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Sample records for wln t66 bn

  1. Draft genome sequence of the docosahexaenoic acid producing thraustochytrid Aurantiochytrium sp. T66.

    Science.gov (United States)

    Liu, Bin; Ertesvåg, Helga; Aasen, Inga Marie; Vadstein, Olav; Brautaset, Trygve; Heggeset, Tonje Marita Bjerkan

    2016-06-01

    Thraustochytrids are unicellular, marine protists, and there is a growing industrial interest in these organisms, particularly because some species, including strains belonging to the genus Aurantiochytrium, accumulate high levels of docosahexaenoic acid (DHA). Here, we report the draft genome sequence of Aurantiochytrium sp. T66 (ATCC PRA-276), with a size of 43 Mbp, and 11,683 predicted protein-coding sequences. The data has been deposited at DDBJ/EMBL/Genbank under the accession LNGJ00000000. The genome sequence will contribute new insight into DHA biosynthesis and regulation, providing a basis for metabolic engineering of thraustochytrids.

  2. BN-350 "Mirror System".

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, A. L. (Angela L.); Halbig, J. K. (James K.)

    2004-01-01

    The BN-350 Unattended Monitoring System plays an important role for the Safeguards Department of the International Atomic Energy Agency (IAEA). In 1998, the Los Alamos National Laboratory, in conjunction with the IAEA and sponsored by the US Department of Energy, designed and installed an integrated multi-instrument safeguards system at the BN-350 reactor in Aktau, Kazakhstan, to monitor spent-fuel and blanket assembly conditioning and canning activities. The purpose of the system was to provide effective safeguards at this facility while reducing the manpower load on the IAEA. The system is composed of many individual nondestructive analysis and surveillance components, each having a unique function and working together to provide fully unattended measurement of spent-fuel assemblies. The BN-350 ''Mirror System'' was built to provide a similar system with like components at the IAEA Headquarters in Vienna to facilitate analysis and/or simulation of problems that might occur in the field and for training inspectors and other technical staff in preparation for their work in the field. In addition, the system is used to test new equipment and qualify new or modified software. This paper describes the main components of the Mirror System, how the components are integrated, and how the Mirror System has benefited the IAEA.

  3. Direct conversion of h-BN into c-BN and formation of epitaxial c-BN/diamond heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Jagdish, E-mail: narayan@ncsu.edu; Bhaumik, Anagh; Xu, Weizong [Department of Materials Science and Engineering, Centennial Campus North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)

    2016-05-14

    We have created a new state of BN (named Q-BN) through rapid melting and super undercooling and quenching by using nanosecond laser pulses. Phase pure c-BN is formed either by direct quenching of super undercooled liquid or by nucleation and growth from Q-BN. Thus, a direct conversion of hexagonal boron nitride (h-BN) into phase-pure cubic boron nitride (c-BN) is achieved by nanosecond pulsed laser melting at ambient temperatures and atmospheric pressure in air. According to the P-T phase diagram, the transformation from h-BN into c-BN under equilibrium processing can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa or 3700 K/7.0 GPa with a recent theoretical refinement. Using nonequilibrium nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to the formation of a new phase, named as Q-BN. We present detailed characterization of Q-BN and c-BN layers by using Raman spectroscopy, high-resolution scanning electron microscopy, electron-back-scatter diffraction, high-resolution TEM, and electron energy loss spectroscopy, and discuss the mechanism of formation of nanodots, nanoneedles, microneedles, and single-crystal c-BN on sapphire substrate. We have also deposited diamond by pulsed laser deposition of carbon on c-BN and created c-BN/diamond heterostructures, where c-BN acts as a template for epitaxial diamond growth. We discuss the mechanism of epitaxial c-BN and diamond growth on lattice matching c-BN template under pulsed laser evaporation of amorphous carbon, and the impact of this discovery on a variety of applications.

  4. Bn and Si-Doped Bn Coatings on Woven Fabrics

    Science.gov (United States)

    Hurwitz, Frances I.; Scott, John M.; Wheeler, Donald R.; Chayka, Paul V.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    A computer controlled, pulsed chemical vapor infiltration (CVI) system has been developed to deposit BN from a liquid borazine (B3N3H6) source, as well as silicon doped BN coatings using borazine and a silicon source, into 2-D woven ceramic fabric preforms. The coating process was evaluated as a function of deposition temperature, pressure, and precursor flow rate. Coatings were characterized by field emission scanning electron microscopy, electron dispersive spectroscopy and Auger spectroscopy. By controlling the reactant feed ratios, Si incorporation could be controlled over the range of 6-24 atomic percent.

  5. 78 FR 38544 - Airworthiness Directives; B-N Group Ltd. Airplanes

    Science.gov (United States)

    2013-06-27

    ..., BN-2A-3, BN-2A- 6, BN-2A-8, BN-2A-9, BN-2B-20, BN-2B-21, BN-2B-26, BN-2B-27, BN-2T, and BN-2T-4R...-21, BN-2B-26, BN-2B-27, BN-2T, and BN-2T-4R airplanes, all serial numbers, certificated in any...

  6. (Fuzzy) Ideals of BN-Algebras

    Science.gov (United States)

    Walendziak, Andrzej

    2015-01-01

    The notions of an ideal and a fuzzy ideal in BN-algebras are introduced. The properties and characterizations of them are investigated. The concepts of normal ideals and normal congruences of a BN-algebra are also studied, the properties of them are displayed, and a one-to-one correspondence between them is presented. Conditions for a fuzzy set to be a fuzzy ideal are given. The relationships between ideals and fuzzy ideals of a BN-algebra are established. The homomorphic properties of fuzzy ideals of a BN-algebra are provided. Finally, characterizations of Noetherian BN-algebras and Artinian BN-algebras via fuzzy ideals are obtained. PMID:26125050

  7. Bias induced modulation of electrical and thermal conductivity and heat capacity of BN and BN/graphene bilayers

    Science.gov (United States)

    Chegel, Raad

    2017-04-01

    By using the tight binding approximation and Green function method, the electronic structure, density of state, electrical conductivity, heat capacity of BN and BN/graphene bilayers are investigated. The AA-, AB1- and AB2- BN/graphene bilayers have small gap unlike to BN bilayers which are wide band gap semiconductors. Unlike to BN bilayer, the energy gap of graphene/BN bilayers increases with external field. The magnitude of the change in the band gap of BN bilayers is much higher than the graphene/BN bilayers. Near absolute zero, the σ(T) is zero for BN bilayers and it increases with temperature until reaches maximum value then decreases. The BN/graphene bilayers have larger electrical conductivity larger than BN bilayers. For both bilayers, the specific heat capacity has a Schottky anomaly.

  8. Bias induced modulation of electrical and thermal conductivity and heat capacity of BN and BN/graphene bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Chegel, Raad, E-mail: Raad.chegel@gmail.com

    2017-04-15

    By using the tight binding approximation and Green function method, the electronic structure, density of state, electrical conductivity, heat capacity of BN and BN/graphene bilayers are investigated. The AA-, AB{sub 1}- and AB{sub 2}- BN/graphene bilayers have small gap unlike to BN bilayers which are wide band gap semiconductors. Unlike to BN bilayer, the energy gap of graphene/BN bilayers increases with external field. The magnitude of the change in the band gap of BN bilayers is much higher than the graphene/BN bilayers. Near absolute zero, the σ(T) is zero for BN bilayers and it increases with temperature until reaches maximum value then decreases. The BN/graphene bilayers have larger electrical conductivity larger than BN bilayers. For both bilayers, the specific heat capacity has a Schottky anomaly.

  9. Effects of BN content on the structural and mechanical properties of a-SiBN ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Ningbo; Xue, Wei; Zhou, Hongming; Zhang, Miao [Wenzhou Univ. (China). College of Mechanical and Electrical Engineering

    2013-02-15

    SiBN has the advantages of Si{sub 3}N{sub 4} at high temperature and also presents good mechanical properties. Understanding the structural and mechanical properties of SiBN is essential in order to control the properties under fabrication. In this paper, the effects of BN content on structural and mechanical properties of SiBN ceramics were investigated using atomistic simulation. Phase separation of the SiN-rich region and the BN-rich region was observed for all the three compositions. With BN content increases, the BN-rich regions tend to be larger and the SiN-rich regions become smaller. Interestingly, Si{sub 3}B{sub 3}N{sub 7} shows different structural and mechanical properties compared with Si{sub 3}BN{sub 5} and Si{sub 3}B{sub 5}N{sub 9}: (1) sharper and narrower peaks for pair distribution functions and angular distribution. (2) larger values but less stability for Young's moduli at high temperatures. The larger Young's modulus of Si{sub 3}B{sub 3}N{sub 7} is attributed to the network structure of BN and SiN phase. (orig.)

  10. Cellulose nanofibrils (CNF) filled boron nitride (BN) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Sulaiman, Hanisah Syed; Hua, Chia Chin; Zakaria, Sarani [School of Applied Physic, Faculty of Science and Technology, Universiti Kebangsaan Malaysia.43600 Bangi, Selangor (Malaysia)

    2015-09-25

    In this study, nanocomposite using cellulose nanofibrils filled with different percentage of boron nitride (CNF-BN) were prepared. The objective of this research is to study the effect of different percentage of BN to the thermal conductivity of the nanocomposite produced. The CNF-BN nanocomposite were characterization by FT-IR, SEM and thermal conductivity. The FT-IR analysis of the CNF-BN nanocomposite shows all the characteristic peaks of cellulose and BN present in all samples. The dispersion of BN in CNF were seen through SEM analysis. The effect of different loading percentage of BN to the thermal conductivity of the nanocomposite were also investigated.

  11. Spin transport in two-layer-CVD-hBN/graphene/hBN heterostructures

    Science.gov (United States)

    Gurram, M.; Omar, S.; Zihlmann, S.; Makk, P.; Li, Q. C.; Zhang, Y. F.; Schönenberger, C.; van Wees, B. J.

    2018-01-01

    We study room-temperature spin transport in graphene devices encapsulated between a layer-by-layer-stacked two-layer-thick chemical vapor deposition (CVD) grown hexagonal boron nitride (hBN) tunnel barrier, and a few-layer-thick exfoliated-hBN substrate. We find mobilities and spin-relaxation times comparable to that of SiO2 substrate-based graphene devices, and we obtain a similar order of magnitude of spin relaxation rates for both the Elliott-Yafet and D'Yakonov-Perel' mechanisms. The behavior of ferromagnet/two-layer-CVD-hBN/graphene/hBN contacts ranges from transparent to tunneling due to inhomogeneities in the CVD-hBN barriers. Surprisingly, we find both positive and negative spin polarizations for high-resistance two-layer-CVD-hBN barrier contacts with respect to the low-resistance contacts. Furthermore, we find that the differential spin-injection polarization of the high-resistance contacts can be modulated by dc bias from -0.3 to +0.3 V with no change in its sign, while its magnitude increases at higher negative bias. These features point to the distinctive spin-injection nature of the two-layer-CVD-hBN compared to the bilayer-exfoliated-hBN tunnel barriers.

  12. Complete Genome Sequences of Bovine Parainfluenza Virus Type 3 Strain BN-1 and Vaccine Strain BN-CE.

    Science.gov (United States)

    Ohkura, Takashi; Kokuho, Takehiro; Konishi, Misako; Kameyama, Ken-Ichiro; Takeuchi, Kaoru

    2013-01-01

    Bovine parainfluenza virus type 3 (BPIV3) is associated with upper respiratory disease in cattle in many countries. Here, we report the complete genome sequences of the BPIV3 BN-1 strain, isolated from cattle in Japan, and the BN-CE vaccine strain, derived from the BN-1 strain by passages in chicken embryo fibroblasts.

  13. Linear Assembles of BN Nanosheets, Fabricated in Polymer/BN Nanosheet Composite Film

    Directory of Open Access Journals (Sweden)

    Hong-Baek Cho

    2011-01-01

    Full Text Available Linear assembles of BN nanosheets (LABNs were fabricated in polysiloxane/BN nanosheet composite film under a high DC electric field. The hexagonal BN nanosheets were dispersed by sonication in a prepolymer mixture of polysiloxane followed by a high-speed mixing. The homogeneous suspension was cast on a spacer of microscale thickness and applied to a high DC electric field before it became cross-linked. X-ray diffraction, scanning electron microscopy, and digital microscopy revealed that LABNs formed in the polysiloxane matrix and that the BN nanosheets in the LABNs were aligned perpendicular to the film plane with high anisotropy. This is the first time that linear assemblies of nanosheets have been fabricated in an organic-inorganic hybrid film by applying a DC electric field. The enhanced thermal conductivity of the composite film is attributed to the LABNs. The LABN formation and heat conduction mechanisms are discussed. The polysiloxane/BN nanosheet composite film has the potential to be used semiconductor applications that require both a high thermal conductivity and a high electric insulation.

  14. Progress on BN and Doped-BN Coatings on Woven Fabrics

    Science.gov (United States)

    Hurwitz, Frances I.; Scott, John M.; Chayka, Paul V.

    2001-01-01

    A novel, multistep process for applying interface coatings to woven structures using a pulsed CVD process is being evaluated. Borazine (B3N3H6), a neat liquid, and several Si precursors are used in the process to produce BN and SiBN coatings on Hi- Nicalon fabrics and preforms. A three variable, two level, full factorial matrix is proposed to define the influence of processing parameters. Coating morphology, uniformity and chemistry are characterized by field emission scanning electron microscopy (FESEM), energy dispersive (EDS) and Auger spectroscopies.

  15. BN-600 full MOX core benchmark analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. I.; Hill, R. N.; Grimm, K.; Rimpault, G.; Newton, T.; Li, Z. H.; Rineiski, A.; Mohanakrishan, P.; Ishikawa, M.; Lee, K. B.; Danilytchev, A.; Stogov, V.; Nuclear Engineering Division; International Atomic Energy Agency; CEA/Cadarache; SERCO Assurance; China Inst. of Atomic Energy; Forschnungszentrum Karlsruhe; Indira Gandhi Centre for Atomic Research; Japan Nuclear Cycle Development Inst.; Korea Atomic Energy Research Inst.; Inst. of Physics and Power Engineering

    2004-01-01

    As a follow-up of the BN-600 hybrid core benchmark, a full MOX core benchmark was performed within the framework of the IAEA co-ordinated research project. Discrepancies between the values of main reactivity coefficients obtained by the participants for the BN-600 full MOX core benchmark appear to be larger than those in the previous hybrid core benchmarks on traditional core configurations. This arises due to uncertainties in the proper modelling of the axial sodium plenum above the core. It was recognized that the sodium density coefficient strongly depends on the core model configuration of interest (hybrid core vs. fully MOX fuelled core with sodium plenum above the core) in conjunction with the calculation method (diffusion vs. transport theory). The effects of the discrepancies revealed between the participants results on the ULOF and UTOP transient behaviours of the BN-600 full MOX core were investigated in simplified transient analyses. Generally the diffusion approximation predicts more benign consequences for the ULOF accident but more hazardous ones for the UTOP accident when compared with the transport theory results. The heterogeneity effect does not have any significant effect on the simulation of the transient. The comparison of the transient analyses results concluded that the fuel Doppler coefficient and the sodium density coefficient are the two most important coefficients in understanding the ULOF transient behaviour. In particular, the uncertainty in evaluating the sodium density coefficient distribution has the largest impact on the description of reactor dynamics. This is because the maximum sodium temperature rise takes place at the top of the core and in the sodium plenum.

  16. Thick c-BN coatings - Preparation, properties and application tests

    Energy Technology Data Exchange (ETDEWEB)

    Keunecke, M. [Fraunhofer Institute for Surface Engineering and Thin Films (IST), Braunschweig (Germany)]. E-mail: martin.keunecke@ist.fraunhofer.de; Wiemann, E. [Institute for Machine Tools and Factory Management (IWF), Berlin University of Technology (Germany); Weigel, K. [Fraunhofer Institute for Surface Engineering and Thin Films (IST), Braunschweig (Germany); Park, S.T. [Fraunhofer Institute for Surface Engineering and Thin Films (IST), Braunschweig (Germany); Bewilogua, K. [Fraunhofer Institute for Surface Engineering and Thin Films (IST), Braunschweig (Germany)

    2006-11-23

    Due to the outstanding properties of cubic boron nitride (c-BN) - c-BN is the second hardest of all known materials, has a high wear resistance and a high thermal stability - this material is very promising for a broad range of applications, especially for cutting tools, both as bulk and as a coating material. The state-of-the-art is the use of sintered cutting inserts with c-BN grains. Such c-BN grains are synthesized in an expensive high-pressure-high-temperature process. The requirements for cutting tools continuously increase in production engineering and this leads to a strong demand for new super hard tool coatings. Cubic boron nitride coatings could be an attractive solution. Unfortunately, the preparation of thick c-BN coatings, on the {mu}m scale, is difficult, due to some serious drawbacks and has been successful only in the last years for a few research groups worldwide. PVD processes allow the preparation of c-BN films thicker than 2 {mu}m on silicon and 1 {mu}m c-BN top layers on pre-coated cemented carbide cutting inserts. Measurements of mechanical properties like hardness and Young's modulus reveal that the properties of the c-BN coatings, with hardness of about 60 GPa, are nearly identical to those of c-BN bulk material. Results of systematic turning and milling tests of different coatings in combination with a c-BN top-layer on cemented carbide cutting inserts will be presented in detail. The new results confirm the high potential of c-BN coatings on cutting tools.

  17. Chemically stabilized epitaxial wurtzite-BN thin film

    Science.gov (United States)

    Vishal, Badri; Singh, Rajendra; Chaturvedi, Abhishek; Sharma, Ankit; Sreedhara, M. B.; Sahu, Rajib; Bhat, Usha; Ramamurty, Upadrasta; Datta, Ranjan

    2018-03-01

    We report on the chemically stabilized epitaxial w-BN thin film grown on c-plane sapphire by pulsed laser deposition under slow kinetic condition. Traces of no other allotropes such as cubic (c) or hexagonal (h) BN phases are present. Sapphire substrate plays a significant role in stabilizing the metastable w-BN from h-BN target under unusual PLD growth condition involving low temperature and pressure and is explained based on density functional theory calculation. The hardness and the elastic modulus of the w-BN film are 37 & 339 GPa, respectively measured by indentation along direction. The results are extremely promising in advancing the microelectronic and mechanical tooling industry.

  18. Determination of micro structural corrosion by BN

    Energy Technology Data Exchange (ETDEWEB)

    Zergoug, M.; Kamel, G.; Benchaala, A. [Laboratoire d' Electronique et d' Electrotechnique, Centre de soudage et de controle, Route de Dely Ibrahim, B.P:64, Cheraga (Algeria)

    2004-07-01

    The quality control of industrial components requires adaptation and the development of new material characterization and particular non destructive testing techniques. To characterize steel, it would be useful to know its chemical composition, physic-chemical constitution, metallurgical state (annealed, hammered) and other parameters (superficial and chemical processing, etc.). The testing method using Barkhausen noise (B.N.) is a particular method, which can be applied on ferromagnetic materials. It is a magnetic non destructive evaluation (NDE) method and can provide very important information about the material microstructure. The work here presented documents the ability to determine the metallurgical state of steel submitted to the corrosive attack by electrochemical process. The samples are characterized by Barkhausen noise as non destructive methods and are compared with methods as metallography, micro hardness measurement, and toughness determination. (authors)

  19. Calculated carrier mobility of h-BN/γ-InSe/h-BN van der Waals heterostructures

    Science.gov (United States)

    Kang, P.; Michaud-Rioux, V.; Kong, X.-H.; Yu, G.-H.; Guo, H.

    2017-12-01

    Recent experiments reported excellent transport properties of two-dimensional (2D) van der Waals (vdW) heterostructures made of atomically thin InSe layers encapsulated by two hBN capping layers (ISBN). The carrier mobility of the ISBN films exceeded μ ∼ 1.2× {{10}4} \\text{c}{{\\text{m}}2} {{\\text{V}}-1} {{\\text{s}}-1} at low temperature, much higher than that of pristine InSe films. It has been puzzling why the relatively inert hBN capping layer could so drastically enhance mobility of the ISBN composite. Using a state-of-the-art first principles method, we have calculated phonon limited carrier mobility of 18 different ISBN films and 6 pristine InSe films with different thicknesses, the largest system containing 2212 atoms. The hBN capping layer significantly alters the elastic stiffness coefficient as compared with pure InSe—thus the acoustic phonons in the ISBN composite—giving rise to the observed large mobility of ISBN films. Of the 18 calculated ISBN films, the ones with no strain at the hBN/InSe interface possess the highest electron mobility, reaching 4340~\\text{c}{{\\text{m}}2}~{{\\text{V}}-1}~{{\\text{s}}-1} at room temperature, which could easily go over {{10}4}~\\text{c}{{\\text{m}}2}~{{\\text{V}}-1}~{{\\text{s}}-1} at low temperatures. We conclude that the mechanical properties of the composite 2D vdW ISBN material play the crucial role for inducing the large carrier mobility, a principle that could be applied to many other 2D vdW heterostructures.

  20. Tribological properties of epoxy composite coatings reinforced with functionalized C-BN and H-BN nanofillers

    Science.gov (United States)

    Yu, Jingjing; Zhao, Wenjie; Wu, Yinghao; Wang, Deliang; Feng, Ruotao

    2018-03-01

    A series of epoxy resin (EP) composite coatings reinforced with functionalized cubic boron nitride (FC-BN) and functionalized hexagonal boron nitride (FH-BN) were fabricated successfully on 316L stainless steel by hand lay-up technique. The structure properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The morphologies were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, UMT-3 tribometer and surface profiler were used to investigate tribological behaviors of as-prepared composite coatings under dry friction and seawater conditions respectively. The results demonstrated that the presence of FC-BN or FH-BN fillers could greatly decrease the friction coefficient (COF) and wear rate of epoxy, in addition, composite coatings possess better tribological properties under seawater condition which was attributed to the lubricating effect of seawater. Moreover, FC-BN endows the composite coatings the highest wear resistance, and FH-BN /EP composite coatings exhibited the best friction reduction performance which is attributed to the self-lubricating performance of lamella structure for FH-BN sheet.

  1. A theoretical study on monoatomic BN nanochains and nanorings.

    Science.gov (United States)

    Rizi, Rouhollah Namazi; Noei, Maziar

    2016-09-01

    Boron nitride (BN) nanochains were successfully synthesized recently. In this work, we investigate the electronic, energetic, and structural properties of BN nanochains and nanorings by means of density functional theory calculations. Our calculations support the experimental findings and offer additional physical insights into these new nanostructured materials. We show that BN nanochains are biracial compounds that tend to be closed and form a ring. They have single and double bonds alternately throughout the chain. The boron atoms are not saturated and are strong Lewis acids. Increase in the length of the chain tends to result in the conversion from a semiconductor to a semimetal material. The ring structures are stabler than the corresponding chains, and unlike the chains these structures are predicted to be insulators. The binding energy of the chains and rings increases with an increase in their size. Rings with odd or even numbers of BN units show different electronic properties.

  2. Introducing lattice strain to graphene encapsulated in hBN

    Science.gov (United States)

    Tomori, Hikari; Hiraide, Rineka; Ootuka, Youiti; Watanabe, Kenji; Taniguchi, Takashi; Kanda, Akinobu

    Due to the characteristic lattice structure, lattice strain in graphene produces an effective gauge field. Theories tell that by controlling spatial variation of lattice strain, one can tailor the electronic state and transport properties of graphene. For example, under uniaxial local strain, graphene exhibits a transport gap at low energies, which is attractive for a graphene application to field effect devices. Here, we develop a method for encapsulating a strained graphene film in hexagonal boron-nitride (hBN). It is known that the graphene carrier mobility is significantly improved by the encapsulation of graphene in hBN, which has never been applied to strained graphene. We encapsulate graphene in hBN using the van der Waals assembly method. Strain is induced by sandwiching a graphene film between patterned hBN sheets. Spatial variation of strain is confirmed with micro Raman spectroscopy. Transport measurement of encapsulated strained graphene is in progress.

  3. A comparative computational study on the BN ring doped nanographenes

    Energy Technology Data Exchange (ETDEWEB)

    Vessally, E. [Department of Chemistry, Payame Noor University, Tehran (Iran, Islamic Republic of); Soleimani-Amiri, S. [Department of Chemistry, Karaj Branch, Islamic Azad University, Karaj (Iran, Islamic Republic of); Hosseinian, A. [Department of Engineering Science, College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of); Edjlali, L., E-mail: l_edjlali@iaut.ac.ir [Department of Chemistry, Tabriz Branch, Islamic Azad University, Tabriz (Iran, Islamic Republic of); Bekhradnia, A. [Pharmaceutical Sciences Research Center, Department of Medicinal Chemistry, Mazandaran University of Medical Sciences, Sari (Iran, Islamic Republic of)

    2017-02-28

    Highlights: • Clar’s sextet rule determine the relative stability of HBC nanographenes. • Coronene-like doping increases the electrical conductivity of the HBC. • Frenkel type exciton binding energy is predicted for HBC nanographenes. - Abstract: The electronic, optical, energetic, and structural properties of a HBC (hexa-peri-hexabenzocoronene) nanographene and its central benzene- and coronene-like BN substituted forms, and also full BN analogue were investigated using density functional theory. It was found that a larger number of carbon atoms cause a more negative cohesive energy and, thereby a greater structural stability. Our nucleus independent chemical shift analysis indicates that the aromaticity and Clar’s sextet rule determine the relative stability of these structures. The benzene-like or coronene-like doping makes the HBC more insulator or semiconductor. Electron-hole Frenkel type exciton binding energy was predicted and calculated to be nearly identical for all nanographenes in the range of 0.61–0.69 eV. The coronene-like BN-doped HBC (BN2-HBN) shows higher conductivity due to very narrow optical and HOMO-LUMO energy gap. Partial density of states analysis indicates that the BN2-HBC electronically can be assumed a full BN whose peripheral atoms are replaced by carbon atoms. These carbon atoms are responsible for new states which are appeared within the gap.

  4. h-BN-TiO2 Nanocomposite for Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Václav Štengl

    2016-01-01

    Full Text Available h-BN-TiO2 nanocomposites were synthesized by the thermal hydrolysis of titanium peroxo-complexes in the presence of exfoliated h-BN. The bulk h-BN was prepared by annealing mixture of boric acid and urea, and high intensity ultrasound was used for its exfoliation. The prepared samples were characterized by X-ray powder diffraction (XRD, infrared spectroscopy, Raman spectroscopy, electron spin resonance (ESR, high resolution electron microscopy, BET surface area, and BJH porosity measurement. The UV-Vis diffuse reflectance spectroscopy was employed to estimate band-gap energies. The photoinduced charge on the surface of h-BN-TiO2 nanocomposites was visualized using electric force microscopy (EFM. The photocatalytic activity was determined by azo dyes Orange II and Reactive Black 5 photobleaching. The highest rate constant k = 0.0762 min−1 and 0.0164 min−1, under UV and visible light irradiation, respectively, showed sample denoted TiP050BN with moderate concentration of h-BN.

  5. Enhancement of surface mechanical properties by using TiN[BCN/BN]{sub n}/c-BN multilayer system

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, H. [Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia); Caicedo, J.C., E-mail: Jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Amaya, C. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Munoz-Saldana, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Mexico (Mexico); Yate, L.; Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Prieto, P. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Centro de Excelencia en Nuevos Materiales, CENM, Cali (Colombia)

    2010-11-15

    The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN]{sub n}/c-BN multilayer system as a protective coating. TiN[BCN/BN]{sub n}/c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period ({Lambda}) and the number of bilayers (n) because one bilayer (n = 1) represents two different layers (t{sub BCN} + t{sub BN}), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm{sup -1} and 1100 cm{sup -1}, respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number (n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period ({Lambda}) was 80 nm (n = 25), yielding the relative highest hardness ({approx}30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to

  6. Enhancement of surface mechanical properties by using TiN[BCN/BN] n/c-BN multilayer system

    Science.gov (United States)

    Moreno, H.; Caicedo, J. C.; Amaya, C.; Muñoz-Saldaña, J.; Yate, L.; Esteve, J.; Prieto, P.

    2010-11-01

    The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN] n/c-BN multilayer system as a protective coating. TiN[BCN/BN] n/c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period ( Λ) and the number of bilayers ( n) because one bilayer ( n = 1) represents two different layers ( tBCN + tBN), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm -1 and 1100 cm -1, respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number ( n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period ( Λ) was 80 nm ( n = 25), yielding the relative highest hardness (˜30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to multilayered coatings to explain this

  7. Investigation on two abnormal phenomena about thermal conductivity enhancement of BN/EG nanofluids

    Directory of Open Access Journals (Sweden)

    Wu Jiangtao

    2011-01-01

    Full Text Available Abstract The thermal conductivity of boron nitride/ethylene glycol (BN/EG nanofluids was investigated by transient hot-wire method and two abnormal phenomena was reported. One is the abnormal higher thermal conductivity enhancement for BN/EG nanofluids at very low-volume fraction of particles, and the other is the thermal conductivity enhancement of BN/EG nanofluids synthesized with large BN nanoparticles (140 nm which is higher than that synthesized with small BN nanoparticles (70 nm. The chain-like loose aggregation of nanoparticles is responsible for the abnormal increment of thermal conductivity enhancement for the BN/EG nanofluids at very low particles volume fraction. And the difference in specific surface area and aspect ratio of BN nanoparticles may be the main reasons for the abnormal difference between thermal conductivity enhancements for BN/EG nanofluids prepared with 140- and 70-nm BN nanoparticles, respectively.

  8. Monte Carlo Generation of the 2BN Bremsstrahlung Distribution

    CERN Document Server

    Peralta, L; Trindade, A

    2003-01-01

    The 2BN bremsstrahlung cross-section is a well-adapted distribution to describe the radiative processes at low electron kinetic energy (Ek<500 keV). In this work a method to implement this distribution in a Monte Carlo generator is developed.

  9. Larvicidal activity of Illicium difengpi BN Chang (Schisandraceae ...

    African Journals Online (AJOL)

    /tjpr.v14i1.15. Original Research Article. Larvicidal activity of Illicium difengpi BN Chang. (Schisandraceae) Stem Bark and its Constituent. Compounds against Aedes aegypti L. Ying Liu1,2,3, Xin Chao Liu1, Qi Yong Liu2, Chang Niu3 and Zhi ...

  10. Larvicidal activity of Illicium difengpi BN Chang (Schisandraceae ...

    African Journals Online (AJOL)

    Purpose: To determine the larvicidal activity of the essential oil derived from Illicium difengpi B.N. Chang stem bark (Schisandraceae) and its major constituents against the larvae of Aedes aegypti L. Methods: Essential oil of I. difengpi stem bark was obtained by hydrodistillation and analyzed by gas chromatography (GC) ...

  11. Further delays hit troubled $2bn cosmic-ray detector

    CERN Multimedia

    Cartlidge, Edwin

    2010-01-01

    "A $2bn mission to study cosmic rays will have to wait another few months before being sent to the International Space Station (ISS) after NASA announced last month that it was pushing back the launch of the Space Shuttle Endeavour until 26 February 2011" (0.5 page)

  12. The interaction of phosgene gas with different BN nanocones: DFT studies

    Science.gov (United States)

    Vessally, Esmail; Salary, Mina; Arshadi, Sattar; Hosseinian, Akram; Edjlali, Ladan

    2018-01-01

    We investigated the interaction of a phosgene molecule with four kinds of BN nanocones with 60°, 120°, 180° and 240° disclination angles using density functional theory calculations. Based on the results, the phosgene molecule tends to be adsorbed on the apex of all BN nanocones with adsorption energies of -11.1, -4.6, -16.6, and -14.8 kcal/mol, respectively. It was predicted that both of low coordination B atom, and Bsbnd B antiphase defects stabilize the LUMO level of the BN nanocones, and make them more reactive to phosgene gas. The electrical conductivity of the BN nanocone with 60° disclination angle will not change at the presence of the phosgene; and it cannot be used as a sensor. But the electrical conductivity of the BN nanocones with 120°, 180° and 240° disclination angles significantly increases. Therefore, these nanocones may be promising candidates for application in phosgene sensors. We found that the order of electronic sensitivity of the BN nanocones toward the phosgene gas is as follows: BN-240 > BN-120 > BN-180 » BN-60. The recovery time for the BN nanocones with 60°, 120°, 180° and 240° disclination angles is about 4.5 × 10-5, 7.8 × 10-10, 0.48, and 0.02 s at 298 K, respectively, indicating that the BN nanocones benefit from a short recovery time as chemical sensors.

  13. Electrophoretic Deposition of Chitosan/h-BN and Chitosan/h-BN/TiO2 Composite Coatings on Stainless Steel (316L) Substrates

    OpenAIRE

    Raddaha, Namir S.; Luis Cordero-Arias; Sandra Cabanas-Polo; Sannakaisa Virtanen; Roether, Judith A; Boccaccini, Aldo R.

    2014-01-01

    This article presents the results of an experimental investigation designed to deposit chitosan/hexagonal boron nitride (h-BN) and chitosan/h-BN/titania (TiO2) composites on SS316L substrates using electrophoretic deposition (EPD) for potential antibacterial applications. The influence of EPD parameters (voltage and deposition time) and relative concentrations of chitosan, h-BN and TiO2 in suspension on deposition yield was studied. The composition and structure of deposited coatings were inv...

  14. Microstructure and mechanical properties of SiO2-BN ceramic and Invar alloy joints brazed with Ag–Cu–Ti+TiH2+BN composite filler

    OpenAIRE

    Y. Wang; Z.W. Yang; L.X. Zhang; D.P. Wang; J.C. Feng

    2016-01-01

    Ag–Cu–Ti + TiH2+BN composite filler was prepared to braze SiO2-BN ceramic and Invar alloy. The interfacial microstructure, mechanical properties, and residual stress distribution of the brazed joints were investigated. The results show that a wave-like Fe2Ti–Ni3Ti structure appears in the Invar substrate and a thin TiN–TiB2 reaction layer forms adjacent to the SiO2-BN ceramic. The added BN particles react with Ti to form TiN–TiB fine-particles, which is beneficial to refine the microstructure...

  15. Mode of action of RNase BN/RNase Z on tRNA precursors: RNase BN does not remove the CCA sequence from tRNA.

    Science.gov (United States)

    Dutta, Tanmay; Deutscher, Murray P

    2010-07-23

    RNase BN, the Escherichia coli homolog of RNase Z, was previously shown to act as both a distributive exoribonuclease and an endoribonuclease on model RNA substrates and to be inhibited by the presence of a 3'-terminal CCA sequence. Here, we examined the mode of action of RNase BN on bacteriophage and bacterial tRNA precursors, particularly in light of a recent report suggesting that RNase BN removes CCA sequences (Takaku, H., and Nashimoto, M. (2008) Genes Cells 13, 1087-1097). We show that purified RNase BN can process both CCA-less and CCA-containing tRNA precursors. On CCA-less precursors, RNase BN cleaved endonucleolytically after the discriminator nucleotide to allow subsequent CCA addition. On CCA-containing precursors, RNase BN acted as either an exoribonuclease or endoribonuclease depending on the nature of the added divalent cation. Addition of Co(2+) resulted in higher activity and predominantly exoribonucleolytic activity, whereas in the presence of Mg(2+), RNase BN was primarily an endoribonuclease. In no case was any evidence obtained for removal of the CCA sequence. Certain tRNA precursors were extremely poor substrates under any conditions tested. These findings provide important information on the ability of RNase BN to process tRNA precursors and help explain the known physiological properties of this enzyme. In addition, they call into question the removal of CCA sequences by RNase BN.

  16. Biological Efficacy of Streptomyces sp. Strain BN1 against the Cereal Head Blight Pathogen Fusarium graminearum

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-03-01

    Full Text Available Fusarium head blight (FHB caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed.

  17. Solid Oxide Fuel Cell Seal Glass - BN Nanotubes Composites

    Science.gov (United States)

    Bansal, Narottam P.; Choi, Sung R.; Hurst, Janet B.; Garg, Anita

    2005-01-01

    Solid oxide fuel cell seal glass G18 composites reinforced with approx.4 weight percent of BN nanotubes were fabricated via hot pressing. Room temperature strength and fracture toughness of the composite were determined by four-point flexure and single edge V-notch beam methods, respectively. The strength and fracture toughness of the composite were higher by as much as 90% and 35%, respectively, than those of the glass G18. Microscopic examination of the composite fracture surfaces using SEM and TEM showed pullout of the BN nanotubes, similar in feature to fiber-reinforced ceramic matrix composites with weak interfaces. Other mechanical and physical properties of the composite will also be presented.

  18. H-1 Upgrades (4BW/4BN) (H-1 Upgrades)

    Science.gov (United States)

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-101 H-1 Upgrades (4BW/4BN) (H-1 Upgrades) As of FY 2017 President’s Budget Defense...5 Mission and Description 6 Executive Summary 7 Threshold Breaches 8 Schedule 9 Performance 11 Track to Budget 16 Cost and...Funding 17 Low Rate Initial Production 26 Foreign Military Sales 27 Nuclear Costs 27 Unit Cost 28 Cost Variance 31 Contracts

  19. Stability and electronic properties of Gex(BN)y monolayers

    Science.gov (United States)

    Freitas, A.; Machado, L. D.; Tromer, R. M.; Bezerra, C. G.; Azevedo, S.

    2017-10-01

    In this work, we employ ab initio simulations to propose a new class of monolayers with stoichiometry Gex(BN)y . These monolayers belong to a family of 2D materials combining B, N and group IV atoms, such as BxCyNz and SixByNz . We calculated the formation energy for ten atomic arrangements, and found that it increases when the number of Bsbnd Ge and Nsbnd Ge bonds increases, and decreases when the number of Bsbnd N and Gesbnd Ge bonds increases. We found that the lowest energy monolayer presented a Ge2 BN stoichiometry, and maximized the number of Bsbnd N and Gesbnd Ge bonds. This structure also presented mixed sp2 and sp3 bonds and out-of-plane buckling. Moreover, it remained stable in our ab initio molecular dynamics simulations carried out at T = 300 K. The calculated electronic properties revealed that Gex(BN)y monolayers might present conductor or semiconductor behavior, with band gaps ranging from 0.0 to 0.74 eV, depending on atomic arrangement. Tunable values of band gap can be useful in applications. In optoelectronics, for instance, this property might be employed to control absorbed light wavelengths. Our calculations add a new class of monolayers to the increasing library of 2D materials.

  20. Electrophoretic Deposition of Chitosan/h-BN and Chitosan/h-BN/TiO₂ Composite Coatings on Stainless Steel (316L) Substrates.

    Science.gov (United States)

    Raddaha, Namir S; Cordero-Arias, Luis; Cabanas-Polo, Sandra; Virtanen, Sannakaisa; Roether, Judith A; Boccaccini, Aldo R

    2014-03-04

    This article presents the results of an experimental investigation designed to deposit chitosan/hexagonal boron nitride (h-BN) and chitosan/h-BN/titania (TiO₂) composites on SS316L substrates using electrophoretic deposition (EPD) for potential antibacterial applications. The influence of EPD parameters (voltage and deposition time) and relative concentrations of chitosan, h-BN and TiO₂ in suspension on deposition yield was studied. The composition and structure of deposited coatings were investigated by FTIR, XRD and SEM. It was observed that h-BN and TiO₂ particles were dispersed in the chitosan matrix through simultaneous deposition. The adhesion between the electrophoretic coatings and the stainless steel substrates was tested by using tape test technique, and the results showed that the adhesion strength corresponded to 3B and 4B classes. Corrosion resistance was evaluated by electrochemical polarization curves, indicating enhanced corrosion resistance of the chitosan/h-BN/TiO₂ and chitosan/h-BN coatings compared to the bare stainless steel substrate. In order to investigate the in-vitro inorganic bioactivity, coatings were immersed in simulated body fluid (SBF) for 28 days. FTIR and XRD results showed no formation of hydroxyapatite on the surface of chitosan/h-BN/TiO₂ and chitosan/h-BN coatings, which are therefore non bioactive but potentially useful as antibacterial coatings.

  1. Electrophoretic Deposition of Chitosan/h-BN and Chitosan/h-BN/TiO2 Composite Coatings on Stainless Steel (316L Substrates

    Directory of Open Access Journals (Sweden)

    Namir S. Raddaha

    2014-03-01

    Full Text Available This article presents the results of an experimental investigation designed to deposit chitosan/hexagonal boron nitride (h-BN and chitosan/h-BN/titania (TiO2 composites on SS316L substrates using electrophoretic deposition (EPD for potential antibacterial applications. The influence of EPD parameters (voltage and deposition time and relative concentrations of chitosan, h-BN and TiO2 in suspension on deposition yield was studied. The composition and structure of deposited coatings were investigated by FTIR, XRD and SEM. It was observed that h-BN and TiO2 particles were dispersed in the chitosan matrix through simultaneous deposition. The adhesion between the electrophoretic coatings and the stainless steel substrates was tested by using tape test technique, and the results showed that the adhesion strength corresponded to 3B and 4B classes. Corrosion resistance was evaluated by electrochemical polarization curves, indicating enhanced corrosion resistance of the chitosan/h-BN/TiO2 and chitosan/h-BN coatings compared to the bare stainless steel substrate. In order to investigate the in-vitro inorganic bioactivity, coatings were immersed in simulated body fluid (SBF for 28 days. FTIR and XRD results showed no formation of hydroxyapatite on the surface of chitosan/h-BN/TiO2 and chitosan/h-BN coatings, which are therefore non bioactive but potentially useful as antibacterial coatings.

  2. Electrophoretic Deposition of Chitosan/h-BN and Chitosan/h-BN/TiO2 Composite Coatings on Stainless Steel (316L) Substrates

    Science.gov (United States)

    Raddaha, Namir S.; Cordero-Arias, Luis; Cabanas-Polo, Sandra; Virtanen, Sannakaisa; Roether, Judith A.; Boccaccini, Aldo R.

    2014-01-01

    This article presents the results of an experimental investigation designed to deposit chitosan/hexagonal boron nitride (h-BN) and chitosan/h-BN/titania (TiO2) composites on SS316L substrates using electrophoretic deposition (EPD) for potential antibacterial applications. The influence of EPD parameters (voltage and deposition time) and relative concentrations of chitosan, h-BN and TiO2 in suspension on deposition yield was studied. The composition and structure of deposited coatings were investigated by FTIR, XRD and SEM. It was observed that h-BN and TiO2 particles were dispersed in the chitosan matrix through simultaneous deposition. The adhesion between the electrophoretic coatings and the stainless steel substrates was tested by using tape test technique, and the results showed that the adhesion strength corresponded to 3B and 4B classes. Corrosion resistance was evaluated by electrochemical polarization curves, indicating enhanced corrosion resistance of the chitosan/h-BN/TiO2 and chitosan/h-BN coatings compared to the bare stainless steel substrate. In order to investigate the in-vitro inorganic bioactivity, coatings were immersed in simulated body fluid (SBF) for 28 days. FTIR and XRD results showed no formation of hydroxyapatite on the surface of chitosan/h-BN/TiO2 and chitosan/h-BN coatings, which are therefore non bioactive but potentially useful as antibacterial coatings. PMID:28788541

  3. Band gap engineering of chemical vapor deposited graphene by in situ BN doping.

    Science.gov (United States)

    Chang, Cheng-Kai; Kataria, Satender; Kuo, Chun-Chiang; Ganguly, Abhijit; Wang, Bo-Yao; Hwang, Jeong-Yuan; Huang, Kay-Jay; Yang, Wei-Hsun; Wang, Sheng-Bo; Chuang, Cheng-Hao; Chen, Mi; Huang, Ching-I; Pong, Way-Faung; Song, Ker-Jar; Chang, Shoou-Jinn; Guo, Jing-Hua; Tai, Yian; Tsujimoto, Masahiko; Isoda, Seiji; Chen, Chun-Wei; Chen, Li-Chyong; Chen, Kuei-Hsien

    2013-02-26

    Band gap opening and engineering is one of the high priority goals in the development of graphene electronics. Here, we report on the opening and scaling of band gap in BN doped graphene (BNG) films grown by low-pressure chemical vapor deposition method. High resolution transmission electron microscopy is employed to resolve the graphene and h-BN domain formation in great detail. X-ray photoelectron, micro-Raman, and UV-vis spectroscopy studies revealed a distinct structural and phase evolution in BNG films at low BN concentration. Synchrotron radiation based XAS-XES measurements concluded a gap opening in BNG films, which is also confirmed by field effect transistor measurements. For the first time, a significant band gap as high as 600 meV is observed for low BN concentrations and is attributed to the opening of the π-π* band gap of graphene due to isoelectronic BN doping. As-grown films exhibit structural evolution from homogeneously dispersed small BN clusters to large sized BN domains with embedded diminutive graphene domains. The evolution is described in terms of competitive growth among h-BN and graphene domains with increasing BN concentration. The present results pave way for the development of band gap engineered BN doped graphene-based devices.

  4. nBn Infrared Detector Containing Graded Absorption Layer

    Science.gov (United States)

    Gunapala, Sarath D.; Ting, David Z.; Hill, Cory J.; Bandara, Sumith V.

    2009-01-01

    It has been proposed to modify the basic structure of an nBn infrared photodetector so that a plain electron-donor- type (n-type) semiconductor contact layer would be replaced by a graded n-type III V alloy semiconductor layer (i.e., ternary or quarternary) with appropriate doping gradient. The abbreviation nBn refers to one aspect of the unmodified basic device structure: There is an electron-barrier ("B" ) layer between two n-type ("n" ) layers, as shown in the upper part of the figure. One of the n-type layers is the aforementioned photon-absorption layer; the other n-type layer, denoted the contact layer, collects the photocurrent. The basic unmodified device structure utilizes minority-charge-carrier conduction, such that, for reasons too complex to explain within the space available for this article, the dark current at a given temperature can be orders of magnitude lower (and, consequently, signal-to-noise ratios can be greater) than in infrared detectors of other types. Thus, to obtain a given level of performance, less cooling (and, consequently, less cooling equipment and less cooling power) is needed. [In principle, one could obtain the same advantages by means of a structure that would be called pBp because it would include a barrier layer between two electron-acceptor- type (p-type) layers.] The proposed modifications could make it practical to utilize nBn photodetectors in conjunction with readily available, compact thermoelectric coolers in diverse infrared- imaging applications that could include planetary exploration, industrial quality control, monitoring pollution, firefighting, law enforcement, and medical diagnosis.

  5. Modeling Environmental Degradation of SiC/BN/SiC CMCs (Preprint)

    Science.gov (United States)

    2017-04-28

    AFRL-RX-WP-JA-2017-0308 MODELING ENVIRONMENTAL DEGRADATION OF SIC/BN/SIC CMCS (PREPRINT) Craig Przybyla and Michael K Cinibulk...2017 Interim 22 July 2013 – 6 January 2017 4. TITLE AND SUBTITLE MODELING ENVIRONMENTAL DEGRADATION OF SIC/BN/SIC CMCS (PREPRINT) 5a. CONTRACT...91360 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39-18 Modeling environmental degradation of SiC/BN/SiC CMCs Triplicane A

  6. On the Stability of c-BN-Reinforcing Particles in Ceramic Matrix Materials

    Directory of Open Access Journals (Sweden)

    Anne-Kathrin Wolfrum

    2018-02-01

    Full Text Available Cubic boron nitride (c-BN composites produced at high pressures and temperatures are widely used as cutting tool materials. The advent of new, effective pressure-assisted densification methods, such as spark plasma sintering (SPS, has stimulated attempts to produce these composites at low pressures. Under low-pressure conditions, however, transformation of c-BN to the soft hexagonal BN (h-BN phase can occur, with a strong deterioration in hardness and wear. In the present work, the influence of secondary phases (B2O3, Si3N4, and oxide glasses on the transformation of c-BN was studied in the temperature range between 1100 °C and 1575 °C. The different heat treated c-BN particles and c-BN composites were analyzed by SEM, X-ray diffraction, and Raman spectroscopy. The transformation mechanism was found to be kinetically controlled solution–diffusion–precipitation. Given a sufficiently low liquid phase viscosity, the transformation could be observed at temperatures as low as 1200 °C for the c-BN–glass composites. In contrast, no transformation was found at temperatures up to 1575 °C when no liquid oxide phase is present in the composite. The results were compared with previous studies concerning the c-BN stability and the c-BN phase diagram.

  7. Optical pump-THz probe measurements of self-assembled h-BN/G heterostructures

    Science.gov (United States)

    Murali Krishna, M. Bala; Catherine, C.; Harada, T.; Soumya, V.; Taha-Tijerrina, J.; Nguyen, P.; Chang, P.; Ajayan, P. M.; Narayanan, N. T.; Dani, K. M.

    2014-03-01

    Two dimensional materials have attracted significant interest in recent times due to properties like large electron mobility, extreme thermal conductivity and high young's modulus. The potential of combining different two-dimensional materials to form new heterostructures with new functionality offers intriguing possibilities. Here, we study the opto-electronic properties of new types of solids consisting of randomly stacked layers of hexagonal boron nitride (h-BN) and graphene (G). We prepare these artificially stacked h-BN/G solids with different ratios of h-BN and G by mixing dispersions of exfoliated h-BN layers and graphene in different concentrations and allowing the exfoliated flakes to form the h-BN/G solids via van der Waals interaction. We study the ultrafast photocarrier dynamics in these solids by pumping with femtosecond visible-near-infrared pulses of light, and probing the transient photo-conductivity with sub-picosecond Terahertz pulses. As we tune the ratio of h-BN and G in the new h-BN/G solids, we not only observe opto-electronic properties that tune from the insulating h-BN phase to semi-metallic G phase, but we also see unique behavior, distinct from either phase, for certain h-BN/G ratios in between the two extreme phases.

  8. Bandgap oscillation in quasiperiodic (BN)xCy nanotubes

    Science.gov (United States)

    Freitas, A.; Bezerra, C. G.; Azevedo, S.; Machado, L. D.; Pedreira, D. O.

    2016-12-01

    In the present contribution, we apply first-principles calculations to study the effects of quasiperiodic disorder on the physical properties of BN and C nanotubes. We take BN nanotubes (BNNTs) and C nanotubes (CNTs) as building blocks and construct quasiperiodic BNxCy nanotubes according to the Fibonacci sequence. We studied armchair and zigzag nanotubes of varying diameters. Our results demonstrate that the energy gap oscillates as a function of the n-generation index of the Fibonacci sequence. Moreover, we show that the choice of the BNNTs and CNTs may lead to a quasiperiodic BNxCy nanotube presenting an adjustable energy gap. We obtained a variety of quasiperiodic nanotubes with energy gaps ranging from 0.29 eV to 1.06 eV, which may be of interest for specific technological applications. Finally, it is also demonstrated that the specific heat of the quasiperiodic zigzag and armchair nanotubes presents an oscillatory behavior in the low temperature regime, and that this behavior depends on the curvature of the nanotube.

  9. Parabolic starlike mappings of the unit ball $B^n$

    Directory of Open Access Journals (Sweden)

    Samira Rahrovi

    2016-02-01

    Full Text Available Let $f$ be a locally univalent function on the unit disk $U$. We consider the normalized extensions of $f$ to the Euclidean unit ball $B^nsubseteqmathbb{C}^n$ given by$$Phi_{n,gamma}(f(z=left(f(z_1,(f'(z_1^gammahat{z}right,$$ where $gammain[0,1/2]$, $z=(z_1,hat{z}in B^n$ and$$Psi_{n,beta}(f(z=left(f(z_1,(frac{f(z_1}{z_1}^betahat{z}right,$$in which $betain[0,1]$, $f(z_1neq 0$ and $z=(z_1,hat{z}inB^n$. In the case $gamma=1/2$, the function $Phi_{n,gamma}(f$ reduces to the well known Roper-Suffridge extension operator. By using different methods, we prove that if $f$ is parabolic starlike mapping on $U$ then $Phi_{n,gamma}(f$ and $Psi_{n,beta}(f$ are parabolic starlike mappings on $B^n$.

  10. Overexpression of BnWRKY33 in oilseed rape enhances resistance to Sclerotinia sclerotiorum.

    Science.gov (United States)

    Wang, Zheng; Fang, Hedi; Chen, Yu; Chen, Keping; Li, Guanying; Gu, Shoulai; Tan, Xiaoli

    2014-09-01

    Sclerotinia sclerotiorum causes a devastating disease in oilseed rape (Brassica napus) resulting in a tremendous yield loss worldwide. Studies on various host-pathogen interactions have shown that plant WRKY transcription factors are essential for defence. For the B. napus-S. sclerotiorum interaction, little direct evidence has been found with regard to the biological roles of specific WRKY genes in host resistance. In this study, we isolated a B. napus WRKY gene, BnWRKY33, and found that the gene is highly responsive to S. sclerotiorum infection. Transgenic B. napus plants overexpressing BnWRKY33 showed markedly enhanced resistance to S. sclerotiorum, constitutive activation of the expression of BnPR1 and BnPDF1.2, and inhibition of H2 O2 accumulation in response to pathogen infection. Further, we isolated a mitogen-activated protein (MAP) kinase substrate gene, BnMKS1, and found that not only can BnWRKY33 interact with BnMKS1, which can also interact with BnMPK4, using the yeast two-hybrid assay, consistent with their collective nuclear localization, but also BnWRKY33, BnMKS1 and BnMPK4 are substantially and synergistically expressed in response to S. sclerotiorum infection. In contrast, the three genes showed differential expression in response to phytohormone treatments. Together, these results suggest that BnWRKY33 plays an important role in B. napus defence to S. sclerotiorum, which is most probably associated with the activation of the salicylic acid (SA)- and jasmonic acid (JA)-mediated defence response and inhibition of H2 O2 accumulation, and we propose a potential mechanism in which BnMPK4-BnMKS1-BnWRKY33 exist in a nuclear localized complex to regulate resistance to S. sclerotiorum in oilseed rape. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  11. Effect of the cBN content and sintering temperature on the transverse rupture strength and hardness of cBn/diamond cutting tools

    Directory of Open Access Journals (Sweden)

    Kır Durmuş

    2012-01-01

    Full Text Available The aim of this work was to investigate the effect of cBN content and sintering temperature on the transverse rupture strength (TRS of cBN/diamond cutting tools produced by hot pressing. The segments containing different cBN content were manufactured under 35 MPa pressure at 600, 650 and 700°C with a 3 minutes sintering time. The TRS of segments were determined using three-point bending test. Microstructure and phase composition of fracture surface of segments were determined by scanning electron microscopy (SEM, and X-ray diffraction (XRD analysis. The obtained results show that the TRS of the segments with cBN were higher than that of the segments with diamond.

  12. Cubic and hexagonal boron-nitride (c-BN/h-BN) thin films deposited in situ by r.f. magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.M.; Zambrano, G.; Baca, E.; Moran, O.; Prieto, P. [Departamento de Fisica, Universidad del Valle, A.A. 25360 Cali (Colombia); Bejarano, G. [Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia)

    2005-07-01

    Cubic boron-nitride (c-BN)/hexagonal boron nitride (h-BN) thin films were grown in situ on (100) oriented silicon substrates by r.f. (13.56 MHz) magnetron sputtering technique. In order to obtain the highest fraction of the c-BN phase, a negative d.c bias voltage, varying from 0 to -200 V was applied to the substrate during deposition. Another set of boron nitride thin films was deposited in situ on (100) oriented silicon substrates under r.f. bias voltage. The substrate holder was biased from 0 to -350 V by connecting such to an auxiliary r.f. generator (operated at 13.56 MHz). Films were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) and Atomic Force Microscope (AFM). Well-defined peaks at 787 cm{sup -1}, 1100 cm{sup -1} and 1387 cm{sup -1}, corresponding to the 2{sub Au} (out-plane bending of B-N-B bond) h-BN vibration mode, the F2 (stretching) c-BN Transversal Optical (TO) mode and the E{sub 1u} (in-plane stretching of B-N bond) vibration mode of the h-BN, respectively, were observed in the FTIR spectra. A maximal fraction of the c-BN phase close to 85% was obtained under a bias voltage of -150 V at substrate temperature of 300 C and a total pressure of 4 x 10{sup -2} mbar. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. A comparative DFT study on the interaction of cathinone drug with BN nanotubes, nanocages, and nanosheets

    Science.gov (United States)

    Nejati, Kamellia; Hosseinian, Akram; Vessally, Esmail; Bekhradnia, Ahmadreza; Edjlali, Ladan

    2017-11-01

    Cathinone is an organic stimulant which is classified as psychoactive drug and its abuse has been linked to many deaths worldwide. Here, we studied the electronic sensitivity of a BN cage, a zigzag (6, 0) BN nanotube, and a BN nanosheet toward cathinone using density functional theory calculations. The B3LYP-D functional predicts that the order of magnitude of electrical conductivity of BN nanostructures is as follows tube > sheet > cage. The cathinone drug prefers to be adsorbed on the BN nanostructures via its sbnd NH2 group rather than O-head with adsorption energy about -16.1, -14.0 and -5.0 kcal/mol for cage, tube, and sheet, respectively. Our results indicate that by increasing the p-character of the hybridization of the adsorbing B atom in the BN nanostructures, the interaction is strengthened. Based on the density of states analysis, it was demonstrated that the electrical conductivity of the BN nanostructures is decreased by the drug adsorption, indicating that they can be used in the cathinone sensors. The order of magnitude of the sensitivity is as follows: SCage > STube > SSheet. This trend corresponds to the decrease of the structural curvature in the BN nanostructures. Finally, a short recovery time of about 0.54 s, 0.02 s and 4.4 ns is predicted for cage, tube and sheet, respectively, at 298 K.

  14. van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices

    Science.gov (United States)

    Avsar, Ahmet; Tan, Jun Y.; Luo, Xin; Khoo, Khoong Hong; Yeo, Yuting; Watanabe, Kenji; Taniguchi, Takashi; Quek, Su Ying; Özyilmaz, Barbaros

    2017-09-01

    Due to the chemical inertness of 2D hexagonal-Boron Nitride (h-BN), few atomic-layer h-BN is often used to encapsulate air-sensitive 2D crystals such as Black Phosphorus (BP). However, the effects of h-BN on Schottky barrier height, doping and contact resistance are not well known. Here, we investigate these effects by fabricating h-BN encapsulated BP transistors with cobalt (Co) contacts. In sharp contrast to directly Co contacted p-type BP devices, we observe strong n-type conduction upon insertion of the h-BN at the Co/BP interface. First principles calculations show that this difference arises from the much larger interface dipole at the Co/h-BN interface compared to the Co/BP interface, which reduces the work function of the Co/h-BN contact. The Co/h-BN contacts exhibit low contact resistances (~ 4.5 k-ohm), and are Schottky barrier free. This allows us to probe high electron mobilities (4,200 cm2/Vs) and observe insulator-metal transitions even under two-terminal measurement geometry.

  15. Significant stress reduction of cBN layers upon ion irradiation at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Weidner, Stefan; Geburt, Sebastian; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena (Germany); Ye, Jian; Ulrich, Sven [Institut fuer Materialforschung, Forschungszentrum Karlsruhe (Germany)

    2011-07-01

    Cubic boron nitride (cBN) is the hardest materials beneath diamond and exceeds the properties in terms of chemical resistivity, making it a promising candidate for ultra-hard coatings in extreme environments. Due to the ion assisted growth process, the cBN layers suffer from an intrinsic stress, which limits the layer thickness and therefore possible industrial applications. To investigate new approaches for the synthesis of low stress cBN layers, we applied ion irradiation with various ion species (O,Ne,Kr) and at different temperatures between 300 to 600 K to cBN:O layers. The intrinsic stress and the cBN content were monitored by profilometer and FTIR after each implantation step. As expected, ion irradiation at room temperature leads to a stress reduction with constant cBN content upon an ion induced damage up to 0.5 dpa, but a severe damage is introduced to the layer above this value resulting into a phase transition to hBN. However, irradiation at elevated temperatures results in a significant stress reduction without decrease of the cBN quality even up to 4.3 dpa.

  16. Data of evolutionary structure change: 1BN7A-2PSEA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1BN7A-2PSEA 1BN7 2PSE A A ------------IGTGFPFDPHYVEVLGERMHYVDVGPRDGTPVLFLHGNPTSSYL...2PSE A 2PSEA ELLNLPKKIIF ...2PSE A 2PSEA PFKEKGEVRRP ...2PSE A 2PSEA PLVKGGKPDVV ...2PSE A 2PSEA LRASDDLPKLF

  17. Data of evolutionary structure change: 1BN6A-2PSEA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1BN6A-2PSEA 1BN6 2PSE A A ------------IGTGFPFDPHYVEVLGERMHYVDVGPRDGTPVLFLHGNPTSSYL...2PSE A 2PSEA ELLNLPKKIIF ...2PSE A 2PSEA FKEKGEVRRPT ...2PSE A 2PSEA PLVKGGKPDVV ...2PSE A 2PSEA YLRASDDLPKL

  18. BnWRI1 coordinates fatty acid biosynthesis and photosynthesis pathways during oil accumulation in rapeseed.

    Science.gov (United States)

    Wu, Xue-Long; Liu, Zhi-Hong; Hu, Zhang-Hua; Huang, Rui-Zhi

    2014-06-01

    Photosynthesis in "green" seeds, such as rapeseed, soybean, and Arabidopsis, plays a substantial role in the improved efficiency of oil accumulation. However, the molecular mechanism underpinning the coordinated expression of fatty acid (FA) biosynthesis- and photosynthesis-related genes in such developing seeds remains to be elucidated. Here, we found that seed-specific overexpression of BnWRI1, a WRI1 homolog from rapeseed (Brassica napus cv. ZGY2), results in enhanced chlorophyll content in developing seeds and increased oil content and seed mass in matured seeds. BnWRI1 was co-expressed with BnBCCP and BnCAB, two marker genes of FA biosynthesis and photosynthesis during seed development, respectively. Overexpression of BnWRI1 increased expression of both marker genes. Further, the nuclear-localized BnWRI1 protein was found to act as a transcription activator. It could bind to the GT1-element and/or GCC-box, which are widespread in the upstream regions of genes involved in FA biosynthesis and photosynthesis pathways. Accordingly, BnWRI1 could interact with promoters of BCCP2 and LHB1B2 in vivo. These results suggested that BnWRI1 may coordinate FA biosynthesis and photosynthesis pathways in developing seeds via directly stimulating expression of GT1-element and/or GCC-box containing genes. © 2014 Institute of Botany, Chinese Academy of Sciences.

  19. Nanoindentation of ultra-hard cBN films: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Cheng [College of Aerospace Engineering, Chongqing University, Chongqing 400044 (China); Peng, Xianghe, E-mail: xhpeng@cqu.edu.cn [College of Aerospace Engineering, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400044 (China); Fu, Tao, E-mail: futaocqu@163.com [College of Aerospace Engineering, Chongqing University, Chongqing 400044 (China); Zhao, Yinbo; Feng, Chao; Lin, Zijun [College of Aerospace Engineering, Chongqing University, Chongqing 400044 (China); Li, Qibin [College of Aerospace Engineering, Chongqing University, Chongqing 400044 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400044 (China)

    2017-01-15

    Highlights: • We optimize tersoff potential to better simulate the BN. • We perform respectively the nanoindentations on the (001) and (111) surface of cBN. • The main slip system of cBN under nanoindentation is {111}<110>. • Temperature has a significant effect on the mechanical properties of cBN. - Abstract: Cubic Boron nitride (cBN) exhibits excellent mechanical properties including high strength, hardness and thermal resistance, etc. We optimized the parameters in the Tersoff interatomic potential for cBN based on its cohesive energy, lattice parameter, elastic constants, surface energy and stacking fault energy. We performed with molecular dynamics (MD) simulations the nanoindentation on the (001) and (111) surface of monocrystalline cBN thin films to study the deformation mechanisms and the effects of temperature and substrate orientation. It was found that during the indentation plastic deformation is mainly stress-induced slips of dislocations along {111}<110> orientations. It was also found that the hardness of cBN depends strongly on temperature, and the capability of plastic deformation is enhanced with the increase of temperature.

  20. One-pot synthesis of h-BN fullerenes usinsg a graphene oxide template

    Science.gov (United States)

    Kim, Sang Sub; Khai, Tran Van; Kwon, Yong Jung; Katoch, Akash; Wu, Ping; Kim, Hyoun Woo

    2015-09-01

    Hexagonal-boron nitride ( h-BN) fullerenes were synthesized from a graphene oxide (GO) template by simultaneously heating the GO and B2O3 in the presence of NH3 gas. Transmission electron microscopy (TEM) observations revealed that a considerable amount of product had a fullerene-like nanostructure. Typical BN fullerenes have a polyhedral shape, being hollow nanocages. Lattice-resolved TEM and X-ray diffraction consistently demonstrated the formation of h-BN fullerenes. The FTIR spectrum exhibited absorption bands at approximately 800 and 1378 cm-1, which were related to the h-BN structure. The Raman spectra exhibited peaks at 1368 and 1399 cm-1, which can be related to BN sheets and BN fullerenes, respectively. The photoluminescence spectrum of the h-BN fullerenes taken at 8 K exhibited intense white-light emission. To reveal the origin of the broad emission band, which could be a superimposition of several peaks, we used a deconvolution procedure based on Gaussian functions. We proposed a growth mechanism of the h-BN fullerenes and verified it with a thermodynamic calculation. This work provides a cost-effective approach to synthesize fullerene-type boron nitride on a production scale.

  1. Microstructure and mechanical properties of SiO2-BN ceramic and Invar alloy joints brazed with Ag–Cu–Ti+TiH2+BN composite filler

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2016-03-01

    Full Text Available Ag–Cu–Ti + TiH2+BN composite filler was prepared to braze SiO2-BN ceramic and Invar alloy. The interfacial microstructure, mechanical properties, and residual stress distribution of the brazed joints were investigated. The results show that a wave-like Fe2Ti–Ni3Ti structure appears in the Invar substrate and a thin TiN–TiB2 reaction layer forms adjacent to the SiO2-BN ceramic. The added BN particles react with Ti to form TiN–TiB fine-particles, which is beneficial to refine the microstructure of the brazing seam and to greatly inhibit the brittle compounds formation. The interfacial microstructure at various brazing temperatures was analyzed, and the mechanism for the interfacial reactions responsible for the bonding was proposed. The maximum shear strength of the joints brazed with the composite filler at 880 °C for 10 min is 39 MPa, which is 30% greater than that brazed with Ag–Cu–Ti alloy. The improvement of the joint strength is attributed to the variation of joint microstructure and the reduction of tensile stresses induced in the SiO2-BN ceramic. The finite element analysis indicates that the peak tensile stress decreases from 230 to 142 MPa due to the addition of BN particles in the ceramic.

  2. Incorporation of small BN domains in graphene during CVD using methane, boric acid and nitrogen gas.

    Science.gov (United States)

    Bepete, George; Voiry, Damien; Chhowalla, Manish; Chiguvare, Zivayi; Coville, Neil J

    2013-07-21

    Chemical doping of graphene with small boron nitride (BN) domains has been shown to be an effective way of permanently modulating the electronic properties in graphene. Herein we show a facile method of growing large area graphene doped with small BN domains on copper foils using a single step CVD route with methane, boric acid powder and nitrogen gas as the carbon, boron and nitrogen sources respectively. This facile and safe process avoids the use of boranes and ammonia. Optical microscopy confirmed that continuous films were grown and Raman spectroscopy confirmed changes in the electronic structure of the grown BN doped graphene. Using XPS studies we find that both B and N can be substituted into the graphene structure in the form of small BN domains to give a B-N-C system. A novel structure for the BN doped graphene is proposed.

  3. Characterization of Wheel Surface Topography in cBN Grinding

    Science.gov (United States)

    Fujimoto, Masakazu; Ichida, Yoshio; Sato, Ryunosuke; Morimoto, Yoshitaka

    The wheel surface topography in the grinding process with vitrified cBN wheels has been investigated on the basis of 3-dimensional analysis using a multi-probe SEM, and the relationships between these results and the grinding characteristic parameters have been discussed. Moreover, the change of the wheel surface profile in the grinding process has been evaluated using fractal analysis. There are two regions: an initial wear region and a steady-state wear region, in the grinding process. In the initial wear region, a rapid decrease of grinding force and a rapid increase of wheel wear occur with increasing stock removal. In the steady-state wear region, the micro self-sharpening phenomenon owing to the micro fracture as well as the attritious wear of cutting edge occurs. The change in fractal dimension of the wheel surface is closely related to the change of grinding force dominated by the wear behavior of grain cutting edges.

  4. High-Pressure Design of Advanced BN-Based Materials

    Directory of Open Access Journals (Sweden)

    Oleksandr O. Kurakevych

    2016-10-01

    Full Text Available The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN with hardness comparable to diamond, and superhard boron subnitride B13N2. Thermodynamic and kinetic aspects of high-pressure synthesis are described based on the data obtained by in situ and ex situ methods. Mechanical and thermal properties (hardness, thermoelastic equations of state, etc. are discussed. New synthetic perspectives, combining both soft chemistry and extreme pressure–temperature conditions are considered.

  5. Naphthalene degradation and biosurfactant activity by Bacillus cereus 28BN

    Energy Technology Data Exchange (ETDEWEB)

    Tuleva, B.; Christova, N. [Inst. of Microbiology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Jordanov, B.; Nikolova-Damyanova, B. [Inst. of Organic Chemistry, Sofia (Bulgaria); Petrov, P. [National Center of Infectious and Parasitic Diseases, Sofia (Bulgaria)

    2005-08-01

    Biosurfactant activity and naphthalene degradation by a new strain identified as Bacillus cereus 28BN were studied. The strain grew well and produced effective biosurfactants in the presence of n-alkanes, naphthalene, crude oil and vegetable oils. The biosurfactants were detected by the surface tension lowering of the medium, thin layer chromatography and infrared spectra analysis. With (2%) naphthalene as the sole carbon source, high levels of rhamnolipids at a concentration of 2.3 g l{sup -1} were determined in the stationary growth. After 20 d of incubation 72 {+-} 4% of the initial naphthalene was degraded. This is the first report for a Bacillus cereus rhamnolipid producing strain that utilized naphthalene under aerobic conditions. The strain looks promising for application in environmental technologies. (orig.)

  6. BN-C Hybrid Nanoribbons as Gas Sensors

    Science.gov (United States)

    Darvishi Gilan, Mahdi; Chegel, Raad

    2018-02-01

    The effects of carbon monoxide (CO) and ammonia (NH3) molecules adsorption on the various composites of boron nitride and graphene BN-C hybrid nanoribbons are investigated using the non-equilibrium Green's function (NEGF) technique based on density functional theory (DFT). The effects of adsorption with possible random configurations on the average of the density of states (DOS), transmission coefficient, and the current-voltage ( I- V) characteristics are calculated. The results indicate that, by embedding armchair graphene nanoribbon (AGNR) with boron nitride nanoribbon (BNNR), the various electronic properties can be observed after gas molecule adsorption. The electronic structure and gap of hybrids system is modified due to gas adsorption, and the systems act like the n-type semiconductor by NH3 molecule adsorption. The hybrid structures due to their tunable band gap are better candidates for gas detecting compared to the pristine BNNRs and AGNRs.

  7. Low frequency Raman spectroscopy of few-atomic-layer thick hBN crystals

    Science.gov (United States)

    Stenger, I.; Schué, L.; Boukhicha, M.; Berini, B.; Plaçais, B.; Loiseau, A.; Barjon, J.

    2017-09-01

    Hexagonal boron nitride (hBN) has recently gained a strong interest as a strategic component in engineering van der Waals heterostructures built with 2D crystals such as graphene. This work reports micro-Raman measurements on hBN flakes made of a few atomic layers, prepared by mechanical exfoliation. The temperature dependence of the Raman scattering in hBN is investigated first such as to define appropriate measurements conditions suitable for thin layers avoiding undesirable heating induced effects. We further focus on the low frequency Raman mode corresponding to the rigid shearing oscillation between adjacent layers, found to be equal to 52.5 cm-1 in bulk hBN. For hBN sheets with thicknesses below typically 4 nm, the frequency of this mode presents discrete values, which are found to decrease down to 46.0(5) cm-1 for a three-layer hBN, in good agreement with the linear-chain model. This makes Raman spectroscopy a relevant tool to quantitatively determine in a non destructive way the number of layers in ultra thin hBN sheets, below 8 L, prior to their integration in van der Waals heterostructures.

  8. Pnma-BN: Another Boron Nitride Polymorph with Interesting Physical Properties

    Directory of Open Access Journals (Sweden)

    Zhenyang Ma

    2016-12-01

    Full Text Available Structural, mechanical, electronic properties, and stability of boron nitride (BN in Pnma structure were studied using first-principles calculations by Cambridge Serial Total Energy Package (CASTEP plane-wave code, and the calculations were performed with the local density approximation and generalized gradient approximation in the form of Perdew–Burke–Ernzerhof. This BN, called Pnma-BN, contains four boron atoms and four nitrogen atoms buckled through sp3-hybridized bonds in an orthorhombic symmetry unit cell with Space group of Pnma. Pnma-BN is energetically stable, mechanically stable, and dynamically stable at ambient pressure and high pressure. The calculated Pugh ratio and Poisson’s ratio revealed that Pnma-BN is brittle, and Pnma-BN is found to turn brittle to ductile (~94 GPa in this pressure range. It shows a higher mechanical anisotropy in Poisson’s ratio, shear modulus, Young’s modulus, and the universal elastic anisotropy index AU. Band structure calculations indicate that Pnma-BN is an insulator with indirect band gap of 7.18 eV. The most extraordinary thing is that the band gap increases first and then decreases with the increase of pressure from 0 to 60 GPa, and from 60 to 100 GPa, the band gap increases first and then decreases again.

  9. Optoelectronic properties of higher acenes, their BN analogue and substituted derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Armaković, Stevan, E-mail: stevan.armakovic@df.uns.ac.rs [University of Novi Sad, Faculty of Sciences, Department of Physics, Trg Dositeja Obradovića 4, 21000, Novi Sad (Serbia); Armaković, Sanja J. [University of Novi Sad, Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg Dositeja Obradovića 3, 21000, Novi Sad (Serbia); Holodkov, Vladimir [Educons University, Faculty of Sport and Tourism - TIMS, Radnička 30a, 21000, Novi Sad (Serbia); Pelemiš, Svetlana [University of East Sarajevo, Faculty of Technology, Karakaj bb, 75400, Zvornik, Republic of Srpska, Bosnia and Herzegovina (Bosnia and Herzegovina)

    2016-02-15

    We have investigated optoelectronic properties of higher acenes: pentacene, hexacene, heptacene, octacene, nonacene, decacene and their boron-nitride (BN) analogues, within the framework of density functional theory (DFT). We have also investigated the optoelectronic properties of acenes modified by BN substitution. Calculated optoelectronic properties encompasses: oxidation and reduction potentials, electron and hole reorganization energies and energy difference between excited first singlet and triplet states ΔE(S{sub 1}−T{sub 1}). Oxidation and reduction potentials indicate significantly better stability of BN analogues, comparing with their all-carbon relatives. Although higher acenes possess lower electron and hole reorganization energies, with both best values much lower than 0.1 eV, their BN analogues also have competitive values of reorganization energies, especially for holes for which reorganization energy is also lower than 0.1 eV. On the other hand ΔE(S{sub 1}−T{sub 1}) is much better for BN analogues, having values that indicate that BN analogues are possible applicable for thermally activated delayed fluorescence. - Highlights: • Optoelectronic properties of structures based on higher acenes have been investigated. • Oxidation and reduction potentials together with reorganization energies are calculated. • TADF is analyzed through calculation of ΔE(S{sub 1}−T{sub 1}), which is much better for BN analogues. • Reorganization energies of acenes improve with the increase of number of benzene rings.

  10. Controlling the electronic properties of the graphene nanoflakes by BN impurities

    Science.gov (United States)

    Mohammed, Mohammed H.

    2018-01-01

    Electronic properties of the graphene nanoflakes (GNFs) can be controlled by using chemical doping method. First-principle of the density functional theory (DFT) method, which is implemented in the Gaussian 09W program are used to investigate the electronic properties, such as electronic band gap, DOS, total energy, dipole moment, HOMO, and LOMO energies of the GNFs with and without various concentrations of the BN impurities in various sites. There are very significant results. My founding results show that these properties of the GNFs depend on the concentrations of BN impurities and the geometrical pattern of the BN impurities in the GNFs. By increasing the distance between these impurities, the electronic band gap and the shape of the DOS are reduced and altered, respectively. So, the results offer that the electronic band gap value depends on the concentrations of BN impurities and sites of these impurities in the GNFs. The electronic dipole moments value is increased by increased the concentrations of the BN impurities. All structures became more stable due to the total energy is increased, excepted B, BN and B2N impurities, which is reduced and make GNFs structure unstable. Then, GNFs can be used in various applications because the electronic properties of the GNFs are controlled and modified with BN impurities.

  11. Growth of two-dimensional materials on non-catalytic substrates: h-BN/Au(111)

    Science.gov (United States)

    Camilli, L.; Sutter, E.; Sutter, P.

    2014-09-01

    The growth of two-dimensional (2D) materials is a topic of very high scientific and technological interest. While chemical vapour deposition on catalytic metals has become a well developed approach for the growth of graphene and hexagonal boron nitride (BN), very few alternative approaches for synthesis on non-reactive supports have been explored so far. Here we report the growth of BN on gold, using magnetron sputtering of B in N2/Ar atmosphere, a scalable method using only non-toxic reagents. Scanning tunnelling microscopy at low coverage shows primarily triangular monolayer BN islands exhibiting two ‘magic’ orientations on the Au(111) surface. Such rotational alignment of BN on Au(111) is surprising, given the expected weak binding and the high lattice mismatch (˜14%) between BN and Au. Our observations are consistent with a strong coupling between the edges of BN flakes and the substrate, which leads to the selection of BN orientations that maximize the orbital overlap between edge atoms and Au surface atoms. Diverse flake morphologies resembling the shape of butterflies, six-apex stars and diamonds, implying alternating B- and N- terminated edges, are observed as well. Our results provide insight into the growth mechanisms of 2D materials on weakly interacting and chemically inert substrates, and provide the basis for integrating other 2D materials with atomically precise graphene nanostructures synthesized from molecular precursors on Au.

  12. Alternating current electrophoretic deposition of HA and hBN nanoparticles on Ti substrate

    OpenAIRE

    Geçgin, Merve; AY, Nuran; Göncü, Yapıncak

    2017-01-01

    Hydroxyapatite (HA) and hexagonal boron nitride(hBN) are biocompatible materials. In this study, nano HA and nano hBN were usedfor coatings of titanium (Ti) substrate. The nanoparticles were deposited on Ti substrates by alternating current electrophoretic deposition (AC-EPD). Suspensions were consist of nano HA and also comprised of the various amount of nano hBN (0.0-2.0-5.0-10.0 and 25.0 wt. % by the percentage of hydroxyapatite). The coated samples were heat treated at 800C in Aratmospher...

  13. Sensitivity of BN nano-cages to caffeine and nicotine molecules

    Science.gov (United States)

    Soltani, Alireza; Baei, Mohammad T.; Tazikeh Lemeski, E.; Shahini, Malihe

    2014-12-01

    Adsorption of caffeine and nicotine molecules over B12N12 and B16N16 nano-cages were investigated by using first-principles calculations to define whether BN nano-cages are applicable for filtering or sensing caffeine and nicotine molecules. The chemisorption energy of nicotine molecule on BN nano-cages is very stronger than caffeine molecule. Upon the adsorption of caffeine and nicotine molecules, the electronic properties of the BN nano-cages can be significantly changed, being too much sensitized on the caffeine and nicotine adsorptions.

  14. Sepsis Patient Detection and Monitor Based on Auto-BN.

    Science.gov (United States)

    Jiang, Yu; Sha, Lui; Rahmaniheris, Maryam; Wan, Binhua; Hosseini, Mohammad; Tan, Pengliu; Berlin, Richard B

    2016-04-01

    Sepsis is a life-threatening condition caused by an inappropriate immune response to infection, and is a leading cause of elderly death globally. Early recognition of patients and timely antibiotic therapy based on guidelines improve survival rate. Unfortunately, for those patients, it is often detected late because it is too expensive and impractical to perform frequent monitoring for all the elderly. In this paper, we present a risk driven sepsis screening and monitoring framework to shorten the time of onset detection without frequent monitoring of all the elderly. Within this framework, the sepsis ultimate risk of onset probability and mortality is calculated based on a novel temporal probabilistic model named Auto-BN, which consists of time dependent state, state dependent property, and state dependent inference structures. Then, different stages of a patient are encoded into different states, monitoring frequency is encoded into the state dependent property, and screening content is encoded into different state dependent inference structures. In this way, the screening and monitoring frequency and content can be automatically adjusted when encoding the sepsis ultimate risk into the guard of state transition. This allows for flexible manipulation of the tradeoff between screening accuracy and frequency. We evaluate its effectiveness through empirical study, and incorporate it into existing medical guidance system to improve medical healthcare.

  15. Methoxylation of Singly Bonded 1,4-1',4'-BnC60-C60Bn Dimer: Preferential Formation of 1,4-C60 Adduct with Sterically Less Demanding Addends and Stability Difference between 1,2- and 1,4-OMe(Bn)C60.

    Science.gov (United States)

    He, Fa-Gui; Li, Zong-Jun; Gao, Xiang

    2016-08-05

    Methoxylation of the singly bonded 1,4-1',4'-BnC60-C60Bn dimer afforded 1,4-OMe(Bn)C60, a 1,4-C60 adduct with sterically less demanding addends, as the major adduct. The situation was different from that of direct functionalization of C60, where 1,2-OMe(Bn)C60 was obtained as the major product. The reaction was studied with in situ vis-NIR spectroscopy and computational calculations to obtain a better understanding of this unusual regioselectivity. The stability difference between 1,2- and 1,4-OMe(Bn)C60 was studied.

  16. Evaluating the microstructure and mechanical performance of sputtered TiAlBN nanocomposite coating

    Science.gov (United States)

    Das, Pritam; Anwar, Shahid; Anwar, Sharmistha

    2017-05-01

    We report here the microstructural and mechanical properties of nanocrystalline (nc) Titanium Aluminium Nitride (TiAlN) embedded in nanocrystalline Boron Nitride (BN) nanocomposite films. The coatings were deposited on Si substrate using reactive magnetron co-sputtering by varying BN power. Coatings were characterized by using grazing incident X-ray diffraction (GIXRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and nanoindentation. GIXRD showed the formation of cubic Ti3AlN and hexagonal BN phase in the coating. Variation in structure and target power of BN influence the mechanical property of the coating. Mechanical property increases with power up to 100W, then decrease with further increase in power.

  17. h-BN-layer-induced chiral decomposition in the electronic properties of multilayer graphene

    Science.gov (United States)

    Zasada, I.; Maślanka, P.; Molenda, A.; Łuczak, K.

    2018-02-01

    We discuss the chiral decomposition of non-symmetric stacking structures. It is shown that the low-energy electronic structure of a Bernal stacked graphene multilayer deposited on h-BN consists of chiral pseudospin doublets. N-layer graphene stacks on the h-BN layer have N/2 effective bilayer graphene systems and one effective h-BN layer if N is even or (N-1)/2 effective graphene bilayers plus one graphene monolayer modified by an h-BN layer if N is odd. We present the decomposition procedure and derive the recurrence relations for the effective parameters characterizing the chiral subsystems. In this case, the effective parameters consist of interlayer couplings and on-site potentials in contrast to pure graphene multilayer systems where only interlayer couplings are modified. We apply this procedure to discuss the Klein tunnelling phenomena and quantitatively compare the results with pure graphene multilayer systems.

  18. Structural analysis of graphene and h-BN: A molecular dynamics approach

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Siby; Ajith, K. M., E-mail: ajith@nitk.ac.in [Computational Physics Lab, Department of Physics, National Institute of technology Karnataka, Surathkal PO: Srinivasnagar, Mangalore, India - 575025 (India); Valsakumar, M. C. [Department of physics, Indian Institute of Technology Palakkad, Ahalia Campus, Kozhipara, Palakkad, Kerala, India - 678557 (India)

    2016-05-06

    Classical molecular dynamics simulation is employed to analyze pair correlations in graphene and h-BN at various temperatures to explore the integrity of their respective structures. As the temperature increases, the height fluctuations in the out-of-plane direction of both graphene and h-BN are found to increase. The positional spread of atoms also increases with temperature. Thus the amplitude of the peak positions in the radial distribution function (RDF) decreases with temperature. It is found that FWHM of peaks in the RDF of h-BN is smaller as compared to those of graphene which implies that the structure of h-BN is more robust as compared to that of graphene with respect to their respective empirical potential.

  19. Ultrafast relaxation of hot phonons in graphene-hBN heterostructures

    Directory of Open Access Journals (Sweden)

    Dheeraj Golla

    2017-05-01

    Full Text Available Fast carrier cooling is important for high power graphene based devices. Strongly coupled optical phonons play a major role in the relaxation of photoexcited carriers in graphene. Heterostructures of graphene and hexagonal boron nitride (hBN have shown exceptional mobility and high saturation current, which makes them ideal for applications, but the effect of the hBN substrate on carrier cooling mechanisms is not understood. We track the cooling of hot photo-excited carriers in graphene-hBN heterostructures using ultrafast pump-probe spectroscopy. We find that the carriers cool down four times faster in the case of graphene on hBN than on a silicon oxide substrate thus overcoming the hot phonon bottleneck that plagues cooling in graphene devices.

  20. Enhancing the mechanical properties of BN nanosheet-polymer composites by uniaxial drawing.

    Science.gov (United States)

    Jan, Rahim; May, Peter; Bell, Alan P; Habib, Amir; Khan, Umar; Coleman, Jonathan N

    2014-05-07

    We have used liquid exfoliation of hexagonal Boron-Nitride (BN) to prepare composites of BN nanosheets of three different sizes in polyvinylchloride matrices. These composites show low levels of reinforcement, consistent with poor alignment of the nanosheets as-described by a modified version of Halpin-Tsai theory. However, drawing of the composites to 300% strain results in a considerable increase in mechanical properties with the maximum composite modulus and strength both ∼×3 higher than that of the pristine polymer. In addition, the rate of increase of modulus with BN volume fraction was up to 3-fold larger than for the unstrained composites. This is higher than can be explained by drawing-induced alignment using Halpin-Tsai theory. However, the data was consistent with a combination of alignment and strain-induced de-aggregation of BN multilayers.

  1. Selective-area heteroepitaxial growth of h-BN micropatterns on graphene layers

    Science.gov (United States)

    Yun, Jiyoung; Oh, Hongseok; Jo, Janghyun; Lee, Hyun Hwi; Kim, Miyoung; Yi, Gyu-Chul

    2018-01-01

    We report the selective-area heteroepitaxial growth of hexagonal boron nitride (h-BN) on graphene layers using catalyst-free chemical vapor deposition. For both catalyst-free and selective-area growth, exfoliated graphene layers were irradiated with a focused ion beam to generate nucleation sites on the inert graphene surface. A high-quality, ultrathin h-BN micropattern array was selectively grown only on the patterned region of graphene using borazine, ammonia, and nitrogen without any metal catalyst. The crystal structure and microstructural properties of h-BN grown on graphene were investigated using synchrotron radiation x-ray diffraction and transmission electron microscopy, respectively. The catalyst-free growth mechanism and heteroepitaxial relationship between h-BN and graphene layers are discussed.

  2. Calculation of the octanol-water partition coefficient of armchair polyhex BN nanotubes

    Science.gov (United States)

    Mohammadinasab, E.; Pérez-Sánchez, H.; Goodarzi, M.

    2017-12-01

    A predictive model for determination partition coefficient (log P) of armchair polyhex BN nanotubes by using simple descriptors was built. The relationship between the octanol-water log P and quantum chemical descriptors, electric moments, and topological indices of some armchair polyhex BN nanotubes with various lengths and fixed circumference are represented. Based on density functional theory electric moments and physico-chemical properties of those nanotubes are calculated.

  3. BnNAC485 is involved in abiotic stress responses and flowering time in Brassica napus.

    Science.gov (United States)

    Ying, Lu; Chen, Haiying; Cai, Weiming

    2014-06-01

    NAC domain proteins are plant-specific transcription factors that play important roles in plant growth and development. In this present study, we isolated BnNAC485 from Brassica napus L. (cv. HuYou15) and found that it showed high homology (84% at the amino acid level) with a NAC protein called AtRD26/ANAC072. BnNAC485 was specifically expressed in cotyledons and leaves of young seedlings, and expression was induced by abiotic stress and abscisic acid (ABA) treatment. The BnNAC485 protein localized to the nucleus. Over-expression of BnNAC485 enhanced tolerance to abiotic stress compared with wild-type plants in both B. napus and Arabidopsis thaliana. Furthermore, under exogenous ABA stress, BnNAC485 over-expression lines showed hypersensitivity to this treatment compared with wild-type B. napus and A. thaliana plants. Moreover, exogenous ABA treatment enhanced stomatal closing in B. napus plants over-expressing BnNAC485. Real-time RT-PCR assays showed that some abiotic- or ABA-responsive genes were up-regulated in A. thaliana plants over-expressing BnNAC485. Additionally, the transgenic lines flowered earlier than the wild-type B. napus and A. thaliana plants and the expression patterns of certain circadian clock genes were found to have changed. These results suggest that BnNAC485 acts in response to abiotic stress in plants via an ABA-mediated pathway and this gene can also alter plant flowering time. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Band gap tunning in BN-doped graphene systems with high carrier mobility

    KAUST Repository

    Kaloni, T. P.

    2014-02-17

    Using density functional theory, we present a comparative study of the electronic properties of BN-doped graphene monolayer, bilayer, trilayer, and multilayer systems. In addition, we address a superlattice of pristine and BN-doped graphene. Five doping levels between 12.5% and 75% are considered, for which we obtain band gaps from 0.02 eV to 2.43 eV. We demonstrate a low effective mass of the charge carriers.

  5. Negligible environmental sensitivity of graphene in a hexagonal boron nitride/graphene/h-BN sandwich structure.

    Science.gov (United States)

    Wang, Lei; Chen, Zheyuan; Dean, Cory R; Taniguchi, Takashi; Watanabe, Kenji; Brus, Louis E; Hone, James

    2012-10-23

    Using Raman spectroscopy, we study the environmental sensitivity of mechanically exfoliated and electrically floating single-layer graphene transferred onto a hexagonal boron nitride (h-BN) substrate, in comparison with graphene deposited on a SiO(2) substrate. In order to understand and isolate the substrate effect on graphene electrical properties, we model and correct for Raman optical interference in the substrates. As-deposited and unannealed graphene shows a large I(2D)/I(G) ratio on both substrates, indicating extremely high quality, close to that of graphene suspended in vacuum. Thermal annealing strongly activates subsequent environmental sensitivity on the SiO(2) substrate; such activation is reduced but not eliminated on the h-BN substrate. In contrast, in a h-BN/graphene/h-BN sandwich structure, with graphene protected on both sides, graphene remains pristine despite thermal processing. Raman data provide a deeper understanding of the previously observed improved graphene electrical conductivity on h-BN substrates. In the sandwich structure, the graphene 2D Raman feature has a higher frequency and narrower line width than in pristine suspended graphene, implying that the local h-BN environment modestly yet measurably changes graphene electron and phonon dispersions.

  6. Theoretical study on critical thickness of heteroepitaxial h-BN on hexagonal crystals

    Science.gov (United States)

    Yu, Jiadong; Wang, Lai; Hao, Zhibiao; Luo, Yi; Sun, Changzheng; Han, Yanjun; Xiong, Bing; Wang, Jian; Li, Hongtao

    2017-06-01

    Hexagonal crystals are suitable underlayer candidates for hexagonal boron nitride (h-BN) heteroepitaxy due to their similar in-plane atomic arrangement. When the thickness of h-BN is beyond a critical value, its accumulated stress resulting from the lattice mismatch can be relaxed by generating dislocation or changing into three-dimensional growth. Here we calculate the evolution of h-BN critical thickness with the growth temperature when it is grown on various frequently-used hexagonal crystals for both cases. The results show that in order to minimize the lattice mismatch, a low growth temperature is preferred when grown on GaN or Si(1 1 1) while on the contrary when grown on 6H-SiC or α-Al2O3. Besides, AlN is the most unique underlayer as its lattice mismatch with h-BN is relatively small (100 nm) growth. Moreover, large area of two-dimensional thin h-BN (5-15 nm) layer can be obtained on GaN, 6H-SiC, Si(1 1 1) or α-Al2O3 except for graphene. On the other hand, calculation indicates that large area of graphene can be grown on h-BN.

  7. Detailed Structures of Hexagonal Diamond (lonsdaleite) and Wurtzite-type BN

    Science.gov (United States)

    Yoshiasa, Akira; Murai, Yu; Ohtaka, Osamu; Katsura, Tomoo

    2003-04-01

    Hexagonal diamond (hDIA) and wurtzite-type BN (wBN) powders were synthesized using a Kawai-type high-pressure apparatus and the essential details of their structures were examined by Reitveld refinements in order to investigate their thermodynamic stability and transition mechanism. X-ray diffraction profiles of the products were well explained by a mixture of hDIA and cubic diamond (cDIA) with stacking faults. The mass fraction of hDIA and cDIA was 50:50 for the products annealed between 800 and 1400°C and it became 20:80 for the product annealed at 1600°C. Temperatures higher than 1600°C seem to favor the formation of cDIA or to induce the conversion from hDIA to cDIA. Structure refinement revealed that a decrease and an increase in the basal and apical distances of C-C and B-N bonds in hDIA and wBN, respectively, are introduced by lowering the symmetry from cubic to hexagonal. Since the relative stability of wurtzite-type compounds largely depends on the distortion of the tetrahedral bond angle, the deviation from the ideal tetrahedron in both hDIA and wBN was refined to discuss their stability. The transition mechanism from graphite and graphite-like BN to hDIA and wBN is discussed by comparing the present results and those of previous simulation studies. Based on analogous features observed in the synthetic hDIA and lonsdaleite (natural hDIA found in meteorites), the formation mechanism of hDIA in meteorites is proposed.

  8. Vacuolar iron transporter BnMEB2 is involved in enhancing iron tolerance of Brassica napus

    Directory of Open Access Journals (Sweden)

    Wei Zhu

    2016-09-01

    Full Text Available Iron toxicity is a major nutrient disorder that severely affects crop development and yield. Vacuolar detoxification of metal stress is an important strategy for plants to survive and adapt to this adverse environment. Vacuolar iron transporter (VIT members are involved in this process and play essential roles in iron storage and transport. In this study, a rapeseed VIT gene BnMEB2 (BnaC07g30170D was identified. BnMEB2 is a homolog to Arabidopsis MEB2 (At5g24290 and acts as a detoxifier in vacuolar sequestration of divalent metal. Transient expression analysis revealed that BnMEB2 was localized to the vacuolar membrane. Q-PCR detection showed a high expression of BnMEB2 in mature (60-day-old leaves and could be obviously induced by exogenous iron stress in both roots and leaves. Over-expressed BnMEB2 in both Arabidopsis wild type and meb2 mutant seedlings resulted in greatly improved iron tolerability with no significant changes in the expression level of other vacuolar iron transporter genes. The mutant meb2 grew slowly and its root hair elongation was inhibited under high iron concentration condition while BnMEB2 over-expressed transgenic plants of the mutant restored the phenotypes with apparently higher iron storage in roots and dramatically increased iron content in the whole plant. Taken together, these results suggested that BnMEB2 was a VIT gene in rapeseed which was necessary for safe storage and vacuole detoxification function of excess iron to enhance the tolerance of iron toxicity. This research sheds light on a potentially new strategy for attenuating hazardous metal stress from environment and improving iron biofortification in Brassicaceae crops.

  9. Laser-based diagnostics applied to the study of BN nanotubes synthesis.

    Science.gov (United States)

    Cau, M; Dorval, N; Attal-Trétout, B; Cochon, J L; Cao, B; Bresson, L; Jaffrennou, P; Silly, M; Loiseau, A; Obraztsova, E D

    2008-11-01

    The boron nitride nanotubes (BNNTs) synthesis, using CO2-laser vaporization of a BN target under nitrogen gas, is investigated by UV-laser induced fluorescence (LIF) of the vapor phase and UV-Rayleigh scattering (RS) of the gas-suspended nanoparticles. The LIF signal from B atoms is mainly detected in the 1.5 mm-thick region above the BN target. It originates from a boron-rich vapor region confined near the hot boron droplet formed at the target surface. Then, recombination between hot boron and N2 gas occurs through a fast condensation process as revealed by both the depletion of B atoms from the vapor phase and the RS signal arising from the grown BN nanoparticles. Fluorescence spectra exhibit a strong peak at 250 nm due to boron fluorescence and mainly to nanoparticles Rayleigh scattering. A narrow peak is observed at 210 nm and a broader peak at 189 nm. These bands are tentatively assigned to fluorescence or photoluminescence (PL) from gaseous or solid BN species respectively since both gas and solid phases coexist in the plume due to the rapid cooling process. Two very weak bands occur at 308 nm and 350 nm. They are related to PL of defects bands from BN nanostructures on the basis of ex situ PL spectra of h-BN crystallites and multi-wall BNNTs. Detection of oxygen impurities is shown feasible through LIF from BO radical which is detected just above the BN target evaporated under vacuum pressure (approximately 1 mbar). An optical diagnostic strategy is demonstrated from these first in situ observations during BNNTs synthesis.

  10. Thermal Conductivity of Epoxy Resin Composites Filled with Combustion Synthesized h-BN Particles.

    Science.gov (United States)

    Chung, Shyan-Lung; Lin, Jeng-Shung

    2016-05-20

    The thermal conductivity of epoxy resin composites filled with combustion-synthesized hexagonal boron nitride (h-BN) particles was investigated. The mixing of the composite constituents was carried out by either a dry method (involving no use of solvent) for low filler loadings or a solvent method (using acetone as solvent) for higher filler loadings. It was found that surface treatment of the h-BN particles using the silane 3-glycidoxypropyltrimethoxysilane (GPTMS) increases the thermal conductivity of the resultant composites in a lesser amount compared to the values reported by other studies. This was explained by the fact that the combustion synthesized h-BN particles contain less -OH or active sites on the surface, thus adsorbing less amounts of GPTMS. However, the thermal conductivity of the composites filled with the combustion synthesized h-BN was found to be comparable to that with commercially available h-BN reported in other studies. The thermal conductivity of the composites was found to be higher when larger h-BN particles were used. The thermal conductivity was also found to increase with increasing filler content to a maximum and then begin to decrease with further increases in this content. In addition to the effect of higher porosity at higher filler contents, more horizontally oriented h-BN particles formed at higher filler loadings (perhaps due to pressing during formation of the composites) were suggested to be a factor causing this decrease of the thermal conductivity. The measured thermal conductivities were compared to theoretical predictions based on the Nielsen and Lewis theory. The theoretical predictions were found to be lower than the experimental values at low filler contents ( 60 vol %).

  11. Diamond and cBN hybrid and nanomodified cutting tools with enhanced performance: Development, testing and modelling

    DEFF Research Database (Denmark)

    Loginov, Pavel; Mishnaevsky, Leon; Levashov, Evgeny

    2015-01-01

    The potential of enhancement of superhard steel and cast iron cutting tool performance on the basis of microstuctural modifications of the tool materials is studied. Hybrid machining tools with mixed diamond and cBN grains, as well as machining tool with composite nanomodified metallic binder...... are developed, and tested experimentally and numerically. It is demonstrated that both combination of diamond and cBN (hybrid structure) and nanomodification of metallic binder (with hexagonal boron nitride/hBN platelets) lead to sufficient improvement of the cast iron machining performance. The superhard tools...... with 25% of diamond replaced by cBN grains demonstrate 20% increased performance as compared with pure diamond machining tools, and more than two times higher performance as compared with pure cBN tools. Further, cast iron machining efficiency of the wheels modified by hBN particles was 80% more efficient...

  12. Pulse electric current sintering of cubic boron nitride/tungsten carbide–cobalt (cBN/WC–Co) composites: Effect of cBN particle size and volume fraction on their microstructure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bo, E-mail: xiaoboking@gmail.com [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xianning West Road No. 28, Xi' an 710049, Shaanxi Province (China); State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi' an Jiaotong University, Xianning West Road No. 28, Xi' an 710049, Shaanxi Province (China); Qin, Yi [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xianning West Road No. 28, Xi' an 710049, Shaanxi Province (China); Jin, Feng [State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi' an Jiaotong University, Xianning West Road No. 28, Xi' an 710049, Shaanxi Province (China); Yang, Jian-Feng, E-mail: yang155@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xianning West Road No. 28, Xi' an 710049, Shaanxi Province (China); Ishizaki, Kozo [Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka 940-2188 (Japan)

    2014-06-01

    Cubic boron nitride/tungsten carbide–cobalt (cBN/WC–Co) composites were fabricated by pulse electric current sintering (PECS), using Ni–P as sintering additives to promote low temperature densification. The effect of cBN particle size and volume fraction on the densification, microstructure and mechanical properties of WC–Co composites was investigated. There was no phase transformation from cBN to hBN (hexagonal BN) with low-hardness due to low sintering temperature (1100–1200 °C) and short sintering time. Smaller cBN particle led to lower sinter-ability of the composites due to its high specific surface area. The 30 vol% 10–14 µm cBN/WC–Co composite (P14V30) exhibited high hardness (18.3 GPa, 1200 °C) and high fracture toughness (15.6 MP·m{sup 1/2}, 1000 °C). The high hardness resulted from the homogeneously dispersed cBN particles, which had a good bonding with the WC matrix. Increased fracture toughness was mainly attributed to crack deflection or bridging and pullout of cBN grains.

  13. Investigation of structure and mechanical properties of plasma vapor deposited nanocomposite TiBN films

    Science.gov (United States)

    Han, Bin; Neena, D.; Wang, Zesong; Kondamareddy, K. k.; Li, Na; Zuo, Wenbin; Yan, Shaojian; Liu, Chuansheng; Fu, Dejun

    2017-04-01

    TiBN coatings have huge potential applications as they have excellent properties with increasing modern industrial requirements. Nanocomposite TiBN coatings were synthesized on cemented carbide, high speed steel and Si substrates by using cathodic arc plasma ion plating from pure TiB2 ceramic targets. The structure and mechanical properties of the TiBN coatings were significantly influenced by the nitrogen partial pressure. Rutherford backscattering spectrometry demonstrates that the nitrogen content of the coating varied from 2.8% to 34.5% and high-resolution electron microscopy images reveal that all coatings have the characteristic of nanocrystals embedded in an amorphous matrix. The root-mean-square roughness of the coatings increases from 3.73 to 14.64 nm and the coefficients of friction of the coatings at room temperature vary from 0.54 to 0.73 with increasing nitrogen partial pressure. The microhardness of the coating increases up to 35.7 GPa at 10 sccm N2 flow rate. The smallest wear rate is 2.65 × 10-15 m3 N-1 m-1 which indicates that TiBN coatings have excellent wear resistance. The adhesion test revealed that the TiBN coatings have good adhesion at low nitrogen partial pressure.

  14. Effect of substrate temperature and gas flow ratio on the nanocomposite TiAlBN coating

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Z. M., E-mail: azmr@utem.edu.my; Kwan, W. L., E-mail: kwailoon86@gmail.com; Juoi, J. M., E-mail: jariah@utem.edu.my [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia)

    2016-07-19

    Nanocomposite TiAlBN (nc-TiAlBN) coatings were successfully deposited via RF magnetron sputtering by varying the nitrogen-to-total gas flow ratio (R{sub N}), and substrate temperature (T{sub S}). All coatings were deposited on AISI 316 substrates using single Ti-Al-BN hot-pressed disc as a target. The grain size, phases, and chemical composition of the coatings were evaluated using glancing angle X-ray diffraction analysis (GAXRD) and X-ray photoelectron spectroscopy (XPS). Results showed that the grains size of the deposited nc-TiAlBN coatings were in the range of 3.5 to 5.7 nm and reached a nitride saturation state as early as 15 % R{sub N}. As the nitrogen concentration decreases, boron concentration increased from 9 at.% to 16.17 at.%. and thus, increase the TiB{sub 2} phase within the coatings. The T{sub S}, however, showed no significant effect either on the crystallographic structure, grain size, or in the chemical composition of the deposited nc-TiAlBN coating.

  15. Electrical and Thermal Transport in Coplanar Polycrystalline Graphene-hBN Heterostructures.

    Science.gov (United States)

    Barrios-Vargas, José Eduardo; Mortazavi, Bohayra; Cummings, Aron W; Martinez-Gordillo, Rafael; Pruneda, Miguel; Colombo, Luciano; Rabczuk, Timon; Roche, Stephan

    2017-03-08

    We present a theoretical study of electronic and thermal transport in polycrystalline heterostructures combining graphene (G) and hexagonal boron nitride (hBN) grains of varying size and distribution. By increasing the hBN grain density from a few percent to 100%, the system evolves from a good conductor to an insulator, with the mobility dropping by orders of magnitude and the sheet resistance reaching the MΩ regime. The Seebeck coefficient is suppressed above 40% mixing, while the thermal conductivity of polycrystalline hBN is found to be on the order of 30-120 Wm(-1) K(-1). These results, agreeing with available experimental data, provide guidelines for tuning G-hBN properties in the context of two-dimensional materials engineering. In particular, while we proved that both electrical and thermal properties are largely affected by morphological features (e.g., by the grain size and composition), we find in all cases that nanometer-sized polycrystalline G-hBN heterostructures are not good thermoelectric materials.

  16. Graphene hot-electron light bulb: incandescence from hBN-encapsulated graphene in air

    Science.gov (United States)

    Son, Seok-Kyun; Šiškins, Makars; Mullan, Ciaran; Yin, Jun; Kravets, Vasyl G.; Kozikov, Aleksey; Ozdemir, Servet; Alhazmi, Manal; Holwill, Matthew; Watanabe, Kenji; Taniguchi, Takashi; Ghazaryan, Davit; Novoselov, Kostya S.; Fal’ko, Vladimir I.; Mishchenko, Artem

    2018-01-01

    The excellent electronic and mechanical properties of graphene allow it to sustain very large currents, enabling its incandescence through Joule heating in suspended devices. Although interesting scientifically and promising technologically, this process is unattainable in ambient environment, because graphene quickly oxidises at high temperatures. Here, we take the performance of graphene-based incandescent devices to the next level by encapsulating graphene with hexagonal boron nitride (hBN). Remarkably, we found that the hBN encapsulation provides an excellent protection for hot graphene filaments even at temperatures well above 2000 K. Unrivalled oxidation resistance of hBN combined with atomically clean graphene/hBN interface allows for a stable light emission from our devices in atmosphere for many hours of continuous operation. Furthermore, when confined in a simple photonic cavity, the thermal emission spectrum is modified by a cavity mode, shifting the emission to the visible range spectrum. We believe our results demonstrate that hBN/graphene heterostructures can be used to conveniently explore the technologically important high-temperature regime and to pave the way for future optoelectronic applications of graphene-based systems.

  17. Physico-mechanical and tribological properties of Cu/h-BN nanocomposites synthesized by PM route

    Energy Technology Data Exchange (ETDEWEB)

    Elkady, Omayma A.M. [Powder Metallurgy Division, Manufacturing Department, Central Metallurgical R and D Institute, P.O. 87 Helwan, 11421 Cairo (Egypt); Abu-Oqail, Ahmed [Mechanical Department, Faculty of Industrial Education, BeniSuef University (Egypt); Ewais, Emad M.M., E-mail: dr_ewais@hotmail.com [Refractory and Ceramic Materials Division, Advanced Materials Department, Central Metallurgical R and D Institute, P.O. 87 Helwan, 11421 Cairo (Egypt); El-Sheikh, M. [Mechanical Department, Faculty of Industrial Education, BeniSuef University (Egypt)

    2015-03-15

    Highlights: • Addition of h-BN to Cu nanoparticles is very novel. • Composites formed under 700 MPa and sintered at 950 °C/2 h gave the highest values. • The studied composites recorded anisotropic mechanical parameters. • These composites are expected to find a wide variety of advanced applications. - Abstract: Manufacture of self-lubricating net-shapes composites has become an important issue in recent years due to their unique tribological properties which make them suitable for a wide variety of advanced applications. In this work, nano-copper with 2.5, 5, 7.5 and 10 wt.% of hexagonal boron nitride (h-BN) composites were prepared by powder metallurgy (P/M) technology. These mixtures were uniaxially pressed by applying different loads (300–1200 MPa) and sintered at a temperature range of 900–1000 °C. The outcomes indicate that the relative green density is directly proportional to the applied load and inversely proportional to the content of h-BN. Cu/h-BN composites formed under 700 MPa and sintered at 950 °C for 2 h recorded the highest relative density, hardness and compression strength. They are exhibited the lowest electrical resistivity, wear rate and coefficient of friction. These results attributed to h-BN characteristics such as low density, high dielectric constant and lubricity.

  18. Tunability of 1/f Noise at Multiple Dirac Cones in hBN Encapsulated Graphene Devices.

    Science.gov (United States)

    Kumar, Chandan; Kuiri, Manabendra; Jung, Jeil; Das, Tanmoy; Das, Anindya

    2016-02-10

    The emergence of multiple Dirac cones in hexagonal boron nitride (hBN)-graphene heterostructures is particularly attractive because it offers potentially better landscape for higher and versatile transport properties than the primary Dirac cone. However, the transport coefficients of the cloned Dirac cones is yet not fully characterized and many open questions, including the evolution of charge dynamics and impurity scattering responsible for them, have remained unexplored. Noise measurements, having the potential to address these questions, have not been performed to date in dual-gated hBN-graphene-hBN devices. Here, we present the low-frequency 1/f noise measurements at multiple Dirac cones in hBN encapsulated single and bilayer graphene in dual-gated geometry. Our results reveal that the low-frequency noise in graphene can be tuned by more than two-orders of magnitude by changing carrier concentration as well as by modifying the band structure in bilayer graphene. We find that the noise is surprisingly suppressed at the cloned Dirac cone compared to the primary Dirac cone in single layer graphene device, while it is strongly enhanced for the bilayer graphene with band gap opening. The results are explained with the calculation of dielectric function using tight-binding model. Our results also indicate that the 1/f noise indeed follows the Hooge's empirical formula in hBN-protected devices in dual-gated geometry. We also present for the first time the noise data in bipolar regime of a graphene device.

  19. Enhanced Superhydrophobic Performance of BN-MoS2 Heterostructure Prepared via a Rapid, One-Pot Supercritical Fluid Processing.

    Science.gov (United States)

    Thangasamy, Pitchai; Partheeban, Thamodaran; Sudanthiramoorthy, Subramanian; Sathish, Marappan

    2017-06-20

    Fabrication of highly crystalline BN-MoS2 heterostructure with >95% yield was demonstrated using one-pot supercritical fluid processing within 30 min. The existence of 20-50 layers of BN-MoS2 in the prepared heterostructure was confirmed by AFM analysis. The HR-TEM imaging and mapping analysis revealed the well-melded BN and MoS2 nanosheets in the heterostructure. The drastic reduction in XRD line intensities corresponding to the (002) plane and broadening of the peaks for the BN system over MoS2 indicated the effective exfoliation and lateral size reduction in BN nanosheets during SCF processing. Also, the exfoliated MoS2 nanosheets are preferentially exposed rather than BN nanosheets; consequently, the MoS2 nanosheets sturdily covered BN nanosheets in the heterostructure. The exfoliated BN and MoS2 nanosheets with nanoscale roughness make the surface highly hydrophobic in nature. As a result, the BN-MoS2 heterostructure showed superior superhydrophobic performance with high water contact angle of 165.9°, which is much higher than the value reported in the literature.

  20. Microstructure Characteristics and Properties of HVOF Sprayed Ni-Based Alloy Nano-h-BN Self-Lubricating Composite Coatings

    OpenAIRE

    Xiaofeng Zhang; Long Zhang; Zhenyi Huang

    2015-01-01

    A Ni-based alloy/nano-h-BN self-lubricating composite coating was produced on medium carbon steel by high velocity oxygen fuel (HVOF) spraying technique. The powder feedstocks for HVOF spraying were prepared by ball milling and agglomerated the nano-h-BN with Ni-based alloy powders. The microstructure and mechanical properties of coatings have been investigated. With the increasing of h-BN contents, some delaminations appeared gradually in the coatings and a continuous network with h-BN phase...

  1. CBT4BN versus CBTF2F: Comparison of Online versus Face-To-FaceTreatment for Bulimia Nervosa

    Science.gov (United States)

    Bulik, Cynthia M.; Marcus, Marsha D.; Zerwas, Stephanie; Levine, Michele D.; Hofmeier, Sara; Trace, Sara E.; Hamer, Robert M.; Zimmer, Benjamin; Moessner, Markus; Kordy, Hans

    2012-01-01

    Cognitive-behavioral therapy (CBT) is currently the “gold standard” for treatment of bulimia nervosa (BN), and is effective for approximately 40–60% of individuals receiving treatment; however, the majority of individuals in need of care do not have access to CBT. New strategies for service delivery of CBT and for maximizing maintenance of treatment benefits are critical for improving our ability to treat BN. This clinical trial is comparing an Internet-based version of CBT (CBT4BN) in which group intervention is conducted via therapeutic chat group with traditional group CBT (CBTF2F) for BN conducted via face-to-face therapy group. The purpose of the trial is to determine whether manualized CBT delivered via the Internet is not inferior to the gold standard of manualized group CBT. In this two-site randomized controlled trial, powered for non-inferiority analyses, 180 individuals with BN are being randomized to either CBT4BN or CBTF2F. We hypothesize that CBT4BN will not be inferior to CBTF2F and that participants will value the convenience of an online intervention. If not inferior, CBT4BN may be a cost-effective approach to service delivery for individuals requiring treatment for BN. PMID:22659072

  2. Harder than Diamond: Superior Indentation Strength of Wurtzite BN and Lonsdaleite

    Science.gov (United States)

    Pan, Zicheng; Sun, Hong; Zhang, Yi; Chen, Changfeng

    2009-02-01

    Recent indentation experiments indicate that wurtzite BN (w-BN) exhibits surprisingly high hardness that rivals that of diamond. Here we unveil a novel two-stage shear deformation mechanism responsible for this unexpected result. We show by first-principles calculations that large normal compressive pressures under indenters can compel w-BN into a stronger structure through a volume-conserving bond-flipping structural phase transformation during indentation which produces significant enhancement in its strength, propelling it above diamond’s. We further demonstrate that the same mechanism also works in lonsdaleite (hexagonal diamond) and produces superior indentation strength that is 58% higher than the corresponding value of diamond, setting a new record.

  3. Controlling the orientation of nucleobases by dipole moment interaction with graphene/h-BN interfaces

    KAUST Repository

    Vovusha, Hakkim

    2018-02-08

    The interfaces in 2D hybrids of graphene and h-BN provide interesting possibilities of adsorbing and manipulating atomic and molecular entities. In this paper, with the aid of density functional theory, we demonstrate the adsorption characteristics of DNA nucleobases at different interfaces of 2D hybrid nanoflakes of graphene and h-BN. The interfaces provide stronger binding to the nucleobases in comparison to pure graphene and h-BN nanoflakes. It is also revealed that the individual dipole moments of the nucleobases and nanoflakes dictate the orientation of the nucleobases at the interfaces of the hybrid structures. The results of our study point towards a possible route to selectively control the orientation of individual molecules in biosensors.

  4. BN/BNSiO2 sputtering yield shape profiles under stationary plasma thruster operating conditions

    Directory of Open Access Journals (Sweden)

    M. Ranjan

    2016-09-01

    Full Text Available Quartz Crystal Microbalance (QCM is used to measure the volumetric and total sputtering yield of Boron Nitride (BN and Boron Nitride Silicon Dioxide (BNSiO2 bombarded by Xenon ions in the energy range of 100 eV to 550 eV. Sputtering yield shape profiles are reported at various angles of incidence 0-85° with surface normal and compared with modified Zhang model. The yield shape profile is found to be symmetric at normal incidence and asymmetric at oblique incidence. Both the materials show a sudden jump in the sputtering yield above 500 eV and at an angle of incidence in the range of 45-65°. Erosion of BN at as low as 74 eV ion energy is predicted using generalized Bohdansky model. BNSiO2 show a marginally higher sputtering yield compare to BN.

  5. Modulation of the electron transport properties in graphene nanoribbons doped with BN chains

    Directory of Open Access Journals (Sweden)

    Wu Liu

    2014-06-01

    Full Text Available Using density-functional theory and the non-equilibrium Green's function method, the electron transport properties of zigzag graphene nanoribbons (ZGNRs doped with BN chains are studied by systematically calculating the energy band structure, density of states and the transmission spectra for the systems. The BN chains destroyed the electronic transport properties of the ZGNRs, and an energy gap appeared for the ZGNRs, and displayed variations from a metal to a wide-gap semiconductor. With an increase in the number of BN chains, the band gap increased gradually in the band structure and the transmission coefficient decreased near the Fermi surface. Additionally, the doping position had a significant effect on the electronic properties of the ZGNRs.

  6. GaN and AlGaN/GaN heterostructures grown on two dimensional BN templates

    Science.gov (United States)

    Snure, Michael; Siegel, Gene; Look, David C.; Paduano, Qing

    2017-04-01

    Two dimension materials, like BN and graphene, have been shown to be excellent templates for the growth and fabrication of freestanding III-nitride materials. In this paper we study the effects of BN morphology on GaN and AlGaN/GaN heterostructures grown on these templates. The crystallinity, transport, and optical properties of the GaN layer are examined and found to be well correlated to the BN template. The self-separation of GaN from the BN/sapphire template is also connected to morphology, resulting in freestanding GaN layers. Transport properties of Si doped GaN and AlGaN/GaN heterostructures were examined for different BN templates. The bulk GaN mobility was closely linked to the morphology of the BN template resulting in room temperature mobility from 395 to 520 cm2/Vs. The range in 3D mobility can be linked to increased dislocation densities in GaN grown on rougher BN templates. High 2DEG mobility ( 2000 cm2/Vs at 300 K) is achieved in AlGaN/GaN grown on atomically smooth BN templates, with a sheet electron density of 1×1013 cm-2, comparable to values obtained on conventional substrates. Samples grown on BN/sapphire showed mobilities (at 9 K) from 33000 cm2/Vs to 15200 cm2/Vs depending on BN roughness. The differences are associated with variations in AlGaN/GaN interface-roughness scattering and dislocation density due to the BN template morphology.

  7. The effect of incorporated self-lubricated BN(h) particles on the tribological properties of Ni-P/BN(h) composite coatings

    Science.gov (United States)

    Hsu, Chih-I.; Hou, Kung-Hsu; Ger, Ming-Der; Wang, Gao-Liang

    2015-12-01

    Ni-P/BN(h) composite coatings are prepared by means of the conventional electroless plating from the bath containing up to 10.0 g/l of hexagonal boron nitride particles with size 0.5 μm. The Ni-P coating is also prepared as a comparison. Cationic surfactant cetyltrimethylammonium bromide (CTAB) is used to stabilize the electrolyte, and the optimum CTAB concentration resulting in a nonagglomerated dispersion of particles is obtained using a dispersion stability analyzer. Morphology of the coatings and the effect of incorporated particles on coating structure and composition are investigated via scanning electron microscopy, field emission electron probe micro-analyzer and X-ray diffraction analysis. Hardness, roughness, friction coefficient and wear resistance of the coatings are also evaluated using Vickers microhardness tester, atomic force microscopy and ball-on disk machine. The presence of CTAB in the depositing bath has a positive effect on the surface roughness and performance of Ni-P/BN(h) composite coatings. The friction and wear tests results show that incorporation of 14.5 vol% BN(h) particles into the Ni-P coating lowers the coating friction coefficient by about 75% and the wear resistance of the Ni-P composites is approximately 10 times higher than Ni-P coating.

  8. Map-based cloning reveals the complex organization of the BnRf locus and leads to the identification of BnRf(b), a male sterility gene, in Brassica napus.

    Science.gov (United States)

    Deng, Zonghan; Li, Xi; Wang, Zengzeng; Jiang, Yingfen; Wan, Lili; Dong, Faming; Chen, Fengxiang; Hong, Dengfeng; Yang, Guangsheng

    2016-01-01

    Sequencing of BAC clones reveals the complex organization of the BnRf locus and allowed us to clone BnRf (b) , which encodes a nucleus-localized chimeric protein BnaA7.mtHSP70-1-like. The male sterility in an extensively used genic male sterility (GMS) line (9012A) in Brassica napus was regarded to be conferred by BnMs3/Bnms3 and the multiallelic BnRf locus including three alleles. We previously mapped BnRf to a 13.8 kb DNA fragment on the B. napus chromosome A7. In the present study, we isolated bacterial artificial chromosome clones individually covering the restorer allele BnRf (a) and the male-sterile allele BnRf (b) , and revealed that the candidate regions of BnRf (a) and BnRf (b) show complex structural variations relative to the maintainer allele BnRf (c). By analyzing the recombination events and the newly developed markers, we delimited BnRf (a) to a 35.9 kb DNA fragment that contained seven predicted open-reading frames (ORFs). However, genetic transformation of the ORF G14 from both the male-sterile and restorer lines into wild-type Arabidopsis plants led to a stable male-sterile phenotype matching a 9012A-derived GMS line (RG206A); moreover, the male sterility caused by G14 could be fully recovered by the restorer gene BnMs3. These facts indicate that BnRf (b) corresponds to G14 while BnRf (a) likely associates with another flanking ORF. G14 encodes a nucleus-localized chimeric protein designated as BnaA7.mtHSP70-1-like. Ectopic expression of G14 in Arabidopsis negatively regulates some vital genes responsible for tapetum degeneration, and delayed programmed cell death of tapetum and led to the developmental arrest of tetrads. Our work not only presents new insights on the hereditary model of sterility control but also lays a solid foundation for dissecting the molecular basis underlying male sterility and restoration in 9012A.

  9. 78 FR 28836 - Vulcan/BN Geothermal Power Company; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2013-05-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Vulcan/BN Geothermal Power Company; Supplemental Notice That Initial Market... in the above-referenced proceeding of Vulcan/BN Geothermal Power Company's application for market...

  10. Generated photocatalytic performance of h-BN sheet by coupling with reduced graphene oxide/fluorid: A DFT study

    Science.gov (United States)

    Lu, Baichuan; Jia, Jun; Guo, Fengjuan; Li, Dongyang; Zhao, Yunhao; Zhao, Xian; Gao, Hongtao

    2017-09-01

    First-principles calculation based on density functional theory (DFT) was performed to investigate the enhanced photocatalytic mechanism and electronic properties of hexagonal boron nitride (h-BN) sheet by coupling with reduced graphene oxide (RGO) or reduced graphene fluorid (RGF). It is demonstrated that the combination of h-BN with RGO(F) is thermodynamically favorable. The spatial configurations of O and F atoms played a key role in modifying the electronic structure and properties of h-BN/RGO(F) composites. The interaction between h-BN and RGO(F) sheets caused charge accumulation on the side of h-BN layer and charge depletion on the lower side of RGO(F) sheet. There formed a heterjunction between the interface, which could improve the separation efficiency of photogenerated carriers and inhibit their combination. Both valence band edge and conduction band edge positions of h-BN/RGO(F) composites were characterized to illustrate the enhanced oxidation-reduction performance mechanism. The theoretical investigation could provide valuable information for thoroughly understanding the mechanism of the exceptional performance of h-BN/RGO(F) composites compared to the h-BN sheet.

  11. Thermal transport through Zn3P2 nanowire-BN microparticle/nanoparticle composites and hybrids

    Science.gov (United States)

    Vasiraju, Venkata; Norris, David; Vaddiraju, Sreeram

    2017-07-01

    Composites and hybrids of BN and Zn3P2 nanowires were made by consolidating respectively BN micropowder-Zn3P2 nanowire mixtures and non-conformally BN decorated Zn3P2 nanowires. The intent here is to study whether mere solid-state mixing of a thermal conductor and a thermal insulator leads to the engineering of the thermal conductivities of the resulting composites and hybrids. The results demonstrated that contrary to intuition, mere mixing of two materials, a thermal conductor (BN) and a thermal insulator (Zn3P2 nanowires), does not result in composites and hybrids that have thermal conductivities higher than those of the thermal insulator and lower than those of the thermal conductor. This contrary result is especially true in instances where microparticles or nanoparticles of a high thermal conductivity material are introduced into a matrix of the thermal insulator for achieving spatially uniform composites/hybrids and engineering the resulting materials’ thermal conductivities. Here, both the size of the filler material and the type of interfaces formed between the matrix and the filler material play a major role in determining the ultimate thermal conductivities of the composites/hybrids. Imperfect interface formed between materials that have high lattice mismatches lead to lowering of the thermal conductivities of the composites/hybrids.

  12. Significant stress reduction of cBN layers upon ion irradiation at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Weidner, S. [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Ye, J. [Karlsruher Institut fuer Technologie (KIT), Institut fuer Angewandte Materialien-Angewandte Werkstoffphysik (IAM-AWP), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Geburt, S.; Ronning, C. [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Ulrich, S., E-mail: sven.ulrich@kit.edu [Karlsruher Institut fuer Technologie (KIT), Institut fuer Angewandte Materialien-Angewandte Werkstoffphysik (IAM-AWP), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2012-06-01

    Superhard cubic boron nitride (cBN) thin films can be synthesized nowadays by a variety of PVD and PECVD techniques. Their applications are however still impeded by extremely high film stresses, typically above 20 GPa, resulting from a severe ion bombardment of the growing surface being obligatory for the formation of the cubic phase. This stress was shown to be partly released by an addition of oxygen during film deposition, with deposited films containing approx. 5 at.% of oxygen embedded into the cubic lattice. In this study, further impacts on the stress of such oxygen-incorporated cBN films (cBN:O) are studied by means of post-deposition high-energy implantation of oxygen-, neon-, and krypton-ions, respectively. It is shown, in particular, that the irradiation by krypton ions at 600 K temperature can produce a significant stress reduction of cBN:O from 10 GPa down to 4 GPa, without inducing observable transformation of existing cubic structure into the hexagonal phase.

  13. Effect of magnesium aluminum silicate glass on the thermal shock resistance of BN matrix composite ceramics

    NARCIS (Netherlands)

    Cai, Delong; Jia, Dechang; Yang, Zhihua; Zhu, Qishuai; Ocelik, Vaclav; Vainchtein, Ilia D.; De Hosson, Jeff Th M.; Zhou, Yu

    The effects of magnesium aluminum silicate (MAS) glass on the thermal shock resistance and the oxidation behavior of h-BN matrix composites were systematically investigated at temperature differences from 600 degrees C up to 1400 degrees C. The retained strength rate of the composites rose with the

  14. Fast Suzuki-Miyaura cross-coupling reaction with hexacationic triarylphosphine Bn-Dendriphos as ligand

    NARCIS (Netherlands)

    Snelders, D.J.M.; Kreiter, R.; Firet, J.J.; van Koten, G.; Klein Gebbink, R.J.M.

    2008-01-01

    The application of hexa[(dimethylamino)methyl]-functionalized triphenylphosphine (1) and its benzylammonium salt, Bn-Dendriphos (2), in the Suzuki-Miyaura cross-coupling of aryl bromides with arylboronic acids is described. The 3,5-bis[(benzyldimethylammonio)methyl] substitution pattern in 2 leads

  15. Atomically Sharp Interface in an h-BN-epitaxial graphene van der Waals Heterostructure

    Science.gov (United States)

    Sediri, Haikel; Pierucci, Debora; Hajlaoui, Mahdi; Henck, Hugo; Patriarche, Gilles; Dappe, Yannick J.; Yuan, Sheng; Toury, Bérangère; Belkhou, Rachid; Silly, Mathieu G.; Sirotti, Fausto; Boutchich, Mohamed; Ouerghi, Abdelkarim

    2015-01-01

    Stacking various two-dimensional atomic crystals is a feasible approach to creating unique multilayered van der Waals heterostructures with tailored properties. Herein for the first time, we present a controlled preparation of large-area h-BN/graphene heterostructures via a simple chemical deposition of h-BN layers on epitaxial graphene/SiC(0001). Van der Waals forces, which are responsible for the cohesion of the multilayer system, give rise to an abrupt interface without interdiffusion between graphene and h-BN, as shown by X-ray Photoemission Spectroscopy (XPS) and direct observation using scanning and High-Resolution Transmission Electron Microscopy (STEM/HRTEM). The electronic properties of graphene, such as the Dirac cone, remain intact and no significant charge transfer i.e. doping, is observed. These results are supported by Density Functional Theory (DFT) calculations. We demonstrate that the h-BN capped graphene allows the fabrication of vdW heterostructures without altering the electronic properties of graphene. PMID:26585245

  16. Amplification of the active site of BnLIP3 gene of Brassica napus L ...

    African Journals Online (AJOL)

    Lipases are useful enzymes that are responsible for the hydrolysis of triacylglycerides and play an important role in plant growth. In this study, we report a rapid molecular method to amplify a partial sequence of the lipase class 3 family designated BnLIP3 gene of Brassica napus L. in order to follow its expression and ...

  17. Role of Plasma Temperature and Residence Time in Stagnation Plasma Synthesis of c-BN Nanopowders

    Science.gov (United States)

    2013-01-01

    containing precursors and relies on self-assembly of the atoms. Bartl et al. 13 hypothesized necessary conditions for c-BN growth in CVD...and . From stream function analysis, the Cauchy- Riemann equations are determined as: , (4.14

  18. Overcoming barriers to role transition during an online post LPN to BN program.

    Science.gov (United States)

    Melrose, Sherri; Gordon, Kathryn

    2011-01-01

    Canadian Licensed Practical Nurses continuing their education in an online Bachelor of Nursing program face unique barriers as they transition towards a new and more complex nursing role. This qualitative descriptive study explored Post Licensed Practical Nurse to Bachelor of Nursing (Post LPN to BN) students' perceptions of their experiences during their education. George Kelly's (1955/1991) psychology of personal constructs, which seeks to understand how individuals perceive the world around them, was the theoretical framework for this three year longitudinal project in which 10 Post LPN to BN students were interviewed at the beginning, middle and end of their program. Transcripts from the interviews were analyzed and three key themes are presented to illustrate barriers that Post LPN to BN students faced and the strategies they implemented to overcame them. First, workplace mentors helped Post LPN to BN students apply their learning. Second, personal learning goals sustained their motivation. Third, time management strategies included terminating full time employment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. B-N as a C-C substitute in aromatic systems

    National Research Council Canada - National Science Library

    Bosdet, Michael J.D; Piers, Warren E

    2009-01-01

    ... electronic properties and chemistry. Since the pioneering work of Dewar some 50 years ago, the relationship between B-N and C-C and the wealth of parent all-carbon aromatics has captured the imagination of organic, inorganic, materials...

  20. CBT4BN: A Randomized Controlled Trial of Online Chat and Face-to-Face Group Therapy for Bulimia Nervosa

    Science.gov (United States)

    Zerwas, Stephanie C.; Watson, Hunna J.; Hofmeier, Sara M.; Levine, Michele D.; Hamer, Robert M.; Crosby, Ross D.; Runfola, Cristin D.; Peat, Christine M.; Shapiro, Jennifer R.; Zimmer, Benjamin; Moessner, Markus; Kordy, Hans; Marcus, Marsha D.; Bulik, Cynthia M.

    2016-01-01

    Objective Although cognitive-behavioral therapy (CBT) represents the first-line evidence-based psychotherapy for bulimia nervosa (BN), most individuals seeking treatment do not have access to this specialized intervention. We compared an Internet-based manualized version of CBT group therapy for BN conducted via a therapeutic chat group (CBT4BN) to the same treatment conducted via a traditional face-to-face group therapy (CBTF2F). Method In a two-site, randomized, controlled non-inferiority trial, we tested the hypothesis that CBT4BN would not be inferior to CBTF2F. One hundred forty-nine adult patients with BN (2.6% males) received up to 16 sessions of group CBT over 20 weeks in either CBT4BN or CBTF2F and outcomes were compared at the end of treatment and 12-month follow-up. Results At the end of treatment, CBT4BN was inferior to CBTF2F in producing abstinence from binge eating and purging and in leading to reductions in the frequency of binge eating and purging. However, by 12-month follow-up, CBT4BN was mostly not inferior to CBTF2F. Participants in the CBT4BN condition, but not CBTF2F, continued to reduce their binge-eating and purging frequency from end of treatment to 12-month follow-up. Conclusions CBT delivered online in a group chat format appears to be an efficacious treatment for BN although the trajectory of recovery may be slower than face-to-face group therapy. Online chat groups may increase accessibility of treatment and represent a cost-effective approach to service delivery. However, barriers in service delivery such as state-specific license and ethical guidelines for online therapists need to be addressed. PMID:27883997

  1. Growth and characterization of thick cBN coatings on silicon and tool substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bewilogua, K. [Fraunhofer Institute for Surface Engineering and Thin Films, D-38108 Braunschweig (Germany)]. E-mail: bew@ist.fraunhofer.de; Keunecke, M. [Fraunhofer Institute for Surface Engineering and Thin Films, D-38108 Braunschweig (Germany); Weigel, K. [Fraunhofer Institute for Surface Engineering and Thin Films, D-38108 Braunschweig (Germany); Wiemann, E. [Institute for Machine Tools and Factory Management, Technical University Berlin (Germany)

    2004-12-22

    Recently some research groups have achieved progress in the deposition of cubic boron nitride (cBN) coatings with a thickness of 2 {mu}m and more, which is necessary for cutting tool applications. In our laboratory, thick cBN coatings were sputter deposited on silicon substrates using a boron carbide target. Following a boron carbide interlayer (few 100 nm thick), a gradient layer with continuously increasing nitrogen content was prepared. After the cBN nucleation, the process parameters were modified for the cBN film growth to a thickness of more than 2 {mu}m. However, the transfer of this technology to technically relevant substrates, like cemented carbide cutting inserts, required some further process modifications. At first, a titanium interlayer had to be deposited followed by a more than 1-{mu}m-thick boron carbide layer. The next steps were identical to those on silicon substrates. The total coating thickness was in the range of 3 {mu}m with a 0.5- to nearly 1-{mu}m-thick cBN top layer. In spite of the enormous intrinsic stress, both the coatings on silicon and on cemented carbide exhibited a good adhesion and a prolonged stability in humid air. Oxidation experiments revealed a stability of the coating system on cemented carbide up to 700 deg. C and higher. Coated cutting inserts were tested in turning operations with different metallic workpiece materials. The test results will be compared to those of well-established cutting materials, like polycrystalline cubic boron nitride (PCBN) and oxide ceramics, considering the wear of coated tools.

  2. Recent advances in preparation, properties and device applications of two-dimensional h-BN and its vertical heterostructures

    Science.gov (United States)

    Yang, Huihui; Gao, Feng; Dai, Mingjin; Jia, Dechang; Zhou, Yu; Hu, Pingan

    2017-03-01

    Two-dimensional (2D) layered materials, such as graphene, hexagonal boron nitride (h-BN), molybdenum disulfide (MoS{}2 ), have attracted tremendous interest due to their atom-thickness structures and excellent physical properties. h-BN has predominant advantages as the dielectric substrate in FET devices due to its outstanding properties such as chemically inert surface, being free of dangling bonds and surface charge traps, especially the large-band-gap insulativity. h-BN involved vertical heterostructures have been widely exploited during the past few years. Such heterostructures adopting h-BN as dielectric layers exhibit enhanced electronic performance, and provide further possibilities for device engineering. Besides, a series of intriguing physical phenomena are observed in certain vertical heterostructures, such as superlattice potential induced replication of Dirac points, band gap tuning, Hofstadter butterfly states, gate-dependent pseudospin mixing. Herein we focus on the rapid developments of h-BN synthesis and fabrication of vertical heterostructures devices based on h-BN, and review the novel properties as well as the potential applications of the heterostructures composed of h-BN. Project supported by the National Natural Science Foundation of China (Nos. 61390502, 21373068), the National Basic Research Program of China (No. 2013CB632900), the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. 51521003), and the Self-Planned Task of State Key Laboratory of Robotics and System (No. SKLRS201607B).

  3. Negative Refraction with Superior Transmission in Graphene-Hexagonal Boron Nitride (hBN) Multilayer Hyper Crystal

    Science.gov (United States)

    Sayem, Ayed Al; Rahman, Md. Masudur; Mahdy, M. R. C.; Jahangir, Ifat; Rahman, Md. Saifur

    2016-01-01

    In this article, we have theoretically investigated the performance of graphene-hexagonal Boron Nitride (hBN) multilayer structure (hyper crystal) to demonstrate all angle negative refraction along with superior transmission. hBN, one of the latest natural hyperbolic materials, can be a very strong contender to form a hyper crystal with graphene due to its excellence as a graphene-compatible substrate. Although bare hBN can exhibit negative refraction, the transmission is generally low due to its high reflectivity. Whereas due to graphene’s 2D nature and metallic characteristics in the frequency range where hBN behaves as a type-I hyperbolic material, we have found graphene-hBN hyper-crystals to exhibit all angle negative refraction with superior transmission. Interestingly, superior transmission from the whole structure can be fully controlled by the tunability of graphene without hampering the negative refraction originated mainly from hBN. We have also presented an effective medium description of the hyper crystal in the low-k limit and validated the proposed theory analytically and with full wave simulations. Along with the current extensive research on hybridization of graphene plasmon polaritons with (hyperbolic) hBN phonon polaritons, this work might have some substantial impact on this field of research and can be very useful in applications such as hyper-lensing. PMID:27146561

  4. Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Mingjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Ren, Siming [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Chen, Jia; Liu, Shuan [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhang, Guangan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao, Haichao, E-mail: zhaohaichao@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xue, Qunji, E-mail: qjxue@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2017-03-01

    Highlights: • Hexagonal boron nitride nanosheets were well dispersed by using water-soluble carboxylated aniline trimer as dispersant. • The best corrosion performance of waterborne epoxy coatings was achieved with the addition of 1 wt% h-BN. • The decrease of the pores and defects of coating matrix inhibits the diffusion and water absorption of corrosive medium in the coating. - Abstract: Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT{sup −}) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT{sup −}, as proved by Raman and UV–vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 10{sup 6} Ω cm{sup 2}) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

  5. Deposition of B{sub 4}C/BCN/c-BN multilayered thin films by r.f. magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, G. [Laboratorio de Recubrimientos Duros del CDT-ASTIN SENA, Cali (Colombia); Caicedo, J.M. [Laboratorio de Recubrimientos Duros del CDT-ASTIN SENA, Cali (Colombia); Baca, E. [Departamento de Fisica, Universidad del Valle, A.A. 25360, Cali (Colombia); Prieto, P. [Departamento de Fisica, Universidad del Valle, A.A. 25360, Cali (Colombia)]. E-mail: pprieto@calima.univalle.edu.co; Balogh, A.G. [Institute for Material Science, Darmstadt University of Technology (Germany); Enders, S. [Max Plank Institute, Department of Material Research, Stuttgart (Germany)

    2006-01-03

    Thin films of cubic boron nitride (c-BN) and B{sub 4}C/BCN/c-BN multilayers, were deposited by r.f. (13.56 MHz) multi-target magnetron sputtering from high-purity (99.99%) h-BN and a (99.5%) B{sub 4}C targets, in an Ar (90%)/N{sub 2} (10%) gas mixture. Films were deposited onto silicon substrates with (100) orientations at 300 {sup o}C, with r.f. power density near 7 W/cm{sup 2}. In order to obtain the highest fraction of the c-BN phase, an r.f. substrate bias voltage between - 100 and - 300 V was applied during the initial nucleation process and - 50 to - 100 V during the film growth. Additionally, B{sub 4}C and BCN films were deposited and analyzed individually. For their deposition, we varied the bias voltage of the B{sub 4}C films between - 50 and - 250 V, and for the BCN coatings, the nitrogen gas flow from 3% to 12%. A 300-nm-thick TiN buffer layer was first deposited to improve the adhesion of all samples. X-ray diffraction patterns revealed the presence of c-BN (111) and h-BN phases. FTIR spectroscopy measurements indicate the presence of a peak at 780 cm{sup -} {sup 1} referred to as 'out-of-plane' h-BN vibration mode; another peak at 1100 cm{sup -} {sup 1} corresponds to the c-BN TO mode and the 'in-plane' vibration mode of the h-BN at 1400 cm{sup -} {sup 1}. BN films deposited at 300 deg. C at a pressure of 4.0 Pa and under - 150 V of nucleation r.f. bias, applied for 35 min, presented the highest c-BN fraction, near 85%. By using 32 layers, it was possible to deposit a 4.6-{mu}m-thick c-BN film with adequate mechanical properties and good adhesion to the substrate.

  6. BnSIP1-1, a Trihelix Family Gene, Mediates Abiotic Stress Tolerance and ABA Signaling in Brassica napus.

    Science.gov (United States)

    Luo, Junling; Tang, Shaohua; Mei, Fengling; Peng, Xiaojue; Li, Jun; Li, Xiaofei; Yan, Xiaohong; Zeng, Xinhua; Liu, Fang; Wu, Yuhua; Wu, Gang

    2017-01-01

    The trihelix family genes have important functions in light-relevant and other developmental processes, but their roles in response to adverse environment are largely unclear. In this study, we identified a new gene, BnSIP1-1, which fell in the SIP1 (6b INTERACTING PROTEIN1) clade of the trihelix family with two trihelix DNA binding domains and a fourth amphipathic α-helix. BnSIP1-1 protein specifically targeted to the nucleus, and its expression can be induced by abscisic acid (ABA) and different stresses. Overexpression of BnSIP1-1 improved seed germination under osmotic pressure, salt, and ABA treatments. Moreover, BnSIP1-1 decreased the susceptibility of transgenic seedlings to osmotic pressure and ABA treatments, whereas there was no difference under salt stress between the transgenic and wild-type seedlings. ABA level in the transgenic seedlings leaves was higher than those in the control plants under normal condition. Under exogenous ABA treatment and mannitol stress, the accumulation of ABA in the transgenic plants was higher than that in the control plants; while under salt stress, the difference of ABA content before treatment was gradually smaller with the prolongation of salt treatment time, then after 24 h of treatment the ABA level was similar in transgenic and wild-type plants. The transcription levels of several general stress marker genes (BnRD29A, BnERD15, and BnLEA1) were higher in the transgenic plants than the wild-type plants, whereas salt-responsive genes (BnSOS1, BnNHX1, and BnHKT) were not significantly different or even reduced compared with the wild-type plants, which indicated that BnSIP1-1 specifically exerted different regulatory mechanisms on the osmotic- and salt-response pathways in seedling period. Overall, these findings suggested that BnSIP1-1 played roles in ABA synthesis and signaling, salt and osmotic stress response. To date, information about the involvement of the Brassica napus trihelix gene in abiotic response is scarce

  7. PREFACE: Ultrathin layers of graphene, h-BN and other honeycomb structures Ultrathin layers of graphene, h-BN and other honeycomb structures

    Science.gov (United States)

    Geber, Thomas; Oshima, Chuhei

    2012-08-01

    Since ancient times, pure carbon materials have been familiar in human society—not only diamonds in jewellery and graphite in pencils, but also charcoal and coal which have been used for centuries as fuel for living and industry. Carbon fibers are stronger, tougher and lighter than steel and increase material efficiency because of their lower weight. Today, carbon fibers and related composite materials are used to make the frames of bicycles, cars and even airplane parts. The two-dimensional allotrope, now called graphene, is just a single layer of carbon atoms, locked together in a strongly bonded honeycomb lattice. In plane, graphene is stiffer than diamond, but out-of-plane it is soft, like rubber. It is virtually invisible, may conduct electricity (heat) better than copper and weighs next to nothing. Carbon compounds with two carbon atoms as a base, such as graphene, graphite or diamond, have isoelectronic sister compounds made of boron-nitrogen pairs: hexagonal and cubic boron nitride, with almost the same lattice constant. Although the two 2D sisters, graphene and h-BN, have the same number of valence electrons, their electronic properties are very different: freestanding h-BN is an insulator, while charge carriers in graphene are highly mobile. The past ten years have seen a great expansion in studies of single-layer and few-layer graphene. This activity has been concerned with the π electron transport in graphene, in electric and magnetic fields. More than 30 years ago, however, single-layer graphene and h-BN on solid surfaces were widely investigated. It was noted that they drastically changed the chemical reactivity of surfaces, and they were known to 'poison' heterogeneous catalysts, to passivate surfaces, to prevent oxidation of surfaces and to act as surfactants. Also, it was realized that the controlled growth of h-BN and graphene on substrates yields the formation of mismatch driven superstructures with peculiar template functionality on the

  8. Mid-IR Imaging of Orion BN/KL: Modeling of Physical Conditions and Energy Balance

    Science.gov (United States)

    Gezari, Daniel; Varosi, Frank; Dwek, Eli; Danchi, William C.; Tan, Jonathan; Okumura, Shin-ichiro

    2016-01-01

    We have modeled two mid-infrared imaging photometry data sets to determine the spatial distribution of physical conditions in the BN/KL (Becklin-Neugebauer / Kleinmann-Low) infrared complex. We observed the BN/KL region using the 10-meter Keck I telescope and the LWS (Living With a Star) in the direct imaging mode, over a 13 inch by 19 inch field . We also modeled images obtained with COMICS (Cooled Mid-Infrared Camera and Spectrometer, Kataza et al. 2000) at the 8.2-meter SUBARU telescope, over a total field of view [which] is 31 inches by 41 inches in a total of nine bands: 7.8, 8.8, 9.7, 10.5, 11.7, 12.4, 18.5, 20.8 and 24.8 microns with 1-micron bandwidth interference filters.

  9. Les collections cartographiques numérisées de la BnF

    Directory of Open Access Journals (Sweden)

    Olivier Loiseaux

    2005-04-01

    Full Text Available Depuis 1997 la Bibliothèque nationale de France (BnF propose en accès libre sur son site internet dans la rubrique Gallica de vastes collections de documents numérisés. Les fonds de Gallica, extraits de la vaste bibliothèque numérique de la BnF ont été choisis de manière à constituer une bibliothèque encyclopédique, centrée sur la culture francophone mais également pour permettre la découverte de ressources culturelles par le grand public. Ces fonds numérisés comprennent actuellement 70.000 ouvrages (21 millions de pages, 80.000 images et 500 documents sonores. Parmi les documents iconographiques, on recense entre 3500 et 4000 documents cartographiques.

  10. 2D Heterostructure coatings of hBN-MoS2 layers for corrosion resistance

    Science.gov (United States)

    Vandana, Sajith; Kochat, Vidya; Lee, Jonghoon; Varshney, Vikas; Yazdi, Sadegh; Shen, Jianfeng; Kosolwattana, Suppanat; Vinod, Soumya; Vajtai, Robert; Roy, Ajit K.; Sekhar Tiwary, Chandra; Ajayan, P. M.

    2017-02-01

    Heterostructures of atomically thin 2D materials could have improved physical, mechanical and chemical properties as compared to its individual components. Here we report, the effect of heterostructure coatings of hBN and MoS2 on the corrosion behavior as compared to coatings employing the individual 2D layer compositions. The poor corrosion resistance of MoS2 (widely used as wear resistant coating) can be improved by incorporating hBN sheets. Depending on the atomic stacking of the 2D sheets, we can further engineer the corrosion resistance properties of these coatings. A detailed spectroscopy and microscopy analysis has been used to characterize the different combinations of layered coatings. Detailed DFT based calculation reveals that the effect on the electrical properties due to atomic stacking is one of the major reasons for the improvement seen in corrosion resistance.

  11. Synthesis of boron-nitride nanocages and fullerenes in a BN plasma

    Science.gov (United States)

    Krstic, Predrag; Han, Longtao

    2016-09-01

    Synthesis of boron-nitride fullerenes, nano-cocoons and nano-cages by self-organization of BN molecules in a high-temperature plasma is simulated using the DFT tight-binding method. No boron nano-cluster or catalysts nano-particle are needed to initiate this process. By varying the plasma temperature and the BN density, as well as the time of growth we can simulate growth of he sp2 cages of various shape, size and quality. Role of hydrogen in HBNH and H2BNH2 synthesis is also considered. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

  12. Becoming Socialized into a New Professional Role: LPN to BN Student Nurses' Experiences with Legitimation

    Directory of Open Access Journals (Sweden)

    Sherri Melrose

    2012-01-01

    Full Text Available This paper presents findings from a qualitative descriptive study that explored the professional socialization experiences of Licensed Practical Nurses (LPNs who attended an online university to earn a Baccalaureate degree in nursing (BN, a prerequisite to writing the Canadian Registered Nurse (RN qualifying exam. The project was framed from a constructivist worldview and Haas and Shaffir’s theory of legitimation. Participants were 27 nurses in a Post-LPN to BN program who came from across Canada to complete required practicums. Data was collected from digital recordings of four focus groups held in different cities. Transcripts were analyzed for themes and confirmed with participants through member checking. Two overarching themes were identified and are presented to explain how these unique adult learners sought to legitimize their emerging identity as Registered Nurses (RNs. First, Post-LPN to BN students need little, if any, further legitimation to affirm their identities as “nurse.” Second, practicum interactions with instructors and new clinical experiences are key socializing agents.

  13. THE PROPER MOTIONS OF THE DOUBLE RADIO SOURCE n IN THE ORION BN/KL REGION

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Luis F.; Loinard, Laurent; Zapata, Luis; Lizano, Susana [Instituto de Radioastronomía y Astrofísica, UNAM, Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoacán, México (Mexico); Dzib, Sergio A.; Menten, Karl M. [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Gómez, Laura, E-mail: l.rodriguez@crya.unam.mx [Joint ALMA Observatory, Alonso de Córdoba 3107, Vitacura, Santiago (Chile)

    2017-01-10

    We have extended the time baseline for observations of the proper motions of radio sources in the Orion BN/KL region from 14.7 to 22.5 years. We present improved determinations for the sources BN and I. In addition, we address the proper motions of the double radio source n, that have been questioned in the literature. We confirm that all three sources are moving away at transverse velocities of tens of kilometers per second from a region in-between them, where they were located about 500 years ago. Source n exhibits a new component that we interpret as due to a one-sided ejection of free–free emitting plasma that took place after 2006.36. We used the highly accurate relative proper motions between sources BN and I to determine that their closest separation took place in the year 1475 ± 6, when they were within ∼100 au or less from each other in the plane of the sky.

  14. Mikroenkapsulasi Strain Probiotik Leuconostoc mesenteroides ssp. cremonis BN12 Menggunakan Berbagai Penyalut

    Directory of Open Access Journals (Sweden)

    Irma Hermana

    2015-12-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui karakteristik produk mikroenkapsulasi strain probiotik Leuconostoc mesenteroides ssp. cremonis BN12 menggunakan berbagai penyalut. Mikroenkapsulasi strain probiotik Leuconostoc mesenteroides ssp. cremonis BN12 dilakukan dengan teknik spray drying. Media mikroenkapsulasi berupa campuran dari penyalut (soluble fiber dengan larutan protein dan karbohidrat (skim milk, maltodekstrin dan glukosa. Adapun jenis-jenis penyalut yang digunakan adalah alginat 0,5%, xanthan gum 0,05% atau kitosan 0,5%.  Parameter yang diamati meliputi viabilitas sel probiotik sebelum dan setelah proses spray drying, ketahanan sel probiotik pada kondisi bile salt dan pH3 serta daya hambat sel probiotik setelah spray drying. Hasil penelitian menunjukkan bahwa penyalut terbaik untuk mikroenkapsulasi strain probiotik Leuconostoc mesenteroides ssp. cremonis BN12 adalah xanthan gum dengan viabilitas setelah spray drying mencapai 8,36 log cfu/g. Viabilitas sel pada media bile salt adalah 7,69 cfu/g dan pada pH 3 mencapai 2,7 log cfu/g setelah 24 jam masa inkubasi dengan daya hambat yang lebih baik terhadap patogen enterik Escherichia coli, Salmonella spp, Listeria monocytogenes dan Staphylococcus aureus.

  15. Superhydrophobic hBN-Regulated Sponges with Excellent Absorbency Fabricated Using a Green and Facile Method

    Science.gov (United States)

    Zhou, Ying; Wang, Yao; Liu, Tengfei; Xu, Gang; Chen, Guangming; Li, Huayi; Liu, Lichun; Zhuo, Qiqi; Zhang, Jiaoxia; Yan, Chao

    2017-03-01

    The world faces severe environmental, human and ecological problems when major oil spills and organic discharges are released into the environment. And so it is imperative to develop tools and high performance innovative materials that can efficiently absorb these organic discharges. Furthermore, green, facile methods to produce these advanced materials are also needed. In this paper, we demonstrate a novel porous supersponge based on melamine coated with hBN. This superhydrophobic sponge (with a contact angle >150°) exhibits excellent absorption performance for oils and organic solvents, including good selectivity, high capacity (up to 175 g·g-1) and extraordinary recyclability (less than 20% decline after 30 cycles of absorption/squeezing). The synthetic procedure required only ultrasonication and immersion of the sponge in aqueous hBN solution, being a green, cost-effective and scalable production methodology. By virtue of the straightforward and cost-effective fabrication method, along with the excellent absorption performance, hBN-decorated sponges have great promise for real world practical application in the field of oil spills and organic leakage cleanup.

  16. Conjugated π electron engineering of generalized stacking fault in graphene and h-BN

    Science.gov (United States)

    Ouyang, Bin; Chen, Cheng; Song, J.

    2018-03-01

    Generalized-stacking-fault energy (GSFE) serves as an important metric that prescribes dislocation behaviors in materials. In this paper, utilizing first-principle calculations and chemical bonding analysis, we studied the behaviors of generalized stacking fault in graphene and h-BN. It has been shown that the π bond formation plays a critical role in the existence of metastable stacking fault (MSF) in graphene and h-BN lattice along certain slip directions. Chemical functionalization was then proposed as an effective means to engineer the π bond, and subsequently MSF along dislocation slips within graphene and h-BN. Taking hydrogenation as a representative functionalization method, we demonstrated that, with the preferential adsorption of hydrogen along the slip line, π electrons along the slip would be saturated by adsorbed hydrogen atoms, leading to the moderation or elimination of MSF. Our study elucidates the atomic mechanism of MSF formation in graphene-like materials, and more generally, provides important insights towards predictive tuning of mechanic properties in two-dimensional nanomaterials.

  17. Investigation of bn-44 Peptide Fragments Using High Resolution Mass Spectrometry and Isotope Labeling

    Science.gov (United States)

    Wang, Bing; Yu, Jiayi; Wang, Huixin; Wei, Zhonglin; Guo, Xinhua; Xiao, Zhaohui; Zeng, Zhoufang; Kong, Wei

    2014-12-01

    An N-terminal deuterohemin-containing hexapeptide (DhHP-6) was designed as a short peptide cytochrome c (Cyt c) mimetic to study the effect of N-terminal charge on peptide fragmentation pathways. This peptide gave different dissociation patterns than normal tryptic peptides. Upon collision-induced dissociation (CID) with an ion trap mass spectrometer, the singly charged peptide ion containing no added proton generated abundant and characteristic bn-44 ions instead of bn-28 (an) ions. Studies by high resolution mass spectrometry (HRMS) and isotope labeling indicate that elimination of 44 Da fragments from b ions occurs via two different pathways: (1) loss of CH3CHO (44.0262) from a Thr side chain; (2) loss of CO2 (43.9898) from the oxazolone structure in the C-terminus. A series of analogues were designed and analyzed. The experimental results combined with Density Functional Theory (DFT) calculations on the proton affinity of the deuteroporphyrin demonstrate that the production of these novel bn-44 ions is related to the N-terminal charge via a charge-remote rather than radical-directed fragmentation pathway.

  18. Multifunctional tunneling devices based on graphene/h-BN/MoSe2 van der Waals heterostructures

    Science.gov (United States)

    Cheng, Ruiqing; Wang, Feng; Yin, Lei; Xu, Kai; Ahmed Shifa, Tofik; Wen, Yao; Zhan, Xueying; Li, Jie; Jiang, Chao; Wang, Zhenxing; He, Jun

    2017-04-01

    The vertically stacked devices based on van der Waals heterostructures (vdWHs) of two-dimensional layered materials (2DLMs) have attracted considerable attention due to their superb properties. As a typical structure, graphene/hexagonal boron nitride (h-BN)/graphene vdWH has been proved possible to make tunneling devices. Compared with graphene, transition metal dichalcogenides possess intrinsic bandgap, leading to high performance of electronic devices. Here, tunneling devices based on graphene/h-BN/MoSe2 vdWHs are designed for multiple functions. On the one hand, the device shows a typical tunneling field-effect transistor behavior. A high on/off ratio of tunneling current (5 × 103) and an ultrahigh current rectification ratio (7 × 105) are achieved, which are attributed to relatively small electronic affinity of MoSe2 and optimized thickness of h-BN. On the other hand, the same structure also realizes 2D non-volatile memory with a high program/erase current ratio (>105), large memory window (˜150 V from ±90 V), and good retention characteristic. These results could enhance the fundamental understanding of tunneling behavior in vdWHs and contribute to the design of ultrathin rectifiers and memory based on 2DLMs.

  19. Atomically precise semiconductor--graphene and hBN interfaces by Ge intercalation.

    Science.gov (United States)

    Verbitskiy, N I; Fedorov, A V; Profeta, G; Stroppa, A; Petaccia, L; Senkovskiy, B; Nefedov, A; Wöll, C; Usachov, D Yu; Vyalikh, D V; Yashina, L V; Eliseev, A A; Pichler, T; Grüneis, A

    2015-12-07

    The full exploration of the potential, which graphene offers to nanoelectronics requires its integration into semiconductor technology. So far the real-world applications are limited by the ability to concomitantly achieve large single-crystalline domains on dielectrics and semiconductors and to tailor the interfaces between them. Here we show a new direct bottom-up method for the fabrication of high-quality atomically precise interfaces between 2D materials, like graphene and hexagonal boron nitride (hBN), and classical semiconductor via Ge intercalation. Using angle-resolved photoemission spectroscopy and complementary DFT modelling we observed for the first time that epitaxially grown graphene with the Ge monolayer underneath demonstrates Dirac Fermions unaffected by the substrate as well as an unperturbed electronic band structure of hBN. This approach provides the intrinsic relativistic 2D electron gas towards integration in semiconductor technology. Hence, these new interfaces are a promising path for the integration of graphene and hBN into state-of-the-art semiconductor technology.

  20. Atomically precise semiconductor—graphene and hBN interfaces by Ge intercalation

    Science.gov (United States)

    Verbitskiy, N. I.; Fedorov, A. V.; Profeta, G.; Stroppa, A.; Petaccia, L.; Senkovskiy, B.; Nefedov, A.; Wöll, C.; Usachov, D. Yu.; Vyalikh, D. V.; Yashina, L. V.; Eliseev, A. A.; Pichler, T.; Grüneis, A.

    2015-01-01

    The full exploration of the potential, which graphene offers to nanoelectronics requires its integration into semiconductor technology. So far the real-world applications are limited by the ability to concomitantly achieve large single-crystalline domains on dielectrics and semiconductors and to tailor the interfaces between them. Here we show a new direct bottom-up method for the fabrication of high-quality atomically precise interfaces between 2D materials, like graphene and hexagonal boron nitride (hBN), and classical semiconductor via Ge intercalation. Using angle-resolved photoemission spectroscopy and complementary DFT modelling we observed for the first time that epitaxially grown graphene with the Ge monolayer underneath demonstrates Dirac Fermions unaffected by the substrate as well as an unperturbed electronic band structure of hBN. This approach provides the intrinsic relativistic 2D electron gas towards integration in semiconductor technology. Hence, these new interfaces are a promising path for the integration of graphene and hBN into state-of-the-art semiconductor technology. PMID:26639608

  1. High-performance polyimide nanocomposites with core-shell AgNWs@BN for electronic packagings

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yongcun; Liu, Feng, E-mail: liufeng@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an Shaanxi 710072 (China)

    2016-08-22

    The increasing density of electronic devices underscores the need for efficient thermal management. Silver nanowires (AgNWs), as one-dimensional nanostructures, possess a high aspect ratio and intrinsic thermal conductivity. However, high electrical conductivity of AgNWs limits their application for electronic packaging. We synthesized boron nitride-coated silver nanowires (AgNWs@BN) using a flexible and fast method followed by incorporation into synthetic polyimide (PI) for enhanced thermal conductivity and dielectric properties of nanocomposites. The thinner boron nitride intermediate nanolayer on AgNWs not only alleviated the mismatch between AgNWs and PI but also enhanced their interfacial interaction. Hence, the maximum thermal conductivity of an AgNWs@BN/PI composite with a filler loading up to 20% volume was increased to 4.33 W/m K, which is an enhancement by nearly 23.3 times compared with that of the PI matrix. The relative permittivity and dielectric loss were about 9.89 and 0.015 at 1 MHz, respectively. Compared with AgNWs@SiO{sub 2}/PI and Ag@BN/PI composites, boron nitride-coated core-shell structures effectively increased the thermal conductivity and reduced the permittivity of nanocomposites. The relative mechanism was studied and discussed. This study enables the identification of appropriate modifier fillers for polymer matrix nanocomposites.

  2. Time-resolved Polarimetry of the Superluminous SN 2015bn with the Nordic Optical Telescope

    DEFF Research Database (Denmark)

    Leloudas, Giorgos; Maund, Justyn R.; Gal-Yam, Avishay

    2017-01-01

    We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between -20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs of spectropol......We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between -20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs...... of spectropolarimetry are also available. Based on field stars, we determine the interstellar polarization in the Galaxy to be negligible. The polarization of SN 2015bn shows a statistically significant increase during the last epochs, confirming previous findings. Our well-sampled imaging polarimetry series allows us......, to a more aspherical inner core, dominated by freshly nucleosynthesized material. This two-layered model might account for the characteristic appearance and properties of Type I superluminous supernovae....

  3. Carbon-tuned bonding method significantly enhanced the hydrogen storage of BN-Li complexes.

    Science.gov (United States)

    Deng, Qing-ming; Zhao, Lina; Luo, You-hua; Zhang, Meng; Zhao, Li-xia; Zhao, Yuliang

    2011-11-01

    Through first-principles calculations, we found doping carbon atoms onto BN monolayers (BNC) could significantly strengthen the Li bond on this material. Unlike the weak bond strength between Li atoms and the pristine BN layer, it is observed that Li atoms are strongly hybridized and donate their electrons to the doped substrate, which is responsible for the enhanced binding energy. Li adsorbed on the BNC layer can serve as a high-capacity hydrogen storage medium, without forming clusters, which can be recycled at room temperature. Eight polarized H(2) molecules are attached to two Li atoms with an optimal binding energy of 0.16-0.28 eV/H(2), which results from the electrostatic interaction of the polarized charge of hydrogen molecules with the electric field induced by positive Li atoms. This practical carbon-tuned BN-Li complex can work as a very high-capacity hydrogen storage medium with a gravimetric density of hydrogen of 12.2 wt%, which is much higher than the gravimetric goal of 5.5 wt % hydrogen set by the U.S. Department of Energy for 2015.

  4. The Clar Structure in Inorganic BN Analogues of Polybenzenoid Hydrocarbons: Does it Exist or Not?

    Science.gov (United States)

    Wu, Jingjing; Zhu, Jun

    2015-12-21

    The Clar structure of polybenzenoid hydrocarbons (PBHs) have attracted considerable interest of both theoretical and experimental chemists since it was proposed in the 1950s. However, it remains unclear whether the Clar structure could exist in inorganic PBHs, the boron nitride (BN) analogues where the alternate boron and nitrogen atoms are used to replace the carbon atoms of PBHs. Here, we carry out thorough density functional theory (DFT) calculations to probe the possibility of Clar structures in BN analogues of PBHs. A strong correlation (r(2) =0.975) between the ring number (n=3-10) of BN analogues of [n]acenes and energy differences between the most and least stable isomers is identified, suggesting the existence of Clar structures in inorganic PBHs. In addition, the slightly weaker correlations in comparison to that (r(2) =0.989) of the organic PBHs is rationalized by the reduced aromaticity, which is revealed by two aromatic indices: ELFπ and SCI. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Microstructure Characteristics and Properties of HVOF Sprayed Ni-Based Alloy Nano-h-BN Self-Lubricating Composite Coatings

    Directory of Open Access Journals (Sweden)

    Xiaofeng Zhang

    2015-01-01

    Full Text Available A Ni-based alloy/nano-h-BN self-lubricating composite coating was produced on medium carbon steel by high velocity oxygen fuel (HVOF spraying technique. The powder feedstocks for HVOF spraying were prepared by ball milling and agglomerated the nano-h-BN with Ni-based alloy powders. The microstructure and mechanical properties of coatings have been investigated. With the increasing of h-BN contents, some delaminations appeared gradually in the coatings and a continuous network with h-BN phase embedded formed in the metallic matrix. The average microhardness of the self-lubricating coating was a little lower for the addition of soft solid lubricant. The friction coefficient of coatings is in the ranges of 0.38–0.48 and 0.38–0.52 at ambient temperature and 400°C, respectively. The maximum bonding strength of coatings reached 23.83 MPa.

  6. Investigation of dependence of BN-600 reactor sector fuel cladding leak detection system responses on the operation parameters

    Directory of Open Access Journals (Sweden)

    O.I. Albutova

    2015-12-01

    Implemented studies of dependence of background on the reactor operational parameters are of practical importance and are original scientifically - similar types of research have not been done previously. Upon completion of testing and validation of the developed model using extended volume of reactor operation data the issue will be addressed of the implementation of the methodology within the composition of the SFCLDS of BN-600 and BN-800 reactors.

  7. Low Temperature Noise Measurement of an InAs/GaSb-based nBn MWIR Detector

    Science.gov (United States)

    2011-01-01

    lack of fully passivated mesa sidewalls. An emerging infrared detector technology utilizing a unipolar, single-band barrier design, the so-called nBn ...Low Temperature Noise Measurement of an InAs/GaSb-based nBn MWIR Detector Vincent M. Cowan* 1 , Christian P. Morath 1 , Stephen Myers 2...2 Center for High Technology Materials, University of New Mexico, Albuquerque, NM 87106, USA ABSTRACT Recent experiments on conventional p-on-n

  8. Gamma-ray Irradiation Effects on InAs/GaSb-based nBn IR Detector

    Science.gov (United States)

    2011-01-01

    emerging detector architecture, complementary to SLS- technology and hence forth referred to here as nBn , mitigates this issue via a uni-polar barrier...Gamma-ray Irradiation Effects on InAs/GaSb-based nBn IR Detector Vincent M. Cowan*1, Christian P. Morath1, Seth M. Swift1, Stephen Myers2...2Center for High Technology Materials, University of New Mexico, Albuquerque, NM 87106, USA ABSTRACT IR detectors operated in a space environment are

  9. Reduction of azo dyes by redox mediators originating in the naphthalenesulfonic acid degradation pathway of Sphingomonas sp. strain BN6.

    Science.gov (United States)

    Keck, A; Klein, J; Kudlich, M; Stolz, A; Knackmuss, H J; Mattes, R

    1997-01-01

    The anaerobic reduction of azo dyes by Sphingomonas sp. strain BN6 was analyzed. Aerobic conversion of 2-naphthalenesulfonate (2NS) by cells of strain BN6 stimulated the subsequent anaerobic reduction of the sulfonated azo dye amaranth at least 10-fold. In contrast, in crude extracts, the azo reductase activity was not stimulated. A mutant of strain BN6 which was not able to metabolize 2NS showed increased amaranth reduction rates only when the cells were resuspended in the culture supernatant of 2NS-grown BN6 wild-type cells. The same increase could be observed with different bacterial strains. This suggested the presence of an extracellular factor which was formed during the degradation of 2NS by strain BN6. The addition of 1,2-dihydroxynaphthalene, the first intermediate of the degradation pathway of 2NS, or its decomposition products to cell suspensions of the mutant of strain BN6 (2NS-) increased the activity of amaranth reduction. The presence of bacterial cells was needed to maintain the reduction process. Thus, the decomposition products of 1,2-dihydroxynaphthalene are suggested to act as redox mediators which are able to anaerobically shuttle reduction equivalents from the cells to the extracellular azo dye. PMID:9293019

  10. Wear properties of hybrid ABO+BN+CNT/Al-Sn alloy matrix composites for engine bearing materials

    Science.gov (United States)

    Bak, Ji Hyeon; Cho, Dae Hyun; Shin, Sunmi; Park, Jin Young; Park, Ik Min

    2018-01-01

    Engine bearing materials need improved wear resistance to withstand high speeds and heavy loads. To meet the requirements of bearing materials, a new metal matrix composite (MMC) was designed. Here, the hybrid aluminum borate whisker (Al18B4O33, ABO) + hexagonal boron nitride (BN) + carbon nanotubes (CNTs)/Al-5Sn alloy MMCs were fabricated by squeeze infiltration. The wear properties of the hybrid MMCs were evaluated using a ball-on-disk tester. The effect of hybridization of ABO, BN, and CNTs on the wear properties of the Al-Sn MMCs was investigated. The microstructure of the hybrid MMCs showed a uniform distribution of the reinforcements. The wear resistance of the Al-5Sn alloy improved with the addition of ABO. The wear properties of the ABO+BN/ Al-Sn and ABO+CNT/Al-Sn MMCs were considerably enhanced compared to those of the ABO reinforced Al-Sn MMC because of the lubricating characteristic of BN and CNTs, and the CNTs were more effective than BN. The friction coefficient and wear rate of 20ABO+5BN+5CNT/Al-Sn MMC decreased by 1/4 and 1/20, respectively, compared to that of the ABO/Al-Sn MMC.

  11. Cyclosarin nerve agent interaction with the pristine, Stone Wales defected, and Si-doped BN nanosheets: Theoretical study

    Science.gov (United States)

    Nejati, K.; Arshadi, S.; Vessally, E.; Bekhradnia, A.; Hosseinian, A.

    2017-06-01

    Never agent identification and disposal is vital for both civilian and military defense resources. Herein, using density functional theory calculations, the reactivity and electronic sensitivity of pristine, Stone Wales (SW) defected, and Si-doped BN (Si-BN) nanosheets toward cyclosarin nerve agent were investigated. It was found that the interaction of cyclosarin with the pristine BN sheet is very weak and also that is not energetically favorable with SW defected one. Unlike the SW defect, replacing a B atom by Si atom significantly makes the cyclosarin adsorption energetically favorable. Calculations show that the carbonyl and etheric oxygen atoms of cyclosarin attack the Si atom of Si-BN with the adsorption energies of -73.5 and -136.9 kJ/mol, respectively. The cyclosarin nerve agent can be decomposed by the Si-BN sheet which is thermodynamically highly favorable. Upon this process, the HOMO and LUMO levels are significantly unstabilized and the HOMO-LUMO gap significantly changed by about 24.2%. The cyclosarin presence and its decomposition by Si-BN sheet can be recognized because of the electrical conductivity change of the sheet.

  12. Substitutional carbon doping of free-standing and Ru-supported BN sheets: a first-principles study

    Science.gov (United States)

    Berseneva, N.; Komsa, H.-P.; Vierimaa, V.; Björkman, T.; Fan, Z.; Harju, A.; Todorović, M.; Krasheninnikov, A. V.; Nieminen, R. M.

    2017-10-01

    The development of spatially homogeneous mixed structures with boron (B), nitrogen (N) and carbon (C) atoms arranged in a honeycomb lattice is highly desirable, as they open the possibility of creating stable two-dimensional materials with tunable band gaps. However, at least in the free-standing form, the mixed BCN system is energetically driven towards phase segregation to graphene and hexagonal BN. It is possible to overcome the segregation when BCN material is grown on a particular metal substrate, for example Ru(0 0 0 1), but the stabilization mechanism is still unknown. With the use of density-functional theory we study the energetics of BN/Ru slabs, with different types of configurations of C substitutional defects introduced to the h-BN overlayer. The results are compared to the energetics of free-standing BCN materials. We found that the substrate facilitates the C substitution process in the h-BN overlayer. Thus, more homogeneous BCN material can be grown, overcoming the segregation into graphene and h-BN. In addition, we investigate the electronic and transport gaps in free-standing BCN structures, and assess their mechanical properties and stability. The band gap in mixed BCN free-standing material depends on the concentration of the constituent elements and ranges from zero in pristine graphene to nearly 5 eV in free-standing h-BN. This makes BCN attractive for application in modern electronics.

  13. BN-350 unattended safeguards system current status and initial fuel movement data

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Richard Brady [Los Alamos National Laboratory; Browne, Michael C [Los Alamos National Laboratory; Parker, Robert F [Los Alamos National Laboratory; Ingegneri, Maurizio [IAEA

    2009-01-01

    The Unattended and Remote Monitoring (UNARM) system at the BN-350 fast breeder reactor facility in Aktau, Kazakhstan continues to provide safeguards monitoring data as the spent fuel disposition project transitions from wet fuel storage to dry storage casks. Qualitative data from the initial cask loading procedures has been released by the International Atomic Energy Agency (IAEA) and is presented here for the first time. The BN-350 fast breeder reactor in Aktau, Kazakhstan, operated as a plutonium-producing facility from 1973 W1til 1999. Kazakhstan signed the Nonproliferation Treaty (NPT) in February 1994, and shortly afterwards the IAEA began safeguarding the reactor facility and its nuclear material. Slnce the cessation of reactor operations ten years ago, the chief proliferation concern has been the spent fuel assemblies stored in the pond on-site. By 2002, all fuel assemblies in wet storage had been repackaged into proliferation-resistant canisters. From the beginning, the IAEA's safeguards campaign at the BN-350 included a constant unattended sensor presence in the form of UNARM which monitors nuclear material activities at the facility in the absence of inspector presence. The UNARM equipment at the BN-350 was designed to be modular and extensible, allowing the system to adapt as the safeguards requirements change. This has been particularly important at the BN-350 due to the prolonged wet storage phase of the project. The primary function of the BN-350 UNARM system is to provide the IAEA with an independent, radiation-centric Containment and Surveillance (C&S) layer in addition to the standard seals and video systems. The UNARM system has provided continuous Continuity of Knowledge (COK) data for the BN-350's nuclear material storage areas in order to ensure the validity of the attended measurements during the lifetime of the project. The first of these attended measurements was characterization of the spent fuel assemblies. This characterization

  14. Preparation of the radiopharmaceutical {sup 99m} Tc-HYNIC-[Lys{sup 3}]-BN; Preparacion del radiofarmaco {sup 99m} Tc-HYNIC-[Lys{sup 3}]-BN

    Energy Technology Data Exchange (ETDEWEB)

    Conde S, E. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico)

    2007-07-01

    In accordance with their design, the radiopharmaceuticals can be divided in three generations. The radiopharmaceuticals of third generation are used in nuclear medicine to obtain images of specific molecular targets, and they are only in their capacity to detect in vivo such specific biochemical places as receivers and enzymes. The receivers of regulator peptides are over expressed in numerous carcinogenic cells. Those receivers have been used as molecular targets of radiolabelled peptides to locate cancerous tumors. The small peptide bombesin (BN, 14 amino acids) it was isolated of the frog skin and it belongs to a wide neuropeptides group with many biological functions. The equivalent human is the liberator peptide of the gastrin (GRP, 27 amino acids) and his receivers (r-GRP) that are on expressed in the membranes of the tumor cells. The receiving subtype 2 of bombesin (receiving GRP) it is on expressed in several human tumors including breast, prostate, lung cells and pancreatic cancer. Some radiopharmaceuticals similar of BN has been developed that were prepared to be used in nuclear medicine for the detection of wicked tumors and to evidence prostate cancers, breast and of lymphatic nodules. A technique was developed to allow the conjugation of HYNIC-[Lys3]-BN that allowed to obtain this product with a high purity. The identity was determined by HPLC chromatography. It was necessary the validation of the method and the HPLC system, to assure that the results were reliable. Linearity, specificity, accuracy and precision parameters were analyzed, that are those required by the Mexican pharmacopoeia for chromatographic methods. With this conjugated a formulation for lyophilized kits were analyzed, with the purpose of obtaining a radiochemical purity, after the labelled one with {sup 99m}Tc, bigger to 95%; the components used in the nucleus-equipment should favor the conjugation of the {sup 99m}Tc by means of a ligands exchange between the tricine and the

  15. /sup 3/H-PAF-acether displacement and inhibition of binding in intact human platelets by BN 52021

    Energy Technology Data Exchange (ETDEWEB)

    Korth, R.; Le Couedic, J.P.; Benveniste, J.

    1986-03-05

    Intact washed human platelets incubated at 20/sup 0/C in Tyrode's buffer containing 0.25% (w/v) bovine serum albumin bound /sup 3/H paf-acether in a concentration (0-6.5 nM) and time (0-60 min) dependent manner (n=3). BN 52021 (60 ..mu..M) a chemically defined extract from Ginkgo biloba inhibited the binding of increasing concentrations of /sup 3/H paf-acether. Calculated differences between /sup 3/H paf-acether binding in the presence or absence of BN 52021 (60 ..mu..M) reached nearly a plateau in concentrations higher than 0.65 nM /sup 3/H paf-acether. Increasing concentrations of BN 52021 (0-60 ..mu..M) as well as of unlabelled paf-acether (0-50 nM) prevented within 15 min /sup 3/H paf-acether binding (0.65 nM) to platelets in a concentration-dependent way. Increasing BN 52021 concentrations (0-60 ..mu..M) also displaced platelet-bound /sup 3/H paf-acether (0.65 nM) in a concentration-dependent way. Displacement increased with the time length of platelet incubation with BN 52021 and reached a plateau at 15 min. Platelet-bound /sup 3/H paf-acether displacement of 28.3 +/- 6.3%, 31.1 +/- 4.0% and 26.7 +/- 5.6% was observed using 50 nM unlabelled paf-acether, 60 ..mu..M BN 52021 or both substances together (vs 4.3 +/- 7.2% for vehicle alone). No degradation of /sup 3/H paf-acether occurred as assessed by high pressure liquid chromatography. These results demonstrate that BN 52021 competes directly with paf-acether binding sites on human platelets.

  16. BN Dwivedi

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  17. Density functional theory study on structure and stability of BeBn+ clusters.

    Science.gov (United States)

    Liu, Chunhui; Si, Hongyan; Han, Peilin; Tang, Mingsheng

    2017-09-15

    Boride compounds hold promise for broad applications in the field of optoelectronics due to their high-temperature resistant, corrosion resistant and antioxidant properties. In order to reveal the formation mechanism of alkali and alkaline earth metal doped boron clusters, theoretical studies of these systems are required. All the possible geometrical structures of BeBn+ clusters (n = 1-8) were optimized at the B3LYP/6-311+G(d) level; the harmonic vibration frequencies were obtained to examine the true stability and give the zero-point vibration energy at that theoretical level. The single point energies of all the structures were computed at the CCSD(T)/aug-cc-pVDZ level. For the most stable structures, the average binding energy (Eb ), the fragmentation energy (EF ) and second-order difference of total energy (Δ2 E) were used to evaluate the relative stability of clusters. Most of the BeBn+ clusters are planar in structure; the B atoms tend to aggregate to form a boron ring, and the coordinating Be atoms are on the periphery of the clusters. The fragmentation energy and second-order difference of total energy show that there is an obvious odd-even alteration as n increases, and local-maxima when n is odd. A systematic theoretical investigation on the geometries, stabilities and electronic properties of BeBn+ clusters has been carried out where n = 1-8. The results provide a useful reference for understanding the formation mechanism and stability of these clusters, as well as guidance for finding larger size clusters. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Mechanical and Thermal Properties of Polymethyl Methacrylate-BN Nanotube Composites

    Directory of Open Access Journals (Sweden)

    C. Y. Zhi

    2008-01-01

    Full Text Available Polymethyl methacrylate (PMMA-BN nanotube (BNNT composites were fabricated and their mechanical and thermal properties were analyzed. Using a 1 wt.% BNNTs fraction in a polymer, the elastic modulus of PMMA was increased up to 19%. In addition, thermal stability and glass transition temperature of PMMA were also positively affected. The thermal conductivity of PMMA with BNNT additions increased three times. The resultant BNNT-PMMA composites possess the high electrical breakover voltages. Thus our studies clearly indicate that BNNTs are promising nanofillers for improvement of mechanical and thermal conductivity of dielectric polymers under preservation of their electrical insulation.

  19. Criticality safety issues in the disposition of BN-350 spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, R. W.; Klann, R. T.; Koltyshev, S. M.; Krechetov, S.

    2000-02-28

    A criticality safety analysis has been performed as part of the BN-350 spent fuel disposition project being conducted jointly by the DOE and Kazakhstan. The Kazakhstan regulations are reasonably consistent with those of the DOE. The high enrichment and severe undermoderation of this fast reactor fuel has significant criticality safety consequences. A detailed modeling approach was used that showed some configurations to be safe that otherwise would be rejected. Reasonable requirements for design and operations were needed, and with them, all operations were found to be safe.

  20. TPDA2 ALGORITHM FOR LEARNING BN STRUCTURE FROM MISSING VALUE AND OUTLIERS IN DATA MINING

    Directory of Open Access Journals (Sweden)

    Benhard Sitohang

    2006-01-01

    Full Text Available Three-Phase Dependency Analysis (TPDA algorithm was proved as most efficient algorithm (which requires at most O(N4 Conditional Independence (CI tests. By integrating TPDA with "node topological sort algorithm", it can be used to learn Bayesian Network (BN structure from missing value (named as TPDA1 algorithm. And then, outlier can be reduced by applying an "outlier detection & removal algorithm" as pre-processing for TPDA1. TPDA2 algorithm proposed consists of those ideas, outlier detection & removal, TPDA, and node topological sort node.

  1. Non-invasively improving the Schottky barriers of metal-MoS2 interfaces: effects of atomic vacancies in a BN buffer layer.

    Science.gov (United States)

    Su, Jie; Feng, Liping; Liu, Siyang; Liu, Zhengtang

    2017-08-09

    Using first-principles calculations within density functional theory, vacancies in the BN buffer layer have been predicted to improve the Schottky barrier of the metal-MoS2 interface without deteriorating the intrinsic properties of the MoS2 layer. Here, the effects of concentrations, sizes and types of vacancies on the contact properties of metal/BN-MoS2 sandwich interfaces are comparatively studied. The results show that vacancies in the BN buffer layer not only don't deteriorate the charge scatterings and electronic properties of the MoS2 layer at the metal/BN-MoS2 interface, but also improve the charge density and contact resistance between the metal surface and the BN layer. Although these vacancies have a negligible influence on the Fermi level pinning effect of the metal/BN-MoS2 interface, both N-vacancies and B-vacancies significantly change the position of the Fermi level of the metal/BN-MoS2 interface and then tune the Schottky barriers. Moreover, the Schottky barriers of metal/BN-MoS2 interfaces can decrease at first with the increasing concentrations and sizes of vacancies. When the concentration of vacancies increases to 4%, the Schottky barriers of metal/BN-MoS2 interfaces can reduce to the minimum value. The lowest n-type and p-type Schottky barriers of Au/BN-MoS2 and Pt/BN-MoS2 interfaces can reduce to -0.16 and 0.28 eV, respectively. However, the Schottky barriers are deteriorated when the sizes and concentrations of vacancies continue to increase because vacancies with large sizes and concentrations obviously change the interfacial structures of metal/BN-MoS2 interfaces and disarrange the directions of interface dipoles. The predictions in this work provide a non-invasive method to achieve high performance metal-MoS2 interfaces with low Schottky barriers.

  2. First-Principles Investigations of the Working Mechanism of 2D h-BN as an Interfacial Layer for the Anode of Lithium Metal Batteries.

    Science.gov (United States)

    Shi, Le; Xu, Ao; Zhao, Tianshou

    2017-01-18

    An issue with the use of metallic lithium as an anode material for lithium-based batteries is dendrite growth, causing a periodic breaking and repair of the solid electrolyte interphase (SEI) layer. Adding 2D atomic crystals, such as h-BN, as an interfacial layer between the lithium metal anode and liquid electrolyte has been demonstrated to be effective to mitigate dendrite growth, thereby enhancing the Columbic efficiency of lithium metal batteries. But the underlying mechanism leading to the reduced dendrite growth remains unknown. In this work, with the aid of first-principle calculations, we find that the interaction between the h-BN and lithium metal layers is a weak van der Waals force, and two atomic layers of h-BN are thick enough to block the electron tunneling from lithium metal to electrolyte, thus prohibiting the decomposition of electrolyte. The interlayer spacing between the h-BN and lithium metal layers can provide larger adsorption energies toward lithium atoms than that provided by bare lithium or h-BN, making lithium atoms prefer to intercalate under the cover of h-BN during the plating process. The combined high stiffness of h-BN and the low diffusion energy barriers of lithium at the Li/h-BN interfaces induce a uniform distribution of lithium under h-BN, therefore effectively suppressing dendrite growth.

  3. New Cu(TiBN x ) copper alloy films for industrial applications

    Science.gov (United States)

    Lin, Chon-Hsin

    2016-06-01

    In this study, I explore a new type of copper alloy, Cu(TiBN x ), films by cosputtering Cu and TiB within an Ar/N2 gas atmosphere on Si substrates. The films are then annealed for 1 h in a vacuum environment at temperatures up to 700 °C. The annealed films exhibit not only excellent thermal stability and low resistivity but also little leakage current and strong adhesion to the substrates while no Cu/Si interfacial interactions are apparent. Within a Sn/Cu(TiBN x )/Si structure at 200 °C, the new alloy exhibits a minute dissolution rate, which is lower than that of pure Cu by at least one order of magnitude. Furthermore, the new alloy’s consumption rate is comparable to that of Ni commonly used in solder joints. The new films appear suitable for some industrial applications, such as barrierless Si metallization and new wetting and diffusion barrier layers required in flip-chip solder joints.

  4. Controlled Electrochemical Intercalation of Graphene/h-BN van der Waals Heterostructures

    Science.gov (United States)

    Zhao, S. Y. Frank; Elbaz, Giselle A.; Bediako, D. Kwabena; Yu, Cyndia; Efetov, Dmitri K.; Guo, Yinsheng; Ravichandran, Jayakanth; Min, Kyung-Ah; Hong, Suklyun; Taniguchi, Takashi; Watanabe, Kenji; Brus, Louis E.; Roy, Xavier; Kim, Philip

    2018-01-01

    Electrochemical intercalation is a powerful method for tuning the electronic properties of layered solids. In this work, we report an electro-chemical strategy to controllably intercalate lithium ions into a series of van der Waals (vdW) heterostructures built by sandwiching graphene between hexagonal boron nitride (h-BN). We demonstrate that encapsulating graphene with h-BN eliminates parasitic surface side reactions while simultaneously creating a new hetero-interface that permits intercalation between the atomically thin layers. To monitor the electrochemical process, we employ the Hall effect to precisely monitor the intercalation reaction. We also simultaneously probe the spectroscopic and electrical transport properties of the resulting intercalation compounds at different stages of intercalation. We achieve the highest carrier density $> 5 \\times 10^{13} cm^{-2}$ with mobility $> 10^3 cm^2/(Vs)$ in the most heavily intercalated samples, where Shubnikov-de Haas quantum oscillations are observed at low temperatures. These results set the stage for further studies that employ intercalation in modifying properties of vdW heterostructures.

  5. Dynamic Negative Compressibility of Few-Layer Graphene, h-BN, and MoS2

    Science.gov (United States)

    Neves, Bernardo; Barboza, Ana Paula; Chacham, Helio; Oliveira, Camilla; Fernandes, Thales; Martins Ferreira, Erlon; Archanjo, Braulio; Batista, Ronaldo; Oliveira, Alan

    2013-03-01

    We report a novel mechanical response of few-layer graphene, h-BN, and MoS2 to the simultaneous compression and shear by an atomic force microscope (AFM) tip. The response is characterized by the vertical expansion of these two-dimensional (2D) layered materials upon compression. Such effect is proportional to the applied load, leading to vertical strain values (opposite to the applied force) of up to 150%. The effect is null in the absence of shear, increases with tip velocity, and is anisotropic. It also has similar magnitudes in these solid lubricant materials (few-layer graphene, h-BN, and MoS2), but it is absent in single-layer graphene and in few-layer mica and Bi2Se3. We propose a physical mechanism for the effect where the combined compressive and shear stresses from the tip induce dynamical wrinkling on the upper material layers, leading to the observed flake thickening. The new effect (and, therefore, the proposed wrinkling) is reversible in the three materials where it is observed.[2] Financial support from CNPq, Fapemig, Rede Nacional de Pesquisa em Nanotubos de Carbono and INCT-Nano-Carbono

  6. Creep/Stress Rupture Behavior of 3D Woven SiC/SiC Composites with Sylramic-iBN, Super Sylramic-iBN and Hi-Nicalon-S Fibers at 2700F in Air

    Science.gov (United States)

    Bhatt, R. T.

    2017-01-01

    To determine the influence of fiber types on creep durability, 3D SiC/SiC CMCs were fabricated with Sylramic-iBN, super Sylramic-iBN and Hi-Nicalon-S fibers and the composite specimens were then tested under isothermal tensile creep at 14820C at 69, 103 and 138 MPa for up to 300hrs in air. The failed specimens were examined by scanning electron microscopy (SEM) and computed tomography (CT) for fracture mode analysis. The creep data of these composites are compared with those of other SiC/SiC composites in the literature. The results of this study will be presented.

  7. 111In-BnDTPA-F3: an Auger electron-emitting radiotherapeutic agent that targets nucleolin.

    Science.gov (United States)

    Cornelissen, Bart; Waller, Andrew; Target, Carol; Kersemans, Veerle; Smart, Sean; Vallis, Katherine A

    2012-02-20

    The F3 peptide (KDEPQRRSARLSAKPAPPKPEPKPKKAPAKK), a fragment of the human high mobility group protein 2, binds nucleolin. Nucleolin is expressed in the nuclei of normal cells but is also expressed on the membrane of some cancer cells. The goal was to investigate the use of 111In-labeled F3 peptide for Auger electron-targeted radiotherapy. F3 was labeled with fluorescein isothiocyanate (FITC) for confocal microscopy and conjugated to p-SCN-benzyl-diethylenetriaminepentaacetic acid (BnDTPA) for labeling with 111In to form 111In-BnDTPA-F3. MDA-MB-231-H2N (231-H2N) human breast cancer cells were exposed to 111In-BnDTPA-F3 and used in cell fractionation, γH2AX immunostaining (a marker of DNA double-strand breaks), and clonogenic assays. In vivo, biodistribution studies of 111In-BnDTPA-F3 were performed in 231-H2N xenograft-bearing mice. In tumor growth delay studies, 111In-BnDTPA-F3 (3 μg, 6 MBq/μg) was administered intravenously to 231-H2N xenograft-bearing mice once weekly for 3 weeks. Membrane-binding of FITC-F3 was observed in 231-H2N cells, and there was co-localization of FITC-F3 with nucleolin in the nuclei. After exposure of 231-H2N cells to 111In-BnDTPA-F3 for 2 h, 1.7% of 111In added to the medium was membrane-bound. Of the bound 111In, 15% was internalized, and of this, 37% was localized in the nucleus. Exposure of 231-H2N cells to 111In-BnDTPA-F3 (1 μM, 6 MBq/μg) resulted in a dose-dependent increase in γH2AX foci and in a significant reduction of clonogenic survival compared to untreated cells or cells exposed to unlabeled BnDTPA-F3 (46 ± 4.1%, 100 ± 1.8%, and 132 ± 7.7%, respectively). In vivo, tumor uptake of 111In-BnDTPA-F3 (3 μg, 6 MBq/μg) at 3-h post-injection was 1% of the injected dose per gram (%ID/g), and muscle uptake was 0.5%ID/g. In tumor growth delay studies, tumor growth rate was reduced 19-fold compared to untreated or unlabeled BnDTPA-F3-treated mice (p = 0.023). 111In-BnDTPA-F3 is internalized into 231-H2N cells and translocates

  8. Al-doped graphene-like BN nanosheet as a sensor for para-nitrophenol: DFT study

    Science.gov (United States)

    Peyghan, Ali Ahmadi; Noei, Maziar; Yourdkhani, Sirous

    2013-07-01

    We investigated the electronic sensitivity of pristine and Al-doped BN sheets to para-nitrophenol (p-NP) by using density functional calculations. It was found that p-NP adsorption on the pristine sheet is endothermic and unfavorable. By replacing adsorbing boron atom of the sheet surface by an Al atom, the sheet becomes more reactive to p-NP, so energy of 20.4 kcal/mol is released upon adsorption process. Upon p-NP adsorption on the Al-doped BN sheet, HOMO/LUMO energy gap of the sheet is dramatically decreased from 5.39 to 1.23 eV and it becomes a p-type semiconductor. Thus, the Al-doped BN sheet may transform the presence of p-NP molecule into an electrical signal, and it might be potentially used in p-NP sensors.

  9. Boosting the adsorption performance of BN nanosheet as an anode of Na-ion batteries: DFT studies

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinian, A. [Department of Engineering Science, College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of); Soleimani-amiri, S. [Department of Chemistry, Karaj Branch, Islamic Azad University, Karaj (Iran, Islamic Republic of); Arshadi, S., E-mail: chemistry_arshadi@pnu.ac.ir [Department of Chemistry, Payame Noor University, Tehran (Iran, Islamic Republic of); Vessally, E. [Department of Chemistry, Payame Noor University, Tehran (Iran, Islamic Republic of); Edjlali, L. [Department of Chemistry, Tabriz Branch, Islamic Azad University, Tabriz (Iran, Islamic Republic of)

    2017-06-28

    Despite the high advance in the Li-ion battery technology, there exist great concerns about its lifetime, safety, cost, and low-temperature performance. It is expected that the Li-ion batteries may be replaced by Na-ion batteries (NIB) because of the low cost, nontoxicity, and wide availability of sodium. Here, we investigated the potential application of BN nanosheets in anode of NIBs by means of density functional theory calculation and introduced a strategy to increase their performance. It was shown that the Na and Na{sup +} are mainly adsorbed on the center of a hexagonal ring of BN sheet with adsorption energies of −0.08 and −33.7 kcal/mol, respectively. Replacing three N atoms of the hexagonal ring with larger P atoms significantly increases the performance of the sheet as an anode of a NIB but the replacement of B by Al decreases the performance. The initial cell voltage of LIB is increased by about 0.67 V after the P-doping which causes a high storage performance with long discharge time. The results are discussed based on the energetic, structural, orbital, charge transfer and electronic properties and provide guidelines to build better high-capacity anode materials for NIBs. - Highlights: • Potential use of BN sheet as anode in Na-ion batteries (NIB) is studied by DFT. • The replacement of B by Al decreases the performance. • The cell voltage of LIB is increased by about 0.67 V after by P-doping. • The order of performance is P-BN > BN >> Al-BN.

  10. Molecular Cloning, Recombinant Expression and Antifungal Activity of BnCPI, a Cystatin in Ramie (Boehmeria nivea L.

    Directory of Open Access Journals (Sweden)

    Yongting Yu

    2017-10-01

    Full Text Available Phytocystatins play multiple roles in plant growth, development and resistance to pests and other environmental stresses. A ramie (Boehmeria nivea L. phytocystatin gene, designated as BnCPI, was isolated from a ramie cDNA library and its full-length cDNA was obtained by rapid amplification of cDNA ends (RACE. The full-length cDNA sequence (691 bp consisted of a 303 bp open reading frame (ORF encoding a protein of 100 amino acids with deduced molecular mass of 11.06 kDa and a theoretical isoelectric point (pI of 6.0. The alignment of genome DNA (accession no. MF153097 and cDNA sequences of BnCPI showed that an intron (~104 bp exists in the coding region. The BnCPI protein contains most of the highly conserved blocks including Gly5-Gly6 at the N-terminal, the reactive site motif QxVxG (Q49V50V51S52G53, the L79-W80 block and the [LVI]-[AGT]-[RKE]-[FY]-[AS]-[VI]-x-[EDQV]-[HYFQ]-N (L22G23R24 F25A26V27 D28D29H30 N31 block that is common among plant cystatins. BLAST analysis indicated that BnCPI is similar to cystatins from Glycine max (77%, Glycine soja (76%, Hevea brasiliensis (75% and Ricinus communis (75%. The BnCPI was subcloned into expression vector pSmart-I and then overexpressed in Escherichia coli BL21 (DE3 as a His-tagged recombinant protein. The purified reBnCPI has a molecular mass of 11.4 kDa determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE. Purified reBnCPI can efficiently inhibit the protease activity of papain and ficin toward BANA (Nα-benzoyl-L-arginine-2-naphthyamide, as well as the mycelium growth of some important plant pathogenic fungi. The data further contribute to our understanding of the molecular functions of BnCPI.

  11. Investigation of band structure and electrochemical properties of h-BN/rGO composites for asymmetric supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sanjit; Jana, Milan; Samanta, Pranab; Murmu, Naresh C. [Surface Engineering & Tribology Division, CSIR-Central Mechanical Engineering Research Institute, Durgapur, 713209 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-CMERI Campus, Durgapur, 713209 (India); Kim, Nam H. [Advanced Materials Institute of BIN Convergence Technology (BK21 Plus Global), Dept. of BIN Convergence Technology, Chonbuk National University, Jeonju, Jeonbuk, 54896 (Korea, Republic of); Kuila, Tapas, E-mail: tkuila@gmail.com [Surface Engineering & Tribology Division, CSIR-Central Mechanical Engineering Research Institute, Durgapur, 713209 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-CMERI Campus, Durgapur, 713209 (India); Lee, Joong H., E-mail: jhl@jbnu.ac.kr [Advanced Materials Institute of BIN Convergence Technology (BK21 Plus Global), Dept. of BIN Convergence Technology, Chonbuk National University, Jeonju, Jeonbuk, 54896 (Korea, Republic of); Carbon Composite Research Centre, Department of Polymer & Nanoscience and Technology, Chonbuk National University, Jeonju, Jeonbuk, 54896 (Korea, Republic of)

    2017-04-01

    The effect of different content of graphene oxide (GO) on the electrical and electrochemical property of h-BN/reduced GO (rGO) hetero-structure is investigated elaborately. The increasing amount of rGO within the h-BN moiety plays fascinating role by reducing the electronic work function while increasing the density of state of the electrode. Furthermore, different h-BN/rGO architecture shows different potential window and the transition from pseudocapacitance to electrochemical double layer capacitance (EDLC) is observed with increasing π-conjugation of C atoms. The rod like h-BN is aligned as sheet while forming super-lattice with rGO. Transmission electron microscopy images show crystalline morphology of the hetero-structure super-lattice. The valance band and Mott-Shotky relationship determined from Mott-Shotky X-ray photoelectron spectroscopy shows that the electronic band structure of super-lattice is improved as compared to the insulating h-BN. The h-BN/rGO super-lattice provides high specific capacitance of ∼960 F g{sup −1}. An asymmetric device configured with h-BN/rGO super-lattice and B, N doped rGO shows very high energy and power density of 73 W h kg{sup −1} and 14,000 W kg{sup −1}, respectively. Furthermore, very low relaxation time constant of ∼1.6 ms and high stability (∼80%) after 10,000 charge-discharge cycles ensure the h-BN/rGO super-lattice as potential materials for the next generation energy storage applications. - Highlights: • Band gap energy of boron nitride decreased with increasing graphene oxide content. • Graphene oxide effectively affected the charge storage mechanism of the composite. • Morphology of boron nitride changed from rod to sheet while forming superlattice. • Highly conducting superlattice showed excellent supercapacitor performance. • Asymmetric device exhibited long stability with high energy and power density.

  12. Electronic structure of BN-aromatics: Choice of reliable computational tools

    Science.gov (United States)

    Mazière, Audrey; Chrostowska, Anna; Darrigan, Clovis; Dargelos, Alain; Graciaa, Alain; Chermette, Henry

    2017-10-01

    The importance of having reliable calculation tools to interpret and predict the electronic properties of BN-aromatics is directly linked to the growing interest for these very promising new systems in the field of materials science, biomedical research, or energy sustainability. Ionization energy (IE) is one of the most important parameters to approach the electronic structure of molecules. It can be theoretically estimated, but in order to evaluate their persistence and propose the most reliable tools for the evaluation of different electronic properties of existent or only imagined BN-containing compounds, we took as reference experimental values of ionization energies provided by ultra-violet photoelectron spectroscopy (UV-PES) in gas phase—the only technique giving access to the energy levels of filled molecular orbitals. Thus, a set of 21 aromatic molecules containing B-N bonds and B-N-B patterns has been merged for a comparison between experimental IEs obtained by UV-PES and various theoretical approaches for their estimation. Time-Dependent Density Functional Theory (TD-DFT) methods using B3LYP and long-range corrected CAM-B3LYP functionals are used, combined with the Δ SCF approach, and compared with electron propagator theory such as outer valence Green's function (OVGF, P3) and symmetry adapted cluster-configuration interaction ab initio methods. Direct Kohn-Sham estimation and "corrected" Kohn-Sham estimation are also given. The deviation between experimental and theoretical values is computed for each molecule, and a statistical study is performed over the average and the root mean square for the whole set and sub-sets of molecules. It is shown that (i) Δ SCF+TDDFT(CAM-B3LYP), OVGF, and P3 are the most efficient way for a good agreement with UV-PES values, (ii) a CAM-B3LYP range-separated hybrid functional is significantly better than B3LYP for the purpose, especially for extended conjugated systems, and (iii) the "corrected" Kohn-Sham result is a

  13. First-principles studies of BN sheets with absorbed transition metal single atoms or dimers: stabilities, electronic structures, and magnetic properties.

    Science.gov (United States)

    Ma, Dongwei; Lu, Zhansheng; Ju, Weiwei; Tang, Yanan

    2012-04-11

    BN sheets with absorbed transition metal (TM) single atoms, including Fe, Co, and Ni, and their dimers have been investigated by using a first-principles method within the generalized gradient approximation. All of the TM atoms studied are found to be chemically adsorbed on BN sheets. Upon adsorption, the binding energies of the Fe and Co single atoms are modest and almost independent of the adsorption sites, indicating the high mobility of the adatoms and isolated particles to be easily formed on the surface. However, Ni atoms are found to bind tightly to BN sheets and may adopt a layer-by-layer growth mode. The Fe, Co, and Ni dimers tend to lie (nearly) perpendicular to the BN plane. Due to the wide band gap of the pure BN sheet, the electronic structures of the BN sheets with TM adatoms are determined primarily by the distribution of TM electronic states around the Fermi level. Very interesting spin gapless semiconductors or half-metals can be obtained in the studied systems. The magnetism of the TM atoms is preserved well on the BN sheet, very close to that of the corresponding free atoms and often weakly dependent on the adsorption sites. The present results indicate that BN sheets with adsorbed TM atoms have potential applications in fields such as spintronics and magnetic data storage due to the special spin-polarized electronic structures and magnetic properties they possess.

  14. Calpain inhibitors and antioxidants act synergistically to prevent cell necrosis: effects of the novel dual inhibitors (cysteine protease inhibitor and antioxidant) BN 82204 and its pro-drug BN 82270.

    Science.gov (United States)

    Pignol, Bernadette; Auvin, Serge; Carré, Denis; Marin, Jean-Grégoire; Chabrier, Pierre-Etienne

    2006-08-01

    Cell death is a common feature observed in neurodegenerative disorders, and is often associated with calpain activation and overproduction of reactive oxygen species (ROS). This study investigated the use of calpain inhibitors and antioxidants in combination to protect cells against necrosis. Maitotoxin (MTX), which induces a massive influx of calcium, was used to provoke neuronal cell death. This toxin increased, in a concentration-dependent manner, both calpain activity and ROS formation. Calpain inhibitors or antioxidants inhibited MTX-induced necrosis only marginally (below 20%), whereas their association protected against cell death by 40-66% in a synergistic manner. BN 82204, which possesses both calpain-cathepsin L inhibitory and antioxidant properties, and its acetylated pro-drug BN 82270, totally protected cells at 100 microm. The pro-drug BN 82270, which had better cell penetration, was twice as effective as the active principle BN 82204 in protecting glioma C6 or neuroblastoma SHSY5Y cells against death. These results suggest the potential therapeutic relevance of using a single molecule with multiple activities (cysteine protease inhibitor/antioxidant), and warrant further in vivo investigations in models of neuronal disorders.

  15. Deposition of BN thin films onto Si(1 0 0) substrate by PLD with nanosecond and femtosecond pulses in nitrogen gas background

    Science.gov (United States)

    Luculescu, C. R.; Miyake, H.; Sato, S.

    2002-09-01

    BN thin films were deposited using pulsed laser deposition (PLD) by irradiating a hot-pressed h-BN target with a fourth harmonic wave of a Nd:YAG laser and a fundamental wave of a Ti:Sapphire laser in a background of nitrogen gas atmosphere without any aid of energetic techniques. Si(1 0 0) wafers with smooth and chemically etched surface were used as substrates. The films were characterized by SEM, XPS and FTIR. It was found that the cubic phase is present only in BN films deposited with UV nanosecond pulses. The absence of cubic phase in BN films deposited by femtosecond ablation is supposed to be due to high laser irradiance which causes the removal of unevaporated material from a soft target such as h-BN.

  16. Deposition of BN thin films onto Si(1 0 0) substrate by PLD with nanosecond and femtosecond pulses in nitrogen gas background

    Energy Technology Data Exchange (ETDEWEB)

    Luculescu, C.R.; Miyake, H.; Sato, S

    2002-09-30

    BN thin films were deposited using pulsed laser deposition (PLD) by irradiating a hot-pressed h-BN target with a fourth harmonic wave of a Nd:YAG laser a fundamental wave of a Ti:Sapphire laser in a background of nitrogen gas atmosphere without any aid of energetic techniques. Si(1 0 0) wafers with smooth and chemically etched surface were used as substrates. The films were characterized by SEM, XPS and FTIR. It was found that the cubic phase is present only in BN films deposited with UV nanosecond pulses. The absence of cubic phase in BN films deposited by femtosecond ablation is supposed to be due to high laser irradiance which causes the removal of unevaporated material from a soft target such as h-BN.

  17. Tuning Electronic Structures of BN and C Double-Wall Hetero-Nanotubes

    Directory of Open Access Journals (Sweden)

    Xueran Liu

    2015-01-01

    Full Text Available First principle calculations based on density functional theory with the generalized gradient approximation were carried out to investigate the energetic and electronic properties of carbon and boron nitride double-wall hetero-nanotubes (C/BN-DWHNTs with different chirality and size, including an armchair (n, n carbon nanotube (CNT enclosed in (m, m boron nitride nanotube (BNNT and a zigzag (n, 0 CNT enclosed in (m, 0 BNNT. The electronic structure of these DWHNTs under a transverse electric field was also investigated. The ability to tune the band gap with changing the intertube distance (di and imposing an external electric field (F of zigzag DWHNTs provides the possibility for future electronic and electrooptic nanodevice applications.

  18. Sessional teachers in a BN program: bridging the divide or widening the gap?

    Science.gov (United States)

    Andrew, Sharon; Halcomb, Elizabeth J; Jackson, Debra; Peters, Kath; Salamonson, Yenna

    2010-07-01

    Casualisation of the academic workforce has resulted in an increase in the employment of sessional teachers in Bachelor of Nursing (BN) programs. Many of these teachers are drawn from specialty clinical areas and continue to work clinically while teaching part-time. The aim of this study was to explore the perceptions of sessional teachers about their perceived contribution to an undergraduate Bachelor of Nursing program in a single Australian university. Twelve sessional teachers participated in semi-structured interviews as part of a larger mixed method study exploring the issues related to sessional teaching in the Bachelor of Nursing program. Three themes emerged from the data; (1) "Bringing 'reality' to the classroom", (2) "Privileging experiential knowledge", and (3) "Establishing boundaries with students". Underpinning the narratives was a strong subtext related to the theory-practice gap. Proactive strategies to facilitate the potential of sessional staff are articulated in the paper. Copyright 2009 Elsevier Ltd. All rights reserved.

  19. Modeling of BN Lifetime Prediction of a System Based on Integrated Multi-Level Information.

    Science.gov (United States)

    Wang, Jingbin; Wang, Xiaohong; Wang, Lizhi

    2017-09-15

    Predicting system lifetime is important to ensure safe and reliable operation of products, which requires integrated modeling based on multi-level, multi-sensor information. However, lifetime characteristics of equipment in a system are different and failure mechanisms are inter-coupled, which leads to complex logical correlations and the lack of a uniform lifetime measure. Based on a Bayesian network (BN), a lifetime prediction method for systems that combine multi-level sensor information is proposed. The method considers the correlation between accidental failures and degradation failure mechanisms, and achieves system modeling and lifetime prediction under complex logic correlations. This method is applied in the lifetime prediction of a multi-level solar-powered unmanned system, and the predicted results can provide guidance for the improvement of system reliability and for the maintenance and protection of the system.

  20. N2 activation on Al metal clusters: catalyzing role of BN-doped graphene support.

    Science.gov (United States)

    Kumar, Deepak; Pal, Sourav; Krishnamurty, Sailaja

    2016-10-12

    The successful sustenance of life demands an ambient abiotic process for N2 activation and dissociation. The Bosch-Haber process remains the only abiotic and synthetic means for N2 activation and its fixation. Metal nanoclusters have been recently reported for activating molecular nitrogen. Interestingly, the metal clusters explored so far for N2 activation are free clusters and, hence, are practically not applicable by experimental chemists. Using density functional theory (DFT) based methodology, we propose a potential catalytic system for di-nitrogen activation, viz. supported Al clusters. Al clusters supported on BN doped graphene sheets are seen to activate N2 molecule with a red shift in the N-N stretching frequency up to 874 cm(-1) with activation barriers as low as 1.14 eV.

  1. Magnetic, electronic and optical properties of different graphene, BN and BC2N nanoribbons

    Science.gov (United States)

    Guerra, T.; Leite, L.; Azevedo, S.; de Lima Bernardo, B.

    2017-04-01

    Graphene nanoribbons are predicted to be essential components in future nanoelectronics. The size, edge type, form, arrangement of atoms and width of nanoribbons drastically change their properties. However, magnetic, electronic and optical properties of armchair, chevron and sawtooth of graphene, BN and BC2N nanoribbons are not fully understood so far. Here, we make use of first-principles calculations based on the density functional theory (DFT) to investigate the structural, magnetic, electronic and optical properties of nanoribbons of graphene, boron nitride and BC2N with armchair edge, chevron-type and sawtooth forms. The lowest formation energies were found for the armchair and chevron nanoribbons of graphene and boron nitride. We have shown that the imbalance of carbon atoms between different sublattices generates a net magnetic moment. Chevron-type nanoribbons of BC2N and graphene showed a band gap comparable with silicon, and a high light absorption in the visible spectrum when compared to the other configurations.

  2. Effects of nano-sized boron nitride (BN) reinforcement in expandable graphite based in-tumescent fire retardant coating

    Science.gov (United States)

    Zulkurnain, E. S.; Ahmad, F.; Gillani, Q. F.

    2016-08-01

    The purpose of in-tumescent fire retardant coating (IFRC) is to protect substrate from fire attack by limiting heat transfer. A range of coating formulations have been prepared using Bisphenol A epoxy resin BE-188 and polyamide solidifier H-2310 as two-part binder, ammonium polyphosphate (APP) as acid source, melamine (MEL) as the blowing agent, expandable graphite (EG) as carbon source and nano-boron nitride (BN) as inorganic nano filler. The filler was used to improve the performances of the APP-EG-MEL coating. The effects of nano-BN on the char morphology and thermal degradation were investigated by fire test, thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X- ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FESEM). The results showed that by substituting or reinforcing of 4% weight percentage of nano-BN, residual weight of the char increases by 23.82% compared to APP-EG-MEL coating without filler. Higher carbon content was obtained in the char and a more compact char was produced. The results indicated that nano-BN could be used as a filler to improve thermal stability of the APP-EG-MEL coating.

  3. A simple thermal decomposition-nitridation route to nanocrystalline boron nitride (BN) from a single N and B source precursor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hong; Chen Youjian [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325027 (China); Ma Jianhua, E-mail: mjh820@ustc.edu [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325027 (China); Nanomaterials and Chemistry Key Laboratory, Advanced Materials Research Center of Wenzhou, Wenzhou University, Wenzhou, Zhejiang 325027 (China); Tong Hanxuan; Yang Jiang; Ni Danwei; Hu Huiming; Zheng Fangqing [Oujiang College, Wenzhou University, Wenzhou, Zhejiang 325027 (China)

    2011-06-09

    Graphical abstract: Display Omitted Highlights: > Nanocrystalline BN was synthesized via a thermal decomposition-nitridation route. > B and N sources come from a single cheap safe precursor NH{sub 4}HB{sub 4}O{sub 7}.3H{sub 2}O. > The reaction could be carried out in an autoclave at 650 deg. C for 8 h. > X-ray powder diffraction patterns indicate that the product is hexagonal BN. > The product has good thermal stability and oxidation resistance below 900 deg. C. - Abstract: Nanocrystalline boron nitride (BN) was synthesized via a simple thermal decomposition-nitridation route by the reaction of hydrated ammonium tetraborate (NH{sub 4}HB{sub 4}O{sub 7}.3H{sub 2}O) and metallic magnesium powders in an autoclave at 650 deg. C. The crystal phase, morphology, grain size, and chemical composition of the as-prepared products were characterized in detail by X-ray powder diffraction (XRD), energy dispersion spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The products were also studied by FT-IR and the thermogravimetric analysis (TGA). Results revealed that the as-synthesized nanocrystalline were h-BN, and they had diameters within 100 nm. They had good thermal stability and oxidation resistance in high temperature.

  4. Acetone in Orion BN/KL: High-resolution maps of a special oxygen-bearing molecule

    National Research Council Canada - National Science Library

    Peng, T.-C; Despois, D; Brouillet, N; Baudry, A; Favre, C; Remijan, A; Wootten, A; Wilson, T. L; Combes, F; Wlodarczak, G

    2013-01-01

    ...) and oxygen-bearing (e.g., HCOOCH3) molecules. However, acetone (CH3)2CO, a special complex O-bearing molecule, has been shown to have a very different distribution from other typical O-bearing molecules in the BN/KL region...

  5. A first-principle investigation into effect of B-and BN-doped C60 in ...

    Indian Academy of Sciences (India)

    principle investigation into effect of B- and BN-doped C 60 in lowering dehydrogenation of MXH 4 (where M = Na, Li and X = Al, B). MEENAKSHI DEEPAK AGNIHOTRI KIRAN JEET HITESH SHARMA. Volume 40 Issue 7 December 2017 pp 1397-1403 ...

  6. Emergence of Interfacial Polarons from Electron-Phonon Coupling in Graphene/h-BN van der Waals Heterostructures.

    Science.gov (United States)

    Chen, Chaoyu; Avila, José; Wang, Shuopei; Wang, Yao; Mucha-Kruczyński, Marcin; Shen, Cheng; Yang, Rong; Nosarzewski, Benjamin; Devereaux, Thomas P; Zhang, Guangyu; Asensio, Maria Carmen

    2018-02-14

    van der Waals heterostructures, vertical stacks of layered materials, offer new opportunities for novel quantum phenomena which are absent in their constituent components. Here we report the emergence of polaron quasiparticles at the interface of graphene/hexagonal boron nitride (h-BN) heterostructures. Using nanospot angle-resolved photoemission spectroscopy, we observe zone-corner replicas of h-BN valence band maxima, with energy spacing coincident with the highest phonon energy of the heterostructure, an indication of Fröhlich polaron formation due to forward-scattering electron-phonon coupling. Parabolic fitting of the h-BN bands yields an effective mass enhancement of ∼2.3, suggesting an intermediate coupling strength. Our theoretical simulations based on Migdal-Eliashberg theory corroborate the experimental results, allowing the extraction of microscopic physical parameters. Moreover, renormalization of graphene π-band is observed due to the hybridization with the h-BN band. Our work generalizes the polaron study from transition metal oxides to van der Waals heterostructures with higher material flexibility, highlighting interlayer coupling as an extra degree of freedom to explore emergent phenomena.

  7. Test tasks for verification of program codes for calculation of neutron-physical characteristics of the BN series reactors

    Science.gov (United States)

    Tikhomirov, Georgy; Ternovikh, Mikhail; Smirnov, Anton; Saldikov, Ivan; Bahdanovich, Rynat; Gerasimov, Alexander

    2017-09-01

    System of test tasks is presented with the fast reactor BN-1200 with nitride fuel as prototype. The system of test tasks includes three test based on different geometric models. Model of fuel element in homogeneous and in heterogeneous form, model of fuel assembly in height-heterogeneous and full heterogeneous form, and modeling of the active core of BN-1200 reactor. Cross-verification of program codes was performed. Transition from simple geometry to more complex one allows to identify the causes of discrepancies in the results during the early stage of cross-verification of codes. This system of tests can be applied for certification of engineering programs based on the method of Monte Carlo to the calculation of full-scale models of the reactor core of the BN series. The developed tasks take into account the basic layout and structural features of the reactor BN-1200. They are intended for study of neutron-physical characteristics, estimation of influence of heterogeneous structure and influence of diffusion approximation. The development of system of test tasks allowed to perform independent testing of programs for calculation of neutron-physical characteristics: engineering programs JARFR and TRIGEX, and codes MCU, TDMCC, and MMK based on the method of Monte Carlo.

  8. Inheritance and expression patterns of BN28, a low temperature induced gene in Brassica napus, throughout the Brassicaceae.

    Science.gov (United States)

    Hawkins, G P; Nykiforuk, C L; Johnson-Flanagan, A M; Boothe, J G

    1996-08-01

    Molecular genetics is becoming an important tool in the breeding and selection of agronomically important traits. BN28 is a low temperature induced gene in Brassicaceae species. PCR and Southern blot analysis indicate that BN28 is polymorphic in the three diploid genomes: Brassica rapa (AA), Brassica nigra (BB), and Brassica oleracea (CC). Of the allotetraploids, Brassica napus (AACC) is the only species to have inherited homologous genes from both parental genomes. Brassica juncea (AABB) and Brassica carinata (BBCC) have inherited homologues from the AA and CC genomes, respectively, while Sinapsis arvensis (SS) contains a single homologue from the BB genome and Sinapsis alba (dd) appears to be different from all the diploid parents. All species show message induction when exposed to low temperature. However, differences in expression were noticed at the protein level, with silencing occurring in the BB genome at the level of translation. Results suggest that silencing is occurring in diploid species where duplication may not have occurred. Molecular characterization and inheritance of BN28 homologues in the Brassicaceae may play an important role in determining their quantitative function during exposure to low temperature. Key words : Brassicaceae, BN28, inheritance, polymorphism.

  9. Analytical Study of the Propagation of Fast Longitudinal Modes along wz-BN/AlN Thin Acoustic Waveguides

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2015-01-01

    Full Text Available The propagation of the fundamental symmetric Lamb mode S0 along wz-BN/AlN thin composite plates suitable for telecommunication and sensing applications is studied. The investigation of the acoustic field profile across the plate thickness revealed the presence of modes having longitudinal polarization, the Anisimkin Jr. plate modes (AMs, travelling at a phase velocity close to that of the wz-BN longitudinal bulk acoustic wave propagating in the same direction. The study of the S0 mode phase velocity and coupling coefficient (K2 dispersion curves, for different electrical boundary conditions, has shown that eight different coupling configurations are allowable that exhibit a K2 as high as about 4% and very high phase velocity (up to about 16,700 m/s. The effect of the thickness and material type of the metal floating electrode on the K2 dispersion curves has also been investigated, specifically addressing the design of an enhanced coupling device. The gravimetric sensitivity of the BN/AlN-based acoustic waveguides was then calculated for both the AMs and elliptically polarized S0 modes; the AM-based sensor velocity and attenuation shifts due to the viscosity of a surrounding liquid was theoretically predicted. The performed investigation suggests that wz-BN/AlN is a very promising substrate material suitable for developing GHz band devices with enhanced electroacoustic coupling efficiency and suitable for application in telecommunications and sensing fields.

  10. High-temperature compressive deformation of Si{sub 3}N{sub 4}/BN fibrous monoliths.

    Energy Technology Data Exchange (ETDEWEB)

    Routbort, J. L.

    1999-02-04

    Fibrous monolithic Si{sub 3}N{sub 4}/BN ({approx}85 vol.% Si{sub 3}N{sub 4}/15 vol.% BN) and monolithic Si{sub 3}N{sub 4} ceramics were compressed at a nearly constant strain rate ({var_epsilon}) at 1200-1400 C in N{sub 2}. The {var_epsilon} range was {approx}1 x 10{sup {minus}6} to 5 x 10{sup {minus}6} s{sup {minus}1}; the stress ({sigma}) range was 37-202 MPa. The Si{sub 3}N{sub 4} and the unidirectional fibrous monoliths that were oriented with the long axis of the Si{sub 3}N{sub 4} cells parallel to the compression direction exhibited plasticity at 1300 and 1400 C, with {var_epsilon} {proportional_to} {sigma}. A 0/90{degree} cross-ply Si{sub 3}N{sub 4}/BN laminate also exhibited significant plasticity, but it was weaker than the above-mentioned ceramics. The unidirectional fibrous monoliths that were compressed perpendicular to the cell direction fractured at {approx}50 MPa in all tests. A {+-}45{degree} laminate tested at 1300 C fractured at a stress of {approx}40 MPa. Low fracture stress correlated with shear through BN layers.

  11. Translation and validation of the EORTC brain cancer module (EORTC QLQ-BN20) for use in Iran

    NARCIS (Netherlands)

    Khoshnevisan, A.; Yekaninejad, M.S.; Ardakani, S.K.; Pakpour, A.H.; Mardani, A.; Aaronson, N.K.

    2012-01-01

    Background The aim of this study was to translate the EORTC quality of life questionnaire for brain cancer, the QLQ-BN20, into Persian, and to evaluate its psychometric properties when used among brain cancer patients in Iran. Methods A standard backward and forward translation procedure was used to

  12. The BnGRF2 gene (GRF2-like gene from Brassica napus) enhances seed oil production through regulating cell number and plant photosynthesis.

    Science.gov (United States)

    Liu, Jing; Hua, Wei; Yang, Hong-Li; Zhan, Gao-Miao; Li, Rong-Jun; Deng, Lin-Bin; Wang, Xin-Fa; Liu, Gui-Hua; Wang, Han-Zhong

    2012-06-01

    Seed yield and oil content are two important agricultural characteristics in oil crop breeding, and a lot of functional gene research is being concentrated on increasing these factors. In this study, by differential gene expression analyses between rapeseed lines (zy036 and 51070) which exhibit different levels of seed oil production, BnGRF2 (Brassica napus growth-regulating factor 2-like gene) was identified in the high oil-producing line zy036. To elucidate the possible roles of BnGRF2 in seed oil production, the cDNA sequences of the rapeseed GRF2 gene were isolated. The Blastn result showed that rapeseed contained BnGRF2a/2b which were located in the A genome (A1 and A3) and C genome (C1 and C6), respectively, and the dominantly expressed gene BnGRF2a was chosen for transgenic research. Analysis of 35S-BnGRF2a transgenic Arabidopsis showed that overexpressed BnGRF2a resulted in an increase in seed oil production of >50%. Moreover, BnGRF2a also induced a >20% enlargement in extended leaves and >40% improvement in photosynthetic efficiency because of an increase in the chlorophyll content. Furthermore, transcriptome analyses indicated that some genes associated with cell proliferation, photosynthesis, and oil synthesis were up-regulated, which revealed that cell number and plant photosynthesis contributed to the increased seed weight and oil content. Because of less efficient self-fertilization induced by the longer pistil in the 35S-BnGRF2a transgenic line, Napin-BnGRF2a transgenic lines were further used to identify the function of BnGRF2, and the results showed that seed oil production also could increase >40% compared with the wild-type control. The results suggest that improvement to economically important characteristics in oil crops may be achieved by manipulation of the GRF2 expression level.

  13. Single-step synthesis of crystalline h-BN quantum- and nanodots embedded in boron carbon nitride films

    Science.gov (United States)

    Matsoso, Boitumelo J.; Ranganathan, Kamalakannan; Mutuma, Bridget K.; Lerotholi, Tsenolo; Jones, Glenn; Coville, Neil J.

    2017-03-01

    Herein we report on the synthesis and characterization of novel crystalline hexagonal boron nitride (h-BN) quantum- and nanodots embedded in large-area boron carbon nitride (BCN) films. The films were grown on a Cu substrate by an atmospheric pressure chemical vapour deposition technique. Methane, ammonia, and boric acid were used as precursors for C, N and B to grow these few atomic layer thick uniform films. We observed that both the size of the h-BN quantum/nanodots and thickness of the BCN films were influenced by the vaporization temperature of boric acid as well as the H3BO3 (g) flux over the Cu substrate. These growth conditions were easily achieved by changing the position of the solid boric acid in the reactor with respect to the Cu substrate. Atomic force microscope (AFM) and TEM analyses show a variation in the h-BN dot size distribution, ranging from nanodots (˜224 nm) to quantum dots (˜11 nm) as the B-source is placed further away from the Cu foil. The distance between the B-source and the Cu foil gave an increase in the C atomic composition (42 at% C-65 at% C) and a decrease in both B and N contents (18 at% B and 14 at% N to 8 at% B and 7 at% N). UV-vis absorption spectra showed a higher band gap energy for the quantum dots (5.90 eV) in comparison with the nanodots (5.68 eV) due to a quantum confinement effect. The results indicated that the position of the B-source and its reaction with ammonia plays a significant role in controlling the nucleation of the h-BN quantum- and nanodots. The films are proposed to be used in solar cells. A mechanism to explain the growth of h-BN quantum/nanodots in BCN films is reported.

  14. Corrugation in the Weakly Interacting Hexagonal-BN/Cu(111) System: Structure Determination by Combining Noncontact Atomic Force Microscopy and X-ray Standing Waves.

    Science.gov (United States)

    Schwarz, Martin; Riss, Alexander; Garnica, Manuela; Ducke, Jacob; Deimel, Peter S; Duncan, David A; Thakur, Pardeep Kumar; Lee, Tien-Lin; Seitsonen, Ari Paavo; Barth, Johannes V; Allegretti, Francesco; Auwärter, Willi

    2017-09-26

    Atomically thin hexagonal boron nitride (h-BN) layers on metallic supports represent a promising platform for the selective adsorption of atoms, clusters, and molecular nanostructures. Specifically, scanning tunneling microscopy (STM) studies revealed an electronic corrugation of h-BN/Cu(111), guiding the self-assembly of molecules and their energy level alignment. A detailed characterization of the h-BN/Cu(111) interface including the spacing between the h-BN sheet and its support-elusive to STM measurements-is crucial to rationalize the interfacial interactions within these systems. To this end, we employ complementary techniques including high-resolution noncontact atomic force microscopy, STM, low-energy electron diffraction, X-ray photoelectron spectroscopy, the X-ray standing wave method, and density functional theory. Our multimethod study yields a comprehensive, quantitative structure determination including the adsorption height and the corrugation of the sp(2) bonded h-BN layer on Cu(111). Based on the atomic contrast in atomic force microscopy measurements, we derive a measurable-hitherto unrecognized-geometric corrugation of the h-BN monolayer. This experimental approach allows us to spatially resolve minute height variations in low-dimensional nanostructures, thus providing a benchmark for theoretical modeling. Regarding potential applications, e.g., as a template or catalytically active support, the recognition of h-BN on Cu(111) as a weakly bonded and moderately corrugated overlayer is highly relevant.

  15. Energetics of a Li Atom adsorbed on B/N doped graphene with monovacancy

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Babita, E-mail: babitabaghla15@gmail.com [Department of Physics, Panjab University, Chandigarh 160014 (India); Department of Physics, Punjabi University, Patiala 147002 (India); Jindal, V.K. [Department of Physics, Panjab University, Chandigarh 160014 (India); Dharamvir, Keya, E-mail: keya@pu.ac.in [Department of Physics, Panjab University, Chandigarh 160014 (India)

    2016-08-15

    We use density functional theory (DFT) to study the adsorption properties and diffusion of Li atom across B/N-pyridinic graphene. Regardless of the dopant type, B atoms of B-pyridinic graphene lose electron density. On the other hand, N atoms (p-type dopants) have tendency to gain electron density in N-pyridinic graphene. Higher chemical reactivity and electronic conductivity of B/N-pyridinic graphene are responsible for stronger binding of Li with the substrates as compared to pristine graphene. The binding energy of Li with B/N-pyridinic graphene exceeds the cohesive energy of bulk Li, making it energetically unfavourable for Li to form clusters on these substrates. Li atom gets better adsorbed on N-pyridinic graphene due to an additional p-p hybridization of the orbitals while Li on B-pyridinic prefers the ionic bonding. Also, significant distortion of N-pyridinic graphene upon Li adsorption is a consequence of the change in bonding mechanism between Li atom and the substrate. Our results show that bonding character and hence binding energies between Li and graphene can be tuned with the help of B/N doping of monovacancy defects. Further, the sites for most stable adsorption are different for the two types of doped and defective graphene, leading to greater Li uptake capacity of B-pyridinic graphene near the defect. In addition, B-pyridinic graphene offering lower diffusion barrier, ensures better Li kinetics. Thus, B-pyridinic graphene presents itself as a better anode material for LIBs as compared to N-pyridinic graphene. - Graphical abstract: Adsorption and diffusion of Li atom across the B/N doped monovacancy graphene is studied using ab-initio DFT calculations. Our results show that bonding mechanism and binding of Li with graphene can be tuned with the help of N/B doping of defects. Also, B-pyridinic graphene presents itself as a better anode material for lithium ion batteries as compared to N-pyridinic graphene. Display Omitted - Highlights: • Density

  16. VizieR Online Data Catalog: Near-IR BN/KL outflow images (Bally+, 2015)

    Science.gov (United States)

    Bally, J.; Ginsburg, A.; Silvia, D.; Youngblood, A.

    2015-02-01

    The Gemini Multi-conjugate adaptive optics System (GeMS) at the Gemini South telescope on Cerro Pachon is the first and only sodium-based multi-laser guide star (LGS) adaptive optics system. GeMS works with a LGS constellation of 5-spots: 4 of the LGS spots are at the corners of a 60" square, with the 5-th positioned in the center. The Adaptive Optics (AO) bench called Canopus is mounted on one of the f/16 Cassegrain ports. Gemini South Adaptive Optics Imager (GSAOI) is a wide-field 4096 by 4096 pixel (85" by 85" field of view) camera designed to work at the diffraction limit of the 8- meter telescope in the near-infrared. Three 85" diameter fields were observed in OMC1 between 30 December 2012 and 28 February 2013 using GSAOI. Observations of each field were obtained through 1% bandpass narrow-band filters centered on the 1.644um [FeII] and 2.122um H2 emission lines and the broad-band Ks filter. The corrected images have FWHM diameters of 0.080" to 0.10", providing the highest angular resolution images of the BN/KL outflow ever obtained in the near-IR. (2 data files).

  17. Study of the $d(^{7}Be,^{8}B)n$ reaction

    CERN Document Server

    Powell, C F; Anthony, D W; Davids, B; Fauerbach, M; Mantica, P F; Sherrill, B M; Steiners, M

    1998-01-01

    The (d, n) reaction of /sup 7/Be to form the ground state of /sup 8/B was studied in inverse kinematics using a 25 MeV/nucleon beam of /sup 7/Be nuclei from the A1200 fragment separator at the NSCL. The recoiling /sup 8/B nuclei were observed in a pair of position sensitive detector telescopes at lab angles between 10 and 5.5 degrees (7 degrees to 38 degrees CMS). A large array of neutron detectors was placed at angles ranging from 158 degrees to 104 degrees (35 degrees to 7 degrees CMS) that measured the energy of coincident neutrons by their time-of-flight. The cross section for the d(/sup 7/Be,/sup 8/B)n reaction was determined from both the charged-particle singles and from the neutron coincidence data. In addition to measuring the transfer reaction, the quasi-elastic scattering of /sup 7/Be from deuterium was measured. The cross sections of these reactions are compared with DWBA and coupled- channels calculations. (19 refs).

  18. Structural and electro-optical properties of bilayer graphyne like BN sheet

    Science.gov (United States)

    Behzad, Somayeh

    2016-12-01

    The structural, electronic and optical properties of bilayer graphyne like BN sheet (BNyne) with different stacking manners have been explored by the first-principles calculations. The stabilities of α-BNyne bilayers with different stacking manners are compared. The α-BNyne Bilayers have wide band gaps. Compared to the single α-BNyne, the numbers of energy bands are doubled due to the interlayer interactions and the band gap is reduced. The AB-I configuration has a direct band gap while the band gap becomes indirect for AA-II. The calculated ε2 (ω) of bilayer α-BNyne for (Eǁx) is similar to that of the monolayer α-BNyne, except for the small changes of peak positions and increasing of peak intensities. For (Eǁz), the first absorption peak occures at 3.86 eV, and the prominant peak of monolayer at 9.17 eV becomes broadened. These changes are related to the new transitions resulting from the band splitting.

  19. LIBERAL MEASURES AND STRONG POWER. TO THE 190TH BIRTHDAY OF B.N. CHICHERIN

    Directory of Open Access Journals (Sweden)

    Aleksei Dmitrievich Nikotin

    2017-10-01

    Full Text Available Purpose: Identify the general and special in the views of Boris B. Chicherin, as the brightest representative of Russian liberalism at the turn of the XIX–XX centuries on the problem of Russia’s political system, the prospect of the development of civil and political freedoms. Research methodology: when working with the texts analyzed was used the comparative method, system method. The results of the study: The article examines the political and philosophical views of the greatest theoretician of Russian liberalism at the turn of the XIX–XX centuries B.N. Chicherin. The author, noting the breadth of scientific views of the Russian liberal, concentrated on his ideas about Russia’s preferred form of government and the need to reform Russia’s state and legal system. Particular attention is paid to the views of Boris N. Chicherin on the problem of the exercise of individual freedom of a person, his civil and political rights in the conditions of strong state power, building up the legal system of interaction between the state and civil society. The scope of the results: the results can be applied in scientific politological and social-philosophical studies, and in the course of teaching of social and Humanities disciplines.

  20. 1D ferromagnetic edge contacts to 2D graphene/h-BN heterostructures

    Science.gov (United States)

    Karpiak, Bogdan; Dankert, André; Cummings, Aron W.; Power, Stephen R.; Roche, Stephan; Dash, Saroj P.

    2018-03-01

    We report the fabrication of one-dimensional (1D) ferromagnetic edge contacts to two-dimensional (2D) graphene/h-BN heterostructures. While aiming to study spin injection/detection with 1D edge contacts, a spurious magnetoresistance signal was observed, which is found to originate from the local Hall effect in graphene due to fringe fields from ferromagnetic edge contacts and in the presence of charge current spreading in the nonlocal measurement configuration. Such behavior has been confirmed by the absence of a Hanle signal and gate-dependent magnetoresistance measurements that reveal a change in sign of the signal for the electron- and hole-doped regimes, which is in contrast to the expected behavior of the spin signal. Calculations show that the contact-induced fringe fields are typically on the order of hundreds of mT, but can be reduced below 100 mT with careful optimization of the contact geometry. There may be an additional contribution from magnetoresistance effects due to tunneling anisotropy in the contacts, which needs further investigation. These studies are useful for optimization of spin injection and detection in 2D material heterostructures through 1D edge contacts.

  1. Exploring dissociative water adsorption on isoelectronically BN doped graphene using alchemical derivatives

    Science.gov (United States)

    Al-Hamdani, Yasmine S.; Michaelides, Angelos; von Lilienfeld, O. Anatole

    2017-10-01

    The design and production of novel 2-dimensional materials have seen great progress in the last decade, prompting further exploration of the chemistry of such materials. Doping and hydrogenating graphene are an experimentally realised method of changing its surface chemistry, but there is still a great deal to be understood on how doping impacts on the adsorption of molecules. Developing this understanding is key to unlocking the potential applications of these materials. High throughput screening methods can provide particularly effective ways to explore vast chemical compositions of materials. Here, alchemical derivatives are used as a method to screen the dissociative adsorption energy of water molecules on various BN doped topologies of hydrogenated graphene. The predictions from alchemical derivatives are assessed by comparison to density functional theory. This screening method is found to predict dissociative adsorption energies that span a range of more than 2 eV, with a mean absolute error water is reduced by almost an order of magnitude (down to ˜0.02 eV) after filtering out poor predictions. The findings point the way towards a reliable use of first order alchemical derivatives for efficient screening procedures.

  2. First-principles calculations and model analysis of plasmon excitations in graphene and graphene/hBN heterostructure

    Science.gov (United States)

    Li, Pengfei; Ren, Xinguo; He, Lixin

    2017-10-01

    Plasmon excitations in free-standing graphene and graphene/hexagonal boron nitride (hBN) heterostructure are studied using linear-response time-dependent density functional theory within the random phase approximation. Within a single theoretical framework, we examine both the plasmon dispersion behavior and lifetime (linewidth) of Dirac and π plasmons on an equal footing. Particular attention is paid to the influence of the hBN substrate and the anisotropic effect. Furthermore, a model-based analysis indicates that the correct dispersion behavior of π plasmons should be ωπ(q ) =√{Eg2+β ql} for small q 's, where Eg is the band gap at the M point in the Brillouin zone, and β is a fitting parameter. This model is radically different from previous proposals, but in good agreement with our calculated results from first principles.

  3. Impact of diet on ozone-induced pulmonary and systemic effects in female Brown Norway (BN) rats

    Science.gov (United States)

    Impact of diet on ozone-induced pulmonary and systemic effects in female Brown Norway (BN) ratsV.L. Bass1, M.C. Schladweiler2, S. Snow5, C.J. Gordon4, K.A. Jarema4, P. Phillips4, A.D. Ledbetter2, D.B. Miller3, J.E. Richards2, U.P. Kodavanti2. 1. SPH, UNC, Chapel Hill2. EPHD, NHE...

  4. Structure investigation of BN films grown by ion-beam-assisted deposition by means of polarised IR and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ben el Mekki, M.; Djouadi, M.A.; Guiot, E.; Mortet, V. [ENSAM, Cluny (France). Lab. Bourguignon des Materiaux et Procedes; Pascallon, J.; Stambouli, V.; Bouchier, D. [Institut d' Electronique Fondamentale, Universite Paris-Sud, Orsay (France); Mestres, N. [Institut de Ciencia de Materials de Barcelona (CSIC), E-08193, Bellaterra (Spain); Nouet, G. [LERMAT, ISMRA, Caen (France)

    1999-09-01

    We present an optical investigation, by means of polarised infrared (IR) spectroscopy and Raman scattering, of the microstructure and crystallinity of mixed films of hexagonal and cubic boron nitride (h-BN and c-BN, respectively). The films were deposited on an unheated silicon substrate by the ion-beam-assisted deposition method (IBAD) at low energy (400-500 eV). The deposition temperature, due to the ion bombardment, was in the range 200-250 C at the end of the deposition process. Different film types were grown on a silicon substrate of dimensions 75 mm x 15 mm by changing the ion (nitrogen+argon) to atom (thermal boron) arrival ratio, {phi}{sub ion}/{phi}{sub B}, in the range 0.69-3. Polarised IR reflectivity (PIRR) spectra were acquired at different positions on the BN film (different arrival ratios {phi}{sub ion}/{phi}{sub B}) and show an important upwards shift of transverse optical (TO) and longitudinal optical (LO) phonons of the twofold degenerated mode E{sub 1u} of the sp{sup 2} phase at the transition zone from sp{sup 2} to sp{sup 3} phases. Several processes can shift the IR phonon peaks, including the degree of crystallinity, film thickness, film stoichiometry and intrinsic stress. The micro-Raman results and the full-width at half-maximum values of TO phonons of the E{sub 1u} mode show that the BN film has a similar crystallinity in all regions. The effect of the film thickness was shown by using a microstructure-dependent model for the IR anisotropic effective dielectric function of thin films. (orig.)

  5. Tailoring the electronic properties of a Z-shaped graphene field effect transistor via B/N doping

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Mohit; Gaur, Nitesh; Kumar, Puneet; Singh, Sangeeta [Nanoelectronics and VLSI Lab., Indian Institute of Information Technology, Design and Manufacturing (IIITDM), Jabalpur 482005 (India); Jaiswal, Neeraj K., E-mail: neeraj@iiitdmj.ac.in [Discipline of Physics, Indian Institute of Information Technology, Design and Manufacturing (IIITDM), Jabalpur 482005 (India); Kondekar, P.N. [Nanoelectronics and VLSI Lab., Indian Institute of Information Technology, Design and Manufacturing (IIITDM), Jabalpur 482005 (India)

    2015-03-20

    We performed first-principles calculations to reveal a viable way for tailoring the electronic properties of Z-shaped double gate graphene field effect transistor (Z-GFET). We used B/N impurities in channel region of Z-GFET. It is revealed that doping of channel region by B/N has a significant effect on its band gap which is directly reflected in the corresponding current–voltage characteristics. A semiconducting to metallic transition is also observed in selected configurations. For B–N co-doping (config. W), direct band gap of 1.84 eV is obtained which is 20% lower than that of pristine channel. Present results are useful for future electronic devices. - Highlights: • Doping of B/N can be used to tailor the electronic properties of graphene based FET. • The band structure is sensitive to doping site as well as doping concentration. • B–N co-doped channel exhibits 20% lower band gap than that of pristine channel. • Configurations with N doped channel show highest current amongst others.

  6. Reversible Hydrogen Uptake by BN and BC3 Monolayers Functionalized with Small Fe Clusters: A Route to Effective Energy Storage.

    Science.gov (United States)

    Hussain, Tanveer; Searles, Debra J; Takahashi, Keisuke

    2016-03-31

    In an effort to design new functionalized nanostructures for clean energy storage, DFT calculations of Fen (n = 1-3) clusters on BC3 and BN monolayers are performed. The stability of the systems was considered by calculating the binding energies of the monolayers with Fen clusters on one or both sides. All the clusters bound strongly to both the monolayers and transferred electron density to the sheets. The cationic Fe clusters were then able to adsorb multiple H2 molecules through electrostatic and van der Waals interactions. The average adsorption energies per H2 in the case of maximum coverage were calculated to be -0.389 and -0.358 eV for systems with one Fe on both sides of BC3 and BN monolayers, respectively. In these cases four H2 molecules were adsorbed to the Fe atoms on both sides of the monolayer. These adsorption energies are such that there is potential for adsorption/desorption at ambient conditions. The results provide insights into an efficient and reversible storage of H2 by using Fen-functionalized BC3 and BN monolayers.

  7. Bimetallic two-dimensional PtAg coverage on h-BN substrate: First-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ersan, F. [Department of Physics, Adnan Menderes University, Aydın 09100 (Turkey); Gökoğlu, G. [Department of Physics, Karabük University, Karabük 78050 (Turkey); Aktürk, E., E-mail: ethem.akturk@adu.edu.tr [Department of Physics, Adnan Menderes University, Aydın 09100 (Turkey)

    2014-06-01

    This paper presents a study on the coverage of PtAg layer on h-BN 2D system using plane-wave pseudopotential method within density functional theory. There emerge interesting electronic and magnetic properties by the coverage of PtAg on h-BN. FM (ferromagnetic) and AFM (antiferromagnetic) states are considered for PtAg. As the most stable configuration, Pt atom is bound to the top site of N and Ag is adsorbed to hollow site in the (2 × 2) coverage with a binding energy about −1.013 eV. While bare h-BN is nonmagnetic semiconductor with a band gap of 4.58 eV, the band gap becomes 0.18 eV with an AFM semiconductor ground state upon coverage of PtAg adlayer. The electronic structure calculations reveal that the electronic band gap of the composite system is controlled by d-states of Pt atom. The material can have possible applications in spintronics and in catalysis with decreased and engineered band gap.

  8. Stability and electronic properties of hybrid SnO bilayers: SnO/graphene and SnO/BN

    Science.gov (United States)

    Guo, Qing; Wang, Gaoxue; Kumar, Ashok; Pandey, Ravindra

    2017-11-01

    Van der Waals structures based on two-dimensional materials have been considered as promising structures for novel nanoscale electronic devices. Two-dimensional SnO films which display intrinsic p-type semiconducting properties were fabricated recently. In this paper, we consider vertically stacked heterostructures consisting of a SnO monolayer with graphene or a BN monolayer to investigate their stability, electronic and transport properties using density functional theory. The calculated results find that the properties of the constituent monolayers are retained in these SnO-based heterostructures, and a p-type Schottky barrier is formed in the SnO/graphene heterostructure. Additionally, the Schottky barrier can be effectively controlled with an external electric field, which is useful characteristic for the van der Waals heterostructure-based electronic devices. In the SnO/BN heterostructure, the electronic properties of SnO are least affected by the insulating monolayer suggesting that the BN monolayer would be an ideal substrate for SnO-based nanoscale devices.

  9. Microstructure and Tensile Properties of BN/SiC Coated Hi-Nicalon, and Sylramic SiC Fiber Preforms

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Chen, Yuan L.; Morscher, Gregory N.

    2001-01-01

    Batch to batch and within batch variations, and the influence of fiber architecture on room temperature physical and tensile properties of BN/SiC coated Hi-Nicalon and Sylramic SiC fiber preform specimens were determined. The three fiber architectures studied were plain weave (PW), 5-harness satin (5HS) and 8-harness satin (8HS) Results indicate that the physical properties vary up to 10 percent within a batch, and up to 20 percent between batches of preforms. Load-reload (Hysteresis) and acoustic emission methods were used to analyze damage accumulation occurring during tensile loading. Early acoustic emission activity, before observable hysteretic behavior, indicates that the damage starts with the formation of nonbridged tunnel cracks. These cracks then propagate and intersect the load bearing "0" fibers giving rise to hysteretic behavior, For the Hi-Nicalon preform specimens, the onset of "0" bundle cracking stress and strain appeared to be independent of the fiber architecture. Also, the "0" fiber bundle cracking strain remained nearly the same for the preform specimens of both fiber types. Transmission Electron Microscope (TEM) analysis indicates that the Chemical Vapor Infiltration (CVI) Boron Nitride (BN) interface coating is mostly amorphous and contains carbon and oxygen impurities, and the CVI SiC coating is crystalline. No reaction exists between the CVI BN and SiC coating.

  10. Quick Maintenance for High Voltage Equipment with the New Not Toxic Boron Nitride Powder (BN100) Superior Thermal Conductive and Lightweight Filler

    National Research Council Canada - National Science Library

    Boer, Fabrizio

    2005-01-01

    .... The BN100 superior thermal conductive and lightweight filler technology is a new filler technology, that not only lets Users a full access for maintenance because cure-free being compounded by loose...

  11. The Evolution of Interfacial Sliding Stresses During Cyclic Push-in Testing of C- and BN-Coated Hi-Nicalon Fiber-Reinforced CMCs

    Science.gov (United States)

    Eldridge, J. I.; Bansal, N. P.; Bhatt, R. T.

    1998-01-01

    Interfacial debond cracks and fiber/matrix sliding stresses in ceramic matrix composites (CMCs) can evolve under cyclic fatigue conditions as well as with changes in the environment, strongly affecting the crack growth behavior, and therefore, the useful service lifetime of the composite. In this study, room temperature cyclic fiber push-in testing was applied to monitor the evolution of frictional sliding stresses and fiber sliding distances with continued cycling in both C- and BN-coated Hi-Nicalon SiC fiber-reinforced CMCs. A SiC matrix composite reinforced with C-coated Hi-Nical on fibers as well as barium strontium aluminosilicate (BSAS) matrix composites reinforced with BN-coated (four different deposition processes compared) Hi-Nicalon fibers were examined. For failure at a C interface, test results indicated progressive increases in fiber sliding distances during cycling in room air but not in nitrogen. These results suggest the presence of moisture will promote crack growth when interfacial failure occurs at a C interface. While short-term testing environmental effects were not apparent for failure at the BN interfaces, long-term exposure of partially debonded BN-coated fibers to humid air resulted in large increases in fiber sliding distances and decreases in interfacial sliding stresses for all the BN coatings, presumably due to moisture attack. A wide variation was observed in debond and frictional sliding stresses among the different BN coatings.

  12. How to Increase the h-BN Crystallinity of Microfilms and Self-Standing Nanosheets: A Review of the Different Strategies Using the PDCs Route

    Directory of Open Access Journals (Sweden)

    Sheng Yuan

    2016-05-01

    Full Text Available Hexagonal boron nitride (h-BN is a well-known material whose use is almost restricted to lubricating applications in domains ranging from metallurgy to cosmetics. Howover, h-BN displays many other interesting properties, opening new perspectives for other engineering applications, such as as a solid lubricant in aeronautics, as the perfect substrate to graphene for electronic devices, etc. However, all these promising developments require tailored h-BN shapes displaying a high level of crystallization, ensuring its properties for the long term. Here, we developed three strategies, all associated with the Polymer Derived Ceramics (PDCs route, to prepare highly crystallized supported thick coatings and self-standing nanosheets. The first strategy concerns the innovative implementation of a Rapid Thermal Annealing to prepare micrometric h-BN coatings on thermal sensitive substrates. Compared to conventional treatment the crystallization of h-BN has successfully lowered to about 300 °C. The second strategy consists of an additivation of the used polymer precursor. Effect of lithium nitride as a crystallization promoter was investigated lowering the onset crystallization temperature from 1400 °C (traditionally to 1000 °C. This novel synthetic route allows preparing self-standing highly crystallized h-BN nanolayers. Finally, the third strategy is based on a unique combination of the PDCs route with Spark Plasma Sintering to profit of both approaches. This original method leads to large and well-crystallized flakes available for a subsequent exfoliation.

  13. The biological characterization of {sup 99m}Tc-BnAO-NI as a SPECT probe for imaging hypoxia in a sarcoma-bearing mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Hsia, Chien-Chung [Institute of Biomedical imaging and Radiological Sciences, National Yang-Ming University, Taiwan (China); Institute of Nuclear Energy Research, Taiwan (China); Huang, Fu-Lei [Institute of Nuclear Energy Research, Taiwan (China); Hung, Guang-Uei [Department of Nuclear Medicine, Chang-Bing Show Chwan Hospital, Taiwan (China); Shen, Lie-Hang [Institute of Nuclear Energy Research, Taiwan (China); Chen, Chuan-Lin, E-mail: clchen2@ym.edu.t [Institute of Biomedical imaging and Radiological Sciences, National Yang-Ming University, Taiwan (China); Wang, Hsin-Ell, E-mail: hewang@ym.edu.t [Institute of Biomedical imaging and Radiological Sciences, National Yang-Ming University, Taiwan (China)

    2011-04-15

    Objectives: Tumor growth beyond the region where vascular oxygen can reach creates a hypoxic domain. In this study, BnAO, a ligand that had been labeled with {sup 99m}Tc-pertechnetate for hypoxia imaging, was conjugated with 2-nitroimidazole to give 3,3,10,10-tetramethyl-1-(2-nitro-1H-imidazo-1-y1)-4,9-diazadodecane-2,11- dionedioxime (BnAO-NI) as a potential ligand for hypoxia detection. Pentoxifylline is a peripheral vasodilator and has been used as a radiosensitizer in tumor radiotherapy. {sup 99m}Tc-BnAO-NI/SPECT was applied to noninvasively assess the pharmacological effect of pentoxifylline in reducing tumor hypoxia in vivo. Methods: BnAO-NI was synthesized and formulated with methylene diphosphonate (MDP), stannous chloride and carbonate buffer to afford kits. After mixing with {sup 99m}Tc-pertechnetate, {sup 99m}Tc-BnAO-NI injection can be readily prepared. The partition coefficient, radiochemical purity and in vitro stability were determined. Cellular uptake of radiotracers in KHT cells under hypoxia was conducted in a CO{sub 2} incubator at 37 {sup o}C under hypoxia or normoxia. A biodistribution study after intravenous injection of {sup 99m}Tc-BnAO-NI in KHT sarcoma-implanted C3H mice was performed. The effect of pentoxifylline (100 mg/kg) on reducing tumor hypoxia was also studied. Results: The radiochemical purity (RCP) of the {sup 99m}Tc-BnAO-NI preparation was greater than 96% and stable at ambient temperature for 24 h (RCP>90%). The accumulation of {sup 99m}Tc-BnAO-NI and {sup 99m}Tc-BnAO in KHT cells under hypoxia were 3.57 and 4.13-fold higher than those under normoxic environment, indicating unambiguous oxygen-dependent uptakes of these two probes. The distribution of {sup 99m}Tc-BnAO-NI in KHT sarcoma-bearing mice revealed rapid clearance from the blood circulation. The tumor uptake peaked at 2 h post-injection (0.32{+-}0.05%ID/g) with tumor-to-blood and tumor-to-muscle ratios of 10.32 and 3.96, respectively. The effect of pentoxifylline on the

  14. Dosimetric consequences of 10B(n, alpha)7Li reaction occurring at the cellular membrane.

    Science.gov (United States)

    Kalend, A M; Bloomer, W D; Epperly, M W

    1995-01-01

    Microdosimetric expectations of Boron contents are extracted from a CRAY-Monte Carlo simulation of the nuclear reaction 10B(n, alpha)7Li as it occurs on a boronated membrane of a model cell and as the reaction fragments (alpha and Li) traverse into the cellular nucleus. The present microdosimetry calculation is based upon the assumption that the therapeutic advantage of boron neutron capture therapy (BNCT), while depending upon the RBE and LET of the reaction particles, is equally dependent on the boron carrier preferential localization to tumor tissue, and the boron selectivity to cancerous cells and its specificity within subcellular compartments. In particular, boron fixes to cell membrane as it ought to, using monoclonal antibodies. The present Monte Carlo simulation computes stochastic expectations of alpha/Li energy depositions to the nucleus in a uniformly boronated membrane shell of a spherical cell. Differential energy gain was deduced from the stochastic energy depositions in events of neutron reactions with membrane boron compared against those with natural elements (O, H, N) in the cell. Microdosimetry data are presented in terms of specific energy (keV/micron3) and lineal energy (keV/micron) functions of the nucleus-to-cell volume ratios (NCVR). When folded with the geometric boron content and accounting for background reaction energies, the distributions yield effective energy gain to the cell nucleus per neutron capture event. Boron amount required to yield these energy gains are found to be of the order of picograms of boron per gram of cell mass. The boron content as inferred by the present Monte Carlo microdosimetry compares well with that deliverable by present pharmacokinetic means, but are orders of magnitude (mu-grams) less than those deduced previously from anthropomorphic macrodosimetry.

  15. Fabrication, characterization, and mechanical properties of spark plasma sintered Al–BN nanoparticle composites

    Energy Technology Data Exchange (ETDEWEB)

    Firestein, Konstantin L., E-mail: kosty@firestein.ru [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Steinman, Alexander E.; Golovin, Igor S. [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Cifre, Joan [Universitat de les Illes Balears, Ctra. de Valldemossa, km. 7.5, E-07122 Palma de Mallorca (Spain); Obraztsova, Ekaterina A.; Matveev, Andrei T.; Kovalskii, Andrey M. [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Lebedev, Oleg I. [CRISMAT, UMR 6508, CNRS-ENSICAEN, 6Bd Marechal Juin, 14050 Caen (France); Shtansky, Dmitry V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky prospect 4, Moscow 119049 (Russian Federation); Golberg, Dmitri, E-mail: golberg.dmitri@nims.go.jp [World Premier International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science (NIMS), Namiki 1, Tsukuba, Ibaraki 3050044 (Japan)

    2015-08-26

    Fabrication of high strength yet light and low cost composite materials with good mechanical properties at room and elevated temperatures is a challenge that metallurgy and materials science communities are facing for many years, and no “dream material” has been developed so far. The primary goal of this study was to fabricate, characterize, and to carry out tensile tests on Al-based composite materials strengthened with commercially-available BN nanoparticles (BNNPs). The composites were fabricated by spark plasma sintering (SPS) technique. The structures of powder mixtures and composite materials, as well as their fracture surfaces, were studied by scanning and transmission electron microscopy. The influence of BNNPs content (0.5, 1.5, 3, 4.5, 6, and 7.5 wt%) and holding times (5, 60, and 300 min) at 600 °C during SPS on the tensile strength was investigated. A maximum increase in strength was observed for Al-based composites with 4.5 wt% of BNNPs. The sample demonstrated a 50% increase in tensile strength compared with pristine Al. Although the tensile tests performed at 300 °C revealed that the tensile strength became 20% lower than the strength at room temperature, it was, however, still 75% higher compared with that of the pure Al at 300 °C. In addition, at 300 °C the Al–BNNPs composites demonstrated a much higher value of yield stress, about 115 MPa, which is 190% higher than that of pure Al at the same temperature. The damping properties of Al–BNNPs composites were evaluated by temperature dependent internal friction (TDIF) measurements. The obtained results are discussed based on structural analysis and the TDIF data.

  16. Spontaneous doping on high quality talc-graphene-hBN van der Waals heterostructures

    Science.gov (United States)

    Mania, E.; Alencar, A. B.; Cadore, A. R.; Carvalho, B. R.; Watanabe, K.; Taniguchi, T.; Neves, B. R. A.; Chacham, H.; Campos, L. C.

    2017-09-01

    Steady doping, added to its remarkable electronic properties, would make graphene a valuable commodity in the solar cell market, as energy power conversion could be substantially increased. Here we report a graphene van der Waals heterostructure which is able to spontaneously dope graphene (p-type) up to n ~ 2.2  ×  1013 cm-2 while providing excellent charge mobility (μ ~ 25 000 cm2 V-1 s-1). Such properties are achieved via deposition of graphene on atomically flat layered talc, a natural and abundant dielectric crystal. Raman investigation shows a preferential charge accumulation on graphene-talc van der Waals heterostructures, which are investigated through the electronic properties of talc/graphene/hBN heterostructure devices. These heterostructures preserve graphene’s good electronic quality, verified by the observation of quantum Hall effect at low magnetic fields (B  =  0.4 T) at T  =  4.2 K. In order to investigate the physical mechanisms behind graphene-on-talc p-type doping, we performed first-principles calculations of their interface structural and electronic properties. In addition to potentially improving solar cell efficiency, graphene doping via van der Waals stacking is also a promising route towards controlling the band gap opening in bilayer graphene, promoting a steady n or p type doping in graphene and, eventually, providing a new path to access superconducting states in graphene, predicted to exist only at very high doping.

  17. Quality of Life in Patients With Brain Metastases Using the EORTC QLQ-BN20+2 and QLQ-C15-PAL

    Energy Technology Data Exchange (ETDEWEB)

    Caissie, Amanda; Nguyen, Janet; Chen, Emily; Zhang Liying [Rapid Response Radiotherapy Program, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Sahgal, Arjun [Rapid Response Radiotherapy Program, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Clemons, Mark [Department of Medical Oncology, Ottawa Hospital Cancer Centre, Ottawa, Ontario (Canada); Kerba, Marc [Department of Radiation Oncology, Tom Baker Cancer Centre, Calgary, Alberta (Canada); Arnalot, Palmira Foro [Parc de Salut Mar Hospital de l' Esperanca, Barcelona (Spain); Danjoux, Cyril; Tsao, May; Barnes, Elizabeth; Holden, Lori [Rapid Response Radiotherapy Program, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Danielson, Brita [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta (Canada); Chow, Edward, E-mail: edward.chow@sunnybrook.ca [Rapid Response Radiotherapy Program, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada)

    2012-07-15

    Purpose: The 20-item European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Brain Neoplasm (QLQ-BN20) is a validated quality-of-life (QOL) questionnaire for patients with primary brain tumors. The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15 Palliative (QLQ-C15-PAL) core palliative questionnaire is a 15-item version of the core 30-item QLQ-C30 and was developed to decrease the burden on patients with advanced cancer. The combination of the QLQ-BN20 and QLQ-C30 to assess QOL may be too burdensome for patients. The primary aim of this study was to assess QOL in patients before and after treatment for brain metastases using the QLQ-BN20+2 and QLQ-C15-PAL, a version of the QLQ-BN20 questionnaire with 2 additional questions assessing cognitive functioning that were not addressed in the QLQ-C15-PAL. Methods and Materials: Patients with brain metastases completed the QLQ-C15-PAL and QLQ-BN20+2 questionnaires to assess QOL before and 1 month after radiation. Linear regression analysis was used to assess changes in QOL scores over time, as well as to explore associations between the QLQ-BN20+2 and QLQ-C15-PAL scales, patient demographics, and clinical variables. Spearman correlation assessed associations between the QLQ-BN20+2 and QLQ-C15-PAL scales. Results: Among 108 patients, the majority (55%) received whole-brain radiotherapy only, with 65% of patients completing follow-up at 1 month after treatment. The most prominent symptoms at baseline were future uncertainty (QLQ-BN20+2) and fatigue (QLQ-C15-PAL). After treatment, significant improvement was seen for the QLQ-C15-PAL insomnia scale, as well as the QLQ-BN20+2 scales of future uncertainty, visual disorder, and concentration difficulty. Baseline Karnofsky Performance Status was negatively correlated to QLQ-BN20+2 motor dysfunction but positively related to QLQ-C15-PAL physical functioning and QLQ-BN20+2 cognitive functioning at

  18. Control of Nanoplane Orientation in voBN for High Thermal Anisotropy in a Dielectric Thin Film: A New Solution for Thermal Hotspot Mitigation in Electronics.

    Science.gov (United States)

    Cometto, Olivier; Samani, Majid K; Liu, Bo; Sun, Shuangxi; Tsang, Siu Hon; Liu, Johan; Zhou, Kun; Teo, Edwin H T

    2017-03-01

    High anisotropic thermal materials, which allow heat to dissipate in a preferential direction, are of interest as a prospective material for electronics as an effective thermal management solution for hot spots. However, due to their preferential heat propagation in the in-plane direction, the heat spreads laterally instead of vertically. This limitation makes these materials ineffective as the density of hot spots increases. Here, we produce a new dielectric thin film material at room temperature, named vertically ordered nanocrystalline h-BN (voBN). It is produced such that its preferential thermally conductive direction is aligned in the vertical axis, which facilitates direct thermal extraction, thereby addressing the increasing challenge of thermal crosstalk. The uniqueness of voBN comes from its h-BN nanocrystals where all their basal planes are aligned in the direction normal to the substrate plane. Using the 3ω method, we show that voBN exhibits high anisotropic thermal conductivity (TC) with a 16-fold difference between through-film TC and in-plane TC (respectively 4.26 and 0.26 W·m-1·K-1). Molecular dynamics simulations also concurred with the experimental data, showing that the origin of this anisotropic behavior is due to the nature of voBN's plane ordering. While the consistent vertical ordering provides an uninterrupted and preferred propagation path for phonons in the through-film direction, discontinuity in the lateral direction leads to a reduced in-plane TC. In addition, we also use COMSOL to simulate how the dielectric and thermal properties of voBN enable an increase in hot spot density up to 295% compared with SiO2, without any temperature increase.

  19. nBn based infrared detectors using type-II InAs/(In,Ga)Sb superlattices

    Science.gov (United States)

    Plis, E.; Kim, H. S.; Rodriguez, J. B.; Bishop, G. D.; Sharma, Y. D.; Khoshakhlagh, A.; Dawson, L. R.; Bundas, J.; Cook, R.; Burrows, D.; Dennis, R.; Patnaude, K.; Reisinger, A.; Sundaram, M.; Krishna, S.

    2008-04-01

    The development of type-II InAs/(In,Ga)Sb superlattice (SL) detectors with nBn design for single-color and dual-color operation in MWIR and LWIR spectral regions are discussed. First, a 320 x 256 focal plane array (FPA) with cutoff wavelength of 4.2 μm at 77K with average value of dark current density equal to 1 x 10 -7 A/cm2 at V b=0.7V (77 K) is reported. FPA reveals NEDT values of 23.8 mK for 16.3 ms integration time and f/4 optics. At 77K, the peak responsivity and detectivity of FPA are estimated, respectively, to be 1.5 A/W and 6.4 x 10 11 Jones, at 4 μm. Next, implementation of the nBn concept on design of SL LWIR detectors is presented. The fabrication of single element nBn based long wave infrared (LWIR ) with λ c ~ 8.0 μm at V b = +0.9 V and T = 100K detectors are reported. The bias dependent polarity can be exploited to obtain two color response (λ c1 ~ 3.5 μm and λ c2 ~ 8.0 μm) under different polarity of applied bias. The design and fabrication of this two color detector is presented. The dual band response (λ c1 ~ 4.5 μm and λ c2 ~ 8 μm) is achieved by changing the polarity of applied bias. The spectral response cutoff wavelength shifts from MWIR to LWIR when the applied bias voltage varies within a very small bias range (~100 mV).

  20. Overexpression of sinapine esterase BnSCE3 in oilseed rape seeds triggers global changes in seed metabolism.

    Science.gov (United States)

    Clauss, Kathleen; von Roepenack-Lahaye, Edda; Böttcher, Christoph; Roth, Mary R; Welti, Ruth; Erban, Alexander; Kopka, Joachim; Scheel, Dierk; Milkowski, Carsten; Strack, Dieter

    2011-03-01

    Sinapine (O-sinapoylcholine) is the predominant phenolic compound in a complex group of sinapate esters in seeds of oilseed rape (Brassica napus). Sinapine has antinutritive activity and prevents the use of seed protein for food and feed. A strategy was developed to lower its content in seeds by expressing an enzyme that hydrolyzes sinapine in developing rape seeds. During early stages of seedling development, a sinapine esterase (BnSCE3) hydrolyzes sinapine, releasing choline and sinapate. A portion of choline enters the phospholipid metabolism, and sinapate is routed via 1-O-sinapoyl-β-glucose into sinapoylmalate. Transgenic oilseed rape lines were generated expressing BnSCE3 under the control of a seed-specific promoter. Two distinct single-copy transgene insertion lines were isolated and propagated to generate homozygous lines, which were subjected to comprehensive phenotyping. Sinapine levels of transgenic seeds were less than 5% of wild-type levels, whereas choline levels were increased. Weight, size, and water content of transgenic seeds were significantly higher than those of wild-type seeds. Seed quality parameters, such as fiber and glucosinolate levels, and agronomically important traits, such as oil and protein contents, differed only slightly, except that amounts of hemicellulose and cellulose were about 30% higher in transgenic compared with wild-type seeds. Electron microscopic examination revealed that a fraction of the transgenic seeds had morphological alterations, characterized by large cavities near the embryonic tissue. Transgenic seedlings were larger than wild-type seedlings, and young seedlings exhibited longer hypocotyls. Examination of metabolic profiles of transgenic seeds indicated that besides suppression of sinapine accumulation, there were other dramatic differences in primary and secondary metabolism. Mapping of these changes onto metabolic pathways revealed global effects of the transgenic BnSCE3 expression on seed metabolism.

  1. Testing of the dual slab verification detector for attended measurements of the BN-350 dry storage casks

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Peter A [Los Alamos National Laboratory; Browne, Michael C [Los Alamos National Laboratory; Williams, Richard B [Los Alamos National Laboratory; Parker, Robert F [Los Alamos National Laboratory

    2009-01-01

    The Dual Slab Verification Detector (DSVD) has been developed and built by Los Alamos National Laboratory in cooperation with the International Atomic Energy Agency (IAEA) as part of the dry storage safeguards system for the spent fuel from the BN-350 fast reactor. The detector consists of two rows of {sup 3}He tubes embedded in a slab of polyethylene which has been designed to be placed on the outer surface of the dry storage cask. The DSVD will be used to perform measurements of the neutron flux emanating from inside the dry storage cask at several locations around each cask to establish a neutron 'fingerprint' that is sensitive to the contents of the cask. The sensitivity of the fingerprinting technique to the removal of specific amount of nuclear material from the cask is determined by the characteristics of the detector that is used to perform the measurements, the characteristics of the spent fuel being measured, and systematic uncertainties that are associated with the dry storage scenario. MCNPX calculations of the BN-350 dry storage asks and layout have shown that the neutron fingerprint verification technique using measurements from the DSVD would be sensitive to both the amount and location of material that is present within an individual cask. To confirm the performance of the neutron fingerprint technique in verifying the presence of BN-350 spent fuel in dry storage, an initial series of measurements have been performed to test the performance and characteristics of the DSVD. Results of these measurements will be presented and compared with MCNPX results.

  2. Extended line defects in BN, GaN, and AlN semiconductor materials: Graphene-like structures

    Science.gov (United States)

    Camacho-Mojica, Dulce C.; López-Urías, Florentino

    2016-05-01

    The extended line defect (ELD) mimicking grain boundaries in two-dimensional systems is theoretically investigated in BN, GaN, and AlN semiconductor materials with a single layer honeycomb structure. The ELD consists of octagonal-square membered rings. Density functional calculations of the electronic density of states, scanning tunneling microscopy and transmission electron microscopy image simulations are analyzed. Our results revealed that the ELDs are stable in all considered monolayers. In addition, electronic density of states calculations demonstrated that in gap states are emerged when ELD is incorporated into the honeycomb structures. Finally, results on armchair nanoribbons with bare-edges and hydrogenated edges are discussed.

  3. Low sub-threshold swing realization with contacts of graphene/h-BN/MoS2 heterostructures in MoS2 transistors

    Science.gov (United States)

    Li, Chao; Yan, Xiao; Bao, Wenzhong; Ding, Shijin; Zhang, David Wei; Zhou, Peng

    2017-11-01

    MoS2 and other atomically thin-layered semiconductors have attracted intensive interest for their unique characteristics and have become promising candidates for short-channel transistor devices. In this work, we demonstrate an MoS2 transistor with a graphene/hBN/MoS2 heterostructure contact so as to achieve a low sub-threshold swing (SS) and expand the scope of the drain current with a low SS. By inserting an h-BN tunneling layer between graphene and MoS2, the carrier transport with a tunneling effect across h-BN makes the transistor exhibit a less than 80 mV/dec sub-threshold swing over 4 orders of magnitude of the drain current at room temperature. Meanwhile, the MoS2 transistor achieves a maximum on/off ratio of ˜107, and the heterostructure contact shows fairly good ohmic characteristics. Furthermore, the thickness of the h-BN tunneling layer in the heterostructure is optimized, which is essential for the tunneling current and the performance of an MoS2 transistor. This study of an MoS2 transistor based on a graphene/h-BN/MoS2 heterostructure contact may pave the way for the development of thin-layered semiconductors in low-power electronic applications.

  4. Decolorization and detoxification of Synozol red HF-6BN azo dye, by Aspergillus niger and Nigrospora sp

    Directory of Open Access Journals (Sweden)

    Sidra Ilyas

    2013-01-01

    Full Text Available In the present investigation the fungi, Aspergillus niger and Nigrospora sp. were employed for decolorization of Synazol red HF-6BN. Decolorization study showed that Aspergillus niger and Nigrospora sp. were able to decolorize 88% and 96% Synazol red 6BN, respectively, in 24 days. It was also studied that 86% and 90% Synazol red containing of dye effluent was decolorized by Aspergillus niger and Nigrospora sp. after 28 days of incubation at room temperature. A fungal-based protein with relative molecular mass of 70 kDa was partially purified and examined for enzymatic characteristics. The enzyme exhibited highest activity at temperature ranging from 40-50[degree sign]C and at pH=6.0. The enzyme activity was enhanced in the presence of metal cations. High performance liquid chromatography analysis confirmed that these fungal strains are capable to degrade Synazol red dye into metabolites. No zones of inhibition on agar plates and growth of Vigna radiata in the presence of dye extracted sample, indicated that the fungal degraded dye metabolites are nontoxic to beneficial micro-flora and plant growth. Aspergillus niger and Nigrospora sp. have promising potential in color removal from textile wastewater-containing azo dyes.

  5. Cutting tool performance enhancement by using a B{sub 4}C/BCN/C-BN multilayer system

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano Gaitan, G. [Technological Development Center ASTIN-SENA, Cali (Colombia); Group of Corrosion and Protection, University of Antioquia, Medellin (Colombia); Caicedo, J.C. [Technological Development Center ASTIN-SENA, Cali (Colombia); Excellence Center for Novel Materials, Universidad del Valle, Cali (Colombia); Prieto, P. [Excellence Center for Novel Materials, Universidad del Valle, Cali (Colombia); Balogh, Adam G. [Institute of Materials Science, Darmstadt University of Technology (Germany)

    2007-07-01

    Thin films of B{sub 4}C/BCN/c-BN multilayers were deposited on to AISI M2 high speed steel substrates by rf. (13.56 MHz) multi-target magnetron sputtering from high purity (99.99%) h-BN and a (99.5%)B{sub 4}C target, in Ar(90%)/N{sub 2}(10%) gasmixture. For their deposition we varied the bias voltage of the B{sub 4}C films between -50 and -250 V and, for the BCN coatings the nitrogen gas flow from 3% to 12%. A 300-nm thick TiN buffer layer was first deposited to improve the adhesion of all samples. Mechanical properties like hardness, elastic Young modulus, and adhesion were determined by nanoindentation and scratch measurements. Finally, cutting tools were carried out. Tool performance was registered as functions of bilayer numbers showed enhancement between 60% and 107% and a surface roughness reduction of 60% for cutting tools coated with 16 bilayers, compared to uncoated tools. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Experimental study of microstructure, mechanical and tribological properties of cBN particulates SS316 alloy based MMCs fabricated by DMLS technique

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, M.; Mandal, V.; Singh, P. K.; Kumar, P.; Kumar, V.; Das, A. K. [Indian Institute of Technology (ISM), Dhanbad (India)

    2017-06-15

    Direct metal laser sintering process (DMLS) was chosen to develop cBN particulates reinforced SS316 based Metal matrix composite (MMC) with 5 %, 7.5 % and 10 % cBN in the nitrogen gas atmosphere using continuous wave fibre laser of 400 W output capacity. Effects of process parameters such as laser power, beam scanning speed and the mixing ratio of powder on different physical properties of the developed MMC were investigated. It was found that the physical and mechanical properties such as friction and wear behavior, micro hardness and density come up with improved results. FESEM images indicate the microstructure of the composite and evidently confirms the presence of cubic boron nitride in the SS316 matrix where chromium nitride acted as a binder in the presence of nitrogen atmosphere. The Vickers hardness values of the developed MMCs with laser power 60 W and 65 W were found in the range of 276-478 HV{sub 0}.2 and 297-460 HV{sub 0}.2, respectively. It was found that Vickers hardness is directly proportional to the % of cBN in the powder mixture and the laser beam power. The wear resistance of the sintered MMCs increased with increasing cBN content in powder mixture and re- sults show that wear of MMCs are much lower than that of SS316. X-Ray diffraction (XRD) analysis of the fabricated MMC confirms the presence of different phases such as cBN, CrN, CrB{sub 2}, Cr{sub 2}N and Fe{sub 3}N as a consequence of a series of chemical reaction between cBN and different elements of SS316 in nitrogen atmosphere.

  7. The Mass1frings mutation underlies early onset hearing impairment in BUB/BnJ mice, a model for the auditory pathology of Usher syndrome IIC

    Science.gov (United States)

    Johnson, K.R.; Zheng, Q.Y.; Weston, M.D.; Ptacek, L.J.; Noben-Trauth, K.

    2010-01-01

    The human ortholog of the gene responsible for audiogenic seizure susceptibility in Frings and BUB/BnJ mice (mouse gene symbol Mass1) recently was shown to underlie Usher syndrome type IIC (USH2C). Here we report that the Mass1frings mutation is responsible for the early onset hearing impairment of BUB/BnJ mice. We found highly significant linkage of Mass1 with ABR threshold variation among mice from two backcrosses involving BUB/BnJ mice with mice of strains CAST/EiJ and MOLD/RkJ. We also show an additive effect of the Cdh23 locus in modulating the progression of hearing loss in backcross mice. Together, these two loci account for more than 70% of the total ABR threshold variation among the backcross mice at all ages. The modifying effect of the strain-specific Cdh23ahl variant may account for the hearing and audiogenic seizure differences observed between Frings and BUB/BnJ mice, which share the Mass1frings mutation. During postnatal cochlear development in BUB/BnJ mice, stereocilia bundles develop abnormally and remain immature and splayed into adulthood, corresponding with the early onset hearing impairment associated with Mass1frings. Progressive base–apex hair cell degeneration occurs at older ages, corresponding with the age-related hearing loss associated with Cdh23ahl. The molecular basis and pathophysiology of hearing loss suggest BUB/BnJ and Frings mice as models to study cellular and molecular mechanisms underlying USH2C auditory pathology. PMID:15820310

  8. BnLATE, a Cys2/His2-Type Zinc-Finger Protein, Enhances Silique Shattering Resistance by Negatively Regulating Lignin Accumulation in the Silique Walls of Brassica napus.

    Science.gov (United States)

    Tao, Zhangsheng; Huang, Yi; Zhang, Lida; Wang, Xinfa; Liu, Guihua; Wang, Hanzhong

    2017-01-01

    Silique shattering resistance is one of the most important agricultural traits in oil crop breeding. Seed shedding from siliques prior to and during harvest causes devastating losses in oilseed yield. Lignin biosynthesis in the silique walls is thought to affect silique-shattering resistance in oil crops. Here, we identified and characterized B. napus LATE FLOWERING (BnLATE), which encodes a Cys2/His2-type zinc-finger protein. Heterologous expression of BnLATE under the double enhanced CaMV 35S promoter (D35S) in wild-type Arabidopsis plants resulted in a marked decrease in lignification in the replum, valve layer (carpel) and dehiscence zone. pBnLATE::GUS activity was strong in the yellowing silique walls of transgenic lines. Furthermore, the expression pattern of BnLATE and the lignin content gradient in the silique walls at 48 days after pollination (DAP) of 73290, a B. napus silique shattering-resistant line, are similar to those in transgenic Arabidopsis lines expressing BnLATE. Transcriptome sequencing of the silique walls revealed that genes encoding peroxidases, which polymerize monolignols and lignin in the phenylpropanoid pathway, were down-regulated at least two-fold change in the D35S::BnLATE transgenic lines. pBnLATE::BnLATE transgenic lines were further used to identify the function of BnLATE, and the results showed that lignification in the carpel and dehiscence zone of yellowing silique also remarkably decreased compared with the wild-type control, the silique shattering-resistance and expression pattern of peroxidase genes are very similar to results with D35S::BnLATE. These results suggest that BnLATE is a negative regulator of lignin biosynthesis in the yellowing silique walls, and promotes silique-shattering resistance in B. napus through restraining the polymerization of monolignols and lignin.

  9. BnLATE, a Cys2/His2-Type Zinc-Finger Protein, Enhances Silique Shattering Resistance by Negatively Regulating Lignin Accumulation in the Silique Walls of Brassica napus.

    Directory of Open Access Journals (Sweden)

    Zhangsheng Tao

    Full Text Available Silique shattering resistance is one of the most important agricultural traits in oil crop breeding. Seed shedding from siliques prior to and during harvest causes devastating losses in oilseed yield. Lignin biosynthesis in the silique walls is thought to affect silique-shattering resistance in oil crops. Here, we identified and characterized B. napus LATE FLOWERING (BnLATE, which encodes a Cys2/His2-type zinc-finger protein. Heterologous expression of BnLATE under the double enhanced CaMV 35S promoter (D35S in wild-type Arabidopsis plants resulted in a marked decrease in lignification in the replum, valve layer (carpel and dehiscence zone. pBnLATE::GUS activity was strong in the yellowing silique walls of transgenic lines. Furthermore, the expression pattern of BnLATE and the lignin content gradient in the silique walls at 48 days after pollination (DAP of 73290, a B. napus silique shattering-resistant line, are similar to those in transgenic Arabidopsis lines expressing BnLATE. Transcriptome sequencing of the silique walls revealed that genes encoding peroxidases, which polymerize monolignols and lignin in the phenylpropanoid pathway, were down-regulated at least two-fold change in the D35S::BnLATE transgenic lines. pBnLATE::BnLATE transgenic lines were further used to identify the function of BnLATE, and the results showed that lignification in the carpel and dehiscence zone of yellowing silique also remarkably decreased compared with the wild-type control, the silique shattering-resistance and expression pattern of peroxidase genes are very similar to results with D35S::BnLATE. These results suggest that BnLATE is a negative regulator of lignin biosynthesis in the yellowing silique walls, and promotes silique-shattering resistance in B. napus through restraining the polymerization of monolignols and lignin.

  10. Comparison of B{sub 2}O{sub 3} and BN deposited by atomic layer deposition for forming ultrashallow dopant regions by solid state diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Consiglio, Steven, E-mail: steve.consiglio@us.tel.com; Clark, Robert D.; O' Meara, David; Wajda, Cory S.; Tapily, Kandabara; Leusink, Gert J. [TEL Technology Center, America, LLC, 255 Fuller Rd., Albany, New York 12203 (United States)

    2016-01-15

    In this study, the authors investigated atomic layer deposition (ALD) of B{sub 2}O{sub 3} and BN for conformal, ultrashallow B doping applications and compared the effect of dopant-containing overlayers on sheet resistance (R{sub s}) and B profiles for both types of films subjected to a drive-in thermal anneal. For the deposition of B{sub 2}O{sub 3}, tris(dimethylamido)borane and O{sub 3} were used as coreactants and for the deposition of BN, BCl{sub 3} and NH{sub 3} were used as coreactants. Due to the extreme air instability of B{sub 2}O{sub 3} films, physical analysis was performed on B{sub 2}O{sub 3} films, which were capped in-situ with ∼30 Å ALD grown Al{sub 2}O{sub 3} layers. For the BN films, in-situ ALD grown Si{sub 3}N{sub 4} capping layers (∼30 Å) were used for comparison. From spectroscopic ellipsometry, a thickness decrease was observed after 1000 °C, 30 s anneal for the B{sub 2}O{sub 3} containing stack with 60 ALD cycles of B{sub 2}O{sub 3}, whereas the BN containing stacks showed negligible thickness decrease after the annealing step, regardless of the number of BN cycles tested. The postanneal reduction in film thickness as well as decrease in R{sub s} for the B{sub 2}O{sub 3} containing stack suggests that the solid state diffusion dopant mechanism is effective, whereas for the BN containing stacks this phenomenon seems to be suppressed. Further clarification of the effectiveness of the B{sub 2}O{sub 3} containing layer compared to the film stacks with BN was evidenced in backside secondary ion mass spectrometry profiling of B atoms. Thus, B{sub 2}O{sub 3} formed by an ALD process and subsequently capped in-situ followed by a drive-in anneal offers promise as a dopant source for ultrashallow doping, whereas the same method using BN seems ineffective. An integrated approach for B{sub 2}O{sub 3} deposition and annealing on a clustered tool also demonstrated controllable R{sub s} reduction without the use of a capping layer.

  11. nBn structure based on InAs /GaSb type-II strained layer superlattices

    Science.gov (United States)

    Rodriguez, J. B.; Plis, E.; Bishop, G.; Sharma, Y. D.; Kim, H.; Dawson, L. R.; Krishna, S.

    2007-07-01

    The authors report on a type-II InAs /GaSb strained layer superlattice (SLS) photodetector using an nBn design that can be used to eliminate both Shockley-Read-Hall generation currents and surface recombination currents, leading to a higher operating temperature. We present such a SLS based structure with a cutoff wavelength of 5.2μm at room temperature. Processed devices exhibited a quantum efficiency around 18%, and a shot-noise-limited specific detectivity ˜109Jones at 4.5μm and 300K, which are comparable to the state of the art values reported for p-i-n photodiodes based on strained layer superlattices.

  12. Tuning the piezoelectric and mechanical properties of the AlN system via alloying with YN and BN

    Science.gov (United States)

    Manna, Sukriti; Brennecka, Geoff L.; Stevanović, Vladan; Ciobanu, Cristian V.

    2017-09-01

    Recent advances in microelectromechanical systems often require multifunctional materials, which are designed so as to optimize more than one property. Using density functional theory calculations for alloyed nitride systems, we illustrate how co-alloying a piezoelectric material (AlN) with different nitrides helps tune both its piezoelectric and mechanical properties simultaneously. Wurtzite AlN-YN alloys display increased piezoelectric response with YN concentration, accompanied by mechanical softening along the crystallographic c direction. Both effects increase the electromechanical coupling coefficients relevant for transducers and actuators. Resonator applications, however, require superior stiffness, thus leading to the need to decouple the increased piezoelectric response from the softened lattice. We show that co-alloying of AlN with YN and BN results in improved elastic properties while retaining some of the piezoelectric enhancements from YN alloying. This finding may lead to new avenues for tuning the design properties of piezoelectrics through composition-property maps.

  13. Resonant quantum efficiency enhancement of midwave infrared nBn photodetectors using one-dimensional plasmonic gratings

    Energy Technology Data Exchange (ETDEWEB)

    Nolde, Jill A., E-mail: jill.nolde@nrl.navy.mil; Kim, Chul Soo; Jackson, Eric M.; Ellis, Chase T.; Abell, Joshua; Glembocki, Orest J.; Canedy, Chadwick L.; Tischler, Joseph G.; Vurgaftman, Igor; Meyer, Jerry R.; Aifer, Edward H. [Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States); Kim, Mijin [Sotera Defense Solutions, Inc., 7230 Lee Deforest Dr. Suite 100, Columbia, Maryland 21046 (United States)

    2015-06-29

    We demonstrate up to 39% resonant enhancement of the quantum efficiency (QE) of a low dark current nBn midwave infrared photodetector with a 0.5 μm InAsSb absorber layer. The enhancement was achieved by using a 1D plasmonic grating to couple incident light into plasmon modes propagating in the plane of the device. The plasmonic grating is composed of stripes of deposited amorphous germanium overlaid with gold. Devices with and without gratings were processed side-by-side for comparison of their QEs and dark currents. The peak external QE for a grating device was 29% compared to 22% for a mirror device when the illumination was polarized perpendicularly to the grating lines. Additional experiments determined the grating coupling efficiency by measuring the reflectance of analogous gratings deposited on bare GaSb substrates.

  14. Translation and pilot validation of Hindi translation of assessing quality of life in patients with primary brain tumours using EORTC brain module (BN-20

    Directory of Open Access Journals (Sweden)

    Budrukkar Ashwini

    2006-01-01

    Full Text Available Aim: To translate and validate the European Organisation for Research and Treatment for Cancer (EORTC brain cancer module (BN-20 into Hindi to make it available for patients and scientific community. Methods and Results: The EORTC BN-20 was translated into Hindi using standard guidelines by EORTC. The process included forward translation by two translators, discussion with the translators in case of discrepancies and formation of first intermediate questionnaire. This questionnaire was then given to two more translators who translated this questionnaire back into English. These 2 questionnaires were then compared with the original EORTC questionnaire and the second intermediate questionnaire was formed. The second intermediate questionnaire was subsequently administered in 10 patients with brain tumors who had never seen the questionnaire before, for pilot-testing. Each of these 10 patients after filling up the questionnaire themselves was then interviewed for any difficulty encountered during the filling up of the questionnaire. These were in the form of specific modules including difficulty in answering, confusion while answering and difficulty to understand, whether the questions were upsetting and if patients would have asked the question in any different way. There were major suggestions in three questions, which were incorporated into the second intermediate questionnaire to form the final Hindi BN-20 questionnaire. Conclusion: The final Hindi BN-20 has been approved by EORTC and can be used in clinical practice and studies for patients with brain tumors.

  15. Translation and pilot validation of Hindi translation of assessing quality of life in patients with primary brain tumours using EORTC brain module (BN-20).

    Science.gov (United States)

    Budrukkar, Ashwini; Jalali, Rakesh; Kamble, Rashmi; Parab, Sachin

    2006-01-01

    To translate and validate the European Organisation for Research and Treatment for Cancer (EORTC) brain cancer module (BN-20) into Hindi to make it available for patients and scientific community. The EORTC BN-20 was translated into Hindi using standard guidelines by EORTC. The process included forward translation by two translators, discussion with the translators in case of discrepancies and formation of first intermediate questionnaire. This questionnaire was then given to two more translators who translated this questionnaire back into English. These 2 questionnaires were then compared with the original EORTC questionnaire and the second intermediate questionnaire was formed. The second intermediate questionnaire was subsequently administered in 10 patients with brain tumors who had never seen the questionnaire before, for pilot-testing. Each of these 10 patients after filling up the questionnaire themselves was then interviewed for any difficulty encountered during the filling up of the questionnaire. These were in the form of specific modules including difficulty in answering, confusion while answering and difficulty to understand, whether the questions were upsetting and if patients would have asked the question in any different way. There were major suggestions in three questions, which were incorporated into the second intermediate questionnaire to form the final Hindi BN-20 questionnaire. The final Hindi BN-20 has been approved by EORTC and can be used in clinical practice and studies for patients with brain tumors.

  16. Large-Scale Synthesis of Few-Layer F-BN Nanocages with Zigzag-Edge Triangular Antidot Defects and Investigation of the Advanced Ferromagnetism.

    Science.gov (United States)

    Si, Haibin; Lian, Gang; Wang, Aizhu; Cui, Deliang; Zhao, Mingwen; Wang, Qilong; Wong, Ching-Ping

    2015-12-09

    Investigation of light-element magnetism system is essential in fundamental and practical fields. Here, few-layer (∼3 nm) fluorinated hexagonal boron nitride (F-BN) nanocages with zigzag-edge triangular antidot defects were synthesized via a facile one-step solid-state reaction. They are free of metallic impurities confirmed by X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and inductively coupled plasma atomic emission spectroscopy. Ferromagnetism is obviously observed in the BN nanocages. Saturation magnetization values of them differed by less than 7% between 5 and 300 K, indicating that the Curie temperature (Tc) was much higher than 300 K. By adjusting the concentration of triangular antidot defects and fluorine dopants, the ferromagnetic performance of BN nanocages could be effectively varied, indicating that the observed magnetism originates from triangular antidot defects and fluorination. The corresponding theoretical calculation shows that antidot defects and fluorine doping in BN lattice both favor spontaneous spin polarization and the formation of local magnetic moment, which should be responsible for long-range magnetic ordering in the sp material.

  17. Crystal structures of 2-(N,N-dimethylaminoalkyl)ferroceneboronic acids and their diol derivatives. The quest for a B-N intramolecular bond in the solid state

    DEFF Research Database (Denmark)

    Norrild, Jens Chr.; Søtofte, Inger

    2001-01-01

    ,N-dimethylaminomethyl)ferroceneboronate (5) are presented. In connection with our studies of boronic acid-based carbohydrate sensors, we aimed at verifying the existence of an intramolecular B-N bond in these compounds; however, such a bond was not found. This fact, and other structural elements and similarities of the four compounds...

  18. Influence of modulation period and modulation ratio on structure and mechanical properties of TiBN/CrN coatings deposited by multi-arc ion plating

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, S.Y.; Yan, S.J.; Han, B. [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, 430072 Wuhan (China); Yang, B. [School of Power and Mechanical Engineering, Wuhan University, 430072 Wuhan (China); Lin, B.Z.; Zhang, Z.D.; Ai, Z.W. [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, 430072 Wuhan (China); Pelenovich, V.O. [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, 430072 Wuhan (China); Institute of Ion-Plasma and Laser Technologies, Academy of Sciences of Uzbekistan, 700135 Tashkent (Uzbekistan); Fu, D.J., E-mail: djfu@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-Materials of Ministry of Education and School of Physics and Technology, Wuhan University, 430072 Wuhan (China)

    2015-10-01

    Highlights: • TiBN/CrN multilayers were synthesized with varied modulation period and ratio. • The maximum hardness of 38.6 GPa is observed at Λ = 11.7 nm and R = 5:1. • The lowest multilayer COF of 0.32 is lower than that of CrN (0.56). • The wear rate of the coatings is improved and related to H/E and H{sup 3}/E{sup *2} ratios. - Abstract: TiBN/CrN multilayered superlattice coatings with modulation periods Λ (bilayer thickness) ranging from 22.5 to 4.2 nm and modulation ratio R (the thickness ratio of CrN and TiBN layers) ranging from 6:1 to 3:1 were synthesized using an industrial-scale cathodic arc ion plating system in an Ar–N{sub 2} gas mixture. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindention were employed to investigate the influence of modulation period and ratio on microstructure and mechanical properties of the multilayers. The sharp interfaces and nanoscale multilayered modulation were confirmed by TEM. TiBN/CrN multilayer coatings were crystallized with orientations at the (1 1 1), (2 0 0) and (2 2 0) crystallographic planes and the microstructure was strengthened at (2 0 0) preferred orientation. The maximum hardness of 38.6 GPa and elastic modulus of 477 GPa were obtained at Λ = 11.7 nm and R = 5:1. The lowest value of the friction coefficient at 0.32 sliding against a WC-Co ball was obtained at a bilayer period of 11.7 nm, compared to those of the coatings with other modulation periods and monolithic coatings. The wear rate of the multilayered coatings was also lower than those of the monolithic CrN and TiBN coatings.

  19. Modulation of interfacial electronic properties in PbI{sub 2} and BN van der Waals heterobilayer via external electric field

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yaqiang [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); Zhao, Xu, E-mail: zhaoxu@htu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); Niu, Mengmeng [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); Dai, Xianqi, E-mail: xqdai@htu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); School of Physics and Electronic Engineering, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Li, Wei [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); Wang, Xiaolong [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); State Key Laboratory of Information Photonics and Optical Communication, Beijing University Posts and Telecommunications, Beijing 100876 (China); Zhao, Mingyu; Wang, Tianxing [College of Physics and Materials Science, Henan Normal University, Xinxiang 453007 (China); Tang, Yanan [School of Physics and Electronic Engineering, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China)

    2017-07-31

    Highlights: • An atomically type-II heterobilayer which is suitable for optoelectronics and solar cell with wide bandgap was formed. • The charge redistribution is mainly on the surface and the amount of electrons depends on the strength of E{sub field}. • The bandgaps varying with E{sub field} can be divided into three ranges indicating different E{sub field}-sensitive which may possess potential in sensor. • Increasing the E{sub field} upon 0.07 V/Å, the band alignment converts from type-II to type-I heterojunction. - Abstract: The interfacial electronic properties of PbI{sub 2} and BN van der Waals (vdW) heterobilayer are explored by using density functional theory (DFT) method. An intrinsic type-II heterostructure with a wide bandgap is demonstrated. The spatial separation of the lowest energy electron-hole pairs can be actualised and make PbI{sub 2}/BN heterostructure as a good candidate for applications in optoelectronics and solar cell. A simulation of E{sub field} is actualized to modify its electronic properties. Band alignment converts from type-II to type-I heterostructure separated by a forward voltage with the value of about 0.07 V/Å. Three regions implying different E{sub field}-sensitive properties are obtained from the variations of bandgap with E{sub field}. The charge redistribution with an E{sub field} is mainly on the surface of PbI{sub 2} and BN layers as well as the amount of electrons depends on the strength of E{sub field}. In addition, the PbI{sub 2}/BN heterobilayer exhibits more outstanding optical conductivity capability. Our results could bring forward a new perspective on sensor and shed light on the design of novel nano- and optoelectronics based on the PbI{sub 2}/BN vdW heterostructure.

  20. Electronic structure, stability and magnetic properties of small M{sub 1–2}Cr (M = Fe, Co, and Ni) alloy encapsulated inside a (BN){sub 48} cage

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Wenjuan [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China); School of Chemistry and Chemical Engineering, Shanxi Datong University, Datong, 037009 (China); Jia, Jianfeng, E-mail: jiajf@dns.sxnu.edu.cn [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China); Lv, Jin; Wu, Haishun [School of Chemistry and Materials Science, Shanxi Normal University, Linfen, 041004 (China)

    2015-09-04

    The geometrical structure and magnetic properties of M{sub 1–2}Cr (M = Fe, Co, and Ni) alloy clusters inside a (BN){sub 48} cage were calculated at the BPW91/LANL2DZ level of theory. The doping with Cr significantly changed the magnetic properties of the transition-metal clusters. When M{sub 1–2}Cr alloys were placed inside a (BN){sub 48} cage, the alloy clusters interacted strongly with the cage, and the M{sub 1–2}Cr@(BN){sub 48} clusters showed high stability. Moreover, Cr-doped magnetic metal clusters preferably occupied positions off-center and near the hexagonal rings of (BN){sub 48} cages. Thus, the (BN){sub 48} cages can be used to increase the stability of M{sub 1–2}Cr alloys, and retain their magnetic nature, except for CoCr and Ni{sub 2}Cr clusters. - Highlights: • Doping with Cr significantly changed the magnetic properties of the transition-metal clusters. • The M{sub 1–2}Cr clusters occupy position off-center and near the hexagonal ring of the (BN){sub 48} cages. • The (BN){sub 48} cages can be used to increase the stability of the small magnetic clusters.

  1. Most effective way to improve the hydrogen storage abilities of Na-decorated BN sheets: applying external biaxial strain and an electric field.

    Science.gov (United States)

    Tang, Chunmei; Zhang, Xue; Zhou, Xiaofeng

    2017-02-15

    Density functional calculations were used to investigate the hydrogen storage abilities of Na-atoms-decorated BN sheets under both external biaxial strain and a vertical electric field. The Na atom generally has the weakest binding strength to a given substrate compared with the other elements in the periodic table [PANS, 2016, 113, 3735]. Consequently, it is understudied in comparison to other elements and there are few reports about the hydrogen storage abilities of Na-decorated nanomaterials. We calculated that the average binding energy (Eb) of Na atoms to the pure BN sheet is 1.08 eV, which is smaller than the cohesive energy of bulk Na (1.11 eV). However, the Eb can be increased to 1.15 eV under 15% biaxial strain, and further up to 1.53 eV with the control of both 15% biaxial strain and a 5.14 V nm(-1) electric field (E-field). Therefore, the application of biaxial strain and an external upward E-field can prevent clustering of the Na atoms on the surface of a BN sheet, which is crucial for the hydrogen storage. Each Na atom on the surface of a BN sheet can adsorb only one H2 molecule when no strain or E-field is applied; however, the absorption increases to five H2 molecules under 15% biaxial strain and six H2 molecules under both 15% biaxial strain combined with a 5.14 V nm(-1)E-field. The average adsorption energies for H2 of BN-(Na-mH2) (m = 1-6) are within the range of practical applications (0.2-0.6 eV). The hydrogen gravimetric density of the periodic BN-(Na-6H2)4 structure is 9 wt%, which exceeds the 5.5 wt% value that should be met by 2017 as specified by the US Department of Energy. On the other side, removal of the biaxial strain and E-field can help to desorb the H2 molecule. These findings suggest a new route to design hydrogen storage materials under near-ambient conditions.

  2. Thermochemistry and electronic structure of small boron clusters (B(n), n = 5-13) and their anions.

    Science.gov (United States)

    Truong, Ba Tai; Grant, Daniel J; Nguyen, Minh Tho; Dixon, David A

    2010-01-21

    Thermochemical parameters of a set of small-sized neutral (B(n)) and anionic (B(n)(-)) boron clusters, with n = 5-13, were determined using coupled-cluster theory CCSD(T) calculations with the aug-cc-pVnZ (n = D, T, and Q) basis sets extrapolated to the complete basis set limit (CBS) plus addition corrections and/or G3B3 calculations. Enthalpies of formation, adiabatic electron affinities (EA), vertical (VDE), and adiabatic (ADE) detachment energies were evaluated. Our calculated EAs are in good agreement with recent experiments (values in eV): B(5) (CBS, 2.29; G3B3, 2.48; exptl., 2.33 +/- 0.02), B(6) (CBS, 2.59; G3B3, 3.23; exptl., 3.01 +/- 0.04), B(7) (CBS, 2.62; G3B3, 2.67; exptl., 2.55 +/- 0.05), B(8) (CBS, 3.02; G3B3, 3.11; exptl., 3.02 +/- 0.02), B(9) (G3B3, 3.03; exptl., 3.39 +/- 0.06), B(10) (G3B3, 2.85; exptl., 2.88 +/- 0.09), B(11) (G3B4, 3.48;, exptl., 3.43 +/- 0.01), B(12) (G3B3, 2.33; exptl., 2.21 +/- 0.04), and B(13) (G3B3, 3.62; exptl., 3.78 +/- 0.02). The difference between the calculated adiabatic electron affinity and the adiabatic detachment energy for B(6) is due to the fact that the geometry of the anion is not that of the ground-state neutral. The calculated adiabatic detachment energies to the (3)A(u), C(2h) and (1)A(g), D(2h) excited states of B(6), which have geometries similar to the (1)A(g), D(2h) state of B(6)(-), are 2.93 and 3.06 eV, in excellent agreement with experiment. The VDEs were also well reproduced by the calculations. Partitioning of the electron localization functions into pi and sigma components allows probing of the partial and local delocalization in global nonaromatic systems. The larger clusters appear to exhibit multiple aromaticity. The binding energies per atom vary in a parallel manner for both neutral and anionic series and approach the experimental value for the heat of atomization of B. The resonance energies and the normalized resonance energies are convenient indices to quantify the stabilization of a cluster

  3. Evaluation of the internalization kinetics of the radiopharmaceutical {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)Lys{sup 3}-Bn with diagnostic purposes, using comet assay; Evaluacion de la cinetica de internalizacion del radiofarmaco {sup 99m}Tc-N{sub 2}S{sub 2}-TAT(49-57)Lys{sup 3}-BN con fines diagnosticos, empleando ensayo cometa

    Energy Technology Data Exchange (ETDEWEB)

    Luna G, M. A.

    2011-07-01

    Gastrin-rea leasing peptide receptors (GRP-r) are over expressed in breast and prostate cancer cells. Bombesin (Bn) binds specifically and strongly to GRP-r and this is the base for to label the Bn with radionuclides by gamma rays. Tat (49-57) is a peptide that across the cell membrane easily so that, when it is conjugated to different proteins, it can works as a Trojan horse, facilitating the drug internalization to the cells. The radiopharmaceutical {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn was prepared for diagnosis and therapy at early stage of breast cancer. The objective of this study was to determine the role of Tat in the internalization kinetics of radiopharmaceuticals measured by DNA damage induced by means of comet assay. Human lymphocytes were treated with the following protocols: a) Tat-Bn, b) {sup 99m}Tc-Bn, or c) {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn, also an untreated group was conformed. The internalization was evaluated at 0, 5, 10, 15, 30 and 60 min after exposure with three repetitions each one, and for radiopharmaceuticals with 2.9, 6.6, 9.0 and 14.8 MBq activities. DNA damage was scored in 100 cells per time and treatment, as tail length and tail moment. A Kruskal-Wallis variance analysis with p{<=} 0.05 was applied for comparison between treatments. The results showed that the damage caused by {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn is significantly higher than that caused by {sup 99m}Tc-Bn and Tat-Bn, showing that Tat favors the internalization of the radiopharmaceutical. (Author)

  4. Effect of platelet-activating factor antagonists (BN-52021, WEB-2170, and BB-882) on bacterial translocation in acute pancreatitis.

    Science.gov (United States)

    de Souza, L J; Sampietre, S N; Assis, R S; Knowles, C H; Leite, K R; Jancar, S; Monteiro Cunha, J E; Machado, M C

    2001-01-01

    Bacterial translocation is an important source of pancreas infection in acute pancreatitis. The effect of platelet-activating factor (PAF) in the pathogenesis of acute pancreatitis has been proved in various studies. The aim of this study was to determine whether potent PAF antagonists influence bacterial translocation in acute pancreatitis. Acute pancreatitis was induced in 62 Wistar rats by injection of 2.5% sodium taurocholate into the biliopancreatic duct. The rats treated with PAF factor antagonists received intravenous injection of WEB-2170 (10 mg/kg), lexipafant (5 mg/kg), and BN-52021 (5 mg/kg) 30 minutes before induction of acute pancreatitis. Six hours after induction of acute pancreatitis, bacteriologic cultures and histologic scoring of tissues were performed. There was a statistically significant reduction in bacterial translocation to the mesenteric lymph nodes and liver but not to the pancreas of the rats treated with PAF antagonists. No significant increase in the intestinal bacterial population of any group was found. There were no statistical differences between the pancreatic histologic scores of the groups. PAF antagonists reduced bacterial translocation to distant sites other than the pancreas, preventing the bacterial dissemination that occurs in the early phase of acute pancreatitis and may have beneficial effects on the evolution of this disease.

  5. Assessing reactor physics codes capabilities to simulate fast reactors on the example of the BN-600 benchmark

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Vladimir [Scientific and Engineering Centre for Nuclear and Radiation Safety (SES NRS), Moscow (Russian Federation); Bousquet, Jeremy [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Garching (Germany)

    2016-11-15

    This work aims to assess the capabilities of reactor physics codes (initially validated for thermal reactors) to simulate fast sodium cooled reactors. The BFS-62-3A critical experiment from the BN-600 Hybrid Core Benchmark Analyses was chosen for the investigation. Monte-Carlo codes (KENO from SCALE and SERPENT 2.1.23) and the deterministic diffusion code DYN3D-MG are applied to calculate the neutronic parameters. It was found that the multiplication factor and reactivity effects calculated by KENO and SERPENT using the ENDF/B-VII.0 continuous energy library are in a good agreement with each other and with the measured benchmark values. Few-groups macroscopic cross sections, required for DYN3D-MG, were prepared in applying different methods implemented in SCALE and SERPENT. The DYN3D-MG results of a simplified benchmark show reasonable agreement with results from Monte-Carlo calculations and measured values. The former results are used to justify DYN3D-MG implementation for sodium cooled fast reactors coupled deterministic analysis.

  6. Void swelling of AISI 321 analog stainless steel irradiated at low dpa rates in the BN-350 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maksimkin, O.P. [Institute of Nuclear Physics, Almaty (Kazakhstan); Tsai, K.V. [Institute of Nuclear Physics, Almaty (Kazakhstan); Turubarova, L.G. [Institute of Nuclear Physics, Almaty (Kazakhstan); Doronina, T. [Institute of Nuclear Physics, Almaty (Kazakhstan); Garner, F.A. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)]. E-mail: frank.garner@pnl.gov

    2007-08-01

    In several recently published studies conducted on a Soviet analog of AISI 321 stainless steel irradiated in either fast reactors or light water reactors, it was shown that the void swelling phenomenon extended to temperatures as low as {approx}300 {sup o}C or less, when produced by neutron irradiation at dpa rates in the range 10{sup -7}-10{sup -8} dpa/s. Other studies yielded similar results for AISI 316 and the Russian analog of AISI 316. In the current study a blanket assembly duct from BN-350, constructed from the Soviet analog of AISI 321, also exhibits swelling at dpa rates on the order of 10{sup -8} dpa/s, with voids seen as low as 281 {sup o}C and only 0.65 dpa. It appears that low-temperature swelling occurs at low dpa rates in 300 series stainless steels in general, and also occurs during irradiations conducted in either fast or in mixed spectrum reactors as shown in other studies.

  7. Ab initio studies of coherent spin transport in Fe-hBN/graphene van der Waals multilayers.

    Science.gov (United States)

    Ukpong, Aniekan Magnus

    2017-07-19

    This paper presents the results of ab initio studies of the electronic spin inversion and filtering in a ferromagnetic multilayer heterostructure. Spin-polarized electronic structure calculations are performed based on van der Waals density functional theory to give unique insights in to the generation, manipulation and transport of coherent spin conductance. By using an exact theory of the self-consistent ground state of the Fe-hBN/graphene multilayer as a model of the magnetic tunnel junction, hidden asymmetries are unraveled in the spin-resolved charge densities. It is shown that the injection of spin into the graphene/boron nitride tunnel layer from a ferromagnetic contact gives rise to coherent spin current. The projected Fermi surfaces of the up and down spin channels are analyzed to reveal Fermi arc topologies and spin anisotropies. It is also demonstrated that the coherent transport of pure spin-down current in the topological Weyl semimetal phase is robust. The implications of the results on out-of-plane transport of spin polarized conductance in van der Waals multilayer spintronic devices is discussed. The insights derived from this study are expected to open up prospects for further exploration of van der Waals magnetic multilayer heterostructures as a versatile platform for developing materials for Weyltronic applications.

  8. Rapid degradation of azo dye Direct Black BN by magnetic MgFe{sub 2}O{sub 4}-SiC under microwave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Jia; Yang, Shaogui, E-mail: yangsg@nju.edu.cn; Li, Na; Meng, Lingjun; Wang, Fei; He, Huan; Sun, Cheng

    2016-08-30

    Highlights: • MgFe{sub 2}O{sub 4}-SiC was first successfully synthesized. • MgFe{sub 2}O{sub 4}-SiC attained the maximum absorbing value of 13.32 dB at 2.57 GHz, which reached extremely high RL value at low frequency range. • Fast decolorization and high TOC removal of azo dye Direct Black BN with complicated structure could occur with MgFe{sub 2}O{sub 4}-SiC under MW radiation. • MgFe{sub 2}O{sub 4}-SiC had better MW absorbing property and higher MW catalytic activity than MnFe{sub 2}O{sub 4}-SiC under the same condition. • MgFe{sub 2}O{sub 4}-SiC was of practical use in the wastewater treatment. - Abstract: A novel microwave (MW) catalyst, MgFe{sub 2}O{sub 4} loaded on SiC (MgFe{sub 2}O{sub 4}-SiC), was successfully synthesized by sol-gel method, and pure MgFe{sub 2}O{sub 4} was used as reference. The MgFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4}-SiC catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), N{sub 2} adsorption analyzer (BET specific surface area), X-ray photoelectron spectroscopy (XPS). The electromagnetic parameters of the prepared catalysts were measured by vector network analyzer. The reflection loss (RL) based on the electromagnetic parameters calculated in Matlab showed MgFe{sub 2}O{sub 4}-SiC attained the maximum absorbing value of 13.32 dB at 2.57 GHz, which reached extremely high RL value at low frequency range, revealing the excellent MW absorption property of MgFe{sub 2}O{sub 4}-SiC. MW-induced degradation of Direct Black BN (DB BN) over as-synthesized MgFe{sub 2}O{sub 4}-SiC indicated that degradation efficiency of DB BN (20 mg L{sup −1}) in 5 min reached 96.5%, the corresponding TOC removal was 65%, and the toxicity of DB BN after degradation by MgFe{sub 2}O{sub 4}-SiC obviously decreased. The good stability and applicability of MgFe{sub 2}O{sub 4}-SiC on the degradation process were also discovered. Moreover, the ionic chromatogram during degradation

  9. Mid-infrared InAs/GaSb strained layer superlattice detectors with nBn design grown on a GaAs substrate

    Science.gov (United States)

    Plis, E.; Rodriguez, J. B.; Balakrishnan, G.; Sharma, Y. D.; Kim, H. S.; Rotter, T.; Krishna, S.

    2010-08-01

    We report on a type-II InAs/GaSb strained layer superlattice (SLS) photodetector (λ_cut\\-off ~4.3 µm at 77 K) with nBn design grown on a GaAs substrate using interfacial misfit dislocation arrays to minimize threading dislocations in the active region. At 77 K and 0.1 V of the applied bias, the dark current density was equal to 6 × 10-4 A cm-2 and the maximum specific detectivity D* was estimated to 1.2 × 1011 Jones (at 0 V). At 293 K, the zero-bias D* was found to be ~109 Jones which is comparable to the nBn InAs/GaSb SLS detector grown on the GaSb substrate.

  10. Thermodynamic Analysis about Nucleation and Growth of Cubic Boron Nitride Crystals in the hBN-Li3N System under High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Xiao-Fei Guo

    2015-02-01

    Full Text Available The nucleation of cubic boron nitride (cBN single crystals synthesized with lithium nitride (Li3N as a catalyst under high pressure and high temperature (HPHT was analyzed. Many nanometer-sized cubic boron nitride nuclei formed in the near surface layer, as detected by high resolution transmission electron microscopy. Based on the experiment results, the transformation kinetics is described by a nucleation and growth process in the thermodynamic stability region of cBN. A theoretical description is developed based on the heterogeneous nucleation and layer growth mechanism, and the relevant parameters are estimated and discussed. The critical crystal radius, r*, increases with the temperature under constant pressure; the change with temperature more pronounced at lower pressure (such as 4.5 GPa. The crystal growth velocity increased with the temperature, and it is parabolic with temperature under certain pressure. These results are consistent with experimental data.

  11. The passive nondestructive assay of the plutonium content of spent-fuel assemblies from the BN-350 fast-breeder reactor in the city of Aqtau, Kazakhstan

    CERN Document Server

    Lestone, J P; Rennie, J A; Sprinkle, J K; Staples, P; Grimm, K N; Hill, R N; Cherradi, I; Islam, N; Koulikov, J; Starovich, Z

    2002-01-01

    The International Atomic Energy Agency is presently interested in developing equipment and techniques to measure the plutonium content of breeder reactor spent-fuel assemblies located in storage ponds before they are relocated to more secure facilities. We present the first quantitative nondestructive assay of the plutonium content of fast-breeder reactor spent-fuel assemblies while still underwater in their facility storage pond. We have calibrated and installed an underwater neutron coincidence counter (Spent Fuel Coincidence Counter (SFCC)) in the BN-350 reactor spent-fuel pond in Aqtau, Kazakhstan. A procedure has been developed to convert singles and doubles (coincidence) neutron rates observed by the SFCC into the total plutonium content of a given BN-350 spent-fuel assembly. The plutonium content has been successfully determined for spent-fuel assemblies with a contact radiation level as high as approx 10 sup 5 Rads/h. Using limited facility information and multiple measurements along the length of spe...

  12. Promising Approach for High-Performance MoS2 Nanodevice: Doping the BN Buffer Layer to Eliminate the Schottky Barriers.

    Science.gov (United States)

    Su, Jie; Feng, Li-Ping; Zheng, Xiaoqi; Hu, Chenlu; Lu, Hongcheng; Liu, Zhengtang

    2017-11-07

    Reducing the Schottky barrier height (SBH) of metal-MoS2 interface with no deteriorating the intrinsic properties of MoS2 channel layer is crucial to realize the high-performance MoS2 nanodevice. To realize this expectation, a promising approach is present in this study by doping the boron nitride (BN) buffer layer between metal electrode and MoS2 channel layer. Results demonstrate that no matter the types of concentrations and dopants the intrinsic electronic structure, low electron effective mass of MoS2 channel layer, and the weak Fermi level pinning effects of metal/BN-MoS2 interfaces are preserved and not deteriorated. More importantly, the n- and p-type SBHs of metal/BN-MoS2 interfaces are significantly reduced by the electron-poor and -rich dopants, respectively, when the doped BN buffer layer spreads all over the nanodevice, which is in contrast to the traditional doping rule. Moreover, both the n- and p-type SBHs are further decreased and even eliminated when the concentrations of dopants increase. The n-type SBH of doped Au/BxN-MoS2 interface and the p-type SBH of doped Pt/BNx-MoS2 interface can be reduced to -0.21 and -0.61 eV by doping with high concentrations of Li and O, respectively. This theoretical work provides an effective and promising method to realize high-performance MoS2 nanodevices with negligible SBHs.

  13. In the male brown-Norway (BN) male rat, reproductive aging is associated with decreased LH-pulse amplitude and area.

    Science.gov (United States)

    Bonavera, J J; Swerdloff, R S; Leung, A; Lue, Y H; Baravarian, S; Superlano, L; Sinha-Hikim, A P; Wang, C

    1997-01-01

    The Brown-Norway (BN) rat has been proposed as a rodent model for the study of human male reproductive aging. As in man, reduction in serum or plasma testosterone (T) and both testicular (primary) and hypothalamic-pituitary (secondary) reproductive dysfunction have been associated with aging in male BN rats. However, the presence of secondary testicular failure in this rodent, as indicated by low serum luteinizing hormone (LH) levels, needs further corroboration. The present study was designed to determine whether age-related differences in the pulsatile patterns of pituitary LH and follicle-stimulating hormone (FSH) secretion occur in gonad-intact male BN rats. Three age groups were examined: young (3-4 months), middle aged (12-13 months), and old (21-22 months). Using intra-atrial cannulae, serial 5-minute blood samples were withdrawn from conscious, unrestrained animals. Plasma LH concentrations were determined by a supersensitive immunofluorometric assay (FIA) and FSH and T by radioimmunoassay (RIA). Mean T levels were different among groups (young > middle age > old). In young rats, T levels were higher in the late morning/early afternoon than in the late afternoon: this variation was not found in older rats. Mean FSH concentrations were higher in the old than in the middle-aged and young rats. Significant differences in mean LH levels were not found among groups. Compared to young rats, shortened pulse interval and reduced area of pulses characterized the secretory pattern of both gonadotropins in old rats. In addition, LH-pulse amplitude and total area of LH pulses were also significantly lower in old than in young rats. Besides the well-recognized primary testicular failure that occurs in the old BN rat, this study confirms a hypothalamic-pituitary deficiency that makes this rodent model ideal for studying human male reproductive aging.

  14. Preparation and characterization of reactively sintered Ni{sub 3}Al-hBN-Ag composite coating on Ni-based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

    2009-04-03

    Ni{sub 3}Al-hBN-Ag intermetallic matrix composite coating was prepared on Ni-based superalloy by reactive sintering. The crystalline phase and microstructure of the coating were examined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results showed that the hBN particles pretreated by electroless nickel plating and hot-dip aluminizing and Ag particles with a size of several micrometers were homogeneously dispersed in the Ni{sub 3}Al matrix, and the composite coating had strong interfacial bonding with a fine and dense microstructure. During the reactive sintering, an exothermic reaction between Ni and Al associated with a transient liquid phase occurred, leading to in situ synthesis of the densified Ni{sub 3}Al matrix in the coating with a high tensile strength of more than 70 MPa. The high-temperature tribological properties evaluated on a ball-on-disc test rig showed that the coating possessed self-lubricating properties from room temperature to 800 deg. C due to a synergetic lubricating action of Ag and hBN.

  15. Silencing of BnTT1 family genes affects seed flavonoid biosynthesis and alters seed fatty acid composition in Brassica napus.

    Science.gov (United States)

    Lian, Jianping; Lu, Xiaochun; Yin, Nengwen; Ma, Lijuan; Lu, Jing; Liu, Xue; Li, Jiana; Lu, Jun; Lei, Bo; Wang, Rui; Chai, Yourong

    2017-01-01

    TRANSPARENT TESTA1 (TT1) is a zinc finger protein that contains a WIP domain. It plays important roles in controlling differentiation and pigmentation of the seed coat endothelium, and can affect the expression of early biosynthetic genes and late biosynthetic genes of flavonoid biosynthesis in Arabidopsis thaliana. In Brassica napus (AACC, 2n=38), the functions of BnTT1 genes remain unknown and few studies have focused on their roles in fatty acid (FA) biosynthesis. In this study, BnTT1 family genes were silenced by RNA interference, which resulted in yellow rapeseed, abnormal testa development (a much thinner testa), decreased seed weight, and altered seed FA composition in B. napus. High-throughput sequencing of genes differentially expressed between developing transgenic B. napus and wild-type seeds revealed altered expression of numerous genes involved in flavonoid and FA biosynthesis. As a consequence of this altered expression, we detected a marked decrease of oleic acid (C18:1) and notable increases of linoleic acid (C18:2) and α-linolenic acid (C18:3) in mature transgenic B. napus seeds by gas chromatography and near-infrared reflectance spectroscopy. Meanwhile, liquid chromatography-mass spectrometry showed reduced accumulation of flavonoids in transgenic seeds. Therefore, we propose that BnTT1s are involved in the regulation of flavonoid biosynthesis, and may also play a role in FA biosynthesis in B. napus. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Optimization of wear loss in silicon nitride (Si3N4)-hexagonal boron nitride (hBN) composite using DoE-Taguchi method.

    Science.gov (United States)

    Ghalme, Sachin; Mankar, Ankush; Bhalerao, Y J

    2016-01-01

    The contacting surfaces subjected to progressive loss of material known as 'wear,' which is unavoidable between contacting surfaces. Similar kind of phenomenon observed in the human body in various joints where sliding/rolling contact takes place in contacting parts, leading to loss of material. This is a serious issue related to replaced joint or artificial joint. Out of the various material combinations proposed for artificial joint or joint replacement Si3N4 against Al2O3 is one of in ceramic on ceramic category. Minimizing the wear loss of Si3N4 is a prime requirement to avoid aseptic loosening of artificial joint and extending life of joint. In this paper, an attempt has been made to investigate the wear loss behavior of Si3N4-hBN composite and evaluate the effect of hBN addition in Si3N4 to minimize the wear loss. DoE-Taguchi technique is used to plan and analyze experiments. Analysis of experimental results proposes 15 N load and 8 % of hBN addition in Si3N4 is optimum to minimize wear loss against alumina.

  17. Processing and Structural Advantages of the Sylramic-iBN SiC Fiber for SiC/SiC Components

    Science.gov (United States)

    Yun, H. M.; Dicarlo, J. A.; Bhatt, R. T.; Hurst, J. B.

    2008-01-01

    The successful high-temperature application of complex-shaped SiC/SiC components will depend on achieving as high a fraction of the as-produced fiber strength as possible during component fabrication and service. Key issues center on a variety of component architecture, processing, and service-related factors that can reduce fiber strength, such as fiber-fiber abrasion during architecture shaping, surface chemical attack during interphase deposition and service, and intrinsic flaw growth during high-temperature matrix formation and composite creep. The objective of this paper is to show that the NASA-developed Sylramic-iBN SiC fiber minimizes many of these issues for state-of-the-art melt-infiltrated (MI) SiC/BN/SiC composites. To accomplish this, data from various mechanical tests are presented that compare how different high performance SiC fiber types retain strength during formation of complex architectures, during processing of BN interphases and MI matrices, and during simulated composite service at high temperatures.

  18. Microstructure and Tensile Properties of BN/SiC Coated Hi-Nicalon, and Sylramic SiC Fiber Preforms. Revised

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Chen, Yuan L.; Morscher, Gregory N.

    2002-01-01

    Batch to batch and within batch variations, and the influence of fiber architecture on room temperature physical and tensile properties of BN/SiC coated Hi-Nicalon and Sylramic SiC fiber preform specimens were determined. The three fiber architectures studied were plain weave (PW), 5-harness satin (5HS), and 8-harness satin (8HS). Results indicate that the physical properties vary up to 10 percent within a batch, and up to 20 percent between batches of preforms. Load-reload (Hysteresis) and acoustic emission methods were used to analyze damage accumulation occurring during tensile loading. Early acoustic emission activity, before observable hysteretic behavior, indicates that the damage starts with the formation of nonbridged tunnel cracks. These cracks then propagate and intersect the load bearing "0 deg" fibers giving rise to hysteretic behavior. For the Hi-Nicalon preform specimens, the onset of "0 deg" bundle cracking stress and strain appeared to be independent of the fiber architecture. Also, the "0 deg" fiber bundle cracking strain remained nearly the same for the preform specimens of both fiber types. TEM analysis indicates that the CVI BN interface coating is mostly amorphous and contains carbon and oxygen impurities, and the CVI SiC coating is crystalline. No reaction exists between the CVI BN and SiC coating.

  19. Synthesis and characterization of Ni60-hBN high temperature self-lubricating anti-wear composite coatings on Ti6Al4V alloy by laser cladding

    Science.gov (United States)

    Lu, Xiao-Long; Liu, Xiu-Bo; Yu, Peng-Cheng; Qiao, Shi-Jie; Zhai, Yong-Jie; Wang, Ming-Di; Chen, Yao; Xu, Dong

    2016-04-01

    Ni60-hBN composite coatings with varying hBN content were prepared on Ti6Al4V substrates by laser cladding. The composite coatings with no cracks and few pores are bonded metallurgically with the substrates. The phase composition and microstructure of the composite coatings were investigated. The tribological properties of the composite coatings were evaluated under dry sliding wear test conditions at 20 °C, 300 °C and 600 °C, respectively. The microhardness gradually increased from the bottom to the top of the coating and increased with increasing of hBN content. The laser clad Ni60-10%hBN coating exhibits excellent tribological behavior at high temperatures (300 °C and 600 °C).

  20. Metal-free ferromagnetic metal and intrinsic spin semiconductor: two different kinds of SWCNT functionalized BN nanoribbons.

    Science.gov (United States)

    Lou, Ping

    2015-03-28

    Two different kinds of SWCNT functionalized zigzag edge BN nanoribbons with n chains (n-ZBNNRs), namely, (a) B-edge functionalized by (m,m)SWCNT and N-edge modified with H (nZBNNR-B-(m,m)SWCNTs); and (b) the B-edge modified with H and the N-edge functionalized by (m,m)SWCNT (nZBNNR-N-(m,m)SWCNTs), have been predicted. Amazingly, we find that unlike the semiconducting and nonmagnetic H-modified n-ZBNNRs, the nZBNNR-B-(m,m)SWCNTs are intrinsic ferromagnetic metals, regardless of ribbon widths n and tube diameters (m,m). At a given (m,m), their local magnetic moments, at first, exhibit oscillation with increasing n, whereas when n is larger than 5, they are independent of n. In contrast, unlike the metallic and nonmagnetic (m,m)SWCNTs, the nZBNNR-N-(m,m)SWCNTs are ferromagnetic intrinsic spin-semiconductors with direct band gaps, regardless of n and (m,m). Their local magnetic moments and band gaps are independent of n and (m,m). The DFT calculations reveal that the process of SWCNT functionalization of the n-ZBNNRs does not need any activation energy. Moreover, the formation energies of the SWCNT functionalized n-ZBNNRs are always less than zero. Therefore, the SWCNT functionalized n-ZBNNRs are not only stable, but can also be spontaneously formed. Furthermore, compared with n-ZBNNRs, the SWCNT functionalized n-ZBNNRs show significant improvements in their thermal and mechanical stabilities. Thus, (m,m)SWCNT functionalization of n-ZBNNRs may open new routes toward practical nanoelectronic and optoelectronic as well as spintronic devices based on BNC-based materials.

  1. Using ion beams to tune the nanostructure and optical response of co-deposited Ag : BN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Toudert, J [Laboratoire de Metallurgie Physique, UMR CNRS 6630, Batiment SP2MI, Boulevard Marie et Pierre Curie, Teleport 2 Futuroscope, 86962 Chasseneuil (France); Babonneau, D [Laboratoire de Metallurgie Physique, UMR CNRS 6630, Batiment SP2MI, Boulevard Marie et Pierre Curie, Teleport 2 Futuroscope, 86962 Chasseneuil (France); Camelio, S [Laboratoire de Metallurgie Physique, UMR CNRS 6630, Batiment SP2MI, Boulevard Marie et Pierre Curie, Teleport 2 Futuroscope, 86962 Chasseneuil (France); Girardeau, T [Laboratoire de Metallurgie Physique, UMR CNRS 6630, Batiment SP2MI, Boulevard Marie et Pierre Curie, Teleport 2 Futuroscope, 86962 Chasseneuil (France); Yubero, F [Instituto de Ciencia de Materiales de Sevilla, CSIC, Isla de la Cartuja, 41092 Isla de la Cartuja, Sevilla (Spain); Espinos, J P [Instituto de Ciencia de Materiales de Sevilla, CSIC, Isla de la Cartuja, 41092 Isla de la Cartuja, Sevilla (Spain); Gonzalez-Elipe, A R [Instituto de Ciencia de Materiales de Sevilla, CSIC, Isla de la Cartuja, 41092 Isla de la Cartuja, Sevilla (Spain)

    2007-08-07

    The present study is devoted to co-deposited Ag : BN nanocermet thin films and is focused on the influence of ion irradiation conditions on their structural and linear optical properties. Ion irradiation was performed in situ during the growth of the nanocermets using a 50 eV assistance beam (nitrogen/argon or nitrogen-ion assistance) and ex situ on as-grown films using a 120 keV argon-ion beam (post-irradiation). Grazing incidence small-angle x-ray scattering measurements show that (i) as-grown N-assisted films contain prolate spheroidal clusters (height-to-diameter ratio H/D {approx} 1.8), (ii) N/Ar-ion assistance leads to the formation of more elongated clusters (H/D {approx} 2.1) and (iii) post-irradiation leads to a decrease of H/D to a value close to 1. These results are discussed on the basis of atomic diffusion processes involved during the growth of the nanocermets and during the post-irradiation. The optical transmittance spectra of these films measured at normal incidence display one absorption band, due to the excitation of the (1,1) plasmon mode of the clusters. In the case of the as-grown films, an additional band appears at oblique incidence for P-polarized light, as a consequence of the excitation of the (1,0) plasmon mode of the clusters. Our results show that the spectral position of the absorption bands (which can be tuned in the 400-600 nm range) depends on the H/D ratio of the clusters, in good agreement with calculations of optical transmittance considering the nanocomposite layer as a uniaxial anisotropic medium whose dielectric tensor is described by an anisotropic Maxwell-Garnett model.

  2. Influence of bacteriocins produced by Lactobacillus plantarum BN in the shelf-life of refrigerated bovine meat Influência de bacteriocinas produzidas por Lactobacillus plantarum BN na vida útil de carne bovina refrigerada

    Directory of Open Access Journals (Sweden)

    Ângela M. Fiorentini

    2001-03-01

    Full Text Available Sugar cane molasses is a cheap by-product of the sugar cane industry. This product was used for growth and production of bacteriocins by Lactobacillus plantarum BN and evaluated for its potential application in the extension of the shelf-life of raw meat. Bovine meat cubes were dipped in the filtered and neutralized supernatant of the fermented broth (Treatment A and stored at 5ºC. Counts of psychrotrophic and mesophilic aerobic microorganisms, pH determination and total acidity were performed on meat cubes after 0, 3, 6, 9, 12 and 15 days. These determinations were also done in cubes dipped in a 6% lactic acid solution (treatment B and distilled water (treatment C. After 3 days, the counts of psychrotrophic microorganisms in cubes submitted to treatment A, B and C increased 0.38, 1.42 and 2.04 log cycles, respectively. The same happened with mesophilic microorganisms (0.31, 0.33 and 1.04 log cycles increases, respectively. On the sixth day, the psychrotrophic population in samples submitted to treatments A and B were 2.07 and 0.64 log cycles, respectively, lower than in the control samples (treatment C. Mesophilic microorganisms in these samples were 1.58 and 1.12 log cycles, respectively, lower than the controls. On the sixth day, only samples submitted to treatment A presented lower counts than those recommended by ICMSF as quality standards for raw meat (Melaço de cana de açúcar é um sub-produto barato da indústria açucareira. Esse produto foi empregado para o crescimento e produção de bacteriocina de Lactobacillus plantarum BN e avaliado quando a sua aplicação potencial no aumento da vida útil de carne crua. Cubos de carne bovina foram imersos por 5 minutos no sobrenadante filtrado e neutralizado dessa cultura (Tratamento A e mantidos a 5ºC. Contagens de microrganismos psicrotróficos e mesófilos, determinação de pH e de acidez total foram realizadas nas amostras após 0, 3, 6, 9, 12 e 15 dias. Essas determinações foram

  3. Overexpression of Sinapine Esterase BnSCE3 in Oilseed Rape Seeds Triggers Global Changes in Seed Metabolism1[W][OA

    Science.gov (United States)

    Clauß, Kathleen; von Roepenack-Lahaye, Edda; Böttcher, Christoph; Roth, Mary R.; Welti, Ruth; Erban, Alexander; Kopka, Joachim; Scheel, Dierk; Milkowski, Carsten; Strack, Dieter

    2011-01-01

    Sinapine (O-sinapoylcholine) is the predominant phenolic compound in a complex group of sinapate esters in seeds of oilseed rape (Brassica napus). Sinapine has antinutritive activity and prevents the use of seed protein for food and feed. A strategy was developed to lower its content in seeds by expressing an enzyme that hydrolyzes sinapine in developing rape seeds. During early stages of seedling development, a sinapine esterase (BnSCE3) hydrolyzes sinapine, releasing choline and sinapate. A portion of choline enters the phospholipid metabolism, and sinapate is routed via 1-O-sinapoyl-β-glucose into sinapoylmalate. Transgenic oilseed rape lines were generated expressing BnSCE3 under the control of a seed-specific promoter. Two distinct single-copy transgene insertion lines were isolated and propagated to generate homozygous lines, which were subjected to comprehensive phenotyping. Sinapine levels of transgenic seeds were less than 5% of wild-type levels, whereas choline levels were increased. Weight, size, and water content of transgenic seeds were significantly higher than those of wild-type seeds. Seed quality parameters, such as fiber and glucosinolate levels, and agronomically important traits, such as oil and protein contents, differed only slightly, except that amounts of hemicellulose and cellulose were about 30% higher in transgenic compared with wild-type seeds. Electron microscopic examination revealed that a fraction of the transgenic seeds had morphological alterations, characterized by large cavities near the embryonic tissue. Transgenic seedlings were larger than wild-type seedlings, and young seedlings exhibited longer hypocotyls. Examination of metabolic profiles of transgenic seeds indicated that besides suppression of sinapine accumulation, there were other dramatic differences in primary and secondary metabolism. Mapping of these changes onto metabolic pathways revealed global effects of the transgenic BnSCE3 expression on seed metabolism. PMID

  4. Cykl apokaliptycznych egzegez wizji proroka Daniela w kontekście doktrynalnego sporu wschodniego chrześcijaństwa z judaizmem (na materiale kodeksu BN 12245

    Directory of Open Access Journals (Sweden)

    Jan Stradomski

    2017-10-01

    Full Text Available Series of eschatological exegeses in prophet Daniel’s visions in the context of the doctrinal dispute of Eastern Christianity and Judaism (about the manuscript BN 12245 The Bible’s Book of Daniel, along with commentaries of St. Hippolytus of Rome, belongs to the most important sources of Christian knowledge about the end of the world and the Final Judgment. In the medieval Old Church Slavonic literature, the Book of Daniel functions not only as a part of the Old Testament canon (separately or with comments, but it is also present in historiography, and in particular in apocryphal literature. Prophet Daniel and his vision of four beasts are also the basis for preparation of new eschatological texts where the threads of the doctrinal dispute with Judaism are noticeable. Such writings include a series of visions of Prophet Daniel with commentaries, rarely encountered in Cyrillic manuscripts, featured in Codex BN 12245. The article presents a textological, historical and literary analysis of the text.   Cykl apokaliptycznych egzegez wizji proroka Daniela w kontekście doktrynalnego sporu wschodniego chrześcijaństwa z judaizmem (na materiale kodeksu BN 12245 Biblijna Księga Daniela, wraz z komentarzami św. Hipolita Rzymskiego, należy do ważniejszych źródeł wiedzy chrześcijan na temat końca świata i Sądu Ostatecznego. W średniowiecznej literaturze cerkiewnosłowiańskiej materiał Księgi Daniela funkcjonuje nie tylko jako część korpusu kanonicznych pism Starego Testamentu (osobno lub z komentarzami, ale obecny jest też w historiografii, a zwłaszcza w literaturze apokryficznej. Postać proroka Daniela i jego wizja czterech bestii są też bazą opracowywania nowych tekstów o tematyce eschatologicznej, w których widoczne są wątki doktrynalnego sporu z judaizmem. Do takich pism zalicza się rzadko spotykany w rękopisach cyrylickich cykl komentowanych wizji proroka Daniela, jaki znajduje się w kodeksie BN 12245. W artykule

  5. Interlayer Excitons and Band Alignment in MoS2/hBN/WSe2 van der Waals Heterostructures

    DEFF Research Database (Denmark)

    Latini, Simone; Winther, Kirsten Trøstrup; Olsen, Thomas

    2017-01-01

    van der Waals heterostructures (vdWH) are ideal systems for exploring light-matter interactions at the atomic scale. In particular, structures with a type-II band alignment can yield detailed insight into carrier-photon conversion processes, which are central to, for example, solar cells and light...... of bilayer MoS2/WSe2 with and without intercalated hBN layers, finding excellent agreement with experimental photoluminescence spectra. A comparison to density functional theory calculations demonstrates the crucial role of self-energy and electron-hole interaction effects....

  6. BN interphase in composite materials with nicalon Si-C-O fibers and with vitro ceramic matrix of MAS type; L`interphase BN dans les materiaux composites a fibres Si-C-O nicalon et a matrice vitroceramique de type MAS

    Energy Technology Data Exchange (ETDEWEB)

    Ricca, N.

    1994-03-14

    BN has been suggested as an interphase in silica-based glass-ceramic matrix composites with a view to use these materials in oxidizing atmospheres at medium or high temperatures. The matrix had a boron-doped MAS (MgO-Al{sub 2}O{sub 3}-SiO{sub 2}) composition and was prepared from an hydrosol precursor. Pseudo-ID composites were prepared according to a sol impregnations/calcination/hot-pressing route. Chemical and microstructural characterizations of the fiber/matrix interfacial area were conducted by mean of TEM/EELS and AES analyses. The efficiency of BN as a coupling interphase for this particular composite system was successfully demonstrated through tensile tests performed on either as-processed or aged specimens (100 hours at 1000 deg C in air or under argon). In addition, composites maintained in air at 600 deg C, 800 deg C and 900 deg C while simultaneously loaded did not fail after 150 hours or more. Thus, a BN interphase appeared to be compatible with an oxidizing environment (i.e. the oxide matrix and/or air from 600 to 1000 deg C) and should therefore successfully replace the usual carbon interphase at least for use at medium temperatures. (author)

  7. The direct exchange mechanism of induced spin polarization of low-dimensional π-conjugated carbon- and h-BN fragments at LSMO(001) MnO-terminated interfaces

    Science.gov (United States)

    Kuklin, Artem V.; Kuzubov, Alexander A.; Kovaleva, Evgenia A.; Lee, Hyosun; Sorokin, Pavel B.; Sakai, Seiji; Entani, Shiro; Naramoto, Hiroshi; Avramov, Paul

    2017-10-01

    Induced spin polarization of π-conjugated carbon and h-BN low dimensional fragments at the interfaces formed by deposition of pentacene molecule and narrow zigzag graphene and h-BN nanoribbons on MnO2-terminated LSMO(001) thin film was studied using GGA PBE+U PAW D3-corrected approach. Induced spin polarization of π-conjugated low-dimensional fragments is caused by direct exchange with Mn ions of LSMO(001) MnO-derived surface. Due to direct exchange, the pentacene molecule changes its diamagnetic narrow-band gap semiconducting nature to the ferromagnetic semiconducting state with 0.15 eV energy shift between spin-up and spin-down valence bands and total magnetic moment of 0.11 μB. Direct exchange converts graphene nanoribbon to 100% spin-polarized half-metal with large amplitude of spin-up electronic density at the Fermi level. The direct exchange narrows the h-BN nanoribbon band gap from 4.04 to 1.72 eV in spin-up channel and converts the h-BN ribbon semiconducting diamagnetic nature to a semiconducting magnetic one. The electronic structure calculations demonstrate a possibility to control the spin properties of low-dimensional π-conjugated carbon and h-BN fragments by direct exchange with MnO-derived LSMO(001) surface for spin-related applications.

  8. Ethylene response factor BnERF2-like (ERF2.4 from Brassica napus L. enhances submergence tolerance and alleviates oxidative damage caused by submergence in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yanyan Lv

    2016-06-01

    Full Text Available Ethylene response factor proteins play an important role in regulating a variety of stress responses in plants, but their exact functions in submergence stress are not well understood. In this study, we isolated BnERF2.4 from Brassica napus L. to study its function in submergence tolerance. The expression of the BnERF2.4 gene in B. napus and the expression of antioxidant enzyme genes in transgenic Arabidopsis were analyzed by quantitative RT-PCR. The expression of BnERF2.4 was induced by submergence in B. napus and the overexpression of BnERF2.4 in Arabidopsis increased the level of tolerance to submergence and oxidative stress. A histochemical method detected lower levels of H2O2, O2•− and malondialdehyde (MDA in transgenic Arabidopsis. Compared to the wild type, transgenic lines also had higher soluble sugar content and higher activity of antioxidant enzymes, which helped to protect plants against the oxidative damage caused by submergence. It was concluded that BnERF2.4 increased the tolerance of plants to submergence stress and may be involved in regulating soluble sugar content and the antioxidant system in defense against submergence stress.

  9. Analysis of the attractiveness of materials as applied to the fuel cycle of high-power fast reactor of Bn-type

    Directory of Open Access Journals (Sweden)

    E.M. Lvova

    2016-09-01

    Full Text Available Nuclear fuel cycle of fast reactors contains materials which potentially can be used for fabricating nuclear explosives or nuclear weapons. It is customary to apply to such materials in addressing the problem of non-proliferation of nuclear weapons and nuclear terrorism the concept of attractiveness allowing evaluating potential possibility of their use in clandestine activities. Attractiveness of nuclear materials is evaluated, first of all, according to their neutronics properties. Results are presented of analysis of attractiveness of different types of fuel compositions as applicable to fuel cycle of fast sodium-cooled high-power nuclear reactor of the BN-1200 type for different options of its starting fuel loads and utilized regimes for reaching steady-state fuel composition. The object of the present study were the simplest systems containing fuel compositions of fast reactor of BN-1200 type in the form of bare spherical assemblies without neutron reflector and assemblies surrounded with simplest neutron reflectors. Criticality conditions were determined for each system and main neutronics properties of the fuel compositions under examination were determined for these criticality conditions.

  10. Down-regulation of BnDA1, whose gene locus is associated with the seeds weight, improves the seeds weight and organ size in Brassica napus.

    Science.gov (United States)

    Wang, Jie-Li; Tang, Min-Qiang; Chen, Sheng; Zheng, Xiang-Feng; Mo, Hui-Xian; Li, Sheng-Jun; Wang, Zheng; Zhu, Ke-Ming; Ding, Li-Na; Liu, Sheng-Yi; Li, Yun-Hai; Tan, Xiao-Li

    2017-08-01

    Brassica napus L. is an important oil crop worldwide and is the main raw material for biofuel. Seed weight and seed size are the main contributors to seed yield. DA1 (DA means big in Chinese) is an ubiquitin receptor and negatively regulates seed size. Down-regulation of AtDA1 in Arabidopsis leads to larger seeds and organs by increasing cell proliferation in integuments. In this study, BnDA1 was down-regulated in B. napus by over expressed of AtDA1R358K , which is a functional deficiency of DA1 with an arginine-to-lysine mutation at the 358th amino acid. The results showed that the biomass and size of the seeds, cotyledons, leaves, flowers and siliques of transgenic plants all increased significantly. In particular, the 1000 seed weight increased 21.23% and the seed yield per plant increased 13.22% in field condition. The transgenic plants had no negative traits related to yield. The candidate gene association analysis demonstrated that the BnDA1 locus was contributed to the seeds weight. Therefore, our study showed that regulation of DA1 in B. napus can increase the seed yield and biomass, and DA1 is a promising target for crop improvement. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  11. Self-hardening effect of CrAlN/BN nanocomposite films deposited by direct current and radio frequency reactive cosputtering

    Energy Technology Data Exchange (ETDEWEB)

    Nose, Masateru, E-mail: nose@tad.u-toyama.ac.jp [Faculty of Art and Design, University of Toyama, 180 Futakami, Takaoka-shi, Toyama 933-8588 (Japan); Chiou, Wen-An [NISP Lab., NanoCenter, University of Maryland, College Park, MD 20742-2831 (United States); Kawabata, Tokimasa [School of Science and Engineering, University of Toyama, Toyama-shi, Toyama 930-8555 (Japan); Hatano, Yuji [Hydrogen Isotope Research Center, University of Toyama, Toyama-shi, Toyama 930-8555 (Japan); Matsuda, Kenji [School of Science and Engineering, University of Toyama, Toyama-shi, Toyama 930-8555 (Japan)

    2012-11-15

    A CrAlN/18 vol.% BN nanocomposite film was deposited on substrate by reactive co-sputtering. The films showed an increase of about 30% in indentation hardness and achieved a maximum hardness of approximately 50 GPa after annealing at 800 Degree-Sign C in air. In contrast, the indentation hardness barely changed when the film sample was annealed at 800 Degree-Sign C in nitrogen and argon atmosphere. High-resolution transmission electron microscopy (HRTEM) images revealed that the uppermost layer was characterized by amorphous materials with embedded nanocrystalline particles (occurring at less than {approx} 50 nm below surface). Energy dispersive X-ray spectroscopy (EDS) line profiles of cross-sectional thin films showed a high concentration of oxygen in the uppermost layer of the annealed sample. The indentation hardness of the air-annealed sample was measured by Ar{sup +} ion sputtering before and after etching to the depth at 200 nm from the annealed surface. The hardness decreased from approximately 48 GPa to 43 GPa, which was the same level as the as-deposited films. These results indicate that oxidization of the film surface could be one of the factors responsible for the self-hardening of the CrAlN/BN film.

  12. Negishi Cross-Coupling Is Compatible with a Reactive B-Cl Bond: Development of a Versatile Late-Stage Functionalization of 1,2-Azaborines and Its Application to the Synthesis of New BN Isosteres of Naphthalene and Indenyl.

    Science.gov (United States)

    Brown, Alec N; Li, Bo; Liu, Shih-Yuan

    2015-07-22

    The compatibility of the Negishi cross-coupling reaction with the versatile B-Cl functionality has been demonstrated in the context of late-stage functionalization of 1,2-azaborines. Alkyl-, aryl-, and alkenylzinc reagents have been utilized for the functionalization of the triply orthogonal precursor 3-bromo-1-(tert-butyldimethylsilyl)-2-chloro-1,2-dihydro-1,2-azaborine (2) to furnish new 2,3-substituted monocyclic 1,2-azaborines. This methodology has enabled the synthesis of previously elusive BN-naphthalene and BN-indenyl structures from a common intermediate.

  13. In silico carbon molecular beam epitaxial growth of graphene on the h-BN substrate: carbon source effect on van der Waals epitaxy

    Science.gov (United States)

    Lee, Jonghoon; Varshney, Vikas; Park, Jeongho; Farmer, Barry L.; Roy, Ajit K.

    2016-05-01

    Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon molecular beam epitaxy (CMBE) techniques using solid carbon sublimation have reported relatively poor quality of the graphene. In this article, the CMBE growth of graphene on the h-BN substrate is numerically studied in order to identify the effect of the carbon source on the quality of the graphene film. The carbon molecular beam generated by the sublimation of solid carbon source materials such as graphite and glassy carbon is mostly composed of atomic carbon, carbon dimers and carbon trimers. Therefore, the graphene film growth becomes a complex process involving various deposition characteristics of a multitude of carbon entities. Based on the study of surface adsorption and film growth characteristics of these three major carbon entities comprising graphite vapour, we report that carbon trimers convey strong traits of vdW epitaxy prone to high quality graphene growth, while atomic carbon deposition is a surface-reaction limited process accompanied by strong chemisorption. The vdW epitaxial behaviour of carbon trimers is found to be substantial enough to nucleate and develop into graphene like planar films within a nanosecond of high flux growth simulation, while reactive atomic carbons tend to impair the structural integrity of the crystalline h-BN substrate upon deposition to form an amorphous interface between the substrate and the growing carbon film. The content of reactive atomic carbons in the molecular beam is suspected to be the primary cause of low quality graphene reported in the literature. A possible optimization of the molecular beam composition towards the synthesis of better quality graphene films is suggested.Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon

  14. Mid-IR focal plane array based on type-II InAs /GaSb strain layer superlattice detector with nBn design

    Science.gov (United States)

    Kim, H. S.; Plis, E.; Rodriguez, J. B.; Bishop, G. D.; Sharma, Y. D.; Dawson, L. R.; Krishna, S.; Bundas, J.; Cook, R.; Burrows, D.; Dennis, R.; Patnaude, K.; Reisinger, A.; Sundaram, M.

    2008-05-01

    A midwave infrared camera (λc=4.2μm) with a 320×256 focal plane array (FPA) based on type-II InAs/GaSb strain layer superlattice (SLs) has been demonstrated. The detectors consist of an nBn heterostructure, wherein the SL absorber and contact layers are separated by a Al0.2Ga0.8Sb barrier layer, which is designed to have a minimum valence band offset. Unlike a PN junction, the size of the device is not defined by a mesa etch but confined by the lateral diffusion length of minority carriers. At 77K, the FPA demonstrates a temporal noise equivalent temperature difference (NETD) of 23.8mK (Tint=16.3ms and Vb=0.7V) with a peak quantum efficiency and detectivity at 3.8μm equal to 52% and 6.7×1011 Jones, respectively.

  15. First-principles simulations of chemical reactions in an HCl molecule embedded inside a C or BN nanotube induced by ultrafast laser pulses.

    Science.gov (United States)

    Miyamoto, Yoshiyuki; Zhang, Hong; Rubio, Angel

    2010-12-10

    We show by first-principles simulations that ultrafast laser pulses induce different chemical reactions in a molecule trapped inside a nanotube. A strong laser pulse polarized perpendicular to the tube axis induces a giant bond stretch of an encapsulated HCl molecule in semiconducting carbon nanotube or in a BN nanotube. Depending on the initial orientation of the HCl molecule, the subsequent laser-induced dynamics is different: either complete disintegration or rebonding of the HCl molecule. Radial motion of the nanotube is always observed and a vacancy appears on the tube wall when the HCl is perpendicular to the tube axis. Those results are important to analyze confined nanochemistry and to manipulate molecules and nanostructures encapsulated in organic and inorganic nanotubes.

  16. Optical and XPS studies of BCN thin films by co-sputtering of B{sub 4}C and BN targets

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Adithya, E-mail: adithya@knights.ucf.edu; Sundaram, Kalpathy B.

    2017-02-28

    Highlights: • Wide range of optical band gaps (Eg) are achieved for dual target sputtered BCN films in the range of 1.9 eV−3.7 eV. • Optical band gap (Eg) studies are performed as a function of target powers, gas ratios and deposition temperatures. • Eg is found to increase with N{sub 2}/Ar flow ratios and deposition temperatures. • XPS studies are conducted to ascertain the chemical and bonding characteristics. • XPS showed higher h-BN and B{sub 4}C property at higher N{sub 2}/Ar gas ratios for films deposited at 20 W and 40 W B{sub 4}C power respectively. - Abstract: Boron carbon nitride (BCN) thin films are investigated for their optical properties. BCN, is the unanimous choice for inter-dielectric layer (IDL) in very large scale integration (VLSI) because of its low-k dielectric constant. Optical properties can be tailored as a function of elemental composition, which makes BCN a prospective material in UV-filters and mirrors. Films are deposited by reactive co-sputtering of boroncarbide (B{sub 4}C) and boronnitride (BN) with varying N{sub 2}/Ar gas flow ratio by DC and RF sputtering respectively. XPS studies are performed to deduce the bonding and chemical properties of the BCN thinfilms. Optical band gap (Eg) studies are performed as a result of varying target powers, gas ratios and deposition temperatures. Eg is found to increase with N{sub 2}/Ar flow ratios and deposition temperatures. BCN deposited at 20 W DC exhibited higher band gap range and the highest achieved is 3.7 eV at N{sub 2}/Ar = 0.75. Lowest value achieved is 1.9 eV at N{sub 2}/Ar = 0.25 for as-deposited films.

  17. Chemical segregation in the young protostars Barnard 1b-N and S. Evidence of pseudo-disk rotation in Barnard 1b-S

    Science.gov (United States)

    Fuente, A.; Gerin, M.; Pety, J.; Commerçon, B.; Agúndez, M.; Cernicharo, J.; Marcelino, N.; Roueff, E.; Lis, D. C.; Wootten, H. A.

    2017-10-01

    The extremely young Class 0 object B1b-S and the first hydrostatic core (FSHC) candidate, B1b-N, provide a unique opportunity to study the chemical changes produced in the elusive transition from the prestellar core to the protostellar phase. We present 40″ × 70″ images of Barnard 1b in the 13CO 1 → 0, C18O 1 → 0, NH2D 11,1a→ 10,1s, and SO 32→ 21 lines obtained with the NOEMA interferometer. The observed chemical segregation allows us to unveil the physical structure of this young protostellar system down to scales of 500 au. The two protostellar objects are embedded in an elongated condensation, with a velocity gradient of 0.2-0.4 m s-1 au-1 in the east-west direction, reminiscent of an axial collapse. The NH2D data reveal cold and dense pseudo-disks (R 500 - 1000 au) around each protostar. Moreover, we observe evidence of pseudo-disk rotation around B1b-S. We do not see any signature of the bipolar outflows associated with B1b-N and B1b-S, which were previously detected in H2CO and CH3OH, in any of the imaged species. The non-detection of SO constrains the SO/CH3OH abundance ratio in the high-velocity gas. Based on observations carried out with the IRAM Northern Extended Millimeter Array (NOEMA). IRAM is supported by INSU/ CNRS (France), MPG (Germany), and IGN (Spain).The reduced datacube is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/L3

  18. Biokinetics and dosimetry of a hybrid formulation of {sup 9{sup m}}Tc-BN and {sup 99m}Tc-RGD{sub 2} starting from optic images in a murine model; Biocinetica y dosimetria de una formulacion hibrida de {sup 99m}Tc-BN y {sup 99m}Tc-RGD{sub 2} a partir de imagenes opticas en un modelo murino

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo A, L. G.

    2015-07-01

    This work has the purpose of evaluate the biokinetics and absorbed dose of radiation of hybrid formulation {sup 99m}Tc-BN /{sup 99m}Tc-RGD{sub 2} in a murine model by optical imaging techniques using the multimodal preclinical in vivo image system Xtreme. The used method were the {sup 99m}Tc-BN, {sup 99m}Tc-RGD{sub 2} and {sup 99m}Tc-BN/{sup 99m}Tc-RGD{sub 2} formulas, with specific recognition for GRPr and the integrin s α(v)β(3) and α(v)β(5) respectively, was injected in the vein tail of three nude mousses with induce breast cancer tumors (cell line T-47-D), by the preclinical multimodal imaging system Xtreme (Bruker), optical images in different times was acquired (5, 10, 20 min, 2 and 24 h), using Images Processing Toolbox of MATLAB these images was transform from RGB format to gray scales and sectioned in five independent images corresponding to heart, kidneys, bladder and tumor areas. The intensity of each images was computed in counts per pixel, then those intensities was corrected for background, attenuation and scattering, using different factors for each phenomena previously calculated. Finally the activity values quantified vs time was fitted into a biokinetic model to obtain the disintegrations number and cumulate activities in each organ. With these data the radiation absorbed dose were calculated using MIRD methodology. Results: The number of disintegration and absorbed dose calculated in MBq h/MBq and mGy/MBq, of injected mouse with the {sup 99m}Tc-BN/{sup 99m}Tc-RGD{sub 2} formulation, was: 0.035 ± 0.65 E-02, 0.25 x 10{sub -5} ± 0.46 E-07; 0.393 ± 0.51 E-1, 2.85 E-05 ± 3.7 E-06; 0.306 ± 0.21 E-01, 2.11 E-05 ± 1.45 E-06 and 0.151 ± 0.19 E-01, 1.09 E-05 ± 1.42 E-06 , in heart, kidneys, bladder and tumor, respectively. The number of disintegration obtained in kidneys is comparable to those reported for Trinidad B. 2014 Conclusions: Our results demonstrated that using optical images and a code for image analyses development in MATLAB, could

  19. An international validation study of the EORTC brain cancer module (EORTC QLQ-BN20) for assessing health-related quality of life and symptoms in brain cancer patients

    NARCIS (Netherlands)

    Taphoorn, M.J.B.; Claassens, L.; Aaronson, N.K.; Coens, C.; Mauer, M.; Osoba, D.; Stupp, R.; Mirimanoff, R.O.; van den Bent, M.J.; Bottomley, A.

    2010-01-01

    Aims The psychometric properties of the EORTC QLQ-BN20, a brain cancer-specific HRQOL questionnaire, have been previously determined in an English-speaking sample of patients. This study examined the validity and reliability of the questionnaire in a multi-national, multi-lingual study. Methods

  20. ¹¹¹In-Bn-DTPA-nimotuzumab with/without modification with nuclear translocation sequence (NLS) peptides: an Auger electron-emitting radioimmunotherapeutic agent for EGFR-positive and trastuzumab (Herceptin)-resistant breast cancer.

    Science.gov (United States)

    Fasih, Aisha; Fonge, Humphrey; Cai, Zhongli; Leyton, Jeffrey V; Tikhomirov, Ilia; Done, Susan J; Reilly, Raymond M

    2012-08-01

    Increased expression of epidermal growth factor receptors (EGFR) in breast cancer (BC) is often associated with trastuzumab (Herceptin)-resistant forms of the disease and represents an attractive target for novel therapies. Nimotuzumab is a humanized IgG(1) monoclonal antibody that is in clinical trials for treatment of EGFR-overexpressing malignancies. We show here that nimotuzumab derivatized with benzylisothiocyanate diethylenetriaminepentaacetic acid for labelling with the subcellular range Auger electron-emitter, (111)In and modified with nuclear translocation sequence (NLS) peptides ((111)In-NLS-Bn-DTPA-nimotuzumab) was bound, internalized and transported to the nucleus of EGFR-positive BC cells. Emission of Auger electrons in close proximity to the nucleus caused multiple DNA double-strand breaks which diminished the clonogenic survival (CS) of MDA-MB-468 cells that have high EGFR density (2.4 × 10(6) receptors/cell) to less than 3 %. (111)In-Bn-DTPA-nimotuzumab without NLS peptide modification was sevenfold less effective for killing MDA-MB-468 cells. (111)In-Bn-DTPA-nimotuzumab with/without NLS peptide modification were equivalently cytotoxic to MDA-MB-231 and TrR1 BC cells that have moderate EGFR density (5.4 × 10(5) or 4.2 × 10(5) receptors/cell, respectively) reducing their CS by twofold. MDA-MB-231 cells have intrinsic trastuzumab resistance due to low HER2 density, whereas TrR1 cells have acquired resistance despite HER2 overexpression. Biodistribution and microSPECT/CT imaging revealed that (111)In-NLS-Bn-DTPA-nimotuzumab exhibited more rapid elimination from the blood and lower tumour uptake than (111)In-Bn-DTPA-nimotuzumab. Tumour uptake of the radioimmunoconjugates in mice with MDA-MB-468 xenografts was high (8-16 % injected dose/g) and was blocked by administration of an excess of unlabelled nimotuzumab, demonstrating EGFR specificity. We conclude that (111)In-Bn-DTPA-nimotuzumab with/without NLS peptide modification are promising Auger

  1. Wafer-scale controlled exfoliation of metal organic vapor phase epitaxy grown InGaN/GaN multi quantum well structures using low-tack two-dimensional layered h-BN

    Energy Technology Data Exchange (ETDEWEB)

    Ayari, Taha; Li, Xin; Voss, Paul L.; Ougazzaden, Abdallah, E-mail: aougazza@georgiatech-metz.fr [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Georgia Tech Lorraine, UMI 2958, Georgia Tech-CNRS, 57070 Metz (France); Sundaram, Suresh; El Gmili, Youssef [Georgia Tech Lorraine, UMI 2958, Georgia Tech-CNRS, 57070 Metz (France); Salvestrini, Jean Paul [Georgia Tech Lorraine, UMI 2958, Georgia Tech-CNRS, 57070 Metz (France); Université de Lorraine, LMOPS, EA 4423, 57070 Metz (France)

    2016-04-25

    Recent advances in epitaxial growth have led to the growth of III-nitride devices on 2D layered h-BN. This advance has the potential for wafer-scale transfer to arbitrary substrates, which could improve the thermal management and would allow III-N devices to be used more flexibly in a broader range of applications. We report wafer scale exfoliation of a metal organic vapor phase epitaxy grown InGaN/GaN Multi Quantum Well (MQW) structure from a 5 nm thick h-BN layer that was grown on a 2-inch sapphire substrate. The weak van der Waals bonds between h-BN atomic layers break easily, allowing the MQW structure to be mechanically lifted off from the sapphire substrate using a commercial adhesive tape. This results in the surface roughness of only 1.14 nm on the separated surface. Structural characterizations performed before and after the lift-off confirm the conservation of structural properties after lift-off. Cathodoluminescence at 454 nm was present before lift-off and 458 nm was present after. Electroluminescence near 450 nm from the lifted-off structure has also been observed. These results show that the high crystalline quality ultrathin h-BN serves as an effective sacrificial layer—it maintains performance, while also reducing the GaN buffer thickness and temperature ramps as compared to a conventional two-step growth method. These results support the use of h-BN as a low-tack sacrificial underlying layer for GaN-based device structures and demonstrate the feasibility of large area lift-off and transfer to any template, which is important for industrial scale production.

  2. p-NO2-Bn-H4neunpa and H4neunpa-Trastuzumab: Bifunctional Chelator for Radiometalpharmaceuticals and (111)In Immuno-Single Photon Emission Computed Tomography Imaging.

    Science.gov (United States)

    Spreckelmeyer, Sarah; Ramogida, Caterina F; Rousseau, Julie; Arane, Karen; Bratanovic, Ivica; Colpo, Nadine; Jermilova, Una; Dias, Gemma M; Dude, Iulia; Jaraquemada-Peláez, Maria de Guadalupe; Bénard, François; Schaffer, Paul; Orvig, Chris

    2017-08-16

    Potentially nonadentate (N5O4) bifunctional chelator p-SCN-Bn-H4neunpa and its immunoconjugate H4neunpa-trastuzumab for (111)In radiolabeling are synthesized. The ability of p-SCN-Bn-H4neunpa and H4neunpa-trastuzumab to quantitatively radiolabel (111)InCl3 at an ambient temperature within 15 or 30 min, respectively, is presented. Thermodynamic stability determination with In(3+), Bi(3+), and La(3+) resulted in high conditional stability constant (pM) values. In vitro human serum stability assays have demonstrated both (111)In complexes to have high stability over 5 days. Mouse biodistribution of [(111)In][In(p-NO2-Bn-neunpa)](-), compared to that of [(111)In][In(p-NH2-Bn-CHX-A″-diethylenetriamine pentaacetic acid (DTPA))](2-), at 1, 4, and 24 h shows fast clearance of both complexes from the mice within 24 h. In a second mouse biodistribution study, the immunoconjugates (111)In-neunpa-trastuzumab and (111)In-CHX-A″-DTPA-trastuzumab demonstrate a similar distribution profile but with slightly lower tumor uptake of (111)In-neunpa-trastuzumab compared to that of (111)In-CHX-A″-DTPA-trastuzumab. These results were also confirmed by immuno-single photon emission computed tomography (immuno-SPECT) imaging in vivo. These initial investigations reveal the acyclic bifunctional chelator p-SCN-Bn-H4neunpa to be a promising chelator for (111)In (and other radiometals) with high in vitro stability and also show H4neunpa-trastuzumab to be an excellent (111)In chelator with promising biodistribution in mice.

  3. SU-E-T-66: A Prototype for Couch Based Real-Time Dosimetry in External Beam Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, P [Peter MacCallum Cancer Centre, Bendigo (Australia)

    2015-06-15

    Purpose: The main purpose of this study is to design a prototype for couch-based based real time dosimetry system in external beam radiotherapy Methods: A prototype of 100 ionization chambers was designed on a printed circuit board by etching the copper layer and each ionization chamber was wired to a 50 pin connector. The signals from the two 50 pin connectors collected from the ionization chambers were then transferred to a PXI module from National Instruments. The PXI module houses a current amplifier that amplifies the charge collected from the ionization chamber. The amplified signal is then sent to a digital multimeter module for converting the analog signal to digital signal. A software was designed in labview to read and display the signals obtained from the PXI module. A couch attachment frame was designed to house the 100 ionization chamber module. The frame was fixed underneath the treatment couch for measuring the dose during treatment. Resutls: The ionization chamber based prototype dosimetry was tested for simple radiotherapy treatment fields and found to be a useful device for measuring real time dosimetry at the treatment couch plane. This information could be used to assess the delivered dose to a patient during radiotherapy. It could be used as an invivo dosimeter during radiotherapy. Conclusion: In this study, a prototype for couch based real time dosimetry system was designed and tested. The prototype forms a basis for the development of large scale couch based real time dosimetry system that could be used to perform morning QA prior to treatment, assess real time doses delivered to patient and as a device to monitor the output of the treatment beam. Peter MacCallum Cancer Foundation.

  4. Manufacturing of thin films of boron for the measurement of the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Smilgys, Barbara; Oliveira, Sandro Guedes de; Hadler Neto, Julio Cesar; Vellame, Igor Alencar [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Soares, Cleber Jose; Salim, Leonardo Alfredo [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Coelho, Paulo Rogerio Pinto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2011-07-01

    Full text: The Boron Neutron Capture Therapy (BNCT) is considered to be a possible treatment for different types of aggressive cancers located in areas of difficult access or which already have metastasis. The working principle of this therapy is the selective delivery of a greater amount of boron to the tumor cells than to the healthy ones, followed by the neutron irradiation that will induce the emission of {alpha} particles through the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT reaction. The high energy deposition of the product particles causes the death of the cells and this therapy becomes much effective if the healthy tissue is less exposed to this radiation. The objective of this work is to develop a method for measuring the rate of this reaction by using thin films of boron. We have manufactured thin films with different concentrations of boron deposited on mica and the thin films were exposed to different irradiation time intervals at the reactor IEA-R1 located at IPEN, Sao Paulo. Here we show our first results on the density and uniformity of the thin films, where the detection of the particles is made using plastic track detectors (CR-39) which have their structures damaged by the passage of ions. (author)

  5. Elastic properties of nc-TiN /a-Si3N4 and nc-TiN /a-BN nanocomposite films by surface Brillouin scattering

    Science.gov (United States)

    Manghnani, Murli H.; Tkachev, Sergey N.; Zinin, Pavel V.; Glorieoux, Christ; Karvankova, Pavla; Veprek, Stan

    2005-03-01

    The hardness of nanocomposite (nc) films developed recently appears to reach the hardness of diamond. High hardness is commonly attributed to the granular structure of nanocomposites (Hall-Petch effect) [E. O. Hall, Proc. Phys. Soc. Lond. B 64, 747 (1951); N. J. Petch, J. Iron Steel Inst. 174, 25 (1953)]. However, grain size in nanocomposites is generally small (5-15nm) and falls in the region where the Hall-Petch effect does not apply. The objective of the present study is to report the elastic properties of the superhard nanocomposites determined by means of surface Brillouin scattering (SBS), and to compare the results with those obtained by nanoindentation. Two types of nanocomposite films were studied: nc-TiN /a-Si3N4 and nc-TiN /a-BN. The SBS measurements presented yield values of Young's modulus significantly larger than those obtained from the slope of unloading indentation curve. This discrepancy is attributed to the lack of the validity of the assumptions behind the Sneddon's derivation of the formula used for the calculation of the Young's modulus from the indentation data.

  6. Isolation of thylakoid membrane complexes from rice by a new double-strips BN/SDS-PAGE and bioinformatics prediction of stromal ridge subunits interaction.

    Directory of Open Access Journals (Sweden)

    Jinzhen Shao

    Full Text Available Thylakoid membrane complexes of rice (Oryza sativa L. play crucial roles in growth and crop production. Understanding of protein interactions within the complex would provide new insights into photosynthesis. Here, a new "Double-Strips BN/SDS-PAGE" method was employed to separate thylakoid membrane complexes in order to increase the protein abundance on 2D-gels and to facilitate the identification of hydrophobic transmembrane proteins. A total of 58 protein spots could be observed and subunit constitution of these complexes exhibited on 2D-gels. The generality of this new approach was confirmed using thylakoid membrane from spinach (Spinacia oleracea and pumpkin (Cucurita spp. Furthermore, the proteins separated from rice thylakoid membrane were identified by the mass spectrometry (MS. The stromal ridge proteins PsaD and PsaE were identified both in the holo- and core- PSI complexes of rice. Using molecular dynamics simulation to explore the recognition mechanism of these subunits, we showed that salt bridge interactions between residues R19 of PsaC and E168 of PasD as well as R75 of PsaC and E91 of PsaD played important roles in the stability of the complex. This stromal ridge subunits interaction was also supported by the subsequent analysis of the binding free energy, the intramolecular distances and the intramolecular energy.

  7. Infection of the upper respiratory tract of hamsters by the bovine parainfluenza virus type 3 BN-1 strain expressing enhanced green fluorescent protein.

    Science.gov (United States)

    Ohkura, Takashi; Minakuchi, Moeko; Sagai, Mami; Kokuho, Takehiro; Konishi, Misako; Kameyama, Ken-Ichiro; Takeuchi, Kaoru

    2015-02-01

    Bovine parainfluenza virus type 3 (BPIV3) is an important pathogen associated with bovine respiratory disease complex (BRDC). We have generated a recombinant BPIV3 expressing enhanced green fluorescent protein (rBPIV3-EGFP) based on the BN-1 strain isolated in Japan. After intranasal infection of hamsters with rBPIV3-EGFP, EGFP fluorescence was detected in the upper respiratory tract including the nasal turbinates, pharynx, larynx, and trachea. In the nasal turbinates, rBPIV3-EGFP attained high titers (>10(6) TCID50/g of tissue) 2-4 days after infection. Ciliated epithelial cells in the nasal turbinates and trachea were infected with rBPIV3-EGFP. Histopathological analysis indicated that mucosal epithelial cells in bronchi were shed by 6 days after infection, leaving non-ciliated cells, which may have increased susceptibility to bacterial infection leading to the development of BRDC. These data indicate that rBPIV3-EGFP infection of hamsters is a useful small animal model for studying the development of BPIV3-associated BRDC. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. IRRADIATION CREEP AND SWELLING OF RUSSIAN FERRITIC-MARTENSITIC STEELS IRRADIATED TO VERY HIGH EXPOSURES IN THE BN-350 FAST REACTOR AT 305-335 DEGREES C

    Energy Technology Data Exchange (ETDEWEB)

    Konobeev, Yu V.; Dvoraishin, A. M.; Porollo, S. I.; Shulepin, S. V.; Budylkin, N. I.; Mironova, E. G.; Garner, Francis A.; Toloczko, Mychailo B.

    2003-09-03

    Russian ferritic martensitic (F(slash)M) steels EP(dash)450, EP(dash)852 and EP(dash)823 were irradiated in the BN(dash)350 fast reactor in the form of gas-pressurized creep tubes. The first steel is used in Russia for hexagonal wrappers in fast reactors. The other steels were developed for compatibility with Pb(dash)Bi coolants and serve to enhance our understanding of the general behavior of this class of steels. In an earlier paper we published data on irradiation creep of EP(dash)450 and EP(dash) 823 at temperatures between 390 and 520 degrees C, with dpa levels ranging from 20 to 60 dpa. In the current paper new data on the irradiation creep and swelling of EP(dash)450 and EP(dash)852 at temperatures between 305 and 335 degrees C and doses ranging from 61 to 89 dpa are presented. Where comparisons are possible, it appears that these steels exhibit behavior that is very consistent with that of Western steels. Swelling is relatively low at high neutron exposure and confined to temperatures less then 420 degrees C, but may be camouflaged somewhat by precipitation related densification. These irradiation creep studies confirm that the creep compliance of F(slash)M steels is about one half that of austenitic steels.

  9. Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors

    Science.gov (United States)

    Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; zhao, Ruo; Zou, Ruqiang

    2017-01-01

    To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH)2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH)2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g−1 at a current density of 1A g−1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH)2@CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg−1. This device also exhibits excellent rate capability with energy density of 15.55 Whkg−1 at power density of 9331 Wkg−1 coupled long termed stability up to 6000 cycles. PMID:28240224

  10. Adsorption of carbon dioxide (CO{sub 2}) at S functionalized boron nitride (BN) and aluminum nitride (AlN) nanotubes (9, 0): A quantum chemical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Najafi, Meysam, E-mail: meysamnajafi2016@yahoo.com

    2016-10-30

    Highlights: • AlN-NT has higher potential to CO{sub 2} adsorption in comparison to BN-NT. • S functionalization of studied nanotubes improve the CO{sub 2} adsorption ability of them. • E{sub ad} is suitable scale to propose the novel toxic gas sensor based on nanostructured. • E{sub ad} and E{sub HLG} of studied nanotubes have linear dependences. - Abstract: We employed density functional theory to characterize CO{sub 2} adsorption on BNNT and AlNNT surfaces. The effects of S functionalization on the adsorption of CO{sub 2} gas on BNNT and AlNNT surfaces were investigated. Results reveal that adsorptions of CO{sub 2} on studied nanotubes were exothermic and experimentally possible from the energetic viewpoint. Results show that, E{sub ad} values of CO{sub 2} on AlNNT surface were more negative than corresponding values of BNNT. Results reveal that, S functionalization of studied nanotubes causes an increase in the absolute values of E{sub ad} of CO{sub 2} on surface of studied nanotubes. These results show that, there are good linearity dependencies between E{sub ad} and orbital energy values of studied nanotubes. Therefore we can conclude the E{sub ad} and orbital energy values are highly sensitive to the adsorption process which these may be used for the selection the suitable nanotubes with enhanced CO{sub 2} adsorption potential.

  11. Stark shift and electric-field-induced dissociation of excitons in monolayer MoS2 and h BN /MoS2 heterostructures

    Science.gov (United States)

    Haastrup, Sten; Latini, Simone; Bolotin, Kirill; Thygesen, Kristian S.

    2016-07-01

    Efficient conversion of photons into electrical current in two-dimensional semiconductors requires, as a first step, the dissociation of the strongly bound excitons into free electrons and holes. Here we calculate the dissociation rates and energy shift of excitons in monolayer MoS2 as a function of an applied in-plane electric field. The dissociation rates are obtained as the inverse lifetime of the resonant states of a two-dimensional hydrogenic Hamiltonian which describes the exciton within the Mott-Wannier model. The resonances are computed using complex scaling, and the effective masses and screened electron-hole interaction defining the hydrogenic Hamiltonian are computed from first principles. For field strengths above 0.1 V/nm the dissociation lifetime is shorter than 1 ps, which is below the lifetime associated with competing decay mechanisms. Interestingly, encapsulation of the MoS2 layer in just two layers of hexagonal boron nitride (h BN ), enhances the dissociation rate by around one order of magnitude due to the increased screening. This shows that dielectric engineering is an effective way to control exciton lifetimes in two-dimensional materials.

  12. Ti6Al4V Blade Wear Behavior During High-Speed Rubbing with NiAl-hBN Abradable Seal Coating

    Science.gov (United States)

    Xue, Weihai; Gao, Siyang; Duan, Deli; Zhang, Jiaping; Liu, Yang; Li, Shu

    2017-02-01

    The high-speed rubbing wear behavior between a Ti6Al4V blade and a NiAl-hBN seal coating was studied with a high-speed rub test rig. Blade wear behavior, which had not received enough attentions, was the key concern of this study. The rub tests conducted at different linear speeds and single-pass depths indicated that although wear distance was constant and rub forces decreased at high linear speed, blade wear increased with the increment of linear speed when single-pass depth was invariable. According to scanning electron microscopy, x-ray diffraction, electron probe microanalysis and microhardness analyses of the wear scars, different blade and coating wear mechanisms were observed when rubbed at different linear speeds. Remarkably, when rubbing was done at high linear speed, there was severe blade oxidation with the generation of oxidation layer full of cracks and high-hardness transfer layer in the coating wear scar, and these were identified as reasons of aggravated blade wear.

  13. How a CCA sequence protects mature tRNAs and tRNA precursors from action of the processing enzyme RNase BN/RNase Z.

    Science.gov (United States)

    Dutta, Tanmay; Malhotra, Arun; Deutscher, Murray P

    2013-10-18

    In many organisms, 3' maturation of tRNAs is catalyzed by the endoribonuclease, RNase BN/RNase Z, which cleaves after the discriminator nucleotide to generate a substrate for addition of the universal CCA sequence. However, tRNAs or tRNA precursors that already contain a CCA sequence are not cleaved, thereby avoiding a futile cycle of removal and readdition of these essential residues. We show here that the adjacent C residues of the CCA sequence and an Arg residue within a highly conserved sequence motif in the channel leading to the RNase catalytic site are both required for the protective effect of the CCA sequence. When both of these determinants are present, CCA-containing RNAs in the channel are unable to move into the catalytic site; however, substitution of either of the C residues by A or U or mutation of Arg(274) to Ala allows RNA movement and catalysis to proceed. These data define a novel mechanism for how tRNAs are protected against the promiscuous action of a processing enzyme.

  14. How a CCA Sequence Protects Mature tRNAs and tRNA Precursors from Action of the Processing Enzyme RNase BN/RNase Z*

    Science.gov (United States)

    Dutta, Tanmay; Malhotra, Arun; Deutscher, Murray P.

    2013-01-01

    In many organisms, 3′ maturation of tRNAs is catalyzed by the endoribonuclease, RNase BN/RNase Z, which cleaves after the discriminator nucleotide to generate a substrate for addition of the universal CCA sequence. However, tRNAs or tRNA precursors that already contain a CCA sequence are not cleaved, thereby avoiding a futile cycle of removal and readdition of these essential residues. We show here that the adjacent C residues of the CCA sequence and an Arg residue within a highly conserved sequence motif in the channel leading to the RNase catalytic site are both required for the protective effect of the CCA sequence. When both of these determinants are present, CCA-containing RNAs in the channel are unable to move into the catalytic site; however, substitution of either of the C residues by A or U or mutation of Arg274 to Ala allows RNA movement and catalysis to proceed. These data define a novel mechanism for how tRNAs are protected against the promiscuous action of a processing enzyme. PMID:24022488

  15. Enhancement of thermal transport in Gel Polymer Electrolytes with embedded BN/Al2O3 nano- and micro-particles

    Science.gov (United States)

    Vishwakarma, Vivek; Jain, Ankur

    2017-09-01

    While Gel Polymer Electrolytes (GPEs) have been widely investigated for use in next-generation Li-ion cells due to the potential for improved thermal safety, thermal transport within a GPE is still poorly understood. Among all materials in a Li-ion cell, the GPE has the lowest thermal conductivity, and hence determines the overall rate of heat flow in a Li-ion cell. This makes it critical to measure and understand thermal transport in a GPE and investigate trade-offs between thermal and ionic transport. This paper presents measurements of thermal and ionic conductivities in a PVdF-based GPE. The effect of incorporating BN/Al2O3 ceramic nano/microparticles in the GPE on thermal and ionic transport is characterized. Measurements indicate up to 2.5X improvement in thermal conductivity of activated GPE membranes, with relatively minor effect on electrochemical performance of GPE-based single-layer cells. The measured enhancement in thermal conductivity is in very good agreement with theoretical calculations based on the effective medium theory that accounts for thermal transport in a dispersed, two-phase medium such as a GPE. The fundamental insights gained in this work on thermal transport in a GPE and the role of nano/microparticle inclusions may facilitate thermal-electrochemical optimization and design of GPEs for safe, high-performance Li-ion cells.

  16. KLASİK ESER [DE ANİMA] OKUYUCUSU VE ŞARİHİ OLARAK İBN RÜŞD

    Directory of Open Access Journals (Sweden)

    Atilla ARKAN

    2005-12-01

    Full Text Available İbn Ruchd is one of the important readers and commnetators of Aristotelian philosophicalclassical books. This study, firstly, aims to explain that why Aristotle's De Anima is perceivedas one of main classical book regarding psychology by Muslim philosophers. De Animadetermines basic subjects and problems of psychology and builds explatanory concepts andtheories within logical consistency. Beside that De Anima tries to solve the main problems ofhuman beings such as the meaning of life, freedom, justice and happines. Further, for IbnRuchd, Aristotelian philosophical literature gives the opportunity to establish an harmoniousand consistent human understanding. As a part of this literature, De Anima plays an essentialrole in constructing the relations among God, the nature and human beings.Ibn Ruchd's three commentaries on De Anima are different attemps and examples ofunderstanding and commenting. Therefore, this study tries to determine the characteristicsof these commentaries from the perspective of writing gender and evaluation. Finally thisstudy tries to determine the techniques of Ibn Ruchd which he uses in his commentaries,and general principles which he considers very seriously. Considering these generalprinciples, some of the differences between Aristotle and Ibn Ruchd may be undersoodvery well.

  17. Theranostic pretargeted radioimmunotherapy of colorectal cancer xenografts in mice using picomolar affinity ⁸⁶Y- or ¹⁷⁷Lu-DOTA-Bn binding scFv C825/GPA33 IgG bispecific immunoconjugates.

    Science.gov (United States)

    Cheal, Sarah M; Xu, Hong; Guo, Hong-Fen; Lee, Sang-Gyu; Punzalan, Blesida; Chalasani, Sandhya; Fung, Edward K; Jungbluth, Achim; Zanzonico, Pat B; Carrasquillo, Jorge A; O'Donoghue, Joseph; Smith-Jones, Peter M; Wittrup, K Dane; Cheung, Nai-Kong V; Larson, Steven M

    2016-05-01

    GPA33 is a colorectal cancer (CRC) antigen with unique retention properties after huA33-mediated tumor targeting. We tested a pretargeted radioimmunotherapy (PRIT) approach for CRC using a tetravalent bispecific antibody with dual specificity for GPA33 tumor antigen and DOTA-Bn-(radiolanthanide metal) complex. PRIT was optimized in vivo by titrating sequential intravenous doses of huA33-C825, the dextran-based clearing agent, and the C825 haptens (177)Lu-or (86)Y-DOTA-Bn in mice bearing the SW1222 subcutaneous (s.c.) CRC xenograft model. Using optimized PRIT, therapeutic indices (TIs) for tumor radiation-absorbed dose of 73 (tumor/blood) and 12 (tumor/kidney) were achieved. Estimated absorbed doses (cGy/MBq) to tumor, blood, liver, spleen, and kidney for single-cycle PRIT were 65.8, 0.9 (TI 73), 6.3 (TI 10), 6.6 (TI 10), and 5.3 (TI 12), respectively. Two cycles of PRIT (66.6 or 111 MBq (177)Lu-DOTA-Bn) were safe and effective, with a complete response of established s.c. tumors (100 - 700 mm(3)) in nine of nine mice, with two mice alive without recurrence at >140 days. Tumor log kill in this model was estimated to be 2.1 - 3.0 based on time to 500-mm(3) tumor recurrence. In addition, PRIT dosimetry/diagnosis was performed by PET imaging of the positron-emitting DOTA hapten (86)Y-DOTA-Bn. We have developed anti-GPA33 PRIT as a triple-step theranostic strategy for preclinical detection, dosimetry, and safe targeted radiotherapy of established human colorectal mouse xenografts.

  18. Theranostic pretargeted radioimmunotherapy of colorectal cancer xenografts in mice using picomolar affinity {sup 86}Y- or {sup 177}Lu-DOTA-Bn binding scFv C825/GPA33 IgG bispecific immunoconjugates

    Energy Technology Data Exchange (ETDEWEB)

    Cheal, Sarah M.; Lee, Sang-gyu; Punzalan, Blesida; Larson, Steven M. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Memorial Sloan Kettering Cancer Center, Molecular Pharmacology and Chemistry Program, New York, NY (United States); Xu, Hong; Guo, Hong-fen [Memorial Sloan Kettering Cancer Center, Department of Pediatrics, New York, NY (United States); Chalasani, Sandhya; Carrasquillo, Jorge A. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Fung, Edward K. [Memorial Sloan Kettering Cancer Center, Molecular Pharmacology and Chemistry Program, New York, NY (United States); Memorial Sloan Kettering Cancer Center, Department of Medical Physics, New York, NY (United States); Jungbluth, Achim [Memorial Sloan Kettering Cancer Center, Department of Pathology, New York, NY (United States); Zanzonico, Pat B.; O' Donoghue, Joseph [Memorial Sloan Kettering Cancer Center, Department of Medical Physics, New York, NY (United States); Smith-Jones, Peter M. [Stony Brook University, Department of Psychiatry and Behavioral Science, Stony Brook, NY (United States); Stony Brook University, Department of Radiology, Stony Brook, NY (United States); Wittrup, K.D. [Massachusetts Institute of Technology, Department of Chemical Engineering, Cambridge, MA (United States); Massachusetts Institute of Technology, Department of Biological Engineering, Cambridge, MA (United States); Massachusetts Institute of Technology, Koch Institute for Integrative Cancer Research, Cambridge, MA (United States); Cheung, Nai-Kong V. [Memorial Sloan Kettering Cancer Center, Molecular Pharmacology and Chemistry Program, New York, NY (United States); Memorial Sloan Kettering Cancer Center, Department of Pediatrics, New York, NY (United States)

    2016-05-15

    GPA33 is a colorectal cancer (CRC) antigen with unique retention properties after huA33-mediated tumor targeting. We tested a pretargeted radioimmunotherapy (PRIT) approach for CRC using a tetravalent bispecific antibody with dual specificity for GPA33 tumor antigen and DOTA-Bn-(radiolanthanide metal) complex. PRIT was optimized in vivo by titrating sequential intravenous doses of huA33-C825, the dextran-based clearing agent, and the C825 haptens {sup 177}Lu-or {sup 86}Y-DOTA-Bn in mice bearing the SW1222 subcutaneous (s.c.) CRC xenograft model. Using optimized PRIT, therapeutic indices (TIs) for tumor radiation-absorbed dose of 73 (tumor/blood) and 12 (tumor/kidney) were achieved. Estimated absorbed doses (cGy/MBq) to tumor, blood, liver, spleen, and kidney for single-cycle PRIT were 65.8, 0.9 (TI 73), 6.3 (TI 10), 6.6 (TI 10), and 5.3 (TI 12), respectively. Two cycles of PRIT (66.6 or 111 MBq {sup 177}Lu-DOTA-Bn) were safe and effective, with a complete response of established s.c. tumors (100 - 700 mm{sup 3}) in nine of nine mice, with two mice alive without recurrence at >140 days. Tumor log kill in this model was estimated to be 2.1 - 3.0 based on time to 500-mm{sup 3} tumor recurrence. In addition, PRIT dosimetry/diagnosis was performed by PET imaging of the positron-emitting DOTA hapten {sup 86}Y-DOTA-Bn. We have developed anti-GPA33 PRIT as a triple-step theranostic strategy for preclinical detection, dosimetry, and safe targeted radiotherapy of established human colorectal mouse xenografts. (orig.)

  19. Cross section measurement for the 10B(n ,t 2 α ) three-body reaction at 4.0, 4.5, and 5.0 MeV. I. Prediction of the experimental spectrum

    Science.gov (United States)

    Wang, Zhimin; Bai, Huaiyong; Zhang, Luyu; Jiang, Haoyu; Lu, Yi; Chen, Jinxiang; Zhang, Guohui; Gledenov, Yu. M.; Sedysheva, M. V.; Khuukhenkhuu, G.

    2017-10-01

    Cross sections of the 10B(n ,t 2 α ) three-body reaction were measured at En=4.0 ,4.5 , and 5.0 MeV using a twin gridded ionization chamber and a thin-film 10B sample. The present paper is the first part of the work. The experimental spectrum of the 10B(n ,t 2 α ) reaction measured by the gridded ionization chamber (GIC) was predicted. The 10B(n ,t 2 α ) reaction can proceed in three ways, which are referred to as 7Li**,8Be , and breakup channels. The energies and directional angles of the three particles in the final states for the 7Li**,8Be , and breakup channels were calculated, respectively. Based on these results, the one-dimensional and two-dimensional spectra were calculated through integration. Three kinds of interference reactions were taken into account, which were the 10B(n,α ) 7Li reaction, the H(n ,n )p reaction, and the (n ,α) reactions from the working gas of the GIC. Two effects were considered in the prediction of the experimental spectrum, which were the energy loss of the products in the sample and the wall effect of the sample position well. The predicted spectra play an important role in the guidance of the implementation of the experiment and the processing of the experimental data.

  20. BİR MEŞŞÂÎ FİLOZOFUN GAZZÂLÎ ALGISI: İBN RÜŞD’ÜN GÖZÜYLE GAZZÂLÎ

    Directory of Open Access Journals (Sweden)

    Atilla ARKAN

    2013-06-01

    Full Text Available Bu çalışmada bir Meşşaî filozof olan İbn Rüşd'ün Gazzalî algısını göstermeyi hedeflemekteyiz.Böylece farklı bir bakış açısından Gazzalî´nin daha iyi anlaşılmasını, sentezinin geliştirilebilecek ve eleştirilebilecek yönlerinin açığa çıkmasını amaçlıyoruz. Aynı zamanda bu çalışmanın İbn Rüşd'ün Gazzalî algısı üzerinden kelam-felsefe ilişkilerinin mahiyetine dair bir ışık tutmasını da ümit etmekteyiz. Bu çalışmada iki düşünür arasındaki uzun polemiklere dalmaktan ziyade, İbn Rüşd'ün Gazzalî'yi nasıl algıladığını, kimlik ve karakterinin ayırt edici özelliklerini nasıl tespit ettiğini göstermeye çalışacağız. İlk olarak Kurtubalı filozof,Gazzalî'nin entellektüel kapasite ve yetkinliğinin farkındadır ve bunu teslim eder. İkinci olarak İbn Rüşd'ün gözünde Gazzalî'nin ayırt edici özelliği onun Eşâ€Ÿarî kelamcısı olmasıdır. İbn Rüşd'ün Gazzalî algısının üçüncü unsuru ise onun yöntemine dayanmaktadır. Ona göre, Gazzalî araştırmalarında hakikate ulaşmayı hedeflememişve burhani akıl yürütme yöntemini kullanmamıştır. Son olarak ise İbn Rüşd'ün algısının diğer bir unsurunu da Gazzalî'nin tutarsızlıkları ve aynı konu hakkındaki sık konum değişiklikleri oluşturur. İbn Rüşd'e göre teorik meselelerde icmayı aştıkları sebebiyle Müslüman filozofların küfürle ithamı, ölümden sonraki hayatın keyfiyeti ve mahiyeti ve İlk ilke'den ay altındaki şeylerin aracı varlıklar vasıtasıyla çıkışı gibi bir çok konuda Gazzalî sık sık konum değiştirip tutarsızlığa düşmüştür.

  1. Synthesis, structural characterization and evaluation of floating B-N codoped TiO{sub 2}/expanded perlite composites with enhanced visible light photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Wei; Wang, Xuejiang, E-mail: wangxj@tongji.edu.cn; Zhang, Jing; Zhao, Jianfu; Gu, Zaoli; Zhou, Lijie

    2015-09-15

    Graphical abstract: - Highlights: • We added expanded perlite as a floating carrier to immobilize B-N codoped TiO{sub 2}. • The photo-reaction occurred on the surface of water and easily utilized the solar energy and O{sub 2} to make photodegradation efficiently. • The composites combined the adsorptivity of expanded perlite and photoactivity of B-N-TiO{sub 2}. • The floating photocatalysts give a simple way to recycle, which is important to the application of photocatalysis technology. - Abstract: Floating photocatalysts of boron-nitrogen codoped TiO{sub 2} grafted on expanded perlite (B-N-TiO{sub 2}/EP) were prepared by a facile sol–gel method. The catalysts were characterized by N{sub 2} adsorption–desorption (BET), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis–DRS). The results revealed that the physicochemical properties of the photocatalysts, such as BET surface area, porosity and pore size could be controlled by adjusting the calcination temperature and EP dosage. XRD patterns were mainly influenced by calcination temperature and the transformation of anatase to rutile occurred at 650 °C. Uniform TiO{sub 2} loading, higher surface area and absorption in visible light region were obtained for B-N-TiO{sub 2}/EP calcined at 550 °C with 3.0 g EP addition. Moreover, photocatalytic activity for RhB destruction under visible light irradiation was slightly influenced by TiO{sub 2} loading in the range of 1–3 g EP dosage. BNTEP550 showed the highest photocatalytic activity indicating to be a promising photocatalyst employed to remediate contaminated waters using solar irradiation.

  2. Theoretical investigation of the electronic and magnetic properties of TM (TM=Ti, V, and Cr)-doped w-BN compound

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, Gladys Casiano; López, César Ortega [Grupo Avanzado de Materiales y Sistemas Complejos GAMASCO, Universidad de Córdoba, Montería (Colombia); Espitia R, Miguel J., E-mail: mespitiar@udistrital.edu.co [Grupo GEFEM, Universidad Distrital Francisco José de Caldas, Bogotá (Colombia)

    2016-03-15

    The electronic and magnetic properties of w-BN compound doped with Ti, V, and Cr atoms are calculated by means of the pseudopotential method, employed exactly as implemented in computational Quantum ESPRESSO code. For the description of the electron-electron interaction, generalized gradient approximation (GGA) was used. A half-metallic behavior is predicted for the concentrations B{sub 0.9375}Ti{sub 0.0625}N, B{sub 0.9375}V{sub 0.0625}N, and B{sub 0.9375}Cr{sub 0.0625}N, because of the fact that the majority spins are metallic and the minority spins are semiconducting. We found magnetic moments of 1.0, 2.0 and 3.0 µ{sub β} per supercell, respectively. The main contribution to the magnetic moment mainly comes from the transition metals Ti, V, and Cr, with partialmoments of 0.88 µ{sub β}, 1.75 µ{sub β}, and 2.65 µ{sub β}, respectively. These compounds are good candidates for potential applications in spintronic and as spin injectors. - Highlights: • The B{sub 0.9375}Ti{sub 0.0625}N, B{sub 0.9375}V{sub 0.0625}N, and B{sub 0.9375}Cr{sub 0.0625}N compounds has a magnetic properties. • The magnetic moment for compounds are 1.0, 2.0 and 3.0 µ{sub β} per supercell, respectively. • The magnetic moment mainly comes from the transition metals Ti, V, and Cr, with local moments of 0.88 µ{sub β}, 1.75 µ{sub β}, and 2.65 µ{sub β}, respectively. • The compounds have a half-metallic behavior.

  3. Efficient many-body calculations for two-dimensional materials using exact limits for the screened potential: Band gaps of MoS2, h-BN, and phosphorene

    DEFF Research Database (Denmark)

    Rasmussen, Filip Anselm; Schmidt, Per Simmendefeldt; Winther, Kirsten Trøstrup

    2016-01-01

    Calculating the quasiparticle (QP) band structure of two-dimensional (2D) materials within the GW self-energy approximation has proven to be a rather demanding computational task. The main reason is the strong q dependence of the 2D dielectric function around q = 0 that calls for a much denser sa...... gap of the three prototypical 2D semiconductors, MoS2, h-BN, and phosphorene, including the effect of self-consistency at the GW0 level. The method is implemented in the open source code GPAW....

  4. Propuesta de clasificación técnica de los sistemas de explotación de las BN1G de producción (núcleos

    Directory of Open Access Journals (Sweden)

    Nuria Castañeda Clemente

    1999-01-01

    Full Text Available Se propone una clasificación de los sistemas de explotación de las BN1G de producción a partir de las relaciones entre los distintos atributos que caracterizan a los núcleos. Esta clasificación se estructura en tres niveles. El primero discrimina los sistemas de explotación según su número de superficies de talla. En el segundo nivel, la característica jerarquizadora es la relación geométrica entre superficie /plataforma o entre superficies de talla. El tercer y último nivel atiende a la dirección en la que se explotan estas superficies. This work consists in a classification of the production BN1G (cores exploitation systems, based on tlie reiatlonsfíip between ttie different cíiaracteristic core forms features. Tfiere are tfiree levéis of classification.The first one discrimínate between exploitation systems by tlieir number of debitage surfaces. On the second level the hierarchical feature is the geomethcai relationship between the debitage surface and striking platform or between debitage surfaces. Third level is the direction on exploitation of surfaces.

  5. Effects of heat treatment on microstructure and mechanical properties of Ni60/h-BN self-lubricating anti-wear composite coatings on 304 stainless steel by laser cladding

    Science.gov (United States)

    Lu, Xiao-Long; Liu, Xiu-Bo; Yu, Peng-Cheng; Zhai, Yong-Jie; Qiao, Shi-Jie; Wang, Ming-Di; Wang, Yong-Guang; Chen, Yao

    2015-11-01

    Laser clad Ni60/h-BN self-lubricating anti-wear composite coating on 304 stainless steel were heat treated at 600 °C (stress relief annealing) for 1 h and 2 h, respectively. Effects of the phase compositions, microstructure, microhardness, nano-indentation and tribological properties of the composite coatings with and without heat treatment had been investigated systemically. Results indicated that three coatings mainly consist of the matrix γ-(Ni, Fe) solid solution, the CrB ceramic phases and the h-BN lubricating phases. The maximum microhardness of the coatings was first increased from 667.7 HV0.5 to 765.0 HV0.5 after heat treatment for 1 h, and then decreased to 698.3 HV0.5 after heat treatment for 2 h. The hardness of γ-(Ni, Fe) solid solution without heat treatment and after heat treatment 1 h and 2 h were 5.09 GPa, 7.20 GPa and 3.77 GPa, respectively. Compared with the coating without heat treatment, the friction coefficients of the coating after heat treatment were decreased obviously. Effects of the heat treatment time on friction coefficient were negligible, but were significant on wear volume loss. Comparatively speaking, the laser clad self-lubricating anti-wear composite coating after heat treatment for 1 h presented the best anti-wear and friction reduction properties.

  6. Effect of BN 52021, a specific antagonist of platelet activating factor (PAF-acether), on calcium movements and phosphatidic acid production induced by PAF-acether in human platelets

    Energy Technology Data Exchange (ETDEWEB)

    Simon, M.F.; Chap, H.; Braquet, P.; Douste-Blazy, L.

    1987-02-15

    /sup 32/P-labelled human platelets loaded with quin 2 and pretreated with aspirin were stimulated with 1-100 nM platelet activating factor (PAF-acether or 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in a medium containing the ADP-scavenging system creatine phosphate/creatine phosphokinase. Under these conditions, PAF-acether evoked a characteristic fluorescence change allowing to quantify elevations in cytoplasmic free Ca/sup 2 +/ from internal stores (Ca/sup 2 +/ mobilization) or from external medium (Ca/sup 2 +/ influx), as well as an increased production of phosphatidic acid, reflecting phospholipase C activation. These effects, which can be attributed to PAF-acether only and not to released products such as ADP or thromboxane A2, were strongly inhibited in a dose-dependent manner by BN 52021, a specific antagonist of PAF-acether isolated from Ginkgo biloba. As the drug remained inactive against the same effects elicited by thrombin, it is concluded that BN 52021 does not interfere directly with the mechanism of transmembrane signalling involving inositol-phospholipids or (and) some putative receptor-operated channels, but rather acts on the binding of PAF-acether to its presumed membrane receptor.

  7. Studium stability monoklonální protilátky nimotuzumab modifikované chelátorem DTPA radioaktivně značené luteciem-177 ([177Lu]Lu-hR3(p-SCN-Bn)DTPA)

    OpenAIRE

    Korec, David

    2010-01-01

    Stability studies of monoclonal antibody nimotuzumab modified with chelator DTPA radiolabelled with lutetium-177 ([177Lu]Lu-hR3(p-SCN-Bn)DTPA) Diploma thesis David Korec Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry In this work was target to study the stability of monoclonal antibody Nimotuzumab, which was modified with chelator DTPA radiolabelled with radioactive Lutetium-177 ([177Lu] Lu-hR3 (p- SCN-Bn) DTPA). The radioch...

  8. Seyahatnamelerde Hadîs Kültürü: İbn Battûta Örneği Hadith Culture in Travelogues: The Case of Ibn Battuta

    Directory of Open Access Journals (Sweden)

    Yunus MACİT

    2012-09-01

    Full Text Available Books of Travels are one of the most important sources of Islamichistory and religious life; because they have important functions interms of their transport of the historical, geographical and socio-culturalcharacteristics of a certain time to the present day.Travelling is also an important tradition in Islamic culture;because of travelling is a good way to expand the horizons of knowledgeand experience.As it’s known, Ibn Battuta also known as Shams ad-Din (1304–1368 or 1369, was a Berber Muslim Moroccan explorer, known for hisextensive travels, accounts of which were published in the Rihla. Over aperiod of thirty years, he visited most of the known Islamic world as wellas many non-Muslim lands; his journeys including trips to North Africa,West Africa, Southern Europe and Eastern Europe in the West, and tothe Middle East, South Asia, Central Asia, and China in the East, adistance surpassing threefold his near-contemporary Marco Polo.For this reason Ibn Battuta is considered one of thegreatest travelers of all time.As a devout person Ibn Battuta during his travels tried to learn allof the characteristics of religious and religious organizations whereverhe went and established close contacts with religious people andorganizations, also visited sacred-religious authorities and besides gaveplace to the hadith narrations about this places in his book. In histravelogues, which help as to understand the medieval Islamicgeography his time period, as well as information on socio-cultural andeconomical life of Muslim communities, reflections of Muslim civilizationand sunnah and hadiths of Prophet Muhammad to the religious andgeneral public life and religious persons had narrated. For this reason,İbn Battuta’s works are one of the important sources in terms of hadithand sunnah in studies. Seyahatnameler, İslam tarihi ve dini yaşamı açısından en önemli kaynaklar arasındadır. Bu nedensiz değildir; çünkü seyahatnameler, bir d

  9. İbn Kes̠īr’in İsrā’īliyyāta Yaklaşımı

    Directory of Open Access Journals (Sweden)

    Harun Savut

    2012-03-01

    Full Text Available ÖzetKitap ehline dayanan bilgilerin güvenilirliği ilk asırlardan itibaren İslam âlimlerinin gündemini meşgul etmiştir. İsrā’īliyyāt kavramı etrafında şekillenen tartışmalar günümüzde de devam etmektedir. İsrā’īliyyāt konusunda öne çıkan âlimlerden birisi belki de en önemlisi İbn Kes̠īr’dir (ö.774/1373. O, seleften gelen rivayet ve değerlendirmeleri göz önünde bulundurarak İsrā’īliyyātı belli kriterler çerçevesinde ele almıştır. İbn Kes̠īr İsrā’īliyyātı toptan reddetmemiş, meseleyi İslam’a uyup uymaması açısından değerlendirmiş, tek tek rivayetler üzerinde uyguladığı tahlil ve analizlerle hangi nakillerin alınıp hangilerinin alınamayacağını hükme bağlamıştır. Onun İsrā’īlî haberler karşısındaki tutumunun bilinmesi, günümüzde konu üzerinden yürütülen tartışmaları sağlam bir zemine oturtabilmek açısından önemlidir. Çünkü onun Tefsīru’l-Ḳur’āni’l-‘aẓīm adlı eseri, İsrā’īliyyāt başlığı altında yapılan çalışmalarda müracaat edilen en önemli kaynaklardan birisidir. Onun konuya yaklaşımı anlaşıldığı oranda önceki âlimlerin İsrā’īliyyāt ile neyi kastettikleri, karşı çıktıkları rivayetlerin neler olduğu, bu tür materyalleri nerelerde kullanma ihtiyacı hissettikleri netleşecektir.AbstractThe authenticity of the reports coming from the people of the book occupied the agenda of the Muslim scholars from the first centuries onwards. Controversies regarding the term İsrā’īliyyāt keep continue even today. Ibn Kathir (d.774/1373 is one of the most outstanding scholars on İsrā’īliyyāt, perhaps the most significant one. He dealt with İsrā’īliyyāt within the framework of certain criteria taking the reports and interpretations of his predecessors into account. He didn’t reject İsrā’īliyyāt as a whole, but considered the issue in terms of relevance to Islam, and

  10. European offshore wind power in 2015: record €13bn investment, 3 GW new capacity; La eólica marina europea en 2015: record de inversión 13.000 M€, 3 GW de nueva potencia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-07-01

    Offshore wind investments in Europe doubled in 2015 to €13.3bn in a record year for financing and gridconnected installations. A total of 3,019 MW in new offshore wind capacity came online in European waters in 2015, more than double the capacity connected to the grid in 2014. Europe’s total offshore wind capacity now stands at 11,027 MW. A further 3,034 MW of capacity, spread across ten projects, reached final investment decision last year, a twofold increase on 2014. These are some of the main figures contained in “The European offshore wind industry - key trends and statistics 2015”, a report published by EWEA. (Author)

  11. Verificação do melaço de cana-de-açucar como substrato para produção de bacteriocinas por Lactobacillus plantarum BN /

    OpenAIRE

    Mazo, Jaciara Zarpellon

    1999-01-01

    Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Foi verificada a presença de bacteriocinas em melaço de cana-de-açúcar diluído a 3% e enriquecido, produzidas por Lactobacillus plantarum BN (microrganismo teste) em fermentador, com volume de trabalho de 3,0 litros, sob agitação contínua a 100 rpm, temperatura 30 ± 0,1oC, aeração de 0,7 vvm e tempo de fermentação de 24 horas, inóculo aproximado de 6,0 Log10 UFC/mL com tomada de amostras em interv...

  12. 75 FR 79990 - Airworthiness Directives; B-N Group Ltd. Model BN-2, BN-2A, BN-2A-2, BN-2A-3, BN-2A-6, BN-2A-8...

    Science.gov (United States)

    2010-12-21

    ... tip assembly profiles (top and bottom surfaces) had changed from being convex profiles to concave profiles. There is concern that this could potentially result in, or be caused by, internal structural... INFORMATION CONTACT: Taylor Martin, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301...

  13. 76 FR 15820 - Airworthiness Directives; B-N Group Ltd. Model BN-2, BN-2A, BN-2A-2, BN-2A-3, BN-2A-6, BN-2A-8...

    Science.gov (United States)

    2011-03-22

    ... aircraft. The outboard three inches of the elevator tip assembly profiles (top and bottom surfaces) had changed from being convex profiles to concave profiles. There is concern that this could potentially... FAA, call 816-329-4148. FOR FURTHER INFORMATION CONTACT: Taylor Martin, Aerospace Engineer, FAA, Small...

  14. Interactive effects of sulfur and chromium on antioxidative defense systems and BnMP1 gene expression in canola (Brassica napus L.) cultivars differing in Cr(VI) tolerance.

    Science.gov (United States)

    Terzi, Hakan; Yıldız, Mustafa

    2015-07-01

    Plants suffer with combined stress of sulfur (S) deficiency and hexavalent chromium [Cr(VI)] in soils. There are a few reports on the interactive effects of S-deficiency and Cr(VI) stress. Therefore, the interactions between S nutrition and Cr(VI) stress were investigated in hydroponically grown canola (Brassica napus L.) cultivars differing in Cr(VI) tolerance. The relatively Cr(VI)-tolerant (NK Petrol) and Cr(VI)-susceptible (Sary) cultivars were grown in S-sufficient nutrient solution and then exposed to variable S concentrations [deficient (0 mM S, -S) and sufficient (1 mM S, +S)]. The seedlings were then exposed to 100 μM Cr(VI) for 3 days. S-deficiency (-S/-Cr) and combined stress (-S/+Cr) caused a significant decrease in growth parameters of Sary than NK Petrol (P < 0.05). In -S/+Cr treatment, Cr accumulation in Sary was significantly higher than NK Petrol. The higher level of Cr in Sary increased lipid peroxidation and decreased chlorophyll content. The activities of antioxidant enzymes and cysteine content were significantly higher in NK Petrol than in Sary under combined stress. The levels of ascorbate (AsA) and glutathione (GSH) were significantly decreased by S deficiency. The expression level of metallothionein gene (BnMP1) in the tolerant NK Petrol was increased by -S/+Cr treatment. However, expression level of BnMP1 gene in the susceptible Sary was enhanced by +S/+Cr treatment. This result suggests metallothionein (MT) may be involved in Cr(VI) tolerance under S-deficient condition. In conclusion, S nutrition influenced Cr accumulation and enhanced tolerance caused by a positive effect on defense systems and gene expression.

  15. HERSCHEL FAR-INFRARED SPECTRAL-MAPPING OF ORION BN/KL OUTFLOWS: SPATIAL DISTRIBUTION OF EXCITED CO, H{sub 2}O, OH, O, AND C{sup +} IN SHOCKED GAS

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, Javier R.; Cernicharo, José; Cuadrado, Sara; Etxaluze, Mireya [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Chavarría, Luis [Centro de Astrobiología, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Neufeld, David A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Vavrek, Roland [Herschel Science Center, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Encrenaz, Pierre [LERMA, UMR 8112 du CNRS, Observatoire de Paris, École Normale Supérieure, F-75014 Paris (France); Melnick, Gary J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 66, Cambridge, MA 02138 (United States); Polehampton, Edward, E-mail: jr.goicoechea@icmm.csic.es [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2015-01-20

    We present ∼2' × 2' spectral-maps of Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) outflows taken with Herschel at ∼12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H{sub 2} shocked regions ''Peak 1'' and ''Peak 2'' from that of the hot core and ambient cloud. We analyze the ∼54-310 μm spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of {sup 12}CO (up to J = 48-47), H{sub 2}O, OH, {sup 13}CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L {sub FIR} ≈ 5 × 10{sup –3} ratio and a plethora of far-IR H{sub 2}O emission lines. The high-J CO and OH lines are a factor of ≈2 brighter toward Peak 1 whereas several excited H{sub 2}O lines are ≲50% brighter toward Peak 2. Most of the CO column density arises from T {sub k} ∼ 200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H{sub 2}O/CO ≲ 10{sup –2} abundance ratio. In addition, the very excited CO (J > 35) and H{sub 2}O lines reveal a hotter gas component (T {sub k} ∼ 2500 K) from faster (v {sub S} > 25 km s{sup –1}) shocks that are able to sputter the frozen-out H{sub 2}O and lead to high H{sub 2}O/CO ≳ 1 abundance ratios. The H{sub 2}O and OH luminosities cannot be reproduced by shock models that assume high (undepleted) abundances of atomic oxygen in the preshock gas and/or neglect the presence of UV radiation in the postshock gas. Although massive outflows are a common feature in other massive star-forming cores, Orion BN/KL seems more peculiar because of its higher molecular luminosities and strong outflows caused by a recent explosive event.

  16. BİR SÛFÎ’NİN HADİS YORUMU –RAF’U’L-YEDEYN HADİSİ-İBN ARABÎ ÖRNEĞİ -SUFI’S HADITH INTERPRETATION:THE HADITH ABOUT RAF‘U’L-YEDEYN AND THE EXAMPLE OF IBN ARABÎ

    Directory of Open Access Journals (Sweden)

    Mehmet AYHAN

    2012-07-01

    Full Text Available Bu makalede İbn Arabî’nin bir hadisi anlama ve yorumlaması ele alınmıştır. İbn Arabî’nin “ raf‘ul-yedeyn/namazda ellerin kaldırılması” hadîsine bakış açısı Fütûhât adlı eseri ekseninde izah edilmiştir. İbn Arabî, bu hadisi yorumlarken fıkıh ve hadisin yanında tasavvuf ilmini ve özel yöntemlerini de işin içine katmaktadır. Onun diğer bilginlerden farklı olarak bir hadisi izah ederken bu üç sacayağını birlikte kullandığı ve bu üç ilmi mezcederek külli bir bakış açısıyla meseleye yaklaştığı görülmektedir. İbn Arabî’nin özel rivâyet metotlarından ve tasavvufî bilgi kaynaklarından olan rüyanın işlevi bir hadis yorumu özelinde nazara verilmektedir. İbn Arabî, hadisi rüya yoluyla alırken aynı zamanda hadis kaynaklardaki yerini ve durumunu belirtmektedir. Bunların yanında ilgili hadisleri kritiğe tabi tutarak çeşitli sonuçlara ulaşmaktadır.-In this article, the understanding and interpretation of a specific Hadith by Ibn Arabi is handled. Ibn Arabi’s view of the Hadith that is related to the problem of holding up the hands during Namaz (raf‘ul-yedeyn has been explained in the light of his work known as Fütûhât. Beside the general knowledge and terminology of Fiqh and Hadith, Ibn Arabi has also included the conceptualizations and special methodologies of Tasavvuf within his interpretation of that specific Hadith. It is concluded that what differentiates Ibn Arabi from other scholars in this area is his attempt to make use of these three areas of knowledge as a trivet so that a synthesis can be achieved when interpreting a Hadith.

  17. BİR SÛFÎ’NİN HADİS YORUMU –RAF’U’L-YEDEYN HADİSİ-İBN ARABÎ ÖRNEĞİ -SUFI’S HADITH INTERPRETATION:THE HADITH ABOUT RAF‘U’L-YEDEYN AND THE EXAMPLE OF IBN ARABÎ

    Directory of Open Access Journals (Sweden)

    Mehmet AYHAN

    2012-01-01

    Full Text Available Bu makalede İbn Arabî’nin bir hadisi anlama ve yorumlaması ele alınmıştır. İbn Arabî’nin “ raf‘ul-yedeyn/namazda ellerin kaldırılması” hadîsine bakış açısı Fütûhât adlı eseri ekseninde izah edilmiştir. İbn Arabî, bu hadisi yorumlarken fıkıh ve hadisin yanında tasavvuf ilmini ve özel yöntemlerini de işin içine katmaktadır. Onun diğer bilginlerden farklı olarak bir hadisi izah ederken bu üç sacayağını birlikte kullandığı ve bu üç ilmi mezcederek külli bir bakış açısıyla meseleye yaklaştığı görülmektedir. İbn Arabî’nin özel rivâyet metotlarından ve tasavvufî bilgi kaynaklarından olan rüyanın işlevi bir hadis yorumu özelinde nazara verilmektedir. İbn Arabî, hadisi rüya yoluyla alırken aynı zamanda hadis kaynaklardaki yerini ve durumunu belirtmektedir. Bunların yanında ilgili hadisleri kritiğe tabi tutarak çeşitli sonuçlara ulaşmaktadır.-In this article, the understanding and interpretation of a specific Hadith by Ibn Arabi is handled. Ibn Arabi’s view of the Hadith that is related to the problem of holding up the hands during Namaz (raf‘ul-yedeyn has been explained in the light of his work known as Fütûhât. Beside the general knowledge and terminology of Fiqh and Hadith, Ibn Arabi has also included the conceptualizations and special methodologies of Tasavvuf within his interpretation of that specific Hadith. It is concluded that what differentiates Ibn Arabi from other scholars in this area is his attempt to make use of these three areas of knowledge as a trivet so that a synthesis can be achieved when interpreting a Hadith.

  18. BN and BN oxide nanosheets based nanosensor for paracetamol adsorption: a first principles simulation

    Directory of Open Access Journals (Sweden)

    Miguel Castro

    2014-04-01

    Full Text Available The effects that the adsorption of the paracetamol molecule produce on the structural and electronic properties of boron nitride (hBNNs; B27N27H18 and boron nitride oxide (hBNONs; B27N27H17 + O + (OH3 + COOH hexagonal symmetry nanosheets were studied by means of Density Functional Theory. The generalized gradient approximation proposed by Heyd—Scuseria—Ernzerhof ((HSEh1PBE―GGA was used in concert with 6-31G(d basis sets. Several candidate structures, 9 and 13 for the hBNNs―Paracetamol and BNONs―Paracetamol interactions, respectively, were used for the geometry optimization procedure. The results show that in the lowest energy absorption site the paracetamol molecule reaches a parallel orientation to the surface of the nanosheets, producing physisorption for hBNNs―Paracetamol and chemisorption for BNONs―Paracetamol. Besides, the adsorption process yields an increase of the polarity opening the possibility for the solubility and dispersion of these compounds. The paracetamol molecule promotes also a decrease of the reactivity parameter, which is crucial for biological applications of these systems. Referred to pristine hBNNs and BNONs, the work functions of hBNNs-Paracetamol and BNONs―Paracetamol are diminished. That is, these functionalized 2D systems yields appropriate conditions for field emission and they may be used as sensors of such pharmaceutical compound.

  19. Study of the reduction in detection limits of track detectors used for {sup 10}B(n,α){sup 7}Li reaction rate measure through annealing and chemical etching experiments; Estudo da reducao nos limites de deteccao de detectores de tracos utilizados na medida de taxa de reacao {sup 10}B(n, α){sup 7}Li atraves de experimentos de annealing e ataque quimico

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Herminiane L.; Smilgys, Barbara; Guedes, Sandro, E-mail: hluizav@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Castro, Vinicius A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-08-15

    The Boron Neutron Capture Therapy (BNCT) is an experimental radiotherapy for cancer treatment. It is based on {sup 10}B(n, α){sup 7}Li reaction, which can be measured by track detectors capable of recording events that strike them. With this recording, it is possible to determine the number of alpha particles and recoiling Lithium-7 nucleus, reaction products, and from this information, which amount of radiation dose a patient is exposed to. In this work, PADC detectors were characterized, irradiated at the IEA-R1 IPEN/CNEN reactor to assess the contribution of the{sup 10}B(n, α){sup 7}Li reaction and protons from fast neutron scattering with the elements that compounds the tissue. With the aim of reducing the proton background, the detectors were subjected to heating experiments at 80°C for periods in the range 0-100 hours. This was done in order to restore partially modified structure of the detector, causing a reduction in the size and density of tracks. This effect is known as annealing. For the visualization of tracks at microscope, detectors were made three chemical attacks with sodium hydroxide (NaOH) for 30, 60 and 90 minutes at 70°C. It was observed a reduction in the track density achieving a plateau heating time of 50 hours. For detectors that have not undergone annealing and were etched with another etchant, PEW solution, a reduction of 87% in track density was obtained. (author)

  20. Vendantic view on life and consciousness: BN Shanta is correct.

    Science.gov (United States)

    Jagannadham, Medicharla Venkata

    2016-01-01

    The explanation for Vedanta offered by Bhakti Niskama Santa (BNS)1 is valid from both scientific and philosophical grounds. It seems that the published critique of Gustavo Caetano-Anollés (GCA)2 to Shanta's paper is purely emotional and does not have any valid scientific or philosophical justification. In his rebuttal to Caetano-Anollés's critique, Shanta3 highlighted how the concept of 'Organic Whole' in Vedanta is completely different than that of Creationist Movement and Intelligent Design. Thus Caetano-Anollé's attempt to equate Vedanta with Creationist Movement and Intelligent Design is merely superfluous. This article highlights the validity of the argument made by Bhakti Niskama Shanta1 and thus also intends to clarify why the Caetano-Anollés critique is groundless.

  1. Operation Resettlement, Fort Chafee, Arkansas. 1st Psyop Bn

    Science.gov (United States)

    1981-01-01

    fundener.tales que r.an .T, Primero. - l^a limpieza de las area it: vivienda y ti >ampai req cnsatilidad, nc tires papelec c basuras t...el terrcn envases de Iqahe, bandejas de carton, quc I’d. Vea e>: t I de basura o en las bolsas pl&sticas para qu< Mantenga su nuevc hogar...Primero. - La limpieza de las area de vivienda y el aempanento en general, ya que es su respansabilidad, no tires papeles o basuras en el terreno del

  2. Space traveller to see stars born 13bn years ago

    CERN Multimedia

    Radford, T

    2004-01-01

    British scientists are working on the James Webb telescope, successor to tje Hubble space telescope. A supersensitive camera called Miri - mid infrared instrument - being built by an international team, will be a key part of the European and American instrument (1 page)

  3. Inelastic scattering at the B K edge of hexagonal BN

    Energy Technology Data Exchange (ETDEWEB)

    Jia, J.J.; Callcott, T.A.; Zhou, L. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

    1997-04-01

    Many recent soft x-ray fluorescence (SXF) studies have shown that inelastic scattering processes make important contributions to the observed spectra for excitation near the x-ray threshold. These effects are all attributed to a process, usually called an electronic Raman scattering (ERS) process, in which energy is lost to an electronic excitation. The theory has been described using second order perturbation theory by Tulkki and Aberg. In different materials, the detailed nature of the electronic excitation producing the energy loss may be very different. In crystalline Si, diamond and graphite, changes in spectral shape and dispersion of spectral features with variation of the excitation energy are observed, which are attributed to k conservation between the photoelectron generated in the excitation process and the valence hole remaining after the coupled emission process. Hence the process is strongly localized in k-space. In haxagonal boron nitride, which has a lattice and band structure very similar to graphite, inelastic scattering produces very different effects on the observed spectra. Here, the inelastic losses are coupled to a strong resonant elastic scattering process, in which the intermediate state is a localized core exciton and the final state is a localized valence exciton, so that the electronic excitation is strongly localized in real rather than reciprocal space.

  4. Indian Contributions S. Seetha , BN Ashoka & TMK Marar

    Indian Academy of Sciences (India)

    this peak had an amplitude of 0.1 mma (Kurtz et al. 2002). It may be noted that this amplitude was well above the noise levels in the previous runs of 1986 and why it was not detected is still an open question. The amplitudes of various modes do change with time and this could be the reason for the non-detection of the new ...

  5. High thermoelectricpower factor in graphene/hBN devices

    National Research Council Canada - National Science Library

    Duan, Junxi; Wang, Xiaoming; Lai, Xinyuan; Li, Guohong; Watanabe, Kenji; Taniguchi, Takashi; Zebarjadi, Mona; Andrei, Eva Y

    2016-01-01

    .... Although passive cooling in graphene-based devices is quite effective due to graphene's extraordinary heat conduction, active cooling has not been considered feasible due to graphene's low thermoelectric power factor...

  6. Radiation induced luminescence processes in c-BN

    DEFF Research Database (Denmark)

    Trinkler, L.; Berzina, B.; Benabdesselam, M.

    2004-01-01

    Spectral properties of cubic boron nitride have been studied using methods of photoluminescence (PL), X-ray excited luminescence (XL), thermoluminescence (TL) and optically stimulated luminescence. It is found that emission of cubic boron nitride is presented by 4 subbands, their relative yield...... is determined by the excitation type: blue, green (dominant) and red bands are observed in PL, ultraviolet, blue (dominant), green and red bands-in XL. Three thermal peaks are found in TL curves in the 0-700degreesC temperature range, their presence and intensity depend on radiation type used. A tentative...

  7. İBN EL-ESİR HAZARLAR HAKKINDA

    OpenAIRE

    Kemaloğlu, Muhammet

    2014-01-01

    Doğuda Hazar Denizinden batıda Tuna nehrine kadar uzanan, Altay bozkırlarının bir nevi devamıniteliğindeki Karadeniz’in kuzeyindeki bozkırlar (Güney Rusya Bozkırları) tarih öncesi ve tarihi devirlerde birçok kültüre ve kavme ev sahipliği yapmıştır. Bu bozkırın Orta Çağdaki ev sahipleri ise hiç şüphesiz tarihin her devrinde kendini gösteren ve büyük siyasi teşekküller kuran Türklerdir. İşte bu Türklerin adı Hazarlardır. Azerbaycan Türklüğü ve Azerbaycan Türkçesinin şekillenmesinde Hazarların ç...

  8. Descenso de los niveles de propéptido natriurético de tipo B-N terminal luego de la reversión de pacientes con fibrilación auricular y función ventricular conservada

    Directory of Open Access Journals (Sweden)

    Claudio Higa

    2011-04-01

    Full Text Available El objetivo fue comparar los niveles de Pro Péptido Natriurético tipo B-N terminal (Pro-BNP-NT basales y post reversión en pacientes con fibrilación auricular solitaria (FAS de comienzo reciente y con función ventricular izquierda conservada. Se determinaron niveles del Pro BNP NT antes y después de su reversión en treinta pacientes con FAS de comienzo reciente y fracción de eyección de ventrículo izquierdo ≥ 50%. Basalmente, los niveles de Pro BNP NT fueron significativamente más elevados respecto a un grupo control sano: 529 pg/ml (157-1763 versus 31.5 pg/ml (24-76, p < 0.0001. Las concentraciones de Pro BNP NT descendieron significativamente luego de la cardioversión de 529 (157-1763 a 318 (98-870 pg/ml, p < 0.001. Los descensos se objetivaron tanto luego de la cardioversión eléctrica como de la obtenida por vía farmacológica, 345 (153-1151 pg/ml a 169 (86-407 pg/ml, p: 0.02 y de 1624 (541-4010 pg/ml a 856 (532-1160 pg/ml, p < 0.001, respectivamente. Este fenómeno se observó fundamentalmente en aquellos con una FAS con duración mayor a 8 horas: 1289 (338-2103 a 410 (169-905 pg/ml, p < 0.001. No se observó correlación entre los cambios de la frecuencia cardíaca y del Pro BNP NT pre y post cardioversión a ritmo sinusal. Se observaron descensos significativos de Pro BNP NT basalmente y post reversión (tanto farmacológica como eléctrica en pacientes con FA de reciente aparición y función ventricular conservada. Estos descensos fueron más ostensibles a partir de las 8 horas de duración de la arritmia.

  9. Suppression of 1/f noise in near-ballistic h-BN-graphene-h-BN heterostructure field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Stolyarov, Maxim A.; Liu, Guanxiong; Balandin, Alexander A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL) and Phonon Optimized Engineered Materials (POEM) Center, Department of Electrical and Computer Engineering, Bourns College of Engineering, University of California – Riverside, Riverside, California 92521 (United States); Rumyantsev, Sergey L. [Departments of Electrical, Computer and Systems Engineering and Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Shur, Michael [Departments of Electrical, Computer and Systems Engineering and Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-07-13

    We have investigated low-frequency 1/f noise in the boron nitride–graphene–boron nitride heterostructure field-effect transistors on Si/SiO{sub 2} substrates (f is a frequency). The device channel was implemented with a single layer graphene encased between two layers of hexagonal boron nitride. The transistors had the charge carrier mobility in the range from ∼30 000 to ∼36 000 cm{sup 2}/Vs at room temperature. It was established that the noise spectral density normalized to the channel area in such devices can be suppressed to ∼5 × 10{sup −9 }μm{sup 2 }Hz{sup −1}, which is a factor of ×5 – ×10 lower than that in non-encapsulated graphene devices on Si/SiO{sub 2}. The physical mechanism of noise suppression was attributed to screening of the charge carriers in the channel from traps in SiO{sub 2} gate dielectric and surface defects. The obtained results are important for the electronic and optoelectronic applications of graphene.

  10. Temperature- and density-dependent transport regimes in a h-BN/bilayer graphene/h-BN heterostructure

    Science.gov (United States)

    Cobaleda, C.; Pezzini, S.; Diez, E.; Bellani, V.

    2014-03-01

    We report on multiterminal electrical transport measurements performed on a bilayer graphene sheet enclosed by two hexagonal boron nitride flakes. We characterize the temperature dependence of electrical resistivity from 300 mK to 50 K, varying the carrier densities with a back gate. The resistivity curves clearly show a temperature-independent crossing point at density n =nc≈2.5×1011 cm-2 for both positive and negative carriers, separating two distinct regions with dρ /dT0, respectively. Our analysis rules out the possibility of a zero-T quantum phase transition, revealing instead the onset of robust ballistic transport for n >nc, while the T dependence close to the neutrality point is the one expected from the parabolic energy-momentum relation. At low temperature (T ≪10 K), the data are compatible with transport via variable range hopping mediated by localized impurity sites, with a characteristic exponent 1/3 that is renormalized to 1/2 by Coulomb interaction in the high-density regime.

  11. Effects of hydrogen adsorption on the properties of double wall BN and (BN){sub x}C{sub y} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, A. [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58059-900 João Pessoa, PB (Brazil); Azevedo, S., E-mail: sazevedo@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58059-900 João Pessoa, PB (Brazil); Kaschny, J.R. [Instituto Federal da Bahia – Campus Vitoria da Conquista, Avenida Amazonas 3150, 45030-220 Vitória da Conquista, BA (Brazil)

    2016-01-15

    In the present contribution, we apply first-principles calculations, based on the density functional theory, to study the effects of hydrogen adsorption on the structural and electronic properties of boron nitride and hybrid carbon–boron nitride double wall nanotubes. The results demonstrate that the hydrogen decoration induces significant structural deformation and an appreciable reduction in the gap energy. When the number of hydrogen atoms introduced on the outer wall is increased, desorption of hydrogen pairs are observed. The calculations indicate that each adsorbed hydrogen atom induces a structural deformation with an energetic cost of about 68 meV/atom. It is also found that the introduction of hydrogen atoms can be applied as an efficient tool for tuning the electronic properties of such structures. - Graphical abstract: Localized density of states of a hydrogenated double wall boron nitride nanotube. Some hydrogen pairs are desorbed, forming H{sub 2} molecules. - Highlights: • Hydrogenation induces structural deformation and reduction in the gap energy. • Each H atom induces a deformation with an energetic cost of about 68 meV/atom. • In some cases, desorption of H pairs from the outer wall is observed.

  12. Tool life of the edges coated with the c-BN+h-BN coatings with different structures during hard machinable steel machining

    Directory of Open Access Journals (Sweden)

    Kupczyk, M.

    2005-12-01

    Full Text Available In the presented paper the experimental results concerning the functional quality (durability during steel machining of thin, superhard coatings produced on the cutting edges are described. Differences among mentioned properties of coatings mainly result from a coating structure. But the structure of coatings results from deposition parameters Superhard boron nitride coatings were deposited on insert cutting edges made of cemented carbides by the pulse-plasma method applying different values of the discharge voltage. The comparative investigations of mentioned coatings have been concerned of tool life of edges during hard machinable material machining (nitriding steel hardened in oil. In these investigations for the purpose of additional increase of coatings adhesion to substrates an interfacial layers were applied.

    En este trabajo se describen los resultados experimentales referentes a la calidad funcional (durabilidad durante el mecanizado del acero de recubrimientos delgados, de elevada dureza del filo de corte. Las diferencias en las propiedades de los recubrimientos se deben, principalmente, a la estructura del recubrimiento. No obstante, la estructura del recubrimiento está relacionada con los parámetros de la deposición. Recubrimientos de nitruro de boro de elevada dureza se depositaron sobre filos de corte insertados, fabricados con carburos cementados mediante el método de pulsos de plasma aplicando diferentes valores de voltaje de descarga. Las investigaciones comparativas de los mencionados recubrimientos han relacionado la vida del filo de la herramienta durante el mecanizado del material (acero nitrurado endurecido en aceite. En estas investigaciones se aplicaron capas interfaciales para aumentar la adherencia del recubrimiento.

  13. Cyber Security Risk Evaluation of a Nuclear I&C Using BN and ET

    OpenAIRE

    Jinsoo Shin; Hanseong Son; Gyunyoung Heo

    2017-01-01

    Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluatio...

  14. An upper limit to the acetylene abundance toward BN in the orion molecular cloud

    Science.gov (United States)

    Knacke, R. F.; Kim, Y. H.; Irvine, W. M.

    1989-01-01

    A search for the acetylene (C2H2) nu3 infrared vibration-rotation absorption near 3 microns toward the Becklin-Neugebauer source in the Orion molecular cloud is reported. The relative abundance of C2H2/CO in the quiescent gas is less than 0.003.

  15. Decolourization and degradation of azo Dye, Synozol Red HF6BN ...

    African Journals Online (AJOL)

    The observation of no zones of inhibition on agar plates and growth of Vigna radiata in the presence of dye extracted sample indicated that the fungal degraded dye metabolites are nontoxic to beneficial micro-flora and plant growth. Therefore, P. ostreatus has promising potential in colour removal from textile wastewater ...

  16. Plutarco en España: edición del mnanuscrito Madrid BN 6365

    OpenAIRE

    Morales Ortiz, Alicia

    1999-01-01

    El presente trabajo consiste en la edición de la traducción castellana del tratado de Plutarco De capienda ex inimicis utilitate, datada en el siglo XVI y realizada por el "maestro Gaspar Hernández", que se conserva manuscrita en la Biblioteca Nacional de Madrid (Ms. 6365). Se ha añadido una breve introducción que sitúa esta versión en el contexto de la recepción de Plutarco en el Humanismo español y en la problemática de la traducción de los textos clásicos griegos en nuestro Renacimiento...

  17. Changing the Organization for Cataloguing in the BnF: a Long-term Project

    Directory of Open Access Journals (Sweden)

    Philippe Raccah

    2002-07-01

    Full Text Available An inter-departmental committee of the French National Library has been working since the beginning of the year to review the overall cataloguing processes and the specific roles of the different sections within the library. It is recognized that there are mainly two different cataloguing processes within the library, which are distinct but equally important: legal deposit materials are to be catalogued with the best possible quality and as exhaustively as possible while other materials are acquired selectively and have to meet user needs within the library first. The catalogue of the library has to be as consistent as possible taking into consideration the staff and budget resources of the library.

  18. A first principle investigation into effect of B and BN doped C60 in ...

    Indian Academy of Sciences (India)

    22

    Hydrogen storage in the solid state has advantages of safety and higher gravimetric density. [5]. Among various solid state storage options, the complex metal hydrides of lighter elements (Li, B, Na, Mg and Al) have high volumetric and gravimetric densities [6]. The usage of complex metal hydrides has been hindered due to ...

  19. and BN-doped C60 in lowering dehydrogenation of MXH4

    Indian Academy of Sciences (India)

    2017-11-23

    Nov 23, 2017 ... Among various scientific and technological challenges, search for hydrogen storage material that satisfies the commercial targets of gravimet- ric density and safety remains central for hydrogen economy. [3,4]. Hydrogen storage in the solid state has advantages of safety and higher gravimetric density [5].

  20. Growth kinetics of white graphene (h-BN) on a planarised Ni foil surface

    National Research Council Canada - National Science Library

    Cho, Hyunjin; Park, Sungchan; Won, Dong-Il; Kang, Sang Ook; Pyo, Seong-Soo; Kim, Dong-Ik; Kim, Soo Min; Kim, Hwan Chul; Kim, Myung Jong

    2015-01-01

    .... The surface of the nickel (Ni) foil was first polished by electrochemical polishing (ECP) and subsequently annealed in hydrogen at atmospheric pressure to suppress the effect of the surface morphology...

  1. Amplification of the active site of BnLIP3 gene of Brassica napus L ...

    African Journals Online (AJOL)

    Utilisateur

    ... of a Lipase Gene from. Rice (Oryza sativa cv. Dongjin). Mol. Cells. 18:40-45. Zhiqiang L, Xiaoyu L, Zhenming C, Lin W, Jing L, Xianghong W (2008). Cloning, characterization and expression of the extracellular lipase gene from Aureobasidium pullulans HN2-3 isolated from sea saltern. Antonie.van. Leeuwenhoek.

  2. Dicty_cDB: FC-BN17 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Acid sequence ---NNNNNNNNNNEFSKRSYGHNQNQIPHHQHKGERKHPTIGQNRNSNNNTQSQQRNKFS DRFAHQRQSSYDYDNPFEFKEFNNHLNN...k Frame C: ---NNNNNNNNNNEFSKRSYGHNQNQIPHHQHKGERKHPTIGQNRNSNNNTQSQQRNKFS DRFAHQRQSSYDYDNPFEFKEFNNHLNN

  3. Negative Refraction with High Transmission in Graphene-hBN Hyper Crystal

    CERN Document Server

    Sayem, Ayed Al; Jahangir, Ifat; Rahman, Md Saifur

    2015-01-01

    In this article, we have theoretically investigated the performance of graphene-hexagonal Boron Nitride hyper crystals to demonstrate all angle negative refraction.Hexagonal Boron Nitride, the latest natural hyperbolic material; can be a very strong contender to form a hyper crystal with graphene due to its excellence as a graphene-compatible substrate. Although bare hexagonal Boron Nitride can exhibit negative refraction, the transmission is generally low due to its high reflective nature. On the other hand, due to two dimensional nature and metallic characteristics of graphene in the frequency range where hexagonal Boron Nitride behaves as a type-I hyperbolic Metamaterial, we have found that graphene-hexagonal Boron Nitride hyper-crystals exhibit all angle negative refraction with superior transmission. This has been possible because of the strong suppression of reflection from the hyper-crystal without any adverse effect on the negative refraction properties. This finding can prove very useful in applicati...

  4. Phonon thermal properties of graphene on h-BN from molecular dynamics simulations

    Science.gov (United States)

    Zou, Ji-Hang; Cao, Bing-Yang

    2017-03-01

    Phonon thermal properties of graphene on hexagonal boron nitride are investigated by the molecular dynamics simulations combined with lattice dynamics theory. It is found that the dispersion curves have minor changes for supported graphene because the interlayer coupling is too weak to shift the harmonic phonon properties. The ZA and ZO phonon lifetimes are significantly reduced in supported graphene due to the breakdown of the symmetry-based selection rule. The dominant mean free path (MFP) of graphene is reduced from 90-800 nm to 60-500 nm at 300 K. The mode thermal conductivities of free and supported graphene are 3517 W/ (m.K) and 2200 W/ (m.K) at 300 K, respectively. The thermal conductivity of supported graphene decreases by about 37.4% due to the large reduction of flexural phonon lifetimes, and the relative contribution of flexural modes decreases from 35.0% to 16.7%.

  5. BN~r" .wU1!9 1\\ I

    Indian Academy of Sciences (India)

    email, postal and residential address, telephone numbers, academic qualifications starting from B.Sc 'onwards, teaching experience, courses taught, positions held and a statement indicating reasons for interest in participating in the course. Teachers applying for participation are also requested to indicate that necessary ...

  6. Electron-Phonon Renormalization of Electronic Band Structures of C Allotropes and BN Polymorphs

    Science.gov (United States)

    Tutchton, Roxanne M.; Marchbanks, Christopher; Wu, Zhigang

    The effect of lattice vibration on electronic band structures has been mostly neglected in first-principles calculations because the electron-phonon (e-ph) renormalization of quasi-particle energies is often small (Career Award (Grant No. DE-SC0006433). Computations were carried out at the Golden Energy Computing Organization at CSM and the National Energy Research Scientific Computing Center (NERSC).

  7. A FAST BREEDER REACTOR SPENT FUEL MEASUREMENTS PROGRAM FOR BN-350 REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    P. STAPLES; J. HALBIG; ET AL

    1999-04-01

    A project to verify the fissile content of fast breeder reactor spent nuclear fuel is underway in the Republic of Kasakhstan. There are a variety of assembly types with different irradiation histories and profiles in the reactor that require a variety of measurement and analysis procedures. These procedures will be discussed and compared as will the general process that has been designed to resolve any potential measurement discrepancies. The underwater counter is part of a system that is designed to assist the International Atomic Energy Agency (IAEA) in maintaining continuity of knowledge from the time of measurement until the measured item is placed in a welded container with a unique identification. In addition to satisfying IAEA requirements for the spent nuclear fuel, this measurement program is able to satisfy some of the measurement requirements for the Kasakhstan Atomic Energy Agency concerning the repackaging of the spent nuclear fuel into a standard canister. The project is currently operational in a mode requiring the IAEA's continuous presence.

  8. Device Performance and Reliability Improvements of AlGaBN/GaN/Si MOSFET

    Science.gov (United States)

    2016-02-04

    Metal insulator semiconductor AlGaN /GaN high electron mobility transistors (MISHEMTs) are promising for power device applications due to a lower leakage...stoichiometry of the ALD Al2O3 and the PEALD is the same within detectable limits. as seen in Fig. 1.5. The detection of a small fluorine (F) peak is noted and...stability, extends the application of the III-nitride to high temperature and high power. Moreover, because of the close lattice constants and thermal

  9. 78 FR 64894 - Airworthiness Directives; B-N Group Ltd. Airplanes

    Science.gov (United States)

    2013-10-30

    ... cable sliding end assembly and installation of the incorrect end fitting on engine control cable... of two occurrences where a failure of engine control cable assemblies has caused engine control difficulties. In both reported cases, the cable sliding end assemblies were in poor condition and in both cases...

  10. Effect of an electric field on the properties of BN Möbius stripes

    Energy Technology Data Exchange (ETDEWEB)

    Lemos de Melo, J. [Departamento de Física, CCEN, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900 João Pessoa, PB (Brazil); Azevedo, S., E-mail: sazevedo@fisica.ufpb.br [Departamento de Física, CCEN, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900 João Pessoa, PB (Brazil); Kaschny, J.R. [Instituto Federal da Bahia, Campus Vitória da Conquista, Av. Amazonas 3150, 45075-265 Vitória da conquista, BA (Brazil)

    2014-09-15

    In the present work, we present a first-principles study on the effects of an external electric field on the structural stability and electronic properties of boron nitride Möbius stripes with armchair and zigzag chirality. The calculation results indicate that the gap energy can be remarkably reduced by the application of an external field. Such reduction is in principle attributed to the occurrence of Stark effect, which significance depends on the orientation of the applied field relative to the stripe axis. Moreover, the electric field produces significant changes on dipole momentum of the structure and induces a negative shift on the calculated total energy, reducing the obtained formation energy. - Highlights: • The gap energy is remarkably reduced by the application of an external field. • The electric field produces significant changes on dipole momentum. • The field induces a negative shift on the total energy due to Stark effect.

  11. Limitations of effective medium theory in multilayer graphite/hBN heterostructures

    DEFF Research Database (Denmark)

    Petersen, René; Pedersen, Thomas Garm; Gjerding, Morten Niklas

    2016-01-01

    We apply effective medium theory (EMT) to metamaterials consisting of a varying number of consecutive sheets of graphene and hexagonal boron nitride, and compare this with a full calculation of the permittivity and the reflection based on the tight binding method and the transfer matrix method...

  12. Theoretical characterization of the BN and BP coronenes by IR, Raman, and UV-VIS spectra.

    Science.gov (United States)

    de Abreu, Leandro; López-Castillo, Alejandro

    2012-07-28

    Boron-nitrogen coronene (BNC) and boron-phosphorous coronene (BPC), not yet synthesized molecules and of possible interest for material science, are composed of six condensed rings of borazine and boraphosphabenzene molecules, respectively. They are similar to the carbon coronene molecule (CC). Moreover, CC and BNC are isoelectronic and the BPC is formally isoelectronic with respect to other coronenes, if only the valence electrons are considered. In this work, the BNC and BPC were theoretically characterized using IR, Raman, and UV-VIS spectroscopies. The coronenes studied have D(6h) and D(3h) symmetries for carbon and boron compounds, respectively. The calculated vibrational and electronic spectra for the CC are in good agreement with the experimental data, indicating that the calculations for BNC and BPC will be useful to identify these compounds, when synthesized. The main vibrational modes of the CC, BNC, and BPC are correlated. However, the BPC vibrational frequencies are substantially lower than the CC and BNC ones. The electronic ground state studies showed that the BPC has intermediate characteristics between the CC and BNC.

  13. Data of evolutionary structure change: 1BN1A-1RJ5B [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 7309999465942383 46.16299819946289 > -0.11699999868869781 0.7900000214576721...07500000298023224 0.09600000083446503 > 0.7818689942359924 1.1783250570297241...58100128173828 47.77899932861328 > -0.05700000002980232 0.8180000185966492...15399999916553497 -0.12300000339746475 > 0.9818189740180969 1.652670979499817...298999786376953 61.77799987792969 > 0.03200000151991844 0.8809999823570251

  14. Data of evolutionary structure change: 1BN4A-1RJ5B [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 8040000200271606 46.13399887084961 > -0.11800000071525574 0.7919999957084656...07699999958276749 0.09300000220537186 > 0.7773039937019348 1.1760270595550537...57899856567383 47.80699920654297 > -0.06199999898672104 0.8190000057220459...1589999943971634 -0.12200000137090683 > 0.990979015827179 1.6870429515838623...319000244140625 61.77899932861328 > 0.02800000086426735 0.8799999952316284

  15. Dicty_cDB: FC-BN02 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available chromosome II reading frame ORF YBR048w. 58 1e-13 3 Z35918 |Z35918.1 S.cerevisiae chromosome II reading frame...3 Z74321 |Z74321.1 S.cerevisiae chromosome IV reading frame ORF YDR025w. 52 3e-09 3 L15408 |L15408.1

  16. County rises to hi-tech challenge: Agency vies for pounds 1bn European science project

    CERN Multimedia

    Meek, J

    2002-01-01

    The Yorkshire Forward development agency in northern England is backing the White Rose Consortium to build the European Spallation Source (ESS). One of the rivals for the investment is the Rutherford Appleton Laboratory in Oxfordshire (1 page).

  17. Dicty_cDB: FC-BN06 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ci qrikrsrtynfkdtiw*IFNFKLLKYGTEEQ--- ---LLTKSMVNSCGNST*iskkivtkrknvewispn*snfvqitlktysqvngvqrf*ik l*rmpmeik...l*lnn*lknlkety*mslsnmthhv*skpy*smamkhkerly skn*kiknlqfqrhnmvdf*f*tlkiry*rtk--- ---LLTKSMVNSCGNST*iskkivtkrknvewisp

  18. Structural, electronic and magnetic properties of chevron-type graphene, BN and BC2N nanoribbons

    Science.gov (United States)

    Guerra, T.; Azevedo, S.; Kaschny, J. R.

    2017-04-01

    Graphene nanoribbons are predicted to be essential components in future nanoelectronics. The size, edge type, arrangement of atoms and width of nanoribbons drastically change their properties. Boronnitrogencarbon nanoribbons properties are not fully understood so far. In the present contribution it was investigated the structural, electronic and magnetic properties of chevron-type carbon, boron nitride and BC2N nanoribbons, using first-principles calculations. The results indicate that the structural stability is closely related to the discrepancies in the bond lengths, which can induce structural deformations and stress. Such nanoribbons present a wide range of electronic behaviors, depending on their composition and particularities of the atomic arrangement. A net magnetic moment is found for structures that present carbon atoms at the nanoribbon borders. Nevertheless, the calculated magnetic moment depends on the peculiarities of the symmetric arrangement of atoms and imbalance of carbon atoms between different sublattices. It was found that all structures which have a significant energy gap do not present magnetic moment, and vice-versa. Such result indicates the strong correlation between the electronic and magnetic properties of the chevron-type nanoribbons.

  19. Spark Plasma Sintered AlN-BN Composites and Its Thermal Conductivity

    NARCIS (Netherlands)

    Zhao Haiyang, [No Value; Wang Weimin, [No Value; Wang Hao, [No Value; Fu Zhengyi, [No Value

    2008-01-01

    A series of samples of hexagonal boron nitride-aluminum nitride ceramic composites with different amounts of CaF(2) as sintering aid were prepared by spark plasma sintered at 1700-1850 degrees C for 5 min. The addition of CaF(2) effectively lowered the sintering temperature and promoted the

  20. Theoretical characterization of the BN and BP coronenes by IR, Raman, and UV-VIS spectra

    Science.gov (United States)

    de Abreu, Leandro; López-Castillo, Alejandro

    2012-07-01

    Boron-nitrogen coronene (BNC) and boron-phosphorous coronene (BPC), not yet synthesized molecules and of possible interest for material science, are composed of six condensed rings of borazine and boraphosphabenzene molecules, respectively. They are similar to the carbon coronene molecule (CC). Moreover, CC and BNC are isoelectronic and the BPC is formally isoelectronic with respect to other coronenes, if only the valence electrons are considered. In this work, the BNC and BPC were theoretically characterized using IR, Raman, and UV-VIS spectroscopies. The coronenes studied have D6h and D3h symmetries for carbon and boron compounds, respectively. The calculated vibrational and electronic spectra for the CC are in good agreement with the experimental data, indicating that the calculations for BNC and BPC will be useful to identify these compounds, when synthesized. The main vibrational modes of the CC, BNC, and BPC are correlated. However, the BPC vibrational frequencies are substantially lower than the CC and BNC ones. The electronic ground state studies showed that the BPC has intermediate characteristics between the CC and BNC.

  1. Cyber security risk evaluation of a nuclear I and C using BN and ET

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jin Soo; Heo, Gyun Young [Dept. of Nuclear Engineering, Kyung Hee University, Yongin (Korea, Republic of); Son, Han Seong [Computer and Game Science, Joongbu University, Geumsan (Korea, Republic of)

    2017-04-15

    Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks.

  2. Cyber Security Risk Evaluation of a Nuclear I&C Using BN and ET

    Directory of Open Access Journals (Sweden)

    Jinsoo Shin

    2017-04-01

    Full Text Available Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks.

  3. Superhydrophobic hBN-Regulated Sponges with Excellent Absorbency Fabricated Using a Green and Facile Method

    National Research Council Canada - National Science Library

    Ying Zhou; Yao Wang; Tengfei Liu; Gang Xu; Guangming Chen; Huayi Li; Lichun Liu; Qiqi Zhuo; Jiaoxia Zhang; Chao Yan

    2017-01-01

    .... This superhydrophobic sponge (with a contact angle >150°) exhibits excellent absorption performance for oils and organic solvents, including good selectivity, high capacity (up to 175 g[ANO TELEIA]g-1...

  4. Dicty_cDB: FC-BN21 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago truncat...BC26G02 of cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago truncatula (barrel

  5. Dicty_cDB: FC-BN14 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available of cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago...clone MtBC26G02 of cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago truncatula

  6. İbn Battuta'ya Göre Güneydoğu Asya Ülkeleri

    OpenAIRE

    Göksoy, İsmail Hakkı

    2002-01-01

    Ibn Battuta, one of the famous Muslim traveller of the XIVth century, had travelled over the most of the Muslim countries of his time, and while going to China from India for a mission called at some of the harbour cities of Southeast Asia. This paper essentially deals with the extent and importance of his accounts based on his trips and observations in his book of travel with regard to the harbour cities and other places visited by him in Southeast Asia. While sailing through Samudra-Pasai, ...

  7. Structural, electronic and magnetic properties of chevron-type graphene, BN and BC{sub 2}N nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, T.; Azevedo, S. [Departamento de Física/CCEN, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900 João Pessoa, PB (Brazil); Kaschny, J.R. [Instituto Federal da Bahia-Campus Vitória da Conquista, Caixa Postal 3150, 45075-265 Vitória da Conquista, BA (Brazil)

    2017-04-15

    Graphene nanoribbons are predicted to be essential components in future nanoelectronics. The size, edge type, arrangement of atoms and width of nanoribbons drastically change their properties. Boronnitrogencarbon nanoribbons properties are not fully understood so far. In the present contribution it was investigated the structural, electronic and magnetic properties of chevron-type carbon, boron nitride and BC{sub 2}N nanoribbons, using first-principles calculations. The results indicate that the structural stability is closely related to the discrepancies in the bond lengths, which can induce structural deformations and stress. Such nanoribbons present a wide range of electronic behaviors, depending on their composition and particularities of the atomic arrangement. A net magnetic moment is found for structures that present carbon atoms at the nanoribbon borders. Nevertheless, the calculated magnetic moment depends on the peculiarities of the symmetric arrangement of atoms and imbalance of carbon atoms between different sublattices. It was found that all structures which have a significant energy gap do not present magnetic moment, and vice-versa. Such result indicates the strong correlation between the electronic and magnetic properties of the chevron-type nanoribbons. - Highlights: • Small discrepancies between distinct bond lengths can influence the formation energy of the BC{sub 2}N nanoribbons. • The electronic behavior of the BC{sub 2}N chevron-type nanoribbons depends on the atomic arrangement and structural symmetries. • There is a strong correlation between the electronic and magnetic properties for the BC{sub 2}N structures.

  8. Creep of Sylramic-iBN Fiber Tows at Elevated Temperature in Air and in Silicic Acid-Saturated Steam

    Science.gov (United States)

    2015-06-01

    fairly chemically inert, but has little to no mobility of dislocations, resulting in no plastic deformation. Because plastic deformation is an energy...ancient Egyptians, where their renowned straw -reinforced clay-bricks trumped over the traditional clay brick. The straw acted as a reinforcement medium...crystalline ceramic, stress concentrations cannot be relieved by plastic deformation (except, to some degree, at high temperatures) and thus the

  9. The Analysis of the System of special water purification of Beloyarskaya Nuclear Power Plant unit BN-800

    Science.gov (United States)

    Valtseva, A. I.; Bibik, I. S.

    2017-11-01

    This article discusses how the latest system of special water purification KPF-30, designed specifically for the fourth power unit of Beloyarskaya nuclear power plant, which has a number of advantages over other water purification systems as chemical-physical and technical-economic, environmental, and other industrial indicators. The scheme covered in this article systems of special water purification involves the use of a hydrocyclone at the preliminary stage of water treatment, as a worthy alternative to ion-exchange filters, which can significantly reduce the volume of toxic waste. The world community implements the project of closing the nuclear fuel cycle, there is a need to improve the reliability of the equipment for safe processes and development of critical and supercritical parameters in the nuclear industry. Essentially, on operated NPP units, the only factor that can cost-effectively optimize to improve the reliability of equipment is the water chemistry. System KPF30 meets the principles and criteria of ecological safety, demonstrating the justification for reagent less method of water treatment on the main stages, in which no formation of toxic wastes, leading to irreversible consequences of environmental pollution and helps to conserve water.

  10. 13,14B(n, γ) via Coulomb Dissociation for Nucleosynthesis towards the r-Process

    Science.gov (United States)

    Altstadt, S. G.; Adachi, T.; Aksyutina, Y.; Alcantara, J.; Alvarez-Pol, H.; Ashwood, N.; Atar, L.; Aumann, T.; Avdeichikov, V.; Barr, M.; Beceiro, S.; Bemmerer, D.; Benlliure, J.; Bertulani, C. A.; Boretzky, K.; Borge, M. J. G.; Burgunder, G.; Caamano, M.; Caesar, C.; Casarejos, E.; Catford, W.; Cederkäll, J.; Chakraborty, S.; Chartier, M.; Chulkov, L.; Cortina-Gil, D.; Datta Pramanik, U.; Diaz Fernandez, P.; Dillmann, I.; Elekes, Z.; Enders, J.; Ershova, O.; Estrade, A.; Farinon, F.; Fraile, L. M.; Freer, M.; Freudenberger, M.; Fynbo, H. O. U.; Galaviz, D.; Geissel, H.; Gernhäuser, R.; Göbel, K.; Golubev, P.; Gonzalez Diaz, D.; Hagdahl, J.; Heftrich, T.; Heil, M.; Heine, M.; Heinz, A.; Henriques, A.; Holl, M.; Holt, J. D.; Ickert, G.; Ignatov, A.; Jakobsson, B.; Johansson, H. T.; Jonson, B.; Kalantar-Nayestanaki, N.; Kanungo, R.; Kelic-Heil, A.; Knöbel, R.; Kröll, T.; Krücken, R.; Kurcewicz, J.; Kurz, N.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Lepyoshkina, O.; Machado, J.; Marganiec, J.; Maroussov, V.; Menéndez, J.; Mostazo, M.; Movsesyan, A.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Perea, A.; Pietri, S.; Plag, R.; Prochazka, A.; Rahaman, A.; Rastrepina, G.; Reifarth, R.; Ribeiro, G.; Ricciardi, M. V.; Rigollet, C.; Riisager, K.; Röder, M.; Rossi, D.; Sanchez del Rio, J.; Savran, D.; Scheit, H.; Schwenk, A.; Simon, H.; Simonis, J.; Sonnabend, K.; Sorlin, O.; Stoica, V.; Streicher, B.; Taylor, J.; Tengblad, O.; Terashima, S.; Thies, R.; Togano, Y.; Uberseder, E.; Van de Walle, J.; Velho, P.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Weigand, M.; Wheldon, C.; Wilson, G.; Wimmer, C.; Winfield, J. S.; Woods, P.; Yakorev, D.; Zhukov, M. V.; Zilges, A.; Zoric, M.; Zuber, K.

    2014-06-01

    Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.

  11. Synthesis and characterization of c-BN films prepared by ion beam assisted deposition and triode sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ben el Mekki, M.; Djouadi, M.A.; Mortet, V.; Guiot, E. [ENSAM, Cluny (France). Lab. Bourguignon des Mater. et Procedes; Nouet, G. [LERMAT, ISMRA, Caen (France); Mestres, N. [Institut de Ciencia de Materials de Barcelona, (CSIC), E-08193, Bellaterra (Spain)

    1999-11-01

    Boron nitride films deposited on unheated c-Si substrates by ion beam assisted deposition (IBAD) and triode sputtering (TS) techniques are studied. The composition, microstructure and crystallinity of the films obtained by the two techniques are compared The methods of characterization used in this study are: X-ray photo-electron, infrared, and Raman spectroscopies. High-resolution cross sectional TEM is used to confirm the optical results. In the case of films prepared by IBAD, the ion energy was 350-500 eV. The films were prepared from different gas mixtures of nitrogen and argon, boron was supplied by evaporation of elemental boron. TS films were prepared with 100% of nitrogen, the boron was supplied by sputtering a pure boron target. This study shows that, in comparison with TS samples, IBAD samples have higher chemical and physical stability. The particle-size dependence of frequencies and damping of optical phonons is studied for all samples from the analysis of Raman scattering and infrared spectra. A very important difference between the particle-sizes of IBAD and TS samples is observed. A progressive chemical etching by nitric acid at 80 C combined with infrared characterization was successfully performed on IBAD samples deposited at low ion flux and announces a mixture of sp{sup 2} and sp{sup 3} phases with high content of sp{sup 3} structure. All results are in full agreements with TEM results. (orig.)

  12. Weak interactions in Graphane/BN systems under static electric fields—A periodic ab-initio study

    Energy Technology Data Exchange (ETDEWEB)

    Steinkasserer, Lukas Eugen Marsoner, E-mail: marsoner@zedat.fu-berlin.de [Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin (Germany); MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, 6140 Wellington (New Zealand); Gaston, Nicola [MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, 6140 Wellington (New Zealand); Paulus, Beate [Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin (Germany)

    2015-04-21

    Ab-initio calculations via periodic Hartree-Fock (HF) and local second-order Møller-Plesset perturbation theory (LMP2) are used to investigate the adsorption properties of combined Graphane/boron nitride systems and their response to static electric fields. It is shown how the latter can be used to alter both structural as well as electronic properties of these systems.

  13. Evaluations of parameters peculiar to the third group nitrides: BN, AIN, GaN and InN

    CERN Document Server

    Davydov, S Y

    2002-01-01

    The estimations of dielectric, optical electrooptical, magnetic and phonon characteristics of XN (X = B, Al, Ga, In) crystals are obtained by means of simple methods using both quantum mechanics and semiempirical approaches. The values of deformation potentials and magnetic susceptibility these nitrides are defined. The calculation results are compared with experimental data and data obtained by other authors

  14. Thermal Conductivity Enhancement by Optical Phonon Sub-Band Engineering of Nanostructures Based on C and BN

    Science.gov (United States)

    2002-01-01

    some different analytical approaches to the problem [11,12] an d wonderful reviews [13-15] . The purpose of this research is to estimate the maximum TC...However, in order to evaluate prospects of more aggressive goals fully exploiting the claimed potential, much more research work is needed to provide a...Systems for cooling would be much more attractiv e for DoD Application s lF~ Fluidic Based Cooling Usin g Channels 4 Impact 1 : for Heat Management

  15. Studies on the sythesis of c-BN layers with ECWR-PACVD and borane- ammonia as educt material

    CERN Document Server

    Schumacher, A

    2000-01-01

    Boron nitride films were deposited by controlled plasma assisted chemical vapor deposition (PACVD) on the basis of borane-ammonia (BH sub 3 NH sub 3) as B- and N- supplier. Having a high vapor pressure, this white crystalline solid of less toxicity in comparision to generally used boron precursors can easily be transferred into the gas phase by moderate heating. Together with argon as working gas the BH sub 3 NH sub 3 -vapor is led into a two-circuit plasma source utilizing the electron cyclotron wave resonance technique (ECWR) for ionization and dissoziation of the gas mixture by electron impact in the low pressure range (propor to 10 mbar). For a precise adjustment of the energy of the ionic plasma species arriving at the growing film, an r.f.-diode circuit is superimposed to the discharge. Since for a controlled film deposition by PACVD a stationary plasma composition is mandatory, the evaporation characteristics of the reactant source was determined primarily. Therefore the evolution of the plasma and the...

  16. Anisotropy of x-ray reflectivity: chemical and structural effects on K-shell excitations in hexagonal BN crystal

    CERN Document Server

    Filatova, E O

    2002-01-01

    The experimental investigation of the B and N K-reflection spectra using both s-polarized synchrotron radiation and unpolarized radiation for different crystal orientations with respect to the electric field vector E was carried out. The absorption spectra calculated from the reflection spectra using Kramers-Kronig analysis are presented. A strong orientation dependence of both reflection and absorption spectra is exhibited. Analysis of the orientation dependences of the x-ray reflection and absorption spectra near both edges strongly supports a possibility of tracing the role of each excitation canal in the formation of fine structure. The high sensitivity of the reflection spectra fine structure to the vibronic interaction connected with Jahn-Teller distortions as well to the core-hole relaxation is discussed. A very strong dependence of the absolute values of the reflectivity on planar crystal anisotropy was discovered.

  17. ARİSTOTELES, STOACILAR VE İBN RÜŞD'ÜN KIYASA BAKIŞI

    OpenAIRE

    ÇAPAK, İbrahim

    2009-01-01

    This paper examines the main ideas on syllogism in the logical systems of Aristotle, Stoics and Avveros. Aristotle, is the firts philosopher who formulated a system of logic. . He influenced many philosophers in this respect in the subsequent centuries. Aristotle gives an extreme importance to establishing the proof through syllogism which consists of two propositions or premises and conclusion. Aristotle investigates categorical and component syllogistic but not conditional one. According to...

  18. Its ovr b/n u n me: technology use, attachment styles, and gender roles in relationship dissolution.

    Science.gov (United States)

    Weisskirch, Robert S; Delevi, Raquel

    2012-09-01

    Relationship dissolution now occurs through technologies like text messaging, e-mail, and social networking sites (SNS). Individuals who experience relationship dissolution via technology may differ in their attachment pattern and gender role attitudes from those who have not had that experience. One hundred five college students (males=21 and females=84) completed an online questionnaire about technology-mediated breakups, attachment style, and gender role attitudes. More than a quarter of the sample had experienced relationship dissolution via technology. Attachment anxiety predicted those subject to technology-mediated breakups. Attachment avoidance and less traditional gender roles were associated with increased likelihood of technology use in relationship dissolution. Implications are discussed in regards to future research and practice.

  19. Tümevarım Meselesi -İbn Sînâ Merkezli Yeni Bir Okuma-

    OpenAIRE

    UYANIK, Mevlüt

    2015-01-01

    The purpose of philosophy is to achieve happiness. Logic is just like a key leading man towards this joy in philosophy. Logic helps us to reach knowledge on a standart of rationality and coherence by following the path of the individual to the universal and the known through the unknown. An exact correspondence between thoughts and words occur only with correct principles of reasoning. Therefore, logic plays a great role in philosophy. The scientific method ‘induction’ in the new age philosop...

  20. Bulimia nervosa-nonpurging subtype: closer to the bulimia nervosa-purging subtype or to binge eating disorder?

    Science.gov (United States)

    Jordan, Jennifer; McIntosh, Virginia V W; Carter, Janet D; Rowe, Sarah; Taylor, Kathryn; Frampton, Christopher M A; McKenzie, Janice M; Latner, Janet; Joyce, Peter R

    2014-04-01

    DSM-5 has dropped subtyping of bulimia nervosa (BN), opting to continue inclusion of the somewhat contentious diagnosis of BN-nonpurging subtype (BN-NP) within a broad BN category. Some contend however that BN-NP is more like binge eating disorder (BED) than BN-P. This study examines clinical characteristics, eating disorder symptomatology, and Axis I comorbidity in BN-NP, BN-P, and BED groups to establish whether BN-NP more closely resembles BN-P or BED. Women with BN-P (n = 29), BN-NP (n = 29), and BED (n = 54) were assessed at baseline in an outpatient psychotherapy trial for those with binge eating. Measures included the Structured Clinical Interviews for DSM-IV, Eating Disorder Examination, and Eating Disorder Inventory-2. The BN-NP subtype had BMIs between those with BN-P and BED. Both BN subtypes had higher Restraint and Drive for Thinness scores than BED. Body Dissatisfaction was highest in BN-NP and predicted BN-NP compared to BN-P. Higher Restraint and lower BMI predicted BN-NP relative to BED. BN-NP resembled BED with higher lifetime BMIs; and weight-loss clinic than eating disorder clinic attendances relative to the BN-P subtype. Psychiatric comorbidity was comparable except for higher lifetime cannabis use disorder in the BN-NP than BN-P subtype These results suggest that BN-NP sits between BN-P and BED however the high distress driving inappropriate compensatory behaviors in BN-P requires specialist eating disorder treatment. These results support retaining the BN-NP group within the BN category. Further research is needed to determine whether there are meaningful differences in outcome over follow-up. Copyright © 2013 Wiley Periodicals, Inc.

  1. Does Entry Route Really Affect Academic Outcome? Academic Achievement of Traditional versus Non Traditional Entrants to BN(Hons) Pre-Registration Nursing Programmes

    Science.gov (United States)

    Brimble, Mandy J.

    2015-01-01

    International trends for pre-registration nurse education at degree level alongside "widening access" initiatives mean that academic achievement of students entering via different educational routes is of interest to both higher and further education institutions. This article examines the academic achievement of students undertaking a…

  2. Water on BN doped benzene: A hard test for exchange-correlation functionals and the impact of exact exchange on weak binding

    CERN Document Server

    Al-Hamdani, Yasmine S; von Lilienfeld, O Anatole; Michaelides, Angelos

    2016-01-01

    Density functional theory (DFT) studies of weakly interacting complexes have recently focused on the importance of van der Waals dispersion forces whereas, the role of exchange has received far less attention. Here, by exploiting the subtle binding between water and a boron and nitrogen doped benzene derivative (1,2-azaborine) we show how exact exchange can alter the binding conformation within a complex. Benchmark values have been calculated for three orientations of the water monomer on 1,2-azaborine from explicitly correlated quantum chemical methods, and we have also used diffusion quantum Monte Carlo. For a host of popular DFT exchange-correlation functionals we show that the lack of exact exchange leads to the wrong lowest energy orientation of water on 1,2-azaborine. As such, we suggest that a high proportion of exact exchange and the associated improvement in the electronic structure could be needed for the accurate prediction of physisorption sites on doped surfaces and in complex organic molecules. ...

  3. Stealing a ride on a comet to the sun: spaceship's 10-year, 4bn mile odyssey: European craft's audacious trip will give insight into our origins

    CERN Multimedia

    Radford, T

    2003-01-01

    "Some time in the next two weeks, European scientists hope to launch a spaceship the size of a delivery van and lob it across more than 4 billion miles of space to rendezvous 10 years from now with a dark lump of rock and ice the size of a city block" (1 page).

  4. Gene Silencing of BnTT10 Family Genes Causes Retarded Pigmentation and Lignin Reduction in the Seed Coat of Brassica napus

    Science.gov (United States)

    Zhang, Kai; Lu, Kun; Qu, Cunmin; Liang, Ying; Wang, Rui; Chai, Yourong; Li, Jiana

    2013-01-01

    Yellow-seed (i.e., yellow seed coat) is one of the most important agronomic traits of Brassica plants, which is correlated with seed oil and meal qualities. Previous studies on the Brassicaceae, including Arabidopsis and Brassica species, proposed that the seed-color trait is correlative to flavonoid and lignin biosynthesis, at the molecular level. In Arabidopsis thaliana, the oxidative polymerization of flavonoid and biosynthesis of lignin has been demonstrated to be catalyzed by laccase 15, a functional enzyme encoded by the AtTT10 gene. In this study, eight Brassica TT10 genes (three from B. napus, three from B. rapa and two from B. oleracea) were isolated and their roles in flavonoid oxidation/polymerization and lignin biosynthesis were investigated. Based on our phylogenetic analysis, these genes could be divided into two groups with obvious structural and functional differentiation. Expression studies showed that Brassica TT10 genes are active in developing seeds, but with differential expression patterns in yellow- and black-seeded near-isogenic lines. For functional analyses, three black-seeded B. napus cultivars were chosen for transgenic studies. Transgenic B. napus plants expressing antisense TT10 constructs exhibited retarded pigmentation in the seed coat. Chemical composition analysis revealed increased levels of soluble proanthocyanidins, and decreased extractable lignin in the seed coats of these transgenic plants compared with that of the controls. These findings indicate a role for the Brassica TT10 genes in proanthocyanidin polymerization and lignin biosynthesis, as well as seed coat pigmentation in B. napus. PMID:23613820

  5. Natural Anti-Infective Pulmonary Proteins: In Vivo Cooperative Action of Surfactant Protein SP-A and the Lung Antimicrobial Peptide SP-BN.

    Science.gov (United States)

    Coya, Juan Manuel; Akinbi, Henry T; Sáenz, Alejandra; Yang, Li; Weaver, Timothy E; Casals, Cristina

    2015-08-15

    The anionic antimicrobial peptide SP-B(N), derived from the N-terminal saposin-like domain of the surfactant protein (SP)-B proprotein, and SP-A are lung anti-infective proteins. SP-A-deficient mice are more susceptible than wild-type mice to lung infections, and bacterial killing is enhanced in transgenic mice overexpressing SP-B(N). Despite their potential anti-infective action, in vitro studies indicate that several microorganisms are resistant to SP-A and SP-B(N). In this study, we test the hypothesis that these proteins act synergistically or cooperatively to strengthen each other's microbicidal activity. The results indicate that the proteins acted synergistically in vitro against SP-A- and SP-B(N)-resistant capsulated Klebsiella pneumoniae (serotype K2) at neutral pH. SP-A and SP-B(N) were able to interact in solution (Kd = 0.4 μM), which enabled their binding to bacteria with which SP-A or SP-B(N) alone could not interact. In vivo, we found that treatment of K. pneumoniae-infected mice with SP-A and SP-B(N) conferred more protection against K. pneumoniae infection than each protein individually. SP-A/SP-B(N)-treated infected mice showed significant reduction of bacterial burden, enhanced neutrophil recruitment, and ameliorated lung histopathology with respect to untreated infected mice. In addition, the concentrations of inflammatory mediators in lung homogenates increased early in infection in contrast with the weak inflammatory response of untreated K. pneumoniae-infected mice. Finally, we found that therapeutic treatment with SP-A and SP-B(N) 6 or 24 h after bacterial challenge conferred significant protection against K. pneumoniae infection. These studies show novel anti-infective pathways that could drive development of new strategies against pulmonary infections. Copyright © 2015 by The American Association of Immunologists, Inc.

  6. İBN HAZM'A GÖRE HZ. PEYGAMBERDEN SONRA EFDALİYYET/ÜSTÜNLÜK DURUMU VE SAHABE

    OpenAIRE

    Yönem, Ahmet

    2015-01-01

    Just as the imamate theory of every communion depends on different theoretic grounds on Islamic political ideas' taking form, historians of Islamic Communions have also been influential on this theory with their views and ideas. These discussions having emerged on the Prophet's death keeps their importance even today. The supremacy idea (efdaliyyet) is the notion which upholds that the the most preeminent person should have the imamate position. Mefdul, who comes after efdal, accept...

  7. Stark shift and electric-field-induced dissociation of excitons in monolayer MoS2 and hBN/MoS2 heterostructures

    DEFF Research Database (Denmark)

    Haastrup, Sten; Latini, Simone; Bolotin, Kirill

    2016-01-01

    Efficient conversion of photons into electrical current in two-dimensional semiconductors requires, as a first step, the dissociation of the strongly bound excitons into free electrons and holes. Here we calculate the dissociation rates and energy shift of excitons in monolayer MoS2 as a function...

  8. Dialektisch-Behaviorale Therapie für jugendliche Patientinnen mit Anorexia und Bulimia nervosa (DBT-AN/BN) - eine Pilotstudie

    OpenAIRE

    Salbach, Harriet; Klinkowski, Nora; Pfeiffer, Ernst; Lehmkuhl, Ulrike; Korte, Alexander

    2007-01-01

    Die Dialektisch-Behaviorale Therapie (DBT) wurde ursprünglich von Linehan (1993a, b) entwickelt. Miller et al. (1997) modifizierten das Konzept erfolgreich für suizidale jugendliche Patienten mit komorbiden Symptomen einer instabilen Persönlichkeitsstörung. Mittlerweile wird die DBT im Erwachsenenbereich auch bei anderen Patientengruppen erfolgreich eingesetzt. Das vorrangige Ziel der Studie ist die Überprüfung der Effektivität von DBT bei stationären jugendlichen Patient...

  9. Hedvábná stezka jako nástroj čínské zahraniční politiky

    OpenAIRE

    Fraňková, Lenka

    2017-01-01

    The topic of this bachelor degree thesis is The Silk road, an instrument of China's foreign affairs. The main purpose is to identify, evaluate and determine China's current and past foreign politics impact on the Silk road trading to arrange and exchange goods and also to tie together diplomatic's relations between China and Asia.

  10. Areva At December 31, 2010: Revenue rises to euros 9.104 bn: + 6.7% Backlog rises to euros 44.2 bn: + 2.0%; Areva au 31 decembre 2010: Croissance du chiffre d'affaires a 9104 Meuros: + 6,7 % Croissance du carnet de commandes a 44,2 Mdseuros: + 2,0 %

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    In 2010, AREVA's consolidated revenue rose 6.7% to 9.104 billion euros (+ 5.1% growth like-for-like) compared with 2009. The Mining-Front End Business Group and the Reactors and Services Business Group were the leading growth engines, with revenue growth of 6.7% and 8.9% respectively. Foreign exchange had a positive impact of 141 million euros and the scope of consolidation remained stable over the period. Fourth quarter 2010 revenue totaled 2.936 billion euros, an increase of 7.7% (+4.8% like-for-like) compared with the fourth quarter of 2009, due in particular to 18.1% growth in the Mining-Front End BG. Foreign exchange had an impact of 58 million euros over the period. The group's backlog came to 44.2 billion euros at December 31, 2010, up 2.0% in relation to December 31, 2009. The backlog grew in the Mining-Front End and Renewable Energies BGs. Installed Base Business operations held up well, replenishing the backlog for the Reactors and Services BG. The agreement with the Indian utility NPCIL concerning the construction of two EPR{sup TM} reactors and fuel cycle supply for 25 years was not recorded in the backlog at December 31, 2010. The change in the Back End BG's backlog reflects the implementation of contracts signed in previous years. Nearly one billion euros in letters of intent signed in 2010 with US utilities corresponding to pre-sold production from the future enrichment plant were not included in the Mining-Front End BG's backlog. The backlog of the Mining-Front End BG came to 28.902 billion euros at December 31, 2010, up 4% compared with the end of 2009. Contracts won in 2010 include: - the 10-year uranium supply contract with CGNPC for approximately 3.5 billion dollars; - several other multi-year contracts signed in the front end of the cycle with US and Asian utilities. For the full year of 2010, the Mining-Front End BG reported revenue of 3.704 billion euros, an increase of 6.7% on a reported basis and of 4.2% LFL. Foreign exchange had a positive impact of 84 million euros. - In Mining, revenue continued to benefit from the increase in AREVA's average uranium sales prices (+5%) and in volumes sold. In addition, gold revenue was up more than 80% compared with 2009. - In Enrichment, revenue was stable compared with 2009. - In Fuel, the drop in volumes reflecting the postponement of deliveries in France was offset by an increase in ancillary activities revenue (components and services) compared with 2009. The backlog for the Reactors and Services BG came to 7.290 billion euros at December 31, 2010. The leading orders booked in the second half of the year were as follows: - an engineering contract from US utility Tennessee Valley Authority to study conditions for completion of unit 1 of the Bellefonte power plant in northern Alabama; - industrial prototype design studies for the CEA for the Generation IV ASTRID reactor; - the start of design, engineering and safety studies for the Indian utility NPCIL under the agreement concerning the construction of two EPR{sup TM} reactors at the Jaitapur site and fuel supply for 25 years, with commercial negotiations expected to be brought to a successful conclusion in 2011. Revenue for the Reactors and Services BG was up 8.9% in 2010 (+7.8% LFL) to 3.384 billion euros. Foreign exchange had a positive impact of 39 million euros. - The New Build business was up due to significant progress on major reactor construction projects. - Installed Base Services were up sharply due to buoyant business in component replacement, the increase in power plant modernization and up-rating operations in Europe, and the large amount of work performed in the United States on unit outages. The backlog for the Back End BG came to 6.056 billion euros at December 31, 2010. The BG continued to pursue its international development over the year. In particular, it signed MOX fuel fabrication contracts and a contract with the US Department of Energy for the training of future operators of the MOX Fuel Fabrication Facility in Savannah River, South Carolina. Revenue for the Back End BG totaled 1.709 billion euros in 2010, up 4.4% compared with the same period in 2009 (+4.0% LFL), due to a higher level of business at the La Hague plant than in 2009. The backlog for the Renewable Energies BG came to 1.843 billion euros at December 31, 2010. The most significant contract wins during the year were: - a 400-million euro contract from Trianel, an association of German utilities, to deliver forty 5 MW M5000 turbines for the Borkum West II offshore wind farm; - a contract concerning the modernization of cogeneration units in ten sugar cane plants in Brazil with the independent power company Hidrotermica. The Renewable Energies BG reported revenue of 150 million euros for the full year of 2010, down 10.9% on a reported basis compared with 2009 (-16.9% LFL). The downturn in Biomass business in Brazil and Europe was partially offset by rising Offshore Wind business during the period. The fourth quarter 2010 recovery in the Biomass business was confirmed with the signature of significant contracts, particularly in Brazil

  11. The validity and utility of subtyping bulimia nervosa.

    Science.gov (United States)

    van Hoeken, Daphne; Veling, Wim; Sinke, Sjoukje; Mitchell, James E; Hoek, Hans W

    2009-11-01

    To review the evidence for the validity and utility of subtyping bulimia nervosa (BN) into a purging (BN-P) and a nonpurging subtype (BN-NP), and of distinguishing BN-NP from binge eating disorder (BED), by comparing course, complications, and treatment. A literature search of psychiatry databases for studies published in peer-reviewed journals that used the DSM-definitions of BN and BED, and included both individuals with BN-NP and individuals with BN-P and/or BED. Twenty-three studies compared individuals with BN-NP (N = 671) to individuals with BN-P (N = 1795) and/or individuals with BED (N = 1921), two of which reported on course, 12 on comorbidity and none on treatment response-the indicators for validity and clinical utility. The differences found were mainly quantitative rather than qualitative, suggesting a gradual difference in severity from BN-P (most severe) through BN-NP to BED (least severe). None of the comparisons provided convincing evidence for the validity or utility of the BN-NP diagnosis. Three options for the position of BN-NP in DSM-V were suggested: (1) maintaining the BN-NP subtype, (2) dropping nonpurging compensatory behavior as a criterion for BN, so that individuals currently designated as having BN-NP would be designated as having BED, and (3) including BN-NP in a broad BN category.

  12. Saylorville Stage 3 Contract Completion Report: Testing of Priority 1 Archaeological Sites 1980-1981.

    Science.gov (United States)

    1982-02-01

    site excavation has been accomplished along the Des Moines River corridor between Fraser on the north and the Knoxville- Pella locality on the south...Shalom), 13PK175 (Bastille Bottoms), 13PK265 ( Brassica Bench), 13BN12 (Carl Rose Site), 13BN103 (Logansport Site), 13BN121 (Sparks Site), and 13BN125...Gidel Kiln), 13MA113 ( Pella - Welch Kiln), 13BN111 (Noah Creek Kiln), 13BN120 (Moingona Pottery Works), 13BN131 (Franklin Kiln), 13BN132 (Flintstone

  13. Dynamic study of yeast species and Saccharomyces cerevisiae strains during the spontaneous fermentations of Muscat blanc in Jingyang, China.

    Science.gov (United States)

    Wang, Chunxiao; Liu, Yanlin

    2013-04-01

    The evolution of yeast species and Saccharomyces cerevisiae genotypes during spontaneous fermentations of Muscat blanc planted in 1957 in Jingyang region of China was followed in this study. Using a combination of colony morphology on Wallerstein Nutrient (WLN) medium, sequence analysis of the 26S rDNA D1/D2 domain and 5.8S-ITS-RFLP analysis, a total of 686 isolates were identified at the species level. The six species identified were S. cerevisiae, Hanseniaspora uvarum, Hanseniaspora opuntiae, Issatchenkia terricola, Pichia kudriavzevii (Issatchenkia orientalis) and Trichosporon coremiiforme. This is the first report of T. coremiiforme as an inhabitant of grape must. Three new colony morphologies on WLN medium and one new 5.8S-ITS-RFLP profile are described. Species of non-Saccharomyces, predominantly H. opuntiae, were found in early stages of fermentation. Subsequently, S. cerevisiae prevailed followed by large numbers of P. kudriavzevii that dominated at the end of fermentations. Six native genotypes of S. cerevisiae were determined by interdelta sequence analysis. Genotypes III and IV were predominant. As a first step in exploring untapped yeast resources of the region, this study is important for monitoring the yeast ecology in native fermentations and screening indigenous yeasts that will produce wines with regional characteristics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Multiple NUCLEAR FACTOR Y transcription factors respond to abiotic stress in Brassica napus L.

    Directory of Open Access Journals (Sweden)

    Li Xu

    Full Text Available Members of the plant NUCLEAR FACTOR Y (NF-Y family are composed of the NF-YA, NF-YB, and NF-YC subunits. In Brassica napus (canola, each of these subunits forms a multimember subfamily. Plant NF-Ys were reported to be involved in several abiotic stresses. In this study, we demonstrated that multiple members of thirty three BnNF-Ys responded rapidly to salinity, drought, or ABA treatments. Transcripts of five BnNF-YAs, seven BnNF-YBs, and two BnNF-YCs were up-regulated by salinity stress, whereas the expression of thirteen BnNF-YAs, ten BnNF-YBs, and four BnNF-YCs were induced by drought stress. Under NaCl treatments, the expression of one BnNF-YA10 and four NF-YBs (BnNF-YB3, BnNF-YB7, BnNF-YB10, and BnNF-YB14 were greatly increased. Under PEG treatments, the expression levels of four NF-YAs (BnNF-YA9, BnNF-YA10, BnNF-YA11, and BnNF-YA12 and five NF-YBs (BnNF-YB1, BnNF-YB8, BnNF-YB10, BnNF-YB13, and BnNF-YB14 were greatly induced. The expression profiles of 20 of the 27 salinity- or drought-induced BnNF-Ys were also affected by ABA treatment. The expression levels of six NF-YAs (BnNF-YA1, BnNF-YA7, BnNF-YA8, BnNF-YA9, BnNF-YA10, and BnNF-YA12 and seven BnNF-YB members (BnNF-YB2, BnNF-YB3, BnNF-YB7, BnNF-YB10, BnNF-YB11, BnNF-YB13, and BnNF-YB14 and two NF-YC members (BnNF-YC2 and BnNF-YC3 were greatly up-regulated by ABA treatments. Only a few BnNF-Ys were inhibited by the above three treatments. Several NF-Y subfamily members exhibited collinear expression patterns. The promoters of all stress-responsive BnNF-Ys harbored at least two types of stress-related cis-elements, such as ABRE, DRE, MYB, or MYC. The cis-element organization of BnNF-Ys was similar to that of Arabidopsis thaliana, and the promoter regions exhibited higher levels of nucleotide sequence identity with Brassica rapa than with Brassica oleracea. This work represents an entry point for investigating the roles of canola NF-Y proteins during abiotic stress responses and provides

  15. Pseudomorphic Semiconducting Heterostructures from Combinations of AIN, GaN and Selected SiC Polytypes: Theoretical Advancement and its Coordination with Experimental Studies of Nucleation, Growth, Characterization and Device Development.

    Science.gov (United States)

    1992-12-01

    c-BN) corresponding to diamond, and a rare hexagonal wurtzite structure (w-BN) which corresponds to Lonsdaleite . The layered hexagonal structure is...structure (w-BN) corresponding to Lonsdaleite . The last two phases are metastable under normal environmental conditions. An amorphous phase (a-BN) is

  16. The validity and utility of subtyping bulimia nervosa

    NARCIS (Netherlands)

    van Hoeken, Daphne; Veling, Wim; Sinke, Sjoukje; Mitchell, James E.; Hoek, Hans W.

    2009-01-01

    Objective: To review the evidence for the validity and utility of subtyping bulimia nervosa (BN) into a purging (BN-P) and a nonpurging subtype (BN-NP), and of distinguishing BN-NP from binge eating disorder (BED), by comparing course, complications, and treatment. Method: A literature search of

  17. Ageing Effects on Microstructure, Mechanical Properties, and Fracture Behaviour of 9Cr-1.5Mo-1Co-VNbBN Martensitic Steel Welded Joint for High Temperature Application

    Czech Academy of Sciences Publication Activity Database

    Falat, L.; Homolová, V.; Čiripová, L.; Ševc, P.; Svoboda, Milan

    2017-01-01

    Roč. 2017, JAN (2017), č. článku 6824385. ISSN 1687-8434 Grant - others:AV ČR(CZ) SAV-15-11 Program:Bilaterální spolupráce Institutional support: RVO:68081723 Keywords : martensitic steel * Z-phase formation * creep-strength Subject RIV: JG - Metallurgy Impact factor: 1.299, year: 2016

  18. Tweaking subtype-selectivity and agonist efficacy at (S)-2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propionic acid (AMPA) receptors in a small series of BnTetAMPA analogues

    DEFF Research Database (Denmark)

    Wang, Shuang-Yan; Larsen, Younes; Navarrete, Cristina V.

    2016-01-01

    with the agonist binding domain (ABD) of GluA2 show that they induce full domain closure despite their low agonist efficacies. Trp767 in GluA2 ABD could be an important determinant for partial agonism of this compound series at AMPA receptors, since agonist efficacy also correlated with the location of the Trp767...

  19. Pseudomorphic Stabilization of Diamond on Non-Diamond Substrates. Part 1. Diamond Grown on Single Crystal Beryllium Oxide. Part 2. Anomalous Band Gap Behavior and Phase Stability of c-BN/Diamond Alloys

    Science.gov (United States)

    1992-10-12

    at (I13, 2/3, 0) and 0 at (i/3, 2/3, 3/8) or vice versa. This structure (Table I) is geometrically similar to Lonsdaleite (hexagonal diamond) and thus...thin crystal of Lonsdaleite with the ABAB... stacking sequence can be achieved in the early stages of diamond growth.- 4 .25 After the elimination of the

  20. İbn Haldun’un Siyaset Teorisi Ve Siyasal Sistem Sınıflandırması
    Political Theory And Politic System Classification Of Ibn Khaldun

    OpenAIRE

    Ali ÇİFTÇİ; YILMAZ, Nihat

    2013-01-01

    The past of the scientific works of administration methods is quiteold. The struggle of finding out the best one by examining politicalsystems comperatively were not only limited with the past. It has beencarried on until today. As well as the works that have been performed inWest since the Ancient Greek Period, The Islamic World have submittedmany precious works in aforementioned topic. One of those whosubmitted precious works for political theory and politic systemclassification was Ibn Kha...

  1. Seyahatnamelerde Hadîs Kültürü: İbn Battûta Örneği
    Hadith Culture in Travelogues: The Case of Ibn Battuta

    OpenAIRE

    MACİT, Yunus

    2012-01-01

    Books of Travels are one of the most important sources of Islamichistory and religious life; because they have important functions interms of their transport of the historical, geographical and socio-culturalcharacteristics of a certain time to the present day.Travelling is also an important tradition in Islamic culture;because of travelling is a good way to expand the horizons of knowledgeand experience.As it’s known, Ibn Battuta also known as Shams ad-Din (1304–1368 or 1369), was a Berber M...

  2. Control and Data Acquisitions System for the spanish Beamline (BM25) at the ESRF; Sistema de Control y Acquisicion de Datos para la Linea Espanola (BN25) del ESRF

    Energy Technology Data Exchange (ETDEWEB)

    Pereira Gonzalez, A.; Olalla Garcia, C.; Sanchez Sanz, J.; Castro, G. R.

    2005-07-01

    A new control and data acquisition system has been developed for BM25 Spanish Line at the ESRF. The system is based in VMEbus, Motorola PreP architecture and Linux Operating System and it's linked to a local ETHERNET network which provides the way of communicate with the servers (PC workstations). In these computers, the data are available for general usage in order to analyze them. The data acquisition consists of many channels connected to the VME crates mainly, independent between them, and fully programmable by drivers, CLUI's and GUI's interfaces, and a set of independent systems (embedded ones, PLCs, others) controlling the security aspects. This report is described in terms of their architecture, their electronic system to the process hard ware and the functionality and the application development facilities they provide using the software and the data acquisition. (Author) 18 refs.

  3. Comparing the potential renal protective activity of desferrioxamine B and the novel chelator desferrioxamine B-N-(3-hydroxyadamant-1-yl)carboxamide in a cell model of myoglobinuria.

    Science.gov (United States)

    Groebler, Ludwig K; Liu, Joe; Shanu, Anu; Codd, Rachel; Witting, Paul K

    2011-05-01

    Accumulating Mb (myoglobin) in the kidney following severe burns promotes oxidative damage and inflammation, which leads to acute renal failure. The potential for haem-iron to induce oxidative damage has prompted testing of iron chelators [e.g. DFOB (desferrioxamine B)] as renal protective agents. We compared the ability of DFOB and a DFOB-derivative {DFOB-AdAOH [DFOB-N-(3-hydroxyadamant-1-yl)carboxamide]} to protect renal epithelial cells from Mb insult. Loading kidney-tubule epithelial cells with dihydrorhodamine-123 before exposure to 100 μM Mb increased rhodamine-123 fluorescence relative to controls (absence of Mb), indicating increased oxidative stress. Extracellular Mb elicited a reorganization of the transferrin receptor as assessed by monitoring labelled transferrin uptake with flow cytometry and inverted fluorescence microscopy. Mb stimulated HO-1 (haem oxygenase-1), TNFα (tumour necrosis factor α), and both ICAM (intercellular adhesion molecule) and VCAM (vascular cell adhesion molecule) gene expression and inhibited epithelial monolayer permeability. Pre-treatment with DFOB or DFOB-AdAOH decreased Mb-mediated rhodamine-123 fluorescence, HO-1, ICAM and TNFα gene expression and restored monolayer permeability. MCP-1 (monocyte chemotactic protein 1) secretion increased in cells exposed to Mb-insult and this was abrogated by DFOB or DFOB-AdAOH. Cells treated with DFOB or DFOB-AdAOH alone showed no change in permeability, MCP-1 secretion or HO-1, TNFα, ICAM or VCAM gene expression. Similarly to DFOB, incubation of DFOB-AdAOH with Mb plus H2O2 yielded nitroxide radicals as detected by EPR spectroscopy, indicating a potential antioxidant activity in addition to metal chelation; Fe(III)-loaded DFOB-AdAOH showed no nitroxide radical formation. Overall, the chelators inhibited Mb-induced oxidative stress and inflammation and improved epithelial cell function. DFOB-AdAOH showed similar activity to DFOB, indicating that this novel low-toxicity chelator may protect the kidney after severe burns.

  4. Bilgi Ağları ve Kütüphanelerarası İşbirliği

    Directory of Open Access Journals (Sweden)

    Yaşar Tonta

    1987-09-01

    Full Text Available This paper is on library and Information networks and inter- library co-operation. Different types of networks, their features and struc- tures are briefly reviewed. Also mentioned are the local area netvvorks (LANs, whereby libraries can easily access national and intemational net- works such as JANET, EARN and BITNET. Among other things the func- tions of «intelligent gatevvays», online public access catalogues (OPAÇs and electrbnic mail facilities are explained. A few examples of interlibrary co- operation which have been originated from networks are given in the sec- ond part of the paper; the activities of the Centre for Bibliographic Infor­mation in Japan; the services of library co-operatives such as BLCMP and SWALCAP in the UK, and the way they work; and, the Linked Systems Project, which is the most advanced project of four networks (LC, WLN, RLIN and OCLC in this respect in the US.

  5. Anisotropic Hexagonal Boron Nitride Nanomaterials - Synthesis and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Han,W.Q.

    2008-08-01

    Boron nitride (BN) is a synthetic binary compound located between III and V group elements in the Periodic Table. However, its properties, in terms of polymorphism and mechanical characteristics, are rather close to those of carbon compared with other III-V compounds, such as gallium nitride. BN crystallizes into a layered or a tetrahedrally linked structure, like those of graphite and diamond, respectively, depending on the conditions of its preparation, especially the pressure applied. Such correspondence between BN and carbon readily can be understood from their isoelectronic structures [1, 2]. On the other hand, in contrast to graphite, layered BN is transparent and is an insulator. This material has attracted great interest because, similar to carbon, it exists in various polymorphic forms exhibiting very different properties; however, these forms do not correspond strictly to those of carbon. Crystallographically, BN is classified into four polymorphic forms: Hexagonal BN (h-BN) (Figure 1(b)); rhombohedral BN (r-BN); cubic BN (c-BN); and wurtzite BN (w-BN). BN does not occur in nature. In 1842, Balmain [3] obtained BN as a reaction product between molten boric oxide and potassium cyanide under atmospheric pressure. Thereafter, many methods for its synthesis were reported. h-BN and r-BN are formed under ambient pressure. c-BN is synthesized from h-BN under high pressure at high temperature while w-BN is prepared from h-BN under high pressure at room temperature [1]. Each BN layer consists of stacks of hexagonal plate-like units of boron and nitrogen atoms linked by SP{sup 2} hybridized orbits and held together mainly by Van der Waals force (Fig 1(b)). The hexagonal polymorph has two-layered repeating units: AA'AA'... that differ from those in graphite: ABAB... (Figure 1(a)). Within the layers of h-BN there is coincidence between the same phases of the hexagons, although the boron atoms and nitrogen atoms are alternatively located along the c

  6. Nutritional intake and dietary patterns in pregnancy: a longitudinal study of women with lifetime eating disorders

    National Research Council Canada - National Science Library

    Micali, Nadia; Northstone, Kate; Emmett, Pauline; Naumann, Ulrike; Treasure, Janet L

    2012-01-01

    ...) were compared with women who reported lifetime (ever) ED: (anorexia nervosa (AN, n 151), bulimia nervosa (BN, n 186) or both (AN+BN, n 77)). Women reported usual food consumption using a FFQ at 32 weeks of gestation...

  7. (99m)Technetium-HYNIC(tricine/TPPTS)-Aca-Bombesin(7-14) as a Targeted Imaging Agent with MicroSPECT in a PC-3 Prostate Cancer Xenograft Model

    NARCIS (Netherlands)

    Ananias, Hildo J. K.; Yu, Zilin; Dierckx, Rudi A.; van der Wiele, Christophe; Helfrich, Wijnand; Wang, Fan; Tan, Yongjun; Chen, Xiaoyuan; de Jong, Igle J.; Elsinga, Philip H.

    2011-01-01

    The peptide bombesin (BN) and derivates thereof show high binding affinity for the gastrin-releasing peptide receptor (GRPR), which is highly expressed in primary and metastasized prostate cancer. We have synthesized a new BN-based radiopharmaceutical

  8. Loneliness mediates the relationship between emotion dysregulation and bulimia nervosa/binge eating disorder psychopathology in a clinical sample.

    Science.gov (United States)

    Southward, Matthew W; Christensen, Kara A; Fettich, Karla C; Weissman, Jessica; Berona, Johnny; Chen, Eunice Y

    2014-12-01

    Emotion dysregulation has been linked to binge eating disorder (BED) and bulimia nervosa (BN) although the mechanisms by which it affects BN/BED psychopathology are unclear. This study tested loneliness as a mediator between emotion dysregulation and BN/BED psychopathology. A treatment-seeking sample of 107 women with BN or BED was assessed for loneliness (UCLA Loneliness Scale), emotion dysregulation (Difficulties in Emotion Regulation Scale), and BN/BED psychopathology (Eating Disorder Examination) before treatment. Hierarchical linear regressions and bootstrapping mediation models were run. Greater overall emotion dysregulation was associated with greater BN/BED psychopathology, mediated by loneliness (95 % CI 0.03, 0.09). Emotion dysregulation, however, did not mediate between loneliness and BN/BED psychopathology (95 % CI −0.01, 0.01). Targeting loneliness may effectively treat emotional aspects of BN/BED in women.

  9. Human Ig knockin mice to study the development and regulation of HIV-1 broadly neutralizing antibodies.

    Science.gov (United States)

    Verkoczy, Laurent; Alt, Frederick W; Tian, Ming

    2017-01-01

    A major challenge for HIV-1 vaccine research is developing a successful immunization approach for inducing broadly neutralizing antibodies (bnAbs). A key shortcoming in meeting this challenge has been the lack of animal models capable of identifying impediments limiting bnAb induction and ranking vaccine strategies for their ability to promote bnAb development. Since 2010, immunoglobulin knockin (KI) technology, involving inserting functional rearranged human variable exons into the mouse IgH and IgL loci has been used to express bnAbs in mice. This approach has allowed immune tolerance mechanisms limiting bnAb production to be elucidated and strategies to overcome such limitations to be evaluated. From these studies, along with the wealth of knowledge afforded by analyses of recombinant Ig-based bnAb structures, it became apparent that key functional features of bnAbs often are problematic for their elicitation in mice by classic vaccine paradigms, necessitating more iterative testing of new vaccine concepts. In this regard, bnAb KI models expressing deduced precursor V(D)J rearrangements of mature bnAbs or unrearranged germline V, D, J segments (that can be assembled into variable region exons that encode bnAb precursors), have been engineered to evaluate novel immunogens/regimens for effectiveness in driving bnAb responses. One promising approach emerging from such studies is the ability of sequentially administered, modified immunogens (designed to bind progressively more mature bnAb precursors) to initiate affinity maturation. Here, we review insights gained from bnAb KI studies regarding the regulation and induction of bnAbs, and discuss new Ig KI methodologies to manipulate the production and/or expression of bnAbs in vivo, to further facilitate vaccine-guided bnAb induction studies. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Imam Sahib Border Police Company Headquarters in Kunduz Province: $7.3 Million Facility Sits Largely Unused

    Science.gov (United States)

    2013-01-01

    Afghanistan Border Police Battalion (BN) Headquarters (HQ) to replace an existing sub-standard fac ility. The standard ABP BN HQ manning documents call for...current manning of the site revealed that an ABP BN HQ unit is now utilizing this as a headquarters. An ABP BN HQ has a tashkil manning of 59 personnel...The facility was built for 175 personnel. The difference in designs between an ABP battalion and a company is the amount of barrack space. The build

  11. Preparation of high-content hexagonal boron nitride composite film and characterization of atomic oxygen erosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Li, Min; Gu, Yizhuo; Wang, Shaokai, E-mail: wsk@buaa.edu.cn; Zhang, Zuoguang

    2017-04-30

    Highlights: • Hexagonal boron nitride nanosheets can be well exfoliated with the help of nanofibrillated cellulose. • A carpet-like rough surface and distortion in crystal structure of h-BN are found in both h-BN film and h-BN/epoxy film after AO exposure. • H-BN/epoxy film exhibits a higher mass loss and erosion yield, different element content changes and chemical oxidations compared with h-BN film. - Abstract: Space aircrafts circling in low earth orbit are suffered from highly reactive atomic oxygen (AO). To shield AO, a flexible thin film with 80 wt.% hexagonal boron nitride (h-BN) and h-BN/epoxy film were fabricated through vacuum filtration and adding nanofibrillated cellulose fibers. H-BN nanosheets were hydroxylated for enhancing interaction in the films. Mass loss and erosion yield at accumulated AO fluence about 3.04 × 10{sup 20} atoms/cm{sup 2} were adopted to evaluate the AO resistance properties of the films. A carpet-like rough surface, chemical oxidations and change in crystal structure of h-BN were found after AO treatment, and the degrading mechanism was proposed. The mass loss and erosion yield under AO attack were compared between h-BN film and h-BN/epoxy film, and the comparison was also done for various types of shielding AO materials. Excellent AO resistance property of h-BN film is shown, and the reasons are analyzed.

  12. Hexagonal boron nitride and graphene in-plane heterostructures: An experimentally feasible approach to charge-induced switchable CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xin; Tahini, Hassan A.; Smith, Sean C., E-mail: sean.smith@unsw.edu.au

    2016-10-20

    Hexagonal boron nitride (h-BN) has been proposed as a sorbent material for charge-induced switchable CO{sub 2} capture. However, h-BN is a wide-gap semiconductor, hindering injection of the requisite charge. Here, we employ first-principle calculations to support the proposal that in-plane h-BN/graphene (P-BN/G) heterostructures, consisting of alternating strips of h-BN and graphene, may provide an experimentally feasible material platform for voltage-induced charging of h-BN strips to realize switchable CO{sub 2} capture. Our results show that a significant amount of injected negative charges are distributed onto h-BN strips of P-BN/G, such that CO{sub 2} capture/release can be simply controlled by switching on/off the charge states of P-BN/G system. At saturation CO{sub 2} capture coverage, the negatively charged P-BN/G heterostructures achieve CO{sub 2} capture capacities up to 2.27 × 10{sup 14} cm{sup −2}, which is twice that which can be achieved on stacked h-BN/graphene (S-BN/G) nanosheets.

  13. Structural, energetic and electronic properties of intercalated boron ...

    Indian Academy of Sciences (India)

    Abstract. The effects of chirality and the intercalation of transitional metal atoms inside single walled BN nano- tubes on structural, energetic and electronic properties have been considered in this paper. The thermodynamic stability of BN nanotubes can be improved by the intercalation of cobalt or nickel. BN nanotubes can ...

  14. Hall-effect Thruster Channel Surface Properties Investigation (PREPRINT)

    Science.gov (United States)

    2011-03-03

    BN with a boric acid binder.24 Grade HP is composed primarily of BN with a calcium borate binder.25 Grade M is composed of 40% BN and 60% amorphous...aluminum, sodium, magnesium, copper, zinc , and iron, these are likely a result of anode material being sputtered onto the channel wall surfaces.37 The

  15. Biologically relevant heterodinuclear iron-manganese complexes.

    Science.gov (United States)

    Carboni, Michaël; Clémancey, Martin; Molton, Florian; Pécaut, Jacques; Lebrun, Colette; Dubois, Lionel; Blondin, Geneviève; Latour, J-M

    2012-10-01

    The heterodinuclear complexes [Fe(III)Mn(II)(L-Bn)(μ-OAc)(2)](ClO(4))(2) (1) and [Fe(II)Mn(II)(L-Bn)(μ-OAc)(2)](ClO(4)) (2) with the unsymmetrical dinucleating ligand HL-Bn {[2-bis[(2-pyridylmethyl)aminomethyl

  16. Ascorbate peroxidase gene from Brassica napus enhances salt and ...

    African Journals Online (AJOL)

    A full-length cDNA clone, BnAPX (GenBank: FJ965556.1) encoding ascorbate peroxidase and isolated from Brassica napus, was successfully introduced into Arabidopsis thaliana. Investigation into the function of BnAPX demonstrated that BnAPX transgenic plants grew better than wild type under NaCl stress, and also had ...

  17. Bandgap engineered graphene and hexagonal boron nitride for ...

    Indian Academy of Sciences (India)

    by integrating current densities over all 1D slices. In this article we are reporting DBRTD using graphene and h-BN heterostructures on h-BN substrate. Here, graphene is used for emitter, collector and well, and h-BN domains are used for tunnel barriers. The important material parame- ters used for simulation are extracted ...

  18. Poincar\\'{e} Sobolev equations in the Hyperbolic space

    OpenAIRE

    Bhakta, Mousomi; Sandeep, K.

    2011-01-01

    We study the a priori estimates,existence/nonexistence of radial sign changing solution, and the Palais-Smale characterisation of the problem $-\\De_{\\Bn}u - \\la u = |u|^{p-1}u, u\\in H^1(\\Bn)$ in the hyperbolic space $\\Bn$ where $1

  19. Structural, energetic and electronic properties of intercalated boron ...

    Indian Academy of Sciences (India)

    The effects of chirality and the intercalation of transitional metal atoms inside single walled BN nanotubes on structural, energetic and electronic properties have been considered in this paper. The thermodynamic stability of BN nanotubes can be improved by the intercalation of cobalt or nickel. BN nanotubes can behave ...

  20. Thermodynamic studies on the adsorption of Cu2+, Ni2+ and Cd2+ ...

    African Journals Online (AJOL)

    The structure of Ca-based bentonite (Ca-Bn), TEPA-Bn and TEPA-Bn after adsorbing Cu2+,Ni2+,Cd2+ had been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and simultaneous thermal gravimetric/differential thermal gravimetric (TG/DTG) analysis. The TEPA had been intercalated ...

  1. A Naturalistic Investigation of Eating Behavior in Bulimia Nervosa.

    Science.gov (United States)

    Davis, Ron; And Others

    1988-01-01

    Investigated parameters of eating behavior in subjects with bulimia nervosa (BN). BN and female comparison (FC) subjects monitored hourly over several days their food intake, mood, hunger, social circumstances, and experiences of unpleasant events. BN subjects reported more positive moods prior to consuming a meal, and more negative moods prior to…

  2. Spin transport in fully hexagonal boron nitride encapsulated graphene

    NARCIS (Netherlands)

    Gurram, M.; Omar, S.; Zihlmann, S.; Makk, P.; Schoenenberger, C.; van Wees, B. J.

    2016-01-01

    We study fully hexagonal boron nitride (hBN) encapsulated graphene spin valve devices at room temperature. The device consists of a graphene channel encapsulated between two crystalline hBN flakes: thick-hBN flake as a bottom gate dielectric substrate which masks the charge impurities from SiO2/Si

  3. Common quandaries and their practical solutions in Bayesian network modeling

    Science.gov (United States)

    Bruce G. Marcot

    2017-01-01

    Use and popularity of Bayesian network (BN) modeling has greatly expanded in recent years, but many common problems remain. Here, I summarize key problems in BN model construction and interpretation,along with suggested practical solutions. Problems in BN model construction include parameterizing probability values, variable definition, complex network structures,...

  4. Antioxidant Micronutrients: Therapeutic Counter Measures for Chemical Agents

    Science.gov (United States)

    2011-03-01

    necrosis (AEN), bronchiolar exudates (BE), bronchiolar inflammatory cell infiltrates (BICI), bronchiolar epithelial necrosis (BEN), BALT necrosis (BN...Bronchiolar epithelial necrosis (BEN), BALT necrosis (BN), Tracheal exudates (TE), Tracheal inflammatory cell infiltrates (TICI), Tracheal epithelial...BICI), Bronchiolar epithelial necrosis (BEN), BALT necrosis (BN), Tracheal exudates (TE), Tracheal inflammatory cell infiltrates (TICI), Tracheal

  5. On the dual space of a weighted Bergman space on the unit ball of Cn

    Directory of Open Access Journals (Sweden)

    J. S. Choa

    1988-01-01

    Full Text Available The weighted Bergman space Aαp(Bn(0Bn of Cn forms an F-space. We find the dual space of Aαp(Bn by determining its Mackey topology.

  6. Identification and functional prediction of stress responsive AP2/ERF transcription factors in Brassica napus by genome-wide analysis.

    Science.gov (United States)

    Owji, Hajar; Hajiebrahimi, Ali; Seradj, Hassan; Hemmati, Shiva

    2017-12-01

    Using homology and domain authentication, 321 putative AP2/ERF transcription factors were identified in Brassica napus, called BnAP2/ERF TFs. BnAP2/ERF TFs were classified into five major subfamilies, including DREB, ERF, AP2, RAV, and BnSoloist. This classification is based on phylogenetic analysis, motif identification, gene structure analysis, and physiochemical characterization. These TFs were annotated based on phylogenetic relationship with Brassica rapa. BnAP2/ERF TFs were located on 19 chromosomes of B. napus. Orthologs and paralogs were identified using synteny-based methods Ks calculation within B. napus genome and between B. napus with other species such as B. rapa, Brassica oleracea, and Arabidopsis thaliana indicated that BnAP2/ERF TFs were formed through duplication events occurred before B. napus formation. Kn/Ks values were between 0 and 1, suggesting the purifying selection among BnAP2/ERF TFs. Gene ontology annotation, cis-regulatory elements and functional interaction networks suggested that BnAP2/ERF TFs participate in response to stressors, including drought, high salinity, heat and cold as well as developmental processes particularly organ specification and embryogenesis. The identified cis-regulatory elements in the upstream of BnAP2/ERF TFs were responsive to abscisic acid. Analysis of the expression data derived from Illumina Hiseq 2000 RNA sequencing revealed that BnAP2/ERF genes were highly expressed in the roots comparing to flower buds, leaves, and stems. Also, the ERF subfamily was over-expressed under salt and fungal treatments. BnERF039 and BnERF245 are candidates for salt-tolerant B. napus. BnERF253-256 and BnERF260-277 are potential cytokinin response factors. BnERF227, BnERF228, BnERF234, BnERF134, BnERF132, BnERF176, and BnERF235 were suggested for resistance against Leptosphaeria maculan and Leptosphaeria biglobosa. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Structure of the Spiral Galaxy NGC 300

    Directory of Open Access Journals (Sweden)

    Myung-Hyun Rhee

    1992-06-01

    Full Text Available In 1963, Toomre built up classes of mass models for the highly flattened galaxies which have free parameters n, an and Cn. In order to keep the universal dimension, we adopt parameters bn(Cn2 = an2n+2*bn2/(n-1! instead of Cn. Series of the normalized Toomre's mass models (G = Vmax = Rmax = 1, n =1 to 7 are derived and the normalized parameters an and bn to an(=an*rmax and bn(=bn*Vmax/rmax, we can get the generalization of Toomre's mass model.

  8. Improvement of Thermal and Electrical Conductivity of Epoxy/boron Nitride/silver Nanoparticle Composite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungyong; Lim, Soonho [Korea Institute of Science and Technology, Wanju (Korea, Republic of)

    2017-06-15

    In this study, we investigated the effect of BN (boron nitride) on the thermal and the electrical conductivity of composites. In case of epoxy/BN composites, the thermal conductivity was increased as the BN contents were increased. Epoxy/AgNP (Ag nanoparticle) nanocomposites exhibited a slight change of thermal conductivity and showed a electrical percolation threshold at 20 vol% of Ag nanoparticles. At the fixed Ag nanoparticle content below the electrical percolation threshold, increasing the amount of BN enhanced the electrical conductivity as well as thermal conductivity for the epoxy/AgNP/BN composites.

  9. A proteomic analysis of seeds from Bt-transgenic Brassica napus and hybrids with wild B. juncea.

    Science.gov (United States)

    Liu, Yongbo; Zhang, Ying-Xue; Song, Song-Quan; Li, Junsheng; Neal Stewart, C; Wei, Wei; Zhao, Yujie; Wang, Wei-Qing

    2015-10-21

    Transgene insertions might have unintended side effects on the transgenic host, both crop and hybrids with wild relatives that harbor transgenes. We employed proteomic approaches to assess protein abundance changes in seeds from Bt-transgenic oilseed rape (Brassica napus) and its hybrids with wild mustard (B. juncea). A total of 24, 15 and 34 protein spots matching to 23, 13 and 31 unique genes were identified that changed at least 1.5 fold (p transgenic (tBN) and non-transgenic (BN) oilseed rape, between hybrids of B. juncea (BJ) × tBN (BJtBN) and BJ × BN (BJBN) and between BJBN and BJ, respectively. Eight proteins had higher abundance in tBN than in BN. None of these proteins was toxic or nutritionally harmful to human health, which is not surprising since the seeds are not known to produce toxic proteins. Protein spots varying in abundance between BJtBN and BJBN seeds were the same or homologous to those in the respective parents. None of the differentially-accumulated proteins between BJtBN and BJBN were identical to those between tBN and BN. Results indicated that unintended effects resulted from transgene flow fell within the range of natural variability of hybridization and those found in the native host proteomes.

  10. Elevated Aminopeptidase P Attenuates Cerebral Arterial Responses to Bradykinin in Fawn-Hooded Hypertensive Rats.

    Directory of Open Access Journals (Sweden)

    Md Abdul Hye Khan

    Full Text Available Cerebral arterial myogenic and autoregulatory responses are impaired in Fawn Hooded hypertensive (FHH rats. Cerebral autoregulatory responses are restored in the congenic rat strain in which a segment of chromosome 1 from the Brown Norway (BN rat was transferred into the FHH genetic background (FHH.1BN. The impact of this region on cerebral arterial dilator responses remains unknown. Aminopeptidase is a gene that was transferred into the FHH genetic background to generate the FHH.1BN rats and is responsible for degradation of the vasodilator bradykinin. Thus, we hypothesized that FHH rats will have increased aminopeptidase P levels with impaired cerebral arterial responses to bradykinin compared to BN and FHH.1BN rats. We demonstrated higher cerebral arterial expression of aminopeptidase P in FHH compared to BN rats. Accordingly, we demonstrated markedly impaired cerebral arterial dilation to bradykinin in FHH compared to BN rats. Interestingly, aminopeptidase P expression was lower in FHH.1BN compared to FHH rats. Decreased aminopeptidase P levels in FHH.1BN rats were associated with increased cerebral arterial bradykinin-induced dilator responses. Aminopeptidase P inhibition by apstatin improved cerebral arterial bradykinin dilator responses in FHH rats to a level similar to FHH.1BN rats. Unlike bradykinin, cerebral arterial responses to acetylcholine were similar between FHH and FHH.1BN groups. These findings indicate decreased bradykinin bioavailability contributes to impaired cerebral arterial dilation in FHH rats. Overall, these data indicate an important role of aminopeptidase P in the impaired cerebral arterial function in FHH rat.

  11. Exceptionally large migration length of carbon and topographically-facilitated self-limiting molecular beam epitaxial growth of graphene on hexagonal boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Plaut, Annette S.; Wurstbauer, Ulrich; Wang, Sheng; Levy, Antonio L.; Fernandes dos Santos, Lara; Wang, Lei; Pfeiffer, Loren N.; Watanabe, Kenji; Taniguchi, Takashi; Dean, Cory R.; Hone, James; Pinczuk, Aron; Garcia, Jorge M.

    2017-04-01

    We demonstrate growth of single-layer graphene (SLG) on hexagonal boron nitride (h-BN) by molecular beam epitaxy (MBE), only limited in area by the finite size of the h-BN flakes. Using atomic force microscopy and micro-Raman spectroscopy, we show that for growth over a wide range of temperatures (500 °C – 1000 °C) the deposited carbon atoms spill off the edge of the h-BN flakes. We attribute this spillage to the very high mobility of the carbon atoms on the BN basal plane, consistent with van der Waals MBE. The h-BN flakes vary in size from 30 μm to 100 μm, thus demonstrating that the migration length of carbon atoms on h-BN is greater than 100 μm. When sufficient carbon is supplied to compensate for this loss, which is largely due to this fast migration of the carbon atoms to and off the edges of the h-BN flake, we find that the best growth temperature for MBE SLG on h-BN is ~950 °C. Self-limiting graphene growth appears to be facilitated by topographic h-BN surface features: We have thereby grown MBE self-limited SLG on an h-BN ridge. This opens up future avenues for precisely tailored fabrication of nano- and hetero-structures on pre-patterned h-BN surfaces for device applications.

  12. Staged induction of HIV-1 glycan–dependent broadly neutralizing antibodies

    Science.gov (United States)

    Bonsignori, Mattia; Kreider, Edward F.; Fera, Daniela; Meyerhoff, R. Ryan; Bradley, Todd; Wiehe, Kevin; Alam, S. Munir; Aussedat, Baptiste; Walkowicz, William E.; Hwang, Kwan-Ki; Saunders, Kevin O.; Zhang, Ruijun; Gladden, Morgan A.; Monroe, Anthony; Kumar, Amit; Xia, Shi-Mao; Cooper, Melissa; Louder, Mark K.; McKee, Krisha; Bailer, Robert T.; Pier, Brendan W.; Jette, Claudia A.; Kelsoe, Garnett; Williams, Wilton B.; Morris, Lynn; Kappes, John; Wagh, Kshitij; Kamanga, Gift; Cohen, Myron S.; Hraber, Peter T.; Montefiori, David C.; Trama, Ashley; Liao, Hua-Xin; Kepler, Thomas B.; Moody, M. Anthony; Gao, Feng; Danishefsky, Samuel J.; Mascola, John R.; Shaw, George M.; Hahn, Beatrice H.; Harrison, Stephen C.; Korber, Bette T.; Haynes, Barton F.

    2017-01-01

    A preventive HIV-1 vaccine should induce HIV-1–specific broadly neutralizing antibodies (bnAbs). However, bnAbs generally require high levels of somatic hypermutation (SHM) to acquire breadth, and current vaccine strategies have not been successful in inducing bnAbs. Because bnAbs directed against a glycosylated site adjacent to the third variable loop (V3) of the HIV-1 envelope protein require limited SHM, the V3-glycan epitope is an attractive vaccine target. By studying the cooperation among multiple V3-glycan B cell lineages and their coevolution with autologous virus throughout 5 years of infection, we identify key events in the ontogeny of a V3-glycan bnAb. Two autologous neutralizing antibody lineages selected for virus escape mutations and consequently allowed initiation and affinity maturation of a V3-glycan bnAb lineage. The nucleotide substitution required to initiate the bnAb lineage occurred at a low-probability site for activation-induced cytidine deaminase activity. Cooperation of B cell lineages and an improbable mutation critical for bnAb activity defined the necessary events leading to breadth in this V3-glycan bnAb lineage. These findings may, in part, explain why initiation of V3-glycan bnAbs is rare, and suggest an immunization strategy for inducing similar V3-glycan bnAbs. PMID:28298420

  13. Bulimia nervosa in overweight and normal-weight women.

    Science.gov (United States)

    Masheb, Robin; White, Marney A

    2012-02-01

    The aim of the present study was to examine overweight bulimia nervosa (BN) in a community sample of women. Volunteers (n = 1964) completed self-report questionnaires of weight, binge eating, purging, and cognitive features. Participants were classified as overweight (body mass index ≥25) or normal weight (body mass index <25). Rates of BN within the overweight and normal-weight classes did not differ (6.4% vs 7.9%). Of the 131 participants identified as BN, 64% (n = 84) were classified as overweight BN and 36% (n = 47) as normal-weight BN. The overweight BN group had a greater proportion of ethnic minorities and reported significantly less restraint than the normal-weight BN group. Otherwise, the 2 groups reported similarly, even in terms of purging and depression. In summary, rates of BN did not differ between overweight and normal-weight women. Among BN participants, the majority (two thirds) were overweight. Differences in ethnicity and restraint, but little else, were found between overweight and normal-weight BN. Findings from the present study should serve to increase awareness of the weight range and ethnic diversity of BN, and highlight the need to address weight and cultural sensitivity in the identification and treatment of eating disorders. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Pharmacogenetic interaction between dexamethasone and Cd36-deficient segment of spontaneously hypertensive rat chromosome 4 affects triacylglycerol and cholesterol distribution into lipoprotein fractions

    Directory of Open Access Journals (Sweden)

    Křen Vladimír

    2010-04-01

    Full Text Available Abstract Dexamethasone (DEX is known to induce diabetes and dyslipidemia. We have compared fasting triacylglycerol and cholesterol concentrations across 20 lipoprotein fractions and glucose tolerance in control (standard diet and DEX-treated 7-month-old males of two rat strains, Brown Norway (BN and congenic BN.SHR-(Il6-Cd36/Cub (BN.SHR4. These two inbred strains differ in a defined segment of chromosome 4, originally transferred from the spontaneously hypertensive rat (SHR including the mutant Cd36 gene, a known target of DEX. Compared to BN, the standard-diet-fed BN.SHR4 showed higher cholesterol and triacylglycerol concentrations across many lipoprotein fractions, particularly in small VLDL and LDL particles. Total cholesterol was decreased by DEX by more than 21% in BN.SHR4 contrasting with the tendency to increase in BN (strain*DEX interaction p = 0.0017. Similar pattern was observed for triacylglycerol concentrations in LDL. The LDL particle size was significantly reduced by DEX in both strains. Also, while control BN and BN.SHR4 displayed comparable glycaemic profiles during oral glucose tolerance test, we observed a markedly blunted DEX induction of glucose intolerance in BN.SHR4 compared to BN. In summary, we report a pharmacogenetic interaction between limited genomic segment with mutated Cd36 gene and dexamethasone-induced glucose intolerance and triacylglycerol and cholesterol redistribution into lipoprotein fractions.

  15. Differences and similarities between bulimia nervosa, compulsive buying and gambling disorder.

    Science.gov (United States)

    Jiménez-Murcia, Susana; Granero, Roser; Moragas, Laura; Steiger, Howard; Israel, Mimi; Aymamí, Neus; Gómez-Peña, Mónica; Sauchelli, Sarah; Agüera, Zaida; Sánchez, Isabel; Riesco, Nadine; Penelo, Eva; Menchón, José M; Fernández-Aranda, Fernando

    2015-03-01

    The objective of the study was to analyse shared commonalities and differences between bulimia nervosa (BN) and certain impulse-related disorders, namely compulsive buying (CB) and gambling disorder (GD), with respect to general psychopathology and personality traits. A total of 188 female patients [50 BN without comorbid CB (BN-CB), 49 BN with comorbid CB (BN+CB), 53 GD and 36 CB] and 50 comparison non-psychiatric women participated in the current study. All patients were diagnosed using the Diagnostic and Statistical Manual of Mental Disorders, Fourth revised edition, the Temperament and Character Inventory-Revised, and other clinical indices. A positive-growing trend was observed in psychopathology and personality traits across the four clinical groups. Comorbid BN with CB was associated with highest eating psychopathology and social anxiety. On Novelty Seeking, the CB, GD and BN+CB were similar to each other, whereas BN-CB presented a distinct profile. Moreover, the BN+CB group displayed more dysfunctional personality traits and higher general psychopathology. The clinical groups demonstrated overall higher levels of psychopathology compared with the control group. The results of this study demonstrate that disorders with impulsive traits (CB, GD, BN+CB and BN-CB) follow a linear trend in general psychopathology and specific personality traits, but differ along specific personality and psychopathological dimensions. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association.

  16. Fabrication of translucent boron nitride dispersed polycrystalline silicon nitride ceramics

    Science.gov (United States)

    Joshi, B.; Fu, Z.; Niihara, K.; Lee, S. W.

    2011-03-01

    Optical transparency was achieved at infrared region and overall translucent silicon nitride was fabricated using hot press sintering (HPS). The increase in h-BN content decreased the optical transparency. Microstructral observations shows that the optical, mechanical and tribological properties of BN dispersed polycrystalline Si3N4 ceramics were affected by the density, α:β-phase ratio and content of h-BN in sintered ceramics. The hot pressed samples were prepared from the mixture of α-Si3N4, AlN, MgO and h-BN at 1850°C. The composite contained from 0.25 to 2 mass % BN powder with sintering aids (9% AlN + 3% MgO). Maximum transmittance of 57% was achieved for 0.25 mass % BN doped Si3N4 ceramics. Fracture toughness was increased and wear volume and friction coefficient were decreased with increase in BN content.

  17. Brain responses to body image stimuli but not food are altered in women with bulimia nervosa.

    Science.gov (United States)

    Van den Eynde, Frederique; Giampietro, Vincent; Simmons, Andrew; Uher, Rudolf; Andrew, Chris M; Harvey, Philippe-Olivier; Campbell, Iain C; Schmidt, Ulrike

    2013-11-15

    Research into the neural correlates of bulimia nervosa (BN) psychopathology remains limited. In this functional magnetic resonance imaging study, 21 BN patients and 23 healthy controls (HCs) completed two paradigms: (1) processing of visual food stimuli and (2) comparing their own appearance with that of slim women. Participants also rated food craving and anxiety levels. Brain activation patterns in response to food cues did not differ between women with and without BN. However, when evaluating themselves against images of slim women, BN patients engaged the insula more and the fusiform gyrus less, compared to HCs, suggesting increased self-focus among women with BN whilst comparing themselves to a 'slim ideal'. In these BN patients, exposure to food and body image stimuli increased self-reported levels of anxiety, but not craving. Our findings suggest that women with BN differ from HCs in the way they process body image, but not in the way they process food stimuli.

  18. Boron nitride nano-structures produced by pulsed laser ablation in acetone

    Energy Technology Data Exchange (ETDEWEB)

    Nistor, L C; Epurescu, G; Dinescu, M; Dinescu, G, E-mail: leonis@infim.ro

    2010-11-15

    Different phases of boron nitride (BN) nano-structures are synthesized from an hBN ceramic target immersed in acetone, by ablation with a high power pulsed Nd: YAG laser. Transmission electron microscopy (TEM) and electron diffraction (ED) are used to identify the morphology and structure of the prepared colloidal suspensions. It is revealed that by varying solely a single experimental parameter, i.e. the laser pulse fluency, a large variety of BN nano-structures can be produced: nanotubes, very thin graphene-like foils, nano-curls and nano-particles, all with the hexagonal graphite-like hBN structure, as well as high pressure BN phases: orthorhombic explosion E-BN nano-rods, or cubic diamond-like cBN nano-particles.

  19. Magnetic tunnel junctions with monolayer hexagonal boron nitride tunnel barriers

    Energy Technology Data Exchange (ETDEWEB)

    Piquemal-Banci, M.; Galceran, R.; Bouzehouane, K.; Anane, A.; Petroff, F.; Fert, A.; Dlubak, B.; Seneor, P. [Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767 (France); Caneva, S.; Martin, M.-B.; Weatherup, R. S.; Kidambi, P. R.; Robertson, J.; Hofmann, S. [Department of Engineering, University of Cambridge, Cambridge CB21PZ (United Kingdom); Xavier, S. [Thales Research and Technology, 1 avenue Augustin Fresnel, Palaiseau 91767 (France)

    2016-03-07

    We report on the integration of atomically thin 2D insulating hexagonal boron nitride (h-BN) tunnel barriers into Co/h-BN/Fe magnetic tunnel junctions (MTJs). The h-BN monolayer is directly grown by chemical vapor deposition on Fe. The Conductive Tip Atomic Force Microscopy (CT-AFM) measurements reveal the homogeneity of the tunnel behavior of our h-BN layers. As expected for tunneling, the resistance depends exponentially on the number of h-BN layers. The h-BN monolayer properties are also characterized through integration into complete MTJ devices. A Tunnel Magnetoresistance of up to 6% is observed for a MTJ based on a single atomically thin h-BN layer.

  20. An Update on Genetic and Serotoneric Biomarker Findings in Bulimia Nervosa

    DEFF Research Database (Denmark)

    Sjögren, Magnus

    2017-01-01

    Background: Bulimia Nervosa (BN) is a serious Eating Disorder which affects 0.8-2.9% percent of the population. The etiology of BN is largely unknown and concequently there is no curative, although psychotherapy and the antidepressant fluoxetine provide symptomatic relief. Biomarkers for BN could...... support in understanding the pathophysiology of BN, and potentially in diagnosing, and monitoring of effects of treatment. This review describes genetic and serotonergic biomarkers for BN. Method: A literature search using PUBMED (20 June 2017) was done using the following search terms: 1) “Bulimia...... are summarized. Results: Heritability, twin and targeted genetic studies support a gene contribution to the risk of BN. Although there are conflicting findings, 5HTTLPR polymorphism has been found to be linked to BN, especially to the emotional symptoms of the disorder. Several biomarker studies find support...

  1. Direct growth of graphene on in situ epitaxial hexagonal boron nitride flakes by plasma-assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhongguang; Zheng, Renjing; Khanaki, Alireza; Zuo, Zheng; Liu, Jianlin, E-mail: jianlin@ece.ucr.edu [Quantum Structures Laboratory, Department of Electrical and Computer Engineering, University of California, Riverside, California 92521 (United States)

    2015-11-23

    Hexagonal boron nitride (h-BN) single-crystal domains were grown on cobalt (Co) substrates at a substrate temperature of 850–900 °C using plasma-assisted molecular beam epitaxy. Three-point star shape h-BN domains were observed by scanning electron microscopy, and confirmed by Raman and X-ray photoelectron spectroscopy. The h-BN on Co template was used for in situ growth of multilayer graphene, leading to an h-BN/graphene heterostructure. Carbon atoms preferentially nucleate on Co substrate and edges of h-BN and then grow laterally to form continuous graphene. Further introduction of carbon atoms results in layer-by-layer growth of graphene on graphene and lateral growth of graphene on h-BN until it may cover entire h-BN flakes.

  2. Bulimia nervosa and substance use disorder: similarities and differences.

    Science.gov (United States)

    Ram, A; Stein, D; Sofer, S; Kreitler, S

    2008-01-01

    The purpose of this study was to compare bulimia nervosa (BN) and substance use disorders (SUD) in cognitive-motivational terms. The cognitive orientation theory was used as a framework for testing the hypothesis that the commonality between BN and SUD consists of a similar motivational disposition for eating disorders, rather than for addiction, as was previously claimed. It was expected that BN and SUD patients would differ from controls but not from each other. The participants were 31 BN, 20 SUD, and 20 healthy controls. They were administered questionnaires for assessing anxiety, depression, addiction and the cognitive orientation for eating disorders. On most parameters BN and SUD scored higher than controls but did not differ from each other except in norm beliefs. Treatment of BN should consider the similarity of BN to SUD in the pathological tendency for eating disorders.

  3. Immune perturbations in HIV-1-infected individuals who make broadly neutralizing antibodies.

    Science.gov (United States)

    Moody, M Anthony; Pedroza-Pacheco, Isabela; Vandergrift, Nathan A; Chui, Cecilia; Lloyd, Krissey E; Parks, Robert; Soderberg, Kelly A; Ogbe, Ane T; Cohen, Myron S; Liao, Hua-Xin; Gao, Feng; McMichael, Andrew J; Montefiori, David C; Verkoczy, Laurent; Kelsoe, Garnett; Huang, Jinghe; Shea, Patrick R; Connors, Mark; Borrow, Persephone; Haynes, Barton F

    2016-07-29

    Induction of broadly neutralizing antibodies (bnAbs) is a goal of HIV-1 vaccine development. bnAbs occur in some HIV-1-infected individuals and frequently have characteristics of autoantibodies. We have studied cohorts of HIV-1-infected individuals who made bnAbs and compared them with those who did not do so, and determined immune traits associated with the ability to produce bnAbs. HIV-1-infected individuals with bnAbs had a higher frequency of blood autoantibodies, a lower frequency of regulatory CD4+ T cells, a higher frequency of circulating memory T follicular helper CD4+ cells, and a higher T regulatory cell level of programmed cell death-1 expression compared with HIV-1-infected individuals without bnAbs. Thus, induction of HIV-1 bnAbs may require vaccination regimens that transiently mimic immunologic perturbations in HIV-1-infected individuals. Copyright © 2016, American Association for the Advancement of Science.

  4. Members of the germin-like protein family in Brassica napus are candidates for the initiation of an oxidative burst that impedes pathogenesis of Sclerotinia sclerotiorum

    Science.gov (United States)

    Cai, Daguang

    2012-01-01

    Germin-like proteins (GLPs) are defined by their sequence homology to germins from barley and are present ubiquitously in plants. Analyses of corresponding genes have revealed diverse functions of GLPs in plant development and biotic and abiotic stresses. This study describes the identification of a family of 14 germin-like genes from Brassica napus (BnGLP) designated BnGLP1–BnGLP14 and investigated potential functions of BnGLPs in plant defense against the necrotrophic fungus Sclerotinia sclerotiorum. Sequence alignment and phylogenetic analyses classify the 14 BnGLPs into four groups, which were clearly distinguished from known germin oxalic acid oxidases. Transcriptional responses of the BnGLP genes to S. sclerotiorum infection was determined by comparing cultivars of susceptible B. napus ‘Falcon’ and partially resistant B. napus ‘Zhongshuang 9’. Of the 14 BnGLP genes tested, BnGLP3 was transcriptionally upregulated in both B. napus cultivars at 6h after S. sclerotiorum infection, while upregulation of BnGLP12 was restricted to resistant B. napus ‘Zhongshuang 9’. Biochemical analysis of five representative BnGLP members identified a H2O2-generating superoxide dismutase activity only for higher molecular weight complexes of BnGLP3 and BnGLP12. By analogy, H2O2 formation at infected leaf sites increased after 6h, with even higher H2O2 production in B. napus ‘Zhongshuang 9’ compared with B. napus ‘Falcon’. Conversely, exogenous application of H2O2 significantly reduced the susceptibility of B. napus ‘Falcon’. These data suggest that early induction of BnGLP3 and BnGLP12 participates in an oxidative burst that may play a pivotal role in defence of B. napus against S. sclerotiorum. PMID:22888126

  5. Synthesis and structural studies of amido, hydrazido and imido zirconium(IV) complexes incorporating a diamido/diamine cyclam-based ligand.

    Science.gov (United States)

    Munhá, Rui F; Veiros, Luis F; Duarte, M Teresa; Fryzuk, Michael D; Martins, Ana M

    2009-09-28

    The preparation, characterisation and structural analysis of a series of zirconium(IV) complexes that incorporate the diamido/diamine macrocyclic ligand Bn2Cyclam (Bn2Cyclam = 1,8-dibenzyl-1,4,8,11-tetraazacyclotetradecane) are described. The reaction of one or two equivalents of the appropriate LiNHR reagents with [(Bn2Cyclam)ZrCl2] give the corresponding amido-chloride [(Bn2Cyclam)ZrCl(NHR)] (R = tBu, (2,6-iPr)Ph) or bis(amido) [(Bn2Cyclam)Zr(NHR)2] (R = iPr, tBu, (2,6-Me)Ph) complexes, respectively. Treatment of [(Bn2Cyclam)ZrCl(NH(2,6-iPr)Ph)] with one equiv. of MgClMe gives the base-free, monomeric imido complex [(Bn2Cyclam)Zr(N(2,6-iPr)Ph)]. The reaction of the tBu analog with MgClMe generates a dimeric bridging imido species [{(Bn2Cyclam)Zr}2(mu-NR)2], which can also be obtained by thermal decomposition of [(Bn2Cyclam)Zr(NHtBu)2] in toluene. The bis(hydrazido) complex [(Bn2Cyclam)Zr(NHNPh2)2] was obtained by reaction of [(Bn2Cyclam)ZrCl2] and two equiv. of LiNHNPh2. A hydrazido-chloride compound [(Bn2Cyclam)ZrCl(N(Ph)NBu(Ph))] was generated in a one-pot reaction between [(Bn2Cyclam)ZrCl2], LiBu and azobenzene. DFT calculations on [(Bn2Cyclam)ZrXY] complexes indicate that the coordination geometry adopted by these species is dictated by the steric bulk of the ligands X and Y, varying between six-coordinate prismatic and four-coordinate tetrahedral.

  6. Edgewood Arsenal: An Installation Environmental Impact Assessment

    Science.gov (United States)

    1975-07-01

    bush Common 64. Hamnamelis virginiana Witch hazel Uncommon ඉ. Vaccinium atrococcum Black highbush blueberry Abunday,t 66. Vacciniun corymbosum ...Common highbush blueberry Abundant 67. Vaccinium vacillans Early low blueberry Common 68. Vaccinium stamineum Deerberry Uncommon 69. Mitchella repens

  7. Estimating the current and future costs of Type 1 and Type 2 diabetes in the UK, including direct health costs and indirect societal and productivity costs.

    Science.gov (United States)

    Hex, N; Bartlett, C; Wright, D; Taylor, M; Varley, D

    2012-07-01

    To estimate the current and future economic burdens of Type 1 and Type 2 diabetes in the UK. A top-down approach was used to estimate costs for 2010/2011 from aggregated data sets and literature. Prevalence and population data were used to project costs for 2035/2036. Direct health costs were estimated from data on diagnosis, lifestyle interventions, ongoing treatment and management, and complications. Indirect costs were estimated from data on mortality, sickness, presenteeism (potential loss of productivity among people who remain in work) and informal care. Diabetes cost approximately £ 23.7bn in the UK in 2010/2011: £ 9.8bn in direct costs (£1bn for Type 1 diabetes and £ 8.8bn for Type 2 diabetes) and £ 13.9bn in indirect costs (£ 0.9bn and £ 13bn). In real terms, the 2035/2036 cost is estimated at £ 39.8bn: £ 16.9bn in direct costs (£ 1.8bn for Type 1 diabetes and £ 15.1bn for Type 2 diabetes) and £ 22.9bn in indirect costs (£ 2.4bn and £ 20.5bn). Sensitivity analysis applied to the direct costs produced a range of costs: between £ 7.9bn and £ 11.7bn in 2010/2011 and between £ 13.8bn and £20bn in 2035/2036. Diabetes currently accounts for approximately 10% of the total health resource expenditure and is projected to account for around 17% in 2035/2036. Type 1 and Type 2 diabetes are prominent diseases in the UK and are a significant economic burden. Data differentiating between the costs of Type 1 and Type 2 diabetes are sparse. Complications related to the diseases account for a substantial proportion of the direct health costs. As prevalence increases, the cost of treating complications will grow if current care regimes are maintained. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

  8. Shame and guilt as shared vulnerability factors: Shame, but not guilt, prospectively predicts both social anxiety and bulimic symptoms.

    Science.gov (United States)

    Levinson, Cheri A; Byrne, Meghan; Rodebaugh, Thomas L

    2016-08-01

    Social anxiety disorder (SAD) and bulimia nervosa (BN) are highly comorbid. However, little is known about the shared vulnerability factors that prospectively predict both SA and BN symptoms. Two potential factors that have not yet been tested are shame and guilt. In the current study we tested if shame and guilt were shared vulnerability factors for SA and BN symptoms. Women (N=300) completed measures of SA symptoms, BN symptoms, state shame and guilt, and trait negative affect at two time points, two months apart. Utilizing structural equation modeling we tested a cross-sectional and prospective model of SA and BN vulnerability. We found that shame prospectively predicted both SA and BN symptoms. We did not find that guilt prospectively predicted SA or BN symptoms. However, higher levels of both BN and SA symptoms predicted increased guilt over time. We found support for shame as a shared prospective vulnerability factor between BN and SA symptoms. Interventions that focus on decreasing shame could potentially alleviate symptoms of BN and SA in one protocol. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Toxicity evaluation of boron nitride nanospheres and water-soluble boron nitride in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Ning; Wang, Hui; Tang, Chengchun; Lei, Shijun; Shen, Wanqing; Wang, Cong; Wang, Guobin; Wang, Zheng; Wang, Lin

    2017-01-01

    Boron nitride (BN) nanomaterials have been increasingly explored for potential biological applications. However, their toxicity remains poorly understood. Using Caenorhabditis elegans as a whole-animal model for toxicity analysis of two representative types of BN nanomaterials - BN nanospheres (BNNSs) and highly water-soluble BN nanomaterial (named BN-800-2) - we found that BNNSs overall toxicity was less than soluble BN-800-2 with irregular shapes. The concentration thresholds for BNNSs and BN-800-2 were 100 µg·mL-1 and 10 µg·mL-1, respectively. Above this concentration, both delayed growth, decreased life span, reduced progeny, retarded locomotion behavior, and changed the expression of phenotype-related genes to various extents. BNNSs and BN-800-2 increased oxidative stress levels in C. elegans by promoting reactive oxygen species production. Our results further showed that oxidative stress response and MAPK signaling-related genes, such as GAS1, SOD2, SOD3, MEK1, and PMK1, might be key factors for reactive oxygen species production and toxic responses to BNNSs and BN-800-2 exposure. Together, our results suggest that when concentrations are lower than 10 µg·mL-1, BNNSs are more biocompatible than BN-800-2 and are potentially biocompatible material.

  10. Direct growth of hexagonal boron nitride/graphene heterostructures on cobalt foil substrates by plasma-assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhongguang; Khanaki, Alireza; Tian, Hao; Zheng, Renjing; Suja, Mohammad; Liu, Jianlin, E-mail: jianlin@ece.ucr.edu [Quantum Structures Laboratory, Department of Electrical and Computer Engineering, University of California, Riverside, California 92521 (United States); Zheng, Jian-Guo [Irvine Materials Research Institute, University of California, Irvine, California 92697-2800 (United States)

    2016-07-25

    Graphene/hexagonal boron nitride (G/h-BN) heterostructures have attracted a great deal of attention because of their exceptional properties and wide variety of potential applications in nanoelectronics. However, direct growth of large-area, high-quality, and stacked structures in a controllable and scalable way remains challenging. In this work, we demonstrate the synthesis of h-BN/graphene (h-BN/G) heterostructures on cobalt (Co) foil by sequential deposition of graphene and h-BN layers using plasma-assisted molecular beam epitaxy. It is found that the coverage of h-BN layers can be readily controlled on the epitaxial graphene by growth time. Large-area, uniform-quality, and multi-layer h-BN films on thin graphite layers were achieved. Based on an h-BN (5–6 nm)/G (26–27 nm) heterostructure, capacitor devices with Co(foil)/G/h-BN/Co(contact) configuration were fabricated to evaluate the dielectric properties of h-BN. The measured breakdown electric field showed a high value of ∼2.5–3.2 MV/cm. Both I-V and C-V characteristics indicate that the epitaxial h-BN film has good insulating characteristics.

  11. Understanding the Relation between Anorexia Nervosa and Bulimia Nervosa in a Swedish National Twin Sample

    Science.gov (United States)

    Bulik, Cynthia M; Thornton, Laura; Root, Tammy L.; Pisetsky, Emily M.; Lichtenstein, Paul; Pedersen, Nancy L.

    2010-01-01

    Background We present a bivariate twin analysis of anorexia nervosa (AN) and bulimia nervosa (BN) to determine the extent to which shared genetic and environmental factors contribute to liability to these disorders. Method Focusing on females from the Swedish Twin study of Adults: Genes and Environment (STAGE) (N=7000), we calculated heritability estimates for narrow and broad AN and BN and estimated their genetic correlation. Results In the full model, the heritability estimate for narrow AN was (a2 = .57; 95% CI: .00, .81) and for narrow BN (a2 = .62; 95% CI: .08, .70) with the remaining variance accounted for by unique environmental factors. Shared environmental factors estimates were (c2 = .00; 95% CI: .00, .67) for AN and (c2 = .00; 95% CI: .00, .40) for BN. Moderate additive genetic (.46) and unique environmental (.42) correlations between AN and BN were observed. Heritability estimates for broad AN were lower (a2 = .29; 95% CI: .04, .43) than for narrow AN, but estimates for broad BN were similar to narrow BN. The genetic correlation for broad AN and BN was .79 and the unique environmental correlation was .44. Conclusions We highlight the contribution of additive genetic factors to both narrow and broad AN and BN and demonstrate a moderate overlap of both genetic and unique environmental factors that influence the two conditions. Common concurrent and sequential comorbidity of AN and BN can in part be accounted for by shared genetic and environmental influences on liability although independent factors also operative. PMID:19828139

  12. Identification and characterization of lactic acid bacteria and yeasts of PDO Tuscan bread sourdough by culture dependent and independent methods.

    Science.gov (United States)

    Palla, Michela; Cristani, Caterina; Giovannetti, Manuela; Agnolucci, Monica

    2017-06-05

    Sourdough fermentation has been increasingly used worldwide, in accordance with the demand of consumers for tasty, natural and healthy food. The high diversity of lactic acid bacteria (LAB) and yeast species, detected in sourdoughs all over the world, may affect nutritional, organoleptic and technological traits of leavened baked goods. A wide regional variety of traditional sourdough breads, over 200 types, has been recorded in Italy, including special types selected as worthy of either Protected Geographical Indication (PGI) or Protected Designation of Origin (PDO), whose sourdough microbiota has been functionally and molecularly characterized. As, due to the very recent designation, the microbiota of Tuscan bread sourdough has not been investigated so far, the aim of the present work was to isolate and characterize the species composition of LAB and yeasts of PDO Tuscan bread sourdough by culture-independent and dependent methods. A total of 130 yeasts from WLN medium and 193 LAB from both mMRS and SDB media were isolated and maintained to constitute the germplasm bank of PDO Tuscan bread. Ninety six LAB from mMRS medium and 68 yeasts from WLN medium were randomly selected and molecularly identified by ARDRA (Amplified Ribosomal DNA Restriction Analysis) and PCR-RFLP analysis of the ITS region, respectively, and sequencing. The yeast identity was confirmed by 26S D1/D2 sequencing. All bacterial isolates showed 99% identity with Lactobacillus sanfranciscensis, 65 yeast isolates were identified as Candida milleri, and 3 as Saccharomyces cerevisiae. Molecular characterization of PDO Tuscan bread sourdough by PCR-DGGE confirmed such data. The distinctive tripartite species association, detected as the microbiota characterizing the sourdough used to produce PDO Tuscan bread, encompassed a large number of L. sanfranciscensis and C. milleri strains, along with a few of S. cerevisiae. The relative composition and specific physiological characteristics of such microbiota

  13. Triggering the atomic layers control of hexagonal boron nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yangxi [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Zhang, Changrui, E-mail: crzhang12@gmail.com [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Li, Bin [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Jiang, Da; Ding, Guqiao; Wang, Haomin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Xie, Xiaoming, E-mail: xmxie@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China)

    2014-09-15

    Highlights: • Thickness of h-BN films can be controlled from double atomic layers to over ten atomic layers by adjusting the CVD parameters, quite different from the reported thickness control of up to tens of nanometers. (The interlayer distance of h-BN is 0.333 nm.) • Growth mechanisms of h-BN are discussed, especially for bilayer h-BN films. • Both epitaxial growth and diffusion-segregation process are involved in the synthesis of bilayer h-BN films. - Abstract: In this work, we report the successful synthesis of large scale hexagonal boron nitride films with controllable atomic layers. The films are grown on thin nickel foils via ambient pressure chemical vapor deposition with borazine as the precursor. The atomic layers of h-BN films can be controlled in a narrow range by adjusting growth time and the cooling rates. Transmission electron microscope results shows the h-BN films exhibit high uniformity and good crystalline. X-ray photoelectron spectroscopy shows the B/N elemental ratio is about 1.01. The h-BN films exhibit a pronounced deep ultraviolet absorption at 203.0 nm with a large optical band gap of 6.02 ± 0.03 eV. The results suggest potential applications of h-BN films in deep ultraviolet and dielectric materials. Growth mechanisms of h-BN films with thickness control are discussed, especially when the synthesized h-BN films after a higher cooling rate show an in-plane rotation angle between bilayers. Both epitaxial growth and diffusion-segregation process are involved in the synthesis of bilayer h-BN films.

  14. Assessment of Gravel Operation Damage to Prehistoric Sites and Recording the Santa Fe Trail within the John Martin Reservoir Project Area, Bent County, Colorado and Evaluation of Old Las Animas (5BN176), a Late Nineteenth Century Town on the Arkansas River, Bent County, Colorado.

    Science.gov (United States)

    1987-06-01

    toothbrush fragment, 0. "__’S 2 q " , .-- , "-"-" " "% "" J""" 2" . W °’- " . .- ) ’ ’ %...’ ’’% -’ .’..’ ilm . ’ 61 Figure 4.14 Profile of the North Wall... hotels , about 20 places of business, and others opened daily. Several houses are built of adobe and several of stone, both of which are cheap and easily...washer and ironer, barber shop, hotels , Peoples and Merchants, lumber yards, blacksmith shops, gunsmith, restaurants, millinery and

  15. Functional characterization of Tet-AMPA [tetrazolyl-2-amino-3-(3-hydroxy-5-methyl- 4-isoxazolyl)propionic acid] analogues at ionotropic glutamate receptors GluR1-GluR4. The molecular basis for the functional selectivity profile of 2-Bn-Tet-AMPA

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Christesen, Thomas; Bølcho, Ulrik

    2007-01-01

    Four 2-substituted Tet-AMPA [Tet = tetrazolyl, AMPA = 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid] analogues were characterized functionally at the homomeric AMPA receptors GluR1i, GluR2Qi, GluR3i, and GluR4i in a Fluo-4/Ca2+ assay. Whereas 2-Et-Tet-AMPA, 2-Pr-Tet-AMPA, and 2-iPr-Te...

  16. A path for synthesis of boron-nitride nanostructures in volume of arc plasma.

    Science.gov (United States)

    Han, Longtao; Krstić, Predrag

    2017-02-17

    We find a possible channel for direct nanosynthesis of boron-nitride (BN) nanostructures, including growth of BN nanotubes from a mixture of BN diatomic molecules by quantum-classical molecular dynamics simulations. No catalyst or boron nanoparticle is needed for this synthesis, however the conditions for the synthesis of each of the nanostructures, such as temperature and flux of the BN feedstock are identified and are compatible with the conditions in an electric arc at high pressure. We also find that BN nanostructures can be synthetized by feeding a boron nanoparticle by BN diatomic molecules, however if hydrogen rich molecules like NH3 or HBNH are used as a feedstock, two-dimensional nanoflake stable structures are formed.

  17. Atomistic modeling of interfacial interaction between polyvinyl chloride and polypropylene with Boron-Nitride monolayer sheet: A density functional theory study

    Science.gov (United States)

    Hamed Mashhadzadeh, A.; Fereidoon, A.; Ghorbanzadeh Ahangari, M.

    2017-11-01

    In present work, we performed Density Functional Theory calculation (DFT) to prepare polypropylene (PP) and polyvinyl chloride (PVC) nanocomposite. For mentioned purpose, we chose Boron-Nitride graphene (BN-graphene) sheet as nano reinforcement. Next, we calculated adsorbed energy between these two polymeric matrixes with BN-monolayer sheet. Our DFT results demonstrated that interaction energy between PP/BN-graphene and PVC/BN-graphene are equal, approximately, because in mentioned two nanocomposite systems, polymer matrix approached to nano reinforcement from hydrogen atom in optimized structure. Then, the adsorbed energy and equilibrium distance between mentioned polymeric matrixes and BN-graphene sheet in nanocomposite with increasing the number of polymer monomers onto surface of BN-graphene were calculated. Finally, we modeled van der Waals interfacial interaction between polymer matrixes and nano reinforcement with linear classical spring by using lennard-jones parameters.

  18. Catalytic transparency of hexagonal boron nitride on copper for chemical vapor deposition growth of large-area and high-quality graphene.

    Science.gov (United States)

    Wang, Min; Kim, Minwoo; Odkhuu, Dorj; Lee, Joohyun; Jang, Won-Jun; Kahng, Se-Jong; Park, Noejung; Ruoff, Rodney S; Song, Young Jae; Lee, Sungjoo

    2014-06-24

    Graphene transferred onto h-BN has recently become a focus of research because of its excellent compatibility with large-area device applications. The requirements of scalability and clean fabrication, however, have not yet been satisfactorily addressed. The successful synthesis of graphene/h-BN on a Cu foil and DFT calculations for this system are reported, which demonstrate that a thin h-BN film on Cu foil is an excellent template for the growth of large-area and high-quality graphene. Such material can be grown on thin h-BN films that are less than 3 nm thick, as confirmed by optical microscopy and Raman spectroscopy. We have evaluated the catalytic growth mechanism and the limits on the CVD growth of high-quality and large-area graphene on h-BN film/Cu by performing Kelvin probe force microscopy and DFT calculations for various thicknesses of h-BN.

  19. Anatomical characteristics of the cerebral surface in bulimia nervosa.

    Science.gov (United States)

    Marsh, Rachel; Stefan, Mihaela; Bansal, Ravi; Hao, Xuejun; Walsh, B Timothy; Peterson, Bradley S

    2015-04-01

    The aim of this study was to examine morphometric features of the cerebral surface in adolescent and adult female subjects with bulimia nervosa (BN). Anatomical magnetic resonance images were acquired from 34 adolescent and adult female subjects with BN and 34 healthy age-matched control subjects. We compared the groups in the morphological characteristics of their cerebral surfaces while controlling for age and illness duration. Significant reductions of local volumes on the brain surface were detected in frontal and temporoparietal areas in the BN compared with control participants. Reductions in inferior frontal regions correlated inversely with symptom severity, age, and Stroop interference scores in the BN group. These findings suggest that local volumes of inferior frontal regions are smaller in individuals with BN compared with healthy individuals. These reductions along the cerebral surface might contribute to functional deficits in self-regulation and to the persistence of these deficits over development in BN. © 2014 Society of Biological Psychiatry.

  20. Bulimia nervosa symptoms in the multimodal treatment study of children with ADHD.

    Science.gov (United States)

    Mikami, Amori Yee; Hinshaw, Stephen P; Arnold, L Eugene; Hoza, Betsy; Hechtman, Lily; Newcorn, Jeffrey H; Abikoff, Howard B

    2010-04-01

    We investigated body image dissatisfaction and bingeing/purging characteristics of bulimia nervosa (BN) in the ongoing prospective follow-up of the Multimodal Treatment Study of Children with attention-deficit/hyperactivity disorder (ADHD). Participants were 337 boys and 95 girls with ADHD and 211 boys and 53 girls forming a local normative comparison group (LNCG), reassessed in midadolescence (mean age, 16.4), 8 years after original recruitment. Youth with childhood ADHD showed more BN symptoms in midadolescence than did LNCG youth, and girls demonstrated more BN symptoms than did boys, with effect sizes between small and medium. Childhood impulsivity, as opposed to hyperactivity or inattention, best predicted adolescent BN symptoms, particularly for girls. Among youth with ADHD, treatment received during the follow-up period was not associated with BN pathology. Both boys and girls with ADHD may be at risk for BN symptoms in adolescence because of the impulsivity central to both disorders.

  1. Nano boron nitride flatland.

    Science.gov (United States)

    Pakdel, Amir; Bando, Yoshio; Golberg, Dmitri

    2014-02-07

    Recent years have witnessed many breakthroughs in research on two-dimensional (2D) nanomaterials, among which is hexagonal boron nitride (h-BN), a layered material with a regular network of BN hexagons. This review provides an insight into the marvellous nano BN flatland, beginning with a concise introduction to BN and its low-dimensional nanostructures, followed by an overview of the past and current state of research on 2D BN nanostructures. A comprehensive review of the structural characteristics and synthetic routes of BN monolayers, multilayers, nanomeshes, nanowaves, nanoflakes, nanosheets and nanoribbons is presented. In addition, electronic, optical, thermal, mechanical, magnetic, piezoelectric, catalytic, ecological, biological and wetting properties, applications and research perspectives for these novel 2D nanomaterials are discussed.

  2. GAO report and EDF cost revisions reignite debate on Hinkley Point C

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, David [NucNet, The Independent Global Nuclear News Agency, Brussels (Belgium)

    2017-10-15

    The announcement by French state-controlled utility EDF that it has added pound 1.5 bn (Euro 1.7 bn, $ 1.9 bn) to its estimated costs for two new reactors at Hinkley Point C, has led to questions about whether the government should rethink the project, with some politicians calling for it to be abandoned. EDF's announcement came less than two weeks after a report from the Government Accountability Office (GAO) said the government's deal for the two EPR units, now estimated to be costing pound 19.6 bn (Euro 22.3 bn, $ 25.5 bn), has locked consumers into a risky and expensive project with uncertain strategic and economic benefits. The UK's Energy Technologies Institute (ETI), in a report prepared before the EDF announcement, had already said the requirement to improve the predictability and affordability of new nuclear power plants has never been stronger.

  3. Bombesin receptor-mediated imaging and cytotoxicity: review and current status

    Science.gov (United States)

    Sancho, Veronica; Di Florio, Alessia; Moody, Terry W.; Jensen, Robert T.

    2010-01-01

    The three mammalian bombesin (Bn) receptors (gastrin-releasing peptide [GRP] receptor, neuromedin B [NMB] receptor, BRS-3) are one of the classes of G protein-coupled receptors that are most frequently over-express/ectopically expressed by common, important malignancies. Because of the clinical success of somatostatin receptor-mediated imaging and cytotoxicity with neuroendocrine tumors, there is now increasing interest in pursuing a similar approach with Bn receptors. In the last few years then have been more than 200 studies in this area. In the present paper, the in vitro and in vivo results, as well as results of human studies from many of these studies are reviewed and the current state of Bn receptor-mediated imaging or cytotoxicity is discussed. Both Bn receptor-mediated imaging studies as well as Bn receptor-mediated tumoral cytotoxic studies using radioactive and non-radioactive Bn-based ligands are covered. PMID:21034419

  4. Precipitation growth of graphene under exfoliated hexagonal boron nitride to form heterostructures on cobalt substrate by molecular beam epitaxy

    Science.gov (United States)

    Zheng, Renjing; Khanaki, Alireza; Tian, Hao; He, Yanwei; Cui, Yongtao; Xu, Zhongguang; Liu, Jianlin

    2017-07-01

    Research on graphene/hexagonal boron nitride (h-BN) heterostructures has attracted much attention for band engineering and device performance optimization of graphene. However, the growth of graphene/h-BN heterostructure is still challenging, which usually requires high growth temperature and long growth duration. In this paper, we demonstrate graphene/h-BN heterostructures by growing graphene onto the substrates which consist of exfoliated h-BN flakes on Co thin films using molecular beam epitaxy. The heterostructure samples grown at different temperatures and growth times were characterized by Raman, optical microscopy, atomic force microscopy, microwave impedance microscopy, and scanning tunneling microscopy. It is found that the graphene/h-BN heterostructures were formed by the formation of graphene underneath rather than on top of the h-BN flakes. The growth mechanism is discussed.

  5. State of logistics - a five-year review

    CSIR Research Space (South Africa)

    Ittmann, HW

    2009-07-01

    Full Text Available .5% to the world’s production, carries 0.5% of the logistics costs and contributes nearly 2.5% of world road ton-kilometers. The country requires 4.4 times the ton-kilometers for each dollar of production moved compared to the rest of the world and engineered a... FOR THE FUTURE 6 OF 20 Table 1: Adjustments to Previous Survey Results Due To Model Improvements Year 2003 2004 2005 2006 Inventory carrying cost (2007 model) R26bn R27bn R28bn R30b Restated Inventory carrying cost (2008 model) R26bn R29bn R33bn R38b...

  6. One-Dimensional Nanostructures for Neutron Detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yong [North Carolina State Univ., Raleigh, NC (United States); Eapen, Jacob [North Carolina State Univ., Raleigh, NC (United States); Hawari, Ayman [North Carolina State Univ., Raleigh, NC (United States)

    2015-05-04

    This report consists of four parts in addition to a publication/presentation list. Part I is on electronic structure simulations on boron nitride (BN) and BCxN nanotubes using density function theory (DFT), Part II is on fabrication and characterization of nanowire sensors, Part III is on irradiation response of BN nanotubes using molecular dynamics (MD) simulations, and Part IV is on the in-situ transmission electron microscopy (TEM) study of irradiation response of BN nanotubes.

  7. The effect of deposition parameters on the boron nitride films grown on Si(100) by PLD with nanosecond pulses

    Science.gov (United States)

    Luculescu, C. R.; Sato, Shunichi; Fenic, Constantin G.

    2004-10-01

    The effects of several deposition parameters on the quality of deposited boron nitride (BN) films by pulsed laser deposition (PLD) with short laser pulses are studied. The laser fluence, nitrogen background pressure, Si(100) substrate temperature and laser wavelength were varied in order to find the maximum content of the cubic phase in our BN films. We found that laser fluence and wavelength are affecting strongly the structure of BN films while background pressure and substrate temperature are affecting slightly the film morphology.

  8. Genome-Wide Survey of Flavonoid Biosynthesis Genes and Gene Expression Analysis between Black- and Yellow-Seeded Brassica napus

    Science.gov (United States)

    Qu, Cunmin; Zhao, Huiyan; Fu, Fuyou; Wang, Zhen; Zhang, Kai; Zhou, Yan; Wang, Xin; Wang, Rui; Xu, Xinfu; Tang, Zhanglin; Lu, Kun; Li, Jia-Na

    2016-01-01

    Flavonoids, the compounds that impart color to fruits, flowers, and seeds, are the most widespread secondary metabolites in plants. However, a systematic analysis of these loci has not been performed in Brassicaceae. In this study, we isolated 649 nucleotide sequences related to flavonoid biosynthesis, i.e., the Transparent Testa (TT) genes, and their associated amino acid sequences in 17 Brassicaceae species, grouped into Arabidopsis or Brassicaceae subgroups. Moreover, 36 copies of 21 genes of the flavonoid biosynthesis pathway were identified in Arabidopsis thaliana, 53 were identified in Brassica rapa, 50 in Brassica oleracea, and 95 in B. napus, followed the genomic distribution, collinearity analysis and genes triplication of them among Brassicaceae species. The results showed that the extensive gene loss, whole genome triplication, and diploidization that occurred after divergence from the common ancestor. Using qRT-PCR methods, we analyzed the expression of 18 flavonoid biosynthesis genes in 6 yellow- and black-seeded B. napus inbred lines with different genetic background, found that 12 of which were preferentially expressed during seed development, whereas the remaining genes were expressed in all B. napus tissues examined. Moreover, 14 of these genes showed significant differences in expression level during seed development, and all but four of these (i.e., BnTT5, BnTT7, BnTT10, and BnTTG1) had similar expression patterns among the yellow- and black-seeded B. napus. Results showed that the structural genes (BnTT3, BnTT18, and BnBAN), regulatory genes (BnTTG2 and BnTT16) and three encoding transfer proteins (BnTT12, BnTT19, and BnAHA10) might play an crucial roles in the formation of different seed coat colors in B. napus. These data will be helpful for illustrating the molecular mechanisms of flavonoid biosynthesis in Brassicaceae species. PMID:27999578

  9. Comparison in decision-making between bulimia nervosa, anorexia nervosa, and healthy women: influence of mood status and pathological eating concerns

    OpenAIRE

    Matsumoto, Junko; Hirano, Yoshiyuki; Numata, Noriko; Matzuzawa, Daisuke; Murano, Shunichi; Yokote, Koutaro; Iyo, Masaomi; Shimizu, Eiji; Nakazato, Michiko

    2015-01-01

    Background Decision-making is reported to be impaired in anorexia nervosa (AN) and bulimia nervosa (BN), but the influence of mood status, pathophysiological eating, and weight concerns on the performance of decision-making ability between AN and BN is still unclear. The aims of this study were to investigate differential impairments in the decision-making process between AN, BN, and healthy controls (HC), and secondly, to explore the role of mood status, such as anxiety, depression, patholog...

  10. Novel route to cubic boron nitride dendritic nanostructures under electron beam irradiation

    CERN Document Server

    Yin, L W; Liu, Y X; Xu, B; Qi, Y X; Sui, J L

    2003-01-01

    The growth of c-BN dendritic nanostructures (see Figure) has been investigated in situ using a combination of characterization techniques. It is concluded that the electron beam irradiation induced nucleation and growth of the nanostructures in vacuum is closely related to the nanoarches at the edge of the h-BN starting material. A solid-state mechanism different from the traditional one for BN nanostructure growth from the gas phase is proposed. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  11. How should DSM-V classify eating disorder not otherwise specified (EDNOS) presentations in women with lifetime anorexia or bulimia nervosa?

    Science.gov (United States)

    Eddy, K T; Swanson, S A; Crosby, R D; Franko, D L; Engel, S; Herzog, D B

    2010-10-01

    Anorexia nervosa (AN) and bulimia nervosa (BN) are marked by longitudinal symptom fluctuations. DSM-IV-TR does not address how to classify eating disorder (ED) presentations in individuals who no longer meet full criteria for these disorders. To consider this issue, we examined subthreshold presentations in women with initial diagnoses of AN and BN. A total of 246 women with AN or BN were followed for a median of 9 years; weekly symptom data were collected at frequent intervals using the Longitudinal Interval Follow-up Evaluation of Eating Disorders (LIFE-EAT-II). Outcomes were ED presentations that were subthreshold for 3 months, including those narrowly missing full criteria for AN or BN, along with binge eating disorder (BED) and purging disorder. During follow-up, most women (77.6%) experienced a subthreshold presentation. Subthreshold presentation was related to intake diagnosis (Wald chi2=8.065, df=2, p=0.018). Individuals with AN most often developed subthreshold presentations resembling AN; those with BN were more likely to develop subthreshold BN. Purging disorder was experienced by half of those with BN and one-quarter of those with AN binge/purge type (ANBP); BED occurred in 20% with BN. Transition from AN or BN to most subthreshold types was associated with improved psychosocial functioning (p<0.001). Subthreshold presentations in women with lifetime AN and BN were common, resembled the initial diagnosis, and were associated with modest improvements in psychosocial functioning. For most with lifetime AN and BN, subthreshold presentations seem to represent part of the course of illness and to fit within the original AN or BN diagnosis.

  12. Bulimia nervosa in adolescents: prevalence and treatment challenges

    OpenAIRE

    Hail, Lisa; Le Grange, Daniel

    2018-01-01

    Lisa Hail, Daniel Le Grange Department of Psychiatry, University of California, San Francisco, CA, USA Abstract: Bulimia nervosa (BN) is a serious psychiatric illness that typically develops during adolescence or young adulthood, rendering adolescents a target for early intervention. Despite the increasing research devoted to the treatment of youth with anorexia nervosa (AN) and adults with BN, there remains a dearth of evidence for treating younger individuals with BN. To date, ther...

  13. Kognitiv-behaviorale Psychotherapie bei Jugendlichen mit Essstörungen

    OpenAIRE

    Ruhl, Uwe; Jacobi, Corinna

    2005-01-01

    Anorexia nervosa (AN), Bulimia nervosa (BN) und Binge Eating Störungen (BED) werden unter dem Begriff Essstörungen zusammengefasst. Insbesondere die AN stellt im Jugendalter aufgrund des typischen Beginns in diesem Altersbereich eine häufige Erkrankung mit häufig ungünstigen Verlauf (Steinhausen 2002) dar. Die psychischen, sozialen und körperlichen Folgen sind gravierend. Die Therapieforschung zeigt, dass die kognitiv-behaviorale Behandlung (CBT) bei BN, BN und BED im Erwachsenena...

  14. Dimensions of emotion dysregulation in bulimia nervosa

    OpenAIRE

    Lavender, Jason M.; Wonderlich, Stephen A.; Peterson, Carol B.; Crosby, Ross D.; Engel, Scott G.; Mitchell, James E.; Crow, Scott J.; Smith, Tracey L.; Klein, Marjorie H.; Goldschmidt, Andrea B; Berg, Kelly C.

    2014-01-01

    The goal of this study was to examine associations between dimensions of emotion dysregulation and eating disorder (ED) symptoms in bulimia nervosa (BN). This investigation used baseline data from a BN treatment study that included 80 adults (90% women) with full or subthreshold BN. Participants completed the Difficulties in Emotion Regulation Scale (DERS) and the Eating Disorders Examination (EDE) interview. The EDE global score was significantly correlated with the DERS total score, as well...

  15. Genome-wide survey of flavonoid biosynthesis genes and gene expression analysis between black- and yellow-seeded Brassica napus

    Directory of Open Access Journals (Sweden)

    Cunmin Qu

    2016-12-01

    Full Text Available Flavonoids, the compounds that impart color to fruits, flowers, and seeds, are the most widespread secondary metabolites in plants. However, a systematic analysis of these loci has not been performed in Brassicaceae. In this study, we isolated 649 nucleotide sequences related to flavonoid biosynthesis, i.e., the Transparent Testa (TT genes, and their associated amino acid sequences in 17 Brassicaceae species, grouped into Arabidopsis or Brassicaceae subgroups. Moreover, 36 copies of 21 genes of the flavonoid biosynthesis pathway were identified in A. thaliana, 53 were identified in B. rapa, 50 in B. oleracea, and 95 in B. napus, followed the genomic distribution, collinearity analysis and genes triplication of them among Brassicaceae species. The results showed that the extensive gene loss, whole genome triplication, and diploidization that occurred after divergence from the common ancestor. Using qRT-PCR methods, we analyzed the expression of eighteen flavonoid biosynthesis genes in 6 yellow- and black-seeded B. napus inbred lines with different genetic background, found that 12 of which were preferentially expressed during seed development, whereas the remaining genes were expressed in all B. napus tissues examined. Moreover, fourteen of these genes showed significant differences in expression level during seed development, and all but four of these (i.e., BnTT5, BnTT7, BnTT10, and BnTTG1 had similar expression patterns among the yellow- and black-seeded B. napus. Results showed that the structural genes (BnTT3, BnTT18 and BnBAN, regulatory genes (BnTTG2 and BnTT16 and three encoding transfer proteins (BnTT12, BnTT19, and BnAHA10 might play an crucial roles in the formation of different seed coat colors in B. napus. These data will be helpful for illustrating the molecular mechanisms of flavonoid biosynthesis in Brassicaceae species.

  16. Transforming the South African transport sector across the value chain for development impact

    CSIR Research Space (South Africa)

    Vivekanandan, M

    2017-10-01

    Full Text Available into the National Treasury • Mandate – Covers entire African continent; focus on Southern Africa • Financially sound – R84bn Assets, R32bn Equity, R3Bn+ sustainable profits • Externally rated – DBSA foreign currency rating is Baa3 (Moody’s) – similar...-return trade-off and longer tenors Access to concessionary financing Continue core long-term infrastructure lending activities Strategic Ambition: Catalyse R100Bn annually in infrastructure by 2019-20, while maintaining financial sustainability...

  17. Enhanced Seed Oil Production in Canola by Conditional Expression of Brassica napus LEAFY COTYLEDON1 and LEC1-LIKE in Developing Seeds1[W][OA

    Science.gov (United States)

    Tan, Helin; Yang, Xiaohui; Zhang, Fengxia; Zheng, Xiu; Qu, Cunmin; Mu, Jinye; Fu, Fuyou; Li, Jiana; Guan, Rongzhan; Zhang, Hongsheng; Wang, Guodong; Zuo, Jianru

    2011-01-01

    The seed oil content in oilseed crops is a major selection trait to breeders. In Arabidopsis (Arabidopsis thaliana), LEAFY COTYLEDON1 (LEC1) and LEC1-LIKE (L1L) are key regulators of fatty acid biosynthesis. Overexpression of AtLEC1 and its orthologs in canola (Brassica napus), BnLEC1 and BnL1L, causes an increased fatty acid level in transgenic Arabidopsis plants, which, however, also show severe developmental abnormalities. Here, we use truncated napin A promoters, which retain the seed-specific expression pattern but with a reduced expression level, to drive the expression of BnLEC1 and BnL1L in transgenic canola. Conditional expression of BnLEC1 and BnL1L increases the seed oil content by 2% to 20% and has no detrimental effects on major agronomic traits. In the transgenic canola, expression of a subset of genes involved in fatty acid biosynthesis and glycolysis is up-regulated in developing seeds. Moreover, the BnLEC1 transgene enhances the expression of several genes involved in Suc synthesis and transport in developing seeds and the silique wall. Consistently, the accumulation of Suc and Fru is increased in developing seeds of the transgenic rapeseed, suggesting the increased carbon flux to fatty acid biosynthesis. These results demonstrate that BnLEC1 and BnL1L are reliable targets for genetic improvement of rapeseed in seed oil production. PMID:21562329

  18. Preparation and Characterization of Ni Spines Grown on the Surface of Cubic Boron Nitride Grains by Electroplating Method

    Directory of Open Access Journals (Sweden)

    Yanghai Gui

    2016-03-01

    Full Text Available Cubic boron nitride (cBN is widely applied in cutting and grinding tools. cBN grains plated by pure Ni and Ni/SiC composite were produced under the same conditions from an additive-free nickel Watts type bath. The processed electroplating products were characterized by the techniques of scanning electron microscopy (SEM, X-ray diffraction (XRD and thermoanalysis (TG-DTA. Due to the presence of SiC particles, there are some additional nodules on the surface of Ni/SiC plated cBN compared with the pure Ni plated cBN. The unique morphology of Ni/SiC plated cBN should attain greater retention force in resin bond. Moreover, the coating weight of cBN grains could be controlled by regulating the plating time. cBN grains with 60% coating weight possess the optimum grinding performance due to their roughest and spiniest surface. In addition, Ni spines plated cBN grains show good thermal stability when temperature is lower than 464 °C. Therefore, the plated cBN grains are more stable and suitable for making resin bond abrasive tools below 225 °C. Finally, the formation mechanism of electroplating products is also discussed.

  19. Synthesis and applications of two-dimensional hexagonal boron nitride in electronics manufacturing

    Science.gov (United States)

    Bao, Jie; Jeppson, Kjell; Edwards, Michael; Fu, Yifeng; Ye, Lilei; Lu, Xiuzhen; Liu, Johan

    2016-01-01

    In similarity to graphene, two-dimensional (2D) hexagonal boron nitride (hBN) has some remarkable properties, such as mechanical robustness and high thermal conductivity. In addition, hBN has superb chemical stability and it is electrically insulating. 2D hBN has been considered a promising material for many applications in electronics, including 2D hBN based substrates, gate dielectrics for graphene transistors and interconnects, and electronic packaging insulators. This paper reviews the synthesis, transfer and fabrication of 2D hBN films, hBN based composites and hBN-based van der Waals heterostructures. In particular, this review focuses on applications in manufacturing electronic devices where the insulating and thermal properties of hBN can potentially be exploited. 2D hBN and related composite systems are emerging as new and industrially important materials, which could address many challenges in future complex electronics devices and systems. [Figure not available: see fulltext.

  20. Fluoxetine augments ventilatory CO2 sensitivity in Brown Norway but not Sprague Dawley rats

    Science.gov (United States)

    Hodges, Matthew R.; Echert, Ashley E.; Puissant, Madeleine M.; Mouradian, Gary C.

    2013-01-01

    The Brown Norway (BN; BN/NHsdMcwi) rat exhibits a deficit in ventilatory CO2 sensitivity and a modest serotonin (5-HT) deficiency. Here, we tested the hypothesis that the selective serotonin reuptake inhibitor fluoxetine would augment CO2 sensitivity in BN but not Sprague Dawley (SD) rats. Ventilation during room air or 7 % CO2 exposure was measured before, during and after 3 weeks of daily injections of saline or fluoxetine (10 mg/kg/day) in adult male BN and SD rats. Fluoxetine had minimal effects on room air breathing in BN and SD rats (p>0.05), although tidal volume (VT) was reduced in BN rats (pfluoxetine on CO2 sensitivity in SD rats, but fluoxetine increased minute ventilation, breathing frequency and VT during hypercapnia in BN rats (pfluoxetine. Brain levels of biogenic amines were largely unaffected, but 5-HIAA and the ratio of 5-HIAA/5-HT were reduced (pfluoxetine increases ventilatory CO2 sensitivity in BN but not SD rats, further suggesting altered 5-HT system function may contribute to the inherently low CO2 sensitivity in the BN rat. PMID:23454023

  1. A Review on the Preparation of Borazine-derived Boron Nitride Nanoparticles and Nanopolyhedrons by Spray-pyrolysis and Annealing Process

    Directory of Open Access Journals (Sweden)

    Vincent Salles

    2016-01-01

    Full Text Available Boron nitride (BN nanostructures (= nanoBN are struc‐ tural analogues of carbon nanostructures but display different materials chemistry and physics, leading to a wide variety of structural, thermal, electronic, and optical applications. Proper synthesis routes and advanced structural design are among the great challenges for preparing nanoBN with such properties. This review provides an insight into the preparation and characteriza‐ tion of zero dimensional (0D nanoBN including nanopar‐ ticles and nanopolyhedrons from borazine, an economically competitive and attractive (from a technical point of view molecule, beginning with a concise intro‐ duction to hexagonal BN, followed by an overview on the past and current state of research on nanoparticles. Thus, a review of the spray-pyrolysis of borazine to form BN nanoparticles is firstly presented. The use of BN nanopar‐ ticles as precursors of BN nanopolyhedrons is then de‐ tailed. Applications and research perspectives for these 0D nanoBN are discussed in the conclusion.

  2. Central coherence in adolescents with bulimia nervosa spectrum eating disorders.

    Science.gov (United States)

    Darcy, Alison M; Fitzpatrick, Kathleen Kara; Manasse, Stephanie M; Datta, Nandini; Klabunde, Megan; Colborn, Danielle; Aspen, Vandana; Stiles-Shields, Colleen; Labuschagne, Zandre; Le Grange, Daniel; Lock, James

    2015-07-01

    Weak central coherence-a tendency to process details at the expense of the gestalt-has been observed among adults with bulimia nervosa (BN) and is a potential candidate endophenotype for eating disorders (EDs). However, as BN behaviors typically onset during adolescence it is important to assess central coherence in this younger age group to determine whether the findings in adults are likely a result of BN or present earlier in the evolution of the disorder. This study examines whether the detail-oriented and fragmented cognitive inefficiency observed among adults with BN is observable among adolescents with shorter illness duration, relative to healthy controls. The Rey-Osterrieth Complex Figure Test (RCFT) was administered to a total of 47 adolescents with DSM5 BN, 42 with purging disorder (PD), and 25 healthy controls (HC). Performance on this measure was compared across the three groups. Those with BN and PD demonstrated significantly worse accuracy scores compared to controls in the copy and delayed recall condition with a moderate effect size. These findings were exacerbated when symptoms of BN increased. Poorer accuracy scores reflect a fragmented and piecemeal strategy that interferes with visual-spatial integration in BN spectrum disorders. This cognitive inefficiency likely contributes to broad difficulties in executive functioning in this population especially in the context of worsening bulimic symptoms. The findings of this study support the hypothesis that poor global integration may constitute a cognitive endophenotype for BN. © 2014 Wiley Periodicals, Inc.

  3. A pilot study examining diagnostic differences among exercise and weight suppression in bulimia nervosa and binge eating disorder.

    Science.gov (United States)

    Cook, Brian J; Steffen, Kristine J; Mitchell, James E; Otto, Maxwell; Crosby, Ross D; Cao, Li; Wonderlich, Stephen A; Crow, Scott; Hill, Laura; Le Grange, Daniel; Powers, Pauline

    2015-05-01

    The objective of this study was to investigate diagnostic differences in weight suppression (e.g., the difference between one's current body weight and highest non-pregnancy adult body weight) and exercise among Bulimia Nervosa (BN) and Binge Eating Disorder (BED). Because exercise may be a key contributor to weight suppression in BN, we were interested in examining the potential moderating effect of exercise on weight suppression in BN or BED. Participants with BN (n = 774) and BED (n = 285) completed self-report surveys of weight history, exercise and eating disorder symptoms. Generalised linear model analyses were used to examine the associations among diagnosis, exercise frequency and their interaction on weight suppression. Exercise frequency and BN/BED diagnosis were both associated with weight suppression. Additionally, exercise frequency moderated the relationship between diagnosis and weight suppression. Specifically, weight suppression was higher in BN than in BED among those with low exercise frequency but comparable in BN and BED among those with high exercise frequency. Our results suggest that exercise frequency may contribute to different weight suppression outcomes among BN and BED. This may inform clinical implications of exercise in these disorders. Specifically, much understanding of the differences among exercise frequency and the compensatory use of exercise in BN and BED is needed. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

  4. Enhanced seed oil production in canola by conditional expression of Brassica napus LEAFY COTYLEDON1 and LEC1-LIKE in developing seeds.

    Science.gov (United States)

    Tan, Helin; Yang, Xiaohui; Zhang, Fengxia; Zheng, Xiu; Qu, Cunmin; Mu, Jinye; Fu, Fuyou; Li, Jiana; Guan, Rongzhan; Zhang, Hongsheng; Wang, Guodong; Zuo, Jianru

    2011-07-01

    The seed oil content in oilseed crops is a major selection trait to breeders. In Arabidopsis (Arabidopsis thaliana), LEAFY COTYLEDON1 (LEC1) and LEC1-LIKE (L1L) are key regulators of fatty acid biosynthesis. Overexpression of AtLEC1 and its orthologs in canola (Brassica napus), BnLEC1 and BnL1L, causes an increased fatty acid level in transgenic Arabidopsis plants, which, however, also show severe developmental abnormalities. Here, we use truncated napin A promoters, which retain the seed-specific expression pattern but with a reduced expression level, to drive the expression of BnLEC1 and BnL1L in transgenic canola. Conditional expression of BnLEC1 and BnL1L increases the seed oil content by 2% to 20% and has no detrimental effects on major agronomic traits. In the transgenic canola, expression of a subset of genes involved in fatty acid biosynthesis and glycolysis is up-regulated in developing seeds. Moreover, the BnLEC1 transgene enhances the expression of several genes involved in Suc synthesis and transport in developing seeds and the silique wall. Consistently, the accumulation of Suc and Fru is increased in developing seeds of the transgenic rapeseed, suggesting the increased carbon flux to fatty acid biosynthesis. These results demonstrate that BnLEC1 and BnL1L are reliable targets for genetic improvement of rapeseed in seed oil production.

  5. Functional analysis and tissue-differential expression of four FAD2 genes in amphidiploid Brassica napus derived from Brassica rapa and Brassica oleracea.

    Science.gov (United States)

    Lee, Kyeong-Ryeol; In Sohn, Soo; Jung, Jin Hee; Kim, Sun Hee; Roh, Kyung Hee; Kim, Jong-Bum; Suh, Mi Chung; Kim, Hyun Uk

    2013-12-01

    Fatty acid desaturase 2 (FAD2), which resides in the endoplasmic reticulum (ER), plays a crucial role in producing linoleic acid (18:2) through catalyzing the desaturation of oleic acid (18:1) by double bond formation at the delta 12 position. FAD2 catalyzes the first step needed for the production of polyunsaturated fatty acids found in the glycerolipids of cell membranes and the triacylglycerols in seeds. In this study, four FAD2 genes from amphidiploid Brassica napus genome were isolated by PCR amplification, with their enzymatic functions predicted by sequence analysis of the cDNAs. Fatty acid analysis of budding yeast transformed with each of the FAD2 genes showed that whereas BnFAD2-1, BnFAD2-2, and BnFAD2-4 are functional enzymes, and BnFAD2-3 is nonfunctional. The four FAD2 genes of B. napus originated from synthetic hybridization of its diploid progenitors Brassica rapa and Brassica oleracea, each of which has two FAD2 genes identical to those of B. napus. The BnFAD2-3 gene of B. napus, a nonfunctional pseudogene mutated by multiple nucleotide deletions and insertions, was inherited from B. rapa. All BnFAD2 isozymes except BnFAD2-3 localized to the ER. Nonfunctional BnFAD2-3 localized to the nucleus and chloroplasts. Four BnFAD2 genes can be classified on the basis of their expression patterns. © 2013.

  6. Nickel cobaltite nanosheets strongly anchored on boron and nitrogen co-doped graphene for high-performance asymmetric supercapacitors

    Science.gov (United States)

    Jiao, Xinyan; Xia, Xifeng; Liu, Peng; Lei, Wu; Ouyang, Yu; Hao, Qingli

    2017-08-01

    Strongly coupled boron and nitrogen co-doped graphene (BN-G) hybrids with nickel cobaltite (NiCo2O4) nanosheets (NCO/BN-G) were fabricated by a facile soft-chemical method for asymmetric supercapacitors with high-performance. The strong interaction between BN-G and NiCo2O4 nanosheets are explored by various techniques. The effect of heteroatom doping on electrochemical properties of the hybrids is systematically investigated. The strong synergistic effect between NiCo2O4 and BN-G leads to a specific capacitance of 106.5 mA h g-1 at the current density of 0.5 A g-1 and capacitance retention of 96.8% after 10 000 cycles at 5 A g-1, much better than those of the pure NiCo2O4 and its hybrid with N-doped graphene. Moreover, an asymmetric supercapacitor device, assembled with NCO/BN-G and activated carbon (NCO/BN-G//AC), exhibits a maximum energy density of 45.6 Wh kg-1 and an excellent cycling stability. The improved electrochemical performance of the NCO/BN-G hybrid is attributed to the good conductivity of BN-G and the synergistic effect between NiCo2O4 nanosheets and BN-G combined together through a plane-to-plane contact mode.

  7. Optical properties of bulk semiconductors and graphene/boron nitride: the Bethe-Salpeter equation with derivative discontinuity-corrected density functional energies

    DEFF Research Database (Denmark)

    Yan, Jun; Jacobsen, Karsten W.; Thygesen, Kristian S.

    2012-01-01

    through the BSE using the statically screened interaction evaluated in the random phase approximation. For a representative set of semiconductors and insulators we find excellent agreement with experiments for the dielectric functions, onset of absorption, and lowest excitonic features. For the two......-dimensional systems of graphene and hexagonal boron-nitride (h-BN) we find good agreement with previous many-body calculations. For the graphene/h-BN interface we find that the fundamental and optical gaps of the h-BN layer are reduced by 2.0 and 0.7 eV, respectively, compared to freestanding h-BN. This reduction...

  8. Optical and Electrical Properties of III-Nitrides and Related Materials

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hongxing [Texas Tech Univ., Lubbock, TX (United States); Lin, Jingyu [Texas Tech Univ., Lubbock, TX (United States)

    2016-01-22

    Among the members of the III-nitride material system, boron-nitride (BN) is the least studied and understood. Its extraordinary physical properties, such as ultra-high chemical stability, thermal conductivity, electrical resistivity, band gap (Eg ~ 6 eV), and optical absorption near the band gap make hexagonal BN (h-BN) the material of choice for emerging applications such as deep ultraviolet (DUV) optoelectronic devices. Moreover, h-BN has a close lattice match to graphene and is the most suitable substrate and dielectric/separation layer for graphene electronics and optoelectronics. Similar to graphene, low dimensional h-BN is expected to possess rich new physics. Other potential applications include super-capacitors and electron emitters. However, our knowledge concerning the semiconducting properties of h-BN is very scarce. The project aims to extend our studies to the “newest” family member of the III-nitride material system, h-BN, and to address issues that have not yet been explored but are expected to profoundly influence our understanding on its fundamental properties and device applications. During the supporting period, we have improved the growth processes of h-BN epilayers by metal organic chemical vapor deposition (MOCVD), investigated the fundamental material properties, and identified several unique features of h-BN as well as critical issues that remain to be addressed.

  9. Elevated BSC-1 and ROMK expression in Dahl salt-sensitive rat kidneys.

    Science.gov (United States)

    Hoagland, Kimberly M; Flasch, Averia K; Dahly-Vernon, Annette J; dos Santos, Elisabete Alcantara; Knepper, Mark A; Roman, Richard J

    2004-04-01

    This study compared the expression of enzymes and transport and channel proteins involved in the regulation of sodium reabsorption in the kidney of Dahl salt-sensitive (DS) and salt-resistant Brown-Norway (BN) and consomic rats (SS.BN13), in which chromosome 13 from the BN rat has been introgressed into the DS genetic background. The expression of the Na+/K+/2Cl- (BSC-1) cotransporter, Na+/H+ exchanger (NHE3), and Na+-K+-ATPase proteins were similar in the renal cortex of DS, BN, and SS.BN13 rats fed either a low-salt (0.1% NaCl) or a high-salt (8% NaCl) diet. The expression of the BSC-1 and the renal outer medullary K+ channel (ROMK) were higher, whereas the expression of the cytochrome P4504A proteins responsible for the formation of 20-hydroxyeicosatetraenoic (20-HETE) was lower in the outer medulla of the kidney of DS than in BN or SS.BN13 rats fed either a low-salt or a high-salt diet. In addition, the renal formation and excretion of 20-HETE was lower in DS than in BN and SS.BN13 rats. These results suggest that overexpression of ROMK and BSC-1 in the thick ascending limb combined with a deficiency in renal formation of 20-HETE may predispose Dahl S rats fed a high-salt diet to Na+ retention and hypertension.

  10. Elastocaloric effect on the piezoelectric potential of boron nitride nanotubes

    Science.gov (United States)

    Zhang, Jin

    2017-10-01

    In this paper, molecular dynamics (MD) simulations and analytical calculations are performed to study the influence of the elastocaloric effect (ECE) on the piezoelectric potential of hexagonal boron nitride (BN) nanotubes. To take into account the ECE in the simulations and calculations, the adiabatic condition is required. To reach this goal, the heat transfer between the BN nanotubes and their environment is excluded in the present study. In MD simulations, we find a large ECE in BN nanotubes, which will make the temperature of the BN nanotubes greatly change after external loads are applied on them. Moreover, the piezoelectric and dielectric properties of BN nanotubes calculated from MD simulations are found to be strongly dependent on the temperature. The temperature-dependent piezoelectric and dielectric properties together with the ECE are thus considered in the analytical calculations of the piezoelectric potential of BN nanotubes. The obtained analytical results reveal that the large ECE in BN nanotubes will make the piezoelectric potential of BN nanotubes strongly depend on the loading path of external loads. Specifically, stretching a BN nanotube is found to be more efficient than compressing the nanotube to generate the piezoelectric potential. These results are expected to significantly expand the knowledge of the electromechanical behaviours of piezoelectric nanomaterials and provide important guidelines for the optimum design of piezotronics nanodevices.

  11. Evaluation of yeast diversity during wine fermentations with direct inoculation and pied de cuve method at an industrial scale.

    Science.gov (United States)

    Li, Erhu; Liu, Chuanhe; Liu, Yanlin

    2012-07-01

    The diversity and composition of yeast populations may greatly impact wine quality. This study investigated the yeast microbiota in two different types of wine fermentations: direct inoculation of a commercial starter versus pied de cuve method at an industrial scale. The pied de cuve fermentation entailed growth of the commercial inoculum used in the direct inoculation fermentation for further inoculation of additional fermentations. Yeast isolates were collected from different stages of wine fermentation and identified to the species level using Wallersterin Laboratory nutrient (WLN) agar followed by analysis of the 26S rDNA D1/D2 domain. Genetic characteristics of the Saccharomyces cerevisiae strains were assessed by a rapid PCR-based method, relying on the amplification of interdelta sequences. A total of 412 yeast colonies were obtained from all fermentations and eight different WL morphotypes were observed. Non-Saccharomyces yeast mainly appeared in the grape must and at the early stages of wine fermentation. S. cerevisiae was the dominant yeast species using both fermentation techniques. Seven distinguishing interdelta sequence patterns were found among S. cerevisiae strains, and the inoculated commercial starter, AWRI 796, dominated all stages in both direct inoculation and pied de cuve fermentations. This study revealed that S. cerevisiae was the dominant species and an inoculated starter could dominate fermentations with the pied de cuve method under controlled conditions.

  12. Investigating of yeast species in wine fermentation using terminal restriction fragment length polymorphism method.

    Science.gov (United States)

    Sun, Yue; Liu, Yanlin

    2014-04-01

    The objective of this study was to examine the potential of terminal restriction fragment length polymorphism (T-RFLP) in monitoring yeast communities during wine fermentation and to reveal new information on yeast community of Chinese enology. Firstly, terminal restriction fragment (TRF) lengths database was constructed using 32 pure yeast species. Ten of these species were firstly documented. The species except for Candida vini, Issatchenkia orientalis/Candida krusei, Saccharomyces bayanus, Saccharomyces pastorianus, Saccharomyces cerevisiae, Saccharomyces kudriarzevii and Zygosaccharomyces bisporus could be distinguished by the T-RFLP targeting 5.8S-ITS rDNA. Moreover, the yeast communities in spontaneous fermentation of Chardonnay and Riesling were identified by T-RFLP and traditional methods, including colony morphology on Wallerstein Nutrient (WLN) medium and 5.8S-ITS-RFLP analysis. The result showed that T-RFLP profiles of the yeast community correlated well with that of the results identified by the traditional methods. The TRFs with the highest intensity and present in all the samples corresponded to Saccharomyces sp. Other species detected by both approaches were Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia minuta var. minuta, Saccharomycodes ludwigii/Torulaspora delbrueckii and Candida zemplinina. This study revealed that T-RFLP technique is a rapid and useful tool for monitoring the composition of yeast species during wine fermentation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. An exploratory assessment of theory of mind and psychological impairment in patients with bulimia nervosa.

    Science.gov (United States)

    Laghi, Fiorenzo; Cotugno, Armando; Cecere, Francesco; Sirolli, Arianna; Palazzoni, David; Bosco, Francesca M

    2014-11-01

    This study aimed to investigate psychosocial functioning and different dimensions of theory of mind (ToM) in people with bulimia nervosa (BN) and Eating Disorder Not Otherwise Specified-BN type (EDNOS-BN). Psychosocial functioning and ToM were assessed in a sample of young adult females, 16 BN and 16 EDNOS-BN outpatients and 16 healthy controls (HCs). They were assessed using the Eating Disorder Inventory-Symptom Checklist-2 (EDI-2 SC) for evaluating psychological traits associated with eating disorders; the Symptom Checklist-90-Revised (SCL-90-R) for evaluating psychopathological status; and the Theory of Mind Assessment Scale (Th.o.m.a.s.), a semi-structured interview aimed at assessing a person's different dimensions of ToM. The BN and EDNOS-BN groups exhibited worse performance than the control group on all dimensions of the SCL-90-R, and on all dimensions of the EDI-2 SC. The only difference for perfectionism was that BN obtained higher scores than EDNOS-BN group. Our results also revealed an impairment of third-person and second-order ToM in patients with bulimia (BN and EDNOS-BN) with respect to control subjects. These preliminary data have important implications for future empirical work, in that they provide valuable information regarding the importance of investigating the various facets of ToM ability separately, in order to provide a more detailed profile of ToM functioning in the clinical samples. © 2013 The British Psychological Society.

  14. The prevalence and correlates of binge eating disorder in the WHO World Mental Health Surveys

    Science.gov (United States)

    Kessler, Ronald C.; Berglund, Patricia A.; Chiu, Wai Tat; Deitz, Anne C.; Hudson, James I.; Shahly, Victoria; Aguilar-Gaxiola, Sergio; Alonso, Jordi; Angermeyer, Matthias C.; Benjet, Corina; Bruffaerts, Ronny; de Girolamo, Giovanni; de Graaf, Ron; Haro, Josep Maria; Kovess-Masfety, Viviane; O’Neill, Siobhan; Posada-Villa, Jose; Sasu, Carmen; Scott, Kate; Viana, Maria Carmen; Xavier, Miguel

    2013-01-01

    Background Little population-based data exist outside the United States on the epidemiology of binge eating disorder (BED). Cross-national data on BED are presented and compared to bulimia nervosa (BN) based on the WHO World Mental Health Surveys. Methods Community surveys with 24,124 respondents (ages 18+) across 14 mostly upper-middle and high income countries assessed lifetime and 12-month DSM-IV mental disorders with the WHO Composite International Diagnostic Interview. Physical disorders were assessed with a chronic conditions checklist. Results Country-specific lifetime prevalence estimates are consistently (median; inter-quartile range) higher for BED (1.4%;0.8–1.9%) than BN (0.8%;0.4–1.0%). Median age-of-onset is in the late teens to early 20s for both disorders but slightly younger for BN. Persistence is slightly higher for BN (6.5 years; 2.2–15.4) than BED (4.3 years; 1.0–11.7). Lifetime risk of both disorders is elevated for women and recent cohorts. Retrospective reports suggest that comorbid anxiety, mood, and disruptive behavior disorders predict subsequent onset of BN somewhat more strongly than BED and that BN predicts subsequent comorbid psychiatric disorders somewhat more strongly than does BED. Significant comorbidities with physical conditions are due almost entirely to BN and BED predicting subsequent onset of these conditions, again with BN somewhat stronger than BED. Role impairments are similar for BN and BED. Fewer than half of lifetime BN or BED cases receive treatment. Conclusions BED represents a public health problem at least equal to BN. Low treatment rates highlight the clinical importance of questioning patients about eating problems even when not included among presenting complaints. PMID:23290497

  15. Cognitive Behavior Therapy with Body Image Exposure for Bulimia Nervosa: A Case Example

    Science.gov (United States)

    Delinsky, Sherrie S.; Wilson, G. Terence

    2010-01-01

    Cognitive behavior therapy (CBT) is an effective treatment for bulimia nervosa (BN). However, among patients with BN, symptom improvement is more pronounced for behavioral eating symptoms (i.e., bingeing and purging) than for body image disturbance, and the persistence of body image disturbance is associated with relapse. The need for more…

  16. 1 jl/yn 1TX

    Indian Academy of Sciences (India)

    Amber Valley Residential. School. K M Road Mugthihalli. Chickmagalur 577 101, India. Email: shailesh_shirali@rediffmail.com. Keywords. Normal distribution. Solution to. On a Use of Normal Distribution. Problem. For positive integers n, consider the quantities An and. Bn defined by. 1TX cos2n. - dx. 2 '. 1 jl/yn 1TX. Bn = A.

  17. Layer-structured hexagonal boron nitride carbon semiconductor alloys for deep UV photonics

    Science.gov (United States)

    Uddin, Md Rakib; Li, Jing; Lin, Jingyu; Jiang, Hongxing

    2015-03-01

    Hexagonal boron nitride carbon alloys, h - (BN)1-x(C2)x, are layer-structured semiconductor materials with a tunable bandgap energy from 0 eV (graphite) to 6.5 eV (h-BN). We report on synthesizing (BN)-rich h - (BN)1-x(C2)x semiconductor alloys using standard MOCVD growth technique on sapphire substrate. Bandgap energy variation with carbon concentration in the deep UV spectral range has been demonstrated through optical absorption measurements. Experimental results suggest that the critical carbon concentration (xc) to form the homogenous h - (BN)1-x(C2)x alloys is about 3.2% at a growth temperature of 1300 °C. It is expected that homogenous h - (BN)1-x(C2)x alloys with higher x can be achieved by increasing the growth temperature. This is a huge advantage over the InGaN alloy system in which higher growth temperatures cannot be utilized to close the miscibility gap. Together with our ability for producing high quality h-BN epilayers, h-(BN)C alloys and quantum wells open up new possibilities for realizing novel 2D optoelectronic devices with tunable physical properties. National Science Foundation.

  18. Suppression of intrinsic roughness in encapsulated graphene

    DEFF Research Database (Denmark)

    Thomsen, Joachim Dahl; Gunst, Tue; Gregersen, Søren Schou

    2017-01-01

    to the rms vibrational amplitudes of carbon atoms in bulk graphite. Our first-principles calculations of the phonon bands in graphene/hBN heterostructures show that the flexural acoustic phonon mode is localized predominantly in the hBN layer. Consequently, the flexural displacement of the atoms...

  19. Application of Bayesian networks for hazard ranking of nanomaterials to support human health risk assessment

    NARCIS (Netherlands)

    Marvin, Hans J.P.; Bouzembrak, Yamine; Janssen, Esmée M.; Zande, van der Meike; Murphy, Finbarr; Sheehan, Barry; Mullins, Martin; Bouwmeester, Hans

    2017-01-01

    In this study, a Bayesian Network (BN) was developed for the prediction of the hazard potential and biological effects with the focus on metal- and metal-oxide nanomaterials to support human health risk assessment. The developed BN captures the (inter) relationships between the exposure route, the

  20. Ascorbate peroxidase gene from Brassica napus enhances salt and ...

    African Journals Online (AJOL)

    use

    2011-12-12

    Dec 12, 2011 ... A cytosolic APX from tomato could enhance its tolerance to chilling and ... In our previous researches, B. napus APX gene. (BnAPX) was cloned and sequenced. The amino acid sequence of the BnAPX had 77% homology to thylakoidal ... cauliflower mosaic virus 35S (CaMV35S) promoter (Figure 1a). The.