Sample records for imidogen nh x-triplet-sigma

  1. Threshold photoelectron spectroscopy of the imidogen radical

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Gustavo A., E-mail: [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Gans, Bérenger [Institut des Sciences Moléculaires d’Orsay, Univ Paris-Sud, CNRS, Bât 210, Univ Paris-Sud, 91405 Orsay Cedex (France); Tang, Xiaofeng [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Ward, Michael; Batut, Sébastien [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Nahon, Laurent [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Fittschen, Christa [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Loison, Jean-Christophe [ISM, Université de Bordeaux, CNRS, 351 cours de la Libération, 33405 Talence Cedex (France)


    We present the threshold photoelectron spectroscopy of the imidogen radical (NH) recorded in the photon energy region up to 1 eV above its first ionization threshold. The radical was produced by reaction of NH{sub 3} and F in a microwave discharge flow-tube and photoionized using vacuum ultraviolet (VUV) synchrotron radiation. A double imaging coincidence spectrometer was used to record mass-selected spectra and avoid contributions from the byproducts present in the reactor and background gas. The energy region includes the ground X{sup +2}Π and first electronically excited a{sup +4}Σ{sup −} states of NH{sup +}. Strong adiabatic transitions and weak vibrational progressions up to v{sup +} = 2 are observed for both electronic states. The rotational profile seen in the origin band has been modeled using existing neutral and cationic spectroscopic constants leading to a precise determination of the adiabatic ionization energy at 13.480 ± 0.002 eV.

  2. Aquaporin 4 as a NH3 Channel

    DEFF Research Database (Denmark)

    Assentoft, Mette; Kaptan, Shreyas; Schneider, Hans-Peter


    that the ionic NH4 (+) did not permeate AQP4. Molecular dynamics simulations revealed partial pore permeation events of NH3 but not of NH4 (+) and a reduced energy barrier for NH3 permeation through AQP4 compared with that of a cholesterol-containing lipid bilayer, suggesting AQP4 as a favored transmembrane...... route for NH3 Our data propose that AQP4 belongs to the growing list of NH3-permeable water channels....

  3. TKS-Vega experiment - NH and NH2 bands in Comet Halley

    Energy Technology Data Exchange (ETDEWEB)

    Krasnopol' skii, V.A.; Tkachuk, A.IU. (AN SSSR, Institut Kosmicheskikh Issledovanii, Moscow (USSR))


    An analysis is conducted of the March 9, 1986 distribution of the NH 336-nm band and the NH2 bands in the 580-700 nm region on Comet Halley. Of all candidates considered, only ammonia suggests itself as a parent of both NH2 and NH. The ammonia production rate is obtained from measurements of NH2 bands by dividing the observed Q(NH2) by 0.92, which is the yield of NH2 in NH3 photolysis. The NH3 presently measured is an order of magnitude lower than that derived from the Giotto IMS data. 28 refs.

  4. Cold and ultracold NH--NH collisions in magnetic fields

    CERN Document Server

    Janssen, Liesbeth M C; van der Avoird, Ad; Groenenboom, Gerrit C; Hutson, Jeremy M


    Elastic and spin-changing inelastic collision cross sections are presented for cold and ultracold magnetically trapped NH. The cross sections are obtained from coupled-channel scattering calculations as a function of energy and magnetic field. We specifically investigate the influence of the intramolecular spin-spin, spin-rotation, and intermolecular magnetic dipole coupling on the collision dynamics. It is shown that $^{15}$NH is a very suitable candidate for evaporative cooling experiments. The dominant trap-loss mechanism in the ultracold regime originates from the intermolecular dipolar coupling term. At higher energies and fields, intramolecular spin-spin coupling becomes increasingly important. Our qualitative results and conclusions are fairly independent of the exact form of the potential and of the size of the channel basis set.

  5. Li-5(BH4)(3)NH

    DEFF Research Database (Denmark)

    Wolczyk, Anna; Paik, Biswajit; Sato, Toyoto


    = 7.0474(2) angstrom at 77 degrees C. The crystal structure of Lis(BH4)(3)NH has been solved in space group Pnma, and refined coupling density functional theory (DFT) and synchrotron radiation X-ray powder diffraction data have been obtained for a 3LiBH(4):2Li(2)NH ball-milled and annealed sample...

  6. Volatility of NH3 from internally mixed sodium succinate-NH4SO4 particles (United States)

    Wang, Na; Zhang, Yunhong


    Contributing the complicacy of atmospheric constituents, aerosol particles may undergo complicated heterogeneous reactions that have profound consequences on their hygroscopic properties and volatility. Ammonia (NH3) is a ubiquitous trace atmospheric gas in the troposphere and has negative effects on human health and climate forcing of ambient aerosols. In addition, atmospheric cycle of NH3 is complex in atmosphere, therefore it necessary to get insights to the complexity of gas-to-aerosol NH3 partitioning, which results in large uncertainties in the sources and distributions of NH3. By using in-situ Fourier transform infrared spectroscopy and attenuated total reflection (FTIR-ATR), we report here the volatility of NH3 from the laboratory generated sodium succinate with ammonium sulfate ((NH4)2SO4) at a 1:1 molar ratio as well as its effect on the hygroscopicity of the mixtures. The loss of the NH4+ peak at 1451cm-1 and the formation of peaks at 1718 and 1134 cm-1 due to C = O stretching asymmetric vibration of -COOH and ν3 (SO42-) stretching of sodium sulfate indicate that sodium succinate reacts with (NH4)2SO4, releasing NH3 and forming succinic acid and sodium sulfate on dehydration process. The formation of less hygroscopic succinic acid and volatility of NH3 in mixtures leads to a significant decrease in the total water content. To the best of our knowledge, this is the first report of the reaction between (NH4)2SO4 and dicarboxylate salts, which may represent an important particle-gas partitioning for ammonia and thus elucidate another underlying ammonia cycle in atmosphere. These results could be helpful to understand the mutual transformation process of dicarboxylic acids and dicarboxylate salts.

  7. Structural determinants of NH3 and NH4+ transport by mouse Rhbg, a renal Rh glycoprotein. (United States)

    Abdulnour-Nakhoul, Solange; Le, Trang; Rabon, Edd; Hamm, L Lee; Nakhoul, Nazih L


    Renal Rhbg is localized to the basolateral membrane of intercalated cells and is involved in NH3/NH4(+) transport. The structure of Rhbg is not yet resolved; however, a high-resolution crystal structure of AmtB, a bacterial homolog of Rh, has been determined. We aligned the sequence of Rhbg to that of AmtB and identified important sites of Rhbg that may affect transport. Our analysis positioned three conserved amino acids, histidine 183 (H183), histidine 342 (H342), and tryptophan 230 (W230), within the hydrophobic pore where they presumably serve to control NH3 transport. A fourth residue, phenylalanine 128 (F128) was positioned at the upper vestibule, presumably contributing to recruitment of NH4(+) We generated three mutations each of H183, H342, W230, and F128 and expressed them in frog oocytes. Immunolabeling showed that W230 and F128 mutants were localized to the cell membrane, whereas H183 and H342 staining was diffuse and mostly intracellular. To determine function, we compared measurements of NH3/NH4(+) and methyl amine (MA)/methyl ammonium (MA(+))-induced currents, intracellular pH, and surface pH (pHs) among oocytes expressing the mutants, Rhbg, or injected with H2O. In H183 and W230 mutants, NH4(+)-induced current and intracellular acidification were inhibited compared with that of Rhbg, and MA-induced intracellular alkalinization was completely absent. Expression of H183A or W230A mutants inhibited NH3/NH4(+)- and MA/MA(+)-induced decrease in pHs to the level observed in H2O-injected oocytes. Mutations of F128 did not significantly affect transport of NH3 or NH4(+) These data demonstrated that mutating H183 or W230 caused loss of function but not F128. H183 and H342 may affect membrane expression of the transporter.

  8. Imaging a multidimensional multichannel potential energy surface: Photodetachment of H-(NH3) and NH4- (United States)

    Hu, Qichi; Song, Hongwei; Johnson, Christopher J.; Li, Jun; Guo, Hua; Continetti, Robert E.


    Probes of the Born-Oppenheimer potential energy surfaces governing polyatomic molecules often rely on spectroscopy for the bound regions or collision experiments in the continuum. A combined spectroscopic and half-collision approach to image nuclear dynamics in a multidimensional and multichannel system is reported here. The Rydberg radical NH4 and the double Rydberg anion NH4- represent a polyatomic system for benchmarking electronic structure and nine-dimensional quantum dynamics calculations. Photodetachment of the H-(NH3) ion-dipole complex and the NH4- DRA probes different regions on the neutral NH4 PES. Photoelectron energy and angular distributions at photon energies of 1.17, 1.60, and 2.33 eV compare well with quantum dynamics. Photoelectron-photofragment coincidence experiments indicate dissociation of the nascent NH4 Rydberg radical occurs to H + NH3 with a peak kinetic energy of 0.13 eV, showing the ground state of NH4 to be unstable, decaying by tunneling-induced dissociation on a time scale beyond the present scope of multidimensional quantum dynamics.

  9. Thermodynamics of Cu(Ⅱ)-NH3-NH4Cl-H2O system

    Institute of Scientific and Technical Information of China (English)

    JU Shao-hua; TANG Mo-tang; YANG Sheng-hai; TANG Chao-bo


    The thermodynamics of a complex solution system, Cu(Ⅱ)-NH3-NH4Cl-H2O, was presented both theoretically and experimentally. Firstly, according to the principles of simultaneous equilibrium and aqueous electronic charge neutrality of the system, a nonlinear mathematical thermodynamic model with multi-members was set up. In this model, there were six unknowns: pH value, concentration values of free Cl-, free NH3, total concentration values of Cu2+, Cl- and NH3, four equilibrium equations and three equilibrium equations of total quantum of Cu2+, Cl- and NH3, as well as an equilibrium equation of electric charge, were involved in the model. Then after specifying the values of total concentrate of NH3 and Cl-, the model was solved precisely using MATLAB language, and the other four unknowns were obtained. According to the values obtained above, various valuable figures regarding thermodynamic relation of the system were protracted also with MATLAB, including two and three dimensions figures. These figures and data can supply the theoretic conference for optimizing the ratio of leaching reagents in copper extraction through ammonia hydrometallurgy. Finally, the solubility of CuO were measured in the system of NH3-NH4Cl-H2O. The results show that the model and the thermodynamic data obtained are reliable.

  10. Hot NH3 Spectra for Astrophysical Applications

    CERN Document Server

    Hargreaves, R J; Bernath, P F


    We present line lists for ammonia (NH$_{3}$) at high temperatures obtained by recording Fourier transform infrared emission spectra. Calibrated line lists are presented for twelve temperatures (300 -- 1300$^{\\circ}$C in 100$^{\\circ}$C intervals and 1370$^{\\circ}$C) and each line list covers the 740 -- 2100 cm$^{-1}$ range, which includes the majority of the $\

  11. NH3 Measurements for Advanced SCR Applications

    NARCIS (Netherlands)

    Seykens, X.; Tillaart, E. van den; Lilova, V.; Nakatani, S.


    Since the introduction of Euro IV legislation [1, 2], Selective Catalytic Reduction (SCR) technology using liquid urea injection is (one of) the primary methods for NOx reduction in many applications. Ammonia (NH3) is the reagent and key element for the SCR system and its control calibration to meet

  12. Cold and ultracold NH--NH collisions: The field-free case

    CERN Document Server

    Janssen, Liesbeth M C; van der Avoird, Ad; Hutson, Jeremy M; Groenenboom, Gerrit C


    We present elastic and inelastic spin-changing cross sections for cold and ultracold NH($X\\,^3\\Sigma^-$) + NH($X\\,^3\\Sigma^-$) collisions, obtained from full quantum scattering calculations on an accurate \\textit{ab initio} quintet potential-energy surface. Although we consider only collisions in zero field, we focus on the cross sections relevant for magnetic trapping experiments. It is shown that evaporative cooling of both fermionic $^{14}$NH and bosonic $^{15}$NH is likely to be successful for hyperfine states that allow for $s$-wave collisions. We also demonstrate that the calculated cross sections are sensitive to the details of the interaction potential, but that the qualitative results are fairly independent of the precise form of the surface. The results are also found to be reasonably independent of the size of the angular basis set. We therefore argue that, within the uncertainty limits of the potential, full basis-set convergence is not strictly necessary.

  13. Crystal structure of [UO2(NH35]NO3·NH3

    Directory of Open Access Journals (Sweden)

    Patrick Woidy


    Full Text Available Pentaammine dioxide uranium(V nitrate ammonia (1/1, [UO2(NH35]NO3·NH3, was obtained in the form of yellow crystals from the reaction of caesium uranyl nitrate, Cs[UO2(NO33], and uranium tetrafluoride, UF4, in dry liquid ammonia. The [UO2]+ cation is coordinated by five ammine ligands. The resulting [UO2(NH35] coordination polyhedron is best described as a pentagonal bipyramid with the O atoms forming the apices. In the crystal, numerous N—H...N and N—H...O hydrogen bonds are present between the cation, anion and solvent molecules, leading to a three-dimensional network.

  14. Hydrogen Abstraction from Hydrocarbons by NH2. (United States)

    Siddique, Kamal; Altarawneh, Mohammednoor; Gore, Jeff; Westmoreland, Phillip R; Dlugogorski, Bogdan Z


    This contribution investigates thermokinetic parameters of bimolecular gas-phase reactions involving the amine (NH2) radical and a large number of saturated and unsaturated hydrocarbons. These reactions play an important role in combustion and pyrolysis of nitrogen-rich fuels, most notably biomass. Computations performed at the CBS-QB3 level and based on the conventional transition-state theory yield potential-energy surfaces and reaction rate constants, accounting for tunnelling effects and the presence of hindered rotors. In an analogy to other H abstraction systems, we demonstrate only a small influence of variational effects on the rate constants for selected reaction. The studied reactions cover the abstraction of hydrogen atoms by the NH2 radical from the C-H bonds in C1-C4 species, and four C5 hydrocarbons of 2-methylbutane, 2-methyl-1-butene, 3-methyl-1-butene, 3-methyl-2-butene, and 3-methyl-1-butyne. For the abstraction of H from methane, in the temperature windows 300-500 and 1600-2000 K, the calculated reaction rate constants concur with the available experimental measurements, i.e., kcalculated/kexperimetal = 0.3-2.5 and 1.1-1.4, and the previous theoretical estimates. Abstraction of H atom from ethane attains the ratio of kcalculated/kexperimetal equal to 0.10-1.2 and 1.3-1.5 over the temperature windows of available experimental measurements, i.e., 300-900 K and 1500-2000 K, respectively. For the remaining alkanes (propane and n-butane), the average kexperimental/kcalculated ratio remains 2.6 and 1.3 over the temperature range of experimental data. Also, comparing the calculated standard enthalpy of reaction (ΔrH°298) with the available experimental measurements for alkanes, we found the mean unsigned error of computations as 3.7 kJ mol(-1). This agreement provides an accuracy benchmark of our methodology, affording the estimation of the unreported kinetic parameters for H abstractions from alkenes and alkynes. On the basis of the Evans

  15. Stereodynamics and Rovibrational Effect for H+NH3 →H2+NH2 Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Hao; LIU Xin-Guo; ZHANG Qing-Gang


    @@ We employ the semirigid vibrating rotor target (SVRT) model to study the influence of rotational and vibrational excitation of the reagent on reactivity for the reaction H+NH3. The excitation of the pseudo H-NH2 stretching vibration of the SVRT model gives significant enhancement of reaction probability. Detailed study of the influence of initial rotational states on reaction probability shows strong steric effect. The steric effect of polyatomic reactions, treated by the SVRT model, is more complex and richer than theoretical calculations involving linear molecular models.

  16. Spectroscopic parameters of the low-lying electronic states and laser cooling feasibility of NH+ cation and NH- anion (United States)

    Zhang, Qing-Qing; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Liu, Wen-Wang


    The potential energy curves and transition dipole moments of 12Σ+, 22Σ+, 12Π and 22Π states of NH+ cation and NH- anion are calculated by using multi-reference configuration interaction method and large all-electron basis sets. Based on the obtained potential energy curves, the rotational and vibrational energy levels of the states are obtained by solving the Schrödinger equation of nuclear movement. The calculated spectroscopic parameters for NH+ cation and NH- anion are in good agreement with available theoretical and experimental results. The spin orbit coupling effect of the 2Π states for both NH+ cation and NH- anion are calculated. The feasibility of laser cooling of the two molecules is examined by using the results of the molecular structure and spectroscopy. The highly diagonal Franck-Condon factors for the 12Π (v″ = 0) ↔ 12Σ+ (v‧ = 0) transition of NH+ and NH- are 0.821 and 0.999, while the radiative lifetimes of the 12Σ+ (v‧ = 0) state for the two molecules are 384 ns and 52.4 ns, respectively. The results indicate that NH+ cation and NH- anion are good candidate molecules for laser cooling. The cooling scheme via Sisyphus process for the NH+ cation and NH- anion are proposed in the paper. The laser wavelengths for the close cycles of the absorption and radiation are also determined. Unfortunately, the potential energy curve of the ground state of the neutral NH molecule shows that the auto-detachment of NH- anion is possible, implying the optical scheme of laser cooling for NH- anion is not easy to achieve in the experiment although it has larger Franck-Condon factor.

  17. Spectroscopic parameters of the low-lying electronic states and laser cooling feasibility of NH(+) cation and NH(-) anion. (United States)

    Zhang, Qing-Qing; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Liu, Wen-Wang


    The potential energy curves and transition dipole moments of 1(2)Σ(+), 2(2)Σ(+), 1(2)Π and 2(2)Π states of NH(+) cation and NH(-) anion are calculated by using multi-reference configuration interaction method and large all-electron basis sets. Based on the obtained potential energy curves, the rotational and vibrational energy levels of the states are obtained by solving the Schrödinger equation of nuclear movement. The calculated spectroscopic parameters for NH(+) cation and NH(-) anion are in good agreement with available theoretical and experimental results. The spin orbit coupling effect of the (2)Π states for both NH(+) cation and NH(-) anion are calculated. The feasibility of laser cooling of the two molecules is examined by using the results of the molecular structure and spectroscopy. The highly diagonal Franck-Condon factors for the 1(2)Π (v″=0)↔1(2)Σ(+) (v'=0) transition of NH(+) and NH(-) are 0.821 and 0.999, while the radiative lifetimes of the 1(2)Σ(+) (v'=0) state for the two molecules are 384ns and 52.4ns, respectively. The results indicate that NH(+) cation and NH(-) anion are good candidate molecules for laser cooling. The cooling scheme via Sisyphus process for the NH(+) cation and NH(-) anion are proposed in the paper. The laser wavelengths for the close cycles of the absorption and radiation are also determined. Unfortunately, the potential energy curve of the ground state of the neutral NH molecule shows that the auto-detachment of NH(-) anion is possible, implying the optical scheme of laser cooling for NH(-) anion is not easy to achieve in the experiment although it has larger Franck-Condon factor. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. NH3 and NH4+ permeability in aquaporin-expressing Xenopus oocytes

    DEFF Research Database (Denmark)

    Holm, Lars M.; Jahn, Thomas Paul; Møller, Anders Laurell Blom;


    We have shown recently, in a yeast expression system, that some aquaporins are permeable to ammonia. In the present study, we expressed the mammalian aquaporins AQP8, AQQP9, AQP3, AQP1 and a plant aquaporin TIP2;1 in Xenopus oocytes to study the transport of ammonia (NH3) and ammonium (NH4+) under...... opencircuit and voltage-clamped conditions. TIP2;1 was tested as the wild-type and in a mutated version (tip2;1) in which the water permeability is intact. When AQP8-, AQP9-, AQP3- and TIP2;1-expressing oocytes were placed in a well-stirred bathing medium of low buffer capacity, NH3 permeability was evident...... from the acidification of the bathing medium; the effects observed with AQP1 and tip2;1 did not exceed that of native oocytes. AQP8, AQP9, AQP3, and TIP2;1 were permeable to larger amides, while AQP1 was not. Under voltage-clamp conditions, given sufficient NH3, AQP8, AQP9, AQP3, and TIP2;1 supported...


    Directory of Open Access Journals (Sweden)



    Full Text Available 2(Cy2NH22SO4Sn(SO42Cy2NH2Cl and 2(Cy2NH22SO4. Sn(SO422Cy2NH2Cl complexes have been obtained on allowing Cy2NH2O2C-SO3H and Cy2NH2HSO4 to react respectively with SnBu2Cl2 and SnBu3Cl in specific ratios.The molecular structures of these compounds have been determined on the basis of the infrared data. The suggested structures are dimeric, the tin atom being octacoordinated by four chelating sulfate anions, the monomeric basic entities being connected by hydrogen bonded cation chloride cation strings.

  20. Effects of reactant rotational excitations on H2 + NH2 → H + NH3 reactivity (United States)

    Song, Hongwei; Guo, Hua


    Rotational mode specificity of the title reaction is examined using an initial state selected time-dependent wave packet method on an accurate ab initio based global potential energy surface. This penta-atomic reaction presents an ideal system to test several dynamical approximations, which might be useful for future quantum dynamics studies of polyatomic reactions, particularly with rotationally excited reactants. The first approximation involves a seven-dimensional (7D) model in which the two non-reactive N-H bonds are fixed at their equilibrium geometry. The second is the centrifugal sudden (CS) approximation within the 7D model. Finally, the J-shifting (JS) model is tested, again with the fixed N-H bonds. The spectator-bond approximation works very well in the energy range studied, while the centrifugal sudden and J-shifting integral cross sections (ICSs) agree satisfactorily with the coupled-channel counterparts in the low collision energy range, but deviate at the high energies. The calculated integral cross sections indicate that the rotational excitation of H2 somewhat inhibits the reaction while the rotational excitations of NH2 have little effect. These findings are compared with the predictions of the sudden vector projection model. Finally, a simple model is proposed to predict rotational mode specificity using K-averaged reaction probabilities.

  1. UF6 and UF4 in liquid ammonia: [UF7(NH3)]3- and [UF4(NH3)4]. (United States)

    Kraus, Florian; Baer, Sebastian A


    From the reaction of uranium hexafluoride UF6 with dry liquid ammonia, the [UF7(NH3)]3- anion and the [UF4(NH3)4] molecule were isolated and identified for the first time. They are found in signal-green crystals of trisammonium monoammine heptafluorouranate(IV) ammonia (1:1; [NH4]3[UF7(NH3)].NH3) and emerald-green crystals of tetraammine tetrafluorouranium(IV) ammonia (1:1; [UF4(NH3)4].NH3). [NH4]3[UF7(NH3)].NH3 features discrete [UF7(NH3)]3- anions with a coordination geometry similar to a bicapped trigonal prism, hitherto unknown for U(IV) compounds. The emerald-green [UF4(NH3)4].NH3 contains discrete tetraammine tetrafluorouranium(IV) [UF4(NH3)4] molecules. [UF4(NH3)4].NH3 is not stable at room temperature and forms pastel-green [UF4(NH3)4] as a powder that is surprisingly stable up to 147 degrees C. The compounds are the first structurally characterized ammonia complexes of uranium fluorides.

  2. Generation of nanopores during desorption of NH3 from Mg(NH3)6Cl2

    DEFF Research Database (Denmark)

    Hummelshøj, Jens Strabo; Sørensen, Rasmus Zink; Kostova, M.Y.;


    It is shown that nanopores are formed during desorption of NH3 from Mg(NH3)6Cl2, which has been proposed as a hydrogen storage material. The system of nanopores facilitates the transport of desorbed ammonia away from the interior of large volumes of compacted storage material. DFT calculations show...... that there exists a continuous path from the initial Mg(NH3)6Cl2 material to MgCl2 that does not involve large-scale material transport. Accordingly, ammonia desorption from this system is facile....

  3. GLOBEC NEP Northern California Current Bird Data NH0005, 0007 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) Northern California Current Bird Data from R/V New Horizon cruises NH0005 and 0007. As a part of...

  4. The weak fundamental NH-stretching transition in amines (United States)

    Schrøder, Sidsel D.; Hansen, Anne S.; Wallberg, Jens H.; Nielsen, Anne R.; Du, Lin; Kjaergaard, Henrik G.


    Absolute intensities of NH-stretching fundamental and overtone transitions of gas phase aniline, methylamine, ethylamine, cyclopropylamine, methylethylamine, diethylamine and pyrrolidine have been measured with long path length conventional absorption spectroscopy. To support the assignments of NH-stretching transitions, transition frequencies and intensities were calculated with the local mode model using ab initio calculated local mode parameters and dipole moment functions obtained at the CCSD(T)-F12a/VDZ-F12 level of theory. For aniline, the absolute intensities of the NH-stretching transitions show the typical decrease of approximately an order of magnitude for each successive vibrational excitation. For methylamine, ethylamine, cyclopropylamine, methylethylamine, diethylamine and pyrrolidine, the observed absolute intensities of the fundamental NH-stretching transition is weak and of similar strength or even weaker than the corresponding first overtone transition. Characteristic for the amines with a normal fundamental intensity is a conjugated double bond next to the amine group.

  5. Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Multisensor Analyzed Sea Ice Extent Northern Hemisphere (MASIE-NH) products provide measurements of daily sea ice extent and sea ice edge boundary for the...

  6. NH and Mg Index Trends in Elliptical Galaxies

    CERN Document Server

    Serven, Jedidiah; Toloba, Elisa; Sánchez-Blázquez, Patricia


    We examine the spectrum in the vicinity of the NH3360 index of Davidge & Clark (1994), which was defined to measure the NH absorption around 3360 ̊A and which shows almost no trend with velocity dispersion (Toloba et al. 2009), unlike other N- sensitive indices, which show a strong trend (Graves et al. 2007). Computing the effect of individual elements on the integrated spectrum with synthetic stellar population integrated spectra, we find that, while being well correlated with nitrogen abundance, NH3360 is almost equally well anti-correlated with Mg abundance. This prompts the definition of two new indices, Mg3334, which is mostly sensitive to magnesium, and NH3375, which is mostly sensitive to nitrogen. Rather surprisingly, we find that the new NH3375 index shows a trend versus optical absorption feature indices that is as shallow as the NH3360 index. We hypothesize that the lack of a strong index trend in these near-UV indices is due to the presence of an old metal-poor component of the galactic pop...

  7. The NH$_2$D hyperfine structure revealed by astrophysical observations

    CERN Document Server

    Daniel, F; Punanova, A; Harju, J; Faure, A; Roueff, E; Sipilä, O; Caselli, P; Güsten, R; Pon, A; Pineda, J E


    The 1$_{11}$-1$_{01}$ lines of ortho and para--NH$_2$D (o/p-NH$_2$D), respectively at 86 and 110 GHz, are commonly observed to provide constraints on the deuterium fractionation in the interstellar medium. In cold regions, the hyperfine structure due to the nitrogen ($^{14}$N) nucleus is resolved. To date, this splitting is the only one which is taken into account in the NH$_2$D column density estimates. We investigate how the inclusion of the hyperfine splitting caused by the deuterium (D) nucleus affects the analysis of the rotational lines of NH$_2$D. We present 30m IRAM observations of the above mentioned lines, as well as APEX o/p-NH$_2$D observations of the 1$_{01}$-0$_{00}$ lines at 333 GHz. The hyperfine spectra are first analyzed with a line list that only includes the hyperfine splitting due to the $^{14}$N nucleus. We find inconsistencies between the line widths of the 1$_{01}$-0$_{00}$ and 1$_{11}$-1$_{01}$ lines, the latter being larger by a factor of $\\sim$1.6$\\pm0.3$. Such a large difference is...

  8. Rotational Spectroscopy of the NH3-H2 Molecular Complex (United States)

    Surin, L. A.; Tarabukin, I. V.; Schlemmer, S.; Breier, A. A.; Giesen, T. F.; McCarthy, M. C.; van der Avoird, A.


    We report the first high resolution spectroscopic study of the NH3–H2 van der Waals molecular complex. Three different experimental techniques, a molecular beam Fourier transform microwave spectrometer, a millimeter-wave intracavity jet OROTRON spectrometer, and a submillimeter-wave jet spectrometer with multipass cell, were used to detect pure rotational transitions of NH3–H2 in the wide frequency range from 39 to 230 GHz. Two nuclear spin species, (o)-NH3–(o)-H2 and (p)-NH3–(o)-H2, have been assigned as carriers of the observed lines on the basis of accompanying rovibrational calculations performed using the ab initio intermolecular potential energy surface (PES) of Maret et al. The experimental spectra were compared with the theoretical bound state results, thus providing a critical test of the quality of the NH3–H2 PES, which is a key issue for reliable computations of the collisional excitation and de-excitation of ammonia in the dense interstellar medium.

  9. Wet Mechanochemical Processing of Celestine using (NH42CO3

    Directory of Open Access Journals (Sweden)

    Deniz Bingöl


    Full Text Available In this study, traditional (univariate method of processing to the wet mechanochemical treatment were applied to obtain both SrCO3 and (NH42SO4 from celestite (SrSO4-(NH42CO3-H2O mixtures in a planetary ball mill. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and chemical analysis were used to analyze products formed during wet milling. A hydrometallurgical process was carried out to examine milling time, ball to grinding material mass ratio, (NH42CO3 to SrSO4 mole ratio and rotational speed of the mill in a planetary mill. Under optimum conditions, a conversion approaching 100% of SrCO3 was obtained.

  10. Formulation of an inhibitor radiopharmaceutical of prostatic antigen of {sup 177}Lu-Glu-Nh-CO-Nh-Lys membrane; Formulacion de un radiofarmaco inhibidor del antigeno prostatico de membrana {sup 177}Lu-Glu-NH-CO-NH-Lys

    Energy Technology Data Exchange (ETDEWEB)

    Ortega S, D.


    The prostate specific membrane antigen (PSMA) is a zinc metalloenzyme that is expressed on the cell membrane and highly expressed in prostate cancer. Recently, it has been demonstrated that the peptide sequence Glu-Nh-CO-Nh-Lys inhibit PSMA activity through an electrostatic interaction with the Zn. Several theragnostic radiopharmaceuticals with base in {sup 177}Lu have been developed for radiotherapy of specific molecular targets because gamma and beta emissions of the radionuclide (β = 0.498 MeV and γ= 0.133 MeV). However, there is currently no label a formulation for preparing a radiopharmaceutical of {sup 177}Lu-Glu-Nh-CO-Nh-Lys useful treatment of prostate cancer. The aim of this research was to optimize and document the process of production of the radiopharmaceutical {sup 177}Lu-Glu-Nh-CO-Nh-Lys for sanitary registration application before the Comision Federal para la Proteccion contra Riesgos Sanitarios (COFEPRIS). The optimization of the production process was assessed a factorial design of three variables with mixed levels (3 x 3 x 2) where the dependent variable is the radiochemical purity, the analytical method was validated by UV-Vis spectrophotometry. Next, process validation was carried out by labeling 3 lots of the optimized formulation of the radiopharmaceutical (5.55 GBq (2.16 μg) of {sup 177}LuCl{sub 3}, 90 mg peptide PSMA, 50 mg ascorbic acid and 150 μL of acetate buffer 1 M ph 5), long-term stability was performed by high resolution liquid chromatography) to determine its useful shelf life. 3 validation batches were prepared under protocols of Good Manufacturing Practice (GMP) in the Production Plant of Radiopharmaceuticals of the Instituto Nacional de Investigaciones Nucleares (ININ), meet specifications preset by obtaining a sterile and free development of bacterial endotoxin yields of labeled 100% and which retains its quality characteristics radiochemical purity greater than 90% for at least 15 days. (Author)

  11. First detection of ammonia (NH3) in the upper troposphere (United States)

    Höpfner, Michael; Volkamer, Rainer; Grabowski, Udo; Grutter de la Mora, Michel; Orphal, Johannes; Stiller, Gabriele; von Clarmann, Thomas


    Ammonia (NH3) is the major alkaline trace gas in the troposphere. Neutralization of atmospheric acids, like HNO3 and H2SO4, leads to formation of ammonium nitrate and ammonium sulfate aerosols. Further, there are indications that NH3 may enhance nucleation of sulfuric acid aerosols by stabilization of sulfuric acid clusters. By far the largest source of ammonia is agricultural food production. Major global emissions are located in S-E Asia as e.g. shown by satellite nadir observations. Besides its importance with respect to air quality issues, an increase of ammonia emissions in the 21st century might lead to a significant climate radiative impact through aerosol formation. In spite of its significance, there is a lack of observational information on the global distribution of NH3 in the mid- and upper troposphere. Observational evidence, however, would be important for testing e.g. model results on the fate of ammonia from its source regions on ground to altitudes up to the tropopause. In this contribution we will show, to our knowledge, the first unequivocal detection of ammonia in the upper troposphere. This result has been achieved through analysis of infrared limb-emission observations performed with the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument on board the Envisat satellite from 2002-2012. On a global scale, enhanced values of ammonia have been measured in the upper tropospheric region influenced by the Asian monsoon. We will present a quantitative analysis of the retrieved concentrations of NH3 including an error assessment and further retrieval diagnostics. The results will be discussed with respect to the variability of NH3 locally within the Asian monsoon region's upper troposphere and at different years. Further, we will show comparisons between global distributions of NH3 from published model simulations and our observational dataset from MIPAS.

  12. Urban NH3 levels and sources in a Mediterranean environment (United States)

    Reche, Cristina; Viana, Mar; Pandolfi, Marco; Alastuey, Andrés; Moreno, Teresa; Amato, Fulvio; Ripoll, Anna; Querol, Xavier


    Urban NH3 concentrations were mapped in Barcelona (Spain) by means of passive samplers (dosimeters). Average NH3 levels were 9.5 μg m-3 in summer and 4.4 μg m-3 in winter, higher than those reported in other urban background sites in Europe, this being especially notable in summer. During this season, values were significantly higher at urban background than at traffic sites, probably indicating the impact of emissions from biological sources, such as humans, sewage systems and garbage containers. Thus, the volatilization of NH3 from the aerosol phase seems to be significant enough during summer to dominate over traffic emissions. Conversely, in winter levels were higher at traffic sites, suggesting a contribution from vehicle emissions. Indeed, NH3 levels decreased by 55% with increasing distance (50 m) to the direct emissions from traffic. A significant correlation between NH3 concentrations averaged for the different districts of the city and the number of waste containers per hm2 was also obtained, highlighting the necessity for controlling and reducing the emissions from garbage collection systems. The urban topography of the Barcelona historical city centre, characterised by narrow streets with a high population density, seemed to exert a strong influence on NH3 levels, with levels reaching up to 30 μg m-3 as a consequence of limited dispersion and ventilation conditions. The impact of the sewage system emissions was also detected with an increase of levels when measuring immediately above the source, even though further studies are required to evaluate the relevance of these emissions.

  13. Latest nH analysis in the Double Chooz experiment

    CERN Document Server

    Yang, Guang


    Precise measurement of the neutrino mixing angle $\\theta_{13}$ is the primary goal of the Double Chooz Experiment (DC), which is located in Chooz, France. The inverse beta decay process provides a unique signature of reactor anti-neutrino interactions, giving prompt signals from positron annihilation and delayed signals from neutron capture by either Gadolinium (Gd) or Hydrogen (H). This paper is dedicated to the latest nH analysis in Double Chooz. Typically, The Gd analysis is primary since fewer background events are involved. However, with accurate estimates of backgrounds and a precise reconstruction of energy, the nH analysis gives a powerful independent measurement of $\\theta_{13}$.

  14. New syntheses and structural characterization of NH3BH2Cl and (BH2NH2)3 and thermal decomposition behavior of NH3BH2Cl. (United States)

    Lingam, Hima K; Wang, Cong; Gallucci, Judith C; Chen, Xuenian; Shore, Sheldon G


    New convenient procedures for the preparation of ammonia monochloroborane (NH(3)BH(2)Cl) and cyclotriborazane [(BH(2)NH(2))(3)] are described. Crystal structures have been determined by single-crystal X-ray diffraction. Strong H···Cl···H bifurcated hydrogen bonding and weak N-H···H dihydrogen bonding are observed in the crystal structure of ammonia monochloroborane. When heated at 50 °C or under vacuum, ammonia monochloroborane decomposes to (NH(2)BHCl)(x), which was characterized by NMR, elemental analysis, and powder X-ray diffraction. Redetermination of the crystal structure of cyclotriborazane at low temperature by single-crystal X-ray diffraction analysis provides accurate hydrogen positions. Similar to ammonia borane, cyclotriborazane shows extensive dihydrogen bonding of N-H···H and B-H···H bonds with H(δ+)···H(δ-) interactions in the range of 2.00-2.34 Å.

  15. NH[sub 3] semi-hermetic compressor from ILKA Mafa. NH[sub 3]-Halbhermetikverdichter von ILKA Mafa

    Energy Technology Data Exchange (ETDEWEB)



    Towards the end of the lecture programme at the 1998 DKV Congress there was a well-visited and interesting lecture by Dipl.-Ing. Siegfried Laute on the revolutionary development by ILKA Mafa Kltemaschinenbau GmbH from Halle of the NH[sub 3] semi-hermetic compressor and on the results obtained with it in the course of its five years' use in practice (see DKV Report KK 2/99, p. 19). This development is of the greatest importance for the further spread of NH[sub 3] as a substitute for R22 as well as for applications which have always worked with NH[sub 3].

  16. New series of potent delta-opioid antagonists containing the H-Dmt-Tic-NH-hexyl-NH-R motif. (United States)

    Li, Tingyou; Shiotani, Kimitaka; Miyazaki, Anna; Fujita, Yoshio; Tsuda, Yuko; Ambo, Akihiro; Sasaki, Yusuke; Jinsmaa, Yunden; Marczak, Ewa; Bryant, Sharon D; Lazarus, Lawrence H; Okada, Yoshio


    Heterodimeric compounds H-Dmt-Tic-NH-hexyl-NH-R (R=Dmt, Tic, and Phe) exhibited high affinity to delta- (K(i)delta=0.13-0.89nM) and mu-opioid receptors (K(i)mu=0.38-2.81nM) with extraordinary potent delta antagonism (pA(2)=10.2-10.4). These compounds represent the prototype for a new class of structural homologues lacking mu-opioid receptor-associated agonism (IC(50)=1.6-5.8muM) based on the framework of bis-[H-Dmt-NH]-alkyl (Okada, Y.; Tsuda, Y.; Fujita, Y.; Yokoi, T.; Sasaki, Y.; Ambo, A.; Konishi, R.; Nagata, M.; Salvadori, S.; Jinsmaa, Y.; Bryant, S. D.; Lazarus, L. H. J. Med. Chem.2003, 46, 3201), which exhibited both high mu affinity and bioactivity.


    NARCIS (Netherlands)


    The kinetics of NH4+ and NO3- uptake in young Douglas fir trees (Pseudotsuga menziesii [Mirb.] Franco) were studied in solutions, containing either one or both N species. Using solutions containing a single N species, the V(max) of NH4+ uptake was higher than that of NO3- uptake. The K(m) of NH4+

  18. α-NH4Fe(HAsO42

    Directory of Open Access Journals (Sweden)

    Najoua Ouerfelli


    Full Text Available The title compound α-ammonium iron(III bis[hydrogen arsenate(V], α-NH4Fe(HAsO42 (or poly[ammonium bis(μ-hydrogen arsenatoferrate(III], {NH4[Fe(HAsO42]}n, synthesized hydrothermally, is isostructural with NH4Fe(HPO42. Condensation of the hydrogen arsenate groups with FeO6 coordination octahedra via common corners results in an overall three-dimensional framework containing interconnected channels parallel to the a-, b- and c-axis directions. The NH4+ cations are located in three intersecting tunnels, which is promising as an ion exchange. Hydrogen bonding of the types O—H...O and N—H...O consolidates the packing of the structure. The distortion of the coordination polyhedra is analyzed by means of the effective coordination number and distortion indices. Structural relationships with other compounds of general formula MIMIII[HXO4]2 (X = P, As are discussed.

  19. 77 FR 74725 - New Hampshire Disaster #NH-00024 (United States)


    ... ADMINISTRATION New Hampshire Disaster NH-00024 AGENCY: U.S. Small Business Administration. ACTION: Notice... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement Center... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  20. 78 FR 48764 - New Hampshire Disaster # NH-00026 (United States)


    ... ADMINISTRATION New Hampshire Disaster NH-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice.../02/2014. ADDRESSES: Submit completed loan applications to: U.S. Small Business Administration... CONTACT: A. Escobar, Office of Disaster Assistance, U.S. Small Business Administration, 409 3rd Street...

  1. 76 FR 77578 - New Hampshire Disaster #NH-00022 (United States)


    ... ADMINISTRATION New Hampshire Disaster NH-00022 AGENCY: U.S. Small Business Administration. ACTION: Notice...: Submit completed loan applications to: U.S. Small Business Administration, Processing and Disbursement... of Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite...

  2. [Mechanism of NH(4+)-N removal in drinking water biofilter]. (United States)

    Liu, Bing; Fan, Hui; Yu, Guo-Zhong; Yu, Xin; Zhao, Cheng-Mei; Li, Qing-Fei; Zhang, Shu-Ting; Wei, Bo


    In order to explore the mechanism of NH(4+)-N removal in drinking water biofilter, water quality parameters, such as NH(4+)-N, NO(2-)-N, NO(3-)-N, total phosphorus, permanganate index, nitrogen gas, temperature and dissolved oxygen etc, were determined in the inflow and outflow of biofilter. Samples of granular activated carbon (GAC) at different height (0, 10, 20, 40, 60 cm) of the biofiter media were collected and analyzed for the bacterial community with molecular biology techniques. The bacterial diversity in the activated carbon biofilm sample was studied based on the phylogenetic analysis of sequences. The results showed that there were three stages according to the NH(4+)-N concentration in the influent. The "nitrogen loss" phenomenon (total inorganic nitrogen in the effluent was less than that in the influent) occurred at the first, second and third stages and the amount of nitrogen loss were 0.94, 0.32 and 0.15 mg x L(-1), respectively. The amount of nitrogen loss had a good positive correlation with the NH(4+)-N concentration in the influent, but not a linear relationship with the concentration of the permanganate index in the influent. The average concentrations of N2 increased gradually with the height of media in the biofilter, with values of 14.04 and 14.67 mg x L(-1) in the influent and the effluent, respectively. Based on the sequencing results, the ammonia-oxidizing bacteria (AOB) in the activated carbon biofilm were classified into three common genera: Nitrosococcus, Nitrosomonas and Nitrosospira. When the NH(4+)-N concentration in the influent was relatively high, the "nitrogen loss" phenomenon in biofilter was caused by the AOB.

  3. A Simple Synthetic Methodology for NH4PF6%制备 NH4PF6简易方法研究

    Institute of Scientific and Technical Information of China (English)

    李洪亮; 郭国霖


      In this paper, a new simple methodology for preparing NH4PF6 was studied. It has been found that a trace of water can catalyze the reaction between NH4F and PCl5, and the reaction can react without extra heater. The products were separated applying the different solubility of NH4Cl and NH4PF6 in acetone and water. The X-ray diffraction spectra and the FT-IR spectra demonstrated that the NH4PF6 was prepared in this condition, and the separation method is effective. Two mechanism of the water-catalyzed reaction were proposed and explained in detail.

  4. (NH4)2SO4 heterogeneous nucleation and glycerol evaporation of (NH4)2SO4-glycerol system in its dynamic efflorescence process (United States)

    Cai, Chen; Luan, Ye-mei; Shi, Xiao-min; Zhang, Yun-hong


    Using the FTIR-ATR technique, we investigated the heterogeneous nucleation process of aqueous (NH4)2SO4 binary droplets and (NH4)2SO4/glycerol ternary droplets. From the red shift of δ-NH4+ with a linearly declining relative humidity (RH), the ERHs of pure (NH4)2SO4 droplets and mixed (NH4)2SO4/glycerol droplets with different organic-inorganic ratio (OIR) of 1:4, 1:2 and 1:1 ranges from ∼51.9 to ∼34.9%, ∼49.8 to ∼33.0%, ∼48.0 to ∼30.6% and ∼43.7 to ∼25.2%, respectively. From the changing absorbance of δ-NH4+ band, we determined the heterogeneous nucleation rates of crystalline (NH4)2SO4 in the pure and mixed droplets. The interfacial tension between an (NH4)2SO4 critical nucleus and surrounding (NH4)2SO4 solution was determined using classical nucleation theory and experimental data to be 0.031 ± 0.002 J m-2. Evaporation of glycerol in (NH4)2SO4/glycerol ternary droplets are also studied to be restrained by participation of (NH4)2SO4. Determined vapour pressure of glycerol is on the same magnitude with results from previous studies.

  5. Leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system

    Institute of Scientific and Technical Information of China (English)

    WANG Rui-xiang; TANG Mo-tang; YANG Sheng-hai; ZHAGN Wen-hai; TANG Chao-bo; HE Jing; YANG Jian-guang


    The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size,reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined.The leaching kinetics of low-grade zinc oxide ore in NH3-NH4Cl-H2O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69μm, holding at 80℃ for 60min, sum ammonia concentration of 7.5mol/L, the molar ratio of ammonium to ammonia being 2:1, and the ratio (g/mL) of solid to liquid being 1:10.

  6. Thermodynamic Analysis and Comparison on Low Temperature CO2-NH3 Cascade Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    查世彤; 马一太; 申江; 李敏霞


    This paper is focused on the cascade refrigeration cycle using natural refrigerant CO2-NH3. The properties of refrigerants CO2 and NH3 are introduced and analyzed.CO2 has the advantage in low stage of cascade refrigeration cycle due to its good characteristics and properties. The thermodynamic analysis results of the CO2-NH3 cascade refrigeration cycle demonstrates that the cycle has an optimum condensation temperature of low stage and also has an optimum flow rate ratio.By comparing with the R13-R22 and NH3-NH3 cascade refrigeration cycles, the mass flow rate ratio of CO2-NH3 is larger than those of R13-R22 and NH3-NH3, the theoretical COP of CO2-NH3 cascade refrigeration cycle is larger than that of the R13-R22 cascade cycle and smaller than that of the NH3-NH3 cascade cycle. But the real COP of CO2-NH3 cascade cycle will be higher than those of R13-R22 and NH3-NH3 because the specific volume of CO2 at low temperature does not change much and its dynamic viscosity is also small.

  7. The C(3P) + NH3 reaction in interstellar chemistry: II. Low temperature rate constants and modeling of NH, NH2 and NH3 abundances in dense interstellar clouds

    CERN Document Server

    Hickson, Kevin M; Bourgalais, Jérémy; Capron, Michael; Picard, Sebastien D Le; Goulay, Fabien; Wakelam, Valentine


    A continuous supersonic flow reactor has been used to measure rate constants for the C + NH3 reaction over the temperature range 50 to 296 K. C atoms were created by the pulsed laser photolysis of CBr4. The kinetics of the title reaction were followed directly by vacuum ultra-violet laser induced fluorescence (VUV LIF) of C loss and through H formation. The experiments show unambiguously that the reaction is rapid at 296 K, becoming faster at lower temperatures, reaching a value of 1.8 10-10 cm3 molecule-1 s-1 at 50 K. As this reaction is not currently included in astrochemical networks, its influence on interstellar nitrogen hydride abundances is tested through a dense cloud model including gas-grain interactions. In particular, the effect of the ortho-to-para ratio of H2 which plays a crucial role in interstellar NH3 synthesis is examined.

  8. NH4+ rather than NO3- production and retention processes are susceptible to enhanced NH4+ deposition in a subtropical plantation (United States)

    Gao, Wenlong; Kou, Liang; Yang, Hao; Zhang, Jinbo; Muller, Christoph; Li, Shenggong


    It remains largely unknown how increasing N depositions may alter soil N cycling and N retention capacity of subtropical/tropical forest ecosystem functions. Here we report results from a 15N tracing study on soil from a subtropical forest plantation in China. Nitrogen fertilizer was applied monthly for more than 2.5 years at a rate of 40 (low) and 120 (high) kg NH4Cl-N hm-2 yr-1, respectively. High NH4+ input significantly retarded gross N mineralization, with a greater inhibition on mineralization of recalcitrant organic N than labile organic N which can possibly be related to a decreased fungal biomass. With increasing NH4+ inputs, rates of NH4+ immobilization into recalcitrant organic-N showed a trend of rise first and then fall. Interestingly, microbial NH4+ cycling moved toward to be a more open N cycling under low NH4+ input conditions, but was driven to be a tightly coupled N cycling under high NH4+ input conditions. On the contrary, microbial NO3- production (heterotrophic nitrification and autotrophic nitrification) and retention (NO3- immobilization and DNRA) processes showed insensitivity to elevated NH4+ input. Our results highlight that in acid subtropical/tropical forest soil, NH4+ rather than NO3- production and retention processes are susceptible to enhanced NH4+ deposition.

  9. NH{sub 4}-doped anodic WO{sub 3} prepared through anodization and subsequent NH{sub 4}OH treatment for water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Wook; Kim, Sunkyu; Seong, Mijeong; Yoo, Hyeonseok; Choi, Jinsub, E-mail:


    Highlights: • NN{sub 4}-doped WO{sub 3} was successfully fabricated by a wet-based method using ammonium hydroxide (NH{sub 4}OH). • (NH{sub 4}){sub 10}W{sub 12}O{sub 41} phase was formed during the NH{sub 4}OH treatment. • Over-doped NH{sub 4} in WO{sub 3} led to reduced photo-electrochemical performance for OER. • The optimized surface was achieved by thermal treatment of anodic WO{sub 3} with 2 g of NH{sub 4}OH solution. - Abstract: Tungsten trioxide (WO{sub 3}) prepared by anodization of a W foil was doped with NH{sub 4} through NH{sub 4}OH treatment at 450 °C. Since aqueous NH{sub 4}OH was used during doping instead of NH{sub 3} gas, the treatment step does not require complicated annealing facilities. Moreover, the state of doped N is a form of NH{sub 3}-W instead of W{sub 2}N, which lowers the bandgap but increases photocorrosion. We found that incorporation of NH{sub 4} into WO{sub 3} leads to reduction of the bandgap from 2.9 eV to 2.2 eV, regardless of the amount of NH{sub 4}OH treatment, lowering the onset potential and increasing the current density at fixed potential for oxygen evolution reaction under illumination. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the surface morphologies, crystallinities of tungsten oxides and existence of NH{sub 4} doping, respectively. The bandgap energy was determined by UV–Vis spectroscopy to measure the transmittance and refraction. The water splitting performance of each sample was measured by electrochemical linear sweep voltammetry in a 3-electrode configuration under illumination.

  10. Study of vibrational spectra of NH sub 4 Cl and NH sub 4 Br at high pressure

    CERN Document Server

    Glazkov, V P; Syrykh, G F; Kozlenko, D P; Savenko, B N; Telepnev, A S


    The NH sub 4 Cl vibrational spectra at the pressures up to 2.6 GPa and the NH sub 4 Br spectra at the pressures up to 7 GPa are studied through the method of the neutrons inelastic incoherent scattering. It is established that the linear baric dependence of the libration mode changes its inclination in the area above the pressure of transition from the disordered cubic phase to the ordered cubic phase with the CsCl-type structure. The baric dependence inclination of the cross-sectional optical translation mode remains unchanged. The evaluations of the Grueneisen parameters are presented in the one-dimensional approximation and the form of the potential function for the libration oscillations in the disordered and ordered cubic phases with the CsCl-type structure is calculated. It is shown that the observed effects are related to the high anharmonism of the potential in the disordered phase

  11. Evaluation of antioxidant properties of a phosphorated cardanol compound on mineral oils (NH10 and NH20)

    Energy Technology Data Exchange (ETDEWEB)

    Maria Alexsandra Rios Facanha; Selma Elaine Mazzetto; Jose Osvaldo Beserra Carioca; Glaucione Gomes de Barros [Universidade Federal do Ceara (Brazil). Departamento de Quimica Organica e Inorganica


    Studies on thermal-oxidative stability of a phosphorated antioxidant, synthesized from a natural and renewable resource cashew nut shell liquid (CNSL) was investigated, using a classical thermoanalytical method-thermogravimetric (TG/DTG) in air atmosphere. Its use as an antioxidant agent on the mineral oils NH10 and NH{sub 2}0 was evaluated in comparative studied with a commercial product (diphenyl phosphate - Aldrich). The addition of 1.2-2.0 wt% of phosphorated cardanol compound to the mineral oils has improved their thermal-oxidative stability on 14-18{sup o}C, respectively. The occurrence of major thermal degradation events at higher temperatures (T{sub max}) on additivated oils is an excellent indication of the phosphorated cardanol compound antioxidant properties. 21 refs., 9 figs., 6 tabs.

  12. Complete Series of Alkali-Metal M(BH3NH2BH2NH2BH3) Hydrogen-Storage Salts Accessed via Metathesis in Organic Solvents. (United States)

    Owarzany, Rafał; Fijalkowski, Karol J; Jaroń, Tomasz; Leszczyński, Piotr J; Dobrzycki, Łukasz; Cyrański, Michał K; Grochala, Wojciech


    We report a new efficient way of synthesizing high-purity hydrogen-rich M(BH3NH2BH2NH2BH3) salts (M = Li, Na, K, Rb, Cs). The solvent-mediated metathetic synthesis applied here uses precursors containing bulky organic cations and weakly coordinating anions. The applicability of this method permits the entire series of alkali-metal M(BH3NH2BH2NH2BH3) salts (M = Li, Na, K, Rb, Cs) to be obtained, thus enabling their comparative analysis in terms of crystal structures and hydrogen-storage properties. A novel polymorphic form of Verkade's base (C18H39N4PH)(BH3NH2BH2NH2BH3) precursor was also characterized structurally. For all compounds, we present a comprehensive structural, spectroscopic, and thermogravimetric characterization (PXRD, NMR, FTIR, Raman, and TGA/DSC/MS).

  13. Thermodynamics and technology of extracting gold from low-grade gold ore in system of NH4Cl-NH3-H2O

    Institute of Scientific and Technical Information of China (English)


    According to the principles of simultaneous chemical equilibrium and electronic charge neutrality, the thermodynamics of Au-NH4Cl-NH3-H2O system was studied by using the exponential computation method and through MATLAB programming, and the solid figure of potential-c(NH4Cl)-c(NH4OH) was drawn. The results show that when the sum concentration of Au+ and Au3+ is equal to5 × 10-5 mol/L, ψ(Au+/Au) is about -0.2 V; when the sum comes up to 0.5 mol/L, the value of ψ(Au+/Au) increases to 0.2 V. In this case, ψ(O2/OH-) is as high as 0.7 V. This means that it is feasible to extract gold in this system. In addition, to predict the feasibility of reducing gold from the Au(Ⅰ)-NH4Cl-NH3-H2O system with copper or zinc powder, the solid figures of potential-c(NH4Cl)-c(NH4OH)for both systems of Cu-NH4Cl-NH3-H2O and Zn-NH4Cl-NH3-H2O were also drawn. The results indicate that both copper and zinc powders can reduce Au+ into metal gold, and zinc powder can also reduce H2O into H2, while copper powder can not. The leaching results of a cuprous gold ore show that the extraction of gold can reach 80% in this system. The preliminary results of reduction with copper and zinc powders show that with deoxygenizing, the reduction effects are relatively good.

  14. Parallel Changes in Intracellular Water Volume and pH Induced by NH3/NH4+ Exposure in Single Neuroblastoma Cells

    Directory of Open Access Journals (Sweden)

    Víctor M. Blanco


    Full Text Available Background: Increased blood levels of ammonia (NH3 and ammonium (NH4+, i.e. hyperammonemia, leads to cellular brain edema in humans with acute liver failure. The pathophysiology of this edema is poorly understood. This is partly due to incomplete understanding of the osmotic effects of the pair NH3/NH4+ at the cellular and molecular levels. Cell exposure to solutions containing NH3/NH4+ elicits changes in intracellular pH (pHi, which can in turn affect cell water volume (CWV by activating transport mechanisms that produce net gain or loss of solutes and water. The occurrence of CWV changes caused by NH3/NH4+ has long been suspected, but the mechanisms, magnitude and kinetics of these changes remain unknown. Methods: Using fluorescence imaging microscopy we measured, in real time, parallel changes in pHi and CWV caused by brief exposure to NH3/NH4+ of single cells (N1E-115 neuroblastoma or NG-108 neuroblastoma X glioma loaded with the fluorescent indicator BCECF. Changes in CWV were measured by exciting BCECF at its intracellular isosbestic wavelength (∼438 nm, and pHi was measured ratiometrically. Results: Brief exposure to isosmotic solutions (i.e. having the same osmolality as that of control solutions containing NH4Cl (0.5- 30 mM resulted in a rapid, dose-dependent swelling, followed by isosmotic regulatory volume decrease (iRVD. NH4Cl solutions in which either extracellular [NH3] or [NH4+] was kept constant while the other was changed by varying the pH of the solution, demonstrated that [NH3]o rather than [NH4+]o is the main determinant of the NH4Cl-induced swelling. The iRVD response was sensitive to the anion channel blocker NPPB, and partly dependent on external Ca2+. Upon removal of NH4Cl, cells shrank and displayed isosmotic regulatory volume increase (iRVI. Regulatory volume responses could not be activated by comparable CWV changes produced by anisosmotic solutions, suggesting that membrane stretch or contraction by themselves are

  15. C-NH2 bond formation mediated by iridium complexes


    Mena, Inmaculada; Casado, Miguel A.; Polo, Víctor; García-Orduña, P.; Lahoz, Fernando J.; Oro, Luis A.


    In the presence of phosphanes (PR3), the amido-bridged trinuclear complex [{Ir(μ-NH2)(tfbb)}3] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2-η2-4-κ-C12H8F 4N)(PR3)3], which are the products of the C-N coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to these species involves the reaction of the 18-e- complex [Ir(Cl)(tfbb)(PMePh2)2] with gaseous ammonia and additional phosphane. DFT studies show ...

  16. Cs5Sn9(OH·4NH3

    Directory of Open Access Journals (Sweden)

    Ute Friedrich


    Full Text Available The title compound, pentacaesium nonastannide hydroxide tetraammonia, crystallized from a solution of CsSnBi in liquid ammonia. The Sn94− unit forms a monocapped quadratic antiprism. The hydroxide ion is surrounded by five caesium cations, which form a distorted quadratic pyramidal polyhedron. A three-dimensional network is formed by Cs—Sn [3.8881 (7 Å to 4.5284 (7 Å] and Cs—NH3 [3.276 (7–3.636 (7 Å] contacts.

  17. A liquid-based eutectic system: LiBH4·NH 3-nNH3BH3 with high dehydrogenation capacity at moderate temperature

    KAUST Repository

    Tan, Yingbin


    A novel eutectic hydrogen storage system, LiBH4·NH 3-nNH3BH3, which exists in a liquid state at room temperature, was synthesized through a simple mixing of LiBH 4·NH3 and NH3BH3 (AB). In the temperature range of 90-110 °C, the eutectic system showed significantly improved dehydrogenation properties compared to the neat AB and LiBH 4·NH3 alone. For example, in the case of the LiBH4·NH3/AB with a mole ratio of 1:3, over 8 wt.% hydrogen could be released at 90 °C within 4 h, while only 5 wt.% hydrogen released from the neat AB at the same conditions. Through a series of experiments it has been demonstrated that the hydrogen release of the new system is resulted from an interaction of AB and the NH3 group in the LiBH4·NH3, in which LiBH4 works as a carrier of ammonia and plays a crucial role in promoting the interaction between the NH3 group and AB. The enhanced dehydrogenation of LiBH 4·NH3/AB may result from the polar liquid state reaction environments and the initially promoted formation of the diammoniate of diborane, which will facilitate the B-H⋯H-N interaction between LiBH4·NH3 and AB. Kinetics analysis revealed that the rate-controlling steps of the dehydrogenation process are three-dimensional diffusion of hydrogen at temperatures ranging from 90 to 110 °C. This journal is © The Royal Society of Chemistry.

  18. Increasing Hydrogen Density with the Cation-Anion Pair BH4−-NH4+ in Perovskite-Type NH4Ca(BH43

    Directory of Open Access Journals (Sweden)

    Pascal Schouwink


    Full Text Available A novel metal borohydride ammonia-borane complex Ca(BH42·NH3BH3 is characterized as the decomposition product of the recently reported perovskite-type metal borohydride NH4Ca(BH43, suggesting that ammonium-based metal borohydrides release hydrogen gas via ammonia-borane-complexes. For the first time the concept of proton-hydride interactions to promote hydrogen release is applied to a cation-anion pair in a complex metal hydride. NH4Ca(BH43 is prepared mechanochemically from Ca(BH42 and NH4Cl as well as NH4BH4 following two different protocols, where the synthesis procedures are modified in the latter to solvent-based ball-milling using diethyl ether to maximize the phase yield in chlorine-free samples. During decomposition of NH4Ca(BH43 pure H2 is released, prior to the decomposition of the complex to its constituents. As opposed to a previously reported adduct between Ca(BH42 and NH3BH3, the present complex is described as NH3BH3-stuffed α-Ca(BH42.

  19. Influences of the (NH2)2CO concentration on magnetic photocatalytic composites (United States)

    Liŭ, Dan; Li, Ziheng; Wang, Wenquan; Liú, Dan; Wang, Guoqiang; Lin, Junhong; He, Yingqiao; Li, Xiangru


    Magnetic photocatalytic Fe3O4@TiO2 composites have been fabricated by changing the concentration of (NH2)2CO. Samples were named as low (NH2)2CO concentration group which the (NH2)2CO concentration in the synthesis process was below 2.25 mol/L and high (NH2)2CO concentration group which the (NH2)2CO concentration was above 2.5 mol/L. Photocatalytic degradation experiments of methyl orange showed that the final degradation rates of low (NH2)2CO concentration group samples were higher than that of high (NH2)2CO concentration group, even better than P25 at the same test conditions. And it was interesting that samples of low (NH2)2CO concentration group had smaller values of BET surface areas than that of high (NH2)2CO concentration group. It indicated that the improvement of photocatalytic activity which was effected by BET surface areas was not obvious. There were two main factors enhancing the photocatalytic property of low (NH2)2CO concentration group: First, diffusing reflection spectra showed that the low (NH2)2CO concentration group samples had lower reflectivity, this suggested that the structure improved the efficiency of light absorption; Second, NH4+ would take up the active sites on the surface of the TiO2 particles, the FT-IR test results showed that the samples of the low (NH2)2CO concentration group samples bonded less NH4+, thus leading to the higher photocatalytic activity. It had enlightenment role for optimizing the performance of photocatalytic materials.

  20. Strategy for improved NH2 detection in combustion environments using an Alexandrite laser (United States)

    Brackmann, Christian; Zhou, Bo; Samuelsson, Per; Alekseev, Vladimir A.; Konnov, Alexander A.; Li, Zhongshan; Aldén, Marcus


    A new scheme for NH2 detection by means of laser-induced fluorescence (LIF) with excitation around wavelength 385 nm, accessible using the second harmonic of a solid-state Alexandrite laser, is presented. Detection of NH2 was confirmed by identification of corresponding lines in fluorescence excitation spectra measured in premixed NH3-air flames and on NH2 radicals generated through NH3 photolysis in a nonreactive flow at ambient conditions. Moreover, spectral simulations allow for tentative NH2 line identification. Dispersed fluorescence emission spectra measured in flames and photolysis experiments showed lines attributed to vibrational bands of the NH2 A2A1 ← X2B1 transition but also a continuous structure, which in flame was observed to be dependent on nitrogen added to the fuel, apparently also generated by NH2. A general conclusion was that fluorescence interferences need to be carefully considered for NH2 diagnostics in this spectral region. Excitation for laser irradiances up to 0.2 GW/cm2 did not result in NH2 fluorescence saturation and allowed for efficient utilization of the available laser power without indication of laser-induced photochemistry. Compared with a previously employed excitation/detection scheme for NH2 at around 630 nm, excitation at 385.7 nm showed a factor of 15 higher NH2 signal. The improved signal allowed for single-shot NH2 LIF imaging on centimeter scale in flame with signal-to-noise ratio of 3 for concentrations around 1000 ppm, suggesting a detection limit around 700 ppm. Thus, the presented approach for NH2 detection provides enhanced possibilities for characterization of fuel-nitrogen combustion chemistry.

  1. C-NH2 bond formation mediated by iridium complexes. (United States)

    Mena, Inmaculada; Casado, Miguel A; Polo, Víctor; García-Orduña, Pilar; Lahoz, Fernando J; Oro, Luis A


    In the presence of phosphanes (PR3 ), the amido-bridged trinuclear complex [{Ir(μ-NH2 )(tfbb)}3 ] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2-η(2) -4-κ-C12 H8 F4 N)(PR3 )3 ], which are the products of the CN coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to these species involves the reaction of the 18 e(-) complex [Ir(Cl)(tfbb)(PMePh2 )2 ] with gaseous ammonia and additional phosphane. DFT studies show that both transformations occur through nucleophilic attack. In the first case the amido moiety attacks a diolefin coordinated to a neighboring molecule following a bimolecular mechanism induced by the highly basic NH2 moiety; the second pathway involves a direct nucleophilic attack of ammonia to a coordinated tfbb molecule. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


    Energy Technology Data Exchange (ETDEWEB)

    Hickson, Kevin M.; Loison, Jean-Christophe [Université de Bordeaux, Institut des Sciences Moléculaires, UMR 5255, F-33400 Talence (France); Bourgalais, Jérémy; Capron, Michael; Picard, Sébastien D. Le [Institut de Physique de Rennes, Astrophysique de Laboratoire, UMR CNRS 6251, Université de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France); Goulay, Fabien [Department of Chemistry, West Virginia University, Morgantown, WV 26506 (United States); Wakelam, Valentine, E-mail: [Université de Bordeaux, Laboratoire d’Astrophysique de Bordeaux, UMR 5804, F-33270 Floirac (France)


    A continuous supersonic flow reactor has been used to measure rate constants for the C({sup 3}P) + NH{sub 3} reaction over the temperature range 50–296 K. C({sup 3}P) atoms were created by the pulsed laser photolysis of CBr{sub 4}. The kinetics of the title reaction were followed directly by vacuum ultra-violet laser induced fluorescence of C({sup 3}P) loss and through H({sup 2}S) formation. The experiments show unambiguously that the reaction is rapid at 296 K, becoming faster at lower temperatures, reaching a value of (1.8 ± 0.2) × 10{sup −10} cm{sup 3} molecule{sup −1} s{sup −1} at 50 K. As this reaction is not currently included in astrochemical networks, its influence on interstellar nitrogen hydride abundances is tested through a dense cloud model including gas–grain interactions. In particular, the effect of the ortho-to-para ratio of H{sub 2}, which plays a crucial role in interstellar NH{sub 3} synthesis, is examined.

  3. The interaction of NH 3 with ordered Pt surfaces (United States)

    Baetzold, R. C.; Apai, G.; Shustorovich, E.


    The interaction of ammonia with ordered Pt surface was studies by means of surface core-level photoemission and tight-binding-type calculations. Clean Pt surfaces have distinguishable surface and bulk components of the 4f 7/2 core level. The 4f 7/2 surface component is shifted to lower binding energy (-0.32 eV) than the bulk on the clean (111) surface, but in the presence of ammonia the surface peak is shifted to positive binding energy (0.7 eV). This result is unexpected, since it indicates a depletion of d-electron density on Pt atoms attached to NH 3, in contrast to common assumptions of NH 3 as a net donor. Thin-film calculations show this depletion in the form of rehybridization of sp with d electrons on the Pt atom. The mixing of p z orbitals with the d band leads to a dipole moment perpendicular to the surface, which in addition to the static dipole of ammonia is also a major factor in the decrease in work function upon chemisorption.

  4. Is CH3NH3PbI3 Polar? (United States)

    G, Sharada; Mahale, Pratibha; Kore, Bhushan P; Mukherjee, Somdutta; Pavan, Mysore S; De, Chandan; Ghara, Somnath; Sundaresan, A; Pandey, Anshu; Guru Row, Tayur N; Sarma, D D


    In view of the continued controversy concerning the polar/nonpolar nature of the hybrid perovskite system, CH3NH3PbI3, we report the first investigation of a time-resolved pump-probe measurement of the second harmonic generation efficiency as well as using its more traditional form as a sensitive probe of the absence/presence of the center of inversion in the system both in its excited and ground states, respectively. Our results clearly show that SHG efficiency, if nonzero, is below the limit of detection, strongly indicative of a nonpolar or centrosymmetric structure. Our results on the same samples, based on temperature dependent single crystal X-ray diffraction and P-E loop measurements, are entirely consistent with the above conclusion of a centrosymmetric structure for this compound in all three phases, namely the high temperature cubic phase, the intermediate temperature tetragonal phase and the low temperature orthorhombic phase. It is important to note that all our experimental probes are volume averaging and performed on bulk materials, suggesting that basic material properties of CH3NH3PbI3 are consistent with a centrosymmetric, nonpolar structure.

  5. Effective participation of Li4(NH2)3BH4 in the dehydrogenation pathway of the Mg(NH2)2-2LiH composite. (United States)

    Amica, G; Cova, F; Arneodo Larochette, P; Gennari, F C


    Lithium fast-ion conductors have shown positive effects on the hydrogen storage properties of the Li-Mg-N-H system. In the present work, Li4(NH2)3BH4 doped Mg(NH2)2-2LiH was formed by milling the 2LiNH2-MgH2-0.2LiBH4 composite and posterior annealing under hydrogen pressure to reduce the kinetic barrier of the Li-Mg-N-H system. The effect of repetitive dehydrogenation/rehydrogenation cycles on the kinetic and thermodynamic performance was evaluated. The dehydrogenation rate in the doped composite was twice that in the un-doped sample at 200 °C, while hydrogenation was 20 times faster. The activation energy decreases by 9% due to the presence of Li4(NH2)3BH4 compared to the un-doped composite, evidencing its catalytic role. The presence of Li4(NH2)3BH4 in the composite stabilized the hydrogen storage capacity after successive sorption cycles. Thermodynamic studies revealed a variation in the pressure composition isotherm curves between the first dehydrogenation cycle and the subsequent. The Li4(NH2)3BH4 doped composite showed a sloped plateau region at higher equilibrium pressure in regard to the flat plateau of the un-doped composite. Detailed structural investigations revealed the effective influence of Li4(NH2)3BH4 in different reactions: the irreversible dehydrogenation in the presence of MgH2 and the reversible hydrogen release when it reacts with Li2Mg2(NH)3. The role of Li4(NH2)3BH4 in improving the dehydrogenation kinetics is associated with the weakening of the N-H bond and the mobile small ion mass transfer enhancement.

  6. An ambient experimental study of phase equilibrium in the atmospheric system: Aerosol H +, NH 4+, SO 2-4, NO 3--NH 3(g), HNO 3(g) (United States)

    Tanner, Roger L.

    A major simplification in the quantitative modeling of the atmospheric impact of the major aerosol and gaseous sulfur and nitrogen compounds would result from demonstration of phase equilibrium between the gases NH 3, HNO 3 and the appropriate aerosol-phase ionic or molecular species in the ambient atmosphere. The phase diagram of the (NH 4) 2SO 4-H 2SO 4-H 2O and NH 4NO 3-H 2O systems have been recently refined by experimental measurements and preliminary calculations of the mixed nitrate-sulfate system have also been made. Experiments to test the applicability of existing phase equilibria considerations to the ambient atmosphere have been designed and conducted based on newly devised techniques for continuous determination of gaseous NH 3 with time resolution acid and aerosol nitrate with time resolution of ~ 15 min. Preliminary results suggest that during a daytime period with aerosol composition approximating a letovicite-NH 4NO 3 mixture, observed products of NH 3 (g) and HNO 3(g) concentrations agreed very well with the equilibrium constant calculated for the ammonium nitrate-NH 3(g), HNO 3(g) equilibrium. During a night-time period, the predicted ammonia concentrations, based on bulk aerosol composition data, were much lower and nitric acid concentrations much higher, respectively, than the observed values. The error sources in the measured and calculated values do not appear to account for the apparent deviations from gas-phase concentrations based on the droplet-pH controlling bisulfate-sulfate equilibrium.

  7. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 perovskites for solar cell applications. (United States)

    Umari, Paolo; Mosconi, Edoardo; De Angelis, Filippo


    Hybrid AMX3 perovskites (A = Cs, CH3NH3; M = Sn, Pb; X = halide) have revolutionized the scenario of emerging photovoltaic technologies, with very recent results demonstrating 15% efficient solar cells. The CH3NH3PbI3/MAPb(I(1-x)Cl(x))3 perovskites have dominated the field, while the similar CH3NH3SnI3 has not been exploited for photovoltaic applications. Replacement of Pb by Sn would facilitate the large uptake of perovskite-based photovoltaics. Despite the extremely fast progress, the materials electronic properties which are key to the photovoltaic performance are relatively little understood. Density Functional Theory electronic structure methods have so far delivered an unbalanced description of Pb- and Sn-based perovskites. Here we develop an effective GW method incorporating spin-orbit coupling which allows us to accurately model the electronic, optical and transport properties of CH3NH3SnI3 and CH3NH3PbI3, opening the way to new materials design. The different CH3NH3SnI3 and CH3NH3PbI3 electronic properties are discussed in light of their exploitation for solar cells, and found to be dominantly due to relativistic effects. These effects stabilize the CH3NH3PbI3 material towards oxidation, by inducing a deeper valence band edge. Relativistic effects, however, also increase the material band-gap compared to CH3NH3SnI3, due to the valence band energy downshift (~0.7 eV) being only partly compensated by the conduction band downshift (~0.2 eV).

  8. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 Perovskites for Solar Cell Applications (United States)

    Umari, Paolo; Mosconi, Edoardo; de Angelis, Filippo


    Hybrid AMX3 perovskites (A = Cs, CH3NH3; M = Sn, Pb; X = halide) have revolutionized the scenario of emerging photovoltaic technologies, with very recent results demonstrating 15% efficient solar cells. The CH3NH3PbI3/MAPb(I1-xClx)3 perovskites have dominated the field, while the similar CH3NH3SnI3 has not been exploited for photovoltaic applications. Replacement of Pb by Sn would facilitate the large uptake of perovskite-based photovoltaics. Despite the extremely fast progress, the materials electronic properties which are key to the photovoltaic performance are relatively little understood. Density Functional Theory electronic structure methods have so far delivered an unbalanced description of Pb- and Sn-based perovskites. Here we develop an effective GW method incorporating spin-orbit coupling which allows us to accurately model the electronic, optical and transport properties of CH3NH3SnI3 and CH3NH3PbI3, opening the way to new materials design. The different CH3NH3SnI3 and CH3NH3PbI3 electronic properties are discussed in light of their exploitation for solar cells, and found to be dominantly due to relativistic effects. These effects stabilize the CH3NH3PbI3 material towards oxidation, by inducing a deeper valence band edge. Relativistic effects, however, also increase the material band-gap compared to CH3NH3SnI3, due to the valence band energy downshift (~0.7 eV) being only partly compensated by the conduction band downshift (~0.2 eV).

  9. Nanoscale structural characterization of Mg(NH3)6Cl2 during NH3 desorption

    DEFF Research Database (Denmark)

    Jacobsen, Hjalte Sylvest; Hansen, Heine Anton; Andreasen, Jens Wenzel


    Complex metal hydrides progressively display improved hydrogen storage capacity, but they are still far from fulfilling the requirements of the transport sector. Recently, indirect storage of hydrogen as ammonia in Mg(NH3)(6)Cl-2 has shown impressive capacity and reversibility. Here, we present...... an in situ nanoscale structural characterization of the thermal decomposition of Mg(NH3)(6)Cl-2 using small angle X-ray scattering (SAXS). We observe the growth of polydisperse spherical Mg(NH3)(2)Cl-2 crystallites forming a skeletal structure, the subsequent agglomeration of MgCl2 and formation...

  10. Product energy distributions from the 193 nm photodissociation of NH 3 (United States)

    Koplitz, B.; Xu, Z.; Wittig, C.


    Product energy distributions are reported for 193 nm NH 3 photodissociation. Velocity-aligned Doppler spectroscopy on the H-atom fragment reveals a "cold" kinetic energy distribution, indicating a high degree of NH 2 internal excitation. Data are compared with the trajectory calculations of Rice, Raff and Thompson for NH 3(X˜ 1A 1) dissociation, and the reaction mechanism of Ashfold, Bennett and Dixon is discussed.

  11. Thermal Transformation of NH4-Clinoptilolite to Mullite and Silica Polymorphs


    Antonio Brundu; Guido Cerri; Eleonora Sale


    Clinoptilolite is a natural zeolite used for the abatement of ammonium in the treatment of urban wastewater. By considering that mullite was obtained through thermal treatment of NH4-exchanged synthetic zeolites, this work aimed to evaluate if this phase can be obtained from NH4-clinoptilolite. A material containing about 90 wt % of clinoptilolite, prepared using a Sardinian zeolite-rich rock, was NH4-exchanged and subjected to treatments up to 1200 °C. After dehydration, de-ammoniation, and ...

  12. Investigation on thermal evaporated CH3NH3PbI3 thin films

    Directory of Open Access Journals (Sweden)

    Youzhen Li


    Full Text Available CH3NH3I, PbI2 and CH3NH3PbI3 films were fabricated by evaporation and characterized with X-ray Photoelectron Spectroscopy (XPS and X-ray diffraction (XRD. The XPS results indicate that the PbI2 and CH3NH3PbI3 films are more uniform and stable than the CH3NH3I film. The atomic ratio of the CH3NH3I, PbI2 and CH3NH3PbI3 films are C:N:I=1.00:1.01:0.70, Pb:I= 1.00:1.91 and C: N: Pb: I = 1.29:1.07:1.00:2.94, respectively. The atomic ratio of CH3NH3PbI3 is very close to that of the ideal perovskite. Small angle x-ray diffraction results demonstrate that the as evaporated CH3NH3PbI3 film is crystalline. The valence band maximum (VBM and work function (WF of the CH3NH3PbI3 film are about 0.85eV and 4.86eV, respectively.

  13. NH4SH and cloud cover in the atmospheres of the giant planets (United States)

    Ibragimov, K. Iu.; Solodovnik, A. A.


    The probability of the formation of NH4SH and (NH4)2S is examined on the basis of the Le Chatelier principle. It is shown that it is very doubtful if NH4SH can be created in the atmospheres of the giant planets in quantities sufficient for cloud formation. Thus (NH4)2S is considered as a more likely candidate for cloud formation in the atmospheres of these planets, inasmuch as the conditions for its production there are more favorable.

  14. Formation of HCN and NH{sub 3} during Datong coal pyrolysis in arc plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Bao Wei-ren; Zhang Jin-cao; Shen Shu-guang; Cao Qing; Lu Yong-kang [Taiyuan University of Technology, Taiyuan (China). Key Laboratory of Coal Science and Technology


    The formation of HCN and NH{sub 3} from coal-N was investigated in a plasma coal pyrolysis reactor. Based on Gibbs free energy minimization principle, Thermodynamic equilibrium fraction of C-H-O-N was calculated. The results from experiments and calculation suggest that HCN is the main product of coal-N at high temperature. Only a little coal-N convertedto NH{sub 3}. As the temperature increases, the yields of HCN and NH{sub 3} increases from the experimental results, but the theoretic calculated results show that HCN gradually increases and NH{sub 3} decreases. The possible reason is the influence of practical operating condition. The yield of HCN increases firstly and then decreases with increasing coal feeding rate, but NH{sub 3} is reverse. Enhancement of input power lease to the increase of HCN and NH{sub 3} yields. H{sub 2} acting as the reactive atmosphere benefits to the formation of HCN and NH{sub 3}, and CO{sub 2} may reduce the yields of HCN and NH{sub 3}, O{sub 2} enhance the formation of NH{sub 3}, but promotes the furthermore conversion of HCN. 12 refs., 4 figs., 1 tab.

  15. CN and NH2 atmospheres of Comet C/1999 J3 (Linear) (United States)

    Korsun, P. P.; Jockers, K.


    Observations of Comet C/1999 J3 were made at the 2-m telescope of the Pik Terskol Observatory on September 19, 1999. Narrow-band CCD images of the CN, NH2, and dust atmospheres have been recorded using the two-channel focal reducer of the Max-Plank-Institute for Aeronomy. To fit distributions of the CN and NH2 molecules in the comet atmosphere Monte Carlo model was adopted. Model calculations were successful with photodissociation lifetimes equal to τCN=1.5×105s and τ{CNparent}=3.2×104s for CN and its parent, τ{NH2}=1.0×105s and τ{NH2parent}=5.0×103s for NH2 and its parent, respectively. These results are in agreement with HCN as the main source of the CN radicals and NH3 as the main source of the NH2 radicals in the atmosphere of Comet C/1999 J3 (Linear). The gas-production rates of CN, Q(CN)=3.8×1025 mol-1, and NH2, Q(NH2)=2.6×1025 mol-1, have been determined as well. These values are about 0.24% and 0.16%, respectively, of the water production rate.

  16. Absolute intensities of NH-stretching transitions in dimethylamine and pyrrole. (United States)

    Miller, Benjamin J; Du, Lin; Steel, Thomas J; Paul, Allanah J; Södergren, A Helena; Lane, Joseph R; Henry, Bryan R; Kjaergaard, Henrik G


    Vibrational spectra of vapor-phase dimethylamine (DMA) and pyrrole have been recorded in the 1000 to 13000 cm(-1) region using long path conventional spectroscopy techniques. We have focused on the absolute intensities of the NH-stretching fundamental and overtone transitions; Δν(NH) = 1-4 regions for DMA and the Δν(NH) = 1-3 regions for pyrrole. In the Δν(NH) = 1-3 regions for DMA, evidence of tunneling splitting associated with the NH-wagging mode is observed. For DMA, the fundamental NH-stretching transition intensity is weaker than the first NH-stretching overtone. Also, the fundamental NH-stretching transition in DMA is much weaker than the fundamental transition in pyrrole. We have used an anharmonic oscillator local mode model with ab initio calculated local mode parameters and dipole moment functions at the CCSD(T)/aug-cc-pVTZ level to calculate the NH-stretching intensities and explain this intensity anomaly in DMA.

  17. Toxic effects of NH4(+)-N on embryonic development of Bufo gargarizans and Rana chensinensis. (United States)

    Deng, Hongzhang; Chai, Lihong; Luo, Pingping; Zhou, Meimei; Nover, Daniel; Zhao, Xiaohong


    Although nitrogen fertilizer is commonly used worldwide, little information is currently available about NH4(+)-N toxicity on amphibians. This study determined the acute and chronic toxic effects of NH4(+)-N on two native Chinese amphibian species (Bufo gargarizans and Rana chensinensis), and compared the negative sensitivity of different embryos to NH4(+)-N. Static renewal aqueous exposures were performed using B. gargarizans and R. chensinensis embryos at Gosner stage 2 over 96 h. In terms of 96 h-LC50, B. gargarizans and R. chensinensis embryos had significantly different responses to NH4(+)-N, and the latter was more sensitive to NH4(+)-N than the former. In the chronic toxicity test, exposure to 10 mg L(-1)NH4(+)-N or higher significantly decreased the hatching rate of embryos in both species. Significant increases in the abnormality rate of embryos at 50 mg L(-1)NH4(+)-N or higher were observed and morphological abnormalities were characterized by axial flexures, yolk sac edema, and hyperplasia in both species. Additionally, the total length of embryos decreased in a dose-dependent manner after exposure to NH4(+)-N. The results indicate that NH4(+)-N exposure can increase abnormality and inhibit the hatching and development of embryos in B. gargarizans and R. chensinensis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Thermolysis and solid state NMR studies of NaB3H8, NH3B3H7, and NH4B3H8. (United States)

    Huang, Zhenguo; Eagles, Mitch; Porter, Spencer; Sorte, Eric G; Billet, Beau; Corey, Robert L; Conradi, Mark S; Zhao, Ji-Cheng


    In an effort to broaden the search for high-capacity hydrogen storage materials, three triborane compounds, NaB(3)H(8), NH(3)B(3)H(7), and NH(4)B(3)H(8), were studied. In addition to hydrogen, thermal decomposition also releases volatile boranes, and the relative amounts and species depend on the cations (Na(+), NH(4)(+)) and the Lewis base (NH(3)). Static-sample hydrogen NMR is used to probe molecular motion in the three solids. In each case, the line width decreases from low temperatures to room temperature in accordance with a model of isotropic or nearly isotropic reorientations. Such motions also explain a deep minimum in the relaxation time T(1). Translational diffusion never appears to be rapid on the 10(-5) s time scale of NMR.

  19. Determining the storage, availability and reactivity of NH3 within Cu-Chabazite-based Ammonia Selective Catalytic Reduction systems. (United States)

    Lezcano-Gonzalez, I; Deka, U; Arstad, B; Van Yperen-De Deyne, A; Hemelsoet, K; Waroquier, M; Van Speybroeck, V; Weckhuysen, B M; Beale, A M


    Three different types of NH3 species can be simultaneously present on Cu(2+)-exchanged CHA-type zeolites, commonly used in Ammonia Selective Catalytic Reduction (NH3-SCR) systems. These include ammonium ions (NH4(+)), formed on the Brønsted acid sites, [Cu(NH3)4](2+) complexes, resulting from NH3 coordination with the Cu(2+) Lewis sites, and NH3 adsorbed on extra-framework Al (EFAl) species, in contrast to the only two reacting NH3 species recently reported on Cu-SSZ-13 zeolite. The NH4(+) ions react very slowly in comparison to NH3 coordinated to Cu(2+) ions and are likely to contribute little to the standard NH3-SCR process, with the Brønsted groups acting primarily as NH3 storage sites. The availability/reactivity of NH4(+) ions can be however, notably improved by submitting the zeolite to repeated exchanges with Cu(2+), accompanied by a remarkable enhancement in the low temperature activity. Moreover, the presence of EFAl species could also have a positive influence on the reaction rate of the available NH4(+) ions. These results have important implications for NH3 storage and availability in Cu-Chabazite-based NH3-SCR systems.

  20. Limited overshooting of NH{sub 4}{sup +} ions in ammonium perchlorate; Ograniczene przeskoki jonow NH{sub 4}{sup +} w nadchloranie amonowym

    Energy Technology Data Exchange (ETDEWEB)

    Birczynski, A.; Lalowicz, Z.T. [Inst. of Nuclear Physics, Cracow (Poland); Ingman, L.P.; Punkkinen, M.; Ylinen, E.E. [Wihuri Physical Lab., Turku Univ., Turku (Finland)


    The interpretation of NMR spectra for polycrystalline sample of ammonium perchlorate in helium temperature assumes the tunneling of NH{sub 4}{sup +}. Such interpretation does not agree with experimental data. The hypothesis of additional motion (fast rotation around one of C3 axis) has been checked and discussed on the base of NMR spectra of NH{sub 4}ClO{sub 4} monocrystal for the temperature range 2.1-25 K. 9 refs, 1 fig.

  1. Vibrations and reorientations of NH3 molecules in [Mn(NH3)6](ClO4)2 studied by infrared spectroscopy and theoretical (DFT) calculations. (United States)

    Hetmańczyk, Joanna; Hetmańczyk, Łukasz; Migdał-Mikuli, Anna; Mikuli, Edward


    The vibrational and reorientational motions of NH3 ligands and ClO4(-) anions were investigated by Fourier transform middle-infrared spectroscopy (FT-IR) in the high- and low-temperature phases of [Mn(NH3)6](ClO4)2. The temperature dependencies of full width at half maximum (FWHM) of the infrared bands at: 591 and 3385cm(-1), associated with: ρr(NH3) and νas(N-H) modes, respectively, indicate that there exist fast (correlation times τR≈10(-12)-10(-13)s) reorientational motions of NH3 ligands, with a mean values of activation energies: 7.8 and 4.5kJmol(-1), in the phase I and II, respectively. These reorientational motions of NH3 ligands are only slightly disturbed in the phase transition region and do not significantly contribute to the phase transition mechanism. Fourier transform far-infrared and middle-infrared spectra with decreasing of temperature indicated characteristic changes at the vicinity of PT at TC(c)=137.6K (on cooling), which suggested lowering of the crystal structure symmetry. Infrared spectra of [Mn(NH3)6](ClO4)2 were recorded and interpreted by comparison with respective theoretical spectra calculated using DFT method (B3LYP functional, LANL2DZ ECP basis set (on Mn atom) and 6-311+G(d,p) basis set (on H, N, Cl, O atoms) for the isolated equilibrium two models (Model 1 - separate isolated [Mn(NH3)6](2+) cation and ClO4(-) anion and Model 2 - [Mn(NH3)6(ClO4)2] complex system). Calculated optical spectra show a good agreement with the experimental infrared spectra (FT-FIR and FT-MIR) for the both models. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Absorption spectroscopy of RDX monopropellant flames: CN and NH concentrations (United States)

    Homan, B. E.; Vanderhoff, John A.


    UV-visible multi-channel absorption spectroscopy has been used to probe the self-sustained combustion of pressed RDX, a main energetic ingredient found in modern day propellants and explosives. The two dimensional feature of an intensified CCD detector allowed simultaneous recording of multiple, spatially distinct absorption spectra. Between 10 and 12 equally spaced absorption spectra with spatial resolution as small as 0.163 mm have been obtained during 1 ms exposure. The number of absorption spectra and the spatial resolution can easily be set by the detector software, size of the excitation sheet and the focal length of the collection lens. Temporal resolution in the UV region has been increased to 1 ms by pulsing the light source. A 0.54 joule pulse with a duration of 0.75 ms was added to a simmering Xenon arc lamp for the measurement of combustion species. The increase in light intensity of 30 and 70 times the non-pulsed output provided the necessary light flux to achieve single pulse, multiple absorption spectra. To increase the species concentration sensitivity of the experiment, a triple pass optical arrangement was adopted. Partially silvered windows were installed at an angle to the beam providing for three passes across the samples. The corresponding path length was increased by a factor of 2.8 times the sample diameter. Least squares analysis of absorption spectra provide mole fraction profiles for OH, CN and NH along with temperature. Profiles for NC and HN have been determined for self-sustained combustion of RDX in 1.0, 1.5 and 2.0 atm air. Peak CN mole fractions of about 200 ppm are observed at 1 atm pressure and the NH mole fraction is about a factor of two lower. As the pressure is increased the reactive CN and HN species peak closer to the combusting surface and reside over a smaller spatial extent. Peak concentrations drop for these higher pressures, but may be due, at least in part, to limitations of the spatial resolution of the absorption

  3. CH3NH3I在制备CH3NH3PbI(3-x)Clx钙钛矿太阳能电池中的作用∗%Effects of CH3NH3I on fabricating CH3NH3PbI(3-x)Clx p erovskite solar cells

    Institute of Scientific and Technical Information of China (English)

    夏祥; 刘喜哲


    Perovskite solar cell, which is prepared by using the organic-inorganic hybrid halide CH3NH3PbX3 (X = I, Cl and Br), receives widespread attention because of its solution processability and high photon-to-electron conversion effi-ciency. The highest reported photon-to-electron conversion efficiency is that using CH3NH3PbI(3−x)Clx as an absorber. It is reported that the diffusion length is greater than 1 micrometer in this mixed halide perovskite. The method most commonly used in preparing CH3NH3PbI(3−x)Clx film is the one-step pyrolysis method, which has a complex reaction mechanism. In this paper, we review the work about CH3NH3PbI(3−x)Clx perovskite, in which emphasis is put on the importance of the preparation process, and analyze the role of CH3NH3I in the one-step pyrolysis method for fabricating the CH3NH3PbI(3−x)Clxperovskite layer. Scanning electron microscope images show that CH3NH3I can improve the cov-erage and crystallinity of the perovskite layer for precursors in low CH3NH3I concentrations (CH3NH3I/PbCl2=2.0 and 2.5). For precursors in high CH3NH3I concentrations (CH3NH3I/PbCl2=2.75 and 3), this change is not obvious. X-ray photoelectron spectroscopy confirms the change of coverage, and indicates that the content of Cl in CH3NH3PbI(3−x)Clx will be less than 5% for precursors with high CH3NH3I concentrations (CH3NH3I/PbCl2 >2.5). Perovskite solar cells based on CH3NH3PbI(3−x)Clx with different Cl dopant concentrations are studied by photoelectric measurements. Pho-tocurrent density-photovoltage curves show that the performance of the devices increases with the increase of CH3NH3I concentration in precursors. And the incident-photon-to-current conversion efficiency (IPCE) measurements indicate that the devices fabricated by using precursors with high CH3NH3I concentration have a relatively high external quan-tum efficiency. These results imply that only CH3NH3PbI(3−x)Clx with very low Cl dopant concentration will be effective material for

  4. Time Resolved Measurement of Ecosystem-Atmosphere NH3 Exchange Using the Eddy Covariance Technique (United States)

    Fischer, M. L.; Littlejohn, D.


    Quantifying ammonia fluxes between the land surface and atmosphere is required for effective control of air quality, improving agricultural practices, and understanding natural ecosystem function. Ammonia (NH3) is emitted in large but uncertain amounts from animal agriculture, in lesser amounts from imperfect use of nitrogen fertilizers in crop agriculture, from catalytic converters used on automobiles and other energy related industrial processes, and exchanged between the ecosystem and atmosphere by natural ecosystem processes on vast spatial scales. To address the need for accurate, time-resolved NH3 flux measurements, we have developed an eddy covariance (EC) instrument for direct measurements of NH3 flux. EC flux measurements of NH3 were not previously possible because instruments were not sufficiently sensitive at high frequencies required to capture rapid variations in surface layer NH3 concentrations. To overcome this hurdle we combined a tunable-diode-laser (TDL) spectrometer with a fast-response NH3 sampling inlet and automated pulse-response calibration system. Laboratory tests of the inlet system demonstrate that the response to 10 ppb step in NH3 concentration is well described by a double exponential model with (1/e) times of 0.3 (85% response) and 1.5 (15% response) seconds. This response combined with a routinely measured instrument stability of ~ 0.1 ppb (on 30 minute timescales) indicates that the instrumental contribution to noise in NH3 flux measurements is ~ 0.2 umol NH3 m-2 hr-1, sufficient to stringently test models for NH3 exchange under most conditions. Recent results of field work to verify the instrument performance and observe examples of NH3 exchange will be presented.

  5. Infrared spectrum of the cold ortho-fluorinated protonated neurotransmitter 2-phenylethylamine: competition between NH(+)π and NH(+)F interactions. (United States)

    Schütz, Markus; Bouchet, Aude; Dopfer, Otto


    Halogenation of pharmaceutical molecules is a common tool to modify their physiological properties. The geometric, vibrational, and electronic properties of the ortho-fluorinated protonated neurotransmitter 2-phenylethylamine (oF-H(+)PEA) are characterized by infrared photodissociation (IRPD) spectroscopy in the NH stretch range using the messenger technique and dispersion-corrected density functional theory calculations at the B3LYP-D3/aug-cc-pVTZ level to elucidate the drastic effect of site-specific ortho-fluorination. The IRPD spectra of cold oF-H(+)PEA-Rg dimers (Rg = Ne, Ar) are assigned to the most stable gauche conformer (Gf1) of oF-H(+)PEA, which benefits from both NH(+)π and NH(+)F interactions. A minor contribution (∼5%) of the slightly less stable Gf2 gauche conformer (E0 = +1.1 kJ mol(-1)) is also identified. Comparison of oF-H(+)PEA with unsubstituted H(+)PEA reveals a much stronger NH(+)π interaction in H(+)PEA resulting in a large red shift of the bonded NH stretch frequency. This behavior is confirmed by natural bond orbital (NBO) analysis and noncovalent interaction (NCI) calculations. The Rg ligand prefers a binding site at which it can maximize the interaction with the aromatic π electron system and the ammonium group. Although the intermolecular interactions with the Rg atoms can compete with the noncovalent intramolecular bonds, they induce only minor spectral shifts in the NH stretch range.

  6. Properties of oxidized linen fiber grafted with HBP-NH2%HBP-NH2接枝氧化亚麻纤维性能研究

    Institute of Scientific and Technical Information of China (English)

    赵兵; 张峰; 林红; 陈宇岳



  7. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib


    temperatures and a low NH3-to-H2 ratio, the catalytic activity of the best Ni-Fe/Al2O3 catalyst was found to be comparable or even better to that of a more expensive Ru-based catalyst. Small Ni-Fe nanoparticle sizes are crucial for an optimal overall NH3 conversion because of a structural effect favoring...

  8. Adsorption of NH2 on Graphene in the Presence of Defects and Adsorbates (United States)


    only NH2 adsorbates are present. To understand the variation of adsorption energy of secondary NH2 with distance, we recall that the primitive cell of...graphene contains two carbon atoms and forms a bipartite lattice.29,30 Lattice sites related to these two different atoms of the primitive cell by

  9. NH4+ triggers the release of astrocytic lactate via mitochondrial pyruvate shunting (United States)

    Lerchundi, Rodrigo; Fernández-Moncada, Ignacio; Contreras-Baeza, Yasna; Sotelo-Hitschfeld, Tamara; Mächler, Philipp; Wyss, Matthias T.; Stobart, Jillian; Baeza-Lehnert, Felipe; Alegría, Karin; Weber, Bruno; Barros, L. Felipe


    Neural activity is accompanied by a transient mismatch between local glucose and oxygen metabolism, a phenomenon of physiological and pathophysiological importance termed aerobic glycolysis. Previous studies have proposed glutamate and K+ as the neuronal signals that trigger aerobic glycolysis in astrocytes. Here we used a panel of genetically encoded FRET sensors in vitro and in vivo to investigate the participation of NH4+, a by-product of catabolism that is also released by active neurons. Astrocytes in mixed cortical cultures responded to physiological levels of NH4+ with an acute rise in cytosolic lactate followed by lactate release into the extracellular space, as detected by a lactate-sniffer. An acute increase in astrocytic lactate was also observed in acute hippocampal slices exposed to NH4+ and in the somatosensory cortex of anesthetized mice in response to i.v. NH4+. Unexpectedly, NH4+ had no effect on astrocytic glucose consumption. Parallel measurements showed simultaneous cytosolic pyruvate accumulation and NADH depletion, suggesting the involvement of mitochondria. An inhibitor-stop technique confirmed a strong inhibition of mitochondrial pyruvate uptake that can be explained by mitochondrial matrix acidification. These results show that physiological NH4+ diverts the flux of pyruvate from mitochondria to lactate production and release. Considering that NH4+ is produced stoichiometrically with glutamate during excitatory neurotransmission, we propose that NH4+ behaves as an intercellular signal and that pyruvate shunting contributes to aerobic lactate production by astrocytes. PMID:26286989

  10. Synthesis, structure and magnetic properties of the polyoxovanadate cluster [Zn2(NH2(CH2)2NH2)5][{Zn(NH2(CH2)2NH2)2}2{V18O42(H2O)}]$\\cdot x$H2O ( ∼ 12), possessing a layered structure

    Indian Academy of Sciences (India)

    Srinivasan Natarajan; K S Narayan; Swapan K Pati


    A hydrothermal reaction of a mixture of ZnCl2, V2O5, ethylenediamine and water gave rise to a layered poly oxovanadate material [Zn2(NH2(CH2)2NH2)5][{Zn(NH2(CH2)2NH2)2}2{V18O42(H2O)}]$\\cdot x$H2O ( = 12) (I) consisting of [V18O42]12- clusters. These clusters, with all the vanadium ions in the +4 state, are connected together through Zn(NH2(CH2)2NH2)2 linkers forming a two-dimensional structure. The layers are also separated by distorted trigonal bipyramidal [Zn2(NH2(CH2)2NH2)5] complexes. The structure, thus, presents a dual role for the Zn-ethylenediamine complex. The magnetic susceptibility studies indicate that the interactions between the V centres in I are predominantly antiferromagnetic in nature and the compound shows highly frustrated behaviour. The magnetic properties are compared to the theoretical calculations based on the Heisenberg model, in addition to correlating to the structure. Crystal data for the complexes are presented.

  11. Arbuscular mycorrhiza maintains nodule function during external NH4+ supply in Phaseolus vulgaris (L.). (United States)

    Mortimer, Peter E; Pérez-Fernández, Maria A; Valentine, Alex J


    The synergistic benefits of the dual inoculation of legumes with nodule bacteria and arbuscular mycorrhizae (AM) are well established, but the effect of an external NH(4)(+) supply on this tripartite relationship is less clear. This effect of NH(4)(+) supply was investigated with regards to the growth and function of the legume host and both symbionts. Nodulated Phaseolus vulgaris seedlings with and without AM, were grown in a sand medium with either 0 N, 1 mM or 3 mM NH(4)(+). Plants were harvested at 30 days after emergence and measurements were taken for biomass, N(2) fixation, photosynthesis, asparagine concentration, construction costs and N nutrition. The addition of NH(4)(+) led to a decline in the percentage AM colonization and nodule dry weights, although AM colonization was affected to a lesser extent. NH(4)(+) supply also resulted in a decrease in the reliance on biological nitrogen fixation (BNF); however, the AM roots maintained higher levels of NH(4)(+) uptake than their non-AM counterparts. Furthermore, the non-AM plants had a higher production of asparagine than the AM plants. The inhibitory effects of NH(4)(+) on nodule function can be reduced by the presence of AM at moderate levels of NH(4)(+) (1 mM), via improving nodule growth or relieving the asparagine-induced inhibition of BNF. © Springer-Verlag 2011

  12. Identification of a transport mechanism for NH4+ in the symbiosome membrane of pea root nodules

    DEFF Research Database (Denmark)

    Mouritzen, P.; Rosendahl, L.


    Symbiosome membrane vesicles, facing bacteroid-side-out, were purified from pea (Pisum sativum L.) root nodules and used to study NH4+ transport across the membrane by recording vesicle uptake of the NH4+ analog [C-14]methylamine (MA). Membrane potentials (Delta psi) were imposed on the vesicles...

  13. Effect of activated NH3 on SO2 removal by pulse coronadischarge plasma in flue gas

    Institute of Scientific and Technical Information of China (English)


    NH3-activated electrode is placed in front of the electrode system of pulse corona discharge plasma. There are nozzles on the electrode. Positive DC high-voltage is applied on the nozzle-plate gap. NH3 is injected into the reactor through nozzles, at the same time, activated and treated. Tbese nozzles were proposed in order to make the additional gas pass through corona discharge regions near the tip of nozzles and increase the mount of radicals. The aim is to improve the De-SO2 efficiency by pulse discharge plasma in flue gas. The following topics are investigated and discussed in the paper: De-SO2 effect of single NH3-activated electrode, De-SO2 effect of activated NH3, the relationship between stoichiometric ratio of NH3 to SO2 and De-SO2 effect of activated NH3, mechanism of activated NH3 De-SO2 effect. The experimental result indicates that the De-SO2 efficiency can be increased 5 %-10 96 by activated NH3 on the original base of De-SO2 efficiency.

  14. Draft Genome Sequence of Bordetella avium Nh1210, an Outbreak Strain of Lockjaw Syndrome. (United States)

    Moreno, Luisa Z; Knöbl, Terezinha; Grespan, André A; Felizardo, Maria R; Gomes, Cleise R; Ferreira, Thais S P; Xavier de Oliveira, Maria Gabriela; Myriantheus, Livia; Moreno, Andrea Micke


    Bordetella avium is a highly contagious bacterium that infects the upper respiratory tract of birds. B. avium Nh1210 is an outbreak strain of lockjaw syndrome in juvenile cockatiel chicks (Nymphicus hollandicus). Here, we report the draft genome sequence of strain Nh1210. Copyright © 2015 Moreno et al.

  15. Survey Observations of a Possible Glycine Precursor, Methanimine (CH$_2$NH)

    CERN Document Server

    Suzuki, Taiki; Hirota, Tomoya; Saito, Masao; Majumdar, Liton; Wakelam, Valentine


    We conducted survey observations of a glycine precursor, methanimine or methylenimine (CH$_2$NH), with the NRO 45 m telescope and the SMT telescope towards 12 high-mass and two low-mass star-forming regions in order to increase number of CH$_2$NH sources and to better understand the characteristics of CH2NH sources. As a result of our survey, CH$_2$NH was detected in eight sources, including four new sources. The estimated fractional abundances were ~10$^8$ in Orion KL and G10.47+0.03, while they were ~10$^9$ towards the other sources. Our hydrogen recombination line and past studies suggest that CH$_2$NH-rich sources have less evolved HII regions. The less destruction rates by UV flux from the central star would be contributed to the high CH$_2$NH abundances towards CH$_2$NH-rich sources. Our gas-grain chemical simulations suggest that CH$_2$NH is mostly formed in the gas-phase by neutral-neutral reactions rather than the product of thermal evaporation from the dust surfaces.

  16. Role of NH3 in the Electron-Induced Reactions of Adsorbed and Solid Cisplatin

    NARCIS (Netherlands)

    Warneke, Jonas; Rohdenburg, Markus; Zhang, Yucheng; Orzagh, Juraj; Vaz, Alfredo; Utke, Ivo; De Hosson, Jeff Th M.; van Dorp, Willem F.; Swiderek, Petra


    The electron-induced decomposition of cisplatin (cis-Pt(NH3)(2)Cl-2) was investigated to reveal if ammine (NH3) ligands have a favorable effect on the purity of deposits produced from metal-containing precursor molecules by focused electron beam induced deposition (FEBID). Scanning electron microsco

  17. Molecular beam epitaxy of GaN(0001) utilizing NH{sub 3} and/or NH{sup +}{sub {ital x}} ions: Growth kinetics and defect structure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, N.; Powell, R.C.; Kim, Y.; Greene, J.E. [Materials Science Department, the Coordinated Science Laboratory, and the Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)


    Gas-source molecular beam epitaxy (GS-MBE), utilizing Ga and NH{sub 3}, and reactive-ion MBE (RIMBE), incorporating both thermal NH{sub 3} and low-energy NH{sup +}{sub {ital x}} ions, were used to grow single crystal GaN(0001) layers on Al{sub 2}O{sub 3}(0001) at temperatures {ital T}{sub {ital s}} between 700 and 850 {degree}C with deposition rates of 0.2--0.5 {mu}m h{sup {minus}1}. The RIMBE experiments were carried out with incident NH{sup +}{sub {ital x}}/Ga flux ratios {ital J}{sub NH{sup +}{sub {ital x}}}/{ital J}{sub Ga}=1.9--3.2 and NH{sup +}{sub {ital x}} acceleration energies {ital E}{sub NH{sup +}{sub {ital x}}}=45--90 eV. Plan-view and cross-sectional transmission electron microscopy analyses showed that the primary defects in the GS-MBE films were threading dislocations having either pure edge or mixed edge/screw characteristics with Burgers vectors {bar b}=1/3{l_angle}2{bar 1}{bar 1}0{r_angle}, basal-plane stacking faults with displacement vectors {bar R}=1/6{l_angle}02{bar 2}3{r_angle}, and prismatic stacking faults with {bar R}=1/2{l_angle}{bar 1}101{r_angle}. In the case of RIMBE films, no stacking faults or residual ion-induced defects were observed with {ital E}{sub NH{sup +}{sub {ital x}}}=45 eV and {ital T}{sub {ital s}}{ge}800 {degree}C. However, increasing {ital E}{sub NH{sup +}{sub {ital x}}} to {ge}60 eV at {ital T}{sub {ital s}}=800 {degree}C gave rise to the formation of residual ion-induced point-defect clusters observable by transmission electron microscopy (TEM). Increasing {ital T}{sub {ital s}} to 850 {degree}C with {ital E}{sub NH{sup +}{sub {ital x}}}{ge}60 eV resulted in the ion-induced defects aggregating to form interstitial basal and prismatic dislocation loops, whose number densities depended upon the ion flux, with Burgers vectors 1/2{l_angle}0001{r_angle} and 1/3{l_angle}2{bar 1}{bar 1}0{r_angle}, respectively. (Abstract Truncated)

  18. Crystal Structure Studies on p-Substitutedbenzenesulphonamides 4-X-C6H4SO2NH2 (X = CH3, NH2 F, Cl or Br) (United States)

    Thimme Gowda, B.; Jyothi, K.; Kožíšek, Jozef; Fuess, Hartmut


    Effect of ring substitution on the crystal structures of p-substitutedbenzenesulphonamides, p-XC6H4SO2NH2 (X = F, Cl, Br, CH3 or NH2) has been studied by determining the crystal structures of 4-chlorobenzenesulphonamide (4-ClC6H4SO2NH2) and 4-bromobenzenesulphonamide (4-BrC6H4SO2NH2) and analyzing the results along with the structures of 4-methylbenzenesulphonamide (4-CH3C6H4SO2NH2), 4-fluorobenzene-sulphonamide (4-FC6H4SO2NH2) and 4-aminobenzenesulphonamide (4-NH2C6H4SO2NH2). The crystal type, space group, formula units and lattice constants in Å of new structures are: (4-ClC6H4SO2NH2); monoclinic, P21/n, Z = 4, a = 6.6276(10), b = 16.219(3), c = 7.5716(10), β = 93.387(14)°; (4-BrC6H4SO2NH2): monoclinic, P 21/n, Z = 4, a = 6.5660(10), b = 16.4630(10), c = 7.6900(10), β = 92.760(10)°. Orientation of the amine group with respect to the phenyl ring is given by the torsion angles C(2)-C(1)-S-N: 70.9° and C(6)-C(1)-S-N: -108.5°. Similarly, the orientation of S, O(1) and O(2) with respect to the ring are given by torsion angles. The comparison of bond lengths and bond angles of 4-fluoro-, 4-chloro-, 4-bromo-, 4-methyl- and 4-amino-benzenesulphonamides reveal that the S-N and C-S bond lengths decrease with the introduction of electron-withdrawing substituents such as F, Cl or Br, while these groups do not have significant effects on the S-O distances. The effect on ring C-C distances was not uniform. Substitution of F, Cl or Br decreases the O-S-N bond angle, but increases the O-S-N, N-S-C(1) and C(3)-C(4)-C(5) bond angles.

  19. Rotational spectrum of the NH3–He van der Waals complex

    Directory of Open Access Journals (Sweden)

    Surin L.


    Full Text Available The interaction between ammonia and helium has attracted considerable interest over many years, partly because of the observation of interstellar ammonia. The rate coefficients of NH3–He scattering are an important ingredient for numerical modeling of astrochemical environments. Another, though quite different application in which the NH3–He interaction can play an important role is the doping of helium clusters with NH3 molecules to perform high-resolution spectroscopy. Such experiments are directed on the detection of non-classical response of molecular rotation in helium clusters addressing fundamental questions related to the microscopic nature of superfluidity. High-resolution spectroscopy on the NH3–He complex is an important tool for increasing our understanding of intermolecular forces between NH3 and He.


    Institute of Scientific and Technical Information of China (English)

    Q.Qu; C.W.Yan; L.Li; L.Zhang; G.H.Liu; C.N.Cao


    Influence of NH4 Cl on the initial atmospheric corrosion of zinc was investigated via quartz crystal microbalance(QCM)in laboratory at 80%RH and 25℃.The results show that NH4 Cl can accelerate the initial corrosion of zinc.Mass gain increase with the exposure time,but mass gain in the later doesn't change obviously due to the formation of the insoluble simonkolleite on zinc surface in the presence of NH4 Cl.Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)was used to characterize the corrosion products.Zn5 Cl2(OH)s.H2 O,(NH4)2ZnCl4 and ZnO are the corrosion products on zinc.Brief discussion on the mechanisms of atmospheric corrosion of zinc in the presence of NH4 Cl was introduced.

  1. NMR Spectroscopic Characterization of Methylcobalt(III) Compounds with Classical Ligands. Crystal Structures of [Co(NH(3))(5)(CH(3))]S(2)O(6), trans-[Co(en)(2)(NH(3))(CH(3))]S(2)O(6) (en = 1,2-Ethanediamine), and [Co(NH(3))(6)]-mer,trans-[Co(NO(2))(3)(NH(

    DEFF Research Database (Denmark)

    Kofod, Pauli; Harris, Pernille; Larsen, Sine


    magnetic resonance spectroscopy and by absorption spectroscopy. Single-crystal X-ray structure determinations at 122.0(5) K were performed on [Co(NH(3))(5)(CH(3))]S(2)O(6) (1), trans-[Co(en)(2)(NH(3))(CH(3))]S(2)O(6) (2), and [Co(NH(3))(6)]-mer,trans-[Co(NO(2))(3)(NH(3))(2)(CH(3))](2)-trans-[Co(NO(2...... to the trans ligand is 0.170 Å in the trans-[Co(en)(2)(NH(3))(CH(3))](2+) cation. The structural trans influence appears to decrease with the overall charge of the coordination compound. Estimates of the scalar one-bond cobalt-carbon coupling constants, (1)J(Co)(-)(C), in the pentacyanomethylcobalt(III) anion...

  2. Rotational spectrum of the NH3-He van der Waals complex (United States)

    Surin, L.; Schnell, M.


    The interaction between ammonia and helium has attracted considerable interest over many years, partly because of the observation of interstellar ammonia. The rate coefficients of NH3-He scattering are an important ingredient for numerical modeling of astrochemical environments. Another, though quite different application in which the NH3-He interaction can play an important role is the doping of helium clusters with NH3 molecules to perform high-resolution spectroscopy. Such experiments are directed on the detection of non-classical response of molecular rotation in helium clusters addressing fundamental questions related to the microscopic nature of superfluidity. High-resolution spectroscopy on the NH3-He complex is an important tool for increasing our understanding of intermolecular forces between NH3 and He.

  3. NH4+-stimulated and -inhibited components of K+ transport in rice (Oryza sativa L.) (United States)

    Szczerba, Mark W.; Britto, Dev T.; Ali, Shabana A.; Balkos, Konstantine D.; Kronzucker, Herbert J.


    The disruption of K+ transport and accumulation is symptomatic of NH4+ toxicity in plants. In this study, the influence of K+ supply (0.02–40 mM) and nitrogen source (10 mM NH4+ or NO3–) on root plasma membrane K+ fluxes and cytosolic K+ pools, plant growth, and whole-plant K+ distribution in the NH4+-tolerant plant species rice (Oryza sativa L.) was examined. Using the radiotracer 42K+, tissue mineral analysis, and growth data, it is shown that rice is affected by NH4+ toxicity under high-affinity K+ transport conditions. Substantial recovery of growth was seen as [K+]ext was increased from 0.02 mM to 0.1 mM, and, at 1.5 mM, growth was superior on NH4+. Growth recovery at these concentrations was accompanied by greater influx of K+ into root cells, translocation of K+ to the shoot, and tissue K+. Elevating the K+ supply also resulted in a significant reduction of NH4+ influx, as measured by 13N radiotracing. In the low-affinity K+ transport range, NH4+ stimulated K+ influx relative to NO3– controls. It is concluded that rice, despite its well-known tolerance to NH4+, nevertheless displays considerable growth suppression and disruption of K+ homeostasis under this N regime at low [K+]ext, but displays efficient recovery from NH4+ inhibition, and indeed a stimulation of K+ acquisition, when [K+]ext is increased in the presence of NH4+. PMID:18653690

  4. Effect of Potassium and C/N Ratios on Conversion of NH+4 in Soils

    Institute of Scientific and Technical Information of China (English)

    TANG Yan; WANG Xiao-Zhi; ZHAO Hai-Tao; FENG Ke


    Two soils, one consisting of 1:1 clay minerals at pH 4.5 and the other containing 2:1 clay minerals at pH 7.0, were used to estimate the conversion of added NH+4 under different C/N ratios (glucose as the C source) and the addition of potassium. Under lower C/N ratios (0:1 and 5:1), a large part of the added NH+4 in the acid soil was held in the forms of either exchangeable or water soluble NH+4 for a relatively long time and under higher C/N ratio (50:1), a large amount of the added NH+4 was directly immobilized by microorganisms. In the second soil containing appreciable 2:1 type clay minerals a large part of the added NH+4 at first quickly entered the interlayer of the minerals under both lower and higher C/N ratios. In second condition, however, owing to microbial assimilation stimulated by glucose the newly fixed NH+4 could be completely released in further incubation because of a large concentration gradicnt between external NH+4 and fixed NH+4 in the mineral interlayer caused by heterotrophic microorganisms, which imply the fixed NH+4 to be available to plants. The results also showed that if a large amount of K+ with carbon source together was added to soil, the higher K+ concentration of soil solution could impede the release of fixed NH+4, even if there was a lot of carbon source.

  5. Removing Gaseous NH3 Using Biochar as an Adsorbent

    Directory of Open Access Journals (Sweden)

    Kyoung S. Ro


    Full Text Available Ammonia is a major fugitive gas emitted from livestock operations and fertilization production. This study tested the potential of various biochars in removing gaseous ammonia via adsorption processes. Gaseous ammonia adsorption capacities of various biochars made from wood shaving and chicken litter with different thermal conditions and activation techniques were determined using laboratory adsorption column tests. Ammonia adsorption capacities of non-activated biochars ranged from 0.15 to 5.09 mg·N/g, which were comparable to that of other commercial activated carbon and natural zeolite. There were no significant differences in ammonia adsorption capacities of steam activated and non-activated biochars even if the surface areas of the steam activated biochars were about two orders of magnitude greater than that of non-activated biochars. In contrast, phosphoric acid activation greatly increased the biochar ammonia adsorption capacity. This suggests that the surface area of biochar did not readily control gaseous NH3 adsorption. Ammonia adsorption capacities were more or less linearly increased with acidic oxygen surface groups of non-activated and steam-activated biochars. Phosphoric acid bound to the acid activated biochars is suspected to contribute to the exceptionally high ammonia adsorption capacity. The sorption capacities of virgin and water-washed biochar samples were not different, suggesting the potential to regenerate spent biochar simply with water instead of energy- and capital-intensive steam. The results of this study suggest that non-activated biochars can successfully replace commercial activated carbon in removing gaseous ammonia and the removal efficiency will greatly increase if the biochars are activated with phosphoric acid.

  6. Simultaneous removal of H2S and NH3 in biofilter inoculated with Acidithiobacillus thiooxidans TAS. (United States)

    Lee, Eun Young; Cho, Kyung-Suk; Ryu, Hee Wook


    H2S and NH3 gases are toxic, corrosive and malodorous air pollutants. Although there are numerous well-established physicochemical techniques presently available for the treatment of these gases, the growing demand for a more economical and improved process has prompted investigations into biological alternatives. In biological treatment methods, H2S is oxidized to SO4(2-) by sulfur-oxidizing bacteria, and then NH3 is removed by chemical neutralization with SO4(2-) to (NH4)2SO4. Since the accumulated (NH4)2SO4 can inhibit microbial activity, it is important to utilize an effective sulfur-oxidizing bacterium that has tolerance to high concentrations of (NH4)2SO4 for the simultaneous removal of H2S and NH3. In this study, a sulfur-oxidizing bacterium with tolerance to high concentrations of (NH4)2SO4 was isolated from activated sludge and identified as Acidithiobacillus thiooxidans TAS. A. thiooxidans TAS could display its sulfur-oxidizing activity in a medium supplemented with 60 g.l(-1) (NH4)2SO4, even though its growth and sulfur-oxidizing activity were completely inhibited in 80 g.l(-1) (NH4)2SO4. When H2S alone was supplied to a ceramic biofilter inoculated with A. thiooxidans TAS, an almost 100% H2S removal efficiency was maintained until the inlet H2S concentration was increased up to 900 microl.l(-1) and the space velocity up to 500 h(-1), at which the amount of H2S eliminated was 810 g-S.m(-3).h(-1). However, when NH3 (50-500 microl.l(-1)) was simultaneously supplied to the biofilter with H2S, the maximum amount of H2S eliminated decreased to 650 g-S.m(-3).h(-1). The inhibition of H2S removal by low NH3 concentrations (50-200 microl.l(-1)) was similar to that by high NH3 concentrations (300-500 microl.l(-1)). The critical inlet H2S load that resulted in over 99% removal was determined as 400 g-S.m(-3).h(-1) in the presence of NH3.

  7. Synthesis of 15N-enriched urea (CO(15NH22 from 15NH3, CO, and S in a discontinuous process

    Directory of Open Access Journals (Sweden)

    C. R. Sant Ana Filho


    Full Text Available CO(15NH22 enriched with the stable isotope 15N was synthesized based on a reaction involving CO, 15NH3, and S in the presence of CH3OH. The method differs from the industrial method; a stainless steel reactor internally lined with polytetrafluoroethylene (PTFE was used in a discontinuous process under low pressure and temperature. The yield of the synthesis was evaluated as a function of the parameters: the amount of reagents, reaction time, addition of H2S, liquid solution and reaction temperature. The results showed that under optimum conditions (1.36, 4.01, and 4.48 g of 15NH3, CO, and S, respectively, 40 ml CH3OH, 40 mg H2S, 100 ºC and 120 min of reaction 1.82 g (yield 76.5% of the compound was obtained per batch. The synthesized CO(15NH22 contained 46.2% N, 0.55% biuret, melting point of 132.55 ºC and did not exhibit isotopic fractionation. The production cost of CO(15NH22 with 90.0 at. % 15N was US$ 238.60 per gram.

  8. Thermal decomposition of NH2OH and subsequent reactions: ab initio transition state theory and reflected shock tube experiments. (United States)

    Klippenstein, S J; Harding, L B; Ruscic, B; Sivaramakrishnan, R; Srinivasan, N K; Su, M-C; Michael, J V


    Primary and secondary reactions involved in the thermal decomposition of NH2OH are studied with a combination of shock tube experiments and transition state theory based theoretical kinetics. This coupled theory and experiment study demonstrates the utility of NH2OH as a high temperature source of OH radicals. The reflected shock technique is employed in the determination of OH radical time profiles via multipass electronic absorption spectrometry. O-atoms are searched for with atomic resonance absorption spectrometry. The experiments provide a direct measurement of the rate coefficient, k1, for the thermal decomposition of NH2OH. Secondary rate measurements are obtained for the NH2 + OH (5a) and NH2OH + OH (6a) abstraction reactions. The experimental data are obtained for temperatures in the range from 1355 to 1889 K and are well represented by the respective rate expressions: log[k/(cm3 molecule(-1) s(-1))] = (-10.12 +/- 0.20) + (-6793 +/- 317 K/T) (k1); log[k/(cm3 molecule(-1) s(-1))] = (-10.00 +/- 0.06) + (-879 +/- 101 K/T) (k5a); log[k/(cm3 molecule(-1) s(-1))] = (-9.75 +/- 0.08) + (-1248 +/- 123 K/T) (k6a). Theoretical predictions are made for these rate coefficients as well for the reactions of NH2OH + NH2, NH2OH + NH, NH + OH, NH2 + NH2, NH2 + NH, and NH + NH, each of which could be of secondary importance in NH2OH thermal decomposition. The theoretical analyses employ a combination of ab initio transition state theory and master equation simulations. Comparisons between theory and experiment are made where possible. Modest adjustments of predicted barrier heights (i.e., by 2 kcal/mol or less) generally yield good agreement between theory and experiment. The rate coefficients obtained here should be of utility in modeling NOx in various combustion environments.

  9. Quinone-modified NH2-MIL-101(Fe) composite as a redox mediator for improved degradation of bisphenol A. (United States)

    Li, Xianghui; Guo, Weilin; Liu, Zhonghua; Wang, Ruiqin; Liu, Hua


    A novel quinone-modified metal-organic frameworks NH2-MIL-101(Fe) was synthesized using a simple chemical method under mild condition. The introduced 2-anthraquinone sulfonate (AQS) can be covalently modified with NH2-MIL-101(Fe) and acts as a redox mediator to enhance the degradation of bisphenol A (BPA) via persulfate activation. The obtained AQS-NH-MIL-101(Fe) was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra, cyclic voltammetry and electrochemical impedance spectroscopy. AQS-NH-MIL-101(Fe) exhibited better catalytic performance compared with NH2-MIL-101(Fe) and NH2-MIL-101(Fe) with free AQS (NH2-MIL-101(Fe)/AQS). That is, AQS-NH-MIL-101(Fe) was proved to be the most effective in that more than 97.7% of BPA was removed. The degradation rate constants (k) of AQS-NH-MIL-101(Fe) was 9-fold higher than that of NH2-MIL-101(Fe) and 7-fold higher than NH2-MIL-101(Fe)/AQS, indicating that AQS is a great electron-transfer mediator when modified with NH2-MIL-101(Fe). Based on the above results, the possible mechanism of catalytic reaction has been investigated in view of the trapping experiments. In addition, the AQS-NH-MIL-101(Fe) catalyst exhibited excellent stability and can be used several times without significant deterioration in performance.

  10. Dynamics and fragmentation of van der Waals and hydrogen bonded cluster cations: (NH3)n and (NH3BH3)n ionized at 10.51 eV (United States)

    Yuan, Bing; Shin, Joong-Won; Bernstein, Elliot R.


    A 118 nm laser is employed as a high energy, single photon (10.51 eV/photon) source for study of the dynamics and fragmentation of the ammonia borane (NH3BH3) cation and its cluster ions through time of flight mass spectrometry. The behavior of ammonia ion and its cluster ions is also investigated under identical conditions in order to explicate the ammonia borane results. Charge distributions, molecular orbitals, and spin densities for (NH3BH3)n and its cations are explored at both the second-order perturbation theory (MP2) and complete active space self-consistent field (CASSCF) theory levels. Initial dissociation mechanisms and potential energy surfaces for ionized NH3BH3, NH3, and their clusters are calculated at the MP2/6-311++G(d,p) level. Protonated clusters (NH3)xH+ dominate ammonia cluster mass spectra: our calculations show that formation of (NH3)n-1H+ and NH2 from the nascent (NH3)n+ has the lowest energy barrier for the system. The only common features for the (NH3)n+ and (NH3BH3)n+ mass spectra under these conditions are found to be NHy+ (y = 0,…,4) at m/z = 14-18. Molecular ions with both 11B and 10B isotopes are observed, and therefore, product ions observed for the (NH3BH3)n cluster system derive from (NH3BH3)n clusters themselves, not from the NH3 moiety of NH3BH3 alone. NH3BH2+ is the most abundant ionization product in the (NH3BH3)n+ cluster spectra: calculations support that for NH3BH3+, an H atom is lost from the BH3 moiety with an energy barrier of 0.67 eV. For (NH3BH3)2+ and (NH3BH3)3+ clusters, a Bδ+⋯Hδ-⋯δ-H⋯δ+B bond can form in the respective cluster ions, generating a lower energy, more stable ion structure. The first step in the (NH3BH3)n+ (n = 2, 3) dissociation is the breaking of the Bδ+⋯Hδ-⋯δ-H⋯δ+B moiety, leading to the subsequent release of H2 from the latter cluster ion. The overall reaction mechanisms calculated are best represented and understood employing a CASSCF natural bond orbital

  11. Perovskite CH3NH3PbI3 crystals and films. Synthesis and characterization (United States)

    Semenova, O. I.; Yudanova, E. S.; Yeryukov, N. A.; Zhivodkov, Y. A.; Shamirzaev, T. S.; Maximovskiy, E. A.; Gromilov, S. A.; Troitskaia, I. B.


    Synthesis of organometal halide perovskite CH3NH3PbI3 has received much attention recently because of promising photosensitive properties usable for solid state solar cell (SSSC). Here the crystals of tetragonal phase (I4/mcm, a =8.8743 Å, c =12.6708 Å) of CH3NH3PbI3 were prepared. Formation of the CH3NH3PbI3 crystals was controlled by the SEM, EDS, XRD and Raman spectroscopy. Optical characteristics of the crystals were obtained using PL spectrometry and spectral ellipsometry methods. PL spectra of orthorhombic phase of CH3NH3PbI3 crystals were recorded the first time. Taking into account the practice use, the CH3NH3PbI3 films are obtained via the sol-gel method with ;spin-on; coating of CH3NH3PbI3 sol. The films are 500 nm in thickness and exhibit an openwork structure. Such a structure is optimal for SSSC construction because it increases the surface contact area between CH3NH3PbI3 and p-conductor.

  12. Theoretical study on the mechanism of CH3NH2 and O3 atmospheric reaction

    Indian Academy of Sciences (India)

    Samira Valehi; Morteza Vahedpour


    Reaction pathways of methylamine with ozone on the singlet potential energy profile have been investigated at the RB3LYP/6-311++G (3df-3pd) computational level. Calculated results reveal that six kinds of products P1 (CH3NO + H2O2), P2 (CH3NH + OH + O2), P3 (NH2CH + HO2+ OH), P4 (CH2NH + H2O +O2), P5 (NH2CH2OH + O2), P6 (NH3+ CH2O +O2) are obtained through variety of transformation of one reactant complex C1. Cleavage and formation of the chemical bonds in the reaction pathways have been discussed using the structural parameters. Based on the calculations, the title reaction leads to NH3+ CH2O + O2 as thermodynamic adducts in an exothermic process by −76.28 kcal/mol in heat realizing and spontaneous reaction by −86.71 kcal/mol in standard Gibbs free energy. From a kinetic viewpoint, the production of CH3NH + OH + O2 adducts with one transition state is the most favoured path.

  13. Penggunaan zeolit alam untuk mengurangi kandungan krom dan nh4+ dalam air limbah penyamakan kulit

    Directory of Open Access Journals (Sweden)

    Supraptiningsih Supraptiningsih


    Full Text Available Leather tanning waste water contains chemical compounds, such as chromium and NH4+ in high concentration, so if they are thrown away without treatment they will make some problems. The aims of this research is to adsorb the cations in leather tanning waste water i.e chromium and NH4+ used natural zeolite as an adsorbent. Research was done by comparing amount of chromium and NH4+ in effluent waste water treatment unit with amount of chromium and NH4+ after being adsorbed by zeolite in a batch system. The result of this research showed that efficiency difference between using zeolite and waste water treatment unit was significant. The optimal condition to reduce chromium and NH4+ was by using 300 grams per liter waste, zeolite particle size was 50-60 mesh, contact time was 24 hours and pH 8±0,1. In this condition, zeolites could reduce chromium from 3728,56mg/l to 365,39 mg/l or 90,20%, and NH4+ from 3040,02 mg/l menjadi 209,76 mg/l or 93,10%. Waste water treatment unit could reduce chromium 63,55% and NH4+ 56,75%.

  14. Synthesis of tetrapeptide Bz-RGDS-NH2 by a combination of chemical and enzymatic methods. (United States)

    Huang, Yi-Bing; Cai, Yu; Yang, Sen; Wang, Hua; Hou, Rui-Zhen; Xu, Li; Xiao-Xia, Wu; Zhang, Xue-Zhong


    The tetrapeptide Bz-Arg-Gly-Asp-Ser-NH(2) (Bz-RGDS-NH(2)) was successfully synthesized by a combination of chemical and enzymatic methods in this study. Firstly, the precursor tripeptide Gly-Asp-Ser-NH(2) (GDS-NH(2)) was synthesized by a novel chemical method in four steps including chloroacetylation of l-aspartic acid, synthesis of chloroacetyl l-aspartic acid anhydride, the synthesis of ClCH(2)COAsp-SerOMe and ammonolysis of ClCH(2)COAsp-SerOMe. Secondly, lipase (PPL) was used to catalyze the formation of Bz-RGDS-NH(2) in aqueous water-miscible organic cosolvent systems using Bz-Arg-OEt as the acyl donor and GDS-NH(2) as the nucleophile. The optimum conditions were Bz-Arg-OEt 50 mM; GDS-NH(2) 400 mM; 10 degrees C, 0.1M phosphate buffer, pH 7.5; 60% DMF or 58% DMSO, PPL: 10 mg ml(-1) with the maximum yields of the tetrapeptide of 73.6% for DMF and 70.4% for DMSO, respectively. The secondary hydrolysis of the tetrapeptide product did not take place due to the absence of amidase activity of lipase.

  15. First synthesis and structural determination of a monomeric, unsolvated lithium amide, LiNH(2). (United States)

    Grotjahn, D B; Sheridan, P M; Al Jihad, I; Ziurys, L M


    Alkali metal amides typically aggregate in solution and the solid phase, and even in the gas phase. In addition, even in the few known monomeric structures, the coordination number of the alkali metal is raised by binding of Lewis-basic solvent molecules, with concomitant changes in structure. In contrast, the simplest lithium amide LiNH(2) has never been made in a monomeric form, even though its structure has been theoretically predicted several times. Here, the first experimental structural data for a monomeric, unsolvated lithium amide are determined using a combination of gas-phase synthesis and millimeter/submillimeter-wave spectroscopy. All data point to a planar structure for LiNH(2). The r(o) structure of LiNH(2) has a Li-N distance of 1.736(3) A, an N-H distance of 1.022(3) A, and a H-N-H angle of 106.9(1) degrees. These results are compared with theoretical predictions for LiNH(2), and experimental data for oligomeric, solid-phase samples, which could not resolve the question of whether LiNH(2) is planar or not. In addition, comparisons are made with revised gas-phase and solid-phase data and calculated structures of NaNH(2).

  16. Photosynthesis of Quercus suber is affected by atmospheric NH3 generated by multifunctional agrosystems. (United States)

    Pintó-Marijuan, Marta; Da Silva, Anabela Bernardes; Flexas, Jaume; Dias, Teresa; Zarrouk, Olfa; Martins-Loução, Maria Amélia; Chaves, Maria Manuela; Cruz, Cristina


    Montados are evergreen oak woodlands dominated by Quercus species, which are considered to be key to biodiversity conservation and ecosystem services. This ecosystem is often used for cattle breeding in most regions of the Iberian Peninsula, which causes plants to receive extra nitrogen as ammonia (NH(3)) through the atmosphere. The effect of this atmospheric NH(3) (NH(3atm)) on ecosystems is still under discussion. This study aimed to evaluate the effects of an NH(3atm) concentration gradient downwind of a cattle barn in a Montado area. Leaves from the selected Quercus suber L. trees along the gradient showed a clear influence of the NH(3) on δ(13)C, as a consequence of a strong limitation on the photosynthetic machinery by a reduction of both stomatal and mesophyll conductance. A detailed study of the impact of NH(3atm) on the photosynthetic performance of Q. suber trees is presented, and new mechanisms by which NH(3) affects photosynthesis at the leaf level are suggested.

  17. Towards validation of ammonia (NH3 measurements from the IASI satellite

    Directory of Open Access Journals (Sweden)

    M. Van Damme


    Full Text Available Limited availability of ammonia (NH3 observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI satellite has been observing NH3 from space at a high spatiotemporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement but that they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows to investigate the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented.

  18. In Situ Spectroscopic Studies of Proton Transport in Zeolite Catalysts for NH3-SCR

    Directory of Open Access Journals (Sweden)

    Peirong Chen


    Full Text Available Proton transport is an elementary process in the selective catalytic reduction of nitrogen oxides by ammonia (DeNOx by NH3-SCR using metal-exchanged zeolites as catalysts. This review summarizes recent advancements in the study of proton transport in zeolite catalysts using in situ electrical impedance spectroscopy (IS under NH3-SCR reaction conditions. Different factors, such as the metal cation type, metal exchange level, zeolite framework type, or formation of intermediates, were found to influence the proton transport properties of zeolite NH3-SCR catalysts. A combination of IS with diffuse reflection infrared Fourier transformation spectroscopy in situ (in situ IS-DRIFTS allowed to achieve a molecular understanding of the proton transport processes. Several mechanistic aspects, such as the NH3-zeolite interaction, NO-zeolite interaction in the presence of adsorbed NH3, or formation of NH4+ intermediates, have been revealed. These achievements indicate that IS-based in situ methods as complementary tools for conventional techniques (e.g., in situ X-ray absorption spectroscopy are able to provide new perspectives for the understanding of NH3-SCR on zeolite catalysts.

  19. Empirical and mechanistic evaluation of NH4(+) release kinetic in calcareous soils. (United States)

    Ranjbar, F; Jalali, M


    Release, fixation, and distribution of ammonium (NH4(+)) as a source of nitrogen can play an important role in soil fertility and plant nutrition. In this study, ten surface soils, after addition of 1,000 mg NH4(+) kg(-1,) were incubated for 1 week at the field capacity moisture and 25 ± 2 °C temperature, and then NH4(+) release kinetic was investigated by sequential extractions with 10 mM CaCl2. Furthermore, NH4(+) distribution among three fractions, including water-soluble, exchangeable, and non-exchangeable, was determined in all soil samples. NH4(+) release was initially rapid followed by a slower reaction, and this was described well with the Elovich equation as an empirical model. The cumulative NH4(+) concentration released in spiked soil samples had a positive significant correlation with sand content and negative ones with pH, exchangeable Ca(2+)m and K(+), cation exchange capacity (CEC), equivalent calcium carbonate (ECC), and clay content. The cation exchange model in the PHREEQC program was successful in mechanistic simulation of the release trend of native and added NH4(+) in all control and spiked soil samples. The results of fractionation experiments showed that the non-exchangeable fraction in control and spiked soil samples was greater than that in water-soluble and exchangeable fractions. Soil properties, such as pH, exchangeable Ca(2+) and K(+), CEC, ECC, and contents of sand and clay, had significant influences on the distribution of NH4(+) among three measured fractions. This study indicated that both native and recently fixed NH4(+), added to soil through the application of fertilizers, were readily available for plant roots during 1 week after exposure.

  20. An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements (United States)

    Dammers, Enrico; Palm, Mathias; Van Damme, Martin; Vigouroux, Corinne; Smale, Dan; Conway, Stephanie; Toon, Geoffrey C.; Jones, Nicholas; Nussbaumer, Eric; Warneke, Thorsten; Petri, Christof; Clarisse, Lieven; Clerbaux, Cathy; Hermans, Christian; Lutsch, Erik; Strong, Kim; Hannigan, James W.; Nakajima, Hideaki; Morino, Isamu; Herrera, Beatriz; Stremme, Wolfgang; Grutter, Michel; Schaap, Martijn; Wichink Kruit, Roy J.; Notholt, Justus; Coheur, Pierre-F.; Erisman, Jan Willem


    Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs = 547) give a mean relative difference of -32.4 ± (56.3) %, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100 %).

  1. Validation of NH3 satellite observations by ground-based FTIR measurements (United States)

    Dammers, Enrico; Palm, Mathias; Van Damme, Martin; Shephard, Mark; Cady-Pereira, Karen; Capps, Shannon; Clarisse, Lieven; Coheur, Pierre; Erisman, Jan Willem


    Global emissions of reactive nitrogen have been increasing to an unprecedented level due to human activities and are estimated to be a factor four larger than pre-industrial levels. Concentration levels of NOx are declining, but ammonia (NH3) levels are increasing around the globe. While NH3 at its current concentrations poses significant threats to the environment and human health, relatively little is known about the total budget and global distribution. Surface observations are sparse and mainly available for north-western Europe, the United States and China and are limited by the high costs and poor temporal and spatial resolution. Since the lifetime of atmospheric NH3 is short, on the order of hours to a few days, due to efficient deposition and fast conversion to particulate matter, the existing surface measurements are not sufficient to estimate global concentrations. Advanced space-based IR-sounders such as the Tropospheric Emission Spectrometer (TES), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) enable global observations of atmospheric NH3 that help overcome some of the limitations of surface observations. However, the satellite NH3 retrievals are complex requiring extensive validation. Presently there have only been a few dedicated satellite NH3 validation campaigns performed with limited spatial, vertical or temporal coverage. Recently a retrieval methodology was developed for ground-based Fourier Transform Infrared Spectroscopy (FTIR) instruments to obtain vertical concentration profiles of NH3. Here we show the applicability of retrieved columns from nine globally distributed stations with a range of NH3 pollution levels to validate satellite NH3 products.

  2. CN, NH2, and dust in the atmosphere of comet C/1999 J3 (LINEAR) (United States)

    Korsun, P. P.; Jockers, K.


    Comet C/1999 J3 (LINEAR) was observed with 2 m telescope of the Pik Terskol Observatory on September 19, 1999. Narrow-band CCD images of the CN, NH2, and dust atmospheres were recorded with the Two-Channel focal reducer of the Max-Plank-Institute for Aeronomy. The distributions of the CN and NH2 molecules in the comet atmosphere were fitted with a Monte Carlo model. For the CN atmosphere the best agreement between observed and calculated surface profiles was reached with the CN photodissociation lifetime tau (CN)=1.5*E5 s and with the parent photodissociation lifetime tau (CNparent)=3.2*E4 s. This result indicates that HCN is the main source of the CN radicals in the atmosphere of comet C/1999 J3 (LINEAR). Regarding the NH2 radicals, there is no doubt that NH3 is the dominant source of this species in the comet atmosphere. The lifetimes tau (NH2)=1.0*E5 s for NH2 and tau (NH2 parent)=5.0*E3 s for its parent are close to theoretical calculations. The gas-production rates of CN, Q(CN)=3.8 *E25 mol s-1, and NH2, Q(NH2)=6.9*E25 mol s-1 have also been determined. The appearance of the comet and the obtained data show that the comet is a gaseous one. The Afrho values are 21.6 cm for the blue spectral window and 23.4 cm for the red one. The normalized spectral gradient of the cometary dust is low, 4.0% per 1000 Å. The ratio log((Afrho )443/Q(CN)) = -24.25 indicates a very low dust to gas ratio as well.

  3. Evaluation study of the suitability of instrumentation to measure ambient NH3 concentrations under field conditions (United States)

    Twigg, Marsailidh


    The uncertainties in emissions of ammonia (NH3) in Europe are large, partially due to the difficulty in monitoring of ambient concentrations due to its sticky nature. In the European Monitoring and Evaluation Program (EMEP) the current recommended guidelines to measure NH3 are by coated annular denuders with offline analysis. This method, however, is no longer used in most European countries and each one has taken a different strategy to monitor atmospheric ammonia due to the increase of commercial NH3 monitoring instrumentation available over the last 20 years. In June 2014, a 3 year project funded under the European Metrology Research Programme, "Metrology for Ammonia in Ambient Air" (MetNH3), started with the aim to develop metrological traceability for the measurement of NH3 in air from primary gas mixtures and instrumental standards to field application. This study presents the results from the field intercomparison (15 instruments) which was held in South East Scotland in August 2016 over an intensively managed grassland. The study compared active sampling methods to a meteorological traceable method which was developed during the project with the aim to produce a series of guidelines for ambient NH3 measurements. Preliminary results highlight both the importance of inlets and management of relative humidity in the measurement of ambient NH3 and of the requirement to carry out frequent intercomparison of NH3 instrumentation. Overall, it would be recommended from this study that a WMO-GAW world centre for NH3 would be established and support integration of standards into both routine and research measurements.

  4. Study of various NH4+/NO3- mixtures for enhancing growth of potatoes (United States)

    Cao, W.; Tibbitts, T. W.


    Two experiments were conducted to determine the effects of various NH4(+)-N/NO3(-)-N percentages on growth and mineral concentrations in potato (Solanum tuberosum L.) plants using a non-recirculating nutrient film system in a controlled environment. The first experiment included six NH4(+)-N/NO3(-)-N percentages at 0/100, 20/80, 40/60, 60/40, 80/20, and 100/0 with the same total N concentration of 4 mM. The second experiment included six NH4(+)-N/NO3(-)-N percentages at 0/100, 4/96, 8/92, 12/88, 16/84, and 20/80 again with the same total N of 4 mM. In each experiment, plants were harvested 35 days after transplanting when tubers had been initiated and started to enlarge. Dry weights of shoots, tubers, and whole plant at the harvest were increased significantly with all mixed nitrogen treatments as compared with single NH4+ or NO3- form. The enhanced growth with mixed nitrogen was greatest at 8% to 20% NH4(+)-N. Also, the concentrations and accumulation of total N in the shoots and roots were greater with mixed nitrogen than with separate NH4+ or NO3- nutrition. With NH4+ present in the solutions, the concentrations of P and Cl in the shoots were increased compared to NO3- alone, whereas the tissue concentrations of Ca and Mg were decreased. It was concluded that nitrogen fertilization provided with combined NH4+ and NO3- forms, even at small proportions of NH4+, can enhance nitrogen uptake and productivity in potato plants.

  5. Synthesis and Characterization of Layered Perovskite-type Organic-inorganic Hybrids (R-NH3)2(CH3NH3)Pb2I7

    Institute of Scientific and Technical Information of China (English)

    GUO Liling; SUN Zhang; ZHAO Guanghui; LI Xing; LIU Hanxing


    Layered organic-inorgamc hybrids containing bilayer perovsikte (R-NH3)2(CH3NH3)Pb2I7(where R=C12H25,C6H5C2H4) were synthesized by reactions in solution.The influences of the solvents and the reactant ratio on the structures of the products were investigated.The structures and the properties of the hybrids were characterized using X-ray diffraction (XRD) and ultraviolet and visible (UV) adsorption spectra.For comparing with the bilayer perovskite hybrids in structure and band gap magnitude,the hybrids containing monolayer perovskite (R-NH3)2PbI4 were also synthesized and characterized.The results demonstrate that the thickness of inorganic layer has obvious effect on the tunneling magnitude of the band gap but the organic part can be micro actuator of band gap.

  6. First in-situ detection of the cometary ammonium ion NH_4+ (protonated ammonia NH3) in the coma of 67P/C-G near perihelion (United States)

    Beth, A.; Altwegg, K.; Balsiger, H.; Berthelier, J.-J.; Calmonte, U.; Combi, M. R.; De Keyser, J.; Dhooghe, F.; Fiethe, B.; Fuselier, S. A.; Galand, M.; Gasc, S.; Gombosi, T. I.; Hansen, K. C.; Hässig, M.; Héritier, K. L.; Kopp, E.; Le Roy, L.; Mandt, K. E.; Peroy, S.; Rubin, M.; Sémon, T.; Tzou, C.-Y.; Vigren, E.


    In this paper, we report the first in-situ detection of the ammonium ion NH_4+ at 67P/Churyumov-Gerasimenko (67P/C-G) in a cometary coma, using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) / Double Focusing Mass Spectrometer (DFMS). Unlike neutral and ion spectrometers onboard previous cometary missions, the ROSINA/DFMS spectrometer, when operated in ion mode, offers the capability to distinguish NH_4+ from H2O+ in a cometary coma. We present here the ion data analysis of mass-to-charge ratios 18 and 19 at high spectral resolution and compare the results with an ionospheric model to put the these results into context. The model confirms that the ammonium ion NH_4+ is one of the most abundant ion species, as predicted, in the coma near perihelion.

  7. The electronic structure of organic-inorganic hybrid compounds : (NH4)(2)CuCl4, (CH3NH3)(2)CuCl4 and (C2H5NH3)(2)CuCl4

    NARCIS (Netherlands)

    Zolfaghari, P.; de Wijs, G. A.; de Groot, R. A.


    Hybrid organic-inorganic compounds are an intriguing class of materials that have been experimentally studied over the past few years because of a potential broad range of applications. The electronic and magnetic properties of three organic-inorganic hybrid compounds with compositions (NH4)(2)CuCl4

  8. The international research progress of Ammonia(NH3) emissions and emissions reduction technology in farmland ecosystem (United States)

    Yang, W. Z.; Jiao, Y.


    NH3 is the important factor leading to the grey haze, and one of the main causes of environmental problems of serious ecological imbalance, such as acid rain and air quality deterioration. The fertilizer excessive application of the current farmland results NH3 emissions intensity greatly. In order to clear the farmland NH3 emissions research status and achievements, the literature of farmland NH3 emission related were retrievaled by the SCI journals and Chinese science citation database. Some factors of NH3 emission were analyzed such as soil factors, climate factors and farmland management measures. The research progress was inductived on farmland NH3 emission reduction technology. The results will help to clarify farmland NH3 emissions research progress. The theoretical guidance was provided on the future of farmland NH3 emissions research.

  9. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem modelecosystem model (United States)

    Atmospheric ammonia (NH3) is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurement...

  10. Messung der Geschwindigkeitskonstanten der Reaktion NH2+CH4→NH3+CH3 hinter einfallenden Stoßwellen / Measurements of the Rate Constant of the Reaction NH2+CH4→NH3+CH3 behind Incident Shock Waves (United States)

    Möller, W.; Wagner, H. Gg.


    The rate constant of the reaction NH2+CH4→NH3+CH3 was measured at temperatures of about 1800 K by time-resolved UV-spectroscopy of the products behind incident shock waves. NH2 was produced by the presence and thermal decomposition of hydrazine. The data were evaluated by fitting simulated concentration-time-profiles to the measured ones. A mean rate constant k = (4±2) 1011 cm3 mol-1 s-1 1730

  11. The mechanism of the NH4 ion oscillatory transport across the excitable cell membrane

    Directory of Open Access Journals (Sweden)

    Radenović Čedomir N.


    Full Text Available This paper presents results on typical oscillations of the membrane potential induced by the excitation of the cell membrane by different concentrations of the NH4Cl solution. The existence of four classes of oscillations of the membrane potential and several different single and local impulses rhythmically occurring were determined. It is known that the oscillatory processes of the membrane potential are in direct dependence on oscillatory transport processes of NH4 and Cl ions across the excitable cell membrane. A hypothesis on a possible mechanism of oscillatory transport processes of NH4 and Cl ions across the excitable cell membrane is also presented.

  12. Theoretical Study of Electron Transfer in Bimolecular System of NH3 and H2O

    Institute of Scientific and Technical Information of China (English)


    Mulliken, NPA, MK and CHelpG population analyses have been accomplished at the level of MP2/6-31G(d,p) for the title system. The variations of four kinds of charges on NH3 with intermolecular distance infer that electron transfers from NH3 to H2O. MK and CHelpG population analyses indicate more electron transfer than Mulliken and NPA ones. The atomic charges resulted from MK and CHelpG schemes infer that electron transfers from N in NH3 to H in H2O, which confirms that this bimolecular complex possesses linear structure as H3N…HOH.

  13. Effects of atmospheric ammonia (NH3) on terrestrial vegetation: a review. (United States)

    Krupa, S V


    At the global scale, among all N (nitrogen) species in the atmosphere and their deposition on to terrestrial vegetation and other receptors, NH3 (ammonia) is considered to be the foremost. The major sources for atmospheric NH3 are agricultural activities and animal feedlot operations, followed by biomass burning (including forest fires) and to a lesser extent fossil fuel combustion. Close to its sources, acute exposures to NH3 can result in visible foliar injury on vegetation. NH3 is deposited rapidly within the first 4-5 km from its source. However, NH3 is also converted in the atmosphere to fine particle NH4+ (ammonium) aerosols that are a regional scale problem. Much of our current knowledge of the effects of NH3 on higher plants is predominantly derived from studies conducted in Europe. Adverse effects on vegetation occur when the rate of foliar uptake of NH3 is greater than the rate and capacity for in vivo detoxification by the plants. Most to least sensitive plant species to NH3 are native vegetation > forests > agricultural crops. There are also a number of studies on N deposition and lichens, mosses and green algae. Direct cause and effect relationships in most of those cases (exceptions being those locations very close to point sources) are confounded by other environmental factors, particularly changes in the ambient SO2 (sulfur dioxide) concentrations. In addition to direct foliar injury, adverse effects of NH3 on higher plants include alterations in: growth and productivity, tissue content of nutrients and toxic elements, drought and frost tolerance, responses to insect pests and disease causing microorganisms (pathogens), development of beneficial root symbiotic or mycorrhizal associations and inter species competition or biodiversity. In all these cases, the joint effects of NH3 with other air pollutants such as all-pervasive O3 or increasing CO2 concentrations are poorly understood. While NH3 uptake in higher plants occurs through the shoots, NH4

  14. Rabbit pulmonary angiotensin-converting enzyme: the NH2-terminal fragment with enzymatic activity and its formation from the native enzyme by NH4OH treatment. (United States)

    Iwata, K; Blacher, R; Soffer, R L; Lai, C Y


    The NH2-terminal sequence of 22 residues of rabbit lung angiotensin-converting enzyme has been determined as (NH2)Thr-Leu-Asp-Pro-Gly-Leu-Leu-Pro-Gly-Asp-Phe-Ala -Ala-Asp-Asn-Ala-Gly-Ala-Arg-Leu-Phe-Ala-. In the course of purification of the enzyme for structural analysis a protein of Mr = 82,000 with angiotensin-converting activity was separated from the major fraction containing the native enzyme (Mr = 140,000). This low-molecular-weight enzyme catalyzed the hydrolysis of the synthetic substrate Hip-His-Leu at a rate 23% of that with the native enzyme, and exhibited a similar Km value as well as behaviors towards various effectors of angiotensin-converting enzyme. Edman degradation of both the native and the 82K enzymes revealed that they contain identical amino acid sequences from the NH2-termini. This result and those of peptide mapping and carbohydrate and amino acid analyses indicate that the 82K enzyme is a fragment derived from the NH2-terminal portion of the native enzyme, and hence contains its catalytic site. Evidence has been obtained indicating that the active fragment was formed from the native enzyme during its elution from the antibody-affinity column with NH4OH: on treatment of the native enzyme (140K Mr) with 1 N NH4OH at room temperature, a cleavage occurred and two proteins with Mr = 82K and Mr = 62K were obtained. The 82K Mr fragment was found to be enzymatically active and to contain the same NH2-terminal sequence as the native enzyme. The other fragment (62K Mr) was devoid of the activity and was shown to derive from the COOH-terminal portion of the native enzyme by the peptide mapping and terminal analyses. Cleavage of a peptide bond with NH4OH is unusual and appears to be specific for the native angiotensin-converting enzyme from rabbit lung.

  15. Anodic reaction kinetics of electrowinning zinc in system of Zn(Ⅱ)-NH3-NH4Cl-H2O

    Institute of Scientific and Technical Information of China (English)

    杨声海; 唐谟堂; 陈艺锋; 唐朝波; 何静


    The anodic reaction kinetics of zinc electrowinning was investigated on the titanium base RuO2 anode in the system of Zn(Ⅱ)-NH3-NH4Cl-H2O. The effects of stirring speed, ammonium chloride concentration and temperature on anodic reaction rate were studied through the curve measurement of potentiostatic polarization. The results reveal that the electrochemically controlled anodic reaction obeys Tafel equation and the anodic reaction order for ammonium chloride is 1. 056, with the apparent activation energy of 40.17 kJ/mol. The general equation of anodic reaction kinetics was obtained.

  16. Structure-function studies of BPP-BrachyNH2 and synthetic analogues thereof with Angiotensin I-Converting Enzyme

    DEFF Research Database (Denmark)

    Arcanjo, Daniel Dias Rufino; Vasconcelos, Andreanne Gomes; Nascimento, Lucas A


    The vasoactive proline-rich oligopeptide termed BPP-BrachyNH2 (H-WPPPKVSP-NH2) induces in vitro inhibitory activity of angiotensin I-converting enzyme (ACE) in rat blood serum. In the present study, the removal of N-terminal tryptophan or C-terminal proline from BPP-BrachyNH2 was investigated in ...

  17. Estimation of global NH3 emissions from synthetic fertilizers and animal manure applied to arable lands and grasslands

    NARCIS (Netherlands)

    Bouwman, A.F.; Boumans, L.J.M.; Batjes, N.H.


    One of the main causes of the low efficiency in nitrogen (N) use by crops is the volatilization of ammonia (NH3) from fertilizers. Information taken from 1667 NH3 volatilization measurements documented in 148 research papers was summarized to assess the influence on NH3 volatilization of crop type,

  18. Evaluating 4 years of atmospheric ammonia (NH3) over Europe using IASI satellite observations and LOTOS-EUROS model results

    NARCIS (Netherlands)

    Damme, M. van; Wichink Kruit, R.J.; Schaap, M.; Clarisse, L.; Clerbaux, C.; Coheur, P.F.; Dammers, E.; Dolman, A.J.; Erisman, J.W.


    Monitoring ammonia (NH3) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH3 distributions generally relies on model calculations. Novel remotely sensed NH3burdens provide valuable insights to co

  19. GLOBEC NEP Northern California Current Cetacean Survey Data, NH0005, 0007 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) Northern California Current Cetacean Survey Data from R/V New Horizon cruises NH0005 and 0007....

  20. Plasma chemistry in an atmospheric pressure Ar/NH3 dielectric barrier discharge

    DEFF Research Database (Denmark)

    Fateev, A.; Leipold, F.; Kusano, Y.


    An atmospheric pressure dielectric barrier discharge (DBD) in Ar/NH3 (0.1 - 10%) mixtures with a parallel plate electrode geometry was studied. The plasma was investigated by emission and absorption spectroscopy in the UV spectral range. Discharge current and voltage were measured as well. UV...... absorption spectroscopy was also employed for the detection of stable products in the exhaust gas. To clarify the different processes for ammonia decomposition, N-2(2 - 10%) was added to the plasma. Modeling of the chemical kinetics in an Ar/NH3 plasma was performed as well. The dominant stable products...... of an atmospheric pressure Ar/NH3 DBD are H-2, N-2 and N2H4. The hydrazine (N2H4) concentration in the plasma and in the exhaust gases at various ammonia concentrations and different discharge powers was measured. Thermal N2H4 decomposition into NH2 radicals may be used for NOx reduction processes....

  1. Phosphine-free conversion of alcohols into alkyl thiocyanates using trichloroisocyanuric acid/NH4SCN

    Institute of Scientific and Technical Information of China (English)

    Roya Azadi; Babak Mokhtari; Mohamad-Ali Makaremi


    A convenient and efficient phosphine-free procedure for the one-pot conversion of primary,secondary and tertiary alcohols into the corresponding alkyl thiocyanates or alkyl isothiocyanates is described using trichloroisocyanuric acid/NH4SCN.

  2. NOAA Climate Data Record (CDR) of Northern Hemisphere (NH) Snow Cover Extent (SCE), Version 1 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) is a record for the Northern Hemisphere (NH) Snow Cover Extent (SCE) spanning from October 4, 1966 to present, updated monthly...

  3. Review of ASME-NH Design Materials for Creep-Fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Gyeong Hoi; Kim, Jong Bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    To review and recommend the candidate design materials for the Sodium-Cooled Fast Reactor, the material sensitivity evaluations by the comparison of design data between the ASME-NH materials were performed by using the SIE ASME-NH computer program implementing the material database of the ASME-NH. The design material data provided by the ASME-NH code are the elastic modulus and yield Strength, Time-Independent Allowable Stress Intensity value, time-dependent allowable stress intensity value, expected minimum stress-to rupture value, stress rupture Factors for weldment, isochronous stress-strain curves, and design fatigue curves. Among these, the data related with the creep-fatigue evaluation are investigated in this study

  4. Structure and Stability of Endohedral Complexes X@(HAlNH)12 (X = He, Ne, Ar, Kr)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cai-Yun; WU Hai-Shun


    The structures of closo-hedral cluster (HAlNH)12 and endohedral complexes X@(HAlNH)12 (X = He, Ne, Ar, Kr) have been studied by using density functional theory (DFT) at the B3LYP/6-31G(d) level. The geometries, natural bond orbital (NBO), vibrational frequency, energetic parameters, magnetic shielding constants and nucleus independent chemical shifts (NICS) were discussed. The potential surface of guest X shifting from the cage center to a face of six- membered ring was calculated at the same level. The exit transition state was demonstrated with IRC calculations. It is found that X@(HAlNH)12 complexes are dynamically stable, and Ne@(HAlNH)12 is more energetically favorable than the other complexes in thermodynamics.

  5. Stratified NH and ND emission in the prestellar core 16293E in L1689N

    CERN Document Server

    Bacmann, A; Caselli, P; Ceccarelli, C; Lis, D; Vastel, C; Dumouchel, F; Lique, F; Caux, E


    High degrees of deuterium fractionation are commonly found in cold prestellar cores and in the envelopes around young protostars. As it brings strong constraints to chemical models, deuterium chemistry is often used to infer core history or molecule formation pathways. Whereas a large number of observations is available regarding interstellar deuterated stable molecules, relatively little is known about the deuteration of hydride radicals, as their fundamental rotational transitions are at high frequencies where the atmosphere is mostly opaque. Nitrogen hydride radicals are important species in nitrogen chemistry, as they are thought to be related to ammonia formation. Observations have shown that ammonia is strongly deuterated, with [NH2D]/[NH3] ~ 10%. Models predict similarly high [ND]/[NH] ratios, but so far only one observational determination of this ratio is available, towards the envelope of the protostar IRAS16293-2422. In order to test model predictions, we aim here at determining [ND]/[NH] in a dens...

  6. Is electronegativity a useful descriptor for the pseudo-alkali metal NH4? (United States)

    Whiteside, Alexander; Xantheas, Sotiris S; Gutowski, Maciej


    Molecular ions in the form of "pseudo-atoms" are common structural motifs in chemistry, with properties that are transferrable between different compounds. We have determined one such property--the electronegativity--for the "pseudo-alkali metal" ammonium (NH(4)), and evaluated its reliability as a descriptor versus the electronegativities of the alkali metals. The computed properties of ammonium's binary complexes with astatine and of selected borohydrides confirm the similarity of NH(4) to the alkali metal atoms, although the electronegativity of NH(4) is relatively large in comparison to its cationic radius. We have paid particular attention to the molecular properties of ammonium (angular anisotropy, geometric relaxation and reactivity), which can cause deviations from the behaviour expected of a conceptual "true alkali metal" with this electronegativity. These deviations allow for the discrimination of effects associated with the molecular nature of NH(4).

  7. Use of NH3 fuel to achieve deep greenhouse gas reductions from US transportation

    Directory of Open Access Journals (Sweden)

    Doo Won Kang


    The current study demonstrates that NH3-fueled vehicles could be a promising near-term alternative for LDV because of its significant contribution in reducing CO2 emissions compared with vehicles of carbon based fuels.

  8. A study of the adsorption of NH 3 and SO 2 on leaf surfaces (United States)

    Van Hove, L. W. A.; Adema, E. H.; Vredenberg, W. J.; Pieters, G. A.

    The adsorption of NH 3 and SO 2 on the external leaf surface of bean ( Phaseolus vulgaris L.) and poplar ( Populus euramericana L.) was studied. The adsorbed quantities increased strongly with increasing air humidity, indicating that water on the leaf surface plays a major role in the interaction of these gases with the leaf surface. On the other hand temperature in the range between 15 and 26°C had no significant influence. The adsorbed quantities of NH 3 at a specific air humidity appeared to be proportional to NH 3 concentration. This proportionality was less clear for SO 2. The affinity of SO 2 for the leaf surface was found to be approximately twice that of NH 3. A mixture of these gases in the air mutually stimulated their adsorption on the leaf. No significant desorption or uptake of these gases through the cuticle could be detected, indicating that the bulk of the adsorbed gases remains associated with the cuticle.

  9. Crystal structure and characterization of the novel NH{sup +} Midline-Horizontal-Ellipsis N hydrogen bonded polar crystal [NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Wojtas, M., E-mail: [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Gagor, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Science, PO Box 1410, 50-950 Wroclaw (Poland); Czupinski, O. [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Medycki, W. [Institute of Molecular Physics, Polish Academy of Science, Smoluchowskiego 17, 60-179 Poznan (Poland); Jakubas, R. [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland)


    Dielectric properties and phase transitions of the piperazinium tetrafluoroborate ([NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}], abbreviated as PFB) crystal are related to the one-dimensional arrangement of the cations linked by the bistable NH{sup +} Midline-Horizontal-Ellipsis N hydrogen bonds and molecular motions of the [BF{sub 4}]{sup -} units. The crystal structure of [NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}] is monoclinic at room temperature with the polar space group Pn. The polar/acentric properties of the room temperature phase IV have been confirmed by the piezoelectric and pyroelectric measurements. DSC measurements show that the compound undergoes three first-order structural phase transitions: at 421/411 K (heating/cooling), at 386/372 K and at 364/349 K. {sup 1}H and {sup 19}F NMR measurements indicate the reorientational motions of [BF{sub 4}]{sup -} anions and piperazinium(+) cations as well as the proton motion in the hydrogen-bonded chains of piperazine along the [001] direction. Over the phase I the isotropic reorientational motions or even self-diffusion of the cations and anions are expected. The conductivity measurements in the vicinity of the II-I PT indicate a superionic phase over the phase I. - Graphical abstract: It must be emphasized that the titled compound represents the first organic-inorganic simple salt containing the single-protonated piperazinium cation which was studied by means of the wide variety of experimental techniques. A survey of Cambridge Structural Database (CSD version 5.32 (November 2010) and updates (May 2011)) for structure containing the piperazinium cations yields 248 compounds with the doubly protonated piperazinium(2+) cations and only eight compounds with the singly protonated piperazinium(+) cations. Among these structures only one is the hybrid organic-inorganic material. This is piperazinium nitrate characterized structurally. The crystal packing of [NH{sub 2}(CH{sub 2}){sub 4}NH][BF{sub 4}], phase IV. The

  10. The Galactic NH - AV Relation and its Application to Historical Galactic SNRs

    CERN Document Server

    Tian, Wen-Wu; Xiang, F Y


    We refine a classic relation between the hydrogen column density (NH) and optical extinction (Av) by employing 39 Galactic Supernova Remnants (SNRs) with X-rays, optical and/or infra-red data available. We find NH = (1.69+/-0.07)*10^21 Av cm^(-2) mag^(-1) . Applying this relation to three Galactic SNRs with good historical records allows us to further constrain either their progenitor's distances or magnitudes, which is independent access to their distances.

  11. Porphyrin molecules boost the sensitivity of epitaxial graphene for NH3 detection (United States)

    Iezhokin, I.; den Boer, D.; Offermans, P.; Ridene, M.; Elemans, J. A. A. W.; Adriaans, G. P.; Flipse, C. F. J.


    The sensitivity of quasi-free standing epitaxial graphene for NH3 detection is strongly enhanced by chemical functionalization with cobalt porphyrins resulting in a detection limit well below 100 ppb. Hybridization between NH3 and cobalt porphyrins induces a charge transfer to graphene and results in a shift of the graphene Fermi-level as detected by Hall measurements and theoretically explained by electronic structure calculations.

  12. Effects of high NH4+ on K+ uptake, culm mechanical strength and grain filling in wheat

    Directory of Open Access Journals (Sweden)

    Lingan eKong


    Full Text Available It is well established that a high external NH4+ concentration depresses many processes in plant development, but the underlying mechanisms are still not well understood. To determine whether the negative effects of high levels of NH4+ are related to competitive cation uptake, wheat was grown in a field with moderate (18 g N m-2 and high (30 g N m-2 supplies of NH4+ in the presence or absence of additional K+ (6 g K2O m-2 to examine culm mechanical strength, the main components of the vascular bundle, nitrogen (N remobilization and the grain-filling rate. The results indicated that an excessive supply of NH4+ significantly decreased culm mechanical strength, the cellulose and lignin contents of vascular bundles, the N remobilization efficiency (NRE and the grain-filling rate compared with a moderate level of NH4+. The additional provision of K+ considerably alleviated these negative effects of high NH4+, resulting in a 19.41%-26.95% increase in culm mechanical strength during grain filling and a 34.59% increase in the NRE. An assay using the scanning ion-selective electrode technique (SIET showed that the net rate of transmembrane K+ influx decreased by 84.62%, and measurements using flame photometry demonstrated that the K+ content decreased by 36.13% in wheat plants subjected to high NH4+. This study indicates that the effects of high NH4+ on culm mechanical strength, cellulose and lignin contents, the NRE and the grain-filling rate are probably associated with inhibition of K+ uptake in wheat.

  13. NH+4型斜发沸石吸附钾离子%Adsorption of Potassium on NH+4-pretreated Clinoptilolite

    Institute of Scientific and Technical Information of China (English)

    程国斌; 韩梅; 王刃; 马伟


    研究了NH+4型斜发沸石对盐水中钾离子的吸附行为,考察了竞争阳离子等对铵型斜发沸石吸附钾离子的影响. 结果表明,NH+4型斜发沸石对钾离子具有较强的选择吸附性与较大的饱和吸附容量,受钾离子初始浓度的影响,NH+4型斜发沸石吸附钾离子的行为在沸石相K+平衡分数YK+为0.5时发生较大转折. 竞争阳离子的存在在不同程度上抑制了铵型斜发沸石对钾离子的吸附,特别是钾离子与钠离子的相对比例直接影响NH+4型斜发沸石对混合液中钾离子的选择交换能力.

  14. The fate of 15NH4 + labeled deposition in a Scots pine forest in the Netherlands under high and lowered NH4+ deposition, eight years after application

    NARCIS (Netherlands)

    Wessel, W.W.; Tietema, A.; Boxman, A.W.


    To study the long-term fate of deposited ammonium (NH4 +) in a Scots pine forest stand under high nitrogen (N) deposition in the Netherlands we re-sampled the plots of a 15N tracer experiment with high (i.e. ambient) and lowered N deposition in this stand 8 years after application of the tracer. The

  15. NASICON固体电解质NH3传感器的研制%NH3 Gas Sensor based on NASICON Solid-electrolyte

    Institute of Scientific and Technical Information of China (English)

    梁喜双; 钟铁钢; 刘凤敏; 全宝富


    本文介绍了一种管式结构的固体电解质NH,传感器.该传感器是将溶胶-凝胶法制备的NASICON为导电层材料,以掺杂C的Cr2O3为辅助电极材料制得的.当工作温度在250~450℃时,器件对浓度为(50-500)x10-6的NH3表现出了良好的气敏性能,器件电动势EMF值与NH3浓度的对数表现出了很好的线性关系,在350℃时,器件的灵敏度为89 mV/decade.同时,器件表现出较快的响应恢复速度,对50×10-6的NH3的响应恢复时间分别为30s和60s,且有较好的选择性.

  16. Effect on the morphology and optical properties of CH3NH3PbI3 with additive of NH4Cl (United States)

    Yan, Xiaoliang; Yang, Xiao; Wang, Ruizhi; Li, Heng; Sheng, Chuanxiang


    Rapid emergence of solar cells based on mixed organic-inorganic halide perovskite have led to high power conversion efficiencies of over 20% in recent years. Looking for a simple and convenient way to fine-control of the perovskite film morphology is becoming one of the main issues. In this work, we explore the effect of adding NH4Cl on crystallization process and optical properties of perovskite. With adding NH4Cl, the perovskite films prepared by one-step method present better morphology than films without adding NH4Cl, namely, smoother surface and better coverage which result in uniform and much more stable photoluminescence intensities as well as longer lifetime of photoexcitations. More importantly, the photovoltaic cells fabricated with the addition of the NH4Cl have far better performance than the cells without additives. Therefore, one-step fabrication method can also control the morphology of perovskite films finely for both optical application and solar cells with adding proper additive.

  17. Molecular observations of HH34 - Does NH3 accurately trace dense molecular gas near young stars? (United States)

    Davis, C. J.; Dent, W. R. F.


    Single-dish observations in HCO(+) J = 4-3 are presented of the regions around HH34 and around HH34IRS. The former is one of the best examples of the association between Herbig-Haro shocks, optical jets, and young stellar objects. The HCO(+) and CS maps peak toward the outflow source HH34IRS and suggest the presence of a hot dense molecular core. The NH3 is confined to a peak about 4-0 arcsec east of HH34IRS and to a ridge which extends in a north-south direction and peaks about 20 arcsec south of the end of the optical jet. Thus, the NH3 observations do not trace the underlying gas density and temperature in this outflow source. Toward HH34IRS the NH3 column density is less by a factor of about 10 than toward the NH3 peak position is the HH34 region, providing evidence that the NH3 is underabundant towards the central exciting stars. This underabundance may explain the toroidal structures often seen in NH3 observations of other outflow sources.

  18. [Contents of nutrient elements in NH4(+)-N fertilizer and urea]. (United States)

    Wang, Zheng-Rui; Qu, Gui-Qin; Rui, Yu-Kui; Shen, Jian-Bo; Zhang, Fu-Suo


    Fertilizer contains not only one compound or one element, so it is important to determine the contents of other elements necessitous and beneficial to plant. All the other nutrient elements for plant, including necessitous elements and beneficial elements in ammonia nitrogen fertilizer ((NH4)2SO4) and CO(NH2)2, were analyzed by method of ICP-MS. The results showed that ammonia nitrogen fertilizer ((NH4)2SO4) and CO(NH2)2 both contain many necessitous elements, Mg, P, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo, thereinto the contents of Mg, P, K, Ca, Mn and Fe were on microg x g(-1) the level, and Ni, Cu, Zn and Mo were on the ng x g(-1) level; compared with CO(NH2)2, ammonia nitrogen fertilizer ((NH4)2SO4) contains more necessitous elements and beneficial elements except Mo and Si. All the above elements could influence the results of nitrogen fertilizer efficiency experiments, so pure fertilizer should be used in the future nitrogen fertilizer efficiency experiments and the comparative experiments of different form nitrogen fertilizer.

  19. [Effects of superphosphate addition on NH3 and greenhouse gas emissions during vegetable waste composting]. (United States)

    Yang, Yan; Sun, Qin-ping; Li, Ni; Liu, Chun-sheng; Li, Ji-jin; Liu, Ben-sheng; Zou, Guo-yuan


    To study the effects of superphosphate (SP) on the NH, and greenhouse gas emissions, vegetable waste composting was performed for 27 days using 6 different treatments. In addition to the controls, five vegetable waste mixtures (0.77 m3 each) were treated with different amounts of the SP additive, namely, 5%, 10%, 15%, 20% and 25%. The ammonia volatilization loss and greenhouse gas emissions were measured during composting. Results indicated that the SP additive significantly decreased the ammonia volatilization and greenhouse gas emissions during vegetable waste composting. The additive reduced the total NH3 emission by 4.0% to 16.7%. The total greenhouse gas emissions (CO2-eq) of all treatments with SP additives were decreased by 10.2% to 20.8%, as compared with the controls. The NH3 emission during vegetable waste composting had the highest contribution to the greenhouse effect caused by the four different gases. The amount of NH3 (CO2-eq) from each treatment ranged from 59.90 kg . t-1 to 81.58 kg . t-1; NH3(CO2-eq) accounted for 69% to 77% of the total emissions from the four gases. Therefore, SP is a cost-effective phosphorus-based fertilizer that can be used as an additive during vegetable waste composting to reduce the NH3 and greenhouse gas emissions as well as to improve the value of compost as a fertilizer.

  20. NH4+ adsorption and adsorption kinetics by sediments in a drinking water reservoir

    Directory of Open Access Journals (Sweden)

    Suna Hongyan


    Full Text Available The sorption isotherm and sorption kinetics of NH4+ by the Fen River reservoir sediment were investigated for a better understanding of the NH4+ sorption characteristics and parameters. The results showed that Q (adsorption content increased with the increase of Ceq (equilibrium concentration, sorption isotherms could be described by Freundlich equation (R2 from 0.97 to 0.99. Cation exchange capacity (CEC had a significant correlation with the parameters K and n (R2 was 0.85 and 0.95, respectively. The ENC0 (Ceq as Q was zero of S1, S2, S3 and S4 was 1.25, 0.57, 1.15 and 1.14 mg L-1, respectively, and they were less than the NH4+ concentrations in reservoir water. The sediments released NH4+ to the Fen River reservoir water and acted as a pollution source, in the form of complex and heterogeneous adsorbents. The NH4+ adsorption kinetic process was composed of ‘fast’ and ‘slow’ reaction patterns and could be fitted using both Elovich equation and Pseudo second-equation. More than one-step may be involved in the NH4+ sorption processes, and interior diffusion was not dominant ion action.

  1. Thermodynamic Properties of NH4+ Fixation in Manured Loess Soil in Shaanxi Province,China

    Institute of Scientific and Technical Information of China (English)



    Some thermodynamic properties of NH4+ fixation by loess soil in plowing and clay layers are discussed.The results indicate that the four ion adsorption equations commonly used can describe the properties of NH4+ fixation in these soils under constant temperature.Among the four adsorption equations,the single-surface Langmuir equation is the best.When the concentration of NH4Cl solution is 10-1 mol below,the Freundlich equation can be used. The changes of apparent standard free energy(△G°),enthalpy(△H°)and entropy(△S°)ilustrate that NH4+ fixation in soil is an endothermic adsorption and spontaneous reaction,and the process can be enhanced by a higher temperature and clay content in soil. The"proper value of NH4+ fixation by soil(K1×qm)imcreased with increasing clay content and temper-ature.The heat of NH4+ fixation in soil(Qm) confirms the conclusions made in this paper.

  2. Measurement of ambient NH{sub 3} over Bay of Bengal during WICARB Campaign

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, S.K.; Mandal, T.K.; Saxena, M.; Singh, S. [CSIR-National Physical Laboratory, New Delhi (India); Singh, A.K.; Ghosh, S.K.; Raha, S. [Centre for Astroparticle Physics and Space Science, Darjeeling, West Bengal (India). Bose Inst.; Centre for Astroparticle Physics and Space Science, Kolkata, West Bengal (India). Bose Inst.; Saud, T. [CSIR-National Physical Laboratory, New Delhi (India); Guru Govind Singh Indraprastha Univ., New Delhi (India)


    Concentrations of ambient NH{sub 3}, NO, NO{sub 2} and SO{sub 2} were measured over Bay of Bengal (BoB) during 28 December 2008 to 25 January 2009 to study their diurnal variation and relationship of NH{sub 3} with other trace gases over BoB. The measurements were done under the winter phase of Integrated Campaign on Aerosols and Radiation Budget (WICARB). For the first time, ambient NH{sub 3} was monitored precisely over BoB based on chemiluminescence method, having estimation efficiency more precise than the chemical trap method. The average concentration of ambient NH{sub 3}, NO, NO{sub 2} and SO{sub 2} were recorded as 4.78{+-}1.68, 1.89{+-}1.26, 0.31{+-}0.14 and 0.80{+-}0.30 {mu}gm{sup -3}, respectively, over BoB. The prominent latitudinal and longitudinal variations of the trace gases were observed over BoB, whereas NH{sub 3} and NO showed the non-significant diurnal variation. Results reveal that the concentration of ambient NH{sub 3} negatively correlated with ambient NO{sub 2} (r{sup 2} =.0.56), SO{sub 2} (r{sup 2} =.0.58) and ambient temperature (r{sup 2} =.0.27) during the study. (orig.)

  3. Fabrication and Electromagnetic Properties of Conjugated NH2-CuPc@Fe3O4 (United States)

    Yan, Liang; Pu, Zejun; Xu, Mingzhen; Wei, Renbo; Liu, Xiaobo


    Conjugated amino-phthalocyanine copper containing carboxyl groups/magnetite (NH2-CuPc@Fe3O4) has been fabricated from FeCl3·6H2O and NH2-CuPc via a simple solvothermal method and its electromagnetic properties investigated. Scanning electron microscopy and transmission electron microscopy revealed that the NH2-CuPc@Fe3O4 was a waxberry-like nanomaterial with NH2-CuPc molecules effectively embedded in the interior of Fe3O4 particles in the form of beads. Introduction of NH2-CuPc effectively improved the complementarity between the dielectric and magnetic losses of the system, resulting in excellent electromagnetic performance. The minimum reflection loss of the as-prepared composite reached -33.4 dB at 7.0 GHz for coating layer thickness of 4.0 mm and bandwidth below -10.0 dB (90% absorption) of up to 3.8 GHz. These results indicate that introduction of NH2-CuPc results in a composite with potential for use as an electromagnetic microwave absorption material.

  4. Effect of surface modification of activated carbon on its adsorption capacity for NH3

    Institute of Scientific and Technical Information of China (English)

    SHAN Xiao-mei; ZHU Shu-quan; ZHANG Wen-hui


    To investigate the effects of carbon surface characteristics on NH3 adsorption, coal-based and coconut shell activated carbons were modified by treatment with oxidants. The surface properties of the carbons were characterized by low temperature nitrogen sorption, by Boehm's titrations and by XPS techniques. NH3 adsorption isotherms of the original and the modified carbons were determined. The results show that the carbons were oxidized by HNO3 and (NH4)2S2O8, and that there was an increase in oxygen containing functional groups on the surface. However, the pore-size distribution of the coal-based carbons was changed after KMnO4 treatment. It was found that the NH3 adsorption capacity of the modified carbons was enhanced and that the most pronounced enhancement results from (NH4)2S2O8 oxidation. Under our experimental conditions, the capacity is positively corrected to the number of surface functional groups containing oxygen, and to the number of micro-pores. Furthermore, an empirical model of the relationship between NH3 adsorption and multiple factors on the carbon surface was fit using a complex regression method.

  5. Optical monitoring of CH3NH3PbI3 thin films upon atmospheric exposure (United States)

    Ghimire, Kiran; Zhao, Dewei; Cimaroli, Alex; Ke, Weijun; Yan, Yanfa; Podraza, Nikolas J.


    CH3NH3PbI3 perovskite films of interest for photovoltaic (PV) devices have been prepared by (i) vapor deposition and (ii) solution processing. Complex dielectric function (ε  =  ε 1  +  iε 2) spectra and structural parameters of the films have been extracted using near infrared to ultraviolet spectroscopic ellipsometry. In situ real time spectroscopic ellipsometry (RTSE) over a 48 h period has been performed on vapor deposited CH3NH3PbI3 after the deposition in normal atmospheric laboratory ambient conditions. Analysis of RTSE data for vapor deposited CH3NH3PbI3 film prepared under un-optimized conditions identifies phase segregated PbI2 and CH3NH3I at the substrate/film interface and unreacted PbI2 and CH3NH3I on the film surface. This analysis also provides the time dependence of the effective thicknesses of perovskite film, unreacted components, and phase segregated layers to track CH3NH3PbI3 decomposition.

  6. Infrared spectrum of the NH4-d(n)+ cation trapped in solid neon. (United States)

    Jacox, Marilyn E; Thompson, Warren E


    The NH4+ cation has been stabilized in solid neon in sufficient concentration for the identification of both of its infrared-active vibrational fundamentals, which appear within a few wavenumbers of the gas-phase band centers. Systematic alteration of the concentrations and positions of introduction of NH3 and H2 in the discharge sampling experiments demonstrated that the highest yield of NH4+ resulted when both the NH3 and the H2 were introduced downstream from a discharge through pure neon. In this configuration, each of these molecules can be ionized by excited neon atoms and their resonance radiation (16.6 eV to 16.85 eV), but fragmentation is minimized. Both infrared-active vibrational fundamentals of ND4+ and several fundamentals of each of the partially deuterium-substituted isotopomers of NH4+ were also identified. Evidence is presented for complexation of NH4+ with an H atom or with one or more H2 molecules.

  7. The NO + NH 3 reaction on Pt(100): steady state and oscillatory kinetics (United States)

    Lombardo, S. J.; Esch, F.; Imbihl, R.

    The NO + NH 3 reaction was investigated on a Pt(100) surface in the 10 -6 mbar range using Video-LEED, work function measurements and measurements of the product partial pressures of N 2 and H 2O. Sustained kinetic oscillations, as observed in the N 2, H 2O and work function signals, were detected between 425 and 450 K for pNO = 1.1 × 10 -6 mbar and pNH3 = 4.7 × 10 -6 mbar. The dependence of the oscillation period on temperature and on the {p NH 3/ }/{p NO} ratio was determined. In situ LEED measurements demonstrated that oscillations in the reaction rate are coupled to the 1 × 1 ⇄ hex phase transition. Isotopic exchange experiments with 15NO and 14NH 3 showed that depending on the temperature and p {NH 3/ }/{p NO} ratio, significant deviations from a random mixing of 15N and 14N on the surface occur. This is interpreted as indication for an attractive interaction between NO ad and NH xad ( x = 1-3).

  8. Photostriction of CH3NH3PbBr3 Perovskite Crystals

    KAUST Repository

    Wei, Tzu-Chiao


    Organic-inorganic hybrid perovskite materials exhibit a variety of physical properties. Pronounced coupling between phonon, organic cations, and the inorganic framework suggest that these materials exhibit strong light-matter interactions. The photoinduced strain of CH3 NH3 PbBr3 is investigated using high-resolution and contactless in situ Raman spectroscopy. Under illumination, the material exhibits large blue shifts in its Raman spectra that indicate significant structural deformations (i.e., photostriction). From these shifts, the photostrictive coefficient of CH3 NH3 PbBr3 is calculated as 2.08 × 10-8 m2 W-1 at room temperature under visible light illumination. The significant photostriction of CH3 NH3 PbBr3 is attributed to a combination of the photovoltaic effect and translational symmetry loss of the molecular configuration via strong translation-rotation coupling. Unlike CH3 NH3 PbI3 , it is noted that the photostriction of CH3 NH3 PbBr3 is extremely stable, demonstrating no signs of optical decay for at least 30 d. These results suggest the potential of CH3 NH3 PbBr3 for applications in next-generation optical micro-electromechanical devices.

  9. A rice transient assay system identifies a novel domain in NRR required for interaction with NH1/OsNPR1 and inhibition of NH1-mediated transcriptional activation

    Directory of Open Access Journals (Sweden)

    Chern Mawsheng


    Full Text Available Abstract Background Arabidopsis NPR1 is a master regulator of systemic acquired resistance. NPR1 binds to TGA transcription factors and functions as a transcriptional co-activator. In rice, NH1/OsNPR1 functions to enhance innate immunity. NRR disrupts NH1 function, when over-expressed. Results We have established a rice transient protoplast assay to demonstrate that NH1 is a transcriptional co-activator and that NRR represses NH1-mediated activation. We identified three NRR homologues (RH1, RH2, and RH3. RH1 and RH3, but not RH2, also effectively repress NH1-mediated transcriptional activation. NRR, RH1, RH2, and RH3 share sequence similarity in a region beyond the previously identified NPR1-interacting domain. This region is required for strong interaction with NH1. A double point mutation, W66A/F70A, in this novel NH1-interacting domain severely reduces interaction with NH1. Mutation W66A/F70A also greatly reduces the ability of NRR to repress NH1-mediated activation. RH2 carries a deviation (amino acids AV in this region as compared to consensus sequences (amino acids ED among NRR, RH1, and RH3. A substitution (AV to ED in RH2 results in strong binding of mutant RH2ED to NH1 and effective repression of NH1-mediated activation. Conclusions The protoplast-based transient system can be used to dissect protein domains associated with their functions. Our results demonstrate that the ability of NRR and its homologues to repress NH1-mediated transcriptional activation is tightly correlated with their ability to bind to NH1. Furthermore, a sequence is identified as a novel NH1-interacting domain. Importantly, this novel sequence is widely present in plant species, from cereals to castor bean plants, to poplar trees, to Arabidopsis, indicating its significance in plants.

  10. Interaction of NH3 with Cu-SSZ-13 Catalyst: A Complementary FTIR, XANES, and XES Study. (United States)

    Giordanino, Filippo; Borfecchia, Elisa; Lomachenko, Kirill A; Lazzarini, Andrea; Agostini, Giovanni; Gallo, Erik; Soldatov, Alexander V; Beato, Pablo; Bordiga, Silvia; Lamberti, Carlo


    In the typical NH3-SCR temperature range (100-500 °C), ammonia is one of the main adsorbed species on acidic sites of Cu-SSZ-13 catalyst. Therefore, the study of adsorbed ammonia at high temperature is a key step for the understanding of its role in the NH3-SCR catalytic cycle. We employed different spectroscopic techniques to investigate the nature of the different complexes occurring upon NH3 interaction. In particular, FTIR spectroscopy revealed the formation of different NH3 species, that is, (i) NH3 bonded to copper centers, (ii) NH3 bonded to Brønsted sites, and (iii) NH4(+)·nNH3 associations. XANES and XES spectroscopy allowed us to get an insight into the geometry and electronic structure of Cu centers upon NH3 adsorption, revealing for the first time in Cu-SSZ-13 the presence of linear Cu(+) species in Ofw-Cu-NH3 or H3N-Cu-NH3 configuration.

  11. Advection of NH3 over a pasture field and its effect on gradient flux measurements

    Directory of Open Access Journals (Sweden)

    M. A. Sutton


    Full Text Available Deposition of atmospheric ammonia (NH3 to semi-natural ecosystems leads to serious adverse effects, such as acidification and eutrophication. A step in quantifying such effects is the measurement of NH3 fluxes over semi-natural and agricultural land. However, measurement of NH3 fluxes over vegetation in the vicinity of strong NH3 sources is challenging, since NH3 emissions are highly heterogeneous. Indeed, under such conditions, local advection errors may alter the measured fluxes. In this study, local advection errors (ΔFz,adv were estimated over a 14 ha grassland field, which was successively cut and fertilised, as part of the GRAMINAE integrated Braunschweig experiment. The magnitude of ΔFz,adv was determined up to 810 m downwind from farm buildings emitting between 6.2 and 9.9 kg NH3 day−1. The GRAMINAE experiment provided a unique opportunity to compare two methods of estimating ΔFz,adv: one inference method based on measurements of horizontal concentration gradients, and one based on inverse dispersion modelling with a two-dimensional model. Two sources of local advection were clearly identified: the farm NH3 emissions leading to positive ΔFz,adv ("bias towards emissions" and field NH3 emissions, which led to a negative ΔFz,adv ("bias towards deposition". The local advection flux from the farm was in the range 0 to 27 ng NH3 m−2 s−1 at 610 m from the farm, whereas ΔFz,adv due to field emission was proportional to the local flux, and ranged between −209 and 13 ng NH3 m−2 s−1. The local advection flux ΔFz,adv was either positive or negative depending on the magnitude of these two contributions. The modelled and inferred advection errors agreed well. The inferred advection errors, relative to the vertical flux at 1 m height, were 52% on average, before the field was cut, and less than 2.1% when the field was fertilised. The variability of the advection errors in response to changes in micrometeorological conditions is also

  12. Silver separation by using Na2SO3 and NH3%用Na2SO3与NH3分银实验研究

    Institute of Scientific and Technical Information of China (English)

    张小林; 李伟; 宁瑞


    This paper studies the silver separation by using Na2SO3 and NH3 out of gold dregs chlorination in the anode slime treatment process. The effects of Na 2SO3 amount, pH, time on the silver separation effects, and the effects of formaldehyde reduction temperature, pH on the reduction rate are researched. We also investigates the effects of NH3 concentration, time on silver separation results and the effects of hydrazine hydrate amount, time and temperature on silver reduction rate. The results show that separating silver of Na2SO3-reduced by using formaldehyde, when the amount of Na 2SO3 is 1.3 times of the theoretical amount, pH is 9.2, and the leaching time is 4 h, the silver recovery rate can be up to 97.39 %, while the amount of formaldehyde (formaldehyde∶Ag=1∶2.5 ), pH is 10.5, the temperature is 30~40 ℃, reacted 4 h, the silver reduction rate can be up to 96.33 %; Separating silver of NH 3-reduced by using hydrazine hydrate, when the concentration of NH3 between 8 % to 10 %,and temperature is at room temperature, the reaction time is 4 h, the silver leaching rate can be up to 96.23 %, when the amount of hydrazine hydrate is 2 times of the theoretical amount, temperature is 60 ℃, restored 0.5 h, silver reduction rate can be up to 98.1%.%介绍了阳极泥处理过程中,氯化分金渣用Na2SO3分银与NH3分银的工艺过程;研究了Na2SO3分银Na2SO3用量、pH、时间对分银效果的影响,以及甲醛还原温度、pH对银还原率的影响,以及NH3分银NH3浓度、时间对分银效果的影响,并对水合肼还原时水合肼用量、时间、温度对银还原率进行了研究.结果表明,用Na2SO3分银-甲醛还原,当Na2SO3的用量为理论量1.3倍,pH 值为9.2,浸出时间4 h时,银浸出率可达97.39%,当甲醛用量为(甲醛∶银=1∶2.5),pH值为10.5,反应4 h,温度为30~40℃时,银还原率可达96.33%;用NH3分银-水合肼还原,当NH3浓度为8%~10%,温度

  13. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH sub 3

    Energy Technology Data Exchange (ETDEWEB)

    Gwo, Dz-Hung (Lawrence Berkeley Lab., CA (USA) California Univ., Berkeley, CA (USA). Dept. of Chemistry)


    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH{sub 3} and (NH{sub 3}){sub 2}, generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH{sub 3}, and the other six belong to (NH{sub 3}){sub 2}. To facilitate the intermolecular vibrational assignment for Ar--NH{sub 3}, a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH{sub 3} centered at 26.470633(17) cm{sup {minus}1} can correlate only to either the fundamental dimeric stretching band for the A{sub 2} states with the NH{sub 3} inversional quantum number v{sub i} = 1, or the K{sub a} = 0 {l arrow} 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface.

  14. The application of EDTA in drug delivery systems: doxorubicin liposomes loaded via NH4EDTA gradient

    Directory of Open Access Journals (Sweden)

    Song YZ


    Full Text Available Yanzhi Song,1 Zhenjun Huang,1 Yang Song,2 Qingjing Tian,1 Xinrong Liu,1 Zhennan She,1 Jiao Jiao,1 Eliza Lu,3 Yihui Deng11College of Pharmacy, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China; 2Jiangsu Hansoh Pharmaceutical Co., Ltd., Lianyungang, People’s Republic of China; 3Livzon Mabpharm Inc., Zhuhai, People’s Republic of ChinaAbstract: The applications of ethylenediaminetetraacetic acid (EDTA have been expanded from the treatment of heavy metal poisoning to chelation therapies for atherosclerosis, heart disease, and cancers, in which EDTA reduces morbidity and mortality by chelating toxic metal ions. In this study, EDTA was used in a drug delivery system by adopting an NH4EDTA gradient method to load doxorubicin into liposomes with the goal of increasing therapeutic effects and decreasing drug-related cytotoxicity. The particle size of the optimum NH4EDTA gradient liposomes was 79.4±1.87 nm, and the entrapment efficiency was 95.54%±0.59%. In vitro studies revealed that liposomes prepared using an NH4EDTA gradient possessed long-term stability and delayed drug release. The in vivo studies also showed the superiority of the new doxorubicin formulation. Compared with an equivalent drug dose (5 mg/kg prepared by (NH42SO4 gradient, NH4EDTA gradient liposomes showed no significant differences in tumor inhibition ratio, but cardiotoxicity and liposome-related immune organ damage were lower, and no drug-related deaths were observed. These results show that use of the NH4EDTA gradient method to load doxorubicin into liposomes could significantly reduce drug toxicity without influencing antitumor activity.Keywords: NH4EDTA, liposome, doxorubicin, ion gradient, antitumor activity, toxicity

  15. MARVEL analysis of the measured high-resolution spectra of 14NH3 (United States)

    Al Derzi, Afaf R.; Furtenbacher, Tibor; Tennyson, Jonathan; Yurchenko, Sergei N.; Császár, Attila G.


    Accurate, experimental rotational-vibrational energy levels and line positions, with associated labels and uncertainties, are reported for the ground electronic state of the symmetric-top 14NH3 molecule. All levels and lines are based on critically reviewed and validated high-resolution experimental spectra taken from 56 literature sources. The transition data are in the 0.7-17 000 cm-1 region, with a large gap between 7000 and 15 000 cm-1. The MARVEL (Measured Active Rotational-Vibrational Energy Levels) algorithm is used to determine the energy levels. Out of the 29 450 measured transitions 10 041 and 18 947 belong to ortho- and para-14NH3, respectively. A careful analysis of the related experimental spectroscopic network (SN) allows 28 530 of the measured transitions to be validated, 18 178 of these are unique, while 462 transitions belong to floating components. Despite the large number of spectroscopic measurements published over the last 80 years, the transitions determine only 30 vibrational band origins of 14NH3, 8 for ortho- and 22 for para-14NH3. The highest J value, where J stands for the rotational quantum number, for which an energy level is validated is 31. The number of experimental-quality ortho- and para-14NH3 rovibrational energy levels is 1724 and 3237, respectively. The MARVEL energy levels are checked against ones in the BYTe first-principles database, determined previously. The lists of validated lines and levels for 14NH3 are deposited in the Supporting Information to this paper. Combination of the MARVEL energy levels with first-principles absorption intensities yields a huge number of experimental-quality rovibrational lines, which should prove to be useful for the understanding of future complex high-resolution spectroscopy on 14NH3; these lines are also deposited in the Supporting Information to this paper.

  16. Structures and phases transition in hexylenediammonium pentachlorobismuthate (III) [NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}]BiCl{sub 5} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ouasri, A., E-mail: [Equipe de Physico-Chimie des Matériaux Inorganiques, Université Ibn Tofail, Faculté des Sciences, B. P. 133, Kenitra 14000 (Morocco); Département de Physique-Chimie, Centre Régional des Métiers de l' Education, et de la Formation, Souissi Rabat (Morocco); Jeghnou, H.; Rhandour, A. [Equipe de Physico-Chimie des Matériaux Inorganiques, Université Ibn Tofail, Faculté des Sciences, B. P. 133, Kenitra 14000 (Morocco); Roussel, P. [Unité de Catalyse et de Chimie du Solide, CNRS UMR 8181 (Equipe de Chimie du Solide), ENSCL, USTL, VILLENEUVE D' ASCQ Cedex 59655 (France)


    The crystal structure of [NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}]BiCl{sub 5} was determined at: 223 K [P2{sub 1}2{sub 1}2{sub 1} (Z=4), a=7.788(1), b=13.886(2), c=13.972(2) Å], 308 K [P2{sub 1}/n (Z=8), a=19.972(3), b=7.772(2), c=20.166(3) Å, β=92.32(1)°] and 378 K [Pnma (Z=4), a=13911(2), b=7.834(7), c=14.457(2) Å]. It was consisted of isolated (BiCl{sub 5}{sup 2−}){sub n} anionic chains composed by distorted octahedra BiCl{sub 6}{sup 3−} sharing two corners and {sup +}NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}{sup +} cations placed in the free cavities between anionic chains. In the β phase, there are two crystallographically inequivalent cations and two one-dimensional anionic chains (BiCl{sub 5}{sup 2−}){sub n} in which BiCl{sub 6}{sup 3−} octahedra was doubly tilted and simply tilted. Two structural phase transitions at low and high temperatures α (P2{sub 1}2{sub 1}2{sub 1}, 223 K)↔β (P2{sub 1}/n, 308 K)↔γ (Pnma, 373 K) are observed and discussed. It was crystallographically showed that both anionic and cationic entities contribute to phase transitions mechanisms. The BiCl{sub 6}{sup 3−} octahedra were found to posses significant distortions on decreasing temperature and became more distorted in α (223 K) phase. It is argued that these deformations are caused by weak to moderate N--H···Cl hydrogen bonding. - Graphical abstract: Projection of the crystal structure of [NH{sub 3}(CH{sub 2}){sub 6}NH{sub 3}]BiCl{sub 5} down the a axis at 208 K. Highlights: ► The crystal shows two phase transitions: α(223 K)↔β(308 K)↔γ(373 K). ► A discontinuous transition may be occurred between α and β phases. ► The α↔β and β↔γ phase transitions are of first order. ► Both anionic and cationic motions contribute to phase transition mechanisms. ► The BiCl{sub 6}{sup 3−} octahedra showed significant distortions on decreasing temperature.

  17. Photoelectric characteristics of CH3NH3PbI3/p-Si heterojunction (United States)

    Yamei, Wu; Ruixia, Yang; Hanmin, Tian; Shuai, Chen


    Organic-inorganic hybrid perovskite CH3NH3PbI3 film is prepared on p-type silicon substrate using the one-step solution method to form a CH3NH3PbI3/p-Si heterojunction. The film morphology and structure are characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The photoelectric properties of the CH3NH3PbI3/p-Si heterojunction are studied by testing the current-voltage (I-V) with and without illumination and capacitance-voltage (C-V) characteristics. It turns out from the I-V curve without illumination that the CH3NH3PbI3/p-Si heterojunction has a rectifier feature with the rectification ratio over 70 at the bias of ±5 V. Also, there appears a photoelectric conversion phenomenon on this heterojunction with a short circuit current (Isc) of 0.16 μA and an open circuit voltage (Voc) of about 10 mV The high frequency C-V characteristic of the Ag/CH3NH3PbI3/p-Si heterojunction turns out to be similar to that of the metal-insulator-semiconductor (MIS) structure, and a parallel translation of the C-V curve along the forward voltage axis is found. This parallel translation means the existence of defects at the CH3NH3PbI3/p-Si interface and positive fixed charges in the CH3NH3PbI3 layer. The defects at the interface of the CH3NH3PbI3/p-Si heterojunction result in the dramatic decline of the Voc. Besides, the C-V test of CH3NH3PbI3 film shows a non-linear dielectric property and the dielectric value is about 4.64 as calculated. Project supported by the Hebei Province Natural Science Foundation of China (No. F2014202184) and the Tianjin Natural Science Foundation of China (No. 15JCZDJC37800).

  18. NH 3 soil and soil surface gas measurements in a triticale wheat field (United States)

    Neftel, A.; Blatter, A.; Gut, A.; Högger, D.; Meixner, F.; Ammann, C.; Nathaus, F. J.

    We present a new approach for a continuous determination of NH 3 concentration in the open pore space of the soil and on the soil surface. In a semi-permeable membrane of 0.5 m length a flow of 0.5 s1pm maintained. In the tube the NH 3 concentration adjusts itself to the surrounding air concentration by diffusion through the membrane. Continuous measurements have been performed in a triticale wheat field over a period of several weeks in a field experiment at Bellheim (FRG) during June and July 1995 within the frame of the European program EXAMINE (Exchange of Atmospheric Ammonia with European Ecosystems). Soil concentrations are generally below the detection limit of 0.1 μg m -3. We conclude, that the investigated soil is generally a sink for NH 3. The NH 3 concentration on the soil surface shows a diurnal variation due to a combination of physico-chemical desorption and adsorption phenomena associated with changes in wetness of the surrounding surfaces and the NH 3 concentration in the canopy.

  19. Visible blind ultraviolet photodetector based on CH3NH3PbCl3 thin film. (United States)

    Wang, Wenzhen; Xu, Haitao; Cai, Jiang; Zhu, Jiabin; Ni, Chaowei; Hong, Feng; Fang, Zebo; Xu, Fuzong; Cui, Siwei; Xu, Run; Wang, Linjun; Xu, Fei; Huang, Jian


    We report a prototypical device of CH3NH3PbCl3 film ultraviolet photodetectors that were fabricated with a coplanar metal-semiconductor-metal Au interdigital electrode configuration. Pure phase CH3NH3PbCl3 films with a good crystallinity were formed by a hybrid sequential deposition process featured with inter-diffusion of PbCl2 and CH3NH3Cl upon annealing. The CH3NH3PbCl3 film photodetector exhibits a high responsivity of 7.56 A /W at 360 nm, a ultraviolet/visible rejection ratio (R360 nm/R500 nm) was about two orders of magnitude and fast response speed with a rising time of 170 μs and a decay time of 220 μs. All the above results demonstrate CH3NH3PbCl3 film photodetector as a competitive candidate in the application of visible blind UV detectors.

  20. Electric polarization of CH3NH3PbI3 and enhancement by Cl substitution (United States)

    Yan, Wen-Li; Lu, Guang-Hong; Liu, Feng

    As a prototype of organic-inorganic hybrid perovskite, CH3NH3PbI3 has attracted extensive attention recently due to its applications in high power-conversion-efficiency solar cells. In comparison with its inorganic perovskite counterparts such as CsPbI3, the organic cation CH3NH3+ is expected to play multiple important roles in distorting crystal structures and thus band structures as well as creating local electrically polarized domains to help separate charge carriers. Using first-principles method and berry phase theory, the electric polarization vectors of CH3NH3PbI3 have been calculated. The off-center displacement of Pb within the PbI6 octahedral is shown to introduce major intrinsic polarization, with additional contributions from off-center displacement of CH3NH3+ within PbI3 cage and charge polarization within the organic cation. With chlorine substitution of iodine, the electronegativity difference between halogen and Pb becomes larger, and the lattice distortion and hence the electric polarization increases, which provides a possible mechanism to further assist charge carrier separation in solar cell devices. This is consistent with enhanced photovoltaics properties of CH3NH3PbI3-xClx found in recent experiments. This work is supported by China Scholarship Council (Grant No. 201306020117) and US DOE-BES (Grant No. DE-FG02-04ER46148).

  1. Role of the NH2 -terminal fragment of dentin sialophosphoprotein in dentinogenesis. (United States)

    Gibson, Monica P; Liu, Qilin; Zhu, Qinglin; Lu, Yongbo; Jani, Priyam; Wang, Xiaofang; Liu, Ying; Paine, Michael L; Snead, Malcolm L; Feng, Jian Q; Qin, Chunlin


    Dentin sialophosphoprotein (DSPP) is a large precursor protein that is proteolytically processed into a NH2 -terminal fragment [composed of dentin sialoprotein (DSP) and a proteoglycan form (DSP-PG)] and a COOH-terminal fragment [dentin phosphoprotein (DPP)]. In vitro studies indicate that DPP is a strong initiator and regulator of hydroxyapatite crystal formation and growth, but the role(s) of the NH2 -terminal fragment of DSPP (i.e., DSP and DSP-PG) in dentinogenesis remain unclear. This study focuses on the function of the NH2 -terminal fragment of DSPP in dentinogenesis. Here, transgenic (Tg) mouse lines expressing the NH2 -terminal fragment of DSPP driven by a 3.6-kb type I collagen promoter (Col 1a1) were generated and cross-bred with Dspp null mice to obtain mice that express the transgene but lack the endogenous Dspp (Dspp KO/DSP Tg). We found that dentin from the Dspp KO/DSP Tg mice was much thinner, more poorly mineralized, and remarkably disorganized compared with dentin from the Dspp KO mice. The fact that Dspp KO/DSP Tg mice exhibited more severe dentin defects than did the Dspp null mice indicates that the NH2 -terminal fragment of DSPP may inhibit dentin mineralization or may serve as an antagonist against the accelerating action of DPP and serve to prevent predentin from being mineralized too rapidly during dentinogenesis.

  2. Effects of NH3 on N2O Formation and Destruction in Fluidized Bed Coal Combustion

    Institute of Scientific and Technical Information of China (English)

    JianWeiYuan; BoFeng; 等


    The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper,It is found that NH3 has contributions not only to N2O formation,but also to N2O destruction in certain conditions.The main product of homogeneous NH3 oxidation is found to be NO rather than N2O,but some bed materials and suplhur sorbents have catalytic contributions to N2O formation from NH3 oxidation.In reduction atmosphere,NH3 can promote the KC destruction.It is deduced that the ammonia injection into fluidized bed coal combustion flue gas can decrease both NOx and N2O emissions.The ammonia injection process is kinetically simulated in this study,and the reduction.rates of NOx and N2O are found to depend on temperature,O2 concentration,initial NOx and N2O concentrations,and amount of injected ammonia.

  3. Low and room temperature photoabsorption cross sections of NH3 in the UV region (United States)

    Chen, F. Z.; Judge, D. L.; Wu, C. Y. R.; Caldwell, J.


    Using synchrotron radiation as a continuum light source, we have measured the absolute absorption cross sections of NH3 with a spectral bandwidth (FWHM) of 0.5 Å. The photoabsorption cross sections of NH3 have been measured from 1750 to 2250 Å under temperature conditions of 295, 195, and 175 K. Significant temperature effects in the absorption threshold region which are mainly due to the presence of hot band absorption are observed. The cross section value at peaks and valleys for the vibrational progressions of the (0,0) to (4,0) bands vary between -80% and +40% as the temperature of NH3 changes from 295 to 175 K. In contrast to this, the changes of cross section values, Pc,T, are found to vary less than 20% for the (v', 0) vibrational progressions with v' >= 5. The measured separations between the doublet features of the (0,0), (1,0), and (2,0) bands are found to decrease as the temperature of NH3 decreases. The shifts of peak positions of Pc,T with respect to the corresponding room temperature absorption peaks show a sudden change at v' = 3 which appears to agree with the trend observed in the homogeneous line widths of the vibrational bands of NH3 ([Vaida et al., 1987]; [Ziegler, 1985]; [Ziegler, 1986]). The unusual behavior of the line widths has been attributed to the A~ state potential surface which has a dissociation barrier.

  4. Enhanced PEDOT adhesion on solid substrates with electrografted P(EDOT-NH2) (United States)

    Ouyang, Liangqi; Wei, Bin; Kuo, Chin-chen; Pathak, Sheevangi; Farrell, Brendan; Martin, David C.


    Conjugated polymers, such as poly(3,4-ethylene dioxythiophene) (PEDOT), have emerged as promising materials for interfacing biomedical devices with tissue because of their relatively soft mechanical properties, versatile organic chemistry, and inherent ability to conduct both ions and electrons. However, their limited adhesion to substrates is a concern for in vivo applications. We report an electrografting method to create covalently bonded PEDOT on solid substrates. An amine-functionalized EDOT derivative (2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methanamine (EDOT-NH2), was synthesized and then electrografted onto conducting substrates including platinum, iridium, and indium tin oxide. The electrografting process was performed under slightly basic conditions with an overpotential of ~2 to 3 V. A nonconjugated, cross-linked, and well-adherent P(EDOT-NH2)–based polymer coating was obtained. We found that the P(EDOT-NH2) polymer coating did not block the charge transport through the interface. Subsequent PEDOT electrochemical deposition onto P(EDOT-NH2)–modified electrodes showed comparable electroactivity to pristine PEDOT coating. With P(EDOT-NH2) as an anchoring layer, PEDOT coating showed greatly enhanced adhesion. The modified coating could withstand extensive ultrasonication (1 hour) without significant cracking or delamination, whereas PEDOT typically delaminated after seconds of sonication. Therefore, this is an effective means to selectively modify microelectrodes with highly adherent and highly conductive polymer coatings as direct neural interfaces. PMID:28275726

  5. A Complete Survey of the Central Molecular Zone in NH3

    CERN Document Server

    Nagayama, Takumi; Handa, Toshihiro; Iahak, Hayati Bebe Hajra; Sawada, Tsuyoshi; Miyaji, Takeshi; Koyama, Yasuhiro


    We present a map of the major part of the central molecular zone (CMZ) of simultaneous observations in the NH3 (J,K) = (1,1) and (2,2) lines using the Kagoshima 6-m telescope. The mapped area is -1.000 80 K contain 75% and 25% of the total NH3 flux, respectively. These temperatures indicate that the dense molecular gas in the CMZ is dominated by gas that is warmer than the majority of the dust present there. A comparison with the CO survey by Sawada et al. (2001) shows that the NH3 emitting region is surrounded by a high pressure region on the l-v plane. Although NH3 emission traces dense gas, it is not extended into a high pressure region. Therefore, the high pressure region is less dense and has to be hotter. This indicates that the molecular cloud complex in the Galactic center region has a ``core'' of dense and warm clouds which are traced by the NH3 emission, and an ``envelope'' of less dense and hotter gas clouds. Besides heating by ambipolar diffusion, the hot plasma gas emitting the X-ray emission ma...

  6. Intramolecular SN2 reaction caused by photoionization of benzene chloride-NH3 complex: direct ab initio molecular dynamics study. (United States)

    Tachikawa, Hiroto


    Ionization processes of chlorobenzene-ammonia 1:1 complex (PhCl-NH3) have been investigated by means of full dimensional direct ab initio molecular dynamics (MD) method, static ab initio calculations, and density functional theory (DFT) calculations. The static ab initio and DFT calculations of neutral PhCl-NH3 complex showed that one of the hydrogen atoms of NH3 orients toward a carbon atom in the para-position of PhCl. The dynamics calculation for ionization of PhCl-NH3 indicated that two reaction channels are competitive with each other as product channels: one is an intramolecular SN2 reaction expressed by a reaction scheme [PhCl-NH3]+-->SN2 intermediate complex-->PhNH3++Cl, and the other is ortho-NH3 addition complex (ortho complex) in which NH3 attacks the ortho-carbon of PhCl+ and the trajectory leads to a bound complex expressed by (PhCl-NH3)+. The mechanism of the ionization of PhCl-NH3 is discussed on the basis of the theoretical results.

  7. Sensitive measurement of NH4+ 15N/14N (delta 15NH4+) at natural abundance levels in fresh and saltwaters. (United States)

    Zhang, Lin; Altabet, Mark A; Wu, Taixing; Hadas, Ora


    We report a new method for determining the 15N/14N of NH4+ at natural abundance level in both freshwater and seawater. NH4+ is first quantitatively oxidized to NO2- by hypobromite (BrO-) at pH approximately 12. After the addition of sodium arsenite to consume excess BrO-, yield is verified by colorimetric NO2- determination. NO2- is further reduced to N2O using a 1:1 sodium azide and acetic acid buffer solution using previously established procedures. The product N2O is then analyzed for isotopic composition using a continuous flow purge and cryogenic trap system coupled to an isotope ratio mass spectrometer. Reliable delta 15N values (standard deviation is 0.3 per thousand or better) are obtained over an NH4+ concentration range of 0.5-10 microM using 20 mL volumes of either freshwater or seawater samples. Higher concentration samples are readily diluted to lower concentration. Preexisting NO2- is removed by treatment with sulfanilic acid. There is no interference from any of the nitrogen-containing compounds tested except short-chain aliphatic amino acids (i.e., glycine) which typically are present at very low environmental concentrations. As compared to published methods, our approach is more robust, readily applicable at low concentrations and small sample volumes, and requires less time for preparation and analysis.

  8. Perovskite metal formate framework of [NH2-CH(+)-NH2]Mn(HCOO)3]: phase transition, magnetic, dielectric, and phonon properties. (United States)

    Mączka, Mirosław; Ciupa, Aneta; Gągor, Anna; Sieradzki, Adam; Pikul, Adam; Macalik, Bogusław; Drozd, Marek


    We report the synthesis, crystal structure, and thermal, dielectric, phonon, and magnetic properties of [NH2-CH(+)-NH2][Mn(HCOO)3] (FMDMn). The anionic framework of [(Mn(HCOO)3(-)] is counterbalanced by formamidinium (FMD(+)) cations located in the cavities of the framework. These cations form extensive N-H···O hydrogen bonding with the framework. The divalent manganese ions have octahedral geometry and are bridged by the formate in an anti-anti mode of coordination. We have found that FMDMn undergoes a structural phase transition around 335 K. According to the X-ray diffraction, the compound shows R3̅c symmetry at 355 K and C2/c symmetry at 295 and 110 K. The FMD(+) cations are dynamically disordered in the high-temperature phase, and the disorder leads to very large bandwidths of Raman and IR bands corresponding to vibrations of the NH2 groups. Temperature-dependent studies show that the phase transition in FMDMn is associated with ordering of the FMD(+) cations. Detailed analysis shows, however, that these cations still exhibit some reorientational motions down to about 200 K. The ordering of the FMD(+) cations is associated with significant distortion of the anionic framework. On the basis of the magnetic data, FMDMn is a weak ferromagnet with the critical temperature Tc = 8.0 K.

  9. Nature of phase transitions in ammonium oxofluorovanadates, a vibrational spectroscopy study of (NH4)3VO2F4 and (NH4)3VOF5 (United States)

    Gerasimova, Yu. V.; Oreshonkov, A. S.; Laptash, N. M.; Vtyurin, A. N.; Krylov, A. S.; Shestakov, N. P.; Ershov, A. A.; Kocharova, A. G.


    Two ammonium oxofluorovanadates, (NH4)3VO2F4 and (NH4)3VOF5, have been investigated by temperature-dependent infrared and Raman spectroscopy methods to determine the nature of phase transitions (PT) in these compounds. Dynamics of quasioctahedral groups was simulated within the framework of semi-empirical approach, which justified the cis-conformation of VO2F43 - (C2v) and the C4v geometry of VOF53 -. The observed infrared and Raman spectra of both compounds at room temperature (RT) revealed the presence at least of two crystallographically independent octahedral groups. The first order PT at elevated temperatures is connected with a complete dynamic disordering of these groups with only single octahedral state. At lower temperatures, the octahedra are ordered and several octahedral states appear. This PT is the most pronounced in the case of (NH4)3VOF5, when at least seven independent VOF53 - octahedra are present in the structure below 50 K, in accordance with the Raman spectra. Ammonium groups do not take part in PTs at higher and room temperatures but their reorientational motion freezes at lower temperatures.

  10. Heterolytic cleavage of ammonia N-H bond by bifunctional activation in silica-grafted single site Ta(V) imido amido surface complex. Importance of the outer sphere NH3 assistance

    KAUST Repository

    Gouré, Eric


    Ammonia N-H bond is cleaved at room temperature by the silica-supported tantalum imido amido complex [(≡SiO)2Ta(NH)(-NH2)], 2, if excess ammonia is present, but requires 150 °C to achieve the same reaction if only one equivalent NH3 is added to 2. MAS solid-state 15N NMR and in situ IR spectroscopic studies of the reaction of either 15N or 2H labeled ammonia with 2 show that initial coordination of the ammonia is followed by scrambling of either 15N or 2H among ammonia, amido and imido groups. Density functional theory (DFT) calculations with a cluster model [{(μ-O)[(H3SiO) 2SiO]2}Ta(NH)(-NH2)(NH3)], 2 q·NH3, show that the intramolecular H transfer from Ta-NH2 to TaNH is ruled out, but the H transfers from the coordinated ammonia to the amido and imido groups have accessible energy barriers. The energy barrier for the ammonia N-H activation by the Ta-amido group is energetically preferred relative to the Ta-imido group. The importance of excess NH3 for getting full isotope scrambling is rationalized by an outer sphere assistance of ammonia acting as proton transfer agent, which equalizes the energy barriers for H transfer from coordinated ammonia to the amido and imido groups. In contrast, additional coordinated ammonia does not favor significantly the H transfer. These results rationalize the experimental conditions used. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.

  11. Structural Studies of NH4-exchanged Natrolites at Ambient Conditions and High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Y Lee; D Seoung; Y Jang; J Bai; Y Lee


    We report here for the first time that fully and partially NH{sub 4}-exchanged natrolites can be prepared in hydrated states using the solution exchange method with potassium-natrolite. The structural models of the as-prepared hydrated phases and their dehydrated forms at elevated temperature were refined in space group Fdd2 using in situ synchrotron X-ray powder diffraction data and Rietveld methods. The unit-cell volumes of the hydrated NH{sub 4}-exchanged natrolites at ambient conditions, (NH{sub 4}){sub 16(2)}Al{sub 16}Si{sub 24}O{sub 80}{center_dot}14.1(9)H{sub 2}O and (NH{sub 4}){sub 5.1(1)}K{sub 10.9(1)}Al{sub 16}Si{sub 24}O{sub 80}{center_dot}15.7(3)H{sub 2}O, are found to be larger than that the original sodium-natrolite by ca. 15.6% and 12.8%, respectively. Upon temperature increase, the fully NH{sub 4}-exchanged natrolite undergoes dehydration at ca. 150 C with ca. 16.4% contraction in the unit-cell volume. The dehydrated phase of the fully NH{sub 4}-exchanged natrolite exhibits marginal volume expansion up to 425 C and then becomes amorphized during temperature decrease and exposure to atmospheric condition. In the case of the partially NH{sub 4}-exchanged natrolite, the dehydration starts from ca. 175 C with {approx}15.1% volume contraction and leads to a partial phase separation to show a phase related to the dehydrated K-natrolite. The degree of the phase separation decreases with temperature increase up to 475 C, concomitant to the gradual volume contraction occurring in the partially NH{sub 4}-exchanged natrolite in the dehydrared state. Upon temperature decrease and exposure to atmospheric condition, only the dehydrated K-natrolite is recovered as a crystalline phase from the partially NH{sub 4}-exchanged natrolite. In the hydrated model of the fully NH{sub 4}-exchanged natrolite, the ammonium cations and water molecules are statistically distributed along the elliptical channels, similar to the disordered pattern observed in natrolites exchanged

  12. A Review & Assessment of Current Operating Conditions Allowable Stresses in ASME Section III Subsection NH

    Energy Technology Data Exchange (ETDEWEB)

    R. W. Swindeman


    The current operating condition allowable stresses provided in ASME Section III, Subsection NH were reviewed for consistency with the criteria used to establish the stress allowables and with the allowable stresses provided in ASME Section II, Part D. It was found that the S{sub o} values in ASME III-NH were consistent with the S values in ASME IID for the five materials of interest. However, it was found that 0.80 S{sub r} was less than S{sub o} for some temperatures for four of the materials. Only values for alloy 800H appeared to be consistent with the criteria on which S{sub o} values are established. With the intent of undertaking a more detailed evaluation of issues related to the allowable stresses in ASME III-NH, the availabilities of databases for the five materials were reviewed and augmented databases were assembled.

  13. Laser Raman and ac impedance spectroscopic studies of PVA: NH4NO3 polymer electrolyte. (United States)

    Hema, M; Selvasekarapandian, S; Hirankumar, G; Sakunthala, A; Arunkumar, D; Nithya, H


    Ion conducting polymer electrolyte PVA:NH(4)NO(3) has been prepared by solution casting technique and characterized using XRD, Raman and ac impedance spectroscopic analyses. The amorphous nature of the polymer films has been confirmed by XRD and Raman spectroscopy. An insight into the deconvoluted Raman peaks of upsilon(1) vibration of NO(3)(-) anion for the polymer electrolyte reveals the dominancy of ion aggregates at higher NH(4)NO(3) concentration. From the ac impedance studies, the highest ion conductivity at 303 K has been found to be 7.5x10(-3)Scm(-1) for 80PVA:20NH(4)NO(3). The conductivity of the polymer electrolytes has been found to depend on the degree of dissociation of the salt in the host polymer matrix. The combination of the above-mentioned analyses has proven worth while and in fact necessary in order to achieve better understanding of these complex systems.

  14. Ammonothermal synthesis of GaN using Ba(NH2)2 as mineralizer (United States)

    Hertrampf, J.; Alt, N. S. A.; Schlücker, E.; Knetzger, M.; Meissner, E.; Niewa, R.


    It is demonstrated that hexagonal GaN can be obtained under ammonothermal conditions (125 MPa and 723 K) using Ba(NH2)2 as mineralizer. The hexagonal wurtzite-type GaN crystallites are several μm in diameter, as examined by scanning electron microscopy. This is to our knowledge the first successful ammonothermal GaN synthesis using an alkaline-earth metal as mineralizer. Ba[Ga(NH2)4]2 was identified as intermediate species in the ammonothermal synthesis process. The formation of h-GaN using Sr(NH2)2 as mineralizer was indicated only at higher temperatures above 1000 K.

  15. Synthesis of mesoporous NH2-SBA-15 by a simple and efficient strategy (United States)

    You, Long; Yuan, Fang; Ma, Feng


    Amine modified SBA-15 (NH2-SBA-15) was synthesized by a simple and efficient strategy, that is, activation at first and followed by amination. The samples were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), environmental scanning electron microscopy (ESEM), thermo gravimetric (TG) analysis, and nitrogen adsorption. Results show that the as-prepared NH2-SBA-15 possessed a large surface area, stable skeleton structure, and high amino contents. Moreover, the CO2 temperature programmed desorption (CO2-TPD) experiments of the as-prepared NH2-SBA-15 were studied, and the results show that the introduction of amino groups results in the increase of the basic sites of SBA-15, which is beneficial to the adsorption of CO2.

  16. Site specific reactivity of Cu-CHA with NO, NH3 and O2

    DEFF Research Database (Denmark)

    Godiksen, Anita; Isaksen, Oliver L.; Rasmussen, Søren B.


    In-situ electron paramagnetic resonance (EPR) spectroscopy was applied to dilute copper chabazite (CHA) zeolites under gas flows relevant for the selective catalytic reduction of NO with ammonia (NH3-SCR). Under both reducing and oxidizing conditions, we observed differences in reactivity between...... of oxidation differs significantly between reaction with O2 alone and with NO+O2 together. Thus it was revealed that [Cu(NH3)2]+ complexes, which are regarded to be only weakly associated with the framework, nevertheless have different reactivity depending on the Al distribution in the proximity. The observed...... differences in reactivity of copper sites has implications for the mechanistic understanding of NH3-SCR with Cu-zeolites....

  17. Formation of NH{sub 3} during the pyrolysis of a brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Li, C.Z.; Pang, Y.; Li, X.G. [Monash Univ., Clayton, Victoria (Australia). Dept. of Chemical Engineering


    Emissions of oxides of nitrogen (NO, NO{sub 2} and N{sub 2}O) from power generation using coal are an important environmental problem, contributing to the formation of photochemical smog and acid rain or to the enhancement of greenhouse effects and to the enhanced depletion of stratospheric ozone. During pyrolysis, the nitrogen in coal, as a part of coal organic matter, is converted into NOx precursors (eg. NH{sub 3}, HCN, HNCO and the nitrogen in tar and char). These NOx precursors may then be converted into either NOx or N{sub 2} during subsequent combustion or gasification/combustion. The conversion efficiency of these NOx precursors into NOx depends strongly upon the type of NOx precursor. Knowledge of the formation of these NOx precursors during pyrolysis is therefore essential for the accurate predictions of NOx emissions from large scale power plants, and therefore for the development of optimum strategies for NOx reduction. Formation of NH{sub 3} during the pyrolysis of a Victorian brown coal (Loy Yang) has been studied in a novel reactor. The experimental results obtained suggest that a considerable amount of the nitrogen in the nascent char could be converted into NH{sub 3} if the char is held at high temperatures for a long period of time. The formation of NH{sub 3} from the thermal cracking of char was seen to last for more than an hour even at temperatures as high as 700--900 C. The experimental results seem to suggest that the differences in reactor geometries would account at least partially for some of the discrepancies in the literature regarding the formation of NH{sub 3} during the pyrolysis of coals. It is thought that NH{sub 3} may be formed from the hydrogenation of the N sites in the char by the active hydrogen generated from the thermal cracking of the char.

  18. A flexible and robust neural network IASI-NH3 retrieval algorithm (United States)

    Whitburn, S.; Van Damme, M.; Clarisse, L.; Bauduin, S.; Heald, C. L.; Hadji-Lazaro, J.; Hurtmans, D.; Zondlo, M. A.; Clerbaux, C.; Coheur, P.-F.


    In this paper, we describe a new flexible and robust NH3 retrieval algorithm from measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The method is based on the calculation of a spectral hyperspectral range index (HRI) and subsequent conversion to NH3 columns via a neural network. It is an extension of the method presented in Van Damme et al. (2014a) who used lookup tables (LUT) for the radiance-concentration conversion. The new method inherits the advantages of the LUT-based method while providing several significant improvements. These include the following: (1) Complete temperature and humidity vertical profiles can be accounted for. (2) Third-party NH3 vertical profile information can be used. (3) Reported positive biases of LUT retrieval are reduced, and finally (4) a full measurement uncertainty characterization is provided. A running theme in this study, related to item (2), is the importance of the assumed vertical NH3 profile. We demonstrate the advantages of allowing variable profile shapes in the retrieval. As an example, we analyze how the retrievals change when all NH3 is assumed to be confined to the boundary layer. We analyze different averaging procedures in use for NH3 in the literature, introduced to cope with the variable measurement sensitivity and derive global averaged distributions for the year 2013. A comparison with a GEOS-Chem modeled global distribution is also presented, showing a general good correspondence (within ±3 × 1015 over most of the Northern Hemisphere. However, IASI finds mean columns about 1-1.5 × 1016 (˜50-60%) lower than GEOS-Chem for India and the North China plain.

  19. NH3 Volatilization from Aboveground Plants of Winter Wheat During Late Growing Stages

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-hui; LI Sheng-xiu


    Ammonia volatilized from aboveground parts of winter wheat was collected with an enclosuregrowth chamber and measured from jointing to maturing stage. The results showed that ammonia releasedfrom unfertilized plants grown in high and low fertility soils remained at low rates of 2.3 and 0.9 μg NH3 40plant-1 h-1 respectively at late filling stage. However, fertilized plants rapidly increased the rates to 43.4 and52.2 μg NH3 40 plant-1 h-1 in the high and low fertility soils, respectively, at the same period. The released a-mount was different in different parts of plants. At filling stage, lower senescing stems and leaves volatilizedmore ammonia than upper parts, i.e. , ears and flag leaves that grew normally, with an average of 1.4 and0.7 μg NH3 20 plant-1 h-1 respectively, strongly suggesting that it was the senile organs that released largeamounts of ammonia. At the grain filling stage, shortage of water supply (drought stress) reduced ammoniavolatilization. The average rate of ammonia released under water stress was 0.9 μg NH3 40 plant-1 h-1 , but 1.2μg NH3 40 plant-1 h-1 with moderate water supply. Application of N together with P fertilizer resulted in ahigher ammonia volatilization than N fertilization alone at the maturing stage. The average rate released was135.3 μg NH3 40 plant-1 h-1 when 0.4 g N and 0.13 g P had been added to per kg soil, while 33.7 μg when0.4 g N added alone. Ammonia volatilization from plants was closely related with plant biomass and N up-take; P fertilization increased plant biomass and N uptake and therefore increased its release.

  20. Synthesis, structure, lattice energy and enthalpy of 2D hybrid perovskite [NH3(CH2)4NH3]CoCl4, compared to [NH3(CH2)nNH3]CoCl4, n=3-9 (United States)

    Abdel-Aal, Seham K.; Abdel-Rahman, Ahmed S.


    A new organic-inorganic 2D hybrid perovskite [NH3(CH2)4NH3]CoCl4,1,4butane diammonium tetra-chlorocobaltate, has been synthesized. Blue prismatic single crystals were grown from ethanolic solution in 1:1 stoichiometric ratio (organic/inorganic) by gradual cooling to room temperature after heating at 70 °C for 1 h. The hybrid crystallizes in a triclinic phase with the centrosymetric space group P 1 bar . Its unit cell parameters are a=7.2869 (2) Å, b=8.1506 (2) Å, c=10.4127 (3) Å, α=77.2950 (12)°, β=80.0588 (11)°, γ=82.8373 (12)° and Z=2. The final R factor is 0.064. The structure consists of organic dications [NH3(CH2)4NH3]2+ which act as spacer between layers of inorganic dianions [CoCl4]2- in which CoII ions are coordinated by four Cl atoms in an isolated tetrahedral structure. The organic and inorganic layers form infinite 2D sheets which are parallel to the ac plane, stacking alternatively along the b-axis, and are connected via N-H…. Cl hydrogen bonds. The lamellar structure of the 1,4 butane diammonium tetrachlorocobaltate hybrid is typically considered as naturally self-assembled multiple quantum wells (MQW). The calculated lattice potential energy Upot (kJ/mol) and lattice enthalpy ΔHL (kJ/mol) are inversely proportional to the molecular volume Vm (nm3) of perovskite hybrid of the formula [NH3(CH2)nNH3]CoCl4, n=3-9.

  1. Quantum IR line list of NH3 and isotopologues for ISM and dwarf studies (United States)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.; Sung, Keeyoon; Brown, Linda R.


    Ammonia (NH3) was the first polyatomic molecule observed in the ISM. Its importance in interstellar molecules is only second to CO because its rovibrational spectroscopic signature can be used very effectively at deducing the conditions of the interstellar environment such as temperature and density, and because it is found in so many different interstellar objects in a wide temperature range. However, experimental determination of NH3 IR spectra is extremely difficult due to the large-amplutide inversion vibration, and the existing HITRAN2008 database for NH3 is limited in temperature, coverage, completeness, and accuracy. With rapid progress in theoretical chemistry and computational resources, now we are able to generate a highly reliable/accurate IR line list of NH3 (and its isotopologues) for astronomical studies. Exact quantum rovibrational computations on an empirically refined potential energy surface (with nonadiabatic corrections included) have achieved accuracies of 0.02-0.05 cm-1 (for line position) and better than 85-95% (for line intensity) for both NH3 and 15NH3 spectra. The unique feature of our work is that our predictions are essentially as accurate as reproducing existing measurements, suitable for synthetic simulation of various astrophysical environments or objects. The reliabilty and accuracy of our predictions for missing bands and higher energies computed on HSL-2 (Fig. 1) have been proved by the most recent high-resolution experiments and extended up to 7000 cm-1. See Huang et al. 2008, Huang et al. 2011, & Sung et al. 2012 for more details.

  2. LPG and NH3 sensing characteristics of DC electrochemically deposited Co3O4 films (United States)

    Shelke, P. N.; Khollam, Y. B.; Gunjal, S. D.; Koinkar, P. M.; Jadkar, S. R.; Mohite, K. C.


    Present communication reports the LPG and NH3 sensing properties of Co3O4 films prepared on throughly cleaned stainless steel (SS) and copper (CU) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from 25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co3O4 in all films. The LPG and NH3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH3 gas. In case of NH3 gas (conc. 150 ppm) and LPG gas (conc. 60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3-5 min.) is found to be much higher than the recovery time (30-50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH3 gas. Further, repeatability-reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions.

  3. Effect of Organic Acids and Protons on Release of Non-Exchangeable NH4+ in Flooded Paddy Soils

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-Song; SHAO Xing-Hua; LIN Xian-Yong; H. W. SCHERER


    In a model experiment, which imitated the rhizosphere of rice, the effect of organic acids (oxalic acid, citric acid) and protons on the release of non-exchangeable NH4+ and the resin adsorption of N was studied in a paddy soil, typical for Zhejiang Province, China. Oxalic and citric acids under low pH conditions, in combination with proton secretion, favored the mobilization of NH4+ ions and increased resin adsorption of N. The release of non-exchangeable NH4+ was associated with less formation of iron oxides. These could coat clay minerals and thus hinder the diffusion of NH4+ ions out of the interlayer. Protons enhanced the release of NH4+, and then they could enter the wedge zones of the clay minerals and displace non-exchangeable NH4+ ions.

  4. Autotrophic nitrogen removal process in a potable water treatment biofilter that simultaneously removes Mn and NH4(+)-N. (United States)

    Cai, Yan'an; Li, Dong; Liang, Yuhai; Zeng, Huiping; Zhang, Jie


    Ammonia (NH4(+)-N) removal pathways were investigated in a potable water treatment biofilter that simultaneously removes manganese (Mn) and NH4(+)-N. The results indicated a significant loss of nitrogen in the biofilter. Both the completely autotrophic nitrogen removal over nitrite (CANON) process and nitrification were more likely to contribute to NH4(+)-N removal. Moreover, the model calculation results demonstrated that the CANON process contributed significantly to the removal of NH4(+)-N. For influent NH4(+)-N levels of 1.030 and 1.749mg/L, the CANON process contribution was about 48.5% and 46.6%, respectively. The most important finding was that anaerobic ammonia oxidation (ANAMMOX) bacteria were detectable in the biofilter. It is interesting that the CANON process was effective even for such low NH4(+)-N concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Synthesis of analogues of the Des-Phe-NH2 C-terminal hexapeptide of cholecystokinin showing gastrin antagonist activity. (United States)

    Laur, J; Rodriguez, M; Aumelas, A; Bali, J P; Martinez, J


    Four analogues of Z-CCK-27-32-NH2, Z-Tyr(SO3-)-Met-Gly-Trp-Met-Asp-NH2, a cholecystokinin receptor antagonist have been synthesized by solution methodology. In these analogues, Z-Tyr(SO3-)-Nle-Gly-Trp-Met-Asp-NH2 16, Z-Tyr(SO3-)-Nle-Gly-Trp-Nle-Asp-NH2 17, BOC-Tyr(SO3-)-Met-Gly-Trp-Met-Asp-NH2 24 and Boc-Tyr(SO3-)-Met-Gly-Trp-Nle-Asp-NH2 25 methionyl residues were replaced by norleucyl residues. Preliminary biological activity on gastrin-induced acid secretion, in rat, are reported. These derivatives proved to antagonize the action of gastrin, with ED 50 of between 0.5 and 3 mg/kg.

  6. Mechanistic investigation of the NH-sulfoximination of sulfide. Evidence for λ(6)-sulfanenitrile intermediates. (United States)

    Lohier, Jean-François; Glachet, Thomas; Marzag, Hamid; Gaumont, Annie-Claude; Reboul, Vincent


    We report a new procedure for the preparation of NH-sulfoximines from sulfides using PIDA as an oxidant and ammonium carbamate as the ammonia source. Excellent yields were obtained with a wide range of sulfides. The formation of acetoxy- and methoxy-λ(6)-sulfanenitrile as intermediates was proposed, both of which were converted to the NH-sulfoximine by the action of the solvent. The structure of these intermediates was confirmed by (1)H, (13)C and (15)N NMR and HRMS analysis.

  7. Modelling of catalytic oxidation of NH3 and reduction of NO on limestone during sulphur capture

    DEFF Research Database (Denmark)

    Kiil, Søren; Bhatia, Suresh K.; Dam-Johansen, Kim


    for the catalytic chemistry of NH3 during simultaneous sulphur capture on a Stevns Chalk particle. The reduction of NO by NH3 over CaSO4 (which is the product of the reaction between SO2, O2 and limestone) was found to be important because this reaction could explain the change in selectivity with increased solid...... conversion observed experimentally. Simulations also suggested that it may be advantageous with respect to the emission of NO to use smallinstead of big limestone particles for desulphurisation in fluidised bed combustors due to the ways different sized particles capture SO2....

  8. Deuterium isotope effects on 13C chemical shifts of negatively charged NH.N systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Pietrzak, Mariusz; Grech, Eugeniusz


    Deuterium isotope effects on 13C chemical shifts are investigated in anions of 1,8-bis(4-toluenesulphonamido)naphthalenes together with N,N-(naphthalene-1,8-diyl)bis(2,2,2-trifluoracetamide) all with bis(1,8-dimethylamino)napthaleneH+ as counter ion. These compounds represent both “static......” and equilibrium cases. NMR assignments of the former have been revised. The NH proton is deuteriated. The isotope effects on 13C chemical shifts are rather unusual in these strongly hydrogen bonded systems between a NH and a negatively charged nitrogen atom. The formal four-bond effects are found to be negative...

  9. Finding the Next Deep-Ultraviolet Nonlinear Optical Material: NH4B4O6F. (United States)

    Shi, Guoqiang; Wang, Ying; Zhang, Fangfang; Zhang, Bingbing; Yang, Zhihua; Hou, Xueling; Pan, Shilie; Poeppelmeier, Kenneth R


    Nonlinear optical materials are essential for the development of solid-state lasers. KBe2BO3F2 (KBBF) is a unique nonlinear optical material for generation of deep-ultraviolet coherent light; however, its industrial application is limited. Here, we report a new material NH4B4O6F, which exhibits a wide deep-ultraviolet transparent range and suitable birefringence that enables frequency doubling below 200 nm. NH4B4O6F possesses large nonlinear coefficients about 2.5 times that of KBBF. In addition, it is easy to grow bulk crystals and does not contain toxic elements.

  10. Ab-initio density functional theory study of a WO3 NH3-sensing mechanism

    Institute of Scientific and Technical Information of China (English)

    Hu Ming; Zhang Jie; Wang Wei-Dan; Qin Yu-Xiang


    WO3 bulk and various surfaces are studied by an ab-initio density functional theory technique.The band structures and electronic density states of WO3 bulk are investigated.The surface energies of different WO3 surfaces are compared and then the(002)surface with minimum energy is computed for its NH3 sensing mechanism which explains the results in the experiments.Three adsorption sites are considered.According to the comparisons of the energy and the charge change between before and after adsorption in the optimal adsorption site O1c,the NH3 sensing mechanism is obtained.

  11. Electronic properties of NH4-adsorbed graphene nanoribbon as a promising candidate for a gas sensor (United States)

    Harada, Naoki; Sato, Shintaro


    The electronic properties of NH4-adsorbed N = 7 armchair graphene nanoribbons (AGNRs) were theoretically investigated using self-consistent atomistic simulations to explore the feasibility of AGNRs as a gas sensing material. Whereas a pristine AGNR has a finite band gap and is an intrinsic semiconductor, an NH4-adsorbed AGNR exhibits heavily doped n-type properties similar to a graphene sheet with the molecules adsorbed. The electric characteristics of a back-gated AGNR gas sensor were also simulated and the drain current changed exponentially with increasing number of adsorbed molecules. We may conclude that an AGNR is promising as a highly sensitive gas-sensing material with large outputs.

  12. High-resolution absorption measurements of NH3 at high temperatures: 2100–5500 cm−1

    DEFF Research Database (Denmark)

    Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan


    High-resolution absorption spectra of NH3 in the region 2100–5500 cm−1 at 1027 °C and approximately atmospheric pressure (1045±3 mbar) are measured. An NH3 concentration of 10% in volume fraction is used in the measurements. Spectra are recorded in a high-temperature gas-flow cell using a Fourier...... Transform Infrared (FTIR) spectrometer at a nominal resolution of 0.09 cm−1. The spectra are analysed by comparison to a variational line list, BYTe, and experimental energy levels determined using the MARVEL procedure. 2308 lines have been assigned to 45 different bands, of which 1755 and 15 have been...

  13. High-resolution absorption measurements of NH3 at high temperatures: 500–2100cm−1

    DEFF Research Database (Denmark)

    Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan


    High-resolution absorption spectra of NH3 in the region 500–2100 cm -1 at temperatures up to1027 1C and approximately atmospheric pressure (1013±20 mbar) are measured. NH3 concentrations of 1000 ppm,0.5% and 1% in volume fraction were used in the measurements. Spectra are recorded in high...... temperature gas flow cells using a FourierTransform Infrared (FTIR) spectrometer at a nominal resolution of 0.09cm-1. Measurements at 22.7 °C are compared to high-resolution cross sections available from thePacific Northwest National Laboratory (PNNL). The higher temperature spectra are analysed by comparison...

  14. NH3 (10-00) in the pre-stellar core L1544 (United States)

    Caselli, P.; Bizzocchi, L.; Keto, E.; Sipilä, O.; Tafalla, M.; Pagani, L.; Kristensen, L. E.; van der Tak, F. F. S.; Walmsley, C. M.; Codella, C.; Nisini, B.; Aikawa, Y.; Faure, A.; van Dishoeck, E. F.


    Pre-stellar cores represent the initial conditions in the process of star and planet formation, therefore it is important to study their physical and chemical structure. Because of their volatility, nitrogen-bearing molecules are key to study the dense and cold gas present in pre-stellar cores. The NH3 rotational transition detected with Herschel-HIFI provides a unique combination of sensitivity and spectral resolution to further investigate physical and chemical processes in pre-stellar cores. Here we present the velocity-resolved Herschel-HIFI observations of the ortho-NH3(10 - 00) line at 572 GHz and study the abundance profile of ammonia across the pre-stellar core L1544 to test current theories of its physical and chemical structure. Recently calculated collisional coefficients have been included in our non-LTE radiative transfer code to reproduce Herschel observations. A gas-grain chemical model, including spin-state chemistry and applied to the (static) physical structure of L1544 is also used to infer the abundance profile of ortho-NH3. The hyperfine structure of ortho-NH3(10 - 00) is resolved for the first time in space. All the hyperfine components are strongly self-absorbed. The profile can be reproduced if the core is contracting in quasi-equilibrium, consistent with previous work, and if the NH3 abundance is slightly rising toward the core centre, as deduced from previous interferometric observations of para-NH3(1, 1). The chemical model overestimates the NH3 abundance at radii between ≃4000 and 15 000 AU by about two orders of magnitude and underestimates the abundance toward the core centre by more than one order of magnitude. Our observations show that chemical models applied to static clouds have problems in reproducing NH3 observations. Based on observations carried out with Herschel, an ESA space observatory with science instruments provided by a European-led Principal Investigator consortium and with important participation from NASA.

  15. Surface tension measurements of aqueous ammonium chloride (NH4Cl) in air (United States)

    Lowry, S. A.; Mccay, M. H.; Mccay, T. D.; Gray, P. A.


    Aqueous NH4Cl's solidification is often used to model metal alloy solidification processes. The present determinations of the magnitude of the variation of aqueous NH4Cl's surface tension as a function of both temperature and solutal concentration were conducted at 3, 24, and 40 C over the 72-100 wt pct water solutal range. In general, the surface tension increases 0.31 dyn/cm per percent decrease in wt pct of water, and decreases 0.13 dyn/cm for each increase in deg C. Attention is given to the experimental apparatus employed.

  16. Gas phase detection of the NH-P hydrogen bond and importance of secondary interactions

    DEFF Research Database (Denmark)

    Møller, Kristian Holten; Hansen, Anne Schou; Kjærgaard, Henrik Grum


    We have observed the NH···P hydrogen bond in a gas phase complex. The bond is identified in the dimethylamine-trimethylphosphine complex by a red shift of the fundamental NH-stretching frequency observed using Fourier transform infrared spectroscopy (FT-IR). On the basis of the measured NH-stretc......3LYP-D3BJ, CAM-B3LYP, and ωB97X-D, as well as MP2, show comparable contributions from the hydrogen bond and the secondary interactions and are close to DF-LCCSD(T)-F12a results....

  17. Emission and distribution of NH3 and NOx in China.%中国大气NH3和NOx排放的时空分布特征

    Institute of Scientific and Technical Information of China (English)

    李新艳; 李恒鹏


    根据我国不同氨源的数量、燃料消费量和相应的氨与氮氧化物排放因子,计算了我国大陆地区1995~2004年历年的氨(NH3)排放量与1985~2005年历年的氮氧化物(NOx)排放量,在此基础上模拟了2006~2010年的NOx排放量,并分析了NH3和NOx排放强度的空间分布.结果表明:2004年,我国NH3排放量为12.0Tg,比1995年的10.6Tg增加了大约13.2%;2004年的NOx排放量为20.6Tg,比1995年的12.2Tg增加了大约68.9%,比1985年的6.2Tg增加了大约2.3倍.在1996年以前,我国NH3和NOx的排放量基本相当,但是此后NH3的年排放量在经历了1997~1999年的下降之后,变化比较平稳,而NOx的排放量自2000年之后呈逐年迅速增加的趋势.2004年全国NH3的排放总量中,畜禽排泄、氮肥施用、人类粪便、氮肥与合成氨生产的贡献率分别为69.2%、15.2%、13.9%和1.9%;2004年全国NOx的排放总量中,由于受到我国能源消费结构的制约,煤炭来源的NOx占到了排放总量的77.4%.NH3和NOx的排放强度都具有明显的空间差异,表现在中东部地区的排放强度明显高于西部地区,这与中东部地区人口多、能源消费量大以及畜禽养殖数量大有关.%Annual emission of ammonia and Noχ in the inland of China were calculated based on the numbers of livestock, poultry, human beings, the quantity of fertilizer application and production and fuel consumption. The temporal and spatial distribution of emission intensity of NH3 and Noχ were also analyzed. NH3 emission in China changed slowly from 10.6Tg in 1995 to 12.0Tg in 2004, while Noχ emission increased quickly from 12.2Tg in 1995 to 20.6Tg in 2004, with a mean increase rate of 68.9%. In 2004, emission from livestock, nitrogen fertilizer application, human beings and fertilizer production accounted for 69.2%, 15.2%, 13.9% and 1.9% of the total NH3 emission, respectively. Emission from coal combustion accounted for about 77.4% of the total Noχ emission

  18. Photovoltaic properties of Cu-doped CH3NH3PbI3 with perovskite structure (United States)

    Shirahata, Yasuhiro; Oku, Takeo


    Photovoltaic properties of copper (Cu)-doped perovskite (CH3NH3PbCuxI3+x) photovoltaic devices with different Cu content were investigated. The CH3NH3PbCuxI3+x films were polycrystalline with a tetragonal system, and their lattice constants and crystallite size varied with Cu doping. Compared to conversion efficiencies of non-doped CH3NH3PbI3 photovoltaic device, those of CH3NH3PbCuxI3+x photovoltaic devises increased. The improvement of photovoltaic properties was attributed to partial substitution of Cu at the Pb sites.

  19. Giant-Planet Chemistry: Ammonium Hydrosulfide (NH4SH), Its IR Spectra and Thermal and Radiolytic Stabilities (United States)

    Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.


    Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10-160 K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing ions. Crystalline NH4SH was amorphized during irradiation at all temperatures studied with the rate being the fastest at the lowest temperatures. Irradiation of amorphous NH4SH at approximately 10-75 K showed that 60-80% of the NH4 + remained when equilibrium was reached, and that NH4SH destruction rates were relatively constant within this temperature range. Irradiations at higher temperatures produced different dose dependence and were accompanied by pressure outbursts that, in some cases, fractured the ice. The thermal stability of irradiated NH4SH was found to be greater than that of unirradiated NH4SH, suggesting that an irradiated giant-planet cloud precipitate can exist at temperatures and altitudes not previously considered.

  20. Giant-Planet Chemistry: Ammonium Hydrosulfide (NH4SH), Its IR Spectra and Thermal and Radiolytic Stabilities (United States)

    Loeffler, Mark J.; Hudson, Reggie L.; Chanover, Nancy J.; Simon, Amy A.


    Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10-160 K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing ions. Crystalline NH4SH was amorphized during irradiation at all temperatures studied with the rate being the fastest at the lowest temperatures. Irradiation of amorphous NH4SH at approximately 10-75 K showed that 60-80% of the NH4 + remained when equilibrium was reached, and that NH4SH destruction rates were relatively constant within this temperature range. Irradiations at higher temperatures produced different dose dependence and were accompanied by pressure outbursts that, in some cases, fractured the ice. The thermal stability of irradiated NH4SH was found to be greater than that of unirradiated NH4SH, suggesting that an irradiated giant-planet cloud precipitate can exist at temperatures and altitudes not previously considered.

  1. Nickel(Ⅱ) Complexes Bearing NH2CH2CH2CH2NH2 and o-C6H4(NH2)2 Ligands:Synthesis, Structures and Their Ethylene Polymerization Behavior

    Institute of Scientific and Technical Information of China (English)

    LU Xiaoming; WANG Zhen; LIU Man


    Two nickel complexes [Ni(NH2CH2CH2CH2NH2)3]Cl2 (1) and [Ni(C6H4N2H4)2Cl2] (2) have been obtained and characterized by IR and single crystal X-ray diffraction analysis. In complex 1, the nickel atom was in a chiral pseudo-octahedral [NiN6] geometry environment, which was coordinated by three 1,3-propylenediamine to form three six-membered rings. However in complex 2, besides connected with two o-phenylenediarnine through four Ni-N bonds to form two five-membered rings, the nickel center was coordinated by two Cl to form trans-Ni-Cl2, which was different from general reported diimine nickel complexes. Activated with MAO, MMAO or Et2AlCl, these nickel complexes exhibited considerable good catalytic activity [up to 3.59×106 g·mol-1·h1for complex 2] for ethylene polymerization with main products as dimers or trimers of ethylene.

  2. Reinforcing graphene oxide/cement composite with NH$_2$ functionalizing group

    Indian Academy of Sciences (India)



    In this study, pure and NH$_2$-functionalized graphene oxide (GO) nanosheets have been added to the cement mortar with different weight percents (0.05, 0.10, 0.15, 0.20 and 0.25 wt%). In addition, the effects of functionalizing GO on the microstructure and mechanical properties (flexural/compressive strengths) of cement composite have been investigated for the first time. Scanning electron microscopy (SEM) images showed that GO filledthe pores and well dispersed in concrete matrix, whereas exceeding GO additive from 0.10 wt% caused the formation of agglomerates and microcracks. In addition, mercury intrusion porosimetry confirmed the significant effects of GO and functionalizing groups on filling the pores. NH2-functionalizing helped to improve the cohesion between GO nanosheets and cement composite. Compressive strengths increased from 39 MPa for the sample without GO to54.23 MPa for the cement composites containing 0.10 wt% of NH$_2$-functionalized GO. Moreover, the flexural strength increased to 23.4 and 38.4% by compositing the cement paste with 0.10 wt% of pure and NH$_2$-functionalized GO, compared to the sample without GO, respectively. It was shown that functionalizing considerably enhanced the mechanical properties of GO/cement composite due to the interfacial strength between calcium silicatehydrates (C-S-H) gel and functionalized GO nanosheets as observed in SEM images. The morphological results were in good agreement with the trend obtained in mechanical properties of GO/cement composites.

  3. Direct observation of intrinsic twin domains in tetragonal CH3NH3PbI3 (United States)

    Rothmann, Mathias Uller; Li, Wei; Zhu, Ye; Bach, Udo; Spiccia, Leone; Etheridge, Joanne; Cheng, Yi-Bing


    Organic–inorganic hybrid perovskites are exciting candidates for next-generation solar cells, with CH3NH3PbI3 being one of the most widely studied. While there have been intense efforts to fabricate and optimize photovoltaic devices using CH3NH3PbI3, critical questions remain regarding the crystal structure that governs its unique properties of the hybrid perovskite material. Here we report unambiguous evidence for crystallographic twin domains in tetragonal CH3NH3PbI3, observed using low-dose transmission electron microscopy and selected area electron diffraction. The domains are around 100–300 nm wide, which disappear/reappear above/below the tetragonal-to-cubic phase transition temperature (approximate 57 °C) in a reversible process that often ‘memorizes' the scale and orientation of the domains. Since these domains exist within the operational temperature range of solar cells, and have dimensions comparable to the thickness of typical CH3NH3PbI3 films in the solar cells, understanding the twin geometry and orientation is essential for further improving perovskite solar cells. PMID:28230064

  4. Blueshift and intramolecular tunneling of NH3 umbrella mode in 4He n clusters. (United States)

    Viel, Alexandra; Whaley, K Birgitta; Wheatley, Richard J


    We present diffusion Monte Carlo calculations of the ground and first excited vibrational states of NH(3) (4)He(n) for nblueshift of the umbrella mode frequency and a reduction of the tunneling splittings in ground and first excited vibrational states of the molecule. These basic features are found to result regardless of whether dynamical approximations or exact calculations are employed.

  5. Crown Ether Complexes with H3O+ and NH4+: Proton Localization and Proton Bridge Formation

    NARCIS (Netherlands)

    Hurtado, P.; Gamez, F.; Hamad, S.; Martinez-Haya, B.; Steill, J. D.; Oomens, J.


    The complexes formed by crown ethers with hydronium and ammonium cations are of key relevance for the understanding of their supramolecular behavior in protic solvents. In this work, the complexes of the 15-crown-5 (15c5) and 18-crown-6 (18c6) ethers with H3O+ and NH4+ and their deuterated variants

  6. Descriptor‐Based Analysis Applied to HCN Synthesis from NH3 and CH4

    DEFF Research Database (Denmark)

    Grabow, Lars C.; Studt, Felix; Abild‐Pedersen, Frank


    A trendy volcano: By the example of HCN synthesis from NH3 and CH4, it is demonstrated how scaling relations for intermediates and transition states provide a basis for the prediction of trends in heterogeneous catalysis (see logarithmic turnover frequency, TOF). These trends include not only the...

  7. Thermal Transformation of NH4-Clinoptilolite to Mullite and Silica Polymorphs

    Directory of Open Access Journals (Sweden)

    Antonio Brundu


    Full Text Available Clinoptilolite is a natural zeolite used for the abatement of ammonium in the treatment of urban wastewater. By considering that mullite was obtained through thermal treatment of NH4-exchanged synthetic zeolites, this work aimed to evaluate if this phase can be obtained from NH4-clinoptilolite. A material containing about 90 wt % of clinoptilolite, prepared using a Sardinian zeolite-rich rock, was NH4-exchanged and subjected to treatments up to 1200 °C. After dehydration, de-ammoniation, and dehydroxylation processes, the clinoptilolite structure collapsed at 600 °C. An association of mullite, silica polymorphs, and glass, whitish in color, was obtained for treatments between 1000 and 1200 °C. The higher degree of crystallinity was reached after a 32 h heating at 1100 °C: mullite 22 wt %, cristobalite 59 wt %, tridymite 10 wt %, glass 9 wt %. It is possible to speed up the kinetics of the transformation by increasing the temperature to 1200 °C, obtaining the same amount of mullite in 2 h, but increasing the residual amorphous fraction (16 wt %. These results indicate that NH4-clinoptilolite could represent a raw material of potential interest in the ceramic field, in particular in the production of acid refractory, opening scenarios for a possible reuse of clinoptilolite-based exchangers employed in ammonium decontamination.

  8. NH4+ secretion in the avian colon

    DEFF Research Database (Denmark)

    Holtug, Klavs; Laverty, Gary; Árnason, Sighvatur S.


      Experiments were designed to characterize an active, electrogenic transport of NH(4)(+) ions across the colonic epithelium of the domestic fowl (Gallus gallus). Colonic segments were isolated and stripped of underlying muscle. The mucosal epithelia were mounted in Ussing chambers and voltage......-clamped to measure the short-circuit currents (I(SC)) associated with transport. Bilateral addition of NH(4)(+) caused a dose-dependent outward current (negative I(SC)), with a Km of 34+/-8 mM and a maximal current response of 311+/-47 microA cm(-2) (12+/-2 microEq cm(-2) h(-1)). A similar effect was seen...... with unilateral addition of NH(4)(+) to the serosal (s) side, but not with mucosal (m) addition. Pre-treatment with 10(-4) M amiloride exposed a net outward (negative) I(SC), and serosal NH(4)(+) addition further increased this outward current with a Km of 53+/-24 mM. Decreasing the bath pH from 7.3 to 6.0 did...

  9. Calculation of optimal parameters of an NH3-CO2 lidar

    NARCIS (Netherlands)

    Vasil'ev, BI; Mannoun, OM


    The basic parameters (range, signal-to-noise ratio, and sensitivity) of a lidar using NH3 and CO2 lasers are calculated. The principle of lidar operation is based on the differential absorption recording. Absorption spectra of all known Freons are considered in the spectral range 9-13.5 mu m and opt

  10. Chemical deactivation of Cu-SSZ-13 ammonia selective catalytic reduction (NH3-SCR) systems

    NARCIS (Netherlands)

    Lezcano-Gonzalez, I.; Deka, U.; van der Bij, H. E.; Paalanen, P.; Arstad, B.; Weckhuysen, B. M.; Beale, A. M.


    The chemical deactivation of Cu-SSZ-13 Ammonia Selective Catalytic Reduction (NH3-SCR) catalysts by Pt, Zn, Ca and P has been systematically investigated using a range of analytical techniques in order to study the influence on both the zeolitic framework and the active Cu2+ ions. The results obtain

  11. Measurement of the dry deposition flux of NH3 on to coniferous forest

    NARCIS (Netherlands)

    Duyzer, J.H.; Verhagen, H.L.M.; Weststrate, J.H.; Bosveld, F.C.


    The dry deposition flux of NH3 to coniferous forest was determined by the micrometeorological gradient method using a 36m high tower. Aerodynamic characteristics of the site were studied, using a second tower erected in the forest 100m from the first. Fluxes and gradients of heat and momentum measur

  12. Growth response of cottonwood roots to varied NH4:NO3 ratios in enriched patches (United States)

    Walter T.M. Woolfolk; Alexander L. Friend


    Maximization of short-rotation forest plantation yields requires frequent applications of nutriends, especially nitrogen(N). Whole-plant growth is known to be sensitive to teh proportion of ammonium to nitrate (NH4:NO3). However, the extent to which N form affects root growth, branching and morphology is poorly understood...

  13. DFT investigation of NH3 gas interactions on TeO2 nanostructures

    Institute of Scientific and Technical Information of China (English)

    V. Nagarajan; R. Chandiramouli


    The structural, electronic and adsorption properties of NH3 on pristine, Sn and F substituted TeO2 na-nostructures were investigated using density functional theory with B3LYP/LanL2DZ basis set. The electronic properties of pristine, Sn and F incorporated TeO2 nanostructures were explained with ioni-zation potential, HOMO–LUMO gap and electron affinity. The dipole moment and point group of rutile TeO2 nanostructures were also reported. The structural stability of pristine, Sn and F substituted TeO2 nanostructures were investigated in terms of formation energy. The adsorption properties of NH3 on TeO2 were studied and the proper adsorption sites of NH3 on TeO2 materials were identified and dis-cussed with the suitable parameters such as adsorption energy, HOMO–LUMO gap, Mulliken population analysis and average energy gap variation. The results show that the substitution of fluorine in TeO2 nanostructure enhances NH3 adsorption properties in mixed gas environment.

  14. Meteorite Impact-Induced Rapid NH3 Production on Early Earth: Ab Initio Molecular Dynamics Simulation (United States)

    Shimamura, Kohei; Shimojo, Fuyuki; Nakano, Aiichiro; Tanaka, Shigenori


    NH3 is an essential molecule as a nitrogen source for prebiotic amino acid syntheses such as the Strecker reaction. Previous shock experiments demonstrated that meteorite impacts on ancient oceans would have provided a considerable amount of NH3 from atmospheric N2 and oceanic H2O through reduction by meteoritic iron. However, specific production mechanisms remain unclear, and impact velocities employed in the experiments were substantially lower than typical impact velocities of meteorites on the early Earth. Here, to investigate the issues from the atomistic viewpoint, we performed multi-scale shock technique-based ab initio molecular dynamics simulations. The results revealed a rapid production of NH3 within several picoseconds after the shock, indicating that shocks with greater impact velocities would provide further increase in the yield of NH3. Meanwhile, the picosecond-order production makes one expect that the important nitrogen source precursors of amino acids were obtained immediately after the impact. It was also observed that the reduction of N2 proceeded according to an associative mechanism, rather than a dissociative mechanism as in the Haber-Bosch process.

  15. 76 FR 60599 - Boston & Maine Corporation-Abandonment Exemptions-in Rockingham, NH; Springfield Terminal Railway... (United States)


    .... The Line traverses United States Postal Service Zip Codes 03801, 03840, 03842, 03862, and 03870. Applicants have certified that: (1) No local traffic has moved over the line for at least 2 years; (2) there... railroad ] known as the Hampton Branch in Rockingham County, NH. The rail line extends from milepost...

  16. Intrinsic defects and dopants in LiNH2 : a first-principles study

    NARCIS (Netherlands)

    Hazrati, E.; Brocks, G.; Buurman, B.; de Groot, R. A.; de Wijs, G. A.


    The lithium amide (LiNH2) + lithium hydride (LiH) system is one of the most attractive light-weight materials options for hydrogen storage. Its dehydrogenation involves mass transport in the bulk (amide) crystal through lattice defects. We present a first-principles study of native point defects and

  17. Calculation of optimal parameters of an NH3-CO2 lidar

    NARCIS (Netherlands)

    Vasil'ev, BI; Mannoun, OM

    The basic parameters (range, signal-to-noise ratio, and sensitivity) of a lidar using NH3 and CO2 lasers are calculated. The principle of lidar operation is based on the differential absorption recording. Absorption spectra of all known Freons are considered in the spectral range 9-13.5 mu m and

  18. The mechanism of NH3 and SO2 uptake by leaves and its physiological effects.

    NARCIS (Netherlands)

    Hove, van L.W.A.


    The relation between uptake of atmospheric ammonia (NH 3 ) and sulphur dioxide (SO 2 ) by individual leaves, photosynthesis and stomatal conductance was examined. The experiments were carried out with bean plants ( Phaseolus vulgari

  19. NH$_3$(3,3) and CH$_3$OH near Supernova Remnants: GBT and VLA Observations

    CERN Document Server

    McEwen, Bridget; Sjouwerman, Loránt


    We report on Green Bank Telescope 23.87 GHz NH$_3$(3,3), emission observations in five supernova remnants interacting with molecular clouds (G1.4$-$0.1, IC443, W44, W51C, and G5.7$-$0.0). The observations show a clumpy gas density distribution, and in most cases the narrow line widths of $\\sim3-4$\\,km\\,s$^{-1}$ are suggestive of maser emission. Very Large Array observations reveal 36~GHz and/or 44~GHz CH$_3$OH, maser emission in a majority (72\\%) of the NH$_3$, peak positions towards three of these SNRs. This good positional correlation is in agreement with the high densities required for the excitation of each line. Through these observations we have shown that CH$_3$OH, and NH$_3$, maser emission can be used as indicators of high density clumps of gas shocked by supernova remnants, and provide density estimates thereof. Modeling of the optical depth of the NH$_3$(3,3) emission is compared to that of CH$_3$OH, constraining the densities of the clumps to a typical density of the order of $10^5$~cm$^{-3}$ for ...

  20. Identification of solar vibration-rotation lines of NH and the solar nitrogen abundance

    NARCIS (Netherlands)

    Grevesse, N.; Lambert, D.L.; Sauval, A.J.; Dishoeck, van E.F.; Farmer, C.B.; Norton, R.H.


    High resolution solar spectra obtained from the ATMOS Fourier Transform Spectrometer (Spacelab 3 flight on April 29 - May 6, 1985) made it possible to detect for the first time vibration-rotation lines of NH from the X3 Sigma(-) state near 3 microns. Using recent theoretical results for the transiti

  1. NH4HCO3 gas-generating liposomal nanoparticle for photoacoustic imaging in breast cancer

    Directory of Open Access Journals (Sweden)

    Xia J


    Full Text Available Jizhu Xia, Gang Feng, Xiaorong Xia, Lan Hao, Zhigang Wang Chongqing Key Laboratory of Ultrasound Molecular Imaging, Department of Ultrasound, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China Abstract: In this study, we have developed a biodegradable nanomaterial for photoacoustic imaging (PAI. Its biodegradation products can be fully eliminated from a living organism. It is a gas-generating nanoparticle of liposome-encapsulating ammonium bicarbonate (NH4HCO3 solution, which is safe, effective, inexpensive, and free of side effects. When lasers irradiate these nanoparticles, NH4HCO3 decomposes to produce CO2, which can absorb much of the light energy under laser irradiation with a specific wavelength, and then expand under heat to generate a thermal acoustic wave. An acoustic detector can detect this wave and show it as a photoacoustic signal on a display screen. The intensity of the photoacoustic signal is enhanced corresponding to an increase in time, concentration, and temperature. During in vivo testing, nanoparticles were injected into tumor-bearing nude mice through the caudal vein, and photoacoustic signals were detected from the tumor, reaching a peak in 4 h, and then gradually disappearing. There was no damage to the skin or subcutaneous tissue from laser radiation. Our developed gas-generating nanomaterial, NH4HCO3 nanomaterial, is feasible, effective, safe, and inexpensive. Therefore, it is a promising material to be used in clinical PAI. Keywords: Photoacoustic tomography, CO2, NH4HCO3, contrast agent, cancer

  2. Synthesis and Characterization of Th2N2(NH) Isomorphous to Th2N3

    Energy Technology Data Exchange (ETDEWEB)

    Silva, G W Chinthaka M [ORNL; Yeamans, Charles B. [University of California, Berkeley; Hunn, John D [ORNL; Sattelberger, Alfred P [Argonne National Laboratory (ANL); Czerwinski, Ken R. [University of Nevada, Las Vegas; Weck, Dr. Phil F [University of Nevada, Las Vegas


    Using a new, low-temperature, fluoride-based process, thorium nitride imide of the chemical formula Th{sub 2}N{sub 2}(NH) was synthesized from thorium dioxide via an ammonium thorium fluoride intermediate. The resulting product phase was characterized by powder X-ray diffraction (XRD) analysis and was found to be crystallographically similar to Th{sub 2}N{sub 3}. Its unit cell was hexagonal with a space group of P3m{bar 1} and lattice parameters of a = b = 3.886(1) and c = 6.185(2) {angstrom}. The presence of -NH in the nitride phase was verified by Fourier transform infrared spectroscopy (FTIR). Total energy calculations performed using all-electron scalar relativistic density functional theory (DFT) showed that the hydrogen atom in the Th{sub 2}N{sub 2}(NH) prefers to bond with nitrogen atoms occupying 1a Wyckoff positions of the unit cell. Lattice fringe disruptions observed in nanoparticle areas of the nitride species by high-resolution transmission electron microscopic (HRTEM) images also displayed some evidence for the presence of -NH group. As ThO{sub 2} was identified as an impurity, possible reaction mechanisms involving its formation are discussed.

  3. A receptor incorporating OH, NH and CH binding motifs for a fluoride selective chemosensor. (United States)

    Xu, Liang; Li, Yongjun; Yu, Yanwen; Liu, Taifeng; Cheng, Songhua; Liu, Huibiao; Li, Yuliang


    An anion receptor combined different types of hydrogen bond donors such as OH, NH and CH groups has been synthesized. By rotation of the sub methyl group, this receptor showed evident (1)H NMR response to both fluoride and sulfate, while colorimetric and fluorescent responses were only observed in the presence of fluoride.

  4. Diagnostic NH and OH Vibrations for Oxazolone and Diketopiperazine Structures: b2 from Protonated Triglycine (United States)

    Wang, Da; Gulyuz, Kerim; Stedwell, Corey N.; Polfer, Nick C.


    We present infrared multiple photon dissociation (IRMPD) spectra in the hydrogen stretching region of the simplest b fragment, b2 from protonated triglycine, contrasted to that of protonated cyclo(Gly-Gly). Both spectra confirm the presence of intense, diagnostic vibrations linked to the site of proton attachment. Protonated cyclo(Gly-Gly) serves as a reference spectrum for the diketopiperazine structure, showing a diagnostic O-H+ stretch of the protonated carbonyl group at 3585 cm-1. Conversely, b2 from protonated triglycine exhibits a strong band at 3345 cm-1, associated with the N-H stretching mode of the protonated oxazolone ring structure. Other weaker N-H stretches can also be discerned, such as the amino NH2 and amide NH bands. These results demonstrate the usefulness of the hydrogen stretching region, and hence benchtop optical parametric oscillator/amplifier (OPO/A) set-ups, in making structural assignments of product ions in collision-induced dissociation (CID) of peptides.

  5. VizieR Online Data Catalog: 15NH2 amidogen radical rotational spectrum (M (United States)

    Margules, L.; Martin-Drumel, M. A.; Pirali, O.; Bailleux, S.; Wlodarczak, G.; Roy, P.; Roueff, E.; Gerin, M.


    Measured frequencies and residuals from the global fit of the Infrared, and submillimeter-wave data for 15NH2 and files used for SPFIT. Detailled explanations on SPFIT could be found at (4 data files).

  6. Rapid Microwave Synthesis, Characterization and Reactivity of Lithium Nitride Hydride, Li4NH

    Directory of Open Access Journals (Sweden)

    Nuria Tapia-Ruiz


    Full Text Available Lithium nitride hydride, Li4NH, was synthesised from lithium nitride and lithium hydride over minute timescales, using microwave synthesis methods in the solid state for the first time. The structure of the microwave-synthesised powders was confirmed by powder X-ray diffraction [tetragonal space group I41/a; a = 4.8864(1 Å, c = 9.9183(2 Å] and the nitride hydride reacts with moist air under ambient conditions to produce lithium hydroxide and subsequently lithium carbonate. Li4NH undergoes no dehydrogenation or decomposition [under Ar(g] below 773 K. A tetragonal–cubic phase transition, however, occurs for the compound at ca. 770 K. The new high temperature (HT phase adopts an anti-fluorite structure (space group Fm 3̅ m; a = 4.9462(3 Å with N3− and H− ions disordered on the 4a sites. Thermal treatment of Li4NH under nitrogen yields a stoichiometric mixture of lithium nitride and lithium imide (Li3N and Li2NH respectively.

  7. Parametrization of electron impact ionization cross sections for CO, CO2, NH3 and SO2 (United States)

    Srivastava, Santosh K.; Nguyen, Hung P.


    The electron impact ionization and dissociative ionization cross section data of CO, CO2, CH4, NH3, and SO2, measured in the laboratory, were parameterized utilizing an empirical formula based on the Born approximation. For this purpose an chi squared minimization technique was employed which provided an excellent fit to the experimental data.

  8. Comparative 4-E analysis of a bottoming pure NH3 and NH3-H2O mixture based power cycle for condenser waste heat recovery (United States)

    Khankari, Goutam; Karmakar, Sujit


    This paper proposes a comparative performance analysis based on 4-E (Energy, Exergy, Environment, and Economic) of a bottoming pure Ammonia (NH3) based Organic Rankine Cycle (ORC) and Ammonia-water (NH3-H2O) based Kalina Cycle System 11(KCS 11) for additional power generation through condenser waste heat recovery integrated with a conventional 500MWe Subcritical coal-fired thermal power plant. A typical high-ash Indian coal is used for the analysis. The flow-sheet computer programme `Cycle Tempo' is used to simulate both the cycles for thermodynamic performance analysis at different plant operating conditions. Thermodynamic analysis is done by varying different NH3 mass fraction in KCS11 and at different turbine inlet pressure in both ORC and KCS11. Results show that the optimum operating pressure of ORC and KCS11 with NH3 mass fraction of 0.90 are about 15 bar and 11.70 bar, respectively and more than 14 bar of operating pressure, the plant performance of ORC integrated power plant is higher than the KCS11 integrated power plant and the result is observed reverse below this pressure. The energy and exergy efficiencies of ORC cycle are higher than the KCS11 by about 0.903 % point and 16.605 % points, respectively under similar saturation vapour temperature at turbine inlet for both the cycles. Similarly, plant energy and exergy efficiencies of ORC based combined cycle power plant are increased by 0.460 % point and 0.420 % point, respectively over KCS11 based combined cycle power plant. Moreover, the reduction of CO2 emission in ORC based combined cycle is about 3.23 t/hr which is about 1.5 times higher than the KCS11 based combined cycle power plant. Exergy destruction of the evaporator in ORC decreases with increase in operating pressure due to decrease in temperature difference of heat exchanging fluids. Exergy destruction rate in the evaporator of ORC is higher than KCS11 when the operating pressure of ORC reduces below 14 bar. This happens due to variable

  9. Exports of dissolved ammonium (NH(4)(+)) during storm events across multiple catchments in a glaciated forested watershed. (United States)

    Inamdar, Shreeram


    Storm event exports of dissolved NH(4)(+) were explored for multiple events in the Point Peter Brook watershed (PPBW), a glaciated, forested watershed located in Western New York, USA. Investigations were performed across four catchments (1.6-696 ha) with varying topography and the extent of surface-saturated areas. While wetland and riparian waters were important sources of NH(4)(+) during non-storm periods, throughfall and litter leachate were the dominant contributors of NH(4)(+) during storm events. Ammonium concentrations in catchment discharge displayed a sinusoidal seasonal pattern with a maximum during early spring (March) and a minimum in late summer (August-September). Storm event concentrations of NH(4)(+) in streamflow were much greater than baseflow values and showed a consistent temporal pattern with an increase in concentrations on the hydrograph rising limb, a peak at or before the discharge peak, followed by a decline in concentrations. Storm event patterns of DON were similar to NH(4)(+) while the patterns of [Formula: see text]differed from NH(4)(+) for the summer and fall events. The storm event expression of NH(4)(+) was attributed to throughfall and throughfall-mediated leaching of the litter layer. The reactive behavior of NH(4)(+) precluded its use in an end member mixing model (EMMA) for predicting streamflow concentrations. While concentrations of NH(4)(+) in precipitation and streamflow were high for the spring events, exports of NH(4)(+) in streamflow were highest for the large and intense storm events. Baseflow NH(4)(+) concentrations increased with the percent wetland/saturated area in the catchment but the same trend did not hold for storm-event concentrations.

  10. Adsorption of fluoride to UiO-66-NH2 in water: Stability, kinetic, isotherm and thermodynamic studies. (United States)

    Lin, Kun-Yi Andrew; Liu, Yu-Ting; Chen, Shen-Yi


    To provide safe drinking water, fluoride in water must be removed and adsorption processes appear to be the most widely used method. Metal organic frameworks (MOFs) represent a new class of adsorbents that have been used in various adsorption applications. To study the adsorption mechanism of fluoride to MOFs in water and obtain related adsorption parameters, we synthesized a zirconium-based MOF with a primary amine group on its ligand, named UiO-66-NH2. The kinetics, adsorption isotherm and thermodynamics of fluoride adsorption to UiO-66-NH2 were investigated. The crystalline structure of UiO-66-NH2 remained intact and the local structure of zirconium in UiO-66-NH2 did not change significantly after being exposed to fluoride. The kinetics of the fluoride adsorption in UiO-66-NH2 could be well represented by the pseudo second order rate law. The enthalpy of the adsorption indicates that the F(-) adsorption to UiO-66-NH2 was classified as a physical adsorption. However, the comparison between the adsorption capacities of UiO-66-NH2 and UiO-66 suggests that the fluoride adsorption to UiO-66-NH2 might primarily involve a strong interaction between F(-) and the metal site. The fluoride adsorption capacity of UiO-66-NH2 was found to decrease when pH>7. While the presence of chloride/bromide ions did not noticeably change the adsorption capacity of UiO-66-NH2, the ionic surfactants slightly affected the adsorption capacity of UiO-66-NH2. These findings provide insights to further optimize the adsorption process for removal of fluoride using zirconium-based MOFs.

  11. In-situ and Real-time Monitoring of Mechanochemical Preparation of Li2Mg(NH2BH3)4 and Na2Mg(NH2BH3)4 and their Thermal Dehydrogenation. (United States)

    Biliskov, Nikola; Borgschulte, Andreas; Užarević, Krunoslav; Halasz, Ivan; Lukin, Stipe; Milošević, Sanja; Milanović, Igor; Grbović Novaković, Jasmina


    For the first time, in-situ monitoring of uninterrupted mechanochemical synthesis of two bimetallic amidoboranes,M2Mg(NH2BH3)4 (M = Li, Na), by means of Raman spectroscopy has been applied. This approach allowed real-time observation of key intermediate phases and a straightforward follow-up of the reaction course. Detailed analysis of time-dependent spectra revealed a two-step mechanism through MNH2BH3.NH3BH3 adducts as key intermediate phases which further reacted with MgH2, giving M2Mg(NH2BH3)4 as final products. The intermediates partially take a competitive pathway toward the oligomeric M(BH3NH2BH2NH2BH3) phases. The crystal structure of the novel bimetallic amidoborane Li2Mg(NH2BH3)4 was solved from high-resolution powder diffraction data and showed an analogous metal coordination as in Na2Mg(NH2BH3)4, but a significantly different crystal packing. Li2Mg(NH2BH3)4 thermally dehydrogenates releasing highly pure H2 in the amount of 7 wt% and at a lower temperature then its sodium analogue making it significantly more viable for practical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of Na+ impregnated activated carbon on the adsorption of NH4(+)-N from aqueous solution. (United States)

    Shi, Mo; Wang, Zhengfang; Zheng, Zheng


    Two kinds of activated carbons modified by Na+ impregnation after pre-treatments involving oxidation by nitric acid or acidification by hydrochloric acid (denoted as AC/N-Na and AC/HCl-Na, respectively), were used as adsorbents to remove NH4(+)-N. The surface features of samples were investigated by BET, SEM, XRD and FT-IR. The adsorption experiments were conducted in equilibrium and kinetic conditions. Influencing factors such as initial solution pH and initial concentration were investigated. A possible mechanism was proposed. Results showed that optimal NH4(+)-N removal efficiency was achieved at a neutral pH condition for the modified ACs. The Langmuir isotherm adsorption equation provided a better fit than other models for the equilibrium study. The adsorption kinetics followed both the pseudo second-order kinetics model and intra-particle kinetic model. Chemical surface analysis indicated that Na+ ions form ionic bonds with available surface functional groups created by pre-treatment, especially oxidation by nitric acid, thus increasing the removal efficiency of the modified ACs for NH4(+)-N. Na(+)-impregnated ACs had a higher removal capability in removing NH4(+)-N than unmodified AC, possibly resulting from higher numbers of surface functional groups and better intra-particle diffusion. The good fit of Langmuir isotherm adsorption to the data indicated the presence of monolayer NH4(+)-N adsorption on the active homogenous sites within the adsorbents. The applicability of pseudo second-order and intra-particle kinetic models revealed the complex nature of the adsorption mechanism. The intra-particle diffusion model revealed that the adsorption process consisted not only of surface adsorption but also intra-particle diffusion.

  13. Mesoscopic CH 3 NH 3 PbI 3 /TiO 2 Heterojunction Solar Cells

    KAUST Repository

    Etgar, Lioz


    We report for the first time on a hole conductor-free mesoscopic methylammonium lead iodide (CH 3NH 3PbI 3) perovskite/TiO 2 heterojunction solar cell, produced by deposition of perovskite nanoparticles from a solution of CH 3NH 3I and PbI 2 in γ-butyrolactone on a 400 nm thick film of TiO 2 (anatase) nanosheets exposing (001) facets. A gold film was evaporated on top of the CH 3NH 3PbI 3 as a back contact. Importantly, the CH 3NH 3PbI 3 nanoparticles assume here simultaneously the roles of both light harvester and hole conductor, rendering superfluous the use of an additional hole transporting material. The simple mesoscopic CH 3NH 3PbI 3/TiO 2 heterojunction solar cell shows impressive photovoltaic performance, with short-circuit photocurrent J sc= 16.1 mA/cm 2, open-circuit photovoltage V oc = 0.631 V, and a fill factor FF = 0.57, corresponding to a light to electric power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar light of 1000 W/m 2 intensity. At a lower light intensity of 100W/m 2, a PCE of 7.3% was measured. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost, high-efficiency solar cells. © 2012 American Chemical Society.

  14. Kinetics of sup 15 NH sub 4 sup + assimilation in Zea mays

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, J.R.; Ju, G.C.; Rich, P.J.; Rhodes, D. (EMBRAPA-Centro Nacional de Pesquisa de Hortalicas-CNPH, Brasilia-D.F. (Brazil) Purdue Univ., West Lafayette, IN (USA))


    Comparative studies of {sup 15}NH{sub 4}{sup +} assimilation were undertaken with a GDH1-null mutant of Zea mays and a related (but not strictly isogenic) GDH1-positive wild type from which this mutant was derived. The kinetics of {sup 15}NH{sub 4}{sup +} assimilation into free amino acids and total reduced nitrogen were monitored in both roots and shoots of 2-week-old seedlings supplied with 5 millimolar 99% ({sup 15}NH{sub 4}){sub 2}SO{sub 4} via the aerated root medium in hydroponic culture over a 24-h period. The GDH1-null mutant, with a 10- to 15-fold lower total root GDH activity in comparison to the wild type, was found to exhibit a 40 to 50% lower rate of {sup 15}NH{sub 4}{sup +} assimilation into total reduced nitrogen. The lower rates of {sup 15}NH{sub 4}{sup +} assimilation in the mutant was associated with lower rates of labeling of several free amino acids (including glutamate, glutamine-amino N, aspartate, asparagine-amino N, and alanine) in both roots and shoots of the mutant in comparison to the wild type. Qualitatively, these labeling kinetics appear consistent with a reduced flux of {sup 15}N via glutamate in the GDH1-null mutant. However, the responses of the two genotypes to the potent inhibitor of glutamine synthetase, methionine sulfoximine, and differences in morphology of the two genotypes (particularly a lower shoot:root ratio in the GDH1-null mutant) urge caution in concluding that GDH1 is solely responsible for these differences in ammonia assimilation rate.

  15. New methods to quantify NH3 volatilization from fertilized surface soil with urea

    Directory of Open Access Journals (Sweden)

    Ana Carolina Alves


    Full Text Available Gaseous N losses from soil are considerable, resulting mostly from ammonia volatilization linked to agricultural activities such as pasture fertilization. The use of simple and accessible measurement methods of such losses is fundamental in the evaluation of the N cycle in agricultural systems. The purpose of this study was to evaluate quantification methods of NH3 volatilization from fertilized surface soil with urea, with minimal influence on the volatilization processes. The greenhouse experiment was arranged in a completely randomized design with 13 treatments and five replications, with the following treatments: (1 Polyurethane foam (density 20 kg m-3 with phosphoric acid solution absorber (foam absorber, installed 1, 5, 10 and 20 cm above the soil surface; (2 Paper filter with sulfuric acid solution absorber (paper absorber, 1, 5, 10 and 20 cm above the soil surface; (3 Sulfuric acid solution absorber (1, 5 and 10 cm above the soil surface; (4 Semi-open static collector; (5 15N balance (control. The foam absorber placed 1 cm above the soil surface estimated the real daily rate of loss and accumulated loss of NH3N and proved efficient in capturing NH3 volatized from urea-treated soil. The estimates based on acid absorbers 1, 5 and 10 cm above the soil surface and paper absorbers 1 and 5 cm above the soil surface were only realistic for accumulated N-NH3 losses. Foam absorbers can be indicated to quantify accumulated and daily rates of NH3 volatilization losses similarly to an open static chamber, making calibration equations or correction factors unnecessary.

  16. Effect of Na+ impregnated activated carbon on the adsorption of NH+4-N from aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Mo Shi; Zhengfang Wang; Zheng Zheng


    Two kinds of activated carbons modified by Na+ impregnation after pre-treatments involving oxidation by nitric acid or acidification by hydrochloric acid (denoted as AC/N-Na and AC/HCl-Na,respectively),were used as adsorbents to remove NH4+-N.The surface features of samples were investigated by BET,SEM,XRD and FT-IR.The adsorption experiments were conducted in equilibrium and kinetic conditions.Influencing factors such as initial solution pH and initial concentration were investigated.A possible mechanism was proposed.Results showed that optimal NH4+-N removal efficiency was achieved at a neutral pH condition for the modified ACs.The Langmuir isotherm adsorption equation provided a better fit than other models for the equilibrium study.The adsorption kinetics followed both the pseudo second-order kinetics model and intra-particle kinetic model.Chemical surface analysis indicated that Na+ ions form ionic bonds with available surface functional groups created by pre-treatment,especially oxidation by nitric acid,thus increasing the removal efficiency of the modified ACs for NH4+-N.Na+-impregnated ACs had a higher removal capability in removing NH4+-N than unmodified AC,possibly resulting from higher numbers of surface functional groups and better intra-particle diffusion.The good fit of Langmuir isotherm adsorption to the data indicated the presence of monolayer NH4+-N adsorption on the active homogenous sites within the adsorbents.The applicability of pseudo second-order and intra-particle kinetic models revealed the complex nature of the adsorption mechanism.The intra-particle diffusion model revealed that the adsorption process consisted not only of surface adsorption but also intra-particle diffusion.

  17. NH4Cl对机械活化Al粉燃烧合成AlN的控制%Effects of NH4CI on the synthesis of aluminum nitride by the spontaneous combustion of mechanically activated aluminium powder

    Institute of Scientific and Technical Information of China (English)

    刘建平; 张晖


    添加NH4Cl到经由高能球磨制得的机械活化铝粉中后,铝粉在空气中于室温下即可发生自燃反应.本研究通过含有不同量NH4Cl的机械活化铝粉的自燃制得了Al2O3-AlN疏松粉末,并研究了NH4CL添加量对燃烧产物成分和结构的控制.结果表明:NH4Cl不仅控制了产物的形貌,而且改变了铝粉的氮化初理.在NH4Cl添加量为3%~5%(质量分数)时,所得燃烧产物颗粒大小相对较均匀,并含有700%(质量分数)以上的AlN.%With the addition of NH4CI, the mechanically activated aluminum powder made by high energy ball milling could bum spontaneously in air at room temperature with the formation of Al2O3-AIN powder. In this study, AIN powders were prepared by the spontaneous combustion of aluminum powder including different amounts of NH4CI. The effects of NH4Cl content on the composition and structure of the combustion product were studied by characterizing the phase and morphology of combustion products. The results show that NH4CI not only affects the morphology of products, but also changes the nitridation mechanism of aluminum powder. When 3%~5% (mass fraction) NH4CI is added, the sizes of particles included in the combustion product show small variation and the content of AIN in the combustion product is above 70% (mass fraction).

  18. Effect of organic chain length on structure, electronic composition, lattice potential energy, and optical properties of 2D hybrid perovskites [(NH3)(CH2) n (NH3)]CuCl4, n = 2-9 (United States)

    Abdel-Aal, Seham K.; Kocher-Oberlehner, Gudrun; Ionov, Andrei; Mozhchil, R. N.


    Diammonium series of Cu hybrid perovskites of the formula [(NH3)(CH2) n (NH3)]CuCl4, n = 6-9 are prepared from an ethanolic solution in stoichiometric ratio 1:1 (organic/inorganic). Formation of the desired material was confirmed and characterizes by microchemical analysis, FTIR, XRD and XPS spectra. The structure consists of corner-shared octahedron [CuCl4]2- anion alternative by organic [(NH3)(CH2) n (NH3)]2+ cations. The organic and inorganic layers form infinite 2D sheet that are connected via NH···Cl hydrogen bond. The calculated lattice potential energy U pot (kJ/mol) and lattice enthalpy Δ H L (kJ/mol) are inversely proportional to the molecular volume V m (nm3) and organic chain length. Optical properties show strong absorption peak at UV-visible range. The band gap energy calculated using Kubelka-Munk equation shows the decrease of the energy gap as organic chain length increases. The introduction of bromide ion to [(NH3)(CH2) n (NH3)]CuCl2Br2 denoted 2C7CuCB hybrid has shifted the energy gap to lower values from 2.6 to 2.18 eV for 2C7CuCl (yellow) and 2C7CuCB (brown), respectively, at the same organic chain length. All elements of [(NH3)(CH2)9(NH3)]CuCl4 and [(NH3)(CH2)7(NH3)]CuCl2Br2 were found in XPS spectra, as well as valence band spectra.

  19. Comparison of measured NH4 level and NO emission to declared tar and nicotine values of hundred cigarette brands

    NARCIS (Netherlands)

    Brunt TM; Verlaan APJ; Cleven RFMJ; Rambali B; Vleeming W; LEO; LAC; LPI


    De algemene hypothese bestaat dat NH4 gehalte in sigaretten en NO concentratie in sigarettenrook de nicotine beschikbaarheid in de longen beinvloedt en daardoor ook een factor speelt bij de tabaksverslaving. Een correlatie tussen het NH4 gehalte, de NO emissie en de gedeclareerde nicotine waarde

  20. Complete genome sequence of the cystic fibrosis pathogen Achromobacter xylosoxidans NH44784-1996 complies with important pathogenic phenotypes

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Hansen, Martin Asser; Jensen, Peter Østrup;


    present a complete assembly of the genome of A. xylosoxidans NH44784-1996, an isolate from a cystic fibrosis patient obtained in 1996. The genome of A. xylosoxidans NH44784-1996 contains approximately 7 million base pairs with 6390 potential protein-coding sequences. We identified several features...

  1. Confirmation of Isolated Cu2+ Ions in SSZ-13 Zeolite as Active Sites in NH3-Selective Catalytic Reduction

    NARCIS (Netherlands)

    Deka, U.; Juhin, A.F.; Eilertsen, E.A.; Emerich, H.; Green, M.A.; Korhonen, S.T.; Weckhuysen, B.M.; Beale, A.M.


    NH3-Selective Catalytic Reduction (NH3-SCR) is a widely used technology for NOx reduction in the emission control systems of heavy duty diesel vehicles. Copper-based ion exchanged zeolites and in particular Cu-SSZ-13 (CHA framework) catalysts show both exceptional activity and hydrothermal stability

  2. A Guided-Ion Beam Study of the O+(4S) + NH3 System at Hyperthermal Energies (United States)


    0+ + NH3.6 This work suggests that additional channels, leading to the formation of NH?+ (not distinguishable in the experiment) and HiO + are...a small channel and there are no coincident ions (for ND? reactions, D?0+ coincides with ND4 +, a secondary product). The HiO + cross section is

  3. Solid-phase synthesis of NH-1,2,3-triazoles using 4,4′- bismethoxybenzhydryl azide

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil O'Hanlon; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland


    Readily available 4,4′-bismethoxybenzhydryl azide was found to be a useful building block for the synthesis of NH-1,2,3-triazoles through copper(I)-catalyzed cycloaddition reactions with solid-supported terminal alkynes, followed by acid-mediated deprotection. Peptide-containing NH-1,2,3-triazoles...

  4. Projections of NH3 emissions from manure generated by livestock production in China to 2030 under six mitigation scenarios. (United States)

    Xu, Peng; Koloutsou-Vakakis, Sotiria; Rood, Mark J; Luan, Shengji


    China's rapid urbanization, large population, and increasing consumption of calorie-and meat-intensive diets, have resulted in China becoming the world's largest source of ammonia (NH3) emissions from livestock production. This is the first study to use provincial, condition-specific emission factors based on most recently available studies on Chinese manure management and environmental conditions. The estimated NH3 emission temporal trends and spatial patterns are interpreted in relation to government policies affecting livestock production. Scenario analysis is used to project emissions and estimate mitigation potential of NH3 emissions, to year 2030. We produce a 1km×1km gridded NH3 emission inventory for 2008 based on county-level activity data, which can help identify locations of highest NH3 emissions. The total NH3 emissions from manure generated by livestock production in 2008 were 7.3TgNH3·yr(-1) (interquartile range from 6.1 to 8.6TgNH3·yr(-1)), and the major sources were poultry (29.9%), pigs (28.4%), other cattle (27.9%), and dairy cattle (7.0%), while sheep and goats (3.6%), donkeys (1.3%), horses (1.2%), and mules (0.7%) had smaller contributions. From 1978 to 2008, annual NH3 emissions fluctuated with two peaks (1996 and 2006), and total emissions increased from 2.2 to 7.3Tg·yr(-1) increasing on average 4.4%·yr(-1). Under a business-as-usual (BAU) scenario, NH3 emissions in 2030 are expected to be 13.9TgNH3·yr(-1) (11.5-16.3TgNH3·yr(-1)). Under mitigation scenarios, the projected emissions could be reduced by 18.9-37.3% compared to 2030 BAU emissions. This study improves our understanding of NH3 emissions from livestock production, which is needed to guide stakeholders and policymakers to make well informed mitigation decisions for NH3 emissions from livestock production at the country and regional levels. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Lithium Salt of NH2-substituted Graphene Nanoribbon with Twofold Donor-acceptor Framework: Large Nonlinear Optical Property

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhong-jun; LI Zhi-ru; HUANG Xu-ri; SUN Chia-chung


    Based on graphene, a new class of second-order nonlinear optical(NLO) material, the lithium salt of NH2-substituted graphene nanoribbon with the twofold donor(D)/acceptor(A) mode, was reported. Eight stable 2Li-2NH2-GNR lithium salts, especially cis lithium salts, display considerably large ,β0 values. The combination of NH2-substituting and cis Li-doping makes β0 greatly increased from 0(GNR) to 1.2×105-2.9×105 a.u.(cis-2Li2NH2-GNRs). Our largest β0 value(2.9× l05 a.u.) for cis-2Li-1,3-2NH2-AGNR is comparable to the record value of 1.7× l05 a.u. for a long donor-acceptor polyene.

  6. Structural, electronic properties of microscale (NH4)2V3O8 fabricated using a novel preparation method (United States)

    Zakharova, G. S.; Enyashin, A. N.; Podval'naya, N. V.; Zhuravlev, N. A.; Kuznetsov, M. V.; Gorodetsky, R. S.; Liu, Y.; Zhu, Q.


    A new method has been developed for the synthesis of diammonium trivanadate (NH4)2V3O8. Single crystals of (NH4)2V3O8 were synthesized on a large scale by a soft base hydrolysis of NH4VO3 in NH4OH solution in the presence of VOSO4·3H2O. The effects of vanadium(V) concentration, pH value on the product morphology and phase composition were investigated. The formation mechanism of (NH4)2V3O8 was suggested. The samples were characterized using combination of techniques including X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, nuclear magnetic spectroscopy, nitrogen adsorption/desorption isotherms, and thermal analysis. Electronic structure, chemical bonding and adsorption properties of the bulk compound and (001) surface were analyzed by means of DFT calculations.

  7. Theoretical and experimental investigations of optical, structural and electronic properties of the lower-dimensional hybrid [NH3-(CH2)10-NH3]ZnCl4 (United States)

    El Mrabet, R.; Kassou, S.; Tahiri, O.; Belaaraj, A.; Guionneau, P.


    In the current study, a combination between theoretical and experimental studies has been made for the hybrid perovskite [NH3-(CH2)10-NH3]ZnCl4. The density functional theory (DFT) was performed to investigate structural and electronic properties of the tilted compound. A local approximation (LDA) and semi-local approach (GGA) were employed. The results are obtained using, respectively, the local exchange correlation functional of Perdew-Wang 92 (PW92) and semi local functional of Perdew-Burke-Ernzerhof (PBE). The optimized cell parameters are in good agreement with the experimental results. Electronic properties have been studied through the calculation of band structures and density of state (DOS), while structural properties are investigated by geometry optimization of the cell. Fritz-Haber-Institute (FHI) pseudopotentials were employed to perform all calculations. The optical diffuse reflectance spectra was mesured and applied to deduce the refractive index ( n), the extinction coefficient ( k), the absorption coefficient (α), the real and imaginary dielectric permittivity parts (ɛr,ɛi)) and the optical band gap energy Eg. The optical band gap energy value shows good consistent with that obtained from DFT calculations and reveals the insulating behavior of the material.

  8. Nucleobases and Prebiotic Molecules in Organic Residues Produced from the Ultraviolet Photo-Irradiation of Pyrimidine in NH3 and H2O+NH3 Ices (United States)

    Nuevo, Michel; Milam, Stefanie N.; Sandford, Scott


    Although not yet identified in the interstellar medium (ISM), N-heterocycles including nucleobases the information subunits of DNA and RNA are present in carbonaceous chondrites, which indicates that molecules of biological interest can be formed in non-terrestrial environments via abiotic pathways. Recent laboratory experiments and ab-initio calculations have already shown that the irradiation of pyrimidine in pure H2O ices leads to the formation of a suite of oxidized pyrimidine derivatives, including the nucleobase uracil. In the present work, NH3:pyrimidine and H2O:NH3:pyrimidine ice mixtures with different relative proportions were irradiated with UV photons under astrophysically relevant conditions. Liquid- and gas-chromatography analysis of the resulting organic residues has led to the detection of the nucleobases uracil and cytosine, as well as other species of prebiotic interest such as urea and small amino acids. The presence of these molecules in organic residues formed under abiotic conditions supports scenarios in which extraterrestrial organics that formed in space and were subsequently delivered to telluric planets via comets and meteorites could have contributed to the inventory of molecules that triggered the first biological reactions on their surfaces.

  9. Physiological functions of glucagon-like peptide-1 (9-36) NH2%高血糖素样肽1(9-36) NH2的生理学功能

    Institute of Scientific and Technical Information of China (English)

    郭莉霞; 刘建辉; 殷菲


    Many findings demonstrate that glucagon-like peptide-l( 9-36 )NH2[ GLP-1 (9-36 )NH2] , mostly a cleavage product of GLP-1 (7-36) NH2, has a lot of physiological functions. GLP-1 (9-36)NH2 can reduce postprandial glycemia independently of gastric emptying and insulin secretion, rapidly reverse heart failure, improve end diastolic pressure, markedly stimulate myocardial glucose uptake, exert antioxidant cardioprotective actions, reduce oxidative stress in vasculature tissues independently of GLP-1 receptor, suppress hepatic glucose production , and promote glycogen stores. Thus, GLP-1 (9-36) NH2 is an active peptide with important physiological functions , and it will play an important role in treating obesity and accompanying manifestations of metabolic syndrome, including insulin resistance, cardiovascular disease, and hepatic steatosis.%许多研究表明,高血糖素样肽1 (9-36) NH2[ GLP-1 (9-36) NH2]是GLP-1 (7-36) NH2被二肽基肽酶快速降解后的主要体内存在形式,具有许多的生理学功能.GLP-1 (9-36) NH2中除了具有非依赖于胃排空和胰岛素分泌所致的降低餐后血糖的作用外,GLP-1 (9-36) NH2更多的是直接对外周器官的保护作用,包括快速逆转心力衰竭、改善舒张末期压、快速刺激心肌葡萄糖摄取及减少缺血再灌注对心脏的损伤;以及它具有不依赖于GLP-1受体的血管系统的抗氧化作用和抑制肝脏糖原异生、促进肝糖原的合成.因此,可以说明GLP-1( 9-36) NH2在体内是一个具有重要生理功能的活性肽,而不仅仅是GLP-1 (7-36) NH2的代谢产物.GLP-1 (9-36) NH2对糖尿病及其包括胰岛素抵抗、心血管疾病、肝脏脂肪变性等并发症的治疗将会起到非常重要的作用.

  10. Role of NH2-terminal positively charged residues in establishing membrane protein topology. (United States)

    Parks, G D; Lamb, R A


    The paramyxovirus HN polypeptide is a model type II membrane protein, containing an internal uncleaved signal/anchor (S/A) and is oriented in the membrane with an NH2-terminal cytoplasmic domain and COOH-terminal ectodomain (Ncyt topology). To test the role of NH2-terminal positively charged residues in directing the HN membrane topology, the 3 arginine (Arg) residues within the 17-amino-acid NH2-terminal domain were systematically converted to a glutamine or glutamate, and the topology of the mutant proteins was examined after expression in CV-1 cells. The data indicate that: (i) each of the NH2-terminal Arg residues contributes to the signal directing proper HN topology, since substitutions in any of the three positions resulted in approximately 13-23% inversion into the Nexo form; (ii) substitutions in the Arg directly flanking the signal/anchor domain resulted in slightly more inversion than those which were located more distally; and (iii) substitution with a negatively charged glutamate led to more inversion than did replacement with an uncharged glutamine. The effect of a single Arg to Glu substitution on the HN topology was enhanced when present in the context of a truncated NH2-terminal cytoplasmic tail (3 residues). A comparison of the sequences flanking the signal/anchor of well documented type III proteins showed that the majority of these proteins contain a negatively charged residue flanking the NH2-terminal side. An exception to this rule is the NB protein which contains a single positively charged Arg residue in this position. A chimeric protein containing the NB ectodomain and the HN S/A and HN ectodomain lead to a significant fraction (70%) of the chimeric protein adopting type II topology suggesting that the positive charge flanking the S/A domain is important for establishing type II topology. These data are discussed in the context of the loop model for the biogenesis of integral membrane proteins and the possible signals necessary for


    Directory of Open Access Journals (Sweden)

    S. Sujarwata


    Full Text Available A copper phthalocyanine (CuPc thin film based gas sensor with FET structure and channel length 100 μm has been prepared by VE method and lithography technique to detect NH3, motor cycle exhaust gases and CO. CuPc material layer was deposited on SiO2 by the vacuum evaporator (VE method at room temperature and pressure of 8 x10-4 Pa. The stages of manufacturing gas sensor were Si/SiO2 substrate blenching with ethanol in an ultrasonic cleaner, source, and drain electrodes deposition on the substrate by using a vacuum evaporator, thin film deposition between the source/drain and gate deposition. The sensor response times to NH3, motorcycle exhaust gases and CO were 75 s, 135 s, and 150, respectively. The recovery times were 90 s, 150 s and 225, respectively. It is concluded that the CuPc thin film-based gas sensor with FET structure is the best sensor to detect the NH3 gas.Sensor gas berbasis film tipis copper phthalocyanine (CuPc berstruktur FET dengan panjang channel 100 μm telah dibuatdengan metode VE dan teknik lithography untuk mendeteksi NH3 gas buang kendaraan bermotor dan CO. Lapisan bahan CuPc dideposisikan pada permukaan silikon dioksida (SiO2 dengan metode vacuum evaporator (VE pada temperatur ruang dengan tekanan 8 x10-4 Pa. Tahapan pembuatan sensor gas adalah pencucian substrat Si/SiO2 dengan etanol dalam ultrasonic cleaner, deposisi elektroda source dan drain di atas substrat dengan metode vacuum evaporator, deposisi film tipis diantara source/drain dan deposisi gate. Waktu tanggap sensor terhadap NH3, gas buang kendaraan bermotor dan CO berturut-turut adalah 75 s, 135 s,dan 150 s. Waktu pemulihan berturut-turut adalah 90 s, 150 s,dan 225 s. Disimpulkan bahwa sensor gas berstruktur FET berbasis film tipis CuPc merupakan sensor paling baik untuk mendeteksi adanya gas NH3.

  12. Rovibrationally-resolved photodissociation of NH and application to the solar UV opacity (United States)

    Shen, G.; Kuri, A.; Fontenla, J. M.; Stancil, P. C.; Wang, J. G.


    Rovibrationally-resolved photodissociation cross sections of NH have been evaluated using a combination of ab initio and experimentally derived potential curves and dipole transition moments. Here we present results for the three electronic transitions: 23Σ- interstellar gas, cross sections for X3Σ- (v = 0 , J = 0) to 23Σ- and 23 Π dominate, but for the high density and temperature conditions in stellar atmospheres, the LTE cross section to the A3 Π becomes competitive. Explicit application of the cross sections to the solar UV opacity will be presented. In particular, the NH photodissociation opacity is found to affect the non-LTE behavior of some species such as Cr I and V I. The work at UGA was partially supported by NASA grant HST-AR-11776.01-A. The work of JMF was supported by NASA LWS grant NNX09AJ22G. GS acknowledges travel support by the International Cooperation and Exchange Foundation of CAEP.

  13. Cold collisions of N atoms and NH molecules in magnetic fields

    CERN Document Server

    Zuchowski, Piotr S \\


    We calculate the interaction potential between N atoms and NH molecules and use it to investigate cold and ultracold collisions important for sympathetic cooling. The ratio of elastic to inelastic cross sections is large over a wide range of collision energy and magnetic field for most isotopic combinations, so that sympathetic cooling of NH molecules by N atoms is a good prospect. However, there are important effects due to a p-wave shape resonance that may inhibit cooling in some cases. We show that scaling the reduced mass used in the collision is approximately equivalent to scaling the interaction potential. We then explore the dependence of the scattering properties on the reduced mass and explain the resonant effects observed using angular-momentum-insensitive quantum defect theory

  14. Ocean bacteria: performance on CODCr and NH4(+)-N removal in landfill leachate treatment. (United States)

    Feng, Yali; Yi, Aifei; Li, Haoran; Wang, Weida; Du, Yunlong


    An experiment was carried out to investigate the performance of mixed ocean bacteria, isolated from the ocean sediment, on landfill leachate treatment. In this treatment, ocean bacteria were the only constituent added to remove organics and NH(4)(+)-N. Given their considerable influence on wastewater purification, factors such as inoculum, initial pH, processing time and oxygen condition, were directly involved in this research. As indicated by laboratory test results, chemical oxygen demand (CODCr) and NH(4)(+)-N removal could reach 94.45% and 67.87%, respectively, after 3 days of treatment, in conditions of natural pH 6.3 and with the application of oxygen. The volt-ampere characteristics of the bacteria solution verified the redox-active ability of the bacteria in landfill leachate treatment.

  15. Effective NH2-grafting on attapulgite surfaces for adsorption of reactive dyes. (United States)

    Xue, Ailian; Zhou, Shouyong; Zhao, Yijiang; Lu, Xiaoping; Han, Pingfang


    The amine moiety has an important function in many applications, including, adsorption, catalysis, electrochemistry, chromatography, and nanocomposite materials. We developed an effective adsorbent for aqueous reactive dye removal by modifying attapulgite with an amino-terminated organosilicon (3-aminopropyltriethoxysilane, APTES). Surface properties of the APTES-modified attapulgite were characterized by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption. We evaluated the impact of solvent, APTES concentration, water volume, reaction time, and temperature on the surface modification. NH(2)-attapulgite was used to remove reactive dyes in aqueous solution and showed very high adsorption rates of 99.32%, 99.67%, and 96.42% for Reactive Red 3BS, Reactive Blue KE-R and Reactive Black GR, respectively. These powerful dye removal effects were attributed to strong electrostatic interactions between reactive dyes and the grafted NH(2) groups.

  16. Porous Anatase TiO2 Thin Films for NH3 Vapour Sensing (United States)

    Ponnusamy, Dhivya; Madanagurusamy, Sridharan


    Anatase titanium dioxide (TiO2) thin films were deposited onto cleaned glass substrates by a direct current (DC) reactive magnetron sputtering technique for different deposition times from 10 min to 40 min, which resulted in films of different thicknesses. Characterization techniques, such as x-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM) were used to characterize the structural and morphological properties of the TiO2 thin films. XRD patterns showed the formation of (101) crystal anatase facets. The grain size values of the film increased with increased deposition time, and the films deposited at 40 min exhibited a porous structure. Anatase TiO2 thin films exhibited excellent sensing response, fast response and recovery time, as well as good stability and selectivity towards ammonia (NH3). The enhanced NH3 sensing behavior of anatase TiO2 films is attributed to the porous morphology and oxygen vacancies.


    Directory of Open Access Journals (Sweden)



    Full Text Available Allowing (Cy2NH22.SO4.2H2O or Cy2NH2.HSO4 to react with SnMe3Cl in ethanolic media in two specific ratios the sulphato complexes (mentioned in this paper title were obtained and their infrared study was carried out. Discrete structures containing the complex-anion [SO4(SO4SnMe32]4- consisting of a central bidentate sulphate linked to SnMe3 groups which are then coordinated to monodentate sulphate anions or the complex-anion [(SO46(SnMe35]7- consisting of planar SnMe3 groups, monodentate or bidentate sulphate anions, these complex-anions dimerizing through cations via hydrogen bonds, are suggested.

  18. Room temperature three-photon pumped CH3NH3PbBr3 perovskite microlasers (United States)

    Gao, Yisheng; Wang, Shuai; Huang, Can; Yi, Ningbo; Wang, Kaiyang; Xiao, Shumin; Song, Qinghai


    Hybrid lead halide perovskites have made great strides in next-generation light-harvesting and light emitting devices. Recently, they have also shown great potentials in nonlinear optical materials. Two-photon absorption and two-photon light emission have been thoroughly studied in past two years. However, the three-photon processes are rarely explored, especially for the laser emissions. Here we synthesized high quality CH3NH3PbBr3 perovskite microstructures with solution processed precipitation method and studied their optical properties. When the microstructures are pumped with intense 1240 nm lasers, we have observed clear optical limit effect and the band-to-band photoluminescence at 540 nm. By increasing the pumping density, whispering-gallery-mode based microlasers have been achieved from CH3NH3PbBr3 perovskite microplate and microrod for the first time. This work demonstrates the potentials of hybrid lead halide perovskites in nonlinear photonic devices.


    Directory of Open Access Journals (Sweden)

    N. H. AHMAD


    Full Text Available In this present work, carboxymethyl cellulose (CMC – ammonium chloride (NH4Cl solid polymer electrolyte (SPE films were prepared by solution casting method. The ionic conductivity and electrical properties of SPE films were investigated using Electrical Impedance Spectroscopy. SPE film containing 16 wt. % NH4Cl exhibited the highest ionic conductivity of 1.43 x 10-3 S/cm at ambient temperature, 303K. The temperature dependence SPE films showed an Arrhenius-type relation where the regression values obtained from the log conductivity versus reciprocal temperature is close to unity (R2≈1. The electrical properties have been measured as a function of frequency of Ԑr,Ԑi, Mr, Mi shown a non-Debye type behavior


    Energy Technology Data Exchange (ETDEWEB)

    Congiu, Emanuele; Dulieu, Francois; Chaabouni, Henda; Baouche, Saoud; Lemaire, Jean Louis [LERMA-LAMAp, Universite de Cergy-Pontoise, Observatoire de Paris, ENS, UPMC, UMR 8112 du CNRS, 5 Mail Gay Lussac, 95000 Cergy Pontoise Cedex (France); Fedoseev, Gleb; Ioppolo, Sergio; Lamberts, Thanja; Linnartz, Harold [Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden (Netherlands); Laffon, Carine; Parent, Philippe [Laboratoire de Chimie-Physique, Matiere et Rayonnement, Universite Pierre-et-Marie Curie (Paris 06) and CNRS (UMR 7614), 11 rue Pierre-et-Marie-Curie, 75231 Paris (France); Cuppen, Herma M., E-mail: [Faculty of Science, Radboud University Nijmegen, IMM, P.O. Box 9010, NL 6500 GL Nijmegen (Netherlands)


    Icy dust grains in space act as catalytic surfaces onto which complex molecules form. These molecules are synthesized through exothermic reactions from precursor radicals and, mostly, hydrogen atom additions. Among the resulting products are species of biological relevance, such as hydroxylamine-NH{sub 2}OH-a precursor molecule in the formation of amino acids. In this Letter, laboratory experiments are described that demonstrate NH{sub 2}OH formation in interstellar ice analogs for astronomically relevant temperatures via successive hydrogenation reactions of solid nitric oxide (NO). Inclusion of the experimental results in an astrochemical gas-grain model proves the importance of a solid-state NO+H reaction channel as a starting point for prebiotic species in dark interstellar clouds and adds a new perspective to the way molecules of biological importance may form in space.

  1. Electronic properties of NH4-adsorbed graphene nanoribbon as a promising candidate for a gas sensor

    Directory of Open Access Journals (Sweden)

    Naoki Harada


    Full Text Available The electronic properties of NH4-adsorbed N = 7 armchair graphene nanoribbons (AGNRs were theoretically investigated using self-consistent atomistic simulations to explore the feasibility of AGNRs as a gas sensing material. Whereas a pristine AGNR has a finite band gap and is an intrinsic semiconductor, an NH4-adsorbed AGNR exhibits heavily doped n-type properties similar to a graphene sheet with the molecules adsorbed. The electric characteristics of a back-gated AGNR gas sensor were also simulated and the drain current changed exponentially with increasing number of adsorbed molecules. We may conclude that an AGNR is promising as a highly sensitive gas-sensing material with large outputs.

  2. Pressure-induced structural changes in NH{sub 4}Br

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanping; Huang, Xiaoli; Li, Wenbo; Wang, Lu; Wu, Gang; Zhao, Zhonglong; Duan, Defang; Bao, Kuo; Zhou, Qiang; Liu, Bingbing; Cui, Tian, E-mail: [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China)


    We report angle dispersive X-ray diffraction (XRD) measurements and Raman spectroscopy on NH{sub 4}Br up to 70.0 GPa at room temperature. Three thermodynamically stable phases (phases II, IV, and V) are confirmed and a new possible phase (phase VI) of P2{sub 1}/m symmetry is proposed whose structure was established from Rietveld refinement of synchrotron XRD data for the first time. The phase sequence observed in NH{sub 4}Br is in accordance with phase II → IV → V → VI. Phase V transforms into phase VI at about 57.8 GPa with a huge volume reduction of 30%. Still, the intramolecular distances are analyzed to better understand the nature of structures. The H–H interactions become markedly more important as the N–Br distances are compacted, which is probably the reason of the kink of symmetric stretching band (ν{sub 1}) at the transition pressure.

  3. NH4 + directed assembly of zinc oxide micro-tubes from nanoflakes

    Directory of Open Access Journals (Sweden)

    Yang Weiyi


    Full Text Available Abstract A simple precipitation process followed with the heat treatment was developed to synthesize ZnO micro-tubes by self-assembly of nanoflakes composed of nanoparticles. The resulting ZnO micro-tubes demonstrated excellent photocatalytic performance in degrading methylene blue (MB under UV illumination. It was found that NH4 + ion played a critical role in directing the assembly of the nanoflakes to form the micro-tube structure. A critical reaction ratio existed at or above which the ZnO micro-tubes could be obtained. For the mixtures of solutions of (NH42CO3 and zinc salt, the ratio ( was 2:1.

  4. The human receptor for urokinase plasminogen activator. NH2-terminal amino acid sequence and glycosylation variants

    DEFF Research Database (Denmark)

    Behrendt, N; Rønne, E; Ploug, M;


    -PA. The purified protein shows a single 55-60 kDa band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. It is a heavily glycosylated protein, the deglycosylated polypeptide chain comprising only 35 kDa. The glycosylated protein contains N-acetyl-D-glucosamine and sialic acid......, but no N-acetyl-D-galactosamine. Glycosylation is responsible for substantial heterogeneity in the receptor on phorbol ester-stimulated U937 cells, and also for molecular weight variations among various cell lines. The amino acid composition and the NH2-terminal amino acid sequence are reported....... The protein has a high content of cysteine residues. The NH2-terminal sequence is not closely related to any known sequence. The identification of the purified and sequenced protein with the human u-PA receptor is based on the following findings: 1) the ability of the purified protein to bind u-PA and its...

  5. Solvolysis of benzoyl halides in water/NH4DEHP/isooctane microemulsions. (United States)

    García-Río, L; Hervella, P; Rodríguez-Dafonte, P


    A study was carried out on the solvolysis reactions of different benzoyl halides in microemulsions of water/NH4DEHP/isooctane, where NH4DEHP is ammonium bis(2-ethylhexyl) phosphate. Because of the low solubility of benzoyl halides in water, they are distributed between the continuous medium and the interface of the microemulsion, where the reaction takes place. The application of the pseudophase model has allowed us to obtain the distribution constants and the rate constants at the interface for the benzoyl halides. Reaction mechanisms and the changes in these mechanisms in terms of the water content of the microemulsion have been determined on the basis of kinetic data. The influence of the substituent and the leaving group on the reaction rate has been investigated. A comparison of kinetic results with those previously obtained in water/AOT/isooctane microemulsions allows a kinetic evaluation of the change in the microemulsion properties with the surfactant.

  6. High-resolution absorption measurements of NH3 at high temperatures: 2100-5500 cm-1 (United States)

    Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan; Clausen, Sønnik; Fateev, Alexander


    High-resolution absorption spectra of NH3 in the region 2100-5500 cm-1 at 1027 °C and approximately atmospheric pressure (1045±3 mbar) are measured. An NH3 concentration of 10% in volume fraction is used in the measurements. Spectra are recorded in a high-temperature gas-flow cell using a Fourier Transform Infrared (FTIR) spectrometer at a nominal resolution of 0.09 cm-1. The spectra are analysed by comparison to a variational line list, BYTe, and experimental energy levels determined using the MARVEL procedure. 2308 lines have been assigned to 45 different bands, of which 1755 and 15 have been assigned or observed for the first time in this work.

  7. Rate Constant and Branching Fraction for the NH2 + NO2 Reaction

    DEFF Research Database (Denmark)

    Klippenstein, Stephen J.; Harding, Lawrence B.; Glarborg, Peter


    The NH2 + NO2 reaction has been studied experimentally and theoretically. On the basis of laser photolysis/LIF experiments, the total rate constant was determined over the temperature range 295–625 K as k1,exp(T) = 9.5 × 10–7(T/K)−2.05 exp(−404 K/T) cm3 molecule–1 s–1. This value is in the upper...... may facilitate a small flux between the adducts. High- and low-pressure limit rate coefficients for the various product channels of NH2 + NO2 are determined from the ab initio TST-based master equation calculations for the temperature range 300–2000 K. The theoretical predictions are in good agreement...

  8. Room temperature three-photon pumped CH3NH3PbBr3 perovskite microlasers (United States)

    Gao, Yisheng; Wang, Shuai; Huang, Can; Yi, Ningbo; Wang, Kaiyang; Xiao, Shumin; Song, Qinghai


    Hybrid lead halide perovskites have made great strides in next-generation light-harvesting and light emitting devices. Recently, they have also shown great potentials in nonlinear optical materials. Two-photon absorption and two-photon light emission have been thoroughly studied in past two years. However, the three-photon processes are rarely explored, especially for the laser emissions. Here we synthesized high quality CH3NH3PbBr3 perovskite microstructures with solution processed precipitation method and studied their optical properties. When the microstructures are pumped with intense 1240 nm lasers, we have observed clear optical limit effect and the band-to-band photoluminescence at 540 nm. By increasing the pumping density, whispering-gallery-mode based microlasers have been achieved from CH3NH3PbBr3 perovskite microplate and microrod for the first time. This work demonstrates the potentials of hybrid lead halide perovskites in nonlinear photonic devices.

  9. Electroless Ni-Co-P Coating of Cenospheres Using Ag(NH3)2+ Activator

    Institute of Scientific and Technical Information of China (English)

    ZENG Ai-xiang; XIONG Wei-hao


    Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM),energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS)during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.

  10. Electrical and optical properties of Ar/NH3 atmospheric pressure plasma jet (United States)

    Chang, Zheng-Shi; Yao, Cong-Wei; Chen, Si-Le; Zhang, Guan-Jun


    Inspired by the Penning effect, we obtain a glow-like plasma jet by mixing ammonia (NH3) into argon (Ar) gas under atmospheric pressure. The basic electrical and optical properties of an atmospheric pressure plasma jet (APPJ) are investigated. It can be seen that the discharge mode transforms from filamentary to glow-like when a little ammonia is added into the pure argon. The electrical and optical analyses contribute to the explanation of this phenomenon. The discharge mode, power, and current density are analyzed to understand the electrical behavior of the APPJ. Meanwhile, the discharge images, APPJ's length, and the components of plasma are also obtained to express its optical characteristics. Finally, we diagnose several parameters, such as gas temperature, electron temperature, and density, as well as the density number of metastable argon atoms of Ar/NH3 APPJ to help judge the usability in its applications.

  11. Crystal structure of [Co(NH36][Co(CO4]2

    Directory of Open Access Journals (Sweden)

    Thomas G. Müller


    Full Text Available Hexaamminecobalt(II bis[tetracarbonylcobaltate(-I], [Co(NH36][Co(CO4]2, was synthesized by reaction of liquid ammonia with Co2(CO8. The CoII atom is coordinated by six ammine ligands. The resulting polyhedron, the hexaamminecobalt(II cation, exhibits point group symmetry -3. The Co-I atom is coordinated by four carbonyl ligands, leading to a tetracarbonylcobaltate(−I anion in the shape of a slightly distorted tetrahedron, with point group symmetry 3. The crystal structure is related to that of high-pressure BaC2 (space group R-3m, with the [Co(NH36]2+ cations replacing the Ba sites and the [Co(CO4]− anions replacing the C sites. N—H...O hydrogen bonds between cations and anions stabilize the structural set-up in the title compound.

  12. NH3 (10-00) in the pre-stellar core L1544

    DEFF Research Database (Denmark)

    Caselli, P.; Bizzocchi, L.; Keto, E.


    Pre-stellar cores represent the initial conditions in the process of star and planet formation, therefore it is important to study their physical and chemical structure. Because of their volatility, nitrogen-bearing molecules are key to study the dense and cold gas present in pre-stellar cores....... The NH3 rotational transition detected with Herschel-HIFI provides a unique combination of sensitivity and spectral resolution to further investigate physical and chemical processes in pre-stellar cores. Here we present the velocity-resolved Herschel-HIFI observations of the ortho-NH3(10-00) line at 572...... GHz and study the abundance profile of ammonia across the pre-stellar core L1544 to test current theories of its physical and chemical structure. Recently calculated collisional coefficients have been included in our non-LTE radiative transfer code to reproduce Herschel observations. A gas...

  13. Synthesis and electrical transport of single-crystal NH4V3O8 nanobelts. (United States)

    Mai, L Q; Lao, C S; Hu, B; Zhou, J; Qi, Y Y; Chen, W; Gu, E D; Wang, Z L


    Monoclinic NH(4)V(3)O(8) single-crystalline nanobelts with widths of 80-180 nm, thicknesses of 50-100 nm, and lengths up to tens of micrometers have been synthesized at large scale in an ammonium metavanadate solution by a templates/catalysts-free route. Such nanobelts grow along the direction of [010]. The individual NH(4)V(3)O(8) nanobelt exhibits nonlinear, symmetric current/voltage (I/V) characteristics, with a conductivity of 0.1-1 S/cm at room temperature and a dielectric constant of approximately 130. The dominant conduction mechanism is based on small polaron hopping due to ohmic mechanism at low electric field below 249 V/cm due to Schottky emission at medium electric field between 249 and 600 V/cm and due to the Poole-Frenkel emission mechanism at high field above 600 V/cm.

  14. A new interaction mechanism of LiNH2 with MgH2: magnesium bond. (United States)

    Yang, Xin; Li, Qingzhong; Cheng, Jianbo; Li, Wenzuo


    Quantum chemical calculations were performed for LiNH2-HMgX (X=H, F, Cl, Br, CH3, OH, and NH2) complexes to propose a new interaction mechanism between them. This theoretical survey showed that the complexes are stabilized through the combinative interaction of magnesium and lithium bonds. The binding energies are in the range of 63.2-66.5 kcal mol(-1), i.e., much larger than that of the lithium bond. Upon complexation, both Mg-H and Li-N bonds are lengthened. Substituents increase Mg-H bond elongation and at the same time decrease Li-N bond elongation. These cyclic complexes were characterized with the presence of a ring critical point and natural population analysis charges.

  15. Observation of orbiting resonances in He(3S1) + NH3 Penning ionization


    Jankunas, Justin; Jachymski, Krzysztof; Hapka, Michal; Osterwalder, Andreas


    Resonances are among the clearest quantum mechanical signatures of scattering processes. Previously, shape resonances and Feshbach resonances have been observed in inelastic and reactive collisions involving atoms or diatomic molecules. Structure in the integral cross section has been observed in a handful of elastic collisions involving polyatomic molecules. The present paper presents the observation of shape resonances in the reactive scattering of a polyatomic molecule, NH3. A merged-beam ...

  16. On the NH3 absorption depression observable at Northern low latitudes of Jupiter (United States)

    Tejfel, Victor G.; Vdovichenko, Vladimir D.; Lysenko, Peter G.; Karimov, Alibek M.; Kirienko, Galina A.; Bondarenko, Natalya N.; Kharitonova, Galina


    From February to April of 2016, we carried out a special series of spectrophotometric observations of Jupiter to study the current behavior of the ammonia absorption at the low latitudes of the Northern hemisphere, where in 2004 we have found a well-defined depression of the 787 nm NH3 absorption band intensity (V.Tejfel et al., Bull.AAS, 2005, Vol. 37, p.682). In subsequent years, an existence of this depression was annually confirmed by spectral observations, although we were noticing its variable character. During observations of 2016 we obtained more than 2,500 CCD-spectrograms, including the spectra of the central meridian, the GRS, and 12 scans of Jovian disk on different dates (70 zonal spectra in each scan). The 787 nm NH3 absorption band was extracted with using of ratios of the Jovian spectra to the Saturn's disk spectrum that was taken as a reference. The depression of absorption in this band begins almost from the equator, and its maximum occurs at the planetographic latitude of 100N then the absorption increases again approaching to the latitude of 200N. The equivalent bandwidths corresponding to these latitudes are equal to 18.7 ± 1.4 A, 14.4 ± 1.0 A and 17.8 ± 0.8A. The 645 nm NH3 absorption band also shows depletion at the low latitudes of the Northern hemisphere, but it is less pronounced. At the temperate latitudes of the Northern hemisphere this band's absorption is systematically lower than the Southern Hemisphere's ones. We will continue research in this direction, especially because recently a significant depletion of gaseous NH3 has also been found with using of the VLA with high resolution (I. de Pater et al., Science, 2016, Vol. 352, Issue 6290, p.1290-1294) at the low latitudes of the Northern hemisphere in the region of the NEB.


    Directory of Open Access Journals (Sweden)

    Serigne Fallou Pouye


    Full Text Available The structure of this salt consists of a 3D structure. The anion interacts with NH2 group of the cation and H2O molecules respectively through N-H---O and O-H---O hydrogen bonds. The anion MoO42- is almost perfectly tetrahedral. The four values of the lengths of Mo- O bonds are all equal to 1.7613 Å (12.

  18. Thermodynamic properties of ferroelectric NH3CH2COOH·H2PO3 crystal (United States)

    Zachek, I. R.; Shchur, Ya.; Levitskii, R. R.; Vdovych, A. S.


    Using a modified microscopic model of NH3CH2COOH·H2PO3 by taking into account piezoelectric coupling with strains εi, ε4, ε5 and ε6 in two-particle cluster approximation, the temperature dependence of polarization and tensor of static dielectric permittivity of mechanically clamped and free crystal, their piezoelectric characteristics, elastic constants and heat capacity are calculated.

  19. Photovoltaic performance and the energy landscape of CH3NH3PbI3. (United States)

    Zhou, Yecheng; Huang, Fuzhi; Cheng, Yi-Bing; Gray-Weale, Angus


    Photovoltaic cells with absorbing layers of certain perovskites have power conversion efficiencies up to 20%. Among these materials, CH3NH3PbI3 is widely used. Here we use density-functional theory to calculate the energies and rotational energy barriers of a methylammonium ion in the α or β phase of CH3NH3PbI3 with differently oriented neighbouring methylammonium ions. Our results suggest the methylammonium ions in CH3NH3PbI3 prefer to rotate collectively, and to be parallel to their neighbours. Changes in polarization on rotation of methylammonium ions are two to three times larger than those on relaxation of the lead ion from the centre of its coordination shell. The preferences for parallel configuration and concerted rotation, with the polarisation changes, are consistent with ferroelectricity in the material, and indicate that this polarisation is governed by methylammonium orientational correlations. We show that the field due to this polarisation is strong enough to screen the field hindering charge transport, and find this screening field in agreement with experiment. We examine two possible mechanisms for the effect of methylammonium ion rotation on photovoltaic performance. One is that rearrangement of methylammoniums promotes the creation and transport of charge carriers. Some effective masses change greatly, but changes in band structure with methylammonium rotation are not large enough to explain current-voltage hysteresis behaviour. The second possible mechanism is that polarization screens the hindering electric field, which arises from charge accumulation in the transport layers. Polarization changes on methylammonium rotation favour this second mechanism, suggesting that collective reorientation of methylammonium ions in the bulk crystal are in significant part responsible for the hysteresis and power conversion characteristics of CH3NH3PbI3 photovoltaic cells.

  20. Electron scattering cross sections with HF, OH, NH and CH molecules

    Energy Technology Data Exchange (ETDEWEB)

    Joshipura, K.N. [Sardar Patel Univ., Vallabh Vidyanagar (India). Dept. of Physics; Vinodkumar, M. [Sardar Patel Univ., Vallabh Vidyanagar (India). Dept. of Physics


    Total cross sections including elastic scattering, electronic excitation-ionisation and the dipole rotational excitation are calculated for electron impact on HF, OH, NH, and CH molecules. The additivity rules as well as single-centre expansion are employed for this purpose. A comparison was possible for the e-HF system only. Our results are expected to be good at intermediate to high energies (>50 eV). (orig.).

  1. Effect of dispersed SiO2 on the phase behaviour of NH4HSO4

    Directory of Open Access Journals (Sweden)

    Vargas, R. A.


    Full Text Available Phase equilibria and electrical conductivity of (1-xNH4HSO4-xSiO2 composites were studied by thermal and impedance measurements. Silica with particle size of 14 nm was used. The phase transitions of NH4HSO4 (AHS at 154 K and 420 K (melting point were not affected by the silica doping. No large changes in the low-temperature (T Estudiamos el equilibrio de fases y la conductividad eléctrica de las compositas (1-xNH4HSO4-xSiO2 por medidas térmicas y de impedancia. Se utilizaron partículas de silica de diámetro 14 nm. Las transiciones de fase del NH4HSO4 (AHS en 154 K y 420 K (punto de fusión no fueron afectadas con el dopaje de silica. No se observaron grandes cambios a bajas temperaturas (T < 420 K en la conductividad dc y la relajación eléctrica de las compositas al ser dopadas con silica. La parte imaginaria de la conductividad corregida (después de haber substraído la contribución de la conductividad dc, ε″(ω,T, como función de la frecuencia (f = ω/ 2π y la temperatura muestra un pico de dispersión alrededor de 1 MHz para pequeñas concentraciones de silica, cuya posición (fmax esta también térmicamente activada. Los resultados dieléctricos se discuten en términos del efecto de la polarización de las celdas sobre el movimiento de los protones.

  2. Theoretical Studies on F(-) + NH2Cl Reaction: Nucleophilic Substitution at Neutral Nitrogen. (United States)

    Liu, Xu; Zhang, Jiaxu; Yang, Li; Sun, Rui


    The SN2 reactions at N center, denoted as SN2@N, has been recognized to play a significant role in carcinogenesis, although they are less studied and less understood. The potential energy profile for the model reaction of SN2@N, chloramine (NH2Cl) with fluorine anion (F(-)), has been characterized by extensive electronic structure calculations. The back-side SN2 channel dominates the reaction with the front-side SN2 channel becoming feasible at higher energies. The minimum energy pathway shows a resemblance to the well-known double-well potential model for SN2 reactions at carbon. However, the complexes involving nitrogen on both sides of the reaction barrier are characterized by NH---X (X = F or Cl) hydrogen bond and possess C1 symmetry, in contrast to the more symmetric ion-dipole carbon analogues. In the F(-) + NH2Cl system, the proton transfer pathway is found to become more competitive with the SN2 pathway than in the F(-) + CH3Cl system. The calculations reported here indicate that stationary point properties on the F(-) + NH2Cl potential energy surface are slightly perturbed by the theories employed. The MP2 and CAM-B3LYP, as well as M06-2X and MPW1K functionals give overall best agreement with the benchmark CCSD(T)/CBS energies for the major SN2 reaction channel, and are recommended as the preferred methods for the direct dynamics simulations to uncover the dynamic behaviors of the title reaction.

  3. Combining anti-cancer drugs with artificial sweeteners: synthesis and anti-cancer activity of saccharinate (sac) and thiosaccharinate (tsac) complexes cis-[Pt(sac)2(NH3)2] and cis-[Pt(tsac)2(NH3)2]. (United States)

    Al-Jibori, Subhi A; Al-Jibori, Ghassan H; Al-Hayaly, Lamaan J; Wagner, Christoph; Schmidt, Harry; Timur, Suna; Baris Barlas, F; Subasi, Elif; Ghosh, Shishir; Hogarth, Graeme


    The new platinum(II) complexes cis-[Pt(sac)2(NH3)2] (sac=saccharinate) and cis-[Pt(tsac)2(NH3)2] (tsac=thiosaccharinate) have been prepared, the X-ray crystal structure of cis-[Pt(sac)2(NH3)2] x H2O reveals that both saccharinate anions are N-bound in a cis-arrangement being inequivalent in both the solid-state and in solution at room temperature. Preliminary anti-cancer activity has been assessed against A549 human alveolar type-II like cell lines with the thiosaccharinate complex showing good activity.

  4. General working principles of CH3NH3PbX3 perovskite solar cells. (United States)

    Gonzalez-Pedro, Victoria; Juarez-Perez, Emilio J; Arsyad, Waode-Sukmawati; Barea, Eva M; Fabregat-Santiago, Francisco; Mora-Sero, Ivan; Bisquert, Juan


    Organometal halide perovskite-based solar cells have recently realized large conversion efficiency over 15% showing great promise for a new large scale cost-competitive photovoltaic technology. Using impedance spectroscopy measurements we are able to separate the physical parameters of carrier transport and recombination in working devices of the two principal morphologies and compositions of perovskite solar cells, viz. compact thin films of CH3NH3PbI(3-x)Clx and CH3NH3PbI3 infiltrated on nanostructured TiO2. The results show nearly identical spectral characteristics indicating a unique photovoltaic operating mechanism that provides long diffusion lengths (1 μm). Carrier conductivity in both devices is closely matched, so that the most significant differences in performance are attributed to recombination rates. These results highlight the central role of the CH3NH3PbX3 semiconductor absorber in carrier collection and provide a new tool for improved optimization of perovskite solar cells. We report for the first time a measurement of the diffusion length in a nanostructured perovskite solar cell.

  5. Dynamics of CH3NH3PbI3 from first principles simulations (United States)

    Kachmar, Ali; Carignano, Marcelo


    We address the dynamical and optical properties of CH3NH3PbI3 using molecular dynamics simulations based on forces calculated with density functional theory. We have studied the three stable phases of CH3NH3PbI3 but most of the effort was dedicated to the intermediate tetragonal phase, which is stable at standard ambient conditions. In this case, two different system sizes have been considered, one with 8 unit cells (384 atoms) and a larger one with 27 unit cells (1296 atoms). The total simulated time reached 40 ps. Our findings reveal the interplay between the thermal energy of the system and the electronic degrees of freedom. For example, the organic molecule undergoes relatively fast rotations and the energy band gap, approximated by the LUMO-HOMO energy difference, fluctuates around the equilibrium value of ~1.5 eV with a width of 0.2 eV. The rotation of the CH3NH3 molecule is not isotropic, and more importantly, it is quite sensitive to the size of the simulation box. Our study also provides a quantitative measure for the finite size effects affecting the calculated properties and provides a contextual scenario on which to analyze the more typical density functional theory studies based on static calculations on optimal structures. The authors acknowledge the HPC resources of Texas A&M University at Qatar.

  6. Optimization of exopolysaccharides production by Weissella confusa NH 02 isolated from Thai fermented sausages

    Directory of Open Access Journals (Sweden)

    Suppasil Maneerat


    Full Text Available Exoploysaccharides (EPSs producing lactic acid bacteria (LAB were isolated from Thai traditional fermented foods. Colonies exhibiting a clear zone and ropiness on modified MRS agar containing 2% (w/v sucrose and 0.02% (w/v bromocresol purple were selected for Gram staining and catalase test. From 140 isolates, 120 isolates were identified as LAB. However, only 14 strains were able to produce a large amount of EPSs (>5.9 g/l when cultivated in modified MRS broth containing 2% (w/v sucrose at 37ºC for 24 hrs. The highest viscosity and yield of EPSs were obtained from isolate NH 02. Based on 16S rDNA analysis, strain NH 02 was identified as Weissella confusa. Sucrose (40 g/l, an initial pH of modified MRS at 7.0, and a cultivation temperature of 37ºC were the optimum conditions, in which EPSs were produced at levels up to 18.08 g/l within 12 hrs. EPSs produced by W. confusa NH 02 contained only glucose and had a molecular mass of 1.13106Da. to 18.08 g/l within 12 hrs.

  7. NH4HCO3 gas-generating liposomal nanoparticle for photoacoustic imaging in breast cancer. (United States)

    Xia, Jizhu; Feng, Gang; Xia, Xiaorong; Hao, Lan; Wang, Zhigang


    In this study, we have developed a biodegradable nanomaterial for photoacoustic imaging (PAI). Its biodegradation products can be fully eliminated from a living organism. It is a gas-generating nanoparticle of liposome-encapsulating ammonium bicarbonate (NH4HCO3) solution, which is safe, effective, inexpensive, and free of side effects. When lasers irradiate these nanoparticles, NH4HCO3 decomposes to produce CO2, which can absorb much of the light energy under laser irradiation with a specific wavelength, and then expand under heat to generate a thermal acoustic wave. An acoustic detector can detect this wave and show it as a photoacoustic signal on a display screen. The intensity of the photoacoustic signal is enhanced corresponding to an increase in time, concentration, and temperature. During in vivo testing, nanoparticles were injected into tumor-bearing nude mice through the caudal vein, and photoacoustic signals were detected from the tumor, reaching a peak in 4 h, and then gradually disappearing. There was no damage to the skin or subcutaneous tissue from laser radiation. Our developed gas-generating nanomaterial, NH4HCO3 nanomaterial, is feasible, effective, safe, and inexpensive. Therefore, it is a promising material to be used in clinical PAI.

  8. Crystal Structure Formation of CH3NH3PbI3-xClx Perovskite

    Directory of Open Access Journals (Sweden)

    Shiqiang Luo


    Full Text Available Inorganic-organic hydride perovskites bring the hope for fabricating low-cost and large-scale solar cells. At the beginning of the research, two open questions were raised: the hysteresis effect and the role of chloride. The presence of chloride significantly improves the crystallization and charge transfer property of the perovskite. However, though the long held debate over of the existence of chloride in the perovskite seems to have now come to a conclusion, no prior work has been carried out focusing on the role of chloride on the electronic performance and the crystallization of the perovskite. Furthermore, current reports on the crystal structure of the perovskite are rather confusing. This article analyzes the role of chloride in CH3NH3PbI3-xClx on the crystal orientation and provides a new explanation about the (110-oriented growth of CH3NH3PbI3 and CH3NH3PbI3-xClx.

  9. Hydrogen adsorption and storage on Palladium - functionalized graphene with NH-dopant: A first principles calculation (United States)

    Faye, Omar; Szpunar, Jerzy A.; Szpunar, Barbara; Beye, Aboubaker Chedikh


    We conducted a detailed theoretical investigation of the structural and electronic properties of single and double sided Pd-functionalized graphene and NH-doped Pd-functionalized graphene, which are shown to be efficient materials for hydrogen storage. Nitrene radical dopant was an effective addition required for enhancing the Pd binding on the graphene sheet as well as the storage of hydrogen. We found that up to eight H2 molecules could be adsorbed by double-sided Pd-functionalized graphene at 0 K with an average binding energy in the range 1.315-0.567 eVA gravimetric hydrogen density of 3.622 wt% was reached in the Pd-functionalized graphene on both sides. The binding mechanism of H2 molecules came not only the polarization mechanism between Pd and H atoms but also from the binding of the Pd atoms on the graphene sheet and the orbital hybridization. The most crucial part of our work is measuring the effect of nitrene radical on the H2 adsorption on Pd-functionalized graphene. Our calculations predicted that the addition of NH radicals on Pd-functionalized graphene enhance the binding of H2 molecules, which helps also to avoid the desorption of Pd(H2)n (n = 1-5) complexes from graphene sheet. Our results also predict Pd-functionalized NH-doped graphene is a potential hydrogen storage medium for on-board applications.

  10. Theoretical Study on Dihydrogen Bonds of NH3BH3 with Several Small Molecules

    Institute of Scientific and Technical Information of China (English)

    An-yong Li; Li-fang Xu; Zhou Ling


    The dihydrogen bonds B-H…H-X (X=F, Cl, Br, C, O, N) in the dimer (NH3BH3)2 and the complexes of NH3BH3 with HF, HCl, HBr, H2CO, H2O, and CHaOH were theoretically studied. The results show that formation of the dihydrogen bond leads to elongation and stretch frequency red shift of the BH and XH bonds, except that in the H2CO system, the CH bond blue shifts. For (NH3BH3)2 and the complexes of the halogenides, red shifts of the XH bonds are caused by the intermolecular hyperconjugation a(BH)→σ* (XH). For the system of H2CO, a blue shift of the CH bond is caused by a decrease of the intramolecular hyperconjugation n(O)→σ*(CH). In the other two systems, the red shift of OH bond is systems, red shifts of the BH bonds are caused by two factors: negative repolarization and negative rehybridization of the BH bond, and decrease of occupancy on σ(BH) caused by the intermolecular hyperconjugation σ(BH)→σ* (XH).

  11. Detection of Na+, NH4+, K+ and Ca2+ in the Yoghourt and Beer

    Directory of Open Access Journals (Sweden)

    Dongwu Liu


    Full Text Available Ion Chromatography (IC has been developed for the determination of inorganic ions and organic acids. Chromatography can yield the precise and reproducible data if the experimental condition is kept constant. In this study, the cations Na+, NH+4, K+ and Ca2+ in the yoghourt and beers were determined with the technique of IC. A Dionex ICS-2000 ion chromatograph with a Dionex gradient pump, eluent degassing module and conductivity detector was used. Cations were separated on a CS12 A ion-exchange column, with a CG-12 A guard column and detected after suppression with CSRS 300 cation electrical self-regenerating suppressor. The results indicated that the technique of IC was suitable for the rapid, precise and accurate determination of Na+, NH+4, K+ and Ca2+ in the yoghourt and beer samples. In addition, the acceptable detection limits were obtained for Na+, NH+4, K+ and Ca2+ and the time of analysis was significantly shortened with the technique of IC. The data will provide theories and rapid methods for the supervision of yoghourt and beer quality.

  12. Ab initio study on the mechanism of reaction HNCO+NH2

    Institute of Scientific and Technical Information of China (English)

    冀永强; 雷鸣; 冯文林; 徐振峰


    Ab initio UMP2 and UQCISD(T) calculations, with 6-311G** basis sets, were performed for the titled reactions. The results show that the reactions have two product channels: NH2+ HNCO→NH3+NCO (1) and NH2+HNCO-N2H3+CO (2), where reaction (1) is a hydrogen abstraction reaction via an H-bonded complex (HBC), lowering the energy by 32.48 kJ/mol relative to reactants. The calculated QCISD(T)//MP2(full) energy barrier is 29.04 kJ/mol, which is in excellent accordance with the experimental value of 29.09 kJ/mol. In the range of reaction temperature 2300-2700 K, transition theory rate constant for reaction (1) is 1.68 × 1011- 3.29 × 1011 mL · mol-1· s-1, which is close to the experimental one of 5.0 ×1011 mL× mol-1· s-1 or less. However, reaction (2) is a stepwise reaction proceeding via two orientation modes, cis and trans, and the energy barriers for the rate-control step at our best calculations are 92.79 kJ/mol (for cis-mode) and 147.43 kJ/mol (for trans-mode), respectively, which is much higher than

  13. Adsorption performances and refrigeration application of adsorption working pair of CaCl2-NH3

    Institute of Scientific and Technical Information of China (English)

    WANG Liwei; WANG Ruzhu; WU Jingyi; WANG Kai


    The adsorption performance of CaCl2-NH3 is studied under the condition of different expansion spaces for adsorbent, andthe relationships between adsorption performance of CaCl2-NH3 and the phenomena of swelling and agglomeration during adsorption are researched. It is found that the performance stability is related to the ratio of expansion space to the volume of adsorbent ras, and the performance attenuation is serious in the case of large ras. Severe adsorption hysteresis exists in the process of adsorption and desorption at the same evaporating and condensing temperatures, which is related to the stability constant of chemical reaction. This phenomenon cannot be explained by the theory of physical adsorption. Moderate agglomeration will be beneficial to the formation of ammoniate complex; the magnitude of expansion space will affect adsorption performance. Analysis shows that the activated energy needed in the process of adsorption for the sample with ras of 2:1 is less than that for the sample with ras of 3:1.The refrigeration performance of CaCl2-NH3 is predicted from experiments. The cooling capacity of one adsorption cycle is about 945.4 kJ/kg for the adsorbent with an ras of 2:1 at the evaporating temperature of 0℃.

  14. Diagnosing shock temperature with NH$_3$ and H$_2$O profiles

    CERN Document Server

    Gómez-Ruiz, A I; Viti, S; Jiménez-Serra, I; Navarra, G; Bachiller, R; Caselli, P; Fuente, A; Gusdorf, A; Lefloch, B; Lorenzani, A; Nisini, B


    In a previous study of the L1157 B1 shocked cavity, a comparison between NH$_3$(1$_0$-$0_0$) and H$_2$O(1$_{\\rm 10}$--1$_{\\rm 01}$) transitions showed a striking difference in the profiles, with H$_2$O emitting at definitely higher velocities. This behaviour was explained as a result of the high-temperature gas-phase chemistry occurring in the postshock gas in the B1 cavity of this outflow. If the differences in behaviour between ammonia and water are indeed a consequence of the high gas temperatures reached during the passage of a shock, then one should find such differences to be ubiquitous among chemically rich outflows. In order to determine whether the difference in profiles observed between NH$_3$ and H$_2$O is unique to L1157 or a common characteristic of chemically rich outflows, we have performed Herschel-HIFI observations of the NH$_3$(1$_0$-0$_0$) line at 572.5 GHz in a sample of 8 bright low-mass outflow spots already observed in the H$_2$O(1$_{\\rm 10}$--1$_{\\rm 01}$) line within the WISH KP. We d...

  15. NH4HCO3 gas-generating liposomal nanoparticle for photoacoustic imaging in breast cancer (United States)

    Xia, Jizhu; Feng, Gang; Xia, Xiaorong; Hao, Lan; Wang, Zhigang


    In this study, we have developed a biodegradable nanomaterial for photoacoustic imaging (PAI). Its biodegradation products can be fully eliminated from a living organism. It is a gas-generating nanoparticle of liposome-encapsulating ammonium bicarbonate (NH4HCO3) solution, which is safe, effective, inexpensive, and free of side effects. When lasers irradiate these nanoparticles, NH4HCO3 decomposes to produce CO2, which can absorb much of the light energy under laser irradiation with a specific wavelength, and then expand under heat to generate a thermal acoustic wave. An acoustic detector can detect this wave and show it as a photoacoustic signal on a display screen. The intensity of the photoacoustic signal is enhanced corresponding to an increase in time, concentration, and temperature. During in vivo testing, nanoparticles were injected into tumor-bearing nude mice through the caudal vein, and photoacoustic signals were detected from the tumor, reaching a peak in 4 h, and then gradually disappearing. There was no damage to the skin or subcutaneous tissue from laser radiation. Our developed gas-generating nanomaterial, NH4HCO3 nanomaterial, is feasible, effective, safe, and inexpensive. Therefore, it is a promising material to be used in clinical PAI. PMID:28293107

  16. Chemically driven negative linear compressibility in sodium amidoborane, Na(NH2BH3) (United States)

    Magos-Palasyuk, Ewelina; Fijalkowski, Karol J.; Palasyuk, Taras


    Over the past few years we have been witnessing a surge of scientific interest to materials exhibiting a rare mechanical effect such as negative linear compressibility (NLC). Here we report on strong NLC found in an ionic molecular crystal of sodium amidoborane (NaAB) – easily-accessible, optically transparent material. In situ Raman measurements revealed abnormal elongation of B-N and N-H bonds of NaAB at pressure about 3 GPa. Ab initio calculations indicate the observed spectroscopic changes are due to an isostructural phase transition accompanied by a stepwise expansion of the crystal along c axis. Analysis of calculated charge density distribution and geometry of molecular species (NH2BH3) univocally points to a chemically driven mechanism of NLC – pressure-induced formation of hydrogen bonds. The new H-bond acts as a “pivot screw” coupling N-H covalent bonds of neighbor molecular species – a system resembling a two-lever “jack device” on a molecular scale. A mechanism based on formation of new bonds stands in apparent contrast to mechanisms so far reported in majority of NLC materials where no significant alteration of chemical bonding was observed. The finding therefore suggests a qualitatively new direction in exploration the field towards rational design of incompressible materials.

  17. N-H related defects in GaAsN grown through chemical beam epitaxy (United States)

    Ohshita, Yoshio; Ikeda, Kazuma; Suzuki, Hidetoshi; Machida, Hideaki; Sudoh, Hiroshi; Tanaka, Tomohiro; Honda, Takahiko; Inagaki, Makoto; Yamaguchi, Masafumi


    The local vibration modes of N-H related defects in GaAsN are studied using isotopes. When GaAsN is grown through chemical beam epitaxy (CBE) using triethylgallium/tris(dimethylamino)arsenic/monomethylhydrazine gas, there are several local vibration modes (LVMs) in Fourier transform infrared (FTIR) spectra. Signals with stretching mode peaks at 2952, 3098, and 3125 cm-1 are reported, along with new wagging and stretching mode peaks at 960 and 3011 cm-1, which exist only in crystals grown through CBE. When the film is grown using deuterated MMHy as a nitrogen source, new peaks at 2206, 2302, 2318, 2245, and 714 cm-1 appear. This suggests that D related defects are created because of the deuterated MMHy. The ratios of frequencies of these new peaks to those obtained from crystals grown using MMHy are nearly 1.34. This suggests that all defects in GaAsN grown through CBE, which appear as LVMs, are N-H related defects. Especially, those with LVMs at 960 and 3011 cm-1 are new N-H defects only found in GaAsN grown through CBE.

  18. Structure and stability in TMC-1: analysis of NH$_3$ molecular line and Herschel continuum data

    CERN Document Server

    Fehér, O; Ward-Thompson, D; Kirk, J; Kraus, A; Pelkonen, V -M; Pintér, S; Zahorecz, S


    We observed high S/N, high velocity resolution NH$_3$(1,1) and (2,2) emission on an extended map in TMC-1, a filamentary cloud in a nearby quiescent star forming area. By fitting multiple hyperfine-split line profiles to the NH$_3$(1,1) spectra we derived the velocity distribution of the line components and calculated gas parameters on several positions. Herschel SPIRE continuum observations were reduced and used to calculate the physical parameters of the Planck Galactic Cold Clumps in the region. The Herschel-based column density map of TMC-1 shows a main ridge with two local maxima and a separated peak to the south-west. H$_2$-column densities and dust temperatures are in the range of 0.5-3.3 $\\times$ 10$^{22}$ cm$^{-2}$ and 10.5-12 K, respectively. NH$_3$-column densities are 2.8-14.2 $\\times$ 10$^{14}$ cm$^{-2}$ and and H$_2$-volume densities are 0.4-2.8 $\\times$ 10$^4$ cm$^{-3}$. Kinetic temperatures are typically very low with a minimum of 9 K, and a maximum of 13.7 K was found at the Class I protostar...

  19. Comparison among NH3 and GHGs emissive patterns from different housing solutions of dairy farms (United States)

    Baldini, Cecilia; Borgonovo, Federica; Gardoni, Davide; Guarino, Marcella


    Agriculture and livestock farming are known to be activities emitting relevant quantities of atmospheric pollutants. In particular, in intensive animal farming, buildings can be identified as a relevant source of ammonia and greenhouse gases. This study aimed at: i) determining the emission factors of NH3, N2O, CH4, and CO2 from different dairy farms in Italy, and ii) assessing the effects of the different floor types and manure-handling systems used, in order to minimize the impact of this important productive sector. A measurement campaign was carried out for 27 months in four naturally ventilated dairy cattle buildings with different floor types, layouts and manure management systems, representative of the most common technologies in the north of Italy. Gas emissions were measured with the ;static chamber method;: a chamber was placed above the floor farm and an infrared photoacoustic detector (IPD) was used to monitor gas accumulation over time. In the feeding alleys, emissions of NH3 were higher from solid floors than from flushing systems and perforated floors. N2O emissions were significantly different among farms but the absolute values were relatively low. CH4 and CO2 emissions were higher from perforated floors than from other types of housing solution. Regarding the cubicles, the emissions of NH3 were approximately equal from the two housing solution studied. Contrariwise, N2O, CH4 and CO2 emissions were different between the cubicles with rubber mat and those with straw where the highest values were found.

  20. Laboratory rotational ground state transitions of NH$_3$D$^+$ and CF$^+$

    CERN Document Server

    Stoffels, Alexander; Schlemmer, Stephan; Brünken, Sandra


    Aims. This paper reports accurate laboratory frequencies of the rotational ground state transitions of two astronomically relevant molecular ions, NH3D+ and CF+. Methods. Spectra in the millimeter-wave band were recorded by the method of rotational state-selective attachment of He-atoms to the molecular ions stored and cooled in a cryogenic ion trap held at 4 K. The lowest rotational transition in the A state (ortho state) of NH$_3$D$^+$ ($J_K = 1_0 - 0_0$), and the two hyperfine components of the ground state transition of CF$^+$($J = 1 - 0$) were measured with a relative precision better than $10^{-7}$. Results. For both target ions the experimental transition frequencies agree with recent observations of the same lines in different astronomical environments. In the case of NH$_3$D$^+$ the high-accuracy laboratory measurements lend support to its tentative identification in the interstellar medium. For CF$^+$ the experimentally determined hyperfine splitting confirms previous quantum-chemical calculations a...

  1. Ammonia mobility in chabazite: insight into the diffusion component of the NH3-SCR process. (United States)

    O'Malley, Alexander J; Hitchcock, Iain; Sarwar, Misbah; Silverwood, Ian P; Hindocha, Sheena; Catlow, C Richard A; York, Andrew P E; Collier, P J


    The diffusion of ammonia in commercial NH3-SCR catalyst Cu-CHA was measured and compared with H-CHA using quasielastic neutron scattering (QENS) and molecular dynamics (MD) simulations to assess the effect of counterion presence on NH3 mobility in automotive emission control relevant zeolite catalysts. QENS experiments observed jump diffusion with a jump distance of 3 Å, giving similar self-diffusion coefficient measurements for both Cu- and H-CHA samples, in the range of ca. 5-10 × 10(-10) m(2) s(-1) over the measured temperature range. Self-diffusivities calculated by MD were within a factor of 6 of those measured experimentally at each temperature. The activation energies of diffusion were also similar for both studied systems: 3.7 and 4.4 kJ mol(-1) for the H- and Cu-chabazite respectively, suggesting that counterion presence has little impact on ammonia diffusivity on the timescale of the QENS experiment. An explanation is given by the MD simulations, which showed the strong coordination of NH3 with Cu(2+) counterions in the centre of the chabazite cage, shielding other molecules from interaction with the ion, and allowing for intercage diffusion through the 8-ring windows (consistent with the experimentally observed jump length) to carry on unhindered.

  2. N-H stretching modes around 3300 wavenumber from peptide backbones observed by chiral sum frequency generation vibrational spectroscopy. (United States)

    Fu, Li; Wang, Zhuguang; Yan, Elsa C Y


    We present a detailed analysis of the molecular origin of the chiral sum frequency generation (SFG) signals of proteins and peptides at interfaces in the N-H stretching vibrational region. The N-H stretching can be a probe for investigating structural and functional properties of proteins, but remains technically difficult to analyze due to the overlapping with the O-H stretching of water molecules. Chiral SFG spectroscopy offers unique tools to study the N-H stretching from proteins at interfaces without interference from the water background. However, the molecular origin of the N-H stretching signals of proteins is still unclear. This work provides a justification of the origin of chiral N-H signals by analyzing the vibrational frequencies, examining chiral SFG theory, studying proton (hydrogen/deuterium) exchange kinetics, and performing optical control experiments. The results demonstrate that the chiral N-H stretching signals at ~3300 cm(-1) originate from the amide group of the protein backbones. This chiral N-H stretching signal offers an in situ, real-time, and background-free probe for interrogating the protein structures and dynamics at interfaces at the molecular level. © 2014 Wiley Periodicals, Inc.

  3. Tomato Growth and Organic Acid Changes in Response to Partial Replacement of NO-3-N by NH+4-N

    Institute of Scientific and Technical Information of China (English)

    DONG Cai-Xia; SHEN Qi-Rong; WANG Ge


    A hydroponic experiment was conducted to study the effect of partial replacement of NO-3-N by NH4+-N on the seedling growth and organic acid content of tomato (Lycopersicon esculentum Mill.). A completely randomized design was established with three replications and five treatments, i.e., NO-3-N/NH4+-N of 100/0, 75/25, 50/50, 25/75 and 0/100. Results showed that 25% replacement of NO3--N by NH4+-N significantly (P = 0.05) improved fresh and dry weight, revealing that a proper percentage of NH4+-N was important for tomato nitrogen nutrition. This could increase the plant growth even though tomato was a crop that preferred nitrate nutrition. Also an increase in the proportion of NH4+-N in the nutrient solution led to a significant decrease (P = 0.05) in malate, citrate and fumarate. However, the 25% NH4+-N plus 75% NO3--N treatment had no significant effect (P = 0.05) on the 2-ketoglutarate, succinate or oxalic acid content, showing that only some organic acids in tomato plants were affected. Only pyruvate increased significantly (P = 0.05), and it only increased for 25% and 50% replacement of NO3--N by NH4+-N. Metabolism of these organic acids, especially malate, citrate and fumarate, should be further studied at the molecular level in vegetables applied with different nitrogen forms.

  4. Four-Terminal Tandem Solar Cells Using CH3NH3PbBr3 by Spectrum Splitting. (United States)

    Sheng, Rui; Ho-Baillie, Anita W Y; Huang, Shujuan; Keevers, Mark; Hao, Xiaojing; Jiang, Liangcong; Cheng, Yi-Bing; Green, Martin A


    In this work, the use of a high bandgap perovskite solar cell in a spectrum splitting system is demonstrated. A remarkable energy conversion efficiency of 23.4% is achieved when a CH3NH3PbBr3 solar cell is coupled with a 22.7% efficient silicon passivated emitter rear locally diffused solar cell. Relative enhancements of >10% are demonstrated by CH3NH3PbBr3/CH3NH3PbI3 and CH3NH3PbBr3/multicrystalline-screen-printed-Si spectral splitting systems with tandem efficiencies of 13.4% and 18.8%, respectively. The former is the first demonstration of an all perovskite split spectrum system. The CH3NH3PbBr3 cell on a mesoporous structure was fabricated by the vapor-assisted method while the planar CH3NH3PbI3 cell was fabricated by the gas-assisted method. This work demonstrates the advantage of the higher voltage output from the high bandgap CH3NH3PbBr3 cell and its suitability in a tandem system.

  5. Kinetic studies and evaluation of potential compounds for the chemotherapy of Leishmaniasis using LdNH-MBP

    Energy Technology Data Exchange (ETDEWEB)

    Renno, M.N.; Figueroa-Villar, J.D. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Dept. de Quimica; Silva, N.B. da; Tinoco, L.W. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Nucleo de Pesquisas de Produtos Naturais; Borja-Cabrera, G.P.; Palatnik-de-Sousa, C.B.P. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Inst. de Microbiologia


    Full text: Protozoan parasites rely exclusively on purine salvage from the host for DNA and RNA synthesis and nucleoside hydrolases (N Hs) are the enzymes that catalyze the N-rib osyl hydrolysis of all commonly occurring purine and pi rimidine nucleosides, thus being excellent targets for the design of antiparasitic compounds. The general aim of our work with Leishmania donovani NH (LdNH) is to find new inhibitors for this enzyme as potential agents for the chemotherapy of visceral leishmaniasis. In this part of the work we expressed LdNH bound to maltose-binding protein (MBP) in E. coli using the pMAL-C2x vector. After purification by affinity chromatography the enzyme activity was monitored by UV (280 nm) and {sup 1}H NMR spectroscopy using inosine as substrate. All the assays were carried out at 25 deg C in phosphate buffer (pH 8.0) in water (UV) and D{sub 2}O (NMR). Our results show that LdNH-MBP behaves kinetically in the same way as it have been reported for free LdNH, thus confirming that LdNH-MBP maintains the appropriate folding and activity of the enzyme active site, thus being a good model to develop and evaluate new inhibitors of LdNH. As an example, the kinetics tests with AZT have shown that this compound is not an effective inhibitor of this enzyme.

  6. Vibrational spectroscopic study of ionic association in poly(ethylene oxide)-NH4SCN polymer electrolytes. (United States)

    Zhang, Hucheng; Wang, Jianji


    The polymer-ammonium complexes are an important class of proton conducting polymer electrolytes. In this work, poly(ethylene oxide) (PEO)-NH(4)SCN electrolytes were prepared over a large range of the salt content, and their FT-IR spectra were measured at room temperature. Based on the assignments of each band in the spectral envelope of SCN(-1), their relative intensities are determined by the use of FT-IR technique. Following the experimental results and spectral analyses, this paper reports the interactions, the various ionic associations, the changes of the ionic association with NH(4)SCN content, and the characteristics of structure in PEO-NH(4)SCN electrolytes. It is shown that the hydrogen bonds of PEO and NH(4)SCN exert the great effect to the ionic association, the interactions of PEO with NH(4)SCN, and PEO crystallinity, in particular, under the condition of high NH(4)SCN content. In addition, the differences of ionic association among PEO-NaSCN, PEO-KSCN and NH(4)SCN electrolytes are also compared in this paper.

  7. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem model

    Directory of Open Access Journals (Sweden)

    J. O. Bash


    Full Text Available Atmospheric ammonia (NH3 is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air–surface exchange of NH3 is bidirectional. However, the effects of bidirectional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency's (EPA Community Multiscale Air-Quality (CMAQ model with bidirectional NH3 exchange has been coupled with the United States Department of Agriculture's (USDA Environmental Policy Integrated Climate (EPIC agroecosystem model. The coupled CMAQ-EPIC model relies on EPIC fertilization timing, rate and composition while CMAQ models the soil ammonium (NH4+ pool by conserving the ammonium mass due to fertilization, evasion, deposition, and nitrification processes. This mechanistically coupled modeling system reduced the biases and error in NHx (NH3 + NH4+ wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS domain simulation when compared to a 2002 annual simulation of CMAQ without bidirectional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bidirectional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI, with lower emissions in the spring and fall and higher emissions in July.

  8. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem model (United States)

    Bash, J. O.; Cooter, E. J.; Dennis, R. L.; Walker, J. T.; Pleim, J. E.


    Atmospheric ammonia (NH3) is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air-surface exchange of NH3 is bidirectional. However, the effects of bidirectional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency's (EPA) Community Multiscale Air-Quality (CMAQ) model with bidirectional NH3 exchange has been coupled with the United States Department of Agriculture's (USDA) Environmental Policy Integrated Climate (EPIC) agroecosystem model. The coupled CMAQ-EPIC model relies on EPIC fertilization timing, rate and composition while CMAQ models the soil ammonium (NH4+) pool by conserving the ammonium mass due to fertilization, evasion, deposition, and nitrification processes. This mechanistically coupled modeling system reduced the biases and error in NHx (NH3 + NH4+) wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS) domain simulation when compared to a 2002 annual simulation of CMAQ without bidirectional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bidirectional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI), with lower emissions in the spring and fall and higher emissions in July.

  9. Kevlar织物NH3等离子体表面改性研究%Study on NH3 Plasma Surface Modification of Kevlar Fabric

    Institute of Scientific and Technical Information of China (English)

    周正刚; 李敏; 蒋诗才


    采用NH3等离子体对Kevlar-49 S500织物进行了表面改性,处理工艺条件为74.9Pa/113W/14.3分钟.研究结果表明改性后的Kevlar-49 S500织物增强的3234环氧树脂复合材料层间剪切强度提高了26.6%,T型剥离强度提高了22.9%;改性后的纤维表面粗糙度明显增大,与水的接触角降低;T-剥离试样断口的微观分析发现Kevlar纤维/3234环氧界面的破坏方式为纤维本体破坏.

  10. DRIFT study of manganese/ titania-based catalysts for low-temperature selective catalytic reduction of NO with NH3. (United States)

    Wu, Zhongbiao; Jiang, Boqiong; Liu, Yue; Wang, Haiqiang; Jin, Ruiben


    Manganese oxides and iron-manganese oxides supported on TiO2 were prepared by the sol-gel method and used for low-temperature selective catalytic reduction (SCR) of NO with NH3. Base on the previous study, Mn(0.4)/ TiO2 and Fe(0.1)-Mn(0.4)/TiO2 were then selected to carry out the in situ diffuse reflectance infrared transform spectroscopy (DRIFT) investigation for revealing the reaction mechanism. The DRIFT spectroscopy for the adsorption of NH3 indicated the presence of coordinated NH3 and NH4+ on both of the two catalysts. When NO was introduced, the coordinated NH3 on the catalyst surface was consumed rapidly, indicating these species could react with NO effectively. When NH3 was introduced into the sample preadsorbed with NO + O2, SCR reaction would not proceed on Mn(0.4)/TiO2. However, for Fe(0.1)-Mn(0.4)/ TiO2 the bands due to coordinated NH3 on Fe2O3 were formed. Simultaneously, the bidentate nitrates were transformed to monodentate nitrates and NH4+ was detected. And NO2 from the oxidation of NO on catalyst could react with NH4+ leading to the reduction of NO. Therefore, it was suggested that the SCR reaction on Fe(0.1)-Mn(0.4)/TiO2 could also take place in a different way from the reactions on Mn(0.4)/TiO2 proposed by other researchers. Furthermore, the SCR reaction steps for these two kinds of catalysts were proposed.

  11. Estimation of NH3 emissions from a naturally ventilated livestock farm using local-scale atmospheric dispersion modelling

    Directory of Open Access Journals (Sweden)

    P. Cellier


    Full Text Available Agricultural livestock represents the main source of ammonia (NH3 in Europe. In recent years, reduction policies have been applied to reduce NH3 emissions. In order to estimate the impacts of these policies, robust estimates of the emissions from the main sources, i.e. livestock farms are needed. In this paper, the NH3 emissions were estimated from a naturally ventilated livestock farm in Braunschweig, Germany during a joint field experiment of the GRAMINAE European project. An inference method was used with a Gaussian-3D plume model and with the Huang 3-D model. NH3 concentrations downwind of the source were used together with micrometeorological data to estimate the source strength over time. Mobile NH3 concentration measurements provided information on the spatial distribution of source strength. The estimated emission strength ranged between 6.4±0.18 kg NH3 d−1 (Huang 3-D model and 9.2±0.7 kg NH3 d−1 (Gaussian-3D model. These estimates were 94% and 63% of what was obtained using emission factors from the German national inventory (9.6 kg d−1 NH3. The effect of deposition was evaluated with the FIDES-2D model. This increased the emission estimate to 11.7 kg NH3 d−1, showing that deposition can explain the observed difference. The daily pattern of the source was correlated with net radiation and with the temperature inside the animal houses. The daily pattern resulted from a combination of a temperature effect on the source concentration together with an effect of variations in free and forced convection of the building ventilation rate. Further development of the plume technique is especially relevant for naturally ventilated farms, since the variable ventilation rate makes other emission measurements difficult.


    Energy Technology Data Exchange (ETDEWEB)

    Cyganowski, C. J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Koda, J.; Towers, S.; Meyer, J. Donovan [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Rosolowsky, E. [Department of Physics and Astronomy, University of British Columbia, Okanagan, Kelowna BC V1V 1V7 (Canada); Egusa, F. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Momose, R. [Department of Astronomy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Robitaille, T. P., E-mail: [Max Planck Institute for Astronomy, Heidelberg (Germany)


    We present the results of a Nobeyama 45 m H{sub 2}O maser and NH{sub 3} survey of all 94 northern GLIMPSE extended green objects (EGOs), a sample of massive young stellar objects (MYSOs) identified based on their extended 4.5 {mu}m emission. We observed the NH{sub 3}(1,1), (2,2), and (3,3) inversion lines, and detected emission toward 97%, 63%, and 46% of our sample, respectively (median rms {approx} 50 mK). The H{sub 2}O maser detection rate is 68% (median rms {approx} 0.11 Jy). The derived H{sub 2}O maser and clump-scale gas properties are consistent with the identification of EGOs as young MYSOs. To explore the degree of variation among EGOs, we analyze subsamples defined based on mid-infrared (MIR) properties or maser associations. H{sub 2}O masers and warm dense gas, as indicated by emission in the higher-excitation NH{sub 3} transitions, are most frequently detected toward EGOs also associated with both Class I and II CH{sub 3}OH masers. Ninety-five percent (81%) of such EGOs are detected in H{sub 2}O (NH{sub 3}(3,3)), compared to only 33% (7%) of EGOs without either CH{sub 3}OH maser type. As populations, EGOs associated with Class I and/or II CH{sub 3}OH masers have significantly higher NH{sub 3} line widths, column densities, and kinetic temperatures than EGOs undetected in CH{sub 3}OH maser surveys. However, we find no evidence for statistically significant differences in H{sub 2}O maser properties (such as maser luminosity) among any EGO subsamples. Combining our data with the 1.1 mm continuum Bolocam Galactic Plane Survey, we find no correlation between isotropic H{sub 2}O maser luminosity and clump number density. H{sub 2}O maser luminosity is weakly correlated with clump (gas) temperature and clump mass.

  13. Synergetic formation of secondary inorganic and organic aerosol: effect of SO2 and NH3 on particle formation and growth (United States)

    Chu, Biwu; Zhang, Xiao; Liu, Yongchun; He, Hong; Sun, Yele; Jiang, Jingkun; Li, Junhua; Hao, Jiming


    The effects of SO2 and NH3 on secondary organic aerosol formation have rarely been investigated together, while the interactive effects between inorganic and organic species under highly complex pollution conditions remain uncertain. Here we studied the effects of SO2 and NH3 on secondary aerosol formation in the photooxidation system of toluene/NOx in the presence or absence of Al2O3 seed aerosols in a 2 m3 smog chamber. The presence of SO2 increased new particle formation and particle growth significantly, regardless of whether NH3 was present. Sulfate, organic aerosol, nitrate, and ammonium were all found to increase linearly with increasing SO2 concentrations. The increases in these four species were more obvious under NH3-rich conditions, and the generation of nitrate, ammonium, and organic aerosol increased more significantly than sulfate with respect to SO2 concentration, while sulfate was the most sensitive species under NH3-poor conditions. The synergistic effects between SO2 and NH3 in the heterogeneous process contributed greatly to secondary aerosol formation. Specifically, the generation of NH4NO3 was found to be highly dependent on the surface area concentration of suspended particles, and increased most significantly with SO2 concentration among the four species under NH3-rich conditions. Meanwhile, the absorbed NH3 might provide a liquid surface layer for the absorption and subsequent reaction of SO2 and organic products and, therefore, enhance sulfate and secondary organic aerosol (SOA) formation. This effect mainly occurred in the heterogeneous process and resulted in a significantly higher growth rate of seed aerosols compared to without NH3. By applying positive matrix factorisation (PMF) analysis to the AMS data, two factors were identified for the generated SOA. One factor, assigned to less-oxidised organic aerosol and some oligomers, increased with increasing SO2 under NH3-poor conditions, mainly due to the well-known acid catalytic effect of

  14. NH-type of chiral Ni(II) complexes of glycine Schiff base: design, structural evaluation, reactivity and synthetic applications. (United States)

    Bergagnini, Mackenzie; Fukushi, Kazunobu; Han, Jianlin; Shibata, Norio; Roussel, Christian; Ellis, Trevor K; Aceña, José Luis; Soloshonok, Vadim A


    The work being reported here deals with the design of a new type of "N-H" Ni(II) complexes of glycine Schiff bases and study general aspects of their reactivity. It was confirmed that the presence of NH function in these Ni(II) complexes does not interfere with the homologation of the glycine residue, rendering these derivatives of high synthetic value for the general synthesis of α-amino acids. In particular, the practical application of these NH-type complexes was demonstrated by asymmetric synthesis of various β-substituted pyroglutamic acids via Michael addition reactions with chiral Michael acceptors.

  15. Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition

    Directory of Open Access Journals (Sweden)

    Li-Min Chao


    Full Text Available In our study, one-dimensional PbI2/polyvinylpyrrolidone (PVP composition fibers have been prepared by using PbI2 and PVP as precursors dissolved in N,N-dimethylformamide via a electrospinning process. Dipping the fibers into CH3NH3I solution changed its color, indicating the formation of CH3NH3PbI3, to obtain CH3NH3PbI3/PVP composite fibers. The structure, morphology and composition of the all as-prepared fibers were characterized by using X-ray diffraction and scanning electron microscopy.

  16. Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition (United States)

    Chao, Li-Min; Tai, Ting-Yu; Chen, Yueh-Ying; Lin, Pei-Ying; Fu, Yaw-Shyan


    In our study, one-dimensional PbI2/polyvinylpyrrolidone (PVP) composition fibers have been prepared by using PbI2 and PVP as precursors dissolved in N,N-dimethylformamide via a electrospinning process. Dipping the fibers into CH3NH3I solution changed its color, indicating the formation of CH3NH3PbI3, to obtain CH3NH3PbI3/PVP composite fibers. The structure, morphology and composition of the all as-prepared fibers were characterized by using X-ray diffraction and scanning electron microscopy. PMID:28793517

  17. Hydrogen release and structural transformations in LiNH{sub 2}-MgH{sub 2} systems

    Energy Technology Data Exchange (ETDEWEB)

    Pottmaier, D. [Dipartimento di Chimica IFM and NIS, Universita di Torino - Turin (Italy); Dolci, F. [Institute for Energy DG, Joint Research Center - Petten (Netherlands); Orlova, M.; Vaughan, G. [ID11, European Synchrotron Radiation Facility - Grenoble (France); Fichtner, M.; Lohstroh, W. [Institute of Nanotechnology, Karlsruhe Institute of Technology - Karlsruhe (Germany); Baricco, M., E-mail: [Dipartimento di Chimica IFM and NIS, Universita di Torino - Turin (Italy)


    Research highlights: > H{sub 2} release in LiNH{sub 2}-MgH{sub 2} system depends on Li:Mg ratio and ball milling conditions (rpm). > Li:Mg (600 rpm) forms an unknown phase (Fm3m cubic) during ball milling. > Li:Mg (100 rpm) releases simultaneously H{sub 2} and NH{sub 3}. > Li2:Mg (600 rpm) and Li:Mg (100 rpm) decompose into Li{sub 2}Mg(NH){sub 2} and LiMgN through intermediate Mg(NH{sub 2}){sub 2}. > Li:Mg at 600 rpm presents a unique deydrogenation reaction into Li{sub 2}Mg(NH){sub 2}. - Abstract: Reactive hydride composites are good candidates for solid hydrogen storage due to their high gravimetric capacity, cyclability, and suitable thermodynamic properties. The LiNH{sub 2}-MgH{sub 2} system is promising as changes in stoichiometry and milling conditions may result in tailoring of these properties. In this work, LiNH{sub 2}-MgH{sub 2} with different ratios (Li2:Mg, Li:Mg) and ball milling conditions (100, 600 rpm) were investigated. Thermal desorption profiles shows hydrogen release starting at 125 deg. C for Li2:Mg 600 sample and at 225 deg. C for Li:Mg 600 sample, while for Li:Mg 100 sample simultaneous hydrogen and ammonia release at 175 deg. C is observed. In-situ synchrotron X-ray diffraction shows the related structural transformations, such as formation of Mg(NH{sub 2}){sub 2} and allotropic transformation of {alpha} into {beta}-Li{sub 2}Mg(NH){sub 2} for Li2:Mg 600 sample at 350 deg. C or direct formation of {beta}-Li{sub 2}Mg(NH){sub 2} for Li:Mg 100 sample at 370 deg. C. Different polymorphs of the LiMgN phase were also observed during cooling for these two samples. For the Li:Mg 600 sample, transformation occurs in a unique reaction from an unknown phase into {beta}-Li{sub 2}Mg(NH){sub 2} at 290 deg. C. The unknown phase is indexed as a Fm3m cubic similar to the high temperature {gamma}-Li{sub 2}Mg(NH){sub 2}.

  18. Study on the influence of CaO on NH{sub 3}+NO+O{sub 2} reaction system in pre-calciner

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J.S.; Song, Q.; Fu, S.L.; Wu, X.Y.; Yao, Q. [Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering


    This paper studied the influence of CaO on NH{sub 3}+NO+O{sub 2} reaction system in pre-calciner. Experiments were carried out in a fixed bed reactor. Influence of CaO on NH{sub 3}+NO+O{sub 2} reaction, NH{sub 3} oxidation, NH{sub 3} decomposition and NO reduction by NH{sub 3} at O{sub 2} free condition were studied. NH{sub 3} conversion rates and product selectivities were obtained for each reaction condition. It was proved that the influence of CaO on SNCR performance changed with temperature. CaO promoted SNCR performance at 650 C and changed to inhibit SNCR performance when temperature increased above 700 C. CaO influenced the reaction of NH{sub 3}+NO+O{sub 2} mainly by catalyzing NH{sub 3} oxidation. NH{sub 3} conversion rate and NO selectivity decreased when NH{sub 3} concentration increased. Addition of NO into NH{sub 3} heterogeneous oxidation had little effect on NH{sub 3} conversion rate but decreased NO selectivity. A reaction mechanism for NH{sub 3}NO+O{sub 2} reaction on CaO surface was proposed. Heterogeneous reaction model of NH{sub 3}+NO+O{sub 2} on CaO surface was established based on the proposed reaction mechanism. Numerical results showed that the reaction model in this paper could predict NH3 oxidation and NH{sub 3}+NO+O{sub 2} reaction on CaO surface very well.

  19. Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)

    CERN Document Server

    Persson, C M; Hassel, G E; Olofsson, A O H; Black, J H; Herbst, E; Müller, H S P; Cernicharo, J; Wirström, E S; Olberg, M; Hjalmarson, Å; Lis, D C; Cuppen, H M; Gerin, M; Menten, K M


    The understanding of interstellar nitrogen chemistry has improved significantly with recent results from the Herschel Space Observatory. To set even better constraints, we report here on deep searches for the NH+ ground state rotational transition J=1.5-0.5 of the ^2Pi_1/2 lower spin ladder, with fine-structure transitions at 1013 and 1019 GHz, and the para-NH2- 1_1,1-0_0,0 rotational transition at 934 GHz towards Sgr B2(M) and G10.6-0.4 using Herschel-HIFI. No clear detections of NH+ are made and the derived upper limits are <2*10^-12 and <7*10^-13 in Sgr B2(M) and G10.6-0.4, respectively. The searches are complicated by the fact that the 1013 GHz transition lies only -2.5 km/s from a CH2NH line, seen in absorption in Sgr B2(M), and that the hyperfine structure components in the 1019 GHz transition are spread over 134 km/s. Searches for the so far undetected NH2- anion turned out to be unfruitful towards G10.6-0.4, while the para-NH2- 1_1,1-0_0,0 transition was tentatively detected towards Sgr B2(M) at...

  20. HBP-NH2接枝氧化棉织物制备工艺探讨%Preparation of oxidized cotton fabric grafted with HBP-NH2

    Institute of Scientific and Technical Information of China (English)

    张峰; 陈宇岳; 张德锁; 华琰蓉; 赵兵


    以水溶性端氨基超支化合物(HBP-NH2)为改性剂,用高碘酸钠选择性氧化棉织物而制得HBP-NH2接枝氧化棉织物(HGCF).研究了氧化棉织物中醛基含量、HBP-NH2溶液浓度、pH值、反应时间和反应温度等因素对HBP-NH2接枝氧化棉织物活性染料无盐染色性能的影响.结果表明,采用醛基含量为8 mmol/g左右的氧化棉织物,在pH值7.0~8.0的10 g/L HBP-NH2水溶液中,60℃反应5 min,可获得理想的HBP-NH2接枝氧化棉织物;采用活性染料对其无盐染色,可获得满意的染色效果.

  1. MOFabric: Electrospun Nanofiber Mats from PVDF/UiO-66-NH2 for Chemical Protection and Decontamination. (United States)

    Lu, Annie Xi; McEntee, Monica; Browe, Matthew A; Hall, Morgan G; DeCoste, Jared B; Peterson, Gregory W


    Textiles capable of capture and detoxification of toxic chemicals, such as chemical-warfare agents (CWAs), are of high interest. Some metal-organic frameworks (MOFs) exhibit superior reactivity toward CWAs. However, it remains a challenge to integrate powder MOFs into engineered materials like textiles, while retaining functionalities like crystallinity, adsorptivity, and reactivity. Here, we present a simple method of electrospinning UiO-66-NH2, a zirconium MOF, with polyvinylidene fluoride (PVDF). The electrospun composite, which we refer to as "MOFabric", exhibits comparable crystal patterns, surface area, chlorine uptake, and simulant hydrolysis to powder UiO-66-NH2. The MOFabric is also capable of breaking down GD (O-pinacolyl methylphosphonofluoridae) faster than powder UiO-66-NH2. Half-life of GD monitored by solid-state NMR for MOFabric is 131 min versus 315 min on powder UiO-66-NH2.

  2. Sources and Impacts of Atmospheric NH3: Current Understanding and Frontiers for Modeling, Measurements, and Remote Sensing in North America (United States)

    Ammonia (NH3) contributes to widespread adverse health impacts, affects the climate forcing of ambient aerosols, and is a significant component of reactive nitrogen, deposition of which threatens many sensitive ecosystems. Historically, the scarcity of in situ measurements and th...

  3. Frailty Levels in Residential Aged Care Facilities Measured Using the Frailty Index and FRAIL-NH Scale. (United States)

    Theou, Olga; Tan, Edwin C K; Bell, J Simon; Emery, Tina; Robson, Leonie; Morley, John E; Rockwood, Kenneth; Visvanathan, Renuka


    To compare the FRAIL-NH scale with the Frailty Index in assessing frailty in residential aged care facilities. Cross-sectional. Six Australian residential aged care facilities. Individuals aged 65 and older (N = 383, mean aged 87.5 ± 6.2, 77.5% female). Frailty was assessed using the 66-item Frailty Index and the FRAIL-NH scale. Other measures examined were dementia diagnosis, level of care, resident satisfaction with care, nurse-reported resident quality of life, neuropsychiatric symptoms, and professional caregiver burden. The FRAIL-NH scale was significantly associated with the Frailty Index (correlation coefficient = 0.81, P care needs, with the Frailty Index having stronger associations with all of these measures. The FRAIL-NH scale is a simple and practical method to screen for frailty in residential aged care facilities. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  4. A photolabile linker for the solid-phase synthesis of 4-substituted NH-1,2,3-triazoles. (United States)

    Qvortrup, Katrine; Nielsen, Thomas E


    This communication presents the synthesis of a novel photolabile azidolinker based on the o-nitroveratryl group. The application of this linker for the synthesis and photolytic release of NH-1,2,3-triazoles is described.

  5. 77 FR 73650 - Electricity NH, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request... (United States)


    ...] Electricity NH, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Electricity...

  6. Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem model

    National Research Council Canada - National Science Library

    J. O. Bash; E. J. Cooter; R. L. Dennis; J. T. Walker; J. E. Pleim


    ...) Environmental Policy Integrated Climate (EPIC) agroecosystem model. The coupled CMAQ-EPIC model relies on EPIC fertilization timing, rate and composition while CMAQ models the soil ammonium (NH4...

  7. Sources and Impacts of Atmospheric NH3: Current Understanding and Frontiers for Modeling, Measurements, and Remote Sensing in North America (United States)

    Ammonia (NH3) contributes to widespread adverse health impacts, affects the climate forcing of ambient aerosols, and is a significant component of reactive nitrogen, deposition of which threatens many sensitive ecosystems. Historically, the scarcity of in situ measurements and th...

  8. Effects of NH3 annealing on interface and electrical properties of Gd-doped HfO2/Si stack

    Institute of Scientific and Technical Information of China (English)

    YANG Mengmeng; TU Hailing; DU Jun; WEI Feng; XIONG Yuhua; ZHAO Hongbin


    Effects of NH3 rapid thermal annealing (RTA) on the interface and electrical properties of Gd-doped HfO2 (GDH)/Si stack were investigated.The process of NH3 annealing could significantly affect the crystallization,stoichiometric properties of GDH film and the interface characteristic of GDH/Si system.NH3 annealing also led to the decrease of interface layer thickness.The leakage current density of Pt/GDH/p-Si MOS capacitor without RTA was 2× 10-3 A/cm2.After NH3 annealing,the leakage current density was about one order of magnitude lower (3.9×10-4 A/cm2).The effective permittivity extracted from the C-V curves was ~14.1 and ~13.1 for samples without and with RTA,respectively.

  9. Shape-Evolution Control of hybrid perovskite CH3NH3PbI3 crystals via solvothermal synthesis (United States)

    Zhang, Baohua; Guo, Fuqiang; Yang, Lianhong; Jia, Xiuling; Liu, Bin; Xie, Zili; Chen, Dunjun; Lu, Hai; Zhang, Rong; Zheng, Youdou


    We systematically synthesized CH3NH3PbI3 crystals using solvothermal process, and the reaction conditions such as concentration of the precursor, temperature, time, and lead source have been comprehensively investigated to obtain shape-controlled CH3NH3PbI3 crystals. The results showed that the CH3NH3PbI3 crystals exhibit tetragonal phase and the crystals change from nanoparticles to hopper-faced cuboids. Photoluminescence spectra of the crystals obtained with different lead sources show a blue shift due to the presence of defects in the crystals, and the peak intensity is very sensitive to the lead sources. Moreover, impurities (undesirable byproducts and excess components like HI or CH3NH2) presented during crystal growth can result in hopper growth.

  10. Rotational study of the NH{sub 3}–CO complex: Millimeter-wave measurements and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Surin, L. A., E-mail: [I. Physikalisches Institut, University of Cologne, Zülpicher Str. 77, 50937 Cologne (Germany); Institute of Spectroscopy, Russian Academy of Sciences, Fizicheskaya Str. 5, 142190 Troitsk, Moscow (Russian Federation); Potapov, A.; Schlemmer, S. [I. Physikalisches Institut, University of Cologne, Zülpicher Str. 77, 50937 Cologne (Germany); Dolgov, A. A.; Tarabukin, I. V.; Panfilov, V. A. [Institute of Spectroscopy, Russian Academy of Sciences, Fizicheskaya Str. 5, 142190 Troitsk, Moscow (Russian Federation); Kalugina, Y. N. [Department of Optics and Spectroscopy, Tomsk State University, 36 Lenin av., 634050 Tomsk (Russian Federation); Faure, A. [Université de Grenoble Alpes, IPAG, F-38000 Grenoble (France); CNRS, IPAG, F-38000 Grenoble (France); Avoird, A. van der, E-mail: [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)


    The rotational spectrum of the van der Waals complex NH{sub 3}–CO has been measured with the intracavity OROTRON jet spectrometer in the frequency range of 112–139 GHz. Newly observed and assigned transitions belong to the K = 0–0, K = 1–1, K = 1–0, and K = 2–1 subbands correlating with the rotationless (j{sub k}){sub NH3} = 0{sub 0} ground state of free ortho-NH{sub 3} and the K = 0–1 and K = 2–1 subbands correlating with the (j{sub k}){sub NH3} = 1{sub 1} ground state of free para-NH{sub 3}. The (approximate) quantum number K is the projection of the total angular momentum J on the intermolecular axis. Some of these transitions are continuations to higher J values of transition series observed previously [C. Xia et al., Mol. Phys. 99, 643 (2001)], the other transitions constitute newly detected subbands. The new data were analyzed together with the known millimeter-wave and microwave transitions in order to determine the molecular parameters of the ortho-NH{sub 3}–CO and para-NH{sub 3}–CO complexes. Accompanying ab initio calculations of the intermolecular potential energy surface (PES) of NH{sub 3}–CO has been carried out at the explicitly correlated coupled cluster level of theory with single, double, and perturbative triple excitations and an augmented correlation-consistent triple zeta basis set. The global minimum of the five-dimensional PES corresponds to an approximately T-shaped structure with the N atom closest to the CO subunit and binding energy D{sub e} = 359.21 cm{sup −1}. The bound rovibrational levels of the NH{sub 3}–CO complex were calculated for total angular momentum J = 0–6 on this intermolecular potential surface and compared with the experimental results. The calculated dissociation energies D{sub 0} are 210.43 and 218.66 cm{sup −1} for ortho-NH{sub 3}–CO and para-NH{sub 3}–CO, respectively.

  11. Evidence of amino acid precursors: C-N bond coupling in simulated interstellar CO2/NH3 ices (United States)

    Esmaili, Sasan


    Low energy secondary electrons are abundantly produced in astrophysical or planetary ices by the numerous ionizing radiation fields typically encountered in space environments and may thus play a role in the radiation processing of such ices [1]. One approach to determine their chemical effect is to irradiate nanometer thick molecular solids of simple molecular constituents, with energy selected electron beams and to monitor changes in film chemistry with the surface analytical techniques [2].Of particular interest is the formation of HCN, which is a signature of dense gases in interstellar clouds, and is ubiquitous in the ISM. Moreover, the chemistry of HCN radiolysis products such as CN- may be essential to understand of the formation of amino acids [3] and purine DNA bases. Here we present new results on the irradiation of multilayer films of CO2 and NH3 with 70 eV electrons, leading to CN bond formations. The electron stimulated desorption (ESD) yields of cations and anions are recorded as a function of electron fluence. The prompt desorption of cationic reaction/scattering products [4], is observed at low fluence (~4x1013 electrons/cm2). Detected ions include C2+, C2O2+, C2O+, CO3+, C2O3+ or CO4+ from pure CO2, and N+, NH+, NH2+, NH3+, NH4+, N2+, N2H+ from pure NH3, and NO+, NOH+ from CO2/NH3 mixtures. Most saliently, increasing signals of negative ion products desorbing during prolonged irradiation of CO2/NH3 films included C2-, C2H-, C2H2-, as well as CN-, HCN- and H2CN-. The identification of particular product ions was accomplished by using 13CO2 and 15NH3 isotopes. The chemistry induced by electrons in pure films of CO2 and NH3 and mixtures with composition ratios (3:1), (1:1), and (1:3), was also studied by X-ray photoelectron spectroscopy (XPS). Irradiation of CO2/NH3 mixed films at 22 K produces species containing the following bonds/functional groups identified by XPS: C=O, O-H, C-C, C-O, C=N and N=O. (This work has been funded by NSERC).

  12. Efficient and reproducible CH3NH3PbI(3-x)(SCN)x perovskite based planar solar cells. (United States)

    Chen, Yani; Li, Bobo; Huang, Wei; Gao, Deqing; Liang, Ziqi


    We report the addition of a small amount of Pb(SCN)2 into PbI2 in a two-step solution method. The resulting CH3NH3PbI(3-x)(SCN)x perovskite films present larger-sized crystals and fewer traps than CH3NH3PbI3. Their planar solar cells exhibit a maximum power conversion efficiency of 11.07% with remarkably high reproducibility and good stability.

  13. The Technology of Non-thermal Plasma Assisted NH3-SCR Reduce Marine Diesel Emission and Aldehydes Byproducts Formation

    Directory of Open Access Journals (Sweden)

    Lei Jiang


    Full Text Available This study describes briefly various after-treatment technologies in marine diesel engines and application difficulties of DPF and SCR are included. An experiment has been conducted using non-thermal plasma generated by Dielectric Barrier Discharge (DBD process assisted NH3-SCR catalyst to reduce the nitrogen oxides (NOx from diesel engine exhaust. The formation mechanism of byproducts-type such as HCHO and CH3CHO in the non-thermal plasma assisted NH3-SCR hybrid system.


    Institute of Scientific and Technical Information of China (English)

    CHENYi; LUJian-guo


    This paper introduces an application of "Aeration biological fluid tank"technology (ABFT) for the treatment of waste water containing NH4+-N and high concentrated chemicals.Highlights were focused on the effects of dissolved oxygen,pH,temperature and retention time on waste water bilogical treatment in order to find out a new approach in treatment of waste time on containing high concentrated NH4+-N.

  15. Immobilization of enzyme and antibody on ALD-HfO2-EIS structure by NH3 plasma treatment (United States)

    Wang, I.-Shun; Lin, Yi-Ting; Huang, Chi-Hsien; Lu, Tseng-Fu; Lue, Cheng-En; Yang, Polung; Pijanswska, Dorota G.; Yang, Chia-Ming; Wang, Jer-Chyi; Yu, Jau-Song; Chang, Yu-Sun; Chou, Chien; Lai, Chao-Sung


    Thin hafnium oxide layers deposited by an atomic layer deposition system were investigated as the sensing membrane of the electrolyte-insulator-semiconductor structure. Moreover, a post-remote NH3 plasma treatment was proposed to replace the complicated silanization procedure for enzyme immobilization. Compared to conventional methods using chemical procedures, remote NH3 plasma treatment reduces the processing steps and time. The results exhibited that urea and antigen can be successfully detected, which indicated that the immobilization process is correct.

  16. NH+4 Adsorption in a Eum-Orthic Anthrosol at Different Solution/Soil Ratios and Temperatures

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; ZHANG Yi-Ping


    Effects of NH4+ concentration,solution/soil ratio and temperature on NH4+ adsorption were studied in a Eum-Orthic Anthrosol. The slopes of the soil NH4+ adsorption isotherms and the fitted n,the coefficient for the adsorption intensity.and k,the coefficient related to adsorption capacity,of the Freundlich equation increased with increasing solution/soil ratio (SSR) and with decreasing temperature (T). For the range of experimental conditions,the value of (e)q/(e)c,the rate of change of the amount of NH4+ adsorbed in the soil solid phase (q) with respect to the equilibrium concentration of NH4+in soil solution (c),was 0.840,indicating that q increased with increasing c. From 2 to 45℃,(e)q/(e)SSR,the rate of change of q with respect to SSR,decreased from 2.598 to 1.996,showing that q increased with increasing SSR,while its increasing rate decreased with temperature. From SSR 1:1 to 20:1,(e)q/(e)T,the rate of change of q with respect to T,decreased from -0.095 to -0.36l,indicating that q decreased with increasing temperature,and at the same time the negative effect of temperature became larger as SSR increased. Thus under the experimental conditions the order of importance in determining the amount of NH4+ adsorbed in the soil solid phase was (e)q/(e)SSR>(e)q/(e)c>|(e)q/(e)T|,indicating that the greatest effect on the amount of NH4+ adsorbed was with the solution/soil ratio;the equilibrium concentration of NH4+had a lesser effect; and temperature had the least effect.

  17. First evidence on the validity and reliability of the Safety Organizing Scale-Nursing home version (SOS-NH) (United States)

    Ausserhofer, Dietmar; Anderson, Ruth A.; Colón-Emeric, Cathleen; Schwendimann, René


    Background The Safety Organizing Scale is a valid and reliable measure on safety behaviors and practices in hospitals. Purpose of the study This study aimed to explore the psychometric properties of the Safety Organizing Scale-Nursing Home version (SOS-NH). Design and Methods In a cross-sectional analysis of staff survey data, we examined validity and reliability of the 9-item Safety SOS-NH using American Educational Research Association guidelines. Subjects and Setting This sub-study of a larger trial used baseline survey data collected from staff members (n=627) in a variety of work roles in 13 NHs in North Carolina and Virginia, USA. Results Psychometric evaluation of the SOS-NH revealed good response patterns with low average of missing values across all items (3.05%). Analyses of the SOS-NH’s internal structure (e.g., comparative fit indices = 0.929, standardized root mean square error of approximation = 0.045) and consistency (composite reliability = 0.94) suggested its one-dimensionality. Significant between-facility variability, intraclass correlations, within-group agreement and design effect confirmed appropriateness of the SOS-NH for measurement at the NH level, justifying data aggregation. The SOS-NH showed discriminate validity from one related concept, communication openness. Implications Initial evidence regarding validity and reliability of the SOS-NH supports its’ utility in measuring safety behaviors and practices among a wide range of NH staff members, including those with low literacy. Further psychometric evaluation should focus on testing concurrent and criterion validity, using resident outcome measures (e.g., patient fall rates). PMID:23684122

  18. Oscillation in the Kmno 4NH 2CH 2COOHH 3PO 4 Cstr system (United States)

    Li, Hexing; Huang, Xiaojun; Deng, Jingfa


    A novel chemical oscillating reaction in the KMnO 4NH 2CH 2COOHH 3PO 4 CSTR system in the presence and absence of Ag + has been described. The reaction kinetics in a closed Mn0 4-NH 2CH 2COOHH 3PO 4 system has been analyzed and a possible mechanism has been proposed. The catalytic effect of Ag + in the above reaction has also been studied.

  19. First detection of ND in the solar-mass protostar IRAS16293-2422

    CERN Document Server

    Bacmann, A; Hily-Blant, P; Parise, B; Pagani, L; Bottinelli, S; Maret, S; Vastel, C; Ceccarelli, C; Cernicharo, J; Henning, T; Castets, A; Coutens, A; Bergin, E A; Blake, G A; Crimier, N; Demyk, K; Dominik, C; Gerin, M; Hennebelle, P; Kahane, C; Klotz, A; Melnick, G; Schilke, P; Wakelam, V; Walters, A; Baudry, A; Bell, T; Benedettini, M; Boogert, A; Cabrit, S; Caselli, P; Codella, C; Comito, C; Encrenaz, P; Falgarone, E; Fuente, A; Goldsmith, P F; Helmich, F; Herbst, E; Jacq, T; Kama, M; Langer, W; Lefloch, B; Lis, D; Lord, S; Lorenzani, A; Neufeld, D; Nisini, B; Pacheco, S; Pearson, J; Phillips, T; Salez, M; Saraceno, P; Schuster, K; Tielens, A G G M; van der Tak, F F S; van der Wiel, M H D; Viti, S; Wyrowski, F; Yorke, H; Faure, A; Benz, A; Coeur-Joly, O; Cros, A; Guesten, R; Ravera, L


    In the past decade, much progress has been made in characterising the processes leading to the enhanced deuterium fractionation observed in the ISM and in particular in the cold, dense parts of star forming regions such as protostellar envelopes. Very high molecular D/H ratios have been found for saturated molecules and ions. However, little is known about the deuterium fractionation in radicals, even though simple radicals often represent an intermediate stage in the formation of more complex, saturated molecules. The imidogen radical NH is such an intermediate species for the ammonia synthesis in the gas phase. Herschel/HIFI represents a unique opportunity to study the deuteration and formation mechanisms of such species, which are not observable from the ground. We searched here for the deuterated radical ND in order to determine the deuterium fractionation of imidogen and constrain the deuteration mechanism of this species. We observed the solar-mass Class 0 protostar IRAS16293-2422 with the heterodyne in...

  20. Rovibrational spectra of ammonia. II. Detailed analysis, comparison, and prediction of spectroscopic assignments for 14NH3, 15NH3, and 14ND3. (United States)

    Huang, Xinchuan; Schwenke, David W; Lee, Timothy J


    Several aspects of ammonia rovibrational spectra have been investigated using the new HSL-2 potential energy surface that includes an approximate correction for nonadiabatic effects. The unprecedented accuracy of rovibrational energy levels and transition energies computed using HSL-2 was demonstrated in Part I of this study. For (14)NH(3), new assignments for a few ν(3) + ν(4) band transitions and energy levels are suggested, and discrepancies between computed and HITRAN energy levels in the 2ν(4) band are analyzed (2ν(4) is the most difficult band below 5000 cm(-1)). New assignments are suggested for existing or missing 2ν(4) levels. Several new vibrational bands are identified from existing, unassigned HITRAN data, including 2ν(2) + ν(4), (ν(3) + ν(4)) -A(')∕A("), ν(1) + 2ν(2), and 2ν(2) + 2ν(4). The strong mixing between the 2ν(4) and 2ν(2) + ν(4) bands is carefully examined and found to be the source of the difficulties in the experimental modeling of 2ν(4). Discussion is presented for preliminary J = 10 results, where the overall root-mean-square error is estimated to be less than 0.039 cm(-1). The analysis of the 4ν(2) band demonstrates both the reliability and the accuracy of predictions from HSL-2. The full list of computed J = 0 band origins (with assignments) and the inversion splittings up to 7000-8000 cm(-1) above the zero-point energy are presented. J = 0-2 levels are reported for those bands below 5100 cm(-1) that are missing from the HITRAN database. For (15)NH(3), excellent agreement is found for the available ν(2) and ν(3) + ν(4)(E) transition energies, but significant deficiencies are shown for HITRAN levels and several corrections are suggested. The (15)N isotopic effects are presented for the J = 0-6 levels of 13 HITRAN bands. For (14)ND(3), we reproduce the pure rotational inversion spectra line frequencies with an accuracy similar to that for (14)NH(3). However, it is not possible to reproduce simultaneously all four

  1. Rovibrational spectra of ammonia. II. Detailed analysis, comparison, and prediction of spectroscopic assignments for 14NH3,15NH3, and 14ND3 (United States)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.


    Several aspects of ammonia rovibrational spectra have been investigated using the new HSL-2 potential energy surface that includes an approximate correction for nonadiabatic effects. The unprecedented accuracy of rovibrational energy levels and transition energies computed using HSL-2 was demonstrated in Part I of this study. For 14NH3, new assignments for a few ν3 + ν4 band transitions and energy levels are suggested, and discrepancies between computed and HITRAN energy levels in the 2ν4 band are analyzed (2ν4 is the most difficult band below 5000 cm-1). New assignments are suggested for existing or missing 2ν4 levels. Several new vibrational bands are identified from existing, unassigned HITRAN data, including 2ν2 + ν4, (ν3 + ν4) -A'/A'', ν1 + 2ν2, and 2ν2 + 2ν4. The strong mixing between the 2ν4 and 2ν2 + ν4 bands is carefully examined and found to be the source of the difficulties in the experimental modeling of 2ν4. Discussion is presented for preliminary J = 10 results, where the overall root-mean-square error is estimated to be less than 0.039 cm-1. The analysis of the 4ν2 band demonstrates both the reliability and the accuracy of predictions from HSL-2. The full list of computed J = 0 band origins (with assignments) and the inversion splittings up to 7000-8000 cm-1 above the zero-point energy are presented. J = 0-2 levels are reported for those bands below 5100 cm-1 that are missing from the HITRAN database. For 15NH3, excellent agreement is found for the available ν2 and ν3 + ν4(E) transition energies, but significant deficiencies are shown for HITRAN levels and several corrections are suggested. The 15N isotopic effects are presented for the J = 0-6 levels of 13 HITRAN bands. For 14ND3, we reproduce the pure rotational inversion spectra line frequencies with an accuracy similar to that for 14NH3. However, it is not possible to reproduce simultaneously all four pairs of inversion-split vibrational fundamentals to better than 0.05 cm-1

  2. 采用SrCl2-NH4Cl-NH3工质对的二级吸附式冷冻循环性能%Performance of two-stage adsorption freezing cycle with SrCl2-NH4Cl-NH3

    Institute of Scientific and Technical Information of China (English)

    罗伟莉; 王健; 王丽伟; 江龙; 金哲权; 王如竹


    吸附式制冷是一种绿色环保节能的制冷技术,在低于100℃的低品位热能如废热能、太阳能等的利用方面具有广阔的发展前景.为了能够利用这部分的能源,提出了由吸附制冷过程与再吸附过程组成的二级吸附式制冷循环.采用SrCl2 NH4Cl-NH3作为工质对,测试不同蒸发温度与冷却温度下吸附剂的吸附与解吸性能.实验测试结果表明:当热源温度为70℃时,二级吸附式制冷也能够实现-25℃下的冷量输出.在测试工况下,氯化锶的最大吸附量达到了理论吸附量的94%.80℃热源、25℃冷源以及25℃制冷条件下二级吸附式制冷循环的COP和SCP达到了0.250与160W· kg-1.这个数值与CaCl2-BaCl2-NH3两级冷冻在85℃驱动热源以及同等的冷源与制冷温度条件下的数据相对比,驱动热源需求降低了5℃,COP提高了4%,SCP提高了10%以上.%Adsorption refrigeration is an environmental benign and energy saving refrigeration technology and has a great potential for the utilization of low-grade energy, such as solar energy and industrial waste heat below 100°C.For efficient utilization of these low-temperature heat sources, a two-stage adsorption refrigeration cycle was proposed based on the adsorption refrigeration process and resorption process. Refrigeration performance of the working pair of SrCl2-NH4Cl-NH3 was tested at different evaporating and condensing temperatures. The results show that the two-stage adsorption refrigeration cycle can give the cooling output with the temperature of - 25°C when the temperature of the heat source is 70°C . The adsorption quantity of strontium chloride is 94% of the theoretical value. Under the condition of 80°C heat source, 25°C cooling source, and - 25°C refrigerating temperature, the COP and SCP are 0. 250 and 160 W ? Kg"1, respectively. At the same cooling and refrigerating temperatures, compared with the working pair of CaCl2-RaCl2-NH3 with the heat source

  3. Pseudohalide-induced moisture tolerance in perovskite CH3 NH3 Pb(SCN)2 I thin films. (United States)

    Jiang, Qinglong; Rebollar, Dominic; Gong, Jue; Piacentino, Elettra L; Zheng, Chong; Xu, Tao


    Two pseudohalide thiocyanate ions (SCN(-) ) have been used to replace two iodides in CH3 NH3 PbI3 , and the resulting perovskite material was used as the active material in solar cells. In accelerated stability tests, the CH3 NH3 Pb(SCN)2 I perovskite films were shown to be superior to the conventional CH3 NH3 PbI3 films as no significant degradation was observed after the film had been exposed to air with a relative humidity of 95 % for over four hours, whereas CH3 NH3 PbI3 films degraded in less than 1.5 hours. Solar cells based on CH3 NH3 Pb(SCN)2 I thin films exhibited an efficiency of 8.3 %, which is comparable to that of CH3 NH3 PbI3 based cells fabricated in the same way. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Origin of the 6.85 micron band near young stellar objects The ammonium ion (NH4+) revisited

    CERN Document Server

    Schutte, W A


    We have investigated whether the nu_4 feature of NH4+ is a viable candidate for the 6.85 micron absorption band seen towards embedded young stellar objects. To produce NH4+ astrophysical ice analogs consisting of H2O, CO2, NH3 and O2 were UV photolysed. The IR spectra reveal peaks that are identified with the NH4+, NO2-, NO3- and HCO3- ions. It is shown that the NH4+ matches two absorption features that are observed towards embedded young stellar objects, i.e., the strong 6.85 micron feature and the 3.26 micron feature. The characteristic redshift with temperature of the interstellar 6.85 micron feature is well reproduced. The abundance of NH4+ in interstellar ices would be typically 10 % relative to H2O. The experiments show that the counterions produce little distinct spectral signature but rather a pseudo-continuum if a variety of them is present in a H2O dominated environment. The anions could therefore go undetected in IR spectra of interstellar ice. In the ISM, where additional mechanisms such as surfac...

  5. Effect of NH4+-N/NO-3-N Ratios on Growth and Some Physiological Parameters of Chinese Cabbage Cultivars

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; LUO Jin-Kui; SHEN Qi-Rong


    The responses of three cultivars of Chinese cabbage (Brassica chinensis L.), one of the main vegetable crops in China,to different ratios of NH4+-N/NO-3-N was investigated to find the optimal ratio of ammonium to nitrate for maximal growth and to explore ways of decreasing the nitrate content, increasing nitrogen use efficiency of Chinese cabbage, and determining distributions of nitrogen and carbon. Three cultivars of Chinese cabbage were hydroponically grown with three different NH4+-N/NO-3-N ratios (0:100, 25:75 and 50:50). The optimal ratio of NH4+-N/NO-3-N for maximal growth of Chinese cabbage was 25:75. The increase in the ratio of NH4+-N/NO-3-N significantly decreased nitrate content in various tissues of Chinese cabbage in the order of petiole > leaf blade > root. The highest total nitrogen (N) content was found when the ratio of NH4+-N/NO-3-N was 25:75, and N contents in plant tissues were significantly different, mostly being in the order of leaf blade > petiole > root. At the NH4+-N/NO-3-N ratio of 25:75, the biomasses of Chinese cabbage nitrate and total nitrogen contents were lower. Thus, partial replacement of nitrate by ammonium could improve vegetable production by both increasing yields and decreasing nitrate content of the plants.

  6. Research on the chemical adsorption precursor state of CaCl2-NH3 for adsorption refrigeration

    Institute of Scientific and Technical Information of China (English)

    WANG; Liwei; WANG; Ruzhu; WU; Jingyi; WANG; Kai


    As a type of chemical adsorption working pair, the physical adsorption occurs first for CaCl2-NH3 because the effective reaction distance for van der Waals force is longer than that for chemical reaction force, and this physical adsorption state is named the precursor state of chemical adsorption. In order to get the different precursor states of CaCl2-NH3, the different distances between NH3 gas and Ca2+ are realized by the control of different phenomena of swelling and agglomeration in the process of adsorption. When the serious swelling exists while the agglomeration does not exist in the process of adsorption, experimental results show that the activated energy consumed by adsorption reaction increases for the reason of longer distance between Ca2+ and NH3, and at the same time the performance attenuation occurs in the repeated adsorption cycles. When the agglomeration occurs in the process of adsorption, the activated energy for the transition from precursor state to chemical adsorption decreases because the distance between NH3 gas and Ca2+ is shortened by the limited expansion space of adsorbent, and at the same time the performance attenuation does not occur. The adsorption refrigeration isobars are researched by the precursor state of chemical adsorption; results also show that the precursor state is a key factor for isobaric adsorption performance while the distribution of Ca2+ does not influence the permeation of NH3 gas in adsorbent.

  7. Initial atmospheric corrosion of zinc in presence of Na2SO4 and (NH4)2SO4

    Institute of Scientific and Technical Information of China (English)

    QU Qing; LI Lei; BAI Wei; YAN Chuan-wei


    Initial atmospheric corrosion of zinc in the presence of Na2SO4 and (NH4)2SO4 was investigated via quartz crystal microbalance(QCM) in laboratory at relative humidity(RH) of 80% and 25 °. The results show that both Na2SO4 and (NH4)2SO4 can accelerate the initial atmospheric corrosion of zinc. The combined effect of Na2SO4 and (NH4)2SO4 on the corrosion of zinc is greater than that caused by (NH4)2SO4 and less than that caused by Na2SO4. Fourier transform infrared spectroscopy(FTIR), X-ray diffractometry(XRD) and scanning electron microscopy(SEM) were used to characterize the corrosion products of zinc.(NH4)2Zn(SO4)2, Zn4SO4(OH)6·5H2O and ZnO present on zinc surface in the presence of (NH4)2SO4 while Zn4SO4(OH)6·5H2O and ZnO are the dominant corrosion products on Na2SO4-treated zinc surface. Probable mechanisms are presented to explain the experimental results.

  8. Importance of including ammonium sulfate ((NH42SO4 aerosols for ice cloud parameterization in GCMs

    Directory of Open Access Journals (Sweden)

    R. Yang


    Full Text Available A common deficiency of many cloud-physics parameterizations including the NASA's microphysics of clouds with aerosol-cloud interactions (hereafter called McRAS-AC is that they simulate lesser (larger than the observed ice cloud particle number (size. A single column model (SCM of McRAS-AC physics of the GEOS4 Global Circulation Model (GCM together with an adiabatic parcel model (APM for ice-cloud nucleation (IN of aerosols were used to systematically examine the influence of introducing ammonium sulfate (NH42SO4 aerosols in McRAS-AC and its influence on the optical properties of both liquid and ice clouds. First an (NH42SO4 parameterization was included in the APM to assess its effect on clouds vis-à-vis that of the other aerosols. Subsequently, several evaluation tests were conducted over the ARM Southern Great Plain (SGP and thirteen other locations (sorted into pristine and polluted conditions distributed over marine and continental sites with the SCM. The statistics of the simulated cloud climatology were evaluated against the available ground and satellite data. The results showed that inclusion of (NH42SO4 into McRAS-AC of the SCM made a remarkable improvement in the simulated effective radius of ice cloud particulates. However, the corresponding ice-cloud optical thickness increased even more than the observed. This can be caused by lack of horizontal cloud advection not performed in the SCM. Adjusting the other tunable parameters such as precipitation efficiency can mitigate this deficiency. Inclusion of ice cloud particle splintering invoked empirically further reduced simulation biases. Overall, these changes make a substantial improvement in simulated cloud optical properties and cloud distribution particularly over the Intertropical Convergence Zone (ITCZ in the GCM.

  9. NH4+浓度对黄色短杆菌XV0505发酵生产L-缬氨酸的影响%Effect of NH4+concentration on L-valine fermentation by Brevibacterium flavum XV0505

    Institute of Scientific and Technical Information of China (English)

    冯宁; 白亚磊; 徐庆阳; 谢希贤; 陈宁


    以L-缬氨酸(L-Val)生产菌黄色短杆菌XV0505为供试菌株,以(NH4)2SO4为唯一添加N源,考察不同NH4+浓度对发酵过程中菌体干质量、L-Val产量和葡萄糖消耗速率以及菌体内代谢流量的影响.研究表明:NH4+浓度过高或不足都会影响发酵水平,降低L-Val的产量.合适的初始NH4+浓度为225 mmol/L,产酸期NH4+维持浓度为35mmol/L时,有利菌体产酸.在此NH4+浓度下,在30L发酵罐发酵60h,发酵液中菌体生物量和L-Val质量浓度分别可达22.35和59.12g/L.%The ammonium sulfate was selected as the only feeding nitrogen source in the L-valine fermentation process by Brevibacterium flavum XV0505. Effects of different N H4+ concentrations on biomass,yield of L-valine,glucose consumption rate and the metabolic flux were studied in a 30 L fermentor. Results showed that excessive or insufficient concentrations of NH4+ would adversely affect the yield of L-valine and bacterial growth. Therefore,the appropriate additive dosage of NH4+ (225 mmol/l) was determined,and L-valine production was increased by keeping low NH4+ concentration(35 mmol/L) in the synthesis period of L-valine. With the optimum additional dosage of NH4+ , the yields of L-valine and DCW were up to 59. 12 and 22. 35 g/L (60 h) in the 30 L fermentor.

  10. Formation of TiN-encapsulated copper structures in a NH3 ambient (United States)

    Li, Jian; Mayer, J. W.; Shacham-Diamand, Y.; Colgan, E. G.


    A TiN-encapsulated copper structure was made by annealing a Cu-10 at. %Ti alloy film evaporated on a SiO2/Si(100) substrate at 550 °C in a NH3 ambient. A fast heating rate (70 °C/min) to 550 °C can effectively suppress the formation of Cu3Ti and enhance the TiNx formation near the surface of the copper film. Oxygen incorporation in the TiNx layer was found by Auger depth profiling measurement. This self-encapsulated Cu structure exhibits good adhesion to SiO2 and oxidation resistance.

  11. Pressure broadening of NH3 by H2 from 15 to 40 K (United States)

    Willey, Daniel R.; Timlin, Robert E.; Deramo, Melinda; Pondillo, Peter L.; Wesolek, Danielle M.; Wig, Ryan W.


    Pressure broadening of the (J,K)=(1,1), (2,2), and (3,3) inversion transitions of NH3 was measured using normal- H2 as the broadening agent at kinetic temperatures of 15 to 40 K. Measurements were taken in a quasiequilibrium cell using the collisional cooling technique. H2 pressure broadening cross sections were compared to low-temperature He pressure broadening of the same transitions and found to be from 2.5 to 8 times larger than corresponding He cross sections. Measured normal- H2 and He cross sections were also compared to calculated J=0, para-H2 cross sections.

  12. Functionalization of carbon nanotubes with -CH(n), -NH(n) fragments, -COOH and -OH groups. (United States)

    Milowska, Karolina Z; Majewski, Jacek A


    We present results of extensive theoretical studies concerning stability, morphology, and band structure of single wall carbon nanotubes (CNTs) covalently functionalized by -CH(n) (for n = 2,3,4), -NH(n) (for n = 1,2,3,4), -COOH, and -OH groups. These studies are based on ab initio calculations in the framework of the density functional theory. For functionalized systems, we determine the dependence of the binding energies on the concentration of the adsorbed molecules, critical densities of adsorbed molecules, global and local changes in the morphology, and electronic structure paying particular attention to the functionalization induced changes of the band gaps. These studies reveal physical mechanisms that determine stability and electronic structure of functionalized systems and also provide valuable theoretical predictions relevant for application. In particular, we observe that functionalization of CNTs causes generally their elongation and locally sp(2) to sp(3) rehybridization in the neighborhood of chemisorbed molecules. For adsorbants making particularly strong covalent bonds with the CNTs, such as the -CH2 fragments, we observe formation of the characteristic pentagon/heptagon (5/7) defects. In systems functionalized with the -CH2, -NH4, and -OH groups, we determine critical density of molecules that could be covalently bound to the lateral surface of CNTs. Our studies show that functionalization of CNTs can be utilized for band gap engineering. Functionalization of CNTs can also lead to changes in their metallic/semiconductor character. In semiconducting CNTs, functionalizing molecules such as -CH3, -NH2, -OH, -COOH, and both -OH and -COOH, introduce "impurity" bands in the band gap of pristine CNTs. In the case of -CH3, -NH2 molecules, the induced band gaps are typically smaller than in the pure CNT and depend strongly on the concentration of adsorbants. However, functionalization of semiconducting CNTs with hydroxyl groups leads to the metallization

  13. MIF-1 (Pro-Leu-Gly-NH2) decreases activity in Siamese fighting fish (Betta splendens). (United States)

    Brown, M M; Sardenga, P B; Olson, G A; Delatte, S W; Olson, R D


    The effects of MIF-1 (Pro-Leu-Gly-NH2) on activity and aggression of male Siamese Fighting Fish ( Betta splendens) were considered. Animals were given intraperitoneal injections of 0.0 or 10.0 mg/kg MIF-1. After a 10-minute delay, they were placed in a 10 gallon aquarium and their activity was monitored for 60 minutes. Although aggressive responses in the presence of suitable opponents were not reliably affected, as significant decrease in general activity was produced. This is compatible with differential effects of MIF-1 across species.

  14. Optically switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I3 (United States)

    Náfrádi, B.; Szirmai, P.; Spina, M.; Lee, H.; Yazyev, O. V.; Arakcheeva, A.; Chernyshov, D.; Gibert, M.; Forró, L.; Horváth, E.


    The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH3NH3(Mn:Pb)I3 material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low-power, light controlling magnetic devices.

  15. Theoretical analysis of static properties of mixed ionic crystal: NH4Cl1−Br

    Indian Academy of Sciences (India)

    D Rawat; N K Gaur; Sadhna Singh; A Gour


    In the present paper, we have investigated the static properties of the mixed ionic crystal NH4Cl1−Br using three-body potential model (TBPM) by the application of Vegard’s law. The results for the mixed crystal counterparts are also in fair agreement with the pseudo-experimental data generated from the application of Vegard’s law. The results for the end point members ( = 0 and 1) are in good agreement with the experimental data. The results on compressibility, molecular force constant, infrared absorption frequencies and Debye temperature are presented probably for the first time for these mixed crystal counterparts.

  16. Synthesis of Cu3N from CuO and NaNH2

    Directory of Open Access Journals (Sweden)

    Akira Miura


    Full Text Available We report on the low-temperature synthesis of submicron-sized Cu3N powder produced from CuO and NaNH2 powder mixture by heating at 150–190 °C in a Teflon-sealed autoclave. The structure was the anti-RuO3 type with a lattice parameter of 0.3814(1 nm, and strong optical absorption was observed below ∼1.9 eV. This synthesis method has the potential of facile control of the reaction with less use of ammonia sources.

  17. Mössbauer Study of Relaxation Phenomena in (NH4)3FeF6

    DEFF Research Database (Denmark)

    Mørup, Steen; Thrane, N.


    The shape of a relaxation-broadened Mössbauer absorption line for a paramagnetic ferric compound is influenced by various terms of the ionic Hamiltonian. Here we discuss especially how the application of an external magnetic field may influence the line shape and may give information about...... the magnitudes of other terms of the ionic Hamiltonian. Measurements on the two phases of (NH4)3FeF6 demonstrate differences between cubic and noncubic surroundings of the ferric ion. In the cubic phase we have found a temperature-independent spin-correlation time τ≃1.19×10-10 sec....

  18. Enantioselective Palladium-Catalyzed Carbene Insertion into the N-H Bonds of Aromatic Heterocycles. (United States)

    Arredondo, Vanessa; Hiew, Stanley C; Gutman, Eugene S; Premachandra, Ilandari Dewage Udara Anulal; Van Vranken, David L


    C3-substituted indoles and carbazoles react with α-aryl-α-diazoesters under palladium catalysis to form α-(N-indolyl)-α-arylesters and α-(N-carbazolyl)-α-arylesters. The products result from insertion of a palladium-carbene ligand into the N-H bond of the aromatic N-heterocycles. Enantioselection was achieved using a chiral bis(oxazoline) ligand, in many cases with high enantioselectivity (up to 99 % ee). The method was applied to synthesize the core of a bioactive carbazole derivative in a concise manner.

  19. Room-Temperature NH3 Gas Sensor Based on Hydrothermally Grown ZnO Nanorods

    Institute of Scientific and Technical Information of China (English)

    WEI Ang; WANG Zhao; PAN Liu-Hua; LI Wei-Wei; XIONG Li; DONG Xiao-Chen; HUANG Wei


    @@ A NH3 gas sensor based on a ZnO nanorod array is fabricated by hydrothermal decomposition on a Au electrode.The as-grown ZnO nanorods have uniform diameter distribution and good crystal structure,shown by scanning electron microscopy,x-ray diffraction,high resolution transmission electron microscopy and photoluminescence emission characterizations.The gas sensing results show that the ZnO nanorod-based device responds well to ammonia gas at room temperature(sensitivity S is about 8).

  20. Dispersal of dense protostellar material - NH3 hot cores and outflows in Sagittarius B2

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, S.N.; Genzel, R.; Palmer, P.


    VLA observations of Sgr B2 in six ammonia transitions have uncovered two 200-K condensations with approximately 0.2 pc diameters associated with water maser sources which are similar to the Orion hot core but are more massive. Total NH3 mass of the northern source is 1000 times higher than in the Orion hot core. The hot core emission traces dense gas around newly formed massive stars, and is produced during a relatively brief stage after the star begins to heat the surrounding medium and before the dense gas is dispersed by outflow and the emergence of an expanding H II region. 36 references.

  1. Fe-BEA Zeolite Catalysts for NH3-SCR of NOx

    DEFF Research Database (Denmark)

    Frey, Anne Mette; Mert, Selcuk; Due-Hansen, Johannes


    Iron-containing zeolites are known to be promising catalysts for the NH3-SCR reaction. Here, we will investigate the catalytic activity of iron-based BEA catalysts, which was found to exhibit improved activities compared to previously described iron-containing zeolite catalysts, such as ZSM-5...... and ZSM-12. Series of Fe-BEA zeolite catalysts were prepared using a range of different preparation methods. Furthermore, we found that an iron concentration around 3 wt% on BEA showed a small optimum in SCR activity compared to the other iron loadings studied....

  2. 美国ECM重磅推出新产品快速NOx/NH3分析仪5240

    Institute of Scientific and Technical Information of China (English)



  3. Enhanced performance of CH3NH3PbI3-x Cl x perovskite solar cells by CH3NH3I modification of TiO2-perovskite layer interface. (United States)

    Wang, Wen; Zhang, Zongbao; Cai, Yangyang; Chen, Jinshan; Wang, Jianming; Huang, Riyan; Lu, Xubing; Gao, Xingsen; Shui, Lingling; Wu, Sujuan; Liu, Jun-Ming


    In this work, perovskite solar cells (PSCs) with CH3NH3PbI3-x Cl x as active layer and spiro-OMeTAD as hole-transport media have been fabricated by one-step method. The methylammonium iodide (CH3NH3I) solution with different concentrations is used to modify the interface between mesoporous TiO2 (meso-TiO2) film and CH3NH3PbI3-x Cl x perovskite layer. Several techniques including X-ray diffraction, scanning electron microscopy, optical absorption, electrochemical impedance spectroscopy (EIS) and photoluminescence are used to investigate the effect of the interfacial modification. It is found that the interfacial modification by CH3NH3I enhance the crystallinity and increase the grain size of CH3NH3PbI3-x Cl x layer, and improve the surface wetting properties of perovskite precursor on meso-TiO2 film. The sunlight absorption and external quantum efficiency of PSCs in the visible region with wavelength less than 600 nm have been improved. The Nyquist plots obtained from the EIS suggest that the CH3NH3I modification can reduce the charge recombination rates. The photoluminescence measurement shows that the exciton dissociation in the modified devices is more effective than that in the control samples. The photovoltaic performance of the modified devices can be significantly improved with respect to the reference (control) devices. The CH3NH3I modified devices at the optimized concentration demonstrate the average power conversion efficiency of 12.27 % in comparison with the average efficiency of 9.68 % for the reference devices.

  4. Evaluation of the phase composition of (NH{sub 4}){sub 2}SO{sub 4} + (NH{sub 4})H{sub 2}PO{sub 4} mixtures by X-ray diffractometry

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Angel L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Escuela de Ingenierias Industriales, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail:; Cumbrera, Francisco L. [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Perez, Jose; Vas, Beatriz del; Perez, Eduardo [Departamento de Ingenieria Minera, Geologica y Cartografica, Area de Quimica Inorganica, Universidad Politecnica de Cartagena, Cartagena (Murcia) (Spain)


    The phase composition of standard (NH{sub 4}){sub 2}SO{sub 4} + (NH{sub 4})H{sub 2}PO{sub 4} mixtures was investigated by X-ray diffractometry (XRD) using the internal-standard, reference-intensity-ratio, and Rietveld methods. It was found that the Rietveld method yields the most accurate phase-composition measurements, with an average error of {approx}2 wt.%. It was also found that the internal-standard method is only effective in determining the phase composition if the calibration curve for (NH{sub 4})H{sub 2}PO{sub 4} is used, giving an average error of {approx}6.5 wt.%. On the contrary, the internal-standard method with the calibration curve of the (NH{sub 4}){sub 2}SO{sub 4} phase and the reference-intensity-ratio method are not valid. The inappropriateness of these two methods was attributed to graininess in the (NH{sub 4}){sub 2}SO{sub 4} phase, with the attendant deviation of its diffracted intensities from the theoretical values. Direct scanning electron microscopy observations of the morphology of the powder particles in the mixtures showed clear evidence of the large agglomerates formed because the individual powder particles are partially sintered together during milling, thus corroborating the graininess determined by the XRD analyses. Finally, the implications of the present study for the quantitative phase-composition analysis of (NH{sub 4}){sub 2}SO{sub 4} + (NH{sub 4})H{sub 2}PO{sub 4} mixtures, which are of great technological importance for the fire prevention industry, are discussed.

  5. Mg(BH4)2-NaNH2体系的加热放氢性能研究%Dehydrogenation Property of Mg(BH4)2-NaNH2 Composites

    Institute of Scientific and Technical Information of China (English)

    褚海亮; 张湛; 黄建灵; 邱树君; 邹勇进; 向翠丽; 张焕芝; 徐芬; 孙立贤


    采用机械球磨法制备了Mg(BH4) 2-NaNH2复合储氢材料,研究了Mg(BH4)2和NaNH2之间的相互作用及其加热放氢性能.当物质的量比为1:2时,Mg(BH4)2与NaNH2之间发生反应:Mg(BH4)2+2NaNH2→2NaBH4 +Mg(NH2)2.当物质的量比为1:1时,Mg (BH4)2与NaNH2之间发生反应:Mg(BH4)2+NaNH2→NaBH4+MgBNH6.加热到400℃,该样品分两步进行放氢反应,放氢峰温分别在190℃和369℃,可以放出4.7%(质量分数)氢气.第一步放氢反应为MgBNH6分解产生MgH2,即:MgBNH6--MgH2 +BN+ 2H2.第二步放氢反应为MgH2的分解:MgH2→Mg+H2.

  6. Enhanced performance of CH3NH3PbI3- x Cl x perovskite solar cells by CH3NH3I modification of TiO2-perovskite layer interface (United States)

    Wang, Wen; Zhang, Zongbao; Cai, Yangyang; Chen, Jinshan; Wang, Jianming; Huang, Riyan; Lu, Xubing; Gao, Xingsen; Shui, Lingling; Wu, Sujuan; Liu, Jun-Ming


    In this work, perovskite solar cells (PSCs) with CH3NH3PbI3- x Cl x as active layer and spiro-OMeTAD as hole-transport media have been fabricated by one-step method. The methylammonium iodide (CH3NH3I) solution with different concentrations is used to modify the interface between mesoporous TiO2 (meso-TiO2) film and CH3NH3PbI3- x Cl x perovskite layer. Several techniques including X-ray diffraction, scanning electron microscopy, optical absorption, electrochemical impedance spectroscopy (EIS) and photoluminescence are used to investigate the effect of the interfacial modification. It is found that the interfacial modification by CH3NH3I enhance the crystallinity and increase the grain size of CH3NH3PbI3- x Cl x layer, and improve the surface wetting properties of perovskite precursor on meso-TiO2 film. The sunlight absorption and external quantum efficiency of PSCs in the visible region with wavelength less than 600 nm have been improved. The Nyquist plots obtained from the EIS suggest that the CH3NH3I modification can reduce the charge recombination rates. The photoluminescence measurement shows that the exciton dissociation in the modified devices is more effective than that in the control samples. The photovoltaic performance of the modified devices can be significantly improved with respect to the reference (control) devices. The CH3NH3I modified devices at the optimized concentration demonstrate the average power conversion efficiency of 12.27 % in comparison with the average efficiency of 9.68 % for the reference devices.

  7. Measuring Turbulence in the Interstellar Medium by Comparing N(H I; Lyα) and N(H I; 21 cm) (United States)

    Wakker, Bart P.; Lockman, Felix J.; Brown, Jonathan M.


    We present a study of the small-scale structure of the interstellar medium (ISM) in the Milky Way. We used HST STIS data to measure N(H I) in a pencil beam toward 59 active galactic nuclei and compared the results with the values seen at 9'-36' resolution in the same directions using radio telescopes (Green Bank Telescope, Green Bank 140-ft, and LAB survey). The distribution of ratios N(Lyα)/N(H I) has an average of 1 and a dispersion of about 10%. Our analysis also revealed that spectra from the Leiden-Argentina-Bonn (LAB) all-sky H I survey need to be corrected, taking out a broad Gaussian component (peak brightness temperature 0.048 K, FWHM 167 km s-1, and central velocity -22 km s-1). The column density ratios have a distribution showing similarities to simple descriptions of hierarchical structure in the neutral ISM as well as to a more sophisticated three-dimensional magnetohydrodynamic simulation. From the comparison with such models, we find that the sonic Mach number of the local ISM should lie between 0.6 and 0.9. However, none of the models yet matches the observed distribution in all details, but with many more sightlines (as will be provided by the Cosmic Origins Spectrograph) our approach can be used to constrain the properties of interstellar turbulence.

  8. Soil NH+4 Fixation and Fertilizer N Recovery as Affected by Soil Moisture and Fertilizer Application Methods

    Institute of Scientific and Technical Information of China (English)

    TONG Yah-An; O.EMTERYD; H.GRIP; LU Dian-Qing


    Ammonium fixation and the effects of soil moisture and application methods on fertilizer N recovery were investigated in two soils of Shaanxi Province,China,a Luvisol and an Entisol,through two experiments performed in the laboratory and in a glass shelter,respectively,by using ammonium bicarbonate (NH4HCO3). The laboratory closed incubation box experiment was conducted using the Luvisol to study NH4+ fixation rate at soil moisture levels of 10.1%,22.7% and 35.3% water filled pore space (WFPS). The fixed NH4+-N increased dramatically to 51% and 66%,67% and 74%,and 82% and 85% 1,2 and 36 h after fertilizer incorporation at moisture levels of 10.1% and 22.7% WFPS and 35.3%WFPS,respectively. The rapid NH4+ fixation rates at all moisture levels could help prevent NH4+ losses from ammonia volatilization. In the glass shelter pot experiment,N fertilizer was applied by either banding (in a concentrated strip)or incorporating (thoroughly mixing) with the Entisol and the Luvisol. An average of 74.2% of the added N fertilizer was recovered 26 days after application to the Luvisol,while only 61.4% could be recovered from the Entisol,due to higher NH4+ fixation capacity of the Luvisol. The amount of fixed NH4+ decreased with increasing WFPS. The amount of fixed NH4+ in the incorporated fertilizer treatment was,on average,10% higher than that in the banded treatment.Higher NH4+ fixation rates could prevent N loss and thus increase N recovery. The results from the Luvisol showed lower nitrogen recovery as soil moisture level increased,which could be explained by the fact that most of the fixed NH4+ was still not released when the soil moisture level was low. When the fertilizer was incorporated into the soil,the recovery of N increased,compared with the banded treatment,by an average of 26.2% in the Luvisol and 11.2% in the Entisol,which implied that when farmers applied fertilizer,it would be best to mix it well with the soil.


    Directory of Open Access Journals (Sweden)



    Full Text Available On allowing (Cy2NH22C2O4∙2H2O to react with SnBu3Cl or SnMe3Cl, i-Bu2NH2HC2O4 with SnBu3Cl, (Bu2NH22C2O4 with SnMe3Cl, (i-Bu2NH22C2O4 with SnPh2Cl2, a mixture of i-Bu2NH22C2O4 and (Me4N2C2O4 with SnPh2Cl2, (Pr2NH22C2O4 with SnPh3Cl, the oxalato derivatives and complexes Cy2NH2C2O4SnBu3.3H2O∙1/4Cy2NH2Cl, i-Bu2NH2C2O4SnBu3∙1/2(i-Bu2NH22C2O4,y2NH2C2O4SnMe3∙1/2(Cy2NH22C2O4, Sn(C2O42∙[C2O4(SnMe3∙H2O2]∙2EtOH∙1/4[(Bu2NH22C2O4],(i-Bu2NH22 C2O4∙ 2SnPh2Cl2∙SnCl4∙4(i-Bu2NH2OH∙2(i-Bu2NH2Cl, 2[SnPh2Cl4(i-Bu2NH22]∙ SnCl2C2O4∙4i-Bu2NH2Cl and 2[Pr2NH2C2O4SnPh3]∙(Pr2NH22C2O4∙SnCl4∙ 2Pr2NH2Cl were obtained. Double chain, two metallic components and a dimeric structures are suggested with trans coordinated SnMe3 residues, these chains being connected through R2NH2+ (R = Cy, i-Bu only or by (R2NH22C2O4 bridges. The oxalate behaves as a monochelating, a bridging, an only hydrogen bonding involved or monodentate and H bond involved ligand. The environments around the tin (IV centres are cis or trans trigonal bipyramidal, tetrahedral or octahedral. Supramolecular architectures may be obtained when extra hydrogen bonds are possible.

  10. The N(H2/I(CO Conversion Factor: A Treatment that Includes Radiative Transfer

    Directory of Open Access Journals (Sweden)

    W. F. Wall


    Full Text Available Se presenta un tratamiento que explica mejor el factor de conversión N(H2=I(CO y que incluye la transferencia radiativa. A primera vista, incluir la transferencia radiativa parece superfluo para una línea óptimamente gruesa como CO J = 1 0. No obstante, dado que el medio interestelar es inhomogéneo, los fragmentos de gas (es decir, grumos todavía pueden ser óptimamente delgadas hacia sus bordes y en las alas de los pérfiles de la línea. El tratamiento estadístico de Martin et al. (1984 de la transferencia radiativa a través una nube molecular con grumos se usa para derivar una expresión para el factor de conversión que su- pera los defectos de las explicaciones más tradicionales basadas en Dickman et al. (1986. Por un lado, el tratamiento presentado aquí posiblemente representa un avance importante al entender el factor de conversión N(H2=I(CO pero, por otro lado, tiene sus propios defectos, que son discutidos aquí brevemente.

  11. Modifying CH3NH3PbBr3 nanocrystals with arylamines (United States)

    Zhu, Ruimin; Liu, Heyuan; Shen, Li; Sun, Dejun; Li, Xiyou


    Chemically decorating CH3NH3PbBr3 with a group of para-substituted arylamine (R-An) was investigated, where R ranges from electron-withdrawing trifluoromethoxy(-CF3O), to hydrogen or electron-donating ethoxy (-EtO). Different ratios of R-An ammonium bromide and methylammonium bromide (MA) (R-An/MA=3/7, 4/6, 5/5, 6/4 and 7/3) were tested. XRD patterns revealed that the perovskite nanocomposite were cubic with good crystallinity. TEM and photoluminescence suggested that the perovskite nanocrystals were composed of 2D layered and 3D bulk structures. 1H NMR and TGA experiments revealed that the non-substituted aniline can readily adsorb to the surface of perovskite at any ratios between R-An and MA. But an EtOAn/MA ratio ≥1 is needed to anchor the EOAn molecules on the surface of perovskite. For the arylamine with the electron-withdrawing -CF3O group, it cannot adsorb to the surface of the perovskite at any concentrations. This result reveals that both steric hindrance and alkalinity can affect the anchoring of arylamine on the surface of CH3NH3PbBr3 perovskite. I-V curves of the perovskite nanocrystal films prepared by spin coating suggest that proper surface modification can increase the conductivity significantly.

  12. A Study of SDT in an Ammonium Nitrate (NH4 NO3) Based Granular Explosive (United States)

    Burns, Malcolm; Taylor, Peter


    In order to study the SDT process in a granular non ideal explosive (NIE) an experimental technique has been developed that allows the granular explosive to be shock initiated at a well controlled ``tap density''. The granular NIE was contained in a PMMA cone and a planar shock was delivered to the explosive through buffer plates of varying material. A combination of piezoelectric probes, ionization pins, PVDF stress gauges and a high speed framing camera were used to measure the input shock pressure and shock and detonation wave positions in the explosive. Four trials were performed to characterize the run to detonation distance versus pressure relationship (Pop plot) of the granular NH4 NO3 explosive. Input pressures ranged from close to the 4GPa predicted CJ pressure of the granular explosive down to 1.4 GPa, giving run distances up to 14mm for the lowest pressure. The data indicates a steady acceleration of the input shock to the detonation velocity, implying significant reaction growth at the shock front. This is in contrast to the behaviour of most high density pressed PBXs which show little growth in shock front velocity before transit to detonation. The experimentally observed initiation behaviour is compared to that predicted by a simple JWL++ reactive burn model for the granular NH4 NO3 explosive which has been fitted to other detonics experiments on this material.

  13. Plasma nitridation of silicon by N2 and NH3 in PECVD reactor (United States)

    Bakardjieva, V. S.; Alexieva, Z. I.; Beshkov, G. D.; Mateev, E. S.


    The effect was investigated of nitrogen and ammonia plasma treatment of monocrystalline Si wafers. The experiments were carried out in a plasma-enhanced chemical vapor deposition reactor. The wafers were subjected to N2 and NH3 plasma treatment for varying times at temperature of 380 °C. The plasma treated surfaces were studied by transmission electron microscopy with C-Pt replicas, reflection high-energy electron diffraction and Auger electron spectroscopy. The results point to the growth of an amorphous layer on the surface. The Auger electron spectroscopy depth profiles obtained by sputtering show the presence of an oxynitride layer with varying composition depending on the time of plasma treatment. The Auger electron spectroscopy analysis shows that after 60 s of treatment in N2 plasma, the nitrogen content is 8 at.%, while after 300 s it is 22 at.%, the thickness of the oxynitride nanolayer being 2.5-7.2 nm. In the case of NH3 plasma the thickness calculated from the sputtering time (from 50 s to 15 min) varies between 2 and 12 nm, and the nitrogen content, between 5 and 35 at.%.

  14. H2 assisted NH3-SCR over Ag/Al2O3 for automotive applications

    DEFF Research Database (Denmark)

    Fogel, Sebastian

    The up-coming strict emission legislation demands new and improved catalysts for diesel vehicle deNOx. The demand for low-temperature activity is especially challenging. H2-assisted NH3-SCR over Ag/Al2O3 has shown a very promising low-temperature activity and a combination of Ag/Al2O3 and Fe...... has been the preparation of monolithic catalyst bricks for the catalyst testing. A high SBET and higher Ag loading gave a high sulphur tolerance and activity. It was believed that the high SBET is needed to give a higher NH3 adsorption capacity, necessary for the SCR reaction. A higher Ag loading...... both in a sequential dual-bed layout and a dual-layer layout where the catalysts were coated on top of each other. The Ag/Al2O3 catalyst was also investigated with the aim of improving the sulphur tolerance and low-temperature activity by testing different alumina-supports. A large focus of this study...

  15. Preparation and characterization of Pd/C catalyst obtained in NH 3-mediated polyol process (United States)

    Li, Huanqiao; Sun, Gongquan; Jiang, Qian; Zhu, Mingyuan; Sun, Shiguo; Xin, Qin

    Vulcan XC-72R carbon supported Pd nanoparticles was obtained in a NH 3-mediated polyol process without any protective agent and characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. The added NH 3 species is found to have a strong complex ability to Pd, which not only avoids the formation of Pd hydroxide precipitate resulted from Pd hydrolysis, but also restrains the further complete reduction of Pd. Temperature-programmed reduction equipped with a mass spectrometry (TPR-MS) is employed to study the reductive behavior of unreduced Pd complex in Pd/C catalyst and the results show that the post-treatment in a reductive atmosphere at higher temperature is needed to ensure the complete reduction of Pd. XRD patterns show the heat-treated Pd/C sample in a reductive atmosphere has a face centered cubic crystal structure and TEM image indicates that the dispersion of Pd nanoparticles on the carbon support is uniform and in a narrow particle size range. Thermodynamic data analysis is carried out to elucidate the possible reaction pathway for the preparation of Pd/C catalyst in this process. The obtained Pd/C catalyst shows high activity to formic acid oxidation and high selectivity to oxygen reduction reaction (ORR) with the presence of methanol.

  16. Charge-assisted bond N(+)H mediates the gelation of amorphous lurasidone hydrochloride during dissolution. (United States)

    Qian, Shuai; Wang, Shanshan; Li, Zhen; Wang, Xiaojie; Ma, Di; Liang, Shujun; Gao, Yuan; Zhang, Jianjun; Wei, Yuanfeng


    Lurasidone hydrochloride (LH), the hydrochloride form of lurasidone with a charge-assisted bond N(+)H, is an atypical antipsychotropic agent for the treatment of schizophrenia. As a BCS class II drug, LH has a low oral bioavailability mainly due to its poor water solubility and low dissolution. In order to improve its solubility, amorphization of LH was performed and characterized. Unexpectedly, the dissolution rate of amorphous LH was much lower than that of crystalline LH. In addition, the amorphous LH powders quickly aggregated when contacting the dissolution media (water, 37°C), and formed a sticky gel adhering on the paddle. The follow-up polarized light microscope, XRPD, DSC, and FTIR analysis found that amorphous LH transformed to crystalline LH during dissolution. On the other hand, no such gelation phenomenon of amorphous lurasidone was observed under the same dissolution condition. However, the gel would reform when dropping concentrated hydrochloric acid slowly into the bottom of the medium during the dissolution of amorphous lurasidone, and XRPD/DSC/FTIR results indicated that the regenerated gel was consisted of crystalline LH, suggesting that the charge-assisted bond N(+)H in the structure of LH mediated the gel formation of amorphous LH during its dissolution process.

  17. Outdoor-indoor air quality in Riyadh: SO2, NH3, and HCHO. (United States)

    Al-Rehaili, A M


    A funded research project was conducted during the period July 1992 through November 1994. The project was designed to evaluate indoor and ambient air quality in and around buildings of different types and uses in Riyadh, the capital of Saudi Arabia. Thirty intercity buildings and two outercity (background) sites were carefully selected and monitored for air quality. Ten air pollutants, together with relevant meteorological parameters, were monitored indoor and outdoor at each site continuously and simultaneously for a period of two weeks covering summer and winter seasons. This article discusses the results obtained for sulfur dioxide (SO2), ammonia (NH3) and formaldehyde (HCHO). Results of this investigation revealed that most sites had on the average exceeded the recommended standards for SO2 and NH3 both indoor and outdoor, with indoor levels being worse than outdoor during winter time. Several sites also showed high levels of HCHO, with outdoor levels being consistently higher than indoor. Statistical and frequency analyses were performed on the collected data, showing seasonal and sector by sector variability, and outdoor-indoor correlations.

  18. Exploring High-Velocity NH_3(6,6) Emission at the Center of our Galaxy

    CERN Document Server

    Donovan, J L; Ho, P T P; Donovan, Jennifer L.; Herrnstein, Robeson M.; Ho, Paul T.P.


    Using the NH\\3 (6,6) transition, which samples dense ($\\sim 10^{5}$) molecular gas with an energy above ground of 412 K, we find hot gas at high velocities (--142 to --210 km s$^{-1}$) associated with the central 2 pc of the Galactic center. This material may be either infalling gas due to shocks or tidal stripping, or possibly gas swept from the nuclear region. We identify two high-velocity features, which we call the Southern Runner and the Cap, and correlate these features with others detected in various molecular observations of the Galactic center. The characteristic linewidths of the Southern Runner and Cap, 10 -- 15 \\kms, are similar to those of other hot Galactic center clouds. The estimated H$_{2}$ masses of these clouds are 4$\\times 10^{3}$ M$\\sol$ and 2$\\times 10^{3}$ M$\\sol$, consistent with the masses of the western streamer and northern ridge, NH\\3 (6,6) emission features detected within the central 10 pc at lower velocities. Three possible explanations for this emission are discussed assuming t...

  19. Carbon nanotubes loaded with vanadium oxide for reduction NO with NH3 at low temperature☆

    Institute of Scientific and Technical Information of China (English)

    Shuli Bai; Shengtao Jiang; Huanying Li; Yujiang Guan


    The catalytic activity of carbon nanotubes-supported vanadium oxide (V2O5/CNTs) catalysts in the selective catalytic reduction (SCR) of NO with NH3 at low temperatures (≤250 °C) was investigated. The effects of V2O5 loading, reaction temperature, and presence of SO2 on the SCR activity were evaluated. The results show that V2O5/CNTs catalysts exhibit high activity for NO reduction with NH3 at low-temperatures. The catalysts also show very high stability in the presence of SO2. More interestingly, their activities are significantly promoted in-stead of being poisoned by SO2. The promoting effect of SO2 is distinctly associated with V2O5 loading, particularly maximized at low V2O5 loading, which indicated the role of CNTs support in this effect. The promoting effect of SO2 at low temperatures suggests that V2O5/CNTs catalysts are promising catalytic materials for low-temperature SCR reactions.

  20. Study on novel and promising NH3-SCR catalysts on glass fiber cloth for industrial applications (United States)

    Xie, Junlin; Li, Fengxiang; Hu, Hua; Qi, Kai; He, Feng; Fang, De


    MnO x , Mn/TiO2 and Fe-Mn/TiO2 catalysts were prepared by precipitation-impregnation method. The MnO x catalyst shows the highest activity for the reduction of NO with NH3 at the temperature range of 80 °C to 140 °C, and achieves more than 98% of NO conversion at 140 °C. The MnO x catalyst loaded on glass fiber cloth (GFC) was prepared by impregnation method, and the effects of preparation conditions were studied. It turns out that the catalyst particle size, loading capacity and catalyst varieties make a great difference to catalytic performance. In addition, the catalyst with aluminum sol as a binder has the higher catalytic activity but poor ability of anti-sulfur and anti-water poisoning, compared with the catalyst using silica sol binder. Further, MnO x , Mn/TiO2 and Fe-Mn/TiO2 powders were loaded onto GFC using XRD, HRTEM, TGA, SEM, BET, H2-TPR and NH3-TPD to systematically characterize the various physico-chemical properties and denitrition activity. The results indicate that the changes of active components, specific surface area, microstructure, reducibility and suface acidity of the three kinds of catalysts lead to different catalytic activities.

  1. Effects of NO2 and NH3 from road traffic on epiphytic lichens. (United States)

    Frati, L; Caprasecca, E; Santoni, S; Gaggi, C; Guttova, A; Gaudino, S; Pati, A; Rosamilia, S; Pirintsos, S A; Loppi, S


    The results of a survey aimed at investigating whether NO2 and NH3 emitted by road traffic can influence lichen diversity, lichen vitality and the accumulation of nitrogen in lichen thalli are reported. For this purpose, distance from a highway in a rural environment of central Italy was regarded as the main parameter to check this hypothesis. The results of the present survey indicated that road traffic is not a relevant source of NH3. On the other hand, NO2 concentrations, although rather low, were negatively correlated with distance from the highway according to a typical logarithmic function. No association between NO2 concentrations and the diversity of epiphytic lichens was found, probably because of the low NO2 values measured. Also bark properties were not influenced by distance from the highway. Accumulation of nitrogen, reduction in the content of chlorophyll a, chlorophyll b and total carotenoids were found in transplanted thalli of Evernia prunastri, but NO2 was not responsible for these changes, which were probably caused by applications of N-based fertilizers.

  2. Effective NH{sub 2}-grafting on attapulgite surfaces for adsorption of reactive dyes

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Ailian [College of Chemistry and Chemical Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, Jiangsu Province (China); School of Chemistry and Chemical Engineering, Huaiyin Normal University, Key Lab for Chemistry of Low-Dimensional Materials of Jiangsu Province, No. 111 Changjiang West Road, Huaian 223300, Jiangsu Province (China); Zhou, Shouyong; Zhao, Yijiang [School of Chemistry and Chemical Engineering, Huaiyin Normal University, Key Lab for Chemistry of Low-Dimensional Materials of Jiangsu Province, No. 111 Changjiang West Road, Huaian 223300, Jiangsu Province (China); Lu, Xiaoping, E-mail: [College of Chemistry and Chemical Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, Jiangsu Province (China); Han, Pingfang [College of Chemistry and Chemical Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, Jiangsu Province (China)


    Highlights: {yields} We prepared a new amine functionalized adsorbent derived from clay-based material. {yields} Attapulgite surface was modified with 3-aminopropyltriethoxysilane. {yields} Some modification parameters affecting the adsorption potential were investigated. {yields} Enhance the attapulgite adsorptive capacity for reactive dyes from aqueous solutions. - Abstract: The amine moiety has an important function in many applications, including, adsorption, catalysis, electrochemistry, chromatography, and nanocomposite materials. We developed an effective adsorbent for aqueous reactive dye removal by modifying attapulgite with an amino-terminated organosilicon (3-aminopropyltriethoxysilane, APTES). Surface properties of the APTES-modified attapulgite were characterized by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption. We evaluated the impact of solvent, APTES concentration, water volume, reaction time, and temperature on the surface modification. NH{sub 2}-attapulgite was used to remove reactive dyes in aqueous solution and showed very high adsorption rates of 99.32%, 99.67%, and 96.42% for Reactive Red 3BS, Reactive Blue KE-R and Reactive Black GR, respectively. These powerful dye removal effects were attributed to strong electrostatic interactions between reactive dyes and the grafted NH{sub 2} groups.

  3. Relationship between NH sub 4 sup + assimilation rate and in vivo phosphoenolpyruvate carboxylase activity

    Energy Technology Data Exchange (ETDEWEB)

    Vanlerberghe, G.C.; Schuller, K.A.; Smith, R.G.; Feil, R.; Plaxton, W.C.; Turpin, D.H. (Queen' s Univ., Kingston, Ontario (Canada))


    The rate of NH{sub 4}{sup +} assimilation by N-limited Selenastrum minutum (Naeg.) Collins cells in the dark was set as an independent variable and the relationship between NH{sub 4}{sup +} assimilation rate and in vivo activity of phosphoenolpyruvate carboxylase (PEPC) was determined. In vivo activity of PEPC was measured by following the incorporation of H{sup 14}CO{sub 3}{sup {minus}} into acid stable products. A linear relationship of 0.3 moles C fixed via PEPC per mole N assimilated was observed. This value agrees extremely well with the PEPC requirement for the synthesis of the amino acids found in total cellular protein. Determinations of metabolite levels in vivo at different rates of N assimilation indicated that the known metabolite effectors of S. minutum PEPC in vitro (KA Schuller, WC Plaxton, DH Turpin, (1990) Plant Physiol 93: 1303-1311) are important regulators of this enzyme during N assimilation. As PEPC activity increased in response to increasing rates of N assimilation, there was a corresponding decline in the level of PEPC inhibitors (2-oxoglutarate, malate), an increase in the level of PEPC activators (glutamine, dihydroxyacetone phosphate), and an increase in the Gln/Glu ratio. Treatment of N-limited cells with azaserine caused an increase in the Gln/Glu ratio resulting in increased PEPC activity in the absence of N assimilation. We suggest glutamate and glutamine play a key role in regulating the anaplerotic function of PEPC in this C{sub 3} organism.

  4. 磷石膏制取硫酸铵及其溶析结晶%(NH4)2SO4 production via reaction of (NH4)2CO3 and phosphogypsum

    Institute of Scientific and Technical Information of China (English)

    何东升; 张泽强; 张汉泉; 池汝安


    The production of (NH4)2SO4 from phosphogypsum and (NH4)2CO3 has been investigated.The factors affecting the conversion of phosphogypsum to (NH4)2SO4, such as (NH4)2CO3 to phosphogypsum ratio, reaction temperature, reaction time, stripping speed and liquid to solid ratio were studied.The optimum reaction conditions obtained at (NH4)2CO3 to phosphogypsum ratio 1.15,50 ℃, reaction time 120 min, stripping speed 150 r/min and liquid to solid ration 5∶ 1.The maximum conversion of phosphogypsum to (NH4)2SO4 obtained under these conditions was 98.68%.A new crystallization method of (NH4)2SO4 was proposed, and the main factors affecting crystallization rate such as crystallization temperature and concentration of sulfate ion have been investigated.Results indicated that temperature and concentration of sulfate ion have obvious effects on crystallization rate of (NH4)2SO4.Suitable temperature was 25 ℃, and the higher the concentration of sulfate ion, the higher the crystallization rate of (NH4)2 SO4.%以磷石膏为原料,利用其与碳酸铵的反应,制备出硫酸铵,并研究了硫酸铵溶液的结晶方法.考查了物料比、反应温度、反应时间、搅拌速度和液固比等因素对磷石膏中硫酸钙转化率的影响.在物料比n(CO2-3)/n(SO2-4)为1.15,50 ℃,120 min,搅拌器转速100 r/min,液固比为51 mL/g时,磷石膏中硫酸钙转化率可达98.68%.以无水乙醇为溶析剂,从硫酸铵溶液中结晶出硫酸铵,结果表明,结晶温度和硫酸根离子浓度对结晶率影响显著,适宜的结晶温度为25 ℃,硫酸根浓度越高,结晶率越高.

  5. NH125 reduces the level of CPEB3, an RNA binding protein, to promote synaptic GluA2 expression. (United States)

    Bender, Crhistian L; Yang, Qian; Sun, Lu; Liu, Siqiong June


    Neuronal activity can alter the phosphorylation state of eukaryotic elongation factor 2 (eEF2) and thereby regulates protein synthesis. This is thought to be the underlying mechanism for a form of synaptic plasticity that involves changes in the expression of synaptic AMPA type glutamate receptors. Phosphorylation of eEF2 by Ca/calmodulin-dependent eEF2 kinase reduces the activity of eEF2, and this is prevented by a commonly used eEF2 kinase inhibitor, NH125. Here we show that 10 μM NH125 increased the expression of synaptic GluA2-containing receptors in mouse cerebellar stellate cells and this was prevented by a protein synthesis inhibitor. However NH125 at 10 μM also reduced the level of CPEB3, a protein that is known to bind to GluA2 mRNA and suppress GluA2 (also known as GluR2) synthesis. In contrast, a low concentration of NH125 lowered the peEF2 level, but did not alter CPEB3 expression and also failed to increase synaptic GluA2 receptors. A selective eEF2 kinase inhibitor, A-484954, decreased the level of peEF2, without changing the expression of CPEB3. This suggests that reducing peEF2 does not lead to a decrease in CPEB3 levels and is not sufficient to increase GluA2 synthesis. Thus NH125 at 10 μM reduced the level of CPEB3, and promoted GluA2 translation via a mechanism independent of inhibition of eEF2 kinase. Therefore NH125 does not always alter protein synthesis via selective inhibition of eEF2 kinase and the effects of NH125 on translation of mRNAs should be interpreted with caution.

  6. Effects of acute NH3 air pollution on N-sensitive and N-tolerant lichen species. (United States)

    Paoli, Luca; Maslaňáková, Ivana; Grassi, Alice; Bačkor, Martin; Loppi, Stefano


    Lichens are sensitive to the presence of ammonia (NH3) in the environment. However, in order to use them as reliable indicators in biomonitoring studies, it is necessary to establish unequivocally the occurrence of certain symptoms following the exposure to NH3 in the environment. In this paper, we simulated an episode of acute air pollution due to the release of NH3. The biological effects of acute air pollution by atmospheric NH3 have been investigated using N-sensitive (Flavoparmelia caperata) and N-tolerant (Xanthoria parietina) species. Lichen samples were exposed to ecologically relevant NH3 concentrations for 8 weeks, simulating three areas of impact: a control area (2 μg/m(3)), an area of intermediate impact (2-35 μg/m(3)) and an area of high impact (10-315 μg/m(3)), with a peak of pollution reached between the fourth and fifth week. Ammonia affected both the photobiont and the mycobiont in F. caperata, while in X. parietina only the photosynthetic performance of the photobiont was altered after exposure to the highest concentration. In the photobiont of F. caperata we recorded chlorophyll degradation as indicated by OD435/415 ratio, decrease of the photosynthetic performance (as reflected by the maximum quantum yield of primary photochemistry FV/FM and the performance index PIABS); in the mycobiont, ergosterol reduction, membrane lipid peroxidation (as reflected by the increase of thiobarbituric acid reactive substances), alteration (decrease) of the secondary metabolite usnic acid. No effects were detected on caperatic acid and dehydrogenase activity. In X. parietina, the only signal determined by NH3 was the alteration of FV/FM and the performance index PIABS. The results suggest that physiological parameters in N-sensitive lichens well reflect the effects of NH3 exposure and can be applied as early indicators in monitoring studies.

  7. Response to nitrate/ammonium nutrition of tomato (Solanum lycopersicum L.) plants overexpressing a prokaryotic NH4(+)-dependent asparagine synthetase. (United States)

    Martínez-Andújar, Cristina; Ghanem, Michel Edmond; Albacete, Alfonso; Pérez-Alfocea, Francisco


    Nitrogen availability is an important limiting factor for plant growth. Although NH4(+) assimilation is energetically more favorable than NO3(-), it is usually toxic for plants. In order to study if an improved ammonium assimilatory metabolism could increase the plant tolerance to ammonium nutrition, tomato (Solanum lycopersicum L. cv P-73) plants were transformed with an NH4(+)-dependent asparagine synthetase (AS-A) gene from Escherichia coli (asnA) under the control of a PCpea promoter (pea isolated constitutive promotor). Homozygous (Hom), azygous (Az) asnA and wild type (WT) plants were grown hydroponically for 6 weeks with normal Hoagland nutrition (NO3(-)/NH4(+)=6/0.5) and high ammonium nutrition (NO3(-)/NH4(+)=3.5/3). Under Hoagland's conditions, Hom plants produced 40-50% less biomass than WT and Az plants. However, under NO3(-)/NH4(+)=3.5/3 the biomass of Hom was not affected while it was reduced by 40-70% in WT and Az plants compared to Hoagland, respectively. The Hom plants accumulated 1.5-4 times more asparagine, glycine, serine and soluble proteins and registered higher glutamine synthetase (GS) and glutamate synthase (GOGAT) activities in the light-adapted leaves than the other genotypes, but had similar NH4(+) and NO3(-) levels in all conditions. In the dark-adapted leaves, a protein catabolism occurred in the Hom plants with a concomitant 25-40% increase in organic acid concentration, while asparagine accumulation registered the highest values. The aforementioned processes might be responsible for a positive energetic balance as regards the futile cycle of the transgenic protein synthesis and catabolism. This explains growth penalty under standard nutrition and growth stability under NO3(-)/NH4(+)=3.5/3, respectively. Copyright © 2013 Elsevier GmbH. All rights reserved.

  8. Latitudinal variation of upper tropospheric NH3 on Saturn derived from Cassini/CIRS far-infrared measurements (United States)

    Hurley, J.; Fletcher, L. N.; Irwin, P. G. J.; Calcutt, S. B.; Sinclair, J. A.; Merlet, C.


    Ammonia (NH3) has been detected both on Saturn and Jupiter, and although its concentration and distribution has been well-studied on Jupiter, it has proven more difficult to do so on Saturn due to higher sensitivity requirements resulting from Saturn's lower atmospheric temperatures and the dominance of Saturn's phosphine which masks the ammonia signal. Using far-infrared measurements of Saturn taken by Cassini/CIRS between February 2005 and December 2010, the latitudinal variations of upper tropospheric ammonia on Saturn are studied. Sensitivity to NH3 in the far-infrared is explored to provide estimates of temperature, para-H2 and PH3, from 2.5 cm-1 spectral resolution measurements alone, 0.5 cm-1 spectral-resolution measurements alone, and 0.5 cm-1 measurements degraded to 2.5 cm-1 spectral resolution. The estimates of NH3 from these three different datasets largely agree, although there are notable differences using the high emission angle 0.5 cm-1 data, which are asserted to result from a reduction in sensitivity at higher emission angles. For low emission angles, the 0.5 cm-1-retrieved values of NH3 can be used to reproduce the 2.5 cm-1 spectra with similar efficacy as those derived directly from the 2.5 cm-1 resolution data itself, and vice versa. Using low emission angle data, NH3 is observed to have broad peak abundances at ±25° latitude, attributed to result from condensation and/or photolytic processes. Lack of data coverage at equatorial latitudes precludes analysis of NH3 abundance at less than about 10° latitude. Noise levels are not sufficient to distinguish fine zonal features, although it seems that NH3 cannot trace the zonal belt/zone structure in the upper troposphere of Saturn.

  9. Atmospheric gas phase chemistry of CH2═NH and HNC. A first-principles approach. (United States)

    Bunkan, Arne Joakim C; Tang, Yizhen; Sellevåg, Stig R; Nielsen, Claus J


    Quantum chemical methods were used to investigate the OH initiated atmospheric degradation of methanimine, CH2═NH, the major primary product in the atmospheric photo-oxidation of methylamine, CH3NH2. Energies of stationary points on potential energy surfaces of reaction were calculated using multireference perturbation theory and coupled cluster theory. The results show that hydrogen abstraction dominates over the addition route in the CH2═NH + OH reaction, and that the major primary product is HCN, while HNC and CHONH2 are minor primary products. HNC is found to react with OH exclusively via addition to the carbon atom followed by O-H scission leading to HNCO; N2O is not a product in the atmospheric photo-oxidation of HNC. Additional G4 calculations of the CH2═NH + O3 reaction show that this is too slow to be of importance at atmospheric conditions. Rate coefficients for the CH2═NH + OH and HNC + OH reactions were calculated as a function of temperature and pressure using a master equation model based on the coupled cluster theory results. The rate coefficients for OH reaction with CH2═NH and HNC at 1000 mbar and room temperature are calculated to be 3.0 × 10(-12) and 1.3 × 10(-11) cm(3) molecule(-1) s(-1), respectively. The atmospheric fate of CH2═NH is discussed and a gas phase photo-oxidation mechanism is presented.

  10. Study on Thermodynamics of K +-NH4+ Ion Exchange on Clinoptilolite%斜发沸石K+-NH+4离子交换热力学特性的研究

    Institute of Scientific and Technical Information of China (English)

    袁俊生; 刘彬; 郑素荣



  11. NH3-NaSCN吸收-压缩式热泵热力学性能研究%Thermodynamic Investigation on NH3 -NaSCN Absorption -compression Heat Pumps

    Institute of Scientific and Technical Information of China (English)



    Absorption - compression heat pumps were well accepted for industrial waste heat recovery. An investigation on NH3 - NaSCN absorption - compression heat pumps was carried out based on the first and second laws of thermodynamics and the effects of the heating temperature, heat source temperature and compression ratio on the performance were obtained, which provided a theoretical base for the optimization of NH3 -NaSCN absorption -compression heat pumps.%吸收-压缩式热泵在工业余热回收利用中有着非常广泛的应用前景。文章基于热力学第一和第二定律对以NH3-NaSCN为工质的吸收一压缩式热泵进行了热力计算和理论分析,得到了NH3-NaSCN吸收一压缩式热泵的热力学性能随供热温度、热源温度及压缩比的变化规律。本文的工作为优化设计NH3-NaSCN吸收-压缩式热泵提供了理论依据。


    Institute of Scientific and Technical Information of China (English)

    朱磊; 胡维军


    We conduct the structural optimization and frequency calculation for one added electron cluster [ (NH3)2(H2O)4] - by the theory method of DFT/BLYP and the basis group with the dispersion function. The binding energy,vibration spectrum and dipole moment are calculated, also the binding fashion and the distribution area of electron are analysed. For the sake of contrast,the neutral cluster (NH3)2(H2O)4 by the same method is calculated, and then the relation and difference between negative and neutral clusters are investigated.%采用DFT/BLYP理论方法和添加额外弥散函数的基组6-31(3+)(1+)G**对包含一个额外电子的[(NH3)2(H2O)4]-团簇进行了结构优化和频率分析.计算了[(NH3)2(H2O)4]-的结合能,振动谱和偶极矩,对电子的束缚方式和电子分布区域也进行了分析.为了比较,还用相同方法对中性团簇(NH3)2(H2O)4进行了计算,进而研究了负电与中性团簇的联系与区别.

  13. Copper(II) and zinc(II) complexes of the peptides Ac-HisValHis-NH2 and Ac-HisValGlyAsp-NH2 related to the active site of the enzyme CuZnSOD. (United States)

    Bóka, Beáta; Myari, Alexandra; Sóvágó, Imre; Hadjiliadis, Nick


    Copper(II) and zinc(II) complexes of the peptides Ac-HisValHis-NH2 and Ac-HisValGlyAsp-NH2 related to the active site of the enzyme CuZnSOD were studied by potentiometric and spectroscopic (UV-Vis, CD and EPR) techniques. The results reveal that both ligands have effective metal binding sites, but the tripeptide is a much stronger complexing agent than the tetrapeptide. The formation of a macrochelate via the coordination of the imidazolyl residues is suggested in the copper(II)-Ac-HisValHis-NH2 system in the acidic pH range, while a 4N complex predominates at physiological pH. The interaction of Ac-HisValHis-NH2 with zinc(II) results in the formation of a precipitate indicating polynuclear complex formation. Both copper(II)-Ac-HisValHis-NH2 and copper(II)-HisValHis systems exhibit catalytic activity toward the dismutation of superoxide anion at physiological pH, but the saturated coordination sphere of the metal ions in both systems results in low reactivity as compared to the native enzyme.

  14. 铜离子络合法测定HBP-NH2溶液含量及其应用%Determination of concentration of HBP-NH2 Solution by complexometric titration with Cu2+

    Institute of Scientific and Technical Information of China (English)

    张峰; 陈宇岳; 张德锁



  15. Growth kinetics and micromorphology of NH{sub 4}Cl:Mn{sup 2+} crystals formed in the NH{sub 4}Cl-MnCl{sub 2}-H{sub 2}O-CONH{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Pyankova, L. A., E-mail:; Punin, Yu. O.; Bocharov, S. N.; Shtukenberg, A. G. [Petersburg State University (Russian Federation)


    The growth kinetics and elementary growth processes on the surface of NH{sub 4}Cl:Mn{sup 2+} heterogeneous crystals formed in the NH{sub 4}Cl-MnCl{sub 2}-H{sub 2}O-CONH{sub 3} system are experimentally studied. It is found that a change in the composition of complexes in an NH{sub 4}Cl crystal from Mn(NH{sub 4}){sub 2}Cl{sub 4} {center_dot} 2H{sub 2}O to MnCl{sub 2} {center_dot} 2CONH{sub 3} leads to the occurrence of a local maximum in the kinetic curve and a change in the shape of dislocation growth centers from flat to conical. The growth kinetics of {l_brace}100{r_brace} faces of heterogeneous NH{sub 4}Cl:Mn{sup 2+} crystals is described within the Bliznakov model using the Fowler-Guggenheim adsorption isotherm, which takes into account the lateral interaction of adsorbed particles.

  16. ANIMALS - INDIVIDUAL - COUNTS, Flight direction, SPECIES IDENTIFICATION, ANIMALS - GROUP - BEHAVIOR and WIND SPEED visual observation data collected in the North Pacific Ocean on the NEW HORIZON cruises NH0005 and NH0007 as part of the NEP project from 2000-05-30 to 2000-08-12 (NODC Accession 0113338) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113338 includes meteorological, visual observation and biological data collected aboard the NEW HORIZON during cruises NH0005 and NH0007 in the North...

  17. ANIMALS - INDIVIDUAL - COUNTS, cetacean and SPECIES IDENTIFICATION marine mammal observation and visual observation data collected in the North Pacific Ocean on the NEW HORIZON cruises NH0005 and NH0007 as part of the NEP project from 2000-05-31 to 2000-08-12 (NODC Accession 0113948) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113948 includes marine mammal observation, visual observation and biological data collected aboard the NEW HORIZON during cruises NH0005 and NH0007...

  18. WIND DIRECTION and WIND SPEED underway - surface data collected in the North Pacific Ocean on the NEW HORIZON cruises NH0005 and NH0007 as part of the NEP project from 2000-05-30 to 2000-08-12 (NODC Accession 0113337) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113337 includes underway - surface and meteorological data collected aboard the NEW HORIZON during cruises NH0005 and NH0007 in the North Pacific...

  19. Thickness distributions and evolution of growth mechanisms of NH4-illite from the fossil hydrothermal system of Harghita Bai, Eastern Carpathians, Romania (United States)

    Bobos, Iuliu; Eberl, D.D.


    The crystal growth of NH4-illite (NH4-I) from the hydrothermal system of Harghita Bãi (Eastern Carpathians) was deduced from the shapes of crystal thickness distributions (CTDs). The 4-illite-smectite (I-S) interstratified structures (R1, R2, and R3-type ordering) with a variable smectite-layer content. The NH4-I-S (40–5% S) structures were identified underground in a hydrothermal breccia structure, whereas the K-I/NH4-I mixtures were found at the deepest level sampled (−110 m). The percentage of smectite interlayers generally decreases with increasing depth in the deposit. This decrease in smectite content is related to the increase in degree of fracturing in the breccia structure and corresponds to a general increase in mean illite crystal thickness. In order to determine the thickness distributions of NH4-I crystals (fundamental illite particles) which make up the NH4-I-S interstratified structures and the NH4,-I/K-I mixtures, 27 samples were saturated with Li+ and aqueous solutions of PVP-10 to remove swelling and then were analyzed by X-ray diffraction. The profiles for the mean crystallite thickness (Tmean) and crystallite thickness distribution (CTD) of NH4-I crystallites were determined by the Bertaut-Warren-Averbach method using the MudMaster computer code. The Tmean of NH4-I from NH4-I-S samples ranges from 3.4 to 7.8 nm. The Tmean measured for the NH4-I/K-I mixture phase ranges from 7.8 nm to 11.7 nm (NH4-I) and from 12.1 to 24.7 nm (K-I). The CTD shapes of NH4-I fundamental particles are asymptotic and lognormal, whereas illites from NH4-I/K-I mixtures have bimodal shapes related to the presence of two lognormal-like CTDs corresponding to NH4-I and K-I. The crystal-growth mechanism for NH4-I samples was simulated using the Galoper code. Reaction pathways for NH4-I crystal nucleation and growth could be determined for each sample by plotting their CTD parameters on an α–β2 diagram constructed using Galoper. This analysis shows that NH4-I

  20. Radio-Frequency-Based NH3-Selective Catalytic Reduction Catalyst Control: Studies on Temperature Dependency and Humidity Influences

    Directory of Open Access Journals (Sweden)

    Markus Dietrich


    Full Text Available The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF catalyst state determination offers the only approach for directly measuring the NH3 loading on selective catalytic reduction (SCR catalysts and the state of other catalysts and filter systems. Recently, the ability of this technique to directly control the urea dosing on a current NH3 storing zeolite catalyst has been demonstrated on an engine dynamometer for the first time and this paper continues that work. Therefore, a well-known serial-type and zeolite-based SCR catalyst (Cu-SSZ-13 was investigated under deliberately chosen high space velocities. At first, the full functionality of the RF system with Cu-SSZ-13 as sample was tested successfully. By direct RF-based NH3 storage control, the influence of the storage degree on the catalyst performance, i.e., on NOx conversion and NH3 slip, was investigated in a temperature range between 250 and 400 °C. For each operation point, an ideal and a critical NH3 storage degree was found and analyzed in the whole temperature range. Based on the data of all experimental runs, temperature dependent calibration functions were developed as a basis for upcoming tests under transient conditions. Additionally, the influence of exhaust humidity was observed with special focus on cold start water and its effects to the RF signals.

  1. Crystal structures and 77Se NMR spectra of molybdenum(IV) areneselenolates having intramolecular NH...Se hydrogen bonds. (United States)

    Okamura, Taka-Aki; Taniuchi, Kaku; Lee, Keonil; Yamamoto, Hitoshi; Ueyama, Norikazu; Nakamura, Akira


    Salts of the monooxomolybdenum(IV,V) areneselenolates having intramolecular NH...Se hydrogen bonds, [Mo(IV)O(Se-2-RCONHC6H4)4]2- (R = t-Bu, CH3, CF3) and [Mo(V)O(Se-2-t-BuCONHC6H4)4]-, were synthesized and characterized by 1H nuclear magnetic resonance (NMR), 77Se NMR, electron spin resonance (ESR), UV-visible spectra, X-ray analysis, and electrochemical measurements. 77Se-1H correlated spectroscopy (COSY) indicated a significant correlation between amide 1H and selenolate 77Se atoms through an NH...Se hydrogen bond with 1J(77Se-1H) = 5.4 Hz coupling. The hydrogen bonds contribute to the positive shift in the Mo(V)/Mo(IV) redox potential. In the crystal structure of (PPh4)2[Mo(IV)O(Se-2-CH3CONHC6H4)4], an NH...O=Mo hydrogen bond was found. Ab inito calculations support the presence of intramolecular NH...O=Mo and NH...Se hydrogen bonds.

  2. A novel humidity sensor based on NH2-MIL-125(Ti) metal organic framework with high responsiveness (United States)

    Zhang, Ying; Chen, Yu; Zhang, Yupeng; Cong, Huahua; Fu, Bo; Wen, Shanpeng; Ruan, Shengping


    A novel porous nanosized humidity-sensing material of amine-functionalized titanium metal organic framework (MOF), NH2-MIL-125(Ti), was investigated. NH2-MIL-125(Ti) nanoparticles with high phase purity and good physicochemical property were synthesized by a simple hydrothermal method. The nanosized MOF was characterized by X-ray diffraction and scanning electron microscope. The average size of the MOF nanoparticles is around 300 nm. Then NH2-MIL-125(Ti) humidity sensor was fabricated by coating the nanosized materials on interdigitated electrodes. The humidity sensor based on NH2-MIL-125(Ti) shows good linearity of RH (11-95 % RH), as well as fast response and recovery time. The RH detecting range is from 11 to 95 % RH at 100 Hz. The response and recovery time are about 45 and 50 s, respectively. Moreover, the sensing mechanism was discussed by complex impedance analysis in detail. These results indicate the potential application of NH2-MIL-125(Ti) in humidity sensors.

  3. Novel Ce-W-Sb mixed oxide catalyst for selective catalytic reduction of NOx with NH3 (United States)

    Liu, Jun; Li, Guo-qiang; Zhang, Yong-fa; Liu, Xiao-qing; Wang, Ying; Li, Yuan


    A novel Ce3W2SbOx catalyst prepared by the co-precipitation method have been investigated for the selective catalysis reduction (SCR) of NOx with NH3. It was found that the Ce-W-Sb oxide catalyst exhibited an excellent conversion ratio of NOx and a high tolerance to H2O and SO2 in a wide operation temperature window. The catalysts were characterized by N2-adsorption, XRD, Raman, H2-TPR, NH3-TPD, XPS and DRIFTS. The results suggest that the strong interaction between Sb, W and Ce species not only enhances the redox property of the catalyst but also increases the surface acidity, thus promoting the adsorption and activation of NH3 species, which is favorable for high NH3-SCR performance. Based on in situ DRIFTS results, it was concluded that the Langmuir-Hinshelwood (L-H) mechanism existed at the temperature of below 300 °C, while at above 300 °C the Eley-Rideal (E-R) mechanism dominate the NH3-SCR reaction over the Ce3W2SbOx catalyst. Overall, these findings indicate that Ce3W2SbOx is promising for industrial applications.

  4. Reversible flexible structural changes in multidimensional MOFs by guest molecules (I2, NH3) and thermal stimulation (United States)

    Chen, Yang; Li, Libo; Yang, Jiangfeng; Wang, Shuang; Li, Jinping


    Three metal-organic frameworks (MOFs), [Cu(INA)2], [Cu(INA)2I2] and [Cu(INA)2(H2O)2(NH3)2], were synthesized with 3D, 2D, and 0D structures, respectively. Reversible flexible structural changes of these MOFs were reported. Through high temperature (60-100 °C) stimulation of I2 or ambient temperature stimulation of NH3, [Cu(INA)2] (3D) converted to [Cu(INA)2I2] (2D) and [Cu(INA)2(H2O)2(NH3)2] (0D); as the temperature increased to 150 °C, the MOFs changed back to their original form. In this way, this 3D MOF has potential application in the capture of I2 and NH3 from polluted water and air. XRD, TGA, SEM, NH3-TPD, and the measurement of gas adsorption were used to describe the changes in processes regarding the structure, morphology, and properties.

  5. ZnCl{sub 2}- and NH{sub 4}Cl-hydroponics gel electrolytes for zinc-carbon batteries

    Energy Technology Data Exchange (ETDEWEB)

    Khalid, N.H.; Ismail, Y.M. Baba; Mohamad, A.A. [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)


    Absorbency testing is used to determine the percentage of ZnCl{sub 2} or NH{sub 4}Cl solution absorbed by a hydroponics gel (HPG). It is found that the absorbency of ZnCl{sub 2} or NH{sub 4}Cl solution decreases with increasing solution concentration. The conductivity of ZnCl{sub 2}- and NH{sub 4}Cl-HPG electrolytes is dependent on the solution concentration. A mixture of salt solution with HPG yields excellent gel polymer electrolytes with conductivities of 0.026 and 0.104 S cm{sup -1} at 3 M ZnCl{sub 2} and 7 M NH{sub 4}Cl, respectively. These gel electrolytes are then used to produce zinc-carbon cells. The fabricated cells give capacities of 8.8 and 10.0 mAh, have an internal resistance of 25.4 and 19.8 {omega}, a maximum power density of 12.7 and 12.2 mW cm{sup -2}, and a short-circuit current density of 29.1 and 33.9 mA cm{sup -2} for ZnCl{sub 2}- and NH{sub 4}Cl-HPG electrolytes, respectively. (author)

  6. ZnCl 2- and NH 4Cl-hydroponics gel electrolytes for zinc-carbon batteries (United States)

    Khalid, N. H.; Ismail, Y. M. Baba; Mohamad, A. A.

    Absorbency testing is used to determine the percentage of ZnCl 2 or NH 4Cl solution absorbed by a hydroponics gel (HPG). It is found that the absorbency of ZnCl 2 or NH 4Cl solution decreases with increasing solution concentration. The conductivity of ZnCl 2- and NH 4Cl-HPG electrolytes is dependent on the solution concentration. A mixture of salt solution with HPG yields excellent gel polymer electrolytes with conductivities of 0.026 and 0.104 S cm -1 at 3 M ZnCl 2 and 7 M NH 4Cl, respectively. These gel electrolytes are then used to produce zinc-carbon cells. The fabricated cells give capacities of 8.8 and 10.0 mAh, have an internal resistance of 25.4 and 19.8 Ω, a maximum power density of 12.7 and 12.2 mW cm -2, and a short-circuit current density of 29.1 and 33.9 mA cm -2 for ZnCl 2- and NH 4Cl-HPG electrolytes, respectively.

  7. Detection of NH{sub 3} by quartz crystal microbalance coated with TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, V; Spassov, L; Gadjanova, V [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Donkov, N; Petkov, P [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chausee, 1784 Sofia (Bulgaria)], E-mail:


    A quartz resonator with a thin TiO{sub 2} film is investigated in view of possible applications as a sensor for detecting the presence of ammonia in the ambient. A study of the sorption properties of thin TiO{sub 2} films to NH{sub 3} vapors is also presented. The films are deposited using electron beam evaporation. In order to determine the sorption ability of TiO{sub 2} to NH{sub 3}, a quartz crystal microbalance (QCM) with a thin TiO{sub 2} film is used, the latter serving as a receptor for the NH{sub 3} gas. The AT-cut 16-MHz quartz resonator allows conversion of the additional mass load that occurs as a result of sorption into a frequency shift. The experiments are carried out by measuring the QCM resonant frequency shift due to the absorption of vapors from an aqueous solution of NH{sub 3} with different concentration ranging from 100 to 1000 ppm. The experimental results obtained indicate that the variation of the resonant frequency is a function of the ammonia concentration. This demonstrates that a QCM covered with a thin TiO{sub 2} layer is sensitive to ammonia vapors at room temperature and is capable of detecting NH{sub 3} concentrations in the range investigated (100-1000 ppm)

  8. Study on PEG-(NH4)2SO4 Aqueous Two-Phase System and Distribution Behavior of Drugs

    Institute of Scientific and Technical Information of China (English)

    LI, Lei(李蕾); HE, Chi-Yang(何池洋); LI, She-Hong(李社红); LIU, Feng(刘锋); SU, Shun(苏顺); KONG, Xiang-Xu(孔祥旭); LI, Na(李娜); LI, Ke-An(李克安)


    The distribution behavior of chlorpromazine hydrochloride (CPZ), procaine hydrochloride (PCN) and procaine amide hydrochloride (PCNA) in polyethylene glycol (PEG800 or PEG1500)-(NH4)2SO4 aqueous two-phase systems has been investigated. The result shows that the PEG-(NH4)2SO4 aqueous two-phase system has potential extraction capability in small molecular drug separation. In PEG800-(NH4)2SO4 system, the extraction efficiencies (E)of CPZ, PCN and PCNA amount to 92.8%, 74.5% and 74.4%, respectively, with the distribution coefficients (KD)being 25.7, 5.9 and 5.8, correspondingly. In PEG1500-(NH4)2SO4 system, the extraction efficiencies (E) of CPZ,PCN and PCNA are 93.7%, 71.3% and 63.2%, respectively, with distribution coefficients (KD) of 39.6, 6.6 and 5.0,correspondingly. Based on the study on ultraviolet and fluorescence spectra and also distribution behavior of the drugs in PEG-(NH4)2SO4 aqueous two-phase system, extraction mechanism was further proposed that both hydrogen bond and hydrophobic interaction are involved in extraction.

  9. Radio-Frequency-Based NH3-Selective Catalytic Reduction Catalyst Control: Studies on Temperature Dependency and Humidity Influences (United States)

    Dietrich, Markus; Hagen, Gunter; Reitmeier, Willibald; Burger, Katharina; Hien, Markus; Grass, Philippe; Kubinski, David; Visser, Jaco; Moos, Ralf


    The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF) catalyst state determination offers the only approach for directly measuring the NH3 loading on selective catalytic reduction (SCR) catalysts and the state of other catalysts and filter systems. Recently, the ability of this technique to directly control the urea dosing on a current NH3 storing zeolite catalyst has been demonstrated on an engine dynamometer for the first time and this paper continues that work. Therefore, a well-known serial-type and zeolite-based SCR catalyst (Cu-SSZ-13) was investigated under deliberately chosen high space velocities. At first, the full functionality of the RF system with Cu-SSZ-13 as sample was tested successfully. By direct RF-based NH3 storage control, the influence of the storage degree on the catalyst performance, i.e., on NOx conversion and NH3 slip, was investigated in a temperature range between 250 and 400 °C. For each operation point, an ideal and a critical NH3 storage degree was found and analyzed in the whole temperature range. Based on the data of all experimental runs, temperature dependent calibration functions were developed as a basis for upcoming tests under transient conditions. Additionally, the influence of exhaust humidity was observed with special focus on cold start water and its effects to the RF signals. PMID:28704929

  10. Investigation on interfacial and electrical properties of Ge MOS capacitor with different NH3-plasma treatment procedure (United States)

    Liu, Xiaoyu; Xu, Jingping; Liu, Lu; Cheng, Zhixiang; Huang, Yong; Gong, Jingkang


    The effects of different NH3-plasma treatment procedures on interfacial and electrical properties of Ge MOS capacitors with stacked gate dielectric of HfTiON/TaON were investigated. The NH3-plasma treatment was performed at different steps during fabrication of the stacked gate dielectric, i.e. before or after interlayer (TaON) deposition, or after deposition of high-k dielectric (HfTiON). It was found that the excellent interface quality with an interface-state density of 4.79 × 1011 eV-1 cm-2 and low gate leakage current (3.43 × 10-5 A/cm2 at {V}{{g}}=1 {{V}}) could be achieved for the sample with NH3-plasma treatment directly on the Ge surface before TaON deposition. The involved mechanisms are attributed to the fact that the NH3-plasma can directly react with the Ge surface to form more Ge-N bonds, i.e. more GeO x Ny, which effectively blocks the inter-diffusion of elements and suppresses the formation of unstable GeO x interfacial layer, and also passivates oxygen vacancies and dangling bonds near/at the interface due to more N incorporation and decomposed H atoms from the NH3-plasma. Project supported by the National Natural Science Foundation of China (Nos. 61176100, 61274112).

  11. On-road measurement of NH3 and N2O emissions from a Euro V heavy-duty vehicle (United States)

    Suarez-Bertoa, Ricardo; Mendoza-Villafuerte, Pablo; Bonnel, Pierre; Lilova, Velizara; Hill, Leslie; Perujo, Adolfo; Astorga, Covadonga


    The use of selective catalytic reduction systems (SCR) to abate NOx vehicular emissions brings new concerns on the emissions of the byproducts NH3 and N2O. Therefore, NH3 and N2O on-road emissions from a Euro V truck equipped with a SCR were measured in real time using a QCL-IR. Results bring to light possibility to perform this kind of real time measurements for other pollutants besides, hydrocarbons, NOx, CO and CO2. The capability to measure NH3 and N2O in a second-by-second basis will allow applying the currently agreed regulatory emissions evaluation for gaseous compounds. Average N2O emission factors calculated applying the current PEMS-based data analysis to all available windows from the tests ranged from 0.063 g/kWh to 0.139 g/kWh. Average NH3 concentrations ranged from 0.9 ppm to 5.7 ppm. Although calculated average N2O and NH3 emissions were within current limits, NOx emissions were substantially higher than Euro V limits under the studied conditions.

  12. C6H5NH2 effect on the corrosion inhibition of aluminium in 0.5 M HCl (United States)

    Omotosho, Olugbenga Adeshola; Okeniyi, Joshua Olusegun; Loto, Cleophas Akintoye; Popoola, Abimbola Patricia Idowu; Fademi, Ekundayo Oluwademilade Jacob; Oladipupo, Segun Isaac; Alabi, Ayomide Samuel; Ajibola, Omokolade Bamidele; Emelieze, Alex Nwabunor


    In this paper, C6H6NH2 (aniline) effect on the corrosion of aluminium in 0.5 M (i.e. mol/L) HCl medium was studied using gravimetric method by weight loss measurements and electrochemical technique of corrosion potential and potentiodynamic polarization by cyclic voltamery (CV) instrumentation. By these techniques, corrosion rate obtained from aluminium specimens, in 0.5 HCl test-solution having different concentrations of the hydrogen-containing C6H6NH2 chemical, were requisitely analysed. Results showed that the potentiodynamic corrosion rate excellently correlated (R = 98.94%, Nash-Sutcliffe efficiency = 97.89% and ANOVA p-value = 0.0314) with function of the gravimetric corrosion rate and C6H5NH2 concentration. Both experimental and correlated prediction models identified 0.043 mol/L C6H5NH2 with optimal inhibition efficiency performance η = 84.11% by the experimental or η = 81.15% by the predicted models. Fittings of experimental and correlated data showed the data models followed the Langmuir adsorption isotherm from which favourable adsorption and prevalent physisorption were indicated as the C6H5NH2 corrosion-protection on aluminium metal in the 0.5 M HCl medium.

  13. Investigating the two inequivalent NH2(CH3)2 ions in [NH2(CH3)2]2CuCl4 using magic angle spinning nuclear magnetic resonance (United States)

    Lim, Ae Ran; Paik, Younkee


    The structural change near the phase transition temperatures of [NH2(CH3)2]2CuCl4 is discussed in terms of the chemical shifts and the spin-lattice relaxation times T1ρ in the rotating frame for 1H MAS NMR and 13C CP/MAS NMR. The 1H T1ρ undergoes molecular motion near the phase-transition temperature (TC2 = 253 K). In addition, the two inequivalent [NH2(CH3)2] (1) and [NH2(CH3)2] (2) sites were distinguishable by the 13C chemical shift. And, the most significant change was observed at TC2 for the 13C CP/MAS NMR spectrum; this temperature corresponds to a ferroelastic phase transition with different orientations.

  14. Dyeing behaviour on oxidized linen grafted with HBP-NH2%HBP-NH2接枝氧化亚麻织物无盐染色性能

    Institute of Scientific and Technical Information of China (English)

    赵兵; 张峰; 林红; 陈宇岳



  15. Electroless copper plating of PET fabric activated with HBP-NH2/Ag+%HBP-NH2/Ag+活化涤纶织物的化学镀铜工艺

    Institute of Scientific and Technical Information of China (English)

    檀国登; 沈勇; 张惠芳; 颜峰; 俞菁




    Directory of Open Access Journals (Sweden)

    Siti Norma Nasution


    Full Text Available This study explores the problems of women , patriarchal culture and the fight for gender equality as exposed in Nh. Dini’s novels. There are still many women who are trapped in domestic sector and loose their rights to manage their own lives with their own way. There have been many women who are successful working in public sector, but the number are still very small compared to the number of men who are successful. This study tends to expose the problems of women to reach gender equality for women. This study is importantly conducted because Nh. Dini’s literary works reveal the problems of women related to patriarchal culture which hampers the progress of women. The present study is different with the previous one, because this study explores feminism ideology which is against patriarchal culture and tradition which is still adopted by people as portrayed in five novels of Nh. Dini. The theory of Dinamic Structuralism is used to explain the interconnection of all aspects and components of the novels to get the complete meaning. The theory of Sociology of Literature is used to relate the social problems in the novels to the realities in the real world. The theory of Feminism is used to understand the novels related to women problems, patriarchal culture and gender equality. Text analysis based on the problems of the study revealed that many women are still trapped in domestic sector, still dominated by patriarchal culture. They loose their fundamental rights to manage their own lives and to improve their lives quality to become qualified women. Consenquently the women are so dependent on other people. Analysis about the factors which caused the poverty and misery of women revealed that the main cause of the women problems in the novels is patriarchal culture. The women are not permitted to work in public sector to earn their own lives. Consenquently many women become poor for being jobless. The fight for gender equality that revealed in five

  17. NH3, H2S, and the Radio Brightness Temperature Spectra of the Giant Planets (United States)

    Spilker, Thomas R.


    Recent radio interferometer observations of Neptune enable comparisons of the radio brightness temperature (T(sub B)) spectra of all four giant planets. This comparison reveals evidence for fundamental differences in the compositions of Uranus' and Neptune's upper tropospheres, particularly in their ammonia (NH3) and hydrogen sulfide (H2S) mixing ratios, despite those planets' outward similarities. The tropospheric abundances of these constituents yield information about their deep abundances, and ultimately about the formation of the planets from the presolar nebula (Atreya et al.). Figures 1, 2, 3, and 4 show the T(sub B) spectra of Jupiter, Saturn, Uranus, and Neptune, respectively, from 0.1 to tens of cm wavelength. The data shown are collected from many observers. Data for Jupiter, Saturn, and Uranus are those cataloged by de Pater and Massie (1985), plus the Saturn Very Large Array (VLA) data by Grossman et al. Figure 3, Uranus, shows only data acquired since 1973. Before 1973 Uranus' T(sub B) increased steadily as its pole moved into view, causing significant scatter in those data. Neptune data at greater than 1 cm, all taken at the VLA, are collected from de Pater and Richmond, de Pater et al., and Hofstadter. For a variety of reasons, such as susceptibility to source confusion, single-dish data at those wavelengths are much noisier than the more reliable VLA data and have been ignored. Single-dish data by Griffin and Orton shortward of 0.4 cm are shown, along with the Owens Valley Radio Observatory (interferometer) datum at 0.266 cm by Muhleman and Berge. Spectra of Jupiter, Saturn, and Neptune share certain gross characteristics. In each spectrum, T(sub B) at 1.3 cm is approximately 120-140 K, less than approximately 30 K different from that at 0.1 cm. All three spectra show a break in slope at or near 1.3 cm, with T(sub B) increasing fairly rapidly with wavelength longward of 1.3 cm. Visible and IR spectroscopy show that NH3, whose strong inversion

  18. Analogues of Cis- and Transplatin with a Rich Solution Chemistry: cis-[PtCl2 (NH3 )(1-MeC-N3)] and trans-[PtI2 (NH3 )(1-MeC-N3)]. (United States)

    Siebel, Sabine; Dammann, Claudia; Sanz Miguel, Pablo J; Drewello, Thomas; Kampf, Gunnar; Teubner, Natascha; Bednarski, Patrick J; Freisinger, Eva; Lippert, Bernhard


    Mono(nucleobase) complexes of the general composition cis-[PtCl2 (NH3 )L] with L=1-methylcytosine, 1-MeC (1 a) and L=1-ethyl-5-methylcytosine, as well as trans-[PtX2 (NH3 )(1-MeC)] with X=I (5 a) and X=Br (5 b) have been isolated and were characterized by X-ray crystallography. The Pt coordination occurs through the N3 atom of the cytosine in all cases. The diaqua complexes of compounds 1 a and 5 a, cis-[Pt(H2 O)2 (NH3 )(1-MeC)](2+) and trans-[Pt(H2 O)2 (NH3 )(1-MeC)](2+) , display a rich chemistry in aqueous solution, which is dominated by extensive condensation reactions leading to μ-OH- and μ-(1-MeC(-) -N3,N4)-bridged species and ready oxidation of Pt to mixed-valence state complexes as well as diplatinum(III) compounds, one of which was characterized by X-ray crystallography: h,t-[{Pt(NH3 )2 (OH)(1-MeC(-) -N3,N4)}2 ](NO3 )2 ⋅2 [NH4 ](NO3 )⋅2 H2 O. A combination of (1) H NMR spectroscopy and ESI mass spectrometry was applied to identify some of the various species present in solution and the gas phase, respectively. As it turned out, mass spectrometry did not permit an unambiguous assignment of the structures of +1 cations due to the possibilities of realizing multiple bridging patterns in isomeric species, the occurrence of different tautomers, and uncertainties regarding the Pt oxidation states. Additionally, compound 1 a was found to have selective and moderate antiproliferative activity for a human cervix cancer line (SISO) compared to six other human cancer cell lines.

  19. CS-PVA-NH_4Cl共混固态聚合物电解质膜的制备与性能%Synthesis and Properties of CS-PVA-NH_4Cl Blend Solid Polymer Electrolyte Membranes

    Institute of Scientific and Technical Information of China (English)

    杨丞; 闫康平


    以壳聚糖(CS),聚乙烯醇(PVA)为基体掺杂不同比例NH4Cl进行共混,使用溶液浇铸法制备了CS-PVA-NH4Cl共混固态聚合物电解质膜,溶胀度均在1 000%左右。使用交流阻抗,直流极化,循环伏安对其电导率、离子迁移率及电化学稳定窗口进行测量,使用Zview软件对交流阻抗谱进行拟合。结果表明在40%NH4Cl掺杂时电导率为1.4×,离子迁移率为0.93,电化学稳定窗口为2.0V。%In this paper,CS-PVA-NH4Cl blend solid polymer electrolyte membrane is prepared via solution casting method by using chitosan(CS) and polyvinyl alcohol(PVA) as matrix blended with different amount of NH4Cl,the swelling rates of every sample are all around 1 000%.The conductivity,ion mobility and electrochemical stability of the SPE membranes are investigated by using AC impedance and DC polarization,cyclic voltammetry,and Zview software is used to fit the AC impedance spectroscopy.The results show that with 40% NH4Cl blending,the conductivity was 1.4 × 10-3S·cm-1,the ion mobility was 0.93,the electrochemical stability window is 2.0 V.

  20. Preparation of Adsorbent Based on Modiifcation of Cotton Fibers by HBP-NH2 and Its Property%HBP-NH2改性棉纤维吸附剂的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    孙凤; 臧传峰; 闫腾; 张德锁; 陈宇岳; 林红


    A modified cotton fiber adsorbent was prepared successfully by grafting amino-terminated hyperbranched polymer (HBP-NH2) onto oxidized cotton ifbers. Its technology of preparation was optimized based on the adsorption quantity of Cd2+. The results showed that the modiifed cotton ifbers have the highest adsorption capacity up to Cd2+when 20 g/L HBP-NH2 reacted with oxidized cotton ifbers at 60℃and 11.03 pH value for 2 h. The adsorption quantity of Cd2+could reach 38.94 mg/g.%本研究通过氧化活化棉纤维的方法将端氨基超支化聚合物(HBP-NH2)接枝到棉纤维表面,成功制备了一种HBP-NH2改性棉纤维吸附剂,并以Cd2+的吸附量为依据对吸附剂的制备工艺进行了优化。研究表明HBP-NH2改性棉纤维吸附剂最佳制备工艺为:在60℃下,pH值为11.03的20 g/L HBP-NH2溶液中(浴比1∶50),接枝反应2 h,所制备的改性棉纤维对Cd2+的吸附量最高,可达38.94 mg/g。

  1. 利用氢氧化镁热分解氯化铵制氨气工艺的研究%Research on preparation of NH3 by using thermal decomposition of NH4 Cl and Mg ( OH ) 2

    Institute of Scientific and Technical Information of China (English)

    罗弦; 曾波


    Thermodynamic calculation and analysis were made for the reaction system of preparing NH3 by using thermal decomposition of NH4 Cl and Mg ( OH) 2. Process conditions of the preparation of NH3 were investigated with reaction temperature, amount-of-substance ratio, and reaction time as the variables and with nitrogen content of solid product .chlorine yield,and NH3 yield as evaluation indexes. Results showed the chlorine yield and NH3 yield both could reach more than 90% and the decomposition of Mg( OH)2 and NH4C1 could directly produce NH3 without inletting water steam into the reactor when the reaction temperature was 375 ℃, reaction time was 50 min, and amount -of-substance ratio of Mg ( OH) 2 to NH4C1 was 1:0.75.%对利用氢氧化镁热分解氯化铵制氨气反应体系进行了热力学计算分析,以反应温度、反应物的物质的量比、反应时间为变量,以固体产物中的含氮量、氯收率以及氨气收率等为评价指标,对氢氧化镁热分解氯化铵制氨气的工艺条件进行了研究.实验结果表明,在反应温度为375℃,氢氧化镁与氯化铵的物质的量比为1∶0.75,反应时间为50 min时,氯收率和氨气收率均可达到90%以上,同时氢氧化镁分解氯化铵能够直接生成碱式氯化镁,不需向反应器中通入水蒸气.

  2. First-principles calculation of bulk photovoltaic effect in CH$_3$NH$_3$PbI$_3$ and CH$_3$NH$_3$PbI$_{3-x}$Cl$_{x}$


    Zheng, Fan; Takenaka, Hiroyuki; Wang, Fenggong; Koocher, Nathan Z.; Rappe, Andrew M.


    Hybrid halide perovskites exhibit nearly 20% power conversion efficiency, but the origin of their high efficiency is still unknown. Here, we compute the shift current, a dominant mechanism of bulk photovoltaic (PV) effect for ferroelectric photovoltaics, in CH$_3$NH$_3$PbI$_3$ and CH$_3$NH$_3$PbI$_{3-x}$Cl$_{x}$ from first principles. We find that these materials give approximately three times larger shift current PV response to near-IR and visible light than the prototypical ferroelectric ph...

  3. Calculation of H2O-NH3-CO2 Vapor Liquid Equilibria at High Concentration Conditions%高浓度H2O-NH3-CO2体系汽液平衡计算

    Institute of Scientific and Technical Information of China (English)

    魏顺安; 张红晶


    A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃,pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.

  4. Structure of intermediate phase II of LiNH2 under high pressure. (United States)

    Yamawaki, Hiroshi; Fujihisa, Hiroshi; Gotoh, Yoshito; Nakano, Satoshi


    A new intermediate phase (phase II) was found between phases I and III in LiNH2 in the pressure range of 10 to 13 GPa through the analysis of infrared and powder X-ray diffraction measurements to 25 GPa at room temperature. This result agreed with the prediction of a stable phase between phases I and III through theoretical calculations. Powder X-ray diffraction measurement and DFT calculation showed that this phase has a monoclinic structure with space group C2/c (Z = 8), which is the same structure as that of a slightly tilted crystal lattice of the Fddd structural model. The enthalpy of the C2/c structure was also found to be almost the same as that of the Fddd structure.

  5. Paralytic shellfish poisons produced by the freshwater cyanobacterium Aphanizomenon flos-aquae NH-5. (United States)

    Mahmood, N A; Carmichael, W W


    A single filament clonal isolate of Aphanizomenon flos-aquae was made from a water bloom sample taken at a small pond near Durham, New Hampshire, in 1980. When batch cultured the strain was toxic to mice and had an i.p. LD50 of about 5.0 mg/kg. Using an extraction procedure originally designed for paralytic shellfish poisons and other neurotoxins of freshwater cyanobacteria, a purification method was developed. The procedure involved acidified water/ethanol extraction of the cells followed by ultrafiltration, gel filtration, use of C18 cartridges to remove pigments, ion-exchange and high performance liquid chromatography using u.v. detection at 220 or 240 nm. Thin-layer chromatography and high performance liquid chromatography results indicate that Aphanizomenon flos-aquae NH-5 may produce paralytic shellfish poisons, mainly neo-saxitoxin and saxitoxin. Three labile toxins were also detected which were not similar to any of the known paralytic shellfish poisons.

  6. Crystal structure of NH4[La(SO42(H2O

    Directory of Open Access Journals (Sweden)

    Meriem Benslimane


    Full Text Available The principal building units in the crystal structure of ammonium aquabis(sulfatolanthanate(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 formation of a three-dimensional anionic [La(SO42(H2O]− framework that is stabilized by O—H...O hydrogen-bonding interactions. The disordered ammonium cations are situated in the cavities of this framework and are hydrogen-bonded to six surrounding O atoms.

  7. Theoretical radiative properties between states of the triplet manifold of NH radical. (United States)

    Owono Owono, L C; Ben Abdallah, D; Jaidane, N; Lakhdar, Z Ben


    Ab initio transition dipole moments between states of the triplet manifold of NH radical are determined at the complete active space self-consistent field, followed by the internally contracted multireference singles plus doubles configuration interaction level of theory with a modified aug-cc-pVTZ basis set that accounts for valence-Rydberg interactions. This enables the computation of various radiative characteristics such as Einstein coefficients, radiative lifetimes, and oscillator strengths. These properties concern as well valence and Rydberg states. For the valence states, only the (0, 0) band of the A 3 Pi-X 3 Sigma(-) transition has received some important amount of attention. Data for the other transitions are rather scarce and sometimes inexistent. The results obtained in this work show good agreement with the available experimental data in comparison to other theoretical numbers reported in the literature.

  8. The prospects of sympathetic cooling of NH molecules with Li atoms

    CERN Document Server

    Wallis, Alisdair O G; Zuchowski, Piotr S \\; Hutson, Jeremy M


    We calculate the quartet potential energy surface for Li+NH and use it to calculate elastic and spin-relaxation cross sections for collisions in magnetically trappable spin-stretched states. The potential is strongly anisotropic but spin-relaxation collisions are still suppressed by centrifugal barriers when both species are in spin-stretched states. In the ultracold regime, both the elastic and inelastic cross sections fluctuate dramatically as the potential is varied because of Feshbach resonances. The potential-dependence is considerably reduced at higher energies. The major effect of using an unconverged basis set in the scattering calculations is to shift the resonances without changing their general behaviour. We have calculated the ratio of elastic and spin-relaxation cross sections, as a function of collision energy and magnetic field, for a variety of potential energy surfaces. Most of the surfaces produce ratios that are favorable for sympathetic cooling, at temperatures below about 20 mK.

  9. Adsorption Mechanisms of NH{sub 3} on Chlorinated Si(100)-2 x 1 Surface

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Soon; Choi, Cheol Ho [Kyungpook National University, Daegu (Korea, Republic of)


    The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)- 2 x 1 surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a S{sub N}2 type transition state, which eventually leads to an HCl molecular desorption. The second ammonia molecule adsorption requires much less reaction barrier, which can be rationalized by the surface cooperative effect. In general, it was shown that the surface Si-Cl bonds can be easily subjected to the substitution reactions by ammonia molecules yielding symmetric surface Si-NH{sub 2} bonds, which can be a good initial template for subsequent surface chemical modifications. The ammonia adsorptions are in general more facile than the corresponding water adsorption, since ammonia is better nucleophile

  10. Low-energy electron impact cross-sections and rate constants of $NH_2$

    Indian Academy of Sciences (India)



    This systematic study reports various electron impact cross-sections, rate constants and transport properties of $NH_2$ radical in the low-energy limit. The collision study is based on $R$-matrix formalism and involves the use of various scattering models employing different active spaces. Both electron excited inelasticcross-sections and resonances are found influenced by correlation and polarization effects. The non-relativistic molecular bremsstrahlung radiation cross-section for soft photons, binary encounter Bethe model-based ionization cross-sections and a few molecular properties of the target radical are also reported. The present calculations are found to be in agreement with the available results. This theoretical study provides a pathway to understand collision dynamics and generates data required in various fields of applied physics.

  11. Intense Pulsed Light Sintering of CH3NH3PbI3 Solar Cells. (United States)

    Lavery, Brandon W; Kumari, Sudesh; Konermann, Hannah; Draper, Gabriel L; Spurgeon, Joshua; Druffel, Thad


    Perovskite solar cells utilizing a two-step deposited CH3NH3PbI3 thin film were rapidly sintered using an intense pulsed light source. For the first time, a heat treatment has shown the capability of sintering methylammonium lead iodide perovskite and creating large crystal sizes approaching 1 μm without sacrificing surface coverage. Solar cells with an average efficiency of 11.5% and a champion device of 12.3% are reported. The methylammonium lead iodide perovskite was subjected to 2000 J of energy in a 2 ms pulse of light generated by a xenon lamp, resulting in temperatures significantly exceeding the degradation temperature of 150 °C. The process opens up new opportunities in the manufacturability of perovskite solar cells by eliminating the rate-limiting annealing step, and makes it possible to envision a continuous roll-to-roll process similar to the printing press used in the newspaper industry.

  12. Determination of NH3 emissions from confined areas using backward Lagrangian stochastic dispersion modelling (United States)

    Häni, Christoph; Neftel, Albrecht; Sintermann, Jörg


    Employing backward Lagrangian stochastic (bLS) dispersion modelling to infer emission strengths from confined areas using trace gas concentration measurements is a convenient way of emission estimation from field measurements (see Wilson et al., 2012 and references therein). The freely available software 'WindTrax' (, providing a graphical interface for the application of a bLS model, has spurred its utilisation in the past decade. Investigations include mainly methane (CH4) and ammonia (NH3) emissions based on experimental plots with dimensions between approximately 102 to 104 m2. Whereas for CH4 deposition processes can be neglected, NH3 has a strong affinity to any surface and is therefore efficiently deposited. Neglecting dry deposition will underestimate NH3 emissions, e.g. with a standard WindTrax approach. We extended the bLS model described in Flesch et al. (2004) by a dry deposition process using a simple, one-directional deposition velocity approach. At every contact of the model trajectories with ground level (here at the height of the roughness length Zo), deposition is modelled as: Fdep = vdep × CT raj (1) where vdep represents deposition velocity, and CTraj is the actual concentration of the specific trajectory at contact. A convenient way to model vdep is given by a resistances approach. The deposition velocity is modelled as the inverse of the sum of a series of different resistances to deposition. The aerodynamic resistance is already implicitly included in the bLS model, thus vdep is given as: v = ---1--- dep Rb + Rc (2) Rb and Rc represent resistances of different model layers between Zo and the surfaces where deposition take place. With this approach we analysed a dataset from measurements with an artificial NH3 source that consisted of 36 individual orifices mimicking a circular area source with a radius of 10 m. The use of three open-path miniDOAS (Sintermann et al., submitted to AMT) systems allowed to measure

  13. The temperature dependence of second and higher order elastic constants of NH4Cl (United States)

    Tiwari, Alpana; Gaur, N. K.


    We have incorporated the translational rotational (TR) coupling effects in the framework of three body force shell model (TSM) to develop an extended TSM (ETSM). This ETSM has been applied to reveal the second order elastic constants (C11, C12 and C44) of NH4Cl as a function of temperature for temperature range 240K≤T≤440K. An abrupt decrease in C44 is observed due to disorder present in the crystal as a result of random orientations of tetrahedral ammonium molecule. Our calculated results show similar trend as revealed by experimental data. Besides third order elastic constants have also been studied and discussed as a function of temperature for 240K≤T≤440K.

  14. Nonadiabatic quantum dynamics calculations for the N + NH --> N(2) + H reaction. (United States)

    Yang, Huan; Hankel, M; Varandas, Antonio; Han, Keli


    Nonadiabatic quantum dynamics calculations on the two coupled potential energy surfaces (PESs) (1(2)A' and 2(2)A') and also adiabatic quantum calculations on the lowest adiabatic PES are reported for the title reaction. Reaction probabilities for total angular momenta, J, varying from 0 to 160, are calculated to obtain the integral cross section (ICS) for collision energies ranging from 0.05 to 1.0 eV. Calculations using both the close coupling and the Centrifugal Sudden (CS) approximation are carried out to evaluate the role of Coriolis coupling effects for this reaction. The results of the nonadiabatic calculations show that the nonadiabatic effects in the title reaction for the initial state of NH (v = 0, j = 0) could be neglected, at least in the collision energy range considered in this study.

  15. Lanthanide induced residual dipolar couplings for the conformational investigation of peripheral 15NH2 moieties

    Energy Technology Data Exchange (ETDEWEB)

    Bertini, Ivano; Felli, Isabella C. [University of Florence, Magnetic Resonance Center (CERM) (Italy); Luchinat, Claudio [University of Florence, Department of Soil Science and Plant Nutrition (Italy)


    The Ca{sub 2} calbindin protein in which one calcium has been substituted with Ce(III), Yb(III) and Dy(III) displays substantial alignment in high magnetic fields due to the high anisotropy of the metal magnetic susceptibility. This property has allowed the measurement of residual dipolar coupling contributions to {sup 1}J{sub HN}and {sup 2}J{sub HH} couplings of asparagine and glutamine NH{sub 2} moieties. Such data have been used to aid structural characterization of these groups. The exploitation of auto-orientation of magnetic anisotropic metalloproteins represents a step ahead in the investigation of the conformational space of peripheral residues that are not fixed by the protein folding.

  16. A near infrared line list for \\NH: Analysis of a Kitt Peak spectrum after 35 years

    CERN Document Server

    Barton, Emma J; Tennyson, Jonathan; Béguier, S; Campargue, A


    A Fourier Transform (FT) absorption spectrum of room temperature NH3 in the region 7400 - 8600 cm-1 is analysed using a variational line list and ground state energies determined using the MARVEL procedure. The spectrum was measured by Dr Catherine de Bergh in 1980 and is available from the Kitt Peak data center. The centers and intensities of 8468 ammonia lines were retrieved using a multiline fitting procedure. 2474 lines are assigned to 21 bands providing 1692 experimental energies in the range 7000 - 9000 cm-1. The spectrum was assigned by the joint use of the BYTe variational line list and combination differences. The assignments and experimental energies presented in this work are the first for ammonia in the region 7400 - 8600 cm-1, considerably extending the range of known vibrational-excited states

  17. 欧洲NH-90反潜/运输直升机

    Institute of Scientific and Technical Information of China (English)



    由欧洲NH工业公司主持的NH90直升机项目,系欧洲多国合作的新成果,“NH”是“北约直升机”(NATO Helicopter)的英文字头的缩写。原本该公司是一家合作公司,由意大利阿古斯塔·韦斯特兰公司(32%),欧洲直升机公司(62.5%),荷兰Fokker公司(5%)共同投资。其中的欧洲直升机公司是欧洲航宇防务(EADS)的一个附属公司。

  18. C-H and C-C activation of n -butane with zirconium hydrides supported on SBA15 containing N-donor ligands: [(≡SiNH-)(≡SiX-)ZrH2], [(≡SiNH-)(≡SiX-)2ZrH], and[(≡SiN=)(≡SiX-)ZrH] (X = -NH-, -O-). A DFT study

    KAUST Repository

    Pasha, Farhan Ahmad


    Density functional theory (DFT) was used to elucidate the mechanism of n-butane hydrogenolysis (into propane, ethane, and methane) on well-defined zirconium hydrides supported on SBA15 coordinated to the surface via N-donor surface pincer ligands: [(≡SiNH-)(≡SiO-)ZrH2] (A), [(≡SiNH-)2ZrH2] (B), [(≡SiNH-)(≡SiO-) 2ZrH] (C), [(≡SiNH-)2(≡SiO-)ZrH] (D), [(≡SiN=)(≡Si-O-)ZrH] (E), and [(≡SiN=)(≡SiNH-)ZrH] (F). The roles of these hydrides have been investigated in C-H/C-C bond activation and cleavage. The dihydride A linked via a chelating [N,O] surface ligand was found to be more active than B, linked to the chelating [N,N] surface ligand. Moreover, the dihydride zirconium complexes are also more active than their corresponding monohydrides C-F. The C-C cleavage step occurs preferentially via β-alkyl transfer, which is the rate-limiting step in the alkane hydrogenolysis. The energetics of the comparative pathways over the potential energy surface diagram (PES) reveals the hydrogenolysis of n-butane into propane and ethane. © 2014 American Chemical Society.

  19. Room temperature synthesis and structural characterization of (NH 4) 15Co 0.5(NH 3) 3[Co(NH 3) 4NaSb 9W 21O 86]·15H 2O—a novel chain-like inorganic cryptate (United States)

    Lihua, Bi; Enbo, Wang; Rudan, Huang; Changwen, Hu


    A novel one-dimensional infinite chain-like cryptate (NH4)15Co0.5(NH3)3[Co(NH3)4NaSb9W21O86]·15H2O (I) was synthesized at room temperature and characterized by elemental analyses, IR spectrum, UV spectrum, X-ray powder diffraction and X-ray crystal diffraction. It crystallized in the monoclinic system with space group P21/n, a=18.643(4), b=30.970(6), c=21.677(4) Å,β=91.58(3)°, V=12 510(4) Å3,Z=4 and Dc=3.772 g cm-3. It was constructed with building blocks, NaSb9W21O8618-, that were connected by bridging [Co(NH3)4]2+. NaSb9W21O8618-, which provides two terminal oxygen atoms as a didentate coordinates to [Co(NH3)4]2+ forming an extended structure along the [001] plane. This is the first example of a chain structure in which a cryptate anion acts as a ligand to coordinate to the Co(II) ion. The magnetic susceptibility, measured in a temperature range of 75-300 K, shows a weak antiferromagnetic character of this compound.

  20. Fabrication of metallic Cd multifarious prismatic microcrystals (CMPMCs) under NH{sub 3} gas ambient

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Waheed S. [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Cao, Chuanbao, E-mail: [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Butt, Faheem K.; Ali, Zulfiqar [Research Centre of Materials Science, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Baig, Anisullah [Department of Engineering-Applied Sciences, University of California, Davis, CA 95616 (United States); Ain, Qurrat ul; Iqbal, M. Zubair [Department of Physics, School of Physics and Mathematics, University of Science and Technology Beijing, Beijing 100083 (China); Sadaf, Asma [Advance Photonics Center, Southeast University, Nanjing 210096 (China); Shah, Sajjad H. [Department of Physics, Beijing Institute of Technology, Beijing 100081 (China)


    Highlights: > Cd prismatic microcrystals are prepared by thermal reduction of CdO under NH{sub 3} gas. > Vapour-solid (VS) process based growth mechanism governs the formation of CMPMCs. > PL spectrum for CMPMCs exhibits UV band at 365 nm and visible emission at 404 nm. > This study shows the potential of CMPMCs for applications in optical devices. - Abstract: We report here highly dense and pure metallic cadmium (Cd) multifarious prismatic microcrystals (CMPMCs) fabricated by thermal decomposition of cadmium oxide (CdO) powder at 700 deg. C for 60 min under NH{sub 3} gas ambient inside horizontal tube furnace. CMPMCs were observed to be 1-1.5 {mu}m in size with interesting morphologies of various cross sections such as triangular, trapezoidal, pentagonal and hexagonal etc. having solid, hollow/semi-hollow appearances. The as-synthesized CMPMCS were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Room temperature photoluminescence (PL) spectrum for Cd metal microcrystals exhibited a prominent emission band at 365 along with a shoulder peak at 404 nm. The UV main emission band is ascribed to radiative recombination of the electrons in the s, p conduction band near the Fermi surface and holes in the d bands generated under xenon light excitation whereas shoulder peak may be owing to surface oxidation effects or induced defects. This study shows the potential of CMPMCs for applications in optical devices. Based on vapour-solid (VS) process, growth mechanism for the formation of CMPMCs is also proposed and discussed briefly.

  1. C-H and N-H bond dissociation energies of small aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Barckholtz, C.; Barckholtz, T.A.; Hadad, C.M.


    A survey of computational methods was undertaken to calculate the homolytic bond dissociation energies (BDEs) of the C-H and N-H bonds in monocyclic aromatic molecules that are representative of the functionalities present in coal. These include six-membered rings (benzene, pyridine, pyridazine, pyrimidine, pyrazine) and five-membered rings (furan, thiophene, pyrrole, oxazole). By comparison of the calculated C-H BDEs with the available experimental values for these aromatic molecules, the B3LYP/6-31G(d) level of theory was selected to calculate the BDEs of polycyclic aromatic hydrocarbons (PAHs), including carbonaceous PAHs (naphthalene, anthracene, pyrene, coronene) and heteroatomic PAHs (benzofuran, benzothiophene, indole, benzoxazole, quinoline, isoquinoline, dibenzofuran, carbazole). The cleavage of a C-H or a N-H bond generates a {sigma} radical that is, in general, localized at the site from which the hydrogen atom was removed. However, delocalization of the unpaired electron results in {approximately} 7 kcal {center{underscore}dot} mol{sup {minus}1} stabilization of the radical with respect to the formation of phenyl when the C-H bond is adjacent to a nitrogen atom in the azabenzenes. Radicals from five-membered rings are {approximately} 6 kcal {center{underscore}dot} mol{sup {minus}1} less stable than those formed from six-membered rings due to both localization of the spin density and geometric factors. The location of the heteroatoms in the aromatic ring affects the C-H bond strengths more significantly than does the size of the aromatic network. Therefore, in general, the monocyclic aromatic molecules can be used to predict the C-H BDE of the large PAHs within 1 kcal {center{underscore}dot} mol{sup {minus}1}.

  2. Statistic Reliability of the Meso-Nh Atmospherical Model for 3D CN2 simulations

    Directory of Open Access Journals (Sweden)

    E. Masciadri


    Full Text Available La técnica numérica es, actualmente, la única metodología que puede proporcionar mapas en 3D de C2 N en una región alrededor de un telescopio. Estudios anteriores han demostrado que el modelo atmosférico no-hidrostático Meso-Nh puede simular perfiles verticales de C2 N confiables. Recientemente, se ha propuesto una nueva técnica de calibración para el modelo para mejorar la confiabilidad de las simulaciones. Con el fin de estudiar la confiabilidad estadística, en este trabajo se aplica dicha técnica a una muestra de 10 noches de la campaña de estudio de sitio de San Pedro Mártir, llevada a cabo en mayo del 2000. Las medidas de los perfiles de C2N proporcionadas por diversos instrumentos se comparan con simulaciones y los resultados se analizan estadísticamente después de la calibración. Por primera vez, la comparación entre las medidas y las simulaciones se realiza considerando las contribuciones de la turbulencia proporcionadas por todas las regiones de la atmósfera (capa límite, atmósfera libre y capa superficial y por la cúpula del telescopio. Los resultados demuestran que la dispersión entre las medidas y las simulaciones es comparable a la dispersión obtenida entre las medidas proporcionadas por diversos instrumentos (el error relativo para la campaña completa es 30% en ambos casos. Se presentan sugerencias para mejoras que se pueden implementar en el modelo Meso-Nh.

  3. Crystal structure of (NH42[FeII5(HPO36], a new open-framework phosphite

    Directory of Open Access Journals (Sweden)

    Teresa Berrocal


    Full Text Available Diammonium hexaphosphitopentaferrate(II, (NH42[Fe5(HPO36], was synthesized under mild hydrothermal conditions and autogeneous pressure, yielding twinned crystals. The crystal structure exhibits an [FeII5(HPO36]2− open framework with NH4+ groups as counter-cations. The anionic skeleton is based on (001 sheets of [FeO6] octahedra (one with point-group symmetry 3.. and one with .2. linked along [001] through [HPO3]2− oxoanions. Each sheet is constructed from 12-membered rings of edge-sharing [FeO6] octahedra, giving rise to channels with a radius of ca 3.1 Å in which the disordered NH4+ cations are located. The IR spectrum shows vibrational bands typical for phosphite and ammonium groups.

  4. CH3NH3PbI3, A Potential Solar Cell Candidate: Structural and Spectroscopic Investigations. (United States)

    Nandi, Pronoy; Giri, Chandan; Joseph, Boby; Rath, S; Manju, U; Topwal, D


    Hybrid organic-inorganic metal halides of the type CH3NH3PbX3 have emerged as potential materials for photovoltaic applications. In this paper we discuss structural, electronic, and optical spectroscopy investigations performed on high quality single crystals of CH3NH3PbI3. Our results conclusively suggest that CH3NH3PbI3 crystallizes in centrosymmetric space group and the methylammonium moiety exhibits disordered packing at room temperature. Extracted values of the exciton binding energy, the electron-phonon coupling constant, and the schematic energy level diagram constructed from the emission broadening, Raman, and photoemission spectroscopy measurements clearly show the potential of this system in photovoltaic applications.

  5. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry

    KAUST Repository

    Alias, Mohd Sharizal


    The lack of optical constants information for hybrid perovskite of CH3NH3PbBr3 in thin films form can delay the progress of efficient LED or laser demonstration. Here, we report on the optical constants (complex refractive index and dielectric function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained from photoluminescence and spectrophotometry spectra, and calculated from the SE analysis. The precise measurement of optical constants will be useful in designing optical devices using CH3NH3PbBr3 thin films.

  6. Calculation of the Specific Heats for the H-M and E-IV Phase Transitions in NH4I

    Institute of Scientific and Technical Information of China (English)

    H. Yurtseven; H. Kaya


    This study gives our calculation for the specific heats Cvi due to an Ising model using the observed Cp data for the JT-JZT and JL-TV phase transitions in NH^I. By fitting to the Cp data we determine the values of the critical exponent for the pressure of 0.14GPa (H-M phase transition) and for the pressures of 0.75, 1.35 and 1.97GPa (E-HV phase transition) in NH^I. Our exponent values are close to the predicted values of the specific heat in a three-dimensional Ising model. Our calculated Cyi are in good agreement with the experimental Cp for NH^I in most cases.

  7. Investigation of Influence NH4VO3+HOCH2CH2OH Oxidation of ASD-4 Powder (United States)

    Shevchenko, V.; Eselevich, D.; Krasilnikov, V.; Konyukova, A.; Ancharov, A.; Tolochko, B.; Zolotarev, K.

    The thermokinetic data on the process of oxidation, of NH4VO3 + HOCH2CH2OH modified ASD-4 powder have been obtained by the TG and DSC methods during heating in air up to 1473 K at a rate of 10 K / min. The process of phase formation was studied directly during oxidation of the modified ASD-4 powder under similar conditions by the X-ray diffraction method using a synchrotron radiation from the VEPP-3 station of Channel 4 on the basis of equipment available at ISSCM SB RAS. It was found that oxidation of the activated powders is shifted into the low temperature region. Two modifiers: NH4VO3 + HOCH2CH2OH and previously examined V2O5 nH2O were compared.

  8. Theoretical Studies on Dehydrogenation Reactions in Mg2(BH4)2(NH2)2 Compounds

    Institute of Scientific and Technical Information of China (English)

    Zheng Chen; Zhe-ning Chen; An-an Wu; Guo-tao Wu; Zhi-tao Xiong; Ping Chen; Xin Xu


    Borohydrides have been recently hightlighted as prospective new materials due to their high gravimetric capacities for hydrogen storage.It is,therefore,important to understand the underlying dehydrogenation mechanisms for further development of these materials.We present a systematic theoretical investigation on the dehydrogenation mechanisms of the Mg2(BH4)2(NH2)2 compounds.We found that dehydrogenation takes place most likely via the intermolecular process,which is favorable both kinetically and thermodynamically in comparison with that of the intramolecular process.The dehydrogenation of Mg2(BH4)2(NH2)2 initially takes place via the direct combination of the hydridic H in BH4-and the protic H in NH2-,followed by the formation of Mg-H and subsequent ionic recombination of Mg-Hδ-… Hδ+-N.

  9. Correlation between ionic conductivity and fluidity of polymer gel electrolytes containing NH4CF3SO3

    Indian Academy of Sciences (India)

    Harinder Pal Singh; Rajiv Kumar; S S Sekhon


    Nonaqueous polymer gel electrolytes containing ammonium triflate (NH4CF3SO3) and dimethylacetamide (DMA) with polymethylmethacrylate (PMMA) as the gelling polymer have been synthesized which show high value of conductivity (∼ 10-2 S/cm) at 25°C. The conductivity of polymer gel electrolytes containing different concentrations of NH4CF3SO3 shows a small decrease with the addition of PMMA and this has been correlated with the variation of fluidity of these gel electrolytes. The small decrease in conductivity with PMMA addition shows that polymer plays the role of stiffener and this is supported by FTIR results which also indicates the absence of any active interaction between polymer and NH4CF3SO3 in these gel electrolytes.

  10. Doping effect on the adsorption of NH3 molecule onto graphene quantum dot: From the physisorption to the chemisorption (United States)

    Seyed-Talebi, Seyedeh Mozhgan; Beheshtian, J.; Neek-amal, M.


    The adsorption of ammonia molecule onto a graphene hexagonal flake, aluminum (Al) and boron (B) doped graphene flakes (graphene quantum dots, GQDs) are investigated using density functional theory. We found that NH3 molecule is absorbed to the hollow site through the physisorption mechanism without altering the electronic properties of GQD. However, the adsorption energy of NH3 molecule onto the Al- and B-doped GQDs increases with respect GQD resulting chemisorption. The adsorption of NH3 onto the Al-doped and B-doped GQDs makes graphene locally buckled, i.e., B- doped and Al-doped GQDs are not planar. The adsorption mechanism onto a GQD is different than that of graphene. This study reveals important features of the edge passivation and doping effects of the adsorption mechanism of external molecules onto the graphene quantum dots.

  11. Surface-exchange of NOx and NH3 above a winter wheat field in the Yangtze Delta, China

    Institute of Scientific and Technical Information of China (English)

    FANG Shuan-gxi; ZHANG Yi; MU Yu-jing


    A four-dynamic-chamber system was constructed to measure NOx and NH3 surface-exchange between a typical wheat field and the fluxes of NO2 and NH3 were negatively correlated with their ambient concentrations during the investigated period. The compensation point of NO2 between the wheat field and the atmosphere was 11.9 μg/m3. The emissions of NO-N and NH3-N from the urea applied to the wheat field were 2.3% and 0.2%, respectively, which indicated that the main pathway of N loss from the investigated winter wheat field was NO. Application of a mixture of urea and lignin increased the emissions of NO, but also greatly increased the yield of the winter wheat.

  12. The solid solution Na0.39(NH41.61SO4·Te(OH6

    Directory of Open Access Journals (Sweden)

    Abdelwaheb Kolsi


    Full Text Available The title compound, sodium ammonium sulfate–telluric acid (1/1, Na0.39(NH41.61SO4·Te(OH6, is isostructural with other solid solutions in the series M1−x(NH4xSO4·Te(OH6, where ammonium is partially replaced with an alkali metal (M = K, Rb or Cs. The structure is composed of planes of Te(OH6 octahedra alternating with planes of SO4 tetrahedra. The Na+/NH4+ cations are statistically distributed over the same position and are located between the planes. The structure is stabilized by O—H...O and N—H...O hydrogen bonds between the telluric acid adducts and the O atoms of sulfate groups, and between the ammonium cations and O atoms, respectively. Both Te atoms lie on centres of symmetry.

  13. Ice rink installations working with natural refrigerants; Kunst-ijsbanen met NH3 en CO2, natuurlijker kan het niet

    Energy Technology Data Exchange (ETDEWEB)

    Berends, E. [Grenco, Den Bosch (Netherlands)


    In a growing number of countries it is not allowed anymore to use big amounts of ammonia in areas occupied by many people. So new skating halls with direct ammonia systems are not built anymore although those systems are the best solution, concerning ice quality and energy consumption. An indirect system NH3/glycol or brine uses circa 20% more energy. By using (H)CFC's instead of NH3 the energy consumption might even be higher. During the last years CO2 has proven itself not only as an excellent refrigerant but also as a very usable secondary refrigerant in stead of brines, etc. In this article the successful application of the newly developed NH3/CO2 system on an existing ice rink is described. [Dutch] Een overzicht wordt gegeven van de voordelen en de nadelen van verschillende koelmiddelen voor kunstijsbanen in Nederland (ammoniak, CO2, glycol)

  14. Resonances in rotationally inelastic scattering of NH{sub 3} and ND{sub 3} with H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qianli; Dagdigian, Paul J., E-mail: [Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685 (United States); Avoird, Ad van der, E-mail:; Meerakker, Sebastiaan Y. T. van de [Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Loreau, Jérôme [Service de Chimie Quantique et Photophysique C. P. 160/09, Université Libre de Bruxelles (ULB), 50 Ave. F. D. Roosevelt, 1050 Brussels (Belgium); Alexander, Millard H., E-mail: [Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2021 (United States)


    We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH{sub 3} and ND{sub 3} molecules with H{sub 2} molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH{sub 3}/ND{sub 3}–H{sub 2} system for collision energies between 5 and 70 cm{sup −1}, using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To analyze these, we use an adiabatic bender model, as well as examination at the scattering wave functions and lifetimes. The strength and width of the resonance peaks suggest that they could be observed in a crossed molecular beam experiment involving a Stark-decelerated NH{sub 3} beam.

  15. Fluorescence Excitation Models of Ammonia and Amidogen Radical (NH2) in Comets: Application to Comet C/2004 Q2 (Machholz) (United States)

    Kawakita, Hideyo; Mumma, Michael J.


    Ammonia is a major reservoir of nitrogen atoms in cometary materials. However, detections of ammonia in comets are rare, with several achieved at radio wavelengths. A few more detections were obtained through near-infrared observations (around the 3 m wavelength region), but moderate relative velocity shifts are required to separate emission lines of cometary ammonia from telluric absorption lines in the 3 micron wavelength region. On the other hand, the amidogen radical (NH2 -- a photodissociation product of ammonia in the coma) also shows rovibrational emission lines in the 3 micron wavelength region. Thus, gas production rates for ammonia can be determined from the rovibrational emission lines of ammonia (directly) and amidogen radical (indirectly) simultaneously in the near-infrared. In this article, we present new fluorescence excitation models for cometary ammonia and amidogen radical in the near-infrared, and we apply these models to the near-infrared high-dispersion spectra of comet C/2004 Q2 (Machholz) to determine the mixing ratio of ammonia to water in the comet. Based on direct detection of NH3 lines, the mixing ratio of NH3/H2O is 0.46% +/- 0.03% in C/2004 Q2 (Machholz), in agreement with other results. The mixing ratio of ammonia determined from the NH2 observations (0.31% -- 0.79%) is consistent but has relatively larger error, owing to uncertainty in the photodissociation rates of ammonia. At the present level of accuracy, we confirm that NH3 could be the sole parent of NH2 in this comet.

  16. Investigation of Catalytic Effects and Compositional Variations in Desorption Characteristics of LiNH2-nanoMgH2

    Directory of Open Access Journals (Sweden)

    Sesha S. Srinivasan


    Full Text Available LiNH2 and a pre-processed nanoMgH2 with 1:1 and 2:1 molar ratios were mechano-chemically milled in a high-energy planetary ball mill under inert atmosphere, and at room temperature and atmospheric pressure. Based on the thermogravimetric analysis (TGA experiments, 2LiNH2-nanoMgH2 demonstrated superior desorption characteristics when compared to the LiNH2-nanoMgH2. The TGA studies also revealed that doping 2LiNH2-nanoMgH2 base material with 2 wt. % nanoNi catalyst enhances the sorption kinetics at lower temperatures. Additional investigation of different catalysts showed improved reaction kinetics (weight percentage of H2 released per minute of the order TiF3 > nanoNi > nanoTi > nanoCo > nanoFe > multiwall carbon nanotube (MWCNT, and reduction in the on-set decomposition temperatures of the order nanoCo > TiF3 > nanoTi > nanoFe > nanoNi > MWCNT for the base material 2LiNH2-nanoMgH2. Pristine and catalyst-doped 2LiNH2-nanoMgH2 samples were further probed by X-ray diffraction, Fourier transform infrared spectroscopy, transmission and scanning electron microscopies, thermal programmed desorption and pressure-composition-temperature measurements to better understand the improved performance of the catalyst-doped samples, and the results are discussed.

  17. Transport of Nitrogen Assimilation in Xylem Vessels of Green Tea Plants Fed with NH4-N and NO3-N

    Institute of Scientific and Technical Information of China (English)

    K.OH; T.KATO; H.L.XU


    An experiment was carried out to study the transport process of nitrogen (N) assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15N-NO3 and 15N-NH4 were fed to the root of tea plants (Camellia sinensis L.).Results showed that the main amino acids were glutamine,theanine,arginine,asparic acid and glutamic acid,which accounted for 49e/0,17%,8%,7%,and 4%,respectively,of the total amino acids in the xylem sap.After the tea plants were fed with 15N-NO3 and 15N-NH4 for 48 h,the amount of total amino acids in xylem sap significantly increased and those fed with 15N-NH4 had higher increment than those with 15N-NO3.Two hours after 15N-NO3 and 15N-NH4 were fed,15N abundance in glutamine,asparagine,glutaxnic acid,aianine,and arginine were detected and increased quickly over time.This indicated that it took less than 2 h for NO3-N and NH4-N to be absorbed by tea roots,incorporated into the above amino acids and transported to the xylem sap.Rapid increase in 15N-NO3 in the xylem sap of tea plants fed with 15N-NO3 indicated that nitrate could be directly transported to the xylem sap.Glutamine,theanine,and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15N-NO3 and 15N-NH4.

  18. Release of HCN, NH{sub 3} and HNCO from the thermal gas-phase cracking of coal pyrolysis tars

    Energy Technology Data Exchange (ETDEWEB)

    Ledesma, E.B.; Li, C.-Z.; Nelson, P.F.; Mackie, J.C. [CSIRO, North Ryde, NSW (Australia). Division of Coal and Energy Technology


    The release of HCN, NH{sub 3} and HNCO from the thermal cracking of coal tars produced by rapid pyrolysis has been investigated using a quartz fluidized-bed reactor coupled to a quartz tubular-flow reactor. Primary pyrolysis at 600{degree}C in the fluidized-bed reactor generated the tars which were subsequently thermally decomposed in the tubular reactor in the temperature range of 600-1000{degree}C. HNCO was the initial gaseous N-containing species to be evolved, its formation commencing from 600{degree}C. HNCO was found to be a significant N-containing product of tar cracking and some previous measurements of NH{sub 3} yields during coal pyrolysis are probably the sum of the yields of NH{sub 3} and HNCO. Both HCN and NH{sub 3} start to appear from above 700{degree}C. While NH{sub 3} reaches a maximum at 850{degree}C, HCN continues to increase at higher temperatures. It is suggested that NH{sub 3} may be formed from the interactions of N-containing species with donatable H on the soot surface. FTIR analyses of the tars demonstrate that increases in the temperature of pyrolysis result in a decrease in aromatic substitution. Kinetic parameters for the release of tar-N species as HCN were determined by measurement of HCN yields and by assuming that the reaction was first order in tar-N. An overall global rate expression of 10{sup 6} exp(-140 {+-} 15/RT)s{sup -1} was derived from the data. The rate expression suggests that nitrogen release during tar cracking is a complex process. 31 refs., 7 figs., 1 tab.

  19. Two-stage biofilter for effective NH3 removal from waste gases containing high concentrations of H2S. (United States)

    Chung, Ying-Chien; Ho, Kuo-Ling; Tseng, Ching-Ping


    A high H2S concentration inhibits nitrification when H2S and NH3 are simultaneously treated in a single biofilter. To improve NH3 removal from waste gases containing concentrated H2S, a two-stage biofilter was designed to solve the problem. In this study, the first biofilter, inoculated with Thiobacillus thioparus, was intended mainly to remove H2S and to reduce the effect of H2S concentration on nitrification in the second biofilter, and the second biofilter, inoculated with Nitrosomonas europaea, was to remove NH3. Extensive studies, which took into account the characteristics of gas removal, the engineering properties of the two biofilters, and biological parameters, were conducted in a 210-day operation. The results showed that an average 98% removal efficiency for H2S and a 100% removal efficiency for NH3 (empty bed retention time = 23-180 sec) were achieved after 70 days. The maximum degradation rate for NH3 was measured as 2.35 g N day(-1) kg of dry granular activated carbon(-1). Inhibition of nitrification was not found in the biofilter. This two-stage biofilter also exhibited good adaptability to shock loading and shutdown periods. Analysis of metabolic product and observation of the bacterial community revealed no obvious acidification or alkalinity phenomena. In addition, a lower moisture content (approximately 40%) for microbial survival and low pressure drop (average 24.39 mm H2O m(-1)) for system operation demonstrated that the two-stage biofilter was energy saving and economic. Thus, the two-stage biofilter is a feasible system to enhance NH3 removal in the concentrated coexistence of H2S.

  20. Scattering of NH{sub 3} and ND{sub 3} with rare gas atoms at low collision energy

    Energy Technology Data Exchange (ETDEWEB)

    Loreau, J., E-mail: [Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB) CP 160/09, 50 av. F.D. Roosevelt, 1050 Brussels (Belgium); Avoird, A. van der, E-mail: [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)


    We present a theoretical study of elastic and rotationally inelastic collisions of NH{sub 3} and ND{sub 3} with rare gas atoms (He, Ne, Ar, Kr, Xe) at low energy. Quantum close-coupling calculations have been performed for energies between 0.001 and 300 cm{sup −1}. We focus on collisions in which NH{sub 3} is initially in the upper state of the inversion doublet with j = 1, k = 1, which is the most relevant in an experimental context as it can be trapped electrostatically and Stark-decelerated. We discuss the presence of resonances in the elastic and inelastic cross sections, as well as the trends in the inelastic cross sections along the rare gas series and the differences between NH{sub 3} and ND{sub 3} as a colliding partner. We also demonstrate the importance of explicitly taking into account the umbrella (inversion) motion of NH{sub 3} in order to obtain accurate scattering cross sections at low collision energy. Finally, we investigate the possibility of sympathetic cooling of ammonia using cold or ultracold rare gas atoms. We show that some systems exhibit a large ratio of elastic to inelastic cross sections in the cold regime, which is promising for sympathetic cooling experiments. The close-coupling calculations are based on previously reported ab initio potential energy surfaces for NH{sub 3}–He and NH{sub 3}–Ar, as well as on new, four-dimensional, potential energy surfaces for the interaction of ammonia with Ne, Kr, and Xe, which were computed using the coupled-cluster method and large basis sets. We compare the properties of the potential energy surfaces corresponding to the interaction of ammonia with the various rare gas atoms.

  1. Modelling study of dielectric barrier glow discharge in Ar/NH3 mixture at atmospheric pressure%大气压Ar/NH3介质阻挡辉光放电的仿真研究

    Institute of Scientific and Technical Information of China (English)

    张增辉; 张冠军; 邵先军; 常正实; 彭兆裕; 许昊


    为了研究火气压下氩气(Ar)中掺杂氨气(NH3)的Ar/NH3介质阻挡辉光放电的放电机理,通过建立一‘个多粒子的自洽耦合流体模型,采用有限元方法进行数值计算,得到了气体间隙压降、介质表面电荷密度、放电电流密度随时间的周期变化波形,以及带电粒子、中性粒子与空间电场强度的时空分布.仿真计算结果表明:气体间隙的周期击穿过程主要由气隙电压控制,并受气隙两侧介质极板上积聚的表面电荷的影响.气隙间带电粒子密度和电场强度的时空分布表明本文的放电过程存在阴极位降区、负辉区、法拉第暗区、等离子体正柱区等辉光放电的典型区域,放电模式为大气压辉光放电.在Ar/NH3等离子体中,主要的正离子为NH+,其次为Ar2+,主要的负离子为NHi:NH3分解产生的主要的激发态分子为NH,NH2和N2H3,而最终的稳态产物主要是N2和H2.%In order to investigate the mechanism of dielectric barrier glow discharge in Ar/NH3 mixture at atmospheric pressure, a multiple particles self-consistent coupled fluid model is proposed. And the finite-element method is used in the numerical calculation model, so the periodically varying waveforms of gas voltage, dielectric surface charge density and discharge current density are investigated. The spatial and temporal distributions of charged and neutral particles density and space electrical field strength are also obtained. The simulation results show that the periodic breakdown process of the gas gap is controlled by the gas voltage, and affected by dielectric surface charges. The spatiotemporal distributions of charged particle density and electrical field strength show that the discharge under conditions considered in this model is a typical atmospheric pressure glow discharge, and that in the discharge process there exist an obvious cathode fall region, a negative glow region, a

  2. First principle study of electronic and optical properties of molecular ion (BF4- ) substituted hybrid perovskite (CH3NH3PbI3) (United States)

    Rani, Shalu; Singh, Poorva


    Hybrid organic/inorganic perovskites have garnered significant research interest due to the extraordinary increase in energy conversion efficiency as witnessed in photovoltaic devices based on CH3NH3PbI3. An experimental report has shown that the substitution of BF4- in the perovskite CH3NH3PbI3 can lead to the high efficiency for solar cell. Employing first-principles calculations based on density functional theory, we have studied several different perovskites CH3NH3PbI3 , CH3NH3PbI2BF4, CH3NH3PbI(BF4)2, CH3NH3Pb(BF4)3 and examined their electronic structure and optical properties.

  3. Separation of H2S and NH3 gases from tofu waste water-based biogas using activated carbon adsorption (United States)

    Harihastuti, Nani; Purwanto, P.; Istadi, I.


    Research on the separation of H2S and NH3 gases from tofu waste water-based biogas has been conducted to improve the content of CH4 of biogas in order to increase calorific value. Biogas from tofu waste water contained many kinds of gases such as: CH4 of 53-64%, CO2 of 36-45%, H2S of 3,724-5,880 mg/Nm3, NH3 of 0.19-70.36 mg/Nm3, and H2O of 33,800-19,770,000 mg/Nm3. In fact, CO2, H2S, NH3, and moisture are impurities that have disturbance to human and environment, so that they are necessary to be separated from biogas. Particularly, H2S and NH3 have high toxicity to people, particularly the workers in the tofu industry. Therefore, separation of H2S and NH3 from biogas to increase calorific value is the focus of this research. The method used in this research is by adsorption of H2S and NH3 gases using activated carbon as adsorbent. It also used condensation as pretreatment to remove moisture content in biogas. Biogas was flowed to adsorption column (70 cm height and 9 cm diameter containing activated carbon as much as 500 g) so that the H2S and NH3 gases were adsorbed. This research was conducted by varying flow rate and flow time of biogas. From this experiment, it was found that the optimum adsorption conditions were flow rate of 3.5 l/min and 4 hours flow time. This condition could reach 99.95% adsorption efficiency of H2S from 5,879.50 mg/Nm3 to 0.67 mg/Nm3, and 74.96% adsorption efficiency of NH3 from 2.93 mg/Nm3 to 0.73 mg/Nm3. The concentration of CH4 increased from 63.88% to 76.24% in the biogas.

  4. Stimulated emission pumping of NH in flames by using two-color resonant four-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Radi, P.P.; Frey, H.M.; Mischler, B.; Tzannis, A.P.; Beaud, P.; Gerber, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    In this work we examine the analytical potential of two-color resonant four-wave mixing for the determination and characterization of trace elements in a combustion environment. Experimental results for NH in flames at atmospheric pressure are presented. The selectivity of the technique is used to simplify the Q-branch region of the (0-0)A{sup 3}{Pi}-X{sup 3}{Sigma} vibronic transition of NH. In addition, we demonstrate that the technique is sensitive to state changing collisions. (author) 2 figs., 5 refs.

  5. Calculation of H2O-NH3-CO2 Vapor Liquid Equilibria at High Concentration Conditions

    Institute of Scientific and Technical Information of China (English)

    魏顺安; 张红晶


    A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.

  6. Low Temperature Performance of Selective Catalytic Reduction of NO with NH3 under a Concentrated CO2 Atmosphere


    Xiang Gou; Chunfei Wu; Kai Zhang; Guoyou Xu; Meng Si; Yating Wang; Enyu Wang; Liansheng Liu; Jinxiang Wu


    Selective catalytic reduction of NOx with NH3 (NH3-SCR) has been widely investigated to reduce NOx emissions from combustion processes, which cause environmental challenges. However, most of the current work on NOx reduction has focused on using feed gas without CO2 or containing small amounts of CO2. In the future, oxy-fuel combustion will play an important role for power generation, and this process generates high concentrations of CO2 in flue gas. Therefore, studies on the SCR process unde...

  7. Biochar applied at an appropriate rate can avoid increasing NH3 volatilization dramatically in rice paddy soil. (United States)

    Feng, Yanfang; Sun, Haijun; Xue, Lihong; Liu, Yang; Gao, Qian; Lu, Kouping; Yang, Linzhang


    Biochar application can increase carbon sequestration and reduce greenhouse gases emissions in paddy soils. However, its influence on ammonia (NH3) volatilization is neglected. This soil column study was conducted using two biochars (wheat straw pyrolyzed at 500 °C and 700 °C) with two application rates (0.5 wt% and 3 wt%) to evaluate their impact on NH3 volatilization from rice paddy. Results showed that biochar application did not change NH3 volatilization fluxes pattern after N fertilization. Four biochar treatments recorded higher NH3 volatilization (20.50-31.88 kg N ha(-1)) compared with the control (18.65 kg N ha(-1)). Especially, two 3 wt% biochar treatments had significantly 40.8-70.9% higher NH3 volatilization than control. After the basal and first supplementary fertilization, the floodwater pH values were 7.61-7.79 and 7.51-7.76 under biochar treatments, higher than control (7.37 and 7.16, respectively). Meanwhile, after three split N fertilizations, the pH of surface soil received biochar increased by 0.19-0.45, 0.19-0.39, and 0.01-0.21 units, in comparison with the control soil. Furthermore, 3 wt% biochar treatments had higher floodwater and surface soil pH values than 0.5 wt% biochar treatments. Higher NH4(+)-N and lower NO3(-)-N concentrations of surface soil under biochar application were observed compared with control at tillering stage, whereas they were at similar level at jointing stage. The increased NH3 volatilization at 3 wt% biochar treatments is attributed to increased pH of surface floodwater and soil, and reduced nitrification processes induced by biochar application. Biochar should be applied at lower rate to rice paddy soil, considering the NH3 volatilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Synthesis and Characterization of Ethylenediammonium Molybdenum Thiocomplex [-H3NCH2CH2NH3] [Mo3Si3

    Institute of Scientific and Technical Information of China (English)

    WANG, Yimg; CHEN, Jie-Sheng; YUAN, Hong-Ming; SHI, 7han; YU, Shao-Fang; CHEN, Wei


    An organo-sfaced molybdenum thiocomples[H3NCH2CH2NH3] [Mo3S13]had been synthesized under hydrothermal condition and the structure of the compound was determined bysingle-crystal X-ray diffraction.The title compound crystalμ3-sulfur atom,with each Mo atom being also coordinated toome terminal disulfur ligand and two bridging disulfur ligands.The negativi charges on the inorganic cluster are balanced bythe ciprotonated ethylenediamine cations [H3NCH2CH2-NH3]2+located in the space between the clusters. N~-

  9. Isolation of pyroGlu-Gly-Arg-Phe-NH2 (Antho-RFamide), a neuropeptide from sea anemones

    DEFF Research Database (Denmark)

    Grimmelikhuijzen, C J; Ebbesen, Ditte Graff


    elegantissima. Three different methods established that the structure of the Anthopleura RFamide peptide (Antho-RFamide) is pyroGlu-Gly-Arg-Phe-NH2. Comparison of synthetic and natural Antho-RFamide and their enzymatic breakdown products on six different HPLC columns confirmed the structure of the sea anemone......A radioimmunoassay has been developed for peptides containing the carboxyl-terminal sequence Arg-Phe-NH2 (RFamide). Using this radioimmunoassay and applying cation-exchange chromatography and HPLC, we have isolated an RFamide peptide from acetic acid extracts of the sea anemone Anthopleura...

  10. Effects of SbBr3 addition to CH3NH3PbI3 solar cells (United States)

    Oku, Takeo; Ohishi, Yuya; Suzuki, Atsushi


    TiO2/CH3NH3Pb1-xSbxI3-2xBr3x-based photovoltaic devices were fabricated, and effects of SbBr3 addition to CH3NH3PbI3 precursor solutions on the photovoltaic properties were investigated. The short-circuit current densities and photoconversion efficiencies were improved by adding a small amount of SbBr3 to the perovskite phase, which would be due to a doping effect of Sb or Br atoms at the Pb or I sites.

  11. Selective catalytic reduction of NOx with NH3 over a Cu-SSZ-13 catalyst prepared by a solid state ion exchange method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Di; Gao, Feng; Peden, Charles HF; Li, Junhui; Kamasamudram, Krishna; Epling, William S.


    A novel solid state method was developed to synthesize Cu-SSZ-13 catalysts with excellent NH3-SCR performance and durable hydrothermal stability. After the solid state ion exchange (SSIE) process, the SSZ framework structure and surface area was maintained. In-situ DRIFTS and NH3-TPD experiments provide evidence that isolated Cu ions were successfully exchanged into the pores, which are the active centers for the NH3-SCR reaction.

  12. Top-Down Constraints on Air Quality Model Emissions of NH3, NOx, and SO2 using Surface, Aircraft, and Satellite Data (United States)

    Alvarado, M. J.; Lonsdale, C. R.; Winijkul, E.; Brodowski, C. M.; Cady-Pereira, K.; Henze, D. K.; Capps, S.


    Accurate modeling of the formation of ozone (O3) and fine particulate matter (PM2.5) requires accurate estimates of the emissions of precursor species such as ammonia (NH3), nitrogen oxides (NOx = NO+NO2) and sulfur dioxide (SO2). Here we present an evaluation of the 2011 EPA National Emission Inventory for NH3, NOx, and SO2 using CMAQv5.0.2 and data from the 2013 NOAA Southeast Nexus (SENEX) field campaign. Model results are compared to surface and aircraft measurements during each campaign, as well as satellite NH3 observations from the NOAA Cross-track Infrared Sounder (CrIS) and satellite observations of NO2 and SO2 from the NASA Ozone Monitoring Instrument (OMI). We also present an evaluation of the California Air Resources Board (CARB) NH3 emissions for 2012 using CMAQ and the CrIS NH3 observations. We discuss the lessons learned in using CrIS NH3 observations in the southeast US, where CMAQ predicts most of the gas-phase NH3 is very close to the surface, and contrast this with the use of CrIS NH3 observations over California. We discuss the use of two methods - a mass balance approach and an approach using the CMAQ adjoint - to optimize these emissions and evaluate the improvement in model performance for gas-phase NH3, NOx, and SO2, as well as for the formation of O3 and PM2.5.

  13. Identification of a transport mechanism for NH4+ in the symbiosome membrane of pea root nodules

    DEFF Research Database (Denmark)

    Mouritzen, P.; Rosendahl, L.


    Symbiosome membrane vesicles, facing bacteroid-side-out, were purified from pea (Pisum sativum L.) root nodules and used to study NH4+ transport across the membrane by recording vesicle uptake of the NH4+ analog [C-14]methylamine (MA). Membrane potentials (Delta psi) were imposed on the vesicles...... indicates that NH4+ and MA compete for the same uptake mechanism. The observed fluxes suggest that voltage-driven channels are operating in the wsymbiosome membrane and that these are capable of transporting NH4+ at high rates from the bacteroid side of the membrane to the plant cytosol. The p...

  14. Hybrid Perovskite, CH3NH3PbI3, for Solar Applications: An Experimental and Theoretical Analysis of Substitution in A and B Sites

    Directory of Open Access Journals (Sweden)

    Antonio Sánchez-Coronilla


    Full Text Available The effect of the incorporation of NH4+ into the CH3NH3+ sites of the tetragonal perovskite CH3NH3PbI3 is analysed. Also, how it affects the introduction of Cd2+ cations into Pb2+ sites for a perovskite with 25 at.% of NH4+ is addressed. The incorporation of NH4+ into perovskite leads to a dramatic loss of crystallinity and to the presence of other phases. Moreover, the NH4PbI3 was not found. The less formation of perovskite when NH4+ is incorporated is due to geometrical factors and not changes in the chemical state bonding of the ions. Also, the samples where perovskite is formed show similar band gap values. A slight increase is observed for samples with x=0.5 and 0.75. For the sample with x=1, a drastic increase of the band gap is obtained. Periodic-DFT calculations agree with the experimental structural tendency when NH4+ is incorporated and the density of states analysis confirmed the experimental band gap. The perovskite with 25 at.% of NH4+ was selected for studying the effect of the concentration of Cd on the structural and electronic properties. The theoretical band gap values decreased with the Cd concentration where the narrowing of Cd s-states in the conduction band plays an important role.

  15. Synthesis, crystal structures and characterization of two novel organic-inorganic hybrid compounds (C5NH6)6Bi4Br18 and [C(NH2)3]3BiI6 (United States)

    Li, S. G.; Chen, L.; Xiang, Y.


    Two novel organic-inorganic compounds (C5NH6)6Bi4Br18 (1) and [C(NH2)3]3BiI6 (2) have been synthesized and characterized by elemental analysis, measured by DSC and single-crystal X-ray diffraction at room temperature. The crystal structure of (1) crystallizes in the monoclinic space group C2/m, with a = 17.12 (3), b = 15.3939 (1), c = 13.412 (2) Å, β = 123.702 (7)°, V = 3042.2 (8) Å3 and Z = 2. The crystal structure consists of discrete quad-core [Bi4Br18]6- anions and [C5NH6]+ cations. 2 crystallizes in triclinic space group P-1, with the following unit cell parameters: a = 9.3435 (2), b = 15.583 (4), c = 17.200 (4) Å, α = 86.383 (1), β = 75.689 (1), γ = 89.918 (6)°, V = 2421.5 (10) Å3 and Z = 4. The crystal lattice is composed of discrete [BiI6]3- anions surrounded by [C(NH2)3]+ cations. The DSC experiment of 1 clearly displays that a phase transition occurred at 124.7 K, while 2 undergoes a phase transition at 192.5 K.


    Institute of Scientific and Technical Information of China (English)

    陈砺; 谭盈科


    A study on the adsorption characteristics of the chemisorptionrefrigeration working pair using SrCl2 as adsorbent and NH3 as refrigerant was performed.The adsorption isotherms were obtained,the adsorpt i on isotherm equations were fit and the chemisorption mechanisms were discussed.T he results showed that SrCl2-NH3 is an excellent working pair in its larg e adsorption refrigeration capacity per unit weight of adsorbent and suitable fo r solar energy and low grade waste heat.%对以SrCl2为吸附剂、NH3为致冷剂所组成的化学吸附式制冷工质对的吸附性能进行了研究,得到了吸附等温线、回归出吸附等温方程并对化学吸附过程机理进行了探讨。研究结果表明,SrCl2-NH3工质对的吸附制冷量大,适宜太阳能或低品位余热驱动,是性能优良的工质对。

  17. Studies on the dyeing behaviour of reactive dyes on oxidized linen grafted with HBP-NH2%HBP-NH2接枝氧化亚麻织物活性染料染色性能研究

    Institute of Scientific and Technical Information of China (English)

    赵兵; 张峰; 林红; 陈宇岳


    用端氨基超支化合物(HBP-NH2)对选择性氧化后的亚麻织物进行接枝,再经活性染料染色.探讨了端氨基超支化合物(HBP-NH9接枝氧化亚麻织物工艺中的氧化时间、HBP-NH2溶液质量浓度、pH值、温度、时间对亚麻织物活性染料无盐染色性能的影响结果表明:6 g/L高碘酸钠40℃氧化10 min,HBP-NH2质量浓度5 g/L,pH值9,80℃接枝反应10 min时,采用活性染料无盐染色可取得令人满意的效果.

  18. Jet-Cooled Infrared Laser Spectroscopy in the Umbrella νb{2} Vibration Region of NH_3: Improving the Potential Energy Surface Model of the NH_3-Ar Van Der Waals Complex (United States)

    Asselin, Pierre; Jabri, Atef; Potapov, Alexey; Loreau, Jérome; van der Avoird, Ad


    Taking advantage of our sensitive laser spectrometer coupled to a pulsed slit jet, we recorded near the νb{2} vibration a series of rovibrational transitions of the NH_3-Ar van der Waals (vdW) complex. These transitions involve in the ground vibrational state several internal rotor states corresponding to the ortho{NH_3} and para{NH_3} spin modifications of the complex. They are labeled by Σ_{a}(j,k), Σ_{s}(j,k), Π_{a}(j,k) and Π_{s}(j,k) where Σ(K=0) and Π(K=1) indicate the projection K of the total rotational angular momentum J on the vdW axis, the superscripts s and a designate a symmetric or antisymmetric NH_3 inversion wave function, and j, k quantum numbers indicate the correlation between the internal-rotor state of the complex and the j, k rotational state of the free NH_3 monomer. Five bands have been identified, only one of which was partly observed before. They include transitions starting from the Σ_{a}(j=0 or j=1) state without any internal angular momentum, consequently they can be assigned from the band contour of a linear-molecule-like K=0, ΔJ=1 transition. The energies and splittings of the rovibrational levels of the νb{2}=1←0 spectrum derived from the analysis of the Π_{s}, Σ_{s}(j=1)← Σ_{a}(j=0), k=0 bands and mostly of the Σ_{s}, Π_{s} and Σ_{a}(j=1)←Σ_{a}(j=1), k=1 bands bring relevant information about the νb{2} dependence of the NH_3-Ar interaction, the rovibrational dynamics of the NH_3-Ar complex and provide a sensitive test of a recently developed 4D potential energy surface that includes explicitly its dependence on the umbrella motion. P. Asselin, Y. Berger, T. R. Huet, R. Motiyenko, L. Margulès, R. J. Hendricks, M. R. Tarbutt, S. Tokunaga, B. Darquié, PCCP 19, 4576 (2017), G. T. Fraser, A.S. Pine and W. A. Kreiner, J. Chem. Phys. 94, 7061 (1991). J. Loreau, J. Liévin, Y. Scribano and A. van der Avoird, J. Chem. Phys. 141, 224303 (2014).

  19. Theoretical studies of electrostatic Stark deceleration for subsonic NH3 molecular b eams%亚声速NH3分子束静电Stark减速的理论研究∗

    Institute of Scientific and Technical Information of China (English)


    In this paper, we investigate theoretically the Stark deceleration and cooling of subsonic NH3 molecular beams based on our second-generation electrostatic Stark decelerator with 180 stages. Firstly, we calculate the Stark shifts of NH3 molecules in the|J =1, K =1⟩states and show the stable area of longitudinal phase space for different synchronous phase angles. Secondly, we study the slowing performance of NH3 molecular beams in the traditional mode, and discuss the relationships between various parameters (such as the kinetic energy loss per stage, final velocity and the slowing efficiency) and the synchronous phase angle ϕ0, as well as the dependence of final velocity on the applied voltages. It is found that a subsonic NH3 molecular beam can be decelerated from 280 to 6.7 m/s at ϕ0 = 26.08◦ when the high voltages applied on the electrodes are ±13 kV, corresponding to a removal of 99.9% kinetic energy. The translational temperature of the molecular packets in the moving frame is significantly reduced from 1.34 K to 80 mK. Finally, we study the slowing performance of NH3 molecules and the dependence of final velocity on the synchronous phase angle in an alternate operation mode. In this mode, a synchronous phase angleϕ0=0◦is chosen to bunch the molecules by using the first 15 stages. The remaining 165 stages are then used to slow a subsonic molecular beam at a certain synchronous phase angle. Our result shows that a molecular beam with a mean velocity of 280 m/s can be decelerated to 20.7 m/s at ϕ0 =65.4◦ when the voltages applied are ±6.5 kV, indicating a 99.4% kinetic energy removal, and the translational temperature of the molecular packets can be reduced from 1.34 K to 1.6 mK. By comparing the results obtained from the two operational modes, the temperature of the slowed molecular packet in the alternate mode is 50 times lower than that in the traditional mode. It is shown that our second-generation 180-stage Stark decelerator can effectively

  20. Theoretical study on the reaction between NH3 and MgH2%NH3与MgH2反应机理的密度泛函理论研究

    Institute of Scientific and Technical Information of China (English)



    The reaction mechanism between NH3 and MgH2 has been investigated by a B3LYP method of density functional theory, and the geometries and harmonic vibration frequencies of reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311G( d,p) level. Vibration analysis and intrinsic reaction coordinates ( IRC) calculation at the same level have been applied to validate the connection of the sta-tionary points. The results indicate that the reaction between NH3 and MgH2 has two single-channel hydrogen substitution reactions, the reaction products are Mg(NH2)2 and H2. The two released hydrogen atoms in H2 come from NH3 and MgH2 , respectively. The sticking point of the dehydrogenation is overcome to break the bond of N-H.%采用密度泛函理论B3LYP方法研究了NH3与MgH2的放氢反应机理,在6-311G(d, p)基组水平上对反应物、中间体、过渡态及产物进行了全几何参数优化.频率分析和内禀反应坐标( IRC)计算证实了中间体和过渡态的正确性和相互连接关系.计算结果表明:反应分两步单通道的氢取代过程,且反应过程相类似,反应生成Mg(NH2)2和2H2.两步氢取代反应所释放的H2中两个H原子分别来源于NH3和MgH2.反应脱氢的关键在于克服N—H键断裂所需能量.