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Sample records for centre dot 6h

  1. Inversion of spin levels in Ni sup 2 sup + : Zn(BF sub 4) sub 2 centre dot 6H sub 2 O at all -round compression and effect of transition coincidence

    CERN Document Server

    Krygin, I M; Nejlo, G N; Prokhorov, A D

    2001-01-01

    The study of the EPR spectrum of the Ni sup 2 sup + ion, replacing Zn sup 2 sup + in the Zn(BF sub 4) centre dot 6H sub 2 O crystals in the wide temperature range by the all-round compression in the X- and Q-ranges is carried out. The basic changes by varying temperature and pressure occur with the D parameter, characterizing the initial splitting by practically unchanged g-factor. The increase in the temperature is accompanied by the D nonlinear growth. The all-round compression linearly changes the initial splitting and leads to the change in the D-sign, signifying the spin levels inversion by 3.5 kbar. Coincidence of EPR lines, relative to different transitions, leads to the crevasse appearance in the outline of this one, that is connected with cross-relaxation inside the spin system

  2. Investigations on the local structure and the spin-Hamiltonian parameters for the tetragonal $Cu^{2+}$ centre in $ZnGeF_{6}·6H_{2}O$ crystal

    Indian Academy of Sciences (India)

    LI CHAO-YING; HUANG YING; ZHENG XUE MEI

    2016-08-01

    The spin-Hamiltonian parameters ($g$ factors $g_{||}, g{|perp}$ and hyperfine structure constants $A_{||}$, $A{|perp}$) and the local structure for the tetragonal $Cu^{2+}$ centre in trigonal $ZnGeF_{6}·6H_{2}O$ crystal are theoretically studied using the perturbation formulae of these parameters for a 3d9 ion in tetragonally elongated octahedra. In the calculations, the contributions to the spin-Hamiltonian parameters from ligand orbital and spin-orbit coupling are included on the basis of the cluster approach in view of moderate covalency of the studied systems, and the required crystal field parameters are obtained using the superposition model and the local structures of the studied $[Cu(H_{2}O)_{6}]^{2+}$ cluster. According to the calculations, the ligand octahedra around $Cu^{2+}$ suffer relative elongation$\\tau{\\sim 0.085 \\AA) along the [0 0 1] (or $C_4$) axis for the tetragonal $Cu^{2+}$ centres in $ZnGeF_{6}·6H_{2}O$ crystal, due to the Jahn--Teller effect. The calculated results show good agreement with the experimental data.

  3. Face-Centred-Cubic Artificial Opal Embedded with CdS Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    徐岭; 李明海; 张宇; 马懿; 徐骏; 黄信凡; 陈坤基

    2002-01-01

    Highly monodispersed colloidal silica spheres in sub-micrometre size with distribution standard deviation less than 5% were synthesized by a chemical method. Using the self-crystallization of the silica spheres, we successfully obtained the three-dimensional close-packed face-centred-cubic silica matrices and artificial opals. Then,a colloidal photonic crystal embedded with CdS quantum dots (QDs) was also chemically prepared by using artificial opals as a template. A reflection spectra study reveals that both artificial opals with and without CdS QDs possess (111) directional photonic bandgap features.

  4. Deuteron and triton production in Pb+Pb collisions at 158 A centre dot GeV.

    CERN Document Server

    Hansen, A G; Bøggild, H; Boissevain, J G; Conin, L; Christiansen, P; Dodd, J; Erazmus, B; Esumi, S; Fabjan, Christian Wolfgang; Ferenc, D; Fields, D E; Franz, A; Gaardhøje, J J; Hansen, A G; Hansen, O; Hardtke, D; Hecke, H V; Holzer, E B; Humanic, T J; Hummel, P; Jacak, B V; Jayanti, R; Kaimi, K; Kaneta, M; Kohama, T; Kopytine, M; Leltchouk, M; Ljubicic, A; Lörstad, B; Martin, L; Maeda, N; Malina, R; Medvedev, A; Murray, M; Ohnishi, H; Paic, G; Pandey, S U; Piuz, François; Pluta, J; Polychronakos, V; Potekhin, M V; Poulard, G; Reichhold, D M; Sakaguchi, A; Simon-Gillo, J; Schmidt-Sørensen, J; Sondheim, W E; Sugitate, T; Sullivan, J P; Sumi, Y; Willis, W J; Wolf, K L; Xu, N; Zachary, D S

    1999-01-01

    NA44 has measured the invariant cross section of deuterons and tritons at non zero p sub t in 158 A centre dot GeV lead on lead collisions at CERN SPS. Normalized transverse mass spectra and coalescence parameters versus p sub t have been calculated showing a significant transverse flow. Radius parameters have been extracted using a simple thermal coalescence model. Results from RQMD+coalescence calculations are compared to the data.

  5. Nanodiamond-based nanostructures for coupling nitrogen-vacancy centres to metal nanoparticles and semiconductor quantum dots

    Science.gov (United States)

    Gong, Jianxiao; Steinsultz, Nat; Ouyang, Min

    2016-01-01

    The ability to control the interaction between nitrogen-vacancy centres in diamond and photonic and/or broadband plasmonic nanostructures is crucial for the development of solid-state quantum devices with optimum performance. However, existing methods typically employ top-down fabrication, which restrict scalable and feasible manipulation of nitrogen-vacancy centres. Here, we develop a general bottom-up approach to fabricate an emerging class of freestanding nanodiamond-based hybrid nanostructures with external functional units of either plasmonic nanoparticles or excitonic quantum dots. Precise control of the structural parameters (including size, composition, coverage and spacing of the external functional units) is achieved, representing a pre-requisite for exploring the underlying physics. Fine tuning of the emission characteristics through structural regulation is demonstrated by performing single-particle optical studies. This study opens a rich toolbox to tailor properties of quantum emitters, which can facilitate design guidelines for devices based on nitrogen-vacancy centres that use these freestanding hybrid nanostructures as building blocks. PMID:27273426

  6. Nanodiamond-based nanostructures for coupling nitrogen-vacancy centres to metal nanoparticles and semiconductor quantum dots

    Science.gov (United States)

    Gong, Jianxiao; Steinsultz, Nat; Ouyang, Min

    2016-06-01

    The ability to control the interaction between nitrogen-vacancy centres in diamond and photonic and/or broadband plasmonic nanostructures is crucial for the development of solid-state quantum devices with optimum performance. However, existing methods typically employ top-down fabrication, which restrict scalable and feasible manipulation of nitrogen-vacancy centres. Here, we develop a general bottom-up approach to fabricate an emerging class of freestanding nanodiamond-based hybrid nanostructures with external functional units of either plasmonic nanoparticles or excitonic quantum dots. Precise control of the structural parameters (including size, composition, coverage and spacing of the external functional units) is achieved, representing a pre-requisite for exploring the underlying physics. Fine tuning of the emission characteristics through structural regulation is demonstrated by performing single-particle optical studies. This study opens a rich toolbox to tailor properties of quantum emitters, which can facilitate design guidelines for devices based on nitrogen-vacancy centres that use these freestanding hybrid nanostructures as building blocks.

  7. Nuclear magnetic relaxation in the ferrimagnetic chain compound NiCu(C{sub 7}H{sub 6}N{sub 2}O{sub 6})(H{sub 2}O){sub 3}{center_dot}2H{sub 2}O : three-magnon scattering?

    Energy Technology Data Exchange (ETDEWEB)

    Hori, Hiromitsu; Yamamoto, Shoji [Division of Physics, Hokkaido University, Sapporo 060-0810 (Japan)

    2004-12-15

    Recent proton spin-lattice relaxation-time (T{sub 1}) measurements on the ferrimagnetic chain compound NiCu(C{sub 7}H{sub 6}N{sub 2}O{sub 6})(H{sub 2}O){sub 3}{center_dot}2H{sub 2}O are explained by an elaborately modified spin-wave theory. We give strong evidence of the major contribution to 1/T{sub 1} being made by the three-magnon scattering rather than the Raman scattering.

  8. Ferroelectric TGS ((NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4) under high pressure

    CERN Document Server

    Kobayashi, Y; Furuta, H; Endo, S; Deguchi, K

    2002-01-01

    The ferroelectric transition temperature T sub c of (NH sub 2 CH sub 2 COOH) sub 3 centre dot H sub 2 SO sub 4 (TGS), which is a typical order-disorder-type ferroelectric, was determined by dielectric constant and Raman scattering measurements under high pressure. T sub c increased, passed through a maximum and then decreased slightly with increasing pressure, and then abruptly dropped at about 2.5 GPa, where a transition to a new high-pressure phase was confirmed to exist. A tentative p-T phase diagram was proposed for TGS.

  9. Activation of silicon quantum dots and coupling between the active centre and the defect state of the photonic crystal in a nanolaser

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Chen Hang-Qiong; Shu Qin; Liu Shi-Rong; Qin Chao-Jian

    2012-01-01

    A new nanolaser concept using silicon quantum dots (QDs) is proposed.The conduction band opened by the quantum confinement effect gives the pumping levels.Localized states in the gap due to some surface bonds on Si QDs can be formed for the activation of emission.An inversion of population can be generated between the localized states and the valence band in a QD fabricated by using a nanosecond pulse laser.Coupling between the active centres formed by localized states and the defect states of the two-dimensional (2D) photonic crystal can be used to select the model in the nanolaser.

  10. Optical excitation in doped quasi-one-dimensional antiferromagnet (CsMnCl3 centre dot 2H2O+Cu2+)

    International Nuclear Information System (INIS)

    In the wide range of wavelengths and temperatures, the spectra of light absorption and luminescence excitation as well as the emission decay kinetics of a quasi-one-dimensional dielectric crystal CsMnCl3 centre dot 2H2O doped with copper ions (molar concentration 0-3%) are studied. The conclusion is made of the exchange of electronic excitation energy being possible between the matrix and dopant subsystems only in the lowest excited state due to migration of excitation and their trapping by excitation traps of the copper origin. From the analysis of the shape of decay kinetics curves of the matrix luminescence of the crystal, the values of hopping (along the chains of manganese ions) and trapping rates of magnetic excitons are determined

  11. NMR investigation on isotope effect of glycinium phosphite H sub 3 NCH sub 2 COOH centre dot H sub 2 PO sub 3

    CERN Document Server

    Ishibashi, T

    2003-01-01

    The motions of the phosphite anions and glycinium cations in H sub 3 NCH sub 2 COOH centre dot H sub 2 PO sub 3 (GPI) and its deuterated analogue (DGPI) were investigated by sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P spin-lattice relaxation times T sub 1. For both GPI and DGPI, T sub 1 's of the sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P nuclei reflect the amino rotation, methylene libration and motion of the phosphite anions, respectively. Activation energies obtained from T sub 1 's of sup 1 H, sup 1 sup 3 C and sup 3 sup 1 P nuclei are 28.6(2), 26.0(4) and 26.2(4) kJ/mol for GPI and are 34.9(6), 27(1), 47(2) kJ/mol for DGPI, respectively. The deuterium substitution increases E sub a for the motion influenced by the hydrogen bonding. In all the observed motions, correlation times of DGPI are larger than those of GPI. (author)

  12. Aspects of the historical development of targetry for heavy ions of 0.05-2000 A centre dot MeV at GSI

    CERN Document Server

    Folger, H

    1999-01-01

    The progressively improved GSI accelerators provide beams of heavy ions from energies of 0.05-2000 A centre dot MeV at high particle intensities now. Therefore, a wide variety of common and new heavy-ion target techniques had to be installed and developed during the past 25 years to prepare and characterize self-supported or backed heavy-ion-targets of chemical elements and compounds from hydrogen (as polyethylene) to uranium. The thickness ranged from 2x10 sup - sup 6 to 20 g/cm sup 2 for beam spots of about 5 mm in diameter. Homogeneity, surface structure or individual shape had to be adapted to the needs of each experiment. Special setups were required for targets of poisonous materials, of highly enriched stable isotopes or those of radioactive species in minute amounts. The capability of thin-layer technologies was as well applied to prepare and measure stripper foils or various high-vacuum deposits for experimental or accelerator purposes. The development of different rotating target wheels and control ...

  13. Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

    Science.gov (United States)

    Nakra Mohajer, Soukaina; El Harouny, El Hassan; Ibral, Asmaa; El Khamkhami, Jamal; Assaid, El Mahdi

    2016-09-01

    Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

  14. A Spectroscopic Survey of Electronic Transitions of C$_6$H, $^{13}$C$_6$H, and C$_6$D

    CERN Document Server

    Bacalla, Xavier; Linnartz, Harold; Ubachs, Wim; Zhao, Dongfeng

    2016-01-01

    Electronic spectra of C$_6$H are measured in the $18\\,950-21\\,100$ cm$^{-1}$ domain using cavity ring-down spectroscopy of a supersonically expanding hydrocarbon plasma. In total, 19 (sub)bands of C$_6$H are presented, all probing the vibrational manifold of the B$^2\\Pi$ electronically excited state. The assignments are guided by electronic spectra available from matrix isolation work, isotopic substitution experiments (yielding also spectra for $^{13}$C$_6$H and C$_6$D), predictions from ab initio calculations as well as rotational fitting and vibrational contour simulations using the available ground state parameters as obtained from microwave experiments. Besides the $0_0^0$ origin band, three non-degenerate stretching vibrations along the linear backbone of the C$_6$H molecule are assigned: the $\

  15. The effect of split sleep schedules (6h-on/6h-off) on neurobehavioural performance, sleep and sleepiness.

    Science.gov (United States)

    Short, Michelle A; Centofanti, Stephanie; Hilditch, Cassie; Banks, Siobhan; Lushington, Kurt; Dorrian, Jillian

    2016-05-01

    Shorter, more frequent rosters, such as 6h-on/6h-off split shifts, may offer promise to sleep, subjective sleepiness and performance by limiting shift length and by offering opportunities for all workers to obtain some sleep across the biological night. However, there exists a paucity of studies that have examined these shifts using objective measures of sleep and performance. The present study examined neurobehavioural performance, sleepiness and sleep during 6h-on/6h-off split sleep schedules. Sixteen healthy adults (6 males, 26.13 y ± 4.46) participated in a 9-day laboratory study that included two baseline nights (BL, 10h time in bed (TIB), 2200 h-0800 h), 4 days on one of two types of 6h-on/6h-off split sleep schedules with 5h TIB during each 'off' period (6h early: TIB 0300 h-0800 h and 1500 h-20000 h, or 6-h late: TIB 0900 h-1400 h and 2100 h-0200 h), and two recovery nights (10h TIB per night, 2200 h-0800 h). Participants received 10h TIB per 24h in total across both shift schedules. A neurobehavioural test bout was completed every 2 h during wake, which included the Psychomotor Vigilance Task (PVT) and the Karolinska Sleepiness Scale (KSS). Linear mixed effects models were used to assess the effect of day (BL, shift days 1-4), schedule (6h early, 6h late) and trial (numbers 1-6) on PVT lapses (operationalised as the number of reaction times >500 ms), PVT total lapse time, PVT fastest 10% of reaction times and KSS. Analyses were also conducted examining the effect of day and schedule on sleep variables. Overall, PVT lapses and total lapse time did not differ significantly between baseline and shift days, however, peak response speeds were significantly slower on the first shift day when compared to baseline, but only for those in the 6h-late condition. Circadian variations were apparent in performance outcomes, with individuals in the 6h-late condition demonstrated significantly more and longer lapses and slower peak reaction times at the end of their

  16. Magnetic susceptibility of Co sup 2 sup + pairs in [Co sub 2 (ox)tpmc](ClO sub 4) sub 2 centre dot 3H sub 2 O cluster complex

    CERN Document Server

    Spasojevic, V; Sovilj, S P; Mrozinski, J

    2000-01-01

    Calculation of the magnetic susceptibility of Co sup 2 sup + pairs in the recently synthesized cobaltous cluster complex [Co sub 2 (ox)tpmc](ClO sub 4) sub 2 centre dot 3H sub 2 O has been conducted by the use of two different theoretical models. The calculated results were compared to the experimental data collected in a wide temperature region. Conclusions on both the magnetic properties of Co sup 2 sup + dimers and the validity of the proposed models have been drawn. In the temperature region above chi(T) maximum, the best results are obtained with the Heisenberg model that includes spin-orbit coupling and excited single-ion levels. In the low-temperature region anisotropy of the magnetic properties dominates and Ising dimer ground-state model gives a more appropriate description. Obtained g-values (g sub p sub a sub r sub a sub l sub l sub e sub l a=5.67, g sub p sub a sub r sub a sub l sub l sub e sub l b=5.73, and g sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r =1.54) con...

  17. Main: 1L6H [RPSD[Archive

    Lifescience Database Archive (English)

    Full Text Available cule: Non-Specific Lipid Transfer Protein; Chain: A; Synonym: Ltp2 Lipid Transport D.Samuel, P.-C.Lyu D.Samu... SWS:P83210,P83210|PDB; 1L6H; NMR; A=1-69.|Gramene; P83210; -.|InterPro; IPR003612; AAI.|Pfam; PF00234; Tryp..._alpha_amyl; 1.|SMART; SM00499; AAI; 1. Nmr, Minimized Average Structure Length: 69 AA, Molecular weight: 7009 Da AGCNAGQLTVCTGAI

  18. Quadra-Quantum Dots and Related Patterns of Quantum Dot Molecules: Basic Nanostructures for Quantum Dot Cellular Automata Application

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2010-10-01

    Full Text Available Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called 'Droplet Epitaxy' has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390'C with a droplet growth rate of 1ML/s. Arsenic flux (7'8'10-6Torr is then exposed for InGaAs crystallization at 200'C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or, which are preferable crystallographic directions of quantum dot alignment in general.

  19. Frustrated quantum magnetism in the 6H-perovskites

    Science.gov (United States)

    Quilliam, Jeffrey

    I will review the recent state of research on the 6H-perovskites, Ba3MA2O9, a large class of materials that can accommodate many different magnetic ions on ostensibly triangular lattices. This class of materials has given rise to several important discoveries in recent years, including quantum spin liquids, a quantum spin-orbital liquid and the first perfectly triangular spin-1/2 antiferromagnet. Many of these materials also provide an interesting interplay of magnetic, orbital and charge degrees of freedom. Others suffer from high levels of site disorder, which leads to interesting physics, at least in the case of the spin-orbital liquid candidate Ba3CuSb2O9. I will primarily discuss our recent work on the materials Ba3MSb2O9, where M = Cu, Ni and Co using the techniques of nuclear magnetic resonance (NMR), muon spin rotation (μSR) and ultrasound velocity measurements.

  20. Quadra-quantum Dots and Related Patterns of Quantum Dot Molecules:

    Directory of Open Access Journals (Sweden)

    Somsak Panyakeow

    2010-10-01

    Full Text Available Abstract Laterally close-packed quantum dots (QDs called quantum dot molecules (QDMs are grown by modified molecular beam epitaxy (MBE. Quantum dots could be aligned and cross hatched. Quantum rings (QRs created from quantum dot transformation during thin or partial capping are used as templates for the formations of bi-quantum dot molecules (Bi-QDMs and quantum dot rings (QDRs. Preferable quantum dot nanostructure for quantum computation based on quantum dot cellular automata (QCA is laterally close-packed quantum dot molecules having four quantum dots at the corners of square configuration. These four quantum dot sets are called quadra-quantum dots (QQDs. Aligned quadra-quantum dots with two electron confinements work like a wire for digital information transmission by Coulomb repulsion force, which is fast and consumes little power. Combination of quadra-quantum dots in line and their cross-over works as logic gates and memory bits. Molecular Beam Epitaxial growth technique called ‘‘Droplet Epitaxy” has been developed for several quantum nanostructures such as quantum rings and quantum dot rings. Quantum rings are prepared by using 20 ML In-Ga (15:85 droplets deposited on a GaAs substrate at 390°C with a droplet growth rate of 1ML/s. Arsenic flux (7–8×10-6Torr is then exposed for InGaAs crystallization at 200°C for 5 min. During droplet epitaxy at a high droplet thickness and high temperature, out-diffusion from the centre of droplets occurs under anisotropic strain. This leads to quantum ring structures having non-uniform ring stripes and deep square-shaped nanoholes. Using these peculiar quantum rings as templates, four quantum dots situated at the corners of a square shape are regrown. Two of these four quantum dots are aligned either or , which are preferable crystallographic directions of quantum dot alignment in general.

  1. Synthesis and characterization of -phosphorylated thioureas RNHC(S)NHP(O)(OPr)2 (R = 2-MeC6H4, 2,6-Me2C6H3, 2,4,6-Me3C6H2)

    Indian Academy of Sciences (India)

    Damir A Safin; Maria G Babashkina; Michael Bolte; Axel Klein

    2010-05-01

    Reaction of O,O'-diisopropylphosphoric acid isothiocyanate (PrO)2P(O)NCS with 2-methylaniline 2-MeC6H4NH2, 2,6-dimethylaniline 2,6-Me2C6H3NH2 or 2,4,6-trimethylaniline 2,4,6-Me3C6H2NH2 leads to the -phosphorylated thioureas RNHC(S)NHP(O)(OPr)2 (R = 2-MeC6H4-, HLI; 2,6-Me2C6H3-, HLII; 2,4,6-Me3C6H2-, HLIII). The new compounds were investigated by 1H and 31P{1H} NMR spectroscopy, and microanalysis. The molecular structure of the thiourea HLIII was elucidated by single crystal X-ray diffraction analysis. Single crystal X-ray diffraction studies showed HLIII forms both intra- and intermolecular hydrogen bonds, which in turn leads to the formation of polymeric chains. One of the intermolecular hydrogen bonds is of the type N-H$\\cdots$S. Moreover, the formation of intermolecular C-H$\\cdots$ 6 -phenyl interactions was established.

  2. F6H8 as an Intraoperative Tool and F6H8/Silicone Oil as a Postoperative Tamponade in Inferior Retinal Detachment with Inferior PVR

    Directory of Open Access Journals (Sweden)

    Gian Marco Tosi

    2014-01-01

    Full Text Available Purpose. To evaluate the effectiveness and safety of perfluorohexyloctane (F6H8 for intraoperative flattening of the retina and of F6H8/silicone oil (SO 1000 cSt as a postoperative tamponade for inferior retinal detachment with inferior proliferative vitreoretinopathy. Methods. This is a retrospective review of 22 patients who underwent pars plana vitrectomy using F6H8 as an intraoperative tool to flatten the retina. At the end of the surgery a direct partial exchange between F6H8 and SO 1000 cSt was performed, tamponing the eye with different ratios of F6H8/SO (70/30, 60/40, 50/50, 40/30, and 30/70. Anatomical and functional results and complications were evaluated over the follow-up period (mean 22.63 months. Results. F6H8 was efficacious for intraoperative flattening of the retina. Twenty-one of the 22 patients achieved a complete retinal reattachment. Postoperative visual acuity (VA ranged from light perception to 20/70, with 72% of patients obtaining VA better than 20/400. No emulsification/inflammation was observed whatever the ratio of F6H8/SO used. With higher ratios of F6H8/SO (70/30 and 60/40 cloudiness of the tamponade was observed. A transparent mixture was present with all the other ratios. Conclusions. The surgical technique adopted is very simple and safe. The optimal F6H8/SO ratio seems to be between 50/50 and 30/70.

  3. The first potential energy surfaces for the C6H--H2 and C6H--He collisional systems and their corresponding inelastic cross sections

    Science.gov (United States)

    Walker, Kyle M.; Dumouchel, Fabien; Lique, François; Dawes, Richard

    2016-07-01

    Molecular anions have recently been detected in the interstellar and circumstellar media. Accurate modeling of their abundance requires calculations of collisional data with the most abundant species that are usually He atoms and H2 molecules. In this paper, we focus on the collisional excitation of the first observed molecular anion, C6H-, by He and H2. Theoretical calculations of collisional cross sections rely generally on ab initio interaction potential energy surfaces (PESs). Hence, we present here the first PESs for the C6H--H2 and C6H--He van der Waals systems. The ab initio energy data for the surfaces were computed at the explicitly correlated coupled cluster with single, double, and scaled perturbative triple excitations level of theory. The method of interpolating moving least squares was used to construct 4D and 2D analytical PESs from these data. Both surfaces are characterized by deep wells and large anisotropies. Analytical models of the PESs were used in scattering calculations to obtain cross sections for low-lying rotational transitions. As could have been anticipated, important differences exist between the He and H2 cross sections. Conversely, no significant differences exist between the collisions of C6H- with the two species of H2 (para- and ortho-H2). We expect that these new data will help in accurately determining the abundance of the C6H- anions in space.

  4. Current status of self-organized epitaxial graphene ribbons on the C face of 6H-SiC substrates

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Nicolas; Caboni, Alessandra; Godignon, Philippe [IMB-CNM-CSIC, Campus UAB 08193-Bellaterra, Barcelona (Spain); Tiberj, Antoine; Jouault, Benoit; Jabakhanji, Bilal; Camassel, Jean [GES, UMR-CNRS 5650, Universite Montpellier 2, 34095-Montpellier cedex 5 (France); Mestres, Narcis [ICMAB-CSIC, Campus UAB 08193- Bellaterra, Barcelona (Spain)

    2010-09-22

    The current status of long, self-organized, epitaxial graphene ribbons grown on the (0 0 0 -1) face of 6H-SiC substrates is reviewed. First, starting from the early stage of growth it is shown that on the C face of 6H-SiC substrates the sublimation process is not homogeneous. Most of the time it starts from defective sites, dislocations or point defects, that define nearly circular flakes surrounded by bare SiC. These flakes have a volcano-like shape with a graphite chimney at the centre, where the original defect was located. At higher temperatures a complete conversion occurs, which is not yet homogeneous on the whole sample. This growth process can be modified by covering the sample with a graphite cap. It changes the physics of the surface reconstruction during the Si-sublimation process and, on the C face, makes more efficient the reconstruction of few selected terraces with respect to the others. The net result is the formation of strongly step-bunched areas with, in between, long and large reconstructed terraces covered by graphitic material. Despite the low intrinsic optical absorption of a few graphene layers on SiC, micro-transmission experiments, complemented by micro-Raman spectroscopy, demonstrate that most of this graphitic coverage is made of one or two homogeneous graphene layers. We show also that most of the thermal stress between the graphene layer and the 6H-SiC substrate is relaxed by pleats or wrinkles which are clearly visible on the AFM images. Finally, the results of transport experiments performed on the graphitic ribbons reveal the p-type character of the ribbons.

  5. Photoluminescence and Raman spectroscopy characterization of boron- and nitrogen-doped 6H silicon carbide

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Liu, Chuan;

    2011-01-01

    Boron - and nitrogen-doped 6H silicon carbide epilayers grown on low off-axis 6H silicon carbide substrates have been characterized by photoluminescence and Raman spectroscopy. Combined with secondary ion mass spectrometry results, preferable doping type and optimized concentration could...

  6. A facile microwave assisted one-pot synthesis of novel 1-methylhexahydroquinazolin-5(6H-ones and bis-1-methylhexahydroquinazolin-5(6H-ones

    Directory of Open Access Journals (Sweden)

    Madhusudhan Saha

    2011-03-01

    Full Text Available Novel hexahydroquinazolin-5(6H-ones 3a-j have been synthesized in good yields by the reaction of enaminones 2a-b with primary amines and formaldehyde under the influence microwaves. Enaminones 2a-b have also been reacted with diamines and formaldehyde under similar conditions resulting in hitherto unreported bis- hexahydroquinazolin-5(6H-ones 4a-d and 5a-d. The structures of the molecules have been established with the help of spectral and analytical data.

  7. Electron Transfer Reaction between M-C6H6 and M+-C6H6 Complexes in the Gas Phase: Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    DFT/BLYP method is used to theoretically investigate the electron transfer (ET) reactions between M (Li, Na, Mg)-C6H6 and M+-C6H6 complexes in the gas phase. The geometry optimization of the precursor complexes and the transition state in the process of ET reaction was performed at 6-31G basis set level. The activation energy, the coupling matrix element and the rate constant of the ET reaction are calculated at semi-quantitative level.

  8. Heat of Mixing and Solution of Cyclohexanone C6H10O + C6H12O Cyclohexanol (HMSD1121, LB4187_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Cyclohexanone C6H10O + C6H12O Cyclohexanol (HMSD1121, LB4187_H)' providing data from direct calorimetric measurement of molar excess enthalpy at variable mole fraction and constant pressure and temperature.

  9. Volumetric Properties of the Mixture Benzene C6H6 + C6H10O Cyclohexanone (VMSD1212, LB4824_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Benzene C6H6 + C6H10O Cyclohexanone (VMSD1212, LB4824_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  10. Vapor-Liquid Equilibrium in the Mixture Cyclohexanone C6H10O + C6H12O Cyclohexanol (EVLM1111, LB5657_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Cyclohexanone C6H10O + C6H12O Cyclohexanol (EVLM1111, LB5657_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  11. Volumetric Properties of the Mixture Benzene C6H6 + C6H10O Cyclohexanone (VMSD1111, LB4819_V0029

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Benzene C6H6 + C6H10O Cyclohexanone (VMSD1111, LB4819_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  12. Volumetric Properties of the Mixture Benzene C6H6 + C6H10O Cyclohexanone (VMSD1511, LB4829_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Benzene C6H6 + C6H10O Cyclohexanone (VMSD1511, LB4829_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  13. Genomic structure of bacteriophage 6H and its distribution as prophage in Flavobacterium psychrophilum strains

    DEFF Research Database (Denmark)

    Castillo Bermúdez, Daniel Elías; Espejo, Romilio; Middelboe, Mathias

    2014-01-01

    . Here, we present the genome sequence of F. psychrophilum bacteriophage 6H and its distribution as prophage in F. psychrophilum isolates. The DNA sequence revealed a genome of 46 978 bp containing 63 predicted ORFs, of which 13% was assigned a putative function, including an integrase. Sequence analysis...... for the presence of four phage 6H genes (integrase, tail tape protein and two hypothetical proteins) by PCR showed the presence of these prophage genes in 80% of the isolates. In conclusion, we hypothesize that bacteriophage 6H belongs to an abundant group of temperate phages which has lysogenized a large fraction...

  14. 75 FR 62005 - Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350...

    Science.gov (United States)

    2010-10-07

    ... proposed AD. Discussion On August 18, 2009, we issued AD 2009-18-03, Amendment 39-15999 (74 FR 43636... rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will.... 39.13 by removing Amendment 39-15999 (74 FR 43636; August 27, 2009), and adding the following new...

  15. X-ray diffraction study of p-(alkoxybenzylidene)-p'-toluidines C2H5O-C6H4-CH=N-C6H4-CH3 and C4H9O-C6H4-CH=N-C6H4-CH3

    International Nuclear Information System (INIS)

    The molecular and crystal structures of two p-alkoxybenzylidene)-p'-toluidines C2H5O-C6H4-CH=N-C6H4-CH3 (1) and C4H9O-C6H4-CH=N-C6H4-CH3 (2) are determined by X-ray diffraction. Crystals 1 and 2 contain four and two crystallographically independent molecules, respectively. In 1, the geometry of the independent molecules is almost identical. In 2, the independent molecules differ in the conformation of the alkyl chain, which is disordered in one of them. An analysis of the crystal packing of 2 reveals the alternation of spacious layers formed by loosely packed aliphatic fragments of molecules and layers of closely packed aromatic fragments, which ensures the formation of the mesogenic phase in the course of melting of crystals 2. In crystal 1, loose aliphatic layers are absent.

  16. Coordination chemistry of silver(I) with the nitrogen-bridged ligands (C(6)H(5))(2)PN(H)P(C(6)H(5))(2) and (C(6)H(5))(2)PN(CH(3))P(C(6)H(5))(2): the effect of alkylating the nitrogen bridge on ligand bridging versus chelating behavior.

    Science.gov (United States)

    Sekabunga, E J; Smith, Michele L; Webb, T R; Hill, W E

    2002-03-11

    The coordination chemistry of silver(I) with the nitrogen-bridged ligands (C(6)H(5))(2)PN(R)P(C(6)H(5))(2) [R = H (dppa); R = CH(3) (dppma)] has been investigated by (31)P NMR and electrospray mass spectrometry (ESMS). Species observed by (31)P NMR include Ag(2)(mu-dppa)(2+), Ag(2)(mu-dppa)(2)(2+), Ag(2)(mu-dppa)(3)(2+), Ag(2)(mu-dppma)(2+), Ag(2)(mu-dppma)(2)(2+), and Ag(eta(2)-dppma)(2)(+). Species observed by ESMS at low cone voltages were Ag(2)(dppa)(2)(2+), Ag(2)(dppa)(3)(2+), Ag(2)(dppma)(2)(2+), and Ag(dppma)(2)(+). (C(6)H(5))(2)PN(CH(3))P(C(6)H(5))(2) showed a strong tendency to chelate, while (C(6)H(5))(2)PN(H)P(C(6)H(5))(2) preferred to bridge. Differences in the bridging versus chelating behavior of the ligands are assigned to the Thorpe-Ingold effect, where the methyl group on nitrogen sterically interacts with the phenyl groups on phosphorus. The crystal structure of the three-coordinate dinuclear silver(I) complex (Ag(2)[(C(6)H(5))(2)PN(H)P(C(6)H(5))(2)](3))(BF(4))(2) has been determined. Bond distances include Ag-Ag = 2.812(1) A, Ag(1)-P(av) = 2.492(3) A, and Ag(2)-P(av) = 2.509(3) A. The compound crystallizes in the monoclinic space group Cc at 294 K, with a = 18.102(4)(o), Z = 4, V = 7261(3) A(3), R = 0.0503, and R(W) = 0.0670. PMID:11874357

  17. Structure and Bonding of Ni(C6H4-nFn)(CO)2 (C6H4=benzyne, n=1-4) Complexes

    International Nuclear Information System (INIS)

    The electronic structure and properties of Ni(C6H4-nFn)(CO)2 (C6H4=benzyne, n=1-4) complexes have been investigated using hybrid density functional B3LYP theory. Both aromatic natures and nucleus independent chemical shift (NICS) of the benzyne rings have been analyzed. Among mono-, di-, and tri-fluorinated complexes, 3-F, 3,6-F, and 4-H are the most stable isomers, respectively. NICS values calculated at the several points above the ring centers are consistent with those based on the relative energies of the complexes. The atoms in molecules (AIM) analysis indicates that Ni-C bond distance is well correlated with the electron density of a ring critical point (ρrcp) in all species

  18. Global reaction route mapping of isomerization pathways of exotic C{sub 6}H molecular species

    Energy Technology Data Exchange (ETDEWEB)

    Vikas,, E-mail: qlabspu@pu.ac.in, E-mail: qlabspu@yahoo.com; Kaur, Gurpreet [Quantum Chemistry Group, Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160 014 (India)

    2013-12-14

    C{sub 6}H radical is known to exist in the astrophysical environment in linear form; however, it may originate from nonlinear isomeric forms. Potential energy surface of C{sub 6}H is explored to search isomers of C{sub 6}H and transition states connecting them. This work reports first-ever identification of reaction pathways for isomerization of C{sub 6}H. The reaction route search is performed through global reaction route mapping method, which utilizes an uphill walking technique based on an anharmonic downward distortion following approach to search intermediates and transition states. The computations performed at the CASSCF/aug-cc-pVTZ, CCSD(T)/6-311++G(d,p)//DFT/B3LYP/6-311++G(d,p), and DFT/B3LYP/aug-cc-pVTZ levels of the theory identified 14 isomers (including 8 new isomeric forms of C{sub 6}H) and 28 transition states. Most of the identified isomers are found to have significant multireference character. The kinetic stability and natural bond orbital analysis of the identified isomers is also investigated. The isomeric forms are further characterized using spectral analysis involving rotational constants, vibrational frequencies, and Raman scattering activities as well as analyzing the effect of isotopic substitution of hydrogen on the spectral features. This study proposes that the linear-C{sub 6}H can readily isomerize to a six-member ring isomer.

  19. Defect Characterization of 6H-SiC Studied by Slow Positron Beam%6H-SiC缺陷的慢正电子研究

    Institute of Scientific and Technical Information of China (English)

    王海云; 翁惠民; 周先意

    2008-01-01

    The defect formation and annealing behavior in as-grown and electron-irradiated 6H-SiC wafers were investi-gated by variable-energy slow positron beam.For the n-type as-grown samples.it was found that annealing decreased the defect concentration due to recombination with interstitial.and when it was annealed at 1400℃ for 30 min in vacuum,a 20 nm thick Si layer was found on the top of SiC substrate.which is a direct proof of the Si atom diffusing to the surface when annealed at the high temperature stages.During the high temperature annealing stage,we found an obvious surface effect occurred that induced the higher S parameter close to the surface.This may be caused by the diflusion of the Si atoms to the surface during annealing.After 10 MeV electron irradiation of the n-type 6H-SiC,the positron effective diffusion length decreased from 86.2 nm to 39.1 nm.This shows that there are some defects created in n-type 6H-SiC.But in the p-type 6H-SiC irradiated by 10 MeV electrons,the change is very small.This may be because of the opposite charge of the vacancy defects.The same annealing behavior as that of as-grown 6H-SiC samples was also observed for the 1.8 MeV electron-irradiated 6H-SiC samples except that after being annealed at 300℃,its defect concentration increased.This may be explained 88 the generation of carbon vacancies.due to either the recombination between divacancies and silicon interstitial,or the charge of the charge states.%利用单能慢正电子束流,对原生的和经过电子辐照的6H-SiC内的缺陷形成及其退火行为进行研究.发现在n型6H-SiC中,经过退火后缺陷浓度降低.这主要是因为在退火过程中缺陷和间隙子的相互作用所引起.n型6H-Si经过1400℃、30 min真空退火后,在SiC表面形成一个大约20 nm的Si层,这是在高温退火过程中Si原子向表面逸出的有力证明.在高温退火中,在样品的近表面区域有一个明显的表面效应,既在这些区域的S参数整体较

  20. Recrystallization of He-ion implanted 6H-SiC upon annealing

    International Nuclear Information System (INIS)

    Highlights: •Solid phase epitaxial growth of amorphous 6H-SiC was investigated. •Recrystallization initially nucleates and grows at the interface between the amorphous layer and 6H-SiC substrate. •Recrystallization rate is related to the implantation-induced damage and concentration of He impurity. •The region of recrystallization contains 3C-SiC and 6H-SiC with different crystalline orientations. -- Abstract: Solid phase epitaxial growth of amorphous 6H-SiC created by 15 keV He ion implantation to doses of 1.5 × 1016, 5 × 1016 and 1 × 1017 cm−2 at room temperature (RT) followed by annealing ranging from 600 °C to 900 °C for 30 min was investigated. The recrystallization process was investigated via cross-sectional transmission electron microscopy (XTEM). Recrystallization initially nucleates and grows at the interface between the amorphous layer and 6H-SiC substrate. In the middle of the amorphous layer, recrystallization nucleation is inhibited. Recrystallization rate is related to the implantation-induced damage and concentration of He impurity. The Fourier transformed images denote that the region of recrystallization contains 3C-SiC and 6H-SiC with different crystalline orientations. Besides, for the 1 × 1017 cm−2 implanted sample, partial areas are kept amorphous in the damaged layer. The threshold temperature of full recrystallization of He ion-implantation-induced amorphization in 6H-SiC and the previous observations on other ions implantation, such as Ne, Ar, Xe etc is compared. The possible reasons are discussed

  1. Lateral spread of implanted ion distributions in 6H-SiC: simulation

    Energy Technology Data Exchange (ETDEWEB)

    Morvan, E.; Flores, D.; Vellvehi, M.; Rebollo, J. [Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Centro Nacional de Microelectronica; Mestres, N. [Inst. de Ciencia de Materials (CSIC), Bellaterra (Spain); Pascual, J. [Dept. de Fisica, Univ. Autonoma de Barcelona (Spain)

    1999-07-30

    In this paper, Monte Carlo simulation, using improved models for electronic stopping and 3D damage accumulation has been carried out to calculate the lateral distribution of ions implanted into 6H-SiC crystal. Two dimensional concentration contour plots are used to show the lateral spread of implanted Al{sup +} ions at mask edges. It appears that channeling strongly influences the shape of lateral distributions due to the capture of random implanted ions by axial channels lying parallel to the (0001) surface of 6H-SiC which appears alternatively every 30 around the left angle 0001 right angle axis, according to the symmetry of the 6H-SiC crystal. This phenomenon, if confirmed by SIMS 2D profiling, could have important consequences on the behavior of ion implanted lateral junctions of SiC devices. (orig.)

  2. Optical Characterization of 4H-,6H- and 15R-SiC Crystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The optical absorption of 4H-, 6H- and 15R-SiC single crystals has been measured at room temperature. The band gaps were calculated, and the reasons for band gap shrinking were discussed. Influence of free carrier concentration was considered. The first- and second-order Raman spectra of 4H-, 6H- and 15R-SiC samples were analyzed. Raman spectra of disorder structure in 6H-SiC grown by Lely method were given and simulated. The low wave-number Raman spectrum is a reliable method to distinguish the SiC polytypes. We analyzed the similarity of the second-order Raman spectra of all polytypes.

  3. Two isomers of C6H6F9O9Tb

    International Nuclear Information System (INIS)

    Two isomeric forms of terbium tetrahydrate trifluoroacetate, featuring the composition C6H6F9O9Tb, were prepared as a result of interaction between terbium hydroxide or carbonate and trifluoroacetic acid. The compounds were characterized by the methods of elementary analysis, IR spectroscopy and X-ray diffraction analysis. It has been ascertained that isomerism of the compounds stems from different positions of protons. Crystals of both forms are isostructural, forming a continuous series of solid solutions with C6H6F9O9Eu

  4. Palladium-catalyzed cross coupling reactions of 4-bromo-6H-1,2-oxazines

    Directory of Open Access Journals (Sweden)

    Reinhold Zimmer

    2009-09-01

    Full Text Available A number of 4-aryl- and 4-alkynyl-substituted 6H-1,2-oxazines 8 and 9 have been prepared in good yields via cross coupling reactions of halogenated precursors 2, which in turn are easily accessible by bromination of 6H-1,2-oxazines 1. Lewis-acid promoted reaction of 1,2-oxazine 9c with 1-hexyne provided alkynyl-substituted pyridine derivative 12 thus demonstrating the potential of this approach for the synthesis of pyridines.

  5. Kinetics of thermal oxidation of 6H silicon carbide in oxygen plus trichloroethylene

    OpenAIRE

    Yang, BL; Lin, LM; Lo, HB; Lai, PT; Chan, CL

    2005-01-01

    In this work, the behaviors of the trichloroethylene (TCE) thermal oxidation of 6H silicon carbide (SiC) are investigated. The oxide growth of 6H SiC under different TCE concentrations (ratios of TCE to O2) follows the linear-parabolic oxidation law derived for silicon oxidation by Deal and Grove, J. Appl. Phys., 36 (1965). The oxidation rate with TCE is much higher than that without TCE and strongly depends on the TCE ratio in addition to oxidation temperature and oxidation time. The increas...

  6. File list: Oth.Emb.05.AllAg.1-6h_embryos [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Emb.05.AllAg.1-6h_embryos dm3 TFs and others Embryo 1-6h embryos SRX033315,SRX0...26864 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Emb.05.AllAg.1-6h_embryos.bed ...

  7. File list: Unc.Emb.20.AllAg.1-6h_embryos [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Emb.20.AllAg.1-6h_embryos dm3 Unclassified Embryo 1-6h embryos SRX026866,SRX026...865,SRX033316,SRX033317 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Emb.20.AllAg.1-6h_embryos.bed ...

  8. Formation and ordering of epitaxial quantum dots

    Science.gov (United States)

    Atkinson, Paola; Schmidt, Oliver G.; Bremner, Stephen P.; Ritchie, David A.

    2008-10-01

    Single quantum dots (QDs) have great potential as building blocks for quantum information processing devices. However, one of the major difficulties in the fabrication of such devices is the placement of a single dot at a pre-determined position in the device structure, for example, in the centre of a photonic cavity. In this article we review some recent investigations in the site-controlled growth of InAs QDs on GaAs by molecular beam epitaxy. The method we use is ex-situ patterning of the GaAs substrate by electron beam lithography and conventional wet or dry etching techniques to form shallow pits in the surface which then determine the nucleation site of an InAs dot. This method is easily scalable and can be incorporated with marker structures to enable simple post-growth lithographic alignment of devices to each site-controlled dot. We demonstrate good site-control for arrays with up to 10 micron spacing between patterned sites, with no dots nucleating between the sites. We discuss the mechanism and the effect of pattern size, InAs deposition amount and growth conditions on this site-control method. Finally we discuss the photoluminescence from these dots and highlight the remaining challenges for this technique. To cite this article: P. Atkinson et al., C. R. Physique 9 (2008).

  9. Microstructural and superconducting properties of C6H6 added bulk MgB2 superconductor

    Science.gov (United States)

    Babaoğlu, Meral G.; Safran, Serap; Çiçek, Özlem; Ağıl, Hasan; Ertekin, Ercan; Hossain, Md. Shahriar A.; Yanmaz, Ekrem; Gencer, Ali

    2012-10-01

    The effect of aromatic hydrocarbon (benzene, C6H6) addition on lattice parameters, microstructure, critical temperature (Tc), critical current density (Jc) of bulk MgB2 has been studied. In this work only 2 mol% C6H6 addition was found to be very effective in increasing the Jc values, while resulting in slight reduction of the Tc. Jc values of 2 mol% C6H6 added MgB2 bulks reached to 1.83×106 A/cm2 at 15 K and 0 T. Microstructural analyses suggest that Jc enhancement is associated with the substitution of carbon with boron and which also results in the smaller MgB2 grain size. The change in the lattice parameters or the lattice disorder is claimed as a cause of the slight reduction in the Tc by carbon addition. We note that our results show the advantages of C6H6 addition include homogeneous mixing of precursor powders, avoidance of expansive nanoadditives, production of highly reactive C, and significant enhancement in Jc of MgB2, compared to un-doped samples.

  10. N-VSi-related center in non-irradiated 6H SiC nanostructure

    International Nuclear Information System (INIS)

    We present the first findings of the vacancy-related centers identified by the electron spin resonance (ESR) and electrically-detected (ED) ESR method in the non-irradiated 6H-SiC nanostructure. This planar 6H-SiC nanostructure represents the ultra-narrow p-type quantum well confined by the δ-barriers heavily doped with boron on the surface of the n-type 6H-SiC (0001) wafer. The EDESR method by measuring the only magnetoresistance of the 6H SiC nanostructure under the high frequency generation from the δ-barriers appears to allow the identification of the silicon vacancy centers as well as the triplet center with spin state S=1. The same triplet center that is characterized by the larger value of the zero-field splitting constant D and anisotropic g-factor is revealed by the ESR (X-band) method. The hyperfine (hf) lines in the ESR and EDESR spectra originating from the hf interaction with the 14N nucleus allow us to attribute this triplet center to the N-VSi defect

  11. Silicon vacancy-related centers in non-irradiated 6H-SiC nanostructure

    International Nuclear Information System (INIS)

    We present the first findings of the silicon vacancy related centers identified in the non-irradiated 6H-SiC nanostructure using the electron spin resonance (ESR) and electrically-detected (ED) ESR technique. This planar 6H-SiC nanostructure represents the ultra-narrow p-type quantum well confined by the δ-barriers heavily doped with boron on the surface of the n-type 6H-SiC(0001) wafer. The new EDESR technique by measuring the only magnetoresistance of the 6H-SiC nanostructure under the high frequency generation from the δ-barriers appears to allow the identification of the isolated silicon vacancy centers as well as the triplet center with spin state S = 1. The same triplet center that is characterized by the large value of the zero-field splitting constant D and anisotropic g-factor is revealed by the ESR (X-band) method. The hyperfine (HF) lines in the ESR and EDESR spectra originating from the HF interaction with the 14N nucleus seem to attribute this triplet center to the N-VSi defect

  12. Silicon vacancy-related centers in non-irradiated 6H-SiC nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, N. T., E-mail: Impurity.Dipole@mail.ioffe.ru; Danilovskii, E. Yu.; Gets, D. S. [Russian Academy of Sciences, Ioffe Physicaltechnical Institute (Russian Federation); Kalabukhova, E. N. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine); Klyachkin, L. E.; Koudryavtsev, A. A.; Malyarenko, A. M. [Russian Academy of Sciences, Ioffe Physicaltechnical Institute (Russian Federation); Mashkov, V. A. [State Polytechnical University (Russian Federation); Savchenko, D. V.; Shanina, B. D. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine)

    2015-05-15

    We present the first findings of the silicon vacancy related centers identified in the non-irradiated 6H-SiC nanostructure using the electron spin resonance (ESR) and electrically-detected (ED) ESR technique. This planar 6H-SiC nanostructure represents the ultra-narrow p-type quantum well confined by the δ-barriers heavily doped with boron on the surface of the n-type 6H-SiC(0001) wafer. The new EDESR technique by measuring the only magnetoresistance of the 6H-SiC nanostructure under the high frequency generation from the δ-barriers appears to allow the identification of the isolated silicon vacancy centers as well as the triplet center with spin state S = 1. The same triplet center that is characterized by the large value of the zero-field splitting constant D and anisotropic g-factor is revealed by the ESR (X-band) method. The hyperfine (HF) lines in the ESR and EDESR spectra originating from the HF interaction with the {sup 14}N nucleus seem to attribute this triplet center to the N-V{sub Si} defect.

  13. CMS Centre at CERN

    CERN Multimedia

    2007-01-01

    A new "CMS Centre" is being established on the CERN Meyrin site by the CMS collaboration. It will be a focal point for communications, where physicists will work together on data quality monitoring, detector calibration, offline analysis of physics events, and CMS computing operations. Construction of the CMS Centre begins in the historic Proton Synchrotron (PS) control room. The historic Proton Synchrotron (PS) control room, Opened by Niels Bohr in 1960, will be reused by CMS to built its control centre. TThe LHC@FNAL Centre, in operation at Fermilab in the US, will work very closely with the CMS Centre, as well as the CERN Control Centre. (Photo Fermilab)The historic Proton Synchrotron (PS) control room is about to start a new life. Opened by Niels Bohr in 1960, the room will be reused by CMS to built its control centre. When finished, it will resemble the CERN Contro...

  14. Molybdenum complexes derived from the oxydianiline [(2-NH2C6H4)2O]: synthesis, characterization and ε-caprolactone ROP capability.

    Science.gov (United States)

    Yang, Wenxue; Zhao, Ke-Qing; Redshaw, Carl; Elsegood, Mark R J

    2015-08-01

    The reaction of Na2MoO4 with 2,2'-oxydianiline (2-aminophenylether), (2-NH2C6H4)2O, LH4, in DME (DME = 1,2-dimethoxyethane) in the presence of Et3N and Me3SiCl afforded either the bis(imido) molybdenum(vi) complex {Mo(L)Cl2(DME)} (), where L = (2-NC6H4)2O, or the molybdenum(v) salt [Mo(L')Cl4][Et3NH] (), where L' = [(2-NH2C6H4)(2-NC6H4)O], depending on the work-up method employed. The same diamine reacted with in situ [Mo(NtBu)2Cl2(DME)] afforded a tetra-nuclear complex [Mo4Cl3(NtBu)3(OSiMe3)(μ4-O)(L)2(L')2]·2MeCN (·2MeCN). The crystal structures of , and ·2MeCN have been determined. The structure of the bis(imido) complex contains two unique molecules paired up via weak π-stacking, whereas the structure of contains a chelating amine/imido ligand, and is made up of discrete units of two cations and two anions which are interacting via H-bonding. The tetra-nuclear structure contains four different types of distorted octahedral molybdenum centre, and a bent Me3SiO group thought to originate from the precursor synthesis. Complexes have been screened for their ability to ring open polymerize (ROP) ε-caprolactone. For and (not ), conversion rates were good (>90%) at high temperatures (100 °C) over 6-24 h, and the polymerization proceeded in a living manner. PMID:26107689

  15. PCl3-C6H6 heterodimers: evidence for Pπ phosphorus bonding at low temperatures.

    Science.gov (United States)

    Ramanathan, N; Sankaran, K; Sundararajan, K

    2016-07-28

    A phosphorous trichloride (PCl3)-benzene (C6H6) heterodimer was generated in a low temperature N2 matrix and was characterized using infrared spectroscopy. The structure of the heterodimer produced in the matrix isolation experiment was discerned through ab initio computations. Computations disclosed that the experimentally detected dimer is stabilized through strong non-covalent phosphorus bonded Pπ interaction, considered as a class of pnicogen bonding. This experimentally unmapped Pπ interaction so far has been reconnoitered using atoms in molecules and natural bond orbital and energy decomposition analyses. The influence of substitutions on both the PCl3 and C6H6 monomeric units of the heterodimer was subsequently examined to understand the strength of Pπ interaction as a result of these substitutions. PMID:27374927

  16. Formation of oxide-trapped charges in 6H-SiC MOS structures

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Masahito; Ohshima, Takeshi; Itoh, Hisayoshi; Nashiyama, Isamu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Okumura, Hajime; Yoshida, Sadafumi

    1997-03-01

    The silicon and the carbon faces of hexagonal silicon carbide (6H-SiC) substrates were oxidized pyrogenically at 1100degC, and the metal-oxide-semiconductor structures were formed on these faces. The MOS capacitors developed using the silicon and the carbon faces were irradiated with {sup 60}Co gamma-rays under argon atmosphere at room temperature. The bias voltages with the different polarity were applied to the gate electrode during irradiation to examine the formation mechanisms of the trapped charges in the oxides of these MOS capacitors. The amount of the trapped charges in the oxide were obtained from capacitance pulse voltage characteristics. The generation of the trapped charges are affects with not only the absorbed dose but also the bias polarity applied to the gate electrodes during irradiation. The formation mechanisms of the trapped charges in the oxides were estimated in conjunction with the surface orientation of 6H-SiC substrates. (author)

  17. Quantum dot spectroscopy

    DEFF Research Database (Denmark)

    Leosson, Kristjan

    1999-01-01

    Semiconductor quantum dots ("solid state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution...

  18. Characterization of donor-acceptor-pair emission in fluorescent 6H-SiC

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Linnarsson, Margareta;

    Boron (B)- and nitrogen (N)-codoped 6H-SiC epilayer exhibits strong donor to acceptor pair (DAP) band luminescence which makes it a promising candidate for the white light emitting diode (LED) [1]. To investigate the optimized dopant concentrations, five samples with the same B concentration leve...... and N concentrations exceeding 1018 cm-3. Also the their difference should be larger than 4 x 1018 cm-3....

  19. Client Centred Desing

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Nielsen, Janni; Levinsen, Karin

    2008-01-01

    In this paper we argue for the use of Client Centred preparation phases when designing complex systems. Through Client Centred Design human computer interaction can extend the focus on end-users to alse encompass the client's needs, context and resources.......In this paper we argue for the use of Client Centred preparation phases when designing complex systems. Through Client Centred Design human computer interaction can extend the focus on end-users to alse encompass the client's needs, context and resources....

  20. Canadian Irradiation Centre

    International Nuclear Information System (INIS)

    The Canadian Irradiation Centre is a non-profit cooperative project between Atomic Energy of Canada Limited, Radiochemical Company and Universite du Quebec, Institut Armand-Frappier, Centre for Applied Research in Food Science. The Centre's objectives are to develop, demonstrate and promote Canada's radiation processing technology and its applications by conducting applied research; training technical, professional and scientific personnel; educating industry and government; demonstrating operational and scientific procedures; developing processing procedures and standards, and performing product and market acceptance trials. This pamphlet outlines the history of radoation technology and the services offered by the Canadian Irradiation Centre

  1. A nonsense mutation in PDE6H causes autosomal-recessive incomplete achromatopsia.

    Science.gov (United States)

    Kohl, Susanne; Coppieters, Frauke; Meire, Françoise; Schaich, Simone; Roosing, Susanne; Brennenstuhl, Christina; Bolz, Sylvia; van Genderen, Maria M; Riemslag, Frans C C; Lukowski, Robert; den Hollander, Anneke I; Cremers, Frans P M; De Baere, Elfride; Hoyng, Carel B; Wissinger, Bernd

    2012-09-01

    Achromatopsia (ACHM) is an autosomal-recessive retinal dystrophy characterized by color blindness, photophobia, nystagmus, and severely reduced visual acuity. Its prevalence has been estimated to about 1 in 30,000 individuals. Four genes, GNAT2, PDE6C, CNGA3, and CNGB3, have been implicated in ACHM, and all encode functional components of the phototransduction cascade in cone photoreceptors. Applying a functional-candidate-gene approach that focused on screening additional genes involved in this process in a cohort of 611 index cases with ACHM or other cone photoreceptor disorders, we detected a homozygous single base change (c.35C>G) resulting in a nonsense mutation (p.Ser12(∗)) in PDE6H, encoding the inhibitory γ subunit of the cone photoreceptor cyclic guanosine monophosphate phosphodiesterase. The c.35C>G mutation was present in three individuals from two independent families with a clinical diagnosis of incomplete ACHM and preserved short-wavelength-sensitive cone function. Moreover, we show through immunohistochemical colocalization studies in mouse retina that Pde6h is evenly present in all retinal cone photoreceptors, a fact that had been under debate in the past. These findings add PDE6H to the set of genes involved in autosomal-recessive cone disorders and demonstrate the importance of the inhibitory γ subunit in cone phototransduction. PMID:22901948

  2. Surface topography in mechanical polishing of 6H-SiC (0001) substrate

    Science.gov (United States)

    Yin, Ling; Huang, Han

    2007-12-01

    Silicon carbide (SiC) single crystals have been used as the substrates of a new generation of wide band-gap semiconductors due to their unparalleled combination of high breakdown voltage, extreme temperature tolerance, mobility and radiation hardness. For their applications, the SiC substrates need to be machined with nanometric surface quality as well as high form accuracy. However, the superior properties of the materials render their machinability extremely difficult. In this paper, we report the form error and surface roughness of the 6H-SiC (0001) substrate mechanically polished using 3 μm diamond powders in two different polishing processes. One process was concentrated-load polishing; the other was surface polishing. The polished surfaces were evaluated using white light interferometry and atomic force microscopy (AFM) for assessment of two- and three-dimensional topographies including form error and surface roughness. We found that a large form error was produced on the 6H-SiC (0001) substrate in the concentrated-load polishing. The root-mean-square (RMS) surface roughness of approximately 4 nm was resulted. Surface polishing of the 6H-SiC (0001) substrate remarkably improved form accuracy. The RMS surface roughness of approximately 2.5 nm was obtained.

  3. Synergistic effects of iodine and silver ions co-implanted in 6H-SiC

    Science.gov (United States)

    Kuhudzai, R. J.; Malherbe, J. B.; Hlatshwayo, T. T.; van der Berg, N. G.; Devaraj, A.; Zhu, Z.; Nandasiri, M.

    2015-12-01

    Motivated by the aim of understanding the release of fission products through the SiC coating of fuel kernels in modern high temperature nuclear reactors, a fundamental investigation is conducted to understand the synergistic effects of implanted silver (Ag) and iodine (I) in 6H-SiC. The implantation of the individual species, as well as the co-implantation of 360 keV ions of I and Ag at room temperature in 6H-SiC and their subsequent annealing behaviour has been investigated by Secondary Ion Mass Spectrometry (SIMS), Atom Probe Tomography (APT) and X-ray Photoelectron Spectroscopy (XPS). SIMS and APT measurements indicated the presence of Ag in the co-implanted samples after annealing at 1500 °C for 30 h in sharp contrast to the samples implanted with Ag only. In samples implanted with Ag only, complete loss of the implanted Ag was observed. However, for I only implanted samples, some iodine was retained. APT of annealed co-implanted 6H-SiC showed clear spatial association of Ag and I clusters in SiC, which can be attributed to the observed I assisted retention of Ag after annealing. Such detailed studies will be necessary to identify the fundamental mechanism of fission products migration through SiC coatings.

  4. Characteristics of the SF6/H2 laser initiated by an axially injected electron-beam

    International Nuclear Information System (INIS)

    The experimental and analytical studies on the characteristics of SF6/H2 laser were performed. The experimental apparatus consisted of a low-impedance Marx generator, an electric field emission diode, a laser tube, and an axial field coil. The electron beam of 320 KeV and 2.5 kA was injected into SF6/H2 gas. A simulation model to derive laser parameters is the rate equation model which includes ignition reaction, excitation reaction and relaxation reaction. The laser energy, the wave form of laser pulses, photon production rate and the number of produced molecules of HF were derived from the model. The maximum laser power was 450 mJ with the FWHM of 160 ns, when the gas mixing ratio of SF6/H2 was 11 to 1 and the gas pressure was 120 Torr. The optimum length of a laser tube was about 500 mm. The generation efficiency of laser was 4.9 percent. The values of laser parameters obtained from the simulation were 2.0 x 10-3 of the F atom dissociation of SF6 and 15.7 eV/F of the production energy of one F atom. (Kato, T.)

  5. Zero-Point Corrections for Isotropic Coupling Constants for Cyclohexadienyl Radical, C6H7 and C6H6Mu: Beyond the Bond Length Change Approximation

    Directory of Open Access Journals (Sweden)

    Bruce S. Hudson

    2013-04-01

    Full Text Available Zero-point vibrational level averaging for electron spin resonance (ESR and muon spin resonance (µSR hyperfine coupling constants (HFCCs are computed for H and Mu isotopomers of the cyclohexadienyl radical. A local mode approximation previously developed for computation of the effect of replacement of H by D on 13C-NMR chemical shifts is used. DFT methods are used to compute the change in energy and HFCCs when the geometry is changed from the equilibrium values for the stretch and both bend degrees of freedom. This variation is then averaged over the probability distribution for each degree of freedom. The method is tested using data for the methylene group of C6H7, cyclohexadienyl radical and its Mu analog. Good agreement is found for the difference between the HFCCs for Mu and H of CHMu and that for H of CHMu and CH2 of the parent radical methylene group. All three of these HFCCs are the same in the absence of the zero point average, a one-parameter fit of the static HFCC, a(0, can be computed. That value, 45.2 Gauss, is compared to the results of several fixed geometry electronic structure computations. The HFCC values for the ortho, meta and para H atoms are then discussed.

  6. Geometrical control of 3C and 6H-SiC nucleation on low off-axis substrates

    DEFF Research Database (Denmark)

    Jokubavicius, Valdas; Liljedahl, Rickard; Ou, Yiyu;

    2011-01-01

    Growth of 3C or 6H-SiC epilayers on low off-axis 6H-SiC substrates can be mastered by changing the size of the on axis plane formed by long terraces in the epilayer using geometrical control. The desired polytype can be selected in thick (~200 μm) layers of both 6H-SiC and 3C-SiC polytypes...

  7. Improved operability of the CANDU 9 control centre

    Energy Technology Data Exchange (ETDEWEB)

    Macbeth, M. J.; Webster, A. [Atomic Energy of Canada Limited, Saskatoon (Canada)

    1996-04-15

    The next generation CANDU nuclear power plant being designed by AECL is the 900 MWe class CANDU 9 station. It is based upon the Darlington CANDU station design which is among the world leaders in capacity factor with low Operation, Maintenance and Administration (OM and A) costs. This Control Centre design includes the proven functionality of existing CANDU control centres (including the Wolsong 2,3, and 4 control centre improvements, such as the Emergency Core Cooling panels), the characteristics identified by systematic design with human factors analysis of operations requirements and the advanced features needed to improve station operability which is made possible by the application of new technology. The CANDU 9 Control Centre provides plant staff with an improved operability capability due to the combination of proveness, systematic design with human factors engineering and enhanced operating features. Significant features which contribute to this improved operability include: {center_dot} Standard NSP, BOP and F/H panels with controls and indicators integrated by a standard display/presentation philosophy. {center_dot} Common plant parameter signal database for extensive monitoring, checking, display and annunciation. {center_dot} Powerful annunciation system allowing alarm filtering, prioritizing and interrogation to enhance staff recognition of events, plant state and required corrective procedural actions. {center_dot} The use of an overview display to present immediate and uncomplicated plant status information to facilitate operator awareness of unit status in a highly readable and recognizable format. {center_dot} Extensive cross checking of similar process parameters amongst themselves, with the counterpart safety system parameters and as well as with 'signature' values obtained from known steady state conditions. {center_dot} Powerful calculation capabilities, using the plant wide database, providing immediate recognizable and readable and

  8. Electronic and electrochemical properties of platinum(II) and platinum-mercury-carboxylato complexes containing 2-Me2NCH2C6H4, 2,6-(Me2NCH2)2C6H3- and 2-Me2NC6H4CH2 - ligands

    NARCIS (Netherlands)

    Koten, G. van; Ploeg, A.F.M.J. van der; Schmitz, J.E.J.; Linden, J.G.M. van der

    1982-01-01

    The organoplatinum(II) compounds [{2, 6-(Me{2}NCH{2}){2}C{6}H{3}}PtBr] and cis-[(C-N){2}Pt] (C-N = 2-Me{2}NCH{2}C{6}H{4}, 2-Me{2}NC{6}H{4}CH{2}) can be chemically irreversibly oxidized in the potential range 1.00 to 1.35 V vs. an Ag/AgCl electrode, whereas the organoplatinum@?mercury complexes [{2,6

  9. Characterization of donor–acceptor-pair emission in fluorescent 6H-SiC

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Linnarsson, Margareta;

    2012-01-01

    We investigated donor–acceptor-pair emission in N–B-doped 6H-SiC samples by using photoluminescence (PL) and angle-resolved PL. It is shown that n-type doping with concentrations larger than 1018 cm−3 is favorable for observing luminescence, and increasing nitrogen results in stronger luminescence....... A dopant concentration difference greater than 4×1018 cm−3 is proposed to help achieve intense PL. Angular-dependent PL was observed that was attributed to the Fabry–Pérot microcavity interference effect, and a strong luminescence intensity in a large emission angle range was also achieved. The results...

  10. Study of photomodulated reflectance in 6H-SiC single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gruzintsev, A. N., E-mail: gran@iptm.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and Ultra-High-Purity Materials (Russian Federation)

    2013-04-15

    The effect of ultraviolet irradiation of the surface of silicon-carbide (6H-SiC) single crystals on their optical reflectivity in the visible and violet spectral regions is studied. It is shown that the photoreflection-signal intensity is maximal, if the light beam is incident at the Brewster angle and polarized parallel to the plane of incidence. The relative change induced in the refractive index of the surface layers of a crystal (10{sup -3}) upon exposure to nitrogen laser radiation, caused by the generation of nonequilibrium free charge carriers in the conduction band of the material, is established.

  11. Isochoric thermal conductivity of solid n-alkanes: hexane C6H14

    International Nuclear Information System (INIS)

    The isochoric thermal conductivity of solid n-hexane C6H14 has been investigated on three samples of different density in the temperature interval from 100 K to the onset of melting. In all the cases the isochoric thermal conductivity varied following a dependence which is weaker than A is proportional to 1/T. The results obtained are compared with the thermal conductivities of other representatives of n-alkanes. The contributions of low-frequency phonons and 'diffuse modes' to the thermal conductivity are calculated.

  12. Multihormonal regulation of thyroglobulin production by the OVNIS 6H thyroid cell line.

    Science.gov (United States)

    Aouani, A; Hovsépian, S; Fayet, G

    1988-02-01

    The hormonal regulation of thyroglobulin production has been studied using a clone of the ovine thyroid cell line: OVNIS 6H. 3 among the 6 hormones proposed for serum replacement are required for an optimal thyroglobulin production; insulin, hydrocortisone and thyrotropin. Insulin alone stimulates thyroglobulin production. The presence of insulin is also required to observe hydrocortisone and TSH stimulations. Newborn calf serum inhibits thyroglobulin production. The best conditions for optimal thyroglobulin expression and TSH responsiveness are obtained in serum-free medium supplemented with 5 micrograms/ml insulin, 100 nM hydrocortisone and 1 mU/ml TSH. PMID:3286455

  13. Epitaxial Growth of Graphene on 6H-SiC (0001) by Thermal Annealing

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; LIU Zhong-Liang; KANG Chao-Yang; PAN Hai-Bin; WEI Shi-Qiang; XU Peng-Shou; GAO Yu-Qiang; XU Xian-Gang

    2009-01-01

    An epitaxial graphene (EG) layer is successfully grown on a Si-terminated 6H-SiC (0001) substrate by the method of thermal annealing in an ultrahigh vacuum molecular beam epitaxy chamber.The structure and morphology of the EG sample are characterized by reflection high energy diffraction (RHEED),Raman spectroscopy and atomic force microscopy (AFM).Graphene diffraction streaks can be seen in RHEED.The G and 2D peaks of graphene are clearly observed in the Raman spectrum.The AFM results show that the graphene nominal thickness is about 4-10 layers.

  14. Effect of charged microenvironment on the electrochemistry of [Fe2S2(OC6H5)4]2− cluster

    Indian Academy of Sciences (India)

    Dhanada Sarmah; Diganta Kumar Das

    2013-11-01

    Although cysteine is the preferred ligand for [Fe-S] core in case of iron-sulphur proteins, presence of other ligands together with cysteine is not uncommon. Being basically electron transfer proteins, redox potential of [Fe-S] core in these proteins in crucial to their functioning. Among other factors, charged nature of the microenvironment is believed to tune the redox potential. The iron-sulphur cluster, [Fe2S2(OC6H5)4]2−, has been investigated electrochemically in positive and negative microenvironments, both in solution and in film. Charge nature around the active centre has been found to affect its redox potential and diffusion coefficient significantly. In a film, where charges are more localized compared to solution, the effect on redox potential was more prominent.

  15. DIMERIC AND MONOMERIC CHROMIUM(II) AND MONOMERIC CHROMIUM(III) ARYLS - CRYSTAL-STRUCTURE OF PYRAMIDAL MZ2CR(PY) (MZ = ORTHO-ME2NCH2C6H4, PY = PYRIDINE), DIMERIC [(ME2NC6H4)2CR]2, AND OCTAHEDRAL (ME2NC6H4)3CR

    NARCIS (Netherlands)

    EDEMA, JJH; GAMBAROTTA, S; MEETSMA, A; SPEK, AL

    1992-01-01

    Reaction of CrCl2(THF)2 with 2 equiv of [omicron-Me2NCH2C6H4]Li and [omicron-Me2NC6H4]Li led to formation of the monomeric pyramidal [omicron-Me2NCH2C6H4]2Cr(pyridine) (2) and dimeric [(omicron-Me2NC6H4)2Cr]2 (3) with a supershort Cr-Cr contact. Both compounds can be thermolyzed in toluene to form t

  16. 6H-SiC Transistor Integrated Circuits Demonstrating Prolonged Operation at 500 C

    Science.gov (United States)

    Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith, Roger; Ferrier, Terry; Krasowski, Michael J.; Prokop, Norman F.

    2008-01-01

    The NASA Glenn Research Center is developing very high temperature semiconductor integrated circuits (ICs) for use in the hot sections of aircraft engines and for Venus exploration where ambient temperatures are well above the approximately 300 degrees Centigrade effective limit of silicon-on-insulator IC technology. In order for beneficial technology insertion to occur, such transistor ICs must be capable of prolonged operation in such harsh environments. This paper reports on the fabrication and long-term 500 degrees Centigrade operation of 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). Simple analog amplifier and digital logic gate ICs have now demonstrated thousands of hours of continuous 500 degrees Centigrade operation in oxidizing air atmosphere with minimal changes in relevant electrical parameters. Electrical characterization and modeling of transistors and circuits at temperatures from 24 degrees Centigrade to 500 degrees Centigrade is also described. Desired analog and digital IC functionality spanning this temperature range was demonstrated without changing the input signals or power supply voltages.

  17. Gas-phase synthesis of the benzyl radical (C(6)H(5)CH(2)).

    Science.gov (United States)

    Dangi, Beni B; Parker, Dorian S N; Yang, Tao; Kaiser, Ralf I; Mebel, Alexander M

    2014-04-25

    Dicarbon (C2 ), the simplest bare carbon molecule, is ubiquitous in the interstellar medium and in combustion flames. A gas-phase synthesis is presented of the benzyl radical (C6 H5 CH2 ) by the crossed molecular beam reaction of dicarbon, C2 (X(1) Σg (+) , a(3) Πu ), with 2-methyl-1,3-butadiene (isoprene; C5 H8 ; X(1) A') accessing the triplet and singlet C7 H8 potential energy surfaces (PESs) under single collision conditions. The experimental data combined with ab initio and statistical calculations reveal the underlying reaction mechanism and chemical dynamics. On the singlet and triplet surfaces, the reactions involve indirect scattering dynamics and are initiated by the barrierless addition of dicarbon to the carbon-carbon double bond of the 2-methyl-1,3-butadiene molecule. These initial addition complexes rearrange via multiple isomerization steps, leading eventually to the formation of C7 H7 radical species through atomic hydrogen elimination. The benzyl radical (C6 H5 CH2 ), the thermodynamically most stable C7 H7 isomer, is determined as the major product.

  18. 40 CFR 721.5560 - Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz[c...

    Science.gov (United States)

    2010-07-01

    ... (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6-oxide. 721.5560 Section 721... Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6... identified as formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with...

  19. The IGU Knowledge Centre

    NARCIS (Netherlands)

    Huizing, Bernardus

    2005-01-01

    This article describes an innovative service for members of the International Gas Union - IGU. The IGU Knowledge Centre provides members with relevant information and data. In this article is described why, how and where.

  20. CENTRE FOR GEOMETRICAL METROLOGY

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    The objective of this Annual Report is to give a general introduction to CGM as well as to give an account of the tasks carried out using the facilities of CGM's Instrument Centre during 1998 and 1999....

  1. Virtual particle therapy centre

    CERN Multimedia

    2015-01-01

    Particle therapy is an advanced technique of cancer radiation therapy, using protons or other ions to target the cancerous mass. This advanced technique requires a multi-disciplinary team working in a specialised centre. 3D animation: Nymus3D

  2. The Bruce Energy Centre

    International Nuclear Information System (INIS)

    The Bruce Energy Centre Development Corporation is a joint venture of the Ontario Energy Corporation and 6 private companies formed to market surplus steam from the Bruce Nuclear Power Development. The corporation will also sell or lease land near Bruce NPD. The Bruce Energy Centre has an energy output of 900 BTU per day per dollar invested. Potential customers include greenhouse operators, aquaculturalists, food and beverage manufacturers, and traditional manufacturers

  3. High Power, Room Temperature Terahertz Emitters Based on Dopant Transitions in 6H-Silicon Carbide

    Institute of Scientific and Technical Information of China (English)

    James Kolodzey; Guang-Chi Xuan; Peng-Cheng Lv; Nathan Sustersic; Xin Ma

    2014-01-01

    Electrically pumped high power terahertz (THz) emitters that operated above room temperature in a pulse mode were fabricated from nitrogen-doped n-type 6H-SiC. The emission spectra had peaks centered on 5 THz and 12 THz (20 meV and 50 meV) that were attributed to radiative transitions of excitons bound to nitrogen donor impurities. Due to the relatively deep binding energies of the nitrogen donors, above 100 meV, and the high thermal conductivity of the SiC substrates, the THz output power and operating temperature were significantly higher than previous dopant based emitters. With peak applied currents of a few amperes, and a top surface area of 1 mm2, the device emitted up to 0.5 mW at liquid nitrogen temperature (77 K), and tens of microwatts up to 333 K. This result is the highest temperature of THz emission reported from impurity-based emitters.

  4. Band alignment at organic-inorganic heterojunctions between P3HT and n-type 6H-SiC.

    Science.gov (United States)

    Dietmueller, Roland; Nesswetter, Helmut; Schoell, Sebastian J; Sharp, Ian D; Stutzmann, Martin

    2011-11-01

    The exact band alignment at organic/inorganic semiconductor heterojunctions is influenced by a variety of properties and is difficult to predict. For organic/inorganic bilayer heterojunctions made of poly(3-hexylthiophene) (P3HT) and n-type 6H-SiC, the band alignment is determined via current-voltage measurements. For this purpose, a model equivalent circuit, combining thermionic emission and space-charge-limited current effects, is proposed which describes the behavior of the heterojunction very well. From the fitting parameters, an interface barrier height of 1.1 eV between the lowest unoccupied molecular orbital (LUMO) of P3HT and the conduction band (CB) of 6H-SiC is determined. In addition, from the maximum open circuit voltage of 6H-SiC/P3HT diodes, a difference of 0.9 eV between the highest occupied molecular orbital (HOMO) of P3HT and the CB of 6H-SiC is deduced. These two values determine the alignment of the energy bands of 6H-SiC relative to the HOMO and LUMO of P3HT. The 6H-SiC/P3HT bilayer heterojunction exhibits an open circuit voltage of ~0.5 V at room temperature, which makes such a materials system a potential candidate for bulk heterojunction hybrid solar cells with 6H-SiC nanoparticles. PMID:21936559

  5. Electron stimulated desorption of cations from C sub 6 H sub 6 and C sub 6 H sub 1 sub 2 molecules adsorbed on Pt(1 1 1) and Ar spacer layer

    CERN Document Server

    Kawanowa, H; Hanatani, K; Gotoh, Y; Souda, R

    2003-01-01

    Mechanisms of electron stimulated cation desorption have been investigated for adsorbed C sub 6 H sub 6 and C sub 6 H sub 1 sub 2 molecules on the Pt(1 1 1) surface and the Ar spacer layer formed on it. The ion yields from the molecules adsorbed on the Ar spacer layer are highly enhanced at the smallest coverage and decay steeply with increasing coverage. No such enhancement was observed when they are adsorbed directly on the Pt(1 1 1) substrate. This behavior is explained in terms of the Coulombic repulsion of cations confined in nanoclusters, together with the delocalization of valence holes on the Pt(1 1 1) substrate as well as in the multilayer hydrocarbons. The holes in the C sub 6 H sub 6 molecule are more delocalized than those in the C sub 6 H sub 1 sub 2 molecule due to the overlap of pi orbitals.

  6. ZStudies on the Phase Equilibrium of BaCl2-C6H12O6-H2O/(H2O and CH3CH2OH) at 30 ℃%BaCl2-C6H12O6-H2O/(H2O+CH3CH2OH)体系在30 ℃时的相平衡研究

    Institute of Scientific and Technical Information of China (English)

    王飞利; 胡道道; 李淑妮; 朱西燕; 李君; 唐宗薰

    2001-01-01

    用等温溶解度法研究了BaCl2-C6H12O6-H2O/(H2O+CH3CH2OH)体系在30 ℃时的相平衡, 发现在体系中有一未见文献报道的不一致溶解的化合物BaCl2*2C6H12O6*2H2O生成. 研究结果为肌醇生产除杂质工艺提供了理论依据.

  7. Normal coordinate analysis and quantum chemical study of tris(-fluorophenyl)antimony di(-phenylglycinate) [(-FC6H4)3Sb(O2CCH2NHC6H5)2

    Indian Academy of Sciences (India)

    Tanveer Hasan; P K Singh; K Singhal; P Raj; Neeraj Misra

    2007-10-01

    A complete normal coordinate analysis was performed by two different methods: a classical Wilson's G-F matrix method and the semi-empirical molecular orbital PM3 method, for a five coordinate tris(-fluorophenyl)antimony di( -phenylglycinate) [(-FC6H4)3Sb(O2CCH2NHC6H5)2], known to be an in vitro antitumour molecule.

  8. The ideal Atomic Centre

    International Nuclear Information System (INIS)

    The author presents considerations which should prove to be of interest to all those who have to design, to construct and to operate a nuclear research centre. A large number of the ideas presented can also be applied to non-nuclear scientific research centres. In his report the author reviews: various problems with which the constructor is faced: ground-plan, infrastructure, buildings and the large units of scientific equipment in the centre, and those problems facing the director: maintenance, production, supplies, security. The author stresses the relationship which ought to exist between the research workers and the management. With this aim in view he proposes the creation of National School for Administration in Research which would train administrative executives for public or private organisations; they would be specialised in the fields of fundamental or applied research. (author)

  9. Synthesis of two pentaarylated [ 60 ]fullerene derivatives Ar5C60-H (Ar = p-MeC6H4, m-MeC6H4) and their novel electrochemical properties

    Institute of Scientific and Technical Information of China (English)

    SONG, Li-Cheng(宋礼成); LIU, Peng-Chong(刘鹏蹟); HU, Qing-Mei(胡青眉); ZANELLO, Piero; FONTANI, Marco

    2000-01-01

    Through one pot reaction of C60 with organocopper/magnesium reagent ( p -MeC6 H4 )2 CuMgBr or ( m- MeC6 H4 )2-CuMgBr prepared from CuBr· Me2S and p-MeC6H4MgBr or m-MeC6H4MgBr and subsequent quenching with aqueous NHeCl, two pentaarylated [60] fullerene derivatives (p-MeC6H4)5C60H (1) and (m-MeC6H4)5C60H (2) have been synthesized in 94% and 96% yields, respectively. While known compound 1 prepared via this improved method is unambiguously identified, new compound 2 is fully characterized by elemental analysis, IR, UV-vis, 1H NMR and 13C NMR spectroscopies. Additionally, electrochemical study shows that the two [60] fullerene derivatives 1 and 2 in dichloromethane solution display two sequential one-electron reductions which are shifted by about 0.4 V towards more negative potential values with respect to free C60. Such remarkable cathodic shift is attributed to the multiple breakage of the double-bond conjugation within the fullerene core.

  10. Lidar Calibration Centre

    Science.gov (United States)

    Pappalardo, Gelsomina; Freudenthaler, Volker; Nicolae, Doina; Mona, Lucia; Belegante, Livio; D'Amico, Giuseppe

    2016-06-01

    This paper presents the newly established Lidar Calibration Centre, a distributed infrastructure in Europe, whose goal is to offer services for complete characterization and calibration of lidars and ceilometers. Mobile reference lidars, laboratories for testing and characterization of optics and electronics, facilities for inspection and debugging of instruments, as well as for training in good practices are open to users from the scientific community, operational services and private sector. The Lidar Calibration Centre offers support for trans-national access through the EC HORIZON2020 project ACTRIS-2.

  11. Quantum dot spectroscopy

    DEFF Research Database (Denmark)

    Leosson, Kristjan

    Semiconductor quantum dots ("solid-state atoms") are promising candidates for quantum computers and future electronic and optoelectronic devices. Quantum dots are zero-dimensional electronic systems and therefore have discrete energy levels, similar to atoms or molecules. The size distribution...

  12. Quantum Dots: Theory

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

  13. Ultrasmall silicon quantum dots

    NARCIS (Netherlands)

    Zwanenburg, F.A.; Van Loon, A.A.; Steele, G.A.; Rijmenam, C.E.W.M.; Balder, T.; Fang, Y.; Lieber, C.M.; Kouwenhoven, L.P.

    2009-01-01

    We report the realization of extremely small single quantum dots in p-type silicon nanowires, defined by Schottky tunnel barriers with Ni and NiSi contacts. Despite their ultrasmall size the NiSi–Si–NiSi nanowire quantum dots readily allow spectroscopy of at least ten consecutive holes, and addition

  14. International research centre launched

    International Nuclear Information System (INIS)

    Full text: The first scientific research and educational institution to be set up on a completely international basis was officially inaugurated in Trieste on 5 October 1964 by the Director General of IAEA, Dr. Sigvard Eklund, when he opened the first seminar of the International Centre for Theoretical Physics. As evidence of the international nature of the institution he noted that the scientists who would work and teach there during the first year represented sixteen different countries. By the end of 1964, the Centre building was nearing completion and three of the five floors were occupied. A successful symposium had been held on the subject of plasma physics, and a score of professors and fellows were at work, from Bulgaria, Czechoslovakia, Greece, India, Japan, Jordan, the Netherlands, Norway, Pakistan, Poland, the United Kingdom, and the United States. A dozen scientific papers had been issued as preprints. The main purpose of the Centre is to foster the advancement of theoretical physics through training and research; at first the chief subject will be high-energy and elementary particle physics. Plasma physics, low energy physics and solid-state physics will also be dealt with. Special attention is paid to the needs of the developing countries. Of the 25 fellows selected for the academic year 1964-65, more than half are from South America, Africa and Asia. In conjunction with the Research Centre, there is an Advanced School for theoretical Physics to provide graduate training for fellows who need such preparation before they embark upon research. The Centre works under the guidance of a Scientific Council comprising the president, Prof. M. Sandoval-Vallarta (Nuclear Energy Commission of Mexico); Prof. A. Abragam (Saclay, France); Prof. R. Oppenheimer (Institute for Advanced Study, Princeton, USA); Dr. V. Soloviev (Dubna, USSR); Prof V.F. Weiskopf (Director General, CERN) ; Prof Abdus Salam (Imperial College, London) ; Prof. P. Budini (University of Trieste

  15. Studies of the pressure-induced phase transition of C sub 3 N sub 6 H sub 6

    CERN Document Server

    Ma Hong An; Cui Qi Liang; Pan Yue Wu; Zhu Pin Wen; Guo Wei; Chen Li Xue; Ren Guo Zheng; Zou Guang Tian; LiuJing

    2002-01-01

    In situ high pressure energy dispersive X-ray diffraction experiments have been carried out on C sub 3 N sub 6 H sub 6 by using diamond anvil cell (DAC) device with synchrotron radiation source. Two structural phase transitions of C sub 3 N sub 6 H sub 6 have been observed within 14.7 GPa pressure range, from monoclinic to triclinic structure at 1.3 GPa and from triclinic to orthorhombic structure at 8.2 GPa, respectively

  16. Long-Term Characterization of 6H-SiC Transistor Integrated Circuit Technology Operating at 500 C

    Science.gov (United States)

    Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith Roger D.; Ferrier, Terry L.; Krasowski, Michael J.; Prokop, Norman F.

    2008-01-01

    NASA has been developing very high temperature semiconductor integrated circuits for use in the hot sections of aircraft engines and for Venus exploration. This paper reports on long-term 500 C electrical operation of prototype 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). As of this writing, some devices have surpassed 4000 hours of continuous 500 C electrical operation in oxidizing air atmosphere with minimal change in relevant electrical parameters.

  17. Quantum dot density studies for quantum dot intermediate band solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Thomassen, Sedsel Fretheim; Zhou, Dayong; Vitelli, Stefano; Mayani, Maryam Gholami; Fimland, Bjoern-Ove; Reenaas, Turid Worren

    2010-07-01

    Quantum dots (QDs) have been an active area of research for many years and have been implemented in several applications, such as lasers and detectors. During the last years, some attempts have been made to increase the absorption and efficiency of solar cells by inserting QDs into the intrinsic region of pin solar cells. So far, these attempts have been successful in increasing the absorption, but not the cell efficiency. There are probably several reasons for this lack of efficiency increase, but we believe that one important reason is the low density of the implemented QDs. In this work, samples of single layer InAs QDs on n-GaAs(001) substrates have been grown by molecular beam epitaxy (MBE) and we have performed a systematic study of how deposition parameters affect the QD density. The aim is to achieve densities > 1011 cm-2. The nominal substrate temperature (360 - 500 deg. C), the InAs growth rate (0.085 - 1 ML/s) and thickness (2.0 - 2.8 ML) have been varied in a systematic way for two different deposition methods of InAs, i.e. continuous deposition or deposition with interruptions. In addition, we have for the continuous growth samples also varied the As-flux (0.5 - 6 centre dot10-6 torr). Scanning electron microscopy (SEM) has been the main characterization method to determine quantum dot sizes and densities, and atomic force microscopy (AFM) has been used for evaluation of the quantum dot heights. We find that the QD density increases with reduced growth temperature and that it is higher for samples grown continuously than for samples grown with growth interruptions. The homogeneity is also strongly affected by temperature, InAs deposition method and the As-flux. We have observed QD densities as high as 2.5 centre dot1011 cm-2 for the samples grown at the lowest growth temperatures. (Author)

  18. 6H-Indolo[2,3-b]quinoxalines: DNA and protein interacting scaffold for pharmacological activities.

    Science.gov (United States)

    Moorthy, N S Hari Narayana; Manivannan, E; Karthikeyan, C; Trivedi, Piyush

    2013-08-01

    6H-Indolo[2,3-b]quinoxaline, a planar fused heterocyclic compound exhibits a wide variety of pharmacological activities. The mechanism of pharmacological action exerted by these compounds is predominantly DNA intercalation. The thermal stability of the intercalated complex (DNA and 6H-indolo[2,3-b]quinoxaline derivatives) is an important parameter for the elucidation of anticancer, antiviral and other activities. This thermal stability of the 6H-indolo[2,3- b]quinoxaline-DNA complex depends on the type of substituents and side chains attached to the 6H-indolo[2,3- b]quinoxaline nucleus and also the orientation of the side chain towards the GC rich minor groove of the DNA. Highly active 6H-indolo[2,3-b]quinoxaline derivatives such as NCA0424, B-220 and 9-OH-B-220 have shown good binding affinity to DNA as evident from high thermal stability of compound-DNA complex. Interestingly, these compounds possessed poor inhibitory activity on topoisomerase II enzyme but have significant MDR modulating activity. This review establishes '6H-indolo[2,3-b]quinoxaline' as a valuable template for design and development of novel molecules with different biological activities.

  19. Academic Drug Discovery Centres

    DEFF Research Database (Denmark)

    Kirkegaard, Henriette Schultz; Valentin, Finn

    2014-01-01

    Academic drug discovery centres (ADDCs) are seen as one of the solutions to fill the innovation gap in early drug discovery, which has proven challenging for previous organisational models. Prior studies of ADDCs have identified the need to analyse them from the angle of their economic...

  20. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  1. ATLAS Visitors Centre

    CERN Multimedia

    claudia Marcelloni

    2009-01-01

    ATLAS Visitors Centre has opened its shiny new doors to the public. Officially launched on Monday February 23rd, 2009, the permanent exhibition at Point 1 was conceived as a tour resource for ATLAS guides, and as a way to preserve the public’s opportunity to get a close-up look at the experiment in action when the cavern is sealed.

  2. Search experiment for neutron-rich Λ hypernuclei Λ6H at J-PARC

    International Nuclear Information System (INIS)

    The authors adopted 6Li(Π-, K+) reaction under the momentum of 1.2 GeV/c at J-PARC hadron experimental facility K1.8 beam line, and conducted the generation experiment of neutron-rich hypernuclei Λ6H (J-PARC E10 experiment). However, the authors could not reach the discovery of the peak indicating hypernuclei in the vicinity of bound threshold, Λ4H + 2n (580.17 MeV), and obtained the formation cross-section of 1.2 nb/sr at 90% of confidence level as the upper limit smaller than the expected 10 nb/sr. This is the value smaller by one order than the expected one from the previous theories and experiments, resulted in the need of the reconstruction of a theoretical model including the core nucleus 5H. On the other hand, from the form of continuous state of the defective mass of Λ and Σ, the magnitude of the optical potential that Σ particles in nuclei sense was given. (A.O.)

  3. Vanadium-Doped Semi-Insulating 6H-SiC for Microwave Power Device Applications

    Institute of Scientific and Technical Information of China (English)

    Li'na Ning; Zhihong Feng; Yingmin Wang; Kai Zhang; Zhen Feng; Xiangang Xu

    2009-01-01

    Two-inch semi-insulating SiC bulk crystals with resistivity higher than 1×106 Ωcm were achieved by vanadium doping during sublimation. Secondary-ion-mass-spectrometry (SIMS) was employed to determine the concen-tration of impurities in the crystals, such as B, Al, V and N. These results indicated that the concentration of nitrogen and aluminum kept on decreasing and the concentration of B and V was almost constant during the whole growth. An inner crucible was used to control the exhausting of vanadium, which made the uniformity of the high resistivity (1×106 Ωcm) in the wafer up to 80%. High-performance AlGaN/GaN high-electron-mobility-transistor (HEMT) materials and devices were grown and fabricated on semi-insulating 6H-SiC sub-strates. The two-dimensional electron gas (2DEG) mobility at room-temperature was 1795 cm2/V·s. The charge carrier concentration of the substrate determined by capacitance-voltage (C-V) test was 7.3 × 1015 cm-3. The device with a gate width of 1 mm exhibits a maximum output power of 5.5 W at 8 GHz, which proves the semi-insulating property of the substrates indirectly.

  4. Defect dynamics in P+ implanted 6H-SiC studied by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    We study P+-implanted 6H-SiC samples by means of a variable energy slow positron beam. In as-grown samples we observe a slow fall of the annihilation S-parameter from the surface to the bulk value, indicating a long diffusion length, i.e. absence of positron-trapping defects. This result is also confirmed by positron-lifetime measurements yielding essentially a single-component lifetime of 148 ps. In the implanted samples we detect a wide flat region of slightly risen defectiveness. However, we note that, in order to reproduce reasonably well the depth of the damaged layer, one has to assume the presence of strong electric fields in the implanted region. With annealing, S-curves show a rising maximum, moving towards surface - probably, in as-implanted samples the defects are decorated by P+ ions and do not trap positrons in effective way. After the highest temperature annealing a highly defected region extends for the first 50 nm depth. We perform also atomic force microscopy to monitor the evolution of the surface defects. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Functionalization of (0001) 6H-SiC with organic silanes

    Energy Technology Data Exchange (ETDEWEB)

    Schoell, Sebastian; Hoeb, Marco; Sharp, Ian; Stutzmann, Martin; Eickhoff, Martin; Brandt, Martin S. [Walter Schottky Institut, Technische Universitaet Muenchen, Garching (Germany)

    2008-07-01

    Due to its extraordinary physical properties and chemical stability SiC is a promising material for biosensor applications. The affinity of SiC to form OH-terminated surfaces by wet chemical treatments is exploited to generate functional layers via silanization with organic molecules on SiC. In particular, wet chemically processed layers of ODTMS and APDEMS on n-type (0001) 6H-SiC were investigated. The structural and chemical properties of these layers were studied by contact angle measurements, atomic force microscopy (AFM), thermal desorption spectroscopy (TDS), and X-ray photoelectron spectroscopy (XPS). The organic layers are smooth and change their wettablity depending on the molecules used. Desorption temperatures in the range of 550 C indicate covalent bonding of the organic molecules to the SiC surface. Starting from monolayers with amine functional groups, the possibility of attaching complex molecules was demonstrated by immobilizing proteins on micropatterned organic layers followed by direct imaging via fluorescence microscopy.

  6. Large area graphene growth on 6H-SiC(0001)

    Science.gov (United States)

    Johansson, L. I.; Virojanadara, C.; Syväjärvi, M.; Yakimova, R.; Zakharov, A. A.; Balasubramanian, T.

    2009-03-01

    Large area graphene growth on commercial Si-face on-axis 6H-SiC(0001) is demonstrated in this work. Samples were produced in a prototype of an inductively heated furnace. The growth was carried out in strongly isothermal conditions at a temperature of 2000 C and at an ambient argon pressure of 1 atm. The quality and thickness of the graphene layers grown, using this ex situ method, were investigated using PES, ARPES), LEED as well as LEEM, PEEM micro-LEED and micro-PES at specifically defined small areas. Our results show that single layer graphene is formed over quite large areas on the sample but that two different domains can exist on some parts. A comparison with an in situ graphene sample, prepared by resistive heating to 1275 C, was made. The results then obtained were similar to earlier findings [1-2] and showed that the size of the graphene flakes were very small compared to those obtained on the samples prepared with our ex situ method. [3pt] [1]. T. Ohta, F. El Gabaly, A. Bostwick, J.L. McChesney, K.V. Emtsev, A.K. Schmid, Th. Seyller, K. Horn, E. Rotenberg, New. J. Phys. 10 023034 (2008).[0pt] [2]. J.B. Hannon and R. M. Tromp, Phys. Rev. B 77 241404 (2008).

  7. FT-IR study on interactions between medroxyprogesterone acetate and solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems

    Science.gov (United States)

    Shi, Jie-hua; Fan, Chun-hui

    2012-09-01

    The intermolecular interactions between medroxyprogesterone acetate (MPA) and CHCl3 and CCl4 solvent in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems have been studied by Fourier transform infrared spectroscopy (FT-IR). The experimental results showed that there are hydrogen bonding interactions between oxygen atoms of all carbonyl groups in MPA and hydrogen atom of CHCl3 so as to form 1:3 complex of MPA with CHCl3 and produce three new absorption bands at 1728.9-1736.1, 1712.7-1717.4 and 1661.9-1673.8 cm-1, respectively. And, 1:1 complex of MPA with CCl4 is formed in CCl4/cyclo-C6H12 binary solvent as a result of hydrogen bonding interaction between C3 carbonyl group and empty d-orbital in chlorine atom of CCl4 leading to producing new absorption band at 1673.2-1674.2 cm-1. However, all free carbonyl and associated carbonyl stretching vibrations of MPA in CHCl3/cyclo-C6H12 and CCl4/cyclo-C6H12 binary solvent systems shift to lower wavenumbers with the increasing of volume fraction of CHCl3 and CCl4 in binary solvent systems owing to the dipole-dipole interaction and the dipole-induced dipole interaction between MPA and solvents.

  8. Mechanical Properties and Defect Evolution of Kr-Implanted 6H-SiC

    Institute of Scientific and Technical Information of China (English)

    XU Chao-Liang; ZHANG Chong-Hong; ZHANG Yong; ZHANG Li-Qing; YANG Yi-Tao; JIA Xiu-Jun; LIU Xiang-Bing; HUANG Ping; WANG Rong-Shan

    2011-01-01

    Specimens of silicon carbide (6H-SiC) were irradiated with 5 MeV Kr ions (84Kr19+) for three fluences of 5× 1013,2×1014 and 1 ×1015 ions/cm2,and subsequently annealed at room temperature,500℃,700℃ and 1000℃,respectively.The strain of the specimens was investigated with high resolution XRD and different defect evolution processes are revealed.An interpretation of the defect evolution and migration is given to explain the strain variation.The mechanical properties of the specimens were studied by using a nano-indentation technique in continuous stiffness measurement (CSM) mode with a diamond Berkovich indenter.For specimens irradiated with fluences of 5× 1013 or 2× 1014 ions/cm2,hardness values exceed that of un-implanted SiC.However,hardness sharply degrades for specimens irradiated with the highest fluence of 1 ×1015 ions/cm2.The specimens with fluences of 5× 1013 and 2× 1014 ions/cm2 and subsequently annealed at 700℃ and 500℃,respectively,show the maximum hardness value.SiC is very suitable for use in advanced nuclear reactors and radioactive nuclear waste disposal due to its high-temperature stability,chemical inertness,good mechanical properties and small neutron capture cross sections.[1,2] The production of lattice damage and helium/heavier inert gas atoms due to irradiation and nuclear transmutation have been a serious concern for applications of silicon carbide in these environments.%Specimens of silicon carbide (6H-SiC) were irradiated with 5MeV Kr ions (84Kr19+) for three fluences of 5×1013, 2×1014 and 1×1015 ions/cm2, and subsequently annealed at room temperature, 500℃, 700℃ and 1000℃, respectively. The strain of the specimens was investigated with high resolution XRD and different defect evolution processes are revealed. An interpretation of the defect evolution and migration is given to explain the strain variation. The mechanical properties of the specimens were studied by using a nano-indentation technique in continuous

  9. The electron spin resonance study of heavily nitrogen doped 6H SiC crystals

    Energy Technology Data Exchange (ETDEWEB)

    Savchenko, D. V., E-mail: dariyasavchenko@gmail.com [Institute of Physics AS CR, Prague 182 21, Czech Republic and V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028 (Ukraine)

    2015-01-28

    The magnetic and electronic properties of heavily doped n-type 6H SiC samples with a nitrogen concentration of 10{sup 19} and 4 × 10{sup 19 }cm{sup −3} were studied with electron spin resonance (ESR) at 5–150 K. The observed ESR line with a Dysonian lineshape was attributed to the conduction electrons (CE). The CE ESR (CESR) line was fitted by Lorentzian (insulating phase) (T < 40 K) and by Dysonian lineshape (metallic phase) above 40 K, demonstrating that Mott insulator-metal (IM) transition takes place at ∼40 K, accompanied by significant change in the microwave conductivity. The temperature dependence of CESR linewidth follows the linear Korringa law below 40 K, caused by the coupling of the localized electrons (LE) and CE, and is described by the exponential law above 40 K related to the direct relaxation of the LE magnetic moments via excited levels driven by the exchange interaction of LE with CE. The g-factor of the CESR line (g{sub ‖} = 2.0047(3), g{sub ⊥} = 2.0034(3)) is governed by the coupling of the LE of nitrogen donors at hexagonal and quasi-cubic sites with the CE. The sharp drop in CESR line intensity (25–30 K) was explained by the formation of antiferromagnetic ordering in the spin system close to the IM transition. The second broad ESR line overlapped with CESR signal (5–25 K) was attributed to the exchange line caused by the hopping motion of electrons between occupied and non-occupied positions of the nitrogen donors. Two mechanisms of conduction, hopping and band conduction, were distinguished in the range of T = 10–25 K and T > 50 K, respectively.

  10. Elderly Care Centre

    Science.gov (United States)

    Wagiman, Aliani; Haja Bava Mohidin, Hazrina; Ismail, Alice Sabrina

    2016-02-01

    The demand for elderly centre has increased tremendously abreast with the world demographic change as the number of senior citizens rose in the 21st century. This has become one of the most crucial problems of today's era. As the world progress into modernity, more and more people are occupied with daily work causing the senior citizens to lose the care that they actually need. This paper seeks to elucidate the best possible design of an elderly care centre with new approach in order to provide the best service for them by analysing their needs and suitable activities that could elevate their quality of life. All these findings will then be incorporated into design solutions so as to enhance the living environment for the elderly especially in Malaysian context.

  11. Synthesis and Characterization of Diorganotin Compounds {[R2Sn(ON=CHC6H5)]2O}2 and Crystal Structure of {[(C6H5CH2)2Sn(ON = CHC6H5)]2O}2

    Institute of Scientific and Technical Information of China (English)

    YIN,Han-Dong(尹汉东); XUE,Sheng-Cai(薛绳才); WANG,Qi-Bao(王其宝)

    2004-01-01

    Diorganotin compounds {[R2Sn(ON=CHC6H5)]2O}2 [R=C6H5CH2 (1), 2-FC6H4CH2 (2), 4-FC6H4CH2 (3),2-C1C6H4CH2 (4), 4-C1C6H4CH2 (5)] were synthesized by the reaction of R2SnO with HON=CHC6H5 in 1: 1 molar ratio in refluxing anhydrous benzene or toluene. They were characterized by elemental analysis, IR, 1H NMR and 119sn NMR spectroscopy. And two sets of 119sn chemical shifts were observed in the 119Sn NMR spectra of these compounds, indicating the presence of two types of environment around the tin atoms. The crystal structure of compound 1 was determined by X-ray single crystal diffraction analysis. The results showed that the crystal of compound 1 belongs to a monoclinic system with space group P21/c and unit cell dimensions: a= 1.0718(9) nm, b=1.9666(17) nm, c=2.0480(17) nm, β=96.4371(14)°, Dc= 1.450 g/cm3, Z=2, F(000)= 1888, V=4.290(6) nm3, μ= 1.206 mm -1, R1 =0.0405, wR2= 0.0786. The compound 1 belongs to centrosymmetric dimer structure mode with a four-membered central endo-cyclic Sn2O2 unit in which the bridging oxygen atoms are tri-coordinated. Each bridging oxygen atom also connects with an exo-cyclic tin atom. The endo- and exo-cyclic tin atoms are both five-coordinated, and have coordination geometry of distorted trigonal bipyramid.

  12. Graphene quantum dots

    CERN Document Server

    Güçlü, Alev Devrim; Korkusinski, Marek; Hawrylak, Pawel

    2014-01-01

    This book reflects the current status of theoretical and experimental research of graphene based nanostructures, in particular quantum dots, at a level accessible to young researchers, graduate students, experimentalists and theorists. It presents the current state of research of graphene quantum dots, a single or few monolayer thick islands of graphene. It introduces the reader to the electronic and optical properties of graphite, intercalated graphite and graphene, including Dirac fermions, Berry's phase associated with sublattices and valley degeneracy, covers single particle properties of

  13. Tele-centres in Ghana

    DEFF Research Database (Denmark)

    Falch, Morten

    2004-01-01

    Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access.......Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access....

  14. Depth profiling of oxide-trapped charges in 6H-SiC MOS structures by slant etching method

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, Kazunari; Takahashi, Yoshihiro; Ohnishi, Kazunori [Nihon Univ., Tokyo (Japan). Coll. of Science and Technology; Yoshikawa, Masahito; Ohshima, Takeshi; Itoh, Hisayoshi; Nashiyama, Isamu

    1997-03-01

    In this paper, we propose a method to evaluate the depth profile of trapped charges in an oxide layer on SiC. Using this method, 6H-SiC MOS structures with different oxide thickness were fabricated on the same substrate under the same oxidation condition, and the depth profile of oxide-trapped charges before and after {sup 60}Co-gamma ray irradiation were obtained. It is found, from the depth profiling, that the trapping mechanism of electrons and holes in the oxide strongly depends on the bias polarity during irradiation, and these charges are trapped near 6H-SiC/SiO{sub 2} interface. We believe that this method is very useful for estimation of the oxide-trapped charges in 6H-SiC MOS structures. (author)

  15. Device-relevant defect centers and minority carrier lifetime in 3C-, 4H- and 6H-SiC

    OpenAIRE

    Reshanov, Sergey

    2005-01-01

    1. Erbium in SiC Two Er-related centers termed Er(p)1/Er(p)2 are observed in the DLTS spectra of p-type 4H- and 6H-SiC. The following values of thermal ionization energy were found out for dominating Er-related defect Er(p)1: Eth(Er(p)1) = 0,58eV in 4H-SiC, Eth(Er(p)1) = 0,62eV in 6H-SiC. These centers are donor-like. Hole capturing correspond to multiphonon capture mechanism. Capture barrier for holes Ec(Er(p)1) = 0.1eV for both 4H- and 6H-SiC. The observed Er-related centers can be presumab...

  16. 3-Acetyl-2-fluoro-6H-benzo[c]chromen-6-one

    Directory of Open Access Journals (Sweden)

    Yoshinobu Ishikawa

    2014-04-01

    Full Text Available The title compound, C15H9FO3, was obtained in a one-pot synthesis by Suzuki–Miyaura cross-coupling and nucleophilic substitution reaction of 4′-chloro-2′,5′-difluoroacetophenone with o-(methoxycarbonylphenylboronic acid. The asymmetric unit contains two crystallographically independent molecules related by a non-crystallographic inversion centre. There are face-to-face stacking interactions between the aromatic rings of the benzoate and acetophenone units of the symmetry-independent molecules [centroid–centroid distances = 3.870 (3 and 3.986 (3 Å]. In the crystal, molecules are further assembled via stacking interactions along the a-axis direction. One of the molecules interacts with its inversion equivalent [centroid–centroid distance between the aromatic rings of the benzoate and acetophenone units = 3.932 (3 Å], and the other interacts with its twofold axis equivalent [centroid–centroid distance between the aromatic rings of acetophenone units = 3.634 (3 Å].

  17. Treatment Outcomes of Patients Placed on Treatment Under Directly Observed Therapy Short-Course (Dots)

    OpenAIRE

    Kaur Gurpreet; Goel N; Kumar Dinesh; Janmeja A; Swami H; Kalia Meenu

    2008-01-01

    Background : Tuberculosis continues to be a pressing health problem in India. The Revised National Tuberculosis Programme (RNTCP), an application of Directly Observed Treatment Short-course (DOTS) in India, launched in 1997 needs contin-uous evaluation. Objective : To study the outcomes of treatment among the patients put on DOTS under RNTCP in Chandigarh, UT. Material & Methods : A Longitudi-nal study was conducted during 2004-2005 in 13 Microscopic centres (MC′s) spread over...

  18. Binding Energies of Negatively Charged Donors in a Gaussian Potential Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang

    2005-01-01

    @@ We investigate a negatively charged donor centre (D-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are carried out by using the method of numerical diagonalization of Hamiltonian within the effective-mass approximation. The dependence of the ground state of the negatively charged donor on the dot size and the potential depth is studied. The same calculations performed with the parabolic approximation of the Gaussian potential lead to the results that are qualitatively and quantitatively different.

  19. Ball-milling-induced polytypic transformation of 6H-SiC→3C-SiC

    Institute of Scientific and Technical Information of China (English)

    杨晓云; 石广元; 黄和鸾; 吴玉琨

    1999-01-01

    The results of X-ray diffraction (XRD) and high resolution electron microscopy (HREM) show that ball milling at room temperature can induce the polytypic transformation of 6H-SiC→3C-SiC. HREM study reveals that a large number of partial dislocations which play an important role in the transformation can be introduced into SiC crystals during BM by the instant and repeated collisions between balls and powder. The phase transformation follows the route: 6H= (3~+,3~-)→(4~+,2~-)→(5~+, 1~- )→(6~+ ,0~- ).

  20. Transition energies and magnetic properties of a neutral donor complex in a Gaussian GaAs quantum dot

    Science.gov (United States)

    Boda, Aalu; Chatterjee, Ashok

    2016-09-01

    The problem of a neutral hydrogenic donor (D0) centre located at the centre of a GaAs quantum dot with Gaussian confinement is studied in the presence of an external magnetic field. The ground and the first excited state energies and the corresponding binding energies are obtained as functions of the potential strength, quantum dot radius and the magnetic field using a variational method. It is suggested that the first excited state of the D0 centre is bound for sufficiently strong confinement potential. The 1 s - 2p- transition energy and the magnetic susceptibilities for the ground and the first excited states are also determined.

  1. Macro-, Micro-, Nano- and Crystal Structures of a Homodinuclear Complex [NH3(CH2)3NH3]2{Na2[(C6H4O2)2](C6H4O2H)2}

    Institute of Scientific and Technical Information of China (English)

    LU,Xiao-Ming; WEI,Chun-Xia; WANG,Zhen; YE,Chao-Hui

    2007-01-01

    A homodinuclear complex (NH3CH2CH2CH2NH3)2{Na2[(C6H4O2)2](C6H4O2H)2} (1) has been synthesized by a solution-based self-assembly route. It crystallized in monoclinic system with space group P21/c. Every sodium ion coordinates in a tetragonal prism fashion with two O atoms of a terminal chelating catecholate ligand and three O atoms from two bridging catecholate ligands. Two neighboring NaO5 tetragonal prisms are edge-shared and centrosymmetric with regard to the inversion center to form a binuclear cluster {Na2[(C6H4O2)2](C6H4OOH)2}4- anion.The complex anions were aligned parallelly by π-π interaction and linked with the protonated 1,3-propylenediamine through hydrogen bonds which were assembled into a multi-lamellar structure with channels. The crystal exhibits rectangular geometry with an interior triangle hollow structure under optical microscopy. And the scanning electron microscopy (SEM) indicates that the wall of the tubes shows multi-lamella morphologies. Further, the transmission electron microscopy (TEM) reveals that the crystal is composed of multi-lamellar nano-tubes with diameters less than 100 nm. The molecular structure of the complex was compared with that of its isomer complex 2.

  2. Electrical and optical characteristics of Au/PbS/n-6H-SiC structures prepared by electrodeposition of PbS thin film on n-type 6H-SiC substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guelen, Y. [Department of Physics, Faculty of Sciences, Ataturk University, 25240 Erzurum (Turkey); Alanyalioglu, M. [Department of Chemistry, Faculty of Sciences, Ataturk University, 25240 Erzurum (Turkey); Ejderha, K. [Department of Physics, Faculty of Sciences and Arts, Bingoel University, Bingoel (Turkey); Nuhoglu, C. [Department of Physics, Faculty of Sciences, Ataturk University, 25240 Erzurum (Turkey); Turut, A., E-mail: aturut@atauni.edu.tr [Department of Physics, Faculty of Sciences, Ataturk University, 25240 Erzurum (Turkey)

    2011-02-10

    Research highlights: > The diffraction profile of the PbS thin film from XRD experiments has been extracted. > An optical energy band gap value of the PbS film was obtained from the optical absorption spectra. > The Au/PbS/n-6H-SiC Schottky diodes have been formed. > The Schottky barrier height increase has been succeeded by the PbS interlayer. - Abstract: To realize Schottky barrier height (SBH) modification in the Au/n-6H-SiC Schottky diodes, lead sulfide (PbS) thin films were grown on n-6H-SiC by electrodeposition method. At first, XRD experiments were performed to investigate the crystal structure of the PbS film electrodeposited on n-6H-SiC. It has been deduced from the diffraction profile that the PbS thin film has a crystal structure more strongly oriented along the [2 0 0] direction. An optical energy band gap value of 1.42 eV for the PbS film was obtained from its optical absorption spectra. Then, we have prepared Au/PbS/n-6H-SiC Schottky barrier diodes (SBDs) with interface layer and reference Au/n-6H-SiC/Ni SBDs. The SBH enhancement has been succeeded by the PbS interlayer, influencing the space charge region of the SiC. The SBH values of 1.03 and 0.97 eV for the samples with and without the interfacial PbS layer were obtained from the forward bias current-voltage (I-V) characteristics. The SBH increase in the Au/PbS/n-6H-SiC SBD with the interfacial PbS layer has been attributed to the fact that the interface states contain a net negative interface charge in metal/n-type semiconductor contact due to the presence of the interfacial PbS layer.

  3. Electrical and optical characteristics of Au/PbS/n-6H-SiC structures prepared by electrodeposition of PbS thin film on n-type 6H-SiC substrate

    International Nuclear Information System (INIS)

    Research highlights: → The diffraction profile of the PbS thin film from XRD experiments has been extracted. → An optical energy band gap value of the PbS film was obtained from the optical absorption spectra. → The Au/PbS/n-6H-SiC Schottky diodes have been formed. → The Schottky barrier height increase has been succeeded by the PbS interlayer. - Abstract: To realize Schottky barrier height (SBH) modification in the Au/n-6H-SiC Schottky diodes, lead sulfide (PbS) thin films were grown on n-6H-SiC by electrodeposition method. At first, XRD experiments were performed to investigate the crystal structure of the PbS film electrodeposited on n-6H-SiC. It has been deduced from the diffraction profile that the PbS thin film has a crystal structure more strongly oriented along the [2 0 0] direction. An optical energy band gap value of 1.42 eV for the PbS film was obtained from its optical absorption spectra. Then, we have prepared Au/PbS/n-6H-SiC Schottky barrier diodes (SBDs) with interface layer and reference Au/n-6H-SiC/Ni SBDs. The SBH enhancement has been succeeded by the PbS interlayer, influencing the space charge region of the SiC. The SBH values of 1.03 and 0.97 eV for the samples with and without the interfacial PbS layer were obtained from the forward bias current-voltage (I-V) characteristics. The SBH increase in the Au/PbS/n-6H-SiC SBD with the interfacial PbS layer has been attributed to the fact that the interface states contain a net negative interface charge in metal/n-type semiconductor contact due to the presence of the interfacial PbS layer.

  4. DGNB certified Healthcare Centres

    DEFF Research Database (Denmark)

    Brunsgaard, Camilla; Larsen, Tine Steen

    2015-01-01

    for sustainability and wants a certification. This research investigates the decision‐making and design process (DMaDP) behind four DGNB certified Healthcare Centres (HCC) in Northern Jutland in Denmark. In general, knowledge about the DMaDP is important. However it is important to know what part DGNB plays...... a dialog about DGNB and energy concept is important even before anyone start sketching. Experiences with the different approaches will be further outlined in the paper.Future research has the intention to collect further knowledge about DGNB and DMaDP in practise. This project was limited to Healthcare...

  5. Centre liikekeskuksen digital signage

    OpenAIRE

    Bincl, Suzana

    2015-01-01

    Opinnäytetyöni tarkastelee digital signagen suunnittelussa huomioitavia tekijöitä ja sen arvoa markkinointikanavana. Työ on toteutettu tilaustyönä Lappeenrantalaiselle mainostoimisto Mediakolmiolle. Työ sisältää teoriaosuuden lisäksi sisältösuunnitelman rakenteilla olevalle Centre liikekeskukselle. Tavoitteena oli luoda liikekeskukselle sen brändiä tukeva digital signage konsepti. Työ ei sisällä valmista tuotetta, vaan se toimii ehdotelmana myöhemmin alkavalle tuotanno...

  6. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    urban planning and design strategieswhich have been practised in most of the larger Danish towns: pedestrian streets, shopping centres, preservation of historic features, waterfronts, concentration of offices, conference and sports facilities, improvement og traffic and transport conditions as well...... as slum clearence and urban renewal. To a certain extent parallels are drawn to international experiences, especially where these are of such a nature that they can be assumed transferred to Danish connctions. Conclusively, the strategies are discussed in the light of the turn of Danish urban planning...

  7. Volumetric Properties of Binary System C6H6-DMF at 293.15 K%二元体系C6H6-DMF在293.15K下的体积性质

    Institute of Scientific and Technical Information of China (English)

    侯海云; 彭三军; 王晓先; 耿信鹏

    2009-01-01

    利用Anton Paar DMA4500振动管密度计, 测量了293.15 K时二元体系C6H6-DMF(苯-N,N-二甲基甲酰胺)溶液的密度, 利用最小二乘法确立了溶液密度与组成的函数关系. 利用密度数据分别计算了二元体系中C6H6和DMF的表观摩尔体积, 并利用非线性最小二乘拟合法, 分别拟合得到了优化的C6H6和DMF的表观摩尔体积和摩尔分数的函数关系, 以及C6H6和DMF的表观摩尔体积和质量分数的函数关系. 通过对函数关系的极限运算得到了C6H6和DMF的标准偏摩尔体积和摩尔体积. 此外, 还计算了不同组分下体系的超额摩尔体积, 数据可用四参数Redlich-Kister方程很好地关联拟合, 得到方程系数及体系的超额摩尔体积极值位置.

  8. Study of metallothionein-quantum dots interactions.

    Science.gov (United States)

    Tmejova, Katerina; Hynek, David; Kopel, Pavel; Krizkova, Sona; Blazkova, Iva; Trnkova, Libuse; Adam, Vojtech; Kizek, Rene

    2014-05-01

    Nanoparticles have gained increasing interest in medical and in vivo applications. Metallothionein (MT) is well known as a maintainer of metal ions balance in intracellular space. This is due to high affinity of this protein to any reactive species including metals and reactive oxygen species. The purpose of this study was to determine the metallothionein-quantum dots interactions that were investigated by spectral and electrochemical techniques. CuS, CdS, PbS, and CdTe quantum dots (QDs) were analysed. The highest intensity was shown for CdTe, than for CdS measured by fluorescence. These results were supported by statistical analysis and considered as significant. Further, these interactions were analysed using gel electrophoresis, where MT aggregates forming after interactions with QDs were detected. Using differential pulse voltammetry Brdicka reaction, QDs and MT were studied. This method allowed us to confirm spectral results and, moreover, to observe the changes in MT structure causing new voltammetric peaks called X and Y, which enhanced with the prolonged time of interaction up to 6 h.

  9. A novel POSS-coated quantum dot for biological application

    OpenAIRE

    Rizvi SB; Yildirimer L; Ghaderi S; Ramesh B; Seifalian AM; Keshtgar M

    2012-01-01

    Sarwat B Rizvi,1 Lara Yildirimer,1 Shirin Ghaderi,1 Bala Ramesh,1 Alexander M Seifalian,1,2 Mo Keshtgar1,21UCL Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London, United Kingdom; 2Royal Free Hampstead NHS Trust Hospital, London, United KingdomAbstract: Quantum dots (QDs) are fluorescent semiconductor nanocrystals that have the potential for major advancements in the field of nanomedicine through their unique photophys...

  10. Quantum dots trace lymphatic drainage from the mouse eye

    Energy Technology Data Exchange (ETDEWEB)

    Tam, Alex L C; Gupta, Neeru; Zhang Zhexue; Yuecel, Yeni H, E-mail: yucely@smh.ca [Department of Ophthalmology and Vision Sciences, University of Toronto, M5T 2S8 (Canada)

    2011-10-21

    Glaucoma is a leading cause of blindness in the world, often associated with elevated eye pressure. Currently, all glaucoma treatments aim to lower eye pressure by improving fluid exit from the eye. We recently reported the presence of lymphatics in the human eye. The lymphatic circulation is known to drain fluid from organ tissues and, as such, lymphatics may also play a role in draining fluid from the eye. We investigated whether lymphatic drainage from the eye is present in mice by visualizing the trajectory of quantum dots once injected into the eye. Whole-body hyperspectral fluorescence imaging was performed in 17 live mice. In vivo imaging was conducted prior to injection, and 5, 20, 40 and 70 min, and 2, 6 and 24 h after injection. A quantum dot signal was observed in the left neck region at 6 h after tracer injection into the eye. Examination of immunofluorescence-labelled sections using confocal microscopy showed the presence of a quantum dot signal in the left submandibular lymph node. This is the first direct evidence of lymphatic drainage from the mouse eye. The use of quantum dots to image this lymphatic pathway in vivo is a novel tool to stimulate new treatments to reduce eye pressure and prevent blindness from glaucoma.

  11. Group 1B organometallic chemistry XXVII. Complex forming reactions of polynuclear arylcopper compounds; Calk-P bond cleavage in 1,2-bis(diphenylphosphino)ethane (Diphos) by (2-Me2NCH2C6H4)4Cu4 and crystal structure of [(C6H5)2PCu.Diphos]2 -C6H6

    NARCIS (Netherlands)

    Koten, G. van; Noltes, J.G.; Spek, A.L.

    1978-01-01

    Molecular weight measurements and microwave titrations indicate that no interaction occurs between tetrameric 2-Me{2}NCH{2}C{6}H{4}Cu (Ar{4}Cu{4}) and the monodentate ligands PPh{3}, CH{3}CN or pyridine. However, the tetrameric structure Ar{4}Cu{4} breaks down upon interaction (1/1 molar ratio ArCu/

  12. [The primary healthcare centres].

    Science.gov (United States)

    Brambilla, Antonio; Maciocco, Gavino

    2014-04-01

    The central attributes of primary care are: first contact (accessibility), longitudinality (person- focused preventive and curative care overtime), patient-oriented comprehensiveness and coordination (including navigation towards secondary and tertiary care). Besides taking care of the needs of the individuals, primary health care teams are also looking at the community, especially when addressing social determinants of health. The rationale for the benefits for primary care for health has been found in: 1) greater access to needed services; 2) better quality of care; 3) a greater focus on prevention; 4) early management of health problems; 5) organizing and delivering high quality care for chronic non-communicable diseases. This paper describes the role of primary healthcare centres in strengthening community primary services and in reducing health inequalities. Furthemore, the experiences of Regional Health Services from Tuscany and Emilia-Romagna are discussed, with a brief overview of the literature. PMID:24770539

  13. Volumetric Properties of Binary System C6H5CH3-DMF at 293.15 K%二元体系C6H5CH3-DMF在293.15 K时的体积性质

    Institute of Scientific and Technical Information of China (English)

    侯海云; 王晓先; 彭三军; 耿信鹏

    2009-01-01

    关系. 通过对函数关系的极限运算得到了C6H5CH3和DMF的极限偏摩尔体积、标准偏摩尔体积和摩尔体积. 还计算了不同组分下体系的超额摩尔体积, 数据可用四参数Redlich-Kister方程关联拟合得到方程系数. 计算关联了C6H5CH3和DMF的超额偏摩尔体积与摩尔分数的关系. 由三参数多项式极限法得到组分的极限超额偏摩尔体积值与Redlich-Kister系数法得到的值在误差范围内一致.

  14. Syntheses, structure and intercalation properties of low-dimensional phenylarsonates, A(HO3AsC6H5)(H2O3AsC6H5) (A = Tl, Na, K and Rb)

    Indian Academy of Sciences (India)

    Bonthu Krishna Kishore Reddy; K Prabhakara Rao; K Vidyasagar

    2006-01-01

    Four new low-dimensional phenylarsonates, A(HO3AsC6H5)(H2O3AsC6H5) (A = Tl(1), Na(2), K(3) and Rb(4)), have been synthesized and characterized by X-ray diffraction, spectroscopic and thermal studies. They crystallize in triclinic unit cells and have approximately planar arrangement of A+ ions, coordinated to oxygen atoms of phenylarsonates, on both sides. Structure of thallium phenylarsonate as determined by single crystal X-ray diffraction, is one-dimensional, whereas those of alkalimetal analogues are two-dimensional. Successful intercalation reactions of compounds 1 and 2 with primary -alkyl amines have been demonstrated.

  15. Quantum dot solar cells

    CERN Document Server

    Wu, Jiang

    2013-01-01

    The third generation of solar cells includes those based on semiconductor quantum dots. This sophisticated technology applies nanotechnology and quantum mechanics theory to enhance the performance of ordinary solar cells. Although a practical application of quantum dot solar cells has yet to be achieved, a large number of theoretical calculations and experimental studies have confirmed the potential for meeting the requirement for ultra-high conversion efficiency. In this book, high-profile scientists have contributed tutorial chapters that outline the methods used in and the results of variou

  16. Experiences of Telebased Information Centres

    DEFF Research Database (Denmark)

    Falch, Morten

    1999-01-01

    Tele-based information community centres or just tele-centres have been seen as the killer application to empower local communities in developed and developing countries to meet the challenges of the information society. This paper will present a number of models for introducing such centres and ...... and discuss the different models and national strategies used for setting up tele-based information in relation to the Ghana experience.......Tele-based information community centres or just tele-centres have been seen as the killer application to empower local communities in developed and developing countries to meet the challenges of the information society. This paper will present a number of models for introducing such centres...

  17. Update on System Coordination Centre

    Energy Technology Data Exchange (ETDEWEB)

    Stangl, W. [Power Pool of Alberta, Calgary, AB (Canada)

    1998-07-01

    The new System Coordination Centre at the Power Pool of Alberta was designed to meet the unique requirements of Alberta`s electric industry under the new regulatory regime. Development of the Centre, key provisions of the energy management system (EMS) are highlighted. The centre will provide an energy management system for the Pool`s system controller function and interface with the Power Pool Administrator`s market functions and the operations of the Transmission Administrator. System controllers are expected to be operating from the new location by the end of 1998. Unique EMS features of the centre include: (1) real-time management of energy market and network operations using diverse SCADA/EMS, (2) inter-control centre protocol used to accommodate the unique participant information requirements, and (3) special custom applications. The Centre is expected to be fully functioning by July 1999. 1 fig.

  18. Synthesis and Crystal Structure of a Hydrogen-bonded Supramolecular Compound [(C6H5N2O)3·Cu1.5]·6H2O

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A hydrogen-bonded supermolecular compound [(C6H5N2O)3·Cu1.5](6H2O was syn- thesized from picolinamide and Cu(NO3)2·6H2O at the presence of sodium pyrophosphate deca- hydrate. It crystallizes in triclinic, space group P with a = 1.05947(8), b = 1.09130(8), c = 1.11456(8) nm, α = 67.8460(10), β = 84.497(1), γ = 74.6210(10)°, C18H27Cu1.5N6O9, Mr = 566.77, V = 1.15077(15) nm3, Z = 2, Dc = 1.636 g/cm3, F(000) = 585, μ = 1.461 mm-1, R1 = 0.0278 and wR2 = 0.0749. In the complex, the Cu(II) ion reveals a distorted tetradentate plane-tetragonal geometry. The structure consists of neutral two-dimensional layers via hydrogen bonds O-H…O and N-H…O between the molecules, and the layers are connected by weak interactions of the Cu-Cu, Cu-N, π-π and hydrogen bonds to form a three-dimensional network structure.

  19. HYBRID ORBITALS OF CARBON ATOMS IN THE D6hC36 MOLECULE UNDER THE ROTATING ELLIPSOID MODEL

    Institute of Scientific and Technical Information of China (English)

    Tong Guo-ping

    2000-01-01

    The hybrid orbitals of carbon atoms in the D6h C36 molecule arestudied using two rotating ellipsoid models. The model 1 is 1.66R for theshort semi-axis and 2.34R for the long semi-axis, and the model 2 is 1.78R and 2.26R respectively, where R is the C-C bond length. By comparison,we think the model 2 to be more proper in revealing the electronic properties of the D6h C36 molecule. The component of s orbitals in the states hybridized for each of the atoms is much larger than C60, in which the sorbit component is 0.0380 and the porbit is 0.9620. The most component is 0.2098and the least is 0.0482 for model 1; the most is 0.1764 and the least is0.0656 for model 2.

  20. Carbon nanotube quantum dots

    NARCIS (Netherlands)

    Sapmaz, S.

    2006-01-01

    Low temperature electron transport measurements on individual single wall carbon nanotubes are described in this thesis. Carbon nanotubes are small hollow cylinders made entirely out of carbon atoms. At low temperatures (below ~10 K) finite length nanotubes form quantum dots. Because of its small si

  1. Electrical properties and microstructural characterization of Ni/Ta contacts to n-type 6H-SiC

    Science.gov (United States)

    Zhou, Tian-Yu; Liu, Xue-Chao; Huang, Wei; Zhuo, Shi-Yi; Zheng, Yan-Qing; Shi, Er-Wei

    2015-12-01

    A Ni/Ta bilayer is deposited on n-type 6H-SiC and then annealed at different temperatures to form an ohmic contact. The electrical properties are characterized by I-V curve measurement and the specific contact resistance is extracted by the transmission line method. The phase formation and microstructure of the Ni/Ta bilayer are studied after thermal annealing. The crystalline and microstructure properties are analyzed by using glance incident x-ray diffraction (GIXRD), Raman spectroscopy, and transmission electron microscopy. It is found that the transformation from the Schottky to the Ohmic occurs at 1050 °C and the GIXRD results show a distinct phase change from Ta2C to TaC at this temperature. A specific contact resistance of 6.5× 10-5 Ω·cm2 is obtained for sample Ni(80 nm)/Ta(20 nm)/6H-SiC after being annealed at 1050 °C. The formation of the TaC phase is regarded as the main reason for the excellent Ohmic properties of the Ni/Ta contacts to 6H-SiC. Raman and TEM data reveal that the graphite carbon is drastically consumed by the Ta element, which can improve the contact thermal stability. A schematic diagram is proposed to illustrate the microstructural changes of Ni/Ta/6H-SiC when annealed at different temperatures. Project supported by the Innovation Program of the Chinese Academy of Sciences (Grant No. KJCX2-EW-W10), the Shanghai Rising-star Program, China (Grant No. 13QA1403800), the Industry-Academic Joint Technological Innovations Fund Project of Jiangsu Province, China (Grant No. BY2011119), and the National High-tech Research and Development Program of China (Grant Nos. 2013AA031603 and 2014AA032602).

  2. Colloidal Double Quantum Dots.

    Science.gov (United States)

    Teitelboim, Ayelet; Meir, Noga; Kazes, Miri; Oron, Dan

    2016-05-17

    Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole-dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single photon

  3. Ly6h regulates trafficking of alpha7 nicotinic acetylcholine receptors and nicotine-induced potentiation of glutamatergic signaling.

    Science.gov (United States)

    Puddifoot, Clare A; Wu, Meilin; Sung, Rou-Jia; Joiner, William J

    2015-02-25

    α7 nAChRs are expressed widely throughout the brain, where they are important for synaptic signaling, gene transcription, and plastic changes that regulate sensory processing, cognition, and neural responses to chronic nicotine exposure. However, the mechanisms by which α7 nAChRs are regulated are poorly understood. Here we show that trafficking of α7-subunits is controlled by endogenous membrane-associated prototoxins in the Ly6 family. In particular, we find that Ly6h reduces cell-surface expression and calcium signaling by α7 nAChRs. We detect Ly6h in several rat brain regions, including the hippocampus, where we find it is both necessary and sufficient to limit the magnitude of α7-mediated currents. Consistent with such a regulatory function, knockdown of Ly6h in rat hippocampal pyramidal neurons enhances nicotine-induced potentiation of glutamatergic mEPSC amplitude, which is known to be mediated by α7 signaling. Collectively our data suggest a novel cellular role for Ly6 proteins in regulating nAChRs, which may be relevant to plastic changes in the nervous system including rewiring of glutamatergic circuitry during nicotine addiction. PMID:25716842

  4. Explicitly correlated coupled cluster calculations for the benzenium ion (C6H7(+)) and its complexes with Ne and Ar.

    Science.gov (United States)

    Botschwina, Peter; Oswald, Rainer

    2011-11-24

    Explicitly correlated coupled cluster theory at the CCSD(T)-F12x (x = a, b) level (Adler, T. B.; Knizia, G.; Werner, H.-J. J. Chem. Phys. 2007, 127, 221106) has been employed in a study of the benzenium ion (C6H7(+)) and its complexes with a neon or an argon atom. The ground-state rotational constants of C6H7(+) are predicted to be A0 = 5445 MHz, B0 = 5313 MHz, and C0 = 2731 MHz. Anharmonic vibrational wavenumbers of this cation were obtained by combination of harmonic CCSD(T*)-F12a values with anharmonic contributions calculated by double-hybrid density functional theory at the B2PLYP-D level. For the complexes of C6H7(+) with Ne or Ar, the lowest energy minimum is of π-bonded structure. The corresponding dissociation energies D0 are estimated to be 160 and 550 cm(-1), respectively. There is no indication of H-bonds to the aromatic or aliphatic hydrogen atoms. Instead, three nonequivalent local energy minima were found for nuclear configurations where the rare-gas atom lies in the ring-plane and approximatly points to the center of one of the six CC bonds. PMID:21981720

  5. Electron correlations in quantum dots

    CERN Document Server

    Tipton, D L J

    2001-01-01

    Quantum dot structures confine electrons in a small region of space. Some properties of semiconductor quantum dots, such as the discrete energy levels and shell filling effects visible in addition spectra, have analogies to those of atoms and indeed dots are sometimes referred to as 'artificial atoms'. However, atoms and dots show some fundamental differences due to electron correlations. For real atoms, the kinetic energy of electrons dominates over their mutual Coulomb repulsion energy and for this reason the independent electron approximation works well. For quantum dots the confining potential may be shallower than that of real atoms leading to lower electron densities and a dominance of mutual Coulomb repulsion over kinetic energy. In this strongly correlated regime the independent electron picture leads to qualitatively incorrect results. This thesis concentrates on few-electron quantum dots in the strongly correlated regime both for quasi-one-dimensional and two-dimensional dots in a square confining p...

  6. Fuzzy Dot Structure of BG-algebras

    OpenAIRE

    Tapan Senapati; Monoranjan Bhowmik; Madhumangal Pal

    2014-01-01

    In this paper, the notions of fuzzy dot subalgebras is introduced together with fuzzy normal dot subalgebras and fuzzy dot ideals of BG-algebras. The homomorphic image and inverse image are investigated in fuzzy dot subalgebras and fuzzy dot ideals of BG-algebras. Also, the notion of fuzzy relations on the family of fuzzy dot subalgebras and fuzzy dot ideals of BG-algebras are introduced with some related properties.

  7. Council celebrates CERN Control Centre

    CERN Multimedia

    2006-01-01

    With the unveiling of its new sign, the CERN Control Centre was officially inaugurated on Thursday 16 March. To celebrate its startup, CERN Council members visited the sleek centre, a futuristic-looking room filled with a multitude of monitoring screens.

  8. Quantum Dot Sensitized Photoelectrodes

    OpenAIRE

    Thomas Nann; Thomas J. Macdonald

    2011-01-01

    Quantum Dots (QDs) are promising alternatives to organic dyes as sensitisers for photocatalytic electrodes. This review article provides an overview of the current state of the art in this area. More specifically, different types of QDs with a special focus on heavy-metal free QDs and the methods for preparation and adsorption onto metal oxide electrodes (especially titania and zinc oxide) are discussed. Eventually, the key areas of necessary improvements are identified and assessed.

  9. Quantum Dot Sensitized Photoelectrodes

    Directory of Open Access Journals (Sweden)

    Thomas Nann

    2011-11-01

    Full Text Available Quantum Dots (QDs are promising alternatives to organic dyes as sensitisers for photocatalytic electrodes. This review article provides an overview of the current state of the art in this area. More specifically, different types of QDs with a special focus on heavy-metal free QDs and the methods for preparation and adsorption onto metal oxide electrodes (especially titania and zinc oxide are discussed. Eventually, the key areas of necessary improvements are identified and assessed.

  10. Plasmonic fluorescent quantum dots

    OpenAIRE

    Jin, Yongdong; Gao, Xiaohu

    2009-01-01

    Combining multiple discrete components into a single multifunctional nanoparticle could be useful in a variety of applications. Retaining the unique optical and electrical properties of each component after nanoscale integration is, however, a long-standing problem1,2. It is particularly difficult when trying to combine fluorophores such as semiconductor quantum dots with plasmonic materials such as gold, because gold and other metals can quench the fluorescence3,4. So far, the combination of...

  11. Nanocrystal quantum dots

    CERN Document Server

    Klimov, Victor I

    2010-01-01

    ""Soft"" Chemical Synthesis and Manipulation of Semiconductor Nanocrystals, J.A. Hollingsworth and V.I. Klimov Electronic Structure in Semiconductor Nanocrystals: Optical Experiment, D.J. NorrisFine Structure and Polarization Properties of Band-Edge Excitons in Semiconductor Nanocrystals, A.L. EfrosIntraband Spectroscopy and Dynamics of Colloidal Semiconductor Quantum Dots, P. Guyot-Sionnest, M. Shim, and C. WangMultiexciton Phenomena in Semiconductor Nanocrystals, V.I. KlimovOptical Dynamics in Single Semiconductor Quantum Do

  12. Quantum dot nanostructures

    Directory of Open Access Journals (Sweden)

    Mohamed Henini

    2002-06-01

    These sophisticated technologies for the growth of high quality epitaxial layers of compound semiconductor materials on single crystal semiconductor substrates are becoming increasingly important for the development of the semiconductor electronics industry. This article is intended to convey the flavor of the subject by focusing on the technology and applications of self-assembled quantum dots (QDs and to give an introduction to some of the essential characteristics.

  13. Preferential growth of Si films on 6H-SiC(0 0 0 1) C-face

    Energy Technology Data Exchange (ETDEWEB)

    Xie Longfei [Department of Electronic Engineering, Xi' an University of Technology, Xi' an 710048 (China); Chen Zhiming, E-mail: chenzm@xaut.edu.cn [Department of Electronic Engineering, Xi' an University of Technology, Xi' an 710048 (China); Li Lianbi [Department of Electronic Engineering, Xi' an University of Technology, Xi' an 710048 (China); School of Science, Xi' an Polytechnic University, Xi' an 710048 (China); Yang Chen; He Xiaomin; Ye Na [Department of Electronic Engineering, Xi' an University of Technology, Xi' an 710048 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Si films are prepared on SiC C-face by low-pressure chemical vapor deposition. Black-Right-Pointing-Pointer Preferential growth orientation of Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket can be achieved in a temperature range. Black-Right-Pointing-Pointer Si films grown on SiC C-face show a better crystal quality than that of Si-face. Black-Right-Pointing-Pointer Si/SiC structures are analyzed by GULP. Black-Right-Pointing-Pointer Each of Si/SiC C-face interface energy are calculated. - Abstract: Si/SiC heterojunctions are successfully prepared on 6H-SiC(0 0 0 1) C-face by low-pressure chemical vapor deposition. X-ray diffraction and scanning electron microscopy are used to investigate the growth orientation and the surface morphology of the Si films. The results indicate that preferential growth orientation of Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket can be achieved in a temperature range of 825-1000 Degree-Sign C. Within the temperature range, grain size of the Si films becomes larger as temperature increases. Molecular dynamics calculation results indicate that the interface formation energy of the Si(1 1 1)/6H-SiC(0 0 0 1) C-face is smaller than that of Si(1 1 0)/6H-SiC(0 0 0 1) C-face. This is the reason why the Si films prefer to grow on the (1 1 1) crystal plane.

  14. Synthesis, structural characterization, electrical properties and antioxidant activity of [p-(NH3)C6H4NH3]3P6O18·6H2O

    Science.gov (United States)

    Fezai, Ramzi; Mezni, Ali; Kahlaoui, Messaoud; Rzaigui, Mohamed

    2016-09-01

    Single crystals of a novel organic cyclohexaphosphate, [p-(NH3)C6H4NH3]3P6O18.6H2O, have been prepared in aqueous solution. Its crystal structure can be described by a three-dimensional framework where the P6O186- rings are interconnected by hydrogen bonds to form anionic layers between which organic cations are located. Hydrogen bonding network connecting the different components is given. The thermal stability and spectroscopic properties of this material are given too. Its DC and AC electrical conductivities, modulus analysis and dielectric constants have been investigated. The AC conductivity is found to obey the universal power law. The DC electrical conductivity indicates a semiconductor behavior. The kind of the observed conduction is protonic by translocation. X-rays structural and electrical results are correlated. This compound has also been screened for its antioxidant activity, determined in vitro, using 1,1-diphenyl-2-picrylhydrazyl, reducing power, hydroxyl scavenging ability and ferrous ion chelating (FIC) methods and with ascorbic acid as reference.

  15. Ab initial calculations of 6H-SiC(0001) (3×3) surface structural properties%总能计算6H-SiC(0001)(3×3)表面结构特性

    Institute of Scientific and Technical Information of China (English)

    戴宪起; 毕小群

    2003-01-01

    First principle total energy calculations, using the density functional theory (DFT) within the local density approximation (LDA), were performed to investigate the atomic structural properties of (3×3) surfaces of 6H-SiC. The twist model is the energetically favorable one and the rotation of silicon trimer atoms is about 5.4°. Compare to untwist model, a local energetically favorable one that surface atoms are without rotation, the formation energy of twist model is 0.7 eV lower The stable atomic configuration is also given.%本文用第一原理性的密度泛函理论,对6H-SiC(0001)(3×3) 表面再构的原子结构进行了研究.总能计算表明,再构层中的Si原子存在扭转现象,扭转角度为5.4°;无扭转的驰豫模型是一个能量的亚稳结构,它的形成能比扭转模型的高0.7 eV.

  16. The Aube centre; Le Centre de l`Aube

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    This educational booklet is devoted to a general presentation of the Aube radioactive wastes storage centre. After a short presentation of the Andra, the French national agency for the management of radioactive wastes, it gives some general information about radioactive wastes (origin, classification), containers (quality assurance and different types), wastes transportation (planning, safety), and about the Aube centre itself: description, treatment and conditioning of drums (compacting and injection), storage facilities, geological situation of the site, and environmental controls. (J.S.)

  17. Characterization of Cr/6H-SiC(0 0 0 1) nano-contacts by current-sensing AFM

    International Nuclear Information System (INIS)

    The electrical properties and interface chemistry of Cr/6H-SiC(0 0 0 1) contacts have been studied by current-sensing atomic force microscopy (CS-AFM) and X-ray photoelectron spectroscopy (XPS). Cr layers were vapor deposited under ultrahigh vacuum onto both ex situ etched in H2 and in situ Ar+ ion-bombarded samples. The Cr/SiC contacts are electrically non-uniform. Both the measured I-V characteristics and the modeling calculations enabled to estimate changes of the Schottky barrier height caused by Ar+ bombardment. Formation of ohmic nano-contacts on Ar+-bombarded surfaces was observed.

  18. Spin-Spin Relaxation and Karyagin-Gol'danskii Effect in FeCl3·6H2O

    DEFF Research Database (Denmark)

    Thrane, N.; Trumpy, Georg

    1970-01-01

    The Mössbauer spectrum of FeCl3·6 H2O at room temperature is an anomalously asymmetric quadrupole pattern, which is exceptionally sensitive to external magnetic fields. The asymmetry of the spectrum is diminished both when an external magnetic field is applied and when the temperature is decreased....... Qualitatively, the experimental results can be explained by a combination of a temperature-and magnetic-field-dependent spin-spin relaxation and the Karyagin-Gol'danskii effect. This implies that the zero-field splitting is about 20°K between the lowest-lying Kramers doublet, found to be the |±1 / 2...

  19. Theoretical studies of the local structure and electron paramagnetic resonance parameters for tetragonal VO{sup 2+} in C{sub 6}H{sub 7}KO{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ping [Chongqing Jiaotong Univ. (China). School of Science; Li, Ling [Sichuan University of Arts and Science, Dazhou (China). Dept. of Maths and Finance-Economics

    2015-07-01

    The optical spectra, electron paramagnetic resonance parameters (i.e., the spin Hamiltonian parameters, including paramagnetic g factors and the hyperfine structure constants A{sub i}) and the local distortion structure for the tetragonal VO{sup 2+} in C{sub 6}H{sub 7}KO{sub 7} are theoretically studied based on the crystal-field theory and three-order perturbation formulas of a 3d{sup 1} centre in tetragonal site. The magnitude of orbital reduction factor, core polarisation constant κ, and local structure parameters are obtained by fitting the calculated optical spectra and electron paramagnetic resonance parameters to the experimental values. The theoretical results are in reasonable agreement with the experimental values.

  20. Contemporary design for 'landmark' centre.

    Science.gov (United States)

    2009-08-01

    As one of the UK's largest builders of healthcare facilities, construction company Morgan Ashurst is accustomed to delivering complex, challenging hospital projects. The construction of a new oncology centre at Musgrove Park Hospital, Taunton for Taunton and Somerset NHS Foundation Trust-- said to be the first new stand-alone radiotherapy centre to be built in the UK for almost 20 years--was no exception. Health Estate Journal reports. PMID:19711668

  1. The centre of the action

    CERN Document Server

    2008-01-01

    The CERN Control Centre (CCC) has all the ingredients of an action movie control room: hundreds of screens, technicians buzzing in and out, huge floor-to-ceiling windows revealing the looming vista of a mountain range, flashing lights, microphones… This is the place where not just the LHC, but the whole of CERN’s accelerator complex and technical support is based - truly the centre of the action at CERN.

  2. Destabilization of the 6H-SrIrO3 polymorph through partial substitution of zinc and lithium

    DEFF Research Database (Denmark)

    Bremholm, Martin; K. Kim, Cindi; Hirai, Daigo;

    2012-01-01

    We report on the destabilization of the 6H-SrIrO3 polymorph through partial substitutions of zinc and lithium for iridium to form perovskites. The perovskites crystallize in the orthorhombic space group Pbnm: SrIr1−xZnxO3 is found for 0.25 ≤ x ≤ 0.33, while SrIr1−xLixO3 is found only for x = 0.......25. The Zn and Li ions are randomly distributed in the B-site lattice. Analysis shows that the perovskite stabilization is not driven by changes in average ionic size but rather is due to destabilization of the face-sharing octahedra that are present in 6H-type SrIrO3. Magnetic susceptibility measurements...... show Curie–Weiss behavior, with relatively large temperature independent contributions, and that the iridium atoms have low effective moments, 0.52 to 1.08 μB per Ir. The resistivity of SrIr0.67Zn0.33O3, characterized by Mott variable range hopping type semiconducting behavior, indicates...

  3. Stretched chemical bonds in Si6H6: a transition from ring currents to localized π-electrons?

    International Nuclear Information System (INIS)

    Motivated by solid-state studies on the cleavage force in Si, and the consequent stretching of chemical bonds, we here study bond stretching in the, as yet unsynthesized, free space molecule Si6H6. We address the question as to whether substantial bond stretching (but constrained to uniform scaling on all bonds) can result in a transition from ring current behaviour, characteristic say of benzene at its equilibrium geometry, to localized π-electrons on Si atoms. Some calculations are also recorded on dissociation into 6 SiH radicals. While the main studies have been carried out by unrestricted Hartree-Fock (HF) theory, the influence of electron correlation has been examined using two forms of density functional theory. Planar Si6H6 treated by HF is bound to be unstable, not all vibrational frequencies being real. Some buckling is then allowed, which results in real frequencies and stability. Evidence is then provided that the non-planar structure, as the Si-Si distance is increased, exhibits π-electron localization in the range 1.2-1.5 times the equilibrium distance

  4. Material removal mechanism of 6H-SiC studied by nano-scratching with Berkovich indenter

    Science.gov (United States)

    Meng, Binbin; Zhang, Yong; Zhang, Feihu

    2016-03-01

    The aim of this paper was to analyze the deformation characteristics and material removal mechanism of mono-crystal silicon carbide. The nano-scratching tests were conducted on the surface of 6H-SiC (0001) by using Berkovich nano-indenter. In the presence of various characterization techniques, a variety of new achievements have been reached. Phase transformation behavior in the nano-scratching process of mono-crystal silicon carbide (6H-SiC) is revealed by using the transmission electron microscope in this work. Amorphous phase and dislocation activities are found near the surface area under the bottom of the scratch which stands as the major cause triggering the plastic removal of this material, with no other forms of crystalline structure found, by which the plastic removal mechanism of mono-crystal silicon carbide was well identified. With a crack-free surface that had been processed, the chip broke away from the bulk in the form of plastic mode, but the subsurface was covered by cracks with their lengths many times longer than the machined depth. The results of laser Raman indicated that residual amorphous phase exits in the chips under the condition of the plastic removal of this material.

  5. Molecular dynamics study of temperature-dependent ripples in monolayer and bilayer graphene on 6H-SiC surfaces

    Institute of Scientific and Technical Information of China (English)

    Tang Chao; Wei Xiao-Lin; Tan Xin; Peng Xiang-Yang; Sun Li-Zhong; Zhong Jian-Xin

    2012-01-01

    Using classical molecular dynamics and a simulated annealing technique,we show that microscopic corrugations occur in monolayer and bilayer graphene on 6H-SiC substrates.From an analysis of the atomic configurations,two types of microscopic corrugations are identified,namely periodic ripples at room temperature and random ripples at high temperature.Two different kinds of ripple morphologies,each with a periodic structure,occur in the monolayer graphene due to the existence of a coincidence lattice between graphene and the SiC terminated surface (Si- or C-terminated surface).The effect of temperature on microscopic ripple morphology is shown through analysing the roughness of the graphene.A temperature-dependent multiple bonding conjugation is also shown by the broad distribution of the carbon-carbon bond length and the bond angle in the rippled graphene on the SiC surface.These results provide atomic-level information about the rippled graphene layers on the two polar faces of the 6H-SiC substrate,which is useful not only for a better understanding of the stability and structural properties of graphene,but also for the study of the electronic properties of graphene-based devices.

  6. Stretched chemical bonds in Si6H6: A transition from ring currents to localized pi-electrons?

    CERN Document Server

    Grassi, A; Pucci, R; Angilella, G G N; Bartha, F; March, N H

    2004-01-01

    Motivated by solid-state studies on the cleavage force in Si, and the consequent stretching of chemical bonds, we here study bond stretching in the, as yet unsynthesized, free space molecule Si6H6. We address the question as to whether substantial bond stretching (but constrained to uniform scaling on all bonds) can result in a transition from ring current behaviour, characteristic say of benzene at its equilibrium geometry, to localized pi-electrons on Si atoms. Some calculations are also recorded on dissociation into 6 SiH radicals. While the main studies have been carried out by unrestricted Hartree-Fock (HF) theory, the influence of electron correlation has been examined using two forms of density functional theory. Planar Si6H6 treated by HF is bound to be unstable, not all vibrational frequencies being real. Some buckling is then allowed, which results in real frequencies and stability. Evidence is then provided that the non-planar structure, as the Si-Si distance is increased, exhibits pi-electron loca...

  7. Inter-dot coupling effects on transport through correlated parallel coupled quantum dots

    Indian Academy of Sciences (India)

    Shyam Chand; G Rajput; K C Sharma; P K Ahluwalia

    2009-05-01

    Transport through symmetric parallel coupled quantum dot system has been studied, using non-equilibrium Green function formalism. The inter-dot tunnelling with on-dot and inter-dot Coulomb repulsion is included. The transmission coefficient and Landaur–Buttiker like current formula are shown in terms of internal states of quantum dots. The effect of inter-dot tunnelling on transport properties has been explored. Results, in intermediate inter-dot coupling regime show signatures of merger of two dots to form a single composite dot and in strong coupling regime the behaviour of the system resembles the two decoupled dots.

  8. Vibrational spectra and dispersion analysis of K2Ni(SeO4)2·6H2O Tutton salt single crystal doped with K2Ni(SO4)2·6H2O.

    Science.gov (United States)

    Ivanovski, Vladimir; Mayerhöfer, Thomas G

    2013-10-01

    Dispersion analysis of the polarized IR reflectance spectra of K2Ni(SeO4)2·6H2O doped with K2Ni(SO4)2·6H2O has been performed. Vibrational parameters like oscillator strength, attenuation constant and frequency of the transversal phonons for the modes of Au symmetry type plus the orientation of the transition dipole moments for the modes of Bu symmetry type in the ac crystal plane have been obtained. The spectra-structure correlation of the H2O stretching vibrations show that bands appearing in the spectra for polarization of the external radiation oriented along the b axis are mainly due to the H2O stretching vibrations of one of the three crystallographically distinct sets of water molecules. The orientation of the transition dipoles of stretching vibrations of the selenate ion differ from the characteristic spectra of the sulfate analog in that no mutually perpendicular transition dipoles are found in the ac crystal plane. Water librational bands masked with the bands of the ν4(SO4(2-)) mode in the sulfate analog have now been unveiled and assigned. The ratio between the oscillator strength and the attenuation constant appears to be a helpful tool in the assignment of the sulfate stretching vibrations and water librations. The vibrational and orientational characteristics of the ν4(SeO4(2-)) modes were obtained. Тhe ν3(SO4(2-)) frequency region of the isomorphously isolated SO4(2-) ion in the K2Ni(SeO4)2·6H2O matrix was investigated in some detail. Contrary to the expected three, four bands can be identified. Three of them were assigned to ν3(SO4(2-)) based on the orientation of the transition dipole moments. On the basis of the IR, but also Raman spectra of the pure and mixed crystals, a discussion of the influence of the potential field and the hydrogen bonds with the change in the volume of the unit cell is given. PMID:23796943

  9. Training centres - organization and management

    International Nuclear Information System (INIS)

    In the lecture 'Training centres - organization and management' some principles and requirements which influence the organization, management and activity pattern of nuclear training centres, are briefly introduced. It is demonstrated, step by step, how these general principles are implemented in the development of the Czechoslovak nuclear power programme, it means, how the training of the NPP personnel proceeds in Czechoslovak nuclear training centres. General principles which are selected: a connection between the capacity of the training centre and the scope and needs of the nuclear power programme, a position of the training center within the institutional set-up, a structure and organization of the training system which complies with the system of NPP construction, reflect the pattern and the activity of the nuclear training centre and nuclear power technical level, a research group of workers in the nuclear training centre, main tasks and technical facilities, management of the training process and a transfer of knowledge and research results into the training process. The lecture is supplemented by pictures and slides. (orig.)

  10. Fabrication of 3-inch HPSI 6H-SiC Crystal%3英寸高纯半绝缘6H-SiC单晶的研制

    Institute of Scientific and Technical Information of China (English)

    王利杰; 洪颖; 齐海涛; 冯玢; 王香泉; 郝建民; 严如岳

    2011-01-01

    采用物理气相传输(PVT)工艺,成功制备出3英寸高纯半绝缘(HPSI)6H-SiC单晶。依据氮在碳化硅晶格中占碳位的规律,通过生长过程温度和压力等工艺参数的优化,减少生长前沿碳空位的数量,实现了在较高碳硅比气氛下低氮含量碳化硅单晶生长的目标。二次离子质谱(SIMS)测试给出了晶体中氮及其他杂质的控制水平,证明单晶的高纯属性;非接触电阻率Mapping(CORE-MA)和电子顺磁共振(EPR)测试进一步证实其高纯半绝缘特性。%3-inch high purity semi-insulating(HPSI)6H-SiC single crystal is prepared successfully by physical vapor transport(PVT)method.It is known that nitrogen occupys carbon site in semi-insulating SiC and is a unintended dopant which must be removed.To decrease the concentration of nitrogen impurity in the SiC crystal,the high C/Si ratio vapor composition on the growing surface is designed by controlling the growth temperature and pressure effectively,which creats low percentage of carbon vacancy in the growth surface.After growth,COREMA(Contactless Resistivity Mapping),SIMS(Secondary Ion Mass Spectroscopy)and EPR(Electron Paramagnetic Resonance)tests are carried out,and the semi-insulating,high purity and intrinsic defect compensation properties are proved.

  11. Near-surface recrystallization of the amorphous implanted layer of ion implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Kuhudzai, R.J., E-mail: joeykuhu@yahoo.com [Physics Department, University of Pretoria, Pretoria (South Africa); Berg, N.G. van der; Malherbe, J.B.; Hlatshwayo, T.T.; Theron, C.C. [Physics Department, University of Pretoria, Pretoria (South Africa); Buys, A.V.; Botha, A.J. [Laboratory for Microscopy and Microanalysis, University of Pretoria (South Africa); Wendler, E.; Wesch, W. [Institut Für Festköperphysik, Friedrich-Schiller-Universität Jena, Jena (Germany)

    2014-08-01

    The recrystallization and subsequent crystal growth during annealing of amorphous surface layers on 6H-SiC produced by ion implantation is investigated. Amorphous surface layers were produced by ion implantation of 360 keV ions of iodine, silver, xenon, cesium and strontium into single crystalline 6H-silicon carbide samples. The ion fluence for all the implantations were in the order of 10{sup 16} cm{sup −2}. Vacuum annealing of the damaged silicon carbide samples was then performed. The microstructure of SiC surfaces before and after annealing was investigated using a high resolution field emission scanning electron microscope (SEM). SEM analysis was complimented by Atomic Force Microscopy (AFM). SEM images acquired by an in-lens detector using an accelerating voltage of 2 kV show nano-crystallites developed for all implanted samples after annealing. Larger and more faceted crystallites along with elongated thin crystallites were observed for iodine and xenon implanted 6H-SiC. Crystallites formed on surfaces implanted with strontium and cesium were smaller and less faceted. Strontium, silver and cesium implanted samples also exhibited more cavities on the surface. AFM was used to evaluate the effect of annealing on the surface roughness. For all the amorphous surfaces which were essentially featureless, the root mean square (rms) roughness was approximately 1 nm. The roughness increased to approximately 17 nm for the iodine implanted sample after annealing with the surface roughness below this value for all the other samples. AFM also showed that the largest crystals grew to heights of about 17, 20, 45, 50 and 65 nm for Sr, Cs, Ag, Xe and I implanted samples after annealing at 1200 °C for 5 h respectively. SEM images and AFM analysis suggest that iodine is more effective in promoting crystal growth during the annealing of bombardment-induced amorphous SiC layers than the rest of the ions we implanted. In samples of silicon carbide co-implanted with iodine and

  12. Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

    Science.gov (United States)

    Alert, Bianca; Michalik, Andreas; Helduser, Sascha; Mouritsen, Henrik; Güntürkün, Onur

    2015-01-01

    Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

  13. Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

    Directory of Open Access Journals (Sweden)

    Bianca Alert

    Full Text Available Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

  14. The ideal Atomic Centre; Le Centre Atomique ideal

    Energy Technology Data Exchange (ETDEWEB)

    Mas, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents considerations which should prove to be of interest to all those who have to design, to construct and to operate a nuclear research centre. A large number of the ideas presented can also be applied to non-nuclear scientific research centres. In his report the author reviews: various problems with which the constructor is faced: ground-plan, infrastructure, buildings and the large units of scientific equipment in the centre, and those problems facing the director: maintenance, production, supplies, security. The author stresses the relationship which ought to exist between the research workers and the management. With this aim in view he proposes the creation of National School for Administration in Research which would train administrative executives for public or private organisations; they would be specialised in the fields of fundamental or applied research. (author) [French] L'auteur propose une base de reflexions a tous ceux qui doivent concevoir, realiser et faire vivre un Centre d'Etudes Nucleaires. Un grand nombre des idees exprimees peut d'ailleurs s'appliquer a un Centre d'Etudes Scientifiques non nucleaires. Dans son ouvrage, l'auteur passe en revue les differents problemes qui se posent au constructeur: plan, masse, infrastructure, batiments et grands appareils du Centre, et ceux qu'a a resoudre le directeur: entretien, fabrication, approvisionnements, securite. L'auteur insiste sur l'aspect des rapports qui doivent exister entre les chercheurs et ceux qui les administrent. Il propose a cette fin la creation d'une Ecole Nationale d'Administration de la Recherche qui formerait des cadres administratifs pour les organismes publics ou prives, specialises dans la Recherche fondamentale ou appliquee. (auteur)

  15. The simulation of temperature dependence of responsivity and response time for 6H-SiC UV photodetector

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi-Men; Zhou Yong-Hua; Zhang Yu-Ming

    2007-01-01

    In this paper the temperature dependence of responsivity and response time for 6H-SiC ultraviolet (UV) photodetector is simulated based on numerical model in the range from 300 K to 900 K. The simulation results show that the responsivity and the response time of device are less sensitive to temperature and this kind of UV photodetector has excellent temperature stability. Also the effects of device structure and bias voltage on the responsivity and the response time are presented. The thicker the drift region is, the higher the responsivity and the longer the response time are. So the thickness of drift region has to be carefully designed to make trade-off between responsivity and response time.

  16. Disodium hydrogen citrate sesquihydrate, Na2HC6H5O7(H2O)1.5.

    Science.gov (United States)

    Rammohan, Alagappa; Sarjeant, Amy A; Kaduk, James A

    2016-07-01

    The crystal structure of disodium hydrogen citrate sesquihydrate, 2Na2 (+)·C6H6O7 (2-)·1.5H2O, has been solved and refined using laboratory X-ray single-crystal diffraction data, and optimized using density functional techniques. The asymmetric unit contains two independent hydrogen citrate anions, four sodium cations and three water molecules. The coordination polyhedra of the cations (three with a coordination number of six, one with seven) share edges to form isolated 8-rings. The un-ionized terminal carb-oxy-lic acid groups form very strong hydrogen bonds to non-coordinating O atoms, with O⋯O distances of 2.46 Å. PMID:27555936

  17. Disodium hydrogen citrate sesquihydrate, Na2HC6H5O7(H2O)1.5

    Science.gov (United States)

    Rammohan, Alagappa; Sarjeant, Amy A.; Kaduk, James A.

    2016-01-01

    The crystal structure of disodium hydrogen citrate sesquihydrate, 2Na2 +·C6H6O7 2−·1.5H2O, has been solved and refined using laboratory X-ray single-crystal diffraction data, and optimized using density functional techniques. The asymmetric unit contains two independent hydrogen citrate anions, four sodium cations and three water molecules. The coordination polyhedra of the cations (three with a coordination number of six, one with seven) share edges to form isolated 8-rings. The un-ionized terminal carb­oxy­lic acid groups form very strong hydrogen bonds to non-coordinating O atoms, with O⋯O distances of 2.46 Å.

  18. Electrical properties of high-dose nitrogen-implanted and rapid thermal annealed 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Abe, K. E-mail: abe@elcom.nitech.ac.jp; Eryu, O.; Kogi, O.; Nakashima, K

    2003-05-01

    The annealing time dependence of surface morphologies, crystallinity, and electrical characteristics for the high-dose nitrogen-implanted 6H-SiC has been investigated. Rapid thermal annealing (RTA) was performed at the temperature ranging from 1600 to 1850 deg. C for 20 s. In comparison with conventional furnace annealed (FA) samples (1550-1650 deg. C, 180 s in argon), the RTA samples had smoother surfaces and better crystallinity. While no reduction in the thickness of the implanted layer and no redistribution of implanted nitrogen atoms were observed in the RTA samples, the thickness of the implanted layer was reduced by FA. The sheet resistance and electron concentration of the RTA sample at 1750 deg. C were comparable to those of the FA sample at 1550 deg. C. We will discuss the difference between the RTA and the FA samples.

  19. Raman analysis of epitaxial graphene on 6H-SiC (000(1)) substrates under low pressure environment

    Institute of Scientific and Technical Information of China (English)

    Wang Dangchao; Zhang Yuming; Zhang Yimen; Lei Tianmin; Guo Hui; Wang Yuehu; Tang Xiaoyan; Wang Hang

    2011-01-01

    This article investigates the formation mechanism of epitaxial graphene on 6H-SiC (000(1)) substrates under low pressure of 2 mbar environment.It is shown that the growth temperature dramatically affects the formation and quality of epitaxial graphene.The higher growing temperature is of great benefit to the quality of epitaxial graphene and also can reduce the impact of the substrate for graphene.By analyzing Raman data,we conclude that epitaxial graphene grown at 1600 ℃ has a turbostratic graphite structure.The test from scanning electron microscopy (SEM) indicates that the epitaxial graphene has a size of 10μm.This research will provide a feasible route for fabricating larger size ofepitaxial graphene on SiC substrate.

  20. Disodium hydrogen citrate sesquihydrate, Na2HC6H5O7(H2O1.5

    Directory of Open Access Journals (Sweden)

    Alagappa Rammohan

    2016-07-01

    Full Text Available The crystal structure of disodium hydrogen citrate sesquihydrate, 2Na2+·C6H6O72−·1.5H2O, has been solved and refined using laboratory X-ray single-crystal diffraction data, and optimized using density functional techniques. The asymmetric unit contains two independent hydrogen citrate anions, four sodium cations and three water molecules. The coordination polyhedra of the cations (three with a coordination number of six, one with seven share edges to form isolated 8-rings. The un-ionized terminal carboxylic acid groups form very strong hydrogen bonds to non-coordinating O atoms, with O...O distances of 2.46 Å.

  1. Effects of Buffer Layer on Hetero-Epi-Growth of SiCGe on 6H-SiC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Growth of SiCGe ternary alloy on 6H-SiC in a conventional hot-wall CVD system was initially studied. SiH4, GeH4 and C3H8 were employed as silicon, germanium and carbon source, respectively, while H2 was employed as the carrier gas. To reduce the heavy lattice mismatch between the film and the substrate, a 3C-SiC buffer layer was inserted between them in a CVD process. Optimizing the growth conditions was discussed. The samples were measured by means of SEM, SAXRD (Small Angle X-Ray Diffraction). It is shown that use of the 3C-SiC buffer layer is an effective way to improve the quality of the ternary alloy.

  2. Stable Electrical Operation of 6H-SiC JFETs and ICs for Thousands of Hours at 500 C

    Science.gov (United States)

    Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Beheim, Glenn M.; Okojie, Robert S.; Chang, Carl W.; Meredith, Roger D.; Ferrier, Terry L.; Evans, Laura J.; Krasowski, Michael J.; Prokop, Norman F.

    2008-01-01

    The fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500 C in air ambient is reported. These devices are based on an epitaxial 6H-SiC junction field-effect transistor process that successfully integrated high temperature ohmic contacts, dielectric passivation, and ceramic packaging. Important device and circuit parameters exhibited less than 10% of change over the course of the 500 C operational testing. These results establish a new technology foundation for realizing durable 500 C ICs for combustion-engine sensing and control, deep-well drilling, and other harsh-environment applications.

  3. Activation and control of visible single defects in 4H-, 6H-, and 3C-SiC by oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lohrmann, A.; Klein, J. R.; Prawer, S.; McCallum, J. C. [School of Physics, The University of Melbourne, Victoria 3010 (Australia); Castelletto, S. [School of Engineering, RMIT University, Melbourne, Victoria 3001 (Australia); Ohshima, T. [SemiConductor Analysis and Radiation Effects Group, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Bosi, M.; Negri, M. [IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma (Italy); Lau, D. W. M.; Gibson, B. C. [ARC Centre of Excellence for Nanoscale BioPhotonics, School of Science, RMIT University, Melbourne, Victoria 3001 (Australia); Johnson, B. C. [ARC Centre of Excellence for Quantum Computing and Communication Technology, School of Physics, University of Melbourne, Victoria 3010 (Australia)

    2016-01-11

    In this work, we present the creation and characterisation of single photon emitters at the surface of 4H- and 6H-SiC, and of 3C-SiC epitaxially grown on silicon. These emitters can be created by annealing in an oxygen atmosphere at temperatures above 550 °C. By using standard confocal microscopy techniques, we find characteristic spectral signatures in the visible region. The excited state lifetimes are found to be in the nanosecond regime in all three polytypes, and the emission dipoles are aligned with the lattice. HF-etching is shown to effectively annihilate the defects and to restore an optically clean surface. The defects described in this work have ideal characteristics for broadband single photon generation in the visible spectral region at room temperature and for integration into nanophotonic devices.

  4. Growth of fcc(111) Dy multi-height islands on 6H-SiC(0001) graphene.

    Science.gov (United States)

    Hershberger, M T; Hupalo, M; Thiel, P A; Tringides, M C

    2013-06-01

    Graphene based spintronic devices require an understanding of the growth of magnetic metals. Rare earth metals have large bulk magnetic moments so they are good candidates for such applications, and it is important to identify their growth mode. Dysprosium was deposited on epitaxial graphene, prepared by thermally annealing 6H-SiC(0001). The majority of the grown islands have triangular instead of hexagonal shapes. This is observed both for single layer islands nucleating at the top of incomplete islands and for fully completed multi-height islands. We analyze the island shape distribution and stacking sequence of successively grown islands to deduce that the Dy islands have fcc(111) structure, and that the triangular shapes result from asymmetric barriers to corner crossing.

  5. Study on Λ6H hypernucleus by the (π−, K+ reaction at J-PARC

    Directory of Open Access Journals (Sweden)

    Sugimura H.

    2014-03-01

    Full Text Available We carried out an experiment to produce the neutron-rich hypernucleus Λ6H via the (π−, K+ reaction on 6Li target at the pion beam momentum of 1.2 GeV/c (J-PARC E10. In order to calibrate the scale of the missing-mass or of the Λ binding energy of the hypernucleus, we also measured the 12C(π+, K+ Λ12C, p(π−, K+Σ− and p(π+, K+Σ+reactions. The experiment was performed at the J-PARC Hadron Hall K1.8 beam line in December 2012 and January 2013. The overall collected data sample corresponds to an integrated beam intensity of 1.65 × 1012 pions.

  6. The Galactic centre pulsar population

    CERN Document Server

    Chennamangalam, Jayanth

    2013-01-01

    The recent discovery of a magnetar in the Galactic centre region has allowed Spitler et al. to characterize the interstellar scattering in that direction. They find that the temporal broadening of the pulse profile of the magnetar is substantially less than that predicted by models of the electron density of that region. This raises the question of what the plausible limits for the number of potentially observable pulsars - i.e., the number of pulsars beaming towards the Earth - in the Galactic centre region are. In this paper, using realistic assumptions, we show that the potentially observable population of pulsars in the inner parsec has a conservative upper limit of $\\sim$950, and that it is premature to conclude that the number of pulsars in this region is small. We also show that the observational results so far are consistent with this number and make predictions for future radio pulsar surveys of the Galactic centre.

  7. Construction of the Wigner Data Centre

    CERN Multimedia

    2013-01-01

    A remote extension of the CERN data centre has recently been inaugurated. Hosted at the Wigner Research Centre for Physics in Hungary, it provides extra computing power required to cover CERN’s needs. This video presents the construction of the Wigner Data Centre from initial demolishing work through to its completion and details the major technical characteristics of the Data Centre.

  8. Et2NH2C6H3(CO23SnBr2.4H2O: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    DAOUDA NDOYE

    2014-01-01

    Full Text Available The title compound has been obtained on allowing [C6H3(CO23(Et2NH23] to react with SnBr4. The molecular structure of Et2NH2C6H3(CO23SnBr2.4H2O has been determined on the basis of the infrared data. The suggested structure is a dimer in which each tin atom is hexacoordinated by two chelating C6H3(CO233- anions and two Br atoms. Cy2NH2+cations are involved through hydrogen bonds with non-coordinating CO2 groups. The suggested structure is a cage.

  9. Mass analyzed threshold ionization of hydrogen bonded clusters of biological molecules: the 3-methylindole·C6H6 complex

    International Nuclear Information System (INIS)

    The mass analyzed threshold ionization (MATI) technique has been used for measuring the adiabatic ionization energy of the 3-methylindole·C6H6 cluster (58 018 cm-1) and the binding energies in its ground ionic (4448 cm-1) and ground neutral state (1775 cm-1). We compare our results with those recently obtained for the 3-methylindole·H2O and the indole·C6H6 cluster. The small influence of methylation on the binding energies confirms the π-hydrogen bonding character in the 3-methylindole·C6H6 complex

  10. Complex dynamics in planar two-electron quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Schroeter, Sebastian Josef Arthur

    2013-06-25

    Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two

  11. Complex dynamics in planar two-electron quantum dots

    International Nuclear Information System (INIS)

    Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two-electron quantum dots an

  12. Aspects of transmetallation reactions of 2-Me2NCH2C6H4- and 2,6-(Me2NCH2)-C6H3-metal (Pd,Pt,Hg,Tl) complexes with metal carboxylates and low-valent metal (Pd,Pt) complexes

    NARCIS (Netherlands)

    Koten, G. van; Ploeg, A.F.M.J. van der; Vrieze, K.

    1981-01-01

    A study has been made of reactions involving organometallic compounds containing ortho-Me{2}NCH{2} substituted aryl ligands. The single step syntheses of the new compounds [(2-Me{2}NCH{2}C{6}H{4}){2}TlCl], [ [{(S)-2-Me{2}NCH(Me)C{6}H{4}}{2}TlCl], [{(S)-2-Me{2}NCH(Me)C{6}H{4}}TlCl{2}], [{2, 6-(Me{2}N

  13. Expression of the Ly-6 family proteins Lynx1 and Ly6H in the rat brain is compartmentalized, cell-type specific, and developmentally regulated

    DEFF Research Database (Denmark)

    Thomsen, Morten Skøtt; Cinar, Betül; Jensen, Majbrit Myrup;

    2014-01-01

    The Ly-6 superfamily of proteins, which affects diverse processes in the immune system, has attracted renewed attention due to the ability of some Ly-6 proteins to bind to and modulate the function of neuronal nicotinic acetylcholine receptors (nAChRs). However, there is a scarcity of knowledge...... regarding the distribution and developmental regulation of these proteins in the brain. We use protein cross-linking and synaptosomal fractions to demonstrate that the Ly-6 proteins Lynx1 and Ly6H are membrane-bound proteins in the brain, which are present on the cell surface and localize to synaptic...... demonstrate that Lynx1 and Ly6H are expressed in cultured neurons, but not cultured micro- or astroglial cultures. In addition, Lynx1, but not Ly6H was detected in the CSF. Finally, we show that the Ly-6 proteins Lynx1, Lynx2, Ly6H, and PSCA, display distinct expression patterns during postnatal development...

  14. LDE centres: sprint or marathon?

    NARCIS (Netherlands)

    Bonger, S.; Van Rein, E.

    2015-01-01

    The aim of the Strategic Leiden-Delft-Erasmus Alliance, established by the three universities in 2012, was to improve research and education and competitiveness. Projects are intended to develop from the ground up, which led to the establishment of eight joint centres in 2013. A quick look around re

  15. Dimetallaborane analogues of the octaboranes of the type Cp2M2B6H10: structural variations with changes in the skeletal electron count.

    Science.gov (United States)

    Brânzanic, Adrian M V; Lupan, Alexandru; King, R Bruce

    2016-05-31

    The structures and energetics of the complete series of hydrogen-rich dimetallaboranes Cp2M2B6H10 and Cp*2M2B6H10 (Cp = η(5)-C5H5; Cp* = η(5)-Me5C5; M = Pd, Pt; Rh, Ir; Ru, Os; Re; Mo, W; Ta), including the experimentally known Cp*2Rh2B6H10 and Cp*2W2B6H10 (Cp* = η(5)-Me5C5), have been investigated by density functional theory. The lowest energy structures of the hyperelectronic Cp2M2B6H10 (M = Pd, Pt; Rh, Ir) systems have central M2B6 frameworks with a hexagonal open face similar to the B8 networks in arachno-B8H14 and nido-B8H12. The two lowest energy structures for Cp2Rh2B6H10 and Cp*2Rh2B6H10, lying within 1 kcal mol(-1) of energy, differ only in the locations of the bridging hydrogen atoms around the hexagonal hole consistent with the experimentally observed fluxionality of the hydrogen atoms in Cp*2Rh2B6H10. Most of the lowest energy Cp2M2B6H10 (M = Ru, Os) structures also have a central M2B6 framework similar to B8H12, typically with such additional features as an additional metal-metal bond or a formal metal-metal double bond. A common motif for the low-energy structures of the hypoelectronic Cp2M2B6H10 (M = Re; Mo, W; Ta) systems, including the experimentally known Cp*2W2B6H10, is a central M2B4 octahedron with its two M2B faces capped by the remaining boron atoms and with four M-B edges bridged by hydrogen atoms. Such structures can also be considered as oblatonido structures derived from the experimentally known 9-vertex oblatocloso Cp*2Re2B7H7 structure by removal of the unique degree 4 vertex atom. PMID:27186632

  16. Mn fraction substitutional site and defects induced magnetism in Mn-implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, K., E-mail: Khalid.bouziane@uir.ac.ma [Pôle Energies Renouvelables et Etudes Pétrolières, Université Internationale de Rabat, 11000 – Salé el Jadida, Technopolis (Morocco); Al Azri, M.; Elzain, M. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123 (Oman); Chérif, S.M. [LSPM (CNRS-UPR 3407), Université Paris, 13-Nord, 99, Avenue Jean Baptiste Clément, 93430 Villetaneuse (France); Mamor, M. [Equipe MSISM, Faculté Poly-Disciplinaire, B.P. 4162 Safi, Université Cadi Ayyad, Marrakech (Morocco); Declémy, A. [Institut P’, CNRS – Université de Poitiers – ENSMA, UPR 3346, SP2MI – Téléport 2, 11 boulevard Marie et Pierre Curie, BP 30179, F-86962 Futuroscope Chasseneuil Cedex (France); Thomé, L. [CSNSM-Orsay, Bât. 108, Université d’Orsay, F-91405 Orsay (France)

    2015-05-25

    Highlights: • Shallow Mn-implanted 6H-SiC crystal. • Correlation between Mn-substitutional site concentration and magnetism. • Correlation between defects nature surrounding Mn site and magnetism. • Correlation of magnetism in Mn-doped SiC to Mn at Si sites and vacancy-related defect. - Abstract: n-type 6H-SiC (0 0 0 1) single crystal substrates were implanted with three fluences of manganese (Mn{sup +}) ions: 5 × 10{sup 15}, 1 × 10{sup 16} and 5 × 10{sup 16} cm{sup −2} with implantation energy of 80 keV at 365 °C to stimulate dynamic annealing. The samples were characterized using Rutherford backscattering channeling spectroscopy (RBS/C), high-resolution X-ray diffraction technique (HRXRD), and Superconducting Quantum Interference Device (SQUID) techniques. Two main defect regions have been identified using RBS/C spectra fitted with the McChasy code combined to SRIM simulations. Intermediate defects depth region is associated with vacancies (D{sub V}) and deeper defect (D{sub N}) essentially related to the Si and C interstitial defects. The defect concentration and the maximum perpendicular strain exhibit similar increasing trend with the Mn{sup +} fluence. Furthermore, the amount of Mn atoms at Si substitutional sites and the corresponding magnetic moment per Mn atom were found to increase with increasing Mn fluence from 0.7 μ{sub B} to 1.7 μ{sub B} and then collapsing to 0.2 μ{sub B}. Moreover, a strong correlation has been found between the magnetic moment and the combination of both large D{sub V}/D{sub N} ratio and high Mn at Si sites. These results are corroborated by our ab initio calculations considering the most stable configurations showing that besides the amount of Mn substituting Si sites, local vacancy-rich environment is playing a crucial role in enhancing the magnetism.

  17. Features of the seasonal variation of the semidiurnal, terdiurnal and 6-h components of ozone heating evaluated from Aura/MLS observations

    OpenAIRE

    Xu, J.; Smith, A K; Jiang, G.; Yuan, W.; Gao, H.

    2012-01-01

    This paper presents the thermal forcing of the semidiurnal, terdiurnal, and 6-h components of the migrating tide induced by ozone heating in stratosphere and lower mesosphere. The heating as a function of local time is determined from the global ozone observed by the Microwave Limb Sounder on the Aura satellite. The harmonic components of the heating rates of the semidiurnal, terdiurnal and the 6-h periodicities are calculated using the Strobel/Zhu parameterized model and then decomposed into...

  18. Growth and structure of K2NixCo(1–x)(SO4)2 · 6H2O single crystals

    International Nuclear Information System (INIS)

    Single crystals of the K2NixCo(1–x)(SO4)2 · 6H2O composition are grown by spontaneous flux crystallization. More exact chemical formulas of the single crystals are determined based on the diffraction data as K2Co(SO4)2 · 6H2O (I), K2(Co0.657Ni0.343)(SO4)2 · 6H2O (II), K2(Co0.226Ni0.774)(SO4)2 · 6H2O (III), K2(Co0.216Ni0.784)(SO4)2 · 6H2O (IV), and K2Ni(SO4)2 · 6H2O (V). The substitution of nickel atoms for cobalt atoms in structure I results in a shortening of all (Co,Ni)–O interatomic distances. With increasing Ni concentration, the (Co,Ni)–O2 distance shortens to a lesser degree than the (Co,Ni)–O1 and (Co,Ni)–O3 distances and, as a consequence, the distortion of (Co,Ni)O6 octahedra decreases. NiO6 polyhedra are less distorted than CoO6 octahedra. The analysis of difference syntheses of electron density shows that the number of uninterpretable peaks on the maps of mixed crystals II, III, and IV, as well as on the map of K2Co(SO4)2 · 6H2O, is larger with respect to those of structure K2Ni(SO4)2 · 6H2O

  19. Organic-inorganic heterojunction with P3HT and n-type 6H-SiC: Determination of the band alignment and photovoltaic properties

    Energy Technology Data Exchange (ETDEWEB)

    Dietmueller, Roland; Nesswetter, Helmut; Schoell, Sebastian; Hauer, Benedikt; Sharp, Ian David; Stutzmann, Martin [Walter Schottky Institut, Technische Universitaet Muenchen, Garching (Germany)

    2010-07-01

    The exact band alignment in organic/inorganic semiconductor heterojunctions is influenced by a variety of properties and difficult to predict. For the organic/inorganic heterojunction made of poly(3-hexylthiophene) (P3HT) and n-type 6H-SiC, the band alignment is determined via current-voltage measurements. For this purpose a model equivalent circuit, combining a thermionic emission diode and space-charge limited current effects, is proposed which describes the behavior of the heterojunction very well. From the fitting parameters, the interface barrier height of 1.1 eV between the lowest unoccupied molecular orbital (LUMO) of P3HT and the Fermi level of 6H-SiC can be determined. In addition from the maximum open circuit voltage of the diodes, a distance of 0.9 eV between the HOMO of P3HT and the conduction band (CB) of 6H-SiC can be deduced. These two values determine the Fermi level of 6H-SiC, which is about 120 meV below the CB, relative to the HOMO and LUMO of P3HT. The 6H-SiC/P3HT heterojunction exhibits an open circuit voltage of 0.55 eV at room temperature, which would make such a heterojunction a promising candidate for bulk heterojunction hybrid solar cells with 6H-SiC nanoparticles.

  20. Rapid detection of virulent protease secreted by Vibrio anguillarum by dot enzyme-linked immunosorbent assay

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Dot enzyme-linked immunosorbent assay (dot-ELISA), indirect ELISA and Western blot were performed to detect the virulent protease secreted by Vibrio anguillarum which was isolated from the diseased left-eyed flounder, Paralichthys olivaceous. Sensitivity results showed that dot-ELISA is a more sensitive, rapid and simple technique for the protease detection. The minimal detectable amount of protease is about 7 pg in the dot-ELISA test, while 7.8 ng in the indirect ELISA and 6.25 ng in the Western blot respectively. Protease could be detected 2 h after incubation of V. anguillarum in the 2216E liquid medium but enzyme activity was very low at that period.From 6 to 12 h, the amount and enzyme activity ofprotease increased markedly and reached maximum at stationary phase. Analysis of serum samples periodically collected from the infected flounders showed that after 2 h of infection by V. anguillarum, the pathogenic bacteria could be detected in the blood of the infected flounders but no protease was found. It was 5~6 h after infection that the protease was detected in blood and then the amount increased as infection advanced. Quantitative detection of protease either incubation in the medium or from the blood of infected flounders could be accomplished in virtue of positive controls of quantificational protease standards ("marker") so that the alterations of protease secretion both in vitro and in vivo could be understood generally. In addition, the indirect ELISA and dot-ELISA were also performed to detect V. anguillarum cells. Results indicated that the sensitivity of indirect ELISA to bacteria cells is higher than that of the dot-ELISA, and that the minimal detectable amount is approximately 104 cell/mL in the indirect ELISA, while 105 cell/mL in the dot-ELISA.

  1. Fossil Dot Com

    DEFF Research Database (Denmark)

    2011-01-01

    Since the start of the industrial revolution in 1800, with breakthrough innovations in iron production, textile industry and the steam engine, society has sustained incredible growth and transformation. During the 200 years, worldwide individual productivity has grown more than 32 times...... technological examples from his background as director of the innovation centre at DONG Energy, Charles Nielsen will discuss the impact of upcoming changes to the backbone of industry: the energy supply. DONG Energy has an ambitious strategy of changing the energy supply from 15% to 85% renewable energy before...

  2. The observation of scintillation in a hydrated inorganic compound: CeCl3 6H2O

    Energy Technology Data Exchange (ETDEWEB)

    Boatner, Lynn A [ORNL; Neal, John S [ORNL; Ramey, Joanne Oxendine [ORNL; Chakoumakos, Bryan C [ORNL; Custelcean, Radu [ORNL

    2013-01-01

    We have recently reported the discovery of a new family of rare-earth metal-organic single-crystal scintillators based on Ce3+ as the activator ion. Starting with the CeCl3(CH3OH)4 prototype, this family of scintillators has recently been extended to include complex metal-organic adducts produced by reacting CeCl3 with heavier organics (e.g., isomers of propanol and butanol). Some of these new rare-earth metal-organic materials incorporated waters of hydration in their structures, and the observation of scintillation in these hydrated compounds was an original finding for any solid scintillator. In the present work, we now report what is apparently the initial observation of gamma-ray-excited scintillation in an inorganic hydrated material, namely single-crystal monoclinic CeCl3 6H2O. This observation shows that the mechanisms of the various scintillation energy-transfer processes are not blocked by the presence of waters of hydration in an inorganic material and that the observation of scintillation in other hydrated inorganic compounds is not precluded.

  3. Study on formation of step bunching on 6H-SiC (0001) surface by kinetic Monte Carlo method

    Science.gov (United States)

    Li, Yuan; Chen, Xuejiang; Su, Juan

    2016-05-01

    The formation and evolution of step bunching during step-flow growth of 6H-SiC (0001) surfaces were studied by three-dimensional kinetic Monte Carlo (KMC) method and compared with the analytic model based on the theory of Burton-Cabera-Frank (BCF). In the KMC model the crystal lattice was represented by a structured mesh which fixed the position of atoms and interatomic bonding. The events considered in the model were adatoms adsorption and diffusion on the terrace, and adatoms attachment, detachment and interlayer transport at the step edges. In addition, effects of Ehrlich-Schwoebel (ES) barriers at downward step edges and incorporation barriers at upwards step edges were also considered. In order to obtain more elaborate information for the behavior of atoms in the crystal surface, silicon and carbon atoms were treated as the minimal diffusing species. KMC simulation results showed that multiple-height steps were formed on the vicinal surface oriented toward [ 1 1 bar 00 ] or [ 11 2 bar 0 ] directions. And then the formation mechanism of the step bunching was analyzed. Finally, to further analyze the formation processes of step bunching, a one-dimensional BCF analytic model with ES and incorporation barriers was used, and then it was solved numerically. In the BCF model, the periodic boundary conditions (PBC) were applied, and the parameters were corresponded to those used in the KMC model. The evolution character of step bunching was consistent with the results obtained by KMC simulation.

  4. Characterization and physical modeling of MOS capacitors in epitaxial graphene monolayers and bilayers on 6H-SiC

    Science.gov (United States)

    Winters, M.; Sveinbjörnsson, E. Ö.; Melios, C.; Kazakova, O.; Strupiński, W.; Rorsman, N.

    2016-08-01

    Capacitance voltage (CV) measurements are performed on planar MOS capacitors with an Al2O3 dielectric fabricated in hydrogen intercalated monolayer and bilayer graphene grown on 6H-SiC as a function of frequency and temperature. Quantitative models of the CV data are presented in conjunction with the measurements in order to facilitate a physical understanding of graphene MOS systems. An interface state density of order 2 ṡ 1012 eV-1 cm-2 is found in both material systems. Surface potential fluctuations of order 80-90meV are also assessed in the context of measured data. In bilayer material, a narrow bandgap of 260meV is observed consequent to the spontaneous polarization in the substrate. Supporting measurements of material anisotropy and temperature dependent hysteresis are also presented in the context of the CV data and provide valuable insight into measured and modeled data. The methods outlined in this work should be applicable to most graphene MOS systems.

  5. Synthesis and Crystal Structure of [ Cp* Ru(η6- C6H5B Ph3)

    Institute of Scientific and Technical Information of China (English)

    YIN Jun; GUAN Jin-Tao; YU Guang-Ao; LIU Sheng-Hua

    2005-01-01

    The title complex [Cp*Ru(η6-C6H5BPh3)] has been synthesized by the reaction of [Cp*Ru(H2O)(NBD)]BF4 with H2 and NaBPh4, and its crystal structure was determined by singlecrystal X-ray diffraction analysis. It crystallizes in triclinic, space group P(1) with a = 11.0610(10), b = 11.2317(10), c = 12.3633(11) (A), α = 81.419(2), β = 67.8370(10), γ = 88.370(2)°, V= 1405.9(2) (A)3,Z= 2, C34H35BRu, Mr= 555.50, Dc = 1.312 g/cm3, F(000) = 576 and μ(MoKa) = 0.577 mm-1. The final R and wR are 0.0559 and 0.1483, respectively for 4365 observed reflections with I > 2σ(Ⅰ). In the title complex, the four phenyl rings bonded to the B atom are deposited in a tetrahedral geometry,and one of the phenyl rings is η6-bonded to ruthenium.

  6. Stress Control in GaN Grown on 6H-SiC by Metalorganic Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    CHEN Yao; JIANG Yang; XU Pei-Qiang; MA Zi-Guang; WANG Xiao-Li; WANG Lu; JIA Hai-Qiang; CHEN Hong

    2011-01-01

    The strain in GaN epitaxial layers grown on 6H-SiC substrates with an AIN buffer by metalorganic chemical wpor deposition is investigated.It is found that the insertion of a graded AlGaN layer between the GaN layer and the AIN buffer can change the signs of strain.A compressive strain in an overgrown thick (2 μm) GaN layer is obtained.High-resolution x-ray diffraction, Raman spectroscopy and photoluminescence measurements are used to determine the strain state in the GaN layers.The mechanism of stress control by inserting graded AlGaN in subsequent GaN layers is discussed briefly.%@@ The strain in GaN epitaxial layers grown on 611-SiC substrates with an AIN buffer by metalorganic chemical vapor deposition is investigated.It is found that the insertion of a graded AlGaN layer between the GaN layer and the AIN buffer can change the signs of strain.A compressive strain in an overgrown thick(2μm)GaN layer is obtained.High-resolution x-ray diffraction, Raman spectroscopy and photoluminescence measurements are used to determine the strain state in the GaN layers.The mechanism of stress control by inserting graded AlGaN in subsequent GaN layers is discussed briefly.

  7. Angle-resolved inverse photoemission of the H-etched 6H-SiC(0001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Aghdassi, Nabi; Ostendorf, Ralf; Zacharias, Helmut [Physikalisches Institut, Westfaelische Wilhelms-Universitaet Muenster (Germany)

    2009-07-01

    The etching of 6H-SiC(0001) substrates in molecular hydrogen at elevated temperatures leads to an ordered silicate adlayer as it is confirmed by LEED and AES. LEED patterns clearly feature a ({radical}(3) x {radical}(3))R30 periodicity while AES spectra are evidence for the presence of Si-O bonds. The generated surfaces appear to be fully passivated and therefore stable in ambient air. After cleaning the samples by heating in UHV up to temperatures around 750 C angle-resolved inverse photoemission is performed on the SiO{sub 2}/SiC interface. The IPE spectra reveal five features above the Fermi level around 0.5 eV, 1.2 eV, 2.3 eV, 3.5 eV and 5.5 eV, respectively, which show only a weak dispersion along the {gamma} - M and {gamma} - K directions of the (1 x 1) surface Brillouin zone.

  8. Crystal structure of neptunium(V) sulfate hexahydrate, (NpO2)2SO4 . 6H2O

    International Nuclear Information System (INIS)

    Single crystals of (NpO2)2SO4 . 6H2O are obtained, and their structure is determined. The structure is built of NpO2+ dioxo cations, SO42- anions, and molecules of coordination and crystallization water. The NpO2+ ions are linked into cationic ribbons stretched along the [001] direction. In the ribbons, neptunoyl ions of one type act as monodentate ligands, whereas neptunoyl ions of the other type coordinate the neighboring neptunoyl groups by two oxygen atoms. The Np(1) and Np(2) atoms have oxygen environments in the shape of a pentagonal bipyramid whose equatorial plane consists of oxygen atoms of the neighboring dioxo cations, sulfate ions, and water molecules. The sulfate ion acts as a bidentate ligand bridging the two neighboring atoms Np(1) and Np(2). Six water molecules are revealed in the structure; one of them is a crystallization water molecule. Hydrogen bonds link cationic ribbons into a three-dimensional network

  9. Examination of Photoluminescence Temperature Dependencies in N-B Co-doped 6H-SiC

    International Nuclear Information System (INIS)

    Two overlapping photoluminescent (PL) bands with a peaks (half-width) at 1.95 eV (0.45 eV) and 2.15 eV (0.25 eV), correspondingly at 300 K, are observed in heavily B-N co-doped 6H-SiC epilayers under high-level excitation condition. The low energy band dominates at low temperatures and decreases towards 300 K which is assigned to DAP emission from the nitrogen trap to the deep boron (dB) with phonon-assistance. The 2.15 eV band slightly increases with temperature and becomes comparable with the former one at 300 K. We present a modelling comprising electron de-trapping from the N-trap, i.e. calculating trapping and de-trapping probabilities. The T-dependence of the 2.15 eV band can be explained by free electron emission from the conduction band into the dB center provided by similar phonon-assistance

  10. Damage response to irradiation temperature and ion fluence in C+-irradiated 6H-SiC

    International Nuclear Information System (INIS)

    Irradiation experiments have been performed 60 degree off the surface normal for 6H-SiC single crystals at various temperatures (185--870 K) using 550 keV C+ ions over a fluence range from 1 x 1018 to 5 x 1019 ions/m2. Atomic disorder on the Si sublattice, as determined by in-situ RBS/channeling analysis, ranged from dilute defects to complete amorphization. The critical amorphization dose of ∼0.23 dpa (on the Si sublattice) at 185 K has been determined. Asymmetric shapes in angular yield profiles across the crystallographic axis left-angle 0001 right-angle emerged above 1.5 x 1019 C+/m2 (∼0.05 dpa in the near-surface region), which might be associated with the lattice disturbance in the crystal structure. A gradual decrease in half-angular width was observed with the increase of ion fluence in the experiment. The minimum yield exhibits a rather linear relationship with ion dose at the surface. Post-irradiation annealing at the irradiation temperature 470 and 670 K. Results also show that low fluence (18 C+/m2) irradiation at 185 K followed by thermal annealing results in similar defect concentrations to irradiation at that same temperature to the same ion fluence. thus, at low fluences, the accumulated defects are in thermal equilibrium with the structure

  11. Routes to rupture and folding of graphene on rough 6H-SiC(0001 and their identification

    Directory of Open Access Journals (Sweden)

    M. Temmen

    2013-10-01

    Full Text Available Twisted few layer graphene (FLG is highly attractive from an application point of view, due to its extraordinary electronic properties. In order to study its properties, we demonstrate and discuss three different routes to in situ create and identify (twisted FLG. Single layer graphene (SLG sheets mechanically exfoliated under ambient conditions on 6H-SiC(0001 are modified by (i swift heavy ion (SHI irradiation, (ii by a force microscope tip and (iii by severe heating. The resulting surface topography and the surface potential are investigated with non-contact atomic force microscopy (NC-AFM and Kelvin probe force microscopy (KPFM. SHI irradiation results in rupture of the SLG sheets, thereby creating foldings and bilayer graphene (BLG. Applying the other modification methods creates enlarged (twisted graphene foldings that show rupture along preferential edges of zigzag and armchair type. Peeling at a folding over an edge different from a low index crystallographic direction can result in twisted BLG, showing a similar height as Bernal (or AA-stacked BLG in NC-AFM images. The rotational stacking can be identified by a significant contrast in the local contact potential difference (LCPD measured by KPFM.

  12. Quantum dots: Rethinking the electronics

    Science.gov (United States)

    Bishnoi, Dimple

    2016-05-01

    In this paper, we demonstrate theoretically that the Quantum dots are quite interesting for the electronics industry. Semiconductor quantum dots (QDs) are nanometer-scale crystals, which have unique photo physical, quantum electrical properties, size-dependent optical properties, There small size means that electrons do not have to travel as far as with larger particles, thus electronic devices can operate faster. Cheaper than modern commercial solar cells while making use of a wider variety of photon energies, including "waste heat" from the sun's energy. Quantum dots can be used in tandem cells, which are multi junction photovoltaic cells or in the intermediate band setup. PbSe (lead selenide) is commonly used in quantum dot solar cells.

  13. Electroluminescent hybrid organic/inorganic quantum dot devices

    International Nuclear Information System (INIS)

    The synthesis of PbS crystallites in aqueous solution in the presence of ethylenediaminetetraacetic acid (EDTA) has been investigated. Nanocrystalline material exhibiting charge confinement effects have been observed. The factors affecting crystallite growth, and hence the optical properties of the ultimately synthesised sample have been studied. A simple analytical model of the linear optical properties of quantum dots of finite size distribution has been developed. The model has been used in conjunction with the effective mass approximation (EMA) in order to model the optical properties of the synthesised PbS with a great deal of success. The EMA is found to limit the applicability of the optical model to samples of quantum dots consisting of larger crystallites as one would expect. Size-quantised CdSe particles have also been synthesised in aqueous solution. The same optical model successfully models the absorption spectra of these quantum dots, subject to the constraints of the EMA. Excessive scattering of light in solutions containing flocculated and/or bulk material is also found to limit the applicability of the model. The incorporation of colloidally suspended quantum dots into optoelectronic device structures has been considered. Energy level offsets between the quantum dots and host matrices have been studied and have been found to be unfavourable to the injection of electronic charge from the matrix into the dots. Alternative electroluminescent device structures in which the quantum dots are incorporated into electroluminescent host matrices which optically pump the quantum dots have therefore been proposed. Such devices have proved difficult to fabricate, eventual luminescence from quantum dot surface states having been obtained, but luminescence from the quantum dot effective bandgap not having been obtained. The scope of the project has extended to the investigation of charge injection into the quantum dot matrix materials themselves from the device

  14. Photonics of shungite quantum dots

    OpenAIRE

    Razbirin, Boris S.; Rozhkova, Natalia N.; Sheka, Elena F.

    2014-01-01

    Shungite quantum dots are associated with nanosize fragments of reduced graphene oxide similarly to synthetic graphene quantum dots thus forming a common class of GQDs. Colloidal dispersions of powdered shungite in water, carbon tetrachloride, and toluene form the ground for the GQD photonic peculiarities manifestation. Morphological study shows a steady trend of GQDs to form fractals and a drastic change in the colloids fractal structure caused by solvent was reliably established. Spectral s...

  15. Spin pumping through quantum dots

    OpenAIRE

    Rojek, Stephan; Governale, Michele; König, Jürgen

    2013-01-01

    We propose schemes for generating spin currents into a semiconductor by adiabatic or non-adiabatic pumping of electrons through interacting quantum dots. The appeal of such schemes lies in the possibility to tune the pumping characteristics via gate voltages that control the properties of the quantum dot. The calculations are based on a systematic perturbation expansion in the tunnel-coupling strength and the pumping frequency, expressed within a diagrammatic real-time technique. Special focu...

  16. Complexes of type C6H7(+)·L (L = N2 and CO2) studied by explicitly correlated coupled cluster theory.

    Science.gov (United States)

    Botschwina, Peter; Oswald, Rainer

    2012-05-28

    Complexes of the benzenium ion (C(6)H(7)(+)) with N(2) or CO(2) have been studied by explicitly correlated coupled cluster theory at the CCSD(T)-F12x (x = a, b) level [T. B. Adler et al., J. Chem. Phys. 127, 221106 (2007)] and the double-hybrid density functional B2PLYP-D [T. Schwabe and S. Grimme, Phys. Chem. Chem. Phys. 9, 3397 (2007)]. Improved harmonic vibrational wavenumbers for C(6)H(7)(+) have been obtained by CCSD(T∗)-F12a calculations with the VTZ-F12 basis set. Combining them with previous B2PLYP-D anharmonic contributions we arrive at anharmonic wavenumbers which are in excellent agreement with recent experimental data from p-H(2) matrix isolation IR spectroscopy [M. Bahou et al., J. Chem. Phys. 136, 154304 (2012)]. The energetically most favourable conformer of C(6)H(7)(+)·N(2) shows a π-bonded structure similar to C(6)H(7)(+)·Rg (Rg = Ne, Ar) [P. Botschwina and R. Oswald, J. Phys. Chem. A 115, 13664 (2011)] with D(e) ≈ 870 cm(-1). For C(6)H(7)(+)·CO(2), a slightly lower energy is calculated for a conformer with the CO(2) ligand lying in the ring-plane of the C(6)H(7)(+) moiety (D(e) ≈ 1508 cm(-1)). It may be discriminated from other conformers through a strong band predicted at 1218 cm(-1), red-shifted by 21 cm(-1) from the corresponding band of free C(6)H(7)(+). PMID:22667554

  17. Complexes of type C6H7+.L (L = N2 and CO2) studied by explicitly correlated coupled cluster theory

    Science.gov (United States)

    Botschwina, Peter; Oswald, Rainer

    2012-05-01

    Complexes of the benzenium ion (C_6 H_7^ +) with N2 or CO2 have been studied by explicitly correlated coupled cluster theory at the CCSD(T)-F12x (x = a, b) level [T. B. Adler et al., J. Chem. Phys. 127, 221106 (2007), 10.1063/1.2817618] and the double-hybrid density functional B2PLYP-D [T. Schwabe and S. Grimme, Phys. Chem. Chem. Phys. 9, 3397 (2007), 10.1039/b704725h]. Improved harmonic vibrational wavenumbers for C_6 H_7^ + have been obtained by CCSD(T*)-F12a calculations with the VTZ-F12 basis set. Combining them with previous B2PLYP-D anharmonic contributions we arrive at anharmonic wavenumbers which are in excellent agreement with recent experimental data from p-H2 matrix isolation IR spectroscopy [M. Bahou et al., J. Chem. Phys. 136, 154304 (2012), 10.1063/1.3703502]. The energetically most favourable conformer of C_6 H_7^ +.N2 shows a π-bonded structure similar to C_6 H_7^ +.Rg (Rg = Ne, Ar) [P. Botschwina and R. Oswald, J. Phys. Chem. A 115, 13664 (2011), 10.1021/jp207905t] with De ≈ 870 cm-1. For C_6 H_7^ +.CO2, a slightly lower energy is calculated for a conformer with the CO2 ligand lying in the ring-plane of the C_6 H_7^ + moiety (De ≈ 1508 cm-1). It may be discriminated from other conformers through a strong band predicted at 1218 cm-1, red-shifted by 21 cm-1 from the corresponding band of free C_6 H_7^ +.

  18. The INTEGRAL Science Data Centre

    OpenAIRE

    Beckmann, V.

    2002-01-01

    The INTEGRAL Science Data Centre (ISDC) processes, archives and distributes data from the INTEGRAL mission. At the ISDC incoming data from the satellite are processed and searched for transient sources and Gamma-Ray bursts. The data are archived and distributed to the guest observers. As soon as the data are public, any astronomer can access the data via the internet. ISDC also provides the tools which are necessary for the data analysis and offers user support concerning questions related to...

  19. Radwaste Treatment Centre Jaslovske Bohunice

    International Nuclear Information System (INIS)

    In this leaflet the Bohunice Radwaste Treatment Centre (BSC RAO) is presented. BSC RAO is designed to process and treat liquid and solid radwaste, arising from the NPP A-1 decommissioning, from NPPs V-1, V-2, and Mochovce operations, as well as institutional radwaste of diverse institutional (hospitals, research institutes) in the Slovak Republic. Transport, sorting, incineration, compacting, concentration and cementation of radwaste as well as monitoring of emission are described

  20. Fuzzy dot ideals and fuzzy dot H-ideals of BCH-algebras

    Institute of Scientific and Technical Information of China (English)

    PENG Jia-yin

    2008-01-01

    The notions of fuzzy dot ideals and fuzzy dot H-ideals in BCH-algebras are intro duced,several appropriate examples are provided,and their some properties are investigated.The relations among fuzzy ideal,fuzzy H-ideal,fuzzy dot ideal and fuzzy dot H-ideals in BCH algebras are discussed,several equivalent depictions of fuzzy dot ideal are obtained. How to deal with the homomorphic image and inverse image of fuzzy dot ideals (fuzzy dot H-ideals) are studied. The relations between a fuzzy dot ideal (fuzzy dot H-ideal) in BCH-algebras and a fuzzy dot ideal (fuzzy dot H-ideal) in the product algebra of BCH-algebras are given.

  1. The Notting Dale Urban Studies Centre

    Science.gov (United States)

    Webb, Chris; Lynas, Sue

    1976-01-01

    Founded in 1974, the Centre is one of the most intensively used resource centres in the United Kingdom. Adults and students from elementary to college level use its facilities to learn about the urban environment. (BD)

  2. SINTESIS DAN KARAKTERISASI SENYAWA OKSOTRINUKLIR [Cr3O(OOCC6H56(H2O3](NO3×nH2O

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2013-11-01

    Full Text Available Senyawa oksotrinuklir telah disintesis menggunakan kromium nitrat dan asam benzoat dalam etanol pada temperatur 80 oC selama 1 jam.Kristal senyawa oksotrinuklir hasil sintesis dikarakterisasi menggunakan spektrofotometer FTIR, 1H NMR padat, X-Ray Difraktometer, TGA, dan MS dengan teknik ionisasi dingin. Hasil penelitian menunjukkan bahwa senyawa oksotrinuklir mempunyai vibrasi yang khas pada bilangan gelombang 671 cm-1(ν Cr3-O. Identifikasi dengan spektrometer massa dalam asetonitril sebagai pelarut menunjukkan fragmentasi pada m/z: 1021.83 [Cr3O(OOCC6H56(MeCN3]+, 998,80 [Cr3O(OOCC6H56(MeCN2(H2O]+, 980,79 [Cr3O(OOCC6H56(MeCN2]+, 939,73 [Cr3O(OOCC6H56(MeCN]+. Puncak yang lebar dan besar pada spektrum 1H NMR menunjukkan bahwa kromium yang bersifat paramagnetic di dalam senyawa. Pola XRD menunjukkan bahwa senyawa oksotrinuklir adalah kristalin dan hasil termogravimetri menunjukkan senyawa oksotrinuklir stabil sampai suhu 174 oC dan mempunyai 5 mol air kristal. Dari hasil karakterisasi FTIR,1H NMR, XRD, TGA, dan MS dapat disimpulkan bahwa senyawa yang terbentuk adalah [Cr3O(OOCC6H56(H2O3](NO3×5H2O.

  3. Single to quadruple quantum dots with tunable tunnel couplings

    Energy Technology Data Exchange (ETDEWEB)

    Takakura, T.; Noiri, A.; Obata, T.; Yoneda, J.; Yoshida, K. [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Otsuka, T.; Tarucha, S. [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); RIKEN, Center for Emergent Matter Science, 3-1 Wako-shi, Saitama 351-0198 (Japan)

    2014-03-17

    We prepare a gate-defined quadruple quantum dot to study the gate-tunability of single to quadruple quantum dots with finite inter-dot tunnel couplings. The measured charging energies of various double dots suggest that the dot size is governed by the gate geometry. For the triple and quadruple dots, we study the gate-tunable inter-dot tunnel couplings. For the triple dot, we find that the effective tunnel coupling between side dots significantly depends on the alignment of the center dot potential. These results imply that the present quadruple dot has a gate performance relevant for implementing spin-based four-qubits with controllable exchange couplings.

  4. Near-infrared quantum dots for HER2 localization and imaging of cancer cells

    OpenAIRE

    Rizvi SB; Rouhi S; Taniguchi S; Yang SY; Green M; Keshtgar M; Seifalian AM

    2014-01-01

    Sarwat B Rizvi,1 Sepideh Rouhi,1 Shohei Taniguchi,2 Shi Yu Yang,1 Mark Green,2 Mo Keshtgar,1,3 Alexander M Seifalian1,3 1UCL Centre for Nanotechnology and Regenerative Medicine, University College London, 2Department of Physics, King's College London, 3Royal Free London NHS Foundation Trust Hospital, London, UK Background: Quantum dots are fluorescent nanoparticles with unique photophysical properties that allow them to be used as diagnostic, therapeutic, and theranostic agents, part...

  5. InAs/GaAs submonolayer quantum dot superluminescent diode emitting around 970 nm

    Institute of Scientific and Technical Information of China (English)

    Li Xin-Kun; Liang De-Chun; Jin Peng; An Qi; Wei Heng; Wu Jian; Wang Zhan-Guo

    2012-01-01

    According to the InAs/GaAs submonolayer quantum dot active region,we demonstrate a bent-waveguide superlnminescent diode emitting at a wavelength of around 970 nm.At a pulsed injection current of 0.5 A,the device exhibits an output power of 24 mW and an emission spectrum centred at 971 nm with a full width at half maximum of 16 nm.

  6. Engineering colloidal quantum dot solids within and beyond the mobility-invariant regime

    KAUST Repository

    Zhitomirsky, David

    2014-05-06

    © 2014 Macmillan Publishers Limited. Colloidal quantum dots are attractive materials for efficient, low-cost and facile implementation of solution-processed optoelectronic devices. Despite impressive mobilities (1-30 cm2V-1 s-1) reported for new classes of quantum dot solids, it is-surprisingly-the much lower-mobility (10-3-10-2 cm2V-1 s-1) solids that have produced the best photovoltaic performance. Here we show that it is not mobility, but instead the average spacing among recombination centres that governs the diffusion length of charges in today\\'s quantum dot solids. In this regime, colloidal quantum dot films do not benefit from further improvements in charge carrier mobility. We develop a device model that accurately predicts the thickness dependence and diffusion length dependence of devices. Direct diffusion length measurements suggest the solid-state ligand exchange procedure as a potential origin of the detrimental recombination centres. We then present a novel avenue for in-solution passivation with tightly bound chlorothiols that retain passivation from solution to film, achieving an 8.5% power conversion efficiency.

  7. RGDC Peptide Modified Quantum Dots Labelling and Imaging of Tumor Cells

    Institute of Scientific and Technical Information of China (English)

    GUO Yi; LI Chun-rong; SHEN Huai-bin; ZHANG Xue-zhong; LI Lin-song; YU Qian; XU Li

    2011-01-01

    The labelling and imaging of tumor cells were investigated via arginine-glycine-aspartic acidcysteine(RGDC) peptide-labelled quantum dots(QDs).The results show that RGDC modified QDs can label SMMC-7721 tumor cells and adhere to cellular membrane.In constrast,the unmodified QDs are mainly dispersed around the cell.We also found that the RGDC-QDs can penetrate into the cell at 2 h of incubation.After 6 h of incubation,RGDC-QDs can accumulate in a unique intracellular region.

  8. 6-Benzyl-3,4-dimethoxy-10-methylpyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H-one

    Directory of Open Access Journals (Sweden)

    Kathrin Meindl

    2009-10-01

    Full Text Available Pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H-ones such as the title compound, C24H21N3O3, can be obtained in a few minutes in a microwave-assisted three-component reaction from 2-aminopyridines, isocyanides and 2-carboxybenzaldehydes. In the title compound, the pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H-one ring system is almost planar (mean deviation 0.068 Å. The dihedral angle between the benzyl ring and the pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5(6H-one ring system is 78.2°. The crystal structure is stabilized by intermolecular C—H...O and C—H...N hydrogen bonds.

  9. Tungsten phosphanylarylthiolato complexes [W{PhP(2-SC6H4)2-kappa3S,S',P} 2] and [W{P(2-SC6H4)3-kappa4S,S',S",P}2]: synthesis, structures and redox chemistry.

    Science.gov (United States)

    Hildebrand, Alexandra; Lönnecke, Peter; Silaghi-Dumitrescu, Luminita; Hey-Hawkins, Evamarie

    2008-09-14

    PhP(2-SHC6H4)2 (PS2H2) reacts with WCl6 with reduction of tungsten to give the air-sensitive tungsten(IV) complex [W{PhP(2-SC6H4)2-kappa(3)S,S',P}2] (1). 1 is oxidised in air to [WO{PhPO(2-SC6H4)2-kappa(3)S,S',O}{PhP(2-SC6H4)2-kappa(3)S,S',P}] (2). The attempted synthesis of 2 by reaction of 1 with iodosobenzene as oxidising agent was unsuccessful. [W{P(2-SC6H4)3-kappa(4)S,S',S",P}2] (3) was formed in the reaction of P(2-SHC6H4)3 (PS3H3) with WCl6. The W(VI) complex 3 contains two PS3(3-) ligands, each coordinated in a tetradentate fashion resulting in a tungsten coordination number of eight. The reaction of 3 with AgBF4 yields the dinuclear tungsten complex [W2{P(2-SC6H4)3-kappa(4)S,S',S",P}3]BF4 (4). Complexes 1-4 were characterised by spectral methods and X-ray structure determination.

  10. Hexagonal Voids in 6H-SiC Single Crystal by PVT%PVT法生长6H-SiC单晶中平面六方空洞缺陷研究

    Institute of Scientific and Technical Information of China (English)

    李翠; 杨立文; 蒋秉轩; 杨志民

    2012-01-01

    Hexagonal voids defect was a kind of typical bulk defects in the SiC boules grown by physical vapor transport method (PVT) , which seriously affected the quality of the SiC wafers. Therefore, it is significant to study and remove the hexagonal voids to improve the wafer quality. In this paper, four SiC boules were grown by PVT method with different seed mounting methods. The characteristics of distribution and morphology and the formation of the voids in the boules were studied by means of optical microscopy. The results showed that the evaporation of back-seed was the main cause of hexagonal voids. Two reasons of back-seed evaporation were summed up: the existence of air bubbles attached to the backside surface of the seed crystal and the higher temperature in the place attached to it than the other places in the air bubbles. Dense tantalum carbide film on the backside of the seed could restrain the evaporation of back-seed. When the TaC-coated seed was fixed on the seed holder by adhesive, SiC crystal with little hexagonal voids was obtained.%平面六方空洞是SiC晶体中一种典型的体缺陷,其存在严重影响了晶片的质量.因此,研究和去除平面六方空洞缺陷对提高晶片质量有重要意义.使用物理气相输运法(physical vapor transport,PVT)制备了4块6H-SiC单晶,使用光学显微镜观察了平面六方空洞的分布和形貌特征,并研究其形成机制.结果表明,平面六方空洞的形成主要由籽晶背向分解造成的.籽晶背向分解存在两个必要条件:籽晶背面存在与其相接触的气孔;气孔内与籽晶背面相接触的区域比其他区域温度高.籽晶背面的TaC致密膜层能够抑制籽晶背面的分解.结合使用在籽晶背面生成致密TaC膜层和粘结固定两种措施,有效地抑制了籽晶的背面分解,得到了无平面六方空洞缺陷的SiC晶体.

  11. Solar and geothermal heating and cooling of the European Centre for Public Law building in Greece

    Energy Technology Data Exchange (ETDEWEB)

    Karagiorgas, M.; Mendrinos, D.; Karytsas, C. [Centre for Renewable Energy Sources, Pikermi (Greece)

    2004-04-01

    The European Centre for Public Law in Legraina near Athens in Greece is heated and cooled by a combined solar and geothermal system. The main components of the system are a saline groundwater supplying well, water storage tank for 6 h autonomy, inverter for regulating geothermal flow, heat exchanger, two electrical water source heat pumps placed in cascade, fan coils, air handling units, as well as solar air collectors for air preheating in winter. In addition, hot water is supplied to the building hostel by solar water heaters. Monitoring of the energy system during heating showed excellent energy efficiency and performance. (author)

  12. Scheduling participants of Assessment Centres

    DEFF Research Database (Denmark)

    Lysgaard, Jens; Løber, Janni

      Assessment Centres are used as a tool for psychologists and coaches to observe a number of dimensions in a person's behaviour and test his/her potential within a number of chosen focus areas. This is done in an intense course, with a number of different exercises which expose each participant......'s ability level in the chosen focus areas. The participants are observed by assessors with the purpose of gathering material for reaching a conclusion on each participant's personal profile. We consider the particular case that arises at the company Human Equity (www.humanequity.dk), where Assessment...

  13. Lateral Growth Expansion of 4H/6H-SiC m-plane Pseudo Fiber Crystals by Hot Wall CVD Epitaxy

    Science.gov (United States)

    Trunek, Andrew J.; Neudeck, Philip G.; Woodworth, Andrew A.; Powell, J. A.; Spry, David J.; Raghothamachar, Balaji; Dudley, Michael

    2011-01-01

    Lateral expansion of small mixed polytype 4H/6H-SiC slivers were realized by hot wall chemical vapor deposition (HWCVD). Small slivers cut from m-oriented ..11..00.. SiC boule slices containing regions of 4H and 6H SiC were exposed to HWCVD conditions using standard silane/propane chemistry for a period of up to eight hours. The slivers exhibited approximately 1500 microns (1.5 mm) of total lateral expansion. Initial analysis by synchrotron white beam x-ray topography (SWBXT) confirms, that the lateral growth was homoepitaxial, matching the polytype of the respective underlying region of the seed sliver.

  14. Optical Fiber Sensing Using Quantum Dots

    OpenAIRE

    Faramarz Farahi; José Luís Santos; Tito Trindade; Manuel António Martins; Pedro Jorge

    2007-01-01

    Recent advances in the application of semiconductor nanocrystals, or quantum dots, as biochemical sensors are reviewed. Quantum dots have unique optical properties that make them promising alternatives to traditional dyes in many luminescence based bioanalytical techniques. An overview of the more relevant progresses in the application of quantum dots as biochemical probes is addressed. Special focus will be given to configurations where the sensing dots are incorporated in sol...

  15. A colloidal quantum dot spectrometer

    Science.gov (United States)

    Bao, Jie; Bawendi, Moungi G.

    2015-07-01

    Spectroscopy is carried out in almost every field of science, whenever light interacts with matter. Although sophisticated instruments with impressive performance characteristics are available, much effort continues to be invested in the development of miniaturized, cheap and easy-to-use systems. Current microspectrometer designs mostly use interference filters and interferometric optics that limit their photon efficiency, resolution and spectral range. Here we show that many of these limitations can be overcome by replacing interferometric optics with a two-dimensional absorptive filter array composed of colloidal quantum dots. Instead of measuring different bands of a spectrum individually after introducing temporal or spatial separations with gratings or interference-based narrowband filters, a colloidal quantum dot spectrometer measures a light spectrum based on the wavelength multiplexing principle: multiple spectral bands are encoded and detected simultaneously with one filter and one detector, respectively, with the array format allowing the process to be efficiently repeated many times using different filters with different encoding so that sufficient information is obtained to enable computational reconstruction of the target spectrum. We illustrate the performance of such a quantum dot microspectrometer, made from 195 different types of quantum dots with absorption features that cover a spectral range of 300 nanometres, by measuring shifts in spectral peak positions as small as one nanometre. Given this performance, demonstrable avenues for further improvement, the ease with which quantum dots can be processed and integrated, and their numerous finely tuneable bandgaps that cover a broad spectral range, we expect that quantum dot microspectrometers will be useful in applications where minimizing size, weight, cost and complexity of the spectrometer are critical.

  16. Core Competencies Of A Call Centre AgentCore Competencies Of A Call Centre Agent

    OpenAIRE

    Christine White; Vera Roos

    2005-01-01

    Call centre agents are becoming increasingly important in the call centre context. They act as a contact point between the customer and the company. Call centre agents should have certain competencies to perform their duties sufficiently. Identifying competencies, required to be effective agents, will ease the task of training and recruitment. Due to the interrelatedness of the call centre agent, the management of a call centre and customers, all relevant role players’ perceptions were taken ...

  17. Quantum-dot emitters in photonic nanostructures

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Stobbe, Søren; Lodahl, Peter

    2010-01-01

    The spontaneous emission from self-assembled semiconductor quantum dots is strongly influenced by the environment in which they are placed. This can be used to determine fundamental optical properties of the quantum dots as well as to manipulate and control the quantum-dot emission itself....

  18. Beer's law in semiconductor quantum dots

    CERN Document Server

    Adamashvili, G T

    2010-01-01

    The propagation of a coherent optical linear wave in an ensemble of semiconductor quantum dots is considered. It is shown that a distribution of transition dipole moments of the quantum dots changes significantly the polarization and Beer's absorption length of the ensemble of quantum dots. Explicit analytical expressions for these quantities are presented.

  19. Perceptual centres in speech - an acoustic analysis

    Science.gov (United States)

    Scott, Sophie Kerttu

    Perceptual centres, or P-centres, represent the perceptual moments of occurrence of acoustic signals - the 'beat' of a sound. P-centres underlie the perception and production of rhythm in perceptually regular speech sequences. P-centres have been modelled both in speech and non speech (music) domains. The three aims of this thesis were toatest out current P-centre models to determine which best accounted for the experimental data bto identify a candidate parameter to map P-centres onto (a local approach) as opposed to the previous global models which rely upon the whole signal to determine the P-centre the final aim was to develop a model of P-centre location which could be applied to speech and non speech signals. The first aim was investigated by a series of experiments in which a) speech from different speakers was investigated to determine whether different models could account for variation between speakers b) whether rendering the amplitude time plot of a speech signal affects the P-centre of the signal c) whether increasing the amplitude at the offset of a speech signal alters P-centres in the production and perception of speech. The second aim was carried out by a) manipulating the rise time of different speech signals to determine whether the P-centre was affected, and whether the type of speech sound ramped affected the P-centre shift b) manipulating the rise time and decay time of a synthetic vowel to determine whether the onset alteration was had more affect on P-centre than the offset manipulation c) and whether the duration of a vowel affected the P-centre, if other attributes (amplitude, spectral contents) were held constant. The third aim - modelling P-centres - was based on these results. The Frequency dependent Amplitude Increase Model of P-centre location (FAIM) was developed using a modelling protocol, the APU GammaTone Filterbank and the speech from different speakers. The P-centres of the stimuli corpus were highly predicted by attributes of

  20. Isolation of 1,4-Li(2)-C(6)H(4) and its reaction with [(Ph(3)P)AuCl].

    Science.gov (United States)

    Flower, Kevin R; McGown, A T; Miles, Philip J; Pritchard, Robin G; Warren, John E

    2010-04-14

    The difficulty in generating 1,4-Li2-C6H4 utilising the lithium halogen exchange reaction on 1,4-Br2-C6H4, 1,4-I2-C6H4 and 1-Br-4-I-C6H4 is revisited and only on treatment of 1,4-I2-C6H4 with 2 molar equivalents of n-BuLi can 1,4-Li2-C6H4 1 be isolated in excellent yield. Treatment of 1 with two equivalents of [ClAu(PPh3)] gives [1,4-(Ph3PAu)2-C6H4] 2a in excellent yield. Subsequent treatment of 2a with 2.5 molar equivalents of PPh2Me, PPhMe2 or PMe3 affords the PPh3 substituted compounds [1,4-(LAu)2-C6H4] (L = PPh2Me 2b, PPhMe2 2c, PMe3 2d) in essentially quantitative yields. On treatment of 1,4-Br2-C6H4 or 1-Br-4-I-C6H4 with 2 molar equivalents of n-BuLi only mono-lithiation takes place to give 1-Br-4-Li-C6H4 3 as shown through the isolation of essentially 1:1 molar equivalents of Ph2PC6H4-4-Br and Ph2PBu on treatment with 2 molar equivalents of ClPPh2. Treatment of 3, prepared by lithium/iodine exchange on 1-Br-4-I-C6H4, with [ClAu(PPh3)] affords [(Ph3P)Au(C6H4-4-Br)] 4 as expected and in addition [(Ph3P)Au(n-Bu)(C6H4-4-Br)2] 5, indicating the straightforward chloride/aryl exchange at gold may proceed in competition with oxidative addition of the n-BuI, generated in the initial lithium/iodine exchange reaction, to some aurate complex Li[Au(C6H4-4-Br)2] 6 formed in situ followed by reductive elimination of Br-C6H4-4-n-Bu in a manner that mimics lithium diorganocuprate chemistry. All of the gold-containing compounds have been spectroscopically characterised by 1H and 31P-{1H} NMR and in addition compounds 2a-d and 5 by single crystal X-ray diffraction studies. The solid state structures observed for 2a-d are dictated by non-conventional hydrogen bonding and the packing requirements of the phosphine ligands. For 2a and 2b there is no close Au...Au approach, however for 2c and 2d the reduction in the number of phenyl rings allows the formation of Au...Au contacts. For 2c and 2d the extended structures appear to be helical chains with Au...Au contact parameters of 3

  1. Isolation of 1,4-Li(2)-C(6)H(4) and its reaction with [(Ph(3)P)AuCl].

    Science.gov (United States)

    Flower, Kevin R; McGown, A T; Miles, Philip J; Pritchard, Robin G; Warren, John E

    2010-04-14

    The difficulty in generating 1,4-Li2-C6H4 utilising the lithium halogen exchange reaction on 1,4-Br2-C6H4, 1,4-I2-C6H4 and 1-Br-4-I-C6H4 is revisited and only on treatment of 1,4-I2-C6H4 with 2 molar equivalents of n-BuLi can 1,4-Li2-C6H4 1 be isolated in excellent yield. Treatment of 1 with two equivalents of [ClAu(PPh3)] gives [1,4-(Ph3PAu)2-C6H4] 2a in excellent yield. Subsequent treatment of 2a with 2.5 molar equivalents of PPh2Me, PPhMe2 or PMe3 affords the PPh3 substituted compounds [1,4-(LAu)2-C6H4] (L = PPh2Me 2b, PPhMe2 2c, PMe3 2d) in essentially quantitative yields. On treatment of 1,4-Br2-C6H4 or 1-Br-4-I-C6H4 with 2 molar equivalents of n-BuLi only mono-lithiation takes place to give 1-Br-4-Li-C6H4 3 as shown through the isolation of essentially 1:1 molar equivalents of Ph2PC6H4-4-Br and Ph2PBu on treatment with 2 molar equivalents of ClPPh2. Treatment of 3, prepared by lithium/iodine exchange on 1-Br-4-I-C6H4, with [ClAu(PPh3)] affords [(Ph3P)Au(C6H4-4-Br)] 4 as expected and in addition [(Ph3P)Au(n-Bu)(C6H4-4-Br)2] 5, indicating the straightforward chloride/aryl exchange at gold may proceed in competition with oxidative addition of the n-BuI, generated in the initial lithium/iodine exchange reaction, to some aurate complex Li[Au(C6H4-4-Br)2] 6 formed in situ followed by reductive elimination of Br-C6H4-4-n-Bu in a manner that mimics lithium diorganocuprate chemistry. All of the gold-containing compounds have been spectroscopically characterised by 1H and 31P-{1H} NMR and in addition compounds 2a-d and 5 by single crystal X-ray diffraction studies. The solid state structures observed for 2a-d are dictated by non-conventional hydrogen bonding and the packing requirements of the phosphine ligands. For 2a and 2b there is no close Au...Au approach, however for 2c and 2d the reduction in the number of phenyl rings allows the formation of Au...Au contacts. For 2c and 2d the extended structures appear to be helical chains with Au...Au contact parameters of 3

  2. The new AMS control centre

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    Construction work for the future AMS control room began in November 2010 and should be finished this June. The new building, which will have been completed in record time thanks to the professionalism of the project team, will soon be ready to receive the initial data from the AMS experiment.     Luigi Scibile and Michael Poehler, from the GS department, at the AMS control centre construction site.   The Alpha Magnetic Spectrometer (AMS) is due to wing its way towards the International Space Station (ISS) on board the shuttle Discovery in April. Mainly intended for research on antimatter and dark matter, the data collected by AMS will be sent to Houston in the United States and then directly to CERN’s new Building 946. Construction work for the AMS control centre building on the Route Gentner at CERN’s Prévessin site started in November 2010 and must be completed in time to receive the first data from the spectrometer in June. “It normall...

  3. Spin centres in SiC for all-optical nanoscale quantum sensing under ambient conditions

    Science.gov (United States)

    Anisimov, A. N.; Babunts, R. A.; Kidalov, S. V.; Mokhov, E. N.; Soltamov, V. A.; Baranov, P. G.

    2016-07-01

    Level anticrossing (LAC) spectroscopy was demonstrated on a family of uniaxially oriented spin colour centres with S = 3/2 in the ground and excited states in hexagonal 4H-, 6H- and rhombic 15R- SiC polytypes. It was shown that these centres exhibit unique characteristics such as optical spin alignment up to the temperatures of 250 ◦C. A sharp variation of the IR photoluminescence intensity in the vicinity of LAC with the record contrast was observed, which can be used for a purely all-optical sensing of the magnetic field and temperature without applying radiofrequency field. A distinctive feature of the LAC signal is weak dependence on the direction of the magnetic field that allows one to monitor the LAC signals in the nonoriented systems, such as powder of SiC nanocrystals.

  4. Spin storage in quantum dot ensembles and single quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Heiss, Dominik

    2009-10-15

    This thesis deals with the investigation of spin relaxation of electrons and holes in small ensembles of self-assembled quantum dots using optical techniques. Furthermore, a method to detect the spin orientation in a single quantum dot was developed in the framework of this thesis. A spin storage device was used to optically generate oriented electron spins in small frequency selected quantum dot ensembles using circularly polarized optical excitation. The spin orientation can be determined by the polarization of the time delayed electroluminescence signal generated by the device after a continuously variable storage time. The degree of spin polarized initialization was found to be limited to 0.6 at high magnetic fields, where anisotropic effects are compensated. The spin relaxation was directly measured as a function of magnetic field, lattice temperature and s-shell transition energy of the quantum dot by varying the spin storage time up to 30 ms. Very long spin lifetimes are obtained with a lower limit of T{sub 1}=20 ms at B=4 T and T=1 K. A strong magnetic field dependence T{sub 1}{proportional_to}B{sup -5} has been observed for low temperatures of T=1 K which weakens as the temperature is increased. In addition, the temperature dependence has been determined with T{sub 1}{proportional_to}T{sup -1}. The characteristic dependencies on magnetic field and temperature lead to the identification of the spin relaxation mechanism, which is governed by spin-orbit coupling and mediated by single phonon scattering. This finding is qualitatively supported by the energy dependent measurements. The investigations were extended to a modified device design that enabled studying the spin relaxation dynamics of heavy holes in self-assembled quantum dots. The measurements show a polarization memory effect for holes with up to 0.1 degree of polarization. Furthermore, investigations of the time dynamics of the hole spin relaxation reveal surprisingly long lifetimes T{sub 1}{sup h

  5. Spin storage in quantum dot ensembles and single quantum dots

    International Nuclear Information System (INIS)

    This thesis deals with the investigation of spin relaxation of electrons and holes in small ensembles of self-assembled quantum dots using optical techniques. Furthermore, a method to detect the spin orientation in a single quantum dot was developed in the framework of this thesis. A spin storage device was used to optically generate oriented electron spins in small frequency selected quantum dot ensembles using circularly polarized optical excitation. The spin orientation can be determined by the polarization of the time delayed electroluminescence signal generated by the device after a continuously variable storage time. The degree of spin polarized initialization was found to be limited to 0.6 at high magnetic fields, where anisotropic effects are compensated. The spin relaxation was directly measured as a function of magnetic field, lattice temperature and s-shell transition energy of the quantum dot by varying the spin storage time up to 30 ms. Very long spin lifetimes are obtained with a lower limit of T1=20 ms at B=4 T and T=1 K. A strong magnetic field dependence T1∝B-5 has been observed for low temperatures of T=1 K which weakens as the temperature is increased. In addition, the temperature dependence has been determined with T1∝T-1. The characteristic dependencies on magnetic field and temperature lead to the identification of the spin relaxation mechanism, which is governed by spin-orbit coupling and mediated by single phonon scattering. This finding is qualitatively supported by the energy dependent measurements. The investigations were extended to a modified device design that enabled studying the spin relaxation dynamics of heavy holes in self-assembled quantum dots. The measurements show a polarization memory effect for holes with up to 0.1 degree of polarization. Furthermore, investigations of the time dynamics of the hole spin relaxation reveal surprisingly long lifetimes T1h in the microsecond range, therefore, comparable with electron spin

  6. Microstructural and superconducting properties of C{sub 6}H{sub 6} added bulk MgB{sub 2} superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Babaoglu, Meral G.; Safran, Serap; Cicek, Oezlem; Ag Latin-Small-Letter-Dotless-I l, Hasan; Ertekin, Ercan [Department of Physics, Faculty of Science, Ankara University, Tandogan 06100, Ankara (Turkey); Hossain, Md.Shahriar A. [Institute for Superconducting and Electronic Materials, University of Wollongong, Innovation Campus, North Wollongong, NSW 2519 (Australia); Yanmaz, Ekrem [Department of Physics, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Gencer, Ali, E-mail: gencer@science.ankara.edu.tr [Department of Physics, Faculty of Science, Ankara University, Tandogan 06100, Ankara (Turkey)

    2012-10-15

    The effect of aromatic hydrocarbon (benzene, C{sub 6}H{sub 6}) addition on lattice parameters, microstructure, critical temperature (T{sub c}), critical current density (J{sub c}) of bulk MgB{sub 2} has been studied. In this work only 2 mol% C{sub 6}H{sub 6} addition was found to be very effective in increasing the J{sub c} values, while resulting in slight reduction of the T{sub c}. J{sub c} values of 2 mol% C{sub 6}H{sub 6} added MgB{sub 2} bulks reached to 1.83 Multiplication-Sign 10{sup 6} A/cm{sup 2} at 15 K and 0 T. Microstructural analyses suggest that J{sub c} enhancement is associated with the substitution of carbon with boron and which also results in the smaller MgB{sub 2} grain size. The change in the lattice parameters or the lattice disorder is claimed as a cause of the slight reduction in the T{sub c} by carbon addition. We note that our results show the advantages of C{sub 6}H{sub 6} addition include homogeneous mixing of precursor powders, avoidance of expansive nanoadditives, production of highly reactive C, and significant enhancement in J{sub c} of MgB{sub 2}, compared to un-doped samples.

  7. Chiral Building Blocks from (+)-(S)-7,7a-Dihydro-7a-methylindane-1,5(6H)-dione (Hajos-Parrish Diketone)

    OpenAIRE

    Thiemann, Thies; Noltemeyer, Michael; de Meijere, Armin

    1997-01-01

    Transformations of (+)-(S)-7,7a-dihydro-7a-methylindane-1,5(6H)-dione (5) to non-racemic bicyclo[3.3.0]octanediones 7, 14, and 16 arid non-racemic cyclopentanones like 22 are described. Reaction of the chiral diketo aldehyde 7 with phenylhydrazine yields the corresponding angular diazatriquinene derivative 19.

  8. Fluoroantimonic acid hexahydrate (HSbF6-6H2O) catalysis: The ring-opening polymerization of epoxidized soybean oil

    Science.gov (United States)

    Ring-opening polymerization of epoxidized soybean oil (ESO) catalyzed by a super acid, fluroantimonic acid hexahydrate (HSbF6-6H2O), in ethyl acetate was conducted in an effort to develop useful biodegradable polymers. The resulting polymerized ESO (SA-RPESO) were characterized by using infrared (IR...

  9. Structures and Spectroscopic Properties Calculated for C_6H_7^+ and its Complexes with Ne, Ar, N_2, or CO_2

    Science.gov (United States)

    Botschwina, P.; Oswald, R.

    2012-06-01

    Explicitly correlated coupled cluster theory at the CCSD(T)-F12x (x = a, b) level in conjunction with the double-hybrid density functional B2PLYP-D has been employed in a study of the benzenium ion (C_6H_7^+) and its complexes with simple ligands (L = Ne, Ar, N_2, or CO_2). The ground-state rotational constants of C_6H_7^+ are predicted to be A_0 = 5445 MHz, B_0 = 5313 MHz, and C_0 = 2731 MHz. For the complexes with L = Ne, Ar or N_2, the energetically most favourable structure is of π-bonded type, but for the most strongly bound complex C_6H_7^+ ... CO_2 a conformer with the CO_2 ligand lying in the ring-plane of the C_6H_7^+ moiety is slightly lower in energy. T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys. 127, 221106 (2007) G. Knizia, T. B. Adler, and H.-J. Werner, J. Chem. Phys. 130, 054104 (2009). T. Schwabe and S. Grimme, Phys. Chem. Chem. Phys. 9, 3397 (2007). P. Botschwina and R. Oswald, J. Phys. Chem. A 115, 13664 (2011) P. Botschwina and R. Oswald, J. Chem. Phys. submitted.

  10. Segregation of Incomplete Achromatopsia and Alopecia Due to PDE6H and LPAR6 Variants in a Consanguineous Family from Pakistan

    Science.gov (United States)

    Pedurupillay, Christeen Ramane J.; Landsend, Erlend Christoffer Sommer; Vigeland, Magnus Dehli; Ansar, Muhammad; Frengen, Eirik; Misceo, Doriana; Strømme, Petter

    2016-01-01

    We report on two brothers with visual impairment, and non-syndromic alopecia in the elder proband. The parents were first-degree Pakistani cousins. Whole exome sequencing of the elder brother and parents, followed by Sanger sequencing of all four family members, led to the identification of the variants responsible for the two phenotypes. One variant was a homozygous nonsense variant in the inhibitory subunit of the cone-specific cGMP phosphodiesterase gene, PDE6H:c.35C>G (p.Ser12*). PDE6H is expressed in the cones of the retina, which are involved in perception of color vision. This is the second report of a homozygous PDE6H:c.35C>G variant causing incomplete achromatopsia (OMIM 610024), thus strongly supporting the hypothesis that loss-of-function variants in PDE6H cause this visual deficiency phenotype. The second variant was a homozygous missense substitution in the lysophosphatidic acid receptor 6, LPAR6:c.188A>T (p.Asp63Val). LPAR6 acts as a G-protein-coupled receptor involved in hair growth. Biallelic loss-of-function variants in LPAR6 cause hypotrichosis type 8 (OMIM 278150), with or without woolly hair, a form of non-syndromic alopecia. Biallelic LPAR6:c.188A>T was previously described in five families from Pakistan. PMID:27472364

  11. Centre for nuclear engineering University of Toronto annual report 1984

    International Nuclear Information System (INIS)

    The annual report of the Centre for Nuclear Engineering, University of Toronto covers the following subjects: message from the Dean; Chairman's message; origins of the centre; formation of the centre; new nuclear appointments; and activities of the centre, 1984

  12. Luminescent Surface Quaternized Carbon Dots

    KAUST Repository

    Bourlinos, Athanasios B.

    2012-01-10

    Thermal oxidation of a salt precursor made from the acid base combination of tris(hydroxymethyl)aminomethane and betaine hydrochloride results in light-emitting surface quaternized carbon dots that are water-dispersible, display anion exchange properties, and exhibit uniform size/surface charge. © 2011 American Chemical Society.

  13. On triaxial ellipsoidal quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Voon, L C Lew Yan; Willatzen, M [Mads Clausen Institute, University of Southern Denmark, Grundtvigs Alle 150, DK-6400 Soenderborg (Denmark)

    2004-02-25

    The bound-state problem for triaxial ellipsoidal infinite-barrier quantum dots has been solved. It is exactly solvable in terms of ellipsoidal coordinates and the eigenmodes are written in terms of Lame wavefunctions. The need for all eight types of functions is shown. This presents a generalization over previous work on spheres and spheroids. Splitting of degeneracy and level crossing are obtained.

  14. DOT strategies versus orbiter strategies

    NARCIS (Netherlands)

    Rutten, R.J.

    2001-01-01

    The Dutch Open Telescope is a high-resolution solar imager coming on-line at La Palma. The definition of the DOT science niche, strategies, and requirements resemble Solar Orbiter considerations and deliberations. I discuss the latter in the light of the former, and claim that multi-line observation

  15. Vertical asymmetric double quantum dots

    Science.gov (United States)

    Roßbach, R.; Reischle, M.; Beirne, G. J.; Schweizer, H.; Jetter, M.; Michler, P.

    2007-01-01

    Two layers of differently sized self-assembled InP-quantum dots (QDs) separated by a GaInP spacer layer with varying thickness were grown by metal organic vapor phase epitaxy (MOVPE). Photoluminescence measurements of the QD ensembles and of individual asymmetric double QDS show coupling due to the tunnelling of carriers.

  16. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    The extended run Uninterruptible Power Supply system (UPSs) which powered by fuel cells and supercapcitors, is a promising solution for future data centre to obtain environmentfriendly energy efficient and cost effective. There are many challenges in power electronic interface circuits, because......: • Optimized design method for dual active bridge (DAB) converter and its derived circuits; • A novel hybrid dc-dc converter and its corresponding optimal design method are proposed; • An improved dual input current-fed DC-DC converter with bidirectional power conversion ability is investigated; • Extend...... the circuit level decoupling modulation scheme into 3LNPC inverter. As to the DAB converter, through the power factor and harmonics analysis, the dominated loss factor is found in variable input voltage range. Optimized parameter choosing method is used to decide the ac inductance and switching frequency...

  17. Hyperdense dots mimicking microcalcifications : Mammographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam Hyeon; Park, Jeong Mi; Goo, Hyun Woo; Bang, Sun Woo [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    1996-12-01

    To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy.

  18. Hyperdense dots mimicking microcalcifications : Mammographic findings

    International Nuclear Information System (INIS)

    To differentiate fine hyperdense dots mimicking microcalcifications from true microcalcifications on mammography. Mammograms showing hyperdense dots in ten patients (mean age, 59 years) were evaluated. Two radiologists were asked to differentiate with the naked eye the hyperdense dots seen on ten mammograms and proven microcalcifications seen on ten mammograms. Densitometry was also performed for all lesions and the contrast index was calculated. The shape and distribution of the hyperdense dots were evaluated and enquires were made regarding any history of breast disease and corresponding treatment. Biopsies were performed for two patients with hyperdense dots. Two radiologists made correct diagnoses in 19/20 cases(95%). The contrast index was 0.10-0.88 (mean 0.58) for hyperdense dots and 0.02-0.45 (mean 0.17) for true microcalcifications. The hyperdense dots were finer and homogeneously rounder than the microcalcifications. Distribution of the hyperdense dots was more superficial in subcutaneous fat (seven cases) and subareolar area (six cases). All ten patients with hyperdense dots had history of mastitis and abscesses and had been treated by open drainage (six cases) and/or folk remedy (four cases). In eight patients, herb patches had been attached. Biopsies of hyperdense dots did not show any microcalcification or evidence of malignancy. These hyperdense dots were seen mainly in older patients. Their characteristic density, shape, distribution and clinical history makes differential diagnosis from true microcalcifications easy and could reduce unnecessary diagnostic procedures such as surgical biopsy

  19. Systematic safety evaluation on photoluminescent carbon dots

    Science.gov (United States)

    Wang, Kan; Gao, Zhongcai; Gao, Guo; Wo, Yan; Wang, Yuxia; Shen, Guangxia; Cui, Daxiang

    2013-03-01

    Photoluminescent carbon dots (C-dots) were prepared using the improved nitric acid oxidation method. The C-dots were characterized by tapping-mode atomic force microscopy, and UV-vis absorption spectroscopy. The C-dots were subjected to systematic safety evaluation via acute toxicity, subacute toxicity, and genotoxicity experiments (including mouse bone marrow micronuclear test and Salmonella typhimurium mutagenicity test). The results showed that the C-dots were successfully prepared with good stability, high dispersibility, and water solubility. At all studied C-dot dosages, no significant toxic effect, i.e., no abnormality or lesion, was observed in the organs of the animals. Therefore, the C-dots are non-toxic to mice under any dose and have potential use in fluorescence imaging in vivo, tumor cell tracking, and others.

  20. Spin transport through quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Lima, A.T. da Cunha; Anda, Enrique V. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2003-07-01

    Full text: We investigate the spin polarized transport properties of a nanoscopic device constituted by a quantum dot connected to two leads. The electrical current circulates with a spin polarization that is modulated via a gate potential that controls the intensity of the spin-orbit coupling, the Rashba effect. We study a polarized field-effect transistor when one of its parts is constituted by a small quantum dot, which energies are controlled by another gate potential operating inside the confined region. The high confinement and correlation suffered by the charges inside the dot gives rise to novel phenomena. We show that through the manipulation of the gate potential applied to the dot it is possible to control, in a very efficient way, the intensity and polarization of the current that goes along the system. Other crucial parameters to be varied in order to understand the behavior of this system are the intensity of the external applied electric and magnetic field. The system is represented by the Anderson Impurity Hamiltonian summed to a spin-orbit interaction, which describes the Rashba effect. To obtain the current of this out-of-equilibrium system we use the Keldysh formalism.The solution of the Green function are compatible with the Coulomb blockade regime. We show that under the effect of a external magnetic field, if the dot is small enough the device operates as a complete spin filter that can be controlled by the gate potential. The behavior of this device when it is injected into it a polarized current and modulated by the Rashba effect is as well studied. (author)

  1. Smart work centres in rural areas

    DEFF Research Database (Denmark)

    Lorentzen, Anne Birte

    This paper discusses the establishment of telework centres as an element in local development strategies in rural areas, with a particular view to two new telework centres in region North Denmark. The paper argues that telework centres do not represent an easy solution to problems of local...... development and environmental sustainability, and further, that technology may not even be the most important feature needed to make them function as such....

  2. Activities of Radiation Protection Centre in 2000

    CERN Document Server

    Radiat. Prot. Cent. Vilnius

    2001-01-01

    Description of the activities of Radiation Protection Centre in 2000 is presented. Radiation Protection Centre is responsible for radiation protection issues. Currently there are six departments at Radiation Protection Centre: two in Vilnius - Department of Radiation Protection Supervision and Control and Department of Programs and Expertise, and four in the districts. Brief information on subject controlled by each departments is provided focusing on main achievements and events.

  3. Elm Farm Organic Research Centre December 2006

    OpenAIRE

    Sanders, Richard; Whiltley, Andrew; Haigh, Zoe; Clarke, Sarah; Hitchings, Roger; O'Brien, Josie

    2006-01-01

    The Organic Research Centre. Elm Farm Research Centre Bulletin with Technical Updates from The Organic Advisory Service is a regular publication from The Organic Research Centre. The current issue covers: Report from 2006 Cirencester Conference; Quest for more home produced organic food; in a world where bread matters; Improving wheat with plenty of parents; Unlocking the secrets of the ancient (cereal varieties); Brain food- a good read; Not to late to protect the future: The organic...

  4. Business plan – Tennis centre modernization

    OpenAIRE

    Moravec, Martin

    2012-01-01

    The goal of this master's thesis "Business plan -- Tennis centre modernization" - is creating and writing the business plan for the reconstruction of the existing tennis centre. The theoretical part describes characteristics of small and medium sized enterprises, their meaning. Describes the necessary parts of the business plan, its possible structure. The paper involves the knowledge gained into the concrete case of the tennis centre. Describes its nowadays conditions and possible solutions....

  5. The metastable HCl · 6H2O phase – IR spectroscopy, phase transitions and kinetic/thermodynamic properties in the range 170–205 K

    Directory of Open Access Journals (Sweden)

    S. Chiesa

    2013-07-01

    Full Text Available In this laboratory study, 1 to 2 μm thick polycrystalline ice films have been grown under stirred flow reactor (SFR conditions and subsequently doped with metered amounts of HCl under static conditions. A multidiagnostic approach including FTIR absorption spectroscopy in transmission, residual gas mass spectrometry (MS and total pressure measurement was employed. Depending on the growth protocol controlling both temperature and partial pressure of HCl (PHCl, either amorphous HCl/H2O or crystalline HCl hexahydrate (HCl · 6H2O have been obtained. After controlled doping with HCl and evaporation of excess H2O from the ice film, transmission FTIR of pure HCl · 6H2O films and use of calibrated residual gas MS enabled the measurement of differential (peak IR cross sections at several mid-IR frequencies (σ = (6.5 ± 1.9 × 10-19 cm2 molec-1 at 1635 cm-1 as an example. Two types of kinetic experiments on pure HCl · 6H2O have been performed under SFR conditions: (a evaporation of HCl · 6H2O under H2O-poor conditions over a narrow T range, and (b observation of the phase transition from crystalline HCl · 6H2O to amorphous HCl/H2O under H2O-rich conditions at increasing T. The temperature dependence of the zero-order evaporation flux of HCl in pure HCl · 6H2O monitored at 3426 cm-1 led to log(Jev molec cm-2s-1= (36.34 ± 3.20 - (80 810 ± 5800/2.303RT with R=8.312 JK−1 mol-1. HCl · 6H2O has a significant intrinsic kinetic barrier to HCl evaporation of 15.1 kJ mol-1 in excess of the HCl sublimation enthalpy of 65.8 kJ mol-1 at 200 K but is kinetically unstable (metastable at typical UT/LS conditions of HCl partial pressure (P(HCl and temperature. Water-rich HCl · 6H2O undergoes a facile phase transition from crystalline to the amorphous/ supercooled/disordered state easily observable at T≥ 195 K under both static and SFR conditions. This corresponds to low P(HCl in the neighborhood of 10-7 Torr that also prevails at the Upper Troposphere

  6. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  7. Interfacial transformations in the a-SiC/a-Si/6H-SiC structure caused by high-temperature (1500°C) annealing

    Science.gov (United States)

    Ivanov, P. A.; Samsonova, T. P.

    2008-07-01

    We have studied the reactions that take place at interfaces in an a-SiC/a-Si/6H-SiC sandwich structure, which was obtained by the sequential deposition of amorphous silicon (a-Si) and amorphous silicon carbide (a-SiC) onto a 6H-SiC substrate by ion sputtering in vacuum and then annealed at 1500°C (i.e., above the melting point of silicon). It is shown that the annealing leads to complete îdissipationî of the silicon film in SiC, probably as a result of the dissolution of carbon in the silicon melt and the diffusion of silicon into SiC.

  8. Three-dimensional electron-positron momentum distribution of O{sup 3+}-irradiated 6H SiC using two positron spectroscopy techniques simultaneously

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Christopher; Burggraf, Larry; Petrosky, James [Air Force Institute of Technology, AFIT/ENP, 2950 Hobson Way, Wright-Patterson Air Force Base, OH 45433 (United States); Adamson, Paul, E-mail: christopher.williams@afit.edu [Stockpile Research, Development and Engineering Division, Office of Defense Programs, National Nuclear Security Administration, 1000 Independence Ave SW, Washington, DC 20585 (United States)

    2011-01-01

    A three-dimensional (3D) positron annihilation spectroscopy system (3DPASS) capable of determining 3D electron-positron (e{sup -}-e{sup +}) momentum densities from measurements of deviations from co-linearity and energies of photons from e{sup -}-e{sup +} annihilation events was employed to examine the effects of O-atom defects in 6H SiC. Three-dimensional momentum datasets were determined for 6H SiC irradiated with 24 MeV O{sup 3+} ions. Angular correlation of annihilation radiation (ACAR) and coincidence Doppler-broadening of annihilation radiation (CDBAR) analyses are presented. In addition, a novel technique is illustrated for analyzing 3D momentum datasets in which the parallel momentum component, p{sub ||} (obtained from the CDBAR measurement) is selected for annihilation events that possess a particular perpendicular momentum component, p{sub -} observed in the 2D ACAR spectrum.

  9. Characterization of 6H-SiC JFET Integrated Circuits Over A Broad Temperature Range from -150 C to +500 C

    Science.gov (United States)

    Neudeck, Philip G.; Krasowski, Michael J.; Chen, Liang-Yu; Prokop, Norman F.

    2009-01-01

    The NASA Glenn Research Center has previously reported prolonged stable operation of simple prototype 6H-SiC JFET integrated circuits (logic gates and amplifier stages) for thousands of hours at +500 C. This paper experimentally investigates the ability of these 6H-SiC JFET devices and integrated circuits to also function at cold temperatures expected to arise in some envisioned applications. Prototype logic gate ICs experimentally demonstrated good functionality down to -125 C without changing circuit input voltages. Cascaded operation of gates at cold temperatures was verified by externally wiring gates together to form a 3-stage ring oscillator. While logic gate output voltages exhibited little change across the broad temperature range from -125 C to +500 C, the change in operating frequency and power consumption of these non-optimized logic gates as a function of temperature was much larger and tracked JFET channel conduction properties.

  10. Characterization of molecular beam epitaxy grown β-Nb2N films and AlN/β-Nb2N heterojunctions on 6H-SiC substrates

    Science.gov (United States)

    Nepal, Neeraj; Katzer, D. Scott; Meyer, David J.; Downey, Brian P.; Wheeler, Virginia D.; Storm, David F.; Hardy, Matthew T.

    2016-02-01

    β-Nb2N films and AlN/β-Nb2N heterojunctions were grown by molecular beam epitaxy (MBE) on 6H-SiC. The epitaxial nature and β-Nb2N phase were determined by symmetric and asymmetric high-resolution X-ray diffraction (HRXRD) measurements, and were confirmed by grazing incidence diffraction measurements using synchrotron photons. Measured lattice parameters and the in-plane stress of β-Nb2N on 6H-SiC were c = 5.0194 Å, a = 3.0558 Å, and 0.2 GPa, respectively. The HRXRD, transmission electron microscopy, and Raman spectroscopy revealing epitaxial growth of AlN/β-Nb2N heterojunctions have identical orientations with the substrate, abrupt interfaces, and bi-axial stress of 0.88 GPa, respectively. The current finding opens up possibilities for the next generation of high-power devices that cannot be fabricated at present.

  11. NV centers in 3 C ,4 H , and 6 H silicon carbide: A variable platform for solid-state qubits and nanosensors

    Science.gov (United States)

    von Bardeleben, H. J.; Cantin, J. L.; Csóré, A.; Gali, A.; Rauls, E.; Gerstmann, U.

    2016-09-01

    The outstanding magneto-optical properties of the nitrogen-vacancy (NV) center in diamond have stimulated the search for similar systems. We show here that NV triplet centers can also be generated in all the main SiC polytypes. We have identified by electron paramagnetic resonance spectroscopy and first-principles calculations the axial NV- pairs in 3 C ,4 H , and 6 H SiC, showing polytype and lattice site-specific magnetic and optical properties. We demonstrate very efficient room-temperature spin polarization of the ground state upon near infrared optical excitation for the NV center in 3 C SiC and axial NV centers in the hexagonal (4 H ,6 H ) polytypes; the signals of basal pairs are much lower in intensity. Axial NV centers in hexagonal SiC polytypes and thus constitute unidirectional ensembles which may be useful in nanosensing applications.

  12. The European NEO Coordination Centre

    Science.gov (United States)

    Perozzi, E.; Borgia, B.; Micheli, M.

    An operational approach to NEO (Near-Earth Object) hazard monitoring has been developed at European level within the framework of the Space Situational Awareness Program (SSA) of the European Space Agency (ESA). Through federating European assets and profiting of the expertise developed in European Universities and Research Centers, it has been possible to start the deployment of the so-called SSA NEO Segment. This initiative aims to provide a significant contribution to the worldwide effort to the discovery, follow-up and characterization of the near-Earth object population. A major achievement has been the inauguration in May 2013 of the ESA NEO Coordination Centre located at ESRIN (Frascati, Italy). The goal of the NEOCC Precursor Service operations is twofold: to make available updated information on the NEO population and the associated hazard and to contribute to optimize the NEO observational efforts. This is done by maintaining and improving a Web Portal publicly available at http://neo.ssa.esa.int and by performing follow-up observations through a network of collaborating telescopes and facilities. An overview of the SSA-NEO System and a summary of the first two years of NEOCC operations is presented.

  13. Laparoscopic adrenalectomy: Single centre experience.

    LENUS (Irish Health Repository)

    O'Farrell, N J

    2012-02-01

    BACKGROUND: Laparoscopic adrenalectomy is an attractive alternative to the traditional open approach in the surgical excision of an adrenal gland. It has replaced open adrenalectomy in our institution and we review our experience to date. METHODS: All cases of laparoscopic adrenalectomies in our hospital over eight years (from 2001 to May 2009) were retrospectively reviewed. Patient demographics, diagnosis, length of hospital stay, histology and all operative and post-operative details were evaluated. RESULTS: Fifty-five laparoscopic adrenalectomies (LA) were performed on 51 patients over eight years. The mean age was 48 years (Range 16-86 years) with the male: female ratio 1:2. Twenty-three cases had a right adrenalectomy, 24 had a left adrenalectomy and the remaining four patients had bilateral adrenalectomies. 91% were successfully completed laparoscopically with five converted to an open approach. Adenomas (functional and non functional) were the leading indication for LA, followed by phaeochromocytomas. Other indications for LA included Cushing\\'s disease, adrenal malignancies and rarer pathologies. There was one mortality from necrotising pancreatitis following a left adrenalectomy for severe Cushing\\'s disease, with subsequent death 10 days later. CONCLUSION: Laparoscopic adrenalectomy is effective for the treatment of adrenal tumours, fulfilling the criteria for the ideal minimally invasive procedure. It has replaced the traditional open approach in our centre and is a safe and effective alternative. However, in the case of severe Cushing\\'s disease, laparoscopic adrenalectomy has the potential for significant adverse outcomes and mortality.

  14. Optical spectroscopy and degradation behavior of ZnGeF{sub 6}·6H{sub 2}O:Mn{sup 4+} red-emitting phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Ryosuke; Adachi, Sadao, E-mail: adachi@el.gunma-u.ac.jp

    2015-06-15

    We report on a method of synthesizing Mn{sup 4+}-activated ZnGeF{sub 6}·6H{sub 2}O hexahydrate red phosphor by the chemical reaction and its photo-induced degradation behavior. The structural and optical properties of ZnGeF{sub 6}·6H{sub 2}O:Mn{sup 4+} are investigated using X-ray diffraction measurement, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, PL decay measurement, diffuse reflectance measurement, and electron spin resonance (ESR) spectroscopy. The present hexahydrate phosphor exhibits the sharp red emission lines typically observed in various Mn{sup 4+}-activated phosphors. However, the phosphor shows remarkable PL intensity degradation under Xe lamp exposure for a few minutes or coherent laser beam irradiation at different wavelengths. Its degree is in the order of Ar{sup +} (488 nm)>He–Cd (325 nm)>He–Ne laser (632.8 nm). The photo-induced degradation mechanism is explained by a change in the valence state of manganese ions from Mn{sup 4+} to Mn{sup 5+} by the photooxidation (Mn{sup 4+}→Mn{sup 5+}) or disproportionation reaction (2Mn{sup 4+}→Mn{sup 3+}+Mn{sup 5+}). The ESR measurement confirms the decreased Mn{sup 4+} spin density in the sample exposed with Xe lamp after Xe lamp exposure for 5 min. The photo-induced degradation is concluded to universally occur in A{sup II}B{sup IV}F{sub 6}·6H{sub 2}O:Mn{sup 4+} hexahydrate phosphors. - Highlights: • A simple method was developed for synthesizing ZnGeF{sub 6}·6H{sub 2}O:Mn{sup 4+} phosphor. • Structural and luminescent properties of this phosphor were clarified. • New photo-induced degradation phenomenon was observed. • Possible degradation mechanism in this unique phosphor was proposed.

  15. The spin relaxation of nitrogen donors in 6H SiC crystals as studied by the electron spin echo method

    Science.gov (United States)

    Savchenko, D.; Shanina, B.; Kalabukhova, E.; Pöppl, A.; Lančok, J.; Mokhov, E.

    2016-04-01

    We present the detailed study of the spin kinetics of the nitrogen (N) donor electrons in 6H SiC wafers grown by the Lely method and by the sublimation "sandwich method" (SSM) with a donor concentration of about 1017 cm-3 at T = 10-40 K. The donor electrons of the N donors substituting quasi-cubic "k1" and "k2" sites (Nk1,k2) in both types of the samples revealed the similar temperature dependence of the spin-lattice relaxation rate (T1-1), which was described by the direct one-phonon and two-phonon processes induced by the acoustic phonons proportional to T and to T9, respectively. The character of the temperature dependence of the T1-1 for the donor electrons of N substituting hexagonal ("h") site (Nh) in both types of 6H SiC samples indicates that the donor electrons relax through the fast-relaxing centers by means of the cross-relaxation process. The observed enhancement of the phase memory relaxation rate (Tm-1) with the temperature increase for the Nh donors in both types of the samples, as well as for the Nk1,k2 donors in Lely grown 6H SiC, was explained by the growth of the free electron concentration with the temperature increase and their exchange scattering at the N donor centers. The observed significant shortening of the phase memory relaxation time Tm for the Nk1,k2 donors in the SSM grown sample with the temperature lowering is caused by hopping motion of the electrons between the occupied and unoccupied states of the N donors at Nh and Nk1,k2 sites. The impact of the N donor pairs, triads, distant donor pairs formed in n-type 6H SiC wafers on the spin relaxation times was discussed.

  16. Synthesis of 2,3-Dimethoxy-7-methyl-7,12-dihydro-6H-[1]-benzofuro-[2,3-c]-[1]-benzazepin-6,12-dione

    Directory of Open Access Journals (Sweden)

    Karla-Sue C. Marriott

    2002-03-01

    Full Text Available Treatment of 5,6-dimethoxy-2-(methylphenylcarbamoyl-benzofuran-3-carboxylic acid with PPA yielded 2,3-dimethoxy-7-methyl-7,12-dihydro-6H-[1]-benzofuro-[2,3-c]-[1]-benzazepin-6,12-dione. The analogous 2-[(5,6-dimethoxybenzofuran-2-carbonylmethylamino]benzoic acid was resistant to cyclization, whereas 2-[(6-methoxybenzofuran-2-carbonyl-amino]benzoic acid underwent cyclization to the corresponding 3,1-benzoxazin-4-one.

  17. A Facile Synthesis of 2, 7-Diaminothieno[2, 3-d:5,4-d]- dipyrimidine-4, 5(3H, 6H)diones

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    2, 7-Diaminothieno[2, 3-d:5, 4-d]dipyrimidine-4, 5(3H, 6H)diones 4 were synthesized by a facile synthetic method, which includes bis-aza-Wittig reaction of bis-iminophosphorane 1with aromatic isocyanate to give bis-carbodiimide 2 and subsequent reaction of 2 with various dialkylamine in the presence of solid K2CO3 or EtONa.

  18. Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C6H10O Cyclohexanone (EVLM1111, LB5654_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Trichloromethane CHCl3 + C6H10O Cyclohexanone (EVLM1111, LB5654_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  19. Synthesis and Crystal Structure of Chloro(p-toluidine)[4-(p-tolyl)imino-2-pentanone-3-oximato]-palladium( Ⅱ ), PdCl(p-CH3C6H4NH2)(p-CH3C6H4-iai)

    Institute of Scientific and Technical Information of China (English)

    冯云龙; 刘世雄

    2003-01-01

    The title complex chloro(p-toluidine)[4-(p-tolyl)imino-2-pentanone-3-oximato]-palladium( Ⅱ ), PdCl(p-CH3C6H4NH2)(p-CH3C6H4-iai), C19H22ClN3O2Pd, (p-CH3C6H4NH2 and p-CH3C6H4-iai- are p-toluidine and the anion of 4-(p-tolyl)imino-2-pentanone-3-oximato, respectively), crystallizes in the monoclinic system, space group C2/c with a = 26.082(5), b = 13.521(3),c = 12.578(3) (A), β= 112.18(3)°, Mr = 466.25, V= 4108(2) (A)3, Dc = 1.508 g/cm3, F(000) = 1888,μ(MoKα) = 1.051 mm-1, Z = 8, the final R = 0.0368 and wR = 0.0855 for 3243 observed reflections (Ⅰ≥ 2σ(Ⅰ)). The coordination environment around Pd is a distorted PdClN3 square-plane composed of imino- and oximo-nitrogen from the Schiff base ligand of p-CH3C6H4-iai-, and amino-nitrogen from p-toluidine and chlorine atom.

  20. Oil Trading Centre to Reopen in Shanghai

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Chinese oil companies will likely resume activities at the oil trading centre in Shanghai this year, a move to further liberalize the once tightly controlled oil market. The centre will trade forward contracts for refined oil products,including gasoline, diesel oil, kerosene and fuel oil, industrial sources said.

  1. Danish Anaesthesia Allergy Centre - preliminary results

    DEFF Research Database (Denmark)

    Garvey, L H; Roed-Petersen, J; Menné, T;

    2001-01-01

    BACKGROUND: Anaphylactoid reactions in anaesthesia are rare and should ideally be investigated in specialist centres. At Gentofte University Hospital, we established such a centre in 1998 as a joint venture between the Departments of Anaesthesiology and Dermatology. We present the methodology...

  2. Neighbourhood Centres – Organisation, Management and Finance

    DEFF Research Database (Denmark)

    Larsen, Jacob Norvig

    From the late 1990s neighbourhood centres were brought to the fore of public urban regen-eration policy, because they were seen as a means to accelerate the formation of social capital in deprived urban neighbourhoods. A number of such local community centres were established with substantial pub...

  3. Features of the seasonal variation of the semidiurnal, terdiurnal and 6-h components of ozone heating evaluated from Aura/MLS observations

    Directory of Open Access Journals (Sweden)

    J. Xu

    2012-02-01

    Full Text Available This paper presents the thermal forcing of the semidiurnal, terdiurnal, and 6-h components of the migrating tide induced by ozone heating in stratosphere and lower mesosphere. The heating as a function of local time is determined from the global ozone observed by the Microwave Limb Sounder on the Aura satellite. The harmonic components of the heating rates of the semidiurnal, terdiurnal and the 6-h periodicities are calculated using the Strobel/Zhu parameterized model and then decomposed into Hough modes. Seasonal variations of each harmonic component and its Hough modes are presented. For all three tidal components, the majority of the annual mean O3 heating projects onto symmetric modes. The semiannual variation is a prominent signal in almost all of the symmetric Hough modes near the stratopause. The strongest annual variation takes place in the asymmetric modes. The results also show that, during the solstice season, the maximum forcing of the diurnal and terdiurnal component occurs in the summer hemisphere while the maximum forcing of the semidiurnal and 6-h components occurs in the winter hemisphere. The global mean ozone density and the tidal components of the ozone heating rate are different between December–January and June–July. The asymmetry in the heating is primarily due to the 6.6% annual variation in the solar energy input into the Earth's atmosphere due to the annual variation of the Sun-Earth distance.

  4. Features of the seasonal variation of the semidiurnal, terdiurnal and 6-h components of ozone heating evaluated from Aura/MLS observations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Jiang, G.; Yuan, W.; Gao, H. [Chinese Academy of Sciences, Beijing (China). State Key Lab. of Space Weather; Smith, A.K. [National Center for Atmospheric Research, Boulder, CO (United States). Atmospheric Chemistry Div.

    2012-07-01

    This paper presents the thermal forcing of the semidiurnal, terdiurnal, and 6-h components of the migrating tide induced by ozone heating in stratosphere and lower mesosphere. The heating as a function of local time is determined from the global ozone observed by the Microwave Limb Sounder on the Aura satellite. The harmonic components of the heating rates of the semidiurnal, terdiurnal and the 6-h periodicities are calculated using the Strobel/Zhu parameterized model and then decomposed into Hough modes. Seasonal variations of each harmonic component and its Hough modes are presented. For all three tidal components, the majority of the annual mean O{sub 3} heating projects onto symmetric modes. The semiannual variation is a prominent signal in almost all of the symmetric Hough modes near the stratopause. The strongest annual variation takes place in the asymmetric modes. The results also show that, during the solstice season, the maximum forcing of the diurnal and terdiurnal component occurs in the summer hemisphere while the maximum forcing of the semidiurnal and 6-h components occurs in the winter hemisphere. The global mean ozone density and the tidal components of the ozone heating rate are different between December-January and June-July. The asymmetry in the heating is primarily due to the 6.6% annual variation in the solar energy input into the Earth's atmosphere due to the annual variation of the Sun-Earth distance. (orig.)

  5. Face-capping μ3-BO in B6(BO)7-: boron oxide analogue of B6H7- with rhombic 4c-2e bonds.

    Science.gov (United States)

    Guo, Jin-Chang; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-Dian

    2013-11-14

    Using the first-principle approaches, we predict a B6(BO)7(-) cluster with a face-capping μ(3)-BO, which is the boron oxide analogue of closo-B6H7(-) with a face-capping μ(3)-H. Detailed topological analysis of electron density clearly reveals the existence of three rhombic 4c-2e bonds around the B/H apex in both C3v B6(BO)7(-) and C3v B6H7(-), which possesses similar electron densities at their bond and ring critical points. The adaptive natural density partitioning (AdNDP) analysis provides a direct and visual picture of the B-B-B-B/H 4c-2e bonds for the first time. Adiabatic and vertical electron detachment energies of the concerned monoanions are calculated to facilitate their future photoelectron spectroscopy measurements and characterizations. The presence of the B6(BO)7(-) and B6H7(-) clusters extends the BO/H isolobal analogy to the whole μ(n)-BO/H series (n = 1, 2, and 3) and enriches the chemistry of boronyl. PMID:24147988

  6. Structural change induced by thermal annealing of red-light-emitting ZnSnF6 • 6H2O:Mn4+ hexahydrate phosphor

    Science.gov (United States)

    Hoshino, Ryosuke; Nakamura, Toshihiro; Adachi, Sadao

    2016-05-01

    Effects of thermal annealing on the red-emitting ZnSnF6 • 6H2O:Mn4+ hexahydrate phosphor properties were investigated using X-ray diffraction measurement (XRD), photoluminescence (PL) analysis, and Raman scattering spectroscopy. Thermal annealing was performed at T a = 50 to 400 °C in air for 1 h. Mn4+-related red emission wavelengths were redshifted about 5 nm after annealing at T a ≥ 200 °C with greatly decreased emission intensities. This change in PL spectral feature was attributed to the dehydration of the hexahydrate phosphor, supported by the XRD and Raman scattering results. The XRD and PL intensity analyses determined thermal decomposition energies of ˜0.3 eV from the ZnSnF6 • 6H2O hexahydrate to anhydrate and of ˜0.9 eV from the ZnSnF6 anhydrate to metallic fluorid/oxide (ZnF2/SnO2). A comparative discussion was given on the PL properties of two different Mn4+-activated phosphors, Ba-IV-F6:Mn4+ anhydrate and Zn-IV-F6 • 6H2O:Mn4+ hexahydrate phosphors with IV = Si, Ge, and Sn.

  7. Constructions from Dots and Lines

    CERN Document Server

    Rodriguez, Marko A

    2010-01-01

    A graph is a data structure composed of dots (i.e. vertices) and lines (i.e. edges). The dots and lines of a graph can be organized into intricate arrangements. The ability for a graph to denote objects and their relationships to one another allow for a surprisingly large number of things to be modeled as a graph. From the dependencies that link software packages to the wood beams that provide the framing to a house, most anything has a corresponding graph representation. However, just because it is possible to represent something as a graph does not necessarily mean that its graph representation will be useful. If a modeler can leverage the plethora of tools and algorithms that store and process graphs, then such a mapping is worthwhile. This article explores the world of graphs in computing and exposes situations in which graphical models are beneficial.

  8. The role of the sexual assault centre.

    LENUS (Irish Health Repository)

    Eogan, Maeve

    2013-02-01

    Sexual Assault Centres provide multidisciplinary care for men and women who have experienced sexual crime. These centres enable provision of medical, forensic, psychological support and follow-up care, even if patients chose not to report the incident to the police service. Sexual Support Centres need to provide a ring-fenced, forensically clean environment. They need to be appropriately staffed and available 24 hours a day, 7 days a week to allow prompt provision of medical and supportive care and collection of forensic evidence. Sexual Assault Centres work best within the context of a core agreed model of care, which includes defined multi-agency guidelines and care pathways, close links with forensic science and police services, and designated and sustainable funding arrangements. Additionally, Sexual Assault Centres also participate in patient, staff and community education and risk reduction. Furthermore, they contribute to the development, evaluation and implementation of national strategies on domestic, sexual and gender-based violence.

  9. Photoactivation of silicon quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, R., E-mail: rossl@ualberta.c [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); McFarlane, S. [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Rodriguez Nunez, J.R. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Wang, X.Y. [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Veinot, J.G.C. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Meldrum, A. [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada)

    2011-07-15

    We show that free-standing silicon quantum dots (QDs) can be photoactivated by blue or UV optical irradiation. The luminescence intensity increases by an order of magnitude for irradiation times of several minutes under moderate optical power. The cut-off energy for photoactivation is between 2.1 and 2.4 eV, not very different from the activation energy for hydrogen dissociation from bulk silicon surfaces. We propose the mechanism for this effect is associated with silicon-hydride bond breaking and the subsequent oxidation of dangling bonds. This phenomenon could be used to 'write' luminescent quantum dots into pre-determined arrays. - Research highlights: {yields}Laser light causes increased photoluminescence intensity in silicon quantum dots. {yields} The photoactivation process is effective for wavelengths of 514 nm and shorter. {yields} Hydrogen bound to the Si-QDs is replaced by oxygen in a two-step process. {yields} Patterning is possible but limited by physical dispersion of Si-QDs.

  10. Few-electron quantum dots

    International Nuclear Information System (INIS)

    We review some electron transport experiments on few-electron, vertical quantum dot devices. The measurement of current versus source-drain voltage and gate voltage is used as a spectroscopic tool to investigate the energy characteristics of interacting electrons confined to a small region in a semiconducting material. Three energy scales are distinguished: the single-particle states, which are discrete due to the confinement involved; the direct Coulomb interaction between electron charges on the dot; and the exchange interaction between electrons with parallel spins. To disentangle these energies, a magnetic field is used to reorganize the occupation of electrons over the single-particle states and to induce changes in the spin states. We discuss the interactions between small numbers of electrons (between 1 and 20) using the simplest possible models. Nevertheless, these models consistently describe a large set of experiments. Some of the observations resemble similar phenomena in atomic physics, such as shell structure and periodic table characteristics, Hund's rule, and spin singlet and triplet states. The experimental control, however, is much larger than for atoms: with one device all the artificial elements can be studied by adding electrons to the quantum dot when changing the gate voltage. (author)

  11. Near-infrared quantum dots for HER2 localization and imaging of cancer cells

    Directory of Open Access Journals (Sweden)

    Rizvi SB

    2014-03-01

    Full Text Available Sarwat B Rizvi,1 Sepideh Rouhi,1 Shohei Taniguchi,2 Shi Yu Yang,1 Mark Green,2 Mo Keshtgar,1,3 Alexander M Seifalian1,3 1UCL Centre for Nanotechnology and Regenerative Medicine, University College London, 2Department of Physics, King's College London, 3Royal Free London NHS Foundation Trust Hospital, London, UK Background: Quantum dots are fluorescent nanoparticles with unique photophysical properties that allow them to be used as diagnostic, therapeutic, and theranostic agents, particularly in medical and surgical oncology. Near-infrared-emitting quantum dots can be visualized in deep tissues because the biological window is transparent to these wavelengths. Their small sizes and free surface reactive groups that can be conjugated to biomolecules make them ideal probes for in vivo cancer localization, targeted chemotherapy, and image-guided cancer surgery. The human epidermal growth factor receptor 2 gene (HER2/neu is overexpressed in 25%–30% of breast cancers. The current methods of detection for HER2 status, including immunohistochemistry and fluorescence in situ hybridization, are used ex vivo and cannot be used in vivo. In this paper, we demonstrate the application of near-infrared-emitting quantum dots for HER2 localization in fixed and live cancer cells as a first step prior to their in vivo application. Methods: Near-infrared-emitting quantum dots were characterized and their in vitro toxicity was established using three cancer cell lines, ie, HepG2, SK-BR-3 (HER2-overexpressing, and MCF7 (HER2-underexpressing. Mouse antihuman anti-HER2 monoclonal antibody was conjugated to the near-infrared-emitting quantum dots. Results: In vitro toxicity studies showed biocompatibility of SK-BR-3 and MCF7 cell lines with near-infrared-emitting quantum dots at a concentration of 60 µg/mL after one hour and 24 hours of exposure. Near-infrared-emitting quantum dot antiHER2-antibody bioconjugates successfully localized HER2 receptors on SK-BR-3 cells

  12. Charge State Hysteresis in Semiconductor Quantum Dots

    OpenAIRE

    Yang, C. H.; Rossi, A; Lai, N. S.; Leon, R.; Lim, W. H.; Dzurak, A.S.

    2014-01-01

    Semiconductor quantum dots provide a two-dimensional analogy for real atoms and show promise for the implementation of scalable quantum computers. Here, we investigate the charge configurations in a silicon metal-oxide-semiconductor double quantum dot tunnel coupled to a single reservoir of electrons. By operating the system in the few-electron regime, the stability diagram shows hysteretic tunnelling events that depend on the history of the dots charge occupancy. We present a model which acc...

  13. Resonant electron transfer between quantum dots

    OpenAIRE

    Openov, Leonid A.

    1999-01-01

    An interaction of electromagnetic field with a nanostructure composed of two quantum dots is studied theoretically. An effect of a resonant electron transfer between the localized low-lying states of quantum dots is predicted. A necessary condition for such an effect is the existence of an excited bound state whose energy lies close to the top of the barrier separating the quantum dots. This effect may be used to realize the reversible quantum logic gate NOT if the superposition of electron s...

  14. Optical Fiber Sensing Using Quantum Dots

    Directory of Open Access Journals (Sweden)

    Faramarz Farahi

    2007-12-01

    Full Text Available Recent advances in the application of semiconductor nanocrystals, or quantumdots, as biochemical sensors are reviewed. Quantum dots have unique optical properties thatmake them promising alternatives to traditional dyes in many luminescence basedbioanalytical techniques. An overview of the more relevant progresses in the application ofquantum dots as biochemical probes is addressed. Special focus will be given toconfigurations where the sensing dots are incorporated in solid membranes and immobilizedin optical fibers or planar waveguide platforms.

  15. Big Surveys, Big Data Centres

    Science.gov (United States)

    Schade, D.

    2016-06-01

    Well-designed astronomical surveys are powerful and have consistently been keystones of scientific progress. The Byurakan Surveys using a Schmidt telescope with an objective prism produced a list of about 3000 UV-excess Markarian galaxies but these objects have stimulated an enormous amount of further study and appear in over 16,000 publications. The CFHT Legacy Surveys used a wide-field imager to cover thousands of square degrees and those surveys are mentioned in over 1100 publications since 2002. Both ground and space-based astronomy have been increasing their investments in survey work. Survey instrumentation strives toward fair samples and large sky coverage and therefore strives to produce massive datasets. Thus we are faced with the "big data" problem in astronomy. Survey datasets require specialized approaches to data management. Big data places additional challenging requirements for data management. If the term "big data" is defined as data collections that are too large to move then there are profound implications for the infrastructure that supports big data science. The current model of data centres is obsolete. In the era of big data the central problem is how to create architectures that effectively manage the relationship between data collections, networks, processing capabilities, and software, given the science requirements of the projects that need to be executed. A stand alone data silo cannot support big data science. I'll describe the current efforts of the Canadian community to deal with this situation and our successes and failures. I'll talk about how we are planning in the next decade to try to create a workable and adaptable solution to support big data science.

  16. The Canadian Astronomy Data Centre

    Science.gov (United States)

    Ball, Nicholas M.; Schade, D.; Astronomy Data Centre, Canadian

    2011-01-01

    The Canadian Astronomy Data Centre (CADC) is the world's largest astronomical data center, holding over 0.5 Petabytes of information, and serving nearly 3000 astronomers worldwide. Its current data collections include BLAST, CFHT, CGPS, FUSE, Gemini, HST, JCMT, MACHO, MOST, and numerous other archives and services. It provides extensive data archiving, curation, and processing expertise, via projects such as MegaPipe, and enables substantial day-to-day collaboration between resident astronomers and computer specialists. It is a stable, powerful, persistent, and properly supported environment for the storage and processing of large volumes of data, a condition that is now absolutely vital for their science potential to be exploited by the community. Through initiatives such as the Common Archive Observation Model (CAOM), the Canadian Virtual Observatory (CVO), and the Canadian Advanced Network for Astronomical Research (CANFAR), the CADC is at the global forefront of advancing astronomical research through improved data services. The CAOM aims to provide homogeneous data access, and hence viable interoperability between a potentially unlimited number of different data collections, at many wavelengths. It is active in the definition of numerous emerging standards within the International Virtual Observatory, and several datasets are already available. The CANFAR project is an initiative to make cloud computing for storage and data-intensive processing available to the community. It does this via a Virtual Machine environment that is equivalent to managing a local desktop. Several groups are already processing science data. CADC is also at the forefront of advanced astronomical data analysis, driven by the science requirements of astronomers both locally and further afield. The emergence of 'Astroinformatics' promises to provide not only utility items like object classifications, but to directly enable new science by accessing previously undiscovered or intractable

  17. Environmental conditions influence for real-time hologram formation on dichromated polyvinyl alcohol NiCl{sub 2}{center_dot}6H{sub 2}O doped films

    Energy Technology Data Exchange (ETDEWEB)

    Fontanilla-Urdaneta, R C; Olivares-Perez, A; Fuentes-Tapia, I; Rios-Velasco, M A, E-mail: rfontanilla@inaoep.mx, E-mail: olivares@inaoep.mx, E-mail: ifuentes@inaoep.mx, E-mail: moni_arv@hotmail.com [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Luis Enrique Erro No. 1 Tonantzintla, Puebla (Mexico)

    2011-01-01

    The real-time holographic gratings recording are studied by the presence of a metallic salt. The experimental process refers to analysis of diffraction efficiency by the influence of humidity in the coating solution on holograms formation in presence of electrical potential. The diffraction efficiency is measured as a function of the exposure energy until reach the saturation. The influence of the hologram parameters to get the diffraction efficiency is studied at room conditions.

  18. Comparative study of the catalytic activity of the complexes Cp{sup *}RuCl(PAr{sub 3}){sub 2} [Ar = -C{sub 6H}5 and 4-CF{sub 3}-C{sub 6}H{sub 4}] in the ATRP of styrene

    Energy Technology Data Exchange (ETDEWEB)

    Villa-Hernandez, Alejandro M.; Rosales-Velazquez, Claudia P.; Torres-Lubian, Jose R., E-mail: rtorres@ciqa.mx [Departamento de Sintesis de Polimeros, Centro de Investigacion en Quimica Aplicada, Coah. (Mexico); Saldivar-Guerra, Enrique [Departamento de Procesos de Polimerizacion, Centro de Investigacion en Quimica Aplicada, Coah. (Mexico)

    2011-09-15

    Styrene polymerization by ATRP was conducted independently using the complexes Cp{sup *}RuCl(PPh{sub 3}){sub 2}, and Cp{sup *}RuCl[P(4-CF{sub 3}-C{sub 6}H{sub 4}){sub 3}]{sub 2} as catalysts, in order to evaluate the influence of the electronic properties of the phosphine ligands on the rate and control of the polymerization. The kinetic data for polymerizations carried out with Cp{sup *}RuCl(PPh{sub 3}){sub 2}, show that molecular weights increase linearly with conversion with an average initiation efficiency of 0.77. The molecular weights obtained in the kinetic study with Cp{sup *}RuCl[P(4-CF{sub 3}-C{sub 6}H{sub 4}){sub 3}]{sub 2} also increase with conversion but show a marked deviation below the theoretical molecular weights. This behavior was explained by the gradual, irreversible, oxidation of catalyst Cp{sup *}RuCl[P(4-CF{sub 3}-C{sub 6}H{sub 4}){sub 3}]{sub 2} as confirmed by {sup 31}P-NMR spectroscopy. Catalyst Cp{sup *}RuCl(PPh{sub 3}){sub 2} promotes the polymerization with a rate of polymerization higher than that obtained using Cp{sup *}RuCl[P(4-CF{sub 3}-C{sub 6}H{sub 4}){sub 3}]{sub 2}; this is consistent with the better electron donating properties of PPh{sub 3} versus P(4-CF{sub 3}-C{sub 6}H{sub 4}){sub 3}. Preliminary studies of styrene polymerization by ATRP in supercritical CO{sub 2}, shows that only catalyst Cp{sup *}RuCl[P(4-CF{sub 3}-C{sub 6}H{sub 4}){sub 3}]{sub 2}, with fluorinated ligands, was active. (author)

  19. Activation of silicon quantum dots for emission

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Miao Xin-Jian; Huang Zhong-Mei; Liu Shi-Rong; Qin Chao-Jian

    2012-01-01

    The emission of silicon quantum dots is weak when their surface is passivated well. Oxygen or nitrogen on the surface of silicon quantum dots can break the passivation to form localized electronic states in the band gap to generate active centers where stronger emission occurs.From this point of view,we can build up radiative matter for emission.Emissions of various wavelengths can be obtained by controlling the surface bonds of silicon quantum dots.Our experimental results demonstrate that annealing is important in the treatment of the activation,and stimulated emissions at about 600 and 700 nm take place on active silicon quantum dots.

  20. Thermoelectric energy harvesting with quantum dots.

    Science.gov (United States)

    Sothmann, Björn; Sánchez, Rafael; Jordan, Andrew N

    2015-01-21

    We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn toward quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics.

  1. POLARON IN CYLINDRICAL AND SPHERICAL QUANTUM DOTS

    Directory of Open Access Journals (Sweden)

    L.C.Fai

    2004-01-01

    Full Text Available Polaron states in cylindrical and spherical quantum dots with parabolic confinement potentials are investigated applying the Feynman variational principle. It is observed that for both kinds of quantum dots the polaron energy and mass increase with the increase of Frohlich electron-phonon coupling constant and confinement frequency. In the case of a spherical quantum dot, the polaron energy for the strong coupling is found to be greater than that of a cylindrical quantum dot. The energy and mass are found to be monotonically increasing functions of the coupling constant and the confinement frequency.

  2. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.;

    2002-01-01

    -power surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier...... is biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...

  3. Sensitisation of visible and NIR lanthanide emission by InPZnS quantum dots in bi-luminescent hybrids.

    Science.gov (United States)

    Molloy, Jennifer K; Lincheneau, Christophe; Karimdjy, Maria Moula; Agnese, Fabio; Mattera, Lucia; Gateau, Christelle; Reiss, Peter; Imbert, Daniel; Mazzanti, Marinella

    2016-03-25

    The synthesis of stable hybrid nanoparticles combining InPZnS@ZnSe/ZnS quantum dots (QDs) and grafted lanthanide complexes has been performed using two different approaches in organic and aqueous media. The final bi-luminescent hybrids exhibit Ln(III) (Ln = Eu and Yb) centred luminescence upon QD excitation, suggesting that an energy transfer occurs from the QD to the lanthanide. PMID:26941180

  4. Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging

    OpenAIRE

    Veeranarayanan S; Poulose AC; Mohamed MS; Nagaoka Y; Iwai S.; Nakagame Y; Kashiwada S; Yoshida Y; Maekawa T; Kumar DS

    2012-01-01

    Srivani Veeranarayanan, Aby Cheruvathoor Poulose, M Sheikh Mohamed, Yutaka Nagaoka, Seiki Iwai, Yuya Nakagame, Shosaku Kashiwada, Yasuhiko Yoshida, Toru Maekawa, D Sakthi KumarBio Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, JapanAbstract: This paper presents the synthesis of aqueous cadmium sulfide (CdS) quantum dots (QDs) and silica-encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio-optical probe...

  5. Comparison of the reactivity of 2-Li-C6H4CH2NMe2 with MCl4 (M=Th, U): isolation of a thorium aryl complex or a uranium benzyne complex.

    Science.gov (United States)

    Seaman, Lani A; Pedrick, Elizabeth A; Tsuchiya, Takashi; Wu, Guang; Jakubikova, Elena; Hayton, Trevor W

    2013-09-27

    Why do U react like that? Reaction of 2-Li-C6H4CH2NMe2 with [MCl4(DME)n] (M=Th, n=2; M=U, n=0) results in the formation of a thorium aryl complex, [Th(2-C6H4CH2NMe2)4] or a uranium benzyne complex, [Li][U(2,3-C6H3CH2NMe2)(2-C6H4CH2NMe2)3]. A DFT analysis suggests that the formation of a benzyne complex with U but not with Th is a kinetic and not thermodynamic effect.

  6. From micro- to nanomagnetic dots: evolution of the eigenmode spectrum on reducing the lateral size

    Science.gov (United States)

    Carlotti, G.; Gubbiotti, G.; Madami, M.; Tacchi, S.; Hartmann, F.; Emmerling, M.; Kamp, M.; Worschech, L.

    2014-07-01

    Brillouin light scattering experiments and micromagnetic simulations have been exploited to investigate the spectrum of thermally excited magnetic eigenmodes in 10 nm-thick elliptical Permalloy dots, when the longer axis D is scaled down from about 1000 to 100 nm. It is shown that for D larger than about 200 nm the characteristics of the spin-wave eigenmodes are dominated by dipolar energy, while for D in the range of about 100 to 200 nm exchange energy effects cause qualitative and quantitative differences in the spin-wave spectrum. In this ‘mesoscopic’ regime, the usual classification scheme, involving one fundamental mode with large average magnetization and many other modes collected in families with specific symmetries, no longer holds. Rather, one finds the simultaneous presence of two modes with ‘fundamental’ character, i.e. with a significant and comparable value of the average dynamical magnetization: the former is at larger frequency and has its maximum amplitude at the dot's centre, while the latter occurs at lower frequency and is localized at the dot's edges. Interestingly, the maximum intensity swaps from the higher frequency mode to the lower frequency one, just when the dot size is reduced from about 200 to 100 nm. This is relevant in view of the exploitation of nanodots for the design of nanomagnetic devices with lateral dimensions in the above interval, such as memory cells, logic gates, reading heads and spin-torque oscillators.

  7. Review of CERN Data Centre Infrastructure

    CERN Document Server

    Andrade, P; van Eldik, J; McCance, G; Panzer-Steindel, B; Coelho dos Santos, M; Traylen, S; Schwickerath, U

    2012-01-01

    The CERN Data Centre is reviewing strategies for optimizing the use of the existing infrastructure and expanding to a new data centre by studying how other large sites are being operated. Over the past six months, CERN has been investigating modern and widely-used tools and procedures used for virtualisation, clouds and fabric management in order to reduce operational effort, increase agility and support unattended remote data centres. This paper gives the details on the project’s motivations, current status and areas for future investigation.

  8. Review of CERN Data Centre Infrastructure

    Science.gov (United States)

    Andrade, P.; Bell, T.; van Eldik, J.; McCance, G.; Panzer-Steindel, B.; Coelho dos Santos, M.; Traylen and, S.; Schwickerath, U.

    2012-12-01

    The CERN Data Centre is reviewing strategies for optimizing the use of the existing infrastructure and expanding to a new data centre by studying how other large sites are being operated. Over the past six months, CERN has been investigating modern and widely-used tools and procedures used for virtualisation, clouds and fabric management in order to reduce operational effort, increase agility and support unattended remote data centres. This paper gives the details on the project's motivations, current status and areas for future investigation.

  9. Quantum Dot Spectrum Converters for Enhanced High Efficiency Photovoltaics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This research proposes to enhance solar cell efficiency, radiation resistance and affordability. The Quantum Dot Spectrum Converter (QDSC) disperses quantum dots...

  10. Towards Human-Centred Design

    Science.gov (United States)

    Bannon, Liam J.

    The field of HCI has evolved and expanded dramatically since its origin in the early 1980’s. The HCI community embraces a large community of researchers and practitioners around the world, from a variety of disciplinary backgrounds in the human and social sciences, engineering and informatics, and more recently, the arts and design disciplines. This kaleidoscope of cultures and disciplines as seen at INTERACT Conferences provides a rich pool of resources for examining our field. Applications are increasingly exploring our full range of sensory modalities, and merging the digital and physical worlds. WiFi has opened up a huge design space for mobile applications. A focus on usability of products and services has been complemented by an emphasis on engagement, enjoyment and experience. With the advent of ubiquitous computing, and the emergence of “The Internet of Things”, new kinds of more open infrastructures make possible radically new kinds of applications. The sources of innovation have also broadened, to include human and social actors outside of the computing and design organizations. The question is to what extent is our mainstream thinking in the HCI field ready for the challenges of this Brave New World? Do the technological and social innovations that we see emerging require us to re-shape, or even, re-create, our field, or is it a case of a more gradual evolution and development of that which we already know? In this closing Keynote, I will provide a perspective on the evolution and development of the HCI field, looking backwards as well as forwards, in order to determine what are some of the changes of significance in the field. This “broad-brush” approach to what I term “ human-centred design” will be complemented by the examination of specific projects and applications, to help anchor some of the discussion. Areas such as user-centred design, participatory design, computer-supported cooperative work and learning, and interaction design, in

  11. Photophysical Properties and Photoinduced Electron Transfer between [60]Fullerene-Containing Cyclic Sulphoxide [ C60-C6H8SO] and Tetrathiafulvalene (TTF) by Laser Flash Photolysis

    Institute of Scientific and Technical Information of China (English)

    ZENG,He-Ping(曾和平)

    2002-01-01

    Photoinduced electron transfer (PET) processes between C60-C6H8SO and Tetrathiafulvalene (TTF) have been studied by nanosecond laser photolysis. Quantum yields (φet) and rate constants of electron transfer (ket) from TTF to excited triplet state of [ 60 ] fullerene-containing cyclic sulphoxide in benzonitrile (BN) have been evaluated by observing the transient absorption bands in the NIR region. With the decay of excited triplet state of [ 60 ] fullerene-containing cyclic sulphoxide, the rise of radical anion of [60]fullerene-containing cyclic sulphoxide is observed.

  12. Synthesis, Structure and Characterization of Two-dimensional Network Copper Complex [ Cu3 (nta) 2(azpy) 2(H2O)2]· 6H2O

    Institute of Scientific and Technical Information of China (English)

    LI,Bao-Long(李宝龙); XU,Yan(徐艳); LIU,Qi(刘琦); WANG,Hua-Qin(王化勤); XU,Zheng(徐正)

    2002-01-01

    The copper(Ⅱ) complex [Cu3(nta)2(azpy)2(H2O)2] @6H2O(nta= nitrilotriacetate, azpy= 4,4'-azobispyridine) has been synthesized and characterized. The X-ray analysis reveals that there are two kinds of copper(Ⅱ) coordination environments.Cu(1) has a distorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1)is linked to Cu(2)through nta and bound to Cu(1C) by azpy, and Cu(2) islinked to Cu(2A) through azpy, which extends to two-dimensional network with large rhombus 1.2 nm× 1.7 nm.

  13. Comparison of the formation process and properties of epitaxial graphenes on Si-and C-face 6H-SiC substrates

    Institute of Scientific and Technical Information of China (English)

    Wang Dang-Chao; Zhang Yu-Ming; Zhang Yi-Men; Lei Tian-Min; Guo Hui; Wang Yue-Hu; Tang Xiao-Yan; Wang Hang

    2012-01-01

    In this paper,the epitaxial graphene layers grown on Si- and C-face 6H-SiC substrates are investigated under a low pressure of 400 Pa at 1600 ℃.By using atomic force microscopy and Raman spectroscopy,we find that there are distinct differences in the formation and the properties between the epitaxial graphene layers grown on the Si-face and the C-face substrates,including the hydrogen etching process,the stacking type,and the number of layers.Hopefully,our results will be useful for improving the quality of the epitaxial graphene on SiC substrate.

  14. Experimental demonstration of mode-selective phonon excitation of 6H-SiC by a mid-infrared laser with anti-Stokes Raman scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Kyohei; Hachiya, Kan; Okumura, Kensuke; Mishima, Kenta; Inukai, Motoharu; Torgasin, Konstantin; Omer, Mohamed [Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Sonobe, Taro [Kyoto University Research Administration Office, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Zen, Heishun; Negm, Hani; Kii, Toshiteru; Masuda, Kai; Ohgaki, Hideaki [Institute of Advanced Energy, Kyoto University, Gokasyo, Uji, Kyoto 611-0011 (Japan)

    2013-10-28

    Mode-selective phonon excitation by a mid-infrared laser (MIR-FEL) is demonstrated via anti-Stokes Raman scattering measurements of 6H-silicon carbide (SiC). Irradiation of SiC with MIR-FEL and a Nd-YAG laser at 14 K produced a peak where the Raman shift corresponds to a photon energy of 119 meV (10.4 μm). This phenomenon is induced by mode-selective phonon excitation through the irradiation of MIR-FEL, whose photon energy corresponds to the photon-absorption of a particular phonon mode.

  15. Vapor-Liquid Equilibrium in the Mixture 1-Chlorobutane C4H9Cl + C6H10O Cyclohexanone (EVLM1111, LB5637_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1-Chlorobutane C4H9Cl + C6H10O Cyclohexanone (EVLM1111, LB5637_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  16. Heat of Mixing and Solution of 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (HMSD1111, LB3663_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (HMSD1111, LB3663_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  17. Heat of Mixing and Solution of 1,1,2-Trichloroethane C2H3Cl3 + C6H10O Cyclohexanone (HMSD1111, LB3665_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of 1,1,2-Trichloroethane C2H3Cl3 + C6H10O Cyclohexanone (HMSD1111, LB3665_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  18. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8O Methyl phenyl ether (VMSD1111, LB4823_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8O Methyl phenyl ether (VMSD1111, LB4823_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  19. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8 Toluene (VMSD1212, LB4826_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8 Toluene (VMSD1212, LB4826_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  20. Volumetric Properties of the Mixture Oxolane C4H8O + C6H10O Cyclohexanone (VMSD1212, LB3919_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Oxolane C4H8O + C6H10O Cyclohexanone (VMSD1212, LB3919_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  1. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8O Methyl phenyl ether (VMSD1511, LB4833_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8O Methyl phenyl ether (VMSD1511, LB4833_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  2. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C9H12 1,3,5-Trimethylbenzene (VMSD1111, LB4822_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C9H12 1,3,5-Trimethylbenzene (VMSD1111, LB4822_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  3. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C8H10 1,4-Dimethylbenzene (VMSD1511, LB4830_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C8H10 1,4-Dimethylbenzene (VMSD1511, LB4830_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  4. Volumetric Properties of the Mixture Ethane-1,2-diol C2H6O2 + C6H10O Cyclohexanone (VMSD1212, LB4988_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethane-1,2-diol C2H6O2 + C6H10O Cyclohexanone (VMSD1212, LB4988_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  5. Vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (EVLM1111, LB5653_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (EVLM1111, LB5653_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  6. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8 Toluene (VMSD1511, LB4831_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8 Toluene (VMSD1511, LB4831_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  7. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C8H10 1,4-Dimethylbenzene (VMSD1212, LB4825_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C8H10 1,4-Dimethylbenzene (VMSD1212, LB4825_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  8. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8O Methyl phenyl ether (VMSD1212, LB4828_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8O Methyl phenyl ether (VMSD1212, LB4828_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  9. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C9H12 1,3,5-Trimethylbenzene (VMSD1212, LB4827_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C9H12 1,3,5-Trimethylbenzene (VMSD1212, LB4827_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  10. Volumetric Properties of the Mixture Ethane-1,2-diol C2H6O2 + C6H10O Cyclohexanone (VMSD1111, LB4980_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethane-1,2-diol C2H6O2 + C6H10O Cyclohexanone (VMSD1111, LB4980_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  11. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8 Toluene (VMSD1111, LB4820_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H8 Toluene (VMSD1111, LB4820_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  12. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C9H12 1,3,5-Trimethylbenzene (VMSD1511, LB4832_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C9H12 1,3,5-Trimethylbenzene (VMSD1511, LB4832_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  13. Volumetric Properties of the Mixture Oxolane C4H8O + C6H10O Cyclohexanone (VMSD1111, LB3912_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Oxolane C4H8O + C6H10O Cyclohexanone (VMSD1111, LB3912_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  14. Heat of Mixing and Solution of Pentachloroethane C2HCl5 + C6H10O Cyclohexanone (HMSD1111, LB3667_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of Pentachloroethane C2HCl5 + C6H10O Cyclohexanone (HMSD1111, LB3667_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  15. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H14 Methylcyclohexane (VMSD1112, LB3138_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H14 Methylcyclohexane (VMSD1112, LB3138_V)' providing data by calculation of mass density in the single-phase region(s) from low-pressure dilatometric measurements of the molar excess volume at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H14 Methylcyclohexane (VMSD1211, LB3134_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C7H14 Methylcyclohexane (VMSD1211, LB3134_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  17. Volumetric Properties of the Mixture Cyclohexanone C6H10O + C8H10 1,4-Dimethylbenzene (VMSD1111, LB4821_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexanone C6H10O + C8H10 1,4-Dimethylbenzene (VMSD1111, LB4821_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  18. Heat of Mixing and Solution of 1,1,1-Trichloroethane C2H3Cl3 + C6H10O Cyclohexanone (HMSD1111, LB3664_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of 1,1,1-Trichloroethane C2H3Cl3 + C6H10O Cyclohexanone (HMSD1111, LB3664_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  19. Theoretical analysis and design of double implanted MOSFET on 6H silicon carbide wafer for low power dissipation and large breakdown voltage

    Directory of Open Access Journals (Sweden)

    Munish Vashishath

    2008-05-01

    Full Text Available This paper analyses the device structure of a 6H-SiC vertical double-implanted MOSFET (DIMOSFET in order to provide a high breakdown voltage of about 10 kV and a low power dissipation for a rise in device temperature of 600 oC. Analysis of an 800 W power dissipation for stable device operation corresponding to this temperature rise shows optimum doping levels of the drift region lying between 5*1013 cm-3 and 5*1015 cm-3 for a breakdown voltage of 10 kV.

  20. Quantum Gates Between Two Spins in a Triple Dot System with an Empty Dot

    CERN Document Server

    Coello, Jose Garcia

    2011-01-01

    We propose a scheme for implementing quantum gates and entanglement between spin qubits in the outer dots of a triple-dot system with an empty central dot. The voltage applied to the central dot can be tuned to realize the gate. Our scheme exemplifies the possibility of quantum gates outside the regime where each dot has an electron, so that spin-spin exchange interaction is not the only relevant mechanism. Analytic treatment is possible by mapping the problem to a t-J model. The fidelity of the entangling quantum gate between the spins is analyzed in the presence of decoherence stemming from a bath of nuclear spins, as well as from charge fluctuations. Our scheme provides an avenue for extending the scope of two qubit gate experiments to triple-dots, while requiring minimal control, namely that of the potential of a single dot, and may enhance the qubit separation to ease differential addressability.

  1. Nitrogen-Doped Carbon Dots for "green" Quantum Dot Solar Cells.

    Science.gov (United States)

    Wang, Hao; Sun, Pengfei; Cong, Shan; Wu, Jiang; Gao, Lijun; Wang, Yun; Dai, Xiao; Yi, Qinghua; Zou, Guifu

    2016-12-01

    Considering the environment protection, "green" materials are increasingly explored for photovoltaics. Here, we developed a kind of quantum dots solar cell based on nitrogen-doped carbon dots. The nitrogen-doped carbon dots were prepared by direct pyrolysis of citric acid and ammonia. The nitrogen-doped carbon dots' excitonic absorption depends on the N-doping content in the carbon dots. The N-doping can be readily modified by the mass ratio of reactants. The constructed "green" nitrogen-doped carbon dots solar cell achieves the best power conversion efficiency of 0.79 % under AM 1.5 G one full sun illumination, which is the highest efficiency for carbon dot-based solar cells. PMID:26781285

  2. Symmetric centres of braided monoidal categories

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper introduces the concept of‘symmetric centres' of braided monoidal categories. Let H be a Hopf algebra with bijective antipode over a field k. We address the symmetric centre of the Yetter-Drinfel'd module category HH(yD) and show that a left Yetter-Drinfel'd module M belongs to the symmetric centre of HH(yD) if and only if M is trivial. We also study the symmetric centres of categories of representations of quasitriangular Hopf algebras and give a sufficient and necessary condition for the braid of H(M) to induce the braid of (H(H)(A),(○)A,A,φ,l,r), or equivalently, the braid of (A#H(H),(○)A,A,φ,l,r), where A is a quantum commutative H-module algebra.

  3. Photoinduced electron transfers with carbon dots

    OpenAIRE

    Wang, Xin; Cao, Li; Lu, Fushen; Meziani, Mohammed J.; Li, Heting; Qi, Gang; Zhou, Bing; Harruff, Barbara A.; Kermarrec, Fabien; Sun, Ya-Ping

    2009-01-01

    The photoluminescence in carbon dots (surface-passivated small carbon nanoparticles) could be quenched efficiently by electron acceptor or donor molecules in solution, namely that photo-excited carbon dots are both excellent electron donors and excellent electron acceptors, thus offering new opportunities for their potential uses in light energy conversion and related applications.

  4. Thick-shell nanocrystal quantum dots

    Science.gov (United States)

    Hollingsworth, Jennifer A.; Chen, Yongfen; Klimov, Victor I.; Htoon, Han; Vela, Javier

    2011-05-03

    Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

  5. Optical Properties of Semiconductor Quantum Dots

    NARCIS (Netherlands)

    Perinetti, U.

    2011-01-01

    This thesis presents different optical experiments performed on semiconductor quantum dots. These structures allow to confine a small number of electrons and holes to a tiny region of space, some nm across. The aim of this work was to study the basic properties of different types of quantum dots mad

  6. Detecting the chirality for coupled quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Cao Huijuan [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China); Hu Lian [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)], E-mail: huliancaohj@yahoo.com

    2008-04-21

    We propose a scheme to detect the chirality for a system consisting of three coupled quantum dots. The chirality is found to be determined by the frequency of the transition between chiral states under the chiral symmetry broken perturbation. The results are important to construct quantum gates and to demonstrate chiral entangle states in the triangle spin dots.

  7. Double Acceptor Interaction in Semimagnetic Quantum Dot

    Directory of Open Access Journals (Sweden)

    A. Merwyn Jasper D. Reuben

    2011-01-01

    Full Text Available The effect of geometry of the semimagnetic Quantum Dot on the Interaction energy of a double acceptor is computed in the effective mass approximation using the variational principle. A peak is observed at the lower dot sizes as a magnetic field is increased which is attributed to the reduction in confinement.

  8. The relativistic two-centre continuum

    International Nuclear Information System (INIS)

    A method is presented to define unique continuum states for the two-centre Dirac Hamiltonian. In the spherical limit these states become the familiar angular momentum eigenstates of the radial Coulomb potential. The different states for a fixed total energy vertical strokeEvertical stroke > m may be distinguished by considering the asymptotic spin-angular distribution of states with unique scattering-phases. First numerical solutions of the two-centre Dirac equation for continuum states are presented. (orig.)

  9. INFOTERM – Information Disseminating Centre for Terminology

    OpenAIRE

    Albina Auksoriūtė

    2014-01-01

    International Information Centre for Terminology (INFOTERM) was founded in 1971 by contract with the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the Austrian Standards Institute (ASI). In 1996, INFOTERM was reorganized and established as an independent non-profit organization. INFOTERM promotes and supports the cooperation of existing and the establishment of new terminology centres and networks with the general aim to improve domain communication, knowledge ...

  10. Two centre problems in relativistic atomic physics

    OpenAIRE

    McConnell, Sean R.

    2012-01-01

    The work contained within this thesis is concerned with the explanation and usage of a set of theoretical procedures for the study of static and dynamic two–centre problems in the relativistic framework of Dirac’s equation. Two distinctly different theories for handling time–dependent atomic interactions are reviewed, namely semi–classical perturbation theory and a non–perturbative numerical technique based on the coupled channel equation to directly solve the time–dependent, two–centre Dirac...

  11. Joint Research Centre. Ispra establishment-Italy

    International Nuclear Information System (INIS)

    A comprehensive review of the work carried out during 1974 and 1975 in the Ispra establishment of the Joint Research Centre is presented. A description of the activity carried out within the context of the running programmes is given. Some of the most relevant scientific and technical achievement are described from the viewpoints of the Scientific Departments of the Centre. The technical and administrative support activities are also presented. A list of publications issued by the Ispra Scientific staff is given

  12. Social innovation for People-Centred Development

    DEFF Research Database (Denmark)

    Hulgård, Lars; P.K., Shajahan

    2013-01-01

    Social innovation is closely related to the people-centred development (PCD) framework of knowledge production. The discussion of PCD in this chapter particularly expands on the feature of empowerment and socio-political mobilization of people in social innovation......Social innovation is closely related to the people-centred development (PCD) framework of knowledge production. The discussion of PCD in this chapter particularly expands on the feature of empowerment and socio-political mobilization of people in social innovation...

  13. Perspectives on recycling centres and future developments.

    Science.gov (United States)

    Engkvist, I-L; Eklund, J; Krook, J; Björkman, M; Sundin, E

    2016-11-01

    The overall aim of this paper is to draw combined, all-embracing conclusions based on a long-term multidisciplinary research programme on recycling centres in Sweden, focussing on working conditions, environment and system performance. A second aim is to give recommendations for their development of new and existing recycling centres and to discuss implications for the future design and organisation. Several opportunities for improvement of recycling centres were identified, such as design, layout, ease with which users could sort their waste, the work environment, conflicting needs and goals within the industry, and industrialisation. Combining all results from the research, which consisted of different disciplinary aspects, made it possible to analyse and elucidate their interrelations. Waste sorting quality was recognized as the most prominent improvement field in the recycling centre system. The research identified the importance of involving stakeholders with different perspectives when planning a recycling centre in order to get functionality and high performance. Practical proposals of how to plan and build recycling centres are given in a detailed checklist. PMID:26826952

  14. Medication errors: pharmacovigilance centres in detection and prevention

    OpenAIRE

    Bencheikh, Rachida Soulaymani; Benabdallah, Ghita

    2009-01-01

    Detecting medication errors needs collaboration between various organizations, such as patient safety institutions, pharmacovigilance centres, and poison control centres. In order to evaluate the input of pharmacovigilance centres and poison control centres in detecting and evaluating medication errors a pilot project was initiated by the World Alliance for Patient Safety in collaboration with the Uppsala Monitoring Centre; the Moroccan pharmacovigilance centre acted as project coordinator. A...

  15. Model-based clustered-dot screening

    Science.gov (United States)

    Kim, Sang Ho

    2006-01-01

    I propose a halftone screen design method based on a human visual system model and the characteristics of the electro-photographic (EP) printer engine. Generally, screen design methods based on human visual models produce dispersed-dot type screens while design methods considering EP printer characteristics generate clustered-dot type screens. In this paper, I propose a cost function balancing the conflicting characteristics of the human visual system and the printer. By minimizing the obtained cost function, I design a model-based clustered-dot screen using a modified direct binary search algorithm. Experimental results demonstrate the superior quality of the model-based clustered-dot screen compared to a conventional clustered-dot screen.

  16. Substitutional impurity in the graphene quantum dots

    Science.gov (United States)

    Sierański, K.; Szatkowski, J.

    2015-09-01

    The process of formation of the localized defect states due to substitutional impurity in sp2-bonded graphene quantum dot is considered using a simple tight-binding-type calculation. We took into account the interaction of the quantum dot atoms surrounding the substitutional impurity from the second row of elements. To saturate the external dangling sp2 orbitals of the carbon additionally 18 hydrogen atoms were introduced. The chemical formula of the quantum dot is H18C51X, where X is the symbol of substitutional atom. The position of the localized levels is determined relative to the host-atoms (C) εp energies. We focused on the effect of substitutional doping by the B, N and O on the eigenstate energies and on the total energy change of the graphene dots including for O the effect of lattice distorsion. We conclude that B, N, and O can form stable substitutional defects in graphene quantum dot.

  17. Synthesis and Structure of Dinuclear Molybdenum Carbonyl Thiolate Compound[Et4N]2[Mo2(CO)8(SC6H4-CH3-p)2

    Institute of Scientific and Technical Information of China (English)

    潘国华; 庄伯涛; 魏强; 黄梁仁

    2000-01-01

    Reaction of Mo(CO)6 with p-CH3-C6H4SNa and Et4NCl· H2O in CH3 CN afforded a dinuclear molybdenum (0) compound [ Et4 N ] 2 [ Mo2 (CO) 8 ( SC6 H4 -CH3-p)2 ] (1). The crystal structure of 1. 2 MeCN was determined by X-ray diffraction. The crystallographic data: C42H60Mo2N4O8S2, Mr = 1005.07, triclinic, P 1,a=9.694(3), b=9.999(3), c=13.012(2)(A。), a=99.72(2), β=97.01(1), γ=97.36(3)°, V=1219.5(1)(A。)3, Z=1, Dc=1.40g/cm3, F(000)=532, μ=6.3cm-1 , Final R =0.038 and Rw =0.046 for 4097 reflections with I>3.0σ(I). The Xray structure analysis revealed that the Mo2 S2 core is planar. The geometry around each Mo atom is a distorted octahedron, both of which form an edge-sharing bioctahedron.The Mo…Mo distance is 4.0342(5)(A。),which obviously indicates the absence of Mo-Mo bond.

  18. Direct growth of hexagonal InN films on 6H-SiC by radio-frequency metal-organic molecular-beam epitaxy

    International Nuclear Information System (INIS)

    Wurtzite InN films were prepared on a 6H-SiC substrate by a self-designed plasma-assisted metal-organic molecular-beam epitaxy system without a buffer layer. In this article, the authors investigate the structural and optical properties of InN films grown on a 6H-SiC substrate. The crystallinity and microstructure of the thin film were further characterized by x-ray diffraction (XRD), field-emission scanning-electron microscopy, and transmission-electron microscopy. Electrical and optical properties were evaluated by Hall and photoluminescence (PL) measurements. XRD results indicate that InN film grown at 500 deg. C is epitaxially grown along the c-axis orientation. The two-dimensional growth mode is clearly shown in scanning-electron microscope images. Room-temperature PL spectra show that the emission peak is located at ∼0.83 eV due to the Burstein-Moss effect. In addition, the crystalline InN samples crack and peel away from the substrate at elevated growth temperature. This phenomenon may be attributed to lattice mismatch and grain coalescence while increasing the growth temperature. The narrow window of the growth temperature plays an important role in engineering the InN epitaxial growth.

  19. A quantum-classical simulation of a multi-surface multi-mode nuclear dynamics on C6H$^{+}_{6}$ incorporating degeneracy among electronic states

    Indian Academy of Sciences (India)

    Subhankar Sardar; Satrajit Adhikari

    2012-01-01

    We have performed a nuclear dynamics simulation to calculate photoelectron spectra and population profiles of benzene radical cation (C6H$^{+}_{6}$) employing the parallelized Time Dependent Discrete Variable Representation (TDDVR) approach. For this purpose, we have considered two multi-state multi-mode model Hamiltonians of C6H$^{+}_{6}$ with degeneracy among the electronic states: (a) One consists of three states and eight modes, which in turn leads to a five state thirteen mode Hamiltonian (2E1-2E2-2A2) due to the degeneracy; and (b) The other is constituted of three states and thirteen modes which is basically a five state twenty mode Hamiltonian (2E2-2E1-2B2) for the same reason. Since these electronic states are interconnected by several conical intersections in the vicinity of the Franck Condon region, it will be challenging to pursue such large dynamical calculation in the presence of nonadiabaticity among the electronic states. The spectral as well as population profiles calculated with the advent of TDDVR approach show reasonably good agreement with the results obtained by the Multi Configuration Time Dependent Hartree (MCTDH) methodology.

  20. 6H-Indolo[2,3-b]quinoxaline-based organic dyes containing different electron-rich conjugated linkers for highly efficient dye-sensitized solar cells

    Science.gov (United States)

    Qian, Xing; Gao, Huan-Huan; Zhu, Yi-Zhou; Lu, Lin; Zheng, Jian-Yu

    2015-04-01

    A new class of organic dyes based on 6H-indolo[2,3-b]quinoxaline are synthesized and applied as photosensitizers for dye-sensitized solar cells. Different electron-rich π-conjugated bridges such as oligothiophene, thienyl carbazole, and furyl carbazole are introduced to cooperate with 6H-indolo[2,3-b]quinoxaline and cyanoacrylic acid anchoring group to give the dyes JY01, JY02, and JY03, respectively. Their photophysical, electrochemical, and photovoltaic properties are further investigated. All three dyes show good performances as photosensitizers. In particular, DSSC based on JY01 shows the best photovoltaic performance with a short-circuit photocurrent density of 16.0 mA cm-2, an open-circuit photovoltage of 708 mV and a fill factor of 0.67, corresponding to an overall power conversion efficiency of 7.62% under AM 1.5 irradiation (100 mW cm-2).

  1. Synthesis of a new intercalating nucleic acid 6H-INDOLO[2,3-b] quinoxaline oligonucleotides to improve thermal stability of Hoogsteen-type triplexes.

    Science.gov (United States)

    Osman, Amany M A; Pedersen, Erik B; Bergman, Jan

    2013-01-01

    A new intercalating nucleic acid monomer X was obtained in high yield starting from alkylation of 4-iodophenol with (S)-(+)-2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanol under Mitsunobu conditions followed by hydrolysis with 80% aqueous acetic acid to give a diol which was coupled under Sonogashira conditions with trimethylsilylacetylene (TMSA) to achieve the TMS protected (S)-4-(4-((trimethylsilyl)ethynyl)phenoxy)butane-1,2-diol. Tetrabutylammonium flouride was used to remove the silyl protecting group to obtain (S)-4-(4-ethynylphenoxy)butane-1,2-diol which was coupled under Sonogashira conditions with 2-(9-bromo-6H-indolo[2,3-b]quinoxalin-6-yl)-N,N-dimethylethanamine to achieve (S)-4-(4-((6-(2-(dimethylamino)ethyl)-6H-indolo[2,3-b]quinoxalin-9-yl)ethynyl)phenoxy)butane-1,2-diol. This compound was tritylated with 4,4'-dimethoxytrityl chloride followed by treatment with 2-cyanoethyltetraisopropylphosphordiamidite in the presence of N,N'-diisopropyl ammonium tetrazolide to afford the corresponding phosphoramidite. This phosphoramidite was used to insert the monomer X into an oligonucleotide which was used for thermal denaturation studies of a corresponding parallel triplex.

  2. Crystal structure of a new organic condensed phosphate (C6H9N3O)H2P2O7

    International Nuclear Information System (INIS)

    Crystals of a new organic compound, the isonicotinic acid hydrazide dihydrogendiphosphate (C6H9N3O)H2P2O7 (denoted INHDP) were prepared and grown at room temperature. The INHDP crystallizes in the triclinic system with the P1-bar space group. Its unit cell dimensions are: a=7.316(3)A, b=7.783(3)A, c=10.802(4)A, α=82.41(3)o, β=75.19(3)o, γ=72.57(3)o, with V=566.3(4)A3 and Z=2. Crystal structure has been determined and refined to a reliability R factor of 0.0389. The atomic arrangement can be described as inorganic infinite ribbons of H2P2O72- anions spreading parallel to the b-axis. These ribbons are themselves interconnected by the organic (C6H9N3O)+ cations so as to build a three dimensional arrangement. In the present work, we describe the crystal structure, thermal behaviour and IR analysis of this new compound

  3. Characterization of the ion-amorphization process and thermal annealing effects on third generation SiC fibers and 6H-SiC

    Directory of Open Access Journals (Sweden)

    Huguet-Garcia Juan

    2015-01-01

    Full Text Available The objective of the present work is to study the irradiation effects on third generation SiC fibers which fulfill the minimum requisites for nuclear applications, i.e. Hi-Nicalon type S, hereafter HNS, and Tyranno SA3, hereafter TSA3. With this purpose, these fibers have been ion-irradiated with 4 MeV Au ions at room temperature and increasing fluences. Irradiation effects have been characterized in terms of micro-Raman Spectroscopy and Transmission Electron Microscopy and compared to the response of the as-irradiated model material, i.e. 6H-SiC single crystals. It is reported that ion-irradiation induces amorphization in SiC fibers. Ion-amorphization kinetics between these fibers and 6H-SiC single crystals are similar despite their different microstructures and polytypes with a critical amorphization dose of ∼3 × 1014 cm−2 (∼0.6 dpa at room temperature. Also, thermally annealing-induced cracking is studied via in situ Environmental Scanning Electron Microscopy. The temperatures at which the first cracks appear as well as the crack density growth rate increase with increasing heating rates. The activation energy of the cracking process yields 1.05 eV in agreement with recrystallization activation energies of ion-amorphized samples.

  4. Synthesis and Structural Characterization of Pd[CH3O(O)C6H3CHNNC(S)NH2](C5H5N)

    Institute of Scientific and Technical Information of China (English)

    訾凤兰; 周荫庄; 鲁晓明; 刘顺成; 金祥林

    2003-01-01

    The reaction of palladium chloride with isovanillin semithiocarbazone (VSTC),CH3O(OH)C6H3CH=NNC(S)NH2, in a mixed solvent of ethanol, pyridine and water yielded the mononuclear palladium(Ⅱ) complex Pd[CH3O(O)C6H3CHNNC(S)NH2](C5H5N), and its singlecrystal structure was determined by X-ray diffraction. The crystal belongs to triclinic, space group P1-with a = 7.715(4), b = 9.809(6), c = 10.612(4) , α = 93.54(4), β = 111.00(3), γ= 95.92(5)°, V =745.0(7) A3, Mr= 408.75, Z = 2, Dc= 1.822 g/em3, t= 1.397 mm-1, and F(000) = 408. The final R =0.0568 and wR = 0.1439 for 2616 observed independent reflections with Ⅰ> 2.0σ(Ⅰ). It was revealed that the palladium atom is bound to a tridentate donor ligand and a pyfidine in a planar square arrangement. The sulphur-nitrogen-oxygen donor of the Schiff-base ligand in the thiol form rather than the thione one is coordinated to the palladium atom via the mercapto sulphur, the β-nitrogen and the hydroxylate oxygen atoms.

  5. Electron transport in quantum dots

    CERN Document Server

    2003-01-01

    When I was contacted by Kluwer Academic Publishers in the Fall of 200 I, inviting me to edit a volume of papers on the issue of electron transport in quantum dots, I was excited by what I saw as an ideal opportunity to provide an overview of a field of research that has made significant contributions in recent years, both to our understanding of fundamental physics, and to the development of novel nanoelectronic technologies. The need for such a volume seemed to be made more pressing by the fact that few comprehensive reviews of this topic have appeared in the literature, in spite of the vast activity in this area over the course of the last decade or so. With this motivation, I set out to try to compile a volume that would fairly reflect the wide range of opinions that has emerged in the study of electron transport in quantum dots. Indeed, there has been no effort on my part to ensure any consistency between the different chapters, since I would prefer that this volume instead serve as a useful forum for the...

  6. Transmission of HIV in dialysis centre.

    Science.gov (United States)

    Velandia, M; Fridkin, S K; Cárdenas, V; Boshell, J; Ramirez, G; Bland, L; Iglesias, A; Jarvis, W

    1995-06-01

    In August, 1993, 13 dialysis patients at one dialysis centre in Colombia, South America, were found to be HIV positive, and this prompted an epidemiological investigation. We carried out a cohort study of all dialysis centre patients during January, 1992 to December, 1993 (epidemic period) to determine risk factors for HIV seroconversion. Haemodialysis and medical records were reviewed, dialysis centre staff and surviving patients were interviewed, and dialysis practices were observed. Stored sera from all dialysis centre patients were tested for HIV antibody. 12 (52%) of 23 patients tested positive for HIV antibody by enzyme immunoassay and western blot during the epidemic period. Of the 23 tested, 9 (39%) converted from HIV antibody negative to positive (seroconverters) and 10 (44%) remained HIV negative (seronegatives). The HIV seroconversion rate was higher among patients dialysed at the centre while a new patient, who was HIV seropositive, was dialysed there (90% vs 0%; p dialysis centre reprocessed access needles, dialysers, and bloodlines (60% vs 0%). While 2 of 9 HIV seroconverters had had sex with prostitutes, none had received unscreened blood products or had other HIV risk factors. No surgical or dental procedures were associated with HIV seroconversion. Dialysers were reprocessed separately with 5% formaldehyde and were labelled for use on the same patient. Access needles were reprocessed by soaking them in a common container with a low-level disinfectant, benzalkonium chloride; 4 pairs of needles were placed in one pan creating the potential for cross-contamination or use of one patient's needles on another patient. HIV transmission at the dialysis centre was confirmed. Improperly reprocessed patient-care equipment, most probably access needles, is the likely mechanism of transmission. This outbreak was discovered by accident and similar transmission may be occurring in many other countries where low-level disinfectants are used to sterilise critical

  7. Properties of point defects either native or induced by irradiation in the 3C and 6H polytypes of silicon carbide determined by positron annihilation and EPR; Proprietes des defauts ponctuels natifs et induits par irradiation dans les polytypes 3C et 6H du carbure de silicium determinees par annihilation de positons et RPE

    Energy Technology Data Exchange (ETDEWEB)

    Kerbiriou, X

    2006-02-15

    Potential applications of silicon carbide (SiC) in micro-electronics have justified many studies on point defects, which play an important role in the electrical compensation. Moreover, this material has many assets to take part in the fissile materials confining in the gas cooled reactors of the future (4. generation). In this thesis, we have used Electronic Paramagnetic Resonance and Positron Annihilation Spectroscopy to study the properties of point defects (nature, size, charge state, migration and agglomeration during annealing), either native or induced by irradiation with various particles (H{sup +}, e{sup -}, carbon ions), in the 3C and 6H polytypes of SiC. The positron annihilation study of native defects in 6H-SiC has shown the presence of a strong concentration of non-vacancy traps of acceptor type, which are not present in the 3C-SiC crystals. The nature of the defects detected after irradiation with low energy electrons (190 keV) depends on the polytype. Indeed, while silicon Frenkel pairs and carbon mono-vacancies are detected in the 6H crystals, only carbon mono-vacancies are detected in the 3C crystals. We propose that these differences concerning the populations of detected point defects result from different values of the silicon displacement threshold energy for the two polytypes (approximately 20 eV for 6H and 25 V for 3C). In addition, the irradiations with 12 MeV protons and 132 MeV carbon ions have created silicon mono-vacancies as well as VSi-VC di-vacancies. Neither the particle (protons or ions carbon), nor the polytype (3C or 6H) influence the nature of the generated defects. Finally the study of the annealing of 6H-SiC monocrystals irradiated with 12 MeV protons have revealed several successive processes. The most original result is the agglomeration of the silicon mono-vacancies with the VSi-VC di-vacancies which leads to the formation of VSi-VC-VSi tri-vacancies. (author)

  8. Scavenger hunt in the CERN Computing Centre

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Hidden among the racks of servers and disks in the CERN Computing Centre, you’ll find Hawaiian dancers, space aliens, gorillas… all LEGO® figurines! These characters were placed about the Centre for the arrival of Google’s Street View team for the world to discover.   PLEASE NOTE THAT THE COMPETITION IS OVER. ONLY FOR REFERENCE, HERE IS THE ORIGINAL ARTICLE. We’re pleased to announce our first global scavenger hunt! Spot three LEGO® figurines using Google’s Street View and you’ll be entered to win a gift of your choice from our CERN Gift Guide. A LEGO® figurine in the CERN Computing Centre, as seen on Google Street View. Here are the details: Find at least three LEGO® figurines hidden around the CERN Computing Centre using Google Street View.   Take screencaps of the figurines and e-mail the pictures to TreasureHunt-ComputingCentre@cern.ch. This email is no longer active.   The...

  9. Visits to Tier-1 Computing Centres

    CERN Multimedia

    Dario Barberis

    At the beginning of 2007 it became clear that an enhanced level of communication is needed between the ATLAS computing organisation and the Tier-1 centres. Most usual meetings are ATLAS-centric and cannot address the issues of each Tier-1; therefore we decided to organise a series of visits to the Tier-1 centres and focus on site issues. For us, ATLAS computing management, it is most useful to realize how each Tier-1 centre is organised, and its relation to the associated Tier-2s; indeed their presence at these visits is also very useful. We hope it is also useful for sites... at least, we are told so! The usual participation includes, from the ATLAS side: computing management, operations, data placement, resources, accounting and database deployment coordinators; and from the Tier-1 side: computer centre management, system managers, Grid infrastructure people, network, storage and database experts, local ATLAS liaison people and representatives of the associated Tier-2s. Visiting Tier-1 centres (1-4). ...

  10. Synthesis of 2-substituted 9-oxa-guanines {5-aminooxazolo[5,4-d]pyrimidin-7(6H-ones} and 9-oxa-2-thio-xanthines {5-mercaptooxazolo[5,4-d]pyrimidin-7(6H-ones}

    Directory of Open Access Journals (Sweden)

    2008-07-01

    Full Text Available Oxazolo[5,4-d]pyrimidines can be considered as 9-oxa-purine analogs of naturally occurring nucleic acid bases. Interest in this ring system has increased due to recent reports of biologically active derivatives. In particular, 5-aminooxazolo[5,4-d]pyrimidine-7(6H-ones (9-oxa-guanines have been shown to inhibit ricin. The preparation of a series of 2-substituted 5-aminooxazolo[5,4-d]pyrimidin-7(6H-ones and related 5-thio-oxazolo[5,4-d]pyrimidines is described, including analogs suitable for further elaboration employing “click” chemistry utilizing copper-catalyzed Huisgen 1,3-dipolar cycloadditions. Two of the compounds prepared were found to inhibit ricin with IC50 ca. 1–3 mM.

  11. Synthesis and characterisation of the fullerene Co-crystal C{sub 60}.SiH(C{sub 6}H{sub 5}){sub 3}; Synthese und Charakterisierung des Fulleren-Kokristallisats C{sub 60}.SiH(C{sub 6}H{sub 5}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Waidmann, G.; Jansen, M. [Bonn Univ. (Germany). Inst. fuer Anorganische Chemie

    1998-02-01

    A new fullerene co-crystal C{sub 60}.SiH(C{sub 6}H{sub 5}){sub 3} has been synthesized by crystallisation from a melt of SiH(C{sub 6}H{sub 5}){sub 3} and C{sub 60} in sealed duran tubes at 80 C. X-ray investigations led to triclinic symmetry, space group P anti 1, a = 10.086(1), b = 14.431(2), c = 14.911(2) A, {alpha} = 79.13(1), {beta} = 74.943(9), {gamma} = 88.33(1) , V = 2058.0(4) A{sup 3}, Z = 2. The crystal structure consists of isolated fullerene and silane molecules. At -80 C, C{sub 60} is still rotationally disordered. Temperature dependent Guinier powder diagrams do not show any phase transformation between 25 and -165 C. The compound is stable in air. (orig.) 17 refs.

  12. Synthesis and Crystal Structure of [Nd(η6-1,3, 5-C6H3Me3)-(AlCl4)3] (C6H6) and Structural Comparison of Ln(η6-arene)-(AlCl4)3

    Institute of Scientific and Technical Information of China (English)

    YAO,Ying-Ming; ZHANG,Yue; SHEN,Qi; LIU,Qian-Cai; MENG,Qing-Jin; LIN,Yong-Hua

    2001-01-01

    Reaction of NdCl3 with AlCl3 and mesitylene in benzene gives complex [Nd(η6-1,3,5-C6H3Me3)(AlCl4)3](C6H6) ( 1 ) which was characterized by elemental analysis, IR spectra, 0.9586(2), b=1.1717(5), c =2.8966(7) nm, β=90.85 (2)°, V=3.2529(6) nm3, Dc= 1.573 g/cm3, Z=4. A comparison of bond parameters for all the reported Ln(η6- Ar) (AlCl4)3 complexes indicates that the bond distance of Ln-C is shortened with the increasing of methyl group on benzene and with the decreasing of radius of lanthanide ions.

  13. The Aube centre. 1997 statement; Le centre de l`Aube. Bilan 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Since January 1992 the Aube centre ensures the storage of 90% of the short life radioactive wastes produced in France. This educational booklet describes the organization of the activities in the centre from the storage of wastes to the radioactivity surveillance of the environment (air, surface and ground waters, river sediments, plants and milk). (J.S.)

  14. Quantum Dots Investigated for Solar Cells

    Science.gov (United States)

    Bailey, Sheila G.; Castro, Stephanie L.; Raffaelle, Ryne P.; Hepp, Aloysius F.

    2001-01-01

    The NASA Glenn Research Center has been investigating the synthesis of quantum dots of CdSe and CuInS2 for use in intermediate-bandgap solar cells. Using quantum dots in a solar cell to create an intermediate band will allow the harvesting of a much larger portion of the available solar spectrum. Theoretical studies predict a potential efficiency of 63.2 percent, which is approximately a factor of 2 better than any state-of-the-art devices available today. This technology is also applicable to thin-film devices--where it offers a potential four-fold increase in power-to-weight ratio over the state of the art. Intermediate-bandgap solar cells require that quantum dots be sandwiched in an intrinsic region between the photovoltaic solar cell's ordinary p- and n-type regions (see the preceding figure). The quantum dots form the intermediate band of discrete states that allow sub-bandgap energies to be absorbed. However, when the current is extracted, it is limited by the bandgap, not the individual photon energies. The energy states of the quantum dot can be controlled by controlling the size of the dot. Ironically, the ground-state energy levels are inversely proportional to the size of the quantum dots. We have prepared a variety of quantum dots using the typical organometallic synthesis routes pioneered by Ba Wendi et al., in the early 1990's. The most studied quantum dots prepared by this method have been of CdSe. To produce these dots, researchers inject a syringe of the desired organometallic precursors into heated triocytlphosphine oxide (TOPO) that has been vigorously stirred under an inert atmosphere (see the following figure). The solution immediately begins to change from colorless to yellow, then orange and red/brown, as the quantum dots increase in size. When the desired size is reached, the heat is removed from the flask. Quantum dots of different sizes can be identified by placing them under a "black light" and observing the various color differences in

  15. Fluorescent Quantum Dots for Biological Labeling

    Science.gov (United States)

    McDonald, Gene; Nadeau, Jay; Nealson, Kenneth; Storrie-Lomardi, Michael; Bhartia, Rohit

    2003-01-01

    Fluorescent semiconductor quantum dots that can serve as "on/off" labels for bacteria and other living cells are undergoing development. The "on/off" characterization of these quantum dots refers to the fact that, when properly designed and manufactured, they do not fluoresce until and unless they come into contact with viable cells of biological species that one seeks to detect. In comparison with prior fluorescence-based means of detecting biological species, fluorescent quantum dots show promise for greater speed, less complexity, greater sensitivity, and greater selectivity for species of interest. There are numerous potential applications in medicine, environmental monitoring, and detection of bioterrorism.

  16. Time-bin Entanglement from Quantum Dots

    CERN Document Server

    Weihs, Gregor; Predojević, Ana

    2016-01-01

    The desire to have a source of single entangled photon pairs can be satisfied using single quantum dots as emitters. However, we are not bound to pursue only polarization entanglement, but can also exploit other degrees of freedom. In this chapter we focus on the time degree of freedom, to achieve so-called time-bin entanglement. This requires that we prepare the quantum dot coherently into the biexciton state and also build special interferometers for analysis. Finally this technique can be extended to achieve time-bin and polarization hyper-entanglement from a suitable quantum dot.

  17. Study Means of Flatness Control on 6-h CVC Mill%CVC六辊冷轧机板形控制手段的研究

    Institute of Scientific and Technical Information of China (English)

    闫学良; 刘延斌

    2013-01-01

    The function of the actuators of mechanical and thermodynamic on CVC 6 high cold rolling mills is Introduced.Analyze the means of flatness control on 6-h CVC Mill,on this basis,study the different means of flatness control between wide material and narrow material.%介绍CVC 6辊冷轧机板形控制中机械执行机构和热力学执行机构的作用,分析了6辊冷轧机的控制手段,并在此基础上研究了宽料、窄料不同的控制手段。

  18. High-pressure pyrolysis study of C sub 3 N sub 6 H sub 6 : a route to preparing bulk C sub 3 N sub 4

    CERN Document Server

    Ma, H A; Chen, L X; Zhu, P W; Guo, W L; Guo, X B; Wang, Y D; Li, S Q; Zou Guang Tian; Zhang, G; Bex, P

    2002-01-01

    In order to prepare bulk C sub 3 N sub 4 , high-pressure pyrolysis of melamine (C sub 3 N sub 6 H sub 6) at different temperatures was carried out. The products were characterized by C, N, H element analysis, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffractometry. The results of the analysis reveal that graphitic phase C sub 3 N sub 4 has been synthesized. It provides a novel route to synthesis of the theoretical superhard cubic C sub 3 N sub 4 and other C sub 3 N sub 4 phases from organic compounds by a high-pressure and high-temperature method.

  19. TDPAC study of the thermal evolution of the quadrupole parameters in NiTiF6.6H2O between 30 and 400 K

    International Nuclear Information System (INIS)

    The thermal evolution of the quadrupole parameters determined using the time differential perturbed angular correlation technique at titanium sites, in NiTiF6.6H2O is presented. The study of the thermal behavior of the hyperfine quadrupole interaction allows one to observe the occurrence of a structural phase transition around 140 K. The thermal evolution of the hyperfine quadrupole frequency of the high temperature phase was interpreted in terms of the flip motion of the water molecules through an ad hoc model. Parameters associated with the model are in good agreement with independent data obtained by Raman scattering. The agreement gives support to the model to be a valuable tool to study the dynamics of molecular groups in crystalline hydrates. (orig.)

  20. Indium Titanium Oxide Nanoparticles Induced Hepatic Damage: Hepatoprotective Role of Novel 2-Imino-4-methyl-1, 2-Dihydropyrimido [5, 4C] Quinoline-5(6H-one

    Directory of Open Access Journals (Sweden)

    Dinesh Bheeman

    2014-01-01

    Full Text Available Protective role of 2-imino-4-methyl-1, 2-dihydropyrimido [5, 4C] quinoline-5(6H-one (IMDHPQ in indium titanium oxide nanoparticles (InTiO NPs induced hepatotoxicity was analyzed. InTiO NPs were synthesized and given orally to albino rats to assess their hepatotoxicity. NPs mediated oxidative stress and liver tissue pathology were analyzed. Altered antioxidants (GSH, GPx, and catalase and, biochemical (SGOT, SGPT, ALP, total protein, and total bilirubin and histopathological changes were observed due to the oxidative stress caused by InTiO NPs. Varying effects of IMDHPQ on each parameter were observed in the present study. The altered parameters of InTiO NPs exposed rats might be due to the oxidative stress caused by NPs and hepatoprotective or ameliorative efficacy of quinoline compound IMDHPQ on signaling and molecular mechanism needs further study.

  1. Crystal structure of [Mn(1,10-C12H8N2)3](B6H7)2

    International Nuclear Information System (INIS)

    New compound [MnII(Phen)3]2+(B6H7)2- was synthesized and its crystal structure was studied by X-ray structure analysis at 100 K. Crystallographic data are: C36H38B12N6Mn, M=739.39, triclinic system, sp. gr. P 1-bar, lattice parameters: a=10.3131(3), b=13.4839(4), c=15.1132(4) A; α=97.696(1), β=108.324(1), γ=102.211(1) Deg, V=1903.9(1) A3, Z=2, dcal=1.290 g/cm3. The structure was solved by the direct and Fourier methods, and refined by full-matrix MLS in anisotropic (isotropic for hydrogen atoms) approximation to the final factor R1=0.036 for 10169 Ihkl≥2σI. The structure contains two crystallographically different anions

  2. Analysis of the effect of sidewall on the performance of 6H-SiC Schottky barrier source/drain NMOSFETs

    Institute of Scientific and Technical Information of China (English)

    Tang Xiao-Yan; Zhang Yi-Men; Zhang Yu-Ming; Gao Jin-Xia

    2004-01-01

    Between source/drain and gate of SiC Schottky barrier source/drain MOSFET (SiC SBSD-MOSFET), there must be a sidewall as isolation. The width of sidewall strongly affects on the device performance. In this paper the effect of sidewall on the performance of 6H-SiC SBSD-NMOSFET is simulated with the 2D simulator MEDICI. The simulated results show that a sidewall with width less than 0.1μm slightly affects the device performance. However, when the width of sidewall exceeds 0.1μm, the conduction does not occur until the drain voltage is high enough and saturation current sharply decreases. The effect of the sidewall on device performance can be reduced by decreasing the doping concentration in the epitaxial layer.

  3. An investigation of thin Zr films on 6H-SiC(0001) and GaN(0001) surfaces by XPS, LEED, and STM

    Science.gov (United States)

    Idczak, K.; Mazur, P.; Zuber, S.; Markowski, L.

    2016-04-01

    In this work, the results of the growth of zirconium films deposited under the ultrahigh vacuum at room temperature on the 6H-SiC(0001) and GaN(0001) surfaces were studied. Observed changes in the chemical composition, bonding environment, and surface reconstruction, and the effects of high-temperature annealing of the film are presented and discussed as well. In the performed experiment, the X-ray photoelectron spectroscopy, low-energy electron diffraction, and scanning tunneling microscopy were used. The results show that for both investigated substrates, the grown films have eminently rich and varied compositions. Besides the metallic zirconium, there are also zirconium oxides, zirconium carbides, or zirconium nitrides. The growth process proceeds according to the Volmer-Weber mode. Moreover, the zirconium-semiconductor interface does not form typical Schottky contact, but some paths with a quasi-ohmic conduction character can be observed.

  4. An investigation of thin Zr films on 6H-SiC(0001) and GaN(0001) surfaces by XPS, LEED, and STM

    Energy Technology Data Exchange (ETDEWEB)

    Idczak, K.; Mazur, P.; Zuber, S.; Markowski, L. [University of Wroclaw, Institute of Experimental Physics, Wroclaw (Poland)

    2016-04-15

    In this work, the results of the growth of zirconium films deposited under the ultrahigh vacuum at room temperature on the 6H-SiC(0001) and GaN(0001) surfaces were studied. Observed changes in the chemical composition, bonding environment, and surface reconstruction, and the effects of high-temperature annealing of the film are presented and discussed as well. In the performed experiment, the X-ray photoelectron spectroscopy, low-energy electron diffraction, and scanning tunneling microscopy were used. The results show that for both investigated substrates, the grown films have eminently rich and varied compositions. Besides the metallic zirconium, there are also zirconium oxides, zirconium carbides, or zirconium nitrides. The growth process proceeds according to the Volmer-Weber mode. Moreover, the zirconium-semiconductor interface does not form typical Schottky contact, but some paths with a quasi-ohmic conduction character can be observed. (orig.)

  5. An efficient access to the synthesis of novel 12-phenylbenzo[6,7]oxepino[3,4-b]quinolin-13(6H-one derivatives

    Directory of Open Access Journals (Sweden)

    Wentao Gao

    2012-10-01

    Full Text Available An efficient access to the tetracyclic-fused quinoline systems, 12-phenylbenzo[6,7]oxepino[3,4-b]quinolin-13(6H-one derivatives 4a–l, is described, involving the intramolecular Friedel–Crafts acylation reaction of 2-(phenoxymethyl-4-phenylquinoline-3-carboxylic acid derivatives 3a–l aided by the treatment with PPA (polyphosphoric acid or Eaton’s reagent. The required starting compound (2 was obtained by Friedländer reaction of 2-aminobenzophenone (1 with 4-chloroethylacetoacetate by using CAN (cerium ammonium nitrate, 10 mol % as catalyst at room temperature. The substrates 3a–l were prepared through one-pot reaction of ethyl 2-(chloromethyl-4-phenylquinoline-3-carboxylate (2 and substituted phenols. Our developed strategy, involving a three-step route, offers easy access to tetracyclic-fused quinoline systems in short reaction times, and the products are obtained in moderate to good yields.

  6. Investigation of a long-ranged ordered silicate adlayer on the 6H-SiC(0001) surface by LEED, AES and IPE

    Energy Technology Data Exchange (ETDEWEB)

    Aghdassi, Nabi; Ostendorf, Ralf; Zacharias, Helmut [Westfaelische Wilhelms-Universitaet Muenster (Germany)

    2008-07-01

    We have prepared well-ordered silicate adlayers on 6H-SiC(0001) surfaces by an ex situ hydrogen treatment at elevated temperatures. The generated surfaces appear to be fully passivated and therefore stable in ambient air. LEED patterns clearly feature a ({radical}(3) x {radical}(3))R30 periodicity which can be attributed to a long range order of the created oxide layers. Furthermore AES spectra exhibit a distinct O{sub KLL} peak as well as a Si{sub LVV} peak showing a typical oxidic-like shape that is indicating the presence of Si-O bonds on the surface. The unoccupied electronic states of the SiO{sub 2}/SiC interface are studied by inverse photoemission spectroscopy (IPE).

  7. Morphology and electronic properties of metal organic molecular beam epitaxy grown ZnO on hydrogen passivated 6H-SiC(0001)a)

    Science.gov (United States)

    Andres, Stefan; Pettenkofer, Christian; Speck, Florian; Seyller, Thomas

    2008-05-01

    Thin ZnO films were grown on hydrogen passivated 6H-SiC(0001) substrates by metal organic molecular beam epitaxy. The initial growth as well as the electronic properties of the growing interface were monitored by low electron diffraction and photoelectron spectroscopy (PES). From the PES intensities of the substrate and ZnO film a layered Frank-van-der-Merwe-like growth mode could be observed within the first 10nm. The ZnO films grow preferentially in (0001) direction and show a pronounced facetting in the {101¯2} direction. The experimentally determined band alignment reveals band offsets of ΔEVBM≈1.6eV and ΔECBM≈1.2eV between the valence and conduction bands, respectively. With growing ZnO thickness a band bending of about -0.51eV is observed in the SiC substrate.

  8. Production of furfural from xylose, xylan and corncob in gamma-valerolactone using FeCl3·6H2O as catalyst.

    Science.gov (United States)

    Zhang, Luxin; Yu, Hongbing; Wang, Pan; Li, Yong

    2014-01-01

    An efficient and simple one-pot monophasic reaction system with small carbon footprint for converting xylose, xylan and corncob into furfural was developed in gamma-valerolactone (GVL, an ideal sustainable solvent derived from lignocelluloses) by using FeCl3·6H2O as catalyst. Good yields of furfural from xylose were obtained, and the system was shown to work for xylan and corncob as well. A surprisingly high furfural yield of 79.6% from untreated corncob was achieved at 458 K for 100 min. Contrary to what was generally believed, the addition of water, reduced the rate of the reactions, but showed positive effect on preventing the furfural from degradation in GVL. Besides, the C6 sugars (glucose and cellulose) afforded 11.4-24.5% furfural yields when employing this catalytic approach. The reaction system proposed in this manuscript showed great potential for optimizing the catalytic process in furfural production.

  9. Theoretical studies of the optical and EPR spectra for VO^{2+} in Na_3C_6H_5O_7·2H_2O single crystal

    Directory of Open Access Journals (Sweden)

    Ch.-Y. Li

    2015-06-01

    Full Text Available On the basis of the perturbation formulas for a d^1 configuration ion in a tetragonal crystal field, the three optical absorption bands and electron paramagnetic resonance (EPR parameters (g factors g_i and hyperfine structure constants A_i for i = || and ⊥, respectively of VO^{2+} in Na_3C_6H_5O_7·2H_2O (TSCD single crystals were studied using the perturbation theory method. By simulating the calculated optical and EPR spectra to the observed values, local structure parameters and negative signs of the hyperfine structure constants A_i of the octahedral (VO_6^{8-} cluster in TSCD single crystal can be obtained.

  10. Hydrothermal Synthesis and Crystal Structure of [H4As8V14O42(H2O)]·6H2O

    Institute of Scientific and Technical Information of China (English)

    崔小兵; 徐吉庆; 李光华; 施展; 丁红; 杨国昱

    2004-01-01

    The title compound [H4As8V14O42(H2O)]·6H2O 1 has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis. It crystallizes in trigonal, space group R3c with a = b = 36.447(6), c = 21.485(5) (A), V = 24717(8) (A)3, Z = 18, Mr = 2114.66, Dc = 2.557g/cm3, F(000) = 17928, μ = 7.149 mm-1, R = 0.0792 and wR = 0.1265. The [H4As8V14O42- (H2O)] cluster consists of fourteen VO5 square pyramids linked by four As2O5 handle-like units.

  11. Learning Styles of Independent Learning Centre Users

    Directory of Open Access Journals (Sweden)

    Tarik Uzun

    2014-09-01

    Full Text Available Learning style research has been a significant field within language teaching and learning. There have been very few attempts, however, to seek possible links between independent learning and learning style preferences. This paper aims to identify the learning styles of students who use the Independent Learning Centre (ILC on a regular basis at a state university in Turkey (n=102. The findings of the learning style analysis revealed that, contrary to expectations, most of the regular users of the centre were synoptic learners, which implies that these learners might not necessarily have conscious control over their own learning processes. An in-depth analysis of learning styles and recommendations to improve the services offered in the centre are also included in the paper.

  12. Occupational deprivation in an asylum centre:

    DEFF Research Database (Denmark)

    Morville, Anne-Le; Erlandsson, Lena-Karin

    2013-01-01

    This article presents a study of three asylum-seeking men from Iran and Afghanistan. It aimed to explore how and if they experienced occupations as occupations in a Danish asylum centre and how their life experience shaped their choice and value of current occupations. In-depth narrative interviews...... explored the participants’ occupational history and its influence on their occupations in the asylum centre. A thematic analysis showed that the participants had been subjected to occupational disruption and deprivation by politically oppressive systems even before their flight. Their occupations...... in Denmark were to a certain extent influenced by their earlier occupations and the current occupational deprivation they all experienced was due to limited possibilities in the centre. Although they tried their best to fill their days and create structure, there was a loss of valued occupations...

  13. A day in the CERN Control Centre

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    The CERN Control Centre (CCC) is the nerve centre of the CERN beam systems. From this room, the experts prepare, monitor, adjust, and control the particle beams that circulate throughout the accelerator complex while ensuring that the services and the technical infrastructure work flawlessly. Buttons, screens, telephones, lights (but no sound): in the CCC, everything is ready to make it possible for the LHC to reach the unprecedented energies expected at Run 2.   Seen from above, the CERN Control Centre resembles the shape of a quadrupole magnet. The consoles are distributed in four circles, called “islands”, dedicated to the LHC, the SPS, the PS Complex and the Technical Infrastructure (TI) respectively. Spread between TI and LHC are the Cryogenics consoles. Being in the same room allows the 24h-manned islands to be constantly in touch with one another, thus ensuring the best performance of the machines. At the LHC island, operators are currently busy training the magnet...

  14. Temperature dependent behavior of localized and delocalized electrons in nitrogen-doped 6H SiC crystals as studied by electron spin resonance

    International Nuclear Information System (INIS)

    We have studied the temperature behavior of the electron spin resonance (ESR) spectra of nitrogen (N) donors in n-type 6H SiC crystals grown by Lely and sublimation sandwich methods (SSM) with donor concentration of 1017 cm−3 at T = 60–150 K. A broad signal in the ESR spectrum was observed at T ≥ 80 K with Lorentzian lineshape and g|| = 2.0043(3), g⊥ = 2.0030(3), which was previously assigned in the literature to the N donors in the 1s(E) excited state. Based on the analysis of the ESR lineshape, linewidth and g-tensor we attribute this signal to the conduction electrons (CE). The emergence of the CE ESR signal at T > 80 K was explained by the ionization of electrons from the 1s(A1) ground and 1s(E) excited states of N donors to the conduction band while the observed reduction of the hyperfine (hf) splitting for the Nk1,k2 donors with the temperature increase is attributed to the motional narrowing effect of the hf splitting. The temperature dependence of CE ESR linewidth is described by an exponential law (Orbach process) with the activation energy corresponding to the energy separation between 1s(A1) and 1s(E) energy levels for N residing at quasi-cubic sites (Nk1,k2). The theoretical analysis of the temperature dependence of microwave conductivity measured by the contact-free method shows that due to the different position of the Fermi level in two samples the ionization of free electrons occurs from the energy levels of Nk1,k2 donors in Lely grown samples and from the energy level of Nh residing at hexagonal position in 6H SiC grown by SSM

  15. Enhancing person-centred communication in NICU

    DEFF Research Database (Denmark)

    Weis, Janne; Zoffmann, Vibeke; Egerod, Ingrid

    2015-01-01

    Aims of this article were (a) to explore how parents of premature infants experience guided family-centred care (GFCC), and (b) to compare how parents receiving GFCC versus standard care (SC) describe nurse-parent communication in the neonatal intensive care unit.......Aims of this article were (a) to explore how parents of premature infants experience guided family-centred care (GFCC), and (b) to compare how parents receiving GFCC versus standard care (SC) describe nurse-parent communication in the neonatal intensive care unit....

  16. Imperial College Reactor Centre annual report. 1984

    International Nuclear Information System (INIS)

    The following new equipment is noted; for atomic absorption spectrometry to supplement the neutron activation analysis, and an additional nuclear data analysis system to improve the quality and speed of the service to users of the Centre's facilities. Users include undergraduates from the University of London, outside bodies such as the British Musueum, as well as departments of Colleges of the University of London. The reactor lost only three days through failures or faults. Two replacement fuel elements were put into the reactor during the year. The report contains brief accounts of 34 research programmes at the Centre. (U.K.)

  17. A study on socio-demographic profile and feasibility of DOTS provider registered under RNTCP in Varanasi district Uttar Pradesh

    Directory of Open Access Journals (Sweden)

    Mohd. Afzalul Haque

    2014-03-01

    Full Text Available Introduction: Tuberculosis is a major chronic disorder affecting the larger population more than any other disease in the country. DOTS was introduced in India in 1993 as part of the Revised National Tuberculosis Programme (RNTCP following a review of India’s National Tuberculosis Programme (NTP a year earlier (1 .Patient satisfaction is an important parameter for assessing the quality of patient care services. There is need to assess the health care provider regarding the consumer satisfaction as often as possible, this paper summarizes our experience about role of DOTS provider in the management of TB patient in rural population of Varanasi districts Utter Pradesh. Objective: (1 To assess the perception of registered tuberculosis patients regarding DOTS provider for the treatment of tuberculosis. (2 To assess the accessibility, acceptability & availability of community DOTS provider. Design: A longitudinal study. Setting: Three microscopic centre of Cholapur Tuberculosis unit of Varanasi districts. Methods: Registered patients were interviewed twice: once in the beginning and another at the completion of the treatment or after the permanent discontinuation of the treatment. Patients were interviewed for their socio-demographic profiles, opinion about DOTS and its providers. Side effects experienced and action taken etc. Data was collected on a semi-structured, pre-tested questionnaire. DOTS providers were interviewed and treatment cards analyzed for any interruption of treatment and action taken. Data was collected from 1st June 2004 to 31th June 2005 till the completion of the regimen. Results: Majority of DOTS providers were young males (82.7% of 26 years to 40 years, while the representation of females was only 5 (17.3%. Almost more than 80% of the patients started their treatment within 1-10 days. For majority of cases (83% the distance of DOTS provider from patient’s house was within 1 km. Mean time spent to go to DOTS provider was 27

  18. An evaluation of the dot-ELISA procedure as a diagnostic test in an area with a high prevalence of human Toxocara canis infection

    Directory of Open Access Journals (Sweden)

    María V Bojanich

    2012-03-01

    Full Text Available The aim of this work was to evaluate a dot-enzyme-linked immunosorbent assay (dot-ELISA using excretory-secretory antigens from the larval stages of Toxocara canis for the diagnosis of toxocariasis. A secondary aim was to establish the optimal conditions for its use in an area with a high prevalence of human T. canis infection. The dot-ELISA test was standardised using different concentrations of the antigen fixed on nitrocellulose paper strips and increasing dilutions of the serum and conjugate. Both the dot-ELISA and standard ELISA methods were tested in parallel with the same batch of sera from controls and from individuals living in the problem area. The best results were obtained with 1.33 µg/mL of antigen, dilutions of 1/80 for the samples and controls and a dilution of 1/5,000 for the anti-human IgG-peroxidase conjugate. All steps of the procedure were performed at room temperature. The coincidence between ELISA and dot-ELISA was 85% and the kappa index was 0.72. The dot-ELISA test described here is rapid, easy to perform and does not require expensive equipment. Thus, this test is suitable for the serological diagnosis of human T. canis infection in field surveys and in the primary health care centres of endemic regions.

  19. Synthesis and structure of the extended phosphazane ligand [(1,4-C6H4){N(μ-PN(t)Bu)2N(t)Bu}2](4).

    Science.gov (United States)

    Sevilla, Raquel; Less, Robert J; García-Rodríguez, Raúl; Bond, Andrew D; Wright, Dominic S

    2016-02-01

    The reaction of the phenylene-bridged precursor (1,4-C6H4)[N(PCl2)2]2 with (t)BuNH2 in the presence of Et3N gives the new ligand precursor (1,4-C6H4)[N(μ-N(t)Bu)2(PNH(t)Bu)2]2, deprotonation of which with Bu2Mg gives the novel tetraanion [(1,4-C6H4){N(μ-N(t)Bu)2(PN(t)Bu)2}2](4-).

  20. Suzuki-Miyaura, Mizoroki-Heck carbon-carbon coupling and hydrogenation reactions catalysed by PdII and RhI complexes containing cyclodiphosphazane cis-{tBuNP(OC6H4OMe-)}2

    Indian Academy of Sciences (India)

    Sasmita Mohanty; Maravanji S Balakrishna

    2010-03-01

    The catalytic activity of the palladium complex cis-[PdCl2{(tBuNP(OC6H4OMe-))2- }2] (2) containing cis-{tBuNP(OC6H4OMe-)}2 (1) in Suzuki-Miyaura and Mizoroki-Heck carbon-carbon cross coupling reactions is described. The compound 2 also displays very high activity in Mizoroki-Heck coupling reactions. The rhodium(I) complex [RhCl(COD){(tBuNP(OC6H4OMe-))2- }] (3) acts as an excellent catalyst for the hydrogenation of several terminal olefins.

  1. Large quantum dots with small oscillator strength

    DEFF Research Database (Denmark)

    Stobbe, Søren; Schlereth, T.W.; Höfling, S.;

    2010-01-01

    We have measured the oscillator strength and quantum efficiency of excitons confined in large InGaAs quantum dots by recording the spontaneous emission decay rate while systematically varying the distance between the quantum dots and a semiconductor-air interface. The size of the quantum dots...... is measured by in-plane transmission electron microscopy and we find average in-plane diameters of 40 nm. We have calculated the oscillator strength of excitons of that size assuming a quantum-dot confinement given by a parabolic in-plane potential and a hard-wall vertical potential and predict a very large...... oscillator strength due to Coulomb effects. This is in stark contrast to the measured oscillator strength, which turns out to be so small that it can be described by excitons in the strong confinement regime. We attribute these findings to exciton localization in local potential minima arising from alloy...

  2. Ge Quantum Dot Infrared Imaging Camera Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna Innovations Incorporated proposes to develop a high performance Ge quantum dots-based infrared (IR) imaging camera on Si substrate. The high sensitivity, large...

  3. Spin current in double quantum dot

    Institute of Scientific and Technical Information of China (English)

    Zhao Hua; Zhang Guo-Feng; Yin Wen; Liang Jiu-Qing

    2004-01-01

    We have studied the dynamical behaviours of two electrons confined in a double quantum dot driven by rotating magnetic fields in terms of the theory of Lewis-Riesenfeld Hermitian invariants for the explicitly time-dependent Hamiltonian. The coherent spin oscillations in the dot provide a generation source for spin current. Exact solutions obtained allow us to investigate the dynamical properties of the spin localization for various initial localized states.

  4. Magnetic quantum dots and magnetic edge states

    International Nuclear Information System (INIS)

    Starting with defining the magnetic edge state in a magnetic quantum dot, which becomes quite popular nowadays conjunction with a possible candidate for a high density memory device or spintronic materials, various magnetic nano-quantum structures are reviewed in detail. We study the magnetic edge states of the two dimensional electron gas in strong perpendicular magnetic fields. We find that magnetic edge states are formed along the boundary of the magnetic dot, which is formed by a nonuniform distribution of magnetic fields. These magnetic edge states circulate either clockwise or counterclockwise, depending on the number of missing flux quanta, and exhibit quite different properties, as compared to the conventional ones which are induced by electrostatic confinements in the quantum Hall system. We also find that a close relation between the quantum mechanical eigenstates and the classical trajectories in the magnetic dot. When a magnetic dot is located inside a quantum wire, the edge-channel scattering mechanism by the magnetic quantum dot is very different from that by electrostatic dots. Here, the magnetic dot is formed by two different magnetic fields inside and outside the dot. We study the ballistic edge-channel transport and magnetic edge states in this situation. When the inner field is parallel to the outer one, the two-terminal conductance is quantized and shows the features of a transmission barrier and a resonator. On the other hand, when the inner field is reversed, the conductance is not quantized and all channels can be completely reflected in some energy ranges. The difference between the above two cases results from the distinct magnetic confinements. We also describe successfully the edge states of magnetic quantum rings and others in detail

  5. Coherent scattering in a small quantum dot

    International Nuclear Information System (INIS)

    Ballistic transport in an open small (100 nm) three-terminal quantum dot based on the high-mobility two-dimensional electron gas of the AlGaAs/GaAs heterojunction has been analyzed. It has been shown that the gate oscillations of resistance of such a dot arise due to the coherent scattering of electrons on its quasidiscrete levels being suppressed by a weak magnetic field

  6. Exploring Extragalactic Emission: The Hα Dot Survey

    Science.gov (United States)

    Rampalli, Rayna; Salzer, John Joseph

    2016-01-01

    The Hα Dot Survey was established as a result of finding point sources of strong line emission in the data obtained for the ALFALFA Hα Survey (Van Sistine et al. 2015). In the latter survey, broad-band R and narrow-band Hα filters were used to examine target galaxies from the ALFALFA blind HI survey (Giovanelli et al. 2005, Haynes et al. 2011). In the process of reducing the ALFALFA Hα Survey data the "Hα Dots" were discovered (Kellar et al. 2008, 2012). Using specialized image analysis tools, a large population of dots has already been detected in the more than 1500 ALFALFA Hα narrow-band images taken with the 0.9m WIYN and 2.1m KPNO telescopes. Follow-up spectra of over 200 Hα Dots discovered from the 0.9m images reveal that these objects are a mix of nearby low-luminosity star-forming galaxies, compact starbursts and Seyfert 2 galaxies at intermediate redshifts, and high-redshift QSOs. Here we present the first list of Hα Dots detected using 2.1m telescope data. The 2.1m images yield a sample of Dots that average almost two magnitudes fainter than those detected with the 0.9m. The current REU project is designed to characterize the set of Hα Dots detected in the deeper 2.1m telescope images, while the broad goals of the Hα Dot Survey include the desire to understand better the chemical evolution of galaxies over cosmic time. This project was supported in part by the NSF REU grant 1358980, by the Maria Mitchell Association (Nantucket, MA), and by the Massachusetts Space Grant Consortium.

  7. [The coordination of care in health centres].

    Science.gov (United States)

    Ribardière, Olivia

    2016-06-01

    Health centres are structurally designed to facilitate the coordination of care. However, evolutions in society have resulted in forms of consumption of health care which are not necessarily compatible with efficient care coordination. On a local level, teams are nevertheless organising and structuring themselves to offer the right form of care, to the right patient and at the right time. PMID:27338687

  8. Renovation of the CERN Computer Centre

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The Computer Centre at CERN is seen after half of the equipment is the large ground floor room has been removed. A large-scale spring-cleaning operation took place before renovation work for the new CERN Grid system began. Fifteen kilometres of cables that were no longer needed were removed from the cavity floor for recycling.

  9. The Australian Centre for Minesite Rehabilitation Research

    International Nuclear Information System (INIS)

    The Australian Centre for Minesite Rehabilitation Research (ACMRR) is a joint venture between the Australian mining industry through the Australian Mineral Industries Research Association Ltd. (AMIRA) and three of the organizations working most actively in this area in Australia: CSIRO Minesite Rehabilitation Research Program; University of Queensland Centre for Mined Land Rehabilitation; and Curtin University Mulga Research Centre. The ACMRR was established in July 1993 to provide a national framework to conduct Strategic Research into minesite rehabilitation. It is an industry led and funded initiative. The Goals of the Centre include: to conduct strategic research into minesite rehabilitation to provide sustainable environmental solutions which are acceptable to industry, government and the community; to be recognized as a center of excellence undertaking commissioned research on minesite rehabilitation in an independent and thorough manner; to provide scientific and technological foundations to facilitate industry and government in setting acceptable standards; to act as networking and communications focus; and to enhance education and training in minesite rehabilitation. Strategic Research Programs in: Water Systems--downstream surface and groundwater quality; Land--the long-term behavior and stability of constructed landforms; Ecosystems--the long-term sustainability of constructed landforms; Waste--the long-term treatment and disposal of waste products; will allow the ACMRR to achieve these goals through specific research projects in these areas, developed with industry sponsors. This paper will discuss their progress to date, research projects underway, and plans for the future

  10. Interorganisatorisk styring i Shared Service Centre

    DEFF Research Database (Denmark)

    Harritz, Daniel

    2011-01-01

    I den offentlige sektor er der en stigende udbredelse af Shared Service Centre (SSC). Men der er endnu meget lidt viden om de interorganisatoriske styringsproblemstillinger, der opstår når et SSC oprettes. I denne artikel præsenteres, ud fra et interorganisatorisk perspektiv, en styringsramme der...

  11. [The coordination of care in health centres].

    Science.gov (United States)

    Ribardière, Olivia

    2016-06-01

    Health centres are structurally designed to facilitate the coordination of care. However, evolutions in society have resulted in forms of consumption of health care which are not necessarily compatible with efficient care coordination. On a local level, teams are nevertheless organising and structuring themselves to offer the right form of care, to the right patient and at the right time.

  12. In the Field: The Canadian Ecology Centre.

    Science.gov (United States)

    Magee, Clare

    2000-01-01

    The Canadian Ecology Centre (Ontario) offers year-round residential and day programs in outdoor and environmental education for secondary students, field placement and internship opportunities for college students, and ecotourism programs, while providing employment and tax revenues to the local community. Dubbed consensus environmentalism, the…

  13. Centring the Subject in Order to Educate

    Science.gov (United States)

    Webster, R. Scott

    2007-01-01

    It is important for educators to recognise that the various calls to decentre the subject--or self--should not be interpreted as necessarily requiring the removal of the subject altogether. Through the individualism of the Enlightenment the self was centred. This highly individualistic notion of the sovereign self has now been decentred especially…

  14. The fragility of human-centred design

    NARCIS (Netherlands)

    Steen, M.G.D.

    2008-01-01

    In human-centred design (HCD), researchers and designers develop products in cooperation with the potential users of these products. They attempt to give users a voice or a role in their projects, with the intention of developing products that match users' needs and preferences. This approach is esp

  15. Student-Centred Learning: A Humanist Perspective

    Science.gov (United States)

    Tangney, Sue

    2014-01-01

    The notion of student-centred learning is often not defined; within the pedagogic literature it is generally associated with constructivism or principles associated with a constructivist environment such as building on prior knowledge, purposeful active learning and sense-making. An informal enquiry into conceptions of university staff prior to…

  16. The young centre of the Earth

    DEFF Research Database (Denmark)

    Uggerhøj, Ulrik Ingerslev; Mikkelsen, Rune E.; Faye, Jan

    2016-01-01

    We treat, as an illustrative example of gravitational time dilation in relativity, the observation that the centre of the Earth is younger than the surface by an appreciable amount. Richard Feynman first made this insightful point and presented an estimate of the size of the effect in a talk...

  17. Quantum-dot-in-perovskite solids

    KAUST Repository

    Ning, Zhijun

    2015-07-15

    © 2015 Macmillan Publishers Limited. All rights reserved. Heteroepitaxy - atomically aligned growth of a crystalline film atop a different crystalline substrate - is the basis of electrically driven lasers, multijunction solar cells, and blue-light-emitting diodes. Crystalline coherence is preserved even when atomic identity is modulated, a fact that is the critical enabler of quantum wells, wires, and dots. The interfacial quality achieved as a result of heteroepitaxial growth allows new combinations of materials with complementary properties, which enables the design and realization of functionalities that are not available in the single-phase constituents. Here we show that organohalide perovskites and preformed colloidal quantum dots, combined in the solution phase, produce epitaxially aligned \\'dots-in-a-matrix\\' crystals. Using transmission electron microscopy and electron diffraction, we reveal heterocrystals as large as about 60 nanometres and containing at least 20 mutually aligned dots that inherit the crystalline orientation of the perovskite matrix. The heterocrystals exhibit remarkable optoelectronic properties that are traceable to their atom-scale crystalline coherence: photoelectrons and holes generated in the larger-bandgap perovskites are transferred with 80% efficiency to become excitons in the quantum dot nanocrystals, which exploit the excellent photocarrier diffusion of perovskites to produce bright-light emission from infrared-bandgap quantum-tuned materials. By combining the electrical transport properties of the perovskite matrix with the high radiative efficiency of the quantum dots, we engineer a new platform to advance solution-processed infrared optoelectronics.

  18. Coherent transport through interacting quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Hiltscher, Bastian

    2012-10-05

    The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

  19. New hypodiphosphates of the alkali metals: Synthesis, crystal structure and vibrational spectra of the hypodiphosphates(IV) M{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (M=Rb and Cs)

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Peng [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany); Wiegand, Thomas; Eckert, Hellmut [Institut fuer Physikalische Chemie and Graduate School of Chemistry, Westfaelische Wilhelms-Universitaet Muenster, Corrensstr. 28/30, D-48149 Muenster (Germany); Gjikaj, Mimoza, E-mail: mimoza.gjikaj@tu-clausthal.de [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany)

    2012-10-15

    The new hypodiphosphates(IV) Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (1) and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (2) were synthesized by soft chemistry reactions from aqueous solutions of hypophosphoric acid and the corresponding heavy alkali-metal carbonates. Their crystal structures were determined by single crystal X-ray diffraction. Both compounds crystallize isotypic in the triclinic space group P-1 with one formula unit in the unit cell. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units in staggered conformation for the P{sub 2}O{sub 6} skeleton and the corresponding alkali-metal cations. In the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} ion the hydrogen atoms are in a 'trans-trans' conformation. O{center_dot}H-O hydrogen bonds between the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups consolidate the structures into a three-dimensional network. The FT-Raman and {sup 31}P and {sup 1}H and MAS NMR spectra of the title compounds have been recorded and interpreted, especially with respect to their assignment to the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups. Thermogravimetric data of 2 have been interpreted in terms of a thermal decomposition model. - Graphical Abstract: The layered compounds Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] have been synthesized and investigated. Both crystallize isotypic. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units and the corresponding alkali-metal cations. Highlights: Black-Right-Pointing-Pointer Synthesis and single-crystal structure of new alkali hypodiphosphates. Black-Right-Pointing-Pointer Structures are characterized by [(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})]{sup 2-} units and M

  20. Treatment Outcomes of Patients Placed on Treatment Under Directly Observed Therapy Short-Course (Dots)

    Science.gov (United States)

    Kaur, Gurpreet; Goel, N.K.; Kumar, Dinesh; Janmeja, A.K.; Swami, H.M.; Kalia, Meenu

    2008-01-01

    Background: Tuberculosis continues to be a pressing health problem in India. The Revised National Tuberculosis Programme (RNTCP), an application of Directly Observed Treatment Short-course (DOTS) in India, launched in 1997 needs continuous evaluation. Objective: To study the outcomes of treatment among the patients put on DOTS under RNTCP in Chandigarh, UT. Material & Methods: A Longitudinal study was conducted during 2004-2005 in 13 Microscopic centres (MC's) spread over 2 Tuberculosis Units (TU's) under District Tuberculosis Centre (DTC) in Union Territory (UT), Chandigarh. A sample of 265 respondents, selected by two-stage stratified random sampling technique, was recruited in the study cohort. Data analysis was done using SPSS-10 statistical software package. Results: For Category I and Category II patients, the Success rate was 98.6% and 90.4% respectively. The overall default rate was 1.1% and failure rate was 2.6%. For re-treatment cases, failure rate was higher i.e. 5.8%. The sputum conversion rate among the new smear positive cases was 93.8% at 3 months of treatment. For the re-treatment cases, spu-tum conversion rate at 3 months was 94.1%. Conclusion: The study concludes that RNTCP is running successfully in UT Chandigarh, having high success rate and low default rate. The reasons for high failure rate should be explored in depth. PMID:20165654

  1. Treatment outcomes of patients placed on treatment under directly observed therapy short-course (DOTS

    Directory of Open Access Journals (Sweden)

    Kaur Gurpreet

    2008-01-01

    Full Text Available Background : Tuberculosis continues to be a pressing health problem in India. The Revised National Tuberculosis Programme (RNTCP, an application of Directly Observed Treatment Short-course (DOTS in India, launched in 1997 needs contin-uous evaluation. Objective : To study the outcomes of treatment among the patients put on DOTS under RNTCP in Chandigarh, UT. Material & Methods : A Longitudi-nal study was conducted during 2004-2005 in 13 Microscopic centres (MC′s spread over 2 Tuberculosis Units (TU′s under District Tuberculosis Centre (DTC in Union Territory (UT, Chandigarh. A sample of 265 respondents, selected by two-stage stratified random sampling technique, was recruited in the study cohort. Data analysis was done using SPSS-10 statistical software package. Results : For Category I and Category II patients, the Success rate was 98.6% and 90.4% respectively. The overall default rate was 1.1% and failure rate was 2.6%. For re-treatment cases, failure rate was higher i.e. 5.8%. The sputum conversion rate among the new smear positive cases was 93.8% at 3 months of treatment. For the re-treatment cases, spu-tum conversion rate at 3 months was 94.1%. Conclusion : The study concludes that RNTCP is running successfully in UT Chandigarh, having high success rate and low default rate. The reasons for high failure rate should be explored in depth.

  2. Dot-dye-immunoassay for the diagnosis of schistosomiasis mansoni

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Teles Rabello

    1992-06-01

    Full Text Available A new serological assay dot-dye-immunoassay (dot-DIA was evaluated for the diagnosis of schistosomiasis mansoni. This method consist of four steps: (a biding of antigens to a nitrocellulose membrane (NC; (b blocking of free sites of the NC; (c incubation in specific primary antibody; (d detection of primary antibody reactivity by color development using second antibody coupled to textile dyes. Sera from 82 individuals, 61 with Schistosoma mansoni eggs in the stool and 21 stool negative were tested by ELISA, dot-ELISA, and dotDIA. A high level of agreement between the methods tested was observed for all sera tested: ELISA x dot-ELISA: 95.1%, ELISA x dot-DIA: 92.7% and dot-ELISA x dot-DIA: 97.6%. In this study, dot-DIA proved to be a feasible, sensitive, rapid and practical test for the diagnosis of shcistosomiasis.

  3. Person-centred care in nursing documentation.

    LENUS (Irish Health Repository)

    Broderick, Margaret C

    2012-12-07

    BACKGROUND: Documentation is an essential part of nursing. It provides evidence that care has been carried out and contains important information to enhance the quality and continuity of care. Person-centred care (PCC) is an approach to care that is underpinned by mutual respect and the development of a therapeutic relationship between the patient and nurse. It is a core principle in standards for residential care settings for older people and is beneficial for both patients and staff (International Practice Development in Nursing and Healthcare, Chichester, Blackwell, 2008 and The Implementation of a Model of Person-Centred Practice in Older Person Settings, Dublin, Health Service Executive, 2010a). However, the literature suggests a lack of person-centredness within nursing documentation (International Journal of Older People Nursing 2, 2007, 263 and The Implementation of a Model of Person-Centred Practice in Older Person Settings, Dublin, Health Service Executive, 2010a). AIMS AND OBJECTIVES: To explore nursing documentation in long-term care, to determine whether it reflected a person-centred approach to care and to describe aspects of PCC as they appeared in nursing records. METHOD: A qualitative descriptive study using the PCN framework (Person-centred Nursing; Theory and Practice, Oxford, Wiley-Blackwell, 2010) as the context through which nursing assessments and care plans were explored. RESULTS: Findings indicated that many nursing records were incomplete, and information regarding psychosocial aspects of care was infrequent. There was evidence that nurses engaged with residents and worked with their beliefs and values. However, nursing documentation was not completed in consultation with the patient, and there was little to suggest that patients were involved in decisions relating to their care. IMPLICATIONS FOR PRACTICE: The structure of nursing documentation can be a major obstacle to the recording of PCC and appropriate care planning. Documentation

  4. Nuclear Electric Visitor Centres - Innovation and inspiration

    International Nuclear Information System (INIS)

    Full text: This eight minute video demonstrates the approach taken by Nuclear Electric to exhibitions that are open to the public. The information is given both visually - with excerpts from some of the attractions on display at the centres - and in comments from interviews with visitors, the centre guides and the man responsible for many of the exhibits featured in the video. on one side are the schoolchildren who are visiting the exhibition and are seen both playing and learning as they press buttons, watch videos, 'meet' Michael Faraday, and learn about radiation - its disposal and its safe transportation. The headmaster of the school is interviewed and explains that the exhibition is helping his children understand the importance of electricity to their world. on the other side is Jackie Lucas, the visitor centre manager, explaining what the public make of the exhibition. We see her staff greeting the children and helping them to understand the show. The designer of the exhibition, Len Upton explains how you go about making an exhibition such as this both informative and fun. Also interviewed is the man behind many of the exhibitions featured at Nuclear Electric's visitor centres up and down the country, Nicholas Mullane. He explains the purpose of the exhibition and what messages it imparts. The video is presented in split-screen or composite format, whereby the interviewee and children are often presented together. Excerpts from the various videos on display are presented as both how they are seen from the floor, as well as the full screen effect of the various programmes. The video gives much of the feeling of fun to be gained at the exhibition, as well as showing the educational benefits to be gained from a couple of hours at one of Nuclear Electric's visitor centres. Copies of the video can be obtained from Bob Fenton at Nuclear Electric. (Fax: ++44 1 452 652 443). (author)

  5. A new structure to increase the photostability of CdTe quantum dot sensitized solar cells

    International Nuclear Information System (INIS)

    In this paper a new cell structure is introduced to reduce the rate of CdTe corrosion in quantum dot sensitized solar cells (QDSSCs) using I-/I3- electrolyte. In this cell, one electrode is a titania nanorod that was sensitized with CdTe quantum dots as the working electrode. A thin gold layer is sputtered on the electrode to act as a protective layer against the I-/I3- corrosive electrolyte and to passivate the CdTe surface traps which are the main recombination centres in a QDSSC. In addition, a Schottky barrier formed at the interface of Au and CdTe prevents direct electron recombination from the CdTe conduction band with I3- ions. The mechanism of charge transfer and quantum dot regeneration in the presence of gold layer is discussed and our results show that the solar cells made of TiO2/CdTe/Au photoanode have more photostability and a higher fill factor relative to the TiO2/CdTe photoanodes.

  6. Temperature dependent behavior of localized and delocalized electrons in nitrogen-doped 6H SiC crystals as studied by electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Savchenko, D., E-mail: dariyasavchenko@gmail.com [Institute of Physics AS CR, Prague 182 21 (Czech Republic); National Technical University of Ukraine “Kyiv Polytechnic Institute”, Kyiv 03056 (Ukraine); Kalabukhova, E.; Shanina, B.; Kiselov, V. [V.E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv 03028 (Ukraine); Cichoň, S.; Honolka, J. [Institute of Physics AS CR, Prague 182 21 (Czech Republic); Mokhov, E. [A.F. Ioffe Physical Technical Institute, RAS, St. Petersburg 194021 (Russian Federation); Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg 19710 (Russian Federation)

    2016-01-28

    We have studied the temperature behavior of the electron spin resonance (ESR) spectra of nitrogen (N) donors in n-type 6H SiC crystals grown by Lely and sublimation sandwich methods (SSM) with donor concentration of 10{sup 17 }cm{sup −3} at T = 60–150 K. A broad signal in the ESR spectrum was observed at T ≥ 80 K with Lorentzian lineshape and g{sub ||} = 2.0043(3), g{sub ⊥} = 2.0030(3), which was previously assigned in the literature to the N donors in the 1s(E) excited state. Based on the analysis of the ESR lineshape, linewidth and g-tensor we attribute this signal to the conduction electrons (CE). The emergence of the CE ESR signal at T > 80 K was explained by the ionization of electrons from the 1s(A{sub 1}) ground and 1s(E) excited states of N donors to the conduction band while the observed reduction of the hyperfine (hf) splitting for the N{sub k1,k2} donors with the temperature increase is attributed to the motional narrowing effect of the hf splitting. The temperature dependence of CE ESR linewidth is described by an exponential law (Orbach process) with the activation energy corresponding to the energy separation between 1s(A{sub 1}) and 1s(E) energy levels for N residing at quasi-cubic sites (N{sub k1,k2}). The theoretical analysis of the temperature dependence of microwave conductivity measured by the contact-free method shows that due to the different position of the Fermi level in two samples the ionization of free electrons occurs from the energy levels of N{sub k1,k2} donors in Lely grown samples and from the energy level of N{sub h} residing at hexagonal position in 6H SiC grown by SSM.

  7. Realistic model of a vertical pillar quantum dot: Analysis of individual dot data

    NARCIS (Netherlands)

    Maksym, P.A.; Nishi, Y.; Austing, D.G.; Hatano, T.; Kouwenhoven, L.P.; Aoki, H.; Tarucha, S.

    2009-01-01

    An accurate model of a vertical pillar quantum dot is described. The full three-dimensional structure of the device containing the dot is taken into account and this leads to an effective two-dimensional model in which electrons move in the two lateral dimensions, the confinement is parabolic, and t

  8. Diorganoruthenium Complexes Incorporating Noninnocent [C6H2(CH2ER2)2-3,5]22- (E=N, P) Bis-Pincer Bridging Ligands: Synthesis, Spectroelectrochemistry, and DFT Studies

    NARCIS (Netherlands)

    Gagliardo, M.; Amijs, C.H.M.; Lutz, M.; Spek, A.L.; Havenith, R.W.A.; Hartl, F.; van Klink, G.P.M.; van Koten, G.

    2007-01-01

    The dinuclear complex [(tpy)RuII(PCP?PCP)RuII(tpy)]Cl2 (bridging PCP-PCP ) 3,3',5,5'-tetrakis(diphenylphosphinomethyl) biphenyl, [C6H2(CH2PPh2)2-3,5]2 2-) was prepared via a transcyclometalation reaction of the bis-pincer ligand [PC(H)P-PC(H)P] and the Ru(II) precursor [Ru(NCN)(tpy)]Cl (NCN ) [C6H3(

  9. Synthesis of the Sterically Related Nickel Gallanediyl Complexes [Ni(CO)3(GaAr′)] (Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2) and [Ni(CO)3(GaL)] (L = HC[C(CH3)N(C6H3-2,6-iPr2)]2): Thermal Decomposition of [Ni(CO)3(GaAr′)] to give the Cluster [Ni4(CO)7(GaAr′)3

    OpenAIRE

    Serrano, Oracio; Hoppe, Elke; Power, Philip P.

    2010-01-01

    Reaction of Ni(CO)4 in toluene at room temperature with one equivalent of GaAr′ (Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2) and GaL (L = HC[C(Me)N(C6H3-2,6-iPr2)]2) formed the mono-substituted Ni(CO)3(GaAr′) (1) and Ni(CO)3(GaL) (3), respectively. Compound 1 decomposed under reduced pressure or upon heating in toluene to give the new cluster species Ni4(CO)7(GaAr′)3 (2). Reaction of 3 with a second equivalent of GaL in toluene at 95 °C afforded the disubstituted complex Ni(CO)2(GaL)2 (4). All the compo...

  10. Submonolayer Quantum Dot Infrared Photodetector

    Science.gov (United States)

    Ting, David Z.; Bandara, Sumith V.; Gunapala, Sarath D.; Chang, Yia-Chang

    2010-01-01

    A method has been developed for inserting submonolayer (SML) quantum dots (QDs) or SML QD stacks, instead of conventional Stranski-Krastanov (S-K) QDs, into the active region of intersubband photodetectors. A typical configuration would be InAs SML QDs embedded in thin layers of GaAs, surrounded by AlGaAs barriers. Here, the GaAs and the AlGaAs have nearly the same lattice constant, while InAs has a larger lattice constant. In QD infrared photodetector, the important quantization directions are in the plane perpendicular to the normal incidence radiation. In-plane quantization is what enables the absorption of normal incidence radiation. The height of the S-K QD controls the positions of the quantized energy levels, but is not critically important to the desired normal incidence absorption properties. The SML QD or SML QD stack configurations give more control of the structure grown, retains normal incidence absorption properties, and decreases the strain build-up to allow thicker active layers for higher quantum efficiency.

  11. Measurement of Eccentricity of the Centre of Mass from the Geometric Centre of a Sphere

    Institute of Scientific and Technical Information of China (English)

    郭俊起; 胡忠坤; 顾邦明; 罗俊

    2004-01-01

    The eccentricity of the centre of mass from the geometric centre of a spherical attracting mass in determining the Newtonian gravitational constant G is tested by means of an electronic balance. The experimental result shows that the eccentricity of the sample is about 0.31 μm with uncertainty of 0.05 μm. Two density distribution models are discussed to estimate the uncertainty to G by the eccentricities of the attracting masses.

  12. Understanding electronic systems in semiconductor quantum dots

    Science.gov (United States)

    Ciftja, Orion

    2013-11-01

    Systems of confined electrons are found everywhere in nature in the form of atoms where the orbiting electrons are confined by the Coulomb attraction of the nucleus. Advancement of nanotechnology has, however, provided us with an alternative way to confine electrons by using artificial confining potentials. A typical structure of this nature is the quantum dot, a nanoscale system which consists of few confined electrons. There are many types of quantum dots ranging from self-assembled to miniaturized semiconductor quantum dots. In this work we are interested in electrostatically confined semiconductor quantum dot systems where the electrostatic confining potential that traps the electrons is generated by external electrodes, doping, strain or other factors. A large number of semiconductor quantum dots of this type are fabricated by applying lithographically patterned gate electrodes or by etching on two-dimensional electron gases in semiconductor heterostructures. Because of this, the whole structure can be treated as a confined two-dimensional electron system. Quantum confinement profoundly affects the way in which electrons interact with each other, and external parameters such as a magnetic field. Since a magnetic field affects both the orbital and the spin motion of the electrons, the interplay between quantum confinement, electron-electron correlation effects and the magnetic field gives rise to very interesting physical phenomena. Thus, confined systems of electrons in a semiconductor quantum dot represent a unique opportunity to study fundamental quantum theories in a controllable atomic-like setup. In this work, we describe some common theoretical models which are used to study confined systems of electrons in a two-dimensional semiconductor quantum dot. The main emphasis of the work is to draw attention to important physical phenomena that arise in confined two-dimensional electron systems under various quantum regimes.

  13. A facile synthesis of 10-methoxy-4,8-dinitro-6H-benzothieno[2,3-c]chromen-6-one

    Directory of Open Access Journals (Sweden)

    SANDEEP BURUDKAR

    2004-07-01

    Full Text Available 3-Methoxy-5-nitrobenzaldehyde undergoes Knoevenagel reaction with malonic acid to give 3-methoxy-5-nitrocinnamic acid (I. Treatment of I with thionyl chloride yielded 3-chloro-5-methoxy-7-nitrobenzo[b]thiophene-2-carbonyl chloride (II in 45 % yield. The reaction of II with 2-nitrophenol in benzene gave 2-nitrophenyl 3-chloro-5-methoxy-7-nitrobenzo[b]thiophene-2-carboxylate (IIIa in 65 % yield. Finally, dehydrochlorinative photocyclization of IIIa in acetone in the presence of the base triethylamine afforded 10-methoxy-4,8-dinitro-6H-benzothieno[2,3-c]chromen-6-one (IVa. Thus, a series of derivatives IVa-i were synthesized in excellent yields. The structures of the obtained products were characterized by IR and 1H-NMR spectroscopy, as well as elemental analysis. Their purity was ascertained by chromatographic analysis. All the compounds were tested for their antibacterial activity against S. aureus, E. coli, B. subtilis and S. typhosa.

  14. One-dimensional Chain Topology in [Ag(C6H6NCl)2](ClO4),Generated through Weak Interaction between Molecules

    Institute of Scientific and Technical Information of China (English)

    孙道峰; 曹荣; 梁玉仓; 洪茂椿; 苏伟平

    2001-01-01

    The mononuclear complex [Ag(C6H6NC1)2](C1O4) has been prepared and structurally analyzed by single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group C2/c with unit cell parameters: a=15.5314(2), b=8.0247(8),c=15.3701 (2)A. β =118.832(2)°, V=1678.2(3)A3, Z=4, Mr=462.46, Dc=1.830Mg/m3, F(000)=912,μt (MoKa) = 1.694cm-1. The final R and wR are 0.0472 and 0.1272 for 1484 observed reflections with I≥3σ (Ⅰ). The Ag atom is coordinated by two nitrogen atoms of 4-chloromethyl-pyridine in a linear coordination geometry. Each molecule is further linked by the weak interaction between the C1 and Ag atoms to form a one-dimensional chain structure with Ag-C1 distance of 3.240(A).

  15. Crystal structures of Ca(ClO42·4H2O and Ca(ClO42·6H2O

    Directory of Open Access Journals (Sweden)

    Erik Hennings

    2014-12-01

    Full Text Available The title compounds, calcium perchlorate tetrahydrate and calcium perchlorate hexahydrate, were crystallized at low temperatures according to the solid–liquid phase diagram. The structure of the tetrahydrate consists of one Ca2+ cation eightfold coordinated in a square-antiprismatic fashion by four water molecules and four O atoms of four perchlorate tetrahedra, forming chains parallel to [01-1] by sharing corners of the ClO4 tetrahedra. The structure of the hexahydrate contains two different Ca2+ cations, each coordinated by six water molecules and two O atoms of two perchlorate tetrahedra, forming [Ca(H2O6(ClO4]2 dimers by sharing two ClO4 tetrahedra. The dimers are arranged in sheets parallel (001 and alternate with layers of non-coordinating ClO4 tetrahedra. O—H...O hydrogen bonds between the water molecules as donor and ClO4 tetrahedra and water molecules as acceptor groups lead to the formation of a three-dimensional network in the two structures. Ca(ClO42·6H2O was refined as a two-component inversion twin, with an approximate twin component ratio of 1:1 in each of the two structures.

  16. Synthesis and Crystal Structure of Potassium Triethylenetetraaminehexaacetatodi [Oxo- vanadium(Ⅳ)] Hexahydrate, K2[V2O2(ttha)]·6(H2O)

    Institute of Scientific and Technical Information of China (English)

    燕亚琪; 谢兆雄

    2003-01-01

    The title complex, potassium triethylenetetraaminehexaacetatodi [oxo-vanadium (Ⅳ)] hexahydrate K2[V2O2(ttha)](6(H2O), was synthesized in aqueous solution and its crystal structure has been determined by X-ray diffraction. The complex belongs to a triclinic system, space group Pī with a = 6.645(1), b = 9.870(2), c = 13.263(3)(A。), α = 70.68(3), β = 76.27(3), γ = 71.66(3)°, V = 770.5(3)(A。)3, Mr = 808.58, Dc = 1.743 g/cm3, Z = 1, μ = 0.968 mm-1, λ(MoKα) = 0.71073 (A。) and F(000) = 416. The final R = 0.0465 and wR = 0.1091 for 2974 observed diffractions with I ≥ 2σ(I). In the complex, the V atom is octahedrally coordinated to the oxo ligand, two N and three O atoms of the triethylenetetraaminehexaacetic (TTHA) ligand. All of the ten chelating sites are coordinated to the two vanadium atoms, and the coordination octahedron is distorted. Each [V2O2(ttha)]2- ion is further connected by the K+ ions through carboxyl groups of TTHA6- ion, forming a two dimensional network structure.

  17. Irradiation effects in 6H-SiC induced by neutron and heavy ions: Raman spectroscopy and high-resolution XRD analysis

    Science.gov (United States)

    Chen, Xiaofei; Zhou, Wei; Feng, Qijie; Zheng, Jian; Liu, Xiankun; Tang, Bin; Li, Jiangbo; Xue, Jianming; Peng, Shuming

    2016-09-01

    Irradiation effects of neutron and 3 MeV C+, Si+ in 6H-SiC were investigated by Raman spectroscopy and high-resolution XRD. The total disorder values of neutron irradiated SiC agree well with that of samples irradiated by ions at the same doses respectively. On the other hand, high-resolution XRD results shows that the lattice strain rate caused by neutron irradiation is 6.8%/dpa, while it is only 2.6%/dpa and 4.2%/dpa for Si+ and C+ irradiations respectively. Our results illustrate that the total disorder in neutron irradiated SiC can be accurately simulated by MeV Si+ or C+ irradiations at the same dose, but for the lattice strain and strain-related properties like surface hardness, the depth profile of irradiation damages induced by energetic ions must be considered. This research will contribute to a better understanding of the difference in irradiation effects between neutron and heavy ions.

  18. Synthesis and Crystal Structure of Cadmium(Ⅱ)Complex [Cd(H2O)(CH3OC6H4COO)2]n

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    At room temperature, the reaction of CdNO32@4H2O and anisic acid in an ethanol solution affords the cadmium (Ⅱ) complex [Cd(H2O)(CH3OC6H4COO)2]n. The crystal is of monoclinic, empirical formula C16H16O7Cd, Mr = 432.69, space group C2/c with parameters: a = 34.211(2), b = 6.030(2), c = 7.611(3)A, β = 95.619(5)°, V = 1562.5(9)A3, Z = 4, Dc = 1.831 g/cm3, μ = 1.434 mm-1, F000 = 856, R = 0.0215 and wR = 0.0456. 1121 reflections with I>2σ(I) were considered to be observed. Each cadmium atom is seven-coordinate in a distorted pentagonal bipyramidal geometry. The Cd (Ⅱ) center is doubly bridged with the neighboring Cd centers by anisate ligands to form a four-membered ring with a repeating unit of Cd-O-Cd-O-. The extended structure and hydrogen-bonding patterns displayed in the complex were studied.

  19. Synthesis and characterization of a new cyclohexaphosphate, (C6H7ClN)6P6O18·0.5(H2O)

    Science.gov (United States)

    Khedhiri, L.; Jeanneau, E.; Lefebvre, F.; Rzaigui, M.; Ben Nasr, C.

    2016-02-01

    A new cyclohexaphosphate with the composition (C6H7ClN)6P6O18·0.5(H2O) has been synthesized at room temperature in the presence of 4-chloroaniline as organic template and investigated by various physicochemical techniques. Its unit cell is triclinic P-1 with parameters a = 9.0054(8), b = 10.1053(9), c = 16.4454(14) Å, α = 100.476(7), β = 93.485(7), γ = 115.407(9) °, Z = 2 and V = 1313.0(2)Å3. The structure involves a network of inorganic parallel layers built up by P6O186 - ring anions, NH3 groups and water molecules. Charge balance is achieved by the protonated amine which is trapped in the interlayer space and interacts with the organic framework through strong hydrogen bonding. The 13C, 15N and 31P CP-MAS NMR spectra are in agreement with the X-ray structure. The vibrational absorption bands were identified by infrared spectroscopy. DFT calculations allowed the attribution of the NMR peaks.

  20. Oxidation-Induced Deep Levels in n - and p -Type 4 H - and 6 H -SiC and Their Influence on Carrier Lifetime

    Science.gov (United States)

    Booker, I. D.; Abdalla, H.; Hassan, J.; Karhu, R.; Lilja, L.; Janzén, E.; Sveinbjörnsson, E. Ö.

    2016-07-01

    We present a complete analysis of the electron- and hole-capture and -emission processes of the deep levels ON1, ON2a, and ON2b in 4 H -SiC and their 6 H -SiC counterparts OS1a and OS1b through OS3a and OS3b, which are produced by lifetime enhancement oxidation or implantation and annealing techniques. The modeling is based on a simultaneous numerical fitting of multiple high-resolution capacitance deep-level transient spectroscopy spectra measured with different filling-pulse lengths in n - and p -type material. All defects are found to be double-donor-type positive-U two-level defects with very small hole-capture cross sections, making them recombination centers of low efficiency, in accordance with minority-carrier-lifetime measurements. Their behavior as trapping and weak recombination centers, their large concentrations resulting from the lifetime enhancement oxidations, and their high thermal stability, however, make it advisable to minimize their presence in active regions of devices, for example, the base layer of bipolar junction transistors.

  1. Theoretical studies of the optical and EPR spectra for VO{sup 2+} in MgKPO{sub 4}·6H{sub 2}O single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hua-Ming, E-mail: huamingzhang66@gmail.com [Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang 330063 (China); Xiao, Wen-Bo [Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang 330063 (China); Wan, Xiong [Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang 330063 (China); Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics of the Chinese Academy of Sciences, Shanghai 200083 (China)

    2014-09-15

    The optical absorption and electron paramagnetic resonance (EPR) parameters (g factors g{sub ||}, g{sub ⊥} and hyperfine structure constants A{sub ||}, A{sub ⊥}) of a tetragonal V{sup 4+} center in MgKPO{sub 4}·6H{sub 2}O (MPPH) crystal are theoretically investigated using the perturbation formulas for a 3d{sup 1} ion in tetragonally compressed octahedra. In these formulas, the contributions from the s- and p-orbitals as well as the spin–orbit coupling coefficient of the O{sup 2−} ligand are taken into account based on the cluster approach. The calculated results are in good agreement with the observed values. The local structure parameters of the [VO{sub 6}]{sup 8−} cluster are obtained from the calculation. The magnitudes of the metal–ligand distances parallel and perpendicular to the C{sub 4}-axis are, respectively, R||≈1.846 Å and R{sub ⊥}≈2.032 Å. The validity of the calculated results has also been discussed. - Highlights: • The tetragonal field parameters are associated with the local structures of the impurity V{sup 4+} center. • Ligand contributions are taken into account from the cluster approach. • EPR and optical spectra are analyzed for the impurity V{sup 4+} center in the MPPH crystal.

  2. Synthesis and Crystal Structure of a 1-D Coordination Polymer {[Cu(NIT4py)2(ip)]·6H2O}n

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-Ping; GAO Dong-Zhao; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping; LI Li-Cun

    2006-01-01

    A new complex {[Cu(NIT4py)2(ip)]·6H2O}n (NIT4py=2-(4'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and ip = isophthalate dianion) has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in orthorhombic, space group Cmcm with a = 25.161(3), b =10.045(1), c = 15.450(2)(A), C32H48N6O14Cu, Mr = 804.30, V = 3904.8(8)(A)3, Z = 4, Dc = 1.368 g/cm3,μ(MoKα) = 0.630 mm-1, F(000) = 1692, the final R = 0.0326 and wR = 0.0787 for 1843 independent reflections with Rint = 0.0372. Each Cu(II) ion is four-coordinated by two carboxylate oxygen atoms and two pyridyl-N atoms from NIT4py radicals to furnish a rhombus geometry. The central Cu(II) ion is located at an inversion center and a crystallographic two-fold axis. Each isophthalate dianion binds two Cu(II) ions in bis-monodentate mode, leading to a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

  3. Onset of the alpha-relaxation in the glass-forming solution LiCl-6H2O revealed by Brillouin scattering techniques.

    Science.gov (United States)

    Santucci, S C; Comez, L; Scarponi, F; Monaco, G; Verbeni, R; Legrand, J-F; Masciovecchio, C; Gessini, A; Fioretto, D

    2009-10-21

    We measured the dynamic structure factor of the liquid and glassy phases of the LiCl-6H(2)O solution by means of inelastic scattering of radiation in the visible, UV, and x-ray range, between 1 GHz and 10 THz, and by means of photon-correlation spectroscopy, between 0.01 Hz and 20 kHz. The measurements were performed in the temperature range between 353 and 80 K. Our data show that a single-relaxation process exists at high temperature, which has features similar to those of the single relaxation of pure water. Upon cooling the system below approximately 220 K, this single mode starts to differentiate two processes, a structural (alpha-) and a secondary (beta-) relaxation. As the temperature is decreased, the beta-relaxation is the vanishing continuation of the single, high-temperature process, while the onset of the alpha-relaxation occurs at the expense of the beta-process. PMID:20568872

  4. cAMP dependent and independent regulation of thyroglobulin synthesis by two clones of the OVNIS 6H thyroid cell line.

    Science.gov (United States)

    Aouani, A; Hovsépian, S; Fayet, G

    1987-07-01

    The hormonal regulation of thyroglobulin synthesis has been studied using two independent clones of the OVNIS 6H cell line. Insulin, hydrocortisone and TSH were able to stimulate thyroglobulin synthesis, whereas transferrin, somatostatin and glycyl-histidyl-lysine were without effect. Insulin stimulated thyroglobulin synthesis without affecting cAMP production. Hydrocortisone, when combined with insulin was a stimulator too; this stimulation was not accompanied by an increase in cAMP. TSH alone was unable to stimulate either cAMP or thyroglobulin synthesis. The stimulatory effect of TSH on thyroglobulin synthesis took place only when combined with insulin or insulin plus hydrocortisone, and was mediated by cAMP. Consequently, insulin and hydrocortisone stimulated thyroglobulin synthesis by cAMP-independent mechanisms, whereas TSH acted via the cAMP system. Forskolin mimicked TSH effects on cAMP and thyroglobulin synthesis. Calf serum inhibited cAMP and thyroglobulin production. Optimal cAMP and thyroglobulin synthesis as well as TSH responsiveness were obtained in serum-free medium supplemented with 5 micrograms/ml insulin, 100 nM hydrocortisone and 1 mU/ml TSH. PMID:3040495

  5. Syntheses, characterization, and luminescence of two lanthanide complexes [Ln2(acetate)6(H2O)4]·4H2O (Ln=Tb(1), Sm(2))

    Institute of Scientific and Technical Information of China (English)

    YU Qiongyan; ZHOU Xiuxia; LIU Maosheng; CHEN Jianqiao; ZHOU Zhengyuan; YIN Xia; CAI Yuepeng

    2008-01-01

    Two dinuclear compounds [Ln2(acetate)6(H2O)4]·4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P(-1). The coordination geometry around Ln(III) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(III) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.

  6. Effects of unstratified and centre-stratified randomization in multi-centre clinical trials.

    Science.gov (United States)

    Anisimov, Vladimir V

    2011-01-01

    This paper deals with the analysis of randomization effects in multi-centre clinical trials. The two randomization schemes most often used in clinical trials are considered: unstratified and centre-stratified block-permuted randomization. The prediction of the number of patients randomized to different treatment arms in different regions during the recruitment period accounting for the stochastic nature of the recruitment and effects of multiple centres is investigated. A new analytic approach using a Poisson-gamma patient recruitment model (patients arrive at different centres according to Poisson processes with rates sampled from a gamma distributed population) and its further extensions is proposed. Closed-form expressions for corresponding distributions of the predicted number of the patients randomized in different regions are derived. In the case of two treatments, the properties of the total imbalance in the number of patients on treatment arms caused by using centre-stratified randomization are investigated and for a large number of centres a normal approximation of imbalance is proved. The impact of imbalance on the power of the study is considered. It is shown that the loss of statistical power is practically negligible and can be compensated by a minor increase in sample size. The influence of patient dropout is also investigated. The impact of randomization on predicted drug supply overage is discussed.

  7. It's all change at the Computer Centre

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    The IT and EN Departments are modernising the infrastructure of the Computer Centre to improve the conditions in which the equipment has to operate and to increase capacity. The construction work has already begun and is due to be completed in October 2012.   Every year CERN experiences around ten power cuts lasting from less than a second to several hours. In most cases the two protection systems - the UPS* and the diesel generators – are able to ensure that the operation of the Computer Centre is not affected. As Vincent Doré, the project leader for the IT Department, and Paul Pepinster, the EN Department's technical coordinator in charge of modernising the infrastructure, explains: "Building 513 has two types of computing facilities – the "non-critical" ones, such as the servers for "off-line" computing, which have UPS systems ensuring that they can operate for 10 minutes after a power cut, and the "critical&...

  8. JOB CENTRE FOR DOMESTIC STAFF IN SWITZERLAND

    CERN Multimedia

    Relations with the Host States Service; http://www.cern.ch/relations/

    2001-01-01

    The Permanent mission of Switzerland to the International Organisations in Geneva has informed CERN that the Geneva Welcome Centre has set up an employment registration desk for the domestic staff of international civil servants. The aim of this pilot project is, on the one hand, to help international civil servants find domestic staff and, on the other hand, to help domestic staff holding an 'F'-type carte de légitimation find employment within 30 days after the expiry of a contract. For more information, please contact the Geneva Welcome Centre, La Pastorale, 106, route de Ferney, Case postale 103, 1211 Genève 20, tel. (+41.22) 918 02 70, fax (+41.22) 918 02 79), http://geneva-international.org/Welcome.E.html.

  9. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    A significant factor in the decrease of sensitivity to low-frequency sound is the helicotrema shunt effect. In humans, it causes a slope increase of the middle-ear transfer function (METF) from 6 dB/oct to 12 dB/oct below approximately 50 Hz [Marquardt et al., J.Acoust. Soc. Am. 121, 3628...... measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences......-3638 (2007)]. Recent experiments showed that the exact frequency varies from individual to individual. Besides, the helicotrema region in the METF has been found to highly influence frequency selectivity for centre frequencies (CFs) below 80 Hz (Jurado and Moore in prep). By using individual METF...

  10. Patient-centred Prevention among PAD Patients

    DEFF Research Database (Denmark)

    Pii, Kathrine Hoffmann

    2014-01-01

    that will improve their health condition. The patient-centred approach (and related concepts: patient participation, involvement, and empowerment) is being promoted both in healthcare politics and by healthcare professionals as a way to achieve more active self-managing and self-caring patients. Patient......-centredness is thus promoted as a way to organize health more effectively (in terms of cost and treatment outcomes) and as a way to ensure patients’ autonomy and fundamental right to make their own decisions regarding their treatment. Critical voices within social and nursing theory have however argued...... that the patient-centred approach does not ensure patient autonomy, but continues to be organized according to biomedical regimes and thereby carry on a paternalistic approach. In this paper, I present findings from a PhD project, which investigates how the ideal of patient-centredness is practiced in the case...

  11. Danish Polymer Centre annual report 2001

    DEFF Research Database (Denmark)

    Hassager, O.; Hvilsted, S.; Mortensen, Kell

    The centre is a collaboration between the Risø National Laboratory and the Technical University of Denmark (DTU). At the DTU the Department of Chemical Engineering and the Department of Manufacturing Engineering and Management participate in the centre.From 2001 the Polymer Department at Risø...... coordinates the activities at Risø From the outset it was considered important with common laboratories to obtain the full effect of the collaboration between the two departments at the DTU and Risø NationalLaboratory. In 2001 new laboratories for polymer research and education were established at the DTU...... campus in Lyngby as shown in the pictures on this page. In addition to well equipped laboratories at Risø which will be expanded in 2002 and 2003, thesefacilities provide a common ground for polymer chemists, polymer physicists, chemical engineers and mechanical engineers from the two institutions...

  12. Display-centred applications in ubiquitous computing

    OpenAIRE

    José, Rui; Pinto, Helder

    2006-01-01

    Public displays can play an important enabling role in ubiquitous computing environments. This paper describes an on-going work for a multipurpose, multi-display infrastructure, designed to address the requirements of display-centred applications in ubiquitous computing environments. The system provides an infrastructure in which situated displays can act as portals to the physical space, allowing ubicomp applications to support their association with the physical world by providing them with...

  13. The Researcher : The Refugee Documentation Centre Newsletter

    OpenAIRE

    Ahmed, Elisabeth; Goggins, David

    2014-01-01

    Contents: Subsidiary Protection – a distinct and autonomous form of complementary protection / Enda O’Neill, Jennifer Higgins, UNHCR Ireland; Recent Changes at the Refugee Appeals Tribunal / Barry Magee, Refugee Appeals Tribunal; The Use of Decision Templates for Refugee Status Determination / Seán O’Connell, Refugee Appeals Tribunal; Forced Marriage in Afghanistan / David Goggins, Refugee Documentation Centre; Houses of the Holy: Iraq and the last days of the Mandeans / Patrick Dowling, R...

  14. Structure and Responsibilities of Radiation Protection Centre

    International Nuclear Information System (INIS)

    Constitution of Radiation Protection Centre (RPC) in Lithuania is presented. RPC was established in 1997, in 1999 the Government granted the status of the regulatory authority of Lithuania on radiation protection issues. Currently there are two departments at RPC: two in Vilnius - Department of Radiation Protection Supervision and Control and Department of Programs and Expertise, and four in the districts. Main tasks of RPC are listed

  15. Imperial College Reactor Centre annual report. 1983

    International Nuclear Information System (INIS)

    It is reported that the reactor operated reliably during the year with less than half a day of operating time lost by faults or failures. Brief accounts of the 34 research projects at the Centre are given, and a list of teaching experiments or visits is included. These include undergraduate and post-graduate teaching. Commercial requests for irradiations and neutron activation analysis are reported as increasing. (U.K.)

  16. CMS Centres Worldwide - a New Collaborative Infrastructure

    CERN Document Server

    Taylor, Lucas

    2011-01-01

    Webcasts, and generic Web tools such as CMS-TV for broadcasting live monitoring and outreach information. Being Web-based and experiment-independent, these systems could easily be extended to other organizations. We describe the experiences of using CMS Centres Worldwide in the CMS data-taking operations as well as for major media events with several hundred TV channels, radio stations, and many more press journalists simultaneously around the world.

  17. Learning Styles of Independent Learning Centre Users

    OpenAIRE

    Tarik Uzun

    2014-01-01

    Learning style research has been a significant field within language teaching and learning. There have been very few attempts, however, to seek possible links between independent learning and learning style preferences. This paper aims to identify the learning styles of students who use the Independent Learning Centre (ILC) on a regular basis at a state university in Turkey (n=102). The findings of the learning style analysis revealed that, contrary to expectations, most of the regular users ...

  18. LSE centre for economic performance: bankers’ bonuses

    OpenAIRE

    Bell, Brian

    2010-01-01

    A new series of Election Analyses is now available from the LSE’s Centre for Economic Performance (CEP). The series will discuss the research evidence on some of the key policy battlegrounds of the 2010 General Election, including macroeconomic policy, immigration, health, education, crime, poverty and inequality, labour market policy, regional policy, energy and the environment, financial regulation and bankers’ bonuses, and foreign aid. The latest CEP Election Analysis, by Brian Bell, g...

  19. Enhancing Safety at Airline Operations Control Centre

    Directory of Open Access Journals (Sweden)

    Lukáš Řasa

    2015-04-01

    Full Text Available In recent years a new term of Safety Management System (SMS has been introduced into aviation legislation. This system is being adopted by airline operators. One of the groundbased actors of everyday operations is Operations Control Centre (OCC. The goal of this article has been to identify and assess risks and dangers which occur at OCC and create a template for OCC implementation into SMS.

  20. The LifeWatch Service Centre Plan

    OpenAIRE

    Parr, Terry; Spinelli, Oliviero; Mauri, Maria Paola; Billisari, Livia; Hardisty, Alex; Ludlow, David; Khan, Zaheer; Roberts, Dave; Sleep, Chris; Sier, Andrew

    2011-01-01

    This report summarises the construction plan for the Lifewatch Service Centre. The main purpose of LifeWatch is to serve the biodiversity and ecosystem research community in its work on the understanding and rational management of our ecosystems for use by policy makers, resource managers, the private sector and the general public. To do this the LifeWatch infrastructure will provide capabilities to analyse, model and simulate with integrated biodiversity and ecosystem data from many dive...

  1. User-Centred Design Using Gamestorming.

    Science.gov (United States)

    Currie, Leanne

    2016-01-01

    User-centered design (UX) is becoming a standard in software engineering and has tremendous potential in healthcare. The purpose of this tutorial will be to demonstrate and provide participants with practice in user-centred design methods that involve 'Gamestorming', a form of brainstorming where 'the rules of life are temporarily suspended'. Participants will learn and apply gamestorming methods including persona development via empathy mapping and methods to translate artefacts derived from participatory design sessions into functional and design requirements.

  2. Training science centre Explainers. The Techniquest experience

    Directory of Open Access Journals (Sweden)

    Colin Johnson

    2005-12-01

    Full Text Available Techniquest was established in 1986, and in 1995 moved to its current premises at Cardiff Bay, South Wales. This was the first purpose-built science centre in the UK. It receives around 200,000 visitors every year to its exhibition, and to its programmes for schools and public audiences in the theatre, laboratory, discovery room and planetarium. The author joined the Techniquest project in 1985, became a staff member in 1990 and was the Chief Executive from 1997 until his retirement in 2004. Techniquest has three “out-stations” in Wales, and is responsible for the supply and maintenance of exhibits to the Look Out Discovery Centre in Bracknell, England. There is a Techniquest gallery at the Lisbon Pavilhão do Conhecimento - Ciência Viva, and a traveling exhibition, SciQuest, in South Africa which was also supplied by Techniquest. All these centres rely on the effective intervention of “Explainers” (at Techniquest we call them “Helpers” to provide the best possible experience for visitors. At its most demanding, the tasks of an Explainer are varied and intensive, yet there may be times when the duties are mundane or even dull. When you rely on people to act as both hosts and housekeepers, to provide both support and stimulus, and to be both welcoming and watchful, you are asking a great deal. This article raises some of the issues concerned with the recruitment and retention of Explainers, their training and management, and the way in which their role is recognized and valued by the science centre as a whole.

  3. INFOTERM – Information Disseminating Centre for Terminology

    Directory of Open Access Journals (Sweden)

    Albina Auksoriūtė

    2014-12-01

    Full Text Available International Information Centre for Terminology (INFOTERM was founded in 1971 by contract with the United Nations Educational, Scientific and Cultural Organization (UNESCO and the Austrian Standards Institute (ASI. In 1996, INFOTERM was reorganized and established as an independent non-profit organization. INFOTERM promotes and supports the cooperation of existing and the establishment of new terminology centres and networks with the general aim to improve domain communication, knowledge transfer and provision of content with view to facilitating the participation of all in the global multilingual knowledge society. The article presents not only a history of the foundation of INFOTERM, the tasks and activities of INFOTERM and its members, which are international, regional or national terminology institutions, organizations and networks, as well as specialized public or semi-public or other non-profit institutions engaged in terminological activities, but also analyses “Guidelines for terminology policies”, preparied by INFOTERM, and cooperation between INFOTERM and the Institute of the Lithuanian Language.In conclusion, the experience and sharing expertise of INFOTERM regarding harmonized methods and guidelines for terminology management and policies, the management of terminology centres, terminology standardization, the use of terminological data, methods and tools in all applications etc are very important for all countries and language communities especially for countries and language communities with less mature terminologies. The Institute of the Lithuanian Language as a member of INFOTERM has a possibility to get information on terminology research and training, terminology publications, terminological events and activities all over the world.

  4. Upcoming opening of CERN's new Mobility Centre

    CERN Multimedia

    2016-01-01

    On 29 February, CERN’s brand new Mobility Centre opened in the Globe car park. The Centre has been created to cater to the transport needs of everyone at CERN, to simplify procedures and to centralise all the transport services on offer: the rental of CERN bikes and cars, the CERN car-sharing scheme and SIXT car rental.   From 29 February onwards, the Mobility Centre in the Globe car park will be the place to go for all your duty travel needs: rental of CERN cars (with or without the CERN logo), SIXT car rental, CERN bike rental, distribution of cards allowing the use of CERN’s self-service bike- and car-sharing schemes. That same day, the premises currently housing the Car Pool in Building 130 will become the CERN garage, responsible for: upkeep and repairs on CERN bikes, minor maintenance work on CERN vehicles (e.g. replacing windscreen wipers, bulbs and fuses, refilling windscreen washer fluid, pumping up tyres, etc.), arranging and following up the repair and maintenan...

  5. A new visitor centre for CMS

    CERN Multimedia

    2001-01-01

    At the inauguration of the new CMS visitor centre. The CMS experiment inaugurated a new visitor centre at its Cessy site on 14 June. This will allow the thousands of people who come to CERN each year to follow the construction of one the Laboratory's flagship experiments first-hand. CERN receives over 20,000 visitors each year. Until recently, many of them were taken on a guided tour of one of the LEP experiments. With the closure of LEP, however, trips underground are no longer possible, and the Visits' Service has put in place a number of other itineraries (Bulletin 46/2000). Since the CMS detector will be almost entirely constructed in a surface hall, it is now taking a big share of the limelight. The CMS visitor centre has been built on a platform overlooking CMS construction. It contains a set of clear descriptive posters describing the experiment, along with a video projection showing animations and movies about CMS construction. In the coming weeks, a display of CMS detector elements will be added, as...

  6. Gamma Rays frim the Galactic Centre

    CERN Document Server

    Erlykin, A D

    2007-01-01

    Recent results from the HESS gamma ray telescope have shown the presence of both a diffuse, extended, flux of gamma rays above ~0.4 TeV and discrete sources in and near the Galactic Centre. Here, we put forward a possible explanation in terms of the diffusion of cosmic ray protons from a succession of supernova remnants (SNR) in the SgrA* region of the Galaxy plus a contribution from SNR in the rest of the Galactic Centre Region, to be called the Galactic Centre Ridge (GCR). Protons are favoured over electrons because the mG magnetic fields in the Region will attenuate energetic electrons severely. Prominent features are the need for 'anomalous diffusion' of the protons in the whole region and the adoption of low efficiency for SNR acceleration in the high density regions. The latter is related by us to the well-known low 'cosmic ray gradient' in the Galaxy. A corroborating feature is the close correlation of inferred cosmic ray intensity with the smoothed intensity of 5 GHZ radio radiation. We attribute this...

  7. Colloidal Quantum dot photovoltaics: Tuning optoelectronic properties

    International Nuclear Information System (INIS)

    Full text: Colloidal quantum dots combine processing from the solution phase with tunability of the bandgap. Via the size-effect the optical properties can be matched to the solar spectrum for a wide-range photon harvesting. To engineer photovoltaic devices, quantum dots are compressed from their colloidal form into a close-packed nanocrystal matrix, while undergoing a systematic layer-by-layer process. The resulting quantum dot solid is treated as semiconductor medium - one having electron-hole mobilites, free carrier densities and a dielectric constant. While the size-effect determined the band-gap before, it is now the nature of ligand and the treatment route, that influences mentioned electronic parameters. We took the view on the processing steps and found a concept for analysing trap states, moblility and device performance in real quantum dot solids. Our findings emphasize the interplay of mobility and trap-distribution with routes that take special care on the nanocrystal surface and hence conserve optoelectronic qualities of quantum dots for efficient photovoltaic cells. (author)

  8. Photoluminescence of carbon dots from mesoporous silica

    Science.gov (United States)

    Nelson, D. K.; Razbirin, B. S.; Starukhin, A. N.; Eurov, D. A.; Kurdyukov, D. A.; Stovpiaga, E. Yu; Golubev, V. G.

    2016-09-01

    Photophysical properties of carbon dots were investigated under various excitation conditions and over a wide temperature region - from room to liquid helium temperatures. The carbon dots (CDs) were synthesized using mesoporous silica particles as a reactor and (3-aminopropyl)triethoxysilane (APTES) as a precursor. The photoluminescence spectra of CDs exhibit a strong dependence on the excitation wavelength and demonstrate a significant inhomogeneous broadening. Lowering sample temperature reveals the doublet structure of the spectra, which is associated with the vibronic structure of radiative transitions. The vibration energy ∼1200 cm-1 is close to the energy of Csbnd O stretching vibration. Long-lived phosphorescence of carbon dots with its decay time ∼0.2 s at T = 80 K was observed. The fluorescence and phosphorescence spectra are shown to be spectrally separated. The long-lived component of the emission was ascribed to optically forbidden triplet-singlet transitions. The value of the singlet-triplet splitting was found to be about 0.3 eV. Photo-induced polarization of the luminescence of carbon dots was revealed. The degree of the linear polarization is dependent on the wavelengths of both excitation and emitted light. The effect indicates a hidden anisotropy of optical dipole transitions in the dots and demonstrates the loss of the dipole orientation during the electron energy relaxation.

  9. In-vitro and in-vivo evaluation of the anticancer activity of diruthenium-2, a new trithiolato arene ruthenium complex [(η6-p-MeC6H4Pri)2Ru2(μ-S-p-C6H4OH)3]Cl.

    Science.gov (United States)

    Muthná, Darina; Tomšík, Pavel; Havelek, Radim; Köhlerová, Renata; Kasilingam, Vidhya; Čermáková, Eva; Stíbal, David; Řezáčová, Martina; Süss-Fink, Georg

    2016-08-01

    In the present study, we investigated the anticancer action of the trithiolato arene ruthenium complex, [(η-p-MeC6H4Pr)2Ru2(μ-S-p-C6H4OH)3]Cl, named diruthenium-2, both in vitro and in vivo. The mechanism of antiproliferative, cytotoxic, and DNA-damaging activity, and the effect on expressions of cell cycle regulatory proteins were investigated using a WST-1-based proliferation assay, lactate dehydrogenase leakage assay, comet assay, flow cytometry, and western blot analysis. In-vivo anticancer activity was evaluated using Ehrlich tumor-bearing NMRI mice. Diruthenium-2 inhibited the growth of all cancer cell lines used, the most sensitive being gastric (AGS), breast cancer (BT-549, MCF-7, MDA-MB-231), and leukemic (HL-60, MOLT-4) cells. In MCF-7 cells, it caused a G1/S cell cycle arrest, along with an increase in the expression of protein p21 and cyclin B1. We also observed increased levels of MRN complex proteins, which, together with the results from the comet assay, indicate the formation of DNA double-strand breaks. In tumor-bearing mice, diruthenium-2 at doses of 3 and 5 mg/kg inhibits the growth of solid Ehrlich tumor, although weaker than cisplatin. However, it did not prolong the post-therapeutic survival. Our results suggest the in-vitro potential of diruthenium-2 should be further evaluated in studies using other in-vivo models. PMID:27187018

  10. 总剂量辐照SiO2/6H-SiC引起的界面势垒变化%Total Dose Radiation Induced Interface Barriers Changing of SiO2/6H-SiC Structure

    Institute of Scientific and Technical Information of China (English)

    牟维兵; 龚敏; 曹群

    2011-01-01

    辐照会引起MOS器件电介质氧化物与半导体界面势垒变化,影响其工作性能和可靠性.测量了n型6H-SiC MOS电容辐照105rad(Si)剂量前后的Ⅰ-Ⅴ线,通过Fowler-Nordheim(F-N)隧道电流拟合,得到了界面势垒的大小,辐照前的为2.596 eV,辐照后降为1.492eV.界面势垒变化主要是由辐照产生的界面态引起的.%The barrier between oxide and SiC interface would change due to irradiation.And operating characteristics would be affected. I-V curves of n-type 6H-SiC MOS capacitor before and after 105rad(Si) irradiation are measured. Interface barriers are calculated by FowlerNordheim tunneling fit. The barrier before irradiation is 2. 446 eV, and that is 1. 604 eV after irradiation. Shift of barrier is main due to acceptor type interface states produced by irradiation.

  11. Inorganic passivation and doping control in colloidal quantum dot photovoltaics

    KAUST Repository

    Hoogland, Sjoerd H.

    2012-01-01

    We discuss strategies to reduce midgap trap state densities in colloidal quantum dot films and requirements to control doping type and magnitude. We demonstrate that these improvements result in colloidal quantum dot solar cells with certified 7.0% efficiency.

  12. Nanosized Carbon Dots from Organic Matter and Biomass

    Institute of Scientific and Technical Information of China (English)

    LI Yuanyuan; CHEN Tong; MA Yulong

    2016-01-01

    Carbon nanoparticles (C-dots) were prepared by relfuxing the combustion soots of candles and corn stalk in nitric acid. The synthesized C-dots were characterized. The results showed a sharp increase in oxygen content and a sharp decrease in carbon content after oxidation. The C-dots had -OH and -CO2H groups introduced which made them hydrophilic. However, their difference was also obvious. The C-dots from candle soot had a 10-45 nm broad particle size distribution, and those from corn stalk soot had a 6-18 nm relatively small and narrow size distribution. The C-dots were mainly ofsp2 andsp3 carbon structure different from the C-dots of diamond-like structure from candle soot. Interestingly, two kinds of C-dots all exhibited unique photoluminescent properties. The obtained C-dots have potential applications in a broad range of areas.

  13. Origins and optimization of entanglement in plasmonically coupled quantum dots

    Science.gov (United States)

    Otten, Matthew; Larson, Jeffrey; Min, Misun; Wild, Stefan M.; Pelton, Matthew; Gray, Stephen K.

    2016-08-01

    A system of two or more quantum dots interacting with a dissipative plasmonic nanostructure is investigated in detail by using a cavity quantum electrodynamics approach with a model Hamiltonian. We focus on determining and understanding system configurations that generate multiple bipartite quantum entanglements between the occupation states of the quantum dots. These configurations include allowing for the quantum dots to be asymmetrically coupled to the plasmonic system. Analytical solution of a simplified limit for an arbitrary number of quantum dots and numerical simulations and optimization for the two- and three-dot cases are used to develop guidelines for maximizing the bipartite entanglements. For any number of quantum dots, we show that through simple starting states and parameter guidelines, one quantum dot can be made to share a strong amount of bipartite entanglement with all other quantum dots in the system, while entangling all other pairs to a lesser degree.

  14. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  15. Addressing the challenges of patient-centred design

    Directory of Open Access Journals (Sweden)

    Karen LaBat

    2009-11-01

    Full Text Available Patient-centred design is a relatively new term, but a longstanding concept in clinical practice. This discussion looks at patient-centred design and explores the relationships of patient-centred design to universal design, user-centred design and the newer human-centred design. It also explores why interdisciplinary approaches are needed for patient-centred design and how interdisciplinary collaboration works to address the challenges of patient centred design. Successful patient-centred solutions can grow from collaborations which include shared visions, understanding of both the nature and degree of variation in the patient,materials, and the designed solution, clear regular communication among all parties with careful definition of terms, and respect for the inherent cultures of all disciplines involved.

  16. Isomer-selective detection of microsolvated oxonium and carbenium ions of protonated phenol: Infrared spectra of C6H7O+-Ln clusters (L=Ar/N2, n≤6)

    International Nuclear Information System (INIS)

    Infrared photodissociation (IRPD) spectra of clusters composed of protonated phenol (C6H7O+) and several ligands L are recorded in the O-H and C-H stretch ranges using a tandem mass spectrometer coupled to a cluster ion source. The C6H7O+-Ln complexes (L=Ar/N2, n=1-6) are generated by chemical ionization of a supersonic expansion. The IRPD spectra of mass selected C6H7O+-Ln clusters obtained in various C6H7O+-Lm fragment channels (m6H7O+ nucleation centers: the oxonium ion (5) and the carbenium ion(s) corresponding to protonation of phenol in ortho and/or para position (1/3). These two classes of C6H7O+-Ln isomers show very different fragmentation behavior upon IR excitation, facilitating the assignment of the observed vibrational transitions. The vibrational frequency shifts as a function of cluster size reveal that the microsolvation of 1/3 and 5 in Ar and N2 begins with the formation of intermolecular hydrogen bond(s) to the acidic OH group(s) and proceeds by the formation of intermolecular π-bonds to the respective six-membered rings. The analysis of photofragmentation branching ratios yields estimated ligand binding energies of the intermolecular OH- and π-bonds for solvation of the different C6H7O+ isomers. The effects of microsolvation on the properties of 1/3 as reactive intermediates in electrophilic aromatic substitution reactions are discussed. Comparison of clusters of protonated phenol with those of neutral phenol reveals the drastic protonation-induced changes in the topology of the intermolecular potential of aromatic molecules interacting with a nonpolar solvent. Moreover, the results show that the IRPD process can be used to selectively generate a spectroscopically clean ion beam of either 1/3 or 5 with some control over their internal energies

  17. The three-level ripples induced by femtosecond laser on a 6H-SiC single crystal and the formation mechanism

    Science.gov (United States)

    Song, Juan; Tao, Wenjun; Gong, Min; Ye, Junyi; Dai, Ye; Ma, Guohong; Qiu, Jianrong

    2016-04-01

    In this paper, a line-scanning irradiation of 6H-SiC single crystal by a femtosecond laser focus was implemented for laser fluence of 2.2 J/cm2 at different scanning velocities from 1000 down to 100 μm/s. The morphology of the obtained ablation lines characterized by a scanning electron microscope shows that there progressively appear three-level ripples with average period of about 222, 600 nm and that between them. Possible formation mechanisms for these three-level ripples were analyzed by numerical simulation employing finite-difference time-domain method (FDTD). Analysis shows that as Obara proposed, the interference of incident wave with the wave scattered by scratches possibly left by fine polishing is the most possible reason for inducing 222 nm-period and 600 nm-period ripples. Main discussions were focused on the orientation characteristics of ripples. Both isolated scratches and crossed scratches with different orientation angles were considered for evaluating their role in field redistribution. The detailed simulations indicate that for scratches oriented 90° with respect to laser polarization generate a pair of strongest ripple-like optical field enhancement compared to scratches with other orientation angles. It is these advantages of 90°-oriented scratch in field enhancement that make the final ripple perpendicular to laser polarization most competitive and finally left on the surface. This complements the physical picture of Obara et al. in terms of their negligence in addressing the orientation characteristics of ripples. Further FDTD simulation of the interaction of incident wave with as-formed 600 nm-period ripples shows that the optical field enhancement located between any two adjacent 600 nm-period ripples is the driving force for splitting 600 nm-period ripples into the third ripples with period between 222 and 600 nm.

  18. Probability density fittings of corrosion test-data: Implications on C6H15NO3 effectiveness on concrete steel-rebar corrosion

    Indian Academy of Sciences (India)

    Joshua Olusegun Okeniyi; Idemudia Joshua Ambrose; Stanley Okechukwu Okpala; Oluwafemi Michael Omoniyi; Isaac Oluwaseun Oladele; Cleophas Akintoye Loto; Patricia Abimbola Idowu Popoola

    2014-06-01

    In this study, corrosion test-data of steel-rebar in concrete were subjected to the fittings of the Normal, Gumbel and the Weibull probability distribution functions. This was done to investigate the suitability of the results of the fitted test-data, by these distributions, for modelling the effectiveness of C6H15NO3, triethanolamine (TEA), admixtures on the corrosion of steel-rebar in concrete in NaCl and in H2SO4 test-media. For this, six different concentrations of TEA were admixed in replicates of steel-reinforced concrete samples which were immersed in the saline/marine and the microbial/industrial simulating test-environments for seventy-five days. From these, distribution fittings of the non-destructive electrochemical measurements were subjected to the Kolmogorov–Smirnov goodness-of-fit statistics and to the analyses of variance modelling for studying test-data compatibility to the fittings and testing significance. Although all fittings of test-data followed similar trends of significant testing, the fittings of the corrosion rate test data followed the Weibull more than the Normal and the Gumbel distribution fittings, thus supporting use of the Weibull fittings for modelling effectiveness. The effectiveness models on rebar corrosion, based on these, identified 0.083% TEA with optimal inhibition efficiency, $\\eta =$ 72.17 ± 10.68%, in NaCl medium while 0.667% TEA was the only admixture with positive effectiveness, $\\eta =$ 56.45±15.85%, in H2SO4 medium. These results bear implications on the concentrations of TEA for effective corrosion protection of concrete steel-rebar in saline/marine and in industrial/microbial environments.

  19. Study of Defect Structures in 6H-SiC a/ m-Plane Pseudofiber Crystals Grown by Hot-Wall CVD Epitaxy

    Science.gov (United States)

    Goue, Ouloide Y.; Raghothamachar, Balaji; Yang, Yu; Guo, Jianqiu; Dudley, Michael; Kisslinger, Kim; Trunek, Andrew J.; Neudeck, Philip G.; Spry, David J.; Woodworth, Andrew A.

    2016-04-01

    Structural perfection of silicon carbide (SiC) single crystals is essential to achieve high-performance power devices. A new bulk growth process for SiC proposed by researchers at NASA Glenn Research Center, called large tapered crystal (LTC) growth, based on axial fiber growth followed by lateral expansion, could produce SiC boules with potentially as few as one threading screw dislocation per wafer. In this study, the lateral expansion aspect of LTC growth is addressed through analysis of lateral growth of 6H-SiC a/ m-plane seed crystals by hot-wall chemical vapor deposition. Preliminary synchrotron white-beam x-ray topography (SWBXT) indicates that the as-grown boules match the polytype structure of the underlying seed and have a faceted hexagonal morphology with a strain-free surface marked by steps. SWBXT Laue diffraction patterns of transverse and axial slices of the boules reveal streaks suggesting the existence of stacking faults/polytypes, and this is confirmed by micro-Raman spectroscopy. Transmission x-ray topography of both transverse and axial slices reveals inhomogeneous strains at the seed-epilayer interface and linear features propagating from the seed along the growth direction. Micro-Raman mapping of an axial slice reveals that the seed contains high stacking disorder, while contrast extinction analysis (g· b and g· b× l) of the linear features reveals that these are mostly edge-type basal plane dislocations. Further high-resolution transmission electron microscopy investigation of the seed-homoepilayer interface also reveals nanobands of different SiC polytypes. A model for their formation mechanism is proposed. Finally, the implication of these results for improving the LTC growth process is addressed.

  20. Coherence and dephasing in self-assembled quantum dots

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Leosson, K.; Birkedal, Dan

    2003-01-01

    We measured dephasing times in InGaAl/As self-assembled quantum dots at low temperature using degenerate four-wave mixing. At 0K, the coherence time of the quantum dots is lifetime limited, whereas at finite temperatures pure dephasing by exciton-phonon interactions governs the quantum dot...... coherence. The inferred homogeneous line widths are significantly smaller than the line widths usually observed in the photoluminescence from single quantum dots indicating an additional inhomogeneours broadening mechanism in the latter....

  1. Short-wave infrared colloidal quantum dot photodetectors on silicon

    OpenAIRE

    Hu, Chen; Gassenq, Alban; Justo, Yolanda; Yakunin, Sergii; Heiss, Wolfgang; Hens, Zeger; Roelkens, Gunther

    2013-01-01

    In this paper, two kinds of colloidal quantum dots, PbS and HgTe, are explored for SWIR photodetectors application. The colloidal dots are prepared by hot injection chemical synthesis, with organic ligands around the dots keeping them stable in solution. For the purpose of achieving efficient carrier transport between the dots in a film, these long organic ligands are replaced by shorter, inorganic ligands. We report uniform, ultra-smooth colloidal QD films without cracks realized by dip-coat...

  2. Quantum Dots in Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Sollner, Immo Nathanael

    This Thesis is focused on the study of quantum electrodynamics in photonic crystal waveguides. We investigate the interplay between a single quantum dot and the fundamental mode of the photonic crystal waveguide. We demonstrate experimental coupling eciencies for the spontaneous emission...... into the mode exceeding 98% for emitters spectrally close to the band-edge of the waveguide mode. In addition we illustrate the broadband nature of the underlying eects, by obtaining coupling eciencies above 90% for quantum dots detuned from the band edge by as far as 20nm. These values are in good agreement...... quantum-dot-waveguide coupling. Such a structure is ideally suited for a number of applications in quantum information processing and among others we propose an on-chip spin-photon interface, a single photon transistor, and a deterministic cNOT gate....

  3. Charged-Exciton Complexes in Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang

    2001-01-01

    It is known experimentally that stable charged-exciton complexes can exist in low-dimensional semiconductor nanostructures. Much less is known about the properties of such charged-exciton complexes since three-body problems are very difficult to be solved, even numerically. Here we introduce the correlated hyperspherical harmonics as basis functions to solve the hyperangular equation for negatively and positively charged excitons (trions) in a harmonic quantum dot. By using this method, we have calculated the energy spectra of the low-lying states of a charged exciton as a function of the radius of quantum dot. Based on symmetry analysis, the level crossover as the dot radius increases can be fully explained as the results of symmetry constraint.``

  4. Barrier Li Quantum Dots in Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    LIUYi-Min; LIXiao-Zhu; YANWen-Hong; BAOCheng-Guang

    2003-01-01

    The methods for the few-body system are introduced to investigate the states of the barrier Li quantum dots (QDs) in an arbitrary strength of magnetic field. The configuration, which consists of a positive ion located on the z-axis at a distaneed from the two-dimensional QD plane (the x-y plane) and three electrons in the dot plane bound by the positive ion, is called a barrier Li center. The system, which consists of three electrons in the dot plane bound by the ion,is called a barrier Li QD. The dependence of energy of the state of the barrier Li QD on an external magnetic field B and the distance d is obtained. The angular momentum L of the ground states is found to jump not only with the variation orB but also with d.

  5. Branch management into micropipeline joint dot

    Directory of Open Access Journals (Sweden)

    Dimitar Tyanev

    2011-11-01

    Full Text Available This paper considers problems related to hardware implementation of computational process with conditional jumps. Hardware refers to asynchronous pipeline organization at microoperational level. Exploration is dedicated to one of the tasks presented in (Tyanev, D., 2009 concerning to micropipeline controller design to control micropipeline stage into joint dot of branch algorithm. Joint dot is the point at which few preceding branches are combined. It appears inevitably into conditional jump structures and this is the reason for the actuality of its problem. Analysis of this new task is presented and request arbitration functioning principles are formulated for the incoming to joint dot requests. The arbiter is responsible for the fair choice on which depends steady peformance of separate pipeline brances. Paper also describes pipeline controller synthesis and analysis of its operation in two variants: about 2-phase and 4-phase data transfer protocol. The synthesized asynchronous arbiter scheme is invariant to the type of pipeline protocol.

  6. Epidemiological features of skeletal tuberculosis at an urban district tuberculosis centre.

    Science.gov (United States)

    Chopra, Rajat; Bhatt, Rama; Biswas, S K; Bhalla, R

    2016-04-01

    Skeletal tuberculosis is an important component of extra-pulmonary tuberculosis. It can lead to substantial morbidity and poses serious occupational and economic problem. We conducted a study in an urban District Tuberculosis Centre (DTC) to assess the burden and distribution of skeletal tuberculosis in the community. Our centre was catering to a population of 6-7 lakhs between 2007 and 2012. During this period, we treated 11,274 cases of tuberculosis. Out of these, 3086 (27.3%) were cases of extrapulmonary tuberculosis and 219 (1.94%) were cases of skeletal tuberculosis. Skeletal TB predominantly affects the young Indian population with incidence peaking in the second and third decades of life. 172 patients (78.5%) in our study were new cases. There were no drugs resistant (DRTB) skeletal TB cases till we concluded our study. Tuberculosis commonly involves joints more than long bones. The spinal column was the most commonly involved skeletal site affecting 62.6% of all cases. The rate of spinal TB in our study is much higher than that reported in literature. The high number of patients calls for close co-ordination between managing orthopaedic surgeons, treating physicians and DOT providers to ensure adequate patient care. PMID:27451817

  7. Optical properties of charged semiconductor quantum dots

    Science.gov (United States)

    Jha, Praket P.

    The effect of n-type doping on the luminescence properties of II-VI quantum dots is studied. The addition of two shells of CdS on CdSe quantum dots prevents the creation of surface traps and makes the system stable under reducing environment. The injection of electrons into films of quantum dots leads to lower photoluminescence (PL) efficiency, with the extent of quenching dependent on both the number and the quantum states of the spectator charges in the nanocrystal. It is found that a 1Pe electron is an eightfold better PL quencher than the 1Se electron. Reduced threshold for stimulated emission is also observed in doped CdSe/CdS films. Time resolved photoluminescence measurements are used to extract the recombination rates of a charged exciton, called trion. It is observed that the negative trion has a radiative rate ˜2.2 +/- 0.4x faster than a neutral exciton, while its non-radiative recombination rate is slower than the biexciton non-radiative recombination rate by a factor of 7.5 +/- 1.7. The knowledge of the recombination rates of the trion enables us to calculate the quantum yield of a negative trion to be ˜10% for the nanocrystals investigated in our work. This is larger than the off state quantum yield from a single quantum dot photoluminescence trajectory and eliminates the formation of negative trion as the possible reason for the PL blinking of single quantum dots. Single quantum dot electrochemistry has also been achieved. It is shown that by varying the Fermi level of the system electrons can be reversibly injected into and extracted out of single CdSe/CdS and CdSe/ZnS nanoparticles to modulate the photoluminescence.

  8. Tele-centres as a way of achieving universal access

    DEFF Research Database (Denmark)

    Falch, Morten; Anyimadu, Amos

    2003-01-01

    The success of tele-centres in Ghana is discussed. The tele-centres offer a low cost opportunity to empower local communities in developed and developing countries to meet the challenges of the information society. The tele-centres can also contribute more directly to the supply of non-commercial...

  9. Canadian Educational Development Centre Websites: More Ebb than Flow?

    Science.gov (United States)

    Simmons, Nicola

    2010-01-01

    This paper examines information portrayed on Canadian educational development (ED) centre websites and, in particular, whether information that corresponds to questions compiled from a literature search of ED centre practices is readily available from centre websites. This study phase is part of a larger national study of Canadian educational…

  10. Photoluminescence studies of single InGaAs quantum dots

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Jensen, Jacob Riis; Hvam, Jørn Märcher

    1999-01-01

    Semiconductor quantum dots are considered a promising material system for future optical devices and quantum computers. We have studied the low-temperature photoluminescence properties of single InGaAs quantum dots embedded in GaAs. The high spatial resolution required for resolving single dots...

  11. Imaging vasculature and lymphatic flow in mice using quantum dots

    DEFF Research Database (Denmark)

    Ballou, Byron; Ernst, Lauren A.; Andreko, Susan;

    2009-01-01

    Quantum dots are ideal probes for fluorescent imaging of vascular and lymphatic tissues. On injection into appropriate sites, red- and near-infrared-emitting quantum dots provide excellent definition of vasculature, lymphoid organs, and lymph nodes draining both normal tissues and tumors. We detail...... methods for use with commercially available quantum dots and discuss common difficulties....

  12. AHE measurements of very thin films and nanosized dots

    NARCIS (Netherlands)

    Kikuchi, N.; Murillo, R.; Lodder, J.C.

    2005-01-01

    In this paper we present anomalous Hall effect analysis from very thin Co (0.5 nm) film, Co/Pt multilayers and large areas of nanosized dots as well as from a few magnetic dots having a diameter of 120 nm. The dot arrayis prepared from Co/Pt multilayer by using laser interference lithography (LIL) w

  13. Bright infrared LEDs based on colloidal quantum-dots

    KAUST Repository

    Sun, Liangfeng

    2013-01-01

    Record-brightness infrared LEDs based on colloidal quantum-dots have been achieved through control of the spacing between adjacent quantum-dots. By tuning the size of quantum-dots, the emission wavelengths can be tuned between 900nm and 1650nm. © 2013 Materials Research Society.

  14. Engineered Quantum Dot Single Photon Sources

    CERN Document Server

    Buckley, Sonia; Vuckovic, Jelena

    2012-01-01

    Fast, high efficiency, and low error single photon sources are required for implementation of a number of quantum information processing applications. The fastest triggered single photon sources to date have been demonstrated using epitaxially grown semiconductor quantum dots (QDs), which can be conveniently integrated with optical microcavities. Recent advances in QD technology, including demonstrations of high temperature and telecommunications wavelength single photon emission, have made QD single photon sources more practical. Here we discuss the applications of single photon sources and their various requirements, before reviewing the progress made on a quantum dot platform in meeting these requirements.

  15. Optical studies of capped quantum dots

    OpenAIRE

    Wuister, S.F.

    2005-01-01

    This thesis describes the synthesis and spectroscopy of CdSe and CdTe semiconductor quantum dots (QDs). The first chapter gives an introduction into the unique size dependent properties of semiconductor quantum dots. Highly luminescent QDs of CdSe and CdTe were prepared via a high temperature method in a glovebox. These QDs are soluble in organics but can be transferred into water or ethanol after exchange of the surfactants by various thiols (HS-R). For CdTe the exchange with thiols has a be...

  16. Cadmium telluride quantum dots advances and applications

    CERN Document Server

    Donegan, John

    2013-01-01

    Optical Properties of Bulk and Nanocrystalline Cadmium Telluride, Núñez Fernández and M.I. VasilevskiyAqueous Synthesis of Colloidal CdTe Nanocrystals, V. Lesnyak, N. Gaponik, and A. EychmüllerAssemblies of Thiol-Capped CdTe Nanocrystals, N. GaponikFörster Resonant Energy Transfer in CdTe Nanocrystal Quantum Dot Structures, M. Lunz and A.L. BradleyEmission of CdTe Nanocrystals Coupled to Microcavities, Y.P. Rakovich and J.F. DoneganBiological Applications of Cadmium Telluride Semiconductor Quantum Dots, A. Le Cign

  17. Resonant tunneling in graphene pseudomagnetic quantum dots.

    Science.gov (United States)

    Qi, Zenan; Bahamon, D A; Pereira, Vitor M; Park, Harold S; Campbell, D K; Neto, A H Castro

    2013-06-12

    Realistic relaxed configurations of triaxially strained graphene quantum dots are obtained from unbiased atomistic mechanical simulations. The local electronic structure and quantum transport characteristics of y-junctions based on such dots are studied, revealing that the quasi-uniform pseudomagnetic field induced by strain restricts transport to Landau level- and edge state-assisted resonant tunneling. Valley degeneracy is broken in the presence of an external field, allowing the selective filtering of the valley and chirality of the states assisting in the resonant tunneling. Asymmetric strain conditions can be explored to select the exit channel of the y-junction.

  18. Mitigation of quantum dot cytotoxicity by microencapsulation.

    Directory of Open Access Journals (Sweden)

    Amelia Romoser

    Full Text Available When CdSe/ZnS-polyethyleneimine (PEI quantum dots (QDs are microencapsulated in polymeric microcapsules, human fibroblasts are protected from acute cytotoxic effects. Differences in cellular morphology, uptake, and viability were assessed after treatment with either microencapsulated or unencapsulated dots. Specifically, QDs contained in microcapsules terminated with polyethylene glycol (PEG mitigate contact with and uptake by cells, thus providing a tool to retain particle luminescence for applications such as extracellular sensing and imaging. The microcapsule serves as the "first line of defense" for containing the QDs. This enables the individual QD coating to be designed primarily to enhance the function of the biosensor.

  19. The role of chemical additives to the phase change process of CaCl2.6H2O to optimize its performance as latent heat energy storage system

    Science.gov (United States)

    Sutjahja, I. M.; U, S. Rahayu A.; Kurniati, Nia; Pallitine, Ivyalentine D.; Kurnia, D.

    2016-08-01

    CaCl2.6H2O is one of salt hydrate based phase change material (PCM) which is suitable for room air-temperature stabilizer because it has the melting temperature just above the human comfort zone temperature (Tm ∼⃒ 29 oC) and a relatively large heat entalphy (AH ∼⃒ 190 kJ/kg). This paper reports the role of the type of chemical additives to PCM CaCl2.6H2O to the phase change process throughout the solidification process or heat release in order to optimize its performance as latent heat energy storage system. In this research we used several kinds of chemical additive, namely SrCl2.6H2O (1.0 wt%), BaCO3 (0.5 wt%), and K2CO3 (0.5 wt%). In terms of its latent time for phase change process the order the effectiveness of those chemical additives are reduced from SrCl2.6H2O, BaCO3and K2CO3. We found that this is also related to their role in suppression supercooling and phase separation effects which occurs during crystallization process of CaCl2.6H2O.

  20. The "Magic" of Tutorial Centres in Hong Kong: An Analysis of Media Marketing and Pedagogy in a Tutorial Centre

    Science.gov (United States)

    Koh, Aaron

    2014-01-01

    Why do more than three-quarters of Hong Kong's senior secondary students flock to tutorial centres like moths to light? What is the "magic" that is driving the popularity of the tutorial centre enterprise? Indeed, looking at the ongoing boom of tutorial centres in Hong Kong (there are almost 1,000 of them), it is difficult not to ask…