A recent experiment using projectile fragmentation of a Au197 beam on a Be9 target, combined with the fragment recoil separator and experimental storage ring at ring at GSI, has uncovered an isomeric state in Re192 at 267(10) keV with a half-life of 60 s. The data analysis technique used to resolve the isomeric state from the ground state is discussed.
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD, *NUCLEAR ISOMERS, BERYLLIUM, FRAGMENTATION, GOLD,...
We report a simple and efficient synthetic method to prepare gold nanoparticles (AuNPs) in aqueous phase using HAuCl4 and poly(ethylene glycol) (PEG) ligands appended with bidentate anchoring groups. Our approach provides narrow size distribution nanocrystals over the size range between 1.5 and 18 nm; this range is much wider than those achieved using other small molecules and polymer ligands. The NP size was simply controlled by varying the molar ratio of Au-to-PEG ligand precursors. Further...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC OPTICAL SCIENCES DIV, *GOLD INTERMETALLICS, *GOLD,...
The primary objective of this research is to study the dispersion of the surface plasmon to correlate the physical origins or various phenomena linked to plasmonic effects. The goal is to fabricate multilayered plasmonic metamaterials and experimentally study their photonic properties when nonlinear amplifying dye molecules are imbedded in the structures.
Topics: DTIC Archive, INDIAN INST OF TECH KANPUR, *GRATINGS(SPECTRA), *PLASMONS, COMPOSITE MATERIALS,...
Density functional theory (DFT) and time-dependent DFT (TDDFT) have been employed to examine the optical absorption spectra of bare and passivated (thiolate-, phosphine-, or carboxylate-stabilized) gold and silver nanoparticles. The location of the ligands is responsible for causing splitting in the optical absorption spectra of thiolate-stabilized nanoparticles. The choice of metal and ligand affects the thermodynamic stability of the staples on the surface of the nanoparticle, and may affect...
Topics: DTIC Archive, KANSAS STATE UNIV MANHATTAN, *METALS, *OPTICAL PROPERTIES, *STRUCTURAL PROPERTIES,...
In this study hybrid nanoparticles (Pd@SiO2, Au@Gd2O3) have been synthesized and characterized. Gd2O3:Eu NPs were successfully synthesized using polyol synthetic routes. Nanoparticles with an average diameter size of 1-2 nm were produced in high yield. XPS analysis confirmed the successful coating of the nanoparticles with PEGCOOH and aminocapronic acid. Palladium nanoparticles synthesized using an aqueous route was more stable in aqueous solvent than palladium nanoparticles synthesized in the...
Topics: DTIC Archive, SOUTH AUSTRALIA UNIV MAWSON LAKES (AUSTRALIA), *GOLD, *PALLADIUM, *NANOPARTICLES,...
Gold (Au) nanoparticles (NPs) have a wide range of scientific applications due to their innate ability to efficiently bind with organic and bio molecules in conjunction with possessing excellent optical properties. In this experiment, Au NPs were synthesized and experimentally characterized via atomic force microscopy, high-resolution tunneling electron microscopy, and ultraviolet-visible spectroscopy. After characterization, the NPs were found to vary in shape but had a uniform size of 25 nm,...
Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH...
Improvement of the operating characteristics of rolling-element bearings was sought through development and implementation of MEMS (Micro Electro-Mechanical System) based strain sensors. The strain sensors developed in this program employ a piezoresistive transducer to convert changes in applied strains to output voltages with an on-chip temperature detector compensating for thermal effects in the strain measurement. Bonding of MEMS strain sensors to application substrates was accomplished with...
Topics: DTIC Archive, TIMKEN CORP CANTON OH, *ROLLER BEARINGS, CHIPS(ELECTRONICS), SUBSTRATES,...
We created gold (Au) and silver (Ag) nanoparticles by e-beam deposition on an n-type silicon substrate followed by rapid thermal annealing (RTA) under nitrogen gas. Thermal annealing was performed in two ways: first by varying temperature for a constant time and second by varying time at a constant temperature. RTA under the right eutectic temperature, which varies metal to metal, should create nano-metal particles on the substrate. These nanoparticles were characterized by optical spectroscopy...
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE,...
Improved AlNi-based ohmic contacts to p-type 4H-SiC have been achieved using low energy ion (Al+) implantation, the addition of a thin Ti layer, and a novel two-step implant activation anneal process. AlNi/Au contacts with and without Ti were studied, which resulted in contact resistivities around 1.8x10(exp -4) ohms-sq cm and 2.0x10(exp -3) ohms-sq cm, respectively. Even though these values were higher than those of the Ti/AlNi/W system, which was the focus of previous studies, the reduced...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE, *ELECTRIC...
A new technique has been developed for wirebonding mercury cadmium telluride (MCT) devices using indium spheres. Indium powder with a mesh size of 170/200 is made up of indium spheres. These spheres are used as solder between the gold pad on the MCT device and the gold ball of the wirebond. This novel technique eliminates damage that typically occurs to the MCT material under gold wirebonding pads due to force and ultrasonic power needed in wirebonding.
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE, *BONDING,...
We report the thermal conductance G of Au/Ti/graphene/SiO2 interfaces (graphene layers 1 or = n or = 10) typical of graphene transistor contacts. We find G approx. = 25 MW/sq m/K at room temperature, four times smaller than the thermal conductance of a Au/Ti/SiO2 interface, even when n = 1. We attribute this reduction to the thermal resistance of Au/Ti/graphene and graphene/SiO2 interfaces acting in series. The temperature dependence of G from 50 , or = T or = 500 K also indicates that heat is...
Topics: DTIC Archive, ILLINOIS UNIV AT URBANA DEPT OF MATERIALS SCIENCE AND ENGINEERING, *CARBON, *THERMAL...
Organo-soluble porphyrin mixed monolayer-protected gold nanorods were synthesized and characterized. The resulting gold nanorods encapsulated by both porphyrin thiol and alkyl thiol on their entire surface with strong covalent Au-S linkages were very stable in organic solvents without aggregation or decomposition, and exhibited unique optical properties different from their corresponding spherical ones. Alkyl thiol acts as a stabilizer not only to fill up the potential space on gold nanorod...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING...
Metal nanoclusters have interesting steady state fluorescence emission, two-photon excited emission and ultrafast dynamics. A new subclass of fluorescent silver nanoclusters (Ag NCs) are NanoCluster Beacons. NanoCluster Beacons consist of a weakly emissive Ag NC templated on a single stranded DNA (Ag NC on ssDNA'') that becomes highly fluorescent when a DNA enhancer sequence is brought in proximity to the Ag NC by DNA base pairing (Ag NC on dsDNA''). Steady state fluorescence was observed at...
Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR DEPT OF CHEMISTRY, *DEOXYRIBONUCLEIC ACIDS, *EMISSION,...
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE,...
Density functional theory (DFT) and time-dependent DFT (TDDFT) have been employed to examine the optical absorption spectra of bare and passivated (thiolate-, phosphine-, or carboxylate-stabilized) gold and silver nanoparticles. The location of the ligands is responsible for causing splitting in the optical absorption spectra of thiolate-stabilized nanoparticles. The choice of metal and ligand affects the thermodynamic stability of the staples on the surface of the nanoparticle, and may affect...
Topics: DTIC Archive, KANSAS STATE UNIV MANHATTAN, *GOLD, *NANOPARTICLES, *OPTICAL PROPERTIES, *SILVER,...
Multiwalled carbon nanotubes (MWCNTs) were functionalized with 4-mercaptobenzoic acid in a polyphosphoric acid/phosphorous pentoxide medium to produce 4-mercaptobenzoyl-functionalized MWCNTs (MB-MWCNTs). Gold nanoparticles (GNPs), stabilized by trisodium citrate, were prepared from the in-situ reduction of gold(III) chloride trihydrate by sodium borohydride in the presence of MB-MWCNTs dispersed in ethanol. The morphology of the resulting GNP/MB-MWCNT hybrid showed that GNPs were formed with an...
Topics: DTIC Archive, ULSAN NATIONAL INSTITUTE OF SCIENCE AND TECHNOLOGY (KOREA SOUTH), *CARBON NANOTUBES,...
Various aspects of plasmonic catalysis, including plasmon enhanced catalysis, plasmonic sensing of catalysis and surface plasmon driven hot electron flow were explored. Light trapping from nanostructured Au nanopillars and their surface plasmon enhanced the photocurrent of an iron oxide photoanode by more than 50% across the solar spectrum. Two platforms for in situ plasmon enhanced spectroscopy of catalytic intermediates were demonstrated. Firstly, single particle hydrogen storage trajectories...
Topics: DTIC Archive, CALIFORNIA UNIV BERKELEY, *CATALYSIS, *PLASMONS, GOLD, HYDROGEN STORAGE, IRON OXIDES,...
Glucose oxidase catalyzes the formation of metallic gold particles in immediate proximity of the protein from gold (III) chloride in the absence of any other catalytic or reductive substrates. The protein-mediated gold reduction reaction leads to size-controllable gold particle formation and concomitant association of the enzyme in an electrically conductive metallic template. Such an enzyme immobilization strategy provides a simple and rapid method to create an intimate interface between...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB TYNDALL AFB FL, *GLUCOSE, *GOLD, *NANOSTRUCTURES,...
Semiconductor quantum dots (QDs) and metal nanoparticles (NPs) have attracted a great deal of attention in the biology community due to their application as fluorescent labels and sensors. The optical properties of NPs allow them to be effective imaging agents for biomolecules. Their biological sensing abilities include identifying target DNA through a linker, followed by color change and electrical signaling. However, size-controlled NPs have the potential to be used as more than just sensors...
Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, *DEOXYRIBONUCLEIC ACIDS, OPTICAL...
We have studied the adsorption of molecular water at the (111) surface of cerium dioxide (CeO2) singe crystals by means of atomic force microscopy (AFM) working with atomic resolution. Our AFM data reveal that single molecular water does not dissociate upon adsorption at the bare CeO2(111) surface, but it remains stably adsorbed at the surface over the temperature rage in which we have performed this study (300K to 10K). We have been able to manipulate individual water molecules with the tip of...
Topics: DTIC Archive, NATIONAL INST FOR MATERIALS SCIENCE TSUKUBA IBARAKI (JAPAN), *CERIUM COMPOUNDS,...
It has been a long-standing goal to create magnetism in a non-magnetic material by manipulating its structure at the nanoscale. Many structural defects have unpaired spins; an ordered arrangement of these can create a magnetically ordered state. In this article we predict theoretically that stepped silicon surfaces stabilized by adsorbed gold achieve this state by self assembly, creating chains of polarized electron spins with atomically precise structural order. The spins are localized at...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR COMPUTATIONAL MATERIALS SCIENCE,...
Due to their unique plasmonic and optical properties, gold nanorods (GNR) have shown tremendous potential for nano-based applications extending into a variety of fields including bio-imaging, sensor development, electronics, and cancer therapy. These distinctive, shape-specific properties are strongly dependent upon the GNR aspect ratio, thus producing the ability to be targeted for an application by fine-tuning their physical parameters. It is owing to their characteristic spectral signature,...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN PERFORMANCE WING (711TH) HUMAN...
The purpose of this project is to study the lifetime and annihilation mode of positrons, the antimatter counterpart to electrons, and the formation rate of positronium on a gold surface modified by gold nanoparticles under the influence of radial electric fields measured using two independent systems. The positron annihilation photon pair/triplet spectroscopy system uses a sodium iodide ring detector segmented into six detection regions providing rough position sensitivity to measure the ratio...
Topics: DTIC Archive, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND...
We briefly reviewed the current knowledge of organics that may be present on the surface of Mars providing some clue as to what to expect in terms of meaningful detection. We briefly discussed the well known capabilities of Raman spectroscopy applicable to astrobiology exploration on Mars. Finally, details of potential limit to the implementation of SERS are discussed.
Topics: DTIC Archive, HAMPTON UNIV VA, *MARS(PLANET), *SPACE BIOLOGY, *SURFACE PROPERTIES, AQUEOUS...
During the current project, we have identified classes of stable cluster motifs for implementation as building blocks of nanoenergetic materials and developed guiding principles for their synthesis. To begin, differing mechanisms that can stabilize clusters were identified. The first refers to crystal field like splitting of electronic shells via geometrical distortions that can lead to stable species at sub-shell fillings. Such a mechanism accounted for the stability of CuAl22- and more...
Topics: DTIC Archive, VIRGINIA COMMONWEALTH UNIV RICHMOND, *ALUMINUM, *CATALYSIS, *CLUSTERING, *PROPULSION...
Fabrication of sphere-like Au nanoparticles (NPs) of fixed orientation on sapphire, GaN, and SiO2 substrates through the irradiation of a few pulses of 266-nm laser onto Au thin films deposited on the substrates was demonstrated. Numerical simulations based on the finite-element method using the experimental parameters show highly consistent localized surface plasmon resonance spectral positions and their variation trends. From the simulation results, one can also observe the relative...
Topics: DTIC Archive, NATIONAL TAIWAN UNIV TAIPEI (TAIWAN) GRADUATE INST OF ELECTRO-OPTICAL ENGINEERING,...
A detection system for theophylline that combined the recognition properties of an aptamer and that plasmonic response of gold nanoparticles (AuNPs) is presented. The aptamer was used as a linker for AuNPs functionalized with complementary sequences to the aptamer (DNA-AuNPs), producing supramolecular complexes that disassemble when exposed to theophylline due to aptamer binding. The detection event was reported as a change in the AuNPs plasmonic peak and intensity. Addition of a spacer on the...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN EFFECTIVENESS DIRECTORATE...
We report on the chemical synthesis, structural and compositional characterization, and hierarchical organization of Co-core, concentric CoO Au multi-shell nanocrystals (Co@CoO@Au). Based on electron microscopy, magnetometry and spectroscopy experiments, we present compelling evidence for the formation of the Au outer shell on CoO, challenging the common assumption that the reduction reaction to form Au shells can only occur if the cobalt surface has not oxidized. Our findings suggest that the...
Topics: DTIC Archive, DREXEL UNIV PHILADELPHIA PA DEPT OF MATERIALS SCIENCE AND ENGINEERING, *COBALT,...
The objective of this investigation was to explore the ability of a radio frequency (RF) signal to interact with metal nanoparticles for the purposes of remote stimulation or control of cellular processes. For this study, spherical gold nanoparticles (Au NPs, 4nm and 13 nm) and spherical silver nanoparticles (Ag NPs, 8nm) were synthesized, biofunctionalized with oligonucleotides, and hybridized through the oligonucleotide functionalization as a potential method of intracellular control. Initial...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN EFFECTIVENESS DIRECTORATE,...
This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleiuc acid (RNA) sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface,...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT PATTERSON AFB OH HUMAN PERFORMANCE WING (711TH) HUMAN...
The final goal of this project is to develop smart particles to stop internal hemorrhage at local sites. Four collaborating laboratories are working together under this contract to define threshold levels of activators of blood clotting such that the candidate clotting activators will circulate in the blood at a concentration below the threshold necessary to trigger clotting, but accumulation of the activators at sites of internal injury/bleeding will cause the local concentration of clotting...
Topics: DTIC Archive, ILLINOIS UNIV CHAMPAIGN, *BLOOD COAGULATION, *HEMORRHAGE, *INORGANIC POLYMERS,...
Gold nanorods (GNRs) are of interest in many biological applications, including drug delivery and biomedical imaging due to their unique optical properties and the versatility for surface modification. For use in such applications, it is important to understand the effect of surface chemistry on the toxicological effects of GNRs to cells. In the current study, GNR stabilized with cetyltrimethylammonium bromide (GNR-CTAB) and GNR functionalized via a ligand exchange method with either thiolated...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN EFFECTIVENESS DIRECTORATE,...
Advances in lithium primary battery technology, which serves as the gold standard power source for the dismounted soldier, have not kept pace with the ever increasing power and energy requirements of modern military electronic equipment. Fuel cells have long been touted as the solution to the dismounted soldier's power and energy problems, but until recently, have largely failed to live up to that promise. There is still a pressing need for better power sources at the Watt or sub-Watt level,...
Topics: DTIC Archive, HONEYWELL INC MINNEAPOLIS MN HONEYWELL LABORATORIES, *FIBERS, *FUEL CELLS, *LITHIUM...
