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Sample records for fbtr hybrid core

  1. Carbon nanotube core graphitic shell hybrid fibers.

    PubMed

    Hahm, Myung Gwan; Lee, Jae-Hwang; Hart, Amelia H C; Song, Sung Moo; Nam, Jaewook; Jung, Hyun Young; Hashim, Daniel Paul; Li, Bo; Narayanan, Tharangattu N; Park, Chi-Dong; Zhao, Yao; Vajtai, Robert; Kim, Yoong Ahm; Hayashi, Takuya; Ku, Bon-Cheol; Endo, Morinobu; Barrera, Enrique; Jung, Yung Joon; Thomas, Edwin L; Ajayan, Pulickel M

    2013-12-23

    A carbon nanotube yarn core graphitic shell hybrid fiber was fabricated via facile heat treatment of epoxy-based negative photoresist (SU-8) on carbon nanotube yarn. The effective encapsulation of carbon nanotube yarn in carbon fiber and a glassy carbon outer shell determines their physical properties. The higher electrical conductivity (than carbon fiber) of the carbon nanotube yarn overcomes the drawbacks of carbon fiber/glassy carbon, and the better properties (than carbon nanotubes) of the carbon fiber/glassy carbon make up for the lower thermal and mechanical properties of the carbon nanotube yarn via synergistic hybridization without any chemical doping and additional processes. PMID:24224730

  2. Hybrid Analysis of Engine Core Noise

    NASA Astrophysics Data System (ADS)

    O'Brien, Jeffrey; Kim, Jeonglae; Ihme, Matthias

    2015-11-01

    Core noise, or the noise generated within an aircraft engine, is becoming an increasing concern for the aviation industry as other noise sources are progressively reduced. The prediction of core noise generation and propagation is especially challenging for computationalists since it involves extensive multiphysics including chemical reaction and moving blades in addition to the aerothermochemical effects of heated jets. In this work, a representative engine flow path is constructed using experimentally verified geometries to simulate the physics of core noise. A combustor, single-stage turbine, nozzle and jet are modeled in separate calculations using appropriate high fidelity techniques including LES, actuator disk theory and Ffowcs-Williams Hawkings surfaces. A one way coupling procedure is developed for passing fluctuations downstream through the flowpath. This method effectively isolates the core noise from other acoustic sources, enables straightforward study of the interaction between core noise and jet exhaust, and allows for simple distinction between direct and indirect noise. The impact of core noise on the farfield jet acoustics is studied extensively and the relative efficiency of different disturbance types and shapes is examined in detail.

  3. Evolution of a Hybrid Roller Cone/PDC core bit

    SciTech Connect

    Pettitt, R.; Laney, R.; George, D.; Clemens, G.

    1980-01-01

    The development of the hot dry rock (HDR) geothermal resource, as presently being accomplished by the Los Alamos Scientific Laboratory (LASL), requires that sufficient quantities of good quality core be obtained at a reasonable cost. The use of roller cone core bits, with tungsten carbide inserts, was initiated by the Deep Sea Drilling Program. These bits were modified for continental drilling in deep, hot, granitic rock for the LASL HDR Geothermal Site at Fenton Hill, New Mexico in 1974. After the advent of monocrystalline diamond Stratapax pads, a prototype hybrid roller cone/Stratapax core bit was fabricated by Smith Tool, and tested at Fenton Hill in 1978. During the drilling for a deeper HDR reservoir system in 1979 and 1980, six of the latest generation of these bits, now called Hybrid Roller Cone/Polycrystalline Diamond Cutter (PDC) core bits, were successfully used in granitic rock at depths below 11,000 ft.

  4. Coring Methane Hydrate by using Hybrid Pressure Coring System of D/V Chikyu

    NASA Astrophysics Data System (ADS)

    Kubo, Y.; Mizuguchi, Y.; Inagaki, F.; Eguchi, N.; Yamamoto, K.

    2013-12-01

    Pressure coring is a technique to keep in-situ conditions in recovering sub-seafloor sediment samples, which are potentially rich in soluble or hydrated gas. In regular core sampling, gas fractions are easily lost through the changes in the pressure and temperature during core recovery, and it has significant impact on the chemical components of the sample. Rapid degassing may also cause critical damages of original structures. To study original characteristics of gaseous sub-seafloor sediment, a new Hybrid Pressure Coring System (Hybrid PCS) was developed for the D/V Chikyu operation by adapting some of the existing pressure sampling technologies. Hybrid PCS is composed of three main parts: top section for the wireline operation, middle section for the accumulator and pressure controlling system, and the bottom section for the autoclave chamber. The design concept is based on that of Pressure Core Sampler used in Ocean Drilling Program, and of Pressure Temperature Core Sampler (PTCS) and Non-cooled PTCS of Japan Oil, Gas and Metals National Corporation (JOGMEC). Several modifications were made including that on the ball valve, which operates to close the autoclave after coring. The core samples are 51 mm in diameter and up to 3.5 m in length. The system is combined with the Extented Shoe Coring System on the Chikyu and best suited for coring of semi-consolidated formation up to about 3400 m from the sea level. Sample autoclave is compatible with Pressure Core Analysis and Transfer System (PCATS) of Geotek Ltd for sub-sampling and analysis under in-situ pressure. The analysis in PCATS includes X-ray CT scan and core logging with P-wave velocity and gamma density. Depressurization provides accurate volume of gas and its sub-sampling. Hybrid PCS was first tested during the Chikyu Exp. 906 at a submarine mud-volcano in the Nankai Trough. A 0.9 m of hydrate rich material was recovered from the summit (water depth: 2000 m) and the intact hydrate structure was observed

  5. Explosion of white dwarfs harboring hybrid CONe cores

    NASA Astrophysics Data System (ADS)

    Bravo, E.; Gil-Pons, P.; Gutiérrez, J. L.; Doherty, C. L.

    2016-05-01

    Recently, it has been found that off-center carbon burning in a subset of intermediate-mass stars does not propagate all the way to the center, resulting in a class of hybrid CONe cores. The implications of a significant presence of carbon in the resulting massive degenerate cores have not been thoroughly explored so far. Here, we consider the possibility that stars hosting these hybrid CONe cores might belong to a close binary system and, eventually, become white dwarfs accreting from a nondegenerate companion at rates leading to a supernova explosion. We computed the hydrodynamical phase of the explosion of Chandrasekhar-mass white dwarfs harboring hybrid cores, assuming that the explosion starts at the center; this explosion occurs either as a detonation, as may be expected in some degenerate merging scenarios, or as a deflagration that afterward transitions into a delayed detonation. We assume these hybrid cores are made of a central CO volume, of mass MCO, surrounded by an ONe shell. We show that, in the case of a pure detonation, a medium-sized carbon-rich region, MCO (<0.4 M⊙), results in the ejection of a small fraction of the mantle while leaving a massive bound remnant. Part of this remnant is made of the products of the detonation, that is, Fe-group nuclei, but they are buried in its inner regions unless convection is activated during the ensuing cooling and shrinking phase of the remnant. In contrast, and somehow paradoxically, delayed detonations do not leave remnants other than for the minimum MCO we explored of MCO = 0.2 M⊙, and even in this case the remnant is as small as 0.13 M⊙. The ejecta produced by these delayed detonations are characterized by slightly smaller masses of 56Ni and substantially smaller kinetic energies than the ejecta obtained for a delayed detonation of a "normal" CO white dwarf. The optical emission expected from these explosions most likely do not match the observational properties of typical Type Ia supernovae

  6. Explosion of white dwarfs harboring hybrid CONe cores

    NASA Astrophysics Data System (ADS)

    Bravo, E.; Gil-Pons, P.; Gutiérrez, J. L.; Doherty, C. L.

    2016-04-01

    Recently, it has been found that off-center carbon burning in a subset of intermediate-mass stars does not propagate all the way to the center, resulting in a class of hybrid CONe cores. The implications of a significant presence of carbon in the resulting massive degenerate cores have not been thoroughly explored so far. Here, we consider the possibility that stars hosting these hybrid CONe cores might belong to a close binary system and, eventually, become white dwarfs accreting from a nondegenerate companion at rates leading to a supernova explosion. We computed the hydrodynamical phase of the explosion of Chandrasekhar-mass white dwarfs harboring hybrid cores, assuming that the explosion starts at the center; this explosion occurs either as a detonation, as may be expected in some degenerate merging scenarios, or as a deflagration that afterward transitions into a delayed detonation. We assume these hybrid cores are made of a central CO volume, of mass MCO, surrounded by an ONe shell. We show that, in the case of a pure detonation, a medium-sized carbon-rich region, MCO (<0.4 M⊙), results in the ejection of a small fraction of the mantle while leaving a massive bound remnant. Part of this remnant is made of the products of the detonation, that is, Fe-group nuclei, but they are buried in its inner regions unless convection is activated during the ensuing cooling and shrinking phase of the remnant. In contrast, and somehow paradoxically, delayed detonations do not leave remnants other than for the minimum MCO we explored of MCO = 0.2 M⊙, and even in this case the remnant is as small as 0.13 M⊙. The ejecta produced by these delayed detonations are characterized by slightly smaller masses of 56Ni and substantially smaller kinetic energies than the ejecta obtained for a delayed detonation of a "normal" CO white dwarf. The optical emission expected from these explosions most likely do not match the observational properties of typical Type Ia supernovae

  7. Hybrid method for ex-core detector response

    SciTech Connect

    Emert, C.J.; Freeman, L.B.; Tessler, G.

    1997-04-01

    Calculations have been completed to predict currents for ion chambers located in a shield tank exterior to a reactor vessel. The detector response is best described using a Monte Carlo transport theory calculation showing the detailed detector region geometry. To save computer time, a hybrid method has been used, whereby neutron attenuation between the core and the shield tank is calculated by deterministic methods and the results are spliced to the Monte Carlo detector calculation. The approach used has the effect of separating the detailed description of the neutron source distribution in the core from the detailed Monte Carlo description of the neutron detector environment. Comparisons have been made to measurements and to calculations using a purely Monte Carlo approach.

  8. Fabrication of novel core-shell hybrid alginate hydrogel beads.

    PubMed

    Liu, Hongxia; Wang, Chaoyang; Gao, Quanxing; Liu, Xinxing; Tong, Zhen

    2008-03-01

    Novel hybrid alginate hydrogel beads with shells of porous CaCO3 microparticles were fabricated by templating water-in-oil emulsion and subsequent in situ gelation. Porous CaCO3 microparticles were self-assembled at interfaces of water-in-oil emulsion. Water droplets containing alginate in the emulsion were subsequently in situ gelated by Ca2+ released from CaCO3 through decreasing pH with slow hydrolysis of d-glucono-delta-lactone (GDL). The resulting hybrid beads with alginate gel cores and shells of porous CaCO3 microparticles were called colloidosomes. The packed density of CaCO3 microparticles in the shell increased with increasing the ratio of the CaCO3 microparticle weight to the water phase volume Mp/Vw and decreased with addition of NaCl into water. The size of the produced colloidosome beads was independent of Mp/Vw. Increasing the volume fraction of water Phi w to 0.5, some colloidosome beads deformed to nonspheral shape and even broken. Brilliant blue (BB) as a drug model was loaded into the colloidosome beads by being dissolved in the alginate aqueous solution before gelation. The BB release from the colloidosome beads was slowed down because of the formation of the shells of CaCO3 microparticles. The colloidosome beads may find applications as delivery vehicles for drugs, cosmetics, food supplements and living cell. PMID:17964745

  9. Facile preparation of hybrid core-shell nanorods for photothermal and radiation combined therapy.

    PubMed

    Deng, Yaoyao; Li, Erdong; Cheng, Xiaju; Zhu, Jing; Lu, Shuanglong; Ge, Cuicui; Gu, Hongwei; Pan, Yue

    2016-02-11

    The hybrid platinum@iron oxide core-shell nanorods with high biocompatibility were synthesized and applied for combined therapy. These hybrid nanorods exhibit a good photothermal effect on cancer cells upon irradiation with a NIR laser. Furthermore, due to the presence of a high atomic number element (platinum core), the hybrid nanorods show a synergistic effect between photothermal and radiation therapy. Therefore, the as-prepared core-shell nanorods could play an important role in facilitating synergistic therapy between photothermal and radiation therapy to achieve better therapeutic efficacy. PMID:26818657

  10. Polystyrene-Core-Silica-Shell Hybrid Particles Containing Gold and Magnetic Nanoparticles.

    PubMed

    Tian, Jia; Vana, Philipp

    2016-02-18

    Polystyrene-core-silica-shell hybrid particles were synthesized by combining the self-assembly of nanoparticles and the polymer with a silica coating strategy. The core-shell hybrid particles are composed of gold-nanoparticle-decorated polystyrene (PS-AuNP) colloids as the core and silica particles as the shell. PS-AuNP colloids were generated by the self-assembly of the PS-grafted AuNPs. The silica coating improved the thermal stability and dispersibility of the AuNPs. By removing the "free" PS of the core, hollow particles with a hydrophobic cage having a AuNP corona and an inert silica shell were obtained. Also, Fe3O4 nanoparticles were encapsulated in the core, which resulted in magnetic core-shell hybrid particles by the same strategy. These particles have potential applications in biomolecular separation and high-temperature catalysis and as nanoreactors. PMID:26639677

  11. Facile preparation of hybrid core-shell nanorods for photothermal and radiation combined therapy

    NASA Astrophysics Data System (ADS)

    Deng, Yaoyao; Li, Erdong; Cheng, Xiaju; Zhu, Jing; Lu, Shuanglong; Ge, Cuicui; Gu, Hongwei; Pan, Yue

    2016-02-01

    The hybrid platinum@iron oxide core-shell nanorods with high biocompatibility were synthesized and applied for combined therapy. These hybrid nanorods exhibit a good photothermal effect on cancer cells upon irradiation with a NIR laser. Furthermore, due to the presence of a high atomic number element (platinum core), the hybrid nanorods show a synergistic effect between photothermal and radiation therapy. Therefore, the as-prepared core-shell nanorods could play an important role in facilitating synergistic therapy between photothermal and radiation therapy to achieve better therapeutic efficacy.The hybrid platinum@iron oxide core-shell nanorods with high biocompatibility were synthesized and applied for combined therapy. These hybrid nanorods exhibit a good photothermal effect on cancer cells upon irradiation with a NIR laser. Furthermore, due to the presence of a high atomic number element (platinum core), the hybrid nanorods show a synergistic effect between photothermal and radiation therapy. Therefore, the as-prepared core-shell nanorods could play an important role in facilitating synergistic therapy between photothermal and radiation therapy to achieve better therapeutic efficacy. Electronic supplementary information (ESI) available: Details of general experimental procedures. See DOI: 10.1039/c5nr09102k

  12. Fabrication of Te@Au core-shell hybrids for efficient ethanol oxidation

    NASA Astrophysics Data System (ADS)

    Jin, Huile; Wang, Demeng; Zhao, Yuewu; Zhou, Huan; Wang, Shun; Wang, Jichang

    2012-10-01

    Using Au nanoparticles to catalyze the oxidation of alcohols has garnered increasing attention due to its potential application in direct alcohol fuel cells. In this research Te@Au core-shell hybrids were fabricated for the catalytic oxidation of ethanol, where the preparation procedure involved the initial production of Te crystals with different microstructures and the subsequent utilization of the Te crystal as a template and reducing agent for the production of Te@Au hybrids. The as-prepared core-shell hybrids were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. Electrochemical measurements illustrate that the hybrids have great electrocatalytic activity and stability toward ethanol oxidation in alkaline media. The enhanced electrocatalytic property may be attributed to the cooperative effects between the metal and semiconductor and the presence of a large number of active sites on the hybrids surface.

  13. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-07-12

    This work studies the performance and scalability characteristics of"hybrid'"parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  14. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-06-14

    This work studies the performance and scalability characteristics of"hybrid" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  15. MPI-hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-03-20

    This work studies the performance and scalability characteristics of"hybrid'" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  16. An evaluation of MPI message rate on hybrid-core processors

    DOE PAGESBeta

    Barrett, Brian W.; Brightwell, Ron; Grant, Ryan; Hammond, Simon D.; Hemmert, K. Scott

    2014-11-01

    Power and energy concerns are motivating chip manufacturers to consider future hybrid-core processor designs that may combine a small number of traditional cores optimized for single-thread performance with a large number of simpler cores optimized for throughput performance. This trend is likely to impact the way in which compute resources for network protocol processing functions are allocated and managed. In particular, the performance of MPI match processing is critical to achieving high message throughput. In this paper, we analyze the ability of simple and more complex cores to perform MPI matching operations for various scenarios in order to gain insightmore » into how MPI implementations for future hybrid-core processors should be designed.« less

  17. An evaluation of MPI message rate on hybrid-core processors

    SciTech Connect

    Barrett, Brian W.; Brightwell, Ron; Grant, Ryan; Hammond, Simon D.; Hemmert, K. Scott

    2014-11-01

    Power and energy concerns are motivating chip manufacturers to consider future hybrid-core processor designs that may combine a small number of traditional cores optimized for single-thread performance with a large number of simpler cores optimized for throughput performance. This trend is likely to impact the way in which compute resources for network protocol processing functions are allocated and managed. In particular, the performance of MPI match processing is critical to achieving high message throughput. In this paper, we analyze the ability of simple and more complex cores to perform MPI matching operations for various scenarios in order to gain insight into how MPI implementations for future hybrid-core processors should be designed.

  18. Hybrid Parallelism for Volume Rendering on Large, Multi- and Many-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2011-01-01

    With the computing industry trending towards multi- and many-core processors, we study how a standard visualization algorithm, ray-casting volume rendering, can benefit from a hybrid parallelism approach. Hybrid parallelism provides the best of both worlds: using distributed-memory parallelism across a large numbers of nodes increases available FLOPs and memory, while exploiting shared-memory parallelism among the cores within each node ensures that each node performs its portion of the larger calculation as efficiently as possible. We demonstrate results from weak and strong scaling studies, at levels of concurrency ranging up to 216,000, and with datasets as large as 12.2 trillion cells. The greatest benefit from hybrid parallelism lies in the communication portion of the algorithm, the dominant cost at higher levels of concurrency. We show that reducing the number of participants with a hybrid approach significantly improves performance.

  19. Streamline Integration using MPI-Hybrid Parallelism on a Large Multi-Core Architecture

    SciTech Connect

    Camp, David; Garth, Christoph; Childs, Hank; Pugmire, Dave; Joy, Kenneth I.

    2010-11-01

    Streamline computation in a very large vector field data set represents a significant challenge due to the non-local and datadependentnature of streamline integration. In this paper, we conduct a study of the performance characteristics of hybrid parallel programmingand execution as applied to streamline integration on a large, multicore platform. With multi-core processors now prevalent in clustersand supercomputers, there is a need to understand the impact of these hybrid systems in order to make the best implementation choice.We use two MPI-based distribution approaches based on established parallelization paradigms, parallelize-over-seeds and parallelize-overblocks,and present a novel MPI-hybrid algorithm for each approach to compute streamlines. Our findings indicate that the work sharing betweencores in the proposed MPI-hybrid parallel implementation results in much improved performance and consumes less communication andI/O bandwidth than a traditional, non-hybrid distributed implementation.

  20. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    PubMed Central

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-01-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization. PMID:26238042

  1. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    NASA Astrophysics Data System (ADS)

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-08-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization.

  2. Surface mode hybridization in the optical response of core-shell particles

    NASA Astrophysics Data System (ADS)

    Thiessen, E.; Heinisch, R. L.; Bronold, F. X.; Fehske, H.

    2016-03-01

    We present an exact rewriting of the Mie coefficients describing the scattering of light by a spherical core-shell particle which enables their interpretation in terms of a hybridization of the two surface modes arising, respectively, at the core-shell and the shell-medium interface. For this particular case, we thus obtain from the Mie theory—analytically for all multipole orders and hence for arbitrarily sized particles—the hybridization scenario, which so far has been employed primarily for small particles in the electrostatic approximation. To demonstrate the strength of the rewriting approach, we also extract the hybridization scenario for a stratified sphere directly from the expansion coefficients for the electromagnetic fields.

  3. Progress towards accelerating HOMME on hybrid multi- core systems

    SciTech Connect

    Archibald, Richard K; Carpenter, Ilene L; Evans, Katherine J; Larkin, Jeff; Micikevicius, Paulius; Rosinski, James; Schwarzmeier, James L; Taylor, Mark

    2011-01-01

    The suitability of a spectral element based dynamical core (HOMME) within the Community Atmospheric Model (CAM) for GPU-based architectures is examined and initial performance results are reported. This work was done within a project to enable CAM to run at high resolution on next generation, multi-petaflop systems. The dynamical core is the present focus because it dominates the performance profile of our target problem. HOMME enjoys good scalability due to its underlying cubed-sphere mesh with full two-dimensional decomposition and the localization of all computational work within each element. The thread blocking and code changes that allow HOMME to effectively use GPUs are described along with a rewritten vertical remapping scheme which improves performance on both CPUs and GPUs. Validation of results in the full HOMME model is also described. Remaining issues affecting performance include optimizing the boundary exchanges for the case of multiple spectral elements being computed on the GPU and using multiple CUDA streams to overlap data transfers with computations.

  4. Hierarchically Organized Peptide Core-Silica Shell Hybrids

    NASA Astrophysics Data System (ADS)

    Altunbas, Aysegul; Sharma, Nikhil; Pochan, Darrin J.

    2009-03-01

    A biomimetic approach was applied for the fabrication of a 3D hybrid network that displays hierarchical organization of an inorganic layer around an organic self-assembled peptide fibril template. The 20 amino acid peptide used in this study consisted of alternating hydrophilic (lysine) and hydrophobic (valine) residues flanking a four amino acid turn sequence in the center. After intramolecular folding into a beta-hairpin conformation on addition of a desired solution stimulus, this peptide self-assembles into a 3D network of entangled fibrils rich in beta-sheet with a high density of lysine groups exposed on the fibril-surfaces. The lysine-rich surface chemistry was utilized to create a silica shell around the fibrils. The mineralization process of the fibrils was initiated under physiological conditions by adding the silica precursor, tetramethyl orthosilicate, to the pre-assembled hydrogel, which results in a porous silica network that retains the mesoscale structure of the peptide fibril network. Structural characterization via Transmission Electron Microscopy, cryogenic-Scanning Electron Microscopy, Small Angle Neutron and X-ray Scattering and mechanical characterization via oscillatory rheology will be presented.

  5. A facile route to synthesize core/shell structured carbon/magnetic nanoparticles hybrid and their magnetic properties

    SciTech Connect

    Qi, Xiaosi; Xu, Jianle; Zhong, Wei; Du, Youwei

    2015-07-15

    Graphical abstract: Controllable synthesis of core/shell structured carbon/magnetic nanoparticles hybrid and their tunable magnetic properties. - Highlights: • The paper reports a simple route for core/shell structured carbon/magnetic nanoparticles hybrid. • By controlling the temperature, Fe{sub 3}O{sub 4}@CNCs, Fe@HCNTs and Fe@LCNTs were produced selectively. • The magnetic properties of the obtained core/shell structured hybrid could be tuned effectively. - Abstract: By controlling the pyrolysis temperature, core/shell structured Fe{sub 3}O{sub 4}/carbon nanocages, Fe/helical carbon nanotubes and Fe/low helicity of carbon nanotubes could be synthesized selectively over Fe{sub 2}O{sub 3} nanotubes generated by a hydrothermal method. The transmission electron microscopic and scanning electron microscopic investigations revealed that the efficiency of generating core/shell structured hybrid was high, exceeding 90%. Because of the magnetic nanoparticles tightly wrapped in graphitic layers, the obtained core/shell structured hybrids showed high stability and good magnetic properties. And the magnetic properties of the obtained core/shell structured hybrid could be tuned by the decomposition temperature and time. Therefore, a simple, inexpensive and environment-benign route was proposed to produce magnetism-tunable core/shell structured hybrid in large quantities.

  6. Hybrid expert system implementation to determine core reload patterns

    SciTech Connect

    Greek, K.J.; Robinson, A.H.

    1989-01-01

    Determining reactor reload fuel patterns is a computationally intensive problem solving process for which automation can be of significant benefit. Often much effort is expended in the search for an optimal loading. While any modern programming language could be used to automate solution, the specialized tools of artificial intelligence (AI) are the most efficient means of introducing the fuel management expert's knowledge into the search for an optimum reload pattern. Prior research in pressurized water reactor refueling strategies developed FORTRAN programs that automated an expert's basic knowledge to direct a search for an acceptable minimum peak power loading. The dissatisfaction with maintenance of compiled knowledge in FORTRAN programs has served as the motivation for the development of the SHUFFLE expert system. SHUFFLE is written in Smalltalk, an object-oriented programming language, and evaluates loadings as it generates them using a two-group, two-dimensional nodal power calculation compiled in a personal computer-based FORTRAN. This paper reviews the object-oriented representation developed to solve the core reload problem with an expert system tool and its operating prototype, SHUFFLE.

  7. Core micro-instability analysis of JET hybrid and baseline discharges with carbon wall

    NASA Astrophysics Data System (ADS)

    Moradi, S.; Pusztai, I.; Voitsekhovitch, I.; Garzotti, L.; Bourdelle, C.; Pueschel, M. J.; Lupelli, I.; Romanelli, M.; JET-EFDA Contributors, the

    2014-12-01

    The core micro-instability characteristics of hybrid and baseline plasmas in a selected set of JET plasmas with carbon wall are investigated through local linear and non-linear and global linear gyro-kinetic simulations with the GYRO code (Candy and Belli 2011 General Atomics Report GA-A26818). In particular, we study the role of plasma pressure on the micro-instabilities, and scan the parameter space for the important plasma parameters responsible for the onset and stabilization of the modes under experimental conditions. We find that a good core confinement due to strong stabilization of the micro-turbulence driven transport can be expected in the hybrid plasmas due to the stabilizing effect of the fast ion pressure that is more effective at the low magnetic shear of the hybrid discharges. While parallel velocity gradient destabilization is important for the inner core, at outer radii the hybrid plasmas may benefit from a strong quench of the turbulence transport by E × B rotation shear.

  8. Nanocellulose Derivative/Silica Hybrid Core-Shell Chiral Stationary Phase: Preparation and Enantioseparation Performance.

    PubMed

    Zhang, Xiaoli; Wang, Litao; Dong, Shuqing; Zhang, Xia; Wu, Qi; Zhao, Liang; Shi, Yanping

    2016-01-01

    Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs) were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material. PMID:27153055

  9. Core-corona separation in the UrQMD hybrid model

    SciTech Connect

    Steinheimer, J.; Bleicher, M.

    2011-08-15

    We employ the UrQMD transport + hydrodynamics hybrid model to estimate the effects of a separation of the hot equilibrated core and the dilute corona created in high-energy heavy-ion collisions. It is shown that the fraction of the system that can be regarded as an equilibrated fireball changes over a wide range of energies. This has an impact, especially on strange particle abundances. We show that such a core corona separation allows for an improvement in the description of strange particle ratios and flow as a function of beam energy as well as strange particle yields as a function of centrality.

  10. Assembly of large metagenome data sets using a Convey HC-1 hybrid core computer (7th Annual SFAF Meeting, 2012)

    ScienceCinema

    Copeland, Alex [DOE JGI

    2013-02-11

    Alex Copeland on "Assembly of large metagenome data sets using a Convey HC-1 hybrid core computer" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  11. Prediction of core cancer genes using a hybrid of feature selection and machine learning methods.

    PubMed

    Liu, Y X; Zhang, N N; He, Y; Lun, L J

    2015-01-01

    Machine learning techniques are of great importance in the analysis of microarray expression data, and provide a systematic and promising way to predict core cancer genes. In this study, a hybrid strategy was introduced based on machine learning techniques to select a small set of informative genes, which will lead to improving classification accuracy. First feature filtering algorithms were applied to select a set of top-ranked genes, and then hierarchical clustering and collapsing dense clusters were used to select core cancer genes. Through empirical study, our approach is capable of selecting relatively few core cancer genes while making high-accuracy predictions. The biological significance of these genes was evaluated using systems biology analysis. Extensive functional pathway and network analyses have confirmed findings in previous studies and can bring new insights into common cancer mechanisms. PMID:26345818

  12. Fluorescent in situ hybridization in routinely processed bone marrow aspirate clot and core biopsy sections.

    PubMed Central

    Miranda, R. N.; Mark, H. F.; Medeiros, L. J.

    1994-01-01

    Fluorescent in situ hybridization (FISH) is a technique which complements conventional cytogenetic banding analysis by allowing the evaluation of cells in interphase as well as metaphase. This technique has been used to study air-dried peripheral blood and bone marrow aspirate smears. We have applied the FISH technique to study routinely processed sections of bone marrow aspirate clot and decalcified core biopsy specimens, fixed in either formalin or B5 and embedded in paraffin. We evaluated 28 specimens (8 aspirate clot and 20 core biopsy sections) for chromosome 8 copy number, studied previously by conventional cytogenetics, and found the following distribution: 15 with disomy, 11 with trisomy, and 2 with tetrasomy. Using a chromosome 8 alpha-satellite probe, we detected fluorescent hybridization signals in 18 of 28 specimens (64%); 6 of 8 (75%) aspirate clot sections, and 12 of 20 (60%) core biopsy sections. Ten of 13 (77%) B5-fixed and 8 of 15 (53%) formalin-fixed specimens had hybridizing signals. Specimen age was a significant factor; 10 of 11 (91%) specimens processed within the last 6 months showed signals, in contrast with 8 of 17 (47%) specimens older than 6 months. In the positive specimens, 200 cells were analyzed in areas where individual cells could be identified. In the disomic specimens, two signals per cell were seen in 34 to 66% of the cells. Rare cells (0-2%) with three signals were detected. In the trisomic specimens, three signals per cell were seen in 19 to 46% of the cells. In the tetrasomic specimens, four signals per cell were seen in 15 to 25% of the cells. We conclude that the FISH technique may be useful in the detection of numerical chromosomal abnormalities such as trisomy and tetrasomy 8 in routinely processed bone marrow aspirate clot and decalcified core biopsy sections. Images Figure 1 Figure 2 Figure 3 PMID:7992836

  13. A Novel Organophosphorus Hybrid with Excellent Thermal Stability: Core-Shell Structure, Hybridization Mechanism, and Application in Flame Retarding Semi-Aromatic Polyamide.

    PubMed

    Lin, Xue-Bao; Du, Shuang-Lan; Long, Jia-Wei; Chen, Li; Wang, Yu-Zhong

    2016-01-13

    An organophosphorous hybrid (BM@Al-PPi) with unique core-shell structure was prepared through hybridization reaction between boehmite (BM) as the inorganic substrate and phenylphosphinic acid (PPiA) as the organic modifier. Fourier transform infrared spectra (FTIR), solid state (31)P and (27)Al magic angle spinning nuclear magnetic resonance, X-ray diffraction, and element analysis were used to investigate the chemical structure of the hybrids, where the microrod-like core was confirmed as Al-PPi aggregates generated from the reaction between BM and PPiA, and those irregular nanoparticles in the shell belonged to residual BM. Compared with the traditional dissolution-precipitation process, a novel analogous suspension reaction mode was proposed to explain the hybridization process and the resulting product. Scanning electronic microscopy further proved the core-shell structure of the hybrids. BM exhibited much higher initial decomposition temperature than that of Al-PPi; therefore, the hybrid showed better thermal stability than Al-PPi, and it met the processing temperature of semi-aromatic polyamide (HTN, for instance) as an additive-type flame retardant. Limiting oxygen index and cone calorimetric analysis suggested the excellent flame-retardant performance and smoke suppressing activity by adding the resulting hybrid into HTN. PMID:26709944

  14. Anisotropic pressure in the quark core of a strongly magnetized hybrid star

    NASA Astrophysics Data System (ADS)

    Isayev, A. A.

    2015-05-01

    The impact of a strong magnetic field, varying with the total baryon number density, on thermodynamic properties of strange quark matter (SQM) in the core of a magnetized hybrid star is considered at zero temperature within the framework of the Massachusetts Institute of Technology (MIT) bag model. It is clarified that the central magnetic field strength is bound from above by the value at which the derivative of the longitudinal pressure with respect to the baryon number density vanishes first somewhere in the quark core under varying the central field. Above this upper bound, the instability along the magnetic field is developed in magnetized SQM. The total energy density, longitudinal and transverse pressures are found as functions of the total baryon number density.

  15. Synthesis of core-corona polymer hybrids with a raspberry-like structure by the heterocoagulated pyridinium reaction.

    PubMed

    Wang, Junyou; Yang, Xinlin

    2008-04-01

    A core-corona polymer hybrid with a raspberry-like structure was synthesized via the heterocoagulated pyridium reaction between the pyridyl group of poly(ethylene glycol dimethacrylate-co-methacrylic acid)@poly(ethylene glycol dimethacrylate-co- vinylpyridine) (poly(EGDMA-co-MAA)@poly(EGDMA-co-VPy)) core-shell small microspheres and the chloromethyl group of poly(divinylbenzene-co-chloromethyl styrene) (poly(DVB-co-CMSt)) microspheres, in which poly(EGDMA-co-MAA)@poly(EGDMA-co-VPy) acted as the corona and poly(DVB-co-CMSt) behaved as the core. The control coverage of the corona particles on the surfaces of core microspheres for the polymer hybrid was studied in detail through the adjustment of the mass ratio between the core and corona particles. The effects of the pH and solvents on the stability of the raspberry-like core-corona hybrids were investigated. The water static angle on the surface of polycarbonate (PC) film was studied using a contact angle system. The polymer particles and the resultant heterocoagulated raspberry-like hybrids were characterized with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nature of the heterocoagulation between the core microspheres and corona particles was identified as the covalent pyridium reaction with Fourier transform infrared (FT-IR) spectroscopy. PMID:18288875

  16. Identifying core, exciting, and hybrid attributes in fans' assessments of major (World Cup) spectator sports events.

    PubMed

    Gau, Li-Shiue

    2013-12-01

    This paper adopts a methodology of asymmetrical analyses to investigate the relevant importance of spectator sport attributes in terms of their non-linear associations with the benefits that fans experience while watching sports. Questionnaires tapping 16 attributes (e.g., teamwork, sportsmanship, level of competition) and 16 benefits (e.g., good mood, exciting experience, support for my favorite team) were distributed to a sample of fans at the outdoor broadcast of the 2010 World Cup final game at the National Stadium in Kaohsiung, Taiwan. 427 participants rated the importance and benefit of each attribute experienced from watching the game. Attributes were categorized as core, exciting, or hybrid attributes. The star player was the core attribute; rivalry, popularity, and coach were the exciting attributes; and the other 12 attributes were hybrid. Two-dimensional space analyses showed that attributes "sportsmanship, teamwork, and supporting a team" were both explicitly and implicitly important attributes. The methodology of asymmetrical analyses can help managers prioritize the focus of attributes and allocate resources effectively. PMID:24693812

  17. Core-shell nanostructured hybrid composites for volatile organic compound detection.

    PubMed

    Tung, Tran Thanh; Losic, Dusan; Park, Seung Jun; Feller, Jean-Francois; Kim, TaeYoung

    2015-01-01

    We report a high-performance chemiresistive sensor for detection of volatile organic compound (VOC) vapors based on core-shell hybridized nanostructures of Fe3O4 magnetic nanoparticles (MNPs) and poly(3,4-ethylenedioxythiophene) (PEDOT)-conducting polymers. The MNPs were prepared using microwave-assisted synthesis in the presence of polymerized ionic liquids (PILs), which were used as a linker to couple the MNP and PEDOT. The resulting PEDOT-PIL-modified Fe3O4 hybrids were then explored as a sensing channel material for a chemiresistive sensor to detect VOC vapors. The PEDOT-PIL-modified Fe3O4 sensor exhibited a tunable response, with high sensitivity (down to a concentration of 1 ppm) and low noise level, to VOCs; these VOCs include acetone vapor, which is present in the exhaled breath of potential lung cancer patients. The present sensor, based on the hybrid nanostructured sensing materials, exhibited a 38.8% higher sensitivity and an 11% lower noise level than its PEDOT-PIL-only counterpart. This approach of embedding MNPs in conducting polymers could lead to the development of new electronic noses, which have significant potential for the use in the early diagnosis of lung cancer via the detection of VOC biomarkers. PMID:26357471

  18. Core-shell nanostructured hybrid composites for volatile organic compound detection

    PubMed Central

    Tung, Tran Thanh; Losic, Dusan; Park, Seung Jun; Feller, Jean-Francois; Kim, TaeYoung

    2015-01-01

    We report a high-performance chemiresistive sensor for detection of volatile organic compound (VOC) vapors based on core-shell hybridized nanostructures of Fe3O4 magnetic nanoparticles (MNPs) and poly(3,4-ethylenedioxythiophene) (PEDOT)-conducting polymers. The MNPs were prepared using microwave-assisted synthesis in the presence of polymerized ionic liquids (PILs), which were used as a linker to couple the MNP and PEDOT. The resulting PEDOT–PIL-modified Fe3O4 hybrids were then explored as a sensing channel material for a chemiresistive sensor to detect VOC vapors. The PEDOT–PIL-modified Fe3O4 sensor exhibited a tunable response, with high sensitivity (down to a concentration of 1 ppm) and low noise level, to VOCs; these VOCs include acetone vapor, which is present in the exhaled breath of potential lung cancer patients. The present sensor, based on the hybrid nanostructured sensing materials, exhibited a 38.8% higher sensitivity and an 11% lower noise level than its PEDOT–PIL-only counterpart. This approach of embedding MNPs in conducting polymers could lead to the development of new electronic noses, which have significant potential for the use in the early diagnosis of lung cancer via the detection of VOC biomarkers. PMID:26357471

  19. Core-shell nanophosphor architecture: toward efficient energy transport in inorganic/organic hybrid solar cells.

    PubMed

    Li, Qinghua; Yuan, Yongbiao; Chen, Zihan; Jin, Xiao; Wei, Tai-huei; Li, Yue; Qin, Yuancheng; Sun, Weifu

    2014-08-13

    In this work, a core-shell nanostructure of samarium phosphates encapsulated into a Eu(3+)-doped silica shell has been successfully fabricated, which has been confirmed by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution TEM. Moreover, we report the energy transfer process from the Sm(3+) to emitters Eu(3+) that widens the light absorption range of the hybrid solar cells (HSCs) and the strong enhancement of the electron-transport of TiO2/poly(3-hexylthiophene) (P3HT) bulk heterojunction (BHJ) HSCs by introducing the unique core-shell nanoarchitecture. Furthermore, by applying femtosecond transient absorption spectroscopy, we successfully obtain the electron transport lifetimes of BHJ systems with or without incorporating the core-shell nanophosphors (NPs). Concrete evidence has been provided that the doping of core-shell NPs improves the efficiency of electron transfers from donor to acceptor, but the hole transport almost remains unchanged. In particular, the hot electron transfer lifetime was shortened from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO2 acceptor. Consequently, a notable power conversion efficiency of 3.30% for SmPO4@Eu(3+):SiO2 blended TiO2/P3HT HSCs is achieved at 5 wt % as compared to 1.98% of pure TiO2/P3HT HSCs. This work indicates that the core-shell NPs can efficiently broaden the absorption region, facilitate electron-transport of BHJ, and enhance photovoltaic performance of inorganic/organic HSCs. PMID:24967836

  20. Production Level CFD Code Acceleration for Hybrid Many-Core Architectures

    NASA Technical Reports Server (NTRS)

    Duffy, Austen C.; Hammond, Dana P.; Nielsen, Eric J.

    2012-01-01

    In this work, a novel graphics processing unit (GPU) distributed sharing model for hybrid many-core architectures is introduced and employed in the acceleration of a production-level computational fluid dynamics (CFD) code. The latest generation graphics hardware allows multiple processor cores to simultaneously share a single GPU through concurrent kernel execution. This feature has allowed the NASA FUN3D code to be accelerated in parallel with up to four processor cores sharing a single GPU. For codes to scale and fully use resources on these and the next generation machines, codes will need to employ some type of GPU sharing model, as presented in this work. Findings include the effects of GPU sharing on overall performance. A discussion of the inherent challenges that parallel unstructured CFD codes face in accelerator-based computing environments is included, with considerations for future generation architectures. This work was completed by the author in August 2010, and reflects the analysis and results of the time.

  1. Tokamak Fusion Core Experiment: design studies based on superconducting and hybrid toroidal field coils. Design overview

    SciTech Connect

    Flanagan, C.A.

    1984-10-01

    This document is a design overview that describes the scoping studies and preconceptual design effort performed in FY 1983 on the Tokamak Fusion Core Experiment (TFCX) class of device. These studies focussed on devices with all-superconducting toroidal field (TF) coils and on devices with superconducting TF coils supplemented with copper TF coil inserts located in the bore of the TF coils in the shield region. Each class of device is designed to satisfy the mission of ignition and long pulse equilibrium burn. Typical design parameters are: major radius = 3.75 m, minor radius = 1.0 m, field on axis = 4.5 T, plasma current = 7.0 MA. These designs relay on lower hybrid (LHRH) current rampup and heating to ignition using ion cyclotron range of frequency (ICRF). A pumped limiter has been assumed for impurity control. The present document is a design overview; a more detailed design description is contained in a companion document.

  2. Nanoparticle-cored dendrimers: functional hybrid nanocomposites as a new platform for drug delivery systems

    NASA Astrophysics Data System (ADS)

    Brunetti, V.; Bouchet, L. M.; Strumia, M. C.

    2015-02-01

    Nanoparticle-cored dendrimers (NCDs) are now offering themselves as versatile carriers because of their colloidal stability, tunable membrane properties and ability to encapsulate or integrate a broad range of drugs and molecules. This kind of hybrid nanocomposite aims to combine the advantages of stimuli-responsive dendritic coatings, in order to regulate the drug release behaviour under different conditions and improve the biocompatibility and in vivo half-time circulation of the inorganic nanoparticles. Size, surface chemistry and shape are key nanocarrier properties to evaluate. Here, we have reviewed the most recent advances of NCDs in drug delivery systems, compared their behaviour with non-dendritic stabilized nanoparticles and highlighted their challenges and promising applications in the future.

  3. Hybridization of a flexible cyclooctatetraene core and rigid aceneimide wings for multiluminescent flapping π systems.

    PubMed

    Yuan, Chunxue; Saito, Shohei; Camacho, Cristopher; Kowalczyk, Tim; Irle, Stephan; Yamaguchi, Shigehiro

    2014-02-17

    The hybridization of flexible and rigid π-conjugated frameworks is a potent concept for producing new functional materials. In this article, a series of multifluorescent flapping π systems that combine a flexible cyclooctatetraene (COT) core and rigid aceneimide wings with various π-conjugation lengths has been designed and synthesized, and their structure/properties relationships have been investigated. Whereas these molecules have a V-shaped bent conformation in the ground state, the bent structure changes to a planar conformation in the lowest excited singlet (S1 ) state irrespective of the lengths of the aceneimide wings. However, the fluorescence behavior in solution is distinct between the naphthaleneimide system and the anthraceneimide system. The former has a nonemissive S1 state owing to the significant contribution of the antiaromatic character of the planar COT frontier molecular orbitals, thereby resulting in complete fluorescence quenching in solution. In contrast, the latter anthraceneimide system shows an intense emission, which is ascribed to the planar but distorted S1 state that shows the allowed transition between the π-molecular orbitals delocalized over the COT core and the acene wings. The other characteristic of these π systems is the significantly redshifted fluorescence in the crystalline state relative to their monomer fluorescence. The relationship between the packing structures and the fluorescence properties was investigated by preparing a series of hybrid π systems with different sizes of substituents on the imide moieties, which revealed the effect of the twofold π-stacked structure of the V-shaped molecules on the large bathochromic shift in emission. PMID:24458337

  4. Dual Transient Bleaching of Au/PbS Hybrid Core/Shell Nanoparticles.

    PubMed

    Kobayashi, Yoichi; Nonoguchi, Yoshiyuki; Wang, Li; Kawai, Tsuyoshi; Tamai, Naoto

    2012-05-01

    We examined the optical response of hybrid Au/PbS core/shell nanoparticles (NPs) using transient absorption spectroscopy. Finite-difference time-domain (FDTD) calculations and transient absorption measurements show that Au/PbS NPs have unique two extinction peaks: the peak at the longer wavelength (∼700 nm) is originated from the plasmon, and that at the shorter wavelength (550 nm) is from the local maximum of the refractive index of PbS. The transient absorption dynamics of Au/PbS NPs excited at 400 nm have clear oscillation behavior, which is assigned to the breathing mode of whole particle. We observed a weak excitation-wavelength dependence of the plasmon band. The time constant of electron-phonon coupling of Au/PbS NPs was obtained by changing the excitation intensity. We show that spectral properties of Au/PbS NPs are strongly altered by the hybrid formations, while their dynamics differ only minimally compared with those of Au NPs. PMID:26288045

  5. NBI fast ion confinement in the helical core of MAST hybrid-like plasmas

    NASA Astrophysics Data System (ADS)

    Pfefferlé, D.; Graves, J. P.; Cooper, W. A.; Misev, C.; Chapman, I. T.; Turnyanskiy, M.; Sangaroon, S.

    2014-06-01

    Energetic ions are found to be transported strongly from the core of MAST hybrid-like plasmas during long-lived mode (LLM) magnetohydrodynamic activity. The resulting impact on the neutral beam ion deposition and concurrent current drive is modelled using the guiding-centre approximation in the internal kinked magnetic topology. General coordinate guiding-centre equations are extended for this purpose. It is found that the kinked core spirals around the position of strongest ionization, which remains geometrically centred, so that a large fraction of the population is deposited in the high shear external region where the plasma is almost axisymmetric. Those particles ionized in the low shear region exhibit exotic drift motion due to the strongly non-axisymmetric equilibrium, periodically passing near the magnetic axis and then reflected by the boundary of the kinked equilibrium, which in this respect acts as a confining pinch. Broad agreement is found against experimental measurement of fast ion particle confinement degradation as the MAST LLM amplitude varies.

  6. Formation mechanism of monodispersed spherical core-shell ceria/polymer hybrid nanoparticles

    SciTech Connect

    Izu, Noriya; Uchida, Toshio; Matsubara, Ichiro; Itoh, Toshio; Shin, Woosuck; Nishibori, Maiko

    2011-08-15

    Graphical abstract: The formation mechanism for core-shell nanoparticles is considered to be as follows: nucleation and particle growth occur simultaneously (left square); very slow particle growth occurs (middle square). Highlights: {yields} The size of the resultant nanoparticles was strongly and complicatedly dependent on the set temperature used during reflux heating and the PVP molecular weight. {yields} The size of the nanoparticles increased by a 2-step process as the reflux heating time increased. {yields} The IR spectral changes with increasing reflux time indicated the increase in the number of cross-linked polymers in the shell. -- Abstract: Very unique core-shell ceria (cerium oxide)/polymer hybrid nanoparticles that have monodispersed spherical structures and are easily dispersed in water or alcohol without the need for a dispersant were reported recently. The formation mechanism of the unique nanoparticles, however, was not clear. In order to clarify the formation mechanism, these nanoparticles were prepared using a polyol method (reflux heating) under varied conditions of temperature, time, and concentration and molecular weight of added polymer (poly(vinylpyrrolidone)). The size of the resultant nanoparticles was strongly and complicatedly dependent on the set temperature used during reflux heating and the poly(vinylpyrrolidone) molecular weight. Furthermore, the size of the nanoparticles increased by a 2-step process as the reflux heating time increased. The IR spectral changes with increasing reflux time indicated the increase in the number of cross-linked polymers in the shell. From these results, the formation mechanism was discussed and proposed.

  7. Development of Yangbajing air shower core detector for a new EAS hybrid experiment

    NASA Astrophysics Data System (ADS)

    Liu, Jin-Sheng; Huang, Jing; Chen, Ding; Zhang, Ying; Zhai, Liu-Ming; Chen, Xu; Hu, Xiao-Bin; Lin, Yu-Hui; Zhang, Xue-Yao; Feng, Cun-Feng; Jia, Huan-Yu; Zhou, Xun-Xiu; Danzengluobu; Chen, Tian-Lu; Li, Hai-Jin; Liu, Mao-Yuan; Yuan, Ai-Fang

    2015-08-01

    Aiming at the observation of cosmic-ray chemical composition in the “knee” energy region, we have been developing a new type of air-shower core detector (YAC, Yangbajing Air shower Core detector array) to be set up at Yangbajing (90.522° E, 30.102° N, 4300 m above sea level, atmospheric depth: 606 g/m2) in Tibet, China. YAC works together with the Tibet air-shower array (Tibet-III) and an underground water Cherenkov muon detector array (MD) as a hybrid experiment. Each YAC detector unit consists of lead plates of 3.5 cm thickness and a scintillation counter which detects the burst size induced by high energy particles in the air-shower cores. The burst size can be measured from 1 MIP (Minimum Ionization Particle) to 106 MIPs. The first phase of this experiment, named “YAC- I”, consists of 16 YAC detectors each with a size of 40 cm×50 cm and distributed in a grid with an effective area of 10 m2. YAC- I is used to check hadronic interaction models. The second phase of the experiment, called “YAC- II”, consists of 124 YAC detectors with coverage of about 500 m2. The inner 100 detectors of 80 cm×50 cm each are deployed in a 10×10 matrix with a 1.9 m separation; the outer 24 detectors of 100 cm×50 cm each are distributed around these to reject non-core events whose shower cores are far from the YAC- II array. YAC- II is used to study the primary cosmic-ray composition, in particular, to obtain the energy spectra of protons, helium and iron nuclei between 5×1013 eV and 1016 eV, covering the “knee” and also connected with direct observations at energies around 100 TeV. We present the design and performance of YAC- II in this paper. Supported by grants from the National Natural Science Foundation of China (11078002, 11275212, 11165013), the Chinese Academy of Sciences (H9291450S3, Y4293211S5) and the Knowledge Innovation Fund of Institute of High Energy Physics (IHEP), China (H95451D0U2, H8515530U1)

  8. Enhanced performance of core-shell structured polyaniline at helical carbon nanotube hybrids for ammonia gas sensor

    SciTech Connect

    Tian, Xin; Wang, Qiang; Chen, Xiangnan; Yang, Weiqing; Xu, Xiaoling E-mail: bihan-2001@163.com; Jiang, Man; Zhou, Zuowan E-mail: bihan-2001@163.com; Wu, Zuquan

    2014-11-17

    A core-shell structured hybrid of polyaniline at helical carbon nanotubes was synthesized using in situ polymerization, which the helical carbon nanotubes were uniformly surrounded by a layer of polyaniline nanorods array. More interestingly, repeatable responses were experimentally observed that the sensitivity to ammonia gas of the as-prepared helical shaped core-shell hybrid displays an enhancement of more than two times compared to those of only polyaniline or helical carbon nanotubes sensors because of the peculiar structures with high surface area. This kind of hybrid comprising nanorod arrays of conductive polymers covering carbon nanotubes and related structures provide a potential in sensors of trace gas detection for environmental monitoring and safety forecasting.

  9. RTA-treated carbon fiber/copper core/shell hybrid for thermally conductive composites.

    PubMed

    Yu, Seunggun; Park, Bo-In; Park, Cheolmin; Hong, Soon Man; Han, Tae Hee; Koo, Chong Min

    2014-05-28

    In this paper, we demonstrate a facile route to produce epoxy/carbon fiber composites providing continuous heat conduction pathway of Cu with a high degree of crystal perfection via electroplating, followed by rapid thermal annealing (RTA) treatment and compression molding. Copper shells on carbon fibers were coated through electroplating method and post-treated via RTA technique to reduce the degree of imperfection in the Cu crystal. The epoxy/Cu-plated carbon fiber composites with Cu shell of 12.0 vol % prepared via simple compression molding, revealed 18 times larger thermal conductivity (47.2 W m(-1) K(-1)) in parallel direction and 6 times larger thermal conductivity (3.9 W m(-1) K(-1)) in perpendicular direction than epoxy/carbon fiber composite. Our novel composites with RTA-treated carbon fiber/Cu core/shell hybrid showed heat conduction behavior of an excellent polymeric composite thermal conductor with continuous heat conduction pathway, comparable to theoretical values obtained from Hatta and Taya model. PMID:24758290

  10. Preparation of Core-Shell Hybrid Compounds by Atomic Transfer Radical Polymerization and Its Application to Plastic Lens of Headlamp.

    PubMed

    Noh, Seung-Man; Ahn, Jae-Beum; Choi, Ki-Hyun; Park, Seung-Kyu

    2015-09-01

    Nano silica ball (NSB) core polymethylmethacrylate (PMMA) shell hybrid nanocomposites were synthesized by atomic transfer radical polymerization (ATRP) method for the application to the clearcoat to enhance scratch resistance. The characteristics of the synthesized inorganic/organic hybrid material were examined by scanning electron microscope (SEM), particle size analysis, Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis-differential scanning calorimetry (TGA-DSC). The scratch resistance and light transmittance of the clearcoat were measured by a nano-scratch tester and UV-visible spectroscopy, respectively. The average particle size of the NSB-PMMA hybrid compounds was 30 nm with narrow size distribution. Even 0.1 wt% loading of NSB-PMMA in the clearcoat dramatically enhanced the scratch resistance, about 40% increase in the force of the first fracture, while slightly reduced the light transmittance, about 5% only. PMID:26716303

  11. Light-weight sandwich panel honeycomb core with hybrid carbon-glass fiber composite skin for electric vehicle application

    NASA Astrophysics Data System (ADS)

    Cahyono, Sukmaji Indro; Widodo, Angit; Anwar, Miftahul; Diharjo, Kuncoro; Triyono, Teguh; Hapid, A.; Kaleg, S.

    2016-03-01

    The carbon fiber reinforced plastic (CFRP) composite is relative high cost material in current manufacturing process of electric vehicle body structure. Sandwich panels consisting polypropylene (PP) honeycomb core with hybrid carbon-glass fiber composite skin were investigated. The aim of present paper was evaluate the flexural properties and bending rigidity of various volume fraction carbon-glass fiber composite skins with the honeycomb core. The flexural properties and cost of panels were compared to the reported values of solid hybrid Carbon/Glass FRP used for the frame body structure of electric vehicle. The finite element model of represented sandwich panel was established to characterize the flexural properties of material using homogenization technique. Finally, simplified model was employed to crashworthiness analysis for engine hood of the body electric vehicle structure. The good cost-electiveness of honeycomb core with hybrid carbon-glass fiber skin has the potential to be used as a light-weight alternative material in body electric vehicle fabricated.

  12. Efficient Graph Based Assembly of Short-Read Sequences on Hybrid Core Architecture

    SciTech Connect

    Sczyrba, Alex; Pratap, Abhishek; Canon, Shane; Han, James; Copeland, Alex; Wang, Zhong; Brewer, Tony; Soper, David; D'Jamoos, Mike; Collins, Kirby; Vacek, George

    2011-03-22

    Advanced architectures can deliver dramatically increased throughput for genomics and proteomics applications, reducing time-to-completion in some cases from days to minutes. One such architecture, hybrid-core computing, marries a traditional x86 environment with a reconfigurable coprocessor, based on field programmable gate array (FPGA) technology. In addition to higher throughput, increased performance can fundamentally improve research quality by allowing more accurate, previously impractical approaches. We will discuss the approach used by Convey?s de Bruijn graph constructor for short-read, de-novo assembly. Bioinformatics applications that have random access patterns to large memory spaces, such as graph-based algorithms, experience memory performance limitations on cache-based x86 servers. Convey?s highly parallel memory subsystem allows application-specific logic to simultaneously access 8192 individual words in memory, significantly increasing effective memory bandwidth over cache-based memory systems. Many algorithms, such as Velvet and other de Bruijn graph based, short-read, de-novo assemblers, can greatly benefit from this type of memory architecture. Furthermore, small data type operations (four nucleotides can be represented in two bits) make more efficient use of logic gates than the data types dictated by conventional programming models.JGI is comparing the performance of Convey?s graph constructor and Velvet on both synthetic and real data. We will present preliminary results on memory usage and run time metrics for various data sets with different sizes, from small microbial and fungal genomes to very large cow rumen metagenome. For genomes with references we will also present assembly quality comparisons between the two assemblers.

  13. A core-shell structured inorganic-organic hybrid nanocomposite for Hg(II) sensing and removal.

    PubMed

    Jiqu, Han; Qixia, Yang

    2015-10-01

    In the present paper, a core-shell structured inorganic-organic hybrid nanocomposite for Hg(II) sensing and removal was designed and fabricated, where the core was composed of superparamagnetic Fe3O4 and the shell consisted of molecular silica sieve MCM-41. A rhodamine derived probe was grafted onto the backbone of MCM-41 through a silane coupling reagent to control its loading content. This probe functionalized core-shell structure was confirmed and characterized by XRD analysis, electron microscopy images, IR spectra, thermogravimetry and N2 adsorption/desorption isotherms. It was found that the emission of this composite increased with increasing Hg(II) concentrations but was immune to other metal ions, showing good selectivity and high sensitivity towards Hg(II) ions. A linear Stern-Volmer curve was observed with short response time. In addition, this composite possessed good Hg(II)-removing and recycling performance. PMID:25978016

  14. Engineering of high performance supercapacitor electrode based on Fe-Ni/Fe2O3-NiO core/shell hybrid nanostructures

    NASA Astrophysics Data System (ADS)

    Singh, Ashutosh K.; Mandal, Kalyan

    2015-03-01

    The present work reports on fabrication and supercapacitor applications of a core/shell Fe-Ni/Fe2O3-NiO hybrid nanostructures (HNs) electrode. The core/shell Fe-Ni/Fe2O3-NiO hybrid nanostructures have been fabricated through a two step method (nanowire fabrication and their controlled oxidation). The 1D hybrid nanostructure consists of highly porous shell layer (redox active materials NiO and Fe2O3) and the conductive core (FeNi nanowire). Thus, the highly porous shell layer allows facile electrolyte diffusion as well as faster redox reaction kinetics; whereas the conductive FeNi nanowire core provides the proficient express way for electrons to travel to the current collector, which helps in the superior electrochemical performance. The core/shell Fe-Ni/Fe2O3-NiO hybrid nanostructures electrode based supercapacitor shows very good electrochemical performances in terms of high specific capacitance nearly 1415 F g-1 at a current density of 2.5 A g-1, excellent cycling stability and rate capability. The high quality electrochemical performance of core/shell hybrid nanostructures electrode shows its potential as an alternative electrode for forthcoming supercapacitor devices.

  15. Engineering of high performance supercapacitor electrode based on Fe-Ni/Fe{sub 2}O{sub 3}-NiO core/shell hybrid nanostructures

    SciTech Connect

    Singh, Ashutosh K. E-mail: aksingh@bose.res.in; Mandal, Kalyan

    2015-03-14

    The present work reports on fabrication and supercapacitor applications of a core/shell Fe-Ni/Fe{sub 2}O{sub 3}-NiO hybrid nanostructures (HNs) electrode. The core/shell Fe-Ni/Fe{sub 2}O{sub 3}-NiO hybrid nanostructures have been fabricated through a two step method (nanowire fabrication and their controlled oxidation). The 1D hybrid nanostructure consists of highly porous shell layer (redox active materials NiO and Fe{sub 2}O{sub 3}) and the conductive core (FeNi nanowire). Thus, the highly porous shell layer allows facile electrolyte diffusion as well as faster redox reaction kinetics; whereas the conductive FeNi nanowire core provides the proficient express way for electrons to travel to the current collector, which helps in the superior electrochemical performance. The core/shell Fe-Ni/Fe{sub 2}O{sub 3}-NiO hybrid nanostructures electrode based supercapacitor shows very good electrochemical performances in terms of high specific capacitance nearly 1415 F g{sup −1} at a current density of 2.5 A g{sup −1}, excellent cycling stability and rate capability. The high quality electrochemical performance of core/shell hybrid nanostructures electrode shows its potential as an alternative electrode for forthcoming supercapacitor devices.

  16. Constructing Hierarchically Hollow Core-Shell MnO2 /C Hybrid Spheres for High-Performance Lithium Storage.

    PubMed

    Wang, Gang; Sun, Yuhan; Li, Debao; Wei, Wei; Feng, Xinliang; Müllen, Klaus

    2016-08-01

    Hierarchical MnO2 /C hybrid spheres (MCS@MnO2 ), consisting of numerous hollow core-shell MnO2 @C nanospheres, are developed via a facile deposition process. The well-defined inner voids and robust carbon framework endow MCS@MnO2 with excellent mechanical stability, efficient utilization of MnO2 , and enhanced reaction kinetics for Li-ion batteries, therefore leading to large specific capacities, superior rate capability, and long-term cycling stability. PMID:27275631

  17. High Color-Rendering-index Hybrid White LEDs Employing CdSe/ZnS Core/Shell Quantum Dots.

    PubMed

    Chang, Yajing; Sun, Dapeng; Zhang, Zhongping; Zhang, Yugang; Yao, Xudong; Jiang, Danlu; Yu, Yalan; Mi, Longfei; Chen, Lei; Zhong, Honghai; Jiang, Yang

    2016-01-01

    Hybrid white LEDs were constructed by leveraging a combination of CdSe/ZnS core/shell QDs and YAG: Ce³⁺ phosphors. The CdSe/ZnS core/shell QDs were synthesized by a two-step process in which CdSe QDs were first prepared via a hot-injection method, followed by ZnS coating through a facile single-molecular precursor approach. The resultant red-emitting CdSe/ZnS QDs showed decent fluorescent quantum yielding (36%). The resultant hybrid white LEDs--that based on CdSe/ZnS QDs and solid-state-reaction-processed YAG: Ce³⁺ phosphors--showed good luminescence properties, including bright warm light, a high color rendering index of 91.3, a low color temperature of 4965 K and a luminous efficiency of 44.22 lm/W. Moreover, increased luminous intensity has been observed in the presence of increased forward current without luminescence saturation, promising an ideal approach to construct warm-white LEDs with excellent color rendering properties. PMID:27398506

  18. Ag@AgI, core@shell structure in agarose matrix as hybrid: synthesis, characterization, and antimicrobial activity.

    PubMed

    Ghosh, Somnath; Saraswathi, A; Indi, S S; Hoti, S L; Vasan, H N

    2012-06-01

    A novel in situ core@shell structure consisting of nanoparticles of Ag (Ag Nps) and AgI in agarose matrix (Ag@AgI/agarose) has been synthesized as a hybrid, in order to have an efficient antibacterial agent for repetitive usage with no toxicity. The synthesized core@shell structure is very well characterized by XRD, UV-visible, photoluminescence, and TEM. A detailed antibacterial studies including repetitive cycles are carried out on Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria in saline water, both in dark and on exposure to visible light. The hybrid could be recycled for the antibacterial activity and is nontoxic toward human cervical cancer cells (HeLa cells). The water insoluble Ag@AgI in agarose matrix forms a good coating on quartz, having good mechanical strength. EPR and TEM studies are carried out on the Ag@AgI/agarose and the bacteria, respectively, to elucidate a possible mechanism for killing of the bacteria. PMID:22582868

  19. Atomically smooth hybrid crystalline-core glass-clad fibers for low-loss broadband wave guiding.

    PubMed

    Lai, Chien-Chih; Lo, Chia-Yao; Nguyen, Duc Huy; Huang, Jian-Zhi; Tsai, Wan-Shao; Ma, Yuan-Ron

    2016-09-01

    We demonstrate direct evidence for the first realization of atomically smooth sapphire crystalline fiber cores with a surface variation of only ~1.9 Å. The hybrid glass-clad crystalline cores were grown by a laser-based fiber drawing technique. Because of the improvement in crystal fiber quality, we were able, for the first time, to comprehensively and quantitatively elucidate the correlation between fiber nanostructure and optical loss. We also experimentally demonstrated that high-temperature treatment has a significant impact on defect relaxation and promotes excellent crystallinity, and hence enables low-loss optical wave guiding. The experimentally measured propagation losses in the order of 0.01-0.1 dB/cm are the lowest ever reported among conventional Ti:sapphire channel waveguides and ultrafast-laser-inscribed waveguides, and agree well with the theory. Through experiments and numerical calculation, we have demonstrated that low threshold and high efficiency of Ti:sapphire crystal fiber lasers are possible with the atomic-level roughness, low-loss propagation, and high crystallinity of the Ti:sapphire crystalline core. PMID:27607618

  20. Hybrid core/shell microparticles and their use for understanding biological processes.

    PubMed

    Bachhuka, Akash; Christo, Susan N; Cavallaro, Alex; Diener, Kerrilyn R; Mierczynska, Agnieszka; Smith, Louise E; Marian, Romeo; Manavis, Jim; Hayball, John D; Vasilev, Krasimir

    2015-11-01

    Hybrid micro and nanoparticles have become a topic of intense research in recent years. This is due to the special properties of these materials that open new avenues in advanced applications. Herein, we report a novel method for the generation of hybrid particles utilising plasma polymerization. Poly (methyl methacrylate) (PMMA) beads were first coated with a thin allylamine based plasma polymer layer. Gold nanoparticles of engineered size and surface structure were then attached in a controlled manner to the plasma polymer coated beads. To generate uniform chemistry on the outermost surface and to preserve the nanotopography, we deposited a 5-10 nm thin layer of Acpp. We demonstrated that these particles can be utilized in in vivo models to interrogate important biological phenomena. Specifically, we used them in mice to study the inflammatory and foreign body responses to surface nanotopography. The data strongly indicates that surface nanotopography and chemistry can modulate collagen production and the number of adhering immune cells. The method for generating hybrid particles reported here is solvent free and can open new opportunities in fields such as tissue engineering, drug delivery, biosensors, and regenerative medicine. PMID:26149416

  1. Magnetic response of hybrid ferromagnetic and antiferromagnetic core-shell nanostructures

    NASA Astrophysics Data System (ADS)

    Khan, U.; Li, W. J.; Adeela, N.; Irfan, M.; Javed, K.; Wan, C. H.; Riaz, S.; Han, X. F.

    2016-03-01

    The synthesis of FeTiO3-Ni(Ni80Fe20) core-shell nanostructures by a two-step method (sol-gel and DC electrodeposition) has been demonstrated. XRD analysis confirms the rhombohedral crystal structure of FeTiO3(FTO) with space group R3&cmb.macr;. Transmission electron microscopy clearly depicts better morphology of nanostructures with shell thicknesses of ~25 nm. Room temperature magnetic measurements showed significant enhancement of magnetic anisotropy for the permalloy (Ni80Fe20)-FTO over Ni-FTO core-shell nanostructures. Low temperature magnetic measurements of permalloy-FeTiO3 core-shell structure indicated a strong exchange bias mechanism with magnetic coercivity below the antiferromagnetic Neel temperature (TN = 59 K). The exchange bias is attributed to the alignment of magnetic moments in the antiferromagnetic material at low temperature. Our scheme opens a path towards optimum automotive systems and wireless communications wherein broader bandwidths and smaller sizes are required.The synthesis of FeTiO3-Ni(Ni80Fe20) core-shell nanostructures by a two-step method (sol-gel and DC electrodeposition) has been demonstrated. XRD analysis confirms the rhombohedral crystal structure of FeTiO3(FTO) with space group R3&cmb.macr;. Transmission electron microscopy clearly depicts better morphology of nanostructures with shell thicknesses of ~25 nm. Room temperature magnetic measurements showed significant enhancement of magnetic anisotropy for the permalloy (Ni80Fe20)-FTO over Ni-FTO core-shell nanostructures. Low temperature magnetic measurements of permalloy-FeTiO3 core-shell structure indicated a strong exchange bias mechanism with magnetic coercivity below the antiferromagnetic Neel temperature (TN = 59 K). The exchange bias is attributed to the alignment of magnetic moments in the antiferromagnetic material at low temperature. Our scheme opens a path towards optimum automotive systems and wireless communications wherein broader bandwidths and smaller sizes are

  2. Negative differential resistance in GeSi core-shell transport junctions: the role of local sp(2) hybridization.

    PubMed

    Liu, Nuo; Zhang, Lei; Chen, Xiaobin; Kong, Xianghua; Zheng, Xiaohong; Guo, Hong

    2016-09-21

    We report a theoretical investigation of nonlinear quantum transport properties of Au/GeSi/Au junctions. For GeSi semiconducting core-shell structures brought into contact with Au electrodes, a very unusual behavior is that the tunneling transport is on-resonance right at equilibrium. This resonance is not due to the alignment of a quantum level in GeSi to the electrochemical potential of Au, but due to the alignment of very sharp DOS features - hot spots, localized at the two Au/GeSi interfaces of the device. An applied bias voltage shifts the hot spots relative to each other which gives rise to substantial negative differential resistance (NDR). The hot spots localized at the two interfaces were found to be due to the unbonded pz orbital of a sp(2) hybridized interface Si atom which is surrounded by three non-sp(2) hybridized neighbors. The mechanism of inducing hot spots and NDR by a local structure unit is not limited to the GeSi. The results suggest an interesting scheme for constructing NDR devices by orbital manipulation, to be more explicit, for example, by designing local structural units having unbonded orbitals at the interfaces between electrodes and the central region of the transport junction. PMID:27546305

  3. Two-Dimensional Core-Shelled Porous Hybrids as Highly Efficient Catalysts for the Oxygen Reduction Reaction.

    PubMed

    Yuan, Kai; Zhuang, Xiaodong; Fu, Haiyan; Brunklaus, Gunther; Forster, Michael; Chen, Yiwang; Feng, Xinliang; Scherf, Ullrich

    2016-06-01

    Two-dimensional (2D) transition-metal dichalcogenides (TMDs) have drawn much attention due to their unique physical and chemical properties. Using TMDs as templates for the generation of 2D sandwich-like materials with remarkable properties still remains a great challenge due to their poor solvent processability. Herein, MoS2 -coupled sandwich-like conjugated microporous polymers (M-CMPs) with high specific surface area were successfully developed by using functionalized MoS2 nanosheets as template. As-prepared M-CMPs were further used as precursors for preparation of MoS2 -embedded nitrogen-doped porous carbon nanosheets, which were revealed as novel electrocatalysts for oxygen reduction reaction with mainly four-electron transfer mechanism and ultralow half-wave potential in comparison with commercial Pt/C catalyst. Our strategy to core-shelled sandwich-like hybrids paves a way for a new class of 2D hybrids for energy conversion and storage. PMID:27100378

  4. Magnetic response of hybrid ferromagnetic and antiferromagnetic core-shell nanostructures.

    PubMed

    Khan, U; Li, W J; Adeela, N; Irfan, M; Javed, K; Wan, C H; Riaz, S; Han, X F

    2016-03-21

    The synthesis of FeTiO3-Ni(Ni80Fe20) core-shell nanostructures by a two-step method (sol-gel and DC electrodeposition) has been demonstrated. XRD analysis confirms the rhombohedral crystal structure of FeTiO3(FTO) with space group R3[combining macron]. Transmission electron microscopy clearly depicts better morphology of nanostructures with shell thicknesses of ∼25 nm. Room temperature magnetic measurements showed significant enhancement of magnetic anisotropy for the permalloy (Ni80Fe20)-FTO over Ni-FTO core-shell nanostructures. Low temperature magnetic measurements of permalloy-FeTiO3 core-shell structure indicated a strong exchange bias mechanism with magnetic coercivity below the antiferromagnetic Neel temperature (TN = 59 K). The exchange bias is attributed to the alignment of magnetic moments in the antiferromagnetic material at low temperature. Our scheme opens a path towards optimum automotive systems and wireless communications wherein broader bandwidths and smaller sizes are required. PMID:26931335

  5. Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles.

    PubMed

    Tobias, Andrew; Qing, Song; Jones, Marcus

    2016-01-01

    Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores. PMID:26967555

  6. Hybrid Ag@TiO2 core-shell nanostructures with highly enhanced photocatalytic performance.

    PubMed

    Yang, X H; Fu, H T; Wong, K; Jiang, X C; Yu, A B

    2013-10-18

    A new synthetic approach has been developed to prepare silver@titanium dioxide (Ag@TiO2) core-shell nanostructures with controllable size, shape, crystal phase and function at ambient conditions (e.g. in water, ≤100 ° C). This approach shows a few unique features, including short reaction time (a few minutes) for forming core-shell nanostructures, no requirement of high temperature calcinations for generating TiO2 (e.g. at ~100 ° C in our case), tunable TiO2 shell thickness, high yield and good reproducibility. The experimental results show that the Ag@TiO2 core-shell nanostructures exhibit excellent photocatalytic activity compared to the commercial TiO2 (P25) and Ag-doped TiO2 nanocomposite in the degradation of organic dye molecules (e.g. methyl orange) with ultraviolet (UV) irradiation. This could be attributed to the large surface area of TiO2 nanoparticles for maximum harvesting of UV light, mixed anatase and rutile crystalline phases in the TiO2 shell and the effective charge separation between Ag and TiO2 that can reduce the possible recombination of electron-hole (e(-)-h(+)) pairs within TiO2 generated under UV radiation. To further understand the charge separation situation within Ag-TiO2 composites, theoretical simulation (e.g. density functional theory, DFT) was employed in this study. The DFT simulation results indicate that for the Ag@TiO2 core-shell nanostructures, photo-generated electrons transfer readily from the external TiO2 layer to the internal Ag layer with heavy accumulation compared to those doping Ag on TiO2 surfaces, which may reduce the recombination of e(-)-h(+) pairs and thus enhance the photocatalytic efficiency. The findings may open a new strategy to synthesize TiO2-based photocatalysts with highly enhanced efficiency for environmental remediation applications. PMID:24045164

  7. Hybrid Ag@TiO2 core-shell nanostructures with highly enhanced photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Yang, X. H.; Fu, H. T.; Wong, K.; Jiang, X. C.; Yu, A. B.

    2013-10-01

    A new synthetic approach has been developed to prepare silver@titanium dioxide (Ag@TiO2) core-shell nanostructures with controllable size, shape, crystal phase and function at ambient conditions (e.g. in water, ≤100 ° C). This approach shows a few unique features, including short reaction time (a few minutes) for forming core-shell nanostructures, no requirement of high temperature calcinations for generating TiO2 (e.g. at ˜100 ° C in our case), tunable TiO2 shell thickness, high yield and good reproducibility. The experimental results show that the Ag@TiO2 core-shell nanostructures exhibit excellent photocatalytic activity compared to the commercial TiO2 (P25) and Ag-doped TiO2 nanocomposite in the degradation of organic dye molecules (e.g. methyl orange) with ultraviolet (UV) irradiation. This could be attributed to the large surface area of TiO2 nanoparticles for maximum harvesting of UV light, mixed anatase and rutile crystalline phases in the TiO2 shell and the effective charge separation between Ag and TiO2 that can reduce the possible recombination of electron-hole (e--h+) pairs within TiO2 generated under UV radiation. To further understand the charge separation situation within Ag-TiO2 composites, theoretical simulation (e.g. density functional theory, DFT) was employed in this study. The DFT simulation results indicate that for the Ag@TiO2 core-shell nanostructures, photo-generated electrons transfer readily from the external TiO2 layer to the internal Ag layer with heavy accumulation compared to those doping Ag on TiO2 surfaces, which may reduce the recombination of e--h+ pairs and thus enhance the photocatalytic efficiency. The findings may open a new strategy to synthesize TiO2-based photocatalysts with highly enhanced efficiency for environmental remediation applications.

  8. Hybrid parallel code acceleration methods in full-core reactor physics calculations

    SciTech Connect

    Courau, T.; Plagne, L.; Ponicot, A.; Sjoden, G.

    2012-07-01

    When dealing with nuclear reactor calculation schemes, the need for three dimensional (3D) transport-based reference solutions is essential for both validation and optimization purposes. Considering a benchmark problem, this work investigates the potential of discrete ordinates (Sn) transport methods applied to 3D pressurized water reactor (PWR) full-core calculations. First, the benchmark problem is described. It involves a pin-by-pin description of a 3D PWR first core, and uses a 8-group cross-section library prepared with the DRAGON cell code. Then, a convergence analysis is performed using the PENTRAN parallel Sn Cartesian code. It discusses the spatial refinement and the associated angular quadrature required to properly describe the problem physics. It also shows that initializing the Sn solution with the EDF SPN solver COCAGNE reduces the number of iterations required to converge by nearly a factor of 6. Using a best estimate model, PENTRAN results are then compared to multigroup Monte Carlo results obtained with the MCNP5 code. Good consistency is observed between the two methods (Sn and Monte Carlo), with discrepancies that are less than 25 pcm for the k{sub eff}, and less than 2.1% and 1.6% for the flux at the pin-cell level and for the pin-power distribution, respectively. (authors)

  9. Comparison of the magnetic, radiolabeling, hyperthermic and biodistribution properties of hybrid nanoparticles bearing CoFe2O4 and Fe3O4 metal cores.

    PubMed

    Psimadas, D; Baldi, G; Ravagli, C; Comes Franchini, M; Locatelli, E; Innocenti, C; Sangregorio, C; Loudos, G

    2014-01-17

    Metal oxide nanoparticles, hybridized with various polymeric chemicals, represent a novel and breakthrough application in drug delivery, hyperthermia treatment and imaging techniques. Radiolabeling of these nanoformulations can result in new and attractive dual-imaging agents as well as provide accurate in vivo information on their biodistribution profile. In this paper a comparison study has been made between two of the most promising hybrid core-shell nanosystems, bearing either magnetite (Fe3O4) or cobalt ferrite (CoFe2O4) cores, regarding their magnetic, radiolabeling, hyperthermic and biodistribution properties. While hyperthermic properties were found to be affected by the metal-core type, the radiolabeling ability and the in vivo fate of the nanoformulations seem to depend critically on the size and the shell composition. PMID:24334365

  10. Hybrid Co3O4/SnO2 Core-Shell Nanospheres as Real-Time Rapid-Response Sensors for Ammonia Gas.

    PubMed

    Wang, Lili; Lou, Zheng; Zhang, Rui; Zhou, Tingting; Deng, Jianan; Zhang, Tong

    2016-03-16

    Novel hybrid Co3O4/SnO2 core-shell nanospheres have been effectively realized by a one-step hydrothermal, template-free preparation method. Our strategy involves a simple fabrication scheme that entails the coating of natural cross-link agents followed by electrostatic interaction between the positive charges of Sn and Co ions and the negative charge of glutamic acid. The core-shell architecture enables novel flexibility of gas sensor surfaces compared to commonly used bulk materials. The highly efficient charge transfer and unique structure are key to ensuring the availability of high response and rapid-response speed. It demonstrates how hybrid core-shell nanospheres can be used as an advance function material to fabricate electrical sensing devices that may be useful as gas sensors. PMID:26943006

  11. A unified N-body and statistical treatment of stellar dynamics. I - The hybrid code. II - Applications to globular cluster cores

    NASA Technical Reports Server (NTRS)

    Mcmillan, S. L. W.; Lightman, A. P.

    1984-01-01

    A unified N-body and statistical treatment of stellar dynamics is developed and applied to the late stages of core collapse and early stages of post collapse evolution in globular clusters. A 'hybrid' computer code is joined to a direct N-body code which is used to calculate exactly the behavior of particles in the inner spatial region, and the combination is used to follow particles statistically in the outer spatial region. A transition zone allows the exchange of particles and energy between the two regions. The main application results include: formation of a hard central binary system, reversal of core collapse and expansion due to the heat input from this binary, ejection of the binary from the core, and recollapse of the core; density profiles that form a one-parameter sequence during the core oscillations; and indications that these oscillations will eventually cease.

  12. Hybrid silica-gold core-shell nanoparticles for fluorescence enhancement

    NASA Astrophysics Data System (ADS)

    Grzelak, J.; Krajewska, A.; Krajnik, B.; Jamiola, D.; Choma, J.; Jankiewicz, B.; Piątkowski, D.; Nyga, P.; Mackowski, S.

    2016-06-01

    We demonstrate that SiO2 nanoparticles coated with a gold island film (GIF) provide an efficient plasmonic platform for enhancing fluorescence intensity of chlorophyll-containing photosynthetic complexes. Fluorescence images obtained for single SiO2-Au coreshell nanoparticles mixed with photosynthetic complexes reveal very uniform emission patterns of a circular shape, similarly as observed for bare SiO2 nanoparticles. The fluorescence enhancement of chlorophyll emission for SiO2-Au nanostructures is up to four-fold compared to bare SiO2 nanoparticles and shortening of fluorescence decay indicates its plasmonic origin. For doublets or triplets of core-shell SiO2-Au nanoparticles, the intensity of emission is further increased as a result of hot-spot formation at the interfaces of such assemblies.

  13. Hybrid Au-CdSe and Ag-CdSe nanoflowers and core-shell nanocrystals via one-pot heterogeneous nucleation and growth.

    PubMed

    AbouZeid, Khaled M; Mohamed, Mona B; El-Shall, M Samy

    2011-12-01

    A general approach, based on heterogeneous nucleation and growth of CdSe nanostructures on Au or Ag nanocrystals, for the synthesis of Au-CdSe and Ag-CdSe hybrid nanostructures is developed. The new approach provides a versatile one-pot route for the synthesis of hybrid nanoflowers consisting of a gold or silver core and multipod CdSe rods or an intact CdSe shell with controlled thickness, depending on the nucleation and growth parameters. At lower growth temperatures such as 150 °C, the CdSe clusters are adsorbed on the surface of the metal cores in their surface defects, then multiple arms and branches form, resulting in nanoflower-shaped hybrid structures. Increasing the size of the metal core through the choice of the reducing and capping agents results in an improvement of the interface between the metal and CdSe domains, producing core-shell structures. The growth temperature appears to be the most important factor determining the nature of the interface between the metal and CdSe domains. At relatively high temperatures such as 300 °C, the formation of large, faceted Au cores creates preferential growth sites for the CdSe nanocrystalline shell, thus resulting in well-defined Au-CdSe core-shell structures with large interfaces between the Au and CdSe domains. The present approach is expected to foster systematic studies of the electronic structures and optical properties of the metal-semiconductor hybrid materials for potential applications in photovoltaic and nanoelectronic devices. PMID:21994186

  14. Diameter-dependent multiferroic functionality in hybrid core/shell NWs.

    PubMed

    Khan, U; Irfan, M; Li, W J; Adeela, N; Liu, P; Zhang, Q T; Han, X F

    2016-08-11

    A versatile approach towards nanofabrication of highly reproducible Co/BiCoO3 (Co/BCO) core/shell (CS) nanowires (NWs) with different diameters has been adopted by demonstrating easily available and low cost sol-gel and electrodeposition routes. X-ray diffraction (XRD) analysis confirmed the tetragonal system of the BCO nanoshells (NSs) with the space group P4mm. Scanning electron microscopy (SEM) clearly demonstrates the uniform morphology with well aligned CS NWs. The magnetization reversal processes (MRPs), experimentally and with analytical modelling, have been discussed for CS NWs with θ ranging from 0° (in-plane magnetic easy axis) to 90° (out-of-plane magnetic hard axis) with magnetic hysteresis loops and geometrical parameters. Crossover from the vortex to transverse reversal mode on increasing θ has been observed for all diameters. An exchange bias effect has been observed for smaller CS NWs diameters and it is attributed to the shell thickness of ∼25 nm. Furthermore, the magnetic anisotropy effect has been discussed in some detail. PMID:27465910

  15. Core-shell hybrid nanogels for integration of optical temperature-sensing, targeted tumor cell imaging, and combined chemo-photothermal treatment.

    PubMed

    Wu, Weitai; Shen, Jing; Banerjee, Probal; Zhou, Shuiqin

    2010-10-01

    We report a class of core-shell structured hybrid nanogels to demonstrate the conception of integrating the functional building blocks into a single nanoparticle system for simultaneously optical temperature-sensing, cancer cell targeting, fluorescence imaging, and combined chemo-photothermal treatment. The hybrid nanogels were constructed by coating the Ag-Au bimetallic NP core with a thermo-responsive nonlinear poly(ethylene glycol) (PEG)-based hydrogel as shell, and semi-interpenetrating the targeting ligands of hyaluronic acid chains into the surface networks of gel shell. The Ag-Au NP core can emit strong visible fluorescence for imaging of mouse melanoma B16F10 cells. The reversible thermo-responsive volume phase transition of the nonlinear PEG-based gel shell cannot only modify the physicochemical environment of the Ag-Au NP core to manipulate the fluorescence intensity for sensing the environmental temperature change, but also provide a high loading capacity for a model anticancer drug temozolomide and offer a thermo-triggered drug release. The drug release can be induced by both the heat generated by external NIR irradiation and the temperature increase of local environmental media. The ability of the hybrid nanogels to combine the local specific chemotherapy with external NIR photothermal treatment significantly improves the therapeutic efficacy due to a synergistic effect. PMID:20643481

  16. Hybrid light-emitting diodes from anthracene-contained polymer and CdSe/ZnS core/shell quantum dots

    NASA Astrophysics Data System (ADS)

    Tu, Ming-Lung; Su, Yan-Kuin; Chen, Ruei-Tang

    2014-11-01

    In this paper, we added CdSe/ZnS core/shell quantum dots (QDs) into anthracene-contained polymer. The photoluminescent (PL) characteristic of polymer/QD composite film could identify the energy transitions of anthracene-contained polymer and QDs. Furthermore, the electroluminescent (EL) characteristic of hybrid LED also identifies emission peaks of blue polymer and QDs. The maximum luminescence of the device is 970 cd/m2 with 9.1 wt.% QD hybrid emitter. The maximum luminous efficiency is 2.08 cd/A for the same device.

  17. Broadband wavelength tuning of hybrid femtosecond Er/Tm fiber laser system in microstructured suspended-core tellurite fiber

    NASA Astrophysics Data System (ADS)

    Koptev, Maksim Y.; Anashkina, Elena A.; Andrianov, Alexey V.; Dorofeev, Vitaly V.; Kosolapov, Alexey F.; Muravyev, Sergey V.; Kim, Arkady V.

    2016-03-01

    In this study, we propose a widely tunable in the 1.6-2.65 μm range femtosecond fiber laser source, generating high-quality sech-shaped pulses with the duration of order 100 fs. Experimental setup contains hybrid all-fiber Er/Tm pump laser generating 150 fs pulses of 2 nJ in Erbium (1.56 μm) channel and 125 fs pulses of 4 nJ in Thulium (2 μm) channel respectively. This laser source was coupled to a 50 cm piece of suspended-core microstructured TeO2-WO3- La2O3 glass fiber with launching efficiency of about 10%. We have observed Raman self-frequency shifting solitons in this fiber with maximum red shift of 2.25 μm for Erbium channel and 2.65 μm for Thulium channel. By varying energy of pump pulses, solitons can be tuned in broadband spectral region. We have made theoretical studies of nonlinear pulse dynamics in the tellurite fiber with carefully measured and calculated parameters. Numerical simulation is in a very good agreement with the experiment

  18. SiC@Si core-shell nanowires on carbon paper as a hybrid anode for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Wang, Yewu; Gu, Lin; Lu, Ren; Qian, Haolei; Peng, Xinsheng; Sha, Jian

    2015-10-01

    Silicon has been considered as one of the most promising anode materials for the next generation lithium-ion battery due to its high theoretical capacity, but large volume changes during the electrochemical cycling limit its commercial application. In this study, we report the synthesis of silicon carbide @ silicon core-shell nanowires on carbon paper and their application in lithium-ion batteries. The hybrid nano-structures are fabricated via a two-step chemical vapor deposition method and directly used as the working electrode without any additional binder, exhibiting high specific capacity, high coulombic efficiency and good cycling stability. After 50 cycles, the discharge capacities still remain 2837 and 1809 mAh g-1 at the rates of 0.1C and 0.5C, respectively. Furthermore, we also study the influence of the growth time of SiC NWs and the thickness of Si film on the lithium-ion batteries' performance, and propose the possible method to further improve the battery performance.

  19. Ultrasensitive electrochemical sensor for Hg(2+) by using hybridization chain reaction coupled with Ag@Au core-shell nanoparticles.

    PubMed

    Li, Zongbing; Miao, Xiangmin; Xing, Ke; Peng, Xue; Zhu, Aihua; Ling, Liansheng

    2016-06-15

    A novel electrochemical biosensor for Hg(2+) detection was reported by using DNA-based hybridization chain reaction (HCR) coupled with positively charged Ag@Au core-shell nanoparticles ((+)Ag@Au CSNPs) amplification. To construct the sensor, capture probe (CP ) was firstly immobilized onto the surface of glass carbon electrode (GCE). In the presence of Hg(2+), the sandwiched complex can be formed between the immobilized CP on the electrode surface and the detection probe (DP) modified on the gold nanoparticles (AuNPs) based on T-Hg(2+)-T coordination chemistry. The carried DP then opened two ferrocene (Fc) modified hairpin DNA (H1 and H2) in sequence and propagated the happen of HCR to form a nicked double-helix. Numerous Fc molecules were formed on the neighboring probe and produced an obvious electrochemical signal. Moreover, (+)Ag@Au CSNPs were assembly onto such dsDNA polymers as electrochemical signal enhancer. Under optimal conditions, such sensor presents good electrochemical responses for Hg(2+) detection with a detection limit of 3.6 pM. Importantly, the methodology has high selectivity for Hg(2+) detection. PMID:26852203

  20. Exchange bias in two-step artificially grown one-dimensional hybrid Co-BiFeO3 core-shell nanostructures.

    PubMed

    Ali, S S; Li, W J; Javed, K; Shi, D W; Riaz, S; Zhai, G J; Han, X F

    2016-01-29

    One-dimensional core-shell nanostructures consisting of a ferromagnetic cobalt core and a multiferroic BiFeO3 (BFO) shell were fabricated by an artificial two-step methodology. The coupling between the ferromagnetic core and multiferroic shell manifests a significant exchange bias effect which gives a clear demonstration of the anti-ferromagnetic functionality of the BFO shell material. Exchange biases of 30 Oe and 60 Oe are observed at 300 K and at 5 K, respectively. Superparamagnetic contributions at lower temperatures play an important role in contributing to overall magnetic behavior. Dominant shape anisotropy causes parallel alignment of the easy magnetization axis along the axis of core-shell nanowires. A coherent mode of the magnetization reversal mechanism is observed by the angular dependence of coercivity (H c). This versatile two-step methodology can be employed to fabricate and investigate many other hybrid nanostructures leading to a vast scope of investigation for researchers. PMID:26656305

  1. Exchange bias in two-step artificially grown one-dimensional hybrid Co-BiFeO3 core-shell nanostructures

    NASA Astrophysics Data System (ADS)

    Ali, S. S.; Li, W. J.; Javed, K.; Shi, D. W.; Riaz, S.; Zhai, G. J.; Han, X. F.

    2016-01-01

    One-dimensional core-shell nanostructures consisting of a ferromagnetic cobalt core and a multiferroic BiFeO3 (BFO) shell were fabricated by an artificial two-step methodology. The coupling between the ferromagnetic core and multiferroic shell manifests a significant exchange bias effect which gives a clear demonstration of the anti-ferromagnetic functionality of the BFO shell material. Exchange biases of 30 Oe and 60 Oe are observed at 300 K and at 5 K, respectively. Superparamagnetic contributions at lower temperatures play an important role in contributing to overall magnetic behavior. Dominant shape anisotropy causes parallel alignment of the easy magnetization axis along the axis of core-shell nanowires. A coherent mode of the magnetization reversal mechanism is observed by the angular dependence of coercivity (H c). This versatile two-step methodology can be employed to fabricate and investigate many other hybrid nanostructures leading to a vast scope of investigation for researchers.

  2. Rapid synthesis and characterization of hybrid ZnO@Au core-shell nanorods for high performance, low temperature NO2 gas sensor applications

    NASA Astrophysics Data System (ADS)

    Ponnuvelu, Dinesh Veeran; Pullithadathil, Biji; Prasad, Arun K.; Dhara, Sandip; Ashok, Anuradha; Mohamed, Kamruddin; Tyagi, Ashok Kumar; Raj, Baldev

    2015-11-01

    A rapid synthesis route for hybrid ZnO@Au core-shell nanorods has been realized for ultrasensitive, trace-level NO2 gas sensor applications. ZnO nanorods and hybrid ZnO@Au core-shell nanorods are structurally analyzed using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Optical characterization using UV-visible (UV-vis), photoluminescence (PL) and Raman spectroscopies elucidate alteration in the percentage of defect and charge transport properties of ZnO@Au core-shell nanorods. The study reveals the accumulation of electrons at metal-semiconductor junctions leading to upward band bending for ZnO and thus favors direct electron transfer from ZnO to Au nanoclusters, which mitigates charge carrier recombination process. The operating temperature of ZnO@Au core-shell nanorods based sensor significantly decreased to 150 °C compared to alternate NO2 sensors (300 °C). Moreover, a linear sensor response in the range of 0.5-5 ppm of NO2 concentration was observed with a lowest detection limit of 500 ppb using conventional electrodes. The defects with deep level, observed in ZnO nanorods and hybrid ZnO@Au core-shell nanorods influences local electron density, which in-turn indirectly influence the gas sensing properties. The ZnO@Au core-shell nanorods based sensor exhibited good selectivity toward NO2 and was found to be very stable.

  3. Numerical investigation of the vortex core precession in a model hydro turbine with the aid of hybrid methods for computation of turbulent flows

    NASA Astrophysics Data System (ADS)

    Sentyabov, A. V.; Gavrilov, A. A.; Dekterev, A. A.; Minakov, A. V.

    2014-12-01

    Numerical modeling of the unsteady flow in the draft tube of the test bench hydro turbine is conducted. The hybrid RANS-LES methods for modeling turbulent flows are compared. The intensity and frequency of pressure fluctuations, which are induced by the vortex core precession under the runner, and the integral characteristics are considered. An analysis of the synchronous and asynchronous parts of pressure fluctuations is done; the generating and influence of the synchronous component of fluctuations are considered. The vortex core interaction with the draft tube elbow is considered.

  4. Hybrid core-shell nanowire electrodes utilizing vertically aligned carbon nanofiber arrays for high-performance energy storage

    NASA Astrophysics Data System (ADS)

    Klankowski, Steven Arnold

    Nanostructured electrode materials for electrochemical energy storage systems have been shown to improve both rate performance and capacity retention, while allowing considerably longer cycling lifetime. The nano-architectures provide enhanced kinetics by means of larger surface area, higher porosity, better material interconnectivity, shorter diffusion lengths, and overall mechanical stability. Meanwhile, active materials that once were excluded from use due to bulk property issues are now being examined in new nanoarchitecture. Silicon was such a material, desired for its large lithium-ion storage capacity of 4,200 mAh g-1 and low redox potential of 0.4 V vs. Li/Li+; however, a ˜300% volume expansion and increased resistivity upon lithiation limited its broader applications. In the first study, the silicon-coated vertically aligned carbon nanofiber (VACNF) array presents a unique core-shell nanowire (NW) architecture that demonstrates both good capacity and high rate performance. In follow-up, the Si-VACNFs NW electrode demonstrates enhanced power rate capabilities as it shows excellent storage capacity at high rates, attributed to the unique nanoneedle structure that high vacuum sputtering produces on the three-dimensional array. Following silicon's success, titanium dioxide has been explored as an alternative high-rate electrode material by utilizing the dual storage mechanisms of Li+ insertion and pseudocapacitance. The TiO 2-coated VACNFs shows improved electrochemical activity that delivers near theoretical capacity at larger currents due to shorter Li+ diffusion lengths and highly effective electron transport. A unique cell is formed with the Si-coated and TiO2-coated electrodes place counter to one another, creating the hybrid of lithium ion battery-pseudocapacitor that demonstrated both high power and high energy densities. The hybrid cell operates like a battery at lower current rates, achieving larger discharge capacity, while retaining one-third of

  5. Effective photocatalytic dechlorination of 2,4-dichlorophenol by a novel graphene encapsulated ZnO/Co3O4 core-shell hybrid under visible light.

    PubMed

    Rakibuddin, Md; Ananthakrishnan, Rajakumar

    2016-01-01

    In the present work, a graphene encapsulated ZnO/Co3O4 (GE/ZnO/Co3O4) core-shell hybrid is fabricated through a facile self-assembly approach, where the mutual electrostatic interaction force drives the ZnO/Co3O4 heteronanostructures to be fully wrapped with flexible ultrathin graphene shells. The as-prepared GE/ZnO/Co3O4 core-shell hybrid is characterized and exhibits excellent visible light photocatalytic ability toward dechlorination of 2,4-dichlorophenol (2,4-DCP) in the aqueous phase. It is worth noting that 2,4-DCP is almost completely mineralized into CO2 and H2O by the GE/ZnO/Co3O4 after 5 h of a photocatalytic reaction. This type of higher dechlorination and mineralization efficiency of 2,4-DCP is not generally observed, and is found to be higher than some previous studies. The dechlorination of 2,4-DCP has been achieved under different parametric conditions. The unique architecture of the GE/ZnO/Co3O4 core-shell hybrid also provides high stability and recyclability towards degradation of 2,4-DCP. The higher photocatalytic activity of the hybrid can be ascribed to the synergistic effect of ZnO, Co3O4 and graphene, and also by an increase in the contact surface between the metal oxide core and the graphene shell, which acts as a continuous path for rapid electron transport to offer a greater number of reactive species. PMID:26677128

  6. 3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application

    NASA Astrophysics Data System (ADS)

    Ke, Qingqing; Zheng, Minrui; Liu, Huajun; Guan, Cao; Mao, Lu; Wang, John

    2015-09-01

    Three dimensional hierarchical nanostructures have attracted great attention for electrochemical energy storage applications. In this work, self-supported TiO2@Ni(OH)2 core-shell nanowire arrays are prepared on carbon fiber paper via the combination of hydrothermal synthesis and chemical bath deposition. In this core-shell hybrid, the morphology and wall size of the interconnected nanoflake shell of Ni(OH)2 can be tuned through adjusting the concentration of ammonia solution. Heterogeneous nucleation and subsequent oriented crystal growth are identified to be the synthesis mechanism affecting the nanostructure of the shell material, which consequently determines the electrochemical performance in both energy storage and charge transfer. Superior capabilities of 264 mAhg-1 at 1 A g-1 and 178 mAh g-1 at 10 A g-1 are achieved with the core-shell hybrids of the optimized structure. The asymmetric supercapacitor prototype, comprising of TiO2@Ni(OH)2 as the anode and mesoporous carbons (MCs) as the cathode, is shown to exhibit superior electrochemical performance with high energy and power densities. The present work provides a clear illustration of the structure-property relationship in nanocrystal synthesis and offers a potential strategy to enhance the battery type Ni(OH)2 electrode in a hybrid supercapacitor device.

  7. 3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application.

    PubMed

    Ke, Qingqing; Zheng, Minrui; Liu, Huajun; Guan, Cao; Mao, Lu; Wang, John

    2015-01-01

    Three dimensional hierarchical nanostructures have attracted great attention for electrochemical energy storage applications. In this work, self-supported TiO2@Ni(OH)2 core-shell nanowire arrays are prepared on carbon fiber paper via the combination of hydrothermal synthesis and chemical bath deposition. In this core-shell hybrid, the morphology and wall size of the interconnected nanoflake shell of Ni(OH)2 can be tuned through adjusting the concentration of ammonia solution. Heterogeneous nucleation and subsequent oriented crystal growth are identified to be the synthesis mechanism affecting the nanostructure of the shell material, which consequently determines the electrochemical performance in both energy storage and charge transfer. Superior capabilities of 264 mAh g(-1) at 1 A g(-1) and 178 mAh g(-1) at 10 A g(-1) are achieved with the core-shell hybrids of the optimized structure. The asymmetric supercapacitor prototype, comprising of TiO2@Ni(OH)2 as the anode and mesoporous carbons (MCs) as the cathode, is shown to exhibit superior electrochemical performance with high energy and power densities. The present work provides a clear illustration of the structure-property relationship in nanocrystal synthesis and offers a potential strategy to enhance the battery type Ni(OH)2 electrode in a hybrid supercapacitor device. PMID:26353970

  8. 3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application

    PubMed Central

    Ke, Qingqing; Zheng, Minrui; Liu, Huajun; Guan, Cao; Mao, Lu; Wang, John

    2015-01-01

    Three dimensional hierarchical nanostructures have attracted great attention for electrochemical energy storage applications. In this work, self-supported TiO2@Ni(OH)2 core-shell nanowire arrays are prepared on carbon fiber paper via the combination of hydrothermal synthesis and chemical bath deposition. In this core-shell hybrid, the morphology and wall size of the interconnected nanoflake shell of Ni(OH)2 can be tuned through adjusting the concentration of ammonia solution. Heterogeneous nucleation and subsequent oriented crystal growth are identified to be the synthesis mechanism affecting the nanostructure of the shell material, which consequently determines the electrochemical performance in both energy storage and charge transfer. Superior capabilities of 264 mAhg−1 at 1 A g−1 and 178 mAh g−1 at 10 A g−1 are achieved with the core-shell hybrids of the optimized structure. The asymmetric supercapacitor prototype, comprising of TiO2@Ni(OH)2 as the anode and mesoporous carbons (MCs) as the cathode, is shown to exhibit superior electrochemical performance with high energy and power densities. The present work provides a clear illustration of the structure-property relationship in nanocrystal synthesis and offers a potential strategy to enhance the battery type Ni(OH)2 electrode in a hybrid supercapacitor device. PMID:26353970

  9. Carbon/SnO2/carbon core/shell/shell hybrid nanofibers: tailored nanostructure for the anode of lithium ion batteries with high reversibility and rate capacity

    NASA Astrophysics Data System (ADS)

    Kong, Junhua; Liu, Zhaolin; Yang, Zhengchun; Tan, Hui Ru; Xiong, Shanxin; Wong, Siew Yee; Li, Xu; Lu, Xuehong

    2012-01-01

    A carbon/SnO2/carbon core/shell/shell hybrid nanofibrous mat was successfully prepared via single-spinneret electrospinning followed by carbonization and hydrothermal treatment. The morphology and structure of carbon/SnO2/carbon hybrid nanofibers were characterized by field-emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, wide-angle X-ray diffraction and X-ray photoelectron spectroscopy, and their electrochemical properties were studied as an anode in lithium ion batteries (LIBs). It is shown that the designed hybrid nanofibrous mat exhibits excellent electrochemical properties, including high reversible capacity with high columbic efficiency and impressive rate capacity. The greatly enhanced electrochemical performance is mainly due to the morphological stability and reduced diffusion resistance, which are induced by both the carbon core and deposited carbon skin. Furthermore, the embedded and de-aggregated SnO2 nanoparticles in the carbon phase, which are less than 10 nm in size, provide large numbers of reaction sites for lithium ions and ensure complete alloying with them.A carbon/SnO2/carbon core/shell/shell hybrid nanofibrous mat was successfully prepared via single-spinneret electrospinning followed by carbonization and hydrothermal treatment. The morphology and structure of carbon/SnO2/carbon hybrid nanofibers were characterized by field-emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, wide-angle X-ray diffraction and X-ray photoelectron spectroscopy, and their electrochemical properties were studied as an anode in lithium ion batteries (LIBs). It is shown that the designed hybrid nanofibrous mat exhibits excellent electrochemical properties, including high reversible capacity with high columbic efficiency and impressive rate capacity. The greatly enhanced electrochemical performance is mainly due to the morphological stability and reduced diffusion

  10. Charge collection enhancement by incorporation of gold-silica core-shell nanoparticles into P3HT:PCBM/ZnO nanorod array hybrid solar cells.

    PubMed

    Wang, Ting-Chung; Su, Yen-Hsun; Hung, Yun-Kai; Yeh, Chen-Sheng; Huang, Li-Wen; Gomulya, Widianta; Lai, Lai-Hung; Loi, Maria A; Yang, Jih-Sheng; Wu, Jih-Jen

    2015-08-14

    In this work, gold-silica core-shell (Au@silica) nanoparticles (NPs) with various silica-shell thicknesses are incorporated into P3HT:PCBM/ZnO nanorod (NR) hybrid solar cells. Enhancement in the short-circuit current density and the efficiency of the hybrid solar cells is attained with the appropriate addition of Au@silica NPs regardless of the silica-shell thickness. Compared to the P3HT:PCBM/ZnO NR hybrid solar cell, a 63% enhancement in the efficiency is achieved by the P3HT:PCBM/Au@silica NP/ZnO NR hybrid solar cell. The finite difference time domain simulations indicate that the strength of the Fano resonance, i.e., the electric field of the quasi-static asymmetric quadrupole, on the surface of Au@silica NPs in the P3HT:PCBM/ZnO NR hybrid significantly decreases with increasing thickness of the silica shell. Raman characterization reveals that the degree of P3HT order increases when Au@silica NPs are incorporated into the P3HT:PCBM/ZnO NR hybrid. The charge separation at the interface between P3HT and PCBM as well as the electron transport in the active layer are retarded by the electric field of the Fano resonance. Nevertheless, the prolongation of the electron lifetime and the reduction of the electron transit time in the P3HT:PCBM/ZnO NR hybrid solar cells, which result in an enhancement of electron collection, are achieved by the addition of Au@silica NPs. This may be attributed to the improvement in the degree of P3HT order and connectivity of PCBM when Au@silica NPs are incorporated into the P3HT:PCBM active layer. PMID:26159896

  11. Multi-functional core-shell hybrid nanogels for pH-dependent magnetic manipulation, fluorescent pH-sensing, and drug delivery.

    PubMed

    Wu, Weitai; Shen, Jing; Gai, Zheng; Hong, Kunlun; Banerjee, Probal; Zhou, Shuiqin

    2011-12-01

    Remotely optical sensing and drug delivery using an environmentally-guided magnetically-driven hybrid nanogel particle could allow for medical diagnostics and treatment. Such multifunctional hybrid nanogels (<200 nm) were prepared through the first synthesis of magnetic Ni NPs, followed by a moderate growth of fluorescent metallic Ag on the surface of Ni NPs, and then a coverage of a pH-responsive copolymer gel shell of poly(ethylene glycol-co-methacrylic acid) [p(EG-MAA)] onto the Ni-Ag bimetallic NP cores (18 ± 5 nm). The introduction of the pH-responsive p(EG-MAA) gel shell onto the magnetic and fluorescent Ni-Ag NPs makes the polymer-bound Ni-Ag NPs responsive to pH over the physiologically important range 5.0-7.4. The hybrid nanogels can adapt to surrounding pH and regulate the sensitivity in response to external magnetic field (such as a small magnet of 0.1 T), resulting in the accumulation of the hybrid nanogels within the duration from hours to a few seconds as the pH value decreases from 7.4 to 5.0. The pH-dependent magnetic response characteristic of the hybrid nanogels were further integrated with the pH change to fluorescent signal transduction and pH-regulated anticancer drug (a model drug 5-fluorouracil) delivery functions. The hybrid nanogels can overcome cellular barriers to enter the intracellular region and light up the mouse melanoma B16F10 cells. The multiple responsive hybrid nanogel that can be manipulated in tandem endogenous and exogenous activation should enhance our ability to address the complexity of biological systems. PMID:21944827

  12. Multi-responsive hybrid particles: thermo-, pH-, photo-, and magneto-responsive magnetic hydrogel cores with gold nanorod optical triggers

    NASA Astrophysics Data System (ADS)

    Rittikulsittichai, Supparesk; Kolhatkar, Arati G.; Sarangi, Subhasis; Vorontsova, Maria A.; Vekilov, Peter G.; Brazdeikis, Audrius; Randall Lee, T.

    2016-06-01

    The research strategy described in this manuscript harnesses the attractive properties of hydrogels, gold nanorods (Aurods), and magnetic nanoparticles (MNPs) by synthesizing one unique multi-responsive nanostructure. This novel hybrid structure consists of silica-coated magnetic particles encapsulated within a thermo-responsive P(NIPAM-co-AA) hydrogel network on which Aurods are assembled. Furthermore, this research demonstrates that these composite particles respond to several forms of external stimuli (temperature, pH, light, and/or applied magnetic field) owing to their specific architecture. Exposure of the hybrid particles to external stimuli led to a systematic and reversible variation in the hydrodynamic diameter (swelling-deswelling) and thus in the optical properties of the hybrid particles (red-shifting of the plasmon band). Such stimuli-responsive volume changes can be effectively exploited in drug-delivery applications.The research strategy described in this manuscript harnesses the attractive properties of hydrogels, gold nanorods (Aurods), and magnetic nanoparticles (MNPs) by synthesizing one unique multi-responsive nanostructure. This novel hybrid structure consists of silica-coated magnetic particles encapsulated within a thermo-responsive P(NIPAM-co-AA) hydrogel network on which Aurods are assembled. Furthermore, this research demonstrates that these composite particles respond to several forms of external stimuli (temperature, pH, light, and/or applied magnetic field) owing to their specific architecture. Exposure of the hybrid particles to external stimuli led to a systematic and reversible variation in the hydrodynamic diameter (swelling-deswelling) and thus in the optical properties of the hybrid particles (red-shifting of the plasmon band). Such stimuli-responsive volume changes can be effectively exploited in drug-delivery applications. Electronic supplementary information (ESI) available: Contains detailed information about the synthesis of

  13. Core-shell LiFePO4 /carbon-coated reduced graphene oxide hybrids for high-power lithium-ion battery cathodes.

    PubMed

    Ha, Sung Hoon; Lee, Yun Jung

    2015-01-26

    Core-shell carbon-coated LiFePO4 nanoparticles were hybridized with reduced graphene (rGO) for high-power lithium-ion battery cathodes. Spontaneous aggregation of hydrophobic graphene in aqueous solutions during the formation of composite materials was precluded by employing hydrophilic graphene oxide (GO) as starting templates. The fabrication of true nanoscale carbon-coated LiFePO4 -rGO (LFP/C-rGO) hybrids were ascribed to three factors: 1) In-situ polymerization of polypyrrole for constrained nanoparticle synthesis of LiFePO4 , 2) enhanced dispersion of conducting 2D networks endowed by colloidal stability of GO, and 3) intimate contact between active materials and rGO. The importance of conducting template dispersion was demonstrated by contrasting LFP/C-rGO hybrids with LFP/C-rGO composites in which agglomerated rGO solution was used as the starting templates. The fabricated hybrid cathodes showed superior rate capability and cyclability with rates from 0.1 to 60 C. This study demonstrated the synergistic combination of nanosizing with efficient conducting templates to afford facile Li(+) ion and electron transport for high power applications. PMID:25430976

  14. Growth of GaN@InGaN Core-Shell and Au-GaN Hybrid Nanostructures for Energy Applications

    DOE PAGESBeta

    Kuykendall, Tevye; Aloni, Shaul; Jen-La Plante, Ilan; Mokari, Taleb

    2009-01-01

    We demonstrated a method to control the bandgap energy of GaN nanowires by forming GaN@InGaN core-shell hybrid structures using metal organic chemical vapor deposition (MOCVD). Furthermore, we show the growth of Au nanoparticles on the surface of GaN nanowires in solution at room temperature. The work shown here is a first step toward engineering properties that are crucial for the rational design and synthesis of a new class of photocatalytic materials. The hybrid structures were characterized by various techniques, including photoluminescence (PL), energy dispersive x-ray spectroscopy (EDS), transmission and scanning electron microscopy (TEM and SEM), and x-ray diffraction (XRD).

  15. The features of neutronic calculations for fast reactors with hybrid cores on the basis of BFS-62-3A critical assembly experiments

    SciTech Connect

    Mitenkova, E. F.; Novikov, N. V.; Blokhin, A. I.

    2012-07-01

    The different (U-Pu) fuel compositions are considered for next generation of sodium fast breeder reactors. The considerable discrepancies in axial and radial neutron spectra for hybrid reactor systems compared to the cores with UO{sub 2} fuel cause increasing uncertainty of generating the group nuclear constants in those reactor systems. The calculation results of BFS-62-3A critical assembly which is considered as full-scale model of BN-600 hybrid core with steel reflector specify quite different spectra in local areas. For those systems the MCNP 5 calculations demonstrate significant sensitivity of effective multiplication factor K{sub eff} and spectral indices to nuclear data libraries. For {sup 235}U, {sup 238}U, {sup 239}Pu the results of calculated radial fission rate distributions against the reconstructed ones are analyzed. Comparative analysis of spectral indices, neutron spectra and radial fission rate distributions are performed using the different versions of ENDF/B, JENDL-3.3, JENDL-4, JEFF-3.1.1 libraries and BROND-3 for Fe, Cr isotopes. For analyzing the fission rate sensitivity to the plutonium presence in the fuel {sup 239}Pu is substituted for {sup 235}U (enrichment 90%) in the FA areas containing the plutonium. For {sup 235}U, {sup 238}U, {sup 239}Pu radial fission rate distributions the explanation of pick values discrepancies is based on the group fission constants analyses and possible underestimation of some features at the experimental data recovery method (Westcott factors, temperature dependence). (authors)

  16. Co@Co3O4 core-shell particle encapsulated N-doped mesoporous carbon cage hybrids as active and durable oxygen-evolving catalysts.

    PubMed

    Li, Xinzhe; Fang, Yiyun; Wen, Lixin; Li, Feng; Yin, Guanlin; Chen, Wanmin; An, Xingcai; Jin, Jun; Ma, Jiantai

    2016-04-01

    Cobalt-based nanomaterials are promising candidates as efficient, affordable, and sustainable alternative electrocatalysts for the oxygen evolution reaction (OER). However, the catalytic efficiency of traditional nanomaterials is still far below what is expected, because of their low stability in basic solutions and poor active site exposure yield. Here a unique hybrid nanomaterial comprising Co@Co3O4 core-shell nanoparticle (NP) encapsulated N-doped mesoporous carbon cages on reduced graphene oxide (denoted as Co@Co3O4@NMCC/rGO) is successfully synthesized via a carbonization and subsequent oxidation strategy of a graphene oxide (GO)-based metal-organic framework (MOF). Impressively, the special carbon cage structure is very important for not only leading to a large active surface area, enhanced mass/charge transport capability, and easy release of gas bubbles, but also preventing Co@Co3O4 NPs from aggregation and peeling off during prolonged electrochemical reactions. As a result, in alkaline media, the resulting hybrid materials catalyze the OER with a low onset potential of ∼1.50 V (vs. RHE) and an over-potential of only 340 mV to achieve a stable current density of 10 mA cm(-2) for at least 25 h. In addition, metallic Co cores in Co@Co3O4 provide an alternative way for electron transport and accelerate the OER rate. PMID:26914166

  17. Intermodal and cross-polarization four-wave mixing in large-core hybrid photonic crystal fibers.

    PubMed

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-03-01

    Degenerate four-wave mixing is considered in large mode area hybrid photonic crystal fibers, combining photonic bandgap guidance and index guidance. Co- and orthogonally polarized pump, signal and idler fields are considered numerically by calculating the parametric gain and experimentally by spontaneous degenerate four-wave mixing. Intermodal and birefringence assisted intramodal phase matching is observed. Good agreement between calculations and experimental observations is obtained. Intermodal four-wave mixing is achieved experimentally with a conversion efficiency of 17%. PMID:25836821

  18. Binder-free Co3O4@NiCoAl-layered double hydroxide core-shell hybrid architectural nanowire arrays with enhanced electrochemical performance

    NASA Astrophysics Data System (ADS)

    Li, Xuan; Yang, Zhengchun; Qi, Wen; Li, Yutao; Wu, Ying; Zhou, Shaoxiong; Huang, Shengming; Wei, Jun; Li, Huijun; Yao, Pei

    2016-02-01

    Herein, binder-free Co3O4@NiCoAl-layered double hydroxide (Co3O4@LDH) core-shell hybrid architectural nanowire arrays were prepared via a two-step hydrothermal synthesis route. LDH nanosheets possessing a large electroactive surface area uniformly dispersed on the surface of Co3O4 nanowires were successfully fabricated allowing for fast electron transport that enhances the electrochemical performance of LDH nanosheets. Co3O4@LDH nanowire arrays of 2 to 1.5 molar ratio (Co3O4:LDH) exhibit high specific capacitance (1104 F g-1 at 1 A g-1), adequate rate capability and cycling stability (87.3% after 5000 cycles), attributed to the synergistic effect between the robust Co3O4 nanowire arrays and LDH nanosheets.

  19. MC64-ClustalWP2: a highly-parallel hybrid strategy to align multiple sequences in many-core architectures.

    PubMed

    Díaz, David; Esteban, Francisco J; Hernández, Pilar; Caballero, Juan Antonio; Guevara, Antonio; Dorado, Gabriel; Gálvez, Sergio

    2014-01-01

    We have developed the MC64-ClustalWP2 as a new implementation of the Clustal W algorithm, integrating a novel parallelization strategy and significantly increasing the performance when aligning long sequences in architectures with many cores. It must be stressed that in such a process, the detailed analysis of both the software and hardware features and peculiarities is of paramount importance to reveal key points to exploit and optimize the full potential of parallelism in many-core CPU systems. The new parallelization approach has focused into the most time-consuming stages of this algorithm. In particular, the so-called progressive alignment has drastically improved the performance, due to a fine-grained approach where the forward and backward loops were unrolled and parallelized. Another key approach has been the implementation of the new algorithm in a hybrid-computing system, integrating both an Intel Xeon multi-core CPU and a Tilera Tile64 many-core card. A comparison with other Clustal W implementations reveals the high-performance of the new algorithm and strategy in many-core CPU architectures, in a scenario where the sequences to align are relatively long (more than 10 kb) and, hence, a many-core GPU hardware cannot be used. Thus, the MC64-ClustalWP2 runs multiple alignments more than 18x than the original Clustal W algorithm, and more than 7x than the best x86 parallel implementation to date, being publicly available through a web service. Besides, these developments have been deployed in cost-effective personal computers and should be useful for life-science researchers, including the identification of identities and differences for mutation/polymorphism analyses, biodiversity and evolutionary studies and for the development of molecular markers for paternity testing, germplasm management and protection, to assist breeding, illegal traffic control, fraud prevention and for the protection of the intellectual property (identification

  20. MC64-ClustalWP2: A Highly-Parallel Hybrid Strategy to Align Multiple Sequences in Many-Core Architectures

    PubMed Central

    Díaz, David; Esteban, Francisco J.; Hernández, Pilar; Caballero, Juan Antonio; Guevara, Antonio

    2014-01-01

    We have developed the MC64-ClustalWP2 as a new implementation of the Clustal W algorithm, integrating a novel parallelization strategy and significantly increasing the performance when aligning long sequences in architectures with many cores. It must be stressed that in such a process, the detailed analysis of both the software and hardware features and peculiarities is of paramount importance to reveal key points to exploit and optimize the full potential of parallelism in many-core CPU systems. The new parallelization approach has focused into the most time-consuming stages of this algorithm. In particular, the so-called progressive alignment has drastically improved the performance, due to a fine-grained approach where the forward and backward loops were unrolled and parallelized. Another key approach has been the implementation of the new algorithm in a hybrid-computing system, integrating both an Intel Xeon multi-core CPU and a Tilera Tile64 many-core card. A comparison with other Clustal W implementations reveals the high-performance of the new algorithm and strategy in many-core CPU architectures, in a scenario where the sequences to align are relatively long (more than 10 kb) and, hence, a many-core GPU hardware cannot be used. Thus, the MC64-ClustalWP2 runs multiple alignments more than 18x than the original Clustal W algorithm, and more than 7x than the best x86 parallel implementation to date, being publicly available through a web service. Besides, these developments have been deployed in cost-effective personal computers and should be useful for life-science researchers, including the identification of identities and differences for mutation/polymorphism analyses, biodiversity and evolutionary studies and for the development of molecular markers for paternity testing, germplasm management and protection, to assist breeding, illegal traffic control, fraud prevention and for the protection of the intellectual property (identification

  1. Self-assembly of multiferroic core-shell particulate nanocomposites through DNA-DNA hybridization and magnetic field directed assembly of superstructures

    NASA Astrophysics Data System (ADS)

    Sreenivasulu, Gollapudi; Lochbiler, Thomas A.; Panda, Manashi; Srinivasan, Gopalan; Chavez, Ferman A.

    2016-04-01

    Multiferroic composites of ferromagnetic and ferroelectric phases are of importance for studies on mechanical strain mediated coupling between the magnetic and electric subsystems. This work is on DNA-assisted self-assembly of superstructures of such composites with nanometer periodicity. The synthesis involved oligomeric DNA-functionalized ferroelectric and ferromagnetic nanoparticles, 600 nm BaTiO3 (BTO) and 200 nm NiFe2O4 (NFO), respectively. Mixing BTO and NFO particles, possessing complementary DNA sequences, resulted in the formation of ordered core-shell heteronanocomposites held together by DNA hybridization. The composites were imaged by scanning electron microscopy and scanning microwave microscopy. The presence of heteroassemblies along with core-shell architecture is clearly observed. The reversible nature of the DNA hybridization allows for restructuring the composites into mm-long linear chains and 2D-arrays in the presence of a static magnetic field and ring-like structures in a rotating-magnetic field. Strong magneto-electric (ME) coupling in as-assembled composites is evident from static magnetic field H induced polarization and low-frequency magnetoelectric voltage coefficient measurements. Upon annealing the nanocomposites at high temperatures, evidence for the formation of bulk composites with excellent cross-coupling between the electric and magnetic subsystems is obtained by H-induced polarization and low-frequency ME voltage coefficient. The ME coupling strength in the self-assembled composites is measured to be much stronger than in bulk composites with randomly distributed NFO and BTO prepared by direct mixing and sintering.

  2. Core-Shell γ-Fe2O3/SiO2/PCA/Ag-NPs Hybrid Nanomaterials as a New Candidate for Future Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Soleyman, R.; Pourjavadi, A.; Masoud, N.; Varamesh, A.

    2014-04-01

    In the current study, γ-Fe2O3/SiO2/PCA/Ag-NPs hybrid nanomaterials were successfully synthesized and characterized. At first, prepared γ-Fe2O3 core nanoparticles were modified by SiO2 layer. Then they were covered by poly citric acid (PCA) via melting esterification method as well. PCA shell acts as an effective linker, and provides vacancies for conveying drugs. Moreover, this shell as an effective capping agent directs synthesis of silver nanoparticles (Ag-NPs) via in situ photo-reduction of silver ions by sunlight-UV irradiation. This system has several benefits as a suitable cancer therapy nanomaterial. Magnetic nanoparticles (MNPs) can guide Ag-NPs and drugs to cancer cells and then Ag-NPs can affect those cells via Ag-NPs anti-angiogenesis effect. Size and structure of the prepared magnetic hybrid nanomaterials were characterized using FTIR and UV-Vis spectra, AFM and TEM pictures and XRD data.

  3. Hybrid nanocarbon as a catalyst for direct dehydrogenation of propane: formation of an active and selective core-shell sp2/sp3 nanocomposite structure.

    PubMed

    Wang, Rui; Sun, Xiaoyan; Zhang, Bingsen; Sun, Xiaoying; Su, Dangsheng

    2014-05-19

    Hybrid nanocarbon, comprised of a diamond core and a graphitic shell with a variable sp(2)-/sp(3)-carbon ratio, is controllably obtained through sequential annealing treatment (550-1300 °C) of nanodiamond. The formation of sp(2) carbon increases with annealing temperature and the nanodiamond surface is reconstructed from amorphous into a well-ordered, onion-like carbon structure via an intermediate composite structure--a diamond core covered by a defective, curved graphene outer shell. Direct dehydrogenation of propane shows that the sp(2)-/sp(3)-nanocomposite exhibits superior catalytic performance to that of individual nanodiamond and graphitic nanocarbon. The optimum catalytic activity of the diamond/graphene composite depends on the maximum structural defectiveness and high chemical reactivity of the ketone groups. Ketone-type functional groups anchored on the defects/vacancies are active for propene formation; nevertheless, once the oxygen functional groups are desorbed, the defects/vacancies alone might be active sites responsible for the C-H bond activation of propane. PMID:24740731

  4. Facile construction of vertically aligned EuS-ZnO hybrid core shell nanorod arrays for visible light driven photocatalytic properties

    SciTech Connect

    Ranjith, K. S.; Kumar, D. Ranjith; Kumar, R. T. Rajendra

    2015-06-24

    We demonstrated the development of coupled semiconductor in the form of hybrid heterostructures for significant advancement in catalytic functional materials. In this article, we report the preparation of vertically aligned core shell ZnO-EuS nanorod photocatalyst arrays by a simple chemical solution process followed by sulfudation process. The XRD pattern confirmed formation of the hexagonal wurtzite structure of ZnO and cubic nature of the EuS. Cross sectional FESEM images show vertical rod array structure, and the size of the nanorods ranges from 80 to 120 nm. UV-Vis DRS spectra showed that the optical absorption of ZnO was significantly enhanced to the visible region by modification with EuS surfaces. TEM study confirmed that the surface of ZnO was drastically improved by the modification with EuS nanoparticle. The catalytic activity of EuS−ZnO core shell nanorod arrays were evaluated by the photodegradation of Methylene Blue (MB) dye under visible irradiation. The results revealed that the photocatalytic activity of EuS−ZnO was much higher than that of ZnO under natural sunlight. EuS−ZnO was found to be stable and reusable without appreciable loss of catalytic activity up to four consecutive cycles.

  5. Metal-Organic Frameworks Derived Porous Core/Shell Structured ZnO/ZnCo2O4/C Hybrids as Anodes for High-Performance Lithium-Ion Battery.

    PubMed

    Ge, Xiaoli; Li, Zhaoqiang; Wang, Chengxiang; Yin, Longwei

    2015-12-01

    Metal-organic frameworks (MOFs) derived porous core/shell ZnO/ZnCo2O4/C hybrids with ZnO as a core and ZnCo2O4 as a shell are for the first time fabricated by using core/shell ZnCo-MOF precursors as reactant templates. The unique MOFs-derived core/shell structured ZnO/ZnCo2O4/C hybrids are assembled from nanoparticles of ZnO and ZnCo2O4, with homogeneous carbon layers coated on the surface of the ZnCo2O4 shell. When acting as anode materials for lithium-ion batteries (LIBs), the MOFs-derived porous ZnO/ZnCo2O4/C anodes exhibit outstanding cycling stability, high Coulombic efficiency, and remarkable rate capability. The excellent electrochemical performance of the ZnO/ZnCo2O4/C LIB anodes can be attributed to the synergistic effect of the porous structure of the MOFs-derived core/shell ZnO/ZnCo2O4/C and homogeneous carbon layer coating on the surface of the ZnCo2O4 shells. The hierarchically porous core/shell structure offers abundant active sites, enhances the electrode/electrolyte contact area, provides abundant channels for electrolyte penetration, and also alleviates the structure decomposition induced by Li(+) insertion/extraction. The carbon layers effectively improve the conductivity of the hybrids and thus enhance the electron transfer rate, efficiently prevent ZnCo2O4 from aggregation and disintegration, and partially buffer the stress induced by the volume change during cycles. This strategy may shed light on designing new MOF-based hybrid electrodes for energy storage and conversion devices. PMID:26572922

  6. Facile Synthesis of Nb2O5@Carbon Core-Shell Nanocrystals with Controlled Crystalline Structure for High-Power Anodes in Hybrid Supercapacitors.

    PubMed

    Lim, Eunho; Jo, Changshin; Kim, Haegyeom; Kim, Mok-Hwa; Mun, Yeongdong; Chun, Jinyoung; Ye, Youngjin; Hwang, Jongkook; Ha, Kyoung-Su; Roh, Kwang Chul; Kang, Kisuk; Yoon, Songhun; Lee, Jinwoo

    2015-07-28

    Hybrid supercapacitors (battery-supercapacitor hybrid devices, HSCs) deliver high energy within seconds (excellent rate capability) with stable cyclability. One of the key limitations in developing high-performance HSCs is imbalance in power capability between the sluggish Faradaic lithium-intercalation anode and rapid non-Faradaic capacitive cathode. To solve this problem, we synthesize Nb2O5@carbon core-shell nanocyrstals (Nb2O5@C NCs) as high-power anode materials with controlled crystalline phases (orthorhombic (T) and pseudohexagonal (TT)) via a facile one-pot synthesis method based on a water-in-oil microemulsion system. The synthesis of ideal T-Nb2O5 for fast Li(+) diffusion is simply achieved by controlling the microemulsion parameter (e.g., pH control). The T-Nb2O5@C NCs shows a reversible specific capacity of ∼180 mA h g(-1) at 0.05 A g(-1) (1.1-3.0 V vs Li/Li(+)) with rapid rate capability compared to that of TT-Nb2O5@C and carbon shell-free Nb2O5 NCs, mainly due to synergistic effects of (i) the structural merit of T-Nb2O5 and (ii) the conductive carbon shell for high electron mobility. The highest energy (∼63 W h kg(-1)) and power (16 528 W kg(-1) achieved at ∼5 W h kg(-1)) densities within the voltage range of 1.0-3.5 V of the HSC using T-Nb2O5@C anode and MSP-20 cathode are remarkable. PMID:26095456

  7. Directly-Grown Hierarchical Carbon Nanotube@Polypyrrole Core-Shell Hybrid for High-Performance Flexible Supercapacitors.

    PubMed

    Yesi, Yesi; Shown, Indrajit; Ganguly, Abhijit; Ngo, Trung Truc; Chen, Li-Chyong; Chen, Kuei-Hsien

    2016-02-19

    A hierarchical carbon nanotube-polypyrrole (CNT-PPy) core-shell composite was fabricated by growing CNTs directly on carbon cloth (CC) as a skeleton followed by electropolymerization of PPy with controlled polymerization time. Direct fabrication of electroactive (CNT-PPy) materials on the flexible CC electrode could reduce the interfacial resistance between the electrode and electrolyte and improve the ion diffusion. The supercapacitor electrode based on optimized PPy/CNT-CC exhibits excellent electrochemical performance, with the highest gravimetric capacitance being roughly 1038 F g(-1) per active mass of PPy and up to 486.1 F g(-1) per active mass of the PPy/CNT composite. Notably, excellent flexibility and cycle stability up to 10 000 cycles with only 18 % capacitance loss was achieved. At the same time, the fabricated asymmetric supercapacitor (PPy/CNT-CC∥CNT-CC) shows the maximum power density of 10 962 W kg(-1) at an energy density of 3.9 Wh kg(-1) under the operating potential of 1.4 V. The overall high cycle stability and high performance of the fabricated PPy/CNT-CC flexible electrode is due to the novel binder-free direct growth process. PMID:26791424

  8. Preliminary evaluation of a 99mTc labeled hybrid nanoparticle bearing a cobalt ferrite core: in vivo biodistribution.

    PubMed

    Psimadas, Dimitrios; Baldi, Giovanni; Ravagli, Costanza; Bouziotis, Penelope; Xanthopoulos, Stavros; Franchini, Mauro Comes; Georgoulias, Panagiotis; Loudos, George

    2012-08-01

    Magnetic nanoparticles have become important tools for imaging a wide range of diseases, improving drug delivery and applying hyperthermic treatment. Iron oxide based nanoparticles have been widely examined, unlike cobalt ferrite based ones. Herein, monodisperse and stable CoFe2O4 nanoparticles have been produced, coated and further stabilized using ethyl 12-(hydroxyamino)-12-oxododecanoate, poly(lactic-co-glycolic acid) and bovine serum albumin. The final product, NBRh1, was fully characterized and has been directly radiolabeled with 99mTc using SnCl1 as the reducing agent in high yields. In vitro stability and hyperthermic properties of 99mTC-NBRh1 were encouraging for further application in low frequencies hyperthermia and biomagnetic applications. In vivo evaluation followed after injection in healthy mice. The planar and SPECT imaging data as well as the biodistribution results were in accordance, showing high liver and spleen uptake as expected starting almost immediately after administration. In conclusion the preliminary results for nanoparticles bearing a cobalt ferrite core justify further investigations towards potential hyperthermic applications, drug transportation and liver or spleen imaging. PMID:22852467

  9. Large-scale fabrication and application of magnetite coated Ag NW-core water-dispersible hybrid nanomaterials.

    PubMed

    Wang, Baoyu; Zhang, Min; Li, Weizhen; Wang, Linlin; Zheng, Jing; Gan, Wenjun; Xu, Jingli

    2015-05-01

    In this work, we report a large scale synthetic procedure that allows attachment of magnetite nanoparticles onto Ag NWs in situ, which was conducted in a triethylene glycol (TREG) solution with iron acetylacetonate and Ag NWs as starting materials. The as-prepared Ag NW/Fe3O4 NP composites are well characterized by SEM, TEM, XRD, XPS, FT-IR, and VSM techniques. It was found that the mass ratio of iron acetylacetonate to Ag NWs plays a crucial role in controlling the amount of magnetite nanoparticles decorated on the Ag NWs. The resulting Ag NW/Fe3O4 NP composites exhibit superparamagnetic properties at room temperature, and can be well dispersed in aqueous and organic solutions, which is greatly beneficial for their application and functionality. Thus, the as-prepared magnetic silver nanowires show good catalytic activity, using the catalytic reduction of methylene blue (MB) as a model reaction. Furthermore, the Ag NW/Fe3O4 NP composites can be functionalized with polydopamine (Pdop), resorcinol-formaldehyde resin (PFR), and SiO2, respectively, in aqueous/ethanol solution. Meanwhile they can also be coated with polyphosphazene (PZS) in organic solution, resulting in a unique nanocable with well-defined core shell structures. Besides, taking Ag NW/Fe3O4@SiO2 as an example, a hollow magnetic silica nanotube can be obtained with the use of Ag NWs as physical templates and a solution of ammonium and H2O2. These can greatly improve the application of the Ag NW/Fe3O4 NP composites. The as-synthesized above nanocomposites have high potential for applications in the fields of polymers, wastewater treatment, sensors, and biomaterials. PMID:25815705

  10. Tunable light emission by exciplex state formation between hybrid halide perovskite and core/shell quantum dots: Implications in advanced LEDs and photovoltaics.

    PubMed

    Sanchez, Rafael S; de la Fuente, Mauricio Solis; Suarez, Isaac; Muñoz-Matutano, Guillermo; Martinez-Pastor, Juan P; Mora-Sero, Ivan

    2016-01-01

    We report the first observation of exciplex state electroluminescence due to carrier injection between the hybrid lead halide perovskite (MAPbI3-xClx) and quantum dots (core/shell PbS/CdS). Single layers of perovskite (PS) and quantum dots (QDs) have been produced by solution processing methods, and their photoluminescent properties are compared to those of bilayer samples in both PS/QD and QD/PS configurations. Exciplex emission at lower energies than the band gap of both PS and QD has been detected. The exciplex emission wavelength of this mixed system can be simply tuned by controlling the QD size. Light-emitting diodes (LEDs) have been fabricated using those configurations, which provide light emission with considerably low turn-on potential. The "color" of the LED can also be tuned by controlling the applied bias. The presence of the exciplex state PS and QDs opens up a broad range of possibilities with important implications not only in tunable LEDs but also in the preparation of intermediate band gap photovoltaic devices with the potentiality of surpassing the Shockley-Queisser limit. PMID:26844299

  11. Tunable light emission by exciplex state formation between hybrid halide perovskite and core/shell quantum dots: Implications in advanced LEDs and photovoltaics

    PubMed Central

    Sanchez, Rafael S.; de la Fuente, Mauricio Solis; Suarez, Isaac; Muñoz-Matutano, Guillermo; Martinez-Pastor, Juan P.; Mora-Sero, Ivan

    2016-01-01

    We report the first observation of exciplex state electroluminescence due to carrier injection between the hybrid lead halide perovskite (MAPbI3–xClx) and quantum dots (core/shell PbS/CdS). Single layers of perovskite (PS) and quantum dots (QDs) have been produced by solution processing methods, and their photoluminescent properties are compared to those of bilayer samples in both PS/QD and QD/PS configurations. Exciplex emission at lower energies than the band gap of both PS and QD has been detected. The exciplex emission wavelength of this mixed system can be simply tuned by controlling the QD size. Light-emitting diodes (LEDs) have been fabricated using those configurations, which provide light emission with considerably low turn-on potential. The “color” of the LED can also be tuned by controlling the applied bias. The presence of the exciplex state PS and QDs opens up a broad range of possibilities with important implications not only in tunable LEDs but also in the preparation of intermediate band gap photovoltaic devices with the potentiality of surpassing the Shockley-Queisser limit. PMID:26844299

  12. Highly selective fluorescent chemosensor for Zn2+ derived from inorganic-organic hybrid magnetic core/shell Fe3O4@SiO2 nanoparticles

    PubMed Central

    2012-01-01

    Magnetic nanoparticles with attractive optical properties have been proposed for applications in such areas as separation and magnetic resonance imaging. In this paper, a simple and novel fluorescent sensor of Zn2+ was designed with 3,5-di-tert-butyl-2-hydroxybenzaldehyde [DTH] covalently grafted onto the surface of magnetic core/shell Fe3O4@SiO2 nanoparticles [NPs] (DTH-Fe3O4@SiO2 NPs) using the silanol hydrolysis approach. The DTH-Fe3O4@SiO2 inorganic-organic hybrid material was characterized by transmission electron microscopy, dynamic light scattering, X-ray power diffraction, diffuse reflectance infrared Fourier transform, UV-visible absorption and emission spectrometry. The compound DTH exhibited fluorescence response towards Zn2+ and Mg2+ ions, but the DTH-Fe3O4@SiO2 NPs only effectively recognized Zn2+ ion by significant fluorescent enhancement in the presence of various ions, which is due to the restriction of the N-C rotation of DTH-Fe3O4@SiO2 NPs and the formation of the rigid plane with conjugation when the DTH-Fe3O4@SiO2 is coordinated with Zn2+. Moreover, this DTH-Fe3O4@SiO2 fluorescent chemosensor also displayed superparamagnetic properties, and thus, it can be recycled by magnetic attraction. PMID:22277075

  13. Core-shell hybrid liposomal vesicles loaded with panax notoginsenoside: preparation, characterization and protective effects on global cerebral ischemia/reperfusion injury and acute myocardial ischemia in rats

    PubMed Central

    Zhang, Jing; Han, Xizhen; Li, Xiang; Luo, Yun; Zhao, Haiping; Yang, Ming; Ni, Bin; Liao, Zhenggen

    2012-01-01

    Purpose: Novel panax notoginsenoside-loaded core-shell hybrid liposomal vesicles (PNS-HLV) were developed to resolve the restricted bioavailability of PNS and to enhance its protective effects in vivo on oral administration. Methods: Physicochemical characterizations of PNS-HLV included assessment of morphology, particle size and zeta potential, encapsulation efficiency (EE%), stability and in vitro release study. In addition, to evaluate its oral treatment potential, we compared the effect of PNS-HLV on global cerebral ischemia/reperfusion and acute myocardial ischemia injury with those of PNS solution, conventional PNS-loaded nanoparticles, and liposomes. Results: In comparison with PNS solution, conventional PNS-loaded nanoparticles and liposomes, PNS-HLV was stable for at least 12 months at 4°C. Satisfactory improvements in the EE% of notoginsenoside R1, ginsenoside Rb1, and ginsenoside Rg1 were shown with the differences in EE% shortened and the greater controlled drug release profiles were exhibited from PNS-HLV. The improvements in the physicochemical properties of HLV contributed to the results that PNS-HLV was able to significantly inhibit the edema of brain and reduce the infarct volume, while it could markedly inhibit H2O2, modified Dixon agar, and serum lactate dehydrogenase, and increase superoxide dismutase (P < 0.05). Conclusion: The results of the present study imply that HLV has promising prospects for improving free drug bioactivity on oral administration. PMID:22915851

  14. Preparation of graphene quantum dots based core-satellite hybrid spheres and their use as the ratiometric fluorescence probe for visual determination of mercury(II) ions.

    PubMed

    Hua, Mengjuan; Wang, Chengquan; Qian, Jing; Wang, Kan; Yang, Zhenting; Liu, Qian; Mao, Hanping; Wang, Kun

    2015-08-12

    We herein proposed a simple and effective strategy for preparing graphene quantum dots (GQDs)-based core-satellite hybrid spheres and further explored the feasibility of using such spheres as the ratiometric fluorescence probe for the visual determination of Hg(2+). The red-emitting CdTe QDs were firstly entrapped in the silica nanosphere to reduce their toxicity and improve their photo and chemical stabilities, thus providing a built-in correction for environmental effects, while the GQDs possessing good biocompatibility and low toxicity were electrostatic self-assembly on the silica surface acting as reaction sites. Upon exposure to the increasing contents of Hg(2+), the blue fluorescence of GQDs can be gradually quenched presumably due to facilitating nonradiative electron/hole recombination annihilation. With the embedded CdTe QDs as the internal standard, the variations of the tested solution display continuous fluorescence color changes from blue to red, which can be easily observed by the naked eye without any sophisticated instrumentations and specially equipped laboratories. This sensor exhibits high sensitivity and selectivity toward Hg(2+) in a broad linear range of 10 nM-22 μM with a low detection limit of 3.3 nM (S/N = 3), much lower than the allowable Hg(2+) contents in drinking water set by U.S. Environmental Protection Agency. This prototype ratiometric probe is of good simplicity, low toxicity, excellent stabilities, and thus potentially attractive for Hg(2+) quantification related biological systems. PMID:26320973

  15. Magnetic core-shell CuFe2O4@C3N4 hybrids for visible light photocatalysis of Orange II.

    PubMed

    Yao, Yunjin; Lu, Fang; Zhu, Yanping; Wei, Fengyu; Liu, Xueting; Lian, Chao; Wang, Shaobin

    2015-10-30

    Novel CuFe2O4@C3N4 core-shell photocatalysts were fabricated through a self-assembly method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, transmission electron microscopy and Uv-vis diffuse reflection spectroscopy. The photocatalytic performances of the CuFe2O4@C3N4 catalysts were evaluated in photo Fenton-like discoloration of Orange II dye using H2O2 as an oxidant under visible-light irradiation (λ>420 nm). It was found the CuFe2O4@C3N4 hybrid (mass ratio of CuFe2O4/g-C3N4 at 2:1) exhibits a superior activity as compared with single component of CuFe2O4 or g-C3N4 and the mixture of g-C3N4 and CuFe2O4, due to the elevation of the separation efficiency of photoinduced electron-hole pairs, resulted from the heterojunction between the interfaces of g-C3N4 and CuFe2O4. The quenching tests of different scavengers displayed that O2(•-), OH and h(+) are responsible for the Orange II decolorization. In addition, the effects of initial concentration of the dye contaminant (0.014-0.140 mM), different anions (Cl(-), SO4(2-), NO3(-), CH3COO(-) and HCO3(-)) and temperature (15-65 °C) in photoreaction were also investigated. The CuFe2O4@C3N4 sample exhibited stable performance without obvious loss of catalytic activity after five successive runs, showing a promising application for the photo-oxidative degradation of environmental contaminants. PMID:25974659

  16. Effect of cyclical thermal to mechanical properties of Hybrid Laminate Composites (HLC) with skin recycle polypropylene/natural fiber/halloysite and core PP/KF composites

    NASA Astrophysics Data System (ADS)

    Sri Suharty, Neng; Ismail, Hanafi; Suci Handayani, Desi; Diharjo, Kuncoro; Rachman Wibowo, Fajar; Arnita Wuri, Margaretha

    2016-02-01

    This research has successfully synthesized six hybrid laminate composites (HLC). These HLC consist of two layers skin composites and one layer of core PP/KF composites. There are sticked with epoxy adhesive by using cold press method. In this research 6 types of skin are used, namely the rPP (recycled polypropylene, HC1); rPP/DVB/PP-g-AA/KF (HC2); rPP/DVB/PP-g-AA/Hall (HC3); rPP/DVB/PP-g-AA/Hall+ZB (HC4); rPP/DVB/PP-g-AA/KF/Hall (HC5) and rPP/DVB/PP-g-AA/KF/Hall+ZB (HC6) composites. The mechanical properties assessment tensile strength (TS) of various HLC before and after cyclical thermal (CT) was done by ASTM D638. While testing the flame retardant: such as time to ignition (TTI) and burning rate (BR) was done by ASTM D635. Heat stability of HLC can be recognized by conducting the CT treatment. It is to determine the effect of fluctuating heat loads on mechanical properties of HLC materials. The TS result of five HLCs (HC2, HC3, HC4, HC5 and HC6) before CT treatment were higher than HC1 (blank HLC). Those five HLC are also able to increase the TTI and reduce the BR compared to HC1. The CT treatment conditions performed at 45 oC as much as 125 times. After CT treatment, the TS values only slightly decline compared to before CT treatment.

  17. Magnetic and pH dual responsive core-shell hybrid nanogels: a single nano-object for pH-dependent magnetic manipulation, fluorescent pH-sensing, and drug delivery

    SciTech Connect

    Wu, Weitai; Shen, Jing; Gai, Zheng; Hong, Kunlun; Banerjeea, Probal; Zhou, Shuiqin

    2011-01-01

    Remotely optical sensing and drug delivery using an environmentally-guided magnetically-driven hybrid nanogel particle could allow for medical diagnostics and treatment. Such multifunctional hybrid nanogels (<200 nm) were prepared through the first synthesis of magnetic Ni NPs, followed by a moderate growth of fluorescent metallic Ag on the surface of Ni NPs, and then a coverage of a pH-responsive copolymer gel shell of poly(ethylene glycol-co-methacrylic acid) [p(EG-MAA)] onto the Ni-Ag bimetallic NP cores (18 {+-} 5 nm). The introduction of the pH-responsive p(EG-MAA) gel shell onto the magnetic and fluorescent Ni-Ag NPs makes the polymer-bound Ni-Ag NPs responsive to pH over the physiologically important range 5.0-7.4. The hybrid nanogels can adapt to surrounding pH and regulate the sensitivity in response to external magnetic field (such as a small magnet of 0.1 T), resulting in the accumulation of the hybrid nanogels within the duration from hours to a few seconds as the pH value decreases from 7.4 to 5.0. The pH-dependent magnetic response characteristic of the hybrid nanogels were further integrated with the pH change to fluorescent signal transduction and pH-regulated anticancer drug (a model drug 5-fluorouracil) delivery functions. The hybrid nanogels can overcome cellular barriers to enter the intracellular region and light up the mouse melanoma B16F10 cells. The multiple responsive hybrid nanogel that can be manipulated in tandem endogenous and exogenous activation should enhance our ability to address the complexity of biological systems.

  18. Multi-responsive hybrid particles: thermo-, pH-, photo-, and magneto-responsive magnetic hydrogel cores with gold nanorod optical triggers.

    PubMed

    Rittikulsittichai, Supparesk; Kolhatkar, Arati G; Sarangi, Subhasis; Vorontsova, Maria A; Vekilov, Peter G; Brazdeikis, Audrius; Randall Lee, T

    2016-06-01

    The research strategy described in this manuscript harnesses the attractive properties of hydrogels, gold nanorods (Aurods), and magnetic nanoparticles (MNPs) by synthesizing one unique multi-responsive nanostructure. This novel hybrid structure consists of silica-coated magnetic particles encapsulated within a thermo-responsive P(NIPAM-co-AA) hydrogel network on which Aurods are assembled. Furthermore, this research demonstrates that these composite particles respond to several forms of external stimuli (temperature, pH, light, and/or applied magnetic field) owing to their specific architecture. Exposure of the hybrid particles to external stimuli led to a systematic and reversible variation in the hydrodynamic diameter (swelling-deswelling) and thus in the optical properties of the hybrid particles (red-shifting of the plasmon band). Such stimuli-responsive volume changes can be effectively exploited in drug-delivery applications. PMID:27227963

  19. A DNA hybridization detection based on fluorescence resonance energy transfer between dye-doped core-shell silica nanoparticles and gold nanoparticles.

    PubMed

    Gao, Feng; Cui, Peng; Chen, Xiaoxiao; Ye, Qingqing; Li, Maoguo; Wang, Lun

    2011-10-01

    A novel and efficient method to evaluate the DNA hybridization based on a fluorescence resonance energy transfer (FRET) system, with fluorescein isothiocyanate (FITC)-doped fluorescent silica nanoparticles (SiNPs) as donor and gold nanoparticles (AuNPs) as acceptor, has been reported. The strategy for specific DNA sequence detecting is based on DNA hybridization event, which is detected via excitation of SiNPs-oligonucleotide conjugates and energy transfer to AuNPs-oligonucleotide conjugates. The proximity required for FRET arises when the SiNPs-oligonucleotide conjugates hybridize with partly complementary AuNPs-oligonucleotide conjugates, resulting in the fluorescence quenching of donors, SiNPs-oligonucleotide conjugates, and the formation of a weakly fluorescent complex, SiNPs-dsDNA-AuNPs. Upon the addition of the target DNA sequence to SiNPs-dsDNA-AuNPs complex, the fluorescence restores (turn-on). Based on the restored fluorescence, a homogeneous assay for the target DNA is proposed. Our results have shown that the linear range for target DNA detection is 0-35.0 nM with a detection limit (3σ) of 3.0 picomole. Compared with FITC-dsDNA-AuNPs probe system, the sensitivity of the proposed probe system for target DNA detection is increased by a factor of 3.4-fold. PMID:21845282

  20. Facile fabrication of FeN nanoparticles/nitrogen-doped graphene core-shell hybrid and its use as a platform for NADH detection in human blood serum.

    PubMed

    Balamurugan, Jayaraman; Thanh, Tran Duy; Kim, Nam Hoon; Lee, Joong Hee

    2016-09-15

    Herein, we present a novel strategy for the synthesis of an iron nitride nanoparticles-encapsulated nitrogen-doped graphene (FeN NPs/NG) core-shell hierarchical nanostructure to boost the electrochemical performance in a highly sensitive, selective, reproducible, and stable sensing platform for nicotinamide adenine dinucleotide (NADH). This core-shell hierarchical nanostructure provides an excellent conductive network for effective charge transfer and avoids the agglomeration and restacking of NG sheets, which provides better access to the electrode material for NADH oxidation. The FeN NPs/NG core-shell hierarchical nanostructure demonstrates direct and mediatorless responses to NADH oxidation at a low potential. This material displays a high sensitivity of 0.028μA/μMcm(2), a wide linear range from 0.4 to 718μM, and a detection limit of 25nM with a fast response time of less than 3s. The interferences from common interferents, such as glucose, uric acid, dopamine, and ascorbic acid, are negligible. The fabricated sensor was further tested for the determination of NADH in human blood serum. The resulting high sensitivity, excellent selectivity, outstanding stability, and good reproducibility make the proposed FeN NPs/NG core-shell hierarchical nanostructure as a promising candidate for biomedical applications. PMID:27104586

  1. Nanocrystalline p-hydroxyacetanilide (paracetamol) and gold core-shell structure as a model drug deliverable organic-inorganic hybrid nanostructure

    NASA Astrophysics Data System (ADS)

    Das, Subhojit; Paul, Anumita; Chattopadhyay, Arun

    2013-09-01

    We report on the generation of core-shell nanoparticles (NPs) having an organic nanocrystal (NC) core coated with an inorganic metallic shell, being dispersed in aqueous medium. First, NCs of p-hydroxyacetanilide (pHA)--known also as paracetamol--were generated in an aqueous medium. Transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) evidenced the formation of pHA NCs and of their crystalline nature. The NCs were then coated with Au to form pHA@Au core-shell NPs, where the thickness of the Au shell was on the order of nanometers. The formation of Au nanoshell--surrounding pHA NC--was confirmed from its surface plasmon resonance (SPR) band in the UV/Vis spectrum and by TEM measurements. Further, on treatment of the core-shell particles with a solution comprising NaCl and HCl (pH < 3), the Au shell could be dissolved, subsequently releasing pHA molecules. The dissolution of Au shell was marked by a gradual diminishing of its SPR band, while the release of pHA molecules in the solution was confirmed from TEM and FTIR studies. The findings suggest that the core-shell NP could be hypothesized to be a model for encapsulating drug molecules, in their crystalline forms, for slow as well as targeted release.We report on the generation of core-shell nanoparticles (NPs) having an organic nanocrystal (NC) core coated with an inorganic metallic shell, being dispersed in aqueous medium. First, NCs of p-hydroxyacetanilide (pHA)--known also as paracetamol--were generated in an aqueous medium. Transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) evidenced the formation of pHA NCs and of their crystalline nature. The NCs were then coated with Au to form pHA@Au core-shell NPs, where the thickness of the Au shell was on the order of nanometers. The formation of Au nanoshell--surrounding pHA NC--was confirmed from its surface plasmon resonance (SPR) band in the UV/Vis spectrum and by TEM measurements. Further, on treatment of the core

  2. Voltage-induced electroluminescence characteristics of hybrid light-emitting diodes with CdSe/Cd/ZnS core-shell nanoparticles embedded in a conducting polymer on plastic substrates

    SciTech Connect

    Kwak, Kiyeol; Cho, Kyoungah E-mail: sangsig@korea.ac.kr; Kim, Sangsig E-mail: sangsig@korea.ac.kr

    2014-03-10

    We investigate the electroluminescence (EL) characteristics of a hybrid light-emitting diode (HyLED) with an emissive layer comprised of CdSe/Cd/ZnS core-shell nanoparticles (NPs) embedded in poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) on a plastic substrate. The EL characteristics change dramatically with increasing of the biased voltage. At low voltages, recombination of electrons and holes occurs only in the PFO film because of poor charge transfer in the PFO-CdSe/Cd/ZnS NPs composite film, while the color of the light-emitting from the HyLED changes from blue to red as the biased voltage increases from 7.5 to 17.5 V. We examine and discuss the mechanism of this color tunability.

  3. Enhanced neo-classical resistivity due to the m/n = 1/1 MHD-mode deformation of the central core plasma column for the tokamak hybrid scenario

    NASA Astrophysics Data System (ADS)

    Takizuka, T.

    2014-09-01

    The tokamak hybrid scenario, a combination of the inductive current drive and the non-inductive current drive, aims at high neutron fluence and a long pulse length for the ITER engineering test towards DEMO. It has been reported experimentally that the concentration of current density, J, peculiar to inductive discharges, was much smaller than that of a simple estimation. We propose a new model to explain the above observations: the central core plasma column can be non-axisymmetric due to the m/n = 1/1 MHD-mode deformation (m and n are poloidal and toroidal mode numbers, respectively). The neo-classical resistivity is enhanced, and the diagnostics are affected. An internal kink mode is a candidate of this instability. Compared with the JT-60U experiment, the reconstructed J profile agrees well with the calculated J profile including the enhanced neo-classical resistivity.

  4. Synthesis and structure-activity relationships of novel hybrid ferrocenyl compounds based on a bicyclic core skeleton for breast cancer therapy.

    PubMed

    Li, Changhao; Tang, Chu; Hu, Zhiye; Zhao, Chenxi; Li, Chenlu; Zhang, Silong; Dong, Chune; Zhou, Hai-Bing; Huang, Jian

    2016-07-01

    Breast cancer is the most frequent cancer in women worldwide, and incidence is increasing year by year. Although current selective estrogen receptor modulators (SERMs) have clear advantages in the treatment of hormone-responsive breast cancer, they are ineffective for ER(-). In this study, we describe the design and synthesis of a series of dual-acting estrogen receptor (ER) and histone deacetylase (HDAC) inhibitors with incorporation of the ferrocenyl moiety, leading to novel hybrid ferrocenyl complexes (FcOBHS-HDACis) for breast cancer therapy. It is worth to note that these ferrocenyl conjugates could not only potently inhibit HDACs and the proliferation of ERα positive (ER(+)) breast cancer cells (MCF-7), but also show significant antiproliferative effect on ER(-) breast cancer cells (MDA-MB-231). Thus, the FcOBHS-HDACi conjugates represent a novel approach to the development of efficiently dual-acting agents for treatment of breast cancer. PMID:27240467

  5. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-01

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo.Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron

  6. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-01

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo.Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron

  7. Hybrid particles and associated methods

    DOEpatents

    Fox, Robert V; Rodriguez, Rene; Pak, Joshua J; Sun, Chivin

    2015-02-10

    Hybrid particles that comprise a coating surrounding a chalcopyrite material, the coating comprising a metal, a semiconductive material, or a polymer; a core comprising a chalcopyrite material and a shell comprising a functionalized chalcopyrite material, the shell enveloping the core; or a reaction product of a chalcopyrite material and at least one of a reagent, heat, and radiation. Methods of forming the hybrid particles are also disclosed.

  8. Core-shell hybrid upconversion nanoparticles carrying stable nitroxide radicals as potential multifunctional nanoprobes for upconversion luminescence and magnetic resonance dual-modality imaging.

    PubMed

    Chen, Chuan; Kang, Ning; Xu, Ting; Wang, Dong; Ren, Lei; Guo, Xiangqun

    2015-03-12

    Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and its derivatives, have recently been used as contrast agents for magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI). However, their rapid one-electron bioreduction to diamagnetic N-hydroxy species when administered intravenously has limited their use in in vivo applications. In this article, a new approach of silica coating for carrying stable radicals was proposed. A 4-carboxyl-TEMPO nitroxide radical was covalently linked with 3-aminopropyl-trimethoxysilane to produce a silanizing TEMPO radical. Utilizing a facile reaction based on the copolymerization of silanizing TEMPO radicals with tetraethyl orthosilicate in reverse microemulsion, a TEMPO radicals doped SiO2 nanostructure was synthesized and coated on the surface of NaYF4:Yb,Er/NaYF4 upconversion nanoparticles (UCNPs) to generate a novel multifunctional nanoprobe, PEGylated UCNP@TEMPO@SiO2 for upconversion luminescence (UCL) and magnetic resonance dual-modality imaging. The electron spin resonance (ESR) signals generated by the TEMPO@SiO2 show an enhanced reduction resistance property for a period of time of up to 1 h, even in the presence of 5 mM ascorbic acid. The longitudinal relaxivity of PEGylated UCNPs@TEMPO@SiO2 nanocomposites is about 10 times stronger than that for free TEMPO radicals. The core-shell NaYF4:Yb,Er/NaYF4 UCNPs synthesized by this modified user-friendly one-pot solvothermal strategy show a significant enhancement of UCL emission of up to 60 times more than the core NaYF4:Yb,Er. Furthermore, the PEGylated UCNP@TEMPO@SiO2 nanocomposites were further used as multifunctional nanoprobes to explore their performance in the UCL imaging of living cells and T1-weighted MRI in vitro and in vivo. PMID:25716884

  9. Composite Cores

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Spang & Company's new configuration of converter transformer cores is a composite of gapped and ungapped cores assembled together in concentric relationship. The net effect of the composite design is to combine the protection from saturation offered by the gapped core with the lower magnetizing requirement of the ungapped core. The uncut core functions under normal operating conditions and the cut core takes over during abnormal operation to prevent power surges and their potentially destructive effect on transistors. Principal customers are aerospace and defense manufacturers. Cores also have applicability in commercial products where precise power regulation is required, as in the power supplies for large mainframe computers.

  10. Core percolation on complex networks.

    PubMed

    Liu, Yang-Yu; Csóka, Endre; Zhou, Haijun; Pósfai, Márton

    2012-11-16

    We analytically solve the core percolation problem for complex networks with arbitrary degree distributions. We find that purely scale-free networks have no core for any degree exponents. We show that for undirected networks if core percolation occurs then it is continuous while for directed networks it is discontinuous (and hybrid) if the in- and out-degree distributions differ. We also find that core percolations on undirected and directed networks have completely different critical exponents associated with their critical singularities. PMID:23215509

  11. Core-Shell Vanadium Modified Titania@β-In2S3 Hybrid Nanorod Arrays for Superior Interface Stability and Photochemical Activity.

    PubMed

    Mumtaz, Asad; Mohamed, Norani Muti; Mazhar, Muhammad; Ehsan, Muhammad Ali; Mohamed Saheed, Mohamed Shuaib

    2016-04-13

    Core-shell rutile TiO2@β-In2S3 and modified V-TiO2@β-In2S3 were synthesized to develop bilayer systems to uphold charge transport via an effective and stable interface. Morphological studies revealed that β-In2S3 was deposited homogeneously on V-TiO2 as compared to unmodified TiO2 nanorod arrays. X-ray photoelectron spectroscopy (XPS) and electron energy loss spectrometry studies verified the presence of various oxidation states of vanadium in rutile TiO2 and the vanadium surface was utilized for broadening the charge collection centers in host substrate layer and hole quencher window. Subsequently, X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectra confirmed the rutile phases of TiO2 and modified V-TiO2 along with the phases of crystalline β-In2S3. XPS valence band study explored the interaction of valence band quazi Fermi levels of β-In2S3 with the conduction band quazi Fermi levels of modified V-TiO2 for enhanced charge collection at the interface. Photoelectrochemical studies show that the photocurrent density of V-TiO2@β-In2S3 is 1.42 mA/cm(2) (1.5AM illumination). Also, the frequency window for TiO2 was broadened by the vanadium modification in rutile TiO2 nanorod arrays, and the lifetime of the charge carrier and stability of the interface in V-TiO2@β-In2S3 were enhanced compared to the unmodified TiO2@β-In2S3. These findings highlight the significance of modifications in host substrates and interfaces, which have profound implications on interphase stability, photocatalysis and solar-fuel-based devices. PMID:26852779

  12. Hybrid response surface methodology-genetic algorithm optimization of ultrasound-assisted transesterification of waste oil catalysed by immobilized lipase on mesoporous silica/iron oxide magnetic core-shell nanoparticles.

    PubMed

    Karimi, Mahmoud; Keyhani, Alireza; Akram, Asadolah; Rahman, Masoud; Jenkins, Bryan; Stroeve, Pieter

    2013-01-01

    The production ofbiodiesel by transesterification of waste cooking oil (WCO) to partially substitute petroleum diesel is one of the measures for solving the twin problems of environment pollution and energy demand. An environmentally benign process for the enzymatic transesterification using immobilized lipase has attracted considerable attention for biodiesel production. Here, a superparamagnetic, high surface area substrate for lipase immobilization is evaluated. These immobilization substrates are composed of mesoporous silica/superparamagnetic iron oxide core-shell nanoparticles. The effects of methanol ratio to WCO, lipase concentration, water content and reaction time on the synthesis of biodiesel were analysed by utilizing the response surface methodology (RSM). A quadratic response surface equation for calculating fatty acid methyl ester (FAME) content as the objective function was established based on experimental data obtained in accordance with the central composite design. The RSM-based model was then used as the fitness function for genetic algorithm (GA) to optimize its input space. Hybrid RSM-GA predicted the maximum FAME content (91%) at the optimum level of medium variables: methanol ratio to WCO, 4.34; lipase content, 43.6%; water content, 10.22%; and reaction time, 6h. Moreover, the immobilized lipase could be used for four times without considerable loss of the activity. PMID:24350474

  13. DUBLIN CORE

    EPA Science Inventory

    The Dublin Core is a metadata element set intended to facilitate discovery of electronic resources. It was originally conceived for author-generated descriptions of Web resources, and the Dublin Core has attracted broad ranging international and interdisciplinary support. The cha...

  14. Cold Hybrid Star Properties

    SciTech Connect

    Moshfegh, H. R.; Darehmoradi, M.; Mojarrad, M. Ghazanfari

    2011-10-28

    Properties of neutron stars with quark core are investigated. The equation of state of hadronic matter is calculated using Myers and Swiatecki two nucleon interaction within Thomas-Fermi semiclassical approximation (TF). For quark matter we employ The MIT bag model with constant and density dependent bag parameter. With use of the obtained equation of states we have calculated mass-radius relation of such hybrid stars.

  15. Nuclear hybrid energy infrastructure

    SciTech Connect

    Agarwal, Vivek; Tawfik, Magdy S.

    2015-02-01

    The nuclear hybrid energy concept is becoming a reality for the US energy infrastructure where combinations of the various potential energy sources (nuclear, wind, solar, biomass, and so on) are integrated in a hybrid energy system. This paper focuses on challenges facing a hybrid system with a Small Modular Reactor at its core. The core of the paper will discuss efforts required to develop supervisory control center that collects data, supports decision-making, and serves as an information hub for supervisory control center. Such a center will also be a model for integrating future technologies and controls. In addition, advanced operations research, thermal cycle analysis, energy conversion analysis, control engineering, and human factors engineering will be part of the supervisory control center. Nuclear hybrid energy infrastructure would allow operators to optimize the cost of energy production by providing appropriate means of integrating different energy sources. The data needs to be stored, processed, analyzed, trended, and projected at right time to right operator to integrate different energy sources.

  16. Asymmetric Hybrid Nanoparticles

    SciTech Connect

    Chumanov, George

    2015-11-05

    Hybrid Nanoparticles (AHNs) are rationally-designed multifunctional nanostructures and novel building blocks for the next generation of advanced materials and devices. Nanoscale materials attract considerable interest because of their unusual properties and potential for practical applications. Most of the activity in this field is focused on the synthesis of homogeneous nanoparticles from metals, metal oxides, semiconductors, and polymers. It is well recognized that properties of nanoparticles can be further enhanced if they are made as hybrid structures. This program is concerned with the synthesis, characterization, and application of such hybrid structures termed AHNs. AHNs are composed of a homogeneous core and several caps of different materials deposited on its surface (Fig. 1). Combined properties of the core and the caps as well as new properties that arise from core-cap and cap-cap interactions render AHNs multifunctional. In addition, specific chemical reactivity of the caps enables directional self-assembly of AHNs into complex architectures that are not possible with only spherical nanoparticles.

  17. 24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES FOR A BRASS GATE VALVE BODY MADE ON A CORE BOX, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  18. Flare Hybrids

    NASA Astrophysics Data System (ADS)

    Tomczak, M.; Dubieniecki, P.

    2015-12-01

    On the basis of the Solar Maximum Mission observations, Švestka ( Solar Phys. 121, 399, 1989) introduced a new class of flares, the so-called flare hybrids. When they start, they look like typical compact flares (phase 1), but later on, they look like flares with arcades of magnetic loops (phase 2). We summarize the characteristic features of flare hybrids in soft and hard X-rays as well as in the extreme ultraviolet; these features allow us to distinguish flare hybrids from other flares. In this article, additional energy release or long plasma cooling timescales are suggested as possible causes of phase 2. We estimate the frequency of flare hybrids, and study the magnetic configurations favorable for flare hybrid occurrence. Flare hybrids appear to be quite frequent, and the difference between the lengths of magnetic loops in the two interacting loop systems seem to be a crucial parameter for determining their characteristics.

  19. Core strengthening.

    PubMed

    Arendt, Elizabeth A

    2007-01-01

    Several recent studies have evaluated interventional techniques designed to reduce the risk of serious knee injuries, particularly noncontact anterior cruciate ligament injuries in female athletes. Maintenance of rotational control of the limb underneath the pelvis, especially in response to cutting and jumping activities, is a common goal in many training programs. Rotational control of the limb underneath the pelvis is mediated by a complex set of factors including the strength of the trunk muscles and the relationship between the core muscles. It is important to examine the interrelationship between lower extremity function and core stability. PMID:17472321

  20. Stellarator hybrids

    SciTech Connect

    Furth, H.P.; Ludescher, C.

    1984-08-01

    The present paper briefly reviews the subject of tokamak-stellarator and pinch-stellarator hybrids, and points to two interesting new possibilities: compact-torus-stellarators and mirror-stellarators.

  1. Hybrid Inflatable Pressure Vessel

    NASA Technical Reports Server (NTRS)

    Raboin, Jasen; Valle, Gerard D.; Edeen, Gregg; DeLaFuente, Horacio M.; Schneider, William C.; Spexarth, Gary R.; Johnson, Christopher J.; Pandya, Shalini

    2004-01-01

    Figure 1 shows a prototype of a large pressure vessel under development for eventual use as a habitable module for long spaceflight (e.g., for transporting humans to Mars). The vessel is a hybrid that comprises an inflatable shell attached to a rigid central structural core. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a web of straps made from high-strength polymeric fabrics. On Earth, pressure vessels like this could be used, for example, as portable habitats that could be set up quickly in remote locations, portable hyperbaric chambers for treatment of decompression sickness, or flotation devices for offshore platforms. In addition, some aspects of the design of the fabric straps could be adapted to such other items as lifting straps, parachute straps, and automotive safety belts. Figure 2 depicts selected aspects of the design of a vessel of this type with a toroidal configuration. The bladder serves as an impermeable layer to keep air within the pressure vessel and, for this purpose, is sealed to the central structural core. The web includes longitudinal and circumferential straps. To help maintain the proper shape upon inflation after storage, longitudinal and circumferential straps are indexed together at several of their intersections. Because the web is not required to provide a pressure seal and the bladder is not required to sustain structural loads, the bladder and the web can be optimized for their respective functions. Thus, the bladder can be sealed directly to the rigid core without having to include the web in the seal substructure, and the web can be designed for strength. The ends of the longitudinal straps are attached to the ends of the rigid structural core by means of clevises. Each clevis pin is surrounded by a roller, around which a longitudinal strap is wrapped to form a lap seam with itself. The roller is of a large diameter chosen to reduce bending of the fibers in

  2. Silicon nanocrystal-noble metal hybrid nanoparticles.

    PubMed

    Sugimoto, H; Fujii, M; Imakita, K

    2016-06-01

    We report a novel and facile self-limiting synthesis route of silicon nanocrystal (Si NC)-based colloidally stable semiconductor-metal (gold, silver and platinum) hybrid nanoparticles (NPs). For the formation of hybrid NPs, we employ ligand-free colloidal Si NCs with heavily boron (B) and phosphorus (P) doped shells. By simply mixing B and P codoped colloidal Si NCs with metal salts, hybrid NPs consisting of metal cores and Si NC shells are spontaneously formed. We demonstrate the synthesis of highly uniform and size controllable hybrid NPs. It is shown that codoped Si NCs act as a reducing agent for metal salts and also as a protecting layer to stop metal NP growth. The process is thus self-limiting. The development of a variety of Si NC-based hybrid NPs is a promising first step for the design of biocompatible multifunctional NPs with broad material choices for biosensing, bioimaging and solar energy conversion. PMID:27121127

  3. Growth outside the core.

    PubMed

    Zook, Chris; Allen, James

    2003-12-01

    Growth in an adjacent market is tougher than it looks; three-quarters of the time, the effort fails. But companies can change those odds dramatically. Results from a five-year study of corporate growth conducted by Bain & Company reveal that adjacency expansion succeeds only when built around strong core businesses that have the potential to become market leaders. And the best place to look for adjacency opportunities is inside a company's strongest customers. The study also found that the most successful companies were able to consistently, profitably outgrow their rivals by developing a formula for pushing out the boundaries of their core businesses in predictable, repeatable ways. Companies use their repeatability formulas to expand into any number of adjacencies. Some companies make repeated geographic moves, as Vodafone has done in expanding from one geographic market to another over the past 13 years, building revenues from $1 billion in 1990 to $48 billion in 2003. Others apply a superior business model to new segments. Dell, for example, has repeatedly adapted its direct-to-customer model to new customer segments and new product categories. In other cases, companies develop hybrid approaches. Nike executed a series of different types of adjacency moves: it expanded into adjacent customer segments, introduced new products, developed new distribution channels, and then moved into adjacent geographic markets. The successful repeaters in the study had two common characteristics. First, they were extraordinarily disciplined, applying rigorous screens before they made an adjacency move. This discipline paid off in the form of learning curve benefits, increased speed, and lower complexity. And second, in almost all cases, they developed their repeatable formulas by studying their customers and their customers' economics very, very carefully. PMID:14712545

  4. Hybrid microelectronic technology

    NASA Astrophysics Data System (ADS)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  5. Dual-core antiresonant hollow core fibers.

    PubMed

    Liu, Xuesong; Fan, Zhongwei; Shi, Zhaohui; Ma, Yunfeng; Yu, Jin; Zhang, Jing

    2016-07-25

    In this work, dual-core antiresonant hollow core fibers (AR-HCFs) are numerically demonstrated, based on our knowledge, for the first time. Two fiber structures are proposed. One is a composite of two single-core nested nodeless AR-HCFs, exhibiting low confinement loss and a circular mode profile in each core. The other has a relatively simple structure, with a whole elliptical outer jacket, presenting a uniform and wide transmission band. The modal couplings of the dual-core AR-HCFs rely on a unique mechanism that transfers power through the air. The core separation and the gap between the two cores influence the modal coupling strength. With proper designs, both of the dual-core fibers can have low phase birefringence and short modal coupling lengths of several centimeters. PMID:27464191

  6. High color rendering index white LED based on nano-YAG:Ce3+ phosphor hybrid with CdSe/CdS/ZnS core/shell/shell quantum dots

    NASA Astrophysics Data System (ADS)

    Shen, Changyu; Chu, Jinlei; Qian, Feng; Zou, Xin; Zhong, Chuan; Li, Ke; Jin, Shangzhong

    2012-08-01

    To improve the poor color rendering index (CRI) of YAG:Ce-based white light-emitting diode (LED) due to the lack of red spectral component, core/shell/shell CdSe/CdS/ZnS quantum dots (QDs) were synthesized and blended into nano-YAG:Ce3+ phosphors. Prominent spectral evolution has been achieved by increasing the content of QDs. A white LED combining a blue LED with the blends of nano-YAG phosphors and orange- and red-emission QDs with a weight ratio of 1:1:1 was obtained. This kind of white LED showed excellent white light with luminescent efficiency, color coordinates, CRI and correlated color temperature (CCT) of 82.5 lm/W, (0.3264, 0.3255), 91 and 4580 K, respectively.

  7. Hybrid Gear

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  8. ) Hybrid Composite

    NASA Astrophysics Data System (ADS)

    Show, Bijay Kumar; Mondal, Dipak Kumar; Maity, Joydeep

    2014-12-01

    In this research work, the dry sliding wear behavior of 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite was investigated at low sliding speed (1 m/s) against a hardened EN 31 disk at different loads. In general, the wear mechanism involved adhesion (along with associated subsurface cracking and delamination) and microcutting abrasion at lower load. While at higher load, abrasive wear involving microcutting and microploughing along with adherent oxide formation was observed. The overall wear rate increased with increasing normal load. The massive particle clusters as well as individual reinforcement particles were found to stand tall to resist abrasive wear. Besides, at higher load, the generation of adherent nodular tribo-oxide through nucleation and epitaxial growth on existing Al2O3 particles lowered down the wear rate. Accordingly, at any normal load, 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite exhibited superior wear resistance (lower overall wear rate) than the reported wear resistance of monolithic 6351 Al alloy.

  9. Hybrid Simulator

    Energy Science and Technology Software Center (ESTSC)

    2005-10-15

    HybSim (short for Hybrid Simulator) is a flexible, easy to use screening tool that allows the user to quanti the technical and economic benefits of installing a village hybrid generating system and simulates systems with any combination of —Diesel generator sets —Photovoltaic arrays -Wind Turbines and -Battery energy storage systems Most village systems (or small population sites such as villages, remote military bases, small communities, independent or isolated buildings or centers) depend on diesel generationmore » systems for their source of energy. HybSim allows the user to determine other "sources" of energy that can greatly reduce the dollar to kilo-watt hour ratio. Supported by the DOE, Energy Storage Program, HybSim was initially developed to help analyze the benefits of energy storage systems in Alaskan villages. Soon after its development, other sources of energy were added providing the user with a greater range of analysis opportunities and providing the village with potentially added savings. In addition to village systems, HybSim has generated interest for use from military institutions in energy provisions and USAID for international village analysis.« less

  10. Core-core and core-valence correlation

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1988-01-01

    The effect of (1s) core correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and core correlation, is discussed. When both core-core and core-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.

  11. Hybridized tetraquarks

    NASA Astrophysics Data System (ADS)

    Esposito, A.; Pilloni, A.; Polosa, A. D.

    2016-07-01

    We propose a new interpretation of the neutral and charged X , Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0 π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X , Z particles. Considerations on a state with the same quantum numbers as the X (5568) are also made.

  12. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    SciTech Connect

    Nan, Alexandrina Bunge, Alexander; Turcu, Rodica

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  13. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    NASA Astrophysics Data System (ADS)

    Nan, Alexandrina; Bunge, Alexander; Turcu, Rodica

    2015-12-01

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  14. Coring technologies for scientific drilling projects: an overview

    SciTech Connect

    Rowley, J.C.

    1985-08-01

    This report outlines the well-developed continuous diamond-coring technology of the minerals industry and the deep-spot-coring procedures that have been optimized for petroleum exploration. The coring hardware, procedures, and technology developed for the sea floor sampling by the Deep Sea Drilling Program (DSDP) are presented as an example of a hybrid core drilling system adopted for scientific coring purposes. The important features and limitations of conventional coring technologies are set forth, and the alternate approaches that will optimize core quality and reduce time and costs are illustrated. Surface rotary drives and downhole motor drives are contrasted and compared. The most significant factors of long core bit life and continuous wireline core retrieval are stressed, and their influence on reduction of operating time and costs is indicated. Several types of core bits are illustrated, both those for slim hole mining and those for oil and gas applications, as well as several core bit designs that have been developed for scientific coring projects. Finally, after concepts, applications, and hardware have been considered, drilling strategies are recommended for deep, scientific coring in hard crustal rocks.

  15. Enhanced bioactivity of internally functionalized cationic dendrimers with PEG cores

    PubMed Central

    Albertazzi, Lorenzo; Mickler, Frauke M.; Pavan, Giovanni M.; Salomone, Fabrizio; Bardi, Giuseppe; Panniello, Mariangela; Amir, Elizabeth; Kang, Taegon; Killops, Kato L.; Bräuchle, Christoph; Amir, Roey J.; Hawker, Craig J.

    2012-01-01

    Hybrid dendritic-linear block copolymers based on a 4-arm polyethylene glycol (PEG) core were synthesized using an accelerated AB2/CD2 dendritic growth approach through orthogonal amine/epoxy and thiol-yne chemistries. The biological activity of these 4-arm and the corresponding 2-arm hybrid dendrimers revealed an enhanced, dendritic effect with an exponential increase in cell internalization concomitant with increasing amine end-groups and low cytotoxicity. Furthermore, the ability of these hybrid dendrimers to induce endosomal escape combined with their facile and efficient synthesis makes them attractive platforms for gene transfection. The 4-arm-based dendrimer showed significantly improved DNA binding and gene transfection capabilities in comparison with the 2-arm derivative. These results combined with the MD simulation indicate a significant effect of both the topology of the PEG core and the multivalency of these hybrid macromolecules, on their DNA binding and delivery capablities. PMID:23140570

  16. Nanorice: a new hybrid nanostructure

    NASA Astrophysics Data System (ADS)

    Nordlander, P.; Brandl, D.; Le, F.; Wang, H.; Halas, N. J.

    2006-03-01

    The plasmon hybridization method [1] is applied to nanorice, a new metallic nanostructure which combines the properties of two popular tunable plasmonic nanoparticle geometries: nanorods and nanoshells. The particle consists of a prolate spheroidal dielectric core and a thin metallic shell, bearing a remarkable resemblance to a rice grain. The nanorice particle shows far greater geometric tunability of the optical resonance, larger local field intensity enhancements and far greater sensitivity as a surface plasmon resonance (SPR) nanosensor than any previously reported dielectric-metal nanostructure. The tunability of the nanorice particle arises from the interaction of primitive plasmons associated with the inner and outer surfaces of the shell. The results from plasmon hybridization are compared to FDTD simulations. [1] E. Prodan and P. Nordlander, J. Chem. Phys. 120(2004)5444-5454

  17. Inorganic/polymer hybrid nanoparticles for sensing applications.

    PubMed

    Sierra-Martin, Benjamin; Fernandez-Barbero, Antonio

    2016-07-01

    This paper reviews a wide set of sensing applications based on the special properties associated with inorganic/polymer composite nanoparticles. We first describe optical sensing applications performed with hybrid nanoparticles and hybrid microgels with special emphasis on photoluminescence detection and imaging. Analyte detection with molecularly imprinted polymers and HPLC-based sensing using hybrid nanoparticles as stationary phase is also summarized. The final part is devoted to the study of ultra-sensitive molecule detection by surface-enhanced Raman spectroscopy using core-shell hybrid materials composed of noble metal nanoparticles and cross-linked polymers. PMID:26782148

  18. Academic Rigor: The Core of the Core

    ERIC Educational Resources Information Center

    Brunner, Judy

    2013-01-01

    Some educators see the Common Core State Standards as reason for stress, most recognize the positive possibilities associated with them and are willing to make the professional commitment to implementing them so that academic rigor for all students will increase. But business leaders, parents, and the authors of the Common Core are not the only…

  19. Nanorice Particles: Hybrid Plasmonic Nanostructures

    NASA Technical Reports Server (NTRS)

    Wang, Hui (Inventor); Brandl, Daniel (Inventor); Le, Fei (Inventor); Nordlander, Peter (Inventor); Halas, Nancy J. (Inventor)

    2010-01-01

    A new hybrid nanoparticle, i.e., a nanorice particle, which combines the intense local fields of nanorods with the highly tunable plasmon resonances of nanoshells, is described herein. This geometry possesses far greater structural tunability than previous nanoparticle geometries, along with much larger local field enhancements and far greater sensitivity as a surface plasmon resonance (SPR) nanosensor than presently known dielectric-conductive material nanostructures. In an embodiment, a nanoparticle comprises a prolate spheroid-shaped core having a first aspect ratio. The nanoparticle also comprises at least one conductive shell surrounding said prolate spheroid-shaped core. The nanoparticle has a surface plasmon resonance sensitivity of at least 600 nm RIU(sup.-1). Methods of making the disclosed nanorice particles are also described herein.

  20. Hybrid mimics and hybrid vigor in Arabidopsis

    PubMed Central

    Wang, Li; Greaves, Ian K.; Groszmann, Michael; Wu, Li Min; Dennis, Elizabeth S.; Peacock, W. James

    2015-01-01

    F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics of the F1 hybrid are stabilized. These hybrid mimic lines, like the F1 hybrid, have larger leaves than the parent plant, and the leaves have increased photosynthetic cell numbers, and in some lines, increased size of cells, suggesting an increased supply of photosynthate. A comparison of the differentially expressed genes in the F1 hybrid with those of eight hybrid mimic lines identified metabolic pathways altered in both; these pathways include down-regulation of defense response pathways and altered abiotic response pathways. F6 hybrid mimic lines are mostly homozygous at each locus in the genome and yet retain the large F1-like phenotype. Many alleles in the F6 plants, when they are homozygous, have expression levels different to the level in the parent. We consider this altered expression to be a consequence of transregulation of genes from one parent by genes from the other parent. Transregulation could also arise from epigenetic modifications in the F1. The pure breeding hybrid mimics have been valuable in probing the mechanisms of hybrid vigor and may also prove to be useful hybrid vigor equivalents in agriculture. PMID:26283378

  1. Silicon nanocrystal-noble metal hybrid nanoparticles

    NASA Astrophysics Data System (ADS)

    Sugimoto, H.; Fujii, M.; Imakita, K.

    2016-05-01

    We report a novel and facile self-limiting synthesis route of silicon nanocrystal (Si NC)-based colloidally stable semiconductor-metal (gold, silver and platinum) hybrid nanoparticles (NPs). For the formation of hybrid NPs, we employ ligand-free colloidal Si NCs with heavily boron (B) and phosphorus (P) doped shells. By simply mixing B and P codoped colloidal Si NCs with metal salts, hybrid NPs consisting of metal cores and Si NC shells are spontaneously formed. We demonstrate the synthesis of highly uniform and size controllable hybrid NPs. It is shown that codoped Si NCs act as a reducing agent for metal salts and also as a protecting layer to stop metal NP growth. The process is thus self-limiting. The development of a variety of Si NC-based hybrid NPs is a promising first step for the design of biocompatible multifunctional NPs with broad material choices for biosensing, bioimaging and solar energy conversion.We report a novel and facile self-limiting synthesis route of silicon nanocrystal (Si NC)-based colloidally stable semiconductor-metal (gold, silver and platinum) hybrid nanoparticles (NPs). For the formation of hybrid NPs, we employ ligand-free colloidal Si NCs with heavily boron (B) and phosphorus (P) doped shells. By simply mixing B and P codoped colloidal Si NCs with metal salts, hybrid NPs consisting of metal cores and Si NC shells are spontaneously formed. We demonstrate the synthesis of highly uniform and size controllable hybrid NPs. It is shown that codoped Si NCs act as a reducing agent for metal salts and also as a protecting layer to stop metal NP growth. The process is thus self-limiting. The development of a variety of Si NC-based hybrid NPs is a promising first step for the design of biocompatible multifunctional NPs with broad material choices for biosensing, bioimaging and solar energy conversion. Electronic supplementary information (ESI) available: Additional TEM images and extinction spectra of Si-metal hybrid NPs are shown in Fig. S1

  2. The Core Skills Initiative.

    ERIC Educational Resources Information Center

    Further Education Unit, London (England).

    A British initiative that aims to identify, develop, and assess core skills in post-16 courses and qualifications is summarized in this bulletin. The first section discusses expectations regarding what core skills can achieve. The following section focuses on other purposes to which core skills could contribute, such as broadening the post-16…

  3. Core Competence and Education.

    ERIC Educational Resources Information Center

    Holmes, Gary; Hooper, Nick

    2000-01-01

    Outlines the concept of core competence and applies it to postcompulsory education in the United Kingdom. Adopts an educational perspective that suggests accreditation as the core competence of universities. This economic approach suggests that the market trend toward lifetime learning might best be met by institutions developing a core competence…

  4. Core Design Applications

    Energy Science and Technology Software Center (ESTSC)

    1995-07-12

    CORD-2 is intended for core desigh applications of pressurized water reactors. The main objective was to assemble a core design system which could be used for simple calculations (such as frequently required for fuel management) as well as for accurate calculations (for example, core design after refueling).

  5. Coring Sample Acquisition Tool

    NASA Technical Reports Server (NTRS)

    Haddad, Nicolas E.; Murray, Saben D.; Walkemeyer, Phillip E.; Badescu, Mircea; Sherrit, Stewart; Bao, Xiaoqi; Kriechbaum, Kristopher L.; Richardson, Megan; Klein, Kerry J.

    2012-01-01

    A sample acquisition tool (SAT) has been developed that can be used autonomously to sample drill and capture rock cores. The tool is designed to accommodate core transfer using a sample tube to the IMSAH (integrated Mars sample acquisition and handling) SHEC (sample handling, encapsulation, and containerization) without ever touching the pristine core sample in the transfer process.

  6. Hybrid boosters for future launch vehicles

    NASA Astrophysics Data System (ADS)

    Dargies, E.; Lo, R. E.

    There is a striking similarity in the design of the US Space Transportation System, the European ARI-ANE 5P and the Japanese II-II: they all use a high energy cryogenic core stage along with two large solid propellant rocket boosters (SRB's) in order to provide for a high lift-off thrust level. Prior to last years disasters with Challenger and Titan it was widely held that SRB's were cheap, uncomplicated and safe. Even before the revelation by these accidents of severe safety hazards, shuttle operations demonstrated that the SRB's were by no means as cheap as reusable systems ought to be. In addition, they became known as sources of considerable environmental pollution. In contrast, hybrid rocket propulsion systems offer the following potential advantages: • much higher savety level (TNT equivalent almost zero, shut-down capability in case of ignition failure of one unit, inert against unbonding) • choice of non-toxic propellant combinations • equal or higher specific performance For these reasons, system analysis were carried out to examine hybrids as potential alternative to SRB's. Various analytical tools (mass- and performance models, trajectory simulation etc.) were developed for parametrical studies of hybrid propulsion systems. Special attention was devoted to the well-known primary concern of hybrids: geometrical design of the solid fuel grain and regression rate of the ablating surface. Experimental data were used as input wherever possible. In 1985 first studies were carried out to find possible fields of application for hybrid rocket engines. A mass model and a performance model for hybrid rocket motors were developed, taking into account the peculiarities of hybrid combustion as there are i.e. low regression rate and shifting mixture ratio during operation. After some analytical work was done, hybrids proved to be a promising alternative to SRB's. Compared with solids, hybrids offer many advantages.

  7. Antivirals interacting with hepatitis B virus core protein and core mutations may misdirect capsid assembly in a similar fashion.

    PubMed

    Hacker, Hans Jörg; Deres, Karl; Mildenberger, Maria; Schröder, Claus H

    2003-12-15

    Recently, heteroarylpyrimidines (HAP) have been identified as potent inhibitors of capsid maturation. Here we discuss the HAP mode of action comparing the aggregation phenotype of wild-type and mutant core proteins with the respective phenotype imposed by HAP or other agents interacting with core protein. Pertinent tests include core fusion protein-mediated transactivation in a two-hybrid system and capsid formation. The finding that transactivation appeared to be unaffected by HAP, or by mutations preventing assembly, is surprising and raises the question for the structure of the interacting hybrid core proteins: Are they monomers, dimers or even oligomers? A direct activity of core fusion monomers is not excluded but considered to be highly unlikely due to rapid homodimerisation. A role of core fusion dimers in transactivation would indicate distinct interactions with a differential sensitivity to HAP. Regarding significance of data gained in two-hybrid systems, caution is necessary, since the site of transactivation is the nucleus, whereas the real site of the core protein interactions during replication is the cytoplasm. Apparently, HAP leave the monomer-monomer interface of HBV core protein unaffected but prevent capsid maturation by interacting with a region known to be crucial for dimer multimerisation and formation of stable capsids. It is suggested to use antivirals as tools for the elucidation of early steps in genome replication and capsid assembly. A frame for this could be the hypothesis that the virus uses soluble core protein, namely intracellular maturation intermediates of HbeAg for a core targeted self-restriction of replication. PMID:14637185

  8. Banded transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W. T. (Inventor)

    1974-01-01

    A banded transformer core formed by positioning a pair of mated, similar core halves on a supporting pedestal. The core halves are encircled with a strap, selectively applying tension whereby a compressive force is applied to the core edge for reducing the innate air gap. A dc magnetic field is employed in supporting the core halves during initial phases of the banding operation, while an ac magnetic field subsequently is employed for detecting dimension changes occurring in the air gaps as tension is applied to the strap.

  9. "Snowing" Core in Earth?

    NASA Astrophysics Data System (ADS)

    Li, J.; Chen, B.; Cormier, V.; Gao, L.; Gubbins, D.; Kharlamova, S. A.; He, K.; Yang, H.

    2008-12-01

    As a planet cools, an initially molten core gradually solidifies. Solidification occurs at shallow depths in the form of "snow", if the liquidus temperature gradient of the core composition is smaller than the adiabatic temperature gradient in the core. Experimental data on the melting behavior of iron-sulfur binary system suggest that the cores of Mercury and Ganymede are probably snowing at the present time. The Martian core is predicted to snow in the future, provided that the sulfur content falls into the range of 10 to 14 weight percent. Is the Earth's core snowing? If so, what are the surface manifestations? If the Earth's core snowed in the past, how did it affect the formation of the solid inner core and the geodynamo? Here, we evaluate the likelihood and consequences of a snowing core throughout the Earth's history, on the basis of mineral physics data describing the melting behavior, equation-of-state, and thermodynamic properties of iron-rich alloys at high pressures. We discuss if snowing in the present-day Earth can reproduce the shallow gradients of compressional wave velocity above the inner-core boundary, and whether or not snowing in the early Earth may reconcile the apparent young age of the solid inner core with a long-lived geodynamo.

  10. Continuous coring drill bit

    SciTech Connect

    Ford, G.A.

    1987-09-22

    A continuous coring drill bit is described comprising: (a) body means defining a vertical axis and adapted for connection to drill pipe and forming an internal body cavity disposed in eccentric relation with the vertical axis and a generally circular throat in communication with the body cavity for conducting drilling fluid. The throat defining a throat axis coincident with the vertical axis and being of a configuration permitting passage of a formation core into the body cavity; (b) a generally cylindrical tubular core breaker being rotatably mounted within the body cavity and defining a vertical axis of rotation of generally parallel and offset relation with the vertical axis of the body means; and (c) a buttress element extending inwardly from the core breaker and adapted to contact the formation core. Upon each rotation of the drill bit the buttress element applying transverse force to the core for fracturing of the core into sections sufficiently small for transport by the drilling fluid.

  11. HYDRATE CORE DRILLING TESTS

    SciTech Connect

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate formation comprised of coarse, large

  12. 23. CORE WORKER OPERATING A COREBLOWER THAT PNEUMATICALLY FILLED CORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. CORE WORKER OPERATING A CORE-BLOWER THAT PNEUMATICALLY FILLED CORE BOXES WITH RESIGN IMPREGNATED SAND AND CREATED A CORE THAT THEN REQUIRED BAKING, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  13. Interaction of structural core protein of Classical Swine Fever Virus with endoplasmic reticulum-associated degradation pathway protein OS9

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classical Swine Fever Virus (CSFV) Core protein is involved in virus RNA protection, transcription regulation and virus virulence. To discover additional Core protein functions a yeast two-hybrid system was used to identify host proteins that interact with Core. Among the identified host proteins, t...

  14. Core-Cutoff Tool

    NASA Technical Reports Server (NTRS)

    Gheen, Darrell

    2007-01-01

    A tool makes a cut perpendicular to the cylindrical axis of a core hole at a predetermined depth to free the core at that depth. The tool does not damage the surrounding material from which the core was cut, and it operates within the core-hole kerf. Coring usually begins with use of a hole saw or a hollow cylindrical abrasive cutting tool to make an annular hole that leaves the core (sometimes called the plug ) in place. In this approach to coring as practiced heretofore, the core is removed forcibly in a manner chosen to shear the core, preferably at or near the greatest depth of the core hole. Unfortunately, such forcible removal often damages both the core and the surrounding material (see Figure 1). In an alternative prior approach, especially applicable to toxic or fragile material, a core is formed and freed by means of milling operations that generate much material waste. In contrast, the present tool eliminates the damage associated with the hole-saw approach and reduces the extent of milling operations (and, hence, reduces the waste) associated with the milling approach. The present tool (see Figure 2) includes an inner sleeve and an outer sleeve and resembles the hollow cylindrical tool used to cut the core hole. The sleeves are thin enough that this tool fits within the kerf of the core hole. The inner sleeve is attached to a shaft that, in turn, can be attached to a drill motor or handle for turning the tool. This tool also includes a cutting wire attached to the distal ends of both sleeves. The cutting wire is long enough that with sufficient relative rotation of the inner and outer sleeves, the wire can cut all the way to the center of the core. The tool is inserted in the kerf until its distal end is seated at the full depth. The inner sleeve is then turned. During turning, frictional drag on the outer core pulls the cutting wire into contact with the core. The cutting force of the wire against the core increases with the tension in the wire and

  15. Lunar core: occam's razor?

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Whether or not the earth's moon has a core is a much bandied question. Like many notions about the properties of the moon, ideas of a lunar core changed drastically after the Apollo studies. A review of the development of these ideas was given a scholarly treatment by S.K. Runcorn recently (Nature, 304, 589-596, 1983). In contrast, L.L. Hood, C.P. Sonett, and L.J. Srnka have questioned the concept in serious detail (Nature, 307, 661-662, 1984).Whether or not the moon actually has or has had a fluid metallic core is of great consequence for a number of geophysical theories about the solar system. Most investigators concede that the possible existence of a lunar core remains one of the major unanswered, and yet most critical, questions about the moon. A lot rides on the answer: Can a lunar-sized body have a core? Is the core metallic? How is the core related to lunar magnetism and its paleomagnetism? Is or was a lunar core related to lunar volcanism? If the moon can have a core, is planetary core formation in the solar system a simple matter of gravitationally segregating metallic fragments that were formed elsewhere? Implications of the questions are without limit. There is, perhaps, no more valid issue about the moon to explore scientifically.

  16. Hybrid rocket propulsion

    NASA Technical Reports Server (NTRS)

    Holzman, Allen L.

    1993-01-01

    Topics addressed are: (1) comparison of the theoretical impulses; (2) comparison of the density-specific impulses; (3) general propulsion system features comparison; (4) hybrid systems, booster applications; and (5) hybrid systems, upper stage propulsion applications.

  17. Hybridization and hybrid speciation under global change.

    PubMed

    Vallejo-Marín, Mario; Hiscock, Simon J

    2016-09-01

    Contents 1170 I. 1170 II. 1172 III. 1175 IV. 1180 V. 1183 1184 References 1184 SUMMARY: An unintended consequence of global change is an increase in opportunities for hybridization among previously isolated lineages. Here we illustrate how global change can facilitate the breakdown of reproductive barriers and the formation of hybrids, drawing on the flora of the British Isles for insight. Although global change may ameliorate some of the barriers preventing hybrid establishment, for example by providing new ecological niches for hybrids, it will have limited effects on environment-independent post-zygotic barriers. For example, genic incompatibilities and differences in chromosome numbers and structure within hybrid genomes are unlikely to be affected by global change. We thus speculate that global change will have a larger effect on eroding pre-zygotic barriers (eco-geographical isolation and phenology) than post-zygotic barriers, shifting the relative importance of these two classes of reproductive barriers from what is usually seen in naturally produced hybrids where pre-zygotic barriers are the largest contributors to reproductive isolation. Although the long-term fate of neo-hybrids is still to be determined, the massive impact of global change on the dynamics and distribution of biodiversity generates an unprecedented opportunity to study large numbers of unpredicted, and often replicated, hybridization 'experiments', allowing us to peer into the birth and death of evolutionary lineages. PMID:27214560

  18. From hybrid swarms to swarms of hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The introgression of modern humans (Homo sapiens) with Neanderthals 40,000 YBP after a half-million years of separation, may have led to the best example of a hybrid swarm on earth. Modern trade and transportation in support of the human hybrids has continued to introduce additional species, genotyp...

  19. Mesoscale hybrid calibration artifact

    DOEpatents

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  20. Quinoline-based antimalarial hybrid compounds.

    PubMed

    Vandekerckhove, Stéphanie; D'hooghe, Matthias

    2015-08-15

    Quinoline-containing compounds, such as quinine and chloroquine, have a long-standing history as potent antimalarial agents. However, the increasing resistance of the Plasmodium parasite against these drugs and the lack of licensed malaria vaccines have forced chemists to develop synthetic strategies toward novel biologically active molecules. A strategy that has attracted considerable attention in current medicinal chemistry is based on the conjugation of two biologically active molecules into one hybrid compound. Since quinolines are considered to be privileged antimalarial building blocks, the synthesis of quinoline-containing antimalarial hybrids has been elaborated extensively in recent years. This review provides a literature overview of antimalarial hybrid molecules containing a quinoline core, covering publications between 2009 and 2014. PMID:25593097

  1. Hybrid armature projectile

    DOEpatents

    Hawke, R.S.; Asay, J.R.; Hall, C.A.; Konrad, C.H.; Sauve, G.L.; Shahinpoor, M.; Susoeff, A.R.

    1993-03-02

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasma blowby.

  2. Hybrid armature projectile

    DOEpatents

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.

    1993-01-01

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  3. Homoploid hybrid expectations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homoploid hybrid speciation occurs when a stable, fertile, and reproductively isolated lineage results from hybridization between two distinct species without a change in ploidy level. Reproductive isolation between a homoploid hybrid species and its parents is generally attained via chromosomal re...

  4. Hybrid quantum information processing

    SciTech Connect

    Furusawa, Akira

    2014-12-04

    I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

  5. Hybrid rocket instability

    NASA Technical Reports Server (NTRS)

    Greiner, B.; Frederick, R. A., Jr.

    1993-01-01

    The paper provides a brief review of theoretical and experimental studies concerned with hybrid rocket instability. The instabilities discussed include atomization and mixing instabilities, chuffing instabilities, pressure coupled combustion instabilities, and vortex shedding. It is emphasized that the future use of hybrid motor systems as viable design alternatives will depend on a better understanding of hybrid instability.

  6. Hybrid rocket instability

    NASA Astrophysics Data System (ADS)

    Greiner, B.; Frederick, R. A., Jr.

    1993-06-01

    The paper provides a brief review of theoretical and experimental studies concerned with hybrid rocket instability. The instabilities discussed include atomization and mixing instabilities, chuffing instabilities, pressure coupled combustion instabilities, and vortex shedding. It is emphasized that the future use of hybrid motor systems as viable design alternatives will depend on a better understanding of hybrid instability.

  7. Core sample extractor

    NASA Technical Reports Server (NTRS)

    Akins, James; Cobb, Billy; Hart, Steve; Leaptrotte, Jeff; Milhollin, James; Pernik, Mark

    1989-01-01

    The problem of retrieving and storing core samples from a hole drilled on the lunar surface is addressed. The total depth of the hole in question is 50 meters with a maximum diameter of 100 millimeters. The core sample itself has a diameter of 60 millimeters and will be two meters in length. It is therefore necessary to retrieve and store 25 core samples per hole. The design utilizes a control system that will stop the mechanism at a certain depth, a cam-linkage system that will fracture the core, and a storage system that will save and catalogue the cores to be extracted. The Rod Changer and Storage Design Group will provide the necessary tooling to get into the hole as well as to the core. The mechanical design for the cam-linkage system as well as the conceptual design of the storage device are described.

  8. The core paradox.

    NASA Technical Reports Server (NTRS)

    Kennedy, G. C.; Higgins, G. H.

    1973-01-01

    Rebuttal of suggestions from various critics attempting to provide an escape from the seeming paradox originated by Higgins and Kennedy's (1971) proposed possibility that the liquid in the outer core was thermally stably stratified and that this stratification might prove a powerful inhibitor to circulation of the outer core fluid of the kind postulated for the generation of the earth's magnetic field. These suggestions are examined and shown to provide no reasonable escape from the core paradox.

  9. Probing Compositional Variation within Hybrid Nanostructures

    SciTech Connect

    Yuhas, Benjamin D.; Habas, Susan E.; Fakra, Sirine C.; Mokari, Taleb

    2010-06-22

    We present a detailed analysis of the structural and magnetic properties of solution-grown PtCo-CdS hybrid structures in comparison to similar free-standing PtCo alloy nanoparticles. X-ray absorption spectroscopy is utilized as a sensitive probe for identifying subtle differences in the structure of the hybrid materials. We found that the growth of bimetallic tips on a CdS nanorod substrate leads to a more complex nanoparticle structure composed of a PtCo alloy core and thin CoO shell. The core-shell architecture is an unexpected consequence of the different nanoparticle growth mechanism on the nanorod tip, as compared to free growth in solution. Magnetic measurements indicate that the PtCo-CdS hybrid structures are superparamagnetic despite the presence of a CoO shell. The use of X-ray spectroscopic techniques to detect minute differences in atomic structure and bonding in complex nanosystems makes it possible to better understand and predict catalytic or magnetic properties for nanoscale bimetallic hybrid materials.

  10. AN Core Analysis

    NASA Astrophysics Data System (ADS)

    Barbarino, Andrea; Tomatis, Daniele

    2014-06-01

    Several alternative approximations of neutron transport have been proposed in years to move around the known limitations imposed by neutron diffusion in the modeling of nuclear cores. However, only a few complied with the industrial requirements of fast numerical computation, concentrating more on physical accuracy. In this work, the AN transport methodology is discussed with particular interest in core performance calculations. The implementation of the methodology in full core codes is discussed with particular attention to numerical issues and to the integration within the entire simulation process. Finally, first results from core studies in AN transport are analyzed in detail and compared to standard results of neutron diffusion.

  11. Helicopter engine core noise

    NASA Astrophysics Data System (ADS)

    Vonglahn, U. H.

    1982-07-01

    Calculated engine core noise levels, based on NASA Lewis prediction procedures, for five representative helicopter engines are compared with measured total helicopter noise levels and ICAO helicopter noise certification requirements. Comparisons are made for level flyover and approach procedures. The measured noise levels are generally significantly greater than those predicted for the core noise levels, except for the Sikorsky S-61 and S-64 helicopters. However, the predicted engine core noise levels are generally at or within 3 dB of the ICAO noise rules. Consequently, helicopter engine core noise can be a significant contributor to the overall helicopter noise signature.

  12. Helicopter engine core noise

    NASA Technical Reports Server (NTRS)

    Vonglahn, U. H.

    1982-01-01

    Calculated engine core noise levels, based on NASA Lewis prediction procedures, for five representative helicopter engines are compared with measured total helicopter noise levels and ICAO helicopter noise certification requirements. Comparisons are made for level flyover and approach procedures. The measured noise levels are generally significantly greater than those predicted for the core noise levels, except for the Sikorsky S-61 and S-64 helicopters. However, the predicted engine core noise levels are generally at or within 3 dB of the ICAO noise rules. Consequently, helicopter engine core noise can be a significant contributor to the overall helicopter noise signature.

  13. Core Research Center

    USGS Publications Warehouse

    Hicks, Joshua; Adrian, Betty

    2009-01-01

    The Core Research Center (CRC) of the U.S. Geological Survey (USGS), located at the Denver Federal Center in Lakewood, Colo., currently houses rock core from more than 8,500 boreholes representing about 1.7 million feet of rock core from 35 States and cuttings from 54,000 boreholes representing 238 million feet of drilling in 28 States. Although most of the boreholes are located in the Rocky Mountain region, the geologic and geographic diversity of samples have helped the CRC become one of the largest and most heavily used public core repositories in the United States. Many of the boreholes represented in the collection were drilled for energy and mineral exploration, and many of the cores and cuttings were donated to the CRC by private companies in these industries. Some cores and cuttings were collected by the USGS along with other government agencies. Approximately one-half of the cores are slabbed and photographed. More than 18,000 thin sections and a large volume of analytical data from the cores and cuttings are also accessible. A growing collection of digital images of the cores are also becoming available on the CRC Web site Internet http://geology.cr.usgs.gov/crc/.

  14. Hybridization and extinction.

    PubMed

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities. PMID:27468307

  15. Sumoylation of the Core Protein in Classical Swine Fever Virus is Essential for Virulence in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The classical swine fever virus core protein makes up the nucleocapsid of the virus, and is serves both as a protective function for the viral RNA and a transcriptional regulator in the host cell. To identify host proteins that interact with the viral Core protein we utilized the yeast two-hybrid to...

  16. Core Skills in Action.

    ERIC Educational Resources Information Center

    Further Education Unit, London (England).

    This bulletin provides an update on current developments in core skills in further education. Section 1 contains information about the Further Education Unit's (FEU's) Core Skills Post-16 project, in which colleges are testing principles that underpin all good quality learning programs. Important findings and examples are outlined under the five…

  17. Reconceptualising Core Skills

    ERIC Educational Resources Information Center

    Canning, Roy

    2007-01-01

    The paper provides an analysis of Core Skill policy and practice in the UK. The author presents a conceptual basis for re-thinking generic Core Skills within educational approaches in teaching and learning. The discussion looks at whether universal notions of generic skills are appropriate when considering post-compulsory pedagogic approaches to…

  18. The Common Core.

    ERIC Educational Resources Information Center

    Boyer, Ernest L.

    Current curricula in institutions of higher education are criticized in this speech for their lack of a common core of education. Several possibilities for developing such a common core include education centered around our common heritage and the challenges of the present. It is suggested that all students must be introduced to the events,…

  19. Making an Ice Core.

    ERIC Educational Resources Information Center

    Kopaska-Merkel, David C.

    1995-01-01

    Explains an activity in which students construct a simulated ice core. Materials required include only a freezer, food coloring, a bottle, and water. This hands-on exercise demonstrates how a glacier is formed, how ice cores are studied, and the nature of precision and accuracy in measurement. Suitable for grades three through eight. (Author/PVD)

  20. Iowa Core Annual Report

    ERIC Educational Resources Information Center

    Iowa Department of Education, 2015

    2015-01-01

    One central component of a great school system is a clear set of expectations, or standards, that educators help all students reach. In Iowa, that effort is known as the Iowa Core. The Iowa Core represents the statewide academic standards, which describe what students should know and be able to do in math, science, English language arts, and…

  1. CORE - Performance Feedback System

    Energy Science and Technology Software Center (ESTSC)

    2009-10-02

    CORE is an architecture to bridge the gaps between disparate data integration and delivery of disparate information visualization. The CORE Technology Program includes a suite of tools and user-centered staff that can facilitate rapid delivery of a deployable integrated information to users.

  2. Ice Core Investigations

    ERIC Educational Resources Information Center

    Krim, Jessica; Brody, Michael

    2008-01-01

    What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

  3. NFE Core Bibliographies.

    ERIC Educational Resources Information Center

    Michigan State Univ., East Lansing. Inst. for International Studies in Education.

    This collection of core bibliographies, which expands on an initial bibliography published in 1979 of the core resources housed in the Non-Formal Education Information Center at Michigan State University, comprises a basic stock of materials on nonformal education and women in development that have been contributed by development planners,…

  4. Lunar Core and Tides

    NASA Technical Reports Server (NTRS)

    Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.

    2004-01-01

    Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2,3,4] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacements. Past solutions using the LLR data have given results for dissipation due to solid-body tides and fluid core [1] plus Love number [1-5]. Detection of CMB flattening, which in the past has been marginal but improving [3,4,5], now seems significant. Direct detection of the core moment has not yet been achieved.

  5. Internal core tightener

    DOEpatents

    Brynsvold, Glen V.; Snyder, Jr., Harold J.

    1976-06-22

    An internal core tightener which is a linear actuated (vertical actuation motion) expanding device utilizing a minimum of moving parts to perform the lateral tightening function. The key features are: (1) large contact areas to transmit loads during reactor operation; (2) actuation cam surfaces loaded only during clamping and unclamping operation; (3) separation of the parts and internal operation involved in the holding function from those involved in the actuation function; and (4) preloaded pads with compliant travel at each face of the hexagonal assembly at the two clamping planes to accommodate thermal expansion and irradiation induced swelling. The latter feature enables use of a "fixed" outer core boundary, and thus eliminates the uncertainty in gross core dimensions, and potential for rapid core reactivity changes as a result of core dimensional change.

  6. Probing DNA hybridization efficiency and single base mismatch by X-ray photoelectron spectroscopy.

    PubMed

    Liu, Zheng-Chun; Zhang, Xin; He, Nong-Yue; Lu, Zu-Hong; Chen, Zhen-Cheng

    2009-07-01

    We demonstrated the use of X-ray photoelectron spectroscopy (XPS) to study DNA hybridization. Target DNA labeled with hexachloro-fluorescein (HEX) was hybridized to DNA arrays with four different probes. Each probe dot of the hybridized arrays was detected with XPS. The XPS Cl2p peak areas were found to decrease with an increase in mismatched bases in DNA probes. The Cl2p core-level peak area ratio of a probe perfectly matched to one, two and three base-mismatched probes accorded well with the results of conventional fluorescent imaging, which shows that XPS is a potential tool for analyzing DNA arrays. The DNA arrays' hybridization efficiency was assessed by the molar ratio of chlorine to phosphorus in a DNA strand, which was determined from the relevant XPS Cl2p and P2p core-level peak areas after hybridization. This could provide a new method to detect DNA hybridization efficiency. PMID:19282155

  7. STEM image simulation with hybrid CPU/GPU programming.

    PubMed

    Yao, Y; Ge, B H; Shen, X; Wang, Y G; Yu, R C

    2016-07-01

    STEM image simulation is achieved via hybrid CPU/GPU programming under parallel algorithm architecture to speed up calculation on a personal computer (PC). To utilize the calculation power of a PC fully, the simulation is performed using the GPU core and multi-CPU cores at the same time to significantly improve efficiency. GaSb and an artificial GaSb/InAs interface with atom diffusion have been used to verify the computation. PMID:27093687

  8. 34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES CORES THAT ARE NOT MADE ON HEATED OR COLD BOX CORE MACHINES, TO SET BINDING AGENTS MIXED WITH THE SAND CREATING CORES HARD ENOUGH TO WITHSTAND THE FLOW OF MOLTEN IRON INSIDE A MOLD. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  9. New organic-inorganic hybrid molecular systems and highly organized materials in catalysis

    NASA Astrophysics Data System (ADS)

    Kustov, L. M.

    2015-11-01

    Definitions of hybrid materials are suggested, and applications of these materials are considered. Particular attention is focused on the application of hybrid materials in hydrogenation, partial oxidation, plant biomass conversion, and natural gas reforming, primarily on the use of core-shell nanoparticles and decorated metal nanoparticles in these reactions. Application prospects of various hybrid materials, particularly those of metal-organic frameworks, are discussed.

  10. Multiple Core Galaxies

    NASA Technical Reports Server (NTRS)

    Miller, R.H.; Morrison, David (Technical Monitor)

    1994-01-01

    Nuclei of galaxies often show complicated density structures and perplexing kinematic signatures. In the past we have reported numerical experiments indicating a natural tendency for galaxies to show nuclei offset with respect to nearby isophotes and for the nucleus to have a radial velocity different from the galaxy's systemic velocity. Other experiments show normal mode oscillations in galaxies with large amplitudes. These oscillations do not damp appreciably over a Hubble time. The common thread running through all these is that galaxies often show evidence of ringing, bouncing, or sloshing around in unexpected ways, even though they have not been disturbed by any external event. Recent observational evidence shows yet another phenomenon indicating the dynamical complexity of central regions of galaxies: multiple cores (M31, Markarian 315 and 463 for example). These systems can hardly be static. We noted long-lived multiple core systems in galaxies in numerical experiments some years ago, and we have more recently followed up with a series of experiments on multiple core galaxies, starting with two cores. The relevant parameters are the energy in the orbiting clumps, their relative.masses, the (local) strength of the potential well representing the parent galaxy, and the number of cores. We have studied the dependence of the merger rates and the nature of the final merger product on these parameters. Individual cores survive much longer in stronger background potentials. Cores can survive for a substantial fraction of a Hubble time if they travel on reasonable orbits.

  11. Quantum photonics hybrid integration platform

    SciTech Connect

    Murray, E.; Floether, F. F.; Ellis, D. J. P.; Meany, T.; Bennett, A. J. Shields, A. J.; Lee, J. P.; Griffiths, J. P.; Jones, G. A. C.; Farrer, I.; Ritchie, D. A.

    2015-10-26

    Fundamental to integrated photonic quantum computing is an on-chip method for routing and modulating quantum light emission. We demonstrate a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single-photon sources. InAs quantum dots (QD) embedded in GaAs are bonded to a SiON waveguide chip such that the QD emission is coupled to the waveguide mode. The waveguides are SiON core embedded in a SiO{sub 2} cladding. A tuneable Mach Zehnder interferometer (MZI) modulates the emission between two output ports and can act as a path-encoded qubit preparation device. The single-photon nature of the emission was verified using the on-chip MZI as a beamsplitter in a Hanbury Brown and Twiss measurement.

  12. Global Core Plasma Model

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis L.; Craven, P. D.; Comfort, R. H.

    1999-01-01

    Abstract. The Global Core Plasma Model (GCPM) provides, empirically derived, core plasma density as a function of geomagnetic and solar conditions throughout the inner magnetosphere. It is continuous in value and gradient and is composed of separate models for the ionosphere, the plasmasphere, the plasmapause, the trough, and the polar cap. The relative composition of plasmaspheric H+, He+, and O+ is included in the GCPM. A blunt plasmaspheric bulge and rotation of the bulge with changing geomagnetic conditions is included. The GCPM is an amalgam of density models, intended to serve as a framework for continued improvement as new measurements become available and are used to characterize core plasma density, composition, and temperature.

  13. Boson core compressibility

    NASA Astrophysics Data System (ADS)

    Khorramzadeh, Y.; Lin, Fei; Scarola, V. W.

    2012-04-01

    Strongly interacting atoms trapped in optical lattices can be used to explore phase diagrams of Hubbard models. Spatial inhomogeneity due to trapping typically obscures distinguishing observables. We propose that measures using boson double occupancy avoid trapping effects to reveal two key correlation functions. We define a boson core compressibility and core superfluid stiffness in terms of double occupancy. We use quantum Monte Carlo on the Bose-Hubbard model to empirically show that these quantities intrinsically eliminate edge effects to reveal correlations near the trap center. The boson core compressibility offers a generally applicable tool that can be used to experimentally map out phase transitions between compressible and incompressible states.

  14. Core shroud corner joints

    DOEpatents

    Gilmore, Charles B.; Forsyth, David R.

    2013-09-10

    A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

  15. Hybrid radiator cooling system

    DOEpatents

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  16. Coherent control in hybrid materials

    NASA Astrophysics Data System (ADS)

    Tian, Chao; Sukharev, Maxim; Malinovskaya, Svetlana

    2013-05-01

    A quickly growing field of hybrid materials is emerging on the base of latest advancements in nanoplasmonic science. Here one merges plasmonics with atomic and molecular physics considering systems comprised of quantum emitters and metal nano-structures. Such systems exhibit a wide variety of new phenomena. It has long been realized that quantum control could be successfully applied to optically active nano-systems. In this paper we explore the ideas of stimulated Raman adiabatic passage (STIRAP) applied to ensembles of atoms optically coupled to plasmonic systems. We demonstrate the implementation of STIRAP as a tool to control scattering, reflection, and transmission properties of hybrid systems. As an example we consider a core-shell silver nanowire with resonantly coupled layer of three-level atoms. A self-consistent model of Maxwell-Liouville-von Neumann equations is implemented that allows taking into account the collective effects between atoms. We show that both linear and nonlinear optical properties of atomic ensembles may be controlled by coupling to plasmonic nano-structures. The work is partially supported by NSF.

  17. Managing hybrid marketing systems.

    PubMed

    Moriarty, R T; Moran, U

    1990-01-01

    As competition increases and costs become critical, companies that once went to market only one way are adding new channels and using new methods - creating hybrid marketing systems. These hybrid marketing systems hold the promise of greater coverage and reduced costs. But they are also hard to manage; they inevitably raise questions of conflict and control: conflict because marketing units compete for customers; control because new indirect channels are less subject to management authority. Hard as they are to manage, however, hybrid marketing systems promise to become the dominant design, replacing the "purebred" channel strategy in all kinds of businesses. The trick to managing the hybrid is to analyze tasks and channels within and across a marketing system. A map - the hybrid grid - can help managers make sense of their hybrid system. What the chart reveals is that channels are not the basic building blocks of a marketing system; marketing tasks are. The hybrid grid forces managers to consider various combinations of channels and tasks that will optimize both cost and coverage. Managing conflict is also an important element of a successful hybrid system. Managers should first acknowledge the inevitability of conflict. Then they should move to bound it by creating guidelines that spell out which customers to serve through which methods. Finally, a marketing and sales productivity (MSP) system, consisting of a central marketing database, can act as the central nervous system of a hybrid marketing system, helping managers create customized channels and service for specific customer segments. PMID:10107959

  18. Hybridization facilitates evolutionary rescue

    PubMed Central

    Stelkens, Rike B; Brockhurst, Michael A; Hurst, Gregory D D; Greig, Duncan

    2014-01-01

    The resilience of populations to rapid environmental degradation is a major concern for biodiversity conservation. When environments deteriorate to lethal levels, species must evolve to adapt to the new conditions to avoid extinction. Here, we test the hypothesis that evolutionary rescue may be enabled by hybridization, because hybridization increases genetic variability. Using experimental evolution, we show that interspecific hybrid populations of Saccharomyces yeast adapt to grow in more highly degraded environments than intraspecific and parental crosses, resulting in survival rates far exceeding those of their ancestors. We conclude that hybridization can increase evolutionary responsiveness and that taxa able to exchange genes with distant relatives may better survive rapid environmental change. PMID:25558281

  19. Biospecimen Core Resource - TCGA

    Cancer.gov

    The Cancer Genome Atlas (TCGA) Biospecimen Core Resource centralized laboratory reviews and processes blood and tissue samples and their associated data using optimized standard operating procedures for the entire TCGA Research Network.

  20. Contaminated Sediment Core Profiling

    EPA Science Inventory

    Evaluating the environmental risk of sites containing contaminated sediments often poses major challenges due in part to the absence of detailed information available for a given location. Sediment core profiling is often utilized during preliminary environmental investigations ...

  1. Core assembly storage structure

    DOEpatents

    Jones, Jr., Charles E.; Brunings, Jay E.

    1988-01-01

    A structure for the storage of core assemblies from a liquid metal-cooled nuclear reactor. The structure comprises an enclosed housing having a substantially flat horizontal top plate, a bottom plate and substantially vertical wall members extending therebetween. A plurality of thimble members extend downwardly through the top plate. Each thimble member is closed at its bottom end and has an open end adjacent said top plate. Each thimble member has a length and diameter greater than that of the core assembly to be stored therein. The housing is provided with an inlet duct for the admission of cooling air and an exhaust duct for the discharge of air therefrom, such that when hot core assemblies are placed in the thimbles, the heat generated will by convection cause air to flow from the inlet duct around the thimbles and out the exhaust duct maintaining the core assemblies at a safe temperature without the necessity of auxiliary powered cooling equipment.

  2. Geophysics: Earth's core problem

    NASA Astrophysics Data System (ADS)

    Dobson, David

    2016-06-01

    Measurements of the electrical resistance and thermal conductivity of iron at extreme pressures and temperatures cast fresh light on controversial numerical simulations of the properties of Earth's outer core. See Letters p.95 & 99

  3. Magnetorotational iron core collapse

    NASA Technical Reports Server (NTRS)

    Symbalisty, E. M. D.

    1984-01-01

    During its final evolutionary stages, a massive star, as considered in current astrophysical theory, undergoes rapid collapse, thereby triggering a sequence of a catastrophic event which results in a Type II supernova explosion. A remnant neutron star or a black hole is left after the explosion. Stellar collapse occurs, when thermonuclear fusion has consumed the lighter elements present. At this stage, the core consists of iron. Difficulties arise regarding an appropriate model with respect to the core collapse. The present investigation is concerned with the evolution of a Type II supernova core including the effects of rotation and magnetic fields. A simple neutrino model is developed which reproduced the spherically symmetric results of Bowers and Wilson (1982). Several two-dimensional computational models of stellar collapse are studied, taking into account a case in which a 15 solar masses iron core was artificially given rotational and magnetic energy.

  4. Core-Noise Research

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2012-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015 (N+1), 2020 (N+2), and 2025 (N+3) timeframes; SFW strategic thrusts and technical challenges; SFW advanced subsystems that are broadly applicable to N+3 vehicle concepts, with an indication where further noise research is needed; the components of core noise (compressor, combustor and turbine noise) and a rationale for NASA's current emphasis on the combustor-noise component; the increase in the relative importance of core noise due to turbofan design trends; the need to understand and mitigate core-noise sources for high-efficiency small gas generators; and the current research activities in the core-noise area, with additional details given about forthcoming updates to NASA's Aircraft Noise Prediction Program (ANOPP) core-noise prediction capabilities, two NRA efforts (Honeywell International, Phoenix, AZ and University of Illinois at Urbana-Champaign, respectively) to improve the understanding of core-noise sources and noise propagation through the engine core, and an effort to develop oxide/oxide ceramic-matrix-composite (CMC) liners for broadband noise attenuation suitable for turbofan-core application. Core noise must be addressed to ensure that the N+3 noise goals are met. Focused, but long-term, core-noise research is carried out to enable the advanced high-efficiency small gas-generator subsystem, common to several N+3 conceptual designs, needed to meet NASA's technical challenges. Intermediate updates to prediction tools are implemented as the understanding of the source structure and engine-internal propagation effects is improved. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The

  5. Core bounce supernovae

    SciTech Connect

    Cooperstein, J.

    1987-01-01

    The gravitational collapse mechanism for Type II supernovae is considered, concentrating on the direct implosion - core bounce - hydrodynamic explosion picture. We examine the influence of the stiffness of the dense matter equation of state and discuss how the shock wave is formed. Its chances of success are determined by the equation of state, general relativistic effects, neutrino transport, and the size of presupernova iron core. 12 refs., 1 tab.

  6. Micro coring apparatus

    NASA Technical Reports Server (NTRS)

    Collins, David; Brooks, Marshall; Chen, Paul; Dwelle, Paul; Fischer, Ben

    1989-01-01

    A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

  7. Nuclear core positioning system

    DOEpatents

    Garkisch, Hans D.; Yant, Howard W.; Patterson, John F.

    1979-01-01

    A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

  8. MCNP LWR Core Generator

    SciTech Connect

    Fischer, Noah A.

    2012-08-14

    The reactor core input generator allows for MCNP input files to be tailored to design specifications and generated in seconds. Full reactor models can now easily be created by specifying a small set of parameters and generating an MCNP input for a full reactor core. Axial zoning of the core will allow for density variation in the fuel and moderator, with pin-by-pin fidelity, so that BWR cores can more accurately be modeled. LWR core work in progress: (1) Reflectivity option for specifying 1/4, 1/2, or full core simulation; (2) Axial zoning for moderator densities that vary with height; (3) Generating multiple types of assemblies for different fuel enrichments; and (4) Parameters for specifying BWR box walls. Fuel pin work in progress: (1) Radial and azimuthal zoning for generating further unique materials in fuel rods; (2) Options for specifying different types of fuel for MOX or multiple burn assemblies; (3) Additional options for replacing fuel rods with burnable poison rods; and (4) Control rod/blade modeling.

  9. Emergency core cooling system

    DOEpatents

    Schenewerk, William E.; Glasgow, Lyle E.

    1983-01-01

    A liquid metal cooled fast breeder reactor provided with an emergency core cooling system includes a reactor vessel which contains a reactor core comprising an array of fuel assemblies and a plurality of blanket assemblies. The reactor core is immersed in a pool of liquid metal coolant. The reactor also includes a primary coolant system comprising a pump and conduits for circulating liquid metal coolant to the reactor core and through the fuel and blanket assemblies of the core. A converging-diverging venturi nozzle with an intermediate throat section is provided in between the assemblies and the pump. The intermediate throat section of the nozzle is provided with at least one opening which is in fluid communication with the pool of liquid sodium. In normal operation, coolant flows from the pump through the nozzle to the assemblies with very little fluid flowing through the opening in the throat. However, when the pump is not running, residual heat in the core causes fluid from the pool to flow through the opening in the throat of the nozzle and outwardly through the nozzle to the assemblies, thus providing a means of removing decay heat.

  10. From hybrid swarms to swarms of hybrids

    USGS Publications Warehouse

    Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

    2015-01-01

    Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

  11. The Hybrid Master's Degree: Combining Research with Practice.

    ERIC Educational Resources Information Center

    Coulson, David C.; Linn, Travis

    1995-01-01

    Describes the development of a hybrid master's degree that combines research and practice at the University of Nevada-Reno. Relates how the curriculum in journalism and mass communication was developed, including descriptions of core courses and applied research techniques. Concludes that while the experience has not been completely satisfactory,…

  12. Core-Noise

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2010-01-01

    This presentation is a technical progress report and near-term outlook for NASA-internal and NASA-sponsored external work on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system level noise metrics for the 2015, 2020, and 2025 timeframes; the emerging importance of core noise and its relevance to the SFW Reduced-Noise-Aircraft Technical Challenge; the current research activities in the core-noise area, with some additional details given about the development of a high-fidelity combustion-noise prediction capability; the need for a core-noise diagnostic capability to generate benchmark data for validation of both high-fidelity work and improved models, as well as testing of future noise-reduction technologies; relevant existing core-noise tests using real engines and auxiliary power units; and examples of possible scenarios for a future diagnostic facility. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Noise-Aircraft Technical Challenge aims to enable concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical for enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor designs could increase

  13. Large-Scale Hybrid Motor Testing. Chapter 10

    NASA Technical Reports Server (NTRS)

    Story, George

    2006-01-01

    Hybrid rocket motors can be successfully demonstrated at a small scale virtually anywhere. There have been many suitcase sized portable test stands assembled for demonstration of hybrids. They show the safety of hybrid rockets to the audiences. These small show motors and small laboratory scale motors can give comparative burn rate data for development of different fuel/oxidizer combinations, however questions that are always asked when hybrids are mentioned for large scale applications are - how do they scale and has it been shown in a large motor? To answer those questions, large scale motor testing is required to verify the hybrid motor at its true size. The necessity to conduct large-scale hybrid rocket motor tests to validate the burn rate from the small motors to application size has been documented in several place^'^^.^. Comparison of small scale hybrid data to that of larger scale data indicates that the fuel burn rate goes down with increasing port size, even with the same oxidizer flux. This trend holds for conventional hybrid motors with forward oxidizer injection and HTPB based fuels. While the reason this is occurring would make a great paper or study or thesis, it is not thoroughly understood at this time. Potential causes include the fact that since hybrid combustion is boundary layer driven, the larger port sizes reduce the interaction (radiation, mixing and heat transfer) from the core region of the port. This chapter focuses on some of the large, prototype sized testing of hybrid motors. The largest motors tested have been AMROC s 250K-lbf thrust motor at Edwards Air Force Base and the Hybrid Propulsion Demonstration Program s 250K-lbf thrust motor at Stennis Space Center. Numerous smaller tests were performed to support the burn rate, stability and scaling concepts that went into the development of those large motors.

  14. Hybrid baryons [alpha].

    SciTech Connect

    Page, P. R.

    2002-01-01

    The authors review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modeled by both the bag and flux tube models. The low lying hybrid baryon is N 1/2{sup +} with a mass of 1.5 - 1.8 GeV. Hybrid baryons can be produced in the glue rich processes of diffractive {gamma}N and {pi}N production, {Psi} decays and p{bar p} annihilation. We review the current status of research on three quarks with a gluonic excitation, called a hybrid baryon. The excitation is not an orbital or radial excitation between the quarks. Hybrid baryons have also been reviewed elsewhere. The Mercedes-Benz logl in Figure 1 indicates two possible views of the confining interaction of three quarks, an essential issue in the study of hybrid baryons. In the logo the three points where the Y shape meets the boundary circle should be identified with the three quarks. There are two possibilities fo rthe interaction of the quarks: (1) a pairwise interaction of the quarks represented by the circle, or (2) a Y shaped interaction between the quarks, represented by the Y-shape in the logo.

  15. Hybrid Rocket Motor Test

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A 10,000-pound thrust hybrid rocket motor is tested at Stennis Space Center's E-1 test facility. A hybrid rocket motor is a cross between a solid rocket and a liquid-fueled engine. It uses environmentally safe solid fuel and liquid oxygen.

  16. One-pot construction of multipodal hybrid periodic mesoporous organosilica nanoparticles with crystal-like architectures.

    PubMed

    Croissant, Jonas; Cattoën, Xavier; Wong Chi Man, Michel; Dieudonné, Philippe; Charnay, Clarence; Raehm, Laurence; Durand, Jean-Olivier

    2015-01-01

    The design of hybrid multipodal PMO (mp-PMO) nanoparticles with crystal-like architectures elaborated in a one-pot, two-step process, involving the preparation of a benzene-based spherical PMO core followed by the formation of ethylene-based rod-shaped PMO pods on these cores is described. PMID:25378091

  17. Hybrid reactors. [Fuel cycle

    SciTech Connect

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

  18. Hybrid rocket performance

    NASA Astrophysics Data System (ADS)

    Frederick, Robert A., Jr.

    1992-12-01

    A hybrid rocket is a system consisting of a solid fuel grain and a gaseous or liquid oxidizer. Figure 1 shows three popular hybrid propulsion cycles that are under current consideration. NASA MSFC has teamed with industry to test two hybrid propulsion systems that will allow scaling to motors of potential interest for Titan and Atlas systems, as well as encompassing the range of interest for SEI lunar ascent stages and National Launch System Cargo Transfer Vehicle (NLS CTV) and NLS deorbit systems. Hybrid systems also offer advantages as moderate-cost, environmentally acceptable propulsion system. The objective of this work was to recommend a performance prediction methodology for hybrid rocket motors. The scope included completion of: a literature review, a general methodology, and a simplified performance model.

  19. Hybrid rocket performance

    NASA Technical Reports Server (NTRS)

    Frederick, Robert A., Jr.

    1992-01-01

    A hybrid rocket is a system consisting of a solid fuel grain and a gaseous or liquid oxidizer. Figure 1 shows three popular hybrid propulsion cycles that are under current consideration. NASA MSFC has teamed with industry to test two hybrid propulsion systems that will allow scaling to motors of potential interest for Titan and Atlas systems, as well as encompassing the range of interest for SEI lunar ascent stages and National Launch System Cargo Transfer Vehicle (NLS CTV) and NLS deorbit systems. Hybrid systems also offer advantages as moderate-cost, environmentally acceptable propulsion system. The objective of this work was to recommend a performance prediction methodology for hybrid rocket motors. The scope included completion of: a literature review, a general methodology, and a simplified performance model.

  20. Hybrid propulsion technology program

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Technology was identified which will enable application of hybrid propulsion to manned and unmanned space launch vehicles. Two design concepts are proposed. The first is a hybrid propulsion system using the classical method of regression (classical hybrid) resulting from the flow of oxidizer across a fuel grain surface. The second system uses a self-sustaining gas generator (gas generator hybrid) to produce a fuel rich exhaust that was mixed with oxidizer in a separate combustor. Both systems offer cost and reliability improvement over the existing solid rocket booster and proposed liquid boosters. The designs were evaluated using life cycle cost and reliability. The program consisted of: (1) identification and evaluation of candidate oxidizers and fuels; (2) preliminary evaluation of booster design concepts; (3) preparation of a detailed point design including life cycle costs and reliability analyses; (4) identification of those hybrid specific technologies needing improvement; and (5) preperation of a technology acquisition plan and large scale demonstration plan.

  1. Hybrid baryons in QCD

    SciTech Connect

    Dudek, Jozef J.; Edwards, Robert G.

    2012-03-21

    In this study, we present the first comprehensive study of hybrid baryons using lattice QCD methods. Using a large basis of composite QCD interpolating fields we extract an extensive spectrum of baryon states and isolate those of hybrid character using their relatively large overlap onto operators which sample gluonic excitations. We consider the spectrum of Nucleon and Delta states at several quark masses finding a set of positive parity hybrid baryons with quantum numbers $N_{1/2^+},\\,N_{1/2^+},\\,N_{3/2^+},\\, N_{3/2^+},\\,N_{5/2^+},\\,$ and $\\Delta_{1/2^+},\\, \\Delta_{3/2^+}$ at an energy scale above the first band of `conventional' excited positive parity baryons. This pattern of states is compatible with a color octet gluonic excitation having $J^{P}=1^{+}$ as previously reported in the hybrid meson sector and with a comparable energy scale for the excitation, suggesting a common bound-state construction for hybrid mesons and baryons.

  2. Core Noise - Increasing Importance

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduced-Perceived-Noise Technical Challenge; and the current research activities in the core-noise area, with additional details given about the development of a high-fidelity combustor-noise prediction capability as well as activities supporting the development of improved reduced-order, physics-based models for combustor-noise prediction. The need for benchmark data for validation of high-fidelity and modeling work and the value of a potential future diagnostic facility for testing of core-noise-reduction concepts are indicated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor

  3. Pressure Core Characterization

    NASA Astrophysics Data System (ADS)

    Santamarina, J. C.

    2014-12-01

    Natural gas hydrates form under high fluid pressure and low temperature, and are found in permafrost, deep lakes or ocean sediments. Hydrate dissociation by depressurization and/or heating is accompanied by a multifold hydrate volume expansion and host sediments with low permeability experience massive destructuration. Proper characterization requires coring, recovery, manipulation and testing under P-T conditions within the stability field. Pressure core technology allows for the reliable characterization of hydrate bearing sediments within the stability field in order to address scientific and engineering needs, including the measurement of parameters used in hydro-thermo-mechanical analyses, and the monitoring of hydrate dissociation under controlled pressure, temperature, effective stress and chemical conditions. Inherent sampling effects remain and need to be addressed in test protocols and data interpretation. Pressure core technology has been deployed to study hydrate bearing sediments at several locations around the world. In addition to pressure core testing, a comprehensive characterization program should include sediment analysis, testing of reconstituted specimens (with and without synthetic hydrate), and in situ testing. Pressure core characterization technology can be used to study other gas-charged formations such as deep sea sediments, coal bed methane and gas shales.

  4. Core Noise Reduction

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduce-Perceived-Noise Technical Challenge; and the current research activities in the core noise area. Recent work1 on the turbine-transmission loss of combustor noise is briefly described, two2,3 new NRA efforts in the core-noise area are outlined, and an effort to develop CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is delineated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Subsonic Fixed Wing Project's Reduce-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries.

  5. Earth's core iron

    NASA Astrophysics Data System (ADS)

    Geophysicist J. Michael Brown of Texas A & M University noted recently at the Spring AGU Meeting in Baltimore that the structure and phase of metallic iron at pressures of the earth's inner core (approximately 3.3 Mbar) could have great significance in defining geometrical aspects of the core itself. Brown worked at the Los Alamos Scientific Laboratory with R.B. McQueen to redetermine the phase relations of metallic iron in a series of new shock-wave experiments. They found the melting point of iron at conditions equal to those at the boundary of the earth's outer (liquid) and inner (solid) cores to be 6000°±500°C (Geophysical Research Letters, 7, 533-536, 1980).

  6. Mars' Inner Core

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This figure shows a cross-section of the planet Mars revealing an inner, high density core buried deep within the interior. Dipole magnetic field lines are drawn in blue, showing the global scale magnetic field that one associates with dynamo generation in the core. Mars must have one day had such a field, but today it is not evident. Perhaps the energy source that powered the early dynamo has shut down. The differentiation of the planet interior - heavy elements like iron sinking towards the center of the planet - can provide energy as can the formation of a solid core from the liquid.

    The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. JPL is an operating division of California Institute of Technology (Caltech).

  7. Molten core retention assembly

    DOEpatents

    Lampe, Robert F.

    1976-06-22

    Molten fuel produced in a core overheating accident is caught by a molten core retention assembly consisting of a horizontal baffle plate having a plurality of openings therein, heat exchange tubes having flow holes near the top thereof mounted in the openings, and a cylindrical, imperforate baffle attached to the plate and surrounding the tubes. The baffle assembly is supported from the core support plate of the reactor by a plurality of hanger rods which are welded to radial beams passing under the baffle plate and intermittently welded thereto. Preferably the upper end of the cylindrical baffle terminates in an outwardly facing lip to which are welded a plurality of bearings having slots therein adapted to accept the hanger rods.

  8. Core Subcriticality as a Tool of Safety Enhancement

    SciTech Connect

    Bokov, Pavel M.

    2005-11-15

    Core subcriticality can play an important role if the safety enhancement of a nuclear system is necessary, in particular, when minor actinides submitted for transmutation cause essential degradation of the reactivity feedback effects or/and significant reduction of the delayed neutron fraction. The present work shows that core subcriticality together with thermohydraulics optimization can compensate for the possible degradation of the Doppler effect and the reduction of the delayed neutron fraction. The particular dependence of the spallation neutron yield allows the creation of a supplementary negative feedback effect in case of accelerator coupled hybrid systems. A number of quantitative examples are provided in this context.

  9. CORE SATURATION BLOCKING OSCILLATOR

    DOEpatents

    Spinrad, R.J.

    1961-10-17

    A blocking oscillator which relies on core saturation regulation to control the output pulse width is described. In this arrangement an external magnetic loop is provided in which a saturable portion forms the core of a feedback transformer used with the thermionic or semi-conductor active element. A first stationary magnetic loop establishes a level of flux through the saturation portion of the loop. A second adjustable magnet moves the flux level to select a saturation point giving the desired output pulse width. (AEC)

  10. Inter-specific territoriality in a Canis hybrid zone: spatial segregation between wolves, coyotes, and hybrids.

    PubMed

    Benson, John F; Patterson, Brent R

    2013-12-01

    Gray wolves (Canis lupus) and coyotes (Canis latrans) generally exhibit intraspecific territoriality manifesting in spatial segregation between adjacent packs. However, previous studies have found a high degree of interspecific spatial overlap between sympatric wolves and coyotes. Eastern wolves (Canis lycaon) are the most common wolf in and around Algonquin Provincial Park (APP), Ontario, Canada and hybridize with sympatric gray wolves and coyotes. We hypothesized that all Canis types (wolves, coyotes, and hybrids) exhibit a high degree of spatial segregation due to greater genetic, morphologic, and ecological similarities between wolves and coyotes in this hybrid system compared with western North American ecosystems. We used global positioning system telemetry and probabilistic measures of spatial overlap to investigate spatial segregation between adjacent Canis packs. Our hypothesis was supported as: (1) the probability of locating wolves, coyotes, and hybrids within home ranges ([Formula: see text] = 0.05) or core areas ([Formula: see text] < 0.01) of adjacent packs was low; and (2) the amount of shared space use was negligible. Spatial segregation did not vary substantially in relation to genotypes of adjacent packs or local environmental conditions (i.e., harvest regulations or road densities). We provide the first telemetry-based demonstration of spatial segregation between wolves and coyotes, highlighting the novel relationships between Canis types in the Ontario hybrid zone relative to areas where wolves and coyotes are reproductively isolated. Territoriality among Canis may increase the likelihood of eastern wolves joining coyote and hybrid packs, facilitate hybridization, and could play a role in limiting expansion of the genetically distinct APP eastern wolf population. PMID:23864253