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Sample records for complexes c9h72lnmu-cl2liet2o2 ln

  1. Rhombus-shaped tetranuclear [Ln4] complexes [Ln = Dy(III) and Ho(III)]: synthesis, structure, and SMM behavior.

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    Chandrasekhar, Vadapalli; Hossain, Sakiat; Das, Sourav; Biswas, Sourav; Sutter, Jean-Pascal

    2013-06-03

    The reaction of a new hexadentate Schiff base hydrazide ligand (LH3) with rare earth(III) chloride salts in the presence of triethylamine as the base afforded two planar tetranuclear neutral complexes: [{(LH)2Dy4}(μ2-O)4](H2O)8·2CH3OH·8H2O (1) and [{(LH)2Ho4}(μ2-O)4](H2O)8·6CH3OH·4H2O (2). These neutral complexes possess a structure in which all of the lanthanide ions and the donor atoms of the ligand remain in a perfect plane. Each doubly deprotonated ligand holds two Ln(III) ions in its two distinct chelating coordination pockets to form [LH(Ln)2](4+) units. Two such units are connected by four [μ2-O](2-) ligands to form a planar tetranuclear assembly with an Ln(III)4 core that possesses a rhombus-shaped structure. Detailed static and dynamic magnetic analysis of 1 and 2 revealed single-molecule magnet (SMM) behavior for complex 1. A peculiar feature of the χM" versus temperature curve is that two peaks that are frequency-dependent are revealed, indicating the occurrence of two relaxation processes that lead to two energy barriers (16.8 and 54.2 K) and time constants (τ0 = 1.4 × 10(-6) s, τ0 = 7.2 × 10(-7) s). This was related to the presence of two distinct geometrical sites for Dy(III) in complex 1.

  2. Synthesis and magnetochemistry of heterometallic triangular FeLn(III) (Ln = La, Gd, Tb, Dy, and Ho) and FeY(III) complexes.

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    Singh, Namrata; Das Gupta, Sayak; Butcher, Raymond J; Christou, George

    2017-06-20

    A series of Fe2Ln (Ln = La, Gd, Tb, Dy and Ho) and Fe2Y complexes have been synthesized via metal substitution and characterized by single crystal X-ray diffraction. All the molecules are isostructural and have a Fe2LnO triangular core with the oxygen atom existing as an μ3-oxo(2-) anion. DC and AC magnetic susceptibility studies were performed on all the molecules. For Fe2Ln (Ln = Gd, La) and Fe2Y, the data were fitted to Van Vleck equations and the magnetic coupling constants were obtained. In all cases, the two Fe(iii) spins were found to be antiparallel to each other in the ground state leaving the heterometal to remain essentially uncoupled.

  3. Distinct reaction pathways of peralkylated LnIIAlIII heterobimetallic complexes with substituted phenols.

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    Sommerfeldt, Hanne-Marthe; Meermann, Christian; Törnroos, Karl W; Anwander, Reiner

    2008-06-02

    The protonolysis reaction of heterobimetallic peralkylated complexes [Ln(AlR4)2]n (Ln=Sm, Yb; R=Me, Et) with 2 equiv of HOC 6H 2 tBu 2-2,6-Me-4 affords the bis(trialkylaluminum) adducts Ln[(micro-OArtBu,Me)(micro-R)AlR2]2 in good yields. Analogous reactions with the less sterically demanding iPr-substituted phenol result in ligand redistributions and formation of X-ray structurally evidenced Ln[(micro-OAriPr,H) 2AlR2]2 (Ln=Yb, R=Me; Ln=Sm, R=Et), Yb[(micro-OAriPr,H)(micro-Et)AlEt2]2(THF), and [Et2Al(micro-OAriPr,H) 2Yb(micro-Et)2AlEt2]2. The solid-state structures of serendipitous alumoxane complex Sm[(micro-OArtBu,Me)AlEt2OAlEt2(micro-OArtBu,Me)](toluene) and dimeric AlMe 3-adduct complex [(AlMe3)(micro-OArtBu,Me)Sm(micro-OArtBu,Me) 2Sm(micro-OArtBu,Me)(AlMe3)] were also determined by X-ray crystallography. While the former can be discussed as a typical hydrolysis product of Sm[(micro-OArtBu,Me)(micro-Et)AlEt2]2, the latter was isolated from the 1:1 reaction of [Sm(AlEt4)2]n with HOArtBu,Me.

  4. Ln(iii) complexes (Ln = Eu, Gd, Tb, Dy) with a chiral ligand containing 1,10-phenanthroline and (-)-menthol fragments: synthesis, structure, magnetic properties and photoluminescence.

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    Larionov, Stanislav V; Bryleva, Yuliya A; Glinskaya, Ludmila A; Plyusnin, Victor F; Kupryakov, Arkady S; Agafontsev, Alexander M; Tkachev, Alexey V; Bogomyakov, Artem S; Piryazev, Dmitry A; Korolkov, Ilya V

    2017-08-29

    A series of lanthanide(iii) complexes based on the new chiral ligand L, which contains 1,10-phenanthroline and (-)-menthol fragments, namely [LnL2(NO3)3] (Ln = Eu (1), Gd (2), Tb (3), Dy (4)), have been synthesized and structurally characterized. Complexes 1-4 are isostructural and crystallize in the non-centrosymmetric space group P41212. The mononuclear complexes comprise a 10-coordinate Ln3+ ion with two bidentate N,N-donor ligands (L) and three bidentate chelating nitrate groups. The magnetic properties of complexes 1-4 are determined mainly by the Ln3+ ions. In the case of complexes 3 and 4, significant anisotropy results in nonlinear field dependences of magnetization at low temperature. Complexes 1, 3 and 4 exhibit metal-centered red (Eu3+), green (Tb3+) and yellow (Dy3+) luminescence, respectively, whereas complex 2 displays blue ligand-based luminescence in the solid state at room temperature. The luminescence quantum yield for the solid samples increases in the order 4 < 2 ≈ 3 < 1. The europium(iii) complex shows long luminescence lifetimes (up to 1750 μs) and a very high quantum yield (φf = 0.87); these make this compound promising for application in sensing and optoelectronics.

  5. Six-Coordinate Ln(III Complexes with Various Coordination Geometries Showing Distinct Magnetic Properties

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    Mei Guo

    2018-01-01

    Full Text Available The syntheses, structural characterization, and magnetic properties of three lanthanide complexes with formulas [Ln(L13] (Ln = Dy (1Dy; Er (1Er; and [Dy(L22] (2Dy were reported. Complexes 1Dy and 1Er are isostructural with the metal ion in distorted trigonal-prismatic coordination geometry, but exhibit distinct magnetic properties due to the different shapes of electron density for DyIII (oblate and ErIII (prolate ions. Complex 1Dy shows obvious SMM behavior under a zero direct current (dc field with an effective energy barrier of 31.4 K, while complex 1Er only features SMM behavior under a 400 Oe external field with an effective energy barrier of 23.96 K. In stark contrast, complex 2Dy with the octahedral geometry only exhibits the frequency dependence of alternating current (ac susceptibility signals without χ″ peaks under a zero dc field.

  6. SPECTROSCOPIC PROPERTIES OF THE Ln-Ge COMPLEXES WITH DIETHYLENETRIAMINEPENTAACETIC ACID

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    Sergiy Smola

    2007-06-01

    Full Text Available Four new heteronuclear lanthanide complexes with general formula [Ge(OH(μ-HDTPALnGe(OH (μ-DTPA] (Ln = Sm – Dy were synthesized and subsequently characterized by different physico- chemical methods. The structures of new compounds have been proposed. In considered complexes the 4f-luminescence of three-charged ions of samarium, europium, terbium and dysprosium is realized at UV-excitation. It is noteworthy that it is the first observation of 4f-luminescence in water solutions of heteronuclear f-p-complexes. The comparison of luminescent characteristics of hetero- and homonuclear landthanide complexes is described and discussed as well.

  7. Thiacalix[4]arene-supported kite-like heterometallic tetranuclear Zn(II)Ln(III)3 (Ln = Gd, Tb, Dy, Ho) complexes.

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    Su, Kongzhao; Jiang, Feilong; Qian, Jinjie; Wu, Mingyan; Xiong, Kecai; Gai, Yanli; Hong, Maochun

    2013-04-01

    Four kite-like tetranuclear Zn(II)Ln(III)3 (Ln= Gd 1, Tb 2, Dy 3, Ho 4) clusters supported by p-tert-butylthiacalix[4]arene (H4BTC4A) have been prepared under solvothermal conditions and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction (PXRD). In the structures of these four complexes, each of them is capped by two tail-to-tail p-tert-butylthiacalix[4]arene molecules to form a bent sandwich-like unit. The photoluminescent analyses reveal that the H4BTC4A is an efficient sensitizer for Tb(3+) ions in 2. The magnetic properties of complexes 1-4 are also investigated, in which complex 3 exhibits slow magnetization relaxation typical for single molecule magnets.

  8. Characterization and reactivity of peralkylated LnIIAlIII heterobimetallic complexes.

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    Sommerfeldt, Hanne-Marthe; Meermann, Christian; Schrems, Marcus G; Törnroos, Karl W; Frøystein, Nils Age; Miller, Robert J; Scheidt, Ernst-Wilhelm; Scherer, Wolfgang; Anwander, Reiner

    2008-04-14

    The heterobimetallic peralkylated complexes [Ln(AlR4)2]n (Ln = Sm, Yb; R = Me, Et) were synthesized by a silylamide elimination route from Ln[N(SiMe3)2]2(THF)2 and an excess of AlR3. The solid-state structure of [Sm(AlEt4)2]n is isomorphous to that of the ytterbium derivative. Polymeric [Yb(AlMe4)2]n was examined by 1H and 13C MAS NMR spectroscopy revealing the presence of distinct bridging methyl groups. The reaction of [Yb(AlMe4)2]n and 1,10-phenanthroline (Phen) afforded the monomeric donor adduct Yb(AlMe4)2(Phen), while the protonolysis reaction with 2 equiv. C5Me5H (HCp*) yielded a separated ion pair of composition [Cp*Yb(THF)(4)][AlMe(4)]. Single-crystal X-ray diffraction data are provided for both ytterbium(II) complexes. Solid-state magnetic measurements (SQUID) were performed on [Sm(AlMe4)2]n, [Sm(AlEt4)2]n, SmI2(THF)2 and Sm[N(SiMe3)2]2(THF)2 showing high effective magnetic moments 3.67micro(B) < micro(eff) < 4.43micro(B).

  9. Exploring the Influence of Diamagnetic Ions on the Mechanism of Magnetization Relaxation in {CoIII2LnIII2} (Ln = Dy, Tb, Ho) "Butterfly" Complexes.

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    Vignesh, Kuduva R; Langley, Stuart K; Murray, Keith S; Rajaraman, Gopalan

    2017-03-06

    The synthesis and magnetic and theoretical studies of three isostructural heterometallic [CoIII2LnIII2(μ3-OH)2(o-tol)4(mdea)2(NO3)2] (Ln = Dy (1), Tb (2), Ho (3)) "butterfly" complexes are reported (o-tol = o-toluate, (mdea)2- = doubly deprotonated N-methyldiethanolamine). The CoIII ions are diamagnetic in these complexes. Analysis of the dc magnetic susceptibility measurements reveal antiferromagnetic exchange coupling between the two LnIII ions for all three complexes. ac magnetic susceptibility measurements reveal single-molecule magnet (SMM) behavior for complex 1, in the absence of an external magnetic field, with an anisotropy barrier Ueff of 81.2 cm-1, while complexes 2 and 3 exhibit field induced SMM behavior, with a Ueff value of 34.2 cm-1 for 2. The barrier height for 3 could not be quantified. To understand the experimental observations, we performed DFT and ab initio CASSCF+RASSI-SO calculations to probe the single-ion properties and the nature and magnitude of the LnIII-LnIII magnetic coupling and to develop an understanding of the role the diamagnetic CoIII ion plays in the magnetization relaxation. The calculations were able to rationalize the experimental relaxation data for all complexes and strongly suggest that the CoIII ion is integral to the observation of SMM behavior in these systems. Thus, we explored further the effect that the diamagnetic CoIII ions have on the magnetization blocking of 1. We did this by modeling a dinuclear {DyIII2} complex (1a), with the removal of the diamagnetic ions, and three complexes of the types {KI2DyIII2} (1b), {ZnII2DyIII2} (1c), and {TiIV2DyIII2} (1d), each containing a different diamagnetic ion. We found that the presence of the diamagnetic ions results in larger negative charges on the bridging hydroxides (1b > 1c > 1 > 1d), in comparison to 1a (no diamagnetic ion), which reduces quantum tunneling of magnetization effects, allowing for more desirable SMM characteristics. The results indicate very strong

  10. Spectroscopic properties and electronic-optic parameters of complexes Ln(NO{sub 3}){sub 3}.2DTPO.4H{sub 2}O (Ln = Nd and Er); Propriedades espectroscopicas e parametros opticos-eletronicos dos complexos Ln(NO{sub 3}){sub 3}.2DTPO.4H{sub 2}O (Ln = Nd e Er)

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    Pedrosa, Anne M. Garrido; Pimentel, Patricia M.; Batista, Mary K.S.; Lima, Francisco J.S.; Melo, Dulce M.A. [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Quimica]. E-mail: limafjs@yahoo.com

    2004-06-01

    Complexes with the composition Ln(NO{sub 3}){sub 3}.2DTPO.4H{sub 2}O (Ln = Nd and Er) were synthesized and characterized by infrared and visible absorption spectra (solid state and solution). The results of the absorption spectra in the solid state suggest that metal-ligand bonds are essentially electrostatic in all complexes. The absorption spectra of the nitrate salt solution presented smaller values of the oscillator strength when compared to the spectra of the complexes in the same solvent. (author)

  11. Propriedades espectroscópicas e parâmetros ópticos-eletrônicos dos complexos Ln(NO33.2DTPO.4H2O (Ln = Nd e Er Spectroscopic properties and electronic-optic parameters of complexes Ln(NO33.2DTPO.4H2O (Ln = Nd and Er

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    Anne M. Garrido Pedrosa

    2004-06-01

    Full Text Available Complexes with the composition Ln(NO33.2DTPO.4H2O (Ln = Nd and Er were synthesized and characterized by infrared and visible absorption spectra (solid state and solution. The results of the absorption spectra in the solid state suggest that metal-ligand bonds are essentially electrostatic in all complexes. The absorption spectra of the nitrate salt solution presented smaller values of the oscillator strength when compared to the spectra of the complexes in the same solvent.

  12. Effect of the ion force on the stability constants of the complexes LnCl{sup 2+} and LnCl{sub 2}{sup +} of Europium and Lutetium; Efecto de la fuerza ionica sobre las constantes de estabilidad de los complejos LnCl{sup 2+} y LnCl{sub 2}{sup +} de Europium y Lutetium

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    Fernandez R, E.; Jimenez R, M.; Solache R, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    A study is presented on the determination of the constants of stability of those complex LnCI{sup 3-n}{sub n} (where Ln = Eu{sup 3+} and Lu{sup 3+} and n = 1 and 2), by means of a method of extraction with solvent, to constant temperature (303 K) and in means of high ionic force (1- 3M H CI/HCIO{sub 4}). It is also presented the application of the theory of the specific interaction of ions (SIT) of Bronsted-Guggenheim-Scatchard for the extrapolation of the values to infinite dilution. (Author)

  13. S-shaped decanuclear heterometallic [Ni8Ln2] complexes [Ln(III) = Gd, Tb, Dy and Ho]: theoretical modeling of the magnetic properties of the gadolinium analogue.

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    Hossain, Sakiat; Das, Sourav; Chakraborty, Amit; Lloret, Francesc; Cano, Joan; Pardo, Emilio; Chandrasekhar, Vadapalli

    2014-07-14

    The reaction of 8-quinolinol-2-carboaldoxime (LH2) with Ni(II) and Ln(III) salts afforded the heterometallic decanuclear compounds [Ni8Dy2(μ3-OH)2(L)8(LH)2(H2O)6](ClO4)2·16H2O (1), [Ni8Gd2(μ3-OH)2(L)8(LH)2(H2O)4(MeOH)2](NO3)2·12H2O (2), [Ni8Ho2(μ3-OH)2(L)8(LH)2(H2O)4(MeOH)2](ClO4)2·2MeOH·12H2O (3) and [Ni8Tb2 (μ3-OH)2(L)8(LH)2(MeOH)4(OMe)2]·2CH2Cl2·8H2O (4). While compounds 1-3 are dicationic, compound 4 is neutral. These compounds possess an S-shaped architecture and comprise a long chain of metal ions bound to each other. In all the complexes, the eight Ni(II) and two Ln(III) ions of the multimetallic ensemble are hold together by two μ3-OH, eight dianionic (L(2-)) and two monoanionic oxime ligands (LH(-)) whereas compound 4 has two μ3-OH, eight dianionic (L(2-)), two monoanionic oxime ligands (LH(-)) and two terminal methoxy (MeO(-)) ligands. The central portion of the S-shaped molecular wire is made up of an octanuclear Ni(II) ensemble which has at its two ends the Ln(III) caps. Magnetic studies on 1-4 reveal that the magnetic interactions between neighboring metal ions are negligible at room temperature. On the other hand, at lower temperatures in all the compounds anti-ferromagnetic interactions seem to be dominated. Analysis of the magnetic data for the Gd(III) derivative indicates Ni(II)-Ni(II) anti-ferromagnetic interactions and Gd(III)-Ni(II) ferromagnetic interactions at low temperatures. A theoretical density functional study on the magnetic behavior of the Gd(III) derivative suggests that while the weak ferromagnetic interaction between Gd(III) and Ni(II) is in line with the expectation of the magnetic interactions between orthogonal d and f orbitals, antiferromagnetic Ni(II)-Ni(II) interactions are related to the wide Ni-O-Ni angles (∼102°) and quasi-planar conformation of the Ni2O2 core.

  14. Synthesis and Structures of Two Lanthanide Complexes Containing a Mixed Ligand System: [Ln(Phen){sub 2}(L){sub 3}(HL)]·H{sub 2}O [Ln = La, Ce; Phen = Phenanthroline; HL = Salicylic Acid

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    Iravani, Effat [UNiv. of Applied Science and Technology, Tehran (Iran, Islamic Republic of); Nami, Navabeh; Nabizadeh, Fatemeh; Bayani, Elham [Islamic Azad Univ., Mazandaran (Iran, Islamic Republic of); Neumueller, Bernhard [Philipps-Universitat Marburg, Marburg (Germany)

    2013-11-15

    The reaction of LnCl{sub 3}·7H{sub 2}O [Ln = La (1), Ce (2)] with salicylic acid (HL) and 1,10-phenanthroline (Phen) at 20 .deg. C in H{sub 2}O/ethanol gave after work-up and recrystallization two novel lanthanide complexes with general formula [Ln(Phen){sub 2}(L){sub 3}(HL)]·H{sub 2}O. Compounds 1 and 2 were characterized by IR and UV-Vis spectroscopy, TGA, CHN as well as by X-ray analysis. According to these results, compounds 1 and 2 are isostructural and contain Ln{sup 3+} ions with coordination number nine. Complexes 1 and 2 consist of two Phen, one neutral HL and three L anions (two L anions act as monodentate ligands and the third one is chelating to Ln{sup 3+}). Thermal decomposition led to primary loss of the Phen molecules. Then HL molecules and finally L moieties left the material to give Ln{sub 2}O{sub 3}.

  15. Family of defect-dicubane Ni4Ln2 (Ln = Gd, Tb, Dy, Ho) and Ni4Y2 complexes: rare Tb(III) and Ho(III) examples showing SMM behavior.

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    Zhao, Lang; Wu, Jianfeng; Ke, Hongshan; Tang, Jinkui

    2014-04-07

    Reactions of Ln(III) perchlorate (Ln = Gd, Tb, Dy, and Ho), NiCl2·6H2O, and a polydentate Schiff base resulted in the assembly of novel isostructural hexanuclear Ni4Ln2 complexes [Ln = Gd (1), Tb (2), Dy (3), Ho (4)] with an unprecedented 3d-4f metal topology consisting of two defect-dicubane units. The corresponding Ni4Y2 (5) complex containing diamagnetic Y(III) atoms was also isolated to assist the magnetic studies. Interestingly, complexes 2 and 3 exhibit SMM characteristics and 4 shows slow relaxation of the magnetization. The absence of frequency-dependent in-phase and out-of-phase signals for the Ni-Y species suggests that the Ln ions' contribution to the slow relaxation must be effectual as previously observed in other Ni-Dy samples. However, the observation of χ″ signals with zero dc field for the Ni-Tb and Ni-Ho derivatives is notable. Indeed, this is the first time that such a behavior is observed in the Ni-Tb and Ni-Ho complexes.

  16. Family of carboxylate- and nitrate-diphenoxo triply bridged dinuclear Ni(II)Ln(III) complexes (Ln = Eu, Gd, Tb, Ho, Er, Y): synthesis, experimental and theoretical magneto-structural studies, and single-molecule magnet behavior.

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    Colacio, Enrique; Ruiz, José; Mota, Antonio J; Palacios, María A; Cremades, Eduard; Ruiz, Eliseo; White, Fraser J; Brechin, Euan K

    2012-05-21

    Seven acetate-diphenoxo triply bridged M(II)-Ln(III) complexes (M(II) = Ni(II) and Ln(III) = Gd, Tb, Ho, Er, and Y; M(II) = Zn(II) and Ln(III) = Ho(III) and Er(III)) of formula [M(μ-L)(μ-OAc)Ln(NO(3))(2)], one nitrate-diphenoxo triply bridged Ni(II)-Tb(III) complex, [Ni(μ-L)(μ-NO(3))Tb(NO(3))(2)]·2CH(3)OH, and two diphenoxo doubly bridged Ni(II)-Ln(III) complexes (Ln(III) = Eu, Gd) of formula [Ni(H(2)O)(μ-L)Ln(NO(3))(3)]·2CH(3)OH have been prepared in one pot reaction from the compartmental ligand N,N',N"-trimethyl-N,N"-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (H(2)L). Moreover, Ni(II)-Ln(III) complexes bearing benzoate or 9-anthracenecarboxylate bridging groups of formula [Ni(μ-L)(μ-BzO)Dy(NO(3))(2)] and [Ni(μ-L)(μ-9-An)Dy(9-An)(NO(3))(2)]·3CH(3)CN have also been successfully synthesized. In acetate-diphenoxo triply bridged complexes, the acetate bridging group forces the structure to be folded with an average hinge angle in the M(μ-O(2))Ln bridging fragment of ~22°, whereas nitrate-diphenoxo doubly bridged complexes and diphenoxo-doubly bridged complexes exhibit more planar structures with hinge angles of ~13° and ~2°, respectively. All Ni(II)-Ln(III) complexes exhibit ferromagnetic interactions between Ni(II) and Ln(III) ions and, in the case of the Gd(III) complexes, the J(NiGd) coupling increases weakly but significantly with the planarity of the M-(O)(2)-Gd bridging fragment and with the increase of the Ni-O-Gd angle. Density functional theory (DFT) theoretical calculations on the Ni(II)Gd(III) complexes and model compounds support these magneto-structural correlations as well as the experimental J(NiGd) values, which were found to be ~1.38 and ~2.1 cm(-1) for the folded [Ni(μ-L)(μ-OAc)Gd(NO(3))(2)] and planar [Ni(H(2)O)(μ-L)Gd(NO(3))(3)]·2CH(3)OH complexes, respectively. The Ni(II)Dy(III) complexes exhibit slow relaxation of the magnetization with Δ/k(B) energy barriers under 1000 Oe applied magnetic fields of 9.2 and 10

  17. Structural and spectroscopic studies of [bis(picrato)(pentaethylene glycol)lanthanide(III)] picrate complexes with Ln(III) = Sm, Dy and Ho

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    Saleh, Muhammad I.; Kusrini, Eny; Adnan, Rohana; Saad, Bahruddin; Yamin, Bohari M.; Fun, Hoong K.

    2007-06-01

    The Sm(III), Dy(III) and Ho(III) complexes with mixed pentaethylene glycol (EO5) and picrate (Pic -) ligands were obtained and characterized by elemental analysis, IR, 1H and 13C NMR spectroscopic techniques. They are isostructural with general formula of [Ln(Pic) 2(EO5)] +(Pic) - (Ln = Sm(III), Dy(III) and Ho(III)). X-ray investigations showed that all the three complexes consist of hexadentate EO5 ligand and two picrate anions, one chelated in bidentate manner and the other one is monodentate located on the opposite sides of the primary Ln1-EO5 coordination sphere in a nine coordination environment. The geometry of the Ln1-EO5 sphere is tricapped trigonal prismatic with both benzene rings almost vertical to each other. TGA spectra of the complexes showed a gradual decomposition started from 250 °C followed by a sharp decrease in weight loss at 265 °C.

  18. Correlation between slow magnetic relaxation and the coordination structures of a family of linear trinuclear Zn(II)-Ln(III)-Zn(II) complexes (Ln = Tb, Dy, Ho, Er, Tm and Yb).

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    Maeda, Moe; Hino, Shiori; Yamashita, Kei; Kataoka, Yumiko; Nakano, Motohiro; Yamamura, Tomoo; Kajiwara, Takashi

    2012-11-28

    Six linear trinuclear [Ln{Zn(L)(AcO)}(2)]BPh(4) complexes (H(2)L denotes the Schiff-base ligand formed by a condensation reaction between ethylenediamine and two equivalents of o-vanillin), including Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5) and Yb (6) were synthesized and were confirmed to be isostructural via X-ray crystallographic analyses. The Ln(III) ion in each complex is deca-coordinated by four equatorial oxygen donors from the methoxo groups of the Schiff-base ligands, two oxygen donors from the acetate anions and four axial oxygen donors from the phenoxo groups of the Schiff-base ligands. AC susceptibility measurements, with an oscillating frequency of 10 to 10,000 Hz, revealed that 1, 2, 4 and 6 show slow magnetic relaxation under a 1000 Oe DC bias field, which occurs via a single process, as confirmed by the semi-circular Cole-Cole plots. These complexes are considered to be field-induced single-molecule magnets under these conditions. The presence or absence of the slow magnetic relaxation process is discussed by correlating the characteristic magnetic anisotropy of each Ln(III) ion with the ligand field anisotropy.

  19. Heterometallic trinuclear {CoLn(III)} (Ln = Gd, Tb, Ho and Er) complexes in a bent geometry. Field-induced single-ion magnetic behavior of the Er(III) and Tb(III) analogues.

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    Goura, Joydeb; Brambleby, Jamie; Topping, Craig V; Goddard, Paul A; Suriya Narayanan, Ramakirushnan; Bar, Arun Kumar; Chandrasekhar, Vadapalli

    2016-05-31

    Through the use of a multi-site compartmental ligand, 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl]phenol (LH3), the family of heterometallic, trinuclear complexes of the formula [CoLn(L)2(μ-O2CCH3)2(H2O)3]·NO3·xMeOH·yH2O has been expanded beyond Ln = Dy(III) to include Gd(III) (), Tb(III) (), Ho(III) () and Er(III) () for , and (x = 1; y = 1) and for (x = 0; y = 2). The metallic core of these complexes consists of a (Co(III)-Ln(III)-Co(III)) motif bridged in a bent geometry resulting in six-coordinated distorted Co(III) octahedra and nine-coordinated Ln(III) monocapped square-antiprisms. The magnetic characterization of these compounds reveals the erbium and terbium analogues to display a field induced single-ion magnetic behavior similar to the dysprosium analogue but at lower temperatures. The energy barrier for the reversal of the magnetization of the CoTb(III) analogue is Ueff ≥ 15.6(4) K, while for the CoEr(III) analogue Ueff ≥ 9.9(8) K. The magnetic properties are discussed in terms of distortions of the 4f electron cloud.

  20. Ferrocene-based compartmental ligand for the assembly of neutral Zn(II)/Ln(III) heterometallic complexes.

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    Chandrasekhar, Vadapalli; Chakraborty, Amit; Sañudo, E Carolina

    2013-10-07

    A ferrocene-based compartmental ligand, H2L, was synthesized by the reaction of diacetyl ferrocene with hydrazine hydrate followed by a condensation reaction with o-vanillin. [L](2-) possesses a dual coordination pocket, an inner pocket of 2 imino nitrogens and two phenolate oxygens and an outer pocket of two phenolate and two methoxy oxygen atoms. Utilizing this ligand, several Zn(II)/Ln(III) heterobimetallic complexes were assembled: [LZn(μ-OAc)Dy(NO3)2] (2), [LZn(μ-OAc)Tb(NO3)2] (3), [LZn(μ-OAc)Gd(NO3)2·2CHCl3] (4), [LZn(μ-OAc)Er(NO3)2] (5), [LZn(μ-OAc)Ho(NO3)2] (6), [LZn(μ-OAc)Eu(NO3)2] (7). All of these metal complexes are neutral and isostructural: the Zn(II) ion occupies the inner coordination pocket while the Ln(III) ion occupies the outer coordination pocket of the doubly deprotonated ligand [L](2-). Zn(II) has a coordination number of 5 (2N, 3O) in a square pyramidal coordination geometry while Ln(III) has a coordination number of 9 (9O) in a distorted tricapped trigonal prismatic geometry. Zn(II) and the 4f metal ion are bridged to each other by two phenolate oxygen atoms and an acetate ligand. ESI-MS reveals that 2-7 retain their structural integrity in solution. Cyclic voltammetry of 1-7 revealed a quasi-reversible oxidation (involving the ferrocene motif) and an irreversible reduction of the hydrazone unit. Magnetic studies of 2, 3 and 6 were carried out. Ac susceptibility studies did not reveal slow relaxation of magnetization.

  1. Synthesis, crystal structure, and magnetic studies of one-dimensional cyano-bridged Ln3+-Cr3+ complexes with bpy as a blocking ligand.

    Science.gov (United States)

    Estrader, Marta; Ribas, Joan; Tangoulis, Vassilis; Solans, Xavier; Font-Bardía, Merce; Maestro, Miguel; Diaz, Carmen

    2006-10-02

    The reaction of Ln(NO3)3.aq with K3[Cr(CN)6] and 2,2'-bipyridine (bpy) in a water/ethanol solution led to two families of complexes: 4 one-dimensional (1D) complexes of the formula trans-[Cr(CN)4(mu-CN)2Ln(H2O)3(bpy)2]n.4nH2O.3.5nbpy (Ln3+ = La, Ce, Pr, and Nd) and 10 1D complexes of the formula trans-[Cr(CN)4(mu-CN)2Ln(H2O)4(bpy)]n.3.5nH2O.1.5nbpy (Ln3+ = Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The structures for the fourteen complexes [LaCr]n (1), [CeCr]n (2), [PrCr]n (3), [NdCr]n (4), [NdCr]n (4'), [SmCr]n (5), [EuCr]n (6), [TbCr]n (7), [DyCr]n (8), [HoCr]n (9), [ErCr]n (10), [TmCr]n (11), [YbCr]n (12), and [LuCr]n (13) have been solved. Complexes 1-4 crystallize in the orthorhombic space group Pbam and are isomorphous; complexes 4'-13 crystallize in the triclinic space group PI and are isomorphous. The X-ray structural characterization of complexes 1-4 shows the presence of a discrete decameric water cluster built around a cyclic hexameric core stabilized by the solid-state structure, which represents another new mode of association of water molecules. The Ln3+-Cr3+ magnetic interaction is negligible in 6 and 12, antiferromagnetic in 2, 4', 7, 8, 9, 10, and 11, and unresolved for 3. The complex 5 is a ferrimagnet because its magnetic studies suggest the onset of a very weak ferromagnetic three-dimensional ordering.

  2. Ln(III)-malate complexation studies using TRLFS and micro titration calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Taube, F.; Drobot, B. [Technische Univ. Dresden (Germany). Professorship Radiochemistry; Acker, M.; Taut, S. [Technische Univ. Dresden (Germany). Central Radionuclide Laboratory; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    The complexation of trivalent lanthanides was studied using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS) and Isothermal Titration Calorimetry (ITC). Formation constants, complexation enthalpies and fluorescence lifetimes are determined over a wide pH range at I = 0.5 m NaCl. This subject has the following background: Concrete is widely used as engineering barrier and for waste conditioning in waste repositories. Its binding agent is cement. Organic cement additives, which are used to improve the workability of fresh concrete, are complexation agents for radionuclides after they have been released during the concretes degradation. Thus, these additives might have an impact on the aqueous geochemistry of actinides. Here, the α-hydroxydicarboxylic acid or malic acid is examined. It is used in water-reducers or retarders in cement.

  3. Surface-based molecular self-assembly: Langmuir-Blodgett films of amphiphilic Ln(III) complexes.

    Science.gov (United States)

    Wales, Dominic J; Kitchen, Jonathan A

    2016-01-01

    The unique photophysical properties of the Ln(III) series has led to significant research efforts being directed towards their application in sensors. However, for "real-life" applications, these sensors should ideally be immobilised onto surfaces without loss of function. The Langmuir-Blodgett (LB) technique offers a promising method in which to achieve such immobilisation. This mini-review focuses on synthetic strategies for film formation, the effect that film formation has on the physical properties of the Ln(III) amphiphile, and concludes with examples of Ln(III) LB films being used as sensors.

  4. Heterospin systems constructed from [Cu2Ln]3+ and [Ni(mnt)2]1-,2- Tectons: First 3p-3d-4f complexes (mnt = maleonitriledithiolato).

    Science.gov (United States)

    Madalan, Augustin M; Avarvari, Narcis; Fourmigué, Marc; Clérac, Rodolphe; Chibotaru, Liviu F; Clima, Sergiu; Andruh, Marius

    2008-02-04

    New heterospin complexes have been obtained by combining the binuclear complexes [{Cu(H(2)O)L(1)}Ln(O(2)NO)(3)] or [{CuL(2)}Ln(O(2)NO)(3)] (L(1) = N,N'-propylene-di(3-methoxysalicylideneiminato); L(2) = N,N'-ethylene-di(3-methoxysalicylideneiminato); Ln = Gd(3+), Sm(3+), Tb(3+)), with the mononuclear [CuL(1)(2)] and the nickel dithiolene complexes [Ni(mnt)(2)](q)- (q = 1, 2; mnt = maleonitriledithiolate), as follows: (1)infinity[{CuL(1)}(2)Ln(O(2)NO){Ni(mnt)(2)}].Solv.CH(3)CN (Ln = Gd(3+), Solv = CH(3)OH (1), Ln = Sm(3+), Solv = CH(3)CN (2)) and [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)][Ni(mnt)(2)] (3) with [Ni(mnt)2]2-, [{(CH(3)CN)CuL(1)}(2)Ln(H(2)O)][Ni(mnt)(2)]3.2CH(3)CN (Ln = Gd(3+) (4), Sm(3+) (5), Tb(3+) (6)), and [{(CH(3)OH)CuL(2)}{CuL(2)}Gd(O(2)NO){Ni(mnt)(2)}][Ni(mnt)(2)].CH(2)Cl(2) (7) with [Ni(mnt))(2]*-. Trinuclear, almost linear, [CuLnCu] motifs are found in all the compounds. In the isostructural 1 and 2, two trans cyano groups from a [Ni(mnt)2]2- unit bridge two trimetallic nodes through axial coordination to the Cu centers, thus leading to the establishment of infinite chains. 3 is an ionic compound, containing discrete [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)](2+) cations and [Ni(mnt)(2)](2-) anions. Within the series 4-6, layers of discrete [CuLnCu](3+) motifs alternate with stacks of interacting [Ni(mnt)(2)](*-) radical anions, for which two overlap modes, providing two different types of stacks, can be disclosed. The strength of the intermolecular interactions between the open-shell species is estimated through extended Hückel calculations. In compound 7, [Ni(mnt)(2)](*-) radical anions coordinate group one of the Cu centers of a trinuclear [Cu(2)Gd] motif through a CN, while discrete [Ni(mnt)(2)](*-) units are also present, overlapping in between, but also with the coordinated ones. Furthermore, the [Cu(2)Gd] moieties dimerize each other upon linkage by two nitrato groups, both acting as chelate toward the gadolinium ion from one unit and monodentate toward a

  5. Activation of SO2 with [(η(5) -C5 Me5 )2 Ln(THF)2 ] (Ln=Eu, Yb) leading to dithionite and sulfinate complexes.

    Science.gov (United States)

    Klementyeva, Svetlana V; Gamer, Michael T; Schmidt, Anna-Corina; Meyer, Karsten; Konchenko, Sergey N; Roesky, Peter W

    2014-10-13

    The reaction of decamethylytterbocene [(η(5) -C5 Me5 )2 Yb(THF)2 ] with SO2 at low temperature gave two new compounds, namely, the Yb(III) dithionite/sulfinate complex [{(η(5) -C5 Me5 )2 Yb(μ3 ,1κ(2) O(1,3) ,2κ(3) O(2,2',4) -S2 O4 )}2 {(η(5) -C5 Me5 )Yb(μ,1κO,2κO'-C5 Me5 SO2 )}2 ] (1) and the Yb(III) dithionite complex [{(η(5) -C5 Me5 )2 Yb}2 (μ,1κ(2) O(1,3) ,2κ(2) O(2,4) -S2 O4 )] (2). After extraction of 1, the mixture was heated to give the dinuclear tetrasulfinate complex [{(η(5) -C5 Me5 )Yb}2 (μ,κO,κO'-C5 Me5 SO2 )4 ] (3 a). In contrast, from the reaction of [(η(5) -C5 Me5 )2 Eu(THF)2 ] with SO2 only the tetrasulfinate complex [{(η(5) -C5 Me5 )Eu}2 (μ,κO,κO'-C5 Me5 SO2 )4 ] (3 b) was isolated. Two major reaction pathways were observed: 1) reductive coupling of two SO2 molecules to form the dithionite anion S2 O4 (2-) ; and 2) nucleophilic attack of one metallocene C5 Me5 ligand on the sulfur atom of SO2 . The compounds presented are the first dithionite and sulfinate complexes of the f-elements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Tetranuclear hetero-metal [Co(II)2Ln(III)2] (Ln = Gd, Tb, Dy, Ho, La) complexes involving carboxylato bridges in a rare μ4-η(2):η(2) mode: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Abtab, Sk Md Towsif; Majee, Mithun Chandra; Maity, Manoranjan; Titiš, Ján; Boča, Roman; Chaudhury, Muktimoy

    2014-02-03

    A new family of 3d-4f heterometal 2 × 2 complexes [Co(II)2(L)2(PhCOO)2Ln(III)2(hfac)4] (1-5) (Ln = Gd (compound 1), Tb (compound 2), Dy (compound 3), Ho (compound 4), and La (compound 5)) have been synthesized in moderate yields (48-63%) following a single-pot protocol using stoichiometric amounts (1:1 mol ratio) of [Co(II)(H2L)(PhCOO)2] (H2L = N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine) as a metalloligand and [Ln(III)(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) as a lanthanide precursor compound. Also reported with this series is the Zn-Dy analog [Zn(II)2(L)2(PhCOO)2Dy(III)2(hfac)4] 6 to help us in understanding the magnetic properties of these compounds. The compounds 1-6 are isostructural. Both hexafluoroacetylacetonate and benzoate play crucial roles in these structures as coligands in generating a tetranuclear core of high thermodynamic stability through a self-assembly process. The metal centers are arranged alternately at the four corners of this rhombic core, and the carboxylato oxygen atoms of each benzoate moiety bind all of the four metal centers of this core in a rare μ4-η(2):η(2) bridging mode as confirmed by X-ray crystallography. The magnetic susceptibility and magnetization data confirm a paramagnetic behavior, and no remnant magnetization exists in any of these compounds at vanishing magnetic field. The metal centers are coupled in an antiferromagnetic manner in these compounds. The [Co(II)2Dy(III)2] compound exhibits a slow magnetic relaxation below 6 K, as proven by the AC susceptibility measurements; the activation energy reads U/kB = 8.8 K (τ0 = 2.0 × 10(-7) s) at BDC = 0, and U/kB = 7.8 K (τ0 = 3.9 × 10(-7) s) at BDC = 0.1 T. The [Zn(II)2Dy(III)2] compound also behaves as a single-molecule magnet with U/kB = 47.9 K and τ0 = 2.75 × 10(-7) s.

  7. A Family of {Cr(III)2Ln(III)2} Butterfly Complexes: Effect of the Lanthanide Ion on the Single-Molecule Magnet Properties.

    Science.gov (United States)

    Langley, Stuart K; Wielechowski, Daniel P; Chilton, Nicholas F; Moubaraki, Boujemaa; Murray, Keith S

    2015-11-02

    We report the synthesis of several heterometallic 3d-4f complexes which result from the replacement of the Dy(III) ions in the [Cr(III)2Dy(III)2(OMe)2(mdea)2(O2CPh)4(NO3)2] single-molecule magnet (SMM) by the trivalent Pr, Nd, Gd, Tb, Ho, and Er lanthanide ions. The parent {Cr2Dy(III)2} compound displayed an anisotropy barrier to magnetization reversal of 53 cm(-1), with magnetic hysteresis observed up to 3.5 K and with large coercive fields at low temperatures (2.7 T at 1.8 K). Magnetic studies for the new complexes revealed significantly different static and dynamic magnetic behavior in comparison to the parent {Cr(III)2Dy(III)2} complex. When Ln(III) = Pr, a complete loss of SMM behavior is found, but when Ln(III) = Nd or Er, frequency-dependent tails in the out-of-phase susceptibility at low temperatures are observed, indicative of slow magnetic relaxation, but with very small anisotropy barriers and fast relaxation times. When Ln(III) = Tb and Ho, SMM behavior is clearly revealed with anisotropy barriers of 44 and 36 cm(-1), respectively. Magnetic hysteresis is also observed up to 2.5 and 1.8 K (0.003 T/s) for the Tb and Ho complexes, respectively. A large loss of the magnetization is, however, observed at zero-field, and as a result, the large coercivity which is present in the {Cr2Dy2} example is lost. The {Cr2Tb2} and {Cr2Ho2} complexes are rare examples of Tb- and Ho-based SMMs which reveal both slow relaxation in the absence of a static dc field (ac susceptibility) and open hysteresis loops above 1.8 K.

  8. Magnetic anisotropy and exchange coupling in a family of isostructural Fe(III)2Ln(III)2 complexes.

    Science.gov (United States)

    Baniodeh, Amer; Lan, Yanhua; Novitchi, Ghenadie; Mereacre, Valeriu; Sukhanov, Andrey; Ferbinteanu, Marilena; Voronkova, Violeta; Anson, Christopher E; Powell, Annie K

    2013-06-28

    The reaction of [Fe3O(O2CPh)6(H2O)3](O2CPh) with lanthanide/rare earth nitrate salts in the presence of triethanolamine (H3tea) in acetonitrile/methanol solution yields a series of compounds with isostructural tetranuclear core motifs [Fe(III)2Ln(III)2(μ3-OH)2(teaH)2(O2CCPh)6]·3MeCN (Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), Yb (12), Y (13)). In all cases the core topology is a defect-dicubane planar or "butterfly" Fe2Ln2 motif. Compounds 1-13 were investigated using a combination of experimental techniques and theoretical studies. Magnetic susceptibility measurements were carried out on all compounds. The magnetic coupling between the two Fe(III) centres is antiferromagnetic, with J(FeFe) ca.-6.71(4) cm(-1), while the Fe-Ln couplings are much weaker, e.g. J(FeGd) = 0.18(1) cm(-1). Compounds 6, 7, 8 and 13 were selected for Mössbauer studies in order to investigate the influence of isotropic (Gd(III)), highly anisotropic non-Kramers and Kramers (Tb(III) and Dy(III)) and diamagnetic (Y(III)) rare earth ions on the local environment of the Fe(III) centres. Compounds 3, 6, 8 and 13 were also studied using X-Band EPR spectroscopy. For 13, with the diamagnetic Y(III) ion, this made it possible to obtain the D, E, J(FeFe) and g parameters for the iron centres. It is shown that the low-temperature spectra of compounds 3, 6 and 8 are determined by magnetic properties of rare-earth ions and the dipole-dipole interactions between the Ln(III) ions. The Fe-Ln interactions were confirmed as very weak and dipolar in nature by the temperature dependence of EPR spectra at T > 20 K.

  9. Octanuclear {Ln(III)8}(Ln = Gd, Tb, Dy, Ho) macrocyclic complexes in a cyclooctadiene-like conformation: manifestation of slow relaxation of magnetization in the Dy(III) derivative.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Bag, Prasenjit; Colacio, Enrique

    2013-04-15

    The synthesis of a series of macrocyclic, isostructural octanuclear lanthanide complexes [Gd8 (LH2)4 (μ-Piv)4 (η(2)-Piv)4 (μ-OMe)4]·6CH3OH·2H2O (1), [Tb8 (LH2)4 (μ-Piv)4 (η(2)-Piv)4 (μ-OMe)4]4CH3OH·4H2O (2), [Dy8(LH2)4 (μ-Piv)4 (η(2)-Piv)4 (μ-OMe)4]·8CH3OH (3), and [Ho8(LH2)4(μ-Piv)4 (η(2)-Piv)4 (μ-OMe)4]·CH3OH·4H2O (4) have been achieved, using Ln(III) nitrate salts, pivalic acid, and a new multidentate chelating ligand (2E,N'E)-N'-(3-((bis(2- hydroxyethyl)amino)methyl)-2-hydroxy-5-methylbenzylidene)-2-(hydroxyimino) propane hydrazide (LH5), containing two unsymmetrically disposed arms; one side of the phenol unit is decorated with a diethanolamine group while the other side is a hydrazone that has been built by the condensation reaction involving 2-hydroxyiminopropanehydrazide. All the compounds, 1-4, are neutral and are held by the four [LH2](3-) triply deprotonated chelating ligands. In these complexes all the lanthanide ions are doubly or triply bridged via phenolate, alkoxy, and pivalate oxygens. The metal centers are distributed over the 8 vertices of an octagon, resembling a cyclooctadiene ring core. The details of magnetochemical analysis for complexes 1-4 shows that they exhibit antiferromagnetic interactions between the Ln(3+) ions through the phenoxo, alkoxo, and pivalato bridging groups. None of the compounds exhibits slow relaxation of the magnetization at zero applied direct current (dc) magnetic field, which could be due to the existence of a fast quantum tunneling relaxation of the magnetization (QTM). In the case of 3, the application of a small dc field is enough as to fully or partly suppress the fast and efficient zero-field QTM allowing the observation of slow relaxation above 2 K.

  10. Stability and Unimolecular Reactivity of Palladate(II) Complexes [Ln PdR3 ](-) (L=Phosphine, R=Organyl, n=0 and 1).

    Science.gov (United States)

    Kolter, Marlene; Koszinowski, Konrad

    2016-10-24

    The reduction of Pd(II) precatalysts to catalytically active Pd(0) species is a key step in many palladium-mediated cross-coupling reactions. Besides phosphines, the stoichiometrically used organometallic reagents can afford this reduction, but do so in a poorly understood way. To elucidate the mechanism of this reaction, we have treated solutions of Pd(OAc)2 and a phosphine ligand L in tetrahydrofuran with RMgCl (R=Ph, Bn, Bu) as well as other organometallic reagents. Analysis of these model systems by electrospray- ionization mass spectrometry found palladate(II) complexes [Ln PdR3 ](-) (n=0 and 1), thus pointing to the occurrence of transmetallation reactions. Upon gas-phase fragmentation, the [Ln PdR3 ](-) anions preferentially underwent a reductive elimination to yield Pd(0) species. The sequence of the transmetallation and reductive elimination, thus, constitutes a feasible mechanism for the reduction of the Pd(OAc)2 precatalyst. Other species of interest observed include the Pd(IV) complex [PdBn5 ](-) , which did not fragment via a reductive elimination but lost BnH instead. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. DFT study of electron absorption and emission spectra of pyramidal LnPc(OAc) complexes of some lanthanide ions in the solid state.

    Science.gov (United States)

    Hanuza, J; Godlewska, P; Lisiecki, R; Ryba-Romanowski, W; Kadłubański, P; Lorenc, J; Łukowiak, A; Macalik, L; Gerasymchuk, Yu; Legendziewicz, J

    2018-01-04

    The electron absorption and emission spectra were measured for the pyramidal LnPc(OAc) complexes in the solid state and co-doped in silica glass, where Ln=Er, Eu and Ho. The theoretical electron spectra were determined from the quantum chemical DFT calculation using four approximations CAM-B3LYP/LANL2DZ, CAM-B3LYP/CC-PVDZ, B3LYP/LANL2DZ and B3LYP/CC-PVDZ. It was shown that the best agreement between the calculated and experimental structural parameters and spectroscopic data was reached for the CAM-B3LYP/LANL2DZ model. The emission spectra were measured using the excitations both in the ligand and lanthanide absorption ranges. The possibility of energy transfer between the phthalocyanine ligand and excited states of lanthanide ions was discussed. It was shown that the back energy transfer from metal states to phthalocyanine state is responsible for the observed emission of the studied complexes both in the polycrystalline state and silica glass. Copyright © 2018. Published by Elsevier B.V.

  12. Carboxylate-bridged copper(II)-lanthanide(III) complexes [(Cu(3)Ln(2)(oda)(6)(H(2)O)(6)).12H(2)O](n)(Ln = Dy, Ho, Er, Y; oda = oxydiacetate).

    Science.gov (United States)

    Rizzi, Alberto C; Calvo, Rafael; Baggio, Ricardo; Garland, María Teresa; Peña, Octavio; Perec, Mireille

    2002-10-21

    The hydrothermal reaction of Ln(2)O(3) (Ln = Dy and Ho), Cu(OAc)(2).2H(2)O, and oxydiacetic acid in the approximate mole ratio of 1:3:8 resulted in the formation of two new members of the isostructural series of polymers formulated as [(Cu(3)Ln(2)(oda)(6)(H(2)O)(6)).12H(2)O](n), crystallizing in the hexagonal crystal system, space group P6/mcc (No. 192). Temperature-dependent magnetic susceptibilities and EPR spectra are reported for the heterometallic compounds Cu-Dy 1, Cu-Ho 2, Cu-Er 3, and Cu-Y 4. The results are discussed in terms of the structure of the compounds, the electronic properties of the lanthanide ions, and the exchange interactions between the magnetic ions.

  13. Assembly of heterobimetallic Ni(II)-Ln(III) (Ln(III) = Dy(III), Tb(III), Gd(III), Ho(III), Er(III), Y(III)) complexes using a ferrocene ligand: slow relaxation of the magnetization in Dy(III), Tb(III) and Ho(III) analogues.

    Science.gov (United States)

    Chakraborty, Amit; Bag, Prasenjit; Rivière, Eric; Mallah, Talal; Chandrasekhar, Vadapalli

    2014-06-21

    A family of dinuclear 3d-4f heterobimetallic complexes [LNi(H2O)(μ-OAc)Ln(NO3)2]·CH3CN; {Ln = Dy(III) (1), Tb(III) (2), Ho(III) (3), Gd(III) (4), Er(III) (5), Y(III) (6)} have been synthesized by utilizing a ferrocene-based, dual compartmental ligand H2L. 1-6 are isostructural and crystallize in the triclinic (P1) space group. In these complexes Ni(II) is present in the inner coordination sphere of the dianionic [L](2-) ligand; Ln(III) is encapsulated in the outer coordination pocket. Ni(II) shows a 2N, 4O coordination environment in a distorted octahedral geometry, while the Ln(III) ion possesses a 9O coordination environment in a distorted tricapped trigonal prismatic geometry. ESI-MS studies suggest that the structural integrity of 1-6 is retained in solution. Electrochemical studies reveal that these complexes show a reversible one-electron response typical of the ferrocene motif along with an irreversible one-electron oxidation involving the Ni(II)/Ni(III) couple. Magnetic studies revealed the presence of ferromagnetic exchange coupling between Ni(II) and Ln(III) centers as shown by the increase of χMT value upon cooling below 50 K for compounds 1, 2, 4 and 5. Further, dynamic magnetic susceptibility measurements (1-3) confirm the absence of an out-of-phase (χ'') signal at zero dc fields. However, when these measurements were carried out at 1000 Oe dc field the χ'' signal was observed, although maxima could not be detected up to 2 K.

  14. 2-D and 3-D phosphotungstate-based TM-Ln heterometallic derivatives constructed from dimeric [Ln({alpha}-PW{sub 11}O{sub 39}){sub 2}]{sup 11-} fragments and copper-organic complex linkers

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Sensen [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Zhao, Junwei, E-mail: zhaojunwei@henu.edu.cn [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Chen, Lijuan [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Basic Experiment Teaching Center, Henan University, Kaifeng, Henan 475004 (China); Li, Yuye; Zhang, Jingli; Li, Yanzhou [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Niu, Jingyang, E-mail: jyniu@henu.edu.cn [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China)

    2012-12-15

    Three organic-inorganic hybrid TM-Ln heterometallic phosphotungstates [Cu(dap){sub 2}(H{sub 2}O)][Cu(dap){sub 2}]{sub 3.5}[La({alpha}-HPW{sub 11}O{sub 39}){sub 2}]{center_dot}6H{sub 2}O (1) [Cu(dap){sub 2}(H{sub 2}O)]{sub 0.5}[Cu(dap){sub 2}]{sub 4}[Nd({alpha}-HPW{sub 11}O{sub 39}){sub 2}]{center_dot}4H{sub 2}O (2) and [Cu(dap){sub 2}(H{sub 2}O)]{sub 2}[Cu(dap){sub 2}]{sub 3.5}[Eu({alpha}-PW{sub 11}O{sub 39}){sub 2}]{center_dot}6H{sub 2}O (3) (dap=1,2-diaminopropane) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, optical diffuse reflectance spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analyses and single-crystal X-ray diffraction. Their common features are that 1-3 all consist of asymmetric sandwich-type subunits [Ln({alpha}-PW{sub 11}O{sub 39}){sub 2}]{sup 11-} and [Cu(dap){sub 2}]{sup 2+} bridges. Both 1 and 2 display the 2-D (4,4)-topological sheets whereas 3 exhibits the 3-D 5-connected (4{sup 6}{center_dot}6{sup 4}) topological framework. The magnetic properties of 2 and 3 and the luminescence performance of 3 have been measured. - Graphical Abstract: Three TM-Ln heterometallic phosphotungstates 1-3 have been synthesized and characterized by elemental analyses, IR spectra, optical diffuse reflectance spectra, X-ray diffraction, thermogravimetric analyses magnetic susceptibility and luminescent properties. Highlights: Black-Right-Pointing-Pointer Cu{sup II}-Ln{sup III} heterometallic polyoxometalates. Black-Right-Pointing-Pointer 2-D and 3-D organic-inorganic hybrid phosphotungstates. Black-Right-Pointing-Pointer 2-D and 3-D structures consisting of Cu{sup II}-Ln{sup III} heterometals.

  15. The interplay between lnRNAs, SNPs, and protein complexes - what does it mean for cancer metabolism?

    Science.gov (United States)

    Redis, Roxana S; Calin, George A

    2016-07-01

    Long non-coding RNAs (lncRNAs) exert most of their functions through protein interactions. A better understanding of these interactions will facilitate the development of novel therapeutics. Recently, we described how the lncRNA CCAT2 located at the 8q24 cancer amplicon reprograms cancer metabolism by directly interacting in an allele-specific manner with a protein complex.

  16. Solvothermal synthesis and spectroscopic characterization of three lanthanide complexes with high luminescent properties [H2NMe2]3[Ln(III)(2,6-pyridinedicarboxylate)3] (Ln = Sm, Eu, Tb): In the presence of 4,4‧-Bipyridyl

    Science.gov (United States)

    Viveros-Andrade, Alan G.; Colorado-Peralta, Raúl; Flores-Alamo, Marcos; Castillo-Blum, Silvia E.; Durán-Hernández, Jesús; Rivera, José María

    2017-10-01

    Three lanthanide complexes, [H2NMe2]3[Ln(III)(2,6-pyridinedicarboxylate)3] (Ln = Sm, Eu, Tb) have been successfully synthesized using a solvothermal method in the presence of a base and they were prepared from inexpensive and readily available reactants. Infrared, ultraviolet-visible absorption spectroscopies, elemental analyses and thermogravimetric analysis were employed for the characterization. Crystals suitable for X-ray diffraction were isolated in good yields by a simple filtration, their crystal structures were analyzed; the samarium structure has orthorhombic symmetry with space group Pbcn, exhibiting three-dimensional supramolecular architecture through hydrogen bonding interactions. The metal center is coordinated to nine atoms corresponding to three pyridine-2,6-dicarboxylic acid molecules. These compounds are thermally stable up to 270 °C.

  17. Syntheses, structures, and magnetic properties of a family of heterometallic heptanuclear [Cu5Ln2] (Ln = Y(III), Lu(III), Dy(III), Ho(III), Er(III), and Yb(III)) complexes: observation of SMM behavior for the Dy(III) and Ho(III) analogues.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Dey, Atanu; Das, Sourav; Rouzières, Mathieu; Clérac, Rodolphe

    2013-03-04

    Sequential reaction of the multisite coordination ligand (LH3) with Cu(OAc)2·H2O, followed by the addition of a rare-earth(III) nitrate salt in the presence of triethylamine, afforded a series of heterometallic heptanuclear complexes containing a [Cu5Ln2] core {Ln = Y(1), Lu(2), Dy(3), Ho(4), Er(5), and Yb(6)}. Single-crystal X-ray crystallography reveals that all the complexes are dicationic species that crystallize with two nitrate anions to compensate the charge. The heptanuclear aggregates in 1-6 are centrosymmetrical complexes, with a hexagonal-like arrangement of six peripheral metal ions (two rare-earth and four copper) around a central Cu(II) situated on a crystallographic inversion center. An all-oxygen environment is found to be present around the rare-earth metal ions, which adopt a distorted square-antiprismatic geometry. Three different Cu(II) sites are present in the heptanuclear complexes: two possess a distorted octahedral coordination sphere while the remaining one displays a distorted square-pyramidal geometry. Detailed static and dynamic magnetic properties of all the complexes have been studied and revealed the single-molecule magnet behavior of the Dy(III) and Ho(III) derivatives.

  18. A family of 'windmill'-like {Cu6Ln12} complexes exhibiting single-molecule magnetism behavior and large magnetic entropy changes.

    Science.gov (United States)

    Alexandropoulos, Dimitris I; Poole, Katye M; Cunha-Silva, Luis; Ahmad Sheikh, Javeed; Wernsdorfer, Wolfgang; Christou, George; Stamatatos, Theocharis C

    2017-04-11

    A family of nanosized {Cu6Ln12} clusters with a 'windmill'-like topology was prepared from the employment of 2,6-diacetylpyridine dioxime, in conjunction with bridging N3-, in 3d/4f-metal chemistry; the octadecanuclear compounds exhibit single-molecule magnetism behavior and large magnetic entropy changes, depending on the 4f-metal ion present.

  19. Highly efficient near-infrared-emitting lanthanide(III) complexes formed by heterogeneous self-assembly of Ag(I), Ln(III), and thiacalix[4]arene-p-tetrasulfonate in aqueous solution (Ln(III) = Nd(III), Yb(III)).

    Science.gov (United States)

    Iki, Nobuhiko; Hiro-oka, Shouichi; Tanaka, Teppei; Kabuto, Chizuko; Hoshino, Hitoshi

    2012-02-06

    Heterogeneous self-assembly of thiacalix[4]arene-p-tetrasulfonate (TCAS), Ag(I), and Ln(III) (= Nd(III), Yb(III)) in aqueous solutions conveniently afforded ternary complexes emitting Ln(III)-centered luminescence in the near-infrared (NIR) region. A solution-state study revealed that the Ag(I)-Nd(III)-TCAS system gave a complex Ag(I)(4)·Nd(III)·TCAS(2) in a wide pH range of 6-12. In contrast, the Ag(I)-Yb(III)-TCAS system gave Ag(I)(2)·Yb(III)(2)·TCAS(2) at a pH of around 6 and Ag(I)(2)·Yb(III)·TCAS(2) at a pH of approximately 9.5. The structures of the Yb(III) complexes were proposed based on comparison with known Ag(I)-Tb(III)-TCAS complexes that show the same self-assembly behavior. In Ag(I)(2)·Yb(III)(2)·TCAS(2), two TCAS ligands sandwiched a cyclic array of a Ag(I)-Ag(I)-Yb(III)-Yb(III) core. In Ag(I)(2)·Yb(III)·TCAS(2), Yb(III) was accommodated in an O(8) cube consisting of eight phenolate O(-) groups from two TCAS ligands linked by two S-Ag-S linkages. Crystallographic analysis of Ag(I)(4)·Nd(III)·TCAS(2) revealed that the structure was similar to Ag(I)(2)·Yb(III)·TCAS(2) but that it had four instead of two S-Ag-S linkages. The number of water molecules coordinating to Ln(III) (q) estimated on the basis of the luminescent lifetimes was as follows: Ag(I)(4)·Nd(III)·TCAS(2), 0; Ag(I)(2)·Yb(III)(2)·TCAS(2), 2.4; and Ag(I)(2)·Yb(III)·TCAS(2), 0. These findings were compatible with the solution-state structures. The luminescent quantum yield (Φ) for Ag(I)(4)·Nd(III)·TCAS(2) was 4.9 × 10(-4), which is the second largest value ever reported in H(2)O. These findings suggest that the O(8) cube is an ideal environment to circumvent deactivation via O-H oscillation of coordinating water. The Φ values for Ag(I)(2)·Yb(III)(2)·TCAS(2) and Ag(I)(2)·Yb(III)·TCAS(2) were found to be 3.8 × 10(-4) and 3.3 × 10(-3), respectively, reflecting the q value. Overall, these results indicate that the ternary systems have the potential for a noncovalent

  20. Luminescent properties and structure of new CAPh-based lanthanide complexes [LnL3Q], containing additional bis-heterocyclic aromatic ligand-antenna 2-(1,3,4-oxadiazole-2-yl) pyridine

    Science.gov (United States)

    Yakovlev, Oleksii O.; Kariaka, Nataliia S.; Trush, Victor A.; Smola, Sergii S.; Siczek, Milosz; Amirkhanov, Vladimir M.

    2018-01-01

    The new lanthanide coordination compounds of general formula [LnL3Q], where Ln = Eu, Gd, Tb; L = dimethyl-N-trichloroacetylamidophosphate and Q = 2-(1,3,4-oxadiazole-2-yl)pyridine, have been synthesized and isolated in crystalline state with the purpose of finding new interesting optical materials. X-ray data reveal that complexes have molecular structure with numerous Van-der-Vaals contacts between molecules. All the ligands are coordinated in bidentate chelate manner, coordination polyhedron was interpreted as distored square antiprism (CN 8). The obtained complexes were investigated by means of IR, absorption and luminescence spectroscopy as well and thermal gravimetric analysis. It was found that complex [TbL3Q] is resistant to temperature of 200 °C. The Eu3+ and Tb3+ complexes exhibit bright metal-centered emission with decay time 1.65 and 1.74 ms respectively. Intrinsic quantum yield for [EuL3Q] equals 85% that is one of the highest values, known to date for CAPh based europium complexes.

  1. Lanthanide(III) complexes with μ-SnSe{sub 4} and μ-Sn{sub 2}Se{sub 6} linkers. Solvothermal syntheses and properties of new Ln(III) selenidostannates decorated with linear polyamine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuzhen; Sun, Peipei; Shen, Yali; Han, Jingyu; Sun, Hui; Jia, Dingxian [Soochow Univ., Suzhou (China). College of Chemistry, Chemical Engineering and Materials Science

    2017-06-01

    New lanthanide-selenidostannate complexes [{La(peha)(Cl)}{La(peha)(NO_3)}(μ-1κ{sup 2}:2κ{sup 2}-SnSe{sub 4})] (1), [H{sub 2}trien][{La(trien)_2}{sub 2}(μ-1-κ:2κ-Sn{sub 2}Se{sub 6})][Sn{sub 2}Se{sub 6}].H{sub 2}O (2) and [{Ln(tepa)(μ-OH)}{sub 2}(μ-1κ:2κ-Sn{sub 2}Se{sub 6})]{sub n}.nH{sub 2}O (Ln=Sm(3), Eu(4)) were prepared by solvothermal methods in pentaethylenehexamine (peha), triethylenetetramine (trien) and tetraethylenepentamine (tepa), respectively. Acting as a tetradentate chelating and bridging ligand, μ-1κ{sup 2}:2κ{sup 2}-SnSe{sub 4}, the tetrahedral SnSe{sub 4} unit joins {La(peha)(Cl)}{sup 2+} and {La(peha)(NO_3)}{sup 2+} complex fragments to generate the neutral coordination compound 1. The tetradentate μ-1κ{sup 2}:2κ{sup 2} bridge in 1 represents a new coordination mode for the SnSe{sub 4} tetrahedron. In 2, dinuclear [Sn{sub 2}Se{sub 6}]{sup 4-} anions are formed of SnSe{sub 4} tetrahedra via edge-sharing. One [Sn{sub 2}Se{sub 6}]{sup 4-} anion acts as a bidentate bridging ligand in a μ-1κ:2κ coordination mode to join two {La(trien)_2}{sup 3+} units, and the other [Sn{sub 2}Se{sub 6}]{sup 4-} anion exists as a free charge compensating ion. In 3 and 4, the [Sn{sub 2}Se{sub 6}]{sup 4-} anion connects binuclear [{Ln(tepa)(μ-OH)}{sub 2}]{sup 2+}(Ln=Sm, Eu) units with a bidentate μ-1κ:2κ mode, giving neutral coordination polymers [{Ln(tepa)(μ-OH)}{sub 2}(μ-1κ:2κ-Sn{sub 2}Se{sub 6})]{sub n}. The La(2){sup 3+} ion in 1 is in a 10-fold coordination environment of LaN{sub 6}O{sub 2}Se{sub 2}, whereas the La(1){sup 3+} ions in 1 and 2 are in 9-fold coordinated environments forming polyhedra LaN{sub 6}ClSe{sub 2} and LaN{sub 8}Se, respectively. The Sm{sup 3+} and Eu{sup 3+} ions in 3 and 4 are both in an 8-fold coordination environment of LnN{sub 5}O{sub 2}Se. Compounds 1-4 exhibit optical band gaps between 2.21 and 2.42 eV. Their thermal stabilities were investigated by thermogravimetric analyses.

  2. Complexation of trivalent actinides and lanthanides with hydrophilic N-donor ligands for Am(III)/Cm(III) and An(III)/Ln(III) separation; Komplexierung von trivalenten Actiniden und Lanthaniden mit hydrophilen N-Donorliganden zur Am(III)/Cm(III)- bzw. An(III)/Ln(III)-Trennung

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Christoph

    2017-07-24

    The implementation of actinide recycling processes is considered in several countries, aiming at the reduction of long-term radiotoxicity and heat load of used nuclear fuel. This requires the separation of the actinides from the fission and corrosion products. The separation of the trivalent actinides (An(III)) Am(III) and Cm(III), however, is complicated by the presence of the chemically similar fission lanthanides (Ln(III)). Hydrophilic N-donor ligands are employed as An(III) or Am(III) selective complexing agents in solvent extraction to strip An(III) or Am(III) from an organic phase loaded with An(III) and Ln(III). Though they exhibit excellent selectivity, the complexation chemistry of these ligands and the complexes formed during solvent extraction are not sufficiently characterized. In the present thesis the complexation of An(III) and Ln(III) with hydrophilic N-donor ligands is studied by time resolved laser fluorescence spectroscopy (TRLFS), UV/Vis, vibronic sideband spectroscopy and solvent extraction. TRLFS studies on the complexation of Cm(III) and Eu(III) with the Am(III) selective complexing agent SO{sub 3}-Ph-BTBP (tetrasodium 3,3{sup '},3'',3{sup '''}-([2,2{sup '}-bipyridine]-6,6{sup '}-diylbis(1,2,4-triazine-3,5,6-triyl)) tetrabenzenesulfonate) revealed the formation of [M(SO{sub 3}-Ph-BTBP){sub n}]{sup (4n-3)-} complexes (M = Cm(III), Eu(III); n = 1, 2). The conditional stability constants were determined in different media yielding two orders of magnitude larger β{sub 2}-values for the Cm(III) complexes, independently from the applied medium. A strong impact of ionic strength on the stability and stoichiometry of the formed complexes was identified, resulting from the stabilization of the pentaanionic [M(SO{sub 3}-Ph-BTBP){sub 2}]{sup 5-} complex with increasing ionic strength. Thermodynamic studies of Cm(III)-SO{sub 3}-Ph-BTBP complexation showed that the proton concentration of the applied medium impacts

  3. (Ln=La-Lu) Diatom

    Indian Academy of Sciences (India)

    LnSi diatoms is carried out taking relativistic effect into account. In order to reveal the unusual properties of the rare earth Ln and silicon clusters, the main objective of this research, therefore, is to provide a detailed investigation of equilibrium geometries, charge-transfer properties, ionization potentials (IPs), electron affinitie ...

  4. Synthesis and Photoluminescent Properties of Nanorod Bundle Ln4O(OH)9NO3:Eu(Ln = Y, Lu) Prepared by Hydrothermal Method.

    Science.gov (United States)

    Li, Ling; Noh, Hyeon Mi; Liu, Xiaoguang; Moon, Byung Kee; Choi, Byung Chun; Jeong, Jung Hyun

    2015-07-01

    Well-crystallized nanorod bundles Ln4O(OH)9NO3:1%Eu(Ln = Y, Lu) have been successfully prepared by hydrothermal method. The crystalline phase, size and optical properties were characterized using powder X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), infrared (IR) spectrograph and photoluminescent (PL) spectra. Site occupations of Eu3+ in crystals Ln4O(OH)9NO3:Eu(Ln = Y, Lu) were discussed based on excitation spectra and the empirical relationship formula between the charge transfer (CT) energy and the environmental factor. The emission spectra exhibited that the strongest emission peaks with an excitation wavelength of 395 nm were at 617 and 626 nm in crystal Lu4O(OH)9NO3:1%Eu and Y4O(OH)9NO3:1%Eu, respectively, both of which come from 5D0-7F2 transition of the Eu3+ ions. The broad excitation peaks at about 254 and 255 nm were found when monitored at 617 and 628 nm in crystal Lu4O(OH)9NO3:1%Eu and Y4O(OH)9NO3:1%Eu, respectively, which were due to O-Eu CT transition. Based on the dielectric theory of complex crystal, the CT bands at about 254 and 255 nm in Ln4O(OH)9NO3:1%Eu(Ln = Y, Lu) were assigned to the transition of O-Eu at Ln3(Ln = Y, Lu) site, from which we can conclude that Eu3+ ions occupied the site of Ln3(Ln = Y, Lu) in crystal Ln4O(OH)9NO3:1%Eu(Ln = Y, Lu). It put forward a new route to investigate site occupation of luminescent center ions in rare earth doped complex inorganic luminescence materials.

  5. Ln(iii)-complexes of a DOTA analogue with an ethylenediamine pendant arm as pH-responsive PARACEST contrast agents.

    Science.gov (United States)

    Krchová, T; Gálisová, A; Jirák, D; Hermann, P; Kotek, J

    2016-02-28

    A novel macrocyclic DO3A derivative containing a linear diamine pendant arm, H3do3aNN, was prepared and its protonation and complexation properties were studied by means of potentiometry. It determined ligand consecutive protonation constants log K(An) = 12.62, 10.28, 9.67, 8.30, 3.30 and 1.58 and stability constants of selected lanthanide (Eu(iii), Yb(iii)) complexes log K(EuL) = 23.16 and log KYbL = 22.76. The complexes could be protonated on the pendant amino group(s) with log K(HLM) ≈ 5.6 and log K(H2LM) ≈ 4.8. Solution structures of both complexes were studied by NMR spectroscopy. The study revealed that the complex species exist exclusively in the form of twisted-square-antiprismatic (TSA) isomers. The complexes show significant pH dependence of the Chemical Exchange Saturation Transfer (CEST) between their amino groups and the bulk water molecules in the pH range of 5-8. Thus, the pH dependence of the magnetization transfer ratio of CEST signals can be used for pH determination using magnetic resonance imaging techniques in a pH range relevant for in vivo conditions.

  6. Interaction of ionic biomolecular building blocks with nonpolar solvents: acidity of the imidazole cation (Im+) probed by IR spectra of Im+-Ln complexes (L = Ar, N2; n < or = 3).

    Science.gov (United States)

    Andrei, Horia-Sorin; Solcà, Nicola; Dopfer, Otto

    2005-04-28

    The intermolecular interaction between the imidazole cation (Im+ = C3N2H4+) and nonpolar ligands is characterized in the ground electronic state by infrared photodissociation (IRPD) spectroscopy of size-selected Im+-Ln complexes (L = Ar, N2) and quantum chemical calculations performed at the UMP2/6-311G(2df,2pd) and UB3LYP/6-311G(2df,2pd) levels of theory. The complexes are created in an electron impact cluster ion source, which predominantly produces the most stable isomers of a given cluster ion. The analysis of the size-dependent frequency shifts of both the N-H and the C-H stretch vibrations and the photofragmentation branching ratios provides valuable information about the stepwise microsolvation of Im+ in a nonpolar hydrophobic environment, including the formation of structural isomers, the competition between various intermolecular binding motifs (H-bonding and pi-bonding) and their interaction energies, and the acidity of both the CH and NH protons. In line with the calculations, the IRPD spectra show that the most stable Im+-L dimers feature planar H-bound equilibrium structures with nearly linear H-bonds of L to the acidic NH group of Im+. Further solvation occurs at the aromatic ring of Im+ via the formation of intermolecular pi-bonds. Comparison with neutral Im-Ar demonstrates the drastic effect of ionization on the topology of the intermolecular potential, in particular in the preferred aromatic substrate-nonpolar recognition motif, which changes from pi-bonding to H-bonding. .

  7. Structures and magnetic properties of double perovskites A sub 2 LnMO sub 6 and 6H-perovskites Ba sub 3 LnRu sub 2 O sub 9 (A=Sr, Ba; Ln=Y, lanthanides; M=Nb, Ta, Ru)

    CERN Document Server

    Hinatsu, Y

    2003-01-01

    This account describes the synthesis, crystal structures and magnetic properties of double perovskites A sub 2 LnMO sub 6 and 6H-perovskites Ba sub 3 LnRu sub 2 O sub 9 (A=Sr, Ba; Ln=Y, lanthanides; M=Nb, Ta, Ru). The double perovskites A sub 2 LnMO sub 6 have two kinds of cations, Ln and M, in the B site of the perovskite ABO sub 3. These cations adopt the alternative ordered arrangement. Measurements of the magnetic susceptibility, specific heat, and powder neutron diffraction showed that all of the A sub 2 LnRuO sub 6 compounds exhibited an antiferromagnetic transition at low temperatures and a complex temperature dependence of the magnetic susceptibility below their transition temperatures. In these compounds, the magnetic interaction between the Ln (4f electrons) and Ru (4d electrons) ions via the Ln-O-Ru pathway contributes greatly to their magnetic cooperative phenomena. The structural and magnetic studies for the 6H-perovskites Ba sub 3 LnRu sub 2 O sub 9 show that the Ln cations occupy the corner-sha...

  8. Effect of inclining strain on the crystal lattice along an extended series of lanthanide hydroxysulfates Ln(OH)SO4 (Ln = Pr-Yb, except Pm).

    Science.gov (United States)

    Zehnder, Ralph A; Wilson, Christopher S; Christy, Hunter T; Harris, Kenneth S; Chauhan, Varun; Schutz, Victor; Sullivan, Matthew; Zeller, Matthias; Fronczek, Frank R; Myers, Jacob A; Dammann, Kyle; Duck, James; Smith, Peter M; Okuma, Antony; Johnson, Kristin; Sovesky, Robert; Stroudt, Cameron; Renn, Robert A

    2011-02-07

    A series of trivalent lanthanide hydroxysulfates, Ln(OH)SO(4), (Ln = Pr through Yb, except radioactive Pm) has been synthesized via hydrothermal methods from Ln(2)(SO(4))(3)·8H(2)O by reaction with aqueous NaOH at 170 °C in Teflon lined Parr steel autoclaves, and were characterized by single crystal X-ray diffraction and FT-IR spectroscopy. Two types of arrangements were found in the solid state. The lighter (Ln = Pr-Nd, Sm-Gd) and heavier lanthanide(III) hydroxysulfates (Tb-Yb) are each isostructural. Both structure types exhibit the monoclinic space group P2(1)/n, but the unit cell content is doubled with two crystallographically distinct LnO(8) polyhedra for the heavier lanthanide compounds. The lighter complexes maintain the coordination number 9, forming a three-dimensional extended lattice. The heavier counterparts exhibit the coordination number 8, and arrange as infinite columns of two crystallographically different LnO(8) polyhedra, while extending along the "c" axis. These columns of LnO(8) polyhedra are surrounded and separated by six columns of sulfate ions, also elongating in the "c" direction. The rigid sulfate entities seem to obstruct the closing in of the lighter LnO(9) polyhedra, and show an inclining degree of torsion into the "ac" layers. The crystal lattice of the lighter 4f complexes can sufficiently withstand the tension buildup, caused by the decreasing Ln(3+) radius, up to Gd(OH)SO(4). The energy profile of this structural arrangement then seems to exceed levels at which this structure type is favorable. The lattice arrangement of the heavier Ln-analogues seems to offer a lower energy profile. This appears to be the preferred arrangement for the heavier lanthanide hydroxysulfates, whose crystal lattice exhibits more flexibility, as the coordination sphere of these analogues is less crowded. The IR absorbance frequencies of the hydroxide ligands correlate as a function of the Ln(3+) ionic radius. This corresponds well with the X-ray single

  9. Mononuclear lanthanide single molecule magnets based on the polyoxometalates [Ln(W5O18)2]9- and [Ln(beta2-SiW11O39)2]13- (Ln(III) = Tb, Dy, Ho, Er, Tm, and Yb).

    Science.gov (United States)

    AlDamen, Murad A; Cardona-Serra, Salvador; Clemente-Juan, Juan M; Coronado, Eugenio; Gaita-Ariño, Alejandro; Martí-Gastaldo, Carlos; Luis, Fernando; Montero, Oscar

    2009-04-20

    The first two families of polyoxometalate-based single-molecule magnets (SMMs) are reported here. Compounds of the general formula [Ln(W(5)O(18))(2)](9-) (Ln(III) = Tb, Dy, Ho, and Er) and [Ln(SiW(11)O(39))(2)](13-) (Ln(III) = Tb, Dy, Ho, Er, Tm, and Yb) have been magnetically characterized with static and dynamic measurements. Slow relaxation of the magnetization, typically associated with SMM-like behavior, was observed for [Ln(W(5)O(18))(2)](9-) (Ln(III) = Ho and Er) and [Ln(SiW(11)O(39))(2)](13-) (Ln(III) = Dy, Ho, Er, and Yb). Among them, only the [Er(W(5)O(18))(2)](9-) derivative exhibited such a behavior above 2 K with an energy barrier for the reversal of the magnetization of 55 K. For a deep understanding of the appearance of slow relaxation of the magnetization in these types of mononuclear complexes, the ligand-field parameters and the splitting of the J ground-state multiplet of the lanthanide ions have been also estimated.

  10. New lanthanide hybrid as clustered infinite nanotunnel with 3D Ln-O-Ln framework and (3,4)-connected net.

    Science.gov (United States)

    Huang, You-gui; Wu, Ben-lai; Yuan, Da-qiang; Xu, Yan-qing; Jiang, Fei-long; Hong, Mao-chun

    2007-02-19

    A series of new lanthanide hybrids [Ln3(mu-OH)4 (2,5-pydc)(2,5-Hpydc)3(H2O)4]n (Ln = Gd (1), Dy (2), Er (3), Eu (4), Sm (5), Yb (6), Y (7); 2,5-pydc=pyridine-2,5-dicarboxylate), as clustered lanthanide oxide ring tunnels with helical dodecahedral chains and fully 3D Ln-O-Ln connectivity, has been hydrothermally synthesized and characterized. The inorganic skeleton of the hybrid can be specified by the Schläfli symbol (6210)2 (64102) as a single 3D (3,4)-connected net. The luminescence properties have been studied, and the results showed that the Dy(III) (2) and Eu(III) (4) complexes exhibited sensitized luminescence in the visible region. Variable-temperature magnetic susceptibility measurements of 1-6 showed that the complexes 1-3 are nearly paramagnets, whereas the depopulation of the Stark levels in complexes 4-6 leads to a continuous decrease in mu(eff) when the sample is cooled from 300 to 2 K.

  11. Ordered oxygen deficient '112'perovskites, LnBaCo2 O5⋅ 50 ...

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 32; Issue 3. Ordered oxygen deficient '112' perovskites, LnBaCo2O5.50+: complex magnetism and transport properties. B Raveau Md Motin Seikh V Pralong V Caignaert. Volume 32 Issue 3 June 2009 pp 305-312 ...

  12. Electronic Structure and Magnetic Anisotropy in Lanthanoid Single-Ion Magnets with C3 Symmetry: The Ln(trenovan) Series.

    Science.gov (United States)

    Lucaccini, Eva; Baldoví, José J; Chelazzi, Laura; Barra, Anne-Laure; Grepioni, Fabrizia; Costes, Jean-Pierre; Sorace, Lorenzo

    2017-04-17

    We report the syntheses and the magnetic characterization of a new series of lanthanide complexes, in which the Ce, Nd, Gd, Dy, Er, and Yb derivatives show single-molecule magnet behavior. These complexes, named Ln(trenovan), where H3trenovan is tris(((3-methoxysalicylidene)amino)ethyl)amine, exhibit trigonal symmetry and the Ln(III) ion is heptacoordinated. Their molecular structure is then very similar to that of the previously reported Ln(trensal) series, where H3trensal is 2,2',2″-tris(salicylideneimino)triethylamine. This prompted us to use the spectroscopic and magnetic properties of the Ln(trensal) family (Ln = Nd, Tb, Dy, Ho, Er, and Tm) to obtain a set of crystal-field parameters to be used as starting point to determine the electronic structures and magnetic anisotropy of the analogous Ln(trenovan) complexes using the CONDON computational package. The obtained results were then used to discuss the electron paramagnetic resonance (EPR) and ac susceptibility results. As a whole, the obtained results indicate for this type of complexes single-molecule magnet behavior is not related to the presence of an anisotropy barrier, due to a charge distribution of the ligand around the lanthanoid, which results in highly mixed ground states in terms of MJ composition of the states. The crucial parameter in determining the slow relaxation of the magnetization is then rather the number of unpaired electrons (only Kramers ions showing in-field slow relaxation) than the shape of the charge distribution for different Ln(III).

  13. Three-dimensional open-frameworks based on Ln(III) ions and open-/closed-shell PTM ligands: synthesis, structure, luminescence, and magnetic properties.

    Science.gov (United States)

    Datcu, Angela; Roques, Nans; Jubera, Véronique; Imaz, Inhar; Maspoch, Daniel; Sutter, Jean-Pascal; Rovira, Concepció; Veciana, Jaume

    2011-03-21

    A series of isostructural open-framework coordination polymers formulated as [Ln(dmf)(3)(ptmtc)] (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5); PTMTC = polychlorotriphenylmethyl tricarboxylate) and [Ln(dmf)(2)H(2)O(αH-ptmtc)] (Ln = Sm (1'), Eu (2'), Gd (3'), Tb (4'), Dy (5')) have been obtained by treating Ln(III) ions with PTMTC ligands with a radical (PTMTC(3-)) or a closed-shell character (αH-PTMTC(3-)). X-ray diffraction analyses reveal that these coordination polymers possess 3D architectures that combine large channels and fairly rare lattice complex T connectivity. In addition, these compounds show selective framework dynamic sorption properties. For both classes of ligands, the ability to act as an antenna in Ln sensitization processes has been investigated. No luminescence was observed for compounds 1-5, and 3' because of the PTMTC(3-) ligand and/or Gd(III) ion characteristics. Conversely, photoluminescence measurements show that 1', 2', 4', and 5' emit dark orange, red, green, and dark cyan metal-centered luminescence. The magnetic properties of all of these compounds have been investigated. The nature of the {Ln-radical} exchange interaction in these compounds has been assessed by comparing the behavior of the radical-based coordination polymers 1-5 with those of the compounds with the diamagnetic ligand set. While antiferromagnetic {Sm-radical} interactions are found in 1, ferromagnetic {Ln-radical} interactions propagate in the 3D architectures of 3, 4, and 5 (Ln = Gd, Tb, and Dy, respectively). This procedure also provided access to information on the {Ln-Ln} exchange existing in these magnetic systems. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Axially symmetric U-O-Ln- and U-O-U-containing molecules from the control of uranyl reduction with simple f-block halides

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Polly L.; Cowie, Bradley E.; Suvova, Marketa; Zegke, Markus; Love, Jason B. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom); Magnani, Nicola; Colineau, Eric; Griveau, Jean-Christophe; Caciuffo, Roberto [European Commission, Directorate for Nuclear Safety and Security, Joint Research Centre, Karlsruhe (Germany)

    2017-08-28

    The reduction of U{sup VI} uranyl halides or amides with simple Ln{sup II} or U{sup III} salts forms highly symmetric, linear, oxo-bridged trinuclear U{sup V}/Ln{sup III}/U{sup V}, Ln{sup III}/U{sup IV}/Ln{sup III}, and U{sup IV}/U{sup IV}/U{sup IV} complexes or linear Ln{sup III}/U{sup V} polymers depending on the stoichiometry and solvent. The reactions can be tuned to give the products of one- or two-electron uranyl reduction. The reactivity and magnetism of these compounds are discussed in the context of using a series of strongly oxo-coupled homo- and heterometallic poly(f-block) chains to better understand fundamental electronic structure in the f-block. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Effect of A-TIG Welding Process on the Weld Attributes of Type 304LN and 316LN Stainless Steels

    Science.gov (United States)

    Vasudevan, M.

    2017-03-01

    The specific activated flux has been developed for enhancing the penetration performance of TIG welding process for autogenous welding of type 304LN and 316LN stainless steels through systematic study. Initially single-component fluxes were used to study their effect on depth of penetration and tensile properties. Then multi-component activated flux was developed which was found to produce a significant increase in penetration of 10-12 mm in single-pass TIG welding of type 304LN and 316LN stainless steels. The significant improvement in penetration achieved using the activated flux developed in the present work has been attributed to the constriction of the arc and as well as reversal of Marangoni flow in the molten weld pool. The use of activated flux has been found to overcome the variable weld penetration observed in 316LN stainless steel with TIG welds compared to that of the welds produced by conventional TIG welding on the contrary the transverse strength properties of the 304LN and 316LN stainless steel welds produced by A-TIG welding exceeded the minimum specified strength values of the base metals. Improvement in toughness values were observed in 316LN stainless steel produced by A-TIG welding due to refinement in the weld microstructure in the region close to the weld center. Thus, activated flux developed in the present work has greater potential for use during the TIG welding of structural components made of type 304LN and 316LN stainless steels.

  16. Four-shell polyoxometalates featuring high-nuclearity Ln{sub 26} clusters. Structural transformations of nanoclusters into frameworks triggered by transition-metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhong; Li, Xin-Xiong; Yang, Tao; Cai, Zhen-Wen; Zheng, Shou-Tian [State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fujian (China)

    2017-03-01

    A series of polyoxometalates (POMs) that incorporate the highest-nuclearity Ln clusters that have been observed in such structures to date (Ln{sub 26}, Ln=La and Ce) are described, which exhibit giant multishell configurations (Ln is contained in W{sub 6} is contained in Ln{sub 26} is contained in W{sub 100}). Their structures are remarkably different from known giant POMs that feature multiple Ln ions. In particular, the incorporated Ln-O clusters with a nuclearity of 26 are significantly larger than known high-nuclearity (≤10) Ln-O clusters in POM chemistry. Furthermore, they also contain the largest number of La and Ce centers for any POM reported to date and represent a new kind of rare giant POMs with more than 100 W atoms. Interestingly, the La{sub 26}-containing POM can undergo a single-crystal to single-crystal structural transformation in the presence of various transition-metal ions, such as Cu{sup 2+}, Co{sup 2+}, and Ni{sup 2+}, from an inorganic molecular nanocluster into an inorganic-organic hybrid extended framework that is built from POM building blocks with even higher-nuclearity La{sub 28} clusters bridged by transition-metal complexes. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Heptanuclear heterometallic [Cu6Ln] clusters: trapping lanthanides into copper cages with artificial amino acids.

    Science.gov (United States)

    Sopasis, George J; Canaj, Angelos B; Philippidis, Aggelos; Siczek, Milosz; Lis, Tadeusz; O'Brien, James R; Antonakis, Manolis M; Pergantis, Spiros A; Milios, Constantinos J

    2012-05-21

    Employment of the artificial amino acid 2-amino-isobutyric acid, aibH, in Cu(II) and Cu(II)/Ln(III) chemistry led to the isolation and characterization of 12 new heterometallic heptanuclear [Cu(6)Ln(aib)(6)(OH)(3)(OAc)(3)(NO(3))(3)] complexes consisting of trivalent lanthanide centers within a hexanuclear copper trigonal prism (aibH = 2-amino-butyric acid; Ln = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), and Yb (12)). Direct curent magnetic susceptibility studies have been carried out in the 5-300 K range for all complexes, revealing the different nature of the magnetic interactions between the 3d-4f metallic pairs: dominant antiferromagnetic interactions for the majority of the pairs and dominant ferromagnetic interactions for when the lanthanide center is Gd(III) and Dy(III). Furthermore, alternating current magnetic susceptibility studies reveal the possibility of single-molecule magnetism behavior for complexes 7 and 8. Finally, complexes 2, 5-8, 10, and 12 were analyzed using positive ion electrospray mass spectrometry (ES-MS), establishing the structural integrity of the heterometallic heptanuclear cage structure in acetonitrile.

  18. Catalytic Oligomerization of Terminal Alkynes by Lanthanide Carbyls (η5-C5Me5)2LnCH(SiMe3)2 (Ln = Y, La, Ce)

    NARCIS (Netherlands)

    Heeres, H.J.; Teuben, J.H.

    1991-01-01

    Lanthanide and group 3 carbyls Cp*2LnCH(SiMe3)2 (1, Ln = Y; 2, Ln = La; 3, Ln = Ce) are active catalyst precursors for the oligomerization of terminal alkynes HC≡CR (R = alkyl, aryl, SiMe3). The regioselectivity and the extent of oligomerization depend strongly on the lanthanide applied as well as

  19. To bend or not to bend: experimental and computational studies of structural preference in Ln(Tp(iPr)2)2 (Ln = Sm, Tm).

    Science.gov (United States)

    Momin, Aurélien; Carter, Lee; Yang, Yi; McDonald, Robert; Essafi Labouille, Stéphanie; Nief, François; Del Rosal, Iker; Sella, Andrea; Maron, Laurent; Takats, Josef

    2014-11-17

    The synthesis and characterization of Ln(Tp(iPr2))2 (Ln = Sm, 3Sm; Tm, 3Tm) are reported. While the simple (1)H NMR spectra of the compounds indicate a symmetrical solution structure, with equivalent pyrazolyl groups, the solid-state structure revealed an unexpected, "bent sandwich-like" geometry. By contrast, the structure of the less sterically congested Tm(Tp(Me2,4Et))2 (4) adopts the expected symmetrical structure with a linear B-Tm-B arrangement. Computational studies to investigate the origin of the unexpected bent structure of the former compounds indicate that steric repulsion between the isopropyl groups forces the Tp ligands apart and permits the development of unusual interligand C-H···N hydrogen-bonding interactions that help stabilize the structure. These results find support in the similar geometry of the Tm(III) analogue [Tm(Tp(iPr2))2]I, 3Tm(+), and confirm that the low symmetry is not the result of a metal-ligand interaction. The relevance of these results to the general question of the coordination geometry of MX2 and M(C5R5)2 (M = heavy alkaline earth and Ln(II), X = halide, and C5R5 = bulky persubstituted cyclopentadienyl) complexes and the importance of secondary H-bonding and nonbonding interactions on the structure are highlighted.

  20. Investigation of the structural properties of an extended series of lanthanide bis-hydroxychlorides Ln(OH)(2)Cl (Ln = Nd-Lu, except Pm and Sm).

    Science.gov (United States)

    Zehnder, Ralph A; Clark, David L; Scott, Brian L; Donohoe, Robert J; Palmer, Phillip D; Runde, Wolfgang H; Hobart, David E

    2010-06-07

    The trivalent lanthanide bis-hydroxychloride compounds, Ln(OH)(2)Cl, (Ln = Nd through Lu, with the exception of Pm and Sm) have been prepared by hydrothermal synthesis starting with LnCl(3).nH(2)O. These compounds were synthesized at temperatures not exceeding the melting point of the Teflon liners in the Parr autoclaves ( approximately 220 degrees C). The compounds obtained were characterized by single crystal X-ray diffraction analysis, diffuse reflectance, FT-IR, and FT-Raman spectroscopies. Most of the lanthanide(III) bis-hydroxychlorides are isostructural and generally crystallize in the monoclinic space group P2(1)/m. The bis-hydroxychlorides of the heavier lanthanide(III) atoms with smaller ionic radii also crystallize in the orthorhombic crystal system. Apparently hydrogen bonds between the OH groups and the Cl atoms connect the layers in the "c" direction. These H-bonds seem to be the driving force for the angle beta of the monoclinic complexes to decrease with decreasing ionic radius of the Ln(III) ion and also for tying the layers together more strongly. As a result of this behavior, the structure of the heavier 4f analogues significantly resembles that of their orthorhombic counterparts. The heavier lanthanide bis-hydroxychlorides preferentially crystallize in the orthorhombic modification. The IR absorbance and Raman frequencies of the hydroxide ligands correlate as a function of the central lanthanide(III) ionic radius. This observation is corroborated by X-ray diffraction (XRD) structural data. These compounds are quite insoluble in near-neutral and basic aqueous solutions, but soluble in acidic solutions. It is expected that the analogue actinide bis-hydroxychlorides exhibit similar behavior and that this may have important implications in the immobilization and safe disposal of nuclear waste.

  1. Influence of lead oxide addition on LnTiTaO6 (Ln = Ce, Pr and Nd ...

    Indian Academy of Sciences (India)

    Influence of lead oxide addition on LnTiTaO6 (Ln = Ce, Pr and Nd) microwave ceramics. H PADMA KUMAR†, J K THOMAS††, ANNAMMA JOHN and SAM SOLOMON. ∗. Department of Physics, St. John's College, Anchal 691 306, India. †Department of Physics, W.M.O. Arts and Science College, Wayanad 673 122, India.

  2. Thermoelectric properties of molybdenum oxides LnMo(8)O(14) (Ln = La, Ce, Pr, Nd and Sm)

    DEFF Research Database (Denmark)

    Xu, Jianxiao Jackie; Sonne, Monica; Pryds, Nini

    2010-01-01

    The series LnMo8O14 (Ln = La, Ce, Pr, Nd and Sm) containing bicapped Mo8 clusters was synthesized via solid state reaction at 1673 K. Oxides of this type were reported to be narrow gap semiconductors. Our Seebeck coefficient measurements show that some of these reduced molybdenum oxides exhibit...

  3. Synthesis and characterization of K{sub 2}Ln{sub 2/3}Ta{sub 2}O{sub 7}·nH{sub 2}O (Ln= La, Pr, Nd), layered tantalates photo catalysts for water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Valencia S, H.; Tavizon, G. [UNAM, Instituto de Quimica, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Pfeiffer, H. [UNAM, Instituto de Investigaciones en Materiales, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Acosta, D. [UNAM, Instituto de Fisica, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Negron M, A., E-mail: hvalencia@utp.edu.co [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

    2015-07-01

    Three compounds of the K{sub 2}Ln{sub 2/3}Ta{sub 2}O{sub 7} (Ln = La, Nd, Pr) cation-deficient Ruddlesden-Popper series were prepared by the Pechini (polymeric complex) method. The crystal structures of the hydrated form of these compounds were determined by Rietveld analysis of the X-ray power diffraction data and High Resolution Transmission Electron Microscopy (HRTEM). The samples were also analyzed to determine specific area (Bet), degree of hydration (Thermogravimetric analysis), and photo catalytic activity for hydrogen evolution from water and aqueous methanol solution. (Author)

  4. Small-Scale Metal-Based Syntheses of Lanthanide Iodide, Amide, and Cyclopentadienyl Complexes as Analogues for Transuranic Reactions.

    Science.gov (United States)

    Windorff, Cory J; Dumas, Megan T; Ziller, Joseph W; Gaunt, Andrew J; Kozimor, Stosh A; Evans, William J

    2017-10-02

    Small-scale reactions of the Pu analogues La, Ce, and Nd have been explored in order to optimize reaction conditions for milligram scale reactions of radioactive plutonium starting from the metal. Oxidation of these lanthanide metals with iodine in ether and pyridine has been studied, and LnI 3 (Et 2 O) x (1-Ln; x = 0.75-1.9) and LnI 3 (py) 4 (2-Ln; py = pyridine, NC 5 H 5 ) have been synthesized on scales ranging from 15 mg to 2 g. The THF adducts LnI 3 (THF) 4 (3-Ln) were synthesized by dissolving 1-Ln in THF. The viability of these small-scale samples as starting materials for amide and cyclopentadienyl f-element complexes was tested by reacting KN(SiMe 3 ) 2 , KCp' (Cp' = C 5 H 4 SiMe 3 ), KCp'' (Cp'' = C 5 H 3 (SiMe 3 ) 2 -1,3), and KC 5 Me 4 H with 1-Ln generated in situ. These reactions produced Ln[N(SiMe 3 ) 2 ] 3 (4-Ln), Cp' 3 Ln (5-Ln), Cp″ 3 Ln (6-Ln), and (C 5 Me 4 H) 3 Ln (7-Ln), respectively. Small-scale samples of Cp' 3 Ce (5-Ce) and Cp' 3 Nd (5-Nd) were reduced with potassium graphite (KC 8 ) in the presence of 2.2.2-cryptand to check the viability of generating the crystallographically characterizable Ln 2+ complexes [K(2.2.2-cryptand)][Cp' 3 Ln] (8-Ln; Ln = Ce, Nd).

  5. Magnetic properties of the layered oxypnictides (LnOMnAs (Ln = La, Ce, Pr, Nd

    Directory of Open Access Journals (Sweden)

    Morosawa Y.

    2014-07-01

    Full Text Available We have investigated the rare earth elements dependence on the magnetism to understand the contribution to physical properties of the 4f electrons of (LnOMnAs (Pn = La, Ce, Pr, Nd. (CeOMnAs, (PrOMnAs and (NdOMnAs shows the antiferromagnetic behaviors at low temperature. (CeOMnAs and (NdOMnAs have the magnetic anomalies around 34 K and 24 K, respectively. So, it is speculated that the anomalies depend on the Mn -Mn distance directly

  6. Evaluating the electronic structure of formal LnII ions in LnII(C5H4SiMe3)3 1– using XANES spectroscopy and DFT calculations† †Electronic supplementary information (ESI) available: The results from quantum chemical ab initio FEFF9.6 code calculations for LnII L3-edges from Ln(C5H4SiMe3)3 x– (Ln = Sm, Tm, Y; x = 0, 1) and second derivative analysis of the lanthanides are in the ESI.† Our branching ratio analysis, the PBE//TZP optimized ground-state geometrical xyz coordinates and XC//TZ2P (XC = PBE, BLYP, B3LYP, BHandHLYP), single-point calculated total bonding energies of Ln(C5H4SiMe3)3 1–/0 (Ln = Sm, Ho), and relative single-point energy difference in kcal mol–1 between 4f10 5d1 and 4f11 5d0 in HoII(C5H4SiMe3)3 1– from different functional results at the PBE//TZP optimized ground-state geometries are also included. See DOI: 10.1039/c7sc00825b Click here for additional data file.

    Science.gov (United States)

    Fieser, Megan E.; Ferrier, Maryline G.; Su, Jing; Cary, Samantha K.; Engle, Jonathan W.; Lezama Pacheco, Juan S.; Olson, Angela C.; Ryan, Austin J.; Stein, Benjamin W.; Wagner, Gregory L.; Woen, David H.; Vitova, Tonya

    2017-01-01

    The isolation of [K(2.2.2-cryptand)][Ln(C5H4SiMe3)3], formally containing LnII, for all lanthanides (excluding Pm) was surprising given that +2 oxidation states are typically regarded as inaccessible for most 4f-elements. Herein, X-ray absorption near-edge spectroscopy (XANES), ground-state density functional theory (DFT), and transition dipole moment calculations are used to investigate the possibility that Ln(C5H4SiMe3)3 1– (Ln = Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb and Lu) compounds represented molecular LnII complexes. Results from the ground-state DFT calculations were supported by additional calculations that utilized complete-active-space multi-configuration approach with second-order perturbation theoretical correction (CASPT2). Through comparisons with standards, Ln(C5H4SiMe3)3 1– (Ln = Sm, Tm, Yb, Lu, Y) are determined to contain 4f6 5d0 (SmII), 4f13 5d0 (TmII), 4f14 5d0 (YbII), 4f14 5d1 (LuII), and 4d1 (YII) electronic configurations. Additionally, our results suggest that Ln(C5H4SiMe3)3 1– (Ln = Pr, Nd, Gd, Tb, Dy, Ho, and Er) also contain LnII ions, but with 4fn 5d1 configurations (not 4fn+1 5d0). In these 4fn 5d1 complexes, the C 3h-symmetric ligand environment provides a highly shielded 5d-orbital of a′ symmetry that made the 4fn 5d1 electronic configurations lower in energy than the more typical 4fn+1 5d0 configuration. PMID:28989638

  7. High Specific Power Motors in LN2 and LH2

    Science.gov (United States)

    Brown, Gerald V.; Jansen, Ralph H.; Trudell, Jeffrey J.

    2007-01-01

    A switched reluctance motor has been operated in liquid nitrogen (LN2) with a power density as high as that reported for any motor or generator. The high performance stems from the low resistivity of Cu at LN2 temperature and from the geometry of the windings, the combination of which permits steady-state rms current density up to 7000 A/sq cm, about 10 times that possible in coils cooled by natural convection at room temperature. The Joule heating in the coils is conducted to the end turns for rejection to the LN2 bath. Minimal heat rejection occurs in the motor slots, preserving that region for conductor. In the end turns, the conductor layers are spaced to form a heat-exchanger-like structure that permits nucleate boiling over a large surface area. Although tests were performed in LN2 for convenience, this motor was designed as a prototype for use with liquid hydrogen (LH2) as the coolant. End-cooled coils would perform even better in LH2 because of further increases in copper electrical and thermal conductivities. Thermal analyses comparing LN2 and LH2 cooling are presented verifying that end-cooled coils in LH2 could be either much longer or could operate at higher current density without thermal runaway than in LN2.

  8. Syntheses, Structure, Magnetism, and Optical Properties of the Interlanthanide Sulfides delta-Ln2-xLuxS3 (Ln = Ce, Pr, Nd)

    Energy Technology Data Exchange (ETDEWEB)

    Booth, Corwin H; Jin, Geng Bang; Choi, Eun Sang; Guertin, Robert P.; Brooks, James S.; Bray, Travis H.; Booth, Corwin H.; Albrecht-Schmitt, Thomas E.

    2008-01-11

    {delta}-Ln{sub 2-x}LuxS{sub 3} (Ln = Ce, Pr, Nd; x = 0.67-0.71) compounds have been synthesized through the reaction of elemental rare earth metals and S using Sb{sub 2}S{sub 3} flux at 1000 C. These compounds are isotypic with CeTmS{sub 3}, which has a complex three-dimensional structure. It includes four larger Ln{sup 3+} sites in eight- and nine-coordinate environments, two disordered seven-coordinate Ln{sup 3+}/Lu{sup 3+} positions, and two six-coordinate Lu{sup 3+} ions. The structure is constructed from one-dimensional chains of LnSn (n = 6-9) polyhedra that extend along the b axis. These polyhedra share faces or edges with two neighbors within the chains, while in the [ac] plane they share edges and corners with other chains. Least square refinements gave rise to the formulas of {delta}-Ce{sub 1.30}Lu{sub 0.70}S{sub 3}, {delta}-Pr{sub 1.29}Lu{sub 0.71}S{sub 3} and {delta}-Nd{sub 1.33}Lu{sub 0.67}S{sub 3}, which are consistent with the EDX analysis and magnetic susceptibility data. {delta}-Ln{sub 2-x}LuxS{sub 3} (Ln = Ce, Pr, Nd; x = 0.67-0.71) show no evidence of magnetic ordering down to 5 K. Optical properties measurements show that the band gaps for {delta}-Ce{sub 1.30}Lu{sub 0.70}S{sub 3}, {delta}-Pr{sub 1.29}Lu{sub 0.71}S{sub 3}, and {delta}-Nd{sub 1.33}Lu{sub 0.67}S{sub 3} are 1.25 eV, 1.38 eV, and 1.50 eV, respectively. Crystallographic data: {delta}-Ce{sub 1.30}Lu{sub 0.70}S{sub 3}, monoclinic, space group P2{sub 1}/m, a = 11.0186(7), b = 3.9796(3), c = 21.6562(15) {angstrom}, {beta} = 101.6860(10), V = 929.93(11), Z = 8; {delta}-Pr{sub 1.29}Lu{sub 0.71}S{sub 3}, monoclinic, space group P2{sub 1}/m, a = 10.9623(10), b = 3.9497(4), c = 21.5165(19) {angstrom}, {beta} = 101.579(2), V = 912.66(15), Z = 8; {delta}-Nd{sub 1.33}Lu{sub 0.67}S{sub 3}, monoclinic, space group P2{sub 1}/m, a = 10.9553(7), b = 3.9419(3), c = 21.4920(15) {angstrom}, {beta} = 101.5080(10), V = 909.47(11), Z = 8.

  9. Mechanism of charge transfer/disproportionation in LnCu3Fe4O12 (Ln = lanthanides)

    Science.gov (United States)

    Rezaei, N.; Hansmann, P.; Bahramy, M. S.; Arita, R.

    2014-03-01

    The Fe-Cu intersite charge transfer and Fe charge disproportionation are interesting phenomena observed in some LnCu3Fe4O12 (Ln = lanthanides) compounds containing light and heavy Ln atoms, respectively. We show that a change in the spin state is responsible for the intersite charge transfer in the light Ln compounds. At the high-spin state, such systems prefer an unusual Cu d8 configuration, whereas at the low-spin state they retreat to the normal Cu d9 configuration through a charge transfer from Fe to the Cu 3dxy orbital. We find that the strength of the crystal-field splitting and the relative energy ordering between Cu 3dxy and Fe 3d states are the key parameters determining the intersite charge transfer (charge disproportionation) in light (heavy) Ln compounds. It is further proposed that the size of Ln affects the on-site interaction strength of Cu 3d states, leading to a strong modification of the Cu L3-edge spectrum, as observed by the x-ray-absorption spectroscopy.

  10. Humidity sensing properties of LnFeO3 nanofibers synthesized by electrospinning (Ln = Sm, Nd, La)

    Science.gov (United States)

    Zou, Hefeng; Zhang, Yong; Duan, Zaihua; Tong, Yexing; Peng, Jinfeng; Zheng, Xuejun

    2018-01-01

    LnFeO3 (Ln = Sm, Nd, La) nanofibers are synthesized via electrospinning and the humidity sensors based on LnFeO3 nanofibers are fabricated and measured at different relative humidity to investigate the humidity sensing properties. The optimal working frequency of LnFeO3 nanofibers humidity sensors are all 100 Hz at which the sensors are of good linearity and high response. Compared with other LnFeO3 nanofibers humidity sensors, SmFeO3 nanofibers humidity sensor shows the best sensitivity and the impedance variation is more than five orders of magnitude with the relative humidity changing from 11% to 95%. The response time is about 10 s and the impedance versus RH curve is of good linearity. (The linear correlation coefficient is 0.98.) The results indicate that the SmFeO3 nanofibers with low Ln–O binding energy exhibit the best humidity sensing properties compared with others. We expect that our work has a great significance for fabricating high-performance humidity sensors.

  11. DIMENSI METRIK GRAPH LOBSTER Ln (q;r

    Directory of Open Access Journals (Sweden)

    PANDE GDE DONY GUMILAR

    2013-05-01

    Full Text Available The metric dimension of connected graph G is the cardinality of minimum resolving set in graph G. In this research, we study how to find the metric dimension of lobster graph Ln (q;r. Lobster graph Ln (q;r is a regular lobster graph with vertices backbone on the main path, every backbone vertex is connected to q hand vertices and every hand vertex is connected to r finger vertices, with n, q, r element of N. We obtain the metric dimension of lobster graph L2 (1;1 is 1, the metric dimension of lobster graph L2 (1;1 for n > 2 is 2.

  12. Three Novel Lanthanide Metal-Organic Frameworks (Ln-MOFs) Constructed by Unsymmetrical Aromatic Dicarboxylatic Tectonics: Synthesis, Crystal Structures and Luminescent Properties

    OpenAIRE

    Ya-Pan Wu; Dong-Sheng Li; Wei Xia; Sha-Sha Guo; Wen-Wen Dong

    2014-01-01

    Three novel Ln(III)-based coordination polymers, {[Ln2 (2,4-bpda)3 (H2O)x]·yH2O}n (Ln = La (III) (1), x = 2, y = 0, Ce (III) (2), Pr (III) (3), x = 4, y = 1) (2,4-H2bpda = benzophenone-2,4-dicarboxylic acid) have been prepared via a solvothermal method and characterized by elemental analysis, IR, and single-crystal X-ray diffraction techniques. Complex 1 exhibits a 3D complicated framework with a new 2-nodal (3,7)-connected (42·5) (44·51·66·8) topology. Complexes 2 and 3 are isomorphous, an...

  13. Multinuclear heterometallic (Y or Ln, Ba, Cu)-containing acetylacetonates as starting compounds for preparing the high-T{sub c} superconductors LnBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Khoroshun, I.V.; Samus, N.M.; Gandzii, M.V.; Tsapkov, V.I.; Karyaev, E.V.; Kiosse, G.A.

    1994-05-01

    Multinuclear heterometallic (Y or Ln, Ba, Cu)-containing acetylacetonates having a stoichiometric ratio between the cations Cu:Ba:Ln = 3:2:1 have been synthesized. The complexes are individual compounds and form an isostructural series with Ln = Y, La, Nd, Sm, Gd, Tb, Dy, Ho, Yb. The powder diffraction patterns have been indexed in the framework of the tetragonal system with the subcell parameters a{sub sub} = 11.48 and c{sub sub} = 9.37 {angstrom}. Conclusions regarding the multinuclear structure of the complexes, which contain exchange-coupled copper(II) ions, acetylacetonate ions performing the role of bidentate chelating ligands, and bridging alkoxo groups, have been drawn on the basis of data from magnetochemistry, as well as IR and ESR spectroscopy. All the compounds investigated are characterized by an identical pattern of thermal transformations in the 20-500{degrees}C range. The phase composition of the pyrolysis products of the complexes obtained in different stages of heating up to 1000{degrees}C has been investigated by X-ray diffraction analysis, and it has been shown that the final substances are practically phase-pure ternary oxides with a structure of the YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} type.

  14. Hra ve virtuální realitě

    OpenAIRE

    Čeleďa, Jan

    2017-01-01

    V posledních letech zaznamenaly headsety pro virtuální realitu značný posun kupředu jakz hlediska dostupnosti pro širší veřejnost, tak z hlediska inovací, které vývoj v oblastivirtuální reality přinesl. Nové technologie přináší mnoho změn a vylepšení v manipulaciuživatele s virtuálním světem, kvalitnější obraz a vhodnější napájení. Cílem této prácebylo vytvoření akční hry ve virtuální realitě. Jedná o simulaci lovu kachen dvouhlavňovoubrokovnicí v prostředí venkova. Při tvorbě práce byl klade...

  15. Trap Depth Engineering of SrSi2O2N2:Ln2+,Ln3+(Ln2+= Yb, Eu; Ln3+= Dy, Ho, Er) Persistent Luminescence Materials for Information Storage Applications.

    Science.gov (United States)

    Zhuang, Yixi; Lv, Ying; Wang, Le; Chen, Wenwei; Zhou, Tian-Liang; Takeda, Takashi; Hirosaki, Naoto; Xie, Rong-Jun

    2018-01-17

    Deep-trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with deep traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel deep-trap persistent luminescence materials in the Ln 2+ /Ln 3+ -doped SrSi 2 O 2 N 2 system (Ln 2+ = Yb, Eu; Ln 3+ = Dy, Ho, Er) by applying the strategy of trap depth engineering. Interestingly, the trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSi 2 O 2 N 2 :Yb,Dy and green-emitting SrSi 2 O 2 N 2 :Eu,Dy phosphors are demonstrated to be good candidates of information storage materials, which are attributed to their deep traps, narrow thermoluminescence glow bands, high emission efficiency, and excellent chemical stability. This work not only validates the suitability of deep-trap persistent luminescence materials in the information storage applications, but also broadens the avenue to explore such kinds of new materials for applications in anticounterfeiting and advanced displays.

  16. The Importance of Distance Education for ln-jobs Leamers

    Directory of Open Access Journals (Sweden)

    Nadja Dobnik

    2001-12-01

    Full Text Available In the area of professional training, new developments in technology offer numerous possibilities for distance education and autonomous learning. ln particular, programmes intended for knowledge, data and information acquisition are possible to draw up based on self­study of required material. However, for such professional training, different overall approach to programme contents outline and study materials design are necessary.

  17. Antiferromagnetic transitions of osmium-containing rare earth double perovskites Ba{sub 2}LnOsO{sub 6} (Ln=rare earths)

    Energy Technology Data Exchange (ETDEWEB)

    Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp; Doi, Yoshihiro; Wakeshima, Makoto

    2013-10-15

    The perovskite-type compounds containing both rare earth and osmium Ba{sub 2}LnOsO{sub 6} (Ln=Pr, Nd, Sm–Lu) have been prepared. Powder X-ray diffraction measurements and Rietveld analysis show that Ln{sup 3+} and Os{sup 5+} ions are structurally ordered at the M site of the perovskite BaMO{sub 3}. Magnetic susceptibility and specific heat measurements show that an antiferromagnetic ordering of Os{sup 5+} ions has been observed for Ba{sub 2}LnOsO{sub 6} (Ln=Pr, Nd, Sm, Eu, Gd, Lu) at 65–71 K. Magnetic ordering of Ln{sup 3+} moments occurs when the temperature is furthermore decreased. - Graphical abstract: The perovskite-type compounds containing both rare earth and osmium Ba{sub 2}LnOsO{sub 6} (Ln=Pr, Nd, Sm–Lu) have been prepared. An antiferromagnetic ordering of Os{sup 5+} ions has been observed for Ba{sub 2}LnOsO{sub 6} (Ln=Pr, Nd, Sm, Eu, Gd, Lu) at 65–71 K. Measurements and analysis of the specific heat for Ba{sub 2}PrOsO{sub 6} show that magnetic ordering of the Pr{sup 3+} moments should have occurred at ∼20 K. Display Omitted.

  18. Electrophilic Ln(III) cations protected by C-F → Ln interactions and their coordination chemistry with weak σ- and π-donors.

    Science.gov (United States)

    Yin, Haolin; Lewis, Andrew J; Carroll, Patrick; Schelter, Eric J

    2013-07-15

    A homoleptic cerium(III) amide complex, Ce(NPh(F)2)3 (1-Ce) (Ph(F) = pentafluorophenyl), in an unusual pseudo-trigonal planar geometry featuring six C-F → Ce interactions was prepared. The C-F → Ln interactions in solution were evident by comparison of the (19)F NMR shifts for the paramagnetic 1-Ce with those of the 4f(0) lanthanum(III) analogue. Coordination of weak σ- and π-donors, including ethers and neutral arene molecules, was achieved by the reversible displacement of the weak C-F → Ce interactions. Computational studies on Ce(NPh(F)2)3 and Ce(NPh(F)2)3(η(6)-C6H3Me3) provide information on the F → Ce interactions and Ce-η(6)-arene bonding.

  19. Crystallographic and spectroscopic characterization of LnFeTeO{sub 6} (Ln = La, Pr, Nd, Sm) materials

    Energy Technology Data Exchange (ETDEWEB)

    Lavat, Araceli E. [Departamento de Ingenieria Quimica, Facultad de Ingenieria, Universidad Nacional del Centro de la Provincia de Buenos Aires, 7400 Olavarria (Argentina); Mercader, Roberto C. [Departamento de Fisica and Instituto IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Baran, Enrique J., E-mail: baran@quimica.unlp.edu.a [Centro de Quimica Inorganica (CEQUINOR/CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C. Correo 962, 1900 La Plata (Argentina)

    2010-10-15

    Research highlights: {yields} LnFeTeO{sub 6} (Ln = La, Pr, Nd, Sm) materials belong to a PbSb{sub 2}O{sub 6} superstructure. {yields} IR and Raman spectra are dominated by TeO{sub 6} vibrations. {yields} Te-O bonds are relatively weak.{yields} Fe{sup III}O{sub 6}-polyhedra are scarcely distorted. - Abstract: Four mixed oxides of composition LnFeTeO{sub 6} (with Ln = La, Pr, Nd, Sm), belonging to a superstructure of the PbSb{sub 2}O{sub 6} structural type, have been prepared by solid state reactions and their unit cell parameters determined by X-ray powder diffractometry. The infrared and Raman spectra of these materials were also recorded and briefly discussed, on the basis of a site-symmetry analysis. The {sup 57}Fe-Moessbauer spectra show that the Fe{sup III}O{sub 6} octahedra present in these materials are not greatly distorted.

  20. Two isostructural 3D lanthanide coordination networks (Ln = Gd(3+), Dy(3+)) with squashed cuboid-type nanoscopic cages showing significant cryogenic magnetic refrigeration and slow magnetic relaxation.

    Science.gov (United States)

    Biswas, Soumava; Jena, Himanshu Sekhar; Adhikary, Amit; Konar, Sanjit

    2014-04-21

    Two isostructural lanthanide-based 3D coordination networks [Ln = Gd(3+) (1), Dy(3+)(2)] with densely packed distorted cuboid nanoscopic cages are reported for the first time. Magnetic characterization reveals that complex 1 shows a significant cryogenic magnetocaloric effect (-ΔSm = 44 J kg(-1) K(-1)), whereas 2 shows slow relaxation of magnetization.

  1. Photoelectron spectra of the late rare-earth misfit layer compounds (LnS)(1+x)TS2 (Ln=Tb, Dy, Ho; T=Nb, Ta)

    NARCIS (Netherlands)

    Fang, CM; Wiegers, GA; Haas, C

    Photoemission spectra (XPS and UPS) are presented for the valence band of misfit layer compounds (LnS)(1+x)TS2 with Ln = Dy, Ho or Tb; T = Nb or Ta. The Nb 4d(x)2 (or Ta 5d(x)2) conduction band is almost filled, which indicates a charge transfer of slightly less than one electron per T from the LnS

  2. Heterometallic Zn3Ln3Ensembles Containing (μ6-CO3) Ligand and Triangular Disposition of Ln3+ions: Analysis of Single-Molecule Toroic (SMT) and Single-Molecule Magnet (SMM) Behavior.

    Science.gov (United States)

    Goura, Joydeb; Colacio, Enrique; Herrera, Juan Manuel; Suturina, Elizaveta A; Kuprov, Ilya; Lan, Yanhua; Wernsdorfer, Wolfgang; Chandrasekhar, Vadapalli

    2017-11-21

    Two new heterometallic Zn 3 Ln 3 (Ln 3+ =Dy, Tb) complexes, with a double triangular topology of the metal ions, have been assembled from the polytopic Mannich base ligand 6,6'-{[2-(dimethylamino)ethylazanediyl]bis(methylene)}bis(2-methoxy-4-methylphenol) (H 2 L) with the aid of an in situ generated carbonate ligand from atmospheric CO 2 fixation. Theoretical calculations indicate axial ground states for the Ln 3+ ions in these complexes, with their local magnetic moments being almost coplanar and tangential to the Ln 3+ atoms that define the equilateral triangle. Therefore, they can be considered as single-molecule toroics (SMTs) with almost zero total magnetic moment. Micro-SQUID measurements on the Dy 3+ counterpart show hysteresis loops below 3 K that have an S-shape, with large coercive fields opening upon cooling. This behavior is typical of a single molecule magnet (SMM) with very slow zero-field relaxation. At around ±0.35 T, the loops have a broad step, which is due to a direct relaxation process and corresponds to an acceleration of the relaxation of the magnetization, also observed at this magnetic field from ac susceptibility measurements. Simulations suggest that the broad step corresponds to two level avoidance of crossing points where the spin chiral Kramers doublet meets excited states of the coupled manifold, whose position is defined by exchange and dipole interactions. The Tb 3+ counterpart does not exhibit SMM behavior, which is due to the fact that the degeneracy of the ground state of the exchange coupled system is lifted at zero field, thus favoring quantum tunneling of magnetization (QTM). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Ln{sub 12}-containing 60-tungstogermanates. Synthesis, structure, luminescence, and magnetic studies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kai-Yao; Lin, Zhengguo; Roemer, Isabella; Kortz, Ulrich [Jacobs University, Department of Life Sciences and Chemistry, Bremen (Germany); Bassil, Bassem S. [Jacobs University, Department of Life Sciences and Chemistry, Bremen (Germany); Department of Chemistry, Faculty of Sciences, University of Balamand, Tripoli (Lebanon); Vanhaecht, Stef; Parac-Vogt, Tatjana N. [Department of Chemistry, KU Leuven (Belgium); Saenz de Pipaon, Cristina [Institute of Chemical Research of Catalonia (ICIQ), Tarragona (Spain); Galan-Mascaros, Jose Ramon [Institute of Chemical Research of Catalonia (ICIQ), Tarragona (Spain); Catalan Institution for Research and Advanced Studies (ICREA), Barcelona (Spain); Fan, Linyuan; Cao, Jie [Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion Materials, School of Chemistry, Beijing Institute of Technology (China)

    2015-12-07

    A new class of hexameric Ln{sub 12}-containing 60-tungstogermanates, [Na(H{sub 2}O){sub 6} is contained in Eu{sub 12}(OH){sub 12}(H{sub 2}O){sub 18}Ge{sub 2}(GeW{sub 10}O{sub 38}){sub 6}]{sup 39-} (Eu{sub 12}), [Na(H{sub 2}O){sub 6} is contained in Gd{sub 12}(OH){sub 6}(H{sub 2}O){sub 24}Ge(GeW{sub 10}O{sub 38}){sub 6}]{sup 37-} (Gd{sub 12}), and [(H{sub 2}O){sub 6} is contained in Dy{sub 12}(H{sub 2}O){sub 24}(GeW{sub 10}O{sub 38}){sub 6}]{sup 36-} (Dy{sub 12}), comprising six di-Ln-embedded {β(4,11)-GeW_1_0} subunits was prepared by reaction of [α-GeW{sub 9}O{sub 34}]{sup 10-} with Ln{sup III} ions in weakly acidic (pH 5) aqueous medium. Depending on the size of the Ln{sup III} ion, the assemblies feature selective capture of two (for Eu{sub 12}), one (for Gd{sub 12}), or zero (for Dy{sub 12}) extra Ge{sup IV} ions. The selective encapsulation of a cationic sodium hexaaqua complex [Na(H{sub 2}O){sub 6}]{sup +} was observed for Eu{sub 12} and Gd{sub 12}, whereas Dy{sub 12} incorporates a neutral, distorted-octahedral (H{sub 2}O){sub 6} cluster. The three compounds were characterized by single-crystal XRD, ESI-MS, photoluminescence, and magnetic studies. Dy{sub 12} was shown to be a single-molecule magnet. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. A comparative evaluation of low-cycle fatigue behavior of type 316LN base metal, 316 weld metal, and 316LN/316 weld joint

    Science.gov (United States)

    Valsan, M.; Sundararaman, D.; Rao, K. Bhanu Sankara; Mannan, S. L.

    1995-05-01

    A comparative evaluation of the low-cycle fatigue (LCF) behavior of type 316LN base metal, 316 weld metal, and 316LN/316 weld joints was carried out at 773 and 873 K. Total strain-controlled LCF tests were conducted at a constant strain rate of 3 × 10-3 s-1 with strain amplitudes in the range ±0.20 to ±1.0 pct. Weld pads with single V and double V configuration were prepared by the shielded metal-arc welding (SMAW) process using 316 electrodes for weld-metal and weld-joint specimens. Optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) of the untested and tested samples were carried out to elucidate the deformation and the fracture behavior. The cyclic stress response of the base metal shows a very rapid hardening to a maximum stress followed by a saturated stress response. Weld metal undergoes a relatively short initial hardening followed by a gradual softening regime. Weld joints exhibit an initial hardening and a subsequent softening regime at all strain amplitudes, except at low strain amplitudes where a saturation regime is noticed. The initial hardening observed in base metal has been attributed to interaction between dislocations and solute atoms/complexes and cyclic saturation to saturation in the number density of slip bands. From TEM, the cyclic softening in weld metal was ascribed to the annihilation of dislocations during LCF. Type 316LN base metal exhibits better fatigue resistance than weld metal at 773 K, whereas the reverse holds true at 873 K. The weld joint shows the lowest life at both temperatures. The better fatigue resistance of weld metal is related to the brittle transformed delta ferrite structure and the high density of dislocations at the interface, which inhibits the growth rate of cracks by deflecting the crack path. The lower fatigue endurance of the weld joint was ascribed to the shortening of the crack initiation phase caused by surface intergranular crack initiation and to the poor

  5. Complexity

    Indian Academy of Sciences (India)

    Rahul Pandit

    2008-10-31

    Oct 31, 2008 ... ”The more complex a thing is, the more you can talk about it.” - attributed to Giorgio Parisi. ▻ ”C'est magnifique, mais ce n'est pas de la science.” (It is magnificent, but not all of it is science.) - attributed ... Earliest examples: theoretical computer science, algorithmic complexity, etc. ▻ Rapid progress after the ...

  6. LN2 Dewar 42 Delivery Overfill Inlet Solution

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; Mulholland, G.T.; /Fermilab

    1991-02-26

    Pressure vessels must be protected against overpressure scenarios. A scenario of particular concern is that from a high pressure LN2 pump, now standard on LN2 delivery trailers. A safety mechanism must be in place to prevent the overfilling, and subsequent overpressure from occurring because these pumps have a higher mass flow output than reasonably sized relief valves provide. The original solution to the problem was to close a valve on the fill line when a certain liquid level in the dewar is reached. The valve remains closed until the level drops below that threshold. The trigger level was about 13,000 gallons for the 20,000 gallon capacity dewar. The solution was in place from 1989 until present, 2004.

  7. Effect of crystalline electric field on heat capacity of LnBaCuFeO5 (Ln = Gd, Ho, Yb)

    Science.gov (United States)

    Lal, Surender; Mukherjee, K.; Yadav, C. S.

    2018-02-01

    Structural, magnetic and thermodynamic properties of layered perovskite compounds LnBaCuFeO5 (Ln = Ho, Gd, Yb) have been investigated. Unlike the iso-structural compound YBaCuFeO5, which shows commensurate antiferromagnetic to incommensurate antiferromagnetic ordering below ∼200 K, the studied compounds do not show any magnetic transition in measured temperature range of 2-350 K. The high temperature heat capacity of the compounds is understood by employing contributions from both optical and acoustic phonons. At low temperature, the observed upturn in the heat capacity is attributed to the Schottky anomaly. The magnetic field dependent heat capacity shows the variation in position of the anomaly with temperature, which appears due to the removal of ground state degeneracy of the rare earth ions, by the crystalline electric field.

  8. Structural chemistry and magnetic properties of LnMnFeGe4O12 (Ln = Y, Eu, Lu)

    Science.gov (United States)

    Xu, Diming; Avdeev, Maxim; Battle, Peter D.; Cadogan, J. M.; Lamont, Henry

    2017-10-01

    Polycrystalline samples of LnMnFeGe4O12 (Ln = Y, Eu, Lu) have been prepared using the ceramic method and characterised by a combination of magnetometry, Mössbauer spectroscopy, X-ray diffraction and neutron diffraction. They all adopt the space group P4/nbm with a 9.670, c 4.81 Å and show long-range antiferromagnetic order with transition temperatures 15 ≤ TN/K ≤ 17. The magnetic structure is the same in each case and consists of an A-type ordering of (001) planes; the ordered spins lie in the (001) plane. Comparison with isostructural compounds leads to the conclusion that subtle structural changes play a greater role than the electronic configuration of the cation in determining the magnetic structure.

  9. Synthesis and photoluminescence properties of GdBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Hongzhi [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun 130000 (China); College of Physics, Jinlin University, Changchun 130000 (China); Feng, Shuo [School of Jet Propulsion, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, Ying [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jinlin University, Changchun 130000 (China); Gu, Yipeng; Zhou, Jing; Yang, Hang [State Key Laboratory of Superhard Materials, Jinlin University, Changchun 130000 (China); Feng, Guanlin [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun 130000 (China); College of Physics, Jinlin University, Changchun 130000 (China); Li, Liang [State Key Laboratory of Superhard Materials, Jinlin University, Changchun 130000 (China); Wang, Wenquan [College of Physics, Jinlin University, Changchun 130000 (China); Liu, Xiaoyang [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jinlin University, Changchun 130000 (China); Xu, Dapeng, E-mail: xudp@jlu.edu.cn [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun 130000 (China); College of Physics, Jinlin University, Changchun 130000 (China)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer GdBO{sub 3}:Ln{sup 3+} nanofibers were synthesized successfully by electrospinning. Black-Right-Pointing-Pointer The samples have the average diameter of 150 nm and the flexible morphology. Black-Right-Pointing-Pointer The GdBO{sub 3}: Eu{sup 3+} nanofibers have the stronger orange emission. Black-Right-Pointing-Pointer The luminescence properties are different from the reported bulk material. Black-Right-Pointing-Pointer We describe the energy transform process of GdBO{sub 3}:Ln{sup 3+} system. - Abstract: GdBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers were synthesized using electrospinning combined with heat treatment. The synthesized nanofibers were characterized by X-ray diffraction, Raman spectroscopy, field emission-scanning electron microscopy, thermogravimetric and differential thermal analyses, and photoluminescence. The experimental results show that the flexible synthesized nanofibers have an average diameter of approximately 150 nm. The nanofibers consist of crystalline grains with diameters of about 40 nm and have a vaterite-type structure of GdBO{sub 3}. The GdBO{sub 3}:Eu{sup 3+} nanofibers exhibit strong orange and weak red emissions with a low ratio of red to orange emission intensities, which is different from those of the reported bulk materials and nanoparticles. The luminescence properties of the synthesized GdBO{sub 3}:Tb{sup 3+} nanofibers are essentially consistent with those of the synthesized GdBO{sub 3}:Tb{sup 3+}powders by solid-state reaction.

  10. Thermal decomposition of Ln(C2H5CO2)3·H2O (Ln = Ho, Er, Tm and Yb)

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2012-01-01

    The thermal decomposition of Ho(III), Er(III), Tm(III) and Yb(III) propionate monohydrates in argon was studied by means of thermogravimetry (TG), differential thermal analysis (DTA), IR-spectroscopy and X-ray diffraction (XRD). Dehydration takes place around 90 °C. It is followed...... by the decomposition of the anhydrous propionates to Ln2O2CO3 (Ln = Ho, Er, Tm or Yb) with the evolution of CO2 and 3-pentanone (C2H5COC2H5) between 300 and 400 °C. The further decomposition of Ln2O2CO3 to the respective sesquioxides Ln2O3 is characterized by an intermediate plateau extending from approximately 500......–700 °C in the TG traces. This stage corresponds to an overall composition of Ln2O2.5(CO3)0.5 but is more probably a mixture of Ln2O2CO3 and Ln2O3. The stability of this intermediate state decreases for the lighter rare-earth (RE) compounds studied. Full conversion to Ln2O3 is achieved at about 1,100 °C...

  11. KCa4(BO33:Ln3+ (Ln = Dy, Eu, Tb phosphors for near UV excited white–light–emitting diodes

    Directory of Open Access Journals (Sweden)

    Allu Amarnath Reddy

    2013-02-01

    Full Text Available A series of doped KCa4(BO33:Ln3+ (Ln: Dy, Eu and Tb compositions were synthesized by solid–state reaction method and their photoluminescent properties were systematically investigated to ascertain their suitability for application in white light emitting diodes. The X–ray diffraction (XRD and nuclear magnetic resonance (MAS–NMR data indicates that Ln3+–ions are successfully occupied the non–centrosymmetric Ca2+ sites, in the orthorhombic crystalline phase of KCa4(BO33 having space group Ama2, without affecting the boron chemical environment. The present phosphor systems could be efficiently excitable at the broad UV wavelength region, from 250 to 350 nm, compatible to the most commonly available UV light–emitting diode (LED chips. Photoluminescence studies revealed optimal near white–light emission for KCa4(BO33 with 5 wt.% Dy3+ doping, while warm white–light (CIE; X = 0.353, Y = 0.369 is obtained at 1wt.% Dy3+ ion concentration. The principle of energy transfer between Eu3+ and Tb3+ also demonstrates the potential white–light from KCa4(BO33:Eu3+,Tb3+ phosphor. Whereas, single Tb3+ and Eu3+–doped systems showed bright green (Tb3+ and red (Eu3+ emissions, respectively. Having structural flexibility along with remarkable chemical/thermal stability and suitable quantum efficiency these phosphors can be promising candidates as white–light–emitter for near UV LEDs.

  12. The single crystal structure determination of Ln{sub 6}MnSb{sub 15} (Ln=La, Ce), Ln{sub 6}Mn{sub 1-x}Zn{sub x}Sb{sub 15} (x∝0.5), and Ln{sub 6}ZnSb{sub 15} (Ln=La-Pr)

    Energy Technology Data Exchange (ETDEWEB)

    Benavides, Katherine A.; McCandless, Gregory T.; Chan, Julia Y. [Texas Univ., Dallas, Richardson, TX (United States). Dept. of Chemistry and Biochemistry

    2017-09-01

    Single crystals of Ln{sub 6}MnSb{sub 15} (Ln=La, Ce), Ln{sub 6}Mn{sub 1-x}Zn{sub x}Sb{sub 15} (x∝0.5), and Ln{sub 6}ZnSb{sub 15} (Ln=La-Pr) have been successfully grown and the compounds adopt the orthorhombic Ln{sub 6}MnSb{sub 15} structure type (space group Immm), with a∝4.3 Aa, b∝15 Aa, and c∝19 Aa. This structure is comprised of antimony nets and antimony ribbons which exhibit positional disorder at connecting points between antimony substructures, in addition to two partially occupied transition metal sites. The unit cell volumes of the La analogs displayed a systematic decrease upon Zn substitution. However, for the Ce{sub 6}Mn{sub 1-x}Zn{sub x}Sb{sub 15} and Pr{sub 6}Mn{sub 1-x}Zn{sub x}Sb{sub 15} (x∝0.5), the volumes deviate from linearity as observed in the parent compounds.

  13. Synthesis, structure, and magnetic properties of a new family of tetra-nuclear {Mn2(III)Ln2}(Ln = Dy, Gd, Tb, Ho) clusters with an arch-type topology: single-molecule magnetism behavior in the dysprosium and terbium analogues.

    Science.gov (United States)

    Chandrasekhar, Vadapalli; Bag, Prasenjit; Speldrich, Manfred; van Leusen, Jan; Kögerler, Paul

    2013-05-06

    Sequential reaction of Mn(II) and lanthanide(III) salts with a new multidentate ligand, 2,2'-(2-hydroxy-3-methoxy-5-methylbenzylazanediyl)diethanol (LH3), containing two flexible ethanolic arms, one phenolic oxygen, and a methoxy group afforded heterometallic tetranuclear complexes [Mn2Dy2(LH)4(μ-OAc)2](NO3)2·2CH3OH·3H2O (1), [Mn2Gd2(LH)4(μ-OAc)2](NO3)2·2CH3OH·3H2O (2), [Mn2Tb2(LH)4(μ-OAc)2](NO3)2·2H2O·2CH3OH·Et2O (3), and [Mn2Ho2(LH)4(μ-OAc)2]Cl2·5CH3OH (4). All of these dicationic complexes possess an arch-like structural topology containing a central Mn(III)-Ln-Ln-Mn(III) core. The two central lanthanide ions are connected via two phenolate oxygen atoms. The remaining ligand manifold assists in linking the central lanthanide ions with the peripheral Mn(III) ions. Four doubly deprotonated LH(2-) chelating ligands are involved in stabilizing the tetranuclear assembly. A magnetochemical analysis reveals that single-ion effects dominate the observed susceptibility data for all compounds, with comparably weak Ln···Ln and very weak Ln···Mn(III) couplings. The axial, approximately square-antiprismatic coordination environment of the Ln(3+) ions in 1-4 causes pronounced zero-field splitting for Tb(3+), Dy(3+), and Ho(3+). For 1 and 3, the onset of a slowing down of the magnetic relaxation was observed at temperatures below approximately 5 K (1) and 13 K (3) in frequency-dependent alternating current (AC) susceptibility measurements, yielding effective relaxation energy barriers of ΔE = 16.8 cm(-1) (1) and 33.8 cm(-1) (3).

  14. Interactions of Trivalent Lanthanide Cations with a New Hexadentate Di-Schiff Base: New Lanthanide(III) Complexes from (NE,N'E)-2,2'-(ethane-1,2-diylbis(oxy))bis(N-(pyridin-2-ylmethylene)ethanamine)

    National Research Council Canada - National Science Library

    Tsiouri, Mantha; Skorda, Konstantina; Papadimitriou, Christos; Li, Yang; Woollins, J Derek; Plakatouras, John C

    2010-01-01

    The novel lanthanide(III) complexes [Ln(NO(3))(2)L](NO(3)).3MeOH (Ln = La 1, Pr 2) and [Ln(NO(3))(3)L](NO(3)).2MeOH (Ln = Gd 3, Yb 4), where L = (NE,N'E)-2,2'-(ethane-1,2-diylbis(oxy))bis(N-(pyridin-2-ylmethylene...

  15. Preparation and electronmicroscopic investigation of new compounds Ln{sub 3}MO{sub 4}Cl{sub 5} (Ln=La-Nd; M=Ge,V); Darstellung und elektronenmikroskopische Untersuchung neuer Verbindungen des Typs Ln{sub 3}MO{sub 4}Cl{sub 5} (Ln=La-Nd; M=Ge,V)

    Energy Technology Data Exchange (ETDEWEB)

    Behler, B. [Giessen Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Lang, K. [Giessen Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Gruehn, R. [Giessen Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    1996-12-01

    By heating mixtures of LnOCl, LnCl{sub 3} und GeO{sub 2} (2 : 1 : 1) in evacuated silica tubes (Pt-shells inside) the compounds Ln{sub 3}GeO{sub 4}Cl{sub 5} (Ln = La-Nd) were prepared. The case that the temperature of preparation (La: T = 900 C, 8 d; Ce: T = 800 C, 9 d; Pr, Nd: T = 650 C, 13 d) had to be reduced from Ln = La to Ln = Nd indicates a decreasing thermodynamic stability in this direction. The compound La{sub 3}VO{sub 4}Cl{sub 5} was prepared by heating (900 C, 8 d) a mixture (2 : 1 : 1) of LaOCl, LaCl{sub 3} and VO{sub 2} and was investigated by electronmicroscopic techniques. (orig.)

  16. Facile synthesis and enhanced near infrared luminescent properties of CaWO4:Ln3+/Na+ (Ln = Nd, Er, and Yb) core/shell microstructure.

    Science.gov (United States)

    Su, Yiguo; Han, Dan; Du, Chunfang; Peng, Liman; Lv, Li; Wang, Xiaojing

    2014-05-01

    In this work, we reported the fabrication and characterization of CaWO4:Ln3+/Na+ (Ln = Nd, Er, and Yb) core/shell microspheres via a facile hydrothermal method in the presence of citric acid and PVP. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectra, and photoluminescence. It's found that citric acid could modulate the nucleation and growth of CaWO4 nanocrystals and enable the co-incorporation of Na+ and Ln3+ (Ln = Nd, Er, and Yb) into CaWO4 lattice. Meanwhile, PVP controlled the assembly of CaWO4 nanocrystals into a core/shell spherical structure. All CaWO4:Ln3+/Na+ (Ln = Nd, Er, and Yb) core/shell microspheres exhibited intense near-IR luminescence. In comparison with CaWO4:Ln3+/Na+ nanocrystals, the self-assembled core/shell nanoarchitechtures showed highly enhanced IR luminescent properties due to the depressing of surface energy-loss.

  17. Ab initio prediction of the electronic, magnetic and topological properties of Ln2O3 clusters.

    Science.gov (United States)

    Xia, Xiuli; Shao, Yuanzhi

    2017-07-05

    The structural, electronic and magnetic properties of the lanthanide oxide Ln2O3 clusters, where Ln signifies lanthanides from La to Lu, have been calculated using spin-polarized density functional theory with the B3LYP hybrid functional. The intensities of ferromagnetic RKKY interaction are found comparable with that of antiferromagnetic superexchange interaction in Ce2O3 / Pr2O3 / Nd2O3 / Gd2O3 / Tb2O3 / Tm2O3 clusters, while the other Ln2O3 clusters prefer ferromagnetic states to antiferromagnetic states in energy, except nonmagnetic La2O3 and Lu2O3 clusters. The theoretical spin magnetic moments, calculated three-dimensional spin density maps and dipole moments of Ln2O3 clusters suggest that the induced polarizations of oxygen atoms in Sm2O3, Eu2O3 and Yb2O3 clusters remarkably lead to the elongated Ln-O bond lengths in these clusters. The partial density of states of Ln2O3 clusters reveals that Sm3+ /Eu3+ /Yb3+ ions are distinctive from other Ln3+ ions in that their Ln-4f electrons are strongly hybrid with O-2 p electrons. The topological analysis of the electron density was also performed with quantum theory of atoms in molecules, which indicates the ionic Ln-O bonds have partial covalent characteristics.

  18. Ab initio prediction of the electronic, magnetic and topological properties of Ln2O3 clusters

    Science.gov (United States)

    Xia, Xiuli; Shao, Yuanzhi

    2017-07-01

    The structural, electronic and magnetic properties of the lanthanide oxide Ln2O3 clusters, where Ln signifies lanthanides from La to Lu, have been calculated using spin-polarized density functional theory with the B3LYP hybrid functional. The intensities of ferromagnetic RKKY interaction are found comparable with that of antiferromagnetic superexchange interaction in Ce2O3 / Pr2O3 / Nd2O3 / Gd2O3 / Tb2O3 / Tm2O3 clusters, while the other Ln2O3 clusters prefer ferromagnetic states to antiferromagnetic states in energy, except nonmagnetic La2O3 and Lu2O3 clusters. The theoretical spin magnetic moments, calculated three-dimensional spin density maps and dipole moments of Ln2O3 clusters suggest that the induced polarizations of oxygen atoms in Sm2O3, Eu2O3 and Yb2O3 clusters remarkably lead to the elongated Ln-O bond lengths in these clusters. The partial density of states of Ln2O3 clusters reveals that Sm3+ /Eu3+ /Yb3+ ions are distinctive from other Ln3+ ions in that their Ln-4f electrons are strongly hybrid with O-2 p electrons. The topological analysis of the electron density was also performed with quantum theory of atoms in molecules, which indicates the ionic Ln-O bonds have partial covalent characteristics.

  19. Prognosis of patients with pelvic lymph node (LN) metastasis after radical prostatectomy: value of extranodal extension and size of the largest LN metastasis.

    Science.gov (United States)

    Passoni, Niccolo M; Fajkovic, Harun; Xylinas, Evanguelos; Kluth, Luis; Seitz, Christian; Robinson, Brian D; Rouprêt, Morgan; Chun, Felix K; Lotan, Yair; Roehrborn, Claus G; Crivelli, Joseph J; Karakiewicz, Pierre I; Scherr, Douglas S; Rink, Michael; Graefen, Markus; Schramek, Paul; Briganti, Alberto; Montorsi, Francesco; Tewari, Ashutosh; Shariat, Shahrokh F

    2014-10-01

    To assess the prognostic role of extranodal extension (ENE) and the size of the largest lymph node (LN) metastasis in predicting early biochemical relapse (eBCR) in patients with LN metastasis after radical prostatectomy (RP). We evaluated BCR-free survival in men with LN metastases after RP and pelvic LN dissection performed in six high-volume centres. Multivariable Cox regression tested the role of ENE and diameter of largest LN metastasis in predicting eBCR after adjusting for clinicopathological variables. We compared the discrimination of multivariable models including ENE, the size of largest LN metastasis and the number of positive LNs. Overall, 484 patients were included. The median (interquartile range, IQR) follow-up was 16.1 (6-27.5) months. The median (IQR) number of removed LNs was 10 (4-14), and the median (IQR) number of positive LNs was 1 (1-2). ENE was present in 280 (58%) patients, and 211 (44%) had their largest metastasis >10 mm. Patients with ENE and/or largest metastasis of >10 mm had significantly worse eBCR-free survival (all P 2) and the diameter of LN metastasis (≤10 vs >10 mm), but not ENE, were significant predictors of eBCR (all P model (0.663) by 0.016 points. The diameter of the largest LN metastasis and the number of positive LNs are independent predictors of eBCR. Considered together, ENE and the diameter of the largest LN metastasis have less discrimination than the number of positive LNs. © 2013 The Authors. BJU International © 2013 BJU International.

  20. Structural trends in a series of isostructural lanthanide-copper metallacrown sulfates (Ln(III) = Pr, Nd, Sm, Eu, Gd, Dy and Ho): hexaaquapentakis[μ3-glycinehydroxamato(2-)]sulfatopentacopper(II)lanthanide(III) heptaaquapentakis[μ3-glycinehydroxamato(2-)]sulfatopentacopper(II)lanthanide(III) sulfate hexahydrate.

    Science.gov (United States)

    Pavlishchuk, Anna V; Kolotilov, Sergey V; Fritsky, Igor O; Zeller, Matthias; Addison, Anthony W; Hunter, Allen D

    2011-07-01

    The seven isostructural complexes, [Cu(5)Ln(C(2)H(4)N(2)O(2))(5)(SO(4))(H(2)O)(6.5)](2)(SO(4))·6H(2)O, where Ln(III) = Pr, Nd, Sm, Eu, Gd, Dy and Ho, are representatives of the 15-metallacrown-5 family. Each dianion of glycinehydroxamic acid (GlyHA) links two Cu(II) cations forming a cyclic [CuGlyHA](5) frame. The Ln(III) cations are located at the centre of the [CuGlyHA](5) rings and are bound by the five hydroxamate O atoms in the equatorial plane. Five water molecules are coordinated to Cu(II) cations, and one further water molecule, located close to an inversion centre between two adjacent [Cu(5)Ln(GlyHA)(5)](2+) cations, is disordered around this inversion centre and coordinated to a Cu(II) cation of either the first or second metallacrown ether. Another water molecule and one of the two crystallographically independent sulfate anions are coordinated, the latter in a bidentate fashion, to the Ln(III) cation in the axial positions. The second sulfate anion is not coordinated to the cation, but is located in an interstitial position on a crystallographic inversion centre, thus leading to disorder of the O atoms around the centre of inversion. The Ln-O bond distances follow the trend of the lanthanide contraction. The apical Ln-O bond distances are very close to the sums of the ionic radii. However, the Ln-O distances within the metallacrown units are slightly compressed and the Ln(III) cations protrude significantly from the plane of the otherwise flat metallacrown ligand, thus indicating that the cavity is somewhat too small to accommodate the Ln(III) ions comfortably. This effect decreases with the size of the lanthanide cation from complex (I) (Ln(III) = Pr; 0.459) to complex (VII) (Ln(III) = Ho; 0.422), which indicates that the smaller lanthanide cations fit the cavity of the pentacopper metallacrown ring better than the larger ones. The diminished contraction of Ln-O distances within the metallacrown planes leads to an aniostropic contraction of the unit

  1. A determination of the oxygen non-stoichiometry of the oxygen storage materials LnBaMn{sub 2}O{sub 5+δ} (Ln=Gd, Pr)

    Energy Technology Data Exchange (ETDEWEB)

    Jeamjumnunja, Kannika; Gong, Wenquan; Makarenko, Tatyana; Jacobson, Allan J., E-mail: ajjacob@uh.edu

    2016-07-15

    The A-site ordered double-perovskite oxides, LnBaMn{sub 2}O{sub 5+δ} (Ln=Gd, Pr), were synthesized and investigated to understand the effect of A site cation substitution on the oxygen storage properties of these materials. The present results are compared with our previous data for YBaMn{sub 2}O{sub 5+δ}. The results clearly reveal that changing the Ln cation strongly influences the oxidation/reduction behavior of LnBaMn{sub 2}O{sub 5+δ}. Based on thermogravimetric analysis data, oxygen uptake begins at lower temperatures in both air and oxygen in compounds with Ln{sup 3+} ions larger than Y{sup 3+}. These oxides exhibit almost complete and reversible oxygen uptake/release between fully-reduced LnBaMn{sub 2}O{sub 5} and fully-oxidized LnBaMn{sub 2}O{sub 6} during changes of the oxygen partial pressure between air and 1.99% H{sub 2}/Ar. In addition, the oxygen non-stoichiometries of GdBaMn{sub 2}O{sub 5+δ} and PrBaMn{sub 2}O{sub 5+δ} were determined as a function of pO{sub 2} at 600, 650, 700 and 750 °C by Coulometric titration at near-equilibrium conditions. The results confirm that these materials have two distinct phases on oxidation/reduction with δ≈0, 0.5 and a third phase with a range of composition with an oxygen content (5+δ) approaching ~6. The stabilities of the LnBaMn{sub 2}O{sub 5+δ} phases extend over a wide range of oxygen partial pressures (∼10{sup −25}≤pO{sub 2} (atm)≤∼1) depending on temperature. Isothermal experiments show that the larger the Ln{sup 3+} cation the lower pO{sub 2} for phase conversion. At some temperatures and pO{sub 2} conditions, the LnBaMn{sub 2}O{sub 5+δ} compounds are unstable with respect to decomposition to BaMnO{sub 3−δ} and LnMnO{sub 3}. This instability is more apparent in Coulometric titration experiments than in thermogravimetric analysis. The Coulometric titration experiments are necessarily slow in order to achieve equilibrium oxygen compositions. - Graphical abstract: Structure of Ln

  2. Microstructure, local mechanical properties and stress corrosion cracking susceptibility of an SA508-52M-316LN safe-end dissimilar metal weld joint by GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Hongliang; Zhu, Ruolin [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049 (China); Zhang, Zhiming [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Jianqiu, E-mail: wangjianqiu@imr.ac.cn [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Han, En.-Hou.; Ke, Wei [Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning KeyLaboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Su, Mingxing [Shanghai Research Center for Weld and Detection Engineering Technique of Nuclear Equipment, Shanghai 201306 (China)

    2016-07-04

    The microstructure, local mechanical properties and local stress corrosion cracking susceptibility of an SA508-52M-316LN domestic dissimilar metal welded safe-end joint used for AP1000 nuclear power plant prepared by automatic gas tungsten arc welding was studied in this work by optical microscopy, scanning electron microscopy (with electron back scattering diffraction and an energy dispersive X-ray spectroscopy system), micro-hardness testing, local mechanical tensile testing and local slow strain rate tests. The micro-hardness, local mechanical properties and stress corrosion cracking susceptibility across this dissimilar metal weld joint vary because of the complex microstructure across the fusion area and the dramatic chemical composition change across the fusion lines. Briefly, Type I boundaries and Type II boundaries exist in 52Mb near the SA508-52Mb interface, a microstructure transition was found in SA508 heat affected zone, the residual strain and grain boundary character distribution changes as a function of the distance from the fusion boundary in 316LN heat affected zone, micro-hardness distribution and local mechanical properties along the DMWJ are heterogeneous, and 52Mw-316LN interface has the highest SCC susceptibility in this DMWJ while 316LN base metal has the lowest one.

  3. Structure of X-ray photoelectron spectra of low-energy and core electrons of Ln(C6H4OCH3COO-3

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2005-01-01

    Full Text Available This paper deals with the results of an X-ray photo electron spectroscopy of lanthanide ortho-metoxybenzoates Ln(C6H4OCH3COO-3, where Ln represents lanthanides La through Lu except for Pm and C6H4OCH3COO- - residuum of ortho-metoxybenzoic acid. The core and outer electron X-ray photo electron spectroscopy spectra in the binding energy range of 0-1250 eV were shown to exhibit a complex, fine structure. The said structure was established due to the outer (0-15 eV binding energy and inner (15-50 eV binding energy valence molecular orbital from the filled Ln5p and O2s atomic shells multiple splitting, many-body perturbation, dynamic effect, etc. The mechanisms of such a fine structure formation were shown to manifest different probabilities in the spectrum of a certain electronic shell. There fore, the fine X-ray photo electron spectroscopy spectral structure resulting from a certain mechanism can be interpreted and its quantitative parameters related to the physical and chemical properties of the studied com pounds (degree of delocalization and participation of Ln4f electrons in the chemical bond, electronic configuration and oxidation states, density of uncoupled electrons on paramagnetic ions, degree of participation of the low binding energy filled electronic shells of lanthanide and ligands information of the outer and in nervalence molecular orbitals, lanthanide close environment structure in amorphous materials, etc.

  4. Neutron diffraction study of LnBaCuFeO5+#delta#, (Ln=Y,Pr)

    DEFF Research Database (Denmark)

    Ruiz-Aragón, M.J.; Amador, U.; Morán, E.

    1994-01-01

    Neutron diffraction studies of the title materials have been performed at 600K, R.T. and 8K. Copper and iron ions are randomly distributed in two equivalent MO2 planes being the symmetry P4/mmm for all the samples and temperatures. Some extra oxygen has been found in PrBaCuFeO5+δ destroying the AF...... ordering, present at R. T. in YBaCuFeO5. Besides this, at low temperature a magnetic phase transition has been found. On the other hand, both materials show a complex micro-structure as determined by electron diffraction....

  5. Three Novel Lanthanide Metal-Organic Frameworks (Ln-MOFs Constructed by Unsymmetrical Aromatic Dicarboxylatic Tectonics: Synthesis, Crystal Structures and Luminescent Properties

    Directory of Open Access Journals (Sweden)

    Ya-Pan Wu

    2014-09-01

    Full Text Available Three novel Ln(III-based coordination polymers, {[Ln2 (2,4-bpda3 (H2Ox]·yH2O}n (Ln = La (III (1, x = 2, y = 0, Ce (III (2, Pr (III (3, x = 4, y = 1 (2,4-H2bpda = benzophenone-2,4-dicarboxylic acid have been prepared via a solvothermal method and characterized by elemental analysis, IR, and single-crystal X-ray diffraction techniques. Complex 1 exhibits a 3D complicated framework with a new 2-nodal (3,7-connected (42·5 (44·51·66·8 topology. Complexes 2 and 3 are isomorphous, and feature a 3D 4-connected (65·8-CdSO4 network. Moreover, solid-state properties such as thermal stabilities and luminescent properties of 1 and 2 were also investigated. Complex 1 crystallized in a monoclinic space group P21/c with a = 14.800 (3, b = 14.500 (3, c = 18.800 (4 Å, β = 91.00 (3, V = 4033.9 (14 Å3 and Z = 4. Complex 2 crystallized in a monoclinic space group Cc with a = 13.5432 (4, b = 12.9981 (4, c = 25.7567 (11 Å, β = 104.028 (4, V = 1374.16 (7 Å3 and Z = 4.

  6. Three novel lanthanide metal-organic frameworks (Ln-MOFs) constructed by unsymmetrical aromatic dicarboxylatic tectonics: synthesis, crystal structures and luminescent properties.

    Science.gov (United States)

    Wu, Ya-Pan; Li, Dong-Sheng; Xia, Wei; Guo, Sha-Sha; Dong, Wen-Wen

    2014-09-11

    Three novel Ln(III)-based coordination polymers, {[Ln2 (2,4-bpda)3 (H2O)x]·yH2O}n (Ln = La (III) (1), x = 2, y = 0, Ce (III) (2), Pr (III) (3), x = 4, y = 1) (2,4-H2bpda = benzophenone-2,4-dicarboxylic acid) have been prepared via a solvothermal method and characterized by elemental analysis, IR, and single-crystal X-ray diffraction techniques. Complex 1 exhibits a 3D complicated framework with a new 2-nodal (3,7)-connected (42·5) (44·51·66·8) topology. Complexes 2 and 3 are isomorphous, and feature a 3D 4-connected (65·8)-CdSO4 network. Moreover, solid-state properties such as thermal stabilities and luminescent properties of 1 and 2 were also investigated. Complex 1 crystallized in a monoclinic space group P21/c with a = 14.800 (3), b = 14.500 (3), c = 18.800 (4) Å, β = 91.00 (3), V = 4033.9 (14) Å3 and Z = 4. Complex 2 crystallized in a monoclinic space group Cc with a = 13.5432 (4), b = 12.9981 (4), c = 25.7567 (11) Å, β = 104.028 (4), V = 1374.16 (7) Å3 and Z = 4.

  7. Formation enthalpies of LaLn'O3 (Ln'=Ho, Er, Tm and Yb) interlanthanide perovskites

    Science.gov (United States)

    Qi, Jianqi; Guo, Xiaofeng; Mielewczyk-Gryn, Aleksandra; Navrotsky, Alexandra

    2015-07-01

    High-temperature oxide melt solution calorimetry using 3Na2O·MoO3 at 802 °C was performed for interlanthanide perovskites LaLn'O3 (Ln'=Ho, Er, Tm and Yb) and lanthanide oxides (La2O3, Ho2O3, Er2O3, Tm2O3 and Yb2O3). The enthalpies of formation of these interlanthanide perovskites from binary lanthanide oxides at room temperature (25 °C) were determined to be -8.3±3.4 kJ/mol for LaHoO3, -9.9±3.0 kJ/mol for LaErO3, -10.8±2.7 kJ/mol for LaTmO3 and -12.3±2.9 kJ/mol for LaYbO3. There is a roughly linear relationships between these enthalpy values and the tolerance factor for these and for other LaM3+O3 (M=In, Sc, Ga, Al, Fe and Cr) perovskites, confirming that the distortion of the perovskites as results from ionic radius difference of A-site and B-site cations, is the main factor determining the stability of these compounds.

  8. Thermal decomposition of heavy rare-earth butanoates, Ln(C3H7CO2)3 (Ln = Er, Tm, Yb and Lu) in argon

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Yue, Zhao; Tang, Xiao

    2016-01-01

    was observed in all four compounds, but its course depends on the rare-earth element. Decomposition to sesquioxides proceeds via the formation of dioxymonocarbonates (Ln2O2CO3) and release of 4-heptanone (C3H7COC3H7) as well as carbon dioxide (CO2) without evidence for an intermediate oxobutanoate stage...... of Ln2O2CO3 and Ln2O3. The stability of this intermediate state seems to decrease with the mass of the rare-earth elements. Complete conversion to Ln2O3 is reached at about 1100 °C. The overall thermal decomposition behaviour of the title compounds is different from previous reports for other rare-earth...

  9. A new series of lanthanide coordination polymers with 2,2‧-bipyridine and glutaric acid: Synthesis, crystal structures and properties of [Ln(bipy)(glut)(NO3)

    Science.gov (United States)

    Wang, Chunguang; Xing, Yongheng; Li, Zhangpeng; Li, Jing; Zeng, Xiaoqing; Ge, Maofa; Niu, Shuyun

    2009-08-01

    A series of new lanthanide coordination polymers, with the formula [Ln(bipy)(glut)(NO 3)] (Ln = Eu ( 1), Tb ( 2), Sm ( 3), Pr ( 4); bipy = 2,2'-bipyridine; H 2glut = glutaric acid), have been synthesized under the hydrothermal condition and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analyses reveal that all four complexes are isostructural and crystallized in monoclinic system, P2 1/ c space group. For these complexes, the Ln 3+ are all linked through glutaric acid ligands to form 1D chain-like polymeric structures, and bipy and NO3- are coordinated on two sides of the chains. The thermogravimetric analysis of 1 and photoluminescent properties of 1 and 2 are discussed in detail.

  10. A determination of the oxygen non-stoichiometry of the oxygen storage materials LnBaMn2O5+δ (Ln=Gd, Pr)

    Science.gov (United States)

    Jeamjumnunja, Kannika; Gong, Wenquan; Makarenko, Tatyana; Jacobson, Allan J.

    2016-07-01

    The A-site ordered double-perovskite oxides, LnBaMn2O5+δ (Ln=Gd, Pr), were synthesized and investigated to understand the effect of A site cation substitution on the oxygen storage properties of these materials. The present results are compared with our previous data for YBaMn2O5+δ. The results clearly reveal that changing the Ln cation strongly influences the oxidation/reduction behavior of LnBaMn2O5+δ. Based on thermogravimetric analysis data, oxygen uptake begins at lower temperatures in both air and oxygen in compounds with Ln3+ ions larger than Y3+. These oxides exhibit almost complete and reversible oxygen uptake/release between fully-reduced LnBaMn2O5 and fully-oxidized LnBaMn2O6 during changes of the oxygen partial pressure between air and 1.99% H2/Ar. In addition, the oxygen non-stoichiometries of GdBaMn2O5+δ and PrBaMn2O5+δ were determined as a function of pO2 at 600, 650, 700 and 750 °C by Coulometric titration at near-equilibrium conditions. The results confirm that these materials have two distinct phases on oxidation/reduction with δ≈0, 0.5 and a third phase with a range of composition with an oxygen content (5+δ) approaching 6. The stabilities of the LnBaMn2O5+δ phases extend over a wide range of oxygen partial pressures (∼10-25≤pO2 (atm)≤∼1) depending on temperature. Isothermal experiments show that the larger the Ln3+ cation the lower pO2 for phase conversion. At some temperatures and pO2 conditions, the LnBaMn2O5+δ compounds are unstable with respect to decomposition to BaMnO3-δ and LnMnO3. This instability is more apparent in Coulometric titration experiments than in thermogravimetric analysis. The Coulometric titration experiments are necessarily slow in order to achieve equilibrium oxygen compositions.

  11. Structural anomalies associated with the electronic and spin transitions in LnCoO(3)

    NARCIS (Netherlands)

    Knizek, K; Jirak, Z; Hejtmanek, J; Veverka, M; Marysko, M; Maris, G; Palstra, TTM; Knížek, K.; Maryško, M.

    A powder X-ray diffraction study, combined with magnetic susceptibility and electric transport measurements, was performed on a series of LnCoO(3) perovskites (Ln = Y, Dy, Gd, Sm, Nd, Pr and La) over a temperature range 100-1000 K. A non-standard temperature dependence of the observed thermal

  12. Electrospinning synthesis and photoluminescence properties of one-dimensional LuBO{sub 3}:Ln{sup 3+} (Ln = Tb, Eu) nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Hongzhi [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun (China); Liu, Runru [College of Science, Changchun University, Changchun (China); Yang, Min [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jinlin University, Changchun (China); Zhou, Jing; Gu, Yipeng; Yang, Hang [State Key Laboratory of Superhard Materials, Jinlin University, Changchun (China); Wang, Wenquan [College of Physics, Jinlin University, Changchun (China); Xu, Dapeng [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun (China); College of Physics, Jinlin University, Changchun (China)

    2013-09-15

    LuBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers were synthesized via electrospinning combined with heat treatment. The structure analyses show that the as-prepared LuBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers have porous morphology and average diameters of 200-300 nm, which consist of closely lined nanoparticles with the size of about 30 nm. The fluorescence spectra show that the R/O values are 1.02 and 1.12 for LuBO{sub 3}:3 mol% Eu{sup 3+} nanofibers sintered at 800 and 900 C, respectively. For LuBO{sub 3}:xTb{sup 3+} (x = 1, 3, and 5 mol%) nanofibers, the emission intensities and the fluorescence lifetime increase slightly with increasing Tb{sup 3+} concentration. The fluorescence characteristic of LuBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers is discussed. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Structural and electrical properties of T′-type Ln{sub 2}CuO{sub 4} (Ln = Pr, Nd, Sm, Eu and Gd) ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Salame, Paresh Hiralal [Department of Applied Physics, Laxminarayan Institute of Technology, RTM Nagpur University, Nagpur, INDIA paresh.salame@gmail.com (India)

    2016-05-23

    T′-type Ln{sub 2}CuO{sub 4} (Ln = Pr, Nd, Sm, Eu and Gd) were successfully synthesized in phase pure form using conventional solid state reaction and sintering route. For all the Ln{sub 2}CuO{sub 4} samples, the solid state reaction temperature was found to be 950 °C and pure phase was realized only after 2-3 intermediate milling and solid state reaction cycles, irrespective of the lanthanide ion radius. Effect of lanthanide ion contraction on the structural properties was clearly revealed by the powder X-ray diffraction, with the XRD peaks observed to be shifting towards higher 2θ values with the decrease in Ln ionic radii. The optimum sintering temperature of these solid state reacted Ln{sub 2}CuO{sub 4} powder was found to be 1100 °C except for Pr{sub 2}CuO{sub 4} powder. The conductivity of these samples were tested over a wide temperature range (−100 to 150 °C), an anomaly was observed in the conductivity of all the Ln{sub 2}CuO{sub 4} samples near the antiferromagnetic ordering temperature of Cu (~ 30 °C), thus suggesting the bearing of ordering of magnetic moments on the electrical properties.

  14. Two novel 3d-4f heterometallic coordination polymers with infinite [Ln4(OH)4]n(8n+) chains involving in situ decarboxylation.

    Science.gov (United States)

    Wu, Wen-Ya; Zhang, Rui-Feng; Zhang, Xue-Jing; Cheng, Peng

    2015-04-28

    Two unique heterometallic {Ln4Co} coordination polymers with infinite Ln4(OH)4]n(8n+) chains have been successfully assembled, which represent the first example of heterometallic Ln-Co coordination polymers containing infinite lanthanide hydroxide chains.

  15. Pentanuclear heterometallic {Mn(III)(2)Ln(3)} (Ln = Gd, Dy, Tb, Ho) assemblies in an open-book type structural topology: appearance of slow relaxation of magnetization in the Dy(III) and Ho(III) analogues.

    Science.gov (United States)

    Bag, Prasenjit; Chakraborty, Amit; Rogez, Guillaume; Chandrasekhar, Vadapalli

    2014-07-07

    The reaction of Ln(III) nitrate and Mn(ClO4)2·6H2O salts in the presence of a multidentate sterically unencumbered ligand, (E)-2,2'-(2-hydroxy-3-((2-hydroxyphenylimino)methyl)-5-methylbenzylazanediyl)diethanol (LH4) leads to the isolation of four isostructural pentanuclear hetereometallic complexes [Mn(III)2Gd3(LH)4(NO3)(HOCH3)]ClO4·NO3 (1), [Mn(III)2Dy3(LH)4(NO3)(HOCH3)]ClO4·NO3 (2), [Mn(III)2Tb3(LH)4(NO3)(HOCH3)]ClO4·NO3 (3), and [Mn(III)2Ho3(LH)4(NO3)(HOCH3)]ClO4·NO3 (4) with an open-book type structural topology. 1-4 are dicationic and crystallize in the achiral space group, P21/n. A total of four triply deprotonated ligands, [LH](3-), are involved in holding the pentameric metal framework, {Mn(III)2Ln3}. In these complexes both the lanthanide and the manganese(III) ions are doubly bridged, involving phenolate or ethoxide oxygen atoms. The magnetochemical analysis reveals the presence of global antiferromagnetic interactions among the spin centers at low temperatures in all the four compounds. AC susceptibility measurements show the presence of temperature dependent out-of-phase ac signal for compounds 2 and 4 indicating an SMM behavior.

  16. Speciální aplikace VoIP

    OpenAIRE

    Lembard, Tomáš

    2011-01-01

    Cílem této diplomové práce je návrh a následná realizace zařízení pro přenos hlasu v lokální síti a popisem použitých obvodů a řešení po stránce hw i sw. Zabývá se problematikou digitalizace nízkofrekvenčních signálů, strukturou IP a UDP protokolů, implementací TCP/IP stacku cIPS The aim of this master's thesis is suggestion and following realization of voice transmission over the local network equipment and a description of used circuits and solutions in terms of hardware and software. Th...

  17. Synthesis and structural diversity of trivalent rare-earth metal diisopropylamide complexes.

    Science.gov (United States)

    Spallek, Tatiana; Heß, Oliver; Meermann-Zimmermann, Melanie; Meermann, Christian; Klimpel, Michael G; Estler, Frank; Schneider, David; Scherer, Wolfgang; Tafipolsky, Maxim; Törnroos, Karl W; Maichle-Mössmer, Cäcilia; Sirsch, Peter; Anwander, Reiner

    2016-09-21

    A series of rare-earth metal diisopropylamide complexes has been obtained via salt metathesis employing LnCl3(THF)x and lithium (LDA) or sodium diisopropylamide (NDA) in n-hexane. Reactions with AM : Ln ratios ≥3 gave ate complexes (AM)Ln(NiPr2)4(THF)n (n = 1, 2; Ln = Sc, Y, La, Lu; AM = Li, Na) in good yields. For smaller rare-earth metal centres such as scandium and lutetium, a Li : Ln ratio = 2.5 accomplished ate-free tris(amido) complexes Ln(NiPr2)3(THF). The chloro-bridged dimeric derivatives [Ln(NiPr2)2(μ-Cl)(THF)]2 (Ln = Sc, Y, La, Lu) could be obtained in high yields for Li : Ln = 1.6-2. The product resulting from the Li : La = 1 : 1.6 reaction revealed a crystal structure containing two different molecules in the crystal lattice, [La(NiPr2)2(THF)(μ-Cl)]2·La(NiPr2)3(THF)2. Recrystallization of the chloro-bridged dimers led to the formation of the monomeric species Ln(NiPr2)2Cl(THF)2 (Ln = Sc, Lu) and La(NiPr2)3(THF)2. The reaction of YCl3 and LDA with Li : Y = 2 in the absence of THF gave a bimetallic ate complex LiY(NiPr2)4 with a chain-like structure. For scandium, the equimolar reactions with LDA or NDA yielded crystals of tetrametallic mono(amido) species, {[Sc(NiPr2)Cl2(THF)]2(LiCl)}2 and [Sc(NiPr2)Cl2(THF)]4, respectively. Depending on the Ln(iii) size, AM, and presence of a donor solvent, ate complexes (AM)Ln(NiPr2)4(THF)n show distinct dynamic behaviour as revealed by variable temperature NMR spectroscopy. The presence of weak LnCH(iPr) β-agostic interactions, as indicated by Ln-N-C angles <105°, is corroborated by DFT calculations and NBO analysis.

  18. Upgradation in SCADA and PLC of existing LN{sub 2} control system for SST-1

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Pradip, E-mail: pradip@ipr.res.in; Mahesuria, Gaurang; Panchal, Rohit; Patel, Rakesh; Sonara, Dashrath; Pitroda, Dipen; Nimavat, Hiren; Tanna, Vipul; Pradhan, Subrata

    2016-11-15

    Highlights: • The control system of LN{sub 2} Management System of SST-1 is designed on PLC and SCADA. • The implementation and results of up-gradation in PLC and SCADA are reported. • The up-gradation in PLC and SCADA has improved the reliability & availability of SST-1 LN{sub 2} system. - Abstract: Helium Refrigerator/Liquefier system of Steady State Superconducting Tokamak (SST-1) incorporates Liquid Nitrogen (LN{sub 2}) pre-cooling system. LN{sub 2} is used for 80 K thermal shields of SST-1, current feeder system and integrated flow distribution and control system. The LN{sub 2} management system is distributed system and requires automatic control. Initially LN{sub 2} control system had Citect based Supervisory Control and Data Acquisition (SCADA) and Koyo make Programmable Logic Controller (PLC). With the passage of time and due to unavailability of their hardware, it is being obsoleted. So, the requirements of new PLC and SCADA systems have been envisaged to make uninterruptable operation of SST-1 cryogenic system. Therefore, Wonderware SCADA and Schneider Electric make PLC is programmed to replace Citect SCADA and Koyo PLC. New control features have been added in upgraded control system for better management of LN{sub 2} system. This upgradation of SCADA and PLC is completed, tested successfully and in operation. Operational performance highlights of the new upgraded system are presented in this paper.

  19. A series of lithium rare earth polyphosphates [LiLn(PO 3) 4] (Ln = Tb, Ho, Yb) and their structural, optical, and electronic properties

    Science.gov (United States)

    Fang, Ming; Cheng, Wen-Dan; Xie, Zhi; Zhang, Hao; Zhao, Dan; Zhang, Wei-Long; Yang, Song-Lin

    2008-11-01

    The structural, optical, and electronic properties of a series of lithium rare earth polyphosphates [LiLn(PO 3) 4] [Ln = Tb(1), Ho(2), Yb(3)] have been investigated by means of single-crystal X-ray diffraction, spectroscopic measurements and calculations of energy-band structures, density of states, and optical response functions by density functional methods. These LiLn(PO 3) 4 systems are monoclinic with space group C2 /c and Z = 4. Their unit-cell parameters decrease as the ionic radius of Ln 3+ decreases (Tb 3+ > Ho 3+ > Yb 3+). Both (PO 4) 3- zig-zag chains and infinite chains formed by the alternate connection of LnO 8 polyhedra and LiO 4 tetrahedra run parallel to the b-axis in the structure. The energy-band structures, density of states, the chemical bonds, and optical properties have been investigated by density functional methods for LiYb(PO 3) 4.

  20. Synthesis, structures, and luminescent and magnetic properties of Ln-Ag heterometal-organic frameworks.

    Science.gov (United States)

    Zhao, Xiao-Qing; Zhao, Bin; Wei, Shi; Cheng, Peng

    2009-12-07

    A series of Ln-Ag heterometal-organic frameworks based on 4-hydroxylpyridine-2,6-dicarboxylic acid (H(3)CAM) with formulas {LaAg(2)(CAM)(HCAM)(H(2)O)(2)}(n) (1), {LnAg(HCAM)(2)(H(2)O)(3)}(n) (Ln = Pr, 2; Nd, 3; Sm, 4; Eu, 5), and {LnAg(3)(CAM)(2)(H(2)O)}(n) (Ln = Gd, 6; Tb, 7; Dy, 8; Tm, 9; Yb, 10), have been synthesized with the hydrothermal reaction of Ln(OH)(3), Ag(2)O, and H(3)CAM at 160 degrees C. The single-crystal X-ray diffraction analyses reveal that three kinds of structures are exclusively governed by the size of lanthanide ions and the progression of structures is mainly ascribed to the lanthanide contraction effect. Compound 1 consists of a 3D network with an alpha-polonium-like Ag(+)-homometallic net and helical La(3+) chain. Compounds 2-5 display a 2D honeycomb-like structure with 18-membered Ln(3)Ag(3)O(12) motifs, and compounds 6-10 can be described as a sandwich-like 3D framework built of a 3D Ag(+)-homometallic net and 2D Ln(3+)-4(4) layer. In 4 (Sm), 5 (Eu), 7 (Tb), and 8 (Dy) samples, the efficient energy transfer from CAM to Ln(III) ions was observed, which results in the typical intense emissions of corresponding Ln(III) ions in the visible region, and the strongest emissions are (4)G(5/2) --> (6)H(7/2) (602 nm), (5)D(0) --> (7)F(2) (614 nm), (5)D(4) --> (7)F(5) (548 nm), and (4)F(9/2) --> (6)H(13/2) (576 nm) transitions. Variable-temperature magnetic susceptibility measurements of 6-10 show that the ferromagnetic interaction between gadolinium(III) ions appears in 6, whereas the mu(eff) values of 7-10 smoothly decrease on cooling. For the orbital contribution of Ln(III) ions, it is very difficult to determine the intrinsic magnetic interactions between Ln(III) ions.

  1. In pursuit of the rhabdophane crystal structure: from the hydrated monoclinic LnPO{sub 4}.0.667H{sub 2}O to the hexagonal LnPO{sub 4} (Ln = Nd, Sm, Gd, Eu and Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Mesbah, Adel, E-mail: adel.mesbah@cea.fr [ICSM, UMR 5257 CNRS – CEA – ENSCM – Université de Montpellier, Site de Marcoule - Bât 426, BP 17171, 30207 Bagnols/Cèze (France); Clavier, Nicolas [ICSM, UMR 5257 CNRS – CEA – ENSCM – Université de Montpellier, Site de Marcoule - Bât 426, BP 17171, 30207 Bagnols/Cèze (France); Elkaim, Erik [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex (France); Szenknect, Stéphanie; Dacheux, Nicolas [ICSM, UMR 5257 CNRS – CEA – ENSCM – Université de Montpellier, Site de Marcoule - Bât 426, BP 17171, 30207 Bagnols/Cèze (France)

    2017-05-15

    The dehydration process of the hydrated rhabdophane LnPO{sub 4}.0.667H{sub 2}O (Ln = La to Dy) was thoroughly studied over the combination of in situ high resolution synchrotron powder diffraction and TGA experiments. In the case of SmPO{sub 4}.0.667H{sub 2}O (monoclinic, C2), a first dehydration step was identified around 80 °C leading to the formation of SmPO{sub 4}.0.5H{sub 2}O (Monoclinic, C2) with Z =12 and a =17.6264(1) Å, b =6.9704(1) Å, c =12.1141(1) Å, β=133.74(1) °, V =1075.33(1) Å{sup 3}. In agreement with the TGA and dilatometry experiments, all the water molecules were evacuated above 220 °C yielding to the anhydrous form, which crystallizes in the hexagonal P3{sub 1}21 space group with a =7.0389(1) Å, c =6.3702(1) Å and V =273.34(1) Å{sup 3}. This study was extended to selected LnPO{sub 4}.0.667H{sub 2}O samples (Ln= Nd, Gd, Eu, Dy) and the obtained results confirmed the existence of two dehydration steps before the stabilization of the anhydrous form, with the transitory formation of LnPO{sub 4}.0.5H{sub 2}O. - Graphical abstract: The dehydration process of the rhabdophane SmPO{sub 4}.0.667H{sub 2}O was studied over combination of in situ high resolution synchrotron powder diffraction and TGA techniques, a first dehydration was identified around 80 °C leading to the formation of SmPO{sub 4}.0.5H{sub 2}O (Monoclinic, C2). Then above 220 °C, the anhydrous form of the rhabdophane SmPO{sub 4} was stabilized and crystallizes in the hexagonal P3{sub 1}21 space group. - Highlights: • In situ synchrotron powder diffraction was carried out during the dehydration of the rhabdopahe LnPO{sub 4}.0.667H{sub 2}O. • The heat of the rhabdophane LnPO{sub 4}.0.667H{sub 2}O leads to LnPO{sub 4}.0.5H{sub 2}O then to anhydrous rhabdophane LnPO{sub 4}. • LnPO{sub 4}.0.5H{sub 2}O (monoclinic, C2) and LnPO{sub 4} (Hexagonal, P3{sub 1}21) were solved over the use of direct methods.

  2. Local Reversion of Cold Formed AISI 301LN

    Science.gov (United States)

    Järvenpää, A.; Jaskari, M.; Hietala, M.; Mäntyjärvi, K.

    This study demonstrates applying laser heat treatment for reversion treatments of cold-formed AISI 301LN. Sheets were cold- rolled to final thicknesses of 1.5 and 3 mm (65pct reduction), having martensite fraction of 70-95%. Sheets were heated locally by a laser beam to various peak temperatures to obtain different degrees of martensite reversion to austenite. Mechanical properties and formability of grain-refined and coarse-grained structures were measured by tensile, bending and Erichsen cup tests. In addition to standard Erichsen cup test, additional interrupted tests were carried out, where cups were first stretched close to the critical strain. Drawn cups were then heated locally by a laser beam to revitalize the structure and thereby enhance the formability in the following cupping test until failure. Various structures were produced: completely reverted microstructures (T > 700 °C) with grain sizes 0.9 - 2 μm in addition to partially reverted structure (T treatment is suitable for the reversion treatment to refine the austenite grain size. Refinement of the austenitic structures increased strength properties and the formability was better than with coarse grained structures having the same strength. Especially the yield strength was significantly enhanced, being around 900 MPa in the strongest reverted structure compared to the 300-400 MPa of the coarse grained austenitic structure. It was demonstrated that the local laser treatment restored formability of the drawn cups, allowing stretching to be continued.

  3. Cyclometallated ruthenium (II) carbonyl complexes with 1 ...

    Indian Academy of Sciences (India)

    A facile method for the synthesis of a series of cyclometallated ruthenium(II) carbonyl complexes with 1-pyrenaldehyde 4-R-3-thiosemicarbazones (H2Ln where the two H's represent the dissociable thioamide and pyrenyl protons; R = H, Me and Ph) has been described. The characterization of the complexes having the ...

  4. Synthesis, crystal structure and photophysical properties of europium(III) and terbium(III) complexes with pyridine-2,6-dicarboxamide

    NARCIS (Netherlands)

    Tanase, S.; Gallego, P.M.; Gelder, R. de; Fu, W.T.

    2007-01-01

    The reactions of pyridine-2,6-dicarboxamide with europium(III) and terbium(III) triflates led to the formation of mononuclear complexes of formula [Ln(pcam)(3)](CF3SO3)(3) (Ln = Eu 1, Tb 2; pcam stands for pyridine-2,6-dicarboxamide). From single-crystal X-ray diffraction analysis, the complexes

  5. Highly emissive Zn-Ln metal-organic frameworks with an unusual 3D inorganic subnetwork.

    Science.gov (United States)

    Liu, C B; Ferreira, R A S; Almeida Paz, F A; Cadiau, A; Carlos, L D; Fu, L S; Rocha, J; Shi, F-N

    2012-08-18

    Mixed zinc-lanthanide (Zn-Ln) metal-organic frameworks (MOFs) based on the 3,5-pyrazoledicarboxylate ligand exhibit an unusual three-dimensional (3D) inorganic subnetwork and display highly efficient photoluminescence.

  6. Síntesis hidrotermal de monocristales LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er

    Directory of Open Access Journals (Sweden)

    Señarís Rodríguez, M. A.

    2008-08-01

    Full Text Available Ten single crystals of the series LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er were synthesized by hydrothermal synthesis in a single step and without subsequent thermal treatments from aqueous solutions of metals salts at 240 ºC. The obtained single crystals have a size of various micrometers and their morphology changes throughout the serie: they are polygonal in the case of the compounds with Ln= Pr, Nd, Sm, Eu and Gd and needle-like in the case of the compounds with Ln= Y, Tb, Dy, Ho and Er. After the analysis of the obtained products employing different conditions of synthesis we attributed the different morphology to a greater growth rate along the c axis when the smaller ions (Y, Tb, Dy, Ho y Er are involved, due to their better adaptation to the compound’s crystal structure.Se han conseguido preparar monocristales de 10 óxidos mixtos de la serie LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er mediante síntesis hidrotermal optimizada, en un único paso y sin tratamientos térmicos posteriores partiendo de las correspondientes sales metálicas en disolución acuosa a 240 ºC. Los monocristales obtenidos son relativamente grandes, de varias micras y su morfología varía a lo largo de la serie: es poligonal en el caso de los compuestos de los lantánidos del inicio de la serie (Ln= Pr, Nd, Sm, Eu y Gd y acicular en el caso de los compuestos de Y y de los lantánidos del final de la serie (Ln= Tb, Dy, Ho y Er. Tras el análisis de los productos obtenidos empleando distintas condiciones de síntesis atribuimos la diferente morfología a una mayor velocidad de crecimiento cristalino a lo largo del eje c cuando intervienen los iones más pequeños (Y, Tb, Dy, Ho y Er debido a la mejor adaptación de éstos últimos a la estructura cristalina del compuesto.

  7. CATALYTIC OLIGOMERIZATION OF TERMINAL ALKYNES BY LANTHANIDE CARBYLS (ETA-5-C5ME5)2LNCH(SIME3)2 (LN=Y,LA,CE)

    NARCIS (Netherlands)

    HEERES, HJ; TEUBEN, JH

    Lanthanide and group 3 carbyls Cp*2LnCH(SiMe3)2 (1, Ln = Y; 2, Ln = La; 3, Ln = Ce) are active catalyst precursors for the oligomerization of terminal alyknes HC = CR (R = alkyl, aryl, SiMe3). The regioselectivity and the extent of oligomerization depend strongly on the lanthanide applied as well as

  8. Crystal structure and luminescence of complexes of Eu(III) and Tb(III) with furan-2,5-dicarboxylate

    NARCIS (Netherlands)

    Akerboom, S.; Fu, W.T.; Lutz, M.|info:eu-repo/dai/nl/304828971; Bouwman, E.

    2012-01-01

    Four new Ln(III) complexes (Ln = Eu, Tb) with furan-2,5-dicarboxylic acid (H2FDA) as a ligand have been synthesized and characterized in the solid state. Luminescence studies indicate that the compounds exhibit line-like luminescence characteristic of the lanthanide centre upon excitation in the

  9. Optimizing millisecond time scale near-infrared emission in polynuclear chrome(III)-lanthanide(III) complexes.

    Science.gov (United States)

    Aboshyan-Sorgho, Lilit; Nozary, Homayoun; Aebischer, Annina; Bünzli, Jean-Claude G; Morgantini, Pierre-Yves; Kittilstved, Kevin R; Hauser, Andreas; Eliseeva, Svetlana V; Petoud, Stéphane; Piguet, Claude

    2012-08-01

    This work illustrates a simple approach for optimizing long-lived near-infrared lanthanide-centered luminescence using trivalent chromium chromophores as sensitizers. Reactions of the segmental ligand L2 with stoichiometric amounts of M(CF(3)SO(3))(2) (M = Cr, Zn) and Ln(CF(3)SO(3))(3) (Ln = Nd, Er, Yb) under aerobic conditions quantitatively yield the D(3)-symmetrical trinuclear [MLnM(L2)(3)](CF(3)SO(3))(n) complexes (M = Zn, n = 7; M = Cr, n = 9), in which the central lanthanide activator is sandwiched between the two transition metal cations. Visible or NIR irradiation of the peripheral Cr(III) chromophores in [CrLnCr(L2)(3)](9+) induces rate-limiting intramolecular intermetallic Cr→Ln energy transfer processes (Ln = Nd, Er, Yb), which eventually produces lanthanide-centered near-infrared (NIR) or IR emission with apparent lifetimes within the millisecond range. As compared to the parent dinuclear complexes [CrLn(L1)(3)](6+), the connection of a second strong-field [CrN(6)] sensitizer in [CrLnCr(L2)(3)](9+) significantly enhances the emission intensity without perturbing the kinetic regime. This work opens novel exciting photophysical perspectives via the buildup of non-negligible population densities for the long-lived doubly excited state [Cr*LnCr*(L2)(3)](9+) under reasonable pumping powers.

  10. Hydrothermal synthesis and luminescence of lanthanide complexes sensitized with dpphen

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hongzhen [Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211 (China); Lu, Guanzhong, E-mail: gzhlu@ecust.edu.cn [Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237 (China)

    2014-01-15

    Three new lanthanide complexes [Ln(dpphen)(L)(NO{sub 3})] (Ln=Tb(1), Eu(2), Nd(3), H{sub 2}L=glutaric acid, dpphen=4,7-diphenyl-1,10-phenanthroline) have been synthesized hydrothermally by the reaction of H{sub 2}L, dpphen and Ln(III) ions. The X-ray diffraction analysis reveals that three coordination polymers have similar structures. The Ln(III) ions are nine coordinated and glutarate ligands bridge Ln(III) to form 1D polymer chains. The solid-state luminescence of complexes 1 and 2 was investigated at room temperature. The complexes 1 and 2 exhibited strong green and red luminescence under ultraviolet light. The {sup 5}D{sub 4}→{sup 7}F{sub j} (j=6, 5, 4 and 3) transition emissions of Tb(III) and the {sup 5}D{sub 0}→{sup 7}F{sub j} (j=0–4) transition emissions of Eu(III) were observed in their emission spectra. The strong luminescence of complexes 1 and 2 demonstrates that luminescence of lanthanide coordination polymers is sensitized by an effective energy-transfer from dpphen ligand to Ln(III) ions. Moreover, the magnetic properties of complexes 1–3 were also investigated. -- Graphical abstract: Three new coordination polymers, [Ln(dpphen)(L)(NO{sub 3})] (Ln=Tb(1), Eu(2), Nd(3), H{sub 2}L=glutaric acid) were synthesized hydrothermally. Ln(III) ions are nine coordinated and the glutarate ligands bridge the Ln(III) to from 1D polymer chains. The complexes Tb(III) and Eu(III) exhibit strong green and red luminescence respectively. Highlights: • Tb{sup 3+}- and Eu{sup 3+}-dpphen complexes exhibit strong green and red light respectively. • Luminescence of ligand is suppressed in complexes due to efficient ligand-to-metal energy transfer. • Three 1D chain-like new coordination polymers were synthesized hydrothermally. • Three lanthanide coordination polymers exhibit good thermal stability.

  11. Interplay of structural chemistry and magnetism in perovskites; A study of CaLn2Ni2WO9; Ln=La, Pr, Nd

    Science.gov (United States)

    Chin, Chun-Mann; Paria Sena, Robert; Hunter, Emily C.; Hadermann, Joke; Battle, Peter D.

    2017-07-01

    Polycrystalline samples of CaLn2Ni2WO9 (Ln=La, Pr, Nd) have been synthesized and characterised by a combination of X-ray and neutron diffraction, electron microscopy and magnetometry. Each composition adopts a perovskite-like structure with a 5.50, b 5.56, c 7.78 Å, β 90.1° in space group P21/n. Of the two crystallographically distinct six-coordinate sites, one is occupied entirely (Ln=Pr) or predominantly (Ln=La, Nd) by Ni2+ and the other by Ni2+ and W6+ in a ratio of approximately 1:2. None of the compounds shows long-range magnetic order at 5 K. The magnetometry data show that the magnetic moments of the Ni2+ cations form a spin glass below 30 K in each case. The Pr3+ moments in CaPr2Ni2WO9 also freeze but the Nd3+ moments in CaNd2Ni2WO9 do not. This behaviour is contrasted with that observed in other (A,A')B2B'O9 perovskites.

  12. 3d/4f Metal Complexes of Phenolic Oximes New Binding Sites on Anderson Polyoxometalates Metal Complexes of the New THAME Ligand

    DEFF Research Database (Denmark)

    Sethi, Waqas

    III =DyIII, ErIII, TbIII and YIII). The complexes are synthesised by mixing the appropriate metal salts andligands in basic MeOH or in a mixture of MeOH and MeCN. The metallic skeleton of [LnIII2MnIII4]and [LnIII2MnIII2MnIV2] can be viewed as made of two edge sharing [Ln2Mn2] tetrahedra or...... to be coordinatedto SMMs as well as onto other transition metal complexes, via different synthetic strategies. These synthetic routes did not result in the crystallisation of any new compounds. A new hexadentate ligand tris(((2-hydroxyethyl)-amino)methyl)ethane (THAME) was synthesised and characterised. THAME......Derivatives of phenolic oximes have been used to synthesise two large families of coordinationcomplexes namely [LnIII2MnIII4] and [LnIII2MnIII2MnIV2]. The [LnIII2MnIII4] family can be subdivided into two structural types. Complexes 1 to 9 (Type 1) can be represented by the general formula [LnIII2Mn...

  13. Fabrication of Ln-MOFs with color-tunable photoluminescence and sensing for small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shengyan; Shan, Liang; Fan, Yong; Jia, Jia; Xu, Jianing, E-mail: xujn@jlu.edu.cn; Wang, Li, E-mail: lwang99@jlu.edu.cn

    2017-01-15

    Three isomorphic lanthanide metal-organic frameworks (Ln-MOFs) [LnL(H{sub 2}O){sub 2}]·2H{sub 2}O (Ln=Tb for 1, Eu for 2, Gd for 3) have been constructed from flexible organic ligand 4-(2-carboxyphenoxy)benzene-1,3-dioic acid (H{sub 3}L). They exhibit two-dimensional (2D) layered structure with the rhombus windows along the b axis. This network can be described as a shubnikov plane net with Schäfli symbol of (4{sup 3}){sub 2}(4{sup 6}.6{sup 6}.8{sup 3}). Solid state luminescent studies indicate that 1 and 2 show the characteristic red, and green emissions of the corresponding Ln{sup 3+} ions, respectively, while 3 exhibits blue emission arising from the organic ligand. Then by adjusting the relative amounts of different luminescent components into the well-defined host framework, a series of new co-doped Ln-MOF, Tb{sub 1−x}Eu{sub x}L (4) (x refers to the molar ratios of Eu{sup 3+} and Tb{sup 3+}), with tunable luminescence have been fabricated. The luminescent color of 4 can be tuned from green to red due to the energy transfer from the Tb{sup 3+} to Eu{sup 3+} ions by changing the doping concentration of the Eu{sup 3+} ions. In addition, 2 exhibits good stability in different solvents and excellent fluorescence sensing for small molecules, especially for CH{sub 3}CN and nitrobenzene. - Graphical abstract: A series of isomorphic 2D layered Ln-MOFs have been constructed from flexible tricarboxylic ligand, showing tunable luminescence and excellent fluorescence sensing for small molecules, respectively. - Highlights: • Three isomorphic 2D layered Ln-MOFs were constructed by flexible tricarboxylic acid. • A series of Eu{sup 3+}/Tb{sup 3+} doped Ln-MOF 4 were fabricated and showed tunable luminescence. • Ln-MOF 2 exhibited excellent fluorescence sensing for small molecules.

  14. The first dinitrile frameworks of the rare earth elements: infinity(3)[LnCl3(1,4-Ph(CN)2)] and infinity(3)[Ln2Cl6(1,4-Ph(CN)2)], Ln = Sm, Gd, Tb, Y; access to novel metal-organic frameworks by solvent free synthesis in molten 1,4-benzodinitrile.

    Science.gov (United States)

    Höller, Christoph J; Müller-Buschbaum, Klaus

    2008-11-03

    The three-dimensional frameworks infinity(3)[LnCl3(1,4-Ph(CN)2)] of the lanthanides Ln = Sm (1), Gd (2), Tb (3), and infinity(3)[Ln2Cl6(1,4-Ph(CN)2)] for the group 3 metal Y (4) were obtained as single crystalline materials by the reaction of the anhydrous chlorides of the referring rare earth elements with a melt of 1,4-benzodinitrile. No additional solvents were used for the reactions. The dinitrile ligand is strongly coordinating and substitutes parts of the chlorine coordination. The Ln halide structures are reduced to two-dimensional networks, whereas coordination of both nitrile functions to the metal ions renders bridging in the third direction accessible. This enables formation of new metal organic framework (MOF) structure types with the large 1,4-benzodinitrile spacers interlinking infinity (2)[LnCl3] planes. In comparison to 1,4-Ph(CN)2 the mono functional benzonitrile ligand does not constitute framework structures, which is underlined by comparison with a reaction of yttrium chloride with PhCN resulting in the molecular complex [Y2Cl6(PhCN)6] (5) with end-on coordination PhCN ligands. The coordination spheres of the rare earth ions consist of double capped (infinity(3)[LnCl3(1,4-Ph(CN)2)] (1-3)) as well as single capped trigonal prisms (infinity(3)[Ln2Cl6(1,4-Ph(CN)2)] (4)) of chloride ions and N[triple bond]C groups while 5 displays edge sharing pentagonal bipyramids as coordination polyhedra. Sm (1), Gd (2), and Tb (3) exhibit isotypic framework structures with intercrossing dinitrile ligands. The group 3 metal Y (4) gives a framework with a coplanar arrangement of ligands and a lower ligand content. The largest cavities within the MOF structures of 1-4 have diameters of 3.9-8.0 A. All compounds were identified by single crystal X-ray analysis. Mid IR, Far IR, and Raman spectroscopy, microanalyses and simultaneous Differential Thermal Analysis-Thermogravimetry (DTA/TG) were also carried out to characterize the products. Crystal data for infinity(3

  15. Influence of the crystal structure on the stability of Ln{sup 2+} in strontium borates

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, V.P. [Physico-Chemical Institute, Ukrainian Academy of Sciences, 86 Lustdorfskaya str., 65080 Odesa (Ukraine)], E-mail: ssclab@ukr.net; Berezovskaya, I.V.; Efryushina, N.P. [Physico-Chemical Institute, Ukrainian Academy of Sciences, 86 Lustdorfskaya str., 65080 Odesa (Ukraine); Voloshinovskii, A.S.; Stryganyuk, G.B. [Ivan Franko National University of Lviv, 8 Kyryla i Mefodiya str., 29005 Lviv (Ukraine)

    2007-04-15

    The results of luminescence measurements on Ln (Eu, Yb) doped alkaline earth (M=Ca,Sr) borates M{sub 3}(BO{sub 3}){sub 2}, MB{sub 2}O{sub 4}, M{sub 2}B{sub 5}O{sub 9}X(X=Cl,Br), MB{sub 6}O{sub 10}, MB{sub 4}O{sub 7} after high-temperature annealing in various atmospheres are reported and discussed. The stability of Ln{sup 2+}(Ln=Eu,Yb) is found to increase in the sequence Sr{sub 3}(BO{sub 3}){sub 2}Ln{sup 3+}. A simple criterion is proposed to predict the stability of Ln{sup 2+} in alkaline earth borates.

  16. Consideration of sub-cooled LN2 circulation system for HTS power machines

    Science.gov (United States)

    Yoshida, Shigeru; Hirai, Hirokazu; Nara, N.; Nagasaka, T.; Hirokawa, M.; Okamoto, H.; Hayashi, H.; Shiohara, Y.

    2012-06-01

    We consider a sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The planned circulation system consists of a sub-cool heat exchanger (subcooler) and a circulation pump. The sub-cooler will be connected to a neon turbo- Brayton cycle refrigerator with a cooling power of 2 kW at 65 K. Sub-cooled LN will be delivered into the sub-cooler by the pump and cooled within it. Sub-cooled LN is adequate fluid for cooling HTS power equipment, because its dielectric strength is high and it supports a large critical current. However, a possibility of LN solidification in the sub-cooler is a considerable issue. The refrigerator will produce cold neon gas of about 60 K, which is lower than the nitrogen freezing temperature of 63 K. Therefore, we designed two-stage heat exchangers which are based on a plate-fin type and a tube-intube type. Process simulations of those heat exchangers indicate that sub-cooled LN is not frozen in either sub-cooler. The plate-fin type sub-cooler is consequently adopted for its reliability and compactness. Furthermore, we found that a cooling system with a Brayton refrigerator has the same total cooling efficiency as a cooling system with a Stirling refrigerator.

  17. Fabrication of Ln-MOFs with color-tunable photoluminescence and sensing for small molecules

    Science.gov (United States)

    Wang, Shengyan; Shan, Liang; Fan, Yong; Jia, Jia; Xu, Jianing; Wang, Li

    2017-01-01

    Three isomorphic lanthanide metal-organic frameworks (Ln-MOFs) [LnL(H2O)2]·2H2O (Ln=Tb for 1, Eu for 2, Gd for 3) have been constructed from flexible organic ligand 4-(2-carboxyphenoxy)benzene-1,3-dioic acid (H3L). They exhibit two-dimensional (2D) layered structure with the rhombus windows along the b axis. This network can be described as a shubnikov plane net with Schäfli symbol of (43)2(46.66.83). Solid state luminescent studies indicate that 1 and 2 show the characteristic red, and green emissions of the corresponding Ln3+ ions, respectively, while 3 exhibits blue emission arising from the organic ligand. Then by adjusting the relative amounts of different luminescent components into the well-defined host framework, a series of new co-doped Ln-MOF, Tb1-xEuxL (4) (x refers to the molar ratios of Eu3+ and Tb3+), with tunable luminescence have been fabricated. The luminescent color of 4 can be tuned from green to red due to the energy transfer from the Tb3+ to Eu3+ ions by changing the doping concentration of the Eu3+ ions. In addition, 2 exhibits good stability in different solvents and excellent fluorescence sensing for small molecules, especially for CH3CN and nitrobenzene.

  18. Detection of the Unstable Hb Köln (HBB: c.295G>A) by a Capillary Electrophoresis Method.

    Science.gov (United States)

    Li, You-Qiong; Ye, Li-Hua; Mo, Yun

    2016-11-01

    Hb Köln (HBB: c.295G>A) is an unstable β-globin gene variant with a GTG>ATG substitution at codon 98. This variant is quite frequent in Europe and the USA but rare in China. It can easily be misdiagnosed as Hb Constant Spring (Hb CS; HBA2: c.427T>C) by high performance liquid chromatography (HPLC), but detection and quantification of both Hb Köln and degraded Hb Köln by capillary electrophoresis (CE) are possible. Thus, we concluded that CE was the preferred method for Hb Köln detection.

  19. Ordered oxygen deficient '112' perovskites, LnBaCo2 : complex ...

    Indian Academy of Sciences (India)

    Administrator

    2005; Seikh et al 2008a) from one sample to the other. Clearly, for δ = 0, cobalt is purely trivalent, with half ... content of these samples is absolutely necessary in order to interpret the magnetic and transport properties of ..... devoted to the study of this property (Maignan et al 1997;. Respaud et al 2001; Khalyavin et al 2003; ...

  20. Cathodoluminescence response of natural and synthetic lanthanide-rich phosphates (Ln3+: Ce, Nd)

    Science.gov (United States)

    Barrera-Villatoro, A.; Boronat, C.; Rivera-Montalvo, T.; Correcher, V.; Garcia-Guinea, J.; Zarate-Medina, J.

    2017-12-01

    This paper reports on the cathodoluminescence (CL) emission of both natural and synthetic lanthanide-rich phosphates (Ln3+: Ce, Nd) previously characterized by X-ray Diffraction (XRD), Environmental Scanning Electronic Microscopy (ESEM) and Energy Dispersive Spectroscopy. The thermal treatment at 700 °C performed on the synthetic sample obtained by chemical precipitation, promotes increasing of the crystallinity degree giving rise to a phase transition from the hexagonal (comprising monazite and rabdophane) into the monoclinic (cerianite and monazite) structures detected by XRD. Despite the size and the morphology of the grains are similar under ESEM, it could be appreciated significant differences among CL signals attending to the shape (with well-defined peaks for the annealed sample) and intensity (with lower emission for the non-thermally pretreated synthetic phosphate). The main wavebands centered at (i) 360, 380 and 490 nm are associated respectively with 5D3/2 → 2F5/2 and 5D3/2 → 2F7/2 transitions as well as a redox reaction assigned to the presence of Ce3+, (ii) 276, 424, 516 and 531 nm are linked respectively to 2G9/2→4I9/2, 2P1/2→4I9/2, 4G9/2→4I9/2 and 4G7/2→4I9/2 Nd3+ transitions and (iii) 400-490 nm is due to non-bridging oxygen hole centers related to the tetrahedral PO43- groups or structural defects for the heated synthetic samples. The natural sample from Madagascar, with a very complex CL spectrum, displays a characteristic band emission in the green-yellow and red regions corresponding to [UO2]2+ groups and Sm3+ respectively.

  1. Synthesis and characterization of LnAg(WO{sub 4})(MoO{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Martinez, F. [Universidad Politecnica de Madrid, E.U.I.T. Industrial, Ronda de Valencia 3, 28012 Madrid (Spain)], E-mail: francisco.fernandezm@upm.es; Colon, C.; Montero, J.L.; Atanes, E. [Universidad Politecnica de Madrid, E.U.I.T. Industrial, Ronda de Valencia 3, 28012 Madrid (Spain); Rivero, C. [Universidad Politecnica de Madrid, E.T.S.I. Telecomunicaciones, Avda. Complutense s/n, Ciudad Universitaria, 28040 Madrid (Spain)

    2008-02-28

    Polycrystalline LnAg(WO{sub 4})(MoO{sub 4}) powders, with Ln = La to Lu and Y, have been obtained by ceramic method. Rietveld refinement for all compounds reveals that they present tetragonal symmetry, space group I4{sub 1}/a (No. 88), where the Ln{sup 3+}/Ag{sup +} ions are located in the 4a atomic positions, since the W/Mo are randomly distributed into 4b crystal sites. In these compounds, a and b lattice parameters take values between those corresponding to tungstate and molybdate compounds. A progressive decrease in the lattice parameters is observed in going from La to Lu derivatives as a consequence of the well-known lanthanide contraction.

  2. The magnetic properties of the Ln sub 2 BaCuO sub 5

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Sanchez, A.; Saez-Puche, R.; Alario-Franco, M.A. (Universidad Complutense de Madrid (ES). Facultad de Ciencias Quimicas)

    1991-01-01

    The temperature dependence of the magnetic susceptibility for the different Ln{sub 2}BaCuO{sub 5} oxides (green phases) where Ln is Gd, Dy and Ho which after appears as impurities in the synthesis of high temperature superconductors, reveals the existence of antiferromagnetic ordering for both Cu and Ln sublattices. In the case of the isostructural Lu{sub 2}BaCuO{sub 5} the Cu{sup 2+} ions are ordered at about the same temperature found for Y{sub 2}BaCuO{sub 5}. The specific magnetic behavior of Nd{sub 2}BaCuO{sub 5} can be explained by considering its different structure-type.

  3. LnBSb2O8 (Ln = Sm, Eu, Gd, Tb): A Series of Lanthanide Boroantimonates with Unusual 3D Anionic Structures.

    Science.gov (United States)

    Yan, Dong; Mao, Fei-Fei; Mao, Jiang-Gao

    2016-10-17

    A series of lanthanide boroantimonates, namely, LnBSb2O8 (Ln = Sm 1, Eu 2, Gd 3, and Tb 4) have been successfully synthesized by high temperature solid-state reactions for the first time. They are isostructural and feature novel three-dimensional (3D) frameworks composed of 2D [Sb3O12]9- layers interconnected by 1D [SbBO7]6- chains with remaining BO3 groups hanging on the walls of the 1D 6-membered-ring (MR) tunnels along the a-axis, and the lanthanide ions filled in the voids of the anionic structure. They exhibit high thermal stability (up to 900 °C). Luminescent studies suggest that compounds 1, 2, and 4 have potential application as orange, red, and green light luminescent materials, respectively. Magnetic measurements reveal ferromagnetic coupling interactions in compound 3 and antiferromagnetic coupling interactions between magnetic centers in compounds 1, 2, and 4.

  4. Strong stokes and upconversion luminescence from ultrasmall Ln(3+)-doped BiF3 (Ln=Eu3+, Yb3+/Er3+) nanoparticles confined in a polymer matrix.

    Science.gov (United States)

    Sarkar, Shyam; Dash, Armita; Mahalingam, Venkataramanan

    2014-02-01

    Heavy metal fluorides like BiF3 as a host for lanthanide ions are of interest as bismuth is the only heavy metal that is nontoxic. In this work, we report the synthesis of highly water-dispersible ultrasmall BiF3 nanoparticles about 6 nm in size within a poly(vinyl pyrrolidone) matrix by a hydrothermal method. Microscopy analysis reveals that the nanoparticles are well separated and confined within the polymer network. These nanoparticles were found to be excellent hosts for lanthanide (Ln(3+)) ions. Through suitable Ln(3+) doping, BiF3 exhibits strong emissions in the visible region upon both UV and near infrared (NIR) excitations. The non-toxicity of both bismuth and PVP can be advantageous for the potential use of BiF3 nanoparticles in drug delivery and bioimaging. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Nanostructured LnBaCo2O6− (Ln = Sm, Gd with layered structure for intermediate temperature solid oxide fuel cell cathodes

    Directory of Open Access Journals (Sweden)

    Augusto E. Mejía Gómez

    2017-04-01

    Full Text Available In this work, we present the combination of two characteristics that are beneficial for solid oxide fuel cell (SOFC cathodic performance in one material. We developed and evaluated for the first time nanostructured layered perovskites of formulae LnBaCo2O6-d with Ln = Sm and Gd (SBCO and GBCO, respectively as SOFC cathodes, finding promising electrochemical properties in the intermediate temperature range. We obtained those nanostructures by using porous templates to confine the chemical reagents in regions of 200-800 nm. The performance of nanostructured SBCO and GBCO cathodes was analyzed by electrochemical impedance spectroscopy technique under different operating conditions using Gd2O3-doped CeO2 as electrolyte. We found that SBCO cathodes displayed lower area-specific resistance than GBCO ones, because bulk diffusion of oxide ions is enhanced in the former. We also found that cathodes synthesized using smaller template pores exhibited better performance.

  6. Synthesis, spectroscopic characterization and antibacterial studies of lanthanide(III) Schiff base complexes containing N, O donor atoms

    Science.gov (United States)

    Lekha, L.; Raja, K. Kanmani; Rajagopal, G.; Easwaramoorthy, D.

    2014-01-01

    A series of six Ln(III) Schiff base complexes, Pr(III), Sm(III), Gd(III), Tb(III), Er(III) and Yb(III), were synthesized using sodium salt of Schiff base, 2-[(5-bromo-2-hydroxy-benzylidene)-amino]-3-hydroxy-propionic acid, derived from L-serine and 5-bromosalicylaldehyde. These complexes having general formula [Ln(L)(NO3)2(H2O)]·NO3 were characterized by elemental analysis, conductivity measurements, UV-Vis, FT-IR, mass spectrometry and fluorescence studies. Elemental analysis and conductivity measurements suggest the complexes have a 1:1 stoichiometry. From the spectral studies it has been concluded that Ln(III) complexes display eight coordination. The Schiff base and its Ln(III) metal complexes have also been screened for their antibacterial activities by Agar diffusion method.

  7. Validation of the CQU-DTU-LN1 series of airfoils

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Zhu, Wei Jun; Fischer, Andreas

    2014-01-01

    The CQU-DTU-LN1 series of airfoils were designed with an objective of high lift and low noise emission. In the design process, the aerodynamic performance is obtained using XFOIL while noise emission is obtained with the BPM model. In this paper we present some validations of the designed CQU......, the designed Cl and Cl/Cd agrees well with the experiment and are in general higher than those of the NACA airfoil. For the acoustic features, the noise emission of the LN118 airfoil is compared with the acoustic measurements and that of the NACA airfoil. Comparisons show that the BPM model can predict...

  8. Strain-rate dependent fatigue behavior of 316LN stainless steel in high-temperature water

    Science.gov (United States)

    Tan, Jibo; Wu, Xinqiang; Han, En-Hou; Ke, Wei; Wang, Xiang; Sun, Haitao

    2017-06-01

    Low cycle fatigue behavior of forged 316LN stainless steel was investigated in high-temperature water. It was found that the fatigue life of 316LN stainless steel decreased with decreasing strain rate from 0.4 to 0.004 %s-1 in 300 °C water. The stress amplitude increased with decreasing strain rate during fatigue tests, which was a typical characteristic of dynamic strain aging. The fatigue cracks mainly initiated at pits and slip bands. The interactive effect between dynamic strain aging and electrochemical factors on fatigue crack initiation is discussed.

  9. Thermochemistry of rare earth doped uranium oxides Ln x U 1-x O 2-0.5x+y (Ln = La, Y, Nd)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; Navrotsky, Alexandra

    2015-10-01

    Lanthanum, yttrium, and neodymium doped uranium dioxide samples in the fluorite structure have been synthesized, characterized in terms of metal ratio and oxygen content, and their enthalpies of formation measured by high temperature oxide melt solution calorimetry. For oxides doped with 10–50 mol % rare earth (Ln) cations, the formation enthalpies from constituent oxides (LnO1.5, UO2 and UO3 in a reaction not involving oxidation or reduction) become increasingly exothermic with increasing rare earth content, while showing no significant dependence on the varying uranium oxidation state. The oxidation enthalpy of LnxU1-xO2-0.5x+y is similar to that of UO2 to UO3 for all three rare earth doped systems. Though this may suggest that the oxidized uranium in these systems is energetically similar to that in the hexavalent state, thermochemical data alone can not constrain whether the uranium is present as U5+, U6+, or a mixture of oxidation states. The formation enthalpies from elements calculated from the calorimetric data are generally consistent with those from free energy measurements.

  10. Self-assembled Ln(III)4 (Ln = Eu, Gd, Dy, Ho, Yb) [2 × 2] square grids: a new class of lanthanide cluster.

    Science.gov (United States)

    Randell, Nicholas M; Anwar, Muhammad U; Drover, Marcus W; Dawe, Louise N; Thompson, Laurence K

    2013-06-03

    Self-assembly of the Ln(III) ions (Ln = Eu, Gd, Dy, Ho, Yb) into square [2 × 2] grid-like arrays has been readily effected using simple, symmetric ditopic ligands based on a carbohydrazone core. The metal ions are connected via single atom bridges (e.g., μ2-O(hydrazone), μ2-OH, μ2-OMe, μ2-1,1-N3(-), μ4-O), depending on reaction conditions. The Gd(III)4 examples exhibit intramolecular antiferromagnetic exchange (-J < 0.11 cm(-1)), and in one Dy(III)4 example, with a combination of μ2-1,1-N3(-), and μ4-O bridges linking adjacent metal ions, SMM behavior is observed. One thermally driven relaxation process is observed in the temperature range 10-25 K (τ0 = 6.5(1) × 10(-7) s, U(eff) = 110(1) K) in the presence of an 1800 Oe external field, employed to suppress a second quantum based relaxation process. The extended group of Ln(III) ions which submit to this controlled self-assembly, typical of the transition metal ions, indicates the general applicability of this approach to the lanthanides. This occurs despite the anticipated limitations based on larger ionic radii and coordination numbers, and is an encouraging sign for extension to larger grids with appropriately chosen polytopic ligands.

  11. High oxygen ion conduction in sintered oxides of the Bi2O3---Ln2O3 system

    NARCIS (Netherlands)

    Verkerk, M.J.; Burggraaf, A.J.

    1981-01-01

    The conditions leading to optimum conductivity of the Bi2O3---Ln2O3 system were investigated. The highest conductivity was found for Ln = Er or Tm. Ordering in the oxygen lattice was investigated using neutron diffraction. Correlations were found between the neutron diffraction data and the

  12. Prism inside. Spectroscopic and magnetic properties of the lanthanide(III) chloride oxidotungstates(VI) Ln{sub 3}Cl{sub 3}[WO{sub 6}] (Ln = La - Nd, Sm - Tb)

    Energy Technology Data Exchange (ETDEWEB)

    Dorn, Katharina V.; Blaschkowski, Bjoern; Hartenbach, Ingo [Institute for Inorganic Chemistry, University of Stuttgart (Germany); Foerg, Katharina; Netzsch, Philip; Hoeppe, Henning A. [Institute for Physics, University of Augsburg (Germany)

    2017-11-17

    The lanthanide(III) chloride oxidotungstates(VI) with the formula Ln{sub 3}Cl{sub 3}[WO{sub 6}] for Ln = La - Nd, Sm - Tb were synthesized by solid-state reactions utilizing the respective lanthanide trichloride, lanthanide sesquioxide (where available), and tungsten trioxide together with lithium chloride as flux. The title compounds crystallize hexagonally in space group P6{sub 3}/m (no. 176, a = 941-909, c = 543-525 pm, Z = 2). The structures comprise crystallographically unique Ln{sup 3+} cations surrounded by six O{sup 2-} and four Cl{sup -} anions (C.N. = 10) forming distorted tetracapped trigonal prisms as well as rather uncommon trigonal prismatic [WO{sub 6}]{sup 6-} units, whose edges are coordinated by nine Ln{sup 3+} cations. Thus, a {sup 3}{sub ∞}{([WO_6]Ln"e_9_/_3)"3"+} framework (e = edge-sharing) is created, which contains tube-shaped channels along [001] lined with chloride anions. To elucidate the spectroscopic and magnetic properties of the obtained pure phase samples, single-crystal Raman (for Ln = La - Nd, Sm-Tb), diffuse reflectance (for Ln = La, Pr, Nd, Gd), and luminescence spectroscopy (for bulk Ln{sub 3}Cl{sub 3}[WO{sub 6}] (Ln = La, Eu, Gd, Tb) and Eu{sup 3+}- or Tb{sup 3+}-doped derivatives of La{sub 3}Cl{sub 3}[WO{sub 6}] and Gd{sub 3}Cl{sub 3}[WO{sub 6}], respectively) were performed and their temperature-dependent magnetic moments (for Ln = Pr, Nd, Gd) were determined. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Complexation of biological ligands with lanthanides(III) for MRI: Structure, thermodynamic and methods; Complexation des cations lanthanides trivalents par des ligands d'origine biologique pour l'IRM: Structure, thermodynamique et methodes

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, C

    2006-07-15

    New cyclic ligands derived from sugars and amino-acids form a scaffold carrying a coordination sphere of oxygen atoms suitable to complex Ln(III) ions. In spite of their rather low molecular weights, the complexes display surprisingly high relaxivity values, especially at high field. The ACX and BCX ligands, which are acidic derivatives of modified and cyclo-dextrins, form mono and bimetallic complexes with Ln(III). The LnACX and LnBCX complexes show affinities towards Ln(III) similar to those of tri-acidic ligands. In the bimetallic Lu2ACX complex, the cations are deeply embedded in the cavity of the ligand, as shown by the X-ray structure. In aqueous solution, the number of water molecules coordinated to the cation in the LnACX complex depends on the nature and concentration of the alkali ions of the supporting electrolyte, as shown by luminescence and relaxometric measurements. There is only one water molecule coordinated in the LnBCX complex, which enables us to highlight an important second sphere contribution to relaxivity. The NMR study of the RAFT peptidic ligand shows the complexation of Ln(III), with an affinity similar to those of natural ligands derived from calmodulin. The relaxometric study also shows an important second sphere contribution to relaxivity. To better understand the intricate molecular factors affecting relaxivity, we developed new relaxometric methods based on probe solutes. These methods allow us to determine the charge of the complex, weak affinity constants, trans-metallation constants, and the electronic relaxation rate. (author)

  14. Transitory and steady analysis of grounding structures using the LN-FDTD method

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Rodrigo Melo e Silva de; Souza Sobrinho, Carlos Leonidas da S. [Federal University of Para (UFPA), Belem, PA (Brazil). Electrical and Computer Engineering Dept.], Emails: rodrigo@lane.ufpa.br, leonidas@ufpa.br

    2007-07-01

    This work presents an overview of the LN-FDTD method (FDTD in local and non orthogonal coordinate system) to solve Maxwell's Equations. This method has been used to simulate curved grounding structures. Results are obtained by employing the presented methodology and they are compared to reference equations available in literature. (author)

  15. STABILIZATION OF POLYANILINE Ftuvts lN THE PRESENCE OF p ...

    African Journals Online (AJOL)

    6(1 }x 27-31(1992). STABILIZATION OF POLYANILINE Ftuvts lN THE PRESENCE OF p-AMiNOPHENOL. DD. Crate, and NF. Osoro, Department of Chemistry. ... v. This severely limits the potential domain in which PAN can be used. Several researchers have assigned the products formed during the degradation to be.

  16. Measurement of bridge body across the river Labe in Mělník

    Directory of Open Access Journals (Sweden)

    Rudolf Urban

    2009-11-01

    Full Text Available Long-span concrete prestressed bridges are sensitive for long-term deflections growing. Bridge over the river Labe near Mělníkis a typical example of this structural type. 15 years after bridge opening, midspan deflection still increases. Detail surveyingof the superstructure was made to identify possible structure failure.

  17. Slow relaxation dynamics of a mononuclear Er(iii) complex surrounded by a ligand environment with anisotropic charge density.

    Science.gov (United States)

    Lim, Kwang Soo; Kang, Dong Won; Song, Jeong Hwa; Lee, Han Geul; Yang, Mino; Hong, Chang Seop

    2017-01-17

    Two sets of isostructural mononuclear compounds, [Ln(LOMe)2(H2O)2](PF6) [1, Ln = Er; 3, Ln = Gd; LOMe = CpCo{P(O)(O(CH3))2}3] and Ln(LOMe)2(NO3) (2, Ln = Er and 4, Ln = Gd), are synthesized by self-assembly of the respective lanthanide ions and tripodal chelate ligands. The Ln ions are encircled by two LOMe ligands, and two water molecules or one nitrate anion. Each octacoordinated Ln center adopts a distorted square antiprism geometry. The Er complex (2) chelated by a nitrate anion shows slow dynamics in magnetic relaxation, diagnostic of a single-ion magnet. Quantum tunneling in 2 is effectively blocked by application of an external field. Weak intermolecular magnetic interactions occur in 2, and are supported by the magnetic behavior of 4. Chemical dilution of Er with the diamagnetic Y ion can nullify magnetic interactions and suppress quantum tunneling. Generation of slow relaxation dynamics in the Er system is related to the anisotropic charge distribution supplied by the coordination of ligands with different charge densities, as observed in the Dy analogue. This suggests that magnetic anisotropy arises in a coordination system when an anisotropic lanthanide ion (Dy and Er) is surrounded by a ligand environment with anisotropic charge density, resulting in slow magnetic relaxation.

  18. A fluorescence study on the complexation of Sm(iii), Eu(iii) and Tb(iii) with tetraalkyldiglycolamides (TRDGA) in aqueous solution, in solid state, and in solvent extraction.

    Science.gov (United States)

    Kou, Fei; Yang, Suliang; Qian, Hongjuan; Zhang, Lihua; Beavers, Christine M; Teat, Simon J; Tian, Guoxin

    2016-11-22

    Tetraalkyldiglycolamide (TRDGA) ligands have potential utilization for the separation of actinide and lanthanide ions in the nuclear industry as chelates in aqueous solution if water-soluble or as extractants in organic solvents if water-insoluble. Here, a spectral titration method is extensively applied to investigating the complexation of fluorescent Sm(iii), Eu(iii), and Tb(iii) with TRDGA ligands in aqueous solutions and a solvent extraction system. In aqueous solutions using N,N,N',N'-tetramethyldiglycolamide (TMDGA, LI) as chelate, three successive complex species of Ln(iii), including [LnLI]3+, [LnL]3+, and [LnL]3+, are identified for each Ln(iii) (Ln = Sm, Eu, and Tb), and their stability constants are determined with fluorescence spectral titration method at 25 °C in 1 M NaNO3. The coordination mode in [LnL]3+ is illustrated by single-crystal structures of the solid compounds LnL(ClO4)3 (Ln = Sm, Eu, Tb, and LI = TMDGA) grown from aqueous solutions by slow evaporation. The crystal structures show that in the complexes Ln(iii) ions are coordinated by nine oxygen atoms from three tridentate LI ligands in a distorted tricapped trigonal prism geometry. To provide parallels to solvent extraction chemistry, the extracted Ln(iii) complexes with N,N'-dimethyl-N,N'-dioctyldiglycolamide (DMDODGA, LII, a lipophilic analogue of TMDGA) are prepared, and the fluorescence spectra are collected as well for comparison. The fluorescence spectra of the extracted Ln(iii) complexes with LII in an organic phase of 40-60% (v/v) n-octanol-kerosene are nearly identical to the corresponding deconvoluted spectra of [LnL]3+ in aqueous solution. The similarity in fluorescence spectra suggests that Ln(iii) ion in the extracted complexes is also coordinated by three tridentate LII ligands and that the nitrate anions acting just as counterions do not directly bond to Ln(iii) in the organic phase of solvent extraction.

  19. Light Lanthanide Complexes with Crown Ether and Its Aza Derivative Which Show Slow Magnetic Relaxation Behaviors.

    Science.gov (United States)

    Wada, Hisami; Ooka, Sayaka; Yamamura, Tomoo; Kajiwara, Takashi

    2017-01-03

    Two sets of isostructural Ln(III) mononuclear complexes, [Ln(NO3)3(18-crown-6)] (Ln = Ce (1), Pr (2), and Nd (3)) and [Ln(NO3)3(1,10-diaza-18-crown-6)] (Ln = Ce (4), Pr (5), and Nd (6)), were synthesized, and their slow magnetic relaxation behavior was investigated. Since Ln(III) ions are located in an axially stressed ligand field in both sets of complexes, they can exhibit single-molecule magnet (SMM) behavior owing to the oblate-type electronic distributions of the ground sublevels found in Ce(III), Pr(III), and Nd(III). Field-induced slow magnetic relaxation was observed for Ce(III) and Nd(III) complexes 1, 3, 4, and 6 under an applied bias dc field of 1000 Oe, whereas no slow relaxation was observed for Pr(III) complexes 2 and 5. The slow magnetic relaxation behavior of 1, 3, 4, and 6 was correlated with the even-numbered Jz sublevels of Ce(III) and Nd(III) ions, known as the Kramers system.

  20. Influencing the size and anion selectivity of dimeric Ln(3+)[15-metallacrown-5] compartments through systematic variation of the host side chains and central metal.

    Science.gov (United States)

    Jankolovits, Joseph; Lim, Choong-Sun; Mezei, Gellert; Kampf, Jeff W; Pecoraro, Vincent L

    2012-04-16

    Dimeric Ln(3+)[15-metallacrown-5] compartments selectively recognize carboxylates through guest binding to host metal ions and intermolecular interactions with the phenyl side chains. A systematic study is presented on how the size, selectivity, and number of encapsulated guests in the dimeric containers is influenced by the Ln(3+)[15-metallacrown(Cu(II))-5] ligand side chain and central metal. Compartments of varying heights were assembled from metallacrowns with S-phenylglycine hydroxamic acid (pgHA), S-phenylalanine hydroxamic acid (pheHA), and S-homophenylalanine hydroxamic acid (hpheHA) ligands. Guests that were examined include the fully deprotonated forms of terephthalic acid, isonicotinic acid, and bithiophene dicarboxylic acid (btDC). X-ray crystallography reveals that the side-chain length constrains the maximum and minimum length guest that can be encapsulated in the compartment. Compartments with heights ranging from 9.7 to 15.2 Å are formed with different phenyl side chains that complex 4.3-9.2 Å long guests. Up to five guests are accommodated in Ln(3+)[15-metallacrown(Cu(II))-5] compartments depending on steric effects from the host side chains. The nine-coordinate La(3+) central metal promotes the encapsulation of multiple guests, while the eight-coordinate Gd(3+) typically binds only one dicarboxylate. Electrospray ionization mass spectrometry reveals that the dimerization phenomenon occurs beyond the solid state, suggesting that these containers can be utilized in solid-state and solution applications. © 2012 American Chemical Society

  1. Preparación y caracterización de óxidos de cobalto Cuasi-bidimensionales Ln1-xSr1+xCoO4 (Ln= La, Nd y Gd

    Directory of Open Access Journals (Sweden)

    Señarís-Rodríguez, M. A.

    2004-08-01

    Full Text Available By using the nitrate decomposition method in the presence of KNO3, we have been able to enlarge the compositional range of the cobaltlayered compounds Ln1-xSr1+xCoO4 (Ln: La, Nd, Gd to 0≤x≤0.40 in the case of lanthanum, to 0≤x≤0.30 for neodymium, and to 0≤x≤0.20 in the case of gadolinium. In this work we present the results of their structural characterization by means of powder X-ray diffraction (PXD and Rietveld analysis as a function of composition (x and the rare earth (Ln, information that has been complemented by infrared spectroscopy (IR, electron diffraction (ED and electron microscopy.Mediante el método de descomposición de nitratos en presencia de KNO3, se ha conseguido aumentar el rango composicional de los compuestos cuasi-bidimensionales de cobalto Ln1-xSr1+xCoO4 (Ln: La, Nd y Gd, a 0≤x≤0.4 cuando Ln = La, 0≤x≤0.3 cuando Ln = Nd y 0≤x≤0.2 cuando Ln = Gd. En este trabajo se presentan los resultados de su caracterización estructural mediante difracción de rayos X en polvo (DRX y análisis Rietveld tanto en función de la composición (x como de la tierra rara (Ln, información que se complementa con datos de espectroscopía de infrarrojo (IR, difracción de electrones (DE y microscopía electrónica (ME.

  2. Thermometry and up-conversion luminescence of Yb(3+)-Er(3+) co-doped Na2Ln2Ti3O10 (Ln = Gd, La) phosphors.

    Science.gov (United States)

    Zhang, Zhiyu; Guo, Chongfeng; Suo, Hao; Zhao, Xiaoqi; Zhang, Niumiao; Li, Ting

    2016-07-28

    Yb(3+)/Er(3+)-ion co-doped Na2Ln2Ti3O10 (Ln = Gd, La) up-conversion (UC) phosphors were successfully synthesized by a sol-gel method, and their crystal structures were characterized by powder X-ray diffraction. Dazzling yellow-greenish light was emitted under the excitation of 980 nm near-infrared (NIR) light, composing green and red emission bands from the (2)H11/2/(4)S3/2→(4)I15/2 and (4)F9/2→(4)I15/2 transitions of Er(3+), respectively. The optimal composition and synthesis parameters were determined according to their UC emission intensity. The photon absorption and emission processes were illustrated based on the UC mechanism, in which energy transfer (ET) from Yb(3+) to Er(3+) plays a pivotal role and has been proved by the variation of green emission lifetime in Er(3+) singly and Yb(3+)/Er(3+) co-doped Na2Ln2Ti3O10 samples. The temperature-dependent fluorescence intensity ratios (FIR) of the two thermal coupled energy level (TCL) emission from (2)H11/2→(4)I15/2 (526 nm) and (4)S3/2→(4)I15/2 (549 nm) were calculated in the range of 290-490 K, and their sensitivity values were approximately 0.0058 K(-1) for Na2Gd2Ti3O10 at 490 K and 0.0061 K(-1) for Na2La2Ti3O10 at 470 K, as potential optical temperature sensor.

  3. Synthesis, structure, and polymorphism of A{sub 3}LnSi{sub 2}O{sub 7} (A=Na, K; Ln=Sm, Ho, Yb)

    Energy Technology Data Exchange (ETDEWEB)

    Latshaw, Allison M.; Yeon, Jeongho; Smith, Mark D.; Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu

    2016-03-15

    Four new members of the A{sub 3}LnSi{sub 2}O{sub 7} family, K{sub 3}SmSi{sub 2}O{sub 7}, Na{sub 3}HoSi{sub 2}O{sub 7}, and two polymorphs of Na{sub 3}YbSi{sub 2}O{sub 7}, are reported. K{sub 3}SmSi{sub 2}O{sub 7} crystallizes in the hexagonal space group P6{sub 3}/mcm, Na{sub 3}HoSi{sub 2}O{sub 7} and Na{sub 3}YbSi{sub 2}O{sub 7} crystallize in the hexagonal space group P6{sub 3}/m, and Na{sub 3}YbSi{sub 2}O{sub 7} crystallizes in the trigonal space group P31c. The Na{sub 3}YbSi{sub 2}O{sub 7} composition that crystallizes in P31c is a new structure type. The magnetic properties for the Ho and Yb analogs are reported. - Graphical abstract: The different structure types and polymorphs of the A{sub 3}LnSi{sub 2}O{sub 7} family reported. - Highlights: • Four new members of the A{sub 3}LnSi{sub 2}O{sub 7} family are presented. • Na{sub 3}YbSi{sub 2}O{sub 7} is reported as two polymorphs, one is a new structure type. • Crystals synthesized out of molten fluoride fluxes.

  4. In situ hydrothermal syntheses, structures and photoluminescent properties of four novel metal-organic frameworks constructed by lanthanide (Ln=Ce(III), Pr(III), Eu(III)) and Cu(I) metals with flexible dicarboxylate acids and piperazine-based ligands

    Science.gov (United States)

    Ay, Burak; Karaca, Serkan; Yildiz, Emel; Lopez, Valerie; Nanao, Max H.; Zubieta, Jon

    2016-01-01

    Four novel metal-organic frameworks,[Cu2Cl2(pyrz)]n (1) and (H2pip)n[Ln2(pydc)4(H2O)2]n (Ln=Ce (2), Pr (3) and Eu (4), H2pzdc=2,3-pyrazinedicarboxylic acid, pyrz=pyrazine, H2pydc=2,6-pyridinedicarboxylic acid, H2pip=piperazine) have been synthesized under hydrothermal conditions and characterized by the elemental analysis, ICP, Far IR (FIR), FT-IR spectra, TGA, single crystal X-ray diffraction analysis and powder X-ray diffraction (PXRD). Compound 1 is two-dimensional containing Cl-Cu-Cl sites, while the lanthanide complexes contain one-dimensional infinite Ln-O-Ln chains. All the complexes show high thermal stability. The complexes 1-3 exhibit luminescence emission bands at 584, 598 and 614 nm at room temperature when excited at 300 nm. Complex 4 exhibits bright red solid-state phosphorescence upon exposure to UV radiation at room temperature.

  5. Windmill-shaped octanuclear Zn/Ln (LnIII = Dy, Tb, Ho) heterometallic ensembles supported by a tetraferrocene scaffold.

    Science.gov (United States)

    Chakraborty, Amit; Goura, Joydeb; Bag, Prasenjit; Bar, Arun Kumar; Sutter, Jean-Pascal; Chandrasekhar, Vadapalli

    2016-11-28

    Utilizing a new ferrocene-based compartmental ligand, H4L (1), a series of novel heterometallic complexes [{LZn(μ-OAc)Dy}4(μ4-H2O)] (2), [{LZn(μ-OAc)Tb}4(μ4-H2O)] (3), [{LZn(μ-OAc)Ho}4(μ4-H2O)] (4), [L = Fe[(C5H4){-C(Me)[double bond, length as m-dash]N-N[double bond, length as m-dash]C6H3-(o-O)(m-O)}]2] were synthesized and characterized. 2 and 3 crystallize in the monoclinic crystal system in the I2/m space group, whereas 4 crystallizes in the tetragonal crystal system in the I4/m space group. The tetra deprotonated ligand L4- has two distinct coordination compartments: one pocket (2N, 2O) suitable for the transition metal (3d) ions and another pocket (4O) suitable for lanthanide (4f) metal ions. Additionally, the terminal phenoxo group can be utilized for cluster expansion. In all the complexes, the ZnII ion is in a perfect square pyramidal (2N, 3O) geometry whereas the lanthanide ion has a coordination number of eight (8O) in a distorted biaugmented trigonal-prism geometry. The electrochemical properties of 2 and 3 along with ligand H4L (1) were studied by cyclic voltammetry (CV). All the complexes display a similar type of electrochemical behavior viz., one quasi-reversible oxidation typical of a ferrocene/ferrocenium motif. The magnetic properties of all the complexes have also been investigated.

  6. Cationic rare-earth metal SALEN complexes.

    Science.gov (United States)

    Liu, Qiancai; Meermann, Christian; Görlitzer, Hans W; Runte, Oliver; Herdtweck, Eberhardt; Sirsch, Peter; Törnroos, Karl W; Anwander, Reiner

    2008-11-28

    Complexes (Salpren(tBu,tBu))Y[N(SiHMe2)2](thf) and (SALEN(tBu,tBu))La[N(SiHMe2)2](thf) (SALEN(tBu,tBu) = Salcyc(tBu,tBu) and Salpren(tBu,tBu)) were prepared from Ln[N(SiHMe2)2]3(thf)2 and H2SALEN(tBu,tBu). The yttrium complex was characterized by X-ray crystallography revealing intrinsic solid-state structural features: the metal centre is displaced by 1.05 angstroms from the [N2O2] least squares plane of a highly bent Salpren(tBu,tBu) ligand (angle(Ph,Ph) dihedral angle of 80.4(1) degrees ) and is coordinated asymmetrically by the silylamide ligand exhibiting one significant Y---(HSi) beta-agostic interaction (Y-N1-Si1, 106.90(9) degrees; Y---Si1, 3.2317(6) angstroms). Complexes (SALEN(tBu,tBu))Ln[N(SiHMe2)2](thf)n (n = 1, Sc; n = 2, Y, La) react with ammonium tetraphenylborate to form the ion pairs [(SALEN(tBu,tBu))Ln(thf)n][BPh4]. The cationisation was proven by X-ray crystal structure analyses of [(Salpren(tBu,tBu))Sc(thf)2][B(C6H5)4].2(thf) and [(Salpren(tBu,tBu))Ln(thf)3][B(C6H5)4].4(thf) (Ln = Y, La), showing an octahedral and pentagonal-bipyramidal coordination geometry, respectively.

  7. NIR luminescence of 2-(2,2,2-trifluoroethyl)-1-indone (TFI) neodymium and ytterbium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weizuo; Li, Jingya; Li, Hongfeng; Yan, Pengfei; Hou, Guangfeng; Li, Guangming, E-mail: gmli_2000@163.com

    2014-02-15

    Two series of six β-diketone, 2-(2,2,2-trifluoroethyl)-1-indone (TFI) containing a trifluorinated alkyl group and a rigid indone group, neodymium and ytterbium complexes, namely, [Ln(TFI){sub 3}L] [Ln=Nd; L=(H{sub 2}O){sub 2} (1), bpy (2) and phen (3); Ln=Yb; L=(H{sub 2}O){sub 2} (4), bpy (5) and phen (6); bpy=2,2-bipyridine, phen=1,10-phenanthroline], have been synthesized and isolated. X-ray crystallographic analysis reveals that complex 2 is mononuclear structure in which the central Nd{sup 3+} ion is eight-coordinated by six oxygen atoms furnished by three TFI ligands and two nitrogen atoms from ancillary ligand. PXRD analysis suggests that all complexes 1 and 4, 2 and 5, 3 and 6 are isomorphic, respectively The room-temperature PL spectra of complexes 1–6 show strong characteristic NIR luminescence of the corresponding Nd{sup 3+} and Yb{sup 3+} ions and the substitution of the solvent molecules by bidentate nitrogen ligands essentially enhance the NIR luminescence quantum yields and lifetimes of the complexes. -- Highlights: • Two series of six β-diketone (TFI) lanthanide complexes have been isolated. • NIR luminescence of the six lanthanide complexes has been investigated. • Intramolecular energy transfer between ligands and Ln{sup 3+} (Ln=Nd, Yb) ions are studied.

  8. Sellmeier equations, group velocity dispersion, and thermo-optic dispersion formulas for CaLnAlO4 (Ln = Y, Gd) laser host crystals.

    Science.gov (United States)

    Loiko, Pavel; Becker, Petra; Bohatý, Ladislav; Liebald, Christoph; Peltz, Mark; Vernay, Sophie; Rytz, Daniel; Serres, Josep Maria; Mateos, Xavier; Wang, Yicheng; Xu, Xiaodong; Xu, Jun; Major, Arkady; Baranov, Alexander; Griebner, Uwe; Petrov, Valentin

    2017-06-15

    We studied the refractive index and dispersive properties of the tetragonal rare-earth calcium aluminates, CaLnAlO4 (Ln=Gd or Y). Sellmeier equations were derived for the spectral range of 0.35-2.1 μm. The group velocity dispersion (GVD) in CaGdAlO4 is positive at ∼1  μm, 95  fs2/mm and negative at ∼2  μm, -40  fs2/mm. The GVD values for CaYAlO4 are similar. In addition, thermo-optic coefficients, dn/dT, and thermal coefficients of the optical path were determined for CaYAlO4. dn/dT is negative at ∼1  μm, dno/dT=-7.8, and dne/dT=-8.7×10-6  K-1. Thermo-optic dispersion formulas were constructed. The obtained data are of key importance to the design of high-power mode-locked oscillators at ∼1 and ∼2  μm based on such laser hosts.

  9. Oxalic Acid-Assisted Hydrothermal Synthesis and Luminescent of Hexagonal NaYF4:Ln3+ (Ln = Sm, Eu, Yb/Er Micro/Nanoplates

    Directory of Open Access Journals (Sweden)

    Feng Tao

    2017-01-01

    Full Text Available Hexagonal NaYF4:Ln3+ micro/nanoplates were successfully synthesized via a hydrothermal method using oxalic acid as a shape modifier. X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, and selected area electron diffraction (SAED have been used to study the morphologies and crystal structure of the products. The effects of the pH values and the molar ratio of oxalic acid to NaOH on the crystal growth have been investigated in detail. The time-dependent experiments have been conducted to investigate the morphology evolution process, and based on the results, a possible growth mechanism was proposed. The photoluminescence properties of 5 mol% Eu3+ and 3 mol% Sm3+ doped NaYF4 and 20 mol% Yb3+/2 mol% Er3+ codoped NaYF4 micro/nanoplates were investigated. The experimental results showed that NaYF4:Ln3+ micro/nanoplates have excellent luminescence and can be potential application in the field of light display systems, lasers, and optoelectronic devices.

  10. Mono(pyridine-N-oxide) analog of DOTA as a suitable organic reagent for a sensitive and selective fluorimetric determination of Ln(III) ions

    Energy Technology Data Exchange (ETDEWEB)

    Vanek, Jakub [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Lubal, Premysl, E-mail: lubal@chemi.muni.cz [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Sevcikova, Romana [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Polasek, Miloslav; Hermann, Petr [Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40, Prague (Czech Republic)

    2012-08-15

    The mono(pyridine-N-oxide) analog of the H{sub 4}dota macrocylic ligand, H{sub 3}do3a-py{sup NO}, is capable of forming thermodynamically stable and kinetically inert Ln(III) complexes. Its Eu(III) and Tb(III) complexes display a strong long-lived fluorescence as a result of the antenna effect of the pyridine-N-oxide fluorophore in the reagent. It is shown that H{sub 3}do3a-py{sup NO} can be used as a fluorogenic reagent for the determination of Eu(III) and Tb(III) at pH 6.5 and c{sub L}=1 mM. At an excitation wavelength of 286 nm, the emission maxima are 615 nm (Eu(III)-complex), and 547 nm (Tb(III)complex). Detection limits are at concentrations around 1.0 {mu}M and linearity of the method spans over 2 orders of magnitude. The method was applied to artificial and real samples (spiked mineral waters, extracts from cathode ray tube luminophore dust) and gave satisfactory results. The method is simple, rapid, and hardly interfered by other metal ions. - Graphical Abstract: A DOTA-like ligand with pyridine-N-oxide pendant arm is used for a quick, selective and sensitive determination of Eu{sup 3+} and Tb{sup 3+} ions through sensitized emission with excitation at 286 nm. The presented fluorimetric method is not interfered by transition metal or other lanthanide(III) ions and has a high dynamic range. Highlights: Black-Right-Pointing-Pointer Quick, selective and sensitive determination of Eu{sup 3+}/Tb{sup 3+} ions was developed. Black-Right-Pointing-Pointer Sensitized emission with excitation at 286 nm through pyridine-N-oxide pendant arm. Black-Right-Pointing-Pointer No interference of transition metal or other Ln(III) ions within high dynamic range.

  11. N2 gas egress from patients' airways during LN2 spray cryotherapy.

    Science.gov (United States)

    O'Connor, John P; Hanley, Brian M; Mulcahey, Thomas I; Sheets, Ellen E; Shuey, Kacey W

    2017-06-01

    Spray cryotherapy using liquid nitrogen (LN2) is a general surgical tool used to ablate benign or malignant lesions. Adequate egress of the gaseous nitrogen (N2) generated during this process must be provided for safe use when LN2 is used within the body rather than topically. When delivered to either the gastrointestinal tract (requiring active venting via a suction tube) or body cavities open to room barometric pressure (such as lung airways) allowing for passive venting, the N2 gas generated from the boiling process must be evacuated. This work will examine the egress of N2 during procedures requiring passive venting from human airways undergoing liquid nitrogen spray cryotherapy. Venting characteristics for safe N2 egress will be presented and discussed based on analytical modeling using fluid mechanics simulations and experimental studies of N2 venting with laboratory and porcine models. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  12. Hardness of Carburized Surfaces in 316LN Stainless Steel after Low Temperature Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Byun, TS

    2005-01-31

    A proprietary surface carburization treatment is being considered to minimize possible cavitation pitting of the inner surfaces of the stainless steel target vessel of the SNS. The treatment gives a large supersaturation of carbon in the surface layers and causes substantial hardening of the surface. To answer the question of whether such a hardened layer will remain hard and stable during neutron irradiation, specimens of the candidate materials were irradiated in the High Flux Isotope Reactor (HFIR) to an atomic displacement level of 1 dpa. Considerable radiation hardening occurred in annealed 316LN stainless steel and 20% cold rolled 316LN stainless steel, and lesser radiation hardening in Kolsterised layers on these materials. These observations coupled with optical microscopy examinations indicate that the carbon-supersaturated layers did not suffer radiation-induced decomposition and softening.

  13. FItness programy a individuální přístup ve fitness

    OpenAIRE

    Rambous, Milan

    2008-01-01

    Souhrn: Tato diplomová práce se zabývá problematikou fitness programů a individuálru'ho přístupu ve fitness centrech. Celé téma zahrnuje rozpracování postupu při vytváření fitness programů a roli osobního trenéra ve fitness. Dále jsou zde uvedeny specifika některých fitness programů a v empirické části pak příklad dvou individuálních fitness programů. Název práce: Fitness programy a individuálnípřístup ve fitness Title: FITNESS PROGRAMS AND INDIVIDUAL CARE IN FITNESS Cíle práce: 1. podrobný p...

  14. Equipping an FPGA-Based Mars Rover With an LN-200 IMU

    Science.gov (United States)

    Zola, Nicholas J.

    2005-01-01

    The Mars Exploration Rovers (MER) currently navigating the surface of Mars are outfitted with an advanced stereovision correlation algorithm which allows them to "see" three-dimensionally and autonomously avoid obstac'les in their path. A bottleneck of this system is that it is computationally intense and requires 3 minutes of processing for every correlated image and path choice. Taking advantage of the optimization and reprogrammability of FPGAs, the Mobility Avionics lab has reduced this process to under a second. The lab is demonstrating the advancement with a prototype rover, complete with an LN-200 inertial measurement unit (IMU), which is a flight spare from MER. The LN-200 is a space-grade, six degrees-of-freedom IMU using three fiber-optic gyroscopes and three silicon accelerometers and no moving parts. It has particular power-sequencing needs and communicates with a specialized serial protocol (SDLC over RS-422), requiring specific hardware and software for proper functionality and interfacing with an FPGA. The process of incorporating the LN-200 into the system is described herein.

  15. Výroba dentálních náhrad

    OpenAIRE

    Lekeš, Jonáš

    2013-01-01

    Tato práce popisuje části dentálních náhrad, lékařské pojmy, které se s nimi vážou a vysvětluje proces a problematiku koncepce a výroby těchto částí. Různé druhy biomateriálů jako kovy, keramika, polymery či kompozity jsou zde popsány, hlavní důraz je však kladen na titanové a chrom kobaltové slitiny a korozivzdorné oceli. Experimentální část nabízí 2 řešení zlepšení výroby součásti. První část experimentální části se zabývá zlepšením kvality styčné plochy pilíře zvýšením hustoty síťování sou...

  16. Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels

    Science.gov (United States)

    Ningshen, S.; Kamachi Mudali, U.

    2010-03-01

    The pitting and intergranular corrosion (IGC) resistance of AISI type 301LN stainless steels were evaluated using ASTM methods, anodic polarization, and electrochemical impedance techniques. The IGC results indicated that the microstructure of the samples after sensitization heat treatment at 675 °C for 1 h shows step or dual structure for both imported and indigenous materials indicating insignificant Cr23C6 precipitation. The results of immersion tests in boiling 6% copper sulfate + 16% sulfuric acid + copper solution for 24 h followed by the bend test (ASTM A262 Practice-E method) indicated no crack formation in any of the tested specimens. Pitting corrosion resistance carried out in 6% FeCl3 solution at different temperatures of 22 ± 2 and 50 ± 2 °C (ASTM G 48) up to the period of 72 h revealed pitting corrosion attack in all the investigated alloys. The potentiodynamic anodic polarization results in 0.5 M NaCl revealed variation in passive current density and pitting potential depending on the alloy chemistry and metallurgical condition. The passive film properties studied by electrochemical impedance spectroscopy (EIS) correlated well with the polarization results. The x-ray diffraction (XRD) results revealed the presence of austenite (γ) and martensite (α') phases depending on the material condition. The suitability of three indigenously developed AISI type 301LN stainless steels were compared with imported type 301LN stainless steel and the results are highlighted in this article.

  17. SYMBOLISM OF THE COLOR NAMES IN THE STORY THE WALL BY L.N. ANDREYEV

    Directory of Open Access Journals (Sweden)

    Vladislav Sergeevitch Morschinsky

    2017-03-01

    Full Text Available Purpose: this article is devoted to the linguocultural study of peculiarities of the of color terms functioningin the story The Wall by L.N. Andreyev. The author aims to identify the functions of coloration in the literary text, as well as their correlation with one of the symbolic groups that implement the opposition «life – death». Methodology: in addition to the traditional descriptive and comparative methods, as well as elements of the component analysis, the method of linguoculturological interpretation was applied that allows to determine the correlation between language and culture in the implementation of the coloration functions in the work by Leonid Andreyev. Results: it was found that color terms, functioning in the story The Wall by L.N. Andreyev carry a symbolic function as well as implement the opposition «life – death» within the symbolic opposition framework, the former being fundamental in both ethno-cultural and author’s artistic world view. Practical implications: the results of this study can be usedat both the university and school while studying works by L.N. Andreyev, as well as performing integrative linguistic and cultural studies.

  18. Interplay between 3d-3d and 3d-4f interactions at the origin of the magnetic ordering in the Ba2LnFeO5 oxides

    Science.gov (United States)

    Kundu, Asish K.; Hardy, Vincent; Caignaert, Vincent; Raveau, Bernard

    2015-12-01

    A new family of oxides in which 3d-3d and 3d-4f interactions are of comparable strength has been synthesized and characterized both from structural and physical viewpoints. These compounds of formulation Ba2LnFeO5 (Ln  =  Sm, Eu, Gd, Dy, Ho, Er, Yb) are isotypic to the perovskite derivative Ba2YFeO5. They exhibit an original structure consisting of isolated FeO4 tetrahedra linked via LnO6 (or YO6) octahedra. Magnetic and calorimetric measurements show that all these compounds exhibit a unique, antiferromagnetic transition involving both the 3d and 4f ions. The antiferromagnetic properties of the Ln  =  Y phase (non-magnetic Y3+) and of the Ln  =  Eu (non-magnetic ground state multiplet of Eu3+) are ascribed to super-super exchange Fe-O-O-Fe interactions, leading to the lowest T N (5.5 K for Y and 4.6 K for Eu). The introduction of a magnetic lanthanide, i.e. Ln  =  Sm, Gd, Dy, Ho, Er, Yb, in the octahedral sites, leads to larger T N values (up to 9.8 K for Ln  =  Yb). It is found that several mechanisms must be taken into account to explain the complex evolution of the magnetic properties along the Ba2LnFeO5 series. In particular, the super-exchange Ln-O-Fe, as well as the on-site Ln3+ magnetocrystalline anisotropy, are suggested to play crucial roles. This Ba2LnFeO5 series offers a rare opportunity to investigate experimentally a situation where the 3d-3d and 3d-4f interactions co-operate on an equal footing to trigger a unique long-range magnetic ordering in insulating oxides.

  19. The Laser Welding with Hot Wire of 316LN Thick Plate Applied on ITER Correction Coil Case

    CERN Document Server

    Fang, Chao; Wu, Weiyue; Wei, Jing; Zhang, Shuquan; Li, Hongwei; Dolgetta, N; Libeyre, P; Cormany, C; Sgobba, S

    2014-01-01

    ITER correction coil (CC) cases have characteristics of small cross section, large dimensions, and complex structure. The cases are made of heavy thick (20 mm), high strength and high toughness austenitic stainless steel 316LN. The multi-pass laser welding with hot wire technology is used for the case closure welding, due to its low heat input and deformation. In order to evaluate the reliability of this welding technology, 20 mm welding samples with the same groove structure and welding depth as the cases were welded. High purity argon was used as the shielding gas to prevent oxidation because of the narrowness and depth of the weld. In this paper investigation of, microstructure characteristics and mechanical properties of welded joints using optimized welding parameters are presented. The results show that the base metal, fusion metal, and heat affected zone (HAZ) are all have fully austenitic microstructure, and that the grain size of fusion metal was finer than that of the base metal. The welding resulte...

  20. Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP-102 D, KP-102 LN, KP-102D, KP-102LN.

    Science.gov (United States)

    2004-01-01

    Pralmorelin [GPA 748, GHRP 2, growth hormone-releasing peptide 2, KP-102 D, KP 102 LN] is an orally active, synthetic growth hormone-releasing peptide from a series of compounds that were developed by Polygen in Germany and Tulane University in the US. Researchers at Tulane University led by Dr Cyril Bowers synthesised a series of small highly active peptides ranging in size from 3-5 amino acids or partial peptides that were suitable for a variety of administration formats (subcutaneous, buccal, oral, depot). These peptides mimic the actions of ghrelin, a 28 amino acid octanoyl peptide that regulates the release of growth hormone (GH), and may play an important role in bone and muscle growth, food intake and possibly improve recovery from injury. The use of pralmorelin as a diagnostic agent for GH deficiency is based on its ability to markedly increase plasma levels of GH in healthy subjects irrespectively of gender, obesity or age. However, in patients with GH deficiency, the effect of pralmorelin on GH levels is significantly lower compared with healthy controls. Analysis of the receiver-operating characteristics curve provided the cut-off threshold value for the GH peak of 15.0 micro g/L for the identification of patients with GH deficiency from those of healthy controls. Kaken acquired worldwide manufacturing and marketing rights to pralmorelin, and then sublicensed it to Wyeth (formerly American Home Products) for the US and Canada. Kaken retains rights to pralmorelin in Japan. On 11 March 2002 American Home Products changed its name and the names of its subsidiaries Wyeth-Ayerst and Wyeth Lederle to Wyeth. Kaken also granted exclusive sublicense options in Africa, Australia, Europe, Latin America and New Zealand to unspecified partners. Pralmorelin as KP-102 D [KP-102D] is currently awaiting approval in Japan as a diagnostic agent for hypothalamo-pituitary function. It is planned to be launched in Japan for this indication in 2004. Pralmorelin is also

  1. Synthesis, Structure, and Reactivity of Rare-Earth Metallocene η3-Propargyl/Allenyl Complexes

    NARCIS (Netherlands)

    Quiroga Norambuena, Victor F.; Heeres, André; Heeres, Hero J.; Meetsma, Auke; Teuben, Jan H.; Hessen, Bart

    2008-01-01

    The reaction of the alkyl complexes Cp*2LnCH(SiMe3)2 (Ln = Y, Ce, La; Cp* = η5-C5Me5) and Me2Si(η5-C5Me4)2LnCH(SiMe3)2 (Ln = Ce) with 1-methylalk-2-ynes CH3C≡CR (R = Me 3a, Et 3b, nPr 3c, tBu 3d, SiMe3 3e, Ph 3f, C6H4Me-2 3g, C6H3Me2-2,6 3h, C6H3iPr2-2,6 3i, C6F5 3j) affords the corresponding

  2. ''114''-type nitrides LnAl(Si{sub 4-x}Al{sub x})N{sub 7}O{sub δ} with unusual [AlN{sub 6}] octahedral coordination

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Saifang; Ouyang, Xin [School of Materials Science and Technology, China University of Geosciences, Beijing (China); Department of Chemical and Materials Engineering, University of Auckland (New Zealand); Huang, Zhaohui; Fang, Minghao; Liu, Yan-gai [School of Materials Science and Technology, China University of Geosciences, Beijing (China); Cao, Peng; Gao, Wei [Department of Chemical and Materials Engineering, University of Auckland (New Zealand); Zujovic, Zoran; Soehnel, Tilo [School of Chemical Sciences, University of Auckland (New Zealand); Price, Jason R. [Australian Synchrotron, Clayton, VIC (Australia); Avdeev, Maxim [Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Que, Meidan [School of Electronic and Information Engineering, Xi' an Jiaotong University (China); Suzuki, Furitsu; Kido, Tsuyoshi; Kaji, Hironori [Institute for Chemical Research, Kyoto University (Japan)

    2017-03-27

    Aluminum-nitrogen six-fold octahedral coordination, [AlN{sub 6}], is unusual and has only been seen in the high-pressure rocksalt-type aluminum nitride or some complex compounds. Herein we report novel nitrides LnAl(Si{sub 4-x}Al{sub x})N{sub 7}O{sub δ} (Ln=La, Sm), the first inorganic compounds with [AlN{sub 6}] coordination prepared via non-high-pressure synthesis. Structure refinements of neutron powder diffraction and single-crystal X-ray diffraction data show that these compounds crystallize in the hexagonal Swedenborgite structure type with P6{sub 3}mc symmetry where Ln and Al atoms locate in anticuboctahedral and octahedral interstitials, respectively, between the triangular and Kagome layers of [SiN{sub 4}] tetrahedra. Solid-state NMR data of high-purity La-114 powders confirm the unusual [AlN{sub 6}] coordination. These compounds are the first examples of the ''33-114'' sub-type in the ''114'' family. The additional site for over-stoichiometric oxygen in the structure of 114-type compounds was also identified. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Chemical bond properties and charge transfer bands of O(2-)-Eu(3+), O(2-)-Mo(6+) and O(2-)-W(6+) in Eu(3+)-doped garnet hosts Ln3M5O12 and ABO4 molybdate and tungstate phosphors.

    Science.gov (United States)

    Liu, Xiaoguang; Li, Ling; Noh, Hyeon Mi; Moon, Byung Kee; Choi, Byung Chun; Jeong, Jung Hyun

    2014-06-21

    Charge transfer (CT) energy from the ligand to the central ions is an important factor in luminescence properties for rare earth doped inorganic phosphors. The dielectric theory of complex crystals was used to calculate chemical bond properties. Combining the photoluminescence and the dielectric theory of complex crystals, the CT bands of O(2-)-Eu(3+), O(2-)-Mo(6+) and O(2-)-W(6+) for Eu(3+)-doped inorganic phosphors have been investigated experimentally and theoretically. Taking Eu(3+)-doped Ln3M5O12 (Ln = Y, Lu and M = Al, Ga), Gd3Ga5O12, MMoO4 (M = Ca, Sr, Ba) and MWO4 (M = Ca, Sr, Ba) as typical phosphors, we investigated the effects of the cation size on the CT bands and chemical bond properties including the bond length (d), the covalency (fc), the bond polarizability (αb) and the environmental factor (he) of O(2-)-Eu(3+), O(2-)-Mo(6+) and O(2-)-W(6+), respectively. For systematic isostructural Ln3M5O12 (Ln = Y, Lu and M = Al, Ga) phosphors, with the increasing M ion radius, the bond length of Ln-O decreases, but fc and αb increase, which is the main reason that the environmental factor increased. For the isostructural MMoO4:Eu, with the increasing M ion radius, the Mo-O bond length increases, but fc and αb decrease, and thus he decreases. However, in the compound system MWO4:Eu (M = Ca, Ba) with the increasing M ion radius, the O-W bond length increases, but fc and αb increase, and thus he increases and the O-W CT energy decreases. Their O(2-)-Eu(3+), O(2-)-Mo(6+) and O(2-)-W(6+) CT bands as well as their full width at half maximum (FWHM) were directly influenced by he. And with the increasing he, CT bands of O-Eu or O-Mo or O-W decrease and their FWHM increases. These results indicate a promising approach for changing the material properties, searching for new Eu(3+) doped molybdate, tungstate or other oxide phosphors and analyzing the experimental result.

  4. Six new 3d-4f heterometallic coordination polymers constructed from pyrazole-bridged Cu(II)Ln(III) dinuclear units.

    Science.gov (United States)

    Yang, Ting-Hai; Silva, Ana Rosa; Shi, Fa-Nian

    2013-10-14

    Reactions of lanthanide chlorides, copper hydroxycarbonate and 3,5-pyrazole dicarboxylic acid (H3pdc) under hydrothermal conditions result in six new 3d-4f heterometallic coordination polymers with two types of structures. Compounds [CuLn2(pdc)2(Hpdc)(H2O)4]·2H2O (Ln = Tb (1), Dy (2), Er (3), and Y (4) exhibit a layered porous structure, made up of Cu(II)Ln(III) di-nuclear units which are connected by protonated Hpdc(2-) ligand, while the others [Cu3Ln4(pdc)6(H2O)8] (Ln = Eu (5), Gd (6)) display a three-dimensional (3-D) framework structure, in which six Cu(II)Ln(III) di-nuclear units are cross-linked by two coordinated lanthanide atoms. The catalytic properties of 3 are investigated showing its activity and recyclability in the reaction of cyclopropanation of styrene.

  5. Complexing mechanism of the lanthanide cations Eu3+, Gd3+, and Tb3+ with 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (dota)-characterization of three successive complexing phases: study of the thermodynamic and structural properties of the complexes by potentiometry, luminescence spectroscopy, and EXAFS.

    Science.gov (United States)

    Moreau, Juliette; Guillon, Emmanuel; Pierrard, Jean-Claude; Rimbault, Jean; Port, Marc; Aplincourt, Michel

    2004-10-11

    Complexation of the lanthanides Eu3+, Gd3+, and Tb3+ with 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (dota) has been studied in solution by using potentiometry, luminescence spectrometry, and EXAFS. Three series of successive complexes were characterized by at least two of these methods: the immediate [LnHn(dota)](n-1)+** and intermediate [LnHn(dota)](n-1)+* complexes with 0 potentiometry. From the results, a complexation mechanism involving three steps has been proposed. In the [LnHn(dota)](n-1)+** complexes that are instantaneously formed, the lanthanide is bound to four oxygen atoms of the carboxylate groups and to five water molecules. These species evolve rapidly: the lanthanide moves into the macrocycle cavity, two new bonds are formed with two nitrogen atoms diametrically opposed in the tetraaza cycle and only three water molecules remain bound to the lanthanide in the [LnHn(dota)](n-1)+* (0 complexes, which appear after a two-day wait. These compounds are stable for about four days. After 4-8 weeks, a concerted rearrangement occurs which leads to the formation of thermodynamically stable [Ln(dota)]- complexes in which the lanthanide is bound to four nitrogen atoms, four carboxylate oxygen atoms, and one water molecule.

  6. Ultrasound and Microwave Coassisted Synthesis and Luminescent Properties of (Ln = La, Gd; Phosphors

    Directory of Open Access Journals (Sweden)

    Jing Hu

    2013-01-01

    Full Text Available In order to control reaction temperature and reduce processing time, a new method of ultrasound irradiation with microwave heating was used to synthesize (Ln = La, Gd; phosphors at only 80°C in 30 minutes. Their crystal structures and morphologies which have been verified by X-ray diffraction (XRD and scanning electron microscopy (SEM exhibited gradual changes due to the insertion of lanthanide ions (La or Gd in calcium molybdates. Codoping of lanthanum ions ( would enhance the emission intensities that were supported by fluorescent spectrophotometry (FL.

  7. Design and validation of the high performance and low noise CQU-DTU-LN1 airfoils

    DEFF Research Database (Denmark)

    Cheng, Jiangtao; Zhu, Wei Jun; Fischer, Andreas

    2014-01-01

    objective, such as airfoil lift coefficient, drag coefficient and lift-drag ratio, and minimizes trailing edge noise as a constraint. To express airfoil shape, an analytical expression is used. One of the main advantages of the present designmethod is that it produces a highly smooth airfoil shape that can...... emission between the CQU-DTU-LN118 airfoil and the National Advisory Committee for Aeronautics (NACA) 64618 airfoil, which is used in modern wind turbine blades, are carried out. Copyright © 2013 John Wiley & Sons, Ltd....

  8. Agreement Between a Smartphone Pulse Sensor Application and Electrocardiography for Determining lnRMSSD.

    Science.gov (United States)

    Esco, Michael R; Flatt, Andrew A; Nakamura, Fábio Y

    2017-02-01

    Esco, MR, Flatt, AA, and Nakamura, FY. Agreement between a smartphone pulse sensor application and electrocardiography for determining lnRMSSD. J Strength Cond Res 31(2): 380-385, 2017-The purpose of this study was to determine the agreement between a smartphone pulse finger sensor (SPFS) and electrocardiography (ECG) for determining ultra-short-term heart rate variability in 3 different positions. Thirty college-aged men (n = 15) and women (n = 15) volunteered to participate in this study. Sixty-second heart rate measures were simultaneously taken with the SPFS and ECG in supine, seated, and standing positions. The log transformed root mean square of successive R-R interval differences (lnRMSSD) was calculated from the SPFS and ECG. The lnRMSSD values were 81.5 ± 11.7 using ECG and 81.6 ± 11.3 using SPFS (p = 0.63, Cohen's d = 0.01) in the supine position, 76.5 ± 8.2 using ECG and 77.5 ± 8.2 using SPFS (p = 0.007, Cohen's d = 0.11) in the seated position, and 66.5 ± 9.2 using ECG and 67.8 ± 9.1 using SPFS (p < 0.001, Cohen's d = 0.15) in the standing position. The SPFS showed a possibly strong correlation to the ECG in all 3 positions (r values from 0.98 to 0.99). In addition, the limits of agreement (constant error ± 1.98 SD) were -0.13 ± 2.83 for the supine values, -0.94 ± 3.47 for the seated values, and -1.37 ± 3.56 for the standing values. The results of the study suggest good agreement between the SPFS and ECG for measuring lnRMSSD in supine, seated, and standing positions. Although significant differences were noted between the 2 methods in the seated and standing positions, the effect sizes were trivial.

  9. Plumbagin Alleviates Capillarization of Hepatic Sinusoids In Vitro by Downregulating ET-1, VEGF, LN, and Type IV Collagen

    Directory of Open Access Journals (Sweden)

    Guiyu Li

    2017-01-01

    Full Text Available Critical roles for liver sinusoidal endothelial cells (LSECs in liver fibrosis have been demonstrated, while little is known regarding the underlying molecular mechanisms of drugs delivered to the LSECs. Our previous study revealed that plumbagin plays an antifibrotic role in liver fibrosis. In this study, we investigated whether plumbagin alleviates capillarization of hepatic sinusoids by downregulating endothelin-1 (ET-1, vascular endothelial growth factor (VEGF, laminin (LN, and type IV collagen on leptin-stimulated LSECs. We found that normal LSECs had mostly open fenestrae and no organized basement membrane. Leptin-stimulated LSECs showed the formation of a continuous basement membrane with few open fenestrae, which were the features of capillarization. Expression of ET-1, VEGF, LN, and type IV collagen was enhanced in leptin-stimulated LSECs. Plumbagin was used to treat leptin-stimulated LSECs. The sizes and numbers of open fenestrae were markedly decreased, and no basement membrane production was found after plumbagin administration. Plumbagin decreased the levels of ET-1, VEGF, LN, and type IV collagen in leptin-stimulated LSECs. Plumbagin promoted downregulation of ET-1, VEGF, LN, and type IV collagen mRNA. Altogether, our data reveal that plumbagin reverses capillarization of hepatic sinusoids by downregulation of ET-1, VEGF, LN, and type IV collagen.

  10. Lattice energies and polarizabilities of lanthanide gallium garnets (Ln{sub 3}Ga{sub 5}O{sub 12})

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, Dimitar, E-mail: petrov_d_n@abv.bg [Department of Physical Chemistry, University of Plovdiv “Paisii Hilendarski”, 24, Tsar Asen Str., 4000 Plovdiv (Bulgaria)

    2013-04-10

    Highlights: ► The lattice energies Δ{sub L}H{sup θ} of Ln{sub 3}Ga{sub 5}O{sub 12} are determined by the Born–Haber cycle. ► The Born–Haber cycle yields the lowest values among three applied methods. ► Molar polarizations P{sub m} of Ln{sub 3}Ga{sub 5}O{sub 12} have been calculated by the Debye equation. ► The derivative (∂Δ{sub L}H{sup θ}/∂P{sub m}) corresponds to the shear moduli of these crystals. - Abstract: Lattice energies Δ{sub L}H{sup θ} of lanthanide gallium garnets Ln{sub 3}Ga{sub 5}O{sub 12} (Ln = Nd–Lu) have been determined from the Born–Haber thermochemical cycle and compared with those previously obtained by atomistic simulations in the Born model or calculated by an empirical equation. The Born–Haber cycle yields the lowest values among the three methods. Molar polarizations P{sub m} of Ln{sub 3}Ga{sub 5}O{sub 12} have been calculated by the Debye equation. It has been found that the partial derivative (∂Δ{sub L}H{sup θ}/∂P{sub m}) corresponds by magnitude to the shear moduli of these crystals.

  11. The Uncommon Channel-Based Ln-MOFs for Highly Selective Fe3+Detection and Superior Rhodamine B Adsorption.

    Science.gov (United States)

    Xing, Shanghua; Bing, Qiming; Song, Lifei; Li, Guanghua; Liu, Jingyao; Shi, Zhan; Feng, Shouhua; Xu, Ruren

    2016-11-02

    Two new isostructural 3D lanthanide-organic frameworks [H 2 N(Me) 2 ] [Ln 3 (OH)(bpt) 3 (H 2 O) 3 ] (DMF) 2 ⋅(H 2 O) 4 (1-Ln; Ln=Sm and Eu) with a 1D channel (25 Å) have been successfully assembled from the rare trinuclear [Ln 3 (OH)(COO) 9 ] clusters and biphenyl-3,4',5-tricarboxylic acid (H 3 bpt) and exhibit high stability towards water in the pH range 3-10. MOF 1-Eu is a promising luminescent probe for sensing Fe 3+ in aqueous solution and is also selective towards rhodamine B (RhB) with a superior adsorption capacity of 735 mg g -1 , which is the highest among the reported Ln-MOFs for RhB removal so far. Periodic DFT calculations further confirmed the selective adsorption of rhodamine B over other dyes. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. DEHP complexes of lanthanides(III) and actinides(III)

    Energy Technology Data Exchange (ETDEWEB)

    Suglobov, D.N. (V.G. Khlopin Radium Institute, Shvernic Str. 28, 194021 St. Petersburg, (Russian Federation)); Trifonov, Yu.I. (V.G. Khlopin Radium Institute, Shvernic Str. 28, 194021 St. Petersburg, (Russian Federation)); Legin, E.K. (V.G. Khlopin Radium Institute, Shvernic Str. 28, 194021 St. Petersburg, (Russian Federation)); Tutov, A.G. (V.G. Khlopin Radium Institute, Shvernic Str. 28, 194021 St. Petersburg, (Russian Federation))

    1994-10-01

    Lanthanides di-(2-ethylhexyl)phosphates (LnA[sub 3]) crystallize as needle-like samples exhibiting an axial texture with an identity period along texture of 5.3 A. A hexagonal elementary cell of EuA[sub 3] has the following parameters: a=18.6 A, c=10.4 A, z=2. As is evident from IR and luminescence (EuA[sub 3]) spectra, LnA[sub 3] molecules form rigid-chain coordination polymer structure with neighbouring coordination octahedra linked by alkylphosphate bridges. LnA[sub 3] is very poorly soluble in alkanes as well as in donor solvents. However, we developed the series systems in which the solubility of LnA[sub 3] increases dramatically as a result of the formation of oligomers or mixed-ligand complexes. Coordination chemical processes occurring in these systems have been studied using thermodynamic and spectroscopic methods. The structural formulae and strength of the complexes formed are discussed. On the decomposition of mixed-ligand complexes, considerable separation in the Am-lanthanides and Eu-lanthanides series occurs. ((orig.))

  13. Upper critical magnetic field of LnO{}_{0.5}F{}_{0.5}BiS2 (Ln = La, Nd) superconductors at ambient and high pressure

    Science.gov (United States)

    Fang, Y.; Wolowiec, C. T.; Breindel, A. J.; Yazici, D.; Ho, P.-C.; Maple, M. B.

    2017-11-01

    The upper critical fields H c2 of polycrystalline samples of LnO{}0.5F{}0.5BiS2 (Ln = La, Nd) at ambient pressure (tetragonal structure) and high pressure (HP) (monoclinic structure) have been investigated via electrical resistivity measurements at various magnetic fields up to 8.5 T. The H c2(T) curves for all the samples show an uncharacteristic concave upward curvature at temperatures below T c , which cannot be described by the conventional one-band Werthamer-Helfand-Hohenberg theory. For the LaO{}0.5F{}0.5BiS2 sample under HP, as temperature is decreased, the upper critical field H onset, estimated from the onset of the superconducting transitions, increases slowly between 4.9 and 5.8 T compared with the slope of H onset(T) below 4.9 T and above 5.8 T. This anomalous behavior reveals a remarkable similarity in superconductivity between LaO{}0.5F{}0.5BiS2 samples measured under HP and synthesized under HP, although the crystal structures of the two samples were reported to be different. A reasonable explanation is that local atomic environment, which can be tuned by applying external pressure, is essential to the enhancement of T c for BiS2-based superconductors. On the other hand, such anomalous behavior is very subtle in the case of NdO{}0.5F{}0.5BiS2 under HP, suggesting that the anisotropy of the upper critical field in the ab-plane and the possible lattice deformation induced by external pressure is weak. This explains why the pressure-induced enhancement of T c for NdO{}0.5F{}0.5BiS2 is not as large as that for LaO{}0.5F{}0.5BiS2.

  14. Hydrogenation Properties of Laves Phases LnMg2 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb).

    Science.gov (United States)

    Werwein, Anton; Maaß, Florian; Dorsch, Leonhard Y; Janka, Oliver; Pöttgen, Rainer; Hansen, Thomas C; Kimpton, Justin; Kohlmann, Holger

    2017-12-18

    The hydrogenation properties of Laves phases LnMg2 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb) were investigated by thermal analysis, X-ray, synchrotron, and neutron powder diffraction. At 14.0 MPa hydrogen gas pressure and 393 K, PrMg2 and NdMg2 take up hydrogen and form the colorless, ternary hydrides PrMg2H7 (P41212, a = 632.386(6) pm, c = 945.722(11) pm) and NdMg2H7 (P41212, a = 630.354(9) pm, c = 943.018(16) pm). The crystal structures were refined by the Rietveld method from neutron powder diffraction data on the deuterides (PrMg2D7, P41212, a = 630.56(2) pm, c = 943.27(3) pm; NdMg2D7, P41212, a = 628.15(2) pm, c = 940.32(3) pm) and shown to be isotypic to LaMg2D7. The LaMg2D7 type of hydrides decompose at 695 K (La), 684 K (Ce), 684 K (Pr), 672 K (Nd), and 639 K (Sm) to lanthanide hydrides and magnesium. The Laves phase EuMg2 forms a hydride EuMg2Hx of black color. Its crystal structure (P212121, a = 664.887(4) pm, b = 1136.993(7) pm, c = 1069.887(7) pm) is closely related to the hexagonal Laves phase (MgZn2 type) of the hydrogen-free parent intermetallic. GdMg2 and TbMg2 form hydrides GdMg2Hx with orthorhombic unit cells (a = 1282.7(4) pm, b = 572.5(2) pm, c = 881.7(2) pm) and TbMg2Hx (a = 617.8(3) pm, b = 1045.8(8) pm, c = 997.1(5) pm), presumably also with a distorted MgZn2 type of structure. CeMg2H7 and NdMg2H7 are paramagnetic with effective magnetic moments of 2.49(1) μB and 3.62(1) μB, respectively, in good agreement with the calculated magnetic moments of the free trivalent rare-earth cations (μcalc(Ce3+) = 2.54 μB; μcalc(Nd3+) = 3.62 μB).

  15. Thermochemistry of rare earth doped uranium oxides Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} (Ln = La, Y, Nd)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; Navrotsky, Alexandra, E-mail: anavrotsky@ucdavis.edu

    2015-10-15

    Lanthanum, yttrium, and neodymium doped uranium dioxide samples in the fluorite structure have been synthesized, characterized in terms of metal ratio and oxygen content, and their enthalpies of formation measured by high temperature oxide melt solution calorimetry. For oxides doped with 10–50 mol % rare earth (Ln) cations, the formation enthalpies from constituent oxides (LnO{sub 1.5}, UO{sub 2} and UO{sub 3} in a reaction not involving oxidation or reduction) become increasingly exothermic with increasing rare earth content, while showing no significant dependence on the varying uranium oxidation state. The oxidation enthalpy of Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} is similar to that of UO{sub 2} to UO{sub 3} for all three rare earth doped systems. Though this may suggest that the oxidized uranium in these systems is energetically similar to that in the hexavalent state, thermochemical data alone can not constrain whether the uranium is present as U{sup 5+}, U{sup 6+}, or a mixture of oxidation states. The formation enthalpies from elements calculated from the calorimetric data are generally consistent with those from free energy measurements. - Highlights: • We synthesize, characterize Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} solid solutions (Ln = La, Y, Nd). • Formation enthalpies become more exothermic with increasing rare earth content. • Oxidation enthalpy of Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} is similar to that of UO{sub 2} to UO{sub 3}. • Direct calorimetric measurements are in good agreement with free energy data.

  16. Highly-efficient multi-watt Yb:CaLnAlO4 microchip lasers

    Science.gov (United States)

    Loiko, Pavel; Serres, Josep Maria; Mateos, Xavier; Xu, Xiaodong; Xu, Jun; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc; Major, Arkady

    2017-02-01

    Tetragonal rare-earth calcium aluminates, CaLnAlO4 where Ln = Gd or Y (CALGO and CALYO, respectively), are attractive laser crystal hosts due to their locally disordered structure and high thermal conductivity. In the present work, we report on highly-efficient power-scalable microchip lasers based on 8 at.% Yb:CALGO and 3 at.% Yb:CALYO crystals grown by the Czochralski method. Pumped by an InGaAs laser diode at 978 nm, the 6 mm-long Yb:CALGO microchip laser generated 7.79 W at 1057-1065 nm with a slope efficiency of η = 84% (with respect to the absorbed pump power) and an optical-to-optical efficiency of ηopt = 49%. The 3 mm-long Yb:CALYO microchip laser generated 5.06 W at 1048-1056 nm corresponding to η = 91% and ηopt = 32%. Both lasers produced linearly polarized output (σ- polarization) with an almost circular beam profile and beam quality factors M2 x,y <1.1. The output performance of the developed lasers was modeled yielding a loss coefficient as low as 0.004-0.007 cm-1. The results indicate that the Yb3+- doped calcium aluminates are very promising candidates for high-peak-power passively Q-switched microchip lasers.

  17. Microchip Yb:CaLnAlO4 lasers with up to 91% slope efficiency.

    Science.gov (United States)

    Loiko, Pavel; Serres, Josep Maria; Mateos, Xavier; Xu, Xiaodong; Xu, Jun; Jambunathan, Venkatesan; Navratil, Petr; Lucianetti, Antonio; Mocek, Tomas; Zhang, Xuzhao; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc; Major, Arkady

    2017-07-01

    Multi-watt continuous-wave (CW) operation of tetragonal rare-earth calcium aluminate Yb:CaLnAlO4(Ln=Gd,Y)) crystals in plano-plano microchip lasers was demonstrated with an almost quantum-defect-limited slope efficiency. Pumped at 978 nm by an InGaAs laser diode, a 3.4 mm long 8 at. % Yb:CaGdAlO4 laser generated 7.79 W at 1057-1065 nm with a slope efficiency of η=84% (with respect to the absorbed pump power). An even higher η=91% was achieved with a 2.5 mm long 3 at. % Yb:CaYAlO4 laser, from which 5.06 W were extracted at 1048-1056 nm. Both lasers produced linearly polarized output (σ-polarization) with an almost circular diffraction-limited beam (Mx,y2<1.1). The output performance of the developed lasers was modeled, yielding an internal loss coefficient as low as 0.004-0.007  cm-1. In addition, their spectroscopic properties were revisited.

  18. On the constitutive model of nitrogen-containing austenitic stainless steel 316LN at elevated temperature.

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    Full Text Available The nitrogen-containing austenitic stainless steel 316LN has been chosen as the material for nuclear main-pipe, which is one of the key parts in 3rd generation nuclear power plants. In this research, a constitutive model of nitrogen-containing austenitic stainless steel is developed. The true stress-true strain curves obtained from isothermal hot compression tests over a wide range of temperatures (900-1250°C and strain rates (10(-3-10 s(-1, were employed to study the dynamic deformational behavior of and recrystallization in 316LN steels. The constitutive model is developed through multiple linear regressions performed on the experimental data and based on an Arrhenius-type equation and Zener-Hollomon theory. The influence of strain was incorporated in the developed constitutive equation by considering the effect of strain on the various material constants. The reliability and accuracy of the model is verified through the comparison of predicted flow stress curves and experimental curves. Possible reasons for deviation are also discussed based on the characteristics of modeling process.

  19. Lanthanide complexes of macrocyclic polyoxovanadates by VO4 units: synthesis, characterization, and structure elucidation by X-ray crystallography and EXAFS spectroscopy.

    Science.gov (United States)

    Nishio, Masaki; Inami, Shinnosuke; Katayama, Misaki; Ozutsumi, Kazuhiko; Hayashi, Yoshihito

    2012-01-16

    Reactions of a tetravanadate anion, [V(4)O(12)](4-), with a series of lanthanide(III) salts yield three types of lanthanide complexes of macrocyclic polyoxovanadates: (Et(4)N)(6)[Ln(III)V(9)O(27)] [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6)], (Et(4)N)(5)[(H(2)O)Ho(III)(V(4)O(12))(2)] (7), and (Et(4)N)(7)[Ln(III)V(10)O(30)] [Ln = Er (8), Tm (9), Yb (10), Lu (11)]. Lanthanide complexes 1-11 are isolated and characterized by IR, elemental analysis, single-crystal X-ray diffraction, and extended X-ray absorption fine structure spectroscopy (EXAFS). Lanthanide complexes 1-6 are composed of a square-antiprism eight-coordinated Ln(III) center with a macrocyclic polyoxovanadate that is constructed from nine VO(4) tetrahedra through vertex sharing. The structure of 7 is composed of a seven-coordinated Ho(III) center, which exhibits a capped trigonal-prism coordination environment by the sandwiching of two cyclic tetravanadates with a capping H(2)O ligand. Lanthanide complexes 8-11 have a six-coordinated Ln(III) center with a 10-membered vanadate ligand. The structural trend to adopt a larger coordination number for a larger lanthanide ion among the three types of structures is accompanied by a change in the vanadate ring sizes. These lanthanide complexes are examined by EXAFS spectroscopies on lanthanide L(III) absorption edges, and the EXAFS oscillations of each of the samples in the solid state and in acetonitrile are identical. The Ln-O and Ln···V bond lengths obtained from fits of the EXAFS data are consistent with the data from the single-crystal X-ray studies, reflecting retention of the structures in acetonitrile.

  20. Intracluster interactions in butterfly {Fe3LnO2} molecules with the non-Kramers ions Tb(III) and Ho(III)

    Science.gov (United States)

    Badía-Romano, L.; Rubín, J.; Bartolomé, F.; Bartolomé, J.; Luzón, J.; Prodius, D.; Turta, C.; Mereacre, V.; Wilhelm, F.; Rogalev, A.

    2015-08-01

    The intracluster exchange interactions within the "butterfly" [Fe3Ln (μ3-O )2(CCl3COO )8(H2O )(THF )3] molecules, where Ln(III) represents a lanthanide cation, have been determined by a combination of x-ray magnetic circular dichroism (XMCD) and vibrating sample magnetometry (VSM) along with an interaction model. We have studied the compounds with Ln =Tb and Ho, both non-Kramers lanthanides and with high uniaxial anisotropy, and Ln =Lu (III) and Y(III) as pseudolanthanides, which supply nonmagnetic Ln reference cases. At low temperature, the three Fe atoms can be considered as a self-unit with total spin SFe 3=5 /2 . Using the element selectivity of the XMCD magnetometry, measured at the Ln L2 ,3 edges, together with the VSM measurements, the local magnetization of the Ln ion and the Fe3 subcluster, as a function of the field and low temperature (T ≈2.5 K ), has been determined separately. These results are described quantitatively in the framework of a theoretical model based on an effective spin Hamiltonian, which considers the competing effects of intracluster interactions and the external applied magnetic field. The Ln -Fe3 exchange interaction within the {Fe3LnO2} cluster has been determined to be antiferromagnetic, in both Tb and Ho compounds, with JFeTb/kB=-0.13 (1 ) K and JFeHo/kB=-0.18 (1 ) K , respectively. In both cases, a field-induced reorientation of the Fe3 and Ln spins from antiparallel to parallel orientation takes place at a threshold field μ0H =1.1 and 2 T, for the {Fe3TbO2} and {Fe3HoO2} compounds, respectively. By comparison with other compounds of the series with uniaxial anisotropy, it is concluded that the polarizability of the Fe3 subcluster magnetic moment decreases in the trend {Fe3YO2}→{Fe3TbO2}→{Fe3HoO2}→{Fe3DyO2} , because of the increasing opposition of the exchange antiferromagnetic field caused by the Ln ion. In the Ln =Tb , Ho, and Dy, the magnetization of the whole molecule is dominated by the anisotropy of the Ln ion

  1. Laser Raman microscopic studies of passive films formed on type 316LN stainless steels during pitting in chloride solution

    Energy Technology Data Exchange (ETDEWEB)

    Ramya, S.; Anita, T. [Corrosion Science and Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Shaikh, H. [Corrosion Science and Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)], E-mail: hasan@igcar.gov.in; Dayal, R.K. [Corrosion Science and Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)

    2010-06-15

    The surface films formed on type 316LN stainless steels (SS) with different nitrogen contents, during potentiodynamic polarization in acidified 1 M NaCl solution, were characterized by Laser Raman Spectroscopy (LRS). LRS confirmed the presence of oxides and oxychlorides of iron and chromium, hydrated chlorides and nitrates in the film. Raman mapping showed increasing nitrate content in the film with increasing nitrogen content. The film on the uncorroded material showed the presence of chromium and molybdenum oxides. The improvement in pitting corrosion resistance of type 316LN SS with increasing nitrogen content was attributed to increased amount of nitrates in the passive film.

  2. Site-selective fluorescence spectroscopy investigations of LnPO{sub 4} xenotime ceramics for radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, A.; Peters, L. [RWTH Aachen Univ. (Germany). Inst. of Crystallography; Holthausen, J.; Neumeier, S. [Forschungszentrum Juelich (Germany); Huittinen, Nina [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Loesch, Henry

    2017-06-01

    Europium incorporation in different LnPO{sub 4} (Ln=Tb, Lu and Gd{sub 1-x}Lu{sub x}) phases crystallizing in the xenotime structure was investigated with site-selective TRLFS, PXRD and Rietveld analyses. Based on recorded emission spectra and diffraction patterns, the formation of three different crystal systems (xenotime, anhydrite, and monazite) could be identified. Aging of the ceramic samples and a second sintering step led to an accumulation of europium in the grain boundaries and on the surface.

  3. In situ hydrothermal syntheses, structures and photoluminescent properties of four novel metal-organic frameworks constructed by lanthanide (Ln=Ce(III), Pr(III), Eu(III)) and Cu(I) metals with flexible dicarboxylate acids and piperazine-based ligands

    Energy Technology Data Exchange (ETDEWEB)

    Ay, Burak; Karaca, Serkan [Department of Chemistry, Arts and Science Faculty, Çukurova University, 01330 Adana (Turkey); Yildiz, Emel, E-mail: eeyildiz@cu.edu.tr [Department of Chemistry, Arts and Science Faculty, Çukurova University, 01330 Adana (Turkey); Lopez, Valerie [Department of Chemistry, Syracuse University, Syracuse, NY 13244 (United States); Nanao, Max H. [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9 (France); University Grenoble Alpes-Centre National de la Recherche Scientifique-EMBL Unit of Virus Host-Cell Interactions, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9 (France); Zubieta, Jon [Department of Chemistry, Syracuse University, Syracuse, NY 13244 (United States); Université Grenoble Alpes Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)

    2016-01-15

    Four novel metal-organic frameworks,[Cu{sub 2}Cl{sub 2}(pyrz)]{sub n} (1) and (H{sub 2}pip){sub n}[Ln{sub 2}(pydc){sub 4}(H{sub 2}O){sub 2}]{sub n} (Ln=Ce (2), Pr (3) and Eu (4), H{sub 2}pzdc=2,3-pyrazinedicarboxylic acid, pyrz=pyrazine, H{sub 2}pydc=2,6-pyridinedicarboxylic acid, H{sub 2}pip=piperazine) have been synthesized under hydrothermal conditions and characterized by the elemental analysis, ICP, Far IR (FIR), FT-IR spectra, TGA, single crystal X-ray diffraction analysis and powder X-ray diffraction (PXRD). Compound 1 is two-dimensional containing Cl-Cu-Cl sites, while the lanthanide complexes contain one-dimensional infinite Ln–O-Ln chains. All the complexes show high thermal stability. The complexes 1–3 exhibit luminescence emission bands at 584, 598 and 614 nm at room temperature when excited at 300 nm. Complex 4 exhibits bright red solid-state phosphorescence upon exposure to UV radiation at room temperature. - Graphical abstract: Four novel metal-organic frameworks have been synthesized under hydrothermal conditions. Thermal and luminescent properties of the compounds have been investigated.

  4. Synthesis, structures, and luminescent properties of lanthanide complexes with triphenylphospine oxide

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yan; Xu, Shan; Wang, Xin; Li, Yue-Xue; Jin, Qiong-Hua [Department of Chemistry, Capital Normal University, Beijing (China); Liu, Min [The College of Materials Science and Engineering, Beijing University of Technology (China); Xin, Xiu-Lan [School of Food and Chemical Engineering, Beijing Technology and Business University (China)

    2017-07-03

    Seven lanthanide complexes [Ln(OPPh{sub 3}){sub 3}(NO{sub 3}){sub 3}] (1-3) (OPPh{sub 3} = triphenylphosphine oxide, Ln = Nd, Sm, Gd), [Dy(OPPh{sub 3}){sub 4}(NO{sub 3}){sub 2}](NO{sub 3}) (4), [Ln(OPPh{sub 3}){sub 3}(NO{sub 3}){sub 3}]{sub 2} (5-7) (Ln = Pr, Eu, Gd) were synthesized by the reactions of different lanthanide salts and OPPh{sub 3} ligand in the air. These complexes were characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR and fluorescence spectra. Structure analysis shows that complexes 1-4 are mononuclear complexes formed by OPPh{sub 3} ligands and nitrates. The asymmetric units of complexes 5-7 consist of two crystallographic-separate molecules. Complex 1 is self-assembled to construct a 2D layer-structure of (4,4) net topology by hydrogen bond interactions. The other complexes show a 1D chain-like structure that was assembled by OPPh{sub 3} ligands and nitrate ions through C-H..O interactions. Solid emission spectra of compounds 4 and 6 are assigned to the characteristic fluorescence of Tb{sup 3+} (λ{sub em} = 480, 574 nm) and Eu{sup 3+} (λ{sub em} = 552, 593, 619, 668 nm). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. 1H-NMR studies on the ternary complexes of rare-earth ions with thenoyltrifluoroacetone and polyethers in dichloromethane.

    Science.gov (United States)

    Gagabe, Gene Frederick; Satoh, Keiichi; Sawada, Kiyoshi

    2009-07-28

    The structures of the ternary complexes of lanthanoid and yttrium (Ln3+)-thenoyltrifluoroacetonates (tta-) with polyether (POE) in organic phase were investigated by 1H-NMR spectroscopy, where the POEs are crown ethers (18-crown-6 and benzo-18-crown-6) and monodispersed linear polyethers (DEOn: HO-(CH2CH2O-)nC12H25, where n=4, 6, 8). The changes in chemical shift of methylene protons of POE by addition of the adduct complex [Ln(tta)3(POE)] were measured at various Ln3+-to-POE concentration ratios. Chemical shift changes for each proton of POE by the formation of [Ln(tta)3(POE)] were determined. Results revealed that oxygen atoms at the hydroxyl terminal of linear POE have higher tendency to coordinate to the metal ion in [Ln(tta)3] complex. Three (for La3+) or two (for Lu3+ or Y3+) oxygen atoms of the POE coordinate to the metal ion without substitution of tta- ligands to satisfy the metal ion's coordination number of nine or eight, respectively. In the case of 18-membered crown ether complexes, La3+ is incorporated inside the cavity of the POE, displacing one of the three tta- from the inner coordination sphere while the other two remain coordinated to the metal ion. On the other hand, for the adduct of Y3+ complex with crown ether, all three tta- ligands are directly coordinating to the metal ion.

  6. Synthesis, structure and luminescence property of 2D lanthanide complexes with 3-fluorophthalate and oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Yu-E [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Li, Xia, E-mail: xiali@mail.cnu.edu.cn [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Song, Shuang [Department of Chemistry, Capital Normal University, Beijing 100048 (China)

    2012-12-15

    Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (Ln=Sm 1, Eu 2, Tb 3 and Dy 4; fpht=3-fluorophthalate and ox=oxalate) have been synthesized and structurally characterized by single crystal X-ray diffraction. The four complexes possess similar 2D framework structures constructed from Ln-fpht double-stranded helices and ox linkages. Complexes 2 and 3 display the characteristic emission {sup 5}D{sub 0}{yields}{sup 7}F{sub J} (J=0-4) transitions of Eu(III) ion and {sup 5}D{sub 4}{yields}{sup 7}F{sub J} (J=6-3) transitions of Tb(III) ion, respectively. The emission decay curves reveal a monoexponential behavior yielding the lifetime values of 0.266{+-}0.002 ms for 2 and 0.733{+-}0.002 ms for 3. The emission spectrum of 1 shows three weak bands corresponding to the characteristic emission {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 5/2}, {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} and {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 9/2} transitions of Sm(III) ion. The emission spectrum of 4 displays a broad band centered at 438 nm, which comes from the {pi}{sup Low-Asterisk }-{pi} transition of the ligand. - Graphical abstract: Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate, ox=oxalate) possess 2D structures. Sm(III), Eu(III) and Tb(III) complexes show the characteristic fluorescent emission of the Ln(III). Dy(III) complex displays ligand-based luminescent behavior. Highlights: Black-Right-Pointing-Pointer [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate; ox=oxalate) show 2D structures. Black-Right-Pointing-Pointer The 2D structures are constructed from Ln-fpht double-stranded helices and ox linkage. Black-Right-Pointing-Pointer The Sm(III), Eu(III) and Tb(III) complexes show the characteristic emission of the Ln(III) ions. Black-Right-Pointing-Pointer Dy(III) complex displays ligand-based luminescent behavior.

  7. Cyanomethylene-bis(phosphonate)-based lanthanide complexes: structural, photophysical, and magnetic investigations.

    Science.gov (United States)

    Maxim, Catalin; Branzea, Diana G; Tiseanu, Carmen; Rouzières, Mathieu; Clérac, Rodolphe; Andruh, Marius; Avarvari, Narcis

    2014-03-03

    The syntheses, structural investigations, magnetic and photophysical properties of a series of 10 lanthanide mononuclear complexes, containing the heteroditopic ligand cyanomethylene-bis(5,5-dimethyl-2-oxo-1,3,2λ(5)-dioxa-phosphorinane) (L), are described. The crystallographic analyses indicate two structural types: in the first one, [Ln(III)(L)3(H2O)2]·H2O (Ln = La, Pr, Nd), the metal ions are eight-coordinated within a square antiprism geometry, while the second one, [Ln(III)(L)3(H2O)]·8H2O (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er), contains seven-coordinated Ln(III) ions within distorted monocapped trigonal prisms. Intermolecular hydrogen bonding between nitrogen atoms of the cyano groups, crystallization, and coordination water molecules leads to the formation of extended supramolecular networks. Solid-state photophysical investigations demonstrate that Eu(III) and Tb(III) complexes possess intense luminescence with relatively long excited-state lifetimes of 530 and 1370 μs, respectively, while Pr(III), Dy(III), and Ho(III) complexes have weak intensity luminescence characterized by short lifetimes ranging between a few nanoseconds to microseconds. The magnetic properties for Pr(III), Gd(III), Tb(III), Dy(III), and Ho(III) complexes are in agreement with isolated Ln(III) ions in the solid state, as suggested by the single-crystal X-ray analyses. Alternating current (ac) susceptibility measurements up to 10 kHz reveal that only the Ho(III) complex shows a frequency-dependent ac response, with a relaxation mode clearly observed at 1.85 K around 4500 Hz.

  8. Solid state reaction synthesis and optical spectroscopy of ferroelectric (Gd{sub 1-x}Ln{sub x}){sub 2}(MoO{sub 4}){sub 3}; with Ln = Yb or Tm

    Energy Technology Data Exchange (ETDEWEB)

    Lin Zhoubin; Han Xiumei [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain); Zaldo, Carlos, E-mail: cezaldo@icmm.csic.e [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain)

    2010-03-04

    A solid state synthesis route was used to prepare (Gd{sub 1-x}Ln{sub x}){sub 2}(MoO{sub 4}){sub 3}, Ln = Yb or Tm, compounds with ferroelectric Pba2 crystal structure. It has been observed that this phase is the only one crystallized during 1123 K annealing for x {<=} 0.12 for Yb and x {<=} 0.3 for Tm. Above these concentration limits the simultaneous formation of trihydrated Ln{sub 2}(MoO{sub 4}){sub 3}, Ln = Yb or Tm, is observed. Up to these concentrations Yb and Tm incorporations do not degrade the SHG efficiency. The position of Yb{sup 3+} and Tm{sup 3+} energy levels involved in laser emission processes were determined by 5 K spectroscopy. The 300 K pumping and emission spectral distributions and excited level lifetime have been determined with the purpose of future applications as self-activated periodically poled ferroelectric laser and non-linear media.

  9. Defect Scheelite-Type Lanthanoid(III Ortho-Oxomolybdates(VI Ln0.667[MoO4] (Ln = Ce, Pr, Nd, and Sm and Their Relationship to Zircon and the NaTl-Type Structure

    Directory of Open Access Journals (Sweden)

    Ingo Hartenbach

    2011-12-01

    Full Text Available The rare-earth metal(III ortho-oxomolybdates with the formula Ln0.667[MoO4] (Ln = Ce, Pr, Nd, and Sm and defect scheelite-type structure crystallize in the tetragonal space group I41/a (a = 533–525, c = 1183–1158 pm with four formula units per unit cell. The Ln3+ cations at Wyckoff position 4b exhibit a coordination sphere of eight oxygen atoms in the shape of a trigonal dodecahedron. The same site symmetry (.. is observed for the tetrahedral oxomolybdate(VI entities [MoO4]2–, since their central Mo6+ cation is situated at the 4a position. Due to this equal site multiplicity, the lanthanoid(III cations have to be statistically under-occupied to maintain electroneutrality, thus a defect scheelite structure emerges. The partial structure of both the Ln3+ cations and the [MoO4]2– anions (if shrunk to their centers of gravity can be best described as distorted diamond-like arrangements. Therefore, these two interpenetrating partial structures exhibit a similar setup as found in the zircon-type as well as in the NaTl-type structure.

  10. Návrh GUI multimediálního centra pro seniory

    OpenAIRE

    Gongol, Jakub

    2015-01-01

    Práce se zabývá problematikou tvorby grafického uživatelského rozhraní pro seniory se zaměřením na dotyková zařízení. Cílem je návrh a vytvoření aplikace ovladače multimediálního centra XBMC pro platformu Android. Práce také popisuje některá existující řešení a testování vytvořené aplikace. This thesis covers the subject a graphical user interface for the erderly with focus on smartphones and tablets. The main object is design and creation of an Android application for remote control of th...

  11. Metabolites from an endophytic fungus sphaceloma sp. LN-15 isolated from the leaves of Melia azedarach.

    Science.gov (United States)

    Zhang, An-Ling; He, Li-Ying; Gao, Jin-Ming; Xu, Xu; Li, Shi-Qing; Bai, Ming-Sheng; Qin, Jian-Chun

    2009-08-01

    Two new natural compounds, a symmetrical disulfide dimer didodecyl 3,3''-dithiodipropionate (1) and a pregnane steroid 5,16-pregnadien-3beta-ol-20-one acetate (2), were isolated together with two known compounds, ergosta-4,6,8(14),22-tetraen-3-one (3) and ergosterol peroxide (4), from the ethyl acetate soluble extract of fermentation broth of an endophytic fungus, Sphaceloma sp. LN-15 isolated from the leaves of Melia azedarach L. and grown in pure culture. Their structures were determined on the basis of spectroscopic methods including 1D and 2D nuclear magnetic resonance spectroscopy (NMR) experiments and by mass spectrometric measurements (MS). These fungal metabolites were isolated for the first time from the genus Sphaceloma. The structure of 1 was also confirmed by chemical synthesis.

  12. Corrosion fatigue behaviour of 317LN austenitic stainless steel in phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Onoro, J. [Ingenieria y Ciencia de los Materiales, ETSI Industriales, Universidad Politecnica de Madrid, c/Jose Gutierrez Abascal, 2, 28006 Madrid (Spain)], E-mail: javier.onoro@upm.es

    2009-10-15

    The corrosion fatigue crack-growth behaviour of AISI 317LN stainless steel was evaluated in air and in 85% phosphoric acid at 20 deg. C. Austenitic stainless steels with high molybdenum content have high corrosion resistance and good mechanical properties. However, this increase in the molybdenum content and other elements such as nitrogen can also modify the microstructure. This leads to a modification of its mechanical properties. The corrosion fatigue crack-growth rate was higher in phosphoric acid immersion than in air. Austenitic stainless steels with a fully austenitic microstructure were more ductile, tough, and behave better against corrosion fatigue. The higher resistance to corrosion fatigue was directly associated to its higher resistance to corrosion.

  13. Influence of Heat Treatment on Mercury Cavitation Resistance of Surface Hardened 316LN Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J [ORNL; Hsu, Julia [Massachusetts Institute of Technology (MIT)

    2010-11-01

    The cavitation-erosion resistance of carburized 316LN stainless steel was significantly degraded but not destroyed by heat treatment in the temperature range 500-800 C. The heat treatments caused rejection of some carbon from the carburized layer into an amorphous film that formed on each specimen surface. Further, the heat treatments encouraged carbide precipitation and reduced hardness within the carburized layer, but the overall change did not reduce surface hardness fully to the level of untreated material. Heat treatments as short as 10 min at 650 C substantially reduced cavitation-erosion resistance in mercury, while heat treatments at 500 and 800 C were found to be somewhat less detrimental. Overall, the results suggest that modest thermal excursions perhaps the result of a weld made at some distance to the carburized material or a brief stress relief treatment will not render the hardened layer completely ineffective but should be avoided to the greatest extent possible.

  14. Study of ln s Physics in $\\bar{p}p$ Interactions at the Split Field Magnet

    CERN Multimedia

    2002-01-01

    This experiment uses the Split Field Magnet detector to investigate the low p^t, ``ln~s'', type of interactions that dominate the @*p cross-section. Systematic comparisons will be made to pp interactions. \\\\ \\\\ Specific areas to be studied include elastic scattering in the regions 0.05 $<$ !t! $<$ 0.8 GeV|2 and 0.8 $<$ !t! $<$ 4.0 GeV|2, and the use of a minimum bias trigger to study topological cross-sections, inclusive spectra, and two-body correlations. Some specialized triggers, run simultaneously with the high t elastic scattering trigger, are being studied. Examples are a trigger requiring Cerenkov identification in a limited region of phase space, and a trigger to select diffractively produced events.

  15. Controlled processing of (Gd,Ln2O3:Eu (Ln = Y, Lu red phosphor particles and compositional effects on photoluminescence

    Directory of Open Access Journals (Sweden)

    Bin Lu

    2013-11-01

    Full Text Available Synthesis of (Gd0.95−xLnxEu0.052O3 (Ln = Y and Lu, x = 0–0.95 powders via ammonium hydrogen carbonate (AHC precipitation has been systematically studied. The best synthesis parameters are found to be an AHC/total cation molar ratio of 4.5 and an ageing time of 3 h. The effects of Y3+ and Lu3+ substitution for Gd3+, on the nucleation kinetics of the precursors and structural features and optical properties of the oxides, have been investigated. The results show that (i different nucleation kinetics exist in the Gd–Y–Eu and Gd–Lu–Eu ternary systems, which lead to various morphologies and particle sizes of the precipitated precursors. The (Gd,Y2O3:Eu precursors display spherical particle morphologies and the particle sizes increase along with more Y3+ addition. The (Gd,Lu2O3:Eu precursors, on the other hand, are hollow spheres and the particle sizes increase with increasing Lu3+ incorporation, (ii the resultant oxide powders are ultrafine, narrow in size distribution, well dispersed and rounded in particle shape, (iii lattice parameters of the two kinds of oxide solid solutions linearly decrease at a higher Y3+ or Lu3+ content. Their theoretical densities linearly decrease with increasing Y3+ incorporation, but increase along with more Lu3+ addition and (iv the two kinds of phosphors exhibit typical red emissions at ~613 nm and their charge-transfer bands blue shift at a higher Y3+ or Lu3+ content. Photoluminescence/photoluminescence excitation intensities and external quantum efficiency are found to decrease with increasing value of x, and the fluorescence lifetime mainly depends on the specific surface areas of the powders.

  16. Magnetic interactions in new fluorite-related rare earth oxides LnLn’{sub 2}RuO{sub 7} (Ln, Ln’=rare earths)

    Energy Technology Data Exchange (ETDEWEB)

    Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp; Doi, Yoshihiro

    2016-07-15

    New fluorite-related quaternary rare earth oxides Pr{sub 2}YRuO{sub 7} and La{sub 2}TbRuO{sub 7} have been prepared. They crystallize in an orthorhombic superstructure of cubic fluorite with space group Cmcm. Through magnetic susceptibility and specific heat measurements, Pr{sub 2}YRuO{sub 7} shows an antiferromagnetic transition at 27 K, which is considerably lowered compared with that for Pr{sub 3}RuO{sub 7}. Analysis of the magnetic specific heat indicates that the magnetic behavior observed at 27 K for Pr{sub 2}YRuO{sub 7} is predominantly due to the magnetic interactions between Ru ions, and that the interactions between the Pr{sup 3+} and Ru{sup 5+} ions are also important. La{sub 2}TbRuO{sub 7} shows magnetic ordering at 9.0 K, which is ascribed to the magnetic ordering between Ru{sup 5+} ions from the analysis of the magnetic specific heat data. - Graphical abstract: New fluorite-related quaternary rare earth oxides Pr{sub 2}YRuO{sub 7} and La{sub 2}TbRuO{sub 7} have been prepared. Through magnetic susceptibility and specific heat measurements, Pr{sub 2}YRuO{sub 7} and La{sub 2}TbRuO{sub 7} show an antiferromagnetic transition at 27 and 9.0 K, respectively. Display Omitted - Highlights: • New fluorite-related quaternary rare earth oxides LnLn’{sub 2}RuO{sub 7} have been prepared. • Pr{sub 2}YRuO{sub 7} shows an antiferromagnetic transition at 27 K. • La{sub 2}TbRuO{sub 7} shows magnetic ordering at 9.0 K. • Their magnetic exchange mechanism has been elucidated by the magnetic entropy change.

  17. Design Guidelines for Collaboration and Participation with Examples from the LN4LD (Learning Network for Learning Design)

    NARCIS (Netherlands)

    Burgos, Daniel; Hummel, Hans; Tattersall, Colin; Brouns, Francis; Koper, Rob

    2007-01-01

    Burgos, D., Hummel, H. G. K., Tattersall, C., Brouns, F., & Koper, R. (2009). Design Guidelines for Collaboration and Participation with Examples from the LN4LD (Learning Network for Learning Design). In L. Lockyer, S. Bennett, S. Agostinho & B. Harper (Eds.), Handbook of Research on Learning Design

  18. Reaction of (CP(2)asterisk-lnH)(2) (ln=Y, La) and CP(2)asterisk-Y(2-C(6)H(4)CH(2)NMe(2)) with esters and amides and molecular-structure of [CP(2)asterisk-Y(mu- ocme=chc(oet)o)](2)

    NARCIS (Netherlands)

    Deelman, B.J; Wierda, F.; Meetsma, A.; Teuben, J.H

    1995-01-01

    The activation of esters and amides by (Cp(2)*LnH)(2) [Ln = Y (1a), Ln = La (1b), Cp*=C(5)Me] and Cp(2)*Y(2-C(6)H(4)CH(2)NMe(2)) (2) is described. Compounds 1a and 1b react with ethyl acetate to form Cp(2)*YOEt (3a) and Cp(2)*LaOEt (30). With 1a and ethyl benzoate a 1:1 mixture of 3a and

  19. Preparation of photoluminescent PMMA doped with tris(pyrazol-1-yl)borate lanthanide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bortoluzzi, Marco, E-mail: markos@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Paolucci, Gino, E-mail: paolucci@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Gatto, Mattia; Roppa, Stefania [Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Enrichi, Francesco [CIVEN, Coordinamento Interuniversitario Veneto per le Nanotecnologie, Via delle Industrie 5, 30175 Marghera (Venezia) (Italy); Ciorba, Serena; Richards, Bryce S. [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS (United Kingdom)

    2012-09-15

    The neutral homoleptic Ln(III) complex Ln(Tp){sub 3} (Ln=Sm, Eu, Tb, Yb; Tp=hydrotris(pyrazol-1-yl)borate) were used as dopants for the preparation of novel photoluminescent poly(methyl methacrylate) glasses indicated as Ln(Tp){sub 3}-PMMA. The doped polymers containing samarium, europium and terbium derivatives showed emission associated to f-f transitions in the visible range upon excitation with UV light, while a NIR emission was obtained from Yb(Tp){sub 3}-PMMA. The maximum incident wavelength able to induce emissions from the Ln(Tp){sub 3}-doped polymers depends upon the choice of the lanthanide ion. No meaningful antenna-effect was instead observed using dysprosium as metal centre. - Highlights: Black-Right-Pointing-Pointer Polymers doped with photoluminescent lanthanide complexes. Black-Right-Pointing-Pointer Hydrotris(pyrazol-1-yl)borate (Tp) as antenna-ligand for Sm(III), Eu(III), Tb(III) and Yb(III). Black-Right-Pointing-Pointer Emission associated to f-f transitions upon excitation with UV light. Black-Right-Pointing-Pointer No antenna-effect for dysprosium derivative. Black-Right-Pointing-Pointer Photoluminescence excitation spectra are dependent upon the lanthanide ion.

  20. Controlling dimensionality via a dual ligand strategy in Ln-thiophene-2,5-dicarboxylic acid-terpyridine coordination polymers.

    Science.gov (United States)

    Carter, Korey P; Zulato, Cecília H F; Rodrigues, Emille M; Pope, Simon J A; Sigoli, Fernando A; Cahill, Christopher L

    2015-09-28

    Eleven new lanthanide (Ln = Nd-Lu)-thiophene-2,5-dicarboxylic acid (25-TDC)-2,2':6',2''-terpyridine (terpy) coordination polymers () which employ a dual ligand strategy have been synthesized hydrothermally and structurally characterized by single crystal and powder X-ray diffraction. Two additional members of the series ( and ) were made with Ce(3+) and Pr(3+) and characterized via powder X-ray diffraction only. The series is comprised of three similar structures wherein differences due to the lanthanide contraction manifest in Ln(3+) coordination number as well as the number of bound and solvent water molecules within the crystal lattice. Structure type I (Ce(3+)-Sm(3+)) contains two nine-coordinate Ln(3+) metal centers each with a bound water molecule. Structure type II (Eu(3+)-Ho(3+)) features a nine and an eight coordinate Ln(3+) metal along with one bound and one solvent water molecule. Structure type III (Er(3+)-Lu(3+)) includes two eight-coordinate Ln(3+) metal centers with both water molecules residing in the lattice. Assembly into supramolecular 3D networks via π-π interactions is observed for all three structure types, whereas structure types II and III also feature hydrogen-bonding interactions via the well-known C-HO and O-HO synthons. Visible and near-IR luminescence studies were performed on compounds , , , and at room temperature. As a result characteristic near-IR luminescent bands of Pr(3+), Nd(3+), Sm(3+), and Yb(3+) as well as visible bands of Sm(3+) were observed.

  1. Iron lanthanide phosphonate clusters: {Fe6Ln6P6} Wells-Dawson-like structures with D3d symmetry.

    Science.gov (United States)

    Pineda, Eufemio Moreno; Tuna, Floriana; Zheng, Yan-Zhen; Teat, Simon J; Winpenny, Richard E P; Schnack, Jürgen; McInnes, Eric J L

    2014-03-17

    Reaction of [Fe3(μ3-O)(O2C(t)Bu)6(HO2C(t)Bu)3](O2C(t)Bu) and [Ln2(O2C(t)Bu)6(HO2C(t)Bu)6] (Ln = lanthanide) with three different phosphonic acids produce a family of highly symmetrical {Fe6Ln6P6} clusters with general formula [Fe6Ln6(μ3-O)2(CO3)(O3PR)6(O2C(t)Bu)18], where R = methyl 1, phenyl 2, or n-hexyl 3. All the clusters present an analogous metal frame to the previously reported {Ni6Ln6P6} both being related to the well-known Wells-Dawson ion from polyoxometallate chemistry. These highly symmetrical clusters have, or approximate very closely to, D3d point symmetry. Both Fe(III) and Gd(III) ions are magnetically isotropic and could thus exhibit promising magnetocaloric properties; hence we investigated the {Fe6Gd6P6} compounds accordingly. Modeling the magnetic data of [Fe6Gd6(μ3-O)2(CO3)(O3PPh)6(O2C(t)Bu)18] by the finite-temperature Lanczos method gave a strong antiferromagnetic Fe···Fe interaction (J(Fe-Fe) = -30 cm(-1)) and very weak Gd···Gd and Gd···Fe exchange interactions (|J| < 0.1 cm(-1)). The strong antiferromagnetic Fe···Fe interaction could account for the relatively smaller -ΔSm value observed, compared against the {Ni6Gd6P6} analogues.

  2. Complexation of Actinide(III) and Lanthanide(III) with H4TPAEN for a Separation of Americium from Curium and Lanthanides.

    Science.gov (United States)

    Boubals, Nathalie; Wagner, Christoph; Dumas, Thomas; Chanèac, Léa; Manie, Gabriel; Kaufholz, Peter; Marie, Cécile; Panak, Petra J; Modolo, Giuseppe; Geist, Andreas; Guilbaud, Philippe

    2017-07-17

    Previous studies have identified the TPAEN ligand as a potentially appropriate complexing agent in solvent extraction processes for the separation of americium (Am(III)) from the fission products including lanthanide (Ln(III)) and curium (Cm(III)) ions, a challenging issue for advanced nuclear fuel recycling. To get insight into the selectivity of this ligand, the complexation of selected trivalent Ln(III) and actinide (An(III)) cations with TPAEN was investigated in solution. First, the structure and stoichiometry of the TPAEN complex with Am(III) were characterized by extended X-ray absorption fine structure spectroscopy (EXAFS). Then complexation constants and thermodynamics data were acquired for the complexes using different methods: microcalorimetry for the Ln(III) cations, time-resolved laser fluorescence spectroscopy (TRLFS) for Eu(III) and Cm(III), and UV-visible spectroscopy for Nd(III) and Am(III).

  3. Sulfate Exchange of the Nitrate-Type Layered Hydroxide Nanosheets of Ln2(OH)5NO3· nH2O for Better Dispersed and Multi-color Luminescent Ln2O3 Nanophosphors (Ln = Y0.98RE0.02, RE = Pr, Sm, Eu, Tb, Dy, Ho, Er, and Tm)

    Science.gov (United States)

    Wu, Xiaoli; Liu, Weigang; Li, Ji-Guang; Zhu, Qi; Li, Xiaodong; Sun, Xudong

    2016-07-01

    Through restricting thickness growth by performing coprecipitation at the freezing temperature of ~4 °C, solid-solution nanosheets (up to 5-nm thick) of the Ln2(OH)5NO3· nH2O layered hydroxide (Ln = Y0.98RE0.02; RE = Pr, Sm, Eu, Tb, Dy, Ho, Er, and Tm, respectively) were directly synthesized without performing conventional exfoliation. In situ exchange of the interlayer NO3 - with SO4 2- produced a sulfate derivative [Ln2(OH)5(SO4)0.5· nH2O] of the same layered structure and two-dimensional crystallite morphology but substantially contracted d 002 basal spacing (from ~0.886 to 0.841 nm). The sulfate derivative was systematically compared against its nitrate parent in terms of crystal structure and phase/morphology evolution upon heating. It is shown that the interlayer SO4 2-, owing to its bonding with the hydroxide main layer, significantly raises the decomposition temperature from ~600 to 1000 °C to yield remarkably better dispersed oxide nanopowders via a monoclinic Ln2O2SO4 intermediate. The resultant (Y0.98RE0.02)2O3 nanophosphors were studied for their photoluminescence to show that the emission color, depending on RE3+, spans a wide range in the Commission Internationale de l'Eclairage (CIE) chromaticity diagram, from blue to deep red via green, yellow, orange, and orange red.

  4. Moessbauer spectra of Eu(III) and Gd(III) complexes of phosphine oxides with chelating perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Masashi, E-mail: takahasi@chem.sci.toho-u.ac.jp; Hirai, Yuya [Toho University (Japan)

    2012-03-15

    The reaction of Ln(ClO{sub 4}){sub 3}{center_dot} nH{sub 2}O with triphenylphosphine oxide (TPPO) in methanol has led to the formation of [Ln(ClO{sub 4}){sub 2}(tppo){sub 4}]ClO{sub 4}{center_dot}MeOH (Ln = Nd, Eu, Gd, Dy, Yb), in which the perchlorate anion acts as a symmetric bidentate. The emission spectra of Eu(III)-TPPO complexes, showing enhancement in the intensity due to the phenyl group, indicate an isotropic electron distribution for the nitrato complex [Eu(NO{sub 3}){sub 3}(tppo){sub 2}(EtOH)]. {sup 151}Eu and {sup 155}Gd Moessbauer spectra of the TPPO complexes also lead to the same conclusion.

  5. U(SMes*)n, (n = 3, 4) and Ln(SMes*)3 (Ln = La, Ce, Pr, Nd): lanthanide(III)/actinide(III) differentiation in agostic interactions and an unprecedented eta3 ligation mode of the arylthiolate ligand, from X-ray diffraction and DFT analysis.

    Science.gov (United States)

    Roger, Mathieu; Barros, Noémi; Arliguie, Thérèse; Thuéry, Pierre; Maron, Laurent; Ephritikhine, Michel

    2006-07-12

    Reaction of U(NEt(2))(4) with HS-2,4,6-(t)Bu(3)C(6)H(2) (HSMes) gave U(SMes)(3)(NEt(2))(py) (1), whereas similar treatment of U[N(SiMe(3))SiMe(2)CH(2)][N(SiMe(3))(2)](2) afforded U(SMes)[N(SiMe(3))(2)](3) (2) and U(SMes)(3)[N(SiMe(3))(2)]. The first neutral homoleptic uranium(IV) thiolate to have been crystallographically characterized, U(SMes)(4) (4), was isolated from the reaction of U(BH(4))(4) and KSMes. The first homoleptic thiolate complex of uranium(III), U(SMes)(3) (5), was synthesized by protonolysis of U[N(SiMe(3))(2)](3) with HSMes in cyclohexane. The crystal structure of 5 exhibits the novel eta(3) ligation mode for the arylthiolate ligand. Comparison of the crystal structure of 5 with those of the isomorphous lanthanide congeners Ln(SMes)(3) (Ln = La, Ce, Pr, and Nd) indicates that the U-S, U-C(ipso)(), and U-C(ortho)() bond lengths are shorter than the corresponding ones in the 4f-element analogues, when taking into account the variation in the ionic radii of the metals. The distance between the uranium and the carbon atoms involved in the U...H-C epsilon agostic interaction of each thiolate ligand is shorter, by approximately 0.05 A, than that expected from a purely ionic bonding model. The lanthanide(III)/actinide(III) differentiation was analyzed by density functional theory (DFT). The nature of the M-S bond is shown to be ionic strongly polarized at the sulfur for M = U and iono-covalent (i.e. strongly ionic with low orbital interaction), for M = Ln. The strength of the U...H-C epsilon agostic interaction is proposed to be controlled by the maximization of the interaction between U(+) and S(-) under steric constraints. The eta(3) ligation mode of the arylthiolate ligand is also obtained from DFT.

  6. Synthesis, luminescence and photometric characteristics of Ca{sub 0.5}La(MoO{sub 4}){sub 2}:Ln{sup 3+} (Ln = Eu, Tb, Dy) phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Rajagopalan [Department of Physics, B. S. Abdur Rahman University, Vandalur, Chennai 600048, Tamil Nadu (India); Thirumalai, Jagannathan, E-mail: jthirumalai@bsauniv.ac.in [Department of Physics, B. S. Abdur Rahman University, Vandalur, Chennai 600048, Tamil Nadu (India); Mahalingam, Venkatakrishnan [Department of Physics, B. S. Abdur Rahman University, Vandalur, Chennai 600048, Tamil Nadu (India); Mantha, Srinivas [Department of ECE, SASTRA University, Tirumalaisamudram, Thanjavur 613401 (India); Lavanya, Manthramoorthy [Department of Physics, B. S. Abdur Rahman University, Vandalur, Chennai 600048, Tamil Nadu (India)

    2015-07-15

    Ca{sub 0.5}La(MoO{sub 4}){sub 2}:Ln{sup 3+} phosphors, where Ln = 4, 8, 12, 16, and 20 mol% of Eu, Tb, or Dy, were successfully synthesized by a conventional solid-state reaction method at 900 °C for 3 h. The Ca{sub 0.5}La(MoO{sub 4}){sub 2}:Ln{sup 3+} phosphors exhibit a scheelite tetragonal crystal structure belonging to the I4{sub 1}/a space group. The strong absorption bands seen in Fourier transform infrared (FTIR) spectra confirm that F{sub 2}(ν{sub 3}) modes of vibration are IR active. The photoluminescence(PL) spectra reveal that, under optical excitation, the as-synthesized phosphors show high intensity narrow emission bands in the red (615 nm), and green (545 nm), and yellow (570 nm) regions for samples doped with Eu{sup 3+}, Tb{sup 3+}, and Dy{sup 3+} ions, respectively. The critical concentrations of Eu{sup 3+}, Tb{sup 3+}, and Dy{sup 3+} as dopants in Ca{sub 0.5}La(MoO{sub 4}){sub 2} were found to be 16, 12 and 12 mol%, respectively. Thereafter, concentration quenching effect occurred in the solid solutions. The fluorescence decay times for the major transitions of {sup 5}D{sub 0} → {sup 7}F{sub 2}, {sup 5}D{sub 4} → {sup 7}F{sub 5}, and {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2} were estimated for different doping concentrations of Eu{sup 3+}, Tb{sup 3+}, and Dy{sup 3+} in Ca{sub 0.5}La(MoO{sub 4}){sub 2}, respectively. To determine the color purity and emission quality of the phosphor, photometric parameters such as color chromaticity coordinates, color correlated temperature (CCT), color rendering index (CRI), and luminous efficacy of radiation (LER) were estimated using the spectral energy distribution functions of the Ca{sub 0.5}La(MoO{sub 4}){sub 2}:Ln{sup 3+} phosphors. - Graphical abstract: Display Omitted - Highlights: • Single crystalline ceramic phosphor Ca{sub 0.5}La(MoO{sub 4}){sub 2}:Ln{sup 3+} were successfully synthesized. • The phosphor exhibits scheelite tetragonal crystal structure with space group I41/a. • Luminescence

  7. Podněty pro uplatňování nonverbálních technik komunikace v pedagogickém procesu

    Directory of Open Access Journals (Sweden)

    Ilona Moravcová

    2015-07-01

    Full Text Available Předložený příspěvek poukazuje na důležitost uplatňování technik nonverbální komunikace v práci pedagogů. Dále představuje relativně nový termín nonverbální inteligence a naznačuje možnosti užití nonverbální komunikace v edukačním, jakož i resocializačním procesu.

  8. Homo- and heteroleptic alkoxycarbene f-element complexes and their reactivity towards acidic N-H and C-H bonds.

    Science.gov (United States)

    Arnold, Polly L; Cadenbach, Thomas; Marr, Isobel H; Fyfe, Andrew A; Bell, Nicola L; Bellabarba, Ronan; Tooze, Robert P; Love, Jason B

    2014-10-14

    The reactivity of a series of organometallic rare earth and actinide complexes with hemilabile NHC-ligands towards substrates with acidic C-H and N-H bonds is described. The synthesis, characterisation and X-ray structures of the new heteroleptic mono- and bis(NHC) cyclopentadienyl complexes LnCp2(L) 1 (Ln = Sc, Y, Ce; L = alkoxy-tethered carbene [OCMe2CH2(1-C{NCHCHN(i)Pr})]), LnCp(L)2 (Ln = Y) , and the homoleptic tetrakis(NHC) complex Th(L)4 4 are described. The reactivity of these complexes, and of the homoleptic complexes Ln(L)3 (Ln = Sc 3, Ce), with E-H substrates is described, where EH = pyrrole C4H4NH, indole C8H6NH, diphenylacetone Ph2CC(O)Me, terminal alkynes RC≡CH (R = Me3Si, Ph), and cyclopentadiene C5H6. Complex 1-Y heterolytically cleaves and adds pyrrole and indole N-H across the metal carbene bond, whereas 1-Ce does not, although 3 and 4 form H-bonded adducts. Complexes 1-Y and 1-Sc form adducts with CpH without cleaving the acidic C-H bond, 1-Ce cleaves the Cp-H bond, but 2 reacts to form the very rare H(+)-[C5H5](-)-H(+) motif. Complex 1-Ce cleaves alkyne C-H bonds but the products rearrange upon formation, while complex 1-Y cleaves the C-H bond in diphenylacetone forming a product which rearranges to the Y-O bonded enolate product.

  9. Near-infrared photoluminescence in La0.98AlO3: 0.02Ln3+(Ln = Nd/Yb) for sensitization of c-Si solar cells

    Science.gov (United States)

    Sawala, N. S.; Koparkar, K. A.; Bajaj, N. S.; Omanwar, S. K.

    2016-05-01

    The host matrix LaAlO3 was synthesized by conventional solid state reaction method in which the Nd3+ ions and Yb3+ ions successfully doped at 2mol% concentrations. The phase purity was confirmed by X ray powder diffraction (XRD) method. The photoluminescence (PL) properties were studied by spectrophotometer in near infra red (NIR) and ultra violet visible (UV-VIS) region. The Nd3+ ion doped LaAlO3 converts a visible (VIS) green photon (587 nm) into near infrared (NIR) photon (1070 nm) while Yb3+ ion doped converts ultra violet (UV) photon (221 nm) into NIR photon (980 nm). The La0.98AlO3: 0.02Ln3+(Ln = Nd / Yb) can be potentiality used for betterment of photovoltaic (PV) technology. This result further indicates its potential application as a luminescence converter layer for enhancing solar cells performance.

  10. Synthesis and ionic conductivity of new high Li ion content garnets, LnSr{sub 2}Ta{sub 2}Li{sub 7}O{sub 12} (Ln = La, Pr, Nd, Sm, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Howard, M.A. [School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom); Clemens, O. [School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom); Technische Universität Darmstadt, Joint Research Laboratory Nanomaterials, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Parvathy, A.S. [Technische Universität Darmstadt, Joint Research Laboratory Nanomaterials, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Anderson, P.A. [School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom); Slater, P.R., E-mail: p.r.slater@bham.ac.uk [School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2016-06-15

    In this paper we report the synthesis and Li ion conductivity of the new high Li content garnet phases LnSr{sub 2}Ta{sub 2}Li{sub 7}O{sub 12} (Ln = La, Pr, Nd, Sm or Gd). Close inspection of the X-ray diffraction patterns indicate that these systems are mostly composed of the ordered tetragonal garnet phase, along with a small amount of cubic garnet. The presence of a small amount of cubic garnet phase can most likely be correlated with partial Li loss on synthesis as well as some degree of H{sup +}/Li{sup +} exchange. The latter was supported by results from variable temperature X-ray diffraction studies and thermogravimetric analysis. The adoption of the tetragonal garnet structure by these new systems highlights further that in order to accommodate 7 Lithium ions within the garnet structure, then cation ordering must occur to prevent short Li–Li interactions. In line with other tetragonal garnet systems, the Li ion conductivity is shown to be low, as a result of this ordered Li distribution. - Highlights: • The successful synthesis of new LnSr{sub 2}Ta{sub 2}Li{sub 7}O{sub 12} (Ln = La, Pr, Nd, Sm, Gd) garnet phases. • The demonstration that these “Li7” garnets all adopt tetragonal symmetry consistent with Li ordering. • The demonstration that these systems are susceptible to moisture from the air, which leads to partial H/Li Exchange.

  11. High-pressure synthesis and magnetic behavior of A-site columnar-ordered double perovskites, LnMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} (Ln = Sm, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Shimura, Gen; Niwa, Ken; Shirako, Yuichi; Hasegawa, Masashi [Department of Crystalline Materials Science, Nagoya University, 464-8601, Nagoya (Japan)

    2017-01-26

    A-site columnar-ordered double perovskites, LnMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} (Ln = Sm, Gd), were successfully synthesized under high pressure and high temperature (6 GPa, 1375 K). From the synchrotron powder X-ray diffraction patterns, all of the diffraction peaks can be indexed by the P4{sub 2}/nmc space group with lattice parameters a, c ∼ 2a{sub p} (a{sub p}: primitive cubic perovskite lattice) and no ordering of the B-site cations. Rietveld analysis of the synchrotron powder X-ray diffraction patterns and Curie-Weiss fitting of their magnetizations reveal that the ionic formulae of these perovskites are Ln{sup 3+}Mn{sup 2+}(Ga{sup 3+}{sub 0.5}Ti{sup 4+}{sub 0.5}){sub 2}O{sup 2-}{sub 6}. SmMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} shows canted-antiferromagnetic behavior, whereas GdMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} exhibits two different magnetic states at low temperature depending on the applied magnetic field and shows an unusual magnetization curve. These magnetic behaviors originate by decreasing the antiferromagnetic interaction by substituting Ga{sup 3+}(d{sup 10}) for Ti{sup 4+}(d{sup 0}) and by decreasing the ferromagnetic interaction between columnar-ordered Ln{sup 3+} and Mn{sup 2+}. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. In vitro studies of lanthanide complexes for the treatment of osteoporosis.

    Science.gov (United States)

    Mawani, Yasmin; Cawthray, Jacqueline F; Chang, Stanley; Sachs-Barrable, Kristina; Weekes, David M; Wasan, Kishor M; Orvig, Chris

    2013-05-07

    Lanthanide ions, Ln(III), are of interest in the treatment of bone density disorders because they are found to accumulate preferentially in bone (in vivo), have a stimulatory effect on bone formation, and exhibit an inhibitory effect on bone degradation (in vitro), altering the homeostasis of the bone cycle. In an effort to develop an orally active lanthanide drug, a series of 3-hydroxy-4-pyridinone ligands were synthesized and eight of these ligands (H1 = 3-hydroxy-2-methyl-1-(2-hydroxyethyl)-4-pyridinone, H2 = 3-hydroxy-2-methyl-1-(3-hydroxypropyl)-4-pyridinone, H3 = 3-hydroxy-2-methyl-1-(4-hydroxybutyl)-4-pyridinone, H4 = 3-hydroxy-2-methyl-1-(2-hydroxypropyl)-4-pyridinone, H5 = 3-hydroxy-2-methyl-1-(1-hydroxy-3-methylbutan-2-yl)-4-pyridinone, H6 = 3-hydroxy-2-methyl-1-(1-hydroxybutan-2-yl)-4-pyridinone, H7 = 1-carboxymethyl-3-hydroxy-2-methyl-4-pyridinone, H8 = 1-carboxyethyl-3-hydroxy-2-methyl-4-pyridinone) were coordinated to Ln(3+) (Ln = La, Eu, Gd, Lu) forming stable tris-ligand complexes (LnL(3), L = 1(-), 2(-), 3(-), 4(-), 5(-), 6(-), 7(-) and 8(-)). The dissociation (pK(an)) and metal ligand stability constants (log β(n)) of the 3-hydroxy-4-pyridinones with La(3+) and Gd(3+) were determined by potentiometric titrations, which demonstrated that the 3-hydroxy-4-pyridinones form stable tris-ligand complexes with the lanthanide ions. One phosphinate-EDTA derivative (H(5)XT = bis[[bis(carboxymethyl)amino]methyl]phosphinate) was also synthesized and coordinated to Ln(3+) (Ln = La, Eu, Lu), forming the potassium salt of [Ln(XT)](2-). Cytotoxicity assays were carried out in MG-63 cells; all the ligands and metal complexes tested were observed to be non-toxic to this cell line. Studies to investigate the toxicity, cellular uptake and apparent permeability (P(app)) of the lanthanide ions were conducted in Caco-2 cells where it was observed that [La(XT)](2-) had the greatest cell uptake. Binding affinities of free lanthanide ions (Ln = La, Gd and Lu), metal

  13. Hydrothermal synthesis and photoluminescent properties of hierarchical GdPO4·H2O:Ln3+ (Ln3+ = Eu3+, Ce3+, Tb3+) flower-like clusters

    Science.gov (United States)

    Amurisana, Bao.; Zhiqiang, Song.; Haschaolu, O.; Yi, Chen; Tegus, O.

    2018-02-01

    3D hierarchical GdPO4·H2O:Ln3+ (Ln3+ = Eu3+, Ce3+, Tb3+) flower clusters were successfully prepared on glass slide substrate by a simple, economical hydrothermal process with the assistance of disodium ethylenediaminetetraacetic acid (Na2H2L, where L4- = (CH2COO)2N(CH2)2N(CH2COO)24-). In this process, Na2H2L was used as both a chelating agent and a structure-director. The hierarchical flower clusters have an average diameter of 7-12 μm and are composed of well-aligned microrods. The influence of the molar ratio of Na2H2L/Gd3+ and reaction time on the morphology was systematically studied. A possible crystal growth and formation mechanism of hierarchical flower clusters is proposed based on the evolution of morphology as a function of reaction time. The self-assembled GdPO4·H2O:Ln3+ superstructures exhibit strong orange-red (Eu3+, 5D0 → 7F1), green (Tb3+, 5D4 → 7F5) and near ultraviolet emissions (Ce3+, 5d → 7F5/2) under ultraviolet excitation, respectively. This study may provide a new channel for building hierarchically superstructued oxide micro/nanomaterials with optical and new properties.

  14. Twinned CsLn{sub 2}F{sub 7} compounds (Ln=Nd, Gd, Tb, Er, Yb). The role of a highly symmetrical cation lattice with an arrangement analogous to the Laves phase MgZn{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Karen [Forschungszentrum Juelich GmbH, Juelich (Germany). Juelich Centre for Neutron Science-2; Khaidukov, Nicholas [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation); Grzechnik, Andrzej [RWTH Aachen Univ. (Germany). Inst. for Crystallography

    2016-07-01

    The occurrence of twinning can often be related to higher symmetrical structures. Fluorides are frequently twinned due to their close relation to high symmetry structures like fluoride, tysonite or pyrochlores. The series of compounds CsLn{sub 2}F{sub 7} is no exception. We refined the structures of the twinned compounds with Ln=Nd, Gd, Tb, Er, Yb in space group P112{sub 1}/b. An analysis of the pseudosymmetry of the resulting structures shows a highly symmetrical cation partial structure with a cation distribution similar to the one in the hexagonal Laves phase MgZn{sub 2}. Several other compounds ALn{sub 2}F{sub 7}, which have been described in the literature, show a similar cation array. The diversity of different space groups which have been reported for ALn{sub 2}F{sub 7} compounds can be better understood using group-subgroup relationships assuming the hypothetical structure of the cation array with space group P6{sub 3}/mmc as aristotype. Furthermore, the twinning is easily understood on the basis of the lost symmetry operations in the symmetry reduction from point group 6/mmm, e.g. to 2/m in the case of the CsLn{sub 2}F{sub 7} compounds.

  15. A family of 3d-4f octa-nuclear [Mn(III)(4)Ln(III)(4)] wheels (Ln = Sm, Gd, Tb, Dy, Ho, Er, and Y): synthesis, structure, and magnetism.

    Science.gov (United States)

    Li, Mengyuan; Lan, Yanhua; Ako, Ayuk M; Wernsdorfer, Wolfgang; Anson, Christopher E; Buth, Gernot; Powell, Annie K; Wang, Zheming; Gao, Song

    2010-12-20

    We present the syntheses, crystal structures, and magnetochemical characterizations for a family of isostructural [Mn(4)Ln(4)] compounds (Ln = Sm, Gd, Tb, Dy, Ho, Er, and Y). They were prepared from the reactions of formic acid, propionic acid, N-n-butyl-diethanolamine, manganese perchlorate, and lanthanide nitrates under the addition of triethylamine in MeOH. The compounds possess an intriguing hetero-octanuclear wheel structure with four Mn(III) and four Ln(III) ions alternatively arranged in a saddle-like ring, where formate ions act as key carboxylate bridges. In the lattice, the molecules stack into columns in a quasi-hexagonal arrangement. Direct current (dc) magnetic susceptibility measurements indicated the depopulation of the Stark components at low temperature and/or very weak antiferromagnetic interactions between magnetic centers. The zero-field alternating current (ac) susceptibility studies revealed that the compounds containing Sm, Tb, and Dy showed frequency-dependent out-of-phase signals, indicating they are single-molecule magnets (SMMs). Magnetization versus applied dc field sweeps on a single crystal of the Dy compound down to 40 mK exhibited hysteresis depending on temperatures and field sweeping rates, further confirming that the Dy compound is a SMM. The magnetization dynamics of the Sm and Y compounds investigated under dc fields revealed that the relaxation of the Sm compound is considered to be dominated by the two-phonon (Orbach) process while the Y compound displays a multiple relaxation process.

  16. Effects of Different Forging Processes on Microstructure Evolution for 316LN Austenitic Stainless Steel

    Science.gov (United States)

    Sui, Dashan; Zhu, Lingling; Wang, Tao; Zhang, Peipei; Cui, Zhenshan

    2017-10-01

    Forging experiments were designed and carried out on a 3150 kN hydraulic press to investigate the effects of different processes on the microstructure evolution for 316LN steel. The forging processes included single-pass (upsetting) and multipass (stretching) deformations, and the experimental results indicated that the average grain size varied with forging processes. Moreover, the size had distinct differences at different positions in the workpiece. Meanwhile, numerical simulations were implemented to study the influence of temperature, strain, and strain rate on microstructure evolution. The results of experiments and simulations comprehensively demonstrated that dynamic, static, and meta-dynamic recrystallization could coexist in the hot forging process and that the recrystallization process could easily occur under the conditions of higher temperature, larger strain, and higher strain rate. Moreover, the temperature had more significant influence on both recrystallization and grain growth. A higher temperature could not only promote the recrystallization but also speed up the grain growth. Therefore, a lower temperature is beneficial to obtain refinement grains on the premise that the recrystallization can occur completely.

  17. Pairing in the BCS and LN approximations using continuum single particle level density

    Energy Technology Data Exchange (ETDEWEB)

    Id Betan, R.M., E-mail: idbetan@ifir-conicet.gov.ar [Instituto de Física Rosario (CONICET-UNR), Bv. 27 de Febrero 210 bis, S2000EZP Rosario (Argentina); Facultad de Ciencias Exactas, Ingeniería y Agrimensura (UNR), Av. Pellegrini 250, S2000BTP Rosario (Argentina); Instituto de Estudios Nucleares y Radiaciones Ionizantes (UNR), Riobamba y Berutti, S2000EKA Rosario (Argentina); Repetto, C.E. [Instituto de Física Rosario (CONICET-UNR), Bv. 27 de Febrero 210 bis, S2000EZP Rosario (Argentina); Facultad de Ciencias Exactas, Ingeniería y Agrimensura (UNR), Av. Pellegrini 250, S2000BTP Rosario (Argentina)

    2017-04-15

    Understanding the properties of drip line nuclei requires to take into account the correlations with the continuum spectrum of energy of the system. This paper has the purpose to show that the continuum single particle level density is a convenient way to consider the pairing correlation in the continuum. Isospin mean-field and isospin pairing strength are used to find the Bardeen–Cooper–Schrieffer (BCS) and Lipkin–Nogami (LN) approximate solutions of the pairing Hamiltonian. Several physical properties of the whole chain of the Tin isotope, as gap parameter, Fermi level, binding energy, and one- and two-neutron separation energies, were calculated and compared with other methods and with experimental data when they exist. It is shown that the use of the continuum single particle level density is an economical way to include explicitly the correlations with the continuum spectrum of energy in large scale mass calculation. It is also shown that the computed properties are in good agreement with experimental data and with more sophisticated treatment of the pairing interaction.

  18. Digitální informační zdroje v oboru psychologie

    OpenAIRE

    Kotrlová, Jindřiška

    2009-01-01

    Cílem rigorózní práce je analyzovat a vyhodnotit digitální informační zdroje v oboru psychologie komerčně nebo volně dostupné v prostředí World Wide Web. Úvodní část práce obsahuje charakteristiku oboru a jeho informační potřeby. Jsou zmíněny instituce, kde vědecká informace vzniká a kde je využívána. V druhé části je pojednáno o problematice elektronického publikování a o terminologických otázkách. Třetí stěžejní část je věnována prezentaci výsledků analýzy a hodnocení vybraných reprezentant...

  19. Classification of PD sources in HV cables using neural networks and the LN-FDTD method

    Energy Technology Data Exchange (ETDEWEB)

    Barros, W.H.; Oliveira, R.M.; Sobrinho, C.L.; Leite, R.C. [Univ. Federal do Para, Para (Brazil). Dept. of Computational and Electrical Engineering

    2008-07-01

    Partial discharges can be generated by the presence of several defects, and are often the cause of failures in electrical equipment insulators. In this study, a local non-orthogonal finite difference time-domain method (LN-FDTD) was used to simulate the sources of partial discharges in a high voltage coaxial cable model. The artificial neural network (ANN) technique used a Marquandt-Levenberg training algorithm to detect and classify cable PD sources. A set of harmonics obtained from the difference between the registered signals in the time domain was used as part of the training procedure. A failure was inserted on an electrical cable in each simulation in order to obtain the correlated data. Input signals were injected using a voltage pulse represented by a Gaussian function. A total of 90 simulations were conducted to generate 360 data groups in order to consider 6 different types of failures. Results of the study showed that the method can be used to detect and classify partial discharges in cables. 12 refs., 21 figs.

  20. AC surface flashover strength and barrier effect of LN 2 for HTS transformer with simulated electrode

    Science.gov (United States)

    Joung, Jong-Man; Baek, Seung-Myeong; Kim, Hae-Jong; Kim, Sang-Hyun

    2003-10-01

    In the response to an increasing demand for electrical energy, much effort aimed to develop and commercialise HTS power equipments is going on around the world. For the development, it is necessary to establish the dielectric technology in LN 2. Hence many types of dielectric tests should be carried out to understand the dielectric phenomena at cryogenic temperature and to gather various dielectric data. Among the many types dielectric tests, the characteristic of surface flashover and the barrier effect were conducted with the simulated electrode after analysing the insulating configuration of the pancake-coil-type HTS transformer. The influence of a barrier on the dielectric strength was measured according to the size of the barrier, the position of the barrier and the effect of the back-electrode. It was shown that the effectiveness, namely the ratio of the breakdown voltage in presence of barrier to the voltage without barrier, is highest when the barrier is placed at the needle electrode side. The effect increased up to 1.8 times when collar length is 10 mm. The flashover characteristic with back-electrode was remarkably lower than the characteristic without one in the case the electrodes located at the same surface of dielectric plate. On the contrary, in the case the barrier was placed between the electrodes, the characteristic was even improved slightly.

  1. Corrosion Fatigue Behavior of 316LN SS in Acidified Sodium Chloride Solution at Applied Potential

    Science.gov (United States)

    Poonguzhali, A.; Pujar, M. G.; Mallika, C.; Mudali, U. Kamachi

    2015-05-01

    The influence of acidified 1 M NaCl solution by addition of 2 ml/L of HCl on the cyclic plastic deformation of AISI Type 316LN SS containing 0.07 wt.% and 0.22 wt.% N was investigated as a function of the applied potentials. The corrosion fatigue (CF) behavior of stainless steel (SS) was explained vis-a-vis the dislocation behavior, the propensity to form microcracks, and the evolution of the current transients based on the studies carried out at both room-temperature and boiling conditions. CF experiments were conducted using round tensile specimens at a stress ratio of 0.5 and a frequency of 0.1 Hz. Two different kinds of damage mechanisms were observed (I) the damage mechanism in the stable-passive state was correlated with the localization of the anodic dissolution due to a depassivation-repassivation process, whereas (II) the cyclic stress induced pitting corrosion in the metastable pitting state, which resulted in formation of microcracks. The study of the microcracking process and its evolution is a key to the physical mechanism by which the fatigue life of stainless steels would be affected in an aqueous corrosive solution under the applied potential.

  2. Optimization of hybrid laser - TIG welding of 316LN steel using response surface methodology (RSM)

    Science.gov (United States)

    Ragavendran, M.; Chandrasekhar, N.; Ravikumar, R.; Saxena, Rajesh; Vasudevan, M.; Bhaduri, A. K.

    2017-07-01

    In the present study, the hybrid laser - TIG welding parameters for welding of 316LN austenitic stainless steel have been investigated by combining a pulsed laser beam with a TIG welding heat source at the weld pool. Laser power, pulse frequency, pulse duration, TIG current were presumed as the welding process parameters whereas weld bead width, weld cross-sectional area and depth of penetration (DOP) were considered as the process responses. Central composite design was used to complete the design matrix and welding experiments were conducted based on the design matrix. Weld bead measurements were then carried out to generate the dataset. Multiple regression models correlating the process parameters with the responses have been developed. The accuracy of the models were found to be good. Then, the desirability approach optimization technique was employed for determining the optimum process parameters to obtain the desired weld bead profile. Validation experiments were then carried out from the determined optimum process parameters. There was good agreement between the predicted and measured values.

  3. Effects of pre-creep on the dislocations of 316LN Austenite stainless steel

    Science.gov (United States)

    Pei, Hai-xiang; Hui, Jun; Hua, Hou; Feng, Zai-xin; Xu, Xiao-long

    2017-09-01

    The 316LN Austenite stainless steels (316LNASS) were pre-creep treated, the evolution of microstructure were investigated. The samples were pre-creep at 593 K and from 500 to 2000 h at 873 K with a stress in the range of 20 to 150 MPa, Then the evolution of microstructure and precipitation were investigated by optical microscope (OM), and transmission electron microscope (TEM). The results show that the crystal surface slipping resulted in dislocations and original dislocations decomposition during the pre-creep process, and generate quadrilateral or hexagonal dislocation network was obviously. The sub-grain boundary gradually became narrow with the increasing of pre-creep treatment time and temperature. When the pre-creep temperature was 593 K and 873 K, dislocation network gradually disappear with the increasing of pre-creep time and load. When the pre-creep temperature was 873 K under 120 MPa, and the treatment time was 2000 h, the hexagonal dislocation network (HDN) would completely disappeared. When the pre-creep temperature was 593 K under 20 MPa, and the treatment time was 500 h, the quadrilateral dislocation network (QDN) would completely disappeared.

  4. Identifikace vhodných vlastností leadra v globální organizaci

    OpenAIRE

    Kuric, Matej

    2017-01-01

    Diplomová práce se zabývá problematikou leadershipu v mezinárodní společnosti. V teoretické části definuje leadera, poukazuje na rozdíly mezi manažerem a leaderem, rozebírá vlastnosti leadera dnešní doby z pozice různých teoretických přístupů. V praktické části analyzuje nastavení leadershipu ve vybrané společnosti a získané poznatky porovnává s teoretickými definicemi. Na základě získaných výsledků navrhuje konkrétní způsoby rozvoje vybraných osobnostních vlastností s akceptováním regionální...

  5. A Study on Thermal Desorption of Deuterium in D-loaded SS316LN for ITER Tritium Removal System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Myungchul; Kim, Heemoon; Ahn, Sangbok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jaeyong; Lee, Sanghwa; LanAhn, Nguyen Thi [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    Because Type B radwaste includes tritium on its inside, especially at vicinity of surface, tritium removal from the radwaste is a matter of concern in terms of the radwaste processes. Tritium behavior in materials is related with temperature. Considering a diffusion process, it is expected that tritium removal efficiency is enhanced with increasing baking temperature. However, there is a limitation about temperature due to facility capacity and economic aspect. Therefore, it is necessary to investigate the effect of temperature on the desorption behavior of Tritium in ITER materials. TDS analysis was performed in SS316LN loaded at 120, 240 and 350 °C. D2 concentration and the desorption peak temperature increased with increasing loading temperature. Using peak shift method with three ramp rates of 0.166, 0.332, and 0.5 °C/sec, trap activation energy of D in SS316LN loaded at 350 °C was 56 kJ/mol.

  6. Effect of boron addition and ESR process on the creep properties of type 316L(N) stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, W. K.; Kim, D. H.; Jang, J. S.; Kook, I. H.; Ryu, W. S. [KAERI, Taejon (Korea, Republic of)

    1999-10-01

    The effects of B-addition and ESR(electroslag remelting) process on the creep properties of 316L(N) stainless steel were investigated at 550 deg C in air. High temperature tensile strength for three heats was similar, but creep rupture time of B-doped and ESR-processed 316L(N) steels increased significantly in comparison with B-undoped steels. Also, the creep rupture elongation increased and minimum creep rate decreased inversely. Cross section of crept specimen showed the typical wedge cracks regardless of B-addition or ESR. The size and spacing of grain boundary cavitation in B-doped and ESR-processed steels were smaller than those of B-undoped steels. It was concluded that 0.0025% boron addition increases creep rupture time by delaying the onset of the tertiary stage due to suppression of grain boundary cavitation and wedge cracking.

  7. La islamofobia como recurso político: el caso pro-Köln (PRO-NRW

    Directory of Open Access Journals (Sweden)

    Guerrero Enterría, Arturo

    2008-12-01

    Full Text Available This article seeks to analyse, from the case study of the Pro-Köln party, how Islamophobia is used as a resource by some parties on the extreme right in Europe to obtain political returns and electoral support. Using an analysis of the genesis of the party and its electoral program as a starting point, the study dismantles theargument that this party’s main objective is to fight against the Islamisation of Europe, and shows that this is only one means to articulate an ultra-rightist political discourse and that its attempt to stop the construction of the mosque in Köln is only window-dressing to conquer the votes of the citizenry.

  8. A stable porous anionic metal-organic framework for luminescence sensing of ln(3+) ions and detection of nitrobenzene.

    Science.gov (United States)

    Qin, Jun-Sheng; Bao, Shao-Juan; Li, Peng; Xie, Wei; Du, Dong-Ying; Zhao, Liang; Lan, Ya-Qian; Su, Zhong-Min

    2014-03-01

    A hexagonal channel-based porous anionic metal-organic framework was successfully constructed. IFMC-3 is stable in air and acidic/basic aqueous solutions at room temperature, and constitutes a selective luminescent sensing material for Ln(3+) ions and a recyclable probe for the sensitive detection of nitrobenzene. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Aqueous Binary Lanthanide(III) Nitrate Ln(NO3)3 Electrolytes Revisited: Extended Pitzer and Bromley Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sayandev; Campbell, Emily L.; Neiner, Doinita; Pence, Natasha; Robinson, Troy; Levitskaia, Tatiana G.

    2015-09-11

    To date, only limited thermodynamic models describing activity coefficients of the aqueous solutions of lanthanide ions are available. This work expands the existing experimental osmotic coefficient data obtained by classical isopiestic technique for the aqueous binary trivalent lanthanide nitrate Ln(NO3)3 solutions using a combination of water activity and vapor pressure osmometry measurements. The combined osmotic coefficient database for each aqueous lanthanide nitrate at 25°C, consisting of literature available data as well as data obtained in this work, was used to test the validity of Pitzer and Bromley thermodynamic models for the accurate prediction of mean molal activity coefficients of the Ln(NO3)3 solutions in wide concentration ranges. The new and improved Pitzer and Bromley parameters were calculated. It was established that the Ln(NO3)3 activity coefficients in the solutions with ionic strength up to 12 mol kg-1 can be estimated by both Pitzer and single-parameter Bromley models, even though the latter provides for more accurate prediction, particularly in the lower ionic strength regime (up to 6 mol kg-1). On the other hand for the concentrated solutions, the extended three-parameter Bromley model can be employed to predict the Ln(NO3)3 activity coefficients with remarkable accuracy. The accuracy of the extended Bromley model in predicting the activity coefficients was greater than ~95% and ~90% for all solutions with the ionic strength up to 12 mol kg-1 and and 20 mol kg-1, respectively. This is the first time that the activity coefficients for concentrated lanthanide solutions have been predicted with such a remarkable accuracy.

  10. HOMO- AND HETERONUCLEAR COMPLEXES OF COPPER (II WITH SCHIFF BASE OBTAINED ON THE BASE OF 2-HYDROXY-3-CARBOXYNAPHTALDEHYDE

    Directory of Open Access Journals (Sweden)

    A.G. Lazarescu

    2006-06-01

    Full Text Available The complexes of general formula Cu(H2L (II; [CuLn(L(NO3(H2On] (where H4L=N,NI-bis[2- hydroxy(3-carboxynaphtalidene]ethylenediamine; Ln: Nd, n=6 (III; Eu, n=4 (IV; Gd, n=6 (V have been synthesized and investigated by different methods (IR spectroscopy, TG analysis and magnetochemistry. The coordination set of complex generators are Cu(N2O2 and Ln(O8-9. The effective magnetic moment values, μeff, at 300 K are: 1.78 (II, 3.22 (III, 6.44 (V B.M. The temperature dependence (300-2 K of magnetic susceptibility of [CuNd(L(NO3(H2O6] indicates the antiferromagnetic interaction between metal ions.

  11. HOMO- AND HETERONUCLEAR COMPLEXES OF COPPER (II) WITH SCHIFF BASE OBTAINED ON THE BASE OF 2-HYDROXY-3-CARBOXYNAPHTALDEHYDE

    OpenAIRE

    A.G. Lazarescu; T.C. Popa

    2006-01-01

    The complexes of general formula Cu(H2L) (II); [CuLn(L)(NO3)(H2O)n] (where H4L=N,NI-bis[2- hydroxy(3-carboxynaphtalidene)]ethylenediamine; Ln: Nd, n=6 (III); Eu, n=4 (IV); Gd, n=6 (V) have been synthesized and investigated by different methods (IR spectroscopy, TG analysis and magnetochemistry). The coordination set of complex generators are Cu(N2O2) and Ln(O8-9). The effective magnetic moment values, μeff, at 300 K are: 1.78 (II), 3.22 (III), 6.44 (V) B.M. The temperature dependence (300-2 K...

  12. A [Cyclentetrakis(methylene)]tetrakis[2-hydroxybenzamide]Ligand That Complexes and Sensitizes Lanthanide(III) Ions

    Energy Technology Data Exchange (ETDEWEB)

    D' Aleo, Anthony; Xu, Jide; Do, King; Muller, Gilles; Raymond, Kenneth N.

    2009-04-30

    The synthesis of a cyclen derivative containing four isophthalamide groups (L{sup 1}) is described. The spectroscopic properties of the Ln(III) complexes of L{sup 1} (Ln = Gd, Tb, Yb, Eu) reveal changes of the UV/visible absorption, circular dichroism absorption, luminescence and circularly polarized luminescence properties. It is shown that at least two metal complex species are present in solution, whose relative amounts are pH dependent. When at pH > 8.0, an intense long lived emission is observed (for [L{sup 1}Tb] and [L{sup 1}Yb]) while at pH < 8.0, a weaker, shorter-lived species predominates. Unconventional Ln(III) emitters (Pr, Nd, Sm, Dy and Tm) were sensitized in basic solution, both in the visible and in the near infra-red, to measure the emission of these ions.

  13. Photoluminescence properties of lanthanide-organic frameworks (LnOFs) with thiophene-2,5-dicarboxylate and acetate

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jing; Wei, Qing; Xie, Gang; Chen, Sanping [Key Lab. of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest Univ., Xi' an, Shaanxi (China); Zhang, Sheng [Key Lab. of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest Univ., Xi' an, Shaanxi (China); College of Chemistry and Chemical Engineering, Baoji Univ. of Arts and Science, Baoji, Shaanxi (China)

    2017-07-17

    S-heterocyclic dicarboxylic acid, thiophene-2,5-dicarboxylic acid (H{sub 2}TDC), was employed to construct a series of lanthanide-organic frameworks (LnOFs) with coligand acetate, formulated as [Ln(TDC)(OAc)(H{sub 2}O)]{sub n} [Ln = Eu (1), Tb (2), Gd (3), Dy (4), Sm (5)] under hydrothermal conditions. Structure analysis reveals that 1-5 have dinuclear 3D metal organic frameworks (MOFs), in which TDC{sup 2-} and OAc{sup -} display (κ{sup 1}-κ{sup 1})-(κ{sup 1}-κ{sup 1})-μ{sub 4} and (κ{sup 2}-κ{sup 1})-μ{sub 2} coordination fashions, respectively. The dehydrated products of all compounds show high thermal stability above 410 C. As for 1, 2, 4, and 5, the photoluminescence analyses exhibit characteristic luminescence emission bands of the corresponding lanthanide ions in the visible region. In particular, compound 2 displays bright green luminescence in the solid state with {sup 5}D{sub 4} lifetime of 0.510 ms and relative high overall quantum yield of 16 %, based on an ideal energy gap between the lowest triplet state energy level of H{sub 2}TDC ligand and the {sup 5}D{sub 4} state energy level of Tb{sup 3+}. The energy transfer mechanisms in compounds 1 and 2 were also discussed. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. A Conceptual Framework for the Electronic Performance Support Systems within IBM Lotus Notes 6 (LN6 Example

    Directory of Open Access Journals (Sweden)

    Servet BAYRAM

    2005-10-01

    Full Text Available A Conceptual Framework for the Electronic PerformanceSupport Systems within IBM Lotus Notes 6 (LN6 Example Assoc. Prof. Dr. Servet BAYRAM Computer Education & Instructional Technologies Marmara University, TURKEYsbayram@marmara.edu.tr ABSTRACT The concept of Electronic Performance Support Systems (EPSS is containing multimedia or computer based instruction components that improves human performance by providing process simplification, performance information and decision support system. EPSS has become a hot topic for organizational development, human resources, performance technology, training, and educational development professionals. A conceptual framework of EPSS is constructed under five interrelated and interdependent domains for educational implications. The domains of the framework are online collaboration, cost-effectiveness, motivation, service management, and performance empowering. IBM Lotus Notes 6 (LN6 is used as an example application tool to illustrate the power of this framework. The framework describes a set of relevant events based upon deductive analyses for improving our understanding of the EPSS and its implications on education and training. The article is also pointed out that there are some similarities between the EPSS’ and the LN6’s specific features within this conceptual framework. It can provide some guidelines and benefits to researchers, educators, and designers as well.

  15. Syntheses, structure and properties of three-dimensional pillared-layer Ag(I)-Ln(III) heterometallic coordination polymers based on mixed isonicotinate and hemimellitate ligands

    Science.gov (United States)

    Li, Xinfa; Cao, Rong

    2012-12-01

    Three pillared-layer 4d-4f Ag(I)-Ln(III) heterometallic coordination polymers (HCPs), formulated as [Ln2Ag(hma)2(ina)(H2O)2]n nH2O [Ln=La(1), Pr(2), Nd(3); Hina=isonicotinic acid, H3hma=hemimellitic acid], have been synthesized under hydrothermal conditions. Single-crystal and powder X-ray diffractions confirm that they are isostructural, which features a three-dimensional (3D) pillared-layer heterometallic structure built upon the strictly alternate arrangement of lanthanide-organic layers and [Ag(ina)] pillars. The layers and pillars are connected to each other by Ln-O and Ag-O coordination bonds. The photoluminescent property of the Nd derivative (3) has also been investigated.

  16. 20 The Tools - 03 Self-Efficacy Questionnaires - TfLN Self-Efficacy Questionnaires: Rationale (01 Guide to Self-Efficacy)

    OpenAIRE

    TfLN-Transforming Perspectives project

    2007-01-01

    Explanation of what 'self-efficacy' is taken to mean in terms of student self-perception of ability, and relating that to the literature, current academic discourse and the use of the term in the TfLN context.

  17. The effect of lanthanides on color properties of the (Bi2O30.7(Ln2O30.3 compounds

    Directory of Open Access Journals (Sweden)

    Šulcová P.

    2008-01-01

    Full Text Available (Bi2O30.7(Ln2O30,3 solid solutions were synthesized as new inorganic yellow and orange pigments and their color properties have been investigated as possible ecological materials. The pigments were prepared by the solid state reaction of mixed oxides (Bi2O30.7(Ln2O30.3 of various rare earth cations (Ln = Eu, Gd, Tm, Yb and Lu. All the synthesized pigment samples were found to have color coordinates, low a* and high b* and exhibit the color from pale light yellow to orange. Reflectance spectra of the samples show high reflectance percentage in the 600 - 700 nm range. Characterization of the (Bi2O30.7(Ln2O30,3 solid solutions suggests that they have a potential to be alternative yellow colorants for paints, inks, plastics, and ceramics.

  18. Metal–organic frameworks assembled from lanthanide and 2,5-pyridinedicaboxylate with cubane-like [Ln{sub 4}(OH){sub 4}] building units

    Energy Technology Data Exchange (ETDEWEB)

    Abdelbaky, Mohammed S.M. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain); Amghouz, Zakariae, E-mail: amghouz.uo@uniovi.es [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain); Servicios Científico-Técnicos, University of Oviedo—CINN, Oviedo 33006 (Spain); Fernández-Zapico, Eva; García-Granda, Santiago; García, José R. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, University of Oviedo—CINN, Oviedo 33006 (Spain)

    2015-09-15

    tremendous attention due to the unique characteristic of lanthanide cations, such as variable coordination numbers and geometries which often lead to novel complex structures, and also to their magnetic and photoluminescence properties. Herein, three LOFs formulated as [Ln{sub 4}(OH){sub 4}(25p){sub 4}(H{sub 2}O){sub 3}]·H{sub 2}O (Ln=Y, Yb) and [Y{sub 6}(OH){sub 8}(25p){sub 5}(H{sub 2}O){sub 2}] have been obtained by hydrothermal method and characterized, and the photoluminescence properties of the Eu and Tb doped compounds are discussed. - Highlights: • Three novel LnOFs has been synthesized and characterized. • Crystal structures are based on tetranuclear cuban-like [Ln{sub 4}(OH){sub 4}]{sup 8+} clusters. • 25pYb and 25pY-1 are based on isolated [Ln{sub 4}(OH){sub 4}]{sup 8+} clusters. • 25pY-2 is based on infinite inorganic chains built up from [Y{sub 4}(OH){sub 4}]{sup 8+} clusters. • Photoluminescence studies show strong red and green light emissions.

  19. Homoleptic lanthanide 1,2,3-triazolates (∞)(2–3)[Ln(Tz*)3] and their diversified photoluminescence properties.

    Science.gov (United States)

    Rybak, J-Christoph; Meyer, Larissa V; Wagenhöfer, Julian; Sextl, Gerhard; Müller-Buschbaum, Klaus

    2012-12-17

    The series of homoleptic lanthanide 1,2,3-triazolates (∞)(3)[Ln(Tz*)3] (Ln3+ = lanthanide cation, Tz*– = 1,2,3-triazolate anion, C2H2N3(–)) is completed by synthesis of the three-dimensional (3D) frameworks with Ln = La, Ce, Pr, Nd, and Sm, and characterization by X-ray powder diffraction, differential thermal analysis-thermogravimetry (DTA/TG) investigations and molecular vibration analysis. In addition, α-(∞)(2)[Sm(Tz*)3], a two-dimensional polymorph of 3D β-(∞)(3)[Sm(Tz*)3], is presented including the single crystal structure. The 3D lanthanide triazolates form an isotypic series of the formula (∞)(3)[Ln(Tz*)3] ranging from La to Lu, with the exception of Eu, which forms a mixed valent metal organic framework (MOF) of different structure and the constitution (∞)(3)[Eu(Tz*)(6+x)(Tz*H)(2–x)]. The main focus of this work is put on the investigation of the photoluminescence behavior of lanthanide 1,2,3-triazolates (∞)(3)[Ln(Tz*)3] and illuminates that six different luminescence phenomena can be found for one series of isotypic compounds. The luminescence behavior of the majority of these compounds is based on the photoluminescence properties of the organic linker molecules. Differing properties are observed for (∞)(3)[Yb(Tz*)3], which exhibits luminescence properties based on charge transfer transitions between the linker and Yb3+ ions, and for (∞)(3)[Ce(Tz*)3] and (∞)(3)[Tb(Tz*)3], in which the luminescence properties are a combination of the ligand and the lanthanide metal. In addition, strong inner-filter effects are found in the ligand emission bands that are attributed to reabsorption of the emitted light by the trivalent lanthanide ions. Antenna effects of varying efficiency are present indicated by the energy being transferred to the lanthanide ions subsequent to excitation of the ligand. (∞)(3)[Ce(Tz*)3] shows a 5d-4f induced intense blue emission upon excitation with UV light, while (∞)(3)[Tb(Tz*)3] shows emission in the green

  20. Genetic and proteomic characterization of rpoB mutations and their effect on nematicidal activity in Photorhabdus luminescens LN2.

    Directory of Open Access Journals (Sweden)

    Xuehong Qiu

    Full Text Available Rifampin resistant (Rif(R mutants of the insect pathogenic bacterium Photorhabdus luminescens LN2 from entomopathogenic nematode Heterorhabditis indica LN2 were genetically and proteomically characterized. The Rif(R mutants showed typical phase one characters of Photorhabdus bacteria, and insecticidal activity against Galleria mellonella larvae, but surprisingly influenced their nematicidal activity against axenic infective juveniles (IJs of H. bacteriophora H06, an incompatible nematode host. 13 out of 34 Rif(R mutants lost their nematicidal activity against H06 IJs but supported the reproduction of H06 nematodes. 7 nematicidal-producing and 7 non-nematicidal-producing Rif(R mutants were respectively selected for rpoB sequence analysis. rpoB mutations were found in all 14 Rif(R mutants. The rpoB (P564L mutation was found in all 7 mutants which produced nematicidal activity against H06 nematodes, but not in the mutants which supported H06 nematode production. Allelic exchange assays confirmed that the Rif-resistance and the impact on nematicidal activity of LN2 bacteria were conferred by rpoB mutation(s. The non-nematicidal-producing Rif(R mutant was unable to colonize in the intestines of H06 IJs, but able to colonize in the intestines of its indigenous LN2 IJs. Proteomic analysis revealed different protein expression between wild-type strain and Rif(R mutants, or between nematicidal-producing and non nematicidal-producing mutants. At least 7 putative proteins including DsbA, HlpA, RhlE, RplC, NamB (a protein from T3SS, and 2 hypothetical proteins (similar to unknown protein YgdH and YggE of Escherichia coli respectively were probably involved in the nematicidal activity of LN2 bacteria against H06 nematodes. This hypothesis was further confirmed by creating insertion-deletion mutants of three selected corresponding genes (the downregulated rhlE and namB, and upregulated dsbA. These results indicate that the rpoB mutations greatly influence the

  1. Synthesis, Characterization, Luminescence and Biological Activity of Two Lanthanide Complexes Involving Mixed Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Deyun; Guo, Haifu; Qin, Liang [Zhaoqing Univ., Zhaoqing (China); Xu, Jun [Jinan Univ., Guangzhou (China)

    2013-09-15

    Two new isostructural dinuclear complexes, Ln{sub 2}(4-cpa){sub 6}(bpy){sub 2} (Ln = Eu (1); Tb (2), 4-cpa = 4-chlorophenyl-acetate, bpy = 2,2'-bipyridine), have been hydrothermally synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction and single-crystal X-ray diffraction. The lanthanide ions are bridged by two bidentate and two terdentate carboxylate groups to give centrosymmetric dimers with Ln···Ln separations of 3.967(2) and 3.956(3) A, respectively. Each metal atom is nine-coordinate and exhibits a distorted tricapped trigonal prismatic geometry. Three-dimensional fluorescence spectra show that both 1 and 2 emit bright red and green luminescence at room temperature, with long lifetimes of up to 0.369 ms (at 614 nm) and 0.432 ms (at 543 nm), respectively. Moreover, poor luminescence efficiency has been noted for complex 2. The 4-Hcpa ligand and complexes 1-2 have been screened for their phytogrowth-inhibitory activities against Brassica napus L. and Echinochloa crusgalli L., and the results are compared with the activity of quizalofop-P-ethyl.

  2. On the Relevance of ln (z0 /z_{0T})= kB^{-1}

    Science.gov (United States)

    Hicks, Bruce B.; Pendergrass, William R.; Baker, Barry D.; Saylor, Rick D.; O'Dell, Debra L.; Eash, Neal S.; McQueen, Jeffrey T.

    2017-11-01

    The assumption that the roughness Reynolds number ( Re_{*}) can be used as a basis for quantifying the boundary-layer property { kB}^{-1} (= ln (z0/z_{0T})) as in some modern numerical models is questioned. While { Re}_{*} is a useful property in studies of pipe flow, it appears to have only marginal applicability in the case of treeless terrain, as studied in the two experimental situations presented here. For both the daytime and night-time cases there appears to be little correlation between { kB}^{-1} and { Re}_{*} . For daytime, the present studies indicate that the assumption { kB}^{-1} ≈ 2 is acceptable, while for night-time, the scatter involved in relating { kB}^{-1} to { Re}_{*} suggests there is little reason to assume a direct relationship. However, while the scatter affecting all of the night-time results is large, there remains a significant correlation between the heat and momentum fluxes upon which an alternative methodology for describing bulk air-surface exchange at night could be constructed. The friction coefficient (Cf ) and the turbulent Stanton number ({ St}_{*}) are discussed as possible alternatives for describing bulk properties of the air layer adjacent to the surface. While describing the surface roughness in terms of the friction coefficient provides an attractive simplification relative to the conventional methodologies based on roughness length and stability considerations, use of the Stanton number shares many of uncertainties that affect { kB}^{-1} . The transitions at dawn and dusk remain demanding situations to address.

  3. Influence of metal loading and humic acid functional groups on the complexation behavior of trivalent lanthanides analyzed by CE-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Kautenburger, Ralf, E-mail: r.kautenburger@mx.uni-saarland.de [Institute of Inorganic Solid State Chemistry, Saarland University, Campus Dudweiler, Am Markt Zeile 3-5, D-66125 Saarbrücken (Germany); Hein, Christina; Sander, Jonas M. [Institute of Inorganic Solid State Chemistry, Saarland University, Campus Dudweiler, Am Markt Zeile 3-5, D-66125 Saarbrücken (Germany); Beck, Horst P. [Institute of Inorganic and Analytical Chemistry and Radiochemistry, Saarland University, Campus Dudweiler, Am Markt Zeile 5, D-66125 Saarbrücken (Germany)

    2014-03-01

    Highlights: • Free and complexed HA-Ln species are separated by CE-ICP-MS. • Weaker and stronger HA-binding sites for Ln-complexation can be detected. • Complexation by original and modified humic acid (HA) with blocked phenolic hydroxyl- and carboxyl-groups is compared. • Stronger HA-binding sites for Ln³⁺ can be assumed as chelating complexes. • Chelates consist of trivalent Ln and a combination of both OH- and COOH-groups. Abstract: The complexation behavior of Aldrich humic acid (AHA) and a modified humic acid (AHA-PB) with blocked phenolic hydroxyl groups for trivalent lanthanides (Ln) is compared, and their influence on the mobility of Ln(III) in an aquifer is analyzed. As speciation technique, capillary electrophoresis (CE) was hyphenated with inductively coupled plasma mass spectrometry (ICP-MS). For metal loading experiments 25 mg L⁻¹ of AHA and different concentrations (c Ln(Eu+Gd)} = 100–6000 μg L⁻¹) of Eu(III) and Gd(III) in 10 mM NaClO₄ at pH 5 were applied. By CE-ICP-MS, three Ln-fractions, assumed to be uncomplexed, weakly and strongly AHA-complexed metal can be detected. For the used Ln/AHA-ratios conservative complex stability constants log βLnAHA decrease from 6.33 (100 μg L⁻¹ Ln³⁺) to 4.31 (6000 μg L⁻¹ Ln³⁺) with growing Ln-content. In order to verify the postulated weaker and stronger humic acid binding sites for trivalent Eu and Gd, a modified AHA with blocked functional groups was used. For these experiments 500 μg L⁻¹ Eu and 25 mg L⁻¹ AHA and AHA-PB in 10 mM NaClO₄ at pH-values ranging from 3 to 10 have been applied. With AHA-PB, where 84% of the phenolic OH-groups and 40% of the COOH-groups were blocked, Eu complexation was significantly lower, especially at the strong binding sites. The log β-values decrease from 6.11 (pH 10) to 5.61 at pH 3 (AHA) and for AHA-PB from 6.01 (pH 7) to 3.94 at pH 3. As a potential consequence, particularly humic acids with a high amount of

  4. Synthesis, structures, and luminescent properties of sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4} (Ln = Sm, Eu, Gd, Tb, Dy, and Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Charkin, Dmitri O.; Dorofeev, Sergey G.; Berdonosov, Peter S.; Dolgikh, Valery A. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Zitzer, Sabine; Greiner, Stefan; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Olenev, Andrei V. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Sine Theta Ltd., Moscow (Russian Federation)

    2017-11-17

    Six sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, isostructural to Na{sub 2}Y{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, were synthesized by flux techniques and characterized by single-crystal XRD. The compounds crystallize in the monoclinic space group C2/c with lattice constants a = 23.967(1), b = 5.6342(3), c = 16.952(1) Aa, β = 134.456(5) for Ln = Sm, a = 23.932(2), b = 5.6044(5), c = 17.134(1) Aa, β = 135.151(6) for Ln = Eu, a = 23.928(1), b = 5.5928(1), c = 17.1133(8) Aa, β = 135.366(3) for Ln = Gd, a = 23.907(1), b = 5.569(3), c = 16.745(1) Aa, β = 134.205(3) for Ln = Tb, a = 23.870(1), b = 5.547(3), c = 16.665(1) Aa, β = 134.102(3) for Ln = Dy, and a = 23.814(1), b = 5.526(3), c = 16.626(1) Aa, β = 134.016(3) for Ln = Ho and Z = 4. Their crystal structure can be considered as a framework built of intergrowing Ln-O and Na-(O,Cl) slabs with channel walls decorated by tellurium atoms of [TeO{sub 3}]{sup 2-} groups. The luminescent properties of the new compounds due to the Ln{sup 3+} cations are described and discussed. We also discuss the crystal chemistry of various alkali-metal rare-earth metal(III) halide oxochalcogenates(IV). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Evidence of different stoichiometries for the limiting carbonate complexes of lanthanides(3); Mise en evidence d'un changement de stoechiometrie du complexe carbonate limite au sein de la serie des lanthanides(3)

    Energy Technology Data Exchange (ETDEWEB)

    Philippini, V

    2007-12-15

    Two stoichiometries have been proposed by different laboratories to interpret measurements on the limiting carbonate complexes of An{sup 3+} and Ln{sup 3+} cations. The study of the solubility of double carbonates (AlkLn(CO{sub 3}){sub 2},xH{sub 2}O) in concentrated carbonate solutions at room temperature and high ionic strengths has shown that on the one hand the lightest lanthanides (La and Nd) form Ln(CO{sub 3}){sub 4}{sup 5-} whereas the heaviest (Eu and Dy) form Ln(CO{sub 3}){sub 3}{sup 3-} in the studied chemical conditions, and on the other hand, that the kinetics of precipitation of double carbonates depends on the alkali metal and the lanthanide ions. The existence of two stoichiometries for the limiting carbonate complexes was confirmed by capillary electrophoresis hyphenated to an inductively coupled plasma mass spectrometer (CE-ICP-MS), used to extend the study to the whole series of lanthanides (except Ce, Pm and Yb). Two behaviours have been put forward comparing the electrophoretic mobilities: La to Tb form Ln(CO{sub 3}){sub 4}{sup 5-} while Dy to Lu form Ln(CO{sub 3}){sub 3}{sup 3-}. Measurements by time resolved laser fluorescence spectroscopy (TRLFS) on Eu(III) indicate small variations of the geometry of Eu(CO{sub 3}){sub 3}{sup 3-} complex, specially with Cs{sup +}. Although analogies are currently used among the 4f-block trivalent elements, different aqueous speciations are evidenced in concentrated carbonate solutions across the lanthanide series. (author)

  6. A deadly organometallic luminescent probe: anticancer activity of a ReI bisquinoline complex.

    Science.gov (United States)

    Kitanovic, Igor; Can, Suzan; Alborzinia, Hamed; Kitanovic, Ana; Pierroz, Vanessa; Leonidova, Anna; Pinto, Antonio; Spingler, Bernhard; Ferrari, Stefano; Molteni, Roberto; Steffen, Andreas; Metzler-Nolte, Nils; Wölfl, Stefan; Gasser, Gilles

    2014-02-24

    The photophysical properties of [Re(CO)3 (L-N3)]Br (L-N3 =2-azido-N,N-bis[(quinolin-2-yl)methyl]ethanamine), which could not be localized in cancer cells by fluorescence microscopy, have been revisited in order to evaluate its use as a luminescent probe in a biological environment. The Re(I) complex displays concentration-dependent residual fluorescence besides the expected phosphorescence, and the nature of the emitting excited states have been evaluated by DFT and time-dependent (TD) DFT methods. The results show that fluorescence occurs from a (1) LC/MLCT state, whereas phosphorescence mainly stems from a (3) LC state, in contrast to previous assignments. We found that our luminescent probe, [Re(CO)3 (L-N3)]Br, exhibits an interesting cytotoxic activity in the low micromolar range in various cancer cell lines. Several biochemical assays were performed to unveil the cytotoxic mechanism of the organometallic Re(I) bisquinoline complex. [Re(CO)3 (L-N3)]Br was found to be stable in human plasma indicating that [Re(CO)3 (L-N3)]Br itself and not a decomposition product is responsible for the observed cytotoxicity. Addition of [Re(CO)3 (L-N3)]Br to MCF-7 breast cancer cells grown on a biosensor chip micro-bioreactor immediately led to reduced cellular respiration and increased glycolysis, indicating a large shift in cellular metabolism and inhibition of mitochondrial activity. Further analysis of respiration of isolated mitochondria clearly showed that mitochondrial respiratory activity was a direct target of [Re(CO)3 (L-N3)]Br and involved two modes of action, namely increased respiration at lower concentrations, potentially through increased proton transport through the inner mitochondrial membrane, and efficient blocking of respiration at higher concentrations. Thus, we believe that the direct targeting of mitochondria in cells by [Re(CO)3 (L-N3)]Br is responsible for the anticancer activity. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Synthesis and preliminary structural characterization of some lanthanide(III semicarbazone complex

    Directory of Open Access Journals (Sweden)

    Ram K. Agarwal

    2006-06-01

    Full Text Available Some six and nine coordinated complexes of trivalent lanthanide metal ions with 4[N-(2'-hydroxy-1'-naphthalideneamino]antipyrinesemicarbazone (HNAAPS with the general composition LnX3.n(HNAAPS [X = NO3, n = 1; X = NCS or ClO4, n = 2; Ln = La, Pr, Nd, Sm, Gd, Tb, Dy or Ho] have been isolated. All the complexes have been characterized on the basis of analytical data, molar conductance, magnetic susceptibility, electronic and infrared spectral measurements. The ligand HNAAPS behaves as neutral tridentate (N, N, O ligand. The coordination number of the central metal ion is either six or nine in these complexes. Thermal properties of these complexes were also investigated.

  8. Photoluminescent materials based on silica doped with lanthanide complexes of 4'-formylbenzo-15-crown-5.

    Science.gov (United States)

    Soares-Santos, Paula C R; Ferreira, Rute A S; Trindade, Tito; Carlos, Luís D; Nogueira, Helena I S

    2010-04-01

    Photoluminescent materials were prepared by introducing lanthanide complexes of 4'-formylbenzo-15-crown-5 (C15H20O6) into a silica matrix obtained by the sol-gel method. The new lanthanide complexes [Ln(C15H20O6)(NO3)3(H2O)2] (Ln3+ = Sm3+, Eu3+ and Tb3+) were synthesized and were fully characterised using spectroscopic techniques, and elemental and thermogravimetric analysis. Photoluminescence measurements were performed for the isolated Eu3+ and Tb3+ complexes as well as for their related silica based materials. A detailed comparative analysis on the photoluminescent properties of the EU3+ complex and of its derived silica material was carried out.

  9. A disymmetric terpyridine based ligand for the formation of luminescent di-aquo lanthanide complexes.

    Science.gov (United States)

    Charbonnière, Loïc J; Mameri, Samir; Flot, David; Waltz, Fanny; Zandanel, Christelle; Ziessel, Raymond F

    2007-06-14

    The synthesis of ligand H3 based on a disymmetrically substituted terpyridine core functionalised by a carboxylic acid in the 6-position and a bis(carboxymethyl)aminomethyl function in the 6''-position is described. The coordination behaviour of this heptadentate (4N/3O) ligand with lanthanide cations (Ln=Eu, Gd and Tb) was studied in solution showing the formation of complexes with [Ln] stoichiometry. Complexes with general formula [Ln(H2O)2] were isolated from neutral water solutions containing equimolar amounts of cations and ligands, and the complexes were characterized in the solid state (elemental analysis, IR) and in solution (mass spectrometry). The photo-physical properties of the luminescent complexes of Eu and Tb were studied in water solution by means of absorption, steady state and time-resolved emission spectroscopies. Evolution of the luminescence lifetimes of the Eu and Tb complexes in H2O and D2O reveals the presence of two water molecules coordinated in the first coordination sphere of the cations. Despite this important hydration number, the overall luminescence quantum yields of the complexes remained elevated, especially in the case of Tb (Phi=22.0 and 6.5% respectively for Tb and Eu). Upon crystallisation the Gd complex formed dimeric species in which two gadolinium atoms are each heptacoordinated by one ligand, the coordination sphere being completed by a single water molecule and a bridging carboxylate function, pointing to different behaviours in the solid and liquid states.

  10. Luminescent pillared Ln{sup III}–Zn{sup II} heterometallic coordination frameworks with two kinds of N-heterocyclic carboxylate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Sui-Jun; Jia, Ji-Min; Cui, Yu; Han, Song-De; Chang, Ze, E-mail: changze@nankai.edu.cn

    2014-04-01

    In our efforts toward rational design and systematic synthesis of ‘pillar-layer’ structure coordination frameworks, four new Ln{sup III}–Zn{sup II} heterometallic coordination polymers (CPs) based on two kinds of N-heterocyclic carboxylic ligands with formula ([LnZn(L1){sub 2}(L2)(H{sub 2}O){sub m}]·nH{sub 2}O){sub ∞} (Ln=La (1), Eu (2), Gd (3) and Dy (4), m=3 (for 1) and 2 (for 2–4), n=8 (for 1) and 7 (for 2–4), H{sub 2}L1=pyridine-2,3-dicarboxylate acid, HL2=isonicotinic acid), have been synthesized under hydrothermal reaction of Ln{sub 2}O{sub 3}, ZnO, H{sub 2}L1 and HL2. CP 1 has a three-dimensional (3D) structure with a (3,6)-connected sit topology network, while CPs 2–4 are isostructural with 3D single-node pcu alpha-Po topology network. Also, luminescent properties of these CPs have also been investigated. The emission of 1 and 3 should be attributed to the coordination-perturbed ligand-centered luminescence and the emission spectra of 2 and 4 show the characteristic bands of the corresponding Ln{sup III} ions. - Graphical abstract: Four new 3D Ln{sup III}–Zn{sup II} coordination frameworks with “pillar-layer” sit or pcu alpha-Po topology have been successfully obtained. Moreover, the photoluminescent properties of compounds 1–4 have also been investigated. - Highlights: • Four new Ln{sup III}–Zn{sup II} heterometallic coordination frameworks with two types of topologies have been synthesized. • Metal oxides and two kinds of N-heterocyclic carboxylate ligands were used for the construction of targeted coordination polymers. • The luminescent properties of the coordination polymers are investigated.

  11. Spectroscopic studies of some lanthanide(III nitrate complexes synthesized from a new ligand 2,6-bis-(salicylaldehyde hydrazone-4-chlorophenol

    Directory of Open Access Journals (Sweden)

    A.S. Sall

    2003-06-01

    Full Text Available The ligand 2,6-bis-(salicylaldehydehydrazone-4-chlorophenol (H5L and its binuclear lanthanide(III nitrate complexes {[Ln2(H4L3(NO3](NO32.mH2O} where Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb and Y, have been synthesized. The complexes were characterized by chemical analysis, conductance, magnetic moment measurements and infrared spectra. Infrared study indicates that the ligand behaves both as neutral and ionic O donors and as neutral N donors.

  12. Entropy and complexity analysis of hydrogenic Rydberg atoms

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rosa, S. [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain); Departamento de Fisica Aplicada II, Universidad de Sevilla, 41012-Sevilla (Spain); Toranzo, I. V.; Dehesa, J. S. [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, 18071-Granada (Spain); Sanchez-Moreno, P. [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain); Departamento de Matematica Aplicada, Universidad de Granada, 18071-Granada (Spain)

    2013-05-15

    The internal disorder of hydrogenic Rydberg atoms as contained in their position and momentum probability densities is examined by means of the following information-theoretic spreading quantities: the radial and logarithmic expectation values, the Shannon entropy, and the Fisher information. As well, the complexity measures of Cramer-Rao, Fisher-Shannon, and Lopez Ruiz-Mancini-Calvet types are investigated in both reciprocal spaces. The leading term of these quantities is rigorously calculated by use of the asymptotic properties of the concomitant entropic functionals of the Laguerre and Gegenbauer orthogonal polynomials which control the wavefunctions of the Rydberg states in both position and momentum spaces. The associated generalized Heisenberg-like, logarithmic and entropic uncertainty relations are also given. Finally, application to linear (l= 0), circular (l=n- 1), and quasicircular (l=n- 2) states is explicitly done.

  13. [Ru(III)(valen)(CN)2](-): a New Building Block To Design 4d-4f Heterometallic Complexes.

    Science.gov (United States)

    Marinescu, Gabriela; Maxim, Catalin; Clérac, Rodolphe; Andruh, Marius

    2015-06-15

    New 4d-4f heterometallic complexes with a one-dimensional structure, (1)∞[{Ru(valen)(CN)2KRu(valen)(CN)2}{Ln(O2NO)2(CH3OH)3}]·2CH3OH (Ln = Gd, Tb, Dy), have been assembled from the reaction of [K(H2O)2Ru(III)(valen)(CN)2]·H2O with lanthanide nitrates. The exchange interaction between Ru(III) and Gd(III) mediated by the cyanido ligand was determined for the first time and found to be weak and of antiferromagnetic nature.

  14. Lanthanide-organic complexes based on polyoxometalates: Solvent effect on the luminescence properties

    Science.gov (United States)

    Tang, Qun; Liu, Shu-Xia; Liang, Da-Dong; Ma, Feng-Ji; Ren, Guo-Jian; Wei, Feng; Yang, Yuan; Li, Cong-Cong

    2012-06-01

    A series of lanthanide-organic complexes based on polyoxometalates (POMs) [Ln2(DNBA)4(DMF)8][W6O19] (Ln=La(1), Ce(2), Sm(3), Eu(4), Gd(5); DNBA=3,5-dinitrobenzoate; DMF=N,N-dimethylformamide) has been synthesized. These complexes consist of [W6O19]2- and dimeric [Ln2(DNBA)4(DMF)8]2+ cations. The luminescence properties of 4 are measured in solid state and different solutions, respectively. Notably, the emission intensity increases gradually with the increase of solvent permittivity, and this solvent effect can be directly observed by electrospray mass spectrometry (ESI-MS). The analyses of ESI-MS show that the eight coordinated solvent DMF units of dimeric cation are active. They can move away from dimeric cations and exchange with solvent molecules. Although the POM anions escape from 3D supramolecular network, the dimeric state structure of [Ln2(DNBA)4]2+ remains unchanged in solution. The conservation of red luminescence is attributed to the maintenance of the aggregated state structures of dimeric cations.

  15. Alpha Radiolysis of Nuclear Solvent Extraction Ligands Used for An(III) and Ln(III) Separations

    Energy Technology Data Exchange (ETDEWEB)

    Mezyk, Stephen P. [California State Univ. (CalState), Long Beach, CA (United States); Mincher, Bruce J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nilsson, Mikael [Univ. of California, Irvine, CA (United States)

    2016-08-01

    This document is the final report for the Nuclear Energy Universities Program (NEUP) grant 10-910 (DE-AC07-05ID14517) “Alpha Radiolysis of Nuclear Solvent Extraction Ligands used for An(III) and Ln(III) Separations”. The goal of this work was to obtain a quantitative understanding of the impacts of both low Linear Energy Transfer (LET, gamma-rays) and high LET (alpha particles) radiation chemistry occurring in future large-scale separations processes. This quantitative understanding of the major radiation effects on diluents and ligands is essential for optimal process implementation, and could result in significant cost savings in the future.

  16. Effect of principal and secondary ligands on the electronic structures and spectra of a series of ruthenium(II complexes

    Directory of Open Access Journals (Sweden)

    Zhang Yanli

    2016-01-01

    Full Text Available A DFT(density functional theory/TDDFT(time-dependent density functional theory investigation is performed to study the ground-state geometries, electronic structures, and absorption spectra of twelve ruthenium(II thiosemicarbazone complexes [Ru(CO(C(Ln], where Ln=derivatives of dibasic tetradentate Schiff-base ligand and X=AsPh3/PPh3/Py. The ground-state geometries are optimized at the B3LYP/6-31G(d-LANL2DZ level, and the spectra are simulated by means of TD-B3LYP/6-31G(d-LANL2DZ method on the basis of the optimized geometries. The influence of principal and secondary ligands (Ln and X on transition characters and absorption peak positions is evaluated.

  17. Electronic phase separation in the rare-earth manganates (La sub 1 sub - sub x Ln sub x) sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 3 (Ln = Nd, Gd and Y)

    CERN Document Server

    Sudheendra, L

    2003-01-01

    Electron transport and magnetic properties of three series of manganates of the formula (La sub 1 sub - sub x Ln sub x) sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 3 with Ln = Nd, Gd and Y, wherein only the average A-site cation radius (r sub A ) and associated disorder vary, without affecting the Mn sup 4 sup + /Mn sup 3 sup + ratio, have been investigated in an effort to understand the nature of phase separation. All three series of manganates show saturation magnetization characteristic of ferromagnetism, with the ferromagnetic T sub c decreasing with increasing x up to a critical value of x, x sub c (x sub c = 0.6, 0.3, 0.2 respectively for Nd, Gd, Y). For x > x sub c , the magnetic moments are considerably smaller, showing a small increase around T sub M , the value of T sub M decreasing slightly with increase in x or decrease in (r sub A ). The ferromagnetic compositions (x x sub c are insulating. The magnetic and electrical resistivity behaviour of these manganates is consistent with the occurrence...

  18. Near-infrared photoluminescence in La{sub 0.98}AlO{sub 3}: {sub 0.02}Ln{sup 3+}(Ln = Nd/Yb) for sensitization of c-Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sawala, N. S., E-mail: nssawala@gmail.com; Koparkar, K. A.; Omanwar, S. K. [Department of Physics, SantGadge Baba Amravati University, Amravati - MH, 444602 (India); Bajaj, N. S. [Department of Physics, Toshniwal Art, Commerce and Science College, Sengoan, Hingoli - MH (India)

    2016-05-06

    The host matrix LaAlO{sub 3} was synthesized by conventional solid state reaction method in which the Nd{sup 3+} ions and Yb{sup 3+} ions successfully doped at 2mol% concentrations. The phase purity was confirmed by X ray powder diffraction (XRD) method. The photoluminescence (PL) properties were studied by spectrophotometer in near infra red (NIR) and ultra violet visible (UV-VIS) region. The Nd{sup 3+} ion doped LaAlO{sub 3} converts a visible (VIS) green photon (587 nm) into near infrared (NIR) photon (1070 nm) while Yb{sup 3+} ion doped converts ultra violet (UV) photon (221 nm) into NIR photon (980 nm). The La{sub 0.98}AlO{sub 3}: {sub 0.02}Ln{sup 3+}(Ln = Nd / Yb) can be potentiality used for betterment of photovoltaic (PV) technology. This result further indicates its potential application as a luminescence converter layer for enhancing solar cells performance.

  19. Low-temperature coprecipitation synthesis and luminescent properties of LaPO(4):Ln(3+) (Ln(3+) = Ce(3+), Tb(3+)) nanowires and LaPO(4):Ce(3+),Tb(3+)/LaPO(4) core/shell nanowires.

    Science.gov (United States)

    Yang, Mei; You, Hongpeng; Liu, Kai; Zheng, Yuhua; Guo, Ning; Zhang, Hongjie

    2010-06-07

    LaPO(4):Ln(3+) (Ln(3+)= Ce(3+), Tb(3+)) and LaPO(4):Ce(3+),Tb(3+)/LaPO(4) core/shell nanowires have been synthesized on a large scale through a direct precipitation in a water-based system under moderate conditions without the assistance of any surfactant, catalyst, or template. The diameters of the obtained nanowires are about 15 nm, and the lengths range from a few hundred nanometers to several micrometers. The influences of the solution acidity, reaction time, and proportion of ethanol to water on the final products were investigated in detail. It was found that the lengths of nanowires can be efficiently controlled by adjusting the reaction conditions. The formation mechanism of the products is proposed on the basis of time-dependent experiments as well as the crystal structure of the products. The luminescent properties of the products were also studied. A LaPO(4) shell on the LaPO(4):Ce(3+),Tb(3+) nanowires can greatly increase the intensity of the product, and the thickness of the shell also has an important effect on the intensity of the product. The method is a novel and facile route for the synthesis of one-dimensional lanthanide phosphates.

  20. Grain and grain boundary transport in BaCe0.5Zr0.3Ln0.2O3-δ (Ln - Y or lanthanide) electrolytes attractive for protonic ceramic fuel cells application

    Science.gov (United States)

    Danilov, N.; Pikalova, E.; Lyagaeva, J.; Antonov, B.; Medvedev, D.; Demin, A.; Tsiakaras, P.

    2017-10-01

    Protonic ceramic fuel cells (PCFCs) belong to very attractive energy conversion systems, which are able to operate effectively at low- and intermediate temperature ranges. The improvement of their electrochemical characteristics is feasible through the optimization of their functional materials. In the present work, emphasis is given to the highly conductive and stable cerate-zirconate electrolytes of BaCe0.5Zr0.3Ln0.2O3-δ (where Ln = Y, Dy, Sm and Nd). Studying the transport properties of these materials in individual form and in PCFC assembly, it is shown that the Dy-doped sample exhibits higher grain (bulk) and grain boundary conductivity in comparison with the most studied Y-doped ones. The single PCFC based on a rather thick 30 μm electrolyte displays about 160 and 290 mW cm-2 at 600 and 700 °C, respectively. These values are comparative with those obtained for PCFCs fabricated with similar electrolytes and Co-free cathode materials, confirming the perspective of cerate-zirconates doped by other lanthanides.

  1. Syntheses, structure and properties of three-dimensional pillared-layer Ag(I)-Ln(III) heterometallic coordination polymers based on mixed isonicotinate and hemimellitate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xinfa, E-mail: xflichem@163.com [Department of Chemistry, Zunyi Normal College, Zunyi 563002 (China); Cao, Rong, E-mail: rcao@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)

    2012-12-15

    Three pillared-layer 4d-4f Ag(I)-Ln(III) heterometallic coordination polymers (HCPs), formulated as [Ln{sub 2}Ag(hma){sub 2}(ina)(H{sub 2}O){sub 2}]{sub n} nH{sub 2}O [Ln=La(1), Pr(2), Nd(3); Hina=isonicotinic acid, H{sub 3}hma=hemimellitic acid], have been synthesized under hydrothermal conditions. Single-crystal and powder X-ray diffractions confirm that they are isostructural, which features a three-dimensional (3D) pillared-layer heterometallic structure built upon the strictly alternate arrangement of lanthanide-organic layers and [Ag(ina)] pillars. The layers and pillars are connected to each other by Ln-O and Ag-O coordination bonds. The photoluminescent property of the Nd derivative (3) has also been investigated. - Graphical abstract: Three pillared-layer 4d-4f Ag(I)-Ln(III) heterometallic coordination polymers have been synthesized and structurally characterized. Highlights: Black-Right-Pointing-Pointer Three 3D pillared-layer 4d-4f HCPs were synthesized by hydrothermal reactions. Black-Right-Pointing-Pointer The synergistic coordination strategy was employed. Black-Right-Pointing-Pointer It opens new perspective for the construction of structurally diversified 4d-4f HCPs.

  2. Complexation of trivalent americium and lanthanides with terdentate 'N' donor ligands: the role of rigidity in the ligand structure.

    Science.gov (United States)

    Bhattacharyya, Arunasis; Gadly, Trilochan; Pathak, Priyanath; Ghosh, Sunil K; Mohapatra, Manoj; Ghanty, Tapan K; Mohapatra, Prasanta K

    2014-08-28

    A systematic study on the Ln(3+) complexation behaviour with two terdentate 'N' donor ligands of varying structural rigidity, viz. 5,6-dimethyl-(1,2,4)-triazinylbipyridine (Me2TBipy) and 5,6-dimethyl-(1,2,4)-triazinylphenanthroline (Me2TPhen), is performed in the present work by UV-Vis spectrophotometry, time resolved fluorescence spectroscopy (TRFS) and electrospray ionization mass spectrometric (ESI-MS) studies. These studies indicate the formation of a 1 : 1 complex of La(3+), 1 : 2 complexes of Eu(3+) and Er(3+) with both the ligands. Density functional theoretical (DFT) study is carried out to determine the solution phase structure of the Eu(3+) complex considering the species (from UV-Vis spectrophotometry) and C2v site symmetry around the Eu(3+) ion (from TRFS study). Me2TPhen is found to be a stronger complexing ligand as compared to Me2TBipy irrespective of the Ln(3+) ions. The solid state crystal structure of the La(3+) complex of Me2TPhen is determined using the single crystal X-ray diffraction (SCXRD) technique. The complexation of the trivalent Am(3+) ion is also studied with both these ligands using UV-Vis spectrophotometric titrations which show the formation of 1 : 2 complexes with higher complexation constant values as compared to all the Ln(3+) ions studied, indicating the selectivity of these ligands for the trivalent actinides over the lanthanides.

  3. Chemical and structural changes in Ln{sub 2}NiO{sub 4+δ} (Ln=La, Pr or Nd) lanthanide nickelates as a function of oxygen partial pressure at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Flura, Aurélien; Dru, Sophie; Nicollet, Clément; Vibhu, Vaibhav; Fourcade, Sébastien; Lebraud, Eric; Rougier, Aline; Bassat, Jean-Marc; Grenier, Jean-Claude, E-mail: grenier@icmcb-bordeaux.cnrs.fr

    2015-08-15

    The chemical stability of lanthanide nickelates Ln{sub 2}NiO{sub 4+δ} (Ln=La, Pr or Nd) has been studied in the temperature range 25–1300 °C, either in air or at low pO{sub 2} (down to 10{sup −4} atm). Thermal gravimetry analysis (TGA) measurements coupled with X-ray diffraction (XRD) characterization have shown that all compounds retain their K{sub 2}NiF{sub 4}-type structure in these conditions, while remaining over-stoichiometric in oxygen up to 1000 °C. Only Nd{sub 2}NiO{sub 4+δ} starts to decompose into Nd{sub 2}O{sub 3} and NiO above 1000 °C, at pO{sub 2}=10{sup −4} atm. In addition, a careful analysis of the lanthanide nickelates structural features has been performed by in situ XRD, as a function of temperature and pO{sub 2}. For all compounds, a structural transition has been always observed in the temperature range 200–400 °C, in air or at pO{sub 2}=10{sup −4} atm. In addition, their cell volume did not vary upon the variation of the oxygen partial pressure. Therefore, these materials do not exhibit a chemical expansion in these conditions, which is beneficial for a fuel cell application as cathode layers. Additional dilatometry measurements have revealed that a temperature as high as 950 °C for Pr{sub 2}NiO{sub 4+δ} or 1100 °C for La{sub 2}NiO{sub 4+δ} and Nd{sub 2}NiO{sub 4+δ} has to be reached in order to begin the sintering of the material particles, which is of primary importance to obtain an efficient electronic/ionic conduction in the corresponding designed cathode layers. Besides, excellent matching was found between the thermal expansion coefficients of lanthanide nickelates and SOFC electrolytes such as 8wt% yttria stabilized zirconia (8YSZ) or Ce{sub 0.8}Gd{sub 0.2}O{sub 2−δ} (GDC), at least from 400 °C up to 1400 °C in air or up to 1200 °C at pO{sub 2}=10{sup −4} atm. - Graphical abstract: This study reports the good chemical stability of oxygen overstoichiometric Ln2NiO4+δ(Ln = La, Pr or Nd) at high temperatures

  4. Solid-state and solution-state coordination chemistry of lanthanide(III) complexes with (pyrazol-1-yl)acetic acid.

    Science.gov (United States)

    Chen, Xiao-Yan; Goff, George S; Scott, Brian L; Janicke, Michael T; Runde, Wolfgang

    2013-03-18

    As a precursor of carboxyl-functionalized task-specific ionic liquids (TSILs) for f-element separations, (pyrazol-1-yl)acetic acid (L) can be deprotonated as a functionalized pyrazolate anion to coordinate with hard metal cations. However, the coordination chemistry of L with f-elements remains unexplored. We reacted L with lanthanides in aqueous solution at pH = 5 and synthesized four lanthanide complexes of general formula [Ln(L)3(H2O)2]·nH2O (1, Ln = La, n = 2; 2, Ln = Ce, n = 2; 3, Ln = Pr, n = 2; 4, Ln = Nd, n = 1). All complexes were characterized by single crystal X-ray diffraction analysis revealing one-dimensional chain formations. Two distinct crystallographic structures are governed by the different coordination modes of carboxylate groups in L: terminal bidentate and bridging tridentate (1-3); terminal bidentate, bridging bidentate, and tridentate coordination in 4. Comparison of the solid state UV-vis-NIR diffuse reflectance spectra with solution state UV-vis-NIR spectra suggests a different species in solution and solid state. The different coordination in solid state and solution was verified by distinctive (13)C NMR signals of the carboxylate groups in the solid state NMR.

  5. Analytic amplitudes for hadronic forward scattering and the Heisenberg ln{sup 2} s behaviour of total cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Nicolescu, Basarab [LPNHE, Unite de Recherche des Universites Paris 6 et Paris 7, associee au CNRS, Theory Group, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2004-07-01

    We consider several classes of analytic parametrizations of hadronic scattering amplitudes (the COMPETE analysis), and compare their predictions to all available forward data (pp, {pi}p, Kp, {gamma}p, {gamma}{gamma}, {sigma}p). Although these parametrizations are very close for {radical}s {>=} 9 GeV, it turns out that they differ markedly at low energy, where a universal Pomeron term {approx} ln{sup 2} s enables one to extend the fit down to {radical}s = 4 GeV. We present predictions on the total cross sections and on the ratio of the real part to the imaginary part of the elastic amplitude ({rho} parameter) for present and future pp colliders, and on total cross sections for {gamma}p {yields} hadrons at cosmic-ray energies and for it{gamma}{gamma} {yields} hadrons up to {radical}s = 1 TeV. The ln{sup 2} s behaviour of total cross sections, first obtained by Heisenberg 50 years ago, receives now increased interest both on phenomenological and theoretical levels. We present a modification of the Heisenberg's model in connection with the presence of glueballs and we show that it leads to a realistic description of all existing hadron total cross-sections data, in agreement with the COMPETE analysis.

  6. Řízení robotické ruky pomocí virtuální reality

    OpenAIRE

    Sláma, Pavel

    2017-01-01

    Tato bakalářská práce se zabývá možností řešení řízení robotické ruky pomocí virtuální reality. K realizaci je využita protetická ruka z projektu InMoov. Práce popisuje základní výrobní principy 3D tisku a zabývá se materiály vhodnými pro konstrukci zvolené robotické ruky. Popisuje funkci a způsob řízení servomotorů, ovládání za využití platformy Arduino komunikující s počítačem za softwarové podpory prostředí MyRobotLab. Pro snímání pohybu je použit ovladač pro virtuální realitu Leap Motion....

  7. Synthesis of Multicolor Core/Shell NaLuF₄:Yb(3+)/Ln(3+)@CaF₂ Upconversion Nanocrystals.

    Science.gov (United States)

    Li, Hui; Hao, Shuwei; Yang, Chunhui; Chen, Guanying

    2017-02-07

    The ability to synthesize high-quality hierarchical core/shell nanocrystals from an efficient host lattice is important to realize efficacious photon upconversion for applications ranging from bioimaging to solar cells. Here, we describe a strategy to fabricate multicolor core @ shell α-NaLuF₄:Yb(3+)/Ln(3+)@CaF₂ (Ln = Er, Ho, Tm) upconversion nanocrystals (UCNCs) based on the newly established host lattice of sodium lutetium fluoride (NaLuF₄). We exploited the liquid-solid-solution method to synthesize the NaLuF₄ core of pure cubic phase and the thermal decomposition approach to expitaxially grow the calcium fluoride (CaF₂) shell onto the core UCNCs, yielding cubic core/shell nanocrystals with a size of 15.6 ± 1.2 nm (the core ~9 ± 0.9 nm, the shell ~3.3 ± 0.3 nm). We showed that those core/shell UCNCs could emit activator-defined multicolor emissions up to about 772 times more efficient than the core nanocrystals due to effective suppression of surface-related quenching effects. Our results provide a new paradigm on heterogeneous core/shell structure for enhanced multicolor upconversion photoluminescence from colloidal nanocrystals.

  8. Heteropentanuclear Oxalato-Bridged nd–4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity

    KAUST Repository

    Kuhn, Paul-Steffen

    2015-08-10

    A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d–4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by 13C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)]2− are coordinated to YIII and DyIII, respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4]5− (Ln=Y, Dy). While YIII is eight-coordinate in 2, DyIII is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N+ ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2–5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d–4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2–5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d–4f metal complexes 6–9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells.

  9. Steric effect involved in Ln3+/Ce3+ exchange in a coordination polymer based on di(2-ethylhexyl)phosphoric acid.

    Science.gov (United States)

    Tasaki-Handa, Yuiko; Abe, Yukie; Ooi, Kenta; Tanaka, Mikiya; Wakisaka, Akihiro

    2014-01-28

    Coordination polymers can be attractive ion exchange materials because of their crystallinity and semi-flexibility, which are rather opposing properties, and play integral and synergistic roles in introducing unique ion-exchange behavior. In this paper, Ln(3+)/Ce(3+) exchange (Ln(3+) = Nd(3+), Gd(3+), Dy(3+), or Lu(3+)) in a coordination polymer, [Ce(dehp)3], based on di(2-ethylhexyl)phosphoric acid (Hdehp) is studied by distribution coefficient measurements, ion-exchange isotherms, Kielland plot analysis, and morphology observation. The ion-exchange selectivity is in the order Nd(3+) dissolution-recrystallization. The small steric strain in the Nd(3+)/Ce(3+) system leads to the formation of a Nd(3+)-and-Ce(3+) solid-solution, whereas the morphological change is possibly restrained by the strong strain caused by loaded Ln(3+) with an ionic size significantly smaller than the original Ce(3+).

  10. Detection of bacterial spores with lanthanide-macrocycle binary complexes.

    Science.gov (United States)

    Cable, Morgan L; Kirby, James P; Levine, Dana J; Manary, Micah J; Gray, Harry B; Ponce, Adrian

    2009-07-15

    The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide-macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)(+) binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb(3+) alone, and 10-fold greater than other Ln(DO2A)(+) complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb-DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)(+), yielding a 3-fold increase in the signal-to-noise ratio over Tb(3+). Out of the eight cases investigated, the Tb(DO2A)(+) binary complex is best for the detection of bacterial spores.

  11. Structural and spectroscopic investigation of new luminescent hybrid materials based on calix[4]arene-tetracarboxylate and Ln3+ ions (Ln = Gd, Tb or Eu)

    Science.gov (United States)

    Viana, R. S.; Oliveira, C. A. F.; Chojnacki, J.; Barros, B. S.; Alves-Jr, S.; Kulesza, J.

    2017-07-01

    Lanthanide-calixarene hybrid materials are of particular interest due to the combination of the interesting properties of the ligand cavity-like structure and the luminescent features of lanthanides. The aim of this study was to synthesize and investigate the photophysical properties of Eu3+, Tb3+ and Gd3+ hybrids based on calix[4]arene-tetracarboxylate. The preparation of two structurally different Tb3+ compounds (calix-TA-SC-Tb and calix-TA-Tb) was dictated by the ligand to metal molar ratio and the synthesis time. Analysis of calix-TA-SC-Tb monocrystals revealed the formation of a mononuclear complex of C2 symmetry containing Tb3+ coordinated by four calixarene ionized groups and formate anion encapsulated within the upper cavity. Syntheses of other hybrids failed in producing high-quality crystals and the structures could not be solved. The solid-state luminescent properties of hybrids were evaluated, and the structure/property relationship was investigated. Based on the emission and excitation spectra, the energy diagrams for calix-TA-Eu, calix-TA-Tb and calix-TA-Gd were proposed.

  12. Highly luminescent charge-neutral europium(iii) and terbium(iii) complexes with tridentate nitrogen ligands.

    Science.gov (United States)

    Senthil Kumar, Kuppusamy; Schäfer, Bernhard; Lebedkin, Sergei; Karmazin, Lydia; Kappes, Manfred M; Ruben, Mario

    2015-09-21

    We report on the synthesis of tridentate-nitrogen pyrazole-pyridine-tetrazole (L(1)H) and pyrazole-pyridine-triazole (L(2)H) ligands and their complexation with lanthanides (Ln = Gd(iii), Eu(iii) and Tb(iii)) resulting in stable, charge-neutral complexes Ln(L(1))3 and Ln(L(2))3, respectively. X-ray crystallographic analysis of the complexes with L(1) ligands revealed tricapped trigonal coordination geometry around the lanthanide ions. All complexes show bright photoluminescence (PL) in the solid state, indicating efficient sensitization of the lanthanide emission via the triplet states of the ligands. In particular, the terbium complexes show high PL quantum yields of 65 and 59% for L(1) and L(2), respectively. Lower PL efficiencies of the europium complexes (7.5 and 9%, respectively) are attributed to large energy gaps between the triplet states of the ligands and accepting levels of Eu(iii). The triplet state energy can be reduced by introducing an electron withdrawing (EW) group at the 4 position of the pyridine ring. Such substitution of L(1)H with a carboxylic ester (COOMe) EW group leads to a europium complex with increased PL quantum yield of 31%. A comparatively efficient PL of the complexes dissolved in ethanol indicates that the lanthanide ions are shielded against nonradiative deactivation via solvent molecules.

  13. Interleukin-1β and transforming growth factor-β cooperate to induce neurosphere formation and increase tumorigenicity of adherent LN-229 glioma cells.

    Science.gov (United States)

    Wang, Lei; Liu, Ziyan; Balivada, Sivasai; Shrestha, Tej; Bossmann, Stefan; Pyle, Marla; Pappan, Loretta; Shi, Jishu; Troyer, Deryl

    2012-02-10

    Glioma stem cells (GSCs) have the property of self-renewal and appear to be a driving force for the initiation and recurrence of gliomas. We recently found that the human tumorigenic LN-229 glioma cell line failed to form neurospheres in serum-free conditions and generated mostly small tumors in vivo, suggesting that either LN-229 GSCs are not active in these conditions or GSCs are absent in the LN-229 cell line. Using self-renewal assay, soft-agar colony assay, cell proliferation assay, invasion assay, real time PCR analysis, ELISA and in vivo tumorigenic assay, we investigated the effects of interleukin (IL)-1β and transforming growth factor (TGF)-β on the development of GSCs from LN-229 cells. Here, we demonstrate that the combination of IL-1β and TGF-β can induce LN-229 cells to form neurospheres in serum-free medium. IL-1β/TGF-β-induced neurospheres display up-regulated expression of stemness factor genes (nestin, Bmi-1, Notch-2 and LIF), and increased invasiveness, drug resistance and tumor growth in vivo: hallmarks of GSCs. These results indicate that IL-1β and TGF-β cooperate to induce a GSC phenotype in the LN-229 cell line. Induction of nestin, LIF and Notch-2 by IL-1β/TGF-β can be reverted after cytokine withdrawal. Remarkably, however, up-regulated Bmi-1 levels remained unchanged after cytokine withdrawal; and the cytokine-withdrawn cells maintained strong clonogenicity, suggesting that Bmi-1 may play a crucial role in tumorigenesis. Our finding indicates that glioma cells without self-renewal capability in standard conditions could also contribute to glioma malignancy when cytokines, such as IL-1β and TGF-β, are present in the tumor environment. Targeting GSC-promoting cytokines that are highly expressed in glioblastomas may contribute to the development of more effective glioma therapies.

  14. LaF3:Ln mesoporous spheres: controllable synthesis, tunable luminescence and application for dual-modal chemo-/photo-thermal therapy.

    Science.gov (United States)

    Lv, Ruichan; Yang, Guixin; He, Fei; Dai, Yunlu; Gai, Shili; Yang, Piaoping

    2014-12-21

    In this report, uniform LaF(3):Ln mesoporous spheres have been synthesized by a facile and mild in situ ion-exchange method using yolk-like La(OH)3:Ln mesoporous spheres as templates, which were prepared through a self-produced bubble-template route. It was found that the structures of the final LaF(3):Ln can simply be tuned by adding a polyetherimide (PEI) reagent. LaF(3):Ln hollow mesoporous spheres (HMSs) and LaF(3):Ln flower-like mesoporous spheres (FMSs) were obtained when assisted by PEI and in the absence of PEI. The up-conversion (UC) luminescence results reveal that the doping of Nd(3+) ions in LaF(3):Ln can markedly influence the UC emissions of the products. It is interesting that an obvious thermal effect is achieved due to the energy back-transfer from Tm(3+) to Nd(3+) ions under 980 nm near-infrared (NIR) irradiation. The LaF(3):Yb/Er/Tm/Nd HMSs show good biocompatibility and sustained doxorubicin (DOX) release properties. In particular, upon 980 nm NIR irradiation, the photothermal effect arising from the Nd(3+) doping induces a faster DOX release from the drug release system. Moreover, UC luminescence images of LaF(3):Yb/Er/Tm/Nd HMSs uptaken by MCF-7 cells exhibit apparent green emission under 980 nm NIR irradiation. Such a multifunctional carrier combining UC luminescence and hyperthermia with the chemotherapeutic drugs should be of high potential for the simultaneous anti-cancer therapy and cell imaging.

  15. Complexes of light lanthanides with 2,4-dimethoxybenzoic acid

    Directory of Open Access Journals (Sweden)

    WIESLAWA FERENC

    2000-01-01

    Full Text Available The complexes of light lanthanides with 2,4-dimethoxybenzoic acid of the formula: Ln(C9H9O43·nH2O where Ln = La(III, Ce(III, Pr(III, Nd(III, Sm(III, Eu(III, Gd(IIII, and n = 3 for La(III, Gd(III, n = 2 for Sm(III, Eu(III, and n = 0 for Ce(III, Pr(III, Nd(III have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric studies and X-ray diffraction measurements. The complexes have colours typical for Ln3+ ions (La, Ce, Eu, Gd-white, Sm-cream, Pr-green, Nd-violet. The carboxylate group in these complexes is a symmetrical, bidentate, chelating ligand. They are crystalline compounds characterized by various symmetry. On heating in air to 1273 K the 2,4-dimethoxybenzoates of the light lanthanides decompose in various ways. The hydrated complexes decompose in two or three steps while those of anhydrous ones only in one or two. The trihydrate of lanthanum 2,4-dimethoxybenzoate first dehydrates to form the anhydrous salt, which then decomposes to La2O3via the intermediate formation of La2O2CO3. The hydrates of Sm(III, Eu(III, Gd(III decompose in two stages. First, they dehydrate forming the anhydrous salts, which then decompose directly to the oxides of the respective metals. The anhydrous complexes of Ce(III, Pr(III decompose in one step, while that of Nd(III in two. The solubilities of the 2,4-dimethoxybenzoates of the light lanthanides in water and ethanol at 293 K are in the order of: 10-3 mol dm-3 and 10-4-10-3 mol dm-3, respectively.

  16. Solid-State and solution studies of [Ln(n)(SiW11O39)] polyoxoanions: an example of building block condensation dependent on the nature of the rare earth.

    Science.gov (United States)

    Mialane, Pierre; Lisnard, Laurent; Mallard, Alain; Marrot, Jérôme; Antic-Fidancev, Elisabeth; Aschehoug, Patrick; Vivien, Daniel; Sécheresse, Francis

    2003-03-24

    The reactivity of the [alpha-SiW(11)O(39)](8-) monovacant polyoxometalate with lanthanide has been investigated for four different trivalent rare-earth cations (Ln = Nd(III), Eu(III), Gd(III), Yb(III)). The crystal structures of KCs(4)[Yb(alpha-SiW(11)O(39))(H(2)O)(2)] x 24H(2)O (1), K(0.5)Nd(0.5)[Nd(2)(alpha-SiW(11)O(39))(H(2)O)(11)] x 17H(2)O (2a), and Na(0.5)Cs(4.5)[Eu(alpha-SiW(11)O(39))(H(2)O)(2)] x 23H(2)O (3a) are reported. The solid-state structure of compound 1 consists of linear wires built up of [alpha-SiW(11)O(39)](8-) anions connected by Yb(3+) cations, while the linkage of the building blocks by Eu(3+) centers in 3a leads to the formation of zigzag chains. In 2a, dimeric [Nd(2)(alpha-SiW(11)O(39))(2)(H(2)O)(8)](10-) entities are linked by four Nd(3+) cations. The resulting chains are connected by lanthanide ions, leading to a bidimensional arrangement. Thus, the dimensionality, the organization of the polyoxometalate building units, and the Ln/[alpha-SiW(11)O(39)](8-) ratio in the solid state can be tuned by choosing the appropriate lanthanide. The luminescent properties of compound 3a have been studied, showing that, in solution, the polymer decomposes to give the monomeric complex [Eu(alpha-SiW(11)O(39))(H(2)O)(4)](5-). The lability of the four exogenous ligands connected to the rare earth must allow the functionalization of this lanthanide polyanion.

  17. Removal of rhodamine 6G dye contaminant by visible light driven immobilized Ca{sub 1−x}Ln{sub x}MnO{sub 3} (Ln = Sm, Ho; 0.1 ≤ x ≤ 0.4) photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Barrocas, B. [Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa (Portugal); Sério, S. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Rovisco, A. [Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Nunes, Y. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Jorge, M.E. Melo, E-mail: mdjorge@fc.ul.pt [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa (Portugal)

    2016-01-01

    Graphical abstract: - Abstract: Visible-light-driven Ca{sub 1−x}Ln{sub x}MnO{sub 3} (Ln = Sm, Ho; 0.1 ≤ x ≤ 0.4) films were grown by RF-magnetron sputtering onto fused silica substrates. The effects of Ca{sup 2+} substitution for Ho{sup 3+} or Sm{sup 3+} in Ca{sub 1−x}Ln{sub x}MnO{sub 3} on the structural, morphological and photocatalytic properties for rhodamine 6G dye degradation under visible light irradiation were investigated. XRD showed a pure typical perovskite phase for all the prepared films, except for Ca{sub 0.9}Ho{sub 0.1}MnO{sub 3} and a decrease of the crystallite size with the increase of the amount of ion substituted. SEM and AFM revealed that the films surface is dense, with low roughness. UV–vis spectroscopy indicated for the two series band gaps in the range of 1.6–2.8 eV, being lower for the films containing holmium. The results showed that some Ca{sub 1−x}Ho{sub x}MnO{sub 3} and Ca{sub 1−x}Sm{sub x}MnO{sub 3} films present higher photocatalytic activity for Rh6G degradation in comparison with TiO{sub 2} films and for the same x value the Ho-films exhibited higher photocatalytic activity. For both films series the maximal degradation rate was obtained for x = 0.2; above this content the degradation percentage exhibits a decreasing trend with the increase of Ho or Sm substitution, except for x = 0.4 in the case of Ho system, which is observed again an increase in the degradation rate. The Rh6G photocatalytic degradation followed a pseudo first-order reaction kinetics. XRD and SEM of the used photocatalysts evidenced high photochemical stability.

  18. Covalent co-immobilization of heparin/laminin complex that with different concentration ratio on titanium surface for selectively direction of platelets and vascular cells behavior

    Science.gov (United States)

    Wang, Jian; Chen, Yuan; Liu, Tao; Wang, Xue; Liu, Yang; Wang, Yuan; Chen, Junying; Huang, Nan

    2014-10-01

    Surface biofunctional modification of coronary artery stent to improve the hemocompatibility and selectively accelerate endothelium regeneration but prevent restenosis have been become a new hotspot. For this, a novel method was developed in this work by co-immobilization of Ln and heparin complex on poly-L-lysine modified Ti surface. Take the advantage of the specific interaction between Ln and heparin, Ln and heparin complexes with different concentration ratios were set up for creating different exposure density of these two types of biomolecules. According to biocompatibility evaluation results, the Hep/Ln complexes modified surface displayed less platelet adhesion and activation. Especially, on L(150)H and L(200)H surface, the AT III binding quantity, APTT value and anti-coagulation property of modified surface were significantly promoted. Furthermore, the adherent density and proliferation activity of ECs and EPCs were positively correlated with Ln concentration. Notably, the proliferation of both ECs and EPCs on L(100)H, L(150)H and L(200)H surface were greatly promoted. Another hand, the proliferation activity of SMCs was significantly inhibited on Hep/Ln modified surfaces, which was considered mainly due to the inhibitory effect of heparin to SMCs. According to the existing results, this study demonstrated that in a certain range of heparin and laminin concentration ratio, the biological behavior of platelets, ECs, EPCs and SMCs could be selectively directed. We suggested that this article provided a potential method to construct an adequate platform on a stent surface for accelerate endothelialization with low side effects.

  19. Crystal structures of [Ln(NO33(μ2-bpydo2], where Ln = Ce, Pr or Nd, and bpydo = 4,4′-bipyridine N,N′-dioxide: layered coordination networks containing 44 grids

    Directory of Open Access Journals (Sweden)

    Michael L. Stromyer

    2016-01-01

    Full Text Available Three isostructural coordination networks of Ce, Pr, and Nd nitrate with 4,4′-bipyridine N,N′-dioxide (bpydo are reported, namely poly[[tris(nitrato-κ2O,O′cerium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Ce(NO33(C10H8N2O22], poly[[tris(nitrato-κ2O,O′praeseodymium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Pr(NO33(C10H8N2O22], and poly[[tris(nitrato-κ2O,O′neodymium(III]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Nd(NO33(C10H8N2O22]. All three compounds are isostructural to the previously reported La analogue. The asymmetric unit of [Ln(NO33(μ2-bpydo2] contains one lanthanide cation, two bpydo ligands, and three nitrate anions. Both bpydo ligands act as end-to-end μ2-bridges and display nearly ideal cis and gauche conformations, respectively. The bpydo ligands link the ten-coordinate LnIII cations, forming interdigitating 44 grid-like layers extending parallel to (-101, where interdigitation of layers is promoted by C—H...O interactions between nitrate anions and bpydo ligands. The interdigitated layers are linked to sets of neighboring layers via further C—H...O and π–π interactions.

  20. Cationic ordering and role of the B-site lanthanide(III) and molybdenum(V) cations on the structure and magnetism of double perovskites Sr{sub 2}LnMoO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Pinacca, R.M.; Larrégola, S.A.; López, C.A. [INTEQUI-Área de Química General e Inorgánica “Dr. G.F. Puelles”, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Pedregosa, J.C., E-mail: jpedreg@gmail.com [INTEQUI-Área de Química General e Inorgánica “Dr. G.F. Puelles”, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Pomjakushin, Vladimir [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Sánchez, R.D. [Centro Atómico Bariloche, Comisión Nacional de Energía Atómica and Instituto Balseiro, Universidad Nacional de Cuyo, 8400 S.C. de Bariloche, Río Negro (Argentina); Alonso, J.A. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)

    2015-06-15

    Highlights: • Five new double perovskites of formula Sr{sub 2}LnMoO{sub 6} were synthesized. • All the samples crystallize in the monoclinic P2{sub 1}/n space group. • Strong reducing conditions were used in order to stabilized Mo(V) cations. • A complete ordering between the rare earth and molybdenum ions was observed. • Magnetism agrees with the crystal distortions observed from Rietveld analysis. - Abstract: We describe the preparation, crystal structure determination and magnetic properties of a new series of ordered double perovskite oxides Sr{sub 2}LnMoO{sub 6} (Ln = Eu, Gd, Dy, Ho, Er, Yb) with Mo{sup 5+} and Ln{sup 3+} electronic configurations. These compounds have been obtained by solid state reaction under reducing conditions in order to stabilize Mo{sup 5+} cations. Structural characterization by XRPD and NPD was performed when Ln = Ho, Er, Yb and just XRPD for absorbing Ln = Eu, Gd, Dy. At room temperature, an excellent Rietveld fit was obtained for all the samples in a monoclinic symmetry, space group P2{sub 1}/n, with long-range ordering of Ln and Mo atoms. Magnetic susceptibility measurements show that some of these materials present magnetic ordering below 25 K and the determined effective magnetic moments are consistent with those expected for the pair Ln{sup 3+}–Mo{sup 5+}. All the phases have negative values​​ of the Weiss temperature indicating dominance of antiferromagnetic interactions.

  1. Facile synthesis of NaYF4:Yb, Ln/NaYF4:Yb core/shell upconversion nanoparticles via successive ion layer adsorption and one-pot reaction technique

    NARCIS (Netherlands)

    Zeng, Q.; Xue, B.; Zhang, Y.; Wang, D.; Liu, X.; Tu, L.; Zhao, H.; Kong, X.; Zhang, H.

    2013-01-01

    The facile one-pot synthesis of NaYF4:Yb, Ln/NaYF4:Yb core/shell (CS) upconversion nanoparticles (UCNPs) was firstly developed through the successive ion layer adsorption and reaction (SILAR) technique, which represents an attractive alternative to conventional synthesis utilizing the chloride of Ln

  2. Synthesis, structural and physico-chemical characterization of new defect pyrochlore-type antimonates K{sub 0.42}Ln{sub y'}Sb{sub 2}O{sub 6+z'} and Na{sub 0.36}Ln{sub y}Sb{sub 2}O{sub 6+z} (0Ln=Y, Eu and Gd) prepared by soft chemistry route

    Energy Technology Data Exchange (ETDEWEB)

    El Haimouti, A.; Zambon, D.; El-Ghozzi, M.; Avignant, D.; Leroux, F.; Daoud, M.; El Aatmani, M

    2004-01-28

    Most of the pyrochlore-type compounds known and reported in the literature were prepared by solid state reactions, at elevated temperature ({approx}1100 deg. C). Alternatively, a new series of compounds, with formula K{sub 0.42}Ln{sub y'}Sb{sub 2}O{sub 6+z'} and Na{sub 0.36}Ln{sub y}Sb{sub 2}O{sub 6+z} (with 0Ln=Y, Eu and Gd) was isolated, using a soft chemistry route from solutions. The good crystallinity of the samples allowed their structural determination using Rietveld refinement from X-ray powder diffraction data. They show a defect pyrochlore-type structure, with Fd3m space group and unit cell parameters close to 10.28 A. The occupied sites are: (Na, Ln) in site 16d, Sb in site 16c, O in site 48f, K and O' in site 8b.

  3. Bimetallic Complexes Supported by a Redox-Active Ligand with Fused Pincer-Type Coordination Sites.

    Science.gov (United States)

    Wang, Denan; Lindeman, Sergey V; Fiedler, Adam T

    2015-09-08

    The remarkable chemistry of mononuclear complexes featuring tridentate, meridionally chelating "pincer" ligands has stimulated the development of ligand frameworks containing multiple pincer sites. Here, the coordination chemistry of a novel pentadentate ligand (L(N3O2)) that provides two closely spaced NNO pincer-type compartments fused together at a central diarylamido unit is described. The trianionic L(N3O2) chelate supports homobimetallic structures in which each M(II) ion (M = Co, Cu, Zn) is bound in a meridional fashion by the bridging diarylamido N atom and O,N-donors of the salicyaldimine arms. The metal centers are also coordinated by a mono- or bidentate auxiliary ligand (L(aux)), resulting in complexes with the general form [M2(L(N3O2))(L(aux))2](+) (where L(aux) = 1-methyl-benzimidazole (1MeBI), 2,2'-bipyridine (bpy), 4,4'-dibromo-2,2'-bipyridine (bpy(Br2)), or (S)-2-(4-isopropyl-4,5-dihydrooxazolyl)pyridine (S-(iPr)OxPy)). The fused nature of the NNO pincer sites results in short metal-metal distances ranging from 2.70 Å for [Co2(L(N3O2)) (bpy)2](+) to 3.28 Å for [Zn2(L(N3O2)) (bpy)2](+), as revealed by X-ray crystallography. The complexes possess C2 symmetry due to the twisting of the aryl rings of the μ-NAr2 core; spectroscopic studies indicate that chiral L(aux) ligands, such as S-(iPr)OxPy, are capable of controlling the helical sense of the L(N3O2) scaffold. Since the four- or five-coordinate M(II) centers are linked solely by the amido moiety, each features an open coordination site in the intermetallic region, allowing for the possibility of metal-metal cooperativity in small-molecule activation. Indeed, the dicobalt(II) complex [Co2(L(N3O2)) (bpy(Br2))2](+) reacts with O2 to yield a dicobalt(III) species with a μ-1,2-peroxo ligand. The bpy-containing complexes exhibit rich electrochemical properties due to multiple metal- and ligand-based redox events across a wide (3.0 V) potential window. Using electron paramagnetic resonance (EPR

  4. Digitální zpracování fotografií sítnice

    OpenAIRE

    Kadlas, Matyáš

    2015-01-01

    Cíl bakalářské práce je vytvořit text, který má za úkol seznámit čtenáře s teorií a konverzí barevných prostorů, úpravou snímků sítnice, anatomií oka a metodami snímání sítnice. Bakalářská práce dále popisuje proces konverze a úpravy snímků sítnice, který je použit ve finálním programu. Goal of bachelor thesis is to create text that is designed to acquaint the reader with the theory and conversion of colour spaces, image editing, anatomy of the eye and retina scanning methods. Bachelor the...

  5. Process parameter optimization during EDM of AISI 316 LN stainless steel by using fuzzy based multi-objective PSO

    Energy Technology Data Exchange (ETDEWEB)

    Majumder, Arindam [National Institute of Technology Agartala, Tripura (India)

    2013-07-15

    The present contribution describes an application of a hybrid approach using fuzzy logic and particle swarm optimization (PSO) for optimizing the process parameters in the electric discharge machining (EDM) of AISI 316LN Stainless Steel. In this study, each experimentation was performed under different machining conditions of pulse current, pulse on-time, and pulse off-time. Machining performances such as MRR and EWR were evaluated. A Taguchi L9 orthogonal array was produced to plan the experimentation and the regression method was applied to model the relationship between the input factors and responses. A fuzzy model was employed to provide a fitness function to PSO by unifying the multiple responses. Finally, PSO was used to predict the optimal process parametric settings for the multi-performance optimization of the EDM operation. The experimental results confirm the feasibility of the strategy and are in good agreement with the predicted results over a wide range of machining conditions employed in the process.

  6. Assessment of Cavitation-Erosion Resistance of 316LN Stainless Steel Following a Nitro-Carburizing Surface Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J [ORNL

    2009-11-01

    A nitro-carburizing surface treatment known domestically as the Melonite process was applied to type 316LN stainless steel test pieces and exposed to sonication conditions in mercury using a vibratory horn technique. Cavitation-erosion damage was evaluated for extended exposures and compared to other surface treatments on the same substrate alloy. The results indicate that the Melonite process substantially retards weight loss and crater development for extended periods, but gradually is eroded/destroyed leading to exposure of the substrate and cavitation-erosion behavior similar to untreated specimens. Compared with other surface treatments, cavitation-erosion results indicate that specimens treated with Melonite perform similarly to specimens treated with a simple nitriding process. Neither the simple nitriding nor the Melonite treatment is quite as effective as a previously evaluated low temperature carburizing treatment, the latter being about a factor of three better than Melonite in terms of weight loss during sonication in mercury.

  7. Novel core-shell structure microspheres based on lanthanide complexes for white-light emission and fluorescence sensing.

    Science.gov (United States)

    Lian, Xiao; Yan, Bing

    2016-02-14

    A series of new core-shell structure materials based on lanthanide complexes [H2NMe2]3[Ln(dpa)3] (Ln = Eu, Tb, Sm, Dy, Nd, and Yb; [H2NMe2](+) = dimethylamino cation; dpa = 2-dipicolinate) and silica microspheres has been prepared under solvothermal conditions. Electron microscopy reveals that the nanosized materials SiO2@Ln-dpa are spherical with a narrow size distribution and a [H2NMe2]3[Ln(L)3] coating was generated on the surface of silica microspheres successfully. The core-shell structure materials exhibit excellent optical performance. The white-light-emitting material SiO2@(Dy:Eu)-dpa has a potential application in the development of a white-light device, as a result of the fact that its CIE chromaticity coordinate is very close to that of pure white. Then, we selected SiO2@Eu-dpa as a representative sample for sensing experiments. Eventually, we found that the core-shell structure sensors are highly selective and sensitive for acetone and Cu(2+) cations. The detection of Cu(2+) in the human body is an important issue. Interestingly, the core-shell structure materials display better selectivity and higher sensitivity than the pure lanthanide complexes in sensing Cu(2+) and the value of the quenching effect coefficient has increased by more than 20%.

  8. Slow Relaxation of Magnetization in an Isostructural Series of Zinc-Lanthanide Complexes: An Integrated EPR and AC Susceptibility Study.

    Science.gov (United States)

    Amjad, Asma; Madalan, Augustin M; Andruh, Marius; Caneschi, Andrea; Sorace, Lorenzo

    2016-08-26

    We report the synthesis, structure, and spectroscopic and dynamic magnetic properties of a series of heterodinuclear complexes, [ZnLn(LH4 )2 ](NO3 )3 ⋅6 H2 O (Ln=Nd, Tb, Dy, Ho, Er, and Yb), with the singly deprotonated form of a new compartmentalized Schiff-base ligand, LH5 . The Ln(III) ions in these systems show a distorted square-antiprism geometry with an LnO8 coordination sphere. EPR spectroscopy and DC magnetic studies have shown that the anisotropic nature of the complexes is far more complicated than predicted on the basis of a simple electrostatic model. Among the investigated systems, only the Dy(III) derivative showed single-ion magnet behavior, in zero and an applied magnetic field, both in pure polycrystalline samples and in a series of polycrystalline samples with different degrees of dilution at the single-crystal level in the isostructural Y(III) derivative. The rich dynamics observed as functions of frequency, field, and temperature reveals that multiple relaxation mechanisms are at play, resulting in a barrier of 189 cm(-1) , which is among the highest reported for a dinuclear Zn-Dy system. Analysis of the dynamic behavior as a function of dilution degree further evidenced the persistence of non-negligible intermolecular interactions, even at the lowest concentration of 1 %. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Solution-combustion synthesis of Bi1–xLnxO1⋅5 (Ln = Y and La–Yb ...

    Indian Academy of Sciences (India)

    Unknown

    339–345. © Indian Academy of Sciences. 339. Solution-combustion synthesis of Bi1–xLnxO1⋅5 (Ln = Y and La–Yb) ... The lattice parameter of cubic phase increases linearly with size of the lanthanide ion. The syn- thesized powders are ... These synthetic methods have an advantage over the solid state methods in terms of.

  10. Modified diglycolamides for the An(III) + Ln(III) co-separation: evaluation by solvent extraction and time-resoved laser fluorescence spectroscopy

    NARCIS (Netherlands)

    Wilden, Andreas; Modolo, Giuseppe; Lange, Steve; Sadowski, Fabian; Beele, Bjorn B.; Skerencak- Frech, Andrej; Panak, Petra J.; Iqbal, M.; Verboom, Willem; Bosbach, Dirk

    2014-01-01

    The use of two recently developed diglycolamide-based extractants for the co-separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) is described and compared to the well-known extractant TODGA (N,N,N’,N’-tetraoctyl diglycolamide). The addition of one or two methyl groups to the

  11. Bis(pentamethylene)urea complexes of the lanthanide nitrates: synthesis, characterization, properties

    Science.gov (United States)

    de Souza, H. K. S.; Pedrosa, A. M. Garrido; Marinho, E. P.; Batista, M. K. S.; Melo, D. M. Araújo; Zinner, K.; Zinner, L. B.; Zukerman-Schpector, J.; Vicentini, G.

    2003-02-01

    Lanthanide nitrate complexes of bis(pentamethylene)urea (BPMU) with general formula Ln(NO 3) 33BPMU, where Ln: La, Nd, Sm, Eu, Ho and Er have been prepared and characterized based on CHN elemental analyses, lanthanide titration with EDTA, molar conductivity, spectroscopic data and thermal studies. The infrared spectra show that ligands (BPMU) are bonded through the carbonyl oxygen, nitrate counter-ions are bidentate linked to the central ions. The structure of the neodymium complex was determined. The crystal is monoclinic, P2 1/c, Z=4, with the following parameters: a=10.148(1) Å, b=21.879(2), c=19.154(2) Å, β=104.11(1)°, V=4124.3(7) Å 3. The polyhedron is a distorted tricapped trigonal prism, coordination number nine.

  12. Preparation and properties of rare earth element complexes with pyridine-2,6-dicarboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Brzyska, Wanda; Ozga, Wanda (Department of Inorganic and General Chemistry, Marie Curie Skodowska University, Lublin (Poland))

    1994-12-12

    The conditions of the formation of rare earth element (Y, La-Lu) dipicolinates were studied, and their quantitative compositions and solubilities in water at 293 K were determined (10[sup -2] to 10[sup -3] mol dm[sup -3]). The IR spectra of the hydrated complexes were recorded and their thermal decomposition in air was determined. During heating the hydrated dipicolinates Ln[sub 2](C[sub 7]H[sub 3]NO[sub 4])[sub 3][center dot]nH[sub 2]O (n=9-25) lose some or all of their water molecules of crystallization water in one, two or three steps; then the anhydrous or hydrated complexes decompose either directly to the oxides (Y, Ce, Sm-Dy, Tm-Lu) or with intermediate formation of oxocarbonates Ln[sub 2]O[sub 2]CO[sub 3] (La, Pr, Nd, Ho, Er).

  13. Positron annihilation studies in binary solid solutions and mechanical mixtures of lanthanide dipivaloylmethanate complexes

    Energy Technology Data Exchange (ETDEWEB)

    Fulgêncio, F., E-mail: fefulgencio@gmail.com [Departamento de Química, ICEx, Universidade Federal de Minas Gerais – UFMG, C.P. 702, CEP 31270-901 – Belo Horizonte, MG (Brazil); Oliveira, F.C. [Grupo de Pesquisa em Nanociências e Nanomateriais, Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG), Campus Timóteo, Timóteo, MG (Brazil); Windmöller, D.; Araujo, M.H.; Marques-Netto, A.; Machado, J.C. [Departamento de Química, ICEx, Universidade Federal de Minas Gerais – UFMG, C.P. 702, CEP 31270-901 – Belo Horizonte, MG (Brazil); Magalhães, W.F., E-mail: welmag@ufmg.br [Departamento de Química, ICEx, Universidade Federal de Minas Gerais – UFMG, C.P. 702, CEP 31270-901 – Belo Horizonte, MG (Brazil)

    2015-11-05

    Highlights: • Positronium formation in several Ln{sup 3+} complexes, except in Eu{sup 3+} complexes. • Positron annihilation spectroscopies used as a characterization tool of solid solutions and mechanical mixtures. • Measurements performed at different temperatures (80 and 295 K). - Abstract: Measurements using positron annihilation lifetime (PALS) and Doppler broadening annihilation radiation lineshape (DBARLS) spectroscopies were performed in several lanthanide dipivaloylmethanate complexes, Ln(dpm){sub 3} where Ln = Sm{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Ho{sup 3+}, Er{sup 3+}, Yb{sup 3+} and dpm = 2,2,6,6-tetramethyl-3,5-pentanedionate, and also on their binary solid solutions and mechanical mixtures, biphasic systems, of the general formula Ln{sub 1−x}Eu{sub x}(dpm){sub 3}. Expressive positronium formation was observed in all Ln(dpm){sub 3} complexes, except in Eu(dpm){sub 3} complex. The results indicate formation of solid solutions in the Sm{sup 3+}, Gd{sup 3+}and Tb{sup 3+} systems, where total inhibition of positronium formation was observed. A Stern–Volmer type equation, I{sub 3}{sup 0}/I{sub 3} = 1 + kx, was used to fit the data, enabling the calculation of the inhibition constants, k. A mechanical mixture behavior, with linear variation of I{sub 3} between the I{sub 3} values of the pure complexes, was observed in systems containing Ho{sup 3+}, Er{sup 3+} and Yb{sup 3+} complexes, where no effective solid solution formation occurred due to differences between the crystalline structures of these complexes and Eu(dpm){sub 3}. No positronium quenching reactions were observed in the solid solutions. DBARLS results confirmed those of PALS, evidencing that the positron annihilation spectroscopies are useful techniques to characterize the formation of solid solutions. PALS measurements at 80 K were performed in the Sm{sub 1−x}Eu{sub x}(dpm){sub 3} and Gd{sub 1−x}Eu{sub x}(dpm){sub 3} solid solutions. The results indicate that, despite a contraction

  14. Complexity explained

    CERN Document Server

    Erdi, Peter

    2008-01-01

    This book explains why complex systems research is important in understanding the structure, function and dynamics of complex natural and social phenomena. Readers will learn the basic concepts and methods of complex system research.

  15. Host composition dependent tunable multicolor emission in the single-phase Ba2(Ln(1-z)Tb(z))(BO3)2Cl:Eu phosphors.

    Science.gov (United States)

    Xia, Zhiguo; Zhuang, Jiaqing; Meijerink, Andries; Jing, Xiping

    2013-05-14

    A new strategy based on the host composition design has been adopted to obtain efficient color-tunable emission from Ba2Ln(0.97-z)Tb(z)(BO3)2Cl:0.03Eu (Ln = Y, Gd and Lu, z = 0-0.97) phosphors. This study reveals that the single-phase Ba2Ln(1-z)Tb(z)(BO3)2Cl compounds can be applied to use allowed Eu(2+) absorption transitions to sensitize Eu(3+) emission via the energy transfer Eu(2+) → (Tb(3+))n → Eu(3+). The powder X-ray diffraction (XRD) and Rietveld refinement analysis shows single-phase Ba2Ln(1-z)Tb(z)(BO3)2Cl. As-prepared Ba2Ln(0.97-z)Tb(z)(BO3)2Cl:0.03Eu phosphors show intense green, yellow, orange and red emission under 377 nm near ultraviolet (n-UV) excitation due to a variation in the relative intensities of the Eu(2+), Tb(3+) and Eu(3+) emission depending on the Tb content (z) in the host composition, allowing color tuning. The variation in emission color is explained by energy transfer and has been investigated by photoluminescence and lifetime measurements and is further characterized by the Commission Internationale de l'éclairage (CIE) chromaticity indexes. The quantum efficiencies of the phosphors are high, up to 74%, and show good thermal stabilities up to 150 °C. This investigation demonstrates the possibility to sensitize Eu(3+) line emission by Eu(2+)via energy migration over Tb(3+) resulting in efficient color tunable phosphors which are promising for use in solid-state white light-emitting diodes (w-LEDs).

  16. Ab initio calculation of excess properties of La{sub 1−x}(Ln,An){sub x}PO{sub 4} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany); Kowalski, Piotr M., E-mail: p.kowalski@fz-juelich.de [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany); Blanca-Romero, Ariadna [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany); Vinograd, Victor [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); Institute of Geoscience, Goethe Universität Frankfurt am Main, Altenhöferallee 1, 60438 Frankfurt (Germany); Bosbach, Dirk [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany)

    2014-12-15

    We used ab initio computational approach to predict the excess enthalpy of mixing and the corresponding regular/subregular model parameters for La{sub 1−x}Ln{sub x}PO{sub 4} (Ln=Ce,…, Tb) and La{sub 1−x}An{sub x}PO{sub 4} (An=Pu, Am and Cm) monazite-type solid solutions. We found that the regular model interaction parameter W computed for La{sub 1−x}Ln{sub x}PO{sub 4} solid solutions matches the few existing experimental data. Within the lanthanide series W increases quadratically with the volume mismatch between LaPO{sub 4} and LnPO{sub 4} endmembers (ΔV=V{sub LaPO{sub 4}}−V{sub LnPO{sub 4}}), so that W(kJ/mol)=0.618(ΔV(cm{sup 3}/mol)){sup 2}. We demonstrate that this relationship also fits the interaction parameters computed for La{sub 1−x}An{sub x}PO{sub 4} solid solutions. This shows that lanthanides can be used as surrogates for investigation of the thermodynamic mixing properties of actinide-bearing solid solutions. - Highlights: • The excess enthalpies of mixing for monazite-type solid solutions are computed. • The excess enthalpies increase with the endmembers volume mismatch. • The relationship derived for lanthanides is transferable to La{sub 1−x}An{sub x}PO{sub 4} systems.

  17. Fundamentální analýza akcie Nokia

    OpenAIRE

    Misárek, Aleš

    2011-01-01

    This bachelor thesis focuses on fundamental analysis of chosen stock, specifically Nokia's stock. In each of three levels of fundamental analysis -- economy, industry and stock valuation -- it's applying fundamentals of economic theory in practice. In economy fundamental analysis, the focus is put on identification of macroeconomic factors that affect development of stock markets and subsequent quantification of relationship between these factors and stock markets. Complex analysis of industr...

  18. Sociální aspekty agilních metodik vývoje softwaru

    OpenAIRE

    Čížek, Pavel

    2008-01-01

    Traditional methodologies of software development are burdened with number of problems, especially its complexity, bureaucracy and sticking on detailed processes defined in advance. This all often mean overtiming and overpricing the project as well as other negative effects. Agile methodologies of software development pursue solving such problems. They are built on principles of team-work, communication and developers' relations and sharing their knowledge. These values are one of the most im...

  19. Creep-fatigue propagation of semi-elliptical crack at 650 deg. C in 316L(N) stainless steel plates with or without welded joints; Propagation de fissures semi-elliptiques en fatigue-fluage a 650 deg. C dans des plaques d'acier 316L(N) avec ou sans joints soudes

    Energy Technology Data Exchange (ETDEWEB)

    Curtit, F

    2000-07-01

    This study realised in LISN Laboratory of CEA Saclay, deals with the creep fatigue propagation of semi elliptical crack at the temperature of 650 deg C in 316L(N) stainless steel plates with or without welded joints. A vast majority of the studies on creep fatigue propagation models are based on specimen (CT) especially designed for crack propagation study. The PLAQFLU program performed in LISN laboratory deals with the application and adaptation of these models to complex crack shape, which are more representative of the cracks observed in industrial components. In this scope, we use propagation tests realised at the temperature of 650 deg C with wide plates containing semi elliptical defects. For some of them, the initial defect is machined in the middle of a welded joint, which constitute a privileged site for the crack initiation. The approach used in this study is based on global parameters of fracture mechanics. At first, tests on CT specimen are used in order to determine the propagation laws correlating the crack growth rate to the global parameters K or C{sup *}. These laws are then supposed to be intrinsic to our materials and are used to analysed the semi elliptical crack propagation. The analysis of the comportment of the crack during the hold time demonstrates the possibility to establish a correlation between the crack propagation both in the deepest and the surface point and the local value of C{sup *}. These correlations are coherent in the different points of the crack front for the different applied hold times, and they present a reasonably good agreement with the creep propagation law identified on CT specimen. The simulation of test performed on based metal specimen with a model of summation of both creep and pure fatigue crack growth gives acceptable results when the calculus of the simplified expression of C{sup *}{sub s} considers a continuous evolution of creep deformations rate during the all test. (author)

  20. Molecular spectrum of lanthanide complexes with 2,3-dichlorobenzoic acid and 2,2-bipyridine.

    Science.gov (United States)

    He, Shu-Mei; Sun, Shu-Jing; Zheng, Jun-Ru; Zhang, Jian-Jun

    2014-04-05

    With 2,3-dichlorobenzoic acid as the first ligands and 2,2'-bipyridine as the second ligands, the lanthanide complexes [Ln(2,3-DClBA)3bipy]2 [Ln=Nd(a), Sm(b), Eu(c), Tb(d), Dy(e), Ho(f)] have been synthesized. By using Infrared (IR) and Raman (R) spectra, the characteristics of the groups can be identified. The bands of lanthanide complexes have been analyzed and attributed, and clearly demonstrated with the use of the complementarity of IR and R. The experiment reveals that the bands of complexes are affected by lanthanide elements (Ln). The frequency of stretching vibration and breathing vibration of ring, together with the stretching vibration of the carbonyl group (νCO), tends to be rising as the atomic number of lanthanide increasing. Meanwhile, crystallography data demonstrate that the six carbonyl groups have different bond length and bond angle, which can lead to different vibration frequency. The second derivatives of IR show that there are multiple vibration frequencies existing in the symmetrical stretching vibration of the carbonyl group (νsCO). Therefore the second derivative of IR spectrum is a characteristic band of different coordination modes of carbonyl group. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Determination of the stability constants of lanthanum, praseodymium, europium, erbium and lutetium complexes with chloride ions; Determinacion de las constantes de estabilidad de los complejos de lantano, praseodimio, europio, erbio y lutecio con iones cloruro

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez R, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2008-07-01

    The stability constants of La{sup 3+}, Pr{sup 3+}, Eu{sup 3+}, Er{sup 3+} and Lu{sup 3+} chloride complexes were determined in perchloric acid media using a liquid-liquid extraction method. The dinonyl napthalene sulfonic acid in n-heptane was used as extractant. The lanthanide (Ln) concentrations were measured by a radiochemical (Eu and Lu) and a spectrophotometric (La, Pr, and Er) methods. In the last method, xylenol orange was used for the determinations at ph 6. The stability constants of lanthanum, praseodymium, erbium and lutetium chloride complexes were determined in 2, 3 and 4 M ionic strength and europium in 1, 2 and 3 M, at 303 K. The fitting of experimental data to the equations for the calculation of the stability constants, was carry out considering both one chemical species (LnCl{sup 2+}) or two chemical species (LnCl{sup 2+} and LnCl{sub 2}{sup +}). The Specific Ion Interaction Theory was applied to the values of log {beta}{sup I}{sub Ln},{sub Cl} and the first stability constants at zero ionic strength were calculated by extrapolation. The same theory could not be applied to the log {beta}{sup I}{sub Ln},{sub 2Cl}, due to its low abundance and the values determined for the stability constants were similar. The distribution diagrams of the chemical species were obtained using the program MEDUSA and considering log {beta}{sup I}{sub Ln},{sub CI}, log {beta}{sup I}{sub Ln},{sub 2CI} values obtained in this work and the hydrolysis constants taken from the literature. The lanthanide chloride complexes are present in solution at specific conditions of ionic strength, concentration and in the absence of hydrolysis. The log {beta}{sup I}{sub Ln},{sub Cl} data were related to the charge density and the corresponding equations were obtained. These equations could be used to determine the stability constants along the lanthanide series. (Author)

  2. Synthesis and characterisation of the n = 2 Ruddlesden–Popper phases Ln{sub 2}Sr(Ba)Fe{sub 2}O{sub 7} (Ln = La, Nd, Eu)

    Energy Technology Data Exchange (ETDEWEB)

    Gurusinghe, Nicola N.M. [School of Chemistry, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Figuera, Juand de la; Marco, José F. [Instituto de Quimica-Fisica “Rocasolano”, CSIC, Serrano 119, 28006 Madrid (Spain); Thomas, Michael F. [Department of Physics, University of Liverpool, Liverpool. L69 3BX (United Kingdom); Berry, Frank J., E-mail: f.j.berry.1@bham.ac.uk [School of Chemistry, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Greaves, Colin [School of Chemistry, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2013-09-01

    Graphical abstract: - Highlights: • Some Ruddlesden–Popper phases have been characterised. • Substitution on the A site influences cationic order. • The magnetic moment redirects with temperature - Abstract: A series of n = 2 Ruddlesden–Popper phases A{sub 2}B{sub 2}O{sub 7} of composition Ln{sub 2}Sr(Ba)Fe{sub 2}O{sub 7} (Ln = La, Nd, Eu) have been prepared. La{sub 2}SrFe{sub 2}O{sub 7} and La{sub 2}BaFe{sub 2}O{sub 7} crystallise in the tetragonal space group I4/mmm. The structures of Eu{sub 2}SrFe{sub 2}O{sub 7} and Nd{sub 2}SrFe{sub 2}O{sub 7} are best described in space group P4{sub 2}/mnm. Substitution on the A site with smaller lanthanide- and larger alkaline metal- ions leads to enhanced cationic order in these phases and reflects increasing differences in cationic radii. All the compounds are antiferromagnetically ordered between 298 and 2 K. In La{sub 2}SrFe{sub 2}O{sub 7} the magnetic moment lies along [1 1 0] at all temperatures between 298 and 2 K whereas in La{sub 2}BaFe{sub 2}O{sub 7} the magnetic moment at 298 K lies along the crystallographic x-axis but redirects from the [1 0 0] to the [1 1 0] direction between 210 and 190 K and is retained in this direction until 2 K. In Nd{sub 2}SrFe{sub 2}O{sub 7} the magnetic moment at 298 K lies along [1 1 0] but rotates from [1 1 0] to [0 0 1] between 17 and 9 K. A series of {sup 57}Fe Mössbauer spectra recorded from La{sub 2}SrFe{sub 2}O{sub 7} between 290 and 600 K indicate a magnetic ordering temperature of T{sub N} ≥ 535 K.

  3. Use of Electro-spray Ionization Mass Spectrometry (ESI-MS) for the characterization of complexes 'ligand - metallic cations' in solution

    Energy Technology Data Exchange (ETDEWEB)

    Berthon, Laurence; Zorz, Nicole; Lagrave, Stephanie; Gannaz, Benoit; Hill, Clement [CEA-Marcoule DEN-DRCP-SCPS-LCSE, BP 17171, 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    In the framework of nuclear waste reprocessing, separation processes of minor actinides from fission products are developed by Cea. In order to understand the mechanisms involved in the extraction processes, the 'ligand/metallic cation' complexes, formed in the organic phases are characterized by electro-spray-mass-spectrometry (ESI-MS). This paper deals with the extraction of lanthanides (III) and americium (III) cations by an organic phase composed of a malonamide or / and a dialkyl phosphoric acid, diluted in an aliphatic diluent. For the dialkyl phosphoric acid, Ln(DEHP){sub 3}(HDEHP){sub 3} complexes are observed and in the presence of a large excess of Ln(NO{sub 3}){sub 3}, dinuclear species are also observed. For the malonamide extractant, it appears that the complexes formed in the organic phase are of the Nd(NO{sub 3}){sub 3}D{sub x} type, with 2 {<=} x {<=} 4: their distributions depend on the ratio [Ln]/[DMDOHEMA]. When the two extractants are present in the organic phase, mixed 'Ln-malonamide-dialkyl phosphoric acid' species are observed. The influence of several parameters, such as extractant concentration, solute concentration, aqueous acidity and the nature of the cations (lanthanides or americium) are studied. (authors)

  4. Magnetic properties of Aurivillius lanthanide-bismuth (LnFeO3nBi4Ti3O12 (n = 1,2 layered titanates

    Directory of Open Access Journals (Sweden)

    Tartaj, J.

    2008-06-01

    Full Text Available Bismuth titanates of Aurivillius layer-structure (BiFeO3nBi4Ti3O12, are of great technological interest because of their applications as non-volatile ferroelectric memories and high-temperature piezoelectric materials. The synthesis and crystallographic characterization of a new family of compounds (LnFeO3nBi4Ti3O12 was recently reported, in which the layers consist of LnFeO3 perovskites with a lanthanide Ln3+ substituting diamagnetic Bi3+. We report herein the magnetic properties of bulk samples, with Ln = Nd, Eu, Gd and Tb, and n = 1 and 2. Single-layer materials are paramagnetic, similar to non-substituted bismuth titanate Bi5FeTi3O15, and show crystal field effects due to the crystallographic environment of Eu3+ and Tb3+. Several anomalies are detected in the magnetization M(T of double-layer (LnFeO32Bi4Ti3O12 compounds, related to the strong magnetism of Tb and Gd, since they weakly appear for Nd and they are absent in the VanVleck Eu3+ ion and in the parent Bi6Fe2Ti3O18 compound.Los titanatos de hierro y bismuto con estructura laminar tipo Aurivillius, (BiFeO3nBi4Ti3O12, tienen un gran interés tecnológico debido a sus aplicaciones como memorias ferroeléctricas no volátiles y como piezoeléctrico cerámico de alta temperatura. La síntesis y la caracterización cristalina de una nueva familia de compuestos (LnFeO3nBi4Ti3O12 han sido recientemente reportadas, en la que el catión diamagnético Bi3+ ha sido sustituido por los paramagnéticos Ln3+ en los bloques de perovskita. Se estudian las propiedades magnéticas de muestras cerámicas en volumen con Ln = Nd, Eu, Gd y Tb, y n = 1 y 2. Los materiales con n=1 son paramagnéticos y similares al no sustituido Bi5FeTi3O15, y muestran efectos de campo cristalino debido al entorno cristalino de Eu3+ y Tb3+. Se han detectado algunas anomalías en la magnetización M(T de los compuestos n=2 (LnFeO32Bi4Ti3O12 que están relacionadas con el fuerte magnetismo de Tb y Gd, que aparecen d

  5. Synthesis, thermodynamic properties and antibacterial activities of lanthanide complexes with 3,5-dimethoxybenzoic acid and 1,10-phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jun-Ru [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Ren, Shu-Xia [Material Science and Engineering School, Shijiazhuang Tiedao University, Shijiazhaung 050043 (China); Ren, Ning [Department of Chemistry, Handan College, Handan 056005 (China); Zhang, Jian-Jun, E-mail: jjzhang6@126.com [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Zhang, Da-Hai [Department of Chemistry, Handan College, Handan 056005 (China); Wang, Shu-Ping [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China)

    2013-11-20

    Graphical abstract: Four novel complexes ([Ln(3,5-DmeoxBA){sub 3}(phen)]{sub 2} (Ln = Tb(1), Dy(2), Er(3), Yb(4); 3,5-DmeoxBA = 3,5-dimethoxybenzoic acid; phen = 1,10-phenanthroline))were synthesized and characterized by elemental analysis, IR and TG/DSC-FTIR technology. Heat capacities of the four complexes were measured by differential scanning calorimetry (DSC). The antibacterial action of the four complexes on bacteria and fungus such as Escherichia coli, Staphylococcus aureus and Candida albicans were studied by filter paper approach. - Highlights: • Four novel complexes ([Ln(3,5-DmeoxBA){sub 3}(phen)]{sub 2} were synthesized and characterized. • The thermal decomposition processes of the title complexes were studied using the TG/DSC–FTIR coupling techniques. • The heat capacities of the complexes were measured by (DSC). • The antibacterial action of the four complexes on Escherichia coli, Staphylococcus aureus and Candida albicans were studied. - Abstract: Four lanthanide complexes with a general formula [Ln(3,5-DmeoxBA){sub 3}(phen)]{sub 2} (Ln = Tb(1), Dy(2), Er(3), Yb(4); 3,5-DmeoxBA = 3,5-dimethoxybenzoic acid; phen = 1,10-phenanthroline) were synthesized and characterized by elemental analysis, infrared spectra (IR), and thermogravimetric, differential scanning calorimetry techniques, combined with Fourier transform infrared (TG/DSC–FTIR) technology. The thermal decomposition processes of the four complexes were investigated by TG/DSC–FTIR techniques. Heat capacities were measured by DSC. The values of the experimental heat capacities were fitted to a polynomial equation with the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions (H{sub T} − H{sub 298.15} {sub K}), (S{sub T} − S{sub 298.15} {sub K}), and (G{sub T} − G{sub 298.15} {sub K}) were calculated. The antibacterial action of the four complexes on bacteria and fungus such as Escherichia coli, Staphylococcus aureus and

  6. Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N4S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

    Science.gov (United States)

    Widger, Leland R.; Jiang, Yunbo; Siegler, Maxime; Kumar, Devesh; Latifi, Reza; de Visser, Sam P.; Jameson, Guy N.L.; Goldberg, David P.

    2013-01-01

    The known iron(II) complex [FeII(LN3S)(OTf)] (1) was used as starting material to prepare the new biomimetic (N4S(thiolate)) iron(II) complexes [FeII(LN3S)(py)](OTf) (2) and [FeII(LN3S)(DMAP)](OTf) (3), where LN3S is a tetradentate bis(imino)pyridine (BIP) derivative with a covalently tethered phenylthiolate donor. These complexes were characterized by X-ray crystallography, UV-vis, 1H NMR, and Mössbauer spectroscopy, as well as electrochemistry. A nickel(II) analogue, [NiII(LN3S)](BF4) (5), was also synthesized and characterized by structural and spectroscopic methods. Cyclic voltammetric studies showed 1 – 3 and 5 undergo a single reduction process with E1/2 between −0.9 to −1.2 V versus Fc+/Fc. Treatment of 3 with 0.5% Na/Hg amalgam gave the mono-reduced complex [Fe(LN3S)(DMAP)]0 (4), which was characterized by X-ray crystallography, UV-vis, EPR (g = [2.155, 2.057, 2.038]) and Mössbauer (δ = 0.33 mm s−1; ΔEQ = 2.04 mm s−1) spectroscopies. Computational methods (DFT) were employed to model complexes 3 – 5. The combined experimental and computational studies show that 1 – 3 are 5-coordinate, high-spin (S = 2) FeII complexes, whereas 4 is best described as a 5-coordinate, intermediate-spin (S = 1) FeII complex antiferromagnetically coupled to a ligand radical. This unique electronic configuration leads to an overall doublet spin (Stotal = ½) ground state. Complexes 2 and 3 are shown to react with O2 to give S-oxygenated products, as previously reported for 1. In contrast, the mono-reduced 4 appears to react with O2 to give a mixture of S- and Fe-oxygenates. The nickel(II) complex 5 does not react with O2, and even when the mono-reduced nickel complex is produced, it appears to undergo only outer-sphere oxidation with O2. PMID:23992096

  7. Environmentální ekonomie a politika: hodnocení kurzu na VŠE v Praze

    Directory of Open Access Journals (Sweden)

    Petr Šauer

    2013-09-01

    Full Text Available Článek si klade za cíl prozkoumat různé aspekty výuky a studia environmentální ekonomie pomocí výzkumu provedeného v kurzu vyučovaném na Vysoké škole ekonomické v Praze. Dotazníkové šetření bylo zaměřené na postoje studentů vůči životnímu prostředí a na jejich hodnocení různých částí kurzu. Názory studentů byly posléze porovnány s jejich výsledky u závěrečné zkoušky a s úrovní aktivity, se kterou se zapojovali do diskusí během seminářů. Hlavní otázkou výzkumu bylo, zda studenti se zájmem o ekonomickou politiku a regionální ekonomiku považovali orientaci kurzu na životní prostředí za osobně přínosnou. A pokud ano, jakých aspektů kurzu si nejvíce cenili, v čem byl pro ně kurz přínosný, jaké preferovali informační zdroje a jakou roli v jejich přístupu ke studiu sehrál zájem o stav životního prostředí?Mezi nejdůležitější výsledky šetření lze zařadit obhajobu environmentální ekonomie jako užitečné součásti kurikula studenty z obou skupin, tj. „environmentalistů“ i „ne-environmentalistů“ (či dokonce „anti- environmentalistů“. Dále studenti kladně hodnotili možnost aktivního zapojení do diskusí a prezentací během seminářů. Vyvážené rozložení přednášek a seminářů s dostatečným prostorem pro hlubší diskusi byly zřejmě klíčovými faktory pro udržení zájmu studentů. Data nám neposkytla dostatečné informace pro konstrukci regresních modelů s rozumnou predikční silou vzhledem k výsledkům zkoušky. Výzvou pro další výzkum tak zůstává zkvalitnění analýzy přístupů ke studiu (tzv. learning strategies.

  8. Possibilities of Energy Recovery from Municipal Waste/ Možnosti Energetického Využití Komunálního Odpadu

    Directory of Open Access Journals (Sweden)

    Lapčík Vladimír

    2012-12-01

    Full Text Available Příspěvek shrnuje možnosti energetického využití komunálního odpadu. Popsána je historie spalování a energetického využití komunálního odpadu v Československu a poté v České republice. Pozornost je věnována třem v současnosti provozovaným zařízením na energetické využití komunálního odpadu v České republice (ZEVO Malešice, SAKO Brno a TERMIZO Liberec. Dále jsou uvedeny charakteristiky připravovaných zařízení na energetické využití komunálního odpadu v ČR. Všechna uvedená zařízení pracují v zásadě na bázi roštových kotlů s čištěním spalin na nejvyšší možné technické úrovni. Příspěvek také uvádí další technologie, které je možno využít pro energetické využití komunálních odpadů - jedná se o zplyňovací a pyrolýzní jednotky a plazmové technologie. Závěr příspěvku je věnován současné a budoucí situaci v oblasti energetického využití komunálních odpadů v České republice s ohledem na platné právní normy.

  9. Encapsulation of Ln(III) Ions/Dyes within a Microporous Anionic MOF by Post-synthetic Ionic Exchange Serving as a Ln(III) Ion Probe and Two-Color Luminescent Sensors.

    Science.gov (United States)

    Zhao, Shu-Na; Song, Xue-Zhi; Zhu, Min; Meng, Xing; Wu, Lan-Lan; Feng, Jing; Song, Shu-Yan; Zhang, Hong-Jie

    2015-06-26

    A new anionic framework {[Me2NH2]0.125[In0.125(H2L)0.25]⋅xDMF}n (1) with one-dimensional (1D) channels along the c axis of about 13.06×13.06 Å(2), was solvothermally synthesized and well characterized. Post-synthetic cation exchange of 1 with Eu(3+), Tb(3+), Dy(3+), Sm(3+) afforded lanthanide(III)-loaded materials, Ln(3+)@1, with different luminescent behavior, indicating that compound 1 could be used as a potential luminescent probe toward different lanthanide(III) ions. Additionally, compound 1 exhibits selective adsorption ability toward cationic dyes. Moreover, the RhB@1 realized the probing of different organic solvent molecules by tuning the energy transfer efficiency between two different emissions, especially for sensing DMF. This work highlights the practical application of luminescent guest@MOFs as sensors, and it paves the way toward other one/multi-color luminescent host-guest systems by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Structural, magnetic and luminescent properties of lanthanide complexes with N-salicylideneglycine.

    Science.gov (United States)

    Vančo, Ján; Trávníček, Zdeněk; Kozák, Ondřej; Boča, Roman

    2015-04-28

    A series of anionic heavy lanthanide complexes, involving the N-salicylideneglycinato(2-) Schiff base ligand (salgly) and having the general formula K[Ln(salgly)₂(H₂O)₂]∙H₂O (1-6), where Ln stands for Gd, Tb, Dy, Ho, Er and Tm, was prepared using the one-pot template synthesis. The complexes were thoroughly characterized by elemental and Thermogravimetric/Differential Thermal Analyses (TG/DTA), Fourier Transform Infrared Spectroscopy (FT-IR), and photoluminescence spectroscopies, electrospray-ionization mass spectrometry, and their magnetic properties were studied by temperature-dependent dc magnetic measurements using the superconducting quantum interference device (SQUID). The X-ray structure of the terbium(III) complex (2), representing the unique structure between the lanthanide complexes of N-salicylideneamino acids, was determined. The results of spectral and structural studies revealed the isostructural nature of the prepared complexes, in which the lanthanide ion is octacoordinated by two O,N,O-donor salgly ligands and two aqua ligands. The analysis of magnetic data confirmed that the complexes behave as paramagnets obeying the Curie law. The results of photoluminescence spectral studies of the complexes showed the different origin in their luminescent properties between the solid state and solution. An antenna effect of the Schiff base ligand was observed in a powder form of the complex only, while it acts as a fluorophore in a solution.

  11. Structural, Magnetic and Luminescent Properties of Lanthanide Complexes with N-Salicylideneglycine

    Directory of Open Access Journals (Sweden)

    Ján Vančo

    2015-04-01

    Full Text Available A series of anionic heavy lanthanide complexes, involving the N-salicylideneglycinato(2- Schiff base ligand (salgly and having the general formula K[Ln(salgly2(H2O2]∙H2O (1–6, where Ln stands for Gd, Tb, Dy, Ho, Er and Tm, was prepared using the one-pot template synthesis. The complexes were thoroughly characterized by elemental and Thermogravimetric/Differential Thermal Analyses (TG/DTA, Fourier Transform Infrared Spectroscopy (FT-IR, and photoluminescence spectroscopies, electrospray-ionization mass spectrometry, and their magnetic properties were studied by temperature-dependent dc magnetic measurements using the superconducting quantum interference device (SQUID. The X-ray structure of the terbium(III complex (2, representing the unique structure between the lanthanide complexes of N-salicylideneamino acids, was determined. The results of spectral and structural studies revealed the isostructural nature of the prepared complexes, in which the lanthanide ion is octacoordinated by two O,N,O-donor salgly ligands and two aqua ligands. The analysis of magnetic data confirmed that the complexes behave as paramagnets obeying the Curie law. The results of photoluminescence spectral studies of the complexes showed the different origin in their luminescent properties between the solid state and solution. An antenna effect of the Schiff base ligand was observed in a powder form of the complex only, while it acts as a fluorophore in a solution.

  12. Multireziduální metody pro stanovení pesticidů ve vodách

    OpenAIRE

    Bukáčková, Monika

    2010-01-01

    Tato bakalářská práce teoretického charakteru se zabývá multireziduálním stanovením pesticidů ve vodách. Zaměřuje se především na pesticidy tvořící rezidua v povrchových vodách, které vzhledem ke své toxicitě a perzistenci v prostředí vyžadují cílené sledování. V práci je uvedeno rozdělení pesticidů a jsou zde popsány jejich vlastnosti, toxicita a procesy odbourávání. Dále jsou zde popsány možnosti analytického stanovení, zejména metody plynové a kapalinové chromatografie s různými typy detek...

  13. Characterization of the Q parameter for evaluating creep crack growth rate for type 316LN stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ekaputra, I. M. W.; Park, Jae Young; Kim, Seon Jin [Pukyong National University, Busan (Korea, Republic of); Kim, Woo Gon; Kim, Eung Seon [KAERI, Daejeon (Korea, Republic of)

    2016-07-15

    In this study, the Q parameter was characterized to evaluate the Creep crack growth rate (CCGR) of type 316LN stainless steel. Creep crack growth (CCG) data were obtained by CCG tests under different applied loads at 600 .deg. C. An additional CCG test was conducted at 550 .deg. C to investigate the possible temperature dependence of the stress intensity factor. An equation using the Q parameter for evaluating CCGR was proposed, and this parameter was characterized and compared with the typical C fracture parameter, which is commonly used. The Q parameter exhibited good linearity of the data, exhibiting no nonlinearity-induced dual value at the early stage. The Q parameter was suitable for characterizing the CCGR regardless of different applied loads and types of steels. In addition, fracture microstructures near the crack revealed a typical intergranular fracture mode, and this fracture was dominantly propagated along the grain boundary. The cracks were developed by the growth and interlinking of cavities, which were attributed to the precipitates forming along the grain boundary.

  14. Preparation of Dual-Emitting Ln@UiO-66-Hybrid Films via Electrophoretic Deposition for Ratiometric Temperature Sensing.

    Science.gov (United States)

    Feng, Ji-Fei; Gao, Shui-Ying; Liu, Tian-Fu; Shi, Jianlin; Cao, Rong

    2018-02-14

    Engineering novel dual-emitting metal-organic frameworks (MOFs) with wide emission ranges for application as ratiometric temperature sensors is still a challenge. In this paper, two novel dual-emitting MOFs with intergrated lanthanide metals and luminescent ligand in a UiO-66-type structure, named Ln@UiO-66-Hybrid, were prepared via the combination of postsynthetic modification and postsynthetic exchange methods. Subsequently, the as-synthesized MOFs were deposited onto fluorine tin oxide substrates through electrophoretic deposition by taking advantage of the charges from the unmodified carboxylic groups of the MOFs. The as-prepared Tb@UiO-66-Hybrid and Eu@UiO-66-Hybrid films were applied to detect temperature changes. The resulting Tb@UiO-66-Hybrid film exhibited good temperature-sensing properties with a relative sensitivity of up to 2.76% K -1 in the temperature range of 303-353 K. In addition, the Eu@UiO-66-Hybrid film showed excellent temperature-sensing performance based on the energy transfer between the luminescent ligand (H 2 NDC) and europium ions with a relative sensitivity of up to 4.26% K -1 in the temperature range of 303-403 K.

  15. Laboratorní úloha Virtuální sítě typu OpenVPN

    OpenAIRE

    Kortus, Jiří

    2012-01-01

    Tato práce v úvodu popisuje principy virtuálních privátních sítí (VPN) a stručně zmiňuje hlavní protokoly a přístupy pro jejich realizaci. Následně se podrobněji zaměřuje na seznámení čtenáře s charakterem a vlastnostmi sítí OpenVPN. Uvádí jednotlivé rysy a možnosti, diskutuje jejich výhody a nevýhody. Dále se věnuje návrhu laboratorní práce zaměřené na použití OpenVPN. Diskutuje možnosti návrhu práce zejména z technického a didaktického hlediska. Na jejich základě představuje koncept laborat...

  16. Assessment of surface relief and short cracks under cyclic creep in a type 316LN austenitic stainless steel

    Science.gov (United States)

    Sarkar, Aritra; Nagesha, A.; Parameswaran, P.; Sandhya, R.; Laha, K.

    2015-12-01

    Formation of surface relief and short cracks under cyclic creep (stress-controlled fatigue) in type 316LN stainless steel was studied at temperatures ranging from ambient to 923 K using scanning electron microscopy technique. The surface topography and crack distribution behaviour under cyclic creep were found to be strong functions of testing temperature due to the difference in strain accumulation. At 823 K, surface relief mainly consisted of fine slip markings due to negligible accumulation of strain as a consequence of dynamic strain ageing (DSA) which led to an increase in the cyclic life. Persistent slip markings (PSM) with distinct extrusions containing minute cracks were seen to prevail in the temperature range 873-923 K, indicating a higher slip activity causing higher strain accumulation in the absence of DSA. Besides, a large number of secondary cracks (both transgranular and intergranular) which were partially accentuated by severe oxidation, were observed. Extensive cavitation-induced grain boundary cracking took place at 923 K, which coalesced with PSM-induced transgranular cracks resulting in failure dominated by creep that in turn led to a drastic reduction in cyclic life. Investigations on the influence of stress rate were also carried out which underlined the presence of DSA at 823 K. At 923 K, lowering the stress rate caused further strengthening of the contribution from creep damage marked by a shift in the damage mechanism from cyclic slip to diffusion.

  17. Application of Leak-Before-Break concept in 316LN austenitic steel pipes welded using 316L

    Directory of Open Access Journals (Sweden)

    Gabriel Giannini de Cunto

    2017-07-01

    Full Text Available The paper presents a study of the application of Leak-BeforeBreak (LBB concept in a relatively small-diameter high energy reactor coolant line, where it is proposed type AISI 316LN to be used as base material welded with type AISI 316L coated electrode considering a pipe with diameter of 273 mm. The pipe material was characterized in terms of tensile test with Ramberg-Osgood analyses and fracture toughness tests with J-Resistance curve determination, considering base material, weld joint and heat affected zones. For the mechanical properties found in tensile tests and using the PICEP software, were determined the leak rate curves versus crack sizes, to determine the size of a detectable leakage crack, and the critical crack sizes, considering failure by plastic collapse. For the critical crack sizes found in weld, which presented the lowest toughness, J-Integral analysis was performed considering failure by tearing instability. Results show a well-defined mechanical behavior where base material has a high toughness, weld has a low toughness, and HAZ showed intermediate properties. For the load limit analysis, the lowest critical crack size was found for base material presenting circumferential cracks. For J- Integral analysis, it was demonstrated that failure by tearing instability will not occur.

  18. Nitrogen effect on precipitation and sensitization in cold-worked Type 316L(N) stainless steels

    Science.gov (United States)

    Oh, Yong Jun; Hong, Jun Hwa

    2000-02-01

    The precipitation behavior and sensitization resistance of Type 316L(N) stainless steels containing different concentrations of nitrogen have been investigated at the aging condition of 700°C for cold work (CW) levels ranging from 0% (as solution annealed) to 40% reduction in thickness. The precipitation of M 23C 6 carbide and intermetallic compounds ( χ, Laves and σ phase) was accelerated by increasing the CW level. Nitrogen in the deformed alloys retarded the inter- and intra-granular precipitation of the carbides at low and high CW levels respectively, whereas it increased the relative amount of the χ phase. Quantitative assessment of the degree of sensitization (DOS) using the double loop-electrochemical potentiokinetic reactivation (DL-EPR) tests indicated that CW levels up to 20% enhanced sensitization while 40% CW suppressed sensitization for all aging times. The increase in nitrogen content accelerated the sensitization at CW levels below 20%. This might be associated with the homogeneous distribution of dislocations and the lower tendency toward recrystallization exhibited in the alloys having higher nitrogen content.

  19. Stable luminescent metal-organic frameworks as dual-functional materials to encapsulate ln(3+) ions for white-light emission and to detect nitroaromatic explosives.

    Science.gov (United States)

    Xie, Wei; Zhang, Shu-Ran; Du, Dong-Ying; Qin, Jun-Sheng; Bao, Shao-Juan; Li, Jing; Su, Zhong-Min; He, Wen-Wen; Fu, Qiang; Lan, Ya-Qian

    2015-04-06

    A stable porous carbazole-based luminescent metal-organic framework, NENU-522, was successfully constructed. It is extremely stable in air and acidic/basic aqueous solutions, which provides the strategy for luminescent material encapsulation of Ln(3+) ions with tunable luminescence for application in light emission. More importantly, Ln(3+)@NENU-522 can emit white light by encapsulating different molar ratios of Eu(3+) and Tb(3+) ions. Additionally, Tb(3+)@NENU-522 is found to be useful as a fluorescent indicator for the qualitative and quantitative detection of nitroaromatic explosives with different numbers of -NO2 groups, and the concentrations of complete quenching are about 2000, 1000, and 80 ppm for nitrobenzene, 1,3-dinitrobenzene, and 2,4,6-trinitrophenol, respectively. Meanwhile, Tb(3+)@NENU-522 displays high selectivity and recyclability in the detection of nitroaromatic explosives.

  20. Study of Ce0.9Tb0.05Ln0.05O1.975 compounds as ceramic pigments

    Directory of Open Access Journals (Sweden)

    Šulcová P.

    2008-01-01

    Full Text Available New inorganic pigments based on CeO2 were synthesized as high-temperature Environment friendly inorganic pigments. This work is focused on mixed oxides based on ceria which are doped by rare earth elements, i.e. compounds with formula Ce0.9Tb0.05Ln0.05O1.975, where Ln means lanthanides. The pigments were prepared by the solid state reaction. Their colour properties were investigated depending on content of selected lanthanides and calcination temperature. All prepared pigments were applied into organic matrix and ceramic glaze. The pigments were evaluated from the standpoint of their structure, colour properties and particle sizes.

  1. Complex Narratives

    NARCIS (Netherlands)

    Simons, J.; Buckland, W.

    2014-01-01

    In the opening chapter, "Complex Narratives," Jan Simons brings together narratology, game theory, and complexity theory to untangle the intricate nature of complex narratives in contemporary cinema. He presents an overview of the different concepts - forking path narratives, mind-game films,

  2. (II) complexes

    African Journals Online (AJOL)

    activities of Schiff base tin (II) complexes. Neelofar1 ... Conclusion: All synthesized Schiff bases and their Tin (II) complexes showed high antimicrobial and ...... Singh HL. Synthesis and characterization of tin (II) complexes of fluorinated Schiff bases derived from amino acids. Spectrochim Acta Part A: Molec Biomolec.

  3. Ln(3+)-doped nanoparticles for upconversion and magnetic resonance imaging: some critical notes on recent progress and some aspects to be considered.

    Science.gov (United States)

    van Veggel, Frank C J M; Dong, Cunhai; Johnson, Noah J J; Pichaandi, Jothirmayanantham

    2012-12-07

    In this feature article we will critically discuss the synthesis and characterisation aspects of Ln(3+)-doped nanoparticles (NPs) that show upconversion, upon 980 nm excitation. Upconversion is a non-linear process that converts two or more low-energy photons, often near-infrared photons, into one of higher energy, e.g. blue and 800 nm from Tm(3+) and green and red from Er(3+) or Ho(3+). Nearly all researchers use the absorption of 980 nm light by Yb(3+) as the sensitiser for the co-doped emissive Ln(3+) ions. The focus will be on LnF(3) and MLnF(4) (M = alkali metal) as the host matrix, because most progress has been made with these. In particular we will argue that a detailed understanding of how the dopant ions and the host Ln(3+) ions are distributed (in the core) and how (doped) shell growth occurs is not well understood. Moreover, their use as optical and magnetic resonance imaging contrast agents will be discussed. We will argue that deep-tissue imaging beyond 600 μm with retention of optical resolution, i.e. to see fine structure such as blood capillaries in brain tissues, has not yet been achieved. Three key parameters have been identified as impediments: (i) the low absorption efficiency of the Yb(3+) sensitiser, (ii) the low quantum yield of upconversion, and (iii) the long-lived excited states. On the other hand, there are very encouraging results that suggest that these nanoparticles could be developed into very potent magnetic resonance imaging (MRI) contrast agents.

  4. Inorganic pigments doped with tris(pyrazol-1-yl)borate lanthanide complexes: A photoluminescence study

    Energy Technology Data Exchange (ETDEWEB)

    Gheno, Giulia, E-mail: giulia.gheno@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Bortoluzzi, Marco; Ganzerla, Renzo [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Enrichi, Francesco [CIVEN, Coordinamento Interuniversitario Veneto per le Nanotecnologie, Via delle Industrie 5, 30175 Marghera, Venezia (Italy)

    2014-01-15

    The inorganic pigments malachite, Egyptian blue, Ercolano blue and chrome yellow have been doped with the neutral homoleptic Ln(III) complex Ln(Tp){sub 3} (Ln=Eu, Tb; Tp=hydrotris(pyrazol-1-yl)borate) in the presence of arabic gum or acrylic emulsion as binders, in order to obtain photoluminescent materials of interest for cultural heritage restoration. The doped pigments have shown emissions associated to f–f transitions in the visible range upon excitation with UV light. Thermal and UV-light ageings have been carried out. In all the cases the photoluminescent behaviour is maintained, but in the cases of acrylic-based paints emission spectra and lifetimes are strongly influenced by thermal treatments. The choice of binder and pigments influences the photoluminescent behaviour of the corresponding film paints. -- Highlights: • Inorganic pigments doped with photoluminescent lanthanide complexes. • Hydrotris(pyrazol-1-yl)borate (Tp) as antenna-ligand for Eu(III) and Tb(III). • Emission associated to f–f transitions upon excitation with UV light. • Photoluminescence of paints influenced by the choice of binder and pigments. • Photoluminescence after ageing depending upon the type of binder.

  5. Systematic Study of a Family of Butterfly-Like {M2Ln2} Molecular Magnets (M = Mg(II), Mn(III), Co(II), Ni(II), and Cu(II); Ln = Y(III), Gd(III), Tb(III), Dy(III), Ho(III), and Er(III)).

    Science.gov (United States)

    Moreno Pineda, Eufemio; Chilton, Nicholas F; Tuna, Floriana; Winpenny, Richard E P; McInnes, Eric J L

    2015-06-15

    A family of 3d-4f [M(II)2Ln(III)2(μ3-OH)2(O2C(t)Bu)10](2-) "butterflies" (where M(II) = Mg, Co, Ni, and Cu; Ln(III) = Y, Gd, Tb, Dy, Ho, and Er) and [Mn(III)2Ln(III)2(μ3-O)2(O2C(t)Bu)10](2-) molecules (where Ln(III) = Y, Gd, Tb, Dy, Ho, and Er) has been synthesized and characterized through single-crystal X-ray diffraction, SQUID magnetometry, and ab initio calculations. All dysprosium- and some erbium-containing tetramers showed frequency-dependent maxima in the out-of-phase component of the susceptibility associated with slow relaxation of magnetization, and hence, they are single-molecule magnets (SMMs). AC susceptibility measurements have shown that the SMM behavior is entirely intrinsic to the Dy and Er sites and the magnitude of the energy barrier is influenced by the interactions between the 4f and the 3d metal. A trend is observed between the strength of the 3d-4f exchange interaction between and the maximum observed in the χ″M(T).

  6. Structures and standard molar enthalpies of formation of a series of Ln(III)-Cu(II) heteronuclear compounds with pyrazine-2,3-dicarboxylic acid

    Science.gov (United States)

    Yang, Qi; Xie, Gang; Wei, Qing; Chen, Sanping; Gao, Shengli

    2014-07-01

    Fifteen lanthanide-copper heteronuclear compounds, formulated as [CuLn2(pzdc)4(H2O)6]·xH2O (1-6(x=2), 8(x=3), 9-10(x=4); [CuLn2(pzdc)4(H2O)4]·xH2O (7, 12-13, 15(x=4), 14(x=5), 11(x=8) (Ln(III)=La(1); Ce(2); Pr(3); Nd(4); Sm(5); Eu(6); Gd(7); Tb(8); Dy(9); Ho(10); Er(11); Tm(12); Yb(13); Lu(14); Y(15); H2pzdc (C6H4N2O4)=pyrazine-2,3-dicarboxylic acid) have been hydrothermally synthesized. All compounds were characterized by element analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analyses confirm that all compounds are isostructural and feature a 3D brick-like framework structure with {4.62}2{42.62.82}{63}2{65.8}2 topology. Using 1 mol cm-3 HCl(aq) as calorimetric solvent, with an isoperibol solution-reaction calorimeter, the standard molar enthalpies of formation of all compounds were determined by a designed thermochemical cycle. In addition, solid state luminescence properties of compounds 5, 6, 8 and 9 were studied in the solid state.

  7. Single crystals of LnFeAsO{sub 1-x}F{sub x} (Ln = La, Pr, Nd, Sm, Gd) and Ba{sub 1-x}Rb{sub x}Fe{sub 2}As{sub 2}: Growth, structure and superconducting properties

    Energy Technology Data Exchange (ETDEWEB)

    Karpinski, J., E-mail: karpinski@phys.ethz.c [Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich (Switzerland); Zhigadlo, N.D.; Katrych, S.; Bukowski, Z.; Moll, P. [Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich (Switzerland); Weyeneth, S.; Keller, H. [Physik-Institut der Universitaet Zuerich, 8057 Zuerich (Switzerland); Puzniak, R. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland); Tortello, M.; Daghero, D.; Gonnelli, R. [Dipartimento di Fisica, Politecnico di Torino, 10129 Torino (Italy); Maggio-Aprile, I. [DPMC-MaNEP, University of Geneva, Geneva (Switzerland); Fasano, Y. [DPMC-MaNEP, University of Geneva, Geneva (Switzerland); Low Temperatures Laboratory and Instituto Balseiro, Bariloche (Argentina); Fischer, O. [DPMC-MaNEP, University of Geneva, Geneva (Switzerland); Rogacki, K. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-950 Wroclaw, P.O. Box 1410 (Poland); Batlogg, B. [Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich (Switzerland)

    2009-05-01

    A review of our investigations on single crystals of LnFeAsO{sub 1-x}F{sub x} (Ln = La, Pr, Nd, Sm, Gd) and Ba{sub 1-x}Rb{sub x}Fe{sub 2}As{sub 2} is presented. A high-pressure technique has been applied for the growth of LnFeAsO{sub 1-x}F{sub x} crystals, while Ba{sub 1-x}Rb{sub x}Fe{sub 2}As{sub 2} crystals were grown using a quartz ampoule method. Single crystals were used for electrical transport, structure, magnetic torque and spectroscopic studies. Investigations of the crystal structure confirmed high structural perfection and show incomplete occupation of the (O, F) position in superconducting LnFeAsO{sub 1-x}F{sub x} crystals. Resistivity measurements on LnFeAsO{sub 1-x}F{sub x} crystals show a significant broadening of the transition in high magnetic fields, whereas the resistive transition in Ba{sub 1-x}Rb{sub x}Fe{sub 2}As{sub 2} simply shifts to lower temperature. The critical current density for both compounds is relatively high and exceeds 2 x 10{sup 9} A/m{sup 2} at 15 K in 7 T. The anisotropy of magnetic penetration depth, measured on LnFeAsO{sub 1-x}F{sub x} crystals by torque magnetometry is temperature dependent and apparently larger than the anisotropy of the upper critical field. Ba{sub 1-x}Rb{sub x}Fe{sub 2}As{sub 2} crystals are electronically significantly less anisotropic. Point-Contact Andreev-Reflection spectroscopy indicates the existence of two energy gaps in LnFeAsO{sub 1-x}F{sub x}. Scanning Tunneling Spectroscopy reveals in addition to a superconducting gap, also some feature at high energy (approx20 meV).

  8. Co-expression of α9β1 integrin and VEGF-D confers lymphatic metastatic ability to a human breast cancer cell line MDA-MB-468LN.

    Directory of Open Access Journals (Sweden)

    Mousumi Majumder

    Full Text Available INTRODUCTION AND OBJECTIVES: Lymphatic metastasis is a common occurrence in human breast cancer, mechanisms remaining poorly understood. MDA-MB-468LN (468LN, a variant of the MDA-MB-468GFP (468GFP human breast cancer cell line, produces extensive lymphatic metastasis in nude mice. 468LN cells differentially express α9β1 integrin, a receptor for lymphangiogenic factors VEGF-C/-D. We explored whether (1 differential production of VEGF-C/-D by 468LN cells provides an autocrine stimulus for cellular motility by interacting with α9β1 and a paracrine stimulus for lymphangiogenesis in vitro as measured with capillary-like tube formation by human lymphatic endothelial cells (HMVEC-dLy; (2 differential expression of α9 also promotes cellular motility/invasiveness by interacting with macrophage derived factors; (3 stable knock-down of VEGF-D or α9 in 468LN cells abrogates lymphangiogenesis and lymphatic metastasis in vivo in nude mice. RESULTS: A comparison of expression of cyclo-oxygenase (COX-2 (a VEGF-C/-D inducer, VEGF-C/-D and their receptors revealed little COX-2 expression by either cells. However, 468LN cells showed differential VEGF-D and α9β1 expression, VEGF-D secretion, proliferative, migratory/invasive capacities, latter functions being stimulated further with VEGF-D. The requirement of α9β1 for native and VEGF-D-stimulated proliferation, migration and Erk activation was demonstrated by treating with α9β1 blocking antibody or knock-down of α9. An autocrine role of VEGF-D in migration was shown by its impairment by silencing VEGF-D and restoration with VEGF-D. 468LN cells and their soluble products stimulated tube formation, migration/invasiveness of HMVEC-dLy cell in a VEGF-D dependent manner as indicated by the loss of stimulation by silencing VEGF-D in 468LN cells. Furthermore, 468LN cells showed α9-dependent stimulation of migration/invasiveness by macrophage products. Finally, capacity for intra-tumoral lymphangiogenesis and

  9. Rare-earth tricyanomelaminates [NH(4)]Ln[HC(6)N(9)](2)[H(2)O](7)H(2)O (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy): structural investigation, solid-state NMR spectroscopy, and photoluminescence.

    Science.gov (United States)

    Nag, Abanti; Lotsch, Bettina V; Schmedt Auf der Günne, Jörn; Oeckler, Oliver; Schmidt, Peter J; Schnick, Wolfgang

    2007-01-01

    The rare-earth tricyanomelaminates, [NH(4)]Ln[HC(6)N(9)](2)[H(2)O](7)xH(2)O (LnTCM; Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy), have been synthesized through ion-exchange reactions. They have been characterized by powder as well as single-crystal X-ray diffraction analysis, vibrational spectroscopy, and solid-state (1)H, (13)C, and (15)N MAS NMR spectroscopy. The X-ray powder pattern common to all nine rare-earth tricyanomelaminates LnTCM (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy) indicates that they are isostructural. The single-crystal X-ray diffraction pattern of LnTCM is indicative of non-merohedral twinning. The crystals are triclinic and separation of the twin domains as well as refinement of the structure were successfully carried out in the space group P1 for LaTCM (LaTCM; P1, Z=2, a=7.1014(14), b=13.194(3), c=13.803(3) A, alpha=90.11(3), beta=77.85(3), gamma=87.23(3) degrees , V=1262.8(4) A(3)). In the crystal structure, each Ln(3+) is surrounded by two nitrogen atoms from two crystallographically independent tricyanomelaminate moieties and seven oxygen atoms from crystal water molecules. The positions of all of the hydrogen atoms of the ammonium ions and water molecules could not be located from difference Fourier syntheses. The presence of [NH(4)](+) ions as well as two NH groups belonging to two crystallographically independent monoprotonated tricyanomelaminate moieties has only been confirmed by subjecting LaTCM to solid-state (1)H, (13)C, and (15)N{(1)H} cross-polarization (CP) MAS NMR and advanced CP experiments such as cross-polarization combined with polarization inversion (CPPI). The (1)H 2D double-quantum single-quantum homonuclear correlation (DQ SQ) spectrum and the (15)N{(1)H} 2D CP heteronuclear-correlation (HETCOR) spectrum have revealed the hydrogen-bonded (N--HN) dimer of monoprotonated tricyanomelaminate moieties as well as H-bonding through [NH(4)](+) ions and H(2)O molecules. The structures of the other eight rare-earth tricyanomelaminates (Ln

  10. Five novel lanthanide complexes with 2-chloroquinoline-4-carboxylic acid and 1,10-phenanthroline: Crystal structures, molecular spectra, thermal properties and bacteriostatic activities

    Science.gov (United States)

    Wang, Ye; Jin, Cheng-Wei; He, Shu-Mei; Ren, Ning; Zhang, Jian-Jun

    2016-12-01

    Five novel lanthanide complexes [Ln2(2-ClQL)6(phen)2(H2O)2]·2H2O (Ln = Pr(1), Sm(2), Eu(3), Ho(4), Er(5)); 2-ClQL: 2-chloroquinoline-4-carboxylate; phen: 1,10-phenanthroline; were synthesized by conventional solution method at room temperature and characterized via elemental analysis, powder x-ray diffraction, Infrared spectroscopy and Raman spectrometry. The results indicate that complexes 1-5 are isostructural, and each Ln3+ ion is eight-coordinated adopting a distorted square antiprismatic molecular geometry. Binuclear complex 1 are stitched together via hydrogen bonding interactions to form 1D chains, and further to form 2D sheets by the π-π interactions. Luminescence investigation reveals that complex 3 displays strong red emission. TG/DTG-FTIR, reveal the thermal decomposition processes and products of title complexes. The bacteriostatic activities of the complexes were evaluated against Candida albicans, Escherichia coli, and Staphylococcus aureus.

  11. Theoretical study of trivalent element complexes for the nuclear waste reprocessing; Etude theorique de complexes d'elements f trivalents pour le retraitement des dechets nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Petit, L

    2007-10-15

    Current energetic and environmental concerns have made the nuclear waste reprocessing to be a major issue in numerous countries. One avenue to treat nuclear spent fuel requires separating selectively trivalent minor actinides An (Am{sup 3+}, Cm{sup 3+}) from lanthanides Ln. In this regard, nitrogen extractants are under study. Their selectivity toward actinides is still unclear, but could be the result of enhanced covalency effects with trivalent minor actinides with respect to lanthanides (III). In this thesis, we have performed DFT calculations (Density Functional Theory) to study covalency effects within the actinide-ligand bond, following three main axes of research: advanced study of the nature of the chemical bonding, spectroscopic characterization of covalency, and preliminary tests of ab initio molecular dynamics for future calculations in solvent. Methods that are not regularly applied to trivalent actinides complexes have been used: topological methods, TDDFT, LDDFT, ab initio molecular dynamics. We have managed to show that the selectivity of the BTP ligand - the most effective An/Ln extractant to date - comes at least for a part from stronger covalency effects within the An-BTP bond with respect to the Ln-BTP bond, which has never been proved before. (author)

  12. Vliv nastavení protézy a protetického chodidla na posturální chování u osob po transtibiální amputaci The influence of prostheses and prosthetic foot alignment on postural behavior in transtibial amputees

    Directory of Open Access Journals (Sweden)

    Miroslav Janura

    2007-01-01

    Full Text Available Amputace dolní končetiny představuje aktuální kineziologický problém vzhledem k alteraci posturálního chování. Biomechanické a neurofyziologické změny následující po amputaci dolní končetiny jsou důsledkem mnoha kompenzačních a adaptačních mechanismů. Volba a nastavení jednotlivých protetických komponent u jedinců po transtibiální amputaci do značné míry determinuje charakter posturální stability a bipedální lokomoce. Cílem této studie bylo posoudit vliv změny nastavení protézy a protetického chodidla na posturální chování u osob s transtibiální amputací. U souboru 13 probandů (věk 56 ± 13 let, hmotnost 88,46 ± 12,3 kg bylo analyzováno posturální chování při pěti různých nastaveních protézy a protetického chodidla. Pro všechna nastavení jsme hodnotili symetrii rozložení tělesné hmotnosti a latenci posturálních reakcí za dynamických podmínek posturografi ckého testu Motor Control Test (NeuroCom® za současného snímání svalové aktivity pomocí povrchové elektromyografie (Noraxon. Z výsledků studie vyplývá, že změna nastavení protézy a protetického chodidla má vliv na svalovou aktivitu a na vybrané posturografi cké parametry. Za kineziologicky nejoptimálnější lze označit prodloužení protézy o 1 cm vzhledem k normálnímu nastavení, protože při tomto nastavení došlo k nejvíce symetrické aktivaci testovaných svalů. Při normálním nastavení byli transtibiálně amputovaní jedinci schopni nejefektivnější adaptability na vnější podnět, což se projevilo kontinuálním snižováním latence posturálních reakcí na rozdíl od jiných testovaných nastavení. Nejmenší asymetrie v rozložení tělesné hmotnosti při testu MCT byla při nastavení chodidla o 1 cm kratším, to se však neprojevilo na svalové aktivitě při tomto nastavení. Lower limb amputation presents a kinesiological problem. The type and alignment of each

  13. Complexity Plots

    KAUST Repository

    Thiyagalingam, Jeyarajan

    2013-06-01

    In this paper, we present a novel visualization technique for assisting the observation and analysis of algorithmic complexity. In comparison with conventional line graphs, this new technique is not sensitive to the units of measurement, allowing multivariate data series of different physical qualities (e.g., time, space and energy) to be juxtaposed together conveniently and consistently. It supports multivariate visualization as well as uncertainty visualization. It enables users to focus on algorithm categorization by complexity classes, while reducing visual impact caused by constants and algorithmic components that are insignificant to complexity analysis. It provides an effective means for observing the algorithmic complexity of programs with a mixture of algorithms and black-box software through visualization. Through two case studies, we demonstrate the effectiveness of complexity plots in complexity analysis in research, education and application. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.

  14. carbene complexes

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Reaction of oligomeric Cu(I) complexes [Cu{µ-S-C(=NR)(O–Ar–CH3)}]n with Lewis acids gave Cu(I) carbene complexes, which were characterized by 1H and 13C NMR spectroscopy. Cu(I) car- bene complexes could be directly generated from RNCS, Cu(I)–OAr and Lewis acids; this method can be used to ...

  15. Preparation, thermodynamic property and antimicrobial activity of some rare-earth (III) complexes with 3-bromo-5-iodobenzoic acid and 1,10-phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing-Yu [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Ren, Ning [Department of Chemistry, Handan College, Handan 056005 (China); Zhang, Jian-Jun, E-mail: jjzhang6@126.com [Testing and Analysis Center, Hebei Normal University, Shijiazhuang 050024 (China); College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Zhang, Cun-Ying [No.1 High School of Shijiazhuang, Shijiazhuang 050011 (China)

    2013-10-20

    Graphical abstract: Four new rare-earth complexes of general formula [Ln(3-Br-5-IBA){sub 3}phen]{sub 2} [Ln = Er (1), Tb (2), Dy (3) and Ho (4); 3-Br-5-IBA = 3-bromo-5-iodobenzoate; phen = 1,10-phenanthroline] were synthesized and characterized by elemental analysis, IR, UV and TG/DSC-FTIR technology. Heat capacities of the four complexes were measured by differential scanning calorimetry (DSC). The antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans were tested using disc diffusion method. - Highlights: • Four new complexes [Ln(3-Br-5-IBA){sub 3}phen]{sub 2} were synthesized and characterized. • The non-isothermal kinetics of the first stage for the complexes was studied. • The heat capacities of the complexes were measured by differential scanning calorimeter. • The antimicrobial activities for these complexes were tested. • The fluorescence properties of the complexes 2 and 3 were studied. - Abstract: Four new rare-earth complexes of general formula [Ln(3-Br-5-IBA){sub 3}phen]{sub 2} (Ln(III) = Er (1), Tb (2), Dy (3) and Ho (4); 3-Br-5-IBA = 3-bromo-5-iodobenzoate; phen = 1,10-phenanthroline) were synthesized by solution-precipitation method, and investigated using elemental analysis, infrared spectra, ultraviolet spectra and TG/DSC-FTIR technology. The non-isothermal kinetics of the first stage for the complexes was studied by using non-linear integral isoconversional method and double equal-double steps method. The heat capacities of the complexes were measured between 263.15 and 485.55 K by means of differential scanning calorimeter, and the values of the experimental heat capacities were fitted to a polynomial equation with the least-squares method. And the thermodynamic functions [H{sub T} − H{sub 298.15}], [S{sub T} − S{sub 298.15}] and [G{sub T} − G{sub 298.15}] were also derived based on the fitted polynomials and thermodynamic relationships with temperature interval of 10 K. Moreover, the

  16. Deformation Behavior and Evolution of Microstructure and Texture During Hot Compression of AISI 304LN Stainless Steel

    Science.gov (United States)

    Rout, Matruprasad; Biswas, Somjeet; Ranjan, Ravi; Pal, Surjya Kanta; Singh, Shiv Brat

    2017-12-01

    Deformation behavior of hot-rolled AISI 304 LN austenitic stainless steel was studied by hot axisymmetric compression tests at 1173 K, 1273 K, and 1373 K (900 °C, 1000 °C, and 1100 °C) at strain rates of 0.01, 0.1, and 1 s-1. The flow curves were examined to understand the deformation characteristics. The influence of Zener-Holloman parameter was analyzed using appropriate constitutive models. The activation energy for deformation was found to be 473 kJ/mol. Quantitative microstructural analysis was carried out using Electron backscattered diffraction. Compression at 1173 K (900 °C) at all true strain rates gave rise to partially dynamic recrystallized microstructure with strong α-fiber texture. The deformation texture is characterized by the formation of Brass component, and partial dynamic recrystallization (DRX) led to the development of Goss, S, and ube components. Necklace structure of small equiaxed recrystallized grains could be observed surrounding the large, elongated deformed grains. Compressions at 1273 K and 1373 K (1000 °C and 1100 °C) resulted in fully recrystallized microstructure consisting of mostly Σ3 and Σ9 coincidence site lattice high-angle boundaries. Compression at 1273 K (1000 °C) leads to the formation of low-intensity diffused α-fiber. DRX was confirmed by the presence of Goss, S, Cube, and rotated Cube components. Compression performed at 1373 K (1100 °C) resulted in nearly random texture with traces of α-fiber and prominent Cube/rotated Cube components. The microstructures of the 1173 K (900 °C)-compressed samples were partitioned using grain size and misorientation criteria to quantify DRX.

  17. LnPO 4 Nanoparticles Doped with Ac-225 and Sequestered Daughters for Targeted Alpha Therapy

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, Mark F. [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemistry and Univ. of Missouri Research Reactor; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Nuclear Safety and Isotopes Technology Division; Robertson, David [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemistry and Univ. of Missouri Research Reactor; Pevsner, Paul H. [Univ. of Missouri, Columbia, MO (United States). Dept. of Pathology; Univ. of Missouri, Columbia, MO (United States). Dept. of Electrical and Computer Engineering; Wall, Jonathan S. [Univ. of Tennessee, Knoxville, TN (United States). Graduate School of Medicine; Mirzadeh, Saed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Nuclear Safety and Isotopes Technology Division; Kennel, Stephen J. [Univ. of Tennessee, Knoxville, TN (United States). Graduate School of Medicine

    2014-02-01

    For targeted alpha therapy (TAT) with 225Ac, daughter radioisotopes from the parent emissions should be controlled. We report on a second-generation layered nanoparticle (NP) with improved daughter retention that can mediate TAT of lung tumor colonies. NPs of La3+, Gd3+, and 225Ac3+ ions were coated with additional layers of GdPO4 and then coated with gold via citrate reduction of NaAuCl4. MAb 201b, targeting thrombomodulin in lung endothelium, was added to a polyethylene glycol (dPEG)-COOH linker. Furthermore, we quantified the NPs:mAb ratio by labeling the mAb with 125I. NPs showed 30% injected dose/organ antibody-mediated uptake in the lung, which increased to 47% in mice pretreated with clodronate liposomes to reduce phagocytosis. Retention of daughter 213Bi in lung tissue was more than 70% at one hour and about 90% at 24 hours postinjection. Treatment of mice with lung-targeted 225Ac NP reduced EMT-6 lung colonies relative to cold antibody competition for targeting or phosphate-buffered saline injected controls. Finally, we show that LnPO4 NPs represent a viable solution to deliver the 225Ac as an in vivo α generator. The NPs successfully retain a large percentage of the daughter products without compromising the tumoricidal properties of the α-radiation.

  18. Creep Deformation and Rupture Behavior of Single- and Dual-Pass 316LN Stainless-Steel-Activated TIG Weld Joints

    Science.gov (United States)

    Vijayanand, V. D.; Vasudevan, M.; Ganesan, V.; Parameswaran, P.; Laha, K.; Bhaduri, A. K.

    2016-06-01

    Creep deformation and rupture behavior of single-pass and dual-pass 316LN stainless steel (SS) weld joints fabricated by an autogenous activated tungsten inert gas welding process have been assessed by performing metallography, hardness, and conventional and impression creep tests. The fusion zone of the single-pass joint consisted of columnar zones adjacent to base metals with a central equiaxed zone, which have been modified extensively by the thermal cycle of the second pass in the dual-pass joint. The equiaxed zone in the single-pass joint, as well as in the second pass of the dual-pass joint, displayed the lowest hardness in the joints. In the dual-pass joint, the equiaxed zone of the first pass had hardness comparable to the columnar zone. The hardness variations in the joints influenced the creep deformation. The equiaxed and columnar zone in the first pass of the dual-pass joint was more creep resistant than that of the second pass. Both joints possessed lower creep rupture life than the base metal. However, the creep rupture life of the dual-pass joint was about twofolds more than that of the single-pass joint. Creep failure in the single-pass joint occurred in the central equiaxed fusion zone, whereas creep cavitation that originated in the second pass was blocked at the weld pass interface. The additional interface and strength variation between two passes in the dual-pass joint provides more restraint to creep deformation and crack propagation in the fusion zone, resulting in an increase in the creep rupture life of the dual-pass joint over the single-pass joint. Furthermore, the differences in content, morphology, and distribution of delta ferrite in the fusion zone of the joints favors more creep cavitation resistance in the dual-pass joint over the single-pass joint with the enhancement of creep rupture life.

  19. Synthesis and Characterization of Lanthanide(III Nitrate Complexes with Terdentate ONO Donor Hydrazone Derived from 2-Benzimidazolyl Mercaptoaceto Hydrazide and o-Hydroxy Aromatic Aldehyde

    Directory of Open Access Journals (Sweden)

    Vinayak M. Naik

    2011-01-01

    Full Text Available A few eight coordinated complexes of lanthanide(III nitrate with 2-benzimidazolyl mercaptoaceto hydrazone ligand (LH2 with the general formula [Ln(LH2NO2]H2O (where Ln = La, Pr, Nd, Sm and Gd have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, UV-Visible, IR and 1H NMR spectral studies. The experimental data sustain stoichiometry of 1:2 (metal/ligand for the complexes. The spectral data shows that the ligand reacts in keto form and behaves as monobasic terdentate in nature. The nitrate appears to coordinate in the bidentate fashion to the metal ion. The thermal stabilities of the complexes have been studied by TGA and their kinetic parameters were calculated using Coats-Redfern and MKN methods. The antimicrobial activity studies have been under taken and results are discussed.

  20. Multicolour optical coding from a series of luminescent lanthanide complexes with a unique antenna.

    Science.gov (United States)

    Wartenberg, Nicolas; Raccurt, Olivier; Bourgeat-Lami, Elodie; Imbert, Daniel; Mazzanti, Marinella

    2013-03-04

    The bis-tetrazolate-pyridine ligand H(2)pytz sensitises efficiently the visible and/or near-IR luminescence emission of ten lanthanide cations (Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb). The Ln(III) complexes present sizeable quantum yields in both domains with a single excitation source. The wide range of possible colour combinations in water, organic solvents and the solid state makes the complexes very attractive for labelling and encoding. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The influence of carboxilate, phosphinate and seleninate groups on luminescent properties of lanthanides complexes

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Jorge H.S.K.; Formiga, André L.B.; Sigoli, Fernando A., E-mail: fsigoli@iqm.unicamp.br

    2014-10-15

    The lanthanides(III) complexes [Ln(bza){sub 3}(H{sub 2}O){sub n}]·mH{sub 2}O, [Ln(ppa){sub 3}(H{sub 2}O){sub n}]·mH{sub 2}O and [Ln(abse){sub 3}(H{sub 2}O){sub n}]·mH{sub 2}O where Ln=Eu{sup 3+}, Gd{sup 3+} or Tb{sup 3+} were synthesized using sodium benzoate (Nabza), sodium phenylseleninate (Naabse) and sodium phenylphosphinate (Nappa) in order to verify the influence on coordination modes and the luminescence parameters when the carbon is exchanged by phosphorus or selenium in those ligands. The complexes' stoichiometries were determined by lanthanide(III) titration, microanalysis and TGA. The coordination modes were determined as bidentate bridging and chelate by the FT-IR. The triplet state energies of the ligands were obtained by two different approaches giving a difference of about ∼2000 cm{sup −1} between them. The [Eu(abse){sub 3}(H{sub 2}O)] complex shows the higher degree of covalence which was verified by the centroid of {sup 5}D{sub 0}→{sup 7}F{sub 0} transition (17,248 cm{sup −1}). On the other hand the [Ln(abse){sub 3}(H{sub 2}O){sub n}]·mH{sub 2}O complexes have an inefficient antenna effect verified by the low values of absolute emission quantum yields. The [Ln(ppa){sub 3}(H{sub 2}O){sub n}]·mH{sub 2}O complexes have higher emission decay lifetime values among the complexes which is a result of the ability of this ligand to form coordination polymers avoiding water molecules in the first coordination sphere. The [Eu(ppa){sub 3}] complex has the highest point symmetry around europium(III) among the synthesized complexes, followed by the [Eu(bza){sub 3}(H{sub 2}O){sub 2}]·3/2(H{sub 2}O) and [Eu(abse){sub 3}(H{sub 2}O)] complexes where europium(III) show similar point symmetries. As one may expect, the triplet state energy position would change the transfer and/or back energy transfer rates from ligand to metal. The calculation of these rates show that the back energy transfer rates are more affected than the transfer ones by

  2. Computational Complexity

    Directory of Open Access Journals (Sweden)

    J. A. Tenreiro Machado

    2017-02-01

    Full Text Available Complex systems (CS involve many elements that interact at different scales in time and space. The challenges in modeling CS led to the development of novel computational tools with applications in a wide range of scientific areas. The computational problems posed by CS exhibit intrinsic difficulties that are a major concern in Computational Complexity Theory. [...

  3. Complex narratives

    NARCIS (Netherlands)

    Simons, J.

    2008-01-01

    This paper brings together narratology, game theory, and complexity theory to untangle the intricate nature of complex narratives in contemporary cinema. It interrogates the different terms - forking-path narratives, mind-game films, modular narratives, multiple-draft films, database narratives,

  4. Communication Complexity

    Indian Academy of Sciences (India)

    Jaikumar Radhakrishnan

    Communication complexity. Strategy I. Alice x ∈ {0, 1}n. ⇒. ⇐. Bob y ∈ {0, 1}n. Naive strategy. Alice sends x to Bob. Bob tells Alice if x = y. Cost. Requires n + 1 bits of communication. Jaikumar Radhakrishnan. Communication Complexity ...

  5. Complexity Theory

    Science.gov (United States)

    Lee, William H K.

    2016-01-01

    A complex system consists of many interacting parts, generates new collective behavior through self organization, and adaptively evolves through time. Many theories have been developed to study complex systems, including chaos, fractals, cellular automata, self organization, stochastic processes, turbulence, and genetic algorithms.

  6. Complex derivatives

    Science.gov (United States)

    Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph

    2013-03-01

    The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.

  7. Precursors for MOCVD and ALD of rare earth oxides-complexes of the early lanthanides with a donor-functionalized alkoxide ligand.

    Science.gov (United States)

    Aspinall, Helen C; Bickley, Jamie F; Gaskell, Jeffrey M; Jones, Anthony C; Labat, Gael; Chalker, Paul R; Williams, Paul A

    2007-07-23

    Complexes of the early lanthanides with the donor-functionalized alkoxide ligand mmp (Hmmp = HOCMe(2)CH(2)OMe, 1-methoxy-2-methylpropan-2-ol) are excellent precursors for Metal Organic Chemical Vapor Deposition (MOCVD) and Atomic Layer Deposition (ALD) of lanthanide oxides; however, their coordination chemistry, which is the subject of this paper, is rather complex. Precursors for MOCVD and ALD of lanthanide oxides are prepared by the reaction of [Ln{N(SiMe(3))(2)}(3)] with 3 equiv of the alcohol Hmmp in toluene in the presence of 1 equiv of tetraglyme and are indefinitely stable in solution. Reaction of [Ln{N(SiMe(3))(2)}(3)] with 3 equiv of Hmmp in the absence of stabilizing Lewis bases gives complex condensed products with empirical formula [{Ln(mmp)(3-n)}(2)O(n)]. These condensed products show poor volatility and are unsatisfactory precursors for MOCVD or ALD of oxides. The cluster complex [La(3)(mu(3),kappa(2)-mmp)(2)(mu(2),kappa(2)-mmp)(3)(mmp)(4)] has been prepared by careful reaction of [La{N(SiMe(3))(2)}(3)] with 4 equiv of Hmmp and has been characterized by single-crystal X-ray diffraction. Salt metathesis reactions using M(mmp) (M = Li or Na) are unreliable routes to [Ln(mmp)(3)]. Crystals of the heterometallic cluster complex [NaLa(3)(mu(3)-OH)(mu(3),kappa(2)-mmp)(2)(mu(2),kappa(2)-mmp)(4)(mmp)(3)] were isolated from the reaction of [La(NO(3))(3)(tetraglyme)] with 3 equiv of Na(mmp), and crystals of [Li(kappa(2)-Hmmp)Pr(mu(2),eta(2)-mmp)(4))LiCl] were isolated from the reaction of PrCl(3) with 3 equiv of Li(mmp); both of these complexes have been characterized by single-crystal X-ray diffraction.

  8. Dependence of the mechanism and regularities of energy transfer in binuclear lanthanide complexes in solutions on the nature of the anion and solvent

    Science.gov (United States)

    Sveshnikova, E. B.; Dudar', S. S.; Lanin, V. E.; Ermolaev, V. L.

    2002-10-01

    The effect of anions contained in solutions on the energy transfer from Tb(III) and Dy(III) ions to different Ln(III) ions is investigated in aqueous and alcohol solutions. It is shown that the regularities revealed in the energy transfer are completely determined by the ratio between the dissociation rate of the binuclear complex and the rate of energy transfer in it. The rate constant k t of energy transfer in solutions in which labile binuclear complexes of Ln(III) ions are linked through the strong acid anions Cl-, NO{3/-}, and HSO{4/-} depends on the nature of ions in the pairs. It is demonstrated that the energy transfer in all the systems predominantly occurs through the induction-resonance mechanism. The rate constants k t in aqueous solutions of weak (acetic, salicylic, and carbonic) acids also depend on the nature of ions interacting in pairs but do not correlate with the Förster overlap integral of the spectra. In labile binuclear complexes, the interaction between these ions proceeds by the exchange-resonance mechanism at a distance of ≈0.4 nm. It is established that the constants k t in alcohol solutions of Ln(III) ions are virtually independent of the nature of the pairs of the ions interacting through the acetate bridge. A comparison of the dissociation rate constants for Ln-anion complexes in alcohol solutions and the expected intracomplex rates of energy transfer in the binuclear complexes offers a satisfactory explanation of the obtained results and makes it possible to determine the association constants for binuclear lanthanide complexes in these solutions.

  9. Complex variables

    CERN Document Server

    Fisher, Stephen D

    1999-01-01

    The most important topics in the theory and application of complex variables receive a thorough, coherent treatment in this introductory text. Intended for undergraduates or graduate students in science, mathematics, and engineering, this volume features hundreds of solved examples, exercises, and applications designed to foster a complete understanding of complex variables as well as an appreciation of their mathematical beauty and elegance. Prerequisites are minimal; a three-semester course in calculus will suffice to prepare students for discussions of these topics: the complex plane, basic

  10. Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

    Science.gov (United States)

    Michaelovitch de Mahiques, Michel; Jörg Hanebuth, Till Jens; Hanae Nagai, Renata; Caruso Bícego, Marcia; Lopes Figueira, Rubens Cesar; Mello Sousa, Silvia Helena; Burone, Leticia; Franco-Fraguas, Paula; Taniguchi, Satie; Barbosa Salaroli, Alexandre; Pereira Dias, Gilberto; Menezes Prates, Denise; Fernandes Freitas, Maria Eugenia

    2017-03-01

    In this study, we use inorganic (metal) and organic (bulk and molecular) markers in sediment samples of the south-eastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply.Metal contents and especially the ln(Ti / Al) and ln(Fe / K) ratios make it possible to recognise the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K / Sc) and ln(K / Al) ratios used as proxies of illite-kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.

  11. Novel Cobalt(II) complexes containing N,N-di(2-picolyl)amine based ligands; Synthesis, characterization and application towards methyl methacrylate polymerisation

    Science.gov (United States)

    Ahn, Seoung Hyun; Choi, Sang-Il; Jung, Maeng Joon; Nayab, Saira; Lee, Hyosun

    2016-06-01

    The reaction of [CoCl2·6H2O] with N‧-substituted N,N-di(2-picolyl)amine ligands such as 1-cyclohexyl-N,N-bis(pyridin-2-ylmethyl)methanamine (LA), 2-methoxy-N,N-bis(pyridin-2-ylmethyl)ethan-1-amine (LB), and 3-methoxy-N,N-bis(pyridin-2-ylmethyl)propan-1-amine (LC), yielded [LnCoCl2] (Ln = LA, LB and LC), respectively. The Co(II) centre in [LnCoCl2] (Ln = LA, and LC) adopted distorted bipyramidal geometries through coordination of nitrogen atoms of di(2-picolyl)amine moiety to the Co(II) centre along with two chloro ligands. The 6-coordinated [LBCoCl2] showed a distorted octahedral geometry, achieved through coordination of the two pyridyl units, two chloro units, and bidentate coordination of nitrogen and oxygen in the N‧-methoxyethylamine to the Co(II) centre. [LCCoCl2] (6.70 × 104 gPMMA/molCo h) exhibited higher catalytic activity for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) compared to rest of Co(II) complexes. The catalytic activity was considered as a function of steric properties of ligand architecture and increased steric bulk around the metal centre resulted in the decrease catalytic activity. All Co(II) initiators yielded syndiotactic poly(methylmethacrylate) (PMMA).

  12. Carney Complex

    Science.gov (United States)

    ... at least one of the features listed. Major diagnostic features for Carney Complex Spotty skin pigmentation with ... called large cell calcifying Sertoli cell tumor (LCCST) Thyroid cancer Psammomatous melanotic schwannoma, meaning tumors that grow on ...

  13. Complex Covariance

    Directory of Open Access Journals (Sweden)

    Frieder Kleefeld

    2013-01-01

    Full Text Available According to some generalized correspondence principle the classical limit of a non-Hermitian quantum theory describing quantum degrees of freedom is expected to be the well known classical mechanics of classical degrees of freedom in the complex phase space, i.e., some phase space spanned by complex-valued space and momentum coordinates. As special relativity was developed by Einstein merely for real-valued space-time and four-momentum, we will try to understand how special relativity and covariance can be extended to complex-valued space-time and four-momentum. Our considerations will lead us not only to some unconventional derivation of Lorentz transformations for complex-valued velocities, but also to the non-Hermitian Klein-Gordon and Dirac equations, which are to lay the foundations of a non-Hermitian quantum theory.

  14. Antioxidant, tautomerism and antibacterial studies of Fe(III)-1,2,4-triazole based complexes

    Science.gov (United States)

    Kharadi, G. J.

    2013-06-01

    New Fe(III) complexes have been synthesized by the reactions of ferric nitrate with Schiff base derived from 3-substituted phenyl-4-amino-5-hydrazino-1,2,4-triazole and indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non-electrolytes. Elemental analyses suggest that the complexes have 1:1 stoichiometry of the type [FeLn(H2O)(OH)]·xH2O. Structural and spectroscopic properties have been studied on the basis of elemental analyses, infrared spectra, 1H and 13H NMR spectra, electronic spectra, magnetic measurements and FAB mass spectra. FT-IR, 1H and 13H NMR studies reveal that the ligand (Ln) exists in the tautomeric enol form in both the states with intramolecular hydrogen bonding. Magnetic moment and reflectance spectral studies reveal that an octahedral geometry has been assigned to all the prepared complexes. FRAP values indicate that all the compounds have a ferric reducing antioxidant power. The compounds 2 and 3 showed relatively high antioxidant activity while compound 1 and 4 shows poor antioxidant power. Also good antimicrobial activities of the complexes against Staphylococcus aureus, Bacillus subtilis, Serratia marcescens, Pseudomonas aeruginosa and Escherichia coli have been found compared to its free ligands.

  15. Chomutovsko: Sociální vyloučení s důrazem na problematiku bydlení

    OpenAIRE

    Beková, Anna

    2014-01-01

    Rigorous work deals with description of problematics of social exclusion in relation to housing. First chapters derive mainly from literature and international documents. They are dealing with different views on the right to housing, social exclusion and socially excluded areas. There are also discussed basic legislation, in which are contained benefits for housing. These are Act no. 117/1995 Sb., of State Social Support (o státní sociální podpoře) and Act no. 111/2006 Sb., of assistance in m...

  16. Determinación del coeficiente piroeléctrico del sistema ferroeléctrico cerámico de Pb0.88Ln0.08Ti0.98Mn0.02O3 (Ln=La, Sm, Eu y su aplicación en detectores de infrarrojo

    Directory of Open Access Journals (Sweden)

    Suaste-Gómez, E.

    2004-12-01

    Full Text Available In this work the dielectric and pyroelectric characteristics of the ferroelectric ceramic system of Pb0.88(Ln0.08Ti0.98Mn0.02O3 (Ln = La, Sm, Eu are studied in order to determine its usefulness as infrared dectectors. Dielectric constant and pyroelectric coefficient of the ceramics were determined. This material with perovskite structure presented a phase transition from tetragonal to cubic on the heating process, besides of presenting high values of dielectric constant. Values of figure of merit for infrared detection Rv=pi/εr were calculated. The results were compared with other materials used as infrared detectors.En este trabajo se estudian las características dieléctricas y piroeléctricas del sistema ferroléctrico cerámico de Pb0.88(Ln0.08Ti0.98 Mn0.02O3 (Ln = La, Sm, Eu para determinar su utilidad como detectores de infrarrojo. Se determinó la constante dieléctrica y el coeficiente piroeléctrico de las cerámicas. Este material con estructura de perovskita presentó una transición de fase tetragonal a cúbica en el proceso de calentamiento, además de presentar altos valores de la constante dieléctrica. Se obtuvieron valores de la figura de mérito para detección infrarroja Rv=pi/εr Los resultados se compararon con otros materiales usados como detectores de infrarrojo.

  17. pH dependent photophysical studies of new europium and terbium complexes of tripodal ligand: Experimental and semiempirical approach

    Energy Technology Data Exchange (ETDEWEB)

    Akbar, Rifat [Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal, Punjab 148106 (India); Baral, Minati [Department of Chemistry, National Institute of Technology Kurukshetra, Haryana 136119 (India); Kanungo, B K, E-mail: b.kanungo@gmail.com [Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal, Punjab 148106 (India)

    2015-11-15

    The photophysical properties of adduct of a novel nonadentate tripodal ligand, 5,5′-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1, 3-diyl)bis(azanediyl)bis(methylene diquinolin-8-ol, (TAME5OX), with Eu{sup 3+} and Tb{sup 3+} metal ions have been probed for photonics applications. The absorption spectroscopy of these complexes show remarkable spectral changes due to characteristic lanthanide transitions, which support the use of TAME5OX as a sensitive optical pH based sensor to detect Ln{sup 3+} metal ions in biological systems. In addition, these complexes have also been shown to exhibit strong green fluorescence allowing simultaneous sensing within the visible region under physiological pH in competitive medium for both Eu{sup 3+} and Tb{sup 3+} ions. The intense fluorescence from these compounds were revealed to intermittently get quenched under acidic as well as basic conditions due to the photoinduced intramolecular electron transfer from excited 8-hydroxyquinoline (8-HQ) moiety to metal ion, just an opposite process. This renders these compounds the OFF–ON–OFF type of pH-dependent fluorescent sensor. The thermodynamic stability and aqueous coordination chemistry of the chelator with the said lanthanide ions have also been probed by potentiometric, UV–visible and fluorescence spectrophotometric method. TAME5OX has been found to form two protonated complexes [Ln(H{sub 5}L)]{sup 5+} and [Ln(H{sub 4}L)]{sup 4+} below pH 2.5 with both metal ions, which consecutively deprotonates through one proton process with rise of pH. The formation constants (log β{sub 11n}) of neutral complexes have been determined to be 33.51 and 32.16 with pLn (pLn=−log[Ln{sup 3+}]) values of 16.14 and 19.48 for Eu{sup 3+} and Tb{sup 3+} ions, respectively, calculated at pH 7.4, indicating TAME5OX is a good lanthanide synthetic chelator. The emission lifetimes of the Eu{sup 3+} and Tb{sup 3+} complexes recorded in D{sub 2}O and H{sub 2}O suggest the presence

  18. N6-Benzyladenosine Derivatives as Novel N-Donor Ligands of Platinum(II Dichlorido Complexes

    Directory of Open Access Journals (Sweden)

    Ján Vančo

    2013-06-01

    Full Text Available The platinum(II complexes trans-[PtCl2(Ln2]∙xSolv 1–13 (Solv = H2O or CH3OH, involving N6-benzyladenosine-based N-donor ligands, were synthesized; Ln stands for N6-(2-methoxybenzyladenosine (L1, involved in complex 1, N6-(4-methoxy-benzyladenosine (L2, 2, N6-(2-chlorobenzyladenosine (L3, 3, N6-(4-chlorobenzyl-adenosine (L4, 4, N6-(2-hydroxybenzyladenosine (L5, 5, N6-(3-hydroxybenzyl-adenosine (L6, 6, N6-(2-hydroxy-3-methoxybenzyladenosine (L7, 7, N6-(4-fluoro-benzyladenosine (L8, 8, N6-(4-methylbenzyladenosine (L9, 9, 2-chloro-N6-(3-hydroxy-benzyladenosine (L10, 10, 2-chloro-N6-(4-hydroxybenzyladenosine (L11, 11, 2-chloro-N6-(2-hydroxy-3-methoxybenzyladenosine (L12, 12 and 2-chloro-N6-(2-hydroxy-5-methylbenzyladenosine (L13, 13. The compounds were characterized by elemental analysis, mass spectrometry, IR and multinuclear (1H-, 13C-, 195Pt- and 15N- and two-dimensional NMR spectroscopy, which proved the N7-coordination mode of the appropriate N6-benzyladenosine derivative and trans-geometry of the title complexes. The complexes 1–13 were found to be non-toxic in vitro against two selected human cancer cell lines (HOS and MCF7; with IC50 > 50.0 µM. However, they were found (by ESI-MS study to be able to interact with the physiological levels of the sulfur-containing biogenic biomolecule L-methionine by a relatively simple 1:1 exchange mechanism (one Ln molecule was replaced by one L-methionine molecule, thus forming a mixed-nitrogen/sulfur-ligand dichlorido-platinum(II coordination species.

  19. Revealing and tuning the core, structure, properties and function of polymer micelles with lanthanide-coordination complexes.

    Science.gov (United States)

    Wang, Junyou; Groeneveld, Andrea; Oikonomou, Maria; Prusova, Alena; Van As, Henk; van Lent, Jan W M; Velders, Aldrik H

    2016-01-07

    Controlling self-assembly processes is of great interest in various fields where multifunctional and tunable materials are designed. We here present the versatility of lanthanide-complex-based micelles (Ln-C3Ms) with tunable coordination structures and corresponding functions (e.g. luminescence and magnetic relaxation enhancement). Micelles are prepared by charge-driven self-assembly of a polycationic-neutral diblock copolymer and anionic coordination complexes formed by Ln(III) ions and the bis-ligand L2EO4, which contains two dipicolinic acid (DPA) ligand groups (L) connected by a tetra-ethylene oxide spacer (EO4). By varying the DPA/Ln ratio, micelles are obtained with similar size but with different stability, different aggregation numbers and different oligomeric and polymeric lanthanide(III) coordination structures in the core. Electron microscopy, light scattering, luminescence spectroscopy and magnetic resonance relaxation experiments provide an unprecedented detailed insight into the core structures of such micelles. Concomitantly, the self-assembly is controlled such that tunable luminescence or magnetic relaxation with Eu-C3Ms, respectively, Gd-C3Ms is achieved, showing potential for applications, e.g. as contrast agents in (pre)clinical imaging. Considering the various lanthanide(III) ions have unique electron configurations with specific physical chemical properties, yet very similar coordination chemistry, the generality of the current coordination-structure based micellar design shows great promise for development of new materials such as, e.g., hypermodal agents.

  20. Synthesis and structure of a new family of 3d-4f heterometallic compounds Rb7LnFe6O2(PO4)8 (Ln=Sm, Eu, Gd, Dy): Magnetic properties of the Sm-, Gd-, Dy-derivatives

    Science.gov (United States)

    Sanjeewa, Liurukara D.; Palmer West, J.; Hwu, Shiou-Jyh

    2012-08-01

    A new family of mixed lanthanide(III) and iron(III) oxo-phosphate phases, Rb7LnFe6O2(PO4)8 (Ln=Sm 1, Eu 2, Gd 3, Dy 4), was isolated by using a high-temperature, solid-state method in molten-salt media. The X-ray single-crystal structure analysis shows that these isomorphic derivatives crystallize in a triclinic space group P-1 (no. 2); Z=1. The 3-D framework of these 3d-4f oxo-phosphates are comprised of LnO6 octahedral, FeO5 trigonal bipyramidal (tbp), and μ3-oxo [Fe4O18] tetrameric units interconnected through PO4 tetrahedra. The preliminary results of the temperature-dependent magnetic susceptibility measurements for selected compounds (1, 3, 4) reveal antiferromagnetic-like behavior. 1 shows a weak antiferromagnetric ordering at TN=˜7 K while others show little evidence of long-range magnetic order down to 2 K. All three compounds have measured magnetic moments significantly smaller than the expected values.

  1. TEMPERATURE TRENDS OF THE PERMITTIVITY IN COMPLEX OXIDES OF RARE-EARTH ELEMENTS WITH PEROVSKITE-TYPE STRUCTURE

    Directory of Open Access Journals (Sweden)

    A.G.Belous

    2003-01-01

    Full Text Available Ceramic materials based on complex oxides with both the perovskite structure (Ln2/3Nb2O6 and the structure of tetragonal tungsten bronze (Ba6-xLn8+2x/3Ti18O54 have been investigated over a wide frequency and temperature ranges. The results obtained for certain structures denote the presence of the temperature anomalies of dielectric parameters (ε, tanδ. These anomalies occur over the wide frequency range including submilimeter (SMM wavelength range, and are related neither with the processing peculiarities nor with the presence of the phase transitions. Temperature behavior of the permittivity has been considered in terms of the polarization mechanism based on the elastic-strain lattice oscillations. It has been assumed that the observed anomalies could be ascribed to a superposition of harmonic and anharmonic contribution to lattice oscillations that determines τε sign and magnitude.

  2. Employment of methyl 2-pyridyl ketone oxime in 3d/4f-metal chemistry: dinuclear nickel(II)/lanthanide(III) species and complexes containing the metals in separate ions.

    Science.gov (United States)

    Polyzou, Christina D; Nikolaou, Helen; Papatriantafyllopoulou, Constantina; Psycharis, Vassilis; Terzis, Aris; Raptopoulou, Catherine P; Escuer, Albert; Perlepes, Spyros P

    2012-11-28

    The use of methyl 2-pyridyl ketone oxime (mpkoH) for the synthesis of Ni(II)/Ln(III) (Ln = lanthanide) complexes, using "one-pot" reactions in the absence of an external base, is described. Depending on the reaction and crystallization conditions employed, two families of complexes have been obtained. The first family consists of true heterometallic species and involves complexes [NiLn(mpko)(3)(mpkoH)(3)](ClO(4))(2), where Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er. The second family contains the pseudo heterometallic complexes [Ni(mpkoH)(3)](2)[Ln(NO(3))(6)](ClO(4)), where Ln = La, Ce, Pr, Nd and Sm. The crystal structures of [NiCe(mpko)(3)(mpkoH)(3)](ClO(4))(2) (1), [NiDy(mpko)(3)(mpkoH)(3)](ClO(4))(2) (8) and [Ni(mpkoH)(3)](2)[La(NO(3))(6)](ClO(4)) (11) have been determined by single-crystal, X-ray crystallography. Complexes 1·1.2MeOH·0.6H(2)O and 8·1.2MeOH·0.6H(2)O crystallise in the monoclinic space group P2(1)/a and are isomorphous; there are two crystallographically independent cations in the unit cell, but their interatomic distances and angles differ little. The Ni(II) and Ln(III) ions are bridged by three oximate groups belonging to the η(1):η(1):η(1):μ mpko(-) ligands. The Ni(II) centre is octahedrally coordinated by the six nitrogen atoms of the mpko(-) ligands in a facial arrangement. The Ln(III) centre is bound to an (O(oximate))(3)N(6) set of donor atoms, the nitrogen atoms belonging to the three N,N'-bidentate chelating mpkoH ligands. The stereochemistry of the Ln(III) atoms has been evaluated by means of continuous shape measures (CShM). The two crystallographically independent Ce(III) atoms in 1 have tricapped trigonal prismatic and capped square antiprismatic coordination geometries, while the polyhedra of the Dy(III) atoms in 8 are both close to a tricapped trigonal prism. The octahedral Ni(II) atoms in 11 are both facially bound to a N(6) set of donor atoms from three N,N'-bidentate chelating mpkoH ligands, while the 12-coordinate

  3. Complex chimerism

    Science.gov (United States)

    Ma, Kimberly K.; Petroff, Margaret G.; Coscia, Lisa A.; Armenti, Vincent T.; Adams Waldorf, Kristina M.

    2013-01-01

    Thousands of women with organ transplantation have undergone successful pregnancies, however little is known about how the profound immunologic changes associated with pregnancy might influence tolerance or rejection of the allograft. Pregnant women with a solid organ transplant are complex chimeras with multiple foreign cell populations from the donor organ, fetus, and mother of the pregnant woman. We consider the impact of complex chimerism and pregnancy-associated immunologic changes on tolerance of the allograft both during pregnancy and the postpartum period. Mechanisms of allograft tolerance are likely dynamic during pregnancy and affected by the influx of fetal microchimeric cells, HLA relationships (between the fetus, pregnant woman and/or donor), peripheral T cell tolerance to fetal cells, and fetal minor histocompatibility antigens. Further research is necessary to understand the complex immunology during pregnancy and the postpartum period of women with a solid organ transplant. PMID:23974274

  4. Complex analysis

    CERN Document Server

    Freitag, Eberhard

    2005-01-01

    The guiding principle of this presentation of ``Classical Complex Analysis'' is to proceed as quickly as possible to the central results while using a small number of notions and concepts from other fields. Thus the prerequisites for understanding this book are minimal; only elementary facts of calculus and algebra are required. The first four chapters cover the essential core of complex analysis: - differentiation in C (including elementary facts about conformal mappings) - integration in C (including complex line integrals, Cauchy's Integral Theorem, and the Integral Formulas) - sequences and series of analytic functions, (isolated) singularities, Laurent series, calculus of residues - construction of analytic functions: the gamma function, Weierstrass' Factorization Theorem, Mittag-Leffler Partial Fraction Decomposition, and -as a particular highlight- the Riemann Mapping Theorem, which characterizes the simply connected domains in C. Further topics included are: - the theory of elliptic functions based on...

  5. Stability of in 111In-ligand Complexes Studied by TDPAC

    Science.gov (United States)

    Shpinkova, L. G.; Kulakov, V. N.; Sorokin, A. A.; Ryasny, G. K.; Komissarova, B. A.; Nikitin, S. M.

    1998-07-01

    The TDPAC technique has been applied to study the stability of 111In complexes with NTA and DTPA in solutions with different concentrations of stable In at pH = 7. A sample of In-DTPA complexes attached to microspheres of albumin (MSA) has been measured at temperatures of 293 and 130 K. The results show that the products formed after 111ln → 111Cd decay and following Auger-effect are determined by the stability of In (Cd)-complexes with organic ligands. The daughter Cd behaviour depends on the In: ligand mole ratio, from 1: ∞ to 1:1. The possibility of Cd-ligand complex destruction and following Cd rechelating is discussed. The results indicate that the rechelating probability correlates with the stability of the parent and daughter complexes.

  6. Complex Analysis

    CERN Document Server

    Stein, Elias M

    2009-01-01

    With this second volume, we enter the intriguing world of complex analysis. From the first theorems on, the elegance and sweep of the results is evident. The starting point is the simple idea of extending a function initially given for real values of the argument to one that is defined when the argument is complex. From there, one proceeds to the main properties of holomorphic functions, whose proofs are generally short and quite illuminating: the Cauchy theorems, residues, analytic continuation, the argument principle.With this background, the reader is ready to learn a wealth of additional m

  7. Complex manifolds

    CERN Document Server

    Morrow, James

    2006-01-01

    This book, a revision and organization of lectures given by Kodaira at Stanford University in 1965-66, is an excellent, well-written introduction to the study of abstract complex (analytic) manifolds-a subject that began in the late 1940's and early 1950's. It is largely self-contained, except for some standard results about elliptic partial differential equations, for which complete references are given. -D. C. Spencer, MathSciNet The book under review is the faithful reprint of the original edition of one of the most influential textbooks in modern complex analysis and geometry. The classic

  8. Katetrová ablace pro fibrilaci síní a spektrální analýza variability srdeční frekvence Catheter ablation for atrial fibrillation and spectral analysis of heart rate variability

    Directory of Open Access Journals (Sweden)

    Esseid Gaddur

    2005-02-01

    Full Text Available Cílem studie bylo zkoumání vlivu katetrové ablace na parametry spektrální analýzy (SA variability srdeční frekvence (HRV. Krátkodobý záznam SA HRV byl snímán u skupiny 22 pacientů s paroxysmální fibrilací síní (FS ve věku 53,69 ± 11,95 let (20 mužů a 2 ženy, u kterých byla provedena cirkumferenční katetrová ablace (KA. Měření probíhalo ve třech polohách (leh-stoj-leh, za standardizovaných podmínek, ráno před KA a jeden den po KA. K vyhodnocení výsledků byla použita jak standardní, tak nová metodika hodnocení SA HRV pomocí komplexních ukazatelů. Po KA pro FS došlo ke zvýšení srdeční frekvence (SF a zhoršení většiny jednotlivých i komplexních ukazatelů. Tento nález svědčí o redukci aktivity obou větví autonomního nervového systému. Protože snížení aktivity vagu je výraznější, posouvá se sympatovagová rovnováha mírně směrem k sympatiku. The results of a short term recording of spectral analysis (SA of heart rate variability (HRV in 22 patients with paroxysmal atrial fibrillation (aged 53.69 ± 11.95; 20 male and 2 female in whom circumferential catheter ablation (CA was done are presented in this article. Measurement was done in the morning before CA and one day after CA. A standard orthoclinostatic test in three positions (supine–standing–supine was used. The influence of catheter ablation on SA HRV was identified by standard and complex parameters (Stejskal, Šlachta, Elfmark, Salinger, &Gaul-Aláčová, 2002. After CA, heart rate increased and almost all individual and complex indexes decreased. This finding gives evidence of reduction of activity in both branches of the autonomous nervous system. Vagal activity reduction was larger, so the sympathovagal balance shifts towards sympathicus.

  9. Magnetic properties of monoclinic lanthanide metaborates, Ln(BO2)3, Ln  =  Pr, Nd, Gd, Tb

    Science.gov (United States)

    Mukherjee, P.; Suard, E.; Dutton, S. E.

    2017-10-01

    The bulk magnetic properties of the lanthanide metaborates, Ln(BO2)3, Ln  =  Pr, Nd, Gd, Tb are studied using magnetic susceptibility, heat capacity and isothermal magnetisation measurements. They are found to crystallise in a monoclinic structure containing chains of magnetic Ln 3+ and could therefore exhibit features of low-dimensional magnetism and frustration. Pr(BO2)3 is found to have a non-magnetic singlet ground state. No magnetic ordering is observed down to 0.4 K for Nd(BO2)3. Gd(BO2)3 exhibits a sharp magnetic transition at 1.1 K, corresponding to 3D magnetic ordering. Tb(BO2)3 shows two magnetic ordering features at 1.05 K and 1.95 K. A magnetisation plateau at a third of the saturation magnetisation is seen at 2 K for both Nd(BO2)3 and Tb(BO2)3, which persists in an applied field of 14 T. This is proposed to be a signature of quasi 1D behaviour in Nd(BO2)3 and Tb(BO2)3.

  10. Synthesis of Multicolor Core/Shell NaLuF4:Yb3+/Ln3+@CaF2 Upconversion Nanocrystals

    Science.gov (United States)

    Li, Hui; Hao, Shuwei; Yang, Chunhui; Chen, Guanying

    2017-01-01

    The ability to synthesize high-quality hierarchical core/shell nanocrystals from an efficient host lattice is important to realize efficacious photon upconversion for applications ranging from bioimaging to solar cells. Here, we describe a strategy to fabricate multicolor core @ shell α-NaLuF4:Yb3+/Ln3+@CaF2 (Ln = Er, Ho, Tm) upconversion nanocrystals (UCNCs) based on the newly established host lattice of sodium lutetium fluoride (NaLuF4). We exploited the liquid-solid-solution method to synthesize the NaLuF4 core of pure cubic phase and the thermal decomposition approach to expitaxially grow the calcium fluoride (CaF2) shell onto the core UCNCs, yielding cubic core/shell nanocrystals with a size of 15.6 ± 1.2 nm (the core ~9 ± 0.9 nm, the shell ~3.3 ± 0.3 nm). We showed that those core/shell UCNCs could emit activator-defined multicolor emissions up to about 772 times more efficient than the core nanocrystals due to effective suppression of surface-related quenching effects. Our results provide a new paradigm on heterogeneous core/shell structure for enhanced multicolor upconversion photoluminescence from colloidal nanocrystals. PMID:28336867

  11. Di-Ethylhexylphthalate (DEHP Modulates Cell Invasion, Migration and Anchorage Independent Growth through Targeting S100P in LN-229 Glioblastoma Cells

    Directory of Open Access Journals (Sweden)

    Jennifer Nicole Sims

    2014-05-01

    Full Text Available Glioblastoma multiforme (GBM is the most aggressive brain cancer with a median survival of 1–2 years. The treatment of GBM includes surgical resection, radiation and chemotherapy, which minimally extends survival. This poor prognosis necessitates the identification of novel molecular targets associated with glioblastoma. S100P is associated with drug resistance, metastasis, and poor clinical outcomes in many malignancies. The functional role of S100P in glioblastoma has not been fully investigated. In this study, we examined the role of S100P mediating the effects of the environmental contaminant, DEHP, in glioblastoma cells (LN-229 by assessing cell proliferation, apoptosis, anchorage independent growth, cell migration and invasion following DEHP exposure. Silencing S100P and DEHP treatment inhibited LN-229 glioblastoma cell proliferation and induced apoptosis. Anchorage independent growth study revealed significantly decreased colony formation in shS100P cells. We also observed reduced cell migration in cells treated with DEHP following S100P knockdown. Similar results were observed in spheroid formation and expansion. This study is the first to demonstrate the effects of DEHP on glioblastoma cells, and implicates S100P as a potential therapeutic target that may be useful as a drug response biomarker.

  12. Modul digitálního signálového procesoru pro ruční RFID čtečku

    OpenAIRE

    Benetka, Miroslav

    2008-01-01

    Tato diplomová práce se zabývá návrhem a realizací modulu digitálního signálového procesoru pro ruční RFID čtečku pracující v UHF pásmu. Je zde zvoleno řešení, které využívá speciální integrovaný obvod EM4298 pro zpracování RFID signálů. Modul je řízen mikrokontrolérem ATmega32L, který přes sběrnici USB komunikuje s PC. Pomocí obslužného programu je prováděno veškeré nastavování obvodu EM4298 a také jsou zde zpracovávána přijatá identifikační data získaná z odpovídačů. Zdrojové kódy mikrokont...

  13. Near-infrared luminescence and RNA cleavage ability of lanthanide Schiff base complexes derived from N,N'-bis(3-methoxysalicylidene)ethylene-1,2-diamine ligands.

    Science.gov (United States)

    Kaczmarek, Anna M; Porebski, Piotr W Alvarez; Mortier, Tineke; Lynen, Frederic; Van Deun, Rik; Van Hecke, Kristof

    2016-10-01

    A complete series of lanthanide Schiff base salen-type complexes were prepared with trivalent lanthanide ions (Ln3+) and the N,N'-bis-(3-methoxysalicylidene)ethylene-1,2-diamine ligand (Ln3+=La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+). Three unique crystal structures of La3+ and Pr3+N,N'-bis-(3-methoxysalicylidene)ethylene-1,2-diamine complexes, with the La3+ complex prepared in two different synthetic approaches, are reported, namely a dimeric [La(H2L)(NO3)3]2 (H2L=N,N'-bis-(3-methoxysalicylidene)ethylene-1,2-diamine) complex, an asymmetric two-centered [La2(H2L)2(NO3)6] complex and a discrete mononuclear [Pr(H2L)(NO3)2(H2O)2] complex. For Nd3+ and Sm3+, an isotypic mononuclear [Nd(H2L)(NO3)3] and 1D polymeric [Sm(H2L)(NO3)3(MeOH)]n structure was obtained, respectively. The whole series of complexes was tested for their ability to cleave the 20-mer RNA oligonucleotide 5'-AGC-GAU-AAG-AUU-CAU-AUA-UC-3'. Additionally three complexes (Ln3+=Nd3+, Sm3+, Ho3+) were tested for the cleavage of the 12-mer RNA oligonucleotide 5'-GCA-CCC-UGU-CAG-3'. A detailed luminescence study was additionally carried out and revealed that the Eu3+ complex emitted bright red light upon excitation at both 285.8nm and 394.4nm. The Nd3+, Er3+, and Yb3+ complexes showed strong emission in the near-infrared region after excitation at 380nm. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Managing Complexity

    DEFF Research Database (Denmark)

    Maylath, Bruce; Vandepitte, Sonia; Minacori, Patricia

    2013-01-01

    This article discusses the largest and most complex international learning-by-doing project to date- a project involving translation from Danish and Dutch into English and editing into American English alongside a project involving writing, usability testing, and translation from English into Dutch...

  15. phenanthroline complexes

    Indian Academy of Sciences (India)

    structural analyses. Mass spectral studies of the complexes indicate both the compounds to produce identical cationic species viz., [Co(phen)2Cl2]+ in methanol solution. ... Cobalt(III); X-ray structure; Catecholase activity; DNA cleavage; Anti-cancer activity. 1. ..... necrotic as judged by the staining, nuclear morphology.

  16. Lecithin Complex

    African Journals Online (AJOL)

    China). Lecithin from soya bean was a product of. Sangon (Shanghai, China). Methanol of HPLC grade was purchased from Tedia (USA). Other chemicals used were of analytical grade. Preparation of polydatin-lecithin complex. Polydatin (200 mg) and lecithin (400 mg) were dissolved in 50 mL of tetrahydrofuran and stirred.

  17. Complex Criminality

    NARCIS (Netherlands)

    Bruin, D.; Abels, D.; van der Wilt, H.

    2016-01-01

    This book presents a collection of essays on the wide diversity of meanings of complex criminality. These essays were written to commemorate a national gathering of PhD candidates, from criminal law departments of different universities, at the University of Amsterdam on the 6th of June 2014.

  18. Complex Networks

    CERN Document Server

    Evsukoff, Alexandre; González, Marta

    2013-01-01

    In the last decade we have seen the emergence of a new inter-disciplinary field focusing on the understanding of networks which are dynamic, large, open, and have a structure sometimes called random-biased. The field of Complex Networks is helping us better understand many complex phenomena such as the spread of  deseases, protein interactions, social relationships, to name but a few. Studies in Complex Networks are gaining attention due to some major scientific breakthroughs proposed by network scientists helping us understand and model interactions contained in large datasets. In fact, if we could point to one event leading to the widespread use of complex network analysis is the availability of online databases. Theories of Random Graphs from Erdös and Rényi from the late 1950s led us to believe that most networks had random characteristics. The work on large online datasets told us otherwise. Starting with the work of Barabási and Albert as well as Watts and Strogatz in the late 1990s, we now know th...

  19. peroxo complexes

    Indian Academy of Sciences (India)

    Administrator

    The investigation of dioxygen binding and activation in dinuclear iron complexes has attracted recent interest because of the presence of carboxylate bridged dinuclear iron sites in several biologically important proteins, such as the R2 protein of ribonucleotide reductase, the hydroxylase component of methane ...

  20. carbohydrate complexes

    Indian Academy of Sciences (India)

    ferrocene-carbohydrate conjugates38,39 have lead to the design and study of the cytotoxic activity of metal com- plexes containing carbohydrate ligands. Hence, here we present the detailed synthesis and characteriza- tion of the carbohydrate triazole ligands and their Pd- complexes together with the crystal structures of ...

  1. Ntem Complex

    African Journals Online (AJOL)

    Zena

    New ages were obtained from charnockites and tonalites collected in the So'o Group in the Ntem Complex. The rocks were analyzed for their petrography, tectonics and 207Pb/206Pb zircon minimum ages of their zircons as well as .... Owona, Department of Earth Sciences, Faculty of Science, University of Douala, P.O. Box.

  2. 3D coordination framework [Ln(4)(mu(3)-OH)(2)Cu(6)I(5)(IN)(8)(OAc)(3)] (IN = isonicotinate): employing 2D layers of lanthanide wheel clusters and 1D chains of copper halide clusters.

    Science.gov (United States)

    Gu, Xiaojun; Xue, Dongfeng

    2007-06-25

    Two novel 3D heterometallic coordination polymers, Ln(4)(mu(3)-OH)(2)Cu(6)I(5)(IN)(8)(OAc)(3) (Ln = Nd (1), Pr (2); HIN = isonicotinic acid, HOAc = acetic acid), have been synthesized under hydrothermal conditions and characterized by elemental, infrared, and thermogravimetric analyses and single-crystal X-ray diffraction. Both compounds are isostructural and crystallize in the monoclinic system, space group P2(1)/c. Both polymers are constructed from 2D lanthanide-cluster polymers based on the {Ln(16)} wheel-cluster and 1D copper-cluster polymers based on the {Cu(6)I(5)} cluster, which represent the first examples of 3D coordination frameworks created by using a combination of two different types of metal-cluster polymer units, namely, a high-nuclearity lanthanide-cluster polymer and a transition-metal-cluster polymer.

  3. Efficient NiII2LnIII2Electrocyclization catalysts for the synthesis oftrans-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines

    OpenAIRE

    Griffiths, Kieran; Kumar, Prashant; Mattock, James D; Abdul-Sada, Alaa; Pitak, mateusz; Coles, Simon; Navarro, Oscar; Vargas, Alfredo; Kostakis, George E.

    2016-01-01

    A series of heterometallic coordination clusters (CCs) [NiII2LnIII2(L1)4Cl2(CH3CN)2] 2CH3CN [Ln = Y (1Y), Sm (1Sm), Eu (1Eu), Gd (1Gd), or Tb (1Tb)] were synthesized by the reaction of (E)-2-(2-hydroxy-3-methoxybenzylidene-amino)phenol) (H2L1) with NiCl2·6(H2O) and LnCl3·x(H2O) in the presence of Et3N at room temperature. These air-stable CCs can be obtained in very high yields from commercially available materials and are efficient catalysts for the room-temperature domino ring-opening elect...

  4. Systém virtuálního vzdělávání univerzity - analýza a návrh

    OpenAIRE

    Vožda, Petr

    2007-01-01

    Práce analyzuje a navrhuje systém virtuálního vzdělávání univerzity z konceptuálního hlediska. Tento systém je navržen jako portál virtuálního vzdělávání. Zvláštní pozornost je věnována procesům, objektům, uživatelskému rozhraní, komunikaci a také znalostem uvnitř navrhovaného systému. Jsou diskutována specifika různých typů vzdělávacích portálů. Důraz je kladen na flexibilitu a rozšiřitelnost systému.

  5. Eu(III) Complexes of Octadentate 1-Hydroxy-2-pyridinones: Stability and Improved Photophysical Performance

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Evan G.; D' Aleo, Anthony; Xu, Jide; Raymond, Kenneth N.

    2009-05-29

    The luminescence properties of lanthanoid ions can be dramatically enhanced by coupling them to antenna ligands that absorb light in the UV-visible and then efficiently transfer the energy to the lanthanoid centre. The synthesis and the complexation of Ln{sup III} cations (Ln = Eu, Gd) for a ligand based on four 1-hydroxy-2-pyridinone (1,2-HOPO) chelators appended to a ligand backbone derived by linking two L-lysine units (3LI-bis-LYS) is described. This octadentate Eu{sup III} complex ([Eu(3LI-bis-LYS-1,2-HOPO)]{sup -}) has been evaluated in terms of its thermodynamic stability, UV-visible absorption and luminescence properties. For this complex, the conditional stability constant (pM) is 19.9, which is an order of magnitude higher than diethylenetriaminepentacetic acid at pH = 7.4. This Eu{sup III} complex also shows an almost two-fold increase in its luminescence quantum yield in aqueous solution (pH = 7.4) when compared with other octadentate ligands. Hence, despite a slight decrease of the molar absorption coefficient, a much higher brightness is obtained for [Eu(3LI-bis-LYS-1,2-HOPO)]{sup -}. This overall improvement was achieved by saturating the coordination sphere of the Eu{sup III} cation, yielding an increased metal-centred efficiency by excluding solvent water molecules from the metal's inner sphere.

  6. Complex chemistry with complex compounds

    Directory of Open Access Journals (Sweden)

    Eichler Robert

    2016-01-01

    Full Text Available In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the investigation of fragile single molecular species by gas-phase chromatography. The latest success with the heaviest group 6 transactinide seaborgium is highlighted. The formation of a very volatile hexacarbonyl compound Sg(CO6 was observed similarly to its lighter homologues molybdenum and tungsten. The interactions of these gaseous carbonyl complex compounds with quartz surfaces were investigated by thermochromatography. Second-generation experiments are under way to investigate the intramolecular bond between the central metal atom of the complexes and the ligands addressing the influence of relativistic effects in the heaviest compounds. Our contribution comprises some aspects of the ongoing challenging experiments as well as an outlook towards other interesting compounds related to volatile complex compounds in the gas phase.

  7. Contributions on the investigation of inorganic nonstoichiometric compounds. XLV. New thermal decomposition products of Ln{sub 2}CeMO{sub 6}Cl{sub 3} - preparation of structure-related (La,Tb){sub 3.5}TaO{sub 6}Cl{sub 4-x}; Beitraege zur Untersuchung anorganischer nichtstoechiometrischer Verbindungen. XLV. Neue thermische Abbauprodukte von Ln{sub 2}CeMO{sub 6}Cl{sub 3} (M = Nb,Ta; Ln = La-Sm) - Darstellung von strukturverwandtem (La,Tb){sub 3,5}TaO{sub 6}Cl{sub 4-x}

    Energy Technology Data Exchange (ETDEWEB)

    Weitzel, H.; Behler, B.; Gruehn, R. [Giessen Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    1999-02-01

    The thermal decomposition (T {approx} 900-1050 C) of Ln{sub 2}CeMO{sub 6}Cl{sub 3} (M = Nb, Ta; Ln = La, Ce, Pr, Nd, Sm) leads to the formation of two mixed-valenced phases (Ln, Ce){sub 3.25}MO{sub 6}Cl{sub 3.5-x} (phase ``AB``) and (Ln, Ce){sub 3.5}MO{sub 6}Cl{sub 4-x} (phase ``BB``) and to the formation of chlorine according to redox-reactions between Ce{sup 4+} and Cl{sup -}. Single crystals of both phases (Ln, Ce){sub 3.25}MO{sub 6}Cl{sub 3.5-x} (``AB``) and (Ln, Ce){sub 3.5}MO{sub 6}Cl{sub 4-x} (``BB``) were obtained by chemical transport reactions using both powder of Ln{sub 2}CeMO{sub 6}Cl{sub 3} (phase ``A``) and powder of (Ln, Ce){sub 3.25}MO{sub 6}Cl{sub 3.5-x} (phase ``AB``) as starting materials and chlorine (p{l_brace}Cl{sub 2}; 298 K{r_brace} = 1 atm) or HCl (p{l_brace}HCl; 298 K{r_brace} = 1 atm) as transport agent. A crystal of (La, Ce){sub 3.25}NbO{sub 6}Cl{sub 3.5-x} (``AB``) (space group: C2/m, a = 35.288(1) A, b = 5.418(5) A, c = 9.522(1) A, {beta} = 98.95(7) , Z = 4) was investigated by X-ray diffraction methods, a crystal of (Pr, Ce){sub 3.5}NbO{sub 6}Cl{sub 4-x} (``BB``) was investigated by synchrotron radiation ({lambda} = 0.56 A) diffraction methods. The lattice constants are a = 18.863(6) A, b = 5.454(5) A, c = 9.527(6) A, {beta} = 102.44(3) and Z = 4. Structure determination in the space group C2/m (No. 12) let to R1 = 0.0313. Main building units are NbO{sub 6}-polyhedra with slightly distorted trigonally prismatic environment for Nb and chains of face-sharing Cl{sub 6}-octahedra along [010]. The rare earth ions are coordinated by chlorine and oxygen atoms. These main structure features confirmed the expected relation to the starting material Ln{sub 2}CeMO{sub 6}Cl{sub 3} (phase ``A``) and to (Ln, Ce){sub 3.25}MO{sub 6}Cl{sub 3.5-x} (phase ``AB``). (orig.)

  8. Managing Complexity

    Energy Technology Data Exchange (ETDEWEB)

    Chassin, David P.; Posse, Christian; Malard, Joel M.

    2004-08-01

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today’s most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically-based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This paper explores the state of the art in the use physical analogs for understanding the behavior of some econophysical systems and to deriving stable and robust control strategies for them. In particular we review and discussion applications of some analytic methods based on the thermodynamic metaphor according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood.

  9. Complex Questions Promote Complex Thinking

    Science.gov (United States)

    Degener, Sophie; Berne, Jennifer

    2017-01-01

    Intermediate-grade teachers often express concerns about meeting the Common Core State Standards for Reading, primarily because of the emphasis on deep understanding of complex texts. No matter how difficult the text, if teachers demand little of the reading, student meaning making is not challenged. This article offers a tool for teachers to…

  10. Covalent co-immobilization of heparin/laminin complex that with different concentration ratio on titanium surface for selectively direction of platelets and vascular cells behavior

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian; Chen, Yuan; Liu, Tao; Wang, Xue; Liu, Yang; Wang, Yuan; Chen, Junying, E-mail: chenjy@263.net; Huang, Nan

    2014-10-30

    Highlights: • Extracellular matrix inspired surface modification with fibronectin, heparin and VEGF to construct a favorable microenvironment for selectively anticoagulant and promote endothelialization. • Take the advantage of specific intermolecular interaction, the bioactivity of above biomolecules was more efficiently maintained in compared with the common used covalent immobilization method. • Poly-l-lysine was used as a novel interlayer for surface amination, and in comparison, PLL coating was more feasible and the degradation product had no harm to human body. - Abstract: Surface biofunctional modification of coronary artery stent to improve the hemocompatibility and selectively accelerate endothelium regeneration but prevent restenosis have been become a new hotspot. For this, a novel method was developed in this work by co-immobilization of Ln and heparin complex on poly-L-lysine modified Ti surface. Take the advantage of the specific interaction between Ln and heparin, Ln and heparin complexes with different concentration ratios were set up for creating different exposure density of these two types of biomolecules. According to biocompatibility evaluation results, the Hep/Ln complexes modified surface displayed less platelet adhesion and activation. Especially, on L(150)H and L(200)H surface, the AT III binding quantity, APTT value and anti-coagulation property of modified surface were significantly promoted. Furthermore, the adherent density and proliferation activity of ECs and EPCs were positively correlated with Ln concentration. Notably, the proliferation of both ECs and EPCs on L(100)H, L(150)H and L(200)H surface were greatly promoted. Another hand, the proliferation activity of SMCs was significantly inhibited on Hep/Ln modified surfaces, which was considered mainly due to the inhibitory effect of heparin to SMCs. According to the existing results, this study demonstrated that in a certain range of heparin and laminin concentration ratio

  11. Complex variables

    CERN Document Server

    Flanigan, Francis J

    2010-01-01

    A caution to mathematics professors: Complex Variables does not follow conventional outlines of course material. One reviewer noting its originality wrote: ""A standard text is often preferred [to a superior text like this] because the professor knows the order of topics and the problems, and doesn't really have to pay attention to the text. He can go to class without preparation."" Not so here-Dr. Flanigan treats this most important field of contemporary mathematics in a most unusual way. While all the material for an advanced undergraduate or first-year graduate course is covered, discussion

  12. Complex variables

    CERN Document Server

    Taylor, Joseph L

    2011-01-01

    The text covers a broad spectrum between basic and advanced complex variables on the one hand and between theoretical and applied or computational material on the other hand. With careful selection of the emphasis put on the various sections, examples, and exercises, the book can be used in a one- or two-semester course for undergraduate mathematics majors, a one-semester course for engineering or physics majors, or a one-semester course for first-year mathematics graduate students. It has been tested in all three settings at the University of Utah. The exposition is clear, concise, and lively

  13. Syntheses, crystal structures, visible and near-IR luminescent properties of ternary lanthanide (Dy{sup 3+}, Tm{sup 3+}) complexes containing 4,4,4-trifluoro-1-phenyl-1,3-butanedione and 1,10-phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jing [State Key Laboratory of Rare Earth Resource Utilizations, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 renmin street, Changchun 130022 (China); Graduate School of the Chinese Academy of Sciences, Beijing (China); Zhang Hongjie [State Key Laboratory of Rare Earth Resource Utilizations, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 renmin street, Changchun 130022 (China)], E-mail: hongjie@ciac.jl.cn; Song Shuyan; Li Zhefeng; Sun Lining [State Key Laboratory of Rare Earth Resource Utilizations, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 renmin street, Changchun 130022 (China); Graduate School of the Chinese Academy of Sciences, Beijing (China); Xing Yan [State Key Laboratory of Rare Earth Resource Utilizations, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 renmin street, Changchun 130022 (China); Guo Xianmin [State Key Laboratory of Rare Earth Resource Utilizations, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 renmin street, Changchun 130022 (China); Graduate School of the Chinese Academy of Sciences, Beijing (China)

    2008-12-15

    The ligands 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbfa) and 1,10-phenanthroline (phen) were used to prepare ternary lanthanide (Ln) complexes [Dy(bfa){sub 3}phen and Tm(bfa){sub 3}phen]. Crystal data: Dy(bfa){sub 3}phen C{sub 42}H{sub 26}F{sub 9}N{sub 2}O{sub 6}Dy, triclinic, P1-bar , a=9.9450(6) A, b=14.0944(9) A, c=14.6043(9) A, {alpha}=82.104(1){sup o}, {beta}=87.006(1){sup o}, {gamma}=76.490(1){sup o}, V=1971.1(2) A{sup 3}, Z=2; Tm(bfa){sub 3}phen C{sub 42}H{sub 26}F{sub 9}N{sub 2}O{sub 6}Tm, triclinic, P1-bar , a=9.898(5) A, b=13.918(5) A, c=14.753(5) A, {alpha}=83.517(5){sup o}, {beta}=86.899(5){sup o}, {gamma}=76.818(5){sup o}, V=1965.3(14) A{sup 3}, Z=2. The coordination number of the central Ln{sup 3+} (Ln=Dy, Tm) ion is eight, with six oxygen atoms from three Hbfa ligands and two nitrogen atoms from the phen ligand. The photophysical properties of the two complexes were studied by absorption spectra, diffuse reflectance spectra, and emission spectra. They show the characteristic luminescence of the corresponding Ln{sup 3+} ion in both visible and near-IR (NIR) region. Additionally, the energy transfer mechanisms between the ligands and central Ln{sup 3+} ions were discuss0008.

  14. Solution synthesis, structure, and CO{sub 2} reduction reactivity of a Scandium(II) complex, {Sc[N(SiMe_3)_2]_3}{sup -}

    Energy Technology Data Exchange (ETDEWEB)

    Woen, David H.; Chen, Guo P.; Ziller, Joseph W.; Furche, Filipp; Evans, William J. [Department of Chemistry, University of California, Irvine, CA (United States); Boyle, Timothy J. [Sandia National Laboratories, Advanced Materials Laboratory, Albuquerque, NM (United States)

    2017-02-13

    The first crystallographically characterizable complex of Sc{sup 2+}, [Sc(NR{sub 2}){sub 3}]{sup -} (R=SiMe{sub 3}), has been obtained by LnA{sub 3}/M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR{sub 2}){sub 3} with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)]{sup +}, [K(18-c-6)]{sup +}, and [Cs(crypt)]{sup +} salts of the [Sc(NR{sub 2}){sub 3}]{sup -} anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 {sup 45}Sc nucleus. The Sc(NR{sub 2}){sub 3} reduction differs from Ln(NR{sub 2}){sub 3} reactions (Ln=Y and lanthanides) in that it occurs under N{sub 2} without formation of isolable reduced dinitrogen species. [K(18-c-6)][Sc(NR{sub 2}){sub 3}] reacts with CO{sub 2} to produce an oxalate complex, {K_2(18-c-6)_3}{[(R_2N)_3Sc]_2(μ-C_2O_4-κ"1O:κ"1O'')}, and a CO{sub 2}{sup -} radical anion complex, [(R{sub 2}N){sub 3}Sc(μ-OCO-κ{sup 1}O:κ{sup 1}O')K(18-c-6)]{sub n}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Complex dynamics

    CERN Document Server

    Carleson, Lennart

    1993-01-01

    Complex dynamics is today very much a focus of interest. Though several fine expository articles were available, by P. Blanchard and by M. Yu. Lyubich in particular, until recently there was no single source where students could find the material with proofs. For anyone in our position, gathering and organizing the material required a great deal of work going through preprints and papers and in some cases even finding a proof. We hope that the results of our efforts will be of help to others who plan to learn about complex dynamics and perhaps even lecture. Meanwhile books in the field a. re beginning to appear. The Stony Brook course notes of J. Milnor were particularly welcome and useful. Still we hope that our special emphasis on the analytic side will satisfy a need. This book is a revised and expanded version of notes based on lectures of the first author at UCLA over several \\Vinter Quarters, particularly 1986 and 1990. We owe Chris Bishop a great deal of gratitude for supervising the production of cour...

  16. and complex

    Directory of Open Access Journals (Sweden)

    Kamrin Ken

    2017-01-01

    Full Text Available Granular materials have a strange propensity to behave as either a complex media or a simple media depending on the precise question being asked. This review paper offers a summary of granular flow rheologies for well-developed or steady-state motion, and seeks to explain this dichotomy through the vast range of complexity intrinsic to these models. A key observation is that to achieve accuracy in predicting flow fields in general geometries, one requires a model that accounts for a number of subtleties, most notably a nonlocal effect to account for cooperativity in the flow as induced by the finite size of grains. On the other hand, forces and tractions that develop on macro-scale, submerged boundaries appear to be minimally affected by grain size and, barring very rapid motions, are well represented by simple rate-independent frictional plasticity models. A major simplification observed in experiments of granular intrusion, which we refer to as the ‘resistive force hypothesis’ of granular Resistive Force Theory, can be shown to arise directly from rate-independent plasticity. Because such plasticity models have so few parameters, and the major rheological parameter is a dimensionless internal friction coefficient, some of these simplifications can be seen as consequences of scaling.

  17. Structural and catalytic properties of some azo-rhodanine Ruthenium(III) complexes

    Science.gov (United States)

    Shoair, A. F.; El-Bindary, A. A.; Abd El-Kader, M. K.

    2017-09-01

    Novel azo-rhodanine ruthenium(III) complexes of the type trans-[Ru(Ln)2(AsPh3)2]Cl (Ln = monobasic bidentate anions of 5-(4‧-methoxyphenylazo)-3-phenylamino-2-thioxothiazolidin-4-one (HL1), 5-(phenylazo)-3-phenylamino-2-thioxothiazolidin-4-one (HL2) and 5-(4‧-chlorophenylazo)-3-phenylamino-2-thioxothiazolidin-4-one (HL3); AsPh3 = triphenylarsine) have been synthesized and characterized by elemental analysis, spectroscopic (IR, 1H NMR and UV-VIS), magnetic, X-ray diffraction, mass spectra and thermal analysis techniques. These techniques confirm the formation of octahedral ruthenium(III) complexes. The Ru(III) complexes were tested as a catalysts for the oxidation of benzyl alcohol to benzaldehyde with N-methylmorpholine-N-oxide as a co-oxidant. The effect of time, temperature, and solvent were also studied and the mechanism of this catalytic oxidation reaction is suggested. Molecular docking was used to predict the binding between azo rhodanine derivatives (HLn) with the receptor of 3qum- immune system receptor of human prostate specific antigen (PSA) in a Fab sandwich with a high affinity and a PCa selective antibody.

  18. Synthesis, structural characterization and Mössbauer study of LnV{sub 0.5}Fe{sub 0.5}O{sub 3} perovskites (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Ivashita, Flávio F.; Biondo, Valdecir; Bellini, Jusmar V.; Paesano, Andrea [Departamento de Física, Universidade Estadual de Maringá, Av. Colombo 5790, 87.020-900 Maringá, PR (Brazil); Blanco, M. Cecilia; Fuertes, Valeria C.; Pannunzio-Miner, Elisa V. [INFIQC-CONICET, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba (Argentina); Carbonio, Raúl E., E-mail: carbonio@fcq.unc.edu.ar [INFIQC-CONICET, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba (Argentina)

    2012-09-15

    Graphical abstract: Mössbauer spectra taken at 200 K for the Y(V{sub 0.5}Fe{sub 0.5})O{sub 3} orthoferrivanadate synthesized by arc-melting. Highlights: ► LnFe{sub 0.5}V{sub 0.5}O{sub 3} were synthesized by the first time for most of the rare-earth elements. ► These orthoferrivanadates crystallize metastably with the perovskite structure. ► Iron and vanadium are trivalent stabilized in these solid solutions. ► The Mössbauer quadrupolar splitting is correlated with the tolerance factor. ► Below 100 K, these perovskites undergo a crystallographic phase transformation. -- Abstract: Perovskites LnV{sub 0.5}Fe{sub 0.5}O{sub 3} (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er) were synthesized by rapid solidification from arc-melted samples and characterized by the study of their crystal structure and hyperfine properties. These metastable solid solutions crystallized in the Pbnm symmetry, with the iron and vanadium cations randomly distributed in the transition metal octahedral sites. Depending on the lanthanide present at the A site of the perovskite, iron is present with two valences (i.e., Fe{sup 3+} and Fe{sup 2+}). The volume of the unit cell for these perovskites increases linearly with the lanthanide ionic radius, as the perovskite approaches its ideal structure. At room temperature, the quadrupolar splitting of the trivalent paramagnetic Mössbauer component works as an indirect measurement for the Goldshmidt tolerance factor. Close to or below 100 K, these perovskites undergo a crystallographic phase transformation, probably due to orbital ordering of the V{sup 3+} cations, originating two different magnetic iron sites.

  19. Dynamic Mechanical Properties and Fracture Surface Morphologies of Core-Shell Rubber (CSR) Toughened Epoxy at Liquid Nitrogen (Ln2) Temperatures

    Science.gov (United States)

    Wang, J.; Magee, D.; Schneider, J. A.

    2009-01-01

    The dynamic mechanical properties and fracture surface morphologies were evaluated for a commercial epoxy resin toughened with two types of core-shell rubber (CSR) toughening agents (Kane Ace(Registered TradeMark) MX130 and MX960). The impact resistance (R) was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The resulting fracture surface morphologies were examined using Scanning Electron Microscopy (SEM). Fractographic observations of the CSR toughened epoxy tested at ambient temperature, showed a fracture as characterized by slender dendrite textures with large voids. The increasing number of dendrites and decreasing size of scale-like texture with more CSR particles corresponded with increased R. As the temperature decreased to Liquid Nitrogen (LN 2), the fracture surfaces showed a fracture characterized by a rough, torn texture containing many river markings and deep furrows.

  20. Cosmic Complexity

    Science.gov (United States)

    Mather, John C.

    2012-01-01

    What explains the extraordinary complexity of the observed universe, on all scales from quarks to the accelerating universe? My favorite explanation (which I certainty did not invent) ls that the fundamental laws of physics produce natural instability, energy flows, and chaos. Some call the result the Life Force, some note that the Earth is a living system itself (Gaia, a "tough bitch" according to Margulis), and some conclude that the observed complexity requires a supernatural explanation (of which we have many). But my dad was a statistician (of dairy cows) and he told me about cells and genes and evolution and chance when I was very small. So a scientist must look for me explanation of how nature's laws and statistics brought us into conscious existence. And how is that seemll"!gly Improbable events are actually happening a!1 the time? Well, the physicists have countless examples of natural instability, in which energy is released to power change from simplicity to complexity. One of the most common to see is that cooling water vapor below the freezing point produces snowflakes, no two alike, and all complex and beautiful. We see it often so we are not amazed. But physlc!sts have observed so many kinds of these changes from one structure to another (we call them phase transitions) that the Nobel Prize in 1992 could be awarded for understanding the mathematics of their common features. Now for a few examples of how the laws of nature produce the instabilities that lead to our own existence. First, the Big Bang (what an insufficient name!) apparently came from an instability, in which the "false vacuum" eventually decayed into the ordinary vacuum we have today, plus the most fundamental particles we know, the quarks and leptons. So the universe as a whole started with an instability. Then, a great expansion and cooling happened, and the loose quarks, finding themselves unstable too, bound themselves together into today's less elementary particles like protons and

  1. Enantioselective resolutions and circular dichroism studies of lanthanide-containing Keggin-type [Ln(PW11O39)2](11-) polyoxometalates.

    Science.gov (United States)

    Naruke, Haruo; Iijima, Jun; Sanji, Takanobu

    2011-08-15

    Enantiopure crystals of K(1.3)Na(3.2)H(6.5)[l-Pr(PW(11)O(39))(2)]·8.3l-proline·21.5H(2)O (1), K(1.3)Na(3.2)H(6.5)[d-Pr(PW(11)O(39))(2)]·8.3d-proline·17H(2)O (2), and K(1.3)Na(3.2)H(6.5)[l-Er(PW(11)O(39))(2)]·8.3l-proline·22.5H(2)O (3) were successfully obtained by using l- and d-proline (pro) as chiral auxiliary agents. In these crystals, l- and d-[Ln(PW(11)O(39))(2)](11-) anions are attached by two l- and d-pro molecules, respectively, through a O···N hydrogen-bonding interaction between the square-antiprismatic LnO(8) center and amino-N atoms. The l- and d-[Pr(PW(11)O(39))(2)](11-) anions in aqueous solutions exhibited a couple of mirror-imaged CD spectra due to (3)H(4/2)→(3)P(0,1,2) and (1)D(2) transitions in the stereogenic Pr(3+) center. Chirality inductions by l- and d-pro from a racemic solution of [Er(PW(11)O(39))(2)](11-) was demonstrated by means of CD spectroscopy. © 2011 American Chemical Society

  2. Photoluminescence and electron-vibrational interaction in 4f{sup n-1}5d states of Ce{sup 3+} or Pr{sup 3+} ions doped LnBO{sub 3} (Ln=Lu, Y, La) orthoborates materials

    Energy Technology Data Exchange (ETDEWEB)

    Guerbous, L., E-mail: guerbous@yahoo.fr [Laser Department, Nuclear Techniques Division, Algiers Nuclear Research Center, 02, bd Frantz Fanon, BP 399, Algiers 16000 (Algeria); Seraiche, M. [Laser Department, Nuclear Techniques Division, Algiers Nuclear Research Center, 02, bd Frantz Fanon, BP 399, Algiers 16000 (Algeria); Department of Materials and Components, Faculty of Physics, USTHB (Algeria); Krachni, O. [Departement de Physique, Faculte des Sciences, Universite Ferhat Abbas Setif 19000 (Algeria)

    2013-02-15

    Calcite, vaterite and aragonite type rare earth LnBO{sub 3} (Ln=Lu, Y, La) orthoborate powders, doped with 1% cerium or praseodymium, were prepared by the classical solid state reaction method. The structure and the morphology of these powder materials were checked by X-ray Diffraction, Fourier Transform Infra Red Spectroscopy (FTIR) and Scanning Electron Microscopy. Room temperature excitation and emission spectra of four compounds: LuBO{sub 3} with calcite and vaterite structure, YBO{sub 3} (vaterite type structure) and LaBO{sub 3} with aragonite, doped with 1% cerium or praseodymium ions, have been measured and investigated. The effect of Ce{sup 3+} and Pr{sup 3+} crystalline environment in these compounds on the position of their 5d (4f5d) levels has been discussed. This work is also devoted to the problem of the electron-vibrational interaction (EVI) in 4f-5d optical transitions in orthoborate materials. The emission and excitation 4f-5d transitions resulted in broad vibronic bands whose shape functions were described and found. The main EVI parameters, such as the Huang-Rhys factor, effective phonon energy, and zero-phonon line position, were estimated. These values are checked by modeling the Ce{sup 3+} 5d-4f and Pr{sup 3+} 4f5d-4f{sup 2} emission lines shapes, in which good agreement with experimental spectra confirms validity of the performed analysis. - Highlights: Black-Right-Pointing-Pointer Ce{sup 3+} and Pr{sup 3+}-doped calcite, vaterite and aragonite LnBO{sub 3} (Ln=Lu, Y, La) orthoborates were successfully prepared by the solid state reaction method. Black-Right-Pointing-Pointer The effect of Ce{sup 3+} and Pr{sup 3+} crystalline environment in orthoborates on the position of their 5d levels has been discussed. Black-Right-Pointing-Pointer The main electron-vibrational interaction parameters (EVI), such as the Huang-Rhys factor, effective phonon energy, and zero-phonon line position, were estimated and discussed.

  3. Effect of A-site cation size on magnetic and charge-ordering properties of Ln{sub 0.5}Sr{sub 0.5}Mn{sub 0.9}Cu{sub 0.1}O{sub 3} (Ln = La, Pr, Nd, or Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Kamlesh [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India); Singh, M.P.; Razavi, F.S. [Department of Physics, Brock University, 500 Glenridge Ave, St Catharines L2S 3A1 (Canada); Varma, G.D., E-mail: gdvarfph@iitr.ernet.in [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India)

    2012-08-20

    Highlights: Black-Right-Pointing-Pointer The structural, magnetic, and electrical properties of Ln{sub 0.5}Sr{sub 0.5}Mn{sub 0.9}Cu{sub 0.1}O{sub 3} (Ln = La, Pr, Nd, or Ho) have been studied. Black-Right-Pointing-Pointer The influence of A-site cation radius ( Left-Pointing-Angle-Bracket r{sub A} Right-Pointing-Angle-Bracket ) and the A-site cation size-disorder ({sigma}{sup 2}) on magnetic properties are studied. Black-Right-Pointing-Pointer The various interdependent phenomena such as ferromagnetism, phase separation, and charge ordering are investigated. - Abstract: The structural, magnetic, and electrical properties of Ln{sub 0.5}Sr{sub 0.5}Mn{sub 0.9}Cu{sub 0.1}O{sub 3} (Ln = La, Pr, Nd, or Ho) perovskite manganites have been investigated to explore the influence of A-site cation radius ( Left-Pointing-Angle-Bracket r{sub A} Right-Pointing-Angle-Bracket ) and the A-site cation size-disorder ({sigma}{sup 2}) on the various interdependent phenomena such as ferromagnetism (FM), phase separation (PS), and charge ordering (CO). The temperature dependence magnetization (M-T) curve of La-based sample shows four distinct points at {approx}269 K, 255 K, 200 K, and 148 K corresponding to strong FM, cluster glass (CG), weak FM, and charged ordered antiferromagnetic (COAFM) transitions, respectively. Our investigation shows that Neel temperatures (T{sub N}) increases, whereas Curie (T{sub C}) and irreversibility temperatures (T{sub irr}) decrease with decreasing Left-Pointing-Angle-Bracket r{sub A} Right-Pointing-Angle-Bracket , i.e., with increasing {sigma}{sup 2}. Furthermore, the value of the magnetization decreases and resistivity increases with decreasing Left-Pointing-Angle-Bracket r{sub A} Right-Pointing-Angle-Bracket . All samples exhibit insulating behavior in the temperature range 77-300 K and above 110 K the electronic conduction mechanism has been described within the framework of the variable range hopping (VRH) model.

  4. Zákaz diskriminace na základě pohlaví a sexuální obtěžování v pracovních vztazích

    OpenAIRE

    Kimlová, Jana

    2009-01-01

    Stav právní úpravy sexuálního obtěžování v ČR není zdaleka ideální. Úprava v zákoníku práce je z pohledu diskriminace nedostatečná, protože předpokládala speciální úprava zakotvenou v antidiskriminačním zákoně. Zákoník práce tak obsahuje pouze obecné zakotvení zásady rovného zacházení a v otázkách ochrany odkazuje na dosud neschválený právní předpis. Možnost efektivně se bránit sexuálnímu obtěžování před soudem je za současné situace tudíž značně zkomplikována. Necháme-li stranou případy sexu...

  5. In vitro and in vivo anti-inflammatory active copper(II)-lawsone complexes.

    Science.gov (United States)

    Vančo, Ján; Trávníček, Zdeněk; Hošek, Jan; Suchý, Pavel

    2017-01-01

    We report in vitro and in vivo anti-inflammatory activities of a series of copper(II)-lawsone complexes of the general composition [Cu(Law)2(LN)x(H2O)(2-x)]·yH2O; where HLaw = 2-hydroxy-1,4-naphthoquinone, x = 1 when LN = pyridine (1) and 2-aminopyridine (3) and x = 2 when LN = imidazole (2), 3-aminopyridine (4), 4-aminopyridine (5), 3-hydroxypyridine (6), and 3,5-dimethylpyrazole (7). The compounds were thoroughly characterized by physical techniques, including single crystal X-ray analysis of complex 2. Some of the complexes showed the ability to suppress significantly the activation of nuclear factor κB (NF-κB) both by lipopolysaccharide (LPS) and TNF-alpha (complexes 3-7 at 100 nM level) in the similar manner as the reference drug prednisone (at 1 μM level). On the other hand, all the complexes 1-7 decreased significantly the levels of the secreted TNF-alpha after the LPS activation of THP-1 cells, thus showing the anti-inflammatory potential via both NF-κB moderation and by other mechanisms, such as influence on TNF-alpha transcription and/or translation and/or secretion. In addition, a strong intracellular pro-oxidative effect of all the complexes has been found at 100 nM dose in vitro. The ability to suppress the inflammatory response, caused by the subcutaneous application of λ-carrageenan, has been determined by in vivo testing in hind-paw edema model on rats. The most active complexes 1-3 (applied in a dose corresponding to 40 μmol Cu/kg), diminished the formation of edema simalarly as the reference drug indomethacine (applied in 10 mg/kg dose). The overall effect of the complexes, dominantly 1-3, shows similarity to anti-inflammatory drug benoxaprofen, known to induce intracellular pro-oxidative effects.

  6. Identita, komunita a teorie symbolické interakce v digitálním věku

    OpenAIRE

    Bartoň, Petr

    2008-01-01

    The thesis presents a compilation about social relations and identity formation via digital technology and new media, internet in the first place. The author, with the regard to contemporary processes as globalization and rapid digital technology development, mainly relates to two topics, following the view of complexity, mutual implications, cohesion and conditionality of individual identity, interpersonal relationships and social relations, from the perspective of symbolic interaction theor...

  7. Sociálně-ekonomické postavení českého učitele

    OpenAIRE

    Melicharová, Tereza

    2016-01-01

    Theoretical part of dissertation was focused to defined concept teacher and his social and economic position. These concepts were focused from professional literature and law of Czech Republic. Practical part then is turn on in first line on the research of teacher's job. Some of them refer to prestige of teacher, another generally teachers position, his intensity and complexity, another was devoted education system universally. The second part explores from qualitative research of some respo...

  8. Copper(II) complexes derived from di-2-pyridyl ketone- N4-phenyl-3-semicarbazone: Synthesis and spectral studies

    Science.gov (United States)

    Reena, T. A.; Kurup, M. R. Prathapachandra

    2010-08-01

    Five copper(II) complexes [CuLCl] 2·CuCl 2·4H 2O ( 1), [CuLOAc] ( 2), [CuLNO 3] 2 ( 3), [CuLN 3] ( 4) and [CuLNCS]·3/2H 2O ( 5) of di-2-pyridyl ketone- N4-phenyl-3-semicarbazone (HL) were synthesized and characterized by elemental analyses and electronic, infrared and EPR spectral techniques. In all these complexes the semicarbazone undergoes deprotonation and coordinates through enolate oxygen, azomethine and pyridyl nitrogen atoms. All the complexes are EPR active due to the presence of an unpaired electron. EPR spectra of all the complexes in DMF at 77 K suggest axial symmetry and the presence of half field signals for the complexes 1 and 3 indicates dimeric structures.

  9. Facile synthesis, structural and spectroscopic properties of GdF{sub 3}:Ce{sup 3+}, Ln{sup 3+} (Ln{sup 3+}=Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanocrystals with bright multicolor luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz; Runowski, Marcin; Lis, Stefan, E-mail: blis@amu.edu.pl

    2014-10-15

    Hexagonal gadolinium fluorides doped with Ce{sup 3+} ions and co-doped with Sm{sup 3+}, Eu{sup 3+}, Tb{sup 3+} or Dy{sup 3+} were successfully synthesized via a simple co-precipitation approach, in the presence of glycerin as a capping agent. These fluorides, as solids or in aqueous solutions, showed intense, multicolored luminescence depending on the lanthanide ions used. The structures of the products were confirmed by powder X-ray diffraction (XRD). The morphologies of the synthesized nanophosphors were examined using transmission electron microscopy (TEM). The TEM results showed that the crystallites had shapes that varied with the dopant ion used. The spectroscopic properties: excitation spectra, emission spectra and luminescence decays were recorded and studied in detail. Bright luminescences from all of the products were triggered by effective energy transfer between the ions embedded in their structures. The mechanism for this phenomenon was also proposed. All of the synthesized products formed stable aqueous colloids, exhibiting brightly multicolored luminescence under UV light irradiation. - Highlights: • Hexagonal GdF{sub 3}:Ce{sup 3+}, Ln{sup 3+} nanocrystals were synthesized by a co-precipitation method. • Nanocrystals formed stable water colloids. • Multicolor luminescence under UV light was observed. • Energy transfer mechanism between Gd{sup 3+}, Ce{sup 3+} and Ln{sup 3+} ions was proposed.

  10. Combinatorial screening of luminescent and structural properties in a Ce(3+)-doped Ln-Al-Si-O-N (Ln = Y, La, Gd, Lu) system: the discovery of a novel Gd3Al(3+x)Si(3-x)O(12+x)N(2-x):Ce(3+) phosphor.

    Science.gov (United States)

    Park, Woon Bae; Singh, Satendra Pal; Kim, Minseuk; Sohn, Kee-Sun

    2015-02-16

    The discovery of novel phosphors for use in light emitting diodes (LED) has gained in significance because LED-based solid-state lighting applications now attract a great deal of attention for energy savings and environmental concerns. Recent research trends have centered on the discovery of novel phosphors, not on slight variations of well-known phosphors. In a real sense, novelty goes beyond simple variations or improvements in existing phosphors. A brilliant strategy for the discovery of novel phosphors is to introduce an appropriate activator to existing inorganic compounds. These compounds have structures that are well-defined in crystallographic structure databases, but they have never been considered as a phosphor host. Another strategy is to discover new host compounds with structures that cannot be found in existing databases. We have simultaneously pursued both strategies by employing metaheuristics-assisted combinatorial material search techniques. In the present investigation, we screened a search space consisting of Ln-Al-Si-O-N (Ln = Y, La, Gd, Lu), and thereby we discovered a blue-light-emitting novel phosphor, Gd3Al(3+x)Si(3-x)O(12+x)N(2-x):Ce(3+), with a monoclinic system in the C2 space group--a potential candidate for UV-LED applications.

  11. Effect of lanthanide on the microstructure and structure of LnMn{sub 0.5}Fe{sub 0.5}O{sub 3} nanoparticles with Ln=La, Pr, Nd, Sm and Gd prepared by the polymer precursor method

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Mariano [Centro NanoMat/Cryssmat Lab/Cátedra de Física—DETEMA, Facultad de Química—UdelaR, Montevideo (Uruguay); Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales—UdelaR, Montevideo (Uruguay); Faccio, Ricardo, E-mail: rfaccio@fq.edu.uy [Centro NanoMat/Cryssmat Lab/Cátedra de Física—DETEMA, Facultad de Química—UdelaR, Montevideo (Uruguay); Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales—UdelaR, Montevideo (Uruguay); Martínez, Javier [Departamento de Física de La Plata, Universidad Nacional de La Plata, La Plata (Argentina); Instituto de Física de La Plata, CCT-La Plata—CONICET, La Plata (Argentina); Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Corrientes (Argentina); Pardo, Helena; Montenegro, Benjamín [Centro NanoMat/Cryssmat Lab/Cátedra de Física—DETEMA, Facultad de Química—UdelaR, Montevideo (Uruguay); Centro Interdisciplinario de Nanotecnología, Química y Física de Materiales—UdelaR, Montevideo (Uruguay); Plá Cid, Cristiani Campos; Pasa, André A. [Laboratorio Central de microscopía electrónica, Universidad Federal de Santa Catarina, Florianópolis (Brazil); and others

    2015-01-15

    The synthesis of LnMn{sub 0.5}Fe{sub 0.5}O{sub 3} perovskite nanoparticles by the polymer precursor method showed a strong intrinsic dependence with different lanthanides (Ln=La, Pr, Nd, Sm and Gd). The polymerization level reached in the polymer precursor was proportional to the atomic number of lanthanide with exception of samarium, which showed the formation of a different precursor based in a citrate chelate with ethyleneglycol bonded as adduct. The increasing level of polymerization of the polymer precursors showed the formation of large-size perovskite nanoparticles after its calcination. SAXS and TEM analyses suggested that nanoparticles obtained, using this method, have a squared-like microstructure in connection with the polymer precursor microstructure. Structural analysis showed an orthorhombic structure with a slight decline in the Jahn–Teller distortion when the atomic number of lanthanide increases. Mössbauer spectroscopy showed the presence of a majority site in agreement with the Pbnm orthorhombic structure best fitted with Rietveld refinements and in some cases, a more distorted site attributed to local inhomogeneities and oxygen vacancies. - Highlights: • Precursor polymerization level is lower in the presence of lighter lanthanides. • Lighter lanthanide perovskite nanoparticles after calcination are lower-sized. • Nanoparticles obtained by this method have lamellae microstructure. • Jahn–Teller distortion declines for heavier lanthanide perovskites. • Oxygen vacancy phase was observed in lighter lanthanide perovskites.

  12. Assessment of postural stability in patients with a transtibial amputation with various times of prosthesis use [Hodnocení posturální stability pacientů s transtibiální amputací s různou dobou používání protézy

    Directory of Open Access Journals (Sweden)

    Dagmar Kozáková

    2009-09-01

    for COP sways in a mediolateral direction and for COP movement velocity in both anteroposterior and mediolateral directions (p < 0.01, p < 0.05. We did not find differences between all the tested standing modifications (except for the natural bipedal standing position in sways and COP velocity movements. With a prolonged period of waiting for a prosthesis fitting we can observe an enlarged asymmetry of body weight distribution between the legs and also a higher range of COP sway and velocity. CONCLUSIONS: In all measurements in patients with a transtibial amputation, our results show a greater loading on the sound limb compared to the prosthetic one. Faster prosthesis fitting decreases asymmetry from body weight distribution between both of the legs. The basic goal of achieving full value life in patients after lower limb amputation is a tendency towards early prosthesis fitting. [VÝCHODISKA: Ztráta somatosenzorické informace z dolní končetiny způsobená amputací se podílí na vzniku potíží při udržení posturální stability, které zvyšují riziko pádu. Snaha o včasné vybavení protézou, při zohlednění všech působících vlivů (typ amputace, zdravotní stav pacienta, finanční náročnost apod., je nezbytným předpokladem pro návrat osob s amputací do běžného života. CÍLE: Cílem studie bylo zhodnocení vybraných biomechanických parametrů stability stoje u osob s transtibiální amputací s různou dobou používání protézy. Dále posouzení vlivu doby čekání na vybavení protetickou pomůckou na stabilitu stoje v různých situacích. METODIKA: Sledovaný soubor tvořilo 21 pacientů (průměrný věk 64,4 ± 9,18 let s jednostrannou transtibiální amputací. Příčinou amputace bylo u 12 testovaných osob cévní onemocnění, u 8 testovaných osob trauma a u 1 tumor. Průměrná délka používání protézy byla 156,4 ± 359,6 dnů. Pravostrannou transtibiální amputaci mělo 10 pacientů, 11 amputaci levostrannou. K

  13. Hemoglobina Köln diagnosticada em programa de triagem neonatal em São José do Rio Preto, SP Köln Hemoglobin found in Neonatal Screening Program in São José do Rio Preto, São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Emanuele C. Schiaveto

    2002-03-01

    Full Text Available Alterações genéticas em que a mutação de aminoácidos nas globinas afeta a estrutura da molécula tornando-a instável são classificadas como hemoglobinas instáveis. Devido à grande diversidade dos pontos de mutações por substituições e deleções de aminoácidos, as formas de instabilização se apresentam muito variadas. A hemoglobina Köln é a variante instável descrita com maior freqüência na literatura e a terceira descoberta no Brasil, as outras são Hb Niterói e Hb Hasharon. Anemia moderada, icterícia e presença de urina escura caracterizam as manifestações clínicas da Hb Köln. Em programa de triagem neonatal identificamos uma criança com suspeita de heterozigose para hemoglobina Köln, confirmada por procedimentos eletroforéticos e HPLC. Avaliações por diferentes metodologias laboratoriais e estudo familiar auxiliam no diagnóstico precoce, possibilitando minimizar os sintomas decorrentes da hemoglobina anormal e a realização do aconselhamento genético e educacional destas alterações hereditárias.Hemoglobinopathies are a diverse group of inherited recessive disorders that include thalassemias and sickle cell disease. They were the first genetic diseases to be characterized at the molecular level and consequently have been used repeatedly as a prototype for the development of new techniques of mutation detection. A major group of the structural hemoglobins exhibit the property of instability in solution, resulting from their altered molecular structures. Mutation of amino acids in the globin affects the structure of the molecule turning it unstable and they are classified as unstable hemoglobins. Due to the great diversity of the mutation points, substitutions and deletions of amino acids, the unstable forms are very varied. Hemoglobin Köln is the unstable variant most described in literature and the third discovered in Brazil, the others are Hb Niterói and Hb Hasharon. Moderate anemia, jaundice and the

  14. Dramatická výchova a osobnostní a sociální rozvoj

    OpenAIRE

    Pauzová, Veronika

    2010-01-01

    Synopsis This dissertation work deals with the possibilities of personal and social development of pupils through Drama in Education. The practical part creates a complex of ten eighty-minute lessons that have been realized in the ten weeks in the fourth class of primary school operating on the principles of Montessori. It describes the work of the teacher the beginner beginning with a class, which until then had no experience of Drama in Education. It tries to capture how successful it is to...

  15. Visible-near-infrared luminescent lanthanide ternary complexes based on beta-diketonate using visible-light excitation.

    Science.gov (United States)

    Sun, Lining; Qiu, Yannan; Liu, Tao; Feng, Jing; Deng, Wei; Shi, Liyi

    2015-11-01

    We used the synthesized dinaphthylmethane (Hdnm) ligand whose absorption extends to the visible-light wavelength, to prepare a family of ternary lanthanide complexes, named as [Ln(dnm)3 phen] (Ln = Sm, Nd, Yb, Er, Tm, Pr). The properties of these complexes were investigated by Fourier transform infrared (FT-IR) spectroscopy, diffuse reflectance (DR) spectroscopy, thermogravimetric analyses, and excitation and emission spectroscopy. Generally, excitation with visible light is much more advantageous than UV excitation. Importantly, upon excitation with visible light (401-460 nm), the complexes show characteristic visible (Sm(3+)) as well as near-infrared (Sm(3+), Nd(3+), Yb(3+), Er(3+), Tm(3+), Pr(3+)) luminescence of the corresponding lanthanide ions, attributed to the energy transfer from the ligands to the lanthanide ions, an antenna effect. Now, using these near-infrared luminescent lanthanide complexes, the luminescent spectral region from 800 to 1650 nm, can be covered completely, which is of particular interest for biomedical imaging applications, laser systems, and optical amplification applications. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Single-molecule magnet behavior in 2,2’-bipyrimidine-bridged dilanthanide complexes

    Directory of Open Access Journals (Sweden)

    Wen Yu

    2016-01-01

    Full Text Available A series of 2,2’-bipyrimidine-bridged dinuclear lanthanide complexes with the general formula [Ln(tmhd3]2bpm (tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionate, bpm = 2,2’-bipyrimidine, Ln = Gd(III, 1; Tb(III, 2; Dy(III, 3; Ho(III, 4 and Er(III, 5 has been synthesized and characterized. Sublimation of [Tb(tmhd3]2bpm onto a Au(111 surface leads to the formation of a homogeneous film with hexagonal pattern, which was studied by scanning tunneling microscopy (STM. The bulk magnetic properties of all complexes have been studied comprehensively. The dynamic magnetic behavior of the Dy(III and Er(III compounds clearly exhibits single molecule magnet (SMM characteristics with an energy barrier of 97 and 25 K, respectively. Moreover, micro-SQUID measurements on single crystals confirm their SMM behavior with the presence of hysteresis loops.

  17. Effect of annealing on the structural, optical and emissive properties of SrWO4:Ln(3+) (Dy(3+), Eu(3+) and Sm(3+)) nanoparticles.

    Science.gov (United States)

    Maheshwary; Singh, B P; Singh, R A

    2016-01-05

    Lanthanide ions, Ln(3+) (Dy(3+), Eu(3+) and Sm(3+)) doped SrWO4 nanoparticles were synthesized using ethylene glycol (EG) as a capping agent as well as reaction medium. The X-ray diffraction (XRD) study reveals that all the Ln(3+) (Dy(3+), Eu(3+) and Sm(3+)) doped samples are well crystalline in nature with a tetragonal scheelite structure of SrWO4 phase. TG study reveals that the nanophosphors are thermally stable. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy techniques were used to obtain the information about internal and external vibrational modes present in the SrWO4 structure. Optical properties were investigated using UV-vis and photoluminescence (PL) spectroscopy. The average crystallite size was calculated using Debye-Scherrer's for as-prepared and 800°C annealed samples and is found to be in the range of ∼35-70nm. The luminescence intensity of Eu(3+) doped SrWO4 nanoparticles under 364nm excitation wavelength reveals that (5)D0→(7)F2 transition at ∼613nm (red) is more prominent than that of (5)D0→(7)F1 transition at ∼590nm (orange). Also upon excitation by UV radiation, the SrWO4:Dy(3+) phosphor shows the yellow and blue transition lines appearing at ∼572 and 484nm which are the characteristic electronic transitions of (4)F9/2-(6)H13/2 and (4)F9/2-(6)H15/2 emission line of Dy(3+), respectively. Also Sm(3+) doped SrWO4 nanophosphor shows its characteristic emission lines in the range of 550-720nm, corresponding to (4)G5/2→(6)HJ (J=5/2, 7/2, 9/2 and 11/2) transitions of Sm(3+) ions. The predominant orange red color can be attributed to (4)G5/2→(6)H9/2 located at ∼642nm. This is related to the polarizing effect due to the energy transfer from WO4(2-) to the Eu(3+), Dy(3+) and Sm(3+) sites, respectively. Effect of annealing on the photoluminescence properties of samples has been studied and it was found that luminescence intensity increases up to ∼3 times on heating the samples at 800°C. This may be due to

  18. Kinematická analýza posturálních změn v bipedálním stoji při aplikaci podnětu ze zevního prostředí a modifikaci vizuální scény u pacientů po plastice předního zkříženého vazu Kinematic analysis of postural changes in bipedal stance at application of stimulus from external environment and modifi cation of visual scene in patients with anterior cruciate ligament reconstruction

    Directory of Open Access Journals (Sweden)

    Miroslav Janura

    2007-01-01

    Full Text Available Tato studie se zabývá změnami postury při modifikované zrakové scéně a při aplikaci podnětu ze zevního prostředí u zdravých jedinců a u pacientů po plastice předního zkříženého vazu (LCA za nezměněné a modifi kované vizuální scény. Do vyšetřovaného souboru bylo zahrnuto 11 pacientů po plastice LCA a 14 zdravých jedinců. Modifi kace vizuální scény bylo dosaženo prostřednictvím speciálního optického systému Olympus – Eye trek FMD-700. Zevní podnět byl realizován pomocí nárazu letícího míče. K hodnocení posturálních změn jsme využili kinematickou analýzu. U pacientů po rekonstrukci LCA i u zdravých jedinců jsme nejvíce diferencí v jednotlivých způsobech provedení nalezli pro kinematické parametry na dolních končetinách a trupu. U obou skupin probandů jsme zaznamenali podobné tendence k posturálním změnám. Při porovnávání kinematických parametrů mezi skupinou pacientů a zdravých jedinců jsme nalezli rozdíly v poloze horních končetin. Pro dolní končetiny a trup (s výjimkou minimální velikosti úhlu bérec – stehno při modifi kované scéně s reálným podnětem nejsou rozdíly mezi oběma skupinami statisticky významné. Tears and rupture of the anterior cruciate ligament (ACL, which has an important function in knee joint stability, are very common and more so in sports. ACL injury can be managed in two ways. One alternative pertains to conservative therapy whereas the second variant is surgical intervention (reconstruction. The number of ACL reconstructions has risen recently. The purpose of this study was to analyze the postural changes in bipedal stance at application of a stimulus from external environment and the resultant modifi cation in the visual scene in patients with ACL reconstruction. The examined group consisted of 25 subjects – 11 patients with ACL reconstruction and 14 healthy adults. The external stimulus was realized by striking

  19. Visible and near-infrared intense luminescence from water-soluble lanthanide [Tb(III), Eu(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), Er(III)] complexes.

    Science.gov (United States)

    Quici, Silvio; Cavazzini, Marco; Marzanni, Giovanni; Accorsi, Gianluca; Armaroli, Nicola; Ventura, Barbara; Barigelletti, Francesco

    2005-02-07

    The synthesis of a new ligand (1) containing a single phenanthroline (phen) chromophore and a flexibly connected diethylenetriamine tetracarboxylic acid unit (DTTA) as a lanthanide (Ln) coordination site is reported [1 is 4-[(9-methyl-1,10-phenantrol-2-yl)methyl]-1,4,7-triazaheptane-1,1,7,7-tetraacetic acid]. From 1, an extended series of water-soluble Ln.1 complexes was obtained, where Ln is Eu(III), Tb(III), Gd(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III). The stoichiometry for the association was found 1:1, with an association constant K(A) > or = 10(7) s(-1) as determined by employing luminescence spectroscopy. The luminescence and photophysical properties of the series of lanthanide complexes were investigated in both H2O and D2O solutions. High efficiencies for the sensitized emission, phi(se), in air-equilibrated water were observed for the Ln.1 complexes of Eu(III) and Tb(III) in the visible region (phi(se) = 0.24 and 0.15, respectively) and of Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III) in the vis and/or near-infrared region [phi(se) = 2.5 x 10(-3), 5 x 10(-4), 3 x 10(-5), 2 x 10(-5), 2 x 10(-4), 4 x 10(-5), and (in D2O) 4 x 10(-5), respectively]. For Eu.1 and Tb.1, luminescence data for water and deuterated water allowed us to estimate that no solvent molecules (q) are bound to the ion centers (q = 0). Luminescence quenching by oxygen was investigated in selected cases.

  20. Sociální síť Facebook jako efektivní nástroj firemní komunikace

    OpenAIRE

    Sénášiová, Hana

    2015-01-01

    Diplomová práce se zaměřuje na firemní komunikaci skrze sociální síť Facebook. Zabývá se propagací a úspěšností reklamních sdělení společnosti na fanouškovských stránkách. Výstupem jsou doporučení, jejichž následování může významně přispět k přidané hodnotě společnosti nejen ve formě zvýšení tržeb, ale také ke zvýšení povědomí o značce. The diploma thesis focuses on corporate communication through social network Facebook. It deals with the promotion and success of advertising communication...

  1. Dispersible crystalline nanobundles of YPO{sub 4} and Ln (Eu, Tb)-doped YPO{sub 4}: rapid synthesis, optical properties and bio-probe applications

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, Shafquat, E-mail: shafquatmajeed@gmail.com [Indian Institute of Science, Materials Research Centre (India); Bashir, Mohsin [Indian Institute of Science, Department of Molecular Reproduction, Development and Genetics (MRDG) (India); Shivashankar, S. A. [Indian Institute of Science, Materials Research Centre (India)

    2015-07-15

    Undoped and Ln{sup 3+} (Eu and Tb)-doped crystalline nanobundles of YPO{sub 4} were prepared by a facile microwave-assisted route with water as a solvent and without using any surfactant. TEM investigations reveal that the as-prepared powder consists of lenticular-shaped nanobundles (∼100 nm in diameter) made of very small nanorods with diameter less than 10 nm and length varying from 20 to 50 nm. Each nanorod in turn is single crystalline, as revealed by HRTEM imaging. The as-prepared nanobundles are easily dispersible in various solvents, especially water, without any surface functionalization, which is critical for various bio-probe applications like cell and tissue imaging. The Eu- and Tb-doped YPO{sub 4} nanobundles show good photoluminescence properties and were further evaluated for their use as fluorescent biolabels. Our results show that HeLa cells labelled with Eu- and Tb-doped YPO{sub 4} nanobundles show bright red (Eu) and green (Tb) intracellular luminescence under a confocal microscope. Concentration- and time-dependent MTT cell viability assays show that the nanobundles show low toxicity towards cells which makes them promising in bioimaging field.

  2. The 〈 ln A 〉 study with the Muon tracking detector in the KASCADE-Grande experiment – comparison of hadronic interaction models

    Directory of Open Access Journals (Sweden)

    Łuczak P.

    2015-01-01

    Full Text Available With the KASCADE-Grande Muon Tracking Detector it was possible to measure with high accuracy directions of EAS muons with energy above 0.8 GeV and up to 700 m distance from the shower centre. Reconstructed muon tracks allow investigation of muon pseudorapidity (η distributions. These distributions are nearly identical to the pseudorapidity distributions of their parent mesons produced in hadronic interactions. Comparison of the η distributions from measured and simulated showers can be used to test the quality of the high energy hadronic interaction models. The pseudorapidity distributions reflect the longitudinal development of EAS and, as such, are sensitive to the mass of the cosmic ray primary particles. With various parameters of the η distribution, obtained from the Muon Tracking Detector data, it is possible to calculate the average logarithm of mass of the primary cosmic ray particles. The results of the 〈 ln A 〉 analysis in the primary energy range 1016 eV–1017 eV with the 1st quartile and the mean value of the distributions will be presented for the QGSJet-II-2, QGSJet-II-4, EPOS 1.99 and EPOS LHC models in combination with the FLUKA model.

  3. Řízení cash flow při minimální ceně stavební zakázky

    OpenAIRE

    Šmýdová, Lucie

    2013-01-01

    Obsahem této diplomové práce je řízení cash flow při minimální ceně stavební zakázky „Intenzifikace čističky odpadních vod Sokolov – I. etapa“. Jsou zde srovnány dvě varianty řízení cash flow zakázky, které se liší smluvními podmínkami mezi stavebním podnikem a zhotovitelem subdodávky. V první variantě podnik požaduje splatnost faktur 90 dnů a zajištění záruk pomocí bankovní garance po subdodavateli. V další variantě subdodavatel poskytl podniku možnost využit 9% skonta při splatnosti faktur ...

  4. Effect of Multipass TIG and Activated TIG Welding Process on the Thermo-Mechanical Behavior of 316LN Stainless Steel Weld Joints

    Science.gov (United States)

    Ganesh, K. C.; Balasubramanian, K. R.; Vasudevan, M.; Vasantharaja, P.; Chandrasekhar, N.

    2016-04-01

    The primary objective of this work was to develop a finite element model to predict the thermo-mechanical behavior of an activated tungsten inert gas (ATIG)-welded joint. The ATIG-welded joint was fabricated using 10 mm thickness of 316LN stainless steel plates in a single pass. To distinguish the merits of ATIG welding process, it was compared with manual multipass tungsten inert gas (MPTIG)-welded joint. The ATIG-welded joint was fabricated with square butt edge configuration using an activating flux developed in-house. The MPTIG-welded joint was fabricated in thirteen passes with V-groove edge configuration. The finite element model was developed to predict the transient temperature, residual stress, and distortion of the welded joints. Also, microhardness, impact toughness, tensile strength, ferrite measurement, and microstructure were characterized. Since most of the recent publications of ATIG-welded joint was focused on the molten weld pool dynamics, this research work gives an insight on the thermo-mechanical behavior of ATIG-welded joint over MPTIG-welded joint.

  5. Optical, Structural and Paramagnetic Properties of Eu-Doped Ternary Sulfides ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y

    Directory of Open Access Journals (Sweden)

    Vítězslav Jarý

    2015-10-01

    Full Text Available Eu-doped ternary sulfides of general formula ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y are presented as a novel interesting material family which may find usage as X-ray phosphors or solid state white light emitting diode (LED lighting. Samples were synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their physical properties were investigated by means of X-ray diffraction, time-resolved photoluminescence spectroscopy, electron paramagnetic resonance, and X-ray excited fluorescence. Corresponding characteristics, including absorption, radioluminescence, photoluminescence excitation and emission spectra, and decay kinetics curves, were measured and evaluated in a broad temperature range (8–800 K. Calculations including quantum local crystal field potential and spin-Hamiltonian for a paramagnetic particle in D3d local symmetry and phenomenological model dealing with excited state dynamics were performed to explain the experimentally observed features. Based on the results, an energy diagram of lanthanide energy levels in KLuS2 is proposed. Color model xy-coordinates are used to compare effects of dopants on the resulting spectrum. The application potential of the mentioned compounds in the field of white LED solid state lighting or X-ray phosphors is thoroughly discussed.

  6. Controllable syntheses of porous metal-organic frameworks: encapsulation of Ln(III) cations for tunable luminescence and small drug molecules for efficient delivery.

    Science.gov (United States)

    Wang, Yun; Yang, Jin; Liu, Ying-Ying; Ma, Jian-Fang

    2013-10-18

    Two porous metal-organic frameworks (MOFs), [Zn3 (L)(H2 O)2 ]⋅3 DMF⋅7 H2 O (MOF-1) and [(CH3 )2 NH2 ]6 [Ni3 (L)2 (H2 O)6 ]⋅3 DMF⋅15 H2 O (MOF-2), were synthesized solvothermally (H6 L=1,2,3,4,5,6-hexakis(3-carboxyphenyloxymethylene)benzene). In MOF-1, neighboring Zn(II) trimers are linked by the backbones of L ligands to form a fascinating 3D six-connected framework with the point symbol (4(12) .6(3) ) (4(12) .6(3) ). In MOF-2, eight L ligands bridge six Ni(II) atoms to generate a rhombic-dodecahedral [Ni6 L8 ] cage. Each cage is surrounded by eight adjacent ones through sharing of carboxylate groups to yield an unusual 3D porous framework. Encapsulation of Ln(III) cations for tunable luminescence and small drug molecules for efficient delivery were investigated in detail for MOF-1. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Crystal chemical study of a series of rare earth fluorinated compounds with formula LiNaLn/sub 2/F/sub 8/ and evidence for the participation of 4 f orbitals in bonding

    Energy Technology Data Exchange (ETDEWEB)

    Zambon, D.; Metin, J.; Picaud, B.; Avignant, D.

    1985-11-28

    A number of rare earth fluorides with formula LiNaLn/sub 2/F/sub 8/ (Ln=Ho, Er, Tm, Yb, Lu) have been synthesized. Their crystal chemical characteristics have been determined by analogy with the isostructural fluoride LiNaY/sub 2/F/sub 8/ which crystallizes in the monoclinic system with P2/sub 1//m space group and unit cell parameters: a=6.622 A, b=6.995 A, c=6.632 A and ..beta..=103/sup 0/14. The position of yttrium in comparison with the lanthanides family has been determined from the variation of the unit cell volume in the series. These results indicate that a certain degree of covalency due to the participation of 4f orbitals to bonding is present in these compounds with predominant ionic character.

  8. Katetrová ablace pro fibrilaci síní a spektrální analýza variability srdeční frekvence Catheter ablation for atrial fibrillation and spectral analysis of heart rate variability

    OpenAIRE

    Esseid Gaddur; Michal Botek; Filip Pavlík; Iva Řehová; Martin Fiala; Aleš Jakubec; Pavel Stejskal; Eva Vlčková

    2005-01-01

    Cílem studie bylo zkoumání vlivu katetrové ablace na parametry spektrální analýzy (SA) variability srdeční frekvence (HRV). Krátkodobý záznam SA HRV byl snímán u skupiny 22 pacientů s paroxysmální fibrilací síní (FS) ve věku 53,69 ± 11,95 let (20 mužů a 2 ženy), u kterých byla provedena cirkumferenční katetrová ablace (KA). Měření pro...

  9. Síntese, caracterização e propriedades espectroscópicas de criptatos de lantanídeo do tipo [LnÌ(bipy2py(CO2Et 23+

    Directory of Open Access Journals (Sweden)

    Nova Suzana P. Vila

    2004-01-01

    Full Text Available This work reports on the synthesis, characterization (infrared and hidrogen nmr spectra and photophysical properties (luminescence spectra and emission quantum yield of the lanthanide cryptates [LnÌ(bipy2py(CO2Et 2]3+ with Ln = Eu3+, Tb3+ or Gd3+, which can be applied as efficient Light-Conversion-Molecular-Devices. From emission spectra of [EuÌ(bipy2py(CO2Et 2]3+ it was possible to assign C3 symmetry to the metal ion. The spectroscopic studies show a higher emission quantum yield (q=25% for [TbÌ(bipy2py(CO2Et 2]3+ in aqueous solution, whereas the europium cryptate presents q=14%. This is justified by a more efficient energy transfer between triplet and emission levels of terbium (T->5D4.

  10. Formation of polymeric assemblies of six-coordinate metal complexes with mixed bridges of dicarboxylato-azido moieties

    Directory of Open Access Journals (Sweden)

    Riyadh M. Ahmed

    2014-12-01

    Full Text Available New biscarboxylato zwitterionic ligands, namely bis(N-carboxylatoethyl-4,4′-dipyridinum L1 and bis(N-carboxylatopropyl--4,4′-dipyridinum L2, were synthesized from the reaction of 4,4′-dipyridine with 3-bromopropanoic acid and 4-bromobutanoic acid, respectively. The reaction of these ligands and the azido coligand with some metal ions resulted in the formation of polymeric complexes of general formulae [Cr2(Ln(N34]Cl2·H2O and [M2(Ln(N34] xH2O, where (M=Mn (II, Fe(II, Co(II, Ni(II, Cu(II, Zn(II and Cd(II; n=1, 2; x=1, 1, 1, 1, 0, 1, and 1, respectively. The oxygens of the carboxylato group are coordinated to the metal ion in a bidentate fashion. The mode of bonding and overall geometry of the complexes were determined through IR, UV–VIS, NMR and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, chloride content and conductance. These studies revealed the formation of polymeric assemblies of six-coordinate complexes with distorted octahedral geometries about metal centers.

  11. Evaluace vzdělávací výstavy o globálních problémech a spotřebitelské odpovědnosti: od zaujetí k bezmoci

    Directory of Open Access Journals (Sweden)

    Jan Činčera

    2013-09-01

    Full Text Available Článek prezentuje evaluaci interaktivní výstavy určené pro středoškolské studenty (věk 15–19 let, která se zaměřuje na globální problémy a spotřebitelskou odpovědnost. Evaluace byla provedena na třech školách. Data byla získána rozhovory s učiteli (N=3 a dotazníky rozdanými studentům po konci výstavy (N=204. K analýze dat byly použity jak kvantitativní tak kvalitativní přístupy.Výsledky naznačují, že výstava studenty zaujala a zvýšila jejich povědomí o globálních problémech, někteří ji ale hodnotili jako manipulativní. Nežádoucím efektem výstavy pak byl pocit bezmoci reflektovaný některými studenty. Článek diskutuje zjištěné poznatky a navrhuje změnu strategie pro výuku globální problematiky.

  12. Altered rocks of the Onguren carbonatite complex in the Western Tansbaikal Region: Geochemistry and composition of accessory minerals

    Science.gov (United States)

    Savelyeva, V. B.; Bazarova, E. P.; Sharygin, V. V.; Karmanov, N. S.; Kanakin, S. V.

    2017-07-01

    The paper discusses the mineralogy and geochemistry of altered rocks associated with calcite and dolomite-ankerite carbonatites of the Onguren dyke-vein complex in the Western Transbaikal Region. The alteration processes in the Early Proterozoic metamorphic complex and synmetamorphic granite hosting carbonatite are areal microclinization and riebeckitization; carbonates, phlogopite, apatite, and aegirine occur in the near-contact zones of the dolomite-ankerite carbonatite veins; and silicification is displayed within separated zones adjacent to the veins. In aluminosilicate rocks, microclinization was accompanied by an increasing content of K, Fe3+, Ti, Nb (up to 460 ppm), Th, Cu, and REE; Na, Ti, Fe3+, Mg, Nb (up to 1500 ppm), Zr (up to 2800 ppm), Ta, Th, Hf, and REE accumulated in the inner zone of the riebeckitization column. High contents of Ln Ce (up to 11200 ppm), U (23 ppm), Sr (up to 7000 ppm), Li (up to 400 ppm), Zn (up to 600 ppm), and Th (up to 700 ppm) are typical of apatite-phlogopite-riebeckite altered rock; silicified rock contains up to (ppm): 2000 Th, 20 U, 13000 Ln Ce, and 5000 Ba. Ilmenite and later rutile are the major Nb carriers in alkali altered rocks. These minerals contain up to 2 and 7 wt % Nb2O5, respectively. In addition, ferrocolumbite and aeschynite-(Ce) occur in microcline and riebeckite altered rocks. Fluorapatite containing up to 2.7 wt % ( Ln Ce)2O3, monazite-(Ce), cerite-(Ce), ferriallanite-(Ce), and aeschynite-(Ce) are the REE carriers in riebeckite altered rock. Bastnäsite-(Ce), rhabdophane-group minerals, and xenotime-(Y) are typical of silicified rock. Thorite, monazite-(Ce), and rhabdophane-group minerals are the Th carriers.

  13. Low-complexity blind equalization for OFDM systems with general constellations

    KAUST Repository

    Al-Naffouri, Tareq Y.

    2012-12-01

    This paper proposes a low-complexity algorithm for blind equalization of data in orthogonal frequency division multiplexing (OFDM)-based wireless systems with general constellations. The proposed algorithm is able to recover the transmitted data even when the channel changes on a symbol-by-symbol basis, making it suitable for fast fading channels. The proposed algorithm does not require any statistical information about the channel and thus does not suffer from latency normally associated with blind methods. The paper demonstrates how to reduce the complexity of the algorithm, which becomes especially low at high signal-to-noise ratio (SNR). Specifically, it is shown that in the high SNR regime, the number of operations is of the order O(LN), where L is the cyclic prefix length and N is the total number of subcarriers. Simulation results confirm the favorable performance of the proposed algorithm. © 2012 IEEE.

  14. Synthesis, spectroscopic, thermal and antimicrobial studies of neodymium(III) and samarium(III) complexes derived from tetradentate ligands containing N and S donor atoms

    Science.gov (United States)

    Ain, Qurratul; Pandey, S. K.; Pandey, O. P.; Sengupta, S. K.

    2015-04-01

    Trivalent lanthanide complexes of the type [Ln(L)Cl(H2O)2] (where Ln = Nd(III) or Sm(III) and LH2 = Schiff bases derived by the condensation of 3-(phenyl/substitutedphenyl)-4-amino-5-mercapto-1,2,4-triazole with diacetyl/benzil) have been synthesized by the reactions of anhydrous lanthanide(III) chloride with Schiff bases in methanol. The structures of the complexes have been proposed on the basis of elemental analysis, electrical conductance, magnetic moment, spectroscopic measurements (IR, 1H, 13C NMR and UV-vis spectra) and X-ray diffraction studies. The spectral data reveal that the Schiff base ligands behave as dibasic tetradentate chelating agents having coordination sites at two thiol sulfur atoms and two azomethine nitrogen atoms. The presence of coordinated water in metal complexes was confirmed by thermal and IR data of the complexes. All the Schiff bases and their metal complexes have also been screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus and antifungal activities against Aspergillus niger, Curvularia pallescens and Colletotrichum capsici.

  15. Synthesis, crystal structure, fluorescent and antioxidation properties of cerium(III) and europium(III) complexes with bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xia; Shi, Xinkui; Xu, Yuling; Shen, Kesheng; Mao, Shanshan; Wu, Huilu [School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Gansu (China)

    2017-03-02

    Two aliphatic ether Schiff base lanthanide complexes (Ln = Eu, Ce) with bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine (Bod), were synthesized and characterized by physicochemical and spectroscopic methods. [Eu(Bod)(NO{sub 3}){sub 3}] (1) is a discrete mononuclear species and [Ce(Bod)(NO{sub 3}){sub 3}DMF]{sub ∞} (2) exhibits an inorganic coordination polymer. In the two complexes, the metal ions both are ten-coordinated and the geometric structure around the Ln{sup III} atom can be described as distorted hexadecahedron. Under excitation at room temperature, the red shift in the fluorescence band of the ligand in the complexes compared with that of the free ligand can be attributed to coordination of the rare earth ions to the ligand. Moreover, the antioxidant activities of the two complexes were investigated. The results demonstrated that the complexes have better scavenging activity than both the ligand and the usual antioxidants on the hydroxyl and superoxide radicals. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Účinek osmitýdenního plicního rehabilitačního programu na hrudní mobilitu a maximální vdechový a výdechový ústní tlak u pacientů s bronchiálním astmatem The effect of 8 week pulmonary rehabilitation programme on chest mobility and maximal inspiratory and expiratory mouth pressure in patients with bronchial asthma

    Directory of Open Access Journals (Sweden)

    Ivan Vařeka

    2008-04-01

    Full Text Available U nemocných s bronchiálním astmatem se mohou vyskytovat nejen poruchy dýchání, ale také muskuloskeletální poruchy. Poruchy dýchání a muskuloskeletální poruchy mohou vést k dalším zdravotním problémům a mohou tak snižovat kvalitu života. Tyto poruchy mohou být také spojeny s psychosociálními problémy a mohou mít vliv na omezení různých aktivit nemocných (pohybové aktivity, sportování, běžné denní aktivity – nakupování, uklízení atd.. Mezi nejvíce omezující symptomy u nemocných s bronchiálním astmatem patří ztížené dýchání a kašel. Komprehensivní léčba je založena nejen na farmakoterapii, ale také na nemedikamentózní léčbě, jejíž důležitou součástí je respirační fyzioterapie. Pro účinek rehabilitační léčby je ale nutné správné nastavení farmakoterapie. Cílem této studie bylo zjistit, zda program plicní rehabilitace ovlivní hodnoty maximálních nádechových a výdechových ústních tlaků a rozvíjení hrudníku u nemocných s bronchiálním astmatem. Výzkumný soubor byl tvořen 23 nemocnými s bronchiálním astmatem, kteří absolvovali osmitýdenní program plicní rehabilitace (30minutová terapie dvakrát týdně. Jednalo se o pacienty s intermitentním lehkým stádiem bronchiálního astmatu beze změn ve farmakoterapii. Program plicní rehabilitace byl zaměřen na dechová cvičení (aktivace bráničního dýchání, aktivace výdechu, nácvik efektivní expektorace atd. a techniky měkkých tkání s cílem uvolnění svalů a fascií v oblasti hrudního koše a pletence ramenního. Na začátku a konci osmitýdenního programu plicní rehabilitace byly vyšetřeny maximální nádechové a výdechové ústní tlaky a rozvíjení hrudníku. Rozvíjení hrudníku bylo hodnoceno ve dvou úrovních – mezosternální a xiphosternální. Po absolvování osmitýdenního programu plicní rehabilitace bylo zaznamenáno zlepšení rozv

  17. Reflections on the 22nd Conference of the African Studies Association in Germany (VAD e.V. in Cologne, Germany (30 May–2 June 2012 Reflexionen zur 22. Tagung der Vereinigung für Afrikawissenschaften in Deutschland (VAD e.V. in Köln (30. Mai bis 2. Juni 2012

    Directory of Open Access Journals (Sweden)

    Martina Gockel-Frank

    2013-01-01

    Full Text Available The following article comments on contents and organisation of the 22nd Conference of the African Studies Association in Germany (Vereinigung für Afrikawissenschaften in Deutschland, VAD e.V., which took place from 30 May until 2 June 2012 at the University of Cologne, Germany. Thirty-seven panels and five round tables organised around four thematic foci (land rights, resource management, models of governance, media served as a platform for discussions on developments on the African continent. A complex framework programme dealing with similar topics was open to the public and provided insight into recent research projects and their results.Die Autoren berichten über inhaltliche Schwerpunkte und Ablauf der 22. Tagung der Vereinigung für Afrikawissenschaften in Deutschland (VAD e.V., die vom 30. Mai bis zum 2. Juni 2012 an der Universität zu Köln stattfand. Vier Themenkomplexe (Landrechte, Ressourcennutzung, Regierungsformen und neue Medien wurden in 37 Vortrags- und Diskussionsforen sowie fünf Round-Table-Gesprächen diskutiert. Im Rahmen eines thematisch angepassten umfassenden Rahmenprogramms konnte sich eine interessierte Öffentlichkeit über aktuelle Forschungsprojekte und deren Ergebnisse informieren.

  18. Synthesis, crystal structures, and properties of oxovanadium(IV)-lanthanide(III) heteronuclear complexes.

    Science.gov (United States)

    Shi, Wei; Chen, Xiao-Yan; Zhao, Yan-Nan; Zhao, Bin; Cheng, Peng; Yu, Ao; Song, Hai-Bin; Wang, Hong-Gen; Liao, Dai-Zheng; Yan, Shi-Ping; Jiang, Zong-Hui

    2005-08-19

    A new series of oxovanadium(IV)-lanthanide(III) heteronuclear complexes [Yb(H2O)8]2[(VO)2(TTHA)](3)21 H2O (1), {[Ho(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)} 8.5 H2O (2), {[Gd(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)}8.5 H2O (3), {[Eu(H2O)7][(VO)2(TTHA)](1.5)} 10.5 H2O (4), and [Pr2(H2O)6(SO4)2][(VO)2(TTHA)] (5) (H6TTHA=triethylenetetraaminehexaacetic acid) were prepared by using the bulky flexible organic acid H(6)TTHA as structure-directing agent. X-ray crystallographic studies reveal that they contain the same [(VO)2(TTHA)]2- unit as building block, but the Ln3+ ion lies in different coordination environments. Although the lanthanide ions always exhibit similar chemical behavior, the structures of the complexes are not homologous. Compound 1 is composed of a [Yb(H2O)8]3+ ion and a [(VO)2(TTHA)]2- ion. Compounds 2 and 3 are isomorphous; both contain a trinuclear [Ln(H2O)7(VO)2(TTHA)]+ (Ln=Ho for 2 and Gd for 3) ion and a [(VO)2(TTHA)]2- ion. Compound 4 is an extended one-dimensional chain, in which each Eu3+ ion links two [(VO)2(TTHA)]2- ions. For 5, the structure is further assembled into a three-dimensional network with an interesting framework topology comprising V2Pr2 and V4Pr2 heterometallic lattices. Moreover, 4 and 5 are the first oxovanadium(IV)-lanthanide(III) coordination polymers and thus enlarge the realm of 3d-4f complexes. The IR, UV/Vis, and EPR spectra and the magnetic properties of the heterometallic complexes were studied. Notably, 2 shows unusual ferromagnetic interactions between the VO2+ and Ho3+ ions.

  19. Sonochemical synthesis and DFT studies of nano novel Schiff base cadmium complexes: Green, efficient, recyclable catalysts and precursors of Cd NPs

    Science.gov (United States)

    Parsaee, Zohreh

    2017-10-01

    Novel asymmetric (N4) Schiff bases (Ln, n = 1-3) and their nanosized cadmium complexes derived of 4,4'-(pentylazanediyl) dibenzaldehyde and aminobenzaldehyde are synthesized by sonochemical method and characterized based on physicochemical analysis including 1H NMR, 13C NMR, SEM, TGA, Mass, FT-IR, UV-Vis spectroscopy, elemental analysis, magnetic moment and molar conductance measurements. According to the analytic results of the NMR, UV-Vis and magnetic moment studies, it is found that the geometrical structures of these complexes [CdII2LnCl4], (L = C45H40N5X, X = CH3, Cl, OH) are square planer. The synthesized complexes were so effective as nanocatalyst on the oxidation of primary and secondary alcohols. The oxidation reactions were carried out in ethyl-methyl-imidazolium ionic liquid in presence of NaOCl. In addition Cd NPs were synthesized through the thermal decomposition of mentioned complexes and characterized by using FT-IR, SEM, TEM, EDX and XRD methods, which indicated close accordance to the standard pattern of CdO nanoparticles and an acceptable size at the nanorange (22-27 nm). Furthermore geometrical optimization of the Cd2LnCl4 calculated using DFT/B3LYP with LanL2DZ/6-311+G (d,p) level. The electronic parameter including HOMO-LUMO orbitals, bond gap, chemical hardness-softness, electronegativity, electrophilicity, NMR chemical shifts and IR frequencies were calculated. The calculated NMR shifts and vibrational frequencies showed excellent agreement with experimental data.

  20. The role of the enzyme alpha-amylase in binding of An(III)/Ln(III) by oral ingestion

    Energy Technology Data Exchange (ETDEWEB)

    Barkleit, A.; Bernhard, G. [Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Division of Radiochemistry and Resource Ecology, Technische Universitaet Dresden, 01062 Dresden (Germany); Heller, A. [Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)

    2014-07-01

    In case of incorporation, radionuclides represent a serious health risk to humans due to their (radio-)toxicity. Thus, the determination of their speciation and transport on a molecular level is crucial for the understanding of the transport, metabolism, deposition and elimination in the human organisms. In case of oral ingestion of contaminated food or radioactive substances the first contact medium in the mouth is the aqueous bio-fluid saliva which contains inorganic ions (mainly Na{sup +}, K{sup +}, Ca{sup 2+}, Cl{sup -}, CO{sub 3}{sup 2-}, PO{sub 4}{sup 3-}) and numerous biomolecules, mainly proteins. One of the major proteins in saliva is the digestive enzyme α-amylase which catalyzes the hydrolysis of the α-1,4 glycosidic linkages of polysaccharides like starch or glycogen. [1] In this study the speciation of curium(III) and europium(III) in saliva as the first contact medium at oral incorporation was investigated with time-resolved laser-induced fluorescence spectroscopy (TRLFS). For TRLFS measurements, fresh saliva samples from human sources have been spiked in vitro with Eu(III) or Cm(III). The identification of the dominant species was achieved by a comparison of the spectroscopic data with reference spectra obtained from synthetic saliva and the main single components of the bio-fluid. In the pH range from 6.8 to 7.4 similar spectra were obtained. With respect to reference data, the spectra indicate the formation of a ternary metal complex containing phosphate and carbonate anions and, in addition, a coordination of organic matter, namely α-amylase, to the central metal cation is suggested. To get more information about the binding behavior of α-amylase various investigations with Eu(III) as inactive analog for An(III) were carried out with porcine pancreatic α-amylase (PPA) which serves as model system for various α-amylase species. Sorption experiments showed a high affinity of Eu(III) to α-amylase in a wide pH range, namely between pH 4 and 8

  1. Thermal and spectroscopic studies on solid ibuprofen complexes of lighter trivalent lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Gálico, D.A.; Holanda, B.B.C.; Guerra, R.B.; Legendre, A.O.; Rinaldo, D. [UNESP – Univ Estadual Paulista, Faculdade de Ciências, Departamento de Química, São Paulo CEP 17033-260 (Brazil); Treu-Filho, O. [UNESP – Univ Estadual Paulista, Instituto de Química, São Paulo CEP 14800-900 (Brazil); Bannach, G., E-mail: gilbert@fc.unesp.br [UNESP – Univ Estadual Paulista, Faculdade de Ciências, Departamento de Química, São Paulo CEP 17033-260 (Brazil)

    2014-01-10

    Highlights: • Lighter trivalent lanthanide complexes of ibuprofen have been synthesized. • The TG-FTIR allowed the identification of propane as the gas evolved during the thermal decomposition of the neodymium compound. • The thermal analysis provided information about the composition, dehydration, thermal behavior and thermal decomposition of the samples. • The theoretical and experimental spectroscopic studies suggest that the carboxylate group of ibuprofen is coordinated to the metals by a bidentate bond. - Abstract: Solid-state compounds of general formula Ln(L){sub 3}, in which L is ibuprofen and Ln stands for trivalent La, Ce, Pr, Nd, Sm and Eu, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry (DRX), complexometry, Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetry coupled to Fourier-transformed infrared spectroscopy (TG-FTIR) were used to characterize these compounds. The results provided information concerning the chemical composition, dehydration, coordination modes of the ligands, crystallinity of the samples, thermal behavior and thermal decomposition of the compounds. The theoretical and experimental spectroscopic studies suggest that ibuprofen coordinates through the carboxylate group as a chelating ligand.

  2. Synthesis and molecular structures of hydrotris(dimethylpyrazolyl)borate complexes of the lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Liu, S.Y.; Maunder, G.H.; Sella, A. [Christopher Ingold Labs., London (United Kingdom)] [and others

    1996-01-03

    The reaction of lanthanide triflates with 2 equiv of potassium hydrotris(dimethylpyrazoly)borate (Tp{sup Me}{sub 2}) gives good yields of complexes of composition Ln(Tp{sup Me}{sub 2})OTf. For La (2), Ce (3), Pr (4), and Nd (5) the complexes are seven-coordinate in the solid state with the triflate group coordinated to the metal in unidentate fashion. Complex 5 crystallizes in the monoclinic space group P2/c with a = 17.629(3) {angstrom}, b = 12.740(2) {angstrom}, c = 18.163(3) {angstrom}, {beta} = 107.34(1){degrees}, V = 3893(1) {angstrom}{sup 3}, Z = 4, and R{sub w} = 0.0458. For the complexes of Y (1), Sm (6), Eu (7), Gd (8), Dy (9), Ho (10), and Yb (11), the smaller size of the metal ion leads to ejection of the triflate from the coordination sphere and the complexes are ionic in the solid state with a six-coordinate metal center. Complex 11 crystallizes in the monoclinic space group C2/m with a = 16.593(7) {angstrom}, b = 13.671(5) {angstrom}, c = 8.746(2) {angstrom}, {beta} = 91.66(3){degrees}, V = 1983(1) {angstrom}{sup 3}, Z = 2, and R{sub w} = 0.0416. In solution, however, complex 6 adopts a seven-coordinate molecular structure with the triflate ion within the first coordination sphere.

  3. Complex analysis and geometry

    CERN Document Server

    Silva, Alessandro

    1993-01-01

    The papers in this wide-ranging collection report on the results of investigations from a number of linked disciplines, including complex algebraic geometry, complex analytic geometry of manifolds and spaces, and complex differential geometry.

  4. Manganese-Schiff base complexes as catalysts for water photolysis.

    Science.gov (United States)

    González-Riopedre, Gustavo; Fernández-García, M Isabel; González-Noya, Ana M; Vázquez-Fernández, M Ángeles; Bermejo, Manuel R; Maneiro, Marcelino

    2011-10-28

    Four manganese(III)-Schiff base complexes (1-4) of formula [MnL(n)(H(2)O)(2)](2)(ClO(4))(2)·mH(2)O (n = 1-4; m = 0, 1) have been prepared. The multidentate H(2)L(n) Schiff base ligands consist of 3R,5R-substituted N,N'-bis(salicylidene)-1,2-diimino-2,2-dimethylethane, where R = OEt, OMe, Br or Cl. The complexes have been thoroughly characterized by elemental analysis, mass spectrometry, magnetic susceptibility measurements, IR, UV, paramagnetic (1)H NMR and EPR spectroscopies. Other properties, including redox studies and molar conductivity measurements, have also been assessed. The crystal structure of 1 was solved by X-ray diffraction, which revealed the dimeric nature of the compound through μ-aqua bridges. The ability of these complexes to split water has been studied by water photolysis experiments, with the oxygen evolution measured in aqueous media in the presence of a hydrogen acceptor (p-benzoquinone), the reduction of which was followed by UV-spectroscopy. The discussion of the photolytic behaviour includes advances in the knowledge of the structural motifs and the chemical activity of this type of complex, as revealed by the development of several characterization techniques in the last decade. Parallel-mode Mn(III) EPR shows that complexes 1-4 not only mimic reactivity but also share some structural characteristics from partially assembled natural OEC clusters. This journal is © the Owner Societies 2011

  5. Scandium SALEN complexes bearing chloro, aryloxo, and hydroxo ligands.

    Science.gov (United States)

    Meermann, Christian; Törnroos, Karl W; Anwander, Reiner

    2009-03-16

    Heteroleptic amide complexes (SALEN)Sc[N(SiHMe(2))(2)] (SALEN = Salen(tBu,tBu), Salcyc(tBu,tBu), or Salpren(tBu,tBu) if not stated differently) were examined as synthesis precursors according to silylamine elimination reactions. Treatment of (SALEN)Sc[N(SiHMe(2))(2)] with H(2)O or phenols (HOAr(R,R); R = tBu, iPr) afforded complexes [(SALEN)Sc(mu-OH)](2) and (SALEN)Sc(OAr(R,R)), while chloro exchange products were formed from the respective reactions with NH(4)Cl or AlMe(2)Cl. Such complexes [(SALEN)Sc(mu-Cl)](2) and (SALEN)ScCl(thf) were also obtained by utilizing alternative synthesis protocols, allowing for controlled donor absence and presence. Heteroleptic amide precursors [Sc(NiPr(2))(2)(mu-Cl)(thf)](2) and [Sc[N(SiHMe(2))(2)](2)(mu-Cl)(thf)](2) readily undergo amine elimination reactions with H(2)SALEN derivatives to form the corresponding chloride complexes. Spectroscopic and X-ray structural data of the heteroleptic scandium complexes revealed an exclusive intramolecular tetradentate coordination mode of the SALEN ligands independent of the SALEN ligand bite angle and the nature of the "second" ligand (chloro, amido, aryloxo, hydroxo). The coordination of the SALEN ligands is rationalized on the basis of (a) the displacement d of the metal center from the [N(2)O(2)] least-squares plane, (b) the dihedral angle alpha between the phenyl rings of the salicylidene moieties, and (c) the angle beta = Ct-Ln-Ct (Ct = centroid of the phenyl rings) in the case of strongly twisted ligands.

  6. Luminescent properties of heterotrinuclear 3d-4f complexes constructed from a naphthalenediol-based acyclic bis(salamo)-type ligand

    Science.gov (United States)

    Dong, Wen-Kui; Zheng, Shan-Shan; Zhang, Jin-Tong; Zhang, Yang; Sun, Yin-Xia

    2017-09-01

    Heterotrinuclear 3d-4f complexes with a naphthalenediol-based acyclic bis(salamo)-type ligand have been synthesized and structurally characterized. Spectral titrations clearly show that the heterotrinuclear complexes [Zn2(L)La(OAc)3] (1), [Zn2(L)Ce(OAc)3] (2) and [Zn2(L)Dy(OAc)3(CH3OH)]·CH2Cl2 (3) are acquired by the substitution reaction of the obtained homotrinuclear Zn(II) complex with 1 equiv. of Ln(NO3)3 (Ln3 + = La3 +, Ce3 + and Dy3 +). Two Zn(II) ions are penta- and hexa-coordinated with geometries of distorted tetragonal pyramid and octahedron. La(III) ion is deca-coordinated, adopting a distorted bicapped square antiprism geometry. Ce(III) ion is nona-coordinated with geometry of distorted capped square antiprism as well as Dy(III) ion. The different coordination modes of acetate ions in complexes 1, 2 and 3 lead to different coordination numbers of the lanthanide(III) ions. Furthermore, the structures and fluorescence properties have been discussed.

  7. Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Ka King [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    A series of organometallic compounds containing the tris(dimethylsilyl)methyl ligand are described. The potassium carbanions KC(SiHMe2)3 and KC(SiHMe2})3TMEDA are synthesized by deprotonation of the hydrocarbon HC(SiHMe2)3 with potassium benzyl. KC(SiHMe2)3TMEDA crystallizes as a dimer with two types of three-center-two-electron KH- Si interactions. Homoleptic Ln(III) tris(silylalkyl) complexes containing β-SiH groups M{C(SiHMe2)3}3 (Ln = Y, Lu, La) are synthesized from salt elimination of the corresponding lanthanide halide and 3 equiv. of KC(SiHMe2)3. The related reactions with Sc yield bis(silylalkyl) ate-complexes containing either LiCl or KCl. The divalent calcium and ytterbium compounds M{C(SiHMe2)3}2L (M = Ca, Yb; L = THF2 or TMEDA) are prepared from MI2 and 2 equiv of KC(SiHMe2)3. The compounds M{C(SiHMe2)3}2L (M = Ca, Yb; L = THF2 or TMEDA) and La{C(SiHMe2)3}3 react with 1 equiv of B(C6F5)3 to give 1,3- disilacyclobutane {Me2Si-C(SiHMe2)2}2 and MC(SiHMe2)3HB(C6F5)3L, and La{C(SiHMe2)3}2HB(C6F5)3, respectively. The corresponding reactions of Ln{C(SiHMe2)3}3 (Ln = Y, Lu) give the β-SiH abstraction product [{(Me2HSi)3C}2LnC(SiHMe2)2SiMe2][HB(C6F5)3] (Ln = Y, Lu), but the silene remains associated with the Y or Lu center. The abstraction reactions of M{C(SiHMe2)3}2L (M = Ca, Yb; L = THF2or TMEDA) and Ln{C(SiHMe2)3}3 (Ln = Y, Lu, La) and 2 equiv of B(C6

  8. Highly emitting near-infrared lanthanide "encapsulated sandwich" metallacrown complexes with excitation shifted toward lower energy.

    Science.gov (United States)

    Trivedi, Evan R; Eliseeva, Svetlana V; Jankolovits, Joseph; Olmstead, Marilyn M; Petoud, Stéphane; Pecoraro, Vincent L

    2014-01-29

    Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+ [12-MC(Zn(II),quinHA)-4]2[24-MC(Zn(II),quinHA)-8] (Ln3+ [Zn(II)MC(quinHA)]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+ [Zn(II)MC(quinHA)] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLn(L) = 2.88(2)%, τobs = 150.7(2) μs; Nd3+, QLn(L) = 1.35(1)%, τobs = 4.11(3) μs; Er3+, QLn(L) = 3.60(6)·10–2%, τobs = 11.40(3) μs), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties.

  9. Characterizing the magnetic susceptibility tensor of lanthanide-containing polymethylated-DOTA complexes

    Energy Technology Data Exchange (ETDEWEB)

    Strickland, Madeleine [National Institutes of Health, Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (United States); Schwieters, Charles D. [National Institutes of Health, Office of Intramural Research, Center for Information Technology (United States); Göbl, Christoph [Technische Universität München, Department of Chemistry (Germany); Opina, Ana C. L. [National Institutes of Health, Imaging Probe Development Center, National Heart, Lung, and Blood Institute (United States); Strub, Marie-Paule [National Institutes of Health, Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (United States); Swenson, Rolf E.; Vasalatiy, Olga [National Institutes of Health, Imaging Probe Development Center, National Heart, Lung, and Blood Institute (United States); Tjandra, Nico, E-mail: tjandran@nhlbi.nih.gov [National Institutes of Health, Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (United States)

    2016-10-15

    Lanthanide complexes based on the DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) cage are commonly used as phase contrast agents in magnetic resonance imaging, but can also be utilized in structural NMR applications due to their ability to induce either paramagnetic relaxation enhancement or a pseudocontact shift (PCS) depending on the choice of the lanthanide. The size and sign of the PCS for any given atom is determined by its coordinates relative to the metal center, and the characteristics of the lanthanide’s magnetic susceptibility tensor. Using a polymethylated DOTA tag (Ln-M8-SPy) conjugated to ubiquitin, we calculated the position of the metal center and characterized the susceptibility tensor for a number of lanthanides (dysprosium, thulium, and ytterbium) under a range of pH and temperature conditions. We found that there was a difference in temperature sensitivity for each of the complexes studied, which depended on the size of the lanthanide ion as well as the isomeric state of the cage. Using {sup 17}O-NMR, we confirmed that the temperature sensitivity of the compounds was enhanced by the presence of an apically bound water molecule. Since amide-containing lanthanide complexes are known to be pH sensitive and can be used as probes of physiological pH, we also investigated the effect of pH on the Ln-M8-SPy susceptibility tensor, but we found that the changes in this pH range (5.0–7.4) were not significant.

  10. The oxonitridoborate Eu{sub 5}(BO{sub 2.51(7)}N{sub 0.49(7)}){sub 4} and the mixed-valent borates Sr{sub 3}Ln{sub 2}(BO{sub 3}){sub 4} (Ln = Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Hoeppe, Henning A.; Kazmierczak, Karolina; Grumbt, Christine; Schindler, Lisa [Institut fuer Physik, Universitaet Augsburg (Germany); Schellenberg, Inga; Poettgen, Rainer [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Anorganische und Analytische Chemie (Germany)

    2013-11-04

    The crystal structures of the mixed borates Sr{sub 3}Er{sub 2}(BO{sub 3}){sub 4} [Pnma, no. 62, Z = 4, a = 738.08(2), b = 1588.94(4), c = 867.81(2) pm, 683 reflections, 70 parameters, R1 = 0.037, wR2 = 0.077] and Sr{sub 3}Ho{sub 2}(BO{sub 3}){sub 4} [Pnma, no. 62, Z = 4, a = 738.45(7), b = 1591.55(12), c = 871.03(9) pm, 691 reflections, 59 parameters, R1 = 0.069, wR2 = 0.098] and europium oxonitridoborate Eu{sub 5}(BO{sub 2.51(7)}N{sub 0.49(7)}){sub 4} [Pnma, no. 62, Z = 12, a = 2232.2(5), b = 1603.1(3), c = 879.59(18) pm, 2880 reflections, 313 parameters, R1 = 0.027, wR2 = 0.059] were solved from single-crystal X-ray diffraction data. Eu{sub 5}(BO{sub 2.51(7)}N{sub 0.49(7)}){sub 4} adopts a threefold superstructure of the structure of Sr{sub 3}Ln{sub 2}(BO{sub 3}){sub 4} (Ln = Ho, Er). In both structure types, the different cations are situated on common sites with a pronounced preferential occupation but no complete ordering. These conclusions are based on the crystal structure refinement, {sup 151}Eu Moessbauer spectroscopy and MAPLE (Madelung part of lattice energy) calculations. The proposed Eu{sub 5}(BO{sub 3}){sub 4} contains nitrogen and has a formula Eu{sub 5}(BO{sub 2.51(7)}N{sub 0.49(7)}){sub 4} as confirmed by {sup 151}Eu Moessbauer spectroscopy. The optical reflectance spectrum of Eu{sub 5}(BO{sub 2.51(7)}N{sub 0.49(7)}){sub 4} is in accordance with the yellow colour of the compound. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Photocytotoxic lanthanide complexes

    Indian Academy of Sciences (India)

    and Tb(III) complexes in UV-A light of 350 nm.61 The complexes are thus of importance for therapeutic appli- cations in the treatment of accessible tumours like skin melanoma. 3.3 Photoactive non-macrocyclic lanthanide complexes. Lanthanide complexes of non-macrocyclic ligands have recently been studied mainly by ...

  12. Macrocyclic Gd(3+) complexes with pendant crown ethers designed for binding zwitterionic neurotransmitters.

    Science.gov (United States)

    Oukhatar, Fatima; Meudal, Hervé; Landon, Céline; Logothetis, Nikos K; Platas-Iglesias, Carlos; Angelovski, Goran; Tóth, Éva

    2015-07-27

    A series of Gd(3+) complexes exhibiting a relaxometric response to zwitterionic amino acid neurotransmitters was synthesized. The design concept involves ditopic interactions 1) between a positively charged and coordinatively unsaturated Gd(3+) chelate and the carboxylate group of the neurotransmitters and 2) between an azacrown ether appended to the chelate and the amino group of the neurotransmitters. The chelates differ in the nature and length of the linker connecting the cyclen-type macrocycle that binds the Ln(3+) ion and the crown ether. The complexes are monohydrated, but they exhibit high proton relaxivities (up to 7.7 mM(-1)  s(-1) at 60 MHz, 310 K) due to slow molecular tumbling. The formation of ternary complexes with neurotransmitters was monitored by (1) H relaxometric titrations of the Gd(3+) complexes and by luminescence measurements on the Eu(3+) and Tb(3+) analogues at pH 7.4. The remarkable relaxivity decrease (≈80 %) observed on neurotransmitter binding is related to the decrease in the hydration number, as evidenced by luminescence lifetime measurements on the Eu(3+) complexes. These complexes show affinity for amino acid neurotransmitters in the millimolar range, which can be suited to imaging concentrations of synaptically released neurotransmitters. They display good selectivity over non-amino acid neurotransmitters (acetylcholine, serotonin, and noradrenaline) and hydrogenphosphate, but selectivity over hydrogencarbonate was not achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Vnímání barev žákem s mentálním postižením Perception of colours by mentally-handicapped pupils

    Directory of Open Access Journals (Sweden)

    Olga Krejčířová

    2006-02-01

    Full Text Available Předložená stať se pokouší o využití obecných poznatků o barvách v oblasti tělesné kultury a aplikuje je na tělesnou výchovu v podmínkách speciálních škol. Vychází z předpokladu, že vzdělávání žáků s mentálním postižením by mělo probíhat za podmínek, které v nich evokují libé pocity. A k těmto podmínkám patří i barevnost. Jsou prezentovány výsledky šetření preference barev probandy s lehkým a středně těžkým mentálním postižením. Výsledky naznačují, že probandi s lehkým mentálním postižením mají tendenci citlivě vnímat barvy, a to i v abstraktní podobě. Preferují modrou, případně zelenou a červenou barvu a hůře přijímají černou a fialovou. Preference oblíbené barvy je u probandů s těžším mentálním postižením více variabilní než u probandů s lehkým mentálním postižením. The following article attempts to utilize general knowledge of colours in the sphere of physical culture and applies it to physical education in special schools. It is based on the precondition that education of mentally-handicapped pupils should proceed under conditions evoking pleasurable feelings in them. And such conditions also include colours. The article presents the results of an examination of colour preference in probands with slight to moderate mental handicaps. The results show that probands with a slight mental handicap tend to be sensitive in relation to colours, even in their abstract form. They prefer blue, respectively green and red, and they have difficulties with perception of black and violet. The favourite colour preference in probands with a more serious mental handicap is more variable than in probands with a slight mental handicap.

  14. Synthesis, second-harmonic generation (SHG), and photoluminescence (PL) properties of noncentrosymmetric bismuth selenite solid solutions, Bi2-xLnxSeO5 (Ln = La and Eu; x = 0-0.3)

    Science.gov (United States)

    Qi, Hai-Xin; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2018-02-01

    A series of La3+ or Eu3+-doped noncentrosymmetric (NCS) bismuth selenite solid solutions, Bi2-xLnxSeO5 (x = 0.1, 0.2, and 0.3), have been successfully synthesized via standard solid-state reactions under vacuum with Bi2O3, La2O3 (or Eu2O3), and SeO2 as starting materials. Crystal structures and phase purities of the resultant materials were thoroughly characterized by powder X-ray diffraction using the Rietveld method. The results clearly show that the reported materials crystallize in the orthorhombic space group, Abm2 (No. 39), and exhibit pseudo-three-dimensional frameworks consisting of BiO3, BiO5, and SeO3 polyhedra that share edges and corners. Detailed diffraction studies indicate that the cell volume of Bi2-xLnxSeO5 decreases with an increasing amount of Ln3+ on the Bi3+ sites. However, no ordering between Ln3+ and Bi3+ was observed in the Bi2-xLnxSeO5 solid solutions. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that SHG efficiencies of Bi2-xLnxSeO5 solid solutions continuously decrease as more Ln3+ cations are added to the sites of polarizable Bi3+ cations. Photoluminescence (PL) measurements on Bi2-xEuxSeO5 exhibit three specific emission peaks at 592, 613, and 702 nm (5D0 → 7F1, 2, 4) owing to the 4f-4f intrashell transitions of Eu3+ ions.

  15. In vitro and in vivo anti-inflammatory active copper(II-lawsone complexes.

    Directory of Open Access Journals (Sweden)

    Ján Vančo

    Full Text Available We report in vitro and in vivo anti-inflammatory activities of a series of copper(II-lawsone complexes of the general composition [Cu(Law2(LNx(H2O(2-x]·yH2O; where HLaw = 2-hydroxy-1,4-naphthoquinone, x = 1 when LN = pyridine (1 and 2-aminopyridine (3 and x = 2 when LN = imidazole (2, 3-aminopyridine (4, 4-aminopyridine (5, 3-hydroxypyridine (6, and 3,5-dimethylpyrazole (7. The compounds were thoroughly characterized by physical techniques, including single crystal X-ray analysis of complex 2. Some of the complexes showed the ability to suppress significantly the activation of nuclear factor κB (NF-κB both by lipopolysaccharide (LPS and TNF-alpha (complexes 3-7 at 100 nM level in the similar manner as the reference drug prednisone (at 1 μM level. On the other hand, all the complexes 1-7 decreased significantly the levels of the secreted TNF-alpha after the LPS activation of THP-1 cells, thus showing the anti-inflammatory potential via both NF-κB moderation and by other mechanisms, such as influence on TNF-alpha transcription and/or translation and/or secretion. In addition, a strong intracellular pro-oxidative effect of all the complexes has been found at 100 nM dose in vitro. The ability to suppress the inflammatory response, caused by the subcutaneous application of λ-carrageenan, has been determined by in vivo testing in hind-paw edema model on rats. The most active complexes 1-3 (applied in a dose corresponding to 40 μmol Cu/kg, diminished the formation of edema simalarly as the reference drug indomethacine (applied in 10 mg/kg dose. The overall effect of the complexes, dominantly 1-3, shows similarity to anti-inflammatory drug benoxaprofen, known to induce intracellular pro-oxidative effects.

  16. Synthesis, crystal structures, luminescent and magnetic properties of homodinuclear lanthanide complexes with a flexible tripodal carboxylate ligand.

    Science.gov (United States)

    Zhang, Ai-Jiang; Wang, Ya-Wen; Dou, Wei; Dong, Ming; Zhang, Yan-Ling; Tang, Yu; Liu, Wei-Sheng; Peng, Yu

    2011-03-28

    Six new homodinuclear lanthanide(III) complexes with a flexible tripodal carboxylate ligand (H(3)L), of formulae [Ln(2)L(2)(DMF)(4)]·4DMF (Ln = La (1), Nd (2), Eu (3), Gd (4), Tb (5), Dy (6), DMF = N, N-Dimethylformamide) have been synthesized. Among them, 1, 2, 3, 4, 6 were characterized by single-crystal X-ray diffraction, which crystallized in the monoclinic space group P2(1)/n with a = 13.309(2) Å, b = 27.404(4) Å, c = 16.686(3) Å, β = 105.115(2) and V = 5875.2(17) Å(3) for 1, a = 13.3016(5) Å, b = 27.1952(12) Å, c = 16.6339(7) Å, β = 105.030(2) and V = 5811.3(4) Å(3) for 2, a = 13.2797(10) Å, b = 27.072(2) Å, c = 16.6564(13) Å, β = 104.9390(10) and V = 5785.7(8) Å(3) for 3, a = 13.2855(3) Å, b = 27.0074(6) Å, c = 16.6357(3) Å, β = 104.9790(10) and V = 5766.2(2) Å(3) for 4, a = 13.2837(5) Å, b = 26.9105(10) Å, c = 16.6066(6) Å, β = 104.917(2) and V = 5736.3(4) Å(3) for 6. The crystal structures reveal that these complexes are isostructural, and molecules are connected from 0D to 3D supramolecular structures by hydrogen bonds. All of them were characterized by elemental analysis, IR spectroscopy, XRD and TGA. Unusually, non-luminescent Tb(III) complex was obtained. The photophysical property of the Eu(III) complex and the magnetic property of Gd(III) complex are investigated and discussed in detail.

  17. Regionální nástroje na podporu výzkumu, vývoje a inovací v České republice

    Directory of Open Access Journals (Sweden)

    Kostić Miroslav

    2015-09-01

    Full Text Available V souvislosti s probíhajícím procesem přípravy a implementace Národní výzkumné a inovační strategie pro inteligentní specializaci ČR (RIS3 roste význam regionálních samospráv pro realizaci opatření zvyšujících inovační výkonnost kraje a pro posilování aktivní spolupráce veřejné, podnikové a akademické sféry. Příspěvek přibližuje vybrané typy nástrojů na podporu výzkumu, vývoje a inovací, využívané v krajích České republiky (dále ČR. Vychází přitom zejména z údajů z evropského projektu Regional Innovation Monitor Plus. V souboru zde sledovaných regionálních podpůrných programů a aktivit jsou nejčastěji se vyskytujícím typem nástroje inovační vouchery, jejichž hlavním cílem je posílení spolupráce a přenosu znalostí mezi výzkumnou a podnikovou sférou. V některých českých krajích jsou rovněž využívány dotační a úvěrové programy na podporu inovativních podniků. Celkově nízké prostředky plynoucí z regionální úrovně, malá diverzifikace využívaných podpůrných nástrojů ve většině krajů i nedostatečná evaluace ukončených programů představují hlavní výzvy pro regionální inovační politiku v ČR.

  18. Využití dat DPZ pro hodnocení aktuálního stavu a vývoje smrkových porostů v Krkonoších

    OpenAIRE

    Musilová, Romana

    2012-01-01

    Bc. Romana Musilová: Využití dat DPZ pro hodnocení aktuálního stavu a vývoje smrkových porostů v Krkonoších Remote sensing for evaluation of state and development of Spruce stands condition in the Giant Mountains Abstract Monitoring the health status of forest areas using remote sensing methods are still under development. This master thesis focuses on the use of SPOT, Landsat, QuickBird and WorldView-2 images to evaluate condition of spruce stands in Giant Mountains National Park. For these ...

  19. Problémy v sociálním kontaktu s člověkem se zrakovým postižením

    OpenAIRE

    VÍŠKOVÁ, Markéta

    2014-01-01

    Téma: Problémy v sociálním kontaktu s člověkem se zrakovým postižením Autor: Markéta Víšková Abstract The bachelor thesis is focused on the concept of the visual impairment in the context of the phenomenon of otherness, quality of life, social contact and problems that the visual impairment brings in terms of social life. The author assumes that despite all inseparable characteristics and consequences of vision defects, such as problems in orientation and independent movement or deficit of vi...

  20. Approach of Complexity in Nature: Entropic Nonuniqueness

    Directory of Open Access Journals (Sweden)

    Constantino Tsallis

    2016-08-01

    Full Text Available Boltzmann introduced in the 1870s a logarithmic measure for the connection between the thermodynamical entropy and the probabilities of the microscopic configurations of the system. His celebrated entropic functional for classical systems was then extended by Gibbs to the entire phase space of a many-body system and by von Neumann in order to cover quantum systems, as well. Finally, it was used by Shannon within the theory of information. The simplest expression of this functional corresponds to a discrete set of W microscopic possibilities and is given by S B G = − k ∑ i = 1 W p i ln p i (k is a positive universal constant; BG stands for Boltzmann–Gibbs. This relation enables the construction of BGstatistical mechanics, which, together with the Maxwell equations and classical, quantum and relativistic mechanics, constitutes one of the pillars of contemporary physics. The BG theory has provided uncountable important applications in physics, chemistry, computational sciences, economics, biology, networks and others. As argued in the textbooks, its application in physical systems is legitimate whenever the hypothesis of ergodicity is satisfied, i.e., when ensemble and time averages coincide. However, what can we do when ergodicity and similar simple hypotheses are violated, which indeed happens in very many natural, artificial and social complex systems. The possibility of generalizing BG statistical mechanics through a family of non-additive entropies was advanced in 1988, namely S q = k 1 − ∑ i = 1 W p i q q − 1 , which recovers the additive S B G entropy in the q→ 1 limit. The index q is to be determined from mechanical first principles, corresponding to complexity universality classes. Along three decades, this idea intensively evolved world-wide (see the Bibliography in http://tsallis.cat.cbpf.br/biblio.htm and led to a plethora of predictions, verifications and applications in physical systems and elsewhere. As expected

  1. Complex differential geometry

    CERN Document Server

    Zheng, Fangyang

    2002-01-01

    The theory of complex manifolds overlaps with several branches of mathematics, including differential geometry, algebraic geometry, several complex variables, global analysis, topology, algebraic number theory, and mathematical physics. Complex manifolds provide a rich class of geometric objects, for example the (common) zero locus of any generic set of complex polynomials is always a complex manifold. Yet complex manifolds behave differently than generic smooth manifolds; they are more coherent and fragile. The rich yet restrictive character of complex manifolds makes them a special and interesting object of study. This book is a self-contained graduate textbook that discusses the differential geometric aspects of complex manifolds. The first part contains standard materials from general topology, differentiable manifolds, and basic Riemannian geometry. The second part discusses complex manifolds and analytic varieties, sheaves and holomorphic vector bundles, and gives a brief account of the surface classifi...

  2. Synthesis and Structural Investigation of New Bio-Relevant Complexes of Lanthanides with 5-Hydroxyflavone: DNA Binding and Protein Interaction Studies

    Directory of Open Access Journals (Sweden)

    Alexandra-Cristina Munteanu

    2016-12-01

    Full Text Available In the present work, we attempted to develop new metal coordination complexes of the natural flavonoid 5-hydroxyflavone with Sm(III, Eu(III, Gd(III, Tb(III. The resultant hydroxo complexes have been characterized by a variety of spectroscopic techniques, including fluorescence, FT-IR, UV-Vis, EPR and mass spectral studies. The general chemical formula of the complexes is [Ln(C15H9O33(OH2(H2Ox]·nH2O, where Ln is the lanthanide cation and x = 0 for Sm(III, x = 1 for Eu(III, Gd(III, Tb(III and n = 0 for Sm(III, Gd(III, Tb(III, n = 1 for Eu(III, respectively. The proposed structures of the complexes were optimized by DFT calculations. Theoretical calculations and experimental determinations sustain the proposed structures of the hydroxo complexes, with two molecules of 5-hydroxyflavone acting as monoanionic bidentate chelate ligands. The interaction of the complexes with calf thymus DNA has been explored by fluorescence titration and UV-Vis absorption binding studies, and revealed that the synthesized complexes interact with DNA with binding constants (Kb ~ 104. Human serum albumin (HSA and transferrin (Tf binding studies have also been performed by fluorescence titration techniques (fluorescence quenching studies, synchronous fluorescence spectra. The apparent association constants (Ka and thermodynamic parameters have been calculated from the fluorescence quenching experiment at 299 K, 308 K, and 318 K. The quenching curves indicate that the complexes bind to HSA with smaller affinity than the ligand, but to Tf with higher binding affinities than the ligand.

  3. Self-assembly of a helical zinc-europium complex: speciation in aqueous solution and luminescence

    Directory of Open Access Journals (Sweden)

    Emmanuel eDeiters

    2013-09-01

    Full Text Available Two new tridentate(NNO-bidentate(NN compartmental ligands, HL5 and HL6, are synthesized from pyridine and benzimidazole synthons. They react in aqueous solution under physiological conditions with ZnII, LnIII, or a mixture thereof, to yield complexes of different stoichiometries, 1:3, 2:2, 2:3, 1:1:3, the speciation of which is established by UV-visible titrations and ESI mass spectrometry. Photophysical studies of the EuIII-containing solutions in Tris-HCl 0.1 M (pH = 7.4 show that lanthanide luminescence arises from a unique N6O3 coordination site with pseudo D3 symmetry. Relevant parameters such as crystal field splitting, lifetime, radiative lifetime and intrinsic quantum yield perfectly match those reported for dinuclear 4f-4f helicates in which the EuIII ion has the same coordination environment.

  4. Complex and symplectic geometry

    CERN Document Server

    Medori, Costantino; Tomassini, Adriano

    2017-01-01

    This book arises from the INdAM Meeting "Complex and Symplectic Geometry", which was held in Cortona in June 2016. Several leading specialists, including young researchers, in the field of complex and symplectic geometry, present the state of the art of their research on topics such as the cohomology of complex manifolds; analytic techniques in Kähler and non-Kähler geometry; almost-complex and symplectic structures; special structures on complex manifolds; and deformations of complex objects. The work is intended for researchers in these areas.

  5. Determination of the constants of the solubility product of Ln(OH){sub 3} and the effect of the chloride ions on the lanthanum hydrolysis, praseodymium and lutetium in aqueous solutions of ion force 2 Molar; Determinacion de las constantes del producto de solubilidad de Ln(OH){sub 3} y el efecto de los iones cloruro sobre la hidrolisis de lantano, praseodimio y lutecio en soluciones acuosas de fuerza ionica 2 Molar

    Energy Technology Data Exchange (ETDEWEB)

    Lopez G, H.D

    2005-07-01

    The behavior of lanthanum (III), praseodymium (III), and lutetium (III) was studied in 2 M NaClO{sub 4} (aq) and 2 M NaCl (aq) at 303 K and free -CO{sub 2} conditions. Solubility diagrams (p Ln(aq)-pC{sub H}) were obtained by means of a radiochemical method. The pC{sub H} borderlines of saturation and unsaturation zones of the solutions and solubility product constants for Ln(OH){sub 3} were determined from these diagrams. The fitting of the solubility equation to the experimental values of p Ln(aq)-pC{sub H} diagrams allowed the calculation of the first hydrolysis and solubility product constants. Independently, the stability constants for the first species of hydrolysis were determined by means of pH titrations, the data were treated with the program SUPERQUAD and fitted to the mean ligand number equation. The stability constants for the species LnCl{sup 2+} were as well calculated in 2M ionic strength and 303 K from the hydrolysis constant values obtained in both perchlorate and chloride media. The values obtained for La, Pr and Lu were: logK{sub ps}: 21.11 {+-} 0.09, 19.81 {+-} 0.11 and 18.10 {+-} 0.13 in 2M NaClO{sub 4}; logK{sub ps}: 22.22 {+-} 0.09, 21.45 {+-} 0.14 and 18.52 {+-} 0.29 in 2M NaCl; log {beta}{sub 1}: - 8.64 {+-} 0.02, - 8.37 {+-} 0.01 and - 7.95 {+-} 0.11 in 2M NaClO{sub 4}; log {beta}{sub 1}{sup /} : - 9.02 {+-} 0.11, - 8.75 {+-} 0.01 and - 8.12 {+-} 0.03 in 2M NaCl and the values for log {beta}{sub 1,Cl} were - 0.0255, - 0.155 and - 0.758, respectively. (Author)

  6. Adaptive leadership: fighting complexity with complexity

    OpenAIRE

    Smith, Peter

    2014-01-01

    CHDS State/Local Contemporary crises have become increasingly complex and the methods of leading through them have failed to keep pace. If it is assumed that leadership matters—that it has a legitimate effect on the outcome of a crisis, then leaders have a duty to respond to that adaptation with modifications of their own. Using literature sources, the research explores crisis complexity, crisis leadership, and alternative leadership strategies. Specifically, the research evaluates the app...

  7. Photoluminescence studies of a Terbium(III) complex as a fluorescent probe for DNA detection

    Energy Technology Data Exchange (ETDEWEB)

    Khorasani-Motlagh, Mozhgan, E-mail: mkhorasani@chem.usb.ac.ir; Noroozifar, Meissam; Niroomand, Sona; Moodi, Asieh

    2013-11-15

    The photoluminescence properties of a Tb(III) complex of the form [Tb(phen){sub 2}Cl{sub 3}·OH{sub 2}] (phen=1,10-phenanthroline) in different solvents are presented. It shows the characteristic luminescence of the corresponding Ln{sup 3+} ion in the visible region. The emission intensity of this complex in coordinating solvent is higher than non-coordinating one. The suggested mechanism for the energy transfer between the ligand and Tb{sup 3+} ion is the intramolecular energy transfer mechanism. The interactions of the Tb(III) complex with fish salmon DNA are studied by fluorescence spectroscopy, circular dichroism study and viscosity measurements. The results of fluorescence titration reveal that DNA strongly quenches the intrinsic fluorescence of the complex through a static quenching procedure. The binding constant (K{sub b}) of the above metal complex at 25 °C is determined by the fluorescence titration method and it is found to be (8.06±0.01)×10{sup 3} M{sup −1}. The thermodynamic parameters (ΔH{sup 0}>0, ΔS{sup 0}>0 and ΔG{sup 0}<0) indicate that the hydrophobic interactions play a major role in DNA–Tb complex association. The results support the claim that the title complex bonds to FS-DNA by a groove mode. -- Highlights: • Photoluminescence of [Tb(phen){sub 2}Cl{sub 3}·OH{sub 2}] in different solvents are studied. • Tb(III) complex shows good binding affinity to FS DNA with K{sub b}=(8.06±0.01)×10{sup 3} M{sup −1}. • Viscosity of DNA almost unchanged by increasing amount of Tb complex. • CD spectrum of DNA has a little change with increasing amount of Tb complex. • Thermodynamic parameters indicate that the binding reaction is entropically driven.

  8. Spectroscopic, thermal, catalytic and biological studies of Cu(II) azo dye complexes

    Science.gov (United States)

    El-Sonbati, A. Z.; Diab, M. A.; El-Bindary, A. A.; Shoair, A. F.; Hussein, M. A.; El-Boz, R. A.

    2017-08-01

    New complexes of copper(II) with azo compounds of 5-amino-2-(aryl diazenyl)phenol (HLn) are prepared and investigated by elemental analyses, molar conductance, IR, 1H NMR, UV-Visible, mass, ESR spectra, magnetic susceptibility measurements and thermal analyses. The complexes have a square planar structure and general formula [Cu(Ln)(OAc)]H2O. Study the catalytic activities of Cu(II) complexes toward oxidation of benzyl alcohol derivatives to carbonyl compounds were tested using H2O2 as the oxidant. The intrinsic binding constants (Kb) of the ligands (HLn) and Cu(II) complexes (1-4) with CT-DNA are determined. The formed compounds have been tested for biological activity of antioxidants, antibacterial against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and yeast Candida albicans. Antibiotic (Ampicillin) and antifungal against (Colitrimazole) and cytotoxic compounds HL1, HL2, HL3 and complex (1) showed moderate to good activity against S. aureus, E. coli and Candida albicans, and also to be moderate on antioxidants and toxic substances. Molecular docking is used to predict the binding between the ligands with the receptor of breast cancer (2a91).

  9. Oligocyclopentadienyl transition metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    de Azevedo, Cristina G.; Vollhardt, K. Peter C.

    2002-01-18

    Synthesis, characterization, and reactivity studies of oligocyclopentadienyl transition metal complexes, namely those of fulvalene, tercyclopentadienyl, quatercyclopentadienyl, and pentacyclopentadienyl(cyclopentadienyl) are the subject of this account. Thermal-, photo-, and redox chemistries of homo- and heteropolynuclear complexes are described.

  10. Complex carbohydrates (image)

    Science.gov (United States)

    ... foods such as peas, beans, whole grains, and vegetables. Both simple and complex carbohydrates are turned to ... majority of carbohydrates should come from complex carbohydrates (starches) and naturally occurring sugars, rather than processed or ...

  11. Complex systems biology

    OpenAIRE

    Ma'ayan, Avi

    2017-01-01

    Complex systems theory is concerned with identifying and characterizing common design elements that are observed across diverse natural, technological and social complex systems. Systems biology, a more holistic approach to study molecules and cells in biology, has advanced rapidly in the past two decades. However, not much appreciation has been granted to the realization that the human cell is an exemplary complex system. Here, I outline general design principles identified in many complex s...