic perinaphthothioindigo

Research paper thumbnail of Direct Conversion of Carbon Fuels in a Molten Carbonate Fuel Cell

Journal of The Electrochemical Society, 2005

Research paper thumbnail of Characterization of an effective cleaning procedure for aluminum alloys: surface enhanced Raman spectroscopy and zeta potential analysis

Journal of Colloid and Interface Science, 2005

Research paper thumbnail of Nature of the power-dependent ultrafast relaxation process of photoexcited charge carriers in II-VI semiconductor quantum dots: Effects of particle size, surface, and electronic structure

The Journal of Chemical Physics, 1998

The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semi... more The power-dependent relaxation dynamics of photoexcited charge carriers in a number of II-VI semiconductor quantum dots have been studied using femtosecond laser spectroscopy. The dynamics are obtained via excitation of the quantum dots with high power 390 nm pulses of 150 fs duration, and probing of the photoexcited species by monitoring the change in absorption at 790 nm as a

Research paper thumbnail of Crystal Growth and Scintillation Properties of <formula formulatype="inline"><tex Notation="TeX">${\hbox {Cs}}_{2}{\hbox {NaCeBr}}_{6}$</tex> </formula>

IEEE Transactions on Nuclear Science, 2000

Research paper thumbnail of Electrolyte Management for Effective Long-Term Electro-Osmotic Transport in Low-Permeability Soils

Environmental Science & Technology, 2003

Research paper thumbnail of Double Salts Iodide Scintillators: Cesium Barium Iodide, Cesium Calcium Iodide, and Barium Bromine Iodide

Crystal Research and Technology, 2013

ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in pa... more ABSTRACT In this study we review the state-of-the-art for double salt iodide scintillators, in particular cesium barium iodide (CBI), cesium calcium iodide (CCI) and barium bromine iodide (BBI), as well as report on their scintillation and optical properties. Double salt iodides inherently have high density and atomic number which translates to good stopping power for energetic particles, in particular gamma rays. Light yields of 54,000 ph/MeV for CBI, 51,000 ph/MeV for CCI, and 46,000 ph/MeV for BBI were measured. A FWHM energy resolution for the 662 keV full absorption peak was observed at 5.7% for CBI, 16.3% for CCI and 3.56% for BBI. The principal scintillation decay timing for CBI was 840 ns, 462 ns for BBI, and two distinct time components of 9 ns and 1900 ns were observed for CCI.

Research paper thumbnail of Effective Rejection of Fluorescence Interference in Raman Spectroscopy Using a Shifted Excitation Difference Technique

Applied Spectroscopy, 1992

Research paper thumbnail of Applications of Electra-Osmotic Transport in the Processing of Textiles