WorldWideScience

Sample records for hybrid nanoscale patterning

  1. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Hybrid, Nanoscale Phospholipid/Block Copolymer Vesicles

    Directory of Open Access Journals (Sweden)

    Bo Liedberg

    2013-09-01

    Full Text Available Hybrid phospholipid/block copolymer vesicles, in which the polymeric membrane is blended with phospholipids, display interesting self-assembly behavior, incorporating the robustness and chemical versatility of polymersomes with the softness and biocompatibility of liposomes. Such structures can be conveniently characterized by preparing giant unilamellar vesicles (GUVs via electroformation. Here, we are interested in exploring the self-assembly and properties of the analogous nanoscale hybrid vesicles (ca. 100 nm in diameter of the same composition prepared by film-hydration and extrusion. We show that the self-assembly and content-release behavior of nanoscale polybutadiene-b-poly(ethylene oxide (PB-PEO/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC hybrid phospholipid/block copolymer vesicles can be tuned by the mixing ratio of the amphiphiles. In brief, these hybrids may provide alternative tools for drug delivery purposes and molecular imaging/sensing applications and clearly open up new avenues for further investigation.

  3. Benchtop Nanoscale Patterning Using Soft Lithography

    Science.gov (United States)

    Meenakshi, Viswanathan; Babayan, Yelizaveta; Odom, Teri W.

    2007-01-01

    This paper outlines several benchtop nanoscale patterning experiments that can be incorporated into undergraduate laboratories or advanced high school chemistry curricula. The experiments, supplemented by an online video lab manual, are based on soft lithographic techniques such as replica molding, micro-molding in capillaries, and micro-contact…

  4. Nanoscale photonics using coupled hybrid plasmonic architectures

    Science.gov (United States)

    Lin, Charles; Su, Yiwen; Helmy, Amr S.

    2016-04-01

    Plasmonic waveguides, which support surface plasmon polaritons (SPP) propagating along metal-dielectric interfaces, offer strong field confinement and are ideal for the design of integrated nano-scale photonic devices. However, due to free-carrier absorption in the metal, the enhanced mode confinement inevitably entails an increase in the waveguide loss. This lowers the device figure-of-merit achievable with passive plasmonic components and in turn hinders the performance of active plasmonic components such as optical modulators.

  5. Nanoscale Organic−Inorganic Hybrid Lubricants

    KAUST Repository

    Kim, Daniel

    2011-03-15

    Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona brush that stabilizes them against aggregation. When these hybrid particles are dispersed in poly-α-olefin (PAO) oligomers, they form homogeneous nanocomposite fluids at both low and high particle loadings. By varying the volume fraction of the SiO2 nanostructures in the PAO nanocomposites, we show that exceptionally stable hybrid lubricants can be created and that their mechanical properties can be tuned to span the spectrum from simple liquids to complex gels. We further show that these hybrid lubricants simultaneously exhibit lower interfacial friction coefficients, enhanced wear and mechanical properties, and superior thermal stability in comparison with either PAO or its nanocomposites created at low nanoparticle loadings. Profilometry and energy dispersive X-ray spectroscopic analysis of the wear track show that the enhanced wear characteristics in PAO-SiO2 composite lubricants originate from two sources: localization of the SiO2 particles into the wear track and extension of the elastohydrodynamic lubrication regime to Sommerfeld numbers more than an order of magnitude larger than for PAO. © 2011 American Chemical Society.

  6. Effect of nanoscale patterned interfacial roughness on interfacial toughness.

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Jonathan A.; Moody, Neville Reid; Mook, William M. (University of Minnesota, Minneapolis, MN); Kennedy, Marian S. (Clemson University, Clemson, SC); Bahr, David F. (Washington State University, Pullman, WA); Zhou, Xiao Wang; Reedy, Earl David, Jr.

    2007-09-01

    The performance and the reliability of many devices are controlled by interfaces between thin films. In this study we investigated the use of patterned, nanoscale interfacial roughness as a way to increase the apparent interfacial toughness of brittle, thin-film material systems. The experimental portion of the study measured the interfacial toughness of a number of interfaces with nanoscale roughness. This included a silicon interface with a rectangular-toothed pattern of 60-nm wide by 90-nm deep channels fabricated using nanoimprint lithography techniques. Detailed finite element simulations were used to investigate the nature of interfacial crack growth when the interface is patterned. These simulations examined how geometric and material parameter choices affect the apparent toughness. Atomistic simulations were also performed with the aim of identifying possible modifications to the interfacial separation models currently used in nanoscale, finite element fracture analyses. The fundamental nature of atomistic traction separation for mixed mode loadings was investigated.

  7. Hybrid strategies for nanolithography and chemical patterning

    Science.gov (United States)

    Srinivasan, Charan

    Remarkable technological advances in photolithography have extended patterning to the sub-50-nm regime. However, because photolithography is a top-down approach, it faces substantial technological and economic challenges in maintaining the downward scaling trends of feature sizes below 30 nm. Concurrently, fundamental research on chemical self-assembly has enabled the path to access molecular length scales. The key to the success of photolithography is its inherent economies of scale, which justify the large capital investment for its implementation. In this thesis research, top-down and bottom-up approaches have been combined synergistically, and these hybrid strategies have been employed in applications that do not have the economies of scale found in semiconductor chip manufacturing. The specific instances of techniques developed here include molecular-ruler lithography and a series of nanoscale chemical patterning methods. Molecular-ruler lithography utilizes self-assembled multilayered films as a sidewall spacer on initial photolithographically patterned gold features (parent) to place a second-generation feature (daughter) in precise proximity to the parent. The parent-daughter separation, which is on the nanometer length scale, is defined by the thickness of the molecular-ruler resist. Analogous to protocols followed in industry to evaluate lithographic performance, electrical test-pad structures were designed to interrogate the nanostructures patterned by molecular-ruler nanolithography, failure modes creating electrical shorts were mapped to each lithographic step, and subsequent lithographic optimization was performed to pattern nanoscale devices with excellent electrical performance. The optimized lithographic processes were applied to generate nanoscale devices such as nanowires and thin-film transistors (TFTs). Metallic nanowires were patterned by depositing a tertiary generation material in the nanogap and surrounding micron-scale regions, and then

  8. Nanoscale patterns on micron-sized bubbles in foams

    Science.gov (United States)

    Dressaire, Emilie; Bell, David; Bee, Rodney; Lips, Alex; Stone, Howard

    2006-11-01

    The rheology and coarsening of foams is closely related to the microstructural characteristics of the small gas bubbles and their surface properties. We present experimental results of a foam formed upon shearing a mixture composed of glucose syrup and sucrose ester. Transmission Electron Microscopy reveals micron-size bubbles whose surfaces are fully covered with regular nanodimension, generally hexagonal, patterns. The influence of the shear rate during foam generation and the setting time on the development of the nanoscale patterns on the gas microcells are described. Plausible routes, driven by disproportionation of the gas from the small bubbles, for the formation of the nanoscale patterns are considered including a nucleation/crystallization pathway (Kim et al. 2003 Langmuir 19, p. 8455) and the buckling of an elastic insoluble surface film.

  9. Nanoscale 2.5-dimensional surface patterning with plasmonic lithography.

    Science.gov (United States)

    Jung, Howon; Park, Changhoon; Oh, Seonghyeon; Hahn, Jae W

    2017-08-29

    We report an extension of plasmonic lithography to nanoscale 2.5-dimensional (2.5D) surface patterning. To obtain the impulse response of a plasmonic lithography system, we described the field distribution of a point dipole source generated by a metallic ridge aperture with a theoretical model using the concepts of quasi-spherical waves and surface plasmon-polaritons. We performed deconvolution to construct an exposure map of a target shape for patterning. For practical applications, we fabricated several nanoscale and microscale structures, such as a cone, microlens array, nanoneedle, and a multiscale structure using the plasmonic lithography system. We verified the possibility of applying plasmonic lithography to multiscale structuring from a few tens of nanometres to a few micrometres in the lateral dimension. We obtained a root-mean-square error of 4.7 nm between the target shape and the patterned shape, and a surface roughness of 11.5 nm.

  10. Etching patterns on the micro‐ and nanoscale

    DEFF Research Database (Denmark)

    Michael-Lindhard, Jonas; Herstrøm, Berit; Stöhr, Frederik;

    2014-01-01

    in a liquid reacts with material from the substrate is the ability to fine‐tune the etch process. In wet processing the removal of material generally occurs indiscriminately of direction in the substrate ‐ hence in all directions. This puts a strong limitation on what may be achieved in terms of designs...... and polymer injection molding. High precision patterns of, for instance microfluidic devices, are etched intosilicon which is then electroplated with nickel that will serve as a stamp in the polymer injection molding tool where thousands of devices may be replicated. In addition to silicon and its derived...

  11. Modeling radiative properties of nanoscale patterned wafers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Temperature nonuniformity in rapid thermal processing of wafers is a critical problem facing the semiconductor industry. One cause of the problem is the nonuniform absorption of thermal radiation in patterned wafers where the optical properties vary across the wafer surface. This paper presents a parametric study of the radiative properties of patterned wafers, considering the effect of temperature, wavelength, and polarization. The finite-difference time-domain (FDTD) method is employed to examine the effect of various trench sizes on the radiative properties via numerically solving the Maxwell equations. The effective medium theory (EMT) is also used to help explain the absorptance prediction. The results show that in the cases with trench size variation, the resonance cavity effect may increase the absorptance as the trench width increases. And in the cases with trench size increasing at several different filling ratios, the absorptance does not change much at small filling ratio. The effects of the resonant cavity, diffraction, wave interferences on the spectral-directional absorptance were also discussed. This work is of great importance for optimization of advanced annealing techniques in semiconductor manufacturing.

  12. Microscopic Current Flow Patterns in Nanoscale Quantum Point Contacts

    Science.gov (United States)

    Sai, Na; Bushong, Neil; Hatcher, Ryan; di Ventra, Massimiliano

    2006-03-01

    Transport in nanoscale conductors has been studied extensively mainly using the stationary scattering approach. However, the dynamical nature of transport, and in particular, the flow patterns of the microscopic current through a nanoscale junction, have remained poorly understood. We apply a novel time-dependent transport approach [1], which combines closed and finite geometries with time-dependent density functional theory,to study current flow patterns in nanoscale quantum point contacts [2]. The results of both atomistic and jellium calculations show that surface charges form dynamically at the junction-electrode interfaces in both abrupt and adiabatic junctions. The curr ent exhibits some characteristics of a classical hydrodynamic liquid but also displays unique patterns arising from the interaction with the surface charges. We also investigate the effect of the flow velocity, charge density, and lattice structures on the electron dynamics. If time permits we also discuss the effects of the viscosity of the electron liquid [3]. Work supported by DOE (DE-FG02-05ER46204). [1] M. Di Ventra and T.N. Todorov, J. Phys. Cond. Matt. 16, 8025 (2004). [2] N. Bushong, N. Sai and, M. Di Ventra, Nano Lett. (in press). [3] N. Sai, M. Zwolak, G. Vignale, and M. Di Ventra, Phys. Rev. Lett. 94, 186810 (2005 ).

  13. Nanoscale domain patterns and a concept for an energy harvester

    Science.gov (United States)

    Renuka Balakrishna, Ananya; Huber, John E.

    2016-10-01

    The current work employs a phase-field model to test the stability of nanoscale periodic domain patterns, and to explore the application of one pattern in an energy harvester device. At first, the stability of several periodic domain patterns with in-plane polarizations is tested under stress-free and electric field-free conditions. It is found that simple domain patterns with stripe-like features are stable, while patterns with more complex domain configurations are typically unstable at the nanoscale. Upon identifying a stable domain pattern with suitable properties, a conceptual design of a thin film energy harvester device is explored. The harvester is modeled as a thin ferroelectric film bound to a substrate. In the initial state a periodic stripe domain pattern with zero net charge on the top electrode is modeled. On bending the substrate, a mechanical strain is induced in the film, causing polarized domains to undergo ferroelectric switching and thus generate electrical energy. The results demonstrate the working cycle of a conceptual energy harvester which, on operating at kHz frequencies, such as from vibrations in the environment, could produce an area power density of about 40 W m-2.

  14. Protein surface patterning using nanoscale PEG hydrogels.

    Science.gov (United States)

    Hong, Ye; Krsko, Peter; Libera, Matthew

    2004-12-01

    We have used focused electron-beam cross-linking to create nanosized hydrogels and thus present a new method with which to bring the attractive biocompatibility associated with macroscopic hydrogels into the submicron length-scale regime. Using amine-terminated poly(ethylene glycol) thin films on silicon substrates, we generate nanohydrogels with lateral dimensions of order 200 nm which can swell by a factor of at least five, depending on the radiative dose. With the focused electron beam, high-density arrays of such nanohydrogels can be flexibly patterned onto silicon surfaces. Significantly, the amine groups remain functional after e-beam exposure, and we show that they can be used to covalently bind proteins and other molecules. We use bovine serum albumin to amplify the number of amine groups, and we further demonstrate that different proteins can be covalently bound to different hydrogel pads on the same substrate to create multifunctional surfaces useful in emerging bio/proteomic and sensor technologies.

  15. Controlled isotropic or anisotropic nanoscale growth of coordination polymers: formation of hybrid coordination polymer particles.

    Science.gov (United States)

    Lee, Hee Jung; Cho, Yea Jin; Cho, Won; Oh, Moonhyun

    2013-01-22

    The ability to fabricate multicompositional hybrid materials in a precise and controlled manner is one of the primary goals of modern materials science research. In addition, an understanding of the phenomena associated with the systematic growth of one material on another can facilitate the evolution of multifunctional hybrid materials. Here, we demonstrate precise manipulation of the isotropic and/or anisotropic nanoscale growth of various coordination polymers (CPs) to obtain heterocompositional hybrid coordination polymer particles. Chemical composition analyses conducted at every growth step reveal the formation of accurately assembled hybrid nanoscale CPs, and microscopy images are used to examine the morphology of the particles and visualize the hybrid structures. The dissimilar growth behavior, that is, growth in an isotropic or anisotropic fashion, is found to be dependent on the size of the metal ions involved within the CPs.

  16. Hybrid lipids increase nanoscale fluctuation lifetimes in mixed membranes

    Science.gov (United States)

    Palmieri, Benoit; Safran, Samuel A.

    2013-09-01

    A recently proposed ternary mixture model is used to predict fluctuation domain lifetimes in the one phase region. The membrane is made of saturated, unsaturated, and hybrid lipids that have one saturated and one unsaturated hydrocarbon chain. The hybrid lipid is a natural linactant which can reduce the packing incompatibility between saturated and unsaturated lipids. The fluctuation lifetimes are predicted as a function of the hybrid lipid fraction and the fluctuation domain size. These lifetimes can be increased by up to three orders of magnitude compared to the case of no hybrids. With hybrid, small length scale fluctuations have sizable amplitudes even close to the critical temperature and, hence, benefit from enhanced critical slowing down. The increase in lifetime is particularly important for nanometer scale fluctuation domains where the hybrid orientation and the other lipids composition are highly coupled.

  17. Hybrid foundry patterns of bevel gears

    Directory of Open Access Journals (Sweden)

    Budzik G.

    2007-01-01

    Full Text Available Possibilities of making hybrid foundry patterns of bevel gears for investment casting process are presented. Rapid prototyping of gears with complex tooth forms is possible with the use of modern methods. One of such methods is the stereo-lithography, where a pattern is obtained as a result of resin curing with laser beam. Patterns of that type are applicable in precision casting. Removing of stereo-lithographic pattern from foundry mould requires use of high temperatures. Resin burning would generate significant amounts of harmful gases. In case of a solid stereo-lithographic pattern, the pressure created during gas burning may cause the mould to crack. A gas volume reduction may be achieved by using patterns of honeycomb structure. However, this technique causes a significant worsening of accuracy of stereo-lithographic patterns in respect of their dimensions and shape. In cooperation with WSK PZL Rzeszów, the Machine Design Department of Rzeszow University of Technology carried out research on the design of hybrid stereo-lithographic patterns. Hybrid pattern consists of a section made by stereo-lithographic process and a section made of casting wax. The latter material is used for stereo-lithographic pattern filling and for mould gating system. The hybrid pattern process consists of two stages: wax melting and then the burn-out of stereolithographic pattern. Use of hybrid patterns reduces the costs of production of stereolithographic patterns. High dimensional accuracy remains preserved in this process.

  18. E-beam-patterned hydrogels to control nanoscale surface bioactivity

    Science.gov (United States)

    Krsko, P.; Saaem, I.; Clancy, R.; Geller, H.; Soteropoulos, P.; Libera, M.

    2005-11-01

    We are interested in controlling the spatial distribution of proteins on surfaces at cellular and subcellular length scales. To do this, we use a variation of e-beam lithography in a field-emission scanning electron microscope (SEM) to radiation crosslink thin films of water- soluble polymers such as poly(ethylene glycol) [PEG] and poly (carboxylic acids). We can simultaneously pattern the resulting hydrogels on silicon or glass surfaces with nanoscale and microscale feature sizes. Using hydroxy-terminated PEG 6800 we create gels with swell ratios between unity and fifteen depending on the degree of radiation crosslinking, and the swelling properties can be interpreted in terms of the Flory-Rehner formulation modified for one-dimensional swelling. While lightly-crosslinked PEG gels resist protein adsorption and cell adhesion as expected, highly crosslinked PEG gels adsorb such proteins as fibronectin and laminin and consequently become adhesive to fibroblasts, macrophages, and neurons. By spatially modulating the degree of crosslinking, we can localize these cells on surfaces and, for example, direct neurite outgrowth. If instead of using hydroxy-terminated PEG we use amine- terminated PEG, we introduce the additional flexibility of creating high-swelling PEG gels that resist nonspecific protein adsorption but to which specific proteins can be covalently bound. These can be surface patterned at submicron spacings, and we can pattern 7500 nanohydrogels in a 100 micron diameter arrays in 10 seconds. This is an areal density ~104 times greater than a modern DNA/protein chip, and the required bioreagents for chip fabrication and processing are proportionately less. We can bind fibronectin and laminin to different arrays, and we show that these proteins maintain their biospecificity after binding to the nanohydrogels with high fidelity. Looking to applications in next-generation protein-chip technology, our most recent experiments compare the performance of nanohydrogel

  19. Nanoscale Structure of Self-Assembling Hybrid Materials of Inorganic and Electronically Active Organic Phases

    Energy Technology Data Exchange (ETDEWEB)

    Sofos, M.; Goswami, D.A. Stone D.K.; Okasinski, J.S.; Jin, H.; Bedzyk, M.J.; Stupp, S.I. (NWU)

    2008-10-06

    Hybrid materials with nanoscale structure that incorporates inorganic and organic phases with electronic properties offer potential in an extensive functional space that includes photovoltaics, light emission, and sensing. This work describes the nanoscale structure of model hybrid materials with phases of silica and electronically active bola-amphiphile assemblies containing either oligo(p-phenylene vinylene) or oligo(thiophene) segments. The hybrid materials studied here were synthesized by evaporation-induced self-assembly and characterized by X-ray scattering techniques. Grazing-incidence X-ray scattering studies of these materials revealed the formation of two-dimensional hexagonally packed cylindrical micelles of the organic molecules with diameters between 3.1 and 3.6 nm and cylindrical axes parallel to the surface. During the self-assembly process at low pH, the cylindrical aggregates of conjugated molecules become surrounded by silica giving rise to a hybrid structure with long-range order. Specular X-ray reflectivity confirmed the long-range periodicity of the hybrid films within a specific range of molar ratios of tetraethyl orthosilicate to cationic amphiphile. We did not observe any long-range ordering in fully organic analogues unless quaternary ammonium groups were replaced by tertiary amines. These observations suggest that charge screening in these biscationic conjugated molecules by the mineral phase is a key factor in the evolution of long range order in the self-assembling hybrids.

  20. Nonlocal effects in a hybrid plasmonic waveguide for nanoscale confinement.

    Science.gov (United States)

    Huang, Qiangsheng; Bao, Fanglin; He, Sailing

    2013-01-28

    The effect of nonlocal optical response is studied for a novel silicon hybrid plasmonic waveguide (HPW). Finite element method is used to implement the hydrodynamic model and the propagation mode is analyzed for a hybrid plasmonic waveguide of arbitrary cross section. The waveguide has an inverted metal nano-rib over a silicon-on-insulator (SOI) structure. An extremely small mode area of~10⁻⁶λ² is achieved together with several microns long propagation distance at the telecom wavelength of 1.55 μm. The figure of merit (FoM) is also improved in the same time, compared to the pervious hybrid plasmonic waveguide. We demonstrate the validity of our method by comparing our simulating results with some analytical results for a metal cylindrical waveguide and a metal slab waveguide in a wide wavelength range. For the HPW, we find that the nonlocal effects can give less loss and better confinement. In particular, we explore the influence of the radius of the rib's tip on the loss and the confinement. We show that the nonlocal effects give some new fundamental limitation on the confinement, leaving the mode area finite even for geometries with infinitely sharp tips.

  1. Hybrid Continuum and Molecular Modeling of Nano-scale Flows

    Science.gov (United States)

    Povitsky, Alex; Zhao, Shunliu

    2010-11-01

    A novel hybrid method combining the continuum approach based on boundary singularity method (BSM) and the molecular approach based on the direct simulation Monte Carlo (DSMC) is developed and then used to study viscous fibrous filtration flows in the transition flow regime, Kn>0.25. The DSMC is applied to a Knudsen layer enclosing the fiber and the BSM is employed to the entire flow domain. The parameters used in the DSMC and the coupling procedure, such as the number of simulated particles, the cell size and the size of the coupling zone are determined. Results are compared to the experiments measuring pressure drop and flowfield in filters. The optimal location of singularities outside of flow domain was determined and results are compared to those obtained by regularized Stokeslets. The developed hybrid method is parallelized by using MPI and extended to multi-fiber filtration flows. The multi-fiber filter flows considered are in the partial-slip and transition regimes. For Kn˜1, the computed velocity near fibers changes significantly that confirms the need of molecular methods in evaluation of the flow slip in transitional regime.

  2. METHOD FOR FABRICATING NANOSCALE PATTERNS ON A SURFACE

    DEFF Research Database (Denmark)

    2000-01-01

    A novel method to fabricate nanoscale pits on Au(111) surfaces in contact with aqueous solution is claimed. The method uses in situ electrochemical scanning tunnelling microscopy with independent electrochemical substrate and tip potential control and very small bias voltages. This is significantly...

  3. Nanoscale electrochemical patterning reveals the active sites for catechol oxidation at graphite surfaces.

    Science.gov (United States)

    Patel, Anisha N; McKelvey, Kim; Unwin, Patrick R

    2012-12-19

    Graphite-based electrodes (graphite, graphene, and nanotubes) are used widely in electrochemistry, and there is a long-standing view that graphite step edges are needed to catalyze many reactions, with the basal surface considered to be inert. In the present work, this model was tested directly for the first time using scanning electrochemical cell microscopy reactive patterning and shown to be incorrect. For the electro-oxidation of dopamine as a model process, the reaction rate was measured at high spatial resolution across a surface of highly oriented pyrolytic graphite. Oxidation products left behind in a pattern defined by the scanned electrochemical cell served as surface-site markers, allowing the electrochemical activity to be correlated directly with the graphite structure on the nanoscale. This process produced tens of thousands of electrochemical measurements at different locations across the basal surface, unambiguously revealing it to be highly electrochemically active, with step edges providing no enhanced activity. This new model of graphite electrodes has significant implications for the design of carbon-based biosensors, and the results are additionally important for understanding electrochemical processes on related sp(2)-hybridized materials such as pristine graphene and nanotubes.

  4. Nanoscale lamellar photoconductor hybrids and methods of making same

    Science.gov (United States)

    Stupp, Samuel I; Goldberger, Josh; Sofos, Marina

    2013-02-05

    An article of manufacture and methods of making same. In one embodiment, the article of manufacture has a plurality of zinc oxide layers substantially in parallel, wherein each zinc oxide layer has a thickness d.sub.1, and a plurality of organic molecule layers substantially in parallel, wherein each organic molecule layer has a thickness d.sub.2 and a plurality of molecules with a functional group that is bindable to zinc ions, wherein for every pair of neighboring zinc oxide layers, one of the plurality of organic molecule layers is positioned in between the pair of neighboring zinc oxide layers to allow the functional groups of the plurality of organic molecules to bind to zinc ions in the neighboring zinc oxide layers to form a lamellar hybrid structure with a geometric periodicity d.sub.1+d.sub.2, and wherein d.sub.1 and d.sub.2 satisfy the relationship of d.sub.1.ltoreq.d.sub.2.ltoreq.3d.sub.1.

  5. Energy and charge transfer in nanoscale hybrid materials.

    Science.gov (United States)

    Basché, Thomas; Bottin, Anne; Li, Chen; Müllen, Klaus; Kim, Jeong-Hee; Sohn, Byeong-Hyeok; Prabhakaran, Prem; Lee, Kwang-Sup

    2015-06-01

    Hybrid materials composed of colloidal semiconductor quantum dots and π-conjugated organic molecules and polymers have attracted continuous interest in recent years, because they may find applications in bio-sensing, photodetection, and photovoltaics. Fundamental processes occurring in these nanohybrids are light absorption and emission as well as energy and/or charge transfer between the components. For future applications it is mandatory to understand, control, and optimize the wide parameter space with respect to chemical assembly and the desired photophysical properties. Accordingly, different approaches to tackle this issue are described here. Simple organic dye molecules (Dye)/quantum dot (QD) conjugates are studied with stationary and time-resolved spectroscopy to address the dynamics of energy and ultra-fast charge transfer. Micellar as well as lamellar nanostructures derived from diblock copolymers are employed to fine-tune the energy transfer efficiency of QD donor/dye acceptor couples. Finally, the transport of charges through organic components coupled to the quantum dot surface is discussed with an emphasis on functional devices.

  6. Spray-coated nanoscale conductive patterns based on in situ sintered silver nanoparticle inks

    Science.gov (United States)

    2014-01-01

    Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 Ω /cm2 were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%. PMID:24666992

  7. Nanoscale Hybrid Langmuir-Blodgett Films Based on Cerium-Substituted Heteropolymolybdate and Polyquinoline

    Institute of Scientific and Technical Information of China (English)

    王峥; 柳士忠; 杜祖亮; 胡振纲; 张洪杰

    2003-01-01

    Nanoscale hybrid organic/inorganic Langmuir-Blodgett films of cerium-substituted heteropolymolybdates(Ce-HPMo) and π-conjugated macromolecule poly(1,2-dihydro-2,2,4-trimethyl)quinoline(PQ) were obtained with auxiliary film-forming material stearic acid(SA) or octadecylamine(ODA). The surface pressure-area isotherms illuminate the formation of the hybrid LB films of PQ/ODA/Ce-HPMo and P Q/SA/Ce-HPMo. The different film-forming mechanism was discussed when the different auxiliary film-forming materials were used in the system. The absorption spectra indicate that the molecules of PQ and Ce-HPMo are incorporated into the LB films. Tapping-mode AFM image reveals a granular surface texture of nanosized Ce-substituted heteropolymolybdate. STM image shows that the conductivity is greatly improved after Ce-substituted heteropolymolybdates are incorporated in the films.

  8. Interplay of Nanoscale, Hybrid P3HT/ZTO Interface on Optoelectronics and Photovoltaic Cells.

    Science.gov (United States)

    Lai, Jian-Jhong; Li, Yu-Hsun; Feng, Bo-Rui; Tang, Shiow-Jing; Jian, Wen-Bin; Fu, Chuan-Min; Chen, Jiun-Tai; Wang, Xu; Lee, Pooi-See

    2017-09-05

    Photovoltaic effects in poly(3-hexylthiophene-2,5-diyl) (P3HT) attract much attention recently. Here natively p-type doped P3HT nanofibers and n-type doped zinc tin oxide (ZTO) nanowires are used for making not only field-effect transistors but also p-n nanoscale diodes. The hybrid P3HT/ZTO p-n heterojunction shows applications in many directions and it also facilitates the investigation of photoelectrons and photovoltaic effects at the nanoscale. As for applications, the heterojunction device shows simultaneously high on/off ratio of n- and p-type field-effect transistors, gatable p-n junction diodes, tri-state buffer device, gatable photodetectors, and gatable solar cells. On the other hand, P3HT nanofibers are taken as a photoactive layer and the role of p-n heterojunction playing on the photoelectric and photovoltaic effects is investigated. It is found that the hybrid P3HT/ZTO p-n heterojunction assists to increase photocurrents and to enhance photovoltaic effects. Through the controllable gating of the heterojunction, we can discuss the background mechanisms of photocurrent generation and photovoltaic energy harvest.

  9. Viable chemical approach for patterning nanoscale magnetoresistive random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taeseung; Kim, Younghee; Chen, Jack Kun-Chieh; Chang, Jane P., E-mail: jpchang@seas.ucla.edu [Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2015-03-15

    A reactive ion etching process with alternating Cl{sub 2} and H{sub 2} exposures has been shown to chemically etch CoFe film that is an integral component in magnetoresistive random access memory (MRAM). Starting with systematic thermodynamic calculations assessing various chemistries and reaction pathways leading to the highest possible vapor pressure of the etch products reactions, the potential chemical combinations were verified by etch rate investigation and surface chemistry analysis in plasma treated CoFe films. An ∼20% enhancement in etch rate was observed with the alternating use of Cl{sub 2} and H{sub 2} plasmas, in comparison with the use of only Cl{sub 2} plasma. This chemical combination was effective in removing metal chloride layers, thus maintaining the desired magnetic properties of the CoFe films. Scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy showed visually and spectroscopically that the metal chloride layers generated by Cl{sub 2} plasma were eliminated with H{sub 2} plasma to yield a clean etch profile. This work suggests that the selected chemistries can be used to etch magnetic metal alloys with a smooth etch profile and this general strategy can be applied to design chemically based etch processes to enable the fabrication of highly integrated nanoscale MRAM devices.

  10. Nanoscale patterning in ambient conditions using liquid electromigration

    Science.gov (United States)

    Talukder, Santanu; Kumar, Praveen; Pratap, Rudra

    2016-04-01

    Electric field can induce long range flow in liquid materials. This phenomenon is known as liquid electromigration. In particular case of Cr thin film deposited on an insulating substrate, application of high electric-field between two point electrodes results in liquefaction and subsequent flow of the liquefied material in a radially symmetric fashion away from the cathode. This electric field driven material transport phenomenon has been used for a new patterning technique, named electrolithography. A negatively biased scanning probe is used to etch a thin Cr film according to a desired pattern. Then the pattern is transferred to new materials using a polymer layer below the metal film. Electrolithography does not need any UV or e-beam source, and can be performed in ambient condition. We have achieved pattern resolutions of 9 nm on the polymer and 40 nm on transferring the pattern to other materials. In this work, with the help of electrolithography, we have patterned large areas using vector scan technique. This improves throughput of the process by a significant order.

  11. Micro/nanoscale patterning of nanostructured metal substrates for plasmonic applications.

    Science.gov (United States)

    Shankar, S Shiv; Rizzello, Loris; Cingolani, Roberto; Rinaldi, Ross; Pompa, Pier Paolo

    2009-04-28

    The ability to precisely control the pattern of different metals at the micro- and nanoscale, along with their topology, has been demonstrated to be essential for many applications, ranging from material science to biomedical devices, electronics, and photonics. In this work, we show a novel approach, based on a combination of lithographic techniques and galvanic displacement reactions, to fabricate micro- and nanoscale patterns of different metals, with highly controlled surface roughness, onto a number of suitable substrates. We demonstrate the possibility to exploit such metal films to achieve significant fluorescence enhancement of nearby fluorophores, while maintaining accurate spatial control of the process, from submicron resolution to centimeter-sized features. These patterns may be also exploited for a wide range of applications, including SERS, solar cells, DNA microarray technology, hydrophobic/hydrophilic substrates, and magnetic devices.

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

    Science.gov (United States)

    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.

  13. Hybrid solar cells with prescribed nanoscale morphologies based on hyperbranched semiconductor nanocrystals.

    Science.gov (United States)

    Gur, Ilan; Fromer, Neil A; Chen, Chih-Ping; Kanaras, Antonios G; Alivisatos, A Paul

    2007-02-01

    In recent years, the search to develop large-area solar cells at low cost has led to research on photovoltaic (PV) systems based on nanocomposites containing conjugated polymers. These composite films can be synthesized and processed at lower costs and with greater versatility than the solid state inorganic semiconductors that comprise today's solar cells. However, the best nanocomposite solar cells are based on a complex architecture, consisting of a fine blend of interpenetrating and percolating donor and acceptor materials. Cell performance is strongly dependent on blend morphology, and solution-based fabrication techniques often result in uncontrolled and irreproducible blends, whose composite morphologies are difficult to characterize accurately. Here we incorporate three-dimensional hyperbranched colloidal semiconductor nanocrystals in solution-processed hybrid organic-inorganic solar cells, yielding reproducible and controlled nanoscale morphology.

  14. Hybrid bio-organic interfaces with matchable nanoscale topography for durable high extracellular electron transfer activity.

    Science.gov (United States)

    Ding, Chunmei; Liu, Huan; Lv, Meiling; Zhao, Tianyi; Zhu, Ying; Jiang, Lei

    2014-07-21

    Here, we developed a novel hybrid bio-organic interface with matchable nano-scale topography between a polypyrrole nanowire array (PPy-NA) and the bacterium Shewanella, which enabled a remarkably increased extracellular electron transfer (EET) current from genus Shewanella over a rather long period. PPy-NA thus exhibited outstanding performance in mediating bacterial EET, which was superior to normal electrodes such as carbon plates, Au and tin-doped In₂O₃. It was proposed that the combined effect of the inherent electrochemical nature of PPy and the porous structured bacterial network that was generated on the PPy-NA enabled long-term stability, while the high efficiency was attributed to the enhanced electron transfer rate between PPy-NA and microbes caused by the enhanced local topological interactions.

  15. Self-Replication of Nanoscale tiles and patterns

    Science.gov (United States)

    Chaikin, Paul

    2012-02-01

    We want to make a ``non-biological'' system which can self-replicate. The idea is to design particles with specific and reversible and irreversible interactions, introduce seed motifs, and cycle the system in such a way that a copy is made. Repeating the cycle would double the number of offspring in each generation leading to exponential growth. Using the chemistry of DNA either on colloids or on DNA tiles makes the specific recognition part easy. In the case of DNA tiles we have in fact replicated the seed at least to the third generation. The DNA linkers can also be self-protected so that particles don't interact unless they are held together for sufficient time -- a nano-contact glue. Chemical modification of the DNA allows us to permanently crosslink hybridized strands for irreversible bonds and a new type of photolithography. We have also designed and produced colloidal particles that use novel ``lock and key'' geometries to get specific and reversible physical interactions.[4pt] With Tong Wang, Ruojie Sha, Remi Dreyfus, Mirjam E. Leunissen, Corinna Maass, David J. Pine, and Nadrian C. Seeman.

  16. Nanoscale programmable sequence-specific patterning of DNA scaffolds using RecA protein

    Science.gov (United States)

    Sharma, R.; Davies, A. G.; Wälti, C.

    2012-09-01

    Molecular self-assembly inherent to many biological molecules, in conjunction with suitable molecular scaffolds to facilitate programmable positioning of nanoscale objects, offers a promising approach for the integration of functional nanoscale complexes into macroscopic host devices. Here, we report the use of the protein RecA as a means of highly efficient programmable patterning of double-stranded (ds)DNA molecules with molecular-scale precision at specific locations along the DNA strand. RecA proteins form nucleoprotein filaments with single-stranded (ss)DNA molecules, which are chosen to be of sequence homologous to the desired binding region on the dsDNA scaffold. We show that the patterning yield can be in excess of 85% and we demonstrate that concurrent patterning of multiple locations on the same dsDNA scaffold can be achieved with separation between the assembled nucleoprotein filaments of less than 4 nm. This is an important prerequisite for this programmable and flexible DNA scaffold patterning technique to be employed in molecular- and nanoscale assembly applications.

  17. Ordered nano-scale dimple pattern formation on a titanium alloy (Ti-6Al-4V)

    OpenAIRE

    Yue Wang; Sherdeep Singh; Peter Kruse

    2012-01-01

    Due to the many applications of nanostructured surfaces – including in biomaterials – there is a strong interest in cost- and time-efficient methods for their fabrication. Previously, our group established a simple electrochemical method generating nanoscale patterns on large areas of a number of different metal surfaces. They consist of dimples that are around 6-10 nm deep and hexagonally closed packed with a tunable periodicity of around 50 nm. Ordering requires careful tuning of the surfac...

  18. Nanoscale Patterning of Antigen on Silicon Substrate to Examine Mast Cell Activation

    Science.gov (United States)

    2002-04-01

    Examine Mast Cell Activation DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the following report: TITLE...Materials Research Society N4.3 Nanoscale Patterning of Antigen on Silicon Substrate to Examine Mast Cell Activation Reid N. Orth", Min Wu2 , Theodore G...nanometer scale to spatially control the stimulation of specific immunoreceptors on RBL mast cells . This work was motivated by previous research to

  19. Fabrication of ordered micro- and nano-scale patterns based on optical discs and nanoimprint

    Science.gov (United States)

    Guo, Hui-jing; Zhang, Xiao-liang; Li, Xiao-chun

    2016-07-01

    A simple method to fabricate one-dimensional (1-D) and two-dimensional (2-D) ordered micro- and nano-scale patterns is developed based on the original masters from optical discs, using nanoimprint technology and soft stamps. Polydimethylsiloxane (PDMS) was used to replicate the negative image of the 1-D grating pattern on the masters of CD-R, DVD-R and BD-R optical discs, respectively, and then the 1-D pattern on one of the PDMS stamps was transferred to a blank polycarbonate (PC) substrate by nanoimprint. The 2-D ordered patterns were fabricated by the second imprinting using another PDMS stamp. Different 2-D periodic patterns were obtained depending on the PDMS stamps and the angle between the two times of imprints. This method may provide a way for the fabrication of complex 2-D patterns using simple 1-D masters.

  20. Micro-and/or nano-scale patterned porous membranes, methods of making membranes, and methods of using membranes

    KAUST Repository

    Wang, Xianbin

    2015-01-22

    Embodiments of the present disclosure provide for materials that include a pre-designed patterned, porous membrane (e.g., micro- and/or nano-scale patterned), structures or devices that include a pre-designed patterned, porous membrane, methods of making pre-designed patterned, porous membranes, methods of separation, and the like.

  1. Reversed Nanoscale Kirkendall Effect in Au–InAs Hybrid Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing; Amit, Yorai; Li, Yuanyuan; Plonka, Anna M.; Ghose, Sanjit; Zhang, Lihua; Stach, Eric A.; Banin, Uri; Frenkel, Anatoly I. (Yeshiva); (BNL); (Hebrew); (SBU)

    2016-11-08

    Metal–semiconductor hybrid nanoparticles (NPs) offer interesting synergistic properties, leading to unique behaviors that have already been exploited in photocatalysis, electrical, and optoelectronic applications. A fundamental aspect in the synthesis of metal–semiconductor hybrid NPs is the possible diffusion of the metal species through the semiconductor lattice. The importance of understanding and controlling the co-diffusion of different constituents is demonstrated in the synthesis of various hollow-structured NPs via the Kirkendall effect. Here, we used a postsynthesis room-temperature reaction between AuCl3 and InAs nanocrystals (NCs) to form metal–semiconductor core–shell hybrid NPs through the “reversed Kirkendall effect”. In the presented system, the diffusion rate of the inward diffusing species (Au) is faster than that of the outward diffusing species (InAs), which results in the formation of a crystalline metallic Au core surrounded by an amorphous, oxidized InAs shell containing nanoscale voids. We used time-resolved X-ray absorption fine-structure (XAFS) spectroscopy to monitor the diffusion process and found that both the size of the Au core and the extent of the disorder of the InAs shell depend strongly on the Au-to-NC ratio. We have determined, based on multielement fit analysis, that Au diffuses into the NC via the kick-out mechanism, substituting for In host atoms; this compromises the structural stability of the lattice and triggers the formation of In–O bonds. These bonds were used as markers to follow the diffusion process and indicate the extent of degradation of the NC lattice. Time-resolved X-ray diffraction (XRD) was used to measure the changes in the crystal structures of InAs and the nanoscale Au phases. By combining the results of XAFS, XRD, and electron microscopy, we correlated the changes in the local structure around Au, As, and In atoms and the changes in the overall InAs crystal structure. This

  2. Nanoscale conductive pattern of the homoepitaxial AlGaN/GaN transistor.

    Science.gov (United States)

    Pérez-Tomás, A; Catalàn, G; Fontserè, A; Iglesias, V; Chen, H; Gammon, P M; Jennings, M R; Thomas, M; Fisher, C A; Sharma, Y K; Placidi, M; Chmielowska, M; Chenot, S; Porti, M; Nafría, M; Cordier, Y

    2015-03-20

    The gallium nitride (GaN)-based buffer/barrier mode of growth and morphology, the transistor electrical response (25-310 °C) and the nanoscale pattern of a homoepitaxial AlGaN/GaN high electron mobility transistor (HEMT) have been investigated at the micro and nanoscale. The low channel sheet resistance and the enhanced heat dissipation allow a highly conductive HEMT transistor (Ids > 1 A mm(-1)) to be defined (0.5 A mm(-1) at 300 °C). The vertical breakdown voltage has been determined to be ∼850 V with the vertical drain-bulk (or gate-bulk) current following the hopping mechanism, with an activation energy of 350 meV. The conductive atomic force microscopy nanoscale current pattern does not unequivocally follow the molecular beam epitaxy AlGaN/GaN morphology but it suggests that the FS-GaN substrate presents a series of preferential conductive spots (conductive patches). Both the estimated patches density and the apparent random distribution appear to correlate with the edge-pit dislocations observed via cathodoluminescence. The sub-surface edge-pit dislocations originating in the FS-GaN substrate result in barrier height inhomogeneity within the HEMT Schottky gate producing a subthreshold current.

  3. Quantum mechanical modeling the emission pattern and polarization of nanoscale light emitting diodes.

    Science.gov (United States)

    Wang, Rulin; Zhang, Yu; Bi, Fuzhen; Frauenheim, Thomas; Chen, GuanHua; Yam, ChiYung

    2016-07-21

    Understanding of the electroluminescence (EL) mechanism in optoelectronic devices is imperative for further optimization of their efficiency and effectiveness. Here, a quantum mechanical approach is formulated for modeling the EL processes in nanoscale light emitting diodes (LED). Based on non-equilibrium Green's function quantum transport equations, interactions with the electromagnetic vacuum environment are included to describe electrically driven light emission in the devices. The presented framework is illustrated by numerical simulations of a silicon nanowire LED device. EL spectra of the nanowire device under different bias voltages are obtained and, more importantly, the radiation pattern and polarization of optical emission can be determined using the current approach. This work is an important step forward towards atomistic quantum mechanical modeling of the electrically induced optical response in nanoscale systems.

  4. Periodic nanoscale patterning of polyelectrolytes over square centimeter areas using block copolymer templates.

    Science.gov (United States)

    Oded, Meirav; Kelly, Stephen T; Gilles, Mary K; Müller, Axel H E; Shenhar, Roy

    2016-05-18

    Nano-patterned materials are beneficial for applications such as solar cells, opto-electronics, and sensing owing to their periodic structure and high interfacial area. Here, we present a non-lithographic approach for assembling polyelectrolytes into periodic nanoscale patterns over cm(2)-scale areas. Chemically modified block copolymer thin films featuring alternating charged and neutral domains are used as patterned substrates for electrostatic self-assembly. In-depth characterization of the deposition process using spectroscopy and microscopy techniques, including the state-of-the-art scanning transmission X-ray microscopy (STXM), reveals both the selective deposition of the polyelectrolyte on the charged copolymer domains as well as gradual changes in the film topography that arise from further penetration of the solvent molecules and possibly also the polyelectrolyte into these domains. Our results demonstrate the feasibility of creating nano-patterned polyelectrolyte layers, which opens up new opportunities for structured functional coating fabrication.

  5. Probing nanoscale chemical segregation and surface properties of antifouling hybrid xerogel films.

    Science.gov (United States)

    Destino, Joel F; Gatley, Caitlyn M; Craft, Andrew K; Detty, Michael R; Bright, Frank V

    2015-03-24

    Over the past decade there has been significant development in hybrid polymer coatings exhibiting tunable surface morphology, surface charge, and chemical segregation-all believed to be key properties in antifouling (AF) coating performance. While a large body of research exists on these materials, there have yet to be studies on all the aforementioned properties in a colocalized manner with nanoscale spatial resolution. Here, we report colocalized atomic force microscopy, scanning Kelvin probe microscopy, and confocal Raman microscopy on a model AF xerogel film composed of 1:9:9 (mol:mol:mol) 3-aminopropyltriethoxysilane (APTES), n-octyltriethoxysilane (C8), and tetraethoxysilane (TEOS) formed on Al2O3. This AF film is found to consist of three regions that are chemically and physically unique in 2D and 3D across multiple length scales: (i) a 1.5 μm thick base layer derived from all three precursors; (ii) 2-4 μm diameter mesa-like features that are enriched in free amine (from APTES), depleted in the other species and that extend 150-400 nm above the base layer; and (iii) 1-2 μm diameter subsurface inclusions within the base layer that are enriched in hydrogen-bonded amine (from APTES) and depleted in the other species.

  6. Enhancement of Water Evaporation on Solid Surfaces with Nanoscale Hydrophobic-Hydrophilic Patterns.

    Science.gov (United States)

    Wan, Rongzheng; Wang, Chunlei; Lei, Xiaoling; Zhou, Guoquan; Fang, Haiping

    2015-11-06

    Using molecular dynamics simulations, we show that the evaporation of nanoscale water on hydrophobic-hydrophilic patterned surfaces is unexpectedly faster than that on any surfaces with uniform wettability. The key to this phenomenon is that, on the patterned surface, the evaporation rate from the hydrophilic region only slightly decreases due to the correspondingly increased water thickness; meanwhile, a considerable number of water molecules evaporate from the hydrophobic region despite the lack of water film. Most of the evaporated water from the hydrophobic region originates from the hydrophilic region by diffusing across the contact lines. Further analysis shows that the evaporation rate from the hydrophobic region is approximately proportional to the total length of the contact lines.

  7. Thermal analysis of continuous and patterned multilayer films in the presence of a nanoscale hot spot

    Science.gov (United States)

    Juang, Jia-Yang; Zheng, Jinglin

    2016-10-01

    Thermal responses of multilayer films play essential roles in state-of-the-art electronic systems, such as photo/micro-electronic devices, data storage systems, and silicon-on-insulator transistors. In this paper, we focus on the thermal aspects of multilayer films in the presence of a nanoscale hot spot induced by near field laser heating. The problem is set up in the scenario of heat assisted magnetic recording (HAMR), the next-generation technology to overcome the data storage density limit imposed by superparamagnetism. We characterized thermal responses of both continuous and patterned multilayer media films using transient thermal modeling. We observed that material configurations, in particular, the thermal barriers at the material layer interfaces crucially impact the temperature field hence play a key role in determining the hot spot geometry, transient response and power consumption. With a representative generic media model, we further explored the possibility of optimizing thermal performances by designing layers of heat sink and thermal barrier. The modeling approach demonstrates an effective way to characterize thermal behaviors of micro and nano-scale electronic devices with multilayer thin film structures. The insights into the thermal transport scheme will be critical for design and operations of such electronic devices.

  8. Thermal analysis of continuous and patterned multilayer films in the presence of a nanoscale hot spot

    Directory of Open Access Journals (Sweden)

    Jia-Yang Juang

    2016-10-01

    Full Text Available Thermal responses of multilayer films play essential roles in state-of-the-art electronic systems, such as photo/micro-electronic devices, data storage systems, and silicon-on-insulator transistors. In this paper, we focus on the thermal aspects of multilayer films in the presence of a nanoscale hot spot induced by near field laser heating. The problem is set up in the scenario of heat assisted magnetic recording (HAMR, the next-generation technology to overcome the data storage density limit imposed by superparamagnetism. We characterized thermal responses of both continuous and patterned multilayer media films using transient thermal modeling. We observed that material configurations, in particular, the thermal barriers at the material layer interfaces crucially impact the temperature field hence play a key role in determining the hot spot geometry, transient response and power consumption. With a representative generic media model, we further explored the possibility of optimizing thermal performances by designing layers of heat sink and thermal barrier. The modeling approach demonstrates an effective way to characterize thermal behaviors of micro and nano-scale electronic devices with multilayer thin film structures. The insights into the thermal transport scheme will be critical for design and operations of such electronic devices.

  9. Stimuli responsive polymer/quantum dot hybrid platforms modified at the nanoscale

    NARCIS (Netherlands)

    Tagit, Oya

    2010-01-01

    Quantum dots, QDs, receive growing attention from many research disciplines owing to their advantages as fluorescent probes including their nanoscale size (similar to biomolecules), high quantum yield and molar extinction coefficients, versatility in surface modification, broad excitation spectra (f

  10. Approach to tune near- and far-field properties of hybrid dimer nanoantennas via laser melting at the nanoscale

    CERN Document Server

    Sun, Yali; Zuev, Dmitry; Huang, Lirong; Krasnok, Alexander; Belov, Pavel

    2016-01-01

    Asymmetric metal-dielectric nanostructures are demonstrated superior optical properties arise from the combination of strong enhancement of their near fields and controllable scattering characteristics which originate from plasmonic and high-index dielectric components. Here, being inspired by the recent experimental work [Dmitry~Zuev, \\textit{et al.}, Adv. Mater. \\textbf{28}, 3087 (2016)] on a new technique for fabrication of asymmetric hybrid nanoparticles via femtosecond laser melting at the nanoscale, we suggest and study numerically a novel type of hybrid dimer nanoantennas. The nanoantennas consist of asymmetric metal-dielectric (Au/Si) nanoparticles and can allow tuning of the near- and far-field properties via laser melting of the metal part. We demonstrate a modification of scattering properties, near electric field distribution, normalized local density of states, and power patters of radiation of the nanoantennas upon laser reshaping. The parameters used to investigate these effects correspond to e...

  11. Cracking-assisted fabrication of nanoscale patterns for micro/nanotechnological applications.

    Science.gov (United States)

    Kim, Minseok; Kim, Dong-Joo; Ha, Dogyeong; Kim, Taesung

    2016-05-01

    Cracks are frequently observed in daily life, but they are rarely welcome and are considered as a material failure mode. Interestingly, cracks cause critical problems in various micro/nanofabrication processes such as colloidal assembly, thin film deposition, and even standard photolithography because they are hard to avoid or control. However, increasing attention has been given recently to control and use cracks as a facile, low-cost strategy for producing highly ordered nanopatterns. Specifically, cracking is the breakage of molecular bonds and occurs simultaneously over a large area, enabling fabrication of nanoscale patterns at both high resolution and high throughput, which are difficult to obtain simultaneously using conventional nanofabrication techniques. In this review, we discuss various cracking-assisted nanofabrication techniques, referred to as crack lithography, and summarize the fabrication principles, procedures, and characteristics of the crack patterns such as their position, direction, and dimensions. First, we categorize crack lithography techniques into three technical development levels according to the directional freedom of the crack patterns: randomly oriented, unidirectional, or multidirectional. Then, we describe a wide range of novel practical devices fabricated by crack lithography, including bioassay platforms, nanofluidic devices, nanowire sensors, and even biomimetic mechanosensors.

  12. Cracking-assisted fabrication of nanoscale patterns for micro/nanotechnological applications

    Science.gov (United States)

    Kim, Minseok; Kim, Dong-Joo; Ha, Dogyeong; Kim, Taesung

    2016-05-01

    Cracks are frequently observed in daily life, but they are rarely welcome and are considered as a material failure mode. Interestingly, cracks cause critical problems in various micro/nanofabrication processes such as colloidal assembly, thin film deposition, and even standard photolithography because they are hard to avoid or control. However, increasing attention has been given recently to control and use cracks as a facile, low-cost strategy for producing highly ordered nanopatterns. Specifically, cracking is the breakage of molecular bonds and occurs simultaneously over a large area, enabling fabrication of nanoscale patterns at both high resolution and high throughput, which are difficult to obtain simultaneously using conventional nanofabrication techniques. In this review, we discuss various cracking-assisted nanofabrication techniques, referred to as crack lithography, and summarize the fabrication principles, procedures, and characteristics of the crack patterns such as their position, direction, and dimensions. First, we categorize crack lithography techniques into three technical development levels according to the directional freedom of the crack patterns: randomly oriented, unidirectional, or multidirectional. Then, we describe a wide range of novel practical devices fabricated by crack lithography, including bioassay platforms, nanofluidic devices, nanowire sensors, and even biomimetic mechanosensors.

  13. Manipulating Fano resonance via fs-laser melting of hybrid oligomers at nanoscale

    Science.gov (United States)

    Lepeshov, S. I.; Zuev, D. A.; Makarov, S. V.; Milichko, V. A.; Mukhin, I. S.; Krasnok, A. E.; Belov, P. A.

    2016-08-01

    Here, the novel concept of asymmetric metal-dielectric (hybrid) nanoparticles is proposed. The experimental data and the results of numerical simulation of the optical properties of hybrid nanostructures are presented. The change of their optical response after fs- laser modification is shown. The possibility of manipulating Fano resonance in hybrid oligomers by the gold nanoparticles reshaping is demonstrated.

  14. Ordered nano-scale dimple pattern formation on a titanium alloy (Ti-6Al-4V

    Directory of Open Access Journals (Sweden)

    Yue Wang

    2012-09-01

    Full Text Available Due to the many applications of nanostructured surfaces – including in biomaterials – there is a strong interest in cost- and time-efficient methods for their fabrication. Previously, our group established a simple electrochemical method generating nanoscale patterns on large areas of a number of different metal surfaces. They consist of dimples that are around 6-10 nm deep and hexagonally closed packed with a tunable periodicity of around 50 nm. Ordering requires careful tuning of the surface chemistry, which makes the translation of these findings to multi-component alloys non-obvious. Here, we demonstrate for the first time that such a pattern can also be achieved on the surface of an alloy, namely Ti-6Al-4V. This alloy is of particular interest for biomedical implants. While dimple formation on the main component metals titanium and aluminum has previously been reported (albeit under conditions that differ from each other, we now also report dimple formation on pure vanadium surfaces to occur under very different conditions. Dimple formation occurs preferentially on the (dominant α-phase grains of the alloy. The size of dimples of the alloy material is subject to the electropolishing potential, electrolyte concentration and surface chemical composition, which gives us the opportunity to control the surface features. Since a main application of this alloy are biomedical implants, this level of control will be an important tool for accommodating cell growth.

  15. Characterization of a nanoscale S-layer protein based template for biomolecular patterning.

    Science.gov (United States)

    Wong, Wing Sze; Yung, Pun To

    2014-01-01

    Well organized template for biomolecular conjugation is the foundation for biosensing. Most of the current devices are fabricated using lithographic patterning processes and self-assembly monolayer (SAM) methods. However, the research toward developing a sub-10 nm patterned, self-regenerated template on various types of substrates is limited, mainly due to the limited functional groups of the building material. Bacterial surface layer proteins (S-layer proteins) can self-assemble into ordered lattice with regular pore sizes of 2-8 nm on different material supports and interfaces. The ordered structure can regenerate after extreme variations of solvent conditions. In this work, we developed a nanoscale biomolecular template based on S-layer proteins on gold surface for fabrication of sensing layer in biosensors. S-layer proteins were isolated from Bacillus cereus, Lysinibacillus sphaericus and Geobacillus stearothermophilus. Protein concentrations were measured by Bradford assay. The protein purities were verified by SDS-PAGE, showing molecular weights ranging from 97-135 kDa. The hydrophilicity of the substrate surface was measured after surface treatments of protein recrystallization. Atomic force microscopic (AFM) measurement was performed on substrate surface, indicating a successful immobilization of a monolayer of S-layer protein with 8-9 nm height on gold surface. The template can be applied on various material supports and acts as a self-regenerated sensing layer of biosensors in the future.

  16. Quasicontinuum simulations of geometric effect on onset plasticity of nano-scale patterned lines

    Science.gov (United States)

    Jin, Jianfeng; Cao, Jingyi; Zhou, Siyuan; Yang, Peijun; Guo, Zhengxiao

    2017-09-01

    Onset plasticity of metallic nano-lines or nano-beams is of considerable scientific and technological interest in micro-/nano- mechanics and interconnects of patterned lines in electronic devices, where capability of resistance to deformation is important. In this study, a multiscale quasicontinuum (QC) method was used to explore such an issue in a nano-scale copper (Cu) line protruding from a relatively large single crystal Cu substrate during compression. The results show that the yield stress of a rectangular beam on the substrate can be greatly reduced compared with that of a flat surface of the same area. For the rectangular line, the aspect ratio (width/height) affects dislocation morphology at the onset plasticity without much change of yield stress. However, for the trapezoidal line, the yield stress decreases with the base angle (α), especially when the α is over 54.7°. As the sidewall orientation changes from at α = 0°, then to at α = 54.7° and finally to at α = 90°, a higher surface energy could enable easier dislocation formation and lower yield stress. Meanwhile, it is found that the interaction between the line and the support substrate also shows a great effect on yield stress. Moreover, although it is possible to open two extra dislocation slip planes inside from the two bottom corners of the Cu line with the α over 54.7°, dislocation nucleation derived from them is only observed at α = 90°.

  17. Poly(3-hexylthiophene)/multiwalled carbon hybrid coaxial nanotubes: nanoscale rectification and photovoltaic characteristics.

    Science.gov (United States)

    Kim, Kihyun; Shin, Ji Won; Lee, Yong Baek; Cho, Mi Yeon; Lee, Suk Ho; Park, Dong Hyuk; Jang, Dong Kyu; Lee, Cheol Jin; Joo, Jinsoo

    2010-07-27

    We fabricate hybrid coaxial nanotubes (NTs) of multiwalled carbon nanotubes (MWCNTs) coated with light-emitting poly(3-hexylthiophene) (P3HT). The p-type P3HT material with a thickness of approximately 20 nm is electrochemically deposited onto the surface of the MWCNT. The formation of hybrid coaxial NTs of the P3HT/MWCNT is confirmed by a transmission electron microscope, FT-IR, and Raman spectra. The optical and structural properties of the hybrid NTs are characterized using ultraviolet and visible absorption, Raman, and photoluminescence (PL) spectra where, it is shown that the PL intensity of the P3HT materials decreases after the hybridization with the MWCNTs. The current-voltage (I-V) characteristics of the outer P3HT single NT show the semiconducting behavior, while ohmic behavior is observed for the inner single MWCNT. The I-V characteristics of the hybrid junction between the outer P3HT NT and the inner MWCNT, for the hybrid single NT, exhibit the characteristics of a diode (i.e., rectification), whose efficiency is clearly enhanced with light irradiation. The rectification effect of the hybrid single NT has been analyzed in terms of charge tunneling models. The quasi-photovoltaic effect is also observed at low bias for the P3HT/MWCNT hybrid single NT.

  18. Lipid-peptide vesicle nanoscale hybrids for triggered drug release by mild hyperthermia in vitro and in vivo.

    Science.gov (United States)

    Al-Ahmady, Zahraa S; Al-Jamal, Wafa' T; Bossche, Jeroen V; Bui, Tam T; Drake, Alex F; Mason, A James; Kostarelos, Kostas

    2012-10-23

    The present study describes leucine zipper peptide-lipid hybrid nanoscale vesicles engineered by self-assembled anchoring of the amphiphilic peptide within the lipid bilayer. These hybrid vesicles aim to combine the advantages of traditional temperature-sensitive liposomes (TSL) with the dissociative, unfolding properties of a temperature-sensitive peptide to optimize drug release under mild hyperthermia, while improving in vivo drug retention. The secondary structure of the peptide and its thermal responsiveness after anchoring onto liposomes were studied with circular dichroism. In addition, the lipid-peptide vesicles (Lp-peptide) showed a reduction in bilayer fluidity at the inner core, as observed with DPH anisotropy studies, while the opposite effect was observed with an ANS probe, indicating peptide interactions with both the headgroup region and the hydrophobic core. A model drug molecule, doxorubicin, was successfully encapsulated in the Lp-peptide vesicles at higher than 90% efficiency following the remote loading, pH-gradient methodology. The release of doxorubicin from Lp-peptide hybrids in vitro indicated superior serum stability at physiological temperatures compared to lysolipid-containing temperature-sensitive liposomes (LTSL) without affecting the overall thermo-responsive nature of the vesicles at 42 °C. A similar stabilizing effect was observed in vivo after intravenous administration of the Lp-peptide vesicles by measuring (14)C-doxorubicin blood kinetics that also led to increased tumor accumulation after 24 h. We conclude that Lp-peptide hybrid vesicles present a promising new class of TSL that can offer previously unexplored opportunities for the development of clinically relevant mild hyperthermia-triggered therapeutic modalities.

  19. Towards hybrid quantum systems: Trapping a single atom near a nanoscale solid-state structure

    Directory of Open Access Journals (Sweden)

    Tiecke T.G.

    2013-08-01

    Full Text Available We describe and demonstrate a method to deterministically trap single atoms near nanoscale solid-state objects. The trap is formed by the interference of an optical tweezer and its reflection from the nano object, creating a one-dimensional optical lattice where the first lattice site is at z0 ∼ λ/4 from the surface. Using a tapered optical fiber as the nanoscopic object, we characterize the loading into different lattice sites by means of the AC-Stark shift induced by a guided fiber mode. We demonstrate a loading efficiency of 94(6% into the first lattice site, and measure the cooperativity for the emission of the atom into the guided mode of the nanofiber. We show that by tailoring the dimensions of the nanofiber the distance of the trap to the surface can be adjusted. This method is applicable to a large variety of nanostructures and represents a promising starting point for interfacing single atoms with arbitrary nanoscale solid-state systems.

  20. Exchange-coupled nanoscale SmCo/NdFeB hybrid magnets

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dapeng; Poudyal, Narayan; Rong, Chuanbing; Zhang, Ying; Kramer, Matthew J.; Liu, J. Ping

    2012-05-11

    Nanoscalehybridmagnets containing SmCo5 and Nd2Fe14B hard magnetic phases have been produced via a novel “in-one-pot” processing route. The grain size of the processed bulk composite materials is controlled below 20 nm. The refinement of the nanoscale morphology leads to effective inter-phase exchange coupling that results in single-phase like magnetic properties. Energy product of 14 MGOe was obtained in the isotropic nanocomposite magnets at room temperature. At elevated temperatures, the hybridmagnets have greatly improved thermal stability compared to the Nd2Fe14B single-phase counterpart and have substantially increased magnetization and energy products compared to the single-phase SmCo5 counterpart.

  1. An Efficient Hybrid Algorithm for Mining Web Frequent Access Patterns

    Institute of Scientific and Technical Information of China (English)

    ZHAN Li-qiang; LIU Da-xin

    2004-01-01

    We propose an efficient hybrid algorithm WDHP in this paper for mining frequent access patterns.WDHP adopts the techniques of DHP to optimize its performance, which is using hash table to filter candidate set and trimming database.Whenever the database is trimmed to a size less than a specified threshold, the algorithm puts the database into main memory by constructing a tree, and finds frequent patterns on the tree.The experiment shows that WDHP outperform algorithm DHP and main memory based algorithm WAP in execution efficiency.

  2. Beam Pattern Synthesis Based on Hybrid Optimization Algorithm

    Institute of Scientific and Technical Information of China (English)

    YU Yan-li; WANG Ying-min; LI Lei

    2010-01-01

    As conventional methods for beam pattern synthesis can not always obtain the desired optimum pattern for the arbitrary underwater acoustic sensor arrays, a hybrid numerical synthesis method based on adaptive principle and genetic algorithm was presented in this paper. First, based on the adaptive theory, a given array was supposed as an adaptive array and its sidelobes were reduced by assigning a number of interference signals in the sidelobe region. An initial beam pattern was obtained after several iterations and adjustments of the interference intensity, and based on its parameters, a desired pattern was created. Then, an objective function based on the difference between the designed and desired patterns can be constructed. The pattern can be optimized by using the genetic algorithm to minimize the objective function. A design example for a double-circular array demonstrates the effectiveness of this method. Compared with the approaches existing before, the proposed method can reduce the sidelobe effectively and achieve less synthesis magnitude error in the mainlobe.The method can search for optimum attainable pattern for the specific elements if the desired pattern can not be found.

  3. Multiway study of hybridization in nanoscale semiconductor labeled DNA based on fluorescence resonance energy transfer

    DEFF Research Database (Denmark)

    Gholami, Somayeh; Kompany Zare, Mohsen

    2013-01-01

    The resolution of the ternary-binary complex competition of a target sequence and of its two complementary probes in sandwich DNA hybridization is reported. To achieve this goal, Fluorescence Resonance Energy Transfer (FRET) between oligonucleotide-functionalized quantum dot (QD) nanoprobes (QD...... in the photoluminescence excitation (PLE) plot. From the obtained data, energy transfer efficiency and Forster radius (R-0) were calculated. In particular, our results demonstrated that energy transfer by using QD donor-QD acceptor FRET pairs is more efficient in comparison with QD donor-organic dye acceptor pairs. Soft...

  4. Exposure to nanoscale particles and fibers during machining of hybrid advanced composites containing carbon nanotubes

    Science.gov (United States)

    Bello, Dhimiter; Wardle, Brian L.; Yamamoto, Namiko; Guzman deVilloria, Roberto; Garcia, Enrique J.; Hart, Anastasios J.; Ahn, Kwangseog; Ellenbecker, Michael J.; Hallock, Marilyn

    2009-01-01

    This study investigated airborne exposures to nanoscale particles and fibers generated during dry and wet abrasive machining of two three-phase advanced composite systems containing carbon nanotubes (CNTs), micron-diameter continuous fibers (carbon or alumina), and thermoset polymer matrices. Exposures were evaluated with a suite of complementary instruments, including real-time particle number concentration and size distribution (0.005-20 μm), electron microscopy, and integrated sampling for fibers and respirable particulate at the source and breathing zone of the operator. Wet cutting, the usual procedure for such composites, did not produce exposures significantly different than background whereas dry cutting, without any emissions controls, provided a worst-case exposure and this article focuses here. Overall particle release levels, peaks in the size distribution of the particles, and surface area of released particles (including size distribution) were not significantly different for composites with and without CNTs. The majority of released particle surface area originated from the respirable (1-10 μm) fraction, whereas the nano fraction contributed 10% of the surface area. CNTs, either individual or in bundles, were not observed in extensive electron microscopy of collected samples. The mean number concentration of peaks for dry cutting was composite dependent and varied over an order of magnitude with highest values for thicker laminates at the source being >1 × 106 particles cm-3. Concentration of respirable fibers for dry cutting at the source ranged from 2 to 4 fibers cm-3 depending on the composite type. Further investigation is required and underway to determine the effects of various exposure determinants, such as specimen and tool geometry, on particle release and effectiveness of controls.

  5. Fabrication of nanoscale to macroscale nickel-multiwall carbon nanotube hybrid materials with tunable material properties

    Science.gov (United States)

    Abdalla, Ahmed M.; Majdi, Tahereh; Ghosh, Suvojit; Puri, Ishwar K.

    2016-12-01

    To utilize their superior properties, multiwall carbon nanotubes (MWNTs) must be manipulated and aligned end-to-end. We describe a nondestructive method to magnetize MWNTs and provide a means to remotely manipulate them through the electroless deposition of magnetic nickel nanoparticles on their surfaces. The noncovalent bonds between Ni nanoparticles and MWNTs produce a Ni-MWNT hybrid material (NiCH) that is electrically conductive and has an enhanced magnetic susceptibility and elastic modulus. Our experiments show that MWNTs can be plated with Ni for Ni:MWNT weight ratios of γ = 1, 7, 14 and 30, to control the material properties. The phase, atom-level, and morphological information from x-ray diffraction, energy dispersive x-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, dark field STEM, and atomic force microscopy clarify the plating process and reveal the mechanical properties of the synthesized material. Ni metalizes at the surface of the Pd catalyst, forming a continuous wavy layer that encapsulates the MWNT surfaces. Subsequently, Ni acts as an autocatalyst, allowing the plating to continue even after the original Pd catalyst has been completely covered. Raising γ increases the coating layer thickness from 10 to 150 nm, which influences the NiCH magnetic properties and tunes its elastic modulus from 12.5 to 58.7 GPa. The NiCH was used to fabricate Ni-MWNT macrostructures and tune their morphologies by changing the direction of an applied magnetic field. Leveraging the hydrophilic Ni-MWNT outer surface, a water-based conductive ink was created and used to print a conductive path that had an electrical resistivity of 5.9 Ω m, illustrating the potential of this material for printing electronic circuits.

  6. Formation of coffee-stain patterns at the nanoscale: The role of nanoparticle solubility and solvent evaporation rate.

    Science.gov (United States)

    Zhang, Jianguo; Milzetti, Jasmin; Leroy, Frédéric; Müller-Plathe, Florian

    2017-03-21

    When droplets of nanoparticle suspension evaporate from surfaces, they leave behind a deposit of nanoparticles. The mechanism of evaporation-induced pattern formation in the deposit is studied by molecular dynamics simulations for sessile nanodroplets. The influence of the interaction between nanoparticles and liquid molecules and the influence of the evaporation rate on the final deposition pattern are addressed. When the nanoparticle-liquid interaction is weaker than the liquid-liquid interaction, an interaction-driven or evaporation-induced layer of nanoparticles appears at the liquid-vapor interface and eventually collapses onto the solid surface to form a uniform deposit independently of the evaporation rate. When the nanoparticle-liquid and liquid-liquid interactions are comparable, the nanoparticles are dispersed inside the droplet and evaporation takes place with the contact line pinned at a surface defect. In such a case, a pattern with an approximate ring-like shape is found with fast evaporation, while a more uniform distribution is observed with slower evaporation. When the liquid-nanoparticle interaction is stronger than the liquid-liquid interaction, evaporation always occurs with receding contact line. The final deposition pattern changes from volcano-like to pancake-like with decreasing evaporation rate. These findings might help to design nanoscale structures like nanopatterns or nanowires on surface through controlled solvent evaporation.

  7. Formation of coffee-stain patterns at the nanoscale: The role of nanoparticle solubility and solvent evaporation rate

    Science.gov (United States)

    Zhang, Jianguo; Milzetti, Jasmin; Leroy, Frédéric; Müller-Plathe, Florian

    2017-03-01

    When droplets of nanoparticle suspension evaporate from surfaces, they leave behind a deposit of nanoparticles. The mechanism of evaporation-induced pattern formation in the deposit is studied by molecular dynamics simulations for sessile nanodroplets. The influence of the interaction between nanoparticles and liquid molecules and the influence of the evaporation rate on the final deposition pattern are addressed. When the nanoparticle-liquid interaction is weaker than the liquid-liquid interaction, an interaction-driven or evaporation-induced layer of nanoparticles appears at the liquid-vapor interface and eventually collapses onto the solid surface to form a uniform deposit independently of the evaporation rate. When the nanoparticle-liquid and liquid-liquid interactions are comparable, the nanoparticles are dispersed inside the droplet and evaporation takes place with the contact line pinned at a surface defect. In such a case, a pattern with an approximate ring-like shape is found with fast evaporation, while a more uniform distribution is observed with slower evaporation. When the liquid-nanoparticle interaction is stronger than the liquid-liquid interaction, evaporation always occurs with receding contact line. The final deposition pattern changes from volcano-like to pancake-like with decreasing evaporation rate. These findings might help to design nanoscale structures like nanopatterns or nanowires on surface through controlled solvent evaporation.

  8. Development of 3d micro-nano hybrid patterns using anodized aluminum and micro-indentation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hong Gue; Kwon, Jong Tae [Division of Mechanical Engineering and Mechatronics, Kangwon National University, 1 Kangwondaehakgil, Chunchon, Gangwon-do, 200-701 (Korea, Republic of); Seo, Young Ho [Division of Mechanical Engineering and Mechatronics, Kangwon National University, 1 Kangwondaehakgil, Chunchon, Gangwon-do, 200-701 (Korea, Republic of)], E-mail: mems@kangwon.ac.kr; Kim, Byeong Hee [Division of Mechanical Engineering and Mechatronics, Kangwon National University, 1 Kangwondaehakgil, Chunchon, Gangwon-do, 200-701 (Korea, Republic of)

    2008-07-31

    We developed a simple and cost-effective method of fabricating 3D micro-nano hybrid patterns in which micro-indentation is applied on the anodized aluminum substrate. Nano-patterns were formed first on the aluminum substrate, and then micro-patterns were fabricated by deforming the nano-patterned aluminum substrate. Hemispherical nano-patterns with a 150 nm-diameter on an aluminum substrate were fabricated by anodizing and alumina removing process. Then, micro-pyramid patterns with a side-length of 50 {mu}m were formed on the nano-patterns using micro-indentation. To verify 3D micro-nano hybrid patterns, we replicated 3D micro-nano hybrid patterns by a hot-embossing process. 3D micro-nano hybrid patterns may be used in nano-photonic devices and nano-biochips applications.

  9. Nanoscale patterning of self-assembled monolayers using DNA nanostructure templates.

    Science.gov (United States)

    Surwade, S P; Zhou, F; Li, Z; Powell, A; O'Donnell, C; Liu, H

    2016-01-28

    We describe a method to pattern arbitrary-shaped silane self-assembled monolayers (SAMs) with nm scale resolution using DNA nanostructures as templates. The DNA nanostructures assembled on a silicon substrate act as a soft-mask to negatively pattern SAMs. Mixed SAMs can be prepared by back filling the negative tone patterns with a different silane.

  10. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications

    KAUST Repository

    Alias, Mohd Sharizal

    2015-12-22

    The high optical gain and absorption of organic–inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  11. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications.

    Science.gov (United States)

    Alias, Mohd S; Yang, Yang; Ng, Tien K; Dursun, Ibrahim; Shi, Dong; Saidaminov, Makhsud I; Priante, Davide; Bakr, Osman M; Ooi, Boon S

    2016-01-01

    The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  12. Strain-induced growth instability and nanoscale surface patterning in perovskite thin films

    Science.gov (United States)

    Pandya, Shishir; Damodaran, Anoop R.; Xu, Ruijuan; Hsu, Shang-Lin; Agar, Joshua C.; Martin, Lane W.

    2016-05-01

    Despite extensive studies on the effects of epitaxial strain on the evolution of the lattice and properties of materials, considerably less work has explored the impact of strain on growth dynamics. In this work, we demonstrate a growth-mode transition from 2D-step flow to self-organized, nanoscale 3D-island formation in PbZr0.2Ti0.8O3/SrRuO3/SrTiO3 (001) heterostructures as the kinetics of the growth process respond to the evolution of strain. With increasing heterostructure thickness and misfit dislocation formation at the buried interface, a periodic, modulated strain field is generated that alters the adatom binding energy and, in turn, leads to a kinetic instability that drives a transition from 2D growth to ordered, 3D-island formation. The results suggest that the periodically varying binding energy can lead to inhomogeneous adsorption kinetics causing preferential growth at certain sites. This, in conjunction with the presence of an Ehrlich-Schwoebel barrier, gives rise to long-range, periodically-ordered arrays of so-called “wedding cake” 3D nanostructures which self-assemble along the [100] and [010].

  13. Hybrid overlay metrology with CDSEM in a BEOL patterning scheme

    Science.gov (United States)

    Leray, Philippe; Jehoul, Christiane; Inoue, Osamu; Okagawa, Yutaka

    2015-03-01

    Overlay metrology accuracy is a major concern for our industry. Advanced logic process require more tighter overlay control for multipatterning schemes. TIS (Tool Induced Shift) and WIS (Wafer Induced Shift) are the main issues for IBO (Image Based Overlay) and DBO (Diffraction Based Overlay). Methods of compensation have been introduced, some are even very efficient to reduce these measured offsets. Another related question is about the overlay target designs. These targets are never fully representative of the design rules, strong efforts have been achieved, but the device cannot be completely duplicated. Ideally, we would like to measure in the device itself to verify the real overlay value. Top down CDSEM can measure critical dimensions of any structure, it is not dependent of specific target design. It can also measure the overlay errors but only in specific cases like LELE (Litho Etch Litho Etch) after final patterning. In this paper, we will revisit the capability of the CDSEM at final patterning by measuring overlay in dedicated targets as well as inside a logic and an SRAM design. In the dedicated overlay targets, we study the measurement differences between design rules gratings and relaxed pitch gratings. These relaxed pitch which are usually used in IBO or DBO targets. Beyond this "simple" LELE case, we will explore the capability of the CDSEM to measure overlay even if not at final patterning, at litho level. We will assess the hybridization of DBO and CDSEM for reference to optical tools after final patterning. We will show that these reference data can be used to validate the DBO overlay results (correctables and residual fingerprints).

  14. Nanoscale tomographic reconstruction of the subsurface mechanical properties of low-k high-aspect ratio patterns

    Science.gov (United States)

    Stan, Gheorghe; Mays, Ebony; Yoo, Hui Jae; King, Sean W.

    2016-12-01

    In this work, intermittent contact resonance atomic force microscopy (ICR-AFM) was performed on high-aspect ratio a-SiOC:H patterned fins (100 nm in height and width from 20 to 90 nm) to map the depth and width dependencies of the material stiffness. The spatial resolution and depth sensitivity of the measurements were assessed from tomographic cross-sections over various regions of interest within the 3D space of the measurements. Furthermore, the depth-dependence of the measured contact stiffness over the scanned area was used to determine the sub-surface variation of the elastic modulus at each point in the scan. This was achieved by iteratively adjusting the local elastic profile until the depth dependence of the resulted contact stiffness matched the depth dependence of the contact stiffness measured by ICR-AFM at that location. The results of this analysis were assembled into nanoscale sub-surface tomographic images of the elastic modulus of the investigated SiOC:H patterns. A new 3D structure-property representation emerged from these tomographic images with direct evidence for the alterations sustained by the structures during processing.

  15. Nanoscale patterning of a self-assembled monolayer by modification of the molecule–substrate bond

    Directory of Open Access Journals (Sweden)

    Cai Shen

    2014-03-01

    Full Text Available The intercalation of Cu at the interface of a self-assembled monolayer (SAM and a Au(111/mica substrate by underpotential deposition (UPD is studied as a means of high resolution patterning. A SAM of 2-(4'-methylbiphenyl-4-ylethanethiol (BP2 prepared in a structural phase that renders the Au substrate completely passive against Cu-UPD, is patterned by modification with the tip of a scanning tunneling microscope. The tip-induced defects act as nucleation sites for Cu-UPD. The lateral diffusion of the metal at the SAM–substrate interface and, thus, the pattern dimensions are controlled by the deposition time. Patterning down to the sub-20 nm range is demonstrated. The difference in strength between the S–Au and S–Cu bond is harnessed to develop the latent Cu-UPD image into a patterned binary SAM. Demonstrated by the exchange of BP2 by adamantanethiol (AdSH this is accomplished by a sequence of reductive desorption of BP2 in Cu free areas followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different.

  16. Nanoscale patterning of a self-assembled monolayer by modification of the molecule-substrate bond.

    Science.gov (United States)

    Shen, Cai; Buck, Manfred

    2014-01-01

    The intercalation of Cu at the interface of a self-assembled monolayer (SAM) and a Au(111)/mica substrate by underpotential deposition (UPD) is studied as a means of high resolution patterning. A SAM of 2-(4'-methylbiphenyl-4-yl)ethanethiol (BP2) prepared in a structural phase that renders the Au substrate completely passive against Cu-UPD, is patterned by modification with the tip of a scanning tunneling microscope. The tip-induced defects act as nucleation sites for Cu-UPD. The lateral diffusion of the metal at the SAM-substrate interface and, thus, the pattern dimensions are controlled by the deposition time. Patterning down to the sub-20 nm range is demonstrated. The difference in strength between the S-Au and S-Cu bond is harnessed to develop the latent Cu-UPD image into a patterned binary SAM. Demonstrated by the exchange of BP2 by adamantanethiol (AdSH) this is accomplished by a sequence of reductive desorption of BP2 in Cu free areas followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different.

  17. Nanoscale patterning of a self-assembled monolayer by modification of the molecule–substrate bond

    Science.gov (United States)

    Shen, Cai

    2014-01-01

    Summary The intercalation of Cu at the interface of a self-assembled monolayer (SAM) and a Au(111)/mica substrate by underpotential deposition (UPD) is studied as a means of high resolution patterning. A SAM of 2-(4'-methylbiphenyl-4-yl)ethanethiol (BP2) prepared in a structural phase that renders the Au substrate completely passive against Cu-UPD, is patterned by modification with the tip of a scanning tunneling microscope. The tip-induced defects act as nucleation sites for Cu-UPD. The lateral diffusion of the metal at the SAM–substrate interface and, thus, the pattern dimensions are controlled by the deposition time. Patterning down to the sub-20 nm range is demonstrated. The difference in strength between the S–Au and S–Cu bond is harnessed to develop the latent Cu-UPD image into a patterned binary SAM. Demonstrated by the exchange of BP2 by adamantanethiol (AdSH) this is accomplished by a sequence of reductive desorption of BP2 in Cu free areas followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different. PMID:24778947

  18. Nanoscale patterning, macroscopic reconstruction, and enhanced surface stress by organic adsorption on vicinal surfaces

    Science.gov (United States)

    Pollinger, Florian; Schmitt, Stefan; Sander, Dirk; Tian, Zhen; Kirschner, Jürgen; Vrdoljak, Pavo; Stadler, Christoph; Maier, Florian; Marchetto, Helder; Schmidt, Thomas; Schöll, Achim; Umbach, Eberhard

    2017-01-01

    Self-organization is a promising method within the framework of bottom-up architectures to generate nanostructures in an efficient way. The present work demonstrates that self-organization on the length scale of a few to several tens of nanometers can be achieved by a proper combination of a large (organic) molecule and a vicinal metal surface if the local bonding of the molecule on steps is significantly stronger than that on low-index surfaces. In this case thermal annealing may lead to large mass transport of the subjacent substrate atoms such that nanometer-wide and micrometer-long molecular stripes or other patterns are being formed on high-index planes. The formation of these patterns can be controlled by the initial surface orientation and adsorbate coverage. The patterns arrange self-organized in regular arrays by repulsive mechanical interactions over long distances accompanied by a significant enhancement of surface stress. We demonstrate this effect using the planar organic molecule PTCDA as adsorbate and Ag(10 8 7) and Ag(775) surfaces as substrate. The patterns are directly observed by STM, the formation of vicinal surfaces is monitored by high-resolution electron diffraction, the microscopic surface morphology changes are followed by spectro-microscopy, and the macroscopic changes of surface stress are measured by a cantilever bending method. The in situ combination of these complementary techniques provides compelling evidence for elastic interaction and a significant stress contribution to long-range order and nanopattern formation.

  19. Nanoscale patterns produced by self-sputtering of solid surfaces: The effect of ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, R. Mark [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Hofsäss, Hans [II. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

    2016-08-21

    A theory of the effect that ion implantation has on the patterns produced by ion bombardment of solid surfaces is introduced. For simplicity, the case of self-sputtering of an elemental material is studied. We find that implantation of self-ions has a destabilizing effect along the projected beam direction for angles of incidence θ that exceed a critical value. In the transverse direction, ion implantation has a stabilizing influence for all θ.

  20. Regular Nanoscale Protein Patterns via Directed Adsorption through Self-Assembled DNA Origami Masks.

    Science.gov (United States)

    Ramakrishnan, Saminathan; Subramaniam, Sivaraman; Stewart, A Francis; Grundmeier, Guido; Keller, Adrian

    2016-11-16

    DNA origami has become a widely used method for synthesizing well-defined nanostructures with promising applications in various areas of nanotechnology, biophysics, and medicine. Recently, the possibility to transfer the shape of single DNA origami nanostructures into different materials via molecular lithography approaches has received growing interest due to the great structural control provided by the DNA origami technique. Here, we use ordered monolayers of DNA origami nanostructures with internal cavities on mica surfaces as molecular lithography masks for the fabrication of regular protein patterns over large surface areas. Exposure of the masked sample surface to negatively charged proteins results in the directed adsorption of the proteins onto the exposed surface areas in the holes of the mask. By controlling the buffer and adsorption conditions, the protein coverage of the exposed areas can be varied from single proteins to densely packed monolayers. To demonstrate the versatility of this approach, regular nanopatterns of four different proteins are fabricated: the single-strand annealing proteins Redβ and Sak, the iron-storage protein ferritin, and the blood protein bovine serum albumin (BSA). We furthermore demonstrate the desorption of the DNA origami mask after directed protein adsorption, which may enable the fabrication of hierarchical patterns composed of different protein species. Because selectivity in adsorption is achieved by electrostatic interactions between the proteins and the exposed surface areas, this approach may enable also the large-scale patterning of other charged molecular species or even nanoparticles.

  1. Formation of patterned arrays of Au nanoparticles on SiC surface by template confined dewetting of normal and oblique deposited nanoscale films

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, F., E-mail: francesco.ruffino@ct.infn.it; Grimaldi, M.G.

    2013-06-01

    We report on the formation of patterned arrays of Au nanoparticles (NPs) on 6H SiC surface. To this end, we exploit the thermal-induced dewetting properties of a template confined deposited nanoscale Au film. In this approach, the Au surface pattern order, on the SiC substrate, is established by a template confined deposition using a micrometric template. Then, a dewetting process of the patterned Au film is induced by thermal processes. We compare the results, about the patterns formation, obtained for normal and oblique deposited Au films. We show that the normal and oblique depositions, through the same template, originate different patterns of the Au film. As a consequence of these different starting patterns, after the thermal processes, different patterns for the arrays of NPs originating from the dewetting mechanisms are obtained. For each fixed deposition angle α, the pattern evolution is analyzed, by scanning electron microscopy, as a function of the annealing time at 1173 K (900 °C). From these analyses, quantitative evaluations on the NPs size evolution are drawn. - Highlights: • Micrometric template-confined nanoscale gold films are deposited on silicon carbide. • The dewetting process of template-confined gold films on silicon carbide is studied. • Comparison of dewetting process of normal and oblique deposited gold films is drawn. • Patterned arrays of gold nanoparticles on silicon carbide surface are produced.

  2. Pulse-biased etching of Si3N4-layer in capacitively-coupled plasmas for nano-scale patterning of multi-level resist structures.

    Science.gov (United States)

    Lee, Hyelim; Kim, Sechan; Choi, Gyuhyun; Lee, Nae-Eung

    2014-12-01

    Pulse-biased plasma etching of various dielectric layers is investigated for patterning nano-scale, multi-level resist (MLR) structures composed of multiple layers via dual-frequency, capacitively-coupled plasmas (CCPs). We compare the effects of pulse and continuous-wave (CW) biasing on the etch characteristics of a Si3N4 layer in CF4/CH2F2/O2/Aretch chemistries using a dual-frequency, superimposed CCP system. Pulse-biasing conditions using a low-frequency power source of 2 MHz were varied by controlling duty ratio, period time, power, and the gas flow ratio in the plasmas generated by the 27.12 MHz high-frequency power source. Application of pulse-biased plasma etching significantly affected the surface chemistry of the etched Si3N4 surfaces, and thus modified the etching characteristics of the Si3N4 layer. Pulse-biased etching was successfully applied to patterning of the nano-scale line and space pattern of Si3N4 in the MLR structure of KrF photoresist/bottom anti-reflected coating/SiO2/amorphous carbon layer/Si3N4. Pulse-biased etching is useful for tuning the patterning of nano-scale dielectric hard-mask layers in MLR structures.

  3. Nanoscale growth and patterning of inorganic oxides using DNA nanostructure templates.

    Science.gov (United States)

    Surwade, Sumedh P; Zhou, Feng; Wei, Bryan; Sun, Wei; Powell, Anna; O'Donnell, Christina; Yin, Peng; Liu, Haitao

    2013-05-08

    We describe a method to form custom-shaped inorganic oxide nanostructures by using DNA nanostructure templates. We show that a DNA nanostructure can modulate the rate of chemical vapor deposition of SiO2 and TiO2 with nanometer-scale spatial resolution. The resulting oxide nanostructure inherits its shape from the DNA template. This method generates both positive-tone and negative-tone patterns on a wide range of substrates and is compatible with conventional silicon nanofabrication processes. Our result opens the door to the use of DNA nanostructures as general-purpose templates for high-resolution nanofabrication.

  4. Nanoscale pattern formation at surfaces under ion-beam sputtering: A perspective from continuum models

    Energy Technology Data Exchange (ETDEWEB)

    Cuerno, Rodolfo, E-mail: cuerno@math.uc3m.e [Departamento de Matematicas and Grupo Interdisciplinar de Sistemas Complejos (GISC), Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes, Madrid (Spain); Castro, Mario [GISC and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de Ingenieria (ICAI), Universidad Pontificia Comillas, E-28015 Madrid (Spain); Munoz-Garcia, Javier [Systems Biology Ireland and GISC, University College Dublin, Belfield, Dublin 4 (Ireland); Gago, Raul; Vazquez, Luis [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, E-28049 Madrid (Spain)

    2011-05-01

    Although reports on surface nanostructuring of solid targets by low to medium energy ion irradiation date back to the 1960s, only with the advent of high resolution tools for surface/interface characterization has the high potential of this procedure been recognized as a method for efficient production of surface patterns. Such morphologies are made up of periodic arrangements of nanometric sized features, like ripples and dots, with interest for technological applications due to their electronic, magnetic, and optical properties. Thus, roughly for the last ten years large efforts have been directed towards harnessing this nanofabrication technique. However, and particularly in view of recent experimental developments, we can say that the basic mechanisms controlling these pattern formation processes remain poorly understood. The lack of nanostructuring at low angles of incidence on some pure monoelemental targets, the role of impurities in the surface dynamics and other recent observations are challenging the classic view on the phenomenon as the mere interplay between the curvature dependence of the sputtering yield and surface diffusion. We review the main attempts at a theoretical (continuum) description of these systems, with emphasis on recent developments. Strong hints already exist that the nature of the morphological instability has to be rethought as originating in the material flow that is induced by the ion beam.

  5. PDMS-SiO{sub 2}-TiO{sub 2}-CaO hybrid materials – Cytocompatibility and nanoscale surface features

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, J. Carlos [CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Wacha, András [Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest 1117 (Hungary); Gomes, Pedro S.; Fernandes, M. Helena R. [Laboratory for Bone Metabolism and Regeneration, Faculdade de Medicina Dentária, Universidade do Porto (Portugal); Fernandes, M. Helena Vaz [CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Salvado, Isabel M. Miranda, E-mail: isabelmsalvado@ua.pt [CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal)

    2016-07-01

    Two PDMS-SiO{sub 2}-TiO{sub 2}-CaO porous hybrid materials were prepared using the same base composition, precursors, and solvents, but following two different sol-gel procedures, based on the authors' previous works where for the first time, in this hybrid system, calcium acetate was used as calcium source. The two different procedures resulted in monolithic materials with different structures, microstructures, and surface wettability. Even though both are highly hydrophobic (contact angles of 127.2° and 150.6°), and present different filling regimes due to different surface topographies, they have demonstrated to be cytocompatible when tested with human osteoblastic cells, against the accepted idea that high-hydrophobic surfaces are not suitable to cell adhesion and proliferation. At the nanoscale, the existence of hydrophilic silica domains containing calcium, where water molecules are physisorbed, is assumed to support this capability, as discussed. - Highlights: • Two hybrid materials were prepared following two different sol-gel procedures. • Both are highly hydrophobic but demonstrated to be cytocompatible. • Different filling regimes were observed.

  6. Frustration in a patterned array of nanoscale ferromagnetic islands: Artificial Spin Ice

    Science.gov (United States)

    Schiffer, Peter

    2008-03-01

    Geometrical frustration among spins in magnetic materials can lead to exotic low temperature states including ``spin ice'', in which the local moments mimic the frustration of hydrogen ion positions in frozen water. Our group has performed extensive studies of spin ice materials, and we have developed and studied an artificial geometrically frustrated magnet which shares many of the properties of the spin ice materials. This artificial frustrated system is an array of lithographically fabricated single-domain ferromagnetic islands. The islands are arranged such that the dipolar interactions between them are analogous to those in spin ice. Images of the magnetic moments of individual elements in this correlated system allow us to study the local accommodation of frustration. We see both ice-like short range correlations and an absence of long range correlations, behavior which is very similar to the low temperature state of spin ice. We have extended these studies to include theoretical analysis of the disordered state of moments. We have also used these arrays to analyze the process of demagnetization, which is necessary to access low energy collective states in our arrays and in many other magnetic systems. Our results shed light on the nature of frustration in patterned arrays and correspondingly demonstrate that artificial frustrated magnets can provide a rich new arena in which to study the physics of frustration. References: R. F. Wang et al. (Nature 2006 and Journal of Applied Physics 2007); C. Nisoli et al. (Physical Review Letters 2007).

  7. Effects of Bias Pulsing on Etching of SiO2 Pattern in Capacitively-Coupled Plasmas for Nano-Scale Patterning of Multi-Level Hard Masks.

    Science.gov (United States)

    Kim, Sechan; Choi, Gyuhyun; Chae, Heeyeop; Lee, Nae-Eung

    2016-05-01

    In order to study the effects of bias pulsing on the etching characteristics of a silicon dioxide (SiO2) layer using multi-level hard mask (MLHM) structures of ArF photoresist/bottom anti-reflected coating/SiO2/amorphous carbon layer (ACL)/SiO2, the effects of bias pulsing conditions on the etch characteristics of a SiO2 layer with an ACL mask pattern in C4F8/CH2F2/O2/Ar etch chemistries were investigated in a dual-frequency capacitively-coupled plasma (CCP) etcher. The effects of the pulse frequency, duty ratio, and pulse-bias power in the 2 MHz low-frequency (LF) power source were investigated in plasmas generated by a 27.12 MHz high-frequency (HF) power source. The etch rates of ACL and SiO2 decreased, but the etch selectivity of SiO2/ACL increased with decreasing duty ratio. When the ACL and SiO2 layers were etched with increasing pulse frequency, no significant change was observed in the etch rates and etch selectivity. With increasing LF pulse-bias power, the etch rate of ACL and SiO2 slightly increased, but the etch selectivity of SiO2/ACL decreased. Also, the precise control of the critical dimension (CD) values with decreasing duty ratio can be explained by the protection of sidewall etching of SiO2 by increased passivation. Pulse-biased etching was successfully applied to the patterning of the nano-scale line and space of SiO2 using an ACL pattern.

  8. Hybridization of mouse lemurs: different patterns under different ecological conditions

    Directory of Open Access Journals (Sweden)

    Rosenkranz David

    2011-10-01

    Full Text Available Abstract Background Several mechanistic models aim to explain the diversification of the multitude of endemic species on Madagascar. The island's biogeographic history probably offered numerous opportunities for secondary contact and subsequent hybridization. Existing diversification models do not consider a possible role of these processes. One key question for a better understanding of their potential importance is how they are influenced by different environmental settings. Here, we characterized a contact zone between two species of mouse lemurs, Microcebus griseorufus and M. murinus, in dry spiny bush and mesic gallery forest that border each other sharply without intermediate habitats between them. We performed population genetic analyses based on mtDNA sequences and nine nuclear microsatellites and compared the results to a known hybrid zone of the same species in a nearby wide gradient from dry spiny bush over transitional forest to humid littoral forest. Results In the spiny-gallery system, Microcebus griseorufus is restricted to the spiny bush; Microcebus murinus occurs in gallery forest and locally invades the dryer habitat of its congener. We found evidence for bidirectional introgressive hybridization, which is closely linked to increased spatial overlap within the spiny bush. Within 159 individuals, we observed 18 hybrids with mitochondrial haplotypes of both species. Analyses of simulated microsatellite data indicate that we identified hybrids with great accuracy and that we probably underestimated their true number. We discuss short-term climatic fluctuations as potential trigger for the dynamic of invasion and subsequent hybridization. In the gradient hybrid zone in turn, long-term aridification could have favored unidirectional nuclear introgression from Microcebus griseorufus into M. murinus in transitional forest. Conclusions Madagascar's southeastern transitional zone harbors two very different hybrid zones of mouse lemurs

  9. Alumina-clay nanoscale hybrid filler assembling in cross-linked polyethylene based nanocomposites: mechanics and thermal properties.

    Science.gov (United States)

    Jose, Josmin P; Thomas, Sabu

    2014-07-28

    Herein, investigation on XLPE-Al2O3-clay ternary hybrid systems of Al2O3 and clay in 1 : 1 and 2 : 1 ratios, binary systems of XLPE-clay and XLPE-Al2O3 nanocomposites, with special reference to the hybrid filler effect and the superior microstructural development in ternary systems is conducted. The ternary hybrid composite of Al2O3 and clay in a 1 : 1 ratio exhibits the highest tensile strength (100% increase) and Young's modulus (208% increase), followed by the Al2O3 : clay = 2 : 1 system. The interaction between alumina and clay altered the composite morphology, filler dispersion and gave rise to a unique filler architecture leading to a substantial boost up in mechanics compared to predictions based on the idealized filler morphology. Experimentally observed much higher mechanics compared to theoretical predictions confirmed that the dramatic improvement in mechanics is the outcome of the positive hybrid effect and a second factor of synergism, i.e. filler-filler networks. Morphological control of the hybrid filler network is realized by adjusting the ratio between different fillers. For the Al2O3 : clay = 2 : 1 system, the microstructural limitation of dispersion due to the steric effect of alumina clusters shifts the properties to the negative hybrid effect region.

  10. Mapping the Photoresponse of CH3NH3PbI3 Hybrid Perovskite Thin Films at the Nanoscale.

    Science.gov (United States)

    Kutes, Yasemin; Zhou, Yuanyuan; Bosse, James L; Steffes, James; Padture, Nitin P; Huey, Bryan D

    2016-06-08

    Perovskite solar cells (PSCs) based on thin films of organolead trihalide perovskites (OTPs) hold unprecedented promise for low-cost, high-efficiency photovoltaics (PVs) of the future. While PV performance parameters of PSCs, such as short circuit current, open circuit voltage, and maximum power, are always measured at the macroscopic scale, it is necessary to probe such photoresponses at the nanoscale to gain key insights into the fundamental PV mechanisms and their localized dependence on the OTP thin-film microstructure. Here we use photoconductive atomic force microscopy spectroscopy to map for the first time variations of PV performance at the nanoscale for planar PSCs based on hole-transport-layer free methylammonium lead triiodide (CH3NH3PbI3 or MAPbI3) thin films. These results reveal substantial variations in the photoresponse that correlate with thin-film microstructural features such as intragrain planar defects, grains, grain boundaries, and notably also grain-aggregates. The insights gained into such microstructure-localized PV mechanisms are essential for guiding microstructural tailoring of OTP films for improved PV performance in future PSCs.

  11. Properties and Application Perspective of Hybrid Titania-Silica Patterns Fabricated by Inkjet Printing.

    Science.gov (United States)

    Dzik, Petr; Veselý, Michal; Kete, Marko; Pavlica, Egon; Štangar, Urška Lavrenčič; Neumann-Spallart, Michael

    2015-08-01

    A hybrid titania-silica cold-setting sol has been developed that can be deposited onto a wide variety of surfaces without the need for high-temperature fixing and that is suitable for material printing deposition. Thin hybrid titania-silica coatings were patterned onto glass and PET substrates by inkjet printing. Well-defined hybrid titania-silica patterns, with thicknesses ranging from 40 to 400 nm, were fabricated by overprinting 1 to 10 layers. Excellent mechanical, optical, and photocatalytic properties were observed, making the reported material well suited for the fabrication of transparent self-cleaning coatings both on mineral and organic substrates. The printed patterns exhibit photoelectrochemical activity that can be further improved by thermal or photonic curing. A concept of fully printed interdigitated photoelectrochemical cells on flexible PET substrates utilizing the reported hybrid photocatalyst is disclosed as well.

  12. Hybrid functionals with fixed mixing parameter perform no better than PBE for fundamental band gaps of nanoscale materials

    Science.gov (United States)

    Wang, Xinquan; Dvorac, Marc; Wu, Zhigang

    2016-11-01

    Hybrid functionals mixing the exact exchange with (semi)local functionals to reinstall the missing derivative discontinuity have been successfully employed to predict band gaps (Eg) in bulk semiconductors. Here we show that traditional hybrid functionals with fixed fractions of exact exchange do not perform significantly better than the most popular semilocal PBE-GGA functional for Eg of semiconductor nanostructures, since their band-gap corrections are essentially size independent. This is because they cannot respond properly to the variation in screening when size changes. They merely predict constant band-gap corrections to the PBE gaps in silicon nanowires (Si NWs) when wire diameter reduces, instead of the dramatic increase predicted by many-body G W calculations. Moreover, these hybrid functionals generate almost identical wave functions compared with PBE for both bulk Si and Si NWs, whose overlaps with corresponding quasiparticle wave functions become much smaller than 1 for narrow NWs.

  13. Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature

    Science.gov (United States)

    This review focus on environmental implications and applications of engineered magnetite (Fe3O4) nanoparticles (MNPs) as a single phase or a component of a hybrid nanocomposite that take advantages of their superparamagnetism and high surface area. MNPs are synthesized via co-pre...

  14. Inconsistent phylogeographic pattern between a sperm dependent fish and its host: in situ hybridization vs dispersal.

    Science.gov (United States)

    Vergilino, Roland; Leung, Christelle; Angers, Bernard

    2016-09-06

    Co-dispersal of sperm-dependent hybrids and their sexual relatives is expected to result in consistent spatial patterns between assemblages of hybrids and genetic structure of parental species. However, local hybridization events may blur this signal as assemblages could be organized under different connectivity constraints. This study aims at testing the hypothesis of local hybridization events by comparing the assemblage of hybrid fish Chrosomus eos-neogaeus to the genetic diversity of one of its parental species, Chrosomus eos. An extensive survey performed on a total of 132 sites located in two regions of Southern Quebec (West-Qc and East-Qc) revealed a distinct organization of hybrid lineages. One of the six hybrid lineages detected in West-Qc is widespread throughout this region resulting in a low α-diversity (1.38) and β-diversity (4.35). On the other hand, 36 hybrid lineages were detected in East-Qc and displayed narrow geographic distributions leading to a high α-diversity (2.30) and β-diversity (15.68). In addition, the C. eos multilocus haplotype of several of these hybrids is assigned to their respective sympatric C. eos population. Finally, contrasting with hybrids, the paternal species C. eos displayed a higher ρST in West-Qc (0.2300) than in East-Qc (0.0734). The unusually high diversity of hybrid lineages in East-Qc as well as the spatial organization and the close genetic relationship with C. eos sympatric populations support the hypothesis that multiple hybridization events occurred in situ. These findings coupled to the near absence of the maternal species Chrosomus neogeaus suggest that the decline of this species could be the trigger event at the origin of the high rates of spontaneous hybridization in this region.

  15. Characterization of exposures to nanoscale particles and fibers during solid core drilling of hybrid carbon nanotube advanced composites.

    Science.gov (United States)

    Bello, Dhimiter; Wardle, Brian L; Zhang, Jie; Yamamoto, Namiko; Santeufemio, Christopher; Hallock, Marilyn; Virji, M Abbas

    2010-01-01

    This work investigated exposures to nanoparticles and nanofibers during solid core drilling of two types of advanced carbon nanotube (CNT)-hybrid composites: (1) reinforced plastic hybrid laminates (alumina fibers and CNT); and (2) graphite-epoxy composites (carbon fibers and CNT). Multiple real-time instruments were used to characterize the size distribution (5.6 nm to 20 microm), number and mass concentration, particle-bound polyaromatic hydrocarbons (b-PAHs), and surface area of airborne particles at the source and breathing zone. Time-integrated samples included grids for electron microscopy characterization of particle morphology and size resolved (2 nm to 20 microm) samples for the quantification of metals. Several new important findings herein include generation of airborne clusters of CNTs not seen during saw-cutting of similar composites, fewer nanofibers and respirable fibers released, similarly high exposures to nanoparticles with less dependence on the composite thickness, and ultrafine (composite material.

  16. Patterned hybrid nanohole array surfaces for cell adhesion and migration.

    Science.gov (United States)

    Westcott, Nathan P; Lou, Yi; Muth, John F; Yousaf, Muhammad N

    2009-10-06

    We report the fabrication of hybrid nanohole array surfaces to study the role of the surface nanoevironment on cell adhesion and cell migration. We use polystyrene beads and reactive ion etching to control the size and the spacing between nanoholes on a tailored self-assembled monolayer inert gold surface. The arrays were characterized by scanning electron microscopy and brightfield microscopy. For cell adhesion studies, cells were seeded to these substrates to study the effect of ligand spacing on cell spreading, stress fiber formation, and focal adhesion structure and size. Finally, comparative cell migration rates were examined on the various nanohole array surfaces using time-lapse microscopy.

  17. Nanoscale charge localization induced by random orientations of organic molecules in hybrid perovskite CH3NH3PbI3

    Science.gov (United States)

    Ma, Jie; Wang, Lin-Wang

    2015-03-01

    Perovskite-based solar cells have achieved high solar-energy conversion efficiencies and attracted wide attentions nowadays. Despite the rapid progress in solar-cell devices, many fundamental issues of the hybrid perovskites have not been fully understood. Experimentally, it is well known that in CH3NH3PbI3, the organic molecules CH3NH3 are randomly orientated at the room temperature, but the impact of the random molecular orientation has not been investigated. Using linear-scaling ab-initiomethods, we have calculated the electronic structures of the tetragonal phase of CH3NH3PbI3 with randomly orientated organic molecules in large supercells up to ~20,000 atoms. Due to the dipole moment of the organic molecule, the random orientation creates a novel system with long-range potential fluctuations unlike alloys or other conventional disordered systems. We find that the charge densities of the conduction-band minimum and the valence-band maximum are localized separately in nanoscales due to the potential fluctuations. The charge localization causes electron-hole separation and reduces carrier recombination rates, which may contribute to the long carrier lifetime observed in experiments. We have also proposed a model to explain the charge localization.

  18. Using NV centers to probe magnetization dynamics in normal metal/magnetic insulator hybrid system at the nanoscale

    Science.gov (United States)

    Zhang, Huiliang; Ku, Mark J. H.; Han, Minyong; Casola, Francesco; van der Sar, Toeno; Yacoby, Amir; Walsworth, Ronald L.

    2016-05-01

    Understanding magnetization dynamics induced by electric current is of great interest for both fundamental and practical reasons. Great endeavor has been dedicated to spin-orbit torques (SOT) in metallic structures, while quantitative study of analogous phenomena in magnetic insulators remains challenging where transport measurements are not feasible. Recently we have developed techniques using nitrogen vacancy (NV) centers in diamond to probe few-nanometre-scale correlated-electron magnetic excitations (i.e., spin waves). Here we demonstrate how this powerful tool can be implemented to study magnetization dynamics inside ferromagnetic insulator, Yttrium iron garnet (YIG) with spin injection from electrical current through normal metal (Platinum in our case). Particularly our work will focus on NV magnetic detection, imaging, and spectroscopy of coherent auto-oscillations in Pt/YIG microdisc. Magnetic fluctuations and local temperature measurements, both with nearby NV centers, will also be interesting topics relevant to SOT physics in Pt/YIG hybrid system.

  19. Thermal conductivity prediction of nanoscale phononic crystal slabs using a hybrid lattice dynamics-continuum mechanics technique

    Directory of Open Access Journals (Sweden)

    Charles M. Reinke

    2011-12-01

    Full Text Available Recent work has demonstrated that nanostructuring of a semiconductor material to form a phononic crystal (PnC can significantly reduce its thermal conductivity. In this paper, we present a classical method that combines atomic-level information with the application of Bloch theory at the continuum level for the prediction of the thermal conductivity of finite-thickness PnCs with unit cells sized in the micron scale. Lattice dynamics calculations are done at the bulk material level, and the plane-wave expansion method is implemented at the macrosale PnC unit cell level. The combination of the lattice dynamics-based and continuum mechanics-based dispersion information is then used in the Callaway-Holland model to calculate the thermal transport properties of the PnC. We demonstrate that this hybrid approach provides both accurate and efficient predictions of the thermal conductivity.

  20. Thermal conductivity prediction of nanoscale phononic crystal slabs using a hybrid lattice dynamics-continuum mechanics technique

    Science.gov (United States)

    Reinke, Charles M.; Su, Mehmet F.; Davis, Bruce L.; Kim, Bongsang; Hussein, Mahmoud I.; Leseman, Zayd C.; Olsson-III, Roy H.; El-Kady, Ihab

    2011-12-01

    Recent work has demonstrated that nanostructuring of a semiconductor material to form a phononic crystal (PnC) can significantly reduce its thermal conductivity. In this paper, we present a classical method that combines atomic-level information with the application of Bloch theory at the continuum level for the prediction of the thermal conductivity of finite-thickness PnCs with unit cells sized in the micron scale. Lattice dynamics calculations are done at the bulk material level, and the plane-wave expansion method is implemented at the macrosale PnC unit cell level. The combination of the lattice dynamics-based and continuum mechanics-based dispersion information is then used in the Callaway-Holland model to calculate the thermal transport properties of the PnC. We demonstrate that this hybrid approach provides both accurate and efficient predictions of the thermal conductivity.

  1. Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chunming, E-mail: su.chunming@epa.gov

    2017-01-15

    Highlights: • Environmental impact of engineered MNPs. • MNPs and their hybrids explored for use in energy, analytical chemistry, and catalysis. • Surface modification to MNPs allow biocompatible applications. • Adsorptive and separative removal of a wide range of contaminants from aquatic environments. • Active remediation and natural attenuation of contaminants in soil and groundwater using MNPs. - Abstract: This review focuses on environmental implications and applications of engineered magnetite (Fe{sub 3}O{sub 4}) nanoparticles (MNPs) as a single phase or a component of a hybrid nanocomposite that exhibits superparamagnetism and high surface area. MNPs are synthesized via co-precipitation, thermal decomposition and combustion, hydrothermal process, emulsion, microbial process, and green approaches. Aggregation/sedimentation and transport of MNPs depend on surface charge of MNPs and geochemical parameters such as pH, ionic strength, and organic matter. MNPs generally have low toxicity to humans and ecosystem. MNPs are used for constructing chemical/biosensors and for catalyzing a variety of chemical reactions. MNPs are used for air cleanup and carbon sequestration. MNP nanocomposites are designed as antimicrobial agents for water disinfection and flocculants for water treatment. Conjugated MNPs are widely used for adsorptive/separative removal of organics, dyes, oil, arsenic, phosphate, molybdate, fluoride, selenium, Cr(VI), heavy metal cations, radionuclides, and rare earth elements. MNPs can degrade organic/inorganic contaminants via chemical reduction or catalyze chemical oxidation in water, sediment, and soil. Future studies should further explore mechanisms of MNP interactions with other nanomaterials and contaminants, economic and green approaches of MNP synthesis, and field scale demonstration of MNP utilization.

  2. Hybrid model for forecasting time series with trend, seasonal and salendar variation patterns

    Science.gov (United States)

    Suhartono; Rahayu, S. P.; Prastyo, D. D.; Wijayanti, D. G. P.; Juliyanto

    2017-09-01

    Most of the monthly time series data in economics and business in Indonesia and other Moslem countries not only contain trend and seasonal, but also affected by two types of calendar variation effects, i.e. the effect of the number of working days or trading and holiday effects. The purpose of this research is to develop a hybrid model or a combination of several forecasting models to predict time series that contain trend, seasonal and calendar variation patterns. This hybrid model is a combination of classical models (namely time series regression and ARIMA model) and/or modern methods (artificial intelligence method, i.e. Artificial Neural Networks). A simulation study was used to show that the proposed procedure for building the hybrid model could work well for forecasting time series with trend, seasonal and calendar variation patterns. Furthermore, the proposed hybrid model is applied for forecasting real data, i.e. monthly data about inflow and outflow of currency at Bank Indonesia. The results show that the hybrid model tend to provide more accurate forecasts than individual forecasting models. Moreover, this result is also in line with the third results of the M3 competition, i.e. the hybrid model on average provides a more accurate forecast than the individual model.

  3. Dynamics of asymmetrical hybridization in North American wood ferns: reconciling patterns of inheritance with gametophyte reproductive biology.

    Science.gov (United States)

    Testo, Weston L; Watkins, James E; Barrington, David S

    2015-04-01

    Hybridization is an important evolutionary force in plants, but the mechanisms underlying it have not been well studied for many groups. In particular, the drivers of non-random patterns of interspecific gene flow (asymmetrical hybridization) remain poorly understood, especially in the seed-free vascular plants. Here, we examine patterns of asymmetrical hybridization in two widespread fern hybrids from eastern North America and study the role of gametophyte ecology in the determination of hybridization bias. We characterized the maternal parentage of > 140 hybrid sporophytes by sequencing a c. 350-bp region of chloroplast DNA (cpDNA). To identify factors contributing to patterns of asymmetrical hybridization, we cultured gametophytes of the parental species and evaluated critical aspects of their reproductive biology. We found that asymmetrical hybridization was prevalent across the populations of both hybrids. Reproductive traits varied across species and suggest that selfing potential, antheridiogen responsiveness, sperm dispersal capacity and gamete size all contribute to the mediation of the direction of hybridization in this group. Our findings suggest that asymmetrical hybridization in ferns is driven by an array of reproductive traits. This study helps to sharpen and define a mechanistic understanding of patterns of hybridization in this group and demonstrates the importance of considering gametophyte biology when studying evolutionary processes in ferns.

  4. Assessing rates and patterns of hybridization between wild boar and domestic pig in Europe

    DEFF Research Database (Denmark)

    Canu, Antonio; Iacolina, Laura; Apollonio, Marco

    . However, despite the availability of multiple molecular markers, with different inheritance systems and undergoing different selective pressures, the analysis on the extent and impact of introgressive hybridization in Europe remains challenging. Here we show the outcome of the application of different......Introgressive hybridization between wild boar and domestic pig has unpredictable evolutionary consequences and has the potential to alter reproductive, immunological and behavioural traits, influencing individual fitness and possibly increasing species' invasiveness. Though of great interest......, reconstructing patterns of gene flow between wild and domestic form of Sus scrofa is arduous. In fact, hybridization patterns may differ greatly with respect to time (ancient vs. recent), source (intentional in captivity vs. unintentional in the wild), spread (extensive vs. occasional) and directionality (i...

  5. The pachytene checkpoint and its relationship to evolutionary patterns of polyploidization and hybrid sterility.

    Science.gov (United States)

    Li, X C; Barringer, B C; Barbash, D A

    2009-01-01

    Sterility is a commonly observed phenotype in interspecific hybrids. Sterility may result from chromosomal or genic incompatibilities, and much progress has been made toward understanding the genetic basis of hybrid sterility in various taxa. The underlying mechanisms causing hybrid sterility, however, are less well known. The pachytene checkpoint is a meiotic surveillance system that many organisms use to detect aberrant meiotic products, in order to prevent the production of defective gametes. We suggest that activation of the pachytene checkpoint may be an important mechanism contributing to two types of hybrid sterility. First, the pachytene checkpoint may form the mechanistic basis of some gene-based hybrid sterility phenotypes. Second, the pachytene checkpoint may be an important mechanism that mediates chromosomal-based hybrid sterility phenotypes involving gametes with non-haploid (either non-reduced or aneuploid) chromosome sets. Studies in several species suggest that the strength of the pachytene checkpoint is sexually dimorphic, observations that warrant future investigation into whether such variation may contribute to differences in patterns of sterility between male and female interspecific hybrids. In addition, plants seem to lack the pachytene checkpoint, which correlates with increased production of unreduced gametes and a higher incidence of polyploid species in plants versus animals. Although the pachytene checkpoint occurs in many animals and in fungi, at least some of the genes that execute the pachytene checkpoint are different among organisms. This finding suggests that the penetrance of the pachytene checkpoint, and even its presence or absence can evolve rapidly. The surprising degree of evolutionary flexibility in this meiotic surveillance system may contribute to the observed variation in patterns of hybrid sterility and in rates of polyploidization.

  6. Micrometer and nanometer-scale parallel patterning of ceramic and organic-inorganic hybrid materials

    NARCIS (Netherlands)

    ten Elshof, Johan E.; Khan, Sajid; Göbel, Ole

    2010-01-01

    This review gives an overview of the progress made in recent years in the development of low-cost parallel patterning techniques for ceramic materials, silica, and organic–inorganic silsesquioxane-based hybrids from wet-chemical solutions and suspensions on the micrometer and nanometer-scale. The

  7. Pool-Boiling Heat-Transfer Enhancement on Cylindrical Surfaces with Hybrid Wettable Patterns.

    Science.gov (United States)

    Kumar C S, Sujith; Chang, Yao Wen; Chen, Ping-Hei

    2017-04-10

    In this study, pool-boiling heat-transfer experiments were performed to investigate the effect of the number of interlines and the orientation of the hybrid wettable pattern. Hybrid wettable patterns were produced by coating superhydrophilic SiO2 on a masked, hydrophobic, cylindrical copper surface. Using de-ionized (DI) water as the working fluid, pool-boiling heat-transfer studies were conducted on the different surface-treated copper cylinders of a 25-mm diameter and a 40-mm length. The experimental results showed that the number of interlines and the orientation of the hybrid wettable pattern influenced the wall superheat and the HTC. By increasing the number of interlines, the HTC was enhanced when compared to the plain surface. Images obtained from the charge-coupled device (CCD) camera indicated that more bubbles formed on the interlines as compared to other parts. The hybrid wettable pattern with the lowermost section being hydrophobic gave the best heat-transfer coefficient (HTC). The experimental results indicated that the bubble dynamics of the surface is an important factor that determines the nucleate boiling.

  8. Response of SC704 maize hybrid seed production to planting pattern

    African Journals Online (AJOL)

    Mohammed Reza

    2012-05-08

    May 8, 2012 ... 1Safiabad Research Center, Dezful, Iran. 2Department of ... Key words: Planting pattern, seed produce, corn grain, S.C.704 hybrid. INTRODUCTION ... plants for light, moisture and food would decrease and plants will have a ...

  9. Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout

    Science.gov (United States)

    Muhlfeld, Clint C.; Kovach, Ryan P.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David A.; Shepard, Bradley B.; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W.

    2017-01-01

    Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large, multi-decade genetics dataset (N = 582 sites, 12,878 individuals) with high-resolution climate predictions and extensive stocking records, we evaluate the spatiotemporal dynamics of hybridization between native cutthroat trout and invasive rainbow trout, the world’s most widely introduced invasive fish, across the northern Rocky Mountains of the United States. Historical effects of stocking and contemporary patterns of climatic variation were strongly related to the spread of hybridization across space and time. The probability of occurrence, extent of, and temporal changes in hybridization increased at sites in close proximity to historical stocking locations with greater rainbow trout propagule pressure, warmer water temperatures, and lower spring precipitation. Although locations with warmer water temperatures were more prone to hybridization, cold sites were not protected from invasion; 58% of hybridized sites had cold mean summer water temperatures (<11oC). Despite cessation of stocking over 40 years ago, hybridization increased over time at half (50%) of the locations with long-term data, the vast majority of which (74%) were initially non-hybridized, emphasizing the chronic, negative impacts of human-mediated hybridization. These results show that effects of climate change on biodiversity must be analyzed in the context of historical human impacts that set ecological and evolutionary trajectories.

  10. Patterns of Cytosine Methylation in Parental Lines and Their Hybrids of Large White and Meishan Reciprocal Crosses

    Institute of Scientific and Technical Information of China (English)

    JIANG Cao-de; DENG Chang-yan; XIONG Yuan-zhu

    2004-01-01

    The extent and patterns of cytosine methylation in blood DNA were assessed, using the technique of methylation-sensitive amplified polymorphism(MSAP),in Meishan, Large White pigs and hybrids of their reciprocal crosses. In all, 1 508 fragments, each representing a recognition site cleaved by either or both of the isoschizomers, MspI and HpaII, were amplified using 20 pairs of selective primers. 10.3% of CCGG sites were methylated in Meishan pigs, 10.5% in Large White pigs, and 10.2% in the hybrids. Cytosine methylation was not significantly different among parental lines and hybrids of reciprocal crosses. Four classes of patterns were identified in a comparative assay of cytosine methylation in the parents and hybrids: (1) the same level of methylation in both parental lines and the hybrids; (2) the same level of methylation in either parent or hybrid; (3) an increased level of methylation in the hybrids compared to the parents, and (4) a decreased level of methylation in the hybrids. 11 crossspecific methylation sites were detected in F1 hybrids of Large White×Meishan, and 10 crossspecific methylation sites in the hybrid of Meishan×LargeWhite. In conclusion, (1) the whole methylation status between parental lines and hybrids was not different, but specific sites were differentially methylated; (2) specific sites were differentially methylated between reciprocal crosses; (3) demethylation and hypermethylation of many sites accounted for mostly (more than 50%) methylated sites in the hybrids compared to parental lines.

  11. Chemical tailoring of hybrid sol-gel thick coatings as hosting matrix for functional patterned microstructures.

    Science.gov (United States)

    Falcaro, Paolo; Costacurta, Stefano; Malfatti, Luca; Buso, Dario; Patelli, Alessandro; Schiavuta, Piero; Piccinini, Massimo; Grenci, Gianluca; Marmiroli, Benedetta; Amenitsch, Heinz; Innocenzi, Plinio

    2011-02-01

    A phenyl-based hybrid organic - inorganic coating has been synthesized and processed by hard X-ray lithography. The overall lithography process is performed in a two-step process only (X-rays exposure and chemical etching). The patterns present high aspect ratio, sharp edges, and high homogeneity. The coating has been doped with a variety of polycyclic aromatic hydrocarbon functional molecules, such as anthracene, pentacene, and fullerene. For the first time, hard X-rays have been combined with thick hybrid functional coatings, using the sol-gel thick film directly as resist. A new technique based on a new material combined with hard X-rays is now available to fabricate optical devices. The effect due to the high-energy photon exposure has been investigated using FT-IR and Raman spectroscopy, laser scanner, optical profilometer, and confocal and electron microscope. High-quality thick hybrid fullerene-doped microstructures have been fabricated.

  12. Hybrid approach for Image Encryption Using SCAN Patterns and Carrier Images

    CERN Document Server

    T, Panduranga H

    2010-01-01

    We propose a hybrid technique for image encryption which employs the concept of carrier image and SCAN patterns generated by SCAN methodology. Although it involves existing method like SCAN methodology, the novelty of the work lies in hybridizing and carrier image creation for encryption. Here the carrier image is created with the help of alphanumeric keyword. Each alphanumeric key will be having a unique 8bit value generated by 4 out of 8-code. This newly generated carrier image is added with original image to obtain encrypted image. The scan methodology is applied to either original image or carrier image, after the addition of original image and carrier image to obtain highly distorted encrypted image. The resulting image is found to be more distorted in hybrid technique. By applying the reverse process we get the decrypted image.

  13. Genetic Segregation and Genomic Hybridization Patterns Support an Allotetraploid Structure and Disomic Inheritance for Salix Species

    Directory of Open Access Journals (Sweden)

    Gianni Barcaccia

    2014-09-01

    Full Text Available The Salix alba L. (white willow—Salix fragilis L. (crack willow complex includes closely related polyploid species, mainly tetraploid (2n = 4x = 76, which are dioecious and hence obligate allogamous. Because little is known about the genome constitution and chromosome behavior of these pure willow trees, genetic analysis of their naturally occurring interspecific polyploid hybrids is still very difficult. A two-way pseudo-testcross strategy was exploited using single-dose AFLP markers in order to assess the main inheritance patterns of tetraploid biotypes (disomy vs. tetrasomy in segregating populations stemmed from S. alba × S. fragilis crosses and reciprocals. In addition, a genomic in situ hybridization (GISH technology was implemented in willow to shed some light on the genome structure of S. alba and S. fragilis species, and their hybrids (allopolyploidy vs. autopolyploidy. The frequency of S. alba-specific molecular markers was almost double compared to that of S. fragilis-specific ones, suggesting the phylogenetic hypothesis of S. fragilis as derivative species from S. alba-like progenitors. Cytogenetic observations at pro-metaphase revealed about half of the chromosome complements being less contracted than the remaining ones, supporting an allopolyploid origin of both S. alba and S. fragilis. Both genetic segregation and genomic hybridization data are consistent with an allotetraploid nature of the Salix species. In particular, the vast majority of the AFLP markers were inherited according to disomic patterns in S. alba × S. fragilis populations and reciprocals. Moreover, in all S. alba against S. fragilis hybridizations and reciprocals, GISH signals were observed only on the contracted chromosomes whereas the non-contracted chromosomes were never hybridized. In conclusion, half of the chromosomes of the pure species S. alba and S. fragilis are closely related and they could share a common diploid ancestor, while the rest of

  14. DNA Polymer Brush Patterning through Photocontrollable Surface-Initiated DNA Hybridization Chain Reaction.

    Science.gov (United States)

    Huang, Fujian; Zhou, Xiang; Yao, Dongbao; Xiao, Shiyan; Liang, Haojun

    2015-11-18

    The fabrication of DNA polymer brushes with spatial resolution onto a solid surface is a crucial step for biochip research and related applications, cell-free gene expression study, and even artificial cell fabrication. Here, for the first time, a DNA polymer brush patterning method is reported based on the photoactivation of an ortho-nitrobenzyl linker-embedded DNA hairpin structure and a subsequent surface-initiated DNA hybridization chain reaction (HCR). Inert DNA hairpins are exposed to ultraviolet light irradiation to generate DNA duplexes with two active sticky ends (toeholds) in a programmable manner. These activated DNA duplexes can initiate DNA HCR to generate multifunctional patterned DNA polymer brushes with complex geometrical shapes. Different multifunctional DNA polymer brush patterns can be fabricated on certain areas of the same solid surface using this method. Moreover, the patterned DNA brush surface can be used to capture target molecules in a desired manner.

  15. Three-year randomised clinical trial to evaluate the clinical performance, quantitative and qualitative wear patterns of hybrid composite restorations.

    Science.gov (United States)

    Palaniappan, Senthamaraiselvi; Elsen, Liesbeth; Lijnen, Inge; Peumans, Marleen; Van Meerbeek, Bart; Lambrechts, Paul

    2010-08-01

    The aim of the study was to compare the clinical performance, quantitative and qualitative wear patterns of conventional hybrid (Tetric Ceram), micro-filled hybrid (Gradia Direct Posterior) and nano-hybrid (Tetric EvoCeram, TEC) posterior composite restorations in a 3-year randomised clinical trial. Sixteen Tetric Ceram, 17 TEC and 16 Gradia Direct Posterior restorations were placed in human molars and evaluated at baseline, 6, 12, 24 and 36 months of clinical service according to US Public Health Service criteria. The gypsum replicas at each recall were used for 3D laser scanning to quantify wear, and the epoxy resin replicas were observed under scanning electron microscope to study the qualitative wear patterns. After 3 years of clinical service, the three hybrid restorative materials performed clinically well in posterior cavities. Within the observation period, the nano-hybrid and micro-hybrid restorations evolved better in polishability with improved surface gloss retention than the conventional hybrid counterpart. The three hybrid composites showed enamel-like vertical wear and cavity-size dependant volume loss magnitude. Qualitatively, while the micro-filled and nano-hybrid composite restorations exhibited signs of fatigue similar to the conventional hybrid composite restorations at heavy occlusal contact area, their light occlusal contact areas showed less surface pitting after 3 years of clinical service.

  16. A Motion-Adaptive Deinterlacer via Hybrid Motion Detection and Edge-Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Li Hsin-Te

    2008-01-01

    Full Text Available Abstract A novel motion-adaptive deinterlacing algorithm with edge-pattern recognition and hybrid motion detection is introduced. The great variety of video contents makes the processing of assorted motion, edges, textures, and the combination of them very difficult with a single algorithm. The edge-pattern recognition algorithm introduced in this paper exhibits the flexibility in processing both textures and edges which need to be separately accomplished by line average and edge-based line average before. Moreover, predicting the neighboring pixels for pattern analysis and interpolation further enhances the adaptability of the edge-pattern recognition unit when motion detection is incorporated. Our hybrid motion detection features accurate detection of fast and slow motion in interlaced video and also the motion with edges. Using only three fields for detection also renders higher temporal correlation for interpolation. The better performance of our deinterlacing algorithm with higher content-adaptability and less memory cost than the state-of-the-art 4-field motion detection algorithms can be seen from the subjective and objective experimental results of the CIF and PAL video sequences.

  17. A Motion-Adaptive Deinterlacer via Hybrid Motion Detection and Edge-Pattern Recognition

    Directory of Open Access Journals (Sweden)

    He-Yuan Lin

    2008-03-01

    Full Text Available A novel motion-adaptive deinterlacing algorithm with edge-pattern recognition and hybrid motion detection is introduced. The great variety of video contents makes the processing of assorted motion, edges, textures, and the combination of them very difficult with a single algorithm. The edge-pattern recognition algorithm introduced in this paper exhibits the flexibility in processing both textures and edges which need to be separately accomplished by line average and edge-based line average before. Moreover, predicting the neighboring pixels for pattern analysis and interpolation further enhances the adaptability of the edge-pattern recognition unit when motion detection is incorporated. Our hybrid motion detection features accurate detection of fast and slow motion in interlaced video and also the motion with edges. Using only three fields for detection also renders higher temporal correlation for interpolation. The better performance of our deinterlacing algorithm with higher content-adaptability and less memory cost than the state-of-the-art 4-field motion detection algorithms can be seen from the subjective and objective experimental results of the CIF and PAL video sequences.

  18. Patterns of hybrid loss of imprinting reveal tissue- and cluster-specific regulation.

    Directory of Open Access Journals (Sweden)

    Christopher D Wiley

    Full Text Available BACKGROUND: Crosses between natural populations of two species of deer mice, Peromyscus maniculatus (BW, and P. polionotus (PO, produce parent-of-origin effects on growth and development. BW females mated to PO males (bwxpo produce growth-retarded but otherwise healthy offspring. In contrast, PO females mated to BW males (POxBW produce overgrown and severely defective offspring. The hybrid phenotypes are pronounced in the placenta and include POxBW conceptuses which lack embryonic structures. Evidence to date links variation in control of genomic imprinting with the hybrid defects, particularly in the POxBW offspring. Establishment of genomic imprinting is typically mediated by gametic DNA methylation at sites known as gDMRs. However, imprinted gene clusters vary in their regulation by gDMR sequences. METHODOLOGY/PRINCIPAL FINDINGS: Here we further assess imprinted gene expression and DNA methylation at different cluster types in order to discern patterns. These data reveal POxBW misexpression at the Kcnq1ot1 and Peg3 clusters, both of which lose ICR methylation in placental tissues. In contrast, some embryonic transcripts (Peg10, Kcnq1ot1 reactivated the silenced allele with little or no loss of DNA methylation. Hybrid brains also display different patterns of imprinting perturbations. Several cluster pairs thought to use analogous regulatory mechanisms are differentially affected in the hybrids. CONCLUSIONS/SIGNIFICANCE: These data reinforce the hypothesis that placental and somatic gene regulation differs significantly, as does that between imprinted gene clusters and between species. That such epigenetic regulatory variation exists in recently diverged species suggests a role in reproductive isolation, and that this variation is likely to be adaptive.

  19. A hybrid finite mixture model for exploring heterogeneous ordering patterns of driver injury severity.

    Science.gov (United States)

    Ma, Lu; Wang, Guan; Yan, Xuedong; Weng, Jinxian

    2016-04-01

    Debates on the ordering patterns of crash injury severity are ongoing in the literature. Models without proper econometrical structures for accommodating the complex ordering patterns of injury severity could result in biased estimations and misinterpretations of factors. This study proposes a hybrid finite mixture (HFM) model aiming to capture heterogeneous ordering patterns of driver injury severity while enhancing modeling flexibility. It attempts to probabilistically partition samples into two groups in which one group represents an unordered/nominal data-generating process while the other represents an ordered data-generating process. Conceptually, the newly developed model offers flexible coefficient settings for mining additional information from crash data, and more importantly it allows the coexistence of multiple ordering patterns for the dependent variable. A thorough modeling performance comparison is conducted between the HFM model, and the multinomial logit (MNL), ordered logit (OL), finite mixture multinomial logit (FMMNL) and finite mixture ordered logit (FMOL) models. According to the empirical results, the HFM model presents a strong ability to extract information from the data, and more importantly to uncover heterogeneous ordering relationships between factors and driver injury severity. In addition, the estimated weight parameter associated with the MNL component in the HFM model is greater than the one associated with the OL component, which indicates a larger likelihood of the unordered pattern than the ordered pattern for driver injury severity.

  20. Oxygen content modulation by nanoscale chemical and electrical patterning in epitaxial SrCoO3-δ (0 < δ ≤ 0.5) thin films

    Science.gov (United States)

    Hu, S.; Seidel, J.

    2016-08-01

    Fast controllable redox reactions in solid materials at room temperature are a promising strategy for enhancing the overall performance and lifetime of many energy technology materials and devices. Easy control of oxygen content is a key concept for the realisation of fast catalysis and bulk diffusion at room temperature. Here, high quality epitaxial brownmillerite SrCoO2.5 thin films have been oxidised to perovskite (P) SrCoO3 with NaClO. X-ray diffraction, scanning probe microscopy and x-ray photoelectron spectroscopy measurements were performed to investigate the structural and electronic changes of the material. The oxidised thin films were found to exhibit distinct morphological changes from an atomically flat terrace structure to forming small nanosized islands with boundaries preferentially in [100] or [010] directions all over the surface, relaxing the in-plane strain imposed by the substrate. The conductivity, or oxygen content, of each single island is confined by these textures, which can be locally patterned even further with electric poling. The high charging level at the island boundaries indicates a magnified electric capacity of SCO thin films, which could be exploited in future device geometries. This finding represents a new way of oxygen modulation with associated self-assembled charge confinement to nanoscale boundaries, offering interesting prospects in nanotechnology applications.

  1. Nanoscale silicon substrate patterns from self-assembly of cylinder forming poly(styrene)-block-poly(dimethylsiloxane) block copolymer on silane functionalized surfaces

    Science.gov (United States)

    Borah, Dipu; Cummins, Cian; Rasappa, Sozaraj; Watson, Scott M. D.; Pike, Andrew R.; Horrocks, Benjamin R.; Fulton, David A.; Houlton, Andrew; Liontos, George; Ntetsikas, Konstantinos; Avgeropoulos, Apostolos; Morris, Michael A.

    2017-01-01

    Poly(styrene)-block-poly(dimethylsiloxane) (PS-b-PDMS) is an excellent block copolymer (BCP) system for self-assembly and inorganic template fabrication because of its high Flory-Huggins parameter (χ ˜ 0.26) at room temperature in comparison to other BCPs, and high selective etch contrast between PS and PDMS block for nanopatterning. In this work, self-assembly in PS-b-PDMS BCP is achieved by combining hydroxyl-terminated poly(dimethylsiloxane) (PDMS-OH) brush surfaces with solvent vapor annealing. As an alternative to standard brush chemistry, we report a simple method based on the use of surfaces functionalized with silane-based self-assembled monolayers (SAMs). A solution-based approach to SAM formation was adopted in this investigation. The influence of the SAM-modified surfaces upon BCP films was compared with polymer brush-based surfaces. The cylinder forming PS-b-PDMS BCP and PDMS-OH polymer brush were synthesized by sequential living anionic polymerization. It was observed that silane SAMs provided the appropriate surface chemistry which, when combined with solvent annealing, led to microphase segregation in the BCP. It was also demonstrated that orientation of the PDMS cylinders may be controlled by judicious choice of the appropriate silane. The PDMS patterns were successfully used as an on-chip etch mask to transfer the BCP pattern to underlying silicon substrate with sub-25 nm silicon nanoscale features. This alternative SAM/BCP approach to nanopattern formation shows promising results, pertinent in the field of nanotechnology, and with much potential for application, such as in the fabrication of nanoimprint lithography stamps, nanofluidic devices or in narrow and multilevel interconnected lines.

  2. Pattern of secure bilateral transactions ensuring power economic dispatch in hybrid electricity markets

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ashwani; Gao, Wenzhong [Department of Electrical and Computer Engineering, Tennessee Tech University, Cookeville, TN 38505 (United States)

    2009-07-15

    This paper proposes a new method for secure bilateral transactions determination ensuring economic power dispatch of the generators using new AC distribution factors for pool and bilateral coordinated markets. The new optimization problem considers simultaneous minimization of deviations from scheduled transactions and fuel cost of the generators in the network. The fuel cost has been obtained for hybrid market model and impact of different percentage of bilateral demand on fuel cost, generation share, and pattern of transactions has also been determined. The impact of optimally located unified power flow controller (UPFC) on the bilateral transactions, fuel cost and generation pattern has also been studied. The results have also been obtained for pool market model. The proposed technique has been applied on IEEE 24-bus reliability test system (RTS). (author)

  3. Cutting force signal pattern recognition using hybrid neural network in end milling

    Institute of Scientific and Technical Information of China (English)

    Song-Tae SEONG; Ko-Tae JO; Young-Moon LEE

    2009-01-01

    Under certain cutting conditions in end milling, the signs of cutting forces change from positive to negative during a revolution of the tool. The change of force direction causes the cutting dynamics to be unstable which results in chatter vibration. Therefore, cutting force signal monitoring and classification are needed to determine the optimal cutting conditions and to improve the efficiency of cut. Artificial neural networks are powerful tools for solving highly complex and nonlinear problems. It can be divided into supervised and unsupervised learning machines based on the availability of a teacher. Hybrid neural network was introduced with both of functions of multilayer perceptron (MLP) trained with the back-propagation algorithm for monitoring and detecting abnormal state, and self organizing feature map (SOFM) for treating huge datum such as image processing and pattern recognition, for predicting and classifying cutting force signal patterns simultaneously. The validity of the results is verified with cutting experiments and simulation tests.

  4. Pattern Recognition in Collective Cognitive Systems: Hybrid Human-Machine Learning (HHML) By Heterogeneous Ensembles

    CERN Document Server

    Dashti, Hesam T; Siahpirani, Alireza F; Tonejc, Jernej; Uilecan, Ioan V; Simas, Tiago; Miranda, Bruno; Ribeiro, Rita; Wang, Liya; Assadi, Amir H

    2010-01-01

    The ubiquitous role of the cyber-infrastructures, such as the WWW, provides myriad opportunities for machine learning and its broad spectrum of application domains taking advantage of digital communication. Pattern classification and feature extraction are among the first applications of machine learning that have received extensive attention. The most remarkable achievements have addressed data sets of moderate-to-large size. The 'data deluge' in the last decade or two has posed new challenges for AI researchers to design new, effective and accurate algorithms for similar tasks using ultra-massive data sets and complex (natural or synthetic) dynamical systems. We propose a novel principled approach to feature extraction in hybrid architectures comprised of humans and machines in networked communication, who collaborate to solve a pre-assigned pattern recognition (feature extraction) task. There are two practical considerations addressed below: (1) Human experts, such as plant biologists or astronomers, often...

  5. Real-time biomimetic Central Pattern Generators in an FPGA for hybrid experiments.

    Science.gov (United States)

    Ambroise, Matthieu; Levi, Timothée; Joucla, Sébastien; Yvert, Blaise; Saïghi, Sylvain

    2013-01-01

    This investigation of the leech heartbeat neural network system led to the development of a low resources, real-time, biomimetic digital hardware for use in hybrid experiments. The leech heartbeat neural network is one of the simplest central pattern generators (CPG). In biology, CPG provide the rhythmic bursts of spikes that form the basis for all muscle contraction orders (heartbeat) and locomotion (walking, running, etc.). The leech neural network system was previously investigated and this CPG formalized in the Hodgkin-Huxley neural model (HH), the most complex devised to date. However, the resources required for a neural model are proportional to its complexity. In response to this issue, this article describes a biomimetic implementation of a network of 240 CPGs in an FPGA (Field Programmable Gate Array), using a simple model (Izhikevich) and proposes a new synapse model: activity-dependent depression synapse. The network implementation architecture operates on a single computation core. This digital system works in real-time, requires few resources, and has the same bursting activity behavior as the complex model. The implementation of this CPG was initially validated by comparing it with a simulation of the complex model. Its activity was then matched with pharmacological data from the rat spinal cord activity. This digital system opens the way for future hybrid experiments and represents an important step toward hybridization of biological tissue and artificial neural networks. This CPG network is also likely to be useful for mimicking the locomotion activity of various animals and developing hybrid experiments for neuroprosthesis development.

  6. Real-time biomimetic Central Pattern Generators into FPGA for hybrid experiments

    Directory of Open Access Journals (Sweden)

    Matthieu eAmbroise

    2013-11-01

    Full Text Available This article investigates the neural network system in the leech heartbeat and develops a real-time biomimetic digital hardware using few-resource implementation for hybrid experiments. The leech heartbeat neural network is one of the most simple central pattern generators (CPG. In biology, CPG provide for rhythmic bursts of spikes and is the basis for all muscles contractions orders (heartbeat and locomotion (walking, running….. The leech neural network system was already investigated and this CPG has been already formalized with Hodgkin-Huxley neural model (HH that is the most complex neuron model. However, the resources needed for a neural model is proportional to its complexity. To answer to this issue, this article describes a biomimetic implementation into FPGA (Field Programmable Gate Array of a network of 240 CPGs using a simple model (Izhikevich model and by proposing a new synapse model: activity dependent depression synapse. The architecture of the network implementation allows working on a single computation core. This digital system works in real-time, needs few resources and has the same bursting activity behavior than complex model. To validate our implementation of this CPG, we compare it firstly with a simulation of the complex model. Then we match its activity with the pharmacological data of the activity of the rat’s spinal cord. This digital system allows future hybrid experiments and will be a great step towards hybridation between biological tissue and artificial neural network. This network of CPG could be also useful for mimic the activity of a different animal locomotion or developing hybrid experiments for neuroprosthesis development.

  7. Length-Bounded Hybrid CPU/GPU Pattern Matching Algorithm for Deep Packet Inspection

    Directory of Open Access Journals (Sweden)

    Yi-Shan Lin

    2017-01-01

    Full Text Available Since frequent communication between applications takes place in high speed networks, deep packet inspection (DPI plays an important role in the network application awareness. The signature-based network intrusion detection system (NIDS contains a DPI technique that examines the incoming packet payloads by employing a pattern matching algorithm that dominates the overall inspection performance. Existing studies focused on implementing efficient pattern matching algorithms by parallel programming on software platforms because of the advantages of lower cost and higher scalability. Either the central processing unit (CPU or the graphic processing unit (GPU were involved. Our studies focused on designing a pattern matching algorithm based on the cooperation between both CPU and GPU. In this paper, we present an enhanced design for our previous work, a length-bounded hybrid CPU/GPU pattern matching algorithm (LHPMA. In the preliminary experiment, the performance and comparison with the previous work are displayed, and the experimental results show that the LHPMA can achieve not only effective CPU/GPU cooperation but also higher throughput than the previous method.

  8. Nanoscale wicking methods and devices

    Science.gov (United States)

    Zhou, Jijie (Inventor); Bronikowski, Michael (Inventor); Noca, Flavio (Inventor); Sansom, Elijah B. (Inventor)

    2011-01-01

    A fluid transport method and fluid transport device are disclosed. Nanoscale fibers disposed in a patterned configuration allow transport of a fluid in absence of an external power source. The device may include two or more fluid transport components having different fluid transport efficiencies. The components may be separated by additional fluid transport components, to control fluid flow.

  9. Early Marine Migration Patterns of Wild Coastal Cutthroat Trout (Oncorhynchus clarki clarki), Steelhead Trout (Oncorhynchus mykiss), and Their Hybrids

    OpenAIRE

    2010-01-01

    BACKGROUND: Hybridization between coastal cutthroat trout (Oncorhynchus clarki clarki) and steelhead or rainbow trout (Oncorhynchus mykiss) has been documented in several streams along the North American west coast. The two species occupy similar freshwater habitats but the anadromous forms differ greatly in the duration of marine residence and migration patterns at sea. Intermediate morphological, physiological, and performance traits have been reported for hybrids but little information has...

  10. Real-time Walking Pattern Generation for a Biped Robot with Hybrid CPG-ZMP Algorithm

    Directory of Open Access Journals (Sweden)

    Bin He

    2014-10-01

    Full Text Available Biped robots have better mobility than conventional wheeled robots. The bio-inspired method based on a central pattern generator (CPG can be used to control biped robot walking in a manner like human beings. However, to achieve stable locomotion, it is difficult to modulate the parameters for the neural networks to coordinate every degree of freedom of the walking robot. The zero moment point (ZMP method is very popular for the stability control of biped robot walking. However, the reference trajectories have low energy efficiency, lack naturalness and need significant offline calculation. This paper presents a new method for biped real-time walking generation using a hybrid CPG-ZMP control algorithm. The method can realize a stable walking pattern by combining the ZMP criterion with rhythmic motion control. The CPG component is designed to generate the desired motion for each robot joint, which is modulated by phase resetting according to foot contact information. By introducing the ZMP location, the activity of the CPG output signal is adjusted to coordinate the limbs’ motion and allow the robot to maintain balance during the process of locomotion. The numerical simulation results show that, compared with the CPG method, the new hybrid CPG-ZMP algorithm can enhance the robustness of the CPG parameters and improve the stability of the robot. In addition, the proposed algorithm is more energy efficient than the ZMP method. The results also demonstrate that the control system can generate an adaptive walking pattern through interactions between the robot, the CPG and the environment.

  11. Nanoscale 2013

    Science.gov (United States)

    Koenders, Ludger; Ducourtieux, Sebastien

    2014-04-01

    The accurate determination of the properties of micro- and nano-structures is essential in research and development. It is also a prerequisite in process control and quality assurance in industry. In most cases, especially at the nanometer range, knowledge of the dimensional properties of structures is the fundamental base, to which further physical properties are linked. Quantitative measurements presuppose reliable and stable instruments, suitable measurement procedures as well as calibration artifacts and methods. This special issue of Measurement Science and Technology presents selected contributions from the NanoScale 2013 seminar held in Paris, France, on 25 and 26 April. It was the 6th Seminar on NanoScale Calibration Standards and Methods and the 10th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized with the Nanometrology Group of the Technical Committee-Length of EURAMET, the Physikalisch-Technische Bundesanstalt and the Laboratoire National de Métrologie et d'Essais. Three satellite meetings related to nanometrology were coupled to the seminar. The first one was an open Symposium on Scanning Probe Microscopy Standardization organized by the ISO/TC 201/SC9 technical committee. The two others were specific meetings focused on two European Metrology Research Projects funded by the European Association of National Metrology Institutes (EURAMET) (see www.euramet.org), the first one focused on the improvement of the traceability for high accuracy devices dealing with sub-nm length measurement and implementing optical interferometers or capacitive sensors (JRP SIB08 subnano), the second one aiming to develop a new metrological traceability for the measurement of the mechanical properties of nano-objects (JRP NEW05 MechProNo). More than 100 experts from industry, calibration laboratories and metrology institutes from around the world joined the NanoScale 2013 Seminar to attend 23 oral and 64 poster

  12. Conformal Array Pattern Synthesis Using a Hybrid WARP/2LB-MOPSO Algorithm

    Directory of Open Access Journals (Sweden)

    Roghieh Karimzadeh Baee

    2012-01-01

    Full Text Available This paper addresses conformal array synthesis as a constrained multiobjective optimization problem. Simultaneous reduction of side lobe level (SLL and cross-polarization (XPL level is aimed with a constraint on main beam direction. A hybrid of weighted alternating reverse projection (WARP and two local best multiobjective particle swarm optimization (2LB-MOPSO is proposed to optimize the pattern. First, the WARP method finds a moderate and feasible solution. Second, 2LB-MOPSO begins with an initial population including the solution of WARP and penalty functions for constraint handling. Involving WARP result in the initial population of 2LB-MOPSO leads to higher convergence rate, avoiding local extermum traps and less sensitivity to penalty functions. Compared to WARP method which stagnates rapidly, the proposed hybrid method gives better SLL and XPL after adequate iterations. In addition, as 2LB-MOPSO offers a set of optimum solutions (Pareto front instead of a single solution, this method provides more degrees of freedom in selection of proper practical arrays. Finally, to examine the mutual coupling consideration in array design, the same procedure was applied ignoring the mutual coupling between elements. The results show that the SLL and XPL strongly depend on mutual coupling.

  13. Learning Design Patterns for Hybrid Synchronous Video-Mediated Learning Environments

    DEFF Research Database (Denmark)

    Weitze, Charlotte Lærke

    2016-01-01

    of their daily practices and also participated in a design-based research project exploring new learning designs for this environment (Weitze, 2015). The teachers’ traditional learning designs were challenged, and this led to altered pedagogical approaches with less group-work and an extensive use of monologue......This article describes an innovative learning environment where remote and face-to-face full-time general upper secondary adult students jointly participate in the same live classes at VUC Storstrøm, an adult learning centre in Denmark. The teachers developed new learning designs as a part......-based teaching. The findings were, however, that the teachers, through pedagogically innovative strategies, developed knowledge about how their pedagogical patterns in this hybrid synchronous learning situation could be supported by an array of additional educational technologies and strategies to create...

  14. Learning Design Patterns for Hybrid Synchronous Video-Mediated Learning Environments

    DEFF Research Database (Denmark)

    Weitze, Charlotte Lærke

    2016-01-01

    -based teaching. The findings were, however, that the teachers, through pedagogically innovative strategies, developed knowledge about how their pedagogical patterns in this hybrid synchronous learning situation could be supported by an array of additional educational technologies and strategies to create......This article describes an innovative learning environment where remote and face-to-face full-time general upper secondary adult students jointly participate in the same live classes at VUC Storstrøm, an adult learning centre in Denmark. The teachers developed new learning designs as a part...... of their daily practices and also participated in a design-based research project exploring new learning designs for this environment (Weitze, 2015). The teachers’ traditional learning designs were challenged, and this led to altered pedagogical approaches with less group-work and an extensive use of monologue...

  15. The effect of fibre layering pattern in resisting bending loads of natural fibre-based hybrid composite materials

    Directory of Open Access Journals (Sweden)

    Jusoh Muhamad Shahirul Mat

    2016-01-01

    Full Text Available The effect of fibre layering pattern and hybridization on the flexural properties of composite hybrid laminates between natural fibres of basalt, jute and flax with synthetic fibre of E-glass reinforced epoxy have been investigated experimentally. Results showed that the effect fibre layering pattern was highly significant on the flexural strength and modulus, which were strongly dependent on the hybrid configuration between sandwich-like (SL and intercalation (IC sequence of fibre layers. In addition, specific modulus based on the variation densities of the hybrid laminates was used to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning on the strength to weight-ratio. Generally, SL sequence of glass/basalt exhibited superior strength and stiffness compared with glass/jute and glass/flax in resisting bending loads. In terms of hybridization effect, glass/jute was found to be the best combination with E-glass compared to the rest of natural fibres investigated in the present study. Hence, the proper stacking sequences and material selection are among predominant factors that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired requirements.

  16. Early marine migration patterns of wild coastal cutthroat trout (Oncorhynchus clarki clarki, steelhead trout (Oncorhynchus mykiss, and their hybrids.

    Directory of Open Access Journals (Sweden)

    Megan E Moore

    Full Text Available BACKGROUND: Hybridization between coastal cutthroat trout (Oncorhynchus clarki clarki and steelhead or rainbow trout (Oncorhynchus mykiss has been documented in several streams along the North American west coast. The two species occupy similar freshwater habitats but the anadromous forms differ greatly in the duration of marine residence and migration patterns at sea. Intermediate morphological, physiological, and performance traits have been reported for hybrids but little information has been published comparing the behavior of hybrids to the pure species. METHODOLOGY/PRINCIPAL FINDINGS: This study used acoustic telemetry to record the movements of 52 cutthroat, 42 steelhead x cutthroat hybrids, and 89 steelhead smolts, all wild, that migrated from Big Beef Creek into Hood Canal (Puget Sound, Washington. Various spatial and temporal metrics were used to compare the behavior of the pure species to their hybrids. Median hybrid residence time, estuary time, and tortuosity values were intermediate compared to the pure species. The median total track distance was greater for hybrids than for either cutthroat or steelhead. At the end of each track, most steelhead (80% were located near or north of the Hood Canal, as expected for this seaward migrating species, whereas most cutthroat (89% were within 8 kilometers of the estuary. Most hybrids (70% were detected leaving Hood Canal, though a substantial percentage (20% remained near the Big Beef Creek estuary. More hybrids (7.5% than pure cutthroat (4.5% or steelhead (0.0% were last detected in the southern reaches of Hood Canal. CONCLUSIONS/SIGNIFICANCE: Given the similarity in freshwater ecology between the species, differences in marine ecology may play an important role in maintaining species integrity in areas of sympatry.

  17. Ellipsometry based imaging techniques for nanoscale characterization of heterogeneous polymer films

    NARCIS (Netherlands)

    Cumurcu, Aysegul

    2014-01-01

    In this thesis, hybrid methods for nanoscale characterization of heterogeneous thin polymer films were discussed. Essentially two ellipsometry based hybrid methods were established or further developed, respectively, namely electrochemical imaging ellipsometry (EC-IE) and scanning near field ellipso

  18. In-situ spectroscopy and nanoscale electronics in superconductor-topological insulator hybrid devices: a combined thin film growth and quantum transport study

    NARCIS (Netherlands)

    Ngabonziza, Prosper

    2016-01-01

    In this dissertation, we presented a combined thin film growth and quantum transport study on superconductor topological insulator hybrid devices. Understanding of the electronic properties of topological insulators (TIs), their preparation in high quality thin film form and their interaction with o

  19. Combined hybridization and mitochondrial capture shape complex phylogeographic patterns in hybridogenetic Cataglyphis desert ants.

    Science.gov (United States)

    Eyer, P A; Leniaud, L; Tinaut, A; Aron, S

    2016-12-01

    Some species of Cataglyphis desert ants have evolved a hybridogenetic mode of reproduction at the social scale. In hybridogenetic populations, two distinct genetic lineages coexist. Non-reproductive offspring (workers) are hybrids of the two lineages, whereas sexual offspring (males and new queens) are produced by parthenogenesis and belong to the mother queen lineage. How this unusual reproductive system affects phylogeographic patterns and speciation processes remains completely unknown to date. Using one mitochondrial and four nuclear genes, we examined the phylogenetic relationships between three species of Cataglyphis (C. hispanica, C. humeya and C. velox) where complex DNA inheritance through social hybridogenesis may challenge phylogenetic inference. Our results bring two important insights. First, our data confirm a hybridogenetic mode of reproduction across the whole distribution range of the species C. hispanica. In contrast, they do not provide support for hybridogenesis in the populations sampled of C. humeya and C. velox. This suggests that these populations are not hybridogenetic, or that hybridogenesis is too recent to result in reciprocally monophyletic lineages on nuclear genes. Second, due to mitochondrial introgression between lineages (Darras and Aron, 2015), the faster-evolving COI marker is not lineage specific, hence, unsuitable to further investigate the segregation of lineages in the species studied. Different mitochondrial haplotypes occur in each locality sampled, resulting in strongly structured populations. This micro-allopatric structure leads to over-splitting species delimitation on mitochondrial gene, as every locality could potentially be considered a putative species; haploweb analyses of nuclear markers, however, yield species delimitations that are consistent with morphology. Overall, this study highlights how social hybridogenesis varies across species and shapes complex phylogeographic patterns.

  20. Circadian patterns of xylem sap properties and their covariation with plant hydraulic traits in hybrid aspen.

    Science.gov (United States)

    Meitern, Annika; Õunapuu-Pikas, Eele; Sellin, Arne

    2017-06-01

    Physiological processes taking place in plants are subject to diverse circadian patterns but some of them are poorly documented in natural conditions. The daily dynamics of physico-chemical properties of xylem sap and their covariation with tree hydraulic traits were investigated in hybrid aspen (Populus tremula L.×P. tremuloides Michx) in field conditions in order to clarify which environmental drivers govern the daily variation in these parameters. K(+) concentration ([K(+)]), electrical conductivity (σsap), osmolality (Osm) and pH of the xylem sap, as well as branch hydraulic traits, were measured in the field over 24-h cycles. All studied xylem sap properties and hydraulic characteristics including whole-branch (Kwb), leaf blade (Klb) and petiole hydraulic conductances (KP) showed clear daily dynamics. Air temperature (TA) and photosynthetic photon flux density (PPFD), but also water vapour pressure deficit (VPD) and relative humidity (RH), had significant impacts on KwbKlb, KP, [K(+)] and σsap. Osm varied only with light intensity, while KB varied depending on atmospheric evaporative demand expressed as TA, VPD or RH. Xylem sap pH depended inversely on soil water potential (ΨS) and during daylight also on VPD. Although soil water content was close to saturation during the study period, ΨS influenced also [K(+)] and σsap. The present study presents evidence of coupling between circadian patterns of xylem sap properties and plant hydraulic conductance providing adequate water supply to foliage under environmental conditions characterised by diurnal variation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  1. A Hybrid CPU/GPU Pattern-Matching Algorithm for Deep Packet Inspection.

    Directory of Open Access Journals (Sweden)

    Chun-Liang Lee

    Full Text Available The large quantities of data now being transferred via high-speed networks have made deep packet inspection indispensable for security purposes. Scalable and low-cost signature-based network intrusion detection systems have been developed for deep packet inspection for various software platforms. Traditional approaches that only involve central processing units (CPUs are now considered inadequate in terms of inspection speed. Graphic processing units (GPUs have superior parallel processing power, but transmission bottlenecks can reduce optimal GPU efficiency. In this paper we describe our proposal for a hybrid CPU/GPU pattern-matching algorithm (HPMA that divides and distributes the packet-inspecting workload between a CPU and GPU. All packets are initially inspected by the CPU and filtered using a simple pre-filtering algorithm, and packets that might contain malicious content are sent to the GPU for further inspection. Test results indicate that in terms of random payload traffic, the matching speed of our proposed algorithm was 3.4 times and 2.7 times faster than those of the AC-CPU and AC-GPU algorithms, respectively. Further, HPMA achieved higher energy efficiency than the other tested algorithms.

  2. A Hybrid CPU/GPU Pattern-Matching Algorithm for Deep Packet Inspection.

    Science.gov (United States)

    Lee, Chun-Liang; Lin, Yi-Shan; Chen, Yaw-Chung

    2015-01-01

    The large quantities of data now being transferred via high-speed networks have made deep packet inspection indispensable for security purposes. Scalable and low-cost signature-based network intrusion detection systems have been developed for deep packet inspection for various software platforms. Traditional approaches that only involve central processing units (CPUs) are now considered inadequate in terms of inspection speed. Graphic processing units (GPUs) have superior parallel processing power, but transmission bottlenecks can reduce optimal GPU efficiency. In this paper we describe our proposal for a hybrid CPU/GPU pattern-matching algorithm (HPMA) that divides and distributes the packet-inspecting workload between a CPU and GPU. All packets are initially inspected by the CPU and filtered using a simple pre-filtering algorithm, and packets that might contain malicious content are sent to the GPU for further inspection. Test results indicate that in terms of random payload traffic, the matching speed of our proposed algorithm was 3.4 times and 2.7 times faster than those of the AC-CPU and AC-GPU algorithms, respectively. Further, HPMA achieved higher energy efficiency than the other tested algorithms.

  3. Identification of dietary patterns associated with obesity in a nationally representative survey of Canadian adults: application of a priori, hybrid, and simplified dietary pattern techniques.

    Science.gov (United States)

    Jessri, Mahsa; Wolfinger, Russell D; Lou, Wendy Y; L'Abbé, Mary R

    2017-03-01

    Background: Analyzing the effects of dietary patterns is an important approach for examining the complex role of nutrition in the etiology of obesity and chronic diseases.Objectives: The objectives of this study were to characterize the dietary patterns of Canadians with the use of a priori, hybrid, and simplified dietary pattern techniques, and to compare the associations of these patterns with obesity risk in individuals with and without chronic diseases (unhealthy and healthy obesity).Design: Dietary recalls from 11,748 participants (≥18 y of age) in the cross-sectional, nationally representative Canadian Community Health Survey 2.2 were used. A priori dietary pattern was characterized with the use of the previously validated 2015 Dietary Guidelines for Americans Adherence Index (DGAI). Weighted partial least squares (hybrid method) was used to derive an energy-dense (ED), high-fat (HF), low-fiber density (LFD) dietary pattern with the use of 38 food groups. The associations of derived dietary patterns with disease outcomes were then tested with the use of multinomial logistic regression.Results: An ED, HF, and LFD dietary pattern had high positive loadings for fast foods, carbonated drinks, and refined grains, and high negative loadings for whole fruits and vegetables (≥|0.17|). Food groups with a high loading were summed to form a simplified dietary pattern score. Moving from the first (healthiest) to the fourth (least healthy) quartiles of the ED, HF, and LFD pattern and the simplified dietary pattern scores was associated with increasingly elevated ORs for unhealthy obesity, with individuals in quartile 4 having an OR of 2.57 (95% CI: 1.75, 3.76) and 2.73 (95% CI: 1.88, 3.98), respectively (P-trend patterns with healthy obesity and unhealthy nonobesity were weaker, albeit significant.Conclusions: Consuming an ED, HF, and LFD dietary pattern and lack of adherence to the recommendations of the 2015 DGAI were associated with a significantly higher risk of

  4. Charge transport in nanoscale junctions.

    Science.gov (United States)

    Albrecht, Tim; Kornyshev, Alexei; Bjørnholm, Thomas

    2008-09-03

    the molecular level. Nanoscale charge transport experiments in ionic liquids extend the field to high temperatures and to systems with intriguing interfacial potential distributions. Other directions may include dye-sensitized solar cells, new sensor applications and diagnostic tools for the study of surface-bound single molecules. Another motivation for this special issue is thus to highlight activities across different research communities with nanoscale charge transport as a common denominator. This special issue gathers 27 articles by scientists from the United States, Germany, the UK, Denmark, Russia, France, Israel, Canada, Australia, Sweden, Switzerland, the Netherlands, Belgium and Singapore; it gives us a flavour of the current state-of-the-art of this diverse research area. While based on contributions from many renowned groups and institutions, it obviously cannot claim to represent all groups active in this very broad area. Moreover, a number of world-leading groups were unable to take part in this project within the allocated time limit. Nevertheless, we regard the current selection of papers to be representative enough for the reader to draw their own conclusions about the current status of the field. Each paper is original and has its own merit, as all papers in Journal of Physics: Condensed Matter special issues are subjected to the same scrutiny as regular contributions. The Guest Editors have deliberately not defined the specific subjects covered in this issue. These came out logically from the development of this area, for example: 'Traditional' solid state nanojunctions based on adsorbed layers, oxide films or nanowires sandwiched between two electrodes: effects of molecular structure (aromaticity, anchoring groups), symmetry, orientation, dynamics (noise patterns) and current-induced heating. Various 'physical effects': inelastic tunnelling and Coulomb blockade, polaron effects, switching modes, and negative differential resistance; the role of

  5. Bio-Organic Nanotechnology: Using Proteins and Synthetic Polymers for Nanoscale Devices

    Science.gov (United States)

    Molnar, Linda K.; Xu, Ting; Trent, Jonathan D.; Russell, Thomas P.

    2003-01-01

    While the ability of proteins to self-assemble makes them powerful tools in nanotechnology, in biological systems protein-based structures ultimately depend on the context in which they form. We combine the self-assembling properties of synthetic diblock copolymers and proteins to construct intricately ordered, three-dimensional polymer protein structures with the ultimate goal of forming nano-scale devices. This hybrid approach takes advantage of the capabilities of organic polymer chemistry to build ordered structures and the capabilities of genetic engineering to create proteins that are selective for inorganic or organic substrates. Here, microphase-separated block copolymers coupled with genetically engineered heat shock proteins are used to produce nano-scale patterning that maximizes the potential for both increased structural complexity and integrity.

  6. Intergeneric hybridization and C-banding patterns in Hordelymus (Triticeae, Poaceae)

    DEFF Research Database (Denmark)

    Bothmer, R. von; Lu, B.-R.; Linde-Laursen, I.

    1994-01-01

    Crosses of Hordelymus europaeus (2n = 4x = 28) with four genera in the Triticeae were attempted. Adult hybrids were obtained in combinations with Hordeum bogdanii (2x), Hordeum depressum (4x), and Secale cereale (2x). The meiotic pairing was very low in the hybrids with H. bogdanii and Secale cer...

  7. Assessing patterns of hybridization between North Atlantic eels using diagnostic single-nucleotide polymorphisms

    DEFF Research Database (Denmark)

    Pujolar, José Martin; Jacobsen, M.W.; Als, Thomas Damm

    2014-01-01

    The two North Atlantic eel species, the European eel (Anguilla anguilla) and the American eel (Anguilla rostrata), spawn in partial sympatry in the Sargasso Sea, providing ample opportunity to interbreed. In this study, we used a RAD (Restriction site Associated DNA) sequencing approach to identify...... eel) collected in the Sargasso Sea. Our SNP survey showed that the majority of Icelandic eels are pure European eels but there is also an important contribution of individuals of admixed ancestry (10.7%). Although most of the hybrids were identified as F1 hybrids from European eel female × American......, no hybrids were observed in the Faroe Islands, the closest bodies of land to Iceland. It is possible that hybrids show an intermediate migratory behaviour between the two parental species that ultimately brings hybrid larvae to the shores of Iceland, situated roughly halfway between the Sargasso Sea...

  8. The Effects of Land Use Patterns on Tour Type Choice. The Application of a Hybrid Choice Model

    DEFF Research Database (Denmark)

    de Abreu e Silva, João; Sottile, Eleonora; Cherchi, Elisabetta

    2014-01-01

    The relations between travel behavior and land use patterns have been the object of intensive research in the last two decades. Due to their immediate policy implications, mode choice and vehicle miles of travel (VMT) have been the main focus of attention. Other relevant dimensions, like trip...... chaining, tour type choice, and number of tours have received less attention. This work aims to contribute to the research dealing with the role of land use patterns on tour type choice. To pursue this objective, a tour type choice is modeled using a hybrid choice model that allows simulating the effect...

  9. Emerging ferroelectric transistors with nanoscale channel materials: the possibilities, the limitations

    Science.gov (United States)

    Hong, Xia

    2016-03-01

    Combining the nonvolatile, locally switchable polarization field of a ferroelectric thin film with a nanoscale electronic material in a field effect transistor structure offers the opportunity to examine and control a rich variety of mesoscopic phenomena and interface coupling. It is also possible to introduce new phases and functionalities into these hybrid systems through rational design. This paper reviews two rapidly progressing branches in the field of ferroelectric transistors, which employ two distinct classes of nanoscale electronic materials as the conducting channel, the two-dimensional (2D) electron gas graphene and the strongly correlated transition metal oxide thin films. The topics covered include the basic device physics, novel phenomena emerging in the hybrid systems, critical mechanisms that control the magnitude and stability of the field effect modulation and the mobility of the channel material, potential device applications, and the performance limitations of these devices due to the complex interface interactions and challenges in achieving controlled materials properties. Possible future directions for this field are also outlined, including local ferroelectric gate control via nanoscale domain patterning and incorporating other emergent materials in this device concept, such as the simple binary ferroelectrics, layered 2D transition metal dichalcogenides, and the 4d and 5d heavy metal compounds with strong spin-orbit coupling.

  10. A Method for Identification of Driving Patterns in Hybrid Electric Vehicles Based on a LVQ Neural Network

    Directory of Open Access Journals (Sweden)

    Xiaowei Zhang

    2012-09-01

    Full Text Available Driving patterns exert an important influence on the fuel economy of vehicles, especially hybrid electric vehicles. This paper aims to build a method to identify driving patterns with enough accuracy and less sampling time compared than other driving pattern recognition algorithms. Firstly a driving pattern identifier based on a Learning Vector Quantization neural network is established to analyze six selected representative standard driving cycles. Micro-trip extraction and Principal Component Analysis methods are applied to ensure the magnitude and diversity of the training samples. Then via Matlab/Simulink, sample training simulation is conducted to determine the minimum neuron number of the Learning Vector Quantization neural network and, as a result, to help simplify the identifier model structure and reduce the data convergence time. Simulation results have proved the feasibility of this method, which decreases the sampling window length from about 250–300 s to 120 s with an acceptable accuracy. The driving pattern identifier is further used in an optimized co-simulation together with a parallel hybrid vehicle model and improves the fuel economy by about 8%.

  11. Implications of driving patterns on well-to-wheel performance of plug-in hybrid electric vehicles.

    Science.gov (United States)

    Raykin, Leon; MacLean, Heather L; Roorda, Matthew J

    2012-06-05

    This study examines how driving patterns (distance and conditions) and the electricity generation supply interact to impact well-to-wheel (WTW) energy use and greenhouse gas (GHG) emissions of plug-in hybrid electric vehicles (PHEVs). The WTW performance of a PHEV is compared with that of a similar (nonplug-in) gasoline hybrid electric vehicle and internal combustion engine vehicle (ICEV). Driving PHEVs for short distances between recharging generally results in lower WTW total and fossil energy use and GHG emissions per kilometer compared to driving long distances, but the extent of the reductions depends on the electricity supply. For example, the shortest driving pattern in this study with hydroelectricity uses 81% less fossil energy than the longest driving pattern. However, the shortest driving pattern with coal-based electricity uses only 28% less fossil energy. Similar trends are observed in reductions relative to the nonplug-in vehicles. Irrespective of the electricity supply, PHEVs result in greater reductions in WTW energy use and GHG emissions relative to ICEVs for city than highway driving conditions. PHEVs charging from coal facilities only reduce WTW energy use and GHG emissions relative to ICEVs for certain favorable driving conditions. The study results have implications for environmentally beneficial PHEV adoption and usage patterns.

  12. Nanoscale thermal probing

    Directory of Open Access Journals (Sweden)

    Yanan Yue

    2012-03-01

    Full Text Available Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem.

  13. Hybrid selective surface hydrophilization and froth flotation separation of hazardous chlorinated plastics from E-waste with novel nanoscale metallic calcium composite.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Heo, Je Haeng; Park, Min Hee

    2016-04-05

    Treatment by a nanometallic Ca/CaO composite has been found to selectively hydrophilize the surface of polyvinyl chloride (PVC), enhancing its wettability and thereby promoting its separation from E-waste plastics by means of froth flotation. The treatment considerably decreased the water contact angle of PVC, by about 18°. The SEM images of the PVC plastic after treatment displayed significant changes in their surface morphology compared to other plastics. The SEM-EDS results reveal that a markedly decrease of [Cl] concentration simultaneously with dramatic increase of [O] on the surface of the PCV samples. XPS results further confirmed an increase of hydrophilic functional groups on the PVC surface. Froth flotation at 100rpm mixing speed was found to be optimal, separating 100% of the PVC into a settled fraction of 96.4% purity even when the plastics fed into the reactor were of nonuniform size and shape. The total recovery of PVC-free plastics in E-waste reached nearly 100% in the floated fraction, significantly improved from the 20.5wt% of light plastics that can be recovered by means of conventional wet gravity separation. The hybrid method of nanometallic Ca/CaO treatment and froth flotation is effective in the separation of hazardous chlorinated plastics from E-waste plastics. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Hybridization between Yellowstone cutthroat trout and rainbow trout alters the expression of muscle growth-related genes and their relationships with growth patterns

    Science.gov (United States)

    Ostberg, Carl O.; Chase, Dorothy M.; Hauser, Lorenz

    2015-01-01

    Hybridization creates novel gene combinations that may generate important evolutionary novelty, but may also reduce existing adaptation by interrupting inherent biological processes, such as genotype-environment interactions. Hybridization often causes substantial change in patterns of gene expression, which, in turn, may cause phenotypic change. Rainbow trout (Oncorhynchus mykiss) and cutthroat trout (O. clarkii) produce viable hybrids in the wild, and introgressive hybridization with introduced rainbow trout is a major conservation concern for native cutthroat trout. The two species differ in body shape, which is likely an evolutionary adaptation to their native environments, and their hybrids tend to show intermediate morphology. The characterization of gene expression patterns may provide insights on the genetic basis of hybrid and parental morphologies, as well as on the ecological performance of hybrids in the wild. Here, we evaluated the expression of eight growth-related genes (MSTN-1a, MSTN-1b, MyoD1a, MyoD1b, MRF-4, IGF-1, IGF-2, and CAST-L) and the relationship of these genes with growth traits (length, weight, and condition factor) in six line crosses: both parental species, both reciprocal F1 hybrids, and both first-generation backcrosses (F1 x rainbow trout and F1 x cutthroat trout). Four of these genes were differentially expressed among rainbow, cutthroat, and their hybrids. Transcript abundance was significantly correlated with growth traits across the parent species, but not across hybrids. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic adaptations.

  15. Hybridization between Yellowstone Cutthroat Trout and Rainbow Trout Alters the Expression of Muscle Growth-Related Genes and Their Relationships with Growth Patterns.

    Directory of Open Access Journals (Sweden)

    Carl O Ostberg

    Full Text Available Hybridization creates novel gene combinations that may generate important evolutionary novelty, but may also reduce existing adaptation by interrupting inherent biological processes, such as genotype-environment interactions. Hybridization often causes substantial change in patterns of gene expression, which, in turn, may cause phenotypic change. Rainbow trout (Oncorhynchus mykiss and cutthroat trout (O. clarkii produce viable hybrids in the wild, and introgressive hybridization with introduced rainbow trout is a major conservation concern for native cutthroat trout. The two species differ in body shape, which is likely an evolutionary adaptation to their native environments, and their hybrids tend to show intermediate morphology. The characterization of gene expression patterns may provide insights on the genetic basis of hybrid and parental morphologies, as well as on the ecological performance of hybrids in the wild. Here, we evaluated the expression of eight growth-related genes (MSTN-1a, MSTN-1b, MyoD1a, MyoD1b, MRF-4, IGF-1, IGF-2, and CAST-L and the relationship of these genes with growth traits (length, weight, and condition factor in six line crosses: both parental species, both reciprocal F1 hybrids, and both first-generation backcrosses (F1 x rainbow trout and F1 x cutthroat trout. Four of these genes were differentially expressed among rainbow, cutthroat, and their hybrids. Transcript abundance was significantly correlated with growth traits across the parent species, but not across hybrids. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic adaptations.

  16. Hybridization between Yellowstone Cutthroat Trout and Rainbow Trout Alters the Expression of Muscle Growth-Related Genes and Their Relationships with Growth Patterns.

    Science.gov (United States)

    Ostberg, Carl O; Chase, Dorothy M; Hauser, Lorenz

    2015-01-01

    Hybridization creates novel gene combinations that may generate important evolutionary novelty, but may also reduce existing adaptation by interrupting inherent biological processes, such as genotype-environment interactions. Hybridization often causes substantial change in patterns of gene expression, which, in turn, may cause phenotypic change. Rainbow trout (Oncorhynchus mykiss) and cutthroat trout (O. clarkii) produce viable hybrids in the wild, and introgressive hybridization with introduced rainbow trout is a major conservation concern for native cutthroat trout. The two species differ in body shape, which is likely an evolutionary adaptation to their native environments, and their hybrids tend to show intermediate morphology. The characterization of gene expression patterns may provide insights on the genetic basis of hybrid and parental morphologies, as well as on the ecological performance of hybrids in the wild. Here, we evaluated the expression of eight growth-related genes (MSTN-1a, MSTN-1b, MyoD1a, MyoD1b, MRF-4, IGF-1, IGF-2, and CAST-L) and the relationship of these genes with growth traits (length, weight, and condition factor) in six line crosses: both parental species, both reciprocal F1 hybrids, and both first-generation backcrosses (F1 x rainbow trout and F1 x cutthroat trout). Four of these genes were differentially expressed among rainbow, cutthroat, and their hybrids. Transcript abundance was significantly correlated with growth traits across the parent species, but not across hybrids. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic adaptations.

  17. Hybrid fault patterns for the diagnosis of gas turbine component degradation

    Energy Technology Data Exchange (ETDEWEB)

    Kubiak S, J [Instituto Politecnico Nacional, Mexico D.F. (Mexico); Gonzalez R, G; Garcia G, A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Gomez Mancilla, G [Universidad Autonoma del Estado de Morelos, Cuernavaca, Morelos (Mexico); Urquiza B, G [Instituto Politecnico Nacional, Mexico D.F. (Mexico)

    2005-04-15

    A degree of wearing out or scaling of the internal components (blading, seals, etc.) can be estimated analyzing the efficiency of the turbo compressor. The wearing out or deposits on the blade or seal deterioration affects the efficiency of the machine which in turn compared to a reference data permits to identify faulty components or a group of components and a degree of their deterioration. However a precision of this identification can be improved involving vibration analysis. It is important to make this identification on line thus facilitating constructing an appropriate plan for a major overhaul. On the other hand, wearing out of the blades changes their natural frequencies and vibration spectrum; seals deterioration are caused by excessive rotor vibration or casing distortion mostly during start-ups. Analyzing simultaneously the efficiency and vibrations the faults and their locations can be identified more precisely. Analogrithm for identification of some faults of the gas turbine using hybrid patterns (efficiency vibration) is developed. [Spanish] El grado de desgaste o incrustacion en los componentes internos de un turbocompresor (alabes, sellos, etc.) puede ser estimado mediante el analisis de su eficiencia. El desgaste depositos en los alabes o el deterioro de los sellos afectan la eficiencia de la maquina la cual comparando con las especificaciones permite identificar componentes defectuosos o a un grupo de ellos y un indice de su degradacion. Sin embargo puede lograrse una identificacion mas precisa cuando se involucra el analisis de su respuesta vibratoria. Es importante hacer dicha identificacion en-linea ya que facilita la elaboracion de un plan apropiado para el mantenimiento general. Por otro lado, el desgaste de los alabes cambia su frecuencia natural y su espectro de vibracion; el deterioro de los sellos es causado por la excesiva vibracion del rotor o la distorsion de la cubierta, sobre todo durante los arranques. Analizando simultaneamente la

  18. Characteristic LDH isozyme electrophoretic patterns in six flatfish species in the Trondheimsfjord, Norway and their utility for the detection of natural species hybrids

    KAUST Repository

    He, Song

    2014-11-19

    Abstract: LDH isozyme electrophoretic patterns among 621 specimens of six different flatfish species collected in the Trondheimsfjord, Norway, were characterized by using the isoelectric focusing in polyacrylamide gel (IFPAG) technique. The LDH locus appears to be a reliable tool for species identification in the Trondheimsfjord flatfishes. Hence, these patterns were used to detect and identify potential hybrids, together with morphological traits. Among all the specimens collected during this study no hybrids were detected. From the actual numbers analysed, the natural hybridization rate between European plaice and European flounder in the Trondheimsfjord can be roughly estimated to be less than 1%. This is substantially lower than corresponding values reported from Baltic and Danish waters.

  19. Patterns of hybridization among cutthroat trout and rainbow trout in northern Rocky Mountain streams.

    Science.gov (United States)

    McKelvey, Kevin S; Young, Michael K; Wilcox, Taylor M; Bingham, Daniel M; Pilgrim, Kristine L; Schwartz, Michael K

    2016-02-01

    Introgressive hybridization between native and introduced species is a growing conservation concern. For native cutthroat trout and introduced rainbow trout in western North America, this process is thought to lead to the formation of hybrid swarms and the loss of monophyletic evolutionary lineages. Previous studies of this phenomenon, however, indicated that hybrid swarms were rare except when native and introduced forms of cutthroat trout co-occurred. We used a panel of 86 diagnostic, single nucleotide polymorphisms to evaluate the genetic composition of 3865 fish captured in 188 locations on 129 streams distributed across western Montana and northern Idaho. Although introgression was common and only 37% of the sites were occupied solely by parental westslope cutthroat trout, levels of hybridization were generally low. Of the 188 sites sampled, 73% contained ≤5% rainbow trout alleles and 58% had ≤1% rainbow trout alleles. Overall, 72% of specimens were nonadmixed westslope cutthroat trout, and an additional 3.5% were nonadmixed rainbow trout. Samples from seven sites met our criteria for hybrid swarms, that is, an absence of nonadmixed individuals and a random distribution of alleles within the sample; most (6/7) were associated with introgression by Yellowstone cutthroat trout. In streams with multiple sites, upstream locations exhibited less introgression than downstream locations. We conclude that although the widespread introduction of nonnative trout within the historical range of westslope cutthroat trout has increased the incidence of introgression, sites containing nonadmixed populations of this taxon are common and broadly distributed.

  20. New polyoxometalates containing hybrid polymers and their potential for nano-patterning.

    Science.gov (United States)

    Kalyani, Vishwanath; Satyanarayana, V S V; Singh, Vikram; Pradeep, Chullikkattil P; Ghosh, Subrata; Sharma, Satinder K; Gonsalves, Kenneth E

    2015-01-26

    Two new polyoxometalate (POM)-based hybrid monomers (Bu4 N)5 (H)[P2 V3 W15 O59 {(OCH2 )3 CNHCO(CH3 )CCH2 }] (2) and (S(CH3 )2 C6 H4 OCOC(CH3 )=CH2 )6 [PV  2Mo10 O40 ] (5) were developed by grafting polymerizable organic units covalently or electrostatically onto Wells-Dawson and Keggin-type clusters and were characterized by analytical and spectroscopic techniques including ESI-MS and/or single-crystal X-ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldimethylsulfonium triflate (MAPDST) and/or methylmethacrylate (MMA) yielded a new series of POM/polymer hybrids that were characterized by (1) H, (31) P NMR and IR spectroscopic techniques, gel-permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photoresists using electron beam (E-beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.

  1. AFM study of excimer laser patterning of block-copolymer: Creation of ordered hierarchical, hybrid, or recessed structures

    Science.gov (United States)

    Švanda, Jan; Siegel, Jakub; Švorčík, Vaclav; Lyutakov, Oleksiy

    2016-05-01

    We report fabrication of the varied range of hierarchical structures by combining bottom-up self-assembly of block copolymer poly(styrene-block-vinylpyridine) (PS-b-P4VP) with top-down excimer laser patterning method. Different procedures were tested, where laser treatment was applied before phase separation and after phase separation or phase separation and surface reconstruction. Laser treatment was performed using either polarized laser light with the aim to create periodical pattern on polymer surface or non-polarized light for preferential removing of polystyrene (PS) part from PS-b-P4VP. Additionally, dye was introduced into one part of block copolymer (P4VP) with the aim to modify its response to laser light. Resulting structures were analyzed by XPS, UV-vis and AFM techniques. Application of polarized laser light leads to creation of structures with hierarchical, recessed or hybrid geometries. Non-polarized laser beam allows pronouncing the block copolymer phase separated structure. Tuning the order of steps or individual step conditions enables the efficient reorientation of block-copolymer domain at large scale, fabrication of hierarchical, hybrid or recessed structures. The obtained structures can find potential applications in nanotechnology, photonics, plasmonics, information storage, optical devices, sensors and smart surfaces.

  2. Spintronics in nanoscale devices

    CERN Document Server

    Hedin, Eric R

    2013-01-01

    By exploiting the novel properties of quantum dots and nanoscale Aharonov-Bohm rings together with the electronic and magnetic properties of various semiconductor materials and graphene, researchers have conducted numerous theoretical and computational modeling studies and experimental tests that show promising behavior for spintronics applications. Spin polarization and spin-filtering capabilities and the ability to manipulate the electron spin state through external magnetic or electric fields have demonstrated the promise of workable nanoscale devices for computing and memory applications.

  3. Preparation of patterned graphene-ZnO hybrid nanoflower and nanorods on ITO surface

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Sin Tee; Umar, Marjoni Imamora Ali; Ginting, Riski Titian; Yahaya, Muhammad; Yap, Chi Chin [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Umar, Akrajas Ali; Salleh, Muhamad Mat; Majlis, Burhanuddin Yeop; Naumar, Fitri Yenni [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2013-11-27

    Hybrid ZnO nanostructure with controlled morphology have been proved to enhance the physical and chemical properties of the material and used as photodiode and sensor. In this paper, hybrid graphene-ZnO nanoflower and nanorods have been successfully synthesized via a seed mediated method with micropatterned ZnO nanoseed treated with multilayer graphene (MLG) in a hydrothermal process. In typical process, the ZnO nanoseeds with and without resists were spin coated with a multilayer graphene prior to the growth process. The treated seed was then used to grow the ZnO nanostructures in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate and hexamethylenetetramine. The growth process was carried out inside an autoclave at temperature 70 °C. The growth time was 4 h. It was proved that the MLG treatment on micropatterning substrate may induce new morphology formation of ZnO nanostructure. It is expected that the heteroepitaxy reaction occurred between the MLG and ZnO interface. This presence method can be used as an alternative approach to control the morphology of hybrid ZnO nanostructure growth.

  4. Integrated nanoscale tools for interrogating living cells

    Science.gov (United States)

    Jorgolli, Marsela

    The development of next-generation, nanoscale technologies that interface biological systems will pave the way towards new understanding of such complex systems. Nanowires -- one-dimensional nanoscale structures -- have shown unique potential as an ideal physical interface to biological systems. Herein, we focus on the development of nanowire-based devices that can enable a wide variety of biological studies. First, we built upon standard nanofabrication techniques to optimize nanowire devices, resulting in perfectly ordered arrays of both opaque (Silicon) and transparent (Silicon dioxide) nanowires with user defined structural profile, densities, and overall patterns, as well as high sample consistency and large scale production. The high-precision and well-controlled fabrication method in conjunction with additional technologies laid the foundation for the generation of highly specialized platforms for imaging, electrochemical interrogation, and molecular biology. Next, we utilized nanowires as the fundamental structure in the development of integrated nanoelectronic platforms to directly interrogate the electrical activity of biological systems. Initially, we generated a scalable intracellular electrode platform based on vertical nanowires that allows for parallel electrical interfacing to multiple mammalian neurons. Our prototype device consisted of 16 individually addressable stimulation/recording sites, each containing an array of 9 electrically active silicon nanowires. We showed that these vertical nanowire electrode arrays could intracellularly record and stimulate neuronal activity in dissociated cultures of rat cortical neurons similar to patch clamp electrodes. In addition, we used our intracellular electrode platform to measure multiple individual synaptic connections, which enables the reconstruction of the functional connectivity maps of neuronal circuits. In order to expand and improve the capability of this functional prototype device we designed

  5. Gamete production patterns, ploidy, and population genetics reveal evolutionary significant units in hybrid water frogs (Pelophylax esculentus).

    Science.gov (United States)

    Pruvost, Nicolas B M; Hoffmann, Alexandra; Reyer, Heinz-Ulrich

    2013-09-01

    The European water frog Pelophylax esculentus is a natural hybrid between P. lessonae (genotype LL) and P. ridibundus (RR). It reproduces through hybridogenesis, eliminating one parental genome from its germline and producing gametes containing the genome of the other parental species. According to previous studies, this elimination and transmission pattern is very diverse. In mixed populations, where only diploid hybrids (LR) live in sympatry and mate with one or both parental species, the excluded genome varies among regions, and the remaining genome is transmitted clonally to haploid gametes. In all-hybrid populations consisting of diploid (LR) and triploid (LLR and/or LRR) frogs, diploid individuals also produce gametes clonally (1n in males, 2n in females), whereas triploids eliminate the genome they have in single copy and produce haploid gametes containing the recombined other genome. However, here, too, regional differences seem to exist, and some triploids have been reported to produce diploid gametes. In order to systematically study such regional and genotype differences in gamete production, their potential origin, and their consequences for the breeding system, we sampled frogs from five populations in three European countries, performed crossing experiments, and investigated the genetic variation through microsatellite analysis. For four populations, one in Poland, two in Germany, and one in Slovakia, our results confirmed the elimination and transmission pattern described above. In one Slovakian population, however, we found a totally different pattern. Here, triploid males (LLR) produce sperm with a clonally transmitted diploid LL genome, rather than a haploid recombined L genome, and LR females clonally produce haploid R eggs, rather than diploid LR eggs. These differences among the populations in gamete production go along with differences in genomotype composition, breeding system (i.e., the way triploids are produced), and genetic variation

  6. Acoustic-Based Cutting Pattern Recognition for Shearer through Fuzzy C-Means and a Hybrid Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2016-10-01

    Full Text Available As the conventional cutting pattern recognition methods for shearer are huge in size, have low recognition reliability and an inconvenient contacting measurement method, a fast and reliable coal-rock cutting pattern recognition system is always a baffling problem worldwide. However, the recognition rate has a direct relation with the outputs of coal mining and the safety quality of staff. In this paper, a novel cutting pattern identification method through the cutting acoustic signal of the shearer is proposed. The signal is clustering by fuzzy C-means (FCM and a hybrid optimization algorithm, combining the fruit fly and genetic optimization algorithm (FGOA. Firstly, an industrial microphone is installed on the shearer and the acoustic signal is collected as the source signal due to its obvious advantages of compact size, non-contact measurement and ease of remote transmission. The original sound is decomposed by multi-resolution wavelet packet transform (WPT, and the normalized energy of each node is extracted as a feature vector. Then, FGOA, by introducing a genetic proportion coefficient into the basic fruit fly optimization algorithm (FOA, is applied to overcome the disadvantages of being time-consuming and sensitivity to initial centroids of the traditional FCM. A simulation example, with the accuracy of 95%, and some comparisons prove the effectiveness and superiority of the proposed scheme. Finally, an industrial test validates the practical effect.

  7. Combined Effect of Nutrient and Pest Managements on Substrate Utilization Pattern of Soil Microbial Population in Hybrid Rice Cropping System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A field experiment was conducted to study the combined effect of nutrient and pest managements on soil biomass phospholipid contents, functional biodiversity and substrate utilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N, P and K fertilizers (as urea, calcium superphosphate and KCl respectively) were incorporated at 100, 25, and 100 kg ha-1, respectively, and the various pesticides were applied at the recommended rates. The results of the experiment demonstrated a decline in the microbial abundance and soil microbial biomass phospholipid contents with the advancement of crop growth, and significant changes in substrate utilization pattern of soil microbial population studied were observed with different management practices and at different growth stages. The principal component analysis (PGA) using all 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicating that they have different patterns of carbon utilization under different habitats. The data showed that diversity in microbial community continuously changed with the progression in crop stage, particularly at physiological maturity (PM) stage that was evident from the utilization of different carbon sources at various crop stages.

  8. A Dynamic Control Strategy for Hybrid Electric Vehicles Based on Parameter Optimization for Multiple Driving Cycles and Driving Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Zhenzhen Lei

    2017-01-01

    Full Text Available The driving pattern has an important influence on the parameter optimization of the energy management strategy (EMS for hybrid electric vehicles (HEVs. A new algorithm using simulated annealing particle swarm optimization (SA-PSO is proposed for parameter optimization of both the power system and control strategy of HEVs based on multiple driving cycles in order to realize the minimum fuel consumption without impairing the dynamic performance. Furthermore, taking the unknown of the actual driving cycle into consideration, an optimization method of the dynamic EMS based on driving pattern recognition is proposed in this paper. The simulation verifications for the optimized EMS based on multiple driving cycles and driving pattern recognition are carried out using Matlab/Simulink platform. The results show that compared with the original EMS, the former strategy reduces the fuel consumption by 4.36% and the latter one reduces the fuel consumption by 11.68%. A road test on the prototype vehicle is conducted and the effectiveness of the proposed EMS is validated by the test data.

  9. Genomic insights into hybridization in a localized region of sympatr y between pewee sister species (Contopus sordidulus × C. virens) and their chromosomal patterns of differentiation

    Institute of Scientific and Technical Information of China (English)

    Joseph D Manthey; and Mark B Robbins

    2016-01-01

    Background: The Great Plains of the United States includes a large number of hybrid and contact zones between bird species. The amount of gene lfow between sister species in these zones ranges from very rare hybridization events to widespread and prevalent introgression. Some of these avian systems have been studied extensively, while others have been indeterminate of whether hybridization exists in areas of sympatry. Using genomic-level approaches allows investigation of genomic patterns of hybridization and gene lfow between species—or lack thereof. Methods: We investigated a narrow zone of sympatry in Nebraska, USA between pewee species (Contopus sordidu-lus and C. virens), for which no hybridization has been conifrmed. We used thousands of single nucleotide polymor-phisms to identify potential hybridization and investigate genomic patterns of differentiation between these two species. Results: We found evidence of multiple hybrid individuals in the contact zone. Little genomic variation was ifxed between species, but a large proportion had differentiated allele frequencies between species. There was a positive relationship between genetic differentiation and chromosome size. Conclusions: We provided the ifrst conclusive evidence of hybridization between C. sordidulus and C. virens, in a region where secondary contact likely occurred due to human disturbance and habitat modiifcation. The genomic patterns of differentiation affrm that these species split in the relatively recent past. Finally, the relationship of chro-mosome size and genetic differentiation may have resulted from differential rates of chromosomal recombination in songbirds and genetic differentiation between species largely due to genetic drift (possibly in concert with selection).

  10. Heavy metal incorporated helium ion active hybrid non-chemically amplified resists: Nano-patterning with low line edge roughness

    Science.gov (United States)

    Reddy, Pulikanti Guruprasad; Thakur, Neha; Lee, Chien-Lin; Chien, Sheng-Wei; Pradeep, Chullikkattil P.; Ghosh, Subrata; Tsai, Kuen-Yu; Gonsalves, Kenneth E.

    2017-08-01

    Helium (He) ion lithography is being considered as one of the most promising and emerging technology for the manufacturing of next generation integrated circuits (ICs) at nanolevel. However, He-ion active resists are rarely reported. In this context, we are introducing a new non-chemically amplified hybrid resist (n-CAR), MAPDSA-MAPDST, for high resolution He-ion beam lithography (HBL) applications. In the resist architecture, 2.15 % antimony is incorporated as heavy metal in the form of antimonate. This newly developed resists has successfully used for patterning 20 nm negative tone features at a dose of 60 μC/cm2. The resist offered very low line edge roughness (1.27±0.31 nm) for 20 nm line features. To our knowledge, this is the first He-ion active hybrid resist for nanopatterning. The contrast (γ) and sensitivity (E0) of this resist were calculated from the contrast curve as 0.73 and 7.2 μC/cm2, respectively.

  11. Heavy metal incorporated helium ion active hybrid non-chemically amplified resists: Nano-patterning with low line edge roughness

    Directory of Open Access Journals (Sweden)

    Pulikanti Guruprasad Reddy

    2017-08-01

    Full Text Available Helium (He ion lithography is being considered as one of the most promising and emerging technology for the manufacturing of next generation integrated circuits (ICs at nanolevel. However, He-ion active resists are rarely reported. In this context, we are introducing a new non-chemically amplified hybrid resist (n-CAR, MAPDSA-MAPDST, for high resolution He-ion beam lithography (HBL applications. In the resist architecture, 2.15 % antimony is incorporated as heavy metal in the form of antimonate. This newly developed resists has successfully used for patterning 20 nm negative tone features at a dose of 60 μC/cm2. The resist offered very low line edge roughness (1.27±0.31 nm for 20 nm line features. To our knowledge, this is the first He-ion active hybrid resist for nanopatterning. The contrast (γ and sensitivity (E0 of this resist were calculated from the contrast curve as 0.73 and 7.2 μC/cm2, respectively.

  12. Introgression of wing pattern alleles and speciation via homoploid hybridization in Heliconius butterflies: a review of evidence from the genome.

    Science.gov (United States)

    Brower, Andrew V Z

    2013-02-01

    The diverse Müllerian mimetic wing patterns of neotropical Heliconius (Nymphalidae) have been proposed to be not only aposematic signals to potential predators, but also intra- and interspecific recognition signals that allow the butterflies to maintain their specific identities, and which perhaps drive the process of speciation, as well. Adaptive features under differential selection that also serve as cues for assortative mating have been referred to as 'magic traits', which can drive ecological speciation. Such traits are expected to exhibit allelic differentiation between closely related species with ongoing gene flow, whereas unlinked neutral traits are expected to be homogenized to a greater degree by introgression. However, recent evidence suggests that interspecific hybridization among Heliconius butterflies may have resulted in adaptive introgression of these very same traits across species boundaries, and in the evolution of new species by homoploid hybrid speciation. The theory and data supporting various aspects of the apparent paradox of 'magic trait' introgression are reviewed, with emphasis on population genomic comparisons of Heliconius melpomene and its close relatives.

  13. 3-D shape measurement by composite pattern projection and hybrid processing.

    Science.gov (United States)

    Chen, H J; Zhang, J; Lv, D J; Fang, J

    2007-09-17

    This article presents a projection system with a novel composite pattern for one-shot acquisition of 3D surface shape. The pattern is composed of color encoded stripes and cosinoidal intensity fringes, with parallel arrangement. The stripe edges offer absolute height phases with high accuracy, and the cosinoidal fringes provide abundant relative phases involved in the intensity distribution. Wavelet transform is utilized to obtain the relative phase distribution of the fringe pattern, and the absolute height phases measured by triangulation are combined to calibrate the phase data in unwrapping, so as to eliminate the initial and noise errors and to reduce the accumulation and approximation errors. Numerical simulations are performed to prove the new unwrapping algorithms and actual experiments are carried out to show the validity of the proposed technique for accurate 3- D shape measurement.

  14. Design Patterns for Sparse-Matrix Computations on Hybrid CPU/GPU Platforms

    Directory of Open Access Journals (Sweden)

    Valeria Cardellini

    2014-01-01

    Full Text Available We apply object-oriented software design patterns to develop code for scientific software involving sparse matrices. Design patterns arise when multiple independent developments produce similar designs which converge onto a generic solution. We demonstrate how to use design patterns to implement an interface for sparse matrix computations on NVIDIA GPUs starting from PSBLAS, an existing sparse matrix library, and from existing sets of GPU kernels for sparse matrices. We also compare the throughput of the PSBLAS sparse matrix–vector multiplication on two platforms exploiting the GPU with that obtained by a CPU-only PSBLAS implementation. Our experiments exhibit encouraging results regarding the comparison between CPU and GPU executions in double precision, obtaining a speedup of up to 35.35 on NVIDIA GTX 285 with respect to AMD Athlon 7750, and up to 10.15 on NVIDIA Tesla C2050 with respect to Intel Xeon X5650.

  15. Hybrid copper complex-derived conductive patterns printed on polyimide substrates

    Science.gov (United States)

    Lee, Byoungyoon; Jeong, Sooncheol; Kim, Yoonhyun; Jeong, Inbum; Woo, Kyoohee; Moon, Jooho

    2012-06-01

    We synthesized new copper complexes that can be readily converted into highly conductive Cu film. Mechanochemical milling of copper (I) oxide suspended in formic acid resulted in the submicron-sized Cu formate together Cu nanoparticles. The submicrometer-sized Cu formates are reactive toward inter-particle sintering and metallic Cu seeds present in the Cu complexes assist their decomposition and the nucleation of Cu. The hybrid copper complex film printed on polyimide substrate is decomposed into dense and uniform Cu layer after annealing at 250 °C for 30 min under nitrogen atmosphere. The resulting Cu film exhibited a low resistivity of 8.2 μΩ·cm and good adhesion characteristics.

  16. Dependence of the productivity of maize and soybean intercropping systems on hybrid type and plant arrangement pattern

    Directory of Open Access Journals (Sweden)

    Dolijanović Željko

    2013-01-01

    Full Text Available Intercropping systems could improve utilization of the most important resources (soil, water and nutrients, provide a better control of weeds, pests and diseases, and finally higher productivity, especially under rain-fed growing conditions. This study aimed to determine the effects of three maize (Zea mays L. prolific hybrids (FAO 500, 600 and 700 and the spatial intercrop patterns on the above-ground biomass and grain yields of maize and soybean (Glycine max L. Merrill, on chernozem soil type at Zemun Polje, Belgrade, in 2003, 2004 and 2005. The experimental design was a complete randomized block with four replications and three treatments: 3 rows of maize and 3 rows of soybean in strips for each maize hybrid (three variants, 3 rows of maize and 3 rows of soybean in alternate rows for each hybrid (another three variants and monocrops of both maize and soybeans. To optimize the ecological and economic benefits of maize/soybean intercrop in terms of yield, variety selection and compatibility of the component crops should be made using established agronomic management practices involving the two crops. Suitable maize varieties for maize/soybean intercrop systems are varieties that have less dense canopy. These varieties would therefore have lesser shading effect to the understory beans. However, establishment of an appropriate spatial arrangement of the component crops would be essential to alleviate negative effects especially on the less competitive crop. The intercropping system in alternate rows showed significantly higher above-ground biomass and grain yields in comparation with both the strip intercropping system and maize monocrops in 2004. Soybean gave significantly lower above-ground biomass and grain yield in intercrops than in monocrops. Maize prolific hybrid growing in intercropping with soybean as legume crop, increased productivity of cropping system, especially in favourable agroecological conditions. Maize and soybean yields

  17. Cellular nanoscale sensory wave computing

    CERN Document Server

    Baatar, Chagaan; Roska, Tamas

    2010-01-01

    This fresh perspective of sensory computing successfully bridges the gap between nanoscale devices and CMOS integrated circuits. Practical and complex algorithms are also discussed, in addition to new developments like the nanoscale antenna.

  18. Using Protein Dimers to Maximize the Protein Hybridization Efficiency with Multisite DNA Origami Scaffolds.

    Science.gov (United States)

    Verma, Vikash; Mallik, Leena; Hariadi, Rizal F; Sivaramakrishnan, Sivaraj; Skiniotis, Georgios; Joglekar, Ajit P

    2015-01-01

    DNA origami provides a versatile platform for conducting 'architecture-function' analysis to determine how the nanoscale organization of multiple copies of a protein component within a multi-protein machine affects its overall function. Such analysis requires that the copy number of protein molecules bound to the origami scaffold exactly matches the desired number, and that it is uniform over an entire scaffold population. This requirement is challenging to satisfy for origami scaffolds with many protein hybridization sites, because it requires the successful completion of multiple, independent hybridization reactions. Here, we show that a cleavable dimerization domain on the hybridizing protein can be used to multiplex hybridization reactions on an origami scaffold. This strategy yields nearly 100% hybridization efficiency on a 6-site scaffold even when using low protein concentration and short incubation time. It can also be developed further to enable reliable patterning of a large number of molecules on DNA origami for architecture-function analysis.

  19. Using Protein Dimers to Maximize the Protein Hybridization Efficiency with Multisite DNA Origami Scaffolds.

    Directory of Open Access Journals (Sweden)

    Vikash Verma

    Full Text Available DNA origami provides a versatile platform for conducting 'architecture-function' analysis to determine how the nanoscale organization of multiple copies of a protein component within a multi-protein machine affects its overall function. Such analysis requires that the copy number of protein molecules bound to the origami scaffold exactly matches the desired number, and that it is uniform over an entire scaffold population. This requirement is challenging to satisfy for origami scaffolds with many protein hybridization sites, because it requires the successful completion of multiple, independent hybridization reactions. Here, we show that a cleavable dimerization domain on the hybridizing protein can be used to multiplex hybridization reactions on an origami scaffold. This strategy yields nearly 100% hybridization efficiency on a 6-site scaffold even when using low protein concentration and short incubation time. It can also be developed further to enable reliable patterning of a large number of molecules on DNA origami for architecture-function analysis.

  20. Using Protein Dimers to Maximize the Protein Hybridization Efficiency with Multisite DNA Origami Scaffolds

    Science.gov (United States)

    Verma, Vikash; Mallik, Leena; Hariadi, Rizal F.; Sivaramakrishnan, Sivaraj; Skiniotis, Georgios; Joglekar, Ajit P.

    2015-01-01

    DNA origami provides a versatile platform for conducting ‘architecture-function’ analysis to determine how the nanoscale organization of multiple copies of a protein component within a multi-protein machine affects its overall function. Such analysis requires that the copy number of protein molecules bound to the origami scaffold exactly matches the desired number, and that it is uniform over an entire scaffold population. This requirement is challenging to satisfy for origami scaffolds with many protein hybridization sites, because it requires the successful completion of multiple, independent hybridization reactions. Here, we show that a cleavable dimerization domain on the hybridizing protein can be used to multiplex hybridization reactions on an origami scaffold. This strategy yields nearly 100% hybridization efficiency on a 6-site scaffold even when using low protein concentration and short incubation time. It can also be developed further to enable reliable patterning of a large number of molecules on DNA origami for architecture-function analysis. PMID:26348722

  1. A multi-pattern hash-binary hybrid algorithm for URL matching in the HTTP protocol.

    Science.gov (United States)

    Zeng, Ping; Tan, Qingping; Meng, Xiankai; Shao, Zeming; Xie, Qinzheng; Yan, Ying; Cao, Wei; Xu, Jianjun

    2017-01-01

    In this paper, based on our previous multi-pattern uniform resource locator (URL) binary-matching algorithm called HEM, we propose an improved multi-pattern matching algorithm called MH that is based on hash tables and binary tables. The MH algorithm can be applied to the fields of network security, data analysis, load balancing, cloud robotic communications, and so on-all of which require string matching from a fixed starting position. Our approach effectively solves the performance problems of the classical multi-pattern matching algorithms. This paper explores ways to improve string matching performance under the HTTP protocol by using a hash method combined with a binary method that transforms the symbol-space matching problem into a digital-space numerical-size comparison and hashing problem. The MH approach has a fast matching speed, requires little memory, performs better than both the classical algorithms and HEM for matching fields in an HTTP stream, and it has great promise for use in real-world applications.

  2. Knitting the catalytic pattern of artificial photosynthesis to a hybrid graphene nanotexture.

    Science.gov (United States)

    Quintana, Mildred; López, Alejandro Montellano; Rapino, Stefania; Toma, Francesca Maria; Iurlo, Matteo; Carraro, Mauro; Sartorel, Andrea; Maccato, Chiara; Ke, Xiaoxing; Bittencourt, Carla; Da Ros, Tatiana; Van Tendeloo, Gustaaf; Marcaccio, Massimo; Paolucci, Francesco; Prato, Maurizio; Bonchio, Marcella

    2013-01-22

    The artificial leaf project calls for new materials enabling multielectron catalysis with minimal overpotential, high turnover frequency, and long-term stability. Is graphene a better material than carbon nanotubes to enhance water oxidation catalysis for energy applications? Here we show that functionalized graphene with a tailored distribution of polycationic, quaternized, ammonium pendants provides an sp(2) carbon nanoplatform to anchor a totally inorganic tetraruthenate catalyst, mimicking the oxygen evolving center of natural PSII. The resulting hybrid material displays oxygen evolution at overpotential as low as 300 mV at neutral pH with negligible loss of performance after 4 h testing. This multilayer electroactive asset enhances the turnover frequency by 1 order of magnitude with respect to the isolated catalyst, and provides a definite up-grade of the carbon nanotube material, with a similar surface functionalization. Our innovation is based on a noninvasive, synthetic protocol for graphene functionalization that goes beyond the ill-defined oxidation-reduction methods, allowing a definite control of the surface properties.

  3. Multi-Input Single Output SSSC based damping controller design by a hybrid Improved Differential Evolution-Pattern Search approach.

    Science.gov (United States)

    Panda, Sidhartha; Yegireddy, Narendra Kumar

    2015-09-01

    In this paper, a hybrid Improved Differential Evolution and Pattern Search (hIDEPS) approach is proposed for the design of a PI-Type Multi-Input Single Output (MISO) Static Synchronous Series Compensator (SSSC) based damping controller. The improvement in Differential Evolution (DE) algorithm is introduced by a simple but effective scheme of changing two of its most important control parameters i.e. step size and crossover probability with an objective of achieving improved performance. Pattern Search (PS) is subsequently employed to fine tune the best solution provided by modified DE algorithm. The superiority of a proposed hIDEPS technique over DE and improved DE has also been demonstrated. At the outset, this concept is applied to a SSSC connected in a Single Machine Infinite Bus (SMIB) power system and then extended to a multi-machine power system. To show the effectiveness and robustness of the proposed design approach, simulation results are presented and compared with DE and Particle Swarm Optimization (PSO) optimized Single Input Single Output (SISO) SSSC based damping controllers. It is observed that the proposed approach yield superior damping performance compared to some approaches available in the literature.

  4. Interfaces in nanoscale photovoltaics

    NARCIS (Netherlands)

    Öner, S.Z.

    2016-01-01

    This thesis deals with material interfaces in nanoscale photovoltaics. Interface properties between the absorbing semiconductor and other employed materials are crucial for an efficient solar cell. While the optical properties are largely unaffected by a few nanometer thin layer, the electronic prop

  5. Interfaces in nanoscale photovoltaics

    NARCIS (Netherlands)

    Öner, S.Z.

    2016-01-01

    This thesis deals with material interfaces in nanoscale photovoltaics. Interface properties between the absorbing semiconductor and other employed materials are crucial for an efficient solar cell. While the optical properties are largely unaffected by a few nanometer thin layer, the electronic prop

  6. NANOSCALE PROCESS ENGINEERING

    Institute of Scientific and Technical Information of China (English)

    Qixiang Wang; Fei Wei

    2003-01-01

    The research of nanoscale process engineering (NPE) is based on the interdisciplinary nature of nanoscale science and technology. It mainly deals with transformation of materials and energy into nanostructured materials and nanodevices, and synergizes the multidisciplinary convergence between materials science and technology, biotechnology, and information technology. The core technologies of NPE concern all aspects of nanodevice construction and operation, such as manufacture of nanomaterials "by design", concepts and design of nanoarchitectures, and manufacture and control of customizable nanodevices. Two main targets of NPE at present are focused on nanoscale manufacture and concept design of nanodevices. The research progress of nanoscale manufacturing processes focused on creating nanostructures and assembling them into nanosystems and larger scale architectures has built the interdiscipline of NPE. The concepts and design of smart, multi-functional, environmentally compatible and customizable nanodevice prototypes built from the nanostructured systems of nanocrystalline, nanoporous and microemulsion systems are most challenging tasks of NPE. The development of NPE may also impel us to consider the curriculum and educational reform of chemical engineering in universities.

  7. Effects of land policy on hybrid rural-urban development patterns and resilience: A case study of the territorial development in the Bangkok Metropolitan Region

    NARCIS (Netherlands)

    Rongwinriyaphanich, S.

    2012-01-01

    This article aims to provide planners and policy makers with a better understanding about potential impacts of land policy on the shaping of hybrid rural-urban development patterns and their effects on resilience enhancement of urban systems. It examines the impacts of diverse development policies a

  8. Direct fabrication of nanoscale bio-adhesive patterns by electron beam surface modification of plasma polymerized poly ethylene oxide-like coatings.

    Science.gov (United States)

    Brétagnol, Frédéric; Sirghi, Lucel; Mornet, Stéphane; Sasaki, Takao; Gilliland, Douglas; Colpo, Pascal; Rossi, Francois

    2008-03-26

    In this study we present a method to produce nanostructured surfaces containing bio-adhesive features inside a non bio-adhesive matrix. The strategy is based on the combination of low pressure plasma polymerization and electron beam lithography processes and allows the fabrication of the structured materials in just two steps without using any solvents. In a first step, a thin protein-and-cell-repelling coating (∼10 nm) is obtained by plasma polymerization of Di-glyme. Then, in a second step, the bio-adhesive properties of the layer are tuned by monitoring the concentration of ether bonds of the film by irradiating it locally by different irradiation doses with an electron beam. Time-of-flight secondary ion mass spectroscopy and atomic force microscopy analysis have been used to characterize the produced surfaces. Experiments with a model protein (bovine serum albumin) on the patterned surfaces show preferential adhesion to the irradiated regions, indicating the potential of this simple technique for the development of highly compacted sensitive bio-sensing devices.

  9. Nanoscale Surface Modification of Layered Materials

    Science.gov (United States)

    O'Shea, Aaron

    2011-11-01

    A scanning electron microscope can magnify a sample many times greater than a standard microscope, down to nanoscale dimensions. It can also be used to form patterns on the surfaces of certain materials, a technique used to create microchips. We have developed a technique that simplifies and expedites this process using an unmodified scanning electron microscope. Using this technique, we are able to alter the surface chemistry in a controlled pattern on a special class of materials called transition metal dichalcogenides. These materials have many useful applications: industrial lubricants; high strength nanocomposites; advanced solar cells; and next generation electronics. Altering the surface chemistry of these materials at the nanoscale results in unusual quantum behavior, which is useful in nanotechnology.

  10. The Role of Interaction Patterns with Hybrid Electric Vehicle Eco-Features for Drivers' Eco-Driving Performance.

    Science.gov (United States)

    Arend, Matthias G; Franke, Thomas

    2017-03-01

    The objective of the present research was to understand drivers' interaction patterns with hybrid electric vehicles' (HEV) eco-features (electric propulsion, regenerative braking, neutral mode) and their relationship to fuel efficiency and driver characteristics (technical system knowledge, eco-driving motivation). Eco-driving (driving behaviors performed to achieve higher fuel efficiency) has the potential to reduce CO2 emissions caused by road vehicles. Eco-driving in HEVs is particularly challenging due to the systems' dynamic energy flows. As a result, drivers are likely to show diverse eco-driving behaviors, depending on factors like knowledge and motivation. The eco-features represent an interface for the control of the systems' energy flows. A sample of 121 HEV drivers who had constantly logged their fuel consumption prior to the study participated in an online questionnaire. Drivers' interaction patterns with the eco-features were related to fuel efficiency. A common factor was identified in an exploratory factor analysis, characterizing the intensity of actively dealing with electric energy, which was also related to fuel efficiency. Driver characteristics were not related to this factor, yet they were significant predictors of fuel efficiency. From the perspective of user-energy interaction, the relationship of the aggregated factor to fuel efficiency emphasizes the central role of drivers' perception of and interaction with energy conversions in determining HEV eco-driving success. To arrive at an in-depth understanding of drivers' eco-driving behaviors that can guide interface design, authors of future research should be concerned with the psychological processes that underlie drivers' interaction patterns with eco-features.

  11. Patterns of Limnohabitans microdiversity across a large set of freshwater habitats as revealed by Reverse Line Blot Hybridization.

    Directory of Open Access Journals (Sweden)

    Jan Jezbera

    Full Text Available Among abundant freshwater Betaproteobacteria, only few groups are considered to be of central ecological importance. One of them is the well-studied genus Limnohabitans and mainly its R-BT subcluster, investigated previously mainly by fluorescence in situ hybridization methods. We designed, based on sequences from a large Limnohabitans culture collection, 18 RLBH (Reverse Line Blot Hybridization probes specific for different groups within the genus Limnohabitans by targeting diagnostic sequences on their 16 S-23 S rRNA ITS regions. The developed probes covered in sum 92% of the available isolates. This set of probes was applied to environmental DNA originating from 161 different European standing freshwater habitats to reveal the microdiversity (intra-genus patterns of the Limnohabitans genus along a pH gradient. Investigated habitats differed in various physicochemical parameters, and represented a very broad range of standing freshwater habitats. The Limnohabitans microdiversity, assessed as number of RLBH-defined groups detected, increased significantly along the gradient of rising pH of habitats. 14 out of 18 probes returned detection signals that allowed predictions on the distribution of distinct Limnohabitans groups. Most probe-defined Limnohabitans groups showed preferences for alkaline habitats, one for acidic, and some seemed to lack preferences. Complete niche-separation was indicated for some of the probe-targeted groups. Moreover, bimodal distributions observed for some groups of Limnohabitans, suggested further niche separation between genotypes within the same probe-defined group. Statistical analyses suggested that different environmental parameters such as pH, conductivity, oxygen and altitude influenced the distribution of distinct groups. The results of our study do not support the hypothesis that the wide ecological distribution of Limnohabitans bacteria in standing freshwater habitats results from generalist adaptations of

  12. A Hybrid One-Way ANOVA Approach for the Robust and Efficient Estimation of Differential Gene Expression with Multiple Patterns.

    Directory of Open Access Journals (Sweden)

    Mohammad Manir Hossain Mollah

    Full Text Available Identifying genes that are differentially expressed (DE between two or more conditions with multiple patterns of expression is one of the primary objectives of gene expression data analysis. Several statistical approaches, including one-way analysis of variance (ANOVA, are used to identify DE genes. However, most of these methods provide misleading results for two or more conditions with multiple patterns of expression in the presence of outlying genes. In this paper, an attempt is made to develop a hybrid one-way ANOVA approach that unifies the robustness and efficiency of estimation using the minimum β-divergence method to overcome some problems that arise in the existing robust methods for both small- and large-sample cases with multiple patterns of expression.The proposed method relies on a β-weight function, which produces values between 0 and 1. The β-weight function with β = 0.2 is used as a measure of outlier detection. It assigns smaller weights (≥ 0 to outlying expressions and larger weights (≤ 1 to typical expressions. The distribution of the β-weights is used to calculate the cut-off point, which is compared to the observed β-weight of an expression to determine whether that gene expression is an outlier. This weight function plays a key role in unifying the robustness and efficiency of estimation in one-way ANOVA.Analyses of simulated gene expression profiles revealed that all eight methods (ANOVA, SAM, LIMMA, EBarrays, eLNN, KW, robust BetaEB and proposed perform almost identically for m = 2 conditions in the absence of outliers. However, the robust BetaEB method and the proposed method exhibited considerably better performance than the other six methods in the presence of outliers. In this case, the BetaEB method exhibited slightly better performance than the proposed method for the small-sample cases, but the the proposed method exhibited much better performance than the BetaEB method for both the small- and large

  13. An interspecific fungal hybrid reveals cross-kingdom rules for allopolyploid gene expression patterns.

    Directory of Open Access Journals (Sweden)

    Murray P Cox

    2014-03-01

    Full Text Available Polyploidy, a state in which the chromosome complement has undergone an increase, is a major force in evolution. Understanding the consequences of polyploidy has received much attention, and allopolyploids, which result from the union of two different parental genomes, are of particular interest because they must overcome a suite of biological responses to this merger, known as "genome shock." A key question is what happens to gene expression of the two gene copies following allopolyploidization, but until recently the tools to answer this question on a genome-wide basis were lacking. Here we utilize high throughput transcriptome sequencing to produce the first genome-wide picture of gene expression response to allopolyploidy in fungi. A novel pipeline for assigning sequence reads to the gene copies was used to quantify their expression in a fungal allopolyploid. We find that the transcriptional response to allopolyploidy is predominantly conservative: both copies of most genes are retained; over half the genes inherit parental gene expression patterns; and parental differential expression is often lost in the allopolyploid. Strikingly, the patterns of gene expression change are highly concordant with the genome-wide expression results of a cotton allopolyploid. The very different nature of these two allopolyploids implies a conserved, eukaryote-wide transcriptional response to genome merger. We provide evidence that the transcriptional responses we observe are mostly driven by intrinsic differences between the regulatory systems in the parent species, and from this propose a mechanistic model in which the cross-kingdom conservation in transcriptional response reflects conservation of the mutational processes underlying eukaryotic gene regulatory evolution. This work provides a platform to develop a universal understanding of gene expression response to allopolyploidy and suggests that allopolyploids are an exceptional system to investigate gene

  14. Nanoscale device architectures derived from biological assemblies: The case of tobacco mosaic virus and (apo)ferritin

    Science.gov (United States)

    Calò, Annalisa; Eiben, Sabine; Okuda, Mitsuhiro; Bittner, Alexander M.

    2016-03-01

    Virus particles and proteins are excellent examples of naturally occurring structures with well-defined nanoscale architectures, for example, cages and tubes. These structures can be employed in a bottom-up assembly strategy to fabricate repetitive patterns of hybrid organic-inorganic materials. In this paper, we review methods of assembly that make use of protein and virus scaffolds to fabricate patterned nanostructures with very high spatial control. We chose (apo)ferritin and tobacco mosaic virus (TMV) as model examples that have already been applied successfully in nanobiotechnology. Their interior space and their exterior surfaces can be mineralized with inorganic layers or nanoparticles. Furthermore, their native assembly abilities can be exploited to generate periodic architectures for integration in electrical and magnetic devices. We introduce the state of the art and describe recent advances in biomineralization techniques, patterning and device production with (apo)ferritin and TMV.

  15. Sensing at the nanoscale

    Science.gov (United States)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    The merits of nanostructures in sensing may seem obvious, yet playing these attributes to their maximum advantage can be a work of genius. As fast as sensing technology is improving, expectations are growing, with demands for cheaper devices with higher sensitivities and an ever increasing range of functionalities and compatibilities. At the same time tough scientific challenges like low power operation, noise and low selectivity are keeping researchers busy. This special issue on sensing at the nanoscale with guest editor Christofer Hierold from ETH Zurich features some of the latest developments in sensing research pushing at the limits of current capabilities. Cheap and easy fabrication is a top priority. Among the most popular nanomaterials in sensing are ZnO nanowires and in this issue Dario Zappa and colleagues at Brescia University in Italy simplify an already cheap and efficient synthesis method, demonstrating ZnO nanowire fabrication directly onto silicon substrates [1]. Meanwhile Nicolae Barson and colleagues in Germany point out the advantages of flame spray pyrolysis fabrication in a topical review [2] and, maximizing on existing resources, researchers in Denmark and Taiwan report cantilever sensing using a US20 commercial DVD-ROM optical pickup unit as the readout source [3]. The sensor is designed to detect physiological concentrations of soluble urokinase plasminogen activator receptor, a protein associated with inflammation due to HIV, cancer and other infectious diseases. With their extreme properties carbon nanostructures feature prominently in the issue, including the demonstration of a versatile and flexible carbon nanotube strain sensor [4] and a graphene charge sensor with sensitivities of the order of 1.3 × 10-3 e Hz-1/2 [5]. The issue of patterning for sensing devices is also tackled by researchers in the US who demonstrate a novel approach for multicomponent pattering metal/metal oxide nanoparticles on graphene [6]. Changes in electrical

  16. Preface: Charge transport in nanoscale junctions

    Science.gov (United States)

    Albrecht, Tim; Kornyshev, Alexei; Bjørnholm, Thomas

    2008-09-01

    the molecular level. Nanoscale charge transport experiments in ionic liquids extend the field to high temperatures and to systems with intriguing interfacial potential distributions. Other directions may include dye-sensitized solar cells, new sensor applications and diagnostic tools for the study of surface-bound single molecules. Another motivation for this special issue is thus to highlight activities across different research communities with nanoscale charge transport as a common denominator. This special issue gathers 27 articles by scientists from the United States, Germany, the UK, Denmark, Russia, France, Israel, Canada, Australia, Sweden, Switzerland, the Netherlands, Belgium and Singapore; it gives us a flavour of the current state-of-the-art of this diverse research area. While based on contributions from many renowned groups and institutions, it obviously cannot claim to represent all groups active in this very broad area. Moreover, a number of world-leading groups were unable to take part in this project within the allocated time limit. Nevertheless, we regard the current selection of papers to be representative enough for the reader to draw their own conclusions about the current status of the field. Each paper is original and has its own merit, as all papers in Journal of Physics: Condensed Matter special issues are subjected to the same scrutiny as regular contributions. The Guest Editors have deliberately not defined the specific subjects covered in this issue. These came out logically from the development of this area, for example: 'Traditional' solid state nanojunctions based on adsorbed layers, oxide films or nanowires sandwiched between two electrodes: effects of molecular structure (aromaticity, anchoring groups), symmetry, orientation, dynamics (noise patterns) and current-induced heating. Various 'physical effects': inelastic tunnelling and Coulomb blockade, polaron effects, switching modes, and negative differential resistance; the role of

  17. Surface nanoscale axial photonics

    CERN Document Server

    Sumetsky, M

    2011-01-01

    Dense photonic integration promises to revolutionize optical computing and communications. However, efforts towards this goal face unacceptable attenuation of light caused by surface roughness in microscopic devices. Here we address this problem by introducing Surface Nanoscale Axial Photonics (SNAP). The SNAP platform is based on whispering gallery modes circulating around the optical fiber surface and undergoing slow axial propagation readily described by the one-dimensional Schr\\"odinger equation. These modes can be steered with dramatically small nanoscale variation of the fiber radius, which is quite simple to introduce in practice. The extremely low loss of SNAP devices is achieved due to the fantastically low surface roughness inherent in a drawn fiber surface. In excellent agreement with the developed theory, we experimentally demonstrate localization of light in quantum wells, halting light by a point source, tunneling through potential barriers, dark states, etc. This demonstration, prototyping basi...

  18. Ellipsometry at the nanoscale

    CERN Document Server

    Hingerl, Kurt

    2013-01-01

    This book presents and introduces ellipsometry in nanoscience and nanotechnology making a bridge between the classical and nanoscale optical behaviour of materials. It delineates the role of the non-destructive and non-invasive optical diagnostics of ellipsometry in improving science and technology of nanomaterials and related processes by illustrating its exploitation, ranging from fundamental studies of the physics and chemistry of nanostructures to the ultimate goal of turnkey manufacturing control. This book is written for a broad readership: materials scientists, researchers, engineers, as well as students and nanotechnology operators who want to deepen their knowledge about both basics and applications of ellipsometry to nanoscale phenomena. It starts as a general introduction for people curious to enter the fields of ellipsometry and polarimetry applied to nanomaterials and progresses to articles by experts on specific fields that span from plasmonics, optics, to semiconductors and flexible electronics...

  19. Electroanalysis at the nanoscale.

    Science.gov (United States)

    Dawson, Karen; O'Riordan, Alan

    2014-01-01

    This article reviews the state of the art of silicon chip-based nanoelectrochemical devices for sensing applications. We first describe analyte mass transport to nanoscale electrodes and emphasize understanding the importance of mass transport for the design of nanoelectrode arrays. We then describe bottom-up and top-down approaches to nanoelectrode fabrication and integration at silicon substrates. Finally, we explore recent examples of on-chip nanoelectrodes employed as sensors and diagnostics, finishing with a brief look at future applications.

  20. Nanoscale imaging of RNA with expansion microscopy.

    Science.gov (United States)

    Chen, Fei; Wassie, Asmamaw T; Cote, Allison J; Sinha, Anubhav; Alon, Shahar; Asano, Shoh; Daugharthy, Evan R; Chang, Jae-Byum; Marblestone, Adam; Church, George M; Raj, Arjun; Boyden, Edward S

    2016-08-01

    The ability to image RNA identity and location with nanoscale precision in intact tissues is of great interest for defining cell types and states in normal and pathological biological settings. Here, we present a strategy for expansion microscopy of RNA. We developed a small-molecule linker that enables RNA to be covalently attached to a swellable polyelectrolyte gel synthesized throughout a biological specimen. Then, postexpansion, fluorescent in situ hybridization (FISH) imaging of RNA can be performed with high yield and specificity as well as single-molecule precision in both cultured cells and intact brain tissue. Expansion FISH (ExFISH) separates RNAs and supports amplification of single-molecule signals (i.e., via hybridization chain reaction) as well as multiplexed RNA FISH readout. ExFISH thus enables super-resolution imaging of RNA structure and location with diffraction-limited microscopes in thick specimens, such as intact brain tissue and other tissues of importance to biology and medicine.

  1. Soft lithography for micro- and nanoscale patterning.

    Science.gov (United States)

    Qin, Dong; Xia, Younan; Whitesides, George M

    2010-03-01

    This protocol provides an introduction to soft lithography--a collection of techniques based on printing, molding and embossing with an elastomeric stamp. Soft lithography provides access to three-dimensional and curved structures, tolerates a wide variety of materials, generates well-defined and controllable surface chemistries, and is generally compatible with biological applications. It is also low in cost, experimentally convenient and has emerged as a technology useful for a number of applications that include cell biology, microfluidics, lab-on-a-chip, microelectromechanical systems and flexible electronics/photonics. As examples, here we focus on three of the commonly used soft lithographic techniques: (i) microcontact printing of alkanethiols and proteins on gold-coated and glass substrates; (ii) replica molding for fabrication of microfluidic devices in poly(dimethyl siloxane), and of nanostructures in polyurethane or epoxy; and (iii) solvent-assisted micromolding of nanostructures in poly(methyl methacrylate).

  2. Engineering Nanoscale Biological Molecular Motors

    OpenAIRE

    Korosec, Chapin; Forde, Nancy R.

    2017-01-01

    Understanding the operation of biological molecular motors, nanoscale machines that transduce electrochemical energy into mechanical work, is enhanced by bottom-up strategies to synthesize novel motors.

  3. Complex Phenomena in Nanoscale Systems

    CERN Document Server

    Casati, Giulio

    2009-01-01

    Nanoscale physics has become one of the rapidly developing areas of contemporary physics because of its direct relevance to newly emerging area, nanotechnologies. Nanoscale devices and quantum functional materials are usually constructed based on the results of fundamental studies on nanoscale physics. Therefore studying physical phenomena in nanosized systems is of importance for progressive development of nanotechnologies. In this context study of complex phenomena in such systems and using them for controlling purposes is of great practical importance. Namely, such studies are brought together in this book, which contains 27 papers on various aspects of nanoscale physics and nonlinear dynamics.

  4. Impact of real world driving pattern and all-electric range on battery sizing and cost of plug-in hybrid electric two-wheeler

    Science.gov (United States)

    Amjad, Shaik; Rudramoorthy, R.; Neelakrishnan, S.; Varman, K. Sri Raja; Arjunan, T. V.

    2011-03-01

    This study addresses the impact of an actual drive pattern on the sizing and cost of a battery pack for a plug-in hybrid electric two-wheeler. To estimate the daily average travel distance in fixing the all-electric range of two wheelers, a study conducted in Coimbatore city is presented. A MATLAB simulation model developed for estimating the energy and power requirements in an all-electric strategy using an Indian driving cycle (IDC) and a real-world driving pattern are discussed. The simulation results reveal the impact of the real-world driving pattern on energy consumption and also the influence of all-electric range in sizing the battery pack. To validate the results, a plug-in hybrid electric two-wheeler developed by modifying a standard two-wheeler has been tested on the road with the help of the IDC simulator kit. An annual battery cost comparison shows that nickel-metal-hydride batteries are more economical and suitable for in plug-in hybrid electric two-wheelers.

  5. Gene expression pattern in transmitochondrial cytoplasmic hybrid cells harboring type 2 diabetes-associated mitochondrial DNA haplogroups.

    Directory of Open Access Journals (Sweden)

    Seungwoo Hwang

    Full Text Available Decreased mitochondrial function plays a pivotal role in the pathogenesis of type 2 diabetes mellitus (T2DM. Recently, it was reported that mitochondrial DNA (mtDNA haplogroups confer genetic susceptibility to T2DM in Koreans and Japanese. Particularly, mtDNA haplogroup N9a is associated with a decreased risk of T2DM, whereas haplogroups D5 and F are associated with an increased risk. To examine functional consequences of these haplogroups without being confounded by the heterogeneous nuclear genomic backgrounds of different subjects, we constructed transmitochondrial cytoplasmic hybrid (cybrid cells harboring each of the three haplogroups (N9a, D5, and F in a background of a shared nuclear genome. We compared the functional consequences of the three haplogroups using cell-based assays and gene expression microarrays. Cell-based assays did not detect differences in mitochondrial functions among the haplogroups in terms of ATP generation, reactive oxygen species production, mitochondrial membrane potential, and cellular dehydrogenase activity. However, differential expression and clustering analyses of microarray data revealed that the three haplogroups exhibit a distinctive nuclear gene expression pattern that correlates with their susceptibility to T2DM. Pathway analysis of microarray data identified several differentially regulated metabolic pathways. Notably, compared to the T2DM-resistant haplogroup N9a, the T2DM-susceptible haplogroup F showed down-regulation of oxidative phosphorylation and up-regulation of glycolysis. These results suggest that variations in mtDNA can affect the expression of nuclear genes regulating mitochondrial functions or cellular energetics. Given that impaired mitochondrial function caused by T2DM-associated mtDNA haplogroups is compensated by the nuclear genome, we speculate that defective nuclear compensation, under certain circumstances, might lead to the development of T2DM.

  6. Nanoscale transfer printing for heterogeneous device integration (Conference Presentation)

    Science.gov (United States)

    Hurtado, Antonio; Guilhabert, Benoit J. E.; Strain, Michael J.; Laurand, Nicolas; Jagadish, Chennupati; Dawson, Martin D.

    2017-02-01

    We present a novel nanoscale transfer printing (TP) technology which combines a customized nanolithography system with bespoke elastomeric μ-stamps to controllably pick and place diverse semiconductor structures, e.g. nanowires (NWs), Light Emitting Diodes (LEDs) and thin films, onto targeted locations on heterogeneous material surfaces (e.g. polymers, metals, silica, diamond). Notably, our technique allows the parallel printing of semiconductor structures of different materials onto a large area (of 10cm x 10cm) whilst simultaneously yielding sub-micrometric positioning control (down to below 100nm) and low printing time ( 20s per print step). In the talk, we will present a variety of hybrid integrated devices fabricated with our TP technique. Emphasis will be given to our recent work using Gallium Nitride (GaN) LEDs and Indium Phosphide (InP) NW lasers as building blocks. Using TP protocols, GaN LEDs fabricated from GaN-on-Si have been integrated onto polymer and thin glass surfaces and onto diamond substrates for mechanically flexible optoelectronic devices and effective device heat management respectively. Additionally, ultra-small InP NW lasers ( 5μm long and 500nm diameter) have been integrated onto multiple heterogeneous substrates, including mechanically flexible (polymers), transparent (silica) and metallic (gold) surfaces. Furthermore, complex spatial patterns with micrometric dimensions have been defined with these nanolasers acting as localised emitters. Finally, we will also introduce our very recent results demonstrating the coupling of InP NW lasers with planar waveguide technology as a back-end hybrid integration technique.

  7. Nanoscale relaxation oscillator

    Science.gov (United States)

    Zettl, Alexander K.; Regan, Brian C.; Aloni, Shaul

    2009-04-07

    A nanoscale oscillation device is disclosed, wherein two nanoscale droplets are altered in size by mass transport, then contact each other and merge through surface tension. The device may also comprise a channel having an actuator responsive to mechanical oscillation caused by expansion and contraction of the droplets. It further has a structure for delivering atoms between droplets, wherein the droplets are nanoparticles. Provided are a first particle and a second particle on the channel member, both being made of a chargeable material, the second particle contacting the actuator portion; and electrodes connected to the channel member for delivering a potential gradient across the channel and traversing the first and second particles. The particles are spaced apart a specified distance so that atoms from one particle are delivered to the other particle by mass transport in response to the potential (e.g. voltage potential) and the first and second particles are liquid and touch at a predetermined point of growth, thereby causing merging of the second particle into the first particle by surface tension forces and reverse movement of the actuator. In a preferred embodiment, the channel comprises a carbon nanotube and the droplets comprise metal nanoparticles, e.g. indium, which is readily made liquid.

  8. Characterizing Nanoscale Transient Communication.

    Science.gov (United States)

    Chen, Yifan; Anwar, Putri Santi; Huang, Limin; Asvial, Muhamad

    2016-04-01

    We consider the novel paradigm of nanoscale transient communication (NTC), where certain components of the small-scale communication link are physically transient. As such, the transmitter and the receiver may change their properties over a prescribed lifespan due to their time-varying structures. The NTC systems may find important applications in the biomedical, environmental, and military fields, where system degradability allows for benign integration into life and environment. In this paper, we analyze the NTC systems from the channel-modeling and capacity-analysis perspectives and focus on the stochastically meaningful slow transience scenario, where the coherence time of degeneration Td is much longer than the coding delay Tc. We first develop novel and parsimonious models to characterize the NTC channels, where three types of physical layers are considered: electromagnetism-based terahertz (THz) communication, diffusion-based molecular communication (DMC), and nanobots-assisted touchable communication (TouchCom). We then revisit the classical performance measure of ϵ-outage channel capacity and take a fresh look at its formulations in the NTC context. Next, we present the notion of capacity degeneration profile (CDP), which describes the reduction of channel capacity with respect to the degeneration time. Finally, we provide numerical examples to demonstrate the features of CDP. To the best of our knowledge, the current work represents a first attempt to systematically evaluate the quality of nanoscale communication systems deteriorating with time.

  9. Small-area and compact CMOS emulator circuit for CMOS/nanoscale memristor co-design.

    Science.gov (United States)

    Shin, Sanghak; Choi, Jun-Myung; Cho, Seongik; Min, Kyeong-Sik

    2013-11-01

    In this paper, a CMOS emulator circuit that can reproduce nanoscale memristive behavior is proposed. The proposed emulator circuit can mimic the pinched hysteresis loops of nanoscale memristor memory's current-voltage relationship without using any resistor array, complicated circuit blocks, etc. that may occupy very large layout area. Instead of using a resistor array, other complicated circuit blocks, etc., the proposed emulator circuit can describe the nanoscale memristor's current-voltage relationship using a simple voltage-controlled resistor, where its resistance can be programmed by the stored voltage at the state variable capacitor. Comparing the layout area between the previous emulator circuit and the proposed one, the layout area of the proposed emulator circuit is estimated to be 32 times smaller than the previous emulator circuit. The proposed CMOS emulator circuit of nanoscale memristor memory will be very useful in developing hybrid circuits of CMOS/nanoscale memristor memory.

  10. Patterns of hybridization of nonnative cutthroat trout and hatchery rainbow trout with native redband trout in the Boise River, Idaho

    Science.gov (United States)

    Neville, Helen M.; Dunham, Jason B.

    2011-01-01

    Hybridization is one of the greatest threats to native fishes. Threats from hybridization are particularly important for native trout species as stocking of nonnative trout has been widespread within the ranges of native species, thus increasing the potential for hybridization. While many studies have documented hybridization between native cutthroat trout Oncorhynchus clarkii and nonnative rainbow trout O. mykiss, fewer have focused on this issue in native rainbow trout despite widespread threats from introductions of both nonnative cutthroat trout and hatchery rainbow trout. Here, we describe the current genetic (i.e., hybridization) status of native redband trout O. mykiss gairdneri populations in the upper Boise River, Idaho. Interspecific hybridization was widespread (detected at 14 of the 41 sampled locations), but high levels of hybridization between nonnative cutthroat trout and redband trout were detected in only a few streams. Intraspecific hybridization was considerably more widespread (almost 40% of sampled locations), and several local populations of native redband trout have been almost completely replaced with hatchery coastal rainbow trout O. mykiss irideus; other populations exist as hybrid swarms, some are in the process of being actively invaded, and some are maintaining genetic characteristics of native populations. The persistence of some redband trout populations with high genetic integrity provides some opportunity to conserve native genomes, but our findings also highlight the complex decisions facing managers today. Effective management strategies in this system may include analysis of the specific attributes of each site and population to evaluate the relative risks posed by isolation versus maintaining connectivity, identifying potential sites for control or eradication of nonnative trout, and long-term monitoring of the genetic integrity of remaining redband trout populations to track changes in their status.

  11. Rocket Science at the Nanoscale.

    Science.gov (United States)

    Li, Jinxing; Rozen, Isaac; Wang, Joseph

    2016-06-28

    Autonomous propulsion at the nanoscale represents one of the most challenging and demanding goals in nanotechnology. Over the past decade, numerous important advances in nanotechnology and material science have contributed to the creation of powerful self-propelled micro/nanomotors. In particular, micro- and nanoscale rockets (MNRs) offer impressive capabilities, including remarkable speeds, large cargo-towing forces, precise motion controls, and dynamic self-assembly, which have paved the way for designing multifunctional and intelligent nanoscale machines. These multipurpose nanoscale shuttles can propel and function in complex real-life media, actively transporting and releasing therapeutic payloads and remediation agents for diverse biomedical and environmental applications. This review discusses the challenges of designing efficient MNRs and presents an overview of their propulsion behavior, fabrication methods, potential rocket fuels, navigation strategies, practical applications, and the future prospects of rocket science and technology at the nanoscale.

  12. Nanoscale waveguiding methods.

    Science.gov (United States)

    Wang, Chia-Jean; Lin, Lih Y

    2007-05-01

    While 32 nm lithography technology is on the horizon for integrated circuit (IC) fabrication, matching the pace for miniaturization with optics has been hampered by the diffraction limit. However, development of nanoscale components and guiding methods is burgeoning through advances in fabrication techniques and materials processing. As waveguiding presents the fundamental issue and cornerstone for ultra-high density photonic ICs, we examine the current state of methods in the field. Namely, plasmonic, metal slot and negative dielectric based waveguides as well as a few sub-micrometer techniques such as nanoribbons, high-index contrast and photonic crystals waveguides are investigated in terms of construction, transmission, and limitations. Furthermore, we discuss in detail quantum dot (QD) arrays as a gain-enabled and flexible means to transmit energy through straight paths and sharp bends. Modeling, fabrication and test results are provided and show that the QD waveguide may be effective as an alternate means to transfer light on sub-diffraction dimensions.

  13. Anatomy of Nanoscale Propulsion.

    Science.gov (United States)

    Yadav, Vinita; Duan, Wentao; Butler, Peter J; Sen, Ayusman

    2015-01-01

    Nature supports multifaceted forms of life. Despite the variety and complexity of these forms, motility remains the epicenter of life. The applicable laws of physics change upon going from macroscales to microscales and nanoscales, which are characterized by low Reynolds number (Re). We discuss motion at low Re in natural and synthetic systems, along with various propulsion mechanisms, including electrophoresis, electrolyte diffusiophoresis, and nonelectrolyte diffusiophoresis. We also describe the newly uncovered phenomena of motility in non-ATP-driven self-powered enzymes and the directional movement of these enzymes in response to substrate gradients. These enzymes can also be immobilized to function as fluid pumps in response to the presence of their substrates. Finally, we review emergent collective behavior arising from interacting motile species, and we discuss the possible biomedical applications of the synthetic nanobots and microbots.

  14. Nonrandom patterns of genetic admixture expose the complex historical hybrid origin of unisexual leaf beetle species in the genus Calligrapha.

    Science.gov (United States)

    Montelongo, Tinguaro; Gómez-Zurita, Jesús

    2015-01-01

    Many unisexual animal lineages supposedly arose from hybridization. However, support for their putative hybrid origins mostly comes from indirect methodologies, which are rarely confirmatory. Here we provide compelling data indicating that tetraploid unisexual Calligrapha are true genetic mosaics obtained via analysis of mitochondrial DNA (mtDNA) and allelic variation and coalescence times for three single-copy nuclear genes (CPS, HARS, and Wg) in five of six unisexual Calligrapha and a representative sample of bisexual species. Nuclear allelic diversity in unisexuals consistently segregates in the gene pools of at least two but up to three divergent bisexual species, interpreted as putative parentals of interspecific hybridization crosses. Interestingly, their mtDNA diversity derives from an additional yet undiscovered older evolutionary lineage that is possibly the same for all independently originated unisexual species. One possibly extinct species transferred its mtDNA to several evolutionary lineages in a wave of hybridization events during the Pliocene, whereby descendant species retained a polymorphic mtDNA constitution. Recent hybridizations, in the Pleistocene and always involving females with the old introgressed mtDNA, seemingly occurred in the lineages leading to unisexual species, decoupling mtDNA introgression (and inferences derived from these data, such as timing and parentage) from subsequent acquisition of the new reproductive mode. These results illuminate an unexpected complexity in possible routes to animal unisexuality, with implications for the interpretation of ancient unisexuality. If the origin of unisexuality requires a mechanism where (1) hybridization is a necessary but insufficient condition and (2) multiple bouts of hybridization involving more than two divergent lineages are required, then the origins of several classical unisexual systems may have to be reassessed.

  15. Heterotic patterns in rapeseed (Brassica napus L.) using exotic germplasm for Chinese semi-winter hybrid breeding

    Institute of Scientific and Technical Information of China (English)

    Qian Lunwen; Chen Lunlin; Mei Jiaqin; Li Maoteng; Martin Frauen; Christian Jung; Qian Wei; Meng Jinling

    2013-01-01

    Chinese semi-winter rapeseed,genetically differing from winter and spring rapeseed,has been consid-ered to possess strong potential as parent in winter and spring rapeseed hybrid breeding programs. However,no de-tailed researches have been documented whether winter and spring rapeseed lines have potential for Chinese semi-winter rapeseed hybrid breeding. The objectives of this study are to estimate the potential of winter and spring rapeseed for semi-winter rapeseed hybrid breeding,and to investigate the association of general combining ability (GCA) with adaptation of parental lines by combining with the data in our previous studies. Four winter and four spring male sterile lines were crossed with 14 Chinese semi-winter rapeseed lines to develop 112 hybrids,which were evaluated together with their parents for seed yield under three environments in China. The exotic parental lines were not adapted to local environment as demonstrated by late flowering,low seed weight and poor seed yield per se. However,the hybrids,especially derived from winter rapeseed exhibited strong heterosis for seed yield,indicating that winter rapeseed germplasm has a great potential for rapeseed hybrid breeding in China. Our data suggested a strong association of GCA with their adaptation ability of parental lines,since high to middle cor-relations were found for local parental lines and low correlations for exotic parental lines under spring,winter and semi-winter eco-growth environments. The hybrid breeding program using exotic germplasm in rapeseed was dis-cussed.

  16. Interferometer -based Technology for Optical Nanoscale Inspection

    Directory of Open Access Journals (Sweden)

    Ryabko M.

    2014-02-01

    Full Text Available We demonstrate the interferometer-based approach for nanoscale grating Critical Dimension (CD measurements and prove the possibility to achieve no worse than 10 nm accuracy of measurements for 100 nm pitch gratings. The approach is based on phase shift measurement of light fields specularly reflected from periodical pattern and adjacent substrate with subsequent comparison between experimental and simulation results. RCWA algorithm is used to fit the measured results and extract the CD value. It is shown that accuracy of CD value measurement depends rather on the grating’s CD/pitch ratio than its CD value

  17. Recent advances with a hybrid micro-pattern gas detector operated in low pressure H2 and He, for AT-TPC applications

    CERN Document Server

    Cortesi, Marco; Bazin, Daniel; Beceiro-Novo, Saul; Yurkon, John; Tanani, Rim Soussi; Wolff, Michael; Stolz, Andreas

    2015-01-01

    In view of a possible application as a charge-particle track readout for an Active-Target Time Projection Chamber (AT-TPC), the operational properties and performances of a hybrid Micro-Pattern Gaseous Detector (MPGD) were investigated in pure low-pressure Hydrogen (H2) and Helium (He). The detector consists of a MICROMesh GAseous Structure (MICROMEGAS) coupled to a single- or multi-cascade THick Gaseous Electron Multiplier (THGEM) as a pre-amplification stage. This study reports of the effective gain dependence of the hybrid-MPGD at relevant pressure (in the range of 200-760 torr) for different detector arrangements. The results of this work are relevant in the field of avalanche mechanism in low-pressure, low-mass noble gases, in particularly for applications of MPGD end-cap readout for active-target Time Projection Chambers (TPC) in the field of nuclear physics and nuclear astrophysics.

  18. Parallel optical nanolithography using nanoscale bowtie apertures

    Science.gov (United States)

    Uppuluri, Sreemanth M. V.

    Over the past two decades various branches of science and engineering have developed techniques for producing nanoscopic light sources for different applications such as imaging, detection and fabrication. These areas include near-field scanning optical microscopy (NSOM), surface-enhanced Raman scattering and detection (SERS), plasmonics and so on. In particular nanolithography techniques have been developed to produce feature sizes in the sub-100 nm length scales. These processes include variations of standard photolithography process to achieve high resolution, optical fiber-based near-field lithography, surface plasmon assisted nanolithography, interference optical lithography and so on. This work presents a study of the viability of using nanoscale bowtie apertures for nanolithography. Bowtie apertures exhibit a unique property of supporting a propagating TE10 mode at wavelengths of light in the visible and near-UV regimes. The energy of this mode is concentrated in the gap region of the aperture and thus these apertures have the potential to produce high intensity nanoscale light spots that can be used for nano-patterning applications. We demonstrate this capability of nanoscale bowtie apertures by patterning photoresist to obtain resolution less than 100 nm. Initially we present the results from static lithography experiments and show that the ridge apertures of different shapes -- C, H and bowtie produce holes in the photoresist of dimensions around 50-60 nm. Subsequently we address the issues involved in using these apertures for nano directwriting. We show that chromium thin-films offer a viable solution to produce high quality metal films of surface roughness less than 1 nm over an area of 25 mum2. This is indeed important to achieve intimate contact between the apertures and the photoresist surface. We also explain ways to decrease friction between the mask and photoresist surfaces during nano direct-writing. In addition, to decrease the contact force

  19. Quantum machines at the nanoscale

    OpenAIRE

    2015-01-01

    Thermodynamic machines have been studied for two centuries. The rapid advancement in fabrication techniques of the last decades has lead to size reduction from the macroscale to nanoscale. At the nanoscale, quantum properties become important and have thus to be fully taken into account. Quantum heat engines have been the subject of extensive theoretical studies in the last fifty years. However, while classical micro heat engines have been fabricated, to date no quantum heat engine has bee...

  20. Nanoscale technology in biological systems

    CERN Document Server

    Greco, Ralph S; Smith, R Lane

    2004-01-01

    Reviewing recent accomplishments in the field of nanobiology Nanoscale Technology in Biological Systems introduces the application of nanoscale matrices to human biology. It focuses on the applications of nanotechnology fabrication to biomedical devices and discusses new physical methods for cell isolation and manipulation and intracellular communication at the molecular level. It also explores the application of nanobiology to cardiovascular diseases, oncology, transplantation, and a range of related disciplines. This book build a strong background in nanotechnology and nanobiology ideal for

  1. Energy Use in Nanoscale Manufacturing

    OpenAIRE

    Zhang, Teresa; Boyd, Sarah; Vijayaraghavan, Athulan; Dornfeld, David

    2006-01-01

    This paper presents an overview of key nanoscale manufacturing technologies, and qualitatively examines their fundamental process requirements with respect to energy demand. The processes requirements are related to semiconductor manufacturing, where applicable, and gaps in our understanding of these processes on the production scale are identified as goals for the research community. Finally, the paper proposes a framework for the systematic analysis of energy use in nanoscale manufacturing ...

  2. Synthesis, dynamics and photophysics of nanoscale systems

    Science.gov (United States)

    Mirkovic, Tihana

    The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained

  3. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert

    2008-11-18

    Polymer nanocomposites (nanoparticles dispersed in a polymer matrix) have been the subject of intense research for almost two decades in both academic and industrial settings. This interest has been fueled by the ability of nanocomposites to not only improve the performance of polymers, but also by their ability to introduce new properties. Yet, there are still challenges that polymer nanocomposites must overcome to reach their full potential. In this Research News article we discuss a new class of hybrids termed nanoparticle ionic materials (NIMS). NIMS are organic-inorganic hybrid materials comprising a nanoparticle core functionalized with a covalently tethered ionic corona. They are facilely engineered to display flow properties that span the range from glassy solids to free flowing liquids. These new systems have unique properties that can overcome some of the challenges facing nanocomosite materials. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

  4. Nanoscale waveguiding methods

    Directory of Open Access Journals (Sweden)

    Wang Chia-Jean

    2007-01-01

    Full Text Available AbstractWhile 32 nm lithography technology is on the horizon for integrated circuit (IC fabrication, matching the pace for miniaturization with optics has been hampered by the diffraction limit. However, development of nanoscale components and guiding methods is burgeoning through advances in fabrication techniques and materials processing. As waveguiding presents the fundamental issue and cornerstone for ultra-high density photonic ICs, we examine the current state of methods in the field. Namely, plasmonic, metal slot and negative dielectric based waveguides as well as a few sub-micrometer techniques such as nanoribbons, high-index contrast and photonic crystals waveguides are investigated in terms of construction, transmission, and limitations. Furthermore, we discuss in detail quantum dot (QD arrays as a gain-enabled and flexible means to transmit energy through straight paths and sharp bends. Modeling, fabrication and test results are provided and show that the QD waveguide may be effective as an alternate means to transfer light on sub-diffraction dimensions.

  5. Capillarity at the nanoscale.

    Science.gov (United States)

    van Honschoten, Joost W; Brunets, Nataliya; Tas, Niels R

    2010-03-01

    In this critical review we treat the phenomenon of capillarity in nanoscopic confinement, based on application of the Young-Laplace equation. In classical capillarity the curvature of the meniscus is determined by the confining geometry and the macroscopic contact angle. We show that in narrow confinement the influence of the disjoining pressure and the related wetting films have to be considered as they may significantly change the meniscus curvature. Nanochannel based static and dynamic capillarity experiments are reviewed. A typical effect of nanoscale confinement is the appearance of capillarity induced negative pressure. Special attention is paid to elasto-capillarity and electro-capillarity. The presence of electric fields leads to an extra stress term to be added in the Young-Laplace equation. A typical example is the formation of the Taylor cone, essential in the theory of electrospray. Measurements of the filling kinetics of nanochannels with water and aqueous salt solutions are discussed. These experiments can be used to characterize viscosity and apparent viscosity effects of water in nanoscopic confinement. In the final section we show four examples of appearances of capillarity in engineering and in nature (112 references).

  6. Patterns of DNA methylation in development, division of labor and hybridization in an ant with genetic caste determination.

    Directory of Open Access Journals (Sweden)

    Chris R Smith

    Full Text Available BACKGROUND: DNA methylation is a common regulator of gene expression, including acting as a regulator of developmental events and behavioral changes in adults. Using the unique system of genetic caste determination in Pogonomyrmex barbatus, we were able to document changes in DNA methylation during development, and also across both ancient and contemporary hybridization events. METHODOLOGY/PRINCIPAL FINDINGS: Sodium bisulfite sequencing demonstrated in vivo methylation of symmetric CG dinucleotides in P. barbatus. We also found methylation of non-CpG sequences. This validated two bioinformatics methods for predicting gene methylation, the bias in observed to expected ratio of CpG dinucleotides and the density of CpG/TpG single nucleotide polymorphisms (SNP. Frequencies of genomic DNA methylation were determined for different developmental stages and castes using ms-AFLP assays. The genetic caste determination system (GCD is probably the product of an ancestral hybridization event between P. barbatus and P. rugosus. Two lineages obligately co-occur within a GCD population, and queens are derived from intra-lineage matings whereas workers are produced from inter-lineage matings. Relative DNA methylation levels of queens and workers from GCD lineages (contemporary hybrids were not significantly different until adulthood. Virgin queens had significantly higher relative levels of DNA methylation compared to workers. Worker DNA methylation did not vary among developmental stages within each lineage, but was significantly different between the currently hybridizing lineages. Finally, workers of the two genetic caste determination lineages had half as many methylated cytosines as workers from the putative parental species, which have environmental caste determination. CONCLUSIONS/SIGNIFICANCE: These results suggest that DNA methylation may be a conserved regulatory mechanism moderating division of labor in both bees and ants. Current and historic

  7. Analysis of Differential Gene Expression Pattern in Brassica napus Hybrid Huayouza 6 and Its Parents Using Arabidopsis cDNA Microarray

    Institute of Scientific and Technical Information of China (English)

    SHEN Jun-ru; WU Jian-yong; ZHANG Jian; LIU Ping-wu; YANG Guang-sheng

    2006-01-01

    Huayouza 6, a new semi-winter Brassica napus variety with high-yield, good quality, prematurity and extensive adaptability, was derived from the cross between the female parent 8086A and male parent 7-5. Two cDNA-based Arabidopisis microarray were used to analyze gene differential expression in bud of an elite B. napus hybrid Huayouza6 and its parents,in which there were 83 over-expression transcripts and 331 under-expression transcripts between Huayouza 6 and its female parent 8086A and 94 over-expression transcripts, and 423 under-expression transcripts were demonstrated betweenHuayouza 6 and its male parent 7-5. Further analysis showed that there were significant number of genes responsible for photosynthesis, and its implication for heterosis was discussed. Northern analysis of phosphoribulokinase coincided with its expression pattern derived from hybridization of Arabidopsis cDNA microarray and B. napus mRNA, this system of heterologous hybridization analysis should be applicable to other close relatives of Arabidopsis thaliana.

  8. Alleviating Surface Degradation of Nickel-Rich Layered Oxide Cathode Material by Encapsulating with Nanoscale Li-Ions/Electrons Superionic Conductors Hybrid Membrane for Advanced Li-Ion Batteries.

    Science.gov (United States)

    Li, Lingjun; Xu, Ming; Yao, Qi; Chen, Zhaoyong; Song, Liubin; Zhang, Zhian; Gao, Chunhui; Wang, Peng; Yu, Ziyang; Lai, Yanqing

    2016-11-16

    Nickel-rich layered oxide cathode materials for advanced lithium-ion batteries have received much attention recently because of their high specific capacities and significant reduction of cost. However, these cathodes are facing a fundamental challenge of loss in performance as a result of surface lithium residue, side reactions with the electrolyte and structure rearrangement upon long-term cycling. Herein, by capturing the lithium residue on the surface of LiNi0.8Co0.1Mn0.1O2 (NCM) cathode material as Li source, we propose a hybrid coating strategy incorporating lithium ions conductor LixAlO2 with superconductor LixTi2O4 to overcome those obstinate issues. By taking full advantage of this unique hybrid nanomembrane coating architecture, both the lithium ion diffusion ability and electronic conductivity of LiNi0.8Co0.1Mn0.1O2 cathode material are improved, resulting in remarkably enhanced electrochemical performances during high voltage operation, including good cycle performance, high reversible capacity, and excellent rate capability. A high initial discharge capacity of 227 mAh g(-1) at 4.4 V cutoff voltage with Coulombic efficiency of 87.3%, and reversible capacity of 200 mAh g(-1) with 98% capacity retention after 100 cycles at a current density of 0.5 C can be attained. The improved electrochemical performance can be attributed to the synergetic contribution from the removal of lithium residues and the unique hybrid nanomembrane coating architecture. Most importantly, this surface modification technique could save some cost, simplify the technical procedure, and show great potential to optimize battery performance, apply in a large scale and extend to all nickel-rich cathode material.

  9. PREFACE: Nanoscale science and technology

    Science.gov (United States)

    Bellucci, Stefano

    2008-11-01

    material. The results show the emergence of specific interactions of cross-linking between a thermosetting matrix and amino-functionalized SWNTs during the cure reaction with an improvement of the mechanical properties with respect to those prepared with unfunctionalized SWNTs. The possibility of using amino-functionalized SWNT to make a 'mix and match' approach towards classes of hybrid materials was reported suggesting the possibility of tuning the electrical properties by combining the electric field in the assembling processing. Moreover, it was demonstrated as electrophoretically deposited SWNT thin films provide a simple route to obtain layered functional nanostructures by growing homogeneous films of carbon nanotubes and infiltrating polymer or monomer, followed by in situ polymerization. Some examples where electrophoretically deposited SWCNT films were infiltrated with monomer and then the monomer was polymerized were reported. The invited lecture by S D'Auria explored the advantages of using either enzymes or binding proteins to develop non-consuming substrate fluorescence nano-biosensors. He reported a novel approach to address the consumption of substrate by enzyme-based biosensors, namely the utilization of apo-enzymes as non-active forms of proteins which are still able to bind the ligand but cannot transform it into product. He also reported recent studies in which fluorescence labelling proteins by a fluorescent probe allows a wireless monitoring of toxic compounds. Then, he presented a cutting-edge methodology for the detection of target analytes at very low concentration, namely single molecule detection. C Falessi described how the 'Finmeccanica Focus Group Nano' is coordinating a multiscale nanoscience engineering integration initiative that is an emerging and unified strategy to link the customer operative requirements with innovative high-tech product. He introduced the audience to the 'NanoTechnology Multiscale Project (NMP)', as a complete

  10. Hybrid zone origins, species boundaries, and the evolution of wing-pattern diversity in a polytypic species complex of North American admiral butterflies (Nymphalidae: Limenitis).

    Science.gov (United States)

    Mullen, Sean P; Dopman, Erik B; Harrison, Richard G

    2008-06-01

    Hybrid zones present opportunities to study the effects of gene flow, selection, and recombination in natural populations and, thus, provide insights into the genetic and phenotypic changes that occur early in speciation. Here we investigate a hybrid zone between mimetic (Limenitis arthemis astyanax) and nonmimetic (Limenitis arthemis arthemis) populations of admiral butterflies using DNA sequence variation from mtDNA and seven nuclear gene loci. We find three distinct mitochondrial clades within this complex, and observe a strong overall concordance between wing-pattern phenotypes and mitochondrial variation. Nuclear gene genealogies, in contrast, revealed no evidence of exclusivity for either wing-pattern phenotype, suggesting incomplete barriers to gene exchange and/or insufficient time for lineage sorting. Coalescent simulations indicate that gene flow between these two subspecies is highly asymmetric, with the majority of migration occurring from mimetic into nonmimetic populations. Selective sweeps of alleles responsible for mimetic phenotypes may have occurred more than once when mimetic and nonmimetic Limenitis occurred together in the presence of the model (Battus philenor).

  11. Design of Solar/Electric Powered Hybrid Vehicle (SEPHV) System with Charge Pattern Optimization for Energy Cost

    OpenAIRE

    T Balamurugan; Dr.S.Manoharan

    2014-01-01

    This paper proposes a Solar Electric Powered Hybrid Vehicle (SEPHV) system which solves the major problems of fuel and pollution. An electric vehicle usually uses a battery which has been charged by external electrical power supply. All recent electric vehicles present a drive on AC power supplied motor. An inverter set is required to be connected with the battery through which AC power is converted to DC power. During this conversion many losses take place and also the maintenance cost of th...

  12. Tailorable Stimulated Brillouin Scattering in Nanoscale Silicon Waveguides

    CERN Document Server

    Shin, Heedeuk; Jarecki, Robert; Cox, Jonathan A; Olsson, Roy H; Starbuck, Andrew; Wang, Zheng; Rakich, Peter T

    2013-01-01

    While nanoscale modal confinement radically enhances a variety of nonlinear light-matter interactions within silicon waveguides, traveling-wave stimulated Brillouin scattering nonlinearities have never been observed in silicon nanophotonics. Through a new class of hybrid photonic-phononic waveguides, we demonstrate tailorable traveling-wave forward stimulated Brillouin scattering in nanophotonic silicon waveguides for the first time, yielding 3000 times stronger forward SBS responses than any previous waveguide system. Simulations reveal that a coherent combination of electrostrictive forces and radiation pressures are responsible for greatly enhanced photon-phonon coupling at nano-scales. Highly tailorable Brillouin nonlinearities are produced by engineering the structure of a membrane-suspended waveguide to yield Brillouin resonances from 1 to 18 GHz through high quality-factor (>1000) phonon modes. Such wideband and tailorable stimulated Brillouin scattering in silicon photonics could enable practical real...

  13. Nanoscale phase change memory materials.

    Science.gov (United States)

    Caldwell, Marissa A; Jeyasingh, Rakesh Gnana David; Wong, H-S Philip; Milliron, Delia J

    2012-08-01

    Phase change memory materials store information through their reversible transitions between crystalline and amorphous states. For typical metal chalcogenide compounds, their phase transition properties directly impact critical memory characteristics and the manipulation of these is a major focus in the field. Here, we discuss recent work that explores the tuning of such properties by scaling the materials to nanoscale dimensions, including fabrication and synthetic strategies used to produce nanoscale phase change memory materials. The trends that emerge are relevant to understanding how such memory technologies will function as they scale to ever smaller dimensions and also suggest new approaches to designing materials for phase change applications. Finally, the challenges and opportunities raised by integrating nanoscale phase change materials into switching devices are discussed.

  14. Fabrication of nanoscale electrostatic lenses

    Science.gov (United States)

    Sinno, I.; Sanz-Velasco, A.; Kang, S.; Jansen, H.; Olsson, E.; Enoksson, P.; Svensson, K.

    2010-09-01

    The fabrication of cylindrical multi-element electrostatic lenses at the nanoscale presents a challenge; they are high-aspect-ratio structures that should be rotationally symmetric, well aligned and freestanding, with smooth edges and flat, clean surfaces. In this paper, we present the fabrication results of a non-conventional process, which uses a combination of focused gallium ion-beam milling and hydrofluoric acid vapor etching. This process makes it possible to fabricate nanoscale electrostatic lenses down to 140 nm in aperture diameter and 4.2 µm in column length, with a superior control of the geometry as compared to conventional lithography-based techniques.

  15. NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

    Science.gov (United States)

    This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

  16. A Hybrid One-Way ANOVA Approach for the Robust and Efficient Estimation of Differential Gene Expression with Multiple Patterns

    OpenAIRE

    Mohammad Manir Hossain Mollah; Rahman Jamal; Norfilza Mohd Mokhtar; Roslan Harun; Md. Nurul Haque Mollah

    2015-01-01

    Background Identifying genes that are differentially expressed (DE) between two or more conditions with multiple patterns of expression is one of the primary objectives of gene expression data analysis. Several statistical approaches, including one-way analysis of variance (ANOVA), are used to identify DE genes. However, most of these methods provide misleading results for two or more conditions with multiple patterns of expression in the presence of outlying genes. In this paper, an attempt ...

  17. Nanoscale Turing structures

    DEFF Research Database (Denmark)

    Dziekan, Piotr; Hansen, Jesper Schmidt; Nowakowski, Bogdan

    2014-01-01

    Formation of Turing patterns of nanoscopic length scale is simulated using molecular dynamics. Based on Fourier spectra of the concentrations of species, we compare stabilities of the structures of different wavelengths and for different intermolecular potentials. Long range attraction is shown t...

  18. Nanoscale chemical interaction enhances the physical properties of bioglass composites.

    Science.gov (United States)

    Ravarian, Roya; Zhong, Xia; Barbeck, Mike; Ghanaati, Shahram; Kirkpatrick, Charles James; Murphy, Ciara M; Schindeler, Aaron; Chrzanowski, Wojciech; Dehghani, Fariba

    2013-10-22

    Bioglasses are favorable biomaterials for bone tissue engineering; however, their applications are limited due to their brittleness. In addition, the early failure in the interface is a common problem of composites of bioglass and a polymer with high mechanical strength. This effect is due to the phase separation, nonhomogeneous mixture, nonuniform mechanical strength, and different degradation properties of two compounds. To address these issues, in this study a nanoscale interaction between poly(methyl methacrylate) (PMMA) and bioactive glass was formed via silane coupling agent (3-trimethoxysilyl)propyl methacrylate (MPMA). A monolith was produced at optimum composition from this hybrid by the sol-gel method at 50 °C with a rapid gelation time (hybrid. The in vivo studies in mice demonstrated that the integrity of the hybrids was maintained in subcutaneous implantation. They induced mainly a mononuclear phagocytic tissue reaction with a low level of inflammation, while bioglass provoked a tissue reaction with TRAP-positive multinucleated giant cells. These results demonstrated that the presence of a nanoscale interaction between bioglass and PMMA affects the properties of bioglass and broadens its potential applications for bone replacement.

  19. Design of Solar/Electric Powered Hybrid Vehicle (SEPHV System with Charge Pattern Optimization for Energy Cost

    Directory of Open Access Journals (Sweden)

    T.Balamurugan

    2014-01-01

    Full Text Available This paper proposes a Solar Electric Powered Hybrid Vehicle (SEPHV system which solves the major problems of fuel and pollution. An electric vehicle usually uses a battery which has been charged by external electrical power supply. All recent electric vehicles present a drive on AC power supplied motor. An inverter set is required to be connected with the battery through which AC power is converted to DC power. During this conversion many losses take place and also the maintenance cost of the AC System is very high. The proposed topology has the most feasible solar/electric power generation system mounted on the vehicle to charge the battery during all durations. With a view of providing ignited us to develop this “Solar/Electric Powered Hybrid Vehicle” [SEPHV].This multi charging vehicle can charge itself from both solar and electric power. The vehicle is altered out of a Maruti Omni vehicle by replacing its engine with a 1.2HP, 24V Permanent Magnet DC [PMDC] Motor. The Supply to the motor is obtained from a battery set of 12V, 150AH. The household electric supply of 230V is reduced with a step-down transformer to 48V and then it is converted to the DC with a rectifying unit to charge the battery. Two solar panels each with a rating of 230watts are attached to the top of the Vehicle to grab the solar energy and is controlled with a help of charge controller. The SEPHV can be driven by 1.2 HP PMDC motor consisting of two 230 watts PV panel in the voltage rating of 24 V. The power which is absorbed by the PV panel is stored into the four 150 AH 12 V batteries. When there is no presence of sun, electric power supply act as an auxiliary energy source. For controlling speed of the motor, a switch is designed with four tapping, provided with different values of resistance at each tapping. It acts as a speed control switch for Solar/Electric Powered Hybrid Vehicle. This type of technique is to reduce the running cost and increasing the running

  20. Fabrication of nanoscale electrostatic lenses

    NARCIS (Netherlands)

    Sinno, I.; Sanz-Velasco, A.; Kang, S.; Jansen, H.; Olsson, E.; Enoksson, P.; Svensson, K.

    2010-01-01

    The fabrication of cylindrical multi-element electrostatic lenses at the nanoscale presents a challenge; they are high-aspect-ratio structures that should be rotationally symmetric, well aligned and freestanding, with smooth edges and flat, clean surfaces. In this paper, we present the fabrication r

  1. IR nanoscale spectroscopy and imaging

    Science.gov (United States)

    Kennedy, Eamonn; Yarrow, Fiona; Rice, James H.

    2011-10-01

    Sub diffraction limited infrared absorption imaging was applied to hemoglobin by coupling IR optics with an atomic force microscope. Comparisons between the AFM topography and IR absorption images of micron sized hemoglobin features are presented, along with nanoscale IR spectroscopic analysis of the metalloprotein.

  2. Source apportionment for sediment PAHs using hybrid genetic pattern search treatment of a chemical mass balance receptor model: application to the Pearl River Delta region, China.

    Science.gov (United States)

    Wu, Jin; Teng, Yanguo; Chen, Haiyang

    2014-10-01

    In order to solve the collinear problem and improve the estimation accuracy of the chemical mass balance (CMB) model which can be essentially regarded as a constrained optimization process, in this study, a hybrid genetic pattern search algorithm (HGPS) was proposed and applied to apportion the source contributions for sediment polycyclic aromatic hydrocarbons (PAHs) in the Pearl River Delta (PRD) region, China. Simulation results with developed synthetic datasets indicated that the estimated source contributions by HGPS were more close to the true values than CMB8.2. Utilizing the HGPS-CMB, residential coal and traffic tunnel were apportioned as the major sources of sediment PAHs in the PRD region. For freshwater surface sediments, the average contribution from residential coal ranged from 32 to 55%, and traffic tunnel ranged from 13 to 33%, while the major sources for marine sediments were traffic tunnel (10 ~ 56%). These results provide information for developing better PAH pollution control strategies for the PRD.

  3. Nanoscale pillar hypersonic surface phononic crystals

    Science.gov (United States)

    Yudistira, D.; Boes, A.; Graczykowski, B.; Alzina, F.; Yeo, L. Y.; Sotomayor Torres, C. M.; Mitchell, A.

    2016-09-01

    We report on nanoscale pillar-based hypersonic phononic crystals in single crystal Z-cut lithium niobate. The phononic crystal is formed by a two-dimensional periodic array of nearly cylindrical nanopillars 240 nm in diameter and 225 nm in height, arranged in a triangular lattice with a 300-nm lattice constant. The nanopillars are fabricated by the recently introduced nanodomain engineering via laser irradiation of patterned chrome followed by wet etching. Numerical simulations and direct measurements using Brillouin light scattering confirm the simultaneous existence of nonradiative complete surface phononic band gaps. The band gaps are found below the sound line at hypersonic frequencies in the range 2-7 GHz, formed from local resonances and Bragg scattering. These hypersonic structures are realized directly in the piezoelectric material lithium niobate enabling phonon manipulation at significantly higher frequencies than previously possible with this platform, opening new opportunities for many applications in plasmonic, optomechanic, microfluidic, and thermal engineering.

  4. The synthesis and properties of nanoscale ionic materials

    KAUST Repository

    Rodriguez, Robert Salgado

    2010-02-17

    In this article we discuss the effect of constituents on structure, flow, and thermal properties of nanoscale ionic materials (NIMs). NIMs are a new class of nanohybrids consisting of a nanometer-sized core, a charged corona covalently attached to the core, and an oppositely charged canopy. The hybrid nature of NIMs allows for their properties to be engineered by selectively varying their components. The unique properties associated with these systems can help overcome some of the issues facing the implementation of nanohybrids to various commercial applications, including carbon dioxide capture,water desalinization and as lubricants. Copyright © 2010 John Wiley & Sons, Ltd.

  5. Stochastic behavior of nanoscale dielectric wall buckling

    Science.gov (United States)

    Friedman, Lawrence H.; Levin, Igor; Cook, Robert F.

    2016-01-01

    The random buckling patterns of nanoscale dielectric walls are analyzed using a nonlinear multi-scale stochastic method that combines experimental measurements with simulations. The dielectric walls, approximately 200 nm tall and 20 nm wide, consist of compliant, low dielectric constant (low-k) fins capped with stiff, compressively stressed TiN lines that provide the driving force for buckling. The deflections of the buckled lines exhibit sinusoidal pseudoperiodicity with amplitude fluctuation and phase decorrelation arising from stochastic variations in wall geometry, properties, and stress state at length scales shorter than the characteristic deflection wavelength of about 1000 nm. The buckling patterns are analyzed and modeled at two length scales: a longer scale (up to 5000 nm) that treats randomness as a longer-scale measurable quantity, and a shorter-scale (down to 20 nm) that treats buckling as a deterministic phenomenon. Statistical simulation is used to join the two length scales. Through this approach, the buckling model is validated and material properties and stress states are inferred. In particular, the stress state of TiN lines in three different systems is determined, along with the elastic moduli of low-k fins and the amplitudes of the small-scale random fluctuations in wall properties—all in the as-processed state. The important case of stochastic effects giving rise to buckling in a deterministically sub-critical buckling state is demonstrated. The nonlinear multiscale stochastic analysis provides guidance for design of low-k structures with acceptable buckling behavior and serves as a template for how randomness that is common to nanoscale phenomena might be measured and analyzed in other contexts. PMID:27330220

  6. High-rate nanoscale offset printing process using directed assembly and transfer of nanomaterials.

    Science.gov (United States)

    Cho, Hanchul; Somu, Sivasubramanian; Lee, Jin Young; Jeong, Hobin; Busnaina, Ahmed

    2015-03-11

    High-rate nanoscale offset printing using a newly developed reusable template enables the assembly of nanomaterials into nanostructures followed by their transfer onto a flexible substrate in a few minutes. The developed template can potentially be reused more than 100 times in the offset printing process without any additional functionalization. This approach provides a new way for the printing of flexible devices with nanoscale patterns.

  7. High yield, single droplet electrode arrays for nanoscale printed electronics.

    Science.gov (United States)

    Caironi, Mario; Gili, Enrico; Sakanoue, Tomo; Cheng, Xiaoyang; Sirringhaus, Henning

    2010-03-23

    In this work we demonstrate two building blocks of a scalable manufacturing technology for nanoscale electronic devices based on direct-write printing: an architecture for high-yield printing of electrode gaps with 100 nm dimension and a low-temperature silver complex ink for integration of organic materials with high conductivity metal interconnects. We use single printed droplets that are made to dewet slowly from each other to allow reliable, high yield patterning even in the presence of certain surface defects.

  8. Computational Fluid Dynamics Study of Molten Steel Flow Patterns and Particle-Wall Interactions Inside a Slide-Gate Nozzle by a Hybrid Turbulent Model

    Science.gov (United States)

    Mohammadi-Ghaleni, Mahdi; Asle Zaeem, Mohsen; Smith, Jeffrey D.; O'Malley, Ronald

    2016-10-01

    Melt flow patterns and turbulence inside a slide-gate throttled submerged entry nozzle (SEN) were studied using Detached-Eddy Simulation (DES) model, which is a combination of Reynolds-Averaged Navier-Stokes (RANS) and Large-Eddy Simulation (LES) models. The DES switching criterion between RANS and LES was investigated to closely reproduce the flow structures of low and high turbulence regions similar to RANS and LES simulations, respectively. The melt flow patterns inside the nozzle were determined by k- ɛ (a RANS model), LES, and DES turbulent models, and convergence studies were performed to ensure reliability of the results. Results showed that the DES model has significant advantages over the standard k- ɛ model in transient simulations and in regions containing flow separation from the nozzle surface. Moreover, due to applying a hybrid approach, DES uses a RANS model at wall boundaries which resolves the extremely fine mesh requirement of LES simulations, and therefore it is computationally more efficient. Investigation of particle distribution inside the nozzle and particle adhesion to the nozzle wall also reveals that the DES model simulations predict more particle-wall interactions compared to LES model.

  9. Molecular characterization, expression patterns, and polymorphism of a differentially expressed porcine gene (PYGM) isolated by suppression subtractive hybridization and two-dimensional gel electrophoresis analysis.

    Science.gov (United States)

    Xu, Yongjie; Yu, Wenmin; Feng, Xiaoting; Xie, Hongtao; Xiong, Yuanzhu

    2012-01-01

    Suppression subtractive hybridization was performed to detect the differences in gene expression of porcine longissimus dorsi muscles between Large White and Chinese Meishan pigs. An upregulated gene in Large White that shared high homology with human muscle glycogen phosphorylase (PYGM) was identified. The porcine PYGM gene contains an open reading frame encoding 842 amino acid residues with 26 and 283 nucleotides in the 5' and 3' untranslated regions, respectively. Tissue distribution analysis indicated that porcine PYGM mRNAs are highly expressed in all tissues. Expression pattern of PYGM was similar in the two breeds. Both breeds had the highest expression levels when 120 days old (p<0.01), and PYGM was upregulated during skeletal muscle development. A similar expression pattern of PYGM in protein level was also observed by differential proteome analysis of skeletal muscle development using two-dimensional gel electrophoresis and mass spectroscopy. The mRNA abundance of PYGM in Large White was higher than Meishan at all four stages (p<0.05). Moreover, a G/T mutation in exon 8 was identified and association analysis with meat quality traits showed that it was significantly associated with lean meat percentage (p<0.05). Our data may provide further insight into the molecular mechanisms responsible for breed-specific differences in porcine growth and meat quality.

  10. Optical antennas as nanoscale resonators

    CERN Document Server

    Agio, Mario

    2011-01-01

    Recent progress in nanotechnology has enabled us to fabricate subwavelength architectures that function as antennas for improving the exchange of optical energy with nanoscale matter. We describe the main features of optical antennas for enhancing quantum emitters and review designs that increase the spontaneous emission rate by orders of magnitude from the ultraviolet up to the near-infrared spectral range. To further explore how optical antennas may lead to unprecedented regimes of light-matter interaction, we draw a relationship between metal nanoparticles, radio-wave antennas and optical resonators. Our analysis points out how optical antennas may function as nanoscale resonators and how these may offer unique opportunities with respect to state-of-the-art microcavities.

  11. Optical antennas as nanoscale resonators.

    Science.gov (United States)

    Agio, Mario

    2012-02-07

    Recent progress in nanotechnology has enabled us to fabricate sub-wavelength architectures that function as antennas for improving the exchange of optical energy with nanoscale matter. We describe the main features of optical antennas for enhancing quantum emitters and review the designs that increase the spontaneous emission rate by orders of magnitude from the ultraviolet up to the near-infrared spectral range. To further explore how optical antennas may lead to unprecedented regimes of light-matter interactions, we draw a relationship between metal nanoparticles, radio-wave antennas and optical resonators. Our analysis points out how optical antennas may function as nanoscale resonators and how these may offer unique opportunities with respect to state-of-the-art microcavities.

  12. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2010-07-27

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  13. Nanoscale deformation mechanisms in bone.

    Science.gov (United States)

    Gupta, Himadri S; Wagermaier, Wolfgang; Zickler, Gerald A; Raz-Ben Aroush, D; Funari, Sérgio S; Roschger, Paul; Wagner, H Daniel; Fratzl, Peter

    2005-10-01

    Deformation mechanisms in bone matrix at the nanoscale control its exceptional mechanical properties, but the detailed nature of these processes is as yet unknown. In situ tensile testing with synchrotron X-ray scattering allowed us to study directly and quantitatively the deformation mechanisms at the nanometer level. We find that bone deformation is not homogeneous but distributed between a tensile deformation of the fibrils and a shearing in the interfibrillar matrix between them.

  14. Performance and variability patterns in wood properties and growth traits in the parents, F1 and F2 generation hybrid clones of Populus deltoides

    Institute of Scientific and Technical Information of China (English)

    P. K. Pande; R. C. Dhiman

    2011-01-01

    The performance and variability patterns in the wood ele- ment's dimensions, specific gravity and growth parameters namely ramet height and GBH were evaluated in 16 clones of parents, F1 and F2 hy- brids of Populus deltoides Bartr. Ex Marsh. Ramet radial variations were non-significant, while inter-clonal variations due to interaction of clone/replication were significant for all the wood traits except vessel element length. Inter-clonal variations were significant only for fiber length and fiber wall thickness. Fiber length and specific gravity were significantly higher in female, while wall thickness and vessel element length were higher in male clones. Female parents (G48 and S7C8) showed higher flber length and specific gravity than of the male parent (G3), while vessel diameter and wall thickness were higher in male par- ent (G3). There is not much difference in fiber length and vessel ele- ment's dimensions among the parents, F1 and F2 generation hybrid clones. Specific gravity did not showed any trend for parents, F1 and F2 generations. Generally female clones showed higher growth rate. Broad sense heritability for wood traits ranged from 0.143 (fiber length) to 0.505 (fiber wall thickness), while for growth Waits it was 0.374 (GBH) and 0.418 (height). Genetic gain for all the wood and growth traits was positive for most of the wood waits. The highly divergent male clone (78) and female clones (S7C8, G48, W/A 49) in number of combinations could be used for developing new hybrids of desired wood traits to de- velop new clones.

  15. Photo-Patternable ZnO Thin Films Based on Cross-Linked Zinc Acrylate for Organic/Inorganic Hybrid Complementary Inverters.

    Science.gov (United States)

    Jeong, Yong Jin; An, Tae Kyu; Yun, Dong-Jin; Kim, Lae Ho; Park, Seonuk; Kim, Yebyeol; Nam, Sooji; Lee, Keun Hyung; Kim, Se Hyun; Jang, Jaeyoung; Park, Chan Eon

    2016-03-02

    Complementary inverters consisting of p-type organic and n-type metal oxide semiconductors have received considerable attention as key elements for realizing low-cost and large-area future electronics. Solution-processed ZnO thin-film transistors (TFTs) have great potential for use in hybrid complementary inverters as n-type load transistors because of the low cost of their fabrication process and natural abundance of active materials. The integration of a single ZnO TFT into an inverter requires the development of a simple patterning method as an alternative to conventional time-consuming and complicated photolithography techniques. In this study, we used a photocurable polymer precursor, zinc acrylate (or zinc diacrylate, ZDA), to conveniently fabricate photopatternable ZnO thin films for use as the active layers of n-type ZnO TFTs. UV-irradiated ZDA thin films became insoluble in developing solvent as the acrylate moiety photo-cross-linked; therefore, we were able to successfully photopattern solution-processed ZDA thin films using UV light. We studied the effects of addition of a tiny amount of indium dopant on the transistor characteristics of the photopatterned ZnO thin films and demonstrated low-voltage operation of the ZnO TFTs within ±3 V by utilizing Al2O3/TiO2 laminate thin films or ion-gels as gate dielectrics. By combining the ZnO TFTs with p-type pentacene TFTs, we successfully fabricated organic/inorganic hybrid complementary inverters using solution-processed and photopatterned ZnO TFTs.

  16. The Effects of Land Use Patterns on Tour Type Choice. The Application of a Hybrid Choice Model

    DEFF Research Database (Denmark)

    de Abreu e Silva, João; Sottile, Eleonora; Cherchi, Elisabetta

    2014-01-01

    to travel. Workers who reside in more central, mixed and traditional urban spaces tend to have a higher propensity to travel. Workers who live in more diverse areas have a higher probability of engaging in more complex work related tours. Working in more suburban areas reduces the probability of engaging......The relations between travel behavior and land use patterns have been the object of intensive research in the last two decades. Due to their immediate policy implications, mode choice and vehicle miles of travel (VMT) have been the main focus of attention. Other relevant dimensions, like trip...... of the latent propensity to travel in the discrete choice among types of tours. This model is applied to a travel diary of workers collected in the Lisbon Metropolitan Area in 2009. Different model specifications were built, testing the inclusion of purportedly built land use factors, which have the advantage...

  17. Spoof Plasmon Hybridization

    CERN Document Server

    Zhang, Jingjing; Luo, Yu; Shen, Xiaopeng; Maier, Stefan A; Cui, Tie Jun

    2016-01-01

    Plasmon hybridization between closely spaced nanoparticles yields new hybrid modes not found in individual constituents, allowing for the engineering of resonance properties and field enhancement capabilities of metallic nanostructure. Experimental verifications of plasmon hybridization have been thus far mostly limited to optical frequencies, as metals cannot support surface plasmons at longer wavelengths. Here, we introduce the concept of 'spoof plasmon hybridization' in highly conductive metal structures and investigate experimentally the interaction of localized surface plasmon resonances (LSPR) in adjacent metal disks corrugated with subwavelength spiral patterns. We show that the hybridization results in the splitting of spoof plasmon modes into bonding and antibonding resonances analogous to molecular orbital rule and plasmonic hybridization in optical spectrum. These hybrid modes can be manipulated to produce enormous field enhancements (larger than 5000) by tuning the separation between disks or alte...

  18. Nanoscale Deformable Optics

    Science.gov (United States)

    Strauss, Karl F.; Sheldon, Douglas J.

    2011-01-01

    Several missions and instruments in the conceptual design phase rely on the technique of interferometry to create detectable fringe patterns. The intimate emplacement of reflective material upon electron device cells based upon chalcogenide material technology permits high-speed, predictable deformation of the reflective surface to a subnanometer or finer resolution with a very high degree of accuracy. In this innovation, a layer of reflective material is deposited upon a wafer containing (perhaps in the millions) chalcogenic memory cells with the reflective material becoming the front surface of a mirror and the chalcogenic material becoming a means of selectively deforming the mirror by the application of heat to the chalcogenic material. By doing so, the mirror surface can deform anywhere from nil to nanometers in spots the size of a modern day memory cell, thereby permitting realtime tuning of mirror focus and reflectivity to mitigate aberrations caused elsewhere in the optical system. Modern foundry methods permit the design and manufacture of individual memory cells having an area of or equal to the Feature (F) size of the design (assume 65 nm). Fabrication rules and restraints generally require the instantiation of one memory cell to another no closer than 1.5 F, or, for this innovation, 90 nm from its neighbor in any direction. Chalcogenide is a semiconducting glass compound consisting of a combination of chalcogen ions, the ratios of which vary according to properties desired. It has been shown that the application of heat to cells of chalcogenic material cause a large alteration in resistance to the range of 4 orders of magnitude. It is this effect upon which chalcogenidebased commercial memories rely. Upon removal of the heat source, the chalcogenide rapidly cools and remains frozen in the excited state. It has also been shown that the chalcogenide expands in volume because of the applied heat, meaning that the coefficient of expansion of chalcogenic

  19. Nanoscale Electronic Devices

    Science.gov (United States)

    Jing, Xiaoye

    Continuous downscaling in microelectronics has pushed conventional CMOS technology to its physical limits, while Moore's Law has correctly predicted the trend for decades, each step forward is accompanied with unprecedented technological difficulties and near-exponential increase in cost. At the same time, however, demands for low-power, low-cost and high-speed devices have never diminished, instead, even more stringent requirements have been imposed on device performances. It is therefore crucial to explore alternative materials and device architectures in order to alleviate the pressure caused by downscaling. To this end, we investigated two different approaches: (1) InSb nanowire based field effect transistors (NWFETs) and (2) single walled carbon nanotube (SWCNT) -- peptide nucleic acid (PNA) --SWCNT conjugate. Two types of InSb nanowires were synthesized by template-assisted electrochemistry and chemical vapor deposition (CVD) respectively. In both cases, NWFETs were fabricated by electron beam lithography (EBL) and crystallinity was confirmed by transmission electron microscopy (TEM) and selected area diffraction (SAD) patterns. For electrochemistry nanowire, ambipolar conduction was observed with strong p-type conduction, the effect of thermal annealing on the conductivity was analyzed, a NWFET model that took into consideration the underlapped region in top-gated NWFET was proposed. Hole mobility in the channel was calculated to be 292.84 cm2V-1s -1 with a density of 1.5x1017/cm3. For CVD nanowire, the diameter was below 40nm with an average of 20nm. Vapor-liquid-solid (VLS) process was speculated to be the mechanism responsible for nanowire growth. The efficient gate control was manifested by high ION/I OFF ratio which was on the order of 106 and a small inverse subthreshold slope (<200 mV/decade). Scale analysis was used to successfully account for disparities observed among a number of sample devices. N-type conduction was found in all NWFETs with

  20. Design, fabrication, and operation of hybrid bionanodevices for biomedical applications

    Science.gov (United States)

    Tucker, Robert Matthew

    Cells are the fundamental building blocks of life. Despite their simplicity, cells are extremely versatile, performing a variety of functions including detection, signaling, and repair. While current biomedical devices operate at the organ level, the next generation will operate at the cellular level, combining the nanoscale machinery of cells with the mechanical robustness of synthetic materials in the form of new hybrid devices. This thesis presents advances in four topics concerning the development of nanomedical devices: fabrication, stabilization, control, and operation. First, as feature sizes decrease from the milli- and microscale towards the nanoscale, new fabrication methods must be developed. A new rapid prototyping technique using confocal microscopy was used to produce freely-programmable high-resolution protein patterns of functional motor proteins on thermo-responsive polymer surfaces. Second, hybrid device operation should be temperature-independent, but most biological components have strong responses to temperature fluctuations. To counter operational fluctuations, the temperature-dependent enzymatic activity was characterized for two types of molecular motors with the goal of developing a bionanosystem which is stabilized against temperature fluctuations. Third, replacing electromechanical systems consisting of pumps and batteries with proteins that directly convert chemical potential into mechanical energy increases the efficiency and decreases the size of the bionanodevice, but requires new control methods. An enzymatic network was developed in which fuel was photolytically released to activate molecular shuttles, excess fuel was sequestered using an enzyme, and spatial and temporal control of the system was achieved. Finally, chemically powered bionanodevices will require high-precision nano- and microscale actuators. A two-part hybrid actuator was designed, which consists of a molecular motor-coated synthetic macroscale forcer and a

  1. Center for Nanoscale Science and Technology

    Science.gov (United States)

    NIST Center for Nanoscale Science and Technology (Program website, free access)   Currently there is no database matching your keyword search, but the NIST Center for Nanoscale Science and Technology website may be of interest. The Center for Nanoscale Science and Technology enables science and industry by providing essential measurement methods, instrumentation, and standards to support all phases of nanotechnology development, from discovery to production.

  2. New secure bilateral transaction determination and study of pattern under contingencies and UPFC in competitive hybrid electricity markets

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.; Chanana, S. [Department of Electrical Engineering, National Institute of Technology, Kurukshetra 136119 (India)

    2009-01-15

    In the competitive electricity environment, the flexibility of power transactions is expected to drastically increase among the trading partners and can compromise the system security and reliability. These transactions are to be evaluated ahead of their scheduling in a day-ahead and hour-ahead market to avoid congestion and ensure their feasibility with respect to the system operating conditions. The security of the transactions has become essential in the new environment for better planning and management of competitive electricity markets. This paper proposes a new method of secure bilateral transaction determination using AC distribution factors based on the full Jacobian sensitivity and considering the impact of slack bus for pool and bilateral coordinated markets. The secure bilateral transactions have also been determined considering critical line outage contingencies cases. The bilateral transaction matrix pattern has also been determined in the presence of unified power flow controller (UPFC). The optimal location of UPFC has been determined using mixed integer non-linear programming approach. The proposed technique has been applied on IEEE 24-bus reliability test system (RTS). (author)

  3. Quantifying dissipative contributions in nanoscale interactions.

    Science.gov (United States)

    Santos, Sergio; Gadelrab, Karim R; Souier, Tewfik; Stefancich, Marco; Chiesa, Matteo

    2012-02-01

    Imaging with nanoscale resolution has become routine practice with the use of scanning probe techniques. Nevertheless, quantification of material properties and processes has been hampered by the complexity of the tip-surface interaction and the dependency of the dynamics on operational parameters. Here, we propose a framework for the quantification of the coefficients of viscoelasticity, surface energy, surface energy hysteresis and elastic modulus. Quantification of these parameters at the nanoscale will provide a firm ground to the understanding and modelling of tribology and nanoscale sciences with true nanoscale resolution.

  4. Fine grain tungsten produced with nanoscale powder

    Institute of Scientific and Technical Information of China (English)

    Tao Lin; Fang Zhao; Liying Zhang; Chengyi Wu; Zhimeng Guo

    2005-01-01

    Nanoscale tungsten powder was prepared by reducing nanoscale tungsten trioxide in hydrogen to WO2.90 and further to W powder. After compacted with a rubber die, the nanoscale tungsten powder was sintered in a high-temperature dilatometer to investigate its shrinkage process. The results show that the compact of the nanoscale tungsten powder starts to shrink at 1050℃ and ends at 1500℃. The shrinkage rate reaches the maximum value at 1210℃. The relative density of sintered samples is 96.4%, and its grain size is about 5.8 μm.

  5. Ionic-Liquid-Tethered Nanoparticles: Hybrid Electrolytes

    KAUST Repository

    Moganty, Surya S.

    2010-10-22

    A new class of solventless electrolytes was created by tethering ionic liquids to hard inorganic ZrO2 nanostructures (see picture; NIM=nanoscale ionic material). These hybrid fluids exhibit exceptional redox stability windows, excellent thermal stability, good lithium transference numbers, long-term interfacial stability in the presence of a lithium anode and, when doped with lithium salt, reasonable ionic conductivities.

  6. Adhesion Dynamics in Probing Micro- and Nanoscale Thin Solid Films

    Directory of Open Access Journals (Sweden)

    Xiaoling He

    2008-01-01

    Full Text Available This study focuses on modeling the probe dynamics in scratching and indenting thin solid films at micro- and nanoscales. The model identifies bifurcation conditions that define the stick-slip oscillation patterns of the tip. It is found that the local energy fluctuations as a function of the inelastic deformation, defect formation, material properties, and contact parameters determine the oscillation behavior. The transient variation of the localized function makes the response nonlinear at the adhesion junction. By quantifying the relation between the bifurcation parameters and the oscillation behavior, this model gives a realistic representation of the complex adhesion dynamics. Specifically, the model establishes the link between the stick-slip behavior and the inelastic deformation and the local potentials. This model justifies the experimental observations and the molecular dynamics simulation of the adhesion and friction dynamics in both the micro- and nanoscale contact.

  7. Strategies for Controlled Placement of Nanoscale Building Blocks

    Directory of Open Access Journals (Sweden)

    Koh SeongJin

    2007-01-01

    Full Text Available AbstractThe capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others.

  8. Nanoscale synthesis and characterization of graphene-based objects

    Directory of Open Access Journals (Sweden)

    Daisuke Fujita

    2011-01-01

    Full Text Available Graphene-based nano-objects such as nanotrenches, nanowires, nanobelts and nanoscale superstructures have been grown by surface segregation and precipitation on carbon-doped mono- and polycrystalline nickel substrates in ultrahigh vacuum. The dominant morphologies of the nano-objects were nanowire and nanosheet. Nucleation of graphene sheets occurred at surface defects such as step edges and resulted in the directional growth of nanowires. Surface analysis by scanning tunneling microscopy (STM has clarified the structure and functionality of the novel nano-objects at atomic resolution. Nanobelts were detected consisting of bilayer graphene sheets with a nanoscale width and a length of several microns. Moiré patterns and one-dimensional reconstruction were observed on multilayer graphite terraces. As a useful functionality, application to repairable high-resolution STM probes is demonstrated.

  9. Nanoscale chemical imaging by photoinduced force microscopy

    Science.gov (United States)

    Nowak, Derek; Morrison, William; Wickramasinghe, H. Kumar; Jahng, Junghoon; Potma, Eric; Wan, Lei; Ruiz, Ricardo; Albrecht, Thomas R.; Schmidt, Kristin; Frommer, Jane; Sanders, Daniel P.; Park, Sung

    2016-01-01

    Correlating spatial chemical information with the morphology of closely packed nanostructures remains a challenge for the scientific community. For example, supramolecular self-assembly, which provides a powerful and low-cost way to create nanoscale patterns and engineered nanostructures, is not easily interrogated in real space via existing nondestructive techniques based on optics or electrons. A novel scanning probe technique called infrared photoinduced force microscopy (IR PiFM) directly measures the photoinduced polarizability of the sample in the near field by detecting the time-integrated force between the tip and the sample. By imaging at multiple IR wavelengths corresponding to absorption peaks of different chemical species, PiFM has demonstrated the ability to spatially map nm-scale patterns of the individual chemical components of two different types of self-assembled block copolymer films. With chemical-specific nanometer-scale imaging, PiFM provides a powerful new analytical method for deepening our understanding of nanomaterials. PMID:27051870

  10. Analysis of gene expression patterns by microarray hybridization in blood mononuclear cells of SLA-DRB1 defined Canadian Yorkshire pigs.

    Science.gov (United States)

    Nino-Soto, Maria I; Jozani, Razi Jafari; Bridle, Byram; Mallard, Bonnie A

    2008-06-23

    The Swine Leukocyte Antigen (SLA) system encodes molecules for self-nonself discrimination and is associated with immune responses and disease resistance. Three lines of pigs defined by their SLA-DRB1 alleles were developed at the University of Guelph for xenotransplantation and immune response studies. The aim of this project was to explore the potential association between defined SLA-DRB1 alleles and gene transcriptional patterns of other immune-related genes in blood mononuclear cells. Three SLA-DRB1 alleles were characterized using a RT-PCR-based sequencing method. The loci represented included a new allele, DRB1*04ns01. Next, microarray heterologous (bovine-porcine) hybridization together with qPCR were used to explore differential gene expression between SLA-DRB1-defined groups. Microarray analysis showed significant (p SLA-DRB1 allele was characterized. A potential association was found between SLA-DRB1 alleles and inflammation-related genes. However, the influence of other genes cannot be ruled out. These preliminary findings agree with other studies linking MHC haplotypes and inflammation processes, including autoimmune disease. The study provides an initial view of the biological interactions between the SLA complex and other immune-related genes. Future studies will focus on characterization of SLA-haplotypes associated with these particular alleles and the dynamics of the immune response to antigenic challenges.

  11. Nanoscale Engineering of Multiferroic Hybrid Composites for Micro- and Nano-scale Devices

    Science.gov (United States)

    2012-09-14

    electric signal stimulation of living cells", Leszek Malkinski and Armin Kargol (Loyola University) (2010). Presentations: 2009-2012 1) Shiva Adireddy...MRS Spring Meeting, April 5-9, 2010, San Francisco, CA. 6) Gabriel Caruntu, Amin Yourdkhani, Armando K. Perez, Shiva Adireddy "Soft Solution...2010. 12) Gabriel Caruntu, Amin Yourdkhani, Armando K. Perez, Shiva Adireddy "Soft Solution Processing of Ferroelectric Nanostructures and Their

  12. Nanoscale Magnetic Materials for Energy-Efficient Spin Based Transistors

    Science.gov (United States)

    Incorvia, Jean Anne Currivan

    In this dissertation, I study the physical behavior of nanoscale magnetic materials and build spin-based transistors that encode information in magnetic domain walls. It can be argued that energy dissipation is the most serious problem in modern electronics, and one that has been resistant to a breakthrough. Wasted heat during computing both wastes energy and hinders further technology scaling. This is an opportunity for physicists and engineers to come up with creative solutions for more energy-efficient computing. I present the device we have designed, called domain wall logic (DW-Logic). Information is stored in the position of a magnetic domain wall in a ferromagnetic wire and read out using a magnetic tunnel junction. This hybrid design uses electrical current as the input and output, keeping the device compatible with charge- based transistors. I build an iterative model to predict both the micromagnetic and circuit behavior of DW- Logic, showing a single device can operate as a universal gate. The model shows we can build complex circuits including an 18-gate Full Adder, and allows us to predict the device switching energy compared to complementary metal-oxide semiconductor (CMOS) transistors. Comparing ?15 nm feature nodes, I find DW-Logic made with perpendicular magnetic anisotropy materials, and utilizing both spin torque transfer and the Spin Hall effect, could operate with 1000x reduced switching energy compared to CMOS. I fabricate DW-Logic device prototypes and show in experiment they can act as AND and NAND gates. I demonstrate that one device can drive two subsequent devices, showing gain, which is a necessary requirement for fanout. I also build a clocked ring oscillator circuit to demonstrate successful bit propagation in a DW-Logic circuit and show that properly scaled devices can have improved operation. Through building the devices, I develop a novel fabrication method for patterning sub-25 nm magnetic wires with very low (˜ 2 nm) average edge

  13. Nanoscale Properties of Boric Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanoscale properties of boric acid were studied by using atomic force microscopy (AFM) and nanome-chanical testing system. XPS was used to research on the transform behaviors of H3BO3 at different temperatures.The crystal structure, surface morphology, and mechanical properties of H3BO3 were described. The results showthat H3BO3 has layered structure, and can be transformed to boron oxide at high temperature. In addition there area lot of defects in H3BO3 crystal.

  14. Synthesis of nanoscale antimony particles

    Energy Technology Data Exchange (ETDEWEB)

    Balan, L.; Dailly, A. [Universite Henri Poincare Nancy I, Laboratoire de Chimie du Solide Mineral, UMR 7555 CNRS (France); Schneider, R. [Universite Henri Poincare Nancy I, Laboratoire de Synthese organometallique et Reactivite, UMR 7565 CNRS (France); Billaud, D., E-mail: Denis.Billaud@lcsm.uhp-nancy.fr [Universite Henri Poincare Nancy I, Laboratoire de Chimie du Solide Mineral, UMR 7555 CNRS (France); Willmann, P. [Centre National d' Etudes Spatiales, (France); Olivier-Fourcade, J.; Jumas, J.-C. [Universite Montpellier, Laboratoire des Agregats Moleculaires et Materiaux Inorganiques, UMR 5072 CNRS (France)

    2005-09-15

    For the search of new negative electrodes of Li-ion batteries, a low-temperature method has been developed for the preparation of nanoscale antimony particles which uses an alkoxide-activated sodium hydride as reducing agent of antimony pentachloride. X-ray diffraction and TEM studies confirm the obtaining of amorphous Sb nanoparticles dispersed in an organic matrix. {sup 121}Sb Moessbauer spectroscopy gives evidence for the occurrence of interactions between antimony and the matrix. These interactions are modified by the washing treatments.

  15. Spin manipulation in nanoscale superconductors.

    Science.gov (United States)

    Beckmann, D

    2016-04-27

    The interplay of superconductivity and magnetism in nanoscale structures has attracted considerable attention in recent years due to the exciting new physics created by the competition of these antagonistic ordering phenomena, and the prospect of exploiting this competition for superconducting spintronics devices. While much of the attention is focused on spin-polarized supercurrents created by the triplet proximity effect, the recent discovery of long range quasiparticle spin transport in high-field superconductors has rekindled interest in spin-dependent nonequilibrium properties of superconductors. In this review, the experimental situation on nonequilibrium spin injection into superconductors is discussed, and open questions and possible future directions of the field are outlined.

  16. Surface Chemistry in Nanoscale Materials

    Directory of Open Access Journals (Sweden)

    Alex V. Hamza

    2009-12-01

    Full Text Available Although surfaces or, more precisely, the surface atomic and electronic structure, determine the way materials interact with their environment, the influence of surface chemistry on the bulk of the material is generally considered to be small. However, in the case of high surface area materials such as nanoporous solids, surface properties can start to dominate the overall material behavior. This allows one to create new materials with physical and chemical properties that are no longer determined by the bulk material, but by their nanoscale architectures. Here, we discuss several examples, ranging from nanoporous gold to surface engineered carbon aerogels that demonstrate the tuneability of nanoporous solids for sustainable energy applications.

  17. Electron turbulence at nanoscale junctions.

    Science.gov (United States)

    Bushong, Neil; Gamble, John; Di Ventra, Massimiliano

    2007-06-01

    Electron transport through a nanostructure can be characterized in part using concepts from classical fluid dynamics. It is thus natural to ask how far the analogy can be taken and whether the electron liquid can exhibit nonlinear dynamical effects such as turbulence. Here we present an ab initio study of the electron dynamics in nanojunctions which reveals that the latter indeed exhibits behavior quite similar to that of a classical fluid. In particular, we find that a transition from laminar to turbulent flow occurs with increasing current, corresponding to increasing Reynolds numbers. These results reveal unexpected features of electron dynamics and shed new light on our understanding of transport properties of nanoscale systems.

  18. Nanoscale tomography in materials science

    Directory of Open Access Journals (Sweden)

    Günter Möbus

    2007-12-01

    Full Text Available In materials science, various techniques for three-dimensional reconstruction of microstructures have been applied successfully for decades, such as X-ray tomography and mechanical sectioning. However, in the last decade the family tree of methods has grown significantly. This is partly through advances in instrumentation. The introduction of the focused ion beam microscope and the transformation of transmission electron microscopy into a multipurpose analytical and structural tool have made major impacts. The main driving force for progress is perhaps the advent of nanotechnology with the need to achieve nanometer-scale resolution and the desire to get a real three-dimensional view of the nanoscale world.

  19. Patterning Luminescent Nanocrystalline LaPO4 : Eu and CePO4 : Tb Particles Embedded in Hybrid Organosilica with Soft-Lithographic Techniques

    Directory of Open Access Journals (Sweden)

    Sajid U. Khan

    2012-01-01

    Full Text Available Eu3+-doped LaPO4 and Tb3+-doped CePO4 luminescent nanoparticles embedded in hybrid organosilica were patterned by two soft lithographic techniques. The role of various parameters such as solution chemistry, thermal protocols, and modification of the mold-substrate surface energies related to pattern shape formation and adhesion to the substrates have been studied. The shrinkage of the oxide patterns and shape evolution during the process was also examined. The patterns were characterized with optical and photoluminescence (PL microscopy, X-ray diffraction (XRD, and scanning electron microscopy (SEM. Compositional analyses were carried out with X-ray photoelectron spectroscopy (XPS, low-energy ion scattering (LEIS, and secondary ion mass spectroscopy (SIMS. The results indicated that the final patterns obtained with these two techniques for the same material have different shapes and adherence to the substrates.

  20. Reliable passivation of black phosphorus by thin hybrid coating

    Science.gov (United States)

    Gamage, S.; Fali, A.; Aghamiri, N.; Yang, L.; Ye, P. D.; Abate, Y.

    2017-06-01

    Black phosphorus (BP) possesses several extraordinary physical properties, which include in-plane anisotropy, thickness dependent direct bandgap and high carrier mobility. These physical properties make BP highly desirable from the point of view of fundamental science and modern optoelectronics applications. The excitement about this material has always been accompanied by unreserved skepticism due to its extraordinary degradation under ambient conditions. Here we show ambient degradation of exfoliated BP can be effectively suppressed using thin layer of hybrid metal organic chemical vapor deposition coating of boron nitride (BN) followed by atomic layer deposition coating of Al2O3. We have extensively studied the time dependent surface, optical and electrical properties of BP encapsulated by BN and/or Al2O3 using nanoscale infrared imaging and I-V characterizations. Our results show hybrid thin layer (˜5 nm) BN/Al2O3 coated BP exfoliated on SiO2 substrate is protected from degradation in ambient for over 6 months, much longer than those coated only by BN or Al2O3 layers. Our theoretical modeling of the experimental degradation growth pattern shows that the influence of neighboring elements on the degradation of a given element is minimal for BP flakes with hybrid coating. Electrical characterization further confirms the effectiveness of BN/Al2O3 as encapsulation layer and gate dielectrics with minor changes after several weeks.

  1. Properties of nanoscale metal hydrides.

    Science.gov (United States)

    Fichtner, Maximilian

    2009-05-20

    Nanoscale hydride particles may exhibit chemical stabilities which differ from those of a macroscopic system. The stabilities are mainly influenced by a surface energy term which contains size-dependent values of the surface tension, the molar volume and an additional term which takes into account a potential reduction of the excess surface energy. Thus, the equilibrium of a nanoparticular hydride system may be shifted to the hydrogenated or to the dehydrogenated side, depending on the size and on the prefix of the surface energy term of the hydrogenated and dehydrogenated material. Additional complexity appears when solid-state reactions of complex hydrides are considered and phase segregation has to be taken into account. In such a case the reversibility of complex hydrides may be reduced if the nanoparticles are free standing on a surface. However, it may be enhanced if the system is enclosed by a nanoscale void which prevents the reaction partners on the dehydrogenated side from diffusing away from each other. Moreover, the generally enhanced diffusivity in nanocrystalline systems may lower the kinetic barriers for the material's transformation and, thus, facilitate hydrogen absorption and desorption.

  2. Maximal Heat Generation in Nanoscale Systems

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Ling; LI Shu-Shen; ZENG Zhao-Yang

    2009-01-01

    We investigate the heat generation in a nanoscale system coupled to normal leads and find that it is maximal when the average occupation of the electrons in the nanoscale system is 0.5,no matter what mechanism induces the heat generation.

  3. Chaotic mixer improves microarray hybridization.

    Science.gov (United States)

    McQuain, Mark K; Seale, Kevin; Peek, Joel; Fisher, Timothy S; Levy, Shawn; Stremler, Mark A; Haselton, Frederick R

    2004-02-15

    Hybridization is an important aspect of microarray experimental design which influences array signal levels and the repeatability of data within an array and across different arrays. Current methods typically require 24h and use target inefficiently. In these studies, we compare hybridization signals obtained in conventional static hybridization, which depends on diffusional target delivery, with signals obtained in a dynamic hybridization chamber, which employs a fluid mixer based on chaotic advection theory to deliver targets across a conventional glass slide array. Microarrays were printed with a pattern of 102 identical probe spots containing a 65-mer oligonucleotide capture probe. Hybridization of a 725-bp fluorescently labeled target was used to measure average target hybridization levels, local signal-to-noise ratios, and array hybridization uniformity. Dynamic hybridization for 1h with 1 or 10ng of target DNA increased hybridization signal intensities approximately threefold over a 24-h static hybridization. Similarly, a 10- or 60-min dynamic hybridization of 10ng of target DNA increased hybridization signal intensities fourfold over a 24h static hybridization. In time course studies, static hybridization reached a maximum within 8 to 12h using either 1 or 10ng of target. In time course studies using the dynamic hybridization chamber, hybridization using 1ng of target increased to a maximum at 4h and that using 10ng of target did not vary over the time points tested. In comparison to static hybridization, dynamic hybridization reduced the signal-to-noise ratios threefold and reduced spot-to-spot variation twofold. Therefore, we conclude that dynamic hybridization based on a chaotic mixer design improves both the speed of hybridization and the maximum level of hybridization while increasing signal-to-noise ratios and reducing spot-to-spot variation.

  4. Thermochemical scanning probe lithography of protein gradients at the nanoscale

    Science.gov (United States)

    Albisetti, E.; Carroll, K. M.; Lu, X.; Curtis, J. E.; Petti, D.; Bertacco, R.; Riedo, E.

    2016-08-01

    Patterning nanoscale protein gradients is crucial for studying a variety of cellular processes in vitro. Despite the recent development in nano-fabrication technology, combining nanometric resolution and fine control of protein concentrations is still an open challenge. Here, we demonstrate the use of thermochemical scanning probe lithography (tc-SPL) for defining micro- and nano-sized patterns with precisely controlled protein concentration. First, tc-SPL is performed by scanning a heatable atomic force microscopy tip on a polymeric substrate, for locally exposing reactive amino groups on the surface, then the substrate is functionalized with streptavidin and laminin proteins. We show, by fluorescence microscopy on the patterned gradients, that it is possible to precisely tune the concentration of the immobilized proteins by varying the patterning parameters during tc-SPL. This paves the way to the use of tc-SPL for defining protein gradients at the nanoscale, to be used as chemical cues e.g. for studying and regulating cellular processes in vitro.

  5. Formation and Characterization of Stacked Nanoscale Layers of Polymers and Silanes on Silicon Surfaces

    Science.gov (United States)

    Ochoa, Rosie; Davis, Brian; Conley, Hiram; Hurd, Katie; Linford, Matthew R.; Davis, Robert C.

    2008-10-01

    Chemical surface patterning at the nanoscale is a critical component of chemically directed assembly of nanoscale devices or sensitive biological molecules onto surfaces. Complete and consistent formation of nanoscale layers of silanes and polymers is a necessary first step for chemical patterning. We explored methods of silanizing silicon substrates for the purpose of functionalizing the surfaces. The chemical functionalization, stability, flatness, and repeatability of the process was characterized by use of ellipsometry, water contact angle, and Atomic Force Microscopy (AFM). We found that forming the highest quality functionalized surfaces was accomplished through use of chemical vapor deposition (CVD). Specifically, surfaces were plasma cleaned and hydrolyzed before the silane was applied. A polymer layer less then 2 nm in thickness was electrostatically bound to the silane layer. The chemical functionalization, stability, flatness, and repeatability of the process was also characterized for the polymer layer using ellipsometry, water contact angle, and AFM.

  6. Microarray analysis of gene expression patterns in the leaf during potato tuberization in the potato somatic hybrid Solanum tuberosum and Solanum etuberosum.

    Science.gov (United States)

    Tiwari, Jagesh Kumar; Devi, Sapna; Sundaresha, S; Chandel, Poonam; Ali, Nilofer; Singh, Brajesh; Bhardwaj, Vinay; Singh, Bir Pal

    2015-06-01

    Genes involved in photoassimilate partitioning and changes in hormonal balance are important for potato tuberization. In the present study, we investigated gene expression patterns in the tuber-bearing potato somatic hybrid (E1-3) and control non-tuberous wild species Solanum etuberosum (Etb) by microarray. Plants were grown under controlled conditions and leaves were collected at eight tuber developmental stages for microarray analysis. A t-test analysis identified a total of 468 genes (94 up-regulated and 374 down-regulated) that were statistically significant (p ≤ 0.05) and differentially expressed in E1-3 and Etb. Gene Ontology (GO) characterization of the 468 genes revealed that 145 were annotated and 323 were of unknown function. Further, these 145 genes were grouped based on GO biological processes followed by molecular function and (or) PGSC description into 15 gene sets, namely (1) transport, (2) metabolic process, (3) biological process, (4) photosynthesis, (5) oxidation-reduction, (6) transcription, (7) translation, (8) binding, (9) protein phosphorylation, (10) protein folding, (11) ubiquitin-dependent protein catabolic process, (12) RNA processing, (13) negative regulation of protein, (14) methylation, and (15) mitosis. RT-PCR analysis of 10 selected highly significant genes (p ≤ 0.01) confirmed the microarray results. Overall, we show that candidate genes induced in leaves of E1-3 were implicated in tuberization processes such as transport, carbohydrate metabolism, phytohormones, and transcription/translation/binding functions. Hence, our results provide an insight into the candidate genes induced in leaf tissues during tuberization in E1-3.

  7. Optical tuning of near and far fields form hybrid dimer nanoantennas via laser-induced melting

    Science.gov (United States)

    Kolodny, Stanislav A.; Sun, Yali; Zuev, Dmitry A.; Makarov, Sergey V.; Krasnok, Alexander E.; Belov, Pavel A.

    2016-08-01

    Hybrid nanophotonics based on metal-dielectric nanostructures unifies the advantages of plasmonics and all-dielectric nanophotonics providing strong localization of light, magnetic optical response and specifically designed scattering properties. Here, we propose a new method for optical properties tuning of hybrid dimer nanoantenas via laser-induced melting at the nanoscale. We demonstrate numerically that near- and farfield properties of a hybrid nanoantenna dramatically changes with fs-laser modification of Au particle. The results lay the groundwork for the fine-tuning of hybrid nanoantennas and can be applied for effective light manipulation at the nanoscale, as well as biomedical and energy applications.

  8. Design exploration of emerging nano-scale non-volatile memory

    CERN Document Server

    Yu, Hao

    2014-01-01

    This book presents the latest techniques for characterization, modeling and design for nano-scale non-volatile memory (NVM) devices.  Coverage focuses on fundamental NVM device fabrication and characterization, internal state identification of memristic dynamics with physics modeling, NVM circuit design, and hybrid NVM memory system design-space optimization. The authors discuss design methodologies for nano-scale NVM devices from a circuits/systems perspective, including the general foundations for the fundamental memristic dynamics in NVM devices.  Coverage includes physical modeling, as well as the development of a platform to explore novel hybrid CMOS and NVM circuit and system design.   • Offers readers a systematic and comprehensive treatment of emerging nano-scale non-volatile memory (NVM) devices; • Focuses on the internal state of NVM memristic dynamics, novel NVM readout and memory cell circuit design, and hybrid NVM memory system optimization; • Provides both theoretical analysis and pr...

  9. Attosecond physics at the nanoscale

    CERN Document Server

    Ciappina, M F; Landsman, A S; Okell, W; Zherebtsov, S; Förg, B; Schötz, J; Seiffert, J L; Fennel, T; Shaaran, T; Zimmermann, T; Chacón, A; Guichard, R; Zaïr, A; Tisch, J W G; Marangos, J P; Witting, T; Braun, A; Maier, S A; Roso, L; Krüger, M; Hommelhoff, P; Kling, M F; Krausz, F; Lewenstein, M

    2016-01-01

    Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds, which is comparable with the optical field. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this article we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spati...

  10. Nanoscale materials for hyperthermal theranostics.

    Science.gov (United States)

    Smith, Bennett E; Roder, Paden B; Zhou, Xuezhe; Pauzauskie, Peter J

    2015-04-28

    Recently, the use of nanoscale materials has attracted considerable attention with the aim of designing personalized therapeutic approaches that can enhance both spatial and temporal control over drug release, permeability, and uptake. Potential benefits to patients include the reduction of overall drug dosages, enabling the parallel delivery of different pharmaceuticals, and the possibility of enabling additional functionalities such as hyperthermia or deep-tissue imaging (LIF, PET, etc.) that complement and extend the efficacy of traditional chemotherapy and surgery. This mini-review is focused on an emerging class of nanometer-scale materials that can be used both to heat malignant tissue to reduce angiogenesis and DNA-repair while simultaneously offering complementary imaging capabilities based on radioemission, optical fluorescence, magnetic resonance, and photoacoustic methods.

  11. Optical Spectroscopy at the Nanoscale

    Science.gov (United States)

    Hong, Xiaoping

    Recent advances in material science and fabrication techniques enabled development of nanoscale applications and devices with superior performances and high degree of integration. Exotic physics also emerges at nanoscale where confinement of electrons and phonons leads to drastically different behavior from those in the bulk materials. It is therefore rewarding and interesting to investigate and understand material properties at the nanoscale. Optical spectroscopy, one of the most versatile techniques for studying material properties and light-matter interactions, can provide new insights into the nanomaterials. In this thesis, I explore advanced laser spectroscopic techniques to probe a variety of different nanoscale phenomena. A powerful tool in nanoscience and engineering is scanning tunneling microscopy (STM). Its capability in atomic resolution imaging and spectroscopy unveiled the mystical quantum world of atoms and molecules. However identification of molecular species under investigation is one of the limiting functionalities of the STM. To address this need, we take advantage of the molecular `fingerprints' - vibrational spectroscopy, by combining an infrared light sources with scanning tunneling microscopy. In order to map out sharp molecular resonances, an infrared continuous wave broadly tunable optical parametric oscillator was developed with mode-hop free fine tuning capabilities. We then combine this laser with STM by shooting the beam onto the STM substrate with sub-monolayer diamondoids deposition. Thermal expansion of the substrate is detected by the ultrasensitive tunneling current when infrared frequency is tuned across the molecular vibrational range. Molecular vibrational spectroscopy could be obtained by recording the thermal expansion as a function of the excitation wavelength. Another interesting field of the nanoscience is carbon nanotube, an ideal model of one dimensional physics and applications. Due to the small light absorption with

  12. Nanoscale metal-organic materials.

    Science.gov (United States)

    Carné, Arnau; Carbonell, Carlos; Imaz, Inhar; Maspoch, Daniel

    2011-01-01

    Metal-organic materials are found to be a fascinating novel class of functional nanomaterials. The limitless combinations between inorganic and organic building blocks enable researchers to synthesize 0- and 1-D metal-organic discrete nanostructures with varied compositions, morphologies and sizes, fabricate 2-D metal-organic thin films and membranes, and even structure them on surfaces at the nanometre length scale. In this tutorial review, the synthetic methodologies for preparing these miniaturized materials as well as their potential properties and future applications are discussed. This review wants to offer a panoramic view of this embryonic class of nanoscale materials that will be of interest to a cross-section of researchers working in chemistry, physics, medicine, nanotechnology, materials chemistry, etc., in the next years.

  13. One-Dimensional (1-D) Nanoscale Heterostructures

    Institute of Scientific and Technical Information of China (English)

    Guozhen SHEN; Di CHEN; Yoshio BANDO; Dmitri GOLBERG

    2008-01-01

    One-dimensional (1-D) nanostructures have been attracted much attention as a result of their exceptional properties, which are different from bulk materials. Among 1-D nanostructures, 1-D heterostructures with modulated compositions and interfaces have recently become of particular interest with respect to potential applications in nanoscale building blocks of future optoelectronic devices and systems. Many kinds of methods have been developed for the synthesis of 1-D nanoscale heterostructures. This article reviews the most recent development, with an emphasize on our own recent efforts, on 1-D nanoscale heterostructures, especially those synthesized from the vapor deposition methods, in which all the reactive precursors are mixed together in the reaction chamber. Three types of 1-D nanoscale heterostructures, defined from their morphologies characteristics, are discussed in detail, which include 1-D co-axial core-shell heterostructures, 1-D segmented heterostructures and hierarchical heterostructures. This article begins with a brief survey of various methods that have been developed for synthesizing 1-D nanoscale heterostructures and then mainly focuses on the synthesis, structures and properties of the above three types of nanoscale heterostructures. Finally, this review concludes with personal views towards the topic of 1-D nanoscale heterostructures.

  14. Plant virus directed fabrication of nanoscale materials and devices

    Science.gov (United States)

    2015-03-26

    TMV1cys assembled on gold-coated silicon wafers (Gerasopoulos et al., 2010). This method utilizes photoresist masks to define sacrificial layers that...microscale SU-8 polymer columns were created and assembled with TMV1cys PVNs as a mimic of the microscale bumps and nanoscale hairs found on lotus leaves...functionalized SiO2 wafers (Mueller et al., 2011) (Fig. 3E). Patterned RNAs containing the OAS were capable of guiding the bottom-up assembly of TMV-like rods

  15. Molecular and Nanoscale Engineering of High Efficiency Excitonic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Jenekhe, Samson A. [Univ. of Washington, Seattle, WA (United States); Ginger, David S. [Univ. of Washington, Seattle, WA (United States); Cao, Guozhong [Univ. of Washington, Seattle, WA (United States)

    2016-01-15

    We combined the synthesis of new polymers and organic-inorganic hybrid materials with new experimental characterization tools to investigate bulk heterojunction (BHJ) polymer solar cells and hybrid organic-inorganic solar cells during the 2007-2010 period (phase I) of this project. We showed that the bulk morphology of polymer/fullerene blend solar cells could be controlled by using either self-assembled polymer semiconductor nanowires or diblock poly(3-alkylthiophenes) as the light-absorbing and hole transport component. We developed new characterization tools in-house, including photoinduced absorption (PIA) spectroscopy, time-resolved electrostatic force microscopy (TR-EFM) and conductive and photoconductive atomic force microscopy (c-AFM and pc-AFM), and used them to investigate charge transfer and recombination dynamics in polymer/fullerene BHJ solar cells, hybrid polymer-nanocrystal (PbSe) devices, and dye-sensitized solar cells (DSSCs); we thus showed in detail how the bulk photovoltaic properties are connected to the nanoscale structure of the BHJ polymer solar cells. We created various oxide semiconductor (ZnO, TiO2) nanostructures by solution processing routes, including hierarchical aggregates and nanorods/nanotubes, and showed that the nanostructured photoanodes resulted in substantially enhanced light-harvesting and charge transport, leading to enhanced power conversion efficiency of dye-sensitized solar cells.

  16. Atom Probe Tomography of Nanoscale Electronic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Larson, David J.; Prosa, Ty J.; Perea, Daniel E.; Inoue, Hidekazu; Mangelinck, D.

    2016-01-01

    Atom probe tomography (APT) is a mass spectrometry based on time-of-flight measurements which also concurrently produces 3D spatial information. The reader is referred to any of the other papers in this volume or to the following references for further information 4–8. The current capabilities of APT, such as detecting a low number of dopant atoms in nanoscale devices or segregation at a nanoparticle interface, make this technique an important component in the nanoscale metrology toolbox. In this manuscript, we review some of the applications of APT to nanoscale electronic materials, including transistors and finFETs, silicide contact microstructures, nanowires, and nanoparticles.

  17. Symposium GC: Nanoscale Charge Transport in Excitonic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Bommisetty, Venkat [Univ. of South Dakota, Vermillion, SD (United States)

    2011-06-23

    This paper provides a summary only and table of contents of the sessions. Excitonic solar cells, including all-organic, hybrid organic-inorganic and dye-sensitized solar cells (DSSCs), offer strong potential for inexpensive and large-area solar energy conversion. Unlike traditional inorganic semiconductor solar cells, where all the charge generation and collection processes are well understood, these excitonic solar cells contain extremely disordered structures with complex interfaces which results in large variations in nanoscale electronic properties and has a strong influence on carrier generation, transport, dissociation and collection. Detailed understanding of these processes is important for fabrication of highly efficient solar cells. Efforts to improve efficiency are underway at a large number of research groups throughout the world focused on inorganic and organic semiconductors, photonics, photophysics, charge transport, nanoscience, ultrafast spectroscopy, photonics, semiconductor processing, device physics, device structures, interface structure etc. Rapid progress in this multidisciplinary area requires strong synergetic efforts among researchers from diverse backgrounds. Such effort can lead to novel methods for development of new materials with improved photon harvesting and interfacial treatments for improved carrier transport, process optimization to yield ordered nanoscale morphologies with well defined electronic structures.

  18. Advances in neuromorphic hardware exploiting emerging nanoscale devices

    CERN Document Server

    2017-01-01

    This book covers all major aspects of cutting-edge research in the field of neuromorphic hardware engineering involving emerging nanoscale devices. Special emphasis is given to leading works in hybrid low-power CMOS-Nanodevice design. The book offers readers a bidirectional (top-down and bottom-up) perspective on designing efficient bio-inspired hardware. At the nanodevice level, it focuses on various flavors of emerging resistive memory (RRAM) technology. At the algorithm level, it addresses optimized implementations of supervised and stochastic learning paradigms such as: spike-time-dependent plasticity (STDP), long-term potentiation (LTP), long-term depression (LTD), extreme learning machines (ELM) and early adoptions of restricted Boltzmann machines (RBM) to name a few. The contributions discuss system-level power/energy/parasitic trade-offs, and complex real-world applications. The book is suited for both advanced researchers and students interested in the field.

  19. Molecular dynamics simulations of nanoscale metal tips under electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Parviainen, S., E-mail: stefan.parviainen@helsinki.fi [Department of Physics and Helsinki Institute of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Djurabekova, F.; Pohjonen, A.; Nordlund, K. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland)

    2011-07-15

    Vacuum arcing is a plasma discharge over a metal surface under high electric fields. Plasma formation requires the supply of neutral atoms, which under high vacuum condition can only come from the surface itself. Nevertheless, the mechanisms by which the atoms are supplied are not known. In the present work, we propose a model for the onset of surface roughness and field-enhanced atom evaporation. Specifically, we describe a dislocation mechanism of tip growth from near-surface voids. We also simulate surface charging and resistive heating using a hybrid electrodynamics and molecular dynamics (ED and MD) code for dynamic simulations of electronic effects. We study the morphological evolution of the nanoscale protrusion under the electronic effects, such as the stretching of the tip by the stress induced by the electric field.

  20. Pure carbon nanoscale devices: Nanotube heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Chico, L.; Crespi, V.H.; Benedict, L.X.; Louie, S.G.; Cohen, M.L. [Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States)]|[Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

    1996-02-01

    Introduction of pentagon-heptagon pair defects into the hexagonal network of a single carbon nanotube can change the helicity of the tube and alter its electronic structure. Using a tight-binding method to calculate the electronic structure of such systems we show that they behave as nanoscale metal/semiconductor or semiconductor/semiconductor junctions. These junctions could be the building blocks of nanoscale electronic devices made entirely of carbon. {copyright} {ital 1996 The American Physical Society.}

  1. Development of Nanoscale Graphitic Devices and The Transport Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Gunasekaran, Venugopal

    2011-02-15

    This dissertation describes the development of graphitic based nanoscale devices with its fabrication and transport characterization results. It covers graphite nano-scale stacked-junctions fabricated using focused ion beam (FIB) 3-D etching technique, a single layer graphite layer (graphene) preparation and its electrical transport characterization results and the synthesis and investigation of electrical transport behavior of graphene oxide based thin film devices. The first chapter describes the basic information about the carbon family in detail in which the electronic properties and structure of graphite, graphene and graphene oxide are discussed. In addition, the necessity of developing nanoscale graphitic devices is given. The second chapter explains the experimental techniques used in this research for fabricating nanoscale devices which includes focused ion beam 3-D fabrication procedures, mechanical exfoliation technique and photolithographic methods. In third chapter, we have reported the results on temperature dependence of graphite planar-type structures fabricated along ab-plane. In the fourth and fifth chapters, the fabrication and electrical transport characteristics of large in-plane area graphite planar-type structures (fabricated along ab-plane and c-axis) were discussed and their transport anisotropy properties were investigated briefly. In the sixth chapter, we focused the fabrication of the submicron sized graphite stacked junctions and their electrical transport characterization studies. In which, FIB was used to fabricated the submicron junctions with various in-plane area (with same stack height) are and their transport characteristics were compared. The seventh chapter reports investigation of electrical transport results of nanoscale graphite stacked-junctions in which the temperature dependent transport (R-T) studies, current-voltage measurements for the various in-plane areas and for various stack height samples were analyzed. The

  2. Design and synthesis of "dumb-bell" and "triangular" inorganic-organic hybrid nanopolyoxometalate clusters and their characterisation through ESI-MS analyses.

    Science.gov (United States)

    Pradeep, Chullikkattil P; Li, Feng-Yan; Lydon, Claire; Miras, Haralampos N; Long, De-Liang; Xu, Lin; Cronin, Leroy

    2011-06-27

    A series of tris(hydroxymethyl)aminomethane (TRIS)-based linear (bis(TRIS)) and triangular (tris(TRIS)) ligands has been synthesised and were covalently attached to the Wells-Dawson type cluster [P(2)V(3)W(15)O(62)](9-) to generate a series of nanometer-sized inorganic-organic hybrid polyoxometalate clusters. These huge hybrids, with a molecular mass similar to that of small proteins in the range of ≈10-16 kDa, were unambiguously characterised by using high-resolution ESI-MS. The ESI-MS spectra of these compounds revealed, in negative ion mode, a characteristic pattern showing distinct groups of peaks corresponding to different anionic charge states ranging from 3(-) to 8(-) for the hybrids. Each peak in these individual groups could be unambiguously assigned to the corresponding hybrid cluster anion with varying combinations of tetrabutylammonium (TBA) and other cations. This study therefore highlights the prowess of the high-resolution ESI-MS for the unambiguous characterisation of large, nanoscale, inorganic-organic hybrid clusters that have huge mass, of the order of 10-16 kDa. Also, the designed synthesis of these compounds points to the fact that we were able to achieve a great deal of structural pre-design in the synthesis of these inorganic-organic hybrid polyoxometalates (POMs) by means of a ligand design route, which is often not possible in traditional "one-pot" POM synthesis.

  3. Nanoscale Mixing of Soft Solids

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Soo-Hyung; Lee, Sangwoo; Soto, Haidy E.; Lodge, Timothy P.; Bates, Frank S. (UMM); (Texas)

    2013-03-07

    Assessing the state of mixing on the molecular scale in soft solids is challenging. Concentrated solutions of micelles formed by self-assembly of polystyrene-block-poly(ethylene-alt-propylene) (PS-PEP) diblock copolymers in squalane (C{sub 30}H{sub 62}) adopt a body-centered cubic (bcc) lattice, with glassy PS cores. Utilizing small-angle neutron scattering (SANS) and isotopic labeling ({sup 1}H and {sup 2}H (D) polystyrene blocks) in a contrast-matching solvent (a mixture of squalane and perdeuterated squalane), we demonstrate quantitatively the remarkable fact that a commercial mixer can create completely random mixtures of micelles with either normal, PS(H), or deuterium-labeled, PS(D), cores on a well-defined bcc lattice. The resulting SANS intensity is quantitatively modeled by the form factor of a single spherical core. These results demonstrate both the possibility of achieving complete nanoscale mixing in a soft solid and the use of SANS to quantify the randomness.

  4. Molecular Photovoltaics in Nanoscale Dimension

    Directory of Open Access Journals (Sweden)

    Andrei V. Pakoulev

    2011-01-01

    Full Text Available This review focuses on the intrinsic charge transport in organic photovoltaic (PVC devices and field-effect transistors (SAM-OFETs fabricated by vapor phase molecular self-assembly (VP-SAM method. The dynamics of charge transport are determined and used to clarify a transport mechanism. The 1,4,5,8-naphthalene-tetracarboxylic diphenylimide (NTCDI SAM devices provide a useful tool to study the fundamentals of polaronic transport at organic surfaces and to discuss the performance of organic photovoltaic devices in nanoscale. Time-resolved photovoltaic studies allow us to separate the charge annihilation kinetics in the conductive NTCDI channel from the overall charge kinetic in a SAM-OFET device. It has been demonstrated that tuning of the type of conductivity in NTCDI SAM-OFET devices is possible by changing Si substrate doping. Our study of the polaron charge transfer in organic materials proposes that a cation-radical exchange (redox mechanism is the major transport mechanism in the studied SAM-PVC devices. The role and contribution of the transport through delocalized states of redox active surface molecular aggregates of NTCDI are exposed and investigated. This example of technological development is used to highlight the significance of future technological development of nanotechnologies and to appreciate a structure-property paradigm in organic nanostructures.

  5. Dielectrophoretic Forces on the Nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Schaldach, C M; Bourcier, W L; Wilson, W D; Paul, P H

    2004-03-30

    We have developed a method of calculation of the dielectrophoretic force on a nanoparticle in a fluid environment where variations in the electric field and electric field gradients are on the same nanoscale as the particle. The Boundary Element Dielectrophoretic Force (BEDF) method involves constructing a solvent-accessible or molecular surface surrounding the particle, calculating the normal component of the electric field at the surface boundary elements and then solving a system of linear equations for the induced surface polarization charge on each element. Different surface elements of the molecule may experience quite different polarizing electric fields, unlike the situation in the point dipole approximation. A single 100 Angstrom radius ring test configuration is employed to facilitate comparison with the well-known point dipole approximation (PDA). We find remarkable agreement between the forces calculated by the BEDF and PDA methods for a 1 Angstrom polarizable sphere. However, for larger particles, the differences between the methods become qualitative as well as quantitative; the character of the force changes from attractive at the origin of the ring for a 50 Angstrom sphere, to repulsive for a 75 Angstrom sphere. Equally dramatic differences are found in a more complex electrical environment involving two sets of 10 rings.

  6. Asymmetric Hybrid Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chumanov, George [Clemson Univ., SC (United States)

    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.

  7. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ 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 pbar annihilation.

  8. High performance carbon nanotube - polymer nanofiber hybrid fabrics

    Science.gov (United States)

    Yildiz, Ozkan; Stano, Kelly; Faraji, Shaghayegh; Stone, Corinne; Willis, Colin; Zhang, Xiangwu; Jur, Jesse S.; Bradford, Philip D.

    2015-10-01

    Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m-2 exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical

  9. Nanoscale ferroelectrics and multiferroics key processes and characterization issues, and nanoscale effects

    CERN Document Server

    Alguero, Miguel

    2016-01-01

    This book reviews the key issues in processing and characterization of nanoscale ferroelectrics and multiferroics, and provides a comprehensive description of their properties, with an emphasis in differentiating size effects of extrinsic ones like boundary or interface effects. Recently described nanoscale novel phenomena are also addressed. Organized into three parts it addresses key issues in processing (nanostructuring), characterization (of the nanostructured materials) and nanoscale effects. Taking full advantage of the synergies between nanoscale ferroelectrics and multiferroics, it covers materials nanostructured at all levels, from ceramic technologies like ferroelectric nanopowders, bulk nanostructured ceramics and thick films, and magnetoelectric nanocomposites, to thin films, either polycrystalline layer heterostructures or epitaxial systems, and to nanoscale free standing objects with specific geometries, such as nanowires and tubes at different levels of development. The book is developed from t...

  10. Methods and devices for fabricating three-dimensional nanoscale structures

    Science.gov (United States)

    Rogers, John A.; Jeon, Seokwoo; Park, Jangung

    2010-04-27

    The present invention provides methods and devices for fabricating 3D structures and patterns of 3D structures on substrate surfaces, including symmetrical and asymmetrical patterns of 3D structures. Methods of the present invention provide a means of fabricating 3D structures having accurately selected physical dimensions, including lateral and vertical dimensions ranging from 10s of nanometers to 1000s of nanometers. In one aspect, methods are provided using a mask element comprising a conformable, elastomeric phase mask capable of establishing conformal contact with a radiation sensitive material undergoing photoprocessing. In another aspect, the temporal and/or spatial coherence of electromagnetic radiation using for photoprocessing is selected to fabricate complex structures having nanoscale features that do not extend entirely through the thickness of the structure fabricated.

  11. Nanoscale nonlinear PANDA ring resonator

    CERN Document Server

    Yupapin, Preecha

    2012-01-01

    Microring/nanoring resonator is an interesting device that has been widely studied and investigated by researchers from a variety of specializations. This book begins with the basic background of linear and nonlinear ring resonators. A novel design of nano device known as a PANDA ring resonator is proposed. The use of the device in the form of a PANDA in applications such as nanoelectronics, measurement, communication, sensors, optical and quantum computing, drug delivery, hybrid transistor and a new concept of electron-hole pair is discussed in detail.

  12. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  13. Attosecond Physics at the nanoscale.

    Science.gov (United States)

    Ciappina, Marcelo F; Perez-Hernandez, J; Landsman, Alexandra; Okell, William; Zherebtsov, Sergey; Förg, Benjamin; Schötz, Johannes; Seiffert, Lennart; Fennel, Thomas; Shaaran, Tahir; Zimmermann, Tomas; Chacón, Alexis; Guichard, Roland; Zair, Amelle; Tisch, John; Marangos, J; Witting, Tobias; Braun, Avi; Maier, Stefan; Roso, Luis; Krüger, Michael; Hommelhoff, Peter; Kling, Matthias; Krausz, Ferenc; Lewenstein, Maciej

    2017-01-06

    Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds, which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is 152 as. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this report on progress we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metal- lic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as above-threshold ionization and high-order harmonic generation. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nano physics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the induced fields and the unique electron dynamics initiated

  14. Nanoscale transformation of sp{sup 2} to sp{sup 3} of graphite by slow highly charged ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Meguro, T. E-mail: meguro@postman.riken.go.jp; Hida, A.; Koguchi, Y.; Miyamoto, S.; Yamamoto, Y.; Takai, H.; Maeda, K.; Aoyagi, Y

    2003-08-01

    Nanoscale transformation of electronic states by highly charged ion (HCI) impact on graphite surfaces is described. The high potential energy of slow HCI, which induces multiple emission of electrons from the surface, provides a strong modification of the electronic states of the local area upon graphite surfaces. The HCI impact and the subsequent surface treatment either by electron injection from a scanning tunneling microscopy tip or by He-Cd laser irradiation induce a localized transition from sp{sup 2} to sp{sup 3} hybridization in graphite, resulting in the formation of nanoscale diamond-like structures (nanodiamond) at the impact region. From Raman spectroscopic measurements on sp{sup 2} related peaks, it is found that the HCI irradiation creates vacancy complexes in contrast to ions having a lower charge state, which generate single vacancies. It is of interest that a single impact of HCI creates one nanodiamond structure, suggesting potential applications of HCI in nanoscale material processing.

  15. Nanoscale integration is the next frontier for nanotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Samuel T [Los Alamos National Laboratory

    2009-01-01

    Nanoscale integration of materials and structures is the next critical step to exploit the promise of nanomaterials. Many novel and fascinating properties have been revealed for nanostructured materials. But if nanotechnology is to live up to its promise we must incorporate these nanoscale building blocks into functional systems that connect to the micro- and macroscale world. To do this we will inevitably need to understand and exploit the resulting combined unique properties of these integrated nanosystems. Much science waits to be discovered in the process. Nanoscale integration extends from the synthesis and fabrication of individual nanoscale building blocks, to the assembly of these building blocks into composite structures, and finally to the formation of complex functional systems. As illustrated in Figure 1, the building blocks may be homogeneous or heterogeneous, the composite materials may be nanocomposite or patterned structures, and the functional systems will involve additional combinations of materials. Nanoscale integration involves assembling diverse nanoscale materials across length scales to design and achieve new properties and functionality. At each stage size-dependent properties, the influence of surfaces in close proximity, and a multitude of interfaces all come into play. Whether the final system involves coherent electrons in a quantum computing approach, the combined flow of phonons and electrons for a high efficiency thermoelectric micro-generator, or a molecular recognition structure for bio-sensing, the combined effects of size, surface, and interface will be critical. In essence, one wants to combine the novel functions available through nanoscale science to achieve unique multi-functionalities not available in bulk materials. Perhaps the best-known example of integration is that of combining electronic components together into very large scale integrated circuits (VLSI). The integrated circuit has revolutionized electronics in many

  16. Accurate measurement of liquid transport through nanoscale conduits

    Science.gov (United States)

    Alibakhshi, Mohammad Amin; Xie, Quan; Li, Yinxiao; Duan, Chuanhua

    2016-01-01

    Nanoscale liquid transport governs the behaviour of a wide range of nanofluidic systems, yet remains poorly characterized and understood due to the enormous hydraulic resistance associated with the nanoconfinement and the resulting minuscule flow rates in such systems. To overcome this problem, here we present a new measurement technique based on capillary flow and a novel hybrid nanochannel design and use it to measure water transport through single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our results show that silica nanochannels exhibit increased mass flow resistance compared to the classical hydrodynamics prediction. This difference increases with decreasing channel height and reaches 45% in the case of 7 nm nanochannels. This resistance increase is attributed to the formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. By avoiding use of any pressure and flow sensors or any theoretical estimations the hybrid nanochannel scheme enables facile and precise flow measurement through single nanochannels, nanotubes, or nanoporous media and opens the prospect for accurate characterization of both hydrophilic and hydrophobic nanofluidic systems. PMID:27112404

  17. Integration of nanoscale memristor synapses in neuromorphic computing architectures

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Legenstein, Robert; Deligeorgis, George; Prodromakis, Themistoklis

    2013-09-01

    Conventional neuro-computing architectures and artificial neural networks have often been developed with no or loose connections to neuroscience. As a consequence, they have largely ignored key features of biological neural processing systems, such as their extremely low-power consumption features or their ability to carry out robust and efficient computation using massively parallel arrays of limited precision, highly variable, and unreliable components. Recent developments in nano-technologies are making available extremely compact and low power, but also variable and unreliable solid-state devices that can potentially extend the offerings of availing CMOS technologies. In particular, memristors are regarded as a promising solution for modeling key features of biological synapses due to their nanoscale dimensions, their capacity to store multiple bits of information per element and the low energy required to write distinct states. In this paper, we first review the neuro- and neuromorphic computing approaches that can best exploit the properties of memristor and scale devices, and then propose a novel hybrid memristor-CMOS neuromorphic circuit which represents a radical departure from conventional neuro-computing approaches, as it uses memristors to directly emulate the biophysics and temporal dynamics of real synapses. We point out the differences between the use of memristors in conventional neuro-computing architectures and the hybrid memristor-CMOS circuit proposed, and argue how this circuit represents an ideal building block for implementing brain-inspired probabilistic computing paradigms that are robust to variability and fault tolerant by design.

  18. Fabrication of nanoscale speckle using broad ion beam milling on polymers for deformation analysis

    Directory of Open Access Journals (Sweden)

    Qinghua Wang

    2016-07-01

    Full Text Available We first report a fabrication technique of nanoscale speckle patterns on polymers using broad ion beam milling. The proposed technique is simple and low-cost to produce speckles ranging from dozens of nanometers to less than three micrometers in a large area of several millimeters. Random patterns were successfully produced with an argon (Ar ion beam on the surfaces of four kinds of polymers: the epoxy matrix of carbon fiber reinforced plastic, polyester, polyvinyl formal-acetal, and polyimide. The speckle morphologies slightly vary with different polymers. The fabricated speckle patterns have good time stability and are promising to be used to measure the nanoscale deformations of polymers using the digital image correlation method.

  19. Alignment of Nanoscale Single-Walled Carb on Nanotub es Strands

    Institute of Scientific and Technical Information of China (English)

    Danna Yang; Lin Wang; Xiaoxian Zhang; Dongwei Wang; Zhiqiang Shen; Sai Li

    2011-01-01

    Depositing single-walled carbon nanotubes (SWNTs) with controllable density, pattern and ori-entation on electrodes presents a challenge in today’s research. Here, we report a novel solvent evaporation method to align SWNTs in patterns having nanoscale width and micronscale length. SWNTs suspension has been introduced dropwise onto photoresist resin microchannels; and the capillary force can stretch and align SWNTs into strands with nanoscale width in the microchannels. Then these narrow and long aligned SWNTs patterns were successfully transferred to a pair of gold electrodes with different gaps to fabricate carbon nan-otube field-effect transistor (CNTFET). Moreover, the electrical performance of the CNTFET show that the SWNTs strands can bridge different gaps and fabricate good electrical performance CNTFET with ON/OFF ratio around 106. This result suggests a promising and simple strategy for assembling well-aligned SWNTs into CNTFET device with good electrical performance.

  20. Hybrid optical-thermal antennas for enhanced light focusing and local temperature control

    CERN Document Server

    Boriskina, Svetlana V; Tong, Jonathan K; Hsu, Wei-Chun; Chen, Gang

    2016-01-01

    Metal nanoantennas supporting localized surface plasmon resonances have become an indispensable tool in bio(chemical) sensing and nanoscale imaging applications. The high plasmon-enhanced electric field intensity in the visible or near-IR range that enables the above applications may also cause local heating of nanoantennas. We present a design of hybrid optical-thermal antennas that simultaneously enable intensity enhancement at the operating wavelength in the visible and nanoscale local temperature control. We demonstrate a possibility to reduce the hybrid antenna operating temperature via enhanced infrared thermal emission. We predict via rigorous numerical modeling that hybrid optical-thermal antennas that support high-quality-factor photonic-plasmonic modes enable up to two orders of magnitude enhancement of localized electric fields and of the optical power absorbed in the nanoscale metal volume. At the same time, the hybrid antenna temperature can be lowered by several hundred degrees with respect to i...

  1. Preparation and Characterization of Organic/Inorganic Hybrid Nanofibers

    Institute of Scientific and Technical Information of China (English)

    WU Ning; WEI Qu-fu; LI Qi; XU Wen-zheng

    2006-01-01

    A new class of nanocomposites based on organic and inorganic species integrated at a nanoscale has obtained more attention these years. Organic-inorganic hybrids have both the advantages of organic materials, such as light weight, flexibility and good moldability, and inorganic materials, such as high strength, heat stability and chemical resistance. In this work, PVAc/TiO2 organicinorganic hybrid was prepared by sol-gel process. Electrospinning technique was used to fabricate PVAc/TiO2hybrid nanofibers. The structures and properties of the hybrid nanofibers were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM),Differential Scanning Calorimeter (DSC) and Fouriertransform infrared (FTIR) spectra. SEM and AFM were employed to study the topography of the hybrid nanofibers.The chemical structure of the hybrid nanofibers were examined by FTIR. The DSC scansrevealed the second order transition temperature of the hybrid materials were higher than PVAc.

  2. Far-field nanoscale infrared spectroscopy of vibrational fingerprints of molecules with graphene plasmons

    CERN Document Server

    Hu, Hai; Zhai, Feng; Hu, Debo; Liu, Ruina; Liu, Kaihui; Sun, Zhipei; Dai, Qing

    2016-01-01

    Infrared spectroscopy, especially for molecular vibrations in the fingerprint region between 600 and 1500 cm-1, is a powerful characterization method for bulk materials. However, molecular fingerprinting at the nanoscale level still remains a significant challenge, due to weak light-matter interaction between micron-wavelengthed infrared light and nano-sized molecules. Here, we demonstrate molecular fingerprinting at the nanoscale level using our specially designed graphene plasmonic structure on CaF2 nanofilm. This structure not only avoids the plasmon-phonon hybridization, but also provides in situ electrically-tunable graphene plasmon covering the entire infrared fingerprint region, which was previously unattainable. In addition, undisturbed and highly-confined graphene plasmon offers simultaneous detection of in-plane and out-of-plane vibrational modes with ultrahigh detection sensitivity down to the sub-monolayer level, significantly pushing the current detection limit of far-field mid-infrared spectrosc...

  3. Nanoscale resolution immersion scanning thermal microscopy

    CERN Document Server

    Tovee, Peter D

    2013-01-01

    Nanoscale thermal properties are becoming of extreme importance for modern electronic circuits that dissipate increasing power on the length scale of few tens of nanometers, and for chemical and physical properties sensors and biosensors using nanoscale sized features. While Scanning Thermal Microscopy (SThM) is known for its ability to probe thermal properties and heat generation with nanoscale resolution, until today it was perceived impossible to use it in the liquid environment due to dominating direct heat exchange between microfabricated thermal probe and surrounding liquid that would deteriorate spatial resolution. Nonetheless, our theoretical analysis of SThM in liquids showed that for certain design of SThM probe with resistive heater located near the probe tip, their thermal signal is only moderately affected, by less than half on immersion in a dodecane environment. More significantly, its spatial resolution, surprisingly, would remain practically unaffected, and the thermal contact between the tip...

  4. Nanoscale thermometry using point contact thermocouples.

    Science.gov (United States)

    Sadat, Seid; Tan, Aaron; Chua, Yi Jie; Reddy, Pramod

    2010-07-14

    Probing temperature fields with nanometer resolution is critical to understanding nanoscale thermal transport as well as dissipation in nanoscale devices. Here, we demonstrate an atomic force microscope (AFM)-based technique capable of mapping temperature fields in metallic films with approximately 10 mK temperature resolution and thermocouples on a grid. The local temperature at each point contact is obtained by measuring the thermoelectric voltage of the platinum-gold point contact and relating it to the local temperature. These results demonstrate a direct measurement of the temperature field of a metallic surface without using specially fabricated scanning temperature-probes.

  5. Nanoscale Lasers Based on Carbon Peapods

    Institute of Scientific and Technical Information of China (English)

    HE Shao-Long; SHEN Jian-Qi

    2006-01-01

    A scheme of nanoscale lasers based on the so-called carbon peapods is examined in detail.Since there is considerable cylindrical empty space in the middle of a single-wall carbon nanotube (SWCNT),it can serve as a laser resonant cavity that consists of two highly reflecting alignment "mirrors" separated by a distance.These mirrors refer to ordered arrays of C60 inside SWCNTs,which have photonic bandgap structures.Meanwhile,ideally single-mode lasers are supposed to be produced in the nanoscale resonant cavity.

  6. Atomic nanoscale technology in the nuclear industry

    CERN Document Server

    Woo, Taeho

    2011-01-01

    Developments at the nanoscale are leading to new possibilities and challenges for nuclear applications in areas ranging from medicine to international commerce to atomic power production/waste treatment. Progress in nanotech is helping the nuclear industry slash the cost of energy production. It also continues to improve application reliability and safety measures, which remain a critical concern, especially since the reactor disasters in Japan. Exploring the new wide-ranging landscape of nuclear function, Atomic Nanoscale Technology in the Nuclear Industry details the breakthroughs in nanosca

  7. Nanoscale chirality in metal and semiconductor nanoparticles.

    Science.gov (United States)

    Kumar, Jatish; Thomas, K George; Liz-Marzán, Luis M

    2016-10-18

    The field of chirality has recently seen a rejuvenation due to the observation of chirality in inorganic nanomaterials. The advancements in understanding the origin of nanoscale chirality and the potential applications of chiroptical nanomaterials in the areas of optics, catalysis and biosensing, among others, have opened up new avenues toward new concepts and design of novel materials. In this article, we review the concept of nanoscale chirality in metal nanoclusters and semiconductor quantum dots, then focus on recent experimental and theoretical advances in chiral metal nanoparticles and plasmonic chirality. Selected examples of potential applications and an outlook on the research on chiral nanomaterials are additionally provided.

  8. Chromosome congression explained by nanoscale electrostatics.

    Science.gov (United States)

    Gagliardi, L John; Shain, Daniel H

    2014-02-24

    Nanoscale electrostatic microtubule disassembly forces between positively charged molecules in kinetochores and negative charges on plus ends of microtubules have been implicated in poleward chromosome motions and may also contribute to antipoleward chromosome movements. We propose that chromosome congression can be understood in terms of antipoleward nanoscale electrostatic microtubule assembly forces between negatively charged microtubule plus ends and like-charged chromosome arms, acting in conjunction with poleward microtubule disassembly forces. Several other aspects of post-attachment prometaphase chromosome motions, as well as metaphase oscillations, are consistently explained within this framework.

  9. Palm oil and cardiovascular disease: a randomized trial of the effects of hybrid palm oil supplementation on human plasma lipid patterns.

    Science.gov (United States)

    Lucci, P; Borrero, M; Ruiz, A; Pacetti, D; Frega, N G; Diez, O; Ojeda, M; Gagliardi, R; Parra, L; Angel, M

    2016-01-01

    This study examines, for the first time, the effect of hybrid Elaeis oleifera × E. guineensis palm oil supplementation on human plasma lipids related to CVD risk factors. One hundred sixty eligible participants were randomized and assigned to one of the two treatments: 25 mL hybrid palm oil (HPO group) or 25 mL extra virgin olive oil (EVOO group) daily for 3 months. Fasting venous samples were obtained at baseline and after 1, 2 and 3 months for measurement of plasma lipids (TC, LDL-C, HDL-C and TAGs). Changes in body mass index and waist circumference were also assessed. Although there was an overall reduction in TC (7.4%, p palm oil can be seen as a "tropical equivalent of olive oil".

  10. Functionalising surfaces at the nanoscale using plasma technology.

    Science.gov (United States)

    Moore, R

    2009-01-01

    Plasma technology offers a highly effective toolbox for nanoscale surface engineering of materials. The potential variety of nanoscale features and new properties that can be achieved are reviewed here.

  11. Plant virus directed fabrication of nanoscale materials and devices.

    Science.gov (United States)

    Culver, James N; Brown, Adam D; Zang, Faheng; Gnerlich, Markus; Gerasopoulos, Konstantinos; Ghodssi, Reza

    2015-05-01

    Bottom-up self-assembly methods in which individual molecular components self-organize to form functional nanoscale patterns are of long-standing interest in the field of materials sciences. Such self-assembly processes are the hallmark of biology where complex macromolecules with defined functions assemble from smaller molecular components. In particular, plant virus-derived nanoparticles (PVNs) have drawn considerable attention for their unique self-assembly architectures and functionalities that can be harnessed to produce new materials for industrial and biomedical applications. In particular, PVNs provide simple systems to model and assemble nanoscale particles of uniform size and shape that can be modified through molecularly defined chemical and genetic alterations. Furthermore, PVNs bring the added potential to "farm" such bio-nanomaterials on an industrial scale, providing a renewable and environmentally sustainable means for the production of nano-materials. This review outlines the fabrication and application of several PVNs for a range of uses that include energy storage, catalysis, and threat detection.

  12. Nanoscale superstructures assembled by polymerase chain reaction (PCR): programmable construction, structural diversity, and emerging applications.

    Science.gov (United States)

    Kuang, Hua; Ma, Wei; Xu, Liguang; Wang, Libing; Xu, Chuanlai

    2013-11-19

    Polymerase chain reaction (PCR) is an essential tool in biotechnology laboratories and is becoming increasingly important in other areas of research. Extensive data obtained over the last 12 years has shown that the combination of PCR with nanoscale dispersions can resolve issues in the preparation DNA-based materials that include both inorganic and organic nanoscale components. Unlike conventional DNA hybridization and antibody-antigen complexes, PCR provides a new, effective assembly platform that both increases the yield of DNA-based nanomaterials and allows researchers to program and control assembly with predesigned parameters including those assisted and automated by computers. As a result, this method allows researchers to optimize to the combinatorial selection of the DNA strands for their nanoparticle conjugates. We have developed a PCR approach for producing various nanoscale assemblies including organic motifs such as small molecules, macromolecules, and inorganic building blocks, such as nanorods (NRs), metal, semiconductor, and magnetic nanoparticles (NPs). We start with a nanoscale primer and then modify that building block using the automated steps of PCR-based assembly including initialization, denaturation, annealing, extension, final elongation, and final hold. The intermediate steps of denaturation, annealing, and extension are cyclic, and we use computer control so that the assembled superstructures reach their predetermined complexity. The structures assembled using a small number of PCR cycles show a lower polydispersity than similar discrete structures obtained by direct hybridization between the nanoscale building blocks. Using different building blocks, we assembled the following structural motifs by PCR: (1) discrete nanostructures (NP dimers, NP multimers including trimers, pyramids, tetramers or hexamers, etc.), (2) branched NP superstructures and heterochains, (3) NP satellite-like superstructures, (4) Y-shaped nanostructures and DNA

  13. Nanoscale chemical sensor based on organic thin-film transistors

    Science.gov (United States)

    Wang, Liang; Fine, Daniel; Dodabalapur, Ananth

    2004-12-01

    Nanoscale organic thin-film transistors were fabricated to investigate their chemical sensing properties. The use of a four-terminal geometry ensures that the sensor active area is truly nanoscale, and eliminates undesirable spreading currents. The sensor response was markedly different in nanoscale sensors compared to large-area sensors for the same analyte-semiconductor combination. The chemical sensing mechanisms in both microscale and nanoscale transistors are briefly discussed.

  14. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  15. Prepare dispersed CIS nano-scale particles and spray coating CIS absorber layers using nano-scale precursors.

    Science.gov (United States)

    Liou, Jian-Chiun; Diao, Chien-Chen; Lin, Jing-Jenn; Chen, Yen-Lin; Yang, Cheng-Fu

    2014-01-01

    In this study, the Mo-electrode thin films were deposited by a two-stepped process, and the high-purity copper indium selenide-based powder (CuInSe2, CIS) was fabricated by hydrothermal process by Nanowin Technology Co. Ltd. From the X-ray pattern of the CIS precursor, the mainly crystalline phase was CIS, and the almost undetectable CuSe phase was observed. Because the CIS powder was aggregated into micro-scale particles and the average particle sizes were approximately 3 to 8 μm, the CIS power was ground into nano-scale particles, then the 6 wt.% CIS particles were dispersed into isopropyl alcohol to get the solution for spray coating method. Then, 0.1 ml CIS solution was sprayed on the 20 mm × 10 mm Mo/glass substrates, and the heat treatment for the nano-scale CIS solution under various parameters was carried out in a selenization furnace. The annealing temperature was set at 550°C, and the annealing time was changed from 5 to 30 min, without extra Se content was added in the furnace. The influences of annealing time on the densification, crystallization, resistivity (ρ), hall mobility (μ), and carrier concentration of the CIS absorber layers were well investigated in this study.

  16. Ants exhibit asymmetric hybridization in a mosaic hybrid zone.

    Science.gov (United States)

    Purcell, Jessica; Zahnd, Sacha; Athanasiades, Anouk; Türler, Rebecca; Chapuisat, Michel; Brelsford, Alan

    2016-10-01

    Research on hybridization between species provides unparalleled insights into the pre- and postzygotic isolating mechanisms that drive speciation. In social organisms, colony-level incompatibilities may provide additional reproductive barriers not present in solitary species, and hybrid zones offer an opportunity to identify these barriers. Here, we use genotyping-by-sequencing to sequence hundreds of markers in a hybrid zone between two socially polymorphic ant species, Formica selysi and Formica cinerea. We characterize the zone, determine the frequency of hybrid workers, infer whether hybrid queens or males are produced and investigate whether hybridization is influenced by colony social organization. We also compare cuticular hydrocarbon profiles and aggression levels between the two species. The hybrid zone exhibits a mosaic structure. The asymmetric distribution of hybrids skewed towards F. cinerea suggests a pattern of unidirectional nuclear gene flow from F. selysi into F. cinerea. The occurrence of backcrossed individuals indicates that hybrid queens and/or males are fertile, and the presence of the F. cinerea mitochondrial haplotype in 97% of hybrids shows that successful F1 hybrids will generally have F. cinerea mothers and F. selysi fathers. We found no evidence that social organization contributes to speciation, because hybrids occur in both single-queen and multiple-queen colonies. Strongly differentiated cuticular hydrocarbon profiles and heightened interspecific aggression further reveal that species recognition cues are both present and perceived. The discovery of fertile hybrids and asymmetrical gene flow is unusual in ants, and this hybrid zone will therefore provide an ideal system with which to investigate speciation in social insects.

  17. Nanoscale temperature sensing using the Seebeck effect

    NARCIS (Netherlands)

    Bakker, F. L.; Flipse, J.; van Wees, B. J.

    2012-01-01

    We experimentally study the effect of Joule heating on the electron temperature in metallic nanoscale devices and compare the results with a diffusive 3D finite element model. The temperature is probed using four thermocouples located at different distances from the heater. A good quantitative agree

  18. Status and perspectives of nanoscale device modelling

    DEFF Research Database (Denmark)

    Macucci, M.; Lannaccone, G.; Greer, J.;

    2001-01-01

    and the future perspectives of nanoscale device modelling. The outcome of such a discussion is summarized in the present paper, outlining the major challenges for the future, such as the integration of nonequilibrium phenomena and of molecular scale properties. We believe that modelling has a growing importance...

  19. Anomalous freezing behavior of nanoscale liposomes

    DEFF Research Database (Denmark)

    Spangler, E. J.; Kumar, P. B. S.; Laradji, M.

    2012-01-01

    The effect of the finite size of one-component liposomes on their phase behavior is investigated via simulations of an implicit-solvent model of self-assembled lipid bilayers. We found that the high curvature of nanoscale liposomes has a significant effect on their freezing behavior. While...

  20. Selective nanoscale growth of lattice mismatched materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Chang; Brueck, Steven R. J.

    2017-06-20

    Exemplary embodiments provide materials and methods of forming high-quality semiconductor devices using lattice-mismatched materials. In one embodiment, a composite film including one or more substantially-single-particle-thick nanoparticle layers can be deposited over a substrate as a nanoscale selective growth mask for epitaxially growing lattice-mismatched materials over the substrate.

  1. Nanoscale temperature sensing using the Seebeck effect

    NARCIS (Netherlands)

    Bakker, F. L.; Flipse, J.; van Wees, B. J.

    2012-01-01

    We experimentally study the effect of Joule heating on the electron temperature in metallic nanoscale devices and compare the results with a diffusive 3D finite element model. The temperature is probed using four thermocouples located at different distances from the heater. A good quantitative

  2. Bio-Conjugates for Nanoscale Applications

    DEFF Research Database (Denmark)

    Villadsen, Klaus

    Bio-conjugates for Nanoscale Applications is the title of this thesis, which covers three different projects in chemical bio-conjugation research, namely synthesis and applications of: Lipidated fluorescent peptides, carbohydrate oxime-azide linkers and N-aryl O-R2 oxyamine derivatives. Lipidated...

  3. Adsorption Kinetics in Nanoscale Porous Coordination Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Nune, Satish K.; Thallapally, Praveen K.; McGrail, Benard Peter; Annapureddy, Harsha V. R.; Dang, Liem X.; Mei, Donghai; Karri, Naveen; Alvine, Kyle J.; Olszta, Matthew J.; Arey, Bruce W.; Dohnalkova, Alice

    2015-10-07

    Nanoscale porous coordination polymers were synthesized using simple wet chemical method. The effect of various polymer surfactants on colloidal stability and shape selectivity was investigated. Our results suggest that the nanoparticles exhibited significantly improved adsorption kinetics compared to bulk crystals due to decreased diffusion path lengths and preferred crystal plane interaction.

  4. Direct temperature mapping of nanoscale plasmonic devices.

    Science.gov (United States)

    Desiatov, Boris; Goykhman, Ilya; Levy, Uriel

    2014-02-12

    Side by side with the great advantages of plasmonics in nanoscale light confinement, the inevitable ohmic loss results in significant joule heating in plasmonic devices. Therefore, understanding optical-induced heat generation and heat transport in integrated on-chip plasmonic devices is of major importance. Specifically, there is a need for in situ visualization of electromagnetic induced thermal energy distribution with high spatial resolution. This paper studies the heat distribution in silicon plasmonic nanotips. Light is coupled to the plasmonic nanotips from a silicon nanowaveguide that is integrated with the tip on chip. Heat is generated by light absorption in the metal surrounding the silicon nanotip. The steady-state thermal distribution is studied numerically and measured experimentally using the approach of scanning thermal microscopy. It is shown that following the nanoscale heat generation by a 10 mW light source within a silicon photonic waveguide the temperature in the region of the nanotip is increased by ∼ 15 °C compared with the ambient temperature. Furthermore, we also perform a numerical study of the dynamics of the heat transport. Given the nanoscale dimensions of the structure, significant heating is expected to occur within the time frame of picoseconds. The capability of measuring temperature distribution of plasmonic structures at the nanoscale is shown to be a powerful tool and may be used in future applications related to thermal plasmonic applications such as control heating of liquids, thermal photovoltaic, nanochemistry, medicine, heat-assisted magnetic memories, and nanolithography.

  5. Fats, Oils, & Colors of a Nanoscale Material

    Science.gov (United States)

    Lisensky, George C.; Horoszewski, Dana; Gentry, Kenneth L.; Zenner, Greta M.; Crone, Wendy C .

    2006-01-01

    Phase changes and intermolecular forces are important physical science concepts but are not always easy to present in an active learning format. This article presents several interactive activities in which students plot the melting points of some fatty acids and explore the effect that the nanoscale size and shape of molecules have on the…

  6. Traceable nanoscale measurement at NML-SIRIM

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Ahmad M.; Abdul Hapip, A. I. [National Metrology Laboratory SIRIM Berhad (NML-SIRIM), Lot PT 4803, Bandar Baru Salak Tinggi, 43900 Sepang (Malaysia)

    2012-06-29

    The role of national metrology institute (NMI) has always been very crucial in national technology development. One of the key activities of the NMI is to provide traceable measurement in all parameters under the International System of Units (SI). Dimensional measurement where size and shape are two important features investigated, is one of the important area covered by NMIs. To support the national technology development, particularly in manufacturing sectors and emerging technology such nanotechnology, the National Metrology Laboratory, SIRIM Berhad (NML-SIRIM), has embarked on a project to equip Malaysia with state-of-the-art nanoscale measurement facility with the aims of providing traceability of measurement at nanoscale. This paper will look into some of the results from current activities at NML-SIRIM related to measurement at nanoscale particularly on application of atomic force microscope (AFM) and laser based sensor in dimensional measurement. Step height standards of different sizes were measured using AFM and laser-based sensors. These probes are integrated into a long-range nanoscale measuring machine traceable to the international definition of the meter thus ensuring their traceability. Consistency of results obtained by these two methods will be discussed and presented. Factors affecting their measurements as well as their related uncertainty of measurements will also be presented.

  7. Bio-Conjugates for Nanoscale Applications

    DEFF Research Database (Denmark)

    Villadsen, Klaus

    Bio-conjugates for Nanoscale Applications is the title of this thesis, which covers three different projects in chemical bio-conjugation research, namely synthesis and applications of: Lipidated fluorescent peptides, carbohydrate oxime-azide linkers and N-aryl O-R2 oxyamine derivatives. Lipidated...

  8. Powdered Hexagonal Boron Nitride Reducing Nanoscale Wear

    Science.gov (United States)

    Chkhartishvili, L.; Matcharashvili, T.; Esiava, R.; Tsagareishvili, O.; Gabunia, D.; Margiev, B.; Gachechiladze, A.

    2013-05-01

    A morphology model is suggested for nano-powdered hexagonal boron nitride that can serve as an effective solid additive to liquid lubricants. It allows to estimate the specific surface, that is a hard-to-measure parameter, based on average size of powder particles. The model can be used also to control nanoscale wear processes.

  9. Nanofabrication of Hybrid Optoelectronic Devices

    Science.gov (United States)

    Dibos, Alan Michael

    The material requirements for optoelectronic devices can vary dramatically depending on the application. Often disparate material systems need to be combined to allow for full device functionality. At the nanometer scale, this can often be challenging because of the inherent chemical and structural incompatibilities of nanofabrication. This dissertation concerns the integration of seemingly dissimilar materials into hybrid optoelectronic devices for photovoltaic, plasmonic, and photonic applications. First, we show that combining a single strip of conjugated polymer and inorganic nanowire can yield a nanoscale solar cell, and modeling of optical absorption and exciton diffusion in this device can provide insight into the efficiency of charge separation. Second, we use an on-chip nanowire light emitting diode to pump a colloidal quantum dot coupled to a silver waveguide. The resulting device is an electro-optic single plasmon source. Finally, we transfer diamond waveguides onto near-field avalanche photodiodes fabricated from GaAs. Embedded in the diamond waveguides are nitrogen vacancy color centers, and the mapping of emission from these single-photon sources is demonstrated using our on-chip detectors, eliminating the need for external photodetectors on an optical table. These studies show the promise of hybrid optoelectronic devices at the nanoscale with applications in alternative energy, optical communication, and quantum optics.

  10. Method and system for nanoscale plasma processing of objects

    Science.gov (United States)

    Oehrlein, Gottlieb S.; Hua, Xuefeng; Stolz, Christian

    2008-12-30

    A plasma processing system includes a source of plasma, a substrate and a shutter positioned in close proximity to the substrate. The substrate/shutter relative disposition is changed for precise control of substrate/plasma interaction. This way, the substrate interacts only with a fully established, stable plasma for short times required for nanoscale processing of materials. The shutter includes an opening of a predetermined width, and preferably is patterned to form an array of slits with dimensions that are smaller than the Debye screening length. This enables control of the substrate/plasma interaction time while avoiding the ion bombardment of the substrate in an undesirable fashion. The relative disposition between the shutter and the substrate can be made either by moving the shutter or by moving the substrate.

  11. Interfacial Effects on Nanoscale Wrinkling in Gold-Covered Polystyrene.

    Science.gov (United States)

    Chapman, Craig T; Paci, Jeffrey T; Lee, Won-Kyu; Engel, Clifford J; Odom, Teri W; Schatz, George C

    2016-09-21

    Nanoscale wrinkling on the surfaces of polymer-based materials can be precisely controlled by depositing thin metal films of varying thicknesses. The deposition of these films fundamentally alters the mechanical properties of the substrates in ways that are not simply described using traditional continuum mechanical frameworks. In particular, we find, by modeling within a finite element analysis approach, that the very act of depositing a metal film may alter the Young's modulus of the polymer substrate to depths of up to a few hundred nanometers, creating a modified interfacial skin layer. We find that simulated wrinkle patterns reproduce the experimentally observed features only when the modulus of this surface layer varies by more than ∼500 nm and is described using a sigmoidal gradient multiplier.

  12. Probing Nanoscale Electronic and Magnetic Interaction with Scanning Tunneling Spectroscopy

    DEFF Research Database (Denmark)

    Bork, Jakob

    This thesis is concerned with fundamental research into electronic and magnetic interaction on the nanoscale. From small metallic and magnetic islands and layers to single atoms. The research revolves around magnetic interaction probed through the spectroscopic capabilities of the scanning....... This is related to research in correlated electron materials such as studies of phase transitions in heavy fermion compounds and magnetic interaction in spintronic research. The capping of cobalt islands on Cu(111) with silver is investigated with STM and photoemission spectroscopy. It is shown that at low...... coverage the silver preferably nucleates on top of the bilayer high cobalt islands compared to directly on the Cu(111) substrate. Furthermore, the silver forms a combination of a reconstruction and a Moire pattern which is investigated with low-energy electron diraction and spectroscopic STM mapping at 6...

  13. Physical IC debug ─ backside approach and nanoscale challenge

    Directory of Open Access Journals (Sweden)

    U. Kerst

    2008-05-01

    Full Text Available Physical analysis for IC functionality in submicron technologies requires access through chip backside. Based upon typical global backside preparation with 50–100 µm moderate silicon thickness remaining, a state of the art of the analysis techniques available for this purpose is presented and evaluated for functional analysis and layout pattern resolution potential. A circuit edit technique valid for nano technology ICs, is also presented that is based upon the formation of local trenches using the bottom of Shallow Trench Isolation (STI as endpoint for Focused Ion Beam (FIB milling. As a derivative from this process, a locally ultra thin silicon device can be processed, creating a back surface as work bench for breakthrough applications of nanoscale analysis techniques to a fully functional circuit through chip backside. Several applications demonstrate the power and potential of this new approach.

  14. Trends in electrocatalysis : from extended to nanoscale surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Stamenkovic, V. R.; Mun, B. S.; Arenz, M.; Mayrhofer, K. J. J.; Lucas, C. A.; Wang, G.; Ross, P. N.; Markovic, N. M.; Materials Science Division; Lawrence Berkeley Nat. Lab.; Technical Univ. Munich; Univ. of Liverpool; Univ. of South Carolina

    2007-01-01

    One of the key objectives in fuel-cell technology is to improve and reduce Pt loading as the oxygen-reduction catalyst. Here, we show a fundamental relationship in electrocatalytic trends on Pt{sub 3}M (M=Ni, Co, Fe, Ti, V) surfaces between the experimentally determined surface electronic structure (the d-band centre) and activity for the oxygen-reduction reaction. This relationship exhibits 'volcano-type' behavior, where the maximum catalytic activity is governed by a balance between adsorption energies of reactive intermediates and surface coverage by spectator (blocking) species. The electrocatalytic trends established for extended surfaces are used to explain the activity pattern of Pt{sub 3}M nanocatalysts as well as to provide a fundamental basis for the catalytic enhancement of cathode catalysts. By combining simulations with experiments in the quest for surfaces with desired activity, an advanced concept in nanoscale catalyst engineering has been developed.

  15. High performance carbon nanotube--polymer nanofiber hybrid fabrics.

    Science.gov (United States)

    Yildiz, Ozkan; Stano, Kelly; Faraji, Shaghayegh; Stone, Corinne; Willis, Colin; Zhang, Xiangwu; Jur, Jesse S; Bradford, Philip D

    2015-10-28

    Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m(-2) exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.

  16. Liquid Spreading under Nanoscale Confinement

    Science.gov (United States)

    Checco, Antonio

    2009-03-01

    Dynamic atomic force microscopy in the noncontact regime is used to study the morphology of a nonvolatile liquid (squalane) as it spreads along wettable nanostripes embedded in a nonwettable surface. Results show that the liquid profile depends on the amount of lateral confinement imposed by the nanostripes, and it is truncated at the microscopic contact line in good qualitative agreement with classical mesoscale hydrodynamics. However, the width of the contact line is found to be significantly larger than expected theoretically. This behavior may originate from small chemical inhomogeneity of the patterned stripes as well as from thermal fluctuations of the contact line.

  17. Printable nanoscale metal ring arrays via vertically aligned carbon nanotube platforms.

    Science.gov (United States)

    Lee, Sang Ho; Yoon, Seungha; Jeong, Huisu; Han, Mingu; Choi, Sung Mook; Kim, Jong Guk; Park, Ji-Woong; Jung, Gun Young; Cho, Beong Ki; Kim, Won Bae

    2013-11-01

    This paper reports a novel and efficient strategy for fabricating sub-100 nm metal ring arrays using a simple printing process. Vertically aligned carbon nanotubes that are supported by hexagonally ordered channels of alumina matrices are used as a stamp to print nanoscale ring patterns, which is a very unique stamping platform that has never been reported. Using this strategy, uniform nanoring patterns of various metals can be directly printed onto a wide range of substrate surfaces under ambient conditions. Significantly, the size and interval of the printed nanorings can be systematically tuned by controlling the ring-shaped tip dimensions of the pristine stamps. An advanced example of these printable nanoscale metal ring arrays is explicitly embodied in this work by investigation of the plasmon resonances of metal nanorings with different sizes and intervals.

  18. Energy Efficiency Comparison between Hydraulic Hybrid and Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Jia-Shiun Chen

    2015-05-01

    Full Text Available Conventional vehicles tend to consume considerable amounts of fuel, which generates exhaust gases and environmental pollution during intermittent driving cycles. Therefore, prospective vehicle designs favor improved exhaust emissions and energy consumption without compromising vehicle performance. Although pure electric vehicles feature high performance and low pollution characteristics, their limitations are their short driving range and high battery costs. Hybrid electric vehicles (HEVs are comparatively environmentally friendly and energy efficient, but cost substantially more compared with conventional vehicles. Hydraulic hybrid vehicles (HHVs are mainly operated using engines, or using alternate combinations of engine and hydraulic power sources while vehicles accelerate. When the hydraulic system accumulator is depleted, the conventional engine reengages; concurrently, brake-regenerated power is recycled and reused by employing hydraulic motor–pump modules in circulation patterns to conserve fuel and recycle brake energy. This study adopted MATLAB Simulink to construct complete HHV and HEV models for backward simulations. New European Driving Cycles were used to determine the changes in fuel economy. The output of power components and the state-of-charge of energy could be retrieved. Varying power component models, energy storage component models, and series or parallel configurations were combined into seven different vehicle configurations: the conventional manual transmission vehicle, series hybrid electric vehicle, series hydraulic hybrid vehicle, parallel hybrid electric vehicle, parallel hydraulic hybrid vehicle, purely electric vehicle, and hydraulic-electric hybrid vehicle. The simulation results show that fuel consumption was 21.80% lower in the series hydraulic hybrid vehicle compared to the series hybrid electric vehicle; additionally, fuel consumption was 3.80% lower in the parallel hybrid electric vehicle compared to the

  19. EDITORIAL: Big science at the nanoscale Big science at the nanoscale

    Science.gov (United States)

    Reed, Mark

    2009-10-01

    In 1990, the journal Nanotechnology was the first academic publication dedicated to disseminating the results of research in what was then a new field of scientific endeavour. To celebrate the 20th volume of Nanotechnology, we are publishing a special issue of top research papers covering all aspects of this multidisciplinary science, including biology, electronics and photonics, quantum phenomena, sensing and actuating, patterning and fabrication, material synthesis and the properties of nanomaterials. In the early 1980s, scanning probe microscopes brought the concepts of matter and interactions at the nanoscale into visual reality, and hastened a flurry of activity in the burgeoning new field of nanoscience. Twenty years on and nanotechnology has truly come of age. The ramifications are pervasive throughout daily life in communication, health care and entertainment technology. For example, DVDs have now consigned videotapes to the ark and mobile phones are as prevalent as house keys, and these technologies already look set to be superseded by internet phones and Blu-Ray discs. Nanotechnology has been in the unique position of following the explosive growth of this discipline from its outset. The surge of activity in the field is notable in the number of papers published by the journal each year, which has skyrocketed. The journal is now published weekly, publishing over 1400 articles a year. What is more, the quality of these articles is also constantly improving; the average number of citations to articles within two years of publication, quantified by the ISI impact factor, continues to increase every year. The rate of activity in the field shows no signs of slowing down, as is evident from the wealth of great research published each week. The aim of the 20th volume special issue is to present some of the very best and most recent research in many of the wide-ranging fields covered by the journal, a celebration of the present state of play in nanotechnology and

  20. Self-forming nanoscale devices

    Directory of Open Access Journals (Sweden)

    Lars Samuelson

    2003-10-01

    The top-down approach limits the dimensions of devices to what is technically achievable using lithography. This is the means by which patterns can be drawn, either in stone as the Vikings did when they carved messages into granite, or into Si as the electronics industry does today to build integrated circuits. Lithographic techniques can create device features as narrow as 130 nm and the industry sees the road ahead pretty well drawn up for line-widths down to ∼50 nm. This continued progress does not come without a price; the cost of new fabs is growing extremely fast, at a pace that may limit continued progress, simply because devices and circuits become too expensive to be economically viable.

  1. Polymer crystallization as a tool to pattern hybrid nanostructures: growth of 12 nm ZnO arrays in poly(3-hexylthiophene).

    Science.gov (United States)

    Saberi Moghaddam, Reza; Huettner, Sven; Vaynzof, Yana; Ducati, Caterina; Divitini, Giorgio; Lohwasser, Ruth H; Musselman, Kevin P; Sepe, Alessandro; Scherer, Maik R J; Thelakkat, Mukundan; Steiner, Ullrich; Friend, Richard H

    2013-09-11

    Well-ordered hybrid materials with a 10 nm length scale are highly desired. We make use of the natural length scale (typically 10-15 nm) of the alternating crystalline and amorphous layers that are generally found in semicrystalline polymers to direct the growth of a semiconducting metal oxide. This approach is exemplified with the growth of ZnO within a carboxylic acid end-functionalized poly(3-hexylthiophene) (P3HT-COOH). The metal-oxide precursor vapors diffuse into the amorphous parts of the semicrystalline polymer so that sheets of ZnO up to 0.5 μm in size can be grown. This P3HT-ZnO nanostructure further functions as a donor-acceptor photovoltaic system, with length scales appropriate for charge photogeneration.

  2. Far-field nanoscale infrared spectroscopy of vibrational fingerprints of molecules with graphene plasmons

    Science.gov (United States)

    Hu, Hai; Yang, Xiaoxia; Zhai, Feng; Hu, Debo; Liu, Ruina; Liu, Kaihui; Sun, Zhipei; Dai, Qing

    2016-01-01

    Infrared spectroscopy, especially for molecular vibrations in the fingerprint region between 600 and 1,500 cm−1, is a powerful characterization method for bulk materials. However, molecular fingerprinting at the nanoscale level still remains a significant challenge, due to weak light–matter interaction between micron-wavelengthed infrared light and nano-sized molecules. Here we demonstrate molecular fingerprinting at the nanoscale level using our specially designed graphene plasmonic structure on CaF2 nanofilm. This structure not only avoids the plasmon–phonon hybridization, but also provides in situ electrically-tunable graphene plasmon covering the entire molecular fingerprint region, which was previously unattainable. In addition, undisturbed and highly confined graphene plasmon offers simultaneous detection of in-plane and out-of-plane vibrational modes with ultrahigh detection sensitivity down to the sub-monolayer level, significantly pushing the current detection limit of far-field mid-infrared spectroscopies. Our results provide a platform, fulfilling the long-awaited expectation of high sensitivity and selectivity far-field fingerprint detection of nano-scale molecules for numerous applications. PMID:27460765

  3. Far-field nanoscale infrared spectroscopy of vibrational fingerprints of molecules with graphene plasmons

    Science.gov (United States)

    Hu, Hai; Yang, Xiaoxia; Zhai, Feng; Hu, Debo; Liu, Ruina; Liu, Kaihui; Sun, Zhipei; Dai, Qing

    2016-07-01

    Infrared spectroscopy, especially for molecular vibrations in the fingerprint region between 600 and 1,500 cm-1, is a powerful characterization method for bulk materials. However, molecular fingerprinting at the nanoscale level still remains a significant challenge, due to weak light-matter interaction between micron-wavelengthed infrared light and nano-sized molecules. Here we demonstrate molecular fingerprinting at the nanoscale level using our specially designed graphene plasmonic structure on CaF2 nanofilm. This structure not only avoids the plasmon-phonon hybridization, but also provides in situ electrically-tunable graphene plasmon covering the entire molecular fingerprint region, which was previously unattainable. In addition, undisturbed and highly confined graphene plasmon offers simultaneous detection of in-plane and out-of-plane vibrational modes with ultrahigh detection sensitivity down to the sub-monolayer level, significantly pushing the current detection limit of far-field mid-infrared spectroscopies. Our results provide a platform, fulfilling the long-awaited expectation of high sensitivity and selectivity far-field fingerprint detection of nano-scale molecules for numerous applications.

  4. Real-Time Nanoscale Open-Circuit Voltage Dynamics of Perovskite Solar Cells.

    Science.gov (United States)

    Garrett, Joseph L; Tennyson, Elizabeth M; Hu, Miao; Huang, Jinsong; Munday, Jeremy N; Leite, Marina S

    2017-04-12

    Hybrid organic-inorganic perovskites based on methylammonium lead (MAPbI3) are an emerging material with great potential for high-performance and low-cost photovoltaics. However, for perovskites to become a competitive and reliable solar cell technology their instability and spatial variation must be understood and controlled. While the macroscopic characterization of the devices as a function of time is very informative, a nanoscale identification of their real-time local optoelectronic response is still missing. Here, we implement a four-dimensional imaging method through illuminated heterodyne Kelvin probe force microscopy to spatially (perovskite solar cells in a low relative humidity environment. Local open-circuit voltage (Voc) images show nanoscale sites with voltage variation >300 mV under 1-sun illumination. Surprisingly, regions of voltage that relax in seconds and after several minutes consistently coexist. Time-dependent changes of the local Voc are likely due to intragrain ion migration and are reversible at low injection level. These results show for the first time the real-time transient behavior of the Voc in perovskite solar cells at the nanoscale. Understanding and controlling the light-induced electrical changes that affect device performance are critical to the further development of stable perovskite-based solar technologies.

  5. Micro- and nano-scale optoelectronic devices using vanadium dioxide

    Science.gov (United States)

    Joushaghani, Arash

    Miniaturization has the potential to reduce the size, cost, and power requirements of active optical devices. However, implementing (sub)wavelength-scale electro-optic switches with high efficiency, low insertion loss, and high extinction ratios remains challenging due to their small active volumes. Here, we use the insulator-metal phase transition of vanadium dioxide (VO2), which exhibits a large and reversible change in the refractive index across the phase transition to demonstrate compact, broadband, and efficient switches and photodetectors with record-setting characteristics. We begin by analyzing the electrical and optical properties of VO2 thin films across the phase transition and discuss the fabrication processes that yield micron- and nano-scale VO2 devices. We then demonstrate a surface plasmon thermo-optic switch, which achieves an extinction ratio of 10 dB in a 5 um long device, a record for plasmonic devices. The switch operates over a 100 nm optical bandwidth, and exhibits a thermally limited switching time of 40 mus. We investigate the current and voltage induced switching of VO2 in nano-gap junctions and show optical switching times as short as 20 ns. The two terminal VO2 junctions are incorporated in a silicon photonics platform to yield silicon-VO2 hybrid waveguide devices with a record extinction ratio of 12 dB in a 1 mum long device. In photodetector mode, the devices exhibit a nonlinear responsivity greater than 12 A/W for optical powers less than 1 muW. This device is the smallest electrically controlled and integrated switch and photodetector capable of achieving extinction ratios > 10 dB/mum. We finally investigate the ultra-fast thermal heating in gold nano-apertures and demonstrate that electron heating can change the gold lattice temperature by 300 K in tens of picoseconds. These nano-apertures can be hybridized with VO2 to demonstrate high extinction and ultrafast optical switches.

  6. Three dimensional self-assembly at the nanoscale

    Science.gov (United States)

    Gracias, D. H.

    2013-05-01

    At the nanoscale, three dimensional manipulation and assembly becomes extremely challenging and also cost prohibitive. Self-assembly provides an attractive and possibly the only highly parallel methodology to structure truly three dimensional patterned materials and devices at this size scale for applications in electronics, optics, robotics and medicine. This is a concise review along with a perspective of an important and exciting field in nanotechnology and is related to a Nanoengineering Pioneer Award that I received at this SPIE symposium for my contributions to the 3D selfassembly of nanostructures. I detail a historical account of 3D self-assembly and outline important developments in this area which is put into context with the larger research areas of 3D nanofabrication, assembly and nanomanufacturing. A focus in this review is on our work as it relates to the self-assembly with lithographically patterned units; this approach provides a means for heterogeneous integration of periodic, curved and angled nanostructures with precisely defined three dimensional patterns.

  7. CMOS compatible nanoscale nonvolatile resistance switching memory.

    Science.gov (United States)

    Jo, Sung Hyun; Lu, Wei

    2008-02-01

    We report studies on a nanoscale resistance switching memory structure based on planar silicon that is fully compatible with CMOS technology in terms of both materials and processing techniques employed. These two-terminal resistance switching devices show excellent scaling potential well beyond 10 Gb/cm2 and exhibit high yield (99%), fast programming speed (5 ns), high on/off ratio (10(3)), long endurance (10(6)), retention time (5 months), and multibit capability. These key performance metrics compare favorably with other emerging nonvolatile memory techniques. Furthermore, both diode-like (rectifying) and resistor-like (nonrectifying) behaviors can be obtained in the device switching characteristics in a controlled fashion. These results suggest that the CMOS compatible, nanoscale Si-based resistance switching devices may be well suited for ultrahigh-density memory applications.

  8. Programmed assembly of nanoscale structures using peptoids.

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Jianhua (University of the Pacific, Stockton, CA); Russell, Scott (California State University, Stanislaus, Turlock, CA); Morishetti, Kiran (University of the Pacific, Stockton, CA); Robinson, David B.; Zuckermann, Ronald N. (Lawrence Berkeley National Laboratory, Berkeley, CA); Buffleben, George M.; Hjelm, Rex P. (Los Alamos National Laboratory, Los Alamos, NM); Kent, Michael Stuart (Sandia National Laboratories, Albuquerque, NM)

    2011-02-01

    Sequence-specific polymers are the basis of the most promising approaches to bottom-up programmed assembly of nanoscale materials. Examples include artificial peptides and nucleic acids. Another class is oligo(N-functional glycine)s, also known as peptoids, which permit greater sidegroup diversity and conformational control, and can be easier to synthesize and purify. We have developed a set of peptoids that can be used to make inorganic nanoparticles more compatible with biological sequence-specific polymers so that they can be incorporated into nucleic acid or other biologically based nanostructures. Peptoids offer degrees of modularity, versatility, and predictability that equal or exceed other sequence-specific polymers, allowing for rational design of oligomers for a specific purpose. This degree of control will be essential to the development of arbitrarily designed nanoscale structures.

  9. Controlling carrier dynamics at the nanoscale

    Science.gov (United States)

    Cánovas, Enrique; Bonn, Mischa

    2016-10-01

    This Special issue is motivated by the occasion of the International Conference on Charge Carrier Dynamics at the Nanoscale (CCDNano), held in Santiago de Compostela (Spain) in September 2015. As chairs for the CCDNano meeting, we aimed at bringing together experts from different scientific fields in order to trigger interdisciplinary discussions and collaborations; the ultimate goal of the conference was to serve as a platform to advance and help unifying methodologies and theories from different research sub-fields. We also aimed at a deeper understanding of charge dynamics to contribute to the development of improved or novel nanostructured devices. This special issue keeps that spirit, and intends to provide an overview of ongoing research efforts regarding charge carrier dynamics at the nanoscale.

  10. Scanning nanoscale multiprobes for conductivity measurements

    DEFF Research Database (Denmark)

    Bøggild, Peter; Hansen, Torben Mikael; Kuhn, Oliver;

    2000-01-01

    We report fabrication and measurements with two- and four-point probes with nanoscale dimensions, for high spatial resolution conductivity measurements on surfaces and thin films. By combination of conventional microfabrication and additive three-dimensional nanolithography, we have obtained...... electrode spacings down to 200 nm. At the tips of four silicon oxide microcantilevers, narrow carbon tips are grown in converging directions and subsequently coated with a conducting layer. The probe is placed in contact with a conducting surface, whereby the electrode resistance can be determined....... The nanoelectrodes withstand considerable contact force before breaking. The probe offers a unique possibility to position the voltage sensors, as well as the source and drain electrodes in areas of nanoscale dimensions. ©2000 American Institute of Physics....

  11. MEMS & microsystems design, manufacture, and nanoscale engineering

    CERN Document Server

    Hsu, Tai-Ran

    2008-01-01

    A bestselling MEMS text...now better than ever. An engineering design approach to Microelectromechanical Systems, MEMS and Microsystems remains the only available text to cover both the electrical and the mechanical aspects of the technology. In the five years since the publication of the first edition, there have been significant changes in the science and technology of miniaturization, including microsystems technology and nanotechnology. In response to the increasing needs of engineers to acquire basic knowledge and experience in these areas, this popular text has been carefully updated, including an entirely new section on the introduction of nanoscale engineering. Following a brief introduction to the history and evolution of nanotechnology, the author covers the fundamentals in the engineering design of nanostructures, including fabrication techniques for producing nanoproducts, engineering design principles in molecular dynamics, and fluid flows and heat transmission in nanoscale substances.

  12. Nanoscale plasmonic stamp lithography on silicon.

    Science.gov (United States)

    Liu, Fenglin; Luber, Erik J; Huck, Lawrence A; Olsen, Brian C; Buriak, Jillian M

    2015-02-24

    Nanoscale lithography on silicon is of interest for applications ranging from computer chip design to tissue interfacing. Block copolymer-based self-assembly, also called directed self-assembly (DSA) within the semiconductor industry, can produce a variety of complex nanopatterns on silicon, but these polymeric films typically require transformation into functional materials. Here we demonstrate how gold nanopatterns, produced via block copolymer self-assembly, can be incorporated into an optically transparent flexible PDMS stamp, termed a plasmonic stamp, and used to directly functionalize silicon surfaces on a sub-100 nm scale. We propose that the high intensity electric fields that result from the localized surface plasmons of the gold nanoparticles in the plasmonic stamps upon illumination with low intensity green light, lead to generation of electron-hole pairs in the silicon that drive spatially localized hydrosilylation. This approach demonstrates how localized surface plasmons can be used to enable functionalization of technologically relevant surfaces with nanoscale control.

  13. Chemistry of Nanoscale Semiconductor Clusters

    CERN Document Server

    Pan, J; Ramakrishna, M V; Pan, Jun; Bahel, Atul; Ramakrishna, Mushti V.

    1995-01-01

    The ground state structures of small silicon clusters are determined through exhaustive tight-binding molecular dynamics simulation studies. These simulations revealed that \\Si{11} is an icosahedron with one missing cap, \\Si{12} is a complete icosahedron, \\Si{13} is a surface capped icosahedron, \\Si{14} is a 4-4-4 layer structure with two caps, \\Si{15} is a 1-5-3-5-1 layer structure, and \\Si{16} is a partially closed cage consisting of five-membered rings. The characteristic feature of these clusters is that they are all surface. Smalley and co-workers discovered that chemisorption reactivities of silicon clusters vary over three orders of magnitude as a function of cluster size. In particular, they found that \\Si{33}, \\Si{39}, and \\Si{45} clusters are least reactive towards various reagents compared to their immediate neighbors in size. We provide insights into this observed reactivity pattern through our stuffed fullerene model. This structural model consists of bulk-like core of five atoms surrounded by fu...

  14. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2013-12-23

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  15. DOE - BES Nanoscale Science Research Centers (NSRCs)

    Energy Technology Data Exchange (ETDEWEB)

    Beecher, Cathy Jo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-14

    These are slides from a powerpoint shown to guests during tours of Center for Integrated Nanotechnologies (CINT) at Los Alamos National Laboratory. It shows the five DOE-BES nanoscale science research centers (NSRCs), which are located at different national laboratories throughout the country. Then it goes into detail specifically about the Center for Integrated Nanotechnologies at LANL, including statistics on its user community and CINT's New Mexico industrial users.

  16. Infochemistry Information Processing at the Nanoscale

    CERN Document Server

    Szacilowski, Konrad

    2012-01-01

    Infochemistry: Information Processing at the Nanoscale, defines a new field of science, and describes the processes, systems and devices at the interface between chemistry and information sciences. The book is devoted to the application of molecular species and nanostructures to advanced information processing. It includes the design and synthesis of suitable materials and nanostructures, their characterization, and finally applications of molecular species and nanostructures for information storage and processing purposes. Divided into twelve chapters; the first three chapters serve as an int

  17. Nanoscale molecularly imprinted polymers and method thereof

    Science.gov (United States)

    Hart, Bradley R.; Talley, Chad E.

    2008-06-10

    Nanoscale molecularly imprinted polymers (MIP) having polymer features wherein the size, shape and position are predetermined can be fabricated using an xy piezo stage mounted on an inverted microscope and a laser. Using an AMF controller, a solution containing polymer precursors and a photo initiator are positioned on the xy piezo and hit with a laser beam. The thickness of the polymeric features can be varied from a few nanometers to over a micron.

  18. Current-Induced Effects in Nanoscale Conductors

    OpenAIRE

    2005-01-01

    We present an overview of current-induced effects in nanoscale conductors with emphasis on their description at the atomic level. In particular, we discuss steady-state current fluctuations, current-induced forces, inelastic scattering and local heating. All of these properties are calculated in terms of single-particle wavefunctions computed using a scattering approach within the static density-functional theory of many-electron systems. Examples of current-induced effects in atomic and mole...

  19. Nanoscale thermal transport. II. 2003–2012

    Energy Technology Data Exchange (ETDEWEB)

    Cahill, David G., E-mail: d-cahill@illinois.edu; Braun, Paul V. [Department of Materials Science and Engineering and the Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States); Chen, Gang [Department of Mechanical Engineering, MIT, Cambridge, Massachusetts 02139 (United States); Clarke, David R. [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Fan, Shanhui [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Goodson, Kenneth E. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Keblinski, Pawel [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); King, William P. [Department of Mechanical Sciences and Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Mahan, Gerald D. [Department of Physics, Penn State University, University Park, Pennsylvania 16802 (United States); Majumdar, Arun [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Maris, Humphrey J. [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States); Phillpot, Simon R. [Department of Materials Science and Engineering, University of Florida, Gainseville, Florida 32611 (United States); Pop, Eric [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Shi, Li [Department of Mechanical Engineering, University of Texas, Autin, Texas 78712 (United States)

    2014-03-15

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ∼1 nm, the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and

  20. Nanoscale Science, Engineering and Technology Research Directions

    Energy Technology Data Exchange (ETDEWEB)

    Lowndes, D. H.; Alivisatos, A. P.; Alper, M.; Averback, R. S.; Jacob Barhen, J.; Eastman, J. A.; Imre, D.; Lowndes, D. H.; McNulty, I.; Michalske, T. A.; Ho, K-M; Nozik, A. J.; Russell, T. P.; Valentin, R. A.; Welch, D. O.; Barhen, J.; Agnew, S. R.; Bellon, P.; Blair, J.; Boatner, L. A.; Braiman, Y.; Budai, J. D.; Crabtree, G. W.; Feldman, L. C.; Flynn, C. P.; Geohegan, D. B.; George, E. P.; Greenbaum, E.; Grigoropoulos, C.; Haynes, T. E.; Heberlein, J.; Hichman, J.; Holland, O. W.; Honda, S.; Horton, J. A.; Hu, M. Z.-C.; Jesson, D. E.; Joy, D. C.; Krauss, A.; Kwok, W.-K.; Larson, B. C.; Larson, D. J.; Likharev, K.; Liu, C. T.; Majumdar, A.; Maziasz, P. J.; Meldrum, A.; Miller, J. C.; Modine, F. A.; Pennycook, S. J.; Pharr, G. M.; Phillpot, S.; Price, D. L.; Protopopescu, V.; Poker, D. B.; Pui, D.; Ramsey, J. M.; Rao, N.; Reichl, L.; Roberto, J.; Saboungi, M-L; Simpson, M.; Strieffer, S.; Thundat, T.; Wambsganss, M.; Wendleken, J.; White, C. W.; Wilemski, G.; Withrow, S. P.; Wolf, D.; Zhu, J. H.; Zuhr, R. A.; Zunger, A.; Lowe, S.

    1999-01-01

    This report describes important future research directions in nanoscale science, engineering and technology. It was prepared in connection with an anticipated national research initiative on nanotechnology for the twenty-first century. The research directions described are not expected to be inclusive but illustrate the wide range of research opportunities and challenges that could be undertaken through the national laboratories and their major national scientific user facilities with the support of universities and industry.

  1. Attosecond physics at a nanoscale metal tip

    Directory of Open Access Journals (Sweden)

    Lemell Christoph

    2013-03-01

    Full Text Available With few-cycle laser oscillator pulses at 800 nm we observe strong-field and attosecond physics phenomena in electron spectra recorded at a nanoscale tungsten tip. We observe the rescattering plateau as well as a strong carrier-envelope phase dependence of the spectra. We model the results with the semiclassical three-step model as well as with time-dependent density functional theory.

  2. Fourth International Conference on Nanoscale Magnetism

    CERN Document Server

    Aktas, Bekir; Advances in Nanoscale Magnetism

    2009-01-01

    The book aims to provide an overview of recent progress in the understanding of magnetic properties in nanoscale through recent results of various theoretical and experimental investigations. The papers describe a wide range of physical aspects, together with theoretical and experimental methods. It is of central interest to researchers and specialists in magnetism and magnetic materials science, both in academic and industrial research, as well as advanced students.

  3. Imprinting nanoporous alumina patterns into the magneto-transport of oxide superconductors.

    Science.gov (United States)

    Villegas, J E; Swiecicki, I; Bernard, R; Crassous, A; Briatico, J; Wolf, T; Bergeal, N; Lesueur, J; Ulysse, C; Faini, G; Hallet, X; Piraux, L

    2011-02-18

    We used oxygen ion irradiation to transfer the nanoscale pattern of a porous alumina mask into high-T(C) superconducting thin films. This causes a nanoscale spatial modulation of superconductivity and strongly affects the magneto-transport below T(C), which shows a series of periodic oscillations reminiscent of the Little-Parks effect in superconducting wire networks. This irradiation technique could be extended to other oxide materials in order to induce ordered nanoscale phase segregation.

  4. EDITORIAL: Mastering matter at the nanoscale Mastering matter at the nanoscale

    Science.gov (United States)

    Forchel, Alfred

    2009-10-01

    In the early 1980s, the development of scanning probe techniques gave scientists a titillating view of surfaces with nanometre resolution, igniting activity in research at the nanoscale. Images at unprecedented resolution were unveiled with the aid of various types of nanosized tips, including the scanning tunnelling (Binnig G, Rohrer H, Gerber C and Weibel E 1982 Appl. Phys. Lett. 40 178-80) the atomic force (Binnig G, Quate C F and Gerber C 1986 Phys. Rev. Lett. 56 930-3) and the near-field scanning microscopes (Dürig U, Pohl D W and Rohner F 1986 J. Appl. Phys. 59 3318-27). From the magnitude of tunnelling currents between conductive surfaces and van der Waals forces between dielectrics to the non-propagating evanescent fields at illuminated surfaces, a range of signal responses were harnessed enabling conductive, dielectric and even biological systems to be imaged. But it may be argued that it was the ability to manipulate matter at the nanoscale that really empowered nanotechnology. From the inception of the scanning probe revolution, these probes used to image nanostructures were also discovered to be remarkable tools for the manipulation of nanoparticles. Insights into the mechanism behind such processes were reported by a team of researchers at UCLA over ten years ago in 1998 (Baur C et al 1998 Nanotechnology 9 360-4). In addition, lithography and etching methods of patterning continue to evolve into ever more sophisticated techniques for exerting design over the structure of matter at the nanoscale. These so-called top-down methods, such as photolithography, electron-beam lithography and nanoimprint lithography, now provide control over features with a resolution of a few nanometres. Bottom-up fabrication techniques that exploit the self-assembly of constituents into desired structures have also stimulated extensive research. These techniques, such as the electrochemically assembled quantum-dot arrays reported by a team of US reasearchers over ten years

  5. Nanoscale piezoelectric vibration energy harvester design

    Directory of Open Access Journals (Sweden)

    Hamid Reza Foruzande

    2017-09-01

    Full Text Available Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton’s principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

  6. Resonant Effects in Nanoscale Bowtie Apertures

    Science.gov (United States)

    Ding, Li; Qin, Jin; Guo, Songpo; Liu, Tao; Kinzel, Edward; Wang, Liang

    2016-01-01

    Nanoscale bowtie aperture antennas can be used to focus light well below the diffraction limit with extremely high transmission efficiencies. This paper studies the spectral dependence of the transmission through nanoscale bowtie apertures defined in a silver film. A realistic bowtie aperture is numerically modeled using the Finite Difference Time Domain (FDTD) method. Results show that the transmission spectrum is dominated by Fabry-Pérot (F-P) waveguide modes and plasmonic modes. The F-P resonance is sensitive to the thickness of the film and the plasmonic resonant mode is closely related to the gap distance of the bowtie aperture. Both characteristics significantly affect the transmission spectrum. To verify these numerical results, bowtie apertures are FIB milled in a silver film. Experimental transmission measurements agree with simulation data. Based on this result, nanoscale bowtie apertures can be optimized to realize deep sub-wavelength confinement with high transmission efficiency with applications to nanolithography, data storage, and bio-chemical sensing. PMID:27250995

  7. Static electric field enhancement in nanoscale structures

    Science.gov (United States)

    Lepetit, Bruno; Lemoine, Didier; Márquez-Mijares, Maykel

    2016-08-01

    We study the effect of local atomic- and nano-scale protrusions on field emission and, in particular, on the local field enhancement which plays a key role as known from the Fowler-Nordheim model of electronic emission. We study atomic size defects which consist of right angle steps forming an infinite length staircase on a tungsten surface. This structure is embedded in a 1 GV/m ambient electrostatic field. We perform calculations based upon density functional theory in order to characterize the total and induced electronic densities as well as the local electrostatic fields taking into account the detailed atomic structure of the metal. We show how the results must be processed to become comparable with those of a simple homogeneous tungsten sheet electrostatic model. We also describe an innovative procedure to extrapolate our results to nanoscale defects of larger sizes, which relies on the microscopic findings to guide, tune, and improve the homogeneous metal model, thus gaining predictive power. Furthermore, we evidence analytical power laws for the field enhancement characterization. The main physics-wise outcome of this analysis is that limited field enhancement is to be expected from atomic- and nano-scale defects.

  8. Static electric field enhancement in nanoscale structures

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, Bruno, E-mail: bruno.lepetit@irsamc.ups-tlse.fr; Lemoine, Didier, E-mail: didier.lemoine@irsamc.ups-tlse.fr [Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, F-31062 Toulouse (France); CNRS, UMR 5589, F-31062 Toulouse (France); Márquez-Mijares, Maykel, E-mail: mmarquez@instec.cu [Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, F-31062 Toulouse (France); CNRS, UMR 5589, F-31062 Toulouse (France); Instituto Superior de Tecnologías y Ciencias Aplicadas, Avenida Salvador Allende 1110, Quinta de los Molinos, La Habana (Cuba)

    2016-08-28

    We study the effect of local atomic- and nano-scale protrusions on field emission and, in particular, on the local field enhancement which plays a key role as known from the Fowler-Nordheim model of electronic emission. We study atomic size defects which consist of right angle steps forming an infinite length staircase on a tungsten surface. This structure is embedded in a 1 GV/m ambient electrostatic field. We perform calculations based upon density functional theory in order to characterize the total and induced electronic densities as well as the local electrostatic fields taking into account the detailed atomic structure of the metal. We show how the results must be processed to become comparable with those of a simple homogeneous tungsten sheet electrostatic model. We also describe an innovative procedure to extrapolate our results to nanoscale defects of larger sizes, which relies on the microscopic findings to guide, tune, and improve the homogeneous metal model, thus gaining predictive power. Furthermore, we evidence analytical power laws for the field enhancement characterization. The main physics-wise outcome of this analysis is that limited field enhancement is to be expected from atomic- and nano-scale defects.

  9. MEMS-enabled Dip Pen Nanolithography for directed nanoscale deposition and high-throughput nanofabrication

    Science.gov (United States)

    Haaheim, J. R.; Nafday, O. A.; Levesque, T.; Fragala, J.; Shile, R.

    2009-02-01

    Precision nanoscale deposition is a fundamental requirement for nanoscience research, development, and commercial implementation. Dip Pen Nanolithography(R) (DPN) is an inherently additive SPM-based technique which operates under ambient conditions, making it suitable to deposit a wide range of biological and inorganic materials. This technique is fundamentally enabled by a portfolio of MEMS devices tailored for microfluidic ink delivery, directed placement of nanoscale materials via actuated cantilevers, and cm2 tip arrays for high-throughput nanofabrication. Multiplexed deposition of nanoscale materials is a challenging problem, but we have implemented InkWells(TM) to enable selective delivery of ink materials to different tips in multiple probe arrays, while preventing cross-contamination. Active Pens(TM) can take advantage of this, directly place a variety of materials in nanoscale proximity, and do so in a "clean" fashion since the cantilevers can be manipulated in Z. Further, massively parallel two-dimensional nanopatterning with DPN is now commercially available via NanoInk's 2D nano PrintArray(TM), making DPN a highthroughput, flexible and versatile method for precision nanoscale pattern formation. By fabricating 55,000 tip-cantilevers across a 1 cm2 chip, we leverage the inherent versatility of DPN and demonstrate large area surface coverage, routinely achieving throughputs of 3×107 μm2 per hour. Further, we have engineered the device to be easy to use, wire-free, and fully integrated with the NSCRIPTOR's scanner, stage, and sophisticated lithography routines. In this talk we discuss the methods of operating this commercially available device, and subsequent results showing sub-100 nm feature sizes and excellent uniformity (standard deviation portfolio including: 1) rapidly and flexibly generating nanostructures; 2) chemically directed assembly and 3) directly writing biological materials.

  10. Multiscale conformal pattern transfer

    Science.gov (United States)

    Lodewijks, Kristof; Miljkovic, Vladimir; Massiot, Inès; Mekonnen, Addis; Verre, Ruggero; Olsson, Eva; Dmitriev, Alexandre

    2016-06-01

    We demonstrate a method for seamless transfer from a parent flat substrate of basically any lithographic top-down or bottom-up pattern onto essentially any kind of surface. The nano- or microscale patterns, spanning macroscopic surface areas, can be transferred with high conformity onto a large variety of surfaces when such patterns are produced on a thin carbon film, grown on top of a sacrificial layer. The latter allows lifting the patterns from the flat parent substrate onto a water-air interface to be picked up by the host surface of choice. We illustrate the power of this technique by functionalizing broad range of materials including glass, plastics, metals, rough semiconductors and polymers, highlighting the potential applications in in situ colorimetry of the chemistry of materials, anti-counterfeit technologies, biomolecular and biomedical studies, light-matter interactions at the nanoscale, conformal photovoltaics and flexible electronics.

  11. Fast three-dimensional nanoscale metrology in dual-beam FIB-SEM instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Luca, E-mail: luca.repetto@unige.it [Nanomed Labs - Centro Biotecnologie Avanzate and Physics Department, Universita di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Buzio, Renato; Denurchis, Carlo; Firpo, Giuseppe; Piano, Emanuele; Valbusa, Ugo [Nanomed Labs - Centro Biotecnologie Avanzate and Physics Department, Universita di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2009-10-15

    A quantitative surface reconstruction technique has been developed for the geometric characterization of three-dimensional structures by using a combined focused ion beam-scanning electron microscopy (FIB-SEM) instrument. A regular pattern of lines is milled at normal incidence on the sample to be characterized and an image is acquired at a large tilt angle. By analyzing the pattern under the tilted view, a quantitative estimation of surface heights is obtained. The technique has been applied to a test sample and nanoscale resolution has been achieved. The reported results are validated by a comparison with atomic force microscopy measurements.

  12. Fast three-dimensional nanoscale metrology in dual-beam FIB-SEM instrumentation.

    Science.gov (United States)

    Repetto, Luca; Buzio, Renato; Denurchis, Carlo; Firpo, Giuseppe; Piano, Emanuele; Valbusa, Ugo

    2009-10-01

    A quantitative surface reconstruction technique has been developed for the geometric characterization of three-dimensional structures by using a combined focused ion beam-scanning electron microscopy (FIB-SEM) instrument. A regular pattern of lines is milled at normal incidence on the sample to be characterized and an image is acquired at a large tilt angle. By analyzing the pattern under the tilted view, a quantitative estimation of surface heights is obtained. The technique has been applied to a test sample and nanoscale resolution has been achieved. The reported results are validated by a comparison with atomic force microscopy measurements.

  13. Dopamine-assisted rapid fabrication of nanoscale protein arrays by colloidal lithography.

    Science.gov (United States)

    Ogaki, Ryosuke; Bennetsen, Dines T; Bald, Ilko; Foss, Morten

    2012-06-12

    The development of cost-effective methodologies for the precise nanometer-scale positioning of biomolecules permits the low-cost production of various biofunctional devices for a range of biomedical and nanotechnological applications. By combining colloidal lithography and the mussel-inspired multifunctional polydopamine coating, we present a novel parallel benchtop method that allows rapid nanoscale patterning of proteins without the need for electrically powered equipment in the fabrication process. The PDA-immobilized binary nanopattern consisting of BSA surrounded by PLL-g-PEG is fabricated over a large area, and the integrity of the pattern is confirmed using AFM and FM.

  14. Genetic structure in a dynamic baboon hybrid zone corroborates behavioural observations in a hybrid population

    NARCIS (Netherlands)

    Charpentier, M J E; Fontaine, M C; Cherel, E; Renoult, J P; Jenkins, T; Benoit, L; Barthès, N; Alberts, S C; Tung, J

    2012-01-01

    Behaviour and genetic structure are intimately related: mating patterns and patterns of movement between groups or populations influence the movement of genetic variation across the landscape and from one generation to the next. In hybrid zones, the behaviour of the hybridizing taxa can also impact

  15. Brain-like associative learning using a nanoscale non-volatile phase change synaptic device array

    Directory of Open Access Journals (Sweden)

    Sukru Burc Eryilmaz

    2014-07-01

    Full Text Available Recent advances in neuroscience together with nanoscale electronic device technology have resulted in huge interests in realizing brain-like computing hardwares using emerging nanoscale memory devices as synaptic elements. Although there has been experimental work that demonstrated the operation of nanoscale synaptic element at the single device level, network level studies have been limited to simulations. In this work, we demonstrate, using experiments, array level associative learning using phase change synaptic devices connected in a grid like configuration similar to the organization of the biological brain. Implementing Hebbian learning with phase change memory cells, the synaptic grid was able to store presented patterns and recall missing patterns in an associative brain-like fashion. We found that the system is robust to device variations, and large variations in cell resistance states can be accommodated by increasing the number of training epochs. We illustrated the tradeoff between variation tolerance of the network and the overall energy consumption, and found that energy consumption is decreased significantly for lower variation tolerance.

  16. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  17. Pseudovector mesons, hybrids and glueballs

    CERN Document Server

    Burakovsky, L; Burakovsky, Leonid; Page, Philip R.

    2000-01-01

    We consider glueball- (hybrid) meson mixing for the low-lying four pseudovector states. The h_1'(1380) decays dominantly to K*K with some presence in rho pi and omega eta. The newly observed h_1(1600) has a D- to S-wave width ratio to omega eta which does not enable differentiation between a conventional and hybrid meson interpretation. We predict the decay pattern of the isopartner conventional or hybrid meson b_1(1650). A notably narrow s sbar partner h_1'(1810) is predicted.

  18. Nanoscale ripple formation in Co/Si(100) thin films with Ar{sup +} beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Arranz, M A [Fac. Ciencias Quimicas, Universidad de Castilla-La Mancha, Camilo Jose Cela 10, 13071, Ciudad Real (Spain); Colino, Jose M, E-mail: HiguelAngel.Arranz@uclm.e [Instituto de Nanociencia, NanotecnologIa y Materiales Moleculares, UCLM, Campus de la Fabrica de Armas, 45071 Toledo (Spain)

    2010-01-01

    We have investigated the formation of nanoscale ripples on etched Co/Si(100) films with Ar{sup +} beam in grazing incidence. Topography and dimensions of those nanoscale patterns were characterized by means of atomic force microscopy. Polycrystalline cobalt thin films were deposited by d.c. magnetron sputtering onto Si(100) wafers and, later transferred in situ to a process chamber for the production of ripples. Their average width, W{sub d}, and separation between them, i.e. their periodicity {Lambda}, were found to monotonously increase first with the etching time and, finally, reach saturation values for long irradation times (around 30 min). The same Ar{sup +} beam etching applied on thicker Co films resulted in much wider and higher ripples, providing a more defined nanostructure for ulterior uniaxial magnetic anisotropy measurements. These changes in the ripple dimensions on increasing the Co film thickness are discussed in terms of the surface roughness in the as-deposited film.

  19. Modeling and Simulation of Phonon Transport at the Nanoscale for Optimum Thermal Management

    Science.gov (United States)

    Mao, Rui

    mixed bonding force between the Pd and C atoms results in incomplete hybridization of Pd and graphene orbital states at the junction, leading effectively to two phonon interfaces and a larger than expected thermal resistance. Comparison with available experimental data shows good agreement. The result clearly suggests the feasibility of phonon engineering for thermal property optimization at the interface. Transition-metal dichalcogenides (TMDs) MX2 (M=Mo,W; X=S,Se), one of the beyond- graphene two-dimensional semiconductor materials, have emerged as promising candidates due to their distinctive electronic and optical properties. Unlike the zero-bandgap graphene, TMDs have intrinsic bandgaps in the range of 1.1--2.2eV, allowing low off-current for field effect transistors. Thermal transport properties at the metal/MoS2 interfaces are then analyzed by using the atomistic phonon transport model. The considered structures include chemisorbed Sc(0001)/MoS2 and Ru(0001)/MoS 2, physisorbed Au(111)/MoS2, as well as Pd(111)/MoS 2 with intermediate characteristics. Calculated results illustrate a distinctive dependence of thermal transfer on the details of interfacial microstructures. More specifically, the chemisorbed case with a stronger bonding exhibits a generally smaller interfacial thermal resistance than the physisorbed. Comparison between metal/MoS2 and metal/graphene systems suggests that metal/MoS 2 is significantly more resistive. Further examination of lattice dynamics identifies the presence of multiple distinct atomic planes and bonding patterns at the interface as the key origin of the observed large thermal resistance. Finally, since the commensurate-incommensurate transitions are ubiquitous in the fabrication of the 2D material based devices, we have extended our investigation to the thermal/phonon transport across the misoriented 2D nanostructures. An analytical model that can incorporate the atomic level detail as well as being time-efficient is developed for

  20. On-demand rapid transport and stable trapping of nanoparticles of nanoparticles by a hybrid electrothermoplasmonic nanotweezer (Conference Presentation)

    Science.gov (United States)

    Ndukaife, Justus C.; Nnanna, Agbai George Agwu; Kildishev, Alexander V.; Shalaev, Vladimir M.; Wereley, Steven T.; Boltasseva, Alexandra

    2016-09-01

    In plasmon nano-optical tweezers, plasmonic nanoantennas are illuminated to generate highly localized and enhanced electromagnetic field in the vicinity of the nanoantenna. The highly localized and enhanced electromagnetic field creates much stronger optical gradient forces and tighter potential wells for confining particles than in conventional optical tweezers, thus providing a means to trap nanoscale objects and molecules. This approach have been successfully applied for trapping small particles such as protein molecules. However a long standing problem in this field is how to rapidly load the potential well without relying on Brownian diffusion. Conventional design rely on Brownian diffusion to load the trap, which is very slow and could take several minutes to hours depending on the concentration of the nanoscale objects. Furthermore since the plasmonic trapping sites are pre-patterned on a substrate, current plasmonic nanotweezers suffer from the problem of lack of dynamic control over the particles in the trap. Recently we have addressed these challenges by introducing a novel design paradigm known as the Hybrid Electrothermoplasmonic Nanotweezer (HENT)1, where the intrinsic photo-induced heating of the plasmonic nanoantenna is combined with an applied AC electric field to induce a large scale microfluidic flow on-demand. The microfluidic flow enables rapid delivery of suspended nanoparticles to an illuminated plasmonic nanoantenna where they are trapped within a few seconds. In this talk I will discuss the working principle of HENT, as well as HENT-based nanotweezers utilizing alternative plasmonic materials.

  1. Discussion on energy utilization pattern of hydro-photovoltaic hybrid in Ngari area of Tibet%西藏阿里地区水光互补能源利用模式探讨

    Institute of Scientific and Technical Information of China (English)

    李建兵; 罗洋涛; 冯宇

    2016-01-01

    Based on the development and utilization condition of energy and resources and power energy demand in the Ngari area of Tibet, possible power supply schemes were studied. A clean energy utilization hybrid model of a reservoir power station and photovoltaic plant is proposed through comprehensive comparison of power system requirements, operation and maintenance, environmental protection, and economics. The system structure, power generation characteristics, and operation effect of this hydro-photovoltaic hybrid system are analyzed. The results show that the complementary power-generating characteristic of the energy utilization pattern using the reservoir power station and photovoltaic plant is beneficial to photovoltaic power consumption and power network safety operation.%根据西藏阿里地区各类能源资源开发利用条件和系统用电需求,研究可能的能源电力供应方案;通过对各方案在满足电力系统需求、运行维护、环境保护及经济性等方面的综合比较,提出“调节水库电站+光伏”互补运行的清洁能源利用模式,并对该地区水光互补系统的构成、发电特性、运行效果等方面进行分析,结果表明该模式利用调节水库电站与光伏双向互补发电特性有利于并网光伏电能消纳及电网安全稳定运行。

  2. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  3. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  4. Locked Nucleic Acid-Based In Situ Hybridization Reveals miR-7a as a Hypothalamus-Enriched MicroRNA with a Distinct Expression Pattern

    DEFF Research Database (Denmark)

    Herzer, S; Silahtaroglu, A; Meister, B

    2012-01-01

    MicroRNAs (miRNAs) are short (22 nucleotides) non-coding ribonucleic acid (RNA) molecules that post-transcriptionally repress expression of protein-coding genes by binding to 3'-untranslated regions of the target mRNAs. In order to identify miRNAs selectively expressed within the hypothalamus...... present in the hypothalamus, miR-7a, was the only miRNA found to be enriched in the hypothalamus, with low or no expression in other parts of the central nervous system (CNS). Within the hypothalamus, strong miR-7a expression was distinct and restricted to some hypothalamic nuclei and adjacent areas. mi......R-7a expression was particularly prominent in the subfornical organ, suprachiasmatic, paraventricular, periventricular, supraoptic, dorsomedial and arcuate nuclei. Identical expression patterns for miR-7a was seen in mouse and rat hypothalamus. By combining LNA-FISH with immunohistochemistry...

  5. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    Science.gov (United States)

    Bond, Tiziana C.; Miles, Robin; Davidson, James C.; Liu, Gang Logan

    2014-07-22

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  6. 75 FR 49487 - Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray

    Science.gov (United States)

    2010-08-13

    ... AGENCY Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray AGENCY: Environmental Protection... period for the draft document ``Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray'' (EPA.... ] ADDRESSES: The draft ``Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray'' is available...

  7. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Tiziana C; Miles, Robin; Davidson, James; Liu, Gang Logan

    2015-11-03

    Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

  8. Nanoscale characterization of surfaces and interfaces

    CERN Document Server

    DiNardo, N John

    2008-01-01

    Derived from the highly acclaimed series Materials Science and Technology, this book provides in-depth coverage of STM, AFM, and related non-contact nanoscale probes along with detailed applications, such as the manipulation of atoms and clusters on a nanometer scale. The methods are described in terms of the physics and the technology of the methods and many high-quality images demonstrate the power of these techniques in the investigation of surfaces and the processes which occur on them.Topics include:Semiconductor Surfaces and Interfaces * Insulators * Layered Compounds * Charg

  9. Nonlinear Quantum Optics in Optomechanical Nanoscale Waveguides

    CERN Document Server

    Zoubi, Hashem

    2016-01-01

    We explore the possibility of achieving a significant nonlinear phase shift among photons propagating in nanoscale waveguides exploiting interactions among photons that are mediated by vibrational modes and induced through Stimulated Brillouin Scattering (SBS). We introduce a configuration that allows slowing down the photons by several orders of magnitude via SBS involving sound waves and two pump fields. We extract the conditions for maintaining vanishing amplitude gain or loss for slowly propagating photons while keeping the influence of thermal phonons to the minimum. The nonlinear phase among two counter-propagating photons can be used to realize a deterministic phase gate.

  10. Nanoscale atomic waveguides with suspended carbon nanotubes

    CERN Document Server

    Peano, V; Kasper, A; Egger, R

    2005-01-01

    We propose an experimentally viable setup for the realization of one-dimensional ultracold atom gases in a nanoscale magnetic waveguide formed by single doubly-clamped suspended carbon nanotubes. We show that all common decoherence and atom loss mechanisms are small guaranteeing a stable operation of the trap. Since the extremely large current densities in carbon nanotubes are spatially homogeneous, our proposed architecture allows to overcome the problem of fragmentation of the atom cloud. Adding a second nanowire allows to create a double-well potential with a moderate tunneling barrier which is desired for tunneling and interference experiments with the advantage of tunneling distances being in the nanometer regime.

  11. Attosecond nanoscale near-field sampling

    CERN Document Server

    Förg, Benjamin; Suessmann, Frederik; Foerster, Michael; Krueger, Michael; Ahn, Byung-Nam; Wintersperger, Karen; Zherebtsov, Sergey; Guggenmos, Alexander; Pervak, Vladimir; Kessel, Alexander; Trushin, Sergei; Azzeer, Abdallah; Stockman, Mark; Kim, Dong-Eon; Krausz, Ferenc; Hommelhoff, Peter; Kling, Matthias

    2015-01-01

    The promise of ultrafast light field driven electronic nanocircuits has stimulated the development of the new research field of attosecond nanophysics. An essential prerequisite for advancing this new area is the ability to characterize optical nearfields from light interaction with nanostructures with sub cycle resolution. Here, we experimentally demonstrate attosecond nearfield retrieval with a gold nanotip using streaking spectroscopy. By comparison of the results from gold nanotips to those obtained for a noble gas, the spectral response of the nanotip near field arising from laser excitation can be extracted. Monte Carlo MC trajectory simulations in near fields obtained with the macroscopic Maxwells equations elucidate the streaking mechanism on the nanoscale.

  12. Nanoscale Morphology Control in Functional Polymer Systems

    Institute of Scientific and Technical Information of China (English)

    Joachim; Loos; Svetlana; Chevtchenko

    2007-01-01

    1 Results In high-performance organic solar cells,the photoactive layer consists of a blend of an electron donor and an electron acceptor constituent,a so-called bulk heterojunction.The requirements to morphology of the efficient photoactive layer are nanoscale phase separation,which provides large interface area for exciton dissociation,and at the same time continuous pathways for transport of free charge carriers to the appropriate electrodes.In this context,the research is now focused on a better und...

  13. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji

    2011-04-21

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  14. Dynamic Behaviour of Nanoscale Electrostatic Actuators

    Institute of Scientific and Technical Information of China (English)

    林文惠; 赵亚溥

    2003-01-01

    The dynamic behaviour for nanoscale electrostatic actuators is studied.A two parameter mass-spring model is shown to exhibit a bifurcation from the case excluding an equilibrium point to the case including two equilibrium points as the geometrical dimensions of the device are altered.Stability analysis shows that one is a stable Hopf bifurcation point and the other is an unstable saddle point.In addition,we plot the diagram phases,which have periodic orbits around the Hopf point and a homoclinic orbit passing though the unstable saddle point.

  15. Nanoscale deicing by molecular dynamics simulation

    Science.gov (United States)

    Xiao, Senbo; He, Jianying; Zhang, Zhiliang

    2016-07-01

    Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion.Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice

  16. Coherent Light Sources at the Nanoscale

    Science.gov (United States)

    Yang, Ankun; Wang, Danqing; Wang, Weijia; Odom, Teri W.

    2017-05-01

    This review focuses on coherent light sources at the nanoscale, and specifically on lasers exploiting plasmonic cavities that can beat the diffraction limit of light. Conventional lasers exhibit coherent, intense, and directional emission with cavity sizes much larger than their operating wavelength. Plasmon lasers show ultrasmall mode confinement, support strong light-matter interactions, and represent a class of devices with extremely small sizes. We discuss the differences between plasmon lasers and traditional ones, and we highlight advances in directionality and tunability through innovative cavity designs and new materials. Challenges and future prospects are also discussed.

  17. Nanoscale investigation of organic - inorganic halide perovskites

    Science.gov (United States)

    Cacovich, S.; Divitini, G.; Vrućinić, M.; Sadhanala, A.; Friend, R. H.; Sirringhaus, H.; Deschler, F.; Ducati, C.

    2015-10-01

    Over the last few years organic - inorganic halide perovskite-based solar cells have exhibited a rapid evolution, reaching certified power conversion efficiencies now surpassing 20%. Nevertheless the understanding of the optical and electronic properties of such systems on the nanoscale is still an open problem. In this work we investigate two model perovskite systems (based on iodine - CH3NH3PbI3 and bromine - CH3NH3PbBr3), analysing the local elemental composition and crystallinity and identifying chemical inhomogeneities.

  18. Micro- and nanoscale phenomena in tribology

    CERN Document Server

    Chung, Yip-Wah

    2011-01-01

    Drawn from presentations at a recent National Science Foundation Summer Institute on Nanomechanics, Nanomaterials, and Micro/Nanomanufacturing, Micro- and Nanoscale Phenomena in Tribology explores the convergence of the multiple science and engineering disciplines involved in tribology and the connection from the macro to nano world. Written by specialists from computation, materials science, mechanical engineering, surface physics, and chemistry, each chapter provides up-to-date coverage of both basic and advanced topics and includes extensive references for further study.After discussing the

  19. Nanoscale growth twins in sputtered metal films

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Amit [Los Alamos National Laboratory; Anderoglu, Osman [Los Alamos National Laboratory; Hoagland, Richard G [Los Alamos National Laboratory; Zhang, X [TEXAS A& M

    2008-01-01

    We review recent studies on the mechanical properties of sputtered Cu and 330 stainless steel films with {l_brace}1 1 1{r_brace} nanoscale growth twins preferentially oriented perpendicular to growth direction. The mechanisms of formation of growth twins during sputtering and the deformation mechanisms that enable usually high strengths in nanotwinned structures are highlighted. Growth twins in sputtered films possess good thermal stability at elevated temperature, providing an approach to extend the application of high strength nanostructured metals to higher temperatures.

  20. Energy Management Strategies for a Pneumatic-Hybrid Engine Based on Sliding Window Pattern Recognition Stratégies de gestion de l’énergie pour un moteur hybride pneumatique basées sur la reconnaissance du cycle de conduite

    Directory of Open Access Journals (Sweden)

    Ivanco A.

    2009-11-01

    Full Text Available This paper presents energy management strategies for a new hybrid pneumatic engine concept which is specific by its configuration in that it is not the vehicle but only the engine itself which is hybridized. Different energy management strategies are proposed in this paper. The first is called Causal Strategy (CS and implements a rule-based control technique. The second strategy, called Constant Penalty Coefficient (CPC, is based on the minimization of equivalent consumption, where the use of each energy source is formulated in a comparative unit. The balance between the consumption of different energy sources (chemical or pneumatic is achieved by the introduction of an equivalence factor. The third strategy is called Variable Penalty Coefficient (VPC. In fact, it is beneficial to consider the equivalence coefficient as variable within the amount of pneumatic energy stored in the air-tank i.e. state of charge, because the choice of propulsion mode should be different if the tank is full or empty. In this case, the penalty coefficient appears as a non linear function of the air-tank state of charge. Another way to adapt the penalty coefficient is to recognize a reference pattern during the driving cycle. The coefficient value can then be changed according to an optimized value found for each of the reference cycles. This strategy is called Driving Pattern Recognition (DPR. It involves a technique of sliding window pattern recognition. The concept is to convert the whole driving cycle into smaller pieces to which the equivalence factor can be appropriately adapted. This strategy is based on the assumption that the current driving situation does not change rapidly and thus the pattern is likely to continue into the near future. The identification window size is a parameter which has to be adjusted to attain the maximum of identification success over the reference cycle. We propose to define reference patterns as statistical models. The pattern

  1. Temperature-dependent morphology of hybrid nanoflowers from elastin-like polypeptides

    Directory of Open Access Journals (Sweden)

    Koushik Ghosh

    2014-02-01

    Full Text Available We report a method for creating hybrid organic-inorganic “nanoflowers” using calcium or copper ions as the inorganic component and a recombinantly expressed elastin-like polypeptide (ELP as the organic component. Polypeptides provide binding sites for the dynamic coordination with metal ions, and then such noncovalent complexes become nucleation sites for primary crystals of metal phosphates. We have shown that the interaction between the stimuli-responsive ELP and Ca2+ or Cu2+, in the presence of phosphate, leads to the growth of micrometer-sized particles featuring nanoscale patterns shaped like flower petals. The morphology of these flower-like composite structures is dependent upon the temperature of growth and has been characterized by scanning electron microscopy. The composition of nanoflowers has also been analyzed by energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The temperature-dependent morphologies of these hybrid nanostructures, which arise from the controllable phase transition of ELPs, hold potential for morphological control of biomaterials in emerging applications such as tissue engineering and biocatalysis.

  2. Nanoscale optical imaging of semiconductor nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Boehmler, Miriam; Hartschuh, Achim [Department Chemie, CeNS, Ludwig-Maximilians-Universitaet Muenchen (Germany); Myalitsin, Anton; Mews, Alf [Department Chemie, Universitaet Hamburg (Germany)

    2011-07-01

    Inorganic semiconducting nanowires (NWs) feature size-related optical properties which make them interesting for a wide range of applications, e.g. nanoscale optoelectronics, sensors, and photovoltaics. Their relevant length scales that are determined by nanowire diameter and exciton Bohr radius, however, can not be resolved by conventional diffraction limited methods. We illustrate the prospects of tip-enhanced near-field optical microscopy (TENOM) as a method to investigate single nanowires. In TENOM a sharp metallic tip acts as optical antenna thereby enhancing the detected signal and increasing the optical resolution to about 15 nm. We present our investigations of CdSe NWs which have been grown by the wet chemical solution liquid solid technique. Here, TENOM provides the possibility to simultaneously image photoluminescence (PL) as well as Raman scattering of individual NWs with nanoscale resolution. We observe spatial variations of the PL intensity and energy on a length scale of about 15 nm indicating crystal phase transitions and diameter fluctuations.

  3. Nanoscale deicing by molecular dynamics simulation.

    Science.gov (United States)

    Xiao, Senbo; He, Jianying; Zhang, Zhiliang

    2016-08-14

    Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion.

  4. Svnthesis and Characterization of Nanoscale Mullite Powder

    Institute of Scientific and Technical Information of China (English)

    ZHAO Huizhong; HU Shoutian; WANG Houzhi; ZHANG Wenjie

    2003-01-01

    Nanoscale mullite powder were synthesized via Solgel-SCFD and middle temperature treatment by using AIP( aluminum-isopropoxde ) and TEOS ( tetraethyl orthosdicate) as starting materials. Both of the binary aerogel of alumina-silica and calcined nanoscale materials were investigated by using TG-DSC (thermogravimetry-differential scanning calorimeter), TEM (transmission electron microscope), XRD ( X-Ray diffractometer ) and specific surface area and porosimetry. TG-DSC indicated the removal of most of the volatiles , i. e. 15.98% up to about 700℃ ,and in the DSC curve, existence of two exothermic peak at about 445℃ and 1015℃ may be due to the crystallization of Si-O-Al-O in diphasic gels and mullitization and a small endothermic peak at about 805℃ indicated the decomposition of structural water molecules. On the colligation of the results of TG- DSC, XRD and TEM , the beginning temperature of mullitization in Al2 O3-SiO2 aerogel system can be confirmed at about 1015℃. XRD results also showed the formation of mullite at the range 1100 ~1200℃. TEM and surface area and porosimetry results showed that the nanosized mullite were calcinated at 1100and 1200℃ exhibited size 30nm and 50nm, specific surface area 138.91m2/g and 95.81m2/g.

  5. Nanomaterial Case Studies: Nanoscale Titanium Dioxide in ...

    Science.gov (United States)

    EPA announced the availability of the final report, Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen. This report is a starting point to determine what is known and what needs to be known about selected nanomaterials as part of a process to identify and prioritize research to inform future assessments of the potential ecological and health implications of these materials. Two specific applications of nanoscale titanium dioxide (nano-TiO2) are considered: (1) as an agent for removing arsenic from drinking water; and (2) as an active ingredient in topical sunscreen. These case studies are organized around a comprehensive environmental assessment (CEA) framework that combines a product life cycle perspective with the risk assessment paradigm. They are intended to help identify what may need to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. These “case studies” do not represent completed or even preliminary assessments, nor are they intended to serve as a basis for risk management decisions in the near term on these specific uses of nano TiO2. Rather, the intent is to use this document in developing the scientific and technical information needed for future assessment efforts.

  6. Transport and structure in nanoscale channels

    Science.gov (United States)

    Lakatos, Gregory William

    Driven by the rapidly advancing fields of nano- and biotechnology, there has been an explosion of interest in molecular transport and structure formation on small length scales. A canonical model for the transport of particles along one dimensional pathways in nanoscale channels is the Totally Asymmetric Simple Exclusion Process (TASEP). After introducing the standard TASEP, modifications of the TASEP designed to increase its utility in modeling biological transport processes are described. One variant of the TASEP is particularly suitable for modeling protein translation, and the results of using this variant to investigate the effects of slow-codons on the translation process are discussed. A related topic is the voltage-driven translocation of DNA hairpins through membrane-embedded nanopores. Motivated by recent experiments, a stochastic model is developed that couples the translocation and dehybridization of the DNA hairpin. This model is used to explore the behaviour of the mean translocation time of hairpins as a function of driving voltage, and two translocation mechanisms are identified and discussed. Finally, the adsorption and equilibrium structures of water in the interior of ion-bearing nanoscale pores are considered. The behaviour of water and ions under confinement is critical to the functioning of biological ion channels and nanoporous filters. Here, the adsorption isotherms of water are examined, and the layered structures formed by the confined water are described.

  7. Nanoscale Morphology of Sulfonated Polystyrene Ionomers

    Science.gov (United States)

    Zhou, Nancy C.; Winey, Karen I.

    2007-03-01

    We have applied our scanning transmission electron microscopy (STEM) methods to investigate the size, shape and spatial distribution of the ionic, nanoscale aggregates in poly(styrene-ran-styrene sulfonate) (P(S-SSx)) ionomers. This analytical electron microscopy method minimizes phase contrast that can obscure nano-scale features and accentuates differences in atomic number. We recently reported quantitative agreement between STEM and X-ray scattering results in a Cu-neutralized poly(styrene-ran-methacrylic acid) (SMAA) ionomer with respect to the size of the ionic aggregates and their number density. For this study, P(S-SSx) ionomers were prepared by solution neutralizing with metal acetates, solution casting, and annealing. Initial STEM results from P(S-SS0.019) fully neutralized with Zn indicate a uniform distribution of monodisperse spherical aggregates. Combining direct imaging and X-ray scattering of P(S-SSx) ionomers, we will investigate the effect of cation type and level of neutralization.

  8. Structure of nanoscale gas bubbles in metals

    Energy Technology Data Exchange (ETDEWEB)

    Caro, A., E-mail: caro@lanl.gov; Schwen, D.; Martinez, E. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2013-11-18

    A usual way to estimate the amount of gas in a bubble inside a metal is to assume thermodynamic equilibrium, i.e., the gas pressure P equals the capillarity force 2γ/R, with γ the surface energy of the host material and R the bubble radius; under this condition there is no driving force for vacancies to be emitted or absorbed by the bubble. In contrast to the common assumption that pressure inside a gas or fluid bubble is constant, we show that at the nanoscale this picture is no longer valid. P and density can no longer be defined as global quantities determined by an equation of state (EOS), but they become functions of position because the bubble develops a core-shell structure. We focus on He in Fe and solve the problem using both continuum mechanics and empirical potentials to find a quantitative measure of this effect. We point to the need of redefining an EOS for nanoscale gas bubbles in metals, which can be obtained via an average pressure inside the bubble. The resulting EOS, which is now size dependent, gives pressures that differ by a factor of two or more from the original EOS for bubble diameters of 1 nm and below.

  9. Quantifying Nanoscale Order in Amorphous Materials via Fluctuation Electron Microscopy

    Science.gov (United States)

    Bogle, Stephanie Nicole

    2009-01-01

    Fluctuation electron microscopy (FEM) has been used to study the nanoscale order in various amorphous materials. The method is explicitly sensitive to 3- and 4-body atomic correlation functions in amorphous materials; this is sufficient to establish the existence of structural order on the nanoscale, even when the radial distribution function…

  10. Method to determine thermal profiles of nanoscale circuitry

    Science.gov (United States)

    Zettl, Alexander K; Begtrup, Gavi E

    2013-04-30

    A platform that can measure the thermal profiles of devices with nanoscale resolution has been developed. The system measures the local temperature by using an array of nanoscale thermometers. This process can be observed in real time using a high resolution imagining technique such as electron microscopy. The platform can operate at extremely high temperatures.

  11. Bumpy, Sticky, and Shaky: Nanoscale Science and the Curriculum

    Science.gov (United States)

    Taylor, Amy; Jones, Gail; Pearl, Thomas P.

    2008-01-01

    Nanoscience, or the study of the world at the size of a billionth of a meter, has the potential to help students see how all of the sciences are related. Behavior of materials at the nanoscale differs from materials at the macroscale. This article introduces three nanoscale properties and how they relate to various science domains. Three…

  12. Frontier in nanoscale flows fractional calculus and analytical methods

    CERN Document Server

    Lewis, Roland; Liu, Hong-yan

    2014-01-01

    This ebook covers the basic properties of nanoscale flows, and various analytical and numerical methods for nanoscale flows and environmental flows. This ebook is a good reference not only for audience of the journal, but also for various communities in mathematics, nanotechnology and environmental science.

  13. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  14. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  15. Quantifying Nanoscale Order in Amorphous Materials via Fluctuation Electron Microscopy

    Science.gov (United States)

    Bogle, Stephanie Nicole

    2009-01-01

    Fluctuation electron microscopy (FEM) has been used to study the nanoscale order in various amorphous materials. The method is explicitly sensitive to 3- and 4-body atomic correlation functions in amorphous materials; this is sufficient to establish the existence of structural order on the nanoscale, even when the radial distribution function…

  16. Probing light emission at the nanoscale with cathodoluminescence

    NARCIS (Netherlands)

    B.J.M. Brenny

    2016-01-01

    Nanophotonics, the study of light at the nanoscale, is a vibrant field of research with a wide variety of applications. To mold and control light at the nanoscale, it is essential to measure and characterize nanostructures and their interaction with light at this subwavelength scale. This thesis des

  17. HYBRID GREY WOLF OPTIMIZATION-PATTERN SEARCH (hGWO-PS OPTIMIZED 2DOF-PID CONTROLLERS FOR LOAD FREQUENCY CONTROL (LFC IN INTERCONNECTED THERMAL POWER PLANTS

    Directory of Open Access Journals (Sweden)

    V Soni

    2016-04-01

    Full Text Available The combination of Grey Wolf Optimization and Pattern Search Technique (hGWO-PS has been introduced to optimize the parameters of two Degree of Freedom Proportional-Integral-Derivative Controller (2DOF-PID for controlling the load frequency in Automatic Generation Control (AGC for interconnected power system. The interconnected two area power system of non-reheat thermal power plants consisting of 2DOF-PID controller in each area has been considered for design and analysis. Firstly, the proposed approach has been implemented in the aforementioned standard test system and thereafter, the robustness of the system consisting 2DOF-PID controller optimized by proposed technique has been estimated using the sensitivity analysis for the same. The robustness of the system consisting of 2DOF-PID controller optimized by proposed scheme is examined by varying the parameters of standard test system, loading conditions during operation, size and location of the disturbances. The performance of the 2DOF-PID controller optimized by proposed approach has also been compared with recently published approaches in the literature. The simulation results show that the proposed hGWOPS optimized 2DOF-PID controller shows far better performance than recently published approaches in the literature in terms of dynamic response. The simulation results also show that system performances hardly change when the operating load condition and system parameters are changed by ±50% from their nominal values, i.e. the proposed controllers are quite robust for a wide range of the system parameters and operating load conditions from their nominal values.

  18. The growth and applications of silicides for nanoscale devices.

    Science.gov (United States)

    Lin, Yung-Chen; Chen, Yu; Huang, Yu

    2012-03-01

    Metal silicides have been used in silicon technology as contacts to achieve high device performance and desired device functions. The growth and applications of silicide materials have recently attracted increasing interest for nanoscale device applications. Nanoscale silicide materials have been demonstrated with various synthetic approaches. Solid state reaction wherein high quality silicides form through diffusion of metal atoms into silicon nano-templates and the subsequent phase transformation caught significant attention for the fabrication of nanoscale Si devices. Very interestingly, studies on the diffusion and phase transformation processes at the nanoscale have indicated possible deviations from the bulk and the thin film system. Here we present a review of fabrication, growth kinetics, electronic properties and device applications of nanoscale silicides formed through solid state reaction.

  19. The hybrid BCI

    Directory of Open Access Journals (Sweden)

    Gert Pfurtscheller

    2010-04-01

    Full Text Available Nowadays, everybody knows what a hybrid car is. A hybrid car normally has 2 engines, its main purpose being to enhance energy efficiency and reduce CO2 output. Similarly, a typical hybrid brain-computer interface (BCI is also composed of 2 BCIs or at least one BCI and another system. Such a hybrid BCI, like any BCI, must fulfil the following four criteria: (i the device must rely on signals recorded directly from the brain; (ii there must be at least one recordable brain signal that the user can intentionally modulate to effect goal-directed behaviour; (iii real time processing; and (iv the user must obtain feedback. This paper introduces some hybrid BCIs which have already been published or are currently in development or validation, and some concepts for future work. The BCIs described classify 2 EEG patterns: One is the event-related (desynchronisation (ERD, ERS of sensorimotor rhythms, and the other is the steady-state visual evoked potential (SSVEP. The hybrid BCI can either have more than one input whereby the inputs are typically processed simultaneously or operate 2 systems sequentially, whereby the first system can act as a “brain switch”. In the case of self-paced operation of a SSVEP-based hand orthosis control with an motor imagery-based switch it was possible to reduce the rate of false positives during resting periods by about 50% compared to the SSVEP BCI alone. It is shown that such a brain switch can also rely on hemodynamic changes measured through near-infrared spectroscopy (NIRS. Another interesting approach is a hybrid BCI with simultaneous operations of ERD- and SSVEP-based BCIs. Here it is important to prove the existing promising offline simulation results with online experiments. Hybrid BCIs can also use one brain signal and another input. Such an additional input can be a physiological signal like the heart rate but also a signal from an external device like, an eye gaze control system.

  20. Metal-dielectric hybrid surfaces as integrated optoelectronic interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, Vijay K.; Hymel, Thomas M.; Lai, Ruby A.; Cui, Yi

    2017-01-03

    An optoelectronic device has a hybrid metal-dielectric optoelectronic interface including an array of nanoscale dielectric resonant elements (e.g., nanopillars), and a metal film disposed between the dielectric resonant elements and below a top surface of the resonant elements such that the dielectric resonant elements protrude through the metal film. The device may also include an anti-reflection coating. The device may further include a metal film layer on each of the dielectric resonant elements.

  1. Micro/nanoscale electrohydrodynamic printing: from 2D to 3D.

    Science.gov (United States)

    Zhang, Bing; He, Jiankang; Li, Xiao; Xu, Fangyuan; Li, Dichen

    2016-08-25

    Electrohydrodynamic printing (EHDP), based on the electrohydrodynamically induced flow of materials, enables the production of micro/nanoscale fibers or droplets and has recently attracted extensive interest to fabricate user-specific patterns in a controlled and high-efficiency manner. However, most of the existing EHDP techniques can only print two-dimensional (2D) micropatterns which cannot meet the increasing demands for the direct fabrication of three-dimensional (3D) microdevices. The integration of EHDP techniques with the layer-by-layer stacking principle of additive manufacturing has emerged as a promising solution to this limitation. Here we present a state-of-the-art review on the translation of 2D EHDP technique into a viable micro/nanoscale 3D printing strategy. The working principle, essential components as well as critical process parameters for EHDP are discussed. We highlight recent explorations on both solution-based and melt-based 3D EHDP techniques in cone-jet and microdripping modes for the fabrication of multimaterial structures, microelectronics and biological constructs. Finally, we discuss the major challenges as well as possible solutions with regard to translating the 3D EHDP process into a real micro/nanoscale additive manufacturing strategy for the freeform fabrication of 3D structures.

  2. A Dual-Stage Hydrothermal Flow Reactor for Green and Sustainable Synthesis of Advanced Hybrid Nanomaterials

    DEFF Research Database (Denmark)

    Hellstern, Henrik Christian Lund

    2016-01-01

    Nanocomposites are a group of materials of growing scientific interest. The combination of two different materials into a single hybrid particle on the nanoscale can result in multifunctional materials or be used to enhance existing properties through synergistic interactions. Such novel material...

  3. Characterization of the nanoscale structure of milk fat.

    Science.gov (United States)

    Ramel, Pere Randy R; Peyronel, Fernanda; Marangoni, Alejandro G

    2016-07-15

    The nanoscale structure of milk fat (MF) crystal networks is extensively described for the first time through the characterization of milk fat-crystalline nanoplatelets (MF-CNPs). Removing oil by washing with cold isobutanol and breaking-down crystal aggregates by controlled homogenization allowed for the extraction and visualization of individual MF-CNPs that are mainly composed of high melting triacylglycerols (TAGs). By image analysis, the length and width of MF-CNPs were measured (600 nm × 200 nm-900 nm × 300 nm). Using small-angle X-ray scattering (SAXS), crystalline domain size, (i.e., thickness of MF-CNPs), was determined (27 nm (d001)). Through interpretation of ultra-small-angle X-ray scattering (USAXS) patterns of MF using Unified Fit and Guinier-Porod models, structural properties of MF-CNPs (smooth surfaces) and MF-CNP aggregations were characterized (RLCA aggregation of MF-CNPs to form larger structures that present diffused surfaces). Elucidation of MF-CNPs provides a new dimension of analysis for describing MF crystal networks and opens-up opportunities for modifying MF properties through nanoengineering.

  4. Nanoscale deformation measurements for reliability assessment of material interfaces

    Science.gov (United States)

    Keller, Jürgen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

    2006-03-01

    With the development and application of micro/nano electronic mechanical systems (MEMS, NEMS) for a variety of market segments new reliability issues will arise. The understanding of material interfaces is the key for a successful design for reliability of MEMS/NEMS and sensor systems. Furthermore in the field of BIOMEMS newly developed advanced materials and well known engineering materials are combined despite of fully developed reliability concepts for such devices and components. In addition the increasing interface-to volume ratio in highly integrated systems and nanoparticle filled materials are challenges for experimental reliability evaluation. New strategies for reliability assessment on the submicron scale are essential to fulfil the needs of future devices. In this paper a nanoscale resolution experimental method for the measurement of thermo-mechanical deformation at material interfaces is introduced. The determination of displacement fields is based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object (i.e. material interface) are carried out at different thermo-mechanical load states. The obtained images are compared by grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results are full-field displacement fields with nanometer resolution. With the obtained data the mixed mode type of loading at material interfaces can be analyzed with highest resolution for future needs in micro system and nanotechnology.

  5. Ordered nanoscale domains by infiltration of block copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Darling, Seth B.; Elam, Jeffrey; Tseng, Yu-Chih; Peng, Qing

    2016-11-08

    A method of preparing tunable inorganic patterned nanofeatures by infiltration of a block copolymer scaffold having a plurality of self-assembled periodic polymer microdomains. The method may be used sequential infiltration synthesis (SIS), related to atomic layer deposition (ALD). The method includes selecting a metal precursor that is configured to selectively react with the copolymer unit defining the microdomain but is substantially non-reactive with another polymer unit of the copolymer. A tunable inorganic features is selectively formed on the microdomain to form a hybrid organic/inorganic composite material of the metal precursor and a co-reactant. The organic component may be optionally removed to obtain an inorganic features with patterned nanostructures defined by the configuration of the microdomain.

  6. Highly stretchable piezoelectric-pyroelectric hybrid nanogenerator.

    Science.gov (United States)

    Lee, Ju-Hyuck; Lee, Keun Young; Gupta, Manoj Kumar; Kim, Tae Yun; Lee, Dae-Yeong; Oh, Junho; Ryu, Changkook; Yoo, Won Jong; Kang, Chong-Yun; Yoon, Seok-Jin; Yoo, Ji-Beom; Kim, Sang-Woo

    2014-02-01

    A highly stretchable hybrid nanogenerator has been developed using a micro-patterned piezoelectric polymer P(VDF-TrFE), PDMS-CNT composite, and graphene nanosheets. Mechanical and thermal energies are simultaneously harvested from a single cell of the device. The hybrid nanogenerator exhibits high robustness behavior even after 30% stretching and generates very stable piezoelectric and pyroelectric power outputs due to micro-pattern designing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Optical bistability in artificial composite nanoscale molecules: Towards all optical processing at the nanoscale

    CERN Document Server

    Malyshev, A V

    2010-01-01

    Optical response of artificial composite nanoscale molecules comprising a closely spaced noble metal nanoparticle and a semiconductor quantum dot have been studied theoretically. We consider a system composed of an Au particle and CdSe or CdSe/ZnSe quantum dot and predict optical bistability and hysteresis in its response, which suggests various applications, in particular, all-optical processing and optical memory.

  8. Wireless communication system via nanoscale plasmonic antennas.

    Science.gov (United States)

    Merlo, Juan M; Nesbitt, Nathan T; Calm, Yitzi M; Rose, Aaron H; D'Imperio, Luke; Yang, Chaobin; Naughton, Jeffrey R; Burns, Michael J; Kempa, Krzysztof; Naughton, Michael J

    2016-08-24

    Present on-chip optical communication technology uses near-infrared light, but visible wavelengths would allow system miniaturization and higher energy confinement. Towards this end, we report a nanoscale wireless communication system that operates at visible wavelengths via in-plane information transmission. Here, plasmonic antenna radiation mediates a three-step conversion process (surface plasmon → photon → surface plasmon) with in-plane efficiency (plasmon → plasmon) of 38% for antenna separation 4λ0 (with λ0 the free-space excitation wavelength). Information transmission is demonstrated at bandwidths in the Hz and MHz ranges. This work opens the possibility of optical conveyance of information using plasmonic antennas for on-chip communication technology.

  9. Focused electrojetting for nanoscale 3-D fabrication

    Science.gov (United States)

    Lee, Minhee; Kim, Ho-Young

    2012-11-01

    Although extreme miniaturization of components in integrated circuits and biochemical chips has driven the development of various nanofabrication technologies, three-dimensional fabrication of nanoscale objects is still in its infancy. Here we propose a novel method to fabricate a free-standing nanowall by the line-by-line deposition of electrospun polymer nanofibers. We show that the electrified nanojet, which tends to get unstable as traveling in free space due to the Coulombic repulsion, can be stably focused onto a narrow line of metal electrode. On the conducting line, the polymer nanojet is spontaneously folded successively to form a wall-like structure. We rationalize the period of spontaneous folding by balancing the tension in the polymer fiber with the electrostatic interaction of the fiber with the metal ground. This novel fabrication scheme can be applied for the development of three-dimensional bioscaffolds, nanofilters and nanorobots.

  10. Control of friction at the nanoscale

    Science.gov (United States)

    Barhen, Jacob; Braiman, Yehuda Y.; Protopopescu, Vladimir

    2010-04-06

    Methods and apparatus are described for control of friction at the nanoscale. A method of controlling frictional dynamics of a plurality of particles using non-Lipschitzian control includes determining an attribute of the plurality of particles; calculating an attribute deviation by subtracting the attribute of the plurality of particles from a target attribute; calculating a non-Lipschitzian feedback control term by raising the attribute deviation to a fractionary power .xi.=(2m+1)/(2n+1) where n=1, 2, 3 . . . and m=0, 1, 2, 3 . . . , with m strictly less than n and then multiplying by a control amplitude; and imposing the non-Lipschitzian feedback control term globally on each of the plurality of particles; imposing causes a subsequent magnitude of the attribute deviation to be reduced.

  11. Nanoscale decomposition of Nb-Ru-O

    Science.gov (United States)

    Music, Denis; Geyer, Richard W.; Chen, Yen-Ting

    2016-11-01

    A correlative theoretical and experimental methodology has been employed to explore the decomposition of amorphous Nb-Ru-O at elevated temperatures. Density functional theory based molecular dynamics simulations reveal that amorphous Nb-Ru-O is structurally modified within 10 ps at 800 K giving rise to an increase in the planar metal - oxygen and metal - metal population and hence formation of large clusters, which signifies atomic segregation. The driving force for this atomic segregation process is 0.5 eV/atom. This is validated by diffraction experiments and transmission electron microscopy of sputter-synthesized Nb-Ru-O thin films. Room temperature samples are amorphous, while at 800 K nanoscale rutile RuO2 grains, self-organized in an amorphous Nb-O matrix, are observed, which is consistent with our theoretical predictions. This amorphous/crystalline interplay may be of importance for next generation of thermoelectric devices.

  12. Magnetic switching of nanoscale antidot lattices

    Science.gov (United States)

    Gräfe, Joachim; Lebecki, Kristof M; Skripnik, Maxim; Haering, Felix; Schütz, Gisela; Ziemann, Paul; Goering, Eberhard; Nowak, Ulrich

    2016-01-01

    Summary We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices. PMID:27335762

  13. Inelastic transport theory for nanoscale systems

    DEFF Research Database (Denmark)

    Frederiksen, Thomas

    2007-01-01

    This thesis describes theoretical and numerical investigations of inelastic scat- tering and energy dissipation in electron transport through nanoscale sys- tems. A computational scheme, based on a combination of density functional theory (DFT) and nonequilibrium Green’s functions (NEGF), has been...... the conductance. The methods have been applied to a number of specific systems, includ- ing monatomic gold chains, atomic point contacts, and metal-molecule-metal configurations. These studies have clarified the inelastic effects in the elec- tron transport and characterized the vibrational modes that couple...... to the current. For instance, the dominant scattering for gold chains could be traced back to the longitudinal “alternating bond-length” mode. Furthermore, the results have been compared critically with experimental measurements for the different systems, and provided a microscopic understanding for the im...

  14. Transmission of torque at the nanoscale

    Science.gov (United States)

    Williams, Ian; Oğuz, Erdal C.; Speck, Thomas; Bartlett, Paul; Löwen, Hartmut; Royall, C. Patrick

    2016-01-01

    In macroscopic mechanical devices, torque is transmitted through gearwheels and clutches. In the construction of devices at the nanoscale, torque and its transmission through soft materials will be a key component. However, this regime is dominated by thermal fluctuations leading to dissipation. Here we demonstrate the principle of torque transmission for a disc-like colloidal assembly exhibiting clutch-like behaviour, driven by 27 particles in optical traps. These are translated on a circular path to form a rotating boundary that transmits torque to additional particles confined to the interior. We investigate this transmission and find that it is determined by solid-like or fluid-like behaviour of the device and a stick-slip mechanism reminiscent of macroscopic gearwheels slipping. The transmission behaviour is predominantly governed by the rotation rate of the boundary and the density of the confined system. We determine the efficiency of our device and thus optimize conditions to maximize power output.

  15. Implementation of perception and action at nanoscale

    CERN Document Server

    Marlière, Sylvain; Marchi, Florence; Luciani, Annie; Chevrier, Joel

    2008-01-01

    Real time combination of nanosensors and nanoactuators with virtual reality environment and multisensorial interfaces enable us to efficiently act and perceive at nanoscale. Advanced manipulation of nanoobjects and new strategies for scientific education are the key motivations. We have no existing intuitive representation of the nanoworld ruled by laws foreign to our experience. A central challenge is then the construction of nanoworld simulacrum that we can start to visit and to explore. In this nanoworld simulacrum, object identifications will be based on probed entity physical and chemical intrinsic properties, on their interactions with sensors and on the final choices made in building a multisensorial interface so that these objects become coherent elements of the human sphere of action and perception. Here we describe a 1D virtual nanomanipulator, part of the Cit\\'e des Sciences EXPO NANO in Paris, that is the first realization based on this program.

  16. Nanoscale device physics science and engineering fundamentals

    CERN Document Server

    Tiwari, Sandip

    2017-01-01

    Nanoscale devices are distinguishable from the larger microscale devices in their specific dependence on physical phenomena and effects that are central to their operation. The size change manifests itself through changes in importance of the phenomena and effects that become dominant and the changes in scale of underlying energetics and response. Examples of these include classical effects such as single electron effects, quantum effects such as the states accessible as well as their properties; ensemble effects ranging from consequences of the laws of numbers to changes in properties arising from different magnitudes of the inter-actions, and others. These interactions, with the limits placed on size, make not just electronic, but also magnetic, optical and mechanical behavior interesting, important and useful. Connecting these properties to the behavior of devices is the focus of this textbook. Description of the book series: This collection of four textbooks in the Electroscience series span the undergrad...

  17. Improvement in nanoscale contact resistance of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Manjima; Chakraborty, Riya; Mandal, Ashok Kumar [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); Dey, Arjun [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); ISRO Satellite Centre, Thermal Systems Group, Bangalore (India); Mukhopadhyay, Anoop Kumar [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); Central Glass and Ceramic Research Institute, Kolkata 32 (India)

    2012-06-15

    In all contact-related applications such as the wear-resistant inserts, biomedical implants, high strain rate impact-resistant plates, etc., nanohardness, i.e. the intrinsic contact resistance at the nano scale, plays a major role. In spite of the wealth of literature, the studies on nanohardness of dense, coarse-grain alumina ceramics which represent many commercial varieties; have reasonably good hardness at the macro scale and characteristically exhibit R-curve behaviour, are far from significant. Here, to the best of our knowledge, we report for the first time the experimental observations of the increase in intrinsic contact resistance at the nano scale with the loading rate applied to a high-density ({proportional_to}95 % of theoretical) coarse-grain ({proportional_to}20 {mu}m) alumina ceramics. These observations were explained in terms of the initiation of nanoscale plasticity and maximum shear stress generated just underneath the nanoindenter. (orig.)

  18. Quantum Transport Simulations of Nanoscale Materials

    KAUST Repository

    Obodo, Tobechukwu Joshua

    2016-01-07

    Nanoscale materials have many potential advantages because of their quantum confinement, cost and producibility by low-temperature chemical methods. Advancement of theoretical methods as well as the availability of modern high-performance supercomputers allow us to control and exploit their microscopic properties at the atomic scale, hence making it possible to design novel nanoscale molecular devices with interesting features (e.g switches, rectifiers, negative differential conductance, and high magnetoresistance). In this thesis, state-of-the-art theoretical calculations have been performed for the quantum transport properties of nano-structured materials within the framework of Density Functional Theory (DFT) and the Nonequilibrium Green\\'s Function (NEGF) formalism. The switching behavior of a dithiolated phenylene-vinylene oligomer sandwiched between Au(111) electrodes is investigated. The molecule presents a configurational bistability, which can be exploited in constructing molecular memories, switches, and sensors. We find that protonation of the terminating thiol groups is at the origin of the change in conductance. H bonding at the thiol group weakens the S-Au bond, and thus lowers the conductance. Our results allow us to re-interpret the experimental data originally attributing the conductance reduction to H dissociation. Also examined is current-induced migration of atoms in nanoscale devices that plays an important role for device operation and breakdown. We studied the migration of adatoms and defects in graphene and carbon nanotubes under finite bias. We demonstrate that current-induced forces within DFT are non-conservative, which so far has only been shown for model systems, and can lower migration barrier heights. Further, we investigated the quantum transport behavior of an experimentally observed diblock molecule by varying the amounts of phenyl (donor) and pyrimidinyl (acceptor) rings under finite bias. We show that a tandem configuration of

  19. Wireless communication system via nanoscale plasmonic antennas

    Science.gov (United States)

    Merlo, Juan M.; Nesbitt, Nathan T.; Calm, Yitzi M.; Rose, Aaron H.; D'Imperio, Luke; Yang, Chaobin; Naughton, Jeffrey R.; Burns, Michael J.; Kempa, Krzysztof; Naughton, Michael J.

    2016-08-01

    Present on-chip optical communication technology uses near-infrared light, but visible wavelengths would allow system miniaturization and higher energy confinement. Towards this end, we report a nanoscale wireless communication system that operates at visible wavelengths via in-plane information transmission. Here, plasmonic antenna radiation mediates a three-step conversion process (surface plasmon → photon → surface plasmon) with in-plane efficiency (plasmon → plasmon) of 38% for antenna separation 4λ0 (with λ0 the free-space excitation wavelength). Information transmission is demonstrated at bandwidths in the Hz and MHz ranges. This work opens the possibility of optical conveyance of information using plasmonic antennas for on-chip communication technology.

  20. Magnetic switching of nanoscale antidot lattices

    Directory of Open Access Journals (Sweden)

    Ulf Wiedwald

    2016-05-01

    Full Text Available We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.

  1. Exploring Carbon Nanotubes for Nanoscale Devices

    Science.gov (United States)

    Han, Jie; Dai; Anantram; Jaffe; Saini, Subhash (Technical Monitor)

    1998-01-01

    Carbon nanotubes (CNTs) are shown to promise great opportunities in nanoelectronic devices and nanoelectromechanical systems (NEMS) because of their inherent nanoscale sizes, intrinsic electric conductivities, and seamless hexagonal network architectures. I present our collaborative work with Stanford on exploring CNTs for nanodevices in this talk. The electrical property measurements suggest that metallic tubes are quantum wires. Furthermore, two and three terminal CNT junctions have been observed experimentally. We have proposed and studied CNT-based molecular switches and logic devices for future digital electronics. We also have studied CNTs based NEMS inclusing gears, cantilevers, and scanning probe microscopy tips. We investigate both chemistry and physics based aspects of the CNT NEMS. Our results suggest that CNT have ideal stiffness, vibrational frequencies, Q-factors, geometry-dependent electric conductivities, and the highest chemical and mechanical stabilities for the NEMS. The use of CNT SPM tips for nanolithography is presented for demonstration of the advantages of the CNT NEMS.

  2. Surface Properties from Transconductance in Nanoscale Systems.

    Science.gov (United States)

    Lynall, David; Byrne, Kristopher; Shik, Alexander; Nair, Selvakumar V; Ruda, Harry E

    2016-10-12

    Because of the continued scaling of transistor dimensions and incorporation of nanostructured materials into modern electronic and optoelectronic devices, surfaces and interfaces have become a dominant factor dictating material properties and device performance. In this study, we investigate the temperature-dependent electronic transport properties of InAs nanowire field-effect transistors. A point where the nanowire conductance becomes independent of temperature is observed, known as the zero-temperature-coefficient. The distribution of surface states is determined by a spectral analysis of the conductance activation energy and used to develop a carrier transport model that explains the existence and gate voltage dependence of this point. We determine that the position of this point in gate voltage is directly related to the fixed oxide charge on the nanowire surface and demonstrate the utility of this method for studying surface passivations in nanoscale systems by characterizing (NH4)2Sx and H2 plasma surface treatments on InAs nanowires.

  3. Nanoscale Characterization with Laser Picosecond Acoustics

    Science.gov (United States)

    Wright, Oliver B.

    2007-11-01

    Nanophotonics—the manipulation of light with nanomaterials—is a booming subject, its success owing to the host of nanoscale fabrication techniques now at our disposal. However, for the characterization of such nanomaterials it is expedient to turn to other types of waves with a wavelength commensurate with the nanostructure in question. One such choice is acoustic waves of nanometre wavelength. The aim of this article is to provide an introduction to laser picosecond acoustics, a means by which gigahertz-terahertz ultrasonic waves can be generated and detected by ultrashort light pulses. This method can therefore be used to characterize materials with nanometre spatial resolution. In this article we review the theoretical background for opaque single-layer thin film isotropic samples with reference to key experiments. Solids including metals and semiconductors are discussed, although liquids and, conceivably, gases, are not excluded.

  4. System reduction for nanoscale IC design

    CERN Document Server

    2017-01-01

    This book describes the computational challenges posed by the progression toward nanoscale electronic devices and increasingly short design cycles in the microelectronics industry, and proposes methods of model reduction which facilitate circuit and device simulation for specific tasks in the design cycle. The goal is to develop and compare methods for system reduction in the design of high dimensional nanoelectronic ICs, and to test these methods in the practice of semiconductor development. Six chapters describe the challenges for numerical simulation of nanoelectronic circuits and suggest model reduction methods for constituting equations. These include linear and nonlinear differential equations tailored to circuit equations and drift diffusion equations for semiconductor devices. The performance of these methods is illustrated with numerical experiments using real-world data. Readers will benefit from an up-to-date overview of the latest model reduction methods in computational nanoelectronics.

  5. An RNAi Screen for Genes Involved in Nanoscale Protrusion Formation on Corneal Lens in Drosophila melanogaster.

    Science.gov (United States)

    Minami, Ryunosuke; Sato, Chiaki; Yamahama, Yumi; Kubo, Hideo; Hariyama, Takahiko; Kimura, Ken-Ichi

    2016-12-01

    The "moth-eye" structure, which is observed on the surface of corneal lens in several insects, supports anti-reflective and self-cleaning functions due to nanoscale protrusions known as corneal nipples. Although the morphology and function of the "moth-eye" structure, are relatively well studied, the mechanism of protrusion formation from cell-secreted substances is unknown. In Drosophila melanogaster, a compound eye consists of approximately 800 facets, the surface of which is formed by the corneal lens with nanoscale protrusions. In the present study, we sought to identify genes involved in "moth-eye" structure, formation in order to elucidate the developmental mechanism of the protrusions in Drosophila. We re-examined the aberrant patterns in classical glossy-eye mutants by scanning electron microscope and classified the aberrant patterns into groups. Next, we screened genes encoding putative structural cuticular proteins and genes involved in cuticular formation using eye specific RNAi silencing methods combined with the Gal4/UAS expression system. We identified 12 of 100 candidate genes, such as cuticular proteins family genes (Cuticular protein 23B and Cuticular protein 49Ah), cuticle secretion-related genes (Syntaxin 1A and Sec61 ββ subunit), ecdysone signaling and biosynthesis-related genes (Ecdysone receptor, Blimp-1, and shroud), and genes involved in cell polarity/cell architecture (Actin 5C, shotgun, armadillo, discs large1, and coracle). Although some of the genes we identified may affect corneal protrusion formation indirectly through general patterning defects in eye formation, these initial findings have encouraged us to more systematically explore the precise mechanisms underlying the formation of nanoscale protrusions in Drosophila.

  6. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    Science.gov (United States)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    The recent technological developments in the synthesis and characterization of high-quality nanostructures and developments in the theoretical techniques needed to model these materials, have motivated this focus section of Superconductor Science and Technology. Another motivation is the compelling evidence that all new superconducting materials, such as iron pnictides and chalcogenides, diborides (doped MgB2) and fullerides (alkali-doped C60 compounds), are heterostrucures at the atomic limit, such as the cuprates made of stacks of nanoscale superconducting layers intercalated by different atomic layers with nanoscale periodicity. Recently a great amount of interest has been shown in the role of lattice nano-architecture in controlling the fine details of Fermi surface topology. The experimental and theoretical study of superconductivity in the nanoscale started in the early 1960s, shortly after the discovery of the BCS theory. Thereafter there has been rapid progress both in experiments and the theoretical understanding of nanoscale superconductors. Experimentally, thin films, granular films, nanowires, nanotubes and single nanoparticles have all been explored. New quantum effects appear in the nanoscale related to multi-component condensates. Advances in the understanding of shape resonances or Fano resonances close to 2.5 Lifshitz transitions near a band edge in nanowires, 2D films and superlattices [1, 2] of these nanosized modules, provide the possibility of manipulating new quantum electronic states. Parity effects and shell effects in single, isolated nanoparticles have been reported by several groups. Theoretically, newer techniques based on solving Richardson's equation (an exact theory incorporating finite size effects to the BCS theory) numerically by path integral methods or solving the entire Bogoliubov-de Gennes equation in these limits have been attempted, which has improved our understanding of the mechanism of superconductivity in these confined

  7. Blood clotting reactions on nanoscale phospholipid bilayers.

    Science.gov (United States)

    Morrissey, James H; Pureza, Vincent; Davis-Harrison, Rebecca L; Sligar, Stephen G; Ohkubo, Y Zenmei; Tajkhorshid, Emad

    2008-01-01

    Blood clotting reactions, such as those catalyzed by the tissue factor:factor VIIa complex (TF:FVIIa), assemble on membrane surfaces containing anionic phospholipids such as phosphatidylserine (PS). In fact, membrane binding is critical for the function of most of the steps in the blood clotting cascade. In spite of this, our understanding of how the membrane contributes to catalysis, or even how these proteins interact with phospholipids, is incomplete. Making matters more complicated, membranes containing mixtures of PS and neutral phospholipids are known to spontaneously form PS-rich membrane microdomains in the presence of plasma concentrations of calcium ions, and it is likely that blood-clotting proteases such as TF:FVIIa partition into these PS-rich microdomains. Unfortunately, little is known about how membrane microdomain composition influences the activity of blood-clotting proteases, which is typically not under experimental control even in "simple" model membranes. Our laboratories have developed and applied new technologies for studying membrane proteins to gain insights into how blood-clotting protease-cofactor pairs assemble and function on membrane surfaces. This includes using a novel, nanoscale bilayer system (Nanodiscs) that permits assembling blood-clotting protease-cofactor pairs on stable bilayers containing from 65 to 250 phospholipid molecules per leaflet. We have used this system to investigate how local (nanometer-scale) changes in phospholipid bilayer composition modulate TF:FVIIa activity. We have also used detailed molecular-dynamics simulations of nanoscale bilayers to provide atomic-scale predictions of how the membrane-binding domain of factor VIIa interacts with PS in membranes.

  8. Thermal stability of nanoscale metallic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, A.S., E-mail: sofia.ramos@dem.uc.pt [CEMUC, Departamento de Engenharia Mecânica, Universidade de Coimbra, 3030-788 Coimbra (Portugal); Cavaleiro, A.J.; Vieira, M.T. [CEMUC, Departamento de Engenharia Mecânica, Universidade de Coimbra, 3030-788 Coimbra (Portugal); Morgiel, J. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Reymonta 25, 30-059 Cracow (Poland); Safran, G. [Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, H-1121 Budapest (Hungary)

    2014-11-28

    Metallic nanolayered thin films/foils, in particular Ni/Al multilayers, have been used to promote joining. The objective of this work is to evaluate the thermal stability of nanoscale metallic multilayers with potential for joining applications. Multilayers thin films with low (Ti/Al and Ni/Ti), medium (Ni/Al) and high (Pd/Al) enthalpies of exothermic reaction were prepared by dual cathode magnetron sputtering. Their thermal stability was studied by: i) differential scanning calorimetry combined with X-ray diffraction (XRD), ii) in-situ XRD using cobalt radiation, and iii) in-situ transmission electron microscopy. It was possible to detect traces of intermetallic or amorphous phases in the as-deposited short period (bilayer thickness) multilayers, except for the Ti/Al films where no reaction products that might be formed during deposition were identified. For short periods (below 20 nm) the equilibrium phases are directly achieved upon annealing, whereas for higher periods intermediate trialuminide phases are present for Ti/Al and Ni/Al multilayers. The formation of B2-NiTi from Ni/Ti multilayers occurs without the formation of intermediate phases. On the contrary, for the Pd–Al system the formation of intermediate phases was never avoided. The viability of nanoscale multilayers as “filler” materials for joining macro or microparts/devices was demonstrated. - Highlights: • Me1 and Me2 (Me—metal) alternated nanolayers deposited by magnetron sputtering • Reactive Me1/Me2 multilayer thin films with nanometric modulation period • By heat treatment the films always evolve to the equilibrium intermetallic phase. • For some Me1–Me2 systems and periods, the formation of intermediate phases occurs. • Me1/Me2 multilayer thin films can be used as filler materials to enhance joining.

  9. Electrode-stress-induced nanoscale disorder in Si quantum electronic devices

    Science.gov (United States)

    Park, J.; Ahn, Y.; Tilka, J. A.; Sampson, K. C.; Savage, D. E.; Prance, J. R.; Simmons, C. B.; Lagally, M. G.; Coppersmith, S. N.; Eriksson, M. A.; Holt, M. V.; Evans, P. G.

    2016-06-01

    Disorder in the potential-energy landscape presents a major obstacle to the more rapid development of semiconductor quantum device technologies. We report a large-magnitude source of disorder, beyond commonly considered unintentional background doping or fixed charge in oxide layers: nanoscale strain fields induced by residual stresses in nanopatterned metal gates. Quantitative analysis of synchrotron coherent hard x-ray nanobeam diffraction patterns reveals gate-induced curvature and strains up to 0.03% in a buried Si quantum well within a Si/SiGe heterostructure. Electrode stress presents both challenges to the design of devices and opportunities associated with the lateral manipulation of electronic energy levels.

  10. Differential integrin expression regulates cell sensing of the matrix nanoscale geometry.

    Science.gov (United States)

    Di Cio, Stefania; Bøggild, Thea M L; Connelly, John; Sutherland, Duncan S; Gautrot, Julien E

    2017-03-01

    The nanoscale geometry and topography of the extra-cellular matrix (ECM) is an important parameter controlling cell adhesion and phenotype. Similarly, integrin expression and the geometrical maturation of adhesions they regulate have been correlated with important changes in cell spreading and phenotype. However, how integrin expression controls the nanoscale sensing of the ECM geometry is not clearly understood. Here we develop a new nanopatterning technique, electrospun nanofiber lithography (ENL), which allows the production of a quasi-2D fibrous nanopattern with controlled dimensions (250-1000nm) and densities. ENL relies on electrospun fibres to act as a mask for the controlled growth of protein-resistant polymer brushes. SEM, AFM and immunofluorescence imaging were used to characterise the resulting patterns and the adsorption of the extra-cellular matrix protein fibronectin to the patterned fibres. The control of adhesion formation was studied, as well as the remodelling and deposition of novel matrix. Cell spreading was found to be regulated by the size of fibres, similarly to previous observations made on circular nanopatterns. However, cell shape and polarity were more significantly affected. These changes correlated with important cytoskeleton reorganisation, with a gradual decrease in stress fibre formation as the pattern dimensions decrease. Finally, the differential expression of αvβ3 and α5β1 integrins in engineered cell lines was found to be an important mediator of cell sensing of the nanoscale geometry of the ECM. The novel nanofiber patterns developed in this study, via ENL, mimic the geometry and continuity of natural matrices found in the stroma of tissues, whilst preserving a quasi-2D character (to facilitate imaging and for comparison with other 2D systems such as micropatterned monolayers and circular nanopatches generated by colloidal lithography). These results demonstrate that the nanoscale geometry of the ECM plays an important role

  11. Shaping nanoscale magnetic domain memory in exchange-coupled ferromagnets by field cooling

    Science.gov (United States)

    Chesnel, Karine; Safsten, Alex; Rytting, Matthew; Fullerton, Eric E.

    2016-01-01

    The advance of magnetic nanotechnologies relies on detailed understanding of nanoscale magnetic mechanisms in materials. Magnetic domain memory (MDM), that is, the tendency for magnetic domains to repeat the same pattern during field cycling, is important for magnetic recording technologies. Here we demonstrate MDM in [Co/Pd]/IrMn films, using coherent X-ray scattering. Under illumination, the magnetic domains in [Co/Pd] produce a speckle pattern, a unique fingerprint of their nanoscale configuration. We measure MDM by cross-correlating speckle patterns throughout magnetization processes. When cooled below its blocking temperature, the film exhibits up to 100% MDM, induced by exchange-coupling with the underlying IrMn layer. The degree of MDM drastically depends on cooling conditions. If the film is cooled under moderate fields, MDM is high throughout the entire magnetization loop. If the film is cooled under nearly saturating field, MDM vanishes, except at nucleation and saturation. Our findings show how to fully control the occurrence of MDM by field cooling. PMID:27248368

  12. The Architectural Designs of a Nanoscale Computing Model

    Directory of Open Access Journals (Sweden)

    Mary M. Eshaghian-Wilner

    2004-08-01

    Full Text Available A generic nanoscale computing model is presented in this paper. The model consists of a collection of fully interconnected nanoscale computing modules, where each module is a cube of cells made out of quantum dots, spins, or molecules. The cells dynamically switch between two states by quantum interactions among their neighbors in all three dimensions. This paper includes a brief introduction to the field of nanotechnology from a computing point of view and presents a set of preliminary architectural designs for fabricating the nanoscale model studied.

  13. Nanoscale Morphology in Tensile Fracture of a Brittle Amorphous Ribbon

    Institute of Scientific and Technical Information of China (English)

    Xifeng LI; Kaifeng ZHANG; Guofeng WANG

    2008-01-01

    The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morphology on the fracture surfaces. Approaching the ribbon boundary, these damage cavities assemble and form the nanoscale periodic corrugations, which are neither Wallner lines nor crack front waves. The periodic corrugations result from the interactions between the reflected elastic waves by the boundaries of amorphous ribbon and the stress fields of the crack tip.

  14. Refractive index of nanoscale thickness films measured by Brewster refractometry

    CERN Document Server

    Tikhonov, E A; Malyukin, Yu V

    2015-01-01

    It is shown that reflective laser refractometery at Brewster angle can be usefull for precision measurements of refractive indexes (RI) in the transparency band of various films of nanoscale thickness. The RI measurements of nanoscale porous film on the basis of gadolinium orthosilicate and quartz have been carried out as first experience. It is shown that surface light scattering in such films that is connected with clustering of nanoscale pores can decrease the accuracy of the RI measurements at Brewster angle. Estimated physical dependence RI stipulated by the film thickness reduction (3D-2D transition) in the range of (20-160)nm has not been not detected.

  15. Continuous controllable amorphization ratio of nanoscale phase change memory cells

    Science.gov (United States)

    He, Q.; Li, Z.; Peng, J. H.; Deng, Y. F.; Zeng, B. J.; Zhou, W.; Miao, X. S.

    2014-06-01

    The controllable heat behavior, including heat generation and dissipation, is one of the most important physical problems of nanoscale phase-change memory (PCM). A method based on heat accumulation effect to control heat behavior by synthetically modulating the three parameters of applied double pulses is proposed to achieve any expected amorphization ratio. A compact model of nanoscale PCM cells is used to simulate the thermal behavior and amorphization ratio under the condition of single parameter and multi-parameter change of applied double pulses. The results are in good agreement with the experimental results. Repeated experiments also prove the feasibility of continuous controllable amorphization ratio of nanoscale phase-change materials.

  16. Asymmetric transportation induced by thermal noise at the nanoscale

    Institute of Scientific and Technical Information of China (English)

    WAN RongZheng; HU Jun; FANG HaiPing

    2012-01-01

    Based on a simple model,we theoretically show that asymmetric transportation is possible in nanoscale systems experiencing thermal noise without the presence of external fluctuations.The key to this theoretical advance is that the correlation lengths of the thermal fluctuations become significantly long for nanoscale systems.This differs from macroscopic systems in which the thermal noises are usually treated as white noise.Our observation does not violate the second law of thermodynamics,since at the nanoscale,extra energy is required to keep the asymmetric structure against thermal fluctuations.

  17. Charge transport in nanoscale vertical organic semiconductor pillar devices

    Science.gov (United States)

    Wilbers, Janine G. E.; Xu, Bojian; Bobbert, Peter A.; de Jong, Michel P.; van der Wiel, Wilfred G.

    2017-01-01

    We report charge transport measurements in nanoscale vertical pillar structures incorporating ultrathin layers of the organic semiconductor poly(3-hexylthiophene) (P3HT). P3HT layers with thickness down to 5 nm are gently top-contacted using wedging transfer, yielding highly reproducible, robust nanoscale junctions carrying high current densities (up to 106 A/m2). Current-voltage data modeling demonstrates excellent hole injection. This work opens up the pathway towards nanoscale, ultrashort-channel organic transistors for high-frequency and high-current-density operation.

  18. The Architectural Designs of a Nanoscale Computing Model

    Directory of Open Access Journals (Sweden)

    Mary M. Eshaghian-Wilner

    2004-08-01

    Full Text Available A generic nanoscale computing model is presented in this paper. The model consists of a collection of fully interconnected nanoscale computing modules, where each module is a cube of cells made out of quantum dots, spins, or molecules. The cells dynamically switch between two states by quantum interactions among their neighbors in all three dimensions. This paper includes a brief introduction to the field of nanotechnology from a computing point of view and presents a set of preliminary architectural designs for fabricating the nanoscale model studied.

  19. Nanoscale Mechanical Stimulation of Human Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    H Nikukar

    2014-05-01

    We observed significant responses after 1 and 2-week stimulations in cell number, cell shapes and phenotypical markers. Microarray was performed for all groups. Cell count showed normal cell growth with stimulation. However, cell surface area, cell perimeter, and arboration after 1-week stimulation showed significant increases. Immunofluorescent studies have showed significant increase in osteocalcin production after stimulation. Conclusions: Nanoscale mechanical vibration showed significant changes in human mesenchymal stem cell behaviours. Cell morphology changed to become more polygonal and increased expression of the osteoblast markers were noted. These findings with gene regulation changes suggesting nanoscale mechanostimulation has stimulated osteoblastogenesis.  Keywords:  Mesenchymal, Nanoscale, Stem Cells.

  20. Nanoscale Chemical and Electrical Stabilities of Graphene-covered Silver Nanowire Networks for Transparent Conducting Electrodes

    Science.gov (United States)

    Kim, Seong Heon; Choi, Woon Ih; Kim, Kwang Hee; Yang, Dae Jin; Heo, Sung; Yun, Dong-Jin

    2016-09-01

    The hybrid structure of Ag nanowires (AgNWs) covered with graphene (Gr) shows synergetic effects on the performance of transparent conducting electrodes (TCEs). However, these effects have been mainly observed via large-scale characterization, and precise analysis at the nanoscale level remains inadequate. Here, we present the nanoscale verification and visualization of the improved chemical and electrical stabilities of Gr-covered AgNW networks using conductive atomic force microscopy (C-AFM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) combined with the gas cluster ion beam (GCIB) sputtering technique. Specifically by transferring island Gr on top of the AgNW network, we were able to create samples in which both covered and uncovered AgNWs are simultaneously accessible to various surface-characterization techniques. Furthermore, our ab initio molecular dynamics (AIMD) simulation elucidated the specific mechanistic pathway and a strong propensity for AgNW sulfidation, even in the presence of ambient oxidant gases.

  1. Nanoscale guiding for cold atoms based on surface plasmons along the tips of metallic wedges

    Institute of Scientific and Technical Information of China (English)

    Wang Zheng-Ling; Tang Wei-Min; Zhou Ming; Gao Chuan-Yu

    2013-01-01

    We propose a novel scheme to guide neutral cold atoms in a nanoscale region based on surface plasmons (SPs) of one pair and two pairs of tips of metallic wedges with locally enhanced light intensity and sub-optical wavelength resolution.We analyze the near-field intensity distribution of the tip of the metallic wedge by the FDTD method,and study the total intensity as well as the total potential of optical potentials and van der Waals potentials for 87Rb atoms in the light field of one pair and two pairs of tips of metallic wedges.It shows that the total potentials of one pair and two pairs of tips of metallic wedges can generate a gravito-optical trap and a dark closed trap for nanoscale guiding of neutral cold atoms.Guided atoms can be cooled with efficient intensity-gradient Sisyphus cooling by blue-detuned light field.This provides an important step towards the generation of hybrid systems consisting of isolated atoms and solid devices.

  2. Nanoscale Chemical and Electrical Stabilities of Graphene-covered Silver Nanowire Networks for Transparent Conducting Electrodes.

    Science.gov (United States)

    Kim, Seong Heon; Choi, Woon Ih; Kim, Kwang Hee; Yang, Dae Jin; Heo, Sung; Yun, Dong-Jin

    2016-09-13

    The hybrid structure of Ag nanowires (AgNWs) covered with graphene (Gr) shows synergetic effects on the performance of transparent conducting electrodes (TCEs). However, these effects have been mainly observed via large-scale characterization, and precise analysis at the nanoscale level remains inadequate. Here, we present the nanoscale verification and visualization of the improved chemical and electrical stabilities of Gr-covered AgNW networks using conductive atomic force microscopy (C-AFM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS) combined with the gas cluster ion beam (GCIB) sputtering technique. Specifically by transferring island Gr on top of the AgNW network, we were able to create samples in which both covered and uncovered AgNWs are simultaneously accessible to various surface-characterization techniques. Furthermore, our ab initio molecular dynamics (AIMD) simulation elucidated the specific mechanistic pathway and a strong propensity for AgNW sulfidation, even in the presence of ambient oxidant gases.

  3. Exotic optoelectronic properties of organic semiconductors with super-controlled nanoscale sizes and molecular shapes.

    Science.gov (United States)

    Hotta, Shu; Yamao, Takeshi; Katagiri, Toshifumi

    2014-03-01

    We present several aspects of thiophene/phenylene co-oligomers (TPCOs). TPCOs are regarded as a newly occurring class of organic semiconductors. These materials are synthesized by hybridizing thiophene and phenylene rings at the molecular level with their various mutual arrangements. These materials are characterized by the super-controlled nanoscale sizes and molecular shapes. These produce peculiar crystallographic structures and high-performance optical and electronic properties. The crystals of TPCOs were obtained through both vapor phase and liquid phase. In the TPCO crystals, the molecules take upright configuration. These cause large carrier mobilities of field-effect transistors and laser oscillations under optical excitations. Spectrally-narrowed emissions (SNEs) were also achieved under weak optical excitation using a mercury lamp. The light-emitting field-effect transistors using these crystals for an active layer have shown the current-injected SNEs when the device was combined with an optical cavity and operated by an alternating-current gate-voltage method. Thus the TPCO materials will play an important role in the future in the fields of nanoscale technology and organic semiconductor materials as well as their optoelectronic device applications.

  4. NANOSTRUCTURE PATTERNING UNDER ENERGETIC PARTICLE BEAM IRRADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lumin [Regents of the University of Michigan; Lu, Wei [Regents of the University of Michigan

    2013-01-31

    understanding of fundamental scientific basis for the irradiation-induced self-organization processes. The fundamental physical mechanisms underlying ordered pattern formation, which include defect production and migration, ion sputtering, redeposition, viscous flow and diffusion, are investigated through a combination of modeling and in situ and ex-situ observations [3,9,11]. In addition, these nanostructured materials exhibit considerable improvement of optical properties [9,12,13]. For example, patterned Ge with a hexagonally ordered, honeycomb-like structure of nanoscale holes possesses a high surface area and a considerably blue-shifted energy gap [9], and oxidation of ordered Ga droplets shows noticeable enhancement of optical transmission [12]. This research has addressed nanopattern formation in a variety of materials under ion bombardment and provided a fundamental understanding of the dynamic mechanisms involved. In addition, have also stared to systematically investigate pattern formation under ion irradiation for more systems with varied experimental conditions and computation, including the collaboration with Dr. Veena Tikare of Sandia National Laboratory with a hybrid computation method at the ending this grant. A more detailed relationship between nanostructure formation and experimental conditions will be revealed with our continued efforts.

  5. Towards nanoscale multiplexing with parity-time symmetric plasmonic coaxial waveguides

    CERN Document Server

    Alaeian, Hadiseh; Jankovic, Vladan; Lawrence, Mark; Dionne, Jennifer A

    2016-01-01

    We theoretically investigate a nanoscale mode-division multiplexing scheme based on parity-time (PT) symmetric coaxial plasmonic waveguides. Coaxial waveguides support paired degenerate modes corresponding to distinct orbital angular momentum states. PT symmetric inclusions of gain and loss break the degeneracy of the paired modes and create new hybrid modes without orbital angular momentum. This process can be made thresholdless by matching the mode order with the number of gain and loss sections within the coaxial ring. Using both a Hamiltonian formulation and degenerate perturbation theory, we show how the wavevectors and fields evolve with increased loss/gain and derive sufficient conditions for thresholdless transitions. As a multiplexing filter, this PT symmetric coaxial waveguide could help double density rates in on-chip nanophotonic networks.

  6. Imaging nanoscale lattice variations by machine learning of x-ray diffraction microscopy data

    Science.gov (United States)

    Laanait, Nouamane; Zhang, Zhan; Schlepütz, Christian M.

    2016-09-01

    We present a novel methodology based on machine learning to extract lattice variations in crystalline materials, at the nanoscale, from an x-ray Bragg diffraction-based imaging technique. By employing a full-field microscopy setup, we capture real space images of materials, with imaging contrast determined solely by the x-ray diffracted signal. The data sets that emanate from this imaging technique are a hybrid of real space information (image spatial support) and reciprocal lattice space information (image contrast), and are intrinsically multidimensional (5D). By a judicious application of established unsupervised machine learning techniques and multivariate analysis to this multidimensional data cube, we show how to extract features that can be ascribed physical interpretations in terms of common structural distortions, such as lattice tilts and dislocation arrays. We demonstrate this ‘big data’ approach to x-ray diffraction microscopy by identifying structural defects present in an epitaxial ferroelectric thin-film of lead zirconate titanate.

  7. HYBRID FLOW PATTERN AND ITS APPLICATION IN NETWORK RECONFIGURATION%综合潮流模式及其在配电系统网络重构中的应用

    Institute of Scientific and Technical Information of China (English)

    雷健生; 邓佑满; 张伯明

    2001-01-01

    Distribution network reconfiguration is a multi-objective optimization problem in real-time operation environment. An effective method is developed based on the concept of hybrid flow pattern, where both secure and economic objectives are under considerations at the same time. The proposed method can be applied to unbalanced systems. Both unifying objective function approach and parametric approach, which are efficient techniques in solving the problem of multiple criteria decision-making (MCDM), are used to search for more practical solutions. A computer program has been developed based on this methodology. Numerical tests have shown that this methodology is valid and efficient.%针对配电系统网络重构的多目标实时优化问题,提出了一种基于综合潮流模式的网络重构算法,它可以同时考虑安全性和经济性这2两个可能冲突的目标。该算法充分考虑了配电系统负荷的三相不平衡特性。同时,应用了数学上处理多目标决策问题所常用的目标归一化法和参数变动法,从而可以得到更多的有效重构策略。该算法的实际计算结果表明,提出的理论是正确的、有效的。

  8. An Improved Hybrid Method for Inverse Obstacle Scattering Problems

    Institute of Scientific and Technical Information of China (English)

    LIU JUAN; MA FU-MING

    2011-01-01

    An improved hybrid method is introduced in this paper as a numerical method to reconstruct the scatterer by far-field pattern for just one incident direction with unknown physical properties of the scatterer.The improved hybrid method inherits the idea of the hybrid method by Kress and Serranho which is a combination of Newton and decomposition method,and it improves the hybrid method by introducing a general boundary condition.The numerical experiments show the feasibility of this method.

  9. Reductive Dechlorination of p-Chlorophenol by Nanoscale Iron

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To investigate reductive dechlorination of 4-chlorophenol (4-CP) by nanoscale Fe0 under different conditions.Methods Nanoscale Fe0 was synthesized by using reductive method. 4-CP and its intermediate products were analyzed by HPLC. Chlorine ion was quantified with DX-100 ion chromatograph. Nano-iron particles were observed under a FEI Quanta 200 FEG environmental scanning electron microscope (ESEM).Results The size of the particles was in the range of 10-100 nm. The nano-iron particles could reduce 4-CP effectively. The initial concentration of 4-CP increased with the decrease of the relative degradation rate,whereas the reduced amount of 4-CP increased. Temperature could influence both the dechlorination rate and the reaction pathway. Moreover,the stability and durability of nanoscale Fe0 was evaluated through batch studies over extended periods of time.Conclusion The nanoscale Fe0 can be used for sustainable treatment of contaminants in groundwater.

  10. Geometrical tuning of nanoscale split-ring resonators

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Kristensen, Anders; Xiao, Sanshui;

    2010-01-01

    We investigate the capacitance tuning of nanoscale split-ring resonators. An LC-model predicts a simple dependence of resonance frequency on slit aspect ratio. Experimental and numerical data follow the predictions of the LC-model....

  11. Manufacturing of Superhydrophobic Surfaces with Nanoscale and Microscale Features

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-06-01

    This factsheet describes a research project that will develop a technology that will enable nanoscale and microscale superhydrophobic (SHP) features to be imaged onto surfaces for the high-volume manufacturing of water-repellent components and coatings.

  12. Nanoscale Test Strips for Multiplexed Blood Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of our nanoscale test strips, or nanostrips, is to provide rapid, low-cost, powerful multiplexed analyses in a diminutive form so that whole body health...

  13. Democratization of Nanoscale Imaging and Sensing Tools Using Photonics.

    Science.gov (United States)

    McLeod, Euan; Wei, Qingshan; Ozcan, Aydogan

    2015-07-07

    Providing means for researchers and citizen scientists in the developing world to perform advanced measurements with nanoscale precision can help to accelerate the rate of discovery and invention as well as improve higher education and the training of the next generation of scientists and engineers worldwide. Here, we review some of the recent progress toward making optical nanoscale measurement tools more cost-effective, field-portable, and accessible to a significantly larger group of researchers and educators. We divide our review into two main sections: label-based nanoscale imaging and sensing tools, which primarily involve fluorescent approaches, and label-free nanoscale measurement tools, which include light scattering sensors, interferometric methods, photonic crystal sensors, and plasmonic sensors. For each of these areas, we have primarily focused on approaches that have either demonstrated operation outside of a traditional laboratory setting, including for example integration with mobile phones, or exhibited the potential for such operation in the near future.

  14. Hybrid microelectronic technology

    Science.gov (United States)

    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.

  15. Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Rajendra Bordia

    2009-07-31

    The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an economical and immediate solution to this problem. Good high temperature corrosion protection ceramic coatings for metallic structures must have a set of properties that are difficult to achieve using established processing techniques. The required properties include ease of coating complex shapes, low processing temperatures, thermal expansion match with metallic structures and good mechanical and chemical properties. Nanoscale reinforced composite coatings in which the matrix is derived from preceramic polymers have the potential to meet these requirements. The research was focused on developing suitable material systems and

  16. Quantum Materials at the Nanoscale - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Stephen Lance [Univ. of Illinois, Urbana, IL (United States). Dept. of Physics

    2016-01-11

    The central aim of the Quantum Materials at the Nanoscale (QMN) cluster was to understand and control collective behavior involving the interplay of spins, orbitals, and charges, which governs many scientifically interesting and technologically important phenomena in numerous complex materials. Because these phenomena involve various competing interactions, and influence properties on many different length and energy scales in complex materials, tackling this important area of study motivated a collaborative effort that combined the diverse capabilities of QMN cluster experimentalists, the essential theoretical analysis provided by QMN cluster theorists, and the outstanding facilities and staff of the FSMRL. During the funding period 2007-2014, the DOE cluster grant for the Quantum Materials at the Nanoscale (QMN) cluster supported, at various times, 15 different faculty members (14 in Physics and 1 in Materials Science and Engineering), 7 postdoctoral research associates, and 57 physics and materials science PhD students. 41 of these PhD students have since graduated and have gone on to a variety of advanced technical positions at universities, industries, and national labs: 25 obtained postdoctoral positions at universities (14), industrial labs (2 at IBM), DOE national facilities (3 at Argonne National Laboratory, 1 at Brookhaven National Lab, 1 at Lawrence Berkeley National Lab, and 1 at Sandia National Lab), and other federal facilities (2 at NIST); 13 took various industrial positions, including positions at Intel (5), Quantum Design (1), Lasque Industries (1), Amazon (1), Bloomberg (1), and J.P. Morgan (1). Thus, the QMN grant provided the essential support for training a large number of technically advanced personnel who have now entered key national facilities, industries, and institutions. Additionally, during the period 2007-2015, the QMN cluster produced 159 publications (see pages 14-23), including 23 papers published in Physical Review Letters; 16

  17. Nanoscale Probe of Magnetism Based on Artificial Atoms in Diamond

    Science.gov (United States)

    2014-07-18

    AFRL-OSR-VA-TR-2014-0165 ( YIP 11) Nanoscale probe of magnetism based on artificial atoms in diamond Ania Bleszynski Jayich UNIVERSITY OF CALIFORNIA...center Ania Bleszynski Jayihc (805) 893 8089 AFOSR   YIP  Report     Ania  Bleszynski  Jayich   Nanoscale probe of magnetism based on...dramatically affected by proximal Gd ions. Gd ions are commonly used spin labels for biological imaging. AFOSR   YIP  Report     Ania

  18. Nanoscale Measurements of Magnetism & Spin Coherence in Semiconductors

    Science.gov (United States)

    2016-06-14

    2015 Approved for Public Release; Distribution Unlimited Final Report: Nanoscale Measurements of Magnetism & Spin Coherence in Semiconductors The...floor Princeton, NJ 08544 -2020 31-Jul-2015 ABSTRACT Final Report: Nanoscale Measurements of Magnetism & Spin Coherence in Semiconductors Report Title...Si-on-insultor devices. These SOI devices will provide the samples required for study of spin coherence at a single spin level in a semiconductor

  19. Nanoscale volcanoes: accretion of matter at ion-sculpted nanopores.

    Science.gov (United States)

    Mitsui, Toshiyuki; Stein, Derek; Kim, Young-Rok; Hoogerheide, David; Golovchenko, J A

    2006-01-27

    We demonstrate the formation of nanoscale volcano-like structures induced by ion-beam irradiation of nanoscale pores in freestanding silicon nitride membranes. Accreted matter is delivered to the volcanoes from micrometer distances along the surface. Volcano formation accompanies nanopore shrinking and depends on geometrical factors and the presence of a conducting layer on the membrane's back surface. We argue that surface electric fields play an important role in accounting for the experimental observations.

  20. Fundamentals of nanoscale polymer-protein interactions and potential contributions to solid-state nanobioarrays.

    Science.gov (United States)

    Hahm, Jong-in

    2014-08-26

    Protein adsorption onto polymer surfaces is a very complex, ubiquitous, and integrated process, impacting essential areas of food processing and packaging, health devices, diagnostic tools, and medical products. The nature of protein-surface interactions is becoming much more complicated with continuous efforts toward miniaturization, especially for the development of highly compact protein detection and diagnostic devices. A large body of literature reports on protein adsorption from the perspective of ensemble-averaged behavior on macroscopic, chemically homogeneous, polymeric surfaces. However, protein-surface interactions governing the nanoscale size regime may not be effectively inferred from their macroscopic and microscopic characteristics. Recently, research efforts have been made to produce periodically arranged, nanoscopic protein patterns on diblock copolymer surfaces solely through self-assembly. Intriguing protein adsorption phenomena are directly probed on the individual biomolecule level for a fundamental understanding of protein adsorption on nanoscale surfaces exhibiting varying degrees of chemical heterogeneity. Insight gained from protein assembly on diblock copolymers can be effectively used to control the surface density, conformation, orientation, and biofunctionality of prebound proteins in highly miniaturized applications, now approaching the nanoscale. This feature article will highlight recent experimental and theoretical advances made on these fronts while focusing on single-biomolecule-level investigations of protein adsorption behavior combined with surface chemical heterogeneity on the length scale commensurate with a single protein. This article will also address advantages and challenges of the self-assembly-driven patterning technology used to produce protein nanoarrays and its implications for ultrahigh density, functional, and quantifiable protein detection in a highly miniaturized format.