WorldWideScience

Sample records for surface-controlled nanoscale materials

  1. Nanoscale materials in chemistry

    National Research Council Canada - National Science Library

    Klabunde, Kenneth J; Richards, Ryan

    2009-01-01

    ...: Disordered, Porous Nanostructures Stephanie L. Brock 209 9 Ordered Microporous and Mesoporous Materials Freddy Kleitz 243 10 Applications of Microporous and Mesoporous Materials Anirban Ghosh,...

  2. Surface Chemistry in Nanoscale Materials

    Directory of Open Access Journals (Sweden)

    Alex V. Hamza

    2009-12-01

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

  3. Surface Chemistry in Nanoscale Materials

    Science.gov (United States)

    Biener, Jürgen; Wittstock, Arne; Baumann, Theodore F.; Weissmüller, Jörg; Bäumer, Marcus; Hamza, Alex V.

    2009-01-01

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

  4. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert

    2008-11-18

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

  5. Nanoscale materials for hyperthermal theranostics

    Science.gov (United States)

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

    2015-04-01

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

  6. Nanoscale materials for hyperthermal theranostics.

    Science.gov (United States)

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

    2015-04-28

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

  7. Selective nanoscale growth of lattice mismatched materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-20

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

  8. DNA's New Avatar as Nanoscale Construction Material

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 2. DNA's New Avatar as Nanoscale Construction Material. Yamuna Krishnan. Research News Volume 13 Issue 2 February 2008 pp 195-197. Fulltext. Click here to view fulltext PDF. Permanent link:

  9. Filter casting nanoscale porous materials

    Science.gov (United States)

    Hayes, Joel Ryan; Nyce, Gregory Walker; Kuntz, Jushua David

    2013-12-10

    A method of producing nanoporous material includes the steps of providing a liquid, providing nanoparticles, producing a slurry of the liquid and the nanoparticles, removing the liquid from the slurry, and producing monolith.

  10. Computational materials science: Nanoscale plasticity

    DEFF Research Database (Denmark)

    Jacobsen, Karsten Wedel; Schiøtz, Jakob

    2002-01-01

    How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour.......How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour....

  11. Nanoscale lubrication of ionic surfaces controlled via a strong electric field.

    Science.gov (United States)

    Strelcov, Evgheni; Kumar, Rajeev; Bocharova, Vera; Sumpter, Bobby G; Tselev, Alexander; Kalinin, Sergei V

    2015-01-27

    Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip and salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. The demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems.

  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. 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. Quantum Materials at the Nanoscale - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Stephen Lance [Univ. of Illinois, Urbana, IL (United States). Dept. of Physics

    2016-01-11

    The central aim of the Quantum Materials at the Nanoscale (QMN) cluster was to understand and control collective behavior involving the interplay of spins, orbitals, and charges, which governs many scientifically interesting and technologically important phenomena in numerous complex materials. Because these phenomena involve various competing interactions, and influence properties on many different length and energy scales in complex materials, tackling this important area of study motivated a collaborative effort that combined the diverse capabilities of QMN cluster experimentalists, the essential theoretical analysis provided by QMN cluster theorists, and the outstanding facilities and staff of the FSMRL. During the funding period 2007-2014, the DOE cluster grant for the Quantum Materials at the Nanoscale (QMN) cluster supported, at various times, 15 different faculty members (14 in Physics and 1 in Materials Science and Engineering), 7 postdoctoral research associates, and 57 physics and materials science PhD students. 41 of these PhD students have since graduated and have gone on to a variety of advanced technical positions at universities, industries, and national labs: 25 obtained postdoctoral positions at universities (14), industrial labs (2 at IBM), DOE national facilities (3 at Argonne National Laboratory, 1 at Brookhaven National Lab, 1 at Lawrence Berkeley National Lab, and 1 at Sandia National Lab), and other federal facilities (2 at NIST); 13 took various industrial positions, including positions at Intel (5), Quantum Design (1), Lasque Industries (1), Amazon (1), Bloomberg (1), and J.P. Morgan (1). Thus, the QMN grant provided the essential support for training a large number of technically advanced personnel who have now entered key national facilities, industries, and institutions. Additionally, during the period 2007-2015, the QMN cluster produced 159 publications (see pages 14-23), including 23 papers published in Physical Review Letters; 16

  15. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2010-07-27

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

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

    Science.gov (United States)

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

    2006-01-01

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

  17. Nanoscale biocoordination polymers: novel materials from an old topic.

    Science.gov (United States)

    Liu, Yaling; Tang, Zhiyong

    2012-01-23

    Nature bestows many gifts upon us, among which countless biomolecules have the ability to bridge metal ions and exert the important function in biology. By taking advantage of specific interactions between metal ions and biomolecules, this article highlights a novel concept for construction of nanoscale biocoordination polymers through replacement of synthetic organic molecules with natural biomolecules as building blocks. The most recent advances are summarized and future challenges are discussed. It can be anticipated that nanoscale biocoordination polymers will become a diverse and rapidly growing class of novel materials and potentially lead to a breakthrough in biological applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Nano-Scale Positioning Design with Piezoelectric Materials

    Directory of Open Access Journals (Sweden)

    Yung Yue Chen

    2017-12-01

    Full Text Available Piezoelectric materials naturally possess high potential to deliver nano-scale positioning resolution; hence, they are adopted in a variety of engineering applications widely. Unfortunately, unacceptable positioning errors always appear because of the natural hysteresis effect of the piezoelectric materials. This natural property must be mitigated in practical applications. For solving this drawback, a nonlinear positioning design is proposed in this article. This nonlinear positioning design of piezoelectric materials is realized by the following four steps: 1. The famous Bouc–Wen model is utilized to present the input and output behaviors of piezoelectric materials; 2. System parameters of the Bouc–Wen model that describe the characteristics of piezoelectric materials are simultaneously identified with the particle swam optimization method; 3. Stability verification for the identified Bouc–Wen model; 4. A nonlinear feedback linearization control design is derived for the nano-scale positioning design of the piezoelectric material, mathematically. One important contribution of this investigation is that the positioning error between the output displacement of the controlled piezoelectric materials and the desired trajectory in nano-scale level can be proven to converge to zero asymptotically, under the effect of the hysteresis.

  19. 76 FR 35383 - Pesticides; Policies Concerning Products Containing Nanoscale Materials; Opportunity for Public...

    Science.gov (United States)

    2011-06-17

    ... materials. The Agency does not, however, intend this description to cover biological materials (e.g., DNA... nanoscale materials, including nano-titanium, nano- zinc oxide, nano-silver, nano-copper oxide, C60, and... (e.g., the active ingredient is a matrix complex comprised of the nanoscale material(s) in...

  20. 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.

  1. 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.

  2. Ion beam modification of biological materials in nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Thailand Center on Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2012-07-01

    Ion interaction with biological objects in nanoscale is a novel research area stemming from applications of low-energy ion beams in biotechnology and biomedicine. Although the ion beam applications in biotechnology and biomedicine have achieved great successes, many mechanisms remain unclear and many new applications are to be explored. We have carried out some research on exploring the mechanisms and new applications besides attaining ion beam induction of mutation breeding and gene transformation. In the studies on the mechanisms, we focused our investigations on the direct interaction in nanoscale between ions and biological living materials. Our research topics have included the low-energy ion range in DNA, low-energy ion or neutral beam bombardment effect on DNA topological form change and mutation, low-energy ion or neutral beam bombardment effect on the cell envelope and gene transformation, and molecular dynamics simulation of ultra-low-energy ion irradiation of DNA. In the exploration of new applications, we have started experiments on ion irradiation or bombardment, in the nanoscaled depth or area, of human cells for biomedical research. This paper introduces our experiments and reports interesting results.

  3. Nuclear Magnetic Resonance Study of Nanoscale Ionic Materials

    KAUST Repository

    Oommen, Joanna Mary

    2010-08-13

    Nanoscale ionic materials (NIMs) are a new class of nanomaterials that exhibit interesting properties including negligible vapor pressures and tunable physical states, among others. In this study, we analyzed the temperature-wise performance of NIMs using nuclear magnetic resonance (NMR) spectroscopy. NIMs are relatively stable over a temperature range from 300 to 383 K, rendering them usable in high temperature applications. We confirmed the presence of covalent bonds between the SiO2 core and the sulfonate group and determined relative concentrations of aromatic and aliphatic hydrocarbons. These findings serve as first hand proof-of-concept for the usefulness of NMR analyses in further studies on the diffusive properties of NIMs. © 2010 The Electrochemical Society.

  4. Resource Materials for Nanoscale Science and Technology Education

    Science.gov (United States)

    Lisensky, George

    2006-12-01

    Nanotechnology and advanced materials examples can be used to explore science and engineering concepts, exhibiting the "wow" and potential of nanotechnology, introducing prospective scientists to key ideas, and educating a citizenry capable of making well-informed technology-driven decisions. For example, material syntheses an atomic layer at a time have already revolutionized lighting and display technologies and dramatically expanded hard drive storage capacities. Resource materials include kits, models, and demonstrations that explain scanning probe microscopy, x-ray diffraction, information storage, energy and light, carbon nanotubes, and solid-state structures. An online Video Lab Manual, where movies show each step of the experiment, illustrates more than a dozen laboratory experiments involving nanoscale science and technology. Examples that are useful at a variety of levels when instructors provide the context include preparation of self-assembled monolayers, liquid crystals, colloidal gold, ferrofluid nanoparticles, nickel nanowires, solar cells, electrochromic thin films, organic light emitting diodes, and quantum dots. These resources have been developed, refined and class tested at institutions working with the Materials Research Science and Engineering Center on Nanostructured Interfaces at the University of Wisconsin-Madison (http://mrsec.wisc.edu/nano).

  5. Subsurface imaging of two-dimensional materials at the nanoscale

    Science.gov (United States)

    Dinelli, Franco; Pingue, Pasqualantonio; Kay, Nicholas D.; Kolosov, Oleg V.

    2017-02-01

    Scanning probe microscopy (SPM) represents a powerful tool that, in the past 30 years, has allowed for the investigation of material surfaces in unprecedented ways at the nanoscale level. However, SPM has shown very little capability for depth penetration, which several nanotechnology applications require. Subsurface imaging has been achieved only in a few cases, when subsurface features influence the physical properties of the surface, such as the electronic states or the heat transfer. Ultrasonic force microscopy (UFM), an adaption of the contact mode atomic force microscopy, can dynamically measure the stiffness of the elastic contact between the probing tip and the sample surface. In particular, UFM has proven highly sensitive to the near-surface elastic field in non-homogeneous samples. In this paper, we present an investigation of two-dimensional (2D) materials, namely flakes of graphite and molybdenum disulphide placed on structured polymeric substrates. We show that UFM can non-destructively distinguish suspended and supported areas and localise defects, such as buckling or delamination of adjacent monolayers, generated by residual stress. Specifically, UFM can probe small variations in the local indentation induced by the mechanical interaction between the tip and the sample. Therefore, any change in the elastic modulus within the volume perturbed by the applied load or the flexural bending of the suspended areas can be detected and imaged. These investigation capabilities are very promising in order to study the buried interfaces of nanostructured 2D materials such as in graphene-based devices.

  6. Recent advancements in nanoscale IR spectroscopy for materials science

    Science.gov (United States)

    Dillon, Eoghan; Yang, Honghua; Kjoller, Kevin; Anasys Instruments Team

    This talk will focus on the advances in measuring the chemical and optical properties of materials with nanometer scale spatial resolution. Conventional infrared spectroscopy is one of the most widely used tools for chemical analysis, but optical diffraction limits its spatial resolution to the scale of many microns. Atomic force microscopy (AFM) enjoys excellent spatial resolution, but has historically lacked the ability to perform robust chemical analysis. This presentation will discuss the advances in two techniques (1) AFM-based infrared spectroscopy (AFM-IR) and (2) scattering scanning near field optical microscopy (s-SNOM). Both of these techniques overcome the diffraction limit, providing the ability to measure and map chemical and optical properties with 10 nanometer spatial resolution. Recent advances including Tapping AFM-IR and increases in laser sweep rates have significantly improved the resolution and sensitivity of AFM-IR. As complementary techniques, AFM-IR and s-SNOM together provide an unrivaled capability to perform nanoscale chemical analysis on a diverse range of organic, inorganic, photonic and electronic materials. This talk will focus on AFM and s-SNOM applications on samples from fields including polymers, life sciences, graphene and nanoantennas.

  7. Engineering tumor cell targeting in nanoscale amyloidal materials

    Science.gov (United States)

    Unzueta, Ugutz; Seras-Franzoso, Joaquin; Virtudes Céspedes, María; Saccardo, Paolo; Cortés, Francisco; Rueda, Fabián; Garcia-Fruitós, Elena; Ferrer-Miralles, Neus; Mangues, Ramon; Vázquez, Esther; Villaverde, Antonio

    2017-01-01

    Bacterial inclusion bodies are non-toxic, mechanically stable and functional protein amyloids within the nanoscale size range that are able to naturally penetrate into mammalian cells, where they deliver the embedded protein in a functional form. The potential use of inclusion bodies in protein delivery or protein replacement therapies is strongly impaired by the absence of specificity in cell binding and penetration, thus preventing targeting. To address this issue, we have here explored whether the genetic fusion of two tumor-homing peptides, the CXCR4 ligands R9 and T22, to an inclusion body-forming green fluorescent protein (GFP), would keep the interaction potential and the functionality of the fused peptides and then confer CXCR4 specificity in cell binding and further uptake of the materials. The fusion proteins have been well produced in Escherichia coli in their full-length form, keeping the potential for fluorescence emission of the partner GFP. By using specific inhibitors of CXCR4 binding, we have demonstrated that the engineered protein particles are able to penetrate CXCR4+ cells, in a receptor-mediated way, without toxicity or visible cytopathic effects, proving the availability of the peptide ligands on the surface of inclusion bodies. Since no further modification is required upon their purification, the biological production of genetically targeted inclusion bodies opens a plethora of cost-effective possibilities in the tissue-specific intracellular transfer of functional proteins through the use of structurally and functionally tailored soft materials.

  8. Atomistic methodologies for material properties of 2D materials at the nanoscale

    Science.gov (United States)

    Zhang, Zhen

    Research on two dimensional (2D) materials, such as graphene and MoS2, now involves thousands of researchers worldwide cutting across physics, chemistry, engineering and biology. Due to the extraordinary properties of 2D materials, research extends from fundamental science to novel applications of 2D materials. From an engineering point of view, understanding the material properties of 2D materials under various conditions is crucial for tailoring the electrical and mechanical properties of 2D-material-based devices at the nanoscale. Even at the nanoscale, molecular systems typically consist of a vast number of atoms. Molecular dynamics (MD) simulations enable us to understand the properties of assemblies of molecules in terms of their structure and the microscopic interactions between them. From a continuum approach, mechanical properties and thermal properties, such as strain, stress, and heat capacity, are well defined and experimentally measurable. In MD simulations, material systems are considered to be discrete, and only interatomic potential, interatomic forces, and atom positions are directly obtainable. Besides, most of the fracture mechanics concepts, such as stress intensity factors, are not applicable since there is no singularity in MD simulations. However, energy release rate still remains to be a feasible and crucial physical quantity to characterize the fracture mechanical property of materials at the nanoscale. Therefore, equivalent definition of a physical quantity both in atomic scale and macroscopic scale is necessary in order to understand molecular and continuum scale phenomena concurrently. This work introduces atomistic simulation methodologies, based on interatomic potential and interatomic forces, as a tool to unveil the mechanical properties, thermal properties and fracture mechanical properties of 2D materials at the nanoscale. Among many 2D materials, graphene and MoS2 have attracted intense interest. Therefore, we applied our

  9. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2013-12-23

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  10. Nanoscale tissue engineering: spatial control over cell-materials interactions.

    Science.gov (United States)

    Wheeldon, Ian; Farhadi, Arash; Bick, Alexander G; Jabbari, Esmaiel; Khademhosseini, Ali

    2011-05-27

    Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness these interactions through nanoscale biomaterials engineering in order to study and direct cellular behavior. Here, we review two- and three-dimensional (2- and 3D) nanoscale tissue engineering technologies, and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffold technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D. However, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2- and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and that can control the temporal changes in the cellular microenvironment.

  11. The mechanical properties modeling of nano-scale materials by molecular dynamics

    NARCIS (Netherlands)

    Yuan, C.; Driel, W.D. van; Poelma, R.; Zhang, G.Q.

    2012-01-01

    We propose a molecular modeling strategy which is capable of mod-eling the mechanical properties on nano-scale low-dielectric (low-k) materials. Such modeling strategy has been also validated by the bulking force of carbon nano tube (CNT). This modeling framework consists of model generation method,

  12. 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.

  13. Multiresolution molecular mechanics: Surface effects in nanoscale materials

    Science.gov (United States)

    Yang, Qingcheng; To, Albert C.

    2017-05-01

    Surface effects have been observed to contribute significantly to the mechanical response of nanoscale structures. The newly proposed energy-based coarse-grained atomistic method Multiresolution Molecular Mechanics (MMM) (Yang, To (2015), [57]) is applied to capture surface effect for nanosized structures by designing a surface summation rule SRS within the framework of MMM. Combined with previously proposed bulk summation rule SRB, the MMM summation rule SRMMM is completed. SRS and SRB are consistently formed within SRMMM for general finite element shape functions. Analogous to quadrature rules in finite element method (FEM), the key idea to the good performance of SRMMM lies in that the order or distribution of energy for coarse-grained atomistic model is mathematically derived such that the number, position and weight of quadrature-type (sampling) atoms can be determined. Mathematically, the derived energy distribution of surface area is different from that of bulk region. Physically, the difference is due to the fact that surface atoms lack neighboring bonding. As such, SRS and SRB are employed for surface and bulk domains, respectively. Two- and three-dimensional numerical examples using the respective 4-node bilinear quadrilateral, 8-node quadratic quadrilateral and 8-node hexahedral meshes are employed to verify and validate the proposed approach. It is shown that MMM with SRMMM accurately captures corner, edge and surface effects with less 0.3% degrees of freedom of the original atomistic system, compared against full atomistic simulation. The effectiveness of SRMMM with respect to high order element is also demonstrated by employing the 8-node quadratic quadrilateral to solve a beam bending problem considering surface effect. In addition, the introduced sampling error with SRMMM that is analogous to numerical integration error with quadrature rule in FEM is very small.

  14. Bioinspired nanoscale materials for biomedical and energy applications.

    Science.gov (United States)

    Bhattacharya, Priyanka; Du, Dan; Lin, Yuehe

    2014-06-06

    The demand for green, affordable and environmentally sustainable materials has encouraged scientists in different fields to draw inspiration from nature in developing materials with unique properties such as miniaturization, hierarchical organization and adaptability. Together with the exceptional properties of nanomaterials, over the past century, the field of bioinspired nanomaterials has taken huge leaps. While on the one hand, the sophistication of hierarchical structures endows biological systems with multi-functionality, the synthetic control on the creation of nanomaterials enables the design of materials with specific functionalities. The aim of this review is to provide a comprehensive, up-to-date overview of the field of bioinspired nanomaterials, which we have broadly categorized into biotemplates and biomimics. We discuss the application of bioinspired nanomaterials as biotemplates in catalysis, nanomedicine, immunoassays and in energy, drawing attention to novel materials such as protein cages. Furthermore, the applications of bioinspired materials in tissue engineering and biomineralization are also discussed.

  15. Multiresolution molecular mechanics: Surface effects in nanoscale materials

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qingcheng, E-mail: qiy9@pitt.edu; To, Albert C., E-mail: albertto@pitt.edu

    2017-05-01

    Surface effects have been observed to contribute significantly to the mechanical response of nanoscale structures. The newly proposed energy-based coarse-grained atomistic method Multiresolution Molecular Mechanics (MMM) (Yang, To (2015), ) is applied to capture surface effect for nanosized structures by designing a surface summation rule SR{sup S} within the framework of MMM. Combined with previously proposed bulk summation rule SR{sup B}, the MMM summation rule SR{sup MMM} is completed. SR{sup S} and SR{sup B} are consistently formed within SR{sup MMM} for general finite element shape functions. Analogous to quadrature rules in finite element method (FEM), the key idea to the good performance of SR{sup MMM} lies in that the order or distribution of energy for coarse-grained atomistic model is mathematically derived such that the number, position and weight of quadrature-type (sampling) atoms can be determined. Mathematically, the derived energy distribution of surface area is different from that of bulk region. Physically, the difference is due to the fact that surface atoms lack neighboring bonding. As such, SR{sup S} and SR{sup B} are employed for surface and bulk domains, respectively. Two- and three-dimensional numerical examples using the respective 4-node bilinear quadrilateral, 8-node quadratic quadrilateral and 8-node hexahedral meshes are employed to verify and validate the proposed approach. It is shown that MMM with SR{sup MMM} accurately captures corner, edge and surface effects with less 0.3% degrees of freedom of the original atomistic system, compared against full atomistic simulation. The effectiveness of SR{sup MMM} with respect to high order element is also demonstrated by employing the 8-node quadratic quadrilateral to solve a beam bending problem considering surface effect. In addition, the introduced sampling error with SR{sup MMM} that is analogous to numerical integration error with quadrature rule in FEM is very small. - Highlights:

  16. Deep eutectic solvents: sustainable media for nanoscale and functional materials.

    Science.gov (United States)

    Wagle, Durgesh V; Zhao, Hua; Baker, Gary A

    2014-08-19

    Deep eutectic solvents (DESs) represent an alternative class of ionic fluids closely resembling room-temperature ionic liquids (RTILs), although, strictly speaking, they are distinguished by the fact that they also contain an organic molecular component (typically, a hydrogen bond donor like a urea, amide, acid, or polyol), frequently as the predominant constituent. Practically speaking, DESs are attractive alternatives to RTILs, sharing most of their remarkable qualities (e.g., tolerance to humidity, negligible vapor pressure, thermostability, wide electrochemical potential windows, tunability) while overcoming several limitations associated with their RTIL cousins. Particularly, DESs are typically, less expensive, more synthetically accessible (typically, from bulk commodity chemicals using solvent/waste-free processes), nontoxic, and biodegradable. In this Account, we provide an overview of DESs as designer solvents to create well-defined nanomaterials including shape-controlled nanoparticles, electrodeposited films, metal-organic frameworks, colloidal assemblies, hierarchically porous carbons, and DNA/RNA architectures. These breakthroughs illustrate how DESs can fulfill multiple roles in directing chemistry at the nanoscale: acting as supramolecular template, metal/carbon source, sacrificial agent (e.g., ammonia release from urea), and/or redox agent, all in the absence of formal stabilizing ligand (here, solvent and stabilizer are one and the same). The ability to tailor the physicochemical properties of DESs is central to controlling their interfacial behavior. The preorganized "supramolecular" nature of DESs provides a soft template to guide the formation of bimodal porous carbon networks or the evolution of electrodeposits. A number of essential parameters (viscosity, polarity, surface tension, hydrogen bonding), plus coordination with solutes/surfaces, all play significant roles in modulating species reactivity and mass transport properties governing the

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

    Science.gov (United States)

    Hong, Xia

    2016-03-01

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

  18. Monolithic silica aerogel - material design on the nano-scale

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev; Schultz, Jørgen Munthe; Kristiansen, Finn Harken

    By means of a production process in two major steps - a sol/gel process and a supercritical drying – open-cell, monolithic silica aerogel can be made. This material can have a density in the range of 30- to 300 kg/m3, corresponding to porosities between 86 and 98 %. The solid structure has...

  19. Sb-Te Phase-change Materials under Nanoscale Confinement

    Science.gov (United States)

    Ihalawela, Chandrasiri A.

    Size, speed and efficiency are the major challenges of next generation nonvolatile memory (NVM), and phase-change memory (PCM) has captured a great attention due to its promising features. The key for PCM is rapid and reversible switching between amorphous and crystalline phases with optical or electrical excitation. The structural transition is associated with significant contrast in material properties which can be utilized in optical (CD, DVD, BD) and electronic (PCRAM) memory applications. Importantly, both the functionality and the success of PCM technology significantly depend on the core material and its properties. So investigating PC materials is crucial for the development of PCM technology to realized enhanced solutions. In regards to PC materials, Sb-Te binary plays a significant role as a basis to the well-known Ge-Sb-Te system. Unlike the conventional deposition methods (sputtering, evaporation), electrochemical deposition method is used due to its multiple advantages, such as conformality, via filling capability, etc. First, the controllable synthesis of Sb-Te thin films was studied for a wide range of compositions using this novel deposition method. Secondly, the solid electrolytic nature of stoichiometric Sb2Te3 was studied with respect to precious metals. With the understanding of 2D thin film synthesis, Sb-Te 1D nanowires (18 - 220 nm) were synthesized using templated electrodeposition, where nanoporous anodic aluminum oxide (AAO) was used as a template for the growth of nanowires. In order to gain the controllability over the deposition in high aspect ratio structures, growth mechanisms of both the thin films and nanowires were investigated. Systematic understanding gained thorough previous studies helped to formulate the ultimate goal of this dissertation. In this dissertation, the main objective is to understand the size effect of PC materials on their phase transition properties. The reduction of effective memory cell size in conjunction with

  20. Final Report: Nanoscale Dynamical Heterogeneity in Complex Magnetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kevan, Stephen [Univ. of Oregon, Eugene, OR (United States)

    2016-05-27

    A magnetic object can be demagnetized by dropping it on a hard surface, but what does ‘demagnetized’ actually mean? In 1919 Heinrich Barkhausen proved the existence of magnetic domains, which are regions of uniform magnetization that are much larger than atoms but much smaller than a macroscopic object. A material is fully magnetized when domain magnetizations are aligned, while it is demagnetized when the domain magnetizations are randomly oriented and the net magnetization is zero. The heterogeneity of a demagnetized object leads to interesting questions. Magnets are unstable when their poles align, and stable when their poles anti-align, so why is the magnetized state ever stable? What do domains look like? What is the structure of a domain wall? How does the magnetized state transform to the demagnetized state? How do domains appear and disappear? What are the statistical properties of domains and how do these vary as the domain pattern evolves? Some of these questions remain the focus of intense study nearly a century after Barkhausen’s discovery. For example, just a few years ago a new kind of magnetic texture called a skyrmion was discovered. A skyrmion is a magnetic domain that is a nanometer-scale, topologically protected vortex. ‘Topologically protected’ means that skyrmions are hard to destroy and so are stable for extended periods. Skyrmions are characterized by integral quantum numbers and are observed to move with little dissipation and so could store and process information with very low power input. Our research project uses soft x-rays, which offer very high magnetic contrast, to probe magnetic heterogeneity and to measure how it evolves in time under external influences. We will condition a soft x-ray beam so that the wave fronts will be coherent, that is, they will be smooth and well-defined. When coherent soft x-ray beam interacts with a magnetic material, the magnetic heterogeneity is imprinted onto the wave fronts and projected into

  1. Nanoscale subsurface- and material-specific identification of single nanoparticles.

    Science.gov (United States)

    Nuño, Zachary; Hessler, Brandon; Ochoa, Jerry; Shon, Young-Seok; Bonney, Codi; Abate, Yohannes

    2011-10-10

    We report on high resolution subsurface and material specific differentiation of silica, Au and silica-capped Au nanoparticles using scattering-type scanning near-field optical microscopy (s-SNOM) in the visible (λ=633 nm) and mid-infrared (λ=10.7 μm) frequencies. Strong optical contrast is observed in the visible wavelength, mainly because of the dipolar plasmon resonance of the embedded Au nanoparticles which is absent in the infrared. We show that the use of small tapping amplitude improves the apparent image contrast in nanoparticles by causing increased tip-particle and reduced tip-substrate interactions. Experimental results are in excellent agreement with extended dipole model calculations modified to include the capping layer characterized by its refractive index.

  2. Nanoscale Tunable Strong Carrier Density Modulation of 2D Materials for Metamaterials and Other Tunable Optoelectronics

    Science.gov (United States)

    Peng, Cheng; Efetov, Dmitri; Shiue, Ren-Jye; Nanot, Sebastien; Hempel, Marek; Kong, Jing; Koppens, Frank; Englund, Dirk

    Strong spatial tunability of the charge carrier density at nanoscale is essential to many 2D-material-based electronic and optoelectronic applications. As an example, plasmonic metamaterials with nanoscale dimensions would make graphene plasmonics at visible and near-infrared wavelengths possible. However, existing gating techniques based on conventional dielectric gating geometries limit the spatial resolution and achievable carrier concentration, strongly restricting the available wavelength, geometry, and quality of the devices. Here, we present a novel spatially selective electrolyte gating approach that allows for in-plane spatial Fermi energy modulation of 2D materials of more than 1 eV (carrier density of n = 1014 cm-2) across a length of 2 nm. We present electrostatic simulations as well as electronic transport, photocurrent, cyclic voltammetry and optical spectroscopy measurements to characterize the performance of the gating technique applied to graphene devices. The high spatial resolution, high doping capacity, full tunability and self-aligned device geometry of the presented technique opens a new venue for nanoscale metamaterial engineering of 2D materials for complete optical absorption, nonlinear optics and sensing, among other applications.

  3. s-SNOM based microscopy and spectroscopy for nanoscale material characterization

    Science.gov (United States)

    Eisele, Max

    Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy bypassing the ubiquitous diffraction limit of light to achieve a spatial resolution below 10 nanometer. s-SNOM employs the strong confinement of light at the apex of a sharp metallic AFM tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties (dielectric function) of the sample directly below the tip and yields nanoscale resolved images simultaneous to topography. In addition to near-field microscopy the technology has been advanced to enable Fourier-transform spectroscopy (nano-FTIR) on the nanoscale using broadband radiation from the far-infrared to the visible spectral range. This presentation will summarize the latest achievements in the in the field of near-field microscopy and spectroscopy on polymers, biomaterials and 2D materials. In addition, the combination of near-field microscopy with ultrafast pump-probe experiments will be discussed opening a complete new approach solid-state physics where intriguing phenomena like surface plasmons polaritons or carrier relaxation dynamics can be observed with a combined <200fs temporal and <20nm spatial resolution.

  4. Numerical and experimental investigation for the effects of thermal loading on properties of nanoscale materials interface

    Energy Technology Data Exchange (ETDEWEB)

    Liao Ningbo [College of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035 (China); Laboratory of Materials and Micro-Structural Integrity, Jiangsu University, Zhenjiang 212013 (China); Yang Ping, E-mail: lnb55@163.com [Laboratory of Materials and Micro-Structural Integrity, Jiangsu University, Zhenjiang 212013 (China); Zhang Miao; Xue Wei [College of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035 (China)

    2010-08-20

    Research highlights: {yields} This paper proposed a atomistic model which can be used to predict the thermal and mechanical behaviors of the interface structure in composite materials and microsystem. - Abstract: For nanoscale devices and structures, interface phenomena often dominate their overall thermal behavior. Considering to the limitations of the continuum mechanics on the characterization of nanoscale, the atomistic model featuring the interface could be very important in materials design. In this paper, molecular dynamics (MD) simulations are proposed to investigate the mechanical and thermal properties at materials interface. For Al-Cu and Cr-Cu interfaces, the thermal and mechanical properties are investigated by MD simulations and the nanoindentation tests are conducted for comparison. The combined TTM (two-temperature model)-MD model is used to describe the electron-phonon scattering at interface of different metals. Both the results of MD simulations and experiments show the Young's modulus decrease after thermal cycling and the Cr-Cu interface is more sensitive to the thermal loading than the Al-Cu interface. The proposed MD model can be used to predict the thermal and mechanical behaviors of the interface structure in composite materials and microsystem.

  5. Regulatory perspective on the importance of ADME assessment of nanoscale material containing drugs.

    Science.gov (United States)

    Zolnik, Banu S; Sadrieh, Nakissa

    2009-06-21

    The promise of nanoscale material containing drug products to treat complex diseases is mounting. According to the literature, in addition to the liposomes, micelles, emulsions, there are novel drug delivery systems such as dendrimers and metal colloids at different stages of pre-clinical and clinical development. With the anticipation that more nanoscale material containing drug products will be submitted to the Food and Drug Administration (FDA) for approval in the future, FDA formed a Nanotechnology Task Force in 2006 to determine the critical regulatory issues regarding nanomaterials. As a result, all centers within the FDA are considering the development of guidance documents to address nanomaterial specific issues. It is well established in the literature that physico-chemical characterization (PCC) studies are crucial for nanomaterial containing drug products. However, this paper addresses the equally important topic of Absorption, Distribution, Metabolism and Excretion (ADME) studies for nanomaterials and provides examples of how physical properties affect biodistribution (i.e. the state of agglomeration, or aggregation, surface characteristics, stability of PEG). This paper also attempts to highlight some of the ADME study design issues related to nanomaterials such as the need for conducting biodistribution studies on each moiety of the multifunctional nanoparticles, dual labeled pharmacokinetic (PK) studies, and comparative PK studies on the free versus encapsulated drugs. In addition, this paper underlines the importance of long-term biodistribution and mass balance studies to understand the nanoparticle accumulation profile which may help to assess the safety and efficacy of the nanomaterial containing drug products. This review also lists some of the pre-clinical guidance documents that may help sponsors get started in developing data for inclusion in an initial investigational new drug application package for nanoscale material containing drug

  6. Thermal stability, swelling behavior and CO 2 absorption properties of Nanoscale Ionic Materials (NIMs)

    KAUST Repository

    Andrew Lin, Kun-Yi

    2014-11-11

    © The Royal Society of Chemistry 2015. Nanoscale Ionic Materials (NIMs) consist of a nanoscale core, a corona of charged brushes tethered on the surface of the core, and a canopy of the oppositely charged species linked to the corona. Unlike conventional polymeric nanocomposites, NIMs can display liquid-like behavior in the absence of solvents, have a negligible vapor pressure and exhibit unique solvation properties. These features enable NIMs to be a promising CO2 capture material. To optimize NIMs for CO2 capture, their structure-property relationships were examined by investigating the roles of the canopy and the core in their thermal stability, and thermally- and CO2-induced swelling behaviors. NIMs with different canopy sizes and core fractions were synthesized and their thermal stability as well as thermally- and CO2-induced swelling behaviors were determined using thermogravimetry, and ATR FT-IR and Raman spectroscopies. It was found that the ionic bonds between the canopy and the corona, as well as covalent bonds between the corona and the core significantly improved the thermal stability compared to pure polymer and polymer/nanofiller mixtures. A smaller canopy size and a larger core fraction led to a greater enhancement in thermal stability. This thermal stability enhancement was responsible for the long-term thermal stability of NIMs over 100 temperature swing cycles. Owing to their ordered structure, NIMs swelled less when heated or when they adsorbed CO2 compared to their corresponding polymers. This journal is

  7. Influence of strain on the physical properties of materials at the nanoscale

    Science.gov (United States)

    Manoharan, Mohan Prasad

    At the nanoscale, materials properties differ substantially from that at the bulk scale, opening new avenues for technological applications and basic science research. Such size effects arise from dimensional and microstructural constraints, especially when specimen size coincides with the critical fundamental length scales for various physical properties. While the state of the art practice is to investigate the size effects on 'individual' properties (mechanical or electrical or thermal and so on), the focus of this research is to explore the size effects on the 'coupling' among these domains. In particular, the effect of mechanical strain on various physical properties of materials at the nanoscale is studied. This is motivated by the hypothesis that very small elastic strain could be engineered in micro and nanoscale systems to 'tune' materials properties, which is not possible at the bulk scale using strain as a parameter. The objective of this research is to study the influence of strain on various material properties at the nanoscale, such as crystal structure, thermal and electrical conductivity, electronic bandgap and tribological properties through experimental characterization. While characterization of nanoscale materials in single domains remains the state of the art, coupled domain studies usher even stiffer challenges. This is because in addition to the difficulties in nanoscale specimen preparation, handling and properties measurement, meticulous attention has to be given to the boundary conditions for each of the domains. Another desired feature of the experimental setup is the capability for in situ high resolution microscopy so that microstructural details as well as experimental accuracy are achieved. A major contribution of this research is the development of microfabricated integrated systems to perform coupled domain characterization of small scale specimens in situ in thermal (infra-red), micro-Raman and electron microscopes. In addition

  8. Advancing Risk Analysis for Nanoscale Materials: Report from an International Workshop on the Role of Alternative Testing Strategies for Advancement: Advancing Risk Analysis for Nanoscale Materials

    Energy Technology Data Exchange (ETDEWEB)

    Shatkin, J. A. [Vireo Advisors, Boston MA USA; Ong, Kimberly J. [Vireo Advisors, Boston MA USA; Beaudrie, Christian [Compass RM, Vancouver CA USA; Clippinger, Amy J. [PETA International Science Consortium Ltd, London UK; Hendren, Christine Ogilvie [Center for the Environmental Implications of NanoTechnology, Duke University, Durham NC USA; Haber, Lynne T. [TERA, Cincinnati OH USA; Hill, Myriam [Health Canada, Ottawa Canada; Holden, Patricia [UC Santa Barbara, Bren School of Environmental Science & Management, ERI, and UC CEIN, University of California, Santa Barbara CA USA; Kennedy, Alan J. [U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg MS USA; Kim, Baram [Independent, Somerville MA USA; MacDonell, Margaret [Argonne National Laboratory, Environmental Science Division, Argonne IL USA; Powers, Christina M. [U.S. Environmental Protection Agency, Office of Air and Radiation, Office of Transportation and Air Quality, Ann Arbor MI USA; Sharma, Monita [PETA International Science Consortium Ltd, London UK; Sheremeta, Lorraine [Alberta Ingenuity Labs, Edmonton Alberta Canada; Stone, Vicki [John Muir Building Gait 1 Heriot-Watt University, Edinburgh Scotland UK; Sultan, Yasir [Environment Canada, Gatineau QC Canada; Turley, Audrey [ICF International, Durham NC USA; White, Ronald H. [RH White Consultants, Silver Spring MD USA

    2016-08-01

    The Society for Risk Analysis (SRA) has a history of bringing thought leadership to topics of emerging risk. In September 2014, the SRA Emerging Nanoscale Materials Specialty Group convened an international workshop to examine the use of alternative testing strategies (ATS) for manufactured nanomaterials (NM) from a risk analysis perspective. Experts in NM environmental health and safety, human health, ecotoxicology, regulatory compliance, risk analysis, and ATS evaluated and discussed the state of the science for in vitro and other alternatives to traditional toxicology testing for NM. Based on this review, experts recommended immediate and near-term actions that would advance ATS use in NM risk assessment. Three focal areas-human health, ecological health, and exposure considerations-shaped deliberations about information needs, priorities, and the next steps required to increase confidence in and use of ATS in NM risk assessment. The deliberations revealed that ATS are now being used for screening, and that, in the near term, ATS could be developed for use in read-across or categorization decision making within certain regulatory frameworks. Participants recognized that leadership is required from within the scientific community to address basic challenges, including standardizing materials, protocols, techniques and reporting, and designing experiments relevant to real-world conditions, as well as coordination and sharing of large-scale collaborations and data. Experts agreed that it will be critical to include experimental parameters that can support the development of adverse outcome pathways. Numerous other insightful ideas for investment in ATS emerged throughout the discussions and are further highlighted in this article.

  9. Revealing Nanoscale Passivation and Corrosion Mechanisms of Reactive Battery Materials in Gas Environments.

    Science.gov (United States)

    Li, Yuzhang; Li, Yanbin; Sun, Yongming; Butz, Benjamin; Yan, Kai; Koh, Ai Leen; Zhao, Jie; Pei, Allen; Cui, Yi

    2017-08-09

    Lithium (Li) metal is a high-capacity anode material (3860 mAh g -1 ) that can enable high-energy batteries for electric vehicles and grid-storage applications. However, Li metal is highly reactive and repeatedly consumed when exposed to liquid electrolyte (during battery operation) or the ambient environment (throughout battery manufacturing). Studying these corrosion reactions on the nanoscale is especially difficult due to the high chemical reactivity of both Li metal and its surface corrosion films. Here, we directly generate pure Li metal inside an environmental transmission electron microscope (TEM), revealing the nanoscale passivation and corrosion process of Li metal in oxygen (O 2 ), nitrogen (N 2 ), and water vapor (H 2 O). We find that while dry O 2 and N 2 (99.9999 vol %) form uniform passivation layers on Li, trace water vapor (∼1 mol %) disrupts this passivation and forms a porous film on Li metal that allows gas to penetrate and continuously react with Li. To exploit the self-passivating behavior of Li in dry conditions, we introduce a simple dry-N 2 pretreatment of Li metal to form a protective layer of Li nitride prior to battery assembly. The fast ionic conductivity and stable interface of Li nitride results in improved battery performance with dendrite-free cycling and low voltage hysteresis. Our work reveals the detailed process of Li metal passivation/corrosion and demonstrates how this mechanistic insight can guide engineering solutions for Li metal batteries.

  10. Nanoscale Engineering of Heterostructured Anode Materials for Boosting Lithium-Ion Storage.

    Science.gov (United States)

    Chen, Gen; Yan, Litao; Luo, Hongmei; Guo, Shaojun

    2016-09-01

    Rechargeable lithium-ion batteries (LIBs), as one of the most important electrochemical energy-storage devices, currently provide the dominant power source for a range of devices, including portable electronic devices and electric vehicles, due to their high energy and power densities. The interest in exploring new electrode materials for LIBs has been drastically increasing due to the surging demands for clean energy. However, the challenging issues essential to the development of electrode materials are their low lithium capacity, poor rate ability, and low cycling stability, which strongly limit their practical applications. Recent remarkable advances in material science and nanotechnology enable rational design of heterostructured nanomaterials with optimized composition and fine nanostructure, providing new opportunities for enhancing electrochemical performance. Here, the progress as to how to design new types of heterostructured anode materials for enhancing LIBs is reviewed, in the terms of capacity, rate ability, and cycling stability: i) carbon-nanomaterials-supported heterostructured anode materials; ii) conducting-polymer-coated electrode materials; iii) inorganic transition-metal compounds with core@shell structures; and iv) combined strategies to novel heterostructures. By applying different strategies, nanoscale heterostructured anode materials with reduced size, large surfaces area, enhanced electronic conductivity, structural stability, and fast electron and ion transport, are explored for boosting LIBs in terms of high capacity, long cycling lifespan, and high rate durability. Finally, the challenges and perspectives of future materials design for high-performance LIB anodes are considered. The strategies discussed here not only provide promising electrode materials for energy storage, but also offer opportunities in being extended for making a variety of novel heterostructured nanomaterials for practical renewable energy applications. © 2016

  11. Nanoscale Surface Photovoltage Mapping of 2D Materials and Heterostructures by Illuminated Kelvin Probe Force Microscopy

    KAUST Repository

    Shearer, Melinda J.

    2018-02-01

    Nanomaterials are interesting for a variety of applications, such as optoelectronics and photovoltaics. However, they often have spatial heterogeneity, i.e. composition change or physical change in the topography or structure, which can lead to varying properties that would influence their applications. New techniques must be developed to understand and correlate spatial heterogeneity with changes in electronic properties. Here we highlight the technique of surface photovoltage-Kelvin probe force microscopy (SPV-KFM), which is a modified version of non-contact atomic force microscopy capable of imaging not only the topography and surface potential, but also the surface photovoltage on the nanoscale. We demonstrate its utility in probing monolayer WSe2-MoS2 lateral heterostructures, which form an ultrathin p-n junction promising for photovoltaic and optoelectronic applications. We show surface photovoltage maps highlighting the different photoresponse of the two material regions as a result of the effective charge separation across this junction. Additionally, we study the variations between different heterostructure flakes and emphasize the importance of controlling the synthesis and transfer of these materials to obtain consistent properties and measurements.

  12. Thiol-Functionalized Gold-Nanoscale Organic Hybrid Materials-Attractive to Soft glasses

    Science.gov (United States)

    Agrawal, Akanksha; Archer, Lynden

    2014-03-01

    We report on the flow properties of self-suspended nanoparticles based on gold nanoparticles densely grafted with polyethylene glycol methyl ether thiol(PEG) chains. We studied the effect of temperature, olume fraction and polymer chain length on the transition from attractive glass to soft glassy flow behavior. Gold nanoparticles densely grafted with short PEG-thiol chains(MW 800,2kDa and 6kDa)are shown to form self-suspended systems over a range of polymer grafting densities and particle volume fractions, φ.Transmission electron and atomic force microscopy measurements reveal that the particles are uniformly dispersed. Oscillatory shear measurements performed on low φ systems show a two-step yielding behavior reflecting bond breaking and cage breaking transitions at the nanoscale; both characteristics of soft glassy materials dominated by attractive forces. With increased temperature a transition to one-step yielding and subsequently back to two-step yielding is observed. At high φ a single yielding transition and soft glassy flow behavior are observed. We employ SAXS, vibration spectroscopy, thermal analysis, and rheology to interrogate the configuration state of the tethered chains and particle-particle interactions in detail. King Abdullah Univeristy of Science and Technology (KAUST), National Science Foundation, Cornell Center for Materials Research (CCMR), Advance Photon Source at Argonne National Lab.

  13. Experimental Study of Electron and Phonon Dynamics in Nanoscale Materials by Ultrafast Laser Time-Domain Spectroscopy

    Science.gov (United States)

    Shen, Xiaohan

    With the rapid advances in the development of nanotechnology, nowadays, the sizes of elementary unit, i.e. transistor, of micro- and nanoelectronic devices are well deep into nanoscale. For the pursuit of cheaper and faster nanoscale electronic devices, the size of transistors keeps scaling down. As the miniaturization of the nanoelectronic devices, the electrical resistivity increases dramatically, resulting rapid growth in the heat generation. The heat generation and limited thermal dissipation in nanoscale materials have become a critical problem in the development of the next generation nanoelectronic devices. Copper (Cu) is widely used conducting material in nanoelectronic devices, and the electron-phonon scattering is the dominant contributor to the resistivity in Cu nanowires at room temperature. Meanwhile, phonons are the main carriers of heat in insulators, intrinsic and lightly doped semiconductors. The thermal transport is an ensemble of phonon transport, which strongly depends on the phonon frequency. In addition, the phonon transport in nanoscale materials can behave fundamentally different than in bulk materials, because of the spatial confinement. However, the size effect on electron-phonon scattering and frequency dependent phonon transport in nanoscale materials remain largely unexplored, due to the lack of suitable experimental techniques. This thesis is mainly focusing on the study of carrier dynamics and acoustic phonon transport in nanoscale materials. The weak photothermal interaction in Cu makes thermoreflectance measurement difficult, we rather measured the reflectivity change of Cu induced by absorption variation. We have developed a method to separately measure the processes of electron-electron scattering and electron-phonon scattering in epitaxial Cu films by monitoring the transient reflectivity signal using the resonant probe with particular wavelengths. The enhancement on electron-phonon scattering in epitaxial Cu films with thickness

  14. Aerosol deposition process for synthesizing optically active nano-scale materials

    Science.gov (United States)

    Chivas, Robert Douglas

    2007-12-01

    The field of optically active polycrystalline materials has two major thrusts: high-power solid-state laser hosts and scintillators. Until recently, the primary focus has been on creating high-power solid-state laser hosts for active ions. An example is Nd:Y2O3, which has the potential to outperform the Nd:YAG solid state laser. More recently, efforts have been directed to scintillating materials. Scintillators emit a visible light photon when excited by x-ray radiation. Applications of this technology range from medical imaging to bomb detection in port security. Lu2O3, YAP, and YAG are oxide scintillators. Criteria for synthesizing optimized particles for use as polycrystalline precursors exist from previous work in the field. These particles should be whole, spherical, solid, unagglomerated and sub-micrometer in size. Prior investigation into transparent oxides has established that such particles must possess cubic crystallinity, or other isometric rotational symmetry (i.e. garnet). In this work we produce particles ideal for use as precursors in polycrystalline transparent oxides. We have synthesized nano-particles for both laser hosts and scintillators, and demonstrate photoluminescence of Nd:Y 2O3. Scintillation of Eu:Lu2O 3 and Ce:YAP has been demonstrated. The primary focus of our work has been to establish and optimize an aerosol synthesis process capable of synthesizing such particles. We believe the process is transferable to any oxide material where liquid precursors exist. Extensions of this method to other materials have also been demonstrated. As an example, we have synthesized nano-scale pure germanium that possesses interesting and possibly unique optical properties. We have demonstrated photoluminescence in two energy bands with distinct lifetimes, indicating they are a result of two separate processes. Investigation of this material is in progress. Over the course of this work, we realized one of our methods preferentially created shell

  15. Nanoscale reference materials for environmental, health and safety measurements: needs, gaps and opportunities.

    Science.gov (United States)

    Stefaniak, Aleksandr B; Hackley, Vincent A; Roebben, Gert; Ehara, Kensei; Hankin, Steve; Postek, Michael T; Lynch, Iseult; Fu, Wei-En; Linsinger, Thomas P J; Thünemann, Andreas F

    2013-12-01

    The authors critically reviewed published lists of nano-objects and their physico-chemical properties deemed important for risk assessment and discussed metrological challenges associated with the development of nanoscale reference materials (RMs). Five lists were identified that contained 25 (classes of) nano-objects; only four (gold, silicon dioxide, silver, titanium dioxide) appeared on all lists. Twenty-three properties were identified for characterisation; only (specific) surface area appeared on all lists. The key themes that emerged from this review were: 1) various groups have prioritised nano-objects for development as "candidate RMs" with limited consensus; 2) a lack of harmonised terminology hinders accurate description of many nano-object properties; 3) many properties identified for characterisation are ill-defined or qualitative and hence are not metrologically traceable; 4) standardised protocols are critically needed for characterisation of nano-objects as delivered in relevant media and as administered to toxicological models; 5) the measurement processes being used to characterise a nano-object must be understood because instruments may measure a given sample in a different way; 6) appropriate RMs should be used for both accurate instrument calibration and for more general testing purposes (e.g., protocol validation); 7) there is a need to clarify that where RMs are not available, if "(representative) test materials" that lack reference or certified values may be useful for toxicology testing and 8) there is a need for consensus building within the nanotechnology and environmental, health and safety communities to prioritise RM needs and better define the required properties and (physical or chemical) forms of the candidate materials.

  16. Recent advances in energy transfer in bulk and nanoscale luminescent materials: from spectroscopy to applications.

    Science.gov (United States)

    Liu, Xiaofeng; Qiu, Jianrong

    2015-12-07

    Transfer of energy occurs endlessly in our universe by means of radiation. Compared to energy transfer (ET) in free space, in solid state materials the transfer of energy occurs in a rather confined manner, which is usually mediated by real or virtual particles, including not only photons, but also electrons, phonons, and excitons. In the present review, we discuss the recent advances in optical ET by resonance mediated with photons in solid materials as well as their nanoscale counterparts, with focus on the photoluminescence behavior pertaining to ET between optically active centers, such as rare earth (RE) ions. This review begins with a brief discussion on the classification of optical ET together with an overview of the theoretical formulations and experimental method for the examination of ET. We will then present a comprehensive discussion on the ET in practical systems in which normal photoluminescence, upconversion and quantum cutting resulted from ET involving metal ions, QDs, organic species, 2D materials and plasmonic nanostructures. Diverse ET systems are therefore simply categorized into cases of ion-ion interactions and non-ion interactions. Special attention has been paid to the progress in the manipulation of spatially confined ET in nanostructured systems including core-shell structures, as well as the ET in multiple exciton generation found in QDs and organic molecules, which behave quite similarly to resonance ET between metal ion centers. Afterwards, we will discuss the broad spectrum of applications of ET in the aforementioned systems, including solid state lighting, solar energy utilization, bio-imaging and diagnosis, and sensing. In the closing part, along with a short summary, we discuss further research focus regarding the problems and possible future directions of optical ET in solids.

  17. Nondestructive Thickness Quantification for Nanoscale Coatings on Li-Ion Battery Cathode Material.

    Science.gov (United States)

    Ouyang, Wuye; Todd, Clifford S

    2017-03-07

    Nickel manganese cobalt oxide (NMC) is a high energy capacity cathode material that attracts the interest of many research groups. Coating a protection layer on the NMC surface is one approach to improve its cycling and safety performance. However, there is no standard and consistent way to characterize the coating performance (thickness) of this protection layer, especially due to the nanoscale of primary particle and spherical morphology of the secondary particle. In this paper, a novel empirical method based on energy dispersive X-ray spectroscopy (EDX) analysis at low accelerating voltage is proposed to evaluate the protection layer thickness on the scale of tens of nanometers. The layer thickness is characterized by measuring the intensity decrease of a substrate element due to absorption by overlying coating layers. An internal standard coating (metal layer) is applied to mimic the morphology influence and improve the accuracy of thickness quantitation. For the model sample evaluation, carbon layer coatings of 1 to 10 nm thickness were successfully quantified by this method.

  18. 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

  19. Photoelectron Spectrometer and Cluster Source for the Production and Analysis of Cluster Assembled Nanoscale Materials

    National Research Council Canada - National Science Library

    Castleman, A

    2003-01-01

    ...) of nanoscale dimensions that possess selected properties. Studies thus far have yielded information on reactivity and are providing insight on methods of producing building blocks haveing the desired stoichiometry, size, and properties...

  20. Large-Scale Quantum-Mechanical Simulations of Nanoscale Devices and New Materials

    National Research Council Canada - National Science Library

    Bernholc, J; Nardelli, M. B; Lu, W; Nakhmanson, S; Meunier, V

    2004-01-01

    .... Using large scale O(N) real-space-based ab initio calculations, we carried out a theoretical study of carbon nanotube-cluster composites as prototype systems for molecular sensing at the nanoscale...

  1. Nanoscale measurement of Nernst effect in two-dimensional charge density wave material 1T-TaS2

    Science.gov (United States)

    Wu, Stephen M.; Luican-Mayer, Adina; Bhattacharya, Anand

    2017-11-01

    Advances in nanoscale material characterization on two-dimensional van der Waals layered materials primarily involve their optical and electronic properties. The thermal properties of these materials are harder to access due to the difficulty of thermal measurements at the nanoscale. In this work, we create a nanoscale magnetothermal device platform to access the basic out-of-plane magnetothermal transport properties of ultrathin van der Waals materials. Specifically, the Nernst effect in the charge density wave transition metal dichalcogenide 1T-TaS2 is examined on nano-thin flakes in a patterned device structure. It is revealed that near the commensurate charge density wave (CCDW) to nearly commensurate charge density wave (NCCDW) phase transition, the polarity of the Nernst effect changes. Since the Nernst effect is especially sensitive to changes in the Fermi surface, this suggests that large changes are occurring in the out-of-plane electronic structure of 1T-TaS2, which are otherwise unresolved in just in-plane electronic transport measurements. This may signal a coherent evolution of out-of-plane stacking in the CCDW → NCCDW transition.

  2. Nanoscale Measurement of Nernst Effect in Two-dimensional Charge Density Wave Material 1T-TaS2

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Stephen M.; Luican-Mayer, Adina; Bhattacharya, Anand

    2017-11-27

    Advances in nanoscale material characterization on two-dimensional van der Waals layered materials primarily involve their optical and electronic properties. The thermal properties of these materials are harder to access due to the difficulty of thermal measurements at the nanoscale. In this work, we create a nanoscale magnetothermal device platform to access the basic out-of-plane magnetothermal transport properties of ultrathin van der Waals materials. Specifically, the Nernst effect in the charge density wave transition metal dichalcogenide 1T-TaS2 is examined on nano-thin flakes in a patterned device structure. It is revealed that near the commensurate charge density wave (CCDW) to nearly commensurate charge density wave (NCCDW) phase transition, the polarity of the Nernst effect changes. Since the Nernst effect is especially sensitive to changes in the Fermi surface, this suggests that large changes are occurring in the out-of-plane electronic structure of 1T-TaS2, which are otherwise unresolved in just in-plane electronic transport measurements. This may signal a coherent evolution of out-of-plane stacking in the CCDW! NCCDW transition.

  3. Peptide-Directed PdAu Nanoscale Surface Segregation: Toward Controlled Bimetallic Architecture for Catalytic Materials.

    Science.gov (United States)

    Bedford, Nicholas M; Showalter, Allison R; Woehl, Taylor J; Hughes, Zak E; Lee, Sungsik; Reinhart, Benjamin; Ertem, S Piril; Coughlin, E Bryan; Ren, Yang; Walsh, Tiffany R; Bunker, Bruce A

    2016-09-27

    Bimetallic nanoparticles are of immense scientific and technological interest given the synergistic properties observed when two different metallic species are mixed at the nanoscale. This is particularly prevalent in catalysis, where bimetallic nanoparticles often exhibit improved catalytic activity and durability over their monometallic counterparts. Yet despite intense research efforts, little is understood regarding how to optimize bimetallic surface composition and structure synthetically using rational design principles. Recently, it has been demonstrated that peptide-enabled routes for nanoparticle synthesis result in materials with sequence-dependent catalytic properties, providing an opportunity for rational design through sequence manipulation. In this study, bimetallic PdAu nanoparticles are synthesized with a small set of peptides containing known Pd and Au binding motifs. The resulting nanoparticles were extensively characterized using high-resolution scanning transmission electron microscopy, X-ray absorption spectroscopy, and high-energy X-ray diffraction coupled to atomic pair distribution function analysis. Structural information obtained from synchrotron radiation methods was then used to generate model nanoparticle configurations using reverse Monte Carlo simulations, which illustrate sequence dependence in both surface structure and surface composition. Replica exchange with solute tempering molecular dynamics simulations were also used to predict the modes of peptide binding on monometallic surfaces, indicating that different sequences bind to the metal interfaces via different mechanisms. As a testbed reaction, electrocatalytic methanol oxidation experiments were performed, wherein differences in catalytic activity are clearly observed in materials with identical bimetallic composition. Taken together, this study indicates that peptides could be used to arrive at bimetallic surfaces with enhanced catalytic properties, which could be leveraged

  4. 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

  5. Nanoscale physicochemical properties of chain- and step-growth polymerized PEG hydrogels affect cell-material interactions.

    Science.gov (United States)

    Vats, Kanika; Marsh, Graham; Harding, Kristen; Zampetakis, Ioannis; Waugh, Richard E; Benoit, Danielle S W

    2017-04-01

    Poly(ethylene glycol) (PEG) hydrogels provide a versatile platform to develop cell instructive materials through incorporation of a variety of cell adhesive ligands and degradable chemistries. Synthesis of PEG gels can be accomplished via two mechanisms: chain and step growth polymerizations. The mechanism dramatically impacts hydrogel nanostructure, whereby chain polymerized hydrogels are highly heterogeneous and step growth networks exhibit more uniform structures. Underpinning these alterations in nanostructure of chain polymerized hydrogels are densely-packed hydrophobic poly(methyl methacrylate) or poly(acrylate) kinetic chains between hydrophilic PEG crosslinkers. As cell-material interactions, such as those mediated by integrins, occur at the nanoscale and affect cell behavior, it is important to understand how different modes of polymerization translate into nanoscale mechanical and hydrophobic heterogeneities of hydrogels. Therefore, chain- and step-growth polymerized PEG hydrogels with macroscopically similar macromers and compliance (for example, methacrylate-functionalized PEG (PEGDM), MW  = 10 kDa and norbornene-functionalized 4-arm PEG (PEGnorb), MW  = 10 kDa) were used to examine potential nanoscale differences in hydrogel mechanics and hydrophobicity using atomic force microscopy (AFM). It was found that chain-growth polymerized network yielded greater heterogeneities in both stiffness and hydrophobicity as compared to step-growth polymerized networks. These nanoscale heterogeneities impact cell-material interactions, particularly human mesenchymal stem cell (hMSC) adhesion and spreading, which has implications in use of these hydrogels for tissue engineering applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1112-1122, 2017. © 2017 Wiley Periodicals, Inc.

  6. Nanoscale Electrochemistry of sp(2) Carbon Materials: From Graphite and Graphene to Carbon Nanotubes.

    Science.gov (United States)

    Unwin, Patrick R; Güell, Aleix G; Zhang, Guohui

    2016-09-20

    -sphere redox processes. (ii) Demonstration of the high activity of basal plane HOPG toward other reactions, with no requirement for catalysis by step edges or defects, as exemplified by studies of proton-coupled electron transfer, redox transformations of adsorbed molecules, surface functionalization via diazonium electrochemistry, and metal electrodeposition. (iii) Rationalization of the complex interplay of different factors that determine electrochemistry at graphene, including the source (mechanical exfoliation from graphite vs chemical vapor deposition), number of graphene layers, edges, electronic structure, redox couple, and electrode history effects. (iv) New methodologies that allow nanoscale electrochemistry of 1D materials (SWNTs) to be related to their electronic characteristics (metallic vs semiconductor SWNTs), size, and quality, with high resolution imaging revealing the high activity of SWNT sidewalls and the importance of defects for some electrocatalytic reactions (e.g., the oxygen reduction reaction). The experimental approaches highlighted for carbon electrodes are generally applicable to other electrode materials and set a new framework and course for the study of electrochemical and interfacial processes.

  7. Nanoscale characterization of the thermal interface resistance of a heat-sink composite material by in situ TEM.

    Science.gov (United States)

    Kawamoto, Naoyuki; Kakefuda, Yohei; Mori, Takao; Hirose, Kenji; Mitome, Masanori; Bando, Yoshio; Golberg, Dmitri

    2015-11-20

    We developed an original method of in situ nanoscale characterization of thermal resistance utilizing a high-resolution transmission electron microscope (HRTEM). The focused electron beam of the HRTEM was used as a contact-free heat source and a piezo-movable nanothermocouple was developed as a thermal detector. This method has a high flexibility of supplying thermal-flux directions for nano/microscale thermal conductivity analysis, and is a powerful way to probe the thermal properties of complex or composite materials. Using this method we performed reproducible measurements of electron beam-induced temperature changes in pre-selected sections of a heat-sink α-Al(2)O(3)/epoxy-based resin composite. Observed linear behavior of the temperature change in a filler reveals that Fourier's law holds even at such a mesoscopic scale. In addition, we successfully determined the thermal resistance of the nanoscale interfaces between neighboring α-Al(2)O(3) fillers to be 1.16 × 10(-8) m(2)K W(-1), which is 35 times larger than that of the fillers themselves. This method that we have discovered enables evaluation of thermal resistivity of composites on the nanoscale, combined with the ultimate spatial localization and resolution sample analysis capabilities that TEM entails.

  8. DOE A9024 Final Report Functional and Nanoscale Materials Systems: Frontier Programs of Science at the Frederick Seitz Materials Research Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Jennifer A.

    2009-03-24

    The scientific programs of the FSMRL supported under the DOE A9024 Grant consisted of four interdisciplinary research clusters, as described. The clusters were led by Professors Tai Chiang (Physics), Jeffrey Moore (Chemistry), Paul Goldbart (Physics), and Steven Granick (Materials Science and Engineering). The completed work followed a dominant theme--Nanoscale Materials Systems--and emphasized studies of complex phenomena involving surfaces, interfaces, complex materials, dynamics, energetics, and structures and their transformations. A summary of our key accomplishments is provided for each cluster.

  9. Nanoscale clusters in the thermoelectric AgPbmSbTem+2 and AgnSnmSbnTem+2n materials

    Science.gov (United States)

    Lin, He; Bozin, Emil; Hoang, Khang; Mahanti, S. D.; Billinge, Simon; Quarez, Eric; Androula, John; Kanatzidis, Mercouri

    2006-03-01

    The local structure of the AgPbmSbTem+2 series of high performance thermoelectric materials has been studied using the atomic pair distribution function (PDF) method. The dimensionless thermoelectric figure of merit, ZT, of the m˜18 composition material was found to reach 1.7 at 700 kelvin, compared to the highest observed ZT of only 0.84 for PbTe at 648 kelvin in n-doped material. This is asurprisingly large enhancement in ZT for the addition of just 10%per formula-unit of silver and antimony ions. It is clearly of the greatest importance to trace the origin of the ZT enhancement. Three candidate-models were attempted for thestructure of this class of materials using either a one-phase or a two-phase modeling procedure. Combining modeling the PDF with HRTEM data we show that AgPbmSbTem+2 contains nanoscale inclusions with composition close to AgPb3SbTe5 randomly embedded in a PbTe matrix. We extended the local structural PDF study to AgnSnmSbnTem+2n, preliminary results of which suggest the presence of nanoscale inclusions in this system as well.

  10. From X-rays microscopies imaging and control to the realization of nanoscale up to mesoscale complex materials with precisely tuned correlated disorder

    Directory of Open Access Journals (Sweden)

    Nicola Poccia

    2016-01-01

    Full Text Available With the advent of novel X-ray optics technologies, it has now become possible to focalize X-rays downwards to about 50 nm. This advantage has been exploited both in physical and biological sciences in order to map the k-space characteristics onto the real space of the material. Here we will review the role X-ray microscopies have played in the field of ferroelectrics and high temperature superconductivity since the discovery of fractal self-organization of nanoscale electronic structures in the material. We will point out that the statistical analysis of weak X-ray signals due to superstructures has given unique information on the pattern and disorder displayed by the nanostructure in these materials. Now, the problem is to understand how to manipulate and control these mesoscopic nanoscale electronic and disordered systems in order to lay the basis for the development of competitive electronics. For example, continuous X-ray irradiation is a tool that can be used to control quenched disorder such as oxygen interstitials in cuprates and will therefore be reviewed. However, the artificial design of novel electronic nanoscale materials can also benefit from this information. Indeed, inspired by the nanoscale pattern observed in ferroelectric and superconducting materials with X-ray microscopies, we will discuss the design of nanoscale electronic systems with precisely tuned correlated disorder up to the mesoscale.

  11. Heat conduction in nanoscale materials: a statistical-mechanics derivation of the local heat flux.

    Science.gov (United States)

    Li, Xiantao

    2014-09-01

    We derive a coarse-grained model for heat conduction in nanoscale mechanical systems. Starting with an all-atom description, this approach yields a reduced model, in the form of conservation laws of momentum and energy. The model closure is accomplished by introducing a quasilocal thermodynamic equilibrium, followed by a linear response approximation. Of particular interest is the constitutive relation for the heat flux, which is expressed nonlocally in terms of the spatial and temporal variation of the temperature. Nanowires made of copper and silicon are presented as examples.

  12. Molecular Building Blocks for Nanotechnology From Diamondoids to Nanoscale Materials and Applications

    CERN Document Server

    Mansoori, G. Ali; Assoufid, Lahsen; Zhang, Guoping

    2007-01-01

    This book is a result of the research and educational activities of a group of outstanding scientists worldwide who have authored the chapters of this book dealing with the behavior of nanoscale building blocks. It contains a variety of subjects covering computational, dry and wet nanotechnology. The state-of-the-art subject matters presented here provide the reader with the latest developments on ongoing nanoscience and nanotechnology research from the bottom-up approach, which starts with with atoms and molecules as molecular building blocks.

  13. Enhanced electrochemical properties of LiNiO{sub 2}-based cathode materials by nanoscale manganese carbonate treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junkai; Wang, Zhixing, E-mail: zxwang.csu@hotmail.com; Guo, Huajun; Li, Xinhai

    2017-05-01

    Highlights: • Li residuals are consumed during the process of modification. • MnO{sub 2} coating layer can protect bulk material from the erosion of electrolyte. • The electrochemical performance is enhanced by the nanosacle MnCO{sub 3} treatment. • The enhancement of coating can be strengthened by the removal of lithium impurities. - Abstract: LiNiO{sub 2}-based layered oxides are of great importance as cathode materials for rechargeable batteries. In this paper, illustrating LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} as an example, the effect of nanoscale MnCO{sub 3} treatment on LiNiO{sub 2}-based materials is investigated for the first time. The structures of materials and the properties about the object surface are characterized by XRD, SEM, TEM, EDAX and XPS. The results demonstrate that a part of MnCO{sub 3} is able to react with lithium impurities to form nonstoichiometric Li{sub x}Mn{sub y}O{sub 4} and the rest of MnCO{sub 3} is converted to MnO{sub 2} coating on the surface of the material in situ. After 100 repeated cycles at 1C, the modified material exhibits a capacity retention rate of 91.2%, while the bare material only remains 84.8%. And the modified material exhibits more significantly improved cycling stability when cycling at 60 °C, maintaining 85.7% of its initial capacity at 1C after 100th cycles. The consumption of Li impurities can decelerate the decomposition of electrolyte during cycling, thus result in less resistive byproducts. Moreover, the obtained MnO{sub 2} coating layer acts as an isolating layer to suppress the drastic reaction between active material and electrolyte. This synergistic effect is responsible for the excellent properties of MnCO{sub 3}-modified material.

  14. Direct measurement of nanoscale lithium diffusion in solid battery materials using radioactive tracer of {sup 8}Li

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, H.; Jeong, S.C. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Rare Isotope Science Project (RISP), Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Watanabe, Y.X.; Hirayama, Y. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Imai, N. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Center for Nuclear Studies (CNS), Tokyo University, Wako, Saitama 351-0198 (Japan); Jung, H.S.; Miyatake, H.; Oyaizu, M. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Osa, A.; Otokawa, Y.; Matsuda, M.; Nishio, K.; Makii, H.; Sato, T.K. [Japan Atomic Energy Agency (JAEA), Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Kuwata, N.; Kawamura, J. [Institute of Multidisciplinary Research for Advance Materials, Tohoku University, Sendai 980-8577 (Japan); Ueno, H. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Kim, Y.H. [Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Kimura, S.; Mukai, M. [University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2016-06-01

    We have developed an in situ and nanoscale Li diffusion measurement method in Li battery materials using an α-emitting radioactive {sup 8}Li tracer. In this method, while implanting a low-energy (8 keV) {sup 8}Li beam, the α particles emitted at a small angle (10°) relative to the sample surface were detected as a function of time. Measurement for Li diffusion coefficients in a spinel phase LiMn{sub 2}O{sub 4} (LMO) thin film has been started, which is used as an electrode in a Li ion secondary battery. An obvious Li diffusion effect in LMO was observed at the sample temperature of 623 K, and the further measurement is underway.

  15. Designing nanoscale constructs from atomic thin sheets of graphene, boron nitride and gold nanoparticles for advanced material applications

    Science.gov (United States)

    Jasuja, Kabeer

    2011-12-01

    Nanoscale materials invite immense interest from diverse scientific disciplines as these provide access to precisely understand the physical world at their most fundamental atomic level. In concert with this aim of enhancing our understanding of the fundamental behavior at nanoscale, this dissertation presents research on three nanomaterials: Gold nanoparticles (GNPs), Graphene and ultra-thin Boron Nitride sheets (UTBNSs). The three-fold goals which drive this research are: incorporating mobility in nanoparticle based single-electron junction constructs, developing effective strategies to functionalize graphene with nano-forms of metal, and exfoliating ultrathin sheets of Boron Nitride. Gold nanoparticle based electronic constructs can achieve a new degree of operational freedom if nanoscale mobility is incorporated in their design. We achieved such a nano-electromechanical construct by incorporating elastic polymer molecules between GNPs to form 2-dimensional (2-D) molecular junctions which show a nanoscale reversible motion on applying macro scale forces. This GNP-polymer assembly works like a molecular spring opening avenues to maneuver nano components and store energy at nano-scale. Graphene is the first isolated nanomaterial that displays single-atom thickness. It exhibits quantum confinement that enables it to possess a unique combination of fascinating electronic, optical, and mechanical properties. Modifying the surface of graphene is extremely significant to enable its incorporation into applications of interest. We demonstrated the ability of chemically modified graphene sheets to act as GNP stabilizing templates in solution, and utilized this to process GNP composites of graphene. We discovered that GNPs synthesized by chemical or microwave reduction stabilize on graphene-oxide sheets to form snow-flake morphologies and bare-surfaces respectively. These hybrid nano constructs were extensively studied to understand the effect and nature of GNPs

  16. A review of patented works on the mechanical characterization of materials at micro- and nano-scale.

    Science.gov (United States)

    Alfano, Marco; Pagnotta, Leonardo; Pantano, Maria F

    2011-01-01

    In recent years, the development of cost-effective processing techniques, novel design concepts and new materials paved the way to a widespread diffusion of micro- and nano-electro-mechanical systems (NEMS/MEMS). Obviously, the reliability as well as the performance of NEMS/MEMS depend on the corresponding materials properties, which in turn should be determined using ad-hoc small samples fabricated at the relevant size-scale. For this reason, in the last decade research efforts have been devoted to the development of experimental techniques suitable for the mechanical characterization of materials at micro- and nano-scale. There are many contributions stemming from this research area, the purpose of the present work is to give an overview of the most recent patented works. The focus will be directed to selected patents on the mechanical characterization of both micro- and nanosamples, like nanotubes and nanowires. Special emphasis will be given to the methods suited for the determination of elastic properties, fracture resistance and residual stresses of materials.

  17. 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.

  18. A Strategy to Design High-Density Nanoscale Devices utilizing Vapor Deposition of Metal Halide Perovskite Materials.

    Science.gov (United States)

    Hwang, Bohee; Lee, Jang-Sik

    2017-08-01

    The demand for high memory density has increased due to increasing needs of information storage, such as big data processing and the Internet of Things. Organic-inorganic perovskite materials that show nonvolatile resistive switching memory properties have potential applications as the resistive switching layer for next-generation memory devices, but, for practical applications, these materials should be utilized in high-density data-storage devices. Here, nanoscale memory devices are fabricated by sequential vapor deposition of organolead halide perovskite (OHP) CH3 NH3 PbI3 layers on wafers perforated with 250 nm via-holes. These devices have bipolar resistive switching properties, and show low-voltage operation, fast switching speed (200 ns), good endurance, and data-retention time >10(5) s. Moreover, the use of sequential vapor deposition is extended to deposit CH3 NH3 PbI3 as the memory element in a cross-point array structure. This method to fabricate high-density memory devices could be used for memory cells that occupy large areas, and to overcome the scaling limit of existing methods; it also presents a way to use OHPs to increase memory storage capacity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ferroelectric or non-ferroelectric: Why so many materials exhibit "ferroelectricity" on the nanoscale

    Science.gov (United States)

    Vasudevan, Rama K.; Balke, Nina; Maksymovych, Peter; Jesse, Stephen; Kalinin, Sergei V.

    2017-06-01

    Ferroelectric materials have remained one of the major focal points of condensed matter physics and materials science for over 50 years. In the last 20 years, the development of voltage-modulated scanning probe microscopy techniques, exemplified by Piezoresponse force microscopy (PFM) and associated time- and voltage spectroscopies, opened a pathway to explore these materials on a single-digit nanometer level. Consequently, domain structures and walls and polarization dynamics can now be imaged in real space. More generally, PFM has allowed studying electromechanical coupling in a broad variety of materials ranging from ionics to biological systems. It can also be anticipated that the recent Nobel prize ["The Nobel Prize in Chemistry 2016," http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2016/ (Nobel Media, 2016)] in molecular electromechanical machines will result in rapid growth in interest in PFM as a method to probe their behavior on single device and device assembly levels. However, the broad introduction of PFM also resulted in a growing number of reports on the nearly ubiquitous presence of ferroelectric-like phenomena including remnant polar states and electromechanical hysteresis loops in materials which are non-ferroelectric in the bulk or in cases where size effects are expected to suppress ferroelectricity. While in certain cases plausible physical mechanisms can be suggested, there is remarkable similarity in observed behaviors, irrespective of the materials system. In this review, we summarize the basic principles of PFM, briefly discuss the features of ferroelectric surfaces salient to PFM imaging and spectroscopy, and summarize existing reports on ferroelectric-like responses in non-classical ferroelectric materials. We further discuss possible mechanisms behind observed behaviors and possible experimental strategies for their identification.

  20. Linking nanoscale mechanical behavior to bulk physical properties and phenomena of energetic materials

    Science.gov (United States)

    Taw, Matthew R.

    The hardness and reduced modulus of aspirin, RDX, HMX, TATB, FOX-7, ADAAF, and TNT/CL-20 were experimentally measured with nanoindentation. These values are reported for the first time using as-received micron sized crystals of energetic materials with no additional mechanical processing. The results for TATB, ADAAF, and TNT/CL-20 are the first of their kind, while comparisons to previous nanoindentation studies on large, carefully grown single crystals of the other energetic materials show that mechanical properties of the larger crystals are comparable to crystals in the condition they are practically used. Measurements on aspirin demonstrate the variation that can occur between nanoindentation indents based on the orientation of a Berkovich tip relative to the surface of the sample. The Hertzian elastic contact model was used to analyze the materials initial yield, or pop-in, behavior. The length, energy, indentation load, and shear stress at initial yielding were used to characterize each material. For the energetic materials the length and energy of the yield excursions were compared to the drop weight sensitivity. This comparison revealed a general trend that more impact sensitive materials have longer, more severe pop-in excursions. Hot spot initiation mechanisms involving crystal defects such as void collapses and dislocation pile-up followed by avalanche are supported by these trends. While this only takes one aspect of impact sensitivity into consideration, if this trend is observed in a larger range of energetics these methods could possibly be used to great advantage in the early stages of new explosives synthesis to obtain an estimation of drop weight sensitivity.

  1. Computational Methods for Nanoscale X-ray Computed Tomography Image Analysis of Fuel Cell and Battery Materials

    Science.gov (United States)

    Kumar, Arjun S.

    Over the last fifteen years, there has been a rapid growth in the use of high resolution X-ray computed tomography (HRXCT) imaging in material science applications. We use it at nanoscale resolutions up to 50 nm (nano-CT) for key research problems in large scale operation of polymer electrolyte membrane fuel cells (PEMFC) and lithium-ion (Li-ion) batteries in automotive applications. PEMFC are clean energy sources that electrochemically react with hydrogen gas to produce water and electricity. To reduce their costs, capturing their electrode nanostructure has become significant in modeling and optimizing their performance. For Li-ion batteries, a key challenge in increasing their scope for the automotive industry is Li metal dendrite growth. Li dendrites are structures of lithium with 100 nm features of interest that can grow chaotically within a battery and eventually lead to a short-circuit. HRXCT imaging is an effective diagnostics tool for such applications as it is a non-destructive method of capturing the 3D internal X-ray absorption coefficient of materials from a large series of 2D X-ray projections. Despite a recent push to use HRXCT for quantitative information on material samples, there is a relative dearth of computational tools in nano-CT image processing and analysis. Hence, we focus on developing computational methods for nano-CT image analysis of fuel cell and battery materials as required by the limitations in material samples and the imaging environment. The first problem we address is the segmentation of nano-CT Zernike phase contrast images. Nano-CT instruments are equipped with Zernike phase contrast optics to distinguish materials with a low difference in X-ray absorption coefficient by phase shifting the X-ray wave that is not diffracted by the sample. However, it creates image artifacts that hinder the use of traditional image segmentation techniques. To restore such images, we setup an inverse problem by modeling the X-ray phase contrast

  2. Synthesis of Nanoscale Lithium-Ion Battery Cathode Materials Using a Porous Polymer Precursor Method

    KAUST Repository

    Deshazer, H.D.

    2011-01-01

    Fine particles of metal oxides with carefully controlled compositions can be easily prepared by the thermal decomposition of porous polymers, such as cellulose, into which solutions containing salts of the desired cations have been dissolved. This is a simple and versatile method that can be used to produce a wide variety of materials with a range of particle sizes and carefully controlled chemical compositions. Examples of the use of this method to produce fine particles of LiCoO2 and Li(NiMnCo)1/3O2, which are used in the positive electrodes of lithium-ion batteries, are shown. Experiments have demonstrated that materials made using this method can have electrochemical properties comparable to those typically produced by more elaborate procedures. © 2011 The Electrochemical Society.

  3. Advanced Nanoscale Characterization of Cement Based Materials Using X-Ray Synchrotron Radiation: A Review

    KAUST Repository

    Chae, Sejung R.

    2013-05-22

    We report various synchrotron radiation laboratory based techniques used to characterize cement based materials in nanometer scale. High resolution X-ray transmission imaging combined with a rotational axis allows for rendering of samples in three dimensions revealing volumetric details. Scanning transmission X-ray microscope combines high spatial resolution imaging with high spectral resolution of the incident beam to reveal X-ray absorption near edge structure variations in the material nanostructure. Microdiffraction scans the surface of a sample to map its high order reflection or crystallographic variations with a micron-sized incident beam. High pressure X-ray diffraction measures compressibility of pure phase materials. Unique results of studies using the above tools are discussed-a study of pores, connectivity, and morphology of a 2,000 year old concrete using nanotomography; detection of localized and varying silicate chain depolymerization in Al-substituted tobermorite, and quantification of monosulfate distribution in tricalcium aluminate hydration using scanning transmission X-ray microscopy; detection and mapping of hydration products in high volume fly ash paste using microdiffraction; and determination of mechanical properties of various AFm phases using high pressure X-ray diffraction. © 2013 The Author(s).

  4. In Vitro Evaluation of Nanoscale Hydroxyapatite-Based Bone Reconstructive Materials with Antimicrobial Properties.

    Science.gov (United States)

    Ajduković, Zorica R; Mihajilov-Krstev, Tatjana M; Ignjatović, Nenad L; Stojanović, Zoran; Mladenović-Antić, Snezana B; Kocić, Branislava D; Najman, Stevo; Petrović, Nenad D; Uskoković, Dragan P

    2016-02-01

    In the field of oral implantology the loss of bone tissue prevents adequate patient care, and calls for the use of synthetic biomaterials with properties that resemble natural bone. Special attention is paid to the risk of infection after the implantation of these materials. Studies have suggested that some nanocontructs containing metal ions have antimicrobial properties. The aim of this study was to examine the antimicrobial and hemolytic activity of cobalt-substituted hydroxyapatite nanoparticles, compared to hydroxyapatite and hydroxyapatite/poly-lactide-co-glycolide. The antibacterial effects of these powders were tested against two pathogenic bacterial strains: Escherichia coi (ATCC 25922) and Staphylococcus aureus (ATCC 25923), using the disc diffusion method and the quantitative antimicrobial test in a liquid medium. The quantitative antimicrobial test showed that all of the tested biomaterials have some antibacterial properties. The effects of both tests were more prominent in case of S. aureus than in E coli. A higher percentage of cobalt in the crystal structure of cobalt-substituted hydroxyapatite nanoparticles led to an increased antimicrobial activity. All of the presented biomaterial samples were found to be non-hemolytic. Having in mind that the tested of cobalt-substituted hydroxyapatite (Ca/Co-HAp) material in given concentrations shows good hemocompatibility and antimicrobial effects, along with its previously studied biological properties, the conclusion can be reached that it is a potential candidate that could substitute calcium hydroxyapatite as the material of choice for use in bone tissue engineering and clinical practices in orthopedic, oral and maxillofacial surgery.

  5. Rotaxanes and Photovoltaic Materials Based on Pi-Conjugated Donors and Acceptors: Toward Energy Transduction on the Nanoscale

    Science.gov (United States)

    Bruns, Carson J.

    The flow of energy between its various forms is central to our understanding of virtually all natural phenomena, from the origins and fate of the universe to the mechanisms that underpin Life. Therefore, a deeper fundamental understanding of how to manage energy processes at the molecular scale will open new doors in science and technology. This dissertation describes organic molecules and materials that are capable of transducing various forms of energy on the nanoscale, namely, a class of mechanically interlocked molecules known as rotaxanes for electrochemical-to-mechanical energy transduction (Part I), and a class of thin films known as organic photovoltaics (OPVs) for solar-to-electric energy transduction (Part II). These materials are all based on conjugated molecules with a capacity to donate or accept pi-electrons. A contemporary challenge in molecular nanotechnology is the development of artificial molecular machines (AMMs) that mimic the ability of motor proteins (e.g. myosin, kinesin) to perform mechanical work by leveraging a combination of energy sources and rich structural chemistry. Part I describes the synthesis, characterization, molecular dynamics, and switching properties of a series of `daisy chain' and oligorotaxane AMM prototypes. All compounds are templated by charge transfer and hydrogen bonding interactions between pi-associated 1,5-dioxynaphthlene donors appended with polyether groups and pi-acceptors of either neutral (naphthalenediimide) or charged (4,4´-bipyridinium) varieties, and are synthesized using efficient one-pot copper(I)-catalyzed azide-alkyne cycloaddition `click chemistry' protocols. The interlocked architectures of these rotaxanes enable them to express sophisticated secondary structures (i.e. foldamers) and mechanical motions in solution, which have been elucidated using dynamic 1H NMR spectroscopy. Furthermore, molecular dynamics simulations, cyclic voltammetry, and spectroelectrochemistry experiments have demonstrated

  6. Three-dimensional imaging of nanoscale materials by using coherent x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Jianwei

    2011-04-18

    X-ray crystallography is currently the primary methodology used to determine the 3D structure of materials and macromolecules. However, many nanostructures, disordered materials, biomaterials, hybrid materials and biological specimens are noncrystalline and, hence, their structures are not accessible by X-ray crystallography. Probing these structures therefore requires the employment of different approaches. A very promising technique currently under rapid development is X-ray diffraction microscopy (or lensless imaging), in which the coherent X-ray diffraction pattern of a noncrystalline specimen is measured and then directly phased to obtain a high-resolution image. Through the DOE support over the past three years, we have applied X-ray diffraction microscopy to quantitative imaging of GaN quantum dot particles, and revealed the internal GaN-Ga2O3 core shell structure in three dimensions. By exploiting the abrupt change in the scattering cross-section near electronic resonances, we carried out the first experimental demonstration of resonant X-ray diffraction microscopy for element specific imaging. We performed nondestructive and quantitative imaging of buried Bi structures inside a Si crystal by directly phasing coherent X-ray diffraction patterns acquired below and above the Bi M5 edge. We have also applied X-ray diffraction microscopy to nondestructive imaging of mineral crystals inside biological composite materials - intramuscular fish bone - at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization and proposed a dynamic mechanism to account for the nucleation and growth of mineral crystals in the collagen matrix. In addition, we have also discovered a novel 3D imaging modality, denoted ankylography, which allows for complete 3D structure determination without the necessity of sample titling or scanning. We showed that when the diffraction pattern of a finite object is sampled at a

  7. Interfaces in nanoscale photovoltaics

    NARCIS (Netherlands)

    Öner, S.Z.

    2016-01-01

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

  8. Transparent conductors based on microscale/nanoscale materials for high performance devices

    Science.gov (United States)

    Gao, Tongchuan

    Transparent conductors are important as the top electrode for a variety of optoelectronic devices, including solar cells, light-emitting diodes (LEDs), at panel displays, and touch screens. Doped indium tin oxide (ITO) thin films are the predominant transparent conductor material. However, ITO thin films are brittle, making them unsuitable for the emerging flexible devices, and suffer from high material and processing cost. In my thesis, we developed a variety of transparent conductors toward a performance comparable with or superior to ITO thin films, with lower cost and potential for scalable manufacturing. Metal nanomesh (NM), hierarchical graphene/metal microgrid (MG), and hierarchical metal NM/MG materials were investigated. Simulation methods were used as a powerful tool to predict the transparency and sheet resistance of the transparent conductors by solving Maxwell's equations and Poisson's equation. Affordable and scalable fabrication processes were developed thereafter. Transparent conductors with over 90% transparency and less than 10 O/square sheet resistance were successfully fabricated on both rigid and flexible substrates. Durability tests, such as bending, heating and tape tests, were carried out to evaluate the robustness of the samples. Haze factor, which characterizes how blurry a transparent conductor appears, was also studied in-depth using analytical calculation and numerical simulation. We demonstrated a tunable haze factor for metal NM transparent conductors and analyzed the principle for tuning the haze factor. Plasmonic effects, excited by some transparent conductors, can lead to enhanced performance in photovoltaic devices. We systematically studied the effect of incorporating metal NM into ultrathin film silicon solar cells using numerical simulation, with the aid of optimization algorithms to reduce the optimization time. Mechanisms contributing to the enhanced performance were then identified and analyzed. Over 72% enhancement in short

  9. Advanced Nanoscale Thin Film & Bulk Materials Towards Thermoelectric Power Conversion Efficiencies of 30%

    Science.gov (United States)

    2014-02-27

    effects were also observed for the first time in one of the most important TE materials, Bi2Te3, through a GaAs-Bi2Te3-air heterostructure . • RTI... heterostructure .  RTI successfully developed methods for controlled synthesis of 2 nm to 58 nm films at a very precisely-regulated deposition rate of 0.04 nm... nanowires compared to bulk silicon. This model also quantifies for the first time the surprisingly large contributions of phonons with long mean free

  10. Expanding the view into complex material systems: From micro-ARPES to nanoscale HAXPES

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, C.M. [Peter Gruenberg Institute (PGI-6) and JARA-FIT, Research Center Juelich, D-52425 Juelich (Germany); Fakultaet f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE), Universitaet Duisburg-Essen, D-47048 Duisburg (Germany); Wiemann, C.; Patt, M. [Peter Gruenberg Institute (PGI-6) and JARA-FIT, Research Center Juelich, D-52425 Juelich (Germany); Feyer, V. [Peter Gruenberg Institute (PGI-6) and JARA-FIT, Research Center Juelich, D-52425 Juelich (Germany); Sincrotrone Trieste S.C.p.A., S.S. 14, km 163.5 in Area Science Park, 34012 Basovizza, Trieste (Italy); Plucinski, L.; Krug, I.P. [Peter Gruenberg Institute (PGI-6) and JARA-FIT, Research Center Juelich, D-52425 Juelich (Germany); Escher, M.; Weber, N.; Merkel, M. [FOCUS GmbH, D-65510 Huenstetten (Germany); Renault, O. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Barrett, N. [DSM/IRAMIS/SPCSI, CEA-Saclay, F-91191 Gif sur Yvette Cedex (France)

    2012-10-15

    The analysis of chemical and electronic states in complex and nanostructured material systems requires electron spectroscopy to be carried out with nanometer lateral resolution, i.e. nanospectroscopy. This goal can be achieved by combining a parallel imaging photoelectron emission microscope with a bandpass energy filter. In this contribution we describe selected experiments employing a dedicated spectromicroscope - the NanoESCA. This instrument has a particular emphasis on the spectroscopic aspects and enables laterally resolved photoelectron spectroscopy from the VUV up into the hard X-ray regime.

  11. Mechanics of mass, energy and momentum transfer in complex textured materials at micro/nanoscales

    Science.gov (United States)

    Raman, Srikar

    The aim of this work is the investigation of the physical properties associated with nanostructured materials for various advanced applications which include controlled drug release, pressure driven nanofluidics, spray cooling etc. Polymer nanofibers (monolithic or core-shell) and turbostatic carbon nanotube bundles fabricated through electrospinning and co-electrospinning respectively were used as the key materials in this work. For controlled release applications, a model fluorescent dye Rhodamine 610 chloride, proteins, drugs or antigens encapsulated inside electrospun polymer nanofibers and its release to a buffer medium was analyzed. As a result of these experiments, it was discovered that the release process is limited by desorption process from nanopore surfaces. The experimental results were used as foundation as novel theory of release process and also allowed characterization of the relevant physical parameters of different compounds involved. In addition, thermal characterization of these electrospun polymer nanofibers was carried out to investigate their creep properties. The aim of this part was in the establishment of a detailed mechanism responsible for shrinkage of nanofiber mats at elevated temperatures and elucidation of its relation to the microscopic thermally-induced changes occurring in the polymer structure. In particular, thermal behavior of Poly(epsilon-caprolactone) (PCL), Poly(methylmethacrylate) (PMMA), Polyacrylonitrile (PAN) and Polyurethane (PU) in electrospun nanofibers and original pellets were studied using Differential Scanning Calorimetry (DSC) and linked to the onset of thermally-induced shrinkage of nanofiber mats. The elctrospinning setup was then extended to Co-electrospinning process for fabricating Turbostratic Carbon Nanotube Bundles, for pressure driven flow of suspensions. Using a model water soluble compound, fluorescent dye Rhodamine 610 chloride, it was shown that deposit buildup on the inner walls of the delivery

  12. Phase stability in nanoscale material systems: extension from bulk phase diagrams

    Science.gov (United States)

    Bajaj, Saurabh; Haverty, Michael G.; Arróyave, Raymundo; Goddard Frsc, William A., III; Shankar, Sadasivan

    2015-05-01

    Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed ``nano-CALPHAD'') is employed to investigate these changes in three binary systems by calculating their phase diagrams at nano dimensions and comparing them with their bulk counterparts. The surface energy contribution, which is the dominant factor in causing these changes, is evaluated using the spherical particle approximation. It is first validated with the Au-Si system for which experimental data on phase stability of spherical nano-sized particles is available, and then extended to calculate phase diagrams of similarly sized particles of Ge-Si and Al-Cu. Additionally, the surface energies of the associated compounds are calculated using DFT, and integrated into the thermodynamic model of the respective binary systems. In this work we found changes in miscibilities, reaction compositions of about 5 at%, and solubility temperatures ranging from 100-200 K for particles of sizes 5 nm, indicating the importance of phase equilibrium analysis at nano dimensions.Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed ``nano-CALPHAD'') is employed to investigate these changes in three binary systems by

  13. Atomic-scale observation of lithiation reaction front in nanoscale SnO2 materials

    KAUST Repository

    Nie, Anmin

    2013-07-23

    In the present work, taking advantage of aberration-corrected scanning transmission electron microscopy, we show that the dynamic lithiation process of anode materials can be revealed in an unprecedented resolution. Atomically resolved imaging of the lithiation process in SnO2 nanowires illustrated that the movement, reaction, and generation of b = [1Ì...1Ì...1] mixed dislocations leading the lithiated stripes effectively facilitated lithium-ion insertion into the crystalline interior. The geometric phase analysis and density functional theory simulations indicated that lithium ions initial preference to diffuse along the [001] direction in the {200} planes of SnO2 nanowires introduced the lattice expansion and such dislocation behaviors. At the later stages of lithiation, the Li-induced amorphization of rutile SnO2 and the formation of crystalline Sn and LixSn particles in the Li2O matrix were observed. © 2013 American Chemical Society.

  14. Germanium Silicon Alloy Anode Material Capable of Tunable Overpotential by Nanoscale Si Segregation.

    Science.gov (United States)

    Kim, Hyungki; Son, Yoonkook; Park, Chibeom; Lee, Min-Joon; Hong, Misun; Kim, Jungah; Lee, Minkyung; Cho, Jaephil; Choi, Hee Cheul

    2015-06-10

    We developed the novel electrode that enables fine control of overpotential by exploiting surface segregation that is the enrichment of one component at the surface of binary alloy. To realize this approach, we controlled the proportion of Si with low Li diffusivity at the surface by annealing the SiGe nanowire in H2 environment at various temperatures. The resulting SiGe nanowires annealed at 850 °C exhibited high reversible capacity (>1031 mA·h·g(-1)), and long cycle life (400 cycles) with high capacity retention (89.0%) at 0.2 C. This superior battery performance is attributed to the remaining unlithiated part acting as support frame to prevent pulverization of anode material, which results from the fine-tuning of overpotential by controlling the degree of Si segregation.

  15. Self-aligned local electrolyte gating of 2D materials with nanoscale resolution

    CERN Document Server

    Peng, Cheng; Nanot, Sebastien; Shiue, Ren-Jye; Grosso, Gabriele; Yang, Yafang; Hempel, Marek; Jarillo-Herrero, Pablo; Kong, Jing; Koppens, Frank H L; Englund, Dirk

    2016-01-01

    In the effort to make 2D materials-based devices smaller, faster, and more efficient, it is important to control charge carrier at lengths approaching the nanometer scale. Traditional gating techniques based on capacitive coupling through a gate dielectric cannot generate strong and uniform electric fields at this scale due to divergence of the fields in dielectrics. This field divergence limits the gating strength, boundary sharpness, and pitch size of periodic structures, and restricts possible geometries of local gates (due to wire packaging), precluding certain device concepts, such as plasmonics and transformation optics based on metamaterials. Here we present a new gating concept based on a dielectric-free self-aligned electrolyte technique that allows spatially modulating charges with nanometer resolution. We employ a combination of a solid-polymer electrolyte gate and an ion-impenetrable e-beam-defined resist mask to locally create excess charges on top of the gated surface. Electrostatic simulations ...

  16. Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

    Science.gov (United States)

    Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming

    2010-06-01

    This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices.

  17. Atomic-scale observation of lithiation reaction front in nanoscale SnO2 materials.

    Science.gov (United States)

    Nie, Anmin; Gan, Li-Yong; Cheng, Yingchun; Asayesh-Ardakani, Hasti; Li, Qianqian; Dong, Cezhou; Tao, Runzhe; Mashayek, Farzad; Wang, Hong-Tao; Schwingenschlögl, Udo; Klie, Robert F; Yassar, Reza S

    2013-07-23

    In the present work, taking advantage of aberration-corrected scanning transmission electron microscopy, we show that the dynamic lithiation process of anode materials can be revealed in an unprecedented resolution. Atomically resolved imaging of the lithiation process in SnO2 nanowires illustrated that the movement, reaction, and generation of b = [1[overline]1[overline]1] mixed dislocations leading the lithiated stripes effectively facilitated lithium-ion insertion into the crystalline interior. The geometric phase analysis and density functional theory simulations indicated that lithium ions initial preference to diffuse along the [001] direction in the {200} planes of SnO2 nanowires introduced the lattice expansion and such dislocation behaviors. At the later stages of lithiation, the Li-induced amorphization of rutile SnO2 and the formation of crystalline Sn and LixSn particles in the Li2O matrix were observed.

  18. Thermal decomposition of energetic materials 85: Cryogels of nanoscale hydrazinium diperchlorate in resorcinol-formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Tappan, Bryce C.; Brill, Thomas B. [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)

    2003-04-01

    The objective of this work was to try to desensitize an energetic material by using sol-gel processing and freeze drying to incorporate the energetic material into the fuel matrix on the nano (or at least submicron) particle size scale. Hydrazinium diperchlorate ([N{sub 2}H{sub 6}][ClO{sub 4}]{sub 2} or HP{sub 2}) and resorcinol-formaldehyde (RF) were chosen as the oxidizer and fuel, respectively. Solid loading up to 88% HP{sub 2} was achieved by using the sol gel-to-cryogel method. Various weight percentages of HP{sub 2} in RF were characterized by elemental analysis, scanning electron (SEM) and optical microscopy, T-jump/FTIR spectroscopy, DSC, and drop-weight impact. SEM indicated that 20-50 nm diameter HP{sub 2} plates aggregated into porous 400-800 nm size clusters. Below 80% HP{sub 2} the cryogels are less sensitive to impact than physical mixtures having the same ratios of HP{sub 2} and RF. The decomposition temperatures of the cryogels are higher than that of pure HP{sub 2}, which is consistent with their lower impact sensitivity. The heat of decomposition as measured at a low heating rate increases with increasing percentage of HP{sub 2}. The cryogels and physical mixtures release similar amounts of energy, but the cryogels exhibit mainly a single exotherm by DSC whereas the physical mixtures showed a two-step energy release. Flash pyrolysis revealed gaseous product ratios suggestive of more energy being released from the cryogels than the physical mixtures. Cryogels also burn faster by visual observation. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Surface interactions between nanoscale iron and organic material: Potential uses in water treatment process units

    Science.gov (United States)

    Storms, Max

    Membrane systems are among the primary emergent technologies in water treatment process units due to their ease of use, small physical footprint, and high physical rejection. Membrane fouling, the phenomena by which membranes become clogged or generally soiled, is an inhibitor to optimal efficiency in membrane systems. Novel, composite, and modified surface materials must be investigated to determine their efficacy in improving fouling behavior. Ceramic membranes derived from iron oxide nanoparticles called ferroxanes were coated with a superhydrophillic, zwitterionic polymer called poly (sulfobetaine methacrylate) (polySBMA) to form a composite ceramic-polymeric membrane. Membrane samples with and without polySBMA coating were subjected to fouling with a bovine serum albumin solution and fouling was observed by measuring permeate flux at 10 mL intervals. Loss of polySBMA was measured using total organic carbon analysis, and membrane samples were characterized using x-ray diffraction, scanning electron microscopy, and optical profilometry. The coated membrane samples decreased initial fouling rate by 27% and secondary fouling rate by 24%. Similarly, they displayed a 30% decrease in irreversible fouling during the initial fouling stage, and a 27% decrease in irreversible fouling in the secondary fouling stage; however, retention of polySBMA sufficient for improved performance was not conclusive. The addition of chemical disinfectants into drinking water treatment processes results in the formation of compounds called disinfection by-products (DBPs). The formation of DBPs occurs when common chemical disinfectants (i.e. chlorine) react with organic material. The harmful effects of DBP exposure require that they be monitored and controlled for public safety. This work investigated the ability of nanostructured hematite derived from ferroxane nanoparticles to remove organic precursors to DBPs in the form of humic acid via adsorption processes. The results show that p

  20. Understanding and Controlling Nanoscale Morphology in Self-Assembled Semiconducting Materials

    Science.gov (United States)

    Kang, Hyeyeon

    Self-assembled semiconducting materials have been rapidly developed for a range of applications. This work aims to control the morphology of nanostructured semiconductors to understand how their functions arise from the structural properties. The first part of this dissertation focuses on the formation of a bulk-heterojunction (BHJ) in the active layer of organic photovoltaics (OPV). A BHJ is a bicontinuous interpenetrating network of organic components. The phase separation of the electron donor and the acceptor is required to achieve a BHJ structure in the nanostructured morphology, which promotes an efficient charge transportation. The use of solvent additive is one of the strategies to control the spontaneous phase separation during the film formation. Low vapor pressure solvent additives are introduced to a polymer casting solution in a sequentially processed OPV system, to study the swelling effect on the phase separation. In particular, the change in crystallinity and vertical mixing will be intensively studied upon polymer swelling. As another strategy, we introduce a molecular structure change to fullerene derivatives. A small structural variation leads to a large enough contrast of their surface energy, which is attributed to different vertical phase separation in the active layer. It eventually allows us to examine photovoltaic performance and device physics. In the second part, mesoporous inorganic films are investigated by preparation from a nanocrystal solution or sol-gel precursors for solar energy applications. Mesoporous nanocrystal-based titania is synthesized for inorganic/organic hybrid solar cells. The effect of surface modification is examined by anchoring a fullerene derivative on to titania surface. 3D interconnected mesoporous tantalum nitride films are prepared via sol-gel method as photoanodes in solar water splitting. The simple synthetic method using polymer template enables us to successfully prepare nitride films with excellent pore

  1. New Developments for Radiation Enhancements from Metal Surfaces by Using Nanoscale Materials in the Membrane

    Science.gov (United States)

    Yamada, Koji; Matsuda, Masami

    2017-12-01

    The enhancements of thermal radiations from the surfaces of devices are very important for electric machines to prevent from heating up and/or efficiency degradations. In this investigation, new applications of micro-scale membrane of Si, SiO2 etc. on the metal surfaces have been studied to cool down the temperature without breaking insulations of the devices by selecting materials. The modified black-body radiations were sensitively detected by thermisters with sub-second responses. The optimum membrane thicknesses were successfully determined by subtractions a of radiation intensities between those at membranes with and without membrane, respectively. We obtained the best cooling condition in SiO2 membrane with 20μmt for an Al-plate of 10cmx10cmx1mmt. Further, we observed the detaching/attaching processes of massive molecule clusters from the metal surface as a sudden change in temperature changes just like the noises in the detectors. A characteristic pattern of temperature change was observed in diatomite membranes during the cooling process in a temperature range between 200-50°C. These radiation phenomena as a function of temperature might be available as a molecular analysis on the metal surface.

  2. Beyond condensed matter physics on the nanoscale: the role of ionic and electrochemical phenomena in the physical functionalities of oxide materials.

    Science.gov (United States)

    Kalinin, Sergei V; Borisevich, Albina; Fong, Dillon

    2012-12-21

    Novel physical functionality enabled by nanoscale control of materials has been the target of intense scientific exploration and interest for the last two decades, leading directly to the explosive growth of nanoscience and nanotechnology. However, this transition to nanometer scales also blurs the boundary between classical physical and electrochemical phenomena, due to smaller transport lengths, larger chemical and electrostatic potential gradients, and higher surface/volume ratios. While well-recognized for many decades in areas such as ferroelectricity, these phenomena remained largely outside the realm of condensed matter physics studies. Here, we offer a perspective on the role of electrochemical phenomena in the nanoscale physics of correlated oxides and summarize the challenges for local characterization of these behaviors.

  3. Neurotoxicity of nanoscale materials

    Directory of Open Access Journals (Sweden)

    Alokita Karmakar

    2014-03-01

    Full Text Available Nanotechnology has been applied in consumer products and commercial applications, showing a significant impact on almost all industries and all areas of society. Significant evidence indicates that manufactured nanomaterials and combustion-derived nanomaterials elicit toxicity in humans exposed to these nanomaterials. The interaction of the engineered nanomaterials with the nervous system has received much attention in the nanotoxicology field. In this review, the biological effects of metal, metal oxide, and carbon-based nanomaterials on the nervous system are discussed from both in vitro and in vivo studies. The translocation of the nanoparticles through the blood–brain barrier or nose to brain via the olfactory bulb route, oxidative stress, and inflammatory mechanisms of nanomaterials are also reviewed.

  4. Structure and Electrochemical Properties of a Mechanochemically Processed Silicon and Oxide-Based Nanoscale Composite as an Active Material for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Norihiro Shimoi

    2017-01-01

    Full Text Available Si is essential as an active material in Li-ion batteries because it provides both high charge and optimal cycling characteristics. A composite of Si particles, Cu particles, and pure H2O was realized to serve as an anode active material and optimize the charge–discharge characteristics of Li-ion batteries. The composite was produced by grinding using a planetary ball mill machine, which allowed for homogenous dispersion of nanoscale Cu3Si as Si–Cu alloy grains and nanoscale Si grains in each poly-Si particle produced. Furthermore, some Si particles were oxidized by H2O, and oxidized Si was distributed throughout the composite, mainly as silicon monoxide. As a result, each Si particle included silicon monoxide and conductive Cu3Si materials, allowing for effective optimization of the recharging and charge-discharge characteristics. Thus, a new and simple process was realized for synthesizing a Si active material composited with silicon oxides, including silicon monoxide. This Si-rich conductive material is suitable as an anode for Li-ion batteries with high charge and optimized cycling properties.

  5. 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.

  6. Material properties and applications of blended organic thin films with nanoscale domains deposited by RIR-MAPLE

    Science.gov (United States)

    Stiff-Roberts, Adrienne D.; McCormick, Ryan D.; Ge, Wangyao

    2015-03-01

    Resonant-infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit blended, organic thin-films with nanoscale domain sizes of constituent polymers, small molecules, or colloidal nanoparticles. In the emulsion-based RIR-MAPLE process, the target contains a nonpolar, organic solvent phase and a polar, water phase. The emulsion properties have a direct impact on the nanoscale morphology of single-component organic thin films, while the morphology of blended, organic thin films also depends on the RIR-MAPLE deposition mode. In addition to these fundamental aspects, applications of blended organic films (organic solar cells, anti-reflection coatings, and multi-functional surfaces) deposited by emulsion-based RIR-MAPLE are presented. Importantly, domain sizes in the blended films are critical to thin-film functionality.

  7. Graduated characterization method using a multi-well microplate for reducing reactivity of nanoscale zero valent iron materials

    OpenAIRE

    Hwang, Yuhoon; Salatas, Apostolos; Mines, Paul D.; Jakobsen, Mogens Havsteen; Andersen, Henrik Rasmus

    2015-01-01

    Even though nanoscale zero valent iron (nZVI) has been intensively studied for the treatment of a plethora of pollutants through reductive reaction, quantification of nZVI reactivity has not yet been standardized. Here, we adapted colorimetric assays for determining reductive activity of nZVI and its composites with other metals. The assay quantifies reduction products to avoid interfering reactions, such as sorption and volatilization. Three different reaction products, ammonium, phenol, and...

  8. Nanoscale controlled Li-insertion reaction induced by scanning electron-beam irradiation in a Li4Ti5O12 electrode material for lithium-ion batteries.

    Science.gov (United States)

    Kitta, Mitsunori; Kohyama, Masanori

    2017-05-10

    The development of a nanoscale battery reaction in an electrode material associated with in situ microscopic observation is significant to an understanding of the solid-state mechanism of a battery reaction. With a Li4Ti5O12 (LTO) crystal as the negative electrode of a Li-ion battery (LIB), we show that a nanoscale-controlled Li-insertion reaction can be produced by electron beam irradiation with scanning transmission electron microscopy (STEM). A selected area in a Li2O-coated thin LTO crystal was irradiated by the electron probe of STEM with a high beam intensity of 2.5 × 10(7) (electrons per nm(2)). Electron energy-loss spectroscopy (EELS) revealed that significant changes in the chemical feature occurred only in the high-dose irradiation area in the LTO specimen. The features of Li-K, Ti-L and O-K spectra in that area were completely equal to those of a Li7Ti5O12 (Li-LTO) phase, as an electrochemically Li-inserted LTO phase, in contrast to usual LTO-like spectra in the region surrounding the specimen. For a pristine LTO specimen without Li2O coating, no Li-insertion reaction was observed under the same irradiation conditions. The high-dose electron beam seems to induce the dissociation of Li2O, providing Li ions and electrons, and the rapid and directional growth of a Li-LTO phase along the electron beam in the LTO specimen, forming a nanoscale steep interface with the surrounding LTO phase. The present phenomenon is a new type of electron beam assisted chemical reaction in a solid state, and could have a large impact on the science and technology of battery materials.

  9. A molecular dynamics investigation into the mechanisms of subsurface damage and material removal of monocrystalline copper subjected to nanoscale high speed grinding

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Fang, Qihong, E-mail: fangqh1327@hnu.edu.cn [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Liu, Youwen [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan Province 410082 (China); College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan Province 410082 (China); Zhang, Liangchi [School of Mechanical and Manufacturing Engineering, The University of New South Wales, NSW 2052 (Australia)

    2014-06-01

    This paper investigates the mechanisms of subsurface damage and material removal of monocrystalline copper when it is under a nanoscale high speed grinding of a diamond tip. The analysis was carried out with the aid of three-dimensional molecular dynamics simulations. The key factors that would influence the deformation of the material were carefully explored by analyzing the chip, dislocation movement, and workpiece deformation, which include grinding speed, depth of cut, grid tip radius, crystal orientation and machining angle of copper. An analytical model was also established to predict the emission of partial dislocations during the nanoscale high speed grinding. The investigation showed that a higher grinding velocity, a larger tip radius or a larger depth of cut would result in a larger chipping volume and a greater temperature rise in the copper workpiece. A lower grinding velocity would produce more intrinsic stacking faults. It was also found that the transition of deformation mechanisms depends on the competition between the dislocations and deformation twinning. There is a critical machining angle, at which a higher velocity, a smaller tip radius, or a smaller depth of cut will reduce the subsurface damage and improve the smoothness of a ground surface. The established analytical model showed that the Shockley dislocation emission is most likely to occur with the crystal orientations of (0 0 1)[1 0 0] at 45° angle.

  10. Non-Planar Nano-Scale Fin Field Effect Transistors on Textile, Paper, Wood, Stone, and Vinyl via Soft Material-Enabled Double-Transfer Printing

    KAUST Repository

    Rojas, Jhonathan Prieto

    2015-05-01

    The ability to incorporate rigid but high-performance nano-scale non-planar complementary metal-oxide semiconductor (CMOS) electronics with curvilinear, irregular, or asymmetric shapes and surfaces is an arduous but timely challenge in enabling the production of wearable electronics with an in-situ information-processing ability in the digital world. Therefore, we are demonstrating a soft-material enabled double-transfer-based process to integrate flexible, silicon-based, nano-scale, non-planar, fin-shaped field effect transistors (FinFETs) and planar metal-oxide-semiconductor field effect transistors (MOSFETs) on various asymmetric surfaces to study their compatibility and enhanced applicability in various emerging fields. FinFET devices feature sub-20 nm dimensions and state-of-the-art, high-κ/metal gate stack, showing no performance alteration after the transfer process. A further analysis of the transferred MOSFET devices, featuring 1 μm gate length exhibits ION ~70 μA/μm (VDS = 2 V, VGS = 2 V) and a low sub-threshold swing of around 90 mV/dec, proving that a soft interfacial material can act both as a strong adhesion/interposing layer between devices and final substrate as well as a means to reduce strain, which ultimately helps maintain the device’s performance with insignificant deterioration even at a high bending state.

  11. Nanoscale Wicking

    Science.gov (United States)

    Zhou, Jijie; Sansom, Elijah; Gharib, Mory; Noca, Flavio

    2003-11-01

    A wick is a bundle of fibers that by capillary attraction draws up to be burned a steady supply of the oil in lamps. In textile research, wicking is the process by which liquids are transported across or along fibers by capillary action (of relevance to perspiration). A similar phenomenon was recently discovered in our lab with mats of nanoscale fibers. A droplet containing a surfactant solution was placed on top of a well-aligned mat of carbon nanotubes: wicking was then observed as a film of liquid propagating within the nanocarpet, such as a stain or drop absorbed into a textile fabric. The nanoscale wicking process in carbon nano-arrays offers a simple and enabling technology for the processing (transport, mixing, filtering) of picoliters of fluids without any need for confinement (nanochannel) or bulky driving pressure apparatus. In this work, nanoscale wicking properties are quantified as a function of surfactant activity and carbon nanoarray geometry. The biomolecular sieving capability of the nanotube arrays is also put to test by the addition of biomolecules, while using the wicking process as the fluid driving force.

  12. Graduated characterization method using a multi-well microplate for reducing reactivity of nanoscale zero valent iron materials

    DEFF Research Database (Denmark)

    Hwang, Yuhoon; Salatas, Apostolos; Mines, Paul D.

    2015-01-01

    Even though nanoscale zero valent iron (nZVI) has been intensively studied for the treatment of a plethora of pollutants through reductive reaction, quantification of nZVI reactivity has not yet been standardized. Here, we adapted colorimetric assays for determining reductive activity of n......ZVI and its composites with other metals. The assay quantifies reduction products to avoid interfering reactions, such as sorption and volatilization. Three different reaction products, ammonium, phenol, and aniline, generated as the result of reduction of nitrate, p-halophenols, and nitrobenzene...

  13. 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...

  14. Dependency of Tunneling-Magnetoresistance Ratio on Nanoscale Spacer Thickness and Material for Double MgO Based Perpendicular-Magnetic-Tunneling-Junction

    Science.gov (United States)

    Lee, Du-Yeong; Hong, Song-Hwa; Lee, Seung-Eun; Park, Jea-Gun

    2016-01-01

    It was found that in double MgO based perpendicular magnetic tunneling junction spin-valves ex-situ annealed at 400 °C, the tunneling magnetoresistance ratio was extremely sensitive to the material and thickness of the nanoscale spacer: it peaked at a specific thickness (0.40~0.53 nm), and the TMR ratio for W spacers (~134%) was higher than that for Ta spacers (~98%). This dependency on the spacer material and thickness was associated with the (100) body-centered-cubic crystallinity of the MgO layers: the strain enhanced diffusion length in the MgO layers of W atoms (~1.40 nm) was much shorter than that of Ta atoms (~2.85 nm) and the shorter diffusion length led to the MgO layers having better (100) body-centered-cubic crystallinity. PMID:27929031

  15. Introduction to the IEEE International Symposium on Applications of Ferroelectrics and International Symposium on Piezoresponse Force Microscopy and Nanoscale Phenomena in Polar Materials.

    Science.gov (United States)

    Ye, Zuo-Guang; Tan, Xiaoli; Bokov, Alexei A

    2012-09-01

    The 20th IEEE International Symposium on Applications of Ferroelectrics (ISAF) was held on July 24-27, 2011, in Vancouver, British Columbia, Canada, jointly with the International Symposium on Piezoresponse Force Microscopy and Nanoscale Phenomena in Polar Materials (PFM). Over a period of four days, approximately 400 scientists, engineers, and students from around the world presented their work and discussed the latest developments in the field of ferroelectrics, related materials, and their applications. It is particularly encouraging to see that a large number of students (115) were attracted to the joint conference and presented high-quality research works. This trend is not only important to this conference series, but more importantly, it is vital to the future of the ferroelectrics field.

  16. Nanoscale Graphene Disk: A Natural Functionally Graded Material-How is Fourier's Law Violated along Radius Direction of 2D Disk.

    Science.gov (United States)

    Yang, Nuo; Hu, Shiqian; Ma, Dengke; Lu, Tingyu; Li, Baowen

    2015-10-07

    In this Paper, we investigate numerically and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize functionally graded material (FGM) with only one material, NGDs. Different from previous studies on divergence/non-diffusive of thermal conductivity in nano-structures with different size, we found a novel non-homogeneous (graded) thermal conductivity along the radius direction in a single nano-disk structure. We found that, instead of a constant value, the NGD has a graded thermal conductivity along the radius direction. That is, Fourier's law of heat conduction is not valid in two dimensional graphene disk structures Moreover, we show the dependent of NGDs' thermal conductivity on radius and temperature. Our study might inspire experimentalists to develop NGD based versatile FGMs, improve understanding of the heat removal of hot spots on chips, and enhance thermoelectric energy conversion efficiency by two dimensional disk with a graded thermal conductivity.

  17. Dependency of Tunneling-Magnetoresistance Ratio on Nanoscale Spacer Thickness and Material for Double MgO Based Perpendicular-Magnetic-Tunneling-Junction

    Science.gov (United States)

    Lee, Du-Yeong; Hong, Song-Hwa; Lee, Seung-Eun; Park, Jea-Gun

    2016-12-01

    It was found that in double MgO based perpendicular magnetic tunneling junction spin-valves ex-situ annealed at 400 °C, the tunneling magnetoresistance ratio was extremely sensitive to the material and thickness of the nanoscale spacer: it peaked at a specific thickness (0.40~0.53 nm), and the TMR ratio for W spacers (~134%) was higher than that for Ta spacers (~98%). This dependency on the spacer material and thickness was associated with the (100) body-centered-cubic crystallinity of the MgO layers: the strain enhanced diffusion length in the MgO layers of W atoms (~1.40 nm) was much shorter than that of Ta atoms (~2.85 nm) and the shorter diffusion length led to the MgO layers having better (100) body-centered-cubic crystallinity.

  18. 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.

  19. Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing

    KAUST Repository

    Almuslem, A. S.

    2017-02-14

    In the recent past, with the advent of transient electronics for mostly implantable and secured electronic applications, the whole field effect transistor structure has been dissolved in a variety of chemicals. Here, we show simple water soluble nano-scale (sub-10 nm) germanium oxide (GeO) as the dissolvable component to remove the functional structures of metal oxide semiconductor devices and then reuse the expensive germanium substrate again for functional device fabrication. This way, in addition to transiency, we also show an environmentally friendly manufacturing process for a complementary metal oxide semiconductor (CMOS) technology. Every year, trillions of complementary metal oxide semiconductor (CMOS) electronics are manufactured and billions are disposed, which extend the harmful impact to our environment. Therefore, this is a key study to show a pragmatic approach for water soluble high performance electronics for environmentally friendly manufacturing and bioresorbable electronic applications.

  20. Contrast enhancement of biological nanoporous materials with zinc oxide infiltration for electron and X-ray nanoscale microscopy.

    Science.gov (United States)

    Ocola, L E; Sampathkumar, V; Kasthuri, N; Winarski, R P

    2017-07-19

    We show that using infiltration of ZnO metal oxide can be useful for high resolution imaging of biological samples in electron and X-ray microscopy. The method is compatible with standard fixation techniques that leave the sample dry, such as finishing with super critical CO2 drying, or simple vacuum drying up to 95 °C. We demonstrate this technique can be applied on tooth and brain tissue samples. We also show that high resolution X-ray tomography can be performed on biological systems using Zn K edge (1s) absorption to enhance internal structures, and obtained the first nanoscale 10 KeV X-ray absorption images of the interior regions of a tooth.

  1. Water soluble nano-scale transient material germanium oxide for zero toxic waste based environmentally benign nano-manufacturing

    Science.gov (United States)

    Almuslem, A. S.; Hanna, A. N.; Yapici, T.; Wehbe, N.; Diallo, E. M.; Kutbee, A. T.; Bahabry, R. R.; Hussain, M. M.

    2017-02-01

    In the recent past, with the advent of transient electronics for mostly implantable and secured electronic applications, the whole field effect transistor structure has been dissolved in a variety of chemicals. Here, we show simple water soluble nano-scale (sub-10 nm) germanium oxide (GeO2) as the dissolvable component to remove the functional structures of metal oxide semiconductor devices and then reuse the expensive germanium substrate again for functional device fabrication. This way, in addition to transiency, we also show an environmentally friendly manufacturing process for a complementary metal oxide semiconductor (CMOS) technology. Every year, trillions of complementary metal oxide semiconductor (CMOS) electronics are manufactured and billions are disposed, which extend the harmful impact to our environment. Therefore, this is a key study to show a pragmatic approach for water soluble high performance electronics for environmentally friendly manufacturing and bioresorbable electronic applications.

  2. Functionalising surfaces at the nanoscale using plasma technology.

    Science.gov (United States)

    Moore, R

    2009-01-01

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

  3. Optimum parameters for the production of nano-scale electrospun polycaprolactone to be used as a biomedical material

    Science.gov (United States)

    Ekram, Basma; Abdel-Hady, Bothaina M.; El-kady, Abeer M.; Amr, Sherif M.; Waley, Ahmed I.; Guirguis, Osiris W.

    2017-12-01

    Electrospun nano-polycaprolactone (PCL) is an ideal candidate for biomedical applications, as it mimics the extracellular matrix and possesses good biocompatibility, biodegradability and mechanical properties. Formic acid/acetic acid (FA/AA) and formic acid/acetone (FA/A) solvent systems were reported to be the safest solvents for the preparation of nanoscale electrospun polycaprolactone and they are also a common solvent with many natural polymers. In the present study a comparison between the electrospun fibers produced by the two systems was done. The optimum conditions for preparing PCL nanofibers were studied. The results indicated that finer fibers were found for formic acid/acetic acid in comparison with those produced by formic acid/acetone solvent system. In addition, it was found that optimum conditions for PCL nanofibers electrospinning were detected for 70:30 FA/AA solvent ratio with 15% PCL concentration and a tip to collector distance of 12.5 cm at 20 kV.

  4. EDITORIAL: Nanoscale metrology Nanoscale metrology

    Science.gov (United States)

    Klapetek, P.; Koenders, L.

    2011-09-01

    This special issue of Measurement Science and Technology presents selected contributions from the NanoScale 2010 seminar held in Brno, Czech Republic. It was the 5th Seminar on Nanoscale Calibration Standards and Methods and the 9th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized with the Czech Metrology Institute (CMI) and the Nanometrology Group of the Technical Committee-Length of EURAMET. There were two workshops that were integrated into NanoScale 2010: first a workshop presenting the results obtained in NANOTRACE, a European Metrology Research Project (EMRP) on displacement-measuring optical interferometers, and second a workshop about the European metrology landscape in nanometrology related to thin films, scanning probe microscopy and critical dimension. The aim of this workshop was to bring together developers, applicants and metrologists working in this field of nanometrology and to discuss future needs. For more information see www.co-nanomet.eu. The articles in this special issue of Measurement Science and Technology cover some novel scientific results. This issue can serve also as a representative selection of topics that are currently being investigated in the field of European and world-wide nanometrology. Besides traditional topics of dimensional metrology, like development of novel interferometers or laser stabilization techniques, some novel interesting trends in the field of nanometrology are observed. As metrology generally reflects the needs of scientific and industrial research, many research topics addressed refer to current trends in nanotechnology, too, focusing on traceability and improved measurement accuracy in this field. While historically the most studied standards in nanometrology were related to simple geometric structures like step heights or 1D or 2D gratings, now we are facing tasks to measure 3D structures and many unforeseen questions arising from interesting physical

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  6. Nanoscale 2013

    Science.gov (United States)

    Koenders, Ludger; Ducourtieux, Sebastien

    2014-04-01

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

  7. EDITORIAL: Nanoscale metrology Nanoscale metrology

    Science.gov (United States)

    Picotto, G. B.; Koenders, L.; Wilkening, G.

    2009-08-01

    Instrumentation and measurement techniques at the nanoscale play a crucial role not only in extending our knowledge of the properties of matter and processes in nanosciences, but also in addressing new measurement needs in process control and quality assurance in industry. Micro- and nanotechnologies are now facing a growing demand for quantitative measurements to support the reliability, safety and competitiveness of products and services. Quantitative measurements presuppose reliable and stable instruments and measurement procedures as well as suitable calibration artefacts to ensure the quality of measurements and traceability to standards. This special issue of Measurement Science and Technology presents selected contributions from the Nanoscale 2008 seminar held at the Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, in September 2008. This was the 4th Seminar on Nanoscale Calibration Standards and Methods and the 8th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized by the Nanometrology Group within EUROMET (The European Collaboration in Measurement Standards), the German Nanotechnology Competence Centre 'Ultraprecise Surface Figuring' (CC-UPOB), the Physikalisch-Technische Bundesanstalt (PTB) and INRIM. A special event during the seminar was the 'knighting' of Günter Wilkening from PTB, Braunschweig, Germany, as the 1st Knight of Dimensional Nanometrology. Günter Wilkening received the NanoKnight Award for his outstanding work in the field of dimensional nanometrology over the last 20 years. The contributions in this special issue deal with the developments and improvements of instrumentation and measurement methods for scanning force microscopy (SFM), electron and optical microscopy, high-resolution interferometry, calibration of instruments and new standards, new facilities and applications including critical dimension (CD) measurements on small and medium structures and nanoparticle

  8. Grain size and nanoscale effects on the nonlinear pull-in instability and vibrations of electrostatic actuators made of nanocrystalline material

    Science.gov (United States)

    Gholami, R.; Ansari, R.

    2018-01-01

    Presented herein is the study of grain size, grain surface energy and small scale effects on the nonlinear pull-in instability and free vibration of electrostatic nanoscale actuators made of nanocrystalline silicon (Nc-Si). A Mori–Tanaka micromechanical model is utilized to calculate the effective material properties of Nc-Si considering material structure inhomogeneity, grain size and grain surface energy. The small-scale effect is also taken into account using Mindlin’s strain gradient theory. Governing equations are derived in the discretized weak form using the variational differential quadrature method based on the third-order shear defamation beam theory in conjunction with the von Kármán hypothesis. The electrostatic actuation is modeled considering the fringing field effects based upon the parallel plate approximation. Moreover, the Casimir force effect is considered. The pseudo arc-length continuation technique is used to obtain the applied voltage-deflection curve of Nc-Si actuators. Then, a time-dependent small disturbance around the deflected configuration is assumed to solve the free vibration problem. By performing a numerical study, the influences of various factors such as length scale parameter, volume fraction of the inclusion phase, density ratio, average inclusion radius and Casimir force on the pull-in instability and free vibration of Nc-Si actuators are investigated.

  9. Improved Understanding of Space Radiation Effects on Exploration Electronics by Advanced Modeling of Nanoscale Devices and Novel Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA space exploration missions will use nanometer-scale electronic technologies which call for a shift in how radiation effects in such devices and materials...

  10. Predicting the Influence of Nano-Scale Material Structure on the In-Plane Buckling of Orthotropic Plates

    Science.gov (United States)

    Gates, Thomas S.; Odegard, Gregory M.; Nemeth, Michael P.; Frankland, Sarah-Jane V.

    2004-01-01

    A multi-scale analysis of the structural stability of a carbon nanotube-polymer composite material is developed. The influence of intrinsic molecular structure, such as nanotube length, volume fraction, orientation and chemical functionalization, is investigated by assessing the relative change in critical, in-plane buckling loads. The analysis method relies on elastic properties predicted using the hierarchical, constitutive equations developed from the equivalent-continuum modeling technique applied to the buckling analysis of an orthotropic plate. The results indicate that for the specific composite materials considered in this study, a composite with randomly orientated carbon nanotubes consistently provides the highest values of critical buckling load and that for low volume fraction composites, the non-functionalized nanotube material provides an increase in critical buckling stability with respect to the functionalized system.

  11. In vitro Alternative Methodologies for Central Nervous System Assessment: A Critique using Nanoscale Materials as an Example.

    Science.gov (United States)

    Identifying the potential health hazards to the central nervous system of a new family of materials presents many challenges. Whole-animal toxicity testing has been the tradition, but in vitro methods have been steadily gaining popularity. There are numerous challenges in testing...

  12. Chitosan capped nanoscale Fe-MIL-88B-NH2 metal-organic framework as drug carrier material for the pH responsive delivery of doxorubicin

    Science.gov (United States)

    Sivakumar, P.; Priyatharshni, S.; Nagashanmugam, K. B.; Thanigaivelan, A.; Kumar, K.

    2017-08-01

    In recent years nanoscale metal-organic frameworks (NMOFs) are contributing as an effective material for use in drug delivery and imaging applications due to their porous surfaces and easy surface modifications. In this work, Fe-MIL-88B-NH2 NMOFs were successfully synthesized on facile hydrothermal route and 2-aminoterephthalic acid (NH2-BDC) was employed as a bridging ligand to activate amine functional groups on the surface. Amine functional groups not only serve as a structure stabilizing agent but also enhance the loading efficiency of the doxorubicin (DOX) anticancer drug. A pH responsive DOX release was realized by introducing a positively charged chitosan (Chi) capping layer. Upon Chi-coating, cleavage was observed in the Fe-MIL-88B-NH2 structure at acidic pH, while gel-like insoluble structure was formed at basic pH. By utilizing this phenomenon, a pH responsive DOX release system was developed by using Chi capped Fe-MIL-88B-NH2 NMOFs under the designed pH (4.0-8.0). The results suggest the Chi capped Fe-MIL-88B-NH2 can be a promising candidate for future pH responsive drug delivery systems.

  13. In vivo micronucleus studies with 6 titanium dioxide materials (3 pigment-grade & 3 nanoscale) in orally-exposed rats.

    Science.gov (United States)

    Donner, E M; Myhre, A; Brown, S C; Boatman, R; Warheit, D B

    2016-02-01

    Six pigment-grade (pg) or ultrafine (uf)/nanoscale (anatase and/or rutile) titanium dioxide (TiO2) particulates were evaluated for in vivo genotoxicity (OECD 474 Guidelines) in male and female rats by two different laboratories. All test materials were robustly characterized. The BET surface areas of the pg and uf samples ranged from 7 to 17 m(2)/g and 50 to 82 m(2)/g respectively. The materials were assessed for induction of micronuclei and toxicity in bone marrow by analyzing peripheral blood reticulocytes (RETs) by flow cytometry. Single oral gavage doses of 500, 1000 or 2000 mg/kg body weight (bw) of each material were implemented with concurrent negative (water) and positive controls (cyclophosphamide). Approximately 48 and 72 h after exposure, blood samples were collected and 20,000 RETs per animal were analyzed. For each of the six tests, there were no biologically or toxicologically relevant increases in the micronucleated RET frequency in any TiO2 exposed group at either time point at any dose level. In addition, there were a lack of biologically relevant decreases in %RETs among total erythrocytes. All six TiO2 test substances were negative for in vivo genotoxicity effects; however, it is noted that the exposure to target tissues was likely negligible. One pigment grade and one ultrafine material each were evaluated for potential systemic exposure/uptake from the gastrointestinal tract by analysis of TiO2 into blood and liver. No significant increases in TiO2 over controls were measured in blood (48 or 72 h) or liver (72 h) following exposures to 2000 mg/kg bw TiO2. These data indicate that there was no absorption of the test material from the gastrointestinal tract into the blood circulation and the lack of genotoxic effects is therefore attributed to a lack of exposure due to the inability of the test material to migrate from the gastrointestinal tract into the blood and then into target tissues. Copyright © 2015 Elsevier Inc. All rights

  14. Non-extensivity of thermodynamics at the nanoscale in molecular spin crossover materials: a balance between surface and volume.

    Science.gov (United States)

    Félix, Gautier; Nicolazzi, William; Mikolasek, Mirko; Molnár, Gábor; Bousseksou, Azzedine

    2014-04-28

    The spin transition behavior in nanoparticles of molecular spin crossover (SCO) materials is investigated theoretically using a two-variable microscopic Ising-like model solved by Monte Carlo simulations. The extensive nature of the energy, and therefore the whole thermodynamics is affected by the increasing role of surface energetic parameters. As a consequence the pressure inside the nanoparticle is different from the external pressure of the bath. The difference of the surface energies between the low spin (LS) and the high spin (HS) states is the origin of the modification of the SCO properties at finite sizes (downshift of the transition temperature and loss of the hysteresis). On the other hand, the extensivity of the system can be controlled by the form of the nanoparticle. Hollow particles allow control of the surface to volume ratio. An important consequence of this effect is the conservation of the SCO properties as a function of size. A modification of the intermolecular interactions at the surface leads to a modification of the surface rigidity, and will impact also on the extensivity of the system. When increasing/decreasing the surface rigidity the global elasticity of the nanoparticle raises/decreases and enhances/reduces the cooperativity of the SCO material.

  15. Removal of Cr(VI from Water Using a New Reactive Material: Magnesium Oxide Supported Nanoscale Zero-Valent Iron

    Directory of Open Access Journals (Sweden)

    Alessio Siciliano

    2016-08-01

    Full Text Available The chromium pollution of water is an important environmental and health issue. Cr(VI removal by means of metallic iron is an attractive method. Specifically, nanoscopic zero valent iron (NZVI shows great reactivity, however, its applicability needs to be further investigated. In the present paper, NZVI was supported on MgO grains to facilitate the treatments for remediation of chromium-contaminated waters. The performances and mechanisms of the developed composite, in the removal of hexavalent chromium, were investigated by means of batch and continuous tests. Kinetic studies, under different operating conditions, showed that reduction of Cr(VI could be expressed by a pseudo second-order reaction kinetic. The reaction rate increased with the square of Fe(0 amount, while it was inversely proportional to the initial chromium concentration. The process performance was satisfactory also under uncontrolled pH, and a limited influence of temperature was observed. The reactive material was efficiently reusable for many cycles without any regeneration treatment. The performances in continuous tests were close to 97% for about 80 pore volume of reactive material.

  16. Spectral Analysis of Surface Controlled Phonon Transport in Nanophononic Metamaterials

    Science.gov (United States)

    Neogi, Sanghamitra; Donadio, Davide

    Phonon engineering in nanostructured semiconductors has shown promises to further advance the performance of energy applications beyond the state-of-the-art limit. In nanostructured materials, phonon transport is greatly affected by the surface nanoscale character. The concept of nanophononic metamaterial (NPM) was introduced recently to affect nanoscale thermal transport with the inclusion of local surface resonators. We carried out a systematic investigation of phonon transport in locally resonant silicon-based NPMs. We used classical equilibrium molecular dynamics and a Boltzmann transport equation approach with the relaxation time approximation to investigate the nature of phononic thermal transport in nanopatterned silicon membranes with thicknesses of the order of 10 nm and below. We find the presence of local surface resonators has a significant effect on the phonon dispersion and has a direct consequence of suppression of group velocities of phonons in the NPMs. We completed the investigation by relating nanoscale resonant character (geometry and material composition) with phonon scattering, and consequently, phonon transport in the locally resonant silicon membrane NPMs This project is funded by the program FP7-ENERGY-2012-1-2STAGE under Contract Number 309150.

  17. Photoresponsive nanoscale columnar transistors.

    Science.gov (United States)

    Guo, Xuefeng; Xiao, Shengxiong; Myers, Matthew; Miao, Qian; Steigerwald, Michael L; Nuckolls, Colin

    2009-01-20

    This study reports a general methodology for making stable high-performance photosensitive field effect transistors (FET) from self-assembled columns of polycyclic aromatic hydrocarbons by using single-walled carbon nanotubes (SWNTs) as point contacts. In particular, the molecules used in this work are liquid crystalline materials of tetra(dodecyloxy)hexabenzocoronenes (HBCs) that are able to self-organize into columnar nanostructures with a diameter similar to that of SWNTs and then form nanoscale columnar transistors. To rule out potential artifacts, 2 different structural approaches were used to construct devices. One approach is to coat thin films of HBCs onto the devices with the SWNT-metal junctions protected by hydrogensilsesquioxane resin (HSQ), and the other is to place a droplet of HBC exactly on the nanogaps of SWNT electrodes. Both types of devices showed typical FET behaviors, indicating that SWNT-molecule-SWNT nanojunctions are responsible for the electrical characteristics of the devices. After thermally annealing the devices, HBC molecules assembled into columnar structures and formed more efficacious transistors with increased current modulation and higher gate efficiency. More interestingly, when the devices were exposed to visible light, photocurrents with an on/off ratio of >3 orders of magnitude were observed. This study demonstrates that stimuli-responsive nanoscale transistors have the potential applications in ultrasensitive devices for environmental sensing and solar energy harvesting.

  18. Electroless Deposition and Nanolithography Can Control the Formation of Materials at the Nano-Scale for Plasmonic Applications

    Directory of Open Access Journals (Sweden)

    Maria Laura Coluccio

    2014-03-01

    Full Text Available The new revolution in materials science is being driven by our ability to manipulate matter at the molecular level to create structures with novel functions and properties. The aim of this paper is to explore new strategies to obtain plasmonic metal nanostructures through the combination of a top down method, that is electron beam lithography, and a bottom up technique, that is the chemical electroless deposition. This technique allows a tight control over the shape and size of bi- and three-dimensional metal patterns at the nano scale. The resulting nanostructures can be used as constituents of Surface Enhanced Raman Spectroscopy (SERS substrates, where the electromagnetic field is strongly amplified. Our results indicate that, in electroless growth, high quality metal nanostructures with sizes below 50 nm may be easily obtained. These findings were explained within the framework of a diffusion limited aggregation (DLA model, that is a simulation model that makes it possible to decipher, at an atomic level, the rules governing the evolution of the growth front; moreover, we give a description of the physical mechanisms of growth at a basic level. In the discussion, we show how these findings can be utilized to fabricate dimers of silver nanospheres where the size and shape of those spheres is controlled with extreme precision and can be used for very large area SERS substrates and nano-optics, for single molecule detection.

  19. Electroless deposition and nanolithography can control the formation of materials at the nano-scale for plasmonic applications

    KAUST Repository

    Coluccio, Maria Laura

    2014-03-27

    The new revolution in materials science is being driven by our ability to manipulate matter at the molecular level to create structures with novel functions and properties. The aim of this paper is to explore new strategies to obtain plasmonic metal nanostructures through the combination of a top down method, that is electron beam lithography, and a bottom up technique, that is the chemical electroless deposition. This technique allows a tight control over the shape and size of bi- and three-dimensional metal patterns at the nano scale. The resulting nanostructures can be used as constituents of Surface Enhanced Raman Spectroscopy (SERS) substrates, where the electromagnetic field is strongly amplified. Our results indicate that, in electroless growth, high quality metal nanostructures with sizes below 50 nm may be easily obtained. These findings were explained within the framework of a diffusion limited aggregation (DLA) model, that is a simulation model that makes it possible to decipher, at an atomic level, the rules governing the evolution of the growth front; moreover, we give a description of the physical echanisms of growth at a basic level. In the discussion, we show how these findings can be utilized to fabricate dimers of silver nanospheres where the size and shape of those spheres is controlled with extreme precision and can be used for very large area SERS substrates and nano-optics, for single molecule detection. 2014 by the authors; licensee MDPI, Basel, Switzerland.

  20. Nano-Scale Au Supported on Carbon Materials for the Low Temperature Water Gas Shift (WGS Reaction

    Directory of Open Access Journals (Sweden)

    Paula Sánchez

    2011-12-01

    Full Text Available Au-based catalysts supported on carbon materials with different structures such as graphite (G and fishbone type carbon nanofibers (CNF-F were prepared using two different methods (impregnation and gold-sol to be tested in the water gas shift (WGS reaction. Atomic absorption spectrometry, transmission electron microscopy (TEM, temperature-programmed oxidation (TPO, X-ray diffraction (XRD, Raman spectroscopy, elemental analyses (CNH, N2 adsorption-desorption analysis, temperature-programmed reduction (TPR and temperature-programmed decomposition were employed to characterize both the supports and catalysts. Both the crystalline nature of the carbon supports and the method of gold incorporation had a strong influence on the way in which Au particles were deposited on the carbon surface. The higher crystallinity and the smaller and well dispersed Au particle size were, the higher activity of the catalysts in the WGS reaction was noted. Finally, catalytic activity showed an important dependence on the reaction temperature and steam-to-CO molar ratio.

  1. 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...

  2. Probing the nanoscale interaction forces and elastic properties of organic and inorganic materials using force-distance (F-D) spectroscopy

    Science.gov (United States)

    Vincent, Abhilash

    Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in

  3. Biological applications of nanoscale materials

    Science.gov (United States)

    Liang, Chi-Hui

    2007-12-01

    The objective of my research work is to synthesize, characterize, design, and apply nanocrystals for biomedical use. Gold nanoparticles were synthesized in the presence of chitosan via reduction of HAuCl4 with sodium borohydride. The average particle size of gold nanoparticles was significantly affected with the concentration of chitosan added and was ranged between 5 and 30 nm. The gold-chitosan nanocomposites were formed by adsorbing chitosan molecules on the gold nanoparticles. CdSe/ZnS quantum dots were prepared by a solution phase synthetic method. A new route for the phase transfer of CdSe/ZnS quantum dots from non-polar solvents into aqueous solution was developed using hydrophobically modified polysaccharides, both chitosan and alginate. In addition, it was shown that CdSe/ZnS based polysaccharide nanoparticles effectively inhibited the proliferation of human ovarian cancer cell line SKOV-3 in vitro. The findings suggest that CdSe/ZnS quantum dot based polysaccharide nanoparticles not only act as a long-term biomarker but also have potential value in cancer therapy. A novel method for extracting magnetite nanoparticles from magnetotactic bacteria was developed by using co-surfactant. The problem of mass cultivation was solved by growing AMB-1 in Ca2+-alginate microbeads. To apply magnetotactic bacterial in biomedical applications, uptake of chitosan-capped CdSe/ZnS quantum dots on magnetotactic bacteria and introducing fluorescent magnetotactic bacteria into mouse macrophage cells was achieved. A general strategy is described which allows for constructing multifunctional magnetic nanocomposites based on bacterial magnetite nanoparticles. Specifically, core-shell structures of bacterial magnetite-CdSe ZnS and bacterial magnetite-gold nanocomplexes have been built in this way. Furthermore, design and synthesis multimodal contrast agents which are ultrasound and photoacoustic active are achieved by utilizing biocompatible gold nanorods self assembling on liquid perfluorocarbon particles. The probe is likely to provide richer information for a better understanding of the target and subsequent diagnosis. In summary, nanocrystals including gold, CdSe ZnS quantum dots, and bacterial magnetite and nanocomplexes including bacterial magnetite-quantum dots, bacterial magnetite-gold, gold-perfluorocarbon, quantum dots-chitosan, and quantum dots-alginate were successful synthesized. Some potential applications of these nanoparticles and nanocomplexes in biomedical engineering are explored.

  4. Bumpy, Sticky, and Shaky: Nanoscale Science and the Curriculum

    Science.gov (United States)

    Taylor, Amy; Jones, Gail; Pearl, Thomas P.

    2008-01-01

    Nanoscience, or the study of the world at the size of a billionth of a meter, has the potential to help students see how all of the sciences are related. Behavior of materials at the nanoscale differs from materials at the macroscale. This article introduces three nanoscale properties and how they relate to various science domains. Three…

  5. Developmental toxicity studies with 6 forms of titanium dioxide test materials (3 pigment-different grade & 3 nanoscale) demonstrate an absence of effects in orally-exposed rats.

    Science.gov (United States)

    Warheit, D B; Boatman, R; Brown, S C

    2015-12-01

    Six different commercial forms and sizes of titanium dioxide particles were tested in separate developmental toxicity assays. The three pigment-grade (pg) or 3 ultrafine (uf)/nanoscale (anatase and/or rutile) titanium dioxide (TiO2) particle-types were evaluated for potential maternal and developmental toxicity in pregnant rats by two different laboratories. All studies were conducted according to OECD Guideline 414 (Prenatal Developmental Toxicity Study). In addition, all test materials were robustly characterized. The BET surface areas of the pg and uf samples ranged from 7 to 17 m(2)/g and 50-82 m(2)/g respectively (see Table 1). The test substances were formulated in sterile water. In all of the studies, the formulations were administered by oral gavage to time-mated rats daily beginning around the time of implantation and continuing until the day prior to expected parturition. In 3 of the studies (uf-1, uf-3, & pg-1), the formulations were administered to Crl:CD(SD) rats beginning on gestation day (GD) 6 through GD 20. In 3 additional studies (uf-2, and pg-2, pg-3 TiO2 particles), the formulations were administered to Wistar rats beginning on GD 5 through 19. The dose levels used in all studies were 0, 100, 300, or 1000 mg/kg/day; control group animals were administered the vehicle. During the in-life portions of the studies, body weights, food consumption, and clinical observations before and after dosing were collected on a daily basis. All dams were euthanized just prior to expected parturition (GD 21 for Crl:CD(SD) rats and GD 20 for Wistar rats). The gross necropsies included an examination and description of uterine contents including counts of corpora lutea, implantation sites, resorptions, and live and dead fetuses. All live fetuses were sexed, weighed, and examined externally and euthanized. Following euthanasia, fresh visceral and head examinations were performed on selected fetuses. The fetal carcasses were then processed and examined for skeletal

  6. Mesophase Assembly of Nanoscale Prisms

    Science.gov (United States)

    Wang, Ziwei; Ou, Zihao; Chen, Qian; Luijten, Erik

    Predicting structures self-assembled from basic building blocks remains a central problem in materials design and engineering. Entropy-driven packing behavior has been studied extensively via simulations of hard objects. However, in many experimental systems intrinsic, highly anisotropic interactions play an important role as well, and can overwhelm the entropic effects of shape, especially on the nanoscale. As a result, omission of enthalpic effects in large-scale simulations leaves many essential mesophases unexplored. We perform Monte Carlo simulations of nanoscale prisms with properly modeled interactions, and demonstrate that these give rise to a novel plastic-crystal mesophase of prisms stacked with random in-plane orientations, organized on a 2D hexagonal lattice. These simulations explain direct experimental observations performed with liquid-phase transmission electron microscopy.

  7. 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.

  8. JCMT active surface control system: implementation

    Science.gov (United States)

    Smith, Ian A.

    1998-05-01

    The James Clerk Maxwell Telescope on the summit of Mauna Kea in Hawaii is a 15 meter sub-millimeter telescope which operates in the 350 microns to 2 millimeter region. The primary antenna surface consists of 276 panels, each of which is positioned by 3 stepper motors. In order to achieve the highest possible surface accuracy we are embarking upon a project to actively control the position of the panels adjuster system is based on a 6809 micro connected to the control computer by a GPIB interface. This system is slow and inflexible and it would prove difficult to build an active surface control system with it. Part of the upgrade project is to replace the existing micro with a 68060 VME micro. The poster paper will describe how the temperature of the antenna is monitored with the new system, how a Finite Element Analyses package transforms temperature changes into a series of panel adjuster moves, and how these moves are then applied to the surface. The FEA package will run on a high end Sun workstation. A series of DRAMA tasks distributed between the workstation and the Baja 68060 VxWorks Active Surface Control System micro will control the temperature monitoring, FEA and panel adjustment activities. Users can interact with the system via a Tcl/TK based GUI.

  9. Surface-Controlled Metal Oxide Resistive Memory

    KAUST Repository

    Ke, Jr-Jian

    2015-10-28

    To explore the surface effect on resistive random-access memory (ReRAM), the impact of surface roughness on the characteristics of ZnO ReRAM were studied. The thickness-independent resistance and the higher switching probability of ZnO ReRAM with rough surfaces indicate the importance of surface oxygen chemisorption on the switching process. Furthermore, the improvements in switching probability, switching voltage and resistance distribution observed for ReRAM with rough surfaces can be attributed to the stable oxygen adatoms under various ambience conditions. The findings validate the surface-controlled stability and uniformity of ReRAM and can serve as the guideline for developing practical device applications.

  10. Ultrafast Charge and Triplet State Formation in Diketopyrrolopyrrole Low Band Gap Polymer/Fullerene Blends: Influence of Nanoscale Morphology of Organic Photovoltaic Materials on Charge Recombination to the Triplet State

    Directory of Open Access Journals (Sweden)

    René M. Williams

    2017-01-01

    Full Text Available Femtosecond transient absorption spectroscopy of thin films of two types of morphologies of diketopyrrolopyrrole low band gap polymer/fullerene-adduct blends is presented and indicates triplet state formation by charge recombination, an important loss channel in organic photovoltaic materials. At low laser fluence (approaching solar intensity charge formation characterized by a 1350 nm band (in ~250 fs dominates in the two PDPP-PCBM blends with different nanoscale morphologies and these charges recombine to form a local polymer-based triplet state on the sub-ns timescale (in ~300 and ~900 ps indicated by an 1100 nm absorption band. The rate of triplet state formation is influenced by the morphology. The slower rate of charge recombination to the triplet state (in ~900 ps belongs to a morphology that results in a higher power conversion efficiency in the corresponding device. Nanoscale morphology not only influences interfacial area and conduction of holes and electrons but also influences the mechanism of intersystem crossing (ISC. We present a model that correlates morphology to the exchange integral and fast and slow mechanisms for ISC (SOCT-ISC and H-HFI-ISC. For the pristine polymer, a flat and unstructured singlet-singlet absorption spectrum (between 900 and 1400 nm and a very minor triplet state formation (5% are observed at low laser fluence.

  11. Force modulation for enhanced nanoscale electrical sensing

    NARCIS (Netherlands)

    Koelmans, W.W.; Sebastian, A.; Abelmann, Leon; Despont, M.; Pozidis, H.

    2011-01-01

    Scanning probe microscopy employing conductive probes is a powerful tool for the investigation and modification of electrical properties at the nanoscale. Application areas include semiconductor metrology, probe-based data storage and materials research. Conductive probes can also be used to emulate

  12. Nanoscale Vacuum Channel Transistor.

    Science.gov (United States)

    Han, Jin-Woo; Moon, Dong-Il; Meyyappan, M

    2017-04-12

    Vacuum tubes that sparked the electronics era had given way to semiconductor transistors. Despite their faster operation and better immunity to noise and radiation compared to the transistors, the vacuum device technology became extinct due to the high power consumption, integration difficulties, and short lifetime of the vacuum tubes. We combine the best of vacuum tubes and modern silicon nanofabrication technology here. The surround gate nanoscale vacuum channel transistor consists of sharp source and drain electrodes separated by sub-50 nm vacuum channel with a source to gate distance of 10 nm. This transistor performs at a low voltage (3 microamperes). The nanoscale vacuum channel transistor can be a possible alternative to semiconductor transistors beyond Moore's law.

  13. Weaving Nanoscale Cloth through Electrostatic Templating.

    Science.gov (United States)

    Champsaur, Anouck M; Mézière, Cécile; Allain, Magali; Paley, Daniel W; Steigerwald, Michael L; Nuckolls, Colin; Batail, Patrick

    2017-08-30

    Here we disclose a simple route to nanoscopic 2D woven structures reminiscent of the methods used to produce macroscopic textiles. We find that the same principles used in macroscopic weaving can be applied on the nanoscale to create two-dimensional molecular cloth from polymeric strands, a molecular thread. The molecular thread is composed of Co6Se8(PEt3)4L2 superatoms that are bridged with L = benzene bis-1,4-isonitrile to form polymer strands. As the superatoms that make up the polymer chain are electrochemically oxidized, they are electrostatically templated by a nanoscale anion, the tetragonal Lindqvist polyoxometalate Mo6O19(2-). The tetragonal symmetry of the dianionic template creates a nanoscale version of the box weave. The crossing points in the weave feature π-stacking of the bridging linker. By examining the steps in the weaving process with single crystal X-ray diffraction, we find that the degree of polymerization at the crossing points is crucial in the cloth formation. 2D nanoscale cloth will provide access to a new generation of smart, multifunctional materials, coatings, and surfaces.

  14. Nanoscale Laser Terahertz Emission Microscopy

    DEFF Research Database (Denmark)

    Klarskov, Pernille; Kim, Hyewon; Colvin, Vicki L.

    2017-01-01

    Laser terahertz emission microscopy (LTEM) has become a powerful tool for studying ultrafast dynamics and local fields in many different types of materials. This technique, which relies on acceleration of charge carriers in a material upon femtosecond excitation, can provide insight into the phys......Laser terahertz emission microscopy (LTEM) has become a powerful tool for studying ultrafast dynamics and local fields in many different types of materials. This technique, which relies on acceleration of charge carriers in a material upon femtosecond excitation, can provide insight...... into the physics of charge transport, built-in fields, grain boundaries or surface states. We describe a new implementation of LTEM with a spatial resolution in the nanoscale regime based on a scattering-type near-field tip-based approach. We observe a spectral reshaping of the signal compared to conventional LTEM......-size-limited spatial resolution of ∼20 nm by imaging a gold nanorod using terahertz emission from the underlying substrate. This work enables for the first time the possibility of performing LTEM measurements on individual nanostructures....

  15. 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

  16. 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.

  17. Field Effect Transistor in Nanoscale

    Science.gov (United States)

    2017-04-26

    AFRL-AFOSR-JP-TR-2017-0034 Field Effect Transistor in Nanoscale Swapan Pati JAWAHARLAL NEHRU CENTRE FOR ADVANCED SCIENTIFIC RESEARCH Final Report 04...Final 3. DATES COVERED (From - To) 28 Sep 2015 to 27 Sep 2016 4. TITLE AND SUBTITLE Field Effect Transistor in Nanoscale 5a.  CONTRACT NUMBER 5b...significant alteration in transport behaviour of these molecular junctions. 15. SUBJECT TERMS Theory, Nanoscale, Field Effect Transistor (FET), Devices

  18. Nanoscale Microelectronic Circuit Development

    Science.gov (United States)

    2011-06-17

    Project 3: Low-Power All-Digital Chip-to-Chip Interface Circuits by Pavan Kumar Hanumolu (OSU) CDADIC Project 4: Nanoscale Clock and Data Recovery...CDADIC Project 3: Low-Power All-Digital Chip-to-Chip Interface Circuits by Pavan Kumar Hanumolu (OSU) CDADIC Project 6: Stochastic and Passive A/D...Area 3: Reconfigurable Mixed-Signal Circuits CDADIC Project 3: Low-Power All-Digital Chip-to-Chip Interface Circuits by Pavan Kumar Hanumolu (OSU

  19. Nanoscale subsurface imaging

    Science.gov (United States)

    Soliman, M.; Ding, Y.; Tetard, L.

    2017-05-01

    The ability to probe structures and functional properties of complex systems at the nanoscale, both at their surface and in their volume, has drawn substantial attention in recent years. Besides detecting heterogeneities, cracks and defects below the surface, more advanced explorations of chemical or electrical properties are of great interest. In this article, we review some approaches developed to explore heterogeneities below the surface, including recent progress in the different aspects of metrology in optics, electron microscopy, and scanning probe microscopy. We discuss the principle and mechanisms of image formation associated with each technique, including data acquisition, data analysis and modeling for nanoscale structural and functional imaging. We highlight the advances based on atomic force microscopy (AFM). Our discussion first introduces methods providing structural information of the buried structures, such as position in the volume and geometry. Next we present how functional properties including conductivity, capacitance, and composition can be extracted from the modalities available to date and how they could eventually enable tomography reconstructions of systems such as overlay structures in transistors or living systems. Finally we propose a perspective regarding the outstanding challenges and needs to push the field forward.

  20. Nanoscale control of the network morphology of high efficiency polymer fullerene solar cells by the use of high material concentration in the liquid phase.

    Science.gov (United States)

    Radbeh, R; Parbaile, E; Bouclé, J; Di Bin, C; Moliton, A; Coudert, V; Rossignol, F; Ratier, B

    2010-01-22

    Despite the constant improvement of their power conversion efficiencies, organic solar cells based on an interpenetrating network of a conjugated polymer as donor and fullerene derivatives as acceptor materials still need to be improved for commercial use. In this context, we present a study on the optimization of solar cells based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) by varying a specific cell parameter, namely the concentration of the active layer components in the liquid phase before blend film deposition, in order to improve device performance and to better understand the relation between morphology and device operation. Our study shows a significant increase of the short-circuit current, open-circuit voltage and cell efficiency by properly choosing the formulation of the initial blend before film deposition. We demonstrate that the active layer morphology, which is strongly dependent on the initial material concentrations and the processing conditions, can greatly impact the electronic characteristics of the device, especially regarding charge recombination dynamics at the donor-acceptor interface. Our optimized P3HT:PCBM device exhibits both slow recombination and high photocurrent generation associated with an overall power conversion efficiency of 4.25% under 100 mW cm(-2) illumination (AM1.5G).

  1. 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.

  2. Pulsed-voltage atom probe tomography of low conductivity and insulator materials by application of ultrathin metallic coating on nanoscale specimen geometry.

    Science.gov (United States)

    Adineh, Vahid R; Marceau, Ross K W; Chen, Yu; Si, Kae J; Velkov, Tony; Cheng, Wenlong; Li, Jian; Fu, Jing

    2017-10-01

    We present a novel approach for analysis of low-conductivity and insulating materials with conventional pulsed-voltage atom probe tomography (APT), by incorporating an ultrathin metallic coating on focused ion beam prepared needle-shaped specimens. Finite element electrostatic simulations of coated atom probe specimens were performed, which suggest remarkable improvement in uniform voltage distribution and subsequent field evaporation of the insulated samples with a metallic coating of approximately 10nm thickness. Using design of experiment technique, an experimental investigation was performed to study physical vapor deposition coating of needle specimens with end tip radii less than 100nm. The final geometries of the coated APT specimens were characterized with high-resolution scanning electron microscopy and transmission electron microscopy, and an empirical model was proposed to determine the optimal coating thickness for a given specimen size. The optimal coating strategy was applied to APT specimens of resin embedded Au nanospheres. Results demonstrate that the optimal coating strategy allows unique pulsed-voltage atom probe analysis and 3D imaging of biological and insulated samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-09-01

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

  5. Depositing Materials on the Micro- and Nanoscale

    DEFF Research Database (Denmark)

    Mar, Mikkel Dysseholm; Herstrøm, Berit; Shkondin, Evgeniy

    2014-01-01

    on sequential introduction of precursor pulses with intermediate purging steps. The process proceeds by specific surface ligand-exchange reactions and this leads to layer-by-layer growth control. No other thin film deposition technique can approach the conformity achieved by ALD on high aspect ratio structures...

  6. Nanoscale Materials and Architectures for Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Grulke, Eric A. [Univ. of Kentucky, Lexington, KY (United States); Sunkara, Mahendra K. [University of Louisville, KY (United States)

    2011-05-25

    The Kentucky EPSCoR Program supported an inter-university, multidisciplinary energy-related research cluster studying nanomaterials for converting solar radiation and residual thermal energy to electrical energy and hydrogen. It created a collaborative center of excellence based on research expertise in nanomaterials, architectures, and their synthesis. The project strengthened and improved the collaboration between the University of Louisville, the University of Kentucky, and NREL. The cluster hired a new faculty member for ultra-fast transient spectroscopy, and enabled the mentoring of one research scientist, two postdoctoral scholars and ten graduate students. Work was accomplished with three focused cluster projects: organic and photoelectrochemical solar cells, solar fuels, and thermionic energy conversion.

  7. Silicon-Based Nanoscale Composite Energetic Materials

    Science.gov (United States)

    2013-02-01

    exposure to high temperatures during the reaction. Therefore, a mortar and pestle was used to slightly grind the product into a powder form. Typical...Interaction of Hydrogenated Porous Silicon with Oxygen at Cryogenic Temperatures. Physical Review Letters, 2001. 87(6). 20. Clement, D., et al

  8. Nanoscale Infrared Spectroscopy of Biopolymeric Materials

    Science.gov (United States)

    Curtis Marcott; Michael Lo; Kevin Kjoller; Craig Prater; Roshan Shetty; Joseph Jakes; Isao Noda

    2012-01-01

    Atomic Force Microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument capable of producing 100 nm spatial resolution IR spectra and images. This new capability enables the spectroscopic characterization of biomaterial domains at levels not previously possible. A tunable IR laser source generating pulses on the order of 10 ns was used...

  9. Combination of Two Nanoscale Quantum Systems by Controlled Manipulations

    Science.gov (United States)

    Li, Yang; Dilullo, Andrew; Fisher, Brandon; Hla, Saw-Wai

    2014-03-01

    Modifying properties of materials at the nanoscale is an important ability for bottom-up designs of new materials, nanodevices, which might lead to new applications in the future. One method to achieve this goal is to put two nanoscale systems together and then study how they influence the properties of each other. Scanning tunneling microscopes (STMs) are ideal tools for these manipulations. Here, we report one way to modify electronic properties of two nanoscale systems, vacancies and molecules, by a novel process of STM manipulation. By these manipulations, performed near 6 K, surface vacancies were controllably created on a noble metal surface. Molecules were selectively moved into the created vacancies. Scanning tunneling spectroscopy was used to measure the change of the electronic structures of this new vacancy and molecule complex. It was found that the energy spectrum of the vacancy-molecule complex was a combination of the vacancy electronic structure and signature molecular orbitals. This work demonstrates the controlled combination of two nanoscale quantum systems which resulted in definite overlap of the electronic states of the constituent parts. By this process it is possible to design and form a new class of nanoscale systems for future research. DOE, BES, SISGR Grant: DE-FG02-09ER16109.

  10. Micro- and nanoscale phenomena in tribology

    CERN Document Server

    Chung, Yip-Wah

    2011-01-01

    Drawn from presentations at a recent National Science Foundation Summer Institute on Nanomechanics, Nanomaterials, and Micro/Nanomanufacturing, Micro- and Nanoscale Phenomena in Tribology explores the convergence of the multiple science and engineering disciplines involved in tribology and the connection from the macro to nano world. Written by specialists from computation, materials science, mechanical engineering, surface physics, and chemistry, each chapter provides up-to-date coverage of both basic and advanced topics and includes extensive references for further study.After discussing the

  11. 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.

  12. Molecular Machines: Nanoscale gadgets

    Science.gov (United States)

    Garcia-Garibay, Miguel A.

    2008-06-01

    Meeting their biological counterparts halfway, artificial molecular machines embedded in liquid crystals, crystalline solids and mesoporous materials are poised to meet the demands of the next generation of functional materials.

  13. Dustiness of fine and nanoscale powders.

    Science.gov (United States)

    Evans, Douglas E; Turkevich, Leonid A; Roettgers, Cynthia T; Deye, Gregory J; Baron, Paul A

    2013-03-01

    Dustiness may be defined as the propensity of a powder to form airborne dust by a prescribed mechanical stimulus; dustiness testing is typically intended to replicate mechanisms of dust generation encountered in workplaces. A novel dustiness testing device, developed for pharmaceutical application, was evaluated in the dustiness investigation of 27 fine and nanoscale powders. The device efficiently dispersed small (mg) quantities of a wide variety of fine and nanoscale powders, into a small sampling chamber. Measurements consisted of gravimetrically determined total and respirable dustiness. The following materials were studied: single and multiwalled carbon nanotubes, carbon nanofibers, and carbon blacks; fumed oxides of titanium, aluminum, silicon, and cerium; metallic nanoparticles (nickel, cobalt, manganese, and silver) silicon carbide, Arizona road dust; nanoclays; and lithium titanate. Both the total and respirable dustiness spanned two orders of magnitude (0.3-37.9% and 0.1-31.8% of the predispersed test powders, respectively). For many powders, a significant respirable dustiness was observed. For most powders studied, the respirable dustiness accounted for approximately one-third of the total dustiness. It is believed that this relationship holds for many fine and nanoscale test powders (i.e. those primarily selected for this study), but may not hold for coarse powders. Neither total nor respirable dustiness was found to be correlated with BET surface area, therefore dustiness is not determined by primary particle size. For a subset of test powders, aerodynamic particle size distributions by number were measured (with an electrical low-pressure impactor and an aerodynamic particle sizer). Particle size modes ranged from approximately 300 nm to several micrometers, but no modes below 100 nm, were observed. It is therefore unlikely that these materials would exhibit a substantial sub-100 nm particle contribution in a workplace.

  14. Modeling nano-scale grain growth of intermetallics

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The Monte Carlo simulation is utilized to model the nano-scale grain growth of two nano- crystalline materials, Pd81Zr19 and RuAl. In this regard, the relationship between the real time and the time unit of simulation, i.e. Monte Carlo step (MCS), is determined. The results of modeling show that with increasing time ...

  15. Nanoscale optical imaging by atomic force infrared microscopy

    OpenAIRE

    Rice, James H.

    2010-01-01

    This review outlines progress in atomic force infrared microscopy, reviewing the methodology and its application in nanoscale infrared absorption imaging of both biological and functional materials, including an outline of where this emerging method has been applied to image cellular systems in aqueous environments.

  16. Adsorptive removal of fluoride from water using nanoscale ...

    African Journals Online (AJOL)

    The intraparticle diffusion was not a rate-controlling step for the adsorption process. Thus, the overall study indicates that nano-AlOOH is an efficient defluoridating material. KEY WORDS: Nanoscale AlOOH, Defluoridation, Fluoride removal efficiency, Adsorption capacity, Adsorption kinetics, Adsorption mechanism. Bull.

  17. Attosecond physics at the nanoscale.

    Science.gov (United States)

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

    2017-05-01

    Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds (1 attosecond  =  1 as  =  10 -18 s), which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is  ∼152 as. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this report on progress we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as above-threshold ionization and high-order harmonic generation. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nanophysics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the

  18. Light-matter interaction physics and engineering at the nanoscale

    CERN Document Server

    Weiner, John

    2013-01-01

    This book draws together the essential elements of classical electrodynamics, surface wave physics, plasmonic materials, and circuit theory of electrical engineering to provide insight into the essential physics of nanoscale light-matter interaction and to provide design methodology for practical nanoscale plasmonic devices. A chapter on classical and quantal radiation also highlights the similarities (and differences) between the classical fields of Maxwell's equations and the wave functions of Schrodinger's equation. The aim of this chapter is to provide a semiclassical picture of atomic absorption and emission of radiation, lending credence and physical plausibility to the "rules" of standard wave-mechanical calculations.

  19. Nanoscale NMR and NQR with Nitrogen Vacancy Centers

    Science.gov (United States)

    Urbach, Elana; Lovchinsky, Igor; Sanchez-Yamagishi, Javier; Choi, Soonwon; Bylinskii, Alexei; Dwyer, Bo; Andersen, Trond; Sushkov, Alex; Park, Hongkun; Lukin, Mikhail

    2016-05-01

    Nuclear quadrupole resonance (NQR) is a powerful tool which is used to detect quadrupolar interaction in nuclear spins with I > 1/2. Conventional NQR and NMR technology, however, rely on measuring magnetic fields from a macroscopic number of spins. Extending NMR and NQR techniques to the nanoscale could allow us to learn structural information about interesting materials and biomolecules. We present recent progress on using Nitrogen-Vacancy (NV) centers in diamond to perform room temperature nanoscale NMR and NQR spectroscopy on small numbers of nuclear spins in hexagonal boron nitride.

  20. Natively unfolded state for engineering nanoscale fibrillar arrays.

    Science.gov (United States)

    Ryadnov, Maxim G; Cherny, Dmitry I

    2012-02-01

    A generic rationale for the fabrication of high aspect ratio fibrillar nanoscale arrays is described. The design emulates an intermittence effect observed for β-structured α-synunclein fibrils, reported herein, in a structurally unrelated α-helical fiber. The generated nanoarrays are composed of periodic nanosized segments separated at uniform distances of unfolded regions. These regions can be targeted for conformational binding and refolding with metal nanoparticle-peptide conjugates for the conversion of fibrillar arrays into nanoparticle arrays. The introduced concept opens new strategies for engineering novel nanoscale materials and devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Nanoscale chemical mapping of laser-solubilized silk

    Science.gov (United States)

    Ryu, Meguya; Kobayashi, Hanae; Balčytis, Armandas; Wang, Xuewen; Vongsvivut, Jitraporn; Li, Jingliang; Urayama, Norio; Mizeikis, Vygantas; Tobin, Mark; Juodkazis, Saulius; Morikawa, Junko

    2017-11-01

    A water soluble amorphous form of silk was made by ultra-short laser pulse irradiation and detected by nanoscale IR mapping. An optical absorption-induced nanoscale surface expansion was probed to yield the spectral response of silk at IR molecular fingerprinting wavelengths with a high  ∼ 20 nm spatial resolution defined by the tip of the probe. Silk microtomed sections of 1–5 μm in thickness were prepared for nanoscale spectroscopy and a laser was used to induce amorphisation. Comparison of silk absorbance measurements carried out by table-top and synchrotron Fourier transform IR spectroscopy proved that chemical imaging obtained at high spatial resolution and specificity (able to discriminate between amorphous and crystalline silk) is reliably achieved by nanoscale IR. Differences in absorbance and spectral line-shapes of the bands are related to the different sensitivity of the applied methods to real and imaginary parts of permittivity. A nanoscale material characterization by combining synchrotron IR radiation and nano-IR is discussed.

  2. Coal surface control for advanced physical fine coal cleaning technologies

    Energy Technology Data Exchange (ETDEWEB)

    Morsi, B.I.; Chiang, S.H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Cheng, Y.S.; Gray, R.; Streeter, R.; Bi, H.; Campbell, P.; Chiarlli, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.; Venkatadri, R.

    1992-01-01

    This final report presents the research work carried out on the Coal Surface Control for Advanced Physical Fine Coal Cleaning Technologies project, sponsored by the US Department of Energy, Pittsburgh Energy Technology Center (DOE/PETC). The project was to support the engineering development of the selective agglomeration technology in order to reduce the sulfur content of US coals for controlling SO[sub 2] emissions (i.e., acid rain precursors). The overall effort was a part of the DOE/PETCs Acid Rain Control Initiative (ARCI). The overall objective of the project is to develop techniques for coal surface control prior to the advanced physical fine coal cleaning process of selective agglomeration in order to achieve 85% pyrite sulfur rejection at an energy recovery greater than 85% based on run-of-mine coal. The surface control is meant to encompass surface modification during grinding and laboratory beneficiation testing. The project includes the following tasks: Project planning; methods for analysis of samples; development of standard beneficiation test; grinding studies; modification of particle surface; and exploratory R D and support. The coal samples used in this project include three base coals, Upper Freeport - Indiana County, PA, Pittsburgh NO. 8 - Belmont County, OH, and Illinois No. 6 - Randolph County, IL, and three additional coals, Upper Freeport - Grant County- WV, Kentucky No. 9 Hopkins County, KY, and Wyodak - Campbell County, WY. A total of 149 drums of coal were received.

  3. 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...

  4. Ferroelectric crystals for photonic applications including nanoscale fabrication and characterization techniques

    CERN Document Server

    Ferraro, Pietro; De Natale, Paolo

    2015-01-01

    This book details the latest achievements in ferroelectric domain engineering and characterization at micro- and nano-scale dimensions and periods. It combines basic research of magnetic materials with device and production orientation.

  5. Sensing at the nanoscale

    Science.gov (United States)

    Demming, Anna; Hierold, Christofer

    2013-11-01

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

  6. Self-healing at the nanoscale

    Science.gov (United States)

    Amendola, Vincenzo; Meneghetti, Moreno

    2009-09-01

    The design of self-healing materials is a very important but challenging topic in nanotechnology. Self-healing strategies, also inspired by natural processes, allow the fabrication of auto-repairing systems, and in recent years, materials engineering at the nanoscale has allowed further advances in this emerging field. In this mini review, we recall some interesting self-healing systems found in natural processes and others created by man-made activity with special emphasis on the role played in this field by nanostructures. Finally, the self-healing of gold nanoparticles during laser irradiation is considered in more detail since it is a rare example of a functional nanomaterial with self-repairing properties.

  7. Microfluidic Generation of High-Viscosity Droplets by Surface-Controlled Breakup of Segment Flow.

    Science.gov (United States)

    Chen, Haosheng; Man, Jia; Li, Zhongnan; Li, Jiang

    2017-06-28

    Fluids containing high concentration polymers, sols, nanoparticles, etc., usually have high viscosities, and high-viscosity fluids are difficult to be encapsulated into uniform droplets. Here we report a surface-controlled breakup method to generate droplets directly from various aqueous and nonaqueous fluids with viscosities of 1.0 to 11.9 Pa s and a dispersed-to-continuous viscosity ratio up to 1000, whereas the volume fraction of droplets up to 50% can be achieved. It provides a straightforward method to encapsulate high viscosity fluids, in a well-controlled manner in the rapid developing droplet-based applications, including materials synthesis, drug delivery, cell assay, bioengineering, etc.

  8. Integrated nanoscale electronics and optoelectronics: Exploring nanoscale science and technology through semiconductor nanowires

    Science.gov (United States)

    Huang, Yu

    Semiconductor nanowires (NW) represent an ideal system for investigating low dimensional physics and are expected to play an important role as both interconnects and functional device elements in nanoscale electronic and optoelectronic devices. This thesis presents a series of key advances towards integrated nano-systems from the bottom-up approach using semiconductor NW building blocks. We first introduce a general approach to controlled synthesis of a broad range of semiconductor NWs via a metal cluster-catalyzed vapor-liquid-solid (VLS) growth mechanism. The diameter, length, and chemical composition of the NWs are controlled by the metal catalyst diameter, the growth time and vapor phase semiconductor reactants, respectively. Electrical transport studies demonstrate that these NWs can be doped to form n- or p-type material with carrier mobilities comparable to or larger than their bulk counterparts. Photoluminescence studies show that individual NWs exhibit good optical qualities and strong polarized emission. The excellent optic and electronic properties suggests that NWs are excellent candidates for building nanoscale electronics, photonics, and integrated optoelectronics. Subsequently, we demonstrate the development of hierarchical assembly methods used to organize NW building blocks into functional devices and complex architectures. In particular, electric fields and microfluidic flows have both been explored for the assembly of NWs with controlled spatial location and directionality. Next, we discuss a variety of conceptually new nanoscale electronic and photonic devices, and device integrations enabled by high quality NWs and flexible assembly methods. A wide range of nanoscale electronic devices have been demonstrated using NW building blocks, and several new nano-device concepts have been proposed and realized, including crossed-NW p-n diodes, crossed-NW field effect transistors (cNW-FETs) and molecule-gated NW-FETs. These devices can be constructed in

  9. Nanoscale high-temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, P.; Wei, J.Y.T.; Ananth, V.; Morales, P.; Skocpol, W

    2004-08-01

    We discuss the exciting prospects of studying high-temperature superconductivity in the nanometer scale from the perspective of experiments, theory and simulation. In addition to enabling studies of novel quantum phases in an unexplored regime of system dimensions and parameters, nanoscale high-temperature superconducting structures will allow exploration of fundamental mechanisms with unprecedented insight. The prospects include, spin-charge separation, detection of electron fractionalization via novel excitations such as vison, stripe states and their dynamics, preformed cooper pairs or bose-condensation in the underdoped regime, and other quantum-ordered states. Towards this initiative, we present the successful development of a novel nanofabrication technique for the epitaxial growth of nanoscale cuprates. Combining the techniques of e-beam lithography and nanomachining, we have been able to fabricate the first generation of high-temperature superconducting nanoscale devices, including Y-junctions, four-probe wires and rings. Their initial transport characterization and scanning tunneling microscopy reveal the integrity of the crystal structure, grown on nanometer scale lateral dimensions. Here, we present atomic force micrographs and electrical characterization of a few nanoscale YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) samples.

  10. Nanoscale structural modulation and enhanced room-temperature multiferroic properties

    Science.gov (United States)

    Sun, Shujie; Huang, Yan; Wang, Guopeng; Wang, Jianlin; Fu, Zhengping; Peng, Ranran; Knize, Randy J.; Lu, Yalin

    2014-10-01

    Availability of a single-phase multiferroic material functional at room temperature poses a big challenge, although it is very important to both fundamental physics and application development. Recently, layered Aurivillius oxide materials, one of the most promising candidates, have attracted considerable interest. In this work, we investigated the nanoscale structural evolution of the six-layer Bi7Fe3-xCoxTi3O21 when substituting excessive Co. Nanoscale structural modulation (NSM) occurred at the boundaries when changing the material gradually from the originally designed six-layer nanoscale architecture down to five and then four, when increasing the Co content, inducing a previously unidentified analogous morphotropic transformation (AMT) effect. The AMT's net contribution to the enhanced intrinsic multiferroic properties at room temperature was confirmed by quantifying and deducting the contribution from the existing impurity phase using derivative thermo-magneto-gravimetry measurements (DTMG). Significantly, this new AMT effect may be caused by a possible coupling contribution from co-existing NSM phases, indicating a potential method for realizing multiferroic materials that function at room temperature.Availability of a single-phase multiferroic material functional at room temperature poses a big challenge, although it is very important to both fundamental physics and application development. Recently, layered Aurivillius oxide materials, one of the most promising candidates, have attracted considerable interest. In this work, we investigated the nanoscale structural evolution of the six-layer Bi7Fe3-xCoxTi3O21 when substituting excessive Co. Nanoscale structural modulation (NSM) occurred at the boundaries when changing the material gradually from the originally designed six-layer nanoscale architecture down to five and then four, when increasing the Co content, inducing a previously unidentified analogous morphotropic transformation (AMT) effect. The AMT

  11. The Relationship between Nanoscale Architecture and Function in Photovoltaic Multichromophoric Arrays as Visualized by Kelvin Probe Force Microscopy

    NARCIS (Netherlands)

    Palermo, V.; Otten, M.B.J.; Liscio, A.; Schwartz, E.; de Witte, P.A.J.; Castriciano, M.A.; Wienk, M.M.; Nolde, F.; De Luca, G.M.; Cornelissen, Jeroen Johannes Lambertus Maria; Janssen, R.A.J.; Müllen, K.; Rowan, A.E.; Nolte, Roeland; Samori, P

    2008-01-01

    The physicochemical properties of organic (multi)component films for optoelectronic applications depend on both the mesoscopic and nanoscale architectures within the semiconducting material. Two main classes of semiconducting materials are commonly used: polymers and (liquid) crystals of small

  12. Recombinant protein-based nanoscale biomemory devices.

    Science.gov (United States)

    Yagati, A K; Min, J; Choi, J W

    2014-01-01

    Biomolecular computing devices that are based on the properties of biomolecular activities offer a unique possibility for constructing new computing structures. A new concept of using various biomolecules has been proposed in order to develop a protein-based memory device that is capable of switching physical properties when electrical input signals are applied to perform memory switching. To clarify the proposed concept, redox protein is immobilized on Au nanoelectrodes to catalyze reversible reactions of redox-active molecules, which is controlled electrochemically and reversibly converted between its ON/OFF states. In this review, we summarize recent research towards developing nanoscale biomemory devices including design, synthesis, fabrication, and functionalization based on the proposed concept. At first we analyze the memory function properties of the proposed device at bulk material level and then explain the WORM (write-once-read-many times) nature of the device, later we extend the analysis to multi-bit and multi-level storage functions, and then we focus the developments in nanoscale biomemory devices based on the electron transport of redox molecules to the underlying Au patterned surface. The developed device operates at very low voltages and has good stability and excellent reversibility, proving to be a promising platform for future memory devices.

  13. Coal surface control for advanced fine coal flotation

    Energy Technology Data Exchange (ETDEWEB)

    Fuerstenau, D.W.; Hanson, J.S.; Diao, J.; Harris, G.H.; De, A.; Sotillo, F. (California Univ., Berkeley, CA (United States)); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. (Columbia Univ., New York, NY (United States)); Hu, W.; Zou, Y.; Chen, W. (Utah Univ., Salt Lake City, UT (United States)); Choudhry, V.; Shea, S.; Ghosh, A.; Sehgal, R. (Praxis Engineers, Inc., Milpitas, CA (United States))

    1992-03-01

    The initial goal of the research project was to develop methods of coal surface control in advanced froth flotation to achieve 90% pyritic sulfur rejection, while operating at Btu recoveries above 90% based on run-of-mine quality coal. Moreover, the technology is to concomitantly reduce the ash content significantly (to six percent or less) to provide a high-quality fuel to the boiler (ash removal also increases Btu content, which in turn decreases a coal's emission potential in terms of lbs SO{sub 2}/million Btu). (VC)

  14. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    Science.gov (United States)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    The recent technological developments in the synthesis and characterization of high-quality nanostructures and developments in the theoretical techniques needed to model these materials, have motivated this focus section of Superconductor Science and Technology. Another motivation is the compelling evidence that all new superconducting materials, such as iron pnictides and chalcogenides, diborides (doped MgB2) and fullerides (alkali-doped C60 compounds), are heterostrucures at the atomic limit, such as the cuprates made of stacks of nanoscale superconducting layers intercalated by different atomic layers with nanoscale periodicity. Recently a great amount of interest has been shown in the role of lattice nano-architecture in controlling the fine details of Fermi surface topology. The experimental and theoretical study of superconductivity in the nanoscale started in the early 1960s, shortly after the discovery of the BCS theory. Thereafter there has been rapid progress both in experiments and the theoretical understanding of nanoscale superconductors. Experimentally, thin films, granular films, nanowires, nanotubes and single nanoparticles have all been explored. New quantum effects appear in the nanoscale related to multi-component condensates. Advances in the understanding of shape resonances or Fano resonances close to 2.5 Lifshitz transitions near a band edge in nanowires, 2D films and superlattices [1, 2] of these nanosized modules, provide the possibility of manipulating new quantum electronic states. Parity effects and shell effects in single, isolated nanoparticles have been reported by several groups. Theoretically, newer techniques based on solving Richardson's equation (an exact theory incorporating finite size effects to the BCS theory) numerically by path integral methods or solving the entire Bogoliubov-de Gennes equation in these limits have been attempted, which has improved our understanding of the mechanism of superconductivity in these confined

  15. Nanoscale mass conveyors

    Science.gov (United States)

    Regan, Brian C [Oakland, CA; Aloni, Shaul [Albany, CA; Zettl, Alexander K [Kensington, CA

    2008-03-11

    A mass transport method and device for individually delivering chargeable atoms or molecules from source particles is disclosed. It comprises a channel; at least one source particle of chargeable material fixed to the surface of the channel at a position along its length; a means of heating the channel; and a means for applying an controllable electric field along the channel, whereby the device transports the atoms or molecules along the channel in response to applied electric field. In a preferred embodiment, the mass transport device will comprise a multiwalled carbon nanotube (MWNT), although other one dimensional structures may also be used. The MWNT or other structure acts as a channel for individual or small collections of atoms due to the atomic smoothness of the material. Also preferred is a source particle of a metal such as indium. The particles move by dissociation into small units, in some cases, individual atoms. The particles are preferably less than 100 nm in size.

  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. Ultraslow waves on the nanoscale.

    Science.gov (United States)

    Tsakmakidis, Kosmas L; Hess, Ortwin; Boyd, Robert W; Zhang, Xiang

    2017-10-20

    There has recently been a surge of interest in the physics and applications of broadband ultraslow waves in nanoscale structures operating below the diffraction limit. They range from light waves or surface plasmons in nanoplasmonic devices to sound waves in acoustic-metamaterial waveguides, as well as fermions and phonon polaritons in graphene and van der Waals crystals and heterostructures. We review the underlying physics of these structures, which upend traditional wave-slowing approaches based on resonances or on periodic configurations above the diffraction limit. Light can now be tightly focused on the nanoscale at intensities up to ~1000 times larger than the output of incumbent near-field scanning optical microscopes, while exhibiting greatly boosted density of states and strong wave-matter interactions. We elucidate the general methodology by which broadband and, simultaneously, large wave decelerations, well below the diffraction limit, can be obtained in the above interdisciplinary fields. We also highlight a range of applications for renewable energy, biosensing, quantum optics, high-density magnetic data storage, and nanoscale chemical mapping. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. Adaptive Dynamic Surface Control for Generator Excitation Control System

    Directory of Open Access Journals (Sweden)

    Zhang Xiu-yu

    2014-01-01

    Full Text Available For the generator excitation control system which is equipped with static var compensator (SVC and unknown parameters, a novel adaptive dynamic surface control scheme is proposed based on neural network and tracking error transformed function with the following features: (1 the transformation of the excitation generator model to the linear systems is omitted; (2 the prespecified performance of the tracking error can be guaranteed by combining with the tracking error transformed function; (3 the computational burden is greatly reduced by estimating the norm of the weighted vector of neural network instead of the weighted vector itself; therefore, it is more suitable for the real time control; and (4 the explosion of complicity problem inherent in the backstepping control can be eliminated. It is proved that the new scheme can make the system semiglobally uniformly ultimately bounded. Simulation results show the effectiveness of this control scheme.

  19. Nanoscale geometric electric field enhancement in organic photovoltaics.

    Science.gov (United States)

    Pegg, Lara-Jane; Hatton, Ross A

    2012-06-26

    Generic design rules for electrode-organic semiconductor contacts that transcend specific materials are urgently required to guide the development of new electrodes and provide a framework for engineering this important class of interface. Herein a novel nanostructured window electrode is utilized in conjunction with three-dimensional electrostatic modeling to elucidate the importance of geometric electric field enhancement effects at the electrode interfaces in organic photovoltaics. The results of this study show that nanoscale protrusions at the electrode surfaces in organic photovoltaics dramatically improve the efficiency of photogenerated charge carrier extraction to the external circuit and that the origin of this improvement is the local amplification of the electrostatic field in the vicinity of said protrusions. This wholly geometric approach to engineering electrodes at the nanoscale is materials generic and can be employed to enhance the efficiency of charge carrier injection or extraction in a wide range of organic electronic devices.

  20. A hard X-ray nanoprobe beamline for nanoscale microscopy.

    Science.gov (United States)

    Winarski, Robert P; Holt, Martin V; Rose, Volker; Fuesz, Peter; Carbaugh, Dean; Benson, Christa; Shu, Deming; Kline, David; Stephenson, G Brian; McNulty, Ian; Maser, Jörg

    2012-11-01

    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.

  1. Nanoscale Electronic Devices

    Science.gov (United States)

    Jing, Xiaoye

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

  2. Comparison of Nanoscale Focused Ion Beam and Electrochemical Lithiation in β-Sn Microspheres

    Science.gov (United States)

    Takeuchi, Saya; McGehee, William R.; Schaefer, Jennifer L.; Wilson, Truman M.; Twedt, Kevin A.; Chang, Eddie H.; Soles, Christopher L.; Oleshko, Vladimir P.; McClelland, Jabez J.

    2017-01-01

    The development of Li focused ion beams (Li-FIB) enables controlled Li ion insertion into materials with nanoscale resolution. We take the first step toward establishing the relevance of the Li-FIB for studies of ion dynamics in electrochemically active materials by comparing FIB lithiation with conventional electrochemical lithiation of isolated β-Sn microspheres. Samples are characterized by cross-sectioning with Ga FIB and imaging via electron microscopy. The Li-FIB and electrochemical lithiated Sn exhibit similarities that suggest that the Li-FIB can be a powerful tool for exploring dynamical Li ion-material interactions at the nanoscale in a range of battery materials. PMID:28690337

  3. Nano-scale Electrodes for Molecular/Organic Electronics

    Institute of Scientific and Technical Information of China (English)

    K.Tsukagoshi

    2007-01-01

    1 Results Nanometer-scale electrodes with a nano-junction allow us to investigate conduction properties of nano-materials. Because many nano-materials usually form grain boundaries or domain boundaries with high tunneling resistance, it is difficult to investigate the intrinsic properties through a series of tunneling resistance. To make direct contact with the single nano-material, such as a single polymer string, we developed nano-scale electrodes. By using these nano-electrodes as new tool, we invest...

  4. 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.

  5. Nanoscale Synthesis and Characterization Laboratory Annual Report 2007

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, A V

    2008-04-07

    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 NSCL is delivering on its mission providing Laboratory programs with scientific solutions through the use of nanoscale synthesis and characterization. While this annual report summarizes 2007 activities, we have focused on nanoporous materials, advanced high strength, nanostructured metals, novel 3-dimensional lithography and characterization at the nanoscale for the past 3 years. In these three years we have synthesized the first monolithic nanoporous metal foams with less than 10% relative density; we have produced ultrasmooth nanocrystalline diamond inertial confinement fusion capsules; we have synthesized 3-dimensional graded density structures from full density to 5% relative density using nanolithography; and we have established ultrasmall angle x-ray scattering as a non-destructive tool to determine the structure on the sub 300nm scale. The NSCL also has a mission to recruit and to train personnel for Lab programs. The NSCL continues to attract talented scientists to the Laboratory. Andrew Detor from Massachusetts Institute of Technology, Sutapa Ghosal from the University of California, Irvine, Xiang Ying Wang from Shanghai Institute of Technology, and Arne Wittstock from University of Bremen joined the NSCL this year. The NSCL is pursuing four science and technology themes: nanoporous materials, advanced nanocrystalline materials, novel three-dimensional nanofabrication technologies, and nondestructive characterization at the mesoscale. The NSCL is also pursuing building new facilities for science and technology such as nanorobotics and atomic layer deposition.

  6. Characteristics for electrochemical machining with nanoscale voltage pulses.

    Science.gov (United States)

    Lee, E S; Back, S Y; Lee, J T

    2009-06-01

    Electrochemical machining has traditionally been used in highly specialized fields, such as those of the aerospace and defense industries. It is now increasingly being applied in other industries, where parts with difficult-to-cut material, complex geometry and tribology, and devices of nanoscale and microscale are required. Electric characteristic plays a principal function role in and chemical characteristic plays an assistant function role in electrochemical machining. Therefore, essential parameters in electrochemical machining can be described current density, machining time, inter-electrode gap size, electrolyte, electrode shape etc. Electrochemical machining provides an economical and effective method for machining high strength, high tension and heat-resistant materials into complex shapes such as turbine blades of titanium and aluminum alloys. The application of nanoscale voltage pulses between a tool electrode and a workpiece in an electrochemical environment allows the three-dimensional machining of conducting materials with sub-micrometer precision. In this study, micro probe are developed by electrochemical etching and micro holes are manufactured using these micro probe as tool electrodes. Micro holes and microgroove can be accurately achieved by using nanoscale voltages pulses.

  7. Bulk Nanostructured Materials

    Science.gov (United States)

    Koch, C. C.; Langdon, T. G.; Lavernia, E. J.

    2017-11-01

    This paper will address three topics of importance to bulk nanostructured materials. Bulk nanostructured materials are defined as bulk solids with nanoscale or partly nanoscale microstructures. This category of nanostructured materials has historical roots going back many decades but has relatively recent focus due to new discoveries of unique properties of some nanoscale materials. Bulk nanostructured materials are prepared by a variety of severe plastic deformation methods, and these will be reviewed. Powder processing to prepare bulk nanostructured materials requires that the powders be consolidated by typical combinations of pressure and temperature, the latter leading to coarsening of the microstructure. The thermal stability of nanostructured materials will also be discussed. An example of bringing nanostructured materials to applications as structural materials will be described in terms of the cryomilling of powders and their consolidation.

  8. 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

  9. 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.

  10. Endocytosis of Nanoscale Systems for Cancer Treatments.

    Science.gov (United States)

    Chen, Kai; Li, Xue; Zhu, Hongyan; Gong, Qiyong; Luo, Kui

    2017-04-28

    Advances of nanoscale systems for cancer treatment have been involved in enabling highly regulated site-specific localization to sub cellular organelles hidden beneath cell membranes. Thus far, the cellular entry of these nanoscale systems has been not fully understood. Endocytosisis a form of active transport in which cell transports elected extracellular molecules (such as proteins, viruses, micro-organisms and nanoscale systems) are allowed into cell interiors by engulfing them in an energy-dependent process. This process appears at the plasma membrane surface and contains internalization of the cell membrane as well as the membrane proteins and lipids of cell. There are multiform pathways of endocytosis for nanoscale systems. Further comprehension for the mechanisms of endocytosis is achieved with a combination of efficient genetic manipulations, cell dynamic imaging, and chemical endocytosis inhibitors. This review provides an account of various endocytic pathways, itemizes current methods to study endocytosis of nanoscale systems, discusses some factors associated with cellular uptake for nanoscale systems and introduces the trafficking behavior for nanoscale systems with active targeting. An insight into the endocytosis mechanism is urgent and significant for developing safe and efficient nanoscale systems for cancer diagnosis and therapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    Xiaoling He

    2008-01-01

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

  13. Nanoscale zinc antimonides: synthesis and phase stability.

    Science.gov (United States)

    Schlecht, Sabine; Erk, Christoph; Yosef, Maekele

    2006-02-20

    Highly crystalline single-phase nanoparticles of the important thermoelectric materials Zn4Sb3 and ZnSb were prepared from solvochemically activated powders of elemental zinc and elemental antimony. Low-temperature reactions with reaction temperatures of 275-300 degrees C were applied using an excess of elemental zinc. The nanoscale thermoelectrics obtained were characterized by X-ray powder diffraction, transmission electron microscopy, and thermal analysis. nc-Zn4Sb3 showed particle sizes of 50-70 nm, whereas particle sizes of 15-20 nm were observed for nc-ZnSb. Calorimetric investigations showed an increased heat capacity, Cp, for nc-Zn4Sb3 with respect to the bulk material which could be reduced to the bulk value by annealing nc-Zn4Sb3 at 190 degrees C. Interestingly, nc-Zn4Sb3 showed exothermic decomposition into zinc-poorer ZnSn at 196 degrees C in an open system, indicating that Zn4Sb3 is metastable in nanocrystalline form at room temperature.

  14. Crystal Engineering for Mechanical Strength at Nano-Scale Dimensions

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2017-10-01

    Full Text Available The mechanical strengths of nano-scale individual crystal or nanopolycrystalline metals, and other dimensionally-related materials are increased by an order of magnitude or more as compared to those values measured at conventional crystal or polycrystal grain dimensions. An explanation for the result is attributed to the constraint provided at the surface of the crystals or, more importantly, at interfacial boundaries within or between crystals. The effect is most often described in terms either of two size dependencies: an inverse dependence on crystal size because of single dislocation behavior or, within a polycrystalline material, in terms of a reciprocal square root of grain size dependence, designated as a Hall-Petch relationship for the researchers first pointing to the effect for steel and who provided an enduring dislocation pile-up interpretation for the relationship. The current report provides an updated description of such strength properties for iron and steel materials, and describes applications of the relationship to a wider range of materials, including non-ferrous metals, nano-twinned, polyphase, and composite materials. At limiting small nm grain sizes, there is a generally minor strength reversal that is accompanied by an additional order-of-magnitude elevation of an increased strength dependence on deformation rate, thus giving an important emphasis to the strain rate sensitivity property of materials at nano-scale dimensions.

  15. Nonlinear dynamics of nanoscale systems

    Science.gov (United States)

    Hodas, Nathan Oken

    This work builds theoretical tools to better understand nanoscale systems, and it ex- plores experimental techniques to probe nanoscale dynamics using nonlinear optical microscopy. In both the theory and experiment, this work harnesses nonlinearity to explore new boundaries in the ongoing attempts to understand the amazing world that is much smaller than we can see. In particular, the first part of this work proves the upper-bounds on the number and quality of oscillations when the sys- tem in question is homogeneously driven and has discrete states, a common way of describing nanoscale motors and chemical systems, although it has application to networked systems in general. The consequences of this limit are explored in the context of chemical clocks and limit cycles. This leads to the analysis of sponta- neous oscillations in GFPmut2, where we postulate that the oscillations must be due to coordinated rearrangement of the beta-barrel. Next, we utilize nonlinear optics to probe the constituent structures of zebrafish muscle. By comparing experimental observations with computational models, we show how second harmonic generation differs from fluorescence for confocal imaging. We use the wavelength dependence of the second harmonic generation conversion efficiency to extract information about the microscopic organization of muscle fibers, using the coherent nature of second ix harmonic generation as an analytical probe. Finally, existing experiments have used a related technique, sum-frequency generation, to directly probe the dynamics of free OH bonds at the water-vapor boundary. Using molecular dynamic simulations of the water surface and by designating surface-sensitive free OH bonds on the water surface, many aspects of the sum-frequency generation measurements were calcu- lated and compared with those inferred from experiment. The method utilizes results available from independent IR and Raman experiments to obtain some of the needed quantities, rather than

  16. Nanoscale integration is the next frontier for nanotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Samuel T [Los Alamos National Laboratory

    2009-01-01

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

  17. Nanoscale cryptography: opportunities and challenges

    Science.gov (United States)

    Masoumi, Massoud; Shi, Weidong; Xu, Lei

    2015-11-01

    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.

  18. 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.

  19. Attosecond physics at the nanoscale

    CERN Document Server

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

    2016-01-01

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

  20. Nanoscale mixing of soft solids.

    Science.gov (United States)

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

    2011-02-16

    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.

  1. 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.

  2. 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.

  3. Protein-Mediated Biotemplating on the Nanoscale

    Directory of Open Access Journals (Sweden)

    Amihay Freeman

    2017-08-01

    Full Text Available Purified proteins offer a homogeneous population of biological nanoparticles, equipped in many cases with specific binding sites enabling the directed self-assembly of envisaged one-, two- or three-dimensional arrays. These arrays may serve as nanoscale biotemplates for the preparation of novel functional composite materials, which exhibit potential applications, especially in the fields of nanoelectronics and optical devices. This review provides an overview of the field of protein-mediated biotemplating, focussing on achievements made throughout the past decade. It is comprised of seven sections designed according to the size and configuration of the protein-made biotemplate. Each section describes the design and size of the biotemplate, the resulting hybrid structures, the fabrication methodology, the analytical tools employed for the structural analysis of the hybrids obtained, and, finally, their claimed/intended applications and a feasibility demonstration (whenever available. In conclusion, a short assessment of the overall status of the achievements already made vs. the future challenges of this field is provided.

  4. 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

  5. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  6. Nanoscale Architectures for Energy Applications

    Science.gov (United States)

    Wong, Stanislaus

    2009-03-01

    In my group, we have developed a number of different potential architecture systems for gaining insights into energy storage and photovoltaics. In one manifestation of our efforts, generating a heterojunction comprising nanotubes and nanocrystals, externally bound and connected, has been significant. The unique, innovative, and important aspect of this particular nanoscale architecture is that it takes advantage of the tunability, in terms of size, shape, and chemistry, of nanotubes and nanocrystals, to create a sharp junction interface, whose properties are inherently manipulable, tailorable, and hence, predictable. For example, the electrical resistance of nanotube-nanoparticle networks is dependent on the nanoscale junctions that exist between these constituent nanomaterials as well as on microscale and macroscale connectivity. Thus, rational design of these nanomaterials is critical to a fundamental understanding of charge transport in single molecules and the determination of their conductance. Results on these systems can therefore be used to increase understanding of intrinsic factors affecting carrier mobility, such as electronic structure, carrier trapping, and delocalization. In a second manifestation, three-dimensional, dendritic micron- scale spheres of alkali metal hydrogen titanate 1D nanostructures (i.e.: nanowires and nanotubes) have been generated using a modified hydrothermal technique in the presence of hydrogen peroxide and an alkali metal hydroxide solution. Sea-urchin-like assemblies of these 1D nanostructures have been transformed into their hydrogen titanate analogues by neutralization as well as into their corresponding semiconducting, anatase titania nanostructured counterparts through a moderate high-temperature annealing dehydration process without destroying the 3D hierarchical structural motif. The as-prepared hollow spheres of titanate and titania 1D nanostructures have overall diameters, ranging from 0.8 μm to 1.2 μm, while the

  7. Striped nanoscale phase separation at the metal–insulator transition of heteroepitaxial nickelates

    Science.gov (United States)

    Mattoni, G.; Zubko, P.; Maccherozzi, F.; van der Torren, A.J.H.; Boltje, D. B.; Hadjimichael, M.; Manca, N.; Catalano, S.; Gibert, M.; Liu, Y.; Aarts, J.; Triscone, J.-M.; Dhesi, S. S.; Caviglia, A. D.

    2016-01-01

    Nucleation processes of mixed-phase states are an intrinsic characteristic of first-order phase transitions, typically related to local symmetry breaking. Direct observation of emerging mixed-phase regions in materials showing a first-order metal–insulator transition (MIT) offers unique opportunities to uncover their driving mechanism. Using photoemission electron microscopy, we image the nanoscale formation and growth of insulating domains across the temperature-driven MIT in NdNiO3 epitaxial thin films. Heteroepitaxy is found to strongly determine the nanoscale nature of the phase transition, inducing preferential formation of striped domains along the terraces of atomically flat stepped surfaces. We show that the distribution of transition temperatures is a local property, set by surface morphology and stable across multiple temperature cycles. Our data provide new insights into the MIT of heteroepitaxial nickelates and point to a rich, nanoscale phenomenology in this strongly correlated material. PMID:27804954

  8. Striped nanoscale phase separation at the metal-insulator transition of heteroepitaxial nickelates

    Science.gov (United States)

    Mattoni, G.; Zubko, P.; Maccherozzi, F.; van der Torren, A. J. H.; Boltje, D. B.; Hadjimichael, M.; Manca, N.; Catalano, S.; Gibert, M.; Liu, Y.; Aarts, J.; Triscone, J.-M.; Dhesi, S. S.; Caviglia, A. D.

    2016-11-01

    Nucleation processes of mixed-phase states are an intrinsic characteristic of first-order phase transitions, typically related to local symmetry breaking. Direct observation of emerging mixed-phase regions in materials showing a first-order metal-insulator transition (MIT) offers unique opportunities to uncover their driving mechanism. Using photoemission electron microscopy, we image the nanoscale formation and growth of insulating domains across the temperature-driven MIT in NdNiO3 epitaxial thin films. Heteroepitaxy is found to strongly determine the nanoscale nature of the phase transition, inducing preferential formation of striped domains along the terraces of atomically flat stepped surfaces. We show that the distribution of transition temperatures is a local property, set by surface morphology and stable across multiple temperature cycles. Our data provide new insights into the MIT of heteroepitaxial nickelates and point to a rich, nanoscale phenomenology in this strongly correlated material.

  9. Nanoscale imaging in DNA nanotechnology.

    Science.gov (United States)

    Jungmann, Ralf; Scheible, Max; Simmel, Friedrich C

    2012-01-01

    DNA nanotechnology has developed powerful techniques for the construction of precisely defined molecular structures and machines, and nanoscale imaging methods have always been crucial for their experimental characterization. While initially atomic force microscopy (AFM) was the most widely employed imaging method for DNA-based molecular structures, in recent years a variety of other techniques were adopted by researchers in the field, namely electron microscopy (EM), super-resolution fluorescence microscopy, and high-speed AFM. EM is now typically applied for the characterization of compact nanoobjects and three-dimensional (3D) origami structures, as it offers better resolution than AFM and can be used for 3D reconstruction from single-particle analysis. While the small size of DNA nanostructures had previously precluded the application of fluorescence microscopic methods, the development of super-resolution microscopy now facilities the application of fast and powerful optical methods also in DNA nanotechnology. In particular, the observation of dynamical processes associated with DNA nanoassemblies-e.g., molecular walkers and machines-requires imaging techniques that are both fast and allow observation under native conditions. Here single-molecule fluorescence techniques and high-speed AFM are beginning to play an increasingly important role. Copyright © 2011 Wiley Periodicals, Inc.

  10. Charge transport in nanoscale junctions.

    Science.gov (United States)

    Albrecht, Tim; Kornyshev, Alexei; Bjørnholm, Thomas

    2008-09-03

    Understanding the fundamentals of nanoscale charge transfer is pivotal for designing future nano-electronic devices. Such devices could be based on individual or groups of molecular bridges, nanotubes, nanoparticles, biomolecules and other 'active' components, mimicking wire, diode and transistor functions. These have operated in various environments including vacuum, air and condensed matter, in two- or three-electrode configurations, at ultra-low and room temperatures. Interest in charge transport in ultra-small device components has a long history and can be dated back to Aviram and Ratner's letter in 1974 (Chem. Phys. Lett. 29 277-83). So why is there a necessity for a special issue on this subject? The area has reached some degree of maturity, and even subtle geometric effects in the nanojunction and noise features can now be resolved and rationalized based on existing theoretical concepts. One purpose of this special issue is thus to showcase various aspects of nanoscale and single-molecule charge transport from experimental and theoretical perspectives. The main principles have 'crystallized' in our minds, but there is still a long way to go before true single-molecule electronics can be implemented. Major obstacles include the stability of electronic nanojunctions, reliable operation at room temperature, speed of operation and, last but not least, integration into large networks. A gradual transition from traditional silicon-based electronics to devices involving a single (or a few) molecule(s) therefore appears to be more viable from technologic and economic perspectives than a 'quantum leap'. As research in this area progresses, new applications emerge, e.g. with a view to characterizing interfacial charge transfer at the single-molecule level in general. For example, electrochemical experiments with individual enzyme molecules demonstrate that catalytic processes can be studied with nanometre resolution, offering a route towards optimizing biosensors at

  11. First evidence on phloem transport of nanoscale calcium oxide in groundnut using solution culture technique

    Science.gov (United States)

    Deepa, Manchala; Sudhakar, Palagiri; Nagamadhuri, Kandula Venkata; Balakrishna Reddy, Kota; Giridhara Krishna, Thimmavajjula; Prasad, Tollamadugu Naga Venkata Krishna Vara

    2015-06-01

    Nanoscale materials, whose size typically falls below 100 nm, exhibit novel chemical, physical and biological properties which are different from their bulk counterparts. In the present investigation, we demonstrated that nanoscale calcium oxide particles (n-CaO) could transport through phloem tissue of groundnut unlike the corresponding bulk materials. n-CaO particles are prepared using sol-gel method. The size of the as prepared n-CaO measured (69.9 nm) using transmission electron microscopic technique (TEM). Results of the hydroponics experiment using solution culture technique revealed that foliar application of n-CaO at different concentrations (10, 50, 100, 500, 1,000 ppm) on groundnut plants confirmed the entry of calcium into leaves and stems through phloem compared to bulk source of calcium sprayed (CaO and CaNO3). After spraying of n-CaO, calcium content in roots, shoots and leaves significantly increased. Based on visual scoring of calcium deficiency correction and calcium content in plant parts, we may establish the fact that nanoscale calcium oxide particles (size 69.9 nm) could move through phloem tissue in groundnut. This is the first report on phloem transport of nanoscale calcium oxide particles in plants and this result points to the use of nanoscale calcium oxide particles as calcium source to the plants through foliar application, agricultural crops in particular, as bulk calcium application through foliar nutrition is restricted due to its non-mobility in phloem.

  12. Nanoscale engineering of extracellular matrix-mimetic bioadhesive surfaces and implants for tissue engineering.

    Science.gov (United States)

    Shekaran, Asha; Garcia, Andres J

    2011-03-01

    The goal of tissue engineering is to restore tissue function using biomimetic scaffolds which direct desired cell fates such as attachment, proliferation and differentiation. Cell behavior in vivo is determined by a complex interaction of cells with extracellular biosignals, many of which exist on a nanoscale. Therefore, recent efforts in tissue engineering biomaterial development have focused on incorporating extracellular matrix- (ECM) derived peptides or proteins into biomaterials in order to mimic natural ECM. Concurrent advances in nanotechnology have also made it possible to manipulate protein and peptide presentation on surfaces on a nanoscale level. This review discusses protein and peptide nanopatterning techniques and examples of how nanoscale engineering of bioadhesive materials may enhance outcomes for regenerative medicine. Synergy between ECM-mimetic tissue engineering and nanotechnology fields can be found in three major strategies: (1) Mimicking nanoscale orientation of ECM peptide domains to maintain native bioactivity, (2) Presenting adhesive peptides at unnaturally high densities, and (3) Engineering multivalent ECM-derived peptide constructs. Combining bioadhesion and nanopatterning technologies to allow nanoscale control of adhesive motifs on the cell-material interface may result in exciting advances in tissue engineering. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine. 2010 Elsevier B.V. All rights reserved.

  13. Optics in the nanoscale limit for optoelectronics and biophotonics

    Science.gov (United States)

    Neogi, Arup

    2011-10-01

    Contemporary optical effects and photonic component necessary for the realization of nanoscale integrated photonic circuit for developing lab-on-a-chipincluding light sources, detectors and filters is summarized. We present the concept of a lab-on-a-chip for the next generation optoelectronics and biophotonic industry including novel nanoscale material systems for lasers and detectors. Using principles such as plasmonics and near-field optics highly efficient nano-photonic lasers or modulators can be realized. The light source can be tuned from the UV to the visible range using ion implantation of noble metal such as Ag or Au in Silicon or silica. The presence of Ag or Ag nanoparticles can result in a significant enhancement of the light emission in the UV, green or red wavelength regime. Novel molecular electronics materials has been used to design olegonucleotide based photodetectors on transparent substrates for the detection of analytes in an all-optical system. Either a transparent GaN semiconductor or glass can be used as an substrate. Hybrid photonic crystal based microfluidic channels synthesized using hydrogel material can be optimized to control the flow of fluid using light. In this paper, the device components developed at the University of North Texas will be presented for the realization of a lab-on-a-chip.

  14. NONLINEAR MODEL OF STABILITY STUDY OF SYSTEM "SURFACE CONTROL – ACTUATOR" OF MANEUVERABLE UNMANNED AERIAL VEHICLE

    Directory of Open Access Journals (Sweden)

    V. N. Akimov

    2017-01-01

    Full Text Available One of the important problems of the designing of maneuverable unmanned aerial vehicles (UAV is to ensure aeroelastic stability with automatic control system (ACS. One of the possible types of aeroelastic instability of UAV with ACS is loss of stability in the system "surface control – actuator".  A nonlinear model for the study of the stability of the system "surface control – actuator" is designed for solving problems of joint design of airframe and ACS with the requirements of aeroelasticity. The electric actuator is currently the most widely used on highly maneuverable UAV. The wide bandwidth and the availability of frequency characteristic lifts are typical for the modern electric actuator. This exacerbates the problem of providing aeroelastic stability of the UAV with ACS, including the problem of ensuring the stability of the system "surface control – actuator". In proposed model the surface control, performing bending-torsion oscillations in aerodynamic flow, in fact, is the loading for the actuator. Experimental frequency characteristics of the isolated actuator, obtained for different levels of the control signal, are used for the mathematical description of the actuator, then, as dynamic hinge moment, which is determined by aeroelastic vibrations of the surface control in the air flow, is calculated. Investigation of the stability of the system "surface control – actuator" is carried out by frequency method using frequency characteristics of the open-loop system. The undeniable advantage of the proposed model is the simplicity of obtaining the transfer functions of the isolated actuator. The experiment by its definition is a standard method of determining frequency characteristics of the actuator in contrast to time-consuming experiments for determining the dynamic stiffness of the actuator (with the surface control or the transfer function of the actuator using electromechanical simulation of aeroelastic loading of the

  15. 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.

  16. The Properties of Confined Water and Fluid Flow at the Nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Schwegler, E; Reed, J; Lau, E; Prendergast, D; Galli, G; Grossman, J C; Cicero, G

    2009-03-09

    This project has been focused on the development of accurate computational tools to study fluids in confined, nanoscale geometries, and the application of these techniques to probe the structural and electronic properties of water confined between hydrophilic and hydrophobic substrates, including the presence of simple ions at the interfaces. In particular, we have used a series of ab-initio molecular dynamics simulations and quantum Monte Carlo calculations to build an understanding of how hydrogen bonding and solvation are modified at the nanoscale. The properties of confined water affect a wide range of scientific and technological problems - including protein folding, cell-membrane flow, materials properties in confined media and nanofluidic devices.

  17. 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.

  18. Nanoscale phenomena in ferroelectric thin films

    Science.gov (United States)

    Ganpule, Chandan S.

    Ferroelectric materials are a subject of intense research as potential candidates for applications in non-volatile ferroelectric random access memories (FeRAM), piezoelectric actuators, infrared detectors, optical switches and as high dielectric constant materials for dynamic random access memories (DRAMs). With current trends in miniaturization, it becomes important that the fundamental aspects of scaling of ferroelectric and piezoelectric properties in these devices be studied thoroughly and their impact on the device reliability assessed. In keeping with this spirit of miniaturization, the dissertation has two broad themes: (a) Scaling of ferroelectric and piezoelectric properties and (b) The key reliability issue of retention loss. The thesis begins with a look at results on scaling studies of focused-ion-beam milled submicron ferroelectric capacitors using a variety of scanning probe characterization tools. The technique of piezoresponse microscopy, which is rapidly becoming an accepted form of domain imaging in ferroelectrics, has been used in this work for another very important application: providing reliable, repeatable and quantitative numbers for the electromechanical properties of submicron structures milled in ferroelectric films. This marriage of FIB and SPM based characterization of electromechanical and electrical properties has proven unbeatable in the last few years to characterize nanostructures qualitatively and quantitatively. The second half of this dissertation focuses on polarization relaxation in FeRAMs. In an attempt to understand the nanoscale origins of back-switching of ferroelectric domains, the time dependent relaxation of remnant polarization in epitaxial lead zirconate titanate (PbZr0.2Ti0.8O 3, PZT) ferroelectric thin films (used as a model system), containing a uniform 2-dimensional grid of 90° domains (c-axis in the plane of the film) has been examined using voltage modulated scanning force microscopy. A novel approach of

  19. Nanoscale heat transfer and thermoelectrics for alternative energy

    Science.gov (United States)

    Robinson, Richard

    2011-03-01

    In the area of alternative energy, thermoelectrics have experienced an unprecedented growth in popularity because of their ability to convert waste heat into electricity. Wired in reverse, thermoelectrics can act as refrigeration devices, where they are promising because they are small in size and lightweight, have no moving parts, and have rapid on/off cycles. However, due to their low efficiencies bulk thermoelectrics have historically been a niche market. Only in the last decade has thermoelectric efficiency exceeded ~ 20 % due to fabrication of nanostructured materials. Nanoscale materials have this advantage because electronic and acoustic confinement effects can greatly increase thermoelectric efficiency beyond bulk values. In this talk, I will introduce our work in the area of nanoscale heat transfer with the goal of more efficient thermoelectrics. I will discuss our experiments and methods to study acoustic confinement in nanostructures and present some of our new nanostructured thermoelectric materials. To study acoustic confinement we are building a nanoscale phonon spectrometer. The instrument can excite phonon modes in nanostructures in the ~ 100 s of GHz. Ballistic phonons from the generator are used to probe acoustic confinement and surface scattering effects. Transmission studies using this device will help optimize materials and morphologies for more efficient nanomaterial-based thermoelectrics. For materials, our group has synthesized nano-layer superlattices of Na x Co O2 . Sodium cobaltate was recently discovered to have a high Seebeck coeficent and is being studied as an oxide thermoelectric material. The thickness of our nano-layers ranges from 5 nm to 300 nm while the lengths can be varied between 10 μ m and 4 mm. Typical aspect ratios are 40 nm: 4 mm, or 1:100,000. Thermoelectric characterization of samples with tilted multiple-grains along the measurement axis indicate a thermoelectric efficiency on par with current polycrystalline samples

  20. Current trends in shrinking the channel length of organic transistors down to the nanoscale.

    Science.gov (United States)

    Cao, Yang; Steigerwald, Michael L; Nuckolls, Colin; Guo, Xuefeng

    2010-01-05

    In this Review article, we highlighted current trends in shrinking the channel length of organic field effect transistors (OFETs) down to the nanoscale in three systems where sophisticated device fabrication has been integrated into the development of different electrodes with nanoscale gaps. The design principle is the combination of molecular design freedom and flexible molecular self-assembly with state-of-the-art device fabrication to realize organic field effect nano-transistors where molecular materials themselves behave as pivotal elements. Three different types of nanoscale electrodes are used for OFETs: metals, single-walled carbon nanotubes (SWCNTs), and graphenes. These electrodes are made by e-beam lithography as well as other complementary methods (shadow deposition, underetching, nanoimprinting, rubber stamping, and microcontact printing).

  1. Deformation mechanisms in free-standing nanoscale thin films: A quantitative in situ transmission electron microscope study

    Science.gov (United States)

    Haque, M. A.; Saif, M. T. A.

    2004-01-01

    We have added force and displacement measurement capabilities in the transmission electron microscope (TEM) for in situ quantitative tensile experimentation on nanoscale specimens. Employing the technique, we measured the stress–strain response of several nanoscale free-standing aluminum and gold films subjected to several loading and unloading cycles. We observed low elastic modulus, nonlinear elasticity, lack of work hardening, and macroscopically brittle nature in these metals when their average grain size is 50 nm or less. Direct in situ TEM observation of the absence of dislocations in these films even at high stresses points to a grain-boundary-based mechanism as a dominant contributing factor in nanoscale metal deformation. When grain size is larger, the same metals regain their macroscopic behavior. Addition of quantitative capability makes the TEM a versatile tool for new fundamental investigations on materials and structures at the nanoscale. PMID:15084745

  2. 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

  3. Chromosome congression explained by nanoscale electrostatics.

    Science.gov (United States)

    Gagliardi, L John; Shain, Daniel H

    2014-02-24

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

  4. Molecular mechanistic origin of nanoscale contact, friction, and scratch in complex particulate systems.

    Science.gov (United States)

    Jalilvand, Soroosh; Shahsavari, Rouzbeh

    2015-02-11

    Nanoscale contact mechanisms, such as friction, scratch, and wear, have a profound impact on physics of technologically important particulate systems. Determining the key underlying interparticle interactions that govern the properties of the particulate systems has been long an engineering challenge. Here, we focus on particulate calcium-silicate-hydrate (C-S-H) as a model system and use atomistic simulations to decode the interplay between crystallographic directions, structural defects, and atomic species on normal and frictional forces. By exhibiting high material inhomogeneity and low structural symmetry, C-S-H provides an excellent system to explore various contact-induced nanoscale deformation mechanisms in complex particulate systems. Our findings provide a deep fundamental understanding of the role of inherent material features, such as van der Waals versus Coulombic interactions and the role of atomic species, in controlling the nanoscale normal contact, friction, and scratch mechanisms, thereby providing de novo insight and strategies for intelligent modulation of the physics of the particulate systems. This work is the first report on atomic-scale investigation of the contact-induced nanoscale mechanisms in structurally complex C-S-H materials and can potentially open new opportunities for knowledge-based engineering of several other particulate systems such as ceramics, sands, and powders and self-assembly of colloidal systems in general.

  5. Mechanical characterization of micro/nanoscale structures for MEMS/NEMS applications using nanoindentation techniques.

    Science.gov (United States)

    Li, Xiaodong; Bhushan, Bharat; Takashima, Kazuki; Baek, Chang-Wook; Kim, Yong-Kweon

    2003-01-01

    Mechanical properties of micro/nanoscale structures are needed to design reliable micro/nanoelectromechanical systems (MEMS/NEMS). Micro/nanomechanical characterization of bulk materials of undoped single-crystal silicon and thin films of undoped polysilicon, SiO(2), SiC, Ni-P, and Au have been carried out. Hardness, elastic modulus and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Fracture toughness was measured by indentation using a Vickers indenter. Bending tests were performed on the nanoscale silicon beams, microscale Ni-P and Au beams using a depth-sensing nanoindenter. It is found that the SiC film exhibits higher hardness, elastic modulus and scratch resistance as compared to other materials. In the bending tests, the nanoscale Si beams failed in a brittle manner with a flat fracture surface. The notched Ni-P beam showed linear deformation behavior followed by abrupt failure. The Au beam showed elastic-plastic deformation behavior. FEM simulation can well predict the stress distribution in the beams studied. The nanoindentation, scratch and bending tests used in this study can be satisfactorily used to evaluate the mechanical properties of micro/nanoscale structures for use in MEMS/NEMS.

  6. 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.

  7. Atomistic Design and Simulations of Nanoscale Machines and Assembly

    Science.gov (United States)

    Goddard, William A., III; Cagin, Tahir; Walch, Stephen P.

    2000-01-01

    Over the three years of this project, we made significant progress on critical theoretical and computational issues in nanoscale science and technology, particularly in:(1) Fullerenes and nanotubes, (2) Characterization of surfaces of diamond and silicon for NEMS applications, (3) Nanoscale machine and assemblies, (4) Organic nanostructures and dendrimers, (5) Nanoscale confinement and nanotribology, (6) Dynamic response of nanoscale structures nanowires (metals, tubes, fullerenes), (7) Thermal transport in nanostructures.

  8. XEDS STEM tomography for 3D chemical characterization of nanoscale particles.

    Science.gov (United States)

    Genc, Arda; Kovarik, Libor; Gu, Meng; Cheng, Huikai; Plachinda, Paul; Pullan, Lee; Freitag, Bert; Wang, Chongmin

    2013-08-01

    We present a tomography technique which couples scanning transmission electron microscopy (STEM) and X-ray energy dispersive spectrometry (XEDS) to resolve 3D distribution of elements in nanoscale materials. STEM imaging when combined with XEDS mapping using a symmetrically arranged XEDS detector design around the specimen overcomes many of the obstacles in 3D chemical imaging of nanoscale materials and successfully elucidates the 3D chemical information in a large field of view of the transmission electron microscopy (TEM) sample. We employed this technique to investigate 3D distribution of Nickel (Ni), Manganese (Mn) and Oxygen (O) in a Li1.2Ni0.2Mn0.6O2 (LNMO) nanoparticle used as a cathode material in Lithium (Li) ion batteries. For this purpose, 2D elemental maps were acquired for a range of tilt angles and reconstructed to obtain 3D elemental distribution in an isolated LNMO nanoparticle. The results highlight the strength of this technique in 3D chemical analysis of nanoscale materials by successfully resolving Ni, Mn and O elemental distributions in 3D and discovering the new phenomenon of Ni surface segregation in this material. Furthermore, the comparison of simultaneously acquired high angle annular dark field (HAADF) STEM and XEDS STEM tomography results shows that XEDS STEM tomography provides additional 3D chemical information of the material especially when there is low atomic number (Z) contrast in the material of interest. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Ceramic nanostructure materials, membranes and composite layers

    NARCIS (Netherlands)

    Burggraaf, A.J.; Keizer, Klaas; van Hassel, B.A.

    1989-01-01

    Synthesis methods to obtain nanoscale materials will be briefly discussed with a focus on sol-gel methods. Three types of nanoscale composites (powders, membranes and ion implanted layers) will be discussed and exemplified with recent original research results. Ceramic membranes with a thickness of

  10. Nano-Scale Characterization of Al-Mg Nanocrystalline Alloys

    Science.gov (United States)

    Harvey, Evan; Ladani, Leila

    Materials with nano-scale microstructure have become increasingly popular due to their benefit of substantially increased strengths. The increase in strength as a result of decreasing grain size is defined by the Hall-Petch equation. With increased interest in miniaturization of components, methods of mechanical characterization of small volumes of material are necessary because traditional means such as tensile testing becomes increasingly difficult with such small test specimens. This study seeks to characterize elastic-plastic properties of nanocrystalline Al-5083 through nanoindentation and related data analysis techniques. By using nanoindentation, accurate predictions of the elastic modulus and hardness of the alloy were attained. Also, the employed data analysis model provided reasonable estimates of the plastic properties (strain-hardening exponent and yield stress) lending credibility to this procedure as an accurate, full mechanical characterization method.

  11. 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.

  12. 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.

  13. Anomalous freezing behavior of nanoscale liposomes

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  14. Nanoscale temperature sensing using the Seebeck effect

    NARCIS (Netherlands)

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

    2012-01-01

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

  15. Performance assessment of nanoscale Schottky MOSFET as ...

    Indian Academy of Sciences (India)

    pp. 511–520. Performance assessment of nanoscale Schottky MOSFET as resonant tunnelling device: Non-equilibrium Green's function formalism ... 2School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran. *Corresponding author. E-mail: z.ahangari@iausr.ac.ir. MS received 2 January 2013; ...

  16. 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...

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

    African Journals Online (AJOL)

    Nanoscale science and nanotechnology is a rapidly growing and multidisciplinary field with its footing in chemistry, physics, molecular biology and engineering. It has led to breakthroughs in energy, environmental science, agriculture, biotechnology and several others. it is also capable of making a positive and significant ...

  18. Comb-like polymers inside nanoscale pores

    OpenAIRE

    Gay, Cyprien; Raphael, Elie

    2000-01-01

    A new method of polymer characterization, based on permeation studies using nanoscale pores, was recently proposed by Brochard and de Gennes. In the present paper, we study how this method, initially developped for star polymers can be extended to comb-like polymers.

  19. A nanoscale pn junction in series with tunable Schottky barriers

    Science.gov (United States)

    Aspitarte, Lee; McCulley, Daniel R.; Minot, Ethan D.

    2017-10-01

    PN junctions in nanoscale materials are of interest for a range of technologies including photodetectors, solar cells, and light-emitting diodes. However, Schottky barriers at the interface between metal contacts and the nanomaterial are often unavoidable. The effect of metal-semiconductor interfaces on the behavior of nanoscale diodes must be understood, both to extract the characteristics of the pn junction, and to understand the overall characteristics of the final device. Here, we study the current-voltage characteristics of diodes that are formed in fully suspended carbon nanotubes (CNTs). We utilize tunable Schottky barrier heights at the CNT-metal interface to elucidate the role of the Schottky barriers on the device characteristics. We develop a quantitative model to show how a variety of device characteristics can arise from apparently similar devices. Using our model we extract key parameters of the Schottky barriers and the pn junction, and predict the overall I-V characteristics of the device. Our equivalent circuit model is relevant to a variety of nanomaterial-based diode devices that are currently under investigation.

  20. Nanoscale fullerene compression of an yttrium carbide cluster.

    Science.gov (United States)

    Zhang, Jianyuan; Fuhrer, Tim; Fu, Wujun; Ge, Jiechao; Bearden, Daniel W; Dallas, Jerry; Duchamp, James; Walker, Kenneth; Champion, Hunter; Azurmendi, Hugo; Harich, Kim; Dorn, Harry C

    2012-05-23

    The nanoscale parameters of metal clusters and lattices have a crucial influence on the macroscopic properties of materials. Herein, we provide a detailed study on the size and shape of isolated yttrium carbide clusters in different fullerene cages. A family of diyttrium endohedral metallofullerenes with the general formula of Y(2)C(2n) (n = 40-59) are reported. The high field (13)C nuclear magnetic resonance (NMR) and density functional theory (DFT) methods are employed to examine this yttrium carbide cluster in certain family members, Y(2)C(2)@D(5)(450)-C(100), Y(2)C(2)@D(3)(85)-C(92), Y(2)C(2)@C(84), Y(2)C(2)@C(3v)(8)-C(82), and Y(2)C(2)@C(s)(6)-C(82). The results of this study suggest that decreasing the size of a fullerene cage with the same (Y(2)C(2))(4+) cluster results in nanoscale fullerene compression (NFC) from a nearly linear stretched geometry to a constrained "butterfly" structure. The (13)C NMR chemical shift and scalar (1)J(YC) coupling parameters provide a very sensitive measure of this NFC effect for the (Y(2)C(2))(4+) cluster. The crystal structural parameters of a previously reported metal carbide, Y(2)C(3) are directly compared to the (Y(2)C(2))(4+) cluster in the current metallofullerene study.

  1. Biological responses to immobilized microscale and nanoscale surface topographies.

    Science.gov (United States)

    Skoog, Shelby A; Kumar, Girish; Narayan, Roger J; Goering, Peter L

    2017-07-16

    Cellular responses are highly influenced by biochemical and biomechanical interactions with the extracellular matrix (ECM). Due to the impact of ECM architecture on cellular responses, significant research has been dedicated towards developing biomaterials that mimic the physiological environment for design of improved medical devices and tissue engineering scaffolds. Surface topographies with microscale and nanoscale features have demonstrated an effect on numerous cellular responses, including cell adhesion, migration, proliferation, gene expression, protein production, and differentiation; however, relationships between biological responses and surface topographies are difficult to establish due to differences in cell types and biomaterial surface properties. Therefore, it is important to optimize implant surface feature characteristics to elicit desirable biological responses for specific applications. The goal of this work was to review studies investigating the effects of microstructured and nanostructured biomaterials on in vitro biological responses through fabrication of microscale and nanoscale surface topographies, physico-chemical characterization of material surface properties, investigation of protein adsorption dynamics, and evaluation of cellular responses in specific biomedical applications. Published by Elsevier Inc.

  2. 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.

  3. Surfaces, scales, and synthesis: Scientific reasoning at the nanoscale

    Science.gov (United States)

    Bursten, Julia R.

    Philosophers interested in scientific methodology have focused largely on physics, biology, and cognitive science. They have paid considerably less attention to sciences such as chemistry and nanoscience, where not only are the subjects distinct, but the very aims differ: chemistry and nanoscience center around synthesis. Methods associated with synthesis do not fit well with description, explanation, and prediction that so dominate aims in philosophers paradigm sciences. In order to synthesize a substance or material, scientists need different kinds of information than they need to predict, explain, or describe. Consequently, they need different kinds of models and theories. Specifically, chemists need additional models of how reactions will proceed. In practice, this means chemists must model surface structure and behavior, because reactions occur on the surfaces of materials. Physics, and by extension much of philosophy of science, ignores the structure and behavior of surfaces, modeling surfaces only as boundary conditions with virtually no influence on material behavior. Such boundary conditions are not seen as part of the physical laws that govern material behavior, so little consideration has been given to their roles in improving scientists understanding of materials and aiding synthesis. But especially for theories that are used in synthesis, such neglect can lead to catastrophic modeling failures. In fact, as one moves down toward the nanoscale, the very concept of a material surface changes, with the consequence that nanomaterials behave differently than macroscopic materials made up of the same ele-ments. They conduct electricity differently, they appear differently colored, and they can play different roles in chemical reactions. This dissertation develops new philosophical tools to deal with these changes and give an account of theory and model use in the synthetic sciences. Particularly, it addresses the question of how models of materials at the

  4. Nanoscale simultaneous chemical and mechanical imaging via peak force infrared microscopy

    Science.gov (United States)

    Wang, Le; Wang, Haomin; Wagner, Martin; Yan, Yong; Jakob, Devon S.; Xu, Xiaoji G.

    2017-01-01

    Nondestructive chemical and mechanical measurements of materials with ~10-nm spatial resolution together with topography provide rich information on the compositions and organizations of heterogeneous materials and nanoscale objects. However, multimodal nanoscale correlations are difficult to achieve because of the limitation on spatial resolution of optical microscopy and constraints from instrumental complexities. We report a novel noninvasive spectroscopic scanning probe microscopy method—peak force infrared (PFIR) microscopy—that allows chemical imaging, collection of broadband infrared spectra, and mechanical mapping at a spatial resolution of 10 nm. In our technique, chemical absorption information is directly encoded in the withdraw curve of the peak force tapping cycle after illumination with synchronized infrared laser pulses in a simple apparatus. Nanoscale phase separation in block copolymers and inhomogeneity in CH3NH3PbBr3 perovskite crystals are studied with correlative infrared/mechanical nanoimaging. Furthermore, we show that the PFIR method is sensitive to the presence of surface phonon polaritons in boron nitride nanotubes. PFIR microscopy will provide a powerful analytical tool for explorations at the nanoscale across wide disciplines. PMID:28691096

  5. Ascertaining effects of nanoscale polymeric interfaces on competitive protein adsorption at the individual protein level.

    Science.gov (United States)

    Song, Sheng; Xie, Tian; Ravensbergen, Kristina; Hahm, Jong-in

    2016-02-14

    With the recent development of biomaterials and biodevices with reduced dimensionality, it is critical to comprehend protein adhesion processes to nanoscale solid surfaces, especially those occurring in a competitive adsorption environment. Complex sequences of adhesion events in competitive adsorption involving multicomponent protein systems have been extensively investigated, but our understanding is still limited primarily to macroscopic adhesion onto chemically simple surfaces. We examine the competitive adsorption behavior from a binary protein mixture containing bovine serum albumin and fibrinogen at the single protein level. We subsequently evaluate a series of adsorption and displacement processes occurring on both the macroscopic homopolymer and nanoscopic diblock copolymer surfaces, while systematically varying the protein concentration and incubation time. We identify the similarities and dissimilarities in competitive protein adsorption behavior between the two polymeric surfaces, the former presenting chemical uniformity at macroscale versus the latter exhibiting periodic nanointerfaces of chemically alternating polymeric segments. We then present our novel experimental finding of a large increase in the nanointerface-engaged residence time of the initially bound proteins and further explain the origin of this phenomenon manifested on nanoscale diblock copolymer surfaces. The outcomes of this study may provide timely insight into nanoscale competitive protein adsorption that is much needed in designing bioimplant and tissue engineering materials. In addition, the fundamental understanding gained from this study can be beneficial for the development of highly miniaturized biodevices and biomaterials fabricated by using nanoscale polymeric materials and interfaces.

  6. Nanoscale contact engineering for Silicon/Silicide nanowire devices

    Science.gov (United States)

    Lin, Yung-Chen

    Metal silicides have been used in silicon technology as contacts to achieve high device performance and desired device functions. The growth and applications of silicide materials have recently attracted increasing interest for nanoscale device applications. Nanoscale silicide materials have been demonstrated with various synthetic approaches. Solid state reaction wherein high quality silicides form through diffusion of metal atoms into silicon nano-templates and the subsequent phase transformation caught significant attention for the fabrication of nanoscale Si devices. Very interestingly, studies on the diffusion and phase transformation processes at nanoscale have indicated possible deviations from the bulk and the thin film system. Here we studied growth kinetics, electronic properties and device applications of nanoscale silicides formed through solid state reaction. We have grown single crystal PtSi nanowires and PtSi/Si/PtSi nanowire heterostructures through solid state reaction. TEM studies show that the heterostructures have atomically sharp interfaces free of defects. Electrical measurement of PtSi nanowires shows a low resistivity of ˜28.6 μΩ·cm and a high breakdown current density beyond 108 A/cm2. Furthermore, using single-crystal PtSi/Si/PtSi nanowire heterostructures with atomically clean interfaces, we have fabricated p-channel enhancement mode transistors with the best reported performance for intrinsic silicon nanowires to date. In our results, silicide can provide a clean and no Fermi level pinning interface and then silicide can form Ohmic-contact behavior by replacing the source/drain metal with PtSi. It has been proven by our experiment by contacting PtSi with intrinsic Si nanowires (no extrinsic doping) to achieve high performance p-channel device. By utilizing the same approach, single crystal MnSi nanowires and MnSi/Si/MnSi nanowire heterojunction with atomically sharp interfaces can also been grown. Electrical transport studies on Mn

  7. Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

    Directory of Open Access Journals (Sweden)

    Bruce L. Davis

    2011-12-01

    Full Text Available The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell and the phononic crystal lattice (defined by a supercell contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant, dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity.

  8. 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.

  9. Plant virus directed fabrication of nanoscale materials and devices

    Science.gov (United States)

    2015-03-26

    biological systems (Browne and Feringa , 2006; Korten et al., 2010; Stock et al., 2012). However, the development of such sophisticated assembly sys...nanorods and tubes for the display of functional peptides and residues. Biomacromolecules 14, 3123–3129. Browne, W.R., Feringa , B.L., 2006. Making

  10. Environmental, Health, and Safety Research Needs for Engineered Nanoscale Materials

    Science.gov (United States)

    2006-09-01

    Canady Forest Service (FS/USDA) Christopher Risbrudt Theodore Wegner Intelligence Technology Innovation Center (ITIC) Susan Durham International...particle agglomeration and settling. Some types of nanomaterials could become attached to dust, pollen , or other airborne particulates. Particles larger

  11. Engineered Nanoscale Materials and Derivative Products: Regulatory Challenges

    National Research Council Canada - National Science Library

    Schierow, Linda-Jo

    2008-01-01

    .... government has invested billions of dollars to ensure that American industry remains a global leader in the field, because the products of nanotechnology are seen to have great economic potential...

  12. Synthesis, Transfer, and Characterization of Nanoscale 2-Dimensional Materials

    Science.gov (United States)

    2015-09-01

    area code) 410-306-4953 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 iii Contents List of Figures iv Acknowledgments v 1...inset shows the corresponding CLSM image. b) SEM image of plates synthesized on Si. c) TEM image of hexagonal plate showing well- defined edges. d) EDS...with a Hitachi S4700 microscope. Transmission electron microscopy ( TEM ) was carried out using a JEOL 2100 microscope. 3. Results and Discussion 3.1

  13. Computational matter: evolving computational functions in nanoscale materials

    NARCIS (Netherlands)

    Broersma, Haitze J.; Miller, Julian F.; Nichele, Stefano; Adamatzky, Andrew

    2016-01-01

    Natural evolution has been manipulating the properties of proteins for billions of years. This ‘design process’ is completely different to conventional human design which assembles well-understood smaller parts in a highly principled way. In evolution-in-materio (EIM), researchers use evolutionary

  14. 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.

  15. MEMS & microsystems design, manufacture, and nanoscale engineering

    CERN Document Server

    Hsu, Tai-Ran

    2008-01-01

    A bestselling MEMS text...now better than ever. An engineering design approach to Microelectromechanical Systems, MEMS and Microsystems remains the only available text to cover both the electrical and the mechanical aspects of the technology. In the five years since the publication of the first edition, there have been significant changes in the science and technology of miniaturization, including microsystems technology and nanotechnology. In response to the increasing needs of engineers to acquire basic knowledge and experience in these areas, this popular text has been carefully updated, including an entirely new section on the introduction of nanoscale engineering. Following a brief introduction to the history and evolution of nanotechnology, the author covers the fundamentals in the engineering design of nanostructures, including fabrication techniques for producing nanoproducts, engineering design principles in molecular dynamics, and fluid flows and heat transmission in nanoscale substances.

  16. Anomalous electrical conductivity of nanoscale colloidal suspensions.

    Science.gov (United States)

    Chakraborty, Suman; Padhy, Sourav

    2008-10-28

    The electrical conductivity of colloidal suspensions containing nanoscale conducting particles is nontrivially related to the particle volume fraction and the electrical double layer thickness. Classical electrochemical models, however, tend to grossly overpredict the pertinent effective electrical conductivity values, as compared to those obtained under experimental conditions. We attempt to address this discrepancy by appealing to the complex interconnection between the aggregation kinetics of the nanoscale particles and the electrodynamics within the double layer. In particular, we model the consequent alterations in the effective electrophoretic mobility values of the suspension by addressing the fundamentals of agglomeration-deagglomeration mechanisms through the pertinent variations in the effective particulate dimensions, solid fractions, as well as the equivalent suspension viscosity. The consequent alterations in the electrical conductivity values provide a substantially improved prediction of the corresponding experimental findings and explain the apparent anomalous behavior predicted by the classical theoretical postulates.

  17. Nanoscale electron transport at the surface of a topological insulator

    Science.gov (United States)

    Bauer, Sebastian; Bobisch, Christian A.

    2016-01-01

    The use of three-dimensional topological insulators for disruptive technologies critically depends on the dissipationless transport of electrons at the surface, because of the suppression of backscattering at defects. However, in real devices, defects are unavoidable and scattering at angles other than 180° is allowed for such materials. Until now, this has been studied indirectly by bulk measurements and by the analysis of the local density of states in close vicinity to defect sites. Here, we directly measure the nanoscale voltage drop caused by the scattering at step edges, which occurs if a lateral current flows along a three-dimensional topological insulator. The experiments were performed using scanning tunnelling potentiometry for thin Bi2Se3 films. So far, the observed voltage drops are small because of large contributions of the bulk to the electronic transport. However, for the use of ideal topological insulating thin films in devices, these contributions would play a significant role. PMID:27098939

  18. Theory of quantum transport at nanoscale an introduction

    CERN Document Server

    Ryndyk, Dmitry A

    2016-01-01

    This book is an introduction to a rapidly developing field of modern theoretical physics – the theory of quantum transport at nanoscale. The theoretical methods considered in the book are in the basis of our understanding of charge, spin and heat transport in nanostructures and nanostructured materials and are widely used in nanoelectronics, molecular electronics, spin-dependent electronics (spintronics) and bio-electronics. The book is based on lectures for graduate and post-graduate students at the University of Regensburg and the Technische Universität Dresden (TU Dresden). The first part is devoted to the basic concepts of quantum transport: Landauer-Büttiker method and matrix Green function formalism for coherent transport, Tunneling (Transfer) Hamiltonian and master equation methods for tunneling, Coulomb blockade, vibrons and polarons. The results in this part are obtained as possible without sophisticated techniques, such as nonequilibrium Green functions, which are considered in detail in the...

  19. The physics of semiconductor microcavities. From fundamentals to nanoscale devices

    Energy Technology Data Exchange (ETDEWEB)

    Deveaud, B. (ed.) [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland). Inst. of Quantum Electronics and Photonics

    2007-07-01

    Electron and photon confinement in semiconductor nanostructures is one of the most active areas in solid state research. Written by leading experts in solid state physics, this book provides both a comprehensive review as well as an excellent introduction to fundamental and applied aspects of light-matter coupling in microcavities. Topics covered include parametric amplification and polariton liquids, quantum fluid and non-linear dynamical effects and parametric instabilities, polariton squeezing. Bose-Einstein condensation of microcavity polaritons, spin dynamics of exciton-polaritons, polariton correlation produced by parametric scattering, progress in III-nitride distributed Bragg reflectors using AlInN/GaN materials, high efficiency planar MCLEDs, exciton-polaritons and nanoscale cavities in photonic crystals, and MBE growth of high finesse microcavities. (orig.)

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

    DEFF Research Database (Denmark)

    Bork, Jakob

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

  1. Method and system for nanoscale plasma processing of objects

    Science.gov (United States)

    Oehrlein, Gottlieb S [Clarksville, MD; Hua, Xuefeng [Hyattsville, MD; Stolz, Christian [Baden-Wuerttemberg, DE

    2008-12-30

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

  2. Study on hydrothermal synthesis dynamics of nanoscale xonotlite fibers

    Science.gov (United States)

    Liu, F.; Chen, S.; Lin, Q.; Wang, X. D.; Cao, J. X.

    2018-01-01

    The xonotlite crystals were synthesized via the hydrothermal synthesis manner from CaO and SiO2 as the raw materials with their Si/Ca molar ratio of 1.0. Hydrothermal synthesis dynamics of nanoscale xonotlite fibers was explored by masterly measuring the electrical conductivities and the calcium concentrations of product slurries synthesized at various reaction temperature in this paper. The results indicated that the calculated values of the products’ quality at various reaction temperatures were consistent with the measured values. Based on chemical reaction kinetic, using fourth-order Runge-Kutta method, spline interpolation and least-squares fitting method, the dynamic relationship of xonotlite fibers synthesized via hydrothermal synthesis process is of -{dc}A/{dt}={kc}A4/5.

  3. Hydrogen Bond Nanoscale Networks Showing Switchable Transport Performance

    Science.gov (United States)

    Long, Yong; Hui, Jun-Feng; Wang, Peng-Peng; Xiang, Guo-Lei; Xu, Biao; Hu, Shi; Zhu, Wan-Cheng; Lü, Xing-Qiang; Zhuang, Jing; Wang, Xun

    2012-08-01

    Hydrogen bond is a typical noncovalent bond with its strength only one-tenth of a general covalent bond. Because of its easiness to fracture and re-formation, materials based on hydrogen bonds can enable a reversible behavior in their assembly and other properties, which supplies advantages in fabrication and recyclability. In this paper, hydrogen bond nanoscale networks have been utilized to separate water and oil in macroscale. This is realized upon using nanowire macro-membranes with pore sizes ~tens of nanometers, which can form hydrogen bonds with the water molecules on the surfaces. It is also found that the gradual replacement of the water by ethanol molecules can endow this film tunable transport properties. It is proposed that a hydrogen bond network in the membrane is responsible for this switching effect. Significant application potential is demonstrated by the successful separation of oil and water, especially in the emulsion forms.

  4. Buckling instabilities of nanoscale polymer films and colloidal particle layers

    Science.gov (United States)

    Gurmessa, Bekele Jemama

    Nanoscale polymer films have numerous potential applications such as protective coatings, flexible electronics, energy harvesting devices, and drug delivery systems. For realization of these potential applications, the mechanical properties of these materials and the underlying physics need to be understood. This dissertation focuses on understanding the responses of nanoscale films to mechanical deformations. In this regard, an elastic instability was exploited to locally bend and impart a local tensile stress in a nanoscale polystyrene film, and directly measure the resulting residual stress caused by the bending. Our results indicate that the onset of permanent deformation for thin polystyrene films is an order of magnitude smaller than what has been reported for the bulk value. In addition, not only is the onset of failure strain found to be small but also it increases with increased confinement. Using similar processing techniques, the yield strain of a more complex material---poly(styrene-b-divinylpyridine)---was studied. Similar to the polystyrene films, failure in polystyrene-b-poly(2-vinylpyridine) is also initiated at extremely low strain and is influenced by thin film confinement effects. In addition, we have demonstrated that internal nanostructure of self-assembled polystyrene-b-poly(2-vinylpyridine) affects the onset of failure strain. Having introduced an idealized heterogeneity to a sample through ultraviolet/ozone treatment, we have created samples ranging from continuous thin films to sets of isolated plates. We demonstrated that, when subjected to mechanical deformation, the unbounded plates form isotropic undulations that persist even beyond high strain. In contrast, isolated plates undergo non-isotropic undulations in the range of high strains. The non-isotropic undulation shape has been described through a simple numerical modeling subjected to controlled boundary conditions. The agreement between experiment and numerical modeling is

  5. Nanoscale molecularly imprinted polymers and method thereof

    Science.gov (United States)

    Hart, Bradley R [Brentwood, CA; Talley, Chad E [Brentwood, CA

    2008-06-10

    Nanoscale molecularly imprinted polymers (MIP) having polymer features wherein the size, shape and position are predetermined can be fabricated using an xy piezo stage mounted on an inverted microscope and a laser. Using an AMF controller, a solution containing polymer precursors and a photo initiator are positioned on the xy piezo and hit with a laser beam. The thickness of the polymeric features can be varied from a few nanometers to over a micron.

  6. 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.

  7. 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.

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

    Science.gov (United States)

    Reed, Mark

    2009-10-01

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

  9. 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.

  10. Nanoscale piezoelectric vibration energy harvester design

    Directory of Open Access Journals (Sweden)

    Hamid Reza Foruzande

    2017-09-01

    Full Text Available Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton’s principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

  11. 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.

  12. Static electric field enhancement in nanoscale structures

    Science.gov (United States)

    Lepetit, Bruno; Lemoine, Didier; Márquez-Mijares, Maykel

    2016-08-01

    We study the effect of local atomic- and nano-scale protrusions on field emission and, in particular, on the local field enhancement which plays a key role as known from the Fowler-Nordheim model of electronic emission. We study atomic size defects which consist of right angle steps forming an infinite length staircase on a tungsten surface. This structure is embedded in a 1 GV/m ambient electrostatic field. We perform calculations based upon density functional theory in order to characterize the total and induced electronic densities as well as the local electrostatic fields taking into account the detailed atomic structure of the metal. We show how the results must be processed to become comparable with those of a simple homogeneous tungsten sheet electrostatic model. We also describe an innovative procedure to extrapolate our results to nanoscale defects of larger sizes, which relies on the microscopic findings to guide, tune, and improve the homogeneous metal model, thus gaining predictive power. Furthermore, we evidence analytical power laws for the field enhancement characterization. The main physics-wise outcome of this analysis is that limited field enhancement is to be expected from atomic- and nano-scale defects.

  13. Visualizing nanoscale phase morphology for understanding photovoltaic performance of PTB7: PC71BM solar cell

    Science.gov (United States)

    Supasai, Thidarat; Amornkitbamrung, Vittaya; Thanachayanont, Chanchana; Tang, I.-Ming; Sutthibutpong, Thana; Rujisamphan, Nopporn

    2017-11-01

    Visualizing and controlling the phase separation of the donor and acceptor domains in organic bulk-hetero-junction (BHJ) solar devices made with poly([4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethyl-hexyl)carbon-yl]thieno[3,4-bthiophenediyl]) (PTB7) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) are needed to achieve high power conversion efficiency (PCE). Traditional bright-field (BF) imaging, especially of polymeric materials, produces images of poor contrast when done at the nanoscale level. Clear nanoscale morphologies of the PTB7:PC71BM blends prepared with different 1,8-diiodooctane (DIO) concentrations were seen when using the energy-filtered transmission electron microscopy (EFTEM). The electron energy loss (EELS) spectra of the pure PTB7 and PC71BM samples are centered at 22.7 eV and 24.5 eV, respectively. Using the electrons whose energy losses are in the range of 16-30 eV, detail information of the phase morphology at the nanoscale was obtained. Correlations between the improvement in the photovoltaic performances and the increased electron mobility were seen. These correlations are discussed in terms of the changes (at the nanoscale level) in blending phase morphology when different DIO concentrations are added.

  14. Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields

    Science.gov (United States)

    Zhu, Yi; Chen, Frank; Park, Joonkyu; Sasikumar, Kiran; Hu, Bin; Damodaran, Anoop R.; Jung, Il Woong; Highland, Matthew J.; Cai, Zhonghou; Tung, I.-Cheng; Walko, Donald A.; Freeland, John W.; Martin, Lane W.; Sankaranarayanan, Subramanian K. R. S.; Evans, Paul G.; Lindenberg, Aaron M.; Wen, Haidan

    2017-11-01

    Nanoscale phonon transport is a key process that governs thermal conduction in a wide range of materials and devices. Creating controlled phonon populations by resonant excitation at terahertz (THz) frequencies can drastically change the characteristics of nanoscale thermal transport and allow a direct real-space characterization of phonon mean-free paths. Using metamaterial-enhanced terahertz excitation, we tailored a phononic excitation by selectively populating low-frequency phonons within a nanoscale volume in a ferroelectric BaTi O3 thin film. Real-space time-resolved x-ray diffraction microscopy following THz excitation reveals ballistic phonon transport over a distance of hundreds of nm, two orders of magnitude longer than the averaged phonon mean-free path in BaTi O3 . On longer length scales, diffusive phonon transport dominates the recovery of the transient strain response, largely due to heat conduction into the substrate. The measured real-space phonon transport can be directly compared with the phonon mean-free path as predicted by molecular dynamics modeling. This time-resolved real-space visualization of THz-matter interactions opens up opportunities to engineer and image nanoscale transient structural states with new functionalities.

  15. Effect of nanoscale particles incorporation on microhardness of polymers for oral prosthesis

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho Goiato

    2016-01-01

    Full Text Available Objectives: This study aimed to evaluate the influence of the incorporation of pigments on surface hardness of four acrylic resins subjected to thermocycling and analyze their elemental composition using energy dispersive X-ray spectroscopy (EDS. Materials and Methods: Twenty-one discs of each resin were fabricated, whereas seven had no additive, seven had 3% of nanoscale pigments and last seven had 10% of them. The percentage was obtained by measuring the total weight of each resin disc. Besides, seven discs composed by only nanoscale pigments were also fabricated, totalizing 91 discs. The pigment was weighed by using an analytical balance (BEL Analytical Equipment, SP, Brazil. The surface hardness was measured through a hardness tester machine before and after thermocycling (5-55°C, for 2000 cycles. Data were analyzed by ANOVA and Tukey′s test (P < 0.05. The chemical composition of the discs composed only by nanoscale pigments was analyzed with EDS test. Results: Hardness of all resins decreased after thermocycling. The lowest values were observed on the discs with 3% of nanoscale pigments and discs fabricated only with them. EDS showed the presence of titanium dioxide. Conclusion: Discs with 7% of pigments (after thermocycling showed higher hardness values.

  16. Quantitative nanoscale electrostatics of viruses.

    Science.gov (United States)

    Hernando-Pérez, M; Cartagena-Rivera, A X; Lošdorfer Božič, A; Carrillo, P J P; San Martín, C; Mateu, M G; Raman, A; Podgornik, R; de Pablo, P J

    2015-11-07

    Electrostatics is one of the fundamental driving forces of the interaction between biomolecules in solution. In particular, the recognition events between viruses and host cells are dominated by both specific and non-specific interactions and the electric charge of viral particles determines the electrostatic force component of the latter. Here we probe the charge of individual viruses in liquid milieu by measuring the electrostatic force between a viral particle and the Atomic Force Microscope tip. The force spectroscopy data of co-adsorbed ϕ29 bacteriophage proheads and mature virions, adenovirus and minute virus of mice capsids is utilized for obtaining the corresponding density of charge for each virus. The systematic differences of the density of charge between the viral particles are consistent with the theoretical predictions obtained from X-ray structural data. Our results show that the density of charge is a distinguishing characteristic of each virus, depending crucially on the nature of the viral capsid and the presence/absence of the genetic material.

  17. Interfacial Symmetry Control of Emergent Ferromagnetism at the Nanoscale.

    Science.gov (United States)

    Grutter, A J; Vailionis, A; Borchers, J A; Kirby, B J; Flint, C L; He, C; Arenholz, E; Suzuki, Y

    2016-09-14

    The emergence of complex new ground states at interfaces has been identified as one of the most promising routes to highly tunable nanoscale materials. Despite recent progress, isolating and controlling the underlying mechanisms behind these emergent properties remains among the most challenging materials physics problems to date. In particular, generating ferromagnetism localized at the interface of two nonferromagnetic materials is of fundamental and technological interest. Moreover, the ability to turn the ferromagnetism on and off would shed light on the origin of such emergent phenomena and is promising for spintronic applications. We demonstrate that ferromagnetism confined within one unit cell at the interface of CaRuO3 and CaMnO3 can be switched on and off by changing the symmetry of the oxygen octahedra connectivity at the boundary. Interfaces that are symmetry-matched across the boundary exhibit interfacial CaMnO3 ferromagnetism while the ferromagnetism at symmetry-mismatched interfaces is suppressed. We attribute the suppression of ferromagnetic order to a reduction in charge transfer at symmetry-mismatched interfaces, where frustrated bonding weakens the orbital overlap. Thus, interfacial symmetry is a new route to control emergent ferromagnetism in materials such as CaMnO3 that exhibit antiferromagnetism in bulk form.

  18. Uncovering new thermal and mechanical behavior at the nanoscale using coherent extreme ultraviolet light

    Science.gov (United States)

    Hoogeboom-Pot, Kathleen Marie

    Tremendous recent progress in nanofabrication capabilities has made high-quality single-atomic layers and nanostructures with dimensions well below 50 nm commonplace, enabling unprecedented access to materials at the nanoscale. However, tools and techniques capable of characterizing the properties and function of nanosystems are still quite limited, leaving much of the fundamental physics that dominates material behavior in the deep nano-regime still unknown. Further understanding gained by studying nanoscale materials is critical both to fundamental science and to continued technological development. This thesis applies coherent extreme ultraviolet (EUV) light from tabletop high harmonic generation to study nanoscale systems on their intrinsic length and time scales (nanometers and femtoseconds, and above), specifically following thermal transport and acoustic dynamics. These studies have shown where and how nanostructured material properties can be quite different from their bulk counterparts. This has in turn allowed us to develop new theoretical descriptions to guide further work. By observing heat dissipation from the smallest nanostructure heat sources measured to date (at 20 nm in lateral size), this work uncovers a previously unobserved and unpredicted nanoscale thermal transport regime where both size and spacing of heat sources play a role in determining the heat dissipation effciency. Surprisingly, this shows that nanoscale heat sources can cool more quickly when spaced close together than when far apart. This discovery is significant to the engineering of thermal management in nanoscale systems and devices while also revealing new insight into the fundamental nature of thermal transport. Furthermore, we harness this new regime to demonstrate the first experimental measurement of the differential contributions of phonons with different mean free paths to thermal conductivity, down to mean free paths as short as 14 nm for the first time. The same

  19. Biomolecular Programming of Discrete Nanomaterials for Sensors, Templates and Mimics of Natural Nanoscale Assemblies

    Science.gov (United States)

    2016-10-17

    AFRL-AFOSR-VA-TR-2016-0343 BIOMOLECULAR PROGRAMMING OF DISCRETE NANOMATERIALS FOR SENSORS, TEMPLATES AND MIMICS OF NATURAL NANOSCALE ASSEMBLIES...Performance 3. DATES COVERED (From - To) 01 Jun 2011 to 31 May 2016 4. TITLE AND SUBTITLE BIOMOLECULAR PROGRAMMING OF DISCRETE NANOMATERIALS FOR SENSORS...term use are needed; hence our interest in stabilized but responsive biomolecular materials and conjugates between 2011 and 2016. In terms of melanin

  20. Atomistic investigation of the wear of nanoscale diamond cutting tools shaped by focused ion beam

    OpenAIRE

    Tong, Zhen; Jiang, Xiang; Bai, Qingshun; Blunt, Liam; Luo, Xichun

    2016-01-01

    In recent years, micro/nanoscale diamond cutting tools shaped by focused ion beam (FIB) has been developed to the deterministic fabrication of micro/nano-structures owing to its unprecedented merits of high throughput, one-step, and highly flexible precision capabilities. However, the exposure of a diamond tool to FIB will result in the implantation of ion source material and the irradiation damage in cutting edges, and thus affect the tool life. In this work, molecular dynamics (MD) simulati...

  1. Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopy

    DEFF Research Database (Denmark)

    Gilbert, B.; Frandsen, Cathrine; Maxey, E.R.

    2009-01-01

    -gap determination in bulk and nanoscale itinerant electron semiconductors such as CdS and ZnO, but this approach has not been established for materials such as iron oxides that possess band-edge electronic structure dominated by electron correlations. We performed soft x-ray spectroscopy at the oxygen K...... of phase-pure hematite nanoparticles, we find that there is no evidence for size-driven change in the band gap of hematite nanoparticles down to around 8 nm....

  2. Atomic layer deposition: an enabling technology for the growth of functional nanoscale semiconductors

    Science.gov (United States)

    Biyikli, Necmi; Haider, Ali

    2017-09-01

    In this paper, we present the progress in the growth of nanoscale semiconductors grown via atomic layer deposition (ALD). After the adoption by semiconductor chip industry, ALD became a widespread tool to grow functional films and conformal ultra-thin coatings for various applications. Based on self-limiting and ligand-exchange-based surface reactions, ALD enabled the low-temperature growth of nanoscale dielectric, metal, and semiconductor materials. Being able to deposit wafer-scale uniform semiconductor films at relatively low-temperatures, with sub-monolayer thickness control and ultimate conformality, makes ALD attractive for semiconductor device applications. Towards this end, precursors and low-temperature growth recipes are developed to deposit crystalline thin films for compound and elemental semiconductors. Conventional thermal ALD as well as plasma-assisted and radical-enhanced techniques have been exploited to achieve device-compatible film quality. Metal-oxides, III-nitrides, sulfides, and selenides are among the most popular semiconductor material families studied via ALD technology. Besides thin films, ALD can grow nanostructured semiconductors as well using either template-assisted growth methods or bottom-up controlled nucleation mechanisms. Among the demonstrated semiconductor nanostructures are nanoparticles, nano/quantum-dots, nanowires, nanotubes, nanofibers, nanopillars, hollow and core-shell versions of the afore-mentioned nanostructures, and 2D materials including transition metal dichalcogenides and graphene. ALD-grown nanoscale semiconductor materials find applications in a vast amount of applications including functional coatings, catalysis and photocatalysis, renewable energy conversion and storage, chemical sensing, opto-electronics, and flexible electronics. In this review, we give an overview of the current state-of-the-art in ALD-based nanoscale semiconductor research including the already demonstrated and future applications.

  3. Ferroelectric crystals for photonic applications including nanoscale fabrication and characterization techniques

    CERN Document Server

    Grilli, Simonetta

    2008-01-01

    This book deals with the latest achievements in the field of ferroelectric domain engineering and characterization at micron- and nano-scale dimensions and periods. The book collects the results obtained in the last years by world scientific leaders in the field, thus providing a valid and unique overview of the state of the art and also a view to future applications of those engineered materials in the field of photonics.

  4. Crystallization of high-strength nano-scale leucite glass-ceramics.

    Science.gov (United States)

    Theocharopoulos, A; Chen, X; Wilson, R M; Hill, R; Cattell, M J

    2013-11-01

    Fine-grained, high strength, translucent leucite dental glass-ceramics are synthesized via controlled crystallization of finely milled glass powders. The objectives of this study were to utilize high speed planetary milling of an aluminosilicate glass for controlled surface crystallization of nano-scale leucite glass-ceramics and to test the biaxial flexural strength. An aluminosilicate glass was synthesized, attritor or planetary milled and heat-treated. Glasses and glass-ceramics were characterized using particle size analysis, X-ray diffraction and scanning electron microscopy. Experimental (fine and nanoscale) and commercial (Ceramco-3, IPS Empress Esthetic) leucite glass-ceramics were tested using the biaxial flexural strength (BFS) test. Gaussian and Weibull statistics were applied. Experimental planetary milled glass-ceramics showed an increased leucite crystal number and nano-scale median crystal sizes (0.048-0.055 μm(2)) as a result of glass particle size reduction and heat treatments. Experimental materials had significantly (p0.05) strength difference. All other groups' mean BFS and characteristic strengths were found to be significantly different (pglass-ceramics with high flexural strength. These materials may help to reduce problems associated with brittle fracture of all-ceramic restorations and give reduced enamel wear. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. Grain engineering: How nanoscale inhomogeneities can control charge collection in solar cells

    Energy Technology Data Exchange (ETDEWEB)

    West, Bradley M.; Stuckelberger, Michael; Guthrey, Harvey; Chen, Lei; Lai, Barry; Maser, Jörg; Rose, Volker; Shafarman, William; Al-Jassim, Mowafak; Bertoni, Mariana I.

    2017-02-01

    Statistical and correlative analysis are increasingly important in the design and study of new materials, from semiconductors to metals. Non-destructive measurement techniques, with high spatial resolution, capable of correlating composition and/or structure with device properties, are few and far between. For the case of polycrystalline and inhomogeneous materials, the added challenge is that nanoscale resolution is in general not compatible with the large sampling areas necessary to have a statistical representation of the specimen under study. For the study of grain cores and grain boundaries in polycrystalline solar absorbers this is of particular importance since their dissimilar behavior and variability throughout the samples makes it difficult to draw conclusions and ultimately optimize the material. In this study, we present a nanoscale in-operando approach based on the multimodal utilization of synchrotron nano x-ray fluorescence and x-ray beam induced current collected for grain core and grain boundary areas and correlated pixel-by-pixel in fully operational Cu(In(1-x)Gax)Se2Cu(In(1-x)Gax)Se2 solar cells. We observe that low gallium cells have grain boundaries that over perform compared to the grain cores and high gallium cells have boundaries that under perform. These results demonstrate how nanoscale correlative X-ray microscopy can guide research pathways towards grain engineering low cost, high efficiency solar cells.

  6. Coordination modulation induced synthesis of nanoscale Eu(1-x)Tb(x)-metal-organic frameworks for luminescent thin films.

    Science.gov (United States)

    Guo, Hailing; Zhu, Yongzhong; Qiu, Shilun; Lercher, Johannes A; Zhang, Hongjie

    2010-10-01

    Strategies for synthesizing of nanoscale single or bimetallic lanthanide metal-organic framework (MOF) materials and their transformation into Eu(1-x)Tb(x)-MOF thin films are reported. The thin films prepared via spin coating deposition method are smooth, dense and mechanically stable. They also exhibit marked luminescent properties and efficient Tb(3+)-to-Eu(3+) energy transferability.

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

    KAUST Repository

    Wang, Xianbin

    2015-01-22

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

  8. 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.

  9. EDITORIAL: Light Control at the Nanoscale

    Science.gov (United States)

    Kral, Petr; Shapiro, Moshe

    2007-06-01

    It is customary to denote as 'nano-systems' entities whose size varies between 1 and 100 nm. Such systems span an immense variety of structures, ranging from large molecules, quantum dots, and nanowires, to viruses. Their existence is based on, and accompanied by, an amazing abundance of phenomena, depending on a huge number of parameters, all of which can in principle be used for nanoscale control. One of the most potent means of controlling nano-systems is light: it can serve as a tool for the addressing, preparation, stabilization and excitation of nano-systems. Design of light control scenarios is based on the laser techniques of coherent and optimal control at wavelengths and time sequencing most appropriate to the nano-systems, or on more traditional, incoherent forms of light-matter interactions. This special issue of Journal of Physics B: Atomic, Molecular and Optical Physics (J. Phys. B) devoted to the subject of light control at the nanoscale contains a collection of articles that cover several key areas in this fast-growing field. These include: preparation and manipulation of nano-systems by light, nanoscale plasmonics and spintronics, Bose-Einstein condensation and excitation of novel molecular and crystalline systems. We have grouped the papers according to these general areas. The guest editors gratefully acknowledge the help of the staff of J. Phys. B, especially that of Alice Malhador from the editorial team, and Adrian Corrigan from production, in preparing this issue, and Professor Jan-Michel Rost, the Editor-in-Chief, for his support of this project.

  10. Resist requirements and limitations for nanoscale electron-beam patterning.

    Energy Technology Data Exchange (ETDEWEB)

    Liddle, J. A.; Gallatin, G. M.; Ocola, L. E.; Experimental Facilities Division (APS); LBNL; IBM T.J. Watson Research Center

    2003-01-01

    Electron beam lithography still represents the most effective way to pattern materials at the nanoscale, especially in the case of structures, which are not indefinitely repeating a simple motif. The success of e-beam lithography depends on the availability of suitable resists. There is a substantial variety of resist materials, from PMMA to calixarenes, to choose from to achieve high resolution in electron-beam lithography. However, these materials suffer from the limitation of poor sensitivity and poor contrast. In both direct-write and projection e-beam systems the maximum beam current for a given resolution is limited by space-charge effects. In order to make the most efficient use of the available current, the resist must be as sensitive as possible. This leads, naturally, to the use of chemically amplified (CA) systems. Unfortunately, in the quest for ever smaller feature sizes and higher throughputs, even chemically amplified materials are limited: ultimately, sensitivity and resolution are not independent. Current resists already operate in the regime of < 1 electron/nm2. In this situation detailed models are the only way to understand material performance and limits. Resist requirements, including sensitivity, etch selectivity, environmental stability, outgassing, and line-edge roughness as they pertain to, high-voltage (100 kV) direct write and projection electron-beam exposure systems are described. Experimental results obtained on CA resists in the SCALPEL exposure system are presented and the fundamental sensitivity limits of CA and conventional materials in terms of shot-noise and resolution limits in terms of electron-beam solid interactions are discussed.

  11. Inelastic transport theory for nanoscale systems

    DEFF Research Database (Denmark)

    Frederiksen, Thomas

    2007-01-01

    This thesis describes theoretical and numerical investigations of inelastic scat- tering and energy dissipation in electron transport through nanoscale sys- tems. A computational scheme, based on a combination of density functional theory (DFT) and nonequilibrium Green’s functions (NEGF), has been...... the conductance. The methods have been applied to a number of specific systems, includ- ing monatomic gold chains, atomic point contacts, and metal-molecule-metal configurations. These studies have clarified the inelastic effects in the elec- tron transport and characterized the vibrational modes that couple...

  12. Nanoscale analysis of biofunctional molecules and components.

    Science.gov (United States)

    Metzger, W; Oberringer, M; Hu, J; Li, M Q; Hartmann, U

    2004-05-01

    In basic medical research, as well as in concrete clinical applications, the nanoscale analysis of biofunctional units is of strongly increasing relevance. Dedicated investigations on molecules, molecular composites or functional units can efficiently be performed ex or in situ by scanning probe methods and, namely, by scanning force microscopy. In the following investigations, the folding behavior of DNA is presented as an example of basic research in medicine. In contrast, the investigation of bioadsorption phenomena in systems on which apheresis therapies are based provides a real contribution to applied medicine.

  13. 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...

  14. Nanoscale growth twins in sputtered metal films

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Amit [Los Alamos National Laboratory; Anderoglu, Osman [Los Alamos National Laboratory; Hoagland, Richard G [Los Alamos National Laboratory; Zhang, X [TEXAS A& M

    2008-01-01

    We review recent studies on the mechanical properties of sputtered Cu and 330 stainless steel films with {l_brace}1 1 1{r_brace} nanoscale growth twins preferentially oriented perpendicular to growth direction. The mechanisms of formation of growth twins during sputtering and the deformation mechanisms that enable usually high strengths in nanotwinned structures are highlighted. Growth twins in sputtered films possess good thermal stability at elevated temperature, providing an approach to extend the application of high strength nanostructured metals to higher temperatures.

  15. Approaching the downsizing limit of silicon for surface-controlled lithium storage.

    Science.gov (United States)

    Wang, Bin; Li, Xianglong; Luo, Bin; Hao, Long; Zhou, Min; Zhang, Xinghao; Fan, Zhuangjun; Zhi, Linjie

    2015-03-04

    Graphene-sheet-supported uniform ultrasmall (≈3 nm) silicon quantum dots have been successfully synthesized by a simple and effective self-assembly strategy, exhibiting unprecedented fast, surface-controlled lithium-storage behavior and outstanding lithium-storage properties including extraordinary rate capability and remarkable cycling stability, attributable to the intrinsic role of approaching the downsizing limit of silicon. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Adaptive Dynamic Surface Control is designed for Twin Rotor unmanned helicopter in three-dimensional space

    Directory of Open Access Journals (Sweden)

    Amir Reza Moadeli

    2016-01-01

    Full Text Available In this paper, the system control design problem twin rotors helicopters Unmanned Aerial Vehicles (UAV in three dimensional space Without uncertainty based on the dynamic adaptive control is studied. the adaptive Dynamic surface control approach complexity explosion problem in non-linear control step back or backstepping method [45] using the First-order filters removed. The first helicopter dynamic equations and functions are examined. Then, the Dynamic surface control techniques by compare non-linear control technique back stepping [45] is checked and the system is simulation by both techniques adaptive Dynamic surface control and nonlinear control back stepping method. The proposed adaptive dynamics surface nonlinear control method approach is able to guarantees that all the signals in the closed-loop system are asymptotically stable for all initial conditions and you can also choose appropriate design parameters of the system output converges to a small neighborhood of origin ensured . Finally, simulation results are presented, showing the effectiveness of control methods are given.

  17. 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

    2014-12-19

    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 sp(2) 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.

  18. Convex Lens-Induced Nanoscale Templating

    Science.gov (United States)

    Berard, Daniel; Michaud, Francois; McFaul, Christopher; Mahsid, Sara; Reisner, Walter; Leslie, Sabrina

    2014-03-01

    We demonstrate a new platform, ``Convex Lens-Induced Nanoscale Templating'' (CLINT), for dynamic manipulation and trapping of single DNA molecules. In the CLINT technique, the curved surface of a convex lens is used to deform a flexible coverslip above a substrate containing embedded nanotopography, creating a nanoscale gap that can be adjusted during an experiment to confine molecules within the embedded nanostructures. Critically, CLINT has the capability of actively transforming a macroscale flow-cell into a nanofluidic device without need for high-temperature direct bonding, leading to ease of sample loading and greater accessibility of the surface. Moreover, as DNA molecules present in the gap will be driven into the embedded topography from above, CLINT eliminates the need for the high pressures or electric fields necessitated by direct bonded nanofluidic devices for loading DNA in the confined structures. To demonstrate the versatility of CLINT, we confine DNA to nanogroove structures, demonstrating DNA nanochannel-based stretching. Using ionic strengths that are in line with typical biological buffers, we have successfully extended DNA in sub 30nm nanochannels, achieving high stretching (90%) that is in good agreement with Odijk deflection theory.

  19. Probing Nanoscale Thermal Transport in Surfactant Solutions

    Science.gov (United States)

    Cao, Fangyu; Liu, Ying; Xu, Jiajun; He, Yadong; Hammouda, B.; Qiao, Rui; Yang, Bao

    2015-11-01

    Surfactant solutions typically feature tunable nanoscale, internal structures. Although rarely utilized, they can be a powerful platform for probing thermal transport in nanoscale domains and across interfaces with nanometer-size radius. Here, we examine the structure and thermal transport in solution of AOT (Dioctyl sodium sulfosuccinate) in n-octane liquids using small-angle neutron scattering, thermal conductivity measurements, and molecular dynamics simulations. We report the first experimental observation of a minimum thermal conductivity occurring at the critical micelle concentration (CMC): the thermal conductivity of the surfactant solution decreases as AOT is added till the onset of micellization but increases as more AOT is added. The decrease of thermal conductivity with AOT loading in solutions in which AOT molecules are dispersed as monomers suggests that even the interfaces between individual oleophobic headgroup of AOT molecules and their surrounding non-polar octane molecules can hinder heat transfer. The increase of thermal conductivity with AOT loading after the onset of micellization indicates that the thermal transport in the core of AOT micelles and across the surfactant-oil interfaces, both of which span only a few nanometers, are efficient.

  20. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  1. Frontier in nanoscale flows fractional calculus and analytical methods

    CERN Document Server

    Lewis, Roland; Liu, Hong-yan

    2014-01-01

    This ebook covers the basic properties of nanoscale flows, and various analytical and numerical methods for nanoscale flows and environmental flows. This ebook is a good reference not only for audience of the journal, but also for various communities in mathematics, nanotechnology and environmental science.

  2. Performance and properties of nanoscale calcium peroxide for toluene removal.

    Science.gov (United States)

    Qian, Yajie; Zhou, Xuefei; Zhang, Yalei; Zhang, Weixian; Chen, Jiabin

    2013-04-01

    Due to the large diameter and small surface, the contaminant degradation by conventional calcium peroxide (CaO2) is slow with high dosage required. The aggregation of conventional CaO2 also makes it difficult to operate. Nanoscale CaO2 was therefore synthesized and applied to remove toluene in this study. Prepared from nanoscale Ca(OH)2 and H2O2 in the ratio of 1:7, the finely dispersed nanoscale CaO2 particles were confirmed by the scanning electron microscope to be in the range of 100-200nm in size. Compared to their non nanoscale counterparts, the synthesized nanoscale CaO2 demonstrated a superior performance in the degradation of toluene, which could be eliminated in 3d at pH 6. The oxidation products of toluene were analyzed to include benzyl alcohol, benzaldehyde and three cresol isomers. With the addition of 2-propanol, hydroxyl radicals were indicated as the main reactive oxygen species in the oxidation of toluene by nanoscale CaO2. Superoxide radicals were also investigated as the marker of nanoscale CaO2 in the solution. Our study thus provides an important insight into the application of nanoscale CaO2 in the removal of toluene contaminants, which is significant, especially for controlling the petroleum contaminations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Method to determine thermal profiles of nanoscale circuitry

    Science.gov (United States)

    Zettl, Alexander K; Begtrup, Gavi E

    2013-04-30

    A platform that can measure the thermal profiles of devices with nanoscale resolution has been developed. The system measures the local temperature by using an array of nanoscale thermometers. This process can be observed in real time using a high resolution imagining technique such as electron microscopy. The platform can operate at extremely high temperatures.

  4. An open-source platform to study uniaxial stress effects on nanoscale devices.

    Science.gov (United States)

    Signorello, G; Schraff, M; Zellekens, P; Drechsler, U; Bürge, M; Steinauer, H R; Heller, R; Tschudy, M; Riel, H

    2017-05-01

    We present an automatic measurement platform that enables the characterization of nanodevices by electrical transport and optical spectroscopy as a function of the uniaxial stress. We provide insights into and detailed descriptions of the mechanical device, the substrate design and fabrication, and the instrument control software, which is provided under open-source license. The capability of the platform is demonstrated by characterizing the piezo-resistance of an InAs nanowire device using a combination of electrical transport and Raman spectroscopy. The advantages of this measurement platform are highlighted by comparison with state-of-the-art piezo-resistance measurements in InAs nanowires. We envision that the systematic application of this methodology will provide new insights into the physics of nanoscale devices and novel materials for electronics, and thus contribute to the assessment of the potential of strain as a technology booster for nanoscale electronics.

  5. Probing Stochastic Nano-Scale Inelastic Events in Stressed Amorphous Metal

    Science.gov (United States)

    Yang, Y.; Fu, X. L.; Wang, S.; Liu, Z. Y.; Ye, Y. F.; Sun, B. A.; Liu, C. T.

    2014-10-01

    One fundamental yet longstanding issue in materials science is how local inelasticity arises within an amorphous structure before yielding occurs. Although many possible scenarios were postulated or predicted by theories and simulations,however, direct experimental evidence has been lacking today due to the lack of a sensitive way to detect nano-scale inelasticity. Through the carefully designed microcompression method as coupled with the state-of-art nano-scale electric resistance measurement, we here unfold a stochastic inelastic deformation process in a Zr-based metallic glass, which takes place via the recurrence of two types of short-lived inelastic events causing structural damage and recovery, respectively, prior to yielding. Our current findings reveal that these stochastic events not only self-organize into sub-critical events due to elastic coupling, but also compete with each other in a way that enables the whole amorphous structure to self-heal as well as to sustain local damage.

  6. Processing used nuclear fuel with nanoscale control of uranium and ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Wylie, Ernest M.; Peruski, Kathryn M.; Prizio, Sarah E. [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556 (United States); Bridges, Andrea N.A.; Rudisill, Tracy S.; Hobbs, David T. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Phillip, William A. [Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 (United States); Burns, Peter C., E-mail: pburns@nd.edu [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2016-05-15

    Current separation and purification technologies utilized in the nuclear fuel cycle rely primarily on liquid–liquid extraction and ion-exchange processes. Here, we report a laboratory-scale aqueous process that demonstrates nanoscale control for the recovery of uranium from simulated used nuclear fuel (SIMFUEL). The selective, hydrogen peroxide induced oxidative dissolution of SIMFUEL material results in the rapid assembly of persistent uranyl peroxide nanocluster species that can be separated and recovered at moderate to high yield from other process-soluble constituents using sequestration-assisted ultrafiltration. Implementation of size-selective physical processes like filtration could results in an overall simplification of nuclear fuel cycle technology, improving the environmental consequences of nuclear energy and reducing costs of processing. - Highlights: • Nanoscale control in irradiated fuel reprocessing. • Ultrafiltration to recover uranyl cage clusters. • Alternative to solvent extraction for uranium purification.

  7. Ascertaining effects of nanoscale polymeric interfaces on competitive protein adsorption at the individual protein level

    Science.gov (United States)

    Song, Sheng; Xie, Tian; Ravensbergen, Kristina; Hahm, Jong-In

    2016-02-01

    With the recent development of biomaterials and biodevices with reduced dimensionality, it is critical to comprehend protein adhesion processes to nanoscale solid surfaces, especially those occurring in a competitive adsorption environment. Complex sequences of adhesion events in competitive adsorption involving multicomponent protein systems have been extensively investigated, but our understanding is still limited primarily to macroscopic adhesion onto chemically simple surfaces. We examine the competitive adsorption behavior from a binary protein mixture containing bovine serum albumin and fibrinogen at the single protein level. We subsequently evaluate a series of adsorption and displacement processes occurring on both the macroscopic homopolymer and nanoscopic diblock copolymer surfaces, while systematically varying the protein concentration and incubation time. We identify the similarities and dissimilarities in competitive protein adsorption behavior between the two polymeric surfaces, the former presenting chemical uniformity at macroscale versus the latter exhibiting periodic nanointerfaces of chemically alternating polymeric segments. We then present our novel experimental finding of a large increase in the nanointerface-engaged residence time of the initially bound proteins and further explain the origin of this phenomenon manifested on nanoscale diblock copolymer surfaces. The outcomes of this study may provide timely insight into nanoscale competitive protein adsorption that is much needed in designing bioimplant and tissue engineering materials. In addition, the fundamental understanding gained from this study can be beneficial for the development of highly miniaturized biodevices and biomaterials fabricated by using nanoscale polymeric materials and interfaces.With the recent development of biomaterials and biodevices with reduced dimensionality, it is critical to comprehend protein adhesion processes to nanoscale solid surfaces, especially those

  8. Integrated chemical and biological systems in nanowire structures towards nano-scale sensors

    Science.gov (United States)

    Hernandez, Rose M.

    Nanowires composed of metal and conducting polymers with integrated proteins and chemical systems have been investigated as building blocks for next-generation nano-scale sensors and assemblies. These nanowires were fabricated by combining chemical and electrochemical methods of synthesis of gold and conducting polymers in nanopores of anodized alumina membranes. Polymer nanowires were synthesized from buffer solutions as a mean to promote a biocompatible environment for the incorporation of proteins. A variety of proteins were incorporated into the polymer matrix by entrapment during polymerization that imparted the polymer material with biological functionality. Another class of composite nanowires containing electro-active conducting polymer junctions was developed for applications in chemical sensor arrays. The methodologies described in this thesis provide an inexpensive and straightforward approach to the synthesis of anisotropic nanoparticles incorporating a variety of biological and inorganic species that can be integrated to current microelectronic technologies for the development of nano-scale sensor arrays.

  9. Measuring broadband magnetic fields on the nanoscale using a hybrid quantum register

    Science.gov (United States)

    Jakobi, Ingmar; Neumann, Philipp; Wang, Ya; Dasari, Durga Bhaktavatsala Rao; El Hallak, Fadi; Bashir, Muhammad Asif; Markham, Matthew; Edmonds, Andrew; Twitchen, Daniel; Wrachtrup, Jörg

    2017-01-01

    The generation and control of fast switchable magnetic fields with large gradients on the nanoscale is of fundamental interest in material science and for a wide range of applications. However, it has not yet been possible to characterize those fields at high bandwidth with arbitrary orientations. Here, we measure the magnetic field generated by a hard-disk-drive write head with high spatial resolution and large bandwidth by coherent control of single electron and nuclear spins. We are able to derive field profiles from coherent spin Rabi oscillations close to the gigahertz range, measure magnetic field gradients on the order of 1 mT nm-1 and quantify axial and radial components of a static and dynamic magnetic field independent of its orientation. Our method paves the way for precision measurement of the magnetic fields of nanoscale write heads, which is important for future miniaturization of these devices.

  10. Nanoscale electromechanical and electronic properties of free-standing ZnO nano- and microstructured platelets

    Science.gov (United States)

    Faraji, N.; Adelung, R.; Mishra, Y. K.; Seidel, J.

    2017-10-01

    The piezoelectric response, conductivity and surface potential of individual grains and grain boundaries in free-standing polycrystalline ZnO nano- and microstructured platelets is studied using scanning probe based techniques on the nanoscale. We find that applied dc electric fields can alter the piezoresponse in individual grains, as well as the local nanoscale conductivity, and invert the relative surface potential at grain boundaries. This can be attributed to defect accumulation at the grain surfaces and at grain boundaries and the associated density of carriers. Together with recently observed below-bandgap photoconductivity at grain boundaries, the presented observation opens new venues for potential nanoelectronic applications that rely on grain and grain boundary engineering and functionality in a wide-bandgap transparent material.

  11. Nanoscale characterization of isolated individual type I collagen fibrils: polarization and piezoelectricity

    Energy Technology Data Exchange (ETDEWEB)

    Minary-Jolandan, Majid; Yu Minfeng [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)], E-mail: mfyu@uiuc.edu

    2009-02-25

    Piezoresponse force microscopy was applied to directly study individual type I collagen fibrils with diameters of {approx}100 nm isolated from bovine Achilles tendon. It was revealed that single collagen fibrils behave predominantly as shear piezoelectric materials with a piezoelectric coefficient on the order of 1 pm V{sup -1}, and have unipolar axial polarization throughout their entire length. It was estimated that, under reasonable shear load conditions, the fibrils were capable of generating an electric potential up to tens of millivolts. The result substantiates the nanoscale origin of piezoelectricity in bone and tendons, and implies also the potential importance of the shear load-transfer mechanism, which has been the principle basis of the nanoscale mechanics model of collagen, in mechanoelectric transduction in bone.

  12. The engagement of optical angular momentum in nanoscale chirality

    Science.gov (United States)

    Andrews, David L.

    2017-09-01

    Wide-ranging developments in optical angular momentum have recently led to refocused attention on issues of material chirality. The connection between optical spin and circular polarization, linking to well-known and utilized probes of chirality such as circular dichroism, has prompted studies aiming to achieve enhanced means of differentiating enantiomers - molecules or particles of opposite handedness. A number of newly devised schemes for physically separating mirror-image components by optical methods have also been gaining traction, together with a developing appreciation of how the scale of physical dimensions ultimately determines any capacity to differentially select for material chirality. The scope of such enquiries has substantially widened on recognition that suitably structured, topologically charged beams of light - often known as `twisted light' or `optical vortices' can additionally convey orbital angular momentum. A case can be made that understanding the full scope and constraints upon chiroptical interactions in the nanoscale regime involves the resolution of CPT symmetry conditions governing the fundamental interactions between matter and photons. The principles provide a sound theoretical test-bed for new methodologies.

  13. Review of soluble uranium removal by nanoscale zero valent iron.

    Science.gov (United States)

    Jing, C; Li, Y L; Landsberger, S

    2016-11-01

    Uranium (U) has been released to surface soil and groundwater through military and industrial activities. Soluble forms of U transferred to drinking water sources and food supplements can potentially threaten humans and the biosphere due to its chemical toxicity and radioactivity. The immobilization of aqueous U onto iron-based minerals is one of the most vital geochemical processes controlling the transport of U. As a consequence, much research has been focused on the use of iron-based materials for the treatment of U contaminated waters. One material currently being tested is nanoscale zero-valent iron (nZVI). However, understanding the removal mechanism of U onto nZVI is crucial to develop new technologies for contaminated water resources. This review article aims to provide information on the removal mechanism of U onto nZVI under different conditions (pH, U concentration, solution ion strength, humic acid, presence of O2 and CO2, microorganism effect) pertinent to environmental and engineered systems, and to provide risk or performance assessment results with the stability of nZVI products after removal of U in environmental restoration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. PHOTOELECTROCHEMISTRY AND PHOTOCATALYSIS IN NANOSCALE INORGANIC CHEMICAL SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Mallouk

    2007-05-27

    The goal of our DOE-supported research has been to explore the use of solid state materials as organizing media for, and as active components of, artificial photosynthetic systems. In this work we strive to understand how photoinduced electron and energy transfer reactions occur in the solid state, and to elucidate design principles for using nanoscale inorganic materials in photochemical energy conversion schemes. A unifying theme in this project has been to move beyond the study of simple transient charge separation to integrated chemical systems that can effect permanent charge separation in the form of energy-rich chemicals. This project explored the use of zeolites as organizing media for electron donor-acceptor systems and artificial photosynthetic assemblies. Layer-by-layer synthetic methods were developed using lamellar semiconductors, and multi-step, visible light driven energy/electron transfer cascades were studied by transient specroscopic techniques. By combining molecular photosensitizers with lamellar semiconductors and intercalated catalyst particles, the first non-sacrificial systems for visible light driven hydrogen evolution were developed and studied. Oxygen evolving catalyst particles and semiconductor nanowires were also studied with the goal of achieving photocatalytic water splitting using visible light.

  15. Optimization of nano-scale nickel/iron particles for the reduction of high concentration chlorinated aliphatic hydrocarbon solutions.

    Science.gov (United States)

    Barnes, Robert J; Riba, Olga; Gardner, Murray N; Scott, Thomas B; Jackman, Simon A; Thompson, Ian P

    2010-04-01

    The use of nano-scale particles as a means of environmental remediation still provides a comparatively novel approach for the treatment of contaminated waters. The current study compares the reactivity of micro-scale Fe, nano-scale Fe and nano-scale Ni/Fe (nickel/iron) particles specifically for dechlorination of solutions containing 350 mg L(-1) of TCE (concentration measured at a contaminated site in Derbyshire, UK). The results indicated that employing 1 g L(-1) of reactive material for dechlorination in the monometallic form (both micro- and nano-scale) exhibited very little reduction capability compared with the bimetallic Ni/Fe nano-scale particles, containing 28.9% Ni (in molar), which achieved complete dechlorination of the TCE in solution within 576 h. Experiments were also performed to determine the optimum bimetallic composition of the Ni/Fe particles for TCE reduction. This revealed that 3.2% Ni was the optimum Ni/Fe molar ratio for both maximum dehalogenation performance and minimum release of Ni into solution. Using particles of the most effective bimetallic composition, experiments were carried out to determine the concentration required for optimal TCE reduction. Over the range of nano-scale particle concentrations tested (0.1-9 g L(-1)), reduction rates of TCE increased with greater TCE:nano-scale particle ratios. However, a concentration range of 1-3 g L(-1) was selected as the most appropriate for site remediation, since more concentrated solutions demonstrated only small increases in rates of reaction. Finally, in order to test the long term performance and reactivity of the 3.2% Ni/Fe bimetallic nano-scale particles, weekly spikes of 350 mg L(-1) TCE were injected into a 3 g L(-1) nano-scale particle batch reactor. Results showed that the bimetallic nano-scale particles had the ability to reduce 1750 mg L(-1) TCE and remained active for at least 13 weeks. (c) 2010 Elsevier Ltd. All rights reserved.

  16. Nano-scale polar-nonpolar oxide heterostructures for photocatalysis

    Science.gov (United States)

    Guo, Hongli; Saidi, Wissam A.; Yang, Jinlong; Zhao, Jin

    2016-03-01

    We proposed based on first principles density functional theory calculations that a nano-scale thin film based on a polar-nonpolar transition-metal oxide heterostructure can be used as a highly-efficient photocatalyst. This is demonstrated using a SrTiO3/LaAlO3/SrTiO3 sandwich-like heterostructure with photocatalytic activity in the near-infrared region. The effect of the polar nature of LaAlO3 is two-fold. First, the induced electrostatic field accelerates the photo-generated electrons and holes into opposite directions and minimizes their recombination rates. Hence, the reduction and oxidation reactions can be instigated at the SrTiO3 surfaces located on the opposite sides of the heterostructure. Second, the electric field reduces the band gap of the system making it photoactive in the infrared region. We also show that charge separation can be enhanced by using compressive strain engineering that creates ferroelectric instability in STO. The proposed setup is ideal for tandem oxide photocatalysts especially when combined with photoactive polar materials.We proposed based on first principles density functional theory calculations that a nano-scale thin film based on a polar-nonpolar transition-metal oxide heterostructure can be used as a highly-efficient photocatalyst. This is demonstrated using a SrTiO3/LaAlO3/SrTiO3 sandwich-like heterostructure with photocatalytic activity in the near-infrared region. The effect of the polar nature of LaAlO3 is two-fold. First, the induced electrostatic field accelerates the photo-generated electrons and holes into opposite directions and minimizes their recombination rates. Hence, the reduction and oxidation reactions can be instigated at the SrTiO3 surfaces located on the opposite sides of the heterostructure. Second, the electric field reduces the band gap of the system making it photoactive in the infrared region. We also show that charge separation can be enhanced by using compressive strain engineering that creates

  17. Coal surface control for advanced fine coal flotation. Final report, October 1, 1988--March 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Fuerstenau, D.W.; Hanson, J.S.; Diao, J.; Harris, G.H.; De, A.; Sotillo, F. [California Univ., Berkeley, CA (United States); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. [Columbia Univ., New York, NY (United States); Hu, W.; Zou, Y.; Chen, W. [Utah Univ., Salt Lake City, UT (United States); Choudhry, V.; Shea, S.; Ghosh, A.; Sehgal, R. [Praxis Engineers, Inc., Milpitas, CA (United States)

    1992-03-01

    The initial goal of the research project was to develop methods of coal surface control in advanced froth flotation to achieve 90% pyritic sulfur rejection, while operating at Btu recoveries above 90% based on run-of-mine quality coal. Moreover, the technology is to concomitantly reduce the ash content significantly (to six percent or less) to provide a high-quality fuel to the boiler (ash removal also increases Btu content, which in turn decreases a coal`s emission potential in terms of lbs SO{sub 2}/million Btu). (VC)

  18. Nanoscale device physics science and engineering fundamentals

    CERN Document Server

    Tiwari, Sandip

    2017-01-01

    Nanoscale devices are distinguishable from the larger microscale devices in their specific dependence on physical phenomena and effects that are central to their operation. The size change manifests itself through changes in importance of the phenomena and effects that become dominant and the changes in scale of underlying energetics and response. Examples of these include classical effects such as single electron effects, quantum effects such as the states accessible as well as their properties; ensemble effects ranging from consequences of the laws of numbers to changes in properties arising from different magnitudes of the inter-actions, and others. These interactions, with the limits placed on size, make not just electronic, but also magnetic, optical and mechanical behavior interesting, important and useful. Connecting these properties to the behavior of devices is the focus of this textbook. Description of the book series: This collection of four textbooks in the Electroscience series span the undergrad...

  19. 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.

  20. Nanoscale control of phonon excitations in graphene

    Science.gov (United States)

    Kim, Hyo Won; Ko, Wonhee; Ku, Jiyeon; Ryu, Seunghwa; Hwang, Sung Woo

    Phonons, which are collective excitations in a lattice of atoms or molecules, play a major role in determining various physical properties of condensed matter, such as thermal and electrical conductivities. In particular, phonons in graphene interact strongly with electrons; however, unlike in usual metals, these interactions between phonons and massless Dirac fermions appear to mirror the rather complicated physics of those between light and relativistic electrons. Therefore, a fundamental understanding of the underlying physics through systematic studies of phonon interactions and excitations in graphene is crucial for realizing graphene-based devices. In this study, we demonstrate that the local phonon properties of graphene can be controlled at the nanoscale by tuning the interaction strength between graphene and an underlying Pt substrate. Using scanning probe methods, we determine that the reduced interaction due to embedded Ar atoms facilitates electron-phonon excitations, further influencing phonon-assisted inelastic electron tunneling.

  1. Managing Temperature Effects in Nanoscale Adaptive Systems

    CERN Document Server

    Wolpert, David

    2012-01-01

    This book discusses new techniques for detecting, controlling, and exploiting the impacts of temperature variations on nanoscale circuits and systems.  It provides a holistic discussion of temperature management, including physical phenomena (reversal of the MOSFET temperature dependence) that have recently become problematic, along with circuit techniques for detecting, controlling, and adapting to these phenomena. A detailed discussion is also included of the general aspects of thermal-aware system design and management of temperature-induced faults. A new sensor system is described that can determine the temperature dependence as well as the operating temperature to improve system reliability.  A new method is presented to control a circuit’s temperature dependence by individually tuning pull-up and pull-down networks to their temperature-insensitive operating points. This method extends the range of supply voltages that can be made temperature-insensitive, achieving insensitivity at nominal voltage fo...

  2. Nanoscale Particle Motion in Attractive Polymer Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Senses, Erkan; Narayanan, Suresh; Mao, Yimin; Faraone, Antonio

    2017-12-06

    Using x-ray photon correlation spectroscopy, we examined slow nanoscale motion of silica nanoparticles individually dispersed in entangled poly (ethylene oxide) melt at particle volume fractions up to 42 %. The nanoparticles, therefore, serve as both fillers for the resulting attractive polymer nanocomposites and probes for the network dynamics therein. The results show that the particle relaxation closely follows the mechanical reinforcement in the nanocomposites only at the intermediate concentrations below the critical value for the chain confinement. Quite unexpectedly, the relaxation time of the particles does not further slowdown at higher volume fractions- when all chains are practically on the nanoparticle interface- and decouples from the elastic modulus of the nanocomposites that further increases orders of magnitude.

  3. 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.

  4. Nanoscale magnetic heat pumps and engines

    Science.gov (United States)

    Bauer, Gerrit E. W.; Bretzel, Stefan; Brataas, Arne; Tserkovnyak, Yaroslav

    2010-01-01

    We present the linear-response matrix for a sliding domain wall in a rotatable magnetic nanowire, which is driven out of equilibrium by temperature and voltage bias, mechanical torque, and magnetic field. An expression for heat-current-induced domain-wall motion is derived. Application of Onsager’s reciprocity relation leads to a unified description of the Barnett and Einstein-de Haas effects as well as spin-dependent thermoelectric properties. We envisage various heat pumps and engines, such as coolers driven by magnetic fields or mechanical rotation as well as nanoscale motors that convert temperature gradients into useful work. All parameters (with the exception of mechanical friction) can be computed microscopically by the scattering theory of transport.

  5. Control of friction at the nanoscale

    Science.gov (United States)

    Barhen, Jacob; Braiman, Yehuda Y.; Protopopescu, Vladimir

    2010-04-06

    Methods and apparatus are described for control of friction at the nanoscale. A method of controlling frictional dynamics of a plurality of particles using non-Lipschitzian control includes determining an attribute of the plurality of particles; calculating an attribute deviation by subtracting the attribute of the plurality of particles from a target attribute; calculating a non-Lipschitzian feedback control term by raising the attribute deviation to a fractionary power .xi.=(2m+1)/(2n+1) where n=1, 2, 3 . . . and m=0, 1, 2, 3 . . . , with m strictly less than n and then multiplying by a control amplitude; and imposing the non-Lipschitzian feedback control term globally on each of the plurality of particles; imposing causes a subsequent magnitude of the attribute deviation to be reduced.

  6. Towards Nanoscale Biomedical Devices in Medicine

    DEFF Research Database (Denmark)

    Parracino, A.; Gajula, G.P.; di Gennaro, A.K.

    2011-01-01

    Medical interest in nanotechnology originates from a belief that nanoscale therapeutic devices can be constructed and directed towards its target inside the human body. Such nanodevices can be engineered by coupling superparamagnetic nanoparticle to biomedically active proteins. We hereby report...... the immobilization of a PhEst, a S-formylglutathione hydrolase from the psychrophilic P. haloplanktis TAC125 onto the gold coated surface of modified superparamagnetic core-shell nanoparticles (FeO@Au). The synthesis of the nanoparticles is also reported. S-formylglutathione hydrolases constitute a family...... nanoparticles, the binding and activity of the enzyme onto the nanoparticles. Activity data in U/ml confirmed that the immobilized enzyme is approximately 2 times more active than the free enzyme in solution. Such particles can be directed with external magnetic fields for bio-separation and focused towards...

  7. Wireless communication system via nanoscale plasmonic antennas.

    Science.gov (United States)

    Merlo, Juan M; Nesbitt, Nathan T; Calm, Yitzi M; Rose, Aaron H; D'Imperio, Luke; Yang, Chaobin; Naughton, Jeffrey R; Burns, Michael J; Kempa, Krzysztof; Naughton, Michael J

    2016-08-24

    Present on-chip optical communication technology uses near-infrared light, but visible wavelengths would allow system miniaturization and higher energy confinement. Towards this end, we report a nanoscale wireless communication system that operates at visible wavelengths via in-plane information transmission. Here, plasmonic antenna radiation mediates a three-step conversion process (surface plasmon → photon → surface plasmon) with in-plane efficiency (plasmon → plasmon) of 38% for antenna separation 4λ0 (with λ0 the free-space excitation wavelength). Information transmission is demonstrated at bandwidths in the Hz and MHz ranges. This work opens the possibility of optical conveyance of information using plasmonic antennas for on-chip communication technology.

  8. PREFACE: Selected papers from the Fourth Topical Conference on Nanoscale Science and Engineering of the American Institute of Chemical Engineers

    Science.gov (United States)

    Wong, Michael S.; Lee, Gil U.

    2005-07-01

    This special issue of Nanotechnology contains research papers contributed by the participants of the Fourth Topical Conference on Nanoscale Science and Engineering at the Annual Meeting of the American Institute of Chemical Engineers (AIChE), which was held in Austin, Texas, USA, 7-12 November, 2004. This conference saw 284 oral presentations from institutions around the world, which is the highest number for this topical conference series to date. These presentations were organized into 64 sessions, covering the range of nanotechnology subject areas in which chemical engineers are currently engaged. These sessions included the following areas. • Fundamentals: thermodynamics at the nanoscale; applications of nanostructured fluids; transport properties in nanophase and nanoscale systems; molecular modelling methods; self and directed assembly at the nanoscale; nanofabrication and nanoscale processing; manipulation of nanophases by external fields; nanoscale systems; adsorption and transport in carbon nanotubes; nanotribology; making the transition from materials and phenomena to new technologies; operation of micro-and nano-systems. • Materials: nanoparticle synthesis and stabilization; nanoscale structure in polymers; nanotemplating of polymers; synthesis of carbon nanotubes and nanotube-based materials; nanowires; nanoparticle assemblies and superlattices; nanoelectronic materials; self-assembly of templated inorganic materials; nanostructured hybrid organic/inorganic materials; gas phase synthesis of nanoparticles; multicomponent structured particles; nano energetic materials; liquid-phase synthesis of nanoparticles. • Energy: synthesis and characterization of nanostructured catalytic materials; nanomaterials and devices for energy applications. • Biotechnology: nanobiotechnology; nanotechnology for the biotechnology and pharmaceuticals industries; nanotechnology and nanobiotechnology for sensors; advances in biomaterials, bionanotechnology, biomimetic

  9. A highly tunable silicone-based magnetic elastomer with nanoscale homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Benjamin A., E-mail: ben.evans@elon.edu [Department of Physics, Elon University, CB 2625, Elon, NC 27244 (United States); Fiser, Briana L. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Prins, Willem J.; Rapp, Daniel J. [Department of Physics, Elon University, CB 2625, Elon, NC 27244 (United States); Shields, Adam R. [Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, SW Washington, DC 20375 (United States); Glass, Daniel R. [Department of Physics, Elon University, CB 2625, Elon, NC 27244 (United States); Superfine, R. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States)

    2012-02-15

    Magnetic elastomers have been widely pursued for sensing and actuation applications. Silicone-based magnetic elastomers have a number of advantages over other materials such as hydrogels, but aggregation of magnetic nanoparticles within silicones is difficult to prevent. Aggregation inherently limits the minimum size of fabricated structures and leads to non-uniform response from structure to structure. We have developed a novel material that is a complex of a silicone polymer (polydimethylsiloxane-co-aminopropylmethylsiloxane) adsorbed onto the surface of magnetite ({gamma}-Fe{sub 2}O{sub 3}) nanoparticles 7-10 nm in diameter. The material is homogenous at very small length scales (<100 nm) and can be crosslinked to form a flexible magnetic material, which is ideally suited for the fabrication of micro- to nanoscale magnetic actuators. The loading fraction of magnetic nanoparticles in the composite can be varied smoothly from 0 to 50 wt% without loss of homogeneity, providing a simple mechanism for tuning actuator response. We evaluate the material properties of the composite across a range of nanoparticle loading, and demonstrate a magnetic-field-induced increase in compressive modulus as high as 300%. Furthermore, we implement a strategy for predicting the optimal nanoparticle loading for magnetic actuation applications, and show that our predictions correlate well with experimental findings. - Highlights: > Silicone-magnetite elastomer with nanoscale homogeneity. > Iron content tunable from 0 to 50 wt% without aggregation. > Elastic modulus increases in magnetic field. > Model and experiment show maximal actuation for microstructures near 40 wt% iron.

  10. Using mathematical models to understand the effect of nanoscale roughness on protein adsorption for improving medical devices.

    Science.gov (United States)

    Ercan, Batur; Khang, Dongwoo; Carpenter, Joseph; Webster, Thomas J

    2013-01-01

    Surface roughness and energy significantly influence protein adsorption on to biomaterials, which, in turn, controls select cellular adhesion to determine the success and longevity of an implant. To understand these relationships at a fundamental level, a model was originally proposed by Khang et al to correlate nanoscale surface properties (specifically, nanoscale roughness and energy) to protein adsorption, which explained the greater cellular responses on nanostructured surfaces commonly reported in the literature today. To test this model for different surfaces from what was previously used to develop that model, in this study we synthesized highly ordered poly(lactic-co-glycolic acid) surfaces of identical chemistry but altered nanoscale surface roughness and energy using poly(dimethylsiloxane) molds of polystyrene beads. Fibronectin and collagen type IV adsorption studies showed a linear adsorption behavior as the surface nanoroughness increased. This supported the general trends observed by Khang et al. However, when fitting such data to the mathematical model established by Khang et al, a strong correlation did not result. Thus, this study demonstrated that the equation proposed by Khang et al to predict protein adsorption should be modified to accommodate for additional nanoscale surface property contributions (ie, surface charge) to make the model more accurate. In summary, results from this study provided an important step in developing future mathematical models that can correlate surface properties (such as nanoscale roughness and surface energy) to initial protein adsorption events important to promote select cellular adhesion. These criteria are critical for the fundamental understanding of the now well-documented increased tissue growth on nanoscale materials.

  11. Nanoscale Mechanical Stimulation of Human Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    H Nikukar

    2014-05-01

    We observed significant responses after 1 and 2-week stimulations in cell number, cell shapes and phenotypical markers. Microarray was performed for all groups. Cell count showed normal cell growth with stimulation. However, cell surface area, cell perimeter, and arboration after 1-week stimulation showed significant increases. Immunofluorescent studies have showed significant increase in osteocalcin production after stimulation. Conclusions: Nanoscale mechanical vibration showed significant changes in human mesenchymal stem cell behaviours. Cell morphology changed to become more polygonal and increased expression of the osteoblast markers were noted. These findings with gene regulation changes suggesting nanoscale mechanostimulation has stimulated osteoblastogenesis.  Keywords:  Mesenchymal, Nanoscale, Stem Cells.

  12. The Architectural Designs of a Nanoscale Computing Model

    Directory of Open Access Journals (Sweden)

    Mary M. Eshaghian-Wilner

    2004-08-01

    Full Text Available A generic nanoscale computing model is presented in this paper. The model consists of a collection of fully interconnected nanoscale computing modules, where each module is a cube of cells made out of quantum dots, spins, or molecules. The cells dynamically switch between two states by quantum interactions among their neighbors in all three dimensions. This paper includes a brief introduction to the field of nanotechnology from a computing point of view and presents a set of preliminary architectural designs for fabricating the nanoscale model studied.

  13. A nanoscale perspective on the effects of transverse microprestress on drying creep of nanoporous solids

    Science.gov (United States)

    Sinko, Robert; Bažant, Zdeněk P.; Keten, Sinan

    2018-01-01

    The Pickett effect describes the excess non-additive strain developed during drying of a nanoporous solid material under creep. One explanation for its origins, developed using micromechanical models, is the progressive relaxation of internally developed microprestress. However, these models have not explicitly considered the effects of this microprestress on nanoscale energy barriers that govern the relative motion and displacement between nanopore walls during deformation. Here, we evaluate the nanoscale effects of transverse microprestresses on the drying creep behaviour of a nanoscale slit pore using coarse-grained molecular dynamics. We find that the underlying energy barrier depends exponentially on the transverse microprestress, which is attributed to changes in the effective viscosity and degree of nanoconfinement of molecules in the water interlayer. Specifically, as the transverse microprestress is relaxed (i.e. its magnitude decreases), the activation energy barrier is reduced, thereby leading to an acceleration of the creep behaviour and a stronger Pickett effect. Based on our simulation results, we introduce a new microprestress-dependent energy term into our existing Arrhenius model, which describes the relative displacement of pore walls as a function of the underlying activation energy barriers. Our findings further verify the existing micromechanical theories for the origin of the Pickett effect and establish a quantitative relationship between the transverse microprestress and the intensity of the Pickett effect.

  14. Nanoscale tipped microwire arrays enhance electrical trap and depth injection of nanoparticles.

    Science.gov (United States)

    Goryu, Akihiro; Numano, Rika; Ikedo, Akihito; Ishida, Makoto; Kawano, Takeshi

    2012-10-19

    Nanoscale devices have the potential to measure biological tissues as well as individual cells/neurons. However, three-dimensional (3D) multi-site probing remains problematic because only planar-type device designs are applicable to sample surfaces. Herein we report 3D nanoscale electrode tipped microwire arrays with high aspect ratios. A nanoscale tipped wire is formed by isotropic silicon etching to the tip of a vapor-liquid-solid grown silicon microwire. After coating the wire with a metal (e.g., Pt and Au), only the nanotip section can be exposed from the surrounding outer shell (e.g., SiO(2) and parylene) by photoresist spray coating and subsequent cycled photoresist etchings. As a promising device application, we demonstrate the trapping of polystyrene nanoparticles in a solution using a fabricated Au-nanotip wire array. The sharpened nanotip has a 150 nm curvature radius and a 4.2 μm(2) electrode area. The nanotip wires exhibit a locally enhanced trapping performance with a low trapping voltage of 20 mV. Moreover, these trapped nanoparticles can be injected into a soft material (gelatin), demonstrating a multi-site wide-area batch depth injection and an assembly of nanoparticles. Such nanotip wire arrays should be applicable to trap numerous particles, including DNA/molecules attached to Au particles, and may realize injection into biological tissues and individual cells/neurons.

  15. 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.

  16. Nanoscale Drug Delivery Systems for Enhanced Drug Penetration into Solid Tumors: Current Progress and Opportunities

    Science.gov (United States)

    Waite, Carolyn L.; Roth, Charles M.

    2013-01-01

    Poor penetration of anticancer drugs into solid tumors significantly limits their efficacy. This phenomenon has long been observed for small-molecule chemotherapeutics, and it can be even more pronounced for nanoscale therapies. Nanoparticles have enormous potential for the treatment of cancer due to their wide applicability as drug delivery and imaging vehicles and their size-dependent accumulation into solid tumors by the enhanced permeability and retention (EPR) effect. Further, synthetic nanoparticles can be engineered to overcome barriers to drug delivery. Despite their promise for the treatment of cancer, relatively little work has been done to study and improve their ability to diffuse into solid tumors following passive accumulation in the tumor vasculature. In this review, we present the complex issues governing efficient penetration of nanoscale therapies into solid tumors. The current methods available to researchers to study nanoparticle penetration into malignant tumors are described, and the most recent works studying the penetration of nanoscale materials into solid tumors are summarized. We conclude with an overview of the important nanoparticle design parameters governing their tumor penetration, as well as by highlighting critical directions in this field. PMID:22428797

  17. Stick-Slip Instabilities for Interfacial Chemical Bond-Induced Friction at the Nanoscale.

    Science.gov (United States)

    Tian, Kaiwen; Gosvami, Nitya N; Goldsby, David L; Carpick, Robert W

    2017-12-08

    Earthquakes are generally caused by unstable stick-slip motion of faults. This stick-slip phenomenon, along with other frictional properties of materials at the macroscale, is well-described by empirical rate and state friction (RSF) laws. Here we study stick-slip behavior for nanoscale single-asperity silica-silica contacts in atomic force microscopy experiments. The stick-slip is quasiperiodic, and both the amplitude and spatial period of stick-slip increase with normal load and decrease with the loading point (i.e., scanning) velocity. The peak force prior to each slip increases with the temporal period logarithmically, and decreases with velocity logarithmically, consistent with stick-slip behavior at the macroscale. However, unlike macroscale behavior, the minimum force after each slip is independent of velocity. The temporal period scales with velocity in a nearly power law fashion with an exponent between -1 and -2, similar to macroscale behavior. With increasing velocity, stick-slip behavior transitions into steady sliding. In the transition regime between stick-slip and smooth sliding, some slip events exhibit only partial force drops. The results are interpreted in the context of interfacial chemical bond formation and rate effects previously identified for nanoscale contacts. These results contribute to a physical picture of interfacial chemical bond-induced stick-slip, and further establish RSF laws at the nanoscale.

  18. Strain engineering on silicon/germanium nanoscale heterostructures using molecular dynamics

    Science.gov (United States)

    Park, Yumi

    Nanoscale architectures provide additional variables to engineer electronic/mechanical properties of material systems due to their high surface volume ratio and physics that arise from their extremely small size. To date, the device performance of microelectronics has been improved largely by miniaturization. However, with feature sizes below 100 nm, the fundamental challenges demand development of new architectures, new materials, and strain engineering. Strain engineering has been one of the most widely used techniques to achieve desired electronic properties of materials. For example, uniaxial compression and tension are desirable for high speed p-and n-MOSFET, respectively. However, accurate experimental characterization of strain in nanomaterials remains challenges such as resolving strain components and quantifying strain gradient which can affect electronic properties. Molecular dynamics (MD) describe materials with atomic resolution and it can provide invaluable information and insight into nanoscale strain engineering. MD simulations are used to study strain relaxation in Si/Ge heteroepitaxial structures of interest to nanoelectonic applications. Nanopatterning is considered as an avenue for strain engineering to achieve uniaxial strain state from epitaxially integrated Si/Ge heterostructures. Using MD, it is studied how size affect strain relaxation on strained Si/Ge/Si nanobars representing the structures obtained by patterning the films in nanoscale. The MD results demonstrate that Ge with a roughly square cross section has a uniaxial strain state desirable for hole mobility enhancement. Also, process-induced strain relaxation on Si/Ge heterostructures is discussed. The simulations suggest that, by engineering the aspect ratio of Si/Ge nanolaminates, local amorphization followed by recrystallization can be used for either preserving the engineered strain or achieving the desired strain state in crystalline region, showing a possibility as a new avenue

  19. Sculpturing the electron wave function using nanoscale phase masks

    Energy Technology Data Exchange (ETDEWEB)

    Shiloh, Roy, E-mail: royshilo@post.tau.ac.il; Lereah, Yossi; Lilach, Yigal; Arie, Ady

    2014-09-15

    Electron beams are extensively used in lithography, microscopy, material studies and electronic chip inspection. Today, beams are mainly shaped using magnetic or electric forces, enabling only simple shaping tasks such as focusing or scanning. Recently, binary amplitude gratings achieved complex shapes. These, however, generate multiple diffraction orders, hence the desired shape, appearing only in one order, retains little of the beam energy. Here we demonstrate a method in electron-optics for arbitrarily shaping electron beams into a single desired shape, by precise patterning of a thin-membrane. It is conceptually similar to shaping light beams using refractive or diffractive glass elements such as lenses or holograms – rather than applying electromagnetic forces, the beam is controlled by spatially modulating its wavefront. Our method allows for nearly-maximal energy transference to the designed shape, and may avoid physical damage and charging effects that are the scorn of commonly-used (e.g. Zernike and Hilbert) phase-plates. The experimental demonstrations presented here – on-axis Hermite–Gauss and Laguerre–Gauss (vortex) beams, and computer-generated holograms – are a first example of nearly-arbitrary manipulation of electron beams. Our results herald exciting prospects for microscopic material studies, enables electron lithography with fixed sample and beam and high resolution electronic chip inspection by structured electron illumination. - Highlights: • Nanoscale-patterned membranes are used to shape electron beams. • Designing on-axis phase plates outside the back focal plane is possible. • Computer-generated holograms enable nearly-arbitrary beam shaping. • Applications in microscopy, lithography, chip inspection and material sciences.

  20. Picasso at the Nanoscale: The Art of Using Cutting-Edge Science to Understand Cultural Heritage

    Science.gov (United States)

    Rose, Volker

    2015-03-01

    Scientists are using high-energy X-ray instruments to solve mysteries behind art masterpieces, including artwork by Picasso. Learn how Argonne National Laboratory is working with major art institutions, such as The Art Institute of Chicago and Smithsonian Institute, to unlock groundbreaking information about art, the artist, and our cultural heritage. A deep connection to our past and shared cultural heritage must be preserved to foster a balanced society where all humanity can thrive. This talk will describe analysis of paint materials used by Pablo Picasso at the nanoscale, as only possible at the brightest synchrotron sources. It will highlight how new imaging techniques can reveal the invisible, bringing to light underlying compositions of old masters' paintings. This in turn enables the writing of new art history and provides important material clues that can assist with attribution and authentication. We will explain how the use of new technology can lead to new discoveries, which, in turn, can change the public's and the specialists' perception of great works of art. In collaboration with scientists from The Art Institute of Chicago we have teamed up to study the chemical make up of zinc oxide pigments used in artworks by Pablo Picasso. We will show how highly focused X-ray beams with nanoscale spatial resolution and trace element sensitivity have helped to determine that Picasso has used conventional house paint in some of his paintings. Surprisingly, the study gives also new insights into the pigment material zinc oxide, which has also great potential in a variety of applications such as in spintronics or as transparent electrodes in solar panels. Work at the Advanced Photon Source and the Center for Nanoscale Materials was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DEAC02-06CH11357.

  1. Load and Time Dependence of Interfacial Chemical Bond-Induced Friction at the Nanoscale

    Science.gov (United States)

    Tian, Kaiwen; Gosvami, Nitya N.; Goldsby, David L.; Liu, Yun; Szlufarska, Izabela; Carpick, Robert W.

    2017-02-01

    Rate and state friction (RSF) laws are widely used empirical relationships that describe the macroscale frictional behavior of a broad range of materials, including rocks found in the seismogenic zone of Earth's crust. A fundamental aspect of the RSF laws is frictional "aging," where friction increases with the time of stationary contact due to asperity creep and/or interfacial strengthening. Recent atomic force microscope (AFM) experiments and simulations found that nanoscale silica contacts exhibit aging due to the progressive formation of interfacial chemical bonds. The role of normal load (and, thus, normal stress) on this interfacial chemical bond-induced (ICBI) friction is predicted to be significant but has not been examined experimentally. Here, we show using AFM that, for nanoscale ICBI friction of silica-silica interfaces, aging (the difference between the maximum static friction and the kinetic friction) increases approximately linearly with the product of the normal load and the log of the hold time. This behavior is attributed to the approximately linear dependence of the contact area on the load in the positive load regime before significant wear occurs, as inferred from sliding friction measurements. This implies that the average pressure, and thus the average bond formation rate, is load independent within the accessible load range. We also consider a more accurate nonlinear model for the contact area, from which we extract the activation volume and the average stress-free energy barrier to the aging process. Our work provides an approach for studying the load and time dependence of contact aging at the nanoscale and further establishes RSF laws for nanoscale asperity contacts.

  2. Single molecule-level study of donor-acceptor interactions and nanoscale environment in blends

    Science.gov (United States)

    Quist, Nicole; Grollman, Rebecca; Rath, Jeremy; Robertson, Alex; Haley, Michael; Anthony, John; Ostroverkhova, Oksana

    2017-02-01

    Organic semiconductors have attracted considerable attention due to their applications in low-cost (opto)electronic devices. The most successful organic materials for applications that rely on charge carrier generation, such as solar cells, utilize blends of several types of molecules. In blends, the local environment strongly influences exciton and charge carrier dynamics. However, relationship between nanoscale features and photophysics is difficult to establish due to the lack of necessary spatial resolution. We use functionalized fluorinated pentacene (Pn) molecule as single molecule probes of intermolecular interactions and of the nanoscale environment in blends containing donor and acceptor molecules. Single Pn donor (D) molecules were imaged in PMMA in the presence of acceptor (A) molecules using wide-field fluorescence microscopy. Two sample configurations were realized: (i) a fixed concentration of Pn donor molecules, with increasing concentration of acceptor molecules (functionalized indenflouorene or PCBM) and (ii) a fixed concentration of acceptor molecules with an increased concentration of the Pn donor. The D-A energy transfer and changes in the donor emission due to those in the acceptor- modified polymer morphology were quantified. The increase in the acceptor concentration was accompanied by enhanced photobleaching and blinking of the Pn donor molecules. To better understand the underlying physics of these processes, we modeled photoexcited electron dynamics using Monte Carlo simulations. The simulated blinking dynamics were then compared to our experimental data, and the changes in the transition rates were related to the changes in the nanoscale environment. Our study provides insight into evolution of nanoscale environment during the formation of bulk heterojunctions.

  3. Load and Time Dependence of Interfacial Chemical Bond-Induced Friction at the Nanoscale.

    Science.gov (United States)

    Tian, Kaiwen; Gosvami, Nitya N; Goldsby, David L; Liu, Yun; Szlufarska, Izabela; Carpick, Robert W

    2017-02-17

    Rate and state friction (RSF) laws are widely used empirical relationships that describe the macroscale frictional behavior of a broad range of materials, including rocks found in the seismogenic zone of Earth's crust. A fundamental aspect of the RSF laws is frictional "aging," where friction increases with the time of stationary contact due to asperity creep and/or interfacial strengthening. Recent atomic force microscope (AFM) experiments and simulations found that nanoscale silica contacts exhibit aging due to the progressive formation of interfacial chemical bonds. The role of normal load (and, thus, normal stress) on this interfacial chemical bond-induced (ICBI) friction is predicted to be significant but has not been examined experimentally. Here, we show using AFM that, for nanoscale ICBI friction of silica-silica interfaces, aging (the difference between the maximum static friction and the kinetic friction) increases approximately linearly with the product of the normal load and the log of the hold time. This behavior is attributed to the approximately linear dependence of the contact area on the load in the positive load regime before significant wear occurs, as inferred from sliding friction measurements. This implies that the average pressure, and thus the average bond formation rate, is load independent within the accessible load range. We also consider a more accurate nonlinear model for the contact area, from which we extract the activation volume and the average stress-free energy barrier to the aging process. Our work provides an approach for studying the load and time dependence of contact aging at the nanoscale and further establishes RSF laws for nanoscale asperity contacts.

  4. Dispersions of Aramid Nanofibers: A New Nanoscale Building Block

    Science.gov (United States)

    Yang, Ming; Cao, Keqin; Sui, Lang; Qi, Ying; Zhu, Jian; Waas, Anthony; Arruda, Ellen M.; Kieffer, John; Thouless, M. D.; Kotov, Nicholas A.

    2011-01-01

    Stable dispersions of nanofibers are virtually unknown for synthetic polymers. They can complement analogous dispersions of inorganic components, such as nanoparticles, nanowires, nanosheets, etc as a fundamental component of a toolset for design of nanostructures and metamaterials via numerous solvent-based processing methods. As such, strong flexible polymeric nanofibers are very desirable for the effective utilization within composites of nanoscale inorganic components such as nanowires, carbon nanotubes, graphene, and others. Here stable dispersions of uniform high-aspect-ratio aramid nanofibers (ANFs) with diameters between 3 and 30 nm and up to 10 μm in length were successfully obtained. Unlike the traditional approaches based on polymerization of monomers, they are made by controlled dissolution of standard macroscale form of the aramid polymer, i.e. well known Kevlar threads, and revealed distinct morphological features similar to carbon nanotubes. ANFs are successfully processed into films using layer-by-layer (LBL) assembly as one of the potential methods of preparation of composites from ANFs. The resultant films are transparent and highly temperature resilient. They also display enhanced mechanical characteristics making ANF films highly desirable as protective coatings, ultrastrong membranes, as well as building blocks of other high performance materials in place of or in combination with carbon nanotubes. PMID:21800822

  5. Resolving ultrafast exciton migration in organic solids at the nanoscale

    Science.gov (United States)

    Penwell, Samuel B.; Ginsberg, Lucas D. S.; Noriega, Rodrigo; Ginsberg, Naomi S.

    2017-11-01

    Effectiveness of molecular-based light harvesting relies on transport of excitons to charge-transfer sites. Measuring exciton migration, however, has been challenging because of the mismatch between nanoscale migration lengths and the diffraction limit. Instead of using bulk substrate quenching methods, here we define quenching boundaries all-optically with sub-diffraction resolution, thus characterizing spatiotemporal exciton migration on its native nanometre and picosecond scales. By transforming stimulated emission depletion microscopy into a time-resolved ultrafast approach, we measure a 16-nm migration length in poly(2,5-di(hexyloxy)cyanoterephthalylidene) conjugated polymer films. Combined with Monte Carlo exciton hopping simulations, we show that migration in these films is essentially diffusive because intrinsic chromophore energetic disorder is comparable to chromophore inhomogeneous broadening. Our approach will enable previously unattainable correlation of local material structure to exciton migration character, applicable not only to photovoltaic or display-destined organic semiconductors but also to explaining the quintessential exciton migration exhibited in photosynthesis.

  6. 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.

  7. Carbon nanotube Y-junctions for Nanoscale Electronics

    Science.gov (United States)

    Bandaru, Prabhakar; Daraio, Chiara; Jin, Sungho; Rao, Apparao

    2006-03-01

    Carbon Nanotube (CNT) based electronics offer significant potential, as a nanoscale alternative to silicon based devices, for novel molecular electronics technologies. To realize truly nanoelectronic architecture, it is desirable to have a fully integrated nanotube based technology, where both devices and interconnects are based on CNTs. With this aim in mind, we report on the electrical properties of CNT based Y-junctions. The carrier delocalization and the inevitable presence of catalyst particles, introduced during growth, at the junction region induce a net charge and scattering which can be exploited in constructing electronic devices. We have assembled and electrically characterized the DC resistance and the AC impedance of several Y-junction devices^2 with possibilities for switching and transistor related applications. These experiments alert us to the vast potentialities of Y-junction devices in the development of nanoelectronic components including inverters, logic gates, and frequency mixers. An electrical impedance model of a MWNT Y-junction will be presented which will help gain an understanding of the current transport mechanisms in these nanostructures. 1. P. Bandaru et al, ``Novel electrical switching behavior and logic in carbon nanotube Y-junctions'', Nature Materials, vol. 4(9), 663-666, (2005) 2. N. Gothard, et al. ``Controlled growth of Y-junction nanotubes using Ti-doped vapor catalyst'', Nanoletters 4, 213-217 (2004).

  8. 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

  9. Nanoscale Test Strips for Multiplexed Blood Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of our nanoscale test strips, or nanostrips, is to provide rapid, low-cost, powerful multiplexed analyses in a diminutive form so that whole body health...

  10. Tuning functional properties: From nanoscale building blocks to ...

    Indian Academy of Sciences (India)

    Tuning functional properties: From nanoscale building blocks to hybrid nanomaterials. K GEORGE THOMAS. Photosciences and Photonics Group, National Institute for Interdisciplinary Science and Technology (CSIR). (formerly Regional Research Laboratory), Trivandrum 695 019, India. and. Jawaharlal Nehru Centre for ...

  11. Strain effects on rotational property in nanoscale rotation system.

    Science.gov (United States)

    Huang, Jianzhang; Han, Qiang

    2018-01-11

    This paper presents a study of strain effects on nanoscale rotation system consists of double-walls carbon nanotube and graphene. It is found that the strain effects can be a real-time controlling method for nano actuator system. The strain effects on rotational property as well as the effect mechanism is studied systematically through molecular dynamics simulations, and it obtains valuable conclusions for engineering application of rotational property management of nanoscale rotation system. It founds that the strain effects tune the rotational property by influencing the intertube supporting effect and friction effect of double-walls carbon nanotube, which are two critical factors of rotational performance. The mechanism of strain effects on rotational property is investigated in theoretical level based on analytical model established through lattice dynamics theory. This work suggests great potentials of strain effects for nanoscale real-time control, and provides new ideas for design and application of real-time controllable nanoscale rotation system.

  12. Encapsulated tips for reliable nanoscale conduction in scanning probe technologies.

    Science.gov (United States)

    Bhaskaran, Harish; Sebastian, Abu; Drechsler, Ute; Despont, Michel

    2009-03-11

    Nanoscale tip apexes of conducting cantilever probes are important enablers for several conducting probe technologies that require reliable long-term operation, while preserving the nanoscale integrity of the tip apex. In this paper, the concept of an encapsulated tip with a nanoscale conducting core is presented. A method to fabricate such tips on conducting silicon microcantilevers is described. Long-term conduction and wear reliability of these nanoscale tips are evaluated systematically, and their ability to operate for sliding distances greater than 2 m in conduction and 11 m in wear on amorphous carbon is demonstrated. These results are expected to have an impact on the future of conducting probe-based technologies such as probe-based nanometrology, data storage and nanolithography.

  13. Integrated nanoscale tools for interrogating living cells

    Science.gov (United States)

    Jorgolli, Marsela

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

  14. WDM Nanoscale Laser Diodes for Si Photonic Interconnects

    Science.gov (United States)

    2016-07-25

    standard processing and stepper alignment for a bias current of only 2 mA. The small VCSEL can be coupled to multimode or single mode waveguides, and...mounting on silicon. The nanoscale VCSELs can achieve small optical modes and present a compact laser diode that is also robust. In this work we have used...The nanoscale VCSELs can achieve small optical modes and present a compact laser diode that is also robust. In this work we have used a lithographic

  15. Robust adaptive dynamic surface control of chaos in permanent magnet synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Du Qu [College of Physics and Electronic Engineering, Guangxi Normal University, Guilin 541004 (China); Luo, Xiao Shu [College of Physics and Electronic Engineering, Guangxi Normal University, Guilin 541004 (China)]. E-mail: lxs@mailbox.gxnu.edu.cn; Wang, Bing Hong [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Fang, Jin Qing [China Institute of Atomic Energy, Beijing 102413 (China)

    2007-03-19

    With system parameters falling into a certain area, the permanent magnet synchronous motor (PMSM) is experiencing chaotic behavior which threatens the secure and stable operation of drive system. To control the undesirable chaos in PMSM, an adaptive dynamic surface control (DSC) law is first designed, which overcomes the problem of 'explosion of terms' associated with the traditional backstepping design procedure by introducing first-order low-pass filters. And then, based on Lyapunov asymptotical stability theory, stability of the closed-loop controlled system is analyzed. Simulation results show that the presented control law is very effective and robust against the uncertainties in system parameters. The research of this Letter may help to maintain the industrial drive system's security operation.

  16. Adaptive fuzzy dynamic surface control for the chaotic permanent magnet synchronous motor using Nussbaum gain

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shaohua [School of Automation, Chongqing University, Chongqing 400044, China and College of Mechanical Engineering, Hunan University of Arts and Science, Hunan 415000 (China)

    2014-09-01

    This paper is concerned with the problem of adaptive fuzzy dynamic surface control (DSC) for the permanent magnet synchronous motor (PMSM) system with chaotic behavior, disturbance and unknown control gain and parameters. Nussbaum gain is adopted to cope with the situation that the control gain is unknown. And the unknown items can be estimated by fuzzy logic system. The proposed controller guarantees that all the signals in the closed-loop system are bounded and the system output eventually converges to a small neighborhood of the desired reference signal. Finally, the numerical simulations indicate that the proposed scheme can suppress the chaos of PMSM and show the effectiveness and robustness of the proposed method.

  17. Modeling and Extended State Observer Based Dynamic Surface Control for Cold Rolling Mill System

    Directory of Open Access Journals (Sweden)

    Xu Li

    2016-01-01

    Full Text Available The modeling and control problems are investigated for cold rolling mill system. Firstly, we establish a monitor automatic gauge control (MAGC model for a practical cold rolling mill system. The new model is with mismatched uncertainties. Then, an extended state observer (ESO is developed to estimate uncertainties. In the general high-order systems, the ESO is also used to estimate states. By dynamic surface control method, we design the controller to guarantee stabilization of the cold rolling mill system. Furthermore, we extend proposed method to general high-order systems, in which we analyze the difference from cold rolling mill system. Finally, simulation results for MAGC system are presented to demonstrate the effectiveness of the proposed control strategy.

  18. Neural network-based adaptive dynamic surface control for permanent magnet synchronous motors.

    Science.gov (United States)

    Yu, Jinpeng; Shi, Peng; Dong, Wenjie; Chen, Bing; Lin, Chong

    2015-03-01

    This brief considers the problem of neural networks (NNs)-based adaptive dynamic surface control (DSC) for permanent magnet synchronous motors (PMSMs) with parameter uncertainties and load torque disturbance. First, NNs are used to approximate the unknown and nonlinear functions of PMSM drive system and a novel adaptive DSC is constructed to avoid the explosion of complexity in the backstepping design. Next, under the proposed adaptive neural DSC, the number of adaptive parameters required is reduced to only one, and the designed neural controllers structure is much simpler than some existing results in literature, which can guarantee that the tracking error converges to a small neighborhood of the origin. Then, simulations are given to illustrate the effectiveness and potential of the new design technique.

  19. Adaptive fuzzy dynamic surface control for the chaotic permanent magnet synchronous motor using Nussbaum gain.

    Science.gov (United States)

    Luo, Shaohua

    2014-09-01

    This paper is concerned with the problem of adaptive fuzzy dynamic surface control (DSC) for the permanent magnet synchronous motor (PMSM) system with chaotic behavior, disturbance and unknown control gain and parameters. Nussbaum gain is adopted to cope with the situation that the control gain is unknown. And the unknown items can be estimated by fuzzy logic system. The proposed controller guarantees that all the signals in the closed-loop system are bounded and the system output eventually converges to a small neighborhood of the desired reference signal. Finally, the numerical simulations indicate that the proposed scheme can suppress the chaos of PMSM and show the effectiveness and robustness of the proposed method.

  20. Confined Chemical Etching for Electrochemical Machining with Nanoscale Accuracy.

    Science.gov (United States)

    Zhan, Dongping; Han, Lianhuan; Zhang, Jie; Shi, Kang; Zhou, Jian-Zhang; Tian, Zhao-Wu; Tian, Zhong-Qun

    2016-11-15

    In the past several decades, electrochemical machining (ECM) has enjoyed the reputation of a powerful technique in the manufacturing industry. Conventional ECM methods can be classified as electrolytic machining and electroforming: the former is based on anodic dissolution and the latter is based on cathodic deposition of metallic materials. Strikingly, ECM possesses several advantages over mechanical machining, such as high removal rate, the capability of making complex three-dimensional structures, and the practicability for difficult-to-cut materials. Additionally, ECM avoids tool wear and thermal or mechanical stress on machining surfaces. Thus, ECM is widely used for various industrial applications in the fields of aerospace, automobiles, electronics, etc. Nowadays, miniaturization and integration of functional components are becoming significant in ultralarge scale integration (ULSI) circuits, microelectromechanical systems (MEMS), and miniaturized total analysis systems (μ-TAS). As predicted by Moore's law, the feature size of interconnectors in ULSI circuits are down to several nanometers. In this Account, we present our perseverant research in the last two decades on how to "confine" the ECM processes to occur at micrometer or even nanometer scale, that is, to ensure ECM with nanoscale accuracy. We have been developing the confined etchant layer technique (CELT) to fabricate three-dimensional micro- and nanostructures (3D-MNS) on different metals and semiconductor materials since 1992. In general, there are three procedures in CELT: (1) generating the etchant on the surface of the tool electrode by electrochemical or photoelectrochemical reactions; (2) confining the etchant in a depleted layer with a thickness of micro- or nanometer scale; (3) feeding the tool electrode to etch the workpiece. Scavengers, which can react with the etchant, are usually adopted to form a confined etchant layer. Through the subsequent homogeneous reaction between the scavenger

  1. Engineering multiple topological phases in nanoscale Van der Waals heterostructures: realisation of α-antimonene

    Science.gov (United States)

    Märkl, T.; Kowalczyk, P. J.; Le Ster, M.; Mahajan, I. V.; Pirie, H.; Ahmed, Z.; Bian, G.; Wang, X.; Chiang, T.-C.; Brown, S. A.

    2018-01-01

    Van der Waals heterostructures have recently been identified as providing many opportunities to create new two-dimensional materials, and in particular to produce materials with topologically-interesting states. Here we show that it is possible to create such heterostructures with multiple topological phases in a single nanoscale island. We discuss their growth within the framework of diffusion-limited aggregation, the formation of moiré patterns due to the differing crystallographies of the materials comprising the heterostructure, and the potential to engineer both the electronic structure as well as local variations of topological order. In particular we show that it is possible to build islands which include both the hexagonal β- and rectangular α-forms of antimonene, on top of the topological insulator α-bismuthene. This is the first experimental realisation of α-antimonene, and we show that it is a topologically non-trivial material in the quantum spin Hall class.

  2. Nanoscale artificial antigen presenting cells for T cell immunotherapy.

    Science.gov (United States)

    Perica, Karlo; De León Medero, Andrés; Durai, Malarvizhi; Chiu, Yen Ling; Bieler, Joan Glick; Sibener, Leah; Niemöller, Michaela; Assenmacher, Mario; Richter, Anne; Edidin, Michael; Oelke, Mathias; Schneck, Jonathan

    2014-01-01

    Artificial antigen presenting cells (aAPC), which deliver stimulatory signals to cytotoxic lymphocytes, are a powerful tool for both adoptive and active immunotherapy. Thus far, aAPC have been synthesized by coupling T cell activating proteins such as CD3 or MHC-peptide to micron-sized beads. Nanoscale platforms have different trafficking and biophysical interaction properties and may allow development of new immunotherapeutic strategies. We therefore manufactured aAPC based on two types of nanoscale particle platforms: biocompatible iron-dextran paramagnetic particles (50-100 nm in diameter) and avidin-coated quantum dot nanocrystals (~30 nm). Nanoscale aAPC induced antigen-specific T cell proliferation from mouse splenocytes and human peripheral blood T cells. When injected in vivo, both iron-dextran particles and quantum dot nanocrystals enhanced tumor rejection in a subcutaneous mouse melanoma model. This is the first description of nanoscale aAPC that induce antigen-specific T cell proliferation in vitro and lead to effective T cell stimulation and inhibition of tumor growth in vivo. Artifical antigen presenting cells could revolutionize the field of cancer-directed immunotherapy. This team of investigators have manufactured two types of nanoscale particle platform-based aAPCs and demonstrates that both iron-dextran particles and quantum dot nanocrystals enhance tumor rejection in a melanoma model, providing the first description of nanoscale aAPCs that lead to effective T cell stimulation and inhibition of tumor growth. © 2013.

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

    Science.gov (United States)

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

    2017-02-01

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

  4. Nanoscale SOI silicon light source design for improved efficiency

    Science.gov (United States)

    Venter, Petrus J.; du Plessis, Monuko; Bogalecki, Alfons W.; Janse van Rensburg, Christo

    2013-03-01

    Silicon-on-insulator (SOI) is becoming an important technology platform in nanometer scale CMOS integrated circuits. The platform offers a number of distinct advantages over bulk CMOS for materializing silicon light sources based on hot carrier luminescence. This work describes the design of nanoscale silicon structures for enhanced light emission with improved power efficiency, which allows the use of SOI light sources in short-haul optical communication links with extended possibilities for other applications. It has been shown experimentally that reducing the dimensions of the active material results in an improvement of electroluminescent power emitted from forward-biased pn-junctions. Previously published results show a similar trend for light sources based on hot carrier luminescence. Building on our previous work in SOI light sources, multiple fingerlike junctions are manufactured in an arrayed fashion for coupling into large diameter core optical fibers for CMOS optical communications up to a few hundred meters. The manufacturing methodology and associated challenges are discussed for the scaling down of device dimensions, and difficulties in realizing the structures are investigated. The optical power characteristics are discussed as well as the spectral nature of emission along with the advantages and disadvantages thereof. This work compares different architectures of light sources that were implemented where a comparison is drawn between previous SOI devices as well as bulk CMOS. We believe the improved SOI light sources are fully compatible with modern CMOS technologies based on SOI and may provide such technologies with a much needed light source as part of the circuit designer's toolkit.

  5. PREFACE: Nanoscale Devices and System Integration Conference (NDSI-2004)

    Science.gov (United States)

    Khizroev, Sakhrat; Litvinov, Dmitri

    2004-10-01

    The inaugural conference on Nanoscale Devices and System Integration (NDSI-2004) was held in Miami, Florida, 15-19 February, 2004. The focus of the conference was `real-life' devices and systems that have recently emerged as a result of various nanotechnology initiatives in chemistry and chemical engineering, physics, electrical engineering, materials science and engineering, biomedical engineering, computer science, robotics, and environmental science. The conference had a single session all-invited speaker format, with the presenters making the `Who's Who in Nanotechnology' list. Contributed work was showcased at a special poster session. The conference, sponsored by the Institute of Electrical and Electronics Engineers (IEEE) and the US Air Force, and endorsed by Materials Research Society (MRS), drew more than 160 participants from fourteen countries. To strengthen the connection between fundamental research and `real-life' applications, the conference featured a large number of presenters from both academia and industry. Among the participating companies were NEC, IBM, Toshiba, AMD, Samsung, Seagate, and Veeco. Nanotechnology has triggered a new wave of research collaborations between researchers from academia and industry with a broad range of specializations. Such a global approach has resulted in a number of breakthrough accomplishments. One of the main goals of this conference was to identify these accomplishments and put the novel technology initiatives and the emerging research teams on the map. Among the key nanotechnology applications demonstrated at NDSI-2004 were carbon-nanotube-based transistors, quantum computing systems, nanophotonic devices, single-molecule electronic devices and biological magnetic sources. Due to the unprecedented success of the conference, the organizing committee of NDSI has unanimously chosen to turn NDSI into an annual international nanotechnology event. The next NDSI is scheduled for 4-6 April, 2005, in Houston, Texas

  6. Study of dislocations in nanoscale semiconductors by ab initio molecular dynamics and lattice Green's function methods

    Energy Technology Data Exchange (ETDEWEB)

    Masuda-Jindo, K. [Department of Materials Science and Engineering, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hung, Vu Van [Hanoi National Pedagogic University, km8 Hanoi-Sontay Highway, Hanoi (Viet Nam); Menon, M. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States)

    2005-04-01

    The electronic and mechanical properties of the nanoscale materials are studied by using an ab initio molecular dynamics (TBMD) method and temperature dependent lattice Green's function method. The core structures of dislocations in semiconductor crystallites composed of {proportional_to}1000 atoms are calculated using the ab initio TB molecular dynamics method and compared with those in the corresponding bulk semiconductors. The core structures of both 30 and 90 partial dislocations in Si crystallites are found to be similar to those of the bulk Si crystals, but excess energies of the dislocations are of considerably smaller in the small semiconductor crystallites. We also investigate the mechanical (dislocation) properties of carbon related nanoscale materials, graphen in comparison with CNT, by using the temperature dependent Lattice Green's function method and we will show that the thermodynamic and mechanical properties of the nanoscale materials are quite different from those of the corresponding bulk materials. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Non-resonant Nanoscale Extreme Light Confinement

    Energy Technology Data Exchange (ETDEWEB)

    Subramania, Ganapathi Subramanian [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Huber, Dale L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    A wide spectrum of photonics activities Sandia is engaged in such as solid state lighting, photovoltaics, infrared imaging and sensing, quantum sources, rely on nanoscale or ultrasubwavelength light-matter interactions (LMI). The fundamental understanding in confining electromagnetic power and enhancing electric fields into ever smaller volumes is key to creating next generation devices for these programs. The prevailing view is that a resonant interaction (e.g. in microcavities or surface-plasmon polaritions) is necessary to achieve the necessary light confinement for absorption or emission enhancement. Here we propose new paradigm that is non-resonant and therefore broadband and can achieve light confinement and field enhancement in extremely small areas [~(λ/500)^2 ]. The proposal is based on a theoretical work[1] performed at Sandia. The paradigm structure consists of a periodic arrangement of connected small and large rectangular slits etched into a metal film named double-groove (DG) structure. The degree of electric field enhancement and power confinement can be controlled by the geometry of the structure. The key operational principle is attributed to quasistatic response of the metal electrons to the incoming electromagnetic field that enables non-resonant broadband behavior. For this exploratory LDRD we have fabricated some test double groove structures to enable verification of quasistatic electronic response in the mid IR through IR optical spectroscopy. We have addressed some processing challenges in DG structure fabrication to enable future design of complex sensor and detector geometries that can utilize its non-resonant field enhancement capabilities.].

  8. Nanotechnology and Nanoscale Science: Educational challenges

    Science.gov (United States)

    Jones, M. Gail; Blonder, Ron; Gardner, Grant E.; Albe, Virginie; Falvo, Michael; Chevrier, Joel

    2013-06-01

    Nanotechnology has been touted as the next 'industrial revolution' of our modern age. In order for successful research, development, and social discourses to take place in this field, education research is needed to inform the development of standards, course development, and workforce preparation. In addition, there is a growing need to educate citizens and students about risks, benefits, and social and ethical issues related to nanotechnology. This position paper describes the advancements that have been made in nanoscale science and nanotechnology, and the challenges that exist to educate students and the public about critical nanoscience concepts. This paper reviews the current research on nanotechnology education including curricula, educational programs, informal education, and teacher education. Furthermore, the unique risks, benefits and ethics of these unusual technological applications are described in relation to nanoeducation goals. Finally, we outline needed future research in the areas of nanoscience content, standards and curricula, nanoscience pedagogy, teacher education, and the risks, benefits, and social and ethical dimensions for education in this emerging field.

  9. 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.

  10. 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.

  11. Sulfidation of Cadmium at the Nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Cabot, Andreu; Smith, Rachel; Yin, Yadong; Zheng, Haimei; Reinhard, Bjorn; Liu, Haitao; Alivisatos, A. Paul

    2008-05-22

    We investigate the evolution of structures that result when spherical Cd nanoparticles of a few hundred nanometers in diameter react with dissolved molecular sulfur species in solution to form hollow CdS. Over a wide range of temperatures and concentrations, we find that rapid Cd diffusion through the growing CdS shell localizes the reaction front at the outermost CdS/S interface, leading to hollow particles when all the Cd is consumed. When we examine partially reacted particles, we find that this system differs significantly from others in which the nanoscale Kirkendall effect has been used to create hollow particles. In previously reported systems, partial reaction creates a hollow particle with a spherically symmetric metal core connected to the outer shell by filaments. In contrast, here we obtain a lower symmetry structure, in which the unreacted metal core and the coalesced vacancies separate into two distinct spherical caps, minimizing the metal/void interface. This pattern of void coalescence is likely to occur in situations where the metal/vacancy self-diffusivities in the core are greater than the diffusivity of the cations through the shell.

  12. 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.

  13. Nonlinear ultrasound imaging of nanoscale acoustic biomolecules

    Science.gov (United States)

    Maresca, David; Lakshmanan, Anupama; Lee-Gosselin, Audrey; Melis, Johan M.; Ni, Yu-Li; Bourdeau, Raymond W.; Kochmann, Dennis M.; Shapiro, Mikhail G.

    2017-02-01

    Ultrasound imaging is widely used to probe the mechanical structure of tissues and visualize blood flow. However, the ability of ultrasound to observe specific molecular and cellular signals is limited. Recently, a unique class of gas-filled protein nanostructures called gas vesicles (GVs) was introduced as nanoscale (˜250 nm) contrast agents for ultrasound, accompanied by the possibilities of genetic engineering, imaging of targets outside the vasculature and monitoring of cellular signals such as gene expression. These possibilities would be aided by methods to discriminate GV-generated ultrasound signals from anatomical background. Here, we show that the nonlinear response of engineered GVs to acoustic pressure enables selective imaging of these nanostructures using a tailored amplitude modulation strategy. Finite element modeling predicted a strongly nonlinear mechanical deformation and acoustic response to ultrasound in engineered GVs. This response was confirmed with ultrasound measurements in the range of 10 to 25 MHz. An amplitude modulation pulse sequence based on this nonlinear response allows engineered GVs to be distinguished from linear scatterers and other GV types with a contrast ratio greater than 11.5 dB. We demonstrate the effectiveness of this nonlinear imaging strategy in vitro, in cellulo, and in vivo.

  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. Non-Equilibrium Nanoscale Self-Organization

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Michael J

    2006-03-09

    Self-organized one- and two-dimensional arrays of nanoscale surface features ("ripples" and "dots") sometimes form spontaneously on initially flat surfaces eroded by a directed ion beam in a process called "sputter patterning". Experiments on this sputter patterning process with focused and unfocused ion beams, combined with theoretical advances, have been responsible for a number of scientific advances. Particularly noteworthy are (i) the discovery of propagative, rather than dissipative, behavior under some ion erosion conditions, permitting a pattern to be fabricated at a large length scale and propagated over large distances while maintaining, or even sharpening, the sharpest features; (ii) the first demonstration of guided self-organization of sputter patterns, along with the observation that defect density is minimized when the spacing between boundaries is near an integer times the natural spatial period; and (iii) the discovery of metastability of smooth surfaces, which contradicts the nearly universally accepted linear stability theory that predicts that any surface is linearly unstable to sinusoidal perturbations of some wave vector.

  16. The Soft Mode Driven Dynamics in Ferroelectric Perovskites at the Nanoscale: An Atomistic Study

    Science.gov (United States)

    McCash, Kevin

    The discovery of ferroelectricity at the nanoscale has incited a lot of interest in perovskite ferroelectrics not only for their potential in device application but also for their potential to expand fundamental understanding of complex phenomena at very small size scales. Unfortunately, not much is known about the dynamics of ferroelectrics at this scale. Many of the widely held theories for ferroelectric materials are based on bulk dynamics which break down when applied to smaller scales. In an effort to increase understanding of nanoscale ferroelectric materials we use atomistic resolution computational simulations to investigate the dynamics of polar perovskites. Within the framework of a well validated effective Hamiltonian model we are able to accurately predict many of the properties of ferroelectric materials at the nanoscale including the response of the soft mode to mechanical boundary conditions and the polarization reversal dynamics of ferroelectric nanowires. Given that the focus of our study is the dynamics of ferroelectric perovskites we begin by developing an effective Hamiltonian based model that could simultaneously describe both static and dynamic properties of such materials. Our study reveals that for ferroelectric perovskites that undergo a sequence of phase transitions, such as BaTiO3. for example, the minimal parameter effective Hamiltonian model is unable to reproduce both static and dynamical properties simultaneously. Nevertheless we developed two sets of parameters that accurately describes the static properties and dynamic properties of BaTiO3 independently. By creating a tool that accurately models the dynamical properties of perovskite ferroelectrics we are able to investigate the frequencies of the soft modes in the perovskite crystal. The lowest energy transverse optical soft modes in perovskite ferroelectrics are known to be cause of the ferroelectric phase transition in these materials and affect a number of electrical properties

  17. Nanoscale Plasmonic Devices Based on Metal-Dielectric-Metal Stub Resonators

    Directory of Open Access Journals (Sweden)

    Yin Huang

    2012-01-01

    Full Text Available We review some of the recent research activities on plasmonic devices based on metal-dielectric-metal (MDM stub resonators for manipulating light at the nanoscale. We first introduce slow-light subwavelength plasmonic waveguides based on plasmonic analogues of periodically loaded transmission lines and electromagnetically induced transparency. In both cases, the structures consist of a MDM waveguide side-coupled to periodic arrays of MDM stub resonators. We then introduce absorption switches consisting of a MDM plasmonic waveguide side-coupled to a MDM stub resonator filled with an active material.

  18. Nano-Scale Characterization of a Piezoelectric Polymer (Polyvinylidene Difluoride, PVDF

    Directory of Open Access Journals (Sweden)

    Rodrigo Cooper

    2008-11-01

    Full Text Available The polymer polyvinylidene difluoride (PVDF has unique piezoelectric properties favorable for Micro-Electro-Mechanical Systems (MEMS and Nano-Electro-Mechanical Systems (NEMS applications. In the present research, we conducted nanometer-length scale characterization of this material using several high-resolution techniques. Specifically, we used an atomic force microscope (AFM to study the nanoand microstructures of the PVDF under stress and to measure their nanoscale conductivity and piezoelectricity. We found that the surface morphology, electronic structure, and microstructure are profoundly affected under electrical potential. Such a behavior is important for the properties and performance of MEMS and NEMS.

  19. Department of Energy Nanoscale Science Research Centers: Approach to Nanomaterial ES&H

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2008-05-12

    The following non-mandatory guidance is intended for the Nanoscale Science Research Centers (NSRCs) funded by the Basic Energy Sciences program office under the U.S. Department of Energy's Office of Science. It describes practices thought appropriate to the management of environmental, safety and health (ES&H) concerns associated with laboratory-scale operations involving the design, synthesis, or characterization of engineered nanomaterials, In general, it is intended to apply to precursors, intermediates, and wastes used during, or resulting from synthesizing such nanomaterials. In general, it is not intended to apply to materials for which an occupational exposure limit has been established.

  20. Ferroelectricity at the nanoscale basics and applications

    CERN Document Server

    Fridkin, Vladimir

    2014-01-01

    This book examines a wide range of ferroelectric materials. It explains the theoretical background of ultrathin ferroelectric films,  presents applications of ferroelectric materials, and displays the mechanism of switching of nanosized ferroelectric films.

  1. 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

  2. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.

    2011-02-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

  3. Effects of Loading Frequency and Film Thickness on the Mechanical Behavior of Nanoscale TiN Film

    Science.gov (United States)

    Liu, Jin-na; Xu, Bin-shi; Wang, Hai-dou; Cui, Xiu-fang; Jin, Guo; Xing, Zhi-guo

    2017-09-01

    The mechanical properties of a nanoscale-thickness film material determine its reliability and service life. To achieve quantitative detection of film material mechanical performance based on nanoscale mechanical testing methods and to explore the influence of loading frequency of the cycle load on the fatigue test, a TiN film was prepared on monocrystalline silicon by magnetron sputtering. The microstructure of the nanoscale-thickness film material was characterized by using scanning electron microscopy and high-resolution transmission electron microscopy. The residual stress distribution of the thin film was obtained by using an electronic film stress tester. The hardness values and the fatigue behavior were measured by using a nanomechanical tester. Combined with finite element simulation, the paper analyzed the influence of the film thickness and loading frequency on the deformation, as well as the equivalent stress and strain. The results showed that the TiN film was a typical face-centered cubic structure with a large amount of amorphous. The residual compressive stress decreased gradually with increasing thin film thickness, and the influence of the substrate on the elastic modulus and hardness was also reduced. A greater load frequency would accelerate the dynamic fatigue damage that occurs in TiN films.

  4. Nanoscale Charge Balancing Mechanism in Alkali Substituted Calcium-Silicate-Hydrate Gels

    CERN Document Server

    Özçelik, V Ongun

    2016-01-01

    Alkali-activated materials and related alternative cementitious systems are sustainable material technologies that have the potential to substantially lower CO$_2$ emissions associated with the construction industry. However, the impact of augmenting the chemical composition of the material on the main binder phase, calcium-silicate-hydrate gel, is far from understood, particularly since this binder phase is disordered at the nanoscale. Here, we reveal the presence of a charge balancing mechanism at the molecular level, which leads to stable structures when alkalis (i.e., Na or K) are incorporated into a calcium-silicate-hydrate gel, as modeled using crystalline 14{\\AA} tobermorite. These alkali containing charge balanced structures possess superior mechanical properties compared to their charge unbalanced counterparts. Our results, which are based on first-principles simulations using density functional theory, include the impact of charge balancing on the optimized geometries of the new model phases, format...

  5. On the emergence of Raman signals characterizing multicenter nanoscale interactions

    Science.gov (United States)

    Williams, Mathew D.; Bradshaw, David S.; Andrews, David L.

    2016-04-01

    Raman scattering is most commonly associated with a change in vibrational state within one molecule, with signals in the corresponding spectrum widely used to identify material structures. When the corresponding theory is developed using quantum electrodynamics, the fundamental scattering process is described by a single photon of one radiation mode being annihilated with the concurrent creation of another photon; the two photon energies differ by an amount corresponding to the transfer of vibrational energy within the system. Here, we consider nanoscale interactions between neighboring molecules to mediate the process, by way of a virtual photon exchange to connect the evolution of the two molecular states. We consider both a single and pair of virtual photon exchanges. Our analysis deploys two realistic assumptions: in each pairwise interaction the two components are considered to be (i) chemically different and (ii) held in a fixed orientation with respect to each other, displaced by an amount equivalent to the near-field region; resulting in higher order dependences on displacement R becoming increasingly significant, and at the limit the short-range R-6 term can even dominate over R-3 dependence. In our investigation one center undergoes a change in vibrational energy; each neighboring molecule returns to the electronic and vibrational state in which it began. For the purposes of providing results, a Stokes transition has been assumed; analogous principles hold for the anti-Stokes counterpart. Experimentally, there is no change to the dependence on the intensity of laser light. However, the various mechanisms presented herein lead to different selection rules applying in each instance. In some cases specifically identifiable mechanisms will be active for a given transition, leading to new and characteristic lines in the Raman spectrum. A thorough investigation of all physically achievable mechanisms will be detailed in this work.

  6. Surface control of cold hibernated elastic memory self-deployable structure

    Science.gov (United States)

    Sokolowski, Witold; Ghaffarian, Reza

    2006-03-01

    A new class of simple, reliable, lightweight, low packaging volume and cost, self-deployable structures has been developed for use in space and commercial applications. This technology called "cold hibernated elastic memory" (CHEM) utilizes shape memory polymers (SMP) in open cellular (foam) structure or sandwich structures made of shape memory polymer foam cores and polymeric composite skins. Some of many potential CHEM space applications require a high precision deployment and surface accuracy during operation. However, a CHEM structure could be slightly distorted by the thermo-mechanical processing as well as by thermal space environment. Therefore, the sensor system is desirable to monitor and correct the potential surface imperfection. During these studies, the surface control of CHEM smart structures was demonstrated using a Macro-Fiber Composite (MFC) actuator developed by the NASA LaRC and US Army ARL. The test results indicate that the MFC actuator performed well before and after processing cycles. It reduced some residue compressive strain that in turn corrected very small shape distortion after each processing cycle. The integrated precision strain gages were detecting only a small flat shape imperfection indicating a good recoverability of original shape of the CHEM test structure.

  7. An Adaptive Dynamic Surface Controller for Ultralow Altitude Airdrop Flight Path Angle with Actuator Input Nonlinearity

    Directory of Open Access Journals (Sweden)

    Mao-long Lv

    2016-01-01

    Full Text Available In the process of ultralow altitude airdrop, many factors such as actuator input dead-zone, backlash, uncertain external atmospheric disturbance, and model unknown nonlinearity affect the precision of trajectory tracking. In response, a robust adaptive neural network dynamic surface controller is developed. As a result, the aircraft longitudinal dynamics with actuator input nonlinearity is derived; the unknown nonlinear model functions are approximated by means of the RBF neural network. Also, an adaption strategy is used to achieve robustness against model uncertainties. Finally, it has been proved that all the signals in the closed-loop system are bounded and the tracking error converges to a small residual set asymptotically. Simulation results demonstrate the perfect tracking performance and strong robustness of the proposed method, which is not only applicable to the actuator with input dead-zone but also suitable for the backlash nonlinearity. At the same time, it can effectively overcome the effects of dead-zone and the atmospheric disturbance on the system and ensure the fast track of the desired flight path angle instruction, which overthrows the assumption that system functions must be known.

  8. Output Feedback Adaptive Dynamic Surface Control of Permanent Magnet Synchronous Motor with Uncertain Time Delays via RBFNN

    Directory of Open Access Journals (Sweden)

    Shaohua Luo

    2014-01-01

    Full Text Available This paper focuses on an adaptive dynamic surface control based on the Radial Basis Function Neural Network for a fourth-order permanent magnet synchronous motor system wherein the unknown parameters, disturbances, chaos, and uncertain time delays are presented. Neural Network systems are used to approximate the nonlinearities and an adaptive law is employed to estimate accurate parameters. Then, a simple and effective controller has been obtained by introducing dynamic surface control technique on the basis of first-order filters. Asymptotically tracking stability in the sense of uniformly ultimate boundedness is achieved in a short time. Finally, the performance of the proposed control has been illustrated through simulation results.

  9. The relationship between nanoscale architecture and function in photovoltaic multichromophoric arrays as visualized by Kelvin probe force microscopy.

    Science.gov (United States)

    Palermo, Vincenzo; Otten, Matthijs B J; Liscio, Andrea; Schwartz, Erik; de Witte, Pieter A J; Castriciano, Maria Angela; Wienk, Martijn M; Nolde, Fabian; De Luca, Giovanna; Cornelissen, Jeroen J L M; Janssen, René A J; Müllen, Klaus; Rowan, Alan E; Nolte, Roeland J M; Samorì, Paolo

    2008-11-05

    The physicochemical properties of organic (multi)component films for optoelectronic applications depend on both the mesoscopic and nanoscale architectures within the semiconducting material. Two main classes of semiconducting materials are commonly used: polymers and (liquid) crystals of small aromatic molecules. Whereas polymers (e.g., polyphenylenevinylenes and polythiophenes) are easy to process in solution in thin and uniform layers, small molecules can form highly defined (liquid) crystals featuring high charge mobilities. Herein, we combine the two material types by employing structurally well-defined polyisocyanopeptide polymers as scaffolds to precisely arrange thousands of electron-accepting molecules, namely, perylenebis(dicarboximides) (PDIs), in defined chromophoric wires with lengths of hundreds of nanometers. The polymer backbone enforces high control over the spatial location of PDI dyes, favoring both enhanced exciton and charge transfer. When blended with an electron-donor system such as regioregular poly(3-hexylthiophene), this polymeric PDI shows a relative improvement in charge generation and diffusion with respect to monomeric, aggregated PDI. In order to correlate this enhanced behavior with respect to the architecture, atomic force microscopy investigations on the mixtures were carried out. These studies revealed that the two polymers form interpenetrated bundles having a nanophase-segregated character and featuring a high density of contact points between the two different phases. In order to visualize the relationship between the architecture and the photovoltaic efficiency, Kelvin probe force microscopy measurements were carried out on submonolayer-thick films. This technique allowed for the first time the direct visualization of the photovoltaic activity occurring in such a nanoscale phase-segregated ultrathin film with true nanoscale spatial resolution, thus making possible a study of the correlation between function and architecture

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

    Directory of Open Access Journals (Sweden)

    Jia-Yang Juang

    2016-10-01

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

  11. 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.

  12. 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

  13. Nanoscale Surface Plasmonics Sensor With Nanofluidic Control

    Science.gov (United States)

    Wei, Jianjun; Singhal, Sameer; Waldeck, David H.; Kofke, Matthew

    2013-01-01

    Conventional quantitative protein assays of bodily fluids typically involve multiple steps to obtain desired measurements. Such methods are not well suited for fast and accurate assay measurements in austere environments such as spaceflight and in the aftermath of disasters. Consequently, there is a need for a protein assay technology capable of routinely monitoring proteins in austere environments. For example, there is an immediate need for a urine protein assay to assess astronaut renal health during spaceflight. The disclosed nanoscale surface plasmonics sensor provides a core detection method that can be integrated to a lab-on-chip device that satisfies the unmet need for such a protein assay technology. Assays based upon combinations of nanoholes, nanorings, and nanoslits with transmission surface plasmon resonance (SPR) are used for assays requiring extreme sensitivity, and are capable of detecting specific analytes at concentrations as low as picomole to femtomole level in well-controlled environments. The device operates in a transmission mode configuration in which light is directed at one planar surface of the array, which functions as an optical aperture. The incident light induces surface plasmon light transmission from the opposite surface of the array. The presence of a target analyte is detected by changes in the spectrum of light transmitted by the array when a target analyte induces a change in the refractive index of the fluid within the nanochannels. This occurs, for example, when a target analyte binds to a receptor fixed to the walls of the nanochannels in the array. Independent fluid handling capability for individual nanoarrays on a nanofluidic chip containing a plurality of nanochannel arrays allows each array to be used to sense a different target analyte and/or for paired arrays to analyze control and test samples simultaneously in parallel. The present invention incorporates transmission mode nanoplasmonics and nanofluidics into a single

  14. 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.

  15. Temperature mapping of operating nanoscale devices by scanning probe thermometry

    Science.gov (United States)

    Menges, Fabian; Mensch, Philipp; Schmid, Heinz; Riel, Heike; Stemmer, Andreas; Gotsmann, Bernd

    2016-03-01

    Imaging temperature fields at the nanoscale is a central challenge in various areas of science and technology. Nanoscopic hotspots, such as those observed in integrated circuits or plasmonic nanostructures, can be used to modify the local properties of matter, govern physical processes, activate chemical reactions and trigger biological mechanisms in living organisms. The development of high-resolution thermometry techniques is essential for understanding local thermal non-equilibrium processes during the operation of numerous nanoscale devices. Here we present a technique to map temperature fields using a scanning thermal microscope. Our method permits the elimination of tip-sample contact-related artefacts, a major hurdle that so far has limited the use of scanning probe microscopy for nanoscale thermometry. We map local Peltier effects at the metal-semiconductor contacts to an indium arsenide nanowire and self-heating of a metal interconnect with 7 mK and sub-10 nm spatial temperature resolution.

  16. Flexible nanoscale high-performance FinFETs

    KAUST Repository

    Sevilla, Galo T.

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics.

  17. Nanoscale control of heat generation with plasmonic nanostructures

    OpenAIRE

    Morales Dalmau, Jordi

    2013-01-01

    [ANGLÈS] During the last 25 years nanotechnology has become a transvers field either in research and everyday's live. In this work we present a method which can control temperature down to nanoscale thanks to plasmonic properties of gold nanoparticles. Moreover, we open a new field named "thermal engineering" which has the aim of performing adaptable thermal maps for every purpose at nanoscale. [CASTELLÀ] Durante los últimos 25 años la nanotecnología se ha situado como un importante campo ...

  18. Electroanalytical Ventures at Nanoscale Interfaces Between Immiscible Liquids.

    Science.gov (United States)

    Arrigan, Damien W M; Liu, Yang

    2016-06-12

    Ion transfer at the interface between immiscible electrolyte solutions offers many benefits to analytical chemistry, including the ability to detect nonredox active ionized analytes, to detect ions whose redox electrochemistry is accompanied by complications, and to separate ions based on electrocontrolled partition. Nanoscale miniaturization of such interfaces brings the benefits of enhanced mass transport, which in turn leads to improved analytical performance in areas such as sensitivity and limits of detection. This review discusses the development of such nanoscale interfaces between immiscible liquids and examines the analytical advances that have been made to date, including prospects for trace detection of ion concentrations.

  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

    We address the formation and characterisation of three different nanoscale systems on single-crystal Au(lll) electrode surfaces in aqueous electrolyte solutions. The systems are investigated particularly by single-crystal electrochernistry and in situ scanning tunnelling rnicroscopy (STM). The [mt...... 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. Learning from adaptive neural dynamic surface control of strict-feedback systems.

    Science.gov (United States)

    Wang, Min; Wang, Cong

    2015-06-01

    Learning plays an essential role in autonomous control systems. However, how to achieve learning in the nonstationary environment for nonlinear systems is a challenging problem. In this paper, we present learning method for a class of n th-order strict-feedback systems by adaptive dynamic surface control (DSC) technology, which achieves the human-like ability of learning by doing and doing with learned knowledge. To achieve the learning, this paper first proposes stable adaptive DSC with auxiliary first-order filters, which ensures the boundedness of all the signals in the closed-loop system and the convergence of tracking errors in a finite time. With the help of DSC, the derivative of the filter output variable is used as the neural network (NN) input instead of traditional intermediate variables. As a result, the proposed adaptive DSC method reduces greatly the dimension of NN inputs, especially for high-order systems. After the stable DSC design, we decompose the stable closed-loop system into a series of linear time-varying perturbed subsystems. Using a recursive design, the recurrent property of NN input variables is easily verified since the complexity is overcome using DSC. Subsequently, the partial persistent excitation condition of the radial basis function NN is satisfied. By combining a state transformation, accurate approximations of the closed-loop system dynamics are recursively achieved in a local region along recurrent orbits. Then, the learning control method using the learned knowledge is proposed to achieve the closed-loop stability and the improved control performance. Simulation studies are performed to demonstrate the proposed scheme can not only reuse the learned knowledge to achieve the better control performance with the faster tracking convergence rate and the smaller tracking error but also greatly alleviate the computational burden because of reducing the number and complexity of NN input variables.

  1. Nanoscale Manipulators: Review of Conceptual Designs Through Recent Patents.

    Science.gov (United States)

    Mekid, Samir; Bashmal, Salem; Ouakad, Hassen M

    2016-01-01

    Nanomanipulation techniques have gone through several phases to be used in scientific explorations not only to reveal more characteristics of nano, micro and mesoscopic phenomena but also to build functional nano-devices useful for specific applications. The nano-manipulator becomes a key instrument for technology bridging between sub-nano and mesoscale. The recent patents have exhibited integration of various functions in the nano-devices requiring sub-nanometer precision and highly stable manipulator with substantial pulling/pushing forces. This work reviews patents and works on conceptual designs of existing nanomanipulators with specific features. This includes design analysis leading to ultra-precision motion and stability with discussion of enabling technology. A novel integrated and numerically controlled instrument for nanomanipulation, visualization and inspection/characterization of materials at sub-nanoscale will be presented with a feature to keep the same datum for all operation and hence improve accuracy of samples. This paper has undertaken a review search in a structured examination of bibliographic databases for published and issued patents using a focused review keyword of nano-manipulation. The quality of selected patents was appraised using standard tools. The characteristics of screened patents were described, and a deductive qualitative content analysis methodology was applied to understand the modeling and testing of nanomachining process, the exact construction of nanostructure arrays and the inspection of devices with complex features. The paper encompassed forty patents. Fourteen patents exhibited the manipulation at the micro scale (MEMS manipulations), others outlined systems with sub-micron resolution and workspace range in mesoscale. Standard scale manipulation were described in 13 patents assuming only systems comprising positioning stages, arms and end-effectors where positioners are a few centimeters in size with workspace higher

  2. Optical Properties of Nanoscale Bismuth Selenide and Its Heterocrystals

    Science.gov (United States)

    Vargas, Anthony

    Over the past 12 years since the groundbreaking work on graphene, the field of 2D layered materials has grown by leaps and bounds as more materials are theoretically predicted and experimentically verified. These materials and their unique electronic, optical, and mechanical properties have inspired the scientific community to explore and investigate novel, fundamental physical phenomena as well create and refine technological devices which leverage the host of unique benefits which these materials possess. In the past few years, this burgeoning field has heavily moved towards combining layers of various materials into novel heterostructures. These heterostructures are an exciting area of research because of the plethora of exciting possibilities and results which arise due to the large number of heterostructure combinations and configurations. Particularly, the research into the optical properties of these layered materials and their heterostructures under confinement provides another exciting avenue for developing optoelectric devices. In this dissertation, I present work on the synthesis of Bi2Se 3 nanostructures via chemical vapor deposition (CVD) and the study of the optical properties of these nanostructures and their heterostructures with MoS2. The bulk of the current published work on Bi2Se 3 has focused on the exotic topological properties of its surface states, both interesting fundamental physics purposes as well as for studying avenues for spintronics. In contrast, the work presented here focuses on studying the optical properties of Bi2Se3 nanostructures and how these properties evolve when subjected to confinement. Specifically, the absorbance of singlecrystal Bi2Se3 with sizes tailored down to a few nanometers in diameter and a few quintuple layers (QLs) in thickness. We find a dramatically large bandgap, Eg ≥ 2.5 eV, in the smallest particles which is much higher than that seen in 1QL measurements taken with ARPES. Additionally, utilizing

  3. Writing to and reading from a nano-scale crossbar memory based on memristors.

    Science.gov (United States)

    Vontobel, Pascal O; Robinett, Warren; Kuekes, Philip J; Stewart, Duncan R; Straznicky, Joseph; Stanley Williams, R

    2009-10-21

    We present a design study for a nano-scale crossbar memory system that uses memristors with symmetrical but highly nonlinear current-voltage characteristics as memory elements. The memory is non-volatile since the memristors retain their state when un-powered. In order to address the nano-wires that make up this nano-scale crossbar, we use two coded demultiplexers implemented using mixed-scale crossbars (in which CMOS-wires cross nano-wires and in which the crosspoint junctions have one-time configurable memristors). This memory system does not utilize the kind of devices (diodes or transistors) that are normally used to isolate the memory cell being written to and read from in conventional memories. Instead, special techniques are introduced to perform the writing and the reading operation reliably by taking advantage of the nonlinearity of the type of memristors used. After discussing both writing and reading strategies for our memory system in general, we focus on a 64 x 64 memory array and present simulation results that show the feasibility of these writing and reading procedures. Besides simulating the case where all device parameters assume exactly their nominal value, we also simulate the much more realistic case where the device parameters stray around their nominal value: we observe a degradation in margins, but writing and reading is still feasible. These simulation results are based on a device model for memristors derived from measurements of fabricated devices in nano-scale crossbars using Pt and Ti nano-wires and using oxygen-depleted TiO(2) as the switching material.

  4. 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.

  5. Imaging interfaces defined by abruptly varying internal magnetic fields by means of scanned nanoscale spin wave modes

    Science.gov (United States)

    Du, Chunhui; Lee, Inhee; Adur, Rohan; Obukhov, Yuri; Hamann, Christine; Buchner, Bernd; McCord, Jeffrey; Pelekhov, Denis V.; Hammel, P. Chris

    2015-12-01

    Nanoscale devices fabricated out of magnetic heterostructures are central to the emerging field of spintronics, so understanding of magnetization dynamics at interfaces between dissimilar materials is essential. Here we report local imaging of magnetization dynamics at the interface formed by a sharp discontinuity in the magnetic properties of a ferromagnetic thin film using localized mode ferromagnetic resonance force microscopy (FMRFM). The behavior of the localized modes near the interface evolves with increasing magnitude of the FMRFM probe field due to its competition with the steplike internal demagnetizing field. We use micromagnetic modeling to visualize the evolution of the localized mode as the magnetic probe is scanned across the interface. Our results demonstrate the ability to image sharp changes in internal magnetic properties in nanoscale devices and provide insights into the mechanisms underlying the generation and manipulation of localized modes near the interface, thus providing a new tool for microscopic studies of spin transport across magnetic interfaces and spin dynamics in their vicinity.

  6. Controlling mechanical properties of bio-inspired hydrogels by modulating nano-scale, inter-polymeric junctions

    Directory of Open Access Journals (Sweden)

    Seonki Hong

    2014-06-01

    Full Text Available Quinone tanning is a well-characterized biochemical process found in invertebrates, which produce diverse materials from extremely hard tissues to soft water-resistant adhesives. Herein, we report new types of catecholamine PEG derivatives, PEG-NH-catechols that can utilize an expanded spectrum of catecholamine chemistry. The PEGs enable simultaneous participation of amine and catechol in quinone tanning crosslinking. The intermolecular reaction between PEG-NH-catechols forms a dramatic nano-scale junction resulting in enhancement of gelation kinetics and mechanical properties of PEG hydrogels compared to results obtained by using PEGs in the absence of amine groups. Therefore, the study provides new insight into designing new crosslinking chemistry for controlling nano-scale chemical reactions that can broaden unique properties of bulk hydrogels.

  7. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  8. 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.

  9. 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.

  10. Anatomy of a Nanoscale Conduction Channel Reveals the Mechanism of a High-Performance Memristor

    Science.gov (United States)

    Miao, Feng; Strachan, John Paul; Yang, J. Joshua; Yi, Wei; Goldfarb, Ilan; Zhang, M.-X.; Torrezan, Antonio C.; Eschbach, Peter; Kelley, Ronald D.; Medeiros-Ribeiro, Gilberto; Williams, R. Stanley

    2012-02-01

    Two major challenges for resistance memory devices (memristors) based on conductivity changes in oxide materials are better performance and understanding of the microscopic picture of the switching. After researchers' relentless pursuit for years, tantalum oxide-based memristors have rapidly risen to be the top candidate, showing fast speed, high endurance and excellent scalability. While the microscopic picture of these devices remains obscure, by employing a precise method for locating and directly visualizing the conduction channel, here we observed a nanoscale channel consisting of an amorphous Ta(O) solid solution surrounded by crystalline Ta2O5. Structural and chemical analyses of the channel combined with temperature dependent transport measurements revealed a unique resistance switching mechanism: the modulation of the channel elemental composition, and thus the conductivity, by the cooperative influence of drift, diffusion and thermophoresis, which seem to enable the high switching performance observed. (Miao*, Strachan*, Yang* et al., Advanced Materials. DOI: 10.1002/adma201103379 (2011))

  11. Stencil nano lithography based on a nanoscale polymer shadow mask: towards organic nanoelectronics.

    Science.gov (United States)

    Yun, Hoyeol; Kim, Sangwook; Kim, Hakseong; Lee, Junghyun; McAllister, Kirstie; Kim, Junhyung; Pyo, Sengmoon; Sung Kim, Jun; Campbell, Eleanor E B; Hyoung Lee, Wi; Wook Lee, Sang

    2015-05-11

    A stencil lithography technique has been developed to fabricate organic-material-based electronic devices with sub-micron resolution. Suspended polymethylmethacrylate (PMMA) membranes were used as shadow masks for defining organic channels and top electrodes. Arrays of pentacene field effect transistors (FETs) with various channel lengths from 50 μm down to 500 nm were successfully produced from the same batch using this technique. Electrical transport measurements showed that the electrical contacts of all devices were stable and the normalized contact resistances were much lower than previously studied organic FETs. Scaling effects, originating from the bulk space charge current, were investigated by analyzing the channel-length-dependent mobility and hysteresis behaviors. This novel lithography method provides a reliable means for studying the fundamental transport properties of organic materials at the nanoscale as well as enabling potential applications requiring the fabrication of integrated organic nanoelectronic devices.

  12. ISOLDE takes big science to nanoscale

    CERN Multimedia

    Roberto Cantoni

    2010-01-01

    New materials that could replace the semiconductors currently used in Blu-ray and other electronic devices, cost-efficient silicon for a new generation of solar panels, innovative investigation techniques for archaeology, biophysics and biochemistry…behind all this are the studies using nuclear hyperfine interactions. Of paramount importance in such studies is the availability of a large variety of radioactive ion beams: at CERN, these are produced by the ISOLDE facility.   Students from the University of Leuven and ITN Lisbon working at ISOLDE on a technique used to locate impurities in materials. Nuclear hyperfine interactions and their wide range of applications were the focus of the third Joint International Conference on Hyperfine Interactions and International Symposium on Nuclear Quadrupole Interactions, held at CERN from 12 to 17 September. The conference featured theoretical talks but also studies on magnetic materials, semiconductors, thin films, nano-structures and quantum...

  13. Nanomaterial Case Studies: Nanoscale Titanium Dioxide (External Review Draft)

    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 asses...

  14. Nanoscale experimental study of the morphology of a microcrack in ...

    Indian Academy of Sciences (India)

    A microcrack in a silicon single crystal was experimentally investigated using highresolution transmission electron microscopy (HRTEM). In particular, the numerical Moiré (NM) method was used to visualize the deformations and defects. The lattice structure of the microcrack was carefully observed at the nanoscale. HRTEM ...

  15. Computer simulation of quantum phenomena in nano-scale devices

    NARCIS (Netherlands)

    Raedt, Hans De

    1996-01-01

    This paper reviews the general concepts for building algorithms to solve the time-dependent Schrödinger equation and to discuss ways of turning these concepts into unconditionally stable, accurate and efficient simulation algorithms. Applications to focussed electron emission from nano-scale

  16. Capacitance tuning of nanoscale split-ring resonators

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Mortensen, Asger; Kristensen, Anders

    2009-01-01

    We investigate the capacitance tuning of nanoscale split-ring resonators. Based on a simple inductor-capacitor circuit model, we derive an expression, where the inductance is proportional to the area while the capacitance reflects the aspect ratio of the slit. The resonance frequency may thus...

  17. Capacitance tuning of nanoscale split-ring resonators

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Xiao, Sanshui; Mortensen, Niels Asger

    2010-01-01

    In this paper, we investigate the capacitance tuning of nanoscale split-ring resonators. Based on a simple LC circuit model (LC-model), we derive an expression where the inductance is proportional to the area while the capacitance reflects the aspect ratio of the slit. The resonance frequency may...

  18. Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

    NARCIS (Netherlands)

    Zecevic, Jovana|info:eu-repo/dai/nl/341386715; Vanbutsele, Gina; de Jong, Krijn P.|info:eu-repo/dai/nl/06885580X; Martens, Johan A.

    2015-01-01

    The ability to control nanoscale features precisely is increasingly being exploited to develop and improve monofunctional catalysts(1-4). Striking effects might also be expected in the case of bifunctional catalysts, which are important in the hydrocracking of fossil and renewable hydrocarbon

  19. Topology optimization for nano-scale heat transfer

    DEFF Research Database (Denmark)

    Evgrafov, Anton; Maute, Kurt; Yang, Ronggui

    2009-01-01

    We consider the problem of optimal design of nano-scale heat conducting systems using topology optimization techniques. At such small scales the empirical Fourier's law of heat conduction no longer captures the underlying physical phenomena because the mean-free path of the heat carriers, phonons...

  20. Cationic nanoparticles induce nanoscale disruption in living cell plasma membranes.

    Science.gov (United States)

    Chen, Jiumei; Hessler, Jessica A; Putchakayala, Krishna; Panama, Brian K; Khan, Damian P; Hong, Seungpyo; Mullen, Douglas G; Dimaggio, Stassi C; Som, Abhigyan; Tew, Gregory N; Lopatin, Anatoli N; Baker, James R; Holl, Mark M Banaszak; Orr, Bradford G

    2009-08-13

    It has long been recognized that cationic nanoparticles induce cell membrane permeability. Recently, it has been found that cationic nanoparticles induce the formation and/or growth of nanoscale holes in supported lipid bilayers. In this paper, we show that noncytotoxic concentrations of cationic nanoparticles induce 30-2000 pA currents in 293A (human embryonic kidney) and KB (human epidermoid carcinoma) cells, consistent with a nanoscale defect such as a single hole or group of holes in the cell membrane ranging from 1 to 350 nm(2) in total area. Other forms of nanoscale defects, including the nanoparticle porating agents adsorbing onto or intercalating into the lipid bilayer, are also consistent; although the size of the defect must increase to account for any reduction in ion conduction, as compared to a water channel. An individual defect forming event takes 1-100 ms, while membrane resealing may occur over tens of seconds. Patch-clamp data provide direct evidence for the formation of nanoscale defects in living cell membranes. The cationic polymer data are compared and contrasted with patch-clamp data obtained for an amphiphilic phenylene ethynylene antimicrobial oligomer (AMO-3), a small molecule that is proposed to make well-defined 3.4 nm holes in lipid bilayers. Here, we observe data that are consistent with AMO-3 making approximately 3 nm holes in living cell membranes.

  1. Size dependence of nanoscale wear of silicon carbide

    Science.gov (United States)

    Chaiyapat Tangpatjaroen; David Grierson; Steve Shannon; Joseph E. Jakes; Izabela Szlufarska

    2017-01-01

    Nanoscale, single-asperity wear of single-crystal silicon carbide (sc- SiC) and nanocrystalline silicon carbide (nc-SiC) is investigated using single-crystal diamond nanoindenter tips and nanocrystalline diamond atomic force microscopy (AFM) tips under dry conditions, and the wear behavior is compared to that of single-crystal silicon with both thin and thick native...

  2. 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

  3. Method for preparing microstructure arrays on the surface of thin film material

    KAUST Repository

    Wang, Peng

    2017-02-09

    Methods are provided for growing a thin film of a nanoscale material. Thin films of nanoscale materials are also provided. The films can be grown with microscale patterning. The method can include vacuum filtration of a solution containing the nanostructured material through a porous substrate. The porous substrate can have a pore size that is comparable to the size of the nanoscale material. By patterning the pores on the surface of the substrate, a film can be grown having the pattern on a surface of the thin film, including on the top surface opposite the substrate. The nanoscale material can be graphene, graphene oxide, reduced graphene oxide, molybdenum disulfide, hexagonal boron nitride, tungsten diselenide, molybdenum trioxide, or clays such as montmorillonite or lapnotie. The porous substrate can be a porous organic or inorganic membrane, a silicon stencil membrane, or similar membrane having pore sizes on the order of microns.

  4. Contact engineering for nano-scale CMOS

    KAUST Repository

    Hussain, Muhammad Mustafa

    2012-09-10

    High performance computation with longer battery lifetime is an essential component in our today\\'s digital electronics oriented life. To achieve these goals, field effect transistors based complementary metal oxide semiconductor play the key role. One of the critical requirements of transistor structure and fabrication is efficient contact engineering. To catch up with high performance information processing, transistors are going through continuous scaling process. However, it also imposes new challenges to integrate good contact materials in a small area. This can be counterproductive as smaller area results in higher contact resistance thus reduced performance for the transistor itself. At the same time, discovery of new one or two-dimensional materials like nanowire, nanotube, or atomic crystal structure materials, introduces new set of challenges and opportunities. In this paper, we are reviewing them in a synchronized fashion: fundamentals of contact engineering, evolution into non-planar field effect transistors, opportunities and challenges with one and two-dimensional materials and a new opportunity of contact engineering from device architecture perspective. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Reduced wear of enamel with novel fine and nano-scale leucite glass-ceramics.

    Science.gov (United States)

    Theocharopoulos, Antonios; Chen, Xiaohui; Hill, Robert; Cattell, Michael J

    2013-06-01

    Leucite glass-ceramics used to produce all-ceramic restorations can suffer from brittle fracture and wear the opposing teeth. High strength and fine crystal sized leucite glass-ceramics have recently been reported. The objective of this study is to investigate whether fine and nano-scale leucite glass-ceramics with minimal matrix microcracking are associated with a reduction in in vitro tooth wear. Human molar cusps (n=12) were wear tested using a Bionix-858 testing machine (300,000 simulated masticatory cycles) against experimental fine crystal sized (FS), nano-scale crystal sized (NS) leucite glass-ceramics and a commercial leucite glass-ceramic (Ceramco-3, Dentsply, USA). Wear was imaged using Secondary Electron Imaging (SEI) and quantified using white-light profilometry. Both experimental groups were found to produce significantly (pceramic) loss than the FS group. Increased waviness and damage was observed on the wear surfaces of the Ceramco-3 glass-ceramic disc/tooth group in comparison to the experimental groups. This was also indicated by higher surface roughness values for the Ceramco-3 glass-ceramic disc/tooth group. Fine and nano-sized leucite glass-ceramics produced a reduction in in vitro tooth wear. The high strength low wear materials of this study may help address the many problems associated with tooth enamel wear and restoration failure. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-04-12

    Hybrid organic-inorganic perovskites based on methylammonium lead (MAPbI 3 ) are an emerging material with great potential for high-performance and low-cost photovoltaics. However, for perovskites to become a competitive and reliable solar cell technology their instability and spatial variation must be understood and controlled. While the macroscopic characterization of the devices as a function of time is very informative, a nanoscale identification of their real-time local optoelectronic response is still missing. Here, we implement a four-dimensional imaging method through illuminated heterodyne Kelvin probe force microscopy to spatially (300 mV under 1-sun illumination. Surprisingly, regions of voltage that relax in seconds and after several minutes consistently coexist. Time-dependent changes of the local V oc are likely due to intragrain ion migration and are reversible at low injection level. These results show for the first time the real-time transient behavior of the V oc in perovskite solar cells at the nanoscale. Understanding and controlling the light-induced electrical changes that affect device performance are critical to the further development of stable perovskite-based solar technologies.

  7. Quantum many-body theory for electron spin decoherence in nanoscale nuclear spin baths.

    Science.gov (United States)

    Yang, Wen; Ma, Wen-Long; Liu, Ren-Bao

    2017-01-01

    Decoherence of electron spins in nanoscale systems is important to quantum technologies such as quantum information processing and magnetometry. It is also an ideal model problem for studying the crossover between quantum and classical phenomena. At low temperatures or in light-element materials where the spin-orbit coupling is weak, the phonon scattering in nanostructures is less important and the fluctuations of nuclear spins become the dominant decoherence mechanism for electron spins. Since the 1950s, semi-classical noise theories have been developed for understanding electron spin decoherence. In spin-based solid-state quantum technologies, the relevant systems are in the nanometer scale and nuclear spin baths are quantum objects which require a quantum description. Recently, quantum pictures have been established to understand the decoherence and quantum many-body theories have been developed to quantitatively describe this phenomenon. Anomalous quantum effects have been predicted and some have been experimentally confirmed. A systematically truncated cluster-correlation expansion theory has been developed to account for the many-body correlations in nanoscale nuclear spin baths that are built up during electron spin decoherence. The theory has successfully predicted and explained a number of experimental results in a wide range of physical systems. In this review, we will cover this recent progress. The limitations of the present quantum many-body theories and possible directions for future development will also be discussed.

  8. Nanoscale modifications in the early heating stages of bone are heterogeneous at the microstructural scale.

    Science.gov (United States)

    Gourrier, Aurélien; Chadefaux, Céline; Lemaitre, Estelle; Bellot-Gurlet, Ludovic; Reynolds, Michael; Burghammer, Manfred; Plazanet, Marie; Boivin, Georges; Farlay, Delphine; Bunk, Oliver; Reiche, Ina

    2017-01-01

    Nanoscale studies of bone provide key indicators to evidence subtle structural changes that may occur in the biomedical, forensic and archaeological contexts. One specific problem encountered in all those disciplines, for which the identification of nanostructural cues could prove useful, is to properly monitor the effect of heating on bone tissue. In particular, the mechanisms at work at the onset of heating are still relatively unclear. Using a multiscale approach combining Raman microspectroscopy, transmission electron microscopy (TEM), synchrotron quantitative scanning small-angle X-ray scattering imaging (qsSAXSI) and polarized light (PL) microscopy, we investigate the ultrastructure of cortical bovine bone heated at temperatures stems from the tissue histology, i.e. from the high degree of heterogeneity of the microstructure induced by the complex cellular processes involved in bone tissue formation. From this study, we conclude that the analysis of bone samples based on the structure and organization of the mineral nanocrystals requires performing measurements at the histological level, which is an advantageous feature of qsSAXSI. This is a critical aspect that extends to a much broader range of questions relating to nanoscale investigations of bone, which could also be extended to other classes of nanostructured heterogeneous materials.

  9. Superstrength of nanograined steel with nanoscale intermetallic precipitates transformed from shock-compressed martensitic steel.

    Science.gov (United States)

    Yu, Hailiang; Yan, Ming; Lu, Cheng; Tieu, Anh Kiet; Li, Huijun; Zhu, Qiang; Godbole, Ajit; Li, Jintao; Su, Lihong; Kong, Charlie

    2016-11-28

    An increasing number of industrial applications need superstrength steels. It is known that refined grains and nanoscale precipitates can increase strength. The hardest martensitic steel reported to date is C0.8 steel, whose nanohardness can reach 11.9 GPa through incremental interstitial solid solution strengthening. Here we report a nanograined (NG) steel dispersed with nanoscale precipitates which has an extraordinarily high hardness of 19.1 GPa. The NG steel (shock-compressed Armox 500T steel) was obtained under these conditions: high strain rate of 1.2 μs(-1), high temperature rise rate of 600 Kμs(-1) and high pressure of 17 GPa. The mean grain size achieved was 39 nm and reinforcing precipitates were indexed in the NG steel. The strength of the NG steel is expected to be ~3950 MPa. The discovery of the NG steel offers a general pathway for designing new advanced steel materials with exceptional hardness and excellent strength.

  10. The Effect of Thickness and Chemical Reduction of Graphene Oxide on Nanoscale Friction.

    Science.gov (United States)

    Kwon, Sangku; Lee, Kyung Eun; Lee, Hyunsoo; Koh, Sang Joon; Ko, Jae-Hyeon; Kim, Yong-Hyun; Kim, Sang Ouk; Park, Jeong Young

    2018-01-18

    The tribological properties of two-dimensional (2D) atomic layers are quite different from three-dimensional continuum materials because of the unique mechanical responses of 2D layers. It is known that friction on graphene shows a remarkable decreasing behavior as the number of layers increases, which is caused by the puckering effect. On other graphene derivatives, such as graphene oxide (GO) or reduced graphene oxide (rGO), the thickness dependence of friction is important because of the possibilities for technical applications. In this report, we demonstrate unexpected layer-dependent friction behavior on GO and rGO layers. Friction force microscopy measurements show that nanoscale friction on GO does not depend on the number of layers; however, after reduction, friction on rGO shows an inverse thickness dependence compared with pristine graphene. We show that the friction on rGO is higher than that on SiO2 at low load, and that an interesting crossover behavior at higher load occurs because of the lower friction coefficient and higher adhesion of the rGO. We provide a relevant interpretation that explains the effect of thickness and chemical reduction on nanoscale friction.

  11. Study of the Photo- and Thermoactivation Mechanisms in Nanoscale SOI Modulator

    Directory of Open Access Journals (Sweden)

    Yaakov Mandelbaum

    2017-01-01

    Full Text Available A new nanoscale silicon-based modulator has been investigated at different temperatures. In addition to these two advantages, nanoscale dimensions (versus MEMS temperature sensors and integrated silicon-based material (versus polymers, the third novelty of such optoelectronic device is that it can be activated as a Silicon-On-Insulator Photoactivated Modulator (SOIPAM or as a Silicon-On-Insulator Thermoactivated Modulator (SOITAM. In this work, static and time dependent temperature effects on the current have been investigated. The aim of the time dependent temperature simulation was to set a temporal pulse and to check, for given dimensions, how much time would it take for the temperature profile and for the change in the electrons’ concentration to come back to the steady state. Assuring that the thermal response is fast enough, the device can be operated as a modulator via thermal stimulation or, on the other hand, can be used as thermal sensor/imager. We present here the design, simulation, and model of the second generation which seems capable of speeding up the processing capabilities. This novel device can serve as a building block towards the development of optical/thermal data processing while breaking through the way to all optic processors based on silicon chips that are fabricated via typical microelectronics fabrication process.

  12. Nanoscale imaging of Li and B in nuclear waste glass, a comparison of ToF-SIMS, NanoSIMS, and APT: Nanoscale imaging of Li and B in nuclear waste glass

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaoying [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Beijing Centre for Mass Spectrometry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 China; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Liu, Jia [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Zhou, Yufan [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; School of Physics, State Key Laboratory of Crystal Materials & Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Jinan 250100 China; Neeway, James J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Schreiber, Daniel K. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Crum, Jarrod V. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Ryan, Joseph V. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Wang, Xue-Lin [School of Physics, State Key Laboratory of Crystal Materials & Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Jinan 250100 China; Wang, Fuyi [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Beijing Centre for Mass Spectrometry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 China; Zhu, Zihua [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA

    2016-06-02

    It has been very difficult to use popular elemental imaging techniques to image Li and B distribution in glass samples with nanoscale resolution. In this study, atom probe tomography (APT), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and nanoscale secondary ion mass spectrometry (NanoSIMS) were used to image the distribution of Li and B in two representative glass samples. APT can provide three-dimensional Li and B imaging with very high spatial resolution (≤ 2 nm). In addition, absolute quantification of Li and B is possible, though room remains to improve accuracy. However, the major drawbacks of APT include limited field of view (normally ≤ 100 × 100 × 500 nm3) and poor sample compatibility. As a comparison, ToF-SIMS and NanoSIMS are sample-friendly with flexible field of view (up to 500 × 500 μm2 and image stitching is feasible); however, lateral resolution is limited to only about 100 nm. Therefore, SIMS and APT can be regarded as complementary techniques for nanoscale imaging Li and B in glass and other novel materials.

  13. Nanoscale Molecules Under Thermodynamic Control:" Digestive Ripening" or " Nanomachining"

    Energy Technology Data Exchange (ETDEWEB)

    Klabunde, Kenneth J. [Kansas State Univ., Manhattan, KS (United States)

    2015-06-04

    Overall Research Goals and Specific Objectives: Nanoscale materials are becoming ubiquitous in science and engineering, and are found widely in nature. However, their formation processes and uniquely high chemical reactivities are not understood well, indeed are often mysterious. Over recent years, a number of research teams have described nanoparticle synthesis, and aging, thermal treatment, or etching times have been mentioned. We have used the terms “digestive ripening” and “nanomachining” and have suggested that thermodynamics plays an important part in the size adjustment to monodisperse arrays being formed. Since there is scant theoretical understanding of digestive ripening, the overall goal in our research is to learn what experimental parameters (ligand used, temperature, solvent, time) are most important, how to control nanoparticle size and shape after initial crude nanoparticles have been synthesized, and gain better understanding of the chemical mechanism details. Specific objectives for the past twentynine months since the grant began have been to (1) Secure and train personnel;as of 2011, a postdoc Deepa Jose, female from the Indian Institute of Science in Bangalore, India; Yijun Sun, a second year graduate student, female from China; and Jessica Changstrom, female from the USA, GK12 fellow (program for enhancing teaching ability) are actively carrying out research. (2) Find out what happens to sulfur bound hydrogen of thiol when it interacts with gold nanoparticles. Our findings are discussed in detail later. (3) Determine the effect of particle size, shape, and temperature on dodecyl thiol assited digestive ripening of gold nanoparticles. See our discussions later. (4) To understand in detail the ligand interaction in molecular clusters and nanoparticles (5) Determine the effect of chain length of amines on Au nanoparticle size under digestive ripening conditions (carbon chain length varied from 4-18). (6) Determine the catalytic activity

  14. Etching patterns on the micro‐ and nanoscale

    DEFF Research Database (Denmark)

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

    2014-01-01

    and polymer injection molding. High precision patterns of, for instance microfluidic devices, are etched intosilicon which is then electroplated with nickel that will serve as a stamp in the polymer injection molding tool where thousands of devices may be replicated. In addition to silicon and its derived......, materials and depths. With the dry etchtools available in the cleanroom at DTU‐Danchip, the etching of a great variety of materials may be tunedvery precisely from a purely chemical and isotropic etch to a purely physical and anisotropic etch.The dry etching of silicon is the most flexible and well......‐established process that enables the users of our lab to realize devices on any scale in the sub 100 nm to the sub 1 mm range. The silicon compound refractive lenses (see left figure) for focusing hard X‐rays from a synchrotron source are examples of etch processes with extreme specifications. In order to focus the X...

  15. 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...... of materials in a given plastic part. Also, the reduction of process steps and materials leads to a reduction of the fabrication costs. In the thesis only surfaces, which may be fabricated using replication based methods, such as injection molding, are considered. Nanostructures with sizes comparable......-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...

  16. Nanoscale Studies of Pyroelectric and Thermoelectric Phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Gruverman, Alexei [Univ. of Nebraska, Lincoln, NE (United States); Ducharme, Stephen [Univ. of Nebraska, Lincoln, NE (United States)

    2014-07-31

    This research project is focused on (1) development of novel scanning probe microscopy techniques for investigation of the thermally and electrically induced changes in the physical properties of organic polymer ferroelectrics; (2) fabrication of ferroelectric nanostructures and investigation of their functional behavior; (3) fabrication and testing of the organic photovoltaic devices with enhanced energy conversion efficiency. Research activities throughout this project resulted in novel effects and exciting physics reported in 10 papers published in high-profile journals, including Nature Materials, Nano Letters, Advanced Materials, Energy and Environmental Science and Applied Physics Letters. These findings have been presented at a number of domestic and international conferences such as MRS Spring and Fall meetings, International Symposium on Integrated Functionalities, International Symposium on Applications of Ferroelectrics (in total 9 presentations). Below we summarize the most important findings of this project.

  17. Nanoscale Advances in Catalysis and Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yimin; Somorjai, Gabor A.

    2010-05-12

    In this perspective, we present an overview of nanoscience applications in catalysis, energy conversion, and energy conservation technologies. We discuss how novel physical and chemical properties of nanomaterials can be applied and engineered to meet the advanced material requirements in the new generation of chemical and energy conversion devices. We highlight some of the latest advances in these nanotechnologies and provide an outlook at the major challenges for further developments.

  18. Art on the Nanoscale and Beyond.

    Science.gov (United States)

    Yetisen, Ali K; Coskun, Ahmet F; England, Grant; Cho, Sangyeon; Butt, Haider; Hurwitz, Jonty; Kolle, Mathias; Khademhosseini, Ali; Hart, A John; Folch, Albert; Yun, Seok Hyun

    2016-03-02

    Methods of forming and patterning materials at the nano- and microscales are finding increased use as a medium of artistic expression, and as a vehicle for communicating scientific advances to a broader audience. While sharing many attributes of other art forms, miniaturized art enables the direct engagement of sensory aspects such as sight and touch for materials and structures that are otherwise invisible to the eye. The historical uses of nano-/microscale materials and imaging techniques in arts and sciences are presented. The motivations to create artwork at small scales are discussed, and representations in scientific literature and exhibitions are explored. Examples are presented using semiconductors, microfluidics, and nanomaterials as the artistic media; these utilized techniques including micromachining, focused ion beam milling, two-photon polymerization, and bottom-up nanostructure growth. Finally, the technological factors that limit the implementation of artwork at miniature scales are identified, and potential future directions are discussed. As research marches toward even smaller length scales, innovative and engaging visualizations and artistic endeavors will have growing implications on education, communication, policy making, media activism, and public perception of science and technology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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

  20. Teaching Tools for Pedagogy at the Nanoscale: Towards the Understanding of Concepts Through Experience and Experimentation

    Science.gov (United States)

    Muniz, Marc Nicholas

    The field of nanochemistry is at the forefront of the physical sciences, and is increasingly finding diverse applications. As such, there is a need to allow this frontier to be explored thoroughly in undergraduate chemistry curricula. The development of new instructional materials is necessary, as the existing literature in undergraduate nanochemistry education does not provide instructors with adequate resources to help students make connections between core scientific concepts and those pertinent to the nanoscale. As such, we aim to treat nanoscale phenomena not as a niche subject but as an educationally rich portion of chemistry at the interface of discrete and bulk structures. To accomplish this, we have developed and tested instructional materials that are designed to fit directly into the chemistry curriculum and provide instructors with the flexibility to incorporate them in their courses. These teaching tools/modules have been designed using a theoretical framework for analogy and similarity coupled with a bridging framework in order to reinforce students' physical and chemical concepts and facilitate their recognition of such in the context of nanochemistry. Our approach is to construct concepts related to nanochemistry by tethering them directly, through the use of analogy and similarity, to material commonly covered within the courses, rather than present them in an unrelated fashion or completely outside the students' current frame of reference. Assessment of these tools has been carried out through a qualitative analysis incorporating a discourse analytical framework applied to individual student interviews and small group discussions. A coding scheme was devised and utilized for consistent characterization of students' responses and discussions. Results are discussed critically and pedagogical implications for each activity and the project as a whole are provided.

  1. Trends in nanoscale mechanics mechanics of carbon nanotubes, graphene, nanocomposites and molecular dynamics

    CERN Document Server

    2014-01-01

    This book contains a collection of the state-of-the-art reviews written by the leading researchers in the areas of nanoscale mechanics, molecular dynamics, nanoscale modeling of nanocomposites and mechanics of carbon nanotubes. No other book has reviews of the recent discoveries such as a nanoscale analog of the Pauli’s principle, i.e., effect of the spatial exclusion of electrons or the SEE effect, a new Registry Matrix Analysis for the nanoscale interfacial sliding and new data on the effective viscosity of interfacial electrons in nanoscale stiction at the interfaces. This volume is also an exceptional resource on the well tested nanoscale modeling of carbon nanotubes and nanocomposites, new nanoscale effects, unique evaluations of the effective thickness of carbon nanotubes under different loads, new data on which size of carbon nanotubes is safer and many other topics. Extensive bibliography concerning all these topics is included along with the lucid short reviews. Numerous illustrations are provided...

  2. Adaptive fuzzy dynamic surface control of nonlinear systems with input saturation and time-varying output constraints

    Science.gov (United States)

    Edalati, L.; Khaki Sedigh, A.; Aliyari Shooredeli, M.; Moarefianpour, A.

    2018-02-01

    This paper deals with the design of adaptive fuzzy dynamic surface control for uncertain strict-feedback nonlinear systems with asymmetric time-varying output constraints in the presence of input saturation. To approximate the unknown nonlinear functions and overcome the problem of explosion of complexity, a Fuzzy logic system is combined with the dynamic surface control in the backstepping design technique. To ensure the output constraints satisfaction, an asymmetric time-varying Barrier Lyapunov Function (BLF) is used. Moreover, by applying the minimal learning parameter technique, the number of the online parameters update for each subsystem is reduced to 2. Hence, the semi-globally uniformly ultimately boundedness (SGUUB) of all the closed-loop signals with appropriate tracking error convergence is guaranteed. The effectiveness of the proposed control is demonstrated by two simulation examples.

  3. Nonlinear Dynamic Surface Control of Chaos in Permanent Magnet Synchronous Motor Based on the Minimum Weights of RBF Neural Network

    Directory of Open Access Journals (Sweden)

    Shaohua Luo

    2014-01-01

    Full Text Available This paper is concerned with the problem of the nonlinear dynamic surface control (DSC of chaos based on the minimum weights of RBF neural network for the permanent magnet synchronous motor system (PMSM wherein the unknown parameters, disturbances, and chaos are presented. RBF neural network is used to approximate the nonlinearities and an adaptive law is employed to estimate unknown parameters. Then, a simple and effective controller is designed by introducing dynamic surface control technique on the basis of first-order filters. Asymptotically tracking stability in the sense of uniformly ultimate boundedness is achieved in a short time. Finally, the performance of the proposed controller is testified through simulation results.

  4. History-dependent ion transport through conical nanopipettes and the implications in energy conversion dynamics at nanoscale interfaces.

    Science.gov (United States)

    Li, Yan; Wang, Dengchao; Kvetny, Maksim M; Brown, Warren; Liu, Juan; Wang, Gangli

    2015-01-01

    The dynamics of ion transport at nanostructured substrate-solution interfaces play vital roles in high-density energy conversion, stochastic chemical sensing and biosensing, membrane separation, nanofluidics and fundamental nanoelectrochemistry. Further advancements in these applications require a fundamental understanding of ion transport at nanoscale interfaces. The understanding of the dynamic or transient transport, and the key physical process involved, is limited, which contrasts sharply with widely studied steady-state ion transport features at atomic and nanometer scale interfaces. Here we report striking time-dependent ion transport characteristics at nanoscale interfaces in current-potential ( I - V ) measurements and theoretical analyses. First, a unique non-zero I - V cross-point and pinched I - V curves are established as signatures to characterize the dynamics of ion transport through individual conical nanopipettes. Second, ion transport against a concentration gradient is regulated by applied and surface electrical fields. The concept of ion pumping or separation is demonstrated via the selective ion transport against concentration gradients through individual nanopipettes. Third, this dynamic ion transport process under a predefined salinity gradient is discussed in the context of nanoscale energy conversion in supercapacitor type charging-discharging, as well as chemical and electrical energy conversion. The analysis of the emerging current-potential features establishes the urgently needed physical foundation for energy conversion employing ordered nanostructures. The elucidated mechanism and established methodology can be generalized into broadly-defined nanoporous materials and devices for improved energy, separation and sensing applications.

  5. Manipulation of the elastic modulus of polymers at the nanoscale: influence of UV-ozone cross-linking and plasticizer.

    Science.gov (United States)

    Torres, Jessica M; Stafford, Christopher M; Vogt, Bryan D

    2010-09-28

    The mechanical stability of polymeric nanostructures is critical to the processing, assembly, and performance of numerous existing and emerging technologies. A key predictor of mechanical stability is the elastic modulus. However, a significant reduction in modulus has been reported for thin films and nanostructures when the thickness or size of the polymer material decreases below a critical length scale. Routes to mitigate or even eliminate this reduction in modulus, and thus enhancing the mechanically stability of polymeric nanostructures, would be extremely valuable. Here, two routes to modulate the mechanical properties of polymers at the nanoscale are described. Exposure to ultraviolet light and ozone (UVO) cross-links the near surface region of high molecular mass PS films, rendering the elastic modulus independent of thickness. However, UVO cannot eliminate the decrease in modulus of low molecular mass PS or PMMA due to limited reaction depth and photodegradation, respectively. Alternatively, the thickness dependence of the elastic modulus of both PS and PMMA can be eliminated by addition of dioctyl phthalate (DOP) at 5% by mass. Furthermore, an increase in modulus is observed for films with thicknesses less than 30 nm with 5% DOP by mass in comparison to neat PS. Although DOP acts as a plasticizer for both PS and PMMA in the bulk, evidence indicates that DOP acts as an antiplasticizer at the nanoscale. By maintaining or even increasing the elastic modulus of polymers at the nanoscale, these methods could lead to improved stability of polymeric nanostructures and devices.

  6. Acute and subchronic oral toxicity studies in rats with nanoscale and pigment grade titanium dioxide particles.

    Science.gov (United States)

    Warheit, D B; Brown, S C; Donner, E M

    2015-10-01

    adverse toxicological effects. Apart from reporting the findings of these three studies, this publication also focuses on additional critical issues associated with particle and nanotoxicology studies. First, describing the detailed methodology requirements and rigor upon which the standardized OECD 408 guideline subchronic oral toxicity studies are conducted. Moreover, an attempt is made to reconcile the complex issue of particle size distribution as it relates to measurements of nanoscale and pigment-grade TiO2 particles. Clearly this has been a confusing issue and often misrepresented in the media and the scientific literature. It is clear that the particle-size distribution for pigment-grade TiO2, contains a small ("tail") component of nanoscale particles (i.e., 21% by particle number and study). However, this robust particle characterization finding should not be confused with mislabeling the test materials as exclusively in the nanoscale range. Moreover, based upon the findings presented herein, there appears to be no significant oral toxicity impact contributed by the nanoscale component of the TiO2 Test Material sample in the 90-day study. Finally, it seems reasonable to conclude that the study findings should be considered for read-across purposes to food-grade TiO2 particles (e.g., E171), as the physicochemical characteristics are quite similar. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Nanoscale Controls on CO2-water-rock Interactions in Saline Reservoirs

    Science.gov (United States)

    Deyoreo, J.; Depaolo, D. J.

    2009-12-01

    It is becoming increasingly widely recognized that geologic sequestration of CO2, when combined with economical means of capture, may be one of the most effective approaches to reducing net CO2 emissions to the atmosphere over the next century. Injection of CO2 into saline geologic formations involves forcing a buoyant, low-viscosity fluid into a more dense, higher viscosity fluid. The difference in wetting properties of the two fluids, their partial miscibility, the fact that CO2 and H2O form an acid, and the heterogeneity of geologic formations combine to make the flow and transport details fascinating but difficult to fully characterize and predict. A major question is whether the flow of CO2 into subsurface formations, the efficiency of pore space filling, and the trapping efficiency can be not only predicted but controlled over the decades of injection that might be associated with the life of a power plant. The major technological gaps to controlling and ultimately sequestering subsurface CO2 can be traced to far-from-equilibrum processes that originate at the molecular and nanoscale, but are expressed as complex emergent behavior at larger scales. Essential knowledge gaps involve the effects of nanoscale confinement on material properties, flow and chemical reactions, the effects of nanoparticles, mineral surface dynamics, and microbiota on mineral dissolution/precipitation and fluid flow, and the dynamics of fluid-fluid and fluid-mineral interfaces. To address these scientific and technical challenges, the Energy Frontier Research Center recently established, involving collaboration between LBNL, ORNL, MIT, UC Berkeley, UC Davis and LLNL, will attempt to bring new approaches to the study of nanoscale phenomena in fluid-rock systems to bear on the problem of CO2 behavior in saline formations. The stated goal is to use molecular, nanoscale, and pore-network scale approaches to control flow, dissolution, and precipitation in deep subsurface rock formations to

  8. Coal surface control for advanced physical fine coal cleaning technologies. Final report, September 19, 1988--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Morsi, B.I.; Chiang, S.H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Cheng, Y.S.; Gray, R.; Streeter, R.; Bi, H.; Campbell, P.; Chiarlli, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.; Venkatadri, R.

    1992-12-31

    This final report presents the research work carried out on the Coal Surface Control for Advanced Physical Fine Coal Cleaning Technologies project, sponsored by the US Department of Energy, Pittsburgh Energy Technology Center (DOE/PETC). The project was to support the engineering development of the selective agglomeration technology in order to reduce the sulfur content of US coals for controlling SO{sub 2} emissions (i.e., acid rain precursors). The overall effort was a part of the DOE/PETCs Acid Rain Control Initiative (ARCI). The overall objective of the project is to develop techniques for coal surface control prior to the advanced physical fine coal cleaning process of selective agglomeration in order to achieve 85% pyrite sulfur rejection at an energy recovery greater than 85% based on run-of-mine coal. The surface control is meant to encompass surface modification during grinding and laboratory beneficiation testing. The project includes the following tasks: Project planning; methods for analysis of samples; development of standard beneficiation test; grinding studies; modification of particle surface; and exploratory R&D and support. The coal samples used in this project include three base coals, Upper Freeport - Indiana County, PA, Pittsburgh NO. 8 - Belmont County, OH, and Illinois No. 6 - Randolph County, IL, and three additional coals, Upper Freeport - Grant County- WV, Kentucky No. 9 Hopkins County, KY, and Wyodak - Campbell County, WY. A total of 149 drums of coal were received.

  9. 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

  10. Nanostructured materials in electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhari, Ali (ed.) [Avicenna Institute of Technology, Cleveland, OH (United States)

    2008-07-01

    Providing the unique and vital link between the worlds of electrochemistry and nanomaterials, this reference and handbook covers advances in electrochemistry through the nanoscale control of electrode structures, as well as advances in nanotechnology through electrochemical synthesis strategies. It demonstrates how electrochemical methods are of great scientific and commercial interest due to their low cost and high efficiency, and includes the synthesis of nanowires, nanoparticles, nanoporous and layered nanomaterials of various compositions, as well as their applications - ranging from superior electrode materials to energy storage, biosensors, and electroanalytical devices. (orig.)

  11. Magnetoresistive nanosensors: controlling magnetism at the nanoscale

    Science.gov (United States)

    Leitao, Diana C.; Silva, Ana V.; Paz, Elvira; Ferreira, Ricardo; Cardoso, Susana; Freitas, Paulo P.

    2016-01-01

    The ability to detect the magnetic fields that surround us has promoted vast technological advances in sensing techniques. Among those, magnetoresistive sensors display an unpaired spatial resolution. Here, we successfully control the linear range of nanometric sensors using an interfacial exchange bias sensing layer coupling. An effective matching of material properties and sensor geometry improves the nanosensor performance, with top sensitivities of 3.7% mT-1. The experimental results are well supported by 3D micromagnetic and magneto-transport simulations.

  12. Nanoindentation Studies Reveal Material Properties of Viruses

    NARCIS (Netherlands)

    Roos, W.H.; Wuite, G.J.L.

    2009-01-01

    Over the last years, a paradigm shift has occurred from approaching viruses solely as disease-bringing agents toward regarding them as functional nanoparticles, and a perfect example of Nature's capability to self-assemble complex, multicomponent materials at the nanoscale. Viruses are now used as

  13. PREFACE: Focus on Materials Nanoarchitectonics Focus on Materials Nanoarchitectonics

    Science.gov (United States)

    Aono, Masakazu

    2011-08-01

    On behalf of the International Center for Materials Nanoarchitectonics (MANA), I wish to express our gratitude for the publication of this special issue of Science and Technology of Advanced Materials (STAM), which highlights our recent research activities at MANA. In this preface, I would like to briefly describe the history and then outline the direction of research at MANA. In 2007, Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) launched the World Premier International Research Center Initiative (WPI Program) to create several frontier research centers in Japan. The aim was to facilitate cutting-edge research by promoting the participation of leading scientists from around the world and by providing an attractive research environment. One of the six centers of the WPI Program is MANA, established at the National Institute for Materials Science (NIMS) in October 2007. The direction of research at MANA is symbolized by the term 'nanoarchitectonics', which is part of the name MANA. What is nanoarchitectonics? In the past quarter century, nanotechnology has made impressive advances and has become an important pillar in the development of new materials. However, to explore its full potential, nanotechnology needs to stay on the path of innovation. In particular, the conventional analytic view of nanotechnology must yield to a certain synthetic approach. This is conducive to creating new functions that can be exhibited by nanoscale structural units through mutual interactions, even though these functions are not present in the isolated units. We coined the term nanoarchitectonics (first used in the name of the 1st International Symposium on Nanoarchitectonics Using Suprainteractions (NASI-1), organized by the author and his colleagues at Tsukuba, Japan, in November 2000) to express this innovation of nanotechnology. More specifically, nanoarchitectonics is a technology system where the aim is arranging nanoscale structural units, which

  14. Nanoelectronic programmable synapses based on phase change materials for brain-inspired computing.

    Science.gov (United States)

    Kuzum, Duygu; Jeyasingh, Rakesh G D; Lee, Byoungil; Wong, H-S Philip

    2012-05-09

    Brain-inspired computing is an emerging field, which aims to extend the capabilities of information technology beyond digital logic. A compact nanoscale device, emulating biological synapses, is needed as the building block for brain-like computational systems. Here, we report a new nanoscale electronic synapse based on technologically mature phase change materials employed in optical data storage and nonvolatile memory applications. We utilize continuous resistance transitions in phase change materials to mimic the analog nature of biological synapses, enabling the implementation of a synaptic learning rule. We demonstrate different forms of spike-timing-dependent plasticity using the same nanoscale synapse with picojoule level energy consumption.

  15. A Highly Tunable Silicone-Based Magnetic Elastomer with Nanoscale Homogeneity.

    Science.gov (United States)

    Evans, Benjamin A; Fiser, Briana L; Prins, Willem J; Rapp, Daniel J; Shields, Adam R; Glass, Daniel R; Superfine, R

    2012-02-01

    Magnetic elastomers have been widely pursued for sensing and actuation applications. Silicone-based magnetic elastomers have a number of advantages over other materials such as hydrogels, but aggregation of magnetic nanoparticles within silicones is difficult to prevent. Aggregation inherently limits the minimum size of fabricated structures and leads to non-uniform response from structure to structure. We have developed a novel material which is a complex of a silicone polymer (polydimethylsiloxane-co-aminopropylmethylsiloxane) adsorbed onto the surface of magnetite (γ-Fe(2)0(3)) nanoparticles 7-10 nm in diameter. The material is homogenous at very small length scales (< 100 nm) and can be crosslinked to form a flexible, magnetic material which is ideally suited for the fabrication of micro- to nanoscale magnetic actuators. The loading fraction of magnetic nanoparticles in the composite can be varied smoothly from 0 - 50% wt. without loss of homogeneity, providing a simple mechanism for tuning actuator response. We evaluate the material properties of the composite across a range of nanoparticle loading, and demonstrate a magnetic-field-induced increase in compressive modulus as high as 300%. Furthermore, we implement a strategy for predicting the optimal nanoparticle loading for magnetic actuation applications, and show that our predictions correlate well with experimental findings.

  16. High Speed SPM of Functional Materials

    Energy Technology Data Exchange (ETDEWEB)

    Huey, Bryan D. [Univ. of Connecticut, Storrs, CT (United States)

    2015-08-14

    The development and optimization of applications comprising functional materials necessitates a thorough understanding of their static and dynamic properties and performance at the nanoscale. Leveraging High Speed SPM and concepts enabled by it, efficient measurements and maps with nanoscale and nanosecond temporal resolution are uniquely feasible. This includes recent enhancements for topographic, conductivity, ferroelectric, and piezoelectric properties as originally proposed, as well as newly developed methods or improvements to AFM-based mechanical, friction, thermal, and photoconductivity measurements. The results of this work reveal fundamental mechanisms of operation, and suggest new approaches for improving the ultimate speed and/or efficiency, of data storage systems, magnetic-electric sensors, and solar cells.

  17. Negative pressure characteristics of an evaporating meniscus at nanoscale

    Directory of Open Access Journals (Sweden)

    Maroo Shalabh

    2011-01-01

    Full Text Available Abstract This study aims at understanding the characteristics of negative liquid pressures at the nanoscale using molecular dynamics simulation. A nano-meniscus is formed by placing liquid argon on a platinum wall between two nano-channels filled with the same liquid. Evaporation is simulated in the meniscus by increasing the temperature of the platinum wall for two different cases. Non-evaporating films are obtained at the center of the meniscus. The liquid film in the non-evaporating and adjacent regions is found to be under high absolute negative pressures. Cavitation cannot occur in these regions as the capillary height is smaller than the critical cavitation radius. Factors which determine the critical film thickness for rupture are discussed. Thus, high negative liquid pressures can be stable at the nanoscale, and utilized to create passive pumping devices as well as significantly enhance heat transfer rates.

  18. 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.

  19. Conductive Polymer Nanowire Gas Sensor Fabricated by Nanoscale Soft Lithography.

    Science.gov (United States)

    Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

    2017-10-02

    Resistive devices composed of one dimensional nanostructures are promising candidate for next generation gas sensors. However, the large-scale fabrication of nanowires is still a challenge, restricting the commercialization of such type of devices. Here, we reported a highly efficient and facile approach to fabricate poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive type of gas sensor by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate which facilitates the device integration. The nanowire chemiresistive gas sensor is demonstrated for NH3 and NO2 detection at room-temperature and shows a limit of detection at ppb level which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with conventional lithography technique. In comparison with PEDOT:PSS thin film gas sensor, the nanowire gas sensor exhibits a higher sensitivity and much faster response to gas molecules. © 2017 IOP Publishing Ltd.

  20. Monte Carlo simulations of nanoscale focused neon ion beam sputtering.

    Science.gov (United States)

    Timilsina, Rajendra; Rack, Philip D

    2013-12-13

    A Monte Carlo simulation is developed to model the physical sputtering of aluminum and tungsten emulating nanoscale focused helium and neon ion beam etching from the gas field ion microscope. Neon beams with different beam energies (0.5-30 keV) and a constant beam diameter (Gaussian with full-width-at-half-maximum of 1 nm) were simulated to elucidate the nanostructure evolution during the physical sputtering of nanoscale high aspect ratio features. The aspect ratio and sputter yield vary with the ion species and beam energy for a constant beam diameter and are related to the distribution of the nuclear energy loss. Neon ions have a larger sputter yield than the helium ions due to their larger mass and consequently larger nuclear energy loss relative to helium. Quantitative information such as the sputtering yields, the energy-dependent aspect ratios and resolution-limiting effects are discussed.

  1. Nanoscale Properties of Neural Cell Prosthetic and Astrocyte Response

    Science.gov (United States)

    Flowers, D. A.; Ayres, V. M.; Delgado-Rivera, R.; Ahmed, I.; Meiners, S. A.

    2009-03-01

    Preliminary data from in-vivo investigations (rat model) suggest that a nanofiber prosthetic device of fibroblast growth factor-2 (FGF-2)-modified nanofibers can correctly guide regenerating axons across an injury gap with aligned functional recovery. Scanning Probe Recognition Microscopy (SPRM) with auto-tracking of individual nanofibers is used for investigation of the key nanoscale properties of the nanofiber prosthetic device for central nervous system tissue engineering and repair. The key properties under SPRM investigation include nanofiber stiffness and surface roughness, nanofiber curvature, nanofiber mesh density and porosity, and growth factor presentation and distribution. Each of these factors has been demonstrated to have global effects on cell morphology, function, proliferation, morphogenesis, migration, and differentiation. The effect of FGF-2 modification on the key nanoscale properties is investigated. Results from the nanofiber prosthetic properties investigations are correlated with astrocyte response to unmodified and FGF-2 modified scaffolds, using 2D planar substrates as a control.

  2. Nanoscale manipulation of Ge nanowires by ion hammering

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Samuel T [Los Alamos National Laboratory; Romano, Lucia [UNIV OF FLORIDA; Rudawski, Nicholas G [UNIV OF FLORIDA; Holzworth, Monta R [UNIV OF FLORIDA; Jones, Kevin S [UNIV OF FLORIDA; Choi, S G [NREL

    2009-01-01

    Nanowires generated considerable interest as nanoscale interconnects and as active components of both electronic and electromechanical devices. However, in many cases, manipulation and modification of nanowires are required to realize their full potential. It is essential, for instance, to control the orientation and positioning of nanowires in some specific applications. This work demonstrates a simple method to reversibly control the shape and the orientation of Ge nanowires by using ion beams. Initially, crystalline nanowires were partially amorphized by 30 keY Ga+-implantation. After amorphization, viscous flow and plastic deformation occurred due to the ion hammering effect, causing the nanowires to bend toward the beam direction. The bending was reversed multiple times by ion-implanting the opposite side of the nanowires, resulting in straightening of the nanowires and subsequent bending in the opposite direction. This ion hammering effect demonstrates the detailed manipulation of nanoscale structures is possible through the use of ion irradiation.

  3. Polysulfide flow batteries enabled by percolating nanoscale conductor networks.

    Science.gov (United States)

    Fan, Frank Y; Woodford, William H; Li, Zheng; Baram, Nir; Smith, Kyle C; Helal, Ahmed; McKinley, Gareth H; Carter, W Craig; Chiang, Yet-Ming

    2014-01-01

    A new approach to flow battery design is demonstrated wherein diffusion-limited aggregation of nanoscale conductor particles at ∼1 vol % concentration is used to impart mixed electronic-ionic conductivity to redox solutions, forming flow electrodes with embedded current collector networks that self-heal after shear. Lithium polysulfide flow cathodes of this architecture exhibit electrochemical activity that is distributed throughout the volume of flow electrodes rather than being confined to surfaces of stationary current collectors. The nanoscale network architecture enables cycling of polysulfide solutions deep into precipitation regimes that historically have shown poor capacity utilization and reversibility and may thereby enable new flow battery designs of higher energy density and lower system cost. Lithium polysulfide half-flow cells operating in both continuous and intermittent flow mode are demonstrated for the first time.

  4. 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.

  5. GaN nanowire tips for nanoscale atomic force microscopy

    Science.gov (United States)

    Behzadirad, Mahmoud; Nami, Mohsen; Rishinaramagalam, Ashwin K.; Feezell, Daniel F.; Busani, Tito

    2017-05-01

    Imaging of high-aspect-ratio nanostructures with sharp edges and straight walls in nanoscale metrology by atomic force microscopy (AFM) has been challenging due to the mechanical properties and conical geometry of the majority of available commercial tips. Here we report on the fabrication of GaN probes for nanoscale metrology of high-aspect-ratio structures to enhance the resolution of AFM imaging and improve the durability of AFM tips. GaN nanowires were fabricated using bottom-up and top-down techniques and bonded to Si cantilevers to scan vertical trenches on Si substrates. Over several scans, the GaN probes demonstrated excellent durability while scanning uneven structures and showed resolution enhancements in topography images, independent of scan direction, compared to commercial Si tips.

  6. Strategies for Controlled Placement of Nanoscale Building Blocks

    Directory of Open Access Journals (Sweden)

    Koh SeongJin

    2007-01-01

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

  7. Perfect Thermal Emission by Nanoscale Transmission Line Resonators.

    Science.gov (United States)

    Liu, Baoan; Gong, Wei; Yu, Bowen; Li, Pengfei; Shen, Sheng

    2017-02-08

    Thermal radiation with a narrow-band emission spectrum is of great importance in a variety of applications such as infrared sensing, thermophotovoltaics, radiation cooling, and thermal circuits. Although resonant nanophotonic structures such as metamaterials and nanocavities have been demonstrated to achieve the narrow-band thermal emission, maximizing their radiation power toward perfect emission still remains challenging. Here, based on the recently developed quasi-normal mode theory, we prove that thermal emission from a nanoscale transmission line resonator can always be maximized by tuning the waveguiding loss of the resonator or bending the structure. By use of nanoscale transmission line resonators as basic building blocks, we experimentally demonstrate a new type of macroscopic perfect and tunable thermal emitters. Our experimental demonstration in conjunction with the general theoretical framework from the quasi-normal mode theory lays the foundation for designing tunable narrow-band thermal emitters with applications in thermal infrared light sources, thermal management, and infrared sensing and imaging.

  8. Conductive polymer nanowire gas sensor fabricated by nanoscale soft lithography

    Science.gov (United States)

    Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

    2017-12-01

    Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation of gas sensors. However, the large-scale fabrication of nanowires is still challenging, which restricts the commercialization of such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive gas sensors by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate, which facilitates device integration. The nanowire chemiresistive gas sensor is demonstrated for NH3 and NO2 detection at room temperature and shows a limit of detection at ppb level, which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with the conventional lithography technique. In comparison with PEDOT:PSS thin-film gas sensors, the nanowire gas sensor exhibits higher sensitivity and a much faster response to gas molecules.

  9. 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.

  10. Tailorable Stimulated Brillouin Scattering in Nanoscale Silicon Waveguides

    CERN Document Server

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

    2013-01-01

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

  11. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

    2005-01-01

    Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

  12. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

    2008-01-01

    Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

  13. Multiscale computation of wetting transitions on micro/nanoscale solid structures

    Science.gov (United States)

    Colosqui, Carlos; Kavousanakis, Michail; Papathanasiou, Athanasios; Kevrekidis, Ioannis

    2011-11-01

    Modern microfabrication techniques allow the construction of solid surfaces with micro or nanoscale structure. The artificial micro/nanostructure, when properly designed, produces smart surfaces capable of exhibiting surperhydrophobic or superhydrophilic wetting properties in an addressable manner The design and control of transitions between superhydrophobic and superhydrophilic states using minimal external actuation (e.g. via electro-wetting, UV radiation, etc.) is an active research area with enormous impact in microfluidics and materials science. In this work, we demonstrate a computational methodology that allows microscopic or mesoscopic models to perform numerical continuation and stability analysis at macroscopic level. The method's ability to compute stable and unstable wetting states via accurate dynamic simulations is extremely valuable for the optimal engineering design of micro/nanostructures. The computational methodology is demonstrated by employing a novel lattice Boltzmann model that captures critical interfacial phenomena such as disjoining pressure and vapor adsorption at the solid-fluid surface.

  14. Gate leakage current partitioning in nanoscale double gate MOSFETs, using compact analytical model

    Science.gov (United States)

    Darbandy, Ghader; Lime, François; Cerdeira, Antonio; Estrada, Magali; Garduño, Salvador Ivan; Iñiguez, Benjamin

    2012-09-01

    This paper presents a compact gate leakage current partitioning model for nanoscale Double Gate (DG) MOSFETs, using analytical models of the direct tunneling gate leakage current. Gate leakage current becomes important and an essential aspect of MOSFET modeling as the gate oxide thickness is scaled down to 1 nm and below in advanced CMOS processes. We considered an ideal interface (ideal case without an interfacial layer) and two layers high k dielectric materials as gate insulators. In the case of two layers, a thin layer of SiO2 as an interfacial layer is considered. The results of the gate current partitioning components into drain and source show good agreement with 2D TCAD numerical device simulation (Silvaco Atlas).

  15. Kinetic inductance driven nanoscale 2D and 3D THz transmission lines.

    Science.gov (United States)

    Mousavi, S Hossein; Williamson, Ian A D; Wang, Zheng

    2016-05-03

    We examine the unusual dispersion and attenuation of transverse electromagnetic waves in the few-THz regime on nanoscale graphene and copper transmission lines. Conventionally, such propagation has been considered to be highly dispersive, due to the RC time constant-driven voltage diffusion below 1 THz and plasmonic effects at higher optical frequencies. Our numerical modeling across the microwave, THz, and optical frequency ranges reveals that the conductor kinetic inductance creates an ultra-broadband linear-dispersion and constant-attenuation region in the THz regime. This so-called LC region is an ideal characteristic that is known to be absent in macro-scale transmission lines. The kinetic-LC frequency range is dictated by the structural dimensionality and the free-carrier scattering rate of the conductor material. Moreover, up to 40x wavelength reduction is observed in graphene transmission lines.

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

    Science.gov (United States)

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

    2015-01-01

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

  17. Nanoscale and femtosecond optical autocorrelator based on a single plasmonic nanostructure

    Science.gov (United States)

    Melentiev, P. N.; Afanasiev, A. E.; Tausenev, A. V.; Konyaschenko, A. V.; Klimov, V. V.; Balykin, V. I.

    2014-10-01

    We demonstrated a nanoscale size, ultrafast and multiorder optical autocorrelator with a single plasmonic nanostructure for measuring the spatio-temporal dynamics of femtosecond laser light. As a nanostructure, we use a split hole resonator (SHR), which was made in an aluminium nanofilm. The Al material yields the fastest response time (100 as). The SHR nanostructure ensures a high nonlinear optical efficiency of the interaction with laser radiation, which leads to (1) the second, (2) the third harmonics generation and (3) the multiphoton luminescence, which, in turn, are used to perform multi-order autocorrelation measurements. The nano-sized SHR makes it possible to conduct autocorrelation measurements (i) with a subwavelength spatial resolution and (ii) with no significant influence on the duration of the laser pulse. The time response realized by the SHR nanostructure is about 10 fs.

  18. Effect of micro- and nanoscale topography on the adhesion of bacterial cells to solid surfaces.

    Science.gov (United States)

    Hsu, Lillian C; Fang, Jean; Borca-Tasciuc, Diana A; Worobo, Randy W; Moraru, Carmen I

    2013-04-01

    Attachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, including Escherichia coli, Listeria innocua, and Pseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.

  19. Recent Approaches to Controlling the Nanoscale Morphology of Polymer-Based Bulk-Heterojunction Solar Cells

    Directory of Open Access Journals (Sweden)

    Abdulra'uf Lukman Bola

    2013-11-01

    Full Text Available The need for clean, inexpensive and renewable energy has increasingly turned research attention towards polymer photovoltaic cells. However, the performance efficiency of these devices is still low in comparison with silicon-based devices. The recent introduction of new materials and processing techniques has resulted in a remarkable increase in power-conversion efficiency, with a value above 10%. Controlling the interpenetrating network morphology is a key factor in obtaining devices with improved performance. This review focuses on the influence of controlled nanoscale morphology on the overall performance of bulk-heterojunction (BHJ photovoltaic cells. Strategies such as the use of solvents, solvent annealing, polymer nanowires (NWs, and donor–acceptor (D–A blend ratios employed to control the active-layer morphologies are all discussed.

  20. New X-Ray Technique to Characterize Nanoscale Precipitates in Aged Aluminum Alloys

    Science.gov (United States)

    Sitdikov, V. D.; Murashkin, M. Yu.; Valiev, R. Z.

    2017-09-01

    This paper puts forward a new technique for measurement of x-ray patterns, which enables to solve the problem of identification and determination of precipitates (nanoscale phases) in metallic alloys of the matrix type. The minimum detection limit of precipitates in the matrix of the base material provided by this technique constitutes as little as 1%. The identification of precipitates in x-ray patterns and their analysis are implemented through a transmission mode with a larger radiation area, longer holding time and higher diffractometer resolution as compared to the conventional reflection mode. The presented technique has been successfully employed to identify and quantitatively describe precipitates formed in the Al alloy of the Al-Mg-Si system as a result of artificial aging. For the first time, the x-ray phase analysis has been used to identify and measure precipitates formed during the alloy artificial aging.