WorldWideScience

Sample records for develop nanoscale structures

  1. 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...... to oppose the formation of structures. Our simulations suggest that Turing patterns can be a method of self-organization at a length scale of down to 20 molecular diameters...

  2. 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.

  3. Study of nanoscale structural biology using advanced particle beam microscopy

    Science.gov (United States)

    Boseman, Adam J.

    This work investigates developmental and structural biology at the nanoscale using current advancements in particle beam microscopy. Typically the examination of micro- and nanoscale features is performed using scanning electron microscopy (SEM), but in order to decrease surface charging, and increase resolution, an obscuring conductive layer is applied to the sample surface. As magnification increases, this layer begins to limit the ability to identify nanoscale surface structures. A new technology, Helium Ion Microscopy (HIM), is used to examine uncoated surface structures on the cuticle of wild type and mutant fruit flies. Corneal nanostructures observed with HIM are further investigated by FIB/SEM to provide detailed three dimensional information about internal events occurring during early structural development. These techniques are also used to reconstruct a mosquito germarium in order to characterize unknown events in early oogenesis. Findings from these studies, and many more like them, will soon unravel many of the mysteries surrounding the world of developmental biology.

  4. Dynamic structural disorder in supported nanoscale catalysts

    International Nuclear Information System (INIS)

    Rehr, J. J.; Vila, F. D.

    2014-01-01

    We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale

  5. Dynamic structural disorder in supported nanoscale catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rehr, J. J.; Vila, F. D. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States)

    2014-04-07

    We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale.

  6. 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.

  7. The Nanoscale Observation of the Three-Dimensional Structures of Neurosynapses, Membranous Conjunctions Between Cultured Hippocampal Neurons and Their Significance in the Development of Epilepsy.

    Science.gov (United States)

    Sun, Lan; Jiang, Shuang; Tang, Xianhua; Zhang, Yingge; Qin, Luye; Jiang, Xia; Yu, Albert Cheung Hoi

    2016-12-01

    The nanoscale three-dimensional structures of neurosynapses are unknown, and the neuroanatomical basis of epilepsy remains to be elucidated. Here, we studied the nanoscale three-dimensional synapses between hippocampal neurons, and membranous conjunctions between neurons were found with atomic force microscopy (AFM) and confirmed by transmission electron microscope (TEM), and their pathophysiological significance was primarily investigated. The neurons and dendrites were marked by MAP-2, axons by neurofilament 200, and synapses by synapsin I immunological staining. In the synapsin I-positive neurite ends of the neurons positively stained with MAP-2 and neurofilament 200, neurosynapses with various nanoscale morphology and structure could be found by AFM. The neurosynapses had typical three-dimensional structures of synaptic triplet including the presynaptic neurite end, synaptic cleft of 30 ∼ 40 in chemical synapses and 2 ∼ 6 nm in electrical ones, the postsynaptic neurite or dendrite spine, the typical neurite end button, the distinct pre- and postsynaptic membranes, and the obvious thickening of the postsynaptic membranes or neurites. Some membranous connections including membrane-like junctions (MLJ) and fiber-tube links (FTL) without triplet structures and cleft were found between neurons. The development frequencies of the two membranous conjunctions increased while those of the synaptic conjunctions decreased between the neurons from Otx1 knock-out mice in comparison with those between the neurons from normal mice. These results suggested that the neuroanatomical basis of Otx1 knock-out epilepsy is the combination of the decreased synaptic conjunctions and the increased membranous conjunctions.

  8. Probing defect and magnetic structures on the nanoscale

    OpenAIRE

    Kallis, Alexis

    2010-01-01

    This thesis reports on experimental research on structural defects and magnetic species on the nanoscale. The latter project involved considerable development work on the production of a spin-polarised mono-energetic positron beam. The construction of the system is described through various trial steps with emphasis on the methods of maximum practical polarization of the positron beam and of electrons in the sample with the smallest possible loss of beam intensity. A new sodium-22 source caps...

  9. 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.

  10. Nanoscale array structures suitable for surface enhanced raman scattering and methods related thereto

    Science.gov (United States)

    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.

  11. 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

    2015-07-14

    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.

  12. Development of Nanoscale Graphitic Devices and The Transport Characterization

    International Nuclear Information System (INIS)

    Gunasekaran, Venugopal

    2011-02-01

    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

  13. Investigation of Short Channel Effect on Vertical Structures in Nanoscale MOSFET

    Directory of Open Access Journals (Sweden)

    Munawar A. Riyadi

    2009-12-01

    Full Text Available The recent development of MOSFET demands innovative approach to maintain the scaling into nanoscale dimension. This paper focuses on the physical nature of vertical MOSFET in nanoscale regime. Vertical structure is one of the promising devices in further scaling, with relaxed-lithography feature in the manufacture. The comparison of vertical and lateral MOSFET performance for nanoscale channel length (Lch is demonstrated with the help of numerical tools. The evaluation of short channel effect (SCE parameters, i.e. threshold voltage roll-off, subthreshold swing (SS, drain induced barrier lowering (DIBL and leakage current shows the considerable advantages as well as its thread-off in implementing the structure, in particular for nanoscale regime.

  14. Nanoscale spin-dependent transport of electrons and holes in Si-ferromagnet structures

    NARCIS (Netherlands)

    Ul Haq, E.

    Given the rapid development of magnetic data storage and spin-electronics into the realm of nanotechnology, the understanding of the spin-dependent electronic transport and switching behavior of magnetic structures at the nanoscale is an important issue. We have developed spin-sensitive techniques

  15. On ripples and rafts: Curvature induced nanoscale structures in lipid membranes

    International Nuclear Information System (INIS)

    Schmid, Friederike; Dolezel, Stefan; Meinhardt, Sebastian; Lenz, Olaf

    2014-01-01

    We develop an elastic theory that predicts the spontaneous formation of nanoscale structures in lipid bilayers which locally phase separate between two phases with different spontaneous monolayer curvature. The theory rationalizes in a unified manner the observation of a variety of nanoscale structures in lipid membranes: Rippled states in one-component membranes, lipid rafts in multicomponent membranes. Furthermore, we report on recent observations of rippled states and rafts in simulations of a simple coarse-grained model for lipid bilayers, which are compatible with experimental observations and with our elastic model

  16. Nanoscale surface topographies for structural colors

    DEFF Research Database (Denmark)

    Clausen, Jeppe Sandvik

    The thesis describes and demonstrates the possibilities for utilization of structural colors in mass fabricated plastic products as replacement for or in combination with pigments and inks. The motivation is the possible advantages related to re-cycling and re-use of plastic by limiting the number......-polymer interface is suppressed. This improves the ability to see through a clear plastic in the presence of specular reflection. The tapered nanostructures are also utilized to enhance the chroma of pigmented polymers. Larger tapered structures fabricated in a similar manor are shown to work as color filters....... Through an experimental study is the color of the transmitted light linked directly to the random topography of the surface by use of diffraction theory. The color effects from periodic structures and how these might be employed to create bright colors are investigated. This is done both for opaque...

  17. Imaging the Nanoscale Band Structure of Topological Sb

    OpenAIRE

    Soumyanarayanan, Anjan; Yee, Michael M.; He, Yang; Lin, Hsin; Gardner, Dillon R.; Bansil, Arun; Lee, Young S.; Hoffman, Jennifer E.

    2013-01-01

    Many promising building blocks of future electronic technology - including non-stoichiometric compounds, strongly correlated oxides, and strained or patterned films - are inhomogeneous on the nanometer length scale. Exploiting the inhomogeneity of such materials to design next-generation nanodevices requires a band structure probe with nanoscale spatial resolution. To address this demand, we report the first simultaneous observation and quantitative reconciliation of two candidate probes - La...

  18. 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.

  19. Organisation and Control of Nanoscale Structures on Au(111)

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Chi, Qijin; Andersen, Jens Enevold Thaulov

    2001-01-01

    system is IDe arnino acid cystine in the adsorbed state. Af ter dissociation of its disulfide band cystine farms a highly ordered pattem controlled by adsorption via IDe liberated sulfur atoms and intermolecular hydrogen bonding. Further organisation at three different leveis by lateral interactions can...... constitutes a new case for the lise of in situ STM as a tool for manufacturing nanoscale pit structures on IDe Au(lll) surface at small bias voltage. Individually and in combination these data hold perspectives for preparation of atornically planar electrochernical surfaces willi controlled functionalisation...

  20. Fabrication of complex nanoscale structures on various substrates

    Science.gov (United States)

    Han, Kang-Soo; Hong, Sung-Hoon; Lee, Heon

    2007-09-01

    Polymer based complex nanoscale structures were fabricated and transferred to various substrates using reverse nanoimprint lithography. To facilitate the fabrication and transference of the large area of the nanostructured layer to the substrates, a water-soluble polyvinyl alcohol mold was used. After generation and transference of the nanostructured layer, the polyvinyl alcohol mold was removed by dissolving in water. A residue-free, UV-curable, glue layer was formulated and used to bond the nanostructured layer onto the substrates. As a result, nanometer scale patterned polymer layers were bonded to various substrates and three-dimensional nanostructures were also fabricated by stacking of the layers.

  1. Investigations on a nano-scale periodical waveguide structure taking surface plasmon polaritons into consideration

    International Nuclear Information System (INIS)

    Liu Weihao; Zhong Renbin; Zhou Jun; Zhang Yaxin; Hu Min; Liu Shenggang

    2012-01-01

    Detailed theoretical analysis and computer simulations on the electromagnetic characteristics of a nano-scale periodical waveguide structure, taking surface plasmon polaritons (SPPs) into consideration, are carried out in this paper. The results show that SPPs will significantly influence the electromagnetic characteristics of the structure. When the operation frequency is in a certain band—the ‘radial confinement band’, neither radial surface plasmon waves nor guided waves, which both will lead to radial energy loss, can be excited in the structure. And the electromagnetic waves are completely confined within the longitudinal waveguide and propagate along it with little attenuation. The radial energy loss is then significantly reduced. These results are of great significance not only for increasing the efficiency of the radiation sources based on the nano-scale periodical waveguide structure but also for the development of high-efficiency waveguides and wide-band filters in the infrared and visible light regimes. (paper)

  2. Self-assembled domain structures: From micro- to nanoscale

    Directory of Open Access Journals (Sweden)

    Vladimir Shur

    2015-06-01

    Full Text Available The recent achievements in studying the self-assembled evolution of micro- and nanoscale domain structures in uniaxial single crystalline ferroelectrics lithium niobate and lithium tantalate have been reviewed. The results obtained by visualization of static domain patterns and kinetics of the domain structure by different methods from common optical microscopy to more sophisticated scanning probe microscopy, scanning electron microscopy and confocal Raman microscopy, have been discussed. The kinetic approach based on various nucleation processes similar to the first-order phase transition was used for explanation of the domain structure evolution scenarios. The main mechanisms of self-assembling for nonequilibrium switching conditions caused by screening ineffectiveness including correlated nucleation, domain growth anisotropy, and domain–domain interaction have been considered. The formation of variety of self-assembled domain patterns such as fractal-type, finger and web structures, broad domain boundaries, and dendrites have been revealed at each of all five stages of domain structure evolution during polarization reversal. The possible applications of self-assembling for micro- and nanodomain engineering were reviewed briefly. The review covers mostly the results published by our research group.

  3. Effects of structural modification on reliability of nanoscale nitride HEMTs

    Science.gov (United States)

    Gaddipati, Vamsi Mohan

    AlGaN based nanoscale high-electron-mobility transistors (HEMTs) are the next generation of transistor technology that features the unique combination of higher power, wider bandwidth, low noise, higher efficiency, and temperature/radiation hardness than conventional AlGaAs and Si based technologies. However, as evidenced by recent stress tests, reliability of these devices (characterized by a gradual decrease in the output current/power leading to failure of the device in just tens of hours of operation) remains a major concern. Although, in these tests, physical damages were clearly visible in the device, the root cause and nature of these damages have not yet been fully assessed experimentally. Therefore, a comprehensive theoretical study of the physical mechanisms responsible for degradation of AlGaN HEMTs is essential before these devices are deployed in targeted applications. The main objective of the proposed research is to computationally investigate how degradation of state-of-the-art nanoscale AlGaN HEMTs is governed by an intricate and dynamical coupling of thermo-electromechanical processes at different length (atoms-to-transistor) and time (femtosecondto- hours) scales while operating in high voltage, large mechanical, and high temperature/radiation stresses. This work centers around a novel hypotheses as follows: High voltage applied to AlGaN HEMT causes excessive internal heat dissipation, which triggers gate metal diffusion into the semiconducting barrier layer and structural modifications (defect ii formation) leading to diminished polarization induced charge density and output current. Since the dynamical system to be studied is complex, chaotic (where the evolution rule is guided by atomicity of the underlying material), and involve coupled physical processes, an in-house multiscale simulator (QuADS 3-D) has been employed and augmented, where material parameters are obtained atomistically using firstprinciples, structural relaxation and defect

  4. Monolithic integration of nanoscale tensile specimens and MEMS structures

    International Nuclear Information System (INIS)

    Yilmaz, Mehmet; Kysar, Jeffrey W

    2013-01-01

    Nanoscale materials often have stochastic material properties due to a random distribution of material defects and an insufficient number of defects to ensure a consistent average mechanical response. Current methods to measure the mechanical properties employ MEMS-based actuators. The nanoscale specimens are typically mounted manually onto the load platform, so the boundary conditions have random variations, complicating the experimental measurement of the intrinsic stochasticity of the material properties. Here we show methods for monolithic integration of a nanoscale specimen co-fabricated with the loading platform. The nanoscale specimen is gold with dimensions of ∼40 nm thickness, 350 ± 50 nm width, and 7 μm length and the loading platform is an interdigitated electrode electrostatic actuator. The experiment is performed in a scanning electron microscope and digital image correlation is employed to measure displacements to determine stress and strain. The ultimate tensile strength of the nanocrystalline nanoscale specimen approaches 1 GPa, consistent with measurements made by other nanometer scale sample characterization methods on other material samples at the nanometer scale, as well as gold samples at the nanometer scale. The batch-compatible microfabrication method can be used to create nominally identical nanoscale specimens and boundary conditions for a broad range of materials. (paper)

  5. The development, characterization, and application of biomimetic nanoscale enzyme immobilization

    Science.gov (United States)

    Haase, Nicholas R.

    The utilization of enzymes is of interest for applications such as biosensors and biofuel cells. Immobilizing enzymes provides a means to develop these applications. Previous immobilization efforts have been accomplished by exposing surfaces on which silica-forming molecules are present to solutions containing an enzyme and a silica precursor. This approach leads to the enzyme being entrapped in a matrix three orders of magnitude larger than the enzyme itself, resulting in low retention of enzyme activity. The research herein introduces a method for the immobilization of enzymes during the layer-by-layer buildup of Si-O and Ti-O coatings which are nanoscale in thickness. This approach is an application of a peptide-induced mineral deposition method developed in the Sandhage and Kroger groups, and it involves the alternating exposure of a surface to solutions containing the peptide protamine and then an aqueous precursor solution of silicon- or titanium-oxide at near-neutral pH. A method has been developed that enables in situ immobilization of enzymes in the protamine/mineral oxide coatings. Depending on the layer and mineral (silica or titania) within which the enzyme is incorporated, the resulting multilayer biocatalytic hybrid materials retain 20 -- 100% of the enzyme activity. Analyses of kinetic properties of the immobilized enzyme, coupled with characterization of physical properties of the mineral-bearing layers (thickness, porosity, pore size distribution), indicates that the catalytic activities of the enzymes immobilized in the different layers are largely determined by substrate diffusion. The enzyme was also found to be substantially stabilized against heat-induced denaturation and largely protected from proteolytic attack. These functional coatings are then developed for use as antimicrobial materials. Glucose oxidase, which catalyzes production of the cytotoxic agent hydrogen peroxide, was immobilized with silver nanoparticles, can release

  6. Potential of silicon nanowires structures as nanoscale piezoresistors in mechanical sensors

    International Nuclear Information System (INIS)

    Messina, M; Njuguna, J

    2012-01-01

    This paper presents the design of a single square millimeter 3-axial accelerometer for bio-mechanics measurements that exploit the potential of silicon nanowires structures as nanoscale piezoresistors. The main requirements of this application are miniaturization and high measurement accuracy. Nanowires as nanoscale piezoresistive devices have been chosen as sensing element, due to their high sensitivity and miniaturization achievable. By exploiting the electro-mechanical features of nanowires as nanoscale piezoresistors, the nominal sensor sensitivity is overall boosted by more than 30 times. This approach allows significant higher accuracy and resolution with smaller sensing element in comparison with conventional devices without the need of signal amplification.

  7. Polyamide membranes with nanoscale Turing structures for water purification

    Science.gov (United States)

    Tan, Zhe; Chen, Shengfu; Peng, Xinsheng; Zhang, Lin; Gao, Congjie

    2018-05-01

    The emergence of Turing structures is of fundamental importance, and designing these structures and developing their applications have practical effects in chemistry and biology. We use a facile route based on interfacial polymerization to generate Turing-type polyamide membranes for water purification. Manipulation of shapes by control of reaction conditions enabled the creation of membranes with bubble or tube structures. These membranes exhibit excellent water-salt separation performance that surpasses the upper-bound line of traditional desalination membranes. Furthermore, we show the existence of high water permeability sites in the Turing structures, where water transport through the membranes is enhanced.

  8. Nano-scale structure in membranes in relation to enzyme action - computer simulation vs. experiment

    DEFF Research Database (Denmark)

    Høyrup, P.; Jørgensen, Kent; Mouritsen, O.G.

    2002-01-01

    There is increasing theoretical and experimental evidence indicating that small-scale domain structure and dynamical heterogeneity develop in lipid membranes as a consequence of the the underlying phase transitions and the associated density and composition fluctuations. The relevant coherence...... lengths are in the nano-meter range. The nano-scale structure is believed to be important for controlling the activity of enzymes, specifically phospholipases, which act at bilayer membranes. We propose here a lattice-gas statistical mechanical model with appropriate dynamics to account for the non......-equilibrium action of the enzyme phospholipase A(2) which hydrolyses lipid-bilayer substrates. The resulting product molecules are assumed to induce local variations in the membrane interfacial pressure. Monte Carlo simulations of the non-equilibrium properties of the model for one-component as well as binary lipid...

  9. Investigation of nanoscale structures by small-angle X-ray scattering in a radiochromic dosimeter

    DEFF Research Database (Denmark)

    Skyt, Peter Sandegaard; Jensen, Grethe Vestergaard; Wahlstedt, Isak Hannes

    2014-01-01

    This study examines the nanoscale structures in a radiochromic dosimeter that was based on leuco-malachite-green dye and the surfactant sodium dodecyl sulfate (SDS) suspended in a gelatin matrix. Small-angle X-ray scattering was used to investigate the structures of a range of compositions...

  10. From Lab to Fab: Developing a Nanoscale Delivery Tool for Scalable Nanomanufacturing

    Science.gov (United States)

    Safi, Asmahan A.

    The emergence of nanomaterials with unique properties at the nanoscale over the past two decades carries a capacity to impact society and transform or create new industries ranging from nanoelectronics to nanomedicine. However, a gap in nanomanufacturing technologies has prevented the translation of nanomaterial into real-world commercialized products. Bridging this gap requires a paradigm shift in methods for fabricating structured devices with a nanoscale resolution in a repeatable fashion. This thesis explores the new paradigms for fabricating nanoscale structures devices and systems for high throughput high registration applications. We present a robust and scalable nanoscale delivery platform, the Nanofountain Probe (NFP), for parallel direct-write of functional materials. The design and microfabrication of NFP is presented. The new generation addresses the challenges of throughput, resolution and ink replenishment characterizing tip-based nanomanufacturing. To achieve these goals, optimized probe geometry is integrated to the process along with channel sealing and cantilever bending. The capabilities of the newly fabricated probes are demonstrated through two type of delivery: protein nanopatterning and single cell nanoinjection. The broad applications of the NFP for single cell delivery are investigated. An external microfluidic packaging is developed to enable delivery in liquid environment. The system is integrated to a combined atomic force microscope and inverted fluorescence microscope. Intracellular delivery is demonstrated by injecting a fluorescent dextran into Hela cells in vitro while monitoring the injection forces. Such developments enable in vitro cellular delivery for single cell studies and high throughput gene expression. The nanomanufacturing capabilities of NFPs are explored. Nanofabrication of carbon nanotube-based electronics presents all the manufacturing challenges characterizing of assembling nanomaterials precisely onto devices. The

  11. Controlling Non-Equilibrium Structure Formation on the Nanoscale.

    Science.gov (United States)

    Buchmann, Benedikt; Hecht, Fabian Manfred; Pernpeintner, Carla; Lohmueller, Theobald; Bausch, Andreas R

    2017-12-06

    Controlling the structure formation of gold nanoparticle aggregates is a promising approach towards novel applications in many fields, ranging from (bio)sensing to (bio)imaging to medical diagnostics and therapeutics. To steer structure formation, the DNA-DNA interactions of DNA strands that are coated on the surface of the particles have become a valuable tool to achieve precise control over the interparticle potentials. In equilibrium approaches, this technique is commonly used to study particle crystallization and ligand binding. However, regulating the structural growth processes from the nano- to the micro- and mesoscale remains elusive. Here, we show that the non-equilibrium structure formation of gold nanoparticles can be stirred in a binary heterocoagulation process to generate nanoparticle clusters of different sizes. The gold nanoparticles are coated with sticky single stranded DNA and mixed at different stoichiometries and sizes. This not only allows for structural control but also yields access to the optical properties of the nanoparticle suspensions. As a result, we were able to reliably control the kinetic structure formation process to produce cluster sizes between tens of nanometers up to micrometers. Consequently, the intricate optical properties of the gold nanoparticles could be utilized to control the maximum of the nanoparticle suspension extinction spectra between 525 nm and 600 nm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. On the relationship between the dynamic behavior and nanoscale staggered structure of the bone

    Science.gov (United States)

    Qwamizadeh, Mahan; Zhang, Zuoqi; Zhou, Kun; Zhang, Yong Wei

    2015-05-01

    Bone, a typical load-bearing biological material, composed of ordinary base materials such as organic protein and inorganic mineral arranged in a hierarchical architecture, exhibits extraordinary mechanical properties. Up to now, most of previous studies focused on its mechanical properties under static loading. However, failure of the bone occurs often under dynamic loading. An interesting question is: Are the structural sizes and layouts of the bone related or even adapted to the functionalities demanded by its dynamic performance? In the present work, systematic finite element analysis was performed on the dynamic response of nanoscale bone structures under dynamic loading. It was found that for a fixed mineral volume fraction and unit cell area, there exists a nanoscale staggered structure at some specific feature size and layout which exhibits the fastest attenuation of stress waves. Remarkably, these specific feature sizes and layouts are in excellent agreement with those experimentally observed in the bone at the same scale, indicating that the structural size and layout of the bone at the nanoscale are evolutionarily adapted to its dynamic behavior. The present work points out the importance of dynamic effect on the biological evolution of load-bearing biological materials.

  13. Computational strategies for the automated design of RNA nanoscale structures from building blocks using NanoTiler.

    Science.gov (United States)

    Bindewald, Eckart; Grunewald, Calvin; Boyle, Brett; O'Connor, Mary; Shapiro, Bruce A

    2008-10-01

    One approach to designing RNA nanoscale structures is to use known RNA structural motifs such as junctions, kissing loops or bulges and to construct a molecular model by connecting these building blocks with helical struts. We previously developed an algorithm for detecting internal loops, junctions and kissing loops in RNA structures. Here we present algorithms for automating or assisting many of the steps that are involved in creating RNA structures from building blocks: (1) assembling building blocks into nanostructures using either a combinatorial search or constraint satisfaction; (2) optimizing RNA 3D ring structures to improve ring closure; (3) sequence optimisation; (4) creating a unique non-degenerate RNA topology descriptor. This effectively creates a computational pipeline for generating molecular models of RNA nanostructures and more specifically RNA ring structures with optimized sequences from RNA building blocks. We show several examples of how the algorithms can be utilized to generate RNA tecto-shapes.

  14. Computational strategies for the automated design of RNA nanoscale structures from building blocks using NanoTiler☆

    Science.gov (United States)

    Bindewald, Eckart; Grunewald, Calvin; Boyle, Brett; O’Connor, Mary; Shapiro, Bruce A.

    2013-01-01

    One approach to designing RNA nanoscale structures is to use known RNA structural motifs such as junctions, kissing loops or bulges and to construct a molecular model by connecting these building blocks with helical struts. We previously developed an algorithm for detecting internal loops, junctions and kissing loops in RNA structures. Here we present algorithms for automating or assisting many of the steps that are involved in creating RNA structures from building blocks: (1) assembling building blocks into nanostructures using either a combinatorial search or constraint satisfaction; (2) optimizing RNA 3D ring structures to improve ring closure; (3) sequence optimisation; (4) creating a unique non-degenerate RNA topology descriptor. This effectively creates a computational pipeline for generating molecular models of RNA nanostructures and more specifically RNA ring structures with optimized sequences from RNA building blocks. We show several examples of how the algorithms can be utilized to generate RNA tecto-shapes. PMID:18838281

  15. Formation of nanoscale tungsten oxide structures and colouration ...

    Indian Academy of Sciences (India)

    The X-ray diffraction, together with transmission electron microscopic studies have revealed formation of regular polyhedral nanocrystalline ..... For molecular structure and orientation determination, the ... self-similarity within a complicated system. ..... Hummel R I 1997 Handbook of optical properties: Optics of small particles ...

  16. Structural and mechanical properties of glassy water in nanoscale confinement.

    Science.gov (United States)

    Lombardo, Thomas G; Giovambattista, Nicolás; Debenedetti, Pablo G

    2009-01-01

    We investigate the structure and mechanical properties of glassy water confined between silica-based surfaces with continuously tunable hydrophobicity and hydrophilicity by computing and analyzing minimum energy, mechanically stable configurations (inherent structures). The structured silica substrate imposes long-range order on the first layer of water molecules under hydrophobic confinement at high density (p > or = 1.0 g cm(-3)). This proximal layer is also structured in hydrophilic confinement at very low density (p approximately 0.4 g cm(-3)). The ordering of water next to the hydrophobic surface greatly enhances the mechanical strength of thin films (0.8 nm). This leads to a substantial stress anisotropy; the transverse strength of the film exceeds the normal strength by 500 MPa. The large transverse strength results in a minimum in the equation of state of the energy landscape that does not correspond to a mechanical instability, but represents disruption of the ordered layer of water next to the wall. In addition, we find that the mode of mechanical failure is dependent on the type of confinement. Under large lateral strain, water confined by hydrophilic surfaces preferentially forms voids in the middle of the film and fails cohesively. In contrast, water under hydrophobic confinement tends to form voids near the walls and fails by loss of adhesion.

  17. A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure

    OpenAIRE

    Sun, Xiaoxia; Uyama, Hiroshi

    2013-01-01

    A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructu...

  18. Role of Acoustoelectric Interaction in the Formation of Nanoscale Periodic Structures of Adsorbed Atoms

    Energy Technology Data Exchange (ETDEWEB)

    Peleshchak, R. M., E-mail: peleshchak@rambler.ru; Lazurchak, I. I.; Kuzyk, O. V.; Dan’kiv, O. O. [Ivan Franko Drohobych State Pedagogical University (Ukraine); Zegrya, G. G. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-03-15

    The role of acoustoelectric effects in the formation of nanoscale structures of adatoms, resulting from the self-consistent interaction of adatoms with a surface acoustic wave and the electronic subsystem, is studied for the case of charged and uncharged adatoms. It is shown that an increase in the doping level of a semiconductor with donor impurities at a fixed average adatom concentration results in an increase in the critical temperature below which self-organization processes occur.

  19. Modeling investigation of the stability and irradiation-induced evolution of nanoscale precipitates in advanced structural materials

    International Nuclear Information System (INIS)

    Wirth, Brian

    2015-01-01

    Materials used in extremely hostile environment such as nuclear reactors are subject to a high flux of neutron irradiation, and thus vast concentrations of vacancy and interstitial point defects are produced because of collisions of energetic neutrons with host lattice atoms. The fate of these defects depends on various reaction mechanisms which occur immediately following the displacement cascade evolution and during the longer-time kinetically dominated evolution such as annihilation, recombination, clustering or trapping at sinks of vacancies, interstitials and their clusters. The long-range diffusional transport and evolution of point defects and self-defect clusters drive a microstructural and microchemical evolution that are known to produce degradation of mechanical properties including the creep rate, yield strength, ductility, or fracture toughness, and correspondingly affect material serviceability and lifetimes in nuclear applications. Therefore, a detailed understanding of microstructural evolution in materials at different time and length scales is of significant importance. The primary objective of this work is to utilize a hierarchical computational modeling approach i) to evaluate the potential for nanoscale precipitates to enhance point defect recombination rates and thereby the self-healing ability of advanced structural materials, and ii) to evaluate the stability and irradiation-induced evolution of such nanoscale precipitates resulting from enhanced point defect transport to and annihilation at precipitate interfaces. This project will utilize, and as necessary develop, computational materials modeling techniques within a hierarchical computational modeling approach, principally including molecular dynamics, kinetic Monte Carlo and spatially-dependent cluster dynamics modeling, to identify and understand the most important physical processes relevant to promoting the ''selfhealing'' or radiation resistance in advanced

  20. Modeling investigation of the stability and irradiation-induced evolution of nanoscale precipitates in advanced structural materials

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, Brian [Univ. of Tennessee, Knoxville, TN (United States)

    2015-04-08

    Materials used in extremely hostile environment such as nuclear reactors are subject to a high flux of neutron irradiation, and thus vast concentrations of vacancy and interstitial point defects are produced because of collisions of energetic neutrons with host lattice atoms. The fate of these defects depends on various reaction mechanisms which occur immediately following the displacement cascade evolution and during the longer-time kinetically dominated evolution such as annihilation, recombination, clustering or trapping at sinks of vacancies, interstitials and their clusters. The long-range diffusional transport and evolution of point defects and self-defect clusters drive a microstructural and microchemical evolution that are known to produce degradation of mechanical properties including the creep rate, yield strength, ductility, or fracture toughness, and correspondingly affect material serviceability and lifetimes in nuclear applications. Therefore, a detailed understanding of microstructural evolution in materials at different time and length scales is of significant importance. The primary objective of this work is to utilize a hierarchical computational modeling approach i) to evaluate the potential for nanoscale precipitates to enhance point defect recombination rates and thereby the self-healing ability of advanced structural materials, and ii) to evaluate the stability and irradiation-induced evolution of such nanoscale precipitates resulting from enhanced point defect transport to and annihilation at precipitate interfaces. This project will utilize, and as necessary develop, computational materials modeling techniques within a hierarchical computational modeling approach, principally including molecular dynamics, kinetic Monte Carlo and spatially-dependent cluster dynamics modeling, to identify and understand the most important physical processes relevant to promoting the “selfhealing” or radiation resistance in advanced materials containing

  1. A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure.

    Science.gov (United States)

    Sun, Xiaoxia; Uyama, Hiroshi

    2013-10-04

    A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields.

  2. Structure Transformation and Coherent Interface in Large Lattice-Mismatched Nanoscale Multilayers

    Directory of Open Access Journals (Sweden)

    J. Y. Xie

    2013-01-01

    Full Text Available Nanoscale Al/W multilayers were fabricated by DC magnetron sputtering and characterized by transmission electron microscopy and high-resolution electron microscopy. Despite the large lattice mismatch and significantly different lattice structures between Al and W, a structural transition from face-centered cubic to body-centered cubic in Al layers was observed when the individual layer thickness was reduced from 5 nm to 1 nm, forming coherent Al/W interfaces. For potential mechanisms underlying the observed structure transition and forming of coherent interfaces, it was suggested that the reduction of interfacial energy and high stresses induced by large lattice-mismatch play a crucial role.

  3. Nanoscale structure and atomic disorder in the iron-based chalcogenides

    Directory of Open Access Journals (Sweden)

    Naurang Lal Saini

    2013-01-01

    Full Text Available The multiband iron-based superconductors have layered structure with a phase diagram characterized by a complex interplay of charge, spin and lattice excitations, with nanoscale atomic structure playing a key role in their fundamental electronic properties. In this paper, we briefly review nanoscale structure and atomic disorder in iron-based chalcogenide superconductors. We focus on the Fe(Se,S1−xTex (11-type and K0.8Fe1.6Se2 (122-type systems, discussing their local structure obtained by extended x-ray absorption fine structure. Local structure studies on the Fe(Se,S1−xTex system reveal clear nanoscale phase separation characterized by coexisting components of different atomic configurations, similar to the case of random alloys. In fact, the Fe–Se/S and Fe–Te distances in the ternary Fe(Se,S1−xTex are found to be closer to the respective distances in the binary FeSe/FeS and FeTe systems, showing significant divergence of the local structure from the average one. The observed features are characteristic of ternary random alloys, indicating breaking of the local symmetry in these materials. On the other hand, K0.8Fe1.6Se2 is known for phase separation in an iron-vacancy ordered phase and an in-plane compressed lattice phase. The local structure of these 122-type chalcogenides shows that this system is characterized by a large local disorder. Indeed, the experiments suggest a nanoscale glassy phase in K0.8Fe1.6Se2, with the superconductivity being similar to the granular materials. While the 11-type structure has no spacer layer, the 122-type structure contains intercalated atoms unlike the 1111-type REFeAsO (RE = rare earth oxypnictides, having well-defined REO spacer layers. It is clear that the interlayer atomic correlations in these iron-based superconducting structures play an important role in structural stability as well as superconductivity and magnetism.

  4. Nanoscale structural order from the atomic pair distribution function (PDF): There's plenty of room in the middle

    International Nuclear Information System (INIS)

    Billinge, Simon J.L.

    2008-01-01

    Emerging materials of scientific and technological interest are generally complex and often nanostructured: they have atomic orderings that extend on nanometer length-scales. These can be discrete nanoparticles; bulk crystals with nanoscale chemical or displacive order within them; mesoporous materials that are bulk materials containing nanoscale holes; and nanocomposites that are intimate heterogeneous mixtures of nano-sized constituents. As always, a quantitative knowledge of the atomic structure within these materials is a prerequisite to understanding and engineering their properties. Traditional crystallographic methods for obtaining this information break down at the nanoscale, sometimes referred to as 'the nanostructure problem'. We describe here some emerging methods for studying nanoscale structure. We present some examples of recent successes. Finally, we discuss future directions and opportunities and draw attention to limitations and potential problems. -

  5. Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Y., E-mail: maekawa.yasunari@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Quantum Beam Science Directorate, High Performance Polymer Group, 1233 Watanuki-Machi, Takasaki, Gunma-ken 370-1292 (Japan)

    2010-07-01

    Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

  6. Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

    International Nuclear Information System (INIS)

    Maekawa, Y.

    2010-01-01

    Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

  7. Correlative nanoscale 3D imaging of structure and composition in extended objects.

    Directory of Open Access Journals (Sweden)

    Feng Xu

    Full Text Available Structure and composition at the nanoscale determine the behavior of biological systems and engineered materials. The drive to understand and control this behavior has placed strong demands on developing methods for high resolution imaging. In general, the improvement of three-dimensional (3D resolution is accomplished by tightening constraints: reduced manageable specimen sizes, decreasing analyzable volumes, degrading contrasts, and increasing sample preparation efforts. Aiming to overcome these limitations, we present a non-destructive and multiple-contrast imaging technique, using principles of X-ray laminography, thus generalizing tomography towards laterally extended objects. We retain advantages that are usually restricted to 2D microscopic imaging, such as scanning of large areas and subsequent zooming-in towards a region of interest at the highest possible resolution. Our technique permits correlating the 3D structure and the elemental distribution yielding a high sensitivity to variations of the electron density via coherent imaging and to local trace element quantification through X-ray fluorescence. We demonstrate the method by imaging a lithographic nanostructure and an aluminum alloy. Analyzing a biological system, we visualize in lung tissue the subcellular response to toxic stress after exposure to nanotubes. We show that most of the nanotubes are trapped inside alveolar macrophages, while a small portion of the nanotubes has crossed the barrier to the cellular space of the alveolar wall. In general, our method is non-destructive and can be combined with different sample environmental or loading conditions. We therefore anticipate that correlative X-ray nano-laminography will enable a variety of in situ and in operando 3D studies.

  8. The Structure and Transport of Water and Hydrated Ions Within Hydrophobic, Nanoscale Channels

    International Nuclear Information System (INIS)

    Holt, J.K.; Herberg, J.L.; Wu, Y.; Schwegler, E.; Mehta, A.

    2009-01-01

    The purpose of this project includes an experimental and modeling investigation into water and hydrated ion structure and transport at nanomaterials interfaces. This is a topic relevant to understanding the function of many biological systems such as aquaporins that efficiently shuttle water and ion channels that permit selective transport of specific ions across cell membranes. Carbon nanotubes (CNT) are model nanoscale, hydrophobic channels that can be functionalized, making them artificial analogs for these biological channels. This project investigates the microscopic properties of water such as water density distributions and dynamics within CNTs using Nuclear Magnetic Resonance (NMR) and the structure of hydrated ions at CNT interfaces via X-ray Absorption Spectroscopy (XAS). Another component of this work is molecular simulation, which can predict experimental measurables such as the proton relaxation times, chemical shifts, and can compute the electronic structure of CNTs. Some of the fundamental questions this work is addressing are: (1) what is the length scale below which nanoscale effects such as molecular ordering become important, (2) is there a relationship between molecular ordering and transport?, and (3) how do ions interact with CNT interfaces? These are questions of interest to the scientific community, but they also impact the future generation of sensors, filters, and other devices that operate on the nanometer length scale. To enable some of the proposed applications of CNTs as ion filtration media and electrolytic supercapacitors, a detailed knowledge of water and ion structure at CNT interfaces is critical.

  9. Possible Diamond-Like Nanoscale Structures Induced by Slow Highly-Charged Ions on Graphite (HOPG)

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E.; Schenkel, T.; Shrivastava, S.; Makgato, T.; Batra, A.; Weis, C. D.; Persaud, A.; Erasmus, R.; Mwakikunga, B.

    2009-01-06

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosizeareas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  10. Numerical analysis of micro-/nanoscale gas-film lubrication of sliding surface with complicated structure

    International Nuclear Information System (INIS)

    Kawagoe, Yoshiaki; Isono, Susumu; Takeno, Takanori; Yonemura, Shigeru; Takagi, Toshiyuki; Miki, Hiroyuki

    2014-01-01

    It has been reported that the friction between a partially polished diamond-coated surface and a metal surface was drastically reduced to zero when they are slid at a few m/s. Since the sliding was noiseless, it seems that the diamond-coated surface was levitated over the counter surface and the sliding mechanism was the gas film lubrication. Recently, the mechanism of levitation of a slider with a micro/nanoscale surface structure on a rotating disk was theoretically clarified [S. Yonemura et al., Tribol. Lett., (2014), doi:10.1007/s11249-014-0368-2]. Probably, the partially polished diamond-coated surface may be levitated by high gas pressure generated by the micro/nanoscale surface structure on it. In this study, in order to verify our deduction, we performed numerical simulations of sliding of partially polished diamond-coated surface by reproducing its complicated surface structure using the data measured by an atomic force microscope (AFM). As a result, we obtained the lift force which is large enough to levitate the slider used in the experiment

  11. Numerical analysis of micro-/nanoscale gas-film lubrication of sliding surface with complicated structure

    Energy Technology Data Exchange (ETDEWEB)

    Kawagoe, Yoshiaki; Isono, Susumu; Takeno, Takanori [Department of Nanomechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yonemura, Shigeru; Takagi, Toshiyuki [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Miki, Hiroyuki [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578 (Japan)

    2014-12-09

    It has been reported that the friction between a partially polished diamond-coated surface and a metal surface was drastically reduced to zero when they are slid at a few m/s. Since the sliding was noiseless, it seems that the diamond-coated surface was levitated over the counter surface and the sliding mechanism was the gas film lubrication. Recently, the mechanism of levitation of a slider with a micro/nanoscale surface structure on a rotating disk was theoretically clarified [S. Yonemura et al., Tribol. Lett., (2014), doi:10.1007/s11249-014-0368-2]. Probably, the partially polished diamond-coated surface may be levitated by high gas pressure generated by the micro/nanoscale surface structure on it. In this study, in order to verify our deduction, we performed numerical simulations of sliding of partially polished diamond-coated surface by reproducing its complicated surface structure using the data measured by an atomic force microscope (AFM). As a result, we obtained the lift force which is large enough to levitate the slider used in the experiment.

  12. Nanoscale assembly of lanthanum silica with dense and porous interfacial structures.

    Science.gov (United States)

    Ballinger, Benjamin; Motuzas, Julius; Miller, Christopher R; Smart, Simon; Diniz da Costa, João C

    2015-02-03

    This work reports on the nanoscale assembly of hybrid lanthanum oxide and silica structures, which form patterns of interfacial dense and porous networks. It was found that increasing the molar ratio of lanthanum nitrate to tetraethyl orthosilicate (TEOS) in an acid catalysed sol-gel process alters the expected microporous metal oxide silica structure to a predominantly mesoporous structure above a critical lanthanum concentration. This change manifests itself by the formation of a lanthanum silicate phase, which results from the reaction of lanthanum oxide nanoparticles with the silica matrix. This process converts the microporous silica into the denser silicate phase. Above a lanthanum to silica ratio of 0.15, the combination of growth and microporous silica consumption results in the formation of nanoscale hybrid lanthanum oxides, with the inter-nano-domain spacing forming mesoporous volume. As the size of these nano-domains increases with concentration, so does the mesoporous volume. The absence of lanthanum hydroxide (La(OH)3) suggests the formation of La2O3 surrounded by lanthanum silicate.

  13. Assembly and structural analysis of a covalently closed nano-scale DNA cage

    DEFF Research Database (Denmark)

    Andersen, Félicie Faucon; Knudsen, Bjarne; Oliveira, Cristiano Luis Pinto De

    2008-01-01

    for investigations of DNA-interacting enzymes. More recently, strategies for synthesis of more complex two-dimensional (2D) and 3D DNA structures have emerged. However, the building of such structures is still in progress and more experiences from different research groups and different fields of expertise...... be described as a nano-scale DNA cage, Hence, in theory it could hold proteins or other bio-molecules to enable their investigation in certain harmful environments or even allow their organization into higher order structures...... The inherent properties of DNA as a stable polymer with unique affinity for partner molecules determined by the specific Watson-Crick base pairing makes it an ideal component in self-assembling structures. This has been exploited for decades in the design of a variety of artificial substrates...

  14. An assessment of the contributing factors to the nanoscale structural refinement of advanced bainitic steels

    International Nuclear Information System (INIS)

    Cornide, J.; Garcia-Mateo, C.; Capdevila, C.; Caballero, F.G.

    2013-01-01

    A new generation of steels has been designed, which on transformation at low temperature (200–350 °C), leads to a nano-scale microstructure, known as NANOBAIN. The microstructure consists of slender crystals of ferrite, whose controlling scale compares well with that of carbon nanotubes (20–40 nm). These advanced steels present the highest strength/toughness combinations ever recorded in bainitic steels. Their properties are mainly a consequence of the formation of nanoscale bainitic ferrite plates at very low temperatures. Transmission electron microscopy observations have shown that plastic relaxation in the austenite adjacent to the bainite plates may control the final size of the bainitic ferrite plates. The dislocation debris generated in this process resists the advance of the bainitic ferrite–austenite interface, the resistance being greatest for strong austenite. The yield strength of the austenite must then feature in any assessment of plate size. In this scenario, the plates are expected to become thicker at high temperatures because the yield strength of the austenite will then be lower. The goal of this study is to evaluate the influence of yield strength of austenite to the nanoscale structural refinement of advanced bainitic steels. In this sense, in situ measurements of austenite strength before bainite formation using a deformation dilatometer Bähr 805D have been performed in a medium carbon high silicon steel transforming at intermediate temperatures (325–400 °C) to a submicron structure of bainite and in a high carbon high silicon steel transforming at low temperatures (200–350 °C) to nanostructured bainite. The role of the transformation driving force on the bainite plate thickness will be also discussed

  15. An assessment of the contributing factors to the nanoscale structural refinement of advanced bainitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Cornide, J., E-mail: jca@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain); Garcia-Mateo, C., E-mail: cgm@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain); Capdevila, C., E-mail: ccm@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain); Caballero, F.G., E-mail: fgc@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040 (Spain)

    2013-11-15

    A new generation of steels has been designed, which on transformation at low temperature (200–350 °C), leads to a nano-scale microstructure, known as NANOBAIN. The microstructure consists of slender crystals of ferrite, whose controlling scale compares well with that of carbon nanotubes (20–40 nm). These advanced steels present the highest strength/toughness combinations ever recorded in bainitic steels. Their properties are mainly a consequence of the formation of nanoscale bainitic ferrite plates at very low temperatures. Transmission electron microscopy observations have shown that plastic relaxation in the austenite adjacent to the bainite plates may control the final size of the bainitic ferrite plates. The dislocation debris generated in this process resists the advance of the bainitic ferrite–austenite interface, the resistance being greatest for strong austenite. The yield strength of the austenite must then feature in any assessment of plate size. In this scenario, the plates are expected to become thicker at high temperatures because the yield strength of the austenite will then be lower. The goal of this study is to evaluate the influence of yield strength of austenite to the nanoscale structural refinement of advanced bainitic steels. In this sense, in situ measurements of austenite strength before bainite formation using a deformation dilatometer Bähr 805D have been performed in a medium carbon high silicon steel transforming at intermediate temperatures (325–400 °C) to a submicron structure of bainite and in a high carbon high silicon steel transforming at low temperatures (200–350 °C) to nanostructured bainite. The role of the transformation driving force on the bainite plate thickness will be also discussed.

  16. Nanoscale Structural and Mechanical Analysis of Bacillus anthracis Spores Inactivated with Rapid Dry Heating

    Science.gov (United States)

    Felker, Daniel L.; Burggraf, Larry W.

    2014-01-01

    Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142

  17. The Effect of the Nanoscale Structure of Nanobioceramics on Their In Vitro Bioactivity and Cell Differentiation Properties

    Directory of Open Access Journals (Sweden)

    Cristian Covarrubias

    2015-01-01

    Full Text Available The effect of the nanoscale structure of bioceramics on their in vitro bioactivity and capacity to osteogenically differentiate stem cell is studied. Nanoparticles of hydroxyapatite (nHA, bioactive glass (nBG, nanoporous bioactive glass (MBG, and nanoporous bioactive glass nanospheres (nMBG are investigated. The nanometric particle size of bioceramics seems to be more determining in controlling the ability to induce bone-like apatite as compared to the nanoporous structure. At short incubation time, nBG also produces a bioactive extracellular medium capable of upregulating key osteogenic markers involved in the development of a mineralizing phenotype in DPSCs. The bioactive properties of nBG are promissory for accelerating the bone regeneration process in tissue engineering applications.

  18. Partial wave spectroscopy based nanoscale structural disorder analysis for cancer diagnosis and treatment

    Science.gov (United States)

    Almabadi, Huda; Sahay, Peeyush; Nagesh, Prashanth K. B.; Yallapu, Murali M.; Jaggi, Meena; Chauhan, Subhash C.; Pradhan, Prabhakar

    Mesoscopic physics based partial wave spectroscopy (PWS) was recently introduced to quantify nanoscale structural disorder in weakly disordered optical media such as biological cells. The degree of structural disorder (Ld) , defined as Ld = 〈 dn2 〉 ×lc is quantified in terms of strength of refractive index fluctuation (〈 dn2 〉) in the system and its correlation length (lc) .With nanoscale sensitivity,Ldhas been shown to have potential to be used in cancer diagnostics. In this work, we analyze the hierarchy of different stages of prostate cancer cells by quantifying their intracellular refractive index fluctuations in terms of Ld parameter. We observe that the increase in tumorigenicity levels inside these prostate cancer cells results in proportionally higherLdvalues. For a weakly disordered optical media like biological cells, this result suggests that the progression of carcinogenesis or the increase in the tumorigenicity level is associated with increased 〈 dn2 〉 and/or lcvalues for the samples. Furthermore, we also examined the applicability of Ld parameter in analyzing the effect of drug on these prostate cancer cells. In accordance with the hypothesis that the cancer cells which survives the drug, becomes more aggressive, we found increased Ldvalues for all the drug resistant prostate cells studied.

  19. Probing Structural and Catalytic Characteristics of Galactose Oxidase Confined in Nanoscale Chemical Environments

    DEFF Research Database (Denmark)

    Ikemoto, Hideki; Mossin, Susanne; Ulstrup, Jens

    2014-01-01

    Galactose oxidase (GAOX) is a special metalloenzyme in terms of its active site structure and catalytic mechanisms. This work reports a study where the enzyme confined in a nanoscale chemical environment provided by mesoporous silicas (MPS) is probed. Two types of MPS, i.e. SBA-15 and MCF, were...... synthesized and used to accommodate GAOX. SBA-15-ROD is rod-shaped particles with periodically ordered nanopores (9.5 nm), while MCF has a mesocellular foam-like structure with randomly distributed pores (23 nm) interconnected by smaller windows (8.8 nm). GAOX is non-covalently confined in SBA-15- ROD, while...... it is covalently immobilized in MCF. Relatively high loadings in the range of 50–60 mg g1 are achieved. Electron spin resonance (ESR) spectroscopy is used to probe the active site structures of the enzyme. The similar ESR spectra observed for GAOX in the free and immobilized states support that the electronic...

  20. NASA GSFC Strategic Nanotechnology Interests: Symposium on High-Rate Nanoscale Printing for Devices and Structures

    Science.gov (United States)

    Ericsson, Aprille J.

    2014-01-01

    The seminars invitees include representatives from industry, nonprofit research facility and universities. The presentation provides an overview of the NASAGSFC locations, technical capabilities and applied nanotechnology interests. Initially presented are advances by the broader technological communities on current miniaturized multiscale advanced manufacturing and 3D printing products on the micro and macro scale. Briefly assessed is the potential of moving toward the nanoscale for possible space flight applications and challenges. Lastly, highlighted are GSFCs current successes in nano-technology developments and targeted future applications.

  1. Development of sustainable paper coatings using nanoscale industrial surface processing

    DEFF Research Database (Denmark)

    Markert, Frank; Breedveld, Leo; Lahti, Johanna

    in the PlasmaNice project, as environmental and social aspects are addressed using methods like life cycle check (LCC), life cycle assessment (LCA), and industrial risk assessment (RA) within the boundary of an economical production for different market segments. The results are intended to be used partly...... products, and the process and material developers providing new coatings with specific properties. The combination of RA and LCA/LCC within the early stages of product development provide a more holistic approach, It is commonly believed to be also economical beneficial as changes are easier to implement...

  2. Shell and membrane theories in mechanics and biology from macro- to nanoscale structures

    CERN Document Server

    Mikhasev, Gennadi

    2015-01-01

    This book presents the latest results related to shells  characterize and design shells, plates, membranes and other thin-walled structures, a multidisciplinary approach from macro- to nanoscale is required which involves the classical disciplines of mechanical/civil/materials engineering (design, analysis, and properties) and physics/biology/medicine among others. The book contains contributions of a meeting of specialists (mechanical engineers, mathematicians, physicists and others) in such areas as classical and non-classical shell theories. New trends with respect to applications in mechanical, civil and aero-space engineering, as well as in new branches like medicine and biology are presented which demand improvements of the theoretical foundations of these theories and a deeper understanding of the material behavior used in such structures.

  3. Electron Microscopy and Analytical X-ray Characterization of Compositional and Nanoscale Structural Changes in Fossil Bone

    Science.gov (United States)

    Boatman, Elizabeth Marie

    The nanoscale structure of compact bone contains several features that are direct indicators of bulk tissue mechanical properties. Fossil bone tissues represent unique opportunities to understand the compact bone structure/property relationships from a deep time perspective, offering a possible array of new insights into bone diseases, biomimicry of composite materials, and basic knowledge of bioapatite composition and nanoscale bone structure. To date, most work with fossil bone has employed microscale techniques and has counter-indicated the survival of bioapatite and other nanoscale structural features. The obvious disconnect between the use of microscale techniques and the discernment of nanoscale structure has prompted this work. The goal of this study was to characterize the nanoscale constituents of fossil compact bone by applying a suite of diffraction, microscopy, and spectrometry techniques, representing the highest levels of spatial and energy resolution available today, and capable of complementary structural and compositional characterization from the micro- to the nanoscale. Fossil dinosaur and crocodile long bone specimens, as well as modern ratite and crocodile femurs, were acquired from the UC Museum of Paleontology. Preserved physiological features of significance were documented with scanning electron microscopy back-scattered imaging. Electron microprobe wavelength-dispersive X-ray spectroscopy (WDS) revealed fossil bone compositions enriched in fluorine with a complementary loss of oxygen. X-ray diffraction analyses demonstrated that all specimens were composed of apatite. Transmission electron microscopy (TEM) imaging revealed preserved nanocrystallinity in the fossil bones and electron diffraction studies further identified these nanocrystallites as apatite. Tomographic analyses of nanoscale elements imaged by TEM and small angle X-ray scattering were performed, with the results of each analysis further indicating that nanoscale structure is

  4. Fabrication of two-dimensional visible wavelength nanoscale plasmonic structures using hydrogen silsesquioxane based resist

    Science.gov (United States)

    Smith, Kyle Z.; Gadde, Akshitha; Kadiyala, Anand; Dawson, Jeremy M.

    2016-03-01

    In recent years, the global market for biosensors has continued to increase in combination with their expanding use in areas such as biodefense/detection, home diagnostics, biometric identification, etc. A constant necessity for inexpensive, portable bio-sensing methods, while still remaining simple to understand and operate, is the motivation behind novel concepts and designs. Labeled visible spectrum bio-sensing systems provide instant feedback that is both simple and easy to work with, but are limited by the light intensity thresholds required by the imaging systems. In comparison, label-free bio-sensing systems and other detection modalities like electrochemical, frequency resonance, thermal change, etc., can require additional technical processing steps to convey the final result, increasing the system's complexity and possibly the time required for analysis. Further decrease in the detection limit can be achieved through the addition of plasmonic structures into labeled bio-sensing systems. Nano-structures that operate in the visible spectrum have feature sizes typically in the order of the operating wavelength, calling for high aspect ratio nanoscale fabrication capabilities. In order to achieve these dimensions, electron beam lithography (EBL) is used due to its accurate feature production. Hydrogen silsesquioxane (HSQ) based electron beam resist is chosen for one of its benefits, which is after exposure to oxygen plasma, the patterned resist cures into silicon dioxide (SiO2). These cured features in conjunction with nanoscale gold particles help in producing a high electric field through dipole generation. In this work, a detailed process flow of the fabrication of square lattice of plasmonic structures comprising of gold coated silicon dioxide pillars designed to operate at 560 nm wavelength and produce an intensity increase of roughly 100 percent will be presented.

  5. Broadband photosensor with a tunable frequency range, built on the basis of nanoscale carbon structure with field localization

    Science.gov (United States)

    Yakunin, Alexander N.; Akchurin, Garif G.; Aban'shin, Nikolay P.; Gorfinkel, Boris I.

    2014-03-01

    The work is devoted to the development of a new direction in creating of broadband photo sensors which distinctive feature is the possibility of dynamic adjustment of operating frequency range. The author's results of study of red threshold control of classic photoelectric effect were the basis for the work implementation. This effect was predicted theoretically and observed experimentally during irradiation of nanoscale carbon structure of planar-edge type by stream of low-energy photons. The variation of the accelerating voltage within a small range allows you to change photoelectric threshold for carbon in a wide range - from UV to IR. This is the consequence of the localization of electrostatic field at tip of the blade planar structure and of changes in the conditions of non-equilibrium electrons tunneling from the boundary surface of the cathode into the vacuum. The generation of nonequilibrium electrons in the carbon film thickness of 20 nm has a high speed which provides high performance of photodetector. The features of the use of nanoscale carbon structure photocurrent registration as in the prethreshold regime, and in the mode of field emission existence are discussed. The results of simulation and experimental examination of photosensor samples are given. It is shown that the observed effect is a single-photon tunneling. This in combination with the possibility of highspeed dynamic tuning determines the good perspectives for creation of new devices working in the mode of select multiple operating spectral bands for the signal recording. The architecture of such devices is expected to be significantly simpler than the conventional ones, based on the use of tunable filters.

  6. Nano-scale patterns of polymers and their structural phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Yushu [Tokyo Univ. (Japan). Inst. for Solid State Physics

    1998-03-01

    Nano-scale patterns formed by polymers and their related soft materials were investigated by measuring neutron scattering from them. Two apparatuses installed at cold neutron guides in JRR-3M, a small angle neutron scattering (SANS) apparatus and a neutron reflectometer, which give out elastic scattering intensities, were used. Chain dimensions of polystyrenes diluted with low molecular weight homologous polystyrenes, orientation behaviour of microphase-separated block copolymer in concentrated solutions under shear, shrinkage and recovery of polyvinylalcohol gel with temperature and structural phase transition of microemulsion under high-pressure and so on were measured by SANS, while microphase-separated polystyrene(S)/poly(2-vinylpyridine)(P) interfaces of a PSP triblock copolymer was observed by specular neutron reflectivity measurements. (author)

  7. Dynamics at the nanoscale

    International Nuclear Information System (INIS)

    Stoneham, A.M.; Gavartin, J.L.

    2007-01-01

    However fascinating structures may be at the nanoscale, time-dependent behaviour at the nanoscale has far greater importance. Some of the dynamics is random, with fluctuations controlling rate processes and making thermal ratchets possible. Some of the dynamics causes the transfer of energy, of signals, or of charge. Such transfers are especially efficiently controlled in biological systems. Other dynamical processes occur when we wish to control the nanoscale, e.g., to avoid local failures of gate dielectrics, or to manipulate structures by electronic excitation, to use spin manipulation in quantum information processing. Our prime purpose is to make clear the enormous range and variety of time-dependent nanoscale phenomena

  8. Quantitative FLIM-FRET Microscopy to Monitor Nanoscale Chromatin Compaction In Vivo Reveals Structural Roles of Condensin Complexes

    Directory of Open Access Journals (Sweden)

    David Llères

    2017-02-01

    Full Text Available How metazoan genomes are structured at the nanoscale in living cells and tissues remains unknown. Here, we adapted a quantitative FRET (Förster resonance energy transfer-based fluorescence lifetime imaging microscopy (FLIM approach to assay nanoscale chromatin compaction in living organisms. Caenorhabditis elegans was chosen as a model system. By measuring FRET between histone-tagged fluorescent proteins, we visualized distinct chromosomal regions and quantified the different levels of nanoscale compaction in meiotic cells. Using RNAi and repetitive extrachromosomal array approaches, we defined the heterochromatin state and showed that its architecture presents a nanoscale-compacted organization controlled by Heterochromatin Protein-1 (HP1 and SETDB1 H3-lysine-9 methyltransferase homologs in vivo. Next, we functionally explored condensin complexes. We found that condensin I and condensin II are essential for heterochromatin compaction and that condensin I additionally controls lowly compacted regions. Our data show that, in living animals, nanoscale chromatin compaction is controlled not only by histone modifiers and readers but also by condensin complexes.

  9. Nanoscale characterization of martensite structures in copper based shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Adiguzel, O, E-mail: oadiguzel@firat.edu.t [Firat University Department of Physics, 23169 Elazig (Turkey)

    2010-11-01

    Martensitic transformations are first order displacive transitions and occur in the materials on cooling from high temperature. Shape memory effect is an unusual property exhibited by certain alloy systems, and leads to martensitic transition. Copper-based alloys exhibit this property in beta phase field which possess simple bcc- structures, austenite structure at high-temperatures. As temperature is lowered the austenite undergoes martensitic transition following two ordering reactions, and structural changes in nanoscale govern this transition. Atomic movements are also confined to interatomic lengths in sub-{mu}m or angstrom scale in martensitic transformation. The formation of the layered structures in copper based alloys consists of shears and shear mechanism. Martensitic transformations occur in a few steps with the cooperative movement of atoms less than interatomic distances by means of lattice invariant shears on a {l_brace}110{r_brace} - type plane of austenite matrix which is basal plane or stacking plane of martensite. The lattice invariant shears occurs, in two opposite directions, <110> -type directions on the {l_brace}110{r_brace}-type plane. These shears gives rise to the formation of layered structure.

  10. Real time nanoscale structural evaluation of gold structures on Si (100) surface using in-situ transmission electron microscopy

    International Nuclear Information System (INIS)

    Rath, A.; Juluri, R. R.; Satyam, P. V.

    2014-01-01

    Transport behavior of gold nanostructures on Si(100) substrate during annealing under high vacuum has been investigated using in-situ real time transmission electron microscopy (TEM). A comparative study has been done on the morphological changes due to annealing under different vacuum environments. Au thin films of thickness ∼2.0 nm were deposited on native oxide covered silicon substrate by using thermal evaporation system. In-situ real time TEM measurements at 850 °C showed the isotropic growth of rectangular/square shaped gold-silicon alloy structures. During the growth, it is observed that the alloying occurs in liquid phase followed by transformation into the rectangular shapes. For similar system, ex-situ annealing in low vacuum (10 −2 millibars) at 850 °C showed the spherical gold nanostructures with no Au-Si alloy formation. Under low vacuum annealing conditions, the rate of formation of the oxide layer dominates the oxide desorption rate, resulting in the creation of a barrier layer between Au and Si, which restricts the inter diffusion of Au in to Si. This work demonstrates the important role of interfacial oxide layer on the growth of nanoscale Au-Si alloy structures during the initial growth. The time dependent TEM images are presented to offer a direct insight into the fundamental dynamics of the sintering process at the nanoscale

  11. Nanoscale stiffness topography reveals structure and mechanics of the transport barrier in intact nuclear pore complexes

    Science.gov (United States)

    Bestembayeva, Aizhan; Kramer, Armin; Labokha, Aksana A.; Osmanović, Dino; Liashkovich, Ivan; Orlova, Elena V.; Ford, Ian J.; Charras, Guillaume; Fassati, Ariberto; Hoogenboom, Bart W.

    2015-01-01

    The nuclear pore complex (NPC) is the gate for transport between the cell nucleus and the cytoplasm. Small molecules cross the NPC by passive diffusion, but molecules larger than ∼5 nm must bind to nuclear transport receptors to overcome a selective barrier within the NPC. Although the structure and shape of the cytoplasmic ring of the NPC are relatively well characterized, the selective barrier is situated deep within the central channel of the NPC and depends critically on unstructured nuclear pore proteins, and is therefore not well understood. Here, we show that stiffness topography with sharp atomic force microscopy tips can generate nanoscale cross-sections of the NPC. The cross-sections reveal two distinct structures, a cytoplasmic ring and a central plug structure, which are consistent with the three-dimensional NPC structure derived from electron microscopy. The central plug persists after reactivation of the transport cycle and resultant cargo release, indicating that the plug is an intrinsic part of the NPC barrier. Added nuclear transport receptors accumulate on the intact transport barrier and lead to a homogenization of the barrier stiffness. The observed nanomechanical properties in the NPC indicate the presence of a cohesive barrier to transport and are quantitatively consistent with the presence of a central condensate of nuclear pore proteins in the NPC channel.

  12. Molecular Structure and Dynamics of Water on Pristine and Strained Phosphorene: Wetting and Diffusion at Nanoscale.

    Science.gov (United States)

    Zhang, Wei; Ye, Chao; Hong, Linbi; Yang, Zaixing; Zhou, Ruhong

    2016-12-06

    Phosphorene, a newly fabricated two-dimensional (2D) nanomaterial, has emerged as a promising material for biomedical applications with great potential. Nonetheless, understanding the wetting and diffusive properties of bio-fluids on phosphorene which are of fundamental importance to these applications remains elusive. In this work, using molecular dynamics (MD) simulations, we investigated the structural and dynamic properties of water on both pristine and strained phosphorene. Our simulations indicate that the diffusion of water molecules on the phosphorene surface is anisotropic, with strain-enhanced diffusion clearly present, which arises from strain-induced smoothing of the energy landscape. The contact angle of water droplet on phosphorene exhibits a non-monotonic variation with the transverse strain. The structure of water on transverse stretched phosphorene is demonstrated to be different from that on longitudinal stretched phosphorene. Moreover, the contact angle of water on strained phosphorene is proportional to the quotient of the longitudinal and transverse diffusion coefficients of the interfacial water. These findings thereby offer helpful insights into the mechanism of the wetting and transport of water at nanoscale, and provide a better foundation for future biomedical applications of phosphorene.

  13. Nanoscale Structure of Type I Collagen Fibrils: Quantitative Measurement of D-spacing

    Science.gov (United States)

    Erickson, Blake; Fang, Ming; Wallace, Joseph M.; Orr, Bradford G.; Les, Clifford M.; Holl, Mark M. Banaszak

    2012-01-01

    This paper details a quantitative method to measure the D-periodic spacing of Type I collagen fibrils using Atomic Force Microscopy coupled with analysis using a 2D Fast Fourier Transform approach. Instrument calibration, data sampling and data analysis are all discussed and comparisons of the data to the complementary methods of electron microscopy and X-ray scattering are made. Examples of the application of this new approach to the analysis of Type I collagen morphology in disease models of estrogen depletion and Osteogenesis Imperfecta are provided. We demonstrate that it is the D-spacing distribution, not the D-spacing mean, that showed statistically significant differences in estrogen depletion associated with early stage Osteoporosis and Osteogenesis Imperfecta. The ability to quantitatively characterize nanoscale morphological features of Type I collagen fibrils will provide important structural information regarding Type I collagen in many research areas, including tissue aging and disease, tissue engineering, and gene knock out studies. Furthermore, we also envision potential clinical applications including evaluation of tissue collagen integrity under the impact of diseases or drug treatments. PMID:23027700

  14. Nanoscale “Quantum” Islands on Metal Substrates: Microscopy Studies and Electronic Structure Analyses

    Directory of Open Access Journals (Sweden)

    Da-Jiang Liu

    2010-07-01

    Full Text Available Confinement of electrons can occur in metal islands or in continuous films grown heteroepitaxially upon a substrate of a different metal or on a metallic alloy. Associated quantum size effects (QSE can produce a significant height-dependence of the surface free energy for nanoscale thicknesses of up to 10–20 layers. This may suffice to induce height selection during film growth. Scanning STM analysis has revealed remarkable flat-topped or mesa-like island and film morphologies in various systems. We discuss in detail observations of QSE and associated film growth behavior for Pb/Cu(111, Ag/Fe(100, and Cu/fcc-Fe/Cu(100 [A/B or A/B/A], and for Ag/NiAl(110 with brief comments offered for Fe/Cu3Au(001 [A/BC binary alloys]. We also describe these issues for Ag/5-fold i-Al-Pd-Mn and Bi/5-fold i-Al-Cu-Fe [A/BCD ternary icosohedral quasicrystals]. Electronic structure theory analysis, either at the level of simple free electron gas models or more sophisticated Density Functional Theory calculations, can provide insight into the QSE-mediated thermodynamic driving force underlying height selection.

  15. Laboratory micro- and nanoscale X-ray tomographic investigation of Al–7 at.%Cu solidification structures

    International Nuclear Information System (INIS)

    Patterson, B.M.; Henderson, K.C.; Gibbs, P.J.; Imhoff, S.D.; Clarke, A.J.

    2014-01-01

    X-ray computed tomography across multiple length scales provides an opportunity to non-destructively visualize and quantify the micro- to nano-scale microstructural features of solidification structures in three dimensions. Aluminum–7 at.%copper samples were directionally solidified at three cooling rates (0.44, 0.67, and 1.33 °C/s), resulting in systematic changes in the as-solidified microstructure, which are difficult to quantify using traditional microscopic techniques. The cooling rate of a material affects its ultimate microstructure, and characterizing that microstructure is key to predicting and understanding its bulk properties. Here, two different laboratory X-ray computed tomography instruments were used to characterize as-solidified microstructures, including micro-scale computed tomography with approximately 1 mm field-of-view, ∼ 1.7 μm resolution, and nano-scale X-ray computed tomography ∼ 65 μm FOV, 150 nm resolution. Micro-scale X-ray radiography and computed tomography enabled a quantitative investigation of changes in the primary dendritic solidification structure with increasing cooling rate. Nano-scale absorption contrast X-ray computed tomography resolved the distinct phases of the lamellar eutectic structure and three dimensional measurements of the ∼ 1 μm interlamellar spacing. It is found that the lamella eutectic structure thickness is inversely proportional to the cooling rate. Nano-scale Zernike phase contrast was also used to image voids at eutectic colony boundaries. The application and resolution of these two instruments are discussed with respect to the resolvable features of the solidification structures. - Highlights: • Al–Cu eutectic is a model system for studying solidification microstructure. • X-ray computed tomography provides a 3D picture of these complex structures. • Micro-scale tomography images the primary and secondary dendritic structures. • Nano-scale tomography images the eutectic lamella and

  16. Laboratory micro- and nanoscale X-ray tomographic investigation of Al–7 at.%Cu solidification structures

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, B.M., E-mail: bpatterson@lanl.gov; Henderson, K.C.; Gibbs, P.J.; Imhoff, S.D.; Clarke, A.J.

    2014-09-15

    X-ray computed tomography across multiple length scales provides an opportunity to non-destructively visualize and quantify the micro- to nano-scale microstructural features of solidification structures in three dimensions. Aluminum–7 at.%copper samples were directionally solidified at three cooling rates (0.44, 0.67, and 1.33 °C/s), resulting in systematic changes in the as-solidified microstructure, which are difficult to quantify using traditional microscopic techniques. The cooling rate of a material affects its ultimate microstructure, and characterizing that microstructure is key to predicting and understanding its bulk properties. Here, two different laboratory X-ray computed tomography instruments were used to characterize as-solidified microstructures, including micro-scale computed tomography with approximately 1 mm field-of-view, ∼ 1.7 μm resolution, and nano-scale X-ray computed tomography ∼ 65 μm FOV, 150 nm resolution. Micro-scale X-ray radiography and computed tomography enabled a quantitative investigation of changes in the primary dendritic solidification structure with increasing cooling rate. Nano-scale absorption contrast X-ray computed tomography resolved the distinct phases of the lamellar eutectic structure and three dimensional measurements of the ∼ 1 μm interlamellar spacing. It is found that the lamella eutectic structure thickness is inversely proportional to the cooling rate. Nano-scale Zernike phase contrast was also used to image voids at eutectic colony boundaries. The application and resolution of these two instruments are discussed with respect to the resolvable features of the solidification structures. - Highlights: • Al–Cu eutectic is a model system for studying solidification microstructure. • X-ray computed tomography provides a 3D picture of these complex structures. • Micro-scale tomography images the primary and secondary dendritic structures. • Nano-scale tomography images the eutectic lamella and

  17. Oxide films at the nanoscale: new structures, new functions, and new materials.

    Science.gov (United States)

    Giordano, Livia; Pacchioni, Gianfranco

    2011-11-15

    We all make use of oxide ultrathin films, even if we are unaware of doing so. They are essential components of many common devices, such as mobile phones and laptops. The films in these ubiquitous electronics are composed of silicon dioxide, an unsurpassed material in the design of transistors. But oxide films at the nanoscale (typically just 10 nm or less in thickness) are integral to many other applications. In some cases, they form under normal reactive conditions and confer new properties to a material: one example is the corrosion protection of stainless steel, which is the result of a passive film. A new generation of devices for energy production and communications technology, such as ferroelectric ultrathin film capacitors, tunneling magnetoresistance sensors, solar energy materials, solid oxide fuel cells, and many others, are being specifically designed to exploit the unusual properties afforded by reduced oxide thickness. Oxide ultrathin films also have tremendous potential in chemistry, representing a rich new source of catalytic materials. About 20 years ago, researchers began to prepare model systems of truly heterogeneous catalysts based on thin oxide layers grown on single crystals of metal. Only recently, however, was it realized that these systems may behave quite differently from their corresponding bulk oxides. One of the phenomena uncovered is the occurrence of a spontaneous charge transfer from the metal support to an adsorbed species through the thin insulating layer (or vice versa). The importance of this property is clear: conceptually, the activation and bond breaking of adsorbed molecules begin with precisely the same process, electron transfer into an antibonding orbital. But electron transfer can also be harnessed to make a supported metal particle more chemically active, increase its adhesion energy, or change its shape. Most importantly, the basic principles underlying electron transfer and other phenomena (such as structural

  18. Nanoscale thermal transport

    Science.gov (United States)

    Cahill, David G.; Ford, Wayne K.; Goodson, Kenneth E.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Merlin, Roberto; Phillpot, Simon R.

    2003-01-01

    Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid-solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The

  19. Development of Self-Assembled Nanoscale Templates via Microphase Separation Induced by Polymer Brushes

    Science.gov (United States)

    Chu, Elza

    Phase separation in soft matter has been the crucial element in generating hybrid materials, such as polymer blends and mixed polymer brushes. This dissertation discusses two methods of developing self-assembled nanoscale templates via microphase separation induced by polymer brush synthesis. This work introduces a novel soft substrate approach with renewable grafting sites where polyacrylamide is "grafted through" chitosan soft substrates. The mechanism of grafting leads to ordered arrays of filament-like nanostructures spanning the chitosan-air interface. Additionally, the chemical composition of the filaments allows for post-chemical modification to change the physical properties of the filaments, and subsequently tailor surfaces for specific application. Unlike traditional materials, multi-functional or "smart" materials, such as binary polymer brushes (BPB) are capable of spontaneously changing the spatial distribution of functional groups and morphology at the surface upon external stimuli. Although promising in principle, the limited range of available complementary polymers with common non-selective solvents confines the diversity of usable materials and restricts any further advancement in the field. This dissertation also covers the fabrication and characterization of responsive nanoscale polystyrene templates or "mosaic" brushes that are capable of changing interfacial composition upon exposure to varying solvent qualities. Using a "mosaic" brush template is a unique approach that allows the fabrication of strongly immiscible polymer BPB without the need for a common solvent. The synthesis of such BPB is exemplified by two strongly immiscible polymers, i.e. polystyrene (polar) and polyacrylamide (non-polar), where polyacrylamide brush is "graft through" a Si-substrate modified with the polystyrene collapsed "mosaic" brush. The surface exhibits solvent-triggered responses, as well as application potential for anti-biofouling.

  20. Grazing incidence x-ray diffraction at free-standing nanoscale islands: fine structure of diffuse scattering

    International Nuclear Information System (INIS)

    Grigoriev, D; Hanke, M; Schmidbauer, M; Schaefer, P; Konovalov, O; Koehler, R

    2003-01-01

    We have investigated the x-ray intensity distribution around 220 reciprocal lattice point in case of grazing incidence diffraction at SiGe nanoscale free-standing islands grown on Si(001) substrate by LPE. Experiments and computer simulations based on the distorted wave Born approximation utilizing the results of elasticity theory obtained by FEM modelling have been carried out. The data reveal fine structure in the distribution of scattered radiation with well-pronounced maxima and complicated fringe pattern. Explanation of the observed diffraction phenomena in their relation to structure and morphology of the island is given. An optimal island model including its shape, size and Ge spatial distribution was elaborated

  1. Microscale and nanoscale hierarchical structured mesh films with superhydrophobic and superoleophilic properties induced by long-chain fatty acids

    International Nuclear Information System (INIS)

    Wang Shutao; Song Yanlin; Jiang Lei

    2007-01-01

    Inspired by the lotus effect, we fabricate new microscale and nanoscale hierarchical structured copper mesh films by a simple electrochemical deposition. After modification of the long-chain fatty acid monolayer, these films show superhydrophobic and superoleophilic properties, which could be used for the effective separation of oil and water. The length of the fatty acid chain strongly influences the surface wettability of as-prepared films. It is confirmed that the cooperative effect of the hierarchical structure of the copper film and the nature of the long-chain fatty acid contribute to this unique surface wettability

  2. Structure and composition of magnetocaloric Ni-Mn-In-Co thin films on the nanoscale - a TEM study

    Energy Technology Data Exchange (ETDEWEB)

    Erkartal, Burak; Schuermann, Ulrich; Kienle, Lorenz [Institute for Materials Science, Synthesis and Real Structure, Christian Albrechts University, Kiel (Germany); Duppel, Viola [Nanochemistry Max Planck Institute for Solid State Research, Stuttgart (Germany); Niemann, Robert; Schultz, Ludwig; Faehler, Sebastian [IFW Dresden (Germany)

    2012-08-15

    A complementary set of electron microscopy techniques is applied for the determination of structural and chemical segregation phenomena within a 300 nm thick metamagnetic Ni-Mn-In-Co thin film. The structure is predominantly composed of distinct modulated martensites of the 5M-, 6M-, 7M-, and 8M-type. Additionally these modulated structures exhibit twinning and stacking disordering. The nature of the disordering and the structural misfit at the twin interface were analyzed via high resolution micrographs. Next to an adhesion layer of Cr interdiffusion on the nanoscale was observed producing a penternary chemically and structurally homogeneous precipitate. The structure can be assigned to a twinned non-modulated pseudocubic model. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Probing and tuning the size, morphology, chemistry and structure of nanoscale cerium oxide

    Science.gov (United States)

    Kuchibhatla, Satyanarayana Vnt

    Cerium oxide (ceria)-based materials in the nanoscale regime are of significant fundamental and technological interest. Nanoceria in pure and doped forms has current and potential use in solid oxide fuel cells, catalysis, UV-screening, chemical mechanical planarization, oxygen sensors, and bio-medical applications. The characteristic feature of Ce to switch between the +3 and +4 oxidation states renders oxygen buffering capability to ceria. The ease of this transformation was expected to be enhanced in the nanoceria. In most the practical scenarios, it is necessary to have a stable suspension of ceria nanoparticles (CNPs) over longer periods of time. However, the existing literature is confined to short term studies pertaining to synthesis and property evaluation. Having understood the need for a comprehensive understanding of the CNP suspensions, this dissertation is primarily aimed at understanding the behavior of CNPs in various chemical and physical environments. We have synthesized CNPs in the absence of any surfactants at room temperature and studied the aging characteristics. After gaining some understanding about the behavior of this functional oxide, the synthesis environment and aging temperature were varied, and their affects were carefully analyzed using various materials analysis techniques such as high resolution transmission electron microscopy (HRTEM), UV-Visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS). When the CNPs were aged at room temperature in as-synthesized condition, they were observed to spontaneously assemble and evolve as fractal superoctahedral structures. The reasons for this unique polycrystalline morphology were attributed to the symmetry driven assembly of the individual truncated octahedral and octahedral seed of the ceria. HRTEM and Fast Fourier Transform (FFT) analyses were used to explain the agglomeration behavior and evolution of the octahedral morphology. Some of the observations were supported by

  4. Analysis of the nano-scale structure of a natural clayey soil using the small angle neutron scattering method

    International Nuclear Information System (INIS)

    Itakura, T.; Bertram, W.K.; Hathaway, P.V.; Knott, R.B.

    2001-01-01

    The small angle neutron scattering method (SANS) was used to analyze the nano-structure of a natural clayey soil used for containment of industrial liquid wastes. A Tertiary clay deposit called the Londonderry clay was used to contain the wastes in a state-run landfill facility in NSW. A number of site assessments have been carried out at the site and continual efforts have been made to characterize interactions between soil materials and contaminants at the site. Hence, it is of research and practical interest to investigate the effects of deformation on the nano-scale structure of the soil. Experiments have been conducted to analyze the structure of reconstituted clayey soil samples that were subjected to uniaxial compression ranging from 200 kPa to 800 kPa. The small angle neutron scattering instrument was used to measure the scattering intensity of these samples at a scattering vector (q) range between 0.01 and 0.1 Angstroms -1 . The sector integration technique was used to analyse elliptical scattering patterns along the major and minor axes. A relation between stress, void ratio and nano-scale structure properties was then briefly discussed for use in assessing the performance of clayey soils as in situ barriers

  5. An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

    KAUST Repository

    Sibillano, T.; De Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, Luca; Di Fabrizio, Enzo M.; Giannini, C.

    2014-01-01

    The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

  6. An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

    KAUST Repository

    Sibillano, T.

    2014-11-10

    The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes\\' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

  7. An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

    Science.gov (United States)

    Sibillano, T.; de Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, L.; di Fabrizio, E.; Giannini, C.

    2014-11-01

    The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

  8. Evaporation characteristics of a hydrophilic surface with micro-scale and/or nano-scale structures fabricated by sandblasting and aluminum anodization

    International Nuclear Information System (INIS)

    Kim, Hyungmo; Kim, Joonwon

    2010-01-01

    This paper presents the results of evaporation experiments using water droplets on aluminum sheets that were either smooth or had surface structures at the micro-scale, at the nano-scale or at both micro- and nano-scales (dual-scale). The smooth surface was a polished aluminum sheet; the surface with micro-scale structures was obtained by sandblasting; the surface with nano-scale structures was obtained using conventional aluminum anodization and the surface with dual-scale structures was prepared using sandblasting and anodization sequentially. The wetting properties and evaporation rates were measured for each surface. The evaporation rates were affected by their static and dynamic wetting properties. Evaporation on the surface with dual-scale structures was fastest and the evaporation rate was analyzed quantitatively.

  9. Sub-nanoscale surface ruggedness provides a water-tight seal for exposed regions in soluble protein structure.

    Directory of Open Access Journals (Sweden)

    Erica Schulz

    2010-09-01

    Full Text Available Soluble proteins must maintain backbone hydrogen bonds (BHBs water-tight to ensure structural integrity. This protection is often achieved by burying the BHBs or wrapping them through intermolecular associations. On the other hand, water has low coordination resilience, with loss of hydrogen-bonding partnerships carrying significant thermodynamic cost. Thus, a core problem in structural biology is whether natural design actually exploits the water coordination stiffness to seal the backbone in regions that are exposed to the solvent. This work explores the molecular design features that make this type of seal operative, focusing on the side-chain arrangements that shield the protein backbone. We show that an efficient sealing is achieved by adapting the sub-nanoscale surface topography to the stringency of water coordination: an exposed BHB may be kept dry if the local concave curvature is small enough to impede formation of the coordination shell of a penetrating water molecule. Examination of an exhaustive database of uncomplexed proteins reveals that exposed BHBs invariably occur within such sub-nanoscale cavities in native folds, while this level of local ruggedness is absent in other regions. By contrast, BHB exposure in misfolded proteins occurs with larger local curvature promoting backbone hydration and consequently, structure disruption. These findings unravel physical constraints fitting a spatially dependent least-action for water coordination, introduce a molecular design concept, and herald the advent of water-tight peptide-based materials with sufficient backbone exposure to remain flexible.

  10. Interaction of Natural Organic Matter with Layered Minerals: Recent Developments in Computational Methods at the Nanoscale

    Directory of Open Access Journals (Sweden)

    Jeffery A. Greathouse

    2014-06-01

    Full Text Available The role of mineral surfaces in the adsorption, transport, formation, and degradation of natural organic matter (NOM in the biosphere remains an active research area owing to the difficulties in identifying proper working models of both NOM and mineral phases present in the environment. The variety of aqueous chemistries encountered in the subsurface (e.g., oxic vs. anoxic, variable pH further complicate this field of study. Recently, the advent of nanoscale probes such as X-ray adsorption spectroscopy and surface vibrational spectroscopy applied to study such complicated interfacial systems have enabled new insight into NOM-mineral interfaces. Additionally, due to increasing capabilities in computational chemistry, it is now possible to simulate molecular processes of NOM at multiple scales, from quantum methods for electron transfer to classical methods for folding and adsorption of macroparticles. In this review, we present recent developments in interfacial properties of NOM adsorbed on mineral surfaces from a computational point of view that is informed by recent experiments.

  11. The Role of Isolation Methods on a Nanoscale Surface Structure and Its Effect on the Size of Exosomes

    Directory of Open Access Journals (Sweden)

    JungReem Woo

    2016-06-01

    Full Text Available Exosomes are ~100 nanometre diameter vesicles secreted by mammalian cells. These emerging disease biomarkers carry nucleic acids, proteins and lipids specific to the parental cells that secrete them. Exosomes are typically isolated in bulk by ultracentrifugation, filtration or immu‐ noaffinity precipitation for downstream proteomic, genomic, or lipidomic analysis. However, the structural properties and heterogeneity of isolated exosomes at the single vesicle level are not well characterized due to their small size. In this paper, by using high-resolution atomic force microscope imaging, we show the nanoscale mor‐ phology and structural heterogeneity in exosomes derived from U87 cells. Quantitative assessment of single exosomes reveals nanoscale variations in morphology, surface roughness and counts isolated by ultracentrifugation (UC and immunoaffinity (IA purification. Both methods produce intact globular, 30-120 nm sized vesicles when imaged under fluid and in air. However, IA exosomes had higher surface roughness and bimodal size population compared to UC exosomes. The study highlights the differences in size and surface topography of exosomes purified from a single cell type using different isolation methods.

  12. The growth of nanoscale ZnO films by pulsed-spray evaporation chemical vapor deposition and their structural, electric and optical properties

    International Nuclear Information System (INIS)

    Jiang Yinzhu; Bahlawane, Naoufal

    2010-01-01

    Great interest in nanoscale thin films (sub-100 nm) has been stimulated by the developing demands of functional devices. In this paper, nanoscale zinc oxide (ZnO) thin films were deposited on glass substrates at 300 o C by pulsed-spray evaporation chemical vapor deposition. Scanning electron micrographs indicate uniform surface morphologies composed of nanometer-sized spherical particles. The growth kinetics and growth mode are studied and the relationship between the film thickness and the electric properties with respect to the growth mode is interpreted. X-ray diffraction shows that all ZnO films grown by this process were crystallized in a hexagonal structure and highly oriented with their c-axes perpendicular to the plane of the substrate. Optical measurements show transparencies above 85% in the visible spectral range for all films. The absorbance in the UV spectral range respects well the Beer-Lambert law, enabling an accurate optical thickness measurement, and the absorption coefficient was measured for a selected wavelength. The measured band gap energies exhibit an almost constant value of 3.41 eV for all films with different thicknesses, which attributed to the thickness-independent crystallite size.

  13. Structurally Stable Attractive Nanoscale Emulsions with Dipole-Dipole Interaction-Driven Interdrop Percolation.

    Science.gov (United States)

    Shin, Kyounghee; Gong, Gyeonghyeon; Cuadrado, Jonas; Jeon, Serim; Seo, Mintae; Choi, Hong Sung; Hwang, Jae Sung; Lee, Youngbok; Fernandez-Nieves, Alberto; Kim, Jin Woong

    2017-03-28

    This study introduces an extremely stable attractive nanoscale emulsion fluid, in which the amphiphilic block copolymer, poly(ethylene oxide)-block-poly(ϵ-caprolactone) (PEO-b-PCL), is tightly packed with lecithin, thereby forming a mechanically robust thin-film at the oil-water interface. The molecular association of PEO-b-PCL with lecithin is critical for formation of a tighter and denser molecular assembly at the interface, which is systematically confirmed by T 2 relaxation and DSC analyses. Moreover, suspension rheology studies also reflect the interdroplet attractions over a wide volume fraction range of the dispersed oil phase; this results in a percolated network of stable drops that exhibit no signs of coalescence or phase separation. This unique rheological behavior is attributed to the dipolar interaction between the phosphorylcholine groups of lecithin and the methoxy end groups of PEO-b-PCL. Finally, the nanoemulsion system significantly enhances transdermal delivery efficiency due to its favorable attraction to the skin, as well as high diffusivity of the nanoscale emulsion drops. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Identification of nanoscale structure and morphology reconstruction in oxidized a-SiC:H thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vasin, A.V.; Rusavsky, A.V.; Nazarov, A.N.; Lysenko, V.S.; Lytvyn, P.M.; Strelchuk, V.V. [Lashkaryov Institute of Semiconductor Physics, 41 Nauki Pr., Kiev 03028 (Ukraine); Kholostov, K.I.; Bondarenko, V.P. [Belarusian State University of Informatics and Radioelectronics, 6P. Brovki Str., Minsk 220013 (Belarus); Starik, S.P. [Bakul Institute of Superhard Materials, 2 Avtzavodskaya Str., Kiev 04074 (Ukraine)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer Increase of magnetron discharge power results in densification of a-SiC:H thin films. Black-Right-Pointing-Pointer The denser a-SiC:H material the better resistance to oxidation by oxygen. Black-Right-Pointing-Pointer Oxidation of soft a-SiC:H films can result in increase of electric conductivity. Black-Right-Pointing-Pointer Formation of graphitic clusters was found in a-SiC:H after annealing in oxygen. - Abstract: Oxidation behavior of a-SiC:H layers deposited by radio-frequency magnetron sputtering technique was examined by Kelvin probe force microscopy (KPFM) in combination with scanning electron microscopy, Fourier-transform infra-red spectroscopy and submicron selected area Raman scattering spectroscopy. Partially oxidized a-SiC:H samples (oxidation at 600 Degree-Sign C in oxygen) were examined to clarify mechanism of the oxidation process. Nanoscale and microscale morphological defects (pits) with dimension of about 50 nm and several microns respectively have appeared after thermal treatment. KPFM measurements exhibited the surface potential of the material in micro pits is significantly smaller in comparison with surrounding material. Submicron RS measurements indicates formation of graphite-like nano-inclusions in the pit defects. We conclude that initial stage of oxidation process in a-SiC:H films takes place not homogeneously throughout the layer but it is initiated in local nanoscale regions followed by spreading over all layer.

  15. Quantitative analysis of nanoscale intranuclear structural alterations in hippocampal cells in chronic alcoholism via transmission electron microscopy imaging.

    Science.gov (United States)

    Sahay, Peeyush; Shukla, Pradeep K; Ghimire, Hemendra M; Almabadi, Huda M; Tripathi, Vibha; Mohanty, Samarendra K; Rao, Radhakrishna; Pradhan, Prabhakar

    2017-03-01

    Chronic alcoholism is known to alter the morphology of the hippocampus, an important region of cognitive function in the brain. Therefore, to understand the effect of chronic alcoholism on hippocampal neural cells, we employed a mouse model of chronic alcoholism and quantified intranuclear nanoscale structural alterations in these cells. Transmission electron microscopy (TEM) images of hippocampal neurons were obtained, and the degree of structural alteration in terms of mass density fluctuation was determined using the light-localization properties of optical media generated from TEM imaging. The results, which were obtained at length scales ranging from ~30 to 200 nm, show that 10-12 week-old mice fed a Lieber-DeCarli liquid (alcoholic) diet had a higher degree of structural alteration than control mice fed a normal diet without alcohol. The degree of structural alteration became significantly distinguishable at a sample length of ~100 nm, which is the typical length scale of the building blocks of cells, such as DNA, RNA, proteins and lipids. Interestingly, different degrees of structural alteration at such length scales suggest possible structural rearrangement of chromatin inside the nuclei in chronic alcoholism.

  16. Nanoscale Cu{sub 2}O films: Radio-frequency magnetron sputtering and structural and optical studies

    Energy Technology Data Exchange (ETDEWEB)

    Kudryashov, D. A., E-mail: kudryashovda@apbau.ru; Gudovskikh, A. S. [Russian Academy of Sciences, St. Petersburg National Research Academic University — Nanotechnology Research and Education Center (Russian Federation); Babichev, A. V.; Filimonov, A. V. [Connector Optics LLC (Russian Federation); Mozharov, A. M. [Russian Academy of Sciences, St. Petersburg National Research Academic University — Nanotechnology Research and Education Center (Russian Federation); Agekyan, V. F.; Borisov, E. V.; Serov, A. Yu.; Filosofov, N. G. [St. Petersburg State University (Russian Federation)

    2017-01-15

    Nanoscale copper (I) oxide layers are formed by magnetron-assisted sputtering onto glassy and silicon substrates in an oxygen-free environment at room temperature, and the structural and optical properties of the layers are studied. It is shown that copper oxide formed on a silicon substrate exhibits a lower degree of disorder than that formed on a glassy substrate, which is supported by the observation of a higher intensity and a smaller half-width of reflections in the diffraction pattern. The highest intensity of reflections in the diffraction pattern is observed for Cu{sub 2}O films grown on silicon at a magnetron power of 150 W. The absorption and transmittance spectra of these Cu{sub 2}O films are in agreement with the well-known spectra of bulk crystals. In the Raman spectra of the films, phonons inherent in the crystal lattice of cubic Cu{sub 2}O crystals are identified.

  17. Nanoscale Structural/Chemical Characterization of Manganese Oxide Surface Layers and Nanoparticles, and the Associated Implications for Drinking Water

    Science.gov (United States)

    Michel Eduardo Vargas Vallejo

    Water treatment facilities commonly reduce soluble contaminants, such as soluble manganese (Mn2+), in water by oxidation and subsequent filtration. Previous studies have shown that conventional porous filter system removes Mn2+ from drinking water by developing Mn-oxides (MnO x(s)) bearing coating layers on the surface of filter media. Multiple models have been developed to explain this Mn2+ removal process and the formation mechanism of MnOx(s) coatings. Both, experimental and theoretical studies to date have been largely focused on the micrometer to millimeter scale range; whereas, coating layers are composed of nanoscale particles and films. Hence, understanding the nanoscale particle and film formation mechanisms is essential to comprehend the complexity of soluble contaminant removal processes. The primary objective of this study was to understand the initial MnOx(s) coating formation mechanisms and evaluate the influence of filter media characteristics on these processes. We pursued this objective by characterizing at the micro and nanoscale MnO x(s) coatings developed on different filter media by bench-scale column tests with simulating inorganic aqueous chemistry of a typical coagulation fresh water treatment plant, where free chlorine is present across filter bed. Analytical SEM and TEM, powder and synchrotron-based XRD, XPS, and ICPMS were used for characterization of coatings, filter media and water solution elemental chemistry. A secondary objective was to model how surface coating formation occurred and its correlation with experimentally observed physical characteristics. This modeling exercise indicates that surface roughness and morphology of filtering media are the major contributing factors in surface coating formation process. Contrary to previous models that assumed a uniform distribution and growth of surface coating, the experimental results showed that greater amounts of coating were developed in rougher areas. At the very early stage of

  18. Nanoscale Electrochemical Sensing and Processing in Microreactors

    NARCIS (Netherlands)

    Odijk, Mathieu; van den Berg, Albert

    2018-01-01

    In this review, we summarize recent advances in nanoscale electrochemistry, including the use of nanoparticles, carbon nanomaterials, and nanowires. Exciting developments are reported for nanoscale redox cycling devices, which can chemically amplify signal readout. We also discuss promising

  19. Direct nanoscale imaging of evolving electric field domains in quantum structures.

    Science.gov (United States)

    Dhar, Rudra Sankar; Razavipour, Seyed Ghasem; Dupont, Emmanuel; Xu, Chao; Laframboise, Sylvain; Wasilewski, Zbig; Hu, Qing; Ban, Dayan

    2014-11-28

    The external performance of quantum optoelectronic devices is governed by the spatial profiles of electrons and potentials within the active regions of these devices. For example, in quantum cascade lasers (QCLs), the electric field domain (EFD) hypothesis posits that the potential distribution might be simultaneously spatially nonuniform and temporally unstable. Unfortunately, there exists no prior means of probing the inner potential profile directly. Here we report the nanoscale measured electric potential distribution inside operating QCLs by using scanning voltage microscopy at a cryogenic temperature. We prove that, per the EFD hypothesis, the multi-quantum-well active region is indeed divided into multiple sections having distinctly different electric fields. The electric field across these serially-stacked quantum cascade modules does not continuously increase in proportion to gradual increases in the applied device bias, but rather hops between discrete values that are related to tunneling resonances. We also report the evolution of EFDs, finding that an incremental change in device bias leads to a hopping-style shift in the EFD boundary--the higher electric field domain expands at least one module each step at the expense of the lower field domain within the active region.

  20. Shear-stress-induced structural arrangement of water molecules in nanoscale Couette flow with slipping at wall boundary

    International Nuclear Information System (INIS)

    Lin, Jau-Wen

    2014-01-01

    This study investigated the structuring of water molecules in a nanoscale Couette flow with the upper plate subjected to lateral forces with various magnitudes and water slipping against a metal wall. It was found that when the upper plate is subjected to a force, the water body deforms into a parallelepiped. Water molecules in the channel are then gradually arranged into lattice positions, creating a layered structure. The structural arrangement of water molecules is caused by the water molecules accommodating themselves to the increase in energy under the application of a lateral force on the moving plate. The ordering arrangement of water molecules increases the rotational degree of freedom, allowing the molecules to increase their Coulomb potential energy through polar rotation that accounts for the energy input through the upper plate. With a force continuously applied to the upper plate, the water molecules in contact with the upper plate move forward until slip between the water and upper plate occurs. The relation between the structural arrangement of water molecules, slip at the wall, and the shear force is studied. The relation between the slip and the locking/unlocking of water molecules to metal atoms is also studied

  1. Atomic Resolution Imaging of Nanoscale Structural Ordering in a Complex Metal Oxide Catalyst

    KAUST Repository

    Zhu, Yihan; Wang, Qingxiao; Zhao, Lan; Teng, Baiyang; Lu, Weimin; Han, Yu

    2012-01-01

    The determination of the atomic structure of a functional material is crucial to understanding its "structure-to-property" relationship (e.g., the active sites in a catalyst), which is however challenging if the structure possesses complex

  2. Label-free colorimetric detection of mercury via Hg2+ ions-accelerated structural transformation of nanoscale metal-oxo clusters

    Science.gov (United States)

    Chen, Kun; She, Shan; Zhang, Jiangwei; Bayaguud, Aruuhan; Wei, Yongge

    2015-11-01

    Mercury and its compounds are known to be extremely toxic but widely distributed in environment. Although many works have been reported to efficiently detect mercury, development of simple and convenient sensors is still longed for quick analyzing mercury in water. In this work, a nanoscale metal-oxo cluster, (n-Bu4N)2[Mo5NaO13(OCH3)4(NO)], (MLPOM), organically-derivatized from monolacunary Lindqvist-type polyoxomolybdate, is found to specifically react with Hg2+ in methanol/water via structural transformation. The MLPOM methanol solution displays a color change from purple to brown within seconds after being mixed with an aqueous solution containing Hg2+. By comparing the structure of polyoxomolybdate before and after reaction, the color change is revealed to be the essentially structural transformation of MLPOM accelerated by Hg2+. Based on this discovery, MLPOM could be utilized as a colorimetric sensor to sense the existence of Hg2+, and a simple and label-free method is developed to selectively detect aqueous Hg2+. Furthermore, the colorimetric sensor has been applied to indicating mercury contamination in industrial sewage.

  3. Space Structure Development

    Science.gov (United States)

    Smith, Thomas

    2015-01-01

    The duration of my Summer 2015 Internship Tour at NASA's Johnson Space Center was spent working in the Structural Engineering Division's Structures Branch. One of the two main roles of the Structures Branch, ES2, is to ensure the structural integrity of spacecraft vehicles and the structural subsystems needed to support those vehicles. The other main objective of this branch is to develop the lightweight structures that are necessary to take humans beyond Low-Earth Orbit. Within ES2, my four projects involved inflatable space structure air bladder material testing; thermal and impact material testing for spacecraft windows; structural analysis on a joint used in the Boeing CST-100 airbag system; and an additive manufacturing design project.

  4. Nanoscale carbon materials from hydrocarbons pyrolysis: Structure, chemical behavior, utilisation for non-aqueous supercapacitors

    International Nuclear Information System (INIS)

    Savilov, Serguei V.; Strokova, Natalia E.; Ivanov, Anton S.; Arkhipova, Ekaterina A.; Desyatov, Andrey V.; Hui, Xia; Aldoshin, Serguei M.; Lunin, Valery V.

    2015-01-01

    Highlights: • N-doped and regular carbon nanomaterials were obtained by pyrolitic technique. • Dynamic vapor sorption of different solvents reveals smaller S BET values. • Steric hindrance and specific chemical interactions are the reasons for this. • Nitrogen doping leads to raise of capacitance and coulombic efficiency with non-aqueous N-containing electrolyte. - Abstract: This work systematically studies adsorption properties of carbon nanomaterials that are synthesized through hydrocarbons that is a powerful technique to fabricate different kinds of carbon materials, e.g., nanotubes, nanoshells, onions, including nitrogen substituted. The adsorption properties of the as-synthesized carbons are achieved by low temperature nitrogen adsorption and organic vapors sorption. Heptane, acetonitrile, water, ethanol, benzene and 1-methylimidazole, which are of great importance for development of supercapacitors, are used as substrates. It is discovered that while nitrogen adsorption reveals a high specific surface area, this parameter for most of organic compounds is rather small depending not only on the size of its molecule but also on chemical interactions for a pair adsorbent–adsorbate. The experimental values of heat of adsorption for carbon and N-substituted structures, when Coulomb cross-coupling of nitrogen atoms in adsorbent and adsorbate takes place, confirms this supposition

  5. Nanoscale carbon materials from hydrocarbons pyrolysis: Structure, chemical behavior, utilisation for non-aqueous supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Savilov, Serguei V., E-mail: savilov@chem.msu.ru [Lomonosov Moscow State University, Chemistry Department (Russian Federation); Strokova, Natalia E.; Ivanov, Anton S.; Arkhipova, Ekaterina A. [Lomonosov Moscow State University, Chemistry Department (Russian Federation); Desyatov, Andrey V. [D. Mendeleyev University of Chemical Technology of Russia (Russian Federation); Hui, Xia [Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology (China); Aldoshin, Serguei M. [Lomonosov Moscow State University, Faculty of Fundamental Physical and Chemical Engineering (Russian Federation); Lunin, Valery V. [Lomonosov Moscow State University, Chemistry Department (Russian Federation)

    2015-09-15

    Highlights: • N-doped and regular carbon nanomaterials were obtained by pyrolitic technique. • Dynamic vapor sorption of different solvents reveals smaller S{sub BET} values. • Steric hindrance and specific chemical interactions are the reasons for this. • Nitrogen doping leads to raise of capacitance and coulombic efficiency with non-aqueous N-containing electrolyte. - Abstract: This work systematically studies adsorption properties of carbon nanomaterials that are synthesized through hydrocarbons that is a powerful technique to fabricate different kinds of carbon materials, e.g., nanotubes, nanoshells, onions, including nitrogen substituted. The adsorption properties of the as-synthesized carbons are achieved by low temperature nitrogen adsorption and organic vapors sorption. Heptane, acetonitrile, water, ethanol, benzene and 1-methylimidazole, which are of great importance for development of supercapacitors, are used as substrates. It is discovered that while nitrogen adsorption reveals a high specific surface area, this parameter for most of organic compounds is rather small depending not only on the size of its molecule but also on chemical interactions for a pair adsorbent–adsorbate. The experimental values of heat of adsorption for carbon and N-substituted structures, when Coulomb cross-coupling of nitrogen atoms in adsorbent and adsorbate takes place, confirms this supposition.

  6. First Principles Modeling of Phonon Heat Conduction in Nanoscale Crystalline Structures

    International Nuclear Information System (INIS)

    Mazumder, Sandip; Li, Ju

    2010-01-01

    of optical phonons, and (2) by developing a suite of numerical algorithms for solution of the BTE for phonons. The suite of numerical algorithms includes Monte Carlo techniques and deterministic techniques based on the Discrete Ordinates Method and the Ballistic-Diffusive approximation of the BTE. These methods were applied to calculation of thermal conductivity of silicon thin films, and to simulate heat conduction in multi-dimensional structures. In addition, thermal transport in silicon nanowires was investigated using two different first principles methods. One was to apply the Green-Kubo formulation to an equilibrium system. The other was to use Non-Equilibrium Molecular Dynamics (NEMD). Results of MD simulations showed that the nanowire cross-sectional shape and size significantly affects the thermal conductivity, as has been found experimentally. In summary, the project clarified the role of various phonon modes - in particular, optical phonon - in non-equilibrium transport in silicon. It laid the foundation for the solution of the BTE in complex three-dimensional structures using deterministic techniques, paving the way for the development of robust numerical tools that could be coupled to existing device simulation tools to enable coupled electro-thermal modeling of practical electronic/optoelectronic devices. Finally, it shed light on why the thermal conductivity of silicon nanowires is so sensitive to its cross-sectional shape.

  7. Atomic Resolution Imaging of Nanoscale Structural Ordering in a Complex Metal Oxide Catalyst

    KAUST Repository

    Zhu, Yihan

    2012-08-28

    The determination of the atomic structure of a functional material is crucial to understanding its "structure-to-property" relationship (e.g., the active sites in a catalyst), which is however challenging if the structure possesses complex inhomogeneities. Here, we report an atomic structure study of an important MoVTeO complex metal oxide catalyst that is potentially useful for the industrially relevant propane-based BP/SOHIO process. We combined aberration-corrected scanning transmission electron microscopy with synchrotron powder X-ray crystallography to explore the structure at both nanoscopic and macroscopic scales. At the nanoscopic scale, this material exhibits structural and compositional order within nanosized "domains", while the domains show disordered distribution at the macroscopic scale. We proposed that the intradomain compositional ordering and the interdomain electric dipolar interaction synergistically induce the displacement of Te atoms in the Mo-V-O channels, which determines the geometry of the multifunctional metal oxo-active sites.

  8. Performance and Structural Evolution of Nano-Scale Infiltrated Solid Oxide Fuel Cell Cathodes

    Science.gov (United States)

    Call, Ann Virginia

    Nano-structured mixed ionic and electronic conducting (MIEC) materials have garnered intense interest in electrode development for solid oxide fuel cells due to their high surface areas which allow for effective catalytic activity and low polarization resistances. In particular, composite solid oxide fuel cell (SOFC) cathodes consisting of ionic conducting scaffolds infiltrated with MIEC nanoparticles have exhibited some of the lowest reported polarization resistances. In order for cells utilizing nanostructured moRPhologies to be viable for commercial implementation, more information on their initial performance and long term stability is necessary. In this study, symmetric cell cathodes were prepared via wet infiltration of Sr0.5Sm 0.5CoO3 (SSC) nano-particles via a nitrate process into porous Ce0.9Gd0.1O1.95 (GDC) scaffolds to be used as a model system to investigate performance and structural evolution. Detailed analysis of the cells and cathodes was carried out using electrochemical impedance spectroscopy (EIS). Initial polarization resistances (RP) as low as 0.11 O cm2 at 600ºC were obtained for these SSC-GDC cathodes, making them an ideal candidate for studying high performance nano-structured electrodes. The present results show that the infiltrated cathode microstructure has a direct impact on the initial performance of the cell. Small initial particle sizes and high infiltration loadings (up to 30 vol% SSC) improved initial RP. A simple microstructure-based electrochemical model successfully explained these trends in RP. Further understanding of electrode performance was gleaned from fitting EIS data gathered under varying temperatures and oxygen partial pressures to equivalent circuit models. Both RQ and Gerischer impedance elements provided good fits to the main response in the EIS data, which was associated with the combination of oxygen surface exchange and oxygen diffusion in the electrode. A gas diffusion response was also observed at relatively

  9. Engineering of Nanoscale Antifouling and Hydrophobic Surfaces on Naval Structural Steel HY-80 by Anodizing

    Science.gov (United States)

    2015-06-01

    stainless steel by anodization. The oxide structures produced under these conditions granted the material significant visible light photo catalytic...metallurgically classified as quenched and tempered martensitic steels . They have a martensitic microstructure resulting from the 9 combination of...producing a martensitic structure is carbon. The as-quenched steel manifests high strength and hardness but also is brittle and susceptible to hydrogen

  10. Structural evolution of plasma-sprayed nanoscale 3 mol% and 5 mol% yttria-stabilized zirconia coatings during sintering

    Science.gov (United States)

    Zhao, Yan; Gao, Yang

    2017-12-01

    The microstructure of plasma-sprayed nanostructured yttria-stabilized zirconia (YSZ) coatings may change during high-temperature exposure, which would influence the coating performance and service lifetime. In this study, the phase structure and the microstructural evolution of 3YSZ (zirconia-3 mol% yttria) and 5YSZ (zirconia-5 mol% yttria) nanostructured coatings were investigated by means of sintering at 1400 °C for 50-100 h. The microhardness, elastic moduli, and thermal shock cycles of the 3YSZ and 5YSZ nanostructured coatings were also investigated. The results showed that the redistribution of yttrium ions at 1400 °C caused the continuous increase of monoclinic-phase zirconia, but no obvious inter-splat cracking formed at the cross-sections, even after 100 h. Large voids appeared around the nanoporous zone because of the sintering of nanoscale granules upon high-temperature exposure. The microhardness and elastic moduli of the nanostructured coatings first increased and then decreased with increasing sintering times. The growth rate of the nanograins in the 3YSZ coating was lower than that in 5YSZ, which slowed the changes in 3YSZ coating porosity during sintering. Although the 3YSZ coating was prone to monoclinic phase transition, the experimental results showed that the thermal shock resistance of the 3YSZ coating was better than that of the 5YSZ coating.

  11. Cellular behavior on TiO2 nanonodular structures in a micro-to-nanoscale hierarchy model.

    Science.gov (United States)

    Kubo, Katsutoshi; Tsukimura, Naoki; Iwasa, Fuminori; Ueno, Takeshi; Saruwatari, Lei; Aita, Hideki; Chiou, Wen-An; Ogawa, Takahiro

    2009-10-01

    Biological tissues involve hierarchical organizations of structures and components. We created a micropit-and-nanonodule hybrid topography of TiO(2) by applying a recently reported nanonodular self-assembly technique on acid-etch-created micropit titanium surfaces. The size of the nanonodules was controllable by changing the assembly time. The created micro-nano-hybrid surface rendered a greater surface area and roughness, and extensive geographical undercut on the existing micropit surface and resembled the surface morphology of biomineralized matrices. Rat bone marrow-derived osteoblasts were cultured on titanium disks with either micropits alone, micropits with 100-nm nodules, micropits with 300-nm nodules, or micropits with 500-nm nodules. The addition of nanonodules to micropits selectively promoted osteoblast but not fibroblast function. Unlike the reported advantages of microfeatures that promote osteoblast differentiation but inhibit its proliferation, micro-nano-hybrid topography substantially enhanced both. We also demonstrated that these biological effects were most pronounced when the nanonodules were tailored to a diameter of 300nm within the micropits. An implant biomechanical test in a rat femur model revealed that the strength of bone-titanium integration was more than three times greater for the implants with micropits and 300-nm nanonodules than the implants with micropits alone. These results suggest the establishment of functionalized nano-in-microtitanium surfaces for improved osteoconductivity, and may provide a biomimetic micro-to-nanoscale hierarchical model to study the nanofeatures of biomaterials.

  12. Enhanced osteointegration of medical titanium implant with surface modifications in micro/nanoscale structures

    Directory of Open Access Journals (Sweden)

    Liwen Lin

    2014-01-01

    Full Text Available Biomimetic design and substrate-based surface modification of medical implants will help to improve the integration of tissue to its material interfaces. Surface energy, composition, roughness, and topography all influence the biological responses of the implants, such as protein adsorption and cell adhesion, proliferation and differentiation. In the current study, different surface structures of Ti implants were constructed using facile surface techniques to create various micro-, nano-, and nano/micro composite scale topography. We have fabricated three types of hierarchical structures of TiO2 coating on Ti implants, including nanotube structure, nano sponge-like structure, and nano/micro nest-like structure. The osteointegration and biomechanical performance of the coated Ti screws were evaluated by histology and removal of torque force test in vivo. We found that the nano/micro nest-like and nanotube structured surface possessed better osteointegration ability. It indicated that the alkaline hydrothermally treated Ti substrate was the best for bone-implant integration in terms of all in vitro and in vivo testing parameters. The alkaline hydrothermally treated surface displayed a hydrophilic (contact angle value 5.92 ± 1.2, higher roughness (Ra value 911.3 ± 33.8 nm, higher specific surface area (8.26 ± 1.051 m2/g, and greater apatite inductivity. The electrochemical surface modification may become a powerful approach to enhance metal implant to bone integration in orthopaedic applications.

  13. Investigation of Amyloid Structures at Nanoscale via AFM based Dynamic Nanomechncial Microscopy

    DEFF Research Database (Denmark)

    Zhang, Shuai

    2014-01-01

    Amyloid structures are one important kind of protein aggregations. They are a group of stable misfolded species, other than native states, which have been found to accumulate as plaques on neuron cells. This behavior is considered to associate with tens of human neurodegenerative diseases...... summarized the main methodologies of DNM. I also utilized DNM to explore the path way of amyloid self-assembly, and the substrate effect to the conformation of amyloid structures. Furthermore, 2D peptide based material has also been characterized by DNM....

  14. Phase behavior and nanoscale structure of phospholipid membranes incorporated with acylated C-14-peptides

    DEFF Research Database (Denmark)

    Pedersen, T.B.; Kaasgaard, Thomas; Jensen, M.O.

    2005-01-01

    The thermotropic phase behavior and lateral structure of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers containing an acylated peptide has been characterized by differential scanning calorimetry (DSC) on vesicles and atomic force microscopy (AFM) on mica-supported bilayers. The acylated...... peptide, which is a synthetic decapeptide N-terminally linked to a C-14 acyl chain (C-14-peptide), is incorporated into DPPC bilayers in amounts ranging from 0-20 mol %. The calorimetric scans of the two-component system demonstrate a distinct influence of the C-14-peptide on the lipid bilayer...... gel phase DPPC bilayers, inserts preferentially into preexisting defect regions and has a noticeable influence on the organization of the surrounding lipids. The presence of the C-14-peptide gives rise to a laterally heterogeneous bilayer structure with coexisting lipid domains characterized by a 10...

  15. Nanoscale structural heterogeneity in Ni-rich half-Heusler TiNiSn

    International Nuclear Information System (INIS)

    Douglas, Jason E.; Pollock, Tresa M.; Chater, Philip A.; Brown, Craig M.; Seshadri, Ram

    2014-01-01

    The structural implications of excess Ni in the TiNiSn half-Heusler compound are examined through a combination of synchrotron x-ray and neutron scattering studies, in conjunction with first principles density functional theory calculations on supercells. Despite the phase diagram suggesting that TiNiSn is a line compound with no solid solution, for small x in TiNi 1+x Sn there is indeed an appearance—from careful analysis of the scattering—of some solubility, with the excess Ni occupying the interstitial tetrahedral site in the half-Heusler structure. The analysis performed here would point to the excess Ni not being statistically distributed, but rather occurring as coherent nanoclusters. First principles calculations of energetics, carried out using supercells, support a scenario of Ni interstitials clustering, rather than a statistical distribution.

  16. Enhanced osteointegration of medical titanium implant with surface modifications in micro/nanoscale structures

    OpenAIRE

    Lin, Liwen; Wang, Hui; Ni, Ming; Rui, Yunfeng; Cheng, Tian-Yuan; Cheng, Cheng-Kung; Pan, Xiaohua; Li, Gang; Lin, Changjian

    2014-01-01

    Biomimetic design and substrate-based surface modification of medical implants will help to improve the integration of tissue to its material interfaces. Surface energy, composition, roughness, and topography all influence the biological responses of the implants, such as protein adsorption and cell adhesion, proliferation and differentiation. In the current study, different surface structures of Ti implants were constructed using facile surface techniques to create various micro-, nano-, and...

  17. Nanoscale discontinuities at the boundary of flowing liquids: a look into structure

    International Nuclear Information System (INIS)

    Wolff, Max; Gutfreund, Philipp; Zabel, Hartmut; Ruehm, Adrian; Akgun, Bulent

    2011-01-01

    When downsizing technology, confinement and interface effects become enormously important. Shear imposes additional anisotropy on a liquid. This may induce inhomogeneities, which may have their origin close to the solid interface. For advancing the understanding of flow, information on structures on all length scales and in particular close to the solid interface is indispensable. Neutron scattering offers an excellent tool to contribute in this context. In this work, surface sensitive scattering techniques were used to resolve the structure of liquids under flow in the vicinity of a solid interface. Our results are summarized as follows. First, for a Newtonian liquid we report a depletion distance on the order of nanometers which is far too small to explain the amount of surface slip, on the order of micrometers, found by complementary techniques. Second, for a grafted polymer brush we find no entanglement-disentanglement transition under shear but the grafted film gets ripped off the surface. Third, by evaluating the local structure factor of a micellar solution close to the solid interface it turns out that the degree of order and local relaxation depends critically on the surface energy of the solid surface.

  18. Effect of nanoscale flows on the surface structure of nanoporous catalysts.

    Science.gov (United States)

    Montemore, Matthew M; Montessori, Andrea; Succi, Sauro; Barroo, Cédric; Falcucci, Giacomo; Bell, David C; Kaxiras, Efthimios

    2017-06-07

    The surface structure and composition of a multi-component catalyst are critical factors in determining its catalytic performance. The surface composition can depend on the local pressure of the reacting species, leading to the possibility that the flow through a nanoporous catalyst can affect its structure and reactivity. Here, we explore this possibility for oxidation reactions on nanoporous gold, an AgAu bimetallic catalyst. We use microscopy and digital reconstruction to obtain the morphology of a two-dimensional slice of a nanoporous gold sample. Using lattice Boltzmann fluid dynamics simulations along with thermodynamic models based on first-principles total-energy calculations, we show that some sections of this sample have low local O 2 partial pressures when exposed to reaction conditions, which leads to a pure Au surface in these regions, instead of the active bimetallic AgAu phase. We also explore the effect of temperature on the surface structure and find that moderate temperatures (≈300-450 K) should result in the highest intrinsic catalytic performance, in apparent agreement with experimental results.

  19. Magnonic band structure, complete bandgap, and collective spin wave excitation in nanoscale two-dimensional magnonic crystals

    International Nuclear Information System (INIS)

    Kumar, D.; Barman, A.; Kłos, J. W.; Krawczyk, M.

    2014-01-01

    We present the observation of a complete bandgap and collective spin wave excitation in two-dimensional magnonic crystals comprised of arrays of nanoscale antidots and nanodots, respectively. Considering that the frequencies dealt with here fall in the microwave band, these findings can be used for the development of suitable magnonic metamaterials and spin wave based signal processing. We also present the application of a numerical procedure, to compute the dispersion relations of spin waves for any high symmetry direction in the first Brillouin zone. The results obtained from this procedure have been reproduced and verified by the well established plane wave method for an antidot lattice, when magnetization dynamics at antidot boundaries are pinned. The micromagnetic simulation based method can also be used to obtain iso–frequency contours of spin waves. Iso–frequency contours are analogous of the Fermi surfaces and hence, they have the potential to radicalize our understanding of spin wave dynamics. The physical origin of bands, partial and full magnonic bandgaps have been explained by plotting the spatial distribution of spin wave energy spectral density. Although, unfettered by rigid assumptions and approximations, which afflict most analytical methods used in the study of spin wave dynamics, micromagnetic simulations tend to be computationally demanding. Thus, the observation of collective spin wave excitation in the case of nanodot arrays, which can obviate the need to perform simulations, may also prove to be valuable

  20. Structural, electronic, optical and vibrational properties of nanoscale carbons and nanowires: a colloquial review.

    Science.gov (United States)

    Cole, Milton W; Crespi, Vincent H; Dresselhaus, Mildred S; Dresselhaus, Gene; Fischer, John E; Gutierrez, Humberto R; Kojima, K; Mahan, Gerald D; Rao, Apparao M; Sofo, Jorge O; Tachibana, M; Wako, K; Xiong, Qihua

    2010-08-25

    This review addresses the field of nanoscience as viewed through the lens of the scientific career of Peter Eklund, thus with a special focus on nanocarbons and nanowires. Peter brought to his research an intense focus, imagination, tenacity, breadth and ingenuity rarely seen in modern science. His goal was to capture the essential physics of natural phenomena. This attitude also guides our writing: we focus on basic principles, without sacrificing accuracy, while hoping to convey an enthusiasm for the science commensurate with Peter's. The term 'colloquial review' is intended to capture this style of presentation. The diverse phenomena of condensed matter physics involve electrons, phonons and the structures within which excitations reside. The 'nano' regime presents particularly interesting and challenging science. Finite size effects play a key role, exemplified by the discrete electronic and phonon spectra of C(60) and other fullerenes. The beauty of such molecules (as well as nanotubes and graphene) is reflected by the theoretical principles that govern their behavior. As to the challenge, 'nano' requires special care in materials preparation and treatment, since the surface-to-volume ratio is so high; they also often present difficulties of acquiring an experimental signal, since the samples can be quite small. All of the atoms participate in the various phenomena, without any genuinely 'bulk' properties. Peter was a master of overcoming such challenges. The primary activity of Eklund's research was to measure and understand the vibrations of atoms in carbon materials. Raman spectroscopy was very dear to Peter. He published several papers on the theory of phonons (Eklund et al 1995a Carbon 33 959-72, Eklund et al 1995b Thin Solid Films 257 211-32, Eklund et al 1992 J. Phys. Chem. Solids 53 1391-413, Dresselhaus and Eklund 2000 Adv. Phys. 49 705-814) and many more papers on measuring phonons (Pimenta et al 1998b Phys. Rev. B 58 16016-9, Rao et al 1997a Nature

  1. Structural, electronic, optical and vibrational properties of nanoscale carbons and nanowires: a colloquial review

    International Nuclear Information System (INIS)

    Cole, Milton W; Crespi, Vincent H; Dresselhaus, Mildred S; Dresselhaus, Gene; Fischer, John E; Gutierrez, Humberto R; Kojima, K; Wako, K; Mahan, Gerald D; Rao, Apparao M; Sofo, Jorge O; Tachibana, M; Xiong Qihua

    2010-01-01

    This review addresses the field of nanoscience as viewed through the lens of the scientific career of Peter Eklund, thus with a special focus on nanocarbons and nanowires. Peter brought to his research an intense focus, imagination, tenacity, breadth and ingenuity rarely seen in modern science. His goal was to capture the essential physics of natural phenomena. This attitude also guides our writing: we focus on basic principles, without sacrificing accuracy, while hoping to convey an enthusiasm for the science commensurate with Peter's. The term 'colloquial review' is intended to capture this style of presentation. The diverse phenomena of condensed matter physics involve electrons, phonons and the structures within which excitations reside. The 'nano' regime presents particularly interesting and challenging science. Finite size effects play a key role, exemplified by the discrete electronic and phonon spectra of C 60 and other fullerenes. The beauty of such molecules (as well as nanotubes and graphene) is reflected by the theoretical principles that govern their behavior. As to the challenge, 'nano' requires special care in materials preparation and treatment, since the surface-to-volume ratio is so high; they also often present difficulties of acquiring an experimental signal, since the samples can be quite small. All of the atoms participate in the various phenomena, without any genuinely 'bulk' properties. Peter was a master of overcoming such challenges. The primary activity of Eklund's research was to measure and understand the vibrations of atoms in carbon materials. Raman spectroscopy was very dear to Peter. He published several papers on the theory of phonons (Eklund et al 1995a Carbon 33 959-72, Eklund et al 1995b Thin Solid Films 257 211-32, Eklund et al 1992 J. Phys. Chem. Solids 53 1391-413, Dresselhaus and Eklund 2000 Adv. Phys. 49 705-814) and many more papers on measuring phonons (Pimenta et al 1998b Phys. Rev. B 58 16016-9, Rao et al 1997a Nature

  2. Self assembly of amphiphilic C60 fullerene derivatives into nanoscale supramolecular structures

    Directory of Open Access Journals (Sweden)

    Casscells S Ward

    2007-08-01

    Full Text Available Abstract Background The amphiphilic fullerene monomer (AF-1 consists of a "buckyball" cage to which a Newkome-like dendrimer unit and five lipophilic C12 chains positioned octahedrally to the dendrimer unit are attached. In this study, we report a novel fullerene-based liposome termed 'buckysome' that is water soluble and forms stable spherical nanometer sized vesicles. Cryogenic electron microscopy (Cryo-EM, transmission electron microscopy (TEM, and dynamic light scattering (DLS studies were used to characterize the different supra-molecular structures readily formed from the fullerene monomers under varying pH, aqueous solvents, and preparative conditions. Results Electron microscopy results indicate the formation of bilayer membranes with a width of ~6.5 nm, consistent with previously reported molecular dynamics simulations. Cryo-EM indicates the formation of large (400 nm diameter multilamellar, liposome-like vesicles and unilamellar vesicles in the size range of 50–150 nm diameter. In addition, complex networks of cylindrical, tube-like aggregates with varying lengths and packing densities were observed. Under controlled experimental conditions, high concentrations of spherical vesicles could be formed. In vitro results suggest that these supra-molecular structures impose little to no toxicity. Cytotoxicity of 10–200 μM buckysomes were assessed in various cell lines. Ongoing studies are aimed at understanding cellular internalization of these nanoparticle aggregates. Conclusion In this current study, we have designed a core platform based on a novel amphiphilic fullerene nanostructure, which readily assembles into supra-molecular structures. This delivery vector might provide promising features such as ease of preparation, long-term stability and controlled release.

  3. PRSEUS Structural Concept Development

    Science.gov (United States)

    Velicki, Alex; Jegley, Dawn

    2014-01-01

    A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

  4. Structure evolution and magnetic properties of annealed nanoscale Gd/Ti multilayers

    Directory of Open Access Journals (Sweden)

    Larrañaga A.

    2013-01-01

    Full Text Available The structure and magnetic properties were comparatively analyzed for [Gd/Ti]n multilayers with Gd layer thickness of 1.5 to 12 nm. Multilayers were deposited by sputtering technique at room temperature and annealed for the temperatures up to 400 ºC. It was observed that the samples are highly textured in a different way depending on the Gd layer thickness and annealing temperature. It was found that the heat treatment practically does not change the Gd grain size. The lattice parameters obtained from X-ray results change significantly only for [Gd(1.5nm/Ti]50 multilayers, but their values remain higher than for the bulk Gd. The initial slope of the temperature dependence of magnetization near Curie temperature becomes steeper and Curie temperature increases upon annealing. Curie temperature variation can be understood by taking into account both relaxation of the lattice imperfections and change in lattice constants.

  5. Electronic and structural properties of TiB2: Bulk, surface, and nanoscale effects

    International Nuclear Information System (INIS)

    Volonakis, George; Tsetseris, Leonidas; Logothetidis, Stergios

    2011-01-01

    Titanium diboride (TiB 2 ), is a widely used hard material that comprises graphene-like layers of B and intercalated Ti atoms. Here we report the results of extensive first-principles calculations on key properties of bulk TiB 2 , TiB 2 surfaces, and TiB 2 nanocrystals (NCs). The computational approach is first validated based on the agreement between calculated structural and electronic properties of bulk TiB 2 and available experimental and theoretical data. We then obtain the formation energies for several surface cuts and use these values to construct TiB 2 NCs based on the Wulff theorem. Finally, we demonstrate by studying the adsorption of small molecules that hydrogen and oxygen adatoms can be attached through strongly exothermic chemisorption reactions on TiB 2 surfaces. Likewise, water molecules bind on various TiB 2 surfaces and NC facets, with an energetic preference for the latter. The results are relevant to applications that depend on reactivity-related TiB 2 properties, for example resistance to corrosion and interactions with water-based solutions.

  6. Expert Cold Structure Development

    Science.gov (United States)

    Atkins, T.; Demuysere, P.

    2011-05-01

    The EXPERT Program is funded by ESA. The objective of the EXPERT mission is to perform a sub-orbital flight during which measurements of critical aero- thermodynamic phenomena will be obtained by using state-of-the-art instrumentation. As part of the EXPERT Flight Segment, the responsibility of the Cold Structure Development Design, Manufacturing and Validation was committed to the Belgian industrial team SONACA/SABCA. The EXPERT Cold Structure includes the Launcher Adapter, the Bottom Panel, the Upper Panel, two Cross Panels and the Parachute Bay. An additional Launcher Adapter was manufactured for the separation tests. The selected assembly definition and manufacturing technologies ( machined parts and sandwich panels) were dictated classically by the mass and stiffness, but also by the CoG location and the sensitive separation interface. Used as support for the various on-board equipment, the Cold Structure is fixed to but thermally uncoupled from the PM 1000 thermal shield. It is protect on its bottom panel by a thermal blanket. As it is a protoflight, analysis was the main tool for the verification. Low level stiffness and modal analysis tests have also been performed on the Cold Structure equipped with its ballast. It allowed to complete its qualification and to prepare SONACA/SABCA support for the system dynamic tests foreseen in 2011. The structure was finally coated with a thermal control black painting and delivered on time to Thales Alenia Space-Italy end of March 201.

  7. Structure, microstructure and magnetic properties of electrodeposited Co and Co-Pt in different nanoscale geometries

    Energy Technology Data Exchange (ETDEWEB)

    Khatri, Manvendra Singh

    2010-07-09

    Thin films and nanowires of Co-Pt have been prepared by means of electrodeposition. Composition, structure, microstructure and magnetic properties have been intensively studied using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry and correlated to the deposition parameters such as electrolyte composition, deposition current and/or potential. Co rich Co-Pt films have been deposited at various current densities. A nearly constant composition of Co{sub 70}Pt{sub 30} was achieved for current densities between 18 and 32 mA/cm{sup 2}. Detailed texture measurements confirmed an increasing fraction of the hexagonal phase with its c-axis aligned perpendicular to the film plane with increasing current density. Accordingly, magnetic properties are strongly affected by the magnetocrystalline anisotropy of the hexagonal phase that competes with the shape anisotropy of the thin film geometry. Co-Pt nanowires have been prepared within alumina templates at different deposition potentials between -0.6 and -0.9 V{sub SCE} changing the composition from nearly pure Pt to Co. The composition Co{sub 80}Pt{sub 20} was observed at a deposition potential of -0.7 V{sub SCE}. Co-Pt nanowires are nanocrystalline in the as-deposited state. Magnetic measurements reveal changing fcc and hcp phase fractions within the wires as the effective anisotropy significantly differs from the expected shape anisotropy for nanowires with high aspect ratio. This change in effective anisotropy is attributed to the preferential alignment of the c-axis of hcp Co-Pt phase perpendicular to the nanowires axis. A promising alternative with much smaller feature sizes is the diblock copolymer template. Electrodeposition of Co and Co-Pt into these templates has been carried out. Inhomogeneities in the template thickness as well as a certain substrate roughness have been identified to be the reasons for inhomogeneous template filling. Thus magnetic properties are dominated by large

  8. Nanoscale effects in interdiffusion

    International Nuclear Information System (INIS)

    Erdelyi, Z.; Langer, G.A.; Beke, D.L.; Csik, A.

    2007-01-01

    Complete text of publication follows. Diffusion on the nano/atomic scales in multilayers, thin films has many challenging features even if the role of structural defects can be neglected and 'only' the effects related to the nano/atomic scale raise. The most basic equations to describe the diffusion are Fick's equations. It is important to emphasize that the diffusion coefficient in Fick's equations is in general composition independent and Fick's classical equations do not include the stress effects, which can have important influence onto the diffusion especially on the nano/atomic scale. We illustrate that the continuum descriptions of the diffusion cannot be applied automatically on such short distances, the classical continuum approximations (Fick's laws) cannot describe correctly the atomic movements. They predict faster kinetics than the atomistic models and the interface shift is always proportional to the square root of the time. However, the kinetics can be even linear on the nano/atomic scale. We have shown from computer simulations that Fick's laws violate on the nanoscale either in completely or restricted miscible systems. This is strongly related to the discrete character of the system on the nanoscale and to the highly neglected fact in the literature that the diffusion coefficients depend on the composition. As will be seen the composition dependence of D is very important and has very significant influence on the diffusion kinetics on the nano/atomic scales. It originates from the fact that usually the diffusion coefficients are different in an A and in a B matrix. Consequently in case of a real interface, which is not atomically sharp, i.e. there is a more or less intermixed region between the pure A and B matrixes, the diffusion coefficient changes continuously while e.g. an A atom diffuses from the pure A matrix into the pure B. This feature can be also called diffusion asymmetry. We have also illustrated that in this case not only the

  9. Developing fair compensation structures

    International Nuclear Information System (INIS)

    Trousdale, W.J.

    1998-01-01

    The issue of finding an effective way to incorporate Aboriginal values into the process of developing fair compensation structures was discussed. This paper discusses pricing intangible values using dollars, but it was emphasized that 'values' are whatever are important to us. Therefore, in order to achieve fair compensation, creative alternatives that are value-focused should be pursued. In addition to the more straight-forward monetary compensation, compensation could also be about avoiding losses, mitigating adverse impacts, achieving better communication, and promoting cultural understanding. 25 refs., 2 tabs

  10. Nano-scale analysis of titanium dioxide fingerprint-development powders

    International Nuclear Information System (INIS)

    Reynolds, A J; Jones, B J; Sears, V; Bowman, V

    2008-01-01

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO 2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO 2 particles and efficacy of print development.

  11. Nano-scale analysis of titanium dioxide fingerprint-development powders

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A J; Jones, B J [Experimental Techniques Centre, Brunei University, Kingston Lane, Uxbridge, Middlesex, UB8 3PH (United Kingdom); Sears, V; Bowman, V [Fingerprint and Footwear Forensics, Home Office Scientific Development Branch, Sandridge, St Albans, Hertfordshire, AL4 9HQ (United Kingdom)], E-mail: b.j.jones@physics.org

    2008-08-15

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO{sub 2} particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO{sub 2} particles and efficacy of print development.

  12. Structural Modification and Self-Assembly of Nanoscale Magnetite Synthesised in the Presence of an Anionic Surfactant

    Directory of Open Access Journals (Sweden)

    Malik S.

    2014-07-01

    Full Text Available The earliest reported medical use of magnetite powder for internal applications was in the 10th century A.D. by the Persian physician and philosopher Avicenna of Bokhara [1,2]. Today magnetic nanoparticles are used for magnetic resonance imaging (MRI and are potential colloidal mediators for cancer magnetic hyperthermia [3]. Twenty years ago magnetite (Fe3O4 was found to be present in the human brain [4] and more recently it has been reported that nanoscale biogenic magnetite (origin and formation uncertain is associated with neurodegenerative diseases such as Parkinson’s, Huntington’s and Alzheimer’s [5]. Here we show that the synthesis of magnetite in the presence of the surfactant sodium dodecyl sulphate (SDS gives rise to a variety of nanoscale morphologies, some of which look remarkably similar to magnetite found in organisms, suggesting that similar processes may be involved. Furthermore, these 1D materials with diameters of quantum confined size are of interest in the areas of biosensors [6] and biomedical imaging [7].

  13. Investigation of the Structural, Electrical, and Optical Properties of the Nano-Scale GZO Thin Films on Glass and Flexible Polyimide Substrates

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2016-05-01

    Full Text Available In this study, Ga2O3-doped ZnO (GZO thin films were deposited on glass and flexible polyimide (PI substrates at room temperature (300 K, 373 K, and 473 K by the radio frequency (RF magnetron sputtering method. After finding the deposition rate, all the GZO thin films with a nano-scale thickness of about 150 ± 10 nm were controlled by the deposition time. X-ray diffraction patterns indicated that the GZO thin films were not amorphous and all exhibited the (002 peak, and field emission scanning electron microscopy showed that only nano-scale particles were observed. The dependences of the structural, electrical, and optical properties of the GZO thin films on different deposition temperatures and substrates were investigated. X-ray photoemission spectroscopy (XPS was used to measure the elemental composition at the chemical and electronic states of the GZO thin films deposited on different substrates, which could be used to clarify the mechanism of difference in electrical properties of the GZO thin films. In this study, the XPS binding energy spectra of Ga2p3/2 and Ga2p1/2 peaks, Zn2p3/2 and Zn2p1/2 peaks, the Ga3d peak, and O1s peaks for GZO thin films on glass and PI substrates were well compared.

  14. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael A.; Shen, Zhi-Xun

    2011-01-01

    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.

  15. 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

  16. 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.

  17. Nanoscale Characterization for the Classroom

    International Nuclear Information System (INIS)

    Carroll, D.L.

    1999-01-01

    This report describes the development of a semester course in 'nano-scale characterization'. The interdisciplinary course is opened to both advanced undergraduate and graduate students with a standard undergraduate preparation in Materials Science, Chemistry, or Physics. The approach is formal rather than the typical 'research seminar' and has a laboratory component

  18. Electromagnetic Modelling of Raman Enhancement from Nanoscale Structures as a Means to Predict the Efficacy of SERS Substrates

    Directory of Open Access Journals (Sweden)

    Richard J. C. Brown

    2007-01-01

    Full Text Available The requirement to optimise the balance between signal enhancement and reproducibility in surface enhanced Raman spectroscopy (SERS is stimulating the development of novel substrates for enhancing Raman signals. This paper describes the application of finite element electromagnetic modelling to predict the Raman enhancement produced from a variety of SERS substrates with differently sized, spaced and shaped morphologies with nanometre dimensions. For the first time, a theoretical comparison between four major generic types of SERS substrate (including metal nanoparticles, structured surfaces, and sharp tips has been performed and the results are presented and discussed. The results of the modelling are consistent with published experimental data from similar substrates.

  19. Sensing at the nanoscale

    Science.gov (United States)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    label-free detection of DNA at concentrations as low as 1-10 fM, a sensitivity comparable to the best signal amplification-assisted electrochemical sensors reported [12]. In another study actin-conjugated gold and silver nanorods are used to detect ATP, a common indicator of cell viability [13]. They show how aggregation induced by ATP-induced polymerization of the G-actin gives rise to a measurable change in the plasmon resonance absorbance of the nanorods. A review of the use of fluorescent silica nanoparticles for biomedical applications is provided by researchers at Dublin City University in Ireland [14]. The first scanning tunnelling microscope in the early 1980s and subsequent scanning probe developments brought the world of nanoscale structures into view in a manner that gorged the imaginations of scientists and the public. New ways of probing structures at this scale revealed a wealth of curious properties that triggered a surge of research activity in nanotechnology, now a multibillion dollar industry. One good turn deserves another and in fact nanostructures provide the perfect tools for the type of sensing and imaging applications that brought such widespread research interest to nanotechnology. This special issue highlights just how broad and innovative the range of sensing nanotechnologies has grown. References [1] Zappa D, Comini E and Sberveglieri G 2013 Thermally-oxidized zinc oxide nanowires chemical sensors Nanotechnology 24 444008 [2] Kemmler J A, Pokhrel S, Mädler L, Weimar U and Barsan N 2013 Flame spray pyrolysis for sensing at the nanoscale Nanotechnology 24 442001 [3] Bache M et al 2013 Nanomechanical recognition of prognostic biomarker suPAR with DVD-ROM optical technology Nanotechnology 24 444011 [4] Hu C-F, Wang J-Y, Liu Y-C, Tsai M-H and Fang W 2013 Development of 3D carbon nanotubes interdigitated finger electrodes on polymer substrate for flexible capacitive sensor application Nanotechnology 24 444006 [5] Neumann C, Volk C, Engels S and

  20. Nano-scale Biophysical and Structural Investigations on Intact and Neuropathic Nerve Fibers by Simultaneous Combination of Atomic Force and Confocal Microscopy

    Directory of Open Access Journals (Sweden)

    Gonzalo Rosso

    2017-08-01

    Full Text Available The links between neuropathies of the peripheral nervous system (PNS, including Charcot-Marie-Tooth1A and hereditary neuropathy with liability to pressure palsies, and impaired biomechanical and structural integrity of PNS nerves remain poorly understood despite the medical urgency. Here, we present a protocol describing simultaneous structural and biomechanical integrity investigations on isolated nerve fibers, the building blocks of nerves. Nerve fibers are prepared from nerves harvested from wild-type and exemplary PNS neuropathy mouse models. The basic principle of the designed experimental approach is based on the simultaneous combination of atomic force microscopy (AFM and confocal microscopy. AFM is used to visualize the surface structure of nerve fibers at nano-scale resolution. The simultaneous combination of AFM and confocal microscopy is used to perform biomechanical, structural, and functional integrity measurements at nano- to micro-scale. Isolation of sciatic nerves and subsequent teasing of nerve fibers take ~45 min. Teased fibers can be maintained at 37°C in a culture medium and kept viable for up to 6 h allowing considerable time for all measurements which require 3–4 h. The approach is designed to be widely applicable for nerve fibers from mice of any PNS neuropathy. It can be extended to human nerve biopsies.

  1. Nanoscale structure, dynamics and power conversion efficiency correlations in small molecule and oligomer-based photovoltaic devices

    Science.gov (United States)

    Szarko, Jodi M.; Guo, Jianchang; Rolczynski, Brian S.; Chen, Lin X.

    2011-01-01

    Photovoltaic functions in organic materials are intimately connected to interfacial morphologies of molecular packing in films on the nanometer scale and molecular levels. This review will focus on current studies on correlations of nanoscale morphologies in organic photovoltaic (OPV) materials with fundamental processes relevant to photovoltaic functions, such as light harvesting, exciton splitting, exciton diffusion, and charge separation (CS) and diffusion. Small molecule photovoltaic materials will be discussed here. The donor and acceptor materials in small molecule OPV devices can be fabricated in vacuum-deposited, multilayer, crystalline thin films, or spin-coated together to form blended bulk heterojunction (BHJ) films. These two methods result in very different morphologies of the solar cell active layers. There is still a formidable debate regarding which morphology is favored for OPV optimization. The morphology of the conducting films has been systematically altered; using variations of the techniques above, the whole spectrum of film qualities can be fabricated. It is possible to form a highly crystalline material, one which is completely amorphous, or an intermediate morphology. In this review, we will summarize the past key findings that have driven organic solar cell research and the current state-of-the-art of small molecule and conducting oligomer materials. We will also discuss the merits and drawbacks of these devices. Finally, we will highlight some works that directly compare the spectra and morphology of systematically elongated oligothiophene derivatives and compare these oligomers to their polymer counterparts. We hope this review will shed some new light on the morphology differences of these two systems. PMID:22110870

  2. Nanoscale zerovalent iron alters soil bacterial community structure and inhibits chloroaromatic biodegradation potential in Aroclor 1242-contaminated soil

    International Nuclear Information System (INIS)

    Tilston, Emma L.; Collins, Chris D.; Mitchell, Geoffrey R.; Princivalle, Jessica; Shaw, Liz J.

    2013-01-01

    Nanoscale zerovalent iron (nZVI) has potential for the remediation of organochlorine-contaminated environments. Environmental safety concerns associated with in situ deployment of nZVI include potential negative impacts on indigenous microbes whose biodegradative functions could contribute to contaminant remediation. With respect to a two-step polychlorinated biphenyl remediation scenario comprising nZVI dechlorination followed by aerobic biodegradation, we examined the effect of polyacrylic acid (PAA)-coated nZVI (mean diameter = 12.5 nm) applied at 10 g nZVI kg −1 to Aroclor-1242 contaminated and uncontaminated soil over 28 days. nZVI had a limited effect on Aroclor congener profiles, but, either directly or indirectly via changes to soil physico-chemical conditions (pH, Eh), nZVI addition caused perturbation to soil bacterial community composition, and reduced the activity of chloroaromatic mineralizing microorganisms. We conclude that nZVI addition has the potential to inhibit microbial functions that could be important for PCB remediation strategies combining nZVI treatment and biodegradation. Highlights: ► Impact of nano-sized zerovalent iron on microbes was investigated in soil microcosms. ► Zerovalent iron had short-lived effects on redox potential and Aroclor dechlorination. ► Microbial populations also showed short-lived perturbations in their size. ► The activity of chloroaromatic degrading microbes did not recover within 28 days. ► Zerovalent iron application inhibits ensuing PCB bioremediative microbial functions. - nZVI inhibits microbial functions of potential importance for remediation strategies combining nZVI treatment and biodegradation.

  3. Probabilistic Structural Analysis Theory Development

    Science.gov (United States)

    Burnside, O. H.

    1985-01-01

    The objective of the Probabilistic Structural Analysis Methods (PSAM) project is to develop analysis techniques and computer programs for predicting the probabilistic response of critical structural components for current and future space propulsion systems. This technology will play a central role in establishing system performance and durability. The first year's technical activity is concentrating on probabilistic finite element formulation strategy and code development. Work is also in progress to survey critical materials and space shuttle mian engine components. The probabilistic finite element computer program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) is being developed. The final probabilistic code will have, in the general case, the capability of performing nonlinear dynamic of stochastic structures. It is the goal of the approximate methods effort to increase problem solving efficiency relative to finite element methods by using energy methods to generate trial solutions which satisfy the structural boundary conditions. These approximate methods will be less computer intensive relative to the finite element approach.

  4. Nanoscale science and nanotechnology education in Africa ...

    African Journals Online (AJOL)

    Nanoscale science and nanotechnology education in Africa: importance and ... field with its footing in chemistry, physics, molecular biology and engineering. ... career/business/development opportunities, risks and policy challenges that would ...

  5. Nanoscale structural and chemical analysis of F-implanted enhancement-mode InAlN/GaN heterostructure field effect transistors

    Science.gov (United States)

    Tang, Fengzai; Lee, Kean B.; Guiney, Ivor; Frentrup, Martin; Barnard, Jonathan S.; Divitini, Giorgio; Zaidi, Zaffar H.; Martin, Tomas L.; Bagot, Paul A.; Moody, Michael P.; Humphreys, Colin J.; Houston, Peter A.; Oliver, Rachel A.; Wallis, David J.

    2018-01-01

    We investigate the impact of a fluorine plasma treatment used to obtain enhancement-mode operation on the structure and chemistry at the nanometer and atomic scales of an InAlN/GaN field effect transistor. The fluorine plasma treatment is successful in that enhancement mode operation is achieved with a +2.8 V threshold voltage. However, the InAlN barrier layers are observed to have been damaged by the fluorine treatment with their thickness being reduced by up to 50%. The treatment also led to oxygen incorporation within the InAlN barrier layers. Furthermore, even in the as-grown structure, Ga was unintentionally incorporated during the growth of the InAlN barrier. The impact of both the reduced barrier thickness and the incorporated Ga within the barrier on the transistor properties has been evaluated theoretically and compared to the experimentally determined two-dimensional electron gas density and threshold voltage of the transistor. For devices without fluorine treatment, the two-dimensional electron gas density is better predicted if the quaternary nature of the barrier is taken into account. For the fluorine treated device, not only the changes to the barrier layer thickness and composition, but also the fluorine doping needs to be considered to predict device performance. These studies reveal the factors influencing the performance of these specific transistor structures and highlight the strengths of the applied nanoscale characterisation techniques in revealing information relevant to device performance.

  6. Evolution of nanoscale zero-valent iron (nZVI) in water: Microscopic and spectroscopic evidence on the formation of nano- and micro-structured iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Airong, E-mail: liuairong@tongji.edu.cn; Liu, Jing; Han, Jinhao; Zhang, Wei-xian, E-mail: zhangwx@tongji.edu.cn

    2017-01-15

    Highlights: • A comprehensive study of corrosion products for nZVI under both oxic and anoxic conditions is performed. • Under anoxic conditions, the oxidation products contain a mixture of wustite (FeO), goethite (α-FeOOH) and akaganeite (β-FeOOH). • Under oxic conditions, the final products are mainly crystalline lepidocrocite (γ-FeOOH) with acicular-shaped structures. • Morphological and structural evolution of nZVI under both oxic and anoxic conditions are substantially different. - Abstract: Knowledge on the transformation of nanoscale zero-valent iron (nZVI) in water is essential to predict its surface chemistry including surface charge, colloidal stability and aggregation, reduction and sorption of organic contaminants, heavy metal ions and other pollutants in the environment. In this work, transmission electronic microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy are applied to study the compositional and structural evolution of nZVI under oxic and anoxic conditions. Under anoxic conditions, the core–shell structure of nZVI is well maintained even after 72 h, and the corrosion products usually contain a mixture of wustite (FeO), goethite (α-FeOOH) and akaganeite (β-FeOOH). Under oxic conditions, the core–shell structure quickly collapses to flakes or acicular-shaped structures with crystalline lepidocrocite (γ-FeOOH) as the primary end product. This work provides detailed information and fills an important knowledge gap on the physicochemical characteristics and structural evolution of engineered nanomaterials in the environment.

  7. 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...

  8. A Bioinspired Alginate-Gum Arabic Hydrogel with Micro-/Nanoscale Structures for Controlled Drug Release in Chronic Wound Healing.

    Science.gov (United States)

    Li, Mi; Li, Haichang; Li, Xiangguang; Zhu, Hua; Xu, Zihui; Liu, Lianqing; Ma, Jianjie; Zhang, Mingjun

    2017-07-12

    Biopolymeric hydrogels have drawn increasing research interest in biomaterials due to their tunable physical and chemical properties for both creating bioactive cellular microenvironment and serving as sustainable therapeutic reagents. Inspired by a naturally occurring hydrogel secreted from the carnivorous Sundew plant for trapping insects, here we have developed a bioinspired hydrogel to deliver mitsugumin 53 (MG53), an important protein in cell membrane repair, for chronic wound healing. Both chemical compositions and micro-/nanomorphological properties inherent from the natural Sundew hydrogel were mimicked using sodium alginate and gum arabic with calcium ion-mediated cross-linking. On the basis of atomic force microscopy (AFM) force measurements, an optimal sticky hydrogel scaffold was obtained through orthogonal experimental design. Imaging and mechanical analysis showed the distinct correlation between structural morphology, adhesion characteristics, and mechanical properties of the Sundew-inspired hydrogel. Combined characterization and biochemistry techniques were utilized to uncover the underlying molecular composition involved in the interactions between hydrogel and protein. In vitro drug release experiments confirmed that the Sundew-inspired hydrogel had a biphasic-kinetics release, which can facilitate both fast delivery of MG53 for improving the reepithelization process of the wounds and sustained release of the protein for treating chronic wounds. In vivo experiments showed that the Sundew-inspired hydrogel encapsulating with rhMG53 could facilitate dermal wound healing in mouse model. Together, these studies confirmed that the Sundew-inspired hydrogel has both tunable micro-/nanostructures and physicochemical properties, which enable it as a delivery vehicle for chronic wounding healing. The research may provide a new way to develop biocompatible and tunable biomaterials for sustainable drug release to meet the needs of biological activities.

  9. WE-DE-202-01: Connecting Nanoscale Physics to Initial DNA Damage Through Track Structure Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Schuemann, J. [Massachusetts General Hospital (United States)

    2016-06-15

    Radiation therapy for the treatment of cancer has been established as a highly precise and effective way to eradicate a localized region of diseased tissue. To achieve further significant gains in the therapeutic ratio, we need to move towards biologically optimized treatment planning. To achieve this goal, we need to understand how the radiation-type dependent patterns of induced energy depositions within the cell (physics) connect via molecular, cellular and tissue reactions to treatment outcome such as tumor control and undesirable effects on normal tissue. Several computational biology approaches have been developed connecting physics to biology. Monte Carlo simulations are the most accurate method to calculate physical dose distributions at the nanometer scale, however simulations at the DNA scale are slow and repair processes are generally not simulated. Alternative models that rely on the random formation of individual DNA lesions within one or two turns of the DNA have been shown to reproduce the clusters of DNA lesions, including single strand breaks (SSBs), double strand breaks (DSBs) without the need for detailed track structure simulations. Efficient computational simulations of initial DNA damage induction facilitate computational modeling of DNA repair and other molecular and cellular processes. Mechanistic, multiscale models provide a useful conceptual framework to test biological hypotheses and help connect fundamental information about track structure and dosimetry at the sub-cellular level to dose-response effects on larger scales. In this symposium we will learn about the current state of the art of computational approaches estimating radiation damage at the cellular and sub-cellular scale. How can understanding the physics interactions at the DNA level be used to predict biological outcome? We will discuss if and how such calculations are relevant to advance our understanding of radiation damage and its repair, or, if the underlying biological

  10. WE-DE-202-01: Connecting Nanoscale Physics to Initial DNA Damage Through Track Structure Simulations

    International Nuclear Information System (INIS)

    Schuemann, J.

    2016-01-01

    Radiation therapy for the treatment of cancer has been established as a highly precise and effective way to eradicate a localized region of diseased tissue. To achieve further significant gains in the therapeutic ratio, we need to move towards biologically optimized treatment planning. To achieve this goal, we need to understand how the radiation-type dependent patterns of induced energy depositions within the cell (physics) connect via molecular, cellular and tissue reactions to treatment outcome such as tumor control and undesirable effects on normal tissue. Several computational biology approaches have been developed connecting physics to biology. Monte Carlo simulations are the most accurate method to calculate physical dose distributions at the nanometer scale, however simulations at the DNA scale are slow and repair processes are generally not simulated. Alternative models that rely on the random formation of individual DNA lesions within one or two turns of the DNA have been shown to reproduce the clusters of DNA lesions, including single strand breaks (SSBs), double strand breaks (DSBs) without the need for detailed track structure simulations. Efficient computational simulations of initial DNA damage induction facilitate computational modeling of DNA repair and other molecular and cellular processes. Mechanistic, multiscale models provide a useful conceptual framework to test biological hypotheses and help connect fundamental information about track structure and dosimetry at the sub-cellular level to dose-response effects on larger scales. In this symposium we will learn about the current state of the art of computational approaches estimating radiation damage at the cellular and sub-cellular scale. How can understanding the physics interactions at the DNA level be used to predict biological outcome? We will discuss if and how such calculations are relevant to advance our understanding of radiation damage and its repair, or, if the underlying biological

  11. EXAFS and XANES analysis of oxides at the nanoscale

    Directory of Open Access Journals (Sweden)

    Alexei Kuzmin

    2014-11-01

    Full Text Available Worldwide research activity at the nanoscale is triggering the appearance of new, and frequently surprising, materials properties in which the increasing importance of surface and interface effects plays a fundamental role. This opens further possibilities in the development of new multifunctional materials with tuned physical properties that do not arise together at the bulk scale. Unfortunately, the standard methods currently available for solving the atomic structure of bulk crystals fail for nanomaterials due to nanoscale effects (very small crystallite sizes, large surface-to-volume ratio, near-surface relaxation, local lattice distortions etc.. As a consequence, a critical reexamination of the available local-structure characterization methods is needed. This work discusses the real possibilities and limits of X-ray absorption spectroscopy (XAS analysis at the nanoscale. To this end, the present state of the art for the interpretation of extended X-ray absorption fine structure (EXAFS is described, including an advanced approach based on the use of classical molecular dynamics and its application to nickel oxide nanoparticles. The limits and possibilities of X-ray absorption near-edge spectroscopy (XANES to determine several effects associated with the nanocrystalline nature of materials are discussed in connection with the development of ZnO-based dilute magnetic semiconductors (DMSs and iron oxide nanoparticles.

  12. Nanoscale thermal transport. II. 2003–2012

    OpenAIRE

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2013-01-01

    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 th...

  13. Effect of antimony nano-scale surface-structures on a GaSb/AlAsSb distributed Bragg reflector

    International Nuclear Information System (INIS)

    Husaini, S.; Shima, D.; Ahirwar, P.; Rotter, T. J.; Hains, C. P.; Dang, T.; Bedford, R. G.; Balakrishnan, G.

    2013-01-01

    Effects of antimony crystallization on the surface of GaSb during low temperature molecular beam epitaxy growth are investigated. The geometry of these structures is studied via transmission electron and atomic force microscopies, which show the surface metal forms triangular-shaped, elongated nano-wires with a structured orientation composed entirely of crystalline antimony. By depositing antimony on a GaSb/AlAsSb distributed Bragg reflector, the field is localized within the antimony layer. Polarization dependent transmission measurements are carried out on these nano-structures deposited on a GaSb/AlAsSb distributed Bragg reflector. It is shown that the antimony-based structures at the surface favor transmission of light polarized perpendicular to the wires.

  14. Influence of different aspect ratios on the structural and electrical properties of GaN thin films grown on nanoscale-patterned sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Fang-Wei [Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); Ke, Wen-Cheng, E-mail: wcke@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Cheng, Chun-Hong; Liao, Bo-Wei; Chen, Wei-Kuo [Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan (China)

    2016-07-01

    Highlights: • Nanoscale patterned sapphire substrate was prepared by anodic-aluminum-oxide etching mask. • Influence of aspect ratio of NPSS on structural and electrical properties of GaN films was studied. • Low dislocation density and high carrier mobility of GaN films were grown on high aspect ratio NPSS. - Abstract: This study presents GaN thin films grown on nanoscale-patterned sapphire substrates (NPSSs) with different aspect ratios (ARs) using a homemade metal-organic chemical vapor deposition system. The anodic aluminum oxide (AAO) technique is used to prepare the dry etching mask. The cross-sectional view of the scanning electron microscope image shows that voids exist between the interface of the GaN thin film and the high-AR (i.e. ∼2) NPSS. In contrast, patterns on the low-AR (∼0.7) NPSS are filled full of GaN. The formation of voids on the high-AR NPSS is believed to be due to the enhancement of the lateral growth in the initial growth stage, and the quick-merging GaN thin film blocks the precursors from continuing to supply the bottom of the pattern. The atomic force microscopy images of GaN on bare sapphire show a layer-by-layer surface morphology, which becomes a step-flow surface morphology for GaN on a high-AR NPSS. The edge-type threading dislocation density can be reduced from 7.1 × 10{sup 8} cm{sup −2} for GaN on bare sapphire to 4.9 × 10{sup 8} cm{sup −2} for GaN on a high-AR NPSS. In addition, the carrier mobility increases from 85 cm{sup 2}/Vs for GaN on bare sapphire to 199 cm{sup 2}/Vs for GaN on a high-AR NPSS. However, the increased screw-type threading dislocation density for GaN on a low-AR NPSS is due to the competition of lateral growth on the flat-top patterns and vertical growth on the bottom of the patterns that causes the material quality of the GaN thin film to degenerate. Thus, the experimental results indicate that the AR of the particular patterning of a NPSS plays a crucial role in achieving GaN thin film with

  15. Nanoscale characterization of local structures and defects in photonic crystals using synchrotron-based transmission soft X-ray microscopy

    Science.gov (United States)

    Nho, Hyun Woo; Kalegowda, Yogesh; Shin, Hyun-Joon; Yoon, Tae Hyun

    2016-01-01

    For the structural characterization of the polystyrene (PS)-based photonic crystals (PCs), fast and direct imaging capabilities of full field transmission X-ray microscopy (TXM) were demonstrated at soft X-ray energy. PS-based PCs were prepared on an O2-plasma treated Si3N4 window and their local structures and defects were investigated using this label-free TXM technique with an image acquisition speed of ~10 sec/frame and marginal radiation damage. Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components. Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated. This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties. PMID:27087141

  16. Local and Nanoscale Structure and Speciation in the PuO2+x-y(OH)2y ·zH2O System

    International Nuclear Information System (INIS)

    Conradson, Steven D.; Begg, Bruce D.; Clark, David L.; Den Auwer, Christophe J.; Ding, Mei; Dorhout, Peter K.; Espinosa-Faller, Francisco J.; Gordon, Pamela L.; Haire, Richard G.; Hess, Nancy J.; Hess, Ryan F.; Keogh, D. Webster; Morales, Luis A.; Neu, Mary P.; Paviet-Hartmann, Patricia; Runde, Wolfgang; Tait, C DREW; Veirs, D. Kirk; Villella, Phillip M.

    2004-01-01

    Pu L3 X-ray absorption fine structure spectra from 24 samples of PuO 2+x (and two related Pu substituted oxides), prepared by a variety of methods, demonstrate that (1) although the Pu sublattice remains the ordered part of the Pu distribution, the nearest-neighbor O atoms even at x = 0 are found in a multisite distribution with Pu-O distances consistent with the stable incorporation of OH - (and possibly H 2 O and H + ) into the PuO 2 lattice; (2) the excess O from oxidation is found at Pu-O distances 2 + moieties that are aperiodically distributed through the lattice; and (4) the collective interactions between these defect sites most likely cause them to cluster so as give nanoscale heterogeneity in the form of domains that may have unusual reactivity, observed as sequential oxidation by H 2 O at ambient conditions. The most accurate description of PuO 2 is therefore actually PuO 2+x-y (OH) 2y · zH 2 O, with pure, ordered, homogeneous PuO 2 attained only when H 2 O is rigorously excluded and the O activity is relatively low

  17. Naphtho[2,1-b:3,4-b']dithiophene-based bulk heterojunction solar cells: how molecular structure influences nanoscale morphology and photovoltaic properties.

    Science.gov (United States)

    Kim, Yu Jin; Cheon, Ye Rim; Back, Jang Yeol; Kim, Yun-Hi; Chung, Dae Sung; Park, Chan Eon

    2014-11-10

    Organic bulk heterojunction photovoltaic devices based on a series of three naphtho[2,1-b:3,4-b']dithiophene (NDT) derivatives blended with phenyl-C71-butyric acid methyl ester were studied. These three derivatives, which have NDT units with various thiophene-chain lengths, were employed as the donor polymers. The influence of their molecular structures on the correlation between their solar-cell performances and their degree of crystallization was assessed. The grazing-incidence angle X-ray diffraction and atomic force microscopy results showed that the three derivatives exhibit three distinct nanoscale morphologies. We correlated these morphologies with the device physics by determining the J-V characteristics and the hole and electron mobilities of the devices. On the basis of our results, we propose new rules for the design of future generations of NDT-based polymers for use in bulk heterojunction solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Nanoscale Ionic Liquids

    Science.gov (United States)

    2006-11-01

    Technical Report 11 December 2005 - 30 November 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoscale Ionic Liquids 5b. GRANT NUMBER FA9550-06-1-0012...Title: Nanoscale Ionic Liquids Principal Investigator: Emmanuel P. Giannelis Address: Materials Science and Engineering, Bard Hall, Cornell University...based fluids exhibit high ionic conductivity. The NFs are typically synthesized by grafting a charged, oligomeric corona onto the nanoparticle cores

  19. 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.

  20. Systems engineering at the nanoscale

    Science.gov (United States)

    Benkoski, Jason J.; Breidenich, Jennifer L.; Wei, Michael C.; Clatterbaughi, Guy V.; Keng, Pei Yuin; Pyun, Jeffrey

    2012-06-01

    Nanomaterials have provided some of the greatest leaps in technology over the past twenty years, but their relatively early stage of maturity presents challenges for their incorporation into engineered systems. Perhaps even more challenging is the fact that the underlying physics at the nanoscale often run counter to our physical intuition. The current state of nanotechnology today includes nanoscale materials and devices developed to function as components of systems, as well as theoretical visions for "nanosystems," which are systems in which all components are based on nanotechnology. Although examples will be given to show that nanomaterials have indeed matured into applications in medical, space, and military systems, no complete nanosystem has yet been realized. This discussion will therefore focus on systems in which nanotechnology plays a central role. Using self-assembled magnetic artificial cilia as an example, we will discuss how systems engineering concepts apply to nanotechnology.

  1. Effect of preparation conditions on fractal structure and phase transformations in the synthesis of nanoscale M-type barium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Pashkova, E.V. [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine); Solovyova, E.D., E-mail: solovyovak@mail.ru [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine); Kotenko, I.E., E-mail: Hab2420@yahoo.com [National Technical University of Ukraine ' KPI' , Pr. Pobedy, 37, Kyiv-57 (Ukraine); Kolodiazhnyi, T.V., E-mail: kolodiazhnyi.taras@nims.go.jp [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Belous, A.G., E-mail: belous@ionc.kar.net [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine)

    2011-10-15

    The conditions of the synthesis of carbonate-hydroxide precursors (pH of FeOOH precipitation and heat treatment regimes) were studied in terms of their effect on the fractal structure and physical-chemical properties of precursors. Phase transformations which occur during the synthesis of nanosize M-type barium hexaferrite (BHF) were studied as well. The first structural level of precursors' aggregation for mass fractals, the correlation between fractal dimension and precursors' activity during the synthesis of BHF were determined. Synthesis parameters for the precursors with the optimal fractal structure were determined. These data permit an enhancement of the filtration coefficient of the precipitates by a factor of 4-5, obtaining substantial decrease in the temperature required for synthesis of a single-phase BHF, and monodispersed plate-like nanoparticles (60 nm diameter) with the shape anisotropy and good magnetic characteristics (saturation magnetization (M{sub s})=68,7 emu/g and coercitivity (H{sub c})=5440 Oe). - Highlights: > The nanosize M-type BHF obtained by precipitation of hydroxicarbonates technique. > Optimal fractal structure of a precursor for nanosize M-type BHF has been determined. > The precursor precipitated at pH 4.3 allows getting monodisperse particles of BHF.

  2. Uncovering nanoscale electromechanical heterogeneity in the subfibrillar structure of collagen fibrils responsible for the piezoelectricity of bone.

    Science.gov (United States)

    Minary-Jolandan, Majid; Yu, Min-Feng

    2009-07-28

    Understanding piezoelectricity, the linear electromechanical transduction, in bone and tendon and its potential role in mechanoelectric transduction leading to their growth and remodeling remains a challenging subject. With high-resolution piezoresponse force microscopy, we probed piezoelectric behavior in relevant biological samples at different scale levels: from the subfibrillar structures of single isolated collagen fibrils to bone. We revealed that, beyond the general understanding of collagen fibril being a piezoelectric material, there existed an intrinsic piezoelectric heterogeneity within a collagen fibril coinciding with the periodic variation of its gap and overlap regions. This piezoelectric heterogeneity persisted even for the collagen fibrils embedded in bone, bringing about new implications for its possible roles in structural formation and remodeling of bone.

  3. Electronic structure of nanoscale Cu/Pt alloys: A combined X-ray diffraction and X-ray absorption investigations

    International Nuclear Information System (INIS)

    Chen Xing; Chu Wangsheng; Cai Quan; Xia Dingguo; Wu Zhonghua; Wu Ziyu

    2006-01-01

    PVP-protected Cu/Pt clusters were prepared by glycol/water reduction method and characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD) and absorption spectra. TEM and XRD analysis show that the Cu/Pt clusters with different molar ratio have fcc structure with particle size of about 4 nm, while the lattice parameters in these clusters reduce with increasing Cu concentration. From the X-ray absorption near edge structure (XANES) at Cu-K edge and Pt-L 2,3 edge, we demonstrate that the d-electronic states of Cu and Pt are affected by the local environment as a function of Cu/Pt molar ratio. With increasing Cu concentration, Pt loses a fraction of 5d electrons and the hybridization between p- and d-states at Cu sites is enhanced

  4. Electronic structure of nanoscale Cu/Pt alloys: A combined X-ray diffraction and X-ray absorption investigations

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xing [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Graduate School of the Chinese Academy of Sciences, 100864 Beijing (China); Chu Wangsheng [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); University of Science and Technology of China, Hefei, 230036 (China); Cai Quan [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Graduate School of the Chinese Academy of Sciences, 100864 Beijing (China); Xia Dingguo [College of Environmental and Energy Engineering, Beijing University of Technology, 100022 Beijing (China); Wu Zhonghua [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Wu Ziyu [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China) and National Center for Nanoscience and Technology (China)]. E-mail: wuzy@ihep.ac.cn

    2006-11-15

    PVP-protected Cu/Pt clusters were prepared by glycol/water reduction method and characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD) and absorption spectra. TEM and XRD analysis show that the Cu/Pt clusters with different molar ratio have fcc structure with particle size of about 4 nm, while the lattice parameters in these clusters reduce with increasing Cu concentration. From the X-ray absorption near edge structure (XANES) at Cu-K edge and Pt-L{sub 2,3} edge, we demonstrate that the d-electronic states of Cu and Pt are affected by the local environment as a function of Cu/Pt molar ratio. With increasing Cu concentration, Pt loses a fraction of 5d electrons and the hybridization between p- and d-states at Cu sites is enhanced.

  5. Design of a Nanoscale, CMOS-Integrable, Thermal-Guiding Structure for Boolean-Logic and Neuromorphic Computation.

    Science.gov (United States)

    Loke, Desmond; Skelton, Jonathan M; Chong, Tow-Chong; Elliott, Stephen R

    2016-12-21

    One of the requirements for achieving faster CMOS electronics is to mitigate the unacceptably large chip areas required to steer heat away from or, more recently, toward the critical nodes of state-of-the-art devices. Thermal-guiding (TG) structures can efficiently direct heat by "meta-materials" engineering; however, some key aspects of the behavior of these systems are not fully understood. Here, we demonstrate control of the thermal-diffusion properties of TG structures by using nanometer-scale, CMOS-integrable, graphene-on-silica stacked materials through finite-element-methods simulations. It has been shown that it is possible to implement novel, controllable, thermally based Boolean-logic and spike-timing-dependent plasticity operations for advanced (neuromorphic) computing applications using such thermal-guide architectures.

  6. Wire-in-tube structure fabricated by single capillary electrospinning via nanoscale Kirkendall effect: the case of nickel-zinc ferrite.

    Science.gov (United States)

    Fu, Jiecai; Zhang, Junli; Peng, Yong; Zhao, Changhui; He, Yongmin; Zhang, Zhenxing; Pan, Xiaojun; Mellors, Nigel J; Xie, Erqing

    2013-12-21

    Wire-in-tube structures have previously been prepared using an electrospinning method by means of tuning hydrolysis/alcoholysis of a precursor solution. Nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4) nanowire-in-nanotubes have been prepared as a demonstration. The detailed nanoscale characterization, formation process and magnetic properties of Ni0.5Zn0.5Fe2O4 nanowire-in-nanotubes has been studied comprehensively. The average diameters of the outer tubes and inner wires of Ni0.5Zn0.5Fe2O4 nanowire-in-nanotubes are around 120 nm and 42 nm, respectively. Each fully calcined individual nanowire-in-nanotube, either the outer-tube or the inner-wire, is composed of Ni0.5Zn0.5Fe2O4 monocrystallites stacked along the longitudinal direction with random orientation. The process of calcining electrospun polymer composite nanofibres can be viewed as a morphologically template nucleation and precursor diffusion process. This allows the nitrates precursor to diffuse toward the surface of the nanofibres while the oxides (decomposed from hydroxides and nitrates) products diffuse to the core region of the nanofibres; the amorphous nanofibres transforming thereby into crystalline nanowire-in-nanotubes. In addition, the magnetic properties of the Ni0.5Zn0.5Fe2O4 nanowire-in-nanotubes were also examined. It is believed that this nanowire-in-nanotube (sometimes called core-shell) structure, with its uniform size and well-controlled orientation of the long nanowire-in-nanotubes, is particularly attractive for use in the field of nano-fluidic devices and nano-energy harvesting devices.

  7. Accelerator structure development for NLC

    International Nuclear Information System (INIS)

    Hoag, H.A.; Deruyter, H.; Pearson, C.; Ruth, R.D.; Wang, J.W.; Schaefer, J.

    1993-04-01

    In the program of work directed towards the development of an X-Band Next Linear Collider accelerator structure, two different test accelerator sections have been completed, and a third is being fabricated. The first is a simple 30-cell constant-impedance section in which no special attention was given to surface finish, pumping, and alignment. The second is an 86-cell section in which the cells were precision diamond-turned by Texas Instruments Inc. The structure has internal water-cooling and vacuum pumping manifolds. Some design details are given for the third section, which is a 206-cell structure with cavities dimensioned to give a Gaussian distribution of dipole mode frequencies. It has conventional-machining surface finishes and external water and pumping manifolds. Component design, fabrication, and assembly brazing are described for the first two experimental sections

  8. Super-Resolution Molecular and Functional Imaging of Nanoscale Architectures in Life and Materials Science

    KAUST Repository

    Habuchi, Satoshi

    2014-06-12

    Super-resolution (SR) fluorescence microscopy has been revolutionizing the way in which we investigate the structures, dynamics, and functions of a wide range of nanoscale systems. In this review, I describe the current state of various SR fluorescence microscopy techniques along with the latest developments of fluorophores and labeling for the SR microscopy. I discuss the applications of SR microscopy in the fields of life science and materials science with a special emphasis on quantitative molecular imaging and nanoscale functional imaging. These studies open new opportunities for unraveling the physical, chemical, and optical properties of a wide range of nanoscale architectures together with their nanostructures and will enable the development of new (bio-)nanotechnology.

  9. Spin-dependent hot electron transport and nano-scale magnetic imaging of metal/Si structures

    International Nuclear Information System (INIS)

    Kaidatzis, A.

    2008-10-01

    In this work, we experimentally study spin-dependent hot electron transport through metallic multilayers (ML), containing single magnetic layers or 'spin-valve' (SV) tri layers. For this purpose, we have set up a ballistic electron emission microscope (BEEM), a three terminal extension of scanning tunnelling microscopy on metal/semiconductor structures. The implementation of the BEEM requirements into the sample fabrication is described in detail. Using BEEM, the hot electron transmission through the ML's was systematically measured in the energy range 1-2 eV above the Fermi level. By varying the magnetic layer thickness, the spin-dependent hot electron attenuation lengths were deduced. For the materials studied (Co and NiFe), they were compared to calculations and other determinations in the literature. For sub-monolayer thickness, a non uniform morphology was observed, with large transmission variations over sub-nano-metric distances. This effect is not yet fully understood. In the imaging mode, the magnetic configurations of SV's were studied under field, focusing on 360 degrees domain walls in Co layers. The effects of the applied field intensity and direction on the DW structure were studied. The results were compared quantitatively to micro-magnetic calculations, with an excellent agreement. From this, it can be shown that the BEEM magnetic resolution is better than 50 nm. (author)

  10. Label-free nanoscale characterization of red blood cell structure and dynamics using single-shot transport of intensity equation

    Science.gov (United States)

    Poola, Praveen Kumar; John, Renu

    2017-10-01

    We report the results of characterization of red blood cell (RBC) structure and its dynamics with nanometric sensitivity using transport of intensity equation microscopy (TIEM). Conventional transport of intensity technique requires three intensity images and hence is not suitable for studying real-time dynamics of live biological samples. However, assuming the sample to be homogeneous, phase retrieval using transport of intensity equation has been demonstrated with single defocused measurement with x-rays. We adopt this technique for quantitative phase light microscopy of homogenous cells like RBCs. The main merits of this technique are its simplicity, cost-effectiveness, and ease of implementation on a conventional microscope. The phase information can be easily merged with regular bright-field and fluorescence images to provide multidimensional (three-dimensional spatial and temporal) information without any extra complexity in the setup. The phase measurement from the TIEM has been characterized using polymeric microbeads and the noise stability of the system has been analyzed. We explore the structure and real-time dynamics of RBCs and the subdomain membrane fluctuations using this technique.

  11. 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.

  12. Nanoscale biophysics of the cell

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2018-01-01

    Macroscopic cellular structures and functions are generally investigated using biological and biochemical approaches. But these methods are no longer adequate when one needs to penetrate deep into the small-scale structures and understand their functions. The cell is found to hold various physical structures, molecular machines, and processes that require physical and mathematical approaches to understand and indeed manipulate them. Disorders in general cellular compartments, perturbations in single molecular structures, drug distribution therein, and target specific drug-binding, etc. are mostly physical phenomena. This book will show how biophysics has revolutionized our way of addressing the science and technology of nanoscale structures of cells, and also describes the potential for manipulating the events that occur in them.

  13. Nanoscale surface characterization using laser interference microscopy

    Science.gov (United States)

    Ignatyev, Pavel S.; Skrynnik, Andrey A.; Melnik, Yury A.

    2018-03-01

    Nanoscale surface characterization is one of the most significant parts of modern materials development and application. The modern microscopes are expensive and complicated tools, and its use for industrial tasks is limited due to laborious sample preparation, measurement procedures, and low operation speed. The laser modulation interference microscopy method (MIM) for real-time quantitative and qualitative analysis of glass, metals, ceramics, and various coatings has a spatial resolution of 0.1 nm for vertical and up to 100 nm for lateral. It is proposed as an alternative to traditional scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods. It is demonstrated that in the cases of roughness metrology for super smooth (Ra >1 nm) surfaces the application of a laser interference microscopy techniques is more optimal than conventional SEM and AFM. The comparison of semiconductor test structure for lateral dimensions measurements obtained with SEM and AFM and white light interferometer also demonstrates the advantages of MIM technique.

  14. On The Role of Wetting, Structure Width, and Flow Characteristics in Polymer Replication on Micro- and Nanoscale

    DEFF Research Database (Denmark)

    Rytka, Christian; Opara, Nadia; Andersen, Nis Korsgaard

    2016-01-01

    The replication of functional polymeric micro- and nanostructures requires a deep understanding of material and process interrelations. In this investigation the dewetting potential of a polymer is proposed as a simple rationale for estimation of the replicability of functional micro- and nanostr......The replication of functional polymeric micro- and nanostructures requires a deep understanding of material and process interrelations. In this investigation the dewetting potential of a polymer is proposed as a simple rationale for estimation of the replicability of functional micro......- and nanostructures by injection molding. The dewetting potential of a polymer is determined by integrating the spreading coefficient over the range from melt temperature to no-flow temperature. From all polymers tested, the lowest dewetting potential is calculated for PP and the highest for polymethylmethacrylate....... The dewetting potential correlates well with the replicated height of four different structures covering both the micro- and the nanorange on two different surfaces (brass and fluorocarbon modified nickel) and polymers with different spreading coefficients. It is clearly shown that a lower dewetting potential...

  15. Spatially resolved investigation of competing nanocluster emission in quantum-disks-in-nanowires structure characterized by nanoscale cathodoluminescence

    KAUST Repository

    Prabaswara, Aditya; Stowe, David J.; Janjua, Bilal; Ng, Tien Khee; Anjum, Dalaver H.; Longo, Paolo; Zhao, Chao; Elafandy, Rami T.; Li, Xiaohang; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

    2017-01-01

    We report on the study and characterization of nanoclusters-related recombination centers within quantum-disks-in-nanowires heterostructure by utilizing microphotoluminescence (mu-PL) and cathodoluminescence scanning transmission electron microscopy (CL-STEM). mu-PL measurement shows that the nanoclusters-related recombination center exhibits different temperature-dependent characteristics compared with the surrounding InGaN quantum-disksrelated recombination center. CL-STEM measurements reveal that these recombination centers mainly arise from irregularities within the quantum disks, with a strong, spatially localized emission when measured at low temperature. The spectra obtained from both CL-STEM and mu-PL correlate well with each other. Our work sheds light on the optical and structural properties of simultaneously coexisting recombination centers within nanowires heterostructures. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

  16. Spatially resolved investigation of competing nanocluster emission in quantum-disks-in-nanowires structure characterized by nanoscale cathodoluminescence

    KAUST Repository

    Prabaswara, Aditya

    2017-06-30

    We report on the study and characterization of nanoclusters-related recombination centers within quantum-disks-in-nanowires heterostructure by utilizing microphotoluminescence (mu-PL) and cathodoluminescence scanning transmission electron microscopy (CL-STEM). mu-PL measurement shows that the nanoclusters-related recombination center exhibits different temperature-dependent characteristics compared with the surrounding InGaN quantum-disksrelated recombination center. CL-STEM measurements reveal that these recombination centers mainly arise from irregularities within the quantum disks, with a strong, spatially localized emission when measured at low temperature. The spectra obtained from both CL-STEM and mu-PL correlate well with each other. Our work sheds light on the optical and structural properties of simultaneously coexisting recombination centers within nanowires heterostructures. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

  17. Combining in situ transmission electron microscopy irradiation experiments with cluster dynamics modeling to study nanoscale defect agglomeration in structural metals

    International Nuclear Information System (INIS)

    Xu Donghua; Wirth, Brian D.; Li Meimei; Kirk, Marquis A.

    2012-01-01

    We present a combinatorial approach that integrates state-of-the-art transmission electron microscopy (TEM) in situ irradiation experiments and high-performance computing techniques to study irradiation defect dynamics in metals. Here, we have studied the evolution of visible defect clusters in nanometer-thick molybdenum foils under 1 MeV krypton ion irradiation at 80 °C through both cluster dynamics modeling and in situ TEM experiments. The experimental details are reported elsewhere; we focus here on the details of model construction and comparing the model with the experiments. The model incorporates continuous production of point defects and/or small clusters, and the accompanying interactions, which include clustering, recombination and loss to the surfaces that result from the diffusion of the mobile defects. To account for the strong surface effect in thin TEM foils, the model includes one-dimensional spatial dependence along the foil depth, and explicitly treats the surfaces as black sinks. The rich amount of data (cluster number density and size distribution at a variety of foil thickness, irradiation dose and dose rate) offered by the advanced in situ experiments has allowed close comparisons with computer modeling and permitted significant validation and optimization of the model in terms of both physical model construct (damage production mode, identities of mobile defects) and parameterization (diffusivities of mobile defects). The optimized model exhibits good qualitative and quantitative agreement with the in situ TEM experiments. The combinatorial approach is expected to bring a unique opportunity for the study of radiation damage in structural materials.

  18. Nanoscale phase-change materials and devices

    International Nuclear Information System (INIS)

    Zheng, Qinghui; Wang, Yuxi; Zhu, Jia

    2017-01-01

    Phase-change materials (PCMs) that can reversibly transit between crystalline and amorphous phases have been widely used for data-storage and other functional devices. As PCMs scale down to nanoscale, the properties and transition procedures can vary, bringing both challenges and opportunities in scalability. This article describes the physical structures, properties and applications of nanoscale phase-change materials and devices. The limitations and performance of scaling properties in phase-change materials and the recent progress and challenges in phase-change devices are presented. At the end, some emerging applications related to phase-change materials are also introduced. (topical review)

  19. Nanoscale phase-change materials and devices

    Science.gov (United States)

    Zheng, Qinghui; Wang, Yuxi; Zhu, Jia

    2017-06-01

    Phase-change materials (PCMs) that can reversibly transit between crystalline and amorphous phases have been widely used for data-storage and other functional devices. As PCMs scale down to nanoscale, the properties and transition procedures can vary, bringing both challenges and opportunities in scalability. This article describes the physical structures, properties and applications of nanoscale phase-change materials and devices. The limitations and performance of scaling properties in phase-change materials and the recent progress and challenges in phase-change devices are presented. At the end, some emerging applications related to phase-change materials are also introduced.

  20. Development of annular coupled structure

    International Nuclear Information System (INIS)

    Kageyama, T.; Morozumi, Y.; Yoshino, K.; Yamazaki, Y.

    1992-01-01

    A π/2-mode standing-wave linac of an Annular Coupled Structure (ACS) has been developed for the 1-GeV proton linac of the Japanese Hadron Project (JHP). This ACS has four coupling slots between accelerating and coupling cells in order to overcome difficulties in putting the ACS to practical use. Two prototypes of a four-slot ACS (f = 1296 MHz, β = v/c = 0.8) have been constructed and tested: one with a staggered slot-orientation from cell to cell; and the other with a uniform one. The staggered configuration gives a larger coupling constant and a larger shunt impedance than the uniform one with the same size of coupling slot. Both models have been conditioned up to the design input RF power. The four-slot ACS gives a distortion-free accelerating field around the beam axis, while a Side-Coupled Structure cavity gives an accelerating field mixed with a TE111-like mode. (Author) 7 figs., 2 tabs., 9 refs

  1. Volume changes at macro- and nano-scale in epoxy resins studied by PALS and PVT experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Somoza, A. [IFIMAT-UNCentro, Pinto 399, B7000GHG Tandil (Argentina) and CICPBA, Pinto 399, B7000GHG Tandil (Argentina)]. E-mail: asomoza@exa.unicen.edu.ar; Salgueiro, W. [IFIMAT-UNCentro, Pinto 399, B7000GHG Tandil (Argentina); Goyanes, S. [LPMPyMC, Depto. de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Ramos, J. [Materials and Technology Group, Departamento de Ingenieria Quimica y M. Ambiente, Escuela University Politecnica, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pz. Europa 1, 20018 Donostia/San Sebastian (Spain); Mondragon, I. [Materials and Technology Group, Departamento de Ingenieria Quimica y M. Ambiente, Escuela University Politecnica, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pz. Europa 1, 20018 Donostia/San Sebastian (Spain)

    2007-02-15

    A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with selected aminic hardeners at different pre-cure temperatures is presented. Free- and macroscopic specific-volumes were measured by PALS and pressure-volume-temperature techniques, respectively. An analysis of the relation existing between macro- and nano-scales of the thermosetting networks developed by the different chemical structures is shown. The result obtained indicates that the structure of the hardeners governs the packing of the molecular chains of the epoxy network.

  2. Bulk nanoscale materials in steel products

    International Nuclear Information System (INIS)

    Chehab, B; Wang, X; Masse, J-P; Zurob, H; Embury, D; Bouaziz, O

    2010-01-01

    Although a number of nanoscale metallic materials exhibit interesting mechanical properties the fabrication paths are often complex and difficult to apply to bulk structural materials. However a number of steels which exhibit combinations of plasticity and phase transitions can be deformed to produce ultra high strength levels in the range 1 to 3 GPa. The resultant high stored energy and complex microstructures allow new nanoscale structures to be produced by combinations of recovery and recrystallisation. The resultant structures exhibit totally new combinations of strength and ductility to be achieved. In specific cases this also enables both the nature of the grain boundary structure and the spatial variation in structure to be controlled. In this presentation both the detailed microstructural features and their relation to the strength, work-hardening capacity and ductility will be discussed for a number of martensitic and austenitic steels.

  3. Structure and tensile properties of Fe-Cr model alloy strengthened by nano-scale NbC particles derived from controlled crystallization of Nb-rich clusters

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Lei [College of Materials and Chemical Engineering, Three Gorges University, Yichang 443002 (China); Guo, Qianying [State Key Lab of Hydraulic Engineering Simulation and Safety, School of Material Science and Engineering, Tianjin University, Tianjin 300354 (China); Liu, Yongchang, E-mail: licmtju@163.com [State Key Lab of Hydraulic Engineering Simulation and Safety, School of Material Science and Engineering, Tianjin University, Tianjin 300354 (China); Yu, Liming; Li, Huijun [State Key Lab of Hydraulic Engineering Simulation and Safety, School of Material Science and Engineering, Tianjin University, Tianjin 300354 (China)

    2016-09-30

    This article describes the microstructural evolution and tensile properties of Fe-Cr model alloy strengthened by nano-scale NbC particles. According to the results obtained from X-ray diffraction and transmission electron microscope with Energy Dispersive Spectrometer, the bcc ultrafine grains and the disordered phase of Nb-rich nano-clusters were observed in the milled powders. The hot pressing (HP) resulted in a nearly equiaxed ferritic grains and dispersed nano-scale NbC (~8 nm) particles. The microstructure studies reveal that the formation of NbC nanoparticles is composed of nucleation and growth of the Nb-rich nano-clusters involving diffusion of their component. At room temperature the material exhibits an ultimate tensile strength of 700 MPa, yield strength of 650 MPa, and total elongation of 11.7 pct. The fracture surface studies reveal that a typical ductile fracture mode has occurred during tensile test.

  4. 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

  5. The synthesis and properties of nanoscale ionic materials

    KAUST Repository

    Rodriguez, Robert Salgado; Herrer, Rafael; Bourlinos, Athanasios B.; Li, Ruipeng; Amassian, Aram; Archer, Lynden A.; Giannelis, Emmanuel P.

    2010-01-01

    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

  6. Quantum dynamics in nanoscale magnets in dissipative environments

    NARCIS (Netherlands)

    Miyashita, S; Saito, K; Kobayashi, H.; de Raedt, H.A.

    2000-01-01

    In discrete energy structure of nanoscale magnets, nonadiabatic transitions at avoided level crossings lead to fundamental processes of dynamics of magnetizations. The thermal environment causes dissipative effects on these processes. In this paper we review the features of the nonadiabatic

  7. 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...

  8. 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.

  9. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.; Moganty, Surya S.; Archer, Lynden A.

    2010-01-01

    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.

  10. Soil Retaining Structures : Development of models for structural analysis

    NARCIS (Netherlands)

    Bakker, K.J.

    2000-01-01

    The topic of this thesis is the development of models for the structural analysis of soil retaining structures. The soil retaining structures being looked at are; block revetments, flexible retaining walls and bored tunnels in soft soil. Within this context typical structural behavior of these

  11. 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

  12. 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.

  13. Nanoscale Synthesis and Characterization Laboratory Annual Report 2005

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, A V; Lesuer, D R

    2006-01-03

    The Nanoscale Synthesis and Characterization Laboratory's (NSCL) primary mission is to create and advance interdisciplinary research and development opportunities in nanoscience and technology. The initial emphasis of the NSCL has been on development of scientific solutions in support of target fabrication for the NIF laser and other stockpile stewardship experimental platforms. Particular emphasis has been placed on the design and development of innovative new materials and structures for use in these targets. Projects range from the development of new high strength nanocrystalline alloys to graded density materials to high Z nanoporous structures. The NSCL also has a mission to recruit and train personnel for Lab programs such as the National Ignition Facility (NIF), Defense and Nuclear Technologies (DNT), and Nonproliferation, Arms control and International security (NAI). The NSCL continues to attract talented scientists to the Laboratory.

  14. Traceable nanoscale measurement at NML-SIRIM

    International Nuclear Information System (INIS)

    Dahlan, Ahmad M.; Abdul Hapip, A. I.

    2012-01-01

    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.

  15. Traceable nanoscale measurement at NML-SIRIM

    Science.gov (United States)

    Dahlan, Ahmad M.; Abdul Hapip, A. I.

    2012-06-01

    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.

  16. 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.

  17. Adhesion and proliferation of OCT-1 osteoblast-like cells on micro- and nano-scale topography structured poly(L-lactide).

    Science.gov (United States)

    Wan, Yuqing; Wang, Yong; Liu, Zhimin; Qu, Xue; Han, Buxing; Bei, Jianzhong; Wang, Shenguo

    2005-07-01

    The impact of the surface topography of polylactone-type polymer on cell adhesion was to be concerned because the micro-scale texture of a surface can provide a significant effect on the adhesion behavior of cells on the surface. Especially for the application of tissue engineering scaffold, the pore size could have an influence on cell in-growth and subsequent proliferation. Micro-fabrication technology was used to generate specific topography to investigate the relationship between the cells and surface. In this study the pits-patterned surfaces of polystyrene (PS) film with diameters 2.2 and 0.45 microm were prepared by phase-separation, and the corresponding scale islands-patterned PLLA surface was prepared by a molding technique using the pits-patterned PS as a template. The adhesion and proliferation behavior of OCT-1 osteoblast-like cells morphology on the pits- and islands-patterned surface were characterized by SEM observation, cell attachment efficiency measurement and MTT assay. The results showed that the cell adhesion could be enhanced on PLLA and PS surface with nano-scale and micro-scale roughness compared to the smooth surfaces of the PLLA and PS. The OCT-1 osteoblast-like cells could grow along the surface with two different size islands of PLLA and grow inside the micro-scale pits of the PS. However, the proliferation of cells on the micro- and nano-scale patterned surface has not been enhanced compared with the controlled smooth surface.

  18. Nanoscale hotspots due to nonequilibrium thermal transport

    International Nuclear Information System (INIS)

    Sinha, Sanjiv; Goodson, Kenneth E.

    2004-01-01

    Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal

  19. Neuromorphic computing with nanoscale spintronic oscillators.

    Science.gov (United States)

    Torrejon, Jacob; Riou, Mathieu; Araujo, Flavio Abreu; Tsunegi, Sumito; Khalsa, Guru; Querlioz, Damien; Bortolotti, Paolo; Cros, Vincent; Yakushiji, Kay; Fukushima, Akio; Kubota, Hitoshi; Yuasa, Shinji; Stiles, Mark D; Grollier, Julie

    2017-07-26

    Neurons in the brain behave as nonlinear oscillators, which develop rhythmic activity and interact to process information. Taking inspiration from this behaviour to realize high-density, low-power neuromorphic computing will require very large numbers of nanoscale nonlinear oscillators. A simple estimation indicates that to fit 10 8 oscillators organized in a two-dimensional array inside a chip the size of a thumb, the lateral dimension of each oscillator must be smaller than one micrometre. However, nanoscale devices tend to be noisy and to lack the stability that is required to process data in a reliable way. For this reason, despite multiple theoretical proposals and several candidates, including memristive and superconducting oscillators, a proof of concept of neuromorphic computing using nanoscale oscillators has yet to be demonstrated. Here we show experimentally that a nanoscale spintronic oscillator (a magnetic tunnel junction) can be used to achieve spoken-digit recognition with an accuracy similar to that of state-of-the-art neural networks. We also determine the regime of magnetization dynamics that leads to the greatest performance. These results, combined with the ability of the spintronic oscillators to interact with each other, and their long lifetime and low energy consumption, open up a path to fast, parallel, on-chip computation based on networks of oscillators.

  20. Nanoscale thermal transport: Theoretical method and application

    Science.gov (United States)

    Zeng, Yu-Jia; Liu, Yue-Yang; Zhou, Wu-Xing; Chen, Ke-Qiu

    2018-03-01

    With the size reduction of nanoscale electronic devices, the heat generated by the unit area in integrated circuits will be increasing exponentially, and consequently the thermal management in these devices is a very important issue. In addition, the heat generated by the electronic devices mostly diffuses to the air in the form of waste heat, which makes the thermoelectric energy conversion also an important issue for nowadays. In recent years, the thermal transport properties in nanoscale systems have attracted increasing attention in both experiments and theoretical calculations. In this review, we will discuss various theoretical simulation methods for investigating thermal transport properties and take a glance at several interesting thermal transport phenomena in nanoscale systems. Our emphasizes will lie on the advantage and limitation of calculational method, and the application of nanoscale thermal transport and thermoelectric property. Project supported by the Nation Key Research and Development Program of China (Grant No. 2017YFB0701602) and the National Natural Science Foundation of China (Grant No. 11674092).

  1. 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.

  2. Development of an optimum end-effector with a nano-scale uneven surface for non-adhesion cell manipulation using a micro-manipulator

    International Nuclear Information System (INIS)

    Horade, M; Kojima, M; Kamiyama, K; Kurata, T; Mae, Y; Arai, T

    2015-01-01

    In order to realize effective micro-manipulation using a micro-manipulator system, an optimum end-effector is proposed. Cell-manipulation experiments using mouse fibroblast cells are conducted, and the usability of the proposed end-effector is confirmed. A key advantage of the micro-manipulator is high-accuracy, high-speed 3D micro- and nano-scale positioning. Micro-manipulation has often been used in research involving biological cells. However, there are two important concerns with the micro-manipulator system: gripping efficiency and the release of gripped objects. When it is not possible to grip a micro-object, such as a cell, near its center, the object may be dropped during manipulation. Since the acquisition of exact position information for a micro-object in the vertical direction is difficult using a microscope, the gripping efficiency of the end-effector should be improved. Therefore, technical skill or operational support is required. Since, on the micro-scale, surface forces such as the adsorption force are greater than body forces, such as the gravitational force, the adhesion force between the end-effector and the object is strong. Therefore, manipulation techniques without adhesion are required for placed an object at an arbitrary position. In the present study, we consider direct physical contact between the end-effector and objects. First, the design and materials of the end-effector for micro-scale manipulation were optimized, and an end-effector with an optimum shape to increase the grip force was fabricated. Second, the surface of the end-effector tip was made uneven, and the adhesion force from increasing on the micro-scale was prevented. When an end-effector with an uneven surface was used, release without adhesion was successful 85.0% of the time. On the other hand, when an end-effector without an uneven surface was used, release without adhesion was successful 6.25% of the time. Therefore, the superiority of a structure with an uneven

  3. Structural development of child's artistic expression

    OpenAIRE

    Sanja Filipović; Milica Vojvodić

    2017-01-01

    Abstract Structural development implies control and capability of the expression usage in terms of independent creative expression and making. Understanding of structural development of child's artistic expression as a phenomenon (which is suitable to child's age) has some implications on methodical acts considering artistic education of children and youngsters. Therefore, it is of unexceptional importance to know these laws as well as methodical acts which encourage the structural develop...

  4. 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.

  5. Outer space structure and development

    International Nuclear Information System (INIS)

    Zeldovich, J.; Novikov, I.

    1975-01-01

    A brief account is presented answering the question of what in fact the outer space we observe consists of. The principle of spatial homogeneity of the universe and the idea of non-stationary cosmology are discussed. The origin and the future development of the universe are explained using the two above mentioned and some other hypotheses. (J.K.)

  6. Outer space structure and development

    Energy Technology Data Exchange (ETDEWEB)

    Zeldovich, J; Novikov, I

    1975-10-01

    A brief account is presented answering the question of what in fact the outer space we observe consists of. The principle of spatial homogeneity of the universe and the idea of non-stationary cosmology are discussed. The origin and the future development of the universe are explained using the two above mentioned and some other hypotheses.

  7. Passive films at the nanoscale

    International Nuclear Information System (INIS)

    Maurice, Vincent; Marcus, Philippe

    2012-01-01

    Highlights: ► Nanoscale data on growth, structure and local properties of passive films reviewed. ► Preferential role of defects of passive films on the corrosion resistance emphasized. ► Effect of grain boundaries on local electronic properties shown by new data. ► Use of atomistic modeling to test mechanistic hypotheses illustrated. - Abstract: The nanometer scale chemical and structural aspects of ultrathin oxide passive films providing self-protection against corrosion to metals and alloys in aqueous environments are reviewed. Data on the nucleation and growth of 2D anodic oxide films, details on the atomic structure and nanostructure of 3D passive films, the preferential role of surface step edges in dissolution in the passive state and the preferential role of grain boundaries of the passive films in passivity breakdown are presented. Future perspectives are discussed, and exemplified by new data obtained on the relationship between the nanostructure of oxide passive films and their local electronic properties. Atomistic corrosion modeling by ab initio density functional theory (DFT) is illustrated by the example of interactions of chloride ions with hydroxylated oxide surfaces, including the role of surface step edges. Data obtained on well-defined substrate surfaces with surface analytical techniques are emphasized.

  8. Simultaneous topographical, electrical and optical microscopy of optoelectronic devices at the nanoscale

    KAUST Repository

    Kumar, Naresh

    2017-01-12

    Novel optoelectronic devices rely on complex nanomaterial systems where the nanoscale morphology and local chemical composition are critical to performance. However, the lack of analytical techniques that can directly probe these structure-property relationships at the nanoscale presents a major obstacle to device development. In this work, we present a novel method for non-destructive, simultaneous mapping of the morphology, chemical composition and photoelectrical properties with <20 nm spatial resolution by combining plasmonic optical signal enhancement with electrical-mode scanning probe microscopy. We demonstrate that this combined approach offers subsurface sensitivity that can be exploited to provide molecular information with a nanoscale resolution in all three spatial dimensions. By applying the technique to an organic solar cell device, we show that the inferred surface and subsurface composition distribution correlates strongly with the local photocurrent generation and explains macroscopic device performance. For instance, the direct measurement of fullerene phase purity can distinguish between high purity aggregates that lead to poor performance and lower purity aggregates (fullerene intercalated with polymer) that result in strong photocurrent generation and collection. We show that the reliable determination of the structure-property relationship at the nanoscale can remove ambiguity from macroscopic device data and support the identification of the best routes for device optimisation. The multi-parameter measurement approach demonstrated herein is expected to play a significant role in guiding the rational design of nanomaterial-based optoelectronic devices, by opening a new realm of possibilities for advanced investigation via the combination of nanoscale optical spectroscopy with a whole range of scanning probe microscopy modes.

  9. Solvent-free synthesis of nanosized hierarchical sodalite zeolite with a multi-hollow polycrystalline structure

    KAUST Repository

    Zeng, Shangjing; Wang, Runwei; Li, Ang; Huang, Weiwei; Zhang, Zongtao; Qiu, Shilun

    2016-01-01

    A solvent-free route is developed for preparing nanoscale sodalite zeolite with a multi-hollow structure. Furthermore, the synthesis of nanosized hollow sodalite polycrystalline aggregates with a mesoporous structure and high crystallinity

  10. Optimum Criteria for Developing Defined Structures

    Directory of Open Access Journals (Sweden)

    Ion IVAN

    2008-01-01

    Full Text Available Basic aspects concerning distributed applications are presented: definition, particularities and importance. For distributed applications linear, arborescent, graph structures are defined with different versions and aggregation methods. Distributed applications have associated structures which through their characteristics influence the costs of the stages in the development cycle and the exploitation costs transferred to each user. The complexity of the defined structures is analyzed. The minimum and maximum criteria are enumerated for optimizing distributed application structures.

  11. Manufacturing at Nanoscale: Top-Down, Bottom-up and System Engineering

    International Nuclear Information System (INIS)

    Zhang Xiang; Sun Cheng; Fang, Nicholas

    2004-01-01

    The current nano-technology revolution is facing several major challenges: to manufacture nanodevices below 20 nm, to fabricate three-dimensional complex nano-structures, and to heterogeneously integrate multiple functionalities. To tackle these grand challenges, the Center for Scalable and Integrated NAno-Manufacturing (SINAM), a NSF Nanoscale Science and Engineering Center, set its goal to establish a new manufacturing paradigm that integrates an array of new nano-manufacturing technologies, including the plasmonic imaging lithography and ultramolding imprint lithography aiming toward critical resolution of 1-10 nm and the hybrid top-down and bottom-up technologies to achieve massively parallel integration of heterogeneous nanoscale components into higher-order structures and devices. Furthermore, SINAM will develop system engineering strategies to scale-up the nano-manufacturing technologies. SINAMs integrated research and education platform will shed light to a broad range of potential applications in computing, telecommunication, photonics, biotechnology, health care, and national security

  12. 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.

  13. Structural reliability methods: Code development status

    Science.gov (United States)

    Millwater, Harry R.; Thacker, Ben H.; Wu, Y.-T.; Cruse, T. A.

    1991-05-01

    The Probabilistic Structures Analysis Method (PSAM) program integrates state of the art probabilistic algorithms with structural analysis methods in order to quantify the behavior of Space Shuttle Main Engine structures subject to uncertain loadings, boundary conditions, material parameters, and geometric conditions. An advanced, efficient probabilistic structural analysis software program, NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) was developed as a deliverable. NESSUS contains a number of integrated software components to perform probabilistic analysis of complex structures. A nonlinear finite element module NESSUS/FEM is used to model the structure and obtain structural sensitivities. Some of the capabilities of NESSUS/FEM are shown. A Fast Probability Integration module NESSUS/FPI estimates the probability given the structural sensitivities. A driver module, PFEM, couples the FEM and FPI. NESSUS, version 5.0, addresses component reliability, resistance, and risk.

  14. Isolation of nanoscale exosomes using viscoelastic effect

    Science.gov (United States)

    Hu, Guoqing; Liu, Chao

    2017-11-01

    Exosomes, molecular cargos secreted by almost all mammalian cells, are considered as promising biomarkers to identify many diseases including cancers. However, the small size of exosomes (30-200 nm) poses serious challenges on their isolation from the complex media containing a variety of extracellular vesicles (EVs) of different sizes, especially in small sample volumes. Here we develop a viscoelasticity-based microfluidic system to directly separate exosomes from cell culture media or serum in a continuous, size-dependent, and label-free manner. Using a small amount of biocompatible polymer as the additive into the media to control the viscoelastic forces exerted on EVs, we are able to achieve a high separation purity (>90%) and recovery (>80%) of exosomes. The size cutoff in viscoelasticity-based microfluidics can be easily controlled using different PEO concentrations. Based on this size-dependent viscoelastic separation strategy, we envision the handling of diverse nanoscale objects, such as gold nanoparticles, DNA origami structures, and quantum dots. This work was supported financially by National Natural Science Foundation of China (11572334, 91543125).

  15. Nanomaterial Case Studies: Nanoscale Titanium Dioxide ...

    Science.gov (United States)

    This draft document presents two case studies of nanoscale titanium dioxide (nano-TiO2) used (1) to remove arsenic from drinking water and (2) as an active ingredient in topical sunscreen. The draft case studies are organized around a comprehensive environmental assessment approach that combines a product life cycle framework with the risk assessment paradigm. The document does not draw conclusions about potential risks. Rather, the case studies are intended to help identify what needs to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. This draft document is part of a process that will inform the development of EPA’s research strategy to support nanomaterial risk assessments. The complex properties of various nanomaterials make evaluating them in the abstract or with generalizations difficult if not impossible. Thus, this document focuses on two specific uses of nano-TiO2, as a drinking water treatment and as topical sunscreen. These case studies do not represent completed or even preliminary assessments; rather, they present the structure for identifying and prioritizing research needed to support future assessments.

  16. Investigation of graphene-based nanoscale radiation sensitive materials

    Science.gov (United States)

    Robinson, Joshua A.; Wetherington, Maxwell; Hughes, Zachary; LaBella, Michael, III; Bresnehan, Michael

    2012-06-01

    Current state-of-the-art nanotechnology offers multiple benefits for radiation sensing applications. These include the ability to incorporate nano-sized radiation indicators into widely used materials such as paint, corrosion-resistant coatings, and ceramics to create nano-composite materials that can be widely used in everyday life. Additionally, nanotechnology may lead to the development of ultra-low power, flexible detection systems that can be embedded in clothing or other systems. Graphene, a single layer of graphite, exhibits exceptional electronic and structural properties, and is being investigated for high-frequency devices and sensors. Previous work indicates that graphene-oxide (GO) - a derivative of graphene - exhibits luminescent properties that can be tailored based on chemistry; however, exploration of graphene-oxide's ability to provide a sufficient change in luminescent properties when exposed to gamma or neutron radiation has not been carried out. We investigate the mechanisms of radiation-induced chemical modifications and radiation damage induced shifts in luminescence in graphene-oxide materials to provide a fundamental foundation for further development of radiation sensitive detection architectures. Additionally, we investigate the integration of hexagonal boron nitride (hBN) with graphene-based devices to evaluate radiation induced conductivity in nanoscale devices. Importantly, we demonstrate the sensitivity of graphene transport properties to the presence of alpha particles, and discuss the successful integration of hBN with large area graphene electrodes as a means to provide the foundation for large-area nanoscale radiation sensors.

  17. DNA-based construction at the nanoscale: emerging trends and applications

    Science.gov (United States)

    Lourdu Xavier, P.; Chandrasekaran, Arun Richard

    2018-02-01

    The field of structural DNA nanotechnology has evolved remarkably—from the creation of artificial immobile junctions to the recent DNA-protein hybrid nanoscale shapes—in a span of about 35 years. It is now possible to create complex DNA-based nanoscale shapes and large hierarchical assemblies with greater stability and predictability, thanks to the development of computational tools and advances in experimental techniques. Although it started with the original goal of DNA-assisted structure determination of difficult-to-crystallize molecules, DNA nanotechnology has found its applications in a myriad of fields. In this review, we cover some of the basic and emerging assembly principles: hybridization, base stacking/shape complementarity, and protein-mediated formation of nanoscale structures. We also review various applications of DNA nanostructures, with special emphasis on some of the biophysical applications that have been reported in recent years. In the outlook, we discuss further improvements in the assembly of such structures, and explore possible future applications involving super-resolved fluorescence, single-particle cryo-electron (cryo-EM) and x-ray free electron laser (XFEL) nanoscopic imaging techniques, and in creating new synergistic designer materials.

  18. Nano-scale Materials and Nano-technology Processes in Environmental Protection

    International Nuclear Information System (INIS)

    Vissokov, Gh; Tzvetkoff, T.

    2003-01-01

    A number of environmental and energy technologies have benefited substantially from nano-scale technology: reduced waste and improved energy efficiency; environmentally friendly composite structures; waste remediation; energy conversion. In this report examples of current achievements and paradigm shifts are presented: from discovery to application; a nano structured materials; nanoparticles in the environment (plasma chemical preparation); nano-porous polymers and their applications in water purification; photo catalytic fluid purification; hierarchical self-assembled nano-structures for adsorption of heavy metals, etc. Several themes should be considered priorities in developing nano-scale processes related to environmental management: 1. To develop understanding and control of relevant processes, including protein precipitation and crystallisation, desorption of pollutants, stability of colloidal dispersion, micelle aggregation, microbe mobility, formation and mobility of nanoparticles, and tissue-nanoparticle interaction. Emphasis should be given to processes at phase boundaries (solid-liquid, solid-gas, liquid-gas) that involve mineral and organic soil components, aerosols, biomolecules (cells, microbes), bio tissues, derived components such as bio films and membranes, and anthropogenic additions (e.g. trace and heavy metals); 2. To carry out interdisciplinary research that initiates Noel approaches and adopts new methods for characterising surfaces and modelling complex systems to problems at interfaces and other nano-structures in the natural environment, including those involving biological or living systems. New technological advances such as optical traps, laser tweezers, and synchrotrons are extending examination of molecular and nano-scale processes to the single-molecule or single-cell level; 3. To integrate understanding of the roles of molecular and nano-scale phenomena and behaviour at the meso- and/or macro-scale over a period of time

  19. Single molecules and single nanoparticles as windows to the nanoscale

    Science.gov (United States)

    Caldarola, Martín; Orrit, Michel

    2018-05-01

    Since the first optical detection of single molecules, they have been used as nanometersized optical sensors to explore the physical properties of materials and light-matter interaction at the nanoscale. Understanding nanoscale properties of materials is fundamental for the development of new technology that requires precise control of atoms and molecules when the quantum nature of matter cannot be ignored. In the following lines, we illustrate this journey into nanoscience with some experiments from our group.

  20. SU-G-TeP3-13: The Role of Nanoscale Energy Deposition in the Development of Gold Nanoparticle-Enhanced Radiotherapy

    International Nuclear Information System (INIS)

    Kirkby, C; Koger, B; Suchowerska, N; McKenzie, D

    2016-01-01

    Purpose: Gold nanoparticles (GNPs) can enhance radiotherapy effects. The high photoelectric cross section of gold relative to tissue, particularly at lower energies, leads to localized dose enhancement. However in a clinical context, photon energies must also be sufficient to reach a target volume at a given depth. These properties must be balanced to optimize such a therapy. Given that nanoscale energy deposition patterns around GNPs play a role in determining biological outcomes, in this work we seek to establish their role in this optimization process. Methods: The PENELOPE Monte Carlo code was used to generate spherical dose deposition kernels in 1000 nm diameter spheres around 50 nm diameter GNPs in response to monoenergetic photons incident on the GNP. Induced “lesions” were estimated by either a local effect model (LEM) or a mean dose model (MDM). The ratio of these estimates was examined for a range of photon energies (10 keV to 2 MeV), for three sets of linear-quadratic parameters. Results: The models produce distinct differences in expected lesion values, the lower the alpha-beta ratio, the greater the difference. The ratio of expected lesion values remained constant within 5% for energies of 40 keV and above across all parameter sets and rose to a difference of 35% for lower energies only for the lowest alpha-beta ratio. Conclusion: Consistent with other work, these calculations suggest nanoscale energy deposition patterns matter in predicting biological response to GNP-enhanced radiotherapy. However the ratio of expected lesions between the different models is largely independent of energy, indicating that GNP-enhanced radiotherapy scenarios can be optimized in photon energy without consideration of the nanoscale patterns. Special attention may be warranted for energies of 20 keV or below and low alpha-beta ratios.

  1. SU-G-TeP3-13: The Role of Nanoscale Energy Deposition in the Development of Gold Nanoparticle-Enhanced Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kirkby, C [Jack Ady Cancer Centre, Lethbridge, AB (Canada); The University of Calgary, Calgary, AB (Canada); Koger, B [The University of Calgary, Calgary, AB (Canada); Suchowerska, N [Chris O’Brien Lifehouse Camperdown, NSW (Australia); McKenzie, D [University of Sydney, Sydney, NSW (Australia)

    2016-06-15

    Purpose: Gold nanoparticles (GNPs) can enhance radiotherapy effects. The high photoelectric cross section of gold relative to tissue, particularly at lower energies, leads to localized dose enhancement. However in a clinical context, photon energies must also be sufficient to reach a target volume at a given depth. These properties must be balanced to optimize such a therapy. Given that nanoscale energy deposition patterns around GNPs play a role in determining biological outcomes, in this work we seek to establish their role in this optimization process. Methods: The PENELOPE Monte Carlo code was used to generate spherical dose deposition kernels in 1000 nm diameter spheres around 50 nm diameter GNPs in response to monoenergetic photons incident on the GNP. Induced “lesions” were estimated by either a local effect model (LEM) or a mean dose model (MDM). The ratio of these estimates was examined for a range of photon energies (10 keV to 2 MeV), for three sets of linear-quadratic parameters. Results: The models produce distinct differences in expected lesion values, the lower the alpha-beta ratio, the greater the difference. The ratio of expected lesion values remained constant within 5% for energies of 40 keV and above across all parameter sets and rose to a difference of 35% for lower energies only for the lowest alpha-beta ratio. Conclusion: Consistent with other work, these calculations suggest nanoscale energy deposition patterns matter in predicting biological response to GNP-enhanced radiotherapy. However the ratio of expected lesions between the different models is largely independent of energy, indicating that GNP-enhanced radiotherapy scenarios can be optimized in photon energy without consideration of the nanoscale patterns. Special attention may be warranted for energies of 20 keV or below and low alpha-beta ratios.

  2. Nanoscale inhomogeneity and photoacid generation dynamics in extreme ultraviolet resist materials

    Science.gov (United States)

    Wu, Ping-Jui; Wang, Yu-Fu; Chen, Wei-Chi; Wang, Chien-Wei; Cheng, Joy; Chang, Vencent; Chang, Ching-Yu; Lin, John; Cheng, Yuan-Chung

    2018-03-01

    The development of extreme ultraviolet (EUV) lithography towards the 22 nm node and beyond depends critically on the availability of resist materials that meet stringent control requirements in resolution, line edge roughness, and sensitivity. However, the molecular mechanisms that govern the structure-function relationships in current EUV resist systems are not well understood. In particular, the nanoscale structures of the polymer base and the distributions of photoacid generators (PAGs) should play a critical roles in the performance of a resist system, yet currently available models for photochemical reactions in EUV resist systems are exclusively based on homogeneous bulk models that ignore molecular-level details of solid resist films. In this work, we investigate how microscopic molecular organizations in EUV resist affect photoacid generations in a bottom-up approach that describes structure-dependent electron-transfer dynamics in a solid film model. To this end, molecular dynamics simulations and stimulated annealing are used to obtain structures of a large simulation box containing poly(4-hydroxystyrene) (PHS) base polymers and triphenylsulfonium based PAGs. Our calculations reveal that ion-pair interactions govern the microscopic distributions of the polymer base and PAG molecules, resulting in a highly inhomogeneous system with nonuniform nanoscale chemical domains. Furthermore, the theoretical structures were used in combination of quantum chemical calculations and the Marcus theory to evaluate electron transfer rates between molecular sites, and then kinetic Monte Carlo simulations were carried out to model electron transfer dynamics with molecular structure details taken into consideration. As a result, the portion of thermalized electrons that are absorbed by the PAGs and the nanoscale spatial distribution of generated acids can be estimated. Our data reveal that the nanoscale inhomogeneous distributions of base polymers and PAGs strongly affect the

  3. Interfibrillar stiffening of echinoderm mutable collagenous tissue demonstrated at the nanoscale.

    Science.gov (United States)

    Mo, Jingyi; Prévost, Sylvain F; Blowes, Liisa M; Egertová, Michaela; Terrill, Nicholas J; Wang, Wen; Elphick, Maurice R; Gupta, Himadri S

    2016-10-18

    The mutable collagenous tissue (MCT) of echinoderms (e.g., sea cucumbers and starfish) is a remarkable example of a biological material that has the unique attribute, among collagenous tissues, of being able to rapidly change its stiffness and extensibility under neural control. However, the mechanisms of MCT have not been characterized at the nanoscale. Using synchrotron small-angle X-ray diffraction to probe time-dependent changes in fibrillar structure during in situ tensile testing of sea cucumber dermis, we investigate the ultrastructural mechanics of MCT by measuring fibril strain at different chemically induced mechanical states. By measuring a variable interfibrillar stiffness (E IF ), the mechanism of mutability at the nanoscale can be demonstrated directly. A model of stiffness modulation via enhanced fibrillar recruitment is developed to explain the biophysical mechanisms of MCT. Understanding the mechanisms of MCT quantitatively may have applications in development of new types of mechanically tunable biomaterials.

  4. Development of the structural materials information center

    International Nuclear Information System (INIS)

    Oland, C.B.; Naus, D.J.

    1990-01-01

    The U.S. Nuclear Regulatory Commission has initiated a Structural Aging Program at the Oak Ridge National Laboratory to identify potential structural safety issues related to continued service of nuclear power plants and to establish criteria for evaluating and resolving these issues. One of the tasks in this program focuses on the establishment of a Structural Materials Information Center where data and information on the time variation of concrete and other structural material properties under the influence of pertinent environmental stressors and aging factors are being collected and assembled into a database. This database will be used to assist in the prediction of potential long-term deterioration of critical structural components in nuclear power plants and to establish limits on hostile environmental exposure for these structures and materials. Two complementary database formats have been developed. The Structural Materials Handbook is an expandable, hard copy handbook that contains complete sets of data and information for selected portland cement concrete, metallic reinforcement, prestressing tendon, and structural steel materials. The Structural Materials Electronic Database is accessible by an IBM-compatible personal computer and provides an efficient means for searching the various database files to locate materials with similar properties. The database formats have been developed to accommodate data and information on the time-variation of concrete and other structural material properties. To date, the database includes information on concrete, reinforcement, prestressing, and structural steel materials

  5. 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.

  6. Dopant atoms as quantum components in silicon nanoscale devices

    Science.gov (United States)

    Zhao, Xiaosong; Han, Weihua; Wang, Hao; Ma, Liuhong; Li, Xiaoming; Zhang, Wang; Yan, Wei; Yang, Fuhua

    2018-06-01

    Recent progress in nanoscale fabrication allows many fundamental studies of the few dopant atoms in various semiconductor nanostructures. Since the size of nanoscale devices has touched the limit of the nature, a single dopant atom may dominate the performance of the device. Besides, the quantum computing considered as a future choice beyond Moore's law also utilizes dopant atoms as functional units. Therefore, the dopant atoms will play a significant role in the future novel nanoscale devices. This review focuses on the study of few dopant atoms as quantum components in silicon nanoscale device. The control of the number of dopant atoms and unique quantum transport characteristics induced by dopant atoms are presented. It can be predicted that the development of nanoelectronics based on dopant atoms will pave the way for new possibilities in quantum electronics. Project supported by National Key R&D Program of China (No. 2016YFA0200503).

  7. 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

  8. Friction laws at the nanoscale.

    Science.gov (United States)

    Mo, Yifei; Turner, Kevin T; Szlufarska, Izabela

    2009-02-26

    Macroscopic laws of friction do not generally apply to nanoscale contacts. Although continuum mechanics models have been predicted to break down at the nanoscale, they continue to be applied for lack of a better theory. An understanding of how friction force depends on applied load and contact area at these scales is essential for the design of miniaturized devices with optimal mechanical performance. Here we use large-scale molecular dynamics simulations with realistic force fields to establish friction laws in dry nanoscale contacts. We show that friction force depends linearly on the number of atoms that chemically interact across the contact. By defining the contact area as being proportional to this number of interacting atoms, we show that the macroscopically observed linear relationship between friction force and contact area can be extended to the nanoscale. Our model predicts that as the adhesion between the contacting surfaces is reduced, a transition takes place from nonlinear to linear dependence of friction force on load. This transition is consistent with the results of several nanoscale friction experiments. We demonstrate that the breakdown of continuum mechanics can be understood as a result of the rough (multi-asperity) nature of the contact, and show that roughness theories of friction can be applied at the nanoscale.

  9. Distance Learning Plan Development: Initiating Organizational Structures

    National Research Council Canada - National Science Library

    Poole, Clifton

    1998-01-01

    .... Army distance learning plan managers to examine the DLPs they were directing. The analysis showed that neither army nor civilian distance learning plan managers used formalized requirements for organizational structure development (OSD...

  10. Magnetization switching schemes for nanoscale three-terminal spintronics devices

    Science.gov (United States)

    Fukami, Shunsuke; Ohno, Hideo

    2017-08-01

    Utilizing spintronics-based nonvolatile memories in integrated circuits offers a promising approach to realize ultralow-power and high-performance electronics. While two-terminal devices with spin-transfer torque switching have been extensively developed nowadays, there has been a growing interest in devices with a three-terminal structure. Of primary importance for applications is the efficient manipulation of magnetization, corresponding to information writing, in nanoscale devices. Here we review the studies of current-induced domain wall motion and spin-orbit torque-induced switching, which can be applied to the write operation of nanoscale three-terminal spintronics devices. For domain wall motion, the size dependence of device properties down to less than 20 nm will be shown and the underlying mechanism behind the results will be discussed. For spin-orbit torque-induced switching, factors governing the threshold current density and strategies to reduce it will be discussed. A proof-of-concept demonstration of artificial intelligence using an analog spin-orbit torque device will also be reviewed.

  11. Nanoscale piezoelectric vibration energy harvester design

    Science.gov (United States)

    Foruzande, Hamid Reza; Hajnayeb, Ali; Yaghootian, Amin

    2017-09-01

    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.

  12. Activity and Stability of Nanoscale Oxygen Reduction Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Shao-Horn, Yang

    2015-07-28

    Design of highly active and stable nanoscale catalysts for electro-oxidation of small organic molecules is of great importance to the development of efficient fuel cells. The amount and instability of Pt-based catalysts in the cathode limits the cost, efficiency and lifetime of proton exchange membrane fuel cells. We developed a microscopic understanding of the factors governing activity and stability in Pt and PtM alloys. Experimental efforts were focused on probing the size and shape dependence of ORR activity of Pt-based nanoparticles supported on carbon nanotubes. A microscopic understanding of the activity was achieved by correlating voltammetry and rotating ring disk electrodes to surface atomic and electronic structures, which were elucidated predominantly by high-resolution transmission electron microscopy (HRTEM), Scanning transmission electron microscopy energy dispersive X-ray Spectroscopy (STEM-EDS) and synchrotron X-ray absorption spectroscopy (XAS).

  13. Nanoscale thermal transport. II. 2003-2012

    Science.gov (United States)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-01

    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 thermal

  14. Nanoscale thermal transport. II. 2003–2012

    International Nuclear Information System (INIS)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-01-01

    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

  15. Nanoscale-Agglomerate-Mediated Heterogeneous Nucleation.

    Science.gov (United States)

    Cha, Hyeongyun; Wu, Alex; Kim, Moon-Kyung; Saigusa, Kosuke; Liu, Aihua; Miljkovic, Nenad

    2017-12-13

    Water vapor condensation on hydrophobic surfaces has received much attention due to its ability to rapidly shed water droplets and enhance heat transfer, anti-icing, water harvesting, energy harvesting, and self-cleaning performance. However, the mechanism of heterogeneous nucleation on hydrophobic surfaces remains poorly understood and is attributed to defects in the hydrophobic coating exposing the high surface energy substrate. Here, we observe the formation of high surface energy nanoscale agglomerates on hydrophobic coatings after condensation/evaporation cycles in ambient conditions. To investigate the deposition dynamics, we studied the nanoscale agglomerates as a function of condensation/evaporation cycles via optical and field emission scanning electron microscopy (FESEM), microgoniometric contact angle measurements, nucleation statistics, and energy dispersive X-ray spectroscopy (EDS). The FESEM and EDS results indicated that the nanoscale agglomerates stem from absorption of sulfuric acid based aerosol particles inside the droplet and adsorption of volatile organic compounds such as methanethiol (CH 3 SH), dimethyl disulfide (CH 3 SSCH), and dimethyl trisulfide (CH 3 SSSCH 3 ) on the liquid-vapor interface during water vapor condensation, which act as preferential sites for heterogeneous nucleation after evaporation. The insights gained from this study elucidate fundamental aspects governing the behavior of both short- and long-term heterogeneous nucleation on hydrophobic surfaces, suggest previously unexplored microfabrication and air purification techniques, and present insights into the challenges facing the development of durable dropwise condensing surfaces.

  16. Nanoscale dose deposition in cell structures under X-ray irradiation treatment assisted with nanoparticles of a set of elements: an analytical approach to cell survival

    Energy Technology Data Exchange (ETDEWEB)

    Melo B, W.; Barboza F, M. [Universidad de Sonora, Departamento de Investigacion en Fisica, 83000 Hermosillo, Sonora (Mexico); Chernov, G., E-mail: g.chernovch@gmail.com [Universidad de Sonora, Departamento de Fisica, 83000 Hermosillo, Sonora (Mexico)

    2016-10-15

    The goal of combining nanoparticles (Nps) with radiation therapy is to increase the differential effect between healthy and tumor tissues. Only some elements have been investigated to be used as radiosensitizers and no systematic experimental or theoretical comparisons between different materials have been developed. MacMahon, et al. (Nano scale, 2016, 8, 581) presents the first systematic computational study of the impact of elemental composition on nanoparticle radiation interaction for kilo voltage and megavoltage X-ray exposure, for a range of elements (Z = 14 - 80). In this study we present and analytical model to assess the cell survival modification responses of cell cultures under irradiation treatments with keV X-rays assisted with Nps of different materials as platinum, hafnium, gadolinium, gold, germanium, iodine and iron. This model starts from the data of radial dose deposition around a single 20 nm diameter Np irradiated with photons of an energy 20 keV higher than the element K-shell binding energy to the nano scale probability of dose distribution inside cell structures with embedded Nps (the assessment of the average dose and the average squared dose in cell structure). Also based on the Local Effect Model we estimate potential biological effects, as is the case of the Relative Biological Effectiveness (RBE). Nano scale dose deposition exhibits a complex dependence on atomic number, as a consequence of the variations in secondary Auger electron spectra, this is manifested in significant variations in RBE. Upon in vitro experiments RBE varies from 1 to 1.6. Values representative of a high radiosensitization were observed for lower energies, ones that are well reproduced by our analytical analysis for cell cultures with a homogeneous distribution of different material Nps. (Author)

  17. Nanoscale dose deposition in cell structures under X-ray irradiation treatment assisted with nanoparticles of a set of elements: an analytical approach to cell survival

    International Nuclear Information System (INIS)

    Melo B, W.; Barboza F, M.; Chernov, G.

    2016-10-01

    The goal of combining nanoparticles (Nps) with radiation therapy is to increase the differential effect between healthy and tumor tissues. Only some elements have been investigated to be used as radiosensitizers and no systematic experimental or theoretical comparisons between different materials have been developed. MacMahon, et al. (Nano scale, 2016, 8, 581) presents the first systematic computational study of the impact of elemental composition on nanoparticle radiation interaction for kilo voltage and megavoltage X-ray exposure, for a range of elements (Z = 14 - 80). In this study we present and analytical model to assess the cell survival modification responses of cell cultures under irradiation treatments with keV X-rays assisted with Nps of different materials as platinum, hafnium, gadolinium, gold, germanium, iodine and iron. This model starts from the data of radial dose deposition around a single 20 nm diameter Np irradiated with photons of an energy 20 keV higher than the element K-shell binding energy to the nano scale probability of dose distribution inside cell structures with embedded Nps (the assessment of the average dose and the average squared dose in cell structure). Also based on the Local Effect Model we estimate potential biological effects, as is the case of the Relative Biological Effectiveness (RBE). Nano scale dose deposition exhibits a complex dependence on atomic number, as a consequence of the variations in secondary Auger electron spectra, this is manifested in significant variations in RBE. Upon in vitro experiments RBE varies from 1 to 1.6. Values representative of a high radiosensitization were observed for lower energies, ones that are well reproduced by our analytical analysis for cell cultures with a homogeneous distribution of different material Nps. (Author)

  18. Simple Methods for Production of Nanoscale Metal Oxide Films from Household Sources

    Science.gov (United States)

    Campbell, Dean J.; Baliss, Michelle S.; Hinman, Jordan J.; Ziegenhorn, John W.; Andrews, Mark J.; Stevenson, Keith J.

    2013-01-01

    Production of thin metal oxide films was recently explored as part of an outreach program with a goal of producing nanoscale structures with household items. Household items coated with various metals or titanium compounds can be heated to produce colorful films with nanoscale thicknesses. As part of a materials chemistry laboratory experiment…

  19. Development of the field of structural physiology

    Science.gov (United States)

    FUJIYOSHI, Yoshinori

    2015-01-01

    Electron crystallography is especially useful for studying the structure and function of membrane proteins — key molecules with important functions in neural and other cells. Electron crystallography is now an established technique for analyzing the structures of membrane proteins in lipid bilayers that closely simulate their natural biological environment. Utilizing cryo-electron microscopes with helium-cooled specimen stages that were developed through a personal motivation to understand the functions of neural systems from a structural point of view, the structures of membrane proteins can be analyzed at a higher than 3 Å resolution. This review covers four objectives. First, I introduce the new research field of structural physiology. Second, I recount some of the struggles involved in developing cryo-electron microscopes. Third, I review the structural and functional analyses of membrane proteins mainly by electron crystallography using cryo-electron microscopes. Finally, I discuss multifunctional channels named “adhennels” based on structures analyzed using electron and X-ray crystallography. PMID:26560835

  20. Structural development of child's artistic expression

    Directory of Open Access Journals (Sweden)

    Sanja Filipović

    2017-03-01

    Full Text Available Structural development implies control and capability of the expression usage in terms of independent creative expression and making. Understanding of structural development of child's artistic expression as a phenomenon (which is suitable to child's age has some implications on methodical acts considering the artistic education of children and youngsters. Therefore, it is of unexceptional importance to know these laws as well as methodical acts which encourage the structural development of artistic capabilities from an early age. Various experts dealt with this phenomenon, particularly Bogomil Karlavaris. In his methodical research, he has given an unexceptional part to this problem. It has been a starting point for analysis of certain methodical questions which are included in this work.

  1. History of Planning Structure Development in Irkutsk

    Science.gov (United States)

    Kulakov, A. I.; Ree, A. U.

    2017-11-01

    The development of Irkutsk was spontaneous; the first streets represented a rather complex system of streets, dead ends, lanes. Throughout the history of the city, several general plans and development projects have been implemented (but not completely). Unlike other large Siberian cities (Novosibirsk, Krasnoyarsk), Irkutsk managed to preserve its historical appearance, architecture and initial planning. During its history the city has passed five stages of the planning structure development. The first stage of the city’s history coincides with the formation of the Russian settlements network in Eastern Siberia from the middle of the 17th to the end of the 18th centuries. Like many other Siberian cities, Irkutsk began its evolution from a fortified stockaded town. By the end of the 17th century a trading quarter appeared outside its walls. Currently, the city is developing and growing, so, a relevant issue of the further development direction of the Irkutsk planning structure naturally arises.

  2. Development of Technology for Structural Integrity Evaluation

    International Nuclear Information System (INIS)

    Choun, Young Sun; Choi, I. K.; Kim, M. K. and others

    2005-03-01

    The purpose of this study is a development of seismic safety and structural integrity evaluation method of the structure in the Nuclear Power plant (NPP). The purpose of 1st sub-Topic is the development and improvement of the seismic safety evaluation methodology for the Nuclear Power Plant structures and safety related equipment. The purpose of 2nd sub-topic is the increasing of structure and equipment seismic capacity through the reducing of seismic force. The purpose of 3rd sub-topic is the development of 3-D nonlinear finite element analysis program for prestressed concrete containment building. The last purpose if the evaluation of the failure mechanism of containment structure and structure capacity and the assessment of integrity of containment through the of leakage test. As a result of this research, there are many research results were produced. The scenario earthquake developing method was developed and the effect of the structures and equipment was analyzed. The effectiveness of isolation system was determined and optimum isolation systems for each equipment were selected. The NUCAS-3D program for the 3 dimensional numerical analysis of containment building using the embedded tendon element and rebar element was developed. The tension behavior of containment building was examined and the leakage rate of the concrete crack was determined. The results of this research can be successfully used for many fields of integrity of NPP site. It can be used for development of design earthquake for the seismic design and safety evaluation and establishment of seismic safety evaluation program and seismic capacity improvement program for existing NPP. In case of seismic isolation part, it can be used for the application to the selection of optimum isolation devices for equipment isolation and to the effective evaluation of each seismic isolation devices. In containment analysis part, it can be used for ultimate pressure capacity evaluation of prestressed concrete

  3. Nanoscale temperature sensing using single defects in diamond

    International Nuclear Information System (INIS)

    Philipp Neumann

    2014-01-01

    We experimentally demonstrate a novel nanoscale temperature sensing technique that is based on single atomic defects in diamonds, namely nitrogen vacancy color centers. Sample sizes range from millimeter down to a few tens of nanometers. In particular nanodiamonds were used as dispersed probes to acquire spatially resolved temperature profiles utilizing the sensitivity of the optically accessible electron spin level structure we achieve a temperature noise floor of 5mK/Mhz for bulk diamond and 130mK/Mhz for nanodiamonds and accuracies of 1mK. To this end we have developed a new decoupling technique in order to suppress to otherwise limiting effect of magnetic field fluctuations. In addition, high purity isotopically enriched 12C artificial diamonds is used. The high sensitivity to temperature changes adds to the well studied sensitivities to magnetic and electric fields and makes NV diamond a multipurpose nanoprobe. (author)

  4. The mechanical behavior of nanoscale metallic multilayers: A survey

    Science.gov (United States)

    Zhou, Q.; Xie, J. Y.; Wang, F.; Huang, P.; Xu, K. W.; Lu, T. J.

    2015-06-01

    The mechanical behavior of nanoscale metallic multilayers (NMMs) has attracted much attention from both scientific and practical views. Compared with their monolithic counterparts, the large number of interfaces existing in the NMMs dictates the unique behavior of this special class of structural composite materials. While there have been a number of reviews on the mechanical mechanism of microlaminates, the rapid development of nanotechnology brought a pressing need for an overview focusing exclusively on a property-based definition of the NMMs, especially their size-dependent microstructure and mechanical performance. This article attempts to provide a comprehensive and up-to-date review on the microstructure, mechanical property and plastic deformation physics of NMMs. We hope this review could accomplish two purposes: (1) introducing the basic concepts of scaling and dimensional analysis to scientists and engineers working on NMM systems, and (2) providing a better understanding of interface behavior and the exceptional qualities the interfaces in NMMs display at atomic scale.

  5. Nanoscale defect architectures and their influence on material properties

    Science.gov (United States)

    Campbell, Branton

    2006-10-01

    Diffraction studies of long-range order often permit one to unambiguously determine the atomic structure of a crystalline material. Many interesting material properties, however, are dominated by nanoscale crystal defects that can't be characterized in this way. Fortunately, advances in x-ray detector technology, synchrotron x-ray source brightness, and computational power make it possible to apply new methods to old problems. Our research group uses multi-megapixel x-ray cameras to map out large contiguous volumes of reciprocal space, which can then be visually explored using graphics engines originally developed by the video-game industry. Here, I will highlight a few recent examples that include high-temperature superconductors, colossal magnetoresistors and piezoelectric materials.

  6. Development of Ultra-High Mechanical Damping Structures Based on the Nano-Scale Properties of Shape Memory Alloys

    Science.gov (United States)

    2013-07-29

    Condensada Facultad de Ciencia y Tecnologia Aptdo 644 Bilbao, Spain 48080 EOARD Grant 10-3074 Report Date: July 2013 Final Report...Ciencia y Tecnologia Aptdo 644 Bilbao, Spain 48080 8. PERFORMING ORGANIZATION REPORT NUMBER N/A 9. SPONSORING/MONITORING AGENCY...Ciencia y Tecnologia , Aptdo 644, 48080 Bilbao, Spain. E-mail: jose.sanjuan@ehu.es Summary In recent years it was discovered that micro and nano

  7. Development of Ultra-high Mechanical Damping Structures Based on Nano-scale Properties of Shape Memory Alloys

    Science.gov (United States)

    2011-07-27

    Alloys Jose San Juan Universidad del Pais Vasco Department of Physics of Condensed Matter Facultd de Ciencia y Tecnologia Bilbao...Facultd de Ciencia y Tecnologia Bilbao, Spain 48080 8. PERFORMING ORGANIZATION REPORT NUMBER N/A 9. SPONSORING/MONITORING AGENCY NAME(S

  8. Nanoscale phase change memory materials.

    Science.gov (United States)

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

    2012-08-07

    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.

  9. Visualizing copper assisted graphene growth in nanoscale

    Science.gov (United States)

    Rosmi, Mohamad Saufi; Yusop, Mohd Zamri; Kalita, Golap; Yaakob, Yazid; Takahashi, Chisato; Tanemura, Masaki

    2014-01-01

    Control synthesis of high quality large-area graphene on transition metals (TMs) by chemical vapor deposition (CVD) is the most fascinating approach for practical device applications. Interaction of carbon atoms and TMs is quite critical to obtain graphene with precise layer number, crystal size and structure. Here, we reveal a solid phase reaction process to achieve Cu assisted graphene growth in nanoscale by in-situ transmission electron microscope (TEM). Significant structural transformation of amorphous carbon nanofiber (CNF) coated with Cu is observed with an applied potential in a two probe system. The coated Cu particle recrystallize and agglomerate toward the cathode with applied potential due to joule heating and large thermal gradient. Consequently, the amorphous carbon start crystallizing and forming sp2 hybridized carbon to form graphene sheet from the tip of Cu surface. We observed structural deformation and breaking of the graphene nanoribbon with a higher applied potential, attributing to saturated current flow and induced Joule heating. The observed graphene formation in nanoscale by the in-situ TEM process can be significant to understand carbon atoms and Cu interaction. PMID:25523645

  10. Ecosocial System: Structure, Development Laws and Functioning

    Directory of Open Access Journals (Sweden)

    E. I. Alekseev

    2004-01-01

    Full Text Available The paper substantiates necessity to develop a unified system of socio-ecological knowledge. Ecosophy being a forming component of dialectic-materialistic philosophy has been proposed as such system. Structure, development laws and functioning of eco-social system are considered as a part of ecosophy theory. Standard laws and ecological principles being widely recognized by ecologically orientated theorists are stated in the paper.

  11. 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...

  12. Photogrammetry Methodology Development for Gossamer Spacecraft Structures

    Science.gov (United States)

    Pappa, Richard S.; Jones, Thomas W.; Black, Jonathan T.; Walford, Alan; Robson, Stuart; Shortis, Mark R.

    2002-01-01

    Photogrammetry--the science of calculating 3D object coordinates from images--is a flexible and robust approach for measuring the static and dynamic characteristics of future ultra-lightweight and inflatable space structures (a.k.a., Gossamer structures), such as large membrane reflectors, solar sails, and thin-film solar arrays. Shape and dynamic measurements are required to validate new structural modeling techniques and corresponding analytical models for these unconventional systems. This paper summarizes experiences at NASA Langley Research Center over the past three years to develop or adapt photogrammetry methods for the specific problem of measuring Gossamer space structures. Turnkey industrial photogrammetry systems were not considered a cost-effective choice for this basic research effort because of their high purchase and maintenance costs. Instead, this research uses mainly off-the-shelf digital-camera and software technologies that are affordable to most organizations and provide acceptable accuracy.

  13. Mechanical Model Development for Composite Structural Supercapacitors

    Science.gov (United States)

    Ricks, Trenton M.; Lacy, Thomas E., Jr.; Santiago, Diana; Bednarcyk, Brett A.

    2016-01-01

    Novel composite structural supercapacitor concepts have recently been developed as a means both to store electrical charge and to provide modest mechanical load carrying capability. Double-layer composite supercapacitors are often fabricated by impregnating a woven carbon fiber fabric, which serves as the electrodes, with a structural polymer electrolyte. Polypropylene or a glass fabric is often used as the separator material. Recent research has been primarily limited to evaluating these composites experimentally. In this study, mechanical models based on the Multiscale Generalized Method of Cells (MSGMC) were developed and used to calculate the shear and tensile properties and response of two composite structural supercapacitors from the literature. The modeling approach was first validated against traditional composite laminate data. MSGMC models for composite supercapacitors were developed, and accurate elastic shear/tensile properties were obtained. It is envisioned that further development of the models presented in this work will facilitate the design of composite components for aerospace and automotive applications and can be used to screen candidate constituent materials for inclusion in future composite structural supercapacitor concepts.

  14. Nucleon structure in view of recent developments

    International Nuclear Information System (INIS)

    Martin, A.D.

    1993-01-01

    We review the present knowledge of the parton structure of the proton. We discuss recent developments concerning deep-inelastic scattering and parton distributions at small x, with emphasis on the predictions of perturbative QCD that are relevant to the experiment at HERA. (author). 37 refs, 16 figs, 1 tab

  15. Development and optimization of containment structure concepts

    International Nuclear Information System (INIS)

    Reuter, H.R.; Whitcraft, J.S. Jr.

    1976-01-01

    The development of prestressed concrete containment structures for nuclear power plants designed, constructed, and tested by Bechtel Power Corporation has been divided into three general stages or generations. The distinctions that characterize these generations are: the shape of the dome, the number of buttresses, the size and arrangement of the post-tensioning tendons, and the design level of the prestressing forces. (author)

  16. Development of the Structural Materials Information Center

    International Nuclear Information System (INIS)

    Oland, C.B.; Naus, D.J.

    1990-01-01

    The US Nuclear Regulatory Commission has initiated a Structural Aging Program at the Oak Ridge National Laboratory to identify potential structural safety issues related to continued service of nuclear power plants and to establish criteria for evaluating and resolving these issues. One of the tasks in this program focuses on the establishment of a Structural Materials Information Center where data and information on the time variation of concrete and other structural material properties under the influence of pertinent environmental stressors and aging factors are being collected and assembled into a data base. This data base will be used to assist in the prediction of potential long-term deterioration of critical structural components in nuclear power plants and to establish limits on hostile environmental exposure for these structures and materials. Two complementary data base formats have been developed. The Structural Materials Handbook is an expandable, hard-copy reference document that contains complete sets of data and information for selected portland cement concrete, metallic reinforcement, prestressing tendon, and structural steel materials. Baseline data, reference properties and environmental information are presented in the handbook as tables, notes and graphs. The handbook, which will be published in four volumes, serves as the information source for the electronic data base. The Structural Materials Electronic Data Base is accessible by an IBM-compatible personal computer and provides an efficient means for searching the various data base files to locate materials with similar properties. Properties will be reported in the International System of Units (SI) and in customary units whenever possible. 7 refs., 3 figs., 4 tabs

  17. Development of porous structure simulator for multi-scale simulation of irregular porous catalysts

    International Nuclear Information System (INIS)

    Koyama, Michihisa; Suzuki, Ai; Sahnoun, Riadh; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Kubo, Momoji; Del Carpio, Carlos A.; Miyamoto, Akira

    2008-01-01

    Efficient development of highly functional porous materials, used as catalysts in the automobile industry, demands a meticulous knowledge of the nano-scale interface at the electronic and atomistic scale. However, it is often difficult to correlate the microscopic interfacial interactions with macroscopic characteristics of the materials; for instance, the interaction between a precious metal and its support oxide with long-term sintering properties of the catalyst. Multi-scale computational chemistry approaches can contribute to bridge the gap between micro- and macroscopic characteristics of these materials; however this type of multi-scale simulations has been difficult to apply especially to porous materials. To overcome this problem, we have developed a novel mesoscopic approach based on a porous structure simulator. This simulator can construct automatically irregular porous structures on a computer, enabling simulations with complex meso-scale structures. Moreover, in this work we have developed a new method to simulate long-term sintering properties of metal particles on porous catalysts. Finally, we have applied the method to the simulation of sintering properties of Pt on alumina support. This newly developed method has enabled us to propose a multi-scale simulation approach for porous catalysts

  18. Development of thermoplastic composite aircraft structures

    Science.gov (United States)

    Renieri, Michael P.; Burpo, Steven J.; Roundy, Lance M.; Todd, Stephanie A.; Kim, H. J.

    1992-01-01

    Efforts focused on the use of thermoplastic composite materials in the development of structural details associated with an advanced fighter fuselage section with applicability to transport design. In support of these designs, mechanics developments were conducted in two areas. First, a dissipative strain energy approach to material characterization and failure prediction, developed at the Naval Research Laboratory, was evaluated as a design/analysis tool. Second, a finite element formulation for thick composites was developed and incorporated into a lug analysis method which incorporates pin bending effects. Manufacturing concepts were developed for an upper fuel cell cover. A detailed trade study produced two promising concepts: fiber placement and single-step diaphragm forming. Based on the innovative design/manufacturing concepts for the fuselage section primary structure, elements were designed, fabricated, and structurally tested. These elements focused on key issues such as thick composite lugs and low cost forming of fastenerless, stiffener/moldine concepts. Manufacturing techniques included autoclave consolidation, single diaphragm consolidation (SDCC) and roll-forming.

  19. PREFACE: Nanoscale science and technology

    Science.gov (United States)

    Bellucci, Stefano

    2008-11-01

    , nanopowders) were discussed. Ab initio simulations on the atomic and electronic structure of single-walled BN nanotubes and nanoarches were illustrated by Yu F Zhukovskii. M B Muradov talked about nanoparticles of cadmium selenide and cadmium sulfide, which yield one of the perspective materials for application to solar cell elements, high-speed computing systems, catalyses and biomarkers in medicine. In the presentation, the process of transformation of nanoparticles cadmium of sulfide to nanoparticles of cadmium selenide by an ionic exchange from solutions of electrolytes was considered. The size of particles was controlled by the quantity of growth cycles. After manufacturing, the structures were investigated by atomic force microscope (AFM). Structures CdS:polymer transformed into CdSe:polymer with the help of ion-exchange. For the realization of the process of ionic exchange, solutions were prepared containing bivalent ions of selenium as follows: NaBH4 and Se in a weight parity 2:1 added in water 4NaBH4+2Se+7H2O→2NaHSe+Na2B4O7+14H2 In the prepared solution nanostructures CdS:polymer were immersed. Time of endurance was 2 h. After an ionic exchange the obtained structures were investigated by means of EDAX on a chemical composition. Results of analyses have shown that atoms of sulfur are completely replaced by selenium. The band gap of nanoparticles in comparison with initial samples is displaced in the long-wave area. It is connected with the fact that the width of the band gap of bulk crystals CdSe (1.74 eV) is smaller than the band gap of CdS (2.42 eV). Optical microscopy with spatial resolution beyond the diffraction limit obtained by using near field techniques was the subject of S Prato's talk. Scanning near field optical microscopy (SNOM) has developed into a powerful tool to investigate local optical properties that depend on heterogeneity of materials at nanoscale and to study nanoenvironment of biosystems. Crucial topics in SNOM are: force sensitivity and

  20. European structural materials development for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Schaaf, B. van der E-mail: vanderschaaf@nrg-nl.com; Ehrlich, K.; Fenici, P.; Tavassoli, A.A.; Victoria, M

    2000-09-01

    Leading long term considerations for choices in the European Long Term Technology programme are the high temperature mechanical- and compatibility properties of structural materials under neutron irradiation. The degrees of fabrication process freedom are closely investigated to allow the construction of complex shapes. Another important consideration is the activation behaviour of the structural material. The ideal solution is the recycling of the structural materials after a relatively short 'cooling' period. The structural materials development in Europe has three streams. The first serves the design and construction of ITER and is closely connected to the choice made: water cooled austenitic stainless steel. The second development stream is to support the design and construction of DEMO relevant blanket modules to be tested in ITER. The helium cooled pebble bed and the water cooled liquid lithium concept rely both on RAFM steel. The goal of the third stream is to investigate the potential of advanced materials for fusion power reactors beyond DEMO. The major contending materials: SiCSiC composites, vanadium, titanium and chromium alloys hold the promise of high operating temperatures, but RAFM has also a high temperature potential applying oxide dispersion strengthening. The development of materials for fusion power application requires a high flux 14 MeV neutron source to simulate the fusion power environment.

  1. Lessons learned from nanoscale specimens tested by MEMS-based apparatus

    Science.gov (United States)

    Elhebeary, Mohamed; Saif, M. Taher A.

    2017-06-01

    The last two decades were marked by the innovative synthesis of nanomaterials and devices. The success of these devices hinges on the mechanical properties of nanomaterials and an understanding of their deformation and failure mechanisms. Many novel testing techniques have been developed to test materials at small scale. This paper reviews the state-of-the-art microelectromechanical systems (MEMS) apparatus developed to characterize materials at nanoscale, and the key insights gained on structure-property relations of materials through these characterizations. Finally, new applications of MEMS in testing living materials, such as tissues and cells, for disease diagnosis and prognosis are discussed.

  2. Lessons learned from nanoscale specimens tested by MEMS-based apparatus

    International Nuclear Information System (INIS)

    Elhebeary, Mohamed; Saif, M Taher A

    2017-01-01

    The last two decades were marked by the innovative synthesis of nanomaterials and devices. The success of these devices hinges on the mechanical properties of nanomaterials and an understanding of their deformation and failure mechanisms. Many novel testing techniques have been developed to test materials at small scale. This paper reviews the state-of-the-art microelectromechanical systems (MEMS) apparatus developed to characterize materials at nanoscale, and the key insights gained on structure-property relations of materials through these characterizations. Finally, new applications of MEMS in testing living materials, such as tissues and cells, for disease diagnosis and prognosis are discussed. (topical review)

  3. Nursing Competency: Definition, Structure and Development

    Science.gov (United States)

    Fukada, Mika

    2018-01-01

    Nursing competency includes core abilities that are required for fulfilling one’s role as a nurse. Therefore, it is important to clearly define nursing competency to establish a foundation for nursing education curriculum. However, while the concepts surrounding nursing competency are important for improving nursing quality, they are still not yet completely developed. Thus, challenges remain in establishing definitions and structures for nursing competency, competency levels necessary for nursing professionals, training methods and so on. In the present study, we reviewed the research on definitions and attributes of nursing competency in Japan as well as competency structure, its elements and evaluation. Furthermore, we investigated training methods to teach nursing competency. PMID:29599616

  4. Nursing Competency: Definition, Structure and Development.

    Science.gov (United States)

    Fukada, Mika

    2018-03-01

    Nursing competency includes core abilities that are required for fulfilling one's role as a nurse. Therefore, it is important to clearly define nursing competency to establish a foundation for nursing education curriculum. However, while the concepts surrounding nursing competency are important for improving nursing quality, they are still not yet completely developed. Thus, challenges remain in establishing definitions and structures for nursing competency, competency levels necessary for nursing professionals, training methods and so on. In the present study, we reviewed the research on definitions and attributes of nursing competency in Japan as well as competency structure, its elements and evaluation. Furthermore, we investigated training methods to teach nursing competency.

  5. Nanoscale organic ferroelectric resistive switches

    NARCIS (Netherlands)

    Khikhlovskyi, V.; Wang, R.; Breemen, A.J.J.M. van; Gelinck, G.H.; Janssen, R.A.J.; Kemerink, M.

    2014-01-01

    Organic ferroelectric resistive switches function by grace of nanoscale phase separation in a blend of a semiconducting and a ferroelectric polymer that is sandwiched between metallic electrodes. In this work, various scanning probe techniques are combined with numerical modeling to unravel their

  6. Charge transport in nanoscale vertical organic semiconductor pillar devices

    NARCIS (Netherlands)

    Wilbers, J.G.E.; Xu, B.; Bobbert, P.A.; de Jong, M.P.; van der Wiel, W.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

  7. Development of structural steels for nuclear application

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jun Hwa; Chi, S. H.; Ryu, W. S.; Lee, B. S.; Kim, D. H.; Kim, J. H.; Oh, Y. J.; Byun, T. S.; Yoon, J. H.; Park, D. K.; Oh, J. M.; Cho, H. D.; Kim, H.; Kim, H. D.; Kang, S. S.; Kim, J. W.; Ahn, S. B.

    1997-08-01

    To established the bases of nuclear structural material technologies, this study was focused on the localization and improvement of nuclear structural steels, the production of material property data, and technology developments for integrity evaluation. The important test and analysis technologies for material integrity assessment were developed, and the materials properties of the pressure vessel steels were evaluated systematically on the basis of those technologies, they are microstructural characteristics, tensile and indentation deformation properties, impact properties, and static and dynamic fracture toughness, fatigue and corrosion fatigue etc. Irradiation tests in the research reactors were prepared or completed to obtain the mechanical properties of irradiated materials. The improvement of low alloy steel was also attempted through the comparative study on the manufacturing processes, computer assisted alloy and process design, and application of the inter critical heat treatment. On the other hand, type 304 stainless steels for reactor internals were developed and tested successfully. High strength type 316LN stainless steels for reactor internals were developed and the microstructural characteristics, corrosion resistance, mechanical properties at high temperatures, low cycle fatigue property etc. were tested and analyzed in the view point of the effect of nitrogen. Type 347 stainless steels with high corrosion resistance and toughness for pipings and tubes and low-activated Cr-Mn steels were also developed and their basic properties were evaluated. Finally, the martensitic stainless steels for turbine blade were developed and tests. (author). 242 refs., 100 tabs., 304 figs.

  8. Development of structural steels for nuclear application

    International Nuclear Information System (INIS)

    Hong, Jun Hwa; Chi, S. H.; Ryu, W. S.; Lee, B. S.; Kim, D. H.; Kim, J. H.; Oh, Y. J.; Byun, T. S.; Yoon, J. H.; Park, D. K.; Oh, J. M.; Cho, H. D.; Kim, H.; Kim, H. D.; Kang, S. S.; Kim, J. W.; Ahn, S. B.

    1997-08-01

    To established the bases of nuclear structural material technologies, this study was focused on the localization and improvement of nuclear structural steels, the production of material property data, and technology developments for integrity evaluation. The important test and analysis technologies for material integrity assessment were developed, and the materials properties of the pressure vessel steels were evaluated systematically on the basis of those technologies, they are microstructural characteristics, tensile and indentation deformation properties, impact properties, and static and dynamic fracture toughness, fatigue and corrosion fatigue etc. Irradiation tests in the research reactors were prepared or completed to obtain the mechanical properties of irradiated materials. The improvement of low alloy steel was also attempted through the comparative study on the manufacturing processes, computer assisted alloy and process design, and application of the inter critical heat treatment. On the other hand, type 304 stainless steels for reactor internals were developed and tested successfully. High strength type 316LN stainless steels for reactor internals were developed and the microstructural characteristics, corrosion resistance, mechanical properties at high temperatures, low cycle fatigue property etc. were tested and analyzed in the view point of the effect of nitrogen. Type 347 stainless steels with high corrosion resistance and toughness for pipings and tubes and low-activated Cr-Mn steels were also developed and their basic properties were evaluated. Finally, the martensitic stainless steels for turbine blade were developed and tests. (author). 242 refs., 100 tabs., 304 figs

  9. NeuroLines: A Subway Map Metaphor for Visualizing Nanoscale Neuronal Connectivity

    KAUST Repository

    Al-Awami, Ali K.

    2014-12-31

    We present NeuroLines, a novel visualization technique designed for scalable detailed analysis of neuronal connectivity at the nanoscale level. The topology of 3D brain tissue data is abstracted into a multi-scale, relative distance-preserving subway map visualization that allows domain scientists to conduct an interactive analysis of neurons and their connectivity. Nanoscale connectomics aims at reverse-engineering the wiring of the brain. Reconstructing and analyzing the detailed connectivity of neurons and neurites (axons, dendrites) will be crucial for understanding the brain and its development and diseases. However, the enormous scale and complexity of nanoscale neuronal connectivity pose big challenges to existing visualization techniques in terms of scalability. NeuroLines offers a scalable visualization framework that can interactively render thousands of neurites, and that supports the detailed analysis of neuronal structures and their connectivity. We describe and analyze the design of NeuroLines based on two real-world use-cases of our collaborators in developmental neuroscience, and investigate its scalability to large-scale neuronal connectivity data.

  10. NeuroLines: A Subway Map Metaphor for Visualizing Nanoscale Neuronal Connectivity

    KAUST Repository

    Al-Awami, Ali K.; Beyer, Johanna; Strobelt, Hendrik; Kasthuri, Narayanan; Lichtman, Jeff W.; Pfister, Hanspeter; Hadwiger, Markus

    2014-01-01

    We present NeuroLines, a novel visualization technique designed for scalable detailed analysis of neuronal connectivity at the nanoscale level. The topology of 3D brain tissue data is abstracted into a multi-scale, relative distance-preserving subway map visualization that allows domain scientists to conduct an interactive analysis of neurons and their connectivity. Nanoscale connectomics aims at reverse-engineering the wiring of the brain. Reconstructing and analyzing the detailed connectivity of neurons and neurites (axons, dendrites) will be crucial for understanding the brain and its development and diseases. However, the enormous scale and complexity of nanoscale neuronal connectivity pose big challenges to existing visualization techniques in terms of scalability. NeuroLines offers a scalable visualization framework that can interactively render thousands of neurites, and that supports the detailed analysis of neuronal structures and their connectivity. We describe and analyze the design of NeuroLines based on two real-world use-cases of our collaborators in developmental neuroscience, and investigate its scalability to large-scale neuronal connectivity data.

  11. NeuroLines: A Subway Map Metaphor for Visualizing Nanoscale Neuronal Connectivity.

    Science.gov (United States)

    Al-Awami, Ali K; Beyer, Johanna; Strobelt, Hendrik; Kasthuri, Narayanan; Lichtman, Jeff W; Pfister, Hanspeter; Hadwiger, Markus

    2014-12-01

    We present NeuroLines, a novel visualization technique designed for scalable detailed analysis of neuronal connectivity at the nanoscale level. The topology of 3D brain tissue data is abstracted into a multi-scale, relative distance-preserving subway map visualization that allows domain scientists to conduct an interactive analysis of neurons and their connectivity. Nanoscale connectomics aims at reverse-engineering the wiring of the brain. Reconstructing and analyzing the detailed connectivity of neurons and neurites (axons, dendrites) will be crucial for understanding the brain and its development and diseases. However, the enormous scale and complexity of nanoscale neuronal connectivity pose big challenges to existing visualization techniques in terms of scalability. NeuroLines offers a scalable visualization framework that can interactively render thousands of neurites, and that supports the detailed analysis of neuronal structures and their connectivity. We describe and analyze the design of NeuroLines based on two real-world use-cases of our collaborators in developmental neuroscience, and investigate its scalability to large-scale neuronal connectivity data.

  12. Designing organizational structures: Key thoughts for development.

    Science.gov (United States)

    Killingsworth, Patricia; Eschenbacher, Lynn

    2018-04-01

    Current strategies and concepts to consider in developing a system-level organizational structure for the pharmacy enterprise are discussed. There are many different ways to design an organizational structure for the pharmacy enterprise within a health system. The size of the organization, the number of states in which it operates, and the geographic spread and complexity of the pharmacy business lines should be among the key considerations in determining the optimal organizational and decision-making structures for the pharmacy enterprise. The structure needs to support incorporation of the pharmacy leadership (both system-level executives and local leaders) into all strategic planning and discussions at the hospital and health-system levels so that they can directly represent the pharmacy enterprise instead of relying on others to develop strategy on their behalf. It is important that leaders of all aspects of the pharmacy enterprise report through the system's top pharmacy executive, who should be a pharmacist and have a title consistent with those of other leaders reporting at the same organizational level (e.g., chief pharmacy officer). Pharmacy leaders need to be well positioned within an organization to advocate for the pharmacy enterprise and use all resources to the best of their ability. As the scope and complexity of pharmacy services grow, it is critical to ensure that leadership of the pharmacy enterprise is unified under a single pharmacy executive team. Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  13. Regularities development of entrepreneurial structures in regions

    Directory of Open Access Journals (Sweden)

    Julia Semenovna Pinkovetskaya

    2012-12-01

    Full Text Available Consider regularities and tendencies for the three types of entrepreneurial structures — small enterprises, medium enterprises and individual entrepreneurs. The aim of the research was to confirm the possibilities of describing indicators of aggregate entrepreneurial structures with the use of normal law distribution functions. Presented proposed by the author the methodological approach and results of construction of the functions of the density distribution for the main indicators for the various objects: the Russian Federation, regions, as well as aggregates ofentrepreneurial structures, specialized in certain forms ofeconomic activity. All the developed functions, as shown by the logical and statistical analysis, are of high quality and well-approximate the original data. In general, the proposed methodological approach is versatile and can be used in further studies of aggregates of entrepreneurial structures. The received results can be applied in solving a wide range of problems justify the need for personnel and financial resources at the federal, regional and municipal levels, as well as the formation of plans and forecasts of development entrepreneurship and improvement of this sector of the economy.

  14. Nanoscale Science and Engineering in Romania

    International Nuclear Information System (INIS)

    Dascalu, Dan; Topa, Vladimir; Kleps, Irina

    2001-01-01

    In spite of difficult working conditions and with very low financial support, many groups from Romania are involved in emerging fields, such as the nanoscale science and technology. Until the last years, this activity was developed without a central coordination and without many interactions between these research groups. In the year 2000, some of the institutes and universities active in the nanotechnology field in Romania founded the MICRONANOTECH network. The aim of this paper is to emphasize the main activities and results of the Romanian groups working in this novel domain. Most of the groups are deal with the nanomaterial technology and only few of them have activities in nanostructure science and engineering, in new concepts and device modeling and technology. This paper describes the nanotechnology research development in two of the most significant institutes from Romania: Centre for Nanotechnologies from National Institute for Research and Development in Microtehnologies (IMT-Bucharest) and from National Institute for Research and Development in Materials Physics (INCD-FM), Magurele. The Romanian research results in nanotechnology field were presented in numerous papers presented in international conferences or published in national and international journals. They are also presented in patents, international awards and fellowships. The research effort and financial support are outlined. Some future trends of the Romanian nanoscale science and technology research are also described

  15. Structured illumination microscopy and its new developments

    Directory of Open Access Journals (Sweden)

    Jianling Chen

    2016-05-01

    Full Text Available Optical microscopy allows us to observe the biological structures and processes within living cells. However, the spatial resolution of the optical microscopy is limited to about half of the wavelength by the light diffraction. Structured illumination microscopy (SIM, a type of new emerging super-resolution microscopy, doubles the spatial resolution by illuminating the specimen with a patterned light, and the sample and light source requirements of SIM are not as strict as the other super-resolution microscopy. In addition, SIM is easier to combine with the other imaging techniques to improve their imaging resolution, leading to the developments of diverse types of SIM. SIM has great potential to meet the various requirements of living cells imaging. Here, we review the recent developments of SIM and its combination with other imaging techniques.

  16. Financial Structure and Economic Development in Nigieria

    Directory of Open Access Journals (Sweden)

    Ph. D. Olusegun Olowe

    2012-05-01

    Full Text Available In this study , the measurement of the Nigerian financial interrelation ratio was considered in line with the structure and development of financial system between 1999 and 2008 with a view to examining the incidences of the financial liberalization . The financial intermediation role for Nigeria on current basic prices was computed to determining the extent of stability and /or positive cum negative changes. This is to ensure the involvement of government as well as thedegree of financial institutions’ involvement in the economic growth and development of the country. In essence, the results of this study will be of relevance to formulate and execute policy formulation in its entirety. The result of the study revealed a pure neglect in the country with emphasis on financial intermediation. The earlier we put an enhanced financial structure in place, , the better for the economy.

  17. Nursing Competency: Definition, Structure and Development

    OpenAIRE

    Fukada, Mika

    2018-01-01

    Nursing competency includes core abilities that are required for fulfilling one’s role as a nurse. Therefore, it is important to learly define nursing competency to establish a foundation for nursing education curriculum. However, while the concepts surrounding nursing competency are important for improving nursing quality, they are still not yet completely developed. Thus, challenges remain in establishing finitions and structures for nursing competency, competency levels necessary for nurs...

  18. Scientific methods for developing ultrastable structures

    International Nuclear Information System (INIS)

    Gamble, M.; Thompson, T.; Miller, W.

    1990-01-01

    Scientific methods used by the Los Alamos National Laboratory for developing an ultrastable structure for study of silicon-based elementary particle tracking systems are addressed. In particular, the design, analysis, and monitoring of this system are explored. The development methodology was based on a triad of analytical, computational, and experimental techniques. These were used to achieve a significant degree of mechanical stability (alignment accuracy >1 μrad) and yet allow dynamic manipulation of the system. Estimates of system thermal and vibratory stability and component performance are compared with experimental data collected using laser interferometry and accelerometers. 8 refs., 5 figs., 4 tabs

  19. The human brain. Prenatal development and structure

    International Nuclear Information System (INIS)

    Marin-Padilla, Miguel

    2011-01-01

    This book is unique among the current literature in that it systematically documents the prenatal structural development of the human brain. It is based on lifelong study using essentially a single staining procedure, the classic rapid Golgi procedure, which ensures an unusual and desirable uniformity in the observations. The book is amply illustrated with 81 large, high-quality color photomicrographs never previously reproduced. These photomicrographs, obtained at 6, 7, 11, 15, 18, 20, 25, 30, 35, and 40 weeks of gestation, offer a fascinating insight into the sequential prenatal development of neurons, blood vessels, and glia in the human brain. (orig.)

  20. The human brain. Prenatal development and structure

    Energy Technology Data Exchange (ETDEWEB)

    Marin-Padilla, Miguel

    2011-07-01

    This book is unique among the current literature in that it systematically documents the prenatal structural development of the human brain. It is based on lifelong study using essentially a single staining procedure, the classic rapid Golgi procedure, which ensures an unusual and desirable uniformity in the observations. The book is amply illustrated with 81 large, high-quality color photomicrographs never previously reproduced. These photomicrographs, obtained at 6, 7, 11, 15, 18, 20, 25, 30, 35, and 40 weeks of gestation, offer a fascinating insight into the sequential prenatal development of neurons, blood vessels, and glia in the human brain. (orig.)

  1. Phototoxicity and Dosimetry of Nano-scale Titanium Dioxide in Aquatic Organisms

    Science.gov (United States)

    We have been testing nanoscale TiO2 (primarily Evonik P25) in acute exposures to identify and quantify its phototoxicity under solar simulated radiation (SSR), and to develop dose metrics reflective of both nano-scale properties and the photon component of its potency. Several e...

  2. Abnormal arrangement of a collagen/apatite extracellular matrix orthogonal to osteoblast alignment is constructed by a nanoscale periodic surface structure.

    Science.gov (United States)

    Matsugaki, Aira; Aramoto, Gento; Ninomiya, Takafumi; Sawada, Hiroshi; Hata, Satoshi; Nakano, Takayoshi

    2015-01-01

    Morphological and directional alteration of cells is essential for structurally appropriate construction of tissues and organs. In particular, osteoblast alignment is crucial for the realization of anisotropic bone tissue microstructure. In this article, the orientation of a collagen/apatite extracellular matrix (ECM) was established by controlling osteoblast alignment using a surface geometry with nanometer-sized periodicity induced by laser ablation. Laser irradiation induced self-organized periodic structures (laser-induced periodic surface structures; LIPSS) with a spatial period equal to the wavelength of the incident laser on the surface of biomedical alloys of Ti-6Al-4V and Co-Cr-Mo. Osteoblast orientation was successfully induced parallel to the grating structure. Notably, both the fibrous orientation of the secreted collagen matrix and the c-axis of the produced apatite crystals were orientated orthogonal to the cell direction. To the best of our knowledge, this is the first report demonstrating that bone tissue anisotropy is controllable, including the characteristic organization of a collagen/apatite composite orthogonal to the osteoblast orientation, by controlling the cell alignment using periodic surface geometry. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. A nanoscale bio-inspired light-harvesting system developed from self-assembled alkyl-functionalized metallochlorin nano-aggregates

    KAUST Repository

    Ocakoǧlu, Kasim; Joya, Khurram Saleem; Harputlu, Ersan; Tarnowska, Anna; Gryko, Daniel T.

    2014-01-01

    Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C 18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The transparent Zn-chlorin nano-aggregates inside the alkyl-TiO2 modified AAO nano-channels have a diameter of ∼120 nm in a 60 μm length channel. UV-Vis studies and fluorescence emission spectra further confirm the formation of the supramolecular ZnChl aggregates from monomer molecules inside the alkyl-functionalized nano-channels. Our results prove that the novel and unique method can be used to produce efficient and stable light-harvesting assemblies for effective solar energy capture through transparent and stable nano-channel ceramic materials modified with bio-mimetic molecular self-assembled nano-aggregates. © 2014 the Partner Organisations.

  4. Simulation of capillary bridges between nanoscale particles.

    Science.gov (United States)

    Dörmann, Michael; Schmid, Hans-Joachim

    2014-02-04

    Capillary forces are very important as they exceed in general other adhesion forces. But at the same time the exact calculation of these forces is very complex, so often assumptions and approximations are used. Previous research was done with regard to micrometer sized particles, but the behavior of nanoscale particles is different. Hence, the results for micrometer sized particles cannot be directly transferred when considering nanoscale particles. Therefore, a simulation method was developed to calculate numerically the shape of a rotationally symmetrical capillary bridge between two spherical particles or a particle and a plate. The capillary bridge in the gap between the particles is formed due to capillary condensation and is in thermodynamic equilibrium with the gas phase. Hence the Kelvin equation and the Young-Laplace equation can be used to calculate the profile of the capillary bridge, depending on the relative humidity of the surrounding air. The bridge profile consists of several elements that are determined consecutively and interpolated linearly. After the shape is determined, the volume and force, divided into capillary pressure force and surface tension force, can be calculated. The validation of this numerical model will be shown by comparison with several different analytical calculations for micrometer-sized particles. Furthermore, it is demonstrated that two often used approximations, (1) the toroidal approximation and (2) the use of an effective radius, cannot be used for nanoscale particles without remarkable mistake. It will be discussed how the capillary force and its components depend on different parameters, like particle size, relative humidity, contact angle, and distance, respectively. The rupture of a capillary bridge due to particle separation will also be presented.

  5. Development of an active structure flight experiment

    Science.gov (United States)

    Manning, R. A.; Wyse, R. E.; Schubert, S. R.

    1993-02-01

    The design and development of the Air Force and TRW's Advanced Control Technology Experiment (ACTEX) flight experiment is described in this paper. The overall objective of ACTEX is to provide an active structure trailblazer which will demonstrate the compatibility of active structures with operational spacecraft performance and lifetime measures. At the heart of the experiment is an active tripod driven by a digitally-programmable analog control electronics subsystem. Piezoceramic sensors and actuators embedded in a graphite epoxy host material provide the sensing and actuation mechanism for the active tripod. Low noise ground-programmable electronics provide a virtually unlimited number of control schemes that can be implemented in the space environment. The flight experiment program provides the opportunity to gather performance, reliability, adaptability, and lifetime performance data on vibration suppression hardware for the next generation of DoD and NASA spacecraft.

  6. Improving Neural Recording Technology at the Nanoscale

    Science.gov (United States)

    Ferguson, John Eric

    Neural recording electrodes are widely used to study normal brain function (e.g., learning, memory, and sensation) and abnormal brain function (e.g., epilepsy, addiction, and depression) and to interface with the nervous system for neuroprosthetics. With a deep understanding of the electrode interface at the nanoscale and the use of novel nanofabrication processes, neural recording electrodes can be designed that surpass previous limits and enable new applications. In this thesis, I will discuss three projects. In the first project, we created an ultralow-impedance electrode coating by controlling the nanoscale texture of electrode surfaces. In the second project, we developed a novel nanowire electrode for long-term intracellular recordings. In the third project, we created a means of wirelessly communicating with ultra-miniature, implantable neural recording devices. The techniques developed for these projects offer significant improvements in the quality of neural recordings. They can also open the door to new types of experiments and medical devices, which can lead to a better understanding of the brain and can enable novel and improved tools for clinical applications.

  7. A nanoscale bio-inspired light-harvesting system developed from self-assembled alkyl-functionalized metallochlorin nano-aggregates

    Science.gov (United States)

    Ocakoglu, Kasim; Joya, Khurram S.; Harputlu, Ersan; Tarnowska, Anna; Gryko, Daniel T.

    2014-07-01

    Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The transparent Zn-chlorin nano-aggregates inside the alkyl-TiO2 modified AAO nano-channels have a diameter of ~120 nm in a 60 μm length channel. UV-Vis studies and fluorescence emission spectra further confirm the formation of the supramolecular ZnChl aggregates from monomer molecules inside the alkyl-functionalized nano-channels. Our results prove that the novel and unique method can be used to produce efficient and stable light-harvesting assemblies for effective solar energy capture through transparent and stable nano-channel ceramic materials modified with bio-mimetic molecular self-assembled nano-aggregates.Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The

  8. System reliability developments in structural engineering

    International Nuclear Information System (INIS)

    Moses, F.

    1982-01-01

    Two major limitations occur in present structural design code developments utilizing reliability theory. The notional system reliabilities may differ significantly from calibrated component reliabilities. Secondly, actual failures are often due to gross errors not reflected in most present code formats. A review is presented of system reliability methods and further new concepts are developed. The incremental load approach for identifying and expressing collapse modes is expanded by employing a strategy to identify and enumerate the significant structural collapse modes. It further isolates the importance of critical components in the system performance. Ductile and brittle component behavior and strength correlation is reflected in the system model and illustrated in several examples. Modal combinations for the system reliability are also reviewed. From these developments a system factor can be addended to component safety checking equations. Values may be derived from system behavior by substituting in a damage model which accounts for the response range from component failure to collapse. Other strategies are discussed which emphasize quality assurance during design and in-service inspection for components whose behavior is critical to the system reliability. (Auth.)

  9. Fast three-dimensional nanoscale metrology in dual-beam FIB-SEM instrumentation

    International Nuclear Information System (INIS)

    Repetto, Luca; Buzio, Renato; Denurchis, Carlo; Firpo, Giuseppe; Piano, Emanuele; Valbusa, Ugo

    2009-01-01

    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.

  10. Creating nanoscale emulsions using condensation.

    Science.gov (United States)

    Guha, Ingrid F; Anand, Sushant; Varanasi, Kripa K

    2017-11-08

    Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.

  11. Coded nanoscale self-assembly

    Indian Academy of Sciences (India)

    to research in the generation of materials with controlled microstructural charac- teristics. In an effort to sustain and further such innovative developments, it is ... of molecules) under thermodynamic equilibrium conditions into structurally well-.

  12. Puberty and structural brain development in humans.

    Science.gov (United States)

    Herting, Megan M; Sowell, Elizabeth R

    2017-01-01

    Adolescence is a transitional period of physical and behavioral development between childhood and adulthood. Puberty is a distinct period of sexual maturation that occurs during adolescence. Since the advent of magnetic resonance imaging (MRI), human studies have largely examined neurodevelopment in the context of age. A breadth of animal findings suggest that sex hormones continue to influence the brain beyond the prenatal period, with both organizational and activational effects occurring during puberty. Given the animal evidence, human MRI research has also set out to determine how puberty may influence otherwise known patterns of age-related neurodevelopment. Here we review structural-based MRI studies and show that pubertal maturation is a key variable to consider in elucidating sex- and individual- based differences in patterns of human brain development. We also highlight the continuing challenges faced, as well as future considerations, for this vital avenue of research. Copyright © 2016. Published by Elsevier Inc.

  13. Plant virus directed fabrication of nanoscale materials and devices

    Science.gov (United States)

    2015-03-26

    Structural features within the internal and external PVN surfaces are amenable to either chemi- cal or genetic modifications for the display of novel moieties...structures: from nanoboomerangs to tetrapods. Nanoscale 7, 344–355. Eggen, R., Verver, J., Wellink, J., De Jong, A., Goldbach, R., van Kammen, A., 1989...in planta expression and for templates for synthetic biology applica- tions. New Phytol. 200, 16–26. Saunders, K., Sainsbury, F., Lomonossoff, G.P

  14. Local and Nanoscale Structure and Speciation in the PuO{sub 2+x-y}(OH){sub 2y} {center_dot}zH{sub 2}O System

    Energy Technology Data Exchange (ETDEWEB)

    Conradson, Steven D.; Begg, Bruce D.; Clark, David L.; Den Auwer, Christophe J.; Ding, Mei; Dorhout, Peter K.; Espinosa-Faller, Francisco J.; Gordon, Pamela L.; Haire, Richard G.; Hess, Nancy J.; Hess, Ryan F.; Keogh, D. Webster; Morales, Luis A.; Neu, Mary P.; Paviet-Hartmann, Patricia; Runde, Wolfgang; Tait, C DREW.; Veirs, D. Kirk; Villella, Phillip M.

    2004-09-26

    Pu L3 X-ray absorption fine structure spectra from 24 samples of PuO{sub 2+x} (and two related Pu substituted oxides), prepared by a variety of methods, demonstrate that (1) although the Pu sublattice remains the ordered part of the Pu distribution, the nearest-neighbor O atoms even at x = 0 are found in a multisite distribution with Pu-O distances consistent with the stable incorporation of OH{sup -} (and possibly H{sub 2}O and H{sup +}) into the PuO{sub 2} lattice; (2) the excess O from oxidation is found at Pu-O distances <1.9 {angstrom}, consistent with the multiply bound ''oxo''-type ligands found in molecular complexes of Pu(V) and Pu(VI); (3) the Pu associated with these oxo groups is most likely Pu(V), so that the excess O probably occurs as PuO{sub 2}{sup +} moieties that are aperiodically distributed through the lattice; and (4) the collective interactions between these defect sites most likely cause them to cluster so as give nanoscale heterogeneity in the form of domains that may have unusual reactivity, observed as sequential oxidation by H{sub 2}O at ambient conditions. The most accurate description of PuO{sub 2} is therefore actually PuO{sub 2+x-y}(OH){sub 2y} {center_dot} zH{sub 2}O, with pure, ordered, homogeneous PuO{sub 2} attained only when H{sub 2}O is rigorously excluded and the O activity is relatively low.

  15. Nanoscale thermoelectric materials

    International Nuclear Information System (INIS)

    Failamani, F.

    2015-01-01

    Thermoelectric (TE) materials directly convert thermal energy to electrical energy when subjected to a temperature gradient, whereas if electricity is applied to thermoelectric materials, a temperature gradient is formed. The performance of thermoelectric materials is characterized by a dimensionless figure of merit (ZT = S2T/ρλ), which consists of three parameters, Seebeck coefficient (S), electrical resistivity (ρ) and thermal conductivity (λ). To achieve good performance of thermoelectric power generation and cooling, ZT's of thermoelectric materials must be as high as possible, preferably above unity. This thesis comprises three main parts, which are distributed into six chapters: (i) nanostructuring to improve TE performance of trivalent rare earth-filled skutterudites (chapter 1 and 2), (ii) interactions of skutterudite thermolectrics with group V metals as potential electrode or diffusion barrier for TE devices (chapter 3 and 4), and (iii) search for new materials for TE application (chapter 5 and 6). Addition of secondary phases, especially nano sized phases can cause additional reduction of the thermal conductivity of a filled skutterudite which improves the figure of merit (ZT) of thermoelectric materials. In chapter 1 we investigated the effect of various types of secondary phases (silicides, borides, etc.) on the TE properties of trivalent rare earth filled Sb-based skutterudites as commercially potential TE materials. In this context the possibilty to introduce borides as nano-particles (via ball-milling in terms of a skutterudite/boride composite) is also elucidated in chapter 2. As a preliminary study, crystal structure of novel high temperature FeB-type phases found in the ternary Ta-{Ti,Zr,Hf,}-B systems were investigated. In case of Ti and Hf this phase is the high temperature stabilization of binary group IV metal monoborides, whereas single crystal study of (Ta,Zr)B proves that it is a true ternary phase as no stable monoboride exist in the

  16. Photoresponsive smart surface of LC azo-dendrimer: photomanipulation of topological structures and real-time imaging at a nano-scale

    Science.gov (United States)

    Araoka, Fumito; Eremin, Alexey; Aya, Satoshi; Lee, Guksik; Ito, Atsuki; Nadasi, Hajnalka; Sebastian, Nerea; Ishikawa, Ken; Haba, Osamu; Stannarius, Ralf; Yonetake, Koichiro; Takezoe, Hideo

    2017-02-01

    In this paper, we review some results on our recent studies on photo-induced phenomena of liquid crystals (LCs) by means of interfaces decorated with a photo-responsive azobenzene dendrimer (azo-dendrimer). The azo-dendrimer molecules doped in a LC are spontaneously segregated from bulk and adsorbed onto substrate/LC or solvent/LC interfaces, and their photo-isomerization can bring about the so-called anchoring transition, i.e. reversible switching between homeotropic and planar alignment states of the bulk LC, when exposed to UV/VIS light. In addition to photoinduced anchoring transition in a LC cell, several interesting photo-induced phenomena through the azo-dendrimerdecorated interfaces have been reported, such as photo-induced transformation of the interior topological structures of nematic, cholesteric and smectic droplets, photo-mechanical motion of the micro particles dispersed in a nematic matrix, and optical assistance of the athermal anchoring transition with the aid of a perfluoropolymer surface. In addition to such phenomena, we also discuss the conditions of such photo-responsive interfaces in terms of the polar anchoring energy at the interface upon photo-isomerization under illumination of UV and/or VIS lights. The anisotropy of the polar anchoring energy was evaluated experimentally by means of Polarization Microscopy (POM), Dielectric Spectroscopy (DS), Second Harmonic Generation (SHG), and Attenuated Total Reflection Fourier Transform Infrared (ATR-IR) Spectroscopy, and theoretically based on the simple Rapini-Papoular model. We also demonstrate the continuous bulk orientation change by the photo-dynamic process through the fine control of the polar anchoring energy. Besides, the state-of-the-art video-rate atomic force microscopy (ν-AFM) was carried out to visualize the dynamics of such interfaces at a nano-meter scale.

  17. Catalysis at the nanoscale may change selectivity.

    Science.gov (United States)

    Costentin, Cyrille; Savéant, Jean-Michel

    2016-10-18

    Among the many virtues ascribed to catalytic nanoparticles, the prospect that the passage from the macro- to the nanoscale may change product selectivity attracts increasing attention. To date, why such effects may exist lacks explanation. Guided by recent experimental reports, we propose that the effects may result from the coupling between the chemical steps in which the reactant, intermediates, and products are involved and transport of these species toward the catalytic surface. Considering as a thought experiment the competitive formation of hydrogen and formate upon reduction of hydrogenocarbonate ions on metals like palladium or platinum, a model is developed that allows one to identify the governing parameters and predict the effect of nanoscaling on selectivity. The model leads to a master equation relating product selectivity and thickness of the diffusion layer. The latter parameter varies considerably upon passing from the macro- to the nanoscale, thus predicting considerable variations of product selectivity. These are subtle effects in the sense that the same mechanism might exhibit a reverse variation of the selectivity if the set of parameter values were different. An expression is given that allows one to predict the direction of the effect. There has been a tendency to assign the catalytic effects of nanoscaling to chemical reactivity changes of the active surface. Such factors might be important in some circumstances. We, however, insist on the likely role of short-distance transport on product selectivity, which could have been thought, at first sight, as the exclusive domain of chemical factors.

  18. 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.

  19. Fabrication of Single, Vertically Aligned Carbon Nanotubes in 3D Nanoscale Architectures

    Science.gov (United States)

    Kaul, Anupama B.; Megerian, Krikor G.; Von Allmen, Paul A.; Baron, Richard L.

    2010-01-01

    Plasma-enhanced chemical vapor deposition (PECVD) and high-throughput manufacturing techniques for integrating single, aligned carbon nanotubes (CNTs) into novel 3D nanoscale architectures have been developed. First, the PECVD growth technique ensures excellent alignment of the tubes, since the tubes align in the direction of the electric field in the plasma as they are growing. Second, the tubes generated with this technique are all metallic, so their chirality is predetermined, which is important for electronic applications. Third, a wafer-scale manufacturing process was developed that is high-throughput and low-cost, and yet enables the integration of just single, aligned tubes with nanoscale 3D architectures with unprecedented placement accuracy and does not rely on e-beam lithography. Such techniques should lend themselves to the integration of PECVD grown tubes for applications ranging from interconnects, nanoelectromechanical systems (NEMS), sensors, bioprobes, or other 3D electronic devices. Chemically amplified polyhydroxystyrene-resin-based deep UV resists were used in conjunction with excimer laser-based (lambda = 248 nm) step-and-repeat lithography to form Ni catalyst dots = 300 nm in diameter that nucleated single, vertically aligned tubes with high yield using dc PECVD growth. This is the first time such chemically amplified resists have been used, resulting in the nucleation of single, vertically aligned tubes. In addition, novel 3D nanoscale architectures have been created using topdown techniques that integrate single, vertically aligned tubes. These were enabled by implementing techniques that use deep-UV chemically amplified resists for small-feature-size resolution; optical lithography units that allow unprecedented control over layer-to-layer registration; and ICP (inductively coupled plasma) etching techniques that result in near-vertical, high-aspect-ratio, 3D nanoscale architectures, in conjunction with the use of materials that are

  20. Choosing mineral carrier of nanoscale additives for asphalt concrete

    Directory of Open Access Journals (Sweden)

    Inozemtsev Sergey Sergeevich

    2014-03-01

    Full Text Available At present time the operation life of the majority of roads is essentially shorter than required. The reason for it is the increase in traffic intensity and axle loads of automobile transport. The obvious reasons for early wear of roads are the low quality of the components used and low industrial standards while producing asphalt pavement. In this paper the mineral material was selected as a carrier of nanoscale additives for asphalt. The optimal modes for grinding mineral materials were identified, which provide correspondence of their structure parameters with the developed model. The influence of different mineral nanomodifier carriers on the structure formation processes was estimated. It is shown that among a number of mineral materials diatomite has high activity in relation to the bitumen, because it has a highly porous structure. It is also shown that as a result of lighter fractions of bitumen adsorption on the border of phase interface, diatomite and bitumen changes from the free state to the film, and solvate shell of bitumen is saturated with asphaltenes. With the help of IR spectroscopy the authors defined the nature of the diatomite and bitumen interaction and proved that in the process of their interaction there occurs physical adsorption with additional absorption of bitumen components into the pore space of diatomite grains.

  1. Nanoscale hydrodynamics near solids

    Science.gov (United States)

    Camargo, Diego; de la Torre, J. A.; Duque-Zumajo, D.; Español, Pep; Delgado-Buscalioni, Rafael; Chejne, Farid

    2018-02-01

    Density Functional Theory (DFT) is a successful and well-established theory for the study of the structure of simple and complex fluids at equilibrium. The theory has been generalized to dynamical situations when the underlying dynamics is diffusive as in, for example, colloidal systems. However, there is no such a clear foundation for Dynamic DFT (DDFT) for the case of simple fluids in contact with solid walls. In this work, we derive DDFT for simple fluids by including not only the mass density field but also the momentum density field of the fluid. The standard projection operator method based on the Kawasaki-Gunton operator is used for deriving the equations for the average value of these fields. The solid is described as featureless under the assumption that all the internal degrees of freedom of the solid relax much faster than those of the fluid (solid elasticity is irrelevant). The fluid moves according to a set of non-local hydrodynamic equations that include explicitly the forces due to the solid. These forces are of two types, reversible forces emerging from the free energy density functional, and accounting for impenetrability of the solid, and irreversible forces that involve the velocity of both the fluid and the solid. These forces are localized in the vicinity of the solid surface. The resulting hydrodynamic equations should allow one to study dynamical regimes of simple fluids in contact with solid objects in isothermal situations.

  2. The primate fovea: Structure, function and development.

    Science.gov (United States)

    Bringmann, Andreas; Syrbe, Steffen; Görner, Katja; Kacza, Johannes; Francke, Mike; Wiedemann, Peter; Reichenbach, Andreas

    2018-03-30

    A fovea is a pitted invagination in the inner retinal tissue (fovea interna) that overlies an area of photoreceptors specialized for high acuity vision (fovea externa). Although the shape of the vertebrate fovea varies considerably among the species, there are two basic types. The retina of many predatory fish, reptilians, and birds possess one (or two) convexiclivate fovea(s), while the retina of higher primates contains a concaviclivate fovea. By refraction of the incoming light, the convexiclivate fovea may function as image enlarger, focus indicator, and movement detector. By centrifugal displacement of the inner retinal layers, which increases the transparency of the central foveal tissue (the foveola), the primate fovea interna improves the quality of the image received by the central photoreceptors. In this review, we summarize ‒ with the focus on Müller cells of the human and macaque fovea ‒ data regarding the structure of the primate fovea, discuss various aspects of the optical function of the fovea, and propose a model of foveal development. The "Müller cell cone" of the foveola comprises specialized Müller cells which do not support neuronal activity but may serve optical and structural functions. In addition to the "Müller cell cone", structural stabilization of the foveal morphology may be provided by the 'z-shaped' Müller cells of the fovea walls, via exerting tractional forces onto Henle fibers. The spatial distribution of glial fibrillary acidic protein may suggest that the foveola and the Henle fiber layer are subjects to mechanical stress. During development, the foveal pit is proposed to be formed by a vertical contraction of the centralmost Müller cells. After widening of the foveal pit likely mediated by retracting astrocytes, Henle fibers are formed by horizontal contraction of Müller cell processes in the outer plexiform layer and the centripetal displacement of photoreceptors. A better understanding of the molecular, cellular

  3. In-situ X-ray absorption spectroscopy analysis of capacity fade in nanoscale-LiCoO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Patridge, Christopher J. [NRC/NRL Cooperative Research Associate, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Love, Corey T., E-mail: corey.love@nrl.navy.mil [Chemistry Division, Code 6113, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Swider-Lyons, Karen E. [Chemistry Division, Code 6113, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Twigg, Mark E. [Electronics Science and Technology Division, Code 6812, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Ramaker, David E. [Chemistry Division, Code 6189, U.S. Naval Research laboratory, Washington, DC 20375 (United States)

    2013-07-15

    The local structure of nanoscale (∼10–40 nm) LiCoO{sub 2} is monitored during electrochemical cycling utilizing in-situ X-ray absorption spectroscopy (XAS). The high surface area of the LiCoO{sub 2} nanoparticles not only enhances capacity fade, but also provides a large signal from the particle surface relative to the bulk. Changes in the nanoscale LiCoO{sub 2} metal-oxide bond lengths, structural disorder, and chemical state are tracked during cycling by adapting the delta mu (Δμ) technique in complement with comprehensive extended X-ray absorption fine structure (EXAFS) modeling. For the first time, we use a Δμ EXAFS method, and by comparison of the difference EXAFS spectra, extrapolate significant coordination changes and reduction of cobalt species with cycling. This combined approach suggests Li–Co site exchange at the surface of the nanoscale LiCoO{sub 2} as a likely factor in the capacity fade and irreversible losses in practical, microscale LiCoO{sub 2}. - Graphical abstract: Electrochemical cycling of Li-ion batteries has strong impact on the structure and integrity of the cathode active material particularly near the surface/electrolyte interface. In developing a new method, we have used in-situ X-ray absorption spectroscopy during electrochemical cycling of nanoscale LiCoO{sub 2} to track changes during charge and discharge and between subsequent cycles. Using difference spectra, several small changes in Co-O bond length, Co-O and Co-Co coordination, and site exchange between Co and Li sites can be tracked. These methods show promise as a new technique to better understand processes which lead to capacity fade and loss in Li-ion batteries. - Highlights: • A new method is developed to understand capacity fade in Li-ion battery cathodes. • Structural changes are tracked during Li intercalation/deintercalation of LiCoO{sub 2}. • Surface structural changes are emphasized using nanoscale-LiCoO{sub 2} and difference spectra. • Full multiple

  4. In-situ X-ray absorption spectroscopy analysis of capacity fade in nanoscale-LiCoO2

    International Nuclear Information System (INIS)

    Patridge, Christopher J.; Love, Corey T.; Swider-Lyons, Karen E.; Twigg, Mark E.; Ramaker, David E.

    2013-01-01

    The local structure of nanoscale (∼10–40 nm) LiCoO 2 is monitored during electrochemical cycling utilizing in-situ X-ray absorption spectroscopy (XAS). The high surface area of the LiCoO 2 nanoparticles not only enhances capacity fade, but also provides a large signal from the particle surface relative to the bulk. Changes in the nanoscale LiCoO 2 metal-oxide bond lengths, structural disorder, and chemical state are tracked during cycling by adapting the delta mu (Δμ) technique in complement with comprehensive extended X-ray absorption fine structure (EXAFS) modeling. For the first time, we use a Δμ EXAFS method, and by comparison of the difference EXAFS spectra, extrapolate significant coordination changes and reduction of cobalt species with cycling. This combined approach suggests Li–Co site exchange at the surface of the nanoscale LiCoO 2 as a likely factor in the capacity fade and irreversible losses in practical, microscale LiCoO 2 . - Graphical abstract: Electrochemical cycling of Li-ion batteries has strong impact on the structure and integrity of the cathode active material particularly near the surface/electrolyte interface. In developing a new method, we have used in-situ X-ray absorption spectroscopy during electrochemical cycling of nanoscale LiCoO 2 to track changes during charge and discharge and between subsequent cycles. Using difference spectra, several small changes in Co-O bond length, Co-O and Co-Co coordination, and site exchange between Co and Li sites can be tracked. These methods show promise as a new technique to better understand processes which lead to capacity fade and loss in Li-ion batteries. - Highlights: • A new method is developed to understand capacity fade in Li-ion battery cathodes. • Structural changes are tracked during Li intercalation/deintercalation of LiCoO 2 . • Surface structural changes are emphasized using nanoscale-LiCoO 2 and difference spectra. • Full multiple scattering calculations are used to

  5. Recent developments of nano-structured materials as the catalysts for oxygen reduction reaction

    Science.gov (United States)

    Kang, SungYeon; Kim, HuiJung; Chung, Yong-Ho

    2018-04-01

    Developments of high efficient materials for electrocatalyst are significant topics of numerous researches since a few decades. Recent global interests related with energy conversion and storage lead to the expansion of efforts to find cost-effective catalysts that can substitute conventional catalytic materials. Especially, in the field of fuel cell, novel materials for oxygen reduction reaction (ORR) have been noticed to overcome disadvantages of conventional platinum-based catalysts. Various approaching methods have been attempted to achieve low cost and high electrochemical activity comparable with Pt-based catalysts, including reducing Pt consumption by the formation of hybrid materials, Pt-based alloys, and not-Pt metal or carbon based materials. To enhance catalytic performance and stability, numerous methods such as structural modifications and complex formations with other functional materials are proposed, and they are basically based on well-defined and well-ordered catalytic active sites by exquisite control at nanoscale. In this review, we highlight the development of nano-structured catalytic materials for ORR based on recent findings, and discuss about an outlook for the direction of future researches.

  6. Designing pseudocubic perovskites with enhanced nanoscale polarization

    Energy Technology Data Exchange (ETDEWEB)

    Levin, I. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA; Laws, W. J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA; Wang, D. [Department of Materials Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom; Reaney, I. M. [Department of Materials Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom

    2017-11-20

    A crystal-chemical framework has been proposed for the design of pseudocubic perovskites with nanoscale ferroelectric order, and its applicability has been demonstrated using a series of representative solid solutions that combined ferroelectric (K0.5Bi0.5TiO3, BaTiO3, and PbTiO3) and antiferroelectric (Nd-substituted BiFeO3) end members. The pseudocubic structures obtained in these systems exhibited distortions that were coherent on a scale ranging from sub-nanometer to tens of nanometers, but, in all cases, the macroscopic distortion remained unresolvable even if using high-resolution X-ray powder diffraction. Different coherence lengths for the local atomic displacements account for the distinctly different dielectric, ferroelectric, and electromechanical properties exhibited by the samples. The guidelines identified provide a rationale for chemically tuning the coherence length to obtain the desired functional response.

  7. 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.

  8. Structural Connectivity of the Developing Human Amygdala

    Science.gov (United States)

    Saygin, Zeynep M.; Osher, David E.; Koldewyn, Kami; Martin, Rebecca E.; Finn, Amy; Saxe, Rebecca; Gabrieli, John D.E.; Sheridan, Margaret

    2015-01-01

    A large corpus of research suggests that there are changes in the manner and degree to which the amygdala supports cognitive and emotional function across development. One possible basis for these developmental differences could be the maturation of amygdalar connections with the rest of the brain. Recent functional connectivity studies support this conclusion, but the structural connectivity of the developing amygdala and its different nuclei remains largely unstudied. We examined age related changes in the DWI connectivity fingerprints of the amygdala to the rest of the brain in 166 individuals of ages 5-30. We also developed a model to predict age based on individual-subject amygdala connectivity, and identified the connections that were most predictive of age. Finally, we segmented the amygdala into its four main nucleus groups, and examined the developmental changes in connectivity for each nucleus. We observed that with age, amygdalar connectivity becomes increasingly sparse and localized. Age related changes were largely localized to the subregions of the amygdala that are implicated in social inference and contextual memory (the basal and lateral nuclei). The central nucleus’ connectivity also showed differences with age but these differences affected fewer target regions than the basal and lateral nuclei. The medial nucleus did not exhibit any age related changes. These findings demonstrate increasing specificity in the connectivity patterns of amygdalar nuclei across age. PMID:25875758

  9. Development of all-beryllium riveted structures

    International Nuclear Information System (INIS)

    Floyd, D.R.; Leslie, W.W.; Miley, D.V.; Nokes, R.W.

    1976-01-01

    Results are presented of a development program aimed at making a full-scale, all-beryllium frustrum by riveted assembly methods. Included are descriptions of the sheet-metal fabrication practices and assembly plans. Results of extensive mechanical testing of both ingot- and powder-source beryllium products that are presented include tensile, notch-tensile, bearing, and shear tests. Although the full-size structure has not been built, examples are given of several conical and cylindrical structures that were made. The largest of these is a 20-in. diameter, 15-in. long cylinder that was roll-formed from one 0.050-in. thick ingot sheet and assembled with 60 countersunk rivets. Tensile testing of riveted flat coupons is also reported as is bulge testing of riveted cylindrical shells. A cost comparison of riveted deep-drawn and powder-source cylinders is made. Results show that when strength and dimensional tolerance requirements are not severe, a riveted assembly approach is warranted. 33 figures, 8 tables

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. A surface evolution scheme to identify nanoscale intrinsic geometry from AFM experimental data

    International Nuclear Information System (INIS)

    Jang, Hong-Lae; Kim, Hyun-Seok; Park, Youmie; Cho, Seonho

    2013-01-01

    The geometrical properties of metallic nanoparticles such as the size and morphology have significant impacts on the structure and stability of the adsorbed biological entities as well as the nanoscale structural performances. To identify the nanoscale intrinsic geometry from the height images by atomic force microscopy (AFM), we developed a curvature-dependent evolution scheme that can eliminate the noise and smoothen the surfaces. The principal curvatures are computed directly from the first and second derivatives of the discrete AFM height data. The principal curvatures and directions correspond to the eigenvalues and eigenvectors of shape operator matrix, respectively. The evolution equation using the principal curvature flows smoothens the images in the corresponding principal directions. For an idealized model, κ 2 flow successfully identifies the major valley lines to represent the boundary of nanoparticles without referring to the phase information, whereas the mean curvature flow eliminates all the minor ones leaving only the major feature of the boundary. To demonstrate the capability of noise removal, smoothing surfaces, the identification of ridge and valley lines, and the extraction of intrinsic geometry, the developed numerical scheme is applied to real AFM data that include the silver nanoparticles of 24 nm diameter and the gold nanoparticles of 33–56 nm diameters

  15. Direct Probing of Polarization Charge at Nanoscale Level

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Owoong [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering; Seol, Daehee [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering; Lee, Dongkyu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Han, Hee [Korea Research Inst. of Standards and Science (KRISS), Daejeon (South Korea); Lindfors-Vrejoiu, Ionela [Univ. of Cologne (Germany). Physics Inst.; Lee, Woo [Korea Research Inst. of Standards and Science (KRISS), Daejeon (South Korea); Jesse, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Lee, Ho Nyung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Kalinin, Sergei V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Alexe, Marin [Univ. of Warwick, Coventry (United Kingdom). Dept. of Physics; Kim, Yunseok [Sungkyunkwan Univ., Suwon (Republic of Korea). School of Advanced Materials and Engineering

    2017-11-14

    Ferroelectric materials possess spontaneous polarization that can be used for multiple applications. Owing to a long-term development of reducing the sizes of devices, the preparation of ferroelectric materials and devices is entering the nanometer-scale regime. In order to evaluate the ferroelectricity, there is a need to investigate the polarization charge at the nanoscale. Nonetheless, it is generally accepted that the detection of polarization charges using a conventional conductive atomic force microscopy (CAFM) without a top electrode is not feasible because the nanometer-scale radius of an atomic force microscopy (AFM) tip yields a very low signal-to-noise ratio. But, the detection is unrelated to the radius of an AFM tip and, in fact, a matter of the switched area. In this work, the direct probing of the polarization charge at the nanoscale is demonstrated using the positive-up-negative-down method based on the conventional CAFM approach without additional corrections or circuits to reduce the parasitic capacitance. The polarization charge densities of 73.7 and 119.0 µC cm-2 are successfully probed in ferroelectric nanocapacitors and thin films, respectively. The results we obtained show the feasibility of the evaluation of polarization charge at the nanoscale and provide a new guideline for evaluating the ferroelectricity at the nanoscale.

  16. Engineering Platinum Alloy Electrocatalysts in Nanoscale for PEMFC Application

    Energy Technology Data Exchange (ETDEWEB)

    He, Ting [Idaho National Laboratory

    2016-03-01

    Fuel cells are expected to be a key next-generation energy source used for vehicles and homes, offering high energy conversion efficiency and minimal pollutant emissions. However, due to large overpotentials on anode and cathode, the efficiency is still much lower than theoretically predicted. During the past decades, considerable efforts have been made to investigate synergy effect of platinum alloyed with base metals. But, engineering the alloy particles in nanoscale has been a challenge. Most important challenges in developing nanostructured materials are the abilities to control size, monodispersity, microcomposition, and even morphology or self-assembly capability, so called Nanomaterials-by-Design, which requires interdisciplinary collaborations among computational modeling, chemical synthesis, nanoscale characterization as well as manufacturing processing. Electrocatalysts, particularly fuel cell catalysts, are dramatically different from heterogeneous catalysts because the surface area in micropores cannot be electrochemically controlled on the same time scale as more transport accessible surfaces. Therefore, electrocatalytic architectures need minimal microporous surface area while maximizing surfaces accessible through mesopores or macropores, and to "pin" the most active, highest performance physicochemical state of the materials even when exposed to thermodynamic forces, which would otherwise drive restructuring, crystallization, or densification of the nanoscale materials. In this presentation, results of engineering nanoscale platinum alloy particles down to 2 ~ 4 nm will be discussed. Based on nature of alloyed base metals, various synthesis technologies have been studied and developed to achieve capabilities of controlling particle size and particle microcomposition, namely, core-shell synthesis, microemulsion technique, thermal decomposition process, surface organometallic chemical method, etc. The results show that by careful engineering the

  17. Fabrication of all diamond scanning probes for nanoscale magnetometry

    OpenAIRE

    Appel Patrick; Neu Elke; Ganzhorn Marc; Barfuss Arne; Batzer Marietta; Gratz Micha; Tschoepe Andreas; Maletinsky Patrick

    2016-01-01

    The electronic spin of the nitrogen vacancy (NV) center in diamond forms an atomically sized, highly sensitive sensor for magnetic fields. To harness the full potential of individual NV centers for sensing with high sensitivity and nanoscale spatial resolution, NV centers have to be incorporated into scanning probe structures enabling controlled scanning in close proximity to the sample surface. Here, we present an optimized procedure to fabricate single-crystal, all-diamond scanning probes s...

  18. Development of simplified rotating plug seal structure

    International Nuclear Information System (INIS)

    Ueta, M.; Ichimiya, M.; Kanaoka, T.; Sekiya, H.; Ueda, S.; Ishibashi, S.

    1991-01-01

    We studied a compact and simplified rotating plug seal structure and conducted experiments for key elements of the concept such us the mechanical seal structure and sodium deposit prevention system. Good characteristics were confirmed for the mechanical seal structure, which utilizes an elastomer seal and thin lathe bearing. Applicability of the density barrier concept was also confirmed as the sodium deposit prevention system. This concept can be applied to actual plants. (author)

  19. Recent technological developments in accelerating structures

    International Nuclear Information System (INIS)

    Yamazaki, Y.

    1992-01-01

    A variety of high-β accelerating structures for both proton and electron accelerators are reviewed from modern points of view. Both standing-and traveling-wave structures are discussed. Beam stability is one of the most important factors which must be taken into account regarding modern accelerators in which the beam intensity is an issue. (Author) 3 figs., 3 tabs., 60 refs

  20. Nanoscale strengthening mechanisms in metallic thin film systems

    Science.gov (United States)

    Schoeppner, Rachel Lynn

    Nano-scale strengthening mechanisms for thin films were investigated for systems governed by two different strengthening techniques: nano-laminate strengthening and oxide dispersion strengthening. Films were tested under elevated temperature conditions to investigate changes in deformation mechanisms at different operating temperatures, and the structural stability. Both systems exhibit remarkable stability after annealing and thus long-term reliability. Nano-scale metallic multilayers with smaller layer thicknesses show a greater relative resistance to decreasing strength at higher temperature testing conditions than those with larger layer thicknesses. This is seen in both Cu/Ni/Nb multilayers as well as a similar tri-component bi-layer system (Cu-Ni/Nb), which removed the coherent interface from the film. Both nanoindentation and micro-pillar compression tests investigated the strain-hardening ability of these two systems to determine what role the coherent interface plays in this mechanism. Tri-layer films showed a higher strain-hardening ability as the layer thickness decreased and a higher strain-hardening exponent than the bi-layer system: verifying the presence of a coherent interface increases the strain-hardening ability of these multilayer systems. Both systems exhibited hardening of the room temperature strength after annealing, suggesting a change in microstructure has occurred, unlike that seen in other multilayer systems. Oxide dispersion strengthened Au films showed a marked increase in hardness and wear resistance with the addition of ZnO particles. The threshold for stress-induced grain-refinement as opposed to grain growth is seen at concentrations of at least 0.5 vol%. These systems exhibited stable microstructures during thermal cycling in films containing at least 1.0%ZnO. Nanoindentation experiments show the drop in hardness following annealing is almost completely attributed to the resulting grain growth. Four-point probe resistivity

  1. Super-resolution fluorescence imaging of membrane nanoscale architectures of hematopoietic stem cell homing and migration molecules

    KAUST Repository

    AbuZineh, Karmen

    2017-12-01

    Recent development of super-resolution (SR) fluorescence microscopy techniques has provided a new tool for direct visualization of subcellular structures and their dynamics in cells. The homing of Hematopoietic stem/progenitor cells (HSPCs) to bone marrow is a multistep process that is initiated by tethering of HSPCs to endothelium and mediated by spatiotemporally organised ligand-receptor interactions of selectins expressed on endothelial cells to their ligands expressed on HSPCs which occurs against the shear stress exerted by blood flow. Although molecules and biological processes involved in this multi-step cellular interaction have been studied extensively, molecular mechanisms of the homing, in particular the nanoscale spatiotemporal behaviour of ligand-receptor interactions and their role in the cellular interaction, remain elusive. Using our new method of microfluidics-based super-resolution fluorescence imaging platform we can now characterize the correlation between both nanoscale ligand-receptor interactions and tethering/rolling of cells under external shear stress. We found that cell rolling on E-selectin caused significant reorganization of the nanoscale clustering behavior of CD44 and CD43, from a patchy clusters of ~ 200 nm in size to an elongated network-like structures where for PSGL-1 the clustering size did not change significantly as it was 85 nm and after cell rolling the PSGL-1 aggregated to one side or even exhibited an increase in the footprint. Furthermore, I have established the use of 3D SR images that indicated that the patchy clusters of CD44 localize to protruding structures of the cell surface. On the other hand, a significant amount of the network-like elongated CD44 clusters observed after the rolling were located in the close proximity to the E-selectin surface. The effect of the nanoscale reorganization of the clusters on the HSPC rolling over selectins is still an open question at this stage. Nevertheless, my results further

  2. Overview of nanoscale NEXAFS performed with soft X-ray microscopes

    Directory of Open Access Journals (Sweden)

    Peter Guttmann

    2015-02-01

    Full Text Available Today, in material science nanoscale structures are becoming more and more important. Not only for the further miniaturization of semiconductor devices like carbon nanotube based transistors, but also for newly developed efficient energy storage devices, gas sensors or catalytic systems nanoscale and functionalized materials have to be analysed. Therefore, analytical tools like near-edge X-ray absorption fine structure (NEXAFS spectroscopy has to be applied on single nanostructures. Scanning transmission X-ray microscopes (STXM as well as full-field transmission X-ray microscopes (TXM allow the required spatial resolution to study individual nanostructures. In the soft X-ray energy range only STXM was used so far for NEXAFS studies. Due to its unique setup, the TXM operated by the Helmholtz-Zentrum Berlin (HZB at the electron storage ring BESSY II is the first one in the soft X-ray range which can be used for NEXAFS spectroscopy studies which will be shown in this review. Here we will give an overview of the different microscopes used for NEXAFS studies and describe their advantages and disadvantages for different samples.

  3. Overview of nanoscale NEXAFS performed with soft X-ray microscopes.

    Science.gov (United States)

    Guttmann, Peter; Bittencourt, Carla

    2015-01-01

    Today, in material science nanoscale structures are becoming more and more important. Not only for the further miniaturization of semiconductor devices like carbon nanotube based transistors, but also for newly developed efficient energy storage devices, gas sensors or catalytic systems nanoscale and functionalized materials have to be analysed. Therefore, analytical tools like near-edge X-ray absorption fine structure (NEXAFS) spectroscopy has to be applied on single nanostructures. Scanning transmission X-ray microscopes (STXM) as well as full-field transmission X-ray microscopes (TXM) allow the required spatial resolution to study individual nanostructures. In the soft X-ray energy range only STXM was used so far for NEXAFS studies. Due to its unique setup, the TXM operated by the Helmholtz-Zentrum Berlin (HZB) at the electron storage ring BESSY II is the first one in the soft X-ray range which can be used for NEXAFS spectroscopy studies which will be shown in this review. Here we will give an overview of the different microscopes used for NEXAFS studies and describe their advantages and disadvantages for different samples.

  4. Electrokinetic aspects of water filtration by AlOOH-coated siliceous particles with nanoscale roughness

    Directory of Open Access Journals (Sweden)

    Leonid A. Kaledin

    2017-03-01

    Full Text Available The vast majority of analytical and numerical models developed to explain pressure-driven electrokinetic phenomena assume that the local electrical double layer field over heterogenious surfaces is independent of the flow field and described by the Poison-Boltzman equation. However, for pressure-driven flow over a surface with heterogeneous patches with combined microscale and nanoscale structures the local electrical double layer fields are different above the patch and in the region between the patches. The nonuniform surface charge produces distortions in the equilibrium electrostatic field. The characteristic symptom of field distortion is the generation of flow velocities in all three coordinate directions, including a circulation pattern perpendicular to the main flow axis therefore severely distorting the Poisson-Boltzmann double layer. The result is an exceptionally high microbes and ions removal efficiencies from aqueous suspension by the alumina’s surfaces with combined microscale and nanoscale structures that strongly suggests existence of a coupling effect of the local electrical double layer (EDL field with the local flow field.

  5. Nanoscale cryptography: opportunities and challenges.

    Science.gov (United States)

    Masoumi, Massoud; Shi, Weidong; Xu, Lei

    2015-01-01

    While most of the electronics industry is dependent on the ever-decreasing size of lithographic transistors, this scaling cannot continue indefinitely. To improve the performance of the integrated circuits, new emerging and paradigms are needed. In recent years, nanoelectronics has become one of the most important and exciting forefront in science and engineering. It shows a great promise for providing us in the near future with many breakthroughs that change the direction of technological advances in a wide range of applications. In this paper, we discuss the contribution that nanotechnology may offer to the evolution of cryptographic hardware and embedded systems and demonstrate how nanoscale devices can be used for constructing security primitives. Using a custom set of design automation tools, it is demonstrated that relative to a conventional 45-nm CMOS system, performance gains can be obtained up to two orders of magnitude reduction in area and up to 50 % improvement in speed.

  6. Nanoscale Mixing of Soft Solids

    International Nuclear Information System (INIS)

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

    2011-01-01

    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 30 H 62 ) adopt a body-centered cubic (bcc) lattice, with glassy PS cores. Utilizing small-angle neutron scattering (SANS) and isotopic labeling ( 1 H and 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.

  7. Low-cost solar array structure development

    Science.gov (United States)

    Wilson, A. H.

    1981-06-01

    Early studies of flat-plate arrays have projected costs on the order of $50/square meter for installed array support structures. This report describes an optimized low-cost frame-truss structure that is estimated to cost below $25/square meter, including all markups, shipping an installation. The structure utilizes a planar frame made of members formed from light-gauge galvanized steel sheet and is supposed in the field by treated-wood trusses that are partially buried in trenches. The buried trusses use the overburden soil to carry uplift wind loads and thus to obviate reinforced-concrete foundations. Details of the concept, including design rationale, fabrication and assembly experience, structural testing and fabrication drawings are included.

  8. Development of cold source moderator structure

    International Nuclear Information System (INIS)

    Aso, Tomokaze; Ishikura, Syuichi; Terada, Atsuhiko; Teshigawara, Makoto; Watanabe, Noboru; HIno, Ryutaro

    1999-01-01

    The cold and thermal neutrons generated at the target (which works as a spallation neutron source under a 5MW proton beam condition) is filtered with cold source moderators using supercritical hydrogen. Preliminary structural analysis was carried out to clarify technical problems on the concept of the thin-walled structure for the cold source moderator. Structural analytical results showed that the maximum stress of 1 12MPa occurred on the moderator surface, which exceeded the allowable design stresses of ordinary aluminum alloys. Flow patterns measured by water flow experiments agreed well with hydraulic analytical results, which showed that an impinging jet flow from an inner pipe of the moderator caused a recirculation flow on a large scale. Based on analytical and experimental results, new moderator structures with minute frames, blowing flow holes etc. were proposed to keep its strength and to suppress the recirculation flow. (author)

  9. Wakefield monitor development for CLIC accelerating structure

    CERN Document Server

    Peauger, F; Girardot, P; Andersson, A; Riddone, G; Samoshkin, A; Solodko, A; Zennaro, R; Ruber, R

    2010-01-01

    Abstract To achieve high luminosity in CLIC, the accelerating structures must be aligned to an accuracy of 5 μm with respect to the beam trajectory. Position detectors called Wakefield Monitors (WFM) are integrated to the structure for a beam based alignment. This paper describes the requirements of such monitors. Detailed RF design and electromagnetic simulations of the WFM itself are presented. In particular, time domain computations are performed and an evaluation of the resolution is done for two higher order modes at 18 and 24 GHz. The mechanical design of a prototype accelerating structure with WFM is also presented as well as the fabrication status of three complete structures. The objective is to implement two of them in CTF3 at CERN for a feasibility demonstration with beam and high power rf.

  10. Nanoscale and submicron fatigue crack growth in nickel microbeams

    International Nuclear Information System (INIS)

    Yang, Y.; Yao, N.; Imasogie, B.; Soboyejo, W.O.

    2007-01-01

    This paper presents a novel edge-notched microbeam technique for the study of short fatigue crack growth. The technique is used to study submicron and nanoscale fatigue in LIGA Ni thin films with columnar microstructures. The edge-notched microbeams were fabricated within LIGA Ni thin films, using focused ion beam (FIB) techniques. The microbeams were then cyclically deformed to failure at a stress ratio of 0.1. Different slip-band structures were observed below the nanoscale notches. Cyclic deformation resulted in the formation of primary slip bands below the notch. Subsequent crack growth then occurred by the unzipping of fatigue cracks along intersecting slip bands. The effects of the primary slip bands were idealized using dislocation-based models. These were used to estimate the intrinsic fatigue threshold and the fatigue endurance limit. The estimates from the model are shown to be consistent with experimental data from prior stress-life experiments and current/prior fatigue threshold estimates

  11. 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.

  12. Brillouin gain enhancement in nano-scale photonic waveguide

    Science.gov (United States)

    Nouri Jouybari, Soodabeh

    2018-05-01

    The enhancement of stimulated Brillouin scattering in nano-scale waveguides has a great contribution in the improvement of the photonic devices technology. The key factors in Brillouin gain are the electrostriction force and radiation pressure generated by optical waves in the waveguide. In this article, we have proposed a new scheme of nano-scale waveguide in which the Brillouin gain is considerably improved compared to the previously-reported schemes. The role of radiation pressure in the Brillouin gain was much higher than the role of the electrostriction force. The Brillouin gain strongly depends on the structural parameters of the waveguide and the maximum value of 12127 W-1 m-1 is obtained for the Brillouin gain.

  13. Nanoscale semiconducting silicon as a nutritional food additive

    International Nuclear Information System (INIS)

    Canham, L T

    2007-01-01

    Very high surface area silicon powders can be realized by high energy milling or electrochemical etching techniques. Such nanoscale silicon structures, whilst biodegradable in the human gastrointestinal tract, are shown to be remarkably stable in most foodstuffs and beverages. The potential for using silicon to improve the shelf life and bioavailability of specific nutrients in functional foods is highlighted. Published drug delivery data implies that the nanoentrapment of hydrophobic nutrients will significantly improve their dissolution kinetics, through a combined effect of nanostructuring and solid state modification. Nutrients loaded to date include vitamins, fish oils, lycopene and coenzyme Q10. In addition, there is growing published evidence that optimized release of orthosilicic acid, the biodegradation product of semiconducting silicon in the gut, offers beneficial effects with regard bone health. The utility of nanoscale silicon in the nutritional field shows early promise and is worthy of much further study

  14. Nanoscale semiconducting silicon as a nutritional food additive

    Energy Technology Data Exchange (ETDEWEB)

    Canham, L T [pSiNutria Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire WR14 3SZ (United Kingdom)

    2007-05-09

    Very high surface area silicon powders can be realized by high energy milling or electrochemical etching techniques. Such nanoscale silicon structures, whilst biodegradable in the human gastrointestinal tract, are shown to be remarkably stable in most foodstuffs and beverages. The potential for using silicon to improve the shelf life and bioavailability of specific nutrients in functional foods is highlighted. Published drug delivery data implies that the nanoentrapment of hydrophobic nutrients will significantly improve their dissolution kinetics, through a combined effect of nanostructuring and solid state modification. Nutrients loaded to date include vitamins, fish oils, lycopene and coenzyme Q10. In addition, there is growing published evidence that optimized release of orthosilicic acid, the biodegradation product of semiconducting silicon in the gut, offers beneficial effects with regard bone health. The utility of nanoscale silicon in the nutritional field shows early promise and is worthy of much further study.

  15. Nanoscale Rheology and Anisotropic Diffusion Using Single Gold Nanorod Probes

    Science.gov (United States)

    Molaei, Mehdi; Atefi, Ehsan; Crocker, John C.

    2018-03-01

    The complex rotational and translational Brownian motion of anisotropic particles depends on their shape and the viscoelasticity of their surroundings. Because of their strong optical scattering and chemical versatility, gold nanorods would seem to provide the ultimate probes of rheology at the nanoscale, but the suitably accurate orientational tracking required to compute rheology has not been demonstrated. Here we image single gold nanorods with a laser-illuminated dark-field microscope and use optical polarization to determine their three-dimensional orientation to better than one degree. We convert the rotational diffusion of single nanorods in viscoelastic polyethylene glycol solutions to rheology and obtain excellent agreement with bulk measurements. Extensions of earlier models of anisotropic translational diffusion to three dimensions and viscoelastic fluids give excellent agreement with the observed motion of single nanorods. We find that nanorod tracking provides a uniquely capable approach to microrheology and provides a powerful tool for probing nanoscale dynamics and structure in a range of soft materials.

  16. Heat transfer across the interface between nanoscale solids and gas.

    Science.gov (United States)

    Cheng, Chun; Fan, Wen; Cao, Jinbo; Ryu, Sang-Gil; Ji, Jie; Grigoropoulos, Costas P; Wu, Junqiao

    2011-12-27

    When solid materials and devices scale down in size, heat transfer from the active region to the gas environment becomes increasingly significant. We show that the heat transfer coefficient across the solid-gas interface behaves very differently when the size of the solid is reduced to the nanoscale, such as that of a single nanowire. Unlike for macroscopic solids, the coefficient is strongly pressure dependent above ∼10 Torr, and at lower pressures it is much higher than predictions of the kinetic gas theory. The heat transfer coefficient was measured between a single, free-standing VO(2) nanowire and surrounding air using laser thermography, where the temperature distribution along the VO(2) nanowire was determined by imaging its domain structure of metal-insulator phase transition. The one-dimensional domain structure along the nanowire results from the balance between heat generation by the focused laser and heat dissipation to the substrate as well as to the surrounding gas, and thus serves as a nanoscale power-meter and thermometer. We quantified the heat loss rate across the nanowire-air interface, and found that it dominates over all other heat dissipation channels for small-diameter nanowires near ambient pressure. As the heat transfer across the solid-gas interface is nearly independent of the chemical identity of the solid, the results reveal a general scaling relationship for gaseous heat dissipation from nanostructures of all solid materials, which is applicable to nanoscale electronic and thermal devices exposed to gaseous environments.

  17. The nanoscale organization of the B lymphocyte membrane☆

    Science.gov (United States)

    Maity, Palash Chandra; Yang, Jianying; Klaesener, Kathrin; Reth, Michael

    2015-01-01

    The fluid mosaic model of Singer and Nicolson correctly predicted that the plasma membrane (PM) forms a lipid bi-layer containing many integral trans-membrane proteins. This model also suggested that most of these proteins were randomly dispersed and freely diffusing moieties. Initially, this view of a dynamic and rather unorganized membrane was supported by early observations of the cell surfaces using the light microscope. However, recent studies on the PM below the diffraction limit of visible light (~ 250 nm) revealed that, at nanoscale dimensions, membranes are highly organized and compartmentalized structures. Lymphocytes are particularly useful to study this nanoscale membrane organization because they grow as single cells and are not permanently engaged in cell:cell contacts within a tissue that can influence membrane organization. In this review, we describe the methods that can be used to better study the protein:protein interaction and nanoscale organization of lymphocyte membrane proteins, with a focus on the B cell antigen receptor (BCR). Furthermore, we discuss the factors that may generate and maintain these membrane structures. PMID:25450974

  18. Nanoscale form dictates mesoscale function in plasmonic DNA–nanoparticle superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Michael B.; Ku, Jessie C.; Vaccarezza, Victoria M.; Schatz, George C.; Mirkin , Chad A. (NWU)

    2016-06-15

    The nanoscale manipulation of matter allows properties to be created in a material that would be difficult or even impossible to achieve in the bulk state. Progress towards such functional nanoscale architectures requires the development of methods to precisely locate nanoscale objects in three dimensions and for the formation of rigorous structure–function relationships across multiple size regimes (beginning from the nanoscale). Here, we use DNA as a programmable ligand to show that two- and three-dimensional mesoscale superlattice crystals with precisely engineered optical properties can be assembled from the bottom up. The superlattices can transition from exhibiting the properties of the constituent plasmonic nanoparticles to adopting the photonic properties defined by the mesoscale crystal (here a rhombic dodecahedron) by controlling the spacing between the gold nanoparticle building blocks. Furthermore, we develop a generally applicable theoretical framework that illustrates how crystal habit can be a design consideration for controlling far-field extinction and light confinement in plasmonic metamaterial superlattices.

  19. Nanoscale dislocation shear loops at static equilibrium and finite temperature

    Science.gov (United States)

    Dang, Khanh; Capolungo, Laurent; Spearot, Douglas E.

    2017-12-01

    Atomistic simulations are used to determine the resolved shear stress necessary for equilibrium and the resulting geometry of nanoscale dislocation shear loops in Al. Dislocation loops with different sizes and shapes are created via superposition of elemental triangular dislocation displacement fields in the presence of an externally imposed shear stress. First, a bisection algorithm is developed to determine systematically the resolved shear stress necessary for equilibrium at 0 K. This approach allows for the identification of dislocation core structure and a correlation between dislocation loop size, shape and the computed shear stress for equilibrium. It is found, in agreement with predictions made by Scattergood and Bacon, that the equilibrium shape of a dislocation loop becomes more circular with increasing loop size. Second, the bisection algorithm is extended to study the influence of temperature on the resolved shear stress necessary for stability. An approach is presented to compute the effective lattice friction stress, including temperature dependence, for dislocation loops in Al. The temperature dependence of the effective lattice friction stress can be reliably computed for dislocation loops larger than 16.2 nm. However, for dislocation loops smaller than this threshold, the effective lattice friction stress shows a dislocation loop size dependence caused by significant overlap of the stress fields on the interior of the dislocation loops. Combined, static and finite temperature atomistic simulations provide essential data to parameterize discrete dislocation dynamics simulations.

  20. 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.

  1. Nanoscale devices based on plasmonic coaxial waveguide resonators

    Science.gov (United States)

    Mahigir, A.; Dastmalchi, P.; Shin, W.; Fan, S.; Veronis, G.

    2015-02-01

    Waveguide-resonator systems are particularly useful for the development of several integrated photonic devices, such as tunable filters, optical switches, channel drop filters, reflectors, and impedance matching elements. In this paper, we introduce nanoscale devices based on plasmonic coaxial waveguide resonators. In particular, we investigate threedimensional nanostructures consisting of plasmonic coaxial stub resonators side-coupled to a plasmonic coaxial waveguide. We use coaxial waveguides with square cross sections, which can be fabricated using lithography-based techniques. The waveguides are placed on top of a silicon substrate, and the space between inner and outer coaxial metals is filled with silica. We use silver as the metal. We investigate structures consisting of a single plasmonic coaxial resonator, which is terminated either in a short or an open circuit, side-coupled to a coaxial waveguide. We show that the incident waveguide mode is almost completely reflected on resonance, while far from the resonance the waveguide mode is almost completely transmitted. We also show that the properties of the waveguide systems can be accurately described using a single-mode scattering matrix theory. The transmission and reflection coefficients at waveguide junctions are either calculated using the concept of the characteristic impedance or are directly numerically extracted using full-wave three-dimensional finite-difference frequency-domain simulations.

  2. Nanoscale control of energy and matter in plasma-surface interactions: towards energy-efficient nanotech

    Science.gov (United States)

    Ostrikov, Kostya

    2010-11-01

    This presentation focuses on the plasma issues related to the solution of the grand challenge of directing energy and matter at nanoscales. This ability is critical for the renewable energy and energy-efficient technologies for sustainable future development. It will be discussed how to use environmentally and human health benign non-equilibrium plasma-solid systems and control the elementary processes of plasma-surface interactions to direct the fluxes of energy and matter at multiple temporal and spatial scales. In turn, this makes it possible to achieve the deterministic synthesis of self- organised arrays of metastable nanostructures in the size range beyond the reach of the present-day nanofabrication. Such structures have tantalising prospects to enhance performance of nanomaterials in virtually any area of human activity yet remain almost inaccessible because the Nature's energy minimisation rules allow only a small number of stable equilibrium states. By using precisely controlled and kinetically fast nanoscale transfer of energy and matter under non-equilibrium conditions and harnessing numerous plasma- specific controls of species creation, delivery to the surface, nucleation and large-scale self-organisation of nuclei and nanostructures, the arrays of metastable nanostructures can be created, arranged, stabilised, and further processed to meet the specific requirements of the envisaged applications. These approaches will eventually lead to faster, unprecedentedly- clean, human-health-friendly, and energy-efficient nanoscale synthesis and processing technologies for the next-generation renewable energy and light sources, biomedical devices, information and communication systems, as well as advanced functional materials for applications ranging from basic food, water, health and clean environment needs to national security and space missions.

  3. Osteogenic response of human mesenchymal stem cells to well-defined nanoscale topography in vitro

    Directory of Open Access Journals (Sweden)

    de Peppo GM

    2014-05-01

    Full Text Available Giuseppe Maria de Peppo,1–3 Hossein Agheli,2,3 Camilla Karlsson,2,3 Karin Ekström,2,3 Helena Brisby,3,4 Maria Lennerås,2,3 Stefan Gustafsson,3,5 Peter Sjövall,3,5,6 Anna Johansson,2,3 Eva Olsson,3,5 Jukka Lausmaa,3,6 Peter Thomsen,2,3 Sarunas Petronis3,6 1The New York Stem Cell Foundation Research Institute, New York, NY, USA; 2Department of Biomaterials, Sahlgrenska Academy, University of Gothenburg, 3BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, 4Department of Orthopaedics, Sahlgrenska Academy, University of Gothenburg, 5Applied Physics, Chalmers University of Technology, Göteborg, Sweden; 6Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Borås, Sweden Background: Patterning medical devices at the nanoscale level enables the manipulation of cell behavior and tissue regeneration, with topographic features recognized as playing a significant role in the osseointegration of implantable devices. Methods: In this study, we assessed the ability of titanium-coated hemisphere-like topographic nanostructures of different sizes (approximately 50, 100, and 200 nm to influence the morphology, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs. Results: We found that the proliferation and osteogenic differentiation of hMSCs was influenced by the size of the underlying structures, suggesting that size variations in topographic features at the nanoscale level, independently of chemistry, can be exploited to control hMSC behavior in a size-dependent fashion. Conclusion: Our studies demonstrate that colloidal lithography, in combination with coating technologies, can be exploited to investigate the cell response to well defined nanoscale topography and to develop next-generation surfaces that guide tissue regeneration and promote implant integration. Keywords: colloidal lithography, nanotopography, human mesenchymal stem cells, cell proliferation, osteogenic

  4. Nanoscale Correlated Disorder in Out-of-Equilibrium Myelin Ultrastructure.

    Science.gov (United States)

    Campi, Gaetano; Di Gioacchino, Michael; Poccia, Nicola; Ricci, Alessandro; Burghammer, Manfred; Ciasca, Gabriele; Bianconi, Antonio

    2018-01-23

    Ultrastructural fluctuations at nanoscale are fundamental to assess properties and functionalities of advanced out-of-equilibrium materials. We have taken myelin as a model of supramolecular assembly in out-of-equilibrium living matter. Myelin sheath is a simple stable multilamellar structure of high relevance and impact in biomedicine. Although it is known that myelin has a quasi-crystalline ultrastructure, there is no information on its fluctuations at nanoscale in different states due to limitations of the available standard techniques. To overcome these limitations, we have used scanning micro X-ray diffraction, which is a unique non-invasive probe of both reciprocal and real space to visualize statistical fluctuations of myelin order of the sciatic nerve of Xenopus laevis. The results show that the ultrastructure period of the myelin is stabilized by large anticorrelated fluctuations at nanoscale, between hydrophobic and hydrophilic layers. The ratio between the total thickness of hydrophilic and hydrophobic layers defines the conformational parameter, which describes the different states of myelin. Our key result is that myelin in its out-of-equilibrium functional state fluctuates point-to-point between different conformations showing a correlated disorder described by a Levy distribution. As the system approaches the thermodynamic equilibrium in an aged state, the disorder loses its correlation degree and the structural fluctuation distribution changes to Gaussian. In a denatured state at low pH, it changes to a completely disordered stage. Our results aim to clarify the degradation mechanism in biological systems by associating these states with ultrastructural dynamic fluctuations at nanoscale.

  5. Development in structural systems reliability theory

    International Nuclear Information System (INIS)

    Murotsu, Y.

    1986-01-01

    This paper is concerned with two topics on structural systems reliability theory. One covers automatic generation of failure mode equations, identifications of stochastically dominant failure modes, and reliability assessment of redundant structures. Reduced stiffness matrixes and equivalent nodal forces representing the failed elements are introduced for expressing the safety of the elements, using a matrix method. Dominant failure modes are systematically selected by a branch-and-bound technique and heuristic operations. The other discusses the various optimum design problems based on reliability concept. Those problems are interpreted through a solution to a multi-objective optimization problem. (orig.)

  6. Development in structural systems reliability theory

    Energy Technology Data Exchange (ETDEWEB)

    Murotsu, Y

    1986-07-01

    This paper is concerned with two topics on structural systems reliability theory. One covers automatic generation of failure mode equations, identifications of stochastically dominant failure modes, and reliability assessment of redundant structures. Reduced stiffness matrixes and equivalent nodal forces representing the failed elements are introduced for expressing the safety of the elements, using a matrix method. Dominant failure modes are systematically selected by a branch-and-bound technique and heuristic operations. The other discusses the various optimum design problems based on reliability concept. Those problems are interpreted through a solution to a multi-objective optimization problem.

  7. Economic development and industrial structure - an overview

    Energy Technology Data Exchange (ETDEWEB)

    Nordaas, Hildegunn Kyvik

    1997-09-01

    The essay offers a selective review of central issues related to economic growth. The interrelationship between technological progress, capital accumulation, specialisation and industrial structure is emphasised. It is concluded that, first, there is little evidence that industrial structure plays an independent role in growth. Second, economists have been more successful in explaining the consequence of technological progress than the determinants of technological progress. However, even the consequences are not well understood and there is still a long way to go before general and well-documented policy implications can be drawn. (Author)

  8. The use of nanoscale fluorescence microscopic to decipher cell wall modifications during fungal penetration

    Directory of Open Access Journals (Sweden)

    Dorothea eEllinger

    2014-06-01

    Full Text Available Plant diseases are one of the most studied subjects in the field of plant science due to their impact on crop yield and food security. Our increased understanding of plant–pathogen interactions was mainly driven by the development of new techniques that facilitated analyses on a subcellular and molecular level. The development of labeling technologies, which allowed the visualization and localization of cellular structures and proteins in live cell imaging, promoted the use of fluorescence and laser-scanning microscopy in the field of plant–pathogen interactions. Recent advances in new microscopic technologies opened their application in plant science and in the investigation of plant diseases. In this regard, in planta Förster/Fluorescence resonance energy transfer has demonstrated to facilitate the measurement of protein-protein interactions within the living tissue, supporting the analysis of regulatory pathways involved in plant immunity and putative host-pathogen interactions on a nanoscale level. Localization microscopy, an emerging, non-invasive microscopic technology, will allow investigations with a nanoscale resolution leading to new possibilities in the understanding of molecular processes.

  9. Role of Lithology and Rock Structure in Drainage Development in ...

    African Journals Online (AJOL)

    Lithology and Rock structure play a vital role in the development of Drainage Network in any drainage basin. The drainage patterns upon land surface develop as directed by the underlying lithology and rock structure. In fact, lithology and rock structure together shape the basin and are decisive parameters of nature and ...

  10. EDITORIAL: Quantum science and technology at the nanoscale Quantum science and technology at the nanoscale

    Science.gov (United States)

    Demming, Anna

    2010-07-01

    The development of quantum theory was an archetypal scientific revolution in early twentieth-century physics. In many ways, the probabilities and uncertainties that replaced the ubiquitous application of classical mechanics may have seemed a violent assault on logic and reason. 'Something unknown is doing we don't know what-that is what our theory amounts to,' Sir Arthur Eddington famously remarked, adding, 'It does not sound a particularly illuminating theory. I have read something like it elsewhere: the slithy toves, did gyre and gimble in the wabe' [1]. Today, quantum mechanics no longer seems a dark art best confined to the boundaries of physics and philosophy. Scanning probe micrographs have captured actual images of quantum-mechanical interference patterns [2], and familiarity has made the claims of quantum theory more palatable. An understanding of quantum effects is essential for nanoscale science and technology research. This special issue on quantum science and technology at the nanoscale collates some of the latest research that is extending the boundaries of our knowledge and understanding in the field. Quantum phenomena have become particularly significant in attempts to further reduce the size of electronic devices, the trend widely referred to as Moore's law. In this issue, researchers in Switzerland report results from transport studies on graphene. The researchers investigate the conductance variance in systems with superconducting contacts [3]. Also in this issue, researchers in Germany calculate the effects of spin-orbit coupling in a molecular dimer and predict nonlinear transport. They also explain how ferromagnetic electrodes can be used to probe these interactions [4]. Our understanding of spin and the ability to manipulate it has advanced greatly since the notion of spin was first proposed. However, it remains the case that little is known about local coherent fluctuations of spin polarizations, the scale on which they occur, how they are

  11. Electricity supply of Switzerland. Development and structure

    International Nuclear Information System (INIS)

    Mutzner, J.

    1995-01-01

    An overview of the history of the Swiss power supply since the founding of the Swiss Electricity Works Association in the year 1985 is provided. Power supply, requirements, linkage and exchange with other countries are dealt with. Further themes are the organizational structures, tariffs, power supply and energy policies, as well as national and international connections. 87 figs., 40 refs

  12. Tube Formation in Nanoscale Materials

    Directory of Open Access Journals (Sweden)

    Yan Chenglin

    2008-01-01

    Full Text Available Abstract The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gas–solid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquid–solid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities.

  13. A constitutive model of soft tissue: From nanoscale collagen to tissue continuum

    KAUST Repository

    Tang, Huang

    2009-04-08

    Soft collagenous tissue features many hierarchies of structure, starting from tropocollagen molecules that form fibrils, and proceeding to a bundle of fibrils that form fibers. Here we report the development of an atomistically informed continuum model of collagenous tissue. Results from full atomistic and molecular modeling are linked with a continuum theory of a fiber-reinforced composite, handshaking the fibril scale to the fiber and continuum scale in a hierarchical multi-scale simulation approach. Our model enables us to study the continuum-level response of the tissue as a function of cross-link density, making a link between nanoscale collagen features and material properties at larger tissue scales. The results illustrate a strong dependence of the continuum response as a function of nanoscopic structural features, providing evidence for the notion that the molecular basis for protein materials is important in defining their larger-scale mechanical properties. © 2009 Biomedical Engineering Society.

  14. Patterning high explosives at the nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Nafday, Omkar A.; Pitchimani, Rajasekar; Weeks, Brandon L. [Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409 (United States); Haaheim, Jason [NanoInk Inc., 8025 Lamon Ave., Skokie, IL 60077 (United States)

    2006-10-15

    For the first time, we have shown that spin coating and Dip pen nanolithography (DPN trademark) are simple methods of preparing energetic materials such as PETN and HMX on the nanoscale, requiring no heating of the energetic material. Nanoscale patterning has been demonstrated by the DPN method while continuous thin films were produced using the spin coating method. Results are presented for preparing continuous PETN thin films of nanometer thickness by the spin coating method and for controlling the architecture of arbitrary nanoscale patterns of PETN and HMX by the DPN method. These methods are simple for patterning energetic materials and can be extended beyond PETN and HMX, opening the door for fundamental studies at the nanoscale. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  15. Quantum Transport Simulations of Nanoscale Materials

    KAUST Repository

    Obodo, Tobechukwu Joshua

    2016-01-01

    -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

  16. Nanoscale drug delivery for targeted chemotherapy.

    Science.gov (United States)

    Xin, Yong; Huang, Qian; Tang, Jian-Qin; Hou, Xiao-Yang; Zhang, Pei; Zhang, Long Zhen; Jiang, Guan

    2016-08-28

    Despite significant improvements in diagnostic methods and innovations in therapies for specific cancers, effective treatments for neoplastic diseases still represent major challenges. Nanotechnology as an emerging technology has been widely used in many fields and also provides a new opportunity for the targeted delivery of cancer drugs. Nanoscale delivery of chemotherapy drugs to the tumor site is highly desirable. Recent studies have shown that nanoscale drug delivery systems not only have the ability to destroy cancer cells but may also be carriers for chemotherapy drugs. Some studies have demonstrated that delivery of chemotherapy via nanoscale carriers has greater therapeutic benefit than either treatment modality alone. In this review, novel approaches to nanoscale delivery of chemotherapy are described and recent progress in this field is discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. In situ characterization of nanoscale catalysts during anodic redox processes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Renu [National Institute of Standards and Technology; Crozier, Peter [Arizona State University; Adams, James [Arizona State University

    2013-09-19

    Controlling the structure and composition of the anode is critical to achieving high efficiency and good long-term performance. In addition to being a mixed electronic and ionic conductor, the ideal anode material should act as an efficient catalyst for oxidizing hydrogen, carbon monoxide and dry hydrocarbons without de-activating through either sintering or coking. It is also important to develop novel anode materials that can operate at lower temperatures to reduce costs and minimized materials failure associated with high temperature cycling. We proposed to synthesize and characterize novel anode cermets materials based on ceria doped with Pr and/or Gd together with either a Ni or Cu metallic components. Ceria is a good oxidation catalyst and is an ionic conductor at room temperature. Doping it with trivalent rare earths such as Pr or Gd retards sintering and makes it a mixed ion conductor (ionic and electronic). We have developed a fundamental scientific understanding of the behavior of the cermet material under reaction conditions by following the catalytic oxidation process at the atomic scale using a powerful Environmental Scanning Transmission Electron Microscope (ESTEM). The ESTEM allowed in situ monitoring of structural, chemical and morphological changes occurring at the cermet under conditions approximating that of typical fuel-cell operation. Density functional calculations were employed to determine the underlying mechanisms and reaction pathways during anode oxidation reactions. The dynamic behavior of nanoscale catalytic oxidation of hydrogen and methane were used to determine: ? Fundamental processes during anodic reactions in hydrogen and carbonaceous atmospheres ? Interfacial effects between metal particles and doped ceria ? Kinetics of redox reaction in the anode material

  18. Development of structural health monitoring techniques using dynamics testing

    Energy Technology Data Exchange (ETDEWEB)

    James, G.H. III [Sandia National Labs., Albuquerque, NM (United States). Experimental Structural Dynamics Dept.

    1996-03-01

    Today`s society depends upon many structures (such as aircraft, bridges, wind turbines, offshore platforms, buildings, and nuclear weapons) which are nearing the end of their design lifetime. Since these structures cannot be economically replaced, techniques for structural health monitoring must be developed and implemented. Modal and structural dynamics measurements hold promise for the global non-destructive inspection of a variety of structures since surface measurements of a vibrating structure can provide information about the health of the internal members without costly (or impossible) dismantling of the structure. In order to develop structural health monitoring for application to operational structures, developments in four areas have been undertaken within this project: operational evaluation, diagnostic measurements, information condensation, and damage identification. The developments in each of these four aspects of structural health monitoring have been exercised on a broad range of experimental data. This experimental data has been extracted from structures from several application areas which include aging aircraft, wind energy, aging bridges, offshore structures, structural supports, and mechanical parts. As a result of these advances, Sandia National Laboratories is in a position to perform further advanced development, operational implementation, and technical consulting for a broad class of the nation`s aging infrastructure problems.

  19. Fast heat flux modulation at the nanoscale

    OpenAIRE

    van Zwol, P. J.; Joulain, K.; Abdallah, P. Ben; Greffet, J. J.; Chevrier, J.

    2011-01-01

    We introduce a new concept for electrically controlled heat flux modulation. A flux contrast larger than 10 dB is expected with switching time on the order of tens of nanoseconds. Heat flux modulation is based on the interplay between radiative heat transfer at the nanoscale and phase change materials. Such large contrasts are not obtainable in solids, or in far field. As such this opens up new horizons for temperature modulation and actuation at the nanoscale.

  20. THE ESSENCE OF STRATEGY DEVELOPMENT COMPANY IN THE INTEGRATED STRUCTURE

    Directory of Open Access Journals (Sweden)

    A. I. Khorev

    2014-01-01

    Full Text Available Summary. In the beginning of the article is defined a rational sequence of the consideration of the nature of the strategy of a company development, included into an integrated structure. Further the article describes the following items separately: "a strategy", "a development of a company", and "an integrational structure", applying them to companies included to the integrated structure; separating them from a strategy of development of an autonomous company. The article defines functions which such strategy must define, taking into consideration the nature of the strategy of the company development, included into an integrated structure. Next, the article defines six steps which describe a sequence of development of the strategy of the company development, included into an integrated structure. The analysis which is defined in the article allows determining a complete definition of essence of the strategy of the company development, included into an integrated structure. The article also defines a place of the strategy of development into the hierarchical structure of the strategies. The strategy of the company development, included into an integrated structure (as well as the strategy of development of an autonomous company -- is a competition strategy, and it separates "strategy of leadership for costs", “differentiation strategy”, and “strategy of focusing for costs”. Also authors are analyzed the strategy of the cost optimization. According to the complex definition of the strategy, and the strategy's place inside the hierarchical structure, the article defines functions which corporate, competitive, and functional strategies execute during the management of companies inside an integrational structure. The article presents characteristics of applied strategic decisions at different levels of all three types of strategies. The article's researches allow companies included to the integrated structure define their place inside the

  1. Nanoscale strontium titanate photocatalysts for overall water splitting.

    Science.gov (United States)

    Townsend, Troy K; Browning, Nigel D; Osterloh, Frank E

    2012-08-28

    SrTiO(3) (STO) is a large band gap (3.2 eV) semiconductor that catalyzes the overall water splitting reaction under UV light irradiation in the presence of a NiO cocatalyst. As we show here, the reactivity persists in nanoscale particles of the material, although the process is less effective at the nanoscale. To reach these conclusions, Bulk STO, 30 ± 5 nm STO, and 6.5 ± 1 nm STO were synthesized by three different methods, their crystal structures verified with XRD and their morphology observed with HRTEM before and after NiO deposition. In connection with NiO, all samples split water into stoichiometric mixtures of H(2) and O(2), but the activity is decreasing from 28 μmol H(2) g(-1) h(-1) (bulk STO), to 19.4 μmol H(2) g(-1) h(-1) (30 nm STO), and 3.0 μmol H(2) g(-1) h(-1) (6.5 nm STO). The reasons for this decrease are an increase of the water oxidation overpotential for the smaller particles and reduced light absorption due to a quantum size effect. Overall, these findings establish the first nanoscale titanate photocatalyst for overall water splitting.

  2. Extremely flexible nanoscale ultrathin body silicon integrated circuits on plastic.

    Science.gov (United States)

    Shahrjerdi, Davood; Bedell, Stephen W

    2013-01-09

    In recent years, flexible devices based on nanoscale materials and structures have begun to emerge, exploiting semiconductor nanowires, graphene, and carbon nanotubes. This is primarily to circumvent the existing shortcomings of the conventional flexible electronics based on organic and amorphous semiconductors. The aim of this new class of flexible nanoelectronics is to attain high-performance devices with increased packing density. However, highly integrated flexible circuits with nanoscale transistors have not yet been demonstrated. Here, we show nanoscale flexible circuits on 60 Å thick silicon, including functional ring oscillators and memory cells. The 100-stage ring oscillators exhibit the stage delay of ~16 ps at a power supply voltage of 0.9 V, the best reported for any flexible circuits to date. The mechanical flexibility is achieved by employing the controlled spalling technology, enabling the large-area transfer of the ultrathin body silicon devices to a plastic substrate at room temperature. These results provide a simple and cost-effective pathway to enable ultralight flexible nanoelectronics with unprecedented level of system complexity based on mainstream silicon technology.

  3. Personalized Nanomedicine: A Revolution at the Nanoscale

    Directory of Open Access Journals (Sweden)

    Cristina Fornaguera

    2017-10-01

    Full Text Available Nanomedicine is an interdisciplinary research field that results from the application of nanotechnology to medicine and has the potential to significantly improve some current treatments. Specifically, in the field of personalized medicine, it is expected to have a great impact in the near future due to its multiple advantages, namely its versatility to adapt a drug to a cohort of patients. In the present review, the properties and requirements of pharmaceutical dosage forms at the nanoscale, so-called nanomedicines, are been highlighted. An overview of the main current nanomedicines in pre-clinical and clinical development is presented, detailing the challenges to the personalization of these therapies. Next, the process of development of novel nanomedicines is described, from their design in research labs to their arrival on the market, including considerations for the design of nanomedicines adapted to the requirements of the market to achieve safe, effective, and quality products. Finally, attention is given to the point of view of the pharmaceutical industry, including regulation issues applied to the specific case of personalized medicine. The authors expect this review to be a useful overview of the current state of the art of nanomedicine research and industrial production, and the future opportunities of personalized medicine in the upcoming years. The authors encourage the development and marketing of novel personalized nanomedicines.

  4. Personalized Nanomedicine: A Revolution at the Nanoscale

    Science.gov (United States)

    García-Celma, Maria José

    2017-01-01

    Nanomedicine is an interdisciplinary research field that results from the application of nanotechnology to medicine and has the potential to significantly improve some current treatments. Specifically, in the field of personalized medicine, it is expected to have a great impact in the near future due to its multiple advantages, namely its versatility to adapt a drug to a cohort of patients. In the present review, the properties and requirements of pharmaceutical dosage forms at the nanoscale, so-called nanomedicines, are been highlighted. An overview of the main current nanomedicines in pre-clinical and clinical development is presented, detailing the challenges to the personalization of these therapies. Next, the process of development of novel nanomedicines is described, from their design in research labs to their arrival on the market, including considerations for the design of nanomedicines adapted to the requirements of the market to achieve safe, effective, and quality products. Finally, attention is given to the point of view of the pharmaceutical industry, including regulation issues applied to the specific case of personalized medicine. The authors expect this review to be a useful overview of the current state of the art of nanomedicine research and industrial production, and the future opportunities of personalized medicine in the upcoming years. The authors encourage the development and marketing of novel personalized nanomedicines. PMID:29023366

  5. Personalized Nanomedicine: A Revolution at the Nanoscale.

    Science.gov (United States)

    Fornaguera, Cristina; García-Celma, Maria José

    2017-10-12

    Nanomedicine is an interdisciplinary research field that results from the application of nanotechnology to medicine and has the potential to significantly improve some current treatments. Specifically, in the field of personalized medicine, it is expected to have a great impact in the near future due to its multiple advantages, namely its versatility to adapt a drug to a cohort of patients. In the present review, the properties and requirements of pharmaceutical dosage forms at the nanoscale, so-called nanomedicines, are been highlighted. An overview of the main current nanomedicines in pre-clinical and clinical development is presented, detailing the challenges to the personalization of these therapies. Next, the process of development of novel nanomedicines is described, from their design in research labs to their arrival on the market, including considerations for the design of nanomedicines adapted to the requirements of the market to achieve safe, effective, and quality products. Finally, attention is given to the point of view of the pharmaceutical industry, including regulation issues applied to the specific case of personalized medicine. The authors expect this review to be a useful overview of the current state of the art of nanomedicine research and industrial production, and the future opportunities of personalized medicine in the upcoming years. The authors encourage the development and marketing of novel personalized nanomedicines.

  6. Delay dynamics of neuromorphic optoelectronic nanoscale resonators: Perspectives and applications

    Science.gov (United States)

    Romeira, Bruno; Figueiredo, José M. L.; Javaloyes, Julien

    2017-11-01

    With the recent exponential growth of applications using artificial intelligence (AI), the development of efficient and ultrafast brain-like (neuromorphic) systems is crucial for future information and communication technologies. While the implementation of AI systems using computer algorithms of neural networks is emerging rapidly, scientists are just taking the very first steps in the development of the hardware elements of an artificial brain, specifically neuromorphic microchips. In this review article, we present the current state of the art of neuromorphic photonic circuits based on solid-state optoelectronic oscillators formed by nanoscale double barrier quantum well resonant tunneling diodes. We address, both experimentally and theoretically, the key dynamic properties of recently developed artificial solid-state neuron microchips with delayed perturbations and describe their role in the study of neural activity and regenerative memory. This review covers our recent research work on excitable and delay dynamic characteristics of both single and autaptic (delayed) artificial neurons including all-or-none response, spike-based data encoding, storage, signal regeneration and signal healing. Furthermore, the neural responses of these neuromorphic microchips display all the signatures of extended spatio-temporal localized structures (LSs) of light, which are reviewed here in detail. By taking advantage of the dissipative nature of LSs, we demonstrate potential applications in optical data reconfiguration and clock and timing at high-speeds and with short transients. The results reviewed in this article are a key enabler for the development of high-performance optoelectronic devices in future high-speed brain-inspired optical memories and neuromorphic computing.

  7. Common Principles of Molecular Electronics and Nanoscale Electrochemistry.

    Science.gov (United States)

    Bueno, Paulo Roberto

    2018-05-24

    The merging of nanoscale electronics and electrochemistry can potentially modernize the way electronic devices are currently engineered or constructed. It is well known that the greatest challenges will involve not only miniaturizing and improving the performance of mobile devices, but also manufacturing reliable electrical vehicles, and engineering more efficient solar panels and energy storage systems. These are just a few examples of how technological innovation is dependent on both electrochemical and electronic elements. This paper offers a conceptual discussion of this central topic, with particular focus on the impact that uniting physical and chemical concepts at a nanoscale could have on the future development of electroanalytical devices. The specific example to which this article refers pertains to molecular diagnostics, i.e., devices that employ physical and electrochemical concepts to diagnose diseases.

  8. Modeling of nanoscale liquid mixture transport by density functional hydrodynamics

    Science.gov (United States)

    Dinariev, Oleg Yu.; Evseev, Nikolay V.

    2017-06-01

    Modeling of multiphase compositional hydrodynamics at nanoscale is performed by means of density functional hydrodynamics (DFH). DFH is the method based on density functional theory and continuum mechanics. This method has been developed by the authors over 20 years and used for modeling in various multiphase hydrodynamic applications. In this paper, DFH was further extended to encompass phenomena inherent in liquids at nanoscale. The new DFH extension is based on the introduction of external potentials for chemical components. These potentials are localized in the vicinity of solid surfaces and take account of the van der Waals forces. A set of numerical examples, including disjoining pressure, film precursors, anomalous rheology, liquid in contact with heterogeneous surface, capillary condensation, and forward and reverse osmosis, is presented to demonstrate modeling capabilities.

  9. Nanoscale roughness contact in a slider-disk interface.

    Science.gov (United States)

    Hua, Wei; Liu, Bo; Yu, Shengkai; Zhou, Weidong

    2009-07-15

    The nanoscale roughness contact between molecularly smooth surfaces of a slider-disk interface in a hard disk drive is analyzed, and the lubricant behavior at very high shear rate is presented. A new contact model is developed to study the nanoscale roughness contact behavior by classifying various forms of contact into slider-lubricant contact, slider-disk elastic contact and plastic contact. The contact pressure and the contact probabilities of the three types of contact are investigated. The new contact model is employed to explain and provide insight to an interesting experimental result found in a thermal protrusion slider. The protrusion budget for head surfing in the lubricant, which is the ideal state for contact recording, is also discussed.

  10. Nanoscale roughness contact in a slider-disk interface

    International Nuclear Information System (INIS)

    Hua Wei; Liu Bo; Yu Shengkai; Zhou Weidong

    2009-01-01

    The nanoscale roughness contact between molecularly smooth surfaces of a slider-disk interface in a hard disk drive is analyzed, and the lubricant behavior at very high shear rate is presented. A new contact model is developed to study the nanoscale roughness contact behavior by classifying various forms of contact into slider-lubricant contact, slider-disk elastic contact and plastic contact. The contact pressure and the contact probabilities of the three types of contact are investigated. The new contact model is employed to explain and provide insight to an interesting experimental result found in a thermal protrusion slider. The protrusion budget for head surfing in the lubricant, which is the ideal state for contact recording, is also discussed.

  11. Surface Effects on Nanoscale Gas Flows

    Science.gov (United States)

    Beskok, Ali; Barisik, Murat

    2010-11-01

    3D MD simulations of linear Couette flow of argon gas confined within nano-scale channels are performed in the slip, transition and free molecular flow regimes. The velocity and density profiles show deviations from the kinetic theory based predictions in the near wall region that typically extends three molecular diameters (s) from each surface. Utilizing the Irwin-Kirkwood theorem, stress tensor components for argon gas confined in nano-channels are investigated. Outside the 3s region, three normal stress components are identical, and equal to pressure predicted using the ideal gas law, while the shear stress is a constant. Within the 3s region, the normal stresses become anisotropic and the shear stress shows deviations from its bulk value due to the surface virial effects. Utilizing the kinetic theory and MD predicted shear stress values, the tangential momentum accommodation coefficient for argon gas interacting with FCC structured walls (100) plane facing the fluid is calculated to be 0.75; this value is independent of the Knudsen number. Results show emergence of the 3s region as an additional characteristic length scale in nano-confined gas flows.

  12. Facile approach to the fabrication of a micropattern possessing nanoscale substructure.

    Science.gov (United States)

    Ji, Qiang; Jiang, Xuesong; Yin, Jie

    2007-12-04

    On the basis of the combined technologies of photolithography and reaction-induced phase separation (RIPS), a facile approach has been successfully developed for the fabrication of a micropattern possessing nanoscale substructure on the thin film surface. This approach involves three steps. In the first step, a thin film was prepared by spin coating from a solution of a commercial random copolymer, polystyrene-r-poly(methyl methacrylate) (PS-r-PMMA) and a commercial crosslinker, trimethylolpropane triacrylate (TMPTA). In the second step, photolithograph was performed with the thin film using a 250 W high-pressure mercury lamp to produce the micropattern. Finally, the resulting micropattern was annealed at 200 degrees C for a certain time, and reaction-induced phase separation occurred. After soaking in chloroform for 4 h, nanoscale substructure was obtained. The whole processes were traced by atomic force microscopy (AFM), X-ray photoelectron spectrometry (XPS), and Fourier transform infrared (FTIR) spectroscopy, and the results supported the proposed structure.

  13. Cell-specific STORM superresolution imaging reveals nanoscale organization of cannabinoid signaling

    Science.gov (United States)

    Szabó, Szilárd I.; Szabadits, Eszter; Pintér, Balázs; Woodhams, Stephen G.; Henstridge, Christopher M.; Balla, Gyula Y.; Nyilas, Rita; Varga, Csaba; Lee, Sang-Hun; Matolcsi, Máté; Cervenak, Judit; Kacskovics, Imre; Watanabe, Masahiko; Sagheddu, Claudia; Melis, Miriam; Pistis, Marco; Soltesz, Ivan; Katona, István

    2014-01-01

    A major challenge in neuroscience is to determine the nanoscale position and quantity of signaling molecules in a cell-type-, and subcellular compartment-specific manner. We therefore developed a novel approach combining cell-specific physiological and anatomical characterization with superresolution imaging, and studied the molecular and structural parameters shaping the physiological properties of synaptic endocannabinoid signaling in the mouse hippocampus. We found that axon terminals of perisomatically-projecting GABAergic interneurons possess increased CB1 receptor number, active-zone complexity, and receptor/effector ratio compared to dendritically-projecting interneurons, in agreement with higher efficiency of cannabinoid signaling at somatic versus dendritic synapses. Furthermore, chronic Δ9-tetrahydrocannabinol administration, which reduces cannabinoid efficacy on GABA release, evoked dramatic CB1-downregulation in a dose-dependent manner. Full receptor recovery required several weeks after cessation of Δ9-tetrahydrocannabinol treatment. These findings demonstrate that cell-type-specific nanoscale analysis of endogenous protein distribution is possible in brain circuits, and identify novel molecular properties controlling endocannabinoid signaling and cannabis-induced cognitive dysfunction. PMID:25485758

  14. Cell-specific STORM super-resolution imaging reveals nanoscale organization of cannabinoid signaling.

    Science.gov (United States)

    Dudok, Barna; Barna, László; Ledri, Marco; Szabó, Szilárd I; Szabadits, Eszter; Pintér, Balázs; Woodhams, Stephen G; Henstridge, Christopher M; Balla, Gyula Y; Nyilas, Rita; Varga, Csaba; Lee, Sang-Hun; Matolcsi, Máté; Cervenak, Judit; Kacskovics, Imre; Watanabe, Masahiko; Sagheddu, Claudia; Melis, Miriam; Pistis, Marco; Soltesz, Ivan; Katona, István

    2015-01-01

    A major challenge in neuroscience is to determine the nanoscale position and quantity of signaling molecules in a cell type- and subcellular compartment-specific manner. We developed a new approach to this problem by combining cell-specific physiological and anatomical characterization with super-resolution imaging and studied the molecular and structural parameters shaping the physiological properties of synaptic endocannabinoid signaling in the mouse hippocampus. We found that axon terminals of perisomatically projecting GABAergic interneurons possessed increased CB1 receptor number, active-zone complexity and receptor/effector ratio compared with dendritically projecting interneurons, consistent with higher efficiency of cannabinoid signaling at somatic versus dendritic synapses. Furthermore, chronic Δ(9)-tetrahydrocannabinol administration, which reduces cannabinoid efficacy on GABA release, evoked marked CB1 downregulation in a dose-dependent manner. Full receptor recovery required several weeks after the cessation of Δ(9)-tetrahydrocannabinol treatment. These findings indicate that cell type-specific nanoscale analysis of endogenous protein distribution is possible in brain circuits and identify previously unknown molecular properties controlling endocannabinoid signaling and cannabis-induced cognitive dysfunction.

  15. Molecular Clusters: Nanoscale Building Blocks for Solid-State Materials.

    Science.gov (United States)

    Pinkard, Andrew; Champsaur, Anouck M; Roy, Xavier

    2018-04-17

    The programmed assembly of nanoscale building blocks into multicomponent hierarchical structures is a powerful strategy for the bottom-up construction of functional materials. To develop this concept, our team has explored the use of molecular clusters as superatomic building blocks to fabricate new classes of materials. The library of molecular clusters is rich with exciting properties, including diverse functionalization, redox activity, and magnetic ordering, so the resulting cluster-assembled solids, which we term superatomic crystals (SACs), hold the promise of high tunability, atomic precision, and robust architectures among a diverse range of other material properties. Molecular clusters have only seldom been used as precursors for functional materials. Our team has been at the forefront of new developments in this exciting research area, and this Account focuses on our progress toward designing materials from cluster-based precursors. In particular, this Account discusses (1) the design and synthesis of molecular cluster superatomic building blocks, (2) their self-assembly into SACs, and (3) their resulting collective properties. The set of molecular clusters discussed herein is diverse, with different cluster cores and ligand arrangements to create an impressive array of solids. The cluster cores include octahedral M 6 E 8 and cubane M 4 E 4 (M = metal; E = chalcogen), which are typically passivated by a shell of supporting ligands, a feature upon which we have expanded upon by designing and synthesizing more exotic ligands that can be used to direct solid-state assembly. Building from this library, we have designed whole families of binary SACs where the building blocks are held together through electrostatic, covalent, or van der Waals interactions. Using single-crystal X-ray diffraction (SCXRD) to determine the atomic structure, a remarkable range of compositional variability is accessible. We can also use this technique, in tandem with vibrational

  16. Structuring user-centred product development processes

    NARCIS (Netherlands)

    Hoolhorst, F.W.B.

    2012-01-01

    Within the last decades, product development industry has found itself facing a general increase in product use problems. These problems originate from a mismatch between the actual functionality that the product provides and the afforded product-user interaction versus the user’s expectations

  17. Leading Change: Faculty Development through Structured Collaboration

    Directory of Open Access Journals (Sweden)

    Suzanne Painter

    2015-06-01

    Full Text Available There are relentless calls for innovation in higher education programs in response to media and policy-makers attention to such concerns as instructional quality, relevance to employment, costs, and time-to-degree. At the same time, the individual course remains the primary unit of instruction and there is little evidence of faculty development strategies to assist with changing core instructional practices. We faced that dilemma when we led an innovative doctoral program in educational leadership. Soon after beginning, we implemented a regular meeting of all faculty members teaching and advising in the program to address upcoming events and review student progress. Our retrospective analysis indicates that these meetings evolved as a practical and sustainable framework for faculty development in support of deep change for instructional practices. Here we describe the challenge of faculty development for change and draw lessons learned from our four years of leadership centered on experiential learning and community sense-making. We hope that program leaders who aspire to promote faculty development in conjunction with graduate program implementation will find these lessons useful.

  18. Micro- and nanoscale devices for the investigation of epigenetics and chromatin dynamics

    Science.gov (United States)

    Aguilar, Carlos A.; Craighead, Harold G.

    2013-10-01

    Deoxyribonucleic acid (DNA) is the blueprint on which life is based and transmitted, but the way in which chromatin -- a dynamic complex of nucleic acids and proteins -- is packaged and behaves in the cellular nucleus has only begun to be investigated. Epigenetic modifications sit 'on top of' the genome and affect how DNA is compacted into chromatin and transcribed into ribonucleic acid (RNA). The packaging and modifications around the genome have been shown to exert significant influence on cellular behaviour and, in turn, human development and disease. However, conventional techniques for studying epigenetic or conformational modifications of chromosomes have inherent limitations and, therefore, new methods based on micro- and nanoscale devices have been sought. Here, we review the development of these devices and explore their use in the study of DNA modifications, chromatin modifications and higher-order chromatin structures.

  19. Nanoscale hydroxyapatite particles for bone tissue engineering.

    Science.gov (United States)

    Zhou, Hongjian; Lee, Jaebeom

    2011-07-01

    Hydroxyapatite (HAp) exhibits excellent biocompatibility with soft tissues such as skin, muscle and gums, making it an ideal candidate for orthopedic and dental implants or components of implants. Synthetic HAp has been widely used in repair of hard tissues, and common uses include bone repair, bone augmentation, as well as coating of implants or acting as fillers in bone or teeth. However, the low mechanical strength of normal HAp ceramics generally restricts its use to low load-bearing applications. Recent advancements in nanoscience and nanotechnology have reignited investigation of nanoscale HAp formation in order to clearly define the small-scale properties of HAp. It has been suggested that nano-HAp may be an ideal biomaterial due to its good biocompatibility and bone integration ability. HAp biomedical material development has benefited significantly from advancements in nanotechnology. This feature article looks afresh at nano-HAp particles, highlighting the importance of size, crystal morphology control, and composites with other inorganic particles for biomedical material development. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Retail Market Structure Development in Central Europe

    Directory of Open Access Journals (Sweden)

    Martin Machek

    2012-12-01

    Full Text Available This article is analyzing the trends and development in the retailing sector in Central Europe, namely in the Czech Republic, Hungary, Poland and Slovakia. These markets serve about 63 million inhabitants. The retail industry in Central Europe has changed dramatically in the last two decades, and has become a model for successful transformation of emerging markets. The retail market is highly concentrated and dominated by Western European retail chains. International retail chains are using all formats of modern distribution. This article is focusing on the development of hypermarkets, supermarkets and discount stores. Due to the international retail chains, Central European countries benefit from a dense network of modern shopping places; the intense competition of highly productive retailers contributes to the lower level of inflation rate because of the so-called Wal-Mart Effect. The constant pressure on prices influences the marketing strategies of both retailers and suppliers.

  1. Glass of monatomic Lennard-Jones system at nanoscale

    International Nuclear Information System (INIS)

    Vo Van Hoang

    2010-01-01

    Structure and stability of glass of monatomic Lennard-Jones (LJ) system at nanoscale compared with those of the bulk counterparts have been studied using the classical molecular dynamics (MD) method. Models have been obtained by cooling from the melts. Structure of the systems was analyzed via radial distribution function (RDF), interatomic distances, the Honeycutt-Andersen analysis and coordination number distributions. Surface and core structures of LJ nanoparticles have been analyzed in details. Density dependence and cooling rate effects on structure of the systems have been found and discussed. In addition, size dependence of structure and properties of nanoparticles has been analyzed in detail. Indeed, we found glass formation in monatomic LJ systems; however, their stability is not high. Evolution of structure and thermodynamics of the systems upon cooling from the melts was found. We also discussed annealing-induced crystallization of LJ glass.

  2. EDITORIAL: Physical behaviour at the nanoscale: a model for fertile research Physical behaviour at the nanoscale: a model for fertile research

    Science.gov (United States)

    Demming, Anna

    2013-06-01

    At the nanoscale physics follows familiar principles that lead to unfamiliar and even unlikely responses. The change in the balance of a range of physical features results in behaviour that can differ wildly from the same materials at the macroscale. In this issue Di Ventra and Pershin examine some of the memory effects that have attracted increasing interest in investigations of nanoscale electronic systems [1]. The work builds on the familiar premise that external perturbations cannot have an instantaneous effect on any condensed matter system. As they point out, 'This is even more so in systems of nanoscale dimensions where the dynamics of a few atoms may affect the whole structure dramatically'. In this way they explain that the response of these systems will always have some degree of memory present and that memristive, memcapacitive and meminductive systems are simply examples where this feature is particularly prominent. In the late 1990s investigations into the use of carbon nanotubes and SiC nanorods revealed that the moduli of these structures changes with diameter, highlighting the eccentricities of mechanical properties at the nanoscale. These results prompted Miller at the University of Saskatchewan and Shenoy at the Indian Institute of Technology to study the properties of nanotubes and nanorods in detail [2]. 'In the eyes of an engineer these structures are essentially little beams', they explained, 'Albeit they are "little" to a degree that challenges our traditional notions of continuum mechanics'. In their work they developed one of the first simple models for explaining the behaviour of the Young's modulus of nanostructures, verified by direct atomistic simulation of axial loading of these structures. Since then, consideration of different nanoscale structures and the dissipation of energy under stress and strain have also demystified the extraordinary mechanical properties of natural materials such as collagen [3] and spider's silk [4]. The

  3. Nanoscale heat transfer in carbon nanotube - sugar alcohol composites as heat storage materials

    NARCIS (Netherlands)

    Zhang, H.; Rindt, C.C.M.; Smeulders, D.M.J.; Gaastra - Nedea, S.V.

    2016-01-01

    Nanoscale carbon structures such as graphene and carbon nanotubes (CNTs) can greatly improve the effective thermal conductivity of thermally sluggish heat storage materials, such as sugar alcohols (SAs). The specific improvement depends on the heat transfer rate across the carbon structure. Besides,

  4. Developing a network-level structural capacity index for structural evaluation of pavements.

    Science.gov (United States)

    2013-03-01

    The objective of this project was to develop a structural index for use in network-level pavement evaluation to facilitate : the inclusion of the pavements structural condition in pavement management applications. The primary goal of network-level...

  5. Two-dimensional threshold voltage model and design considerations for gate electrode work function engineered recessed channel nanoscale MOSFET: I

    International Nuclear Information System (INIS)

    Chaujar, Rishu; Kaur, Ravneet; Gupta, Mridula; Gupta, R S; Saxena, Manoj

    2009-01-01

    This paper discusses a threshold voltage model for novel device structure: gate electrode work function engineered recessed channel (GEWE-RC) nanoscale MOSFET, which combines the advantages of both RC and GEWE structures. In part I, the model accurately predicts (a) surface potential, (b) threshold voltage and (c) sub-threshold slope for single material gate recessed channel (SMG-RC) and GEWE-RC structures. Part II focuses on the development of compact analytical drain current model taking into account the transition regimes from sub-threshold to saturation. Furthermore, the drain conductance evaluation has also been obtained, reflecting relevance of the proposed device for analogue design. The analysis takes into account the effect of gate length and groove depth in order to develop a compact model suitable for device design. The analytical results predicted by the model confirm well with the simulated results. Results in part I also provide valuable design insights in the performance of nanoscale GEWE-RC MOSFET with optimum threshold voltage and negative junction depth (NJD), and hence serves as a tool to optimize important device and technological parameters for 40 nm technology

  6. A structural analysis of Japanese economic development

    OpenAIRE

    Tsujimura, Kazusuke; Tsujimura, Masako

    2018-01-01

    Japan successfully escaped from poverty after the world war and attained prosperity in a matter of two decades. There were two keys for the success. One was the priority production system – the idea to develop the industries at the bottom of the triangulated input-output table first, and to climb the triangle step by step. The second key for the success was the country’s unique financial system; they deliberately grew both long-term financial institutions for large enterprises and local credi...

  7. Abstractocyte: A Visual Tool for Exploring Nanoscale Astroglial Cells

    KAUST Repository

    Mohammed, Haneen; Al-Awami, Ali K.; Beyer, Johanna; Cali, Corrado; Magistretti, Pierre J.; Pfister, Hanspeter; Hadwiger, Markus

    2017-01-01

    This paper presents Abstractocyte, a system for the visual analysis of astrocytes and their relation to neurons, in nanoscale volumes of brain tissue. Astrocytes are glial cells, i.e., non-neuronal cells that support neurons and the nervous system. The study of astrocytes has immense potential for understanding brain function. However, their complex and widely-branching structure requires high-resolution electron microscopy imaging and makes visualization and analysis challenging. Furthermore, the structure and function of astrocytes is very different from neurons, and therefore requires the development of new visualization and analysis tools. With Abstractocyte, biologists can explore the morphology of astrocytes using various visual abstraction levels, while simultaneously analyzing neighboring neurons and their connectivity. We define a novel, conceptual 2D abstraction space for jointly visualizing astrocytes and neurons. Neuroscientists can choose a specific joint visualization as a point in this space. Interactively moving this point allows them to smoothly transition between different abstraction levels in an intuitive manner. In contrast to simply switching between different visualizations, this preserves the visual context and correlations throughout the transition. Users can smoothly navigate from concrete, highly-detailed 3D views to simplified and abstracted 2D views. In addition to investigating astrocytes, neurons, and their relationships, we enable the interactive analysis of the distribution of glycogen, which is of high importance to neuroscientists. We describe the design of Abstractocyte, and present three case studies in which neuroscientists have successfully used our system to assess astrocytic coverage of synapses, glycogen distribution in relation to synapses, and astrocytic-mitochondria coverage.

  8. Abstractocyte: A Visual Tool for Exploring Nanoscale Astroglial Cells

    KAUST Repository

    Mohammed, Haneen

    2017-08-28

    This paper presents Abstractocyte, a system for the visual analysis of astrocytes and their relation to neurons, in nanoscale volumes of brain tissue. Astrocytes are glial cells, i.e., non-neuronal cells that support neurons and the nervous system. The study of astrocytes has immense potential for understanding brain function. However, their complex and widely-branching structure requires high-resolution electron microscopy imaging and makes visualization and analysis challenging. Furthermore, the structure and function of astrocytes is very different from neurons, and therefore requires the development of new visualization and analysis tools. With Abstractocyte, biologists can explore the morphology of astrocytes using various visual abstraction levels, while simultaneously analyzing neighboring neurons and their connectivity. We define a novel, conceptual 2D abstraction space for jointly visualizing astrocytes and neurons. Neuroscientists can choose a specific joint visualization as a point in this space. Interactively moving this point allows them to smoothly transition between different abstraction levels in an intuitive manner. In contrast to simply switching between different visualizations, this preserves the visual context and correlations throughout the transition. Users can smoothly navigate from concrete, highly-detailed 3D views to simplified and abstracted 2D views. In addition to investigating astrocytes, neurons, and their relationships, we enable the interactive analysis of the distribution of glycogen, which is of high importance to neuroscientists. We describe the design of Abstractocyte, and present three case studies in which neuroscientists have successfully used our system to assess astrocytic coverage of synapses, glycogen distribution in relation to synapses, and astrocytic-mitochondria coverage.

  9. Development of mechanical structure design technology for LMR

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Bong; Lee, Jae Han; Joo, Young Sang [and others

    2000-05-01

    In this project, fundamentals for conceptual design of mechanical structure system for LMR are independently established. The research contents are as follow; at first, conceptual design for SSC, design integration of interfaces, design consistency to keep functions and interfaces by developing arrangement of reactor system and 3 dimensional concept drawings, development and revision of preliminary design requirements and structural design basis, and evaluation of structural integrity for SSC following structural design criteria to check the conceptual design to be proper, at second, development of high temperature structure design and analysis technology and establishment of high temperature structural analysis codes and scheme, development of seismic isolation design concept to reduce seismic design loads to SCC and establishment of seismic analysis codes and scheme.

  10. Development of mechanical structure design technology for LMR

    International Nuclear Information System (INIS)

    Yoo, Bong; Lee, Jae Han; Joo, Young Sang

    2000-05-01

    In this project, fundamentals for conceptual design of mechanical structure system for LMR are independently established. The research contents are as follow; at first, conceptual design for SSC, design integration of interfaces, design consistency to keep functions and interfaces by developing arrangement of reactor system and 3 dimensional concept drawings, development and revision of preliminary design requirements and structural design basis, and evaluation of structural integrity for SSC following structural design criteria to check the conceptual design to be proper, at second, development of high temperature structure design and analysis technology and establishment of high temperature structural analysis codes and scheme, development of seismic isolation design concept to reduce seismic design loads to SCC and establishment of seismic analysis codes and scheme

  11. Development of analysis methods for seismically isolated nuclear structures

    International Nuclear Information System (INIS)

    Yoo, Bong; Lee, Jae-Han; Koo, Gyeng-Hoi

    2002-01-01

    KAERI's contributions to the project entitled Development of Analysis Methods for Seismically Isolated Nuclear Structures under IAEA CRP of the intercomparison of analysis methods for predicting the behaviour of seismically isolated nuclear structures during 1996-1999 in effort to develop the numerical analysis methods and to compare the analysis results with the benchmark test results of seismic isolation bearings and isolated nuclear structures provided by participating countries are briefly described. Certain progress in the analysis procedures for isolation bearings and isolated nuclear structures has been made throughout the IAEA CRPs and the analysis methods developed can be improved for future nuclear facility applications. (author)

  12. Exploring Ultimate Water Capillary Evaporation in Nanoscale Conduits.

    Science.gov (United States)

    Li, Yinxiao; Alibakhshi, Mohammad Amin; Zhao, Yihong; Duan, Chuanhua

    2017-08-09

    Capillary evaporation in nanoscale conduits is an efficient heat/mass transfer strategy that has been widely utilized by both nature and mankind. Despite its broad impact, the ultimate transport limits of capillary evaporation in nanoscale conduits, governed by the evaporation/condensation kinetics at the liquid-vapor interface, have remained poorly understood. Here we report experimental study of the kinetic limits of water capillary evaporation in two dimensional nanochannels using a novel hybrid channel design. Our results show that the kinetic-limited evaporation fluxes break down the limits predicated by the classical Hertz-Knudsen equation by an order of magnitude, reaching values up to 37.5 mm/s with corresponding heat fluxes up to 8500 W/cm 2 . The measured evaporation flux increases with decreasing channel height and relative humidity but decreases as the channel temperature decreases. Our findings have implications for further understanding evaporation at the nanoscale and developing capillary evaporation-based technologies for both energy- and bio-related applications.

  13. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Borghi, F.; Lenardi, C.; Podestà, A.; Milani, P., E-mail: pmilani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Sogne, E. [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); European School of Molecular Medicine (SEMM), IFOM-IEO, Milano (Italy); Merlini, M. [Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, via Mangiagalli 32, 20133 Milano (Italy); Ducati, C. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2016-08-07

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments.

  14. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    International Nuclear Information System (INIS)

    Borghi, F.; Lenardi, C.; Podestà, A.; Milani, P.; Sogne, E.; Merlini, M.; Ducati, C.

    2016-01-01

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments.

  15. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    KAUST Repository

    Borghi, F.; Sogne, Elisa; Lenardi, C.; Podestà , A.; Merlini, M.; Ducati, C.; Milani, P.

    2016-01-01

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing.

  16. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    KAUST Repository

    Borghi, F.

    2016-08-05

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing.

  17. Nanoscale Test Strips for Multiplexed Blood Analysis

    Science.gov (United States)

    Chan, Eugene

    2015-01-01

    A critical component of the DNA Medicine Institute's Reusable Handheld Electrolyte and Lab Technology for Humans (rHEALTH) sensor are nanoscale test strips, or nanostrips, that enable multiplexed blood analysis. Nanostrips are conceptually similar to the standard urinalysis test strip, but the strips are shrunk down a billionfold to the microscale. Each nanostrip can have several sensor pads that fluoresce in response to different targets in a sample. The strips carry identification tags that permit differentiation of a specific panel from hundreds of other nanostrip panels during a single measurement session. In Phase I of the project, the company fabricated, tested, and demonstrated functional parathyroid hormone and vitamin D nanostrips for bone metabolism, and thrombin aptamer and immunoglobulin G antibody nanostrips. In Phase II, numerous nanostrips were developed to address key space flight-based medical needs: assessment of bone metabolism, immune response, cardiac status, liver metabolism, and lipid profiles. This unique approach holds genuine promise for space-based portable biodiagnostics and for point-of-care (POC) health monitoring and diagnostics here on Earth.

  18. The Structure of the Managerial System of Higher Education's Development

    Science.gov (United States)

    Levina, Elena Y.; Kutuev, Ruslan A.; Balakhnina, Lidia V.; Tumarov, Konstantin B.; Chudnovskiy, Alexey D.; Shagiev, ?ulat V.

    2016-01-01

    The research urgency is caused by necessity of planning regulation of higher education development at all levels of management. The purpose of this article is to develop the structure of a control system of higher education development, the Foundation of which is understanding of the quality of higher education as factor for development of the…

  19. Analytical TEM investigations of nanoscale magnetic materials

    International Nuclear Information System (INIS)

    Meingast, A.

    2015-01-01

    element identification or, an absolute quantification is possible. Moreover, the parallel acquisition of EDXS and EELS signals allows combining the strength of each respective technique. A careful and precise sample preparation is crucial and knowledge and suitable methods had to be developed. Preparation induced modifications of the investigated material was minimized by identifying changes to the material during thinning to electron transparency. Reducing surface amorphization of TEM specimens and moreover identifying and quantifying surface oxidation was an important factor. Questions regarding the structural architecture of three diverse magnetic materials down to the atomic level have been addressed, and elemental distributions have been determined quantitatively. The first part of the results treats structural and analytical results of crystalline nanocubes. These cubes have dimensions below 30 nm, and represent a class of materials to exploit magnetic exchange coupling on a nanometer scale. Knowledge about the elemental distribution on a nanometer basis within a nanocube is necessary to tailor the magnetic properties. Analytical investigations deal with the determination of the oxidation state of iron oxide reference nanocrystals and the elemental distribution within a multi-component system. Transition metal doped gallium nitride (GaN) falling into the class of dilute magnetic semiconductors was investigated by various high resolution imaging techniques and spectroscopic methods for resolving morphologies and dopant concentrations. The doping of GaN is intended to provide additional magnetic functionalities to the semiconducting material used for future spintronic devices. Quantitative EELS measurements resolved that Mn was incorporated either in a homogeneous way or added to GaN in a pulsed way, leading to a layered doping. Iron was used as another potential dopant for GaN. Hereby specific growth procedures enabled the formation of a layer of iron

  20. Nanoscale transformation of sp2 to sp3 of graphite by slow highly charged ion irradiation

    International Nuclear Information System (INIS)

    Meguro, T.; Hida, A.; Koguchi, Y.; Miyamoto, S.; Yamamoto, Y.; Takai, H.; Maeda, K.; Aoyagi, Y.

    2003-01-01

    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 2 to sp 3 hybridization in graphite, resulting in the formation of nanoscale diamond-like structures (nanodiamond) at the impact region. From Raman spectroscopic measurements on sp 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

  1. FDTD based model of ISOCT imaging for validation of nanoscale sensitivity (Conference Presentation)

    Science.gov (United States)

    Eid, Aya; Zhang, Di; Yi, Ji; Backman, Vadim

    2017-02-01

    Many of the earliest structural changes associated with neoplasia occur on the micro and nanometer scale, and thus appear histologically normal. Our group has established Inverse Spectroscopic OCT (ISOCT), a spectral based technique to extract nanoscale sensitive metrics derived from the OCT signal. Thus, there is a need to model light transport through relatively large volumes (< 50 um^3) of media with nanoscale level resolution. Finite Difference Time Domain (FDTD) is an iterative approach which directly solves Maxwell's equations to robustly estimate the electric and magnetic fields propagating through a sample. The sample's refractive index for every spatial voxel and wavelength are specified upon a grid with voxel sizes on the order of λ/20, making it an ideal modelling technique for nanoscale structure analysis. Here, we utilize the FDTD technique to validate the nanoscale sensing ability of ISOCT. The use of FDTD for OCT modelling requires three components: calculating the source beam as it propagates through the optical system, computing the sample's scattered field using FDTD, and finally propagating the scattered field back through the optical system. The principles of Fourier optics are employed to focus this interference field through a 4f optical system and onto the detector. Three-dimensional numerical samples are generated from a given refractive index correlation function with known parameters, and subsequent OCT images and mass density correlation function metrics are computed. We show that while the resolvability of the OCT image remains diffraction limited, spectral analysis allows nanoscale sensitive metrics to be extracted.

  2. 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.

  3. Radiation synthesis of the nano-scale materials

    Energy Technology Data Exchange (ETDEWEB)

    Yonghong, Ni; Zhicheng, Zhang; Xuewu, Ge; Xiangling, Xu [Department of Applied Chemistry, Univ. of Science and Technology of China, Hefei (China)

    2000-03-01

    Some recent research jobs on fabricating the nano-scale materials via {gamma}-irradiation in our laboratory are simply summarized in this paper. The main contents contain four aspects: (1) the preparation of metal alloy - powders; (2) the fabrication of polymer -metal nano-composites in aqueous solution, micro-emulsion and emulsion systems; (3) the synthesis of metal sulfide nano-particles and (4) the preparation of the ordered nano-structure materials. The corresponding preparation processes are also simply described. (author)

  4. Radiation synthesis of the nano-scale materials

    International Nuclear Information System (INIS)

    Ni Yonghong; Zhang Zhicheng; Ge Xuewu; Xu Xiangling

    2000-01-01

    Some recent research jobs on fabricating the nano-scale materials via γ-irradiation in our laboratory are simply summarized in this paper. The main contents contain four aspects: (1) the preparation of metal alloy - powders; (2) the fabrication of polymer -metal nano-composites in aqueous solution, micro-emulsion and emulsion systems; (3) the synthesis of metal sulfide nano-particles and (4) the preparation of the ordered nano-structure materials. The corresponding preparation processes are also simply described. (author)

  5. Nanoscale Resolution 3D Printing with Pin-Modified Electrified Inkjets for Tailorable Nano/Macrohybrid Constructs for Tissue Engineering.

    Science.gov (United States)

    Kim, Jeong In; Kim, Cheol Sang

    2018-04-18

    Cells respond to their microenvironment, which is of a size comparable to that of the cells. The macroscale features of three-dimensional (3D) printing struts typically result in whole cell contact guidance (CCG). In contrast, at the nanoscale, where features are of a size similar to that of receptors of cells, the response of cells is more complex. The cell-nanotopography interaction involves nanoscale adhesion localized structures, which include cell adhesion-related particles that change in response to the clustering of integrin. For this reason, it is necessary to develop a technique for manufacturing tailorable nano/macrohybrid constructs capable of freely controlling the cellular activity. In this study, a hierarchical 3D nano- to microscale hybrid structure was fabricated by combinational processing of 3D printing and electrified inkjet spinning via pin motions. This method overcomes the disadvantages of conventional 3D printing, providing a novel combinatory technique for the fabrication of 3D hybrid constructs with excellent cell proliferation. Through a pin-modified electrified inkjet spinning, we have successfully fabricated customizable nano-/microscale hybrid constructs in a fibrous or mesh form, which can control the cell fate. We have conducted this study of cell-topography interactions from the fabrication approach to accelerate the development of next-generation 3D scaffolds.

  6. Optical Biosensors: A Revolution Towards Quantum Nanoscale Electronics Device Fabrication

    Directory of Open Access Journals (Sweden)

    D. Dey

    2011-01-01

    Full Text Available The dimension of biomolecules is of few nanometers, so the biomolecular devices ought to be of that range so a better understanding about the performance of the electronic biomolecular devices can be obtained at nanoscale. Development of optical biomolecular device is a new move towards revolution of nano-bioelectronics. Optical biosensor is one of such nano-biomolecular devices that has a potential to pave a new dimension of research and device fabrication in the field of optical and biomedical fields. This paper is a very small report about optical biosensor and its development and importance in various fields.

  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. Development and modeling of self-deployable structures

    Science.gov (United States)

    Neogi, Depankar

    Deployable space structures are prefabricated structures which can be transformed from a closed, compact configuration to a predetermined expanded form in which they are stable and can bear loads. The present research effort investigates a new family of deployable structures, called the Self-Deployable Structures (SDS). Unlike other deployable structures, which have rigid members, the SDS members are flexible while the connecting joints are rigid. The joints store the predefined geometry of the deployed structure in the collapsed state. The SDS is stress-free in both deployed and collapsed configurations and results in a self-standing structure which acquires its structural properties after a chemical reaction. Reliability of deployment is one of the most important features of the SDS, since it does not rely on mechanisms that can lock during deployment. The unit building block of these structures is the self-deployable structural element (SDSE). Several SDSE members can be linked to generate a complex building block such as a triangular or a tetrahedral structure. Different SDSE and SDS concepts are investigated in the research work, and the performance of SDS's are experimentally and theoretically explored. Triangular and tetrahedral prototype SDS have been developed and presented. Theoretical efforts include modeling the behavior of 2-dimensional SDSs. Using this design tool, engineers can study the effects of different packing configurations and deployment sequence; and perform optimization on the collapsed state of a structure with different external constraints. The model also predicts if any lockup or entanglement occurs during deployment.

  9. Development of Cranial Bone Surrogate Structures Using Stereolithographic Additive Manufacturing

    Science.gov (United States)

    2017-09-29

    Additive Manufacturing by Jared M Gardner and Thomas A Plaisted Approved for public release; distribution is unlimited...Laboratory Development of Cranial Bone Surrogate Structures Using Stereolithographic Additive Manufacturing by Thomas A Plaisted Weapons...Structures Using Stereolithographic Additive Manufacturing 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Jared

  10. Changes in Nuclear Structure During Wheat Endosperm Development

    NARCIS (Netherlands)

    Wegel, E.

    2005-01-01

    This thesis is an investigation into the structure of wheat endosperm nuclei starting with nuclear divisions and migration during syncytium formation followed by the development of nuclear shape and positioning of chromosome territories and ending with changes in subchromosomal structure during the

  11. Integrating personality structure, personality process, and personality development

    NARCIS (Netherlands)

    Baumert, Anna; Schmitt, Manfred; Perugini, Marco; Johnson, Wendy; Blum, Gabriela; Borkenau, Peter; Costantini, Giulio; Denissen, J.J.A.; Fleeson, William; Grafton, Ben; Jayawickreme, Eranda; Kurzius, Elena; MacLeod, Colin; Miller, Lynn C.; Read, Stephen J.; Robinson, Michael D.; Wood, Dustin; Wrzus, Cornelia

    2017-01-01

    In this target article, we argue that personality processes, personality structure, and personality development have to be understood and investigated in integrated ways in order to provide comprehensive responses to the key questions of personality psychology. The psychological processes and

  12. Improved tank car design development : ongoing studies on sandwich structures

    Science.gov (United States)

    2009-03-02

    The Government and industry have a common interest in : improving the safety performance of railroad tank cars carrying : hazardous materials. Research is ongoing to develop strategies : to maintain the structural integrity of railroad tank cars carr...

  13. Development of Hybrid Product Breakdown Structure for NASA Ground Systems

    Science.gov (United States)

    Monaghan, Mark W.; Henry, Robert J.

    2013-01-01

    The Product Breakdown Structure is traditionally a method of identification of the products of a project in a tree structure. It is a tool used to assess, plan, document, and display the equipment requirements for a project. It is part of a product based planning technique, and attempts to break down all components of a project in as much detail as possible, so that nothing is overlooked. The PBS for ground systems at the Kennedy Space Center is being developed to encompass the traditional requirements including the alignment of facility, systems, and components to the organizational hierarchy. The Ground Operations Product Breakdown Structure is a hybrid in nature in that some aspects of a work breakdown structure will be incorporated and merged with the Architecture Concept of Operations, Master Subsystem List, customer interface, and assigned management responsibility. The Ground Operations Product Breakdown Structure needs to be able to identify the flexibility of support differing customers (internal and external) usage of ground support equipment within the Kennedy Space Center launch and processing complex. The development of the Product Breakdown Structure is an iterative activity Initially documenting the organization hierarchy structure and relationships. The Product Breakdown Structure identifies the linkage between the customer program requirements, allocation of system resources, development of design goals, and identification logistics products. As the Product Breakdown Structure progresses the incorporation of the results of requirement planning for the customer occurs identifying facility needs and systems. The mature Product Breakdown Structure is baselined with a hierarchical drawing, the Product Breakdown Structure database, and an associated document identifying the verification of the data through the life cycle of the program/product line. This paper will document, demonstrate, and identify key aspects of the life cycle of a Hybrid Product

  14. Design development of graphite primary structures enables SSTO success

    Science.gov (United States)

    Biagiotti, V. A.; Yahiro, J. S.; Suh, Daniel E.; Hodges, Eric R.; Prior, Donald J.

    1997-01-01

    This paper describes the development of a graphite composite wing and a graphite composite intertank primary structure for application toward Single-Stage to Orbit space vehicles such as those under development in NASA's X-33/Reusable Launch Vehicle (RLV) Program. The trade study and designs are based on a Rockwell vertical take-off and horizontal landing (VTHL) wing-body RLV vehicle. Northrop Grumman's approach using a building block development technique is described. Composite Graphite/Bismaleimide (Gr/BMI) material characterization test results are presented. Unique intertank and wing composite subcomponent test article designs are described and test results to date are presented. Wing and intertank Full Scale Section Test Article (FSTA) objectives and designs are outlined. Trade studies, supporting building block testing, and FSTA demonstrations combine to develop graphite primary structure composite technology that enables developing X-33/RLV design programs to meet critical SSTO structural weight and operations performance criteria.

  15. Monitoring structure development in milk acidification using diffuse reflectance profiles

    DEFF Research Database (Denmark)

    Skytte, Jacob Lercke; Andersen, Ulf; Møller, Flemming

    2012-01-01

    are needed so that the production can be carried out consistently, regardless of day-to-day variations in the raw materials. Casein micelles aggregate during milk acidification, which leads to formation of a gel network. This change of structure is important for the development of a range of dairy products......, protein, and temperature in the acidification process is conducted. The purpose of the experiment is to investigate how the change of these parameters affects the diffuse reflectance properties as well as to demonstrate the relation between the optical parameters and structure formation in milk......The structure of dairy products is important for the consumer, and milk acidification plays a central role for structural development. To ensure the best possible consumer experience, it is important that a product’s structural properties are stable. Therefore process and quality control tools...

  16. Development of XAFS Into a Structure Determination Technique

    Science.gov (United States)

    Stern, E. A.

    After the detection of diffraction of x-rays by M. Laue in 1912, the technique was soon applied to structure determination by Bragg within a year. On the other hand, although the edge steps in X-Ray absorption were discovered even earlier by Barkla and both the near edge (XANES) and extended X-Ray fine structure (EXAFS) past the edge were detected by 1929, it still took over 40 years to realize the structure information contained in this X-Ray absorption fine structure (XAFS). To understand this delay a brief historical review of the development of the scientific ideas that transformed XAFS into the premiere technique for local structure determination is given. The development includes both advances in theoretical understanding and calculational capabilities, and in experimental facilities, especially synchrotron radiation sources. The present state of the XAFS technique and its capabilities are summarized.

  17. Self-assembly of nanoscale particles with biosurfactants and membrane scaffold proteins.

    Science.gov (United States)

    Faas, Ramona; Pohle, Annelie; Moß, Karin; Henkel, Marius; Hausmann, Rudolf

    2017-12-01

    Nanodiscs are membrane mimetics which may be used as tools for biochemical and biophysical studies of a variety of membrane proteins. These nanoscale structures are composed of a phospholipid bilayer held together by an amphipathic membrane scaffold protein (MSP). In the past, nanodiscs were successfully assembled with membrane scaffold protein 1D1 and 1,2-dipalmitoyl- sn -glycero-3-phosphorylcholine with a homogeneous diameter of ∼10 nm. In this study, the formation of nanoscale particles from MSP1D1 and rhamnolipid biosurfactants is investigated. Different protein to lipid ratios of 1:80, 1:90 and 1:100 were used for the assembly reaction, which were consecutively separated, purified and analyzed by size-exclusion chromatography (SEC) and dynamic light scattering (DLS). Size distributions were measured to determine homogeneity and confirm size dimensions. In this study, first evidence is presented on the formation of nanoscale particles with rhamnolipid biosurfactants and membrane scaffold proteins.

  18. In situ observations of crack arrest and bridging by nanoscale twins in copper thin films

    International Nuclear Information System (INIS)

    Kim, Seong-Woong; Li Xiaoyan; Gao Huajian; Kumar, Sharvan

    2012-01-01

    In situ tensile experiments in a transmission electron microscope revealed that micro-cracks in ultrafine grained, free-standing, thin copper foils containing nanoscale twins initiated in matrix domains separated by the twins and then arrested at twin boundaries as twin boundary sliding proceeded. The adjacent microcracks eventually coalesced through shear failure of the bridging twins. To investigate the atomic mechanism of this rarely seen nanoscale crack bridging behavior, molecular dynamics simulations were performed to show that during crack propagation twin boundaries are impinged upon by numerous dislocations from the plastically deforming matrix. These dislocations react at the interface and evolve into substantially impenetrable dislocation walls that strongly confine crack nucleation and resist crack propagation, leading to the experimentally observed crack bridging behavior. The present results raise an approach to significantly toughening polycrystalline thin films by incorporating nanoscale twin structures into individual grains that serve as crack bridging ligaments.

  19. Linear arrangement of nano-scale magnetic particles formed in Cu-Fe-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung, E-mail: k3201s@hotmail.co [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeda, Mahoto [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeguchi, Masaki [Advanced Electron Microscopy Group, National Institute for Materials Science (NIMS), Sakura 3-13, Tsukuba, 305-0047 (Japan); Bae, Dong-Sik [School of Nano and Advanced Materials Engineering, Changwon National University, Gyeongnam, 641-773 (Korea, Republic of)

    2010-04-30

    The structural evolution of nano-scale magnetic particles formed in Cu-Fe-Ni alloys on isothermal annealing at 878 K has been investigated by means of transmission electron microscopy (TEM), electron dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and field-emission scanning electron microscopy (FE-SEM). Phase decomposition of Cu-Fe-Ni occurred after an as-quenched specimen received a short anneal, and nano-scale magnetic particles were formed randomly in the Cu-rich matrix. A striking feature that two or more nano-scale particles with a cubic shape were aligned linearly along <1,0,0> directions was observed, and the trend was more pronounced at later stages of the precipitation. Large numbers of <1,0,0> linear chains of precipitates extended in three dimensions in late stages of annealing.

  20. Passive film growth on carbon steel and its nanoscale features at various passivating potentials

    International Nuclear Information System (INIS)

    Li, Yuan; Cheng, Y. Frank

    2017-01-01

    Highlights: • Imaged the topography of passivated steel at various film-forming potentials. • Characterized the nanoscale features of passive films. • Determined the composition of passive films formed at various potentials. - Abstract: In this work, the passivation and topographic sub-structure of passive films on a carbon steel in a carbonate/bicarbonate solution was characterized by electrochemical measurements, atomic force microscopy and X-ray photoelectron spectroscopy. When passivating at a potential near the active-passive transition, the film contains the mixture of Fe_3O_4, Fe_2O_3 and FeOOH, with numerous nanoscale features. As the film-forming potential shifts positively, the passive film becomes more compact and the nanoscale features disappear. When the film is formed at a passive potential where the oxygen evolution is enabled, the content of FeOOH in the film increases, resulting in an amorphous topography and reduced corrosion resistance.

  1. 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…

  2. Enhanced nanoscale friction on fluorinated graphene.

    Science.gov (United States)

    Kwon, Sangku; Ko, Jae-Hyeon; Jeon, Ki-Joon; Kim, Yong-Hyun; Park, Jeong Young

    2012-12-12

    Atomically thin graphene is an ideal model system for studying nanoscale friction due to its intrinsic two-dimensional (2D) anisotropy. Furthermore, modulating its tribological properties could be an important milestone for graphene-based micro- and nanomechanical devices. Here, we report unexpectedly enhanced nanoscale friction on chemically modified graphene and a relevant theoretical analysis associated with flexural phonons. Ultrahigh vacuum friction force microscopy measurements show that nanoscale friction on the graphene surface increases by a factor of 6 after fluorination of the surface, while the adhesion force is slightly reduced. Density functional theory calculations show that the out-of-plane bending stiffness of graphene increases up to 4-fold after fluorination. Thus, the less compliant F-graphene exhibits more friction. This indicates that the mechanics of tip-to-graphene nanoscale friction would be characteristically different from that of conventional solid-on-solid contact and would be dominated by the out-of-plane bending stiffness of the chemically modified graphene. We propose that damping via flexural phonons could be a main source for frictional energy dissipation in 2D systems such as graphene.

  3. 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...

  4. Effects of nanoscale contacts to graphene

    NARCIS (Netherlands)

    Franklin, A.D.; Han, S.-J.; Bol, A.A.; Haensch, W.

    2011-01-01

    Understanding and optimizing transport between metal contacts and graphene is one of the foremost challenges for graphene devices. In this letter, we present the first results on the effects of reducing contact dimensions to the nanoscale in single-layer graphene transistors. Using noninvasive

  5. 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...

  6. Selective nanoscale growth of lattice mismatched materials

    Science.gov (United States)

    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.

  7. Optimized structure stability and electrochemical performance of LiNi0.8Co0.15Al0.05O2 by sputtering nanoscale ZnO film

    Science.gov (United States)

    Lai, Yan-Qing; Xu, Ming; Zhang, Zhi-An; Gao, Chun-Hui; Wang, Peng; Yu, Zi-Yang

    2016-03-01

    LiNi0.8Co0.15Al0.05O2 (NCA) is one of the most promising cathode material for lithium-ion batteries (LIBs) in electric vehicles, which is successfully adopted in Tesla. However, the dissolution of the cation into the electrolyte is still a one of the major challenges (fading capacity and poor cyclability, etc.) presented in pristine NCA. Herein, a homogeneous nanoscale ZnO film is directly sputtered on the surface of NCA electrode via the magnetron sputtering (MS). This ZnO film is evidenced by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results clearly demonstrate that ZnO film is fully and uniformly covered on the NCA electrodes. After 90 cycles at 1.0C, the optimized MS-2min coated NCA electrode delivers much higher discharge capacity with 169 mAh g-1 than that of the pristine NCA electrode with 127 mAh g-1. In addition, the discharge capacity also reaches 166 mAh g-1 at 3.0C, as compared to that of 125 mAh g-1 for the pristine electrode. The improved electrochemical performance can be ascribed to the superiority of the MS ZnO film that reduce charge transfer resistance and protect the NCA electrode from cation dissolution.

  8. Vortex pinning in superconductors laterally modulated by nanoscale self-assembled arrays

    DEFF Research Database (Denmark)

    Vanacken, J.; Vinckx, W.; Moshchalkov, V.V.

    2008-01-01

    Being the exponent of the so-called "bottom-up" approach, self-assembled structures are now-a-days attracting a lot of attention in the fields of science and technology. In this work, we show that nanoscale self-assembled arrays used as templates can provide periodic modulation in superconducting...

  9. Nanoscale Cross-Point Resistive Switching Memory Comprising p-Type SnO Bilayers

    KAUST Repository

    Hota, Mrinal Kanti; Hedhili, Mohamed N.; Wang, Qingxiao; Melnikov, Vasily; Mohammed, Omar F.; Alshareef, Husam N.

    2015-01-01

    Reproducible low-voltage bipolar resistive switching is reported in bilayer structures of p-type SnO films. Specifically, a bilayer homojunction comprising SnOx (oxygen-rich) and SnOy (oxygen-deficient) in nanoscale cross-point (300 × 300 nm2

  10. Nanoscale aluminum concaves for light-trapping in organic thin-films

    DEFF Research Database (Denmark)

    Goszczak, Arkadiusz Jaroslaw; Adam, Jost; Cielecki, Pawel Piotr

    2016-01-01

    Anodic aluminum oxide (AAO) templates, fabricated from oxalic acid and phosphoric acid, lead to non-periodic nanoscale concave structures in their underlying aluminum layer, which are investigated for their field-enhancement properties by applying a thin-film polymer coating based laser ablation...

  11. Uncovering Design Principles of Intermediate Filaments, a Self-Assembling Biomaterial: Lessons in Nanoscale Materials Design

    National Research Council Canada - National Science Library

    Lee, David H

    2007-01-01

    .... Such proteins may be harnessed for military purposes (eg. protective self-healing materials or nanoscale scaffolds) if one had a better understanding of how molecular structure determines material properties. In this final progress report, we summarize our studies on these systems.

  12. Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth.

    Science.gov (United States)

    Brower, Landon J; Gentry, Lauren K; Napier, Amanda L; Anderson, Mary E

    2017-01-01

    Integration of surface-anchored metal-organic frameworks (surMOFs) within hierarchical architectures is necessary for potential sensing, electronic, optical, or separation applications. It is important to understand the fundamentals of film formation for these surMOFs in order to develop strategies for their incorporation with nanoscale control over lateral and vertical dimensions. This research identified processing parameters to control the film morphology for surMOFs of HKUST-1 fabricated by codeposition and seeded deposition. Time and temperature were investigated to observe film formation, to control film thickness, and to tune morphology. Film thickness was investigated by ellipsometry, while film structure and film roughness were characterized by atomic force microscopy. Films formed via codeposition resulted in nanocrystallites anchored to the gold substrate. A dynamic process at the interface was observed with a low density of large particulates (above 100 nm) initially forming on the substrate; and over time these particulates were slowly replaced by the prevalence of smaller crystallites (ca. 10 nm) covering the substrate at a high density. Elevated temperature was found to expedite the growth process to obtain the full range of surface morphologies with reasonable processing times. Seed crystals formed by the codeposition method were stable and nucleated growth throughout a subsequent layer-by-layer deposition process. These seed crystals templated the final film structure and tailor the features in lateral and vertical directions. Using codeposition and seeded growth, different surface morphologies with controllable nanoscale dimensions can be designed and fabricated for integration of MOF systems directly into device architectures and sensor platforms.

  13. Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth

    Directory of Open Access Journals (Sweden)

    Landon J. Brower

    2017-11-01

    Full Text Available Integration of surface-anchored metal-organic frameworks (surMOFs within hierarchical architectures is necessary for potential sensing, electronic, optical, or separation applications. It is important to understand the fundamentals of film formation for these surMOFs in order to develop strategies for their incorporation with nanoscale control over lateral and vertical dimensions. This research identified processing parameters to control the film morphology for surMOFs of HKUST-1 fabricated by codeposition and seeded deposition. Time and temperature were investigated to observe film formation, to control film thickness, and to tune morphology. Film thickness was investigated by ellipsometry, while film structure and film roughness were characterized by atomic force microscopy. Films formed via codeposition resulted in nanocrystallites anchored to the gold substrate. A dynamic process at the interface was observed with a low density of large particulates (above 100 nm initially forming on the substrate; and over time these particulates were slowly replaced by the prevalence of smaller crystallites (ca. 10 nm covering the substrate at a high density. Elevated temperature was found to expedite the growth process to obtain the full range of surface morphologies with reasonable processing times. Seed crystals formed by the codeposition method were stable and nucleated growth throughout a subsequent layer-by-layer deposition process. These seed crystals templated the final film structure and tailor the features in lateral and vertical directions. Using codeposition and seeded growth, different surface morphologies with controllable nanoscale dimensions can be designed and fabricated for integration of MOF systems directly into device architectures and sensor platforms.

  14. Resolving ultrafast exciton migration in organic solids at the nanoscale

    Science.gov (United States)

    Ginsberg, Naomi

    The migration of Frenkel excitons, tightly-bound electron-hole pairs, in photosynthesis and in organic semiconducting films is critical to the efficiency of natural and artificial light harvesting. While these materials exhibit a high degree of structural heterogeneity on the nanoscale, traditional measurements of exciton migration lengths are performed on bulk samples. Since both the characteristic length scales of structural heterogeneity and the reported bulk diffusion lengths are smaller than the optical diffraction limit, we adapt far-field super-resolution fluorescence imaging to uncover the correlations between the structural and energetic landscapes that the excitons explore. By combining the ultrafast super-resolved measurements with exciton hopping simulations we furthermore specify the nature (in addition to the extent) of exciton migration as a function of the intrinsic and ensemble chromophore energy scales that determine a spatio-energetic landscape for migration. In collaboration with: Samuel Penwell, Lucas Ginsberg, University of California, Berkeley and Rodrigo Noriega University of Utah.

  15. The development of structural x-ray crystallography

    Science.gov (United States)

    Woolfson, M. M.

    2018-03-01

    From its birth in 1912, when only the simplest structures could be solved, x-ray structural crystallography is now able to solve macromolecular structures containing many thousands of independent non-hydrogen atoms. This progress has depended on, and been driven by, great technical advances in the development of powerful synchrotron x-ray sources, advanced automated equipment for the collection and storage of large data sets and powerful computers to deal with everything from data processing to running programmes employing complex algorithms for the automatic solution of structures. The sheer number of developments in the subject over the past century makes it impossible for this review to be exhaustive, but it will describe some major developments that will enable the reader to understand how the subject has grown from its humble beginnings to what it is today.

  16. Nanoscale Metal Oxide Semiconductors for Gas Sensing

    Science.gov (United States)

    Hunter, Gary W.; Evans, Laura; Xu, Jennifer C.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Michael J.

    2011-01-01

    A report describes the fabrication and testing of nanoscale metal oxide semiconductors (MOSs) for gas and chemical sensing. This document examines the relationship between processing approaches and resulting sensor behavior. This is a core question related to a range of applications of nanotechnology and a number of different synthesis methods are discussed: thermal evaporation- condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed, providing a processing overview to developers of nanotechnology- based systems. The results of a significant amount of testing and comparison are also described. A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. The TECsynthesized single-crystal nanowires offer uniform crystal surfaces, resistance to sintering, and their synthesis may be done apart from the substrate. The TECproduced nanowire response is very low, even at the operating temperature of 200 C. In contrast, the electrospun polycrystalline nanofiber response is high, suggesting that junction potentials are superior to a continuous surface depletion layer as a transduction mechanism for chemisorption. Using a catalyst deposited upon the surface in the form of nanoparticles yields dramatic gains in sensitivity for both nanostructured, one-dimensional forms. For the nanowire materials, the response magnitude and response rate uniformly increase with increasing operating temperature. Such changes are interpreted in terms of accelerated surface diffusional processes, yielding greater access to chemisorbed oxygen species and faster dissociative chemisorption, respectively. Regardless of operating temperature, sensitivity of the nanofibers is a factor of 10 to 100 greater than that of nanowires with the same catalyst for the same test condition. In summary, nanostructure appears critical to governing the reactivity, as measured by electrical

  17. Direct optical imaging of nanoscale internal organization of polymer films

    Science.gov (United States)

    Suran, Swathi; Varma, Manoj

    2018-02-01

    Owing to its sensitivity and precise control at the nanoscale, polyelectrolytes have been immensely used to modify surfaces. Polyelectrolyte multilayers are generally water made and are easy to fabricate on any surface by the layer-by-layer (LbL) self-assembly process due to electrostatic interactions. Polyelectrolyte multilayers or PEMs can be assembled to form ultrathin membranes which can have potential applications in water filtration and desalination [1-3]. Hydration in PEMs is a consequence of both the bulk and surface phenomenon [4-7]. Bulk behavior of polymer membranes are well understood. Several techniques including reflectivity and contact angle measurements were used to measure the hydration in the bulk of polymer membranes [4, 8]. On the other hand their internal organization at the molecular level which can have a profound contribution in the transport mechanism, are not understood well. Previously, we engineered a technique, which we refer to as Bright-field Nanoscopy, which allows nanoscale optical imaging using local heterogeneities in a water-soluble germanium (Ge) thin film ( 25 nm thick) deposited on gold [8]. We use this technique to study the water transport in PEMs. It is understood that the surface charge and outer layers of the PEMs play a significant role in water transport through polymers [9-11]. This well-known `odd-even' effect arising on having different surface termination of the PEMs was optically observed with a spatial resolution unlike any other reported previously [12]. In this communication, we report that on increasing the etchant's concentration, one can control the lateral etching of the Ge film. This allowed the visualization of the nanoscale internal organization in the PEMs. Knowledge of the internal structure would allow one to engineer polymer membranes specific to applications such as drug delivering capsules, ion transport membranes and barriers etc. We also demonstrate a mathematical model involving a surface

  18. Solvent-free synthesis of nanosized hierarchical sodalite zeolite with a multi-hollow polycrystalline structure

    KAUST Repository

    Zeng, Shangjing

    2016-08-03

    A solvent-free route is developed for preparing nanoscale sodalite zeolite with a multi-hollow structure. Furthermore, the synthesis of nanosized hollow sodalite polycrystalline aggregates with a mesoporous structure and high crystallinity is investigated by adding an organosilane surfactant as a mesopore-generating agent.

  19. Nanoscale displacement sensing using microfabricated variable-inductance planar coils

    Science.gov (United States)

    Coskun, M. Bulut; Thotahewa, Kasun; Ying, York-Sing; Yuce, Mehmet; Neild, Adrian; Alan, Tuncay

    2013-09-01

    Microfabricated spiral inductors were employed for nanoscale displacement detection, suitable for use in implantable pressure sensor applications. We developed a variable inductor sensor consisting of two coaxially positioned planar coils connected in series to a measurement circuit. The devices were characterized by varying the air gap between the coils hence changing the inductance, while a Colpitts oscillator readout was used to obtain corresponding frequencies. Our approach shows significant advantages over existing methodologies combining a displacement resolution of 17 nm and low hysteresis (0.15%) in a 1 × 1 mm2 device. We show that resolution could be further improved by shrinking the device's lateral dimensions.

  20. Using Learning Trajectories for Teacher Learning to Structure Professional Development

    Science.gov (United States)

    Bargagliotti, Anna E.; Anderson, Celia Rousseau

    2017-01-01

    As a result of the increased focus on data literacy and data science across the world, there has been a large demand for professional development in statistics. However, exactly how these professional development opportunities should be structured remains an open question. The purpose of this paper is to describe the first iteration of a design…

  1. Poverty—A structural problem of developing countries

    OpenAIRE

    Wülker, Gabriele

    1981-01-01

    The contrast between industrialized and developing countries is often seen as one between two opposites: Rich countries—poor countries. But the poverty in the developing countries is by no means identical with the need for help as perceived in the industrialized societies. Poverty in the Third World is, as the following article shows, a structural problem.

  2. Students' Development of Structure Sense for the Distributive Law

    Science.gov (United States)

    Schüler-Meyer, Alexander

    2017-01-01

    After being introduced to the distributive law in meaningful contexts, students need to extend its scope of application to unfamiliar expressions. In this article, a process model for the development of structure sense is developed. Building on this model, this article reports on a design research project in which exercise tasks support students…

  3. Development of a national code of practice for structural masonry ...

    African Journals Online (AJOL)

    The problems and constraints faced by most developing countries, particularly Ghana, in developing codes of practice for structural masonry are highlighted. The steps that must be undertaken through the coordinated efforts of the National Standards Boards, Research Institutions, Universities and Professional Bodies in the ...

  4. Special Issue on the Second International Workshop on Micro- and Nano-Scale Thermal Radiation

    Science.gov (United States)

    Zhang, Zhuomin; Liu, Linhua; Zhu, Qunzhi; Mengüç, M. Pinar

    2015-06-01

    Micro- and nano-scale thermal radiation has become one of the fastest growing research areas because of advances in nanotechnology and the development of novel materials. The related research and development includes near-field radiation transfer, spectral and directional selective emitters and receivers, plasmonics, metamaterials, and novel nano-scale fabrication techniques. With the advances in these areas, important applications in energy harvesting such as solar cells and thermophotovoltaics, nanomanufacturing, biomedical sensing, thermal imaging as well as data storage with the localized heating/cooling have been pushed to higher levels.

  5. Structural and electrical characterization of ultra-thin SrTiO3 tunnel barriers grown over YBa2Cu3O7 electrodes for the development of high Tc Josephson junctions.

    Science.gov (United States)

    Félix, L Avilés; Sirena, M; Guzmán, L A Agüero; Sutter, J González; Vargas, S Pons; Steren, L B; Bernard, R; Trastoy, J; Villegas, J E; Briático, J; Bergeal, N; Lesueur, J; Faini, G

    2012-12-14

    The transport properties of ultra-thin SrTiO(3) (STO) layers grown over YBa(2)Cu(3)O(7) electrodes were studied by conductive atomic force microscopy at the nano-scale. A very good control of the barrier thickness was achieved during the deposition process. A phenomenological approach was used to obtain critical parameters regarding the structural and electrical properties of the system. The STO layers present an energy barrier of 0.9 eV and an attenuation length of 0.23 nm, indicating very good insulating properties for the development of high-quality Josephson junctions.

  6. Structural and electrical characterization of ultra-thin SrTiO3 tunnel barriers grown over YBa2Cu3O7 electrodes for the development of high Tc Josephson junctions

    International Nuclear Information System (INIS)

    Avilés Félix, L; Sirena, M; Agüero Guzmán, L A; González Sutter, J; Pons Vargas, S; Steren, L B; Bernard, R; Trastoy, J; Villegas, J E; Briático, J; Bergeal, N; Lesueur, J; Faini, G

    2012-01-01

    The transport properties of ultra-thin SrTiO 3 (STO) layers grown over YBa 2 Cu 3 O 7 electrodes were studied by conductive atomic force microscopy at the nano-scale. A very good control of the barrier thickness was achieved during the deposition process. A phenomenological approach was used to obtain critical parameters regarding the structural and electrical properties of the system. The STO layers present an energy barrier of 0.9 eV and an attenuation length of 0.23 nm, indicating very good insulating properties for the development of high-quality Josephson junctions. (paper)

  7. Development of SC structure modularization in Nuclear Power Plant

    International Nuclear Information System (INIS)

    Mun, Taeyoup

    2008-01-01

    New Focus on NPP are Rising Concerns on Global Warming, Potential energy crisis (geo-political), Improved reliability and safety of nuclear power plant, Advent of Generation 3+ NPP technology and Economical Energy Resource. New NPPs are 6 units in Korea and 23 in Asia being built, 32 units being planned in China by 2020 (150 by 2050), 10 units being planned in US by 2020 and IAEA expects $200 billions on NPP construction next 25 years (up to 30% of total world energy). □ SC(Steel Plate Concrete) structure · Steel Plate is used as a Structural Element instead of Reinforcing Bars in RC · SC structure consists of Steel Plate with Headed Studs. Connected by Tie-bars - The Primary Purpose of Tie-bars is to Stiffen and Hold Together the Plates during Construction Process - Headed Studs are Welded to the Inside of Steel Plate for composite action □ Benefits of SC Structure · Shorten Construction Duration for Re bar, Forming and Scaffolding Works · Minimize Site Labors · Improve the Construction Quality · Enable Construction Sites to be kept Clean □ SC Modularization · Fit for Modular Construction for Structural Features · Fit for Modular Construction for Structural Features · Inattentively Effective for Integrated Modules · Pre-fabrication, Pre-assembly and Modularization □ Project Overview · Project Name: Development of SC structure for Modularization in NPP · Project Type: Electric Power Industry R and D (Ministry of Knowledge Economy) · Duration: Sep. 2005 ∼ Aug. 2008 (36 Months) · Research Team and Scopes - Project Management: Korea Hydro and Nuclear Power Company (KHNP) - Development of Code and Standards for SC Structure: Korea Society of Steel Construction (KSSC) Korea Electric Power Research Institute (KEPRI) - Development of SC Structural Analysis and Design: Korea Power Engineering Company (KOPEC) - Development of Construction Techniques for SC Modularization: KHNP, Korea Institute of Nuclear Safety(KINS), KOPEC □ Performance

  8. Structural and Maturational Covariance in Early Childhood Brain Development.

    Science.gov (United States)

    Geng, Xiujuan; Li, Gang; Lu, Zhaohua; Gao, Wei; Wang, Li; Shen, Dinggang; Zhu, Hongtu; Gilmore, John H

    2017-03-01

    Brain structural covariance networks (SCNs) composed of regions with correlated variation are altered in neuropsychiatric disease and change with age. Little is known about the development of SCNs in early childhood, a period of rapid cortical growth. We investigated the development of structural and maturational covariance networks, including default, dorsal attention, primary visual and sensorimotor networks in a longitudinal population of 118 children after birth to 2 years old and compared them with intrinsic functional connectivity networks. We found that structural covariance of all networks exhibit strong correlations mostly limited to their seed regions. By Age 2, default and dorsal attention structural networks are much less distributed compared with their functional maps. The maturational covariance maps, however, revealed significant couplings in rates of change between distributed regions, which partially recapitulate their functional networks. The structural and maturational covariance of the primary visual and sensorimotor networks shows similar patterns to the corresponding functional networks. Results indicate that functional networks are in place prior to structural networks, that correlated structural patterns in adult may arise in part from coordinated cortical maturation, and that regional co-activation in functional networks may guide and refine the maturation of SCNs over childhood development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

    Science.gov (United States)

    Zecevic, Jovana; Vanbutsele, Gina; de Jong, Krijn P.; Martens, Johan A.

    2015-12-01

    The ability to control nanoscale features precisely is increasingly being exploited to develop and improve monofunctional catalysts. Striking effects might also be expected in the case of bifunctional catalysts, which are important in the hydrocracking of fossil and renewable hydrocarbon sources to provide high-quality diesel fuel. Such bifunctional hydrocracking catalysts contain metal sites and acid sites, and for more than 50 years the so-called intimacy criterion has dictated the maximum distance between the two types of site, beyond which catalytic activity decreases. A lack of synthesis and material-characterization methods with nanometre precision has long prevented in-depth exploration of the intimacy criterion, which has often been interpreted simply as ‘the closer the better’ for positioning metal and acid sites. Here we show for a bifunctional catalyst—comprising an intimate mixture of zeolite Y and alumina binder, and with platinum metal controllably deposited on either the zeolite or the binder—that closest proximity between metal and zeolite acid sites can be detrimental. Specifically, the selectivity when cracking large hydrocarbon feedstock molecules for high-quality diesel production is optimized with the catalyst that contains platinum on the binder, that is, with a nanoscale rather than closest intimacy of the metal and acid sites. Thus, cracking of the large and complex hydrocarbon molecules that are typically derived from alternative sources, such as gas-to-liquid technology, vegetable oil or algal oil, should benefit especially from bifunctional catalysts that avoid locating platinum on the zeolite (the traditionally assumed optimal location). More generally, we anticipate that the ability demonstrated here to spatially organize different active sites at the nanoscale will benefit the further development and optimization of the emerging generation of multifunctional catalysts.

  10. Recent developments in low cost stable structures for space

    International Nuclear Information System (INIS)

    Thompson, T.C.; Grastataro, C.; Smith, B.G.

    1994-01-01

    The Los Alamos National Laboratory (LANL) in partnership with Composite Optics Incorporated (COI) is advancing the development of low cost, lightweight, composite technology for use in spacecraft and stable structures. The use of advanced composites is well developed, but the application of an all-composite tracker structure has never been achieved. This paper investigates the application of composite technology to the design and fabrication of an all-composite spacecraft bus for small satellites, using technology directly applicable to central tracking in a high luminosity environment. The satellite program Fast On-Orbit Recording of Transient Events (FORTE) is the second in a series of satellites to be launched into orbit for the US Department of Energy (DOE). This paper will discuss recent developments in the area of low cost composites, used for either spacecraft or ultra stable applications in high energy physics (HEP) detectors. The use of advanced composites is a relatively new development in the area of HEP. The Superconducting Super Collider (SSC) spawned a new generation of Trackers which made extensive use of graphite fiber reinforced plastic (GFRP) composite systems. LANL has designed a structure employing new fabrication technology. This concept will lower the cost of composite structures to a point that they may now compete with conventional materials. This paper will discuss the design, analysis and proposed fabrication of a small satellite structure. Central tracking structures using advanced materials capable of operating in an adverse environment typical of that found in a high luminosity collider could use identical concepts

  11. Nanoscale Nutrient Delivery Systems for Food Applications: Improving Bioactive Dispersibility, Stability, and Bioavailability.

    Science.gov (United States)

    McClements, David Julian

    2015-07-01

    There has been a surge of interest in the development of nanoscale systems for the encapsulation, protection, and delivery of lipophilic nutrients, vitamins, and nutraceuticals. This review article highlights the challenges associated with incorporating these lipophilic bioactive components into foods, and then discusses potential nanoscale delivery systems that can be used to overcome these challenges. In particular, the desirable characteristics required for any nanoscale delivery system are presented, as well as methods of fabricating them and of characterizing them. An overview of different delivery systems is given, such as microemulsions, nanoemulsions, emulsions, microgels, and biopolymer nanoparticles, and their potential applications are discussed. Nanoscale delivery systems have considerable potential within the food industry, but they must be carefully formulated to ensure that they are safe, economically viable, and effective. Nanoscale delivery systems have numerous potential applications in the food industry for encapsulating, protecting, and releasing bioactive agents, such as nutraceuticals and vitamins. This review article highlights methods for designing, fabricating, characterizing, and utilizing edible nanoparticles from a variety of different food-grade ingredients. © 2015 Institute of Food Technologists®

  12. Development of a Computer Application to Simulate Porous Structures

    Directory of Open Access Journals (Sweden)

    S.C. Reis

    2002-09-01

    Full Text Available Geometric modeling is an important tool to evaluate structural parameters as well as to follow the application of stereological relationships. The obtention, visualization and analysis of volumetric images of the structure of materials, using computational geometric modeling, facilitates the determination of structural parameters of difficult experimental access, such as topological and morphological parameters. In this work, we developed a geometrical model implemented by computer software that simulates random pore structures. The number of nodes, number of branches (connections between nodes and the number of isolated parts, are obtained. Also, the connectivity (C is obtained from this application. Using a list of elements, nodes and branches, generated by the software, in AutoCAD® command line format, the obtained structure can be viewed and analyzed.

  13. Theoretical development of atomic structure: Past, present and future

    International Nuclear Information System (INIS)

    Tiwary, S.N.

    1994-11-01

    Theoretical development of atomic structure is briefly discussed. The role of correlation, relativity, quantum electrodynamic (QED), finite nuclear size (FNS) and parity nonconservation (PNC) in high precision theoretical investigation of properties of atomic and ionic systems is demonstrated. At present, we do not have a comprehensive and practical atomic structure theory which accounts all these physical effects on an equal footing. Suggestions are made for future directions. (author). 108 refs, 5 figs, 9 tabs

  14. Recent developments of discrete material optimization of laminated composite structures

    DEFF Research Database (Denmark)

    Lund, Erik; Sørensen, Rene

    2015-01-01

    This work will give a quick summary of recent developments of the Discrete Material Optimization approach for structural optimization of laminated composite structures. This approach can be seen as a multi-material topology optimization approach for selecting the best ply material and number...... of plies in a laminated composite structure. The conceptual combinatorial design problem is relaxed to a continuous problem such that well-established gradient based optimization techniques can be applied, and the optimization problem is solved on basis of interpolation schemes with penalization...

  15. A hard X-ray nanoprobe beamline for nanoscale microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Winarski, Robert P., E-mail: winarski@anl.gov; Holt, Martin V. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60441 (United States); Rose, Volker [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60441 (United States); Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G. Brian; McNulty, Ian [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60441 (United States); Maser, Jörg [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60441 (United States)

    2012-11-01

    The Hard X-ray Nanoprobe Beamline is a precision platform for scanning probe and full-field microscopy with 3–30 keV X-rays. A combination of high-stability X-ray optics and precision motion sensing and control enables detailed studies of the internal features of samples with resolutions approaching 30 nm. The Hard X-ray Nanoprobe Beamline (or Nanoprobe Beamline) is an X-ray microscopy facility incorporating diffraction, fluorescence and full-field imaging capabilities designed and operated by the Center for Nanoscale Materials and the Advanced Photon Source at Sector 26 of the Advanced Photon Source at Argonne National Laboratory. This facility was constructed to probe the nanoscale structure of biological, environmental and material sciences samples. The beamline provides intense focused X-rays to the Hard X-ray Nanoprobe (or Nanoprobe) which incorporates Fresnel zone plate optics and a precision laser sensing and control system. The beamline operates over X-ray energies from 3 to 30 keV, enabling studies of most elements in the periodic table, with a particular emphasis on imaging transition metals.

  16. Nanoscale strain engineering of graphene and graphene-based devices

    Institute of Scientific and Technical Information of China (English)

    N-C Yeh; C-C Hsu; M L Teague; J-Q Wang; D A Boyd; C-C Chen

    2016-01-01

    Structural distortions in nano-materials can induce dramatic changes in their electronic properties. This situation is well manifested in graphene, a two-dimensional honeycomb structure of carbon atoms with only one atomic layer thickness. In particular, strained graphene can result in both charging effects and pseudo-magnetic fields, so that controlled strain on a perfect graphene lattice can be tailored to yield desirable electronic properties. Here, we describe the theoretical foundation for strain-engineering of the electronic properties of graphene, and then provide experimental evidence for strain-induced pseudo-magnetic fields and charging effects in monolayer graphene. We further demonstrate the feasibility of nano-scale strain engineering for graphene-based devices by means of theoretical simula-tions and nano-fabrication technology.

  17. Geopressured-geothermal energy development: government incentives and institutional structures

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, D.O.; Prestwood, D.C.L.; Roberts, K.; Vanston, J.H. Jr.

    1979-01-01

    The following subjects are included: a geothermal resource overview, the evolution of the current Texas geopressured-geothermal institutional structure, project evaluation with uncertainty and the structure of incentives, the natural gas industry, the electric utility industry, potential governmental participants in resource development, industrial users of thermal energy, current government incentives bearing on geopressured-geothermal development, six profiles for utilization of the geopressured-geothermal resources in the mid-term, and probable impacts of new government incentives on mid-term resource utilization profiles. (MHR)

  18. In-situ realtime monitoring of nanoscale gold electroplating using micro-electro-mechanical systems liquid cell operating in transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Egawa, Minoru; Fujita, Hiroyuki [Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505 (Japan); Ishida, Tadashi, E-mail: ishida.t.ai@m.titech.ac.jp [Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505 (Japan); Graduate School of Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 225-8503 (Japan); Jalabert, Laurent [LIMMS/CNRS-IIS (UMI 2820), Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505 (Japan); CNRS, LAAS, 7 Avenue du Colonel Roche, F-31400 Toulouse, France and University of Toulouse, LAAS, F-31400 Toulouse (France)

    2016-01-11

    The dynamics of nanoscale electroplating between gold electrodes was investigated using a microfabricated liquid cell mounted on a scanning transmission electron microscope. The electroplating was recorded in-situ for 10 min with a spatial resolution higher than 6 nm. At the beginning of the electroplating, gold spike-like structures of about 50 nm in size grew from an electrode, connected gold nanoclusters around them, and form three dimensional nanoscale structures. We visualized the elementary process of the gold electroplating, and believe that the results lead to the deeper understanding of electroplating at the nanoscale.

  19. In-situ realtime monitoring of nanoscale gold electroplating using micro-electro-mechanical systems liquid cell operating in transmission electron microscopy

    International Nuclear Information System (INIS)

    Egawa, Minoru; Fujita, Hiroyuki; Ishida, Tadashi; Jalabert, Laurent

    2016-01-01

    The dynamics of nanoscale electroplating between gold electrodes was investigated using a microfabricated liquid cell mounted on a scanning transmission electron microscope. The electroplating was recorded in-situ for 10 min with a spatial resolution higher than 6 nm. At the beginning of the electroplating, gold spike-like structures of about 50 nm in size grew from an electrode, connected gold nanoclusters around them, and form three dimensional nanoscale structures. We visualized the elementary process of the gold electroplating, and believe that the results lead to the deeper understanding of electroplating at the nanoscale

  20. Tunable all-optical plasmonic rectifier in nanoscale metal-insulator-metal waveguides.

    Science.gov (United States)

    Xu, Yi; Wang, Xiaomeng; Deng, Haidong; Guo, Kangxian

    2014-10-15

    We propose a tunable all-optical plasmonic rectifier based on the nonlinear Fano resonance in a metal-insulator-metal plasmonic waveguide and cavities coupling system. We develop a theoretical model based on the temporal coupled-mode theory to study the device physics of the nanoscale rectifier. We further demonstrate via the finite difference time domain numerical experiment that our idea can be realized in a plasmonic system with an ultracompact size of ~120×800  nm². The tunable plasmonic rectifier could facilitate the all-optical signal processing in nanoscale.

  1. Investigation of nanoscale reinforcement into textile polymers

    Science.gov (United States)

    Khan, Mujibur Rahman

    A dual inclusion strategy for textile polymers has been investigated to increase elastic energy storage capacity of fibers used in high velocity impact applications. Commercial fibers such as Spectra and Dyneema are made from ultra high molecular weight polyethylene (UHMWPE). Dynamic elastic energy of these fibers is still low therefore limiting their wholesale application without a secondary metallic or ceramic component. The idea in this investigation is to develop methodologies so that the elastic energy of polyethylene based fibers can be increased by several folds. This would allow manufacturing of an all-fabric system for high impact applications. The dual inclusion consists of a polymer phase and a nanoscale inorganic phase to polyethylene. The polymer phase was nylon-6 and the inorganic phase was carbon nanotubes (CNTs). Nylon-6 was blended as a minor phase into UHMWPE and was chosen because of its large fracture strain -- almost one order higher than that of UHMWPE. On the other hand, CNTs with their very high strength, modulus, and aspect ratio, contributed to sharing of load and sliding of polymer interfaces as they aligned during extrusion and strain hardening processes. A solution spinning process was developed to produce UHMWPE filaments reinforced with CNTs and nylon-6. The procedure involved dispersing of CNTs into paraffin oil through sonication followed by dissolving polymers into paraffin-CNT solution using a homogenizer. The admixture was fed into a single screw extruder for melt mixing and extrusion through an orifice. The extrudate was rinsed via a hexane bath, stabilized through a heater, and then drawn into a filament winder with controlled stretching. In the next step, the as produced filaments were strain-hardened through repeated loading unloading cycles under tension. Neat and reinforced filaments were characterized through DSC (Differential Scanning Calorimetry), XRD (X-ray Diffraction), Raman Spectroscopy, SEM (Scanning Electron

  2. Nanoscale electron manipulation in metals with intense THz electric fields

    Science.gov (United States)

    Takeda, Jun; Yoshioka, Katsumasa; Minami, Yasuo; Katayama, Ikufumi

    2018-03-01

    Improved control over the electromagnetic properties of metals on a nanoscale is crucial for the development of next-generation nanoelectronics and plasmonic devices. Harnessing the terahertz (THz)-electric-field-induced nonlinearity for the motion of electrons is a promising method of manipulating the local electromagnetic properties of metals, while avoiding undesirable thermal effects and electronic transitions. In this review, we demonstrate the manipulation of electron delocalization in ultrathin gold (Au) films with nanostructures, by intense THz electric-field transients. On increasing the electric-field strength of the THz pulses, the transmittance in the THz-frequency region abruptly decreases around the percolation threshold. The observed THz-electric-field-induced nonlinearity is analysed, based on the Drude-Smith model. The results suggest that ultrafast electron delocalization occurs by electron tunnelling across the narrow insulating bridge between the Au nanostructures, without material breakdown. In order to quantitatively discuss the tunnelling process, we perform scanning tunnelling microscopy with carrier-envelope phase (CEP)-controlled single-cycle THz electric fields. By applying CEP-controlled THz electric fields to the 1 nm nanogap between a metal nanotip and graphite sample, many electrons could be coherently driven through the quantum tunnelling process, either from the nanotip to the sample or vice versa. The presented concept, namely, electron tunnelling mediated by CEP-controlled single-cycle THz electric fields, can facilitate the development of nanoscale electron manipulation, applicable to next-generation ultrafast nanoelectronics and plasmonic devices.

  3. Nanoscale microstructural characterization of a nanobainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Timokhina, I.B., E-mail: ilana.timokhina@eng.monash.edu.au [Centre for Material and Fibre Innovation, Deakin University, Victoria 3216 (Australia); Beladi, H. [Centre for Material and Fibre Innovation, Deakin University, Victoria 3216 (Australia); Xiong, X.Y. [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Adachi, Y. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Hodgson, P.D. [Centre for Material and Fibre Innovation, Deakin University, Victoria 3216 (Australia)

    2011-08-15

    A 0.79 C-1.5 Si-1.98 Mn-0.98 Cr-0.24 Mo-1.06 Al-1.58 Co (wt.%) steel was isothermally heat treated at 200 deg. C for 10 days and 350 deg. C for 1 day to form a nanoscale bainitic microstructure consisting of nanobainitic ferrite laths with high dislocation density and retained austenite films. The microstructures of the samples were characterized by transmission electron microscopy and atom probe tomography. Despite the formation of nanoscale bainite with a high volume fraction of retained austenite in both steels, the ductility of both steels was surprisingly low. It is believed that this was associated with the formation of carbon-depleted retained austenite after isothermal transformation at 200 deg. C due to the formation of high number of Fe-C clusters and particles in the bainitic ferrite laths and carbon-enriched austenite after isothermal transformation at 350 deg. C.

  4. 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....

  5. Financial structure, financial development and banking fragility: International evidence

    OpenAIRE

    Ruiz-Porras, Antonio

    2008-01-01

    We study the effects of financial structure and financial development on banking fragility. We develop our study by using fixed-effects panel-data regressions and by controlling the effects of certain banking indicators. We use individual and principal-components indicators of the activity, size and efficiency of intermediaries and markets. The indicators include data for 211 countries between 1990 and 2003. Our main findings suggest that banking stability is enhanced in market-based financia...

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Development of a remote inspection robot for high pressure structures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae C.; Kim, Jae H.; Choi, Yu R.; Moon, Soon S

    1999-10-01

    The high pressure structures in industrial plants must be periodically inspected for ensure their safety. Currently, the examination of them is manually performed by human inspectors, and there are many restrictions to examine the large containers which enclose dangerous chemicals or radioactive materials. We developed a remotely operated robot to examine these structures using recent mobile robot and computer technologies. Our robot has two magnetic caterpillars that make the robot can adhere to the structures made of steel like materials. The robot moves to the position for examination, and scans that position using ultrasonic probes equipped on it's arm, and transmits the result to the inspector according to his/her commands. Without building any auxiliary structures the robot can inspect the places where manual inspection can't reach. Therefore the robot can make shortening the inspection time as well as preventing the inspector from an accident. (author)

  11. Influence of ownership capital structure of Refinery's operation and development

    International Nuclear Information System (INIS)

    Hadzhi-Mishev, Dimitar

    1999-01-01

    Refineries are part of the energetic infrastructure of one country. Their significance is dependent on the geographic country position (whether it has sea exit or not), and on structure of primary energy spends in the country. According these facts, country's attitude to the refineries on its territory could be different. The possibility of ownership structure transformation in refineries and necessary legislation in the energetic sector of the state, needed for transformation realization are analyzed in this paper. Essential conditions for transformation fulfilling are protection 'mechanisms for domestic production in crude oil economy, manners of crude oil products price defining, and manners of excise determination and payment. As a function of these conditions, the conditions under which transformation of ownership structure in refineries is possible, as well as their influence on the operation and development of this part of energetic structure in transition country are defined in this paper. (Original)

  12. Development of a remote inspection robot for high pressure structures

    International Nuclear Information System (INIS)

    Lee, Jae C.; Kim, Jae H.; Choi, Yu R.; Moon, Soon S.

    1999-10-01

    The high pressure structures in industrial plants must be periodically inspected for ensure their safety. Currently, the examination of them is manually performed by human inspectors, and there are many restrictions to examine the large containers which enclose dangerous chemicals or radioactive materials. We developed a remotely operated robot to examine these structures using recent mobile robot and computer technologies. Our robot has two magnetic caterpillars that make the robot can adhere to the structures made of steel like materials. The robot moves to the position for examination, and scans that position using ultrasonic probes equipped on it's arm, and transmits the result to the inspector according to his/her commands. Without building any auxiliary structures the robot can inspect the places where manual inspection can't reach. Therefore the robot can make shortening the inspection time as well as preventing the inspector from an accident. (author)

  13. Thermal energy at the nanoscale

    CERN Document Server

    Fisher, Timothy S

    2014-01-01

    These lecture notes provide a detailed treatment of the thermal energy storage and transport by conduction in natural and fabricated structures. Thermal energy in two carriers, i.e. phonons and electrons -- are explored from first principles. For solid-state transport, a common Landauer framework is used for heat flow. Issues including the quantum of thermal conductance, ballistic interface resistance, and carrier scattering are elucidated. Bulk material properties, such as thermal and electrical conductivity, are derived from particle transport theories, and the effects of spatial confinement on these properties are established. Readership: Students and professionals in physics and engineering.

  14. Remote control of nanoscale devices

    Science.gov (United States)

    Högberg, Björn

    2018-01-01

    Processes that occur at the nanometer scale have a tremendous impact on our daily lives. Sophisticated evolved nanomachines operate in each of our cells; we also, as a society, increasingly rely on synthetic nanodevices for communication and computation. Scientists are still only beginning to master this scale, but, recently, DNA nanotechnology (1)—in particular, DNA origami (2)—has emerged as a powerful tool to build structures precise enough to help us do so. On page 296 of this issue, Kopperger et al. (3) show that they are now also able to control the motion of a DNA origami device from the outside by applying electric fields.

  15. Development of Mechanical Structure Design Technology for LMR

    International Nuclear Information System (INIS)

    Lee, Jae Han; Joo, Young Sang; Lee, Hyeong Yeon

    2007-03-01

    Structural integrity and design simplifications were secured on reactor core support system, upper internal structure and core catcher of KALIMER-600. The evaluation on the suitability of high temperature and seismic design of reactor structures, and the structural integrity evaluation on reactor components and high temperature pipings are performed. The interfaces between the components and ISI accessibility are checked. Lightening of reactor building by 7%, the seismic design for 0.3g seismic loads and improvement of reactor structural design concept for KALIMER-600 have been carried out. Remote inspection technique using ultrasonic wave guide sensor was acquired as a visualization method for reactor internals under opaque sodium environments. The basic guideline on high temperature structure assessment as an assessment procedure on high temperature inelastic behaviour has been completed. In high temperature creep-fatigue test, totally 500 cycles (totally 700 hold time) were carried on cylindrical test and IHTS co-axial pipe test models. The behaviors of creep-fatigue damage and creep-fatigue crack behaviour were investigated, and the DB on the structural test were established. The seismic response tests on 19-sub assembly validation test model in air and in water were carried out, and its multi-purpose characteristics and reliability on the SAC-CORE3.0 code developed for core seismic response analysis were validated

  16. Research and Development of Rapid Design Systems for Aerospace Structure

    Science.gov (United States)

    Schaeffer, Harry G.

    1999-01-01

    This report describes the results of research activities associated with the development of rapid design systems for aerospace structures in support of the Intelligent Synthesis Environment (ISE). The specific subsystems investigated were the interface between model assembly and analysis; and, the high performance NASA GPS equation solver software system in the Windows NT environment on low cost high-performance PCs.

  17. Development of strongly coupled FSI technology involving thin walled structures

    CSIR Research Space (South Africa)

    Suliman, Ridhwaan

    2011-01-01

    Full Text Available A strongly coupled finite volume-finite element fluid-structure interaction (FSI) scheme is developed. Both an edge-based finite volume and Galerkin finite element scheme are implemented and evaluated for modelling the mechanics of solids...

  18. Structure and development of the saccular sensory epithelium in ...

    African Journals Online (AJOL)

    Structure and development of the saccular sensory epithelium in relation to otolith growth in the perch Perca fluviatilis (Telostei) ... Electron microscopy indicated: 1) The apical surface of each hair cell is covered with a ciliary bundle which varies in length in different epithelial regions. Each bundle is formed from a long ...

  19. Prefabricated elements and structures: Developments, tests and experiences

    DEFF Research Database (Denmark)

    Goltermann, Per

    2014-01-01

    Danish concrete structures are often built with prefabricated elements, joined together on the site and this provides a large challenge to constantly improve and optimize the elements, the joints and the models. DTU Byg has been active in the development, testing and modelling of new elements...

  20. Horticultural marketing channels in Kenya : structure and development

    NARCIS (Netherlands)

    Dijkstra, T.

    1997-01-01

    This study analyses the structure and development of horticultural marketing channels in Kenya. It is based primarily on a farm survey among some 500 farmers in Nyandarua, Kisii and Taita Taveta Districts and a trade survey of about 750 horticultural traders in 18 different market places.

  1. Compositional effects on the development of damage structures in accelerator

    International Nuclear Information System (INIS)

    Williams, T.M.

    A study of the development of dislocation structures in charged particle irradiated austenitic alloys has shown that the effects of irradiation and materials variables may be apparent at doses of the order approximately 1 dpa. Irradiation of identical specimens to much higher doses indicates that low and high dose behaviour are closely related

  2. Development of nano-structure controlled polymer electrolyte fuel-cell membranes by high-energy heavy ion irradiation

    International Nuclear Information System (INIS)

    Yamaki, Tetsuya; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru; Kobayashi, Misaki; Nomura, Kumiko; Takagi, Shigeharu

    2008-01-01

    There is increasing interest in polymer electrolyte fuel cells (PEFCs) together with recent worldwide energy demand and environmental issues. In order to develop proton-conductive membranes for PEFCs, we have been using high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. Interestingly, the resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. According to microscopic observations, this is probably because the columnar electrolyte phase extended, with a width of tens-to-hundreds nanometers, through the membrane. Other excellent membrane properties, e.g., sufficient mechanical strength, high dimensional stability, and low gas permeability should be due to such a controlled structure. (author)

  3. Design of nanocarriers for nanoscale drug delivery to enhance cancer treatment using hybrid polymer and lipid building blocks.

    Science.gov (United States)

    Zhang, Rui Xue; Ahmed, Taksim; Li, Lily Yi; Li, Jason; Abbasi, Azhar Z; Wu, Xiao Yu

    2017-01-26

    Polymer-lipid hybrid nanoparticles (PLN) are an emerging nanocarrier platform made from building blocks of polymers and lipids. PLN integrate the advantages of biomimetic lipid-based nanoparticles (i.e. solid lipid nanoparticles and liposomes) and biocompatible polymeric nanoparticles. PLN are constructed from diverse polymers and lipids and their numerous combinations, which imparts PLN with great versatility for delivering drugs of various properties to their nanoscale targets. PLN can be classified into two types based on their hybrid nanoscopic structure and assembly methods: Type-I monolithic matrix and Type-II core-shell systems. This article reviews the history of PLN development, types of PLN, lipid and polymer candidates, fabrication methods, and unique properties of PLN. The applications of PLN in delivery of therapeutic or imaging agents alone or in combination for cancer treatment are summarized and illustrated with examples. Important considerations for the rational design of PLN for advanced nanoscale drug delivery are discussed, including selection of excipients, synthesis processes governing formulation parameters, optimization of nanoparticle properties, improvement of particle surface functionality to overcome macroscopic, microscopic and cellular biological barriers. Future directions and potential clinical translation of PLN are also suggested.

  4. Nanoscale-Barrier Formation Induced by Low-Dose Electron-Beam Exposure in Ultrathin MoS2 Transistors.

    Science.gov (United States)

    Matsunaga, Masahiro; Higuchi, Ayaka; He, Guanchen; Yamada, Tetsushi; Krüger, Peter; Ochiai, Yuichi; Gong, Yongji; Vajtai, Robert; Ajayan, Pulickel M; Bird, Jonathan P; Aoki, Nobuyuki

    2016-10-05

    Utilizing an innovative combination of scanning-probe and spectroscopic techniques, supported by first-principles calculations, we demonstrate how electron-beam exposure of field-effect transistors, implemented from ultrathin molybdenum disulfide (MoS 2 ), may cause nanoscale structural modifications that in turn significantly modify the electrical operation of these devices. Quite surprisingly, these modifications are induced by even the relatively low electron doses used in conventional electron-beam lithography, which are found to induce compressive strain in the atomically thin MoS 2 . Likely arising from sulfur-vacancy formation in the exposed regions, the strain gives rise to a local widening of the MoS 2 bandgap, an idea that is supported both by our experiment and by the results of first-principles calculations. A nanoscale potential barrier develops at the boundary between exposed and unexposed regions and may cause extrinsic variations in the resulting electrical characteristics exhibited by the transistor. The widespread use of electron-beam lithography in nanofabrication implies that the presence of such strain must be carefully considered when seeking to harness the potential of atomically thin transistors. At the same time, this work also promises the possibility of exploiting the strain as a means to achieve "bandstructure engineering" in such devices.

  5. Reducing Mg acceptor activation-energy in Al(0.83)Ga(0.17)N disorder alloy substituted by nanoscale (AlN)₅/(GaN)₁ superlattice using Mg(Ga) δ-doping: Mg local-structure effect.

    Science.gov (United States)

    Zhong, Hong-xia; Shi, Jun-jie; Zhang, Min; Jiang, Xin-he; Huang, Pu; Ding, Yi-min

    2014-10-23

    Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al(0.83)Ga(0.17)N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al(0.83)Ga(0.17)N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 10(19) cm(-3) can be obtained in (AlN)5/(GaN)1 SL by Mg(Ga) δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

  6. Reducing Mg Acceptor Activation-Energy in Al0.83Ga0.17N Disorder Alloy Substituted by Nanoscale (AlN)5/(GaN)1 Superlattice Using MgGa δ-Doping: Mg Local-Structure Effect

    Science.gov (United States)

    Zhong, Hong-Xia; Shi, Jun-Jie; Zhang, Min; Jiang, Xin-He; Huang, Pu; Ding, Yi-Min

    2014-10-01

    Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al0.83Ga0.17N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al0.83Ga0.17N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 1019 cm-3 can be obtained in (AlN)5/(GaN)1 SL by MgGa δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

  7. Development of SC structure modularization in Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Mun, Taeyoup [Korea Hydro and Nuclear Power Co., Ltd., Seoul (Korea, Republic of)

    2008-04-15

    New Focus on NPP are Rising Concerns on Global Warming, Potential energy crisis (geo-political), Improved reliability and safety of nuclear power plant, Advent of Generation 3+ NPP technology and Economical Energy Resource. New NPPs are 6 units in Korea and 23 in Asia being built, 32 units being planned in China by 2020 (150 by 2050), 10 units being planned in US by 2020 and IAEA expects $200 billions on NPP construction next 25 years (up to 30% of total world energy). {open_square} SC(Steel Plate Concrete) structure {center_dot} Steel Plate is used as a Structural Element instead of Reinforcing Bars in RC {center_dot} SC structure consists of Steel Plate with Headed Studs. Connected by Tie-bars - The Primary Purpose of Tie-bars is to Stiffen and Hold Together the Plates during Construction Process - Headed Studs are Welded to the Inside of Steel Plate for composite action {open_square} Benefits of SC Structure {center_dot} Shorten Construction Duration for Re bar, Forming and Scaffolding Works {center_dot} Minimize Site Labors {center_dot} Improve the Construction Quality {center_dot} Enable Construction Sites to be kept Clean {open_square} SC Modularization {center_dot} Fit for Modular Construction for Structural Features {center_dot} Fit for Modular Construction for Structural Features {center_dot} Inattentively Effective for Integrated Modules {center_dot} Pre-fabrication, Pre-assembly and Modularization {open_square} Project Overview {center_dot} Project Name: Development of SC structure for Modularization in NPP {center_dot} Project Type: Electric Power Industry R and D (Ministry of Knowledge Economy) {center_dot} Duration: Sep. 2005 {approx} Aug. 2008 (36 Months) {center_dot} Research Team and Scopes - Project Management: Korea Hydro and Nuclear Power Company (KHNP) - Development of Code and Standards for SC Structure: Korea Society of Steel Construction (KSSC) Korea Electric Power Research Institute (KEPRI) - Development of SC Structural Analysis and Design

  8. Development of Probabilistic Structural Analysis Integrated with Manufacturing Processes

    Science.gov (United States)

    Pai, Shantaram S.; Nagpal, Vinod K.

    2007-01-01

    An effort has been initiated to integrate manufacturing process simulations with probabilistic structural analyses in order to capture the important impacts of manufacturing uncertainties on component stress levels and life. Two physics-based manufacturing process models (one for powdered metal forging and the other for annular deformation resistance welding) have been linked to the NESSUS structural analysis code. This paper describes the methodology developed to perform this integration including several examples. Although this effort is still underway, particularly for full integration of a probabilistic analysis, the progress to date has been encouraging and a software interface that implements the methodology has been developed. The purpose of this paper is to report this preliminary development.

  9. Development of magnetostrictive active members for control of space structures

    Science.gov (United States)

    Johnson, Bruce G.; Avakian, Kevin M.; Fenn, Ralph C.; Gaffney, Monique S.; Gerver, Michael J.; Hawkey, Timothy J.; Boudreau, Donald J.

    1992-08-01

    The goal of this Phase 2 Small Business Innovative Research (SBIR) project was to determine the technical feasibility of developing magnetostrictive active members for use as truss elements in space structures. Active members control elastic vibrations of truss-based space structures and integrate the functions of truss structure element, actively controlled actuator, and sensor. The active members must control structural motion to the sub-micron level and, for many proposed space applications, work at cryogenic temperatures. Under this program both room temperature and cryogenic temperature magnetostrictive active members were designed, fabricated, and tested. The results of these performance tests indicated that room temperature magnetostrictive actuators feature higher strain, stiffness, and force capability with lower amplifier requirements than similarly sized piezoelectric or electrostrictive active members, at the cost of higher mass. Two different cryogenic temperature magnetostrictive materials were tested at liquid nitrogen temperatures, both with larger strain capability than the room temperature magnetostrictive materials. The cryogenic active member development included the design and fabrication of a cryostat that allows operation of the cryogenic active member in a space structure testbed.

  10. Nanoscale TiO2 films and their application in remediation of organic pollutants

    Science.gov (United States)

    Photocatalysis is an advanced process for treatment of air, wastewater, and drinking water, the primary advantage being its ability to mineralize many pollutants. Among several nanoscale arrangements of photocatalysts, there has been a strong push to develop them as thin films be...

  11. Comprehensive high-accuracy modeling of electromagnetic effects in complete nanoscale RF blocks: CHAMELEON RF

    NARCIS (Netherlands)

    Niehof, J.; Janssen, H.H.J.M.; Schilders, W.H.A.

    2006-01-01

    Next-generation nano-scale RFIC designs have an unprecedented complexity and performance that will inevitably lead to costly re-spins and loss of market opportunities. In order to cope with this, the aim of the European Framework 6 CHAMELEON RF project is to develop methodologies and prototype tools

  12. Interplay of Peltier and Seebeck Effects in Nanoscale Nonlocal Spin Valves

    NARCIS (Netherlands)

    Bakker, F. L.; Slachter, A.; Adam, J-P; van Wees, B. J.

    2010-01-01

    We have experimentally studied the role of thermoelectric effects in nanoscale nonlocal spin valve devices. A finite element thermoelectric model is developed to calculate the generated Seebeck voltages due to Peltier and Joule heating in the devices. By measuring the first, second, and third

  13. Nanoscale RRAM-based synaptic electronics: toward a neuromorphic computing device.

    Science.gov (United States)

    Park, Sangsu; Noh, Jinwoo; Choo, Myung-Lae; Sheri, Ahmad Muqeem; Chang, Man; Kim, Young-Bae; Kim, Chang Jung; Jeon, Moongu; Lee, Byung-Geun; Lee, Byoung Hun; Hwang, Hyunsang

    2013-09-27

    Efforts to develop scalable learning algorithms for implementation of networks of spiking neurons in silicon have been hindered by the considerable footprints of learning circuits, which grow as the number of synapses increases. Recent developments in nanotechnologies provide an extremely compact device with low-power consumption.In particular, nanoscale resistive switching devices (resistive random-access memory (RRAM)) are regarded as a promising solution for implementation of biological synapses due to their nanoscale dimensions, capacity to store multiple bits and the low energy required to operate distinct states. In this paper, we report the fabrication, modeling and implementation of nanoscale RRAM with multi-level storage capability for an electronic synapse device. In addition, we first experimentally demonstrate the learning capabilities and predictable performance by a neuromorphic circuit composed of a nanoscale 1 kbit RRAM cross-point array of synapses and complementary metal-oxide-semiconductor neuron circuits. These developments open up possibilities for the development of ubiquitous ultra-dense, ultra-low-power cognitive computers.

  14. Nanoscale RRAM-based synaptic electronics: toward a neuromorphic computing device

    International Nuclear Information System (INIS)

    Park, Sangsu; Noh, Jinwoo; Choo, Myung-lae; Sheri, Ahmad Muqeem; Jeon, Moongu; Lee, Byung-Geun; Lee, Byoung Hun; Chang, Man; Kim, Young-Bae; Kim, Chang Jung; Hwang, Hyunsang

    2013-01-01

    Efforts to develop scalable learning algorithms for implementation of networks of spiking neurons in silicon have been hindered by the considerable footprints of learning circuits, which grow as the number of synapses increases. Recent developments in nanotechnologies provide an extremely compact device with low-power consumption. In particular, nanoscale resistive switching devices (resistive random-access memory (RRAM)) are regarded as a promising solution for implementation of biological synapses due to their nanoscale dimensions, capacity to store multiple bits and the low energy required to operate distinct states. In this paper, we report the fabrication, modeling and implementation of nanoscale RRAM with multi-level storage capability for an electronic synapse device. In addition, we first experimentally demonstrate the learning capabilities and predictable performance by a neuromorphic circuit composed of a nanoscale 1 kbit RRAM cross-point array of synapses and complementary metal–oxide–semiconductor neuron circuits. These developments open up possibilities for the development of ubiquitous ultra-dense, ultra-low-power cognitive computers. (paper)

  15. Simple colorimetric assay for dehalogenation reactivity of nanoscale zero-valent iron using 4-chlorophenol

    DEFF Research Database (Denmark)

    Hwang, Yuhoon; Mines, Paul D.; Jakobsen, Mogens Havsteen

    2015-01-01

    Despite the wide application of nanoscale zero valent iron (nZVI) for the treatment of a plethora of pollutants through reductive reactions, reactivity evaluation of nZVI towards dehalogenation has not been standardized. In this light, it was desired to develop a simple colorimetric assay...

  16. In-situ Liquid Electron Microscopy Setups for Investigation of Nanoscale Electrochemistry

    DEFF Research Database (Denmark)

    Jensen, Eric; Møller-Nilsen, Rolf Erling Robberstad; Canepa, Silvia

    2014-01-01

    -situ electrochemistry and has achieved ~10 nm resolution. Such systems are important tools for developing sustainable technology and for understanding nanoscale phenomena. However, both systems suffer from interacting with theelectron beam, which is a high-voltage radiation source, and therefore initial experiments...

  17. Micro and Nano-Scale Technologies for Cell Mechanics

    Directory of Open Access Journals (Sweden)

    Mustafa Unal

    2014-10-01

    Full Text Available Cell mechanics is a multidisciplinary field that bridges cell biology, fundamental mechanics, and micro and nanotechnology, which synergize to help us better understand the intricacies and the complex nature of cells in their native environment. With recent advances in nanotechnology, microfabrication methods and micro-electro-mechanical-systems (MEMS, we are now well situated to tap into the complex micro world of cells. The field that brings biology and MEMS together is known as Biological MEMS (BioMEMS. BioMEMS take advantage of systematic design and fabrication methods to create platforms that allow us to study cells like never before. These new technologies have been rapidly advancing the study of cell mechanics. This review article provides a succinct overview of cell mechanics and comprehensively surveys micro and nano-scale technologies that have been specifically developed for and are relevant to the mechanics of cells. Here we focus on micro and nano-scale technologies, and their applications in biology and medicine, including imaging, single cell analysis, cancer cell mechanics, organ-on-a-chip systems, pathogen detection, implantable devices, neuroscience and neurophysiology. We also provide a perspective on the future directions and challenges of technologies that relate to the mechanics of cells.

  18. Intelligent Design of Nano-Scale Molecular Imaging Agents

    Directory of Open Access Journals (Sweden)

    Takeaki Ozawa

    2012-12-01

    Full Text Available Visual representation and quantification of biological processes at the cellular and subcellular levels within living subjects are gaining great interest in life science to address frontier issues in pathology and physiology. As intact living subjects do not emit any optical signature, visual representation usually exploits nano-scale imaging agents as the source of image contrast. Many imaging agents have been developed for this purpose, some of which exert nonspecific, passive, and physical interaction with a target. Current research interest in molecular imaging has mainly shifted to fabrication of smartly integrated, specific, and versatile agents that emit fluorescence or luminescence as an optical readout. These agents include luminescent quantum dots (QDs, biofunctional antibodies, and multifunctional nanoparticles. Furthermore, genetically encoded nano-imaging agents embedding fluorescent proteins or luciferases are now gaining popularity. These agents are generated by integrative design of the components, such as luciferase, flexible linker, and receptor to exert a specific on–off switching in the complex context of living subjects. In the present review, we provide an overview of the basic concepts, smart design, and practical contribution of recent nano-scale imaging agents, especially with respect to genetically encoded imaging agents.

  19. Boiling and quenching heat transfer advancement by nanoscale surface modification.

    Science.gov (United States)

    Hu, Hong; Xu, Cheng; Zhao, Yang; Ziegler, Kirk J; Chung, J N

    2017-07-21

    All power production, refrigeration, and advanced electronic systems depend on efficient heat transfer mechanisms for achieving high power density and best system efficiency. Breakthrough advancement in boiling and quenching phase-change heat transfer processes by nanoscale surface texturing can lead to higher energy transfer efficiencies, substantial energy savings, and global reduction in greenhouse gas emissions. This paper reports breakthrough advancements on both fronts of boiling and quenching. The critical heat flux (CHF) in boiling and the Leidenfrost point temperature (LPT) in quenching are the bottlenecks to the heat transfer advancements. As compared to a conventional aluminum surface, the current research reports a substantial enhancement of the CHF by 112% and an increase of the LPT by 40 K using an aluminum surface with anodized aluminum oxide (AAO) nanoporous texture finish. These heat transfer enhancements imply that the power density would increase by more than 100% and the quenching efficiency would be raised by 33%. A theory that links the nucleation potential of the surface to heat transfer rates has been developed and it successfully explains the current finding by revealing that the heat transfer modification and enhancement are mainly attributed to the superhydrophilic surface property and excessive nanoscale nucleation sites created by the nanoporous surface.

  20. Development of human brain structural networks through infancy and childhood.

    Science.gov (United States)

    Huang, Hao; Shu, Ni; Mishra, Virendra; Jeon, Tina; Chalak, Lina; Wang, Zhiyue J; Rollins, Nancy; Gong, Gaolang; Cheng, Hua; Peng, Yun; Dong, Qi; He, Yong

    2015-05-01

    During human brain development through infancy and childhood, microstructural and macrostructural changes take place to reshape the brain's structural networks and better adapt them to sophisticated functional and cognitive requirements. However, structural topological configuration of the human brain during this specific development period is not well understood. In this study, diffusion magnetic resonance image (dMRI) of 25 neonates, 13 toddlers, and 25 preadolescents were acquired to characterize network dynamics at these 3 landmark cross-sectional ages during early childhood. dMRI tractography was used to construct human brain structural networks, and the underlying topological properties were quantified by graph-theory approaches. Modular organization and small-world attributes are evident at birth with several important topological metrics increasing monotonically during development. Most significant increases of regional nodes occur in the posterior cingulate cortex, which plays a pivotal role in the functional default mode network. Positive correlations exist between nodal efficiencies and fractional anisotropy of the white matter traced from these nodes, while correlation slopes vary among the brain regions. These results reveal substantial topological reorganization of human brain structural networks through infancy and childhood, which is likely to be the outcome of both heterogeneous strengthening of the major white matter tracts and pruning of other axonal fibers. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.