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Sample records for centre dot 2h2o

  1. 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

  2. H2-H2O-HI Hydrogen Separation in H2-H2O-HI Gaseous Mixture Using the Silica Membrane

    International Nuclear Information System (INIS)

    It was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical lS process. Porous alumina tube having pore size of 0.1 μm was modified by chemical vapor deposition using tetraethoxysilane. The permeance single gas of He, H2, and N2 was measured at 300-600 oC. Hydrogen permeance of the modified membrane at a permeation temperature of 600 oC was about 5.22 x 10-08 mol/Pa m2 s, and 3.2 x 10-09 of using gas mixture of H2-H2O-HI, where as HI permeances was below 1 x 10-10 mol/Pa m2 s. The Hydrogen permeance relative was not changed after 25 hours exposure in a mixture of H2-H2O-HI gas at the temperature of 450 oC. (author)

  3. Preparation, configurational and DFT-NBO analysis of nickel(II) complexes with edta-type ligands containing six-membered backbone ring : crystal structure of [Ni(H2O)(6)][Ni(1,3-pdta)]center dot 2H(2)O

    NARCIS (Netherlands)

    Belosevic, Svetlana; Vasojevic, Miorad M.; Jeremic, Marija S.; Meetsma, Auke; Matovic, Zoran D.

    2013-01-01

    New hexadentate nickel(II) complex Mg[Ni(1,3-pd3ap)]center dot 10H(2)O containing unsymmetrical edta-type ligand, 1,3-propanediamine-N,N,N '-triacetate-N-3-propionate (1,3-pd3ap), has been prepared, chromatographically separated, and characterized. Only one [trans(O-5)] of the two possible geometric

  4. Structural transition study of NiCl2.2H2O by specific heat

    International Nuclear Information System (INIS)

    The specific heat of polycrystalline NiCl2.2H2O measured in an adiabatic calorimeter by the heat-pulse method between 80 and 281 K indicates a first-order phase transition at Tc = (220.0 ± 0.5) K. This confirms a crystallographic transformation first detected by X-ray and EPR methods. (author)

  5. Study of UO2F2 - H2O - HF compounds

    International Nuclear Information System (INIS)

    We study various compounds resulting from the interaction of UO2F2 with H2O and HF (gas), and various triple compounds UO2F2 - H2O - HF; the conditions of decomposition and the thermodynamic limits of stability are specified. (author)

  6. Equilibrium coefficient of cocrystallization in the system ZnC2O4x2H2O-Mn(2)-H2O

    International Nuclear Information System (INIS)

    To determine the equilibrium volume coefficient of cocrystallization (D) of the Mn(2+) impurity, labelled by 54Mn radionuclide with sediment ZpC2O4x2H2O (Mn concentration in aqueous solution is 4x10-6 - 1.86x10-3 mol/l) three methods are used: 1) spontaneous sediment ripening; 2) sediment ripening alternating with wearing of a solid phase; 3) technique of express D determination for difficultly soluble substances in open systems. It is shown that the 1 and 2 methods lead to the same stationary state of the system for which D--0.100+-0.006, and D magnitude is not dependent on initial Mn concentration. The 3 method gives overstated magnitudes of D=O.16+-0.04

  7. Liquid water on Mars - An energy balance climate model for CO2/H2O atmospheres

    Science.gov (United States)

    Hoffert, M. I.; Callegari, A. J.; Hsieh, C. T.; Ziegler, W.

    1981-01-01

    A simple climatic model is developed for a Mars atmosphere containing CO2 and sufficient liquid water to account for the observed hydrologic surface features by the existence of a CO2/H2O greenhouse effect. A latitude-resolved climate model originally devised for terrestrial climate studies is applied to Martian conditions, with the difference between absorbed solar flux and emitted long-wave flux to space per unit area attributed to the divergence of the meridional heat flux and the poleward heat flux assumed to equal the atmospheric eddy heat flux. The global mean energy balance is calculated as a function of atmospheric pressure to assess the CO2/H2O greenhouse liquid water hypothesis, and some latitude-resolved cases are examined in detail in order to clarify the role of atmospheric transport and temperature-albedo feedback. It is shown that the combined CO2/H2O greenhouse at plausible early surface pressures may account for climates hot enough to support a hydrological cycle and running water at present-day insolation and visible albedo levels.

  8. Preparation and Molecular Structure of (SCZ)(TNPG)·2H2O

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-Yan; ZHANG Tong-Lai; ZHANG Jian-Guo

    2005-01-01

    The (SCZ)(TNPG)·2H2O prepared by mixing semicarbazide (SCZ) and trinitrophloroglucinol (TNPG) was characterized by elemental analysis and IR measurement, and its crystal structure was determined by X-ray single-crystal diffraction analysis.The crystal belongs to triclinic,0.93966(19), c = 1.1925(2) nm, α = 67.48(3), β = 77.56(3), γ = 78.93(3)°, V = 0.6908(2) nm3, Z = 2,Dc = 1.789 g/cm3, Mr = 373.23, F(000) = 384, S = 0.999 andt(MoKα) = 0.172 mm-1.The final R and wR are 0.0394 and 0.1057 for 1724 observed reflections with I > 2σ(I).It is concluded that (SCZ)(TNPG) 2H2O is an ionic compound composed of a cation SCZ+, an anion TNPG- and two water molecules.The TNPG anion and SCZ+ cation are bonded together by electrostatic attraction and hydrogen bonds, and the compound structure is stable.The thermal decomposition of (SCZ)(TNPG) 2H2O was studied by using TG-DTG and DSC techniques with a heating rate of 10 ℃/min, showing the compound contains one endothermic process of dehydrating stage and two intensive exothermic decomposition stages.The enthalpy of exothermic decomposition reaction is 452.31 kJ/mol.

  9. High purity H-2/H2O/Ni/SZ electrodes at 500 degrees C

    DEFF Research Database (Denmark)

    Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels; Norrman, Kion; Chorkendorff, Ib; Jacobsen, Torben; Mogensen, Mogens

    2013-01-01

    stabilized zirconia (SZ) with 10,13 and 18 mol% yttria and one with 6 mol% scandia plus 4 mol% yttria were studied at open circuit voltage at 400-500 degrees C in mixtures of H-2/H2O over 46 days. The polarization resistances (R-p) for all samples increased significantly during the first 10-20 days at 500......The performance of SOFC (solid oxide fuel cell) anodes is influenced negatively by impurities. In the present study segregation of impurities is minimized by using high purity materials at relatively low temperatures to prevent fast segregation. Ni point electrodes on polished single crystals of...

  10. High purity H-2/H2O/Ni/SZ electrodes at 500 degrees C

    DEFF Research Database (Denmark)

    Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels; Norrman, Kion;

    2013-01-01

    The performance of SOFC (solid oxide fuel cell) anodes is influenced negatively by impurities. In the present study segregation of impurities is minimized by using high purity materials at relatively low temperatures to prevent fast segregation. Ni point electrodes on polished single crystals...... of stabilized zirconia (SZ) with 10,13 and 18 mol% yttria and one with 6 mol% scandia plus 4 mol% yttria were studied at open circuit voltage at 400-500 degrees C in mixtures of H-2/H2O over 46 days. The polarization resistances (R-p) for all samples increased significantly during the first 10-20 days at 500...

  11. Thermodynamic study of NaCl-CdCl2-H2O system at 25 deg

    International Nuclear Information System (INIS)

    The solubility is studied and water activity is measured in the whole region concentrations of ternary solutions of the NaCl-CdCl2-H2O system at 25 deg by isothermal and isopiestic methods respectively. The solubility isotherm has two branches proper to crystallization of the 2xNaClxCdCl2x3H2O and 3xNaClx4CdCl2x14H2O complexes. Changes of isobar potential at formation of the above compounds from the system components are calculated, based on the data on phase equilibriums

  12. Volumetric Properties and Fluid Phase Equilibria of CO2 + H2O

    Energy Technology Data Exchange (ETDEWEB)

    Capobianco, Ryan [Virginia Polytechnic Institute and State University; Gruszkiewicz, Miroslaw {Mirek} S [ORNL; Wesolowski, David J [ORNL; Cole, David R [ORNL; Bodnar, Robert [Virginia Polytechnic Institute and State University

    2013-01-01

    The need for accurate modeling of fluid-mineral processes over wide ranges of temperature, pressure and composition highlighted considerable uncertainties of available property data and equations of state, even for the CO2 + H2O binary system. In particular, the solubility, activity, and ionic dissociation equilibrium data for the CO2-rich phase, which are essential for understanding dissolution/precipitation, fluid-matrix reactions, and solute transport, are uncertain or missing. In this paper we report the results of a new experimental study of volumetric and phase equilibrium properties of CO2 + H2O, to be followed by measurements for bulk and confined multicomponent fluid mixtures. Mixture densities were measured by vibrating tube densimetry (VTD) over the entire composition range at T = 200 and 250 C and P = 20, 40, 60, and 80 MPa. Initial analysis of the mutual solubilities, determined from volumetric data, shows good agreement with earlier results for the aqueous phase, but finds that the data of Takenouchi and Kennedy (1964) significantly overestimated the solubility of water in supercritical CO2 (by a factor of more than two at 200 C). Resolving this well-known discrepancy will have a direct impact on the accuracy of predictive modeling of CO2 injection in geothermal reservoirs and geological carbon sequestration through improved equations of state, needed for calibration of predictive molecular-scale models and large-scale reactive transport simulations.

  13. Redetermination of [EuCl2(H2O6]Cl

    Directory of Open Access Journals (Sweden)

    Frank Tambornino

    2014-06-01

    Full Text Available The crystal structure of the title compound, hexaaquadichloridoeuropium(III chloride, was redetermined with modern crystallographic methods. In comparison with the previous study [Lepert et al. (1983. Aust. J. Chem. 36, 477–482], it could be shown that the atomic coordinates of some O atoms had been confused and now were corrected. Moreover, it was possible to freely refine the positions of the H atoms and thus to improve the accurracy of the crystal structure. [EuCl2(H2O6]Cl crystallizes with the GdCl3·6H2O structure-type, exhibiting discrete [EuCl2(H2O6]+ cations as the main building blocks. The main blocks are linked with isolated chloride anions via O—H...Cl hydrogen bonds into a three-dimensional framework. The Eu3+ cation is located on a twofold rotation axis and is coordinated in the form of a Cl2O6 square antiprism. One chloride anion coordinates directly to Eu3+, whereas the other chloride anion, situated on a twofold rotation axis, is hydrogen bonded to six octahedrally arranged water molecules.

  14. The application of 2H2O to measure skeletal muscle protein synthesis

    Directory of Open Access Journals (Sweden)

    Fluckey James D

    2010-04-01

    Full Text Available Abstract Skeletal muscle protein synthesis has generally been determined by the precursor:product labeling approach using labeled amino acids (e.g., [13C]leucine or [13C]-, [15N]-, or [2H]phenylalanine as the tracers. Although reliable for determining rates of protein synthesis, this methodological approach requires experiments to be conducted in a controlled environment, and as a result, has limited our understanding of muscle protein renewal under free-living conditions over extended periods of time (i.e., integrative/cumulative assessments. An alternative tracer, 2H2O, has been successfully used to measure rates of muscle protein synthesis in mice, rats, fish and humans. Moreover, perturbations such as feeding and exercise have been included in these measurements without exclusion of common environmental and biological factors. In this review, we discuss the principle behind using 2H2O to measure muscle protein synthesis and highlight recent investigations that have examined the effects of feeding and exercise. The framework provided in this review should assist muscle biologists in designing experiments that advance our understanding of conditions in which anabolism is altered (e.g., exercise, feeding, growth, debilitating and metabolic pathologies.

  15. Full-dimensional, high-level ab initio potential energy surfaces for H2(H2O) and H2(H2O)2 with application to hydrogen clathrate hydrates

    Science.gov (United States)

    Homayoon, Zahra; Conte, Riccardo; Qu, Chen; Bowman, Joel M.

    2015-08-01

    New, full-dimensional potential energy surfaces (PESs), obtained using precise least-squares fitting of high-level electronic energy databases, are reported for intrinsic H2(H2O) two-body and H2(H2O)2 three-body potentials. The database for H2(H2O) consists of approximately 44 000 energies at the coupled cluster singles and doubles plus perturbative triples (CCSD(T))-F12a/haQZ (aug-cc-pVQZ for O and cc-pVQZ for H) level of theory, while the database for the three-body interaction consists of more than 36 000 energies at the CCSD(T)-F12a/haTZ (aug-cc-pVTZ for O, cc-pVTZ for H) level of theory. Two precise potentials are based on the invariant-polynomial technique and are compared to computationally faster ones obtained via "purified" symmetrization. All fits use reduced permutational symmetry appropriate for these non-covalent interactions. These intrinsic potentials are employed together with existing ones for H2, H2O, and (H2O)2, to obtain full PESs for H2(H2O) and H2(H2O)2. Properties of these full PESs are presented, including a diffusion Monte Carlo calculation of the zero-point energy and wavefunction, and dissociation energy of the H2(H2O) dimer. These PESs together with an existing one for water clusters are used in a many-body representation of the PES of hydrogen clathrate hydrates, illustrated for H2@(H2O)20. An analysis of this hydrate is presented, including the electronic dissociation energy to remove H2 from the calculated equilibrium structure.

  16. Full-dimensional, high-level ab initio potential energy surfaces for H2(H2O) and H2(H2O)2 with application to hydrogen clathrate hydrates

    International Nuclear Information System (INIS)

    New, full-dimensional potential energy surfaces (PESs), obtained using precise least-squares fitting of high-level electronic energy databases, are reported for intrinsic H2(H2O) two-body and H2(H2O)2 three-body potentials. The database for H2(H2O) consists of approximately 44 000 energies at the coupled cluster singles and doubles plus perturbative triples (CCSD(T))-F12a/haQZ (aug-cc-pVQZ for O and cc-pVQZ for H) level of theory, while the database for the three-body interaction consists of more than 36 000 energies at the CCSD(T)-F12a/haTZ (aug-cc-pVTZ for O, cc-pVTZ for H) level of theory. Two precise potentials are based on the invariant-polynomial technique and are compared to computationally faster ones obtained via “purified” symmetrization. All fits use reduced permutational symmetry appropriate for these non-covalent interactions. These intrinsic potentials are employed together with existing ones for H2, H2O, and (H2O)2, to obtain full PESs for H2(H2O) and H2(H2O)2. Properties of these full PESs are presented, including a diffusion Monte Carlo calculation of the zero-point energy and wavefunction, and dissociation energy of the H2(H2O) dimer. These PESs together with an existing one for water clusters are used in a many-body representation of the PES of hydrogen clathrate hydrates, illustrated for H2@(H2O)20. An analysis of this hydrate is presented, including the electronic dissociation energy to remove H2 from the calculated equilibrium structure

  17. Full-dimensional, high-level ab initio potential energy surfaces for H2(H2O) and H2(H2O)2 with application to hydrogen clathrate hydrates.

    Science.gov (United States)

    Homayoon, Zahra; Conte, Riccardo; Qu, Chen; Bowman, Joel M

    2015-08-28

    New, full-dimensional potential energy surfaces (PESs), obtained using precise least-squares fitting of high-level electronic energy databases, are reported for intrinsic H2(H2O) two-body and H2(H2O)2 three-body potentials. The database for H2(H2O) consists of approximately 44 000 energies at the coupled cluster singles and doubles plus perturbative triples (CCSD(T))-F12a/haQZ (aug-cc-pVQZ for O and cc-pVQZ for H) level of theory, while the database for the three-body interaction consists of more than 36 000 energies at the CCSD(T)-F12a/haTZ (aug-cc-pVTZ for O, cc-pVTZ for H) level of theory. Two precise potentials are based on the invariant-polynomial technique and are compared to computationally faster ones obtained via "purified" symmetrization. All fits use reduced permutational symmetry appropriate for these non-covalent interactions. These intrinsic potentials are employed together with existing ones for H2, H2O, and (H2O)2, to obtain full PESs for H2(H2O) and H2(H2O)2. Properties of these full PESs are presented, including a diffusion Monte Carlo calculation of the zero-point energy and wavefunction, and dissociation energy of the H2(H2O) dimer. These PESs together with an existing one for water clusters are used in a many-body representation of the PES of hydrogen clathrate hydrates, illustrated for H2@(H2O)20. An analysis of this hydrate is presented, including the electronic dissociation energy to remove H2 from the calculated equilibrium structure. PMID:26328838

  18. Studies in synthetic carbonatite systems: Solidus relationships for CaO-MgO-CO_2-H_2O to 40 kbar and CaO-MgO-SiO_2-CO_2-H_2O to 10 kbar

    OpenAIRE

    Boettcher, A. L.; Robertson, J. K.; Wyllie, P. J.

    1980-01-01

    The system CaO-MgO-SiO_2-CO_2-H_2O is an important model for many igneous and metamorphic processes, including the generation and differentiation of carbonatite and associated silicate magmas. We have experimentally established the vapor-saturated solidus for the system CaO-MgO-CO_2-H_2O from 595°C/1 kbar to

  19. Modeling Ice Giant Interiors Using Constraints on the H2-H2O Critical Curve

    Science.gov (United States)

    Bailey, E.; Stevenson, D. J.

    2015-12-01

    We present a range of models of Uranus and Neptune, taking into account recent experimental data (Bali, 2013) implying the location of the critical curve of the H2-H2O system at pressures up to 2.6 GPa. The models presented satisfy the observed total mass of each planet and the radius at the observed 1-bar pressure level. We assume the existence of three regions at different depths: an outer adiabatic envelope composed predominately of H2 and He, with a helium mass fraction 0.26, a water-rich layer including varied amounts of rock and hydrogen, and a chemically homogeneous rock core. Using measured rotation rates of Uranus and Neptune, and a density profile obtained for each model using constituent equations of state and the assumption of hydrostatic equilibrium, we calculate the gravitational harmonics J2 and J4 for comparison with observed values as an additional constraint. The H2-H2O critical curve provides information about the nature of the boundary between the outer, hydrogen-rich envelope and underlying water-rich layer. The extrapolated critical curve for hydrogen-water mixtures crosses the adiabat of the outer atmospheric shell in these models at two depths, implying a shallow outer region of limited miscibility, an intermediate region between ~90 and 98 percent of the total planet radius within which hydrogen and water can mix in all proportions, and another, deeper region of limited miscibility at less than ~90 percent of the total planet radius. The pressure and temperature of the gaseous adiabatic shell at the depth of the shallowest extent of the water-rich layer determines whether a gradual compositional transition or an ocean surface boundary may exist at depth in these planets. To satisfy the observed J2, the outer extent of the water-rich layer in these models must be located between approximately 80 and 85 percent of the total planet radius, within the deep region of limited H2-H2O miscibility, implying an ocean surface is possible within the

  20. Crystal structure of erbium trichloroacetate Er(CCl3COO)·2H2O

    International Nuclear Information System (INIS)

    X-ray structure study of Er(CCl3COO)3x2H2O crystals is conducted (SYNTEX P21 autodiffractometer, MoKα-radiation). The crystals are of triclinic syngony: a11.697 (4), b=12.790 (4), c=15223 (4) A, α=70.67 (3), β=77.80 (3), γ=6561 (3)deg; space group P1, Z=4. There are two crystallographically independent types of erbium atoms with coordination numbers 7 and 8, respectively, in the unit cell. These atoms are linked by tetra- and double-carboxylated cross-links in the endless chains, while water molecules complete the metal coordination polyhedron is within 2.259-2.393 A interval, while in seven-coordination - within 2.229-2.267 A interval. Er-H2O distances constitute 2.389-2.534 A

  1. Synergistic WO3·2H2O Nanoplates/WS2 Hybrid Catalysts for High-Efficiency Hydrogen Evolution.

    Science.gov (United States)

    Yang, Lun; Zhu, Xiaobin; Xiong, Shijie; Wu, Xinglong; Shan, Yun; Chu, Paul K

    2016-06-01

    Tungsten trioxide dihydrate (WO3·2H2O) nanoplates are prepared by in situ anodic oxidation of tungsten disulfide (WS2) film on carbon fiber paper (CFP). The WO3·2H2O/WS2 hybrid catalyst exhibits excellent synergistic effects which facilitate the kinetics of the hydrogen evolution reaction (HER). The electrochromatic effect takes place via hydrogen intercalation into WO3·2H2O. This process is accelerated by the desirable proton diffusion coefficient in the layered WO3·2H2O. Hydrogen spillover from WO3·2H2O to WS2 occurs via atomic polarization caused by the electric field of the charges on the planar defect or edge active sites of WS2. The optimized hybrid catalyst presents a geometrical current density of 100 mA cm(-2) at 152 mV overpotential with a Tafel slope of ∼54 mV per decade, making the materials one of the most active nonprecious metal HER catalysts. PMID:27211828

  2. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?

    Science.gov (United States)

    Houtkooper, Joop M.; Schulze-Makuch, Dirk

    2007-08-01

    The discovery of extremophiles on Earth is a sequence of discoveries of life in environments where it had been deemed impossible a few decades ago. The next frontier may be the Martian surface environment: could life have adapted to this harsh environment? What we learned from terrestrial extremophiles is that life adapts to every available niche where energy, liquid water and organic materials are available so that in principle metabolism and propagation are possible. A feasible adaptation mechanism to the Martian surface environment would be the incorporation of a high concentration of hydrogen peroxide in the intracellular fluid of organisms. The H2O2-H2O hypothesis suggests the existence of Martian organisms that have a mixture of H2O2 and H2O instead of salty water as their intracellular liquid (Houtkooper and Schulze-Makuch, 2007). The advantages are that the freezing point is low (the eutectic freezes at 56.5°C) and that the mixture is hygroscopic. This would enable the organisms to scavenge water from the atmosphere or from the adsorbed layers of water molecules on mineral grains, with H2O2 being also a source of oxygen. Moreover, below its freezing point the H2O2-H2O mixture has the tendency to supercool. Hydrogen peroxide is not unknown to biochemistry on Earth. There are organisms for which H2O2 plays a significant role: the bombardier beetle, Brachinus crepitans, produces a 25% H2O2 solution and, when attacked by a predator, mixes it with a fluid containing hydroquinone and a catalyst, which produces an audible steam explosion and noxious fumes. Another example is Acetobacter peroxidans, which uses H2O2 in its metabolism. H2O2 plays various other roles, such as the mediation of physiological responses such as cell proliferation, differentiation, and migration. Moreover, most eukaryotic cells contain an organelle, the peroxisome, which mediates the reactions involving H2O2. Therefore it is feasible that in the course of evolution, water-based organisms

  3. Energetic 128I reactions in Cdl2 - H2O system

    International Nuclear Information System (INIS)

    Energetic 128I reactions in gaseous and liquid phase are studied extensively by conventional retention measurements. Also a few charge plate collection experiments in liquid phase are performed. However, hot iodine atom reaction studies in water at N.T.P. by charge plate collection experiments are not reported so far. The present effort is an attempt to study the reactions of energetic 128I atoms originating from neutron bombardment of cadmium iodide in water. It is hoped that a relatively high thermal neutron capture cross section of iodine and convenient half life of 128I enable us to study favorably the high energy chemistry following 127I(n,γ)128I reaction in water. Present results are new and are critically discussed with the existing views, theories and mechanisms. It is concluded from the present investigation that the reactions of energetic iodine species in CdI2-H2O system is essentially governed by the reactivity of medium principally with the formation of reaction intermediates and/or complexes through collapsing the original molecular environment

  4. Removal of Boron in Silicon by H2-H2O Gas Mixtures

    Science.gov (United States)

    Tang, Kai; Andersson, Stefan; Nordstrand, Erlend; Tangstad, Merete

    2012-08-01

    The removal of boron in pure silicon by gas mixtures has been examined in the laboratory. Water-vapor-saturated hydrogen was used to remove boron doped in electronic-grade silicon in a vacuum frequency furnace. Boron concentrations in silicon were reduced from 52 ppm initially to 0.7 ppm and 3.4 ppm at 1450°C and 1500°C, respectively, after blowing a H2-3.2%H2O gas mixture for 180 min. The experimental results indicate that the boron removal as a function of gas-blowing time follows the law of exponential decay. After 99% of the boron is removed, approximately 90% of the silicon can be recovered. In order to better understand the gaseous refining mechanism, the quantum chemical coupled cluster with single and double excitations and a perturbative treatment of triple excitations method was used to accurately predict the enthalpy and entropy of formation of the HBO molecule. A simple refining model was then used to describe the boron refining process. This model can be used to optimize the refining efficiency.

  5. Nonisothermal Kinetice of Dehydration Process of [Sm(m-CIBA)3phen]2·2H2O and[Sm(p-CIBA)3phen]2·2H2O

    Institute of Scientific and Technical Information of China (English)

    REN Ning; WANG Xie; ZHANG Jie; ZHANG Jian-jun; XU Su-ling; ZHANG Hai-yan

    2008-01-01

    Compounds[Sm(m-CIBA)3phen]2·2H2O and[Sm(p-ClBA)3phen]2·2H2O(m-ClBA=m-chlorobenzoate,PClBA=p-chlorobenzoate,phen=1,10-phenanthroline)were prepared.The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics.The Arrhenius equation for the dehydration process can be expressed as lnk=38.65-243.90x103|RT for and△S≠ of dehydration reaction for the title compounds are determined,respectively.

  6. Radiation heterogeneous processes in the system nano-ZrO2+H2O

    International Nuclear Information System (INIS)

    Full text : In this paper, in order to determine the influence of zirconia on the radiolysis of water there were investigated the kinetics of accumulation of molecular hydrogen at the radiolytic decomposition of water in the system ZrO2 + H2O at T = 300 K. On the basis of the kinetic curves there was determined value of the process rate and radiation - chemical yield of molecular hydrogen G(H2) calculated for the energy of the absorbed water. In the operation of nuclear reactors construction materials (ZrO2) are simultaneously exposed to the influence of temperature and radiation in contact with the coolant. In this paper, in order to identify regularities of radiation, radiation-thermal processes in contact of coolant with the nanopowder of ZrO2, which is the material of nuclear reactors with water cooling there were studied the kinetics of accumulation of molecular hydrogen under the influence of gamma - radiation at different temperatures. Zirconium dioxide (ZrO2) is one of the materials, which are widely used in science and technology. ZrO2 is used in the manufacture of nuclear reactor fuel cells that convert chemical energy into electrical energy. Fuel cell devices operating at high temperatures. The use of zirconia for fuel cells due to the high ionic conductivity, which is due to the transfer of the oxygen anion vacancies. In order to ensure their high quality there are use nanoscale powders. Nanoscale systems are very different from conventional single-crystal systems. Therefore, the study of their properties under the influence of gamma - radiation is of practical and scientific interest

  7. ACIDIFICATION OF RAIN IN THE PRESENCE OF SO2, H2O2, O3, AND HNO3

    Science.gov (United States)

    The production of acid sulfate and the accumulation of acid nitrate are calculated for falling raindrops using a physico-chemical model that accounts for the mass transfer of SO2, H2O2, O3, HNO3, and CO2. The acidification is postulated to occur through the absorption of free gas...

  8. Computational study on the negative electron affinities of NO2 -.(H2O)n clusters (n=0-30).

    Science.gov (United States)

    Ejsing, Anne Marie; Brøndsted Nielsen, Steen

    2007-04-21

    Here we report negative electron affinities of NO(2)(-).(H2O)n clusters (n=0-30) obtained from density functional theory calculations and a simple correction to Koopmans' theorem. The method relies on the calculation of the detachment energy of the monoanion and its highest occupied molecular orbital and lowest unoccupied molecular orbital energies, and explicit calculations on the dianion itself are avoided. A good agreement with resonances in the cross section for neutral production in electron scattering experiments is found for n=0, 1, and 2. We find several isomeric structures of NO(2)(-).(H2O)2 of similar energy that elucidate the interplay between water-water and ion-water interactions. The topology is predicted to influence the electron affinity by 0.5 and 0.4 eV for NO(2)(-).(H2O) and NO(2)(-).(H2O)2, respectively. The electron affinity of larger clusters is shown to follow a (n+delta)-1/3 dependence, where delta=3 represents the number of water molecules that in volume, could replace NO(2) (-). PMID:17461632

  9. Chemical synthesis and characterization of hydrous tin oxide (SnO2:H2O) thin films

    Indian Academy of Sciences (India)

    S N Pusawale; P R Deshmukh; C D Lokhande

    2011-10-01

    In the present investigation, we report chemical synthesis of hydrous tin oxide (SnO2:H2O) thin films by successive ionic layer adsorption and reaction (SILAR) method at room temperature (∼300 K). The films are characterized for their structural and surface morphological properties. The formation of nanocrystalline SnO2 with porous and agglomerated particle morphology is revealed from X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies, respectively. The Fourier transform infrared spectroscopy (FTIR) study confirmed the formation of Sn–O phase and hydrous nature of the deposited film. Static water contact angle studies showed the hydrophilic nature of SnO2:H2O thin film. Electrical resistivity showed the semiconducting behaviour with room temperature electrical resistivity of 105 cm. The electrochemical properties studied in 0.5 M Na2SO4 electrolyte showed a specific capacitance of 25 F g-1 at 5 mVs-1 scan rate.

  10. Analysis of heavy water production plant using bithermal and monothermal H2/H2O isotopic exchange processes

    International Nuclear Information System (INIS)

    The analysis of the heavy water production rate was carried out numerically for a heavy water production plant composed of the 3 stages bithermal H2/H2O-isotopic exchange columns of multisection separated-bed type and monothermal H2/H2O-isotopic exchange EXEL-finisher of the same type. The production rate was influenced by the isotopic exchange efficiency in the hydrophobic Pt-catalyst bed, ηc, and in the scrubbing bed, ηb, and by the water stream cut, θ1, from the first to the second stage and θ2 from the second to the third stage and θ3 from the third to the EXEL-finisher. Finally, the D-concentration profile in the EXEL-finisher was calculated under the standard conditions. (author)

  11. Physical characterization and reactivity of the uranyl peroxide [UO2(η(2)-O2)(H2O)2]·2H2O: implications for storage of spent nuclear fuels.

    Science.gov (United States)

    Mallon, Colm; Walshe, Aurora; Forster, Robert J; Keyes, Tia E; Baker, Robert J

    2012-08-01

    The unusual uranyl peroxide studtite, [UO(2)(η(2)-O(2))(H(2)O)(2)]·2H(2)O, is a phase alteration product of spent nuclear fuel and has been characterized by solid-state cyclic voltammetry. The voltammogram exhibits two reduction waves that have been assigned to the U(VI/V) redox couple at -0.74 V and to the U(V/IV) redox couple at -1.10 V. This potential shows some dependence upon the identity of the cation of the supporting electrolyte, where cations with larger ionic radii exhibit more cathodic reduction potentials. Raman spectroelectrochemistry indicated that exhaustive reduction at either potential result in a product that does not contain peroxide linkers and is likely to be UO(2). On the basis of the reduction potentials, the unusual behavior of neptunium in the presence of studtite can be rationalized. Furthermore, the oxidation of other species relevant to the long-term storage of nuclear fuel, namely, iodine and iodide, has been explored. The phase altered product should therefore be considered as electrochemically noninnocent. Radiotracer studies with (241)Am show that it does not interact with studtite so mobility will not be retarded in repositories. Finally, a large difference in band gap energies between studtite and its dehydrated congener metastudtite has been determined from the electronic absorption spectra. PMID:22813353

  12. Hydration of calcium sulfate hemihydrate (CaSO 4· {1}/{2}H 2O) into gypsum (CaSO 4·2H 2O). The influence of the sodium poly(acrylate)/surface interaction and molecular weight

    Science.gov (United States)

    Boisvert, Jean-Philippe; Domenech, Marc; Foissy, Alain; Persello, Jacques; Mutin, Jean-Claude

    2000-12-01

    The retarding influence of sodium poly(acrylate) (PANa) on the hydration of calcium sulfate hemihydrate (CaSO 4· {1}/{2}H 2O) was investigated. This study reports the influence of sodium poly(acrylate) on hemihydrate dissolution, on homogenous and heterogeneous gypsum (CaSO 4·2H 2O) nucleation as well as on gypsum growth. It is shown that adsorption of PANa does not hinder the dissolution of hemihydrate in the present experimental conditions. The specific interaction of PANa with gypsum can explain the oriented growth of gypsum crystal. The gypsum growth is slowed down but cannot be blocked by the adsorption of PANa. On the other hand, PANa can block the heterogeneous and homogenous gypsum nucleation. As soon as a critical surface density of PANa onto the hemihydrate surface is reached, the heterogeneous gypsum nucleation is prevented and hemihydrate hydration is indefinitely blocked. The interaction between PANa and the hemihydrate surface is of prime importance to control hydration. Also, the influence of the molecular weight of PANa on homogenous nucleation has been investigated. The precipitation of calcium polyacrylate can explain the differences between the two molecular weights used (2100 and 20 000). This work leads to the conclusion that heterogeneous nucleation is the key process that controls hydration of a system in which hemihydrate dissolution, gypsum nucleation and growth are all occurring at the same time in a continuous manner.

  13. Study of T-H isotope exchange between H2-H2O by Pt-C-PTFE hydrophobic catalyst

    International Nuclear Information System (INIS)

    The preparation of Pt-C-PTFE hydrophobic catalyst is described. The experiments of T-H isotope exchange between H2/H2O by Pt-C-PTFE hydrophobic catalyst were carried out at 30 deg C, 50 deg C and 75 deg C respectively. Within the limits (9.65-38.22) cm/s, catalystic activity increases with the increase of hydrogen flow rate. The catalystic activity at 50 deg C is optimum. The catalystic activity of this catalyst between gas-liquid is larger than that between gas-vapour. Mixture of the hydrophobic catalyst with hydrophilic filler in the bed can improve hydrogen isotope exchange

  14. Degradation of Pentachlorophenol in Aqueous Solution by the UV/ZrO 2 /H 2 O 2 Photocatalytic Process

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Samarghandi

    2015-12-01

    Full Text Available Pentachlorophenol (PCP, which is one of the resistant phenolic compounds, has been classified in the category of EPA’s priority pollutants due to its high toxicity and carcinogenic potential. Therefore, its removal from water and wastewater is very important. Various methods have been studied for removing the compound, among which advanced oxidation processes (AOPs have attracted much attention because of ease of application and high efficiency. Thus the aim of this study was to investigate the efficiency of the UV/ZrO2/H2O2 process, as an AOP, for PCP removal from aquatic environments. The effects of several parameters such as ultraviolet (UV exposure time, initial PCP concentration, pH, concentration of zirconium dioxide (ZrO2 nanoparticles, and H2O2 concentration were studied. Kinetics of the reaction was also detected. The concentration of the stated materials in the samples was determined using a spectrophotometer at 500 nm. The results showed that the highest efficiency (approximately 100% was reached at optimized conditions of pH 6, contact time of 30 minutes, initial PCP concentration of 20 mg/L, the nanoparticles concentration of 0.1 g/L and H2O2 concentration of 14.7 mM/L. Also, the process followed the first order kinetics reaction. The obtained results illustrated that the UV/ZrO2/H2O2 process has a high ability in removing PCP.

  15. CO2-H2O和CO2-H2O-NaCl体系的相平衡研究进展%Progress in the Study on the Phase Equilibria of the CO2-H2O and CO2-H2O-NaCl Systems

    Institute of Scientific and Technical Information of China (English)

    吉远辉; 吉晓燕; 冯新; 刘畅; 吕玲红; 陆小华

    2007-01-01

    To study the feasibility of CO2 geological sequestration, it is needed to understand the complicated multiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological conditions (273.15 473.15K, 0-60MPa), which are also essential for designing separation equipments in chemical or oil-related industries.For this purpose, studies on the relevant phase equilibria and densities are reviewed and analyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable predictions in a wide temperature and pressure range.Besides, three different models (the electrolyte non random twoliquid (ELECNRTL), the electrolyte NRTL combining with Helgeson model (ENRTL-HG), Pitzer activity coefficient model combining with Helgeson model (PITZ-HG) are used to calculate the vapor-liquid phase equilibrium of CO2-H2O and CO2-H2O-NaCl systems.For CO2-H2O system, the calculation results agree with the experimental data very well at low and medium pressure (0-20MPa), but there are great discrepancies above 20MPa.For the water content at 473.15K, the calculated results agree with the experimental data quite well.For the CO2-H2O-NaCl system, the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCI concentration of 0.52mol·L-1.Bur for the NaCl concentration of 3.997mol·L-1,using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model.It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers.More experimental data and more accurate thermodynamic calculations are needed in high temperature and pressure ranges (above 398.15K and 31.5MPa).

  16. New coordination modes in potassium edta salts: K2[H2edta]2H2O, K3[Hedta]2H2O and K4[edta]·3.92H2O.

    Science.gov (United States)

    Krawczyk, Monika K; Lis, Tadeusz

    2011-07-01

    Three potassium edta (edta is ethylenediaminetetraacetic acid, H(4)Y) salts which have different degrees of ionization of the edta anion, namely dipotassium 2-({2-[bis(carboxylatomethyl)azaniumyl]ethyl}(carboxylatomethyl)azaniumyl)acetate dihydrate, 2K(+)·C(10)H(14)N(2)O(8)(2-)·2H(2)O, (I), tripotassium 2,2'-({2-[bis(carboxylatomethyl)amino]ethyl}ammonio)diacetate dihydrate, 3K(+)·C(10)H(13)N(2)O(8)(3-)·2H(2)O, (II), and tetrapotassium 2,2',2'',2'''-(ethane-1,2-diyldinitrilo)tetraacetate 3.92-hydrate, 4K(+)·C(10)H(12)N(2)O(8)(4-)·3.92H(2)O, (III), were obtained in crystalline form from water solutions after mixing edta with potassium hydroxide in different molar ratios. In (II), a new mode of coordination of the edta anion to the metal is observed. The HY(3-) anion contains one deprotonated N atom coordinated to K(+) and the second N atom is involved in intramolecular bifurcated N-H···O and N-H···N hydrogen bonds. The overall conformation of the HY(3-) anions is very similar to that of the Y(4-) anions in (III), although a slightly different spatial arrangement of the -CH(2)COO(-) groups in relation to (III) is observed, whereas the H(2)Y(2-) anions in (I) adopt a distinctly different geometry. The preferred synclinal conformation of the -NCH(2)CH(2)N- moiety was found for all edta anions. In all three crystals, the anions and water molecules are arranged in three-dimensional networks linked via O-H···O and C-H···O [and N-H···O in (I) and (II)] hydrogen bonds. K···O interactions also contribute to the three-dimensional polymeric architecture of the salts. PMID:21727627

  17. Spin flop relaxation in the quasi-1d Heisenberg antiferromagnet CsMnBr 3 · 2H 2O

    Science.gov (United States)

    Chirwa, M.; Top, J.; Flokstra, J.

    1983-12-01

    The relaxation phenomena associated with the antiferromagnetic to spin-flop phase transition in the quasi one dimensional Heisenberg antiferromagnet CsMnBr 3 · 2H 2O have been determined in the temperature range 1.6-4.2 K using an automatic frequency-sweeping SQUID susceptometer. Below Tλ = 2.17 K the relaxation rate τ -1 displays an exponential temperature dependence given by τ-1 = ω0 exp(- E/ kT) where ω0 = 2.48 × 10 4 s -1 and E/ k = 3.62 K, the activation energy of the relaxation process. Above Tλ broadened absorption curves and flattened Argand diagrams are observed. The ratio K1/ K2 (=0.22 ± 0.02) of the orthorhombic anisotropy constants and a weak power-law temperature dependence of the critical spin-flop field Hcr were determined.

  18. Determination of muscle protein synthesis rates in fish using (2)H2O and (2)H NMR analysis of alanine.

    Science.gov (United States)

    Marques, Cátia; Viegas, Filipa; Rito, João; Jones, John; Viegas, Ivan

    2016-09-15

    Following administration of deuterated water ((2)H2O), the fractional synthetic rate (FSR) of a given endogenous protein can be estimated by (2)H-enrichment quantification of its alanine residues. Currently, this is measured by mass spectrometry following a derivatization procedure. Muscle FSR was measured by (1)H/(2)H NMR analysis of alanine from seabass kept for 6 days in 5% (2)H-enriched saltwater, following acid hydrolysis and amino acid isolation by cation-exchange chromatography of muscle tissue. The analysis is simple and robust, and provides precise measurements of excess alanine (2)H-enrichment in the 0.1-0.4% range from 50 mmol of alanine recovered from muscle protein. PMID:27418547

  19. Synthesis and Structural Characterization of [Co(Q)2(H2O)2](Q=8-Hydroxyquinoline Ion)

    Institute of Scientific and Technical Information of China (English)

    HU Chang-wen; WANG Chun-xiu; LI Hui; NIU Xue-li; PAN Wan-long; GONG Yun

    2006-01-01

    The single crystal of bi (8-hydroxyquinoline) bihydrated cobalt ( Ⅱ ) complex, [ Co ( Q)2 ( H2O)2 ] (Q = 8-hydroxyquinoline ion), has been synthesized by general method and structurally characterized by single crystal X-ray diffraction. Crystal data: C18H16CoN2O4, monoclinic, C2/c, a = 1.336 2(4) nm, b = 0.941 2(3) nm, c = 1.354 3(4) nm, β= 109.672(4)°, Z= 4. In the complex, Co( Ⅱ ) ion is six-coordinated, forming a distorted octahedron. H-bonding and π-π stacking interaction play a significant role to form and stabilize the three-dimensional structure.

  20. Photocatalytic oxidation of nitric oxide from simulated flue gas by wet scrubbing using ultraviolet/TiO2/H2O2 process

    Institute of Scientific and Technical Information of China (English)

    张波; 仲兆平; 付宗明

    2015-01-01

    Nitric oxide (NO) from flue gas is hard to remove because of low solubility and reactivity. A new technology for photocatalytic oxidation of NO using ultraviolet (UV)/TiO2/H2O2 process is studied in an efficient laboratory-scale reactor. Effects of several key operational parameters on NO removal efficiency are studied, including TiO2 content, H2O2 initial concentration, UV lamp power, NO initial content, oxygen volume fraction and TiO2/H2O2 solution volume. The results illustrate that the NO removal efficiency increases with the increasing of H2O2 initial concentration or UV lamp power. Meanwhile, a lower NO initial content or a higher TiO2/H2O2 solution volume will result in higher NO removal efficiency. In addition, oxygen volume fraction has a little effect. The highest NO removal efficiency is achieved at the TiO2 content of 0.75 g/L, H2O2 initial concentration of 2.5 mol/L, UV lamp power of 36 W, NO initial content of 206×10−6 and TiO2/H2O2 solution volume of 600 mL. It is beneficial for the development and application of NO removal from coal-fired flue gas with UV/TiO2/H2O2 process.

  1. Synthesis of FePO4.2H2O nanoplates and their usage for fabricating superior high-rate performance LiFePO4

    International Nuclear Information System (INIS)

    Research highlights: → Monoclinic phase FePO4.2H2O nanoplates are synthesized in waterbath. → The thickness of the FePO4.2H2O nanoplates can be easily tuned. → FePO4.2H2O nanoplates are lithiated to LiFePO4/C nanoparticles. → The LiFePO4/C nanoparticles have sizes ∼50 nm, with carbon coating layer ∼2 nm. → The nanoparticles show excellent high-rate performance and long-term cyclability. - Abstract: Monoclinic phase FePO4.2H2O nanoplates are synthesized very easily in a waterbath and are lithiated to LiFePO4/C nanoparticles by a simple rheological phase method. The thickness of the nanoplates can be tuned simply by changing the concentrations of the reactants. The LiFePO4/C nanoparticles lithiated from the thin FePO4.2H2O nanoplates, with the sizes about 50 nm and the carbon coating layer at the surface 1-2 nm, show excellent high-rate performance and long-term cyclability as the cathode for lithium ion batteries, delivering discharge capacities of more than 150, 120, 110, 100, and 75 mAh g-1 at rates of 5 C, 10 C, 15 C, 20 C and 30 C, respectively.

  2. Supercapacitive performance of hydrous ruthenium oxide (RuO2.H2O) thin films synthesized by chemical route at low temperature

    Indian Academy of Sciences (India)

    P R Deshmukh; S N Pusawale; R N Bulakhe; C D Lokhande

    2013-12-01

    In the present investigation, we report the synthesis of ruthenium oxide (RuO2.H2O) thin films by simple chemical bath deposition (CBD) method at low temperature on the stainless steel substrate. The prepared thin films are characterized for their structural and morphological properties by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). The structural study revealed that the ruthenium oxide thin films are amorphous. Scanning electron microscopy study shows compact morphology with small overgrown particles on the surface of the substrate. FT–IR study confirms the formation of RuO2.H2O material. The supercapacitor behaviour of RuO2.H2O thin film was studied using cyclic voltammetry (CV) technique in 0.5 M H2SO4 electrolyte. RuO2.H2O film showed maximum specific capacitance of 192 F.g-1 at a scan rate of 20 mV.s-1. The charge–discharge studies of RuO2.H2O carried out at 300 A.cm-2 current density revealed the specific power of 1.5 kW.kg-1 and specific energy of 41.6Wh.kg-1 with 95% coulombic efficiency.

  3. Ferroelastoelectric phase transition in (NH4)2CuCl4·2H2O single crystal

    International Nuclear Information System (INIS)

    The (NH4)2CuCl4·2H2O crystal exhibits anomalous thermal, piezoelectric, dielectric and elastic properties in the vicinity of the ferroelastoelectric phase transition at TC = 200 K. Macroscopic order parameter is the h36 component of the spontaneous piezoelectric tensor connecting polarisation P3 and strain η6. The temperature change in h36 component was proportional to (TC − T)α, where α = 0.58 ± 0.05. Close to TC changes in dielectric permittivity were negligible. High value of ac conductivity in the high-temperature phase results from protons jumping between disordered ions NH4+ and between molecules of crystallisation water. Only longitudinal ultrasonic waves exhibited an abrupt change upon the phase transition. The relaxation time of the order parameter was determined from anomalous changes in attenuation of the longitudinal waves. - Highlights: • Low-temperature phase shows higher-order ferroicity: ferroelastoelectricity. • Temperature change of spontaneous piezoelectricity was studied in the ordered phase. • Dispersion of complex dielectric constant was investigated in wide temperature range. • At high-temperature phase ac conductivity is caused by proton jumps. • Anomalies of ultrasonic waves at TC were analysed using phenomenological theory

  4. How do spectral indices depend on the neutron spectrum in low enriched UO2 - H2O lattices

    International Nuclear Information System (INIS)

    The dependence of selected spectral indices SI(U8c/Dy) and SI(U8c/U5f) on the H/U ratio was studied in low enriched UO2-H2O lattices. The measurements were carried out on the basis of the parallel irradiation technique, which irradiates activation foils both in a neutron field to be investigated and in a reference field of thermal neutrons. A fuel pellet of UO2 such as those in WWER type reactors was used for the measurement of activities caused by the neutron capture of 238U and the fission of 235U. The measurements were carried out at ten different H/U ratios (in range 67 - 530) to demonstrated the capability of the present method. It was found that the results of the present measurements decrease monotonously with increasing H/U, which fully corresponds to the presumptions. The results of the measurements are useful to assess the validity of the cell calculations

  5. A New Luminescent Complex Cd(Ⅱ)-xanthene-9-carboxylate:[Cd(L)2(H2O)]n

    Institute of Scientific and Technical Information of China (English)

    SHANG Jie; WU Xiao-Yuan; WANG Fei; YANG Wen-Bin; YU Rong-Min; LU Can-Zhong

    2013-01-01

    A new luminescent Cd(Ⅱ) coordination polymer,[Cd(L)2(H2O)]n 1 (HL =xan-thene-9-carboxylic acid),was synthesized hydrothermally and characterized by satisfactory elemental analysis,FT-IR spectra and single-crystal X-ray diffraction.The crystal is of orthorhombic system,space group P212121 with a =6.4548(4),b =13.0876(12),c =27.466(2) (A),V =2320.3(3)(A)3,C28H20CdO7,Mr =580.84,Z =4,Dc =1.663 g/cm3,F(000) =1168,μ =0.990 mm-1,Flack parameter =0.00(2),the final R =0.0296 and wR =0.0691 for 5301 observed reflections (Ⅰ> 2σ(Ⅰ)).1 features a one-dimensional (1D) carboxylate oxygen-bridged inorganic chain,which is further connected by intermolecular hydrogen bonds into a three-dimensional (3D) framework.Moreover,compound 1 exhibits strong photoluminescence in the solid state at room temperature.

  6. CO2, H2O exchange and stomatal regulation of regenerated Camptotheca acuminata plantlets during ex vitro acclimatization

    Institute of Scientific and Technical Information of China (English)

    WANG Hui-mei; LI Yan-hua; GAO Yin-xiang; ZU Yuan-gang

    2006-01-01

    For finding the changes in CO2, H2O exchange and their stomatal regulation during ex vitro acclimatization of regenerated Camptotheca acuminata plantlets, the net photosynthesis rate (Pn), respiration rate (Rd), light compensation point (Lc) and light saturation point (Ls), transpiration rate (Tr), stomatal conductance (gs) and water use efficiency(WUE) were measured during 37 days of ex vitro acclimatization. The results showed that Pn sharply increased until 29 days, then slightly decreased. A substantial decrease in Lc and a substantial increase of Ls in the former two weeks were observed, indicating the light regime enlargement for effective leaf photosynthesis. Tr and gs abruptly decreased during the first week then linearly increased until 29days ex vitro acclimatization, reflecting the strong regulation effect of stomata on water changes of ex vitro acclimating plantlets. Stomatal regulation effect on CO2 exchange was different from that on water exchange, i.e. Pn was almost independent of gs during the first week, while Pn was significantly correlated with gs thereafter (i.e. dual patterns). Different from dual patterns of gs-Pn relation, the Tr monotonously linearly increased with gs. Furthermore, WUE was almost independent on gs during the first week, while a marked decreasing tendency with gs was found thereafter. At the beginning of the acclimatization, WUE was mainly determined by photosynthetic capacity, while transpiration becomes a main determinant factor for WUE from 7 to 37 days' acclimatization.

  7. Thermal Decomposition Mechanism and Non-Isothermal Kinetics of Complex of [La2(P-MBA)6(PHEN)2]2H2O

    Institute of Scientific and Technical Information of China (English)

    张建军; 王瑞芬; 白继海; 王淑萍

    2002-01-01

    The complex of [La2(P-MBA)6(PHEN)2]2H2O (P-MBA: p-methylbenzoate and PHEN: 1,10-phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The thermal behavior of [La2(P-MBA)6(PHEN)2]2H2O in dynamic nitrogen atmosphere was investigated by TG-DTG techniques. The results show that the thermal decomposition process of the [La2(P-MBA)6(PHEN)2]2H2O occurs in five steps. The empirical kinetic model for the first-step thermal decomposition obtained by Malek method is SB(m,n). The activation energy E and the pre-exponential factor lnA for this step reaction are 76.4 kJ*mol-1 and 24.92, respectively.

  8. On the Impact of HO2-H2O Complexes in the Marine Boundary Layer: A Possible Sink for HO2

    Directory of Open Access Journals (Sweden)

    Alexander Thomas Archibald

    2011-01-01

    Full Text Available The impact of the formation of HO2-H2O adducts following reaction between H2O and HO2 and subsequent reaction of this adduct on HOx, H2O2 and O3 as a function of relative humidity in the marine boundary layer has been investigated using a zero-dimensional box model. The results of simulations with different product yields for the reaction of HO2-H2O with HO2 were compared with base case data derived from current recommendations for tropospheric modelling. It is suggested that inclusion of reactions of the HO2-H2O adduct may provide a significant sink for HO2 which has so far not been considered in models of tropospheric chemistry and depending on reaction products may have a significant impact on H2O2 and O3.

  9. Molecular structure and electron paramagnetic resonance in bis (L-valinate) copper, Cu[H2NCHCO2CH(CH3)2]2.H2O

    International Nuclear Information System (INIS)

    A magnetic structural study of the compound bis (L-valinate) copper (II) monohydrated, Cu(L-val)2.H2O, using RPE and X-ray diffraction RPE measurements were made on Cu(L-val)2.H2O monocrystals in the X band (9.7 GHz) under room temperature conditions. Both the position and width of the only observed resonance, were measured on three initially perpendicular planes. The molecular tensor components were calculated supposing axial symmetry around the coppers. (Author)

  10. Simulation of the properties of MgO-MgfCl2-H2O system by thermodynamic method

    International Nuclear Information System (INIS)

    Magnesium oxychloride cement (MOC) has been investigated by many researchers who have studied its hydration products and properties. Previous works mainly concentrated on experimental studies. This study uses a thermodynamic approach to understand the formation conditions of two major hydration products of MOC, Mg3(OH)5Cl · 4H2O (phase 5) and Mg2(OH)3Cl · 4H2O (phase 3) at room temperature. The hydration reaction equilibrium of MOC phases has been predicted by using the geochemistry speciation code PHREEQC together with the extended ‘Pitzer.dat’ database. The results show that the formation of the hydration products are controlled by MgCl2 concentration, activity of H2O and pH values of the system. The equilibrium of solid phase diagram, the solubility of different hydration phases are consistent with those results obtained from experimental studies, which validates the thermodynamic model. The phase diagram provides qualitative insights on the synthesis of pure phase 3 and phase 5. For MgO-MgCl2-H2O system, the minimum MgCl2 concentration for phase 5 and phase 3 to form are 1.47 mol · kg− 1 and 2.25 mol · kg− 1, respectively. Increasing water volume can result in the transformation from phase 5 and phase 3 to brucite. Additionally, the stability analysis suggests that phase 5 prefers to formation at a higher condition of the aMg2 +, pH and aH2O as compared to the phase 3. Phosphate can significantly influence the hydration products composition of MOC during hydration but no new phosphate appears. - Highlights: • A thermodynamic database was established for magnesium oxychloride cement system on the basis of Pitzer.dat. • Thermodynamic behaviors of magnesium oxychloride cement hydration was modeled. • Calculated phase diagram of magnesium oxychloride cement was plotted

  11. Behaviour of high purity UO2/H2O interfaces under helium beam irradiation in deaerated conditions

    International Nuclear Information System (INIS)

    A question put within the framework of the nuclear fuel storage worn in geological site is what become to them in the presence of water. The aim of a fundamental program, of PRECCI project (ECA), is to highlight the behaviour of interfaces which can be used as models for the interfaces nuclear spent fuel/water if the fuel is uranium UO2 dioxide. This doctorate is interested in the effect of the alpha activity which is the only one that exist in the spent fuel after long periods. The aim is to identify the mechanisms of alteration and of leaching of surfaces under alpha irradiation. A method is developed to irradiate UO2/H2O interfaces in deaerated conditions with the beam of He2+ produced by a cyclotron. The He2+ ions cross an UO2 disc and emerge in water with an energy of 5 MeV. Leachings under irradiation are carried with a large range of particles flux. The post-irradiation characterization of the surface of the discs realised by micro-Raman spectroscopy allowed to identify the alteration layer. It is made up of studtite UO2(O2),4H2O, and of schoepite UO3,xH2O. The analysis of the solutions shows that the uranium release strongly increases. The electrochemical properties of the interfaces under irradiation strongly differ from those before irradiation. This work allows to propose that the radiolytic species seen by the interface are it during the heterogeneous phase of evolution of the traces and are species of short lives. Modeling show that the radiolytic radicals species can migrate toward the interface and react with the UO2 surface. (author)

  12. Synchrotron X-Ray Charge-Density Study of Coordination Polymer (Mn(HCOO)2(H2O)2)∞

    International Nuclear Information System (INIS)

    Three high-quality single-crystal X-ray diffraction data sets have been measured under very different conditions on a structurally simple, but magnetically complex, coordination polymer, (Mn(HCOO)2(H2O)2)∞ (1). The first data set is a conventional 100(2) K MoKα data set, the second is a very high resolution 100(2) K data set measured on a second-generation synchrotron source, while the third data set was measured with a tiny crystal on a high brilliance third-generation synchrotron source at 16(2) K. Furthermore, the magnetic susceptibility (χ) and the heat capacity (Cp) have been measured from 2 to 300 K on pressed powder. The charge density of 1 was determined from multipole modeling of the experimental structure factors, and overall there is good agreement between the densities obtained separately from the three data sets. When considering the fine density features, the two 100 K data sets agree well with each other, but show small differences to the 16 K data set. Comparison with ab initio theory suggests that the 16 K APS data set provides the most accurate density. Topological analysis of the metal-ligand bonding, experimental 3d orbital populations on the Mn atoms, and Bader atomic charges indicate quite ionic, high-spin metal atoms. This picture is supported by the effective moment estimated from the magnetization measurements (5.840(2)μB), but it is at variance with earlier spin density measurements from polarized neutron diffraction. The magnetic ordering originates from superexchange involving covalent interactions with the ligands, and non-ionic effects are observed in the static deformation density maps as well as in plots of the valence shell charge concentrations. Overall, the present study provides a benchmark charge density that can be used in comparison with future metal formate dihydrate charge densities.

  13. Thermochemical Study on Ternary Solid Complex of La(Gly)2(Ala)3Cl3·2H2O (s)

    Institute of Scientific and Technical Information of China (English)

    Ye Lijuan; Li Qiangguo; Li Xu; Yang Dejun; Liu Yi

    2007-01-01

    The complex of lanthanum chloride with Glycine and Alanine, La(Gly)2(Ala)3Cl3·2H2O, was synthesized and characterized by IR, elementary analysis, thermogravimetric analysis, and chemical analysis. The dissolution enthalpies of LaCl3 ·7H2O(s), 2Gly(s) + 3Ala(s) and La(Gly)2(Ala)3Cl3 ·2H2O(s) were determined in 2 mol·L-1 HCl by a solution-reaction isoperibol calorimeter. By designing a thermochemical cycle in terms of Hess′ Law and through calculation, the reaction enthalpy of lanthanum chloride seven-hydrate with Glycine and Alanine was obtained: ΔrHθm (298.15 K)=(29.652±0.504) kJ·mol-1, and the standard enthalpy of formation of La(Gly)2(Ala)3Cl3·2H2O(s) ΔfHθm [La(Gly)2(Ala)3Cl3·2H2O, s, 298.15 K]=-4467.6±8.3 kJ·mol-1.

  14. Preparation and Kinetics of the Thermal Decomposition of Nanosized CuC2O4-ZnC2O4·2H2O

    Institute of Scientific and Technical Information of China (English)

    CHEN Donghua; HUANG Lianrong; TANG Wanjun

    2006-01-01

    The physical mixture of nanosized CuC2O4-ZnC2O4 · 2H2O,as precursors of CuO-ZnO, have been prepared by the one-step solid state reaction method at room temperature. The thermal decomposition processes taking place in the solid state oxalate mixture of nanometer CuC2 O4-ZnC2O4 · 2H2O have been studied in static air using TG, DSC, XRD and TEM techniques. TEM showed that the grain size of the decomposition product is 5-15 nm. The values of the activation energy Ea were determined using the isoconversional procedure of KAS method and the Ozawa method. The most possible mechanism function f(α) of the thermal decompositions of nanosized CuC2O4-ZnC2O4·2H2O are defined using the comparative method, function models of the decomposition of CuC2O4 and ZnC2O4 follow the same mechanism function "Avrami-Erofeev equation". The pre-exponential factor A is obtained on the basis of Eα and f(α), thus the thermal analysis kinetic triplet of the decompositions of nanosized CuC2 O4 -ZnC2O4·2H2O are determined.

  15. An efficient solvent-free synthesis of meso-substituted dipyrromethanes using SnCl2•2H2O catalysis

    Directory of Open Access Journals (Sweden)

    Kabeer Ahmed Shaikh

    2012-07-01

    Full Text Available Highly rapid and simple methodology has been developed for the quantitative synthesis of meso-substituted dipyrromethanes from lowest pyrrole/aldehyde ratio. The method was carried out by using SnCl2•2H2O as a catalyst under solvent free condition. The method is environmentally friendly, easy to workup, and gives excellent yield of the products.

  16. One-step fabrication of nickel nanocones by electrodeposition using CaCl2·2H2O as capping reagent

    Science.gov (United States)

    Lee, Jae Min; Jung, Kyung Kuk; Lee, Sung Ho; Ko, Jong Soo

    2016-04-01

    In this research, a method for the fabrication of nickel nanocones through the addition of CaCl2·2H2O to an electrodeposition solution was proposed. When electrodeposition was performed after CaCl2·2H2O addition, precipitation of the Ni ions onto the (2 0 0) crystal face was suppressed and anisotropic growth of the nickel electrodeposited structures was promoted. Sharper nanocones were produced with increasing concentration of CaCl2·2H2O added to the solution. Moreover, when temperature of the electrodeposition solutions approached 60 °C, the apex angle of the nanostructures decreased. In addition, the nanocones produced were applied to superhydrophobic surface modification using a plasma-polymerized fluorocarbon (PPFC) coating. When the solution temperature was maintained at 60 °C and the concentration of the added CaCl2·2H2O was 1.2 M or higher, the fabricated samples showed superhydrophobic surface properties. The proposed nickel nanocone formation method can be applied to various industrial fields that require metal nanocones, including superhydrophobic surface modification.

  17. On the Crystal Structure of [Cu(OH)2(H2O)2(4-C5H4NCOOH)2

    Institute of Scientific and Technical Information of China (English)

    Ng Seik Weng

    2003-01-01

    The compound described as [Cu(OH)2(H2O)2(4-C5H4NCOOH)2] in Chin. J. Struct. Chem., 2001, 20: 478-480 is instead the compound [Cu(H2O)4(4-C5H4NCOO)2], whose crystal structure has already been published elsewhere.

  18. Investigation of atmospheric profiles of CO2 & H2O using a novel coupled model - WRF-SPA

    Science.gov (United States)

    Smallman, L.; Moncrieff, J. B.; Williams, M.

    2012-04-01

    Vertical profiles of CO2 contain an important source of information about the distribution of sources and sinks of carbon in an ecosystem. Here, we have developed a forward running model based on combining WRF with SPA to generate vertical CO2 profiles for comparison with observations. We use these modelled profiles to infer the strength and distribution of sources and sinks of carbon and water. The specific aim of this research is to combine a high resolution (4 km) forward running meteorological model (WRF) with a modified version of a mechanistic biosphere model (SPA). The combined model is used to investigate the sources and sinks of CO2 and to explore which land surfaces contribute to vertical profiles of CO2 observed over Aberfeldy, Scotland. The profiles were collected as part of the Aerocarb, and later, CarboEurope projects. SPA provides surface fluxes calculated from coupled energy, hydrological and carbon cycles. This closely coupled representation of the biosphere provides realistic surface exchanges to drive mixing within the planetary boundary layer. In addition to the analysis of aircraft profiles, land based eddy covariance measurements of CO2, H2O and energy fluxes between the atmosphere and several different vegetation types (forest, grassland & crop land) are used for validation of surface fluxes and surface meteorology generated by WRF-SPA. Preliminary comparisons with observations has shown that WRF-SPA is capable of producing realistic annual fluxes of net carbon exchange compared to observations of a evergreen forest (obs = 3.6 tC ha-1 yr-1 ; modelled = 3.5 tC ha-1 yr-1 ) and barley field (obs = 2.6 tC ha-1 yr-1 ; modelled = 2.8 tC.ha-1 yr-1 ) during 2005 in Scotland. Forward running models have a potentially significant advantage over inverse models when investigating terrestrial carbon balance. For example, inverse models are able to model carbon sink distribution as areas which do not contribute CO2 to a given profile, while in a forward

  19. Phase Relations In The System MgO-SiO2-H2O At Lower Mantle Conditions

    Science.gov (United States)

    Walter, M. J.; Frost, J.; Kohn, S. C.; WANG, W.; Thomson, A. R.; Lord, O. T.

    2013-12-01

    Transport of water into the lower mantle within subducted slabs has important implications for understanding chemical mass transfer and dynamics in the deep mantle. Dehydration of the slab in the upper mantle strips the slab of much of its water cargo, however, a significant amount of water can be retained in nominally anhydrous phases such as olivine and its high-pressure polymorphs, and pyroxenes. These phases are not stable beyond the transition zone, and water may become bound in high-pressure, dense hydrous silicates, such as Phase D, and transported into the lower mantle. Here we report on experiments in the System MgO-SiO2-H2O made in the laser-heated diamond anvil cell in the pressure range of 25 to 60 GPa and at temperatures of ~1400 to 2000 K. Starting materials are synthesized as mixtures of MgSiO3 and SiO2 glasses plus brucite, have a range of water contents of ~ 5 to 30 mol% H2O, and include both MgO-rich (model peridotite) and SiO2-rich (model eclogite) bulk compositions. Experiments are made using multi-chambered (three or four laser-drilled 25 micron holes) Re gaskets. In order to avoid Al2O3 contamination, a ruby grain is inserted into only one of the chambers for initial pressure measurement. Post-heating pressures are measured in all chambers from the calibrated shift of the Raman singlet peak of diamond that is related to stress at the culet surface. Run products are analyzed using a combination of synchrotron X-ray diffraction and FEG-EPMA to identify synthesized phases and textural relations. Perturbations in the laser-power vs temperature function that correlate with visual movement of the sample and post-quench textural features are interpreted as the hydrous silicate solidus. We will discuss the implications of the following observations: (1) The hydrous silicate melting curve occurs at ~ 1750 to 1950 K for all compositions over the studied pressure range, (2) Phase D has a high-pressure stability limit that is only mildly dependent on

  20. Ternary Isothermal Diffusion Coefficients of NaCl-MgCl2-H2O at 25 C. 7. Seawater Composition

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D G; Lee, C M; Rard, J A

    2007-02-12

    The four diffusion coefficients D{sub ij} of the ternary system NaCl-MgCl{sub 2}-H{sub 2}O at the simplified seawater composition 0.48877 mol {center_dot} dm{sup -3} NaCl and 0.05110 mol {center_dot} dm{sup -3} MgCl{sub 2} have been remeasured at 25 C. The diffusion coefficients were obtained using both Gouy and Rayleigh interferometry with the highly precise Gosting diffusiometer. The results, which should be identical in principle, are essentially the same within or very close to their combined 'realistic' errors. This system has a cross-term D{sub 12} that is larger than the D{sub 22} main-term, where subscript 1 denotes NaCl and 2 denotes MgCl{sub 2}. The results are compared with earlier, less-precise measurements. Recommended values for this system are (D{sub 11}){sub V} = 1.432 x 10{sup -9} m{sup 2} {center_dot} sec{sup -1}, (D{sub 12}){sub V} = 0.750 x 10{sup -9} m{sup 2} {center_dot} sec{sup -1}, (D{sub 21}){sub V} = 0.0185 x 10{sup -9} m{sup 2} {center_dot} sec{sup -1}, and (D{sub 22}){sub V} = 0.728 x 10{sup -9} m{sup 2} {center_dot} sec{sup -1}.

  1. Synthesis and crystal structure of [UO2(SO4)(C6H5NO2)2(H2O)] · H2O

    International Nuclear Information System (INIS)

    Monocrystals of [UO2(SO4)(C6H5NO2)2(H2O)] · H2O (I) were studied by X-ray diffraction. The compound, which is a reaction product of uranyl sulfate and nicotinic acid, crystallizes in the monoclinic system, space group P21/m, Z = 4, a = 7.539(2) A, b = 25.598(5) A, c= 9.113(2) A, β = 102.95(3) deg. The main structural units in the crystals of I are [UO2(SO4)(C6H5NO2)2(H2O)]2 dimers. Compound I was found to belong to the AB2M31 crystal-chemical group (A = UO22+) of uranyl complexes with a cis arrangement of the bidentate bridging sulfate groups

  2. LiOH - H2O2 - H2O trinary system study for the selection of optimal conditions of lithium peroxide synthesis

    Science.gov (United States)

    Nefedov, R. A.; Ferapontov, Yu A.; Kozlova, N. P.

    2016-01-01

    Using solubility method the decay kinetics of peroxide products contained in liquid phase of LiOH - H2O2 - H2O trinary system with 2 to 6% by wt hydrogen peroxide content in liquid phase in 21 to 33 °C temperature range has been studied. Conducted studies have allowed to determine temperature and concentration limits of solid phase existence of Li2O2·H2O content, distinctness of which has been confirmed using chemical and qualitative X- ray phase analysis. Stabilizing effect of solid phase of Li2O2·H2O content on hydrogen peroxide decay contained in liquid phase of LiOH - H2O2 - H2O trinary system under conditions of experiments conducted has been shown.

  3. A Theoretical Study of the Binding of [Re6Se8(OH2(H2O4] Rhenium Clusters to DNA Purine Base Guanine

    Directory of Open Access Journals (Sweden)

    Leonor Alvarado-Soto

    2015-06-01

    Full Text Available Hexanuclear rhenium complexes are promising candidates for use as antitumor drugs. However, to date, there has been no investigation into the nature of their binding to DNA. In this study, density functional theory (DFT was used to examine the binding of [Re6Se8(OH2(H2O4] to the DNA purine base guanine. The geometrical structures of cluster-guanine adducts in water were modeled at the zero order regular approximation (ZORA-PW91 level. Calculating the bond energies allowed us to compare the cis and trans forms of the cluster, and a possible manners of interaction between [Re6Se8(OH2(H2O3] clusters and DNA was obtained and explained.

  4. Poisoning by carbon monoxide of the D2-H2O(v) exchange reaction over a platinum catalyst deposited on a hydrophobic support

    International Nuclear Information System (INIS)

    The adsorption of carbon monoxide and its poisoning effect for the D2-H2O(v) exchange reaction over Pt(0.25%)/Porapak Q (copolymer of styrene and divinylbenzene) were studied. It was found that poisoning curves at 263 K, 273 K, and 297 K were similar in shape, which suggested that the activation energy for the D2-H2O(v) exchange over Pt/Porapak Q was not changed by carbon monoxide poisoning. The adsorption of hydrogen and water on the platinum surface on which carbon monoxide was pre-adsorbed to various extents was studied and demonstrated that the pre-adsorption of carbon monoxide does not cause any appreciable decrease in the amount of adsorption of hydrogen and water, and also the rate of hydrogen adsorption, although it is an effective poison for the exchange reaction. (orig.)

  5. Structure of double cerium and potassium sulfate, 2K2SO4xCe(SO4)2x2H2O

    International Nuclear Information System (INIS)

    A diffractometric investigation of 2K2SO4xCe(SO4)2x2H2O structure is carried out. The refined compound parameters are equal to: a=12.407(2), b=11.160(2), c=13.539(2) A, β=111.63(1) deg, V=1742.6(8) A3, Z=4, dsub(calcd)=2.747(1) g/cm3, space group P21/c. Atom coordinates, interatomic distances and valent angles are presented. A conclusion is made that the compound of 2K2SO4cxCe(SO4)2x2H2O brutto-composition has K8[Ce2(SO4)8]4H2O structural formula and contains dimeric anions [(SO4)3Ce(μ-SO4)2xCe(SO4)3]8-

  6. Hydrothermal synthesis and characterization of the lutetium borate-nitrate Lu2B2O5(NO3)2·2H2O

    Science.gov (United States)

    Ortner, Teresa S.; Wurst, Klaus; Hejny, Clivia; Huppertz, Hubert

    2016-01-01

    The lutetium diborate-dinitrate Lu2B2O5(NO3)2·2H2O was discovered through a hydrothermal synthesis from Lu(NO3)3·H2O and H3BO3. The compound crystallizes in the space group P 1 ̅ (no. 2) with the lattice parameters a=789.52(5), b=988.62(6), c=1460.33(8) pm, α=90.83(1), β=101.75(1), and γ=110.02(1)° (Z=4). Isolated [B2O5]4- units show coplanar alignment and the coordinating [NO3]- groups are stacked perpendicular to the borate plane. Thereby, a novel, open arrangement solely built up from diborate and nitrate groups at a 1:1 ratio is formed. Additionally, Lu2B2O5(NO3)2·2H2O is characterized by vibrational spectroscopy (IR/Raman).

  7. Synthesis, crystal structure and EPR studies of vanadyl doped [Co(2-nbH)2(ina)2(H2O)] complex

    Science.gov (United States)

    Bozkurt, Esat; Çelik, Yunus; Çöpür, Fatma; Dege, Necmi; Topcu, Yıldıray; Karabulut, Bünyamin

    2016-08-01

    A novel aquabis(isonicotinamide-κN1)bis(2-nitrobenzoato-κ2O,O‧;κO)cobalt(II), (hereafter [Co(2-nbH)2(ina)2(H2O)]; 2-nbH: 2-nitrobenzoic acid; ina: isonicotinamide), complex was synthesized and characterized by using various techniques. The crystal structure was determined by X-ray diffraction (XRD) method. The magnetic properties of VO2+ doped [Co(2-nbH)2(ina)2(H2O)] complex were obtained by electron paramagnetic resonance (EPR) technique. The angular variation of EPR spectra shows that two different VO2+ complexes are present in the lattice. The FT-IR spectra of this compound were discussed in relation to other compounds containing 2-nitrobenzoato or isonicotinamide ligands. Thermal stability and reactivity of this complex were also studied by thermal analysis methods (TG/DTG/DTA).

  8. Hydrothermal Synthesis and Characterization of a Novel Supramolecular Network Compound [Co(IN2)(H2O)4](IN=Isonicotinate)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel supramolecular compound, [Co(IN)2(H2O)4](1), was synthesized by means of the hydrothermal method and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffraction. Though the unit cell structure of the title compound is only monomeric, all these units as building blocks are assembled into a novel three-dimensional supramolecular network via the widely hydrogen-bonding and π-π stacking interactions.

  9. Possible Processes for Origin of First Chemoheterotrophic Microorganisms with Modeling of Physiological Processes of Bacterium Bacillus subtilis as a Model System in 2H2O

    OpenAIRE

    Ignat Ignatov; Oleg Mosin

    2015-01-01

    We studied possible processes for origin of first chemoheterotrophic microorganisms with modeling of physiological processes of a Gram-positive chemoheterotrophic bacterium Bacillus subtilis, producer of purine ribonucleoside inosine as a model system in heavy water. The physiological influence of deuterium on the chemoheterotrophic bacterium B. subtilis was studied on a heavy water (HW) medium with a maximal concentration of 2H2O (89–90 atom% 2H). Also various suitable samples of hot mineral...

  10. Soil and canopy CO2, 13CO2, H2O and sensible heat flux partitions in a forest canopy inferred from concentration measurements

    OpenAIRE

    Styles, Julie M.; Raupach, Michael R.; Farquhar, Graham D.; Kolle, Olaf; Lawton, Kieran A.; Brand, Willi A.; Werner, Roland A.; Jordan, Armin; Schulze, E.-Detlef; Shibistova, Olga; Lloyd, Jon

    2002-01-01

    A canopy scale model is presented that utilises Lagrangian dispersal theory to describe the relationship between source distribution and concentration within the canopy. The present study differs from previous studies in three ways: (1) source/sink distributions are solved simultaneously for CO2, 13CO2, H2O and sensible heat to find a solution consistent with leaf-level constraints imposed by photosynthetic capacity, stomatal and boundary layer conductance, available energy and carbon isotopi...

  11. [Ni(1,10-phenanthroline2(H2O2](NO32: A Simple Coordination Complex with a Remarkably Complicated Structure that Simplifies on Heating

    Directory of Open Access Journals (Sweden)

    Timothy J. Prior

    2011-09-01

    Full Text Available Despite the simple chemical formula, [Ni(1,10-phenanthroline2(H2O2](NO32, crystallizes with a remarkably complicated 3-D hydrogen bonding supramolecular assembly. The title compound crystallizes in the monoclinic space group P21/c, with an unusually long b axis and a large cell volume. A huge asymmetric unit has been identified, containing six discrete [Ni(1,10-phen2(H2O2]2+ cations and twelve nitrate anions. Detailed analyses of the crystal structure and O-H×××O and C-H×××O hydrogen bonding interactions are reported and discussed. In this way the anion-directed assembly of the 3-D structure is illustrated. The thermal and spectroscopic properties of the compound are described. Upon heating to 308 K, the crystal undergoes a phase change to a much simpler structure with a single [Ni(1,10-phen2(H2O2]2+ cation within the asymmetric unit and unit cell volume one sixth of that at low temperature. Although the crystal decomposed during data collection, it was possible to establish the molecular packing in the high temperature form and relate it to that at low temperature.

  12. Numerical comparison among water distillation column process, monothermal and bithermal. H2/H2 O - isotopic exchange column process producing D-depleted water

    International Nuclear Information System (INIS)

    Full text: Deuterium-depleted (D-depleted) water is said to be a new anti-tumor veterinary medicine for treating cats and dogs. G. Somlyai reported the biological effect of D-depleted water which is a new possibility in cancer therapy. The authors tried to estimate numerically the size of plants producing D-depleted water, namely: (1) Water distillation column process, (2) Monothermal H2/H2O- isotopic exchange column process, (3)Bithermal H2/H2O-isotopic exchange column process, excluding H2 or H2O/NH3-isotopic exchange and H2O/H2S- isotopic exchange process from a sanitary point of view of drink water. D-depleted water, as a by-product of heavy water production by means of bithermal H2/H2O-isotopic exchange process, may be considered to be the cheapest, but in this paper the authors tried to estimate an independent and non-parasite producing D-depleted water. As the result, the water distillation column process was found to be a favourable process for the production of a cheaper D-depleted water. (authors)

  13. New bidentate non-centrosymmetric borate-malate: Synthesis, structure and characterization of RbB(DL-C4H4O5)2.H2O

    International Nuclear Information System (INIS)

    Highlights: → We obtained a new nonlinear optical compound, RbB(DL-C4H4O5)2.H2O, with a bidentate structure. → The crystal structure, thermal behaviour and second order nonlinear optical properties were presented. → RbB(DL-C4H4O5)2.H2O exhibits a strong SHG signal about 2 times that of produced by KH2PO4. - Abstract: A single crystal of RbB(DL-C4H4O5)2.H2O (RBC) has been grown with a size of up to 11 mm x 8 mm x 3 mm through slow evaporation of its precursors' solution at room temperature. The structure of RBC was determined by single-crystal X-ray diffraction. Crystal data: RBC, Mr = 378.44; orthorhombic, space group Pna21 (No. 33); cell parameters, a = 11.4938(9) A, b = 5.4021(5) A, c = 21.1696(12) A and Z = 4. It exhibits a two-dimensional layer structure down the b axis, consisting of RbO7 polyhedra, BO4 tetrahedra, malate groups, and H2O molecules. The material is second harmonic generation (SHG) active; its SHG intensity is about 2 times that of KH2PO4 (KDP).

  14. {[Cu2Br3]n[Cu(H-Leof)2]·2H2O} where Leof is Levofloxacin%{[Cu2Br3]n[Cu(H-Leof)2]·2H2O}(Leof是左氟沙星)

    Institute of Scientific and Technical Information of China (English)

    王锡森; 唐云志; 熊仁根

    2005-01-01

    The crystal structure of {[Cu2Br3]n[Cu(H-Leof)2]· 2H2O} (1) comprises of [Cu(H-Leof)2] + cations, [Cu2Br3]nanions and lattice water molecules. And anion is a 1-D chain formed through alternative Cu-Br dimer and triangular geometry. CCDC: 274841.

  15. Scale formation on ferritic and austenitic steels in high CO2/H2O containing gases simulating oxy-fuel environments

    International Nuclear Information System (INIS)

    The oxy-fuel process represents a promising technology for CO2 capture from the exhaust gas in coal fired power plants. The principle of this process consists of burning coal with pure oxygen, a recirculation of the CO2 gas produced and finally a separation of the CO2 from the combustion gases, by various methods which are presently being developed. Depending on the actual process parameters used, a number of metallic heat exchanging components will in the oxy-fuel process be subjected to service environments containing high amounts of CO2 and water vapour. In the present study, the oxidation behaviour of selected commercial ferritic and austenitic steels was investigated in simulated oxy-fuel environments at temperatures in the range 550-650 C. Thereby, the behaviour of the materials in the simulated oxy-fuel gas was compared with that in CO2, H2O and CO2-O2. The experiments showed that ferritic steels components exposed to CO2/H2O gas mixtures, may exhibit substantially higher oxidation rates than during air exposure. The oxidation rates are similar to those observed in service environments of conventional power plants; however the steels exhibit a substantially larger tendency to carburization than in conventional service gases. Austenitic steels exposed to the CO2/H2O atmospheres exhibit oxidation and carburization rates which are strongly dependent on the actual Cr content of the steel and also on component surface preparation. The paper will discuss how the individual species present in the mixed gases affect the scale formation mechanisms especially in respect to their positive or adverse effect on formation of protective chromia base oxide scales. (authors)

  16. Soil and canopy CO2, 13CO2, H2O and sensible heat flux partitions in a forest canopy inferred from concentration measurements

    International Nuclear Information System (INIS)

    A canopy scale model is presented that utilises Lagrangian dispersal theory to describe the relationship between source distribution and concentration within the canopy. The present study differs from previous studies in three ways: (1) source/sink distributions are solved simultaneously for CO2, 13CO2, H2O and sensible heat to find a solution consistent with leaf-level constraints imposed by photosynthetic capacity, stomatal and boundary layer conductance, available energy and carbon isotopic discrimination during diffusion and carboxylation; (2) the model is used to solve for parameters controlling the nonlinear source interactions rather than the sources themselves; and (3) this study used plant physiological principles to allow the incorporation of within- and above-canopy measurements of the 13C/12C ratios of CO2 as an additional constraint. Source strengths of CO2, H2O, sensible heat and 13CO2 within a Siberian mixed-coniferous forest were constrained by biochemical and energy-balance principles applied to sun and shaded leaves throughout the canopy. Parameters relating to maximum photosynthetic capacity, stomatal conductance, radiation penetration and turbulence structure were determined by the optimisation procedure to match modelled and measured concentration profiles, effectively inverting the concentration data. Ground fluxes of CO2, H2O and sensible heat were also determined by the inversion. Total ecosystem fluxes predicted from the inversion were compared to hourly averaged above-canopy eddy covariance measurements over a ten-day period, with good agreement. Model results showed that stomatal conductance and maximum photosynthetic capacity were depressed due to the low temperatures experienced during snow melt; radiation penetrated further than simple theoretical predictions because of leaf clumping and penumbra, and stability effects were important in the morning and evening. The inversion was limited by little vertical structure in the concentration

  17. Kinetics of Thermal Decomposition for Complex [Zn(C16H18FN3O3)2(NO3)2]*2H2O

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The thermal decomposition reaction of the [Zn(NFA)2(NO3)2]*2H2O(NFA=C16H18FN3O3,norfloxacin) was studied in a static atmosphere using TG-DTG and DTA methods. The thermal decomposition processes of the complex were determined and its kinetics was investigated. The kinetic parameters were obtained from analysis of the TG-DTG curves by differential and integral methods. The most pro- bable mechanism for the second stage was suggested by comparision of the kinetic parameters.

  18. A study of the electric hyperfine interaction at 57Fe in Na3Fe(CN)6.2H2O using polarized recoilless gamma radiation

    International Nuclear Information System (INIS)

    Polarimetric Moessbauer measurements have been carried out to determine the electric hyperfine hamiltonian for the 14.4 keV excited state of an 57Fe nucleus in monoclinic Na3Fe(CN)6.2H2O. The experiments were made with a single crystal sample using polarized gamma rays emitted from a magnetized source. The data were analyzed using a density matrix formalism and taking into account the change in polarization of the radiation inside the absorber of finite thickness. The quadrupole interaction is nonaxial with eta = 0.52(9) and the main principal axis of the electric field gradient lies in the ac-plane. (Auth.)

  19. Kinetics of Thermal Decomposition of Zn1-xMnxC2O4·2H2O in Air

    Institute of Scientific and Technical Information of China (English)

    CONG, Chang-Jie; HONG, Jian-He; LUO, Shi-Ting; TAO, Hai-Bo; ZHANG, Ke-Li

    2006-01-01

    Thermal decomposition processes taking place in solid state complex of Zn1-xMnxC2O4·2H2O have been investigated in air using TG-DTG/DTA, XRD and TEM techniques. TG-DTG/DTA curves showed that the decomposition proceeded through two well-defined steps with DTA peaks closely to correspond to the weight loss. XRD and formed under nonisothermal conditions, the activation energies were estimated by Friedman and Flynn-Wall-Ozawa(FWO) methods, and the most probable kinetic model has been estimated with multiple linear regression method.kJ/mol, respectively.

  20. Generation and loss of reactive oxygen species in low-temperature atmospheric-pressure RF He + O2 + H2O plasmas

    International Nuclear Information System (INIS)

    This study focuses on the generation and loss of reactive oxygen species (ROS) in low-temperature atmospheric-pressure RF (13.56 MHz) He + O2 + H2O plasmas, which are of interest for many biomedical applications. These plasmas create cocktails of ROS containing ozone, singlet oxygen, atomic oxygen, hydroxyl radicals, hydrogen peroxide and hydroperoxyl radicals, i.e. ROS of great significance as recognized by the free-radical biology community. By means of one-dimensional fluid simulations (61 species, 878 reactions), the key ROS and their generation and loss mechanisms are identified as a function of the oxygen and water content in the feed gas. Identification of the main chemical pathways can guide the optimization of He + O2 + H2O plasmas for the production of particular ROS. It is found that for a given oxygen concentration, the presence of water in the feed gas decreases the net production of oxygen-derived ROS, while for a given water concentration, the presence of oxygen enhances the net production of water-derived ROS. Although most ROS can be generated in a wide range of oxygen and water admixtures, the chemical pathways leading to their generation change significantly as a function of the feed gas composition. Therefore, care must be taken when selecting reduced chemical sets to study these plasmas. (fast track communication)

  1. A SAFT equation of state for the quaternary H2S-CO2-H2O-NaCl system

    Science.gov (United States)

    Ji, Xiaoyan; Zhu, Chen

    2012-08-01

    Phase equilibria and thermodynamic properties of the quaternary H2S-CO2-H2O-NaCl system were studied using a statistical associating fluid theory (SAFT)-based equation of state (EOS) at temperatures from 0 to 200 °C (373.15-473.15 K), pressures up to 600 bar (60 MPa) and concentrations of NaCl up to 6 mol/kgH2O. The understanding of the physical-chemical properties of this system is critical for predicting the consequences of co-injection of CO2 and H2S into geological formations (geological carbon sequestration) as an option for mitigating the global warming trend. Equation of state parameters were generated from regression of available and reliable experimental data and incorporation of existing parameters for some subsystems. Densities were predicted and compared with available experimental results. Using the EOS developed in this study, we predicted equilibrium compositions in both liquid and vapor phases, fugacity coefficients of components, the equilibrium pressures at a given composition of the H2O-rich phase in electrolyte solutions with NaCl varying from 0 to 4 mol/kgH2O, and the aqueous solution densities. These predicted values are tabulated and available as supplementary data in the electronic version online. These predictions provide information and guidance for future experiments regarding the thermodynamic properties and phase behaviors in the H2S-CO2-H2O-NaCl system.

  2. Thermochemical Properties of RE(Gly) 4Im( ClO4) 3· 2H2O(RE = La, Pr, Nd, Sm, Eu)

    Institute of Scientific and Technical Information of China (English)

    何水样; 刘向荣; 宋迪生; 胡荣祖

    2001-01-01

    The enthalpies of solution in water for five new light rare earth ternary complexes RE(Gly)4Im(ClO4)3@ 2H2O (gE =La, Pr, Nd, Sm, Eu; Gly-glycine; Im-imidazole) were measured by means of a Calvet microcalorimeter. The empirical formula of enthalpy of solution (Asol H), relative apparent molar enthalpy ( φLi ), relative partial molar enthalpy ( Li )and enthalpy of dilution (AdilH1,2) were drawn up by the data of entalpies of solution of these complexes. From three plots of the values of standard enthalpy of solution AsolHΘm, φLi,Li) versus the values of ionic radius (r) of the light rare earth elements, the grouping effect of lanthanide was observed, showing that the coordination bond between rare earth ion and ligand possesses a certain extent of the property of a covalent bond. The standard enthalpies of solution in water of similar complexes, Ce(Gly)4Im(ClO4)3@2H2O were estimated according to the plot of AsolHΘm, versus r.

  3. Synthesis and characterization of a novel layered sodium titanium silicate Na2TiSi2O7·2H2O

    International Nuclear Information System (INIS)

    A novel layered sodium titanium silicate Na2TiSi2O7·2H2O has been synthesized by the reaction of a titanium-hydrogen peroxide complex and silicic acid in alkaline media under mild hydrothermal conditions (200 degree C). The product was characterized by elemental analysis, TGA, FT-IR, MAS 29Si and 23Na NMR and X-ray spectroscopy. The intercalation reaction of n-alkylamines from the gaseous phase and the ion exchange behavior of Na2TiSi2O7·2H2O towards alkali, alkaline earth and some transition metal ions in model individual and complex solutions were studied. It was found that the layered sodium titanium silicate contains acidic hydroxyl functional groups, which results in cation uptake at pH>1.5. The high affinity of the exchanger for cesium in weakly acid and neutral solutions makes it a promising material for the treatment of some types of nuclear wastes, contaminated ground water and different biological liquors. 20 refs., 10 figs., 6 tabs

  4. Evidence of PVT anomaly boundaries of water at high pressure from compression and NaCl.2H2O dehydration experiments.

    Science.gov (United States)

    Mirwald, P W

    2005-09-22

    Isothermal compression experiments on water have been performed between 0 to 80 degrees C and up to 1.3 GPa pressure. The compressibilities derived from the water compression experiments reveal a nonsmooth PVT behavior forming two anomaly boundaries. These boundaries originate at the melting line of ice III at about 0.25 GPa/-20 degrees C, and of ice VI at about 0.8 GPa/13 degrees C. Both boundaries have a positive sloped course separating three areas of different PVT properties of water. However, this P-T topology is obscured by an unresolved complication in the temperature range of 40-60 degrees C, which allows different topological interpretations of the data. As a cross-check for the compression experiment the dehydration boundary of sodium chloride-dihydrate (NaCl.2H2O) has been determined up to 1.5 GPa. The dehydration curve of NaCl.2H2O which traverses the two anomaly boundaries shows two inflections at the intersection, at 0.27 GPa/12 degrees C and at 0.77 GPa/22 degrees C, respectively. While the isothermal compressibility curves as well as the dP/dT course of the two anomaly boundaries give evidence of two densifications of water, the slope analysis of the inflections of the NaCl-2H2O dehydration curve suggests that the entropy change plays an important role. A recent model of water at high pressure conditions proposes a gradual structural transition from a low density water (LDW) at low pressures to a high density water (HDW) at high pressures. The compression data as well as the inflections of the dehydration boundary indicate, however, two discrete structural changes of water. Data comparison with that model suggests that the anomaly boundary at lower pressure corresponds to a volume fraction [V(HDW)/(V(LDW)+V(HDW))] of 0.8, while the upper one approaches a volume fraction of 1. PMID:16392519

  5. A model for the dissolution of CaO-SiO2-H2O gel at Ca/Si>1 coexisting with ettringite system considering interaction

    International Nuclear Information System (INIS)

    In this study, a dissolution model of CaO-SiO2-H2O gel at Ca/Si>1 coexisting with ettringite (AFt) system has been developed considering the interaction between C-S-H gel and AFt. The experimental results obtained in the same system were used to determine the interaction coefficients among the solid phases employing geochemical code PHREEQE. Assuming congruent dissolution of AFt, the dissolution of C-S-H gel coexisting with AFt system has been calculated incorporating these interaction coefficients into the conditional solubility products of model solids of C-S-H gel at Ca/Si>1. The calculated results of Catotal and Sitotal concentrations and pH values predicted by the present model are found to be comparable with experimental results. A complex dissolution behavior of the system are observed in the vicinity of Ca/Si∼1. (author)

  6. Dissolution phenomena of CaO-SiO2-H2O gel at Ca/Si>1 coexisting with ettringite system

    International Nuclear Information System (INIS)

    We have studied the influence of interaction between CaO-SiO2-H2O (C-S-H) gel and ettringite (AFt) on their dissolution regarding the initial chemical feature of degraded cement pore water. In this work, firstly dissolution experiments were performed in C-S-H gel at Ca/Si=1.0, 1.2 and 1.47 coexisting with AFt of which amount was 5% of mol corresponding to each C-S-H gel. Secondly, assuming the congruent dissolution of AFt, dissolution of the same system was calculated by combining with the dissolution model of C-S-H gel at 14- and SO42- with Si tetrahedra in the structure of C-S-H gel, these discrepancies are discussed in this study. (author)

  7. A new room-temperature ultraviolet emission material: K2[Ni(C2O4)2(H2O)2]·4H2O

    International Nuclear Information System (INIS)

    In this study, we investigated the crystal structure, ultraviolet (UV) luminescence, and magnetic properties of potassium bis oxalate nickel(II) tetrahydrate {K2[Ni(C2O4)2(H2O)2]·4H2O} crystals. This compound crystallizes in the monoclinic system with a P21/c space group and exhibits a one-dimensional (1D) chain structure. The Ni(II) metal center possesses an octahedral environment, with four oxygen atoms from two bidentate oxalate ligands and two oxygen atoms from water molecules. Infrared spectroscopy was used to study the vibrational modes of the compound. Interestingly, the complex exhibits intense UV emission at 364 nm when excited at 323 nm. Furthermore, the luminescence lifetime is approximately 50 µs. The magnetic susceptibility and field dependent magnetization measurements revealed a paramagnetic behavior above 20 K and antiferromagnetic ordering at low temperatures

  8. Key insights into the reacting kinetics of atmospheric pressure plasmas using He +N2 /O2 /CO2 /H2 O/Air mixtures

    Science.gov (United States)

    Murakami, Tomoyuki

    2015-09-01

    A zero dimensional kinetic chemistry computational modeling to identify the important collisional mechanisms and the dominant species in atmospheric pressure plasmas has been developed. This modeling provides an enhanced capability to tailor wide variety of reactive intermediates/species in atmospheric pressure plasmas using He +N2 /O2 /CO2 /H2 O/Air mixtures. The influence of the gas constituent, the gas temperature and the excitation frequency (kHz-, RF-, Pulsed-working) on the complex reacting chemical kinetics is clarified. This work also focuses on the benchmarking between the predictive outputs of this computer-based simulations and the diverse experimental diagnostics with particular emphasis on reactive oxygen/nitrogen intermediates/species. This work was partly supported by KAKENHI Grant Number 24561054.

  9. Switching between reaction pathways by an alcohol cosolvent effect: SmI2-ethylene glycol vs SmI2-H2O mediated synthesis of uracils.

    Science.gov (United States)

    Szostak, Michal; Spain, Malcolm; Sautier, Brice; Procter, David J

    2014-11-01

    A chemoselective switch between reaction pathways by an alcohol cosolvent effect in a general SmI2-mediated synthesis of uracil derivatives is described. The method relies on the use of coordinating solvents to increase the redox potential of Sm(II) and results in a chemoselective 1,2-reduction (SmI2-H2O) or 1,2-migration via in situ generated N-acyliminium ions (SmI2-ethylene glycol, EG). This work exploits the mild conditions of the SmI2-mediated monoreduction of barbituric acids and offers an attractive protocol for the synthesis of uracil derivatives with biological activity from readily accessible building blocks. PMID:25343692

  10. New Supramolecular Complex Assembled through Hydrogen Bonds.Crystal Structure of Co(PMBP-tsc)2·2DMF·2H2O

    Institute of Scientific and Technical Information of China (English)

    UU,Lang(刘浪); JIA,Dian-Zeng(贾殿赠); QIAO,Yong-Min(乔永民); YU,Kai-Bei(郁开北)

    2002-01-01

    The structure of the complex [Co(PMBP-tsc)2.2DMF@2H2O]( PMBP-tsc= 1-phenyl-3-methyl-4-benzoylpyrazol-5-one-thiosemicarbazone) has been determined by X-ray crystallography. It crystallizes in the orthorhombic system, space group Pna21, with lattice parameters a=2.1170(3) nm, b =1.2780(10) nm, c = 1.8956(2) nm, V= 4.5258(9) nm3 and Z=4. The structure shows that Co2+ in the complex is hexacoordinated with a distorted octahedral coordination sphere.The water molecules bridge the adjacent stacks through hydrogen bonds and lead to supramolecular formation with three-dimensional network structure.

  11. Oxidation of disinfectants with Cl-substituted structure by a Fenton-like system Cu(2+)/H2O2 and analysis on their structure-reactivity relationship.

    Science.gov (United States)

    Peng, Jianbiao; Li, Jianhua; Shi, Huanhuan; Wang, Zunyao; Gao, Shixiang

    2016-01-01

    As widely used chemicals intended to protect human being from infection of microorganisms, disinfectants are ubiquitous in the environment. Among them chlorine-substituted phenol is a basic structure in many disinfectant molecules. Removal of these pollutants from wastewater is of great concern. The oxidative degradation of antimicrobial agents such as triclosan, chlorofene, and dichlorofene by a Fenton-like system Cu(2+)/H2O2 was examined. Reaction conditions such as temperature, initial concentrations of H2O2 and Cu(2+), and pH were optimized using triclosan as a representative. The degradation kinetics of the above disinfectants followed pseudo-first-order kinetics under the investigated conditions. Fourteen chlorophenols (CPs) with different chlorine substitution were also studied to evaluate the influence of molecular structure on the degradation process in the Cu(2+)/H2O2 system. Fourteen structure-related parameters were calculated using Gaussian 09 program. A quantitative structure-activity relationship (QSAR) model was established using SPSS software with measured rate constant (k) as dependent variable and calculated molecular descriptors as independent variables. A three-parameter model including energy of HOMO (E homo), molar heat capacity at constant volume (Cv(θ)), and the most positive net charge of hydrogen atoms (qH(+)) was selected for k prediction, with correlation coefficient R(2) = 0.878. Analyses of the model demonstrated that the Cv(θ) was the most significant factor affecting the k of chlorophenols. Variance analysis and standard t-value test were used to validate the model. PMID:26408114

  12. Preparation, Crystal Structure, Thermal Decomposition and Explosive Properties of K2(tza)2(H2O) (tza -- Tetrazole-1-acetic Acid)

    Institute of Scientific and Technical Information of China (English)

    WU Bi-Dong; ZHANG Guo-Tao; ZHANG Tong-Lai; YANG Li; ZHANG Jian-Guo; ZHOU Zun-Ning; YU Kai-Bei

    2011-01-01

    A new energetic compound based on the tetrazole-l-acetic acid (tza) and potassium(I) salt, K2(tza)2(-H2O), was synthesized and characterized by elemental analysis and FT-IR spectrum. Its crystal structure was determined by single-crystal X-ray diffraction analysis. The results show that the crystal belongs to the orthorhombic system, space group Pna21 with a =1.11972(17) nm, b = 0.46647(7) nm, c = 2.5158(4) nm, V = 1.3140(3) nm3, K2C6H8N8O5, Mr=350.40 g·mol-1, Dc= 1.771 g.cm-3, μ(MoKa) = 0.759 mm-1, F(000) = 712, Z= 4, R= 0.023 and wR=0.0527 for 2961 observed reflections (I > 2σ(I)). The K(I) cation is six-coordinated with four O atoms from three carboxylate groups, one O atom from one H2O molecule and one N atom from tetrazolyl ring, in which each tza is coordinated in a tridentate chelating bridging coordination mode.The thermal decomposition mechanism of the title complex was studied by DSC and TG-DTG techniques. Under nitrogen atmosphere at a heating rate of 10 K.min-1, the thermal decomposition of the complex contains one main exothermic process between 191.7 and 243.8 C in the DSC curve.Its combustion heat was mensurated by oxygen bomb calorimetry. The non-isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa-Doyle's method, respectively.The sensitivity properties of K2(tza)2(H2O) were also determined with standard methods, which was very sensitive to flame.

  13. Hydrated copper ion chemistry: guided ion beam and computational investigation of Cu2+(H2O)n (n = 7-10) complexes.

    Science.gov (United States)

    Armentrout, Peter B; Sweeney, Andrew F

    2015-01-01

    Cross sections for the threshold collision-induced dissociation of Cu(2+)(H(2)O)(n), where n = 8 - 10, are measured using a guided ion beam tandem mass spectrometer. The primary dissociation pathway is found to be loss of a single water molecule followed by the sequential loss of additional water molecules until n = 8, at which point charge separation to form CuOH(+)(H(2)O)(4) (+) H(+)(H(2)O)(3) is observed to occur at a slightly lower energy than loss of a water molecule. Competition from charge separation prohibits the formation of appreciable amounts of the n = 7 or smaller complexes as reactants in the source. These findings indicate that Cu(2+) has a critical size of 8. Analysis of the data using statistical modeling techniques that account for energy distributions and lifetime effects yields primary and sequential bond dissociation energies (BDEs) for loss of one and two water molecules from n = 8 - 10 complexes as well as the barrier for charge separation from n = 8. More speculative analysis extends the thermochemistry obtained down to n = 5 and 6. Theoretical BDEs are determined from quantum chemical calculations using structures optimized at the B3LYP/6 311(+)G(d,p) level along with the lowest-energy isomers suggested by single point energies at the MP2(full), M06, B3LYP, and B3P86 levels of theory using a 6- 311(+)G(2d,2p) basis set. BDEs at 0K are converted to 298 K thermodynamic values using a rigid rotor/harmonic oscillator approximation. Experimental and theoretical entropies of activation suggest that a third solvent shell forms at n = 9, in accord with previous findings. The present work represents the first experimentally determined hydration enthalpies for the Cu(2+)(H(2)O)n system. PMID:26307731

  14. Obtention of agricultural gypsum traced on 34 S (Ca34 SO4.2H2O), by chemical reaction between H234 SO4 and Ca(OH)2

    International Nuclear Information System (INIS)

    The gypsum (CaSO4.2H2O) has double function in the soil: as source of calcium and sulfur and reducing agent of aluminum saturation. The sulfur for the plants has acting in the vital functions and it is proven fact increase of the S deficiency in Brazilian soils. The isotope tracer 34 S can elucidate important aspects in the sulfur cycle. The Ca34 SO4.2H2O was obtained by chemical reaction between Ca(OH)2 and H234 SO4 solution. The acid was obtained by chromatography ionic change, using cationic resin Dowex 50WX8 and Na234 SO4 solution. The reaction was realized under slow agitation. After the reaction, the precipitate was separated and dried in ventilated stove at 60 deg C temperature. The Mass of the Ca34 SO4.2H2O produced was determined by method gravimetric. This way, a system contends resin 426 cm3, considering volume of 2.2 liters can be obtained a solution contends 44.2 g of H234 SO4, theoretically could be produced 78.0 g of Ca34 SO4.2H2O approximately. With results of the tests were verified that there was not total precipitation of the Ca34SO4.2H2O. Were produced 73.7± 0.6 g of Ca34 SO4.2H2O representing average income 94.6±0.8 %. The purity of the produced CaSO4.2H2O was 98%. (author)

  15. Analysis of Heterogeneity in CO2, H2O and OH in Centimeter-Sized Obsidian Pyroclasts from Mono Craters, California

    Science.gov (United States)

    Conde, G. D.; Watkins, J. M.

    2014-12-01

    Volcanic tephra deposits typically contain inclusions or fragments of quenched melt that preserve pre-eruptive volatile concentrations within the volcanic conduit. The concentrations of CO2, H2O and OH in obsidian pyroclasts provide information on magma storage depths while gradients in these volatile species provide information on rates and mechanisms of gas loss (or gain) in magma during ascent. We are measuring CO2, H2O and OH profiles and area maps in six randomly selected pyroclastic obsidian clasts from Mono Craters, California using conventional Fourier Transform Infrared Spectroscopy (FTIR). Previous studies of these pyroclasts have focused on spot analyses of volatile concentrations within clast interiors, but our study targets clast rims, bubbles, flow bands, and texturally homogeneous regions of the clasts. The objective is to use the magnitude and spatial distribution of heterogeneities to assess the role of vapor fluxing and to determine timescales of magmatic processes such as bubble growth/resorption and mixing of magma from variable depths. The first clast that we have analyzed is relatively homogeneous in dissolved H2O and OH but exhibits millimeter-scale heterogeneities in dissolved CO2. The concentration of dissolved CO2 varies by a factor of two, ranging from 15 to 30 ppm with a patchy distribution throughout the clast. The patches of high CO2 concentration do not correspond to visible textures within the clast. Total water (H2Ot) varies from 1.5 to 1.7 wt% with higher water concentrations corresponding to darker regions of glass. The distribution of CO2 requires a mechanism for introducing millimeter-scale heterogeneity within minutes to hours prior to the eruption. Our interpretation is that obsidian pyroclasts are assembled during chaotic vertical mixing and thus sample a range of depths within the feeder system. This interpretation is consistent with previous inferences that resorption of bubbles within pyroclasts is caused by repeated

  16. A SAFT Equation of State for the Quaternary H2S-CO2-H2O-NaCl system

    Science.gov (United States)

    Ji, X.; Zhu, C.

    2011-12-01

    Phase equilibria and thermodynamic properties of the quaternary H2S-CO2-H2O-NaCl system were studied using a statistical associating fluid theory (SAFT)-based equation of state (EOS). The understanding of the physical-chemical properties of this system is critical for predicting the consequences of co-injection of CO2 and H2S into geological formations (geological carbon sequestration) as an option for mitigating the global warming trend. Previous studies of the subsystems within this quaternary have provided many parameters for the EOS. In this study, the subsystems of H2S-CO2 and H2S-H2O-NaCl were investigated in order to obtain the cross parameters for the EOS. For the binary system H2S-CO2, cross association between the site H in H2S and the site O in CO2 was allowed and temperature-independent parameters were used to describe this cross association. Meanwhile, a temperature-dependent binary interaction parameter was used to adjust the cross dispersive energy for this binary system. For the H2S-H2O-NaCl system, one temperature-dependent cross parameter was allowed in order to adjust the cross dispersive energy between H2S and ions of Na+ and Cl-. All cross parameters were fitted to the reliable phase equilibrium experimental data. Densities were predicted and compared with available experimental results. Using the EOS developed in this study, we predicted equilibrium composition in both liquid and vapor phases, the equilibrium pressures at a given composition of the H2O-rich phase in electrolyte solutions with NaCl varying from 0 to 4 mol/kgH2O, and the aqueous solution densities. These predictions provide information and guidance for future experiments regarding the thermodynamic properties and phase behaviors in the H2S-CO2-H2O-NaCl system.

  17. Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(Ⅱ) Dimer Containing Taurine Schiff Base [Zn2(C8H9N2O3S)2·(N3)2·(H2O)2]2·2H2O

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi-Min; LI Jia-Ming; XIE Fu-Qing; WANG Yan-Fei

    2006-01-01

    The title complex [Zn2L2(N3)2(H2O)2]·2H2O (L = N-(2-pyridylmethylidene) taurine)has been synthesized in a methanol-water solution. The crystal belongs to monoclinic, space group P21/c with a = 15.8064(10), b = 10.5015(5), c = 17.3193(11) (A), β = 111.314(2)°, V = 2678.2(3) (A)3, C16H26N10O10S2Zn2, Mr = 713.33, Z = 4, Dc = 1.769 g/cm3, μ = 2.017 mm-1 and F(000) =1456. The asymmetric unit consists of two half-molecules of the complex and two water molecules.Four N and two O atoms form the coordination environment of each Zn atom, resulting in a distorted octahedral configuration. The two halves of each independent dimer are related by a crystallographic inversion centre, which lies at the centre of the ring formed by two Zn atoms and the coordinating the ac plane.

  18. Synthesis and Crystal Structure of a New Mononuclear Copper(Ⅱ) Complex: [Cu(BMI)4(SO4)]·DMF·2H2O

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new copper(II) complex, [Cu(BMI)4(SO4)]·DMF·2H2O (BMI = benzimida- zole), has been synthesized by the treatment of CuCN with 2-mercaptobenzimidazole in the presence of 1,10-phenanthroline, and characterized by single-crystal X-ray diffraction. It crystalli- zes in monoclinic, space group P21/n with a = 17.6260(4), b = 11.1252(3), c = 18.6573(4)(A),β = 107.9010(10)°, V = 3481.45(14)(A)3, Z = 4, C31H35CuN9O7S, Mr = 741.28, F(000) = 1540, Dc = 1.414 g/cm3, μ = 0.746 mm-1, the final R = 0.0649 and wR = 0.1609 for 4382 observed reflections with I > 2σ(I). The Cu(II) atom is coordinated by five unidentate ligands (one sulfate and four benzimidazole ligands) generated in situ, displaying a slightly distorted square pyramid geometry.

  19. An investigation on the structure, spectroscopy and thermodynamic aspects of Br2((-))(H2O)n clusters using a conjunction of stochastic and quantum chemical methods.

    Science.gov (United States)

    Naskar, Pulak; Chaudhury, Pinaki

    2016-06-28

    In this work we obtained global as well as local structures of Br2((-))(H2O)n clusters for n = 2 to 6 followed by the study of IR-spectral features and thermochemistry for the structures. The way adopted by us to obtain structures is not the conventional one used in most cases. Here we at first generated excellent quality pre-optimized structures by exploring the suitable empirical potential energy surface using stochastic optimizer simulated annealing. These structures are then further refined using quantum chemical calculations to obtain the final structures, and spectral and thermodynamic features. We clearly showed that our approach results in very quick and better convergence which reduces the computational cost and obviously using the strategy we are able to get one [i.e. global] or more than one [i.e. global and local(s)] energetically lower structures than those which are already reported for a given cluster size. Moreover, IR-spectral results and the evolutionary trends in interaction energy, solvation energy and vertical detachment energy for global structures of each size have also been presented to establish the utility of the procedure employed. PMID:27251059

  20. Effect of O2+, H2++ O2+, and N2++ O2+ ion-beam irradiation on the field emission properties of carbon nanotubes

    International Nuclear Information System (INIS)

    The effect of O2+, H2++ O2+, and N2++ O2+ ion-beam irradiation of carbon nanotubes (CNTs) films on the chemical and electronic properties of the material is reported. The CNTs were grown by the chemical vapor deposition technique (CVD) on silicon TiN coated substrates previously decorated with Ni particles. The Ni decoration and TiN coating were successively deposited by ion-beam assisted deposition (IBAD) and afterwards the nanotubes were grown. The whole deposition procedure was performed in situ as well as the study of the effect of ion-beam irradiation on the CNTs by x-ray photoelectron spectroscopy (XPS). Raman scattering, field-effect emission gun scanning electron microscopy (FEG-SEM), and field emission (FE) measurements were performed ex situ. The experimental data show that: (a) the presence of either H2+ or N2+ ions in the irradiation beam determines the oxygen concentration remaining in the samples as well as the studied structural characteristics; (b) due to the experimental conditions used in the study, no morphological changes have been observed after irradiation of the CNTs; (c) the FE experiments indicate that the electron emission from the CNTs follows the Fowler-Nordheim model, and it is dependent on the oxygen concentration remaining in the samples; and (d) in association with FE results, the XPS data suggest that the formation of terminal quinone groups decreases the CNTs work function of the material.

  1. Composition dependent behavior in the ternary mixed magnetic insulator Co1-xMnyNix-yCl2·2H2O

    Science.gov (United States)

    DeFotis, G. C.; Hampton, A. S.; Wallin, T. J.; Trowell, K. T.; Pothen, J. M.; Welshhans, E. A.; Havas, K. C.

    2016-05-01

    The properties of ternary mixed magnetic Co1-xMnyNix-yCl2·2H2O are examined by dc magnetization and susceptibility measurements, from 1.8 to 300 K as a function of composition. This is only the second ternary magnetic insulator so studied. The three transition metal chloride dihydrate components are known to differ in the degree of spin anisotropy and in the distribution of ferromagnetic and antiferromagnetic exchange interactions within and between strongly coupled chemical and structural chains. The Curie and Weiss constants, in χM=C/(T-θ) fits to high temperature susceptibilities, are compared with weighted averages of pure component values. The observed Weiss constant is almost uniformly less negative than calculated. Maxima in low temperature susceptibilities vary widely in presence and location with composition. Some compositions exhibit no susceptibility maximum, many exhibit one maximum, and three exhibit two maxima. A T(x,y) diagram is constructed. Magnetization vs field isotherms exhibit different shapes as a function of composition, with hysteresis markedly composition dependent. For three mixtures hysteresis loops are studied as a function of temperature. An activation process model does not describe the temperature dependence well.

  2. The influence of ultraviolet illumination on OH formation in dielectric barrier discharges of Ar/O2/H2O: The Joshi effect

    International Nuclear Information System (INIS)

    The influence of ultraviolet (UV) illumination on the formation of hydroxyl radicals in dielectric barrier discharges (DBD) in mixtures of Ar/O2/H2O (79/18/3) will be presented. The UV is provided from a spectrally calibrated, commercial low pressure mercury lamp while the irradiance power of the discharge cell has been previously determined. First, the filamentary character of the DBD is shown by measurement of the relative intensity of the transition OH(A2Σ→X2Π,0-0) with integrated emission spectroscopy as a function of the absolute water concentration at different energy densities coupled into the gas. Then, the influence of UV illumination on the hydroxyl emission is shown by time-gated and time-resolved emission spectroscopy of OH(A2Σ→X2Π). The results of the combined process is an increased total emission but reduced emission for each microdischarge. This result corresponds to an increase in the number of microdischarges which is supported by the measurement of the microdischarge current. copyright 1997 American Institute of Physics

  3. EPR, ENDOR and DFT study of L-lysine·HCl·2H 2O single crystals X-irradiated at 66 K

    Science.gov (United States)

    Zhou, Yiying; Nelson, William H.

    2010-04-01

    Electron Paramagnetic Resonance (EPR), Electron-Nuclear DOuble Resonance (ENDOR) and ENDOR-Induced EPR (EIE) results indicated at least three radicals produced in L-lysine·HCl·2H 2O crystals irradiated at 66 K. EPR from radical R1 dominated the spectra and it was identified as the carboxyl anion, (H 2OOĊ) CH (NH 3) + (CH 2) 4 (NH 3) +. Density-Functional Theory (DFT) calculations supported the assignment and indicated that the carboxyl group transformed from planar to a pyramidal configuration following electron trapping. Two small couplings detected from R1 were ascribed to protons transferred to the carboxyl group from neighboring molecules through intermolecular hydrogen bonds. Radical R2 was identified as the product of decarboxylation, ĊH (NH 3) +(CH 2) 4 (NH 3) +. Although it was not possible to obtain R2's α-coupling tensor from the experiment, EPR simulations and DFT calculations provided strong support for the identification. Radical R3 exhibited several β-couplings but could be detected only in one plane and could not be identified.

  4. EPR, ENDOR and DFT study of L-lysine.HCl.2H2O single crystals X-irradiated at 66 K

    International Nuclear Information System (INIS)

    Electron Paramagnetic Resonance (EPR), Electron-Nuclear DOuble Resonance (ENDOR) and ENDOR-Induced EPR (EIE) results indicated at least three radicals produced in L-lysine.HCl.2H2O crystals irradiated at 66 K. EPR from radical R1 dominated the spectra and it was identified as the carboxyl anion, (H2OOC) CH (NH3)+ (CH2)4 (NH3)+. Density-Functional Theory (DFT) calculations supported the assignment and indicated that the carboxyl group transformed from planar to a pyramidal configuration following electron trapping. Two small couplings detected from R1 were ascribed to protons transferred to the carboxyl group from neighboring molecules through intermolecular hydrogen bonds. Radical R2 was identified as the product of decarboxylation, CH (NH3)+(CH2)4 (NH3)+. Although it was not possible to obtain R2's α-coupling tensor from the experiment, EPR simulations and DFT calculations provided strong support for the identification. Radical R3 exhibited several β-couplings but could be detected only in one plane and could not be identified.

  5. EPR, Endor and DFT Studies on X-Irradiated Single Crystals of L-Lysine HCl 2 H 2O and L-Arginine HCl H2O

    Science.gov (United States)

    Zhou, Yiying; Nelson, William H.

    2011-03-01

    When proteins and DNA interact, arginine and lysine are the two amino acids most often in close contact with the DNA. In order to understand the radiation damage to DNA in vivo, which is always associated with protein, it is important to learn the radiation chemistry of arginine and lysine independently, and then complexed to DNA. This work studied X-irradiated single crystals of L- lysine . HCl . 2 H2 O and L- arginine . HCl . H2 O with EPR, ENDOR techniques and DFT calculations. In both crystal types irradiated at 66K, the carboxyl anion radical and the decarboxylation radical were identified. Specifically, the calculations performed on the cluster models for the carboxyl anion radicals reproduced the proton transfers to the carboxyl group from the neighboring molecules through the hydrogen bonds. Moreover, computations supported the identification of one radical type within irradiated arginine as the guanidyl radical anion with an electron trapped by the guanidyl group. Based on the radicals detected in the crystal irradiated at 66K and at 298K, and the annealing experiments from the irradiation at 66K, the mechanisms of the irradiation damage on lysine and arginine were proposed, and the possible effects of irradiated arginine and lysine to the DNA within chromatin were analyzed.

  6. Thermally activated 3D to 2D structural transformation of [Ni2(en)2(H2O)6(pyr)]·4H2O flexible coordination polymer

    International Nuclear Information System (INIS)

    Thermally activated 3D to 2D structural transformation of the binuclear [Ni2(en)2(H2O)6(pyr)]·4H2O complex was investigated using a combination of theoretical and experimental methods. Step-wise thermal degradation (dehydration followed by release of ethylene diamine) results in two layered flexible coordination polymer structures. Dehydration process around 365 K results in a conjugated 2D structure with weak interlayer connectivity. It was shown to be a reversible 3D to 2D framework transformation by a guest molecule, and rehydration of the dehydration product occurs at room temperature in saturated water vapor. Rehydrated complex exhibits lower dehydration temperature, due to decreased average crystalline size, with higher surface area resulting in easier release and diffusion of water during dehydration. Thermal degradation of dehydration around 570 K, results in loss of ethylene diamine, producing a related 2D layered polymer structure, without interconnectivity between individual polymer layers. - Highlights: • Reversible 3D to 2D framework topochemical transformation on dehydration around 365 K. • Resulting polymer exhibits 2D layered structure with weak interlayer connectivity. • Dehydration is fully reversible in saturated water vapor at room temperature. • Further degradation around 570 K yields 2D polymer without interlayer connectivity. • 2D polymer exhibits conjugated electronic system

  7. Gypsum (CaSO4·2H2O Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis

    Directory of Open Access Journals (Sweden)

    Tai-Shung Chung

    2013-11-01

    Full Text Available We have examined the gypsum (CaSO4·2H2O scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO processes. Three hollow fiber membranes made of (1 cellulose acetate (CA, (2 polybenzimidazole (PBI/polyethersulfone (PES and (3 PBI-polyhedral oligomeric silsesquioxane (POSS/polyacrylonitrile (PAN were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface.

  8. Corrosion of 310 stainless steel in H2-H2O-H2S gas mixtures: Studies at constant temperature and fixed oxygen potential

    Science.gov (United States)

    Rao, D. B.; Jacob, K. T.; Nelson, H. G.

    1981-01-01

    Corrosion of SAE 310 stainless steel in H2-H2O-H2S gas mixtures was studied at a constant temperature of 1150 K. Reactive gas mixtures were chosen to yield a constant oxygen potential of approximately 6 x 10 to the minus 13th power/cu Nm and sulfur potentials ranging from 0.19 x 10 to the minus 2nd power/cu Nm to 33 x 10 to the minus 2nd power/cu Nm. The kinetics of corrosion were determined using a thermobalance, and the scales were analyzed using metallography, scanning electron microscopy, and energy dispersive X-ray analysis. Two corrosion regimes, which were dependent on sulfur potential, were identified. At high sulfur potentials (p sub S sub 2 less than or equal to 2.7 x 10 to the minus 2nd power/cu Nm) the corrosion rates were high, the kinetics obeyed a linear rate equation, and the scales consisted mainly of sulfide phases similar to those observed from pure sulfication. At low sulfur potentials (P sub S sub 2 less than or equal to 0.19 x 10 to the minus 2nd power/cu Nm) the corrosion rates were low, the kinetics obeyed a parabolic rate equation, and scales consisted mainly of oxide phases.

  9. A vibrational spectroscopic study of the silicate mineral analcime - Na2(Al4SiO4O12)·2H2O - A natural zeolite

    Science.gov (United States)

    Frost, Ray L.; López, Andrés; Theiss, Frederick L.; Romano, Antônio Wilson; Scholz, Ricardo

    2014-12-01

    We have studied the mineral analcime using a combination of scanning electron microscopy with energy dispersive spectroscopy and vibrational spectroscopy. The mineral analcime Na2(Al4SiO4O12)·2H2O is a crystalline sodium silicate. Chemical analysis shows the mineral contains a range of elements including Na, Al, Fe2+ and Si. The mineral is characterized by intense Raman bands observed at 1052, 1096 and 1125 cm-1. The infrared bands are broad; nevertheless bands may be resolved at 1006 and 1119 cm-1. These bands are assigned to SiO stretching vibrational modes. Intense Raman band at 484 cm-1 is attributed to OSiO bending modes. Raman bands observed at 2501, 3542, 3558 and 3600 cm-1 are assigned to the stretching vibrations of water. Low intensity infrared bands are noted at 3373, 3529 and 3608 cm-1. The observation of multiple water bands indicate that water is involved in the structure of analcime with differing hydrogen bond strengths. This concept is supported by the number of bands in the water bending region. Vibrational spectroscopy assists with the characterization of the mineral analcime.

  10. Hydrothermal Synthesis and Structure of a Novel Coordination Polymer Co3(tma)(pda)2(H2O)3]n·nH2O

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qiu-Xiang; BAI Xiao-Jie; CHEN Le-Pei

    2006-01-01

    A novel coordination polymer [Co3(tma)(pda)2(H2O)3]n·nH2O was synthesized by hydrothermal reaction of 3-(3-pyridyl)acrylate acid (pda) and trimesic acid (tma) with CoCl2·6H2O. The structure was characterized by elemental analysis, IR spectroscopy and X-ray single-crystal dif- fraction analysis. It crystallizes in triclinic, space group (P1)with a = 9.569(4), b = 12.562(6), c = 12.666(6)(A), α = 97.321(7), β = 110.295(7), γ = 106.110(7)°, V = 1328.9(10)(A)3, Dc = 1.877 g/cm3, Mr = 751.24, Z = 2, μ = 1.930 mm-1, F(000) = 758, the final R = 0.0392 and wR = 0.0837. The diffraction result shows that Co atoms are linked through pda and tma ligands to form an infinite three-dimensional network.

  11. Thermochemical Properties of the Complexes RE(HSal)3·2H2O (RE=La, Ce, Pr, Nd, Sm)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE(Hsal)3·2H2O(RE=La, Ce, Pr, Nd, Sm) by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE3+ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry (CV). It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes, ΔcU, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHθm, and standard molar enthalpies of formation, ΔfHθm, were calculated.

  12. Variscite (AlPO4 2H2O from Cioclovina Cave (Sureanu Mountains, Romania: a tale of a missing phosphate

    Directory of Open Access Journals (Sweden)

    Bogdan P. Onac

    2004-04-01

    Full Text Available Recent investigations on a phosphatized sediment sequence in the Cioclovina Cave led to the identification of a second occurrence in Romania (first time in the cave environment of variscite, AlPO4·2H2O. The mineral exists as dull-white, tiny crusts and veinlets within the thick argillaceous material accumulated on the cave floor. Under scanning electron microscope (SEM variscite appears as subhedral to euhedral micron-size crystals. The {111} pseudo-octahedral form is rather common. Variscite was further characterized by means of X-ray diffraction, thermal, vibrational FT-IR and FT-Raman spectroscopy, and by SEM energy-dispersive spectrometry (EDS. The calculated orthorhombic cell parameters are a = 9.823(4, b = 8.562(9, c = 9.620(5 Å, and V = 809.167(6 Å3. The ED spectrum of variscite shows well-resolved Al and P lines confirming thus the presence of the major elements in our compound. The formation of variscite is attributed to the reaction between the phosphate-rich leachates derived from guano and the underlying clay sediments.

  13. Synthesis and Crystal Structure of Co(DMSO)2(H2O)2(SCN)2 with One-dimensional Hydrogen-bonded Structure (DMSO = Dimethylsulfoxide)

    Institute of Scientific and Technical Information of China (English)

    WEI Rong-Min; CHE Yun-Xia; ZHENG Ji-Min

    2006-01-01

    The title complex Co(DMSO)2(H2O)2(SCN)2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a = 5.1981(9), b = 11.944(2), c = 12.646(2) (A), β = 98.686(2)°, V = 776.2(2) (A)3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, Dc = 1.572 g/cm3, F(000) = 378 and μ(MoKa) = 1.646 mm-1. The structure was refined to R = 0.0232 and wR = 0.0645 for 1241 observed reflections with I > 2σ(I). In the title complex, each Co(II) atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN-ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.

  14. Synthesis and Crystal Structure of Ni3(admt)6(NCS)6·C2H5OH·2H2O

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Reaction of nickel (Ⅱ) perchlorate with 4-amino-3,5-dimethyl-1,2,4-triaxole(admt)and NG4NCS gave a trinuclear complex Ni3(admtrz)6 (NCS)6·C2H5OH·2H2O,C32H58N30Ni3O3S6.The compound crystallizes in the orthorhombic space group Pbca(#61) with a=13. 551(3) , b=25.146(6), c=16.553(4) A, V=5640(2)A 3, Z=4, Mr=1279.47, Dc=1. 507 g/cm3; μ(Mo-Kα)=12.70 cm-1 and F(000) = 2656. The final refinement with 2543 observed reflections is converged with R= 0. 058 and Rw= 0. 069. In the Ni3 (admt)6 (NCS)6 molecule, the central nickel atom is coordinated in a distorted octahedral environment by four triazole bridges and two thiocyanate bridges. The terminal nickel atoms are in addition coordinated by two thiocyanate and one admtrz ligand, and thus also have a distorted octahedral geometry.Ni-N distances are 2.040(7)-2. 222(7) A, Ni-Ni distances are 3. 411(1) A.

  15. Synthesis and Crystal Structure of a Novel Three-dimensional Supramolecular Compound [(AgI3)(4-HBPFA)2(H2O)

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Fei; LI Jin-Peng; WEI Yong-Li; ZHU Yu; HOU Hong-Wei

    2005-01-01

    The supramolecular compound [(AgI3)(4-HBPFA)2(H2O)] (Mr = 1361.11) was synthesized via the reaction of 1,1(A)-bis[(4-pyridylamino)carbonyl]ferrocene (4-BPFA) with AgI, and structurally characterized by single-crystal X-ray diffraction analysis.Crystal data: monoclinic, space group C2/c, a = 1.6783(3), b = 10.646(2), c = 2.5419(5) (A), β = 93.66(3)o, V = 4532.2(16) (A)3, Z = 4, Dc = 1.995 g/cm3, F(000) = 2632 and μ = 3.158 mm-1.The compound consists of (4- HBPFA)+, (AgI3)2- and H2O.In the structure, the adjacent (4-HBPFA)+ are linked by C-H…O and N-H…N hydrogen bonds into 1-D chains which are further linked by C-H…I and N-H…I hydrogen bonds as well as intermolecular π-π stacking interactions to form a 3-D supramolecular compound.

  16. Solvothermal synthesis, crystal structure, magnetic and luminescent properties of (H3O)6.[Co4(H2O)4(HPMIDA)2(PMIDA)2)].2H2O

    International Nuclear Information System (INIS)

    A cobalt phosphonate (H3O)6.[Co4(H2O)4(HPMIDA)2(PMIDA)2)].2H2O, 1, has been synthesized from a mild solvothermal reaction of Co(II) ion with N-(phosphonomethyl)iminodiacetic acid (H4PMIDA). Compound 1 crystallizes in the triclinic space group P1-bar with cell parameters of a=9.0682(18)A, b=10.744(2)A, c=12.731(3)A, α=93.06(3)o, β=99.66(3)o, γ=90.34(3)oV=1221.0(4)A3 and Z=1. Compound 1 shows a novel tetra-nuclear molecular structure. In the crystal lattice, molecules of 1 hydrogen bond to each other to form two-dimensional (2D) layers, which are further linked together by the co-crystallized H2O molecules and H3O+ counter ions through hydrogen bonding to form the 3D supramolecular network. Thermogravimetric analysis, IR spectrum, magnetic susceptibility and luminescent spectra are given

  17. First outer-sphere 1,3-diethyl-2-thiobarbituric compounds [M(H2O)6](1,3-diethyl-2-thiobarbiturate)2·2H2O (M = Co2+, Ni2+): Crystal structure, spectroscopic and thermal properties

    Science.gov (United States)

    Golovnev, Nicolay N.; Molokeev, Maxim S.; Lesnikov, Maxim K.; Atuchin, Victor V.

    2016-06-01

    Two new d-element compounds, [Co(H2O)6](Detba)2·2H2O (1) and [Ni(H2O)6](Detba)2·2H2O (2) (HDetba - 1,3-diethyl-2-thiobarbituric acid) were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC and FT-IR. Structural analysis revealed that (1) and (2) are discrete structures, in which M2+ ion (M = Co, Ni) is six-coordinated by water molecules and it forms an octahedron. The outer-sphere Detba- ions and H2O molecules participate in Osbnd H⋯(O/S) intermolecular hydrogen bonds which form the 2D layer. Thermal decomposition includes the stage of dehydration and the following stage of oxidation of Detba- with a release of CO2, SO2, H2O, NH3 and isocyanate gases.

  18. Effect of FeSO4.7H2O and SnCl2.2H2O added as Chromium (VI) Reducers in Ordinary Portland Cement

    OpenAIRE

    Devesh K. Sharma; Rekha Sharma

    2015-01-01

    The paper compared the effect of additives such as FeSO4.2H2O and SnCl2.2H2O on reduction of water soluble Cr(VI), in ordinary Portland cement (43 grades). The determination of water soluble Cr(VI) from cement samples was precisely conducted by DPC-Spectrophotometer technique. The compressive strength testing of the cement mortar samples was carried out. In addition, hydration properties of cement paste (with and without additives) are reported in this paper. Hydration products were also stud...

  19. Investigation of Resolution and Phase Equilibria of NaCl-Ba(H2PO2)2-H2O Trio Salt-Water System at 25 °C Temperature with Isothermal Method

    OpenAIRE

    KUL, Ali Rıza; ERGE, Hasan; ÖZDEK, Uğur

    2014-01-01

    In the present research, solubility, density, conductivity and phase equilibria of Na2Cl2-Ba(H2PO2)2-H2O triple system existing in Na+, Ba+2/Cl-, (H2PO2)-H2O quadrangular mutual water-salt system were investigated by using physicochemical analysis methods. In the first place, 100 mL distilled water was added into a 100 mL volumetric flask and each time 7 g NaCl was added until solubility point of NaCl. Each addition was followed by mixing two hours and leaving one hour. Having established sol...

  20. Efficient visible light photocatalytic water oxidation on Zn3(OH)2V2O7·2H2O nanoplates: Effects of exposed facet and local crystal structure distortion

    International Nuclear Information System (INIS)

    Highlights: • Zn3(OH)2V2O7·2H2O nanoplates were hydrothermally fabricated at different pH values. • The morphology and local crystal structure of sample has a close relationship with pH. • Sample prepared at low pH exhibited the highest photocatalytic water oxidation ability. • The H2O molecule adsorption on different exposed facets was investigated by DFT. - Abstract: Zn3(OH)2V2O7·2H2O samples with high visible-light photocatalytic water oxidation activity were hydrothermally fabricated at different pH conditions. The crystalline phase, morphology and local crystal structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), corresponding selected area diffraction (SAED) and Raman techniques. According to the SEM results, all the samples exhibited aggregates of irregular nanoplates with the average diameter of 100–200 nm and thickness of ∼20 nm. Furthermore, some factors, such as pH conditions, influencing the morphologies and local crystal structure of the Zn3(OH)2V2O7·2H2O nanoplates have been systematically investigated. The photocatalytic activities of the Zn3(OH)2V2O7·2H2O were evaluated by photocatalytic water oxidation under visible light irradiation. It was found that Zn3(OH)2V2O7·2H2O prepared at low pH exhibited high photocatalytic water oxidation activity, indicating that different morphologies and the different extent of local crystal structure distortion can effectively influence the water oxidation activity of Zn3(OH)2V2O7·2H2O. Moreover, the relationship between the exposed facets of Zn3(OH)2V2O7·2H2O and the H2O molecule adsorption was investigated by density functional theory (DFT). The results of our study indicated that the extent of connection between polyhedrons on exposed facet of the Zn3(OH)2V2O7·2H2O can significantly affect the sample's H2O molecule adsorption activity

  1. Synthesis and Crystal Structure of a Mixed Complex[ Cu(1, 10-phen)(CH2(COO)2)(H2O)]2·3H2O%混配配合物[Cu(1,10-phen)(CH2(COO)2)(H2O)]2·3H2O的合成和晶体结构

    Institute of Scientific and Technical Information of China (English)

    孙绍发; 吴鸣虎; 曾卉一

    2003-01-01

    Blue block crystals of [ Cu( 1,10 - phen) ( CH2 ( COO)2 ) (H2O) ]2· 3H2O were obtained at room temperature over a period from the filtrate which was resulted from the addition of a alcohol solution of 1,10- philolin into the filtered resultant of the reaction of basic cupric carbonate with aqueous propanioic acid.Single - crystal X - ray diffraction analysis indicates that it crystallizes in a triclinic system with space group P1(No.2), α = 11.560(2),b = 11.750(2),c = 12.510(3) A,α =92.13(3)°,β= 105.50(3)°,γ=109.30(3)°, v = 1530.6(5)A3, z = 2, Mr = 781.66, F(000) = 800, Dc = 1. 696 g/cm3, μ(MoKα) =1.467 mm-1, R = 0.0392, and wR2= 0.0967 for 4560 reflections with I > 2.0σ(I). Each Cu atom is coordinated in a distorted square - pyramid geometry by two N atons of 1,10 - philolin, and two O atoms from two carboxyl group of propanioic acid, and one O atom from a coordination water molecule occupying the apical position with a long Cu - O distance. A dimer [Cu(1,10- phen) (CH2(COO)2) (H2O) ]2 is formed by the inter- molecular hydrogen bonding. The crystal structure is formed by the interconnection of the dimers and crystal water molecules via hydrogen bonding.%在碱式碳酸铜与丙二酸水溶液反应后的滤液中加入1,10-(口菲)啰啉的乙醇溶液,放置获得一种蓝色块状的晶体.X-ray衍射显示为三斜P-1群,α=11.560(2),b=11.750(2),c=12.510(3)A,α=92.13(3)°,β=105.50(3)°,γ=109.30(3)°,v=1530.6(5)A3,z=2,Mr=781.66,F(000)=800,Dc=1.696g/cm3,μ(M0Kα)=1.467mm-1,R=0.0392.二聚体[Cu(1,10-phen)(CH2(COO)2)(H2O)]2是通过分子间的氢键形成的.

  2. Possible Processes for Origin of First Chemoheterotrophic Microorganisms with Modeling of Physiological Processes of Bacterium Bacillus subtilis as a Model System in 2H2O

    Directory of Open Access Journals (Sweden)

    Ignat Ignatov

    2015-09-01

    Full Text Available We studied possible processes for origin of first chemoheterotrophic microorganisms with modeling of physiological processes of a Gram-positive chemoheterotrophic bacterium Bacillus subtilis, producer of purine ribonucleoside inosine as a model system in heavy water. The physiological influence of deuterium on the chemoheterotrophic bacterium B. subtilis was studied on a heavy water (HW medium with a maximal concentration of 2H2O (89–90 atom% 2H. Also various suitable samples of hot mineral water and sea water derived from different sources of Bulgaria were investigated using IR- and DNES-spectroscopy. It was shown that hot alkaline mineral water with temperature from +65 0C to +95 0C and pH value from 9 to 11 is more suitable for the origination of first organic forms than other analyzed water samples. There were discussed the reactions of condensation and dehydration occurring in alkaline aqueous solutions at t = +65–95 0C and рН = 9–10, resulting in synthesis from separate molecules the larger organic molecules as short polipeptides and pyrines, as well as the possible mechanisms of the deuterium accumulation in form of H2HO in hot water. The metabolism of the bacterium B. subtilis and the resistance to deuterium was also analyzed on an evolutionary level taking into account the hydrological conditions of primodial hydrosphere and the presence of H2HO, as well as the qualitative and quantitative composition of the cellular protein, amino acids and carbohydrates on media with maximum deuterium content. It was demonstrated on the example of chemoheterotrophic bacteria that first microorganisms might have been originated in hot mineral water with Ca2+ (0.5-1.0 g/l at t = + 65-95 0C and pH = 9–11, that is more suitable for maintenance and origin of life than other analyzed water samples.

  3. Phase evolution of Na2O-Al2O3-SiO2-H2O gels in synthetic aluminosilicate binders.

    Science.gov (United States)

    Walkley, Brant; San Nicolas, Rackel; Sani, Marc-Antoine; Gehman, John D; van Deventer, Jannie S J; Provis, John L

    2016-04-01

    This study demonstrates the production of stoichiometrically controlled alkali-aluminosilicate gels ('geopolymers') via alkali-activation of high-purity synthetic amorphous aluminosilicate powders. This method provides for the first time a process by which the chemistry of aluminosilicate-based cementitious materials may be accurately simulated by pure synthetic systems, allowing elucidation of physicochemical phenomena controlling alkali-aluminosilicate gel formation which has until now been impeded by the inability to isolate and control key variables. Phase evolution and nanostructural development of these materials are examined using advanced characterisation techniques, including solid state MAS NMR spectroscopy probing (29)Si, (27)Al and (23)Na nuclei. Gel stoichiometry and the reaction kinetics which control phase evolution are shown to be strongly dependent on the chemical composition of the reaction mix, while the main reaction product is a Na2O-Al2O3-SiO2-H2O type gel comprised of aluminium and silicon tetrahedra linked via oxygen bridges, with sodium taking on a charge balancing function. The alkali-aluminosilicate gels produced in this study constitute a chemically simplified model system which provides a novel research tool for the study of phase evolution and microstructural development in these systems. Novel insight of physicochemical phenomena governing geopolymer gel formation suggests that intricate control over time-dependent geopolymer physical properties can be attained through a careful precursor mix design. Chemical composition of the main N-A-S-H type gel reaction product as well as the reaction kinetics governing its formation are closely related to the Si/Al ratio of the precursor, with increased Al content leading to an increased rate of reaction and a decreased Si/Al ratio in the N-A-S-H type gel. This has significant implications for geopolymer mix design for industrial applications. PMID:26911317

  4. Experimental evaluation of water vapour cross-sensitivity for accurate eddy covariance measurement of CO2 flux using open-path CO2/H2O gas analysers

    Directory of Open Access Journals (Sweden)

    Fumiyoshi Kondo

    2014-10-01

    Full Text Available Non-dispersive infrared CO2/H2O gas analysers produce erroneous CO2 outputs when CO2 is measured in humid air, unless a correction for water vapour cross-sensitivity is applied. Spectroscopic cross-sensitivities arising from direct absorption interference and from the pressure broadening effect are significant in CO2 flux measurements by the eddy covariance technique using open-path gas analysers over the ocean, as opposed to land-surface measurements, where CO2 fluxes are orders of magnitude larger. In this study, a widely used analyser with manufacturer-determined correction coefficients for both cross-sensitivities was tested by laboratory experiments. Our results showed that the correction coefficient for direct absorption interference was not optimised to calculate CO2 flux accurately, and that the correction coefficient for the pressure broadening caused overestimation of the CO2 mixing ratio flux in the same direction as the water vapour flux. Overestimations of open-path eddy covariance measurements of upward CO2 fluxes in previous ocean observations probably resulted from inaccuracies in both of these correction coefficients. We also found that slight changes in spectroscopic cross-sensitivities due to contamination of the analyser's optical windows by sea salt caused a low bias in CO2 outputs with increasing H2O; however, this contamination effect was not always observed in repeated tests under different contamination conditions. We suggest that previously proposed methods for correcting the effect of optical window contamination is of limited value and that measurement of small CO2 fluxes by the open-path eddy covariance technique over the ocean should be performed after confirming the spectroscopic cross-sensitivity and ensuring that the optical windows are as clean as possible.

  5. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    Science.gov (United States)

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures. PMID:26328435

  6. Corrosion study on high power feeding of telecomunication copper cable in 5 wt.% CaSO4.2H2O solution

    Science.gov (United States)

    Shamsudin, Shaiful Rizam; Hashim, Nabihah; Ibrahim, Mohd Saiful Bahri; Rahman, Muhammad Sayuzi Abdul; Idrus, Muhammad Amin; Hassan, Mohd Rezadzudin; Abdullah, Wan Razli Wan

    2016-07-01

    The studies were carried out to find out the best powering scheme over the copper telephone line. It was expected that the application of the higher power feeding could increase the data transfer and capable of providing the customer's satisfaction. To realize the application of higher remote power feeding, the potential of corrosion problem on Cu cables was studied. The natural corrosion behaviour of copper cable in the 0.5% CaSO4.2H2O solution was studied in term of open circuit potential for 30 days. The corrosion behaviour of higher power feeding was studied by the immersion and the planned interval test to determine the corrosion rate as well as the effect of voltage magnitudes and the current scheme i.e. positive direct (DC+) and alternating current (AC) at about 0.40 ± 0.01 mA/ cm2 current density. In the immersion test, both DC+ and AC scheme showed the increasing of feeding voltage magnitude has increased the corrosion rate of Cu samples starting from 60 to 100 volts. It was then reduced at about 100 - 120 volts which may due to the passive and transpassive mechanism. The corrosion rate was slowly reduced further from 120 to 200 volts. Visually, the positively charged of Cu cable was seems susceptible to severe corrosion, while AC scheme exhibited a slight corrosion reaction on the surface. However, the planned interval test and XRD results showed the corrosion activity of the copper cable in the studied solution was a relatively slow process and considered not to be corroded as a partially protective scale of copper oxide formed on the surface.

  7. New zinc-glycine-iodide complexes as a product of equilibrium and non-equilibrium crystallization in the Gly - ZnI2 - H2O system

    Science.gov (United States)

    Tepavitcharova, S.; Havlíček, D.; Matulková, I.; Rabadjieva, D.; Gergulova, R.; Plocek, J.; Němec, I.; Císařová, I.

    2016-09-01

    Equilibrium crystallization of two anhydrous complex compounds, [Zn(gly)2I2] and [Zn(gly)I2], and non-equilibrium crystallization of the [Zn3(H2O)4(μ-gly)2I6] complex have been observed in the Gly - ZnI2 - H2O system at 25°C. Different mixed zinc-glycine-iodide-aqua complexes exist in the studied solutions and those with the highest activity are responsible for the crystallization process. The stable [ZnI2O2(2Gly)]0 complexes are responsible for the large equilibrium crystallization field of the compound [Zn(gly)2I2] (monoclinic system, C2/c space group), in whose crystal structure they are incorporated as discrete distorted electroneutral tetrahedra. In zinc-iodide solutions with a low water activity it is more probable that the glycine zwitterions act as bidentate ligands and form polynuclear complexes. We assume the [ZnI2O2(2/2Gly)]0 infinite chains build the compound [Zn(gly)I2], for which we have found a narrow equilibrium crystallization field. We have failed to describe the crystal structure of this compound because of its limited stability in the air. Non-equilibrium crystallization of [Zn3(H2O)4(μ-gly)2I6] (triclinic system, P-1 space group) was demonstrated, with crystal structure built by trinuclear complexes [ZnI3O(1/2Gly)] [ZnO4(4H2O)O2(2/2Gly)(trans)][ZnI3O(1/2Gly)]. The FTIR and Raman spectra and also the thermal behaviour of the three compounds were discussed.

  8. Determination of Antioxidant Activity of Chinese Herbal Medicine with RHB-Mn2+-H2O2 System by Synchronous Fluorospectrophotometry%罗丹明B-Mn2+-H2O2体系同步荧光分光光度法测定中药的抗氧化活性

    Institute of Scientific and Technical Information of China (English)

    张爱梅; 刘妮娜; 臧运波; 贾晶晶

    2007-01-01

    罗丹明B能产生特征荧光,其激发波长和发射波长分别为554 nm和575 nm.弱碱性介质中Mn2+-H2O2体系产生的羟自由基可迅速氧化罗丹明B使荧光猝灭,而中药水提取物可部分清除溶液中羟自由基,从而使其荧光猝灭程度减弱.用△λ=21 nm的同步荧光分光光度法建立了测定中药抗氧化活性的方法.测试了11种中药的抗氧化活性,以五倍子的抗氧化活性最强.

  9. The role of acid in the formation of hydrogen-bonded networks featuring 4,4'-dicarboxy-2,2'-bipyridine (H2dcbp): Synthesis, structural and magnetic characterisation of {[Cu(H2dcbp)Cl2].H2O}2 and [Cu(H2dcbp)(NO3)2(H2O)

    OpenAIRE

    Tynan, Eithne; Jensen, Paul; Lees, Anthea C.; Moubaraki, Boujemaa; Murray, Keith S.; Kruger, Paul E.

    2005-01-01

    Reported herein are the synthesis, structural and magnetic characterisation of two hydrogen-bonded networks featuring the 4,4?-dicarboxy-2,2?-bipyridine (H2dcbp) ligand: {[Cu(H2dcbp)(Cl)2]·H2O}2 1 and [Cu(H2dcbp)(NO3)2(H2O)] 2. Compounds 1 and 2 result from the reaction of CuCl2 and Cu(NO3)2, respectively, with H2dcbp under hydrothermal conditions in the presence of either HCl or HNO3. The acid ensures that H2dcbp remains protonated and provides the anions required for charge balance irrespec...

  10. Formation of new double salt NaCl · CdSO4 · 5H2O in 2NaCl + CdSO4 = Na2SO4 + CdCl2 - H2O system

    International Nuclear Information System (INIS)

    When studying solubility diagram of 2NaCl + CdSO4 Na2SO4 + CdCl2 - H2O system the earlier unknown compound NaCl · CdSO4 · 5H2O is isolated and identified. Some of its properies (solubility product, thermodynamic properties, refractive index) are studied

  11. A calibration of the triple oxygen isotope fractionation in the SiO2-H2O system and applications to natural samples

    Science.gov (United States)

    Sharp, Z. D.; Gibbons, J. A.; Maltsev, O.; Atudorei, V.; Pack, A.; Sengupta, S.; Shock, E. L.; Knauth, L. P.

    2016-08-01

    It is now recognized that variations in the Δ17O of terrestrial materials resulting from purely mass dependent fractionations, though small, have geological significance. In this study, the δ18O and δ17O values of selected low temperature quartz and silica samples were measured in order to derive the quartz-water fractionation-temperature relationship for the three oxygen isotope system. A 18O/16O quartz-water fractionation equation valid for all temperatures was generated from published high temperature exchange experiments and low temperature empirical estimates and is given by 1000ln αqz-H2O18O /16O = 4.20 (0.11) ×106/T2 - 3.3 (0.2) × 1000/T (T in Kelvins). The equilibrium δ17O-δ18O relationship is given by the equation lnα17O/16O = θlnα18O/16O . The variation of θ with temperature for the quartz-water system was determined empirically using low temperature marine diatoms, microcrystalline quartz and a modern sinter sample. A best fit to the data give the equation θSiO2 - H2O = -(1.85 ± 0.04)/T + 0.5305 , indistinguishable from an earlier theoretical estimate. Application of the quartz-water triple isotope system to low temperature samples provides constraints on both temperature and composition of the water with which the silica last equilibrated. Authigenic quartz crystallization temperatures cluster around 50 °C, which are lower than many previous estimates. The combined δ18O and δ17O values of samples considered to be in equilibrium with ocean or meteoric waters can be used to estimate both formation temperatures and the δ18O value of the meteoric water. Unlike other multiple isotopes systems, such as combined H and O isotopes in cherts, the oxygen source and diagenetic potential for both 17O/16O and 18O/16O ratios are identical, simplifying interpretations from ancient samples.

  12. A calibration of the triple oxygen isotope fractionation in the SiO2-H2O system and applications to natural samples

    Science.gov (United States)

    Sharp, Z. D.; Gibbons, J. A.; Maltsev, O.; Atudorei, V.; Pack, A.; Sengupta, S.; Shock, E. L.; Knauth, L. P.

    2016-08-01

    It is now recognized that variations in the Δ17O of terrestrial materials resulting from purely mass dependent fractionations, though small, have geological significance. In this study, the δ18O and δ17O values of selected low temperature quartz and silica samples were measured in order to derive the quartz-water fractionation-temperature relationship for the three oxygen isotope system. A 18O/16O quartz-water fractionation equation valid for all temperatures was generated from published high temperature exchange experiments and low temperature empirical estimates and is given by 1000ln αqz-H2O 18O /16O =4.20 (0.11) ×106/T2 - 3.3 (0.2) × 1000/T (T in Kelvins). The equilibrium δ17O-δ18O relationship is given by the equation lnα17O/16O = θlnα18O/16O . The variation of θ with temperature for the quartz-water system was determined empirically using low temperature marine diatoms, microcrystalline quartz and a modern sinter sample. A best fit to the data give the equation θSiO2-H2O = -(1.85 ± 0.04)/T + 0.5305 , indistinguishable from an earlier theoretical estimate. Application of the quartz-water triple isotope system to low temperature samples provides constraints on both temperature and composition of the water with which the silica last equilibrated. Authigenic quartz crystallization temperatures cluster around 50 °C, which are lower than many previous estimates. The combined δ18O and δ17O values of samples considered to be in equilibrium with ocean or meteoric waters can be used to estimate both formation temperatures and the δ18O value of the meteoric water. Unlike other multiple isotopes systems, such as combined H and O isotopes in cherts, the oxygen source and diagenetic potential for both 17O/16O and 18O/16O ratios are identical, simplifying interpretations from ancient samples.

  13. Synthesis, crystal structure and thermal stability properties of Co (3-apac) 2 ( H2O ) 2 complex%配合物Co(3-apac)2(H2O)2的合成、结构与热稳定性

    Institute of Scientific and Technical Information of China (English)

    范广; 杨祖培

    2011-01-01

    A mononuclear complex Co(3-apac)2(H2O)2(1) (3-apac;3-aminopyrazine-2-carboxylic acid)with 3-apac as ligand has been prepared from aqueous solution and characterized by elemental analysis,IR,single crystal X-ray diffraction and thermogravime-tric analysis. Crystal data:monoclinic,space group C2/c,α = 7. 8881 (11) (A),b= 12.7560(18) (A),c= 13.686(2) A,α= 90.00°,β= 91.960(2)°,γ=90.00°,V= 1376.29(A)3,Z=4,μ= 1.26 mm-1,F(000)= 616,S=l. 098,final R indices(1>2α-(1) )R1 =0.0311,ωR2 =0. 0929,for all reflections R1 =0.0314,ωR2 =0. 0756(CCDC:828310).%以3-氨基吡嗪-2-羧酸为配体合成了一个钴的单核配合物Co(3-apac)2(H2O)2(1)(3-apac:3 -氨基吡嗪-2-羧酸),并利用元素分析、红外光谱、单晶X-射线衍射以及热重分析对配合物(1)进行了表征.晶体学数据:单斜晶系,C2/c空间群,a=7.8881 (11)(A),b=12.7560(18)(A),c=13.686(2)(A),α=90.00°,β=91.960(2)°,γ=90.00°,V=1376.29(A)3,Z=4,μ=1.26 mm-1,F(000)=616,S=1.098,最终偏离因子[I>20-(I)]R1=0.0284,wR2 =0.0738,对于全部数据R1=0.0314,wR2 =0.0756(CCDC:828310).

  14. Middendorfite, K3Na2Mn5Si12(O,OH)36 · 2H2O, a new mineral species from the Khibiny pluton, Kola Peninsula

    Science.gov (United States)

    Pekov, I. V.; Chukanov, N. V.; Dubinchuk, V. T.; Zadov, A. E.

    2007-12-01

    Middendorfite, a new mineral species, has been found in a hydrothermal assemblage in Hilairite hyperperalkaline pegmatite at the Kirovsky Mine, Mount Kukisvumchorr apatite deposit, Khibiny alkaline pluton, Kola Peninsula, Russia. Microcline, sodalite, cancrisilite, aegirine, calcite, natrolite, fluorite, narsarsukite, labuntsovite-Mn, mangan-neptunite, and donnayite are associated minerals. Middendorfite occurs as rhombshaped lamellar and tabular crystals up to 0.1 × 0.2 × 0.4 mm in size, which are combined in worm-and fanlike segregations up to 1 mm in size. The color is dark to bright orange, with a yellowish streak and vitreous luster. The mineral is transparent. The cleavage (001) is perfect, micalike; the fracture is scaly; flakes are flexible but not elastic. The Mohs hardness is 3 to 3.5. Density is 2.60 g/cm3 (meas.) and 2.65 g/cm3 (calc.). Middendorfite is biaxial (-), α = 1.534, β = 1.562, and γ = 1.563; 2 V (meas.) = 10°. The mineral is pleochroic strongly from yellowish to colorless on X through brown on Y and to deep brown on Z. Optical orientation: X = c. The chemical composition (electron microprobe, H2O determined with Penfield method) is as follows (wt %): 4.55 Na2O, 10.16 K2O, 0.11 CaO, 0.18 MgO, 24.88 MnO, 0.68 FeO, 0.15 ZnO, 0.20 Al2O3, 50.87 SiO2, 0.17 TiO2, 0.23 F, 7.73 H2O; -O=F2-0.10, total is 99.81. The empirical formula calculated on the basis of (Si,Al)12(O,OH,F)36 is K3.04(Na2.07Ca0.03)Σ2.10(Mn4.95Fe0.13Mg0.06Ti0.03Zn0.03)Σ5.20(Si11.94Al0.06)Σ12O27.57(OH)8.26F0.17 · 1.92H2O. The simplified formula is K3Na2Mn5Si12(O,OH)36 · 2H2O. Middenforite is monoclinic, space group: P21/ m or P21. The unit cell dimensions are a = 12.55, b = 5.721, c = 26.86 Å; β = 114.04°, V = 1761 Å3, Z = 2. The strongest lines in the X-ray powder pattern [ d, Å, ( I)( hkl)] are: 12.28(100)(002), 4.31(81)(11overline 4 ), 3.555(62)(301, 212), 3.063(52)(008, 31overline 6 ), 2.840(90)(312, 021, 30overline 9 ), 2.634(88)(21overline 9 , 1.0.overline 1 0

  15. Nickeltalmessite, Ca2Ni(AsO4)2 · 2H2O, a new mineral species of the fairfieldite group, Bou Azzer, Morocco

    Science.gov (United States)

    Chukanov, N. V.; Mukhanova, A. A.; Möckel, S.; Belakovsky, D. I.; Levitskaya, L. A.

    2010-12-01

    Nickeltalmessite, Ca2Ni(AsO4)2 · 2H2O, a new mineral species of the fairfieldite group, has been found in association with annabergite, nickelaustinite, pecoraite, calcite, and a mineral of the chromite-manganochromite series from the dump of the Aït Ahmane Mine, Bou Azzer ore district, Morocco. The new mineral occurs as spheroidal aggregates consisting of split crystals up to 10 × 10 × 20 μm in size. Nickeltalmessite is apple green, with white streak and vitreous luster. The density measured by the volumetric method is 3.72(3) g/cm3; calculated density is 3.74 g/cm3. The new mineral is colorless under a microscope, biaxial, positive: α = 1.715(3), β = 1.720(5), γ = 1.753(3), 2 V meas = 80(10)°, 2 V calc = 60.4. Dispersion is not observed. The infrared spectrum is given. As a result of heating of the mineral in vacuum from 24° up to 500°C, weight loss was 8.03 wt %. The chemical composition (electron microprobe, wt %) is as follows: 25.92 CaO, 1.23 MgO, 1.08 CoO, 13.01 NiO, 52.09 As2O5; 7.8 H2O (determined by the Penfield method); the total is 101.13. The empirical formula calculated on the basis of two AsO4 groups is Ca2.04(Ni0.77Mg0.13Co0.06)Σ0.96 (AsO4)2.00 · 1.91H2O. The strongest reflections in the X-ray powder diffraction pattern [ d, Å ( I, %) ( hkl)] are: 5.05 (27) (001) (100), 3.57 (43) (011), 3.358 (58) (110), 3.202 (100) (020), 3.099 (64) (0 bar 2 1), 2.813 (60), ( bar 1 21), 2.772 (68) (2 bar 1 0), 1.714 (39) ( bar 3 31). The unit-cell dimensions of the triclinic lattice (space group P1 or P) determined from the X-ray powder data are: a = 5.858(7), b = 7.082(12), c = 5.567(6) Å, α = 97.20(4), β = 109.11(5), γ = 109.78(5)°, V = 198.04 Å3, Z = 1. The mineral name emphasizes its chemical composition as a Ni-dominant analogue of talmessite. The type material of nickeltalmessite is deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, registration number 3750/1.

  16. Zn3(OH)2V2O7·2H2O/g-C3N4: A novel composite for efficient photodegradation of methylene blue under visible-light irradiation

    Science.gov (United States)

    Wang, Qizhao; Zheng, Longhui; Bai, Yan; Zhao, Jianjun; Wang, Fangping; Zhang, Rong; Huang, Haohao; Su, Bitao

    2015-08-01

    In this work, we used a facile method to prepare a series of Zn3(OH)2V2O7·2H2O/g-C3N4 composites in a 70 °C water bath for 10 h and characterized them by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET), and photoluminescence (PL). Degradation of methylene blue (MB) and phenol were carried out to evaluate the photocatalytic activities of samples under visible light irradiation. Presence of Zn3(OH)2V2O7·2H2O increased surface areas and promoted the charge separation, exerted great influence on the photocatalytic activity and absorption capacity of g-C3N4. In addition, the synergic effect was explained and a possible photocatalytic mechanism was proposed.

  17. Nuclear magnetic relaxation in the ferrimagnetic chain compound NiCu(C7H6N2O6)(H2O)3·2H2O : three-magnon scattering?

    International Nuclear Information System (INIS)

    Recent proton spin-lattice relaxation-time (T1) measurements on the ferrimagnetic chain compound NiCu(C7H6N2O6)(H2O)3·2H2O are explained by an elaborately modified spin-wave theory. We give strong evidence of the major contribution to 1/T1 being made by the three-magnon scattering rather than the Raman scattering

  18. Air-C2H2-O2 FAAS determination of tin in lead-calcium-tin Alloy%富氧火焰原子吸收光谱法测定铅钙锡合金中的锡

    Institute of Scientific and Technical Information of China (English)

    王嘉盛

    2003-01-01

    采用富氧火焰(Air-C2H2-O2)原子吸收光谱法直接测定铅钙锡合金中0.1%以上的锡.对仪器工作条件、测定体系酸度、共存离子干扰等作了研究.方法准确度高,结果重现性好.

  19. Synthesis, structure, properties and biological behaviour of the complex [RuIV (H2L) Cl2].2H2O (H4L= 1,2-cyclohexanediamminetetraacetic acid).

    Science.gov (United States)

    Vilaplana, Rosario A; Castiñeiras, A; González-Vílchez, Francisco

    2004-01-01

    The highly water-soluble ruthenium complex [Ru(H(2)L)Cl(2)](2)H(2)o, in which H(4)L is the sequestering ligand trans-l, 2-cyclohexanediamminetetraacetic acid (cdta) has been synthesized, structurally characterized and its properties studied. The X-ray crystallographic study shows that the chelating coordinated ligand is tetradentate while the ruthenium environment is octahedral and slightly distorted, with two chloride anions coordinated in cis positions. Potentiometric, conductimetric and infrared studies confirm the presence of two free carboxylic groups, while electronic and voltammetric studies show that the central ion is Ru(IV). The testing of the cytotoxic activity of this complex against three different human cancer cell lines indicates that [Ru(H(2)L)Cl(2)].2H(2)O shows a remarkable and selective antiproliferative effect against the human uterine neck carcinoma HeLa and the malign adenocarcinoma ADLD, showing only a discrete turnout cell inhibition activity against colon adenocarcinoma HT-29. The important antiprotiferative behaviour of complex 1 against the human adenocarcinoma ADLD, indicates that [Ru(H(2)L)Cl(2)].2H(2)O might be considered as potential antineoplastic compound. PMID:18365080

  20. Ferroelectric phase transition in hydrogen-bonded 2-aminopyridine phosphate (NC sub 4 H sub 4 NH sub 2)centre dot H sub 3 PO sub 4

    CERN Document Server

    Czapla, Z; Waskowska, A

    2003-01-01

    A new crystal of 2-aminopyridine phosphate (NC sub 4 H sub 4 NH sub 2)centre dot H sub 3 PO sub 4 has been grown and its x-ray structure and physical properties were studied. At room temperature the crystals are monoclinic, space group C2/c. The flat 2-aminopyridine cations are hydrogen bonded to the anionic [PO sub 4 ] groups. The interesting feature of the crystal structure is the three-dimensional network of hydrogen bonds including, among others, two strong, symmetrical O centre dot centre dot centre dot H, H centre dot centre dot centre dot O interactions with disordered proton locations. Symmetrically related PO sub 4 anions linked through these protons form infinite (PO sub 4) subinfinity chains along the crystal a-axis. The anomalies in the temperature dependence of the electric permittivity showed that the crystal undergoes ferroelectric phase transition at T sub c = 103.5 K. The spontaneous polarization takes place along the crystal a-axis, being parallel to the chains of the hydrogen-bonded PO sub ...

  1. 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.

  2. Nd2(SeO3)2(SeO4) . 2H2O - a mixed-valence compound containing selenium in the oxidation states +IV and +VI

    International Nuclear Information System (INIS)

    Pale pink crystals of Nd2(SeO3)2(SeO4) . 2H2O were synthesized under hydrothermal conditions from H2SeO3 and Nd2O3 at about 200 C. X-ray diffraction on powder and single-crystals revealed that the compound crystallizes with the monoclinic space group C 2/c (a = 12.276(1) A, b = 7.0783(5) A, c = 13.329(1) A, β = 104.276(7) ). The crystal structure of Nd2(SeO3)2(SeO4) . 2H2O is an ordered variant of the corresponding erbium compound. Eight oxygen atoms coordinate the NdIII atom in the shape of a bi-capped trigonal prism. The oxygen atoms are part of pyramidal (SeIVO3)2- groups, (SeVIO4)2- tetrahedra and water molecules. The [NdO8] polyhedra share edges to form chains oriented along [010]. The selenate ions link these chains into layers parallel to (001). The layers are interconnected by the selenite ions into a three-dimensional framework. The dehydration of Nd2(SeO3)2(SeO4) . 2H2O starts at 260 C. The thermal decomposition into Nd2SeO5, SeO2 and O2 at 680 C is followed by further loss of SeO2 leaving cubic Nd2O3. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  3. Thermal, spectroscopic and magnetic properties of the Co xNi1-x(SeO3).2H2O (x = 0, 0.4, 1) phases

    International Nuclear Information System (INIS)

    The Co xNi1-x(SeO3).2H2O (x = 0, 0.4, 1) family of compounds has been hydrothermally synthesized under autogeneous pressure and characterized by elemental analysis, infrared and UV-vis spectroscopies and thermogravimetric and thermodiffractometric techniques. The crystal structure of Co0.4Ni0.6(SeO3).2H2O has been solved from single-crystal X-ray diffraction data. This phase is isostructural with the M(SeO3).2H2O (M = Co and Ni) minerals and crystallizes in the P21/n space group, with a 6.4681(7), b = 8.7816(7), c = 7.5668(7) A, β = 98.927(9) deg and Z = 4. The crystal structure of this series of compounds consists of a three-dimensional framework formed by (SeO3)2- selenite oxoanions and edge-sharing M2O10 dimeric octahedra in which the metallic cations are coordinated by the oxygens belonging to both the selenite groups and water molecules. The diffuse reflectance spectra show the essential characteristics of Co(II) and Ni(II) cations in slightly distorted octahedral environments. The calculated values of the Dq and Racah (B and C) parameters are those habitually found for the 3d7 and 3d8 cations in octahedral coordination. The magnetic measurements indicate the existence of antiferromagnetic interactions in all the compounds. The magnetic exchange pathways involve the metal orbitals from edge-sharing dimeric octahedra and the (SeO3)2- anions which are linked to the M2O10 polyhedra in three dimensions

  4. Synthesis and structure of [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)].H2O: An expanded open-framework amine-bearing uranyl phosphate

    International Nuclear Information System (INIS)

    A new open-framework compound, [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)].H2O, (DUP-1) has been synthesized under mild hydrothermal conditions. The resulting structure consists of diprotonated DABCOH22+ (C6H14N22+) cations and occluded water molecules occupying the channels of a complex uranyl phosphate three-dimensional framework. The anionic lattice contains uranophane-like sheets connected by hydrated pentagonal bipyramidal UO7 units. [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)].H2O possesses five crystallographically unique U centers. U(VI) is present here in both six- and seven-coordinate environments. The DABCOH22+ cations are held within the channels by hydrogen bonds to both two uranyl oxygen atoms and a μ2-O atom. Crystallographic data (193 K, Mo Kα, λ=0.71073 A): DUP-1, monoclinic, P21/n, a=7.017(1) A, b=21.966(4) A, c=17.619(3) A, β=90.198(3)o, Z=4, R(F)=4.76% for 382 parameters with 6615 reflections with I>2σ(I). - Graphical abstract: Packing diagram of the three-dimensional channels and occluded DABCOH22+ and water molecules found in [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)].H2O

  5. A Manganese Coordination Polymer and a Palladium Molecular Compound of 3-Pyridinepropionic acid (HL): [MnL2(H2O)2]∞ and trans-[Pd(HL)2Cl2

    International Nuclear Information System (INIS)

    Three coordination polymers, [ML2(H2O)2] (M = Co (1), Ni (2), Mn (3)), were prepared from metal acetates (M(CH3COO)2·4H2O) and 3-pyridinepropionic acid (HL = (3-py).CH2CH2COOH) by solvent-layer methods. By contrast, a discrete molecular compound, trans-[Pd(HL)2Cl2] (4), was synthesized by replacing benzonitrile (PhCN) ligands in trans-[Pd(PhCN)2Cl2] with HL under microwave-heating conditions. Compounds 1-3 have a 2D framework, and compound 4 contains a square-planar Pd metal

  6. The axial mixing influence on the number stages of countercurrent absorbers in absorbing NH3-CO2-H2O mixture in NaCl-H2O system

    Directory of Open Access Journals (Sweden)

    Vladan Micic

    2010-08-01

    Full Text Available This paper investigates the influence of axial or longitudinal mixing of stages on the number stages in a countercurrent absorber in absorbing vapour-gas mixture of NH3-CO2-H2O in the multicomponent system NaCl-H2O. The number stages in ideal mixing of phases NT and the number of stages which involves axial mixing ND were determined. The authors of this paper conclude that the influence of axial mixing does not affect the number stages in the countercurrent absorber. Otherwise, absorption in this concrete system is practically present in the process of soda ash production.

  7. Mineral-fluid equilibria in the system CaO-MgO-SiO2-H2O-CO2-NaCl and the record of reactive fluid flow in contact metamorphic aureoles

    OpenAIRE

    Wilhelm Heinrich; S.S. Churakov; Matthias Gottschalk;  

    2004-01-01

    Phase equilibria in the system CaO-MgO-SiO2-CO2-H2O-NaCl are calculated to illustrate phase relations in metacarbonates over a wide range of P-T-X[H2O-CO2-NaCl] conditions. Calculations are performed using the equation of state of Duan et al. (1995) for H2O-CO2-NaCl fluids and the internally consistent data set of Gottschalk (1997) for thermodynamic properties of solids. Results are presented in isothermal-isobarical plots showing stable mineral assemblages as a function of fluid composition....

  8. Metal-containing ligands for mixed-metal polymers: novel Cu(II)-Ag(I) mixed-metal coordination polymers generated from [Cu(2-methylpyrazine-5-carboxylate)2(H2O)].3H2O and silver(I) salts.

    Science.gov (United States)

    Dong, Y B; Smith, M D; zur Loye, H C

    2000-05-01

    One Cu(II)-containing ligand and two Cu(II)-Ag(I) mixed-metal coordination polymers have been synthesized. [Cu(2-methylpyrazine-5-carboxylate)2(H2O)].3H2O (1) was obtained as a molecular complex with two uncoordinated nitrogen donors by the reaction of 2-methylpyrazine-5-carboxylate sodium with CuCl(2).2H2O in water. Compound 1 crystallized in the triclinic space group P1, with a = 10.498(2) A, b = 11.000(2) A, c = 8.1424(16) A, alpha = 98.33(3) degrees, beta = 101.83(3) degrees, gamma = 66.68(3) degrees, and Z = 2. Reactions of 1 with silver(I) salts have been studied. Two Cu(II)-Ag(I) mixed-metal coordination polymers, namely, Ag[Cu(2-methylpyrazine-5-carboxylate)2.(H2O)2](BF4) (2) and Ag[Cu(2-methylpyrazine-5-carboxylate)2.(H2O)2](NO3) (3), have been generated by treating 1 with AgBF4 and AgNO3, respectively. Compound 2 crystallized in the monoclinic space group C2/c, with a = 25.827(5) A, b = 9.6430(19) A, c = 7.4525(15) A, beta = 94.74(3) degrees, and Z = 4. Compound 3 also crystallized in the monoclinic space group C2/c, with a = 25.855(5) A, b = 9.782(2) A, c = 7.1201(14) A, beta = 96.90(3) degrees, and Z = 4. The main structural feature in both 2 and 3 is a zigzag Cu(II)-Ag(I) mixed-metal chain, in which the alternating Cu(II) and Ag(I) centers are linked by 2-methylpyrazine-5-carboxylate spacers. The effect of the nitrate counterion was illustrated by compound 3, in which a novel [Ag+...NO3-] coordination chain has been found which acts as the connector to cross-link the one-dimensional zigzag chains into a three-dimensional network. In addition, an identical interchain O-H...O hydrogen bonding system has been found in both 2 and 3 and has been shown to play a significant role in directing the alignment of the one-dimensional mixed-metal polymer chains in the crystalline state. The magnetic susceptibilities of 2 and 3 were measured and found to follow the Curie law (mu eff = 1.85 for 2 and 1.83 for 3). PMID:11428114

  9. Supramolecular assembly based on a heteropolyanion: Synthesis and crystal structure of Na3(H2O)6[Al(OH)6Mo6O18]$\\cdot$2H2O

    Indian Academy of Sciences (India)

    Vaddypally Shivaiah; Samar K Das

    2005-05-01

    Synthesis and structural characterization of a polyoxometalate compound Na3(H2O)6 [Al(OH)6Mo6O18]$\\cdot$2H2O (1) have been described. Compound 1 exhibits three-dimensional network structure in the solid state, which is assembled by Anderson-type heteropolyanions, [Al(OH)6Mo6O18]$_n^{3n-}$, as building blocks sharing sodium cations. 1 possesses ``sinuous" channels occupied by supramolecular water dimers as guests. Anderson anions, sodium-coordinated water and crystal water are additionally involved in an intricate hydrogen-bonding network in the crystal of 1.

  10. Rice husk ash supported FeCl2·2H2O:A mild and highly efficient heterogeneous catalyst for the synthesis of polysubstituted quinolines by Friedländer heteroannulation

    Institute of Scientific and Technical Information of China (English)

    Farhad Shirini; Somayeh Akbari-Dadamahaleh; Ali Mohammad-Khah

    2013-01-01

    Rice husk ash was used as a new, green, and cheap adsorbent for FeCl3. Characterization of the ob-tained reagent showed that rice husk ash supported FeCl2·2H2O was formed. This reagent is effi-cient at catalyzing the synthesis of multisubstituted quinolines by the Friedländer heteroannulation of o-aminoaryl ketones with ketones orβ-diketones under mild reaction conditions. This method-ology allows for the synthesis of a broad range of substituted quinolines in high yields and with excellent regioselectivity in the absence of a solvent.

  11. Ionic-liquid-like local structure in $LiNO_3-Ca(NO_3)_2-H_2O$ as studied by ion and solvent nuclei NMR relaxation

    CERN Document Server

    Matveev, Vladimir V; Lähderanta, Erkki

    2010-01-01

    Relaxation rates in the $13mLiNO_3-6,5mCa(NO_3)_2-H_2O$ ternary system have been measured for nuclei of water ($^1H$ and $^{17}O$), anion ($^{14}N$), and both cations ($^7Li$, $^{43}Ca$). The data analysis reveals the system structure as consisting of two main charged units: [Li(H$_2$O)$_4$]$^+$ and [Ca(NO$_3$)$_4$]$^{2-}$. Thus the system presents inorganic ionic liquid like structure.

  12. Preparation and electrochemical properties of LiFePO4/C nanocomposite using FePO4·2H2O nanoparticles by introduction of Fe3(PO4)2·8H2O at low cost

    International Nuclear Information System (INIS)

    A LiFePO4/C composite was synthesized by a simple solid-state reaction method using stearic acid as reductive agent and carbon source and nano-sized FePO4·2H2O as precursor which was prepared from intermediate Fe3(PO4)2·8H2O using industrial FeSO4·7H2O and industrial NH4H2PO4 at a low cost. The structure, morphology and electrochemical performance of LiFePO4/C were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge–discharge tests, cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that the LiFePO4/C has an olivine-type structure with nano-size and exhibits excellent electrochemical properties. The discharge capacities are 159 mAh g−1, 148 mAh g−1 and 113 mAh g−1 at 0.1 C, 1 C and 10 C, respectively. Furthermore, the capacity retention rate is higher than 99% after 100 cycles at 1 C and 10 C. The excellent electrochemical performances of LiFePO4/C composite should be attributed to spherical nanoparticles as well as less impurity in FePO4·2H2O precursor

  13. Monitoring dehydration of the organic-inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and Raman studies

    Science.gov (United States)

    Hajlaoui, S.; Chaabane, I.; Guidara, K.; Bulou, A.

    2016-07-01

    In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356-376 (T1) K and at 393 K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800 cm- 1 covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(Snsbnd O) + νs(Snsbnd Cl)), based on an order-disorder model allowed us to obtain information relative to the activation energy and correlation length.

  14. Effect of FeSO4.7H2O and SnCl2.2H2O added as Chromium (VI Reducers in Ordinary Portland Cement

    Directory of Open Access Journals (Sweden)

    Devesh K. Sharma

    2015-03-01

    Full Text Available The paper compared the effect of additives such as FeSO4.2H2O and SnCl2.2H2O on reduction of water soluble Cr(VI, in ordinary Portland cement (43 grades. The determination of water soluble Cr(VI from cement samples was precisely conducted by DPC-Spectrophotometer technique. The compressive strength testing of the cement mortar samples was carried out. In addition, hydration properties of cement paste (with and without additives are reported in this paper. Hydration products were also studied in detail by TGA, SEM and XRD. Tin chloride was found to be the most efficient additive for reducing Cr(VI in cement. XRD confirmed two phases such as monocarbonate and Friedel’s salt (at 2θ = 11.5 were formed during cement hydration in the presence of tin chloride but not confirmed the presence of calcium hydroxo-stannate. These studies showed significant retardation in early days hydration.

  15. Crystal structure, dielectric properties and molecular motions of molecules in thiazolium halometalates(III): (C3H4NS)6M4Br18·2H2O (M = Sb, Bi)

    Science.gov (United States)

    Piecha, A.; Jakubas, R.; Kinzhybalo, V.; Medycki, W.

    2012-04-01

    Two thiazolium analogs, (C3H4NS)6Sb4Br18·2H2O (TBA) and (C3H4NS)6Bi4Br18·2H2O (TBB), have been synthesized and structurally characterized. The compounds appeared to be isomorphous and crystallize in the triclinic symmetry, space group P1¯ (at 100 K). These ionic complexes are built up of thiazolium cations, centrosymmetric [M4Br18]6- anions (M = Sb, Bi) and water molecules. One of three independent thiazolium cations was found to be disordered (two-site model). The cations are hydrogen bonded to [M4Br18]6- moieties and water molecules. The water molecule (Ow) acts as a donor of the O-H⋯Br and an acceptor of the N-H⋯O types of hydrogen bonds. The dielectric dispersion studies disclosed a low frequency relaxation process characterized by a significant slowing down of two independent dielectric relaxators. The dielectric behavior was explained by the motion of thiazolium cations and water molecules The molecular motions of the thiazolium and water molecules were studied by means of the 1H NMR spin-lattice relaxation time (T1) measurements.

  16. Monitoring dehydration of the organic-inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and Raman studies.

    Science.gov (United States)

    Hajlaoui, S; Chaabane, I; Guidara, K; Bulou, A

    2016-07-01

    In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356-376 (T1) K and at 393K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800cm(-1) covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(SnO)+νs(SnCl)), based on an order-disorder model allowed us to obtain information relative to the activation energy and correlation length. PMID:27070530

  17. Thermodynamic properties of scorodite and parascorodite (FeAsO4 center dot 2H(2)O), kankite (FeAsO4 center dot 3.5H(2)O), and FeAsO4

    Czech Academy of Sciences Publication Activity Database

    Majzlan, J.; Drahota, P.; Filippi, Michal; Grevel, K.-D.; Kahl, W.-A.; Plášil, J.; Boerio-Goates, J.; Woodfield, B. F.

    117/118, April (2012), s. 47-56. ISSN 0304-386X Institutional research plan: CEZ:AV0Z30130516 Keywords : scorodite * ferric arsenates * formation enthalpy * entropy * solubility Subject RIV: DD - Geochemistry Impact factor: 2.169, year: 2012

  18. Synthesis and Crystal Structure of an Organic-inorganic Complex [Hg(DMSO)2(H2O)]2 [GeW12O40]·DMSO·H2O

    Institute of Scientific and Technical Information of China (English)

    Jing Ping WANG; Xiao Di DU; Xian Ying DUAN; Jing Yang NIU

    2006-01-01

    An organic-inorganic mercury coordination compound [Hg(DMSO)2(H2O)]2 [GeW12O40]·DMSO·H2O(DMSO =dimethyl sulfoxide) has been synthesized and characterized by IR, UV spectra, elemental analysis, TG-DTA and X-ray single-crystal diffraction. Structural analysis revealed that in the title compound, the mercury is three-coordinated to show the distorted trigonal cone geometry, and depending on the electrostatic interaction to connect the polyanion [α-GeW12O40]4-. TG-DTA study manifests the decomposition temperature of the polyanion framework in the title compound is 513.5℃, which is much higher than that of the anion framework. It means that the formation of the organic-inorganic mercury coordination compound made the polyanion [α-GeW12O40]4- to be more stable.

  19. Hydrothermal Synthesis and Crystal Structure of Zinc(Ⅱ) Dinicotinate Complex [Zn(nic)2(H2O)4](nic=nicotinic acid):A Three-dimensional Hydrogen-bond Network

    Institute of Scientific and Technical Information of China (English)

    MAO Hong-yan; ZHANG Zong-pei; ZHANG Hong-yun; XU Chen; WANG En-bo; WU Qing-an; ZHU Yu

    2004-01-01

    @@ Introduction Nicotinic acid and its transition-metal comple-xes have become increasingly important due to their potential applications as cosmetics or medicines with antitumor, antibacterial and antifungal activities, and the activity in the maintenance of normal glucose metabolism[1-3], etc. A major research effort has been made to generate such materials and to study their biological activity[4-9]. But few of the previous works have directed towards the structure investigation of these metal complexes[6-9]. So, in this report we aim at testing the effect of hydrothermal synthesis on the formation of the crystal structures of crystalline [Zn(nic)2(H2O)4 ](nic=nicotinic acid).

  20. DNA-Binding Study of Tetraaqua-bis(p-nitrobenzoatocobalt(II Dihydrate Complex: [Co(H2O4(p-NO2C6H4COO2]·2H2O

    Directory of Open Access Journals (Sweden)

    Hacali Necefoglu

    2007-06-01

    Full Text Available The interaction of [Co(H2O4(p-NO2C6H4COO2]. 2H2O with sheep genomicDNA has been investigated by spectroscopic studies and electrophoresis measurements.The interaction between cobalt(II p-nitrobenzoate and DNA has been followed by gelelectrophoresis while the concentration of the complex was increased from 0 to 14 mM.The spectroscopic study and electrophoretic experiments support the fact that the complexbinds to DNA by intercalation via p-nitrobenzoate into the base pairs of DNA. Themobility of the bands decreased as the concentration of complex was increased, indicatingthat there was increase in interaction between the metal ion and DNA.

  1. Synthesis and Structure of an Interlock Network Frame of Cobalt( Ⅱ ) Coordination Polymer {[Co(azpy)2(NCS)2] · 1/4EtOH · 1/2H2O}n (azpy = 4,4' -Azobispyridine)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A compound {[Co(azpy)2(NCS)2]·1/4EtOH·1/2H2O}n(1), where azpy=4,4'- azo-bispyridine, was synthesized and characterized by means of IR, TGA-DTA, magnetic susceptibility and X-ray single crystal diffraction. It consists of two independent sets of fully interlocked two-dimensional networks with the dihedral angle 61. 7°, organized in parallel stacks of the sheets which are made of edge-shared [Co(Ⅱ)]4 squares separated by 0. 906 2 nm, and defined size rhombic channels. The thermal gravimetric analysis indicates that the framework is stable up to 198 C. The variable-temperature magnetic susceptibility measurements indicated that there is a weak antiferromagnetic interaction between the cobalt(Ⅱ) ions in the complex (1).

  2. Synthesis, crystal structure, and characterization of two-dimensional coordination polymers of three heavy rare-earth elements: [RE(5-Nip)(5-HNip)(H2O)2](H2O)2 (RE = Y, Ho, Er)

    International Nuclear Information System (INIS)

    Three new coordination polymers, [RE(5-Nip)(5-HNip)(H2O)2] · 2H2O (RE = Y (I), Ho (II), and Er (III)) were synthesized by hydrothermal reactions of lanthanide nitrates with 5-nitroisophthalic acid (H2Nip), and characterized by IR spectra, elemental analysis, and single-crystal X-ray diffraction. X-ray diffraction studies suggest that all the two-dimensional 5-nitroisophthalic complexes crystallize in the P1-bar space group and are isomorphic. The two-dimensional layer-like structures are constructed by the lanthanide ions bridged by 5-Nip2- ligands, and the layers further packed into 3D complexes through hydrogen bonds and two kinds of π-π stacking interactions. These complexes exhibit high stabilities up to 465 (1), 518 (2), and 528 deg C (3), respectively

  3. The first 3D malonate bridged copper [Cu(O2C–CH2–CO2H)2·2H2O]: Structure, properties and electronic structure

    International Nuclear Information System (INIS)

    A new inorganic-organic compound [Cu(O2C–CH2–CO2H)2·2H2O] ([Cumal]) was hydrothermally synthesized and characterized by IR spectroscopy, thermal analysis and single crystal X-ray diffraction. [Cumal] is the first three-dimensional compound existing in the system Cu(II)–malonic acid–H2O. Its framework is built up through carboxyl bridged copper where CuO6 octahedra are elongated with an almost D4h symmetry (4+2) due to the Jahn–Teller effect. The magnetic properties were studied by measuring its magnetic susceptibility in the temperature range of 2–300 K indicating the existence of weak ferromagnetic interactions. The electronic structure of [Cumal] was calculated within the density functional theory (DFT) framework. Structural features are well reproduced using DFT structural optimizations and the optical spectra, calculated within the dielectric formalism, explain very well the light blue colour of the compound. It is shown that a GGA+U approach with a Ueff value of about 6 eV is necessary for a better correlation with the experiment. - Graphical abstract: [Cu(O2C–CH2–CO2H)2·2H2O]: the first 3D hybrid organic–inorganic compound built up carboxyl groups. The network presents a diamond-like structure achieved via carboxyl. Highlights: ► A new organic–inorganic material with an unprecedented topology is synthesized. ► Crystallographic structure is determined using single crystal X-ray diffraction. ► Electronic structure is obtained from DFT, GGA+U calculation. ► Framework can be described as formed from CuC4 tetrahedron sharing four corners. ► This structure can be classified as an extended diamond structure.

  4. The effect of carbonic anhydrase on the kinetics and equilibrium of the oxygen isotope exchange in the CO2-H2O system: Implications for δ18O vital effects in biogenic carbonates

    Science.gov (United States)

    Uchikawa, Joji; Zeebe, Richard E.

    2012-10-01

    Interpretations of the primary paleoceanographic information recorded in stable oxygen isotope values (δ18O) of biogenic CaCO3 can be obscured by disequilibrium effects. CaCO3 is often depleted in 18O relative to the δ18O values expected for precipitation in thermodynamic equilibrium with ambient seawater as a result of vital effects. Vital effects in δ18O have been explained in terms of the influence of fluid pH on the overall δ18O of the sum of dissolved inorganic carbon (DIC) species (often referred to as "pH model") and in terms of 18O depletion as a result of the kinetic effects associated with CO2 hydration (CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+) and CO2 hydroxylation (CO2 + OH- ↔ HCO3-) in the calcification sites (so-called "kinetic model"). This study addresses the potential role of an enzyme, carbonic anhydrase (CA), that catalyzes inter-conversion of CO2 and HCO3- in relation to the underlying mechanism of vital effects. We performed quantitative inorganic carbonate precipitation experiments in order to examine the changes in 18O equilibration rate as a function of CA concentration. Experiments were performed at pH 8.3 and 8.9. These pH values are comparable to the average surface ocean pH and elevated pH levels observed in the calcification sites of some coral and foraminiferal species, respectively. The rate of uncatalyzed 18O exchange in the CO2-H2O system is governed by the pH-dependent DIC speciation and the kinetic rate constant for CO2 hydration and hydroxylation, which can be summarized by a simple mathematical expression. The results from control experiments (no CA addition) are in agreement with this expression. The results from control experiments also suggest that the most recently published kinetic rate constant for CO2 hydroxylation has been overestimated. When CA is present, the 18O equilibration process is greatly enhanced at both pH levels due to the catalysis of CO2 hydration by the enzyme. For example, the time required for 18O

  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

    2016-06-01

    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.

  6. Effect of the precursor layer on properties of nanoscopic powders formed by thermally induced decomposition of FeC2O4·2H2O in air

    International Nuclear Information System (INIS)

    Effect of sample layer on properties of iron(III) oxide nanoparticles prepared by isothermal decomposition of the FeC2O4·2H2O powder has been studied in static air conditions at reaction temperature of 175 grad C using 57Fe Moessbauer spectroscopy, XRD, TEM, and BET surface area measurements. In-field Moessbauer spectroscopy was applied for distinguishing and quantification of amorphous and nanocrystalline (γ-Fe2O3, [α-Fe2O3) iron oxides. Independently on the layer thickness, amorphous iron(III) oxide nanoparticles (1-2 nm) are produced as the primary decomposition product. Above a critical thickness, amorphous nanoparticles crystallize to nanocrystalline superparamagnetic maghemite (γ-Fe2O3, 5-8 nm), which process is accompanied by an increase of the sample temperature. With increasing thickness of ferrous oxalate layer, the crystallization of primarily formed amorphous Fe2O3 nanoparticles starts later with longer duration. The maghemite samples prepared above a critical weight reveal contrast properties suitable for application in magnetic resonance imaging. Below a critical thickness, however, the crystallization process proceeds very slowly without any indications of an increase of sample temperature. Hematite with a large surface area and excellent catalytic properties was clearly identified as the only crystallization product. The possibility of unique monitoring of the crystallization of amorphous phase through an increase of the sample temperature is demonstrated on other solid state reactions including thermal conversions of iron(II) acetate and Prussian Blue. (authors)

  7. Hydrothermal Assembly and Structural Characterization of a Novel 3D Coordination Polymer: [Cd2Zn(BTC)2(H2O)4]n·2nH2O

    Institute of Scientific and Technical Information of China (English)

    陈建新; 刘世雄

    2005-01-01

    A hydrothermal reaction of 1,3,5-benzene-tricarboxylic acid (H3BTC) with cad- mium acetate, zinc acetate and pyridine led to the formation of pink crystals of [Cd2Zn(BTC)2- (H2O)4]n·2nH2O 1. Single-crystal X-ray diffraction analysis has revealed that 1 (Cd2ZnC18H18O18) crystallizes in the monoclinic system, space group C2/c with a = 19.4328(7), b = 7.1420(3), c = 18.0426(5)(A), β = 118.035(1)o, V = 2210.3(1) (A)3, Mr = 812.49, Dc = 2.442 g/cm3, Z = 4, μ(MoKα) = 3.081 mm-1 and F(000) =1584. A total of 10735 reflections were collected, of which 2544 were unique. The structure was refined to R = 0.0200 and wR = 0.0603 for 2388 observed reflections with I>2σ(I). The crystal structure consists of cadmium(II)/zinc(II) carboxylates of BTC as well as coordination and discrete water molecules. Extension of the coordination geometry around three metal centers (Cd(1), Cd(2) and Zn(1)), two BTC3- ligands and four coordinated water molecules generates a three-dimensional coordination polymer.

  8. Synthesis and X-ray structural investigation of K8[(UO2)2(C2O4)2(SeO4)4] . 2H2O

    International Nuclear Information System (INIS)

    Single crystals of the compound K8[(UO2)2(C2O4)2(SeO4)4] . 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 14.9290(4) A, b = 7.2800(2) A, c = 15.3165(4) A, β = 109.188(1)o, V = 1572.17(7) A3, space group P21/n, Z = 2, and R = 0.0297. The uranium-containing structural units of crystals I are dimers of the composition [(UO 2)2(C2O4)2(SeO4)4]8-, which belong to the crystal-chemical group AB01B2M1 (A = UO22+, B01 = C2O42-, B2 = SeO42-, M1 = SeO42-) of the uranyl complexes. The [(UO2)2(C2O4)2(SeO4)4]8- dimers are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere potassium cations.

  9. Optical emission spectroscopy study of premixed C2H4/O2 and C2H4/C2H2/O2 flames for diamond growth with and without CO2 laser excitation

    Science.gov (United States)

    He, X. N.; Gebre, T.; Shen, X. K.; Xie, Z. Q.; Zhou, Y. S.; Lu, Y. F.

    2010-02-01

    Optical emission spectroscopy (OES) measurements were carried out to study premixed C2H4/O2 and C2H4/C2H2/O2 combustion flame for diamond deposition with and without a CO2 laser excitation. Strong emissions from radicals C2 and CH were observed in the visible range in all the OES spectra acquired. By adding a continuous-wave CO2 laser to irradiate the flame at a wavelength of 10.591 μm, the common CO2 laser wavelength, it was discovered that the emission intensities of the C2 and CH radicals were increased due to the laser beam induced excitation. OES measurements of the C2 and CH radicals were performed using different gas combinations and laser powers. The rotational temperatures in the flame were determined by analyzing the spectra of the R-branch of the A2Δ-->X2Π (0, 0) electronic transition near 430 nm (CH band head). Information obtained from the OES spectra, including the emission intensities of the C2 and CH radicals, the intensity ratios, and the rotational temperatures, was integrated into the study of diamond deposition on tungsten carbide substrates for mechanism analysis of the laser induced vibrational excitation and laser-assisted diamond deposition.

  10. Two-Step Photon Absorption Driving the Chemical Reaction in the Model Ruthenium Nitrosyl System [Ru(py)4Cl(NO)](PF6)2·(1)/2H2O.

    Science.gov (United States)

    Khadeeva, Liya; Kaszub, Wawrzyniec; Lorenc, Maciej; Malfant, Isabelle; Buron-Le Cointe, Marylise

    2016-05-01

    Various systems containing the [ML5NO] molecule, where M = Fe, Ru, ... and L = F, Cl, ..., exhibit switching under continuous light (CW) irradiation between the ground-state nitrosyl (GS), isonitrosyl (MSI), and side-on (MSII) configurations. The metastable populations, however, are often limited to a few percent. The [Ru(py)4Cl(NO)](PF6)2·(1)/2H2O system is thus a remarkable model compound as the GS to MSI transformation is nearly complete in a single crystal. A predominant two-step photon absorption process during GS to MSI switching under blue light is revealed by visible absorption spectroscopy, although a low concentration of the transient species hinders the determination of this process by the structural signature. During the depopulation of MSI, both two-step and direct processes are evidenced under red CW irradiation. Different intermediate visible spectra revealing transient species during GS to MSI and the reverse photochemical processes are discussed in relation to MSII properties. PMID:27054377

  11. X-ray structure of W(CO)3(PPri3)2(H2O)·THF. Isotopic exchange between H2O and η2-D2 ligands and their competitive binding to tungsten

    International Nuclear Information System (INIS)

    Reactions of water with M(CO)3(PR3)2 and M(CO)3(PR3)2(η2-H2) [M = Mo, W; R = Cy (cyclohexyl), i-Pr] have been studied in various organic solvents. Infrared studied of the products showed v(OH) modes at widely varying positions, but no clear evidence for oxidative addition of water was found. The aquo complex W(CO)3(P-i-Pr3)2(H2O)·THF was isolated from THF and structurally characterized. A long W-O distance of 2.32 angstrom was observed for the reversibly bound H2O ligand, which also undergoes hydrogen bonding interactions with both lattice THF and a CO on an adjacent molecule. Water was found to instantaneously displace the dihydrogen ligand in M(CO)3(PR3)2(η2-H2) in THF solution to give aquo complexes, but in hexane H2 remained bound under H2 atmosphere. NMR spectra of the aquo complexes showed rapid exchange between free and coordinated water at 298 K. Isotopic exchange of W(CO)3(P-i-Pr3)2(η2-D2) with H2O under D2 atmosphere took place in THF or toluene giving W(CO)3(P-i-Pr3)2(D2O)

  12. Adsorption kinetic regime of cocrystallization. The system ZnC2O4x2H2O-54MnC2O4x2H20

    International Nuclear Information System (INIS)

    The ZnC2O4x2H2O finely divided deposit surface properties have been investigated by the methods of electron microscopy, gas adsorption and isotopic exchange in 65Zn 54Mn adsorption from aqueous solutions with Mn2+ initial concentration of 4x10-6 - 5x10-4 mol/l has been studied using the same deposit. Characteristic frequencies of Zn2+ and Mn2+ transitions between layers, zinc and manganese oxalates masses in the first and second layers and local coefficients of cocrystallization of manganese and zinc oxalates in near-surface layers (lambda=0.38+-0.05 and lambda2=0.17+-0.04) have been calculated using representation on successive Zn2+ and Mn2+ transition to three near-surface monolayers and on reverse translation motion. A formula for the connection of lambda sub(γ) coefficients ( is a number of the surface layer) with a layer-to-surface distance has been depived. A possibility of the forecast of a dependence of effective cocrystallization coefficient of impurity with growing crystals on crystal growth rate has been revealed

  13. Short Wave upwelling Radiative Flux (SWupRF) within NIR range for the selected greenhouse wavelength bands of O2, H2O, CO2 and CH4 by Argus 1000 along with GENSPECT line by line radiative transfer model

    CERN Document Server

    Siddiqui, Rehan; Salem, Naif Al; Quine, Brendan M

    2016-01-01

    This new study develops an algorithm for Short Wave upwelling Radiative Flux (SWupRF) for the spectral variations within near infrared (NIR) from 1100 to 1700 nm wavelength band based on remote sensing data set of Argus 1000 micro-spectrometer observations. We calculate the SWupRF by investigating the total radiative flux due to O2, H2O, CO2 and CH4 and also by the individual gas within the selected wavelength bands of interest. A GENSPECT synthetic line by line radiative transfer model is applied to perform radiative transfer simulations to calculate the radiative flux by varying surface albedo, mixing ratios of the selected greenhouse gases, surface temperature, solar sun and zenith angles with different latitude and longitude of the instrument. Finally, the SWupRFsyn estimated from GENSPECT was compared with SWupRFobs from Argus 1000 over a period of four years (2009 and 2013) covering all seasons. We calculate and compare both the synthetic and real measured observed data set. The synthetic model gives SW...

  14. Structure and Two-dimensional Correlation Infrared Spectroscopy Study of a New One-dimensional Chain Compound:(4,4'-Hbpy)3[NaMo8O26] (4,4'-bpy)2(H2O)4 (bpy = Bipydine)

    Institute of Scientific and Technical Information of China (English)

    CHEN Yi-Ping; ZHANG Han-Hui; KE Da-Mei; SHEN Xiao-Min; HUANG Chang-Cang; SUN Rui-Qing

    2005-01-01

    A novel compound, (4,4'-Hbpy)3[NaMo8O26](4,4'-bpy)2(H2O)4 1 (bpy = bipydine),was synthesized by the hydrothermal method. Single-crystal X-ray diffraction shows that compound 1 belongs to the monoclinic system, space group C2/m with a = 19.1921(5), b = 18.6931(6), c = 9.3821 (3) (A), β = 104.8020(11)°, V = 3254.22(17) (A)3, C50H51Mo8N10NaO30, Mr = 2062.52, Z = 2,F(000) = 2016,μ = 1.591 mm- 1 and Dc = 2.105 g/cm3. The final R = 0.0283 and wR = 0.0912 for 3118 observed reflections (I > 2σ(Ⅰ)). Compound 1 contains the β-[Mo8O26]4- anion, sodium ion, 4,4'-bpy and lattice crystalline water molecules. The β-[Mo8O26] units link the sodium ion to form a chain structure. The infinitechains of [Na(Mo8O26)]3- blocks are surrounded by protonized 4,4'-bpy cations,4,4'-bpy and lattice crystalline water molecules. The 2D-IR correlation spectroscopy study indicates that the stretching vibrations of Mo=O occur more preferentially due to the thermal effect. The TGA analysis shows that compound 1 has high thermal stability.

  15. Bulk modulus of basic sodalite, Na8[AlSiO4]6(OH)2·2H2O, a possible zeolitic precursor in coal-fly-ash-based geopolymers

    KAUST Repository

    Oh, Jae Eun

    2011-01-01

    Synthetic basic sodalite, Na8[AlSiO4] 6(OH)2•2H2O, cubic, P43n, (also known as hydroxysodalite hydrate) was prepared by the alkaline activation of amorphous aluminosilicate glass, obtained from the phase separation of Class F fly ash. The sample was subjected to a process similar to geopolymerization, using high concentrations of a NaOH solution at 90 °C for 24 hours. Basic sodalite was chosen as a representative analogue of the zeolite precursor existing in Na-based Class F fly ash geopolymers. To determine its bulk modulus, high-pressure synchrotron X-ray powder diffraction was applied using a diamond anvil cell (DAC) up to a pressure of 4.5 GPa. A curve-fit with a truncated third-order Birch-Murnaghan equation of state with a fixed K\\'o = 4 to pressure-normalized volume data yielded the isothermal bulk modulus, K o = 43 ± 4 GPa, indicating that basic sodalite is more compressible than sodalite, possibly due to a difference in interactions between the framework host and the guest molecules. © 2010 Elsevier Ltd.

  16. Low-Temperature Heat Capacities and Thermodynamic Properties of Hydrated Nickel L-Threonate Ni(C4H7O5)2·2H2O(s)

    Institute of Scientific and Technical Information of China (English)

    DI You-Ying; TAN Zhi-Cheng; GAO Sheng-Li; CHEN San-Ping; SUN Li-Xian

    2007-01-01

    Low-temperature heat capacities of the compound Ni(C4H7O5)2·2H2O(s) have been measured with an automated adiabatic calorimeter. A thermal decomposition or dehydration occurred in 350-369 K. The temperature,enthalpy and entropy of the dehydration were determined to be (368.141+-0.095)K,(18.809+-0.088)kJ·mol-1 and (51.093+-0.239)J·K-1·mol-1 respertively.The exterimental values of the molar heat capacities in the temperature regions of 78-350 and 368-390 K were fitted to two polynomial equations of heat capacities (Cp,m)with the reduced temperatures (X), [X=f(T)], by a least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound were calculated on the basis of the fitted polynomials. The smoothed values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were tabulated with an interval of 5 K.

  17. Heat capacity and thermodynamical properties of the crystal of [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE=Nd,Eu,Dy)

    Institute of Scientific and Technical Information of China (English)

    WU XinMin; LI Wei; TAN ZhiCheng; QU SongSheng

    2009-01-01

    Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry.However,they have rarely been reported.In this work,a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium,and their thermodynamical data,including the heat capacity in low temperature range and the standard enthalpy of formation,were determined.These complexes were identified to be [RE2(Glu)2(H2O)8](ClO4)4.H2O (RE=Nd,Eu,Dy) by using thermogravimetric analysis (TG),differential thermal analysis (DTA),and chemical and elementary analyses.Their purity has been determined.No melting points were observed for all the three complexes.The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 370 K.Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found.The temperature,enthalpy change and entropy change of the decomposition processes of the three complexes were calculated.The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting.The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at 298.15 K.

  18. Preparation, crystal structure, and characterization of an inorganic-organic hybrid polyoxoniobate [Cu(en)2]3[Cu(en)2(H2O)]1.5[K0.5Nb24O72H14.5]2.25H2O

    Indian Academy of Sciences (India)

    Jing-Ping Wang; Hong-Yu Niu; Jing-Yang Niu

    2008-05-01

    An inorganic-organic hybrid polyoxoniobate compound [Cu(en)2]3[Cu(en)2(H2O)]1.5 [K0.5Nb24O72H14.5]2.25H2O (1) was synthesized by reaction of K7HNb6O19.13H2O, Cu(CH3COOH)2.H2O and en (ethylenediamine) in aqueous solution and characterized by IR, ESR spectroscopy and singlecrystal X-ray diffraction method. Structure analysis indicates that compound 1 consists of a new type polyoxoniobate anion [K0.5Nb24O72H14.5]9-, three [Cu(en)2]2+, one point five [Cu(en)2(H2O)]2+, and two point two five crystal water molecules. The structure contains N-H$\\cdots$O hydrogen bonds between the coordinated ethylenediamine and the polyniobate-anion. The whole molecule possesses the 3 symmetry.

  19. A novel amido-pyrophosphate Mn(II) chelate complex with the synthetic ligand O{P(O)[NHC(CH3)3]2}2 (L): [Mn(L)2{OC(H)N(CH3)2}2]Cl2·2H2O.

    Science.gov (United States)

    Tarahhomi, Atekeh; Pourayoubi, Mehrdad; Fejfarová, Karla; Dušek, Michal

    2013-03-01

    The title complex, trans-bis(dimethylformamide-κO)bis{N,N'-N'',N'''-tetra-tert-butyl[oxybis(phosphonic diamide-κO)]}manganese(II) dichloride dihydrate, [Mn(C16H40N4O3P2)2(C3H7NO)2]Cl2·2H2O, is the first example of a bis-chelate amido-pyrophosphate (pyrophosphoramide) complex containing an O[P(O)(NH)2]2 fragment. Its asymmetric unit contains half of the complex dication, one chloride anion and one water molecule. The Mn(II) atom, located on an inversion centre, is octahedrally coordinated, with a slight elongation towards the monodentate dimethylformamide ligand. Structural features of the title complex, such as the P=O bond lengths and the planarity of the chelate ring, are compared with those of previously reported complexes with six-membered chelates involving the fragments C(O)NHP(O), (X)NP(O) [X = C(O), C(S), S(O)2 and P(O)] and O[P(O)(N)2]2. This analysis shows that the six-membered chelate rings are less puckered in pyrophosphoramide complexes containing a P(O)OP(O) skeleton, such as the title compound. The extended structure of the title complex involves a linear aggregate mediated by N-H...O and N-H...Cl hydrogen bonds, in which the chloride anion is an acceptor in two additional O-H...Cl hydrogen bonds. PMID:23459342

  20. Experimental investigations of the reaction path in the MgO-CO2-H2O system in solutions with various ionic strengths, and their applications to nuclear waste isolation

    International Nuclear Information System (INIS)

    The reaction path in the MgO-CO2-H2O system at ambient temperatures and atmospheric CO2 partial pressure(s), especially in high-ionic-strength brines, is of both geological interest and practical significance. Its practical importance lies mainly in the field of nuclear waste isolation. In the USA, industrial-grade MgO, consisting mainly of the mineral periclase, is the only engineered barrier certified by the Environmental Protection Agency (EPA) for emplacement in the Waste Isolation Pilot Plant (WIPP) for defense-related transuranic waste. The German Asse repository will employ a Mg(OH)2-based engineered barrier consisting mainly of the mineral brucite. Therefore, the reaction of periclase or brucite with carbonated brines with high-ionic-strength is an important process likely to occur in nuclear waste repositories in salt formations where bulk MgO or Mg(OH)2 will be employed as an engineered barrier. The reaction path in the system MgO-CO2-H2O in solutions with a wide range of ionic strengths was investigated experimentally in this study. The experimental results at ambient laboratory temperature and ambient laboratory atmospheric CO2 partial pressure demonstrate that hydromagnesite (5424) (Mg5(CO3)4(OH)2 . 4H2O) forms during the carbonation of brucite in a series of solutions with different ionic strengths. In Na-Mg-Cl-dominated brines such as Generic Weep Brine (GWB), a synthetic WIPP Salado Formation brine, Mg chloride hydroxide hydrate (Mg3(OH)5Cl . 4H2O) also forms in addition to hydromagnesite (5424). The observation of nesquehonite (MgCO3 . H2O) and subsequent appearance of hydromagnesite (5424) in the experiments in a Na-Cl-dominated brine (ERDA-6) at room temperature and PCO2=5x10-2 atm allows estimation of the equilibrium constant (log K) for the following reaction: Mg5(CO3)4(OH)2.4H2O+CO2(g)+10H2O=5MgCO3.3H2O as ∼2.5 at 25 deg. C. The log K for the above reaction at 5 deg. C is calculated to be ∼4.0 by using the Van't Hoff equation. By using

  1. Structural characterization, molecular dynamics, dielectric and spectroscopic properties of tetrakis(pyrazolium) bis(μ 2-bromo-tetrabromobismuthate(III)) dihydrate, [C 3N 2H 5] 4[Bi 2Br 10]·2H 2O

    Science.gov (United States)

    Piecha, A.; Kinzhybalo, V.; Jakubas, R.; Baran, J.; Medycki, W.

    2007-11-01

    The structure of [C 3N 2H 5] 4[Bi 2Br 10]·2H 2O, (PBB) was determined by single crystal X-ray diffraction at 100 K. It crystallizes in the monoclinic space group C2/ m, with a = 12.992(4) Å, b = 16.326(5) Å, c = 8.255(3) Å, β = 108.56°(3), V = 1659.9(9) Å 3 and Z = 2. The structure consists of discrete binuclear [Bi 2Br 10] 4- anions, ordered pyrazolium cations and water molecules. The crystal packing is governed by strong N-H⋯O and weak O-H⋯Br hydrogen bonds. A sequence of structural phase transitions in PBB was established on the basis of differential scanning calorimetry and dilatometric studies. Two reversible first-order phase transitions were found: (I → II) at 381/371 K (on heating/cooling) and (II → III) at 348/338 K. Dielectric response near both phase transitions is characteristic of crystals with the "plastic-like" phases. Over the phase III a low frequency dielectric relaxator is disclosed. The possible molecular motions in the PBB compound are characterized by the 1H NMR studies. The infrared spectra of polycrystalline compound in the temperature range 300-380 K are reported for the region 4000-400 cm -1. The observed spectral changes through the structural phase transition III → II are attributed to an onset of motion both of the pyrazolium cations and water molecules.

  2. Structure, phase transitions and ionic conductivity of K3NdSi6O15.xH2O. I. α-K3NdSi6O15.2H2O and its polymorphs

    International Nuclear Information System (INIS)

    Hydrothermally grown crystals of α-K3NdSi6O15.2H2O, potassium neodymium silicate, have been studied by single-crystal X-ray methods. The compound crystallizes in space group Pbam, contains four formula units per unit cell and has lattice constants a = 16.008 (2), b = 15.004 (2) and c = 7.2794 (7) A, giving a calculated density of 2.683 Mg m-3. Refinement was carried out with 2161 independent structure factors to a residual, R(F), of 0.0528 [wR(F2) = 0.1562] using anisotropic temperature factors for all atoms other than those associated with water molecules. The structure is based on highly corrugated (Si2O52-)∞ layers which can be generated by the condensation of xonotlite-like ribbons, which can, in turn, be generated by the condensation of wollastonite-like chains. The silicate layers are connected by Nd octahedra to form a three-dimensional framework. Potassium ions and water molecules are located in interstitial sites within this framework, in particular, within channels that extend along [001]. Aging of as-grown crystals at room temperature for periods of six months or more results in an ordering phenomenon that causes the length of the c axis to double. In addition, two phase transitions were found to occur upon heating. The high-temperature transformations, investigated by differential scanning calorimetry, thermal gravimetric analysis and high-temperature X-ray diffraction, are reversible, suggesting displacive transformations in which the layers remain intact. Conductivity measurements along all three crystallographic axes showed the conductivity to be greatest along [001] and further suggest that the channels present in the room-temperature structure are preserved at high temperatures so as to serve as pathways for easy ion transport. Ion-exchange experiments revealed that silver can readily be incorporated into the structure. (orig.)

  3. Synthesis and Crystal Structure of a Two-dimensional Silver(I)-Iron(III) Heteronuclear Coordination Polymer:{[Ag4Fe2(SCN)12(H2O)2] [(inaH)2(H2O)2]}n

    Institute of Scientific and Technical Information of China (English)

    LI,Xiu-Ling(李秀玲); TONG,Ming-Liang(童明良); NIU,De-Zhong(牛德仲); CHEN,Jiu-Tong(陈久桐)

    2004-01-01

    The 2-D heteronuclear coordination polymer {[Ag4Fe2(SCN)12(H2O)2] [(inaH)2(H2O)2]}n (1) (inaH is the abbreviation of protonated isonicotinic acid) with chemical formula C24H20Ag4Fe2N14O8S12 has been synthesized and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. The Ag2S2 rings connect two kinds of octahedral geometries of Fe(III) ions, [Fe(NCS)6]3- and [Fe(H2O)2(NCS)4]- units with bridging thiocyanate ions leading to 2-D [Ag4Fe2(SCN)12(H2O)2]2- anion framework. Four kinds of rings including the unprecedented thirty-two membered Ag4Fe4(SCN)8 rings share corners or edges in the 2-D anion layer structure. All thiocyanates coordinate to the metal ions according to the HSAB principle with N atoms binding to the Fe(III) ions and with S atoms binding to Ag(I) ions. Pronoated ina cations stabilize the layer structure as counter ions and hydrogen bonds were formed within the pronoated ina cations dimer and between the dimers and the lattice waters. Crystal data: Mr=1560.44, triclinic, P(1-) a=0.76082(1) nm, b=0.9234 nm, c=1.85611(4) nm, α=103.0170(10)°, β=93.7780(10)°, γ=97.4080(10), V=1.25385(3) nm3, Z=1, μ(Mo Kα)=2.650 mm-1, Dc=2.067 g·cm-3, F(000)=758, R1=0.0412, wR2=0.1003.

  4. Heat capacities and entropies from 8 to 1000 K of langbeinite (K2Mg2(SO4)3), anhydrite (CaSO4) and of gypsum (CaSO4·2H2O)

    Science.gov (United States)

    Robie, Richard A.; Russell-Robinson, Susan; Hemingway, Bruce S.

    1989-01-01

    Heat capacities of K2Mg2(SO4)3 (langbeinite) and CaSO4 (anhydrite) were measured from approximately 8 to 1000 K by combined adiabatic shield calorimetry (8-365 K) and differential scanning calorimetry (350-1000 K). Heat capacities were also measured on natural crystals of gypsum (CaSO4 · 2H2O) between 8.1 and 323.5 K. The molar entropies at 298.15 K, Smo(298.15 K), are 378.8 ± 0.6, 107.4 ± 0.2 and 193.8 ± 0.3 J K−1 mol−1 for langbeinite, anhydrite and gypsum, respectively. The heat capacity in J K−1 mol−1 of langbeinite can be represented by the equation Cp,mo(K2Mg2(SO4)3T) = 535.9 + 0.11011T-1.0200 × 106/T2-4.909 × 10−5T2 -4040.2/T0.5 between 300 and 1000 K with an average deviation of ± 0.4%. For anhydrite the heat capacity between 300 and 1000 K is given by Cp,mo(CaSO4,T) = 372.8 - 0.1574 T +1.695 × 106/T2 + 7.993 × 10−5T2 - 4330.8/T0.5 with an average deviation of ±0.4%.

  5. Synthesis and Crystal Structure of Copper (Ⅱ) Compound with 3,3'-Azobispyridine Ligand[Cu(NO3)2(H2O)2(3,3'-azpy)2

    Institute of Scientific and Technical Information of China (English)

    李宝龙; 郎建平; 王寿武; 徐正; 陈久桐

    2003-01-01

    The title complex [Cu(NO3)2(H2O)2(3,3'-azpy)2] (3,3'-azpy = 3,3'-azobispyridine) has been synthesized and characterized, and its crystal belongs to the triclinic system, space group P ī with the following crystallographic parameters: a = 7.4161(2), b = 8.1754(3), c = 10.7545(4) A。,α= 92.958(2),β= 109.978(1),γ = 93.369(2)°, V = 609.96(4) A。3, C20H20N10CuO8, Mr = 592.00, Dc = 1.612 g/cm3, μ(MoKα)= 0.964 mm-1, F(000) = 303, Z = 1, the final R = 0.0494 and wR = 0.1269 for 1945 observed reflections (I > 2((I)). X-ray analysis reveals that the Cu atom adopts a distorted octahedral (4 + 2) coordination. The four closer donor atoms include two N atoms of 3,3'-azpy and two Oatoms of the coordination aqua with the Cu-N and Cu-O distances of 2.014(3) and 1.974(3)A。, respectively. Two longer out-of-plane Cu-O bonds (2.450(3) A。) from nitrate complete the strongly distorted octahedral coordination of the Cu atom. Hydrogen bonds are formed through H atoms of each coordination aqua with the remaining N atoms of 3,3'-azpy and O atoms of nitrate. A two-dimensional network is constructed by hydrogen bonds and π-π interactions.

  6. Electronic structure of the water oxidation catalyst cis,cis-[(bpy)2(H2O)Ru(III)ORu(III)(OH2)(bpy)2]4+, the blue dimer.

    Science.gov (United States)

    Jurss, Jonah W; Concepcion, Javier J; Butler, Jennifer M; Omberg, Kristin M; Baraldo, Luis M; Thompson, Darla Graff; Lebeau, Estelle L; Hornstein, Brooks; Schoonover, Jon R; Jude, Hershel; Thompson, Joe D; Dattelbaum, Dana M; Rocha, Reginaldo C; Templeton, Joseph L; Meyer, Thomas J

    2012-02-01

    The first designed molecular catalyst for water oxidation is the "blue dimer", cis,cis-[(bpy)(2)(H(2)O)Ru(III)ORu(III)(OH(2))(bpy)(2)](4+). Although there is experimental evidence for extensive electronic coupling across the μ-oxo bridge, results of earlier DFT and CASSCF calculations provide a model with magnetic interactions of weak to moderately coupled Ru(III) ions across the μ-oxo bridge. We present the results of a comprehensive experimental investigation, combined with DFT calculations. The experiments demonstrate both that there is strong electronic coupling in the blue dimer and that its effects are profound. Experimental evidence has been obtained from molecular structures and key bond distances by XRD, electrochemically measured comproportionation constants for mixed-valence equilibria, temperature-dependent magnetism, chemical properties (solvent exchange, redox potentials, and pK(a) values), XPS binding energies, analysis of excitation-dependent resonance Raman profiles, and DFT analysis of electronic absorption spectra. The spectrum can be assigned based on a singlet ground state with specific hydrogen-bonding interactions with solvent molecules included. The results are in good agreement with available experimental data. The DFT analysis provides assignments for characteristic absorption bands in the near-IR and visible regions. Bridge-based dπ → dπ* and interconfiguration transitions at Ru(III) appear in the near-IR and MLCT and LMCT transitions in the visible. Reasonable values are also provided by DFT analysis for experimentally observed bond distances and redox potentials. The observed temperature-dependent magnetism of the blue dimer is consistent with a delocalized, diamagnetic singlet state (dπ(1)*)(2) with a low-lying, paramagnetic triplet state (dπ(1)*)(1)(dπ(2)*)(1). Systematic structural-magnetic-IR correlations are observed between ν(sym)(RuORu) and ν(asym)(RuORu) vibrational energies and magnetic properties in a series of

  7. Self-encapsulation of [MII(phen)2(H2O)2]2+ (M=Co, Zn) in one-dimensional nanochannels of [MII(H2O)6(BTC)2]4- (M=Co, Cu, Mn): a high HQ/CAT ratio catalyst for hydroxylation of phenols.

    Science.gov (United States)

    Bi, Jianhong; Kong, Lingtao; Huang, Zixiang; Liu, Jinhuai

    2008-06-01

    Four novel three-dimensional (3D) microporous supramolecular compounds containing nanosized channels, namely, [Co(phen)2(H2O)2]2[Co(H2O)6].2BTC.21.5H2O (1), [Co(phen)2(H2O)2]2[Cu(H2O)6].2BTC.21.5H2O (2), [Co(phen)2(H2O)2]2[Mn(H2O)6].2BTC.18H2O (3), and [Zn(phen)2(H2O)2]2[Mn(H2O)6].2BTC.22.5H2O (4), were synthesized from 1,3,5-benzenetricarboxylate (BTC), 1,10-phenanthroline (phen), and the transition-metal salt(s) by self-assembly. Single-crystal X-ray structural analysis showed that the resulting 3D microporous supramolecular frameworks consist of a two-dimensional (2D) hydrogen-bonded host framework of [MII(H2O)6(BTC)2]4- (M=Co for 1, Cu for 2, Mn for 3, 4) with rectangular-shaped cavities containing [MII(phen)2(H2O)2]2+ (M=Co for 1-3, Zn for 4) guests. The guest complex is encapsulated in the 2D hydrogen-bonded host framework by hydrogen bonding and aromatic pi-pi stacking interactions, forming the 3D hydrogen-bonded framework. The catalytic activities of 1, 2, 3, and 4 were studied using hydroxylation of phenols with 30% aqueous H2O2 as a test reaction. The compounds displayed a good phenol conversion ratio and excellent channel selectivity in the hydroxylation reaction, with a maximum hydroquinone (HQ)/catechol (CAT) ratio of 3.9. PMID:18439004

  8. Nevadaite, (Cu2+, Al, V3+)6 [Al8 (PO4)8 F8] (OH 2 (H2O)22, a new phosphate mineral species from the Gold Quarry mine, Carlin, Eureka County, Nevada: description and crystal structure

    Science.gov (United States)

    Cooper, M.A.; Hawthorne, F.C.; Roberts, Andrew C.; Foord, E.E.; Erd, Richard C.; Evans, H.T., Jr.; Jensen, M.C.

    2004-01-01

    Nevadaite, (Cu2+, ???, Al, V3+)6 (PO4)8 F8 (OH)2 (H2O)22, is a new supergene mineral species from the Gold Quarry mine, near Carlin, Eureka County, Nevada, U.S.A. Nevadaite forms radiating clusters to 1 mm of prismatic crystals, locally covering surfaces more that 2 cm across; individual crystals are elongate on [001] with a length:width ratio of > 10:1 and a maximum diameter of ???30 ??m. It also occurs as spherules and druses associated with colorless to purple-black fluellite, colorless wavellite, strengitevariscite, acicular maroon-to-red hewettite, and rare anatase, kazakhstanite, tinticite, leucophosphite, torbernite and tyuyamunite. Nevadaite is pale green to turquoise blue with a pale powder-blue streak and a vitreous luster; it does not fluoresce under ultra-violet light. It has no cleavage, a Mohs hardness of ???3, is brittle with a conchoidal fracture, and has measured and calculated densities of 2.54 and 2.55 g/cm3, respectively. Nevadaite is biaxial negative, with ?? 1.540, ?? 1.548, ?? 1.553, 2V(obs.) = 76??, 2V(calc.) = 76??, pleochroic with X pale greenish blue, Y very pale greenish blue, Z blue, and with absorption Z ??? X > Y and orientation X = c, Y = a, Z = b. Nevadaite is orthorhombic, space group P21mn, a 12.123(2), b 18.999(2), c 4.961(1) A?? , V 1142.8(2) A??3, Z = 1, a:b:c = 0.6391:1:0.2611. The strongest seven lines in the X-ray powder-diffraction pattern [d in A??(I)(hkl)] are: 6.077(10)(200), 5.618(9)(130), 9.535(8)(020), 2.983(6)(241), 3.430(4)(041), 2.661(4)(061 , and 1.844(4)(352). A chemical analysis with an electron microprobe gave P2O5 32.54, Al2O3 27.07, V2O3 4.24, Fe2O3 0.07, CuO 9.24, ZnO 0.11, F 9.22, H2O (calc.) 23.48, OH ??? F -3.88, sum 102.09 wt.%; the valence states of V and Fe, and the amount of H2O, were determined by crystal-structure analysis. The resulting empirical formula on the basis of 63.65 anions (including 21.65 H2O pfu) is (CU2+2.00 Zn0.02 V3+0.98 Fe3+0.01 Al1.15)??4.16 Al8 P7.90 O32 [F8.37 (OH 1.63]??10 (H2O

  9. Targeting the environmental assessment of veterinary drugs with the multi-species-soil system (MS centred dot 3) agricultural soil microcosms: the ivermectin case study

    International Nuclear Information System (INIS)

    The environmental risk assessment of the veterinary pharmaceutical ivermectin is receiving significant attention. This paper assesses the capacity of the MS centred dot 3 soil microcosm as a tool for targeting the environmental impact assessment of veterinary drugs, using ivermectin as model. Two screening MS centred dot 3 were performed using different European soils; one with a soil collected in an agricultural station near to Madrid, Spain and a second with a soil collected in a farm area close to York, UK. Soils were fortified with ivermectin at the following ranges: 0.01-10 mg kg-1 and 0.1-100 mg kg-1 in the Madrid and York studies, respectively. The effects on earthworms, plants and soil microorganisms were assessed in the Madrid soil. Toxicity tests on aquatic organisms (algae, cladocerans and in vitro fish cell line RTLW1) were also conducted with the leachates. No effects were observed in earthworms and plants at any tested concentration; reduction in the respiration rate (-1 can be estimated. Comparisons based on toxicity data and equilibrium partitioning confirmed that the main risk is expected to be related to the high sensitivity of cladocerans. The results confirm that MS centred dot 3 systems are cost-effective tools for assessing the impact of veterinary pharmaceuticals when applied to agricultural land, as previously demonstrated for antimicrobials. (Author) 39 refs.

  10. Interaction of [Rh2(O2CCH3)4(H2O)2] and [Rh2(O2CCH(OH)Ph)2(phen)2(H2O)2](O2C-CH(OH)Ph)2 With Sulfhydryl Compounds and Ceruloplasmin

    OpenAIRE

    Jakimowicz, Piotr; Ostropolska, Lucja; Pruchnik, Florian P.

    2000-01-01

    The interaction of binuclear rhodium(II) complexes [Rh2(OOCCH3)4(H2O)2], [Rh2{OOCCH(OH)Ph}2(phen)2(H2O)2] {OOCCH(OH)Ph}2, [Rh2(OOCCH3)2(bpy)2(H2O)2](OOCCH3)2 and [Rh2Cl2(OOCMe)2(bpy)2](3H2O) with ceruloplasmin, cysteine, glutathione and coenzyme A have been investigated using. UV-Vis and CD spectroscopies. The complexes containing phen or bpy at pH = 7.4 and 4.0 are readily reduced with sulfhydryl compounds, while rhodium(II) acetate is relatively stable in these conditions. Complex [Rh2{OOCC...

  11. Batievaite-(Y), Y2Ca2Ti[Si2O7]2(OH)2(H2O)4, a new mineral from nepheline syenite pegmatite in the Sakharjok massif, Kola Peninsula, Russia

    Science.gov (United States)

    Lyalina, L. M.; Zolotarev, A. A.; Selivanova, E. A.; Savchenko, Ye. E.; Krivovichev, S. V.; Mikhailova, Yu. A.; Kadyrova, G. I.; Zozulya, D. R.

    2016-05-01

    Batievaite-(Y), Y2Ca2Ti[Si2O7]2(OH)2(H2O)4, is a new mineral found in nepheline syenite pegmatite in the Sakharjok alkaline massif, Western Keivy, Kola Peninsula, Russia. The pegmatite mainly consists of nepheline, albite, alkali pyroxenes, amphiboles, biotite and zeolites. Batievaite-(Y) is a late-pegmatitic or hydrothermal mineral associated with meliphanite, fluorite, calcite, zircon, britholite-group minerals, leucophanite, gadolinite-subgroup minerals, titanite, smectites, pyrochlore-group minerals, zirkelite, cerianite-(Ce), rutile, behoite, ilmenite, apatite-group minerals, mimetite, molybdenite, and nickeline. Batievaite-(Y) is pale-cream coloured with white streak and dull, greasy or pearly luster. Its Mohs hardness is 5-5.5. No cleavage or parting was observed. The measured density is 3.45(5) g/cm3. Batievaite-(Y) is optically biaxial positive, α 1.745(5), β 1.747(5), γ 1.752(5) (λ 589 nm), 2V meas. = 60(5)°, 2V calc. = 65°. Batievaite-(Y) is triclinic, space group P-1, a 9.4024(8), b 5.5623(5), c 7.3784(6) Å, α 89.919(2), β 101.408(2), γ 96.621(2)°, V 375.65(6) Å3 and Z = 1. The eight strongest lines of the X-ray powder diffraction pattern [d(Å)(I)(hkl)] are: 2.991(100)(11-2), 7.238(36)(00-1), 3.061(30)(300), 4.350(23)(0-1-1), 9.145(17)(100), 4.042(16)(11-1), 2.819(16)(3-10), 3.745(13)(2-10). The chemical composition determined by electron probe microanalysis (EPMA) is (wt.%): Nb2O5 2.25, TiO2 8.01, ZrO2 2.72, SiO2 29.96, Al2O3 0.56, Fe2O3 0.43, Y2O3 11.45, La2O3 0.22, Ce2O3 0.33, Nd2O3 0.02, Gd2O3 0.07, Dy2O3 0.47, Er2O3 1.07, Tm2O3 0.25, Yb2O3 2.81, Lu2O3 0.45, CaO 24.98, MnO 1.31, MgO 0.01, Na2O 1.13, K2O 0.02, F 2.88, Cl 0.19, H2O 6.75 (determined on the basis of crystal structure data), O = (F,Cl) -1.25, total 97.09 wt.%. The empirical formula based on the EPMA and single-crystal structure analyses is (Y0.81Ca0.65Mn0.15Zr0.12Yb0.11Er0.04Fe3+ 0.04Ce0.02Dy0.02Lu0.02La0.01Tm0.01)Σ2.00((H2O)0.75Ca0.70□0.55)Σ2.00Ca2.00(□0.61Na0.25( H2O

  12. 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.

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

    International Nuclear Information System (INIS)

    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. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  14. Novel example of stabilization of the BF3·H2O aquo complex in the [(BF3·H2O)2·18-crown-6·2H2O] compound of the 'guest-host' type

    International Nuclear Information System (INIS)

    [(BF3·H2O)2·18-crown-6·2H2O] complex synthesized by interaction BF3·(C2H5)2O with 18-crown-6 in the presence of moisture. The complex was identified using methods of 1H NMR, vibrational spectroscopy, thermogravimetry, X-ray diffraction analysis. The complex is crystallized in triclinic syngony: a = 7.250(1), b = 8.256(2), c = 10.346(1) A, α = 93.88(1), β = 108.61(2), γ = 111.40(2) deg, Z = 1, sp. gr. P1.14 refs., 3 figs., 1 tab

  15. Competition of the Peierls relief and structural defects in damping the domain walls in [Mn left brace (R/S)-pn right brace]2[Mn left brace(R/S)-pn right brace2(H2O)][Cr(CN)6]2 ferrimagnet

    International Nuclear Information System (INIS)

    The [ [Mn left brace (R/S)-pn right brace]2[Mn left brace(R/S)-pn right brace2(H2O)][Cr(CN)6]2 molecular ferrimagnet exhibits an inverse sequence of changes in the domain wall motion regimes with increasing temperature in alternative magnetic field of 0.04-1400 Hz frequency. Initiation of the relaxation regime on the background of creep indicates that there are two different systems of the domain walls damping. The threshold amplitude of the alternative magnetic field corresponds to the Peierls relief contribution to the domain wall dynamics as well as the defect contribution usually considered.

  16. Structural polymorphism in new organic-inorganic hybrid: Pyrazolium bromoantimonates(III) [C 3N 2H 5] 6Sb 4Br 18·2H 2O (tetragonal and triclinic forms). Thermal, dielectric and proton magnetic resonance ( 1H NMR) studies on the tetragonal form

    Science.gov (United States)

    Piecha, A.; Białońska, A.; Jakubas, R.; Medycki, W.

    2008-11-01

    Two polymorphic forms of pyrazolium bromoantimonates(III) - [C 3N 2H 5] 6Sb 4Br 18·2H 2O: α modification - tetragonal form and β modification - triclinic form, have been synthesized and structurally characterized at 100 K. The α-polymorph consists of a unique three-dimensional (3D) anionic substructure built up of cyclic tetramers and discrete chains linked to each other, three nonequivalent pyrazolium cations and water molecules. The β-polymorph is characterized by discrete cyclic anionic tetramers [Sb 4Br 18] -6, three nonequivalent cations and water molecules. The physical properties have been studied for the [C 3N 2H 5] 6Sb 4Br 18·2H 2O (α form). The differential scanning calorimetry (DSC) revealed a complex sequence of phase transitions above room temperature. The low-frequency dielectric relaxation process was found to appear at low temperatures, which was assigned to the dynamics of dipolar pyrazolium cations. The molecular motions of the pyrazolium cations in the α-polymorph were studied in a wide temperature range by means of a proton magnetic resonance ( 1H NMR) technique. Two minima of the spin-lattice relaxation time ( T1) are disclosed: at low temperatures a wide one attributed to a small-angle-libration of cations and motion of water molecules, whereas the high temperature one assigned to the reorientation of cation about its pseudo-fivefold axis.

  17. Synthesis, Characterization and Crystal Structure of an Inorganic-organic Composite Metatungstate: [Co(4,4'-bipy)2(H2O)4](4,4'-H2bipy)2[H2W12O40]·5.5H2O

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel hybrid compound [Co(4,4'-bipy)2(H2O)4](4,4'- H2bipy)2[H2W12O40]·5.5H2Ohas been synthesized from an acidified aqueous solution and characterized by elemental and thermal analyses, IR and UV spectroscopy, and single-crystal X-ray structure determination. Structure analysis indicates that the title compound is of monoclinic, space group C2/c, with a = 21.315(9), b = 15.303 (7), c = 24.139(10) (A), β = 105.170(5)o, V = 7599(6) (A)3, Mr = 3706.99, Z = 4, F(000) = 6616, Dc = 3.231, μ = 18.395 mm-1, R = 0.0652 and wR = 0.1594. X-ray crystallographic study shows that the title compound consists of one [Co(4,4'-bipy)2(H2O)4]2+ cation, two diprotonated 4,4'-bipyridine molecules, 5.5 water molecules of crystallization, and one metatungstate polyoxoanion [H2W12O40]6-, which approaches an effective Td point symmetry. TG-DTA analysis indicates that the framework of the metatungstate polyoxoanion is collapsed at 587.0 ℃.

  18. Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2 — Comparison of transformation products, ready biodegradability and toxicity

    International Nuclear Information System (INIS)

    The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H2O2, UV/Fe2+/H2O2 and UV/TiO2. Prescreening experiments varying the H2O2 and TiO2 concentrations were performed in order to set the best catalyst concentrations in the UV/H2O2 and UV/TiO2 experiments, whereas the UV/Fe2+/H2O2 process was optimized varying the pH, Fe2+ and H2O2 concentrations by means of the Box–Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe2+/H2O2 and UV/TiO2 processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H2O2 treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H2O2 treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable. - Highlights: • Full primary elimination of 5-FU was achieved in all the treatments. • None of the processes were able to fully mineralize 5-FU. • Six transformation products (TPs) were identified during

  19. Syntheses and Structural Researches of Nine-coordinate K3[TbIII(nta)2(H2O)]·5.5H2O and Eight-coordinate K3[YbIII(nta)2]·5H2O

    Institute of Scientific and Technical Information of China (English)

    王君; 张向东; 王钰; 张扬; 张朝红; 佟健

    2004-01-01

    The crystal and molecular structures of K3[TbIII(nta)2(H2O)](5.5H2O (nta = nitrilotriacetic acid) and K3[YbIII(nta)2](5H2O complexes have been determined by single-crystal Xray structural analyses. Because TbIII and YbIII have different ionic radii and electronic configura- tions, they take nine- and eight-coordinate structures with two nta ligands, respectively. The crystal of K3[TbIII(nta)2(H2O)](5.5H2O belongs to orthorhombic, space group Pccn with a = 1.6374(7), b = 1.9913(8), c = 1.5068(6) nm, V = 4.913(3) nm3, Z = 8, Mr = 769.54, Dc = 2.081 g/cm3, μ= 3.476 mm-1 and F(000) = 3048. The final R and wR are 0.0432 and 0.0916 for 4961 observed reflections (I > 2.0(σI)), and 0.0814 and 0.1042 for all 21921 reflections, respectively. The [TbIII(nta)2(H2O)]3- complex anion has a nine-coordinate pseudo-monocapped square anti-prismatic structure, in which two N and six O coordinated atoms are from two nta ligands and the left ninth O atom from one water molecule. The crystal of K3[YbIII(nta)2]·5H2O is of monoclinic, space group P21/c with a = 1.5579(5), b = 0.9981(3), c = 1.5956(5) nm, β = 109.776(5), V = 2.3348(13) nm3, Z = 4, Mr = 756.62, Dc = 2.153 g/cm3, μ= 4.624 mm-1 and F(000) = 1484. The final R and wR are 0.0253 and 0.0657 for 4123 observed reflections (I > 2.0(σI)), and 0.0320 and 0.0731 for all 9414 reflections, respectively. The [YbIII(nta)2]3- complex anion has an eight-coordination structure with a distorted square antiprismatic prism, in which each nta acts as a tetradentate ligand with one N atom from the amino group and three O atoms from the carboxylic groups.

  20. 十四烷基二甲基苄基氯化铵的合成及晶体结构%Crystal Structure and Characterization of Tetradecyl Dimethyl Benzyl Ammonium Chloride C23H42ClN·2H2O

    Institute of Scientific and Technical Information of China (English)

    王瑛; 纪明中; 严莲荷

    2005-01-01

    合成了标题化合物C23H42ClN·2H2O (CCDC No: 227826),得到无色柱状晶体.晶体属正交晶系,空间群为P21/c, 晶胞参数a=2.0510(4)nm,b=1.1720(2) nm,c=1.0800(2) nm, V=2.5959(9) nm3,Mr=404.06,Z=4,Dc=1.034 g/cm3,F(000)=896,R=0.0590,wR=0.1789.4个C-N键的键长范围在0.1498(4)~0.1535(4) nm,热分析表明标题化合物在370.6 ℃完全分解.

  1. Synthesis and Structural Characterization of 2-Pyrazinecarboxylate Copper Compound {[Cu2 (Pyz) 2 (H2O) 4]·SO4}n (Pyz=2-pyrazinic acid)%2-吡嗪羧酸铜配合物的合成及其结构表征

    Institute of Scientific and Technical Information of China (English)

    禹良才; 赖兰

    2009-01-01

    Solvothermal reaction of 2-pyrazinic acid with Cu(SO4) 2·5H2O yields the title complex {[Cu2 (Pyz) 2 (H2O) 4]·SO4}n (1), which was characterized by elemental analysis, IR and single crystal X-ray diffraction structural analysis. The complex 1 crystallizes in Monoclinic system, space group P21/c, with lattice parameters a=1.126 87(6)nm, b=0.073 511 (4) nm,c=1.185 06(7) nm,β=95.070(2)°,and V=0.977 83(9) nm3,Z=4,Dc=2.172 Mg·m-3. CCDC:692347.

  2. Theoretical investigation of structure and stability of complexes with molecular hydrogen of Cu+·(H2)n (n=1-4) and L·Cu+·H2 (L=CO,N2,H2O,NH3,CN- and BH4-) type

    International Nuclear Information System (INIS)

    Nonempirical MO LCAO SCF method was used to calculate structures and stability of Cu+ ion complexes with molecular hydrogen of Cu+·(H2)n and L·Cu+·H2 (L+CO,N2,H2O,NH3,CN- and BH4-) type. It was found that energies of successive addition of H2 molecules decreased monotonously from ∼54 to ∼13 kJ with n growth from 1 to 4. Energy of Cu+-H2 bond decreases if additional ligands L enter the coordination sphere of Cu+. This weakening is more pronounced for L=CO,N2 and BH4- (by ∼6-8 kJ), as compared with H2O,NH3 and CN-. Qualitative model for explaining slight effects of mutual effect of L and H2 is suggested. It is shown that π-acceptor properties of L ligands are the most important ones

  3. Cycloaddition of thiocyanate ion to cyanoguanidine in the presence of uranyl ion: synthesis and crystal structure of (C3N5H6S)2[(UO2)(C2O4)2(H2O)] · C2N4H4

    International Nuclear Information System (INIS)

    Uranyl complex (C3N5H6S)2[(UO2)(C2O4)2(H2O)] ·C2N4H4 has been synthesized, its X-ray diffraction study being conducted. It has been ascertained that the complex is crystallized in triclinic crystal system, space group P1-bar, a=8.5201(11), b=11.4027(14), c=14.329(2)A, α=103.182(5), β=99.607(6), γ=109.698(4)deg, Z=2, ρcalcd=2.258 g/cm3. The structure integrates a complex aquadioxalatouranylate-anion, two crystallographically nonequivalent cations of thioammelinium and a neutral molecule of cyanoguanidine. It is pointed out that uranyl ion serves as a catalyst of thioammelinium formation during synthesis of the complex mentioned

  4. Polynuclear complexes with bridging pyrophosphate ligands: synthesis and characterisation of {[(bipy)Cu(H2O)(mu-P2O7)Na2(H2O)6] x 4H2O}, {[(bipy)Zn-(H2O)(mu-P2O7)Zn(bipy)]2 x 14H2O} and {[(bipy)(VO)2]2(mu-P2O7)] x 5H2O}.

    Science.gov (United States)

    Doyle, Robert P; Nieuwenhuyzen, Mark; Kruger, Paul E

    2005-12-01

    The reaction in water of M(II) ions (M = Cu, 1; Zn, 2; VO, 3) with 2,2'-bipyridine (bipy) followed by Na4P2O7 leads to the formation of three new complexes which feature the pyrophosphate anion, P2O7(4-), as a bridging ligand. Single crystal X-ray diffraction revealed 1 to be {[(bipy)Cu(H2O)(micro-P2O7)Na2(H2O)6] x 4H2O}, and 2 as a tetranuclear Zn(II) complex, {[(bipy)Zn(H2O)(micro-P2O7)Zn(bipy)]2 x 14H2O}. The structure of 1 consists of a mononuclear [(bipy)Cu(H2O)(P2O7)]2- unit that links via a pyrophosphate bridge to two Na atoms. The hydrated six-coordinate Na atoms themselves join together through bridging water molecules to generate a 2D Na-water sheet. The structure of 2 consists of a tetranuclear Zn(II) cluster (dimer-of-dimers) with two pyrophosphate ligands bridging between four metal centres. Adjacent clusters interact through face-to-face pi-pi interactions via the bipy ligands to yield a 2D sheet. Adjacent sheets pack in register to create channels, which are filled by the water molecules of crystallisation. An intricate 2D H-bonded water network separates adjacent sheets and encapsulates the tetranuclear clusters. Aspects of the pyrophosphate coordination modes in 1 and 2 are of structural relevance to those found within the inorganic pyrophosphatases. Compound 3, {[(bipy)(VO)2]2(micro-P2O7)] x 5H2O}, was isolated as an insoluble lime-green powder. Its dinuclear structure was elucidated from elemental and thermal analysis, magnetic susceptibility measurement and IR spectroscopy. The latter displayed characteristic bridging pyrophosphate and signature V=O stretches, which were corroborated by contrast to the IR spectra of 1 and 2 and through comparison with those found in the structurally characterised dinuclear complex, {[(bipy)Cu(H2O)]2(micro-P2O7) x 7H2O}, 4. PMID:16471055

  5. Synthesis of high quality CdSe quantum dots through a mild solution-phase synthetic route

    International Nuclear Information System (INIS)

    High quality CdSe quantum dots are synthesized through a solution-phase synthesis technique with Cd(CH3COO)2.2H2O and Na2SeSO3 as precursors. In this synthesis approach, the participation of a novel terpyridine derivative provides much better control over growth dynamics of CdSe quantum dots, resulting in the suppression of the Ostwald ripening process of the particle size distribution during growth. The CdSe quantum dots meet the all requirements of high quality quantum dots.

  6. 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)

  7. A study of the x-irradiated Cs sub 5 H sub 3 (SO sub 4) sub 4 centre dot H sub 2 O crystal by EPR in the 80-415 K temperature range

    CERN Document Server

    Waplak, S; Baranov, A I; Shuvalov, L A

    1997-01-01

    The EPR spectra of the x-irradiated fast proton conductor Cs sub 5 H sub 3 (SO sub 4) sub 4 centre dot H sub 2 O were investigated in the temperature range of 80-415 K. Two kinds of paramagnetic SO sub 4 sup - centres with different proton configurations below about 370 K and freeze-out behaviour of one of them below about 200 K were observed. The role of acid proton dynamics with respect to the glassy-like transition is discussed. (author)

  8. Experimental determination of quartz solubility and melting in the system SiO2-H2O-NaCl at 15-20 kbar and 900-1100 °C: implications for silica polymerization and the formation of supercritical fluids

    Science.gov (United States)

    Cruz, Miguel F.; Manning, Craig E.

    2015-10-01

    We investigated quartz solubility and melting in the system SiO2-NaCl-H2O at 15-20 kbar and 900-1100 °C using hydrothermal piston-cylinder methods. The solubility of natural, high-purity quartz was determined by weight loss. Quartz solubility decreases with increasing NaCl mole fraction ( X NaCl) at fixed pressure and temperature. The decline is greatest at low X NaCl. The solubility patterns can be explained by changes in the concentration and identity of silica oligomers. Modeling of results at 1000 °C, 15 kbar, reveals that silica monomers and dimers predominate at low Si concentration (high X NaCl), that higher oligomers assumed to be trimers become detectable at X NaCl = 0.23, and that the trimers contain >50 % of dissolved Si at X NaCl = 0. The modeling further implies a hydration number for the silica monomer of 1.6, significantly lower than is observed in previous studies. Results at 15 kbar and 1100 °C provide evidence of two coexisting fluid phases. Although solubility could not be determined directly in these cases, the presence or absence of phases over a range of bulk compositions permitted mapping of the topology of the phase diagram. At 1100 °C, 15 kbar, addition of only a small amount of NaCl ( X NaCl = 0.05) leads to separation of two fluid phases, one rich in H2O and SiO2, the other rich in NaCl with lower SiO2. Textural identification of two fluids is supported by very low quench pH due to preferential partitioning of Na into the fluid that is rich in SiO2 and H2O, confirmed by electron microprobe analyses. The addition of NaCl causes the upper critical end point on the SiO2-H2O melting curve to migrate to significantly higher pressure. Correspondence between depolymerization and phase separation of SiO2-H2O-NaCl fluids indicates that polymerization plays a fundamental role in producing critical mixing behavior in silicate-fluid systems.

  9. Diffuse reflection infrared Fourier transform (DRIFT) spectra and high-temperature DRIFT spectra of beta-Ni(IO3)2.4H2O, Ni(IO3)2.2H2O, Mg(OH)2, and Zn(OH)F: novel embedding materials.

    Science.gov (United States)

    Pracht, G; Weckler, B; Lutz, H D

    2003-10-01

    Diffuse reflection infrared Fourier transform (DRIFT) spectra of the hydroxides Mg(OH)2 and Zn(OH)F and the iodate hydrates beta-Ni(IO3)2.4H2O and Ni(IO3)2.2H2O have been recorded at ambient and high temperature. Spectra without shifts of the band maxima compared to those of conventional infrared transmission spectra and without inversion of the bands were obtained by dilution of the compounds to about 2-10% with an appropriate embedding material. alpha-Al2O3, TiO2, ZrO2, PbF2, MgO, BaO, ZnO, Na2SiO3, SiO2 (aerosil), and powdered copper, aluminum, and magnesium were tested as diluents for hydrates and hydroxides, especially at elevated temperatures, as alternatives for the commonly used KBr. Thus, alpha-Al2O3, PbF2, and powdered copper were established as the most favorable diluents. Using these novel embedding materials, high-temperature DRIFT spectra are obtainable at temperatures not accessible with KBr discs. Dehydration and decomposition of the iodate hydrates under study were shown by change or disappearance of the respective water bands. PMID:14639754

  10. Synthesis and structural characterisation of new ettringite and thaumasite type phases: Ca6[Ga(OH)6·12H2O]2(SO4)3·2H2O and Ca6[M(OH)6·12H2O]2(SO4)2(CO3)2, M = Mn, Sn

    Science.gov (United States)

    Norman, Rachel L.; Dann, Sandra E.; Hogg, Simon C.; Kirk, Caroline A.

    2013-11-01

    Investigations into the formation of new ettringite-type phases with a range of trivalent and tetravalent cations were carried out to further study the potential this structure type has to incorporate cations covering a range of ionic radii (0.53-0.69 Å). We report the synthesis and structural characterisation of a new ettringite-type phase, Ca6[Ga(OH)6·12H2O]2(SO4)3·2H2O, which was indexed in space group P31c with the unit cell parameters a = 11.202(2) Å, c = 21.797(3) Å and two new thaumasite-type phases Ca6[M(OH)6·12H2O]2(SO4)2(CO3)2, M = Mn, Sn which were indexed in space group P63 with the unit cell parameters a = 11.071(5) Å, c = 21.156(8) Å and a = 11.066(1) Å, c = 22.420(1) Å respectively. These new phases show the versatility of the ettringite family of structures to tolerate a large range of cation sizes on the octahedral M site and highlights the preference of tetravalent cations to crystallise with the thaumasite structure over the ettringite structure.

  11. Synthesis and Physico-chemical studies of a new non-centrosymmetric organic-inorganic hybrid material: [2,3-(CH3)2C6H3NH3]4 BiBr6NO3.2H2O

    Indian Academy of Sciences (India)

    Z Aloui; V Ferretti; S Abid; M Rzaigui; C Ben Nasr

    2015-03-01

    Organic-inorganic hybrid single crystals of [2,3-(CH3)2C6H3NH3]4BiBr6NO3.2H2O were obtained by slow evaporation at room temperature and characterized by X-ray diffraction, IR and solid state NMR. This compound crystallizes in orthorhombic non-centrosymmetric space group Pca21 with the following lattice parameters: a=25.8217(1), b=7.8909(2), c=21.4328(3) Å, V=4367.07(13) Å3 and Z=4. The structure was refined to R = 0.057 for 7069 independent reflections. The crystal is built up of 2,3-dimethylanilinium cations, [BiBr66]3−, disordered [NO3] anions and water molecules. The crystal packing is governed by a threedimensional network of O-H... O, N-H... O and N-H... Br hydrogen bonds and van derWaals interaction. The infrared spectrum has been interpreted on the basis of literature data. Solid state 13C CP-MAS-NMR spectrum is in agreement with the X-ray structure.

  12. Two different zinc(II)-aqua complexes held up by a metal-oxide based support: Synthesis, crystal structure and catalytic activity of [HMTAH]2[{Zn(H2O)5}{Zn(H2O)4}{Mo7O24}].2H2O (HMTAH = protonated hexamethylenetetramine)

    Indian Academy of Sciences (India)

    T Arumuganathan; A Srinivasarao; T Vijay Kumar; Samar K Das

    2008-01-01

    An inorganic−organic hybrid material, [HMTAH]2[{Zn(H2O)5}{Zn(H2O)4}{Mo7O24}].2H2O (1) (where HMTAH = protonated hxamethylenetetramine) has been synthesized and structurally characterized. The compound 1 crystallizes in a monoclinic space group 2/. The crystal data of 1: = 43.12(3), = 12.399(10), = 16.285(13), = 111.131(11), = 8. Its crystal structure shows that two different Zn(II)-aqua complexes, [Zn(H2O)5]2+ and [Zn(H2O)4]2+ are covalently coordinated to a heptamolybdateanion [Mo7O24]6- resulting in an anionic species of polyoxometalate supported zinc-aqua complexes, [{Zn(H2O)}{Zn(H2O)4}{Mo7O24}]2-, that is stabilized with two protonated hexamethylenetetramine cations in the title compound 1. In the crystal structure, both lattice water molecules are found to interact with the heptamolybdate cluster anion and the protonated hexamethylenetetramine cation resulting in an intricate three-dimensional hydrogen bonding network. Interestingly, compound 1 exhibits catalytic activity towards oxidation of some primary alcohols.

  13. Two mixed-ligand lanthanide–hydrazone complexes: [Pr(NCS3(pbh2]·H2O and [Nd(NCS(NO3(pbh2(H2O]NO3·2.33H2O [pbh is N′-(pyridin-2-ylmethylidenebenzohydrazide, C13H11N3O

    Directory of Open Access Journals (Sweden)

    Damianos G. Paschalidis

    2016-02-01

    Full Text Available The gel-mediated syntheses and crystal structures of [N′-(pyridin-2-ylmethylidene-κNbenzohydrazide-κ2N′,O]tris(thiocyanato-κNpraseodymium(III monohydrate, [Pr(NCS3(C13H11N3O2]·H2O, (I, and aqua(nitrato-κ2O,O′[N′-(pyridin-2-ylmethylidene-κNbenzohydrazide-κ2N′,O](thiocyanato-κNneodymium(III nitrate 2.33-hydrate, [Nd(NCS(NO3(C13H11N3O2(H2O]NO3·2.33H2O, (II, are reported. The Pr3+ ion in (I is coordinated by two N,N,O-tridentate N′-(pyridin-2-ylmethylidenebenzohydrazide (pbh ligands and three N-bonded thiocyanate ions to generate an irregular PrN7O2 coordination polyhedron. The Nd3+ ion in (II is coordinated by two N,N,O-tridentate pbh ligands, an N-bonded thiocyanate ion, a bidentate nitrate ion and a water molecule to generate a distorted NdN5O5 bicapped square antiprism. The crystal structures of (I and (II feature numerous hydrogen bonds, which lead to the formation of three-dimensional networks in each case.

  14. Synthesis, structural characterization, and solid-state NMR spectroscopy of [Ga(phen)(H1.5PO4)2].H2O and [Ga(phen)(HPO4)(H2PO4)].1.5H2O (phen=1, 10-phenanthroline), two organic-inorganic hybrid compounds with 1-D chain structures

    International Nuclear Information System (INIS)

    Two new organic-inorganic hybrid compounds, [Ga(phen)(H1.5PO4)2].H2O (1) and [Ga(phen)(HPO4)(H2PO4)].1.5H2O (2) (phen=1,10-phenanthroline), have been synthesized by hydrothermal methods and structurally characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and solid-state NMR spectroscopy. Their structures consist of 1-D chains of strictly alternating GaO4N2 octahedra and phosphate tetrahedra. The phen ligands in both compounds bind in a bidentate fashion to the gallium atoms and the 1-D structures extend into 3-D supramolecular arrays via π-π stacking interactions of phen ligands and hydrogen bonds. 2H MAS NMR spectroscopy was applied to study the deuterated sample of 1 which contains very short hydrogen bonds with an O-O distance of 2.406(2) A. Crystal data for 1: monoclinic, space group C2/c (No. 15), a=11.077(1) A, b=21.496(2) A, c=7.9989(7) A, β=127.211(2)o, and Z=4. The crystal symmetry is the same for 2 as for 1 except a=27.555(2) A, b=6.3501(5) A, c=21.327(2) A, β=122.498(1)o, and Z=8

  15. Crystal structures of two decavanadates(V with pentaaquamanganese(II pendant groups: (NMe42[V10O28{Mn(H2O5}2]·5H2O and [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O

    Directory of Open Access Journals (Sweden)

    Maurício P. Franco

    2015-02-01

    Full Text Available Two heterometallic decavanadate(V compounds, bis(tetramethylammonium decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V pentahydrate, (Me4N2[V10O28{Mn(H2O5}2]·5H2O, A, and bis{[tris(hydroxymethylmethyl]ammonium} decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V dihydrate, [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O, B, have been synthesized under mild reaction conditions in an aqueous medium. Both polyanions present two [Mn(OH25]2+ complex units bound to the decavanadate cluster through oxide bridges. In A, the decavanadate unit has 2/m symmetry, whereas in B it has twofold symmetry. Apart from this, the main differences between A and B rest on the organic cations, tetramethylammonium and [tris(hydroxymethylmethyl]ammonium, respectively, and on the number and arrangement of the water molecules of crystallization. In both compounds, the H atoms from the coordinating water molecules participate in extensive three-dimensional hydrogen-bonding networks, which link the cluster units both directly and through solvent molecules and, in B, through the `tris' cation hydroxyl groups. The cation in B also participates in N—H...O hydrogen bonds. A number of C—H...O interactions are also observed in both structures.

  16. Holo- and hemidirected lead(II) in the polymeric [Pb(4)(mu-3,4-TDTA)2(H2O)2]*4H2O complex. N,N,N',N'-tetraacetate ligands derived from o-phenylenediamines as sequestering agents for lead(II).

    Science.gov (United States)

    Sanchiz, Joaquín; Esparza, Pedro; Villagra, Diego; Domínguez, Sixto; Mederos, Alfredo; Brito, Felipe; Araujo, Lorena; Sánchez, Agustin; Arrieta, Juan Manuel

    2002-11-18

    The coordinating ability of the ligands 3,4-toluenediamine-N,N,N',N'-tetraacetate (3,4-TDTA), o-phenylenediamine-N,N,N',N'-tetraacetate (o-PhDTA), and 4-chloro-1,2-phenylenediamine-N,N,N',N'-tetraacetate (4-Cl-o-PhDTA) (H4L acids) toward lead(II) is studied by potentiometry (25 degrees C, I = 0.5 mol x dm(-3) in NaClO4), UV-vis spectrophotometry, and 207Pb NMR spectrometry. The stability constants of the complex species formed were determined. X-ray diffraction structural analysis of the complex [Pb4(mu-3,4-TDTA)4(H2O)2]*4H2O (1) revealed that 1 has a 2-D structure. The layers are built up by the polymerization of centrosymmetric [Pb4L2(H2O)2] tetranuclear units. The neutral layers have the aromatic rings of the ligands pointing to the periphery, whereas the metallic ions are located in the central part of the layers. In compound 1, two types of six-coordinate lead(II) environments are produced. The Pb(1) is coordinated to two nitrogen atoms and four carboxylate oxygens from the ligand, whereas Pb(2) has an O6 trigonally distorted octahedral surrounding. The lead(II) ion is surrounded by five carboxylate oxygens and a water molecule. The carboxylate oxygens belong to four different ligands that are also joined to four other Pb(1) ions. The selective uptake of lead(II) was analyzed by means of chemical speciation diagrams as well as the so-called conditional or effective formation constants K(Pb)eff. The results indicate that, in competition with other ligands that are strong complexing agents for lead(II), our ligands are better sequestering agents in acidic media. PMID:12425632

  17. Two fumarato-bridged Co(II) coordination polymers: syntheses, crystal structures and properties of Co(H2O)4L and [Co3(H2O)4(OH)2L2]·2H2O with H2L-HOOCCH-CHCOOH

    International Nuclear Information System (INIS)

    Two fumarato-bridged Co(II) coordination polymers Co(H2O)4L 1 and [Co3(H2O)4(OH)2L2]·2H2O 2 with H2L-HOOCCH-CHCOOH were prepared. Complex 1 consists of polymeric chains ∞1[Co(H2O)4(C4H2O4)2/2], which result from octahedrally coordinated Co atoms bridged by bis-monodentate fumarate anions and are assembled by interchain hydrogen bonds. Within 2, the edge-shared Co2O10 bi-octahedra are connected to the CoO6 octahedra to form 1D cobalt oxide chains and 3D open framework generated from the chains inter-linked by bis-bidentate fumarate anions displays rhombic tunnels, which are filled with the lattice H2O molecules. Thermal and magnetic behaviors of both the title coordination polymers are discussed. Crystal data: (1) monoclinic, P21/c, Z=4, a=7.493(1) A, b=14.377(1) A, c=7.708(1) A, β=99.54(1) deg., V=818.9(2) A3, R1=0.0304, and wR2=0.0669 for 1487 observed reflections (I≥2σ(I)) out of 1877 unique reflections; (2) monoclinic, P21/c, Z=2, a=6.618(1) A, b=8.172(2) A, c=15.578(3) A, β=96.30(3) deg., V=837.4(3) A3, R1=0.0360 and wR2=0.0663 for 1442 observed reflections (I≥2σ(I)) out of 1927 unique reflections

  18. Common Building Motifs in Ba2Fe3(PO4)4·2H2O, BaFe3(PO4)3, and Na3Fe3(PO4)4: Labile Fe(2+)/Fe(3+) Ordering and Charge-Dependent Magnetism.

    Science.gov (United States)

    David, Rénald; Pautrat, Alain; Kabbour, Houria; Mentré, Olivier

    2016-05-01

    Two new mixed-valence Fe(2/3+) barium phosphates have been synthesized in hydrothermal conditions and characterized: Ba2Fe(2.66+)3(PO4)4·2H2O (compound 1, ratio Fe(3+)/Fe(2+) = 2:1, orthorhombic space group Pbca, a = 6.71240(10) Å, b = 10.6077(2) Å, c = 20.9975(5) Å, R1 = 3.39%) and BaFe(2.33+)3(PO4)3 (compound 2, ratio Fe(3+)/Fe(2+) = 1:2, orthorhombic, space group Imma with a = 10.5236(3) Å, b = 13.4454(4) Å, c = 6.6411(2) Å, R1 = 1.63%). 1 has a two-dimensional crystal structure built of [Fe(2.5+)2Fe(3+)1(PO4)4](4-) layers with charge segregation on two individual Fe crystal sites, in contrast to the single valence on these two sites found in similar layers of Na3Fe(3+)3(PO4)4. The crystal structure of 2 is formed of the same layers but condensed into a 3D [Fe(2+)2Fe(3+)1(PO4)3](2-) framework. The complete Fe(2+) vs Fe(3+) charge ordering on the two available sites differs from what was found in the two previous cases and denotes a remarkable charge adaptability of the common elementary units. Compared to the antiferromagnetic Na3Fe(3+)3(PO4)4 the partial iron reduction into Fe(2+) is responsible for strong ferromagnetic components along the c-easy axis for both 1 and 2. Additionally 1 shows multiple magnetization steps in the perpendicular direction, giving raise to atypical anisotropic magnetism into a complex magnetic phase diagram. PMID:27097360

  19. Hydrothermal syntheses, crystal structures and magnetic properties of two inorganic-organic hybrid materials: [{Cu(phen)}2(VVO2)2VIVO2(H2O)(PO4)2] and [V4O7(2,2'-bpy)2(HPO4)2] (phen=1,10-phenathroline, bpy=bipyridine)

    International Nuclear Information System (INIS)

    Two two-dimensional inorganic-organic hybrid materials formulated as [{Cu(phen)}2(VVO2)2VIVO2(H2O)(PO4)2] 1 and [V4O7(2,2'-bpy)2(HPO4)2] 2 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Both crystallize in the triclinic space group P1-bar (no. 2), with cell parameters a=8.118(3), b=9.272(3), c=10.348(5) A, α=96.71(1), β=100.97(1), γ=104.66(1) deg. , V=728.5(5) A3, Z=1 for 1 and a=8.402(4), b=9.270(5), c=9.676(7) A, α=97.10(1), β=110.29(1), γ=98.92(1) deg. , V=685.4(7) A3, Z=1 for 2. The structure of 1 is analogous to that of [{Cu(phen)}2(VVO2)3(OH)(PO4)2] (1') and consists of [{Cu(phen)}2VIVO6(H2O)]∞ chains that are bridged by {(VO2)(PO4)}2 4-membered rings via oxygen atoms into a two-dimensional network. Compounds 1 and 1' are isostructural but the oxidization states of vanadium atoms in them are not fully same. Thus, 1 and 1' are relatively rare examples of all V(V) and V(V)/V(IV) mixed valence analogues in the solid state. Compound 2 is also relatively uncommon and features 2,2'-bipy ligands directly coordinated to vanadium atoms. The structure of 2 is constructed by 4-, 6- and 8-membered rings and is topologically relevant to [V3O7(phen)]. The temperature-dependent magnetic susceptibility of 1 shows alternating ferro- and antiferromagnetic interactions

  20. 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.

  1. Crystal and molecular structure of the coordination compounds of Er3+ with 1-(methoxydiphenylphosphoryl)-2-diphenylphosphorylbenzene [ErL21(NO3)2]2[Er(NO3)2(H2O)5]0.333(NO3)2.333 · 2.833H2O and its ethyl substituted derivative [ErL22(NO3)2][Er(NO3)5]0.5 · 0.5H2O

    International Nuclear Information System (INIS)

    The coordination compounds of Er3+ with 1-(methoxydiphenylphosphoryl)-2-diphenylphosphorylbenzene [ErL21(NO3)2]2[Er(NO3)2(H2O)5]0.333(NO3)2.333 · 2.833H2O (I) and its ethyl substituted derivative [ErL22(NO3)2][Er(NO3)5]0.5 · 0.5H2O (II) are synthesized and their crystal structures are studied. I and II contain [ErL2(NO3)2]+ complex cations of identical composition and close structure. The eight-vertex polyhedron of the Er atom in the shape of a distorted octahedron with two split trans vertices is formed by the O atoms of the phosphoryl groups of L ligands and nitrate anions. L ligands close nine-membered metallocycles. The structures contain spacious channels which are populated differently, namely, by disordered [Er(NO3)2(H2O)5]+ complex cations, NO3− anions, and crystallization water molecules in I and disordered [Er(NO3)5]2− complex anions and crystallization water molecules in II. The IR spectra of I and II are studied

  2. Crystal and molecular structure of the coordination compounds of Er3+ with 1-(methoxydiphenylphosphoryl)-2-diphenylphosphorylbenzene [Er L {2/1}(NO3)2]2[Er(NO3)2(H2O)5]0.333(NO3)2.333 · 2.833H2O and its ethyl substituted derivative [Er L {2/2}(NO3)2][Er(NO3)5]0.5 · 0.5H2O

    Science.gov (United States)

    Polyakova, I. N.; Baulin, V. E.; Ivanova, I. S.; Pyatova, E. N.; Sergienko, V. S.; Tsivadze, A. Yu.

    2015-01-01

    The coordination compounds of Er3+ with 1-(methoxydiphenylphosphoryl)-2-diphenylphosphorylbenzene [Er L {2/1}(NO3)2]2[Er(NO3)2(H2O)5]0.333(NO3)2.333 · 2.833H2O ( I) and its ethyl substituted derivative [Er L {2/2}(NO3)2][Er(NO3)5]0.5 · 0.5H2O ( II) are synthesized and their crystal structures are studied. I and II contain [Er L 2(NO3)2]+ complex cations of identical composition and close structure. The eight-vertex polyhedron of the Er atom in the shape of a distorted octahedron with two split trans vertices is formed by the O atoms of the phosphoryl groups of L ligands and nitrate anions. L ligands close nine-membered metallocycles. The structures contain spacious channels which are populated differently, namely, by disordered [Er(NO3)2(H2O)5]+ complex cations, NO{3/-} anions, and crystallization water molecules in I and disordered [Er(NO3)5]2- complex anions and crystallization water molecules in II. The IR spectra of I and II are studied.

  3. Precipitation kinetics of calcite in the system CaCO 3H2OC02: The conversion to CO 2 by the slow process H ++HCO 3- → CO 2+H 2O as a rate limiting step

    Science.gov (United States)

    Dreybrodt, W.; Eisenlohr, L.; Madry, B.; Ringer, S.

    1997-09-01

    Precipitation rates of CaCO 3 from supersaturated solutions in the H 2OCO 2CaCO 3 system are controlled by three rate-determining processes: the kinetics of precipitation at the mineral surface, mass transport of the reaction species involved to and from the mineral surface, and the slow kinetics of the overall reaction HCO 3-+H + → CO 2+H 2O. A theoretical model by Buhmann and Dreybrodt (1985a,b) taking these processes into account predicts that, due to the slow kinetics of this reaction, precipitation rates to the surface of CaC0 3 minerals depend critically on the ratio V/A of the volume V of the solution to the surface area A of the mineral in contact with it, for both laminar and turbulent flow. We have performed measurements of precipitation rates in a porous medium of sized particles of marble, limestone, and synthetic calcite, with V/A ratios ranging from 3·10 -4 to 1.2·10 -2 cm at 10°C. Calcite was precipitated from supersaturated solutions with [Ca 2+] ≈ 4 mmol/L and an initial PCO2 of 5·10 -3 or 1·10 -3 atm, respectively, using experimental conditions which prevented exchange of CO 2 with the atmosphere, i.e., closed system. The results are in qualitative agreement with the theoretical predictions. Agreement with the observed data, however, is obtained by modifying the rate law of Plummer et al. (1978) to take into account surface-controlled inhibition effects. Experiments with supersaturated solutions containing carbonic anhydrase, an enzyme which enhances the conversion of HCO 3- into CO 2, yield rates increased by a factor of up to 15. This provides for the first time unambiguous experimental evidence that this reaction is rate limiting. We have also measured precipitation rates in batch experiments, stirring sized mineral particles in a solution with V/A ranging from 0.03 to 0.75 cm. These experiments also give clear evidence on the importance of the conversion of HCO 3- into CO 2 as rate limiting step. Taken together our experiments

  4. Ultra-large scale synthesis of high electrochemical performance SnO2 quantum dots within 5 min at room temperature following a growth self-termination mechanism

    International Nuclear Information System (INIS)

    Highlights: • SnO2 quantum dots were prepared at an ultra-large scale at room temperature within 5 min. • The grinding of SnCl2⋅2H2O and ammonium persulphate with morpholine produces quantum dots. • The reactions were self-terminated through the rapid consumption of water. • The obtained SnO2 quantum dots own high electrochemical performance. - Abstract: SnO2 quantum dots are prepared at an ultra-large scale by a productive synthetic procedure without using any organic ligand. The grinding of solid mixture of SnCl2⋅2H2O and ammonium persulphate with morpholine in a mortar at room temperature produces 1.2 nm SnO2 quantum dots within 5 min. The formation of SnO2 is initiated by the reaction between tin ions and hydroxyl groups generated from hydrolysis of morpholine in the released hydrate water from SnCl2⋅2H2O. It is considered that as water is rapidly consumed by the hydrolysis reaction of morpholine, the growth process of particles is self-terminated immediately after their transitory period of nucleation and growth. As a result of simple procedure and high toleration to scaling up of preparation, at least 50 g of SnO2 quantum dots can be produced in one batch in our laboratory. The as prepared quantum dots present high electrochemical performance due to the effective faradaic reaction and the alternative trapping of electrons and holes

  5. 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

  6. Infrared Spectra of the CO_2-H_2O, CO_2-(H_2O)2, and (CO_2)2-H_2O Complexes Isolated in Solid Neon Between 90 and 5300 wn

    Science.gov (United States)

    Tremblay, Benoît; Soulard, Pascale

    2015-06-01

    The van der Waals complex of H_2O with CO_2 has attracted considerable theoretical interest since it is a typical example of a weak binding complex (less than 3 kcal/mol), but a very few IR data are available in gas. For these reasons, we have studied in solid neon hydrogen bonded complexes involving carbon dioxide and water molecules. Evidence for the existence of at least three (CO_2)m(H_2O)n, or m:n, complexes has been obtained from the appearance of many new absorptions near the well-know monomers fundamental transitions. Concentration effects and detailed vibrational analysis allowed identification of fifteen, eleven and four transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra+intermolecular transitions. All of these results significantly increase the number of one and, especially, two quanta vibrational transitions observed for these complexes, and anharmonic coupling constants have been derived. This study shows the high sensibility of the solid neon isolation for the spectroscopy of the hydrogen-bonded complexes since two quanta transitions can't be easily observed in gas phase.

  7. ZnO-dotted porous ZnS cluster microspheres for high efficient, Pt-free photocatalytic hydrogen evolution

    OpenAIRE

    Aiping Wu; Liqiang Jing; Jianqiang Wang; Yang Qu; Ying Xie; Baojiang Jiang; Chungui Tian; Honggang Fu

    2015-01-01

    The Pt-free photocatalytic hydrogen evolution (PHE) has been the focus in the photocatalysis field. Here, the ZnO-dotted porous ZnS cluster microsphere (PCMS) is designed for high efficient, Pt-free PHE. The PCMS is designed through an easy “controlling competitive reaction” strategy by selecting the thiourea as S2− source and Zn(Ac)2 ·2H2O as Zn source in ethylene glycol medium. Under suitable conditions, one of the PCMS, named PCMS-1, with high SBET specific area of 194 m2g−1, microsphere s...

  8. Incommensurate phases in the improper ferroelastic MgGeF sub 6 centre dot 6H sub 2 O:Mn sup 2 sup + studied by means of EPR

    CERN Document Server

    Skrylnik, P G

    2002-01-01

    The results of an EPR study of the inhomogeneous phases existing in the temperature interval T sub C = 311.0 +- 0.3 K < T < T sub i sub 1 = 403 +- 0.3 K in improper ferroelastic crystals of MgGeF sub 6 centre dot 6H sub 2 O:Mn sup 2 sup + are presented. On the basis of the analysis of the temperature and angle dependences of the experimental parameters and numerical calculations, the conclusion has been drawn that at T sub i sub 1 the crystals considered undergo a transition to a structurally modulated phase and the order parameter of this transition may be the angle of the Mg[H sub 2 O] sub 6 sup 2 sup + octahedra rotation around the crystal C sub 3 -axis. From T sub i sub 1 to T sub C the modes of the modulated phase follow according to a completely classical scenario for incommensurate crystals: the origin of the incommensurate structure with plane-wave modulation at T sub i sub 1 , the appearance of structural phase solitons below T sub i sub 2 = 380 +- 0.3 K and decrease of the soliton density to v...

  9. Quantum dots

    CERN Document Server

    Borovitskaya, Elena

    2002-01-01

    In this book, leading experts on quantum dot theory and technology provide comprehensive reviews of all aspects of quantum dot systems. The following topics are covered: (1) energy states in quantum dots, including the effects of strain and many-body effects; (2) self-assembly and self-ordering of quantum dots in semiconductor systems; (3) growth, structures, and optical properties of III-nitride quantum dots; (4) quantum dot lasers. Contents: Low-Dimensional Systems (E Borovitskaya & M S Shur); Energy States in Quantum Dots (A J Williamson); Self-Organized Quantum Dots (A R Woll et al.); Grow

  10. Crystal and molecular structure of four copper(II) ethylenediaminedisuccinates, [Cu2(RR,SS-Edds)] . 6H2O, Ba2[Cu(RR,SS-Edds)](ClO4)2 . 8H2O, Ba[Cu(SS-HEdds)]ClO4 . 2H2O, and Ba3[Cu2(RR,SS-Edds)2](ClO4)2 . 6H2O

    International Nuclear Information System (INIS)

    Four Cu(II) complexes with the RR,SS-Edds4- and SS-HEdds3- anions are synthesized, and their crystal structures are studied. In the compounds [Cu2(RR,SS-Edds)] . 6H2O (I) and Ba2[Cu(RR,SS-Edds)](ClO4)2 . 8H2O (II), the ligand forms hexacoordinate chelate [Cu(Edds)]2- complexes with the N atoms and O atoms of the propionate groups in the equatorial positions and the O atoms of the acetate groups in the axial vertices. In the compounds Ba[Cu(SS-HEdds)]ClO4 . 2H2O (III) and Ba3[Cu2(RR,SS-Edds)2](ClO4)2 . 6H2O (IV), one of the propionate arms, the protonated arm in III and the deprotonated arm in IV, does not enter into the coordination sphere of the Cu atom. An acetate arm moves to its position in the equatorial plane, and the free axial vertex is occupied by an O atom of the perchlorate ion. In I-IV, the lengths of the equatorial Cu-N and Cu-O bonds fall in the ranges 1.970-2.014 and 1.921-1.970 A, respectively. The axial Cu-O bonds with the acetate groups and ClO4- anions are elongated to 2.293-2.500 and 2.727-2.992 A, respectively. In structure I, the second Cu atom acts as a counterion forming bonds with the O atoms of two water molecules and three O atoms of the Edds ligands. In II-IV, the Ba2+ cations are hydrated and bound to the O atoms of the anionic complexes and (except for one of the cations in IV) ClO4- anions. The coordination number of the Ba cations is nine. The structural units in I-IV are connected into layers. In I, an extended system of hydrogen bonds links the layers into a framework. In II and III, the layers are linked only by weak hydrogen bonds, one bond per structural unit. In IV, ClO4- anions are bound to the Ba and Cu atoms of neighboring layers, thus serving as bridges between the layers.

  11. 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.

  12. Effect of the greenhouse gases (CO2, H2O, SO2) on Martian paleoclimate

    Science.gov (United States)

    Postawko, S. E.; Kuhn, W. R.

    1986-01-01

    There is general agreement that certain surface features on Mars are indicative of the presence of liquid water at various times in the geologic past. In particular, the valley networks are difficult to explain by a mechanism other than the flow of liquid water. It has been suggested in several studies that a thick CO2 atmosphere on Mars early in its history could have provided a greenhouse warming that would have allowed the flow of water either on the surface or just below the surface. However, this effect was examined with a detailed radiation model, and it was found that if reduced solar luminosity early in the history of the solar system is taken into account, even three bars of CO2 will not provide sufficient greeenhouse warming. The addition of water vapor and sulflur dioxide (both plausible gases that may have been emitted by Martian volcanoes) to the atmosphere also fail to warm the surface above 273 K for reduced solar luminosity conditions. The increase in temperature may be large enough, however, for the formation of these features by brines.

  13. Dual passivation of GaAs (110) surfaces using O2/H2O and trimethylaluminum

    International Nuclear Information System (INIS)

    The nucleation and passivation of oxide deposition was studied on defect-free GaAs (110) surfaces to understand passivation of surfaces containing only III-V heterobonds. The passivation process on GaAs (110) was studied at the atomic level using scanning tunneling microscopy while the electronic structure was determined by scanning tunneling spectroscopy (STS). The bonding of the oxidant and reductant were modeled with density functional theory. To avoid Fermi level pinning during gate oxide atomic layer deposition, a dual passivation procedure was required using both a reductant, trimethylaluminum (TMA), and an oxidant, O2 or H2O. Dosing GaAs (110) with TMA resulted in the formation of an ordered complete monolayer of dimethylaluminum which passivates the group V dangling bonds but also forms metal-metal bonds with conduction band edge states. These edge states were suppressed by dosing the surface with oxidants O2 or H2O which selectively react with group III-aluminum bonds. The presence of an ordered Al monolayer with a high nucleation density was indirectly confirmed by XPS and STS

  14. The HO2 + (H2O)n + O3 reaction: an overview and recent developments*

    Science.gov (United States)

    Viegas, Luís P.; Varandas, António J. C.

    2016-03-01

    The present work is concerned with the reaction of the hydroperoxyl radical with ozone, which is key in the atmosphere. We first give a brief overview which emphasizes theoretical work developed at the authors' Group, considering not only the naked reaction (n = 0) but also the reaction with one water molecule added to the reactants (n = 1). Aiming at a broad and contextual understanding of the role of water, we have also very recently published the results of the investigation considering the addition of water dimers (n = 2) and trimers (n = 3) to the reactants. Such results are also succinctly addressed before we present our latest and unpublished research endeavors. These consist of two items: the first one addresses a new mechanistic pathway for hydrogen-abstraction in n = 2-4 cases, in which we observe a Grotthuss-like hydrogen shuttling mechanism that interconverts covalent and hydrogen bonds (water molecules are no longer spectators); the second addresses our exploratory calculations of the HO2 + O3 reaction inside a (H2O)20 water cage, where we strive to give a detailed insight of the molecular processes behind the uptake of gas-phase molecules by a water droplet. Supplementary material in the form of one zip file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-60733-5Contribution to the Topical Issue "Atomic Cluster Collisions (7th International Symposium)", edited by Gerardo Delgado Barrio, Andrey Solov'Yov, Pablo Villarreal, Rita Prosmiti.

  15. Crystal morphology of simonkolleite (Zn5(OH)8Cl2.H2O): a SEM study

    International Nuclear Information System (INIS)

    In this paper the morphology of natural and synthetic simonkolleite crystals is investigated. We use an approach of determining the Miller indices of the faces of crystals with electron-microscopic dimensions by comparing their SEM photographs with model images generated by the computer program VESTA. The morphological importance of the crystallographic forms of simonkolleite was estimated on the basis of Bravais–Friedel–Donnay–Harker law and the theory of PBC-vectors. Model images of the crystals were obtained by the introduction of lattice parameters, space groups and the indices of the morphologically important forms. The program VESTA allows for the obtention of projections of the model image in stochastic orientations and for a very precise comparison with the image of the real crystal. It was found that the studied simonkolleite crystals are formed from basal pinacoid {001} and rhombohedrons {101} and {012}. Key words: simonkolleite, crystal morphology, Miller indices

  16. Continuous/Batch Mg/MgH2/H2O-Based Hydrogen Generator

    Science.gov (United States)

    Kindler, Andrew; Huang, Yuhong

    2010-01-01

    A proposed apparatus for generating hydrogen by means of chemical reactions of magnesium and magnesium hydride with steam would exploit the same basic principles as those discussed in the immediately preceding article, but would be designed to implement a hybrid continuous/batch mode of operation. The design concept would simplify the problem of optimizing thermal management and would help to minimize the size and weight necessary for generating a given amount of hydrogen.

  17. TES/Aura L2 H2O Limb V004

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  18. TES/Aura L2 H2O Nadir Special Observation V004

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  19. TES/Aura L2 H2O Nadir Special Observation V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  20. TES/Aura L2 H2O Nadir V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  1. TES/Aura L2 H2O Nadir Special Observation V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  2. TES/Aura L2 H2O Nadir V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  3. TES/Aura L2 H2O Nadir V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  4. TES/Aura L2 H2O Limb V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  5. TES/Aura L2 H2O Nadir Special Observation V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  6. Separation of deuterium by H2/H2O reaction with hydrophobic platinum catalyst

    International Nuclear Information System (INIS)

    The separation performance of a trickle bed exchange column packed with a hydrophobic or waterproof catalyst is related to operating conditions such as hydrogen surface velocity, water flow rate, and temperature. The optimum carrier type and catalyst platinum content were determined. The continuous injection of roughly 103 ppm O2 regenerates the catalyst effectively. The ratio of hydrophobic catalyst to hydrophilic packing is an important factor in increasing the exchange rate in deuterium extraction

  7. Deuterium MR in vivo imaging of the rat eye using 2H2O

    International Nuclear Information System (INIS)

    In vivo deuterium MR imaging (2H MR) was investigated in rats after intraperitoneal administration of deuterated saline, and a dynamic study of the water movement in rat eyes was performed. Deuterium MR imaging was carried out by means of a gradient-echo (GRE) and a spin-echo (SE) pulse sequence. The rat eye was imaged in 2H MR more selectively by SE than by GRE, but a lower signal-to-noise ratio was obtained in 2H MR imaging using the SE sequence. The MR signal intensity of the rat eye was followed by a 3-compartment model, which enabled determination of the flow rate constant of the water in the eye (0.359/min). Deuterium MR imaging is useful to visualize the dynamic change of water in rat eyes using 2H MR at the same magnetic field (2 T) that can also be used for conventional MR imaging in humans. (orig.)

  8. Redetermination of [Pr(NO33(H2O4]·2H2O

    Directory of Open Access Journals (Sweden)

    Roel Decadt

    2012-07-01

    Full Text Available The structure of the title compound, tetraaquatris(nitrato-κ2O,O′praseodymium(III dihydrate, was redetermined. The structure models derived from the previous determinations [Rumanova et al. (1964. Kristallografiya, 9, 642–654; Fuller & Jacobson (1976. Cryst. Struct. Commun. 5, 349–352] were confirmed, but now with all H atoms unambiguously located, revealing a complex O—H...O hydrogen-bonding network, extending throughout the whole structure. In the title compound, the coordination environment of the PrIII atom can best be described as a distorted bicapped square antiprism defined by three bidentate nitrate anions and four water molecules. Additionally, two lattice water molecules are observed in the crystal packing. The title compound is isotypic with several other lanthanide-containing nitrate analogues.

  9. Ice Grain Collisions in Comparison: CO$_2$, H$_2$O and their Mixtures

    CERN Document Server

    Musiolik, Grzegorz; Jankowski, Tim; Wurm, Gerhard

    2016-01-01

    Collisions of ice particles play an important role in the formation of planetesimals and comets. In recent work we showed, that CO$_2$ ice behaves like silicates in collisions. The resulting assumption was that it should therefore stick less efficiently than H$_2$O ice. Within this paper a quantification of the latter is presented. We used the same experimental setup to study collisions of pure CO$_2$ ice, pure water ice and 50\\% mixtures by mass between CO$_2$ and water at 80K, 1 mbar and an average particle size of $\\sim 90 \\mu$m. The results show a strong increase of the threshold velocity between sticking and bouncing with increasing water content. This supports the idea that water ice is favorable for early growth phases of planets in a zone within the H$_2$O and the CO$_2$ iceline.

  10. Cold denaturation and 2H2O stabilization of a staphylococcal nuclease mutant.

    OpenAIRE

    Antonino, L C; Kautz, R. A.; Nakano, T.; Fox, R. O.; Fink, A L

    1991-01-01

    Cold denaturation is now recognized as a general property of proteins but has been observed only under destabilizing conditions, such as moderate denaturant concentration or low pH. By destabilizing the protein using site-directed mutagenesis, we have observed cold denaturation at pH 7.0 in the absence of denaturants in a mutant of staphylococcal nuclease, which we call NCA S28G for a hybrid protein between staphylococcal nuclease and concanavalin A in which there is the point mutation Ser-28...

  11. Radiation-heterogeneous processes in the system RaSiO2+H2O

    International Nuclear Information System (INIS)

    Full text : It is known, that change of the maintenance of radium in radium silicate renders the big influence on their physical and chemical, including adsorption and catalytic properties. However, laws of influence of the maintenance of radium on radiation - heterogeneous processes of decomposition of substances in contact of radium silicates are unknown and represent great value at the decision of problems of radiation catalysis, radiating materiality and at the decision of radio environmental problems. Therefore in given article with this purpose it is investigated the kinetics of radiolytic decomposition of water in contact with radium silicate, depending on the radium maintenance at various temperatures. The received samples have been dried up in dry case under vacuum. Thus, the received results on studying of radiation-catalytic activity of various forms of radium-silicate during radiolysis o f waters (?=300) show, that high catalytic activity has radium silicate with ?=6100 b?/q?. It is established, that radium silicate depending on the maintenance of radium at ?=573 has thermo catalytic activity during decomposition of water. On the basis of these results it is possible to make the assumption, that on a surface of radium - silicate are available various thermo catalytic active centers which become more active at various temperatures. With rise in temperature during thermo catalytic decomposition participate less active centers. Thus at rise in temperature ? 573? at heterogeneous radiolysis of waters at presence of radium silicate occurs thermo catalytic and radiation-thermo catalytic decomposition of water decomposition of water

  12. Crystal structure of NH4[La(SO4)2(H2O)

    OpenAIRE

    Meriem Benslimane; Yasmine Kheira Redjel; Hocine Merazig; Jean-Claude Daran

    2015-01-01

    The principal building units in the crystal structure of ammonium aquabis(sulfato)lanthanate(III) are slightly distorted SO4 tetrahedra, LaO9 polyhedra in the form of distorted tricapped trigonal prisms, and NH4+ ions. The La3+ cation is coordinated by eight O atoms from six different sulfate tetrahedra, two of which are bidentate coordinating and four monodentate, as well as one O atom from a water molecule; each sulfate anion bridges three La3+ cations. These bridging modes result in the fo...

  13. Crystal structure of NH4[La(SO4)2(H2O)

    OpenAIRE

    Benslimane, Meriem; Redjel, Yasmine Kheira; Merazig, Hocine; Daran, Jean-Claude

    2015-01-01

    The principal building units in the crystal structure of ammonium aqua­bis(sulfato)­lanthanate(III) are slightly distorted SO4 tetra­hedra, LaO9 polyhedra in the form of distorted tricapped trigonal prisms, and NH4 + ions. The La3+ cation is coordinated by eight O atoms from six different sulfate tetra­hedra, two of which are bidentate coordinating and four monodentate, as well as one O atom from a water mol­ecule; each sulfate anion bridges three La3+ cations. These bridging modes result in ...

  14. Surface and Electrochemical Behavior of HSLA in Supercritical CO2-H2O Environment

    Energy Technology Data Exchange (ETDEWEB)

    M. Ziomek-Moroz; G. R. Holcomb; J. Tylczak; J. Beck; M. Fedkin; S. Lvov

    2012-01-11

    General corrosion was observed on high strength low alloy carbon steel after electrochemical impedance spectroscopy experiments (EIS) performed in H{sub 2}O saturated with CO{sub 2} at 50 C and 15.2 MPa. However, general and localized were observed on the same material surfaces after the EIS experiments performed in supercritical CO{sub 2} containing approximately 6100 ppmv H{sub 2}O at 50 C and 15.2 MPa. The general corrosion areas were uniformly covered by the FeCO{sub 3}-like phase identified by X-ray diffraction (XRD). In the area of localized corrosion, XRD also revealed FeCO{sub 3}-rich islands embedded in {alpha}-iron. The energy dispersive X-ray (EDX) analysis revealed high concentrations of iron, carbon, and oxygen in the area affected by general corrosion and in the islands formed in the area of localized corrosion. The real and imaginary impedances were lower in H{sub 2}O saturated with CO{sub 2} than those in the supercritical CO{sub 2} containing the aqueous phase indicating faster corrosion kinetics in the former.

  15. Surface Studies of HSLA Steel after Electrochemical Corrosion in Supercritical CO2-H2O Environment

    Energy Technology Data Exchange (ETDEWEB)

    Ziomek-Moroz, M. Holcomb, G. Tylczak, J Beck, J Fedkin, M. Lvov, S.

    2011-10-01

    In aqueous phase saturated with CO2, X-65 sample underwent general corrosion with formation of FeCO3. In supercritical CO2 containing water phase, two major regions are present on the sample surface after the EIS experiment. One region covered with corrosion products identified as FeCO3 and the other containing Fe, oxygen, and carbon-rich islands embedded in metal matrix identified as {alpha}-Fe. Precipitation of FeCO3 from Fe2+ and CO3 2- is responsible for formation of passive layer in oxygen-deficient, CO2 rich aqueous environment. Mechanisms of corrosion degradation occurring in supercritical CO2 as a function. Transport of supercritical CO{sub 2} is a critical element for carbon capture from fossil fuel power plants and underground sequestration. Although acceptable levels of water in supercritical CO{sub 2} (up to {approx} 5 x 10{sup -4}g/dm{sup 3}) have been established, their effects on the corrosion resistance of pipeline steels are not fully known. Moreover, the presence of SO{sub 2}, O{sub 2} impurities in addition to the water can make the fluid more corrosive and, therefore, more detrimental to service materials. Also, in this case, limited data are available on materials performance of carbon steels. to advance this knowledge, other service alloys are being investigated in the high pressure high temperature cell containing impure CO{sub 2} fluids using reliable non-destructive in-situ electrochemical methods. The electrochemical results are being augmented by a number of surface analyses of the corroded surfaces.

  16. 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.

  17. Synthesis and characterization of ZnxHg1-xSeyS1-y quantum dots

    International Nuclear Information System (INIS)

    This article describes the synthesis of highly water-soluble ZnxHg1-xSeyS1-y quantum dots (QDs) in aqueous solution through a simple photo-assisted reaction between ZnSe QDs and mercury(I) nitrate dihydrate [Hg2(NO3)2.2H2O]. In order to deduce the optimal synthesis conditions, we varied several parameters, including the concentrations of mercaptosuccinic acid (MSA) and Hg2(NO3)2.2H2O, the illumination time, and the reaction temperature. When irradiated at temperatures below 80 oC, the ZnSe QDs reacted with the S2- ions formed rapidly from MSA and the Hg2+ ions formed from Hg22+ ions to form ZnxHg1-xSeyS1-y QDs through a process of photo-etching and surface combination. Under different conditions, we prepared a series of ZnxHg1-xSeyS1-y QDs that emit fluorescence at the maximum wavelengths ranging from 405 to 760 nm. Inductively coupled plasma-mass spectrometry and transmission electron microscopy/energy dispersive spectrometry revealed that the content of Hg in the ZnxHg1-xSeyS1-y QDs was greater when the synthesis was conducted at higher temperature. The Zn0.88Hg0.12Se0.44S0.56 QDs exhibit improved photostability than crude ZnSe QDs and possess long lifetimes (τ1 ∼ 38 ns and τ2 ∼ 158 ns).

  18. Об использовании оксалата железа FeC2O4·2H2O для синтеза электродного материала LiFePO4

    OpenAIRE

    Чуриков, А.; Леенсон, И.

    2012-01-01

    В обзоре обобщены литературные сведения о термическом разложении оксалата железа (II) с образованием Fe, FeO, Fe2O3, Fe3O4, Fe3Cи других продуктов. Прослежена историческая эволюция взглядов на пути и механизм термолиза оксалатов. Анализируется современное состояние проблемы с позиции использования соединения FeC2O4·2H2O для синтеза феррофосфата лития LiFePO4 многообещающего катодного материала для литий-ионных аккумуляторов....

  19. PVTx properties of the CO2-H2O and CO2-H2O-NaCl systems below 647 K: assessment of experimental data and thermodynamic models

    Science.gov (United States)

    Hu, Jiawen; Duan, Zhenhao; Zhu, Chen; Chou, I.-Ming

    2007-01-01

    Evaluation of CO2 sequestration in formation brine or in seawater needs highly accurate experimental data or models of pressure–volume–temperature-composition (PVTx) properties for the CO2–H2O and CO2–H2O–NaCl systems. This paper presents a comprehensive review of the experimental PVTx properties and the thermodynamic models of these two systems. The following conclusions are drawn from the review: (1) About two-thirds of experimental data are consistent with each other, where the uncertainty in liquid volumes is within 0.5%, and that in gas volumes within 2%. However, this accuracy is not sufficient for assessing CO2 sequestration. Among the data sets for liquids, only a few are available for accurate modeling of CO2 sequestration. These data have an error of about 0.1% on average, roughly covering from 273 to 642 K and from 1 to 35 MPa; (2) There is a shortage of volumetric data of saturated vapor phase. (3) There are only a few data sets for the ternary liquids, and they are inconsistent with each other, where only a couple of data sets can be used to test a predictive density model for CO2 sequestration; (4) Although there are a few models with accuracy close to that of experiments, none of them is accurate enough for CO2 sequestration modeling, which normally needs an accuracy of density better than 0.1%. Some calculations are made available on www.geochem-model.org.

  20. 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...... of quantum dots, however, results in a large inhomogeneous broadening of quantum dot spectra. Work on self-assembled InGaAs/GaAs quantum dots will be presented. Properties of atom-like single-dot states are investigated optically using high spatial and spectral resolution. Single-dot spectra can be used...

  1. 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...... of quantum dots, however, results in a large inhomogeneous broadening of quantum dot spectra.Work on self-assembled InGaAs/GaAs quantum dots will be presented. Properties of atom-like single-dots states are investigated optically using high spatial and spectral resolution. Single-dot spectra can be used...

  2. CFD Convective Flow Simulation of the Varying Properties of CO2-H2O Mixtures in Geothermal Systems

    OpenAIRE

    Yousefi, S; Atrens, A. D.; Sauret, E.; M. Dahari; Hooman, K.

    2015-01-01

    Numerical simulation of a geothermal reservoir, modelled as a bottom-heated square box, filled with water-CO2 mixture is presented in this work. Furthermore, results for two limiting cases of a reservoir filled with either pure water or CO2 are presented. Effects of different parameters including CO2 concentration as well as reservoir pressure and temperature on the overall performance of the system are investigated. It has been noted that, with a fixed reservoir pressure and temperature, any...

  3. TG-FTIR measurement of CO2-H2O co-adsorption for CO2 air capture sorbent screening

    OpenAIRE

    Smal, I.M.; Yu, Q; Veneman, R.; Fränzel-Luiten, B.; Brilman, D.W.F.

    2014-01-01

    Capturing atmospheric CO2 using solid sorbents is gaining interest. As ambient air normally contains much more (up to 100 times) water than CO2, a selective sorbent is desirable as co-adsorption will most likely occur. In this study, a convenient method based on an TG-FTIR analysis system is developed and used to characterize sorbents for their water and CO2 adsorption capacity when exposed to ambient air. The method allows to determine quantitatively the co-adsorbed amounts of CO2 and water ...

  4. Effect of Kovar alloy oxidized in simulated N2/H2O atmosphere on its sealing with glass

    Institute of Scientific and Technical Information of China (English)

    Dawei Luo; Wenbo Leng; Zhuoshen Shen

    2008-01-01

    The effect of Kovar alloy oxidized in simulated field atmosphere on its sealing with glass was studied in this article. After Kovar plates and pins were preoxidized in N2 with 0℃, 10℃ and 20℃ dew points at 1000℃ for different times, Fe3O4 and Fe2O3 existed in the oxidation products on Kovar surface, and the quantity of Fe2O3 increased with increasing dew point and oxidation time.Then they were sealed with borosilicate glass insulator at 1030℃ for 20 min. The results indicated that the type and quantity of oxidation products would directly influence the quality of glass-to-metal seals. With the increase of oxidation products, gas bubbles in the glass insulator were more serious, the climbing height of glass along the pins was higher, and corrosion of Kovar pins caused from the molten glass was transformed from uniform to the localized.

  5. Alkaline hydrolysis of dimethyl terephthalate in the presence of [LiAl2(OH)6]Cl.2H2O

    International Nuclear Information System (INIS)

    The alkaline hydrolysis of dimethyl terephthalate (DMT) in the presence of [LiAl2(OH)6]Cl has been investigated to demonstrate a possible application of anion exchange facility of layered double hydroxides (LDHs) to control chemical reactions. The results show that (i) in the alkaline hydrolysis of DMT in the presence of [LiAl2(OH)6]Cl, most of the interlayer Cl- of [LiAl2(OH)6]Cl is quickly replaced by OH- in the alkaline solution because the LDH host favors OH- more; (ii) the alkaline hydrolysis of DMT in the presence of [LiAl2(OH)6]Cl is faster than the reaction of DMT and [LiAl2(OH)6]OH; (iii) The hydrolysis of DMT in a buffer solution of pH∼8 takes longer time to reach equilibrium than the alkaline hydrolysis of DMT in the presence of [LiAl2(OH)6]Cl. It is believed that the selective anion exchange chemistry of the LDH plays a key role in storage and controlled release of active reactant, that is, OH-, thus make the hydrolysis proceeds in a controlled way. - Graphical abstract: XRD patterns of the solid products of the alkaline hydrolysis of dimethyl terephthalate (DMT) in the presence of [LiAl2(OH)6]Cl at 70 deg. C halted at different time, which shows that [LiAl2(OH)6]Cl turns out to be [LiAl2(OH)6]OH, and [LiAl2(OH)6]2TP forms gradually. In this reaction, the alkaline hydrolysis of DMT is controlled by replacement of Cl- in [LiAl2(OH)6]Cl by OH-, and subsequent replacement of OH- in [LiAl2(OH)6]OH by terephthalate anion

  6. Iron Thin Films from Fe„CO…5 and FeCp2/H2O under Atmospheric Pressure

    OpenAIRE

    Senocq, François; Duminica, Florin-Daniel; Maury, Francis; Delsol, Thomas; Vahlas, Constantin

    2006-01-01

    Iron layers were first obtained from iron pentacarbonyl in metallorganic chemical vapor deposition MOCVD process under atmospheric pressure, in the temperature range 473–773 K, in a vertical cold wall reactor. Films of good purity were obtained with or without hydrogen as co-reactant, no chemical additives being used. The experiments showed that the velocity of the gas stream and, to a lower extent, the precursor molar fraction are the key parameters to be controlled, in order to monitor f...

  7. Investigation of laser-plasma chemistry in CO-N-2-H2O mixtures using O-18 labeled water

    Czech Academy of Sciences Publication Activity Database

    Ferus, Martin; Matulková, Irena; Juha, Libor; Civiš, Svatopluk

    2009-01-01

    Roč. 472, 1-3 (2009), s. 14-18. ISSN 0009-2614 R&D Projects: GA ČR GA203/06/1278; GA MŠk LA08024; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100523 Keywords : carbon monoxide * plasma * atmosphere Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.291, year: 2009

  8. The reaction of uranium in the U-O2-H2O and U-H2O systems

    International Nuclear Information System (INIS)

    The reaction of uranium in dry air, moist air and oxygen free moisture has been studied thermogravimetrically over the temperature range 105-3250C and at water vapour pressures up to 100 kPa. It has been shown that in dry air the kinetics are complex and appear to result from parallel reactions involving both parabolic and linear rate laws. In oxygen free moisture, linear kinetics were obeyed and a near stoichiometric UO2 reaction product was formed. Oxygen markedly inhibited the moisture reaction at the lower temperatures in the range examined but the degree of inhibition, as shown by weight gain measurements, decreased with increasing temperature such that, at the higher temperatures, there was little difference in reaction rates. At all temperatures, the production of hydrogen was markedly inhibited by the presence of air suggesting that the principal reaction was with free oxygen. However in moist conditions the reaction rate exhibited a dependency on the water vapour pressure according to k α psup(n) where n ∼ 0.3 in air and ∼ 0.5 in oxygen free conditions. The mechanism of the oxidation reaction is discussed. (author)

  9. Atmospheric isoprene ozonolysis: impacts of stabilized Criegee intermediate reactions with SO2, H2O and dimethyl sulfide

    Directory of Open Access Journals (Sweden)

    M. J. Newland

    2015-03-01

    Full Text Available Isoprene is the dominant global biogenic volatile organic compound (VOC emission. Reactions of isoprene with ozone are known to form stabilised Criegee intermediates (SCIs, which have recently been shown to be potentially important oxidants for SO2 and NO2 in the atmosphere; however the significance of this chemistry for SO2 processing (affecting sulfate aerosol and NO2 processing (affecting NOx levels depends critically upon the fate of the SCI with respect to reaction with water and decomposition. Here, we have investigated the removal of SO2 in the presence of isoprene and ozone, as a function of humidity, under atmospheric boundary layer conditions. The SO2 removal displays a clear dependence on relative humidity, confirming a significant reaction for isoprene derived SCI with H2O. Under excess SO2 conditions, the total isoprene ozonolysis SCI yield was calculated to be 0.56 (±0.03. The observed SO2 removal kinetics are consistent with a relative rate constant, k(SCI + H2O/k(SCI + SO2, of 5.4 (±0.8 × 10−5 for isoprene derived SCI. The relative rate constant for k(SCI decomposition/k(SCI + SO2 is 8.4 (±5.0 × 1010 cm−3. Uncertainties are ±2σ and represent combined systematic and precision components. These kinetic parameters are based on the simplification that a single SCI species is formed in isoprene ozonolysis, an approximation which describes the results well across the full range of experimental conditions. Our data indicate that isoprene-derived SCIs are unlikely to make a substantial contribution to gas-phase SO2 oxidation in the troposphere. We also present results from an analogous set of experiments, which show a clear dependence of SO2 removal in the isoprene-ozone system as a function of dimethyl sulfide concentration. We propose that this behaviour arises from a rapid reaction between isoprene-derived SCI and DMS; the observed SO2 removal kinetics are consistent with a relative rate constant, k(SCI + DMS/k(SCI + SO2, of 4.1 (±2.2. This result suggests that SCIs may contribute to the oxidation of DMS in the atmosphere and that this process could therefore influence new particle formation in regions impacted by emissions of unsaturated hydrocarbons and DMS.

  10. Comparative sterilization effectiveness of plasma in O2-H2O2 mixtures and ethylene oxide treatment.

    Science.gov (United States)

    Silva, J M F; Moreira, A J; Oliveira, D C; Bonato, C B; Mansano, R D; Pinto, T J A

    2007-01-01

    We investigated the influence of variable parameters of plasma sterilization and compared its effectiveness with that of ethylene oxide using a reactive ion etching plasma reactor at 13.56 MHz. Gases tested were pure oxygen and oxygen-hydrogen peroxide mixtures in 190/10, 180/20, and 160/40 sccm ratios with constant gas flow at 200 sccm, pressure at 0.100 torr, radio-frequency power at 25 W, 50 W, 100 W, and 150 W, and temperature below 60 degrees C. Ethylene oxide sterilization was performed using 450 mg/L at 55 degrees C, 60% humidity, and -0.65 and 0.60 kgf/cm2 pressure. The biological indicator was Bacillus atrophaeus ATCC 9372, with exposure times of 3 to 120 min. Observed D values were 215.91, 55.55, 9.19, and 2.98 min for pure oxygen plasma at 25 W, 50 W, 100 W, and 150 W, respectively. Oxygen-hydrogen peroxide plasma produced D values of 6.41 min (190/10), 6.47 min (180/20), and 4.02 min (160/40) at 100 W and 1.47 min (190/10), 3.11 min (180/20), and 1.94 min (160/40) at 150 W. Ethylene oxide processes resulted in a D value of 2.86 min. Scanning electron microscopy analyses showed damage to the spore cortex. PMID:17722487

  11. Energy distributions of secondary electrons from Ar, N2, H2O, and H2O with clusters present

    International Nuclear Information System (INIS)

    Crossed beam measurements have been made of the energy spectra of secondary electrons resulting from collisions of 1 keV primary electrons with N2, Ar, H2O, and H2O with clusters present. Only those electrons emitted normal to the primary beams were detected. A thorough description of the apparatus is given

  12. The energy distributions of secondary electrons from Ar, N2, H2O, and H2O with clusters present

    International Nuclear Information System (INIS)

    Crossed beam measurements have been made of the energy spectra of secondary electrons resulting from collisions of 1 keV primary electrons with N2, Ar, H2O, and H2O with clusters present. Only those electrons emitted normal to the primary beams were detected. A thorough description of the apparatus is given

  13. Ni/YSZ pattern anodes fabrication and their microstructure and electrochemical behavior changes in H2-H2O environments

    Science.gov (United States)

    Yao, W.; Croiset, E.

    2013-03-01

    An effective photolithographic process was investigated to fabricate Ni/YSZ pattern anodes using a bi-layer lift-off resist method. Suitable undercut size was found critical for successful pattern fabrication. Effects of Ni thickness, temperature and H2O content on Ni pattern microstructure were evaluated. Ni/YSZ pattern anodes with 0.5 μm thick Ni was tested in dry H2 at 550 °C without significantly changing the TPB line. Ni/YSZ pattern anodes with Ni thickness of 0.8 μm were tested at 550 °C under dry and humidified H2 (3-50% H2O) conditions without TPB line change. At 700 °C, and for 0.8 μm thick patterns, the TPB length showed pronounced change in H2 with 10-50% H2O. Significant increase in TPB length due to holes formation was observed at 800 °C with 3% and 10% H2O. Ni/YSZ pattern anodes with 1.0 μm thick Ni was stable in H2 with 3% H2O in the range 550-800 °C, with TPB line only slightly modified. However, distinct change of TPB line and Ni microstructure was observed with 10-70% H2O above 700 °C. Stabilization of the polarization resistance depends on temperature. To accelerate stabilization of the cell, pre-treatment of the cell in H2 with 3% H2O at 750 °C or 800 °C could be performed.

  14. Preparation of Pt-SDB hydrophobic catalyst used in H2-H2O isotope exchange reaction

    International Nuclear Information System (INIS)

    The preparation of Pt-SDB hydrophobic catalyst is studied, in which platinum as active metal and polystyrene divinylbenzene (SDB) as the carrier. Hydrogen isotope exchange reaction is carried out with Pt-SDB catalyst in counter-current in the trickle bed. The effect of preparing condition on the activity of catalyst is discussed. The results show that the excellent catalyst is obtained by reduced at the temperature of 200 degree C over 8 hours. Hydrophobic catalyst is high activity and stability as the amount of platinum content is 3%, the platinum can reach the economic use with the content of (1-2)%

  15. CFD Convective Flow Simulation of the Varying Properties of CO2-H2O Mixtures in Geothermal Systems

    Directory of Open Access Journals (Sweden)

    S. Yousefi

    2015-01-01

    Full Text Available Numerical simulation of a geothermal reservoir, modelled as a bottom-heated square box, filled with water-CO2 mixture is presented in this work. Furthermore, results for two limiting cases of a reservoir filled with either pure water or CO2 are presented. Effects of different parameters including CO2 concentration as well as reservoir pressure and temperature on the overall performance of the system are investigated. It has been noted that, with a fixed reservoir pressure and temperature, any increase in CO2 concentration leads to better performance, that is, stronger convection and higher heat transfer rates. With a fixed CO2 concentration, however, the reservoir pressure and temperature can significantly affect the overall heat transfer and flow rate from the reservoir. Details of such variations are documented and discussed in the present paper.

  16. CFD convective flow simulation of the varying properties of CO2-H2O mixtures in geothermal systems.

    Science.gov (United States)

    Yousefi, S; Atrens, A D; Sauret, E; Dahari, M; Hooman, K

    2015-01-01

    Numerical simulation of a geothermal reservoir, modelled as a bottom-heated square box, filled with water-CO2 mixture is presented in this work. Furthermore, results for two limiting cases of a reservoir filled with either pure water or CO2 are presented. Effects of different parameters including CO2 concentration as well as reservoir pressure and temperature on the overall performance of the system are investigated. It has been noted that, with a fixed reservoir pressure and temperature, any increase in CO2 concentration leads to better performance, that is, stronger convection and higher heat transfer rates. With a fixed CO2 concentration, however, the reservoir pressure and temperature can significantly affect the overall heat transfer and flow rate from the reservoir. Details of such variations are documented and discussed in the present paper. PMID:25879074

  17. Intercalation behavior of calcium phenylphosphonate dihydrate CaC6H5PO3.2H2O

    Czech Academy of Sciences Publication Activity Database

    Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav

    2010-01-01

    Roč. 66, 3-4 (2010), s. 279-284. ISSN 0923-0750 R&D Projects: GA ČR GA203/08/0208 Institutional research plan: CEZ:AV0Z40500505 Keywords : intercalation * layered phenylphosphonate * amines Subject RIV: CA - Inorganic Chemistry Impact factor: 1.220, year: 2010

  18. Investigation of Laser Plasma Chemistry in CO2-N-2-H2O Using O-18 Labeled Water

    Czech Academy of Sciences Publication Activity Database

    Ferus, Martin; Kubelík, Petr; Juha, Libor; Civiš, Svatopluk

    2009-01-01

    Roč. 39, 3-4 (2009), s. 245-245. ISSN 0169-6149 R&D Projects: GA MŠk LC510; GA MŠk(CZ) LC528; GA ČR GA203/06/1278; GA MŠk LA08024 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z10100523 Keywords : LIDB plasma * atmosphere * isotopes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.053, year: 2009

  19. 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).

  20. 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...

  1. ZnO-dotted porous ZnS cluster microspheres for high efficient, Pt-free photocatalytic hydrogen evolution

    Science.gov (United States)

    Wu, Aiping; Jing, Liqiang; Wang, Jianqiang; Qu, Yang; Xie, Ying; Jiang, Baojiang; Tian, Chungui; Fu, Honggang

    2015-03-01

    The Pt-free photocatalytic hydrogen evolution (PHE) has been the focus in the photocatalysis field. Here, the ZnO-dotted porous ZnS cluster microsphere (PCMS) is designed for high efficient, Pt-free PHE. The PCMS is designed through an easy ``controlling competitive reaction'' strategy by selecting the thiourea as S2- source and Zn(Ac)2.2H2O as Zn source in ethylene glycol medium. Under suitable conditions, one of the PCMS, named PCMS-1, with high SBET specific area of 194 m2g-1, microsphere size of 100 nm and grain size of 3 nm can be obtained. The formation of PCMS is verified by TEM, XAES, XPS, Raman and IR methods. Importantly, a series of the experiments and theoretical calculation demonstrate that the dotting of ZnO not only makes the photo-generated electrons/hole separate efficiently, but also results in the formation of the active catalytic sites for PHE. As a result, the PCMS-1 shows the promising activity up to 367 μmol h-1 under Pt-free condition. The PHE activity has no obvious change after addition 1 wt.% Pt, implying the presence of active catalytic sites for hydrogen evolution in the PCMS-1. The easy synthesis process, low preparation cost of the PCMS makes their large potential for Pt-free PHE.

  2. 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....

  3. SAP Nuclear Competence Centre

    International Nuclear Information System (INIS)

    In this issue we continue and introduce the SAP Nuclear Competence Centre and its head Mr. Igor Dzama. SAP Nuclear Competence Centrum is one of the fi rst competence centres outside ENEL headquarters. It should operate in Slovakia and should have competencies within the whole Enel group. We are currently dealing with the issues of organisation and funding. We are trying to balance the accountability to the NPP directors and to the management of the competence centres at Enel headquarters; we are looking at the relations between the competence centres within the group and defining the services that we will provide for the NPPs. author)

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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.......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....

  10. The Aube centre

    International Nuclear Information System (INIS)

    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.)

  11. Detection of micrometastases in lung cancer with magnetic nanoparticles and quantum dots

    Directory of Open Access Journals (Sweden)

    Wang Y

    2012-05-01

    Full Text Available Yali Wang, Yucheng Zhang*, Zhenwu Du, Mei Wu, Guizhen Zhang* Central Laboratory, China-Japan Union Hospital, Jilin University, Changchun, People’s Republic of China *These authors contributed equally to this workAbstract: Detection of micrometastases plays an important role in early-stage and recurrent cancer diagnosis. In the study, a new method of screening micrometastases of lung cancer in peripheral blood by magnetic nanoparticles (MNPs and quantum dots (QDs was developed to achieve early diagnosis and recurrence prevention. MNPs were prepared by combining miniemulsion polymerization and Stöber coating methods. QDs were prepared by using Cd(Ac2 • 2H2O and oxygen-free NaHTe with thioglycolic acid as the stabilizer. The carbodiimide-mediated condensation method was used to couple pan-cytokeratin (pan-ck antibody (Ab to the surface of the MNPs, and Lunx and SP-A Abs to the surface of the QDs. After four kinds of epithelial tumor cells were enriched by MNPs coupled with pan-ck Ab (MNP-pan-ck, lung cancer cells A549 and SPC-A-1 were successfully identified by QDs with double-labeled Abs. Finally, 32 patients with non-small cell lung cancer (NSCLC were collected, out of 26 cases with the enriched circulating tumor cells (CTCs, 21 cases were successfully identified by QDs. Therefore, a new method was established in which MNP-pan-ck collected CTCs and QDs with double-labeled Abs could be used simultaneously to identify CTCs from NSCLC patients.Keywords: micrometastases, lung cancer, magnetic nanoparticles, quantum dots, Lunx, SP-A

  12. 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)

  13. 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.

  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. 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.

  16. 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

  17. Quantum Dots: Theory

    OpenAIRE

    Vukmirovic, Nenad

    2010-01-01

    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.

  18. Advanced CANDU control centre

    International Nuclear Information System (INIS)

    The CANDU 9 design is based upon the 900 MWe class Darlington station in Canada, which is among the world leading nuclear power stations for capacity factor with low operation, maintenance and administration costs. The CANDU 9 design provides an advanced control centre with enhanced operations features. The advanced AECL control centre design includes the proven functionality of existing CANDU control centres, those implementable characteristics identified by systematic design combined with a human factors analysis of operations requirements and features needed to improve station operability which are made possible by the application of current technology. The design strategy is to preserve the general main control room operations staff work area as unchanged as possible to facilitate the inclusion of past features and operational experience while incorporating operability improvements. The author will present those features of the advanced CANDU control centre which facilitates improved operability capabilities. As well, aspects of the design process utilized, application of simulation technology and conclusions regarding this design approach will be reviewed

  19. Desacralization of Sokol Centres

    Czech Academy of Sciences Publication Activity Database

    Švácha, Rostislav

    Ljubljana : Založba ZRC, 2015 - (Lavrič, A.; Lazarini, F.; Murovec, B.), s. 277-290 ISBN 978-961-254-873-5. - ( Opera Instituti Artis Historiae) Institutional support: RVO:68378033 Keywords : architecture * Sokol centres Subject RIV: AL - Art, Architecture, Cultural Heritage

  20. 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.

  1. The GSO Data Centre

    CERN Document Server

    Paletou, F; Génot, V; Rouillard, A; Petit, P; Palacios, A; Caux, E; Wakelam, V

    2015-01-01

    Hereafter we describe the activities of the $Grand \\, Sud-Ouest$ Data Centre operated for INSU/CNRS by the OMP-IRAP and the Universit\\'e Paul Sabatier (Toulouse), in a collaboration with the OASU-LAB (Bordeaux) and OREME-LUPM (Montpellier).

  2. 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...

  3. DGNB certified Healthcare Centres

    DEFF Research Database (Denmark)

    Brunsgaard, Camilla; Larsen, Tine Steen

    2015-01-01

    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 in an...... the architect, the construction engineer, the plumbing engineer etc. which overlap professional field just like other disciplines. Secondly, the general conception is that DGNB brings in limited new things into the project, but it gives a common notion of sustainability which usually can be discussed...... Healthcare Centres, which was certified as office buildings, however more traditional office buildings might differ en experience with DGNB....

  4. 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.

  5. International Data Centre (IDC)

    International Nuclear Information System (INIS)

    The presentation outlines the International Data Centre (Indc) mission, objective and historical background. The Indc progressive commissioning and organizational plans are presented on charts. The IMS stations providing data to Indc operations and the global communication infrastructure are plotted on world maps. The various types of IMS data are thus listed as seismic, hydroacoustic, infrasound and radionuclide. Finally Indc products and services together with its main achievements are listed

  6. Quantum Dots for Biophotonics

    OpenAIRE

    Ken-Tye Yong

    2012-01-01

    This theme issue provides an excellent collection of reviews and original research articles on the study of various bioconjugated quantum dot formulations for diagnostics and therapy applications using biophotonic imaging and sensing approaches.

  7. 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

  8. 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...

  9. The DESY Grid Centre

    International Nuclear Information System (INIS)

    DESY is one of the world-wide leading centers for research with particle accelerators, synchrotron light and astroparticles. DESY participates in LHC as a Tier-2 center, supports on-going analyzes of HERA data, is a leading partner for ILC, and runs the National Analysis Facility (NAF) for LHC and ILC in the framework of the Helmholtz Alliance, Physics at the Terascale. For the research with synchrotron light major new facilities are operated and built (FLASH, PETRA-III, and XFEL). DESY furthermore acts as Data-Tier1 centre for the Neutrino detector IceCube. Established within the EGI-project DESY operates a grid infrastructure which supports a number of virtual Organizations (VO), incl. ATLAS, CMS, and LHCb. Furthermore, DESY hosts some of HEP and non-HEP VOs, such as the HERA experiments and ILC as well as photon science communities. The support of the new astroparticle physics VOs IceCube and CTA is currently set up. As the global structure of the grid offers huge resources which are perfect for batch-like computing, DESY has set up the National Analysis Facility (NAF) which complements the grid to allow German HEP users for efficient data analysis. The grid infrastructure and the NAF use the same physics data which is distributed via the grid. We call the conjunction of grid and NAF the DESY Grid Centre. In the contribution to CHEP2012 we will in depth discuss the conceptional and operational aspects of our multi-VO and multi-community Grid Centre and present the system setup. We will in particular focus on the interplay of Grid and NAF and present experiences of the operations.

  10. The DESY Grid Centre

    Science.gov (United States)

    Haupt, A.; Gellrich, A.; Kemp, Y.; Leffhalm, K.; Ozerov, D.; Wegner, P.

    2012-12-01

    DESY is one of the world-wide leading centers for research with particle accelerators, synchrotron light and astroparticles. DESY participates in LHC as a Tier-2 center, supports on-going analyzes of HERA data, is a leading partner for ILC, and runs the National Analysis Facility (NAF) for LHC and ILC in the framework of the Helmholtz Alliance, Physics at the Terascale. For the research with synchrotron light major new facilities are operated and built (FLASH, PETRA-III, and XFEL). DESY furthermore acts as Data-Tier1 centre for the Neutrino detector IceCube. Established within the EGI-project DESY operates a grid infrastructure which supports a number of virtual Organizations (VO), incl. ATLAS, CMS, and LHCb. Furthermore, DESY hosts some of HEP and non-HEP VOs, such as the HERA experiments and ILC as well as photon science communities. The support of the new astroparticle physics VOs IceCube and CTA is currently set up. As the global structure of the grid offers huge resources which are perfect for batch-like computing, DESY has set up the National Analysis Facility (NAF) which complements the grid to allow German HEP users for efficient data analysis. The grid infrastructure and the NAF use the same physics data which is distributed via the grid. We call the conjunction of grid and NAF the DESY Grid Centre. In the contribution to CHEP2012 we will in depth discuss the conceptional and operational aspects of our multi-VO and multi-community Grid Centre and present the system setup. We will in particular focus on the interplay of Grid and NAF and present experiences of the operations.

  11. Formulating CdSe quantum dots for white light-emitting diodes with high color rendering index

    International Nuclear Information System (INIS)

    Generation of white light using CdSe quantum dots (QDs) alone presents exciting possibilities for solid state lighting technology. In this work, Cd(Ac)2·2H2O and Na2SeSO3 are used as precursors to synthesize CdSe-QDs with an average diameter ranging from 2.77 to 4.65 nm at the low temperature from 60 to 180 °C. Smaller CdSe-QDs with an average diameter of 2.29 nm are got by an oxidation etching process using H2O2 as oxidant. The structural and optical properties of these QDs are investigated and proper formulation of CdSe QDs with various sizes is carefully designed to achieve white light with a high color rendering index (CRI). It is observed for the first time that the as-prepared white light-emitting diodes from single CdSe-QDs show the Commission Inernationale del’Eclairage coordinate (CIE) of (0.30,0.34) very close to that (0.33,0.33) of pure white light and a high CRI of 84. Owing to these advantages, the as-prepared white light-emitting diodes from a single compound are promising for lighting applications. - Highlights: • CdSe-quantum dots (QDs) with a continuously changing size from 2.31 to 4.74 nm are prepared. • The obtained CdSe-QDs emit lights with tunable colors in the whole visible range. • The obtained mixture sample generates white light with a high color rendering index of 84. • The sample yields white light with the CIE coordinate (0.30, 0.34) very close to that of pure white light

  12. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    After many years of urban growth Danish downtowns are facing some important choices. Shall the stake one-sidedly be on the town centres as driving forces for growth and 'city marketing', or do they still have a role to play in a broader socio-economic context? In the paper we look back on eight...... 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...

  13. 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...

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

    OpenAIRE

    Somsak Panyakeow

    2010-01-01

    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 late...

  15. 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...

  16. [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

  17. Update on System Coordination Centre

    International Nuclear Information System (INIS)

    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. 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...

  19. 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.

  20. Quantum dot cascade laser

    OpenAIRE

    Zhuo, Ning; Liu, Feng Qi; Zhang, Jin Chuan; Wang, Li Jun; Liu, Jun Qi; Zhai, Shen Qiang; Wang, Zhan Guo

    2014-01-01

    We demonstrated an unambiguous quantum dot cascade laser based on InGaAs/GaAs/InAs/InAlAs heterostructure by making use of self-assembled quantum dots in the Stranski-Krastanow growth mode and two-step strain compensation active region design. The prototype generates stimulated emission at λ ~ 6.15 μm and a broad electroluminescence band with full width at half maximum over 3 μm. The characteristic temperature for the threshold current density within the temperature range of 82 to 162 K is up...

  1. 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

  2. From Human-Centred to Human-Context centred Approach

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    The article presents and discusses various human centred design approaches . In addtion it suggests a way to use narrative and numeric simulation methods in a combined approach to meet the challenges of sustainable development with a human-context centred approach....

  3. Analysis of Cl center dot center dot center dot Cl and C-H center dot center dot center dot Cl intermolecular interactions involving chlorine in substituted 2-chloroquinoline derivatives

    OpenAIRE

    Hathwar, Venkatesha R.; Roopan, Mohana S; R. Subashini; Khan, Nawaz F; Row, Guru TN

    2010-01-01

    Six crystal structures of substituted 2-chloroquinoline derivatives have been analysed to evaluate the role of Cl atom as a self recognizing unit resulting in the formation of Cl center dot center dot center dot Cl and C-H center dot center dot center dot Cl interactions to generate supramolecular assembly in the solid state. The features of Type I and Type II geometries associated with Cl center dot center dot center dot Cl interactions have been analysed to show directional preferences lead...

  4. Energy Centre Bratislava

    International Nuclear Information System (INIS)

    Energy Centre Bratislava (ECB) is a non-governmental, not-for-profit organization initiating and promoting development and exploitation of energy efficient processes and technologies, use of alternative and renewable energy sources and reduction of energy use impact on environment. ECB was founded in 1993 by European Commission and Upper Austrian Energy Saving Association in the frame of THERMIE program. or the eleven years of the ECB existence, it maintains a rapid growth rate through expansion of its client base and development of its activities. It is one of the few independent institutions working in energy sector of Slovakia. Due in part to these facts and the number of its activities, the ECB has become a generally recognized partner and has achieved an outstanding reputation. It has given advice to governments, institutions, organizations and the European Commission on the formulation of energy policies and the development and implementation of energy plans at a regional, national and European Union level. The principal goal of ECB activities is the promotion and support measures and activities aimed at increasing energy efficiency and improving environmental protection in Slovakia. The objective of the ECB is likewise to contribute to increasing of public energy awareness. ECB plays an active part in transferring innovative technologies and supporting the implementation of concrete projects,activities and legislative changes. The methods used to fulfill this goal include activities in some fields are reviewed. Main previous and current projects of ECB are presented

  5. Thailand's nuclear research centre

    International Nuclear Information System (INIS)

    The Office of Atomic Energy for Peace, Thailand, is charged with three main tasks, namely, Nuclear Energy development Plan, Utilization of Nuclear Based technology Plan and Science and Technology Plan. Its activities are centred around the research reactor TRR-1/M1. The main areas of contribution include improvement in agricultural production, nuclear medicine and nuclear oncology, health care and nutrition, increasing industrial productivity and efficiency and, development of cadre competent in nuclear science and technology. The office also has the responsibility of ensuring nuclear safety, radiation safety and nuclear waste management. The office has started a new project in 1997 under which a 10 MWt research reactor, an isotope production facility and a waste processing and storage facility would be set up by General Atomic of USA. OAEP has a strong linkage with the IAEA and has been an active participant in RCA programmes. In the future OAEP will enhance its present capabilities in the use of radioisotopes and radiation and look into the possibility of using nuclear energy as an alternative energy resource. (author)

  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. 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...

  8. Colloidal Double Quantum Dots

    Science.gov (United States)

    2016-01-01

    Conspectus 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

  9. 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

  10. CANDU 9 Control Centre Mockup

    International Nuclear Information System (INIS)

    This paper provides a summary of the design process being followed, the benefits of applying a systematic design using human factors engineering, presents an overview of the CANDU 9 control centre mockup facility, illustrates the control centre mockup with photographs of the 3D CADD model and the full scale mockup, and provides an update on the current status of the project. (author)

  11. 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.

  12. The Aube centre. 1997 statement

    International Nuclear Information System (INIS)

    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.)

  13. Hole centres in magnesium oxide

    International Nuclear Information System (INIS)

    When magnesium oxide crystals are exposed to ionizing radiation the electron-loss (hole) centres are normally identified as O·- ions. In this paper, I examine the EPR evidence for this, and compare the data with those for the hole centres in alkali- halides (VK centres). The latter are clearly σ* radical anions, such as F.-F-.The analogous centre in MgO is O.-O3-, which does not seem to have been considered. The results compare well, suggesting that the O·- centres are really O.-O3- radicals. In particular, the 17O data for the oxygen centre and the 19F data for F2·- give similar estimates of the 2s and 2p character of the orbitals on oxygen and fluorine, suggesting that the spin-density on oxygen is ca. 50%. The exception is the direction of the principal axes of these centres, which are quite different from each other. It is suggested that the primary hole-centres in MgO migrate by electron transfer to neighbouring cation vacancies where they are stable, and that at these sites the (1, 0, 0) directions are most favourable for σ- bonding

  14. CMCC Data Distribution Centre

    Science.gov (United States)

    Aloisio, Giovanni; Fiore, Sandro; Negro, A.

    2010-05-01

    The CMCC Data Distribution Centre (DDC) is the primary entry point (web gateway) to the CMCC. It is a Data Grid Portal providing a ubiquitous and pervasive way to ease data publishing, climate metadata search, datasets discovery, metadata annotation, data access, data aggregation, sub-setting, etc. The grid portal security model includes the use of HTTPS protocol for secure communication with the client (based on X509v3 certificates that must be loaded into the browser) and secure cookies to establish and maintain user sessions. The CMCC DDC is now in a pre-production phase and it is currently used only by internal users (CMCC researchers and climate scientists). The most important component already available in the CMCC DDC is the Search Engine which allows users to perform, through web interfaces, distributed search and discovery activities by introducing one or more of the following search criteria: horizontal extent (which can be specified by interacting with a geographic map), vertical extent, temporal extent, keywords, topics, creation date, etc. By means of this page the user submits the first step of the query process on the metadata DB, then, she can choose one or more datasets retrieving and displaying the complete XML metadata description (from the browser). This way, the second step of the query process is carried out by accessing to a specific XML document of the metadata DB. Finally, through the web interface, the user can access to and download (partially or totally) the data stored on the storage device accessing to OPeNDAP servers and to other available grid storage interfaces. Requests concerning datasets stored in deep storage will be served asynchronously.

  15. Chemoselective Reductive Amination of Carbonyl Compounds for the Synthesis of Tertiary Amines Using SnCl2·2H2O/PMHS/MeOH.

    Science.gov (United States)

    Nayal, Onkar S; Bhatt, Vinod; Sharma, Sushila; Kumar, Neeraj

    2015-06-01

    Stannous chloride catalyzed chemoselective reductive amination of a variety of carbonyl compounds with aromatic amines has been developed for the synthesis of a diverse range of tertiary amines using inexpensive polymethylhydrosiloxane as reducing agent in methanol. The present method is also applicable for the synthesis of secondary amines including heterocyclic ones. PMID:25938581

  16. Nano structured porous anodized aluminium oxide by using C2H2O4 for electronic applications: Study of the cell potential effects on formation of porous alumina

    International Nuclear Information System (INIS)

    In this research, a nano porous anodized aluminium oxide AAO thin film was successfully grown onto oxide layer on silicon substrate. The anodization of Si/ SiO2/ Al substrate was conducted in a vigorous stirring oxalic acid bath solution. The rate of growth, morphology and also the kinetic study of the AAO thin film were investigated. The resulting array, pores structure and pores density of AAO strongly depends on an applied voltage of the anodizing process. (author)

  17. Reduction of Pertechnetate By Acetohydroxamic Acid: Formation of [tc**II(NO)(AHA)(2)(H(2)O)]**+ And Implications for the UREX Process

    Energy Technology Data Exchange (ETDEWEB)

    Gong, C.-M.S.; Lukens, W.W.; Poineau, F.; Czerwinski, K.R.

    2009-05-18

    Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the X-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry and the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but it may be augmented by some products of the reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex ([Tc{sup II}(NO)(AHA){sub 2}H{sub 2}O]{sup +}, 1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent: potentiometric-spectrophotometric titration studies indicate a single species from pH 4 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The potential formation of 1 during reprocessing may strongly impact the fate of technetium in the nuclear fuel cycle.

  18. Application of Solid oxide proton-conducting electrolytes for amperometric analysis of hydrogen in H2+N2+H2O gas mixtures

    International Nuclear Information System (INIS)

    Highlights: • Novel amperometric hydrogen sensors based on proton conducting solid electrolytes have been developed. • It was found that, CaZr0.90Sc0.10O3 is suitable for the analysis of gas mixtures with low hydrogen content. • La0.95Sr0.05YO3 is suitable for the analysis of gas mixtures with medium and high (up to 100%) hydrogen content. - Abstract: Amperometric hydrogen sensors based on proton-conducting solid electrolytes of La0.95Sr0.05YO3, CaTi0.95Sc0.05O3 and CaZr0,9Sc0.1O3 compositions are prepared and investigated in the present work. The influence of the sensor design on its own characteristics is also examined. It is shown that a solid electrolyte used in the form of discs with cavities significantly simplifies the design of this type of sensors. A sensor based on La0.95Sr0.05YO3 electrolyte with fully sealed junction between discs is suitable for the analysis of mixtures with high H2 content. It is found that by increasing H2 content from 10 to 98% the limiting current increases from 0.25 to 2.25 mA (at 750 mV). It is also found that the sensor based on La0.95Sr0.05YO3 with discs sealed in two points as well as the sensor based on CaZr0,9Sc0.1O3 with fully sealed junction are suitable for the analysis of mixtures with low H2 content (0.5-2%). For the above cases, the limiting current at 2% H2 reaches 3.5 and 0.5 mA (at 750 mV), respectively. CaTi0.95Sc0.05O3 is not suitable to be used as a hydrogen sensor. In all the examined systems, steam content does not affect sensors’ behavior and high operating temperatures (850 °C) increase the range of sensors’ hydrogen measuring concentration capacity

  19. Structure of a new adduct between telluric acid and a condensed phosphate: K4P4O12.Te(OH)6.2H2O

    International Nuclear Information System (INIS)

    Tetrapotassium cyclo-tetraphosphate-tellurium hexahydroxide-water (1/1/2), Mr=737.96, monoclinic, C2/c, a=9.731(5), b=11.43(1), c=17.16(1) A, β=99.45(5)0, V=1883(2) A3, Z=4, Dm not measured, Dx=2.598 Mg m-3, λ(AgK anti α)=0.5608 A, μ=1.51 mm-1, F(000)=1432, T=293 K, final R value 0.024 for 2353 independent reflexions. Planes of Te(OH)6 groups at z=0.0 and 0.5 alternate with planes of P4O12 ring anions at z=0.25 and 0.75. The set of hydrogen bonds, which involves H2O molecules as well as P4O12 and Te(OH)6 groups, spreads in a one-dimensional way along the b direction. The P4O12 rings have twofold symmetry. (orig.)

  20. Hydrogen peroxide generated by an atmospheric He-O2-H2O flowing post-discharge: production mechanisms and absolute quantification

    CERN Document Server

    Dufour, Thierry; De Vos, Caroline; Reniers, F

    2016-01-01

    An atmospheric plasma torch has been supplied with a gaseous mixture of helium, water vapour and/or oxygen to study the production of reactive species within its flowing post-discharge, in particular hydrogen peroxide. The mechanisms responsible for the production of H2O2 have been investigated by correlating measurements of mass spectrometry and absorption photospectrometry. An absolute quantification of H2O2 has also been achieved and indicated that for 5 mmol of water vapour injected in the He-H2O discharge, approximately 9.5 mol of H2O2 were produced in post-discharge.

  1. Rhombohedral calcite precipitation from CO2-H2O-Ca(OH)2 slurry under supercritical and gas CO2 media

    CERN Document Server

    Montes-Hernandez, German; Geoffroy, Nicolas; Charlet, Laurent; Pironon, Jacques

    2008-01-01

    The formation of solid calcium carbonate (CaCO3) from aqueous solutions or slurries containing calcium and carbon dioxide (CO2) is a complex process of considerable importance in the ecological, geochemical and biological areas. Moreover, the demand for powdered CaCO3 has increased considerably recently in various fields of industry. The aim of this study was therefore to synthesize fine particles of calcite with controlled morphology by hydrothermal carbonation of calcium hydroxide at high CO2 pressure (initial PCO2=55 bar) and at moderate and high temperature (30 and 90 degrees C). The morphology of precipitated particles was identified by transmission electron microscopy (TEM/EDS) and scanning electron microscopy (SEM/EDS). In addition, an X-ray diffraction analysis was performed to investigate the carbonation efficiency and purity of the solid product. Carbonation of dispersed calcium hydroxide in the presence of supercritical (PT=90 bar, T=90 degrees C) or gaseous (PT=55 bar, T=30 degrees C) CO2 led to t...

  2. Dissolution of ettringite in presence of CaO-SiO2-H2O gel at Ca/Si>1

    International Nuclear Information System (INIS)

    This paper presents the dissolution of ettringite (AFt) in presence of calcium silicate hydrate (C-S-H) gel at Ca/Si>1 for improving the reliability of the long-term safety assessment of radioactive waste disposal. In this work, dissolution experiments were performed using ICP-AES in C-S-H gel at Ca/Si=1.0, 1.2 and 1.47 coexisting with AFt of which amount was 5% of mol corresponding to each C-S-H gel. Individual experiments for each amount of AFt were also carried out for comparison between the aqueous concentrations in both systems. In C-S-H gel coexisting with AFt system, SO42- total concentrations arising due to the dissolution of AFt were observed to be a function of Ca/Si ratio in C-S-H gel. Aqueous AI(OH)4- concentration was not measured by ICP-AES indicating that Al(OH)4- has more interaction than SO42- with C-S-H gel. The variations of these concentrations in C-S-H gel coexisting with AFt system may be due to the ionic substitution between their structures and also adsorptions on C-S-H gel mainly. (author)

  3. The thermal stability of sideronatrite and its decomposition products in the system Na2O-Fe2O3-SO2-H2O

    Science.gov (United States)

    Ventruti, Gennaro; Scordari, Fernando; Della Ventura, Giancarlo; Bellatreccia, Fabio; Gualtieri, Alessandro F.; Lausi, Andrea

    2013-09-01

    The thermal stability of sideronatrite, ideally Na2Fe3+(SO4)2(OH)·3(H2O), and its decomposition products were investigated by combining thermogravimetric and differential thermal analysis, in situ high-temperature X-ray powder diffraction (HT-XRPD) and Fourier transform infrared spectroscopy (HT-FTIR). The data show that for increasing temperature there are four main dehydration/transformation steps in sideronatrite: (a) between 30 and 40 °C sideronatrite transforms into metasideronatrite after the loss of two water molecules; both XRD and FTIR suggest that this transformation occurs via minor adjustments in the building block. (b) between 120 and 300 °C metasideronatrite transforms into metasideronatrite II, a still poorly characterized phase with possible orthorhombic symmetry, consequently to the loss of an additional water molecule; X-ray diffraction data suggest that metasideronatrite disappears from the assemblage above 175 °C. (c) between 315 and 415 °C metasideronatrite II transforms into the anhydrous Na3Fe(SO4)3 compound. This step occurs via the loss of hydroxyl groups that involves the breakdown of the [Fe3+(SO4)2(OH)]{∞/2-} chains and the formation of an intermediate transient amorphous phase precursor of Na3Fe(SO4)3. (d) for T > 500 °C, the Na3Fe(SO4)3 compound is replaced by the Na-sulfate thenardite, Na2SO4, plus Fe-oxides, according to the Na3Fe3+(SO4)3 → 3/2 Na2(SO4) + 1/2 Fe2O3 + SOx reaction products. The Na-Fe sulfate disappears around 540 °C. For higher temperatures, the Na-sulfates decomposes and only hematite survives in the final product. The understanding of the thermal behavior of minerals such as sideronatrite and related sulfates is important both from an environmental point of view, due to the presence of these phases in evaporitic deposits, soils and sediments including extraterrestrial occurrences, and from the technological point of view, due to the use of these materials in many industrial applications.

  4. Structural determination; vibration study and thermal decomposition of [C5H6N5]2SeO4ṡ2H2O

    Science.gov (United States)

    Ben Hassen, C.; Boujelbene, M.; Mhiri, T.

    2015-01-01

    The present paper reports the chemical synthesis, structure study, thermal analysis, and vibrational properties of new hybrid compound called: bis (adeninium) selenate bihydrates. It is crystallized in the triclinic system with P-1 space group and the following parameters a = 7.804(5) Å; b = 9.686 (5) Å; c = 11.771 (5) Å; α = 84.421(5)°; ß = 77.556(5)°; γ = 81.186 (5)°; Z = 2 and V = 856.7(8) Å3. The structure is built up from tunnels containing all the components of the structure and following to the c axis, linked via three types of hydrogen bonds (Nsbnd H…O, Nsbnd H…N and Osbnd H…O). The thermal decomposition of precursors studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), indicate the existence of two mass loss region correspond to dehydration and degradation of the title compound, respectively. The existence of vibrational modes correspond to the organic and inorganic groups and water molecular are identified by the IR and Raman spectroscopy in the frequency ranges 400-4000 and 300-1600 cm-1, respectively.

  5. Spatiotemporal variations in growing season exchanges of CO2, H2O,and sensible heat in agricultural fields of the Southern GreatPlains

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Billesbach, David P.; Berry, Joseph A.; Riley,William J.; Torn, Margaret S.

    2007-06-13

    Climate, vegetation cover, and management create fine-scaleheterogeneity in unirrigated agricultural regions, with important but notwell-quantified consequences for spatial and temporal variations insurface CO2, water, and heat fluxes. We measured eddy covariance fluxesin seven agricultural fields--comprising winter wheat, pasture, andsorghum--in the U.S. Southern Great Plains (SGP) during the 2001-2003growing seasons. Land-cover was the dominant source of variation insurface fluxes, with 50-100 percent differences between fields planted inwinter-spring versus fields planted in summer. Interannual variation wasdriven mainly by precipitation, which varied more than two-fold betweenyears. Peak aboveground biomass and growing-season net ecosystem exchange(NEE) of CO2 increased in rough proportion to precipitation. Based on apartitioning of gross fluxes with a regression model, ecosystemrespiration increased linearly with gross primary production, but with anoffset that increased near the time of seed production. Because theregression model was designed for well-watered periods, it successfullyretrieved NEE and ecosystem parameters during the peak growing season,and identified periods of moisture limitation during the summer. Insummary, the effects of crop type, land management, and water limitationon carbon, water, and energy fluxes were large. Capturing the controllingfactors in landscape scale models will be necessary to estimate theecological feedbacks to climate and other environmental impactsassociated with changing human needs for agricultural production of food,fiber, and energy.

  6. Studies in the system MgO-SiO2-CO2-H2O(I): The activity-product constant of chrysotile

    Science.gov (United States)

    Hostetler, P.B.; Christ, C.L.

    1968-01-01

    Chrysotile dissolves congruently in water according to the reaction: Mg3Si2O6(OH)4c + 5H2Ol = 3Mgaq2+ + 6OHaq- + 2H4SiO4aq. Experimental determination of the activity-product constant of chrysotile, Kchr = [Mg2+]3[OH-]6[H4SiO4aq]2, at 90??C, yields the value of Kchr = 10-49.2 ?? 100.5. A synthetic sample and a natural sample from New Idria, California, were used in the determination. Values of Kchr were calculated for temperatures ranging from 0??C to 200??C, using the thermochemical data of King et al. (1967) for chrysotile and antigorite, various solubility data for silica, and ionic partial molal heat capacities estimated by the method of criss and Cobble (1964a). Kchr is 10-54.1 at 0??C, rises to a maximum value of 10-48.5 at approximately 135??C, and is 10-49.1 at 200??C (all values for the three-phase system, chrysotile plus solution plus vapor). The calculated 90??C value is 10-49.1, in excellent agreement with the experimental value; for 25??C, the calculated value is 10-50.8. ?? 1968.

  7. Oxidation mechanisms of materials for heat exchanging components in CO 2 /H 2 O-containing gases relevant to oxy-fuel

    OpenAIRE

    Olszewski, Tomasz

    2012-01-01

    In the context of CO2 emission reduction, the oxy-fuel technology provides a promising option applicable in centralized energy production. This technology is based on pulverized coal combustion with pure oxygen instead of air. Different from the conventional systems, metallic heat exchanging components in the oxy-fuel plants will be subjected to service environments containing high amounts of CO2 and H2O. In the present study the oxidation behaviour of selected ferritic/martensitic and austen...

  8. Synthesis of Chitosan-Grafted-Poly (Methyl Methacrylate) with Fentons Reagent (Fe2+ - H2O2) as a Redox Initiator

    International Nuclear Information System (INIS)

    Graft copolymerization of poly(methyl methacrylate) (PMMA) onto chitosan fiber has been successfully carried out using Fentons Reagent which is consisted of hydrogen peroxide (H2O2) as initiator and ferrous ammonium sulphate (FAS) as co-catalyst under inert atmosphere in an aqueous medium. The PMMA homopolymer formed during the reaction was removed from the grafted copolymer by Soxhlet extraction using acetone as the solvent. The grafting percentage and efficiency obtained were 449.16 % and 85.94 %, respectively. The maximum grafting percentage and efficiency were achieved when 0.3 g chitosan copolymerized with 3 mL monomer at 70 degree Celsius for 120 minutes with [FAS] = 6 x 10-5 M, [H2O2] = 6 x 10-3 M and 8 mL water. The grafted copolymers were characterized by using FTIR, DSC, TGA and SEM analysis. The presence of absorbance band at 1724 cm-1 provided strong evidence of grafting. (author)

  9. Ab initio studies of O2-(H2O)n and O3-(H2O)n anionic molecular clusters, n≤12

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Kurtén, T.; Enghoff, Martin Andreas Bødker;

    2011-01-01

    An ab initio study of gaseous clusters of O2− and O2− with water is presented. Based on thorough scans of configurational space, we determine the thermodynamics of cluster growth. The results are in good agreement with benchmark computational methods and existing experimental data. We find...

  10. Ab initio studies of O-2(-) (H2O)(n) and O-3(-) (H2O)(n) anionic molecular clusters, n

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Kurten, T.; Enghoff, Martin Andreas Bødker;

    2011-01-01

    An ab initio study of gaseous clusters of O-2(-) and O-3(-) with water is presented. Based on thorough scans of configurational space, we determine the thermodynamics of cluster growth. The results are in good agreement with benchmark computational methods and existing experimental data. We find...

  11. Structures and characterization of [Zn(n-chlorosalicylato)2(N-methylnicotinamide)2(H2O)2] (n = 4 or 5) ligand isomers

    Czech Academy of Sciences Publication Activity Database

    Bujdošová, Z.; Györyová, K.; Melník, M.; Koman, M.; Kovářová, Jana

    2011-01-01

    Roč. 41, č. 4 (2011), s. 443-448. ISSN 1074-1542 Institutional research plan: CEZ:AV0Z40500505 Keywords : structure * chlorosalicylate * zinc(II) Subject RIV: CC - Organic Chemistry Impact factor: 0.566, year: 2011

  12. Molecular Structure and Properties of a Novel Acylhydrazone (C14H14O6N4)·HCON(CH3)2.2H2O

    Institute of Scientific and Technical Information of China (English)

    CHEN Feng-ying; WU Wang-ting; LI Heng-xin; HE Shui-yang; WEN Zhen-yi; LI Jia-xing

    2012-01-01

    Abstract [N-(Propionic acid)] terephthalal acyl dihydrazone(H4L) was synthesized and characterized by element analysis,IR,1H NMR and MS.The theoretical studies on H4L were carried out at HF/6-31+G(d) and B3LYP/6-3 1+G(d) levels.The main decomposition stage of it was studied with IR track.The kinetic parameters[the apparent activation energy(Ea) and pre-exponential constant(A) of the first and second stages of decomposition reaction] were obtained by Kissinger and Ozawa's methods.Furthermore,the antimicrobial activity of H4L against wheat rust was investigated by sporc sprout method.

  13. Fundamental study of CO2-H2O-mineral interactions for carbon sequestration, with emphasis on the nature of the supercritical fluid-mineral interface.

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R.; Dewers, Thomas A.; Heath, Jason E.; Wang, Yifeng; Matteo, Edward N.; Meserole, Stephen P.; Tallant, David Robert

    2013-09-01

    In the supercritical CO2-water-mineral systems relevant to subsurface CO2 sequestration, interfacial processes at the supercritical fluid-mineral interface will strongly affect core- and reservoir-scale hydrologic properties. Experimental and theoretical studies have shown that water films will form on mineral surfaces in supercritical CO2, but will be thinner than those that form in vadose zone environments at any given matric potential. The theoretical model presented here allows assessment of water saturation as a function of matric potential, a critical step for evaluating relative permeabilities the CO2 sequestration environment. The experimental water adsorption studies, using Quartz Crystal Microbalance and Fourier Transform Infrared Spectroscopy methods, confirm the major conclusions of the adsorption/condensation model. Additional data provided by the FTIR study is that CO2 intercalation into clays, if it occurs, does not involve carbonate or bicarbonate formation, or significant restriction of CO2 mobility. We have shown that the water film that forms in supercritical CO2 is reactive with common rock-forming minerals, including albite, orthoclase, labradorite, and muscovite. The experimental data indicate that reactivity is a function of water film thickness; at an activity of water of 0.9, the greatest extent of reaction in scCO2 occurred in areas (step edges, surface pits) where capillary condensation thickened the water films. This suggests that dissolution/precipitation reactions may occur preferentially in small pores and pore throats, where it may have a disproportionately large effect on rock hydrologic properties. Finally, a theoretical model is presented here that describes the formation and movement of CO2 ganglia in porous media, allowing assessment of the effect of pore size and structural heterogeneity on capillary trapping efficiency. The model results also suggest possible engineering approaches for optimizing trapping capacity and for monitoring ganglion formation in the subsurface.

  14. Monte Carlo analysis of Pu-H2O and UO2-PuO2-H2O critical assemblies with ENDF/B-IV data

    International Nuclear Information System (INIS)

    A set of critical experiments, comprising thirteen homogeneous Pu-H2O assemblies and twelve UO2-PuO2 lattices, was analyzed with ENDF/B-IV data and the RCPO1 Monte Carlo program, which modeled the experiments explicitly. Some major data sensitivities were also evaluated. For the Pu-H2O assemblies, calculated K/sub eff/ averaged 1.011. The large (2.7%) scatter of K/sub eff/ values for these assemblies was attributed mostly to uncertainties in physical specifications since no clear trends of K/sub eff/ were evident and data sensitivities were insignificant. The UO2-PuO2 lattices showed just one trend of K/sub eff/, which indicated an overprediction of U238 capture consistent with that observed for uranium-H2O experiments. There was however a approx. 1% discrepancy in calculated K/sub eff/ between the two sets of UO2-PuO2 lattices studied

  15. Solid-Liquid Equilibrium in the System of CaCl2-H2O with Special Regard to the Transition Points

    Czech Academy of Sciences Publication Activity Database

    Pátek, Jaroslav; Klomfar, Jaroslav; Součková, Monika

    2008-01-01

    Roč. 53, č. 10 (2008), s. 2260-2271. ISSN 0021-9568 Institutional research plan: CEZ:AV0Z20760514 Keywords : calcium chloride * binary mixture * equilibrium Subject RIV: BJ - Thermodynamics Impact factor: 2.063, year: 2008

  16. Isotopic evidence for the infiltration of mantle and metamorphic CO2-H2O fluids from below in faulted rocks from the San Andreas Fault System

    Energy Technology Data Exchange (ETDEWEB)

    Pili, E.; Kennedy, B.M.; Conrad, M.E.; Gratier, J.-P.

    2010-12-15

    To characterize the origin of the fluids involved in the San Andreas Fault (SAF) system, we carried out an isotope study of exhumed faulted rocks from deformation zones, vein fillings and their hosts and the fluid inclusions associated with these materials. Samples were collected from segments along the SAF system selected to provide a depth profile from upper to lower crust. In all, 75 samples from various structures and lithologies from 13 localities were analyzed for noble gas, carbon, and oxygen isotope compositions. Fluid inclusions exhibit helium isotope ratios ({sup 3}He/{sup 4}He) of 0.1-2.5 times the ratio in air, indicating that past fluids percolating through the SAF system contained mantle helium contributions of at least 35%, similar to what has been measured in present-day ground waters associated with the fault (Kennedy et al., 1997). Calcite is the predominant vein mineral and is a common accessory mineral in deformation zones. A systematic variation of C- and O-isotope compositions of carbonates from veins, deformation zones and their hosts suggests percolation by external fluids of similar compositions and origin with the amount of fluid infiltration increasing from host rocks to vein to deformation zones. The isotopic trend observed for carbonates in veins and deformation zones follows that shown by carbonates in host limestones, marbles, and other host rocks, increasing with increasing contribution of deep metamorphic crustal volatiles. At each crustal level, the composition of the infiltrating fluids is thus buffered by deeper metamorphic sources. A negative correlation between calcite {delta}{sup 13}C and fluid inclusion {sup 3}He/{sup 4}He is consistent with a mantle origin for a fraction of the infiltrating CO{sub 2}. Noble gas and stable isotope systematics show consistent evidence for the involvement of mantle-derived fluids combined with infiltration of deep metamorphic H{sub 2}O and CO{sub 2} in faulting, supporting the involvement of deep fluids percolating through and perhaps weakening the fault zone. There is no clear evidence for a significant contribution from meteoric water, except for overprinting related to late weathering.

  17. High-temperature atomic layer epitaxy of TiO2 from TICl4 and H2O2-H2O

    International Nuclear Information System (INIS)

    Epitaxial TiO2 films were grown on off-cut α-Al2O3 (0112) (R-plane sapphire) substrates by gas-phase atomic layer deposition at 550-750 degrees C. X-ray diffraction and reflection high-energy electron diffraction measurements showed that the films had a two-domain (101) textured rutile structure. The domains made a straight angle about the normal to the substrate (0112) plane; those quantitatively superior were 3 degrees inclined with respect to the plane, resulting in the overall orientation relationship (0112) [2110]sapphire//(101)[010],[010](3 degrees)rutile. An account of the two-domain growth was given. The epitaxial quality worsened with the increase in the deposition temperature. (author)

  18. Sulphur removal from flue gases. Pt.2. Double-alkali method and utilization of by-product (CaSO4·2H2O)

    International Nuclear Information System (INIS)

    The flue gas desulphurization (FGD) technology presented in this paper is designed for a thermal-electric power station. The FGD system receives an hourly volume of flue gases amounting to 530,000 m3 with an average sulphur dioxide concentration of 1.3 g/m3. The FGD process is based on the wet double-alkali method, which ensures: 1) recirculation of the regenerated sorption effluent in the absorption unit, and 2) calcium sulphate sediment as a waste product. In this paper, there is proposed a system for the utilization of the waste product (utilization unit). The processing procedures performed in the utilization unit yield binding materials, commercial gypsum, and building blocks. The FGD process in a no-waste technology which brings about an over 90% abatement of sulphur dioxide and particulate matter emissions. (author). 7 refs, 2 figs

  19. Experimental and kinetic study of the iodine reactivity in low pressure H2/O2/H2O/HI/Ar premixed flames

    International Nuclear Information System (INIS)

    To assess kinetics aspects of iodine chemistry in an environment of a severe accident in a Pressurized Water Reactor (PWR), at the laboratory scale, an experimental reactor named 'flat flame burner' has been implemented. Low pressure flames of H2/O2/Ar premixed gas seeded with known amounts of iodhydric acid and steam were studied. The quantification of chemical species (HI, H2O, OH) in such environment was obtained by specific analytical techniques (Fourier Transform Infrared absorption spectrometry, FTIR and Laser Induced Fluorescence, LIF), the evolution of the temperature was determined by LIF and by thermocouple measurements. Further assays were performed in a flow reactor in which gaseous molecular iodine was injected and transported in a stream or hydrogen flow and a strong temperature gradient, representative of the primary circuit in the case of a severe accident. The resulting gaseous species (I2 and HI) were quantified by ICP-MS and UV-Visible spectrometry. This experimental database has been used as a support to develop a detailed kinetic mechanism for the {I, O, H} system. It is composed of 37 reversible reactions involving 5 iodinated species. The thermo-kinetic parameter database has been actualized by using theoretical chemistry tools and also completed with data found in the literature. Modelling was performed by using the PREMIX code for flame assays, and with the in IRSN's severe accident simulation code ASTEC/SOPHAREOS code for flow reactor assays. The comparison between experiment and modelling shows that this detailed mechanism is able to reproduce the iodine chemistry in conditions representative of a PWR severe accident. (author)

  20. Simulation of Canopy CO2/H2O Fluxes for a Rubber (Hevea Brasiliensis) Plantation in Central Cambodia: The Effect of the Regular Spacing of Planted Trees

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Tomo' omi; Mudd, Ryan; Miyazawa, Yoshiyuki; Liu, Wen; Giambelluca, Thomas; Kobayashi, N.; Lim, Tiva Khan; Jomura, Mayuko; Matsumoto, Kazuho; Huang, Maoyi; Chen, Qi; Ziegler, Alan; Yin, Song

    2013-09-10

    We developed a soil-vegetation-atmosphere transfer (SVAT) model applicable to simulating CO2 and H2O fluxes from the canopies of rubber plantations, which are characterized by distinct canopy clumping produced by regular spacing of plantation trees. Rubber (Hevea brasiliensis Müll. Arg.) plantations, which are rapidly expanding into both climatically optimal and sub-optimal environments throughout mainland Southeast Asia, potentially change the partitioning of water, energy, and carbon at multiple scales, compared with traditional land covers it is replacing. Describing the biosphere-atmosphere exchange in rubber plantations via SVAT modeling is therefore essential to understanding the impacts on environmental processes. The regular spacing of plantation trees creates a peculiar canopy structure that is not well represented in most SVAT models, which generally assumes a non-uniform spacing of vegetation. Herein we develop a SVAT model applicable to rubber plantation and an evaluation method for its canopy structure, and examine how the peculiar canopy structure of rubber plantations affects canopy CO2 and H2O exchanges. Model results are compared with measurements collected at a field site in central Cambodia. Our findings suggest that it is crucial to account for intensive canopy clumping in order to reproduce observed rubber plantation fluxes. These results suggest a potentially optimal spacing of rubber trees to produce high productivity and water use efficiency.

  1. Reduction of pertechnetate by acetohydroxamic acid: Formation of [TcNO(AHA)2(H2O)]+ and implications for the UREX process.

    Energy Technology Data Exchange (ETDEWEB)

    1Harry Reid Center for Environmental Studies, Nuclear Science and Technology Division, University of Nevada, Las Vegas, Las Vegas, NV, 89154-4006; Gong, Cynthia-May S; Poineau, Frederic; Lukens, Wayne W; Czerwinski, Kenneth R.

    2008-02-26

    Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the x-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry with the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a the d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but may be augmented by products of reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex (1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent; titration studies indicate a single species from pH 4.5 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The formation of 1 may strongly impact the fate of technetium in the nuclear fuel cycle.

  2. 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.)

  3. Minister unveils new nanotech centres

    Science.gov (United States)

    Dumé, Belle

    2009-06-01

    Three new nanotechnology research centres are to be set up in France as part of a €70m government plan to help French companies in the sector. Researchers at the new centres, which will be located in Grenoble, Saclay (near Paris) and Toulouse, will be encouraged to collaborate with industry to develop new nanotech-based products. Dubbed NANO-INNOV, the new plan includes €46m for two new buildings at Saclay, with the rest being used to buy new equipment at the three centres and to fund grant proposals from staff to the French National Research Agency (ANR).

  4. 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.

  5. 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.

  6. 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...

  7. Quantum dots in graphene

    OpenAIRE

    Silvestrov, P.G.; Efetov, K. B.

    2006-01-01

    We suggest a way of confining quasiparticles by an external potential in a small region of a graphene strip. Transversal electron motion plays a crucial role in this confinement. Properties of thus obtained graphene quantum dots are investigated theoretically for different types of the boundary conditions at the edges of the strip. The (quasi)bound states exist in all systems considered. At the same time, the dependence of the conductance on the gate voltage carries an information about the s...

  8. 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.

  9. Quantum dot solar cell

    International Nuclear Information System (INIS)

    Full text: The much awaited desire of replacing fossil fuel with photovoltaic will remain a fairy tale if the myriad of issues facing solar cell development are marginalized. Foremost in the list is the issue of cost. Silicon has reached a stage where its use on large scale can no longer be lavishly depended upon. The demand for high grade silicon from the microelectronics and solar industries has soared leading to scarcity. New approach has to be sought. Notable is the increased attention on thin films such as cadmium telluride, copper indium gallium diselenide, amorphous silicon, and the not so thin non-crystalline family of silicon. While efforts to address the issues of stability, toxicity and efficiency of these systems are ongoing, another novel approach is quietly making its appearance - quantum dots. Quantum dots seem to be promising candidates for solar cells because of the opportunity to manipulate their energy levels allowing absorption of a wider solar spectrum. Utilization of minute quantity of these nano structures is enough to bring the cost of solar cell down and to ascertain sustainable supply of useful material. The paper outlines the progress that has been made on quantum dot solar cells. (author)

  10. Radiation sterilization centres worldwide

    International Nuclear Information System (INIS)

    Commercial radiation sterilization has been used for more than 50 years. The Ethicon Division of Johnson and Johnson inaugurated medical device sterilization in 1954 for use with sutures. Over the decades, there has been enormous growth in the disposable medical products market. With this, there has been significant growth in the use of ionizing radiation as a method for sterilization. At present, 40-50% of all disposable medical products manufactured in North America are radiation sterilized. There are now some 160 commercial 60Co irradiators for radiation sterilization operating in 47 countries worldwide, containing approximately 240-260 MCi (8.9-9.6 x 1018 Bq) of gamma emitting 60Co. Included in this are service type facilities operated in research and development centres. Because of the ability to downscale 60Co units, there are many R and D and pilot scale small facilities as well, almost equal in number (approximately 150). When other uses are taken into account, there are in total over 200 gamma irradiators being operated for a variety of purposes in 55 different countries: 100-120 gamma irradiators are located in Europe and in the United States of America. Syringes, surgical gloves, gowns, masks, sticking plasters, dressings, medical 'tetrapacks', bottle teats for premature babies, artificial joints, food packaging, raw materials for pharmaceuticals and cosmetics, and even wine corks, are gamma sterilized. An increasing number of e-beam accelerators are also being operated, but at present e-beam is used for only a minority of radiation sterilized product. The use of e-beam as a radiation source has many attractive features, such as near instantaneous dose delivery, scalability for different throughput, and the capability to integrate in an on-line process. E-beam processing is, however, limited by the penetration of electrons, which is proportional to the accelerator voltage. The highest electron energy used in commercial applications, 10 MeV, penetrates

  11. CERI: Ionizing Radiation Calibration Centre

    International Nuclear Information System (INIS)

    The CERI has been granted by the National Bureau of Metrology (BNM) as an Ionizing Radiation Calibration Centre and as an Estimation and Qualification Centre for the ionizing radiation measurement devices. This article gives some information on the scope covered by the BNM's grant and on the various equipment on which the laboratory relies. It describes the calibration and estimation activities and mentions many kinds of services which are offered to the users mainly in the medical and industrial fields

  12. The centre of the action

    CERN Multimedia

    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.

  13. 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

  14. 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.)

  15. RTEMS Centre - Support and Maintenance Centre to RTEMS Operating System

    Science.gov (United States)

    Silva, H.; Constantino, A.; Freitas, D.; Coutinho, M.; Faustino, S.; Mota, M.; Colaço, P.; Sousa, J.; Dias, L.; Damjanovic, B.; Zulianello, M.; Rufino, J.

    2009-05-01

    RTEMS CENTRE - Support and Maintenance Centre to RTEMS Operating System is a joint ESA/Portuguese Task Force initiative to develop a support and maintenance centre to the Real-Time Executive for Multiprocessor Systems (RTEMS). This paper gives a high level visibility of the progress, the results obtained and the future work in the RTEMS CENTRE [6] and in the RTEMS Improvement [7] projects. RTEMS CENTRE started officially in November 2006, with the RTEMS 4.6.99.2 version. A full analysis of RTEMS operating system was produced. The architecture was analysed in terms of conceptual, organizational and operational concepts. The original objectives [1] of the centre were primarily to create and maintain technical expertise and competences in this RTOS, to develop a website to provide the European Space Community an entry point for obtaining support (http://rtemscentre.edisoft.pt), to design, develop, maintain and integrate some RTEMS support tools (Timeline Tool, Configuration and Management Tools), to maintain flight libraries and Board Support Packages, to develop a strong relationship with the World RTEMS Community and finally to produce some considerations in ARINC-653, DO-178B and ECSS E-40 standards. RTEMS Improvement is the continuation of the RTEMS CENTRE. Currently the RTEMS, version 4.8.0, is being facilitated for a future qualification. In this work, the validation material is being produced following the Galileo Software Standards Development Assurance Level B [5]. RTEMS is being completely tested, errors analysed, dead and deactivated code removed and tests produced to achieve 100% statement and decision coverage of source code [2]. The SW to exploit the LEON Memory Management Unit (MMU) hardware will be also added. A brief description of the expected implementations will be given.

  16. 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.

  17. From single dots to interacting arrays

    OpenAIRE

    Gudmundsson, Vidar; Manolescu, Andrei; Krahne, Roman; Heitmann, Detlef

    2001-01-01

    We explore the structural changes in charge the density and the electron configuration of quantum dots caused by the presence of other dots in an array, and the interaction of neighboring dots. We discuss what recent measurements and calculation of the far-infrared absorption reveal about almost isolated quantum dots and investigate some aspects of the complex transition from isolated dots to dots with strongly overlapping electron density. We also address the the effects on the magnetization...

  18. GRUNCLE, 1. Collision Source Calculation for Program DOT. DOT-3.5, 2-D Neutron Transport, Gamma Transport Program DOT with New Space-Scaling

    International Nuclear Information System (INIS)

    mesh. Anisotropic scattering is treated using a Legendre expansion of arbitrary order. Convergence can be accelerated by several optional schemes, including a pointwise rescaling technique. DOT-3.5/E: Differs from DOT-3.5 in that exponential supplementary equations, as well as the usual diamond and weighted schemes, may be used to find the mesh-centre flux from the fluxes at the faces of the mesh. The model: 1. always gives positive solutions and does not require any fix-up techniques provided that the source is non-negative; 2. improves convergence rate in most neutron deep-penetration problems and, for any practical spatial discretization, always requires CPU times not only smaller than those required by DOT-3 mixed (linear + step fix-up) model, but also shorter (generally 10-20%) than the times required by DOT-3.5 weighted difference model; 3. increasing spatial mesh size supplies solutions which are always reasonable overestimates of the exact solution and its numerical behaviour is more stable and coherent than the mixed mode. Experience up to now from several deep penetration problems in (r,z) and (x,y) geometry shows that, while for neutrons the exponential model almost always works very well, for gamma rays its behaviour may be critical and in some cases there is lack of convergence. C - Restrictions on the complexity of the problem: The total storage requirement is determined by a formula given in the input description. No other restrictions to problem size are applicable

  19. 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.

  20. Nuclear Information Centre is building branch reference centre

    International Nuclear Information System (INIS)

    Reference services are being prepared by the Nuclear Information Centre (NIC) in order to improve information services for nuclear science and technology. The objective is to analyse the user's request, to determine suitable information sources and to provide the end user with a reference to the appropriate information centre, specialized organization or a specialist, or to directly provide the requested information using own information sources. The reference services will use a number of the Centre's own information data files, the data bank of relevant information sources, a personal and corporate file, the record of Czechoslovak nonconventional materials, the data bank of NIC publishing operations, the auxiliary NIC services record, a catalogue of books and journals, and the data bases at NIC. Most information files will be automated and stored on IBM-compatible personal computers. (J.B.). 1 fig., 3 refs

  1. 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)

  2. Electrochromic nanocrystal quantum dots.

    Science.gov (United States)

    Wang, C; Shim, M; Guyot-Sionnest, P

    2001-03-23

    Incorporating nanocrystals into future electronic or optoelectronic devices will require a means of controlling charge-injection processes and an understanding of how the injected charges affect the properties of nanocrystals. We show that the optical properties of colloidal semiconductor nanocrystal quantum dots can be tuned by an electrochemical potential. The injection of electrons into the quantum-confined states of the nanocrystal leads to an electrochromic response, including a strong, size-tunable, midinfrared absorption corresponding to an intraband transition, a bleach of the visible interband exciton transitions, and a quench of the narrow band-edge photoluminescence. PMID:11264530

  3. 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.

  4. The Belgian nuclear research centre

    International Nuclear Information System (INIS)

    The Belgian Nuclear Research Centre is almost exclusively devoted to nuclear R and D and services and is able to generate 50% of its resources (out of 75 million Euro) by contract work and services. The main areas of research include nuclear reactor safety, radioactive waste management, radiation protection and safeguards. The high flux reactor BR2 is extensively used to test fuel and structural materials. PWR-plant BR3 is devoted to the scientific analysis of decommissioning problems. The Centre has a strong programme on the applications of radioisotopes and radiation in medicine and industry. The centre has plans to develop an accelerator driven spallation neutron source for various applications. It has initiated programmes to disseminate correct information on issues of nuclear energy production and non-energy nuclear applications to different target groups. It has strong linkages with the IAEA, OECD-NEA and the Euratom. (author)

  5. 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.

  6. Printer model for dot-on-dot halftone screens

    Science.gov (United States)

    Balasubramanian, Raja

    1995-04-01

    A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L*a*b* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.

  7. Training centres in Latin America

    International Nuclear Information System (INIS)

    Early 1958 the Brazilian representative on the Board of Governors of the International Atomic Energy Agency - supported by the Governors from Argentina and Guatemala -proposed that a study should be made of the possibility of setting up one or more atomic energy training centres in Latin America. On the Board's recommendation, the Director General of the Agency appointed a fact-finding team to make anon-the-spot study. In drafting this report the team was invited to consider the following points: (a) The need for establishing one or more regional training centres; (b) Existing facilities that are being or could be used for training, together with technical data concerning them; (c) The general scientific technological and industrial conditions of the countries visited insofar as they have a bearing on their training needs and capabilities. The authors of the report conclude that 'a training centre in radio-botany should provide vitally needed knowledge and vitally needed specialists to all the agricultural installations in Latin America. A training centre like this might provide an excellent model upon which to base training centres in other areas'. The report recommends that: 1. The Agency should meet the requests of Latin American universities by, for example, supplying equipment and sending experts; 2. At least one specialized training centre should be established as soon as possible. Taking as an example the field of radio-botany, such a centre would provide trained specialists in radio-botany to agricultural institutions throughout Latin America and also provide basic research results vital to agriculture. The cost of new facilities might be of the order of $7 500 000, with an annual budget of approximately $650 000. Staff required: 40 scientists and 175 employees; 3. Whenever it appears feasible to gather necessary staff of high creative ability and established productivity and when funds can be made available for facilities, equipment and operating costs, at

  8. Quantum dot cascade laser

    Science.gov (United States)

    2014-01-01

    We demonstrated an unambiguous quantum dot cascade laser based on InGaAs/GaAs/InAs/InAlAs heterostructure by making use of self-assembled quantum dots in the Stranski-Krastanow growth mode and two-step strain compensation active region design. The prototype generates stimulated emission at λ ~ 6.15 μm and a broad electroluminescence band with full width at half maximum over 3 μm. The characteristic temperature for the threshold current density within the temperature range of 82 to 162 K is up to 400 K. Moreover, our materials show the strong perpendicular mid-infrared response at about 1,900 cm-1. These results are very promising for extending the present laser concept to terahertz quantum cascade laser, which would lead to room temperature operation. PACS 42.55.Px; 78.55.Cr; 78.67.Hc PMID:24666965

  9. 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

  10. 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

  11. The DEMETER Science Mission Centre

    Czech Academy of Sciences Publication Activity Database

    Lagoutte, D.; Brochot, J.; Y.; de Carvalho, D.; Elie, F.; Harivelo, F.; Hobara, Y.; Madrias, L.; Parrot, M.; Pincon, J. L.; Berthelier, J. J.; Peschard, D.; Seran, E.; Gangloff, M.; Sauvaud, J. A.; Lebreton, J. P.; Štverák, Štěpán; Trávníček, Pavel M.; Grygorczuk, J.; Slominski, J.; Wronowski, R.; Barbier, S.; Bernard, P.; Gaboriaud, A.; Wallut, J. M.

    2006-01-01

    Roč. 54, č. 5 (2006), s. 428-440. ISSN 0032-0633 Institutional research plan: CEZ:AV0Z30420517 Keywords : Mission Centre * Data processing Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.509, year: 2006

  12. Vinohrady Sokol centre in Prague

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Markéta

    Prague: Prostor - architektura, interiér, design, 2012 - (Švácha, R.), s. 178-181 ISBN 978-80-87064-09-2 Institutional support: RVO:68378033 Keywords : Sokol centre * functionalism * František Marek * Václav Vejrych * Zbyšek Jirsák Subject RIV: AL - Art, Architecture, Cultural Heritage

  13. ANALYTICAL REVIEW FOR DIFFERENT ASPECTS OF DOT GAIN

    OpenAIRE

    Parag Dnyandeo Nathe

    2013-01-01

    This document gives information about Dot reproduction, Dot gain, factors affecting dot gain, calculation of dot gain measurement and control over dot gain in different controlling parameters. Dot generation in print reproduction and different aspects which causes dot gain during image generation with photochemical process, during printing with mechanical process and during visual inspection of print dot gain is occurred. This document gives information about all causes of dot gain and contr...

  14. The CCCB is a cultural centre, not a tourist centre

    Directory of Open Access Journals (Sweden)

    Elena Xirau

    2004-04-01

    Full Text Available Last February, Barcelona's Centre of Contemporary Culture (CCCB celebrated its first ten years in existence. During this time, this institution has looked to be a showcase to the most modern and innovative cultural expressions focused on reflecting on the concept of the city. In this interview, Josep Ramoneda offers his personal view, as the CCCB's director. He talks of how this cultural project was born, of how the concept of the institution took shape in the CCCB, of its relations with Barcelona's Strategic Plan, of how the project has evolved, of the architectural remodelling of the Casa de la Caritat building for its conversion into a cultural centre, of the relations with other institutions and its future.

  15. The CCCB is a cultural centre, not a tourist centre

    OpenAIRE

    Elena Xirau

    2004-01-01

    Last February, Barcelona's Centre of Contemporary Culture (CCCB) celebrated its first ten years in existence. During this time, this institution has looked to be a showcase to the most modern and innovative cultural expressions focused on reflecting on the concept of the city. In this interview, Josep Ramoneda offers his personal view, as the CCCB's director. He talks of how this cultural project was born, of how the concept of the institution took shape in the CCCB, of its relations with Bar...

  16. Semiconductor nanocrystals inside spherical microcavities: A case of quantum dots in photonic dots

    OpenAIRE

    Artemyev, M. V.

    2003-01-01

    Quantum dots in photonic dots, a new type of microstructures involving highly luminescent II-VI semiconductor nanocrystals has been proposed and realized by incorporating nanocrystals (quantum dots) into glass and polymeric microspheres. The high quality micron-size microspheres represent simplest fully three-dimensional microcavities (photonic dots). Coupling of discrete electron states of quantum dots and photon states inside photonic dots strongly affects onto both stationary and dynamic p...

  17. 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.

  18. DOT Official County Highway Map

    Data.gov (United States)

    Minnesota Department of Natural Resources — The County Highway Map theme is a scanned and rectified version of the original MnDOT County Highway Map Series. The cultural features on some of these maps may be...

  19. 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

  20. 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...

  1. 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...

  2. [CUⅡ(BTAH)2(NCS)2]·2H2O(BTAH=苯并三唑)的合成、晶体结构及其光学性能%Synthesis, Crystal Structure and Optical Properties of Copper Coordination Polymer of Benzotriazole and Thiocyanate, [CuⅡ(BTAH)2(NCS)2]·2H2O (BTAH = Benzotriazole)

    Institute of Scientific and Technical Information of China (English)

    李秀艳; 郭洪猷; 傅吉全

    2006-01-01

    通过水热法,合成了[CuⅡ(BTAH)2(NCS)2]·2H2O晶体.对其进行了元素分析、红外光谱以及热重分析,并通过单晶X射线衍射确定了其晶体结构.该晶体属于三斜晶系,空间群为Pi,晶胞参数为a=0.64174(6)nm,b=0.83749(8)nm,c=0.92831(5)nm,a=71.982(5)°,β=72.522(6)°,γ=77.068(4)°.通过UV-VIS-NIR反射光谱研究了其光学性质,能隙值为2.5eV,吸光系数(ε)为0.0294μm-1.

  3. 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...

  4. 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

  5. Scalable Quantum Computing with "Enhancement" Quantum Dots

    CERN Document Server

    Lyanda-Geller, Y B; Yang, M J

    2005-01-01

    We propose a novel scheme of solid state realization of a quantum computer based on single spin "enhancement mode" quantum dots as building blocks. In the enhancement quantum dots, just one electron can be brought into initially empty dot, in contrast to depletion mode dots based on expelling of electrons from multi-electron dots by gates. The quantum computer architectures based on depletion dots are confronted by several challenges making scalability difficult. These challenges can be successfully met by the approach based on ehnancement mode, capable of producing square array of dots with versatile functionalities. These functionalities allow transportation of qubits, including teleportation, and error correction based on straightforward one- and two-qubit operations. We describe physical properties and demonstrate experimental characteristics of enhancement quantum dots and single-electron transistors based on InAs/GaSb composite quantum wells. We discuss the materials aspects of quantum dot quantum compu...

  6. 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)

  7. 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.

  8. Communicating astronomy by the Unizul Science Centre

    Science.gov (United States)

    Beesham, A.; Beesham, N.

    2015-03-01

    The University of Zululand, situated along the east coast of KwaZulu-Natal, has a thriving Science Centre (USC) situated in the developing port city of Richards Bay. Over 30 000 learners visit the centre annually, and it consists of an exhibition area, an auditorium, lecture areas and offices. The shows consist of interactive games, science shows, competitions, quizzes and matriculation workshops. Outreach activities take place through a mobile science centre for schools and communities that cannot visit the centre.

  9. Teaching and Learning Centres: Towards Maturation

    Science.gov (United States)

    Challis, Di; Holt, Dale; Palmer, Stuart

    2009-01-01

    Approximately 70% of Australian Teaching and Learning Centres have been restructured and/or have undergone leadership changes in the last three years. The volatility of this environment reflects the number of significant challenges faced by Teaching and Learning Centres. In determining what makes Centres successful, the issues that are likely to…

  10. Fossil Dot Com

    DEFF Research Database (Denmark)

    2011-01-01

    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...... 2040. Embodiment of the corporate strategy into designs including urban design, bio refineries, offshore wind, sun and electric vehicles will serve as a platform for describing design challenges of the future - A future where society at large becomes the most important stakeholder demanding sustenance....... Management gurus have taught us for the last 20 years that in the end we all are delivering products and services to end users. This may still hold true; however, we now need to learn that we all are nothing but subsidiary companies of the nature....

  11. 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.

  12. The nonlinear optical rectification coefficient of quantum dots and rings with a repulsive scattering center

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenfang, E-mail: xiewf@gzhu.edu.cn

    2013-11-15

    By using the matrix diagonalization method within the effective-mass approximation, we have investigated the second-order nonlinear optical rectification coefficient associated with intersubband transitions in quantum dots and rings which include a repulsive scattering centre and are subjected to a perpendicular magnetic field. Based on the computed energies and wave functions, we have studied the effects of impurity and magnetic field in quantum dots and rings on this coefficient. The results show that the nonlinear optical properties of quantum dots and rings are strongly affected by the external magnetic field, the quantum size and the impurity. Also we find that the second-order nonlinear optical rectification coefficient of quantum rings shows the Aharonov–Bohm oscillation as the external magnetic field is increased. -- Highlights: • The nonlinear ORC in quantum dots and rings which include a repulsive scattering centre is investigated. • The nonlinear ORC in quantum rings shows the Aharonov–Bohm oscillation as the magnetic field is increased. • The nonlinear ORC shifts to higher energy and increases when the impurity effect is considered.

  13. 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.

  14. Colour centres in barium hexaaluminate (phase I)

    International Nuclear Information System (INIS)

    Colour centres produced by X-ray irradiation of barium hexaaluminate (phase I) with β-alumina structure are studied by electron paramagnetic resonance, optical absorption, and thermally stimulated luminescence. It is shown that in addition to the F+ centres characteristic of β-alumina phases, this compound presents other colour centres such as F, O-, and possibly V-type centres. The stability of these defects is investigated by means of thermal bleaching experiments and thermally stimulated luminescence. An alternative model to the generally accepted one is proposed, for the F+ centres, together with a mechanism of defect formation. (author)

  15. Sensing data centres for energy efficiency.

    Science.gov (United States)

    Liu, Jie; Terzis, Andreas

    2012-01-13

    Data centres are large energy consumers today, and their consumption is expected to increase further, driven by the growth in cloud services. The large monetary cost and the environmental impact of this consumption have motivated operators to optimize data centre management. We argue that one of the underlying reasons for the low-energy utilization is the lack of visibility into a data centre's highly dynamic operating conditions. Wireless sensor networks promise to remove this veil of uncertainty by delivering large volumes of data collected at high spatial and temporal fidelities. The paper summarizes data centre operations in order to describe the parameters that a data centre sensing network should collect and motivate the challenges that such a network faces. We present technical approaches for the problems of data collection and management and close with an overview of a data centre genome, an end-to-end data centre sensing system. PMID:22124086

  16. Discussion on 'Centres of excellence' in Africa

    International Nuclear Information System (INIS)

    In Africa, Centres of Excellence should be oriented to build up scientific and technological capacity in the four topics of international Monitoring System related technologies, namely, seismic monitoring, hydro acoustic monitoring, infrasound monitoring and radionuclides monitoring. Training programs on these topics should be a major objective. A network of such centres should be established in a number of African countries. Centres should be equipped with means and materials for on-line course dispatch to interested training centres or research institutions. African centres should develop strong relationship among themselves through information and data exchange and sharing, harmonization of training programs. National data centres may be established as a component of the African Centre of Excellence. States Signatories may authorize the establishment of a specific fund to support the activities of the African center

  17. 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...

  18. 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 ...

  19. 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...

  20. 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

  1. Quantum dot field effect transistors

    Directory of Open Access Journals (Sweden)

    Frederik Hetsch

    2013-09-01

    Full Text Available Solution processed colloidal semiconductor quantum dots offer a high potential for decreasing costs and expanding versatility of many electronic and optoelectronic devices. Initially used as a research tool to study charge carrier mobilities in closely packed quantum dot thin films, field effect transistors with quantum dots as the active layer have recently experienced a breakthrough in performance (achievement of mobilities higher than 30 cm2 V−1 s−1 as a result of a proper choice of surface ligands and/or improved chemical treatment of the nanoparticle films during device processing. Here we review these innovative developments and the continuing work that may soon lead to commercial grade electronic components.

  2. 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.

  3. 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....

  4. Chaos and Interactions in Quantum Dots

    OpenAIRE

    Alhassid, Y.

    2001-01-01

    Quantum dots are small conducting devices containing up to several thousand electrons. We focus here on closed dots whose single-electron dynamics are mostly chaotic. The mesoscopic fluctuations of the conduction properties of such dots reveal the effects of one-body chaos, quantum coherence and electron-electron interactions.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    . Duty cycle control reduces the circulating current due to the wide input voltage range. With particular transformer windings connection strategy, the proposed boost-type dual input bidirectional converter can draw power from two different dc sources with lower voltage and deliver it to the higher......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 of...... the characteristics of these two power sources: long warm-up stage and low dynamics for fuel cell, and variable terminal voltage for supercapacitors. The motivation for this project was to find ways which can overcome those limitations to integrate fuel cells and supercapcitors to the system with high...

  10. Development and Functions of Retail Centres in Zadar

    OpenAIRE

    Martina Jakovčić; Ivica Rendulić

    2008-01-01

    The paper deals with the development of retail centres in Zadar. Types of retail centres are classified on the basis of the type of business outlets and functions. Four main types of retail centres are: shopping centres, hypermarkets, specialized hypermarkets and shopping centres – hypermarkets. Typology based on the location of centres is also developed. Functions of retail centres are analyzed based on the results gathered by a survey conducted in two retail centres, namely City Galleria – ...

  11. 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.

  12. 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.

  13. 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

  14. Quantum dot photonic crystal lasers

    OpenAIRE

    Yoshie, T.; Shchekin, O. B.; Chen, H.; Deppe, D. G.; Scherer, A.

    2002-01-01

    Coupled cavity designs on two-dimensional square lattice photonic crystal slabs were used to demonstrate optically pumped indium arsenide quantum dot photonic crystal lasers at room temperature. Threshold pump powers of 120 and 370 μW were observed for coupled cavities including two and four defect cavities defined in optimised photonic crystals.

  15. 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

  16. 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.

  17. 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.

  18. 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 develo...... development and environmental sustainability, and further, that technology may not even be the most important feature needed to make them function as such....

  19. 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...

  20. Introducing the Centre for Applied Archaeology

    OpenAIRE

    Dominic Perring

    2008-01-01

    The Centre for Applied Archaeology (CAA) is a new research centre within the Institute of Archaeology, established in 2006 to develop the work of the Institute’s Field Archaeology Unit, Archaeology South-East (ASE), through the creation of a productive research environment and the building of links with academic staff members of the Institute. In this article the Director of CAA defines “applied archaeology” and describes the aims and work of the Centre.

  1. 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....

  2. Bangalore looks to new interdisciplinary science centre

    Science.gov (United States)

    Ramachandran, Ramaseshan

    2008-09-01

    A new centre to boost interdisciplinary research in India is being established in Bangalore - India's IT and software capital. The International Centre for Theoretical Sciences (ICTS) will be led by Spenta Wadia, a theoretical physicist from the Tata Institute of Fundamental Research (TIFR) in Mumbai, which is setting up the new centre. He expects construction of the ICTS, the first of its kind in India, to start by November 2009.

  3. ENERGY EFFICIENT REFURBISHMENT IN AUSTRALIAN SHOPPING CENTRES

    OpenAIRE

    Reed, R. G.; S.J. Wilkinson

    2006-01-01

    Retail shopping centres are a dynamic business in Australia, annually generating $51 billion in sales, employing nearly half a million employees and having an asset value of AUD$69 billion. There are 1,338 retail shopping centres in Australia ranging from large regional centres of more than 100,000 square metres of retail space down to smaller, supermarket based centres of around 5,000 square metres. Importantly they account for 28% of the retail space and generate 41% of retail sales (PCA, 2...

  4. 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.

  5. 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.

  6. 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...

  7. Safety strategy at the RACSO nuclear centre

    International Nuclear Information System (INIS)

    The paper describes in general terms the physical security situation at the RACSO nuclear centre and the principal measures adopted to deal with the risk of subversive activities. Since 1980, Peru had to face terrorist problems; therefore, measures were adopted at RACSO to deal with this risk. As a result, it has been possible to keep the nuclear centre free from terrorist attacks. (author)

  8. Modern Equipment at VATESI Emergency Response Centre

    International Nuclear Information System (INIS)

    The Emergency Response Centre of the State Nuclear Power Safety Inspectorate equipped with state-of-the-art instruments started operating. The Centre is fulfilling the functions prescribed by the Lithuanian legislation in case of an accident at the Ignalina NPP, as well as nuclear or radiation accidents in the neighboring countries in accordance with the Convention on Early Notification

  9. Communications strategy for the Chernobyl Centre

    International Nuclear Information System (INIS)

    This Communications Strategy was developed for the International Chernobyl Centre (ICC) as part of a joint UK/Ukraine project, sponsored by the Department of Trade and Industry and NNC Limited. The Plan was developed during four weeks of workshop discussions in the UK between staff from the centre and experienced PR Professionals from NNC Limited. The requirements for a sustained communications activity at the ICC go much further than simply enhancing or promoting the Centre's scientific and technical activities. Raising sufficient awareness of the Centre among potential funding agents and commercial partners is critical to its future development as a major centre for international co-operation and research. It is only through establishing and developing effective communications that the Centre will become well enough known and understood both within the Ukraine, and internationally, to secure its long term future. However, as the workshop programme unfolded, it also became clear that communications was in itself a legitimate and necessary function of the Centre, and part of the foundations of its existence. The Centre has a fundamental role as an 'information exchange', collecting and communicating information from within the Ukraine to the rest of the world, and interpreting world interest and attitudes to the Ukraine Government and nuclear industry. As such compliments the efforts of individual power plant and corporate PR functions within the Ukraine nuclear energy sector

  10. Next steps towards a Climate Innovation Centre in Ghana. Discussion Paper

    International Nuclear Information System (INIS)

    A climate innovation centre is an institution aimed at enabling development through catalysing climate technology research, development, market creation and policy. This discussion paper discusses the possibilities, considerations and next steps for a Climate Innovation Centre (CIC) in Ghana based on new insights within the government of Ghana, a mapping of climate innovation in Ghana, new developments in the international climate negotiations and other multilateral processes, and analysis conducted by ECN. The conclusion is that a Climate Innovation Centre can fill significant gaps in climate resilient development in Ghana. It seems important that a Ghana CIC does not become yet another institution that focuses on basic research in the area of climate change. Rather, it should connect the dots of the Ghanaian climate innovation system and act as a knowledge facilitator, also for the private sector. Various models of climate innovation centres exist. Before choices are made for a model or a combination of models for Ghana, it is recommended to allow for a broad stakeholder process. The World Bank's infoDev programme could be a model for such a process. Such stakeholder engagement should be aligned with other policymaking processes on adaptation and low-carbon development, as well as related policy arenas, such as agriculture, transport, waste and energy.

  11. CMS Centres Worldwide a New Collaborative Infrastructure

    CERN Document Server

    Taylor, Lucas

    2009-01-01

    The CMS Experiment at the LHC is establishing a global network of inter-connected "CMS Centres" for controls, operations and monitoring. These support: (1) CMS data quality monitoring, detector calibrations, and analysis; and (2) computing operations for the processing, storage and distribution of CMS data. We describe the infrastructure, computing, software, and communications systems required to create an effective and affordable CMS Centre. We present our highly successful operations experiences with the major CMS Centres at CERN, Fermilab, and DESY during the LHC first beam data-taking and cosmic ray commissioning work. The status of the various centres already operating or under construction in Asia, Europe, Russia, South America, and the USA is also described. We emphasise the collaborative communications aspects. For example, virtual co-location of experts in CMS Centres Worldwide is achieved using high-quality permanently-running "telepresence" video links. Generic Web-based tools have been developed ...

  12. 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.

  13. Dot-in-Well Quantum-Dot Infrared Photodetectors

    Science.gov (United States)

    Gunapala, Sarath; Bandara, Sumith; Ting, David; Hill, cory; Liu, John; Mumolo, Jason; Chang, Yia Chung

    2008-01-01

    Dot-in-well (DWELL) quantum-dot infrared photodetectors (QDIPs) [DWELL-QDIPs] are subjects of research as potentially superior alternatives to prior QDIPs. Heretofore, there has not existed a reliable method for fabricating quantum dots (QDs) having precise, repeatable dimensions. This lack has constituted an obstacle to the development of uniform, high-performance, wavelength-tailorable QDIPs and of focal-plane arrays (FPAs) of such QDIPs. However, techniques for fabricating quantum-well infrared photodetectors (QWIPs) having multiple-quantum- well (MQW) structures are now well established. In the present research on DWELL-QDIPs, the arts of fabrication of QDs and QWIPs are combined with a view toward overcoming the deficiencies of prior QDIPs. The longer-term goal is to develop focal-plane arrays of radiationhard, highly uniform arrays of QDIPs that would exhibit high performance at wavelengths from 8 to 15 m when operated at temperatures between 150 and 200 K. Increasing quantum efficiency is the key to the development of competitive QDIP-based FPAs. Quantum efficiency can be increased by increasing the density of QDs and by enhancing infrared absorption in QD-containing material. QDIPs demonstrated thus far have consisted, variously, of InAs islands on GaAs or InAs islands in InGaAs/GaAs wells. These QDIPs have exhibited low quantum efficiencies because the numbers of QD layers (and, hence, the areal densities of QDs) have been small typically five layers in each QDIP. The number of QD layers in such a device must be thus limited to prevent the aggregation of strain in the InAs/InGaAs/GaAs non-lattice- matched material system. The approach being followed in the DWELL-QDIP research is to embed In- GaAs QDs in GaAs/AlGaAs multi-quantum- well (MQW) structures (see figure). This material system can accommodate a large number of QD layers without excessive lattice-mismatch strain and the associated degradation of photodetection properties. Hence, this material

  14. Adiabatic pumping through quantum dots

    International Nuclear Information System (INIS)

    A finite charge can be pumped through a mesoscopic system in the absence of an applied bias voltage by changing periodically in time some parameters of the system. If these parameters change slowly with respect to all internal time scales of the system, pumping is adiabatic. The scope of this work is to investigate adiabatic pumping through a quantum dot, in particular the influence of Coulomb interaction between electrons in the dot on the pumped charge. On one hand we develop a formalism based on Green's functions, in order to calculate the pumped charge from the weak-tunnel-coupling regime down to the Kondo regime. We extend our calculations to a system with a superconducting contact. On the other hand we use a systematic perturbation expansion for the calculation of the pumped charge, giving us the possibility to analyze processes which contribute to charge pumping and to highlight the important role of interaction-induced level renormalization. (orig.)

  15. Quantum dots: promises and accomplishments

    Directory of Open Access Journals (Sweden)

    Dieter Bimberg

    2011-09-01

    Full Text Available Exploration of the Stranski-Krastanow growth of strained semiconductor heterostructures marked the major breakthrough for easy fabrication of defect-free quantum dots (QDs. For the first time, single QDs are facilitating the development of electrically operated emitters of single polarized or entangled photons on demand: an essential component for quantum communication systems. QDs inserted in quantum wells, stacked in planes upon each other, have led to semiconductor lasers that can operate at wavelengths that were previously impossible, or at least difficult to reach, for a given semiconductor family. These lasers show excellent temperature stability, large radiation resistance, and excellent temporal and spatial stability. In this review we discuss recent progress in the field of quantum dot devices.

  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. IDRANAP - European Centre of Excellence

    International Nuclear Information System (INIS)

    Selected by the European Commission (EC) experts out of 185 proposals from 11 countries, IDRANAP (Inter-Disciplinary Research and Applications based on Nuclear and Atomic Physics) is the only EC Centre of Excellence in nuclear physics. The project, initiated and developed by a remarkable team from our institute, researchers with a recognized international scientific level, has as main objectives: - promotion in Romania and in the region of modern applications derived from basic and applied research in nuclear and atomic physics; - disciplinary research in ecology, health, biology, science of materials; - specific nuclear and atomic physics research aimed to open new possibilities for applications; - to ensure stimulative conditions for PhD students from Romania and other EC candidate countries to improve their knowledge and experience by joining scientific activities in the region, a fact that might counteract their tendency to migrate to Western countries. The high scientific level of researchers, their access to national and international facilities as well as the link with prestigious laboratories abroad and the socio-economic demand motivated the development of the project. Among expected results, we mention: improving and spreading the scientific knowledge by publications; producing new facilities, devices and instruments; application of nuclear methods in industry, health-care and environment protection, and training of young researchers. The project consists of 18 workpackages structured in 5 distinct areas: - Determining environmental pollution; - Nuclear methods in biology and medicine; - Radionuclide metrology; - Analysis and characterization of materials; - Nuclei far from stability, decay modes, cosmic rays, and facilities.We make an up-to-date presentation of obtained results and activities performed within IDRANAP project, as well as a short overview of our institute. (author)

  18. 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.

  19. Charging graphene nanoribbon quantum dots

    OpenAIRE

    Żebrowski, D. P.; B. Szafran

    2015-01-01

    We describe charging a quantum dot induced electrostatically within a semiconducting graphene nanoribbon by electrons or holes. The applied model is based on a tight-binding approach with the electron-electron interaction introduced by a mean field local spin density approximation. The numerical approach accounts for the charge of all the $p_z$ electrons and screening of external potentials by states near the charge neutrality point. Both a homogenous ribbon and a graphene flake embedded with...

  20. FRET sensor with quantum dot

    Czech Academy of Sciences Publication Activity Database

    Datinská, Vladimíra; Klepárník, Karel; Belšánová, Barbora; Minárik, M.; Foret, František

    Veszprém: PANNON Egyetem, 2015 - (Mizsey, P.), s. 20-23 ISBN 978-963-396-072-1. [Műszaki Kémiai Napok 2015. Veszprém (HU), 21.04.2015-23.04.2015] R&D Projects: GA ČR(CZ) GA14-28254S; GA TA ČR(CZ) TA02010672 Institutional support: RVO:68081715 Keywords : FRET * quantum dot * sensor Subject RIV: CB - Analytical Chemistry, Separation

  1. FRET sensor with quantum dot

    Czech Academy of Sciences Publication Activity Database

    Datinská, Vladimíra; Klepárník, Karel; Belšánová, Barbora; Minárik, M.; Foret, František

    Veszprém : PANNON Egyetem, 2015 - (Mizsey, P.), s. 20-23 ISBN 978-963-396-072-1. [Műszaki Kémiai Napok 2015. Veszprém (HU), 21.04.2015-23.04.2015] R&D Projects: GA ČR(CZ) GA14-28254S; GA TA ČR(CZ) TA02010672 Institutional support: RVO:68081715 Keywords : FRET * quantum dot * sensor Subject RIV: CB - Analytical Chemistry, Separation

  2. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

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

    2002-01-01

    We have produced GaAs-based quantum-dot edge-emitting lasers operating at 1.16 mu m with record-low transparency current, high output power, and high internal quantum efficiencies. We have also realized GaAs-based quantum-dot lasers emitting at 1.3 mu m, both high-power edge emitters and low-power...... 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...... 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...

  3. Ultrasmall colloidal PbS quantum dots

    International Nuclear Information System (INIS)

    Ultrasmall colloidal lead sulfide quantum dots can increase the open circuit voltages of quantum-dot-based solar cells because of their large energy gap. Their small size and visible or near infrared light-emitting property make them attractive to the applications of biological fluorescence labeling. Through a modified organometallic route, we can synthesize lead sulfide quantum dots as small as 1.6 nm in diameter. The low reaction temperature and the addition of a chloroalkane cosolvent decrease the reaction rate, making it possible to obtain the ultrasmall quantum dots. - Highlights: • Ultrasmall colloidal PbS quantum dots as small as 1.6 nm in diameter are synthesized. • The quantum dots emit red light with photoluminescence peak at 760 nm. • The growth temperature is as low as 50 °C. • Addition of cosolvent 1,2-dichloroethane in the reaction decreases the reaction rate

  4. 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)

  5. 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.

  6. 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...

  7. 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.

  8. Spintronics and Quantum Computing with Quantum Dots

    OpenAIRE

    Recher, P.; Loss, D.; Levy, J

    2000-01-01

    The creation, coherent manipulation, and measurement of spins in nanostructures open up completely new possibilities for electronics and information processing, among them quantum computing and quantum communication. We review our theoretical proposal for using electron spins in quantum dots as quantum bits. We present single- and two qubit gate mechanisms in laterally as well as vertically coupled quantum dots and discuss the possibility to couple spins in quantum dots via superexchange. We ...

  9. 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...

  10. Random Feature Maps for Dot Product Kernels

    CERN Document Server

    Kar, Purushottam

    2012-01-01

    Approximating non-linear kernels using feature maps has gained a lot of interest in recent years due to applications in reducing training and testing times of SVM classifiers and other kernel based learning algorithms. We extend this line of work and present low distortion embeddings for dot product kernels into linear Euclidean spaces. We base our results on a classical result in harmonic analysis characterizing all dot product kernels and use it to define randomized feature maps into explicit low dimensional Euclidean spaces in which the native dot product provides an approximation to the dot product kernel with high confidence.

  11. 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.

  12. Thermoelectric energy harvesting with quantum dots

    International Nuclear Information System (INIS)

    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. (topical review)

  13. 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

  14. 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...

  15. Nuclear Power Plant Temelin Technical Support Centre

    International Nuclear Information System (INIS)

    The erection of the Technical Support Centre for the Nuclear Power Plant Temelin has been a relatively sophisticated and costly issue. It was by proper use of the existing systems, as e.g. I and C, ISE and other systems, that a robust system has been created that is able to meet any requirements laid on the performance of the Technical Support Centre. The decision of the utility CEZ, a.s. that made it possible to establish the Technical Support Centre at the Nuclear Power Plant Temelin has been a right step which shows the level of safety culture within the utility. (author)

  16. 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.

  17. Red luminescence of color centres in sapphire

    International Nuclear Information System (INIS)

    Spectral and polarization studies of the IR photoluminescence of neutron-irradiated sapphire crystals are presented aimed at the clarification of the luminescence centres and the involved electronic transitions. From the temperature dependence of the photoluminescence bands the existence of a potential barrier for the transition from the highest to the lowest excited state of the axial centre was deduced and the height of the barrier was estimated. For a luminescence centre involving a pair of oxygen vacancies with three located electrons a semiquantitative configuration - coordinate diagram is constructed and discussed

  18. 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.

  19. 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

  20. 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...

  1. 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.

  2. The Manche storage centre: Annual report 2010

    International Nuclear Information System (INIS)

    This report presents the installations of the CSM (Centre de Stockage de la Manche), the first French centre for the surface storage of low and intermediate level radioactive wastes. It briefly describes the site and its buildings, the multi-layer principle which is used to cover the wastes, how surface and drainage waters are managed, which controls are performed. It presents the different nuclear safety measures: principles, prevention measures, technical measures to meet the requirements, the legal plan for the control of the Centre and its environment, the quality management organization. It presents the measures regarding radioprotection and safety, indicates incidents and accidents which occurred in 2010, gives information and data on release management (effluents, controls, obtained data on surface and underground waters in different points). It briefly comments how the Centre's wastes are managed, evokes the case of other pollutions, and indicates actions performed in terms of public information

  3. The nuclear research centre at Bariloche, Argentina

    International Nuclear Information System (INIS)

    The nuclear research centre at Bariloche (CAB) is one of the four centres under the Atomic Energy Commission of Argentina (CNEA). The research programme of CAB addresses various issues like nuclear reactor development, nuclear fuel and fuel cycle, applications of radioisotopes and radiation, and waste management. There is also a basic nuclear science component. The human resource development in the areas of physics and nuclear engineering is done in an associated Balseiro Institute which has undergraduate and graduate programmes as well as doctoral and postdoctoral research. The Centre interacts well with the society and provides services in the nuclear area. It has a close interaction with the nuclear sector of Argentina as also with many international organisations. Regulatory control over the Centre is carried out by the Nuclear Regulatory Authority of Argentina. (author)

  4. Deloitte Global Immigration Service Centre -- Business Plan

    OpenAIRE

    Mejtský, Miroslav

    2013-01-01

    The thesis "Deloitte Global Immigration Service Centre -- Business Plan" is in the theoretical part focused on the aspects of the business plan as a document, the ways of its evaluation and financing business in general. The practical part is focused on creation of a business plan for a project of Global Immigration Service Centre with all the essentials in order to verify the feasibility of the project. The project seems feasible for implementation based on the results of the thesis.

  5. Nuclear research centres - The Egyptian experiment

    International Nuclear Information System (INIS)

    The Atomic Energy Authority of Egypt has four research centres located at two sites. Its research reactors are devoted to the production of isotopes, neutron beam experiments, activation analysis and materials research. The accelerators are devoted to the production of short lived isotopes for medical applications and materials R and D. Irradiation technology is used for sterilization of medical supplies and food preservation. High level of expertise in those centres is also useful for other developmental activities in Egypt. (author)

  6. Karlsruhe Nuclear Research Centre. Programme budget 1988

    International Nuclear Information System (INIS)

    Following a general survey of tasks, planned activities and developmental trends of the nuclear research centre, the report gives an account of the activities to be performed in the subject fields of main interest, showing the budgeting figures for annual expenditure (for personnel, investments, operating costs) up to the year 1991. Further information explains the infrastructure of the centre and the distribution of overall expenditure as well as the budgetary planning. (UA)

  7. 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.)

  8. 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 ...

  9. 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

  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. 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...

  12. 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

  13. 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.

  14. The Imperial College Thermophysical Properties Data Centre

    Science.gov (United States)

    Angus, S.; Cole, W. A.; Craven, R.; de Reuck, K. M.; Trengove, R. D.; Wakeham, W. A.

    1986-07-01

    The IUPAC Thermodynamic Tables Project Centre in London has at its disposal considerable expertise on the production and utilization of high-accuracy equations of state which represent the thermodynamic properties of substances. For some years they have been content to propagate this information by the traditional method of book production, but the increasing use of the computer in industry for process design has shown that an additional method was needed. The setting up of the IUPAC Transport Properties Project Centre, also at Imperial College, whose products would also be in demand by industry, afforded the occasion for a new look at the problem. The solution has been to set up the Imperial College Thermophysical Properties Data Centre, which embraces the two IUPAC Project Centres, and for it to establish a link with the existing Physical Properties Data Service of the Institution of Chemical Engineers, thus providing for the dissemination of the available information without involving the Centres in problems such as those of marketing and advertising. This paper outlines the activities of the Centres and discusses the problems in bringing their products to the attention of industry in suitable form.

  15. 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

  16. Optical anisotropy in vertically coupled quantum dots

    DEFF Research Database (Denmark)

    Yu, Ping; Langbein, Wolfgang Werner; Leosson, Kristjan;

    1999-01-01

    We have studied the polarization of surface and edge-emitted photoluminescence (PL) from structures with vertically coupled In0.5Ga0.5As/GaAs quantum dots (QD's) grown by molecular beam epitaxy. The PL polarization is found to be strongly dependent on the number of stacked layers. While single...... number due to increasing dot size....

  17. 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.

  18. 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.

  19. 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.

  20. 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...