WorldWideScience

Sample records for single national structure

  1. Single Family Loan Sale Initiative - National Offering

    Data.gov (United States)

    Department of Housing and Urban Development — The FHA Office of Housing is conducting a series of mortgage loan sales under the Single Family Loan Sale (SFLS) Initiative. The current sales structure consists of...

  2. A structured record to implement the national guidelines for diabetes ...

    African Journals Online (AJOL)

    A draft of the structured record was developed at a single-pilot CHC in the Western Cape. Focus group discussions established the core requirements for a structured record. Process, result and structural indicators in line with the national Guidelines were considered for inclusion in the draft record. This draft record was then ...

  3. Euro Area: Single Currency - National Money Creation

    OpenAIRE

    Stefan Kooths; Björn van Roye

    2012-01-01

    The Eurosystem has been pursuing a crisis management policy for more than four years now. This policy aims primarily at maintaining financial stability in the euro area by providing vast liquidity support to commercial banks that are operating in nationally segmented banking systems. As a side effect, the national central banks substitute money market operations for cross-border capital flows. The national central banks are thus increasingly engaging in substantial balance-of-payments financi...

  4. Nuclear structure and the single charge exchange

    International Nuclear Information System (INIS)

    Oset, E.; Strottman, D.

    1979-01-01

    The influence of nuclear structure on meson-induced single-charge-exchange reactions on light nuclei is discussed within the context of the Glauber approximation. Selection rules which are expected to be approximately obeyed in elastic and inelastic pion and kaon scattering are proposed. Theoretical predictions are presented for (π + ,π 0 ) and (K + ,K 0 ) reactions on 13 C. 14 figures

  5. Single crystal surface structure by bragg scattering

    DEFF Research Database (Denmark)

    Nielsen, Mogens

    1985-01-01

    X-ray diffraction is becoming an important tool in the measurements of surface structures. Single crystalline samples are used as in Low Energy Electron Diffraction (LEED)-studies. The X-ray technique is somewhat more involved due to the need of bright, collimated photon sources, in general...

  6. Strength of single-pole utility structures

    Science.gov (United States)

    Ronald W. Wolfe

    2006-01-01

    This section presents three basic methods for deriving and documenting Rn as an LTL value along with the coefficient of variation (COVR) for single-pole structures. These include the following: 1. An empirical analysis based primarily on tests of full-sized poles. 2. A theoretical analysis of mechanics-based models used in...

  7. Changing optical band structure with single photons

    Science.gov (United States)

    Albrecht, Andreas; Caneva, Tommaso; Chang, Darrick E.

    2017-11-01

    Achieving strong interactions between individual photons enables a wide variety of exciting possibilities in quantum information science and many-body physics. Cold atoms interfaced with nanophotonic structures have emerged as a platform to realize novel forms of nonlinear interactions. In particular, when atoms are coupled to a photonic crystal waveguide, long-range atomic interactions can arise that are mediated by localized atom-photon bound states. We theoretically show that in such a system, the absorption of a single photon can change the band structure for a subsequent photon. This occurs because the first photon affects the atoms in the chain in an alternating fashion, thus leading to an effective period doubling of the system and a new optical band structure for the composite atom-nanophotonic system. We demonstrate how this mechanism can be engineered to realize a single-photon switch, where the first incoming photon switches the system from being highly transmissive to highly reflective, and analyze how signatures can be observed via non-classical correlations of the outgoing photon field.

  8. Japan's National Security: Structures, norms, and policies

    International Nuclear Information System (INIS)

    Katzenstein, P.J.; Okawara, N.

    1993-01-01

    Japan's national security policy has two distinctive aspects that deserve analysis. First, Japan's definition of national security goes far beyond traditional military notions. National security is viewed in comprehensive terms that also include economic and political dimensions. The second feature of Japan's security policy worth explanation is a distinctive mixture of flexibility and rigidity in the process of policy adaptation to change: flexibility on issues of economic security, rigidity on issues of military security, and flexibility combined with rigidity on issues of political security. With the end of the Cold War and changes in the structure of the international system, it is only natural that we ask whether and how Japan's national security policy will change as well. Optimists insist that the Asian balance of power and the US-Japan relationship will make Japan aspire to be a competitive, noninterventionist trading state that heeds the universal interest of peace and profit rather than narrow aspirations for national power. Pessimists warn us instead that the new international system will finally confirm Herman Kahn's prediction of 1970: Japan will quickly change to the status of a nuclear superpower, spurred perhaps by what some see as a dangerous rise of Japanese militarism in the 1970s and 1980s

  9. Structural Encoding of Static Single Assignment Form

    DEFF Research Database (Denmark)

    Gal, Andreas; Probst, Christian; Franz, Michael

    2005-01-01

    Static Single Assignment (SSA) form is often used as an intermediate representation during code optimization in Java Virtual Machines. Recently, SSA has successfully been used for bytecode verification. However, constructing SSA at the code consumer is costly. SSAbased mobile code transport formats...... Java bytecode. While the resulting bytecode sequence can still be directly executed by traditional Virtual Machines, our novel VM can infer SSA form and confirm its safety with virtually no overhead....

  10. USGS Structures Overlay Map Service from The National Map - National Geospatial Data Asset (NGDA) USGS National Structures Dataset

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — USGS Structures from The National Map (TNM) consists of data to include the name, function, location, and other core information and characteristics of selected...

  11. Single bunch transfer system for the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Sheehan, J.; Singh, O.; Rambo, W.

    1983-01-01

    The accelerator system at the National Synchrotron Light Source consists of an S-band 85 MeV linac and three synchrotron rings. The electron beam from the linac is accelerated by the booster ring to 600 MeV and transferred to one of the two storage rings. The smaller of the two rings operates between 300 and 800 MeV emtting photons in the vacuum ultraviolet (VUV), while the larger storage ring operates up to 2.5 GeV and emits photons in the x-ray spectrum. A system is described for loading the storage rings by filling a single-phase space bunch in the booster ring and transferring it at the end of each booster cycle into a selected bucket in one of the storage rings. By controlling the timing of the transfer on successive transfer cycles, many fill patterns may be obtained

  12. Three-dimensional structure determination from a single view.

    Science.gov (United States)

    Raines, Kevin S; Salha, Sara; Sandberg, Richard L; Jiang, Huaidong; Rodríguez, Jose A; Fahimian, Benjamin P; Kapteyn, Henry C; Du, Jincheng; Miao, Jianwei

    2010-01-14

    The ability to determine the structure of matter in three dimensions has profoundly advanced our understanding of nature. Traditionally, the most widely used schemes for three-dimensional (3D) structure determination of an object are implemented by acquiring multiple measurements over various sample orientations, as in the case of crystallography and tomography, or by scanning a series of thin sections through the sample, as in confocal microscopy. Here we present a 3D imaging modality, termed ankylography (derived from the Greek words ankylos meaning 'curved' and graphein meaning 'writing'), which under certain circumstances enables complete 3D structure determination from a single exposure using a monochromatic incident beam. We demonstrate that when the diffraction pattern of a finite object is sampled at a sufficiently fine scale on the Ewald sphere, the 3D structure of the object is in principle determined by the 2D spherical pattern. We confirm the theoretical analysis by performing 3D numerical reconstructions of a sodium silicate glass structure at 2 A resolution, and a single poliovirus at 2-3 nm resolution, from 2D spherical diffraction patterns alone. Using diffraction data from a soft X-ray laser, we also provide a preliminary demonstration that ankylography is experimentally feasible by obtaining a 3D image of a test object from a single 2D diffraction pattern. With further development, this approach of obtaining complete 3D structure information from a single view could find broad applications in the physical and life sciences.

  13. Functionalization of Single Layer MoS$_2$ Honeycomb Structures

    OpenAIRE

    Ataca, C.; Ciraci, S.

    2010-01-01

    Based on the first-principles plane wave calculations, we studied the functionalization of the two-dimensional single layer MoS$_2$ structure via adatom adsorption and vacancy defect creation. Minimum energy adsorption sites are determined for sixteen different adatoms, each gives rise to diverse properties. Bare, single layer MoS$_2$, which is normally a nonmagnetic, direct band gap semiconductor, attains a net magnetic moment upon adsorption of specific transition metal atoms, as well as si...

  14. The scale dependence of single-nucleon shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Somà, V., E-mail: vittorio.soma@cea.fr [Centre de Saclay, IRFU/Service de Physique Nucléaire, 91191 Gif-sur-Yvette (France); Duguet, T. [Centre de Saclay, IRFU/Service de Physique Nucléaire, 91191 Gif-sur-Yvette (France); KU Leuven, Instituut voor Kern-en Stralingsfysica, 3001 Leuven (Belgium); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States); NSCL, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Hergert, H. [NSCL, Michigan State University, East Lansing, Michigan 48824-1321 (United States); The Ohio State University, Columbus, Ohio 43210 (United States); Holt, J. D. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)

    2015-10-15

    We address the scale dependence of (effective) single-particle energies, non-observable quantities that are commonly used for interpreting nuclear structure observables measured in experiments and computed in many-body theories. We first demonstrate their scale dependence on a formal level, making them intrinsically theoretical objects, before illustrating this point via ab initio calculations in the oxygen isotopes. Finally, we consider a modified definition of effective single-particle energy and investigate its running properties.

  15. Overview of Hanford Single Shell Tank (SST) Structural Integrity

    Energy Technology Data Exchange (ETDEWEB)

    Rast, Richard S.; Washenfelder, Dennis J.; Johnson, Jeremy M.

    2013-11-14

    To improve the understanding of the single-shell tanks (SSTs) integrity, Washington River Protection Solutions, LLC (WRPS), the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank Integrity Project (SSTIP) in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration, Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The structural integrity of the tanks is a key element in completing the cleanup mission at the Hanford Site. There are eight primary recommendations related to the structural integrity of Hanford Single-Shell Tanks. Six recommendations are being implemented through current and planned activities. The structural integrity of the Hanford is being evaluated through analysis, monitoring, inspection, materials testing, and construction document review. Structural evaluation in the form of analysis is performed using modern finite element models generated in ANSYS. The analyses consider in-situ, thermal, operating loads and natural phenomena such as earthquakes. Structural analysis of 108 of 149 Hanford Single-Shell Tanks has concluded that the tanks are structurally sound and meet current industry standards. Analysis of the remaining Hanford Single-Shell Tanks is scheduled for FY2014. Hanford Single-Shell Tanks are monitored through a dome deflection program. The program looks for deflections of the tank dome greater than 1/4 inch. No such deflections have been recorded. The tanks are also subjected to visual inspection. Digital cameras record the interior surface of

  16. Structural perfection and residual electric resistance of tungsten single crystals

    International Nuclear Information System (INIS)

    Tagirova, D.M.; Dyakina, V.P.; Startsev, V.E.; Esin, V.O.

    1997-01-01

    A study was made into residual relative resistance (RRR) and structural perfection (SP) of tungsten single crystals, grown by electron beam zone melting using seeding crystals of several orientations, namely, , , , . The single crystals were of 99.98 and 99.9995 wt.% purity. The RRR value is found to depend on crystallographic orientation of an axis of crystal growth and to correlate with SP. Single crystals of different purity are differ in the nature of orientational dependences. It is shown that the correlation between RRR and SP of crystals is mainly due to conduction electron scattering by subgrain boundaries (internal size effect)

  17. RF Breakdown in Normal Conducting Single-Cell Structures

    International Nuclear Information System (INIS)

    Dolgashev, V.A.; Nantista, C.D.; Tantawi, S.G.; Higashi, Y.; Higo, T.

    2006-01-01

    Operating accelerating gradient in normal conducting accelerating structures is often limited by rf breakdown. The limit depends on multiple parameters, including input rf power, rf circuit, cavity shape and material. Experimental and theoretical study of the effects of these parameters on the breakdown limit in full scale structures is difficult and costly. We use 11.4 GHz single-cell traveling wave and standing wave accelerating structures for experiments and modeling of rf breakdown behavior. These test structures are designed so that the electromagnetic fields in one cell mimic the fields in prototype multicell structures for the X-band linear collider. Fields elsewhere in the test structures are significantly lower than that of the single cell. The setup uses matched mode converters that launch the circular TM 01 mode into short test structures. The test structures are connected to the mode launchers with vacuum rf flanges. This setup allows economic testing of different cell geometries, cell materials and preparation techniques with short turn-around time. Simple 2D geometry of the test structures simplifies modeling of the breakdown currents and their thermal effects

  18. Evolution of single-particle structure of silicon isotopes

    Science.gov (United States)

    Bespalova, O. V.; Fedorov, N. A.; Klimochkina, A. A.; Markova, M. L.; Spasskaya, T. I.; Tretyakova, T. Yu.

    2018-01-01

    New data on proton and neutron single-particle energies E_{nlj} of Si isotopes with neutron number N from 12 to 28 as well as occupation probabilities N_{nlj} of single-particle states of stable isotopes 28, 30Si near the Fermi energy were obtained by the joint evaluation of the stripping and pick-up reaction data and excited state decay schemes of neighboring nuclei. The evaluated data indicate the following features of single-particle structure evolution: persistence of Z = 14 subshell closure with N increase, the new magicity of the number N = 16, and the conservation of the magic properties of the number N = 20 in Si isotopic chain. The features were described by the dispersive optical model. The calculation also predicts the weakening of N = 28 shell closure and demonstrates evolution of a bubble-like structure of the proton density distributions in neutron-rich Si isotopes.

  19. Magnetic structure of URhSi single crystal

    Czech Academy of Sciences Publication Activity Database

    Prokeš, K.; Andreev, Alexander V.; Honda, F.; Sechovský, V.

    2003-01-01

    Roč. 261, - (2003), s. 131-138 ISSN 0304-8853 R&D Projects: GA ČR GA202/02/0739 Institutional research plan: CEZ:AV0Z1010914 Keywords : URhSi single crystal * magnetization * neutron diffraction * magnetic structure determination Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.910, year: 2003

  20. National Minority Organisations in Prague: structure, competence

    Czech Academy of Sciences Publication Activity Database

    Sulitka, Andrej; Uherek, Zdeněk

    2015-01-01

    Roč. 25, č. 5 (2015), s. 3-17 ISSN 0862-8351 Institutional support: RVO:68378076 Keywords : ethnology * social anthropology * Czech Republic * minority * national policy Subject RIV: AC - Archeology, Anthropology, Ethnology

  1. Managing health expenditure inflation under a single-payer system: Taiwan's National Health Insurance.

    Science.gov (United States)

    Yip, Winnie C; Lee, Yue-Chune; Tsai, Shu-Ling; Chen, Bradley

    2017-11-16

    As nations strive to achieve and sustain universal health coverage (UHC), they seek answers as to what health system structures are more effective in managing health expenditure inflation. A fundamental macro-level choice a nation has to make is whether to adopt a single- or a multiple-payer health system. Using Taiwan's National Health Insurance (NHI) as a case, this paper examines how a single-payer system manages its health expenditure growth and draws lessons for other countries whose socioeconomic development is similar to Taiwan's. Our analyses show that as a single payer, Taiwan's NHI is able to exercise its monopsony power to manage its health expenditure growth. This is achieved primarily through the adoption of a system-wide global budget. The global budget sets a hard aggregate budget cap to limit NHI's total spending to its expected revenue, with the annual budget growth rate established by a process of negotiation among key stakeholders. The global budget system is complemented by comprehensive and continuous monitoring and review of encounter records of all providers and patients, enabled by the NHI's advanced information technology. However, by paying its providers using a point-based fee schedule, Taiwan's NHI suffers from inefficient service provision. In particular, providers have incentives to increase use of services and drugs with positive profit margins. Furthermore, Taiwan demonstrates that its control of NHI expenditure growth might be leading it to inadequately meet the changing needs of the population, resulting in the rapid growth of private insurance to cover services excluded or not fully covered by the NHI. If this trend persists and results in a two-tier system, Taiwan's NHI may risk compromising the equity it has achieved in the past two decades. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hybrid Testing of Composite Structures with Single-Axis Control

    DEFF Research Database (Denmark)

    Waldbjørn, Jacob Paamand; Høgh, Jacob Herold; Stang, Henrik

    2013-01-01

    Hybrid testing is a substructuring technique where a structure is emulated by modelling a part of it in a numerical model while testing the remainder experimentally. Previous research in hybrid testing has been performed on multi-component structures e.g. damping fixtures, however in this paper...... a hybrid testing platform is introduced for single-component hybrid testing. In this case, the boundary between the numerical model and experimental setup is defined by multiple Degrees-Of-Freedoms (DOFs) which highly complicate the transferring of response between the two substructures. Digital Image...... Correlation (DIC) is therefore implemented for displacement control of the experimental setup. The hybrid testing setup was verified on a multicomponent structure consisting of a beam loaded in three point bending and a numerical structure of a frame. Furthermore, the stability of the hybrid testing loop...

  3. Luminescence properties of piezoelectric single crystals with langasite structure

    International Nuclear Information System (INIS)

    Itoh, Minoru; Takagi, Shinya; Kitaura, Mamoru; Fujita, Masami; Endo, Naoyuki

    2007-01-01

    Luminescence properties of single crystals of langasite (LGS), langataite (LGT), and langanite (LGN) are investigated at 5 K by using synchrotron radiation as an exciting light source. Two emission bands are observed at 420 and 500 nm in LGS, at 410 and 460 nm in LGT, and at 500 and 535 nm in LGN. The origin of these bands is discussed by reference to the electronic structure of LGS

  4. Single Scattering Detection in Turbin Media Using Single-Phase Structured Illumination Filtering

    Science.gov (United States)

    Berrocal, E.; Johnsson, J.; Kristensson, E.; Alden, M.

    2012-05-01

    This work shows a unique possibility of visualizing the exponential intensity decay due to light extinction, when laser adiation propagates through a homogeneous scattering edium. This observation implies that the extracted intensity mostly riginates from single scattering events. The filtering of this single light scattering intensity is performed by means of a single-phase structured illumination filtering approach. Results from numerical Monte Carlo simulation confirm the experimental findings for an extinction coefficient of μ_e = 0.36 mm^-1. This article demonstrates an original and reliable way of measuring the extinction coefficient of particulate turbid media based on sidescattering imaging. Such an approach has capabilities to replace the commonly used transmission measurement within the intermediate single-to multiple scattering regime where the optical depth ranges between 1 procedure and set-up. Applications of the technique has potential in probing challenging homogeneous scattering media, such as biomedical tissues, turbid emulsions, etc, in situations where dilution cannot be applied and where conventional transmission measurements fail.

  5. Overview Of Hanford Single Shell Tank (SST) Structural Integrity - 12123

    International Nuclear Information System (INIS)

    Rast, R.S.; Rinker, M.W.; Washenfelder, D.J.; Johnson, J.B.

    2012-01-01

    To improve the understanding of the single-shell tanks (SSTs) integrity, Washington River Protection Solutions, LLC (WRPS), the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank Integrity Project in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration. Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The structural integrity of the tanks is a key element in completing the cleanup mission at the Hanford Site. There are eight primary recommendations related to the structural integrity of Hanford SSTs. Six recommendations are being implemented through current and planned activities. The structural integrity of the Hanford SSTs is being evaluated through analysis, monitoring, inspection, materials testing, and construction document review. Structural evaluation in the form of analysis is performed using modern finite element models generated in ANSYS(reg s ign) The analyses consider in-situ, thermal, operating loads and natural phenomena such as earthquakes. Structural analysis of 108 of 149 Hanford SSTs has concluded that the tanks are structurally sound and meet current industry standards. Analyses of the remaining Hanford SSTs are scheduled for FY2013. Hanford SSTs are monitored through a dome deflection program. The program looks for deflections of the tank dome greater than 1/4 inch. No such deflections have been recorded. The tanks are also subjected to visual inspection. Digital cameras record the interior surface of the concrete tank domes, looking for cracks and

  6. OVERVIEW OF HANFORD SINGLE SHELL TANK (SST) STRUCTURAL INTEGRITY - 12123

    Energy Technology Data Exchange (ETDEWEB)

    RAST RS; RINKER MW; WASHENFELDER DJ; JOHNSON JB

    2012-01-25

    To improve the understanding of the single-shell tanks (SSTs) integrity, Washington River Protection Solutions, LLC (WRPS), the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank Integrity Project in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration. Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The structural integrity of the tanks is a key element in completing the cleanup mission at the Hanford Site. There are eight primary recommendations related to the structural integrity of Hanford SSTs. Six recommendations are being implemented through current and planned activities. The structural integrity of the Hanford SSTs is being evaluated through analysis, monitoring, inspection, materials testing, and construction document review. Structural evaluation in the form of analysis is performed using modern finite element models generated in ANSYS{reg_sign} The analyses consider in-situ, thermal, operating loads and natural phenomena such as earthquakes. Structural analysis of 108 of 149 Hanford SSTs has concluded that the tanks are structurally sound and meet current industry standards. Analyses of the remaining Hanford SSTs are scheduled for FY2013. Hanford SSTs are monitored through a dome deflection program. The program looks for deflections of the tank dome greater than 1/4 inch. No such deflections have been recorded. The tanks are also subjected to visual inspection. Digital cameras record the interior surface of the concrete tank domes, looking for cracks and

  7. From Protein Structure to Function via Single Crystal Optical Spectroscopy

    Directory of Open Access Journals (Sweden)

    Luca eRonda

    2015-04-01

    Full Text Available The more than 100.000 protein structures determined by X-ray crystallography provide a wealth of information for the characterization of biological processes at the molecular level. However, several crystallographic artifacts, including conformational selection, crystallization conditions and radiation damages, may affect the quality and the interpretation of the electron density map, thus limiting the relevance of structure determinations. Moreover, for most of these structures no functional data have been obtained in the crystalline state, thus posing serious questions on their validity in the inference for protein mechanisms. In order to solve these issues, spectroscopic methods have been applied for the determination of equilibrium and kinetic properties of proteins in the crystalline state. These methods are UV-vis spectrophotometry, spectrofluorimetry, IR, EPR, Raman and resonance Raman spectroscopy. Some of these approaches have been implemented with on-line instruments at X-ray synchrotron beamlines. Here, we provide an overview of investigations predominantly carried out in our laboratory by single crystal polarized absorption UV-vis microspectrophotometry, the most applied technique for the functional characterization of proteins in the crystalline state. Studies on hemoglobins, pyridoxal 5’-phosphate dependent enzymes and green fluorescent protein in the crystalline state have addressed key biological issues, leading to either straightforward structure-function correlations or limitations to structure-based mechanisms.

  8. Single-Walled Carbon-Nanotubes-Based Organic Memory Structures

    Directory of Open Access Journals (Sweden)

    Sundes Fakher

    2016-09-01

    Full Text Available The electrical behaviour of organic memory structures, based on single-walled carbon-nanotubes (SWCNTs, metal–insulator–semiconductor (MIS and thin film transistor (TFT structures, using poly(methyl methacrylate (PMMA as the gate dielectric, are reported. The drain and source electrodes were fabricated by evaporating 50 nm gold, and the gate electrode was made from 50 nm-evaporated aluminium on a clean glass substrate. Thin films of SWCNTs, embedded within the insulating layer, were used as the floating gate. SWCNTs-based memory devices exhibited clear hysteresis in their electrical characteristics (capacitance–voltage (C–V for MIS structures, as well as output and transfer characteristics for transistors. Both structures were shown to produce reliable and large memory windows by virtue of high capacity and reduced charge leakage. The hysteresis in the output and transfer characteristics, the shifts in the threshold voltage of the transfer characteristics, and the flat-band voltage shift in the MIS structures were attributed to the charging and discharging of the SWCNTs floating gate. Under an appropriate gate bias (1 s pulses, the floating gate is charged and discharged, resulting in significant threshold voltage shifts. Pulses as low as 1 V resulted in clear write and erase states.

  9. Single-Walled Carbon-Nanotubes-Based Organic Memory Structures.

    Science.gov (United States)

    Fakher, Sundes; Nejm, Razan; Ayesh, Ahmad; Al-Ghaferi, Amal; Zeze, Dagou; Mabrook, Mohammed

    2016-09-02

    The electrical behaviour of organic memory structures, based on single-walled carbon-nanotubes (SWCNTs), metal-insulator-semiconductor (MIS) and thin film transistor (TFT) structures, using poly(methyl methacrylate) (PMMA) as the gate dielectric, are reported. The drain and source electrodes were fabricated by evaporating 50 nm gold, and the gate electrode was made from 50 nm-evaporated aluminium on a clean glass substrate. Thin films of SWCNTs, embedded within the insulating layer, were used as the floating gate. SWCNTs-based memory devices exhibited clear hysteresis in their electrical characteristics (capacitance-voltage (C-V) for MIS structures, as well as output and transfer characteristics for transistors). Both structures were shown to produce reliable and large memory windows by virtue of high capacity and reduced charge leakage. The hysteresis in the output and transfer characteristics, the shifts in the threshold voltage of the transfer characteristics, and the flat-band voltage shift in the MIS structures were attributed to the charging and discharging of the SWCNTs floating gate. Under an appropriate gate bias (1 s pulses), the floating gate is charged and discharged, resulting in significant threshold voltage shifts. Pulses as low as 1 V resulted in clear write and erase states.

  10. Tg and Structural Recovery of Single Ultrathin Films

    Science.gov (United States)

    Simon, Sindee

    The behavior of materials confined at the nanoscale has been of considerable interest over the past two decades. Here, the focus is on recent results for single polystyrene ultrathin films studied with ultrafast scanning chip calorimetry. The Tg depression of a 20 nm-thick high-molecular-weight polystyrene film is found to be a function of cooling rate, decreasing with increasing cooling rate; whereas, at high enough cooling rates (e.g., 1000 K/s), Tg is the same as the bulk within the error of the measurements. Structural recovery is also performed with chip calorimetry as a function of aging time and temperature, and the evolution of the fictive temperature is followed. The advantages of the Flash DSC include sufficient sensitivity to measure enthalpy recovery for a single 20 nm-thick film, as well as extension of the measurements to aging temperatures as high as 15 K above nominal Tg and to aging times as short as 0.01 s. The aging behavior and relaxation time-temperature map for single ultrathin films are compared to those for bulk material. Comparison to behavior in other geometries will also be discussed.

  11. Proceedings of second national workshop on nuclear structure physics

    International Nuclear Information System (INIS)

    Chintalapudi, S.N.; Jain, A.K.

    1995-01-01

    The Second National Workshop on Nuclear Structure Physics was held at Calcutta during February 7-10 1995. The topics discussed have been quite broad based and covered many areas of nuclear structure physics and radiochemistry. Papers relevant to INIS are indexed separately

  12. Single Crystalline Cadmium Sulfide Nanowires with Branched Structure

    Directory of Open Access Journals (Sweden)

    Lu Qingyi

    2009-01-01

    Full Text Available Abstract In this article, we report the synthesis of branched single crystal CdS nanowires. This branched CdS nanostructure is prepared by a simple surfactant-directing method, which is of particular interest as it uses readily available reagents and provides a convenient route to high-yield single crystal nanowires but with branched shape. These branched nanowires have an average diameter of about 40 nm and length up to several micrometers. A possible mechanism has been proposed and the addition of surfactant dodecylthiol into the two mixed-solvents would play an importance effect on the structure of the product. Based on the mechanism, by controlling the synthesis conditions, such as the ratios between the surfactant, inorganic solvent, and organic solvent, other kinds of nanostructures based on CdS nanowires were also prepared. Photoluminescence (PL measurement reveals that the branched CdS nanowires have a strong emission at about 700 nm which might be due to its special structure.

  13. Understanding surface structure and chemistry of single crystal lanthanum aluminate

    KAUST Repository

    Pramana, Stevin S.

    2017-03-02

    The surface crystallography and chemistry of a LaAlO3 single crystal, a material mainly used as a substrate to deposit technologically important thin films (e.g. for superconducting and magnetic devices), was analysed using surface X-ray diffraction and low energy ion scattering spectroscopy. The surface was determined to be terminated by Al-O species, and was significantly different from the idealised bulk structure. Termination reversal was not observed at higher temperature (600 °C) and chamber pressure of 10−10 Torr, but rather an increased Al-O occupancy occurred, which was accompanied by a larger outwards relaxation of Al from the bulk positions. Changing the oxygen pressure to 10−6 Torr enriched the Al site occupancy fraction at the outermost surface from 0.245(10) to 0.325(9). In contrast the LaO, which is located at the next sub-surface atomic layer, showed no chemical enrichment and the structural relaxation was lower than for the top AlO2 layer. Knowledge of the surface structure will aid the understanding of how and which type of interface will be formed when LaAlO3 is used as a substrate as a function of temperature and pressure, and so lead to improved design of device structures.

  14. A Review of Structure Construction of Silk Fibroin Biomaterials from Single Structures to Multi-Level Structures

    Directory of Open Access Journals (Sweden)

    Yu Qi

    2017-03-01

    Full Text Available The biological performance of artificial biomaterials is closely related to their structure characteristics. Cell adhesion, migration, proliferation, and differentiation are all strongly affected by the different scale structures of biomaterials. Silk fibroin (SF, extracted mainly from silkworms, has become a popular biomaterial due to its excellent biocompatibility, exceptional mechanical properties, tunable degradation, ease of processing, and sufficient supply. As a material with excellent processability, SF can be processed into various forms with different structures, including particulate, fiber, film, and three-dimensional (3D porous scaffolds. This review discusses and summarizes the various constructions of SF-based materials, from single structures to multi-level structures, and their applications. In combination with single structures, new techniques for creating special multi-level structures of SF-based materials, such as micropatterning and 3D-printing, are also briefly addressed.

  15. Structure of cleaved (001) USb2 single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shao-ping [Los Alamos National Laboratory; Hawley, Marilyn [Los Alamos National Laboratory; Bauer, Eric D [Los Alamos National Laboratory; Stockum, Phil B [STANFORD UNIV.; Manoharan, Hari C [STANFORD UNIV

    2009-01-01

    We have achieved what we believe to be the first atomic resolution STM images for a uranium compound taken at room temperature. The a, b, and c lattice parameters in the images confirm that the USb{sub 2} crystals cleave on the (001) basal plane as expected. The a and b dimensions were equal, with the atoms arranged in a cubic pattern. Our calculations indicate a symmetric cut between Sb planes to be the most favorable cleavage plane and U atoms to be responsible for most of the DOS measured by STM. Some strange features observed in the STM will be discussed in conjunction with ab initio calculations. The purpose of this work is to demonstrate the power of scanning tunneling microscopy (STM) techniques combined with a theoretical underpinning to determine the surface atomic structure and properties of actinide materials, such as the quasi 2-dimensional uranium dipnictide USb{sub 2} single crystal, thereby contributing to the understanding of their surface structural and electronic properties. The members of this interesting UX{sub 2} (X=P, As, Sb, Bi) series of compounds display dual localized and itinerant 5f electron behavior within the same compound due to the hybridization of the 5f orbitals with the conduction band. With the exception of UO{sub 2}, which has to be studied at elevated temperature to generate enough carriers for STM imaging, STM techniques have not been applied successfully to the characterization of the surface atomic structure of any other single crystal actinide compound, to the best of our knowledge. However, STM has been used to a limited extent for the study of some cerium compounds. STM probes electronic properties at the atomic level and can directly provide information about the local density of filled and empty states (LDOS) states simultaneously. A STM topograph provides the local atomic arrangement and spacing of the atoms on the surface, local defect structures (e.g. steps, vacancies, and kink sites) and the presence of contaminants

  16. Twinning structures in near-stoichiometric lithium niobate single crystals

    International Nuclear Information System (INIS)

    Yao, Shuhua; Chen, Yanfeng

    2010-01-01

    A near-stoichiometric lithium niobate single crystal has been grown by the Czochralski method in a hanging double crucible with a continuous powder supply system. Twins were found at one of the three characteristic growth ridges of the as-grown crystal. The twin structure was observed and analyzed by transmission synchrotron topography. The image shifts ΔX and ΔY in the transmission synchrotron topograph were calculated for the 3 anti 2 anti 12 and 0 anti 222 reflections based on results from high-resolution X-ray diffractometry. It is confirmed that one of the {01 anti 1 anti 2} m planes is the composition face of the twin and matrix crystals. The formation mechanism of these twins is discussed. (orig.)

  17. Modal Analysis of a Single-Structure Multiaxis MEMS Gyroscope

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Shah

    2016-01-01

    Full Text Available This paper reports on designing a single-structure triaxes MEMS capacitive gyroscope which is capable of measuring the three angular velocities on a single drive. A Z-shaped beam for the support of folded coupling spring has been applied to suppress the unwanted mode and decrease the stress effect at the spring ends. The unique coupling spring has changed the driving motion, due to which slide film damping in the driving mode has been reduced. This reduction can lead to higher performance of the sensor with less requirements on vacuum level which decreases the cost of fabrication. Simulation analysis has been performed in COMSOL Multiphysics and Matlab Simulink to finalize the design for fabrication. After finite element analysis, the driving, x-sensing, z-sensing, and y-sensing are, respectively, found to be 13.30 KHz, 13.40 KHz, 13.47 KHz, and 13.51 KHz.

  18. Protein Data Bank (PDB): The Single Global Macromolecular Structure Archive.

    Science.gov (United States)

    Burley, Stephen K; Berman, Helen M; Kleywegt, Gerard J; Markley, John L; Nakamura, Haruki; Velankar, Sameer

    2017-01-01

    The Protein Data Bank (PDB)--the single global repository of experimentally determined 3D structures of biological macromolecules and their complexes--was established in 1971, becoming the first open-access digital resource in the biological sciences. The PDB archive currently houses ~130,000 entries (May 2017). It is managed by the Worldwide Protein Data Bank organization (wwPDB; wwpdb.org), which includes the RCSB Protein Data Bank (RCSB PDB; rcsb.org), the Protein Data Bank Japan (PDBj; pdbj.org), the Protein Data Bank in Europe (PDBe; pdbe.org), and BioMagResBank (BMRB; www.bmrb.wisc.edu). The four wwPDB partners operate a unified global software system that enforces community-agreed data standards and supports data Deposition, Biocuration, and Validation of ~11,000 new PDB entries annually (deposit.wwpdb.org). The RCSB PDB currently acts as the archive keeper, ensuring disaster recovery of PDB data and coordinating weekly updates. wwPDB partners disseminate the same archival data from multiple FTP sites, while operating complementary websites that provide their own views of PDB data with selected value-added information and links to related data resources. At present, the PDB archives experimental data, associated metadata, and 3D-atomic level structural models derived from three well-established methods: crystallography, nuclear magnetic resonance spectroscopy (NMR), and electron microscopy (3DEM). wwPDB partners are working closely with experts in related experimental areas (small-angle scattering, chemical cross-linking/mass spectrometry, Forster energy resonance transfer or FRET, etc.) to establish a federation of data resources that will support sustainable archiving and validation of 3D structural models and experimental data derived from integrative or hybrid methods.

  19. IMBALANCES' STATISTICAL ESTIMATION OF NATIONAL ECONOMICS ' SECTORAL STRUCTURE

    Directory of Open Access Journals (Sweden)

    T. Trubnik

    2014-04-01

    Full Text Available In article offered diagnostics of violations' tools proportions of sectoral distribution. The indicators system seeks to identify macroeconomic imbalances and adapted to the specific structures by sectoral, reproductive, regional and institutional characteristics. Been developed directions of forming strategy recovery of economic growth. Detected major national economics' sectoral imbalances and provides recommendations for the adjustment of sectoral policies.

  20. Development of a national code of practice for structural masonry ...

    African Journals Online (AJOL)

    The problems and constraints faced by most developing countries, particularly Ghana, in developing codes of practice for structural masonry are highlighted. The steps that must be undertaken through the coordinated efforts of the National Standards Boards, Research Institutions, Universities and Professional Bodies in the ...

  1. Social Structure, Anomie, and National Levels of Homicide.

    Science.gov (United States)

    Schaible, Lonnie M; Altheimer, Irshad

    2016-06-01

    Merton's "Social Structure and Anomie" seeks to explain how "socio-cultural" influences exert "definite pressures" to engage in non-conformity. Despite having a significant influence, few studies have assessed the degree to which Merton's propositions explain cross-national variation in levels of crime. Using data on national levels of homicide, data from the World Values Survey, and other structural controls, the present study assesses the degree to which deinstitutionalization, demoralization, and blocked opportunity interact to explain crime cross-nationally. Results provide a high degree of support for Merton's assertion that societal types characterized by relatively high levels of materialism and/or demoralization or deinstitutionalization suffer from higher levels of homicide. However, there is less support for Merton's assertion that inequality interacts with various societal patterns of means/ends integration in a meaningful way. Findings and implications for the utility of classical anomie as a general macro-level theory are discussed. © The Author(s) 2015.

  2. 75 FR 30842 - Statutorily Mandated Single Source Award Program Name: National Indian Health Board

    Science.gov (United States)

    2010-06-02

    ... consistently provided education and outreach to Tribal leadership regarding the potential impact of Health Care... DEPARTMENT OF HEALTH AND HUMAN SERVICES Indian Health Service Statutorily Mandated Single Source Award Program Name: National Indian Health Board AGENCY: Indian Health Service, HHS. ACTION: Notice of...

  3. Deformation of periodic nanovoid structures in Mg single crystals

    Science.gov (United States)

    Xu, Shuozhi; Su, Yanqing; Zare Chavoshi, Saeed

    2018-01-01

    Large scale molecular dynamics (MD) simulations in Mg single crystal containing periodic cylindrical voids subject to uniaxial tension along the z direction are carried out. Models with different initial void sizes and crystallographic orientations are explored using two interatomic potentials. It is found that (i) a larger initial void always leads to a lower yield stress, in agreement with an analytic prediction; (ii) in the model with x[\\bar{1}100]–y[0001]–z[11\\bar{2}0] orientations, the two potentials predict different types of tension twins and phase transformation; (iii) in the model with x[0001]–y[11\\bar{2}0]–z[\\bar{1}100] orientations, the two potentials identically predict the nucleation of edge dislocations on the prismatic plane, which then glide away from the void, resulting in extrusions at the void surface; in the case of the smallest initial void, these surface extrusions pinch the void into two voids. Besides bringing new physical understanding of the nanovoid structures, our work highlights the variability and uncertainty in MD simulations arising from the interatomic potential, an issue relatively lightly addressed in the literature to date.

  4. Solar cell structure incorporating a novel single crystal silicon material

    Science.gov (United States)

    Pankove, Jacques I.; Wu, Chung P.

    1983-01-01

    A novel hydrogen rich single crystal silicon material having a band gap energy greater than 1.1 eV can be fabricated by forming an amorphous region of graded crystallinity in a body of single crystalline silicon and thereafter contacting the region with atomic hydrogen followed by pulsed laser annealing at a sufficient power and for a sufficient duration to recrystallize the region into single crystal silicon without out-gassing the hydrogen. The new material can be used to fabricate semiconductor devices such as single crystal silicon solar cells with surface window regions having a greater band gap energy than that of single crystal silicon without hydrogen.

  5. Debt, Structural Adjustment and Deforestation: A Cross-National Study

    Directory of Open Access Journals (Sweden)

    John M. Shandra

    2015-08-01

    Full Text Available We present cross-national models that examine the determinants of deforestation from 1990 to 2005 for a sample of sixty-two poor nations. We test dependency theory hypotheses that both debt and structural adjustment affect forests. We find substantial support for this theoretical perspective. The results indicate that both factors increase deforestation. We also find support for world polity theory that international non-governmental organization density decreases deforestation. We conclude with a brief discussion of the findings, policy implications, and possible directions for future research.

  6. 15th National Conference on Nuclear Structure in China

    CERN Document Server

    Wang, Ning; Zhou, Shan-Gui; Nuclear Structure in China 2014; NSC2014

    2016-01-01

    This volume is a collection of the contributions to the 15th National Conference on Nuclear Structure in China (NSC2014), held on October 25-28, 2014 in Guilin, China and hosted by Guangxi Normal University. It provides an important updated resource in the nuclear physics literature for researchers and graduate students studying nuclear structure and related topics. Recent progress made in the study of nuclear spectroscopy of high-spin states, nuclear mass and half-life, nuclear astrophysics, super-heavy nuclei, unstable nuclei, density functional theory, neutron star and symmetry energy, nuclear matter, and nuclear shell model are covered.

  7. Structure and experiences of the Australian National Authority

    International Nuclear Information System (INIS)

    Bett, F.L.

    1989-01-01

    A detailed account is given of the history, structure and functions of the Australian Safeguards Office (ASO). Its nuclear materials accounting and control procedures and its research and development programs are discussed. Australia's physical protection policy and the ASO's role in this field are described. The Australian views on State Systems of Accounting for and Control of Nuclear Materials and the establishment of National Authorities such as the ASO are outlined

  8. Mechanical Properties of a Single Electrospun Fiber and its Structures

    NARCIS (Netherlands)

    Gu, S.; Gu, Shuying; Wu, Qi-Lin; Ren, Jie; Vancso, Gyula J.

    2005-01-01

    A method to measure the Young's modulus of a single electrospun polyacrylonitrile (PAN) fiber is reported. The Young's modulus can be calculated from the force-displacement curves obtained by the bending of a single fiber attached to an atomic force microscopy (AFM) cantilever. It is suggested that

  9. Zero-mode waveguide nanophotonic structures for single molecule characterization

    Science.gov (United States)

    Crouch, Garrison M.; Han, Donghoon; Bohn, Paul W.

    2018-05-01

    Single-molecule characterization has become a crucial research tool in the chemical and life sciences, but limitations, such as limited concentration range, inability to control molecular distributions in space, and intrinsic phenomena, such as photobleaching, present significant challenges. Recent developments in non-classical optics and nanophotonics offer promising routes to mitigating these restrictions, such that even low affinity (K D ~ mM) biomolecular interactions can be studied. Here we introduce and review specific nanophotonic devices used to support single molecule studies. Optical nanostructures, such as zero-mode waveguides (ZMWs), are usually fabricated in thin gold or aluminum films and serve to confine the observation volume of optical microspectroscopy to attoliter to zeptoliter volumes. These simple nanostructures allow individual molecules to be isolated for optical and electrochemical analysis, even when the molecules of interest are present at high concentration (µM–mM) in bulk solution. Arrays of ZMWs may be combined with optical probes such as single molecule fluorescence, single molecule fluorescence resonance energy transfer, and fluorescence correlation spectroscopy for distributed analysis of large numbers of single-molecule reactions or binding events in parallel. Furthermore, ZMWs may be used as multifunctional devices, for example by combining optical and electrochemical functions in a single discrete architecture to achieve electrochemical ZMWs. In this review, we will describe the optical properties, fabrication, and applications of ZMWs for single-molecule studies, as well as the integration of ZMWs into systems for chemical and biochemical analysis.

  10. Comprehensive Wavelengths, Energy Levels, and Hyperfine Structure Parameters of Singly-Ionized Iron-Group Elements

    Science.gov (United States)

    Nave, Gillian

    We propose to measure wavelengths, energy levels, and hyperfine structure parameters of Ni II, Mn II, Sc II and other singly-ionized iron-group elements, covering the wavelength range 80 nm to 5500 nm. We shall use archival data from spectrometers at NIST and Kitt Peak National Observatory for spectra above 140 nm. Additional experimental observations will be taken if needed using Fourier transform spectrometers at NIST. Spectra will be taken using our normal incidence grating spectrograph to provide better sensitivity than the FT spectra and to extend the wavelength range down to 80 nm. We aim to produce a comprehensive description of the spectra of all singly-ionized iron- group elements. The wavelength uncertainty of the strong lines will be better than 1 part in 10^7. For most singly-ionized iron-group elements available laboratory data have uncertainties an order of magnitude larger than astronomical observations over wide spectra ranges. Some of these laboratory measurements date back to the 1960's. Since then, Fourier transform spectroscopy has made significant progress in improving the accuracy and quantity of data in the UV-vis-IR region, but high quality Fourier transform spectra are still needed for Mn II, Ni II and Sc II. Fourier transform spectroscopy has low sensitivity in the VUV region and is limited to wavelengths above 140 nm. Spectra measured with high-resolution grating spectrographs are needed in this region in order to obtain laboratory data of comparable quality to the STIS and COS spectrographs on the Hubble Space Telescope. Currently, such data exist only for Fe II and Cr II. Lines of Sc II, V II, and Mn II show hyperfine structure, but hyperfine structure parameters have been measured for relatively few lines of these elements. Significant errors can occur if hyperfine structure is neglected when abundances are determined from stellar spectra. Measurements of hyperfine structure parameters will be made using Fourier transform spectroscopy

  11. National impacts of the Weatherization Assistance Program in single-family and small multifamily dwellings

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.A.; Berry, L.G.; Balzer, R.A.; Faby, E.

    1993-05-01

    Since 1976, the US Department of Energy (DOE) has operated one of the largest energy conservation programs in the nation -- the low-income Weatherization Assistance Program. The program strives to increase the energy efficiency of dwellings occupied by low-income persons in order to reduce their energy consumption, lower their fuel bills, increase the comfort of their homes, and safeguard their health. It targets vulnerable groups including the elderly, people with disabilities, and families with children. The most recent national evaluation of the impacts of the Program was completed in 1984 based on energy consumption data for households weatherized in 1981. DOE Program regulations and operations have changed substantially since then: new funding sources, management principles, diagnostic procedures, and weatherization technologies have been incorporated. Many of these new features have been studied in isolation or at a local level; however, no recent evaluation has assessed their combined, nationwide impacts to date or their potential for the future. In 1990, DOE initiated such an evaluation. This evaluation is comprised of three ``impact`` studies (the Single-Family Study, High-Density Multifamily Study, and Fuel-Oil Study) and two ``policy`` studies. Altogether, these five studies will provide a comprehensive national assessment of the Weatherization Assistance Program as it existed in the 1989 Program Year (PY 1989). This report presents the results of the first phase of the Single-Family Study. It evaluates the energy savings and cost effectiveness of the Program as it has been applied to the largest portion of its client base -- low-income households that occupy single-family dwellings, mobile homes, and small (2- to 4-unit) multifamily dwellings. It is based upon a representative national sample that covers the full range of conditions under which the program was implemented in PY 1989.

  12. Single crystal growth and X-ray structure analysis of non-peripheral octahexyl phthalocyanine

    Science.gov (United States)

    Ohmori, Masashi; Nakano, Chika; Higashi, Takuya; Miyano, Tetsuya; Tohnai, Norimitsu; Fujii, Akihiko; Ozaki, Masanori

    2016-07-01

    The single-crystal structure of metal-free non-peripheral octahexyl-substituted phthalocyanine (C6PcH2) has been investigated by single-crystal X-ray structure analysis. Two types of C6PcH2 single crystal, bulk and needle crystals, were separately grown by controlling the recrystallization conditions. The structures of the two types of crystal were determined, and were found to be completely different, that is, C6PcH2 exhibits structural polymorphism. It has been clarified that the C6PcH2 microcrystals in thin films used in previously reported electronic devices have the needle structure.

  13. Population structure of Han nationality in Central-Southern China.

    Science.gov (United States)

    Liu, Qiu-Ling; Chen, Ye-Fei; He, Xin; Shi, Yan-Wei; Wu, Wei-Wei; Zhao, Hu; Lu, De-Jian

    2017-07-01

    Knowledge of population structure is very important for forensic genetics. However, the population substructure in Central-Southern China Han nationality has still not been fully described. In this study, we investigated the genetic diversity of 15 forensic autosomal STR loci from 6879 individuals in 12 Han populations subdivided by administrative provinces in Central-Southern China. The statistical analysis of genetic variation showed that genetic differentiation among these populations was very small with a F st value of 0.0009. The Discriminant Analysis of Principal Components (DAPC) showed that there were no obvious population clusters in Central-Southern China Han population. In practice, the population structure effect in Central-Southern China Han population can be negligible in forensic identification and paternity testing. Copyright © 2017. Published by Elsevier B.V.

  14. Structural Design of Two-Cylinder Single Overhead Camshaft

    Science.gov (United States)

    Zhao, Yuxia; Zhang, Kangsheng; Di, Jiejian

    2018-01-01

    Due to the higher performance demand, the camshaft is the key driving part in the engine. Because it is eccentric circular section part, it is very difficult to design and manufacture this kind of axial parts. Take two-cylinder single overhead camshaft for an example, the entire process of camshaft design is analyzed. The practice has proved that the method has simple, flexible and efficient advantages, and it can greatly shorten the design of artificial computing time.

  15. Vaginal Radical Trachelectomy for early stage cervical cancer. Results of the Danish National Single Center Strategy

    DEFF Research Database (Denmark)

    Hauerberg, L; Høgdall, C; Loft, A

    2015-01-01

    OBJECTIVE: To present and evaluate an unselected national single center strategy with fertility preserving trachelectomy in cervical cancer. In 2003 nationwide single-center referral of women for trachelectomies was agreed upon between all Danish departments performing cervical cancer surgery...... with the purpose of increasing volume, to increase surgical safety and facilitate follow-up. METHODS: Prospective data were recorded in the Danish Gynecological Cancer Database of all Vaginal Radical Trachelectomies (VRT) performed in Denmark between 2002 and 2013. Oncologic, fertility and obstetrical outcomes...... of 120 unselected consecutive VRTs were assessed. To obtain complete follow-up about fertility treatment, pregnancy and obstetric outcome the women filled out an electronic questionnaire. Median follow-up: 55.7 months. RESULTS: 85.8% of the patients had stage IB1 disease, 68.3% squamous cell carcinomas...

  16. Understanding the Structural Evolution of Single Conjugated Polymer Chain Conformers

    Directory of Open Access Journals (Sweden)

    Adam J. Wise

    2016-11-01

    Full Text Available Single molecule photoluminescence (PL spectroscopy of conjugated polymers has shed new light on the complex structure–function relationships of these materials. Although extensive work has been carried out using polarization and excitation intensity modulated experiments to elucidate conformation-dependent photophysics, surprisingly little attention has been given to information contained in the PL spectral line shapes. We investigate single molecule PL spectra of the prototypical conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy-1,4-phenylenevinylene] (MEH-PPV which exists in at least two emissive conformers and can only be observed at dilute levels. Using a model based on the well-known “Missing Mode Effect” (MIME, we show that vibronic progression intervals for MEH-PPV conformers can be explained by relative contributions from particular skeletal vibrational modes. Here, observed progression intervals do not match any ground state Raman active vibrational frequency and instead represent a coalescence of multiple modes in the frequency domain. For example, the higher energy emitting “blue” MEH-PPV form exhibits PL maxima at ~18,200 cm−1 with characteristic MIME progression intervals of ~1200–1350 cm−1, whereas the lower energy emitting “red” form peaks at ~17,100 cm−1 with intervals in the range of ~1350–1450 cm−1. The main differences in blue and red MEH-PPV chromophores lie in the intra-chain order, or, planarity of monomers within a chromophore segment. We demonstrate that the Raman-active out-of-plane C–H wag of the MEH-PPV vinylene group (~966 cm−1 has the greatest influence in determining the observed vibronic progression MIME interval. Namely, larger displacements (intensities—indicating lower intra-chain order—lower the effective MIME interval. This simple model provides useful insights into the conformational characteristics of the heterogeneous chromophore landscape without requiring costly and

  17. Improved PLL structures for single-phase grid inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    of the reference signals. This paper presents two improved phase-locked-loop (PLL) methods for single-phase grid connected systems. The investigated PLL methods are based on a transport delay method and an inverse Park transformation method. The improvements in the case of using the delay-based PLL are: non......-frequency dependent and better filtering of the harmonics. For the other investigated PLL method based on inverse Park transformation the improvement consists of better filtering of the harmonics. Experimental results validate the effectiveness of the two proposed methods....

  18. Dynamics Assessment of Advanced Single-Phase PLL Structures

    DEFF Research Database (Denmark)

    Golestan, Saeed; Monfarad, Mohammad; Freijedo, Francisco D.

    2013-01-01

    , and desired performance under frequency-varying and harmonically distorted grid conditions. Despite the wide acceptance and use of these two advanced PLLs, no comprehensive design guidelines to fine-tune their parameters have been reported yet. Through a detailed mathematical analysis it is shown......Recently, several advanced phase locked loop (PLL) techniques have been proposed for single-phase applications. Among these, the Park-PLL, and the second order generalized integrator (SOGI) based PLL are very attractive, owing to their simple digital implementation, low computational burden...

  19. Single crystalline silicon solar cells with rib structure

    Directory of Open Access Journals (Sweden)

    Shuhei Yoshiba

    2017-02-01

    Full Text Available To improve the conversion efficiency of Si solar cells, we have developed a thin Si wafer-based solar cell that uses a rib structure. The open-circuit voltage of a solar cell is known to increase with deceasing wafer thickness if the cell is adequately passivated. However, it is not easy to handle very thin wafers because they are brittle and are subject to warpage. We fabricated a lattice-shaped rib structure on the rear side of a thin Si wafer to improve the wafer’s strength. A silicon nitride film was deposited on the Si wafer surface and patterned to form a mask to fabricate the lattice-shaped rib, and the wafer was then etched using KOH to reduce the thickness of the active area, except for the rib region. Using this structure in a Si heterojunction cell, we demonstrated that a high open-circuit voltage (VOC could be obtained by thinning the wafer without sacrificing its strength. A wafer with thickness of 30 μm was prepared easily using this structure. We then fabricated Si heterojunction solar cells using these rib wafers, and measured their implied VOC as a function of wafer thickness. The measured values were compared with device simulation results, and we found that the measured VOC agrees well with the simulated results. To optimize the rib and cell design, we also performed device simulations using various wafer thicknesses and rib dimensions.

  20. An Investigation of Ni2P Single Crystal Surfaces : Structure, Electronic State and Reactivity

    OpenAIRE

    Yuan, Qiuyi; Ariga, Hiroko; Asakura, Kiyotaka

    2015-01-01

    Ni2P has demonstrated high catalytic activity for hydrodesulfurization and has recently been employed as a catalyst in a variety of other reactions. We have thoroughly reviewed the literature concerning Ni2P single crystal surfaces, with the aim of determining the relationship between surface structure and catalytic properties. Published results to date indicate that Ni2P single crystal surfaces exhibit reconstructed structures, and so the bulk terminated structure may not be stable. We have ...

  1. Reliability in Single, Double and N2R Ring Network Structures

    DEFF Research Database (Denmark)

    Jørgensen, T.; Pedersen, L.; Pedersen, Jens Myrup

    This paper studies the properties of single, double and N2R ring network structures during link errors. The structure of the network infrastructure must be redesigned in order to fulfil the requirements of services using the Internet in the future; hence, N2R structures have been suggested. N2R s...

  2. Conduction Mechanisms and Structure of Ionomeric Single-Ion Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Colby, Ralph H. [Pennsylvania State Univ., University Park, PA (United States); Maranas, Janna K. [Pennsylvania State Univ., University Park, PA (United States); Mueller, Karl T. [Pennsylvania State Univ., University Park, PA (United States); Runt, James [Pennsylvania State Univ., University Park, PA (United States); Winey, Karen I. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2015-03-01

    Our team has designed using DFT (Gaussian) and synthesized low glass transition temperature single-ion conductors that are either polyanions that conduct small cations Li+, Na+, Cs+ or polycations that conduct small anions F-, OH-, Br-. We utilize a wide range of complimentary experimental materials characterization tools to understand ion transport; differential scanning calorimetry, dielectric relaxation spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, linear viscoelasticity, X-ray scattering and molecular dynamics simulations. The glass transition temperature Tg needs to be as low as possible to facilitate ion transport, so the nonionic parts of the polymer need to be polar, flexible and have strong solvation interactions with the ions. The lowest Tg we have managed for polyanions conducting Li+ is -60 °C. In contrast, polysiloxanes with PEO side chains and tetrabutylphosphonium cationic side groups have Tg ≈ -75 °C that barely increases with ion content, as anticipated by DFT. A survey of all polyanions in the literature suggests that Tg < -80 °C is needed to achieve the 10-4 S/cm conductivity needed for battery separators.

  3. Modelling Single Tree Structure with Terrestrial Laser Scanner

    Science.gov (United States)

    Yurtseven, H.; Akgül, M.; Gülci, S.

    2017-11-01

    Recent technological developments, which has reliable accuracy and quality for all engineering works, such as remote sensing tools have wide range use in forestry applications. Last decade, sustainable use and management opportunities of forest resources are favorite topics. Thus, precision of obtained data plays an important role in evaluation of current status of forests' value. The use of aerial and terrestrial laser technology has more reliable and effective models to advance the appropriate natural resource management. This study investigates the use of terrestrial laser scanner (TLS) technology in forestry, and also the methodological data processing stages for tree volume extraction is explained. Z+F Imager 5010C TLS system was used for measure single tree information such as tree height, diameter of breast height, branch volume and canopy closure. In this context more detailed and accurate data can be obtained than conventional inventory sampling in forestry by using TLS systems. However the accuracy of obtained data is up to the experiences of TLS operator in the field. Number of scan stations and its positions are other important factors to reduce noise effect and accurate 3D modelling. The results indicated that the use of point cloud data to extract tree information for forestry applications are promising methodology for precision forestry.

  4. National Atlas of Arctic: structure and creation approaches

    Directory of Open Access Journals (Sweden)

    N. S. Kasimov

    2015-01-01

    Full Text Available On the instructions of President and Government of the Russian Federation, works for development of National Atlas of Arctic are started in the country. In this article the authors present their ideas from viewpoint of geographers who are well experienced in the field of cartographic works. A structure of future Atlas and lines of approaches to its development are proposed. The totality of experiences of preparation of other geographical atlases in both, the USSR and Russia, as well as the latest achievements of cartography, aerospace sources and GIS-technologies are recommended to be used. The National Atlas of Arctic is understood as a collection of knowledge of spatial-temporal information about geographical, ecological, economic, historical-ethnographic, cultural and social features of the Arctic. This cartographic model of the territory is designed for using in a wide range of scientific, managing, economic, defensive and social activities. A hard copy of the atlas is intended to be used as scientific-reference publication while its electronic version will make it possible to renovate its content and to improve it by means of actualization according to various directions of its practical use 16 sections proposed in a draft of the Atlas content are as follows: introductory, geological structure, relief, mineral resources, environment evolution, climate, land waters, seas, seashores, snow cover, glaciers, permafrost, soils, flora and fauna, state of the environment and the Nature protection, population, economics, and prospects for future. The popular-scientific edition of the Atlas is intended for use by wide circle of readers and also as a textbook for all levels of education. Presentation of material in the Atlas should combine a high scientific level and accessible language. In a popular form it will clarify traditions of careful treatment to the Nature and the nature-protective ethics of religious confessions of local people

  5. Myth in the structure of national consciousness | Gizatova | Journal ...

    African Journals Online (AJOL)

    ... multiethnic state, the problem of scientific definition of nations, ethnic groups, national and ethnic consciousness has a special practical significance. In Russia and the post-Soviet space, the activation of mythological thinking has its own specifics. Keywords: Nations, Ethnicity, National consciousness, Myth, Globalization ...

  6. Differences in gray matter structure correlated to nationalism and patriotism

    OpenAIRE

    Takeuchi, Hikaru; Taki, Yasuyuki; Sekiguchi, Atsushi; Nouchi, Rui; Kotozaki, Yuka; Nakagawa, Seishu; Miyauchi, Carlos Makoto; Iizuka, Kunio; Yokoyama, Ryoichi; Shinada, Takamitsu; Yamamoto, Yuki; Hanawa, Sugiko; Araki, Tsuyoshi; Hashizume, Hiroshi; Kunitoki, Keiko

    2016-01-01

    Nationalism and patriotism both entail positive evaluations of one?s nation. However, the former inherently involves derogation of other nations, whereas the latter is independent of comparisons with other nations. We used voxel-based morphometry and psychological measures and determined nationalism and patriotism?s association with gray matter density (rGMD) and their cognitive nature in healthy individuals (433 men and 344 women; age, 20.7???1.9 years) using whole-brain multiple regression ...

  7. Single cell Hi-C reveals cell-to-cell variability in chromosome structure

    Science.gov (United States)

    Schoenfelder, Stefan; Yaffe, Eitan; Dean, Wendy; Laue, Ernest D.; Tanay, Amos; Fraser, Peter

    2013-01-01

    Large-scale chromosome structure and spatial nuclear arrangement have been linked to control of gene expression and DNA replication and repair. Genomic techniques based on chromosome conformation capture assess contacts for millions of loci simultaneously, but do so by averaging chromosome conformations from millions of nuclei. Here we introduce single cell Hi-C, combined with genome-wide statistical analysis and structural modeling of single copy X chromosomes, to show that individual chromosomes maintain domain organisation at the megabase scale, but show variable cell-to-cell chromosome territory structures at larger scales. Despite this structural stochasticity, localisation of active gene domains to boundaries of territories is a hallmark of chromosomal conformation. Single cell Hi-C data bridge current gaps between genomics and microscopy studies of chromosomes, demonstrating how modular organisation underlies dynamic chromosome structure, and how this structure is probabilistically linked with genome activity patterns. PMID:24067610

  8. Single crystal particles of a mesoporous mixed transition metal oxide with a wormhole structure.

    Science.gov (United States)

    Lee, B; Lu, D; Kondo, J N; Domen, K

    2001-10-21

    A new type of mesoporous mixed transition metal oxide of Nb and Ta (NbTa-TIT-1) has been prepared through a two-step calcination, which consists of single crystal particles with wormhole mesoporous structure.

  9. Use of Minimal Lexical Conceptual Structures for Single-Document Summarization

    National Research Council Canada - National Science Library

    Dorr, Bonnie J; Habash, Nizar Y; Monz, Christof; Schwartz, Richard

    2004-01-01

    This reports provides an overview of the findings and software that have evolved from the Use of Minimal Lexical Conceptual Structures for Single-Document Summarization project over the last six months...

  10. Changing epidemiology of AA amyloidosis: clinical observations over 25 years at a single national referral centre.

    Science.gov (United States)

    Lane, Thirusha; Pinney, Jennifer H; Gilbertson, Janet A; Hutt, David F; Rowczenio, Dorota M; Mahmood, Shameem; Sachchithanantham, Sajitha; Fontana, Marianna; Youngstein, Taryn; Quarta, Candida C; Wechalekar, Ashutosh D; Gillmore, Julian D; Hawkins, Philip N; Lachmann, Helen J

    2017-09-01

    Systemic AA amyloidosis is a serious complication of chronic inflammation; however, there are relatively few published data on its incidence. We investigated the changing epidemiology of AA amyloidosis over a 25-year period at a single national referral centre. We conducted a retrospective study of all patients diagnosed with AA amyloidosis who had attended the centre between 1990 and 2014 inclusive. Six hundred and twenty-five patients were studied in three cohorts: C1: 1990-1997; C2: 1998-2006; C3: 2007-2014. Mean age at presentation increased from 46 in C1 to 56 in C3 (p AA amyloidosis over a quarter of a century, reflecting advances in therapeutics and overall management of complex chronic disease in an ageing population. AA amyloidosis of uncertain aetiology presents an emerging major problem. Newer techniques such as next-generation sequencing may aid diagnosis and effective treatment, thereby improving overall survival.

  11. Reversible Single-Crystal-to-Single-Crystal Structural Transformation in a Mixed-Ligand 2D Layered Metal-Organic Framework: Structural Characterization and Sorption Study

    Directory of Open Access Journals (Sweden)

    Chih-Chieh Wang

    2017-12-01

    Full Text Available A 3D supramolecular network, [Cd(bipy(C4O4(H2O2]·3H2O (1 (bipy = 4,4′-bipyridine and C4O42− = dianion of H2C4O4, constructed by mixed-ligand two-dimensional (2D metal-organic frameworks (MOFs has been reported and structurally determined by the single-crystal X-ray diffraction method and characterized by other physicochemical methods. In 1, the C4O42− and bipy both act as bridging ligands connecting the Cd(II ions to form a 2D layered MOF, which are then extended to a 3D supramolecular network via the mutually parallel and interpenetrating arrangements among the 2D-layered MOFs. Compound 1 shows a two-step dehydration process with weight losses of 11.0% and 7.3%, corresponding to the weight-loss of three guest and two coordinated water molecules, respectively, and exhibits an interesting reversible single-crystal-to-single-crystal (SCSC structural transformation upon de-hydration and re-hydration for guest water molecules. The SCSC structural transformation have been demonstrated and monitored by single-crystal and X-ray powder diffraction, and thermogravimetic analysis studies.

  12. Recent progress on the structure separation of single-wall carbon nanotubes

    Science.gov (United States)

    Cui, Jiaming; Yang, Dehua; Zeng, Xiang; Zhou, Naigen; Liu, Huaping

    2017-11-01

    The mass production of single-structure, single-wall carbon nanotubes (SWCNTs) with identical properties is critical for their basic research and technical applications in the fields of electronics, optics and optoelectronics. Great efforts have been made to control the structures of SWCNTs since their discovery. Recently, the structure separation of SWCNTs has been making great progress. Various solution-sorting methods have been developed to achieve not only the separation of metallic and semiconducting species, but also the sorting of distinct (n, m) single-chirality species and even their enantiomers. This progress would dramatically accelerate the application of SWCNTs in the next-generation electronic devices. Here, we review the recent progress in the structure sorting of SWCNTs and outline the challenges and prospects of the structure separation of SWCNTs.

  13. Authoritative knowledge and single women's unintentional pregnancies, abortions, adoption, and single motherhood: social stigma and structural violence.

    Science.gov (United States)

    Ellison, Marcia A

    2003-09-01

    This article explores the sources of authoritative knowledge that shaped single, white, middle-class women's unintentional pregnancies and child-bearing decisions throughout five reproductive eras. Women who terminated a pregnancy were most influenced by their own personal needs and circumstances. birth mothers' decisions were based on external sources of knowledge, such as their mothers, social workers, and social pressures. In contrast, single mothers based their decision on instincts and their religious or moral beliefs. Reproductive policies further constrained and significantly shaped women's experiences. The social stigma associated with these forms of stratified maternity suggests that categorizing pregnant women by their marital status, or births as out-of-wedlock, reproduces the structural violence implicit to normative models of female sexuality and maternity. This mixed-method study included focus groups to determine the kinds of knowledge women considered authoritative, a mailed survey to quantify these identified sources, and one-on-one interviews to explore outcomes in depth.

  14. Studies of G-quadruplex DNA structures at the single molecule level

    DEFF Research Database (Denmark)

    Kragh, Sofie Louise

    2015-01-01

    Folding of G-quaduplex structures adopted by the human telomeric repeat is here studied by single molecule FRET microscopy. This method allows for the investigation of G-quadruplex structures and their conformational dynamic. Telomeres are located at the ends of our chromosomes and end in a single...... with human telomeric repeat adopt several different G-quadruplex conformations in the presence of K+ ions. G-quadruplexes inhibit telomerase activity and are therefore potential targets for anti-cancer drugs, which can be small molecule ligands capable of stabilizing G-quadruplex structures. Understanding...... range. FRET spectroscopy can be performed on an ensemble of molecules, or on the single molecule level. In single molecule FRET experiments it is possible to follow the behaviour in time for each molecule independently, allowing insight into both dynamically and statistically heterogeneous molecular...

  15. Single-molecule FRET reveals structural heterogeneity of SDS-bound alpha-synuclein

    NARCIS (Netherlands)

    Veldhuis, Gertjan; Segers-Nolten, Ine; Ferlemann, Eva; Subramaniam, Vinod

    2009-01-01

    SDS-concentration-dependent alpha-synuclein structure: Upon interaction with SDS, alpha Syn folds into a structure with two antiparallel alpha-helices. We show from single-molecule FRET that alpha Synn adopts this conformation in an all-or-none fashion below the SDS critical micelle concentration.

  16. LiDAR-derived Vegetation Canopy Structure, Great Smoky Mountains National Park, 2011

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset provides multiple-return LiDAR-derived vegetation canopy structure at 30-meter spatial resolution for the Great Smoky Mountains National Park (GSMNP)....

  17. Social-structural indices and between-nation differences in HIV prevalence

    OpenAIRE

    Tan, Judy Y; Earnshaw, Valerie A; Pratto, Felicia; Rosenthal, Lisa; Kalichman, Seth

    2014-01-01

    Research emphasises the role that social structures play in shaping national HIV prevalence. This study examined how social, economic, and political contexts that may represent the confluence of individual capabilities and environmental affordances or constraints are associated with national HIV prevalence. Based on social-ecological perspectives, we examined social-structural dimensions in relation to national HIV prevalence. The study identified six publicly available nation-level social, p...

  18. Understanding nanocellulose chirality and structure-properties relationship at the single fibril level

    Science.gov (United States)

    Usov, Ivan; Nyström, Gustav; Adamcik, Jozef; Handschin, Stephan; Schütz, Christina; Fall, Andreas; Bergström, Lennart; Mezzenga, Raffaele

    2015-06-01

    Nanocellulose fibrils are ubiquitous in nature and nanotechnologies but their mesoscopic structural assembly is not yet fully understood. Here we study the structural features of rod-like cellulose nanoparticles on a single particle level, by applying statistical polymer physics concepts on electron and atomic force microscopy images, and we assess their physical properties via quantitative nanomechanical mapping. We show evidence of right-handed chirality, observed on both bundles and on single fibrils. Statistical analysis of contours from microscopy images shows a non-Gaussian kink angle distribution. This is inconsistent with a structure consisting of alternating amorphous and crystalline domains along the contour and supports process-induced kink formation. The intrinsic mechanical properties of nanocellulose are extracted from nanoindentation and persistence length method for transversal and longitudinal directions, respectively. The structural analysis is pushed to the level of single cellulose polymer chains, and their smallest associated unit with a proposed 2 × 2 chain-packing arrangement.

  19. Characterization of strained InGaAs single quantum well structures by ion beam methods

    International Nuclear Information System (INIS)

    Yu, K.M.; Chan, K.T.

    1990-01-01

    We have investigated strained InGaAs single quantum well structures using MeV ion beam methods. The structural properties of these structures, including composition and well size, have been studied. It has been found that the composition obtained by Rutherford backscattering spectrometry and particle-induced x-ray emission techniques agrees very well with that obtained by the ion channeling method

  20. The Army's Distribution of Labor: New Force Structure and Missions for the Army National Guard

    National Research Council Canada - National Science Library

    Roberson, Melvin

    1997-01-01

    This Strategy Research Project recommends a new Army National Guard (ARNG) force structure which will successfully accomplish current missions and serve the Total Army's requirements for the future...

  1. Structure of sodium above 100 GPa by single-crystal x-ray diffraction.

    Science.gov (United States)

    McMahon, M I; Gregoryanz, E; Lundegaard, L F; Loa, I; Guillaume, C; Nelmes, R J; Kleppe, A K; Amboage, M; Wilhelm, H; Jephcoat, A P

    2007-10-30

    At pressures above a megabar (100 GPa), sodium crystallizes in a number of complex crystal structures with unusually low melting temperatures, reaching as low as 300 K at 118 GPa. We have utilized this unique behavior at extreme pressures to grow a single crystal of sodium at 108 GPa, and have investigated the complex crystal structure at this pressure using high-intensity x-rays from the new Diamond synchrotron source, in combination with a pressure cell with wide angular apertures. We confirm that, at 108 GPa, sodium is isostructural with the cI16 phase of lithium, and we have refined the full crystal structure of this phase. The results demonstrate the extension of single-crystal structure refinement beyond 100 GPa and raise the prospect of successfully determining the structures of yet more complex phases reported in sodium and other elements at extreme pressures.

  2. CRED Fagatele Bay National Marine Sanctuary Bathymetric Position Index Habitat Structures 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetric Position Index (BPI) Structures are derived from derivatives of Simrad EM-3000 multibeam bathymetry (1 m and 3 m resolution). BPI structures are...

  3. Epitaxial layers of 2122 BCSCO superconductor thin films having single crystalline structure

    Science.gov (United States)

    Pandey, Raghvendra K. (Inventor); Raina, Kanwal K. (Inventor); Solayappan, Narayanan (Inventor)

    1995-01-01

    A substantially single phase, single crystalline, highly epitaxial film of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor which has a T.sub.c (zero resistance) of 83K is provided on a lattice-matched substrate with no intergrowth. This film is produced by a Liquid Phase Epitaxy method which includes the steps of forming a dilute supercooled molten solution of a single phase superconducting mixture of oxides of Bi, Ca, Sr, and Cu having an atomic ratio of about 2:1:2:2 in a nonreactive flux such as KCl, introducing the substrate, e.g., NdGaO.sub.3, into the molten solution at 850.degree. C., cooling the solution from 850.degree. C. to 830.degree. C. to grow the film and rapidly cooling the substrate to room temperature to maintain the desired single phase, single crystalline film structure.

  4. Morphology and atomic-scale structure of single-layer WS2 nanoclusters.

    Science.gov (United States)

    Füchtbauer, Henrik G; Tuxen, Anders K; Moses, Poul G; Topsøe, Henrik; Besenbacher, Flemming; Lauritsen, Jeppe V

    2013-10-14

    Two-dimensional sheets of transition metal (Mo and W) sulfides are attracting strong attention due to the unique electronic and optical properties associated with the material in its single-layer form. The single-layer MoS2 and WS2 are already in widespread commercial use in catalytic applications as both hydrotreating and hydrocracking catalysts. Consequently, characterization of the morphology and atomic structure of such particles is of utmost importance for the understanding of the catalytic active phase. However, in comparison with the related MoS2 system only little is known about the fundamental properties of single-layer WS2 (tungstenite). Here, we use an interplay of atom-resolved Scanning Tunneling Microscopy (STM) studies of Au(111)-supported WS2 nanoparticles and calculated edge structures using Density Functional Theory (DFT) to reveal the equilibrium morphology and prevalent edge structures of single-layer WS2. The STM results reveal that the single layer S-W-S sheets adopt a triangular equilibrium shape under the sulfiding conditions of the synthesis, with fully sulfided edges. The predominant edge structures are determined to be the (101[combining macron]0) W-edge, but for the smallest nanoclusters also the (1[combining macron]010) S-edges become important. DFT calculations are used to construct phase diagrams of the WS2 edges, and describe their sulfur and hydrogen coordination under different conditions, and in this way shed light on the catalytic role of WS2 edges.

  5. Synthesis and Single Crystal Structures of Substituted-1,3-Selenazol-2-amines

    Directory of Open Access Journals (Sweden)

    Guoxiong Hua

    2016-12-01

    Full Text Available The synthesis and X-ray single crystal structures of a series of new 4-substituted-1,3-selenazol-2-amines is reported. The efficient preparation of these compounds was carried out by two-component cyclization of the selenoureas with equimolar amounts of α-haloketones. The selenoureas were obtained from the reaction of Woollins’ reagent with cyanamides, followed by hydrolysis with water. All new compounds have been characterized by IR spectroscopy, multi-NMR (1H, 13C, 77Se spectroscopy, accurate mass measurement and single crystal X-ray structure analysis.

  6. The electronic fine structure of 4-nitrophenyl functionalized single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Chakraborty, Amit K; Coleman, Karl S; Dhanak, Vinod R

    2009-01-01

    Controlling the electronic structure of carbon nanotubes (CNTs) is of great importance to various CNT based applications. Herein the electronic fine structure of single-walled carbon nanotube films modified with 4-nitrophenyl groups, produced following reaction with 4-nitrobenzenediazonium tetrafluoroborate, was investigated for the first time. Various techniques such as x-ray and ultra-violet photoelectron spectroscopy, and near edge x-ray absorption fine structure studies were used to explore the electronic structure, and the results were compared with the measured electrical resistances. A reduction in number of the π electronic states in the valence band consistent with the increased resistance of the functionalized nanotube films was observed.

  7. 78 FR 27240 - Announcing the Award of a New Single-Source Award to the National Council on Family Violence in...

    Science.gov (United States)

    2013-05-09

    ....095] Announcing the Award of a New Single-Source Award to the National Council on Family Violence in... single-source cooperative agreement to the National Council on Family Violence to support the National Domestic Violence Hotline (Hotline). SUMMARY: The Administration for Children and Families (ACF...

  8. Single-particle electron microscopy in the study of membrane protein structure.

    Science.gov (United States)

    De Zorzi, Rita; Mi, Wei; Liao, Maofu; Walz, Thomas

    2016-02-01

    Single-particle electron microscopy (EM) provides the great advantage that protein structure can be studied without the need to grow crystals. However, due to technical limitations, this approach played only a minor role in the study of membrane protein structure. This situation has recently changed dramatically with the introduction of direct electron detection device cameras, which allow images of unprecedented quality to be recorded, also making software algorithms, such as three-dimensional classification and structure refinement, much more powerful. The enhanced potential of single-particle EM was impressively demonstrated by delivering the first long-sought atomic model of a member of the biomedically important transient receptor potential channel family. Structures of several more membrane proteins followed in short order. This review recounts the history of single-particle EM in the study of membrane proteins, describes the technical advances that now allow this approach to generate atomic models of membrane proteins and provides a brief overview of some of the membrane protein structures that have been studied by single-particle EM to date. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Structural Covariates of Homicide Rates : A European City Cross-National Comparative Analysis

    NARCIS (Netherlands)

    McCall, Patricia L.; Nieuwbeerta, Paul

    2007-01-01

    Most previous empirical comparative studies of homicide examine homicide rates across nations or subnational units within a single country. This study is the first in which a European cross-national city comparison is made. The article aims to provide insight into the extent that the homicide rates

  10. The acute spectral structure of single-domain YBa2Cu3O6.9

    International Nuclear Information System (INIS)

    Tobin, J.G.; Solal, F.R.; Fluss, J.M.; Olson, C.G.; Gu, C.; Liu, J.Z.

    1991-01-01

    Extraordinarily sharp spectral features at binding energies near 1eV have been observed in the photoemission spectra of untwinned, single crystal YBa 2 Cu 3 O 6.9 . This is the first observation of such distinctive electronic structure away from the near-Fermi Energy regime, It suggests that the entire valence band electronic structure, not merely the Fermiology, may provide insight into the nature of high temperature superconducting cuprates. 10 refs., 5 figs

  11. Protein secondary structure prediction for a single-sequence using hidden semi-Markov models

    Directory of Open Access Journals (Sweden)

    Borodovsky Mark

    2006-03-01

    Full Text Available Abstract Background The accuracy of protein secondary structure prediction has been improving steadily towards the 88% estimated theoretical limit. There are two types of prediction algorithms: Single-sequence prediction algorithms imply that information about other (homologous proteins is not available, while algorithms of the second type imply that information about homologous proteins is available, and use it intensively. The single-sequence algorithms could make an important contribution to studies of proteins with no detected homologs, however the accuracy of protein secondary structure prediction from a single-sequence is not as high as when the additional evolutionary information is present. Results In this paper, we further refine and extend the hidden semi-Markov model (HSMM initially considered in the BSPSS algorithm. We introduce an improved residue dependency model by considering the patterns of statistically significant amino acid correlation at structural segment borders. We also derive models that specialize on different sections of the dependency structure and incorporate them into HSMM. In addition, we implement an iterative training method to refine estimates of HSMM parameters. The three-state-per-residue accuracy and other accuracy measures of the new method, IPSSP, are shown to be comparable or better than ones for BSPSS as well as for PSIPRED, tested under the single-sequence condition. Conclusions We have shown that new dependency models and training methods bring further improvements to single-sequence protein secondary structure prediction. The results are obtained under cross-validation conditions using a dataset with no pair of sequences having significant sequence similarity. As new sequences are added to the database it is possible to augment the dependency structure and obtain even higher accuracy. Current and future advances should contribute to the improvement of function prediction for orphan proteins inscrutable

  12. Exploring Electronic Structure and Order in Polymers via Single-Particle Microresonator Spectroscopy.

    Science.gov (United States)

    Horak, Erik H; Rea, Morgan T; Heylman, Kevin D; Gelbwaser-Klimovsky, David; Saikin, Semion K; Thompson, Blaise J; Kohler, Daniel D; Knapper, Kassandra A; Wei, Wei; Pan, Feng; Gopalan, Padma; Wright, John C; Aspuru-Guzik, Alán; Goldsmith, Randall H

    2018-02-08

    PSS, a transparent electrically conductive polymer, finds widespread use in electronic devices. While empirical efforts have increased conductivity, a detailed understanding of the coupled electronic and morphological landscapes in PEDOT:PSS has lagged due to substantial structural heterogeneity on multiple length-scales. We use an optical microresonator-based absorption spectrometer to perform single-particle measurements, providing a bottom-up examination of electronic structure and morphology ranging from single PEDOT:PSS polymers to nascent films. Using single-particle spectroscopy with complementary theoretical calculations and ultrafast spectroscopy, we demonstrate that PEDOT:PSS displays bulk-like optical response even in single polymers. We find highly ordered PEDOT assemblies with long-range ordering mediated by the insulating PSS matrix and reveal a preferential surface orientation of PEDOT nanocrystallites absent in bulk films with implications for interfacial electronic communication. Our single-particle perspective provides a unique window into the microscopic structure and electronic properties of PEDOT:PSS.

  13. Protein structural model selection by combining consensus and single scoring methods.

    Directory of Open Access Journals (Sweden)

    Zhiquan He

    Full Text Available Quality assessment (QA for predicted protein structural models is an important and challenging research problem in protein structure prediction. Consensus Global Distance Test (CGDT methods assess each decoy (predicted structural model based on its structural similarity to all others in a decoy set and has been proved to work well when good decoys are in a majority cluster. Scoring functions evaluate each single decoy based on its structural properties. Both methods have their merits and limitations. In this paper, we present a novel method called PWCom, which consists of two neural networks sequentially to combine CGDT and single model scoring methods such as RW, DDFire and OPUS-Ca. Specifically, for every pair of decoys, the difference of the corresponding feature vectors is input to the first neural network which enables one to predict whether the decoy-pair are significantly different in terms of their GDT scores to the native. If yes, the second neural network is used to decide which one of the two is closer to the native structure. The quality score for each decoy in the pool is based on the number of winning times during the pairwise comparisons. Test results on three benchmark datasets from different model generation methods showed that PWCom significantly improves over consensus GDT and single scoring methods. The QA server (MUFOLD-Server applying this method in CASP 10 QA category was ranked the second place in terms of Pearson and Spearman correlation performance.

  14. Gallium arsenide single crystal solar cell structure and method of making

    Science.gov (United States)

    Stirn, Richard J. (Inventor)

    1983-01-01

    A production method and structure for a thin-film GaAs crystal for a solar cell on a single-crystal silicon substrate (10) comprising the steps of growing a single-crystal interlayer (12) of material having a closer match in lattice and thermal expansion with single-crystal GaAs than the single-crystal silicon of the substrate, and epitaxially growing a single-crystal film (14) on the interlayer. The material of the interlayer may be germanium or graded germanium-silicon alloy, with low germanium content at the silicon substrate interface, and high germanium content at the upper surface. The surface of the interface layer (12) is annealed for recrystallization by a pulsed beam of energy (laser or electron) prior to growing the interlayer. The solar cell structure may be grown as a single-crystal n.sup.+ /p shallow homojunction film or as a p/n or n/p junction film. A Ga(Al)AS heteroface film may be grown over the GaAs film.

  15. Single-molecule, structural and functional studies of Listeria monocytogenes Ca2+-ATPase

    DEFF Research Database (Denmark)

    Dyla, Mateusz

    -ion transport (e.g. H+ for Ca2+-ATPases). P-type ATPases undergo major conformational changes during their functional cycle, as has been learned from a wealth of atomic-resolution X-ray crystallographic structures (4). In this work, single-molecule, structural and functional studies were employed to investigate...... the dynamics and mechanism of the transport cycle of P-type ATPase at a single molecule level. A representative P-type ATPase, the Listeria monocytogenes Ca2+-ATPase (LMCA1) was engineered and characterized to facilitate smFRET studies. Pairs of cysteines were introduced and reacted with maleimide derivatives...... transitions to the E2 state triggered by ATP binding and phosphorylation were very brief, and could only be characterized in a dephosphorylation-deficient LMCA1 mutant. Owing to a spontaneous dephosphorylation of this mutant, full transport cycles at a single-molecule resolution were observed for the first...

  16. Single Nanostructure Electrochemical Devices for Studying Electronic Properties and Structural Changes in Lithiated Si Nanowires

    KAUST Repository

    McDowell, Matthew T.

    2011-07-19

    Nanostructured Si is a promising anode material for the next generation of Li-ion batteries, but few studies have focused on the electrical properties of the Li-Si alloy phase, which are important for determining power capabilities and ensuring sufficient electrical conduction in the electrode structure. Here, we demonstrate an electrochemical device framework suitable for testing the electrical properties of single Si nanowires (NWs) at different lithiation states and correlating these properties with structural changes via transmission electron microscopy (TEM). We fi nd that single Si NWs usually exhibit Ohmic I - V response in the lithiated state, with conductivities two to three orders of magnitude higher than in the delithiated state. After a number of sequential lithiation/delithiation cycles, the single NWs show similar conductivity after each lithiation step but show large variations in conductivity in the delithiated state. Finally, devices with groups of NWs in physical contact were fabricated, and structural changes in the NWs were observed after lithiation to investigate how the electrical resistance of NW junctions and the NWs themselves affect the lithiation behavior. The results suggest that electrical resistance of NW junctions can limit lithiation. Overall, this study shows the importance of investigating the electronic properties of individual components of a battery electrode (single nanostructures in this case) along with studying the nature of interactions within a collection of these component structures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Integrated view of genome structure and sequence of a single DNA molecule in a nanofluidic device

    DEFF Research Database (Denmark)

    Marie, Rodolphe; Pedersen, Jonas Nyvold; L. V. Bauer, David

    2013-01-01

    We show how a bird’s-eye view of genomic structure can be obtained at ∼1-kb resolution from long (∼2 Mb) DNA molecules extracted from whole chromosomes in a nanofluidic laboratoryon-a-chip. We use an improved single-molecule denaturation mapping approach to detect repetitive elements and known...

  18. Synthesis and Single Crystal X-Ray Structure Determination of 3,3',5 ...

    African Journals Online (AJOL)

    Single crystal structure determination at 100 K revealed needle-like crystals in an orthorhombic crystal system. The asymmetric unit of the cell consists of an isolated chloride ion, one half of a tetrahedral [MnCl4]2- anion, a [H2Me4bpz]2+ dication and one half of a molecule of water. Keywords: Crystal Engineering, Hydrogen ...

  19. Structure, single-particle and many-particle coefficients of Lennard ...

    Indian Academy of Sciences (India)

    We investigate the effects of temperature and density on the single-particle and many-particle coefficients as well as on the structures of homogenous systems in which the particles are assumed to interact via a continuous soft sphere potential in the microcanonical ensemble. The pair distribution function and therefore the ...

  20. Single Event Testing on Complex Devices: Test Like You Fly versus Test-Specific Design Structures

    Science.gov (United States)

    Berg, Melanie; LaBel, Kenneth A.

    2014-01-01

    We present a framework for evaluating complex digital systems targeted for harsh radiation environments such as space. Focus is limited to analyzing the single event upset (SEU) susceptibility of designs implemented inside Field Programmable Gate Array (FPGA) devices. Tradeoffs are provided between application-specific versus test-specific test structures.

  1. Unraveling the structure of DNA during overstretching by using multicolor, single-molecule fluorescence imaging.

    NARCIS (Netherlands)

    van Mameren, J.; Gross, P.; Farge, G.; Hooijman, P.; Modesti, M.; Falkenberg, M.; Wuite, G.J.L.; Peterman, E.J.G.

    2009-01-01

    Single-molecule manipulation studies have revealed that double-stranded DNA undergoes a structural transition when subjected to tension. At forces that depend on the attachment geometry of the DNA (65 pN or 110 pN), it elongates ≈1.7-fold and its elastic properties change dramatically. The nature of

  2. Creep and Dislocation Structure in Copper Single Crystals Compressed in Directions [010], [110] and [111

    Czech Academy of Sciences Publication Activity Database

    Orlová, Alena

    2001-01-01

    Roč. 92, č. 1 (2001), s. 76-81 ISSN 0044-3093 R&D Projects: GA ČR GA106/98/1369 Institutional research plan: CEZ:AV0Z2041904 Keywords : dislocation structure * single crystals of copper * creep Subject RIV: JG - Metallurgy Impact factor: 0.768, year: 2001

  3. A structured record to implement the national Guidelines for ...

    African Journals Online (AJOL)

    Background. Guidelines to improve standards of care for hypertension and diabetes were disseminated by the National Department of Health in 1996 but have generally not been implemented by health professionals in local primary care. A strategy for the adoption and implementation of the Guidelines was developed in ...

  4. Attendance structure and economic impact of the National Road Festival

    Science.gov (United States)

    Charles H. Strauss; Bruce E. Lord

    2001-01-01

    The National Road Festival is a four-day event scheduled in mid-May along a 90-mile section of U.S. Route 40 within the southwestern Pennsylvania counties of Washington, Fayette, and Somerset. This 26-year tradition commemorates America's first federally funded highway and includes over 30 recreational sites and community attractions. The Festival provides a...

  5. Fracture behavior of single-structure fiber-reinforced composite restorations.

    Science.gov (United States)

    Nagata, Kohji; Garoushi, Sufyan K; Vallittu, Pekka K; Wakabayashi, Noriyuki; Takahashi, Hidekazu; Lassila, Lippo V J

    2016-12-01

    Objective: The applications of single-structure fiber-reinforced composite (FRC) in restorative dentistry have not been well reported. This study aimed to clarify the static mechanical properties of anterior crown restorations prepared using two types of single-structure FRC. Materials and methods : An experimental crown restoration was designed for an upper anterior incisor. The restorations were made from IPS Empress CAD for CEREC (Emp), IPS e.max ® CAD (eMx), experimental single-structure all-FRC (a-FRC), Filtek™ Supreme XTE (XTE), and commercially available single-structure short-FRC (everX Posterior™) ( n = 8 for each material) (s-FRC). The a-FRC restorations were prepared from an experimental FRC blank using a computer-aided design and manufacturing (CAD/CAM) device. A fracture test was performed to assess the fracture load, toughness, and failure mode. The fracture loads were vertically applied on the restorations. The surface micromorphology of the FRC restorations was observed by scanning electron microscopy (SEM). The data were analyzed by analysis of variance ( p = .05) followed by Tukey's test. Results : s-FRC showed the highest mean fracture load (1145.0 ± 89.6 N) and toughness (26.2 ± 5.8 Ncm) among all the groups tested. With regard to the micromorphology of the prosthetic surface, local crushing of the fiberglass was observed in s-FRC, whereas chopped fiberglass was observed in a-FRC. Conclusions : The restorations made of short-FRC showed a higher load-bearing capacity than those made of the experimental all-FRC blanks for CAD/CAM. The brittle-like fractures were exhibited in the recent dental esthetic materials, while local crushing fractures were shown for single-structure FRC restorations.

  6. Thin films of metal oxides on metal single crystals: Structure and growth by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Galloway, H.C.

    1995-12-01

    Detailed studies of the growth and structure of thin films of metal oxides grown on metal single crystal surfaces using Scanning Tunneling Microscopy (STM) are presented. The oxide overlayer systems studied are iron oxide and titanium oxide on the Pt(III) surface. The complexity of the metal oxides and large lattice mismatches often lead to surface structures with large unit cells. These are particularly suited to a local real space technique such as scanning tunneling microscopy. In particular, the symmetry that is directly observed with the STM elucidates the relationship of the oxide overlayers to the substrate as well as distinguishing, the structures of different oxides

  7. Inferential Structure Determination of Chromosomes from Single-Cell Hi-C Data

    Science.gov (United States)

    Nilges, Michael

    2016-01-01

    Chromosome conformation capture (3C) techniques have revealed many fascinating insights into the spatial organization of genomes. 3C methods typically provide information about chromosomal contacts in a large population of cells, which makes it difficult to draw conclusions about the three-dimensional organization of genomes in individual cells. Recently it became possible to study single cells with Hi-C, a genome-wide 3C variant, demonstrating a high cell-to-cell variability of genome organization. In principle, restraint-based modeling should allow us to infer the 3D structure of chromosomes from single-cell contact data, but suffers from the sparsity and low resolution of chromosomal contacts. To address these challenges, we adapt the Bayesian Inferential Structure Determination (ISD) framework, originally developed for NMR structure determination of proteins, to infer statistical ensembles of chromosome structures from single-cell data. Using ISD, we are able to compute structural error bars and estimate model parameters, thereby eliminating potential bias imposed by ad hoc parameter choices. We apply and compare different models for representing the chromatin fiber and for incorporating singe-cell contact information. Finally, we extend our approach to the analysis of diploid chromosome data. PMID:28027298

  8. Superconductor based ternary periodic multilayered structure as a single and multichanneled filter in the terahertz region.

    Science.gov (United States)

    D'souza, Nirmala Maria; Mathew, Vincent

    2017-08-20

    A single as well as a multichanneled filter in the terahertz region has been proposed by designing a one-dimensional photonic crystal (PhC) structure using a high-temperature superconductor air-dielectric ternary periodic structure. The filter is designed without incorporating any defect, which has rarely been proposed in a ternary PhC structure. The theoretical study of transmittance was performed by applying the transfer matrix method. The transition from single channel to desired multichannel is achieved by adjusting the number of periods. Furthermore, the impact of the thicknesses and dielectric constants of the constituting layers was investigated. In addition to this, the tunability is achieved by the influence of temperature-dependent dielectric constant of the superconductor.

  9. The advent of structural biologyin situby single particle cryo-electron tomography.

    Science.gov (United States)

    Galaz-Montoya, Jesús G; Ludtke, Steven J

    2017-01-01

    Single particle tomography (SPT), also known as subtomogram averaging, is a powerful technique uniquely poised to address questions in structural biology that are not amenable to more traditional approaches like X-ray crystallography, nuclear magnetic resonance, and conventional cryoEM single particle analysis. Owing to its potential for in situ structural biology at subnanometer resolution, SPT has been gaining enormous momentum in the last five years and is becoming a prominent, widely used technique. This method can be applied to unambiguously determine the structures of macromolecular complexes that exhibit compositional and conformational heterogeneity, both in vitro and in situ . Here we review the development of SPT, highlighting its applications and identifying areas of ongoing development.

  10. Evaluating the National Guard Domestic Operations Force Structure

    Science.gov (United States)

    2016-06-01

    proper method to ensure funding and resource availability was backward . Requirements should be identified, funding and resources then secured, followed...with a population of 1.5 million people and Tucson with greater than 500,000 people.40 In addition, Albuquerque, New Mexico is a major US city with...Science and Technology Directorate and National Guard Bureau, October 2013. p 5. 19 Jeffrey D. Stern, Elizabeth Nathaniel, Andrew Mosher, Howard

  11. Diverse and tunable electronic structures of single-layer metal phosphorus trichalcogenides for photocatalytic water splitting

    International Nuclear Information System (INIS)

    Liu, Jian; Li, Xi-Bo; Wang, Da; Liu, Li-Min; Lau, Woon-Ming; Peng, Ping

    2014-01-01

    The family of bulk metal phosphorus trichalcogenides (APX 3 , A = M II , M 0.5 I M 0.5 III ; X = S, Se; M I , M II , and M III represent Group-I, Group-II, and Group-III metals, respectively) has attracted great attentions because such materials not only own magnetic and ferroelectric properties, but also exhibit excellent properties in hydrogen storage and lithium battery because of the layered structures. Many layered materials have been exfoliated into two-dimensional (2D) materials, and they show distinct electronic properties compared with their bulks. Here we present a systematical study of single-layer metal phosphorus trichalcogenides by density functional theory calculations. The results show that the single layer metal phosphorus trichalcogenides have very low formation energies, which indicates that the exfoliation of single layer APX 3 should not be difficult. The family of single layer metal phosphorus trichalcogenides exhibits a large range of band gaps from 1.77 to 3.94 eV, and the electronic structures are greatly affected by the metal or the chalcogenide atoms. The calculated band edges of metal phosphorus trichalcogenides further reveal that single-layer ZnPSe 3 , CdPSe 3 , Ag 0.5 Sc 0.5 PSe 3 , and Ag 0.5 In 0.5 PX 3 (X = S and Se) have both suitable band gaps for visible-light driving and sufficient over-potentials for water splitting. More fascinatingly, single-layer Ag 0.5 Sc 0.5 PSe 3 is a direct band gap semiconductor, and the calculated optical absorption further convinces that such materials own outstanding properties for light absorption. Such results demonstrate that the single layer metal phosphorus trichalcogenides own high stability, versatile electronic properties, and high optical absorption, thus such materials have great chances to be high efficient photocatalysts for water-splitting

  12. National customer satisfaction indices: The impact of market structure

    DEFF Research Database (Denmark)

    Eskildsen, Jacob Kjær; Kristensen, Kai

    The popularity of customer satisfaction measurements has grown considerably over the last few years but we know very little about how the structure of the individual markets with respect to the transparency of products and services as well as consumer preferences affects customer satisfaction. Here...... a total of 14540 customers have evaluated their preferred supplier with respect to banking, property insurance, supermarkets and mobile telecom. The analysis shows that market structure has a profound effect on customer satisfaction measurements and that this effect differs from industry to industry....... The paper concludes with an evaluation of the implications of the findings in relation to the use of results from customer satisfaction studies....

  13. Method of growing yttrium aluminate and/or lanthanide single crystals with perovskite structure

    International Nuclear Information System (INIS)

    Kvapil, Jiri; Perner, B.; Kvapil, Josef; Blazek, K.

    1989-01-01

    Single crystals of yttrium aluminate and/or lanthanide with perovskite structure are grown from melt in a vacuum at a pressure of gas residues of max. 0.01 Pa. The melt contains 1±0.05 gram-ions of aluminium per gram-ion of yttrium and/or lanthanides. The single crystals are then heated in a vacuum (0.01 Pa) at temperatures of 1,450 to 1,800 degC for 2 to 3 hours. (B.S.)

  14. Magnetic properties and spin structure of MnO single crystal and powder

    Science.gov (United States)

    Sun, X.; Feng, E.; Su, Y.; Nemkovski, K.; Petracic, O.; Brückel, T.

    2017-06-01

    Zero field cooled (ZFC)/Field Cooled (FC) magnetization curves of a bulk MnO single crystal show a peculiar peak at low temperatures (~ 40 K) similar to the low temperature peak observed in MnO nanoparticles. In order to investigate the origin of this peak, the spin structure of a MnO single crystal has been studied and compared with a single phase powder sample using magnetometry and polarized neutron scattering. Both magnetometry and polarized neutron diffraction results confirm the antiferromagnetic (AF) phase transition at the Néel temperature TN of 118 K, in both powder and single crystal form. However, the low temperature peak in the ZFC/FC magnetization curves is not observed in single phase MnO powder. To better understand the observed behavior, ac susceptibility measurements have been employed. We conclude that the clear peak in the magnetic signal from the single crystal originates from a small amount of ferrimagnetic (FiM) Mn2O3 or Mn3O4 impurities, which is grown at the interfaces between MnO crystal twins.

  15. Proceedings of the third national conference on hierarchically structured materials

    International Nuclear Information System (INIS)

    2015-01-01

    Hierarchically structured materials and their technologies have been shaping human life and have been the key to present developments around the world. This conference emphasizes research efforts in this field need to be enhanced for the benefit of futuristic improvement. Papers relevant to INIS are indexed separately

  16. National conference on brittle fracture of materials and structures

    International Nuclear Information System (INIS)

    1990-12-01

    The proceedings contain full texts of 28 contributions, out of which 10 fall within the INIS subject scope. These deal particularly with the effect of neutron radiation on the brittle fracture properties of structural steels used in nuclear facilities and with theoretical problems of brittle fracture of such steels in cyclic stress conditions. (Z.M.)

  17. Determining Complex Structures using Docking Method with Single Particle Scattering Data

    Directory of Open Access Journals (Sweden)

    Haiguang Liu

    2017-04-01

    Full Text Available Protein complexes are critical for many molecular functions. Due to intrinsic flexibility and dynamics of complexes, their structures are more difficult to determine using conventional experimental methods, in contrast to individual subunits. One of the major challenges is the crystallization of protein complexes. Using X-ray free electron lasers (XFELs, it is possible to collect scattering signals from non-crystalline protein complexes, but data interpretation is more difficult because of unknown orientations. Here, we propose a hybrid approach to determine protein complex structures by combining XFEL single particle scattering data with computational docking methods. Using simulations data, we demonstrate that a small set of single particle scattering data collected at random orientations can be used to distinguish the native complex structure from the decoys generated using docking algorithms. The results also indicate that a small set of single particle scattering data is superior to spherically averaged intensity profile in distinguishing complex structures. Given the fact that XFEL experimental data are difficult to acquire and at low abundance, this hybrid approach should find wide applications in data interpretations.

  18. Determining Complex Structures using Docking Method with Single Particle Scattering Data.

    Science.gov (United States)

    Wang, Hongxiao; Liu, Haiguang

    2017-01-01

    Protein complexes are critical for many molecular functions. Due to intrinsic flexibility and dynamics of complexes, their structures are more difficult to determine using conventional experimental methods, in contrast to individual subunits. One of the major challenges is the crystallization of protein complexes. Using X-ray free electron lasers (XFELs), it is possible to collect scattering signals from non-crystalline protein complexes, but data interpretation is more difficult because of unknown orientations. Here, we propose a hybrid approach to determine protein complex structures by combining XFEL single particle scattering data with computational docking methods. Using simulations data, we demonstrate that a small set of single particle scattering data collected at random orientations can be used to distinguish the native complex structure from the decoys generated using docking algorithms. The results also indicate that a small set of single particle scattering data is superior to spherically averaged intensity profile in distinguishing complex structures. Given the fact that XFEL experimental data are difficult to acquire and at low abundance, this hybrid approach should find wide applications in data interpretations.

  19. Kink structures induced in nickel-based single crystal superalloys by high-Z element migration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fei; Zhang, Jianxin [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Mao, Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Jiang, Ying [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Feng, Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Zhenju; Li, Jixue; Zhang, Ze [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Xiaodong [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2015-01-05

    Highlights: • Innovative kink structures generate at the γ/γ′ interfaces in the crept superalloy. • Clusters of heavy elements congregate at the apex of the kinks. • Dislocation core absorbs hexagonal structural high-Z elements. - Abstract: Here, we investigate a new type of kink structure that is found at γ/γ′ interfaces in nickel-based single crystal superalloys. We studied these structures at the atomic and elemental level using aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The core of the dislocation absorbs high-Z elements (i.e., Co and Re) that adopt hexagonal arrangements, and it extrudes elements (i.e., Ni and Al) that adopt face centered cubic (fcc) structures. High-Z elements (i.e., Ta and W) and Cr, which is a low-Z element, are stabilized in body centered cubic (bcc) arrangements; Cr tends to behave like Re. High-Z elements, which migrate and adopt a hexagonal structure, induce kink formation at γ/γ′ interfaces. This process must be analyzed to fully understand the kinetics and dynamics of creep in nickel-based single crystal superalloys.

  20. Using machine learning to identify structural breaks in single-group interrupted time series designs.

    Science.gov (United States)

    Linden, Ariel; Yarnold, Paul R

    2016-12-01

    Single-group interrupted time series analysis (ITSA) is a popular evaluation methodology in which a single unit of observation is being studied, the outcome variable is serially ordered as a time series and the intervention is expected to 'interrupt' the level and/or trend of the time series, subsequent to its introduction. Given that the internal validity of the design rests on the premise that the interruption in the time series is associated with the introduction of the treatment, treatment effects may seem less plausible if a parallel trend already exists in the time series prior to the actual intervention. Thus, sensitivity analyses should focus on detecting structural breaks in the time series before the intervention. In this paper, we introduce a machine-learning algorithm called optimal discriminant analysis (ODA) as an approach to determine if structural breaks can be identified in years prior to the initiation of the intervention, using data from California's 1988 voter-initiated Proposition 99 to reduce smoking rates. The ODA analysis indicates that numerous structural breaks occurred prior to the actual initiation of Proposition 99 in 1989, including perfect structural breaks in 1983 and 1985, thereby casting doubt on the validity of treatment effects estimated for the actual intervention when using a single-group ITSA design. Given the widespread use of ITSA for evaluating observational data and the increasing use of machine-learning techniques in traditional research, we recommend that structural break sensitivity analysis is routinely incorporated in all research using the single-group ITSA design. © 2016 John Wiley & Sons, Ltd.

  1. Structure and magnetic properties of Co/Pt single- and bi-crystal multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.C. E-mail: yucc@phys.sinica.edu.tw; Chu, Y.C.; Chang, F.L.; Wei, D.H.; Chou, S.C.; Liou, Y.; Yao, Y.D.; Cheng, W.C.; Chin, T.S

    2004-11-01

    Both FCC(1 1 1) single- and bi-crystal [Co(3 A)]/Pt(10 A)]{sub 23} multilayers have been successfully grown on sapphire (0 0 0 1) and yttria-stabilized cubic zirconia (1 0 0) substrates, respectively, by molecular-beam epitaxial technique. The coercivity of single crystal films decreased monotonically as elevating post-annealing temperature. However, bicrystal films displayed a larger coercivity than the other. Moreover, the coercivity of bicrystal films did not decrease until the annealing temperature >400 deg. C. The difference in magnetic behavior between single- and bi-crystal multilayers could be originated from the demagnetizing factors resulted by different grain and surface structures.

  2. Should researchers use single indicators, best indicators, or multiple indicators in structural equation models?

    Directory of Open Access Journals (Sweden)

    Hayduk Leslie A

    2012-10-01

    Full Text Available Abstract Background Structural equation modeling developed as a statistical melding of path analysis and factor analysis that obscured a fundamental tension between a factor preference for multiple indicators and path modeling’s openness to fewer indicators. Discussion Multiple indicators hamper theory by unnecessarily restricting the number of modeled latents. Using the few best indicators – possibly even the single best indicator of each latent – encourages development of theoretically sophisticated models. Additional latent variables permit stronger statistical control of potential confounders, and encourage detailed investigation of mediating causal mechanisms. Summary We recommend the use of the few best indicators. One or two indicators are often sufficient, but three indicators may occasionally be helpful. More than three indicators are rarely warranted because additional redundant indicators provide less research benefit than single indicators of additional latent variables. Scales created from multiple indicators can introduce additional problems, and are prone to being less desirable than either single or multiple indicators.

  3. Structural modeling of dahlia-type single-walled carbon nanohorn aggregates by molecular dynamics.

    Science.gov (United States)

    Hawelek, L; Brodka, A; Dore, John C; Hannon, Alex C; Iijima, S; Yudasaka, M; Ohba, T; Kaneko, K; Burian, A

    2013-09-19

    The structure of dahlia-type single-walled carbon nanohorn aggregates has been modeled by classical molecular dynamics simulations, and the validity of the model has been verified by neutron diffraction. Computer-generated models consisted of an outer part formed from single-walled carbon nanohorns with diameters of 20-50 Å and a length of 400 Å and an inner turbostratic graphite-like core with a diameter of 130 Å. The diffracted intensity and the pair correlation function computed for such a constructed model are in good agreement with the neutron diffraction experimental data. The proposed turbostratic inner core explains the occurrence of the additional (002) and (004) graphitic peaks in the diffraction pattern of the studied sample and provides information about the interior structure of the dahlia-type aggregates.

  4. Spontaneous formation of structurally diverse membrane channel architectures from a single antimicrobial peptide

    Science.gov (United States)

    Wang, Yukun; Chen, Charles H.; Hu, Dan; Ulmschneider, Martin B.; Ulmschneider, Jakob P.

    2016-11-01

    Many antimicrobial peptides (AMPs) selectively target and form pores in microbial membranes. However, the mechanisms of membrane targeting, pore formation and function remain elusive. Here we report an experimentally guided unbiased simulation methodology that yields the mechanism of spontaneous pore assembly for the AMP maculatin at atomic resolution. Rather than a single pore, maculatin forms an ensemble of structurally diverse temporarily functional low-oligomeric pores, which mimic integral membrane protein channels in structure. These pores continuously form and dissociate in the membrane. Membrane permeabilization is dominated by hexa-, hepta- and octamers, which conduct water, ions and small dyes. Pores form by consecutive addition of individual helices to a transmembrane helix or helix bundle, in contrast to current poration models. The diversity of the pore architectures--formed by a single sequence--may be a key feature in preventing bacterial resistance and could explain why sequence-function relationships in AMPs remain elusive.

  5. Single molecule studies of surface-induced secondary structure in a model peptide

    Science.gov (United States)

    English, Douglas S.; Cunningham, Joy A.; Wehri, Sarah C.; Petrik, Amy F.; Okamoto, Kenji

    2004-10-01

    We have proposed using single molecule fluorescence resonant energy transfer (SM-FRET) to investigate the induction of secondary structure in model, surface-active peptides upon binding at an interface. The ability for SM-FRET to distinguish structural heterogeneity will offer a distinct advantage over traditional biophysical methods in these types of studies. Ensemble methods mask heterogeneity and only provide an average measure of secondary structural features. Because secondary structure contributes greatly to the energetics of dehydrating the amide backbone, detailed information of conformational distributions is crucial to the understanding of the thermodynamic cycle involved. Here we present results from our first efforts at using SM-FRET to study an amphipathic α-helix forming peptide immobilized at the solid-liquid interface between an aqueous solution and an octadecylsilane modified glass surface. This system serves as a model for future studies of peptide partitioning to lipid bilayers and other relevant interfaces.

  6. Ion assisted structural collapse of a single stranded DNA: A molecular dynamics approach

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Soumadwip; Dixit, Himanshu; Chakrabarti, Rajarshi, E-mail: rajarshi@chem.iitb.ac.in

    2015-09-28

    Highlights: • The dynamics of a single-stranded DNA in presence of different concentrations of Mg{sup 2+} is investigated. • The initial DNA chain collapse is characterized by the formation of non-sequentially stacked base pairs. • The DNA chain re-swells at high concentrations of Mg{sup 2+} as a consequence of overcharging. - Abstract: The structure and dynamics of negatively charged nucleic acids strongly correlate with the concentration and charge of the oppositely charged counterions. It is well known that the structural collapse of DNA is favoured in the presence of additional salt, a source of excess oppositely charged ions. Under such conditions single stranded DNA adopts a collapsed coil like conformation, typically characterized by stacking base pairs. Using atomistic molecular dynamics simulation, we demonstrate that in the presence of additional divalent salt (MgCl{sub 2}) single stranded DNA with base sequence 5′-CGCGAATTCGCG-3′ (Dickerson Drew dodecamer) initially collapses and then expands with increasing salt concentration. This is due to the overcharging induced DNA chain swelling, a dominant factor at a higher divalent salt concentration. In a nutshell, our simulations show how in the presence of divalent salt, non-sequential base stacking and overcharging competes and affect single stranded DNA dynamics unlike a monovalent salt.

  7. QAcon: single model quality assessment using protein structural and contact information with machine learning techniques.

    Science.gov (United States)

    Cao, Renzhi; Adhikari, Badri; Bhattacharya, Debswapna; Sun, Miao; Hou, Jie; Cheng, Jianlin

    2017-02-15

    Protein model quality assessment (QA) plays a very important role in protein structure prediction. It can be divided into two groups of methods: single model and consensus QA method. The consensus QA methods may fail when there is a large portion of low quality models in the model pool. In this paper, we develop a novel single-model quality assessment method QAcon utilizing structural features, physicochemical properties, and residue contact predictions. We apply residue-residue contact information predicted by two protein contact prediction methods PSICOV and DNcon to generate a new score as feature for quality assessment. This novel feature and other 11 features are used as input to train a two-layer neural network on CASP9 datasets to predict the quality of a single protein model. We blindly benchmarked our method QAcon on CASP11 dataset as the MULTICOM-CLUSTER server. Based on the evaluation, our method is ranked as one of the top single model QA methods. The good performance of the features based on contact prediction illustrates the value of using contact information in protein quality assessment. The web server and the source code of QAcon are freely available at: http://cactus.rnet.missouri.edu/QAcon. chengji@missouri.edu. Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  8. Coupling of a single active nanoparticle to a polymer-based photonic structure

    Directory of Open Access Journals (Sweden)

    Dam Thuy Trang Nguyen

    2016-03-01

    Full Text Available The engineered coupling between a guest moiety (molecule, nanoparticle and the host photonic nanostructure may provide a great enhancement of the guest optical response, leading to many attractive applications. In this article, we describe briefly the basic concept and some recent progress considering the coupling of a single nanoparticle into a photonic structure. Different kinds of nanoparticles of great interest including quantum dots and nitrogen-vacancy centers in nanodiamond for single photon source, nonlinear nanoparticles for efficient nonlinear effect and sensors, magnetic nanoparticles for Kerr magneto-optical effect, and plasmonic nanoparticles for ultrafast optical switching and sensors, are briefly reviewed. We focus further on the coupling of plasmonic gold nanoparticles and polymeric photonic structures by optimizing theoretically the photonic structures and developing efficient way to realize desired hybrid structures. The simple and low-cost fabrication technique, the optical enhancement of the fluorescent nanoparticles induced by the photonic structure, as well as the limitations, challenges and appealing prospects are discussed in details.

  9. Uncluttered Single-Image Visualization of Vascular Structures Using GPU and Integer Programming.

    Science.gov (United States)

    Won, Joong-Ho; Jeon, Yongkweon; Rosenberg, Jarrett K; Yoon, Sungroh; Rubin, Geoffrey D; Napel, Sandy

    2013-01-01

    Direct projection of 3D branching structures, such as networks of cables, blood vessels, or neurons onto a 2D image creates the illusion of intersecting structural parts and creates challenges for understanding and communication. We present a method for visualizing such structures, and demonstrate its utility in visualizing the abdominal aorta and its branches, whose tomographic images might be obtained by computed tomography or magnetic resonance angiography, in a single 2D stylistic image, without overlaps among branches. The visualization method, termed uncluttered single-image visualization (USIV), involves optimization of geometry. This paper proposes a novel optimization technique that utilizes an interesting connection of the optimization problem regarding USIV to the protein structure prediction problem. Adopting the integer linear programming-based formulation for the protein structure prediction problem, we tested the proposed technique using 30 visualizations produced from five patient scans with representative anatomical variants in the abdominal aortic vessel tree. The novel technique can exploit commodity-level parallelism, enabling use of general-purpose graphics processing unit (GPGPU) technology that yields a significant speedup. Comparison of the results with the other optimization technique previously reported elsewhere suggests that, in most aspects, the quality of the visualization is comparable to that of the previous one, with a significant gain in the computation time of the algorithm.

  10. Strain-hardening in nano-structured single phase steels: mechanisms and control.

    Science.gov (United States)

    Bouaziz, O; Barbier, D

    2012-11-01

    The detrimental effect of grain size refinement on the strain hardening is highlighted in single phase steels. A physical based approach for understanding the underlying mechanisms is presented. In order to overcome this limitation a promising metallurgical route exploiting the thermal stability of mechanically induced twins in austenitic steels has been successfully applied to a stainless grade confirming the opportunity to get nano-structured alloys exhibiting high yield stress with high strain-hardening.

  11. Macromolecular X-ray structure determination using weak, single-wavelength anomalous data

    Energy Technology Data Exchange (ETDEWEB)

    Bunkóczi, Gábor; McCoy, Airlie J.; Echols, Nathaniel; Grosse-Kunstleve, Ralf W.; Adams, Paul D.; Holton, James M.; Read, Randy J.; Terwilliger, Thomas C.

    2014-12-22

    We describe a likelihood-based method for determining the substructure of anomalously scattering atoms in macromolecular crystals that allows successful structure determination by single-wavelength anomalous diffraction (SAD) X-ray analysis with weak anomalous signal. With the use of partial models and electron density maps in searches for anomalously scattering atoms, testing of alternative values of parameters and parallelized automated model-building, this method has the potential to extend the applicability of the SAD method in challenging cases.

  12. single crystal growth, x-ray structure analysis, optical band gap

    African Journals Online (AJOL)

    2015-09-01

    Sep 1, 2015 ... Hg...Hgand Cl...Cl interactions are stabilizing the structures in 3D pattern. UV-vis absorption spectra illustrate the change in opticalband gap from 3.01eVto 3.42eV on replacing the metal halide group.Raman and Hyper-Raman tensors calculations were performed based on single crystal X-ray data and the ...

  13. Control of the structural parameters in the (Zn – Zn16Ti single crystal growth

    Directory of Open Access Journals (Sweden)

    W. Wołczyński

    2011-10-01

    Full Text Available The (Zn - single crystal was obtained by means of the Bridgman system. Several growth rates were applied during the experiment. The graphite crucible was used in order to perform the solidification process. The unidirectional solidification occurred with the presence of the moving temperature field. The thermal gradient was positive so that the constrained growth of the single crystal was ensured. The (Zn single crystal was doped with small addition of titanium and copper. The titanium formed an intermetallic compound Zn16-Ti. The copper was solved in the solid solution (Zn. The precipitates of (Zn and Zn16-Ti formed a stripes localized cyclically along the single crystal length. The intermetallic compound Zn16-Ti strengthened the (Zn single crystal. The structural transitions were observed in the stripes with the increasing solidification rate. Within the first range of the solidification rates ( the irregular L-shape rod-like intermetalliccompoundwas revealed. At the- threshold growth rate branches disappear continuously till the growth rate equal to. At the same range of growth rates the regular lamellar eutectic structure (Zn – Zn16-Ti appeared continuously and it existed exclusively till the second threshold growth rate equal to. Above the second threshold growth rate the regular rod-like eutectic structure was formed, only. Thegeneral theory for the stationary eutectic solidification was developed. According to this theory the eutectic structure localized within the stripes is formed under stationary state. Therefore, the criterion of the minimum entropy production defines well the stationary solidification. The entropy production was calculated for the regular rod-like eutectic structure formation and for the regular lamellar eutectic structure formation. It was postulated that the observed structure are subjected to the competition. That is why the structural transitionwere observed at therevealedthreshold growth rates.Moreover, it was

  14. Development of a single logistic process for the South African National Defence Force

    CSIR Research Space (South Africa)

    Schmitz, Peter MU

    2010-09-01

    Full Text Available The South African National Defence Force (SANDF) contracted the CSIR to investigate and propose methods to improve its logistics and inventory accounting capabilities. The CSIR proposed that a supply chain management approach should be followed...

  15. National Hypersonic Science Center for Materials and Structures

    Science.gov (United States)

    2014-08-31

    on sintering and/or stability of the oxidation products (ZrO2, B-O glasses, and B-Si-O glasses). The UTA group used atomistic calculations to...free” carbon was performed at UTA . Particular emphasis was placed on possible interface structures that may connect the “free” carbon phase to the...carried out in the NHSC program. One is a DARPA program in which UTA (P. Kroll) is teamed with Teledyne (O. Sudre) to find new chemical routes for

  16. Subsurface defects structural evolution in nano-cutting of single crystal copper

    International Nuclear Information System (INIS)

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Sun, Yazhou; Guo, Yongbo; Liang, Yingchun

    2015-01-01

    Highlights: • An innovative analysis method is adopted to analyze nano-cutting process accurately. • A characteristic SFT and stair-rod dislocation are found in subsurface defect layer. • The formation mechanism of stair-rod dislocation is investigated. • The local atomic structure of subsurface defects is introduced. - Abstract: In this work, molecular dynamics simulation is performed to study the subsurface defects structural distribution and its evolution during nano-cutting process of single crystal copper. The formation mechanism of chip and machined surface is interviewed by analyzing the dislocation evolution and atomic migration. The centro-symmetry parameter and spherical harmonics method are adopted to characterize the distribution and evolution of the subsurface defect structures and local atomic structures. The results show that stacking faults, dislocation loops, “V-shaped” dislocation loops, and plenty of point defects are formed during the machined surface being formed in shear-slip zone. In subsurface damage layers, stair-rod dislocation, stacking fault tetrahedra, atomic cluster defect, and vacancy defect are formed. And the formation mechanism of stair-rod dislocation is investigated by atomic-scale structure evolution. The local atomic structures of subsurface defects are icosahedrons, hexagonal close packed, body-centered cubic, and defect face center cubic, and the variations of local atomic structures are investigated

  17. Correlation between modulation structure and electronic inhomogeneity on Pb-doped Bi-2212 single crystals

    International Nuclear Information System (INIS)

    Sugimoto, A.; Kashiwaya, S.; Eisaki, H.; Yamaguchi, H.; Oka, K.; Kashiwaya, H.; Tsuchiura, H.; Tanaka, Y.

    2005-01-01

    The correlation between nanometer-size electronic states and surface structure is investigated by scanning tunneling microscopy/spectroscopy (STM/S) on Pb-doped Bi 2-x Pb x Sr 2 CaCu2O 8+y (Pb-Bi-2212) single crystals. The advantage of the Pb-Bi-2212 samples is that the modulation structure can be totally or locally suppressed depending on the Pb contents and annealing conditions. The superconducting gap (Δ) distribution on modulated Pb-Bi-2212 samples showed the lack of correlation with modulation structure except a slight reduction of superconducting island size for the b-axis direction. On the other hand, the optimal doped Pb-Bi-2212 (x = 0.6) samples obtained by reduced-annealing showed totally non-modulated structure in topography, however, the spatial distribution of Δ still showed inhomogeneity of which features were quite similar to those of modulated samples. These results suggest that the modulation structure is not the dominant origin of inhomogeneity although it modifies the streaky Δ structure sub-dominantly. From the gap structure variation around the border of narrow gap and broad gap regions, a trend of the coexistence of two separated phases i.e., superconducting phase and pseudogap like phase, is detected

  18. Accelerated safety analyses - structural analyses Phase I - structural sensitivity evaluation of single- and double-shell waste storage tanks

    International Nuclear Information System (INIS)

    Becker, D.L.

    1994-11-01

    Accelerated Safety Analyses - Phase I (ASA-Phase I) have been conducted to assess the appropriateness of existing tank farm operational controls and/or limits as now stipulated in the Operational Safety Requirements (OSRs) and Operating Specification Documents, and to establish a technical basis for the waste tank operating safety envelope. Structural sensitivity analyses were performed to assess the response of the different waste tank configurations to variations in loading conditions, uncertainties in loading parameters, and uncertainties in material characteristics. Extensive documentation of the sensitivity analyses conducted and results obtained are provided in the detailed ASA-Phase I report, Structural Sensitivity Evaluation of Single- and Double-Shell Waste Tanks for Accelerated Safety Analysis - Phase I. This document provides a summary of the accelerated safety analyses sensitivity evaluations and the resulting findings

  19. Electronic fine structure and recombination dynamics in single InAs quantum dots

    International Nuclear Information System (INIS)

    Seguin, R.

    2008-01-01

    In the work at hand single InAs/GaAs quantum dots (QDs) are examined via cathodoluminescence spectroscopy. A thorough analysis of the spectra leads to an unambiguous assignment of the lines to the decay of specific excitonic complexes. A special aspect of the Coulomb interaction, the exchange interaction, gives rise to a fine structure in the initial and final states of an excitonic decay. This leads to a fine structure in the emission spectra that again is unique for every excitonic complex. The exchange interaction is discussed in great detail in this work.QDs of different sizes are investigated and the influence on the electronic properties is monitored. Additionally, the structure is modified ex situ by a thermal annealing process. The changes of the spectra under different annealing temperatures are traced. Finally, recombination dynamics of different excitonic complexes are examined by performing time-resolved cathodoluminescence spectroscopy. (orig.)

  20. Microwave measurements of energy lost to longitudinal modes by single electron bunches traversing periodic structures

    International Nuclear Information System (INIS)

    Wang, J.W.; Loew, G.A.; Weaver, J.N.; Wilson, P.B.

    1981-10-01

    In the design of future linear colliders, it will be important to minimize the loss of beam energy due to the excitation of higher-order modes in the accelerator structure by single bunches of electrons or positrons. This loss is not only detrimental in itself but also gives rise to energy spectrum widening and transverse emittance growth. Microwave measurements made on disk-loaded and alternating-spoke structures to determine the loss to the longitudinal modes are described. In these measurements the Gaussian bunch is simulated by a current pulse of the same shape transmitted through the structure on an axial center conductor. Results to date are presented for the total longitudinal loss parameter per period K in volts per picocoulomb

  1. Electronic fine structure and recombination dynamics in single InAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Seguin, R.

    2008-01-28

    In the work at hand single InAs/GaAs quantum dots (QDs) are examined via cathodoluminescence spectroscopy. A thorough analysis of the spectra leads to an unambiguous assignment of the lines to the decay of specific excitonic complexes. A special aspect of the Coulomb interaction, the exchange interaction, gives rise to a fine structure in the initial and final states of an excitonic decay. This leads to a fine structure in the emission spectra that again is unique for every excitonic complex. The exchange interaction is discussed in great detail in this work.QDs of different sizes are investigated and the influence on the electronic properties is monitored. Additionally, the structure is modified ex situ by a thermal annealing process. The changes of the spectra under different annealing temperatures are traced. Finally, recombination dynamics of different excitonic complexes are examined by performing time-resolved cathodoluminescence spectroscopy. (orig.)

  2. Single-particle structure determination by correlations of snapshot X-ray diffraction patterns

    Science.gov (United States)

    Starodub, D.; Aquila, A.; Bajt, S.; Barthelmess, M.; Barty, A.; Bostedt, C.; Bozek, J. D.; Coppola, N.; Doak, R. B.; Epp, S. W.; Erk, B.; Foucar, L.; Gumprecht, L.; Hampton, C. Y.; Hartmann, A.; Hartmann, R.; Holl, P.; Kassemeyer, S.; Kimmel, N.; Laksmono, H.; Liang, M.; Loh, N. D.; Lomb, L.; Martin, A. V.; Nass, K.; Reich, C.; Rolles, D.; Rudek, B.; Rudenko, A.; Schulz, J.; Shoeman, R. L.; Sierra, R. G.; Soltau, H.; Steinbrener, J.; Stellato, F.; Stern, S.; Weidenspointner, G.; Frank, M.; Ullrich, J.; Strüder, L.; Schlichting, I.; Chapman, H. N.; Spence, J. C. H.; Bogan, M. J.

    2012-12-01

    Diffractive imaging with free-electron lasers allows structure determination from ensembles of weakly scattering identical nanoparticles. The ultra-short, ultra-bright X-ray pulses provide snapshots of the randomly oriented particles frozen in time, and terminate before the onset of structural damage. As signal strength diminishes for small particles, the synthesis of a three-dimensional diffraction volume requires simultaneous involvement of all data. Here we report the first application of a three-dimensional spatial frequency correlation analysis to carry out this synthesis from noisy single-particle femtosecond X-ray diffraction patterns of nearly identical samples in random and unknown orientations, collected at the Linac Coherent Light Source. Our demonstration uses unsupported test particles created via aerosol self-assembly, and composed of two polystyrene spheres of equal diameter. The correlation analysis avoids the need for orientation determination entirely. This method may be applied to the structural determination of biological macromolecules in solution.

  3. 3 ns single-shot read-out in a quantum dot-based memory structure

    International Nuclear Information System (INIS)

    Nowozin, T.; Bimberg, D.; Beckel, A.; Lorke, A.; Geller, M.

    2014-01-01

    Fast read-out of two to six charges per dot from the ground and first excited state in a quantum dot (QD)-based memory is demonstrated using a two-dimensional electron gas. Single-shot measurements on modulation-doped field-effect transistor structures with embedded InAs/GaAs QDs show read-out times as short as 3 ns. At low temperature (T = 4.2 K) this read-out time is still limited by the parasitics of the setup and the device structure. Faster read-out times and a larger read-out signal are expected for an improved setup and device structure

  4. Nonlinear evolution of single spike structure and vortex in Richtmeyer-Meshkov instability

    International Nuclear Information System (INIS)

    Fukuda, Yuko O.; Nishihara, Katsunobu; Okamoto, Masayo; Nagatomo, Hideo; Matsuoka, Chihiro; Ishizaki, Ryuichi; Sakagami, Hitoshi

    1999-01-01

    Nonlinear evolution of single spike structure and vortex in the Richtmyer-Meshkov instability is investigated for two dimensional case, and axial symmetric and non axial symmetric cases with the use of a three-dimensional hydrodynamic code. It is shown that singularity appears in the vorticity left by transmitted and reflected shocks at a corrugated interface. This singularity results in opposite sign of vorticity along the interface that causes double spiral structure of the spike. Difference of nonlinear growth rate and double spiral structure among three cases is also discussed by visualization of simulation data. In a case that there is no slip-off of initial spike axis, vorticity ring is relatively stable, but phase rotation occurs. (author)

  5. Single Event Effects Test Facility Options at the Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Riemer, Bernie [ORNL; Gallmeier, Franz X [ORNL; Dominik, Laura J [ORNL

    2015-01-01

    Increasing use of microelectronics of ever diminishing feature size in avionics systems has led to a growing Single Event Effects (SEE) susceptibility arising from the highly ionizing interactions of cosmic rays and solar particles. Single event effects caused by atmospheric radiation have been recognized in recent years as a design issue for avionics equipment and systems. To ensure a system meets all its safety and reliability requirements, SEE induced upsets and potential system failures need to be considered, including testing of the components and systems in a neutron beam. Testing of integrated circuits (ICs) and systems for use in radiation environments requires the utilization of highly advanced laboratory facilities that can run evaluations on microcircuits for the effects of radiation. This paper provides a background of the atmospheric radiation phenomenon and the resulting single event effects, including single event upset (SEU) and latch up conditions. A study investigating requirements for future single event effect irradiation test facilities and developing options at the Spallation Neutron Source (SNS) is summarized. The relatively new SNS with its 1.0 GeV proton beam, typical operation of 5000 h per year, expertise in spallation neutron sources, user program infrastructure, and decades of useful life ahead is well suited for hosting a world-class SEE test facility in North America. Emphasis was put on testing of large avionics systems while still providing tunable high flux irradiation conditions for component tests. Makers of ground-based systems would also be served well by these facilities. Three options are described; the most capable, flexible, and highest-test-capacity option is a new stand-alone target station using about one kW of proton beam power on a gas-cooled tungsten target, with dual test enclosures. Less expensive options are also described.

  6. The Structure Of Drinking Motives in First Nations Adolescents in Nova Scotia

    Science.gov (United States)

    Mushquash, Christopher J.; Stewart, Sherry H.; Comeau, Nancy; McGrath, Patrick J.

    2008-01-01

    Objective: The factor structure of the Drinking Motives Questionnaire-Revised (DMQ-R; Cooper, 1994) was examined in a sample of First Nations (i.e., Mi'kmaq) adolescents. Results: Exploratory principal components analysis indicated a three-factor structure (conformity, coping, and positive reinforcement motives), with the positive reinforcement…

  7. Studying the structural dynamics of bipedal DNA motors with single-molecule fluorescence spectroscopy.

    Science.gov (United States)

    Masoud, Rula; Tsukanov, Roman; Tomov, Toma E; Plavner, Noa; Liber, Miran; Nir, Eyal

    2012-07-24

    We present a test case example of a detailed single-molecule fluorescence study of one of the most sophisticated and complex DNA devices introduced to date, a recently published autonomous bipedal DNA motor. We used the diffusion-based single-molecule Förster resonance energy transfer technique, coupled to alternating laser excitation (sm-FRET-ALEX), to monitor the motor assembly and operation. The study included verification of the formation of the correct structures, and of the correct motor operation, determination of the formation and stepping reaction yields, and identification of side products. Finally, the mechanisms of the motor assembly and operation were elucidated by measuring the reaction kinetics profile of track-walker binding and of lifting of the walker's leg upon fuel addition. The profiles revealed a fast phase, in which about half of the reaction was completed, followed by a slow phase which adds somewhat to the yield, reflecting the incomplete motor assembly and operation identified in the equilibrium experiments. Although further study is needed to fully understand the reasons for the incomplete assembly and operation, this work demonstrates that single-molecule fluorescence, based on its ability to provide detailed in situ structural dynamics information, inaccessible for traditional methods, constitutes an excellent tool for chaperoning the development of DNA-based technology.

  8. Structure and Reactions of 11Be: Many-Body Basis for Single-Neutron Halo

    Science.gov (United States)

    Barranco, F.; Potel, G.; Broglia, R. A.; Vigezzi, E.

    2017-08-01

    The exotic nucleus 11Be has been extensively studied and much experimental information is available on the structure of this system. We treat, within the framework of renormalized nuclear field theory in both configuration and 3D space, the mixing of bound and continuum single-particle states through the coupling to collective vibrations of the 10Be core. We also take care of the Pauli principle acting not only between the single valence particle explicitly considered and those participating in the collective states, but also between fermions involved in two-phonon virtual states dressing the single-particle motion. In this way, it is possible to simultaneously and quantitatively account for the energies of the 1 /2+ , 1 /2- low-lying states, the centroid and line shape of the 5 /2+ resonance and the one-nucleon stripping and pickup absolute differential cross sections involving 11Be as either target or residual nucleus. Also for the dipole transition connecting the 1 /2+ and 1 /2- parity inverted levels as well as the isotopic shift of the charge radius. Theory provides a unified and exhaustive nuclear structure and reaction characterization of the many-body effects which are at the basis of this paradigmatic one-neutron halo system.

  9. Communication: The electronic structure of matter probed with a single femtosecond hard x-ray pulse

    Directory of Open Access Journals (Sweden)

    J. Szlachetko

    2014-03-01

    Full Text Available Physical, biological, and chemical transformations are initiated by changes in the electronic configuration of the species involved. These electronic changes occur on the timescales of attoseconds (10−18 s to femtoseconds (10−15 s and drive all subsequent electronic reorganization as the system moves to a new equilibrium or quasi-equilibrium state. The ability to detect the dynamics of these electronic changes is crucial for understanding the potential energy surfaces upon which chemical and biological reactions take place. Here, we report on the determination of the electronic structure of matter using a single self-seeded femtosecond x-ray pulse from the Linac Coherent Light Source hard x-ray free electron laser. By measuring the high energy resolution off-resonant spectrum (HEROS, we were able to obtain information about the electronic density of states with a single femtosecond x-ray pulse. We show that the unoccupied electronic states of the scattering atom may be determined on a shot-to-shot basis and that the measured spectral shape is independent of the large intensity fluctuations of the incoming x-ray beam. Moreover, we demonstrate the chemical sensitivity and single-shot capability and limitations of HEROS, which enables the technique to track the electronic structural dynamics in matter on femtosecond time scales, making it an ideal probe technique for time-resolved X-ray experiments.

  10. Extracting 3D layout from a single image using global image structures.

    Science.gov (United States)

    Lou, Zhongyu; Gevers, Theo; Hu, Ninghang

    2015-10-01

    Extracting the pixel-level 3D layout from a single image is important for different applications, such as object localization, image, and video categorization. Traditionally, the 3D layout is derived by solving a pixel-level classification problem. However, the image-level 3D structure can be very beneficial for extracting pixel-level 3D layout since it implies the way how pixels in the image are organized. In this paper, we propose an approach that first predicts the global image structure, and then we use the global structure for fine-grained pixel-level 3D layout extraction. In particular, image features are extracted based on multiple layout templates. We then learn a discriminative model for classifying the global layout at the image-level. Using latent variables, we implicitly model the sublevel semantics of the image, which enrich the expressiveness of our model. After the image-level structure is obtained, it is used as the prior knowledge to infer pixel-wise 3D layout. Experiments show that the results of our model outperform the state-of-the-art methods by 11.7% for 3D structure classification. Moreover, we show that employing the 3D structure prior information yields accurate 3D scene layout segmentation.

  11. 3D structure determination of protein using TEM single particle analysis.

    Science.gov (United States)

    Sato, Chikara; Mio, Kazuhiro; Kawata, Masaaki; Ogura, Toshihiko

    2014-11-01

    Proteins play important roles in cell functions such as enzymes, cell trafficking, neurotransmission, muscle contraction and hormone secretion. However, some proteins are very difficult to be crystallized and their structures are undetermined. Several techniques have been developed to elucidate the structure of macromolecules; X-ray or electron crystallography, nuclear magnetic resonance spectroscopy, and high-resolution electron microscopy. Among them, electron microscopy based single particle reconstruction (SPA) technique is a computer-aided structure determination method. This method reconstructs the 3D structure from projection images of dispersed protein. A large number of two-dimensional particle images are picked up from EM films, aligned and classified to generate 2D averages, and used to reconstruct the 3D structure by assigning the Euler angle of each 2D average. Due to the necessity of elaborate collaboration between the classical biology and the innovative information technology including parallel computing, scientists needed to break unseen barriers to get a start of this analysis. However, recent progresses in electron microscopes, mathematical algorithms, and computational abilities greatly reduced the height of barriers and expanded targets that are considered to be primarily addressable using single particle analysis. Membrane proteins are one of these targets to which the single particle analysis is successfully applied for the understanding of their 3D structures. For this purpose, we have developed various SPA methods [1-5] and applied them to different proteins [6-8].Here, we introduce reconstructed proteins, and discuss the availability of this technique. The intramembrane-cleaving proteases (I-CLiPs) that sever the transmembrane domains of their substrates have been identified in a range of organisms and play a variety of roles in biological conditions. I-CLiPs have been classified into three groups: serine-, aspartyl- and metalloprotease

  12. Single molecule tools for enzymology, structural biology, systems biology and nanotechnology: an update

    Science.gov (United States)

    Widom, Julia R.; Dhakal, Soma; Heinicke, Laurie A.; Walter, Nils G.

    2015-01-01

    Toxicology is the highly interdisciplinary field studying the adverse effects of chemicals on living organisms. It requires sensitive tools to detect such effects. After their initial implementation during the 1990s, single-molecule fluorescence detection tools were quickly recognized for their potential to contribute greatly to many different areas of scientific inquiry. In the intervening time, technical advances in the field have generated ever-improving spatial and temporal resolution, and have enabled the application of single-molecule fluorescence to increasingly complex systems, such as live cells. In this review, we give an overview of the optical components necessary to implement the most common versions of single-molecule fluorescence detection. We then discuss current applications to enzymology and structural studies, systems biology, and nanotechnology, presenting the technical considerations that are unique to each area of study, along with noteworthy recent results. We also highlight future directions that have the potential to revolutionize these areas of study by further exploiting the capabilities of single-molecule fluorescence microscopy. PMID:25212907

  13. Shedding Light on Protein Folding, Structural and Functional Dynamics by Single Molecule Studies

    Directory of Open Access Journals (Sweden)

    Krutika Bavishi

    2014-11-01

    Full Text Available The advent of advanced single molecule measurements unveiled a great wealth of dynamic information revolutionizing our understanding of protein dynamics and behavior in ways unattainable by conventional bulk assays. Equipped with the ability to record distribution of behaviors rather than the mean property of a population, single molecule measurements offer observation and quantification of the abundance, lifetime and function of multiple protein states. They also permit the direct observation of the transient and rarely populated intermediates in the energy landscape that are typically averaged out in non-synchronized ensemble measurements. Single molecule studies have thus provided novel insights about how the dynamic sampling of the free energy landscape dictates all aspects of protein behavior; from its folding to function. Here we will survey some of the state of the art contributions in deciphering mechanisms that underlie protein folding, structural and functional dynamics by single molecule fluorescence microscopy techniques. We will discuss a few selected examples highlighting the power of the emerging techniques and finally discuss the future improvements and directions.

  14. Development of NUPREP PC Version and Input Structures for NUCIRC Single Channel Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Churl; Jun, Ji Su; Park, Joo Hwan

    2007-12-15

    The input file for a steady-state thermal-hydraulic code NUCIRC consists of common channel input data and specific channel input data in a case of single channel analysis. Even when all the data is ready for the 380 channels' single channel analyses, it takes long time and requires enormous effort to compose an input file by hand-editing. The automatic pre-processor for this tedious job is a NUPREP code. In this study, a NUPREP PC version has been developed from the source list in the program manual of NUCIRC-MOD2.000 that is imported in a form of an execution file. In this procedure, some errors found in PC executions and lost statements are fixed accordingly. It is confirmed that the developed NUPREP code produces input file correctly for the CANDU-6 single channel analysis. Additionally, the NUCIRC input structure and data format are summarized for a single channel analysis and the input CARDs required for the creep information of aged channels are listed.

  15. Development of NUPREP PC Version and Input Structures for NUCIRC Single Channel Analyses

    International Nuclear Information System (INIS)

    Yoon, Churl; Jun, Ji Su; Park, Joo Hwan

    2007-12-01

    The input file for a steady-state thermal-hydraulic code NUCIRC consists of common channel input data and specific channel input data in a case of single channel analysis. Even when all the data is ready for the 380 channels' single channel analyses, it takes long time and requires enormous effort to compose an input file by hand-editing. The automatic pre-processor for this tedious job is a NUPREP code. In this study, a NUPREP PC version has been developed from the source list in the program manual of NUCIRC-MOD2.000 that is imported in a form of an execution file. In this procedure, some errors found in PC executions and lost statements are fixed accordingly. It is confirmed that the developed NUPREP code produces input file correctly for the CANDU-6 single channel analysis. Additionally, the NUCIRC input structure and data format are summarized for a single channel analysis and the input CARDs required for the creep information of aged channels are listed

  16. Edge structures and properties of triangular antidots in single-layer MoS2

    KAUST Repository

    Gan, Li Yong

    2016-08-30

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS2. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS2 samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS2 devices. Published by AIP Publishing.

  17. Single shot near edge x-ray absorption fine structure spectroscopy in the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Mantouvalou, I., E-mail: ioanna.mantouvalou@tu-berlin.de; Witte, K.; Martyanov, W.; Jonas, A.; Grötzsch, D.; Kanngießer, B. [Institute for Optics and Atomic Physics, Technical University of Berlin, D-10623 Berlin (Germany); Streeck, C. [Physikalisch-Technische Bundesanstalt (PTB), D-10587 Berlin (Germany); Löchel, H.; Rudolph, I.; Erko, A. [Helmholtz-Zentrum Berlin, D-14109 Berlin (Germany); Stiel, H. [Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, D-12489 Berlin (Germany)

    2016-05-16

    With the help of adapted off-axis reflection zone plates, near edge X-ray absorption fine structure spectra at the C and N K-absorption edge have been recorded using a single 1.2 ns long soft X-ray pulse. The transmission experiments were performed with a laser-produced plasma source in the laboratory rendering time resolved measurements feasible independent on large scale facilities. A resolving power of E/ΔE ∼ 950 at the respective edges could be demonstrated. A comparison of single shot spectra with those collected with longer measuring time proves that all features of the used reference samples (silicon nitrate and polyimide) can be resolved in 1.2 ns. Hence, investigations of radiation sensitive biological specimen become possible due to the high efficiency of the optical elements enabling low dose experiments.

  18. Surface structure modification of single crystal graphite after slow, highly charged ion irradiation

    Science.gov (United States)

    Alzaher, I.; Akcöltekin, S.; Ban-d'Etat, B.; Manil, B.; Dey, K. R.; Been, T.; Boduch, P.; Rothard, H.; Schleberger, M.; Lebius, H.

    2018-04-01

    Single crystal graphite was irradiated by slow, highly charged ions. The modification of the surface structure was studied by means of Low-Energy Electron Diffraction. The observed damage cross section increases with the potential energy, i.e. the charge state of the incident ion, at a constant kinetic energy. The potential energy is more efficient for the damage production than the kinetic energy by more than a factor of twenty. Comparison with earlier results hints to a strong link between early electron creation and later target atom rearrangement. With increasing ion fluence, the initially large-scale single crystal is first transformed into μ m-sized crystals, before complete amorphisation takes place.

  19. Finite Element Analysis of Doorframe Structure of Single Oblique Pole Type in Container Crane

    Science.gov (United States)

    Cheng, X. F.; Wu, F. Q.; Tang, G.; Hu, X.

    2017-07-01

    Compared with the composite type, the single oblique pole type has more advantages, such as simple structure, thrift steel and high safe overhead clearance. The finite element model of the single oblique pole type is established in nodes by ANSYS, and more details are considered when the model is simplified, such as the section of Girder and Boom, torque in Girder and Boom occurred by Machinery house and Trolley, density according to the way of simplification etc. The stress and deformation of ten observation points are compared and analyzed, when the trolley is in nine dangerous positions. Based on the result of analysis, six dangerous points are selected to provide reference for the detection and evaluation of container crane.

  20. Edge structures and properties of triangular antidots in single-layer MoS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Li-Yong, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, Yingchun, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa; Huang, Wei [Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials - SICAM, Nanjing Tech University - NanjingTech, 30 South Puzhu Road, Nanjing 211816 (China); Schwingenschlögl, Udo, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa [Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Yao, Yingbang [Advanced Nanofabrication and Imaging Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); School of Materials and Energy, Guangdong University of Technology, Guangdong 510006 (China); Zhao, Yong [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, 610031 Sichuan (China); Zhang, Xi-xiang [Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Advanced Nanofabrication and Imaging Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)

    2016-08-29

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS{sub 2}. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS{sub 2} samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS{sub 2} devices.

  1. The Structures of Self-Assembled Monolayer Films of Organosulfur Compounds Adsorbed on Gold Single Crystals: Electron Diffraction Studies.

    Science.gov (United States)

    1988-01-01

    AD-M193 125 THE STRUCTURES OF SELF-RSSENSLED MOMOLAYER FILMS OF 1/1 ORGANOSULFUR COMPOUND..(U) HRlYARD UNJY CAMBRIDGE MASS DEPT OF CHEMISTRY L STRONG...VV L- ___ THE STRUCTURES OF SELF-ASSEMBLED MONOLAYER FILMS OF ORGANOSULFUR COMPOUNDS ADSORBED ON GOLD SINGLE CRYSTALS: ELECTRON DIFFRACTION STUDIES...true sulfide phase. V V ’A. LA8700876 REVISED The Structures of Self-Assembled Monolayer Films of Organosulfur Compounds Adsorbed on Gold Single

  2. Relationships among the structural topology, bond strength, and mechanical properties of single-walled aluminosilicate nanotubes.

    Science.gov (United States)

    Liou, Kai-Hsin; Tsou, Nien-Ti; Kang, Dun-Yen

    2015-10-21

    Carbon nanotubes (CNTs) are regarded as small but strong due to their nanoscale microstructure and high mechanical strength (Young's modulus exceeds 1000 GPa). A longstanding question has been whether there exist other nanotube materials with mechanical properties as good as those of CNTs. In this study, we investigated the mechanical properties of single-walled aluminosilicate nanotubes (AlSiNTs) using a multiscale computational method and then conducted a comparison with single-walled carbon nanotubes (SWCNTs). By comparing the potential energy estimated from molecular and macroscopic material mechanics, we were able to model the chemical bonds as beam elements for the nanoscale continuum modeling. This method allowed for simulated mechanical tests (tensile, bending, and torsion) with minimum computational resources for deducing their Young's modulus and shear modulus. The proposed approach also enabled the creation of hypothetical nanotubes to elucidate the relative contributions of bond strength and nanotube structural topology to overall nanotube mechanical strength. Our results indicated that it is the structural topology rather than bond strength that dominates the mechanical properties of the nanotubes. Finally, we investigated the relationship between the structural topology and the mechanical properties by analyzing the von Mises stress distribution in the nanotubes. The proposed methodology proved effective in rationalizing differences in the mechanical properties of AlSiNTs and SWCNTs. Furthermore, this approach could be applied to the exploration of new high-strength nanotube materials.

  3. Monolithic carbon structures including suspended single nanowires and nanomeshes as a sensor platform.

    Science.gov (United States)

    Lim, Yeongjin; Heo, Jeong-Il; Madou, Marc; Shin, Heungjoo

    2013-11-20

    With the development of nanomaterial-based nanodevices, it became inevitable to develop cost-effective and simple nanofabrication technologies enabling the formation of nanomaterial assembly in a controllable manner. Herein, we present suspended monolithic carbon single nanowires and nanomeshes bridging two bulk carbon posts, fabricated in a designed manner using two successive UV exposure steps and a single pyrolysis step. The pyrolysis step is accompanied with a significant volume reduction, resulting in the shrinkage of micro-sized photoresist structures into nanoscale carbon structures. Even with the significant elongation of the suspended carbon nanowire induced by the volume reduction of the bulk carbon posts, the resultant tensional stress along the nanowire is not significant but grows along the wire thickness; this tensional stress gradient and the bent supports of the bridge-like carbon nanowire enhance structural robustness and alleviate the stiction problem that suspended nanostructures frequently experience. The feasibility of the suspended carbon nanostructures as a sensor platform was demonstrated by testing its electrochemical behavior, conductivity-temperature relationship, and hydrogen gas sensing capability.

  4. Physical properties and structure of large grain/single crystal niobium for superconducting RF cavities

    International Nuclear Information System (INIS)

    Ermakov, A; Jelezov, I; Singer, X; Singer, W; Wen, H; Spiwek, M; Viswanathan, G B; Levit, V; Fraser, H L

    2008-01-01

    The R and D program on superconducting cavities fabricated from electron beam melted large grain/single crystal (LG/SC) niobium discs explores it's potential for production of approximately 1000 cavities for the European XFEL. Thermal, electrical, mechanical properties, crystal orientation and structure are investigated with the aim to make the fabrication procedure more efficient. In opposite to fine grain niobium the thermal conductivity of LG/SC has a pronounced maximum at 2K. Calculation found a correlation between thermal conductivity enhancement and phonon scattering at the grain boundaries. Detected enhancement is very susceptible to plastic deformation that can cause the complete elimination of the low temperature peak. The final annealing at 800 deg. C of cavities made from large grain niobium is necessary for hydrogen outgassing, as well as for the thermal conductivity enhancement due to stress relaxation and recovery of crystal defects introduced at the cavity fabrication. The effects of annealing temperature up to 1200 deg. C, heating rate, and holding time on the structure recovery after rolling are also established. Total elongation at the uniaxial tensile tests for LG is very high (50-110%) and depends significantly on the load direction, because only very few grains are in the gage length. The elongation after fracture by bi-axial testing (bulging test) for LG is lower (<15%) yet sufficient for deep drawing of half-cells. Metallographic investigation of and electron beam welding tests on, niobium single crystals show that an appropriate disc enlargement and annealing can be done without destruction of the single crystal. These tests showed that a cavity can be produced without grain boundaries even in the welding area. On base of the results a fabrication method of single crystal cavities is proposed

  5. Measurements of gas filled halfraum energetics at the national ignition facility using a single quad

    International Nuclear Information System (INIS)

    Kline, J.L.; Fernandez, J.C.; Goldman, S.R.; Gautier, D.C.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.A.; Workman, J.B.; Braun, D.; Landen, O.; Niemann, C.; Campbell, K.; Celeste, J.; Dewald, E.; Glenzer, S.; Hinkel, D.; Holder, J.; Kalantar, D.; Kamperschroer, J.; Kimbrough, J.; Kirkwood, R.; Lee, F.D.; MacGowan, B.; MacKinnon, A.; McDonald, J.; Schein, J.; Schneider, M.; Suter, L.; Young, B.

    2006-01-01

    Gas filled halfraum experiments were conducted at the National Ignition Facility which provided an excellent test of the tools needed to understand halfraum energetics in an ignition relevant regime. The experiments used a highly shaped laser pulse and measured large levels of backscattered laser energy. These two components challenge the ability of radiation hydrodynamic simulations to model the experiments. The results show good agreement between experimental measurements and simulations. (authors)

  6. Single crystal growth and electronic structure of TlPbI{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Khyzhun, O.Y., E-mail: khyzhun@ipms.kiev.ua [Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanivsky Street, 03142 Kyiv (Ukraine); Fochuk, P.M. [Yuriy Fedkovich Chernivtsi National University, 2 Kotsyubynskogo Street, 58012 Chernivtsi (Ukraine); Kityk, I.V. [Faculty of Electrical Engineering, Czestochowa University of Technology, Armii Krajowej 17, PL-42-217 Czestochowa (Poland); Piasecki, M. [Institute of Physics, J.Dlugosz University Częstochowa, Armii Krajowej 13/15, Częstochowa (Poland); Levkovets, S.I. [Department of Inorganic and Physical Chemistry, Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine); Fedorchuk, A.O. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, 50 Pekarska Street, 79010 Lviv (Ukraine); Parasyuk, O.V. [Department of Inorganic and Physical Chemistry, Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine)

    2016-04-01

    High-quality inclusion-free TlPbI{sub 3} single crystals have been grown using Bridgman–Stockbarger method. The electronic structure of TlPbI{sub 3} is studied by using the possibilities of X-ray photoelectron spectroscopy (XPS). For the TlPbI{sub 3} crystal, XPS core-level and valence-band spectra for both pristine and Ar{sup +} ion-bombarded surfaces are recorded. The present XPS data indicate that the TlPbI{sub 3} single crystal surface is somewhat sensitive with respect to Ar{sup +} ion-bombardment. In particular, the XPS measurements reveal that thallium and lead atoms are in the formal valence +1 and +2, respectively, on the pristine TlPbI{sub 3} single crystal surface. Further, the 3.0 keV Ar{sup +} ion-bombardment of the surface induces partial transformation of lead ions to lower valence state, namely Pb{sup 0}; however, no partial loss of iodine atoms belonging to TlI{sub 8} polyhedra occurs due to the Ar{sup +} ion-bombardment of the TlPbI{sub 3} surface because after such a treatment thallium remains exclusively in the formal valence +1. The present XPS results indicate that low hygroscopicity is characteristic of the TlPbI{sub 3} single crystal surface. Photoinduced birefringence profiles in TlPbI{sub 3} are explored. - Highlights: • High-quality TlPbI{sub 3} single crystals have been grown by Bridgman–Stockbarger method. • Electronic structure of TlPbI{sub 3} is studied by the XPS method. • XPS data reveal low hygroscopicity of TlPbI{sub 3} surface. • TlPbI{sub 3} single crystal surface is sensitive with respect to Ar{sup +} ion-bombardment. • Photoinduced birefringence profiles in TlPbI{sub 3} are explored.

  7. Macronuclear genome structure of the ciliate Nyctotherus ovalis: Single-gene chromosomes and tiny introns

    Directory of Open Access Journals (Sweden)

    Landweber Laura F

    2008-12-01

    Full Text Available Abstract Background Nyctotherus ovalis is a single-celled eukaryote that has hydrogen-producing mitochondria and lives in the hindgut of cockroaches. Like all members of the ciliate taxon, it has two types of nuclei, a micronucleus and a macronucleus. N. ovalis generates its macronuclear chromosomes by forming polytene chromosomes that subsequently develop into macronuclear chromosomes by DNA elimination and rearrangement. Results We examined the structure of these gene-sized macronuclear chromosomes in N. ovalis. We determined the telomeres, subtelomeric regions, UTRs, coding regions and introns by sequencing a large set of macronuclear DNA sequences (4,242 and cDNAs (5,484 and comparing them with each other. The telomeres consist of repeats CCC(AAAACCCCn, similar to those in spirotrichous ciliates such as Euplotes, Sterkiella (Oxytricha and Stylonychia. Per sequenced chromosome we found evidence for either a single protein-coding gene, a single tRNA, or the complete ribosomal RNAs cluster. Hence the chromosomes appear to encode single transcripts. In the short subtelomeric regions we identified a few overrepresented motifs that could be involved in gene regulation, but there is no consensus polyadenylation site. The introns are short (21–29 nucleotides, and a significant fraction (1/3 of the tiny introns is conserved in the distantly related ciliate Paramecium tetraurelia. As has been observed in P. tetraurelia, the N. ovalis introns tend to contain in-frame stop codons or have a length that is not dividable by three. This pattern causes premature termination of mRNA translation in the event of intron retention, and potentially degradation of unspliced mRNAs by the nonsense-mediated mRNA decay pathway. Conclusion The combination of short leaders, tiny introns and single genes leads to very minimal macronuclear chromosomes. The smallest we identified contained only 150 nucleotides.

  8. Room temperature phosphorescence study on the structural flexibility of single tryptophan containing proteins

    Science.gov (United States)

    Kowalska-Baron, Agnieszka; Gałęcki, Krystian; Wysocki, Stanisław

    2015-01-01

    In this study, we have undertaken efforts to find correlation between phosphorescence lifetimes of single tryptophan containing proteins and some structural indicators of protein flexibility/rigidity, such as the degree of tryptophan burial or its exposure to solvent, protein secondary and tertiary structure of the region of localization of tryptophan as well as B factors for tryptophan residue and its immediate surroundings. Bearing in mind that, apart from effective local viscosity of the protein/solvent matrix, the other factor that concur in determining room temperature tryptophan phosphorescence (RTTP) lifetime in proteins is the extent of intramolecular quenching by His, Cys, Tyr and Trp side chains, the crystallographic structures derived from the Brookhaven Protein Data Bank were also analyzed concentrating on the presence of potentially quenching amino acid side chains in the close proximity of the indole chromophore. The obtained results indicated that, in most cases, the phosphorescence lifetimes of tryptophan containing proteins studied tend to correlate with the above mentioned structural indicators of protein rigidity/flexibility. This correlation is expected to provide guidelines for the future development of phosphorescence lifetime-based method for the prediction of structural flexibility of proteins, which is directly linked to their biological function.

  9. Atomic-scale structure of single-layer MoS2 nanoclusters

    DEFF Research Database (Denmark)

    Helveg, S.; Lauritsen, J. V.; Lægsgaard, E.

    2000-01-01

    We have studied using scanning tunneling microscopy (STM) the atomic-scale realm of molybdenum disulfide (MoS2) nanoclusters, which are of interest as a model system in hydrodesulfurization catalysis. The STM gives the first real space images of the shape and edge structure of single-layer MoS2 n...... nanoparticles synthesized on Au(lll), and establishes a new picture of the active edge sires of the nanoclusters. The results demonstrate a way to get detailed atomic-scale information on catalysts in general....

  10. Electronic structure of surface-supported bis(phthalocyaninato) terbium(III) single molecular magnets.

    Science.gov (United States)

    Vitali, Lucia; Fabris, Stefano; Conte, Adriano Mosca; Brink, Susan; Ruben, Mario; Baroni, Stefano; Kern, Klaus

    2008-10-01

    The electronic structure of isolated bis(phthalocyaninato) terbium(III) molecules, a novel single-molecular-magnet (SMM), supported on the Cu(111) surface has been characterized by density functional theory and scanning tunneling spectroscopy. These studies reveal that the interaction with the metal surface preserves both the molecular structure and the large spin magnetic moment of the metal center. The 4f electron states are not perturbed by the adsorption while a strong molecular/metal interaction can induce the suppression of the minor spin contribution delocalized over the molecular ligands. The calculations show that the inherent spin magnetic moment of the molecule is only weakly affected by the interaction with the surface and suggest that the SMM character might be preserved.

  11. Enhanced magnetostriction derived from magnetic single domain structures in cluster-assembled SmCo films

    Science.gov (United States)

    Bai, Yulong; Yang, Bo; Guo, Fei; Lu, Qingshan; Zhao, Shifeng

    2017-11-01

    Cluster-assembled SmCo alloy films were prepared by low energy cluster beam deposition. The structure, magnetic domain, magnetization, and magnetostriction of the films were characterized. It is shown that the as-prepared films are assembled in compact and uniformly distributed spherical cluster nanoparticles, most of which, after vacuum in situ annealing at 700 K, aggregated to form cluster islands. These cluster islands result in transformations from superparamagnetic states to magnetic single domain (MSD) states in the films. Such MSD structures contribute to the enhanced magnetostrictive behaviors with a saturation magnetostrictive coefficient of 160 × 10-6 in comparison to 105 × 10-6 for the as-prepared films. This work demonstrates candidate materials that could be applied in nano-electro-mechanical systems, low power information storage, and weak magnetic detecting devices.

  12. Seasonal variations of radon concentrations in single-family houses with different sub-structures

    DEFF Research Database (Denmark)

    Majborn, B.

    1992-01-01

    Seasonal variations of indoor radon concentrations have been studied in 70 single-family houses selected according to the type of sub-structure and the type of soil underneath the house. Five categories of sub-structure were included - slab-on-grade, crawl space, basement, and combinations...... of basement with slab-on-grade or crawl space. Half of the houses are located on clayey till and the other half on glaciofluvial gravel. In each house radon was measured in a living room and a bedroom, in the basement if present, and in the crawl space if present and accessible. The measurements were made...... with track detectors on a quarterly basis throughout a year. For living rooms and bedrooms the seasonal variations range from being highly significant for the slab-on-grade houses to being insignificant for the crawl space houses. For basements and crawl spaces the geometric mean radon concentrations do...

  13. Crystal structure of La2Mo2O9 single crystals doped with bismuth

    International Nuclear Information System (INIS)

    Alekseeva, O. A.; Verin, I. A.; Sorokina, N. I.; Krasil'nikova, A. E.; Voronkova, V. I.

    2010-01-01

    Precision X-ray diffraction studies of La 2-x Bi x Mo 2 O 9 (x = 0.04, 0.06, and 0.18) single crystals are performed. It is found that in the compounds doped with bismuth, analogously with the structure of the metastable β ms phase of pure La 2 Mo 2 O 9 (LM), the La, Mo1, and O1 atoms deviate from the threefold axis on which they are located in the high-temperature β phase. It is shown that bismuth atoms substitute for part of lanthanum atoms and occupy a position at the threefold axis in the neighborhood of the split lanthanum position. The implantation of bismuth atoms in the LM structure results in the return of a part of the molybdenum atoms to the position at the threefold axis. The occupancy of this position is equal to the occupancy of the bismuth atomic position.

  14. Effect of chain stiffness on the structure of single-chain polymer nanoparticles

    Science.gov (United States)

    Moreno, Angel J.; Bacova, Petra; Lo Verso, Federica; Arbe, Arantxa; Colmenero, Juan; Pomposo, José A.

    2018-01-01

    Polymeric single-chain nanoparticles (SCNPs) are soft nano-objects synthesized by purely intramolecular cross-linking of single polymer chains. By means of computer simulations, we investigate the conformational properties of SCNPs as a function of the bending stiffness of their linear polymer precursors. We investigate a broad range of characteristic ratios from the fully flexible case to those typical of bulky synthetic polymers. Increasing stiffness hinders bonding of groups separated by short contour distances and increases looping over longer distances, leading to more compact nanoparticles with a structure of highly interconnected loops. This feature is reflected in a crossover in the scaling behaviour of several structural observables. The scaling exponents change from those characteristic for Gaussian chains or rings in θ-solvents in the fully flexible limit, to values resembling fractal or ‘crumpled’ globular behaviour for very stiff SCNPs. We characterize domains in the SCNPs. These are weakly deformable regions that can be seen as disordered analogues of domains in disordered proteins. Increasing stiffness leads to bigger and less deformable domains. Surprisingly, the scaling behaviour of the domains is in all cases similar to that of Gaussian chains or rings, irrespective of the stiffness and degree of cross-linking. It is the spatial arrangement of the domains which determines the global structure of the SCNP (sparse Gaussian-like object or crumpled globule). Since intramolecular stiffness can be varied through the specific chemistry of the precursor or by introducing bulky side groups in its backbone, our results propose a new strategy to tune the global structure of SCNPs.

  15. Effect of interlayer on structure and performance of anode-supported SOFC single cells

    International Nuclear Information System (INIS)

    Eom, Tae Wook; Yang, Hae Kwang; Kim, Kyung Hwan; Yoon, Hyon Hee; Kim, Jong Sung; Park, Sang Joon

    2008-01-01

    To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57 W/cm 2 at 800 deg. C and 0.44 W/cm 2 at 700 deg. C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer

  16. Single-cell paired-end genome sequencing reveals structural variation per cell cycle

    Science.gov (United States)

    Voet, Thierry; Kumar, Parveen; Van Loo, Peter; Cooke, Susanna L.; Marshall, John; Lin, Meng-Lay; Zamani Esteki, Masoud; Van der Aa, Niels; Mateiu, Ligia; McBride, David J.; Bignell, Graham R.; McLaren, Stuart; Teague, Jon; Butler, Adam; Raine, Keiran; Stebbings, Lucy A.; Quail, Michael A.; D’Hooghe, Thomas; Moreau, Yves; Futreal, P. Andrew; Stratton, Michael R.; Vermeesch, Joris R.; Campbell, Peter J.

    2013-01-01

    The nature and pace of genome mutation is largely unknown. Because standard methods sequence DNA from populations of cells, the genetic composition of individual cells is lost, de novo mutations in cells are concealed within the bulk signal and per cell cycle mutation rates and mechanisms remain elusive. Although single-cell genome analyses could resolve these problems, such analyses are error-prone because of whole-genome amplification (WGA) artefacts and are limited in the types of DNA mutation that can be discerned. We developed methods for paired-end sequence analysis of single-cell WGA products that enable (i) detecting multiple classes of DNA mutation, (ii) distinguishing DNA copy number changes from allelic WGA-amplification artefacts by the discovery of matching aberrantly mapping read pairs among the surfeit of paired-end WGA and mapping artefacts and (iii) delineating the break points and architecture of structural variants. By applying the methods, we capture DNA copy number changes acquired over one cell cycle in breast cancer cells and in blastomeres derived from a human zygote after in vitro fertilization. Furthermore, we were able to discover and fine-map a heritable inter-chromosomal rearrangement t(1;16)(p36;p12) by sequencing a single blastomere. The methods will expedite applications in basic genome research and provide a stepping stone to novel approaches for clinical genetic diagnosis. PMID:23630320

  17. Growth, structural and magnetic characterization of Al-substituted barium hexaferrite single crystals

    International Nuclear Information System (INIS)

    Vinnik, D.A.; Zherebtsov, D.A.; Mashkovtseva, L.S.; Nemrava, S.; Bischoff, M.; Perov, N.S.; Semisalova, A.S.; Krivtsov, I.V.; Isaenko, L.I.; Mikhailov, G.G.; Niewa, R.

    2014-01-01

    Highlights: • Growth of large Al-substituted crystals BaFe 12−x Al x O 19. • Al-content controllable by flux composition. • Crystallographic site preference of Al unraveled. • Magnetic characterization depending on Al-content. - Abstract: Large single crystals of aluminum-substituted M-type barium hexaferrite BaFe 12−x Al x O 19 were obtained from carbonate flux. The Al content in the crystals can be controlled via the Al content of the flux up to x = 1.1 according to single crystal X-ray structure refinements. Al shows a distinct preference to substitute Fe on crystallographic sites with high coordination numbers by oxygen atoms, whereas no significant amounts of Al can be found on a tetrahedrally coordinated site. An increasing amount of the aluminum dopant results in a monotonous reduction of the Curie temperature from 440 to 415 °C and the saturation magnetization at room temperature from 68 to 57 emu/g for single crystal and from 61 to 53 emu/g for powder samples

  18. Retrieving 4-dimensional atmospheric boundary layer structure from surface observations and profiles over a single station

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Zhaoxia [Univ. of Utah, Salt Lake City, UT (United States)

    2015-10-06

    Most routine measurements from climate study facilities, such as the Department of Energy’s ARM SGP site, come from individual sites over a long period of time. While single-station data are very useful for many studies, it is challenging to obtain 3-dimensional spatial structures of atmospheric boundary layers that include prominent signatures of deep convection from these data. The principal objective of this project is to create realistic estimates of high-resolution (~ 1km × 1km horizontal grids) atmospheric boundary layer structure and the characteristics of precipitating convection. These characteristics include updraft and downdraft cumulus mass fluxes and cold pool properties over a region the size of a GCM grid column from analyses that assimilate surface mesonet observations of wind, temperature, and water vapor mixing ratio and available profiling data from single or multiple surface stations. The ultimate goal of the project is to enhance our understanding of the properties of mesoscale convective systems and also to improve their representation in analysis and numerical simulations. During the proposed period (09/15/2011–09/14/2014) and the no-cost extension period (09/15/2014–09/14/2015), significant accomplishments have been achieved relating to the stated goals. Efforts have been extended to various research and applications. Results have been published in professional journals and presented in related science team meetings and conferences. These are summarized in the report.

  19. Emerging fabrication techniques for 3D nano-structuring in plasmonics and single molecule studies

    Science.gov (United States)

    de Angelis, F.; Liberale, C.; Coluccio, M. L.; Cojoc, G.; di Fabrizio, E.

    2011-07-01

    The application of new methods and techniques to fields such as biology and medicine is becoming more and more demanding since the request of detailed information down to single molecules is a scientific necessity and a technical realistic possibility. In this effort a key role is played by emerging fabrication techniques. One of the hardest challenges is to incorporate the third dimension in the design and fabrication of novel devices. Significantly, this means that conventional nano-fabrication methods, intrinsically useful for planar structuring, have to be substituted or complemented with new approaches. In this paper we show how emerging techniques can be used for 3D structuring of noble metals down to nanoscale. In particular, the paper deals with electroless deposition of silver, ion and electron beam induced deposition, focused ion beam milling, and two-photon lithography. We exploited these techniques to fabricate different plasmonics nanolenses, nanoprobes and novel beads for optical tweezers. In the future these devices will be used for the manipulation and chemical investigation of single cells with sensitivity down to a few molecules in label free conditions and native environment. Although this paper is only devoted to nanofabrication, we foresee that the fields of biology and medicine will directly gain substantial advantages from this approach.

  20. Structural Studies of Silver Nanoparticles Obtained Through Single-Step Green Synthesis

    International Nuclear Information System (INIS)

    Peddi, Siva Prasad; Sadeh, Bilal Abdallah

    2015-01-01

    Green synthesis of silver Nanoparticles (AGNP's) has been the most prominent among the metallic nanoparticles for research for over a decade and half now due to both the simplicity of preparation and the applicability of biological species with extensive applications in medicine and biotechnology to reduce and trap the particles. The current article uses Eclipta Prostrata leaf extract as the biological species to cap the AGNP's through a single step process. The characterization data obtained was used for the analysis of the sample structure. The article emphasizes the disquisition of their shape and size of the lattice parameters and proposes a general scheme and a mathematical model for the analysis of their dependence. The data of the synthesized AGNP's has been used to advantage through the introduction of a structural shape factor for the crystalline nanoparticles. The properties of the structure of the AGNP's proposed and evaluated through a theoretical model was undeviating with the experimental consequences. This modus operandi gives scope for the structural studies of ultrafine particles prepared using biological methods. (paper)

  1. Single crystal X-ray structure of the artists' pigment zinc yellow

    Science.gov (United States)

    Simonsen, Kim Pilkjær; Christiansen, Marie Bitsch; Vinum, Morten Gotthold; Sanyova, Jana; Bendix, Jesper

    2017-08-01

    The artists' pigment zinc yellow is in general described as a complex potassium zinc chromate with the empirical formula 4ZnCrO4·K2O·3H2O. Even though the pigment has been in use since the second half of the 19th century also in large-scale industrial applications, the exact structure had hitherto been unknown. In this work, zinc yellow was synthesised by precipitation from an aqueous solution of zinc nitrate and potassium chromate under both neutral and basic conditions, and the products were compared with the pigment used in industrial paints. Analyses by Raman microscopy (MRS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and powder X-ray diffraction (PXRD), showed that the synthesised products and the industrial pigment were identical. Single-crystal X-ray crystallography determined the structure of zinc yellow as KZn2(CrO4)2(H2O)(OH) or as KZn2(CrO4)2(H3O2) emphasizing the μ-H3O2- moiety. Notably, the zinc yellow is isostructural to the recently structurally characterized cadmium analog and both belong to the natrochalcite structure type.

  2. Single Molecular Level Probing of Structure and Dynamics of Papain Under Denaturation.

    Science.gov (United States)

    Sengupta, Bhaswati; Chaudhury, Apala; Das, Nilimesh; Sen, Pratik

    2017-01-01

    Papain is a cysteine protease enzyme present in papaya and known to help in digesting peptide. Thus the structure and function of the active site of papain is of interest. The objective of present study is to unveil the overall structural transformation and the local structural change around the active site of papain as a function of chemical denaturant. Papain has been tagged at Cys-25 with a thiol specific fluorescence probe N-(7- dimethylamino-4-methylcoumarin-3-yl) iodoacetamide (DACIA). Guanidine hydrochloride (GnHCl) has been used as the chemical denaturant. Steady state, time-resolved, and single molecular level fluorescence techniques was applied to map the change in the local environment. It is found that papain undergoes a two-step denaturation in the presence of GnHCl. Fluorescence correlation spectroscopic (FCS) data indicate that the size (hydrodynamic diameter) of native papain is ~36.8 Å, which steadily increases to ~53 Å in the presence of 6M GnHCl. FCS study also reveals that the conformational fluctuation time of papain is 6.3 µs in its native state, which decreased to 2.7 µs in the presence of 0.75 M GnHCl. Upon further increase in GnHCl concentration the conformational fluctuation time increase monotonically till 6 M GnHCl, where the time constant is measured as 14 µs. On the other hand, the measurement of ellipticity, hence the helical structure, by circular dichroism spectroscopy is found to be incapable to capture such structural transformation. It is concluded that in the presence of small amount of GnHCl the active site of papain takes up a more compact structure (although the overall size increases) than in the native state, which has been designated as the intermediate state. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Example of a single national regulator responsible for both transport safety and security

    International Nuclear Information System (INIS)

    Karhu, P.; Lahkola, A.; Markkanen, M.; Hellstén, S.

    2016-01-01

    Safety and security in the use of nuclear energy and in the use of radiation, including the transport of nuclear and other radioactive material, share a common objective: to protect people, society, environment, and future generations from the harmful effects of ionizing radiation. Some measures for safety contribute to those for security, and vice versa, while some requirements of one conflict with those of the other. The differences in the requirements arise from the difference in the threat against which the measures are designed: accident vs. intent. A coordinated approach endeavours to take advantage of the similarities and to avoid the problems caused by the differences. One way to implement it is to have one competent authority responsible for the regulatory control of safety and security. It is the experience in Finland that this enables an efficient regulatory system. From the operators’ point of view, a one-stop shop regulatory authority ensures that requirements for safety and security are consistent. Both safety and security require the involvement of and cooperation between several authorities—regulatory, rescue, law enforcement—and operators. The approach in Finland is built on cooperation and a clear division of competences and responsibilities. One regulatory authority provides a fixed point of contact within the professional cooperation network as well as for the public. The one regulatory authority is also easily identifiable, as appropriate, as a point of contact in international cooperation in implementing nuclear and radiation safety and security. Whatever the national regulatory framework and the assignment of responsibilities between authorities, cooperation is essential in house, nationally, and internationally. (author)

  4. Interactions of DNA binding proteins with G-Quadruplex structures at the single molecule level

    Science.gov (United States)

    Ray, Sujay

    Guanine-rich nucleic acid (DNA/RNA) sequences can form non-canonical secondary structures, known as G-quadruplex (GQ). Numerous in vivo and in vitro studies have demonstrated formation of these structures in telomeric and non-telomeric regions of the genome. Telomeric GQs protect the chromosome ends whereas non-telomeric GQs either act as road blocks or recognition sites for DNA metabolic machinery. These observations suggest the significance of these structures in regulation of different metabolic processes, such as replication and repair. GQs are typically thermodynamically more stable than the corresponding Watson-Crick base pairing formed by G-rich and C-rich strands, making protein activity a crucial factor for their destabilization. Inside the cell, GQs interact with different proteins and their enzymatic activity is the determining factor for their stability. We studied interactions of several proteins with GQs to understand the underlying principles of protein-GQ interactions using single-molecule FRET and other biophysical techniques. Replication Protein-A (RPA), a single stranded DNA (ssDNA) binding protein, is known to posses GQ unfolding activity. First, we compared the thermal stability of three potentially GQ-forming DNA sequences (PQS) to their stability against RPA-mediated unfolding. One of these sequences is the human telomeric repeat and the other two, located in the promoter region of tyrosine hydroxylase gene, are highly heterogeneous sequences that better represent PQS in the genome. The thermal stability of these structures do not necessarily correlate with their stability against protein-mediated unfolding. We conclude that thermal stability is not necessarily an adequate criterion for predicting the physiological viability of GQ structures. To determine the critical structural factors that influence protein-GQ interactions we studied two groups of GQ structures that have systematically varying loop lengths and number of G-tetrad layers. We

  5. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    Science.gov (United States)

    Burek, Michael John

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rely on light confinement provided by total internal reflection or distributed Bragg reflection, both of which require refractive index contrast between the device and surrounding medium (often air). Such suspended nanostructures are typically fabricated in a heterolayer structure, comprising of device (top) and sacrificial (middle) layers supported by a substrate (bottom), using standard surface nanomachining techniques. A selective, isotropic etch is then used to remove the sacrificial layer, resulting in free-standing devices. While high-quality, crystalline, thin film heterolayer structures are readily available for silicon (as silicon-on-insulator (SOI)) or III-V semiconductors (i.e. GaAs/AlGaAs), there remains an extensive list of materials with attractive electro-optic, piezoelectric, quantum optical, and other properties for which high quality single-crystal thin film heterolayer structures are not available. These include complex metal oxides like lithium niobate (LiNbO3), silicon-based compounds such as silicon carbide (SiC), III-V nitrides including gallium nitride (GaN), and inert single-crystals such as diamond. Diamond is especially attractive for a variety of nanoscale technologies due to its exceptional physical and chemical properties, including high mechanical hardness, stiffness, and thermal conductivity. Optically, it is transparent over a wide wavelength range (from 220 nm to the far infrared), has a high refractive index (n ~ 2.4), and is host to a vast

  6. Demographic connectivity for ursid populations at wildlife crossing structures in Banff National Park.

    Science.gov (United States)

    Sawaya, Michael A; Clevenger, Anthony P; Kalinowski, Steven T

    2013-08-01

    Wildlife crossing structures are one solution to mitigating the fragmentation of wildlife populations caused by roads, but their effectiveness in providing connectivity has only been superficially evaluated. Hundreds of grizzly (Ursus arctos) and black bear (Ursus americanus) passages through under and overpasses have been recorded in Banff National Park, Alberta, Canada. However, the ability of crossing structures to allow individual and population-level movements across road networks remains unknown. In April 2006, we initiated a 3-year investigation into whether crossing structures provide demographic connectivity for grizzly and black bears in Banff National Park. We collected hair with multiple noninvasive methods to obtain genetic samples from grizzly and black bears around the Bow Valley. Our objectives were to determine the number of male and female grizzly and black bears that use crossing structures; examine spatial and temporal patterns of crossings; and estimate the proportions of grizzly and black bear populations in the Bow Valley that use crossing structures. Fifteen grizzly (7 female, 8 male) and 17 black bears (8 female, 9 male) used wildlife crossing structures. The number of individuals detected at wildlife crossing structures was highly correlated with the number of passages in space and time. Grizzly bears used open crossing structures (e.g., overpasses) more often than constricted crossings (e.g., culverts). Peak use of crossing structures for both bear species occurred in July, when high rates of foraging activity coincide with mating season. We compared the number of bears that used crossings with estimates of population abundance from a related study and determined that substantial percentages of grizzly (15.0% in 2006, 19.8% in 2008) and black bear (17.6% in 2006, 11.0% in 2008) populations used crossing structures. On the basis of our results, we concluded wildlife crossing structures provide demographic connectivity for bear populations

  7. Structural, optical and dielectric studies of lithium sulphate monohydrate single crystals

    Directory of Open Access Journals (Sweden)

    Najar F.A.

    2017-02-01

    Full Text Available Optical, dielectric, and thermal properties of lithium sulphate monohydrate crystals grown by slow evaporation method have been studied. The crystal structure was resolved by direct methods using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 0.0174. Plasma energy, Penn gap, Fermi energy and electronic polarizability of the grown crystal were calculated from single crystal XRD data. The electronic polarizability of lithium sulfate monohydrate was also calculated and compared with the theoretical data using Clausius-Mossotti equation. Optical band gap calculated from optical data for the grown crystal is 4.49 eV. Fourier Transform Infrared Spectroscopy study confirmed the presence of water in the crystal structure. The AC conductivity, dielectric constant and dielectric loss of the grown crystal were systemically investigated, showing a peak at about 130 °C which could be attributed to the water molecules in the crystal structure. The anomalous dielectric properties shown by the crystal have been correlated with its thermal behavior. The title crystal obeys Jonscher’s power law relation; σ(ω = σo+ Aωs, with temperature dependent exponent s < 1. The activation energy calculated for the material is 0.24 eV and suggests protonic conduction by hopping mechanism in addition to cationic conduction by lithium ions. The micro-indentation study was also carried out which revealed that the crystal belongs to a category of soft materials.

  8. Automatic tracking of vessel-like structures from a single starting point.

    Science.gov (United States)

    Oliveira, Dário Augusto Borges; Leal-Taixé, Laura; Feitosa, Raul Queiroz; Rosenhahn, Bodo

    2016-01-01

    The identification of vascular networks is an important topic in the medical image analysis community. While most methods focus on single vessel tracking, the few solutions that exist for tracking complete vascular networks are usually computationally intensive and require a lot of user interaction. In this paper we present a method to track full vascular networks iteratively using a single starting point. Our approach is based on a cloud of sampling points distributed over concentric spherical layers. We also proposed a vessel model and a metric of how well a sample point fits this model. Then, we implement the network tracking as a min-cost flow problem, and propose a novel optimization scheme to iteratively track the vessel structure by inherently handling bifurcations and paths. The method was tested using both synthetic and real images. On the 9 different data-sets of synthetic blood vessels, we achieved maximum accuracies of more than 98%. We further use the synthetic data-set to analyze the sensibility of our method to parameter setting, showing the robustness of the proposed algorithm. For real images, we used coronary, carotid and pulmonary data to segment vascular structures and present the visual results. Still for real images, we present numerical and visual results for networks of nerve fibers in the olfactory system. Further visual results also show the potential of our approach for identifying vascular networks topologies. The presented method delivers good results for the several different datasets tested and have potential for segmenting vessel-like structures. Also, the topology information, inherently extracted, can be used for further analysis to computed aided diagnosis and surgical planning. Finally, the method's modular aspect holds potential for problem-oriented adjustments and improvements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Anomalous behaviour of periodic domain structure in Gd-doped LiNbO{sub 3} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Palatnikov, M [Institute of Chemistry, Kola Science Centre RAS, Apatity, Murmansk Region (Russian Federation); Sidorov, N [Institute of Chemistry, Kola Science Centre RAS, Apatity, Murmansk Region (Russian Federation); Bormanis, K [Institute of Solid State Physics, University of Latvia, Riga (Latvia); Smith, P G R [University of Southampton, Optoelectronic Research Centre (United Kingdom)

    2007-12-15

    Atomic force microscopy studies of etching patterns, stability of regular domain structure, and anomalies of electrical characteristics in the 300-385 K range of a series of Gddoped lithium niobate single crystals grown under equal conditions are reported.

  10. Evaluation of the Electronic Structure of Single-Molecule Junctions Based on Current-Voltage and Thermopower Measurements: Application to C60 Single-Molecule Junction.

    Science.gov (United States)

    Komoto, Yuki; Isshiki, Yuji; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

    2017-02-16

    The electronic structure of molecular junctions has a significant impact on their transport properties. Despite the decisive role of the electronic structure, a complete characterization of the electronic structure remains a challenge. This is because there is no straightforward way of measuring electron spectroscopy for an individual molecule trapped in a nanoscale gap between two metal electrodes. Herein, a comprehensive approach to obtain a detailed description of the electronic structure in single-molecule junctions based on the analysis of current-voltage (I-V) and thermoelectric characteristics is described. It is shown that the electronic structure of the prototypical C 60 single-molecule junction can be resolved by analyzing complementary results of the I-V and thermoelectric measurement. This combined approach confirmed that the C 60 single-molecule junction was highly conductive with molecular electronic conductances of 0.033 and 0.003 G 0 and a molecular Seebeck coefficient of -12 μV K -1 . In addition, we revealed that charge transport was mediated by a LUMO whose energy level was located 0.5≈0.6 eV above the Fermi level of the Au electrode. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Determining stocks and flows of structural wood products in single family homes in the United States between 1950 and 2010

    DEFF Research Database (Denmark)

    Sianchuk, Robert A.; McFarlane, Paul N.; Ackom, Emmanuel

    2012-01-01

    The stocks and flows of six major structural wood products (SWPs)-lumber, plywood, oriented strand board [OSB], glue laminated timber, I-joists, and laminated veneer lumber (LVL)-in US single family homes were modeled from 1950 to 2010. The consumption of these products in US single family homes...

  12. Determination of surface structure of cleaved (001) USb2 single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shao-ping [Los Alamos National Laboratory; Hawley, Marilyn [Los Alamos National Laboratory; Bauer, Eric D [Los Alamos National Laboratory; Stockum, Phil B [STANFORD UNIV; Manoharan, Hari C [STANFORD UNIV

    2009-01-01

    We have achieved what we believe to be the first atomic resolution STM images for a uranium compound taken at room temperature. The a, b, and c lattice parameters in the images confirm that the USb{sub 2} crystals cleave on the (001) basal plane as expected. The a and b dimensions were equal, with the atoms arranged in a cubic pattern. Our calculations indicate a symmetric cut between Sb planes to be the most favorable cleavage plane and U atoms to be responsible for most of the DOS measured by STM. Some strange features associated with vacancies were observed in the STM win be discussed in conjunction with ab initio calculations. The purpose of this work is to demonstrate the power of scanning tunneling microscopy (STM) techniques combined with a theoretical underpinning to determine the surface atomic structure and properties of actinide materials, such as the quasi 2-dimensional uranium dipnictide USb{sub 2} single crystal, thereby contributing to the understanding of their surface structural and electronic properties. The members of this interesting UX{sub 2} (X=P, As, Sb, Bi) series of compounds display dual localized and itinerant 5f electron behavior within the same compound due to the hybridization of the 5f orbitals with the conduction band. With the exception of UO{sub 2}, which has to be studied at elevated temperature to generate enough carriers for STM imaging, STM techniques have not been applied successfully to the characterization of the surface atomic structure of any other single crystal actinide compound, to the best of our knowledge. However, STM has been used to a limited extent for the study of some cerium compounds. STM probes electronic properties at the atomic level and can directly provide information about the local density of filled and empty states (LDOS) states simultaneously. A STM topograph provides the local atomic arrangement and spacing of the atoms on the surface, local defect structures (e.g. steps, vacancies, and kink sites

  13. Monolithic-Structured Single-Layered Textile-Based Dye-Sensitized Solar Cells

    Science.gov (United States)

    Yun, Min Ju; Cha, Seung I.; Kim, Han Seong; Seo, Seon Hee; Lee, Dong Y.

    2016-10-01

    Textile-structured solar cells are frequently discussed in the literature due to their prospective applications in wearable devices and in building integrated solar cells that utilize their flexibility, mechanical robustness, and aesthetic appearance, but the current approaches for textile-based solar cells—including the preparation of fibre-type solar cells woven into textiles—face several difficulties from high friction and tension during the weaving process. This study proposes a new structural concept and fabrication process for monolithic-structured textile-based dye-sensitized solar cells that are fabricated by a process similar to the cloth-making process, including the preparation of wires and yarns that are woven for use in textiles, printed, dyed, and packaged. The fabricated single-layered textile-based dye-sensitized solar cells successfully act as solar cells in our study, even under bending conditions. By controlling the inter-weft spacing and the number of Ti wires for the photoelectrode conductor, we have found that the performance of this type of dye-sensitized solar cell was notably affected by the spacing between photoelectrodes and counter-electrodes, the exposed areas of Ti wires to photoelectrodes, and photoelectrodes’ surface morphology. We believe that this study provides a process and concept for improved textile-based solar cells that can form the basis for further research.

  14. Monolithic-Structured Single-Layered Textile-Based Dye-Sensitized Solar Cells

    Science.gov (United States)

    Yun, Min Ju; Cha, Seung I.; Kim, Han Seong; Seo, Seon Hee; Lee, Dong Y.

    2016-01-01

    Textile-structured solar cells are frequently discussed in the literature due to their prospective applications in wearable devices and in building integrated solar cells that utilize their flexibility, mechanical robustness, and aesthetic appearance, but the current approaches for textile-based solar cells—including the preparation of fibre-type solar cells woven into textiles—face several difficulties from high friction and tension during the weaving process. This study proposes a new structural concept and fabrication process for monolithic-structured textile-based dye-sensitized solar cells that are fabricated by a process similar to the cloth-making process, including the preparation of wires and yarns that are woven for use in textiles, printed, dyed, and packaged. The fabricated single-layered textile-based dye-sensitized solar cells successfully act as solar cells in our study, even under bending conditions. By controlling the inter-weft spacing and the number of Ti wires for the photoelectrode conductor, we have found that the performance of this type of dye-sensitized solar cell was notably affected by the spacing between photoelectrodes and counter-electrodes, the exposed areas of Ti wires to photoelectrodes, and photoelectrodes’ surface morphology. We believe that this study provides a process and concept for improved textile-based solar cells that can form the basis for further research. PMID:27708359

  15. Structure and composition of single Pt–Ru electrocatalyst nanoparticles supported on multiwall carbon nanotubes

    International Nuclear Information System (INIS)

    Paraguay-Delgado, Francisco; Malac, Marek; Alonso-Nuñez, Gabriel

    2014-01-01

    Individual Pt-Ru nanoparticles (NPs) supported on multiwall carbon nanotubes (MWCNTs) synthesized by microemulsion method were characterized by nano beam diffraction (NBD) and high resolution imaging in transmission electron microscopy (TEM). Comparing the TEM images and NBD to simulations provided insight into particle composition, structure and morphology in three dimensions. In particular, the NBD allowed us to detect various components of the individual NPs that would be difficult to observe otherwise. We find that the NPs contain four different components: Pt–RuO 2 , Pt–Ru, RuO 2 and metallic Pt. Often an individual NP is composed of more than one component. The most frequently encountered external morphology is close to a spherical shape and ∼3.7 nm in diameter. The collective properties of NPs’ assemblies were studied by thermogravimetry, differential thermal analysis and x-ray diffraction. The results allowed us to gain some insight into the relation of the NPs’ structure and composition with their catalytic performance, and revealed the presence of components not detectable by bulk methods. The electrocatalytic properties were evaluated by CO stripping, methanol oxidation and oxygen reduction. Bulk characterization methods miss many properties and structures present in the sample due to low volume fraction and due to overlap of reflections. Single NPs should be analyzed to obtain reliable indication of sample composition. (paper)

  16. Cross-National Prevalence of Traditional Bullying, Traditional Victimization, Cyberbullying and Cyber-Victimization: Comparing Single-Item and Multiple-Item Approaches of Measurement

    Science.gov (United States)

    Yanagida, Takuya; Gradinger, Petra; Strohmeier, Dagmar; Solomontos-Kountouri, Olga; Trip, Simona; Bora, Carmen

    2016-01-01

    Many large-scale cross-national studies rely on a single-item measurement when comparing prevalence rates of traditional bullying, traditional victimization, cyberbullying, and cyber-victimization between countries. However, the reliability and validity of single-item measurement approaches are highly problematic and might be biased. Data from…

  17. German National Proficiency Scales in Biology: Internal Structure, Relations to General Cognitive Abilities and Verbal Skills

    Science.gov (United States)

    Kampa, Nele; Köller, Olaf

    2016-01-01

    National and international large-scale assessments (LSA) have a major impact on educational systems, which raises fundamental questions about the validity of the measures regarding their internal structure and their relations to relevant covariates. Given its importance, research on the validity of instruments specifically developed for LSA is…

  18. Movements and group structure of giraffe (Giraffa camelopardalis) in Lake Manyara National Park, Tanzania.

    NARCIS (Netherlands)

    Jeugd, van der H.P.; Prins, H.H.T.

    2000-01-01

    Movements and group structure of giraffe Giraffa camelopardalis were studied in Lake Manyara National Park, northern Tanzania. The giraffe population in Manyara had increased from 60 to 85 individuals between the early 1980s and 1991. This increase may have been the result of an increase in browse

  19. Movements and group structure of giraffe (Giraffa camelopardalis) in Lake Manyara National Park, Tanzania

    NARCIS (Netherlands)

    van der Jeugd, HP; Prins, HHT

    Movements and group structure of giraffe Giraffa camelopardalis were studied in Lake Manyara National Park, northern Tanzania. The giraffe population in Manyara had increased from 60 to 85 individuals between the early 1980s and 1991. This increase may have been the result of an increase in browse

  20. Graph Structure in Three National Academic Webs: Power Laws with Anomalies.

    Science.gov (United States)

    Thelwall, Mike; Wilkinson, David

    2003-01-01

    Explains how the Web can be modeled as a mathematical graph and analyzes the graph structures of three national university publicly indexable Web sites from Australia, New Zealand, and the United Kingdom. Topics include commercial search engines and academic Web link research; method-analysis environment and data sets; and power laws. (LRW)

  1. Elastic properties of Ti-24Nb-4Zr-8Sn single crystals with bcc crystal structure

    International Nuclear Information System (INIS)

    Zhang, Y.W.; Li, S.J.; Obbard, E.G.; Wang, H.; Wang, S.C.; Hao, Y.L.; Yang, R.

    2011-01-01

    Research highlights: → The single crystals of Ti2448 alloy with the bcc crystal structure were prepared. → The elastic moduli and constants were measured by several resonant methods. → The crystal shows significant elastic asymmetry in tension and compression. → The crystal exhibits weak nonlinear elasticity with large elastic strain ∼2.5%. → The crystal has weak atomic interactions against crystal distortion to low symmetry. - Abstract: Single crystals of Ti2448 alloy (Ti-24Nb-4Zr-8Sn in wt.%) were grown successfully using an optical floating-zone furnace. Several kinds of resonant methods gave consistent Young's moduli of 27.1, 56.3 and 88.1 GPa and shear moduli of 34.8, 11.0 and 14.6 GPa for the , and oriented single crystals, and C 11 , C 12 and C 44 of 57.2, 36.1 and 35.9 GPa respectively. Uniaxial testing revealed asymmetrical elastic behaviors of the crystals: tension caused elastic softening with a large reversible strain of ∼4% and a stress plateau of ∼250 MPa, whereas compression resulted in gradual elastic stiffening with much smaller reversible strain. The crystals exhibited weak nonlinear elasticity with a large elastic strain of ∼2.5% and a high strength, approaching ∼20% and ∼30% of its ideal shear and ideal tensile strength respectively. The crystals showed linear elasticity with a small elastic strain of ∼1%. These elastic deformation characteristics have been interpreted in terms of weakened atomic interactions against crystal distortion to low crystal symmetry under external applied stresses. These results are consistent with the properties of polycrystalline Ti2448, including high strength, low elastic modulus, large recoverable strain and weak strengthening effect due to grain refinement.

  2. Structural, spectral and mechanical studies of bimetallic crystal: cadmium manganese thiocyanate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Manikandan, M.; Vijaya Prasath, G.; Mahalingam, T.; Ravi, G. [Alagappa University, Department of Physics, Karaikudi (India); Bhagavannarayan, G.; Vijayan, N. [National Physical Laboratory, Materials Characterization Division, New Delhi (India)

    2012-09-15

    A nonlinear optical bimetallic thiocyanate complex crystal, cadmium manganese thiocyanate (CMTC) has been successfully synthesized. The growth of single crystals of cadmium manganese thiocyanate has been accomplished from aqueous solution using slow evaporation method. The presence of manganese and cadmium in the synthesized material was confirmed through energy dispersive spectrum (EDS) analysis. Structural analysis was carried out using powder X-ray diffractometer (PXRD) and crystalline perfection of the grown crystals was ascertained by high-resolution X-ray diffraction (HRXRD) analysis. Fourier transform infrared (FTIR) spectrum was taken to confirm the functional groups. The transmittance spectrum of the crystal in the UV-visible region has been recorded and the cutoff wavelength has been determined. The dielectric measurements for the crystals were performed for various frequencies and temperatures. The mechanical properties were evaluated by Vickers microhardness testing, which reveals hardness and stiffness constant of the crystals. (orig.)

  3. Sizing Single Cantilever Beam Specimens for Characterizing Facesheet/Core Peel Debonding in Sandwich Structure

    Science.gov (United States)

    Ratcliffe, James G.

    2010-01-01

    This paper details part of an effort focused on the development of a standardized facesheet/core peel debonding test procedure. The purpose of the test is to characterize facesheet/core peel in sandwich structure, accomplished through the measurement of the critical strain energy release rate associated with the debonding process. The specific test method selected for the standardized test procedure utilizes a single cantilever beam (SCB) specimen configuration. The objective of the current work is to develop a method for establishing SCB specimen dimensions. This is achieved by imposing specific limitations on specimen dimensions, with the objectives of promoting a linear elastic specimen response, and simplifying the data reduction method required for computing the critical strain energy release rate associated with debonding. The sizing method is also designed to be suitable for incorporation into a standardized test protocol. Preliminary application of the resulting sizing method yields practical specimen dimensions.

  4. Synthesis, growth, structure determination and optical properties of chalcone derivative single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Karthi, S., E-mail: girijaeaswaradas@gmail.com; Girija, E. K., E-mail: girijaeaswaradas@gmail.com [Department of Physics, Periyar University, Salem - 636011 (India)

    2014-04-24

    Acquiring large nonlinear optical (NLO) efficient organic material is essential for the development of optoelectronics and photonic devices. Chalcone is the donor - Π - acceptor - Π - donor (D-Π-A-Π-D) type conjugated molecule with appreciable hyperpolarizability of potential interest in NLO applications. The addition of vinyl and electron donor groups in the chalcone molecule may enhance the second harmonic generation (SHG) efficiency. Here we report the synthesis, crystal growth and characterization of a chalcone derivative 1-(4-methylphenyl)-5-(4-methoxyphenyl)-penta-2,4-dien-1-one (MPMPP). The MPMPP crystal was grown by slow evaporation solution growth technique from acetone. The grown crystal structure was studied by single crystal X-ray diffraction. The SHG efficiency of the grown crystal was determined by Kurtz and Perry method.

  5. Proton resonance elastic scattering of $^{30}$Mg for single particle structure of $^{31}$Mg

    CERN Multimedia

    The single particle structure of $^{31}$Mg, which is located in the so-called “island of inversion”, will be studied through measuring Isobaric Analog Resonances (IARs) of bound states of $^{31}$Mg. They are located in the high excitation energy of $^{31}$Al. We are going to determine the spectroscopic factors and angular momenta of the parent states by measuring the excitation function of the proton resonance elastic scattering around 0 degrees in the laboratory frame with around 3 MeV/nucleon $^{30}$Mg beam. The present study will reveal the shell evolution around $^{32}$Mg. In addition, the spectroscopic factor of the (7/2)$^{−}$ state which was not yet determined experimentally, may allow one to study the shape coexistence in this nucleus.

  6. Single crystal X-ray structure of the artists’ pigment zinc yellow

    DEFF Research Database (Denmark)

    Simonsen, Kim Pilkjær; Christiansen, Marie Bitsch; Vinum, Morten Gotthold

    2017-01-01

    been unknown. In this work, zinc yellow was synthesised by precipitation from an aqueous solution of zinc nitrate and potassium chromate under both neutral and basic conditions, and the products were compared with the pigment used in industrial paints. Analyses by Raman microscopy (MRS), scanning...... electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and powder X-ray diffraction (PXRD), showed that the synthesised products and the industrial pigment were identical. Single-crystal X-ray crystallography......The artists’ pigment zinc yellow is in general described as a complex potassium zinc chromate with the empirical formula 4ZnCrO4·K2O·3H2O. Even though the pigment has been in use since the second half of the 19th century also in large-scale industrial applications, the exact structure had hitherto...

  7. Structure-property relationships in directionally solidified single crystal NiAl

    Science.gov (United States)

    Noebe, R. D.; Kim, J. T.; Gibala, R.

    1987-01-01

    The ordered intermetallic alloy NiAl is being considered as a potential high temperature structural material, but lack of ductility at ambient temperatures, especially in polycrystalline form, is presently a major obstacle in achieving this goal. Even general agreement of the intrinsic ductility that can be achieved in monocrystals is in dispute. In order to understand this problem, two directionally solidified ingots of NiAl which displayed known differences in ductility were characterized in sufficient detail to identify the corresponding microstructural differences. It was found that the type and size of casting defects, i.e., porosity, present in the material were the major factors in controlling ductility of NiAl single crystals and could explain the order of magnitude variance in fracture strains reported in the literature.

  8. Community structure of ground-ants: the role of single trees in a Mediterranean pastureland

    Science.gov (United States)

    Reyes-López, J.; Ruiz, N.; Fernández-Haeger, J.

    2003-09-01

    A study was carried out to determine the effect of single tree ( Quercus ilex subsp, ballota) shaded microhabitats on the community structure of ground-nesting ants in a semi-natural Mediterranean ecosystem ("dehesa"). A total of 1156 ant nests belonging to 20 species were detected in the study area, with a mean density of 10-11 nests per 100 m 2. Ground ant nests were denser under tree cover than on exposed grassland. Species richness and diversity also tended to increase in areas under tree canopies. These effects were found to be proportional to the area of tree cover up to a certain limit, beyond which the trend became negative. Species composition differed between open ground and tree-shaded microhabitats. Shade-tolerant species such as Plagiolepis pygmaea were more common near trees, whereas the seed harvester ant Messor barbarus was more common in open areas.

  9. Structural and electronic properties of a single C chain doped zigzag BN nanoribbons

    International Nuclear Information System (INIS)

    Wu, Ping; Wang, Qianwen; Cao, Gengyu; Tang, Fuling; Huang, Min

    2014-01-01

    The effects of single C-chain on the stability, structural and electronic properties of zigzag BN nanoribbons (ZBNNRs) were investigated by first-principles calculations. C-chain was expected to dope at B-edge for all the ribbon widths N z considered. The band gaps of C-chain doped N z -ZBNNR are narrower than that of perfect ZBNNR due to new localized states induced by C-chain. The band gaps of N z -ZBNNR-C(n) are direct except for the case of C-chain position n=2. Band gaps of BN nanoribbons are tunable by C-chain and its position n, which may endow the potential applications of BNNR in electronics.

  10. Quaternary ammonium compounds as structural probes of single batrachotoxin-activated Na+ channels

    Science.gov (United States)

    1991-01-01

    Quaternary ammonium (QA) blockers are well-known structural probes for studying the permeation pathway of voltage-gated K+ channels. In this study we have examined the effects of a series of n-alkyl- trimethylammonium compounds (Cn-QA) on batrachotoxin (BTX)-activated Na+ channels from skeletal muscle incorporated into planar lipid bilayers. We found that these amphipathic QA compounds (Cn-QA where n = 10-18) block single Na+ channels preferentially from the internal side with equilibrium dissociation constants (KD) in the submicromolar to micromolar range. External application of amphipathic QA compounds is far less effective, by a factor of greater than 200. The block can be described by a QA molecule binding to a single site in the Na+ channel permeation pathway. QA binding affinity is dependent on transmembrane voltage with an effective valence (delta) of approximately 0.5. QA dwell times (given as mean closed times, tau c) increase as a function of n-alkyl chain length, ranging from approximately 13 ms for C10-QA to 500 ms for C18-QA at +50 mV. The results imply that there is a large hydrophobic region within the Na+ channel pore which accepts up to 18 methylene groups of the Cn-QA cation. This hydrophobic domain may be of clinical significance since it also interacts with local anesthetics such as cocaine and mepivacaine. Finally, like BTX-activated Na+ channels in bilayers, unmodified Na+ channels in GH3 cells are also susceptible to QA block. Amphipathic QA cations elicit both tonic and use-dependent inhibitions of normal Na+ currents in a manner similar to that of local anesthetic cocaine. We conclude that amphipathic QA compounds are valuable structural probes to study the permeation pathway of both normal and BTX-activated Na+ channels. PMID:1662681

  11. Decomposing self-estimates of intelligence: structure and sex differences across 12 nations.

    Science.gov (United States)

    von Stumm, Sophie; Chamorro-Premuzic, Tomas; Furnham, Adrian

    2009-05-01

    This study examines the structure of self-estimates of intelligence (SEI) across 12 nations (Australia, Austria, Brazil, France, Iran, Israel, Malaysia, South Africa, Spain, Turkey, UK and US). Participants rated themselves on general and specific abilities from three popular models of intelligence: Gardner's multiple intelligences, Sternberg's triarchic theory of intelligence, and Goleman's emotional intelligence. The results showed that (a) laypeople across nations have similar and invariant concepts of intelligence, (b) concepts of intelligence are cross-culturally closely related to academic notions of intellectual ability and (c) sex differences in general and specific SEI favouring men are consistent across countries. Male hubris and female humility in SEI seem independent of sex differences in actual cognitive ability and national levels of masculinity-femininity. Furthermore, international mean differences in general SEI could not be attributed to discrepancies in national intelligence quotient (IQ) levels or to cultural variations.

  12. NMR structure of the single QALGGH zinc finger domain from the Arabidopsis thaliana SUPERMAN protein.

    Science.gov (United States)

    Isernia, Carla; Bucci, Enrico; Leone, Marilisa; Zaccaro, Laura; Di Lello, Paola; Digilio, Giuseppe; Esposito, Sabrina; Saviano, Michele; Di Blasio, Benedetto; Pedone, Carlo; Pedone, Paolo V; Fattorusso, Roberto

    2003-03-03

    Zinc finger domains of the classical type represent the most abundant DNA binding domains in eukaryotic transcription factors. Plant proteins contain from one to four zinc finger domains, which are characterized by high conservation of the sequence QALGGH, shown to be critical for DNA-binding activity. The Arabidopsis thaliana SUPERMAN protein, which contains a single QALGGH zinc finger, is necessary for proper spatial development of reproductive floral tissues and has been shown to specifically bind to DNA. Here, we report the synthesis and UV and NMR spectroscopic structural characterization of a 37 amino acid SUPERMAN region complexed to a Zn(2+) ion (Zn-SUP37) and present the first high-resolution structure of a classical zinc finger domain from a plant protein. The NMR structure of the SUPERMAN zinc finger domain consists of a very well-defined betabetaalpha motif, typical of all other Cys(2)-His(2) zinc fingers structurally characterized. As a consequence, the highly conserved QALGGH sequence is located at the N terminus of the alpha helix. This region of the domain of animal zinc finger proteins consists of hypervariable residues that are responsible for recognizing the DNA bases. Therefore, we propose a peculiar DNA recognition code for the QALGGH zinc finger domain that includes all or some of the amino acid residues at positions -1, 2, and 3 (numbered relative to the N terminus of the helix) and possibly others at the C-terminal end of the recognition helix. This study further confirms that the zinc finger domain, though very simple, is an extremely versatile DNA binding motif.

  13. Structural Architecture of Prothrombin in Solution Revealed by Single Molecule Spectroscopy.

    Science.gov (United States)

    Pozzi, Nicola; Bystranowska, Dominika; Zuo, Xiaobing; Di Cera, Enrico

    2016-08-26

    The coagulation factor prothrombin has a complex spatial organization of its modular assembly that comprises the N-terminal Gla domain, kringle-1, kringle-2, and the C-terminal protease domain connected by three intervening linkers. Here we use single molecule Förster resonance energy transfer to access the conformational landscape of prothrombin in solution and uncover structural features of functional significance that extend recent x-ray crystallographic analysis. Prothrombin exists in equilibrium between two alternative conformations, open and closed. The closed conformation predominates (70%) and features an unanticipated intramolecular collapse of Tyr(93) in kringle-1 onto Trp(547) in the protease domain that obliterates access to the active site and protects the zymogen from autoproteolytic conversion to thrombin. The open conformation (30%) is more susceptible to chymotrypsin digestion and autoactivation, and features a shape consistent with recent x-ray crystal structures. Small angle x-ray scattering measurements of prothrombin wild type stabilized 70% in the closed conformation and of the mutant Y93A stabilized 80% in the open conformation directly document two envelopes that differ 50 Å in length. These findings reveal important new details on the conformational plasticity of prothrombin in solution and the drastic structural difference between its alternative conformations. Prothrombin uses the intramolecular collapse of kringle-1 onto the active site in the closed form to prevent autoactivation. The open-closed equilibrium also defines a new structural framework for the mechanism of activation of prothrombin by prothrombinase. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Strain sensor based on gourd-shaped single-mode-multimode-single-mode hybrid optical fibre structure.

    Science.gov (United States)

    Tian, Ke; Farrell, Gerald; Wang, Xianfan; Yang, Wenlei; Xin, Yifan; Liang, Haidong; Lewis, Elfed; Wang, Pengfei

    2017-08-07

    A fibre-optic strain sensor based on a gourd-shaped joint multimode fibre (MMF) sandwiched between two single-mode fibres (SMFs) is described both theoretically and experimentally. The cladding layers of the two MMFs are reshaped to form a hemisphere using an electrical arc method and spliced together, yielding the required gourd shape. The gourd-shaped section forms a Fabry-Perot cavity between the ends of two adjacent but non-contacting multimode fibres' core. The effectiveness of the multimode interference based on the Fabry-Perot interferometer (FPI) formed within the multimode inter-fibre section is greatly improved resulting in an experimentally determined strain sensitivity of -2.60 pm/με over the range 0-1000 με. The sensing characteristics for temperature and humidity of this optical fibre strain sensor are also investigated.

  15. The cross-national structure of mental disorders: results from the World Mental Health Surveys.

    Science.gov (United States)

    de Jonge, Peter; Wardenaar, Klaas J; Lim, Carmen C W; Aguilar-Gaxiola, Sergio; Alonso, Jordi; Andrade, Laura Helena; Bunting, Brendan; Chatterji, Somnath; Ciutan, Marius; Gureje, Oye; Karam, Elie G; Lee, Sing; Medina-Mora, Maria Elena; Moskalewicz, Jacek; Navarro-Mateu, Fernando; Pennell, Beth-Ellen; Piazza, Marina; Posada-Villa, José; Torres, Yolanda; Kessler, Ronald C; Scott, Kate

    2017-12-19

    The patterns of comorbidity among mental disorders have led researchers to model the underlying structure of psychopathology. While studies have suggested a structure including internalizing and externalizing disorders, less is known with regard to the cross-national stability of this model. Moreover, little data are available on the placement of eating disorders, bipolar disorder and psychotic experiences (PEs) in this structure. We evaluated the structure of mental disorders with data from the World Health Organization Composite International Diagnostic Interview, including 15 lifetime mental disorders and six PEs. Respondents (n = 5478-15 499) were included from 10 high-, middle- and lower middle-income countries across the world aged 18 years or older. Confirmatory factor analyses (CFAs) were used to evaluate and compare the fit of different factor structures to the lifetime disorder data. Measurement invariance was evaluated with multigroup CFA (MG-CFA). A second-order model with internalizing and externalizing factors and fear and distress subfactors best described the structure of common mental disorders. MG-CFA showed that this model was stable across countries. Of the uncommon disorders, bipolar disorder and eating disorder were best grouped with the internalizing factor, and PEs with a separate factor. These results indicate that cross-national patterns of lifetime common mental-disorder comorbidity can be explained with a second-order underlying structure that is stable across countries and can be extended to also cover less common mental disorders.

  16. Structural qualification of the multifunctional instrument tree for installation in double-shell and 100-series single-shell tanks

    International Nuclear Information System (INIS)

    Strohlow, J.P.

    1995-12-01

    This document provides the technical basis and methodology for qualifying the multifunctional instrument tree (MIT) structure for installation in double-shell and 100-series single-shell tanks. Structural qualification for MIT installations in specific tanks are also contained in this document

  17. Load requirements for maintaining structural integrity of Hanford single-shell tanks during waste feed delivery and retrieval activities

    International Nuclear Information System (INIS)

    JULYK, L.J.

    1999-01-01

    This document provides structural load requirements and their basis for maintaining the structural integrity of the Hanford Single-Shell Tanks during waste feed delivery and retrieval activities. The requirements are based on a review of previous requirements and their basis documents as well as load histories with particular emphasis on the proposed lead transfer feed tanks for the privatized vitrification plant

  18. Load requirements for maintaining structural integrity of Hanford single-shell tanks during waste feed delivery and retrieval activities

    Energy Technology Data Exchange (ETDEWEB)

    JULYK, L.J.

    1999-09-22

    This document provides structural load requirements and their basis for maintaining the structural integrity of the Hanford Single-Shell Tanks during waste feed delivery and retrieval activities. The requirements are based on a review of previous requirements and their basis documents as well as load histories with particular emphasis on the proposed lead transfer feed tanks for the privatized vitrification plant.

  19. Single crystal preparation and x-ray structure analysis of non-peripherally alkyl-substituted phthalocyanine blends

    Science.gov (United States)

    Nakano, Chika; Ohmori, Masashi; Tohnai, Norimitsu; Fujii, Akihiko; Ozaki, Masanori

    2017-06-01

    Single crystals of non-peripherally alkyl-substituted macrocycle molecules, such as octahexylphthalocyanine (C6PcH2), octapentylphthalocyanine (C5PcH2), octahexyltetrabenzotriazaporphyrin (C6TBTAPH2), and their blends were prepared. The crystal structures of C6PcH2 and C5PcH2, which were determined by single-crystal X-ray structure analysis, were identified as monoclinic lattices, while that of C6TBTAPH2 was identified as a triclinic lattice. Despite the similarity between the crystal structures of C6PcH2 and C5PcH2, the single crystals grown from the blended solutions of C6PcH2 and C5PcH2 were based on a triclinic lattice. On the other hand, in the case of the single crystals composed of C6PcH2 and C6TBTAPH2, another type of crystal structure did not appear. The crystal structures of these single crystals are discussed by taking the differences in the alkyl-substituent length and the core structure into consideration.

  20. Studies on growth, crystal structure and characterization of novel organic nicotinium trifluoroacetate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, P.V. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Rajesh, N.P., E-mail: rajeshnp@hotmail.com [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Sundar, J. Kalyana; Natarajan, S. [Department of Physics, Madurai Kamaraj University, Madurai 625 021 (India); Vinitha, G. [Department of Physics, Crescent Engineering College, Chennai 600 048 (India)

    2011-09-15

    Highlights: {yields} Good quality crystals of nicotinium trifluoroacetate in monoclinic system were grown for first time. {yields} Nicotinium trifluoroacetate crystal exhibits third order nonlinear optical properties. {yields} The optical spectrum of nicotinium trifluoroacetate crystal reveals the wide transmission in the entire range with cutoff wavelength at 286 nm. {yields} Nicotinium trifluoroacetate is a low dielectric constant material. - Abstract: An organic material, nicotinium trifluoroacetate (NTF) was synthesized and single crystals in monoclinic system were grown from aqueous solution for the first time. Its solubility and metastable zone width were estimated. The crystal structure of NTF was analyzed to reveal the molecular arrangements and the formation of hydrogen bonds in the crystal. High-resolution X-ray diffraction rocking curve measurements were performed to analyze the structural perfection of the grown crystals. Functional groups in NTF were identified by Fourier transform infrared spectral analysis. Thermal behaviour and stability of NTF were studied by thermogravimetric and differential thermal analysis and differential scanning calorimetry. Mechanical and dielectric properties of NTF crystals were analyzed. Optical studies reveal that NTF crystals are transparent in the wavelength range 286-1100 nm. The third order nonlinear optical parameters of NTF were derived by the Z-scan technique.

  1. Structural and magnetic properties evolution study method using a single ribbon-shaped sample

    Science.gov (United States)

    Moya, Javier A.

    2017-06-01

    A new type of study is presented for magnetic and structural characterization of amorphous or nanocrystalline metallic alloys in ribbon or wire-shaped samples. A single sample is subjecting to successive steps of flash isocurrent heat treatments with increasing duration in time, followed by a rapid cooling, while magneto-electric properties evolution are scanned in situ at room temperature. When one set of isocurrent heat treatments is finished, the annealing current is increased and a new set of isocurrent treatments starts. The properties studied were the saturation magnetization and the coercive field at 50 Hz, magnetic permeability at 100 kHz and electrical resistance from where we also obtained the crystalline fraction. The method was applied on two samples of Finemet-like alloys and the results were analyzed from the perspective of current literature. With the present method it is possible to obtain a general and meticulous understanding of the structural and magnetic evolution of the samples tested, with a considerable saving of time and samples.

  2. Single Layer Bismuth Iodide: Computational Exploration of Structural, Electrical, Mechanical and Optical Properties

    Science.gov (United States)

    Ma, Fengxian; Zhou, Mei; Jiao, Yalong; Gao, Guoping; Gu, Yuantong; Bilic, Ante; Chen, Zhongfang; Du, Aijun

    2015-12-01

    Layered graphitic materials exhibit new intriguing electronic structure and the search for new types of two-dimensional (2D) monolayer is of importance for the fabrication of next generation miniature electronic and optoelectronic devices. By means of density functional theory (DFT) computations, we investigated in detail the structural, electronic, mechanical and optical properties of the single-layer bismuth iodide (BiI3) nanosheet. Monolayer BiI3 is dynamically stable as confirmed by the computed phonon spectrum. The cleavage energy (Ecl) and interlayer coupling strength of bulk BiI3 are comparable to the experimental values of graphite, which indicates that the exfoliation of BiI3 is highly feasible. The obtained stress-strain curve shows that the BiI3 nanosheet is a brittle material with a breaking strain of 13%. The BiI3 monolayer has an indirect band gap of 1.57 eV with spin orbit coupling (SOC), indicating its potential application for solar cells. Furthermore, the band gap of BiI3 monolayer can be modulated by biaxial strain. Most interestingly, interfacing electrically active graphene with monolayer BiI3 nanosheet leads to enhanced light absorption compared to that in pure monolayer BiI3 nanosheet, highlighting its great potential applications in photonics and photovoltaic solar cells.

  3. Single nucleotide polymorphism discovery in albacore and Atlantic bluefin tuna provides insights into worldwide population structure.

    Science.gov (United States)

    Albaina, A; Iriondo, M; Velado, I; Laconcha, U; Zarraonaindia, I; Arrizabalaga, H; Pardo, M A; Lutcavage, M; Grant, W S; Estonba, A

    2013-12-01

    The optimal management of the commercially important, but mostly over-exploited, pelagic tunas, albacore (Thunnus alalunga Bonn., 1788) and Atlantic bluefin tuna (BFT; Thunnus thynnus L., 1758), requires a better understanding of population structure than has been provided by previous molecular methods. Despite numerous studies of both species, their population structures remain controversial. This study reports the development of single nucleotide polymorphisms (SNPs) in albacore and BFT and the application of these SNPs to survey genetic variability across the geographic ranges of these tunas. A total of 616 SNPs were discovered in 35 albacore tuna by comparing sequences of 54 nuclear DNA fragments. A panel of 53 SNPs yielded FST values ranging from 0.0 to 0.050 between samples after genotyping 460 albacore collected throughout the distribution of this species. No significant heterogeneity was detected within oceans, but between-ocean comparisons (Atlantic, Pacific and Indian oceans along with Mediterranean Sea) were significant. Additionally, a 17-SNP panel was developed in Atlantic BFT by cross-species amplification in 107 fish. This limited number of SNPs discriminated between samples from the two major spawning areas of Atlantic BFT (FST  = 0.116). The SNP markers developed in this study can be used to genotype large numbers of fish without the need for standardizing alleles among laboratories. © 2013 The Authors, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.

  4. Vibrational and structural investigation of SOUL protein single crystals by using micro-Raman spectroscopy

    Science.gov (United States)

    Rossi, Barbara; Giarola, Marco; Mariotto, Gino; Ambrosi, Emmanuele; Monaco, Hugo L.

    2010-05-01

    Protein SOUL is a new member of the recently discovered putative heme-binding protein family called SOUL/HEBP and, to date, no structural information exists for this protein. Here, micro-Raman spectroscopy is used to study the vibrational properties of single crystals obtained from recombinant protein SOUL by means of two different optimization routes. This spectroscopic approach offers the valuable advantage of the in-situ collection of experimental data from protein crystals, placed onto a hanging-drop plate, under the same conditions used to grow the crystals. By focusing on the regions of amides I and III bands, some secondary structure characteristic features have been recognized. Moreover, some side-chain marker bands were observed in the Raman spectra of SOUL crystals and the unambiguous assignment of these peaks inferred by comparing the experimental Raman spectra of pure amino acids and their Raman intensities computed using quantum chemical calculations. Our comparative analysis allows to get a deeper understanding of the side-chain environments and of the interactions involving these specific amino acids in the two different SOUL crystals.

  5. Modification of mechanical properties of single crystal aluminum oxide by ion beam induced structural changes

    International Nuclear Information System (INIS)

    Ensinger, W.; Nowak, R.; Horino, Y.; Baba, K.

    1993-01-01

    The mechanical behaviour of ceramics is essentially determined by their surface qualities. As a surface modification technique, ion implantation provides the possibility to modify the mechanical properties of ceramics. Highly energetic ions are implanted into the near-surface region of a material and modify its composition and structure. Ions of aluminum, oxygen, nickel and tantalum were implanted into single-crystal α-aluminum oxide. Three-point bending tests showed that an increase in flexural strength of up to 30% could be obtained after implantation of aluminum and oxygen. Nickel and tantalum ion implantation increased the fracture toughness. Indentation tests with Knoop and Vickers diamonds and comparison of the lengths of the developed radial cracks showed that ion implantation leads to a reaction in cracking. The observed effects are assigned to radiation induced structural changes of the ceramic. Ion bombardment leads to radiation damage and formation of compressive stress. In case of tantalum implantation, the implanted near-surface zone becomes amorphous. These effects make the ceramic more resistant to fracture. (orig.)

  6. Correlating the structure and localized surface plasmon resonance of single silver right bipyramids.

    Science.gov (United States)

    Ringe, Emilie; Zhang, Jian; Langille, Mark R; Mirkin, Chad A; Marks, Laurence D; Van Duyne, Richard P

    2012-11-09

    Localized surface plasmon resonances (LSPRs), collective electron oscillations in metal nanoparticles, are being heavily scrutinized for applications in prototype devices and circuits, as well as for chemical and biological sensing. Both the plasmon frequency and linewidth of a LSPR are critical factors for application optimization, for which their dependence on structural factors has been qualitatively unraveled over the past decade. However, quantitative knowledge based on systematic single particle studies has only recently become available for a few particle shapes. We show here that to understand the effect of structure (both size and shape) on plasmonic properties, one must take multiple parameters into account. We have successfully done so for a large data set on silver right bipyramids. By correlating plasmon energy and linewidth with edge length and corner rounding for individual bipyramids, we have found that the corner rounding has a significant effect on the plasmon energy for particles of the same size, and thus corner rounding must be taken into account to accurately describe the dependence of a LSPR on nanoparticle size. A detailed explanation of the phenomena responsible for the observed effects and their relationship to each other is presented.

  7. A structural mechanics study of single-walled carbon nanotubes generalized from atomistic simulation.

    Science.gov (United States)

    Chen, Xi; Cao, Guoxin

    2006-02-28

    A new structural mechanics model is developed to closely duplicate the atomic configuration and behaviours of single-walled carbon nanotubes (SWCNTs). The SWCNTs are effectively represented by a space frame, where primary and secondary beams are used to bridge the nearest and next-nearest carbon atoms, to mimic energies associated with bond stretching and angle variation, respectively. The elastic properties of the frame components are generalized from molecular dynamics (MD) simulation based on an accurate ab initio force field, and numerical analyses of tension, bending, and torsion are carried out on nine different SWCNTs. The space-frame model also closely duplicates the buckling behaviours of SWCNTs in torsion and bending. In addition, by repeating the same process with continuum shell and beam models, new elastic and section parameters are fitted from the MD benchmark experiments. As an application, all three models are employed to study the thermal vibration behaviours of SWCNTs, and excellent agreements with MD analyses are found. The present analysis is a systematic structural mechanics attempt to fit SWCNT properties for several basic deformation modes and applicable to a variety of SWCNTs. The continuum models and fitted parameters may be used to effectively simulate the overall deformation behaviours of SWCNTs at much larger length- and timescales than pure MD analysis.

  8. Synthesis, Optical and Structural Properties of Copper Sulfide Nanocrystals from Single Molecule Precursors

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    2017-02-01

    Full Text Available We report the synthesis and structural studies of copper sulfide nanocrystals from copper (II dithiocarbamate single molecule precursors. The precursors were thermolysed in hexadecylamine (HDA to prepare HDA-capped CuS nanocrystals. The optical properties of the nanocrystals studied using UV–visible and photoluminescence spectroscopy showed absorption band edges at 287 nm that are blue shifted, and the photoluminescence spectra show emission curves that are red-shifted with respect to the absorption band edges. These shifts are as a result of the small crystallite sizes of the nanoparticles leading to quantum size effects. The structural studies were carried out using powder X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS, and atomic force microscopy. The XRD patterns indicates that the CuS nanocrystals are in hexagonal covellite crystalline phases with estimated particles sizes of 17.3–18.6 nm. The TEM images showed particles with almost spherical or rod shapes, with average crystallite sizes of 3–9.8 nm. SEM images showed morphology with ball-like microspheres on the surfaces, and EDS spectra confirmed the presence of CuS nanoparticles.

  9. Local Electronic Structure of a Single-Layer Porphyrin-Containing Covalent Organic Framework

    KAUST Repository

    Chen, Chen

    2017-12-20

    We have characterized the local electronic structure of a porphyrin-containing single-layer covalent organic framework (COF) exhibiting a square lattice. The COF monolayer was obtained by the deposition of 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (DMA) and 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) onto a Au(111) surface in ultrahigh vacuum followed by annealing to facilitate Schiff-base condensations between monomers. Scanning tunneling spectroscopy (STS) experiments conducted on isolated TAPP precursor molecules and the covalently linked COF networks yield similar transport (HOMO-LUMO) gaps of 1.85 ± 0.05 eV and 1.98 ± 0.04 eV, respectively. The COF orbital energy alignment, however, undergoes a significant downward shift compared to isolated TAPP molecules due to the electron-withdrawing nature of the imine bond formed during COF synthesis. Direct imaging of the COF local density of states (LDOS) via dI/dV mapping reveals that the COF HOMO and LUMO states are localized mainly on the porphyrin cores and that the HOMO displays reduced symmetry. DFT calculations reproduce the imine-induced negative shift in orbital energies and reveal that the origin of the reduced COF wave function symmetry is a saddle-like structure adopted by the porphyrin macrocycle due to its interactions with the Au(111) substrate.

  10. Single site porphyrine-like structures advantages over metals for selective electrochemical CO2 reduction

    DEFF Research Database (Denmark)

    Bagger, Alexander; Ju, Wen; Varela, Ana Sofia

    2017-01-01

    the competing Hydrogen Evolution Reaction (HER). The single metal site in a porphyrine-like structure requires an ontop site binding of hydrogen, compared to the hollow site binding of hydrogen on a metal catalyst surface. The difference in binding site structure gives a fundamental energy-shift in the scaling......Currently, no catalysts are completely selective for the electrochemical CO2 Reduction Reaction (CO2RR). Based on trends in density functional theory calculations of reaction intermediates we find that the single metal site in a porphyrine-like structure has a simple advantage of limiting...

  11. Tuning Electronic Structure of Single Layer MoS2through Defect and Interface Engineering.

    Science.gov (United States)

    Chen, Yan; Huang, Shengxi; Ji, Xiang; Adepalli, Kiran; Yin, Kedi; Ling, Xi; Wang, Xinwei; Xue, Jianmin; Dresselhaus, Mildred; Kong, Jing; Yildiz, Bilge

    2018-03-27

    Transition-metal dichalcogenides (TMDs) have emerged in recent years as a special group of two-dimensional materials and have attracted tremendous attention. Among these TMD materials, molybdenum disulfide (MoS 2 ) has shown promising applications in electronics, photonics, energy, and electrochemistry. In particular, the defects in MoS 2 play an essential role in altering the electronic, magnetic, optical, and catalytic properties of MoS 2 , presenting a useful way to engineer the performance of MoS 2 . The mechanisms by which lattice defects affect the MoS 2 properties are unsettled. In this work, we reveal systematically how lattice defects and substrate interface affect MoS 2 electronic structure. We fabricated single-layer MoS 2 by chemical vapor deposition and then transferred onto Au, single-layer graphene, hexagonal boron nitride, and CeO 2 as substrates and created defects in MoS 2 by ion irradiation. We assessed how these defects and substrates affect the electronic structure of MoS 2 by performing X-ray photoelectron spectroscopy, Raman and photoluminescence spectroscopies, and scanning tunneling microscopy/spectroscopy measurements. Molecular dynamics and first-principles based simulations allowed us to conclude the predominant lattice defects upon ion irradiation and associate those with the experimentally obtained electronic structure. We found that the substrates can tune the electronic energy levels in MoS 2 due to charge transfer at the interface. Furthermore, the reduction state of CeO 2 as an oxide substrate affects the interface charge transfer with MoS 2 . The irradiated MoS 2 had a faster hydrogen evolution kinetics compared to the as-prepared MoS 2 , demonstrating the concept of defect controlled reactivity in this phase. Our findings provide effective probes for energy band and defects in MoS 2 and show the importance of defect engineering in tuning the functionalities of MoS 2 and other TMDs in electronics, optoelectronics, and

  12. Temperature evolution of magnetic structure of HoFeO3 by single crystal neutron diffraction

    Directory of Open Access Journals (Sweden)

    T. Chatterji

    2017-04-01

    Full Text Available We have investigated the temperature evolution of the magnetic structures of HoFeO3 by single crystal neutron diffraction. The three different magnetic structures werevfound as a function of temperature for HoFeO3. In all three phases the fundamental coupling between the Fe sub-lattices remains the same and only their orientation and the degree of canting away from the ideal axial direction varies. The magnetic polarisation of the Ho sub-lattices in these two higher temperature regions, in which the major components of the Fe moment lie along x and y, is very small. The canting of the moments from the axial directions is attributed to the antisymmetric interactions allowed by the crystal symmetry. In the low temperature phase two further structural transitions are apparent in which the spontaneous magnetisation changes sign with respect to the underlying antiferromagnetic configuration. In this temperature range the antisymmetric exchange energy varies rapidly as the the Ho sub-lattices begin to order. So long as the ordered Ho moments are small the antisymmetric exchange is due only to Fe-Fe interactions, but as the degree of Ho order increases the Fe-Ho interactions take over whilst at the lowest temperatures, when the Ho moments approach saturation the Ho-Ho interactions dominate. The reversals of the spontaneous magnetisation found in this study suggest that in HoFeO3 the sums of the Fe-Fe and Ho-Ho antisymmetric interactions have the same sign as one another, but that of the Ho-Fe terms is opposite.

  13. Structural cerebral abnormalities and neurodevelopmental status in single ventricle congenital heart disease before Fontan procedure.

    Science.gov (United States)

    Knirsch, Walter; Mayer, Kristina Nadine; Scheer, Ianina; Tuura, Ruth; Schranz, Dietmar; Hahn, Andreas; Wetterling, Kristina; Beck, Ingrid; Latal, Beatrice; Reich, Bettina

    2017-04-01

    Neonates with single ventricle congenital heart disease are at risk for structural cerebral abnormalities. Little is known about the further evolution of cerebral abnormalities until Fontan procedure. Between August 2012 and July 2015, we conducted a prospective cross-sectional two centre study using cerebral magnetic resonance imaging (MRI) and neuro-developmental outcome assessed by the Bayley-III. Forty-seven children (31 male) were evaluated at a mean age of 25.9 ± 3.4 months with hypoplastic left heart syndrome (25) or other single ventricle (22). Cerebral MRI was abnormal in 17 patients (36.2%) including liquor space enlargements (10), small grey (9) and minimal white (5) matter injuries. Eight of 17 individuals had combined lesions. Median (range) cognitive composite score (CCS) (100, 65-120) and motor composite score (MCS) (97, 55-124) were comparable to the reference data, while language composite score (LCS) (97, 68-124) was significantly lower ( P  = 0.040). Liquor space enlargement was associated with poorer performance on all Bayley-III subscores (CCS: P  = 0.02; LCS: P  = 0.002; MCS: P  = 0.013). The number of re-operations [odds ratio (OR) 2.2, 95% confidence interval (CI) 1.1-4.3] ( P  = 0.03) and re-interventions (OR 2.1, 95% CI 1.1-3.8) ( P  = 0.03) was associated with a higher rate of overall MRI abnormalities. Cerebral MRI abnormalities occur in more than one third of children with single ventricle, while the neuro-developmental status is less severely affected before Fontan procedure. Liquor space enlargement is the predominant MRI finding associated with poorer neuro-developmental status, warranting further studies to determine aetiology and further evolution until school-age. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  14. Structural defect induced peak splitting in gold-copper bimetallic nanorods during growth by single particle spectroscopy.

    Science.gov (United States)

    Thota, Sravan; Chen, Shutang; Zhou, Yadong; Zhang, Yong; Zou, Shengli; Zhao, Jing

    2015-09-21

    A single particle level study of bimetallic nanoparticle growth provides valuable information that is usually hidden in ensemble measurements, helping to improve the understanding of a reaction mechanism and overcome the synthetic challenges. In this study, we use single particle spectroscopy to monitor the changes in the scattering spectra of Au-Cu alloy nanorods during growth. We found that the unique features of the single particle scattering spectra were due to atomic level geometric defects in the nanorods. Electrodynamics simulations have demonstrated that small structural defects of a few atomic layers split the scattering peaks, giving rise to higher order modes, which do not exist in defect-free rods of similar geometry. The study shows that single particle scattering technique is as sensitive as high-resolution electron microscopy in revealing atomic level structural defects.

  15. Decision of National and Provincial Highway Asphalt Pavement Structure Based on Value Engineering

    Directory of Open Access Journals (Sweden)

    Yingwei Ren

    2014-01-01

    Full Text Available It is important that decision of asphalt pavement structure requires overall considerations of the performance and financial investment. To have asphalt pavement structure fulfilling good reliability, the asphalt pavement structure decision was researched based on value engineering theory. According to the national and provincial highway investigation data in Shandong Province during the last decade, the asphalt pavement performance attenuation rules of traffic levels and asphalt layer thicknesses were developed, and then the road performance evaluation method was presented. In addition, the initial investments, the costs of road maintenance, and middle-scale repair in a period were analyzed. For the light traffic and medium traffic example, using the value engineering method, the pavement performance and costs of which thickness varies from 6 cm to 10 cm were calculated and compared. It was concluded that value engineering was an effective method in deciding the asphalt pavement structure.

  16. Description of the Structural Materials Information Center being established at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Oland, B.

    1990-01-01

    The US Nuclear Regulatory Commission has initiated a Structural aging Program at the Oak Ridge National Laboratory to identify potential structural safety issues related to continued service of nuclear power plants and to establish criteria for evaluating and resolving these issues. One of the tasks in this program focuses on the establishment of a Structural Materials Information Center where data and information on the time variation of concrete and concrete-related material properties under the influence of pertinent environmental stressors and aging factors will be collected and assembled into a database. This database will be used to assist in the prediction of potential long-term deterioration of critical structural components in nuclear power plants and to establish limits on hostile environmental exposure for these structures and materials. Materials property data and information will be collected at the Structural Materials Information Center from open literature, published references, and identifiable sources. Initially, the database will include portland cement concrete, metallic reinforcement, prestressing tendon and structural steel materials. Then, as data and information for other material systems are obtained, the database will be expanded and updated. The database will be developed and presented in two complementary formats. The Structural Materials Handbook will be published in four volumes as an expandable, hard copy handbook. The Materials Electronic Database will be developed to reflect the same information as contained in the handbook, but will be formatted for use on an IBM or IBM-compatible personal computer

  17. The structure of ethnic attitudes: the effects of target group, region, gender, and national identity.

    Science.gov (United States)

    Verkuyten, M

    1997-08-01

    The present study was an assessment of attitudes of 410 ethnically Dutch adolescents toward three ethnic minority groups living in the Netherlands. Stereotypes, symbolic beliefs, affective associations, and the evaluation of possible interactions were used to predict the global evaluation of ethnic outgroups and accounted for much of the variance in ethnic attitudes. The relative importance of the four predictors varied by target group and location. Gender differences were found in the structure of attitudes; symbolic beliefs played a greater role in the attitudes of boys, whereas emotions played a more central role in the attitudes of girls. The evaluation of Dutch identity was related to the favorability of ethnic attitudes and also to the underlying structure. Respondents with a positive national identity had less favorable ethnic attitudes, and emotions were more predictive of their attitudes, whereas symbolic beliefs were most predictive among respondents with a less positive national identity.

  18. Monitoring the vegetation structure of south-central Etosha National Park using terrestrial photographs

    Directory of Open Access Journals (Sweden)

    M.H.T. Hipondoka

    2003-12-01

    Full Text Available In 1984, a ground-based, photographic library was initiated for monitoring the vegetation dynamics in Etosha National Park. Over 400 photographic points were selected. At these points, panchromatic photographs were taken at intervals of six years. This study was undertaken to assess the applicability of this terrestrial photographic library in characterising the dynamics of the vegetation structure in south-central Etosha National Park. The methods employed include field validation, visual photograph interpretations, spatial analysis, and aggregated two-dimensional tables. Results, though patchy in nature, show that the vegetation structure at 63 % of the sites covered remained either unchanged or increased over the 15-year study period. The patchiness of the photo points can be exploited and be treated as training sites for corresponding satellite image classifications to provide continuous ground coverage results.

  19. Structures data collection for The National Map using volunteered geographic information

    Science.gov (United States)

    Poore, Barbara S.; Wolf, Eric B.; Korris, Erin M.; Walter, Jennifer L.; Matthews, Greg D.

    2012-01-01

    The U.S. Geological Survey (USGS) has historically sponsored volunteered data collection projects to enhance its topographic paper and digital map products. This report describes one phase of an ongoing project to encourage volunteers to contribute data to The National Map using online editing tools. The USGS recruited students studying geographic information systems (GIS) at the University of Colorado Denver and the University of Denver in the spring of 2011 to add data on structures - manmade features such as schools, hospitals, and libraries - to four quadrangles covering metropolitan Denver. The USGS customized a version of the online Potlatch editor created by the OpenStreetMap project and populated it with 30 structure types drawn from the Geographic Names Information System (GNIS), a USGS database of geographic features. The students corrected the location and attributes of these points and added information on structures that were missing. There were two rounds of quality control. Student volunteers reviewed each point, and an in-house review of each point by the USGS followed. Nine-hundred and thirty-eight structure points were initially downloaded from the USGS database. Editing and quality control resulted in 1,214 structure points that were subsequently added to The National Map. A post-project analysis of the data shows that after student edit and peer review, 92 percent of the points contributed by volunteers met National Map Accuracy Standards for horizontal accuracy. Lessons from this project will be applied to later phases. These include: simplifying editing tasks and the user interfaces, stressing to volunteers the importance of adding structures that are missing, and emphasizing the importance of conforming to editorial guidelines for formatting names and addresses of structures. The next phase of the project will encompass the entire State of Colorado and will allow any citizen to contribute structures data. Volunteers will benefit from this

  20. The network structure of adaptive governance - A single case study of a fish management area

    Directory of Open Access Journals (Sweden)

    Annica Charlotte Sandström

    2009-09-01

    Full Text Available The challenge of establishing adaptive management systems is a widely discussed topic in the literature on natural resource management. Adaptive management essentially focuses on achieving a governance process that is both sensitive to and has the capacity to continuously react to changes within the ecosystem being managed. The adoption of a network approach that perceives governance structures as social networks, searching for the kind of network features promoting this important feature, has been requested by researchers in the field. In particular, the possibilities associated with the application of a formal network approach, using the tools and concepts of social network analysis (SNA, have been identified as having significant potential for advancing this branch of research. This paper aims to address the relation between network structure and adaptability using an empirical approach. With the point of departure in a previously generated theoretical framework as well as related hypotheses, this paper presents a case study of a governance process within a fish management area in Sweden. The hypotheses state that, although higher levels of network density and centralisation promote the rule-forming process, the level of network heterogeneity is important for the existence and spread of ecological knowledge among the actors involved. According to the empirical results, restricted by the single-case study design, this assumption is still a well-working hypothesis. However, in order to advance our knowledge concerning these issues and test the validity of the hypotheses, more empirical work using a similar approach in multiple case study designs is needed.

  1. Protein crystal structure from non-oriented, single-axis sparse X-ray data

    Directory of Open Access Journals (Sweden)

    Jennifer L. Wierman

    2016-01-01

    Full Text Available X-ray free-electron lasers (XFELs have inspired the development of serial femtosecond crystallography (SFX as a method to solve the structure of proteins. SFX datasets are collected from a sequence of protein microcrystals injected across ultrashort X-ray pulses. The idea behind SFX is that diffraction from the intense, ultrashort X-ray pulses leaves the crystal before the crystal is obliterated by the effects of the X-ray pulse. The success of SFX at XFELs has catalyzed interest in analogous experiments at synchrotron-radiation (SR sources, where data are collected from many small crystals and the ultrashort pulses are replaced by exposure times that are kept short enough to avoid significant crystal damage. The diffraction signal from each short exposure is so `sparse' in recorded photons that the process of recording the crystal intensity is itself a reconstruction problem. Using the EMC algorithm, a successful reconstruction is demonstrated here in a sparsity regime where there are no Bragg peaks that conventionally would serve to determine the orientation of the crystal in each exposure. In this proof-of-principle experiment, a hen egg-white lysozyme (HEWL crystal rotating about a single axis was illuminated by an X-ray beam from an X-ray generator to simulate the diffraction patterns of microcrystals from synchrotron radiation. Millions of these sparse frames, typically containing only ∼200 photons per frame, were recorded using a fast-framing detector. It is shown that reconstruction of three-dimensional diffraction intensity is possible using the EMC algorithm, even with these extremely sparse frames and without knowledge of the rotation angle. Further, the reconstructed intensity can be phased and refined to solve the protein structure using traditional crystallographic software. This suggests that synchrotron-based serial crystallography of micrometre-sized crystals can be practical with the aid of the EMC algorithm even in cases

  2. Misfortunes never come singly: Structural change, multiple shocks and child malnutrition in rural Senegal.

    Science.gov (United States)

    Lazzaroni, Sara; Wagner, Natascha

    2016-12-01

    This study considers the two most pronounced shocks Senegalese subsistence farmers struggle with, namely increasing purchase prices and droughts. We assess the relationship of these self-reported shocks with child health in a multi-shock approach to account for concomitance of adverse events from the natural, biological, economic and health sphere. We employ a unique farming household panel dataset containing information on children living in poor, rural households in eight regions of Senegal in 2009 and 2011 and account for structural changes occurring between survey periods due to the large scale, national Nutrition Enhancement Program. By zooming in to the micro level we demonstrate that Senegal as a Sahelian country, mainly reliant on subsistence agriculture, is very vulnerable to climate variability and international price developments: According to our conservative estimates, the occurrence of a drought explains 25% of the pooled weight-for-age standard deviation, income losses 31%. Our multi-shock analysis reveals that the shocks are perceived as more severe in 2011 with droughts explaining up to 44% of the standard deviation of child health, increased prices up to 21%. Yet, the concomitance of droughts and increased prices after the structural change, i.e. the Nutrition Enhancement Program, indicates that the health of children experiencing both shocks in 2011 has improved. We argue that these results are driven by the increase in rural household income as theoretically outlined in the agricultural household model. Thus, adequate policy responses to shocks do not only depend on the nature but also on the concomitance of hazardous events. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Applying a structured innovation process to interventional radiology: a single-center experience.

    Science.gov (United States)

    Sista, Akhilesh K; Hwang, Gloria L; Hovsepian, David M; Sze, Daniel Y; Kuo, William T; Kothary, Nishita; Louie, John D; Yamada, Kei; Hong, Richard; Dhanani, Riaz; Brinton, Todd J; Krummel, Thomas M; Makower, Joshua; Yock, Paul G; Hofmann, Lawrence V

    2012-04-01

    To determine the feasibility and efficacy of applying an established innovation process to an active academic interventional radiology (IR) practice. The Stanford Biodesign Medical Technology Innovation Process was used as the innovation template. Over a 4-month period, seven IR faculty and four IR fellow physicians recorded observations. These observations were converted into need statements. One particular need relating to gastrostomy tubes was diligently screened and was the subject of a single formal brainstorming session. Investigators collected 82 observations, 34 by faculty and 48 by fellows. The categories that generated the most observations were enteral feeding (n = 9, 11%), biopsy (n = 8, 10%), chest tubes (n = 6, 7%), chemoembolization and radioembolization (n = 6, 7%), and biliary interventions (n = 5, 6%). The output from the screening on the gastrostomy tube need was a specification sheet that served as a guidance document for the subsequent brainstorming session. The brainstorming session produced 10 concepts under three separate categories. This formalized innovation process generated numerous observations and ultimately 10 concepts to potentially to solve a significant clinical need, suggesting that a structured process can help guide an IR practice interested in medical innovation. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

  4. X-ray irradiation-induced structural changes on Single Wall Carbon Nanotubes

    Science.gov (United States)

    Bardi, N.; Jurewicz, I.; King, A. K.; Alkhorayef, M. A.; Bradley, D.; Dalton, A. B.

    2017-11-01

    Dosimetry devices based on Carbon Nanotubes are a promising new technology. In particular using devices based on single wall Carbon Nanotubes may offer a tissue equivalent response with the possibility for device miniaturisation, high scale manufacturing and low cost. An important precursor to device fabrication requires a quantitative study of the effects of X-ray radiation on the physical and chemical properties of the individual nanotubes. In this study, we concentrate on the effects of relatively low doses, 20 cGy and 45 cGy , respectively. We use a range of characterization techniques including scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy to quantify the effects of the radiation dose on inherent properties of the nanotubes. Specifically we find that the radiation exposure results in a reduction in the sp2 nature of the nanotube bond structure. Moreover, our analysis indicates that the exposure results in nanotubes that have an increased defect density which ultimately effects the electrical properties of the nanotubes.

  5. Structure of a single whisker representation in layer 2 of mouse somatosensory cortex.

    Science.gov (United States)

    Clancy, Kelly B; Schnepel, Philipp; Rao, Antara T; Feldman, Daniel E

    2015-03-04

    Layer (L)2 is a major output of primary sensory cortex that exhibits very sparse spiking, but the structure of sensory representation in L2 is not well understood. We combined two-photon calcium imaging with deflection of many whiskers to map whisker receptive fields, characterize sparse coding, and quantitatively define the point representation in L2 of mouse somatosensory cortex. Neurons within a column-sized imaging field showed surprisingly heterogeneous, salt-and-pepper tuning to many different whiskers. Single whisker deflection elicited low-probability spikes in highly distributed, shifting neural ensembles spanning multiple cortical columns. Whisker-evoked response probability correlated strongly with spontaneous firing rate, but weakly with tuning properties, indicating a spectrum of inherent responsiveness across pyramidal cells. L2 neurons projecting to motor and secondary somatosensory cortex differed in whisker tuning and responsiveness, and carried different amounts of information about columnar whisker deflection. From these data, we derive a quantitative, fine-scale picture of the distributed point representation in L2. Copyright © 2015 the authors 0270-6474/15/353946-13$15.00/0.

  6. Single-neutron knockout from 20C and the structure of 19C

    Science.gov (United States)

    Hwang, J. W.; Kim, S.; Satou, Y.; Orr, N. A.; Kondo, Y.; Nakamura, T.; Gibelin, J.; Achouri, N. L.; Aumann, T.; Baba, H.; Delaunay, F.; Doornenbal, P.; Fukuda, N.; Inabe, N.; Isobe, T.; Kameda, D.; Kanno, D.; Kobayashi, N.; Kobayashi, T.; Kubo, T.; Leblond, S.; Lee, J.; Marqués, F. M.; Minakata, R.; Motobayashi, T.; Murai, D.; Murakami, T.; Muto, K.; Nakashima, T.; Nakatsuka, N.; Navin, A.; Nishi, S.; Ogoshi, S.; Otsu, H.; Sato, H.; Shimizu, Y.; Suzuki, H.; Takahashi, K.; Takeda, H.; Takeuchi, S.; Tanaka, R.; Togano, Y.; Tuff, A. G.; Vandebrouck, M.; Yoneda, K.

    2017-06-01

    The low-lying unbound level structure of the halo nucleus 19C has been investigated using single-neutron knockout from 20C on a carbon target at 280 MeV/nucleon. The invariant mass spectrum, derived from the momenta of the forward going beam velocity 18C fragment and neutrons, was found to be dominated by a very narrow near threshold (Erel = 0.036 (1) MeV) peak. Two less strongly populated resonance-like features were also observed at Erel = 0.84 (4) and 2.31 (3) MeV, both of which exhibit characteristics consistent with neutron p-shell hole states. Comparisons of the energies, measured cross sections and parallel momentum distributions to the results of shell-model and eikonal reaction calculations lead to spin-parity assignments of 5 /21+ and 1 /21- for the levels at Ex = 0.62 (9) and 2.89 (10) MeV with Sn = 0.58 (9) MeV. Spectroscopic factors were also deduced and found to be in reasonable accord with shell-model calculations. The valence neutron configuration of the 20C ground state is thus seen to include, in addition to the known 1s1/22 component, a significant 0d5/22 contribution. The level scheme of 19C, including significantly the 1 /21- cross-shell state, is well accounted for by the YSOX shell-model interaction developed from the monopole-based universal interaction.

  7. Field Geometric Calibration Method for Line Structured Light Sensor Using Single Circular Target

    Directory of Open Access Journals (Sweden)

    Tianfei Chen

    2017-01-01

    Full Text Available To achieve fast calibration of line structured light sensor, a geometric calibration approach based on single circular calibration target is proposed. The proposed method uses the circular points to establish linear equations, and according to the angle constraint, the camera intrinsic parameters can be calculated through optimization. Then, the light plane calibration is accomplished in two steps. Firstly, when the vanishing lines of target plane at various postures are obtained, the intersections between vanishing lines and laser stripe can be computed, and the normal vector of light plane can be calibrated via line fitting method using intersection points. After that, the distance from the origin of camera coordinate system to the light plane can be derived based on the model of perspective-three-point. The actual experimental result shows that this calibration method has high accuracy, its average measuring accuracy is 0.0451 mm, and relative error is 0.2314%. In addition, the entire calibration process has no complex operations. It is simple, convenient, and suitable for calibration on sites.

  8. A Single-Unit Design Structure and Gender Differences in the Swimming World Championships

    Directory of Open Access Journals (Sweden)

    Pushkar Svetlana

    2014-10-01

    Full Text Available Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012. For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286 showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences

  9. A single-unit design structure and gender differences in the swimming world championships.

    Science.gov (United States)

    Pushkar, Svetlana; Issurin, Vladimir B; Verbitsky, Oleg

    2014-09-29

    Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs) can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012). For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286) showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences.

  10. Tensile Characterization of Single-Walled Carbon Nanotubes with Helical Structural Defects.

    Science.gov (United States)

    Jhon, Young I; Kim, Chulki; Seo, Minah; Cho, Woon Jo; Lee, Seok; Jhon, Young Min

    2016-02-04

    Recently, evidence was presented that certain single-walled carbon nanotubes (SWNTs) possess helical defective traces, exhibiting distinct cleaved lines, yet their mechanical characterization remains a challenge. On the basis of the spiral growth model of SWNTs, here we present atomic details of helical defects and investigate how the tensile behaviors of SWNTs change with their presence using molecular dynamics simulations. SWNTs have exhibited substantially lower tensile strength and strain than theoretical results obtained from a seamless tubular structure, whose physical origin cannot be explained either by any known SWNT defects so far. We find that this long-lasting puzzle could be explained by assuming helical defects in SWNTs, exhibiting excellent agreement with experimental observation. The mechanism of this tensile process is elucidated by analyzing atomic stress distribution and evolution, and the effects of the chirality and diameter of SWNTs on this phenomenon are examined based on linear elastic fracture mechanics. This work contributes significantly to our understanding of the growth mechanism, defect hierarchies, and mechanical properties of SWNTs.

  11. Structure Based Thermostability Prediction Models for Protein Single Point Mutations with Machine Learning Tools.

    Directory of Open Access Journals (Sweden)

    Lei Jia

    Full Text Available Thermostability issue of protein point mutations is a common occurrence in protein engineering. An application which predicts the thermostability of mutants can be helpful for guiding decision making process in protein design via mutagenesis. An in silico point mutation scanning method is frequently used to find "hot spots" in proteins for focused mutagenesis. ProTherm (http://gibk26.bio.kyutech.ac.jp/jouhou/Protherm/protherm.html is a public database that consists of thousands of protein mutants' experimentally measured thermostability. Two data sets based on two differently measured thermostability properties of protein single point mutations, namely the unfolding free energy change (ddG and melting temperature change (dTm were obtained from this database. Folding free energy change calculation from Rosetta, structural information of the point mutations as well as amino acid physical properties were obtained for building thermostability prediction models with informatics modeling tools. Five supervised machine learning methods (support vector machine, random forests, artificial neural network, naïve Bayes classifier, K nearest neighbor and partial least squares regression are used for building the prediction models. Binary and ternary classifications as well as regression models were built and evaluated. Data set redundancy and balancing, the reverse mutations technique, feature selection, and comparison to other published methods were discussed. Rosetta calculated folding free energy change ranked as the most influential features in all prediction models. Other descriptors also made significant contributions to increasing the accuracy of the prediction models.

  12. Neutron beam applications - Development of single crystal structure analysis technique using the HANARO neutron four circle diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Il Hwan; Kim, Moon Jib; Kim, Jin Gyu [Chungnam National University, Taejon (Korea)

    2000-04-01

    As the four circle diffractometer (FCD) has been set up in HANARO, it has become possible to study the single crystal structures by means of the neutron diffraction. Taking account of the geometry of the FCD, a program for the control of te FCD and neutron data acquisition operating under Windows' circumstance has been accomplished. Also, a computer program which can automatically measure the diffraction intensity data has been developed. All data obtained from the FCD are processed automatically for further work and a software for the single crystal structure analyses has been prepared. A KC1 single crystal was selected as first test sample for a structure analysis had been successfully performed on the FCD using in-house developed program and accordingly their functionings with precision were confirmed. For regular single crystal diffraction experiments, the structure analyses of chrysoberyl and Zr(Y)0{sub 1.87} single crystals were performed using both neutron and X-ray diffraction methods, and the result showed that the neutron diffraction work is superior to the X-ray one from the viewpoint of certain crystallographic information obtainable only from the former one. 24 refs., 15 figs., 15 tabs. (Author)

  13. Innovative options for structuring oil and gas agreements on First Nation lands

    International Nuclear Information System (INIS)

    Wells, M.D.

    1999-01-01

    The paper is developed from two perspectives, both of which are integral to the manner in which the paper's topic is viewed: a First Nation's perspective and a legal perspective. The paper is premised on two important points. The first is that the paper is presented only from a First Nation's perspective, not from the commonly understood 'Indians, Inuit and Metis', but from what has historically been considered as an 'Indian' perspective. The second premise is that the entirety of Aboriginal Lands is not dealt with, which are commonly understood to include reserve lands and Aboriginal title lands. With one exception, the discussion is concerned with options for structuring agreements to reserve lands which are defined as 'a tract of land, the legal title of which is vested in Her Majesty, that has been set apart by Her Majesty, for the use and benefit of the land'. It is important to understand the perspective First Nations have of their land and resources. And from a legal point of view, it is also important to understand the distinction between Aboriginal title lands and Indian Reserve lands. Integral to this understanding is an appreciation of the manner in which First Nations' title arises. The failure of the current legislative scheme to adequately protect First Nation interests and provide for their greater participation is understood and appreciated by the author

  14. Treatment Recommendations for Single-Unit Crowns: Findings from The National Dental Practice-Based Research Network

    Science.gov (United States)

    McCracken, Michael S.; Louis, David R.; Litaker, Mark S.; Minyé, Helena M.; Mungia, Rahma; Gordan, Valeria V.; Marshall, Don G.; Gilbert, Gregg H.

    2016-01-01

    Background Objectives were to: (1) quantify practitioner variation in likelihood to recommend a crown; and (2) test whether certain dentist, practice, and clinical factors are significantly associated with this likelihood. Methods Dentists in the National Dental Practice-Based Research Network completed a questionnaire about indications for single-unit crowns. In four clinical scenarios, practitioners ranked their likelihood of recommending a single-unit crown. These responses were used to calculate a dentist-specific “Crown Factor” (CF; range 0–12). A higher score implies a higher likelihood to recommend a crown. Certain characteristics were tested for statistically significant associations with the CF. Results 1,777 of 2,132 eligible dentists responded (83%). Practitioners were most likely to recommend crowns for teeth that were fractured, cracked, endodontically-treated, or had a broken restoration. Practitioners overwhelmingly recommended crowns for posterior teeth treated endodontically (94%). Practice owners, Southwest practitioners, and practitioners with a balanced work load were more likely to recommend crowns, as were practitioners who use optical scanners for digital impressions. Conclusions There is substantial variation in the likelihood of recommending a crown. While consensus exists in some areas (posterior endodontic treatment), variation dominates in others (size of an existing restoration). Recommendations varied by type of practice, network region, practice busyness, patient insurance status, and use of optical scanners. Practical Implications Recommendations for crowns may be influenced by factors unrelated to tooth and patient variables. A concern for tooth fracture -- whether from endodontic treatment, fractured teeth, or large restorations -- prompted many clinicians to recommend crowns. PMID:27492046

  15. Treatment recommendations for single-unit crowns: Findings from The National Dental Practice-Based Research Network.

    Science.gov (United States)

    McCracken, Michael S; Louis, David R; Litaker, Mark S; Minyé, Helena M; Mungia, Rahma; Gordan, Valeria V; Marshall, Don G; Gilbert, Gregg H

    2016-11-01

    The objectives of this study were to quantify practitioner variation in likelihood to recommend a crown and test whether certain dentist, practice, and clinical factors are associated significantly with this likelihood. Dentists in The National Dental Practice-Based Research Network completed a questionnaire about indications for single-unit crowns. In 4 clinical scenarios, practitioners ranked their likelihood of recommending a single-unit crown. The authors used these responses to calculate a dentist-specific crown factor (range, 0-12). A higher score implied a higher likelihood of recommending a crown. The authors tested certain characteristics for statistically significant associations with the crown factor. A total of 1,777 of 2,132 eligible dentists (83%) responded. Practitioners were most likely to recommend crowns for teeth that were fractured, cracked, or endodontically treated or had a broken restoration. Practitioners overwhelmingly recommended crowns for posterior teeth treated endodontically (94%). Practice owners, practitioners in the Southwest, and practitioners with a balanced workload were more likely to recommend crowns, as were practitioners who used optical scanners for digital impressions. There is substantial variation in the likelihood of recommending a crown. Although consensus exists in some areas (posterior endodontic treatment), variation dominates in others (size of an existing restoration). Recommendations varied according to type of practice, network region, practice busyness, patient insurance status, and use of optical scanners. Recommendations for crowns may be influenced by factors unrelated to tooth and patient variables. A concern for tooth fracture-whether from endodontic treatment, fractured teeth, or large restorations-prompted many clinicians to recommend crowns. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

  16. Quasi-Static Single-Component Hybrid Simulation of a Composite Structure with Multi-Axis Control

    DEFF Research Database (Denmark)

    Høgh, J.; Waldbjørn, J.; Wittrup-Schmidt, J.

    2015-01-01

    This paper presents a quasi-static hybrid simulation performed on a single component structure. Hybrid simulation is a substructural technique, where a structure is divided into two sections: a numerical section of the main structure and a physical experiment of the remainder. In previous cases...... to evaluate the validity of the method, the results are compared to a test of the emulated structure – referred to here as the reference test. It was found that the error introduced by compliance in the load train was significant. Digital image correlation was for this reason implemented in the hybrid...

  17. Single molecule FRET data analysis procedures for FRET efficiency determination: probing the conformations of nucleic acid structures.

    Science.gov (United States)

    Krüger, Asger Christian; Birkedal, Victoria

    2013-11-01

    Single molecule FRET microscopy is an attractive technique for studying structural dynamics and conformational diversity of nucleic acid structures. Some of its strengths are that it can follow structural changes on a fast time scale and identify conformation distributions arising from dynamic or static population heterogeneity. Here, we give a description of the experiment and data analysis procedures of this method and detail what parameters are needed for FRET efficiency calculation. Using single molecule FRET data obtained on G-quadruplex DNA structures that exhibit large conformation diversity, we illustrate that the shape of the FRET distribution changes depending on what parameters are included in the data analysis procedure. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Leiomyosarcoma of the head and neck: A 17-year single institution experience and review of the National Cancer Data Base.

    Science.gov (United States)

    Workman, Alan D; Farquhar, Douglas R; Brody, Robert M; Parasher, Arjun K; Carey, Ryan M; Purkey, Michael T; Nagda, Danish A; Brooks, John S; Hartner, Lee P; Brant, Jason A; Newman, Jason G

    2018-04-01

    Leiomyosarcoma is a rare neoplasm of the head and neck. The purpose of this study was to present our single-institution case series of head and neck leiomyosarcoma and a review of cases in the National Cancer Data Base (NCDB). Patients with head and neck leiomyosarcoma at the University of Pennsylvania and in the NCDB were identified. Demographic characteristics, tumor factors, treatment paradigms, and outcomes were evaluated for prognostic significance. Nine patients with head and neck leiomyosarcoma from the institution were identified; a majority had high-grade disease and cutaneous leiomyosarcoma, with a 5-year survival rate of 50%. Two hundred fifty-nine patients with leiomyosarcoma were found in the NCDB; macroscopic positive margins and high-grade disease were associated with poor prognosis (P < .01), and positive surgical margins were related to adjuvant radiation (P < .001). Head and neck leiomyosarcoma presents at a high grade and is preferentially treated with surgery. Several demographic and tumor-specific factors are associated with outcomes and prognosis. © 2017 Wiley Periodicals, Inc.

  19. Does a public single payer system deliver integrated care? A national survey study among professional stakeholders in Denmark

    Directory of Open Access Journals (Sweden)

    Martin Strandberg-Larsen

    2008-07-01

    Full Text Available Background: Integrated health care delivery is a goal of health care systems; to date there has been limited information on the integration of medical care in practice. Purpose: To examine and compare perceptions of clinical integration and to identify associated strategic, cultural, technical and structural factors. Design and setting: A national survey addressed to: all county administrative managers (n=15; all hospital managers (n=44; and randomized selected samples of hospital department physician managers (n=200 and general practitioners (n=700 in Denmark. Results: Several initiatives have been implemented in Denmark to integrate care. Nevertheless, most physicians agree that only half of all patients experience well coordinated pathways. Clinical integration is a strategic priority at the managerial levels, but this is not visible at the functional levels. Financial incentives are not used to encourage coordination. The information communication technology to facilitate clinical integration is perceived to be inadequate. Conclusion: The scope for improvement is high due to the structural composition of the system. Increased managerial stewardship, alignment of the financial incentives, and expanded use of information communication technology to link sub-organisations will be a way to move the system forward to meet its explicit goal of providing an integrated delivery of services.

  20. The E. coli Single Protein Production (cSPP) System for Production and Structural Analysis of Membrane Proteins

    OpenAIRE

    Mao, Lili; Vaiphei, S. Thangminlal; Shimazu, Tsutomu; Schneider, William M.; Tang, Yuefeng; Mani, Rajeswari; Roth, Monica J.; Montelione, Gaetano T.; Inouye, Masayori

    2009-01-01

    At present, only 0.9% of PDB-deposited structures are of membrane proteins in spite of the fact that membrane proteins constitute approximately 30% of total proteins in most genomes from bacteria to humans. Here we address some of the major bottlenecks in the structural studies of membrane proteins and discuss the ability of the new technology, the Single-Protein Production (SPP) system, to help solve these bottlenecks.

  1. Optical microscopy techniques based on structured illumination and single-pixel detection

    OpenAIRE

    Rodríguez Jiménez, Ángel David

    2017-01-01

    In this Thesis, we explore single-pixel microscopy to design and develop proof-of-principle experiments where the single-pixel detection strategy outperforms conventional optical array detection in wide-field microscopy. The ability of the single-pixel detection strategy to generate a spatially resolved image of an object hidden by arbitrary scattering media has been recently demonstrated. Strikingly, a sensor without spatial resolution is able to retrieve a high-resolution image of a sample ...

  2. Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces

    Directory of Open Access Journals (Sweden)

    Armin Kleibert

    2011-01-01

    Full Text Available Background: Magnetic nanostructures and nanoparticles often show novel magnetic phenomena not known from the respective bulk materials. In the past, several methods to prepare such structures have been developed – ranging from wet chemistry-based to physical-based methods such as self-organization or cluster growth. The preparation method has a significant influence on the resulting properties of the generated nanostructures. Taking chemical approaches, this influence may arise from the chemical environment, reaction kinetics and the preparation route. Taking physical approaches, the thermodynamics and the kinetics of the growth mode or – when depositing preformed clusters/nanoparticles on a surface – the landing kinetics and subsequent relaxation processes have a strong impact and thus need to be considered when attempting to control magnetic and structural properties of supported clusters or nanoparticles.Results: In this contribution we focus on mass-filtered Fe nanoparticles in a size range from 4 nm to 10 nm that are generated in a cluster source and subsequently deposited onto two single crystalline substrates: fcc Ni(111/W(110 and bcc W(110. We use a combined approach of X-ray magnetic circular dichroism (XMCD, reflection high energy electron diffraction (RHEED and scanning tunneling microscopy (STM to shed light on the complex and size-dependent relation between magnetic properties, crystallographic structure, orientation and morphology. In particular XMCD reveals that Fe particles on Ni(111/W(110 have a significantly lower (higher magnetic spin (orbital moment compared to bulk iron. The reduced spin moments are attributed to the random particle orientation being confirmed by RHEED together with a competition of magnetic exchange energy at the interface and magnetic anisotropy energy in the particles. The RHEED data also show that the Fe particles on W(110 – despite of the large lattice mismatch between iron and tungsten – are

  3. Design and prototyping of self-centering optical single-mode fiber alignment structures

    International Nuclear Information System (INIS)

    Ebraert, Evert; Gao, Fei; Thienpont, Hugo; Van Erps, Jürgen; Beri, Stefano; Watté, Jan

    2016-01-01

    The European Commission’s goal of providing each European household with at least a 30 Mb s −1 Internet connection by 2020 would be facilitated by a widespread deployment of fibre-to-the-home, which would in turn be sped up by the development of connector essential components, such as high-precision alignment features. Currently, the performance of state-of-the-art physical contact optical fiber connectors is limited by the tolerance on the cladding of standard telecom-grade single-mode fiber (SMF), which is typically smaller than  ±1 μ m. We propose to overcome this limit by developing micro-spring-based self-centering alignment structures (SCAS) for SMF-connectors. We design these alignment structures with robustness and low-cost replication in mind, allowing for large-scale deployment. Both theoretical and finite element analysis (FEA) models are used to determine the optimal dimensions of the beams of which the micro-springs of the SCAS are comprised. Two topologies of the SCAS, consisting of three and four micro-springs respectively, are investigated for two materials: polysulfone (PSU) and polyetherimide (PEI). These materials hold great potential for high-performance fiber connectors while being compatible with low-cost production and with the harsh environmental operation conditions of those connectors. The theory and FEA agree well (<3% difference) for a simple micro-spring. When including a pedestal on the micro-spring (to bring it further away from the fiber) and for shorter spring lengths the agreement worsens. This is due to spring compression effects not being taken into account in our theoretical model. Prototypes are successfully fabricated using deep proton writing and subsequently characterized. The controlled insertion of an SMF in the SCAS is investigated and we determine that a force of 0.11 N is required. The fiber insertion also causes an out-of-plane deformation of the micro-springs in the SCAS of about 7 μ m, which is no

  4. Influence of the structural properties on the pseudocritical magnetic behavior of single-wall ferromagnetic nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Salazar-Enriquez, C.D. [PCM Computational Applications, Universidad Nacional de Colombia - Sede Manizales, A.A. 127 Manizales (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [PCM Computational Applications, Universidad Nacional de Colombia - Sede Manizales, A.A. 127 Manizales (Colombia); Restrepo, J. [Grupo de Magnetismo y Simulacion Gplus, Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia)

    2012-04-15

    In this work we address the influence of the crystalline structure, concretely when the system under study is formed by square or hexagonal unit cells, upon the magnetic properties and pseudocritical behavior of single-wall ferromagnetic nanotubes. We focus not only on the effect of the geometrical shape of the unit cell but also on their dimensions. The model employed is based on the Monte Carlo method, the Metropolis dynamics and a nearest neighbors classical Heisenberg Hamiltonian. Magnetization per magnetic site, magnetic susceptibility, specific heat and magnetic energy were computed. These properties were computed varying the system size, unit cell dimension and temperature. The dependence of the nearest neighbor exchange integral on the nanotubes geometrical characteristics is also discussed. Results revealed a strong influence of the system topology on the magnetic properties caused by the difference in the coordination number between square and hexagonal unit cell. Moreover, the nanotubes diameter influence on magnetic properties is only observed at very low values, when the distance between atoms is less than it, presented by the 2D sheet. On the other hand, it was concluded that the surface-related finite-size effects do not influence the magnetic nanotubes properties, contrary to the case of other nano-systems as thin films and nanoparticles among others. - Highlights: Black-Right-Pointing-Pointer Unit cell geometry has strong influence on the magnetic properties in ferromagnetic nanotubes. Black-Right-Pointing-Pointer The nanotube diameter increase produces a decrease of interaction between nearest neighbor. Black-Right-Pointing-Pointer Surface-related finite-size effects do not influence the magnetic nanotubes properties.

  5. Structure-Based Analysis of Single Nucleotide Variants in the Renin-Angiotensinogen Complex.

    Science.gov (United States)

    Brown, David K; Sheik Amamuddy, Olivier; Tastan Bishop, Özlem

    2017-06-01

    The renin-angiotensin system (RAS) plays an important role in regulating blood pressure and controlling sodium levels in the blood. Hyperactivity of this system has been linked to numerous conditions including hypertension, kidney disease, and congestive heart failure. Three classes of drugs have been developed to inhibit RAS. In this study, we provide a structure-based analysis of the effect of single nucleotide variants (SNVs) on the interaction between renin and angiotensinogen with the aim of revealing important residues and potentially damaging variants for further inhibitor design purposes. To identify SNVs that have functional and potentially damaging effects on the renin-angiotensinogen complex and to use computational approaches to investigate how SNVs might have damaging effects. A comprehensive set of all known SNVs in the renin and angiotensinogen proteins was extracted from the HUMA database. This dataset was filtered by removing synonymous and missense variants and using the VAPOR pipeline to predict which variants were likely to be deleterious. Variants in the filtered dataset were modeled into the renin-angiotensinogen complex using MODELLER and subjected to molecular dynamics simulations using GROMACS. The residue interaction networks of the resultant trajectories were analyzed using graph theory. This research identified important SNVs in the interface of RAS and showed how they might affect the function of the proteins. For instance, the mutant complex containing the variant P40L in angiotensinogen caused instability in the complex, indicating that this mutation plays an important role in disrupting the interaction between renin and angiotensinogen. The mutant complex containing the SNV A188V in renin was shown to have significantly increased fluctuation in the residue interaction networks. D104N in renin, associated with renal tubular dysgenesis, caused increased rigidity in the protein complex comparison to the wild type, which probably in turn

  6. Structure and Electronic Properties of In Situ Synthesized Single-Layer MoS2 on a Gold Surface

    DEFF Research Database (Denmark)

    Sørensen, Signe Grønborg; Füchtbauer, Henrik Gøbel; Tuxen, Anders Kyrme

    2014-01-01

    with scanning tunneling microscopy and X-ray photoelectron spectroscopy characterization of two-dimensional single-layer islands of MoS2 synthesized directly on a gold single crystal substrate. Thanks to a periodic modulation of the atom stacking induced by the lattice mismatch, we observe a structural buckling...... structure appears modified at the band gap edges. This electronic effect is further modulated by the moiré periodicity and leads to small substrate-induced electronic perturbations near the conduction band minimum in the band gap of MoS2. The results may be highly relevant in the context of nanopatterned......When transition metal sulfides such as MoS2 are present in the single-layer form, the electronic properties change in fundamental ways, enabling them to be used, e.g., in two-dimensional semiconductor electronics, optoelectronics, and light harvesting. The change is related to a subtle modification...

  7. Atomic force microscopy imaging and 3-D reconstructions of serial thin sections of a single cell and its interior structures

    International Nuclear Information System (INIS)

    Chen Yong; Cai Jiye; Zhao Tao; Wang Chenxi; Dong Shuo; Luo Shuqian; Chen, Zheng W.

    2005-01-01

    The thin sectioning has been widely applied in electron microscopy (EM), and successfully used for an in situ observation of inner ultrastructure of cells. This powerful technique has recently been extended to the research field of atomic force microscopy (AFM). However, there have been no reports describing AFM imaging of serial thin sections and three-dimensional (3-D) reconstruction of cells and their inner structures. In the present study, we used AFM to scan serial thin sections approximately 60 nm thick of a mouse embryonic stem (ES) cell, and to observe the in situ inner ultrastructure including cell membrane, cytoplasm, mitochondria, nucleus membrane, and linear chromatin. The high-magnification AFM imaging of single mitochondria clearly demonstrated the outer membrane, inner boundary membrane and cristal membrane of mitochondria in the cellular compartment. Importantly, AFM imaging on six serial thin sections of a single mouse ES cell showed that mitochondria underwent sequential changes in the number, morphology and distribution. These nanoscale images allowed us to perform 3-D surface reconstruction of interested interior structures in cells. Based on the serial in situ images, 3-D models of morphological characteristics, numbers and distributions of interior structures of the single ES cells were validated and reconstructed. Our results suggest that the combined AFM and serial-thin-section technique is useful for the nanoscale imaging and 3-D reconstruction of single cells and their inner structures. This technique may facilitate studies of proliferating and differentiating stages of stem cells or somatic cells at a nanoscale

  8. Atomic force microscopy imaging and 3-D reconstructions of serial thin sections of a single cell and its interior structures

    Science.gov (United States)

    Chen, Yong; Cai, Jiye; Zhao, Tao; Wang, Chenxi; Dong, Shuo; Luo, Shuqian; Chen, Zheng W.

    2010-01-01

    The thin sectioning has been widely applied in electron microscopy (EM), and successfully used for an in situ observation of inner ultrastructure of cells. This powerful technique has recently been extended to the research field of atomic force microscopy (AFM). However, there have been no reports describing AFM imaging of serial thin sections and three-dimensional (3-D) reconstruction of cells and their inner structures. In the present study, we used AFM to scan serial thin sections approximately 60nm thick of a mouse embryonic stem (ES) cell, and to observe the in situ inner ultrastructure including cell membrane, cytoplasm, mitochondria, nucleus membrane, and linear chromatin. The high-magnification AFM imaging of single mitochondria clearly demonstrated the outer membrane, inner boundary membrane and cristal membrane of mitochondria in the cellular compartment. Importantly, AFM imaging on six serial thin sections of a single mouse ES cell showed that mitochondria underwent sequential changes in the number, morphology and distribution. These nanoscale images allowed us to perform 3-D surface reconstruction of interested interior structures in cells. Based on the serial in situ images, 3-D models of morphological characteristics, numbers and distributions of interior structures of the single ES cells were validated and reconstructed. Our results suggest that the combined AFM and serial-thin-section technique is useful for the nanoscale imaging and 3-D reconstruction of single cells and their inner structures. This technique may facilitate studies of proliferating and differentiating stages of stem cells or somatic cells at a nanoscale. PMID:15850704

  9. Single crystal X-ray structural features of aromatic compounds having a pentafluorosulfuranyl (SF5) functional group

    Czech Academy of Sciences Publication Activity Database

    Du, J.; Hua, G.; Beier, Petr; Slawin, A. M. Z.; Woollins, J. D.

    2017-01-01

    Roč. 28, č. 3 (2017), s. 723-733 ISSN 1040-0400 Institutional support: RVO:61388963 Keywords : pentafluorosulfuranyl (SF5) group * aromatic compounds * single crystal X-ray structure * intramolecular interactions * intermolecular interactions Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 1.582, year: 2016

  10. Plasma process-induced latent damage on gate oxide - demonstrated by single-layer and multi-layer antenna structures

    NARCIS (Netherlands)

    Wang, Zhichun; Ackaert, Jan; Salm, Cora; Kuper, F.G.

    2001-01-01

    In this paper, by using both single-layer (SL) and multi-layer (ML) or stacked antenna structures, a simple experimental method is proposed to directly demonstrate the pure plasma process-induced latent damage on gate oxide without any impact of additional defects generated by normal constant

  11. Determining stocks and flows of structural wood products in single family homes in the United States between 1950 and 2010

    DEFF Research Database (Denmark)

    Sianchuk, Robert A.; McFarlane, Paul N.; Ackom, Emmanuel

    2012-01-01

    The stocks and flows of six major structural wood products (SWPs)-lumber, plywood, oriented strand board [OSB], glue laminated timber, I-joists, and laminated veneer lumber (LVL)-in US single family homes were modeled from 1950 to 2010. The consumption of these products in US single family homes......, modern SWPs, such as I-joists, LVL, and OSB, have replaced lumber and plywood products. The needs of the US single family housing industry have been met by a smaller mass of SWPs per unit area constructed. The mass of SWP present in construction wastes was influenced strongly by building cycles....... Production of construction waste peaked in 2005, when 3.31 million tonnes of SWPs were produced by 1.72 million single family housing starts. It diminished to 0.874 million tonnes of SWPs as the housing starts fell to 445,000 in 2009. In contrast, the mass of demolition wastes produced was affected...

  12. Structure and magnetism of single-phase epitaxial gamma '-Fe4N

    NARCIS (Netherlands)

    Costa-Kramer, JL; Borsa, DM; Garcia-Martin, JM; Martin-Gonzalez, MS; Boerma, DO; Briones, F

    Single phase epitaxial pure gamma(')-Fe4N films are grown on MgO (001) by molecular beam epitaxy of iron in the presence of nitrogen obtained from a radio frequency atomic source. The epitaxial, single phase nature of the films is revealed by x-ray diffraction and by the local magnetic environment

  13. A structurally based analytic model of growth and biomass dynamics in single species stands of conifers

    Science.gov (United States)

    Robin J. Tausch

    2015-01-01

    A theoretically based analytic model of plant growth in single species conifer communities based on the species fully occupying a site and fully using the site resources is introduced. Model derivations result in a single equation simultaneously describes changes over both, different site conditions (or resources available), and over time for each variable for each...

  14. The Legnaro National Laboratories and the SPES facility: nuclear structure and reactions today and tomorrow

    International Nuclear Information System (INIS)

    De Angelis, Giacomo; Fiorentini, Gianni

    2016-01-01

    There is a very long tradition of studying nuclear structure and reactions at the Legnaro National Laboratories (LNL) of the Istituto Nazionale di Fisica Nucleare (Italian Institute of Nuclear Physics). The wide expertise acquired in building and running large germanium arrays has made the laboratories one of the most advanced research centers in γ -ray spectroscopy. The ’gamma group’ has been deeply involved in all the national and international developments of the last 20 years and is currently one of the major contributors to the AGATA project, the first (together with its American counterpart GRETINA) γ -detector array based on γ -ray tracking. This line of research is expected to be strongly boosted by the coming into operation of the SPES radioactive ion beam project, currently under construction at LNL. In this report, written on the occasion of the 40th anniversary of the Nobel prize awarded to Aage Bohr, Ben R Mottelson and Leo Rainwater and particularly focused on the physics of nuclear structure, we intend to summarize the different lines of research that have guided nuclear structure and reaction research at LNL in the last decades. The results achieved have paved the way for the present SPES facility, a new laboratories infrastructure producing and accelerating radioactive ion beams of fission fragments and other isotopes. (invited comment)

  15. The Legnaro National Laboratories and the SPES facility: nuclear structure and reactions today and tomorrow

    Science.gov (United States)

    de Angelis, Giacomo; Fiorentini, Gianni

    2016-11-01

    There is a very long tradition of studying nuclear structure and reactions at the Legnaro National Laboratories (LNL) of the Istituto Nazionale di Fisica Nucleare (Italian Institute of Nuclear Physics). The wide expertise acquired in building and running large germanium arrays has made the laboratories one of the most advanced research centers in γ-ray spectroscopy. The ’gamma group’ has been deeply involved in all the national and international developments of the last 20 years and is currently one of the major contributors to the AGATA project, the first (together with its American counterpart GRETINA) γ-detector array based on γ-ray tracking. This line of research is expected to be strongly boosted by the coming into operation of the SPES radioactive ion beam project, currently under construction at LNL. In this report, written on the occasion of the 40th anniversary of the Nobel prize awarded to Aage Bohr, Ben R Mottelson and Leo Rainwater and particularly focused on the physics of nuclear structure, we intend to summarize the different lines of research that have guided nuclear structure and reaction research at LNL in the last decades. The results achieved have paved the way for the present SPES facility, a new laboratories infrastructure producing and accelerating radioactive ion beams of fission fragments and other isotopes.

  16. Structural and electronic properties of alkali-doped single-walled carbon nanotubes

    Science.gov (United States)

    Nemes, Norbert Marcel

    In this thesis, we study the properties of alkali doped single walled carbon nanotubes (SWNT). SWNT are crystallized into ropes, which display the one-dimensional electronic properties of the constituent nanotubes. Using x-ray diffraction, we show that the alkali atoms invade the channels in the triangular rope lattice and determine the structure of the doped ropes. We show that the diffraction profile of the doped SWNT is best described by a model where the alkali ions surround each tube in an ordered fashion by dilating the channels. Alkali doped SWNT exhibit colors similar to alkali doped graphite (GIC). We study their electronic structure with IR reflectivity; the alkali dopants donate their valence electron to the SWNT host, so the free carrier concentration increases, shifting the Drude-edge into the visible spectral range. This is accompanied by a large shift of the Fermi-level, so the characteristic transitions between the 1D van Hove singularities of the undoped SWNT diminish. The presence of the alkali ions around the SWNT breaks the translational symmetry and increases coupling between parallel tubes within ropes. We find that the momentum relaxation time shortens as the ropes become more three dimensional. We also find that alkali disorder contributes to the scattering. In p-type, HNO3 doped SWNT, the charge transfer is smaller; only the first subband of the semiconducting tubes gets depleted, shown by the disappearance of the first van Hove transition. This indicates a Fermi-level shift of ˜0.3 eV. The reflectivity has structure at low energy, which moves the Drude-peak to a sharp, intense peak at 0.1 eV in the optical conductivity, reminiscent of quasi-1D TTF-TCNQ. The DC conductivity also increases ˜80-fold during doping. The low temperature divergence of undoped SWNT disappears in alkali doped SWNT. However, we find that oxygen can modulate the low-T divergence. After outgassing, the divergence becomes ˜10 times stronger. We interpret the low

  17. Nuclear structure and radioactive decay resources at the US National Nuclear Data Center

    International Nuclear Information System (INIS)

    Sonzogni, A.A.; Burrows, T.W.; Pritychenko, B.; Tuli, J.K.; Winchell, D.F.

    2008-01-01

    The National Nuclear Data Center has a long tradition of evaluating nuclear structure and decay data as well as offering tools to assist in nuclear science research and applications. With these tools, users can obtain recommended values for nuclear structure and radioactive decay observables as well as links to the relevant articles. The main databases or tools are ENSDF, NSR, NuDat and the new Endf decay data library. The Evaluated Nuclear Structure Data File (ENSDF) stores recommended nuclear structure and decay data for all nuclei. ENSDF deals with properties such as: -) nuclear level energies, spin and parity, half-life and decay modes, -) nuclear radiation energy and intensity for different types, -) nuclear decay modes and their probabilities. The Nuclear Science References (NSR) is a bibliographic database containing nearly 200.000 nuclear sciences articles indexed according to content. About 4000 are added each year covering 80 journals as well as conference proceedings and laboratory reports. NuDat is a software product with 2 main goals, to present nuclear structure and decay information from ENSDF in a user-friendly way and to allow users to execute complex search operations in the wealth of data contained in ENSDF. The recently released Endf-B7.0 contains a decay data sub-library which has been derived from ENSDF. The way all these databases and tools have been offered to the public has undergone a drastic improvement due to advancements in information technology

  18. Institutional structure of the russian national innovative system: path dependence – effect

    Directory of Open Access Journals (Sweden)

    Elena V. Kamko

    2018-03-01

    Full Text Available Objective to analyze the effects of the postperestroika period of the 1990s on the existing national innovation system of Russia and to assess it the present stage of development. Methods the study used traditional methods of analysis synthesis description analogy systematization and historical approach and institutional analysis based on the categorical apparatus of institutional matrices theory. Results the article is an attempt to understand the problems of the modern national innovation system through the prism of the 1990s which became the cause of its imperfections. It is emphasized that the systemic problems of the economy in that period made innovative development impossible which led to the loss of intellectual capital of the country. The abrupt transition from a planned to a market economy without a smooth adjustment accompanied by the reduction in public spending on research led to the paralysis of innovation in the real sector of the economy and reduction of hightech industries. The negative influence was also produced by privatization destruction of production chains due to the collapse of the Soviet Union as well as domestic structural adjustment of the postSoviet economies. In this regard the authors investigated the peculiarities of the Russian innovation system from the standpoint of institutional approach including the problems of staff and investment resources deficit and the historical dominance of the state in the organization of scientific research. Activity of the state is studied on the basis of the Russian venture capital analysis. The conclusions are formulated about the centralization of the institutional structure of scientific research and development. The possible directions of the national innovation system improvement with a view to achieve more effective results are specified. nbsp Scientific novelty the diagnostics of the problems of modern national innovation system is made in the context of institutional

  19. The structure of an entry in the National corpus of Tuvan language

    Directory of Open Access Journals (Sweden)

    Mengi V. Ondar

    2016-12-01

    Full Text Available Contemporary information technologies and mathematical modelling has made creating corpora of natural languages significantly easier. A corpus is an information and reference system based on a collection of digitally processed texts. A corpus includes various written and oral texts in the given language, a set of dictionaries and markup – information on the properties of the text. It is the presence of the markup which distinguishes a corpus from an electronic library. At the moment, national corpora are being set up for many languages of the Russian Federation, including those of the Turkic peoples. Faculty members, postgraduate and undergraduate students at Tuvan State University and Siberian Federal University are working on the National corpus of Tuvan language. This article describes the structure of a dictionary entry in the National corpus of Tuvan language. The corpus database comprises the following tables: MAIN – the headword table, RUS, ENG, GER — translations of the headword into three languages, MORPHOLOGY — the table containing morphological data on the headword. The database is built in Microsoft Office Access. Working with the corpus dictionary includes the following functions: adding, editing and removing an entry, entry search (with transcription, setting and visualizing morphological features of a headword. The project allows us to view the corpus dictionary as a multi-structure entity with a complex hierarchical structure and a dictionary entry as its key component. The corpus dictionary we developed can be used for studying Tuvan language in its pronunciation, orthography and word analysis, as well as for searching for words and collocations in the texts included into the corpus.

  20. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Mo, M. Z., E-mail: mmo09@slac.stanford.edu; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; Makasyuk, I.; Edstrom, S.; McCormick, D.; Jobe, K.; Hast, C.; Glenzer, S. H.; Wang, X. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Sokolowski-Tinten, K. [Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, D-47048 Duisburg (Germany)

    2016-11-15

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.

  1. Dependence of the structure of ion-modified NiTi single crystal layers on the orientation of irradiated surface

    Science.gov (United States)

    Poletika, T. M.; Meisner, L. L.; Girsova, S. L.; Tverdokhlebova, A. V.; Meisner, S. N.

    2017-07-01

    The composition and structure of Si layers implanted into titanium nickelide single crystals with different orientations relative to the ion beam propagation direction have been studied using Auger electron spectroscopy and transmission electron microscopy. The role of the "soft" [111]B2 and "hard" [001]B2 NiTi orientations in the formation of the structure of ion-modified surface layer, as well as the defect structure of the surface layers of the single crystals, has been revealed. Orientation effects of selective sputtering and channeling of ions, which control the composition and thickness of the oxide and amorphous layers being formed, ion and impurity penetration depth, as well as the concentration profile of the Ni distribution over the surface, have been detected.

  2. Visible near-infrared light scattering of single silver split-ring structure made by nanosphere lithography.

    Science.gov (United States)

    Okamoto, Toshihiro; Fukuta, Tetsuya; Sato, Shuji; Haraguchi, Masanobu; Fukui, Masuo

    2011-04-11

    We succeeded in making a silver split-ring (SR) structure of approximately 130 nm in diameter on a glass substrate using a nanosphere lithography technique. The light scattering spectrum in visible near-infrared region of a single, isolated SR was measured using a microscope spectroscopy optical system. The electromagnetic field enhancement spectrum and distribution of the SR structure were simulated by the finite-difference time-domain method, and the excitation modes were clarified. The long wavelength peak in the light scattering spectra corresponded to a fundamental LC resonance mode excited by an incident electric field. It was shown that a single SR structure fabricated as abovementioned can operate as a resonator and generate a magnetic dipole. © 2011 Optical Society of America

  3. Regio-Regular Oligo and Poly(3-hexyl thiophene): Precise Structural Markers from the Vibrational Spectra of Oligomer Single Crystals.

    KAUST Repository

    Brambilla, Luigi

    2014-10-14

    © 2014 American Chemical Society. In this work, we report a comparative analysis of the infrared and Raman spectra of octa(3-hexylthiophene) (3HT)8, trideca(3-hexylthiophene) (3HT)13, and poly(3-hexylthiophene) P3HT recorded in various phases, namely, amorphous, semicrystalline, polycrystalline and single crystal. We have based our analysis on the spectra of the (3HT)8 single crystal (whose structure has been determined by selected area electron diffraction) taken as reference and on the results of DFT calculations and molecular vibrational dynamics. New and precise spectroscopic markers of the molecular structures show the existence of three phases, namely: hairy (phase 1), ordered (phase 2), and disordered/amorphous (phase 3). Conceptually, the identified markers can be used for the molecular structure analysis of other similar systems.

  4. Religious violence: Implications for nation building | Mgbachu ...

    African Journals Online (AJOL)

    Religious violence in Nigeria has devaluated our national economy. Any interested observer of the Nigeria socio-political structure is all too easily aware of the multiplicity of voices and the diversity of cultures within the one nation. Nigeria has one of the highest ethnic nationalities to be found in one single nation in the ...

  5. National Cases combining promotion scheme, ownership structure and operational strategy for Denmark, France and Portugal

    DEFF Research Database (Denmark)

    Costa, Ana; Kroff, Pablo; Morthorst, Poul Erik

    2011-01-01

    by means of energy systems analysis and studies on central cases for each of the participating project partners. This document comprises results from Work Package 6 – National Cases combining support schemes, ownership structures and operational strategies of the FC4Home research project. It integrates......The scope of the FC4Home project is to assess technical and economic aspects of the ongoing fuel cell based micro-combined heat and power demonstration projects by addressing the socio-economic and systems analyses perspectives of a large-scale promotion scheme of fuel cells. This was carried out...

  6. Automatic Knowledge Extraction and Knowledge Structuring for a National Term Bank

    DEFF Research Database (Denmark)

    Lassen, Tine; Madsen, Bodil Nistrup; Erdman Thomsen, Hanne

    2011-01-01

    This paper gives an introduction to the plans and ongoing work in a project, the aim of which is to develop methods for automatic knowledge extraction and automatic construction and updating of ontologies. The project also aims at developing methods for automatic merging of terminological data fr...... various existing sources, as well as methods for target group oriented knowledge dissemination. In this paper, we mainly focus on the plans for automatic knowledge extraction and knowledge structuring that will result in ontologies for a national term bank....

  7. A single frequency component-based re-estimated MUSIC algorithm for impact localization on complex composite structures

    International Nuclear Information System (INIS)

    Yuan, Shenfang; Bao, Qiao; Qiu, Lei; Zhong, Yongteng

    2015-01-01

    The growing use of composite materials on aircraft structures has attracted much attention for impact monitoring as a kind of structural health monitoring (SHM) method. Multiple signal classification (MUSIC)-based monitoring technology is a promising method because of its directional scanning ability and easy arrangement of the sensor array. However, for applications on real complex structures, some challenges still exist. The impact-induced elastic waves usually exhibit a wide-band performance, giving rise to the difficulty in obtaining the phase velocity directly. In addition, composite structures usually have obvious anisotropy, and the complex structural style of real aircrafts further enhances this performance, which greatly reduces the localization precision of the MUSIC-based method. To improve the MUSIC-based impact monitoring method, this paper first analyzes and demonstrates the influence of measurement precision of the phase velocity on the localization results of the MUSIC impact localization method. In order to improve the accuracy of the phase velocity measurement, a single frequency component extraction method is presented. Additionally, a single frequency component-based re-estimated MUSIC (SFCBR-MUSIC) algorithm is proposed to reduce the localization error caused by the anisotropy of the complex composite structure. The proposed method is verified on a real composite aircraft wing box, which has T-stiffeners and screw holes. Three typical categories of 41 impacts are monitored. Experimental results show that the SFCBR-MUSIC algorithm can localize impact on complex composite structures with an obviously improved accuracy. (paper)

  8. A single frequency component-based re-estimated MUSIC algorithm for impact localization on complex composite structures

    Science.gov (United States)

    Yuan, Shenfang; Bao, Qiao; Qiu, Lei; Zhong, Yongteng

    2015-10-01

    The growing use of composite materials on aircraft structures has attracted much attention for impact monitoring as a kind of structural health monitoring (SHM) method. Multiple signal classification (MUSIC)-based monitoring technology is a promising method because of its directional scanning ability and easy arrangement of the sensor array. However, for applications on real complex structures, some challenges still exist. The impact-induced elastic waves usually exhibit a wide-band performance, giving rise to the difficulty in obtaining the phase velocity directly. In addition, composite structures usually have obvious anisotropy, and the complex structural style of real aircrafts further enhances this performance, which greatly reduces the localization precision of the MUSIC-based method. To improve the MUSIC-based impact monitoring method, this paper first analyzes and demonstrates the influence of measurement precision of the phase velocity on the localization results of the MUSIC impact localization method. In order to improve the accuracy of the phase velocity measurement, a single frequency component extraction method is presented. Additionally, a single frequency component-based re-estimated MUSIC (SFCBR-MUSIC) algorithm is proposed to reduce the localization error caused by the anisotropy of the complex composite structure. The proposed method is verified on a real composite aircraft wing box, which has T-stiffeners and screw holes. Three typical categories of 41 impacts are monitored. Experimental results show that the SFCBR-MUSIC algorithm can localize impact on complex composite structures with an obviously improved accuracy.

  9. 78 FR 56906 - Announcement of the Award of Three Single-Source Program Expansion Supplement Grants to National...

    Science.gov (United States)

    2013-09-16

    ... Supplement Grants to National Human Trafficking Victim Assistance Program Grantees AGENCY: Office of Refugee.... Email: [email protected] . SUPPLEMENTARY INFORMATION: The National Human Trafficking Victim... DEPARTMENT OF HEALTH AND HUMAN SERVICES Administration for Children and Families Office of Refugee...

  10. Growth, structure and magnetic properties of single crystalline Fe/CoO/Ag(001) bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Abrudan, R.M.

    2007-07-16

    The structural and magnetic properties of epitaxially deposited single-crystalline CoO layers and Fe/CoO bilayers on Ag(001) were investigated. CoO films on Ag(001) exhibit (1 x 1) Low Energy Electron Diffraction (LEED) patterns similar to the clean Ag(001) substrate. The vertical interlayer spacing of the CoO films, deduced from a kinematic analysis of LEED I(E) curves, is a {sub perpendicular} {sub to} /2=2.17 Aa, slightly expanded along the film normal. Scanning Tunneling Microscopy (STM) show a big improvement in the surface roughness after annealing the CoO films at 750 K in oxygen atmosphere. Magnetic measurements using the magneto-optical Kerr effect (MOKE) show a characteristic increase of the coercive field when the Fe/CoO bilayer system is cooled down from room temperature to 150 K. The ordering temperature for the antiferromagnetic layer is in the same range as the Neel temperature for bulk CoO (T{sub N}=290 K). X-ray absorption spectroscopy was employed to probe magnetic and electronic properties with elemental selectivity. Absorption spectra taken from bilayers with different amounts of deposited Fe show only a weak indication for the formation of Fe oxide at the Fe/CoO interface (0.3 ML Fe). From the spectral shape it is concluded that an FeO type of oxide is formed. X-ray Magnetic Circular Dichroism (XMCD) measurements exhibit a sizeable induced ferromagnetic signal at the Co L{sub 2,3} absorption edge, corresponding to an interface layer of 1.1 ML in which the magnetic spins couple with the Fe layer. The angular dependence of the X-ray Magnetic Linear Dichroism (XMLD) and X-ray Magnetic Circular Dichroism XMCD at both the Co and Fe L{sub 2,3} edges shows the orientation of the Co and Fe moments in the bilayers with respect to the crystallographic direction. PhotoElectron Emission Microscope (PEEM) is used to image each ferromagnetic and antiferromagnetic layer separately. Magnetic contrast due to the induced magnetic spins at the interface is also

  11. Influence of ITO-Silver Wire Electrode Structure on the Performance of Single-Crystal Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Wern-Dare Jheng

    2012-01-01

    Full Text Available This study aimed to explore the effect of various electrode forms on single-crystal silicon solar cells by changing their front and back electrode structures. The high light penetration depth of the Indium Tin Oxide (ITO and the high conductivity of the silver wire that were coated on the single crystal silicon solar cells increased photoelectron export, thus increasing the efficiency of the solar cell. The experiment utilized a sol-gel solution containing phosphorus that was spin coated on single-crystal silicon wafers; this phosphorus also served as a phosphorus diffusion source. A p-n junction was formed after annealing at high temperature, and the substrate was coated with silver wires and ITO films of various structures to produce the electrodes. This study proposed that applying a heat treatment to the aluminum of back electrodes would result in a higher efficiency for single-crystal silicon solar cells, whereas single-crystal silicon solar cells containing front electrodes with ITO film coated with silver wires would result in efficiencies that are higher than those achieved using pure ITO thin-film electrodes.

  12. Structure and Growth Control of Organic–Inorganic Halide Perovskites for Optoelectronics: From Polycrystalline Films to Single Crystals

    Science.gov (United States)

    Chen, Yani; He, Minhong; Peng, Jiajun; Sun, Yong

    2016-01-01

    Recently, organic–inorganic halide perovskites have sparked tremendous research interest because of their ground‐breaking photovoltaic performance. The crystallization process and crystal shape of perovskites have striking impacts on their optoelectronic properties. Polycrystalline films and single crystals are two main forms of perovskites. Currently, perovskite thin films have been under intensive investigation while studies of perovskite single crystals are just in their infancy. This review article is concentrated upon the control of perovskite structures and growth, which are intimately correlated for improvements of not only solar cells but also light‐emitting diodes, lasers, and photodetectors. We begin with the survey of the film formation process of perovskites including deposition methods and morphological optimization avenues. Strategies such as the use of additives, thermal annealing, solvent annealing, atmospheric control, and solvent engineering have been successfully employed to yield high‐quality perovskite films. Next, we turn to summarize the shape evolution of perovskites single crystals from three‐dimensional large sized single crystals, two‐dimensional nanoplates, one‐dimensional nanowires, to zero‐dimensional quantum dots. Siginificant functions of perovskites single crystals are highlighted, which benefit fundamental studies of intrinsic photophysics. Then, the growth mechanisms of the previously mentioned perovskite crystals are unveiled. Lastly, perspectives for structure and growth control of perovskites are outlined towards high‐performance (opto)electronic devices. PMID:27812463

  13. Structure and Growth Control of Organic-Inorganic Halide Perovskites for Optoelectronics: From Polycrystalline Films to Single Crystals.

    Science.gov (United States)

    Chen, Yani; He, Minhong; Peng, Jiajun; Sun, Yong; Liang, Ziqi

    2016-04-01

    Recently, organic-inorganic halide perovskites have sparked tremendous research interest because of their ground-breaking photovoltaic performance. The crystallization process and crystal shape of perovskites have striking impacts on their optoelectronic properties. Polycrystalline films and single crystals are two main forms of perovskites. Currently, perovskite thin films have been under intensive investigation while studies of perovskite single crystals are just in their infancy. This review article is concentrated upon the control of perovskite structures and growth, which are intimately correlated for improvements of not only solar cells but also light-emitting diodes, lasers, and photodetectors. We begin with the survey of the film formation process of perovskites including deposition methods and morphological optimization avenues. Strategies such as the use of additives, thermal annealing, solvent annealing, atmospheric control, and solvent engineering have been successfully employed to yield high-quality perovskite films. Next, we turn to summarize the shape evolution of perovskites single crystals from three-dimensional large sized single crystals, two-dimensional nanoplates, one-dimensional nanowires, to zero-dimensional quantum dots. Siginificant functions of perovskites single crystals are highlighted, which benefit fundamental studies of intrinsic photophysics. Then, the growth mechanisms of the previously mentioned perovskite crystals are unveiled. Lastly, perspectives for structure and growth control of perovskites are outlined towards high-performance (opto)electronic devices.

  14. Structural and optical properties of Cd2+ ion on the growth of sulphamic acid single crystals

    Science.gov (United States)

    Rajyalakshmi, S.; Rao, Valluru Srinivasa; Reddy, P. V. S. S. S. N.; Krishna, V. Y. Rama; Samatha, K.; Rao, K. Ramachandra

    2016-05-01

    Transparent single crystals of Cadmium doped Sulphamic acid (SA) was grown by Conventional slow evaporation solution technique (SEST) which had the size of 13 × 8 × 7 mm3. The grown single crystals have been characterized using single crystal X-ray diffraction UV-visible Spectral studies and Second harmonic generation (SHG) efficiency and the results were discussed. The lattice parameters of the grown Cd2+ ion doped SA crystal are confirmed by single crystal X-ray diffraction and belong to orthorhombic system. Optical transmittance of the crystal was recorded using UV-vis NIR spectrophotometer with its lower cut off wavelength around 259nm. SHG measurements indicate that the SHG efficiency of the grown Cd2+ ion doped SA crystal at a fundamental wavelength of 1064 nm is approximately equal to KDP.

  15. Polycrystal deformation and single crystal deformation: Dislocation structure and flow stress in copper

    DEFF Research Database (Denmark)

    Huang, X.; Borrego, A.; Pantleon, W.

    2001-01-01

    The relation between the polycrystal deformation and single crystal deformation has been studied for pure polycrystalline copper deformed in tension. The dislocation microstructure has been analyzed for grains of different orientation by transmission electron microscopy (TEM) and three types...

  16. A critical analysis of national policies, systems, and structures of patient empowerment in England and Greece.

    Science.gov (United States)

    Boudioni, Markella; McLaren, Susan; Lister, Graham

    2017-01-01

    Comparison of patient empowerment (PE) policies in European countries can provide evidence for improvement and reform across different health systems. It may also influence patient and public involvement, patient experience, preference, and adherence. The objective of this study was to compare PE within national policies, systems, and structures in England and Greece for achieving integrated people-centered health services. We performed a critical search and review of policy and legislation papers in English and Greek languages. This included 1) general health policy and systems papers, 2) PE, patient and/or public involvement or patients' rights policy and legislation (1990-2015), and 3) comparative or discussion papers for England and/or Greece. A total of 102 papers on PE policies, systems, and structures were identified initially; 80 papers were included, in which 46 were policy, legislative, and discussion papers about England, 21 were policy, legislation, and discussion papers about Greece, and 13 were comparative or discussion papers including both the countries. In England, National Health Service policies emphasized patient-centered services, involvement, and empowerment, with recent focus on patients' rights; while in Greece, they emphasized patients' rights and quality of services, with recent mentions on empowerment. The health ombudsman is a very important organization across countries; however, it may be more powerful in Greece, because of the nonexistence of local mediating bodies. Micro-structures at trusts/hospitals are comparable, but legislation gives more power to the local structures in Greece. PE policies and systems have been developed and expressed differently in these countries. However, PE similarities, comparable dimensions and mechanisms, were identified. For both the countries, comparative research and these findings could be beneficial in building connections and relationships, contributing to wider European and international

  17. Ferroelectric InMnO{sub 3}: Growth of single crystals, structure and high-temperature phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Bekheet, Maged F., E-mail: maged.bekheet@ceramics.tu-berlin.de [Fachbereich Material‐ und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institut für Werkstoffwissenschaften und -technologien, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin (Germany); Svoboda, Ingrid; Liu, Na [Fachbereich Material‐ und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Bayarjargal, Lkhamsuren [Institut für Geowissenschaften, Goethe-Universität, Altenhöferallee 1, d-60438 Frankfurt a.M. (Germany); Irran, Elisabeth [Institut für Chemie, Technische Universität Berlin, Straße des 17, Juni 135, 10623 Berlin (Germany); Dietz, Christian; Stark, Robert W.; Riedel, Ralf [Fachbereich Material‐ und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Gurlo, Aleksander [Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institut für Werkstoffwissenschaften und -technologien, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin (Germany)

    2016-09-15

    To understand the origin of the ferroelectricity in InMnO{sub 3}, single crystals with average size of 1 mm were grown in PbF{sub 2} flux at 950 °C. The results of single crystal X-ray diffraction, second harmonic generation and piezoresponse force microscopy studies of high-quality InMnO{sub 3} single crystals reveal that the room-temperature state in this material is ferroelectric with P6{sub 3}cm symmetry. The polar InMnO{sub 3} specimen undergoes a reversible phase transition from non-centrosymmetric P6{sub 3}cm structure to a centrosymmetric P6{sub 3}/mmc structure at 700 °C as confirmed by the in situ high-temperature Raman spectroscopic and synchrotron X-ray diffraction experiments. - Graphical abstract: Piezoresponse fore microscopy (PFM) studies of high quality InMnO{sub 3} single crystal revealed that the room-temperature state of this material is ferroelectric with a clear cloverleaf pattern corresponding to six antiphase ferroelectric domains with alternating polarization ±P{sub z}. Display Omitted - Highlights: • InMnO{sub 3} single crystals with average size of 1 mm were grown in PbF{sub 2} flux at 950 °C. • The room-temperature state of InMnO{sub 3} is ferroelectric with polar P6{sub 3}cm structure. • PolarInMnO{sub 3} reversibly transforms to a centrosymmetric P6{sub 3}/mmc structure above 700 °C.

  18. Clonal diversity and population genetic structure of arbuscular mycorrhizal fungi (Glomus spp.) studied by multilocus genotyping of single spores

    DEFF Research Database (Denmark)

    Holtgrewe-Stukenbrock, Eva; Rosendahl, Søren

    2005-01-01

    A nested multiplex PCR (polymerase chain reaction) approach was used for multilocus genotyping of arbuscular mycorrhizal fungal populations. This method allowed us to amplify multiple loci from Glomus single spores in a single PCR amplification. Variable introns in the two protein coding genes Gm......FOX2 and GmTOR2 were applied as codominant genetic markers together with the LSU rDNA.   Genetic structure of Glomus spp. populations from an organically and a conventionally cultured field were compared by hierarchical sampling of spores from four plots in each field. Multilocus genotypes were...

  19. Crystal Structure and Physical Properties of U3T3Sn4 (T = Ni, Cu) Single-Crystals

    OpenAIRE

    Shlyk, L.; Estrela, P.; Waerenborgh, J. C.; De Long, L. E.; de Visser, A.; Rojas, D. P.; Gandra, F.; Almeida, M.

    2000-01-01

    Heat capacity experiments, crystal structure determination and transmission electron microscopy have been carried out on U3Cu3Sn4 single-crystals. U3Cu3Sn4 was confirmed to be a heavy-fermion antiferromagnet (TN=13(1) K) with a low temperature electronic heat capacity coefficient gamma=390 mJ/molUK2. Low temperature heat capacity experiments on a U3Ni3Sn4 single-crystal indicate that below 0.4 K there is a crossover between the previously observed non-Fermi liquid behavior and a Fermi liquid ...

  20. Conversion of broadband IR radiation and structural disorder in lithium niobate single crystals with low photorefractive effect

    Science.gov (United States)

    Litvinova, Man Nen; Syuy, Alexander V.; Krishtop, Victor V.; Pogodina, Veronika A.; Ponomarchuk, Yulia V.; Sidorov, Nikolay V.; Gabain, Aleksei A.; Palatnikov, Mikhail N.; Litvinov, Vladimir A.

    2016-11-01

    The conversion of broadband IR radiation when the noncritical phase matching condition is fulfilled in lithium niobate (LiNbO3) single crystals with stoichiometric (R = Li/Nb = 1) and congruent (R = 0.946) compositions, as well as in congruent single crystals doped with zinc has been investigated. It is shown that the spectrum parameters of converted radiation, such as the conversion efficiency, spectral width and position of maximum, depend on the ordering degree of structural units of the cation sublattice along the polar axis of crystal.

  1. Crystal growth, structure analysis and characterisation of 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Sankari, R. Siva, E-mail: sivasankari.sh@act.edu.in [Department of Physics, Agni College of Technology, Thalambur, Chennai-603103 (India); Perumal, Rajesh Narayana [Department of Physics, SSN College of Engineering, Kalavakkam, Chennai-603110 (India)

    2014-04-24

    Single crystal of dielectric material 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid has been grown by slow evaporation solution growth method. The grown crystal was harvested in 25 days. The crystal structure was analyzed by Single crystal X - ray diffraction. UV-vis-NIR analysis was performed to examine the optical property of the grown crystal. The thermal property of the grown crystal was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The dielectric measurements were carried out and the dielectric constant was calculated and plotted at all frequencies.

  2. Optimized design and structural mechanics of a single-piece composite helicopter driveshaft

    Science.gov (United States)

    Henry, Todd C.

    In rotorcraft driveline design, single-piece composite driveshafts have much potential for reducing driveline mass and complexity over multi-segmented metallic driveshafts. The singlepiece shaft concept is enabled by the relatively high fatigue strain capacity of fiber reinforced polymer composites over metals. Challenges for single-piece driveshaft design lie in addressing the self-heating behavior of the composite due to the material damping, as well as, whirling stability, torsional buckling stability, and composite strength. Increased composite temperature due to self-heating reduces the composite strength and is accounted for in this research. The laminate longitudinal stiffness ( Ex) and strength (Fx) are known to be heavily degraded by fiber undulation, however, both are not well understood in compression. The whirling stability (a function of longitudinal stiffness) and the composite strength are strongly influential in driveshaft optimization, and thus are investigated further through the testing of flat and filament wound composite specimens. The design of single-piece composite driveshafts, however, needs to consider many failure criteria, including hysteresis-induced overheating, whirl stability, torsional buckling stability, and material failure by overstress. The present investigation uses multi-objective optimization to investigate the design space which visually highlights design trades. Design variables included stacking sequence, number of laminas, and number of hanger bearings. The design goals were to minimize weight and maximize the lowest factor of safety by adaptively generating solutions to the multi-objective problem. Several design spaces were investigated by examining the effect of misalignment, ambient temperature, and constant power transmission on the optimized solution. Several materials of interest were modeled using experimentally determined elastic properties and novel temperature-dependent composite strength. Compared to the

  3. The silver fir in the Val Grande National Park: distribution, structures and dynamics

    Directory of Open Access Journals (Sweden)

    2004-01-01

    Full Text Available The Val Grande National Park, designated in 1992, is considered to be the largest wilderness area in the European Alps. The aim of the present study was to determine the distribution of silver fir (Abies alba Mill. within the Val Grande National Park and to analyse structure, natural and human disturbances and dynamics in an intensive monitoring plot located on Monte Mottac. Results showed that silver fir distribution in the stand is discontinuous and limited to the northern sector. Most silver fir grows in mixed populations with beech (Fagus sylvatica L. and, to a lesser extent, with Norway spruce (Picea Abies (L. Karts. and other broadleaves. The stand studied was found to be uneven-aged with some individuals older than 150 years and many below 60 years. Analysis of abrupt growth releases allowed the detection of two cuts that took place in the 20th century, the latter of which was conducted at the beginning of the 50s. The results show that although human influence is still evident, in the last decades natural dynamics have become the predominant influence in the forest's structures and processes.

  4. DSSTOX NATIONAL TOXICOLOGY PROGRAM BIOASSAY ON-LINE DATABASE STRUCTURE-INDEX LOCATOR FILE: SDF FILE AND DOCUMENTATION

    Science.gov (United States)

    NTPBSI: National Toxicology Program Bioassay On-line Database Structure-Index Locator File. Database contains the results collected on approxiately 300 toxicity studies from shorter duration test and from genetic toxicity studies, both in vitro and in vivo tests.

  5. Technological and operational structure of the National Automatic Network for Environmental Radiological Monitoring (RENAMORA)

    International Nuclear Information System (INIS)

    Martinez G, E.; Lopez G, M.; Aguirre G, J.; Fabian O, R.; Hernandez A, Y.

    2015-09-01

    The Comision Nacional de Seguridad Nuclear y Salvaguardias (CNSNS) in Mexico is a decentralized body, under the Secretaria de Energia whose main mission is to ensure that activities involving nuclear and radioactive materials as well as ionizing radiation sources are carried out with maximum security, considering the current technological developments. In order to monitor the levels of environmental radiation to which the population is exposed, the CNSNS has established a series of radiological monitoring programs that allow characterize the environmental radiation levels in each zone or region in the country; to identify the occurrence of natural or artificial radiological events, such as nuclear tests and accidents in radioactive or nuclear facilities. The National Automatic Network for Environmental Radiological Monitoring (RENAMORA) project was initiated with the support of the IAEA through MEX9/049 project and its purpose is to have a network of instruments that automatically and in real time, transmit information of the gamma radiological environmental status of the national territory and changes occurring in it. This network provides data such as the speed of ambient dose equivalent, temperature and humidity in different regions of the country. The network is composed of 92 stations that are distributed throughout the national territory. The structure of the stations has evolved since its inception, now allowing detection tasks, data transmission and managing them remotely from the main server, which is located in the CNSNS, which is performed a statistical dose for each monitoring station. Each monitoring station is formed in its current structure by a probe detection of gamma radiation, a communication module and associated electronics, a mini Web server DataGATE, a cellular modem and an interface converter. (Author)

  6. The relationship between elastic constants and structure of shock waves in a zinc single crystal

    Science.gov (United States)

    Krivosheina, M. N.; Kobenko, S. V.; Tuch, E. V.

    2017-12-01

    The paper provides a 3D finite element simulation of shock-loaded anisotropic single crystals on the example of a Zn plate under impact using a mathematical model, which allows for anisotropy in hydrostatic stress and wave velocities in elastic and plastic ranges. The simulation results agree with experimental data, showing the absence of shock wave splitting into an elastic precursor and a plastic wave in Zn single crystals impacted in the [0001] direction. It is assumed that the absence of an elastic precursor under impact loading of a zinc single crystal along the [0001] direction is determined by the anomalously large ratio of the c/a-axes and close values of the propagation velocities of longitudinal and bulk elastic waves. It is shown that an increase in only one elastic constant along the [0001] direction results in shock wave splitting into an elastic precursor and a shock wave of "plastic" compression.

  7. Book of abstracts of 13. national conference on nuclear structure and 9. symposium on 'nuclear structure and quantum mechanics'

    International Nuclear Information System (INIS)

    2010-07-01

    13. national conference on nuclear structure and 9. symposium on 'nuclear structure and quantum mechanics' was held by China Nuclear Physics Society in Chifeng, 25 to 30 July, 2010. The proceedings collects the abstracts of 102 articles

  8. IPET and FETR: experimental approach for studying molecular structure dynamics by cryo-electron tomography of a single-molecule structure.

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    Full Text Available The dynamic personalities and structural heterogeneity of proteins are essential for proper functioning. Structural determination of dynamic/heterogeneous proteins is limited by conventional approaches of X-ray and electron microscopy (EM of single-particle reconstruction that require an average from thousands to millions different molecules. Cryo-electron tomography (cryoET is an approach to determine three-dimensional (3D reconstruction of a single and unique biological object such as bacteria and cells, by imaging the object from a series of tilting angles. However, cconventional reconstruction methods use large-size whole-micrographs that are limited by reconstruction resolution (lower than 20 Å, especially for small and low-symmetric molecule (<400 kDa. In this study, we demonstrated the adverse effects from image distortion and the measuring tilt-errors (including tilt-axis and tilt-angle errors both play a major role in limiting the reconstruction resolution. Therefore, we developed a "focused electron tomography reconstruction" (FETR algorithm to improve the resolution by decreasing the reconstructing image size so that it contains only a single-instance protein. FETR can tolerate certain levels of image-distortion and measuring tilt-errors, and can also precisely determine the translational parameters via an iterative refinement process that contains a series of automatically generated dynamic filters and masks. To describe this method, a set of simulated cryoET images was employed; to validate this approach, the real experimental images from negative-staining and cryoET were used. Since this approach can obtain the structure of a single-instance molecule/particle, we named it individual-particle electron tomography (IPET as a new robust strategy/approach that does not require a pre-given initial model, class averaging of multiple molecules or an extended ordered lattice, but can tolerate small tilt-errors for high-resolution single

  9. Fluctuation in Interface and Electronic Structure of Single-Molecule Junctions Investigated by Current versus Bias Voltage Characteristics.

    Science.gov (United States)

    Isshiki, Yuji; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

    2018-03-14

    Structural and electronic detail at the metal-molecule interface has a significant impact on the charge transport across the molecular junctions, but its precise understanding and control still remain elusive. On the single-molecule scale, the metal-molecule interface structures and relevant charge transport properties are subject to fluctuation, which contain the fundamental science of single-molecule transport and implication for manipulability of the transport properties in electronic devices. Here, we present a comprehensive approach to investigate the fluctuation in the metal-molecule interface in single-molecule junctions, based on current-voltage ( I- V) measurements in combination with first-principles simulation. Contrary to conventional molecular conductance studies, this I- V approach provides a correlated statistical description of both the degree of electronic coupling across the metal-molecule interface and the molecular orbital energy level. This statistical approach was employed to study fluctuation in single-molecule junctions of 1,4-butanediamine (DAB), pyrazine (PY), 4,4'-bipyridine (BPY), and fullerene (C 60 ). We demonstrate that molecular-dependent fluctuation of σ-, π-, and π-plane-type interfaces can be captured by analyzing the molecular orbital (MO) energy level under mechanical perturbation. While the MO level of DAB with the σ-type interface shows weak distance dependence and fluctuation, the MO level of PY, BPY, and C 60 features unique distance dependence and molecular-dependent fluctuation against the mechanical perturbation. The MO level of PY and BPY with the σ+π-type interface increases with the increase in the stretch distance. In contrast, the MO level of C 60 with the π-plane-type interface decreases with the increase in the stretching perturbation. This study provides an approach to resolve the structural and electronic fluctuation in the single-molecule junctions and insight into the molecular-dependent fluctuation in

  10. Advantages of using raw materials in low cost sustainable structural solutions for single-family buildings

    OpenAIRE

    Murta, A.; Teixeira, C.; Varum, H.; Bentes, I.; Pinto, J.

    2010-01-01

    In the last decades, the Portuguese housing building industry has been mainly fo-cused on the construction based on reinforced concrete framed structures and non-structural clay brick masonry for exterior and interior partition walls. Recently, this industry started to in-clude alternative structural materials, such as steel and timber. The earth based construction techniques and solutions still remains limited to individual cases, in which the owner and/or contractor have a particular concer...

  11. Shedding light on protein folding, structural and functional dynamics by single molecule studies

    DEFF Research Database (Denmark)

    Bavishi, Krutika; Hatzakis, Nikos

    2014-01-01

    The advent of advanced single molecule measurements unveiled a great wealth of dynamic information revolutionizing our understanding of protein dynamics and behavior in ways unattainable by conventional bulk assays. Equipped with the ability to record distribution of behaviors rather than the mean...... property of a population, single molecule measurements offer observation and quantification of the abundance, lifetime and function of multiple protein states. They also permit the direct observation of the transient and rarely populated intermediates in the energy landscape that are typically averaged out...

  12. Preparation and single molecule structure of electroactive polysilane end-grafted on a crystalline silicon surface

    Science.gov (United States)

    Furukawa, Kazuaki; Ebata, Keisuke

    2000-12-01

    Electrically active polysilanes of poly(methylphenylsilane) (PMPS) and poly[bis(p-n-butylphenyl)silane] (PBPS), which are, respectively, known as a good hole transporting material and a near-ultraviolet electroluminescent material, are end-grafted directly on a crystalline silicon surface. The single polysilane molecules are clearly distinguished one from the other on the surface by means of atomic force microscopy observations. End-grafted single molecules of PMPS are observed as dots while end-grafted PBPS appear as worms extending for more than 100 nm on the crystalline silicon surface.

  13. Single-fluorophore monitoring of DNA hybridization for investigating the effect of secondary structure on the nucleation step.

    Science.gov (United States)

    Jo, Joon-Jung; Kim, Min-Ji; Son, Jung-Tae; Kim, Jandi; Shin, Jong-Shik

    2009-07-17

    Nucleic acid hybridization is one of the essential biological processes involved in storage and transmission of genetic information. Here we quantitatively determined the effect of secondary structure on the hybridization activation energy using structurally defined oligonucleotides. It turned out that activation energy is linearly proportional to the length of a single-stranded region flanking a nucleation site, generating a 0.18 kcal/mol energy barrier per nucleotide. Based on this result, we propose that the presence of single-stranded segments available for non-productive base pairing with a nucleation counterpart extends the searching process for nucleation sites to find a perfect match. This result may provide insights into rational selection of a target mRNA site for siRNA and antisense gene silencing.

  14. Determination of the ribosome structure to a resolution of 2.5 Å by single-particle cryo-EM.

    Science.gov (United States)

    Liu, Zheng; Gutierrez-Vargas, Cristina; Wei, Jia; Grassucci, Robert A; Sun, Ming; Espina, Noel; Madison-Antenucci, Susan; Tong, Liang; Frank, Joachim

    2017-01-01

    With the advance of new instruments and algorithms, and the accumulation of experience over decades, single-particle cryo-EM has become a pivotal part of structural biology. Recently, we determined the structure of a eukaryotic ribosome at 2.5 Å for the large subunit. The ribosome was derived from Trypanosoma cruzi, the protozoan pathogen of Chagas disease. The high-resolution density map allowed us to discern a large number of unprecedented details including rRNA modifications, water molecules, and ions such as Mg 2+ and Zn 2+ . In this paper, we focus on the procedures for data collection, image processing, and modeling, with particular emphasis on factors that contributed to the attainment of high resolution. The methods described here are readily applicable to other macromolecules for high-resolution reconstruction by single-particle cryo-EM. © 2016 The Protein Society.

  15. Improving accuracy of overhanging structures for selective laser melting through reliability characterization of single track formation on thick powder beds

    DEFF Research Database (Denmark)

    Mohanty, Sankhya; Hattel, Jesper Henri

    2016-01-01

    Repeatability and reproducibility of parts produced by selective laser melting is a standing issue, and coupled with a lack of standardized quality control presents a major hindrance towards maturing of selective laser melting as an industrial scale process. Consequently, numerical process...... modelling has been adopted towards improving the predictability of the outputs from the selective laser melting process. Establishing the reliability of the process, however, is still a challenge, especially in components having overhanging structures.In this paper, a systematic approach towards...... establishing reliability of overhanging structure production by selective laser melting has been adopted. A calibrated, fast, multiscale thermal model is used to simulate the single track formation on a thick powder bed. Single tracks are manufactured on a thick powder bed using same processing parameters...

  16. Interaction of hnRNP A1 with telomere DNA G-quadruplex structures studied at the single molecule level

    DEFF Research Database (Denmark)

    Krüger, Asger Christian; Raarup, Merete Krog; Nielsen, Morten Muhlig

    2010-01-01

    G-rich telomeric DNA sequences can form G-quadruplex structures. The heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and a shortened derivative (UP1) are active in telomere length regulation, and it has been reported that UP1 can unwind G-quadruplex structures. Here, we investigate...... the interaction of hnRNP A1 with G-quadruplex DNA structures containing the human telomere repeat (TTAGGG) by gel retardation assays, ensemble fluorescence energy transfer (FRET) spectroscopy, and single molecule FRET microscopy. Our biochemical experiments show that hnRNP A1 binds well to the G...... to the previously reported crystal structures of UP1-telomere DNA complexes where the DNA oligo within the protein-DNA complex is in a fully open conformation....

  17. Controlling Structural Characteristics of Single-Walled Carbon Nanotubes (SWNT) by Tailoring Catalyst Composition and Synthesis Conditions

    International Nuclear Information System (INIS)

    Resasco, Daniel E.

    2010-01-01

    This report shows the extensive research on the mechanism responsible for the formation of single walled carbon nanotubes in order to get control over their structural parameters (diameter and chirality). Catalyst formulations, pre-treatment conditions, and reaction conditions are described in detail as well as mechanisms to produce nanotubes structures of specific arrays (vertical forest, nanotube pillars). Applications of SWNT in different fields are also described in this report. In relation to this project five students have graduated (3 PhD and 2 MS) and 35 papers have been published.

  18. Investigation of the single Particle Structure of the neutron-rich Sodium Isotopes $^{27-31}\\!$Na

    CERN Multimedia

    2002-01-01

    We propose to study the single particle structure of the neutron-rich isotopes $^{27-31}\\!$Na. These isotopes will be investigated via neutron pickup reactions in inverse kinematics on a deuterium and a beryllium target. Scattered beam particles and transfer products are detected in a position sensitive detector located around 0$^\\circ$. De-excitation $\\gamma$-rays emitted after an excited state has been populated will be registered by the MINIBALL Germanium array. The results will shed new light on the structure of the neutron-rich sodium isotopes and especially on the region of strong deformation around the N=20 nucleus $^{31}\\!$Na.

  19. Structural characterization of metastable hcp-Ni thin films epitaxially grown on Au(100) single-crystal underlayers

    International Nuclear Information System (INIS)

    Ohtake, Mitsuru; Tanaka, Takahiro; Futamoto, Masaaki; Kirino, Fumiyoshi

    2010-01-01

    Ni(1120) epitaxial thin films with hcp structure were prepared on Au(100) single-crystal underlayers at 100 deg. C by ultra high vacuum molecular beam epitaxy. The detailed film structure is studied by in situ reflection high energy electron diffraction, x-ray diffraction, and transmission electron microscopy. The hcp-Ni film consists of two types of variants whose c-axes are rotated around the film normal by 90 deg. each other. An atomically sharp boundary is recognized between the film and the underlayer, where misfit dislocations are introduced. Presence of such dislocations seems to relieve the strain caused by the lattice mismatch between the film and the underlayer.

  20. Synchrotron Topographic and Diffractometer Studies of Buried Layered Structures Obtained by Implantation with Swift Heavy Ions in Silicon Single Crystals

    International Nuclear Information System (INIS)

    Wierzchowski, W.; Wieteska, K.; Zymierska, D.; Graeff, W.; Czosnyka, T.; Choinski, J.

    2006-01-01

    A distribution of crystallographic defects and deformation in silicon crystals subjected to deep implantation (20-50 μm) with ions of the energy of a few MeV/amu is studied. Three different buried layered structures (single layer, binary buried structure and triple buried structure) were obtained by implantation of silicon single crystals with 184 MeV argon ions, 29.7 MeV boron ions, and 140 MeV argon ions, each implantation at a fluency of 1x10 14 ions cm -2 . The implanted samples were examined by means of white beam X-ray section and projection topography, monochromatic beam topography and by recording local rocking curves with the beam restricted to 50 x 50 μm 2 . The experiment pointed to a very low level of implantation-induced strain (below 10 -5 ). The white beam Bragg case section experiment revealed a layer producing district black contrast located at a depth of the expected mean ion range. The presence of these buried layered structures in studied silicon crystals strongly affected the fringe pattern caused by curvature of the samples. In case of white beam projection and monochromatic beam topographs the implanted areas were revealed as darker regions with a very tiny grain like structure. One may interpret these results as the effect of considerable heating causing annihilation of point defects and formation of dislocation loops connected with point defect clusters. (author)

  1. Adenovirus DNA replication in vitro: Duplication of single-stranded DNA containing a panhandle structure

    NARCIS (Netherlands)

    Leegwater, P.A.J.; Rombouts, R.F.A.; Vliet, P.C. van der

    1988-01-01

    Adenovirus DNA replicates by displacement of one of the parental strands followed by duplication of the displaced parental single strand (complementary strand synthesis). Displacement synthesis has been performed in a reconstituted system composed of viral and cellular proteins, employing either the

  2. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Mottaghitalab, Fatemeh [Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Farokhi, Mehdi [National cell bank of Iran, Pasteur Institute, Tehran (Iran, Islamic Republic of); Atyabi, Fatemeh [Department of Pharmaceutical Nanoechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Omidvar, Ramin [Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National cell bank of Iran, Pasteur Institute, Tehran (Iran, Islamic Republic of); Sadeghizadeh, Majid, E-mail: sadeghma@modares.ac.ir [Department Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2015-06-01

    Highlights: • Increasing the cytocompatibility of single walled carbon nanotube by loading fibronectin. • Enhancing the hydrophilicity and nanosurface roughness of single walled carbon nanotube after loading fibronectin. • Fibronectin makes the surface properties of single walled carbon nanotube more suitable for cell proliferation and growth. - Abstract: Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT.

  3. Fully Streched Single DNA Molecules in a Nanofluidic Chip Show Large-Scale Structural Variation

    DEFF Research Database (Denmark)

    Pedersen, Jonas Nyvold; Marie, Rodolphe; Bauer, D. L.

    2013-01-01

    When stretching and imaging DNA molecules in nanofluidic devices, it is important to know the relation between the physical length as measured in the lab and the distance along the contour of the DNA. Here a single DNA molecule longer than 1 Mbp is loaded into a nanofluidic device consisting of two...

  4. The Relation between Structure and Quantum Interference in Single Molecule Junctions

    DEFF Research Database (Denmark)

    Markussen, Troels; Stadler, Robert; Thygesen, Kristian Sommer

    2010-01-01

    Quantum interference (QI) of electron pathways has recently attracted increased interest as an enabling tool for single-molecule electronic devices. Although various molecular systems have been shown to exhibit QI effects and a number of methods have been proposed for its analysis, simple...

  5. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    International Nuclear Information System (INIS)

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Atyabi, Fatemeh; Omidvar, Ramin; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2015-01-01

    Highlights: • Increasing the cytocompatibility of single walled carbon nanotube by loading fibronectin. • Enhancing the hydrophilicity and nanosurface roughness of single walled carbon nanotube after loading fibronectin. • Fibronectin makes the surface properties of single walled carbon nanotube more suitable for cell proliferation and growth. - Abstract: Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT

  6. Holography and coherent diffraction with low-energy electrons: A route towards structural biology at the single molecule level

    Energy Technology Data Exchange (ETDEWEB)

    Latychevskaia, Tatiana; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner, E-mail: hwfink@physik.uzh.ch

    2015-12-15

    The current state of the art in structural biology is led by NMR, X-ray crystallography and TEM investigations. These powerful tools however all rely on averaging over a large ensemble of molecules. Here, we present an alternative concept aiming at structural analysis at the single molecule level. We show that by combining electron holography and coherent diffraction imaging estimations concerning the phase of the scattered wave become needless as the phase information is extracted from the data directly and unambiguously. Performed with low-energy electrons the resolution of this lens-less microscope is just limited by the De Broglie wavelength of the electron wave and the numerical aperture, given by detector geometry. In imaging freestanding graphene, a resolution of 2 Å has been achieved revealing the 660.000 unit cells of the graphene sheet from a single data set. Once applied to individual biomolecules the method shall ultimately allow for non-destructive imaging and imports the potential to distinguish between different conformations of proteins with atomic resolution. - Highlights: • Structural biology of single proteins. • Radiation damage-free imaging of individual biomolecules. • Holography. • Low-energy electrons. • Coherent diffraction and phase retrieval.

  7. Synthesis, growth, structure, mechanical and optical properties of a new semi-organic 2-methyl imidazolium dihydrogen phosphate single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nagapandiselvi, P., E-mail: nagapandiselvip@ssn.edu.in [Department of Physics, SSN College of Engineering, Kalavakkam (India); Baby, C. [Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai (India); Gopalakrishnan, R. [Crystal Research Lab, Department of Physics, Anna University, Chennai (India)

    2016-09-15

    Highlights: • 2MIDP crystals were grown by slow evaporation solution growth technique. • Single crystal XRD revealed self-assembled supramolecular framework. • Z scan technique is employed for third order nonlinear optical susceptibility. • Structure-property correlation is established. - Abstract: A new semi-organic compound, 2-methyl imidazolium dihydrogen phosphate (2MIDP), was prepared and good quality single crystals of 2MIDP were grown by slow evaporation solution growth technique. Crystal structure elucidated using Single crystal XRD showed that 2MIDP crystallizes in monoclinic system with P2{sub 1}/c space group. FT-IR, UV-Vis-NIR, Fluorescence and FT-NMR spectra confirm the molecular structure of 2MIDP. The UV-Vis-NIR spectra established the suitability of the compound for NLO applications. TG-DSC showed that 2MIDP is thermally stable up to 200 °C. Mechanical characteristics like hardness number (H{sub v}), stiffness constant (C{sub 11}), yield strength (σ{sub v}), fracture toughness (K{sub c}) and brittleness index (B{sub i}) were assessed using Vicker’s microhardness tester. Third order nonlinear optical properties determined from Z-scan measurement using femto and picosecond lasers showed two photon reverse saturable absorption. The enhancement of nonlinear optical properties in femto second laser, revealed the suitability of 2MIDP for optical limiting applications.

  8. Using a single structure for three sensor operations and two actuator operations

    NARCIS (Netherlands)

    Langereis, G.R.; Olthuis, Wouter; Bergveld, Piet

    1998-01-01

    In many process control applications, a set of separate existing sensor structures is placed in the environment of interest and not much attention is being paid to the integration of these structures and even less to the possibility of combining the measurement results obtained from these sensor

  9. Structural changes in single chromatin fibers induced by tension and torsion

    NARCIS (Netherlands)

    Meng, He

    2014-01-01

    Since the discovery of the right-handed helical structure of DNA, 61 years have passed. The DNA molecule, which encodes genetic information, is also found twisted into coils. This extra twist of the helical structure, called supercoiling, plays important roles in both DNA compaction and gene

  10. Modulated antiferromagnetic structure of Nd1-xPrx single crystals

    DEFF Research Database (Denmark)

    McEwen, K. A.; Lebech, Bente; Fort, D.

    1986-01-01

    Neutron diffraction studies of Nd0.75Pr0.25 and Nd0.65Pr0.35 are reported for T≥3K. The magnetic structure of these DHCP alloys is simpler than that of pure Nd: only satellites with qh≈0.13 τ100 were found. The structure has moments on both the hexagonal and cubic sites...

  11. Structure, function, and self-assembly of single network gyroid (I4132) photonic crystals in butterfly wing scales

    Science.gov (United States)

    Saranathan, Vinodkumar; Osuji, Chinedum O.; Mochrie, Simon G. J.; Noh, Heeso; Narayanan, Suresh; Sandy, Alec; Dufresne, Eric R.; Prum, Richard O.

    2010-01-01

    Complex three-dimensional biophotonic nanostructures produce the vivid structural colors of many butterfly wing scales, but their exact nanoscale organization is uncertain. We used small angle X-ray scattering (SAXS) on single scales to characterize the 3D photonic nanostructures of five butterfly species from two families (Papilionidae, Lycaenidae). We identify these chitin and air nanostructures as single network gyroid (I4132) photonic crystals. We describe their optical function from SAXS data and photonic band-gap modeling. Butterflies apparently grow these gyroid nanostructures by exploiting the self-organizing physical dynamics of biological lipid-bilayer membranes. These butterfly photonic nanostructures initially develop within scale cells as a core-shell double gyroid (Ia3d), as seen in block-copolymer systems, with a pentacontinuous volume comprised of extracellular space, cell plasma membrane, cellular cytoplasm, smooth endoplasmic reticulum (SER) membrane, and intra-SER lumen. This double gyroid nanostructure is subsequently transformed into a single gyroid network through the deposition of chitin in the extracellular space and the degeneration of the rest of the cell. The butterflies develop the thermodynamically favored double gyroid precursors as a route to the optically more efficient single gyroid nanostructures. Current approaches to photonic crystal engineering also aim to produce single gyroid motifs. The biologically derived photonic nanostructures characterized here may offer a convenient template for producing optical devices based on biomimicry or direct dielectric infiltration. PMID:20547870

  12. Inferring biological structures from super-resolution single molecule images using generative models.

    Directory of Open Access Journals (Sweden)

    Suvrajit Maji

    Full Text Available Localization-based super resolution imaging is presently limited by sampling requirements for dynamic measurements of biological structures. Generating an image requires serial acquisition of individual molecular positions at sufficient density to define a biological structure, increasing the acquisition time. Efficient analysis of biological structures from sparse localization data could substantially improve the dynamic imaging capabilities of these methods. Using a feature extraction technique called the Hough Transform simple biological structures are identified from both simulated and real localization data. We demonstrate that these generative models can efficiently infer biological structures in the data from far fewer localizations than are required for complete spatial sampling. Analysis at partial data densities revealed efficient recovery of clathrin vesicle size distributions and microtubule orientation angles with as little as 10% of the localization data. This approach significantly increases the temporal resolution for dynamic imaging and provides quantitatively useful biological information.

  13. Status of High Power Tests of Normal Conducting Single-Cell Standing Wave Structures

    Energy Technology Data Exchange (ETDEWEB)

    Dolgashev, Valery; /SLAC; Tantawi, Sami; /SLAC; Yeremian, Anahid; /SLAC; Higashi, Yasuo; /KEK, Tsukuba; Spataro, Bruno; /INFN, Rome

    2012-06-25

    Our experiments are directed toward the understanding of the physics of rf breakdown in systems that can be used to accelerate electron beams at {approx}11.4 GHz. The structure geometries have apertures, stored energy per cell, and rf pulse duration close to that of the NLC or CLIC. The breakdown rate is the main parameter that we use to compare rf breakdown behavior for different structures at a given set of rf pulse parameters (pulse shape and peak power) at 60 Hz repetition rate. In our experiments, the typical range of the breakdown rate is from one per few hours to {approx}100 per hour. To date we have tested 29 structures. We consistently found that after the initial conditioning, the behavior of the breakdown rate is reproducible for structures of the same geometry and material, and the breakdown rate dependence on peak magnetic fields is stronger than on peak surface electric fields for structures of different geometries. Below we report the main results from tests of seven structures made from hard copper, soft copper alloys and hard-copper alloys. Additional details on these and other structures will be discussed in future publications.

  14. Crystal structure analysis, overexpression and refolding behaviour of a DING protein with single mutation

    International Nuclear Information System (INIS)

    Gai, Zuoqi; Nakamura, Akiyoshi; Tanaka, Yoshikazu; Hirano, Nagisa; Tanaka, Isao; Yao, Min

    2013-01-01

    Crystals of a member of the DING protein family (HPBP) were obtained accidentally, and the structure was determined at 1.35 Å resolution. For further analysis, a system for preparation of HPBP was constructed and the structure of a prepared sample was confirmed by X-ray crystal structure analysis at 1.03 Å resolution. After crystallization of a certain protein–RNA complex, well diffracting crystals were obtained. However, the asymmetric unit of the crystal was too small to locate any components. Mass spectrometry and X-ray crystal structure analysis showed that it was a member of the DING protein family (HPBP). Surprisingly, the structure of HPBP reported previously was also determined accidentally as a contaminant, suggesting that HPBP has a strong tendency to crystallize. Furthermore, DING proteins were reported to relate in disease. These observations suggest that DING has potential for application in a wide range of research fields. To enable further analyses, a system for preparation of HPBP was constructed. As HPBP was expressed in insoluble form in Escherichia coli, it was unfolded chemically and refolded. Finally, a very high yield preparation method was constructed, in which 43 mg of HPBP was obtained from 1 L of culture. Furthermore, to evaluate the validity of refolding, its crystal structure was determined at 1.03 Å resolution. The determined structure was identical to the native structure, in which two disulfide bonds were recovered correctly and a phosphate ion was captured. Based on these results, it was concluded that the refolded HPBP recovers its structure correctly

  15. Vegetation structure in the mountain forest in the Turquino National Park, province of Granma

    Directory of Open Access Journals (Sweden)

    José Luis Rodríguez Sosa

    2013-12-01

    Full Text Available The research was conducted in the Jeringa site of the Turquino National Park in order to characterize the vegetation of a mountain forest fragment with Juglans jamaicensis. Floristic composition, vegetation structure, and the index value of importance were evaluated. Diameter at 1.30 m above the ground and height of all trees greater than 5 cm in diameter was measured. Data were analyzed using canonical correspondence analysis. 776 individuals of 43 species and 41 genera belonging to 30 families, reporting the Rubiaceae family as the richest in species, followed by Amigdalaceae, Araliaceae, Cyatheaceae, Euphorbiaceae, Flacourtiaceae, Meliaceae, Moraceae, Sapindaceae and Poaceae. The tree species with more IVI were the Pseudolmedia spuria, Oxandra laurifolia, Trophis racemosa, Ocotea leucoxylon, Guarea guara, Dendropanax arboreus and Juglans jamaicensis, mainly due to its abundance in the vegetation, but it was found that the main contributor to the organic weight parameter species was the relative frequency.

  16. Study of a steel strand tension sensor with difference single bypass excitation structure based on the magneto-elastic effect

    International Nuclear Information System (INIS)

    Tang Dedong; Huang Shanglian; Chen Weimin; Jiang Jianshan

    2008-01-01

    With many steel strands used in various important machines and architectural structures, health monitoring of strand tension becomes more and more important to ensure the equipment or structures' safety. Contrasted with the method of vibration frequency and strain gages, the method of measuring the steel strand tension based on the magneto-elastic effect is more capable of meeting the requirements of health monitoring. Yet the structure of the sensor is mainly a sleeve structure, and the steel strand to be measured serves as the core of primary and secondary solenoids. This structure is very difficult to fix and maintain. On the other hand, a change of temperature will strongly affect measurement results, and experiments prove that temperature error compensation by using a temperature compensation curve is not effective enough. Therefore in this paper the principle of a cable tension sensor based on the magneto-elastic effect is expounded, the theory of temperature influence is explored, a difference structure by single bypass excitation is devised, its magnetic loop is analyzed, an experiment is designed, and experiments on temperature compensation and pulling tension are carried out. The experiment results indicated that the structure of the sensor is feasible, temperature errors can be compensated for automatically, after which temperature errors become less than 0.012 MPa °C −1 , and repeating errors of tension are less than 0.15%, which meet the measurement requirements

  17. Study of a steel strand tension sensor with difference single bypass excitation structure based on the magneto-elastic effect

    Science.gov (United States)

    Tang, Dedong; Huang, Shanglian; Chen, Weimin; Jiang, Jianshan

    2008-04-01

    With many steel strands used in various important machines and architectural structures, health monitoring of strand tension becomes more and more important to ensure the equipment or structures' safety. Contrasted with the method of vibration frequency and strain gages, the method of measuring the steel strand tension based on the magneto-elastic effect is more capable of meeting the requirements of health monitoring. Yet the structure of the sensor is mainly a sleeve structure, and the steel strand to be measured serves as the core of primary and secondary solenoids. This structure is very difficult to fix and maintain. On the other hand, a change of temperature will strongly affect measurement results, and experiments prove that temperature error compensation by using a temperature compensation curve is not effective enough. Therefore in this paper the principle of a cable tension sensor based on the magneto-elastic effect is expounded, the theory of temperature influence is explored, a difference structure by single bypass excitation is devised, its magnetic loop is analyzed, an experiment is designed, and experiments on temperature compensation and pulling tension are carried out. The experiment results indicated that the structure of the sensor is feasible, temperature errors can be compensated for automatically, after which temperature errors become less than 0.012 MPa °C-1, and repeating errors of tension are less than 0.15%, which meet the measurement requirements.

  18. Structural Characterization of Doped GaSb Single Crystals by X-ray Topography

    Energy Technology Data Exchange (ETDEWEB)

    Honnicke, M.G.; Mazzaro, I.; Manica, J.; Benine, E.; M da Costa, E.; Dedavid, B. A.; Cusatis, C.; Huang, X. R.

    2009-09-13

    We characterized GaSb single crystals containing different dopants (Al, Cd and Te), grown by the Czochralski method, by x-ray topography and high angular resolution x-ray diffraction. Lang topography revealed dislocations parallel and perpendicular to the crystal's surface. Double-crystal GaSb 333 x-ray topography shows dislocations and vertical stripes than can be associated with circular growth bands. We compared our high-angular resolution x-ray diffraction measurements (rocking curves) with the findings predicted by the dynamical theory of x-ray diffraction. These measurements show that our GaSb single crystals have a relative variation in the lattice parameter ({Delta}d/d) on the order of 10{sup -5}. This means that they can be used as electronic devices (detectors, for example) and as x-ray monochromators.

  19. Polarization properties and crystal structures of ferroelectric (Ba,CaTiO3 single crystals

    Directory of Open Access Journals (Sweden)

    Ryota Imura

    2014-01-01

    Full Text Available We have investigated the spontaneous polarization (Ps of Ba1-xCaxTiO3 (BCT by polarization hysteresis measurements using single crystals and by density functional theory (DFT calculations. Single crystals of BCT (x = 0.07 were grown by a top-seeded solution growth (TSSG method. The polarization measurements show that the crystals (x = 0.07 have a Ps of 26.0 μC/cm2, which is slightly small compared with BaTiO3 (27.3 μC/cm2. Our DFT calculations based on a supercell approach show that Ca atoms are markedly displaced cooperatively with the adjacent Ti atoms along the Ps direction. It is suggested that the CaTiO3-like octahedral rotation is constructed in the BCT supercell around the Ca atoms, which is the origin of the smaller Ps observed for the BCT crystals.

  20. On the structure and dynamics of water associated with single-supported zwitterionic and anionic membranes

    DEFF Research Database (Denmark)

    Miskowiec, A.; Buck, Z. N.; Hansen, Flemming Yssing

    2017-01-01

    We have used high-resolution quasielastic neutron scattering (QENS) to investigate the dynamics of water molecules (time scale of motion similar to ∼10-11- 10-9 s) in proximity to single-supported bilayers of the zwitterionic lipid DMPC (1,2-dimyristoyl-sn-glycero-3-phosphorylcholine......) and the anionic lipid DMPG (1,2-dimyristoyl-sn-glycero-3-phosphoglycerol) in the temperature range 160-295 K. For both membranes, the temperature dependence of the intensity of neutrons scattered elastically and incoherently from these samples indicates a series of freezing/melting transitions...... present at temperatures below the freezing point of bulk-like water. We then go on to determine the temperature dependence of the translational diffusion coefficient of the water associated with single-supported DMPG membranes containing two different amounts of water as we have previously done for DMPC...

  1. Structural analysis of a composite continuous girder with a single rectangular web opening

    Directory of Open Access Journals (Sweden)

    Mohamed A. ElShaer

    2017-08-01

    In this paper, a non-linear finite element analysis has been done to analyze the deflection in the steel section and internal stresses in the concrete slab for continuous composite girders with a single rectangular opening in the steel web. ANSYS computer program (version 15 has been used to analyze the three-dimensional model. The reliability of the model was demonstrated by comparison with experimental results of continuous composite beams without an opening in the steel web carried out by another author. The parametric analysis was executed to investigate the width, height, and position of the opening in one span on the behavior of a composite girder under vertical load. The results indicated that when the width of opening is less than 0.05 of length of a single span and the height is less than 0.15 of the steel web, the deflection and internal stresses increased less than 10% comparing to continuous composite girders without an opening.

  2. Effect of zinc acetate addition on crystal growth, structural, optical, thermal properties of glycine single crystals

    Directory of Open Access Journals (Sweden)

    S. Anbu Chudar Azhagan

    2017-05-01

    Full Text Available In the present study, γ-glycine has been crystallized by using zinc acetate dihydrate as an additive for the first time by slow solvent evaporation method. The second harmonic conversion efficiency of γ-glycine crystal was determined using Kurtz and Perry powder technique and was found to be 3.66 times greater than that of standard inorganic material potassium dihydrogen phosphate (KDP. The analytical grade chemicals of glycine and zinc acetate dihydrate were taken in six different molar ratios: 1:0.2, 1:0.4, 1:0.6, 1:0.7, 1:0.8, and 1:0.9 respectively to find out the γ-polymorph of glycine. The lower molar concentration of zinc acetate yield only α-polymorph where as the higher molar concentration of zinc acetate inhibits the γ-polymorph of glycine which was confirmed by single crystal XRD and powder XRD studies. Inductively coupled plasma optical emission spectrometry (ICP-OES was carried out to quantify the concentration of zinc element in the grown glycine single crystals. The concentration of zinc element in the presence of grown γ-glycine single crystal is found to be 0.73 ppm. UV–Visible–NIR transmittance spectra were recorded for the samples to analyse the transparency in visible and near infrared region (NIR. The optical band gap Eg was estimated for γ-glycine single crystal using UV–Visible–NIR study. Functional groups present in the samples were identified by FTIR spectroscopic analysis. Differential scanning calorimetry technique was employed to determine the phase transition, thermal stability and melting point of the grown crystal.

  3. Structure and Characterization of Vertically Aligned Single-Walled Carbon Nanotube Bundles

    International Nuclear Information System (INIS)

    Marquez, F.; Morant, C.; Elizalde, E.; Roque-Malherbe, R.; Lopez, V.; Zamora, F.; Domingo, C.

    2010-01-01

    Arrays of vertically aligned single-walled carbon nanotube bundles, SWCNTs, have been synthesized by simple alcohol catalytic chemical vapor deposition process, carried out at 800 degree C. The formed SWCNTs are organized in small groups perpendicularly aligned and attached to the substrate. These small bundles show a constant diameter of ca. 30 nm and are formed by the adhesion of no more than twenty individual SWCNTs perfectly aligned along their length.

  4. A Control Source Structure of Single Loudspeaker and Rear Sound Interference for Inexpensive Active Noise Control

    Directory of Open Access Journals (Sweden)

    Yasuhide Kobayashi

    2010-01-01

    phase-lag is imposed by the Swinbanks' source and the rear sound interference. Thirdly, effects on control performances of control source structures are examined by control experiments with robust controllers.

  5. Single-step antibody-based affinity cryo-electron microscopy for imaging and structural analysis of macromolecular assemblies.

    Science.gov (United States)

    Yu, Guimei; Vago, Frank; Zhang, Dongsheng; Snyder, Jonathan E; Yan, Rui; Zhang, Ci; Benjamin, Christopher; Jiang, Xi; Kuhn, Richard J; Serwer, Philip; Thompson, David H; Jiang, Wen

    2014-07-01

    Single particle cryo-electron microscopy (cryo-EM) is an emerging powerful tool for structural studies of macromolecular assemblies (i.e., protein complexes and viruses). Although single particle cryo-EM requires less concentrated and smaller amounts of samples than X-ray crystallography, it remains challenging to study specimens that are low-abundance, low-yield, or short-lived. The recent development of affinity grid techniques can potentially further extend single particle cryo-EM to these challenging samples by combining sample purification and cryo-EM grid preparation into a single step. Here we report a new design of affinity cryo-EM approach, cryo-SPIEM, that applies a traditional pathogen diagnosis tool Solid Phase Immune Electron Microscopy (SPIEM) to the single particle cryo-EM method. This approach provides an alternative, largely simplified and easier to use affinity grid that directly works with most native macromolecular complexes with established antibodies, and enables cryo-EM studies of native samples directly from cell cultures. In the present work, we extensively tested the feasibility of cryo-SPIEM with multiple samples including those of high or low molecular weight, macromolecules with low or high symmetry, His-tagged or native particles, and high- or low-yield macromolecules. Results for all these samples (non-purified His-tagged bacteriophage T7, His-tagged Escherichiacoli ribosomes, native Sindbis virus, and purified but low-concentration native Tulane virus) demonstrated the capability of cryo-SPIEM approach in specifically trapping and concentrating target particles on TEM grids with minimal view constraints for cryo-EM imaging and determination of 3D structures. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Single cell electroporation for longitudinal imaging of synaptic structure and function in the adult mouse neocortex in vivo

    Directory of Open Access Journals (Sweden)

    Stephane ePages

    2015-04-01

    Full Text Available Longitudinal imaging studies of neuronal structures in vivo have revealed rich dynamics in dendritic spines and axonal boutons. Spines and boutons are considered to be proxies for synapses. This implies that synapses display similar dynamics. However, spines and boutons do not always bear synapses, some may contain more than one, and dendritic shaft synapses have no clear structural proxies. In addition, synaptic strength is not always accurately revealed by just the size of these structures. Structural and functional dynamics of synapses could be studied more reliably using fluorescent synaptic proteins as markers for size and function. These proteins are often large and possibly interfere with circuit development, which renders them less suitable for conventional transfection or transgenesis methods such as viral vectors, in utero electroporation and germline transgenesis. Single cell electroporation has been shown to be a potential alternative for transfection of recombinant fluorescent proteins in adult cortical neurons. Here we provide proof of principle for the use of single cell electroporation to express and subsequently image fluorescently tagged synaptic proteins over days to weeks in vivo.

  7. Octupole deformation in neutron-rich actinides and superheavy nuclei and the role of nodal structure of single-particle wavefunctions in extremely deformed structures of light nuclei

    Science.gov (United States)

    Afanasjev, A. V.; Abusara, H.; Agbemava, S. E.

    2018-03-01

    Octupole deformed shapes in neutron-rich actinides and superheavy nuclei as well as extremely deformed shapes of the N∼ Z light nuclei have been investigated within the framework of covariant density functional theory. We confirmed the presence of new region of octupole deformation in neutron-rich actinides with the center around Z∼ 96,N∼ 196 but our calculations do not predict octupole deformation in the ground states of superheavy Z≥slant 108 nuclei. As exemplified by the study of 36Ar, the nodal structure of the wavefunction of occupied single-particle orbitals in extremely deformed structures allows to understand the formation of the α-clusters in very light nuclei, the suppression of the α-clusterization with the increase of mass number, the formation of ellipsoidal mean-field type structures and nuclear molecules.

  8. The Effects of U.S. National Security Strategy on Force Structure and the National Industrial Base: 1945-1960

    Science.gov (United States)

    2014-05-22

    a withdrawal of these troops would lead to a communist takeover of the peninsula from both the Central Intelligence Agency (CIA, formerly the OSS...Korean revolts and bolster South Korean forces as an effective deterrent to a communist takeover there, General MacArthur recommended otherwise. He...Fifth Regimental Combat Team from South Korea to Hawaii .60 On 23 September 1949, Truman announced to the nation the successful development of a

  9. Irradiation of zinc single crystal with 500 keV singly-charged carbon ions: surface morphology, structure, hardness, and chemical modifications

    Science.gov (United States)

    Waqas Khaliq, M.; Butt, M. Z.; Saleem, Murtaza

    2017-07-01

    Cylindrical specimens of (1 0 4) oriented zinc single crystal (diameter  =  6 mm and length  =  5 mm) were irradiated with 500 keV C+1 ions with the help of a Pelletron accelerator. Six specimens were irradiated in an ultra-high vacuum (~10‒8 Torr) with different ion doses, namely 3.94  ×  1014, 3.24  ×  1015, 5.33  ×  1015, 7.52  ×  1015, 1.06  ×  1016, and 1.30  ×  1016 ions cm-2. A field emission scanning electron microscope (FESEM) was utilized for the morphological study of the irradiated specimens. Formation of nano- and sub-micron size rods, clusters, flower- and fork-like structures, etc, was observed. Surface roughness of the irradiated specimens showed an increasing trend with the ions dose. Energy dispersive x-ray spectroscopy (EDX) helped to determine chemical modifications in the specimens. It was found that carbon content varied in the range 22.86-31.20 wt.% and that oxygen content was almost constant, with an average value of 10.16 wt.%. The balance content was zinc. Structural parameters, i.e. crystallite size and lattice strain, were determined by Williamson-Hall analysis using x-ray diffraction (XRD) patterns of the irradiated specimens. Both crystallite size and lattice strain showed a decreasing trend with the increasing ions dose. A good linear relationship between crystallite size and lattice strain was observed. Surface hardness depicted a decreasing trend with the ions dose and followed an inverse Hall-Petch relation. FTIR spectra of the specimens revealed that absorption bands gradually diminish as the dose of singly-charged carbon ions is increased from 3.94  ×  1014 ions cm-1 to 1.30  ×  1016 ions cm-1. This indicates progressive deterioration of chemical bonds with the increase in ion dose.

  10. Structure-Processing-Property Interrelationships of Vapor Grown Carbon Nanofiber, Single-Walled Carbon Nanotube and Functionalized Single-Walled Carbon Nanotube - Polypropylene Nanocomposites

    Science.gov (United States)

    Radhakrishnan, Vinod Karumathil

    This dissertation describes the first use of a design of experiments approach to investigate the interrelationships between structure, processing, and properties of melt extruded polypropylene (PP) carbon nanomaterial composites. The effect of nanomaterial structure was evaluated by exploring the incorporation of vapor grown carbon nanofibers (VGCFs), or pristine or functionalized single-walled carbon nanotubes (SWNTs or C12SWNTs) in polypropylene, while the effect of processing was investigated by studying the influence of melt extrusion temperature, speed, and time. The nanomaterials and PP were combined by an initial mixing method prior to melt extrusion. The nanocomposite properties were characterized by a combination of morphological, rheological, and thermal methods. Preliminary investigations into the effects of the initial mixing method revealed that the distribution of nanomaterials obtained after the mixing had a considerable influence on the properties of the final melt extruded nanocomposite. Dry mixing (DM) resulted in minimal adhesion between nanomaterials and PP during initial mixing; the majority of nanomaterials descended to the bottom. Hot coagulation (HC) mixing resulted in extremely high degrees of interaction between the nanomaterials and PP chains. Rotary evaporation (RE) mixing resulted in nanomaterial distribution uniformity between that obtained from DM and HC. Employing design of experiments to investigate the effects of structure and processing conditions on melt extruded PP nanocomposite properties revealed several interesting effects. The effect of processing conditions varied depending on the degree of nanomaterial distribution in PP attained prior to melt processing. Increasing melt extrusion temperature increased the decomposition temperature (Td) of PP/C12SWNT obtained from HC mixing but decreased T d of PP/C12SWNT obtained from RE mixing. Higher melt extrusion screw speed, on the other hand, significantly improved the nanocomposite

  11. Tl{sub 10}Hg{sub 3}Cl{sub 16}: Single crystal growth, electronic structure and piezoelectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Khyzhun, O.Y., E-mail: khyzhun@ipms.kiev.ua [Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanivsky Street, 03142 Kyiv (Ukraine); Piasecki, M. [Institute of Physics, J.Dlugosz University Częstochowa, Armii Krajowej 13/15, Częstochowa PL-42-217 (Poland); Kityk, I.V. [Electrical Engineering Department, Częstochowa University Technology, Armii Krajowej 17, PL-42-200 Częstochowa (Poland); Luzhnyi, I. [Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanivsky Street, 03142 Kyiv (Ukraine); Fedorchuk, A.O. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, 50 Pekarska Street, 79010 Lviv (Ukraine); Fochuk, P.M. [Yuriy Fed’kovych Chernivtsi National University, 2 Kotziubynskoho Street, 58012 Chernivtsi (Ukraine); Levkovets, S.I. [Department of Inorganic and Physical Chemistry, Lesya Ukrainka Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine); Karpets, M.V. [Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanivsky Street, 03142 Kyiv (Ukraine); Parasyuk, O.V. [Department of Inorganic and Physical Chemistry, Lesya Ukrainka Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine)

    2016-10-15

    Single crystal of the ternary halide Tl{sub 10}Hg{sub 3}Cl{sub 16} was grown using Bridgman-Stockbarger method. For the Tl{sub 10}Hg{sub 3}Cl{sub 16} crystal, we have measured X-ray photoelectron spectra for both pristine and Ar{sup +} ion-bombarded surfaces and additionally investigated photoinduced piezoelectricity. Our data indicate that the Tl{sub 10}Hg{sub 3}Cl{sub 16} single crystal surface is very sensitive with respect to Ar{sup +} ion-bombardment. In particular, Ar{sup +} ion-bombardment with energy of 3.0 keV over 5 min at an ion current density of 14 μA/cm{sup 2} causes significant changes of the elemental stoichiometry of the Tl{sub 10}Hg{sub 3}Cl{sub 16} surface resulting in an abrupt decrease of the mercury content in the top surface layers of the studied single crystal. As a result of the treatment, the mercury content becomes nil in the top surface layers. In addition, the present XPS measurements allow for concluding about very low hygroscopicity of the Tl{sub 10}Hg{sub 3}Cl{sub 16} single crystal surface. The property is extremely important for the crystal handling in optoelectronic or nano-electronic devices working at ambient conditions. The photoinduced piezoelectricity has been explored for Tl{sub 10}Hg{sub 3}Cl{sub 16} depending on nitrogen (λ=371 nm) laser power density and temperature. - Graphical abstract: As-grown single crystal boule of Tl{sub 10}Hg{sub 3}Cl{sub 16}; dependence of the effective piezoelecric coefficient d{sub 33} versus the photoinducing nitrogen laser power density, I, at different temperatures, T; and packing of the polyhedra of halide atoms around Hg atoms in the Tl{sub 10}Hg{sub 3}Cl{sub 16} structure. - Highlights: • High-quality Tl{sub 10}Hg{sub 3}Cl{sub 16} single crystal has been grown by Bridgman-Stockbarger method. • Electronic structure of Tl{sub 10}Hg{sub 3}Cl{sub 16} is studied by the XPS method. • Tl{sub 10}Hg{sub 3}Cl{sub 16} single crystal surface is sensitive with respect to Ar{sup +} ion

  12. Structure and dynamics of an upland old- growth forest at Redwood National Park, California

    Science.gov (United States)

    van Mantgem, Philip J.; Stuart, John D.

    2011-01-01

    Many current redwood forest management targets are based on old-growth conditions, so it is critical that we understand the variability and range of conditions that constitute these forests. Here we present information on the structure and dynamics from six one-hectare forest monitoring plots in an upland old-growth forest at Redwood National Park, California. We surveyed all stems =20 cm DBH in 1995 and 2010, allowing us to estimate any systematic changes in these stands. Stem size distributions for all species and for redwood (Sequoia sempervirens (D. Don) Endl.) alone did not appreciably change over the 15 year observation interval. Recruitment and mortality rates were roughly balanced, as were basal area dynamics (gains from recruitment and growth versus losses from mortality). Similar patterns were found for Sequoia alone. The spatial structure of stems at the plots suggested a random distribution of trees, though the pattern for Sequoia alone was found to be significantly clumped at small scales (forests, including populations of Sequoia, have been generally stable over the past 15 years at this site, though it is possible that fire exclusion may be affecting recruitment of smaller Sequoia (forests that encourage uniform spatial arrangements do not appear to mimic current upland old-growth conditions.

  13. Aspen structure and variability in Rocky Mountain National Park, Colorado, USA

    Science.gov (United States)

    Kaye, Margot W.; Stohlgren, T.J.; Binkley, Dan

    2003-01-01

    Elk, fire and climate have influenced aspen populations in the Rocky Mountains, but mostly subjective studies have characterized these factors. A broad-scale perspective may shed new light on the status of aspen in the region. We collected field measurements of aspen (Populus tremuloides Michx.) patches encountered within 36 randomly located belt transects in 340 km2 of Rocky Mountain National Park, Colorado, to quantify the aspen population. Aspen covered 5.6% of the area in the transects, much more than expected based on previously collected remotely sensed data. The distribution and structure of aspen patches were highly heterogeneous throughout the study area. Of the 123 aspen patches encountered in the 238 ha surveyed, all but one showed signs of elk browsing or had conifer species mixed with the aspen stems. No significant difference occurred in aspen basal area, density, regeneration, browsing of regeneration and patch size, between areas of concentrated elk use (elk winter range) and areas of dispersed elk use (elk summer range). Two-thirds of the aspen patches were mixed with conifer species. We concluded that the population of aspen in our study area is highly variable in structure and that, at a landscape-scale, evidence of elk browsing is widespread but evidence of aspen decline is not.

  14. Morphological and structural characterization of single-crystal ZnO nanorod arrays on flexible and non-flexible substrates

    Directory of Open Access Journals (Sweden)

    Omar F. Farhat

    2015-03-01

    Full Text Available We report a facile synthesis of zinc oxide (ZnO nanorod arrays using an optimized, chemical bath deposition method on glass, PET and Si substrates. The morphological and structural properties of the ZnO nanorod arrays were investigated using various techniques such as field emission scanning electron microscopy (FESEM and X-ray diffraction (XRD measurements, which revealed the formation of dense ZnO nanorods with a single crystal, hexagonal wurtzite structure. The aspect ratio of the single-crystal ZnO nanorods and the growth rate along the (002 direction was found to be sensitive to the substrate type. The lattice constants and the crystallite size of the fabricated ZnO nanorods were calculated based on the XRD data. The obtained results revealed that the increase in the crystallite size is strongly associated with the growth conditions with a minor dependence on the type of substrate. The Raman spectroscopy measurements confirmed the existence of a compressive stress in the fabricated ZnO nanorods. The obtained results illustrated that the growth of high quality, single-crystal ZnO nanorods can be realized by adjusting the synthesis conditions.

  15. Focused-ion-beam overlay-patterning of three-dimensional diamond structures for advanced single-photon properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Qianqing; Liu, Dongqi; Liu, Gangqin; Chang, Yanchun; Li, Wuxia, E-mail: liwuxia@aphy.iphy.ac.cn, E-mail: czgu@aphy.iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Pan, Xinyu; Gu, Changzhi, E-mail: liwuxia@aphy.iphy.ac.cn, E-mail: czgu@aphy.iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100190 (China)

    2014-07-28

    Sources of single photons are of fundamental importance in many applications as to provide quantum states for quantum communication and quantum information processing. Color centers in diamond are prominent candidates to generate and manipulate quantum states of light, even at room temperature. However, the efficiency of photon collection of the color centers in bulk diamond is greatly reduced by refraction at the diamond/air interface. To address this issue, diamond structuring has been investigated by various methods. Among them, focused-ion-beam (FIB) direct patterning has been recognized as the most favorable technique. But it has been noted that diamond tends to present significant challenges in FIB milling, e.g., the susceptibility of forming charging related artifacts and topographical features. In this work, periodically-positioned-rings and overlay patterning with stagger-superimposed-rings were proposed to alleviate some problems encountered in FIB milling of diamond, for improved surface morphology and shape control. Cross-scale network and uniform nanostructure arrays have been achieved in single crystalline diamond substrates. High quality diamond solid immersion lens and nanopillars were sculptured with a nitrogen-vacancy center buried at the desired position. Compared with the film counterpart, an enhancement of about ten folds in single photon collection efficiency was achieved with greatly improved signal to noise ratio. All these results indicate that FIB milling through over-lay patterning could be an effective approach to fabricate diamond structures, potentially for quantum information studies.

  16. Ensembles generated from crystal structures of single distant homologues solve challenging molecular-replacement cases in AMPLE.

    Science.gov (United States)

    Rigden, Daniel J; Thomas, Jens M H; Simkovic, Felix; Simpkin, Adam; Winn, Martyn D; Mayans, Olga; Keegan, Ronan M

    2018-03-01

    Molecular replacement (MR) is the predominant route to solution of the phase problem in macromolecular crystallography. Although routine in many cases, it becomes more effortful and often impossible when the available experimental structures typically used as search models are only distantly homologous to the target. Nevertheless, with current powerful MR software, relatively small core structures shared between the target and known structure, of 20-40% of the overall structure for example, can succeed as search models where they can be isolated. Manual sculpting of such small structural cores is rarely attempted and is dependent on the crystallographer's expertise and understanding of the protein family in question. Automated search-model editing has previously been performed on the basis of sequence alignment, in order to eliminate, for example, side chains or loops that are not present in the target, or on the basis of structural features (e.g. solvent accessibility) or crystallographic parameters (e.g. B factors). Here, based on recent work demonstrating a correlation between evolutionary conservation and protein rigidity/packing, novel automated ways to derive edited search models from a given distant homologue over a range of sizes are presented. A variety of structure-based metrics, many readily obtained from online webservers, can be fed to the MR pipeline AMPLE to produce search models that succeed with a set of test cases where expertly manually edited comparators, further processed in diverse ways with MrBUMP, fail. Further significant performance gains result when the structure-based distance geometry method CONCOORD is used to generate ensembles from the distant homologue. To our knowledge, this is the first such approach whereby a single structure is meaningfully transformed into an ensemble for the purposes of MR. Additional cases further demonstrate the advantages of the approach. CONCOORD is freely available and computationally inexpensive, so

  17. Structural and magnetic transitions in spinel FeM n2O4 single crystals

    Science.gov (United States)

    Nepal, Roshan; Zhang, Qiang; Dai, Samuel; Tian, Wei; Nagler, S. E.; Jin, Rongying

    2018-01-01

    Materials that form the spinel structure are known to exhibit geometric frustration, which can lead to magnetic frustration as well. Through magnetization and neutron diffraction measurements, we find that FeM n2O4 undergoes one structural and two magnetic transitions. The structural transition occurs at Ts˜595 K from cubic at high temperatures to tetragonal at low temperatures. Two magnetic transitions are ferrimagnetic at TFI -1˜373 K and TFI -2˜50 K , respectively. Further investigation of the specific heat, thermal conductivity, and Seebeck coefficient confirms both magnetic transitions. Of particular interest is that there is a significant magnetic contribution to the low-temperature specific heat and thermal conductivity, providing a unique system to study heat transport by magnetic excitations.

  18. Temperature effects on the atomic structure and kinetics in single crystal electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gründer, Yvonne; Markovic, Nenad M.; Thompson, Paul; Lucas, Christopher A.

    2015-01-01

    The influence of temperature on the atomic structure at the electrochemical interface has been studied using in-situ surface x-ray scattering (SXS) during the formation of metal monolayers on a Au(111) electrode. For the surface reconstruction of Au(111), higher temperatures increase the mobility of surface atoms in the unreconstructed phase which then determines the surface ordering during the formation of the reconstruction. For the underpotential deposition (UPD) systems, the surface diffusion of the depositing metal adatoms is significantly reduced at low temperatures which results in the frustration of ordered structures in the case of Cu UPD, occurring on a Br-modified surface, and in the formation of a disordered Ag monolayer during Ag UPD. The results indicate that temperature changes affect the mass transport and diffusion of metal adatoms on the electrode surface. This demonstrates the importance of including temperature as a variable in studying surface structure and reactions at the electrochemical interface.

  19. Structural Design of Systems with Safe Behavior under Single and Multiple Faults

    DEFF Research Database (Denmark)

    Blanke, Mogens; Staroswiecki, Marcel

    2006-01-01

    Handling of multiple simultaneous faults is a complex issue in fault-tolerant control. The design task is particularly made difficult by to the numerous different cases that need be analyzed. Aiming at safe fault-handling, this paper shows how structural analysis can be applied to find...... the analytical redundancy relations for all relevant combinations of faults, and can cope with the complexity and size of a real system. Being essential for fault-tolerant control schemes that shall handle particular cases of faults/failures, fault isolation is addressed. The paper introduces an extension...... to structural analysis to disclose which faults could be isolated from a structural point of view using active fault isolation. Results from application on a marine control system illustrate the concepts....

  20. Structural profiling and biological performance of phospholipid-hyaluronan functionalized single-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Dvash, Ram; Khatchatouriants, Artium; Solmesky, Leonardo J

    2013-01-01

    In spite of significant insolubility and toxicity, carbon nanotubes (CNTs) erupt into the biomedical research, and create an increasing interest in the field of nanomedicine. Single-walled CNTs (SWCNTs) are highly hydrophobic and have been shown to be toxic while systemically administrated. Thus...... an inflammatory response in macrophages as evidenced by the cytokine profiling and the use of image-based high-content analysis approach in contrast to non-modified CNTs. In addition, systemic administration of CNT-PL-HA into healthy C57BL/6 mice did not alter the total number of leukocytes nor increased liver...

  1. Structure of single-wall carbon nanotubes purified and cut using polymer

    Science.gov (United States)

    Zhang, M.; Yudasaka, M.; Koshio, A.; Jabs, C.; Ichihashi, T.; Iijima, S.

    2002-01-01

    Following on from our previous report that a monochlorobenzene solution of polymethylmethacrylate is useful for purifying and cutting single-wall carbon nanotubes (SWNTs) and thinning SWNT bundles, we show in this report that polymer and residual amorphous carbon can be removed by burning in oxygen gas. The SWNTs thus obtained had many holes (giving them a worm-eaten look) and were thermally unstable. Such severe damage caused by oxidation is unusual for SWNTs; we think that they were chemically damaged during ultrasonication in the monochlorobenzene solution of polymethylmethacrylate.

  2. Fine Structure of the Low-Frequency Raman Phonon Bands of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Iliev, M. N.; Litvinchuk, A. P.; Arepalli, S.; Nikolaev, P.; Scott, C. D.

    1999-01-01

    The Raman spectra of singled-wall carbon nanotubes (SWNT) produced by laser and are process were studied between 5 and 500 kappa. The line width vs. temperature dependence of the low-frequency Raman bands between 150 and 200/ cm deviates from that expected for phonon decay through phonon-phonon scattering mechanism. The experimental results and their analysis provided convincing evidence that each of the low-frequency Raman lines is a superposition of several narrower Raman lines corresponding to tubes of nearly the same diameter. The application of Raman spectroscopy to probe the distribution of SWNT by both diameter and chirality is discussed.

  3. Hydrostratigraphic and structural controls on streamflow generation in the Chuska Mountains, Navajo Nation, AZ/NM

    Science.gov (United States)

    Tsinnajinnie, L.; Frisbee, M. D.; Wilson, J. L.

    2017-12-01

    A conceptual model of hydrostratigraphic and structural influences on 3D streamflow generation processes is tested in the Whiskey Creek watershed located in the Chuska Mountains of the Navajo Nation along the northern NM/AZ border. The role of hydrostratigraphy and structure in groundwater processes has been well studied. However, influences of heterogeneity due to geologic structure and stratigraphy of mountain blocks on 3D streamflow generation has received less attention. Three-dimensional flow in mountainous watersheds, such as Saguache Creek (CO) and Rio Hondo (NM), contributes significant amounts of groundwater from deep circulation to streamflow. This fully 3D conceptual model is fundamentally different than watersheds characterized as 2D, those dominated by surface and shallow subsurface runoff, because 3D watersheds can have much longer flowpaths and mean residence times (up to 1000s of years). In contrast to Saguache Creek (volcanic bedrock) and Rio Hondo (crystalline metamorphic), the bedrock geology of the watersheds draining the Chuska Mountains is primarily comprised of sedimentary bedrock capped by extrusive volcanics. We test this conceptual model using a combination of stream gauging, tritium analyses, and endmember mixing analysis (EMMA) on the general ion chemistry and stable isotope composition of water samples collected in 2013-2016. Springs that emerge from the Chuska Sandstone are tritium dead indicative of a large component of pre-bomb pulse water in discharge and deeper 3D flow. EMMA indicates that most streamflow is generated from groundwater emerging from the Chuska Sandstone. Gaining/losing conditions in Whiskey Creek are strongly related to hydrostratigraphy as evidenced by a transition from gaining conditions largely found in the Chuska Sandstone to losing conditions where the underlying Chinle Formation outcrops. Although tritium in Whiskey Creek suggests 3D interactions are present, hydrostratigraphic and structural controls may

  4. Structural, thermal and optical characterization of an organic NLO material—Benzaldehyde thiosemicarbazone monohydrate single crystals

    Science.gov (United States)

    Santhakumari, R.; Ramamurthi, K.

    2011-02-01

    Single crystals of the organic NLO material, benzaldehyde thiosemicarbazone (BTSC) monohydrate, were grown by slow evaporation method. Solubility of BTSC monohydrate was determined in ethanol at different temperatures. The grown crystals were characterized by single crystal X-ray diffraction analysis to determine the cell parameters and by FT-IR technique to study the presence of the functional groups. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. UV-vis-NIR spectrum shows excellent transmission in the region of 200-1100 nm. Theoretical calculations were carried out to determine the linear optical constants such as extinction coefficient and refractive index. Further the optical nonlinearities of BTSC have been investigated by Z-scan technique with He-Ne laser radiation of wavelength 632.8 nm. Mechanical properties of the grown crystal were studied using Vickers microhardness tester. Second harmonic generation efficiency of the powdered BTSC monohydrate was tested using Nd:YAG laser and it is found to be ˜5.3 times that of potassium dihydrogen orthophosphate.

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

    Directory of Open Access Journals (Sweden)

    Tiecke T.G.

    2013-08-01

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

  6. Structural, thermal, optical and nonlinear optical properties of ethylenediaminium picrate single crystals

    Science.gov (United States)

    Indumathi, C.; T. C., Sabari Girisun; Anitha, K.; Alfred Cecil Raj, S.

    2017-07-01

    A new organic optical limiting material, ethylenediaminium picrate (EDAPA) was synthesized through acid base reaction and grown as single crystals by solvent evaporation method. Single crystal XRD analysis showed that EDAPA crystallizes in orthorhombic system with Cmca as space group. The formation of charge transfer complex during the reaction of ethylenediamine and picric acid was strongly evident through the recorded Fourier Transform Infra Red (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectrum. Thermal (TG-DTA and DSC) curves indicated that the material possesses high thermal stability with decomposition temperature at 243 °C. Optical (UV-Visible-NIR) analysis showed that the grown crystal was found to be transparent in the entire visible and NIR region. Z-scan studies with intense short pulse (532 nm, 5 ns, 100 μJ) excitations, revealed that EDAPA exhibited two photon absorption behaviour and the nonlinear absorption coefficient was found to be two orders of magnitude higher than some of the known optical limiter like Cu nano glasses. EDAPA exhibited a strong optical limiting action with low limiting threshold which make them a potential candidate for eye and photosensitive component protection against intense short pulse lasers.

  7. Microbial diversity structure in acetate single chamber microbial fuel cell for electricity generation

    Directory of Open Access Journals (Sweden)

    Dena Z. Khater

    2017-06-01

    Full Text Available This study investigates the performance of acetate feed membrane less single chamber microbial fuel cell and physical characterization of the bio film present on the anode surface using Scanning Electron Microscope (SEM and 16S rRNA analyzer. The performance has been investigated using Teflon treated carbon paper with 0.3 mg/cm2 Pt/C loaded as a cathode and carbon paper as an anode. The maximum open circuit potential is noticed as 791 mV, the system successfully revealed a maximum power density of 86.1 mW m−2 at stable current density of 354 mA m−2 with high coulombic efficiency of 65% at maximum degradation rate of 96%. SEM showed the dense adherence of microorganisms on the anode. 16S rRNA sequencing results indicates phylogenetic mixture in the communities of anodic biofilm and there is no single dominant bacterial species. The dominant phyla are Firmicutes, Gamma Proteobacteria, Alpha Proteobacteria, Actinobacteria, with ten dominant microbial strains: Bacillus firmus, Shewanella profunda, Bacillus isronensis, Brevundimonas bullata, Pseudomonas putida, Planococcus citreus, Micrococcus endophyticus, Acinetobacter tandoii, Bacillus safensis and Shewanella xiamenensis.

  8. Tuning the band structure and superconductivity in single-layer FeSe by interface engineering.

    Science.gov (United States)

    Peng, R; Xu, H C; Tan, S Y; Cao, H Y; Xia, M; Shen, X P; Huang, Z C; Wen, C H P; Song, Q; Zhang, T; Xie, B P; Gong, X G; Feng, D L

    2014-09-26

    The interface between transition metal compounds provides a rich playground for emergent phenomena. Recently, significantly enhanced superconductivity has been reported for single-layer FeSe on Nb-doped SrTiO3 substrate. Yet it remains mysterious how the interface affects the superconductivity. Here we use in situ angle-resolved photoemission spectroscopy to investigate various FeSe-based heterostructures grown by molecular beam epitaxy, and uncover that electronic correlations and superconducting gap-closing temperature (Tg) are tuned by interfacial effects. Tg up to 75 K is observed in extremely tensile-strained single-layer FeSe on Nb-doped BaTiO3, which sets a record high pairing temperature for both Fe-based superconductor and monolayer-thick films, providing a promising prospect on realizing more cost-effective superconducting device. Moreover, our results exclude the direct correlation between superconductivity and tensile strain or the energy of an interfacial phonon mode, and highlight the critical and non-trivial role of FeSe/oxide interface on the high Tg, which provides new clues for understanding its origin.

  9. Modelling of single walled carbon nanotube cylindrical structures with finite element method simulations

    Energy Technology Data Exchange (ETDEWEB)

    Günay, E. [Gazi University, Mechanical Engineering Department, 06570, Ankara (Turkey)

    2016-04-21

    In this study, the modulus of elasticity and shear modulus values of single-walled carbon nanotubes SWCNTs were modelled by using both finite element method and the Matlab code. Initially, cylindrical armchair and zigzag single walled 3D space frames were demonstrated as carbon nanostructures. Thereafter, macro programs were written by the Matlab code producing the space truss for zigzag and armchair models. 3D space frames were introduced to the ANSYS software and then tension, compression and additionally torsion tests were performed on zigzag and armchair carbon nanotubes with BEAM4 element in obtaining the exact values of elastic and shear modulus values. In this study, two different boundary conditions were tested and especially used in torsion loading. The equivalent shear modulus data was found by averaging the corresponding values obtained from ten different nodal points on the nanotube path. Finally, in this study it was determined that the elastic constant values showed proportional changes by increasing the carbon nanotube diameters up to a certain level but beyond this level these values remained stable.

  10. Modelling of single walled carbon nanotube cylindrical structures with finite element method simulations

    Science.gov (United States)

    Günay, E.

    2016-04-01

    In this study, the modulus of elasticity and shear modulus values of single-walled carbon nanotubes SWCNTs were modelled by using both finite element method and the Matlab code. Initially, cylindrical armchair and zigzag single walled 3D space frames were demonstrated as carbon nanostructures. Thereafter, macro programs were written by the Matlab code producing the space truss for zigzag and armchair models. 3D space frames were introduced to the ANSYS software and then tension, compression and additionally torsion tests were performed on zigzag and armchair carbon nanotubes with BEAM4 element in obtaining the exact values of elastic and shear modulus values. In this study, two different boundary conditions were tested and especially used in torsion loading. The equivalent shear modulus data was found by averaging the corresponding values obtained from ten different nodal points on the nanotube path. Finally, in this study it was determined that the elastic constant values showed proportional changes by increasing the carbon nanotube diameters up to a certain level but beyond this level these values remained stable.

  11. Modelling of single walled carbon nanotube cylindrical structures with finite element method simulations

    International Nuclear Information System (INIS)

    Günay, E.

    2016-01-01

    In this study, the modulus of elasticity and shear modulus values of single-walled carbon nanotubes SWCNTs were modelled by using both finite element method and the Matlab code. Initially, cylindrical armchair and zigzag single walled 3D space frames were demonstrated as carbon nanostructures. Thereafter, macro programs were written by the Matlab code producing the space truss for zigzag and armchair models. 3D space frames were introduced to the ANSYS software and then tension, compression and additionally torsion tests were performed on zigzag and armchair carbon nanotubes with BEAM4 element in obtaining the exact values of elastic and shear modulus values. In this study, two different boundary conditions were tested and especially used in torsion loading. The equivalent shear modulus data was found by averaging the corresponding values obtained from ten different nodal points on the nanotube path. Finally, in this study it was determined that the elastic constant values showed proportional changes by increasing the carbon nanotube diameters up to a certain level but beyond this level these values remained stable.

  12. Synthesis and single crystal structure analysis of 3,3',5,5'-tetramethyl ...

    African Journals Online (AJOL)

    The asymmetric units consist of tetrahedral [CoCl4]2- anions and tetramethyl bipyrazolium [H2Me4bpz]2+ dications and one water molecule which are connected through N—H····Cl and N—H····O hydrogen bond networks in the crystal lattice. Keywords: Crystal structure, Hydrogen bond and crystal engineering ...

  13. Structure, single-particle and many-particle coefficients of Lennard ...

    Indian Academy of Sciences (India)

    The dynamics of atomic pairs in the short-time regime in liquid aluminium may be said to be governed by the potential of mean force, which depends on the static structure of liquid Al at all investigated temperatures. A polynomial dependence of on density and temperature was observed in contradiction to Arrhenius law.

  14. Recent insights from single-molecule studies into nucleosome structure and dynamics

    NARCIS (Netherlands)

    Ordu, O.; Lusser, A; Dekker, N.H.

    2016-01-01

    Eukaryotic DNA is tightly packed into a hierarchically ordered structure called chromatin in order to fit into the micron-scaled nucleus. The basic unit of chromatin is the nucleosome, which consists of a short piece of DNA wrapped around a core of eight histone proteins. In addition to their role

  15. 26 CFR 1.48-10 - Single purpose agricultural or horticultural structures.

    Science.gov (United States)

    2010-04-01

    ... structures. 1.48-10 Section 1.48-10 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... products such as flowers, vegetables, or fruit) in a greenhouse. (ii) The commercial production of... facility which qualified for the credit when it was placed in service cannot later be modified and used for...

  16. Structural dynamics of green fluorescent protein alone and fused with a single chain Fv protein

    NARCIS (Netherlands)

    Hink, M.A.; Griep, R.A.; Borst, J.W.; Hoek, van A.; Eppink, M.H.M.; Schots, A.; Visser, A.J.W.G.

    2000-01-01

    Structural information on intracellular fusions of the green fluorescent protein (GFP) of the jellyfish Aequorea victoria with endogenous proteins is required as they are increasingly used in cell biology and biochemistry. We have investigated the dynamic properties of GFP alone and fused to a

  17. Magnetic, Structural, and Particle Size Analysis of Single- and Multi-Core Magnetic Nanoparticles

    DEFF Research Database (Denmark)

    Ludwig, Frank; Kazakova, Olga; Barquin, Luis Fernandez

    2014-01-01

    and the results are compared with each other. The presented results primarily focus on determining the particle size—both the hydrodynamic size and the individual magnetic core size—as well as magnetic and structural properties. The used analysis methods include transmission electron microscopy, static...

  18. Fabrication of 3D fractal structures using nanoscale anisotropic etching of single crystalline silicon

    NARCIS (Netherlands)

    Berenschot, Johan W.; Jansen, Henricus V.; Tas, Niels Roelof

    When it comes to high-performance filtration, separation, sunlight collection, surface charge storage or catalysis, the effective surface area is what counts. Highly regular fractal structures seem to be the perfect candidates, but manufacturing can be quite cumbersome. Here it is shown-–for the

  19. The effect of temperature on the deformation structure of single crystal nickel based superalloys

    Science.gov (United States)

    Dollar, M.; Bernstein, I. M.

    1988-01-01

    Results for the temperature dependence of the yield and flow stress were obtained for the superalloys PWA 1480 and CMSX-2. An extended Copley-Kear (1967) model is used to predict flow stresses from the dislocation densities measured at different strains and temperatures. Differences found between the two superalloys include the development of their dislocation structure, their ductility, and their work hardening characteristics.

  20. Electronic, structural, and substrate effect properties of single-layer covalent organic frameworks

    International Nuclear Information System (INIS)

    Liang, Liangbo; Zhu, Pan; Meunier, Vincent

    2015-01-01

    Recently synthesized two-dimensional covalent organic frameworks (COFs) exhibit high surface area, large pore size, and unique structural architectures, making them promising materials for various energy applications. Here, a total of nine COFs structures, including two deposited on a hexagonal boron nitride substrate, are investigated using density functional theory, quasi-particle many-body theory within the GW approximation, and an image charge model. The structures considered belong to two major families (thiophene-based COF-n (T-COF-n) and tetrakis (4-aminophenyl) porphyrin-x (TAPP-x)) differing from the presence of B—O or C=N linkers. While T-COF-n structures are shown to constitute planar networks, TAPP-x systems can display non-negligible corrugation due to the out-of-plane rotation of phenyl rings. We find that the electronic properties do not differ significantly when altering the chain molecules within each family. Many-body effects are shown to lead to large band-gap increase while the presence of the substrate yields appreciable reductions of the gaps, due to substrate polarization effects

  1. Structure, single-particle and many-particle coefficients of Lennard ...

    Indian Academy of Sciences (India)

    through migrations of atoms from the first shell in the pair distribution function. The dynamics of atomic pairs in the short-time regime in liquid aluminium may be said to be governed by the potential of mean force, which depends on the static structure of liquid Al at all investigated temperatures. A polynomial dependence of D ...

  2. Supranational Governance or National Business-As-Usual? The National Administration of EU Structural Funds in the Netherlands and Denmark

    DEFF Research Database (Denmark)

    Blom-Hansen, Jens; Yesilkagit, Kutsal

    2007-01-01

    that the multi-level governance literature and the critics of the multi-level governance framework have not examined implementation structures properly, but have focused on regional influence. We conduct a comparative analysis of the Dutch and Danish implementations of the European Social Fund and the European...... implementation structures of labour market policies and regional development. One central theoretical implication of our study is that the focus of studies of any fundamental re-allocation of power resources in cohesion studies should comprise the entire network of implementation rather than the strategies...

  3. Structure of radical pairs in irradiated single crystal of n-eicosane as studied by electron spin resonance

    International Nuclear Information System (INIS)

    Fujimura, T.; Tamura, N.

    1976-01-01

    The ESR spectra of a single crystal of n-eicosane have been analyzed. The angular dependence of the fine splitting in ΔM/sub s/=1 spectra reveals that several different radical pairs are produced in the single crystal of n-eicosane irradiated at 77 0 K. Five different pairs are clearly identified; they are interchain type. Among these five radical pairs four species are produced in the adjacent chains aligned along the b axis; their interspin distances are 4.42, 4.54, 5.22, and 5.33 A. One other is produced in the chains along the a axis and has the interspin distance of 4.25 A. The presence of the intrachain radical pairs (biradical) is also suggested. The structure of radical pair found in n-eicosane was compared with that found in oriented polyethylene

  4. Structure of BiRe2O6 re-investigated using single-crystal neutron Laue diffraction

    International Nuclear Information System (INIS)

    Sharma, N; Soehnel, T; McIntyre, G J; Piltz, R; Ling, C D

    2010-01-01

    Single crystals of BiRe 2 O 6 of typical volume 0.03 mm 3 were grown by chemical vapor transport and characterized using room-temperature single-crystal neutron diffraction in monoclinic C2/c symmetry with cell parameters a = 16.1178(11), b = 4.9235(3), c = 5.5278(3) A and β 92.475(5) 0 (R all = 11.39 wR all = 7.97). The structure contains ordered layers of corner sharing units of Re 2 O 10 with Re-Re distances of 2.519(1) A. The unit cell is doubled along c in comparison to previous studies based on X-ray diffraction data where the layer stacking was described as disorderd.

  5. Optical Sectioning and High Resolution in Single-Slice Structured Illumination Microscopy by Thick Slice Blind-SIM Reconstruction.

    Directory of Open Access Journals (Sweden)

    Aurélie Jost

    Full Text Available The microscope image of a thick fluorescent sample taken at a given focal plane is plagued by out-of-focus fluorescence and diffraction limited resolution. In this work, we show that a single slice of Structured Illumination Microscopy (two or three beam SIM data can be processed to provide an image exhibiting tight sectioning and high transverse resolution. Our reconstruction algorithm is adapted from the blind-SIM technique which requires very little knowledge of the illumination patterns. It is thus able to deal with illumination distortions induced by the sample or illumination optics. We named this new algorithm thick slice blind-SIM because it models a three-dimensional sample even though only a single two-dimensional plane of focus was measured.

  6. Photoluminescence and structural properties of unintentional single and double InGaSb/GaSb quantum wells grown by MOVPE

    Science.gov (United States)

    Ahia, Chinedu Christian; Tile, Ngcali; Botha, Johannes R.; Olivier, E. J.

    2018-04-01

    The structural and photoluminescence (PL) characterization of InGaSb quantum well (QW) structures grown on GaSb substrate (100) using atmospheric pressure Metalorganic Vapor Phase Epitaxy (MOVPE) is presented. Both structures (single and double-InGaSb QWs) were inadvertently formed during an attempt to grow capped InSb/GaSb quantum dots (QDs). In this work, 10 K PL peak energies at 735 meV and 740 meV are suggested to be emissions from the single and double QWs, respectively. These lines exhibit red shifts, accompanied by a reduction in their full-widths at half-maximum (FWHM) as the excitation power decreases. The presence of a GaSb spacer in the double QW was found to increase the strength of the PL emission, which consequently gives rise to a reduced blue-shift and broadening of the PL emission line observed for the double QW with an increase in laser power, while the low thermal activation energy for the quenching of the PL from the double QW is attributed to the existence of threading dislocations, as seen in the bright field TEM image for this sample.

  7. Structural and dynamic changes associated with beneficial engineered single-amino-acid deletion mutations in enhanced green fluorescent protein.

    Science.gov (United States)

    Arpino, James A J; Rizkallah, Pierre J; Jones, D Dafydd

    2014-08-01

    Single-amino-acid deletions are a common part of the natural evolutionary landscape but are rarely sampled during protein engineering owing to limited and prejudiced molecular understanding of mutations that shorten the protein backbone. Single-amino-acid deletion variants of enhanced green fluorescent protein (EGFP) have been identified by directed evolution with the beneficial effect of imparting increased cellular fluorescence. Biophysical characterization revealed that increased functional protein production and not changes to the fluorescence parameters was the mechanism that was likely to be responsible. The structure EGFP(D190Δ) containing a deletion within a loop revealed propagated changes only after the deleted residue. The structure of EGFP(A227Δ) revealed that a `flipping' mechanism was used to adjust for residue deletion at the end of a β-strand, with amino acids C-terminal to the deletion site repositioning to take the place of the deleted amino acid. In both variants new networks of short-range and long-range interactions are generated while maintaining the integrity of the hydrophobic core. Both deletion variants also displayed significant local and long-range changes in dynamics, as evident by changes in B factors compared with EGFP. Rather than being detrimental, deletion mutations can introduce beneficial structural effects through altering core protein properties, folding and dynamics, as well as function.

  8. First-principles study of structural and work function properties for nitrogen-doped single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Shao, Xiji; Li, Detian; Cai, Jianqiu; Luo, Haijun; Dong, Changkun

    2016-01-01

    Graphical abstract: - Highlights: • Substitutional nitrogen atom doping in capped (5, 5) SWNT is investigated. • Serious defects appear from breaks of C−N bonds with N contents of above 23.3 at.%. • Work function drops after N doping and may reach 4.1 eV. - Abstract: The structural and electronic properties of the capped (5, 5) single-walled carbon nanotube (SWNT), including the structural stability, the work function, and the charge transfer performance, are investigated for the substitutional nitrogen atom doping under different concentrations by first-principles density functional theory. The geometrical structure keeps almost intact with single or two N atom doping, while C−N bonds may break up with serious defects for N concentrations of 23.3 at.% and above. The SWNT remains metallic and the work function drops after doping due to the upward shift of Fermi level, leading to the increase of the electrical conductivity. N doping enhances the oxygen reduction activity stronger than N adsorption because of higher charge transfers.

  9. Single-particle cryo-EM using alignment by classification (ABC): the structure ofLumbricus terrestrishaemoglobin.

    Science.gov (United States)

    Afanasyev, Pavel; Seer-Linnemayr, Charlotte; Ravelli, Raimond B G; Matadeen, Rishi; De Carlo, Sacha; Alewijnse, Bart; Portugal, Rodrigo V; Pannu, Navraj S; Schatz, Michael; van Heel, Marin

    2017-09-01

    Single-particle cryogenic electron microscopy (cryo-EM) can now yield near-atomic resolution structures of biological complexes. However, the reference-based alignment algorithms commonly used in cryo-EM suffer from reference bias, limiting their applicability (also known as the 'Einstein from random noise' problem). Low-dose cryo-EM therefore requires robust and objective approaches to reveal the structural information contained in the extremely noisy data, especially when dealing with small structures. A reference-free pipeline is presented for obtaining near-atomic resolution three-dimensional reconstructions from heterogeneous ('four-dimensional') cryo-EM data sets. The methodologies integrated in this pipeline include a posteriori camera correction, movie-based full-data-set contrast transfer function determination, movie-alignment algorithms, (Fourier-space) multivariate statistical data compression and unsupervised classification, 'random-startup' three-dimensional reconstructions, four-dimensional structural refinements and Fourier shell correlation criteria for evaluating anisotropic resolution. The procedures exclusively use information emerging from the data set itself, without external 'starting models'. Euler-angle assignments are performed by angular reconstitution rather than by the inherently slower projection-matching approaches. The comprehensive 'ABC-4D' pipeline is based on the two-dimensional reference-free 'alignment by classification' (ABC) approach, where similar images in similar orientations are grouped by unsupervised classification. Some fundamental differences between X-ray crystallography versus single-particle cryo-EM data collection and data processing are discussed. The structure of the giant haemoglobin from Lumbricus terrestris at a global resolution of ∼3.8 Å is presented as an example of the use of the ABC-4D procedure.

  10. Novel structural features in two ZHX homeodomains derived from a systematic study of single and multiple domains

    Directory of Open Access Journals (Sweden)

    Owens Raymond J

    2010-05-01

    Full Text Available Abstract Background Zhx1 to 3 (zinc-fingers and homeoboxes form a set of paralogous genes encoding multi-domain proteins. ZHX proteins consist of two zinc fingers followed by five homeodomains. ZHXs have biological roles in cell cycle control by acting as co-repressors of the transcriptional regulator Nuclear Factor Y. As part of a structural genomics project we have expressed single and multi-domain fragments of the different human ZHX genes for use in structure determination. Results A total of 30 single and multiple domain ZHX1-3 constructs selected from bioinformatics protocols were screened for soluble expression in E. coli using high throughput methodologies. Two homeodomains were crystallized leading to structures for ZHX1 HD4 and ZHX2 HD2. ZHX1 HD4, although closest matched to homeodomains from 'homez' and 'engrailed', showed structural differences, notably an additional C-terminal helix (helix V which wrapped over helix I thereby making extensive contacts. Although ZHX2 HD2-3 was successfully expressed and purified, proteolysis occurred during crystallization yielding crystals of just HD2. The structure of ZHX2 HD2 showed an unusual open conformation with helix I undergoing 'domain-swapping' to form a homodimer. Conclusions Although multiple-domain constructs of ZHX1 selected by bioinformatics studies could be expressed solubly, only single homeodomains yielded crystals. The crystal structure of ZHX1 HD4 showed additional hydrophobic interactions relative to many known homeodomains via extensive contacts formed by the novel C-terminal helix V with, in particular, helix I. Additionally, the replacement of some charged covariant residues (which are commonly observed to form salt bridges in non-homeotherms such as the Drosophila 'engrailed' homeodomain, by apolar residues further increases hydrophobic contacts within ZHX1 HD4, and potentially stability, relative to engrailed homeodomain. ZHX1 HD4 helix V points away from the normally

  11. Annealing effect of H+ -implanted single crystal silicon on strain and crystal structure

    International Nuclear Information System (INIS)

    Duo Xinzhong; Liu Weili; Zhang Miao; Gao Jianxia; Fu Xiaorong; Lin Chenglu

    2000-01-01

    The work focuses on the rocking curves of H + -implanted single silicon crystal detected by Four-Crystal X-ray diffractometer. The samples were annealed under different temperatures. Lattice defect in H + -implanted silicon crystals was detected by Rutherford Backscattering Spectrometry. It appeared that H-related complex did not crush until annealing temperature reached about 400 degree C. At that temperature H 2 was formed, deflated in silicon lattice and strained the lattice. But defects did not come into being in large quantity. The lattice was undamaged. When annealing temperature reached 500 degree C, strain induced by H 2 deflation crashed the silicon lattice. A large number of defects were formed. At the same time bubbles in the crystal and blister/flaking on the surface could be observed

  12. Growth and electronic structure of single-layered transition metal dichalcogenides

    DEFF Research Database (Denmark)

    Dendzik, Maciej

    2016-01-01

    The discovery of graphene has opened a novel research direction focused on the properties of 2D materials. Transition metal dichalcogenides (TMDCs) were quickly identified as important materials due to the great variety of electronic properties that they manifest – properties that are markedly...... different from graphene’s. For example, semiconducting TMDCs undergo an indirectdirect band gap transition when thinned to a single layer (SL); this results in greatly enhanced photoluminescence, making those materials attractive for applications in optoelectronics. Furthermore, metallic TMDCs can host...... TMDCs is directly studied with angle-resolved photoemission spectroscopy (ARPES) and x-ray photoelectron spectroscopy (XPS) techniques. Experimental results are compared with density-functional theory calculations (DFT), both for a free-standing layer and for a layer adsorbed on a metallic substrate...

  13. Upgrade of neutron energy spectrometer with single multilayer bonner sphere using onion-like structure

    International Nuclear Information System (INIS)

    Mizukpshi, Tomoaki; Watanabe, Kenichi; Yamazaki, Atsushi; Uritan, Akira; Iguchi, Tetsuo; Ogata, Tomohiro; Muramatsu, Takashi

    2016-01-01

    In order to measure neutron energy spectra, the conventional Bonner Sphere Spectrometers (BSS) are widely used. In this spectrometer, several measurements with different size Bonner spheres are required. Operators should, therefore, place these spheres in several times to a measurement point where radiation dose might be relatively high. In order to reduce this effort, novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. Amount of LiF neutron converter is reduced near polar region, where the band-shaped detectors are concentrated, in order to uniform the directional sensitivity. The LiF-ZnS mixed powder has an advantage of extremely high light yield. However, since it is opaque, scintillation photons cannot be collect uniformly. This type of detector shows no characteristic shape in the pulse height spectrum. Subsequently, it is difficult to set the pulse height discrimination level. This issue causes sensitivity fluctuation due to gain instability of photodetectors and/or electric modules. In order to solve this problem, we propose to replace the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type LiCaAlF6 (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator and conducted basic experiments to evaluate the directional uniformity of the sensitivity. The fabricated detector shows excellent directional uniformity of the neutron sensitivity

  14. Upgrade of neutron energy spectrometer with single multilayer bonner sphere using onion-like structure

    Energy Technology Data Exchange (ETDEWEB)

    Mizukpshi, Tomoaki; Watanabe, Kenichi; Yamazaki, Atsushi; Uritan, Akira [Nagoya University, Nagoya (Japan); Iguchi, Tetsuo; Ogata, Tomohiro; Muramatsu, Takashi [Mitsubishi Heavy Industries Ltd., Kobe(Japan)

    2016-09-15

    In order to measure neutron energy spectra, the conventional Bonner Sphere Spectrometers (BSS) are widely used. In this spectrometer, several measurements with different size Bonner spheres are required. Operators should, therefore, place these spheres in several times to a measurement point where radiation dose might be relatively high. In order to reduce this effort, novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. Amount of LiF neutron converter is reduced near polar region, where the band-shaped detectors are concentrated, in order to uniform the directional sensitivity. The LiF-ZnS mixed powder has an advantage of extremely high light yield. However, since it is opaque, scintillation photons cannot be collect uniformly. This type of detector shows no characteristic shape in the pulse height spectrum. Subsequently, it is difficult to set the pulse height discrimination level. This issue causes sensitivity fluctuation due to gain instability of photodetectors and/or electric modules. In order to solve this problem, we propose to replace the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type LiCaAlF6 (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator and conducted basic experiments to evaluate the directional uniformity of the sensitivity. The fabricated detector shows excellent directional uniformity of the neutron sensitivity.

  15. Effect of chain stiffness on the structure of single-chain polymer nanoparticles

    DEFF Research Database (Denmark)

    Moreno, Angel J; Bacova, Petra; Lo Verso, Federica

    2018-01-01

    of the domains is in all cases similar to that of Gaussian chains or rings, irrespective of the stiffness and degree of cross-linking. It is the spatial arrangement of the domains which determines the global structure of the SCNP (sparse Gaussian-like object or crumpled globule). Since intramolecular stiffness...... or 'crumpled' globular behaviour for very stiff SCNPs. We characterize domains in the SCNPs. These are weakly deformable regions that can be seen as disordered analogues of domains in disordered proteins. Increasing stiffness leads to bigger and less deformable domains. Surprisingly, the scaling behaviour...... can be varied through the specific chemistry of the precursor or by introducing bulky side groups in its backbone, our results propose a new strategy to tune the global structure of SCNPs. ....

  16. Single- and multi-pulse formation of surface structures under static femtosecond irradiation

    Science.gov (United States)

    Guillermin, M.; Garrelie, F.; Sanner, N.; Audouard, E.; Soder, H.

    2007-07-01

    Femtosecond surface structure modifications are investigated under irradiation with laser pulses of 150 fs at 800 nm, on copper and silicon. We report sub-wavelength periodic structures formation (ripples) with a periodicity of 500 nm for both materials. These ripples are perpendicular to the laser polarization and can be obtained with only one pulse. The formation of these ripples corresponds to a fluence threshold of 1 J/cm 2 for copper and 0.15 J/cm 2 for silicon. We find several morphologies when more pulses are applied: larger ripples parallel to the polarization are formed with a periodicity of 1 μm and degenerate into a worm-like morphology with a higher number of pulses. In addition, walls of deep holes also show sub-wavelength and large ripples.

  17. Recursion method for the quasiparticle structure of a single vortex with induced magnetic order

    DEFF Research Database (Denmark)

    Udby, L.; Andersen, B.M.; Hedegård, P.

    2006-01-01

    . Furthermore, we study the low-energy quasiparticle structure when magnetic vortices operate as pinning centers for surrounding unidirectional spin density waves (stripes). We calculate the Fourier transformed LDOS and show how the energy dependence of relevant Fourier components can be used to determine...... the nature of the magnetic field-induced order, and predict field-induced LDOS features that can be tested by future scanning tunneling microscopy experiments....

  18. Single-particle effects in fine structure of super-asymmetric fission

    International Nuclear Information System (INIS)

    Mirea, M.

    1999-01-01

    Energy spectrum measurements concerning the 14 C decay from 223 Ra revealed a fine structure with an intense branch on the excited state of the daughter 209 Pb. Apart the great number of microscopic--macroscopic attempts of different authors in describing this behavior (compiled recently), this phenomenon was explained quantitatively using the Landau--Zener effect, i.e., the promotion mechanism of a unpaired nucleon between two levels characterised by the same quantum numbers connected to some symmetries of the nuclear system in the region where an avoided level crossing is exhibited. The adiabatic levels during the super-asymmetric fission process were determined with a new version of the two--centre shell model especially constructed for very large mass--asymmetries. The half--lives are obtained in the framework of the Wentzel--Kramers--Brillouin approximation. The amount of the variation of the barrier height in the excited channels was estimated accounting the specialization energy which can be interpreted as the excess of the energy of a nucleon with a given spin over the energy for the same spin nucleon state of lowest energy. It is evidenced that the fine structure of cluster decay is due to two competitive effects: the Landau--Zener effect which enhances the probability to have an excited daughter in the final channel and the specialization energy which increases the potential barrier and therefore leads to a diminution of the penetrability. This formalism was used for predictions of the fine structure in the case of 14 C decay of 225 Ac and to explain the fine structure of alpha decay. (author)

  19. Synthesis of NaCl Single Crystals with Defined Morphologies as Templates for Fabricating Hollow Nano/micro-structures

    DEFF Research Database (Denmark)

    Wang, B.B.; Jin, P.; Yue, Yuanzheng

    2015-01-01

    Hollow nanostructures have a wide range of applications in nanotechnology. To accurately fabricate such nanostructures, the first and common key step is to synthesize high quality templates with controlled symmetry and geometry, ideally through a green, efficient, and economical approach. However....... These naturally abundant NaCl single crystal templates are water-soluble, environmentally-friendly and uniform in both geometry and size, and hence are ideal for preparing high quality hollow nano/micro structures. The new approach may have the potential to replace the conventional hard or soft template...

  20. Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Joel Glenn [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

  1. [Association of the tagging single nucleotide polymorphisms in transforming growth factor beta-1 gene with hypertension in the Han nationality population in Xinjiang].

    Science.gov (United States)

    Yang, Jian-feng; Shi, Xiao-peng; Zhao, Dan; Deng, Feng-mei; Zhong, Hua; Wang, Gang; Wang, Zhen-huan; Chen, Xiong-ying; He, Fang

    2010-06-01

    Essential hypertension (EH) was a complex disease resulted from the interaction of cumulative effect of multiple genetic and environment factors. The relationship between the genetic polymorphisms in the transforming growth factor-beta1 (TGF-beta1), the blood levels and EH have been investigated, but the conclusions were different. Therefore, we investigate the relationship between the tagging single nucleotide polymorphisms (tSNPs) (rs1800469, rs2241716, rs11466345, rs2241715, rs4803455) in TGF-beta1 gene, blood levels and EH in the Han nationality population in Xinjiang, to clarity the pattern of linkage disequilibrium (LD) and the feature of the structure of haplotype. Based on the case-control study,we selected 732 (365 EH patients,367 controls) Han Chinese population from the Boertonggu countryside of Shawan region in the Xinjiang Uygur Autonomous Region of China by random cluster sampling. After questionnaire and physical examination, we collected blood samples, and the blood levels of TGF-beta1 were quantified using sandwich ELISA. The polymorphisms of TGF-beta1 gene in the study groups were detected with SNaPshot system. The case-control study in a large group was carried out separately for each of the tSNP and followed up by haplotypes analyses to determine the relation between tSNPs of TGF-beta1 gene and EH in the Han population. (1) The frequencies of alleles A, G of rs11466345 of TGF-beta1 gene in EH group and control group were as follows: 69.7%, 30.3%, 74.4%, 25.6%, respectively. It was demonstrated that the G allele of the rs11466345 polymorphism occurred at a significantly higher frequency in EH patients than in healthy controls (30.3% vs. 25.6%, P 0.05). (2)Except the site of rs11466345, the other tSNPs were in strong LD, and no statistical differences were observed in haplotypes distribution in the followup study between case-control groups (P > 0.05). (3) There were no difference of TGF-beta1 levels between the different genotypes and alleles in

  2. Detailed Investigation of the Structural, Thermal, and Electronic Properties of Gold Isocyanide Complexes with Mechano-Triggered Single-Crystal-to-Single-Crystal Phase Transitions.

    Science.gov (United States)

    Seki, Tomohiro; Sakurada, Kenta; Muromoto, Mai; Seki, Shu; Ito, Hajime

    2016-02-01

    Mechano-induced phase transitions in organic crystalline materials, which can alter their properties, have received much attention. However, most mechano-responsive molecular crystals exhibit crystal-to-amorphous phase transitions, and the intermolecular interaction patterns in the daughter phase are difficult to characterize. We have investigated phenyl(phenylisocyanide)gold(I) (1) and phenyl(3,5-dimethylphenylisocyanide)gold(I) (2) complexes, which exhibit a mechano-triggered single-crystal-to-single-crystal phase transition. Previous reports of complexes 1 and 2 have focused on the relationships between the crystalline structures and photoluminescence properties; in this work we have focused on other aspects. The face index measurements of complexes 1 and 2 before and after the mechano-induced phase transitions have indicated that they undergo non-epitaxial phase transitions without a rigorous orientational relationship between the mother and daughter phases. Differential scanning calorimetry analyses revealed the phase transition of complex 1 to be enthalpically driven by the formation of new aurophilic interactions. In contrast, the phase transition of complex 2 was found to be entropically driven, with the closure of an empty void in the mother phase. Scanning electron microscopy observation showed that the degree of the charging effect of both complexes 1 and 2 was changed by the phase transitions, which suggests that the formation of the aurophilic interactions affords more effective conductive pathways. Moreover, flash-photolysis time-resolved microwave conductivity measurements revealed that complex 1 increased in conductivity after the phase change, whereas the conductivity of complex 2 decreased. These contrasting results were explained by the different patterns in the aurophilic interactions. Finally, an intriguing disappearing polymorphism of complex 2 has been reported, in which a polymorph form could not be obtained again after some period of time

  3. Structural, mechanical and light yield characterisation of heat treated LYSO:Ce single crystals for medical imaging applications

    CERN Document Server

    Mengucci, P; Auffray, E; Barucca, G; Cecchi, C; Chipaux, R; Cousson, A; Davì, F; Di Vara, N; Rinaldi, D; Santecchia, E

    2015-01-01

    Five single crystals of cerium-doped lutetium yttrium oxyorthosilicate (LYSO:Ce) grown by the Czochralski method were submitted to structural characterisation by X-ray (XRD) and neutron (ND) diffraction, scanning (SEM) and transmission (TEM) electron microscopy and energy dispersive microanalysis (EDS). The Ultimate Tensile Strength (UTS), the Young Modulus (YM) and the Light Yield (LY) of the samples were also measured in order to correlate the mechanical and the optical behaviour of the crystals with the characteristics of their microstructure. Two of the samples analysed were also heat treated at 300 °C for 10 h to evidence possible variations induced by the temperature in the optical and mechanical response of the crystals. Results showed that the mean compositional variations evidenced by the structural analyses do not affect the mechanical and optical behaviour of the samples. On the contrary, the thermal treatment could induce the formation of coherent spherical particles (size 10 to 15 nm), not unifo...

  4. Correlation between crystal structure and mobility in organic field-effect transistors based on single crystals of tetrathiafulvalene derivatives.

    Science.gov (United States)

    Mas-Torrent, Marta; Hadley, Peter; Bromley, Stefan T; Ribas, Xavi; Tarrés, Judit; Mas, Montserrat; Molins, Elies; Veciana, Jaume; Rovira, Concepció

    2004-07-14

    Recently, it was reported that crystals of the organic material dithiophene-tetrathiafulvalene (DT-TTF) have a high field-effect charge carrier mobility of 1.4 cm(2)/(V x s). These crystals were formed by a simple drop-casting method, making this material interesting to investigate for possible applications in low-cost electronics. Here, organic single-crystal field-effect transistors based on materials related to DT-TTF are presented and a clear correlation between the crystal structure and the electrical characteristics is observed. The observed relationship between the mobilities in the different crystal structures is strongly corroborated by calculations of both the molecular reorganization energies and the maximum intermolecular transfer integrals. The most suitable materials described here exhibit mobilities that are among the highest reported for organic field-effect transistors and that are the highest reported for solution-processed materials.

  5. Online single particle measurements of black carbon coatings, structure and optical properties

    Science.gov (United States)

    Allan, James; Liu, Dantong; Taylor, Jonathan; Flynn, Michael; Williams, Paul; Morgan, William; Whitehead, James; Alfarra, Rami; McFiggans, Gordon; Coe, Hugh

    2016-04-01

    The impacts of black carbon on meteorology and climate remain a major source of uncertainty, owing in part to the complex relationship between the bulk composition of the particulates and their optical properties. A particular complication stems from how light interacts with particles in response to the microphysical configuration and any 'coatings', i.e. non-black carbon material that is either co-emitted or subsequently obtained through atmospheric processing. This may cause the particle to more efficiently absorb or scatter light and may even change the sign of its radiative forcing potential. While much insight has been gained through measurements of bulk aerosol properties, either while suspended or after collection on a filter or impactor substrate, this does not provide a complete picture and thus may not adequately constrain the system. Here we present an overview of recent work to better constrain the properties of black carbon using online, in situ measurements of single particles, primarily using a Single Particle Soot Photometer (SP2). We have developed novel methods of inverting the data produced and combining the different metrics derived so as to give the most effective insights into black carbon sources, processes and properties. We have also used this measurement in conjunction with other instruments (sometimes in series) and used the data to challenge many commonly used models of optical properties such as core-shell Mie, Rayleigh-Debeye-Gans and effective medium. This work has been carried out in a variety of atmospheric environments and with laboratory-produced soots, e.g. from a diesel engine rig. Highlights include the finding that with real-world atmospheric aerosols, bulk optical measurements may be insufficient to derive brown carbon parameters without detailed morphological data. We also show that the enhancement of absorption for both ambient and laboratory generated particles only occurs after the coating mass fraction reaches a certain

  6. On the structure and dynamics of water associated with single-supported zwitterionic and anionic membranes

    Science.gov (United States)

    Miskowiec, A.; Buck, Z. N.; Hansen, F. Y.; Kaiser, H.; Taub, H.; Tyagi, M.; Diallo, S. O.; Mamontov, E.; Herwig, K. W.

    2017-03-01

    We have used high-resolution quasielastic neutron scattering (QENS) to investigate the dynamics of water molecules (time scale of motion ˜10-11-10-9 s) in proximity to single-supported bilayers of the zwitterionic lipid DMPC (1,2-dimyristoyl-sn-glycero-3-phosphorylcholine) and the anionic lipid DMPG (1,2-dimyristoyl-sn-glycero-3-phosphoglycerol) in the temperature range 160-295 K. For both membranes, the temperature dependence of the intensity of neutrons scattered elastically and incoherently from these samples indicates a series of freezing/melting transitions of the membrane-associated water, which have not been observed in previous studies of multilayer membranes. We interpret these successive phase transitions as evidence of different types of water that are common to the two membranes and which are defined by their local environment: bulk-like water located furthest from the membrane and two types of confined water in closer proximity to the lipids. Specifically, we propose a water type termed "confined 2" located within and just above the lipid head groups of the membrane and confined 1 water that lies between the bulk-like and confined 2 water. Confined 1 water is only present at temperatures below the freezing point of bulk-like water. We then go on to determine the temperature dependence of the translational diffusion coefficient of the water associated with single-supported DMPG membranes containing two different amounts of water as we have previously done for DMPC. To our knowledge, there have been no previous studies comparing the dynamics of water in proximity to zwitterionic and anionic membranes. Our analysis of the water dynamics of the DMPG and DMPC membranes supports the classification of water types that we have inferred from their freezing/melting behavior. However, just as we observe large differences in the freezing/melting behavior between these model membranes for the same water type, our measurements demonstrate variation between these

  7. Community Structure of Macrozoobenthos in Mangrove Ecosystem, Kutai National Park, East Kalimantan

    Directory of Open Access Journals (Sweden)

    Anugrah A Budiarsa

    2014-05-01

    Full Text Available Mangrove forest in Kutai National Park (KNP is considered as nature-protected ecosystem. This forest ecosystem has high productivity ecosystem roles as feeding source, spawning and conservation area for water organism living in this surrounding area such as fishes, crustacean, mollusk and others. At the mangrove floor, mangrove is a benthic ecosystem that utilizes organic material either produced from mangrove itself or land sedimentation. This research was conducted using quadrant transect method with 10 observation stations. Collected data were identified, summed and analyzed. Community structure was analyzed by determining the diversity index, homogenous index and dominant index. The research showed that Makrozoobenthos found at the research location was 17 species which divided into 12 families and 3 classes. The smallest number was found in Lombok Bay (station number 8 with 6 species. The largest number was found in Perancis Cape (station number 9 with 15 species. The diversity index of community structure ranged from 1,7 to 2,4. This indicated that the community diversity was at moderate level (1,5

  8. The structural and compositional analysis of single crystal surfaces using low energy ion scattering

    International Nuclear Information System (INIS)

    Armour, D.G.; Van der Berg, J.A.; Verheij, IL.K.

    1979-01-01

    The use of ion scattering for surface composition and structure analysis has been reviewed. The extreme surface specificity of this technique has been widely used to obtain quitative information in a straightforward way, but the/aolc/currence of charge exchange processes, thermal lattice vibrations and multiple scattering have precluded quantitative analysis of experimental data. Examples are quoted to illustrate the progress that has been made in understanding these fundamental processes and in applying this knowledge to the development of the analytical capabilities of the technique. (author)

  9. Structural and electrical properties of organic stilbazolium single crystal of DSCHS

    Science.gov (United States)

    Sundaram, S. John; Raj, A. Antony; Ramaclus, Jerald V.; Sagayaraj, P.

    2016-05-01

    Organic nonlinear optical crystal 4-N, N-Dimethyl Amino-4'N'-Methyl-Stilbazolium 3-Carboxy-4-Hydroxy benzenesulfonate (DSCHS) has been successfully grown from aqueous methanol solution by adopting slow solvent evaporation technique. Chemical composition of the sample was confirmed by CHN analysis. Powder X-ray diffraction analysis was carried out and it shows that DSCHS crystal belongs to triclinic structure with Pl space group. It is found that this material exhibits positive photoconductivity. Dielectric studies were also carried out for different temperature by varying the frequency.

  10. Structural and electrical properties of organic stilbazolium single crystal of DSCHS

    International Nuclear Information System (INIS)

    Sundaram, S. John; Ramaclus, Jerald V.; Sagayaraj, P.; Raj, A. Antony

    2016-01-01

    Organic nonlinear optical crystal 4-N, N-Dimethyl Amino-4’N’-Methyl-Stilbazolium 3-Carboxy-4-Hydroxy benzenesulfonate (DSCHS) has been successfully grown from aqueous methanol solution by adopting slow solvent evaporation technique. Chemical composition of the sample was confirmed by CHN analysis. Powder X-ray diffraction analysis was carried out and it shows that DSCHS crystal belongs to triclinic structure with Pl space group. It is found that this material exhibits positive photoconductivity. Dielectric studies were also carried out for different temperature by varying the frequency.

  11. Assessment of Damage in Seismically Excited RC-Structures from a Single Measured Response

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Nielsen, Søren R. K.; Cakmak, A. S.

    1996-01-01

    for RC-frames which also admits an estimation of local damage. Based on the response time series calculated by the finite element programme, the corresponding local damages are next calculated by the present method. The method is investigated at different intensities of the earthquake and upon comparison...... with the finite element predictions it is found that the method is very efficient in localizing the damage when the damage level is sufficiently high. Furthermore, it has been experienced that the method seems to get slightly more inaccurate with increasingly structural complexity, i.e. the damage localization...

  12. Assessment of Damage in Seismically Excited RC-Structures from a Single Measured Response

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Nielsen, Søren R.K.; Cakmak, A. S.

    for RC-frames which also admits an estimation of local damage. Based on the response time series calculated by the finite element programme, the corresponding local damages are next calculated by the present method. The method is investigated at different intensities of the earthquake and upon comparison...... with the finite element predictions it is found that the method is very efficient in localizing the damage when the damage level is sufficiently high. Furthermore, it has been experienced that the method seems to get slightly more inaccurate with increasingly structural complexity, i.e. the damage localization...

  13. LBA-ECO CD-02 Forest Canopy Structure, Tapajos National Forest, Brazil: 1999-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports on Leaf Area Index (LAI) and Specific Leaf Area (SLA) measurements collected from forest and pasture sites in or near the Tapajos National...

  14. Comparison of single distance phase retrieval algorithms by considering different object composition and the effect of statistical and structural noise.

    Science.gov (United States)

    Chen, R C; Rigon, L; Longo, R

    2013-03-25

    Phase retrieval is a technique for extracting quantitative phase information from X-ray propagation-based phase-contrast tomography (PPCT). In this paper, the performance of different single distance phase retrieval algorithms will be investigated. The algorithms are herein called phase-attenuation duality Born Algorithm (PAD-BA), phase-attenuation duality Rytov Algorithm (PAD-RA), phase-attenuation duality Modified Bronnikov Algorithm (PAD-MBA), phase-attenuation duality Paganin algorithm (PAD-PA) and phase-attenuation duality Wu Algorithm (PAD-WA), respectively. They are all based on phase-attenuation duality property and on weak absorption of the sample and they employ only a single distance PPCT data. In this paper, they are investigated via simulated noise-free PPCT data considering the fulfillment of PAD property and weakly absorbing conditions, and with experimental PPCT data of a mixture sample containing absorbing and weakly absorbing materials, and of a polymer sample considering different degrees of statistical and structural noise. The simulation shows all algorithms can quantitatively reconstruct the 3D refractive index of a quasi-homogeneous weakly absorbing object from noise-free PPCT data. When the weakly absorbing condition is violated, the PAD-RA and PAD-PA/WA obtain better result than PAD-BA and PAD-MBA that are shown in both simulation and mixture sample results. When considering the statistical noise, the contrast-to-noise ratio values decreases as the photon number is reduced. The structural noise study shows that the result is progressively corrupted by ring-like artifacts with the increase of structural noise (i.e. phantom thickness). The PAD-RA and PAD-PA/WA gain better density resolution than the PAD-BA and PAD-MBA in both statistical and structural noise study.

  15. Electrospun single-walled carbon nanotube/polyvinyl alcohol composite nanofibers: structure-property relationships

    International Nuclear Information System (INIS)

    Naebe, Minoo; Lin Tong; Wang Xungai; Staiger, Mark P; Dai Liming

    2008-01-01

    Polyvinyl alcohol (PVA) nanofibers and single-walled carbon nanotube (SWNT)/PVA composite nanofibers have been produced by electrospinning. An apparent increase in the PVA crystallinity with a concomitant change in its main crystalline phase and a reduction in the crystalline domain size were observed in the SWNT/PVA composite nanofibers, indicating the occurrence of a SWNT-induced nucleation crystallization of the PVA phase. Both the pure PVA and SWNT/PVA composite nanofibers were subjected to the following post-electrospinning treatments: (i) soaking in methanol to increase the PVA crystallinity, and (ii) cross-linking with glutaric dialdehyde to control the PVA morphology. Effects of the PVA morphology on the tensile properties of the resultant electrospun nanofibers were examined. Dynamic mechanical thermal analyses of both pure PVA and SWNT/PVA composite electrospun nanofibers indicated that SWNT-polymer interaction facilitated the formation of crystalline domains, which can be further enhanced by soaking the nanofiber in methanol and/or cross-linking the polymer with glutaric dialdehyde

  16. Design, structural investigation and physicochemical properties of benzotriazolium m-nitrophthalate monohydrate single crystals

    Science.gov (United States)

    Mekala, R.; Mani, Rajaboopathi; Jagdish, P.; Mathammal, R.

    2018-04-01

    The single crystals of organic salt benzotriazolium m-nitrophthalate monohydrate were grown by slow evaporation technique. It crystallizes in orthorhombic system with space group Pbca. The molecular interactions of the compound have been pictured using Hirshfeld surfaces and fingerprints plots and the results were compared with BZD+·mNPA-. The functional groups were identified by FTIR and FT-Raman spectra. The proton transfer from acid to base was identified from the 1H and 13C NMR spectra. The absorption and emission spectrum of BTA+·mNPA-·H2O was recorded in aqueous solution and different solvents, respectively The HOMO and LUMO energy gap of benzotriazole and BTA+·mNPA-·H2O were calculated using density functional theory (DFT). The thermal stability and melting point of hydrated salt was analysed and compared by TG-DTG/DSC study. The anti-oxidant activity of the title compound was evaluated by DPPH and ABTS+ Radical scavenging assay. The anti-microbial and anti-cancer activity showed a potential impact in the crystal.

  17. Poly(ethylene oxide) Crystallization in Single Walled Carbon Nanotube Based Nanocomposites: Kinetics and Structural Consequences

    Energy Technology Data Exchange (ETDEWEB)

    T Chatterjee; A Lorenzo; R Krishnamoorti

    2011-12-31

    The overall isothermal crystallization behavior of poly(ethylene oxide) (PEO) in single walled carbon nanotube (SWNT) based nanocomposites is studied with a focus on growth kinetics and morphological evolution of PEO using differential scanning calorimetry and in-situ small angle x-ray scattering measurements respectively. The characteristic time for crystallization of PEO increases due to the presence of lithium dodecyl sulfate (LDS) stabilized carbon nanotubes. Further, analysis of crystallization data using the Lauritzen-Hoffman regime theory of crystal growth shows the PEO chains stiffen in presence of LDS with an increased energy barrier associated with the nucleation and crystal growth, and the nanotubes further act as a barrier to chain transport or enhance the efficacy of the LDS action. The energy penalty and diffusional barrier to chain transport in the nanocomposites disrupt the crystalline PEO helical conformation. This destabilization leads to preferential growth of local nuclei resulting in formation of thinner crystal lamellae and suggests that the crystallization kinetics is strongly affected by the nucleation and crystal growth events. This study is particularly interesting considering the suppression of the PEO crystallinity in presence of small fraction of Lithium ion based surfactant and carbon nanotubes.

  18. Investigating single-particle structure in 26Na using the new SHARC array

    International Nuclear Information System (INIS)

    Wilson, G.L.; Catford, W.N.; Diget, C.Aa.

    2015-01-01

    The changing of the nuclear shells for light, neutron-rich nuclei, and the single-particle nature of 26 Na, has been explored by studying 25 Na(d, p) 26 Na in inverse kinematics, using a beam of 25 Na ions at 5 MeV per nucleon, provided by the ISAC-II facility at TRIUMF, Vancouver. Charged particles were detected with a highly-segmented silicon array that surrounded the 0.5 mg/cm 2 (CD 2 ) n target. Gamma rays from the recoiling 26 Na nucleus were detected using eight Compton-suppressed HPGe clover detectors. Recoil tagging was provided by an in-beam scintillation foil, downstream of the germanium array. A novel technique of utilising pγ- and pγγ-gating to extract proton angular distributions from states populated close in energy was employed with success. New states in 26 Na that are populated directly have been identified, using γ-decay patterns. Shell model calculations for comparison to experimental results are ongoing, using different model bases. (author)

  19. Investigating Single-Particle Structure in 26Na Using the New SHARC Array

    Science.gov (United States)

    Wilson, G. L.; Catford, W. N.; Diget, C. Aa.; Orr, N. A.; Matta, A.; Hackman, G.; Williams, S. J.; Simpson, E. C.; Celik, I. C.; Achouri, N. L.; Adsley, P.; Al-Falou, H.; Ashley, R.; Austin, R. A. E.; Ball, G. C.; Blackmon, J. C.; Boston, A. J.; Boston, H. C.; Brown, S. M.; Cross, D. S.; Djongolov, M.; Drake, T. E.; Hager, U.; Fox, S. P.; Fulton, B. R.; Galinski, N.; Garnsworthy, A. B.; Jamieson, D.; Kanungo, R.; Leach, K.; Orce, J. N.; Pearson, C. J.; Porter-Peden, M.; Sarazin, F.; Sjue, S.; Smalley, D.; Sumithrarachchi, C.; Triambak, S.; Unsworth, C.; Wadsworth, R.

    The changing of the nuclear shells for light, neutron-rich nuclei, and the single-particle nature of 26Na, has been explored by studying 25Na(d, p)26Na in inverse kinematics, using a beam of 25Na ions at 5 MeV per nucleon, provided by the ISAC-II facility at TRIUMF, Vancouver. Charged particles were detected with a highly-segmented silicon array that surrounded the 0.5 mg/cm2 (CD2)n target. Gamma rays from the recoiling 26Na nucleus were detected using eight Compton-suppressed HPGe clover detectors. Recoil tagging was provided by an in-beam scintillation foil, downstream of the germanium array. A novel technique of utilising pγ- and pγγ-gating to extract proton angular distributions from states populated close in energy was employed with success. New states in 26Na that are populated directly have been identified, using γ-decay patterns. Shell model calculations for comparison to experimental results are ongoing, using different model bases.

  20. Inner structural vibration isolation method for a single control moment gyroscope

    Science.gov (United States)

    Zhang, Jingrui; Guo, Zixi; Zhang, Yao; Tang, Liang; Guan, Xin

    2016-01-01

    Assembling and manufacturing errors of control moment gyros (CMG) often generate high frequency vibrations which are detrimental to spacecrafts with high precision pointing requirement. In this paper, some design methods of vibration isolation between CMG and spacecraft is dealt with. As a first step, the dynamic model of the CMG with and without supporting isolation structures is studied and analyzed. Subsequently, the frequency domain analysis of CMG with isolation system is performed and the effectiveness of the designed system is ascertained. Based on the above studies, an adaptive design suitable with appropriate design parameters are carried out. A numerical analysis is also performed to understand the effectiveness of the system and the comparison made. The simulation results clearly indicate that when the ideal isolation structure was implemented in the spacecraft, the vibrations generated by the rotor were found to be greatly reduced, while the capacity of the output torque was not lost, which means that the isolation system will not affect the performance of attitude control.

  1. Surface Electronic Structure of Hybrid Organo Lead Bromide Perovskite Single Crystals

    KAUST Repository

    Komesu, Takashi

    2016-08-24

    The electronic structure and band dispersion of methylammonium lead bromide, CH3NH3PbBr3, has been investigated through a combination of angle-resolved photoemission spectroscopy (ARPES) and inverse photoemission spectroscopy (IPES), as well as theoretical modeling based on density functional theory. The experimental band structures are consistent with the density functional calculations. The results demonstrate the presence of a dispersive valence band in MAPbBr3 that peaks at the M point of the surface Brillouin zone. The results also indicate that the surface termination of the CH3NH3PbBr3 is the methylammonium bromide (CH3NH3Br) layer. We find our results support models that predict a heavier hole effective mass in the region of -0.23 to -0.26 me, along the Γ (surface Brillouin center) to M point of the surface Brillouin zone. The surface appears to be n-type as a result of an excess of lead in the surface region. © 2016 American Chemical Society.

  2. Structure and floristic composition of a tropical rain forest of the National Park Bari Catatumbo, Colombia

    International Nuclear Information System (INIS)

    Duenas, Ariel; Betancur, Julio; Galindo, Robinson

    2007-01-01

    The floristic composition and structure of a tropical wet forest in the Natural National Park Catatumbo Bari were characterized. This natural park is located in the Cordillera Oriental of Colombia, Norte de Santander, at 700 m altitude. All individuals with dbh ? 1 cm found in a 0.1 ha plot were sampled. We have found 636 individuals and 109 species with dbh? 1cm, and 432 individuals and 90 species with dbh ? 2.5 cm. The families with the highest number of species were Lauraceae (13), Rubiaceae (10), Melastomataceae (9), and Arecaceae (6). The genera with the higher number of species were Ocotea and Miconia (7), Psychotria (5), and Eschweilera, Inga and Piper (4). The majority of individuals and species corresponded to lowest height range and diametric class. The total basal area was 5.65 m . The most ecologically important species (highest IVI) were, in order, Trattinnickia cf. burserifolia, Calathea inocephala, Brownea ariza, Oenocarpus minor and Euterpe predatoria, and the families were Arecaceae, Rubiaceae, Burseraceae, Lauraceae and Moraceae. This is a relatively heterogeneous forest with low species richness, as a result of its past degradation.

  3. Using TOSCE (Team Objective Structured Clinical Examination in the second national medical sciences olympiad in Iran

    Directory of Open Access Journals (Sweden)

    Mitra Amini

    2012-01-01

    Full Text Available Introduction: Second National Medical Sciences Olympiad was done in Shiraz in August 2010 with aim of indentifying scientifically talented individuals, motivating students and orienting extracurricular activities. This Olympiad was done in 3 areas, basic sciences, clinical sciences and management. In clinical sciences, we used TOSCE (Team Objective Structured Clinical Examination. In this article we report the details of this exam and participants′ satisfaction. Materials and Methods: This Olympiad in Clinical Medical Sciences was held in 2 levels: Individual and team. In the team stage, 9 teams from 9 universities participated. We used TOSCE for measuring clinical competency of teams. Each team consisted of 3 students. We designed 12 stations based on emergency medicine in medical and surgical fields. The time considered for each station was 15 min, after doing this exam the view of students was measured using a valid and reliable questionnaire. Results: Most of the students believed that TOSCE was a useful examination for measuring competency. More than 50% of students reported that success in this exam needs clinical competency, team work and problem solving ability. Nearly, half (48.1% of students believed that 15 min is not enough for each station and they need more time. Conclusion: The results of this study showed that this kind of exam is useful for measuring clinical competency from students′ viewpoint .

  4. Structural Differentiation between Layered Single (Ni) and Double Metal Hydroxides (Ni–Al LDHs) Using Wavelet Transformation

    Energy Technology Data Exchange (ETDEWEB)

    Siebecker, Matthew G. [University of Delaware, Delaware Environmental Institute; Sparks, Donald L. [University of Delaware, Delaware Environmental Institute

    2017-09-07

    Layered double hydroxides (LDHs) are anionic clays important in disciplines such as environmental chemistry, geochemistry, and materials science. Developments in signal processing of extended X-ray absorption fine structure (EXAFS) data, such as wavelet transformation (WT), have been used to identify transition metals and Al present in the hydroxide sheets of LDHs. The WT plots of LDHs should be distinct from those of isostructural single metal hydroxides. However, no direct comparison of these minerals appears in the literature using WT. This work systematically analyzes a suite of Ni-rich mineral standards, including Ni–Al LDHs, single metal Ni hydroxides, and Ni-rich silicates using WT. The results illustrate that the WT plots for α-Ni(OH)2 and Ni–Al LDHs are often indistinguishable from each other, with similar two-component plots for the different mineral types. This demonstrates that the WT of the first metal shell often cannot be used to differentiate an LDH from a single metal hydroxide. Interlayer anions adsorbed to the hydroxide sheet of α-Ni(OH)2 affect the EXAFS spectra and are not visible in the FT but are clearly resolved and discrete in the WT.

  5. Growth of NBT-BT single crystals by flux method and their structural, morphological and electrical characterizations

    Science.gov (United States)

    Kanuru, Sreenadha Rao; Baskar, K.; Dhanasekaran, R.; Kumar, Binay

    2016-05-01

    In this paper, one of the important, eco-friendly polycrystalline material, (1-x)(Na0.5Bi0.5)TiO3 (NBT) - xBaTiO3 (BT) of different compositions (x=0.07, 0.06 and 0.05 wt%) around the morphotropic phase boundary (MPB) were synthesized by solid state reaction technique. And the single crystals with 13×7×7 mm3, 12×12×7 mm3 and 10×7×4 mm3 dimensions were grown by self flux method. The morphology, crystal structure and unit-cell parameters have been studied and the monoclinic phase has been identified for 0.07 wt% of BT. Higher BT concentration changes the crystal habit and the mechanism has been studied clearly. Raman spectroscopy at room-temperature confirms the presence of functional groups. The quality of the as grown single crystals was examined by high resolution x-ray diffraction analysis. The dielectric properties of the as grown crystals were investigated in the frequency range of 20 Hz-2 MHz from room temperature to 450 °C. The broad dielectric peak and frequency dispersion demonstrates the relaxor behavior of grown crystals. The dielectric constant (εr), transition temperature (Tm), and depolarization temperature (Td) of the grown crystals are found to be comparatively good. The diffusive factor (γ) from Curie-Weiss law confirms the as grown NBT-BT single crystals are relaxor in nature.

  6. Structure-Guided, Single-Point Modifications in the Phosphinic Dipeptide Structure Yield Highly Potent and Selective Inhibitors of Neutral Aminopeptidases

    Energy Technology Data Exchange (ETDEWEB)

    Vassiliou, Stamatia; Węglarz-Tomczak, Ewelina; Berlicki, Łukasz; Pawełczak, Małgorzata; Nocek, Bogusław; Mulligan, Rory; Joachimiak, Andrzej; Mucha, Artur

    2014-10-09

    Seven crystal structures of alanyl aminopeptidase from Neisseria meningitides (the etiological agent of meningitis, NmAPN) complexed with organophosphorus compounds were resolved to determine the optimal inhibitor-enzyme interactions. The enantiomeric phosphonic acid analogs of Leu and hPhe, which correspond to the P1 amino acid residues of well-processed substrates, were used to assess the impact of the absolute configuration and the stereospecific hydrogen bond network formed between the aminophosphonate polar head and the active site residues on the binding affinity. For the hPhe analog, an imperfect stereochemical complementarity could be overcome by incorporating an appropriate P1 side chain. The constitution of P1'-extended structures was rationally designed and the lead, phosphinic dipeptide hPhePψ[CH2]Phe, was modified in a single position. Introducing a heteroatom/heteroatom-based fragment to either the P1 or P1' residue required new synthetic pathways. The compounds in the refined structure were low nanomolar and subnanomolar inhibitors of N. meningitides, porcine and human APNs, and the reference leucine aminopeptidase (LAP). The unnatural phosphinic dipeptide analogs exhibited a high affinity for monozinc APNs associated with a reasonable selectivity versus dizinc LAP. Another set of crystal structures containing the NmAPN dipeptide ligand were used to verify and to confirm the predicted binding modes; furthermore, novel contacts, which were promising for inhibitor development, were identified, including a π-π stacking interaction between a pyridine ring and Tyr372.

  7. Machine learning of single molecule free energy surfaces and the impact of chemistry and environment upon structure and dynamics.

    Science.gov (United States)

    Mansbach, Rachael A; Ferguson, Andrew L

    2015-03-14

    The conformational states explored by polymers and proteins can be controlled by environmental conditions (e.g., temperature, pressure, and solvent) and molecular chemistry (e.g., molecular weight and side chain identity). We introduce an approach employing the diffusion map nonlinear machine learning technique to recover single molecule free energy landscapes from molecular simulations, quantify changes to the landscape as a function of external conditions and molecular chemistry, and relate these changes to modifications of molecular structure and dynamics. In an application to an n-eicosane chain, we quantify the thermally accessible chain configurations as a function of temperature and solvent conditions. In an application to a family of polyglutamate-derivative homopeptides, we quantify helical stability as a function of side chain length, resolve the critical side chain length for the helix-coil transition, and expose the molecular mechanisms underpinning side chain-mediated helix stability. By quantifying single molecule responses through perturbations to the underlying free energy surface, our approach provides a quantitative bridge between experimentally controllable variables and microscopic molecular behavior, guiding and informing rational engineering of desirable molecular structure and function.

  8. Chemical Structure, Ensemble and Single-Particle Spectroscopy of Thick-Shell InP-ZnSe Quantum Dots.

    Science.gov (United States)

    Reid, Kemar R; McBride, James R; Freymeyer, Nathaniel J; Thal, Lucas B; Rosenthal, Sandra J

    2018-02-14

    Thick-shell (>5 nm) InP-ZnSe colloidal quantum dots (QDs) grown by a continuous-injection shell growth process are reported. The growth of a thick crystalline shell is attributed to the high temperature of the growth process and the relatively low lattice mismatch between the InP core and ZnSe shell. In addition to a narrow ensemble photoluminescence (PL) line-width (∼40 nm), ensemble and single-particle emission dynamics measurements indicate that blinking and Auger recombination are reduced in these heterostructures. More specifically, high single-dot ON-times (>95%) were obtained for the core-shell QDs, and measured ensemble biexciton lifetimes, τ 2x ∼ 540 ps, represent a 7-fold increase compared to InP-ZnS QDs. Further, high-resolution energy dispersive X-ray (EDX) chemical maps directly show for the first time significant incorporation of indium into the shell of the InP-ZnSe QDs. Examination of the atomic structure of the thick-shell QDs by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) reveals structural defects in subpopulations of particles that may mitigate PL efficiencies (∼40% in ensemble), providing insight toward further synthetic refinement. These InP-ZnSe heterostructures represent progress toward fully cadmium-free QDs with superior photophysical properties important in biological labeling and other emission-based technologies.

  9. Thermal and structural performance of a single tube support post for the Superconducting Super Collider dipole magnet cryostat

    International Nuclear Information System (INIS)

    Boroski, W.N.; Nicol, T.H.; Ruschman, M.K.; Schoo, C.J.

    1993-07-01

    The reentrant support post currently incorporated in the Superconducting Super Collider (SSC) dipole cryostat has been shown to meet the structural and thermal requirements of the cryostat, both in prototype magnet assemblies and through component testing. However, the reentrant post design has two major drawbacks: tight dimensional control on all components, and cost driven by these tolerance constraints and a complex assembly procedure. A single tube support post has been developed as an alternative to the reentrant post design. Several prototype assemblies have been fabricated and subjected to structural testing. Compressive, tensile, and bending forces were applied to each assembly with deflection measured at several locations. A prototype support post has also been thermally evaluated in a heat leak measurement facility. Heat load to 4.2 K was measured with the intermediate post intercept operating at various temperatures while thermometers positioned along the conductive path of the post mapped thermal gradients. Results from these measurements indicate the single tube support post meets the design criteria for the SSC dipole magnet cryostat support system

  10. 3D spin-flop transition in enhanced 2D layered structure single crystalline TlCo2Se2

    Science.gov (United States)

    Jin, Z.; Xia, Z.-C.; Wei, M.; Yang, J.-H.; Chen, B.; Huang, S.; Shang, C.; Wu, H.; Zhang, X.-X.; Huang, J.-W.; Ouyang, Z.-W.

    2016-10-01

    The enhanced 2D layered structure single crystalline TlCo2Se2 has been successfully fabricated, which exhibits field-induced 3D spin-flop phase transitions. In the case of the magnetic field parallel to the c-axis (B//c), the applied magnetic field induces the evolution of the noncollinear helical magnetic coupling into a ferromagnetic (FM) state with all the magnetization of the Co ion parallel to the c-axis. A striking variation of the field-induced strain within the ab-plane is noticed in the magnetic field region of 20-30 T. In the case of the magnetic field perpendicular to the c-axis (B  ⊥  c), the inter-layer helical antiferromagnetic (AFM) coupling may transform to an initial canted AFM coupling, and then part of it transforms to an intermediate metamagnetic phase with the alignment of two-up-one-down Co magnetic moments and finally to an ultimate FM coupling in higher magnetic fields. The robust noncollinear AFM magnetic coupling is completely destroyed above 30 T. In combination with the measurements of magnetization, magnetoresistance and field-induced strain, a complete magnetic phase diagram of the TlCo2Se2 single crystal has been depicted, demonstrating complex magnetic structures even though the crystal geometry itself gives no indication of the magnetic frustration.

  11. Structural and magnetic investigations of single-crystalline neodymium zirconate pyrochlore Nd2Zr2O7

    Science.gov (United States)

    Hatnean, M. Ciomaga; Lees, M. R.; Petrenko, O. A.; Keeble, D. S.; Balakrishnan, G.; Gutmann, M. J.; Klekovkina, V. V.; Malkin, B. Z.

    2015-05-01

    We report structural and magnetic properties studies of large high-quality single crystals of the frustrated magnet Nd2Zr2O7 . Powder x-ray diffraction analysis confirms that Nd2Zr2O7 adopts the pyrochlore structure. Room-temperature x-ray diffraction and time-of-flight neutron-scattering experiments show that the crystals are stoichiometric in composition with no measurable site disorder. The temperature dependence of the magnetic susceptibility shows no magnetic ordering at temperatures down to 0.5 K. Fits to the magnetic susceptibility data using a Curie-Weiss law reveal a ferromagnetic coupling between the Nd moments. Magnetization versus field measurements show a local Ising anisotropy along the axes of the Nd3 + ions in the ground state. Specific heat versus temperature measurements in zero applied magnetic field indicate the presence of a thermal anomaly below T ˜7 K, but no evidence of magnetic ordering is observed down to 0.5 K. The experimental temperature dependence of the single-crystal bulk dc susceptibility and isothermal magnetization are analyzed using crystal field theory and the crystal field parameters and exchange coupling constants determined.

  12. Holography and coherent diffraction with low-energy electrons: A route towards structural biology at the single molecule level.

    Science.gov (United States)

    Latychevskaia, Tatiana; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner

    2015-12-01

    The current state of the art in structural biology is led by NMR, X-ray crystallography and TEM investigations. These powerful tools however all rely on averaging over a large ensemble of molecules. Here, we present an alternative concept aiming at structural analysis at the single molecule level. We show that by combining electron holography and coherent diffraction imaging estimations concerning the phase of the scattered wave become needless as the phase information is extracted from the data directly and unambiguously. Performed with low-energy electrons the resolution of this lens-less microscope is just limited by the De Broglie wavelength of the electron wave and the numerical aperture, given by detector geometry. In imaging freestanding graphene, a resolution of 2Å has been achieved revealing the 660.000 unit cells of the graphene sheet from a single data set. Once applied to individual biomolecules the method shall ultimately allow for non-destructive imaging and imports the potential to distinguish between different conformations of proteins with atomic resolution. Copyright © 2015. Published by Elsevier B.V.

  13. Effect of particle shape and structure on the results of single-particle light-scattering size analysis.

    Science.gov (United States)

    Umhauer, H; Bottlinger, M

    1991-11-20

    To evaluate quantitatively the influence exerted by the shape and structure of nonspherical, nonideal particles on the results of single-particle scattered-light size analysis, measurements were conducted with individual particles of different materials (glass, limestone, and quartz). For this purpose, the particles were suspended in an electrodynamic balance and repeatedly passed through the analyzer's measuring volume with a continually changing random orientation. The scattered-light signal spectra thus obtained specify the probability with which a certain pulse height is induced when the particle passes once through the measuring volume at a given coincidental orientation. The spectra reflect the material-characteristic influence. They allow the loss of resolution of common scattered-light size analyses to be assessed and algorithms (matrices) to be compiled with which the shape and structure influence may be mathematically eliminated. Because a shape and structure independent size parameter is also determined from the individual particles, exact calibration curves can be derived in which the shape and structure influence are incorporated.

  14. Fractal structures of single-walled carbon nanotubes in biologically relevant conditions: role of chirality vs. media conditions.

    Science.gov (United States)

    Khan, Iftheker A; Aich, Nirupam; Afrooz, A R M Nabiul; Flora, Joseph R V; Schierz, P Ariette; Ferguson, P Lee; Sabo-Attwood, Tara; Saleh, Navid B

    2013-11-01

    Aggregate structure of covalently functionalized chiral specific semiconducting single-walled carbon nanotubes (SWNTs) was systematically studied employing static light scattering (SLS). Fractal dimensions (Df) of two specific chirality SWNTs-SG65 and SG76 with (6, 5) and (7, 6) chiral enrichments-were measured under four biological exposure media conditions, namely: Dulbecco's Modified Eagle Medium (DMEM), Minimum Essential Medium (MEM), Roswell Park Memorial Institute (RPMI) 1640 medium, and 0.9% saline solution. The SWNTs exhibited chiral dependence on Df with SG65 showing more fractal or loosely bound aggregate structures, i.e., lower Df values (range of 2.24±0.03 to 2.64±0.05), compared to the SG76 sample (range of 2.58±0.13 to 2.90±0.08). All the Df values reported are highly reproducible, measured from multiple SLS runs and estimated with 'random block-effects' statistical analysis that yielded all p values to be fractal aggregates. Moreover, presence of fetal bovine serum (FBS) and bovine serum albumin (BSA), used to mimic the in vitro cell culture condition, reduced the Df values, i.e., created more fractal structures. Steric hindrance to aggregation was identified as the key mechanism for creating the fractal structures. Also, increase in FBS concentration from 1% to 10% resulted in increasingly lower Df values. Published by Elsevier Ltd.

  15. Pb1–xMnxTe single crystals and their structural properties

    Directory of Open Access Journals (Sweden)

    NEBOJSA ROMCEVIC

    2004-12-01

    Full Text Available Pb1-xMnxTe crystals were grown by the vertical Bridgman method. Their structural properties were observed both by optical microscopy after chemical polishing and ething, and by X-ray powder diffraction analysis. A solution of 5 vol. % Br2 in HBr at room temperatur, for an exposure of 2 min was determined for chemical polishing. A solution of 20 g KOH in 1 ml H2O2, 2 ml glycerol (C3H8O3, and 20 ml H2O at room temperature for an exposure for 6 min was found to be a suitable etching solution. The obtained results are discussed and compared with published data.

  16. Effects of Metal Ions on Conductivity and Structure of Single DNA Molecule in Different Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Dong Ruixin

    2010-01-01

    Full Text Available Abstract We design a novel nano-gap electrode to measure the current of DNA molecule, by which the current–voltage characteristics of individual native DNA, Ag-DNA and Ni-DNA molecules are obtained, respectively. The results show that the voltage gap of Ag- and Ni-DNA is higher than that of native DNA, and the conductance is lower than native DNA in neutral environment. The structure transition from B- to Z-DNA is observed in the presence of high concentrations of nickel ions and Ag-DNA appears chaos state by STM image and U-V spectra characterization. But in alkaline environment, the conductance of Ni-DNA rises and the voltage gap decreases with the increasing of nickel ion concentration denotes that the conductive ability of Ni-DNA is higher than that of native DNA.

  17. Single-field consistency relations of large scale structure part III: test of the equivalence principle

    Energy Technology Data Exchange (ETDEWEB)

    Creminelli, Paolo [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste, 34151 (Italy); Gleyzes, Jérôme; Vernizzi, Filippo [CEA, Institut de Physique Théorique, Gif-sur-Yvette cédex, F-91191 France (France); Hui, Lam [Physics Department and Institute for Strings, Cosmology and Astroparticle Physics, Columbia University, New York, NY, 10027 (United States); Simonović, Marko, E-mail: creminel@ictp.it, E-mail: jerome.gleyzes@cea.fr, E-mail: lhui@astro.columbia.edu, E-mail: msimonov@sissa.it, E-mail: filippo.vernizzi@cea.fr [SISSA, via Bonomea 265, Trieste, 34136 (Italy)

    2014-06-01

    The recently derived consistency relations for Large Scale Structure do not hold if the Equivalence Principle (EP) is violated. We show it explicitly in a toy model with two fluids, one of which is coupled to a fifth force. We explore the constraints that galaxy surveys can set on EP violation looking at the squeezed limit of the 3-point function involving two populations of objects. We find that one can explore EP violations of order 10{sup −3}÷10{sup −4} on cosmological scales. Chameleon models are already very constrained by the requirement of screening within the Solar System and only a very tiny region of the parameter space can be explored with this method. We show that no violation of the consistency relations is expected in Galileon models.

  18. The Study of Single Nb3Sn Quadrupole Coils Using a Magnetic Mirror Structure

    Energy Technology Data Exchange (ETDEWEB)

    Chlachidze, G.; Andreev, N.; Barzi, E.; Bossert, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, N.; Novitski, I.; Orris, D.; Tartaglia, M.

    2010-07-30

    Several 90-mm quadrupole coils made of 0.7-mm Nb{sub 3}Sn strand based on the 'Restack Rod Process' (RRP) of 108/127 design, with cored and non-cored cables and different cable insulation, were fabricated and individually tested at Fermilab using a test structure designed to provide a quadrupole magnetic field environment. The coils were instrumented with voltage taps and strain gauges to study quench performance and mechanical properties. The Nb{sub 3}Sn strand and cable parameters, the coil fabrication details, the mirror model assembly procedure and test results at temperatures of 4.5 K and 1.9 K are reported and discussed.

  19. Chromatic dispersion compensation and Coherent Direct-Sequence OCDMA operation on a single super structured FBG.

    Science.gov (United States)

    Baños, Rocío; Pastor, Daniel; Amaya, Waldimar; Garcia-Munoz, Victor

    2012-06-18

    We have proposed, fabricated and demonstrated experimentally a set of Coherent Direct Sequence-OCDMA en/decoders based on Super Structured Fiber Bragg Gratings (SSFBGs) which are able to compensate the fiber chromatic dispersion at the same time that they perform the en/decoding task. The proposed devices avoid the use of additional dispersion compensation stages reducing system complexity and losses. This performance was evaluated for 5.4, 11.4 and 16.8 km of SSMF. The twofold performance was verified in Low Reflectivity regime employing only one GVD compensating device at decoder or sharing out the function between encoder and decoder devices. Shared functionality requires shorter SSFBGs designs and also provides added flexibility to the optical network design. Moreover, dispersion compensated en/decoders were also designed into the High Reflectivity regime employing synthesis methods achieving more than 9 dB reduction of insertion loss for each device.

  20. New in protein structure and function annotation: hotspots, single nucleotide polymorphisms and the 'Deep Web'.

    Science.gov (United States)

    Bromberg, Yana; Yachdav, Guy; Ofran, Yanay; Schneider, Reinhard; Rost, Burkhard

    2009-05-01

    The rapidly increasing quantity of protein sequence data continues to widen the gap between available sequences and annotations. Comparative modeling suggests some aspects of the 3D structures of approximately half of all known proteins; homology- and network-based inferences annotate some aspect of function for a similar fraction of the proteome. For most known protein sequences, however, there is detailed knowledge about neither their function nor their structure. Comprehensive efforts towards the expert curation of sequence annotations have failed to meet the demand of the rapidly increasing number of available sequences. Only the automated prediction of protein function in the absence of homology can close the gap between available sequences and annotations in the foreseeable future. This review focuses on two novel methods for automated annotation, and briefly presents an outlook on how modern web software may revolutionize the field of protein sequence annotation. First, predictions of protein binding sites and functional hotspots, and the evolution of these into the most successful type of prediction of protein function from sequence will be discussed. Second, a new tool, comprehensive in silico mutagenesis, which contributes important novel predictions of function and at the same time prepares for the onset of the next sequencing revolution, will be described. While these two new sub-fields of protein prediction represent the breakthroughs that have been achieved methodologically, it will then be argued that a different development might further change the way biomedical researchers benefit from annotations: modern web software can connect the worldwide web in any browser with the 'Deep Web' (ie, proprietary data resources). The availability of this direct connection, and the resulting access to a wealth of data, may impact drug discovery and development more than any existing method that contributes to protein annotation.

  1. Structured oligonucleotides for target indexing to allow single-vessel PCR amplification and solid support microarray hybridization.

    Science.gov (United States)

    Girard, Laurie D; Boissinot, Karel; Peytavi, Régis; Boissinot, Maurice; Bergeron, Michel G

    2015-02-07

    The combination of molecular diagnostic technologies is increasingly used to overcome limitations on sensitivity, specificity or multiplexing capabilities, and provide efficient lab-on-chip devices. Two such techniques, PCR amplification and microarray hybridization are used serially to take advantage of the high sensitivity and specificity of the former combined with high multiplexing capacities of the latter. These methods are usually performed in different buffers and reaction chambers. However, these elaborate methods have high complexity and cost related to reagent requirements, liquid storage and the number of reaction chambers to integrate into automated devices. Furthermore, microarray hybridizations have a sequence dependent efficiency not always predictable. In this work, we have developed the concept of a structured oligonucleotide probe which is activated by cleavage from polymerase exonuclease activity. This technology is called SCISSOHR for Structured Cleavage Induced Single-Stranded Oligonucleotide Hybridization Reaction. The SCISSOHR probes enable indexing the target sequence to a tag sequence. The SCISSOHR technology also allows the combination of nucleic acid amplification and microarray hybridization in a single vessel in presence of the PCR buffer only. The SCISSOHR technology uses an amplification probe that is irreversibly modified in presence of the target, releasing a single-stranded DNA tag for microarray hybridization. Each tag is composed of a 3-nucleotide sequence-dependent segment and a unique "target sequence-independent" 14-nucleotide segment allowing for optimal hybridization with minimal cross-hybridization. We evaluated the performance of five (5) PCR buffers to support microarray hybridization, compared to a conventional hybridization buffer. Finally, as a proof of concept, we developed a multiplexed assay for the amplification, detection, and identification of three (3) DNA targets. This new technology will facilitate the design

  2. The effect of STDP temporal kernel structure on the learning dynamics of single excitatory and inhibitory synapses.

    Directory of Open Access Journals (Sweden)

    Yotam Luz

    Full Text Available Spike-Timing Dependent Plasticity (STDP is characterized by a wide range of temporal kernels. However, much of the theoretical work has focused on a specific kernel - the "temporally asymmetric Hebbian" learning rules. Previous studies linked excitatory STDP to positive feedback that can account for the emergence of response selectivity. Inhibitory plasticity was associated with negative feedback that can balance the excitatory and inhibitory inputs. Here we study the possible computational role of the temporal structure of the STDP. We represent the STDP as a superposition of two processes: potentiation and depression. This allows us to model a wide range of experimentally observed STDP kernels, from Hebbian to anti-Hebbian, by varying a single parameter. We investigate STDP dynamics of a single excitatory or inhibitory synapse in purely feed-forward architecture. We derive a mean-field-Fokker-Planck dynamics for the synaptic weight and analyze the effect of STDP structure on the fixed points of the mean field dynamics. We find a phase transition along the Hebbian to anti-Hebbian parameter from a phase that is characterized by a unimodal distribution of the synaptic weight, in which the STDP dynamics is governed by negative feedback, to a phase with positive feedback characterized by a bimodal distribution. The critical point of this transition depends on general properties of the STDP dynamics and not on the fine details. Namely, the dynamics is affected by the pre-post correlations only via a single number that quantifies its overlap with the STDP kernel. We find that by manipulating the STDP temporal kernel, negative feedback can be induced in excitatory synapses and positive feedback in inhibitory. Moreover, there is an exact symmetry between inhibitory and excitatory plasticity, i.e., for every STDP rule of inhibitory synapse there exists an STDP rule for excitatory synapse, such that their dynamics is identical.

  3. A Chrysodeixis chalcites single-nucleocapsid nucleopolyhedrovirus population from the Canary Islands is genotypically structured to maximize survival.

    Science.gov (United States)

    Bernal, Alexandra; Simón, Oihane; Williams, Trevor; Muñoz, Delia; Caballero, Primitivo

    2013-12-01

    A Chrysodeixis chalcites single-nucleocapsid nucleopolyhedrovirus wild-type isolate from the Canary Islands, Spain, named ChchSNPV-TF1 (ChchTF1-wt), appears to have great potential as the basis for a biological insecticide for control of the pest. An improved understanding of the genotypic structure of this wild-type strain population should facilitate the selection of genotypes for inclusion in a bioinsecticidal product. Eight genetically distinct genotypes were cloned in vitro: ChchTF1-A to ChchTF1-H. Quantitative real-time PCR (qPCR) analysis confirmed that ChchTF1-A accounted for 36% of the genotypes in the wild-type population. In bioassays, ChchTF1-wt occlusion bodies (OBs) were significantly more pathogenic than any of the component single-genotype OBs, indicating that genotype interactions were likely responsible for the pathogenicity phenotype of wild-type OBs. However, the wild-type population was slower killing and produced higher OB yields than any of the single genotypes alone. These results strongly suggested that the ChchTF1-wt population is structured to maximize its transmission efficiency. Experimental OB mixtures and cooccluded genotype mixtures containing the most abundant and the rarest genotypes, at frequencies similar to those at which they were isolated, revealed a mutualistic interaction that restored the pathogenicity of OBs. In OB and cooccluded mixtures containing only the most abundant genotypes, ChchTF1-ABC, OB pathogenicity was even greater than that of wild-type OBs. The ChchTF1-ABC cooccluded mixture killed larvae 33 h faster than the wild-type population and remained genotypically and biologically stable throughout five successive passages in vivo. In conclusion, the ChchTF1-ABC mixture shows great potential as the active ingredient of a bioinsecticide to control C. chalcites in the Canary Islands.

  4. Comparative evaluation of 2 g single dose versus conventional dose azithromycin in uncomplicated skin and skin structure infections.

    Science.gov (United States)

    Dey, Sudipta Kumar; Das, Amal Kanti; Sen, Sumit; Hazra, Avijit

    2015-01-01

    Uncomplicated skin and skin structure infections (uSSSIs) are a common clinical problem. Majority are caused by staphylococci and streptococci. Different oral antibiotics are used for uSSSI, with comparable efficacy but varying treatment duration, cost, and adverse event profile. Azithromycin is used in uSSSI in adults conventionally in a dose of 500 mg once for 5 days. The extensive tissue distribution of the drug and its long elimination half-life prompted us to explore whether a single 2 g dose of the drug would produce a response in uSSSI comparable to conventional dosing. We conducted a parallel group, open-label, randomized, controlled trial (CTRI/2015/07/005969) with subjects of either sex, ≥12 years of age, presenting with uSSSI to the dermatology outpatient department. One group (n = 146) received 2 g single supervised dose while the other (n = 146) received conventional dose of 500 mg once daily for 5 days. Subjects were followed up on day 4 and day 8. Complete clinical cure implied complete healing of lesions, without residual signs or symptoms, within 7 days. High cure rate was observed in both arms (97.97% and 98.63%, respectively) along with noticeable improvement in symptom profile from baseline but without statistically significant difference between groups. However, excellent adherence (defined as no tablets missed) was better in single dosing arm (98.65% vs. 86.30%). Tolerability was also comparable between groups with the majority of adverse events encountered being gastrointestinal in nature and mild. Single 2 g azithromycin dose achieved the same result as conventional azithromycin dosing in uSSSI with comparable tolerability but with the advantage of assured adherence. This dose can, therefore, be recommended as an alternative and administration supervised if feasible.

  5. Risk evaluation of embedded, single-walled liquid low-level waste piping at Oak Ridge National Laboratory. ESD Publication 4315

    International Nuclear Information System (INIS)

    1994-10-01

    Four categories of liquid low-level radioactive waste (LLLW) systems are defined in the Federal Facility Agreement (FFA) for the Oak Ridge Reservation (ORR). Categories A and B are new and fully compliant existing systems, respectively: Category C is singly contained and must be removed from service, and Category D is inactive. The FFA requires that secondary containment and leak detection be provided for all Category A and B piping in the LLLW System at Oak Ridge National Laboratory (ORNL); however, as noted in the D2 revision of the secondary containment design demonstration report (DOE 1994), some sections of single-walled embedded piping in Category B underground vaults at three ORNL facilities do not meet this requirement. A risk evaluation was performed in order compare the potential radiation dose to a member of the public that could result from a postulated leak in the single-walled pipes with projected radiation exposure to the workers who would modify the piping to meet FFA requirements. The risk to human health from replacing segments of embedded, single-walled piping in the LLW system is higher than the risk of leaving the piping as it is

  6. SU-E-P-19: A National Collaborative Academic Medical Physics Network: Structure, Activity and Outcomes

    International Nuclear Information System (INIS)

    Thwaites, D

    2015-01-01

    Purpose: A national Australian inter-university medical physics (MP) group was formed in 2011/12, supported by Department of Health Better Access to Radiation Oncology BARO) seed funding. Core membership includes the six universities providing postgraduate MP courses. Objectives include increasing capacity, development and efficiency of national academic MP structures/systems and hence supporting education, clinical training and research, for the MP workforce support. Although the BARO scheme focuses on Radiation Oncology, the group has wider MP interests. Methods: Two further BARO seed grants were achieved: 1) for networked academic activities, including shared-resource teaching, eg using virtual reality systems; MP outreach to schools and undergraduates; developing web-based student and registrar education/resources, etc.; and 2) for conjoint ‘translational research’ posts between universities and partner hospitals, to clinically progress advanced RT technologies and to support students and registrars. Each university received 0.5 FTE post from each grant over 2 years (total: $1.75M) and leveraged local additional partner funds. Results: Total funding: $4–5M. Overall there have been 35 (mainly overseas) postholders bringing specific expertise, beginning in early 2013. Periods in Australia have been from 0.25–2 years (median=1). As well as the education activities, research projects include lung/spine SBRT, 4D RT, FFF beams, technology assessment, complex treatment planning, imaging for radiation oncology, DIR, adaptive breast, datamining, radiomics,etc. Observed positive impacts include: increased interest in MP courses, training support, translational research infrastructure and/or clinical practice in the hospitals involved, plus increased collaboration and effectiveness between the universities. Posts are continuing beyond grant end using leveraged funds, providing the basis for sustainability of some posts. Conclusion: The BARO-funded projects have

  7. Synthesis, optical, structural, and electrical properties of single-crystalline CdS nanobelts

    Energy Technology Data Exchange (ETDEWEB)

    Alqahtani, Mohammed S. [King Saud University, Department of Physics and Astronomy, Riyadh (Saudi Arabia); Hadia, N.M.A.; Mohamed, S.H. [Sohag University, Physics Department, Faculty of Science, Sohag (Egypt)

    2017-04-15

    CdS nanobelts (NBs) were synthesized by vapor transport of CdS powders. The growth was carried out without any catalyst on quartz and Si (100) substrates. The synthesized CdS NBs were examined by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HR-TEM), X-ray powder diffraction (XRD), energy dispersion analysis of X-ray (EDAX), spectrophotometer, and photoluminescence spectroscopy. CdS NBs were indexed as hexagonal wurtzite structure. The growth was via vapor-solid growth mechanism and along the [100] direction. The refractive index was evaluated in the transparent region, as suggested by Swanepoel, using the envelope method. The refractive index values and the extinction coefficient were decreased by increasing the wavelength. The calculated optical band gap was 2.50 eV. The photoluminescence (PL) spectrum of the synthesized CdS NBs exhibited a green emission peak at 510 nm and a broad red emission peak at 696 nm. The conductivity measurements were achieved, in the temperature range from 300 to 600 K, using the conventional two-probe technique. Two different slopes with different activation energies of 0.618 and 0.215 eV were obtained. The CdS NBs are likely being novel functional materials. Thus, they can be used in the manufacture of innovative optoelectronic nanodevices. (orig.)

  8. The effects of diatom pore-size on the structures and extensibilities of single mucilage molecules.

    Science.gov (United States)

    Sanka, Immanuel; Suyono, Eko Agus; Alam, Parvez

    2017-08-07

    Diatoms secrete extracellular polymeric substances (EPS), or mucilage, around the cell wall that may serve to aid in motility and form a discrete layer that may help maintain thicker layers of EPS that have a greater role in adhesion. Mucilage molecules adhere to the diatom frustules, which are biosilica skeletons that develop from the diatom cell walls. Here, molecular dynamics methods were used to determine the characteristics of mucilage molecules as a function of pore size; notably 1,4-α-D-galacturonic acid, 1,4-β-glucuronic acid and 1,4-β-D-mannuronic acid. These uronic acids differ from each other in structure and extensibility as a function of their folding characteristics. Here, we find that when overlain upon a pore, mucilage molecules try to return to their native folded states but are restrained by their interactions with the silica surfaces. Furthermore, the extensibility of mucilage molecules over pore spaces affects the extent of mechanical energy required to straighten them. As such, different EPS molecules will affect sliding, friction and adhesion to subsequent layers of EPS in different ways. We conclude that higher EPS extensibility is homonymous with higher adhesive or frictive resistance since the molecules will be able to strain more before they reach the most extended (and thus rigid) conformation. The research herein is applicable to modern engineering as it yields insight into the biomimetic design of molecules and surfaces for improved adhesion or motility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Impact of African elephants on baobab (Adansonia digitata L.) population structure in northern Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Kupika, O.L.; Kativu, S.; Gandiwa, E.; Gumbie, A.

    2014-01-01

    The impact of African elephant (Loxodonta africana) on population structure of baobab trees (Adansonia digitata L.) was assessed in northern Gonarezhou National Park (GNP), southeast Zimbabwe. Baobabs were sampled in March 2008 and September 2012 using 11 randomly laid belt transects of variable

  10. Sex differences in sex drive, sociosexuality, and height across 53 nations: testing evolutionary and social structural theories.

    Science.gov (United States)

    Lippa, Richard A

    2009-10-01

    By analyzing cross-cultural patterns in five parameters--sex differences, male and female trait means, male and female trait standard deviations--researchers can better test evolutionary and social structural models of sex differences. Five models of biological and social structural influence are presented that illustrate this proposal. Using data from 53 nations and from over 200,000 participants surveyed in a recent BBC Internet survey, I examined cross-cultural patterns in these five parameters for two sexual traits--sex drive and sociosexuality--and for height, a physical trait with a biologically based sex difference. Sex drive, sociosexuality, and height all showed consistent sex differences across nations (mean ds = .62, .74, and 1.63). Women were consistently more variable than men in sex drive (mean female to male variance ratio = 1.64). Gender equality and economic development tended to predict, across nations, sex differences in sociosexuality, but not sex differences in sex drive or height. Parameters for sociosexuality tended to vary across nations more than parameters for sex drive and height did. The results for sociosexuality were most consistent with a hybrid model--that both biological and social structural influences contribute to sex differences, whereas the results for sex drive and height were most consistent with a biological model--that evolved biological factors are the primary cause of sex differences. The model testing proposed here encourages evolutionary and social structural theorists to make more precise and nuanced predictions about the patterning of sex differences across cultures.

  11. Variations in the Foraging Behaviour and Burrow Structures of the Damara Molerat Cryptomys damarensis in the Kalahari Gemsbok National Park

    Directory of Open Access Journals (Sweden)

    B.G. Lovegrove

    1987-10-01

    Full Text Available Aspects of two habitat-specific foraging behaviours of the social subterranean rodent Cryptomys damarensis, are discussed in terms of burrow structure, resource dispersion patterns, sand moisture content, burrow temperature regimes, and predatory pressures, in the Kalahari Gemsbok National Park, South Africa.

  12. Abundance and structure of African baobab (Adansonia digitata) across different soil types in Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Mashapa, C.; Zisadza-Gandiwa, P.; Gandiwa, E.; Kativu, S.

    2013-01-01

    This study investigated the abundance and structure of African baobab (Adansonia digitata) across soil group strata in Gonarezhou National Park, Zimbabwe. The study was based on a stratified random sampling design composed of the following soil group substrates: (i) granophyres, (ii) malvernia, and

  13. Reprocessing single-use cardiac catheters for interventional cardiology. A cost-minimization model for estimating potential saving at departmental scale and national level

    Directory of Open Access Journals (Sweden)

    Francesco Tessarolo

    2009-06-01

    Full Text Available

    Background: The utilization of single-use percutaneous catheters (SUDs is a common practice in interventional cardiology, but the increasing of cardiac interventions and the consequent economic load demand for assessing SUDs’ reuse. The study aimed at estimating the potential saving for Italian cardiology departments in the hypothesis that reprocessing and reuse of SUD is performed by guaranteeing safety and efficiency of the reconditioned device as high as the new marketed one.

    Methods: A cost-minimization model was applied from the perspective of the health national service. Input parameters for the model were settled by reviewing published data on technical, hygiene and functional properties of reprocessed electrophysiology (EP and percutaneous transluminal coronary angioplasty (PTCA catheters. Potential saving at department level was calculated as percentage of the actual expenditure for purchasing single-use devices. Two-ways sensitivity analysis was conducted on main cost drivers. Finally, saving at national level was estimated.

    Results: The revision of technical and safety data showed the feasibility of reprocessing and reuse of EP and PTCA catheters under determined constrains. Potential savings of 39%, and 12% were calculated at department level for EP and PTCA catheters, respectively. Sensitivity analysis showed saving was dependent primarily on departmental workload. Major variations in saving occurred in the range between one and 200 catheters per year. The cut-off between benefit and charges was also related to regeneration rate and maximum number of uses. The estimate of potential saving at national level ranged in the interval from €19.85M to €24.24M.

    Conclusions:When safety and efficiency is assured by certified reuse processing, substantial saving could be achieved both at departmental and national level contributing to optimize budget

  14. Redetermination of the crystal structure of β-zinc molybdate from single-crystal X-ray diffraction data.

    Science.gov (United States)

    Mtioui-Sghaier, Olfa; Mendoza-Meroño, Rafael; Ktari, Lilia; Dammak, Mohamed; García-Granda, Santiago

    2015-07-01

    The crystal structure of the β-polymorph of ZnMoO4 was re-determined on the basis of single-crystal X-ray diffraction data. In comparison with previous powder X-ray diffraction studies [Katikaneani & Arunachalam (2005 ▸). Eur. J. Inorg. Chem. pp. 3080-3087; Cavalcante et al. (2013 ▸). Polyhedron, 54, 13-25], all atoms were refined with anisotropic displacement parameters, leading to a higher precision with respect to bond lengths and angles. β-ZnMoO4 adopts the wolframite structure type and is composed of distorted ZnO6 and MoO6 octa-hedra, both with point group symmetry 2. The distortion of the octa-hedra is reflected by variation of bond lengths and angles from 2.002 (3)-2.274 (4) Å, 80.63 (11)-108.8 (2)° for equatorial and 158.4 (2)- 162.81 (14)° for axial angles (ZnO6), and of 1.769 (3)-2.171 (3) Å, 73.39 (16)-104.7 (2), 150.8 (2)-164.89 (15)° (MoO6), respectively. In the crystal structure, the same type of MO6 octa-hedra share edges to built up zigzag chains extending parallel to [001]. The two types of chains are condensed by common vertices into a framework structure. The crystal structure can alternatively be described as derived from a distorted hexa-gonally closed packed arrangement of the O atoms, with Zn and Mo in half of the octa-hedral voids.

  15. Improving the Reliability of Network Metrics in Structural Brain Networks by Integrating Different Network Weighting Strategies into a Single Graph

    Directory of Open Access Journals (Sweden)

    Stavros I. Dimitriadis

    2017-12-01

    Full Text Available Structural brain networks estimated from diffusion MRI (dMRI via tractography have been widely studied in healthy controls and patients with neurological and psychiatric diseases. However, few studies have addressed the reliability of derived network metrics both node-specific and network-wide. Different network weighting strategies (NWS can be adopted to weight the strength of connection between two nodes yielding structural brain networks that are almost fully-weighted. Here, we scanned five healthy participants five times each, using a diffusion-weighted MRI protocol and computed edges between 90 regions of interest (ROI from the Automated Anatomical Labeling (AAL template. The edges were weighted according to nine different methods. We propose a linear combination of these nine NWS into a single graph using an appropriate diffusion distance metric. We refer to the resulting weighted graph as an Integrated Weighted Structural Brain Network (ISWBN. Additionally, we consider a topological filtering scheme that maximizes the information flow in the brain network under the constraint of the overall cost of the surviving connections. We compared each of the nine NWS and the ISWBN based on the improvement of: (a intra-class correlation coefficient (ICC of well-known network metrics, both node-wise and per network level; and (b the recognition accuracy of each subject compared to the remainder of the cohort, as an attempt to access the uniqueness of the structural brain network for each subject, after first applying our proposed topological filtering scheme. Based on a threshold where the network level ICC should be >0.90, our findings revealed that six out of nine NWS lead to unreliable results at the network level, while all nine NWS were unreliable at the node level. In comparison, our proposed ISWBN performed as well as the best performing individual NWS at the network level, and the ICC was higher compared to all individual NWS at the node

  16. Energy gaps, electronic structures, and x-ray spectroscopies of finite semiconductor single-walled carbon nanotubes.

    Science.gov (United States)

    Gao, Bin; Jiang, Jun; Wu, ZiYu; Luo, Yi

    2008-02-28

    We report hybrid density functional theory calculations for electronic structures of hydrogen-terminated finite single-walled carbon nanotubes (6,5) and (8,3) up to 100 nm in length. Gap states that are mainly arisen from the hydrogen-terminated edges have been found in (8,3) tubes, but their contributions to the density of states become invisible when the tube is longer than 10 nm. The electronic structures of (6,5) and (8,3) tubes are found to be converged around 20 nm. The calculated band-gap energies of 100 nm long nanotubes are in good agreement with experimental results. The valence band structures of (6,5), (8,3), as well as (5,5) tubes are also investigated by means of ultraviolet photoelectron spectra (UPS), x-ray emission spectroscopy (XES), and the resonant inelastic x-ray scattering (RIXS) spectra theoretically. The UPS, XES and RIXS spectra become converged already at 10 nm. The length-dependent oscillation behavior is found in the RIXS spectra of (5,5) tubes, indicating that the RIXS spectra may be used to determine the size and length of metallic nanotubes. Furthermore, the chiral dependence observed in the simulated RIXS spectra suggests that RIXS spectra could be a useful technique for the determination of chirality of carbon nanotubes.

  17. Genomic variation and population structure detected by single nucleotide polymorphism arrays in Corriedale, Merino and Creole sheep

    Directory of Open Access Journals (Sweden)

    Andrés N Grasso

    2014-06-01

    Full Text Available The aim of this study was to investigate the genetic diversity within and among three breeds of sheep: Corriedale, Merino and Creole. Sheep from the three breeds (Merino n = 110, Corriedale n = 108 and Creole n = 10 were genotyped using the Illumina Ovine SNP50 beadchip®. Genetic diversity was evaluated by comparing the minor allele frequency (MAF among breeds. Population structure and genetic differentiation were assessed using STRUCTURE software, principal component analysis (PCA and fixation index (F ST. Fixed markers (MAF = 0 that were different among breeds were identified as specific breed markers. Using a subset of 18,181 single nucleotide polymorphisms (SNPs, PCA and STUCTURE analysis were able to explain population stratification within breeds. Merino and Corriedale divergent lines showed high levels of polymorphism (89.4% and 86% of polymorphic SNPs, respectively and moderate genetic differentiation (F ST = 0.08 between them. In contrast, Creole had only 69% polymorphic SNPs and showed greater genetic differentiation from the other two breeds (F ST = 0.17 for both breeds. Hence, a subset of molecular markers present in the OvineSNP50 is informative enough for breed assignment and population structure analysis of commercial and Creole breeds.

  18. Growth, structure, Hirshfeld surface and spectroscopic properties of 2-amino-4-hydroxy-6-methylpyrimidinium-2,3-pyrazinedicorboxylate single crystal

    Science.gov (United States)

    Faizan, Mohd; Alam, Mohammad Jane; Afroz, Ziya; Rodrigues, Vítor Hugo Nunes; Ahmad, Shabbir

    2018-03-01

    The present work is focused on the crystal structure, vibrational spectroscopy and DFT calculations of hydrogen bonded 2,3-pyrazinedicorboxylic acid and 2-amino-4-hydroxy-6-methylpyrimidine (PDCA-.AHMP+) crystal. The crystal structure has been determined using single crystal X-ray diffraction analysis which shows that the crystal belongs to monoclinic space group P21/n. The PDCA-.AHMP+ crystal has been characterized by FTIR, FT-Raman and FT-NMR spectroscopic techniques. The FTIR and FT-Raman spectra of the complex have unique spectroscopic feature as compared with those of the starting material to confirm salt formation. The theoretical vibrational studies have been performed to understand the modes of the vibrations of asymmetric unit of the complex by DFT methods. Hirschfeld surface and 2D fingerprint plots analyses were carried out to investigate the intermolecular interactions and its contribution in the building of PDCA-.AHMP+ crystal. The experimental and simulated 13C and 1H NMR studies have assisted in structural analysis of PDCA-.AHMP+ crystal. The electronic spectroscopic properties of the complex were explored by the experimental as well as theoretical electronic spectra simulated using TD-DFT/IEF-PCM method at B3LYP/6-311++G (d,p) level of theory. In addition, frontier molecular orbitals, molecular electrostatic potential map (MEP) and nonlinear optical (NLO) properties using DFT method have been also presented.

  19. Study on the Reactivity of Amino Acid Chemosensor, NPFNP, with Ethanol: Structural Elucidation through Single Crystal XRD and DFT Calculations

    Directory of Open Access Journals (Sweden)

    Beena Varghese

    2017-01-01

    Full Text Available A novel ethoxy derivative of an amino acid chemosensor, 3-naphthyl-1-phenyl-5-(2ʹ-fluoro-5ʹ-nitrophenyl-2-pyrazoline (NPFNP, has been synthesized and characterized by different spectroscopic methods.  A single crystal of the ethoxy derivative, 3-naphthyl-1-phenyl-5-(2ʹ-ethoxy-5ʹ-nitrophenyl-2-pyrazoline NPENP, has been obtained and characterized.  The structure holds interest as it carries biologically active pyrazoline as a central ring attaching to electron donating and withdrawing substituents. The major motivation for this work was to gain detailed insight into the structural parameters of this compound for investigating the influence of crystal packing and geometrical dimensions on optical properties. Time-dependent DFT calculations have been employed for comparing the XRD data with theoretical parameters. The results show that the DFT method at B3LYP/6-31G level can well reproduce the structure of the title compound.

  20. Flower-like hierarchical structures consisting of porous single-crystalline ZnO nanosheets and their gas sensing properties to volatile organic compounds (VOCs)

    International Nuclear Information System (INIS)

    Meng, Fanli; Hou, Nannan; Ge, Sheng; Sun, Bai; Jin, Zhen; Shen, Wei; Kong, Lingtao; Guo, Zheng; Sun, Yufeng; Wu, Hao; Wang, Chen; Li, Minqiang

    2015-01-01

    Highlights: • Flower-like hierarchical structures consisting of porous single-crystalline ZnO nanosheets were synthesized. • The flower-like hierarchical structured ZnO exhibited higher response and shorter response and recovery times. • The sensing mechanism of the flower-like hierarchical has been systematically analyzed. - Abstract: Flower-like hierarchical structures consisting of porous single-crystalline ZnO nanosheets (FHPSCZNs) were synthesized by a one-pot wet-chemical method followed by an annealing treatment, which combined the advantages between flower-like hierarchical structure and porous single-crystalline structure. XRD, SEM and HRTEM were used to characterize the synthesized FHPSCZN samples. The sensing properties of the FHPSCZN sensor were also investigated by comparing with ZnO powder sensor, which exhibited higher response and shorter response and recovery times. The sensing mechanism of the FHPSCZN sensor has been further analyzed from the aspects of electronic transport and gas diffusion

  1. Explicitly-Correlated Electronic-Structure Methods for Single-Reference and Multi-Reference Systems

    Science.gov (United States)

    Valeev, Edward

    2010-03-01

    but the resulting equations are immensely complex and are not suited for manual implementation. To derive, manipulate, and implement these equations we employed an automated compiler that can handle the more general algebraic structure of the CC-R12 equations, isolate the special R12 intermediates, factorize the resulting tensor expressions, and generate efficient computer codes. Evaluation of the nonstandard two-electron integrals is also carried out by a high-performance computer code produced by a specialized compiler. These developments have allowed us for the first time to investigate a range of unprecedented ground-state CC-R12 methods through CCSDTQ-R12. Application of these novel methods to small polyatomic molecules results in absolute electronic energies of chemical accuracy and without any extrapolation. A more practical approach to R12 coupled-cluster methods is to introduce explicit correlation by perturbation theory. My group has developed a family of CC-R12 methods that treat geminal terms alone (CCSD(2)R12), or in conjunction with triple excitations (CCSD(T)R12), in a manner similar the workings of the ``gold standard'' CCSD(T) method. The advantage of the perturbative route is that the standard CC equations are not modified, and technical changes to the MP2-R12 code are minor. We demonstrated that the CCSD(T)R12 method is a practical R12 variant of the CCSD(T) method with performance similar to the rigorous CCSD(T)-R12 counterpart. For the aforementioned HEAT example, the use of the CCSD(T)R12 method allows to reduce the basis set error to 2.8 kJ/mol in mean absolute sense and to 7.2 kJ/mol at most, all with the same triple-zeta basis set. Thus, the CCSD(T)R12 method with only a triple-zeta basis set seems to reach chemical accuracy on average. I will finally discuss how the R12 approach can be applied to any electronic state for which low-order reduced density matrices are available. This development allowed us to couple the R12 method with the multi

  2. Differential interaction kinetics of a bipolar structure-specific endonuclease with DNA flaps revealed by single-molecule imaging.

    Directory of Open Access Journals (Sweden)

    Rachid Rezgui

    Full Text Available As DNA repair enzymes are essential for preserving genome integrity, understanding their substrate interaction dynamics and the regulation of their catalytic mechanisms is crucial. Using single-molecule imaging, we investigated the association and dissociation kinetics of the bipolar endonuclease NucS from Pyrococcus abyssi (Pab on 5' and 3'-flap structures under various experimental conditions. We show that association of the PabNucS with ssDNA flaps is largely controlled by diffusion in the NucS-DNA energy landscape and does not require a free 5' or 3' extremity. On the other hand, NucS dissociation is independent of the flap length and thus independent of sliding on the single-stranded portion of the flapped DNA substrates. Our kinetic measurements have revealed previously unnoticed asymmetry in dissociation kinetics from these substrates that is markedly modulated by the replication clamp PCNA. We propose that the replication clamp PCNA enhances the cleavage specificity of NucS proteins by accelerating NucS loading at the ssDNA/dsDNA junctions and by minimizing the nuclease interaction time with its DNA substrate. Our data are also consistent with marked reorganization of ssDNA and nuclease domains occurring during NucS catalysis, and indicate that NucS binds its substrate directly at the ssDNA-dsDNA junction and then threads the ssDNA extremity into the catalytic site. The powerful techniques used here for probing the dynamics of DNA-enzyme binding at the single-molecule have provided new insight regarding substrate specificity of NucS nucleases.

  3. Insight into the three-dimensional structure of maize chlorotic mottle virus revealed by Cryo-EM single particle analysis.

    Science.gov (United States)

    Wang, Chun-Yan; Zhang, Qin-Fen; Gao, Yuan-Zhu; Zhou, Xue-Ping; Ji, Gang; Huang, Xiao-Jun; Hong, Jian; Zhang, Chuan-Xi

    2015-11-01

    Maize chlorotic mottle virus (MCMV) is the only member of the Machlomovirus genus in the family Tombusviridae. Here, we obtained the Cryo-EM structure of MCMV by single particle analysis with most local resolution at approximately 4 Å. The Cα backbone was built based on residues with bulky side chains. The resolved C-terminus of the capsid protein subunit and obvious openings at the 2-fold axis demonstrated the compactness of the asymmetric unit, which indicates an important role in the stability of MCMV. The Asp116 residue from each subunit around the 5-fold and 3-fold axes contributed to the negative charges in the centers of the pentamers and hexamers, which might serve as a solid barrier against the leakage of genomic RNA. Finally, the loops most exposed on the surface were analyzed and are proposed to be potential functional sites related to MCMV transmission. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Taking the ruler to the jungle: single-molecule FRET for understanding biomolecular structure and dynamics in live cells.

    Science.gov (United States)

    Sustarsic, Marko; Kapanidis, Achillefs N

    2015-10-01

    Single-molecule Förster resonance energy transfer (smFRET) serves as a molecular ruler that is ideally posed to study static and dynamic heterogeneity in living cells. Observing smFRET in cells requires appropriately integrated labeling, internalization and imaging strategies, and significant progress has been made towards that goal. Pioneering studies have demonstrated smFRET detection in both prokaryotic and eukaryotic systems, using both wide-field and confocal microscopies, and have started to answer exciting biological questions. We anticipate that future technical developments will open the door to smFRET for the study of structure, conformational changes and kinetics of biomolecules in living cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Structural and electrical properties of single crystalline SrZrO 3 epitaxially grown on Ge (001)

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Z. H.; Ahmadi-Majlan, K.; Grimley, E. D.; Du, Y.; Bowden, M.; Moghadam, R.; LeBeau, J. M.; Chambers, S. A.; Ngai, J. H.

    2017-08-28

    We present structural and electrical characterization of SrZrO3 that has been epitaxially grown on Ge(001) by oxide molecular beam epitaxy. Single crystalline SrZrO3 can be nucleated on Ge via deposition at low temperatures followed by annealing at 550 ºC in ultra-high vacuum. Photoemission spectroscopy measurements reveal that SrZrO3 exhibits a type-I band arrangement with respect to Ge, with conduction and valence band offsets of 1.4 eV and 3.65 eV, respectively. As a standalone film, SrZrO3 exhibits several characteristics that are ideal for applications as a gate dielectric on Ge. We find that 4 nm thick films exhibit low leakage current densities, and a dielectric constant of κ ~ 25 that corresponds to an equivalent oxide thickness of 0.70 nm.

  6. STRUCTURAL CALCULATIONS FOR THE LIFTING IN VERTICAL ORIENTATION OF 5-DHLW/DOE SNF SINGLE CRM WASTE PACKAGES

    International Nuclear Information System (INIS)

    S. Mastilovic

    1999-01-01

    The purpose of this activity is to determine the structural response of the extension of outer shell (which is referred to as skirt throughout this document) designs of both long and short design concepts of 5-Defense High-Level Waste (DHLW) Department of Energy (DOE) spent nuclear fuel (SNF) single corrosion resistant material (CRM) waste packages (WP), subjected to a gravitational load in the course of lifting in vertical orientation. The scope of this document is limited to reporting the calculation results in terms of stress intensity magnitudes. This activity is associated with the WP design; calculations are performed by the Waste Package Design group. AP-3.124, Revision 0, ICN 0, Calculations, is used to perform the calculation and develop the document

  7. WDM-Coherent OCDMA over one single device based on short chip Super Structured Fiber Bragg Gratings.

    Science.gov (United States)

    Amaya, Waldimar; Pastor, Daniel; Baños, Rocio; Garcia-Munoz, Victor

    2011-11-21

    We theoretically propose and demonstrate experimentally a Coherent Direct Sequence OCDMA en/decoder for multi-channel WDM operation based on a single device. It presents a broadband spectral envelope and a periodic spectral pattern that can be employed for en/decoding multiple sub-bands simultaneously. Multi-channel operation is verified experimentally by means of Multi-Band Super Structured Fiber Bragg Gratings with binary phase encoded chips fabricated with 1mm inter-chip separation that provides 4x100 GHz ITU sub-band separation at 1.25 Gbps. The WDM-OCDMA system verification was carried out employing simultaneous encoding of four adjacent sub-bands and two different OCDMA codes. © 2011 Optical Society of America

  8. Altering F-Actin Structure of C17.2 Cells using Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Magers, Jay; Gillette, Nathan L. D.; Rotkin, Slava V.; Jedlicka, Sabrina; Pirbhai, Massooma; Lehigh Univesity Collaboration; Susquehanna University Collaboration

    Advancements in nanotechnology have become fundamental to the delivery of drugs to treat various diseases. One such advancement is that of carbon nanotubes and their possible implications on drug delivery. Single-walled carbon nanotubes (SWCNTs) have great potential in the biomedical field as a means to deliver materials such as drugs and genes into the human body due to their size and chemistry. However, the effects of the nanotubes on cells they interact with are still unknown. Previous studies have shown that a low dosage of SWCNTs can affect differentiation of C17.2 neural stem cells. In this experiment, we investigate how the tubes affect the structure of the cells. Specifically, we determined the impact on the cell by examining the actin filament length, protrusions along the edge of the cells, and actin distribution. Presenter/Author 1.

  9. Optical and structural characterization of GaSb and Te-doped GaSb single crystals

    International Nuclear Information System (INIS)

    Tirado-Mejia, L.; Villada, J.A.; Rios, M. de los; Penafiel, J.A.; Fonthal, G.; Espinosa-Arbelaez, D.G.; Ariza-Calderon, H.; Rodriguez-Garcia, M.E.

    2008-01-01

    Optical and structural properties of GaSb and Te-doped GaSb single crystals are reported herein. Utilizing the photoreflectance technique, the band gap energy for doped samples was obtained at 0.814 eV. Photoluminescence (PL) spectra showed a peak at 0.748 eV that according to this research, belongs to electronic states of pure GaSb and not to the longitudinal optical (LO) phonon replica as has been reported by other authors. Analysis of the full width at half maximum (FWHM) values of X-ray diffraction, as well as micro-Raman peaks showed that the inclusion of Te decreases the crystalline quality

  10. N and Si Implantation Effect on Structural and Electrical Properties of Bridgman grown GaSe Single Crystal

    International Nuclear Information System (INIS)

    Karabulut, O.

    2004-01-01

    N and Si implantation to GaSe single crystals were carried out parallel to c-axis with ion beam of about 10 1 6 ions/cm 2 dose having energy values 30, 60 and 100 keV. Ion implantation modifications on Bridgman grown GaSe single crystals have been investigated by means of XRD, electrical conductivity, absorption and photoconductivity measurements. XRD measurements revealed that annealing results in a complete recovery of the crystalline nature that was moderately reduced upon implantation. It was observed that both N- and Siimplantation followed by annealing process decreased the resistivity values from 10 7 to 10 3 .-cm. The analysis of temperature dependent conductivity showed that at high temperature region above 200 K, the transport mechanism is dominated by thermal excitation in the doped and undoped GaSe samples. At lower temperatures, the conduction of carriers is dominated by variable range hopping mechanism in the implanted samples. Absorption and spectral photoconductivity measurements showed that the band edge is shifted in the implanted sample. All these modifications were attributed to the structural modifications and continuous shallow trap levels introduced upon implantation and annealing

  11. Integration of single oocyte trapping, in vitro fertilization and embryo culture in a microwell-structured microfluidic device.

    Science.gov (United States)

    Han, Chao; Zhang, Qiufang; Ma, Rui; Xie, Lan; Qiu, Tian; Wang, Lei; Mitchelson, Keith; Wang, Jundong; Huang, Guoliang; Qiao, Jie; Cheng, Jing

    2010-11-07

    In vitro fertilization (IVF) therapy is an important treatment for human infertility. However, the methods for clinical IVF have only changed slightly over decades: culture medium is held in oil-covered drops in Petri dishes and manipulation occurs by manual pipetting. Here we report a novel microwell-structured microfluidic device that integrates single oocyte trapping, fertilization and subsequent embryo culture. A microwell array was used to capture and hold individual oocytes during the flow-through process of oocyte and sperm loading, medium substitution and debris cleaning. Different microwell depths were compared by computational modeling and flow washing experiments for their effectiveness in oocyte trapping and debris removal. Fertilization was achieved in the microfluidic devices with similar fertilization rates to standard oil-covered drops in Petri dishes. Embryos could be cultured to blastocyst stages in our devices with developmental status individually monitored and tracked. The results suggest that the microfluidic device may bring several advantages to IVF practices by simplifying oocyte handling and manipulation, allowing rapid and convenient medium changing, and enabling automated tracking of any single embryo development.

  12. Growth, structural, optical, mechanical and quantum chemical analysis of unidirectional grown bis(guanidinium) 5-sulfosalicylate (BGSSA) single crystal

    Science.gov (United States)

    Sreedevi, R.; Saravana Kumar, G.; Amarsingh Bhabu, K.; Balu, T.; Murugakoothan, P.; Rajasekaran, T. R.

    2018-02-01

    Bis(guanidinium) 5-sulfosalicylate single crystal was grown by using Sankaranarayanan-Ramasamy (SR) method from the solution of methanol and water in equimolar ratio. Good quality crystal with 50 mm length and 10 mm in diameter was grown. The grown crystal was subjected to single crystal X-ray diffraction analysis to confirm the crystal structure and it was found to be orthorhombic. UV-Vis-NIR spectroscopic study revealed that the SR method grown crystal had good optical transparency with wide optical band gap of 4.4 eV. The presence of the functional groups and modes of vibrations were identified by FTIR spectroscopy recorded in the range 4000-400 cm-1. The mechanical strength of the grown crystal was confirmed using Vickers microhardness tester by applying load from 25 g to 100 g. Density functional theory (DFT) method with B3LYP/6-31-G (d,p) level basis set was employed and hence the optimized molecular geometry, first order hyperpolarizability, dipole moment, thermodynamic functions, molecular electrostatic potential and frontier molecular orbital analysis of the grown BGSSA sample was computed and analysed.

  13. Synthesis, growth, crystal structure, optical and third order nonlinear optical properties of quinolinium derivative single crystal: PNQI

    Science.gov (United States)

    Karthigha, S.; Krishnamoorthi, C.

    2018-03-01

    An organic quinolinium derivative nonlinear optical (NLO) crystal, 1-ethyl-2-[2-(4-nitro-phenyl)-vinyl]-quinolinium iodide (PNQI) was synthesized and successfully grown by slow evaporation solution growth technique. Formation of a crystalline compound was confirmed by single crystal X-ray diffraction. The quinolinium compound PNQI crystallizes in the triclinic crystal system with a centrosymmetric space group of P-1 symmetry. The molecular structure of PNQI was confirmed by 1H NMR and 13C NMR spectral studies. The thermal properties of the crystal have been investigated by thermogravimetric (TG) and differential scanning calorimetry (DSC) studies. The optical characteristics obtained from UV-Vis-NIR spectral data were described and the cut-off wavelength observed at 506 nm. The etching study was performed to analyse the growth features of PNQI single crystal. The third order NLO properties such as nonlinear refractive index (n2), nonlinear absorption coefficient (β) and nonlinear susceptibility (χ (3)) of the crystal were investigated using Z-scan technique at 632.8 nm of Hesbnd Ne laser.

  14. Computational Analysis of Damaging Single-Nucleotide Polymorphisms and Their Structural and Functional Impact on the Insulin Receptor

    Directory of Open Access Journals (Sweden)

    Zabed Mahmud

    2016-01-01

    Full Text Available Single-nucleotide polymorphisms (SNPs associated with complex disorders can create, destroy, or modify protein coding sites. Single amino acid substitutions in the insulin receptor (INSR are the most common forms of genetic variations that account for various diseases like Donohue syndrome or Leprechaunism, Rabson-Mendenhall syndrome, and type A insulin resistance. We analyzed the deleterious nonsynonymous SNPs (nsSNPs in INSR gene based on different computational methods. Analysis of INSR was initiated with PROVEAN followed by PolyPhen and I-Mutant servers to investigate the effects of 57 nsSNPs retrieved from database of SNP (dbSNP. A total of 18 mutations that were found to exert damaging effects on the INSR protein structure and function were chosen for further analysis. Among these mutations, our computational analysis suggested that 13 nsSNPs decreased protein stability and might have resulted in loss of function. Therefore, the probability of their involvement in disease predisposition increases. In the lack of adequate prior reports on the possible deleterious effects of nsSNPs, we have systematically analyzed and characterized the functional variants in coding region that can alter the expression and function of INSR gene. In silico characterization of nsSNPs affecting INSR gene function can aid in better understanding of genetic differences in disease susceptibility.

  15. Instrument for all-fiber structure measurement of ultra-low turbidity by using single photon detection technique

    Science.gov (United States)

    Qin, Feihu; Hu, Juntao; Wang, Huanqin; Gui, Huaqiao; Liu, Jianguo; Lü, Liang; Kong, Deyi; Zhang, Jian; Han, Xia; Wang, Tianli

    2017-10-01

    An all-fiber structure detection system based on single photon detection technique(SPDT) has been developed to measure the ultra-low turbidity ofliquids. To assure the measurement accuracy,the total intensity of transmission light has been detected and quantified as number of photons by avalanche photodiode (APD) which has the advantage of high sensitivity.A fresh all-fiber structure optical fiber probe based on SPDT is applied in the system to reduce the volume and fluctuation of traditional transmission-light measurement system,in which the all-fiber structure probe is used to delivery and collection of transmission light.On the basis of Beer-Lambert (B-L) transmission law,a test system has been established and carried out a series of experiments.By combining B-Llaw with the principle of SPDT,a novel model for detecting turbidity has been proposed to explain the experimental results.The results have shown a well exponential relationship over the range of 0.01-1NTU (Nephelometric Turbidity Units).It also has showna good linear relationship with a resolution as high as 0.01NTUin the range of 0.01-0.09 NTU.When it is 1 secondofthe sampling time,the mean error of measurement result can be controlled within 5% of full scale.In addition,the new detection structure proposed in this paper, which makes the system more compact and more suitable in the small special space.

  16. Genome-wide Single Nucleotide Polymorphism Analyses Reveal Genetic Diversity and Structure of Wild and Domestic Cattle in Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Rasel Uzzaman

    2014-10-01

    Full Text Available In spite of variation in coat color, size, and production traits among indigenous Bangladeshi cattle populations, genetic differences among most of the populations have not been investigated or exploited. In this study, we used a high-density bovine single nucleotide polymorphism (SNP 80K Bead Chip derived from Bos indicus breeds to assess genetic diversity and population structure of 2 Bangladeshi zebu cattle populations (red Chittagong, n = 28 and non-descript deshi, n = 28 and a semi-domesticated population (gayal, n = 17. Overall, 95% and 58% of the total SNPs (69,804 showed polymorphisms in the zebu and gayal populations, respectively. Similarly, the average minor allele frequency value was as high 0.29 in zebu and as low as 0.09 in gayal. The mean expected heterozygosity varied from 0.42±0.14 in zebu to 0.148±0.14 in gayal with significant heterozygosity deficiency of 0.06 (FIS in the latter. Coancestry estimations revealed that the two zebu populations are weakly differentiated, with over 99% of the total genetic variation retained within populations and less than 1% accounted for between populations. Conversely, strong genetic differentiation (FST = 0.33 was observed between zebu and gayal populations. Results of population structure and principal component analyses suggest that gayal is distinct from Bos indicus and that the two zebu populations were weakly structured. This study provides basic information about the genetic diversity and structure of Bangladeshi cattle and the semi-domesticated gayal population that can be used for future appraisal of breed utilization and management strategies.

  17. Parthenocarpic potential in Capsicum annuum L. is enhanced by carpelloid structures and controlled by a single recessive gene

    Directory of Open Access Journals (Sweden)

    Xue Lin B

    2011-10-01

    Full Text Available Abstract Background Parthenocarpy is a desirable trait in Capsicum annuum production because it improves fruit quality and results in a more regular fruit set. Previously, we identified several C. annuum genotypes that already show a certain level of parthenocarpy, and the seedless fruits obtained from these genotypes often contain carpel-like structures. In the Arabidopsis bel1 mutant ovule integuments are transformed into carpels, and we therefore carefully studied ovule development in C. annuum and correlated aberrant ovule development and carpelloid transformation with parthenocarpic fruit set. Results We identified several additional C. annuum genotypes with a certain level of parthenocarpy, and confirmed a positive correlation between parthenocarpic potential and the development of carpelloid structures. Investigations into the source of these carpel-like structures showed that while the majority of the ovules in C. annuum gynoecia are unitegmic and anatropous, several abnormal ovules were observed, abundant at the top and base of the placenta, with altered integument growth. Abnormal ovule primordia arose from the placenta and most likely transformed into carpelloid structures in analogy to the Arabidopsis bel1 mutant. When pollination was present fruit weight was positively correlated with seed number, but in the absence of seeds, fruit weight proportionally increased with the carpelloid mass and number. Capsicum genotypes with high parthenocarpic potential always showed stronger carpelloid development. The parthenocarpic potential appeared to be controlled by a single recessive gene, but no variation in coding sequence was observed in a candidate gene CaARF8. Conclusions Our results suggest that in the absence of fertilization most C. annuum genotypes, have parthenocarpic potential and carpelloid growth, which can substitute developing seeds in promoting fruit development.

  18. A national assessment of underground natural gas storage: identifying wells with designs likely vulnerable to a single-point-of-failure

    Science.gov (United States)

    Michanowicz, Drew R.; Buonocore, Jonathan J.; Rowland, Sebastian T.; Konschnik, Katherine E.; Goho, Shaun A.; Bernstein, Aaron S.

    2017-05-01

    The leak of processed natural gas (PNG) from October 2015 to February 2016 from the Aliso Canyon storage facility, near Los Angeles, California, was the largest single accidental release of greenhouse gases in US history. The Interagency Task Force on Natural Gas Storage Safety and California regulators recently recommended operators phase out single-point-of-failure (SPF) well designs. Here, we develop a national dataset of UGS well activity in the continental US to assess regulatory data availability and uncertainty, and to assess the prevalence of certain well design deficiencies including single-point-of-failure designs. We identified 14 138 active UGS wells associated with 317 active UGS facilities in 29 states using regulatory and company data. State-level wellbore datasets contained numerous reporting inconsistencies that limited data concatenation. We identified 2715 active UGS wells across 160 facilities that, like the failed well at Aliso Canyon, predated the storage facility, and therefore were not originally designed for gas storage. The majority (88%) of these repurposed wells are located in OH, MI, PA, NY, and WV. Repurposed wells have a median age of 74 years, and the 2694 repurposed wells constructed prior to 1979 are particularly likely to exhibit design-related deficiencies. An estimated 210 active repurposed wells were constructed before 1917—before cement zonal isolation methods were utilized. These wells are located in OH, PA, NY, and WV and represent the highest priority related to potential design deficiencies that could lead to containment loss. This national baseline assessment identifies regulatory data uncertainties, highlights a potentially widespread vulnerability of the natural gas supply chain, and can aid in prioritization and oversight for high-risk wells and facilities.

  19. Effects of single nucleotide polymorphisms on human N-acetyltransferase 2 structure and dynamics by molecular dynamics simulation.

    Directory of Open Access Journals (Sweden)

    M Rajasekaran

    Full Text Available BACKGROUND: Arylamine N-acetyltransferase 2 (NAT2 is an important catalytic enzyme that metabolizes the carcinogenic arylamines, hydrazine drugs and chemicals. This enzyme is highly polymorphic in different human populations. Several polymorphisms of NAT2, including the single amino acid substitutions R64Q, I114T, D122N, L137F, Q145P, R197Q, and G286E, are classified as slow acetylators, whereas the wild-type NAT2 is classified as a fast acetylator. The slow acetylators are often associated with drug toxicity and efficacy as well as cancer susceptibility. The biological functions of these 7 mutations have previously been characterized, but the structural basis behind the reduced catalytic activity and reduced protein level is not clear. METHODOLOGY/PRINCIPAL FINDINGS: We performed multiple molecular dynamics simulations of these mutants as well as NAT2 to investigate the structural and dynamical effects throughout the protein structure, specifically the catalytic triad, cofactor binding site, and the substrate binding pocket. None of these mutations induced unfolding; instead, their effects were confined to the inter-domain, domain 3 and 17-residue insert region, where the flexibility was significantly reduced relative to the wild-type. Structural effects of these mutations propagate through space and cause a change in catalytic triad conformation, cofactor binding site, substrate binding pocket size/shape and electrostatic potential. CONCLUSIONS/SIGNIFICANCE: Our results showed that the dynamical properties of all the mutant structures, especially in inter-domain, domain 3 and 17-residue insert region were affected in the same manner. Similarly, the electrostatic potential of all the mutants were altered and also the functionally important regions such as catalytic triad, cofactor binding site, and substrate binding pocket adopted different orientation and/or conformation relative to the wild-type that may affect the functions of the mutants

  20. Controlling the formation process and atomic structures of single pyrazine molecular junction by tuning the strength of the metal-molecule interaction.

    Science.gov (United States)

    Kaneko, Satoshi; Takahashi, Ryoji; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

    2017-04-12

    The formation process and atomic structures were investigated for single pyrazine molecular junctions sandwiched by three different Au, Ag, and Cu electrodes using a mechanically controllable break junction technique in ultrahigh vacuum conditions at 300 K. We demonstrated that the formation process of the single-molecule junction crucially depended on the choice of the metal electrodes. While single-molecule junction showing two distinct conductance states were found for the Au electrodes, only the single conductance state was evident for the Ag electrodes, and there was no junction formation for the Cu electrodes. These results suggested that metal-molecule interaction dominates the formation process and probability of the single-molecule junction. In addition to the metal-molecule interaction, temperature affected the formation process of the single-molecule junction. The single pyrazine molecular junction formed between Au electrodes exhibited significant temperature dependence where the junction-formation probability was about 8% at 300 K, while there was no junction-formation at 100 K. Instead of the junction formation, an Au atomic wire was formed at the low temperature. This study provides insight into the tuning of the junction-forming process for single-molecule junctions, which is needed to construct device structures on a single molecule scale.

  1. Effect of foundation flexibility on the vibrational stability of the National Ignition Facility optical system support structures

    International Nuclear Information System (INIS)

    McCallen, D.

    1997-01-01

    Alignment requirements for the National Ignition Facility (NIF) optical components will require a number of support structures which minimize the system displacements and deformations. The stringent design requirements for this facility will result in a system in which vibrations due to ambient environmental loads (e.g. foundation motion due to typical traffic loads, microseisms or nearby equipment) will have a significant, and perhaps predominant, influence on the design of the supporting structures. When considering the total deformations and displacements of the structural systems, the contribution of the foundation to the overall system flexibility must be addressed. Classical fixed-base structural analyses, which are predicated on an assumption of an infinitely rigid foundation system, neglect the influence of foundation flexibility and for the vibration regime in which the NIF structures reside, may result in significant underestimation of the system ambient vibration displacements. In the work described herein, parametric studies were performed in order to understand the potential contributions of soil-structure- interaction (SSI) to optical system displacements. Time domain finite element analyses were employed to quantify the effect of wave scattering by the mat foundation and the effects of inertial SSI due to the rocking of the massive shear wall support structures. A simplified procedure is recommended for accounting for SSI effects in the design of the special equipment structures. The simplified approach consists of applying a scale factor to displacements obtained from fixed base analyses to approximately account for the effects of soil-structure interaction and variable support input motion

  2. Single layers and multilayers of GaN and AlN in square-octagon structure: Stability, electronic properties, and functionalization

    Science.gov (United States)

    Gürbüz, E.; Cahangirov, S.; Durgun, E.; Ciraci, S.

    2017-11-01

    Further to planar single-layer hexagonal structures, GaN and AlN can also form free-standing, single-layer structures constructed from squares and octagons. We performed an extensive analysis of dynamical and thermal stability of these structures in terms of ab initio finite-temperature molecular dynamics and phonon calculations together with the analysis of Raman and infrared active modes. These single-layer square-octagon structures of GaN and AlN display directional mechanical properties and have wide, indirect fundamental band gaps, which are smaller than their hexagonal counterparts. These density functional theory band gaps, however, increase and become wider upon correction. Under uniaxial and biaxial tensile strain, the fundamental band gaps decrease and can be closed. The electronic and magnetic properties of these single-layer structures can be modified by adsorption of various adatoms, or by creating neutral cation-anion vacancies. The single-layer structures attain magnetic moment by selected adatoms and neutral vacancies. In particular, localized gap states are strongly dependent on the type of vacancy. The energetics, binding, and resulting electronic structure of bilayer, trilayer, and three-dimensional (3D) layered structures constructed by stacking the single layers are affected by vertical chemical bonds between adjacent layers. In addition to van der Waals interaction, these weak vertical bonds induce buckling in planar geometry and enhance their binding, leading to the formation of stable 3D layered structures. In this respect, these multilayers are intermediate between van der Waals solids and wurtzite crystals, offering a wide range of tunability.

  3. Structure of attitudes toward illegal immigration: development of cross-national cumulative scales.

    Science.gov (United States)

    van der Veer, Kees; Ommundsen, Reidar; Larsen, Knud S; Le, Hao Van; Krumov, Krum; Pernice, Regina E; Romans, Gerardo Pastor

    2004-06-01

    This research examined the possibility of developing Mokken cumulative scales measuring attitudes toward illegal immigrants in a 9-nation sample. A total of 1,407 respondents primarily from national and regional universities participated in the surveys including the 20-item Illegal Immigration Scale. The scales displayed acceptable reliability with coefficients alpha ranging from .79 to .93. A Procrustes analysis yielded coefficients of congruence with the previously established three-factor solution. The amount of variance accounted for varied between 33.1 and 54.7%, supporting the presence of other factors in attitudes toward illegal immigrants. Mokken scale analysis yielded robust and economical scales in two clusters of national samples.

  4. Impact of Structural Adjustment Programmes on National Food Security in Kenya

    International Nuclear Information System (INIS)

    Oduol, A.B.

    2002-01-01

    Per capita food production in sub-Saharan Africa including Kenya has been declining over the past three decades.Despite the available efforts made by the governments in sub-Saharan Africa, food insecurity remains one of the most crucial issues.In Kenya, agriculture accounts for about 26 per cent of overall GDP, 60 per cent of foreign exchange earnings and employs about 70 per cent of the rural population. Agriculture therefore remains the main source of food security for a majority of Kenya's population. Kenya has been going through nearly a decade of transition in agriculture whereby the role of the state in production and marketing has been reduced allowing the public sector institutions to concentrate on doing a narrow range of tasks better. However concerns has arisen as to wether this transformation from state-led model of service provision to that of the private sector would result in the vibrant growth in agricultural production that was experienced in the 1960s and early 1970s. This study sought to determine the impact of policy reforms on national food security with a major focus on agricultural production of rural farmers in Kenya. The study also aimed at suggesting posssible recommendations to improve agricultural production while taking into consideration the fiscal constraint faced by the the country. By using descriptive analysis to compare changes in production of maize, coffee and tea as well as in the food security situation before and after policy reforms, the study revealed that maize production had declined in the post-reform period. Although the total contribution of tea and coffee to total agricultural export had increased in the pos-reform period, production of coffee showed a downward trend unlike that of tea. The results further revealed that food production had deteriorated in the post-reform period while dependence on food imports and food aid had increased. In conclusion, the structural adjustment programmes coupled with organisational

  5. 78 FR 70540 - Meeting of the National Commission on the Structure of the Air Force

    Science.gov (United States)

    2013-11-26

    ... structure. --The root causes of legislative and bureaucratic development of the force structure issues that... section 10(a)(3) of the FACA, the public or interested organizations may submit written comments to the...

  6. Special structures and properties of hydrogen nanowire confined in a single walled carbon nanotube at extreme high pressure

    Directory of Open Access Journals (Sweden)

    Yueyuan Xia

    2012-06-01

    Full Text Available Extensive ab initio molecular dynamics simulations indicate that hydrogen can be confined in single walled carbon nanotubes to form high density and high pressure H2 molecular lattice, which has peculiar shell and axial structures depending on the density or pressure. The band gap of the confined H2 lattice is sensitive to the pressure. Heating the system at 2000K, the H2 lattice is firstly melted to form H2 molecular liquid, and then some of the H2 molecules dissociate accompanied by drastic molecular and atomic reactions, which have essential effect on the electronic structure of the hydrogen system. The liquid hydrogen system at 2000K is found to be a particular mixed liquid, which consists of H2 molecules, H atoms, and H-H-H trimers. The dissociated H atoms and the trimers in the liquid contribute resonance electron states at the Fermi energy to change the material properties substantially. Rapidly cooling the system from 2000K to 0.01 K, the mixed liquid is frozen to form a mixed solid melt with a clear trend of band gap closure. It indicates that this solid melt may become a superconducting nanowire when it is further compressed.

  7. Structural, mechanical and light yield characterisation of heat treated LYSO:Ce single crystals for medical imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Mengucci, P., E-mail: p.mengucci@univpm.it [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); André, G. [Laboratoire Léon Brillouin, CEA-CNRS, CE-Saclay, 91191 Gif sur Yvette cedex (France); Auffray, E. [Department PH-CMX CERN, Route de Meyrin, 1211 Geneva 23 (Switzerland); Barucca, G. [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); Cecchi, C. [Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, 06123 Perugia (Italy); Chipaux, R. [CEA DSM/IRFU/SEDI, CE-Saclay, 91191 Gif sur Yvette cedex (France); Cousson, A. [Laboratoire Léon Brillouin, CEA-CNRS, CE-Saclay, 91191 Gif sur Yvette cedex (France); Davì, F. [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy); Di Vara, N. [Department PH-CMX CERN, Route de Meyrin, 1211 Geneva 23 (Switzerland); Rinaldi, D.; Santecchia, E. [Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy)

    2015-06-11

    Five single crystals of cerium-doped lutetium yttrium oxyorthosilicate (LYSO:Ce) grown by the Czochralski method were submitted to structural characterisation by X-ray (XRD) and neutron (ND) diffraction, scanning (SEM) and transmission (TEM) electron microscopy and energy dispersive microanalysis (EDS). The Ultimate Tensile Strength (UTS), the Young Modulus (YM) and the Light Yield (LY) of the samples were also measured in order to correlate the mechanical and the optical behaviour of the crystals with the characteristics of their microstructure. Two of the samples analysed were also heat treated at 300 °C for 10 h to evidence possible variations induced by the temperature in the optical and mechanical response of the crystals. Results showed that the mean compositional variations evidenced by the structural analyses do not affect the mechanical and optical behaviour of the samples. On the contrary, the thermal treatment could induce the formation of coherent spherical particles (size 10 to 15 nm), not uniformly distributed inside the sample, that strongly reduce the UTS and YM values, but it does not affect the optical response of the crystal. This latter result was attributed to the low value of the heating temperature (300 °C) that is not sufficiently high to induce annealing of the oxygen vacancies traps that are responsible of the deterioration of the scintillation properties of the LYSO:Ce crystals. This study was carried out in the framework of the Crystal Clear Collaboration (CCC)

  8. Sexithiophene encapsulated in a single-walled carbon nanotube: an in situ Raman spectroelectrochemical study of a peapod structure.

    Science.gov (United States)

    Kalbáč, Martin; Kavan, Ladislav; Gorantla, Sandeep; Gemming, Thomas; Dunsch, Lothar

    2010-10-11

    The interaction of single-walled carbon nanotubes (SWCNTs) and α-sexithiophene (6T) was studied by Raman spectroscopy and by in situ Raman spectroelectrochemistry. The encapsulation of 6T in SWCNT and its interaction causes a bleaching of its photoluminescence, and also small shifts of its Raman bands. The Raman features of the SWCNT with embedded 6T (6T-peapods) change in both intensity and frequency compared to those of pristine SWCNT, which is a consequence of a change of the resonant condition. Electrochemical doping demonstrated that the electrode potential applied to the SWCNT wall causes changes in the embedded 6T. The effects of electrochemical charging on the Raman features of pristine SWCNT and 6T@SWCNT were compared. It is shown that the interaction of SWCNT with 6T also changes the electronic structure of SWCNT in its charged state. This change of electronic structure is demonstrated both for semiconducting and metallic tubes. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    Poola, Praveen Kumar; John, Renu

    2017-10-01

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

  10. Pressure-induced topological phase transitions and structural transition in 1T-TiTe2 single crystal

    Science.gov (United States)

    Zhang, Min; Wang, Xiangqi; Rahman, Azizur; Zeng, Qunsong; Huang, Da; Dai, Rucheng; Wang, Zhongping; Zhang, Zengming

    2018-01-01

    High pressure in situ Raman scattering and electrical resistivity measurements were performed to investigate the phase transitions in a semimetal 1T-TiTe2 single crystal up to 17 GPa. Combining anomalous experimental results with the electronic band structures and Z2 topological invariants in calculations, two topological phase transitions and one structural phase transition were confirmed at 1.7 GPa, 3 GPa, and 8 GPa, respectively. These two topological transformations are due to the enhanced orbital hybridization followed by a few of band inversions near the Fermi level, and the further parity analysis manifested that the phases II and III correspond to a strong topological state and a weak topological state, respectively. The rich topology variation of 1T-TiTe2 under high pressure provides a potential candidate for understanding the relevant topology physics and probable applications. The current results also demonstrate that Raman spectroscopy and electrical transport measurements are efficient tools to detect the topological phase transition under high pressure.

  11. Periodic density functional theory study of structural and electronic properties of single-walled zinc oxide and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Marana, Naiara L. [Modeling and Molecular Simulations Group, São Paulo State University, UNESP, 17033-360 Bauru, SP (Brazil); Albuquerque, Anderson R. [Federal Institute of Education, Science and Technology of Sertão Pernambucano, 56400-000 Floresta, PE (Brazil); La Porta, Felipe A. [Chemistry Department, Federal Technological University of Paraná, 86036-370 Londrina, PR (Brazil); Longo, Elson [São Paulo State University, Chemistry Institute, UNESP, 14801-907 Araraquara, SP (Brazil); Sambrano, Julio R. [Modeling and Molecular Simulations Group, São Paulo State University, UNESP, 17033-360 Bauru, SP (Brazil)

    2016-05-15

    Periodic density functional theory calculations with the B3LYP hybrid functional and all-electron Gaussian basis set were performed to simulate the structural and electronic properties as well as the strain and formation energies of single-walled ZnO nanotubes (SWZnONTs) and Carbon nanotubes (SWCNTs) with different chiralities as functions of their diameters. For all SWZnONTs, the band gap, strain energy, and formation energy converge to ~4.5 eV, 0.0 eV/atom, and 0.40 eV/atom, respectively. This result suggests that the nanotubes are formed more easily from the surface than from the bulk. For SWCNTs, the strain energy is always positive, while the formation energy is negative for armchair and zigzag nanotubes, therefore suggesting that these types of nanotubes can be preferentially formed from the bulk. The electronic properties of SWCNTs depend on the chirality; all armchair nanotubes are metallic, while zigzag and chiral nanotubes can be metallic or semiconducting, depending on the n and m vectors. - Graphical abstract: DFT/B3LYP were performed to simulate the structural and electronic properties as well as the strain and formation energies of SWZnONTs and SWCNTs with different chiralities as functions of their diameters. - Highlights: • The energies of SWZnONTs converge for chirality with diameters up 20 Å. • SWCNTs electronic properties depend on the chirality. • The properties of SWZnONTs are very similar to those of monolayer surface.

  12. Relevance of Army National Guard Infantry Units in the Force Structure and Their Role in Combat

    National Research Council Canada - National Science Library

    Harris, Brian

    2004-01-01

    ...% of a total force of 346,848 assigned. Such large numbers are staggering considering that National Guard infantry units are not being utilized according to their organization training and equipment...

  13. LBA-ECO CD-02 Forest Canopy Structure, Tapajos National Forest, Brazil: 1999-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports on Leaf Area Index (LAI) and Specific Leaf Area (SLA) measurements collected from forest and pasture sites in or near the Tapajos...

  14. 75 FR 38831 - Repair Kalaupapa Dock Structure: Kalaupapa National Historical Park, Hawaii; Notice of...

    Science.gov (United States)

    2010-07-06

    ..., species protected under the Endangered Species Act and the Marine Mammal Protection Act, historic... well as further coordination with USFWS and National Marine Fisheries Service, the scope of work...

  15. Growth, structure and optical properties of Tl{sub 4}HgBr{sub 6} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Khyzhun, O.Y., E-mail: khyzhun@ipms.kiev.ua [Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3 Krzhyzhanivsky Street, 03142 Kyiv (Ukraine); Kityk, I.V. [Electrical Engineering Department, Częstochowa University of Technology, Armii Krajowej 17, PL-42-217 Częstochowa (Poland); Piasecki, M. [Institute of Physics, J. Dlugosz University Częstochowa, Armii Krajowej 13/15, Częstochowa (Poland); Fedorchuk, A.O. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, 50 Pekarska Street, 79010 Lviv (Ukraine); Levkovets, S.I. [Department of Inorganic and Physical Chemistry, Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine); Fochuk, P.M. [Yuriy Fed’kovych Chernivtsi National University, 2 Kotziubynskoho Street, 58012 Chernivtsi (Ukraine); Myronchuk, G.L. [Department of Solid State Physics, Lesya Ukrainka Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine); Parasyuk, O.V. [Department of Inorganic and Physical Chemistry, Eastern European National University, 13 Voli Avenue, 43025 Lutsk (Ukraine)

    2015-12-15

    Tl{sub 4}HgBr{sub 6} single crystals were grown using solution-fusion method. The crystal structure of the ternary bromide was refined. Tl{sub 4}HgBr{sub 6} crystallizes in the non-centrosymmetric space group P4nc with the lattice parameters a=8.9539(8) Å and c=8.7884(8) Å and it is isostructural to the Tl{sub 4}HgI{sub 6} compound. The non-centrosymmetric structure of the Tl{sub 4}HgBr{sub 6} compound was also confirmed by the existence of a modest second harmonic generation effect (0.4–0.5 pm/V) and by the value of piezoelectric coefficient (0.9 pm/V). The electronic structure of Tl{sub 4}HgBr{sub 6} was explored using X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES). In particular, for the Tl{sub 4}HgBr{sub 6} crystal, we have measured XPS core-level and valence-band spectra for both pristine and Ar{sup +} ion-bombarded surfaces. The XPS data reveal low hygroscopicity of Tl{sub 4}HgBr{sub 6}, the property that is very important when handling this material in optoelectronic devices working at ambient conditions. The present XPS data indicate that the Tl{sub 4}HgBr{sub 6} single crystal surface is rather sensitive with respect to Ar{sup +} ion-bombardment: such a treatment reduces significantly mercury content in the topmost surface layers. Comparison on a common energy scale of the XPS valence-band spectrum of Tl{sub 4}HgBr{sub 6} and the XE Br Kβ{sub 2} band, representing peculiarities of the energy distribution of the Br 4 p states, reveals that the main contribution of the valence Br p states occurs in the upper portion of the valence band, with also their significant contributions in other valence band regions. The measurements of spectral distribution of the absorption coefficient indicate that the Tl{sub 4}HgBr{sub 6} compound is a semiconductor with the bandgap energy value of 2.43 eV at 300 K, and the bandgap energy increases up to 2.48 eV when temperature decreases to 100 K.

  16. Sulfur single-wavelength anomalous diffraction crystal structure of a pheromone-binding protein from the honeybee Apis mellifera L.

    Science.gov (United States)

    Lartigue, Audrey; Gruez, Arnaud; Briand, Loïc; Blon, Florence; Bézirard, Valérie; Walsh, Martin; Pernollet, Jean-Claude; Tegoni, Mariella; Cambillau, Christian

    2004-02-06

    Pheromone binding proteins (PBPs) are small helical proteins ( approximately 13-17 kDa) present in several sensory organs from moth and other insect species. They are involved in the transport of pheromones from the sensillar lymph to the olfactory receptors. We report here the crystal structure of a PBP (Amel-ASP1) originating from the honey-bee (Apis mellifera) antennae and expressed as recombinant protein in the yeast Pichia pastoris. Crystals of Amel-ASP1 were obtained at pH 5.5 using the nano-drops technique of crystallization with a novel optimization procedure, and the structure was solved initially with the single-wavelength anomalous diffraction technique using sulfur anomalous dispersion. The structure of Amel-ASP1 has been refined at 1.6-A resolution. Its fold is roughly similar to that of other PBP/odorant binding proteins, presenting six helices and three disulfide bridges. Contrary to the PBPs from Bombyx mori (Sandler, B. H., Nikonova, L., Leal, W. S., and Clardy, J. (2000) Chem. Biol. 7, 143-151) and Leucophea maderae (Lartigue, A., Gruez, A., Spinelli, S., Riviere, S., Brossut, R., Tegoni, M., and Cambillau, C. (2003) J. Biol. Chem. 278, 30213-30218), the extended C terminus folds into the protein and forms a wall of the internal hydrophobic cavity. Its backbone groups establish two hydrogen bonds with a serendipitous ligand, n-butyl-benzene-sulfonamide, an additive used in plastics. This mode of binding might, however, mimic that used by one of the pheromonal blend components and illustrates the binding versatility of PBPs.

  17. Structuring oil and gas joint venture agreements on First Nations lands (south of the 60. parallel)

    International Nuclear Information System (INIS)

    Rae, LD.

    1998-01-01

    The advantages that arise from the unique legal regimes that apply to oil and gas exploration and production on First Nations lands were discussed. A significant portion of Canada's Aboriginal communities are located close to areas that will experience intense oil and gas exploration activities in the coming years. In southern Canada, there are 57 First Nations that have oil and gas exploration and/or production on their lands. A total of 179 oil and gas companies have interests on these lands. By law, First Nations do not have the right to develop and exploit the oil and gas resources on their reserve lands if this requires disposition of any portion of these lands to third parties. As a result, they must rely on the Crown's trust and fiduciary obligations to them to administer these resources. As the law now stands, Indian Oil and Gas Canada (IOGC) is obligated to consult with the First Nation community, but it is not obligated to necessarily act in accordance with the community's wishes. As can be expected, under these circumstances the opportunities for stalemates are significant. The difficulties experienced by industry on dealing with the IOGC are described, and alternatives to the current situation are proposed. Suggestions are also offered as to how title uncertainties may be overcome and how First Nations may achieve healthy economic growth right now, even prior to achieving self-government

  18. Intramolecular structures in a single copolymer chain consisting of flexible and semiflexible blocks: Monte Carlo simulation of a lattice model

    International Nuclear Information System (INIS)

    Martemyanova, Julia A; Ivanov, Victor A; Paul, Wolfgang

    2014-01-01

    We study conformational properties of a single multiblock copolymer chain consisting of flexible and semiflexible blocks. Monomer units of different blocks are equivalent in the sense of the volume interaction potential, but the intramolecular bending potential between successive bonds along the chain is different. We consider a single flexible-semiflexible regular multiblock copolymer chain with equal content of flexible and semiflexible units and vary the length of the blocks and the stiffness parameter. We perform flat histogram type Monte Carlo simulations based on the Wang-Landau approach and employ the bond fluctuation lattice model. We present here our data on different non-trivial globular morphologies which we have obtained in our model for different values of the block length and the stiffness parameter. We demonstrate that the collapse can occur in one or in two stages depending on the values of both these parameters and discuss the role of the inhomogeneity of intraglobular distributions of monomer units of both flexible and semiflexible blocks. For short block length and/or large stiffness the collapse occurs in two stages, because it goes through intermediate (meta-)stable structures, like a dumbbell shaped conformation. In such conformations the semiflexible blocks form a cylinder-like core, and the flexible blocks form two domains at both ends of such a cylinder. For long block length and/or small stiffness the collapse occurs in one stage, and in typical conformations the flexible blocks form a spherical core of a globule while the semiflexible blocks are located on the surface and wrap around this core.

  19. Structural and magnetic ordering of CrNb3S6 single crystals grown by gas transport method

    Science.gov (United States)

    Borisenko, E. B.; Berezin, V. A.; Kolesnikov, N. N.; Gartman, V. K.; Matveev, D. V.; Shakhlevich, O. F.

    2017-07-01

    Paramagnetic layered semiconductor NbS2 doped with some transition metals can transform into ferromagnetic material. That is why such materials are promising candidates for spintronic devices. It is found that only at certain concentrations of a doping metal T crystallographic ordering is possible, which is essential for magnetic ordering of ternary compounds TNbS2. In particular, CrNb3S6 crystals are studied, which form almost completely ordered superstructure with intercalated Cr between NbS2 layers. The main difficulty in crystal growth is reaching stoichiometry of the compound. This problem is solved in the developed method of two-staged gas transport chemical reaction. This new approach provides growth of CrNb3S6 single crystals of several millimeters in diameter and 0.3-0.5 mm thickness. X-ray phase analysis (XRD) of powders is performed to identify all phases involved in synthesis and growth of the crystals. High frequency absorption in external periodic magnetic field as a function of temperature and intensity of magnetic field is used to estimate the temperature of ferromagnetic transition in CrNb3S6 single crystals. The Curie temperature is estimated as 115 K. Growth of CrNb3S6 crystals from vapor phase is studied in detail and full analysis of phase transitions during growth is given. It has been shown that using of high frequency absorption in the crystal provides reliable estimation of the point of ferromagnetic transition in this semiconductor. The authors are grateful to the Physical Science Department of Russian Academy of Sciences for financial support of the studies in the frameworks of the program "Physics of new materials and structures" (project no. 00-12-10).

  20. Raman scattering study of the structural phase transition in single crystal KDy(MoO4)2

    Science.gov (United States)

    Peschanskii, A. V.

    2017-11-01

    Raman scattering of light in single-crystal KDy(MoO4)2 is studied at frequencies of 3-1000 cm-1 for temperatures ranging from 2 to 300 K, including that of a structural phase transition of the cooperative Jahn-Teller type (TC ˜ 14.5 K). During the transition to the low-temperature phase, a series of additional phonon lines corresponding to the Ag, B1g, B2g, and B3g modes is observed which indicates a doubling of the unit cell during the phase transition. An analysis of the symmetry of the phonon modes shows that the low-temperature phase has a predominantly monoclinic symmetry with conservation of a second order axis along the crystallographic b direction, i.e., perpendicular to the layers. Excitations are discovered which correspond to low-energy electronic transitions between levels of the ground-state 6H15/2 multiplet of the Dy3+ ion, which is split in the crystal field with a C2 symmetry. In the vicinity of the first excited Kramers doublet of the Dy3+ ion in crystalline KDy(MoO4)2, the scattered spectrum contains four lines [16.5, 21.0, 24.9, and 29.1 cm-1 (2 K)] at low temperatures, instead of a single line [18.3 cm-1 (25 K)] above the phase transition temperature (14.5 K). This indicates the existence of four nonequivalent dysprosium ions in the low-temperature phase.