Magnetic and XMCD studies of Pr1−xSrxMnO3 manganite films

International Nuclear Information System (INIS)

Samoshkina, Yu.E.; Edelman, I.S.; Stepanova, E.A.; Neznakhin, D.S.; Ollefs, K.; Andreev, N.V.; Chichkov, V.I.

2017-01-01

Magnetic properties of the Pr 0.8 Sr 0.2 MnO 3 and Pr 0.6 Sr 0.4 MnO 3 polycrystalline films have been studied using temperature and magnetic field dependences of the static magnetization and X-ray magnetic circular dichroism (XMCD) spectroscopy. For the both compositions, the difference between the temperature dependences of magnetization obtained in the zero fields cooling (ZFC) and field cooling (FC) modes has been revealed. The ZFC curves demonstrate a pronounced maximum at temperature T m . It is shown that the T m value dependence on the magnetic field follows the Almeida-Thouless line typical for the classic spin glass, what allows us to assume the possible spin-glass behavior of the films. Effect of the disorder in a direction of the crystallites easy-axis on the difference between FC and ZFC curves has been discussed also. Magnetic field dependences of the sample magnetization are presented by the hysteresis loops with the shape changing upon temperature variation. This behavior has been attributed to the effect of crystallographic anisotropy and Pr ions. The spectra and magnetic field dependences of XMCD at the Pr L 2 - and Mn K-edges have been studied at 90 K. The magnetic field dependences of the XMCD at the Pr L 2 -edge had shown Van Vleck paramagnetism from Pr 3+ ions. - Highlights: • M (T) magnetization behavior indicates the presence of spin glass behavior in the films. • Shape of the hysteresis loops depends on temperature. • Magnetic field dependences of XMCD at T=90 K reveal Van Vleck paramagnetism from Pr 3+ ions.

Pré-resfriamento em água de lichia 'B3' mantida em armazenamento refrigerado

OpenAIRE

del Aguila,Juan Saavedra; Hofman,Peter; Campbell,Terrence; Marques,José Roberto; Heiffig-del Aguila,Lília Sichmann; Kluge,Ricardo Alfredo

2009-01-01

Este experimento visou a estudar o efeito de diferentes temperaturas e tempos de pré-resfriamento em água sobre a qualidade de lichias 'B3', após a frigoconservação. Os tratamentos foram: T1 = controle (sem pré-resfriamento); T2 = imersão por cinco minutos em água a 2,5°C; T3 = imersão por 10 minutos em água a 2,5°C; T4 = imersão por 20 minutos em água a 2,5°C; T5 = imersão por sete minutos em água a 6°C; T6 = imersão por 20 minutos em água a 8°C e T7 = imersão por 10 minu...

Energy transfer between Pr3+ and Mn2+ in K2YZr(PO4)3: Pr, Mn phosphor

International Nuclear Information System (INIS)

Liang Wei; Wang Yuhua

2011-01-01

Research highlights: → Pr 3+ , Mn 2+ co-doped K 2 YZr(PO 4 ) 3 phosphor is a novel type of practical visible quantum cutting phosphor in promising application. → The optimal quantum efficiency (QE) of this co-doped system K 2 YZr(PO 4 ) 3 : Pr 3+ , Mn 2+ reached to 126.3%. → The Mn 2+6 A 1g → 4 E g - 4 A 1g transition was found to coincide well with the 1 S 0 → 1 I 6 transition of Pr 3+ . → The energy transfer from Pr 3+ to Mn 2+ was also observed, converting the first photon from the PCE of Pr 3+ into the red emission of Mn 2+ , and the QC process occurred in this Pr 3+ , Mn 2+ co-doped K 2 YZr(PO 4 ) 3 phosphor. - Abstract: Pr 3+ , Mn 2+ co-doped K 2 YZr(PO 4 ) 3 samples were prepared by solid-state reaction method and their photoluminescence (PL) properties were investigated in ultra-violet (UV) and vacuum ultra-violet (VUV) region. The results indicated that in Pr 3+ singly doped K 2 YZr(PO 4 ) 3 sample, the first-step transition ( 1 S 0 → 1 I 6 , 3 P J around 405 nm) of Pr 3+ is near the ultraviolet (UV) range, not useful for practical application. When Mn 2+ was doped as a co-activator ion, the energy of 1 S 0 → 1 I 6 , 3 P J transition can be transferred synchronously from Pr 3+ to Mn 2+ and then emit a visible photon. The optimal quantum efficiency (QE) of this co-doped system K 2 YZr(PO 4 ) 3 : Pr 3+ , Mn 2+ reached to 126.3%, suggesting a novel type of practical visible quantum cutting phosphor in promising application.

Magnetic properties of Pr ions in perovskite-type oxides

International Nuclear Information System (INIS)

Sekizawa, K.; Kitagawa, M.; Takano, Y.

1998-01-01

Magnetic properties of Pr ions with the controlled valence on the A and B sites of perovskite-type oxides (ABO 3 ) were investigated for two systems. PrSc 1-x Mg x O 3 and BaPr 1-x Bi x O 3 . From the magnetic susceptibility χ versus temperature T curves of PrSc 1-x Mg x O 3 , the χ-T curve for molar Pr 3+ ions on the A site and that of Pr 4+ ions were obtained. The 1/χ-T curves for both ions exhibit the crystalline electric field (CEF) effect and the effective magneticmoment μ eff above 100 K is 3.41 μ B for Pr 3- and 2.58 μ B for Pr 4+ , respectively. The χ-T curve of PrSc 0.8 Mg 0.2 O 3 is similar to that of PrBa 2 Cu 3 O y . In the BaPr 1-x Bi x O 3 system, only one intermediate phase BaPr 0.5 Bi 0.5 O 3 exists, in which Pr and Bi take an ordered arrangement on the B site. The magnetic susceptibility χ for Pr 4+ and that of Pr 3+ in the ordered arrangement with Bi 5- on the B site are much smaller than those for the A site, reflecting the strong CEF effect on the B site. Experimental χ-T curves can be well reproducedby the numerical calculation for Pr 3+ or Pr 4+ ions in the molecular field and the CEF with proper respective parameters. (orig.)

Study into non-quasibinary sections of Pr2S3-Bi2S3-Pr2O3 triple system (Bi2S3)0. 45(Pr2O3)0. 55 - (Bi2S3)0. 45(Pr2S3)0. 55 and (Bi2S3)0. 75 (Pr2S3)0. 25 - (Bi2S3)0. 75(Pr2O3)0. 25

OpenAIRE

НЕЙМАТОВА А.В.; МАМЕДОВ Ф.М.; БАХТИЯРЛЫ И.Б.

2016-01-01

Методами дифференциальнo-термическoго (ДТ), рентгенофазового (РФ), микроструктурного (МС) методов анализа исследованы неквазибинарные разрезы (Bi2S3)0.45(Pr2O3)0.55 (Bi2S3)0.45(Pr2S3)0.55 и (Bi2S3)0.75 (Pr2S3)0.25 (Bi2S3)0.75(Pr2O3)0.25 тройной системы Pr2S3-Bi2S3-Pr2O3 построена диаграмма состояния, определены координанты нони моновариантныхравновесий....

Pr4N2S3 and Pr4N2Se3: two non-isostructural praseodymium(iii) nitride chalcogenides

International Nuclear Information System (INIS)

Lissner, Falk; Schleid, Thomas

2005-01-01

The non-isostructural nitride chalcogenides of praseodymium, Pr 4 N 2 S 3 and Pr 4 N 2 Se 3 , are formed by the reaction of the praseodymium metal with sodium azide (NaN 3 ), praseodymium trihalide (PrX 3 ; X = Cl, Br, I) and the respective chalcogen (sulfur or selenium) at 900 C in evacuated silica ampoules after seven days. Both crystallize monoclinically in space group C2/c (Pr 4 N 2 S 3 : a = 1788.57(9), b = 986.04(5), c = 1266.49(6) pm, β = 134.546(7) , Z = 8; Pr 4 N 2 Se 3 : a = 1311.76(7), b = 1017.03(5), c = 650.42(3) pm, β = 90.114(6) , Z = 4). The crystal structures of both compounds show a layered construction, dominated by N 3- -centred (Pr 3+ ) 4 tetrahedra which share a common edge first. Continuing linkage of the so resulting bitetrahedral [N 2 Pr 6 ] 12+ units via the non-connected vertices to layers according to [stack ∞ 2 ]{[N(Pr) 2/2 e (Pr') 2/2 v ] 3+ } forms different kinds of tetrahedral nets which can be described as layers consisting of ''four- and eight-rings'' for Pr 4 N 2 S 3 and as layers of ''six-rings'' for Pr 4 N 2 Se 3 . Whereas the crystal structure of Pr 4 N 2 S 3 exhibits four different Pr 3+ cations with coordination numbers of six (2 x) and seven (2 x) against N 3- and S 2- , the number of cations in the nitride selenide (Pr 4 N 2 Se 3 ) is reduced to half (Pr1 and Pr2) also having six- and sevenfold anionic coordination spheres. Further motifs for the connection of [NM 4 ] 9+ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare-earth elements with ratios of N: M = 1: 2 are presented and discussed. (Abstract Copyright [2005], Wiley Periodicals, Inc.) [de

Thermal reorientation of hydrogenic Pr3+ centers

International Nuclear Information System (INIS)

Jones, G. D.

1996-01-01

Sets of five multi-hydrogenic centers of both CaF 2 :Pr 3+ and SrF 2 :Pr 3 + show bleaching under selective polarized-light irradiation. Two forms of bleaching behaviour are observed. In reversible polarized bleaching, irradiation creates re-oriented equivalent centers, which can be restored to the original orientation by switching the laser polarization by 90 deg. Indefinite sequences of bleaching and recovery can be established. In photoproduct bleaching, inequivalent centers are produced, which can be reverted by subsequently selectively exciting their absorption lines. Thermal recovery of the bleached centers on warming the crystals occurs abruptly over a 5 K range around 100 K and is noteworthy in occurring at essentially identical temperatures for H - , D - and T - centers. The simplest model for this thermal recovery is thermal activation of the mobile hydrogenic ions over a double well potential barrier. An alternative model proposed by Universitaet Regensburg requires the involvement of high frequency excitations in scattering processes for surmounting the barrier

X-ray-scattering study of copper magnetism in nonsuperconducting PrBa2Cu3O6.92

DEFF Research Database (Denmark)

Hill, J.P.; McMorrow, D.F.; Boothroyd, A.T.

2000-01-01

X-ray magnetic scattering from ordered Cu spins has been observed in a high-T-c compound. The measurements were made on the anomalous cuprate PrBa2Cu3O6.92 with x-ray photon energies tuned in the vicinity of the Cu K edge. The high wave-vector resolution enabled us to observe an incommensurate...... double-Q Cu spin structure below T-Pr = 19 K that forms as a result of coupling between the magnetically ordered Cu and Pr sublattices. Above T-Pr, the Cu ordering is commensurate, ruling out static spin-charge stripe order as an explanation for the absence of superconductivity in this material....

Aspects of Pr3+ luminescence in solids

International Nuclear Information System (INIS)

Srivastava, A.M.

2016-01-01

A brief perspective on the influence of “host lattice-Pr 3+ ” interactions on the optical properties of the Pr 3+ ion in solids is presented. How the energy position of the Pr 3+ 4f 1 5d 1 configuration relative to the 1 S 0 , 3 P J and host lattice conduction band levels influences the Pr 3+ optical properties is highlighted by considering solids in which the 4f 1 5d 1 configuration (1) is energetically above the 1 S 0 level, (2) is energetically below the 1 S 0 level, (3) is energetically close to the 1 S 0 level, and (4) overlaps with the host lattice conduction band. - Highlights: • Spectroscopic properties of Pr 3+ in solids is examined. • The influence of Pr 3+ 4f 1 5d 1 energy position relative to the 4f 2 levels is discussed. • The effect of interaction between Pr 3+ 4f 1 5d 1 and host conduction level is illustrated. • The paper identifies potential commercial applications.

Determination of the differences in oxidation potentials for the Pr3+/Pr2+ and Ce3+/Ce2+ pairs in halide melts

International Nuclear Information System (INIS)

Mikheev, N.B.; Auerman, L.N.; Rumer, I.A.; D'yachkova, R.A.

1983-01-01

Cocrystallization has been used with the (PrOCl)/sub s. ph/ - (PrCl 2 , PrCl 3 , SrCl 2 ) melt system to examine the dependence of the cerium(III) cocrystallization coefficient on the X/sub Pr 2+ /X/sub Pr 3+ / ratio in the melt. Measurement has been made in this way of the difference in oxidation potentials for the pairs Pr 3+ /Pr 2+ and Ce 3+ /Ce 2+ : ΔE/sub Pr 3+ /Pr 2+0 -E/sub Ce 3+ /Ce 2+ / 0 , which is 0.08 +/- 0.04 V for chloride

Magnetic ordering in single crystals of PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta

CERN Document Server

Uma, S; Gmelin, E; Rangarajan, G; Skanthakumar, S; Lynn, J W; Walter, R; Lorenz, T; Büchner, B; Walker, E; Erb, A

1998-01-01

Heat capacity measurements on pure but twinned single crystals of PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta reveal a sharp peak at T sub N sup P sup sub T =16.6 K, which according to thermal expansion, neutron diffraction, and magnetic susceptibility measurements originates from an antiferromagnetic ordering of the Pr-ion moments. A modest coupling to the Cu(2) spin system is observed. Below T sub N sup P sup sub T a first-order transition in the magnetic structure of the Pr spin system (at 13.4 K in warming; approx. 11 K in cooling) is found. Field-dependent heat capacity data show anisotropic temperature dependences of the c sub p -peaks and recover a Schottky-like anomaly due to the crystal-field-split ground state of the Pr sup 3 sup +. (author). Letter-to-the-editor

Thermal expansion and magnetostriction of clathrate compound Pr3Pd20Ge6

Science.gov (United States)

Matsumoto, K.; Sekiguchi, Y.; Iwakami, O.; Ono, T.; Abe, S.; Ano, G.; Akatsu, M.; Mitsumoto, K.; Nemoto, Y.; Goto, T.; Takeda, N.; Kitazawa, H.

2018-03-01

In Pr3Pd20Ge6, the Pr ions are located at two different crystallographic sites, 4a and 8c site. Antiferro-quadrupole ordering (AFQ) of the 8c site occurs at 250 mK. Ac susceptibility measurement indicated that antiferromagnetic ordering (AFM) of the 4a site and Hyperfine-enhanced Pr nuclear magnetic ordering of the 8c site occur at 77 and 9 mK, respectively. To clarify the magnetic and quadrupole properties of Pr3Pd20Ge6, thermal expansion and magnetostriction measurements on single crystal sample were carried out along the [001] direction up to 8 T down to 500 μK using a capacitive dilatometer. In zero field, relative length change ΔL/L in [001] direction had a dip at AFQ and abrupt decrease at AFM ordering. From thermal expansion and isothermal magnetostriction measurements, magnetic phase diagram of Pr3Pd20Ge6 along [001] direction was obtained.

Podpora týmové práce ve Visual Studiu 2005

OpenAIRE

Bureš, Petr

2007-01-01

Cílem práce je seznámit čtenáře se způsoby, jimiž Visual Studio 2005 Team System (VSTS) podporuje týmovou práci při vývoji software. Práce se neomezuje jen na popis faktů, ale snaží se kromě vysvětlení souvislosti mezi jednotlivými prvky tyto prvky prostřednictvím demonstračního projektu použít a zhodnotit. Nejprve se nastiňuje problematika podpory vývojových týmů v kontextu rostoucí náročnosti projektů. Další část se zabývá stručným popisem nových rysů řešení VSTS. Třetí část tyto rysy na de...

Evolution of structural, magnetic and transport behavior by Pr doping in SrRuO3

Science.gov (United States)

Gupta, Renu; Pramanik, A. K.

2018-05-01

Here we report the evolution of structural, magnetic and transport behavior in perovskite based ruthenates Sr1-xPrxRuO3 (x=0.0 and 0.1). The substitution of Pr on Sr site retains orthorhombic structure while we find the slight change in structural parameters. The SrRuO3 has itinerant ferromagnet (FM) type nature of ordering temperature ˜160 K and below the transition temperature showing large bifurcation between ZFC and FC magnetization. By Pr doping, the magnetic moment decreases with decreasing bifurcation of ZFC and FC. The ZFC data show three distinct peaks (three transition temperature; TM1,TM2 and TM3). The magnetization study of both the samples, at high temperature fitted with modified CWL showing the decreasing value of ordering temperature by Pr doping matches close to TM2. The low-temperature isothermal magnetization M (H) data show that the high field saturation moment has decreased by Pr doping. The Arrott plot gives spontaneous magnetization (Ms) which is also decreased by Pr substitution. Evolution of Rhodes-Wohlfarth ratio value increases, which suggests that FM in this system evolves toward the more itinerant type by Pr doping. The electrical resistivity ρ(T) of both the samples show metallic behavior, in the all temperature range and ρ(T) increases by Pr doping while around below 45 K, the resistivity decreases by Pr doping and this crossing temperature also matches with ZFC data.

Magnetic properties in the vortex state of Pr1-xNdxPt4Ge12 and PrPt3.88Fe0.12Ge12 superconductors

Science.gov (United States)

Chandra, L. S. Sharath; Chattopadhyay, M. K.

2018-03-01

We report the temperature and magnetic field dependence of magnetization of Pr1-xNdxPt4Ge12 (x = 0, 0.05 and 0.1) and PrPt3.88Fe0.12Ge12 below 10 K and up to 2 T magnetic field. When compared to the parent PrPt4Ge12, while the critical current density and flux pinning properties are enhanced in the Pr1-xNdxPt4Ge12 samples, they are considerably diminished in the PrPt3.88Fe0.12Ge12 sample. We argue that the observed changes are related to the way the substituting atoms at different crystallographic sites influence the superconductivity in these Germanide skutterudites.

Mechanoluminescence and photoluminescence of Pr3+ activated KMgF3 phosphor

International Nuclear Information System (INIS)

Dhoble, S.J.; Kher, R.S.; Furetta, C.

2003-01-01

A Czochralski method for the preparation of crystalline KMgF 3 : Pr phosphors are reported. Photoluminescence (PL) and mechanoluminescence (ML) characteristics are studied. Photoluminescence of Pr 3+ activated KMgF 3 shows the strong emission of Pr 3+ ions were observed at 498 and 650 nm by excitation of 213 mn. ML of KMgF 3 : Pr 3+ shows two peaks, which have been observed in ML intensity versus time curve. The ML peak shows the recombination of electrons with free radical (anion radical produced by γ-irradiation) released from two type traps during the mechanical pressure applied on KMgF 3 : Pr 3+ phosphor. It has a supra linear ML response with γ-ray exposure and a negligible fading. These properties of phosphor should be suitable in dosimetry of ionization relation using ML technique. Therefore the KMgF 3 : Pr 3+ phosphor proposed for ML dosimetry of ionization radiations. (Author)

Luminescence dependence of Pr3+ activated SiO2 nanophosphor on Pr3+ concentration, temperature, and ZnO incorporation

CSIR Research Space (South Africa)

Mhlongo, GH

2011-08-01

Full Text Available Green-emitting ZnO nanoparticles were successfully embedded in Pr3+-doped SiO2 by a sol–gel method resulting in a red-emitting ZnO·SiO2:Pr3+ nanocomposite phosphor. The particle morphology and luminescent properties of SiO2:Pr3+ phosphor powders...

Two-stage multipolar ordering in Pr T2Al20 Kondo materials

Science.gov (United States)

Freyer, Frederic; Attig, Jan; Lee, SungBin; Paramekanti, Arun; Trebst, Simon; Kim, Yong Baek

2018-03-01

Among heavy fermion materials, there is a set of rare-earth intermetallics with non-Kramers Pr3 +4 f2 moments which exhibit a rich phase diagram with intertwined quadrupolar orders, superconductivity, and non-Fermi liquid behavior. However, more subtle broken symmetries such as multipolar orders in these Kondo materials remain poorly studied. Here, we argue that multi-spin interactions between local moments beyond the conventional two-spin exchange must play an important role in Kondo materials near the ordered to heavy Fermi liquid transition. We show that this drives a plethora of phases with coexisting multipolar orders and multiple thermal phase transitions, providing a natural framework for interpreting experiments on the Pr(T) 2Al20 class of compounds.

Influence of the valence states of atoms on conducting properties of PrBa2Cu3O6+x

International Nuclear Information System (INIS)

Romanenko, A.I.; Zakharchuk, N.F.; Naumov, N.G.; Fedorov, V.E.; Paek, U.H.

1997-01-01

Pr 3+ valent state only was discovered in PrBa 2 Cu 3 O 6+x within the oxygen content range 0.4 ≤ x ≤ 0.6. Out of this range, Pr 4+ state appears also. All the samples obtained showed insulating behavior of resistivity r(T). In PrBa 2 Cu 3 O 6+x (0.4 ≤ x ≤ 0.6), the resistivity is Mott variable-range hopping conduction type and is connected with oxygen disorder only. Out of this range, the localization is much stronger; this increase is due to Pr 4+ /Pr 3+ position disorder. Also, the localization decreases after annealing at room temperature is the result of ordering. Thus, the absence of metallic (and therefore superconducting) state in PrBa 2 Cu 3 O 6+x is due to the presence of both Pr 4+ and Pr 4+ /Pr 3+ disorder

Magnetic and XMCD studies of Pr{sub 1−x}Sr{sub x}MnO{sub 3} manganite films

Energy Technology Data Exchange (ETDEWEB)

Samoshkina, Yu.E., E-mail: uliag@iph.krasn.ru [Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk 660036 (Russian Federation); Edelman, I.S. [Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk 660036 (Russian Federation); Stepanova, E.A.; Neznakhin, D.S. [Ural Federal University, Yekaterinburg 620000 (Russian Federation); Ollefs, K. [European Synchrotron Radiation Facility (ESRF), BP 220, 38043 Grenoble Cedex 9 (France); Andreev, N.V.; Chichkov, V.I. [National University of Science and Technology “MISiS”, Moscow 119049 (Russian Federation)

2017-04-15

Magnetic properties of the Pr{sub 0.8}Sr{sub 0.2}MnO{sub 3} and Pr{sub 0.6}Sr{sub 0.4}MnO{sub 3} polycrystalline films have been studied using temperature and magnetic field dependences of the static magnetization and X-ray magnetic circular dichroism (XMCD) spectroscopy. For the both compositions, the difference between the temperature dependences of magnetization obtained in the zero fields cooling (ZFC) and field cooling (FC) modes has been revealed. The ZFC curves demonstrate a pronounced maximum at temperature T{sub m}. It is shown that the T{sub m} value dependence on the magnetic field follows the Almeida-Thouless line typical for the classic spin glass, what allows us to assume the possible spin-glass behavior of the films. Effect of the disorder in a direction of the crystallites easy-axis on the difference between FC and ZFC curves has been discussed also. Magnetic field dependences of the sample magnetization are presented by the hysteresis loops with the shape changing upon temperature variation. This behavior has been attributed to the effect of crystallographic anisotropy and Pr ions. The spectra and magnetic field dependences of XMCD at the Pr L{sub 2}- and Mn K-edges have been studied at 90 K. The magnetic field dependences of the XMCD at the Pr L{sub 2}-edge had shown Van Vleck paramagnetism from Pr{sup 3+} ions. - Highlights: • M (T) magnetization behavior indicates the presence of spin glass behavior in the films. • Shape of the hysteresis loops depends on temperature. • Magnetic field dependences of XMCD at T=90 K reveal Van Vleck paramagnetism from Pr{sup 3+} ions.

Superstructure formation in PrNi{sub 2}Al{sub 3} and ErPd{sub 2}Al{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Eustermann, Fabian; Hoffmann, Rolf-Dieter [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Oldenburg Univ. (Germany). Inst. fuer Chemie

2017-09-01

The intermetallic phase ErPd{sub 2}Al{sub 3} was obtained by arc-melting of the elements and subsequent annealing for crystal growth. The sample was studied by X-ray diffraction on powders and single crystals. The structure of ErPd{sub 2}Al{sub 3} was refined from X-ray diffraction data and revealed a superstructure of PrNi{sub 2}Al{sub 3} - a CaCu{sub 5} derivative (P6/m, a=1414.3(1), c=418.87(3) pm wR=0.0820, 1060 F{sup 2} values, 48 variables). The same superstructure was subsequently found for PrNi{sub 2}Al{sub 3} (P6/m, a=1407.87(4), c=406.19(2) pm, wR=0.0499, 904 F{sup 2} values, 47 variables). In the crystal structure, the aluminium and transition metal atoms form a polyanionic network according to [T{sub 2}Al{sub 3}]{sup δ-}, while rare earth atoms fill cavities within the networks. They are coordinated by six transition metal and twelve aluminum atoms. In contrast to the PrNi{sub 2}Al{sub 3} type structure reported so far, two crystallographic independent rare-earth sites are found of which one (1b) is shifted by 1/2 z, causing a distortion in the structure along with a recoloring of the T and Al atoms in the network.

Cu4Pr6(MoO4)11-Pr2(MoO4)3 system

International Nuclear Information System (INIS)

Arzumanyan, G.A.

1982-01-01

Existence boundaries and Dalton compositions (CuPr(MoO 4 ) 2 , CuPr 3 (MoO 4 ) 5 ) of solid solutions that in the mojority are of shcheelite dsitored structure have been determined in the Cu 4 Pr 6 (MoO 4 ) 11 -Pr 2 (MoO 4 ) 3 system. It has been revealed that regions of homogeneity near the CuPr(MoO 4 ) 2 composition have a horseshoeshaped profile

Energy transfer in LaF3: R3+, Pr3+ (where R = Nd, Dy)

International Nuclear Information System (INIS)

Reddy, B.R.; Venkateswarlu, P.

1982-01-01

Fluorescence is observed for 1 D 2 levels of Pr 3+ on exciting the higher lying level 3 P 0 in doubly doped systems LaF 3 : R 3+ , Pr 3+ (R = Nd or Dy) but not in LaF 3 :Pr 3+ . From the recorded excitation spectra, and the measured decay times, it has been found that the drain mechanism of population to 1 D 2 levels is caused in doubly doped systems by ion-pair relaxation between Pr 3+ ( 3 P 0 -- 1 D 2 ) and Nd 3+ (Z-X) or Dy 3+ (Z-Y) ions

Photon cascade luminescence from Pr3+ ions in LiPrP4O12 polyphosphate

International Nuclear Information System (INIS)

Shalapska, T; Stryganyuk, G; Romanyshyn, Yu; Demchenko, P; Voloshinovskii, A; Trots, D; Gektin, A; Dorenbos, P

2010-01-01

The spectral-kinetic properties of luminescence from LiY 1-x Pr x P 4 O 12 (x = 1, 0.1) phosphors are studied in the 10-300 K temperature range upon excitation within the UV-VUV spectral range. The luminescence observed for LiPrP 4 O 12 at low temperatures is attributed to both intra-configurational 4f 2 → 4f 2 and inter-configurational 4f5d → 4f 2 radiative transitions of Pr 3+ . The temperature dependence of emission and the decay kinetics of Pr 3+ luminescence from LiY 1-x Pr x P 4 O 12 (x = 1, 0.1) phosphors are explained by temperature stimulated transitions from the 1 S 0 to the Pr 3+ 4f5d state. At low temperatures, the energy potential barrier between the 1 S 0 and 4f5d states is 0.014 eV for LiPrP 4 O 12 . The spectral overlap of the 1 S 0 and 4f5d states of Pr 3+ in LiY 0.9 Pr 0.1 P 4 O 12 determines the luminescence properties in the entire temperature range studied.

Paramagnetic fluctuations in Pr0.65Ca0.35MnO3 around the charge-ordering temperature

International Nuclear Information System (INIS)

Daoud-Aladine, A; Roessli, B; Gvasaliya, S N; Perca, C; Pinsard-Gaudart, L; Rodriguez-Carvajal, J; Revcolevschi, A

2006-01-01

We have studied the ferromagnetic and antiferromagnetic fluctuations in the charge-ordered Pr 0.65 Ca 0.35 MnO 3 antiferromagnet by triple-axis neutron spectrometry. Whereas ferromagnetic fluctuations are observed above and below the charge-ordering transition (T CO ), the antiferromagnetic fluctuations develop only below T CO . The dynamical exponent z of both ferromagnetic and antiferromagnetic fluctuations are determined. The ferromagnetic fluctuations are not completely suppressed below T CO and their correlation lengths are short-ranged at all temperatures. The results are discussed with respect to the Zener polaron model recently introduced to describe the charge-ordered state of Pr 0.6 Ca 0.40 MnO 3

Phase relations in the SiC-Al2O3-Pr2O3 system

International Nuclear Information System (INIS)

Pan, W.; Wu, L.; Jiang, Y.; Huang, Z.

2016-01-01

Phase relations in the Si-Al-Pr-O-C system, including the SiC-Al 2 O 3 -Pr 2 O 3 , the Al 2 O 3 -Pr 2 O 3 -SiO 2 and the SiC-Al 2 O 3 -Pr 2 O 3 -SiO 2 subsystems, were determined by means of XRD phase analysis of solid-state-reacted samples fabricated by using SiC, Al 2 O 3 , Pr 2 O 3 and SiO 2 powders as the starting materials. Subsolidus phase diagrams of the systems were presented. Two Pr-aluminates, namely PrAlO 3 (PrAP) and PrAl 11 O 18 (β(Pr) β-Al 2 O 3 type) were formed in the SiC-Al 2 O 3 -Pr 2 O 3 system. SiC was compatible with both of them. Pr-silicates of Pr 2 SiO 5 , Pr 2 Si 2 O 7 and Pr 9.33 Si 6 O 26 (H(Pr) apatite type) were formed owing to presence of SiO 2 impurity in the SiC powder. The presence of the SiO 2 extended the ternary system of SiC-Al 2 O 3 -Pr 2 O 3 into a quaternary system of SiC-Al 2 O 3 -SiO 2 -Pr 2 O 3 (Si-Al-Pr-O-C). SiC was compatible with Al 2 O 3 , Pr 2 O 3 and the Pr-silicates. The effect of SiO 2 on the phase relations and liquid phase sintering of SiC ceramics was discussed.

Detección de anticuerpos contra los antígenos de diferenciación tumoral proteinasa 3 (PR3 y mieloperoxidasa (MPO en la leucemia promielocítica Detection of antibodies to antigens of proteinase 3 (PR3 tumor differentiations and myeloperoxidase (MPO in cases of promyelocytic leukemia

Directory of Open Access Journals (Sweden)

Ada A. Arce Hernández

2010-08-01

Full Text Available La leucemia promielocítica (LPM subtipo M3 representa del 5-15 % en la clasificación FAB de las leucemias mieloides agudas (LMA. Está asociada con características genéticas únicas que incluyen la translocación recíproca t(15;17(q22;q12. El mecanismo por el que ocurre la t(15;17 no se conoce. Las leucemias de estirpe mieloide expresan diversos antígenos de diferenciación tumoral como son la proteinasa 3 (PR 3 y la mieloperoxidasa (MPO que se encuentran sobreexpresados en el promielocito. Se plantea que participan en la maduración y en la regulación de la división celular. Existe poca información acerca de la respuesta inmune de pacientes con LPM dirigida contra las células tumorales. En nuestro trabajo se detectó la presencia de anticuerpos contra los antígenos de diferenciación tumoral PR3 y MPO en diferentes fases del tratamiento de la enfermedad, mediante inmunofluorescencia indirecta. Los anticuerpos anti PR3 y anti MPO se detectaron en aquellos pacientes sin tratar y en fase de inducción, no así en la consolidación y mantenimiento, de ahí su posible utilidad como marcadores de diferenciación celular.ABSTRACT Promyelocytic leukemia (PML subtype M3 represents the 5-15 % in the FAB classification of acute myeloid leukemias (AML. It is associated with the unique genetic features including the reciprocal t-translocation (15;17 (q22;q12. The mechanism of t is unknown. The myeloid leukemias express different tumoral differentiation antigens such as the proteinase 3 (PR 3 and myeloperoxidase (MPO which are over-expressed in promyelocyte. It is involved in maturation and regulation of cell division. There is scarce information on the immune response of patients with PLM against tumor cells. In our paper we detected presence of antibodies to RP3 and MPO tumor differentiation antigens in different phases of disease treatment by indirect immunofluorescence. Anti-MPO and anti-PR3 antibodies were detected in those patients without

Effects of ethiodol on T3 kinetics in endemic goiter area

International Nuclear Information System (INIS)

Watanabe, Tomas; Degrossi, O.J.; Zaninovich, A.A.; Altschuler, Noe; Degrossi, E.B.

1986-01-01

T3 kinetics were carried out in 32 children (11-15 years old) of a mild endemic goiter area. The incidence of goiter of the whole school population was 19% (Ia or Ib degree of the WHO). The mean urinary iodine was 84 μ g/d+-3. Six months before this investigation, 10 of the children received 2 ml of ethiodol by mouth and the other 22 (control group-CG) a placebo. The kinetics studies were carried out using less than 0,5 μ Ci of I-125 per Kg b.w. and the single injection method, non compartimental analysis. The CG shows, distribution volumen (V) 20.1+-0.6; serum T3 (sT3) 1.55 ng/ml+-0.03; plasma T3 T1/2 21.6+-0.6 and production rate (PR) 27.4μ g/d+-1.2. The treated group (TG): V, 17.3+-0.6; sT3 1.48 ng/ml+-0.09; T1/2 17.6+-0.6 and PR 25.9μ g/d+-1.4. The TG, after 6 months of ethiodol administration, showed a decrease of the distribution volume and a slight reduction in serum T3 values. As a consequence a significant diminution on the T3 extrathyroidal pool and an increase on the T3 plasma clearance (0.68 l/h+-0.01 in CG versus 0.73+-0.3 in TG) were observed. The production ratewas similar in both groups. These results indicate that the administration of ethiodol to children of a not severe endemic goiter area, produces moderate changes in the different parameters of T3 peripheral metabolism, which compensate each other and lead to similar final values on T3-PR, that were previously normal in these cases. This mechanism reflects the role of thyroid homeostasis in maintaining euthyroidism in these children of an endemic goiter area with decreased iodine supply. (Author) [es

Conventional and inverse magnetocaloric effect in Pr2CuSi3 and Gd2CuSi3 compounds

International Nuclear Information System (INIS)

Wang, Fang; Yuan, Feng-ying; Wang, Jin-zhi; Feng, Tang-fu; Hu, Guo-qi

2014-01-01

Highlights: • Two phase transitions in a narrow temperature range were observed and studied. • Both typical and inverse magnetocaloric effect were observed and discussed. • The inverse magnetocaloric effect was attributed to the spin-glass behavior. - Abstract: Magnetic properties and magnetocaloric effect (MCE) in Pr 2 CuSi 3 and Gd 2 CuSi 3 compounds were investigated systematically. Both Pr 2 CuSi 3 and Gd 2 CuSi 3 compounds experienced two phase transitions in a relatively narrow temperature range: first a paramagnet (PM)–ferromagnet (FM) second-order phase transition at 12 and 26 K and then a FM–spin glass (SG) transition at 6 K and 7.5 K, respectively. The magnetic entropy change (ΔS M ) was calculated based on Maxwell relation using the collected magnetization data. The maximum of ΔS M for Pr 2 CuSi 3 and Gd 2 CuSi 3 compounds was 7.6 and 5 J kg −1 K −1 , respectively, at the applied filed change of 0–5 T. The shape of the temperature dependence of ΔS M (ΔS M –T) curve was obviously different from that of the conventional magnetic materials undergoing only one typical phase transition. In the left half part of ΔS M –T curve, ΔS M is not very sensitive to the applied field and they tend to intersect with the decrease of temperature. Both typical conventional and inverse MCE behavior were observed in Gd 2 CuSi 3 , which would be originated from the two transition features at the low temperatures

Pathogenesis of PR3-ANCA associated vasculitis

NARCIS (Netherlands)

Kallenberg, C. G. M.

2008-01-01

Wegener's Granulomatosis (WG) is closely associated with antineutrophil cytoplasmic autoantibodies (ANCA), particularly those directed to proteinase 3 (PR3). ANCA directed to myeloperoxidase (MPO) are associated with microscopic polyangiitis (MPA) and the Churg Strauss syndrome. PR3-ANCA associated

Downconversion in Pr3+–Yb3+ co-doped ZBLA fluoride glasses

International Nuclear Information System (INIS)

Maalej, O.; Boulard, B.; Dieudonné, B.; Ferrari, M.; Dammak, M.; Dammak, M.

2015-01-01

Fluorozirconate ZBLA glasses with molar composition 57ZrF 4 –34BaF 2 –5LaF 3 –4AlF 3 –0.5PrF 3 –xYbF 3 (from x=0 to 10) were synthesized to evaluate the rate of the conversion of visible photons into infrared photons. The emission spectra in the near infrared (NIR) at 950–1100 nm and the luminescence decays in the visible and NIR indicate an energy transfer from Pr 3+ to Yb 3+ upon blue excitation of Pr 3+ at 440 nm. The energy transfer efficiency increases with Yb 3+ concentration to reach 86% with 0.5Pr 3+ –10Yb 3+ co-doping (in mol%). However, the quenching of the Yb 3+ emission strongly reduces the efficiency of the downconversion process: the decay time values decrease from 600 µs (x=0.5 mol%) to 85 µs (x=10 mol%). - Highlights: • We synthesized 0.5Pr 3+ –xYb 3+ co-doped ZBLA glasses (from x=0 to 10 mol %). • Photoluminescence of Yb 3+ was observed at 980 nm under blue excitation. • Time resolved measurements have been performed in the visible and near infrared. • Energy transfer efficiency from Pr 3+ to Yb 3+ reaches 86% in 0.5 Pr 3+ –10Yb 3+ glass

Spectral-kinetic characteristics of Pr3+ luminescence in LiLuF4 host upon excitation in the UV-VUV range

International Nuclear Information System (INIS)

Stryganyuk, G.; Zimmerer, G.; Shiran, N.; Voronova, V.; Nesterkina, V.; Gektin, A.; Shimamura, K.; Villora, E.; Jing, F.; Shalapska, T.; Voloshinovskii, A.

2008-01-01

Spectral-kinetic study of Pr 3+ luminescence has been performed for LiLuF 4 :Pr(0.1 mol%) single crystal upon the excitation within 5-12 eV range at T=8 K. The fine-structure of Pr 3+ 4f 2 →4f 5d excitation spectra is shown for LiLuF 4 :Pr(0.1 mol%) to be affected by the efficient absorption transitions of Pr 3+ ions into 4f 5d involving 4f 1 core in the ground state. Favourable conditions have been revealed in LiLuF 4 :Pr(0.1 mol%) for the transformation of UV-VUV excitation quanta into the visible range. Lightly doped LiLuF 4 :Pr crystals are considered as the promising luminescent materials possessing the efficient Pr 3+3 P 0 visible emission upon UV-VUV excitation. The mechanism of energy transfer between Lu 3+ host ion and Pr 3+ impurity is discussed

Structural, electrical and magnetic properties of Sb-doped Pr2/3Ba1/3MnO3 perovskite manganites

International Nuclear Information System (INIS)

Sen, Vikram; Panwar, Neeraj; Bhalla, G.L.; Agarwal, S.K.

2007-01-01

We report here the electrical, magnetic and micro-structural features of the Sb-doped (nominally at Mn-sites) Pr 2/3 Ba 1/3 MnO 3 perovskite manganites. Pristine material shows two insulator-metal (I-M) like transitions in the resistivity-temperature (ρ-T) behaviour. While the higher temperature transition (T P1 ) at ∼195 K is reminiscent of the usual metal-insulator transition, the lower temperature transition (T P2 ) at ∼160 K has been ascribed to the grain boundary (GB) effects arising out of the ionic size mismatch between the ions present at the rare-earth site (Pr and Ba). With Sb doping at the Mn-site, both the resistivity peaks are seen to shift to lower temperatures. Room temperature resistivity and the peak values are also successively increasing with Sb doping. Scanning electron micrographs of the samples indicate a gradual increase in their grain sizes with Sb which indicates a gradual decrease in the GB density. The higher temperature insulator-metal transition (T P1 ) shift is explained on the basis of a competition between double-exchange and super-exchange mechanisms. The observed overall resistivity increase and the shift in the resistivity hump (T P2 ) with Sb are found related to the gradually decreasing GB density and the ensuing lattice strain increase at the grain boundaries. The intrinsic MR gets suppressed and the extrinsic MR gets enhanced with Sb doping. The observed low temperature resistivity upturn related to the localization of carriers, is also seen to increase with Sb

Synthesis and thermoluminescence of LaAlO3:Pr3+ to UVC radiation dosimetry

International Nuclear Information System (INIS)

Morales-Hernández, A.; Zarate-Medina, J.; Contreras-García, M.E.; Azorín-Nieto, J.; Rivera-Montalvo, T.

2016-01-01

Thermoluminescent (TL) response of trivalent praseodymium ion doped lanthanum aluminate (LaAlO 3 :Pr 3+ ) obtained by Pechini method and Spray Dryer was studied. TL response of LaAlO 3 :Pr 3+ powders submitted at 1600 °C exhibited one peak centered at 157 °C. Sensitivity of LaAlO 3 :Pr 3+ was improved in around 90 times compared with undoped LaAlO 3 . TL response as a function of wavelength showed a maximum in 230 nm. Dosimetric characteristics of LaAlO 3 :Pr 3+ under UVR radiation effects were analyzed. Evaluation of activation energy was obtained by Glow Fit v.1.3 software. Experimental results about thermoluminescent characteristics of LaAlO 3 :Pr 3+ suggest as good candidate to be employed as a complementary thermoluminescent device with other TL phosphors as aluminum oxide - Highlights: • High sensitivity of new phosphor to UVC dosimetry was is studied. • Thermoluminescence response of LaAlO 3 :Pr 3+ is presented. • LaAlO 3 :Pr 3+ is suggested as UVCR dosimeter. • TL response of LaAlO 3 :Pr 3+ has dependence on sintering temperature.

Structural chemistry and magnetic properties of Pr3-xSr1+xCrNiO8

International Nuclear Information System (INIS)

Dutton, Sian E.; Bahout, Mona; Battle, Peter D.; Tonus, Florent; Demange, Valerie

2008-01-01

Polycrystalline samples of the n=1 Ruddlesden-Popper system Pr 3-x Sr 1+x CrNiO 8 have been synthesized over the composition range 0.0 0.1 adopt the tetragonal space group I4/mmm; Pr 2.9 Sr 1.1 CrNiO 8 adopts the orthorhombic space group Fmmm. There is no evidence of Cr/Ni cation ordering in any composition. A maximum in the zero-field cooled magnetic susceptibility is observed at a temperature T f that decreases with increasing Sr content; 52≤T f (K)≤13. The frequency dependence of T f observed in a.c. susceptibility measurements, together with the analysis of neutron diffraction data, suggests that the atomic magnetic moments in these compositions adopt a spin-glass-like state below T f . - Graphical abstract: The n=1 Ruddlesden-Popper system Pr 3-x Sr 1+x CrNiO 8 (0.0< x≤1.0) has been characterized by diffraction methods and magnetometry. There is no evidence of Cr/Ni cation ordering in any composition. The atomic magnetic moments adopt a spin-glass-like state below a transition temperature that decreases from 52 K (x=0.1) to 13 K (x=1.0)

Working with Windows Vista at CERN - (IT3T/2007/3)

CERN Multimedia

CERN. Geneva

2007-01-01

IT3T/2007/3 - Travailler sur Windows Vista au CERN La présentation fournira une introduction à Windows Vista et montrera les nouvelles fonctionnalités comme le nouveau interface d’utilisateur : Windows Aero, le nouveau Windows Desktop Search et les divers améliorations de sécurité comme User Account Control. IT3T/2007/3 - Working with Windows Vista at CERN The presentation will provide a introduction to Windows Vista and demonstrate the new features such as the new Graphical User Interface including Windows Aero, the new Windows Desktop Search and various Security enhancements like the User Account Control.

Spin-Orbit Interaction and Kondo Scattering at the PrAlO3/SrTiO3 Interface

Science.gov (United States)

Mozaffari, Shirin; Guchhait, Samaresh; Markert, John

We have investigated the effect of oxygen content, in the PO2 range of 6 ×10-6 - 1 ×10-3 torr, on the spin-orbit (SO) interaction at PrAlO3/SrTiO3 interface. The most-conducting 2-D-like PrAlO3 interfaces were not as conducting as comparable LaAlO3 samples, indicating either a steric or mixed-valent effect. The least-conducting, most oxygenated PrAlO3 interface exhibits hole conductivity, a departure from the typical electron-doped behavior. For 10-5 and 10-4 torr samples, high-temperature metallic behavior is accompanied by an upturn in resistivity at low temperatures, consistent with Kondo scattering theory; analysis gives a Kondo temperature 17 K. The magnetoresistance (MR) for the low PO2-grown samples was modeled with a positive part due to weak anti-localization (WAL) from a strong SO interaction, and a negative part due to the Kondo effect. The variation of MR suggests a strong SO interaction for the 10-5 torr sample with HSO = 1.25 T in both field orientations. The WAL effect is smaller for higher PO2-grown samples, where the high-field MR is dominated by the Kondo effect.

Instability of Yb3+ and Pr3+ low-symmetry luminescence centers in gallium phosphide

International Nuclear Information System (INIS)

Kasatkin, V.A.

1985-01-01

The stability of γb 3+ and Pr 3+ low-symmetry luminescence centers formed in gallium phosphide during quenching were studied in the process of durable storage and annealing. Observation of the Yb 3+ and Pr 3+ centrer states was accomplished by the photoluminescence spectra at 18 K. It has been established that annealing in the dark under normal conditions results in a reduced integral luminescence intensity of all low-symmetry Yb 3+ and Pr 3+ centers. Annealing of quenched GaP and GaP saples at 400 K results in complete disappearance of intracenter luminescence of Pr 3+ and low-symmetry Yb 3+ centers. Decomposition during storage and low anealing temperature point to the instability of low-symmetry centers of Pr 3+ and Yb 3+ luminescence

Suured prügifirmad valmistuvad prügipuuduseks / Mirko Ojakivi

Index Scriptorium Estoniae

Ojakivi, Mirko

2010-01-01

Ragn-Sells ja Adelan Prügiveod soovivad luba jäätmete pikaajaliseks vaheladestamiseks Tallinna piiril. Ragn-Sells saaks jäätmekütusetehase planeerimise ja ehitamise ajal endale koguda ligi 35 000 t segaolmejäätmeid aastas, Adelan Prügiveod sooviks ladestada ligi 50 000 t prügi aastas

Temperature dependence of the ESR linewidth in the paramagnetic phase (T{gt}T{sub C}) of R{sub 1{minus}x}B{sub x}MnO{sub 3+{delta}} (R=La,Pr; B=Ca,Sr)

Energy Technology Data Exchange (ETDEWEB)

Rettori, C.; Rao, D.; Singley, J.; Kidwell, D.; Oseroff, S.B. [San Diego State University, San Diego, California 92182 (United States); Causa, M.T. [Centro Atomico Bariloche and Instituto Balseiro 8400, San Carlos de Bariloche (Argentina); Neumeier, J.J.; McClellan, K.J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Cheong, S. [ATT Bell Laboratories, Murray Hill, New Jersey 07974 (United States); Schultz, S. [University of California, San Diego, California 92037 (United States)

1997-02-01

Electron spin resonance (ESR) experiments in the paramagnetic phase of R{sub 1{minus}x}B{sub x}MnO{sub 3+{delta}} (R=La,Pr; B=Ca,Sr) show, for 1.1 T{sub C}{approx_lt}T{approx_lt}2T{sub C}, a linear T increase of the resonance linewidth, {Delta}H, in powders, ceramic pellets, and single crystals. Above {approximately}2T{sub C} a slowdown in the T increase of {Delta}H is observed. The data resemble the results found in other ferromagnetic insulators where the spin-lattice relaxation involves a single-phonon process. We find that the one-phonon process may account for the linear T dependence of the linewidth observed up to {approximately}2T{sub C}. A large T dependence of the resonance intensity above T{sub C} was found in all the samples studied, suggesting the existence of {ital spin clusters} in these compounds over a wide range of temperature. {copyright} {ital 1997} {ital The American Physical Society}

Pr{sup 3+1}S{sub 0}->Cr{sup 3+} energy transfer and ESR investigation in Pr{sup 3+} and Cr{sup 3+} activated SrAl{sub 12}O{sub 19} quantum cutting phosphor

Energy Technology Data Exchange (ETDEWEB)

Nie Zhaogang [BK21 Physics Program and Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Lim, Ki-Soo, E-mail: kslim@chungbuk.ac.k [BK21 Physics Program and Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Zhang Jiahua [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Wang Xiaojun [Department of Physics, Georgia Southern University, Statesboro, GA 30460 (United States)

2009-08-15

With the help of the Dexter's theory, the energy transfer mechanism from Pr{sup 3+1}S{sub 0} to Cr{sup 3+} is investigated theoretically in SrAl{sub 12}O{sub 19}:Pr{sup 3+}, Cr{sup 3+} quantum cutting phosphors. The electron spin resonance (ESR) spectra of Pr{sup 3+} and Cr{sup 3+}-doped SrAl{sub 12}O{sub 19} with magnetoplumbite structure have been studied. The Cr{sup 3+} ion is found to enter the Al4(4f) site, which is very close to the Sr(2d) site replaced by the Pr{sup 3+} ions in the host. The theoretical results indicate that the efficient Pr{sup 3+1}S{sub 0}->Cr{sup 3+} energy transfer can only take place in the intermediate mirror planes, in which for the nearest and next-nearest Pr{sup 3+}-Cr{sup 3+} pairs, both dipole-dipole and dipole-quadrupole interactions can play their parts in the transfer. Finally, an overview is given about the research on the energy transfer from Pr{sup 3+1}S{sub 0} to codopants in their co-doped materials.

Temperature dependence of the ESR linewidth in the paramagnetic phase (T>TC) of R1-xBxMnO3+δ (R=La,Pr; B=Ca,Sr)

International Nuclear Information System (INIS)

Rettori, C.; Rao, D.; Singley, J.; Kidwell, D.; Oseroff, S.B.; Causa, M.T.; Neumeier, J.J.; McClellan, K.J.; Cheong, S.; Schultz, S.

1997-01-01

Electron spin resonance (ESR) experiments in the paramagnetic phase of R 1-x B x MnO 3+δ (R=La,Pr; B=Ca,Sr) show, for 1.1 T C approx-lt T approx-lt 2T C , a linear T increase of the resonance linewidth, ΔH, in powders, ceramic pellets, and single crystals. Above ∼2T C a slowdown in the T increase of ΔH is observed. The data resemble the results found in other ferromagnetic insulators where the spin-lattice relaxation involves a single-phonon process. We find that the one-phonon process may account for the linear T dependence of the linewidth observed up to ∼2T C . A large T dependence of the resonance intensity above T C was found in all the samples studied, suggesting the existence of spin clusters in these compounds over a wide range of temperature. copyright 1997 The American Physical Society

Epitaxial growth and superconducting properties of YBa23Cu3O7 thin films and YBa2Cu3O7/Dy(Pr)Ba2Cu3O7 superlattices

International Nuclear Information System (INIS)

Triscone, J.M.; Brunner, O.; Antognazza, L.; Kent, A.D.; Fischer, O.; Karkut, M.G.

1990-01-01

The authors have prepared in situ REBa 2 Cu 3 O 7 (REBCO) (RE = Y, Pr, Dy) thin films and YBCO/Dy(Pr)BCO superlattices by single target dc planar magnetron sputtering. YBCO/DyBCO superlattices have been realized with modulation wavelength as short as 24 Angstrom, i.e., a unit cell of YBCO alternates with a unit cell of DyBCO, on average. The superconducting properties of such superlattices are indistinguishable from those of single layers. T co 's (zero resistance) are between 85 and 89K, and the residual resistivity ratios are between 2.5 and 3. In contrast to these results, when YBCO is layered with PrBCO, which is insulating, a dramatic change in the superconducting properties is observed. The authors have been able to artificially vary the coupling between single 12 Angstrom unit cell of YBCO by interposing insulating planes of PrBCO. As the YBCO layer separation increases, T c is reduced and the transition broadens showing evidence of 2-D superconducting fluctuations

Photoemission of heavy fermion superconductor PrOs4Sb12 and other Pr compounds

International Nuclear Information System (INIS)

Imada, S.; Yamasaki, A.; Sekiyama, A.; Settai, R.; Onuki, Y.; Suga, S.; Sugawara, H.; Sato, H.; Ochiai, A.

2004-01-01

Full text: Strongly correlated electronic states due to Pr 4f electrons found in several Pr compounds have recently been attracting much attention. The Pr 4f electrons are much more localized than in Ce due to the lanthanoid contraction. Therefore, the number of the Pr systems that show strong electron correlation is much smaller than Ce systems. We will present a comparative study of Pr 4f electronic states in such systems as the heavy fermion superconductor PrOs 4 Sb 12 , the Kondo system PrSn 3 and the localized 4f systems Pr 4 X 3 (X = Sb and Bi). The Pr 4f electronic state was probed by means of the Pr 3d → 4f resonant photoemission (RPES). Because the kinetic energy (E K ) of the photoelectrons is as high as ∼ 900 eV, this method is much more bulk sensitive than the 4d → 4f RPES with E K ∼ 100 eV. The energy resolution could be set to about 100 meV by utilizing the soft X-rays from BL25SU in SPring-8 and the SCIENTA SES-200 analyzer. The Pr 4f excitation spectrum of PrSn 3 was found to show a very strong intensity at the Fermi level (E F ). This can be interpreted as the Kondo resonance which has been observed in the Kondo Ce and Yb compounds. In the Pr 4f spectrum of the heavy fermion superconductor PrOs 4 Sb 12 , the intensity at E F was smaller than in PrSn 3 . This clearly shows that the Kondo temperature (T K ) is much lower in PrOs 4 Sb 12 than in PrSn 3 . We have further found a strong excitation energy dependence in the RPES line shape. In the case of Pr 4 X 3 (X = Sb and Bi), the intensity at E B was much smaller than PrSn 3 and PrOs 4 Sb 12 , which is consistent with the localized character of Pr 4f electrons in Pr 4 X 3 . The Pr 4f spectra of these localized systems are qualitatively well reproduced by a cluster model calculation that takes into account the hybridization between the Pr 4f orbital and the conduction and valence bands made up by the X p and Pr 5d states

Structural and intrinsic magnetic material parameters of Pr3(Fe,Ti)29 and Pr3(Fe,Ti)29Nx

International Nuclear Information System (INIS)

Psycharis, V.; Kalogirou, O.; Devlin, E.; Gjoka, M.; Simopoulos, A.; Niarchos, D.

1996-01-01

We report the study of the structural and the intrinsic magnetic properties of the Pr member of the newly discovered class of R 3 (Fe,Ti) 29 compounds and its nitride. The X-ray powder diffraction pattern of the alloy is indexed in monoclinic symmetry with lattice parameters a=10.647(1) A, b=8.6014(7) A, c=9.755(1) A and β=96.92(1) and the structure is described in the A2/m space group. Atomic positions and bond lengths are given. Nitrogenation results in a lattice expansion of 6.6% corresponding to ∝4 N atoms per formula unit. The Curie temperature is 392(5) K, and the saturation magnetization, the anisotropy field and the average hyperfine field at room temperature are 135.4 A m 2 /kg, 3.9 and 20.3 T, respectively. A magnetic phase transition is observed at ∝160 K. After nitrogenation the Curie temperature increases to 721(5) K, and the saturation magnetization to 174.8 A m 2 /kg, the anisotropy field 7.2 T and the average hyperfine field 30.1 T at room temperature. Moessbauer spectroscopy, X-ray powder diffraction and magnetization measurements on magnetically oriented powder samples provide evidence of the presence of an easy-cone-type magnetocrystalline anisotropy for both the parent and nitrided compounds in the temperature range 85-300 K. The cone angles calculated from the fitted Moessbauer spectra are 34 for the parent compound and 36 for the nitrided compound. (orig.)

Specific heat of rare earth cobaltates RCoO{sub 3} (R = La, Pr and Nd)

Energy Technology Data Exchange (ETDEWEB)

Thakur, Rasna, E-mail: rasnathakur@yahoo.com [Department of Physics, Barkatullah University, Bhopal 462026 (India); Srivastava, Archana [Department of Physics, Sri Sathya Sai College for Women, Bhopal 462024 (India); Thakur, Rajesh K.; Gaur, N.K. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

2012-03-05

Highlights: Black-Right-Pointing-Pointer We have reported the temperature dependence (5 K {<=} T {<=} 1000 K) of the lattice contribution to the specific heat of rhombohedral LaCoO{sub 3} and orthocobaltates RCoO{sub 3} (R = Pr and Nd). Black-Right-Pointing-Pointer The strong electron phonon interactions are present in these compounds and lattice distortions can affect them substantially. Black-Right-Pointing-Pointer Thus Rigid Ion Model (RIM) is used for the first time to study the cohesive and thermal properties of the cobaltates RCoO{sub 3} with rare earth cation (R = La, Pr and Nd). Black-Right-Pointing-Pointer The values of specific heat calculated by us have shown remarkably good agreement with corresponding experimental data. Black-Right-Pointing-Pointer In addition, the results on the temperature dependence of cohesive energy ({phi}), molecular force constant (f), Reststrahlen frequency ({upsilon}), Debye temperature ({theta}{sub D}) and Gruneisen parameter ({gamma}) are also reported. - Abstract: We have reported the temperature dependence (5 K {<=} T {<=} 1000 K) of the lattice contribution to the specific heat of rhombohedral LaCoO{sub 3} and orthocobaltates RCoO{sub 3} (R = Pr and Nd). The strong electron phonon interactions are present in these compounds and lattice distortions can affect them substantially. Thus Rigid Ion Model (RIM) is used for the first time to study the cohesive and thermal properties of the cobaltates RCoO{sub 3} with rare earth cation (R = La, Pr and Nd). The values of specific heat calculated by us have shown remarkably good agreement with corresponding experimental data. In addition, the results on the temperature dependence of cohesive energy ({phi}), molecular force constant (f), Reststrahlen frequency ({upsilon}), Debye temperature ({theta}{sub D}) and Gruneisen parameter ({gamma}) are also reported.

Induced 3d and 4f magnetism in Gd{sub 1-x}Pr{sub x}Ni{sub 2} Laves phase alloys

Energy Technology Data Exchange (ETDEWEB)

Bouziane, K [Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, Al-Khodh 123 (Oman); Carboni, C [Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, Al-Khodh 123 (Oman); Morrison, C [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

2008-01-16

The series of Gd{sub 1-x}Pr{sub x}Ni{sub 2} (x = 0.25, 0.40, and 0.60) polycrystalline samples has been investigated using x-ray diffraction and magnetometry. The x-ray diffraction measurements showed that the lattice constant and the relative intensities of the C15 superstructure I{sub 511}/I{sub 440} and I{sub 511}/I{sub 220} increase with the praseodymium content, reflecting an increasing number of ordered vacancies at the 4a sites. The temperature dependences of the zero-field cooled (M{sub ZFC}(T)) and field cooled (M{sub FC}(T)) magnetizations show that a moment is induced by the gadolinium on the Pr{sup 3+} ion and on the nickel subsystem. In the ordered phase both induced moments are antiparallel to that of the Gd{sup 3+} ion. A cusp is observed at a temperature T{sub max} in the M{sub ZFC}(T) curve. Both critical temperatures T{sub c} and T{sub max} are found to decrease with increasing praseodymium content, indicating a reduction in strength of the antiparallel coupling for Gd-Pr and Gd-Ni pairs.

Selective recognition of Pr3+ based on fluorescence enhancement sensor

International Nuclear Information System (INIS)

Ganjali, M.R.; Hosseini, M.; Ghafarloo, A.; Khoobi, M.; Faridbod, F.; Shafiee, A.; Norouzi, P.

2013-01-01

(E)-2-(1-(4-hydroxy-2-oxo-2H-chromen-3-yl)ethylidene) hydrazinecarbothioamide (L) has been used to detect trace amounts of praseodymium ion in acetonitrile–water solution (MeCN/H 2 O) by fluorescence spectroscopy. The fluorescent probe undergoes fluorescent emission intensity enhancement upon binding to Pr 3+ ions in MeCN/H 2 O (9/1:v/v) solution. The fluorescence enhancement of L is attributed to a 1:1 complex formation between L and Pr 3+ , which has been utilized as the basis for selective detection of Pr 3+ . The sensor can be applied to the quantification of praseodymium ion with a linear range of 1.6 × 10 −7 to 1.0 × 10 −5 M. The limit of detection was 8.3 × 10 −8 M. The sensor exhibits high selectivity toward praseodymium ions in comparison with common metal ions. The proposed fluorescent sensor was successfully used for determination of Pr 3+ in water samples. - Highlights: • A new fluorescent sensor is introduced as a selective probe for Pr 3+ detection. • Fluorescent intensity of the chemical probe enhances upon binding to Pr 3+ ion. • The sensor can be used for Pr 3+ determination in the range of 1.6 × 10 −7 –1.0 × 10 −5 M

Energy Transfer between Er3+ and Pr3+ for 2.7 μm Fiber Laser Material

Directory of Open Access Journals (Sweden)

Xiangtan Li

2014-01-01

Full Text Available Energy transfer mechanisms between Er3+ and Pr3+ in Er3+/Pr3+ codoped germinate glass are investigated in detail. Under 980 nm LD pumping, 2.7 μm fluorescence intensity enhanced greatly. Meanwhile, 1.5 μm lifetime and fluorescence were suppressed deeply due to the efficient energy transfer from Er3+:4I13/2 to Pr3+:3F3,4, which depopulates the 4I13/2 level and promotes the 2.7 μm transition effectively. The obvious change in J-O parameters indicates that Pr3+ influences the local environment of Er3+ significantly. The increased spontaneous radiative probability in Er3+/Pr3+ glass is further evidence for enhanced 4I11/2 → 4I13/2 transition. The Er3+:4I11/2→Pr3+:1G4 process is harmful to the population accumulation on 4I11/2 level, which inhibits the 2.7 μm emission. The microscopic energy transfer coefficient of Er3+:4I13/2→Pr3+:3F3,4 is 42.25 × 10−40 cm6/s, which is 11.5 times larger than that of Er3+:4I11/2→Pr3+:1G4. Both processes prefer to be non-phonon assisted, which is the main reason why Pr3+ is so efficient in Er3+:2.7 μm emission.

Eff icient energy back transfer from Ce{sup 3+} 5d state to Pr{sup 3+} {sup 1}D{sub 2} level in Lu{sub 3}Al{sub 5}O{sub 12} upon Pr{sup 3+} 4f5d excitation

Energy Technology Data Exchange (ETDEWEB)

Dan Wu [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, Jilin (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Hao, Zhendong; Zhang, Xia; Pan, Guo-Hui; Luo, Yongshi; Zhang, Ligong; Zhao, Haifeng [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, Jilin (China); Zhang, Jiahua, E-mail: zhangjh@ciomp.ac.cn [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, Jilin (China)

2017-06-15

The step energy transfers from Pr{sup 3+} 4f5d state to Ce{sup 3+} 5d state followed by energy back transfer from Ce{sup 3+} 5d state to Pr{sup 3+} {sup 1}D{sub 2} level are studied. The Ce{sup 3+}→Pr{sup 3+} energy back transfer upon Pr{sup 3+} 4f5d excitation is found to be more efficient than the normal Ce{sup 3+}→Pr{sup 3+} energy transfer upon Ce{sup 3+} 5d excitation. The efficient energy back transfer is attributed to preferential excitation of the Ce{sup 3+} ion with an adjacent Pr{sup 3+} surrounding in Pr{sup 3+}→Ce{sup 3+} energy transfer of the first step, whereas Ce{sup 3+} is excited randomly in the normal energy transfer. The efficiencies of Ce{sup 3+}→Pr{sup 3+} energy back transfer as a function of Ce{sup 3+} and Pr{sup 3+} concentration are evaluated, respectively.

Sol–gel synthesis and photoluminescence of CaTi1–x Zrx O3: Pr 3 ...

Indian Academy of Sciences (India)

The strongest red excitation obtained from CaTi1–ZrO3 : Pr3+ ( = 4/300) and CaTi1–ZrO3 : Pr3+ ( = 5/300) possesses the strongest emission at 610 nm, similar to the intensities of Ca(Ti1–Zr)O3 : Pr3+ ( = 3/300, 4/300, 6/300), which may be corresponded to the cell parameters of CaTi1–ZrO3 : Pr3+.

Praseodymium valency from crystal structure in Pr-Ba-Cu-O and (Y-Pr)-Ba-Cu-O single crystals

International Nuclear Information System (INIS)

Collin, G.; Albouy, P.A.; Monod, P.; Ribault, M.

1990-01-01

The substitution of Pr to Y leads to materials with a general formula (Y 1-v Pr v ) (Ba 2-x Pr x ) (Cu 3-y vac y ) O 6+x/2-y+z and with a structural transition around v + x' ∼ 0.5. For v + x 0.5 the crystals are tetragonal, La 1.5 Ba 1.5 Cu 3 O 7±z type, with the characteristic tri-twinning of this phase. The Pr valency, in the range 3-3.2 + depending on preparation conditions, is determined from interatomic distances. Orthorhombic crystals of Pr Ba Cu O prepared at high temperatures exhibit a high amount of defects, y ∼ 0.25 on the Cu(1) site and are semiconductors with a T -1/4 activation law attributed to the praseodymium valence fluctuation

Evidence for a helical and a chiral phase transition in the Gd(hfac)3NITiPr magnetic specific heat

International Nuclear Information System (INIS)

Cinti, F.; Rettori, A.; Barucci, M.; Olivieri, E.; Risegari, L.; Ventura, G.; Caneschi, A.; Gatteschi, D.; Rovai, D.; Pini, M.G.; Affronte, M.; Mariani, M.; Lascialfari, A.

2007-01-01

New specific heat data taken at very low temperatures (0.03 3 NITiPr show a clear λ anomaly at T N =0.039K signaling the onset of the 3D helimagnetic phase. They match fairly well with previously reported data which showed the onset of the chiral phase transition at T 0 =2.08K. Also new magnetic susceptibility data taken in the neighborhood at T 0 are repeated

Sotsiaalmeedia osatähtsus PR tööriistana kasvab : Baltimaade, Poola ja Valgevene suhtekorraldajad / Villy Paimets

Index Scriptorium Estoniae

Paimets, Villy, 1972-

2016-01-01

Leedu suhtekorraldajate ühendus tegi uuringu Leedu ja tema naaberriikide PR turgude hetkeseisust ja tulevikuväljavaadetest. Põhjalikumalt uuriti Eesti, Läti, Leedu, Poola ja Valgevene turge. Uuringu tulemuste kohta avaldavad arvamust SEB kommunikatsioonijuht Evelin Allas, PR-ettevõtja ja -õppejõud Mart Soonik ning kaitseväe meediasuhete juhina ja suhtekorraldusfirmas PR Partner strateegilise konsultandina töötanud Riigikogi IRL-i fraktsiooni meedianõunik Ingrid Mühling

The Pr and Ca Substitution in GdBa2Cu3O7- & delta

Directory of Open Access Journals (Sweden)

H. S. H.

2001-12-01

Full Text Available   The granular Gd1-x-zPrxCazBa2Cu3O7-δ high-temperature cuprate samples with 0.0 ≤ x ≤ 0.3 and 0.0≤ x ≤ 0.35 are prepared by standard solid state reaction and characterized by XRD and SEM techniques. The BaCuO2 and impurity phases are less than 1% in the samples having high levels of pr and Ca concentrations. The electrical resistivity measurements show a nonlinear reduction in Tc(x,z=etc versus x. Moreover, the Tc(z curve with x=0 is nonlinear and aplateau appears at z≈ 0.05-0.015. For Pr-Ca-doped samples with a constant concentration of Pr, Tc increases with the increase of Ca up to an optimum value of Ca doping and then in decreases. Based on these observations, we suggest that hole filling and hole localization the main effects of Pr ion substiution. The magnetic measurements indicate that the value of Hc1 is in the order of 10 mT. The mangetoresistance measurements have been measured and analyzed. The superconducting transition region is broadened by the application of magnetic field. The experimental data near the onsen of superconductivity are fitted with the Ambegakor and Halperin (AH phase-slip model. We observe that the AH parameter,γ (H, depends not only on the temperature and the magnetic field, but also on the Pr and Ca ions concentrations. It is observed that the critical current density increases with Ca substitution and decreases with Pr substitution in Gd-123 system. We suggest that the Pr ion substitution probably enhances the weak link, but the Ca ion acts as flux pinning center in the GdPrCa-123 system.

Rats and mice immunised with chimeric human/mouse proteinase 3 produce autoantibodies to mouse Pr3 and rat granulocytes

NARCIS (Netherlands)

van der Geld, Ymke M.; Hellmark, Thomas; Selga, Daina; Heeringa, Peter; Huitema, Minke G.; Limburg, Pieter C.; Kallenberg, Cees G. M.

2007-01-01

Aim: In this study, we employed chimeric human/ mouse Proteinase 3 ( PR3) proteins as tools to induce an autoantibody response to PR3 in rats and mice. Method: Rats and mice were immunised with recombinant human PR3 ( HPR3), recombinant murine PR3 ( mPR3), single chimeric human/ mouse PR3 ( HHm,

The influence of Pr3+ co-doping on the photoluminescence and cathodoluminescence properties of SiO2:Eu3+/Tb3+

CSIR Research Space (South Africa)

Mhlongo, GH

2011-07-01

Full Text Available Tb3+-Pr3+, and Eu3+-Pr3+ ion pairs co-doped in a SiO2 matrix were prepared by a sol-gel method. Co-doping of Eu3+ and Tb3+ ions with Pr3+ in SiO2 resulted in the quenching of Eu3+ and Tb3+ emissions with increasing Pr3+ concentrations. The quenching...

Satellite line mapping in Eu3+–Ce3+ and Pr3+–Ce3+ codoped Y2SiO5

International Nuclear Information System (INIS)

Serrano, D.; Karlsson, J.; Zheng, L.; Dong, Y.; Ferrier, A.; Goldner, P.; Walther, A.; Rippe, L.; Kröll, S.

2016-01-01

In this work we perform a high-resolution spectroscopic investigation of Eu 3+ –Ce 3+ and Pr 3+ –Ce 3+ codoped Y 2 SiO 5 crystals. Satellite line spectra were recorded at low temperatures around the Eu 3+ : 7 F 0 → 5 D 0 and the Pr 3+ : 3 H 4 → 1 D 2 transitions. It is observed that the incorporation of Ce 3+ as a codopant notably changes the Eu 3+ and Pr 3+ satellite line patterns. Satellite lines measured in singly doped Eu 3+ :Y 2 SiO 5 were found at the same spectral positions in Eu 3+ –Ce 3+ codoped crystals. These coincident lines were concluded to be due to pairs of Eu 3+ ions. Extra satellite lines appeared in the codoped crystals, which were assigned to Ce 3+ related structures such as Ce 3+ –Eu 3+ pairs. The analysis of the Pr 3+ satellite line spectra presents further challenges. Satellite lines associated to Pr 3+ pairs show weaker intensity, presumably due to the efficient quenching of the Pr 3+1 D 2 emission through cross-relaxation paths ( 1 D 2 → 1 G 4 ; 3 H 4 → 3 F 4 ). The investigation of the Eu 3+ and Pr 3+ satellite line patterns in Y 2 SiO 5 is particularly interesting for their exploitation in rare-earth based quantum computation schemes. - Highlights: • We recorded Eu and Pr satellite lines in Y 2 SiO 5 with and without Ce as a codopant. • The presence of Ce leads to the appearance of extra satellite lines in the spectra. • The satellite lines are associated to minor crystal sites such as ion pairs. • Less than 100 ion pairs were detected per satellite line. • The exploitation of the satellite line structure is proposed for quantum computing.

The thermodynamic characteristics of vaporization in the NaI-PrI3 system

Science.gov (United States)

Motalov, V. B.; Kudin, L. S.; Markus, T.

2009-05-01

The vaporization of the NaI-PrI3 quasi-binary system was studied by high-temperature mass spectrometry over the whole concentration range. At 623-994 K, saturated vapor contained not only (NaI) n and (PrI3) n molecules ( n = 1, 2) and Na+(NaI) n ( n = 0-4) and I-(PrI3) n ( n = 1-2) ions but also mixed molecular and ionic associates recorded for the first time (NaPrI4, Na2PrI5, NaPrI{3/+}, Na2PrI{4/+}, Na3PrI{5/+}, Na4PrI{6/+}, NaPrI{5/-}, and NaPr2I{8/-}). The partial vapor pressures of molecules were calculated, and the equilibrium constants of the dissociation of neutral and charged associates were measured. The enthalpies of molecular and ion-molecular reactions were determined, and the enthalpies of formation of gaseous molecules and ions were obtained.

Current dependent angular magnetoresistance in strongly Pr-doped Y Ba2Cu3O7-δ single crystal

International Nuclear Information System (INIS)

Sandu, V; Gyawali, P; Katuwal, T; Almasan, C C; Taylor, B J; Maple, M B

2009-01-01

We report a strong dependence of the angular magnetoresistance (AMR) on the current density in Y Ba 2 Cu 3 O 7-δ single crystal above the critical temperature T c = 13 K for any applied field up to 14 T. We estimated the current dependence from the angular dependence of the top resistance R top , as measured on the face where the current is applied, and the bottom resistance R bot as measured on the opposite face. At any temperature, both below and above T c , R top decreases as the field becomes parallel to the current and ab-plane with an angle dependence that suggests an important contribution arising from the vortex flow. R bot evolves from a monotonic to nonmonotonic angle dependence with three minima and two maxima in the angle range 0 - 180 deg. as the temperature increases. For less Pr-doped samples, Y 0.58 Pr 0.42 Ba 2 Cu 3 O 7-δ (T c = 39 K) and Y 0.68 rP 0.32 Ba 2 Cu 3 O 7-δ (T c = 55 K), where the interplane resistivity is much lower, both R top and R bot follow the same monotonic angle dependence in all temperature and field range.

Effects of Er3+ and Pr3+ Substitution on Structural, Dielectric, Ferroelectric and Photoluminescence Properties of the BaTi0.9Zr0.1O3 Ceramic

Science.gov (United States)

Zouari, I.; Sassi, Z.; Seveyrat, L.; Perrin, V.; Zghal, S.; Abdelmoula, N.; Lebrun, L.; Khemakhem, H.

2017-07-01

BaTi0.9Zr0.1O3 (BZT), Ba1- x Ln2 x/3□ x/3Ti0.9Zr0.1O3 (with x = 0.5% mol and Ln = Er3+) (BZT-Er) and Ba1- x Ln2 x/3□ x/3Ti0.9Zr0.1O3 (with x = 0.5% mol and Ln = Pr3+) (BZT-Pr) were prepared via the conventional solid-state reaction method. X-ray diffraction showed that all these ceramics were in the single perovskite phase at room temperature (RT). The temperature dependence of dielectric behavior was investigated in the temperature range 25-225°C and exhibited a classical ferroelectric behavior. A slight decrease of the Curie temperature ( T C) with Pr3+ and Er3+ substitution was observed in addition to an increase in the maximum dielectric permittivity ( \\varepsilon_{r {max} }^' }} ) of about 40% for the BZT-Er. At RT, the ferroelectric and piezoelectric coefficients were decreased for BZT-Pr, but were maintained for BZT-Er with a piezoelectric coefficient ( d 33) of 185 pC/N, a planar electromechanical coupling factor of 30%, and a remanent polarization of 11.6 μC/cm2. The Raman bands as a function of temperature confirmed the paraelectric-ferroelectric phase transition of all those ceramics. The photoluminescence spectra showed that strong red (615 nm and 645 nm) and bright green (523 nm and 545 nm) emission bands were obtained, under excitation by laser at 488 nm at RT, for BZT-Pr and BZT-Er, respectively. These multifunctional materials showed a significant technological promise in coupling device applications.

Liquid-vapor equilibrium in LaCl3-LuCl3 and PrCl3-NdCl3 systems

International Nuclear Information System (INIS)

Nisel'son, L.A.; Lyzlov, Yu.N.; Solov'ev, S.I.

1978-01-01

The liquid-vapour equilibrium in the systems LaCl 3 -LuCl 3 and PrCl 3 -NdCl 3 was studied by the boiling-point method. It was established that the system LaCl 3 -LuCl 3 is near-ideal. In the PrCl 3 -NdCl 3 system, a considerable positive deviation from the ideal with the formation of an azeotrope was detected. The azeotrope has a ''smeared-out'' minimum, which falls on a mixture containing approximately 65 mol.% neodymium trichloride. The boiling point of this mixture at a pressure of 1 mm Hg is approximately 975 deg C. The relative volatility coefficients in both systems were studied by the Raleigh distillation method. The presence of the azeotrope in the system PrCl 3 -NdCl 3 is confirmed by the nature of the dependence of the relative volatility coefficient on the composition of the mixture

Proximity effect in YBa2Cu3O7/Y0.6Pr0.4Ba2Cu3O7/YBa2Cu3O7 junctions

International Nuclear Information System (INIS)

Polturak, E.; Koren, G.; Cohen, D.; Aharoni, E.; Deutscher, G.

1991-01-01

We report critical-current measurements in all high-T c superconducting-normal-superconductor junctions using Y 0.6 Pr 0.4 Ba 2 Cu 3 O 7 (with T cN =40 K) as the normal metal. Above T cN , we find a clear exponential dependence of I c on the thickness of the barrier which is characteristic of the proximity effect. The order-parameter decay length is about 120 A for T>60 K, and it diverges as T cN is approached. We estimate that ξ 0 for this material is 80±25 A

Technical attainment, practical success and practical knowledge: hermeneutical bases for child nursing care Éxito técnico, éxito práctico y sabiduría práctica: bases conceptuales hermenéuticas para el cuidado de enfermería al niño Êxito técnico, sucesso prático e sabedoria prática: bases conceituais hermenêuticas para o cuidado de enfermagem à criança

Directory of Open Access Journals (Sweden)

Débora Falleiros de Mello

2009-08-01

Full Text Available This reflective study aimed to present some aspects of the concepts technical attainment, practical success and practical knowledge, with a view to a broader understanding of child nursing care. Health care is considered in the perspective of reconstructive practices, characterized as contingencies, highlighting the importance of the connection between technical attainment and practical success and the valuation of practical knowledge, based on philosophical hermeneutics, in the context of practical philosophy. Child health nursing can deal with technical attainment and practical success jointly, and also understand practical knowledge in the longitudinality of care. Health promotion, disease prevention, recovery and rehabilitation of child health should be indissociably associated with contextualized realities, shared between professionals and families, aiming to follow the child's growth and development, produce narratives, identify experiences, choices and decision making to broaden health care.Este estudio reflexivo buscó presentar algunos aspectos de los conceptos éxito técnico, éxito práctico y sabiduría práctica para ampliar la comprensión del cuidado de enfermería al niño. El cuidado en salud es entendido bajo la perspectiva de las prácticas reconstructivas y con carácter de contingencia, destacando la importancia de la conexión entre éxito técnico y éxito práctico y la valorización de la sabiduría práctica, provenientes de la hermenéutica filosófica, en el ámbito de la filosofía práctica. La enfermería en salud del niño puede lidiar articuladamente con el éxito técnico y el éxito práctico y comprender la sabiduría práctica en la extensión longitudinal del cuidado. La promoción de la salud, prevención de enfermedades, recuperación y rehabilitación de la salud del niño, de forma indisociable, deben estar en consonancia con realidades contextualizadas y compartidas entre profesionales y familias

Spectroscopic properties of Pr{sup 3+} ions embedded in lithium borate glasses

Energy Technology Data Exchange (ETDEWEB)

Ramteke, D.D. [Department of Applied Physics, Visvesvaraya National Institute of Technology, Nagpur 440010 (India); Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa); Gedam, R.S., E-mail: rupesh_gedam@rediffmail.com [Department of Applied Physics, Visvesvaraya National Institute of Technology, Nagpur 440010 (India)

2016-01-01

A series of lithium borate glasses with different Pr{sup 3+} contents were prepared by the melt quench technique to explore the new material for solid state light applications. We found that the addition of Pr{sup 3+} ions in the glass matrix has a profound effect on the properties of the glasses. The presence of Pr{sup 3+} ions in the glass matrix created various absorption bands compared to the base glass. These bands were due to the ground state ({sup 3}H{sub 4}) of the Pr{sup 3+} to the various excited states. Optical energy band gap was calculated by Tauc's method which showed a decreasing trend with an increase in the Pr{sup 3+} content. This might be due to structural changes when the glass structure became rigid due to the Pr{sup 3+} ions and this was confirmed by the density results. Rigidity of the glass structure was further confirmed by the Fourier transformed infrared results. The excitation spectra showed bands at {sup 3}H{sub 4}→{sup 3}P{sub 2}, {sup 3}P{sub 1} and {sup 3}P{sub 0} nm. The {sup 3}H{sub 4}→{sup 3}P{sub 2} band was used to study the unresolved {sup 1}D{sub 2}→{sup 3}H{sub 4} and {sup 3}P{sub 0}→{sup 3}H{sub 6} transitions of the Pr{sup 3+} ions.

Evidence for a helical and a chiral phase transition in the Gd(hfac){sub 3}NITiPr magnetic specific heat

Energy Technology Data Exchange (ETDEWEB)

Cinti, F. [INFM and Department of Physics, University of Florence, 50019 Sesto Fiorentino (Italy)]. E-mail: fabio.cinti@fi.infn.it; Rettori, A. [INFM and Department of Physics, University of Florence, 50019 Sesto Fiorentino (Italy); Barucci, M. [INFM and Department of Physics, University of Florence, 50019 Sesto Fiorentino (Italy); Olivieri, E. [INFM and Department of Physics, University of Florence, 50019 Sesto Fiorentino (Italy); Risegari, L. [INFM and Department of Physics, University of Florence, 50019 Sesto Fiorentino (Italy); Ventura, G. [INFM and Department of Physics, University of Florence, 50019 Sesto Fiorentino (Italy); Caneschi, A. [Department of Inorganic Chemistry, University of Florence, 50019 Sesto Fiorentino (Italy); Gatteschi, D. [Department of Inorganic Chemistry, University of Florence, 50019 Sesto Fiorentino (Italy); Rovai, D. [Department of Inorganic Chemistry, University of Florence, 50019 Sesto Fiorentino (Italy); Pini, M.G. [ISC-CNR, 50019 Sesto Fiorentino (Italy); Affronte, M. [INFM-S3 and Department of Physics, University of Modena, 41100 Modena (Italy); Mariani, M. [INFM and Department of Physics, University of Pavia, 27100 Pavia (Italy); Lascialfari, A. [Istituto di Fisiologia e Chimica Biologica, University of Milano, Milano (Italy); INFM and Department of Physics, University of Pavia, 27100 Pavia (Italy)

2007-03-15

New specific heat data taken at very low temperatures (0.03<T<0.18K) in quasi one-dimensional helimagnet Gd(hfac){sub 3}NITiPr show a clear {lambda} anomaly at T{sub N}=0.039K signaling the onset of the 3D helimagnetic phase. They match fairly well with previously reported data which showed the onset of the chiral phase transition at T{sub 0}=2.08K. Also new magnetic susceptibility data taken in the neighborhood at T{sub 0} are repeated.

Evaluation of critical distances for energy transfer between Pr{sup 3+} and Ce{sup 3+} in yttrium aluminium garnet

Energy Technology Data Exchange (ETDEWEB)

Zeng, Peng; Wei, Xiantao; Yin, Min; Chen, Yonghu, E-mail: yhuchen@ustc.edu.cn [Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China, No. 96 Jinzhai Road, Hefei, Anhui 230026 (China); Zhou, Shaoshuai [Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China, No. 96 Jinzhai Road, Hefei, Anhui 230026 (China); Department of Physics, Qufu Normal University, Qufu, Shandong 273165 (China)

2016-09-07

A series of Pr{sup 3+}/Ce{sup 3+} doped yttrium aluminium garnet (Y{sub 3}Al{sub 5}O{sub 12} or simply YAG) phosphors were synthesized to investigate the energy transfer between Pr{sup 3+} and Ce{sup 3+} for their potential application in a white light-emitting diode and quantum information storage and processing. The excitation and emission spectra of YAG:Pr{sup 3+}/Ce{sup 3+} were measured and analyzed, and it revealed that the reabsorption between Pr{sup 3+} and Ce{sup 3+} was so weak that it can be ignored, and the energy transfer from Pr{sup 3+} (5d) to Ce{sup 3+} (5d) and Ce{sup 3+} (5d) to Pr{sup 3+} ({sup 1}D{sub 2}) did occur. By analyzing the excitation and the emission spectra, the energy transfer from Pr{sup 3+} (5d) to Ce{sup 3+} (5d) and Ce{sup 3+} (5d) to Pr{sup 3+} ({sup 1}D{sub 2}) was examined in detail with an original strategy deduced from fluorescence dynamics and the Dexter energy transfer theory, and the critical distances of energy transfer were derived to be 7.9 Å and 4.0 Å for Pr{sup 3+} (5d) to Ce{sup 3+} (5d) and Ce{sup 3+} (5d) to Pr{sup 3+} ({sup 1}D{sub 2}), respectively. The energy transfer rates of the two processes of various concentrations were discussed and evaluated. Furthermore, for the purpose of sensing a single Pr{sup 3+} state with a Ce{sup 3+} ion, the optimal distance of Ce{sup 3+} from Pr{sup 3+} was evaluated as 5.60 Å, where the probability of success reaches its maximum value of 78.66%, and meanwhile the probabilities were evaluated for a series of Y{sup 3+} sites in a YAG lattice. These results will be of valuable reference for achievement of the optimal energy transfer efficiency in Pr{sup 3+}/Ce{sup 3+} doped YAG and other similar systems.

Electronic and crystal structure, EPR and magnetic investigations of YF{sub 3}:1%RE (RE = Pr, Ho, Er and Tm) and LaF{sub 3}:1%Pr nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Talik, E., E-mail: talik@us.edu.pl [Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Zajdel, P.; Guzik, A.; Skrzypek, D. [Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Lipińska, L.; Michalska, M. [Institute of Electronic Materials Technology, ul. Wólczyńska 133, 01-919 Warszawa (Poland)

2014-12-15

Highlights: • The thermal decomposition method was successfully applied for the first time in order to obtain the good quality nanocrystals of YF{sub 3}:1%RE. • For YF{sub 3}:1%Pr and LaF{sub 3}:1%Pr extra phase PrF{sub 3} was found. • The XPS energy gap is about 10 eV. • Surface contamination can be responsible for the deterioration of the optical properties of the composites. - Abstract: A new chemical synthesis route by a thermal decomposition of nitrates and acetates, preceded by solution displacement reaction, was successfully applied to obtain the YF{sub 3}:1%RE (RE = Pr, Ho, Er and Tm) and LaF{sub 3}:1%Pr nanocrystals. The samples were characterized by the following methods: X-ray diffraction, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), magnetic susceptibility thermal dependence measurements and electron paramagnetic resonance (EPR). The obtained YF{sub 3}:1%RE (RE = Pr, Ho, Er and Tm) materials crystallized with orthorhombic symmetry, whilst LaF{sub 3}:1%Pr exhibits hexagonal structure. Chemical composition determined by EDX, XPS and magnetic measurements was close to nominal formula. SEM images show the nanometric size of the grains. Surface contamination can be suggested to be responsible for the deterioration of the optical properties of the composites.

Electronic structure of PrBa2Cu3O7

International Nuclear Information System (INIS)

Singh, D.J.

1994-01-01

Electronic-structure calculations, within the local spin density approximation (LSDA), are reported for PrBa 2 Cu 3 O 7 . Significant charge transfer from the Pr ions to both the CuO 2 planes and the chains is found relative to YBa 2 Cu 3 O 7 . This supports hole depletion explanations for the insulating character of PrBa 2 Cu 3 O 7 . The LSDA electronic structure shows a prominent ''ridge'' Fermi surface analogous to that in YBa 2 Cu 3 O 7 , but broader. It is proposed that high-resolution positron measurements of this width may provide a useful test of hole depletion models

Synthesis and growth of single crystals of PrCl3

International Nuclear Information System (INIS)

Pei, Jen Shieh.

1984-01-01

An efficient method for growth of high optical quality single crystals of PrCl 3 . The method consists in careful drying of the hydrated chloride, PrCl 3 . 7H 2 O, with a protective atmosphere of anhydrous HCl and Ar. A subsequent growth was done by the zone melting technique. The hydrated chloride had prepared from dissolution of the oxide Pr 6 O 11 in hydrochloric acid. The grown crystals had characterized fluorescence and x-ray diffraction measurements. (Author) [pt

Magnetic properties of the germanides RE3Pt4Ge6 (RE=Y, Pr, Nd, Sm, Gd-Dy)

International Nuclear Information System (INIS)

Eustermann, Fabian; Eilers-Rethwisch, Matthias; Renner, Konstantin; Hoffmann, Rolf-Dieter; Poettgen, Rainer; Janka, Oliver; Oldenburg Univ.

2017-01-01

The germanides RE 3 Pt 4 Ge 6 (RE=Y, Pr, Nd, Sm, Gd-Dy) have been synthesized by arc-melting of the elements followed by inductive annealing to improve the crystallinity and allow for structural order. The compounds have been studied by powder X-ray diffraction; additionally the structure of Y 3 Pt 4 Ge 6 has been refined from single-crystal X-ray diffractometer data. It exhibits a (3+1)D modulated structure, indicating isotypism with Ce 3 Pt 4 Ge 6 . The crystal structure can be described as an intergrowth between YIrGe 2 - and CaBe 2 Ge 2 -type slabs along [100]. Temperature-dependent magnetic susceptibility measurements showed Pauli paramagnetism for Y 3 Pt 4 Ge 6 and Curie-Weiss paramagnetism for Pr 3 Pt 4 Ge 6 and Nd 3 Pt 4 Ge 6 . Sm 3 Pt 4 Ge 6 exhibits van Vleck paramagnetism, while antiferromagnetic ordering at T N =8.1(1) K and T N =11.0(1) K is observed for Gd 3 Pt 4 Ge 6 and Tb 3 Pt 4 Ge 6 , respectively.

Calculation of effective Coulomb interaction in PrCoO3

Science.gov (United States)

Dutta, Paromita; Lal, Sohan; Pandey, Sudhir K.

2018-04-01

It is very essential to know the suitable value of effective coulomb interaction (Ueff) which will be material specific, if one wants to learn about various physical features of strongly correlated systems in an extensive manner. In present work, the constrained density function theory (DFT) method has been used to evaluate the suitable Ueff value between the localized electrons for 3d and 4f orbitals in strongly correlated system. For the evaluation of suitable Ueff, the d/f-linearization energy (Ed/f) is very important and is found to be >= 44 eV above Fermi level. The Ueff is predicted by local density approximation (LDA) functional for both the impurity atoms separately are found to be Co (3d electrons) ˜ 6.3 eV and Pr (4f electrons) ˜ 7.0 eV for Ed/f ˜ 44 eV above Fermi level. The Ueff value for Pr (4f electrons) is higher than Co (3d electrons). This indicates that Pr 4f electrons is more localized than Co 3d electrons in PrCoO3 compound.

Potentiometric and spectral studies of complex formation of La(3), Pr(3) and Lu(3) with aspartic acid and asparagine

International Nuclear Information System (INIS)

Wojciechowska, A.; Lomozik, L.; Zielinski, S.

1987-01-01

The composition and stability of La 3+ , Pr 3+ and Lu 3+ complexes with aspartic acid and asparagine were analysed. The formation of complexes of the type ML and MHL was determined for La 3+ and Pr 3+ with aspartic acid, and of the type MHL for Lu 3+ with aspartic acid. For La 3+ , Pr 3+ and Lu 3+ with asparagine the formation of ML(OH) complexes was observed. By means of 1 HNMR and 13 CNMR studies the participation in the coordination of both -COOH groups was determined for aspartic acid, whereas for asparagine the participation of the -COOH group was determined in complexes with La 3+ , Pr 3+ , and of the -COOH and the -NH 2 groups in the complex with Lu 3+ . (Author)

Atom-replaced pins in a Y-based superconductor—single-crystalline perovskite structure including both PrBa2Cu3O7‑x and YBa2Cu3O7‑y

Science.gov (United States)

Hayashi, Mariko; Araki, Takeshi; Ishii, Hirotaka; Nishijima, Gen; Matsumoto, Akiyoshi

2018-05-01

Metal organic deposition using trifluoroacetates (TFA-MOD) provides many uniform superconductors on long metal tapes. The large numbers of long wires have been applied for power grids or superconducting fault current limiters. The related applications worked for a long time without fatal trouble. The quasi-liquid produced during the firing process assisted the perfectly uniform structure in TFA-MOD. On the other hand, when it was desired to introduce artificial pinning centers, the quasi-liquid also enlarged the diameter of the artificial pinning centers to several tens of nanometers. In other words, due to the nature of TFA-MOD, there is very little chance of using TFA-MOD to prepare several nm-sized artificial pinning centers. By proposing atom-replaced pins (ARPs), we aim to overcome the impasse. ARPs are realized by replacing yttrium (Y) with praseodymium (Pr) whose valence number changes from 3+ to approximately 4+. Analytical results suggested that Pr makes pinning centers on a PrBa2Cu3O7‑x (PrBCO) unit cell, and the weak-linked superconductivity derived from PrBCO extends to the adjacent unit cells in the a/b-plane. J c decrease by Pr is five times as large as the volume fraction of Pr in the Y-site of the perovskite structure. On the other hand, T c does not show large degradation in YBCO including 10% PrBCO. These results suggest that PrBCO unit cells are fully dispersed in YBa2Cu3O7‑y matrix. With regard to J c in the magnetic field, (Y0.98, Pr0.02)BCO has been slightly improved compared with pure YBCO only in the region of high temperature and low magnetic field of less than 1 T.

Temperature dependence of the ultraviolet luminescence of Pr3+-doped 20Al(PO3)3-80LiF glass scintillator

International Nuclear Information System (INIS)

Tsuboi, Mizuki; Takeda, Kohei; Nakazato, Tomoharu

2017-01-01

The development of scintillator materials for scattered neutrons is essential in studying laser fusion experiments. We have previously investigated and proposed Pr 3+ -doped 20Al(PO 3 ) 3 -80LiF (APLF + Pr) glasses as scintillators for neutron detection. The APLF + Pr glass emissions are then investigated with synchrotron radiation excitation and varying sample temperature. APLF + Pr glasses exhibit luminescence emission located at 200 to 300 nm and 400 nm attributed to the 4f5d → 4f 2 and 4f 2 → 4f 2 ( 1 S 0 → 3 P j + 1 I 6 ) transitions, respectively. In addition, the 200 to 300-nm emission is not substantially affected by temperature, while the 400-nm emission intensities increase with decreasing sample temperature. This temperature dependence is attributed to cross relaxation whose effect can be controlled by the Pr-doping concentration. Our results suggest that doping concentration of APLF + Pr must be optimized and that APLF + Pr glasses must operate a low temperatures for better neutron detection. (author)

Nitrate-assisted photocatalytic efficiency of defective Eu-doped Pr(OH)3 nanostructures.

Science.gov (United States)

Aškrabić, S; Araújo, V D; Passacantando, M; Bernardi, M I B; Tomić, N; Dojčinović, B; Manojlović, D; Čalija, B; Miletić, M; Dohčević-Mitrović, Z D

2017-12-06

Pr(OH) 3 one-dimensional nanostructures are a less studied member of lanthanide hydroxide nanostructures, which recently demonstrated an excellent adsorption capacity for organic pollutant removal from wastewater. In this study, Pr 1-x Eu x (OH) 3 (x = 0, 0.01, 0.03, and 0.05) defective nanostructures were synthesized by a facile and scalable microwave-assisted hydrothermal method using KOH as an alkaline metal precursor. The phase and surface composition, morphology, vibrational, electronic and optical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, infrared (IR), photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). It was deduced that the incorporation of Eu 3+ ions promoted the formation of oxygen vacancies in the already defective Pr(OH) 3 , subsequently changing the Pr(OH) 3 nanorod morphology. The presence of KNO 3 phase was registered in the Eu-doped samples. The oxygen-deficient Eu-doped Pr(OH) 3 nanostructures displayed an improved photocatalytic activity in the removal of reactive orange (RO16) dye under UV-vis light irradiation. An enhanced photocatalytic activity of the Eu-doped Pr(OH) 3 nanostructures was caused by the synergetic effect of oxygen vacancies and Eu 3+ (NO 3 - ) ions present on the Pr(OH) 3 surface, the charge separation efficiency and the formation of the reactive radicals. In addition, the 3% Eu-doped sample exhibited very good adsorptive properties due to different morphology and higher electrostatic attraction with the anionic dye. Pr 1-x Eu x (OH) 3 nanostructures with the possibility of tuning their adsorption/photocatalytic properties present a great potential for wastewater treatment.

Magnetic, thermodynamic and transport properties of novel non-centrosymmetric RCoSi{sub 3} (R=Pr, Nd and Sm) compounds

Energy Technology Data Exchange (ETDEWEB)

Nallamuthu, S. [Department of Physics, National Institute of Technology, Tiruchirappalli 620015, Tamil Nadu (India); Chandrasekaran, S. Selva; Murugan, P. [CSIR-Central Electrochemical Research Institute, Karaikudi 630006, Tamil Nadu (India); Reiffers, Marian [Faculty of Humanities and Natural Sciences, Presov University, Presov (Slovakia); Nagalakshmi, R., E-mail: nagaphys@yahoo.com [Department of Physics, National Institute of Technology, Tiruchirappalli 620015, Tamil Nadu (India)

2016-10-15

Novel non-centrosymmetric RCoSi{sub 3} (R = Pr, Nd and Sm) compounds crystallize in tetragonal BaNiSn{sub 3} type structure with space group I4 mm. The bulk magnetic ordering of all the compounds were confirmed from heat capacity data. Magnetization measurements indicate that PrCoSi{sub 3} orders ferromagnetically at 5.9 K, while NdCoSi{sub 3} and SmCoSi{sub 3} order antiferromagnetically at 4 K and 8 K respectively. The magnetic transitions were also manifested by the slope change of temperature dependent resistivity at low temperatures. The energy level schemes created by crystal electric field splitting are determined from Schottky contribution to specific heat. The existence of magnon gap like features at low temperatures are consistent in both heat capacity and resistivity for NdCoSi{sub 3} and SmCoSi{sub 3}. Large magnetoresistance is observed in NdCoSi{sub 3} and SmCoSi{sub 3}. First principles electronic structure calculation based on density functional theory framework have been performed and compared with experimental data. - Highlights: • Magnetic, transport and thermodynamic studies are investigated extensively. • PrCoSi{sub 3} orders T{sub C} = 5.9 K, NdCoSi{sub 3} and SmCoSi{sub 3} order T{sub N}=4 K and 8 K. • Large magnetoresistance is observed in NdCoSi{sub 3} and SmCoSi{sub 3}. • Density of states calculated at the Fermi levels [N(E{sub F})].

Half metallic ferromagnet Pr_0_._9_5Mn_0_._9_3_9O_3 for spin based devices

International Nuclear Information System (INIS)

Santhosh Kumar, B.; Praveen Shankar, N.; Venkateswaran, C.; Manimuthu, P.

2016-01-01

Half Metallic Ferromagnets (HMF) are excellent candidates for spintronics devices due to their unusual 3d and 4s bands. Band theory and first principles calculations strongly predict that Pr based compounds are promising HMF candidates due to their spin hybridisation. Among all Pr based HMF, Pr_0_._9_5Mn_0_._9_3_9O_3 is special because of its pervoskite structure. The different oxidation states of Mn and Pr will enhance the hybridisation of 3d and 4f bands. The present study is experimental effort on the preparation of Pr based compounds

LiNbO3 :Pr3+ : A Multipiezo Material with Simultaneous Piezoelectricity and Sensitive Piezoluminescence.

Science.gov (United States)

Tu, Dong; Xu, Chao-Nan; Yoshida, Akihito; Fujihala, Masayoshi; Hirotsu, Jou; Zheng, Xu-Guang

2017-06-01

Red-emitting piezoluminescence (elasticoluminescence) is achieved by doping rare earth Pr 3+ into the well-known piezoelectric matrix, LiNbO 3 . By precisely tuning the Li/Nb ratio in nonstoichiometric Li x NbO 3 :Pr 3+ , a material that exhibits an unusually high piezoluminescence intensity, which far exceeds that of any well-known piezoelectric material, is produced. Li x NbO 3 :Pr 3+ shows excellent strain sensitivity at the lowest strain level, with no threshold for stress sensing. These multipiezo properties of sensitive piezoluminescence in a piezoelectric matrix are ideal for microstress sensing, damage diagnosis, electro-mechano-optical energy conversion, and multifunctional control in optoelectronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luminescence and energy transfer of Ce{sup 3+} and Pr{sup 3+} in LaBSiO{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Zhou, Lei; Zhou, Weijie; Shi, Rui; Liu, Chunmeng [MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Huang, Yan; Tao, Ye [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China); Liang, Hongbin, E-mail: cesbin@mail.sysu.edu.cn [MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

2016-09-15

Ce{sup 3+}, Pr{sup 3+} singly doped and Ce{sup 3+}–Pr{sup 3+} doubly doped LaBSiO{sub 5} phosphors were prepared by a high-temperature solid state reaction route. The synchrotron radiation VUV–UV excitation spectra of Ce{sup 3+} and Pr{sup 3+} were measured and the luminescence properties were discussed. The band gap of host compound LaBSiO{sub 5} was estimated from the VUV excitation spectrum of sample activated with Gd{sup 3+}. Furthermore, the influence of temperature on luminescence of Ce{sup 3+} was discussed and the activation energy for thermal quenching was evaluated. The occurrence of energy transfer from excited 5d states of Pr{sup 3+} to Ce{sup 3+} was confirmed by the emission spectra of co-doped samples La{sub 0.99−x}Pr{sub x}Ce{sub 0.01}BSiO{sub 5} and La{sub 0.995−x}Pr{sub 0.005}Ce{sub x}BSiO{sub 5} with different x values.

Electronic structures of PrBa2Cu3O7 and PrBa2Cu4O8 systems based on LSDA+U approach

International Nuclear Information System (INIS)

Shirazi, M.; Tavana, A.; Akhavan, M.

2007-01-01

Full text: The electronic structures of PrBa 2 Cu 3 O 7 (Pr123) and PrBa 2 Cu 4 O 8 (Pr124) have been obtained by means of the density functional theory in the local spin density approximation plus on-site Coulomb interaction. The correlation correction has been applied to the Cu 3d and Pr 4f states. Calculations show that the localized Pr-O bands form near the Fermi surface and do not cross the Fermi level. Comparison of the hole absorbing ability of pfy and the pdy states shows that pfy state has dominant role in grabbing holes from the system and causes Pr124 to be non-superconducting like Pr123. We suggest that hybridization of Pr and O atoms in Pr124 system is weaker than Pr123 compound and this may be the reason for the higher critical doping of Pr by which the superconductivity is completely suppressed. Displacement of the conduction bands at the Fermi level is the criterion of Cu (3dx2-y2) character, and when Cu (3dx2-y2) character is stronger in a band, the band displaces more intensively under applying the correction Ucu. We estimate the hole-concentration from this displacement, and good agreement with experiment is seen. The displacement of the CuO 2 plane bands in the minority and majority spin channels in Pr124 is less than that in Pr123. Displacement of the double chain bands in Pr124 is higher than the single chain bands in Pr123. This feature is related to a stronger Cu (3dx2-y2) character in the double chain. So, the spin and conduction features of the Pr124 double chains are stronger than Pr123 single chain, which is the origin of metallic behavior of Pr124 at low temperatures.(authors)

Electronic structures of PrBa2Cu3O7 and PrBa2Cu4O8 systems based on LSDA+U approach

International Nuclear Information System (INIS)

Shirazi, M.; Tavana, A.; Akhavan, M.

2007-01-01

Full text: The electronic structures of PrBa 2 Cu 3 O 7 (Pr123) and PrBa 2 Cu 4 O 8 (Pr124) have been obtained by means of the density functional theory in the local spin density approximation plus on-site Coulomb interaction. The correlation correction has been applied to the Cu 3d and Pr 4f states. Calculations show that the localized Pr-O bands form near the Fermi surface and do not cross the Fermi level. Comparison of the hole absorbing ability of pfy and the pdy states shows that pfy state has dominant role in grabbing holes from the system and causes Pr124 to be non-superconducting like Pr123. We suggest that hybridization of Pr and O atoms in Pr124 system is weaker than Pr123 compound and this may be the reason for the higher critical doping of Pr by which the superconductivity is completely suppressed. Displacement of the conduction bands at the Fermi level is the criterion of Cu (3dx2-y2) character, and when Cu (3dx2-y2) character is stronger in a band, the band displaces more intensively under applying the correction Ucu. We estimate the hole-concentration from this displacement, and good agreement with experiment is seen. The displacement of the CuO 2 plane bands in the minority and majority spin channels in Pr124 is less than that in Pr123. Displacement of the double chain bands in Pr124 is higher than the single chain bands in Pr123. This feature is related to a stronger Cu (3dx2-y2) character in the double chain. So, the spin and conduction features of the Pr124 double chains are stronger than Pr123 single chain, which is the origin of metallic behavior of Pr124 at low temperatures. (authors)

Influence of Li+ charge compensator ion on the energy transfer from Pr3 + to Gd3 + ions in Ca9Mg(PO4)6F2:Gd3 +, Pr3 +, Li+ phosphor

Science.gov (United States)

Tamboli, Sumedha; Dhoble, S. J.

2017-09-01

Phototherapy is a renowned treatment for curing skin diseases since ancient times. Phototherapeutic treatment for psoriasis and many other diseases require narrow band ultra violet-B (NB-UVB) light with peak intensity at 313 nm to be exposed to the affected part of body. In this paper, we report combustion synthesis of NB-UVB - 313 nm emitting Ca9Mg(PO4)6F2 phosphors doped with Gd3 +, Pr3 + and Li+ ions. The phase formation was confirmed by obtaining X-ray diffraction (XRD) pattern and morphology was studied with the Scanning electron microscopy (SEM) images. Photoluminescence (PL) emission spectra show intense narrow band emission at 313 nm under 274 nm excitation wavelengths. Emission intensity was enhanced when Ca9Mg(PO4)6F2 compound is co-doped with Pr3 + ions. Excitation spectra of Ca9Mg(PO4)6F2:Gd3 +, Pr3 + doped samples shows broad excitation in ultra violet C (UVC) region. Diffuse reflectance spectra (DRS), obtained by UV-visible spectrophotometer, measures the absorption properties of the material. By applying Kubelka Munk function on the diffuse reflectance spectra, band gap of the material is determined. PL decay curves were examined which indicates efficient energy transfer between Pr3 + and Gd3 + ions. Charge compensation effect was also studied by co-doping Li+ ion in host. Emission intensity was found to increase with the addition of charge compensator. The prepared phosphor has potential to convert UVC light into NB-UVB. The luminescence intensity of Gd3 + shows remarkable increase when it is sensitized with Pr3 +, and an addition of charge compensator in the form of Li+, show even better results. This phosphor surely has the potential to be used as phototherapy lamp phosphor.

Pré-resfriamento em água de lichia 'B3' mantida em armazenamento refrigerado Hydrocooling of 'B3' lychee fruit maintained in cold storage

Directory of Open Access Journals (Sweden)

Juan Saavedra del Aguila

2009-11-01

Full Text Available Este experimento visou a estudar o efeito de diferentes temperaturas e tempos de pré-resfriamento em água sobre a qualidade de lichias 'B3', após a frigoconservação. Os tratamentos foram: T1 = controle (sem pré-resfriamento; T2 = imersão por cinco minutos em água a 2,5°C; T3 = imersão por 10 minutos em água a 2,5°C; T4 = imersão por 20 minutos em água a 2,5°C; T5 = imersão por sete minutos em água a 6°C; T6 = imersão por 20 minutos em água a 8°C e T7 = imersão por 10 minutos em água a 10°C. Após a aplicação dos respectivos tratamentos, os frutos foram acondicionados em filmes de polietileno de 24µm, selados e posteriormente armazenados a 5°C e 90% UR, por um período de sete dias, seguido por três dias de comercialização simulada a 20°C e 70% UR. O delineamento experimental foi inteiramente ao acaso, com tratamentos fatoriais de 7x3 (tratamentosxtempo. Foram utilizadas quatro repetições por tratamento, sendo cada uma composta por 150g de frutos. Determinaram-se: perda de massa fresca, coloração (L*, a e b, escurecimento (% e podridões (%. De acordo com os resultados, o pré-resfriamento com água reduz a percentagem de escurecimento, o decréscimo da luminosidade (L* e os valores de a. Por outro lado, esse tratamento favorece o surgimento de altos índices de podridão.This project studied the effects of different precooling temperatures and times with water on lychee 'B3' fruit quality cold storage. The treatments were: T1 = control (without precooling; T2 = immersed in water at 2.5°C for five minutes; T3 = immersed in water at 2.5°C for ten minutes; T4 = immersed in water at 2.5°C for 20 minutes; T5 = immersed in water at 6°C for seven minutes; T6 = immersed in water at 8°C for 20 minutes and T7 = immersed in water at 10°C for ten minutes. After treatments application, the fruits were then placed into polyethylene bags of 24µm, sealed, and stored for seven days at 5°C and 90% RH, plus 3 days at 20�

The relationship of structure to superconductivity in the Pr-Ba-Cu-O system

Science.gov (United States)

Minseo, P.

1994-05-01

The relation of structure to lack of superconductivity in Pr-Ba-Cu-O was systematically investigated. First, the phase equilibria of this system was studied to find the processing parameters which maximize the cation-site ordering between Pr and Ba ions. Second, a comparative study between superconducting Nd-Ba-Cu-O and nonsuperconducting Pr-Ba-Cu-O was performed by forming solid-solution Nd-Pr-Ba-Cu-O. The relation between structure and superconductivity in Nd(1-x)Pr(x)Ba2Cu3O(7-delta) is investigated. T sub c decreases monotonically with increasing x and superconductivity disappears at around x = 0.3 to 0.4. T sub c is enhanced by 10 K when the sample is processed at an oxygen partial pressure (PO2) of 0.01 atm, followed by oxygenation at 450 C. Depression of T sub c as a function of x and PO2 is explained in terms of a charge-transfer model. It is suggested that destruction of superconductivity in the RE(1-x)Pr(x)Ba2Cu3O(7-delta) (RE=rare-earth) system can be viewed as disruption of four-fold planar coordinated Cu ions in the chain-site due to permanent occupation of extra Pr ions on Ba sites.

Interplay of charge, orbital and magnetic order in Pr1-xCaxMnO3

International Nuclear Information System (INIS)

Zimmermann V, M.; Hill, J.P.; Gibbs, D.; Blume, M.; Casa, D.; Keimer, B.; Murakami, Y.; Tomioka, Y.; Tokura, Y.

1999-01-01

The authors report resonant x-ray scattering studies of charge and orbital order in Pr 1-x Ca x MnO 3 with x = 0.4 and 0.5. Below the ordering temperature, T O = 245 K, the charge and orbital order intensities follow the same temperature dependence, including an increase at the antiferromagnetic ordering temperature, T N . High resolution measurements reveal, however, that long range orbital order is never achieved. Rather, an orbital domain state is formed. Above T O , the charge order fluctuations are more highly correlated than the orbital fluctuations. Similar phenomenology is observed in a magnetic field. They conclude that the charge order drives the orbital order at the transition

Luminescent properties and quenching effects of Pr3+ co-doping in SiO2:Tb3+/Eu3+ nanophosphors

CSIR Research Space (South Africa)

Mhlongo, GH

2014-02-01

Full Text Available Luminescence properties of Pr(sup3+) single doped SiO2 and Pr(sup3+) co-doped SiO(sub2):Tb(sup3+)/Eu(sup3+) nanophosphors synthesized using sol–gel method were investigated. X-ray diffraction (XRD), and scanning electron microscope (SEM) were used...

Luminescence and light yield of (Gd2Y)(Ga3Al2)O12:Pr3+ single crystal scintillators

Science.gov (United States)

Lertloypanyachai, Prapon; Pathumrangsan, Nichakorn; Sreebunpeng, Krittiya; Pattanaboonmee, Nakarin; Chewpraditkul, Weerapong; Yoshikawa, Akira; Kamada, Kei; Nikl, Martin

2017-06-01

Praseodymium-doped (Gd2Y)(Ga3Al2)O12 (GYGAG: Pr) single crystals are grown by the micro-pulling down method with different Pr concentrations. The energy transfer process between Pr3+ and Gd3+ is investigated by photoluminescence excitation (PLE) and emission (PL) spectra measurements. Photoelectron yield measurements are carried out using photomultiplier. At 662 keV γ-rays, photoelectron yield of 2520 phe/MeV obtained for the GYGAG: Pr (0.01%) sample is larger than that of 1810 phe/MeV obtained for BGO crystal. Light yield degradation for the GYGAG: Pr scintillators is presumably due to the energy transfer from 5d state of Pr3+ to 4f state of Gd3+ together with the concentration quenching in the Gd3+-sublattice.

Magnetic order in PrBa2Cu3O6+x

DEFF Research Database (Denmark)

Longmore, A.; Nutley, M.P.; Boothroyd, A.T.

1994-01-01

We have studied the magnetic ordering of the Cu and Pr ions in PrBa2Cu3O6+x by neutron diffraction on single crystals with different oxygen contents. Two types of Cu ordering were observed, qualitatively similar to the anti-ferromagnetic phases reported in some studies of YBa2Cu3O6+x. A third...... magnetic structure was observed below 15K, which we believe corresponds to the magnetic ordering of the Pr sub-lattice....

Comportamento térmico e acústico de pré-fabricados de madeira

OpenAIRE

Santos, Ana Cristina Figueiredo Mendes dos

2008-01-01

A madeira é um elemento natural que, genericamente, tem um bom comportamento térmico e acústico, cuja produção é sustentável. Por isso, as edificações pré-fabricadas construídas neste material constituem uma mais-valia em termos ambientais e a nível do conforto proporcionado aos seus habitantes. Após uma introdução referente ao enquadramento histórico das casas em madeira, foi efectuada uma comparação relativamente aos regulamentos de térmica antigo e actual, assim como r...

Structural, magnetic and dielectric properties of Pr-modified BiFeO3 multiferroic

International Nuclear Information System (INIS)

Varshney, Dinesh; Sharma, Poorva; Satapathy, S.; Gupta, P.K.

2014-01-01

Graphical abstract: -- Highlights: • BFO and Bi 0.95 Pr 0.05 FeO 3 prepared successfully via solid state reaction route. • XRD confirms rhombohedral structure with space group R3c. • Relaxation process is attributed to thermal motion and hopping of V O 2+ . • Magnetization is enhanced in Bi 0.95 Pr 0.05 FeO 3 sample. • Enhanced magnetization stem from suppression of the spiral spin modulation. -- Abstract: The structural, vibrational, magnetic and dielectric properties of polycrystalline BiFeO 3 and Bi 0.95 Pr 0.05 FeO 3 are investigated by combining X-ray diffraction, Raman scattering spectra, magnetometry and dielectric measurements. Structural symmetry with rhombohedral R3c phase is revealed for both parent and 5% Pr substitution at Bi site, serving no chemical pressure and causes no structural transition from R3c to any other phase is identified from X-ray diffraction patterns and Raman scattering spectra. The shifting of phonon modes towards higher frequency side is attributed to lower atomic mass of Pr ion as compared to Bi ion. The magnetic measurements at room temperature indicate that Pr substitution induces ferromagnetism and discerns large and non-zero remnant magnetization as compare to pristine BiFeO 3 . Both dielectric permittivity and loss factor of Bi 0.95 Pr 0.05 FeO 3 strongly decreases with increased frequency. Significant role of hopping of oxygen ion vacancies in Bi 0.95 Pr 0.05 FeO 3 is inferred from modulus spectra and ac conductivity analysis

Luminescent properties of Pr3+-sensitized LaPO4:Gd3+ ultraviolet-B phosphor under vacuum-ultraviolet light excitation

International Nuclear Information System (INIS)

Okamoto, Shinji; Uchino, Rika; Kobayashi, Keisuke; Yamamoto, Hajime

2009-01-01

Luminescent properties of Pr 3+ -sensitized LaPO 4 :Gd 3+ under vacuum-ultraviolet (vuv) light excitation have been investigated. The energy transfer probably occurs from the 5d levels in Pr 3+ ions to Gd 3+ ions under 172 nm light excitation. LaPO 4 :Gd 3+ ,Pr 3+ shows efficient ultraviolet-B (uv-B) emission at 312 nm, whose peak intensity reaches its maximum at Gd=35 mol % and Pr=5 mol %. (La 0.65 Gd 0.35 ) 0.95 Pr 0.05 PO 4 is about 1.6 times higher than a typical uv-B phosphor for vuv lamp, Y 0.75 Gd 0.25 Al 3 (BO 3 ) 4 , in Gd 3+ -emission intensity under 172 nm light excitation. This result implies that the Pr 3+ -sensitized LaPO 4 :Gd 3+ is a candidate of uv-B phosphors for xenon-excimer discharge vuv lamps. In order to evaluate the effect of the narrow-band uv-B emission by LaPO 4 :Gd 3+ ,Pr 3+ phosphor, irradiation test on DNA was performed. The irradiation damage of pUC 18 DNA by the narrow-band uv-B light from the LaPO 4 :Gd 3+ ,Pr 3+ phosphor is in the same magnitude as that by uv-A light from a filtered Hg lamp, even though the uv-B lamp is higher than the uv-A lamp in power density and photon energy.

Alternativas técnicas para o controle das alterações dimensionais das resinas acrílicas em prótese total

OpenAIRE

GOMEZ Tomas; MORI Matsuyoshi; CORRÊA Gerson de Arruda; MATSON Edmir

1998-01-01

Os autores propõem uma nova técnica para diminuição dos problemas provenientes das alterações dimensionais das resinas acrílicas utilizadas na confecção das próteses totais. Com essa proposta, conseguiu-se praticamente eliminar essas alterações dimensionais tão prejudiciais às próteses totais.

Incommensurate magnetism in PrBa2Cu3O6.92

DEFF Research Database (Denmark)

Hill, J.P.; Boothroyd, A.T.; Andersen, N.H.

1998-01-01

We report resonant x-ray magnetic scattering and high-resolution neutron-diffraction studies of the Pr site magnetism in high quality single crystals of PrBa2Cu3O6.92. These studies reveal that the Pr sublattice orders at 19 K in a well correlated, long period incommensurate structure with probable...

The down-conversion and up-conversion photoluminescence properties of Na0.5Bi0.5TiO3:Yb3+/Pr3+ ceramics

International Nuclear Information System (INIS)

Huang, Yinpeng; Luo, Laihui; Wang, Jia; Zuo, Qianghui; Yao, Yongjie; Li, Weiping

2015-01-01

Na 0.5 Bi 0.5−x−y Yb x Pr y TiO 3 (NBT:xYb/yPr) ceramics with different Yb and Pr contents are prepared. Both the down-conversion (DC) and up-conversion (UC) photoluminescence (PL) of the ceramics via 453 and 980 nm excitation, respectively, are investigated. The effect of Yb 3+ and Pr 3+ doping contents on the DC and UC PL is significantly different from each other. Furthermore, the UC PL of the ceramics as a function of temperatures is measured to investigate the UC process in detail. Based on energy level diagram of Pr 3+ and Yb 3+ ions and the DC and UC PL spectra, the DC and UC PL mechanisms of Pr 3+ and Yb 3+ ions are discussed. Especially, the UC PL mechanism is clarified, which is different from the previously reported literature. Also, the temperature sensing properties of the ceramics are studied based on the photoluminescence ratio technique, using the thermal coupling energy levels of Pr 3+

Moessbauer studies of single crystal Pr sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3

CERN Document Server

Uhm, Y R; Kim, C S; Tomioka, Y; Tokura, Y

2000-01-01

Single crystal Pr sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3 was synthesized by using the floating zone method and the relation of magnetic properties and charge ordering transition with lattice dynamics was systematically investigated. Moessbauer spectra of Pr sub 1 sub / sub 3 sub S r sub 2 sub / sub 3 FeO sub 3 were taken at various temperatures ranging from 20 K to room temperature. The charge disproportionation, in which iron with valence states Fe sup 3 sup + and Fe sup 5 sup + was found in a ratio of 2:1, was detected in Pr sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3 below 190+-3 K. Iron with valence state Fe sup 4 sup + coexisted in Pr sub 1 sub / sub 3 sub S r sub 2 sub / sub 3 FeO sub 3 at and above 150 K, and its ratio increased from 13 to 66 % with increasing temperature. This result means that charge-ordered and -disordered phases co-exist in Pr sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3.

Thermoluminescent response of LaAlO{sub 3}:Pr; Respuesta termoluminiscente de LaAlO{sub 3}:Pr

Energy Technology Data Exchange (ETDEWEB)

Morales H, A.; Zarate M, J. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Edif. U, 58060 Morelia, Michoacan (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Rivera M, T., E-mail: feyo_yo@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico)

2015-10-15

In this study, the thermoluminescence response of doped lanthanum aluminate (LaAlO{sub 3}) with praseodymium ion (Pr) obtained by the Pechini method and drying by the spraying technique Spry Dryer was studied. The obtained powders were analyzed structurally by the X-ray diffraction technique; the morphological characterization was by the scanning electron microscopy technique. The obtained powders at 800 degrees C presented crystallinity and showed a Rhombohedral crystal structure, this phase was observed by X-ray diffraction patterns. Thermoluminescence response of LaAlO{sub 3}:Pr showed a brightness curve with a peak centered at 157 degrees C. The sensitivity of the doped samples was improved about 90 times in comparison with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 230 nm, reproducibility of thermoluminescence response was ±50%. Also the fading in thermoluminescence response was studied. (Author)

Polo-like kinase 3 (PLK3) mediates the clearance of the accumulated PrP mutants transiently expressed in cultured cells and pathogenic PrP(Sc) in prion infected cell line via protein interaction.

Science.gov (United States)

Wang, Hui; Tian, Chan; Fan, Xue-Yu; Chen, Li-Na; Lv, Yan; Sun, Jing; Zhao, Yang-Jing; Zhang, Lu-bin; Wang, Jing; Shi, Qi; Gao, Chen; Chen, Cao; Shao, Qi-Xiang; Dong, Xiao-Ping

2015-05-01

Polo-like kinases (PLKs) family has long been known to be critical for cell cycle and recent studies have pointed to new dimensions of PLKs function in the nervous system. Our previous study has verified that the levels of PLK3 in the brain are severely downregulated in prion-related diseases. However, the associations of PLKs with prion protein remain unclear. In the present study, we confirmed that PrP protein constitutively interacts with PLK3 as determined by both in vitro and in vivo assays. Both the kinase domain and polo-box domain of PLK3 were proved to bind PrP proteins expressed in mammalian cell lines. Overexpression of PLK3 did not affect the level of wild-type PrP, but significantly decreased the levels of the mutated PrPs in cultured cells. The kinase domain appeared to be responsible for the clearance of abnormally aggregated PrPs, but this function seemed to be independent of its kinase activity. RNA-mediated knockdown of PLK3 obviously aggravated the accumulation of cytosolic PrPs. Moreover, PLK3 overexpression in a scrapie infected cell line caused notable reduce of PrP(Sc) level in a dose-dependent manner, but had minimal effect on the expression of PrP(C) in its normal partner cell line. Our findings here confirmed the molecular interaction between PLK3 and PrP and outlined the regulatory activity of PLK3 on the degradation of abnormal PrPs, even its pathogenic isoform PrP(Sc). We, therefore, assume that the recovery of PLK3 in the early stage of prion infection may be helpful to prevent the toxic accumulation of PrP(Sc) in the brain tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

An NMR study of Pr0.5Ca0.5Mn1-xGaxO3 (x = 0 and 0.03)

International Nuclear Information System (INIS)

Oates, C.J.; Sikora, M.; Zajac, D.; Rybicki, D.; Kapusta, Cz.; Riedi, P.C.; Martin, C.; Yaicle, M.; Maignan, A.

2004-01-01

An NMR study of polycrystalline Pr 0. 5Ca 0.5 Mn 1-x Ga x O 3 (x = 0 and 0.03) at 3 K is presented. Zero field spin echo spectra of the Ga doped compound consist of an overlapping 6: 9 ,71 Ga signal at 74 MHz (hyperfine field of 5.3 T), a 55 Mn double exchange line at 375 MHz (35.5 T) and a weak Mn 3+ signal between 400 and 550 MHz. Measurements in an applied field show a step-like increase in the double exchange line intensity, which corresponds to an increase in the amount of the ferromagnetic metallic phase. This coincides with a step-like feature in the bulk magnetization measurements. The effect is similar to that in the previous field dependent 55 Mn NMR measurements of Pr 0.67 Ca 0.33 MnO 3 . At the demagnetized and remanent state, a variation of spin-spin relaxation time T 2 , across the 55 Mn line, due to a Suhl-Nakamura interaction is observed, which suggests that the ferromagnetic metallic double exchange regions, at liquid helium temperatures, are at least 4 nm in size

Spin-spin cross relaxation and spin-Hamiltonian spectroscopy by optical pumping of Pr/sup 3+/:LaF3

International Nuclear Information System (INIS)

Lukac, M.; Otto, F.W.; Hahn, E.L.

1989-01-01

We report the observation of an anticrossing in solid-state laser spectroscopy produced by cross relaxation. Spin-spin cross relaxation between the /sup 141/Pr- and /sup 19/F-spin reservoirs in Pr/sup 3+/:LaF 3 and its influence on the /sup 141/Pr NMR spectrum is detected by means of optical pumping. The technique employed combines optical pumping and hole burning with either external magnetic field sweep or rf resonance saturation in order to produce slow transient changes in resonant laser transmission. At a certain value of the external Zeeman field, where the energy-level splittings of Pr and F spins match, a level repulsion and discontinuity of the Pr/sup 3+/ NMR lines is observed. This effect is interpreted as the ''anticrossing'' of the combined Pr-F spin-spin reservoir energy states. The Zeeman-quadrupole-Hamiltonian spectrum of the hyperfine optical ground states of Pr/sup 3+/:LaF 3 is mapped out over a wide range of Zeeman magnetic fields. A new scheme is proposed for dynamic polarization of nuclei by means of optical pumping, based on resonant cross relaxation between rare spins and spin reservoirs

Magnetic and thermodynamic properties of the Pr-based ferromagnet PrGe2-δ

Science.gov (United States)

Matsumoto, Keisuke T.; Morioka, Naoya; Hiraoka, Koichi

2018-03-01

We investigated the magnetization, M, and specific heat, C, of ThSi2-type PrGe2-δ. A polycrystalline sample of PrGe2-δ was prepared by arc-melting. Magnetization divided by magnetic field, M / B, increased sharply and C showed a clear jump at the Curie temperature, TC, of 14.6 K; these results indicate that PrGe2-δ ordered ferromagnetically. The magnetic entropy at TC reached R ln 3, indicating a quasi-triplet crystalline electric field (CEF) ground state. The maximum value of magnetic entropy change was 11.5 J/K kg with a field change of 7 T, which is comparable to those of other right rare-earth based magnetocaloric materials. This large magnetic entropy change was attributed to the quasi-triplet ground state of the CEF.

Visible-to-UVC upconversion efficiency and mechanisms of Lu{sub 7}O{sub 6}F{sub 9}:Pr{sup 3+} and Y{sub 2}SiO{sub 5}:Pr{sup 3+} ceramics

Energy Technology Data Exchange (ETDEWEB)

Cates, Ezra L. [Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC 29625 (United States); Center for Optical Materials Science and Engineering Technologies, Clemson University, Anderson, SC 29625 (United States); Wilkinson, Angus P. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Kim, Jae-Hong, E-mail: jaehong.kim@yale.edu [Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511 (United States)

2015-04-15

Visible-to-UVC upconversion (UC) by Pr{sup 3+}-doped materials is a promising candidate for application to sustainable disinfection technologies, including light-activated antimicrobial surfaces and solar water treatment. In this work, we studied Pr{sup 3+} upconversion in an oxyfluoride host system for the first time, employing Lu{sub 7}O{sub 6}F{sub 9}:Pr{sup 3+} ceramics. Compared to the previously studied Y{sub 2}SiO{sub 5}:Pr{sup 3+} reference material, the oxyfluoride host resulted in a 5-fold increase in intermediate state lifetime, likely due to a lower maximum phonon energy; however, only a 60% gain in UC intensity was observed. To explain this discrepancy, luminescence spectral distribution and decay kinetics were studied in both phosphor systems. The Pr{sup 3+} 4f5d band energy distribution in each phosphor was found to play a key role by allowing or disallowing the occurrence of a previously unexplored UC mechanism, which had a significant impact on overall efficiency. - Highlights: • Visible-to-UVC upconversion by Pr{sup 3+} was studied in an oxyfluoride host matrix for the first time. • Lu{sub 7}O{sub 6}F{sub 9}:Pr{sup 3+} ceramics were synthesized and characterized. • Lu{sub 7}O{sub 6}F{sub 9}:Pr{sup 3+} shows more intense UV upconversion than Y{sub 2}SiO{sub 5}:Pr{sup 3+}, with differing mechanisms. • 4f5d band energy and {sup 1}D{sub 2} involvement are important in maximizing upconversion efficiency.

Mechanically alloyed PrFeB nanocrystalline magnets

International Nuclear Information System (INIS)

Kaszuwara, W.; Leonowicz, M.

1998-01-01

Mechanically alloyed PrFeB nanocrystalline magnets were prepared by extensive ball milling of Pr, Fe and Fe 80 B 20 powders, followed by diffusion annealing. After milling, the material consisted of nanocrystalline α-Fe crystallites embedded in amorphous Pr-rich matrix. Thermomagnetic and calorimetric investigations of the transformations which occurred during annealing showed that the amorphous phase crystallised at 240 C, leading to the formation of crystalline Pr having lattice constants 10% greater than those shown in the ASTM data. This fact indicated that mechanical alloying and low temperature annealing led to the formation of a solid solution of either Fe or B in Pr, which does not exist in the equilibrium state. The Pr 2 Fe 14 B phase was subsequently formed within a temperature range of 420-620 C. The magnetic properties of magnets depend on the phase structure and grain size. Milling time appears to be a decisive processing parameter for the tailoring of the magnetic properties. Depending on the phase structure, the coercivities varied from 100 to 1200 kA/m and, respectively, the remanences from 0.98 T to 0.6 T. The highest maximum energy product was 80 kJ/m 3 . (orig.)

Anomalous properties of PrBa2Cu3O7: a comment

International Nuclear Information System (INIS)

Sampathkumaran, E.V.

1992-01-01

Considerable attention has been paid in the literature to understand the suppression of superconductivity and the large Neel temperature of the Pr sub-lattice in PrBa 2 Cu 3 O 7 . Here we briefly recall the superconducting and magnetic anomalies noted earlier in other Pr based systems due to the partial delocalisation of the Pr-4f orbital to show that the gross anomalous features observed for PrBa 2 Cu 4 O 7 are not unique. (orig.)

Magnetic and thermoelectric properties of electron doped Ca{sub 0.85}Pr{sub 0.15}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Hossain Khan, Momin [Department of Physics, University of Kalyani, Kalyani 741235, West Bengal (India); Pal, Sudipta, E-mail: sudipta.pal@rediffmail.com [Department of Physics, University of Kalyani, Kalyani 741235, West Bengal (India); Bose, Esa [Department of Engineering Physics, B. P. P. I. M.T, Kolkata 700052, West Bengal (India)

2015-10-01

We have investigated temperature-dependent magnetization (M), magnetic susceptibility (χ) and thermoelectric (S) properties of the electron-doped Ca{sub 0.85}Pr{sub 0.15}MnO{sub 3}. With decrease of temperature, paramagnetic (PM) to antiferromagnetic (AFM) phase transition occurs with a well-defined Néel temperature (T{sub N}=122 K). Magnetic susceptibility measurements reveal that the paramagnetic state involves modified Curie–Weiss paramagnetism. Field cooled and zero field cooled magnetization measurements indicate a signature of magnetic frustration. Ferromagnetic (FM) double-exchange interactions associated with doped e{sub g} electrons are favored over competing AFM interactions below T{sub irr}=112 K. Magnetization data also shows a second-order phase transition. The sign reversal in S(T) has been interpreted in terms of the change in the electronic structure relating to the orbital degrees of freedom of the doped e{sub g} electron. Low temperature (5–140 K) thermoelectric power, S (T) signifies the importance of electron–magnon scattering process. - Highlights: • Magnetic and thermoelectric properties have been investigated in Ca{sub 0.85}Pr{sub 0.15}MnO{sub 3}. • It shows a PM–AFM second order phase transition at T{sub N}=122 K. • PM state involves modified Curie–Weiss paramagnetism. • The electron–magnon scattering dominates temperature dependent thermoelectric power.

S1PR3 Signaling Drives Bacterial Killing and Is Required for Survival in Bacterial Sepsis.

Science.gov (United States)

Hou, JinChao; Chen, QiXing; Wu, XiaoLiang; Zhao, DongYan; Reuveni, Hadas; Licht, Tamar; Xu, MengLong; Hu, Hu; Hoeft, Andreas; Ben-Sasson, Shmuel A; Shu, Qiang; Fang, XiangMing

2017-12-15

Efficient elimination of pathogenic bacteria is a critical determinant in the outcome of sepsis. Sphingosine-1-phosphate receptor 3 (S1PR3) mediates multiple aspects of the inflammatory response during sepsis, but whether S1PR3 signaling is necessary for eliminating the invading pathogens remains unknown. To investigate the role of S1PR3 in antibacterial immunity during sepsis. Loss- and gain-of-function experiments were performed using cell and murine models. S1PR3 levels were determined in patients with sepsis and healthy volunteers. S1PR3 protein levels were up-regulated in macrophages upon bacterial stimulation. S1pr3 -/- mice showed increased mortality and increased bacterial burden in multiple models of sepsis. The transfer of wild-type bone marrow-derived macrophages rescued S1pr3 -/- mice from lethal sepsis. S1PR3-overexpressing macrophages further ameliorated the mortality rate of sepsis. Loss of S1PR3 led to markedly decreased bacterial killing in macrophages. Enhancing endogenous S1PR3 activity using a peptide agonist potentiated the macrophage bactericidal function and improved survival rates in multiple models of sepsis. Mechanically, the reactive oxygen species levels were decreased and phagosome maturation was delayed in S1pr3 -/- macrophages due to impaired recruitment of vacuolar protein-sorting 34 to the phagosomes. In addition, S1RP3 expression levels were elevated in monocytes from patients with sepsis. Higher levels of monocytic S1PR3 were associated with efficient intracellular bactericidal activity, better immune status, and preferable outcomes. S1PR3 signaling drives bacterial killing and is essential for survival in bacterial sepsis. Interventions targeting S1PR3 signaling could have translational implications for manipulating the innate immune response to combat pathogens.

Jurnalistikadan gələn PR-çı

OpenAIRE

Mənsimi, Cəfər; Soltan, Arzu (editör)

2017-01-01

Azerbaycan'da ilk online PR derggisi olan PRoloq.az'da PR uzmanı ve "PR labarotoriya"nın başkanı Afet Yaqubova ile röportaj. PR mütəxəssisi və PR laboratoriyanın direktoru Afət Yaqubova ilə müsahibə,

Comparing the physical properties of Pr/Gd and Pr/Ce substitutions in Ru(Gd1.5Ce0.5)Sr2Cu2O10- δ

Science.gov (United States)

Khajehnezhad, A.; Nikseresht, N.; Hadipour, H.; Akhavan, M.

2008-06-01

We have compared the electrical and magnetic properties of Ru(Gd1.5- x Pr x )Ce0.5Sr2Cu2O10- δ (Pr/Gd samples) with x = 0.0, 0.01, 0.03, 0.033, 0.035, 0.04, 0.05, 0.06, 0.1 and RuGd1.5(Ce0.5- x Pr x ) Sr2 Cu2O10- δ (Pr/Ce samples) with x = 0.0, 0.01, 0.03, 0.05, 0.08, 0.1, 0.15, 0.2 prepared by the standard solid-state reaction technique. We obtained the XRD patterns for different samples with various x. The lattice parameters versus x for different substitutions have been obtained from Rietveld analysis. To determine how the magnetic and superconducting properties of these layered cuprate systems can be affected by Pr substitution, the resistivity, and magnetoresistivity, with H ext varying from 0.0 to 15 kOe, have been measured at various temperatures. Superconducting transition temperature T c and magnetic transition T irr , have been obtained through resistivity and ac susceptibility measurements. The T c suppression due to Pr/Gd and Pr/Ce substitutions show competition between pair breaking by magnetic impurities, hole doping due to different valances of ions, difference in ionic radii, and oxygen stoichiometry. Pr/Gd substitution suppresses superconductivity more rapidly than for Pr/Ce, showing that the effect of hole doping and magnetic impurity pair breaking is stronger than the difference in ionic radii. In Pr/Gd substitution, the small difference between the ionic radii of Pr3+,4+ and Gd3+, and absorption of more oxygen due to the higher valence of Pr with respect to Gd, decreases the mean Ru-Ru distance, and as a result, the magnetic exchange interaction becomes stronger with the increase of x. However, Pr/Ce substitution has the opposite effect. The magnetic parameters such as H c , obtained through magnetization measurements versus applied magnetic field isotherm at 77 K and room temperatures, become stronger with x in Pr/Gd and weaker with x in Pr/Ce substitution.

Apparent molar volumes and apparent molar heat capacities of Pr(NO3)3(aq), Gd(NO3)3(aq), Ho(NO3)3(aq), and Y(NO3)3(aq) at T (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa

International Nuclear Information System (INIS)

Hakin, Andrew W.; Liu Jinlian; Erickson, Kristy; Munoz, Julie-Vanessa; Rard, Joseph A.

2005-01-01

Relative densities and relative massic heat capacities have been measured for acidified solutions of Y(NO 3 ) 3 (aq), Pr(NO 3 ) 3 (aq), and Gd(NO 3 ) 3 (aq) at T = (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa. In addition, relative densities and massic heat capacities have been measured at the same temperatures and pressure for Y(NO 3 ) 3 (aq) and Ho(NO 3 ) 3 (aq) solutions without excess acid (n.b. measurements at T = 328.15 K for Ho(NO 3 ) 3 (aq) were not performed due to the limited volume of solution available). Apparent molar volumes and apparent molar heat capacities for the aqueous salt solutions have been calculated from the experimental apparent molar properties of the acidified solutions using Young's rule, whereas the apparent molar properties of the solutions without excess acid were calculated directly from the measured densities and massic heat capacities. The two sets of data for the Y(NO 3 ) 3 (aq) systems provide a check of the internal consistency of the Young's rule approach we have utilised. The concentration dependences of the apparent molar volumes and heat capacities of the aqueous salt solutions have been modelled at each investigated temperature using the Pitzer ion interaction equations to yield apparent molar properties at infinite dilution. Complex formation within the aqueous rare earth nitrate systems is discussed qualitatively by probing the concentration dependence of apparent molar volumes and heat capacities. In spite of the complex formation in the aqueous rare earth nitrate systems, there is a high degree of self-consistency between the apparent molar volumes and heat capacities at infinite dilution reported in this manuscript and those previously reported for aqueous rare earth perchlorates

Prügiveo hind hakkab olenema inimesest endast / Peep Aaviksoo ; interv. Jaan Rõõmussaar

Index Scriptorium Estoniae

Aaviksoo, Peep, 1956-

2004-01-01

Ilmunud ka: Stolitsa, 5. nov. 2004, lk. 3. AS-i Tallinna Prügila taotles prügi ladestamishinna tõstmist, ettevõtlusameti hinna ja tarbijakaitse osakond pidas taotletavat hinda liiga kõrgeks. Tallinna abilinnapea vastab küsimustele prügimajanduse kota

PR-teenuse hind tõuseb 20% / Eda-Liis Kann

Index Scriptorium Estoniae

Kann, Eda-Liis, 1979-

2004-01-01

Suhtekorraldusfirmad prognoosivad aasta teiseks pooleks PR-teenuste 20protsendilist hinnatõusu. Kommenteerivad Kersti Luha, Maren Pärn, Ingrid Eha, Maria Raudsepp, Heidi Pihlak ja Rein Meripõld. Lisa: Väikefirmale on PR-teenus kallis

Obese gene expression at in vivo levels by fat pads derived from s.c. implanted 3T3-F442A preadipocytes

DEFF Research Database (Denmark)

Mandrup, S; Loftus, T M; MacDougald, O A

1997-01-01

3T3-F442A preadipocytes implanted s.c. into athymic mice develop into fat pads that are indistinguishable from normal adipose tissue. Implanted preadipocytes harboring a beta-galactosidase transgene gave rise to fat pads in which almost all adipocytes expressed beta-galactosidase. This finding pr...

Effect of hydrostatic pressure on magnetic and magnetocaloric properties in La{sub 0.35}Pr{sub 0.35}Ca{sub 0.3}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Thiyagarajan, R. [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu (India); Esakki Muthu, S. [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu (India); Univ. Grenoble Alpes and CEA, INAC-SPSMS, F-38000 Grenoble (France); Manikandan, K. [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu (India); Arumugam, S., E-mail: sarumugam1963@yahoo.com [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu (India)

2016-01-15

Magnetization of polycrystalline La{sub 0.35}Pr{sub 0.35}Ca{sub 0.3}MnO{sub 3} sample has been measured as a function of temperature (T) and magnetic field (H) under various external hydrostatic pressures (P) up to ~1 GPa. At ambient P, the sample exhibits paramagnetic (PM)–ferromagnetic (FM) transition (T{sub C}) at 167 K and 173 K in cooling and warming cycles respectively under the magnetic field (µ{sub 0}.H) of 0.1 T. It also shows a hysteresis during both temperature- and field- dependence of magnetization measurements at ambient P, suggests the presence of a first-order transition. Moreover, the field dependence of magnetization shows S type field-induced metamagnetic transition (FIMMT) over a temperature range below T{sub C} in the FM state. The application of P in M(T) increases T{sub C} at a rate [dT{sub C}/dP] of 13.9 K/GPa, but the thermally-driven first-order transition is not affected by P. However, the applied P suppresses FIMMT and reduces field-driven first-order transition in the magnetization isotherms [M(H)]below T{sub C}. H increases both magnetic entropy change (∆S{sub m}) and Relative Cooling Power (RCP), whereas the P slightly increases ∆S{sub m}{sup max} and no appreciable change in RCP. These results suggest that H and P can be used as a tool to enhance magnetocaloric values in the phase separated manganites. - Highlights: • At ambient P, La{sub 0.35}Pr{sub 0.35}Ca{sub 0.3}MnO{sub 3} sample shows first-order PM–FM transition. • P increases the T{sub C} at a rate of 13.9 K/GPa, thermal hysteresis is not affected. • P diminishes the field-driven first-order PM–FM transition, suppresses FIMMMT. • H increases ∆S{sub m} and RCP. P slightly increases ∆S{sub m}{sup max}, but no change in RCP by P.

Valence determination as a function of doping in $PrBa_{2} Cu_{3} O_{7}$

CERN Document Server

Staub, U; Wasserman, S R; Conner, A G O; Kramer, M J; Patterson, B D; Shi, M; Knapp, M P

2000-01-01

We present results of X-ray absorption near edge spectra (XANES), neutron powder diffraction, and resonant X-ray diffraction on samples of PrBa/sub 2/Cu/sub 3/O/sub 7- delta / and Pr/sub 1-x/Ca/sub x/Ba /sub 2/Cu/sub 3/O/sub 7/. The data are obtained as a function of the doping levels of oxygen and Ca. There are significant changes in the Pr L/sub 3/ XANES spectra with changes in oxygen or Ca concentrations, indicating that the Pr electronic properties are affected by doping. The resonant X-ray scattering experiments show that the changes observed occur on Pr ions incorporated in the PrBa /sub 2/Cu/sub 3/O/sub 7- delta / structure, and are not the result of changes to a Pr-containing impurity phase. A quantitative model, based on literature precedent, is used to extract Pr valences from the data, although the XANES cannot distinguish between models involving charge transfer and those involving hybridization. The results are compared with data obtained from Pb/sub 2/Sr/sub 2/Pr/sub 1-x/Ca/sub x/Cu/sub 3/O/sub ...

Toxicity of laser irradiated photoactive fluoride PrF3 nanoparticles toward bacteria

International Nuclear Information System (INIS)

Pudovkin, M S; Korableva, S L; Krasheninnicova, A O; Nizamutdinov, A S; Semashko, V V; Zelenihin, P V; Alakshin, E M; Nevzorova, T A

2014-01-01

The article is devoted to exploration of biological effects of crystalline PrF 3 nanoparticles toward Salmonella typhimurium TA 98 bacteria under the laser irradiation. Obtained results show bactericidal activity of PrF 3 nanoparticles and optimal parameters of laser irradiation (power of laser irradiation, wavelength, diameter of the laser spoil, and exposure time) have been found under which the effects of bactericidal activity become the most significant. Survival of bacterial cells under laser irradiation with wavelength 532 nm in colloidal solution of PrF 3 nanoparticles was 39%, 34%, 20% for exposure times 5 minutes, 15 minutes and 30 minutes, correspondingly

Spin-state crossover and low-temperature magnetic state in yttrium-doped Pr0.7Ca0.3CoO3

Science.gov (United States)

Knížek, K.; Hejtmánek, J.; Maryško, M.; Novák, P.; Šantavá, E.; Jirák, Z.; Naito, T.; Fujishiro, H.; de la Cruz, Clarina

2013-12-01

The structural and magnetic properties of two mixed-valence cobaltites with a formal population of 0.30 Co4+ ions per f.u., (Pr1-yYy)0.7Ca0.3CoO3 (y=0 and 0.15), have been studied down to very low temperatures by means of high-resolution neutron diffraction, SQUID magnetometry, and heat-capacity measurements. The results are interpreted within the scenario of the spin-state crossover from a room-temperature mixture of the intermediate-spin Co3+ and low-spin Co4+ (IS/LS) to the LS/LS mixture in the sample ground states. In contrast to the yttrium-free y=0 that retains the metallic-like character and exhibits ferromagnetic (FM) ordering below 55 K, the doped system y=0.15 undergoes a first-order metal-insulator transition at 132 K, during which not only the crossover to low-spin states but also a partial electron transfer from Pr3+ 4f to cobalt 3d states takes place simultaneously. Taking into account the nonmagnetic character of LS Co3+, such a valence shift electronic transition causes a magnetic dilution, formally to 0.12 LS Co4+ or 0.12 t2g hole spins per f.u., which is the reason for an insulating, highly nonuniform magnetic ground state without long-range order. Nevertheless, even in that case there exists a relatively strong molecular field distributed over all the crystal lattice. It is argued that the spontaneous FM order in y=0 and the existence of strong FM correlations in y=0.15 apparently contradict the single t2g band character of LS/LS phase. The explanation we suggest relies on a model of the defect-induced, itinerant hole-mediated magnetism, where the defects are identified with the magnetic high-spin Co3+ species stabilized near oxygen vacancies.

Superionic Conductivity of Sm3+, Pr3+, and Nd3+ Triple-Doped Ceria through Bulk and Surface Two-Step Doping Approach.

Science.gov (United States)

Liu, Yanyan; Fan, Liangdong; Cai, Yixiao; Zhang, Wei; Wang, Baoyuan; Zhu, Bin

2017-07-19

Sufficiently high oxygen ion conductivity of electrolyte is critical for good performance of low-temperature solid oxide fuel cells (LT-SOFCs). Notably, material conductivity, reliability, and manufacturing cost are the major barriers hindering LT-SOFC commercialization. Generally, surface properties control the physical and chemical functionalities of materials. Hereby, we report a Sm 3+ , Pr 3+ , and Nd 3+ triple-doped ceria, exhibiting the highest ionic conductivity among reported doped-ceria oxides, 0.125 S cm -1 at 600 °C. It was designed using a two-step wet-chemical coprecipitation method to realize a desired doping for Sm 3+ at the bulk and Pr 3+ /Nd 3+ at surface domains (abbreviated as PNSDC). The redox couple Pr 3+ /Pr 4+ contributes to the extraordinary ionic conductivity. Moreover, the mechanism for ionic conductivity enhancement is demonstrated. The above findings reveal that a joint bulk and surface doping methodology for ceria is a feasible approach to develop new oxide-ion conductors with high impacts on advanced LT-SOFCs.

ETR fuel element shipping container addendum to PR-T-79-011 (TR-466). Internal technical report

International Nuclear Information System (INIS)

Smith, M.C.

1979-01-01

In July, 1979, EG and G Idaho, Inc. was requested to evaluate the ETR Fuel Element Shipping Container for compliance with existing transport regulations, in order to ship GETR fuel elements from Vallecitos, California to the INEL. Technical report PR-T-79-011 (TR-466), ATR Fuel Element Shipping Container Safety Analysis, was used as a basis for this evaluation. The safety analysis contained in technical report PR-T-79-011 (TR-466) was performed utilizing the ATR, ETR, MTR, and SPERT shipping containers. The report determined the ETR Fuel Element Shipping Container does comply with the existing transport regulations for a Type A quantity, Fissile Class I shipping container. The ETR and GETR fuel elements are essentially identical in physical size, construction, and fissile material content, the analysis documented in this report has determined the shipment of GETR fuel elements in the ETR shipping container to be safe and pose no threat to the public health and safety

Oxidation of Helix-3 methionines precedes the formation of PK resistant PrP.

Directory of Open Access Journals (Sweden)

Tamar Canello

2010-07-01

Full Text Available While elucidating the peculiar epitope of the alpha-PrP mAb IPC2, we found that PrPSc exhibits the sulfoxidation of residue M213 as a covalent signature. Subsequent computational analysis predicted that the presence of sulfoxide groups at both Met residues 206 and 213 destabilize the alpha-fold, suggesting oxidation may facilitate the conversion of PrPC into PrPSc. To further study the effect of oxidation on prion formation, we generated pAbs to linear PrP peptides encompassing the Helix-3 region, as opposed to the non-linear complexed epitope of IPC2. We now show that pAbs, whose epitopes comprise Met residues, readily detected PrPC, but could not recognize most PrPSc bands unless they were vigorously reduced. Next, we showed that the alpha-Met pAbs did not recognize newly formed PrPSc, as is the case for the PK resistant PrP present in lines of prion infected cells. In addition, these reagents did not detect intermediate forms such as PK sensitive and partially aggregated PrPs present in infected brains. Finally, we show that PrP molecules harboring the pathogenic mutation E200K, which is linked to the most common form of familial CJD, may be spontaneously oxidized. We conclude that the oxidation of methionine residues in Helix-3 represents an early and important event in the conversion of PrPC to PrPSc. We believe that further investigation into the mechanism and role of PrP oxidation will be central in finally elucidating the mechanism by which a normal cell protein converts into a pathogenic entity that causes fatal brain degeneration.

1D and 2D assembly structures by imidazole···chloride hydrogen bonds of iron(II) complexes [Fe(II)(HL(n-Pr))3]Cl·Y (HL(n-Pr) = 2-methylimidazol-4-yl-methylideneamino-n-propyl; Y = AsF6, BF4) and their spin states.

Science.gov (United States)

Fujinami, Takeshi; Nishi, Koshiro; Matsumoto, Naohide; Iijima, Seiichiro; Halcrow, Malcolm A; Sunatsuki, Yukinari; Kojima, Masaaki

2011-12-07

Two Fe(II) complexes fac-[Fe(II)(HL(n-Pr))(3)]Cl·Y (Y = AsF(6) (1) and BF(4) (2)) were synthesized, where HL(n-Pr) is 2-methylimidazole-4-yl-methylideneamino-n-propyl. Each complex-cation has the same octahedral N(6) geometry coordinated by three bidentate ligands and assumes facial-isomerism, fac-[Fe(II)(HL(n-Pr))(3)](2+) with Δ- and Λ-enantiomorphs. Three imidazole groups per Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) are hydrogen-bonded to three Cl(-) ions or, from the viewpoint of the Cl(-) ion, one Cl(-) ion is hydrogen-bonded to three neighbouring fac-[Fe(II)(HL(n-Pr))(3)](2+) cations. The 3 : 3 NH···Cl(-) hydrogen bonds between Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) and Cl(-) generate two kinds of assembly structures. The directions of the 3 : 3 NH···Cl(-) hydrogen bonds and hence the resulting assembly structures are determined by the size of the anion Y, though Y is not involved into the network structure and just accommodated in the cavity. Compound 1 has a 1D ladder structure giving a larger cavity, in which the Δ- and Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) enantiomorphs are bridged by two NH···Cl(-) hydrogen bonds. Compound 2 has a 2D network structure with a net unit of a cyclic trimer of {fac-[Fe(II)(HL(n-Pr))(3)](2+)···Cl(-)}(3) giving a smaller cavity, in which Δ- or Λ-fac-[Fe(II)(HL(n-Pr))(3)](2+) species with the same chirality are linked by NH···Cl(-) hydrogen bonds to give a homochiral 2D network structure. Magnetic susceptibility and Mössbauer spectral measurements demonstrated that compound 1 showed an abrupt one-step spin crossover with 4.0 K thermal hysteresis of T(c↓) = 125.5 K and T(c↑) = 129.5 K and compound 2 showed no spin transition and stayed in the high-spin state over the 5-300 K temperature range.

Investigation of magnetocaloric effect in La0.45Pr0.25Ca0.3MnO3 by magnetic, differential scanning calorimetry and thermal analysis

International Nuclear Information System (INIS)

Aparnadevi, M.; Barik, S.K.; Mahendiran, R.

2012-01-01

We investigated magnetocaloric effect in La 0.45 Pr 0.25 Ca 0.3 MnO 3 by direct methods (changes in temperature and latent heat) and indirect method (magnetization isotherms). This compound undergoes a first-order paramagnetic to ferromagnetic transition with T C =200 K upon cooling. The paramagnetic phase becomes unstable and it transforms into a ferromagnetic phase under the application of magnetic field, which results in a field-induced metamagnetic transition (FIMMT). The FIMMT is accompanied by release of latent heat and temperature of the sample as evidenced from differential scanning calorimetry and thermal analysis experiments. A large magnetic entropy change of ΔS m =−7.2 J kg −1 K −1 at T=212.5 K and refrigeration capacity of 228 J kg −1 are found for a field change of ΔH=5 T. It is suggested that destruction of magnetic polarons and growth of ferromagnetic phase accompanied by a lattice volume change with increasing magnetic field is responsible for the large magnetocaloric effect in this compound. - Highlights: ► We report magnetic entropy change measured by indirect and direct methods in La 0.45 Pr 0.25 Ca 0.3 MnO 3. ► Anomalous field-induced induced metamagnetic transition is found in the paramagnetic state. ► A large reversible magnetic entropy change (ΔS m =7.2 J kg −1 K −1 for ΔH=5 T). ► A large refrigeration capacity (RC=228 J kg −1 ). ► Collapse of magnetic polarons is suggested as possible origin of the large MCE.

White light generation from YAG/YAM:Ce{sup 3+}, Pr{sup 3+}, Cr{sup 3+} nanophosphors mixed with a blue dye under 340 nm excitation

Energy Technology Data Exchange (ETDEWEB)

Oliva, J. [Centro de Investigaciones en Optica, A.P. 1-948, León, Gto 37150, México (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Optica, A.P. 1-948, León, Gto 37150, México (Mexico); Diaz-Torres, L.A [Centro de Investigaciones en Optica, A.P. 1-948, León, Gto 37150, México (Mexico); Torres, A. [Universidad Autónoma de Nuevo León, A.P. 126-F, Monterrey, NL 66450, México (Mexico); Salas, P. [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Juriquilla, Qro. 76000, México (Mexico); Meza, O. [Benemérita Universidad Autónoma de Puebla, 4 Sur 104 Centro Historico, 72000 Puebla, México (Mexico)

2014-10-15

The structural and luminescent properties of Y{sub 3}Al{sub 5}O{sub 12}/Y{sub 4}Al{sub 2}O{sub 9}:Ce{sup 3+}(0.1%)–Pr{sup 3+}(0.1%) –Cr{sup 3+} (trace impurities) nanophosphors synthesized by a simple hydrothermal method were studied. The crystalline phase was composed of Yttrium Aluminum Garnet (YAG) and Yttrium Aluminum Monoclinic (YAM) depending on the ammonia concentration and annealing temperature. Ammonia increased the stabilization of YAG from 55 wt% to 63 wt% in the samples annealed at 900 °C, and an increment of 83% of the overall emission under 460 nm excitation was observed. Quenching of the emitted signal after annealing at 1100 °C was observed in spite of single YAG crystalline phase stabilization, due to the formation of Ce{sup 4+}, Pr{sup 4+}, and color centers. In addition to the green–yellow emission from Ce{sup 3+}, all samples present a broad red emission band produced by the relaxations from the broad band {sup 4}T{sub 2} toward the {sup 4}A{sub 2} energy level of Cr{sup 3+} impurities, under 340 nm excitation. By taking advantage of this broad green–yellow–red emission and using a blue dye, white light with CIE coordinates of (0.30, 0.36) under 340 nm excitation was produced. - Highlights: • YAG/YAM:Ce{sup 3+}, Pr{sup 3+}, Cr{sup 3+} nanophosphors were synthesized with a hydrothermal method. • Ammonia introduced during the synthesis increased the emission of nanophosphors. • White light was obtained by combining the emissions of a blue dye and nanophosphors. • The CIE coordinates for this white light are (0.30, 0.36)

Relationship between electrical and structural properties in Pr2/3+xTiO3±y

International Nuclear Information System (INIS)

Kirsanov, N.A.; Bazuev, G.V.

1987-01-01

Synthesis conditions results of X-ray diffraction investigations and electric properties of oxide titanium bronzes (OTB) of praseodymium Pr 2/3+x TiO 3±y in homogeneity region are presented. Change of crystal lattice symmetry in the region of existence of oxide titanium bronzes Pr 2/3+x TiO 3 ± y (O ≤ x ≤ 1/3) was revealed. Specific electrical resistance measurements enabled to conclude that d-electrons of Ti 3+ cations were characterized by collectivized behaviour, conditioned by formation of harrow, partially occupied π*-zone

Mass spectrometric investigation of neutral and charged constituents in saturated vapor over PrI3

International Nuclear Information System (INIS)

Motalov, V.B.; Vorobiev, D.E.; Kudin, L.S.; Markus, T.

2009-01-01

The Knudsen effusion mass spectrometric technique was used to study vapor species over praseodymium triiodide. The monomer, PrI 3 , and dimer, Pr 2 I 6 , molecules and the negative ions, PrI 4 - and Pr 2 I 7 - , were observed in saturated vapor in the temperature range from 856 K to 1048 K. The partial vapor pressures of neutral constituents were determined and the enthalpies of sublimation obtained using the second and the third laws of thermodynamics (Δ s H deg. (298.15 K) = 291 ± 4 kJ mol -1 for PrI 3 , and Δ s H deg. (298.15 K) = 400 ± 30 kJ mol -1 for Pr 2 I 6 ). The equilibrium constants for various ion molecular reactions were measured and the enthalpies of reactions obtained. The enthalpies of formation, Δ f H deg. (298.15 K) kJ mol -1 , of gaseous molecules and ions were calculated and are as follows: -374 ± 6 (PrI 3 ), -929 ± 30 (Pr 2 I 6 ), -867 ± 30 (PrI 4 - ), -1432 ± 50 (Pr 2 I 7 - )

Thermal Behaviour of Sm0.5 R 0.5FeO3 (R = Pr, Nd) Probed by High-Resolution X-ray Synchrotron Powder Diffraction.

Science.gov (United States)

Pavlovska, Olena; Vasylechko, Leonid; Buryy, Oleh

2016-12-01

Mixed ferrites Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 with orthorhombic perovskite structure isotypic with GdFeO3 were synthesized by solid-state reaction technique in air at 1473 K. Structural parameters obtained at room temperature prove a formation of continuous solid solutions in the SmFeO3-PrFeO3 and SmFeO3-NdFeO3 pseudo-binary systems. Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 show strongly anisotropic nonlinear thermal expansion: thermal expansion in the b direction is twice lower than in the a and c directions. The average linear thermal expansion coefficients of Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 in the temperature range of 298-1173 K are in the limits of (9.0-11.1) × 10(-6) K(-1), which is close to the values reported for the parent RFeO3 compounds. Subtle anomalies in the lattice expansion of Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 detected at 650-750 K reflect magnetoelastic coupling at the magnetic ordering temperature T N.

Optimization of Pr3+:ZBLAN fiber amplifiers

DEFF Research Database (Denmark)

Pedersen, B.; Miniscalco, J. W.; Quimby, R. S.

1992-01-01

Experimental parameters have been measured and used in a quantitative model of Pr3+-doped fluorozirconate fiber amplifiers. The optimum cutoff wavelength was determined to be 800 nm and the gain for 400 mW of pump was found to increase from 12 to 34 dB if the NA was increased from 0.15 to 0...

Cs2SO4-Pr2(SO4)3-H2O and NiSO4-Pr2(SO4)3-H2O systems at 75 deg C

International Nuclear Information System (INIS)

Onishchenko, M.K.; Skorikov, V.M.; Shevchuk, V.G.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

1979-01-01

To investigate physico-chemical properties of equilibrium saturated solutions and to elucidate the chemical changes under way, the aqueous systems of cesium, nickel and praseodymium (3) sulfates are studied. The method of isothermal saturation of salts at 75 deg C is used. It has been found that in the system Cs 2 SO 4 -Pr 2 (SO 4 ) 3 -H 2 O in a wide concentration range the soluble binary salt Cs 2 SO 4 xPr 2 (SO 4 ) 3 csytallizes in a congruent way. For the system NiSO 4 -Pr 2 (SO 4 ) 3 -H 2 O a solubility curve of the eutonic type is obtained, there being no chemical interaction between the components. The solubility isotherms for the system are given

Structure and Electrical-Transport Relations in Ba(Zr,Pr)O3-δ Perovskites.

Science.gov (United States)

Antunes, Isabel; Amador, Ulises; Alves, Adriana; Correia, Maria Rosário; Ritter, Clemens; Frade, Jorge Ribeiro; Pérez-Coll, Domingo; Mather, Glenn C; Fagg, Duncan Paul

2017-08-07

Members of the perovskite solid solution BaZr 1-x Pr x O 3-δ (0.2 ≤ x ≤ 0.8) with potential high-temperature electrochemical applications were synthesized via mechanical activation and high-temperature annealing at 1250 °C. Structural properties were examined by Rietveld analysis of neutron powder diffraction and Raman spectroscopy at room temperature, indicating rhombohedral symmetry (space group R3̅c) for members x = 0.2 and 0.4 and orthorhombic symmetry (Imma) for x = 0.6 and 0.8. The sequence of phase transitions for the complete solid solution from BaZrO 3 to BaPrO 3 is Pm3̅m → R3̅c → Imma → Pnma. The structural data indicate that Pr principally exists as Pr 4+ on the B site and that oxygen content increases with higher Pr content. Electrical-conductivity measurements in the temperature range of 250-900 °C in dry and humidified (pH 2 O ≈ 0.03 atm) N 2 and O 2 atmospheres revealed an increase of total conductivity by over 2 orders of magnitude in dry conditions from x = 0.2 to x = 0.8 (σ ≈ 0.08 S cm -1 at 920 °C in dry O 2 for x = 0.8). The conductivity for Pr contents x > 0.2 is attributable to positively charged electronic carriers, whereas for x = 0.2 transport in dry conditions is n-type. The change in conduction mechanism with composition is proposed to arise from the compensation regime for minor amounts of BaO loss changing from predominantly partitioning of Pr on the A site to vacancy formation with increasing Pr content. Conductivity is lower in wet conditions for x > 0.2 indicating that the positive defects are, to a large extent, charge compensated by less mobile protonic species. In contrast, the transport mechanism of the Zr-rich composition (x = 0.2), with much lower electronic conductivity, is essentially independent of moisture content.

Locoregional deformation pattern of the patellar cartilage after different loading types. High-resolution 3D-MRI volumetry at 3 T in-vivo; Lokoregionaere Deformationsmuster im Patellarknorpel nach unterschiedlichen Belastungsparadigmen. Hochaufloesende 3-D-MR-Volumetrie bei 3 T in vivo

Energy Technology Data Exchange (ETDEWEB)

Horng, Annie [University Hospital LMU Munich, Muenchen (Germany). Radiology; Raya, J. [New York Univ. Medical Center, NY (United States). Center of Biomedical Imaging; Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Grosshadern (Germany). Inst. fuer Klinische Radiologie; Zscharn, M. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Grosshadern (DE). Inst. fuer Klinische Radiologie] (and others)

2011-05-15

Purpose: To analyze locoregional deformation patterns indicative of contact areas in patellar cartilage after different loading exercises. Materials and Methods: 7 healthy patellae were examined in-vivo before and immediately after standardized loading (kneeling, squatting or knee bends) and after 90 minutes of rest using a sagittal 3D-T1-w FLASH WE sequence (22 msec/ 9.8msec/ 15 / 0.3 x 0.3 x 1.5 mm{sup 3}) at 3 T. After cartilage segmentation and 3D reconstruction, voxel-based and global precision errors (PR) were calculated. The former were used to determine significant differences in local cartilage thickness. Voxel-based 2{sigma}-thickness difference maps were calculated to visualize locoregional deformation patterns. Global changes in volume (Vol), mean thickness (mTh) and cartilage-bone-interface area (CBIA) were calculated. Results: The voxel-based PR depended on cartilage thickness (D) ranging from 0.12 - 0.35 mm. For D {>=} 1 mm the RF was < 0.31 mm (< voxel size), and for D {>=} 2 mm, the RF was < 0.22 mm. The global PR was 83 mm{sup 3} (2.4 %) for Vol, 0.06 mm (2.0 %) for mTh and 16 mm{sup 2} (1.4 %) for CBIA. The focal cartilage deformation equaled 14 % of the local thickness reduction. The deformation areas were oval and located in the peripheral medial (more vertically oriented, all exercises) and caudo-lateral (more horizontally oriented, kneeling and knee bends) aspects of the patella and were least pronounced in knee bends. Significant changes for Vol/mTh ranged from 2.1 to 3.7 %. Conclusion: This MRI-based study is the first to identify in-vivo voxel-based patellar cartilage deformation patterns indicating contact and loading zones after kneeling and squatting. These zones are anatomically and functionally plausible and may represent areas where stress induced degeneration and subsequent OA can originate. The data may facilitate understanding of individual knee loading properties and help to improve and validate biomechanical models for the knee

Luminescent characteristics of UV excited Sr_0_._5Ca_0_._5TiO_3: Pr"3"+ reddish-orange phosphor

International Nuclear Information System (INIS)

Vidyadharan, Viji; Mohan P, Remya; Joseph, Cyriac; Unnikrishnan, N.V.; Biju, P.R.

2016-01-01

Pr"3"+ doped Sr_0_._5Ca_0_._5TiO_3 phosphors were synthesised by solid state reaction process. The structure, surface morphology and photoluminescence of the prepared phosphors were analysed using XRD, SEM and photoluminescence spectroscopy respectively. The XRD pattern confirmed orthorhombic perovskite structure of the Sr_0_._5Ca_0_._5TiO_3: x Pr"3"+ phosphor. Agglomeration of particles with irregular shapes is observed from the SEM images. The emission spectra of Sr_0_._5Ca_0_._5TiO_3: x Pr"3"+ phosphor shows the samples can be effectively excited with UV light at 336 nm and exhibit a strong reddish-orange emission at 611 nm. Concentration dependence of emission intensity shows concentration quenching effect on increasing Pr"3"+ concentration after x = 0.1 because of dipole–dipole interaction. Using Blasse's formula, critical distance for energy transfer was calculated. The CIE co-ordinates, CCT, colour purity and luminescence decay of the prepared phosphors were also calculated. These results offer the prepared phosphor as a suitable candidate for various photonic applications. - Highlights: • Sr_0_._5Ca_0_._5TiO_3: x Pr"3"+ perovskite structured phosphors were synthesized. • Under UV excitation, the PL spectra show strong reddish-orange emission. • The emission from "3P_J levels of Pr"3"+ were absent due to the presence of IVCT band. • Concentration quenching due to dipole–dipole interaction was observed. • For x = 0.1, sample shows a maximum emission intensity with 91.7% colour purity.

LiY0.3Lu0.7F4: Ce3+,Pr3+ Mixed Crystal as a Perspective Up-Conversionally Pumped UV Active Medium

Directory of Open Access Journals (Sweden)

Gorieva V.G.

2015-01-01

Full Text Available Investigation results of effective population of states of 5d-configuration of Ce3+ ions by energy transfer from Pr3+ ions in LiY0.3Lu0.7F4 (LYLF crystals are discussed. The real concentrations of Pr3+ and Ce3+ ions in LYLF crystals are determined. Such parameters as excited 4f-5d state photoionization cross-section of Pr3+ ions, ground state cross-section of Ce3+ ions at 266 nm wavelengths and energy transfer coefficients of energy transfer from Pr3+ to Ce3+ ions were estimated. The results of pump-probe experiments on 5d-4f transitions of Ce3+ ions in LYLF crystals are presented. The optimal parameters for getting maximal gain on 5d-4f transitions of Ce3+ ions were determined by mathematical modeling.

Thermoluminescent response of LaAlO3:Pr

International Nuclear Information System (INIS)

Morales H, A.; Zarate M, J.; Azorin N, J.; Rivera M, T.

2015-10-01

In this study, the thermoluminescence response of doped lanthanum aluminate (LaAlO 3 ) with praseodymium ion (Pr) obtained by the Pechini method and drying by the spraying technique Spry Dryer was studied. The obtained powders were analyzed structurally by the X-ray diffraction technique; the morphological characterization was by the scanning electron microscopy technique. The obtained powders at 800 degrees C presented crystallinity and showed a Rhombohedral crystal structure, this phase was observed by X-ray diffraction patterns. Thermoluminescence response of LaAlO 3 :Pr showed a brightness curve with a peak centered at 157 degrees C. The sensitivity of the doped samples was improved about 90 times in comparison with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 230 nm, reproducibility of thermoluminescence response was ±50%. Also the fading in thermoluminescence response was studied. (Author)

Stress-induced metallic behavior under magnetic field in Pr1-xCaxMnO3 (x=0.5 and 0.4) thin films (invited)

International Nuclear Information System (INIS)

Prellier, W.; Simon, Ch.; Mercey, B.; Hervieu, M.; Haghiri-Gosnet, A. M.; Saurel, D.; Lecoeur, Ph.; Raveau, B.

2001-01-01

We have investigated the role of the stress induced by the presence of the substrate in thin films of colossal magnetoresistive manganites on structural, resistive, and magnetic properties. Because of the strong coupling between the small structural distortions related to the charge ordering (CO) and the resistive properties, the presence of the substrate prevents the full development of the charge ordering in Pr 0.5 Ca 0.5 MnO 3 , especially in the very thin films. For thicker films, the CO state exists, but is not fully developed. Correlatively, the magnetic field which is necessary to suppress the CO is decreased drastically from 25 T to about 5 T on SrTiO 3 substrates. We have also investigated the influence of the doping level by studying the case of Pr 0.6 Ca 0.4 MnO 3 . [copyright] 2001 American Institute of Physics

Atomically layer-by-layer diffusion of oxygen/hydrogen in highly epitaxial PrBaCo{sub 2}O{sub 5.5+δ} thin films

Energy Technology Data Exchange (ETDEWEB)

Bao, Shanyong; Xu, Xing; Enriquez, Erik; Mace, Brennan E.; Chen, Garry; Kelliher, Sean P.; Chen, Chonglin, E-mail: cl.chen@utsa.edu [Department of Physics and Astronomy, University of Texas, San Antonio, Texas 78249 (United States); Zhang, Yamei [Department of Physics, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Whangbo, Myung-Hwan [North Carolina State University, Raleigh, North Carolina 27695-8204 (United States); Dong, Chuang; Zhang, Qinyu [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China)

2015-12-14

Single-crystalline epitaxial thin films of PrBaCo{sub 2}O{sub 5.5+δ} (PrBCO) were prepared, and their resistance R(t) under a switching flow of oxidizing and reducing gases were measured as a function of the gas flow time t in the temperature range of 200–800 °C. During the oxidation cycle under O{sub 2}, the PrBCO films exhibit fast oscillations in their dR(t)/dt vs. t plots, which reflect the oxidation processes, Co{sup 2+}/Co{sup 3+} → Co{sup 3+} and Co{sup 3+} → Co{sup 3+}/Co{sup 4+}, that the Co atoms of PrBCO undergo. Each oscillation consists of two peaks, with larger and smaller peaks representing the oxygen/hydrogen diffusion through the (BaO)(CoO{sub 2})(PrO)(CoO{sub 2}) layers of PrBCO via the oxygen-vacancy-exchange mechanism. This finding paves a significant avenue for cathode materials operating in low-temperature solid-oxide-fuel-cell devices and for chemical sensors with wide range of operating temperature.

Donor doping process and white light generation in CaMoO4 powders with multivalence Pr codoping

International Nuclear Information System (INIS)

Zhu Fang; Xiao Zhisong; Zhang Feng; Yan Lu; Huang Anping

2011-01-01

Both trivalent praseodymium (Pr 3+ ) and quadrivalent praseodymium (Pr 4+ ) were doped in molybdate powders. Visible emission from matrix was enhanced by multivalent Pr codoping. It was proposed that Pr 3+ ions was donor and supplied quasi-free electron when Pr 3+ took place the Pr 4+ sites. The result showed that multivalence codoping would be an effective way to enhance emission of CaMoO 4 . White light can be generated from Ca 0.98 Pr 0.02 MoO 4 powder via combination of broadband emissions originated from CaMoO 4 matrix and radiative transition of Pr 3+ . It showed warm white light with T c of 3450 K that implies promising application in white light emitting diodes (LEDs).

Isothermal sections of the state diagram for the Pr-Ni-Ge system at 870 (0-0,5Pr) and 670 K (0,5-1Pr)

International Nuclear Information System (INIS)

Fedyna, M.F.; Pecharskij, V.K.; Bodak, O.I.

1987-01-01

Method of X-ray phase and microstructural analyses were used to study Pr-Ni-Ge ternary system at 870K (0-0.50 at.fractions of Pr) and 670K (0.50-1.00 at.fractions of Pr). 11 ternary compounds exist in the system: Pr 1-x (NiGe) 13 (x=0.24), PrNi 2 Ge 2 , Pr 2 Ni 3 Ge 5 , PrNiGe 3 , Pr 2 NiGe 6 , Pr 3 Ni 4 Ge 4 , PrNi (1-x) Ge 2 (x=0.33), PrNiGe, Pr(NiGe) 2-x (x=0.14), Pr 3 NiGe 2 , ∼Pr 5 NiGe 4 . Crystal structure was determined for seven ternary compounds

Photoluminescent properties of Pr3+ doped YTiAO6 (A= Nb&Ta) euxenite compounds

Science.gov (United States)

Venugopal, Meenu; Kumar, H. Padma

2018-04-01

Pr3+ doped YTiAO6 (A = Nb and Ta) compounds were prepared by conventional solid state ceramic route. X - ray diffraction studies of the samples confirmed the euxenite orthorhombic phase formation. Effect of Pr3+ doping on the optical and luminescence properties of YTiAO6 (A = Nb and Ta) were studied. The strong absorption in the UV region are due to the absorption by the host YTiAO6 (A = Nb and Ta) and all other peaks can be attributed to that of Pr3+. Host emission peaks are observed around 485 nm and 460 nm in all samples. The red emission observed at 614 nm in the doped samples corresponds to the 1D2 to 3H4 transition of Pr3+ ion. CIE colour coordinates and chromaticity values were also discussed.

Early Delivery of Misfolded PrP from ER to Lysosomes by Autophagy

Science.gov (United States)

Cortes, Constanza J.; Qin, Kefeng; Norstrom, Eric M.; Green, William N.; Bindokas, Vytautas P.; Mastrianni, James A.

2013-01-01

Prion diseases are linked to the accumulation of a misfolded isoform (PrPSc) of prion protein (PrP). Evidence suggests that lysosomes are degradation endpoints and sites of the accumulation of PrPSc. We questioned whether lysosomes participate in the early quality control of newly generated misfolded PrP. We found PrP carrying the disease-associated T182A mutation (Mut-PrP) was delivered to lysosomes in a Golgi-independent manner. Time-lapse live cell imaging revealed early formation and uptake of GFP-tagged Mut-PrP aggregates into LysoTracker labeled vesicles. Compared with Wt-PrP, Mut-PrP expression was associated with an elevation in several markers of the autophagy-lysosomal pathway, and it extensively colocalized with the autophagosome-specific marker, LC3B. In autophagy deficient (ATG5−/−) mouse embryonic fibroblasts, or in normal cells treated with the autophagy-inhibitor 3-MA, Mut-PrP colocalization with lysosomes was reduced to a similar extent. Additionally, 3-MA selectively impaired the degradation of insoluble Mut-PrP, resulting in an increase in protease-resistant PrP, whereas the induction of autophagy by rapamycin reduced it. These findings suggest that autophagy might function as a quality control mechanism to limit the accumulation of misfolded PrP that normally leads to the generation of PrPSc. PMID:24454378

Magnetic interactions in praseodymium ruthenate Pr{sub 3}RuO{sub 7} with fluorite-related structure

Energy Technology Data Exchange (ETDEWEB)

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

2017-06-15

Solid solutions Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7} (0≤x≤1.0) and (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7} (0≤x≤0.7) were obtained as a single phase compound. They crystallize in an orthorhombic superstructure derived from that of the cubic fluorite with space group Cmcm. The results of the Rietveld analysis for X-ray diffraction profiles of Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7} showed that Ru and Ta atoms are randomly situated at the six-coordinate 4b site. For (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7}, with increasing the concentration of Y ions (x value), the smaller Y ions occupy selectively the seven-coordinate 8g site rather than the eight-coordinate 4a site. Through magnetic susceptibility measurements for Pr{sub 3}(Ru{sub 1-x}Ta{sub x})O{sub 7}, the antiferromagnetic transition temperatures decrease linearly with increasing x value, and at x=0.75 no magnetic ordering was found down to 1.8 K, indicating the magnetic interaction is not one-dimensional, but three-dimensional. On the other hand, the antiferromagnetic transition temperature for (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7} decreases with increasing x value, but above x≥0.50 it becomes constant (~12 K). This result indicates that Pr{sup 3+} ions at the seven-coordinate site greatly contribute to the antiferromagnetic interactions observed in (Pr{sub 1-x}Y{sub x}){sub 3}RuO{sub 7}. Density functional calculations of Pr{sub 3}RuO{sub 7} demonstrate that the electronic structure gives insulating character and that oxygen 2p orbitals hybridize strongly with Ru 4d orbitals in the valence band (VB). Near the top of VB, the Pr 4 f orbitals at the seven-coordinated site also show a weak hybridization with the O(1) 2p orbitals. The Ru-O(1)-Pr superexchange pathway take part in three-dimensional magnetic interaction and play an important role in an enhancement of long-range magnetic ordering. - Graphical abstract: The spin densities and the spin polarization of Pr{sub 3}RuO{sub 7} are shown

Effect of oxygen isotope substitution on magnetic structure of (La0.25Pr0.75)0.7Ca0.3MnO3

International Nuclear Information System (INIS)

Balagurov, A.M.; Pomyakushin, V.Yu.; Sheptyakov, D.V.

1999-01-01

The oxygen isotope effect on the magnetic structure and charge ordering in (La 0.25 Pr 0.75 ) 0.7 Ca 0.3 MnO 3 was studied by neutron powder diffraction. At first it was found that two investigated samples, one of those contained the natural mixture of isotopes (99.7 % 16 O, metallic at T ≤ 100 K), and the other one enriched by 18 O in 75 % (insulating in all temperature range) are identical at room temperature. At the temperature lowering the sample with 16 0 undergoes subsequent antiferromagnetic (T AFM = 150 K) and ferromagnetic (T FM = 110 K) transitions, resulting in the noncollinear FM structure, while in the sample with 18 O the pure AFM ordering (T AFM = 150 K) is found. The temperature dependencies of the diffraction peak intensities associated with charge ordering are also quite different in the samples with 16 O and 18 O and correlate with the behaviour of the electrical resistivity and the magnetic structure. No indications of long-range phase segregation at low temperature were found

PR IN HIGH-TEMPERATURE SUPERCONDUCTORS - INSULATING PLANES, METALLIC CHAINS

NARCIS (Netherlands)

KHOMSKII, D

Critical discussion is given of the properties of Pr-containing high-T(c) superconductors, especially Y1-xPrxBa2Cu3O7. It is argued that the models proposed to explain suppression of T(c) and other properties of this system (pairbreaking; hole filling; strong p-f hybridization) are inadequate and

PR-EDB: Power Reactor Embrittlement Database Version 3

International Nuclear Information System (INIS)

Wang, Jy-An John; Subramani, Ranjit

2008-01-01

The aging and degradation of light-water reactor pressure vessels is of particular concern because of their relevance to plant integrity and the magnitude of the expected irradiation embrittlement. The radiation embrittlement of reactor pressure vessel materials depends on many factors, such as neutron fluence, flux, and energy spectrum, irradiation temperature, and preirradiation material history and chemical compositions. These factors must be considered to reliably predict pressure vessel embrittlement and to ensure the safe operation of the reactor. Large amounts of data from surveillance capsules are needed to develop a generally applicable damage prediction model that can be used for industry standards and regulatory guides. Furthermore, the investigations of regulatory issues such as vessel integrity over plant life, vessel failure, and sufficiency of current codes, Standard Review Plans (SRPs), and Guides for license renewal can be greatly expedited by the use of a well-designed computerized database. The Power Reactor Embrittlement Database (PR-EDB) is such a comprehensive collection of data for U.S. designed commercial nuclear reactors. The current version of the PR-EDB lists the test results of 104 heat-affected-zone (HAZ) materials, 115 weld materials, and 141 base materials, including 103 plates, 35 forgings, and 3 correlation monitor materials that were irradiated in 321 capsules from 106 commercial power reactors. The data files are given in dBASE format and can be accessed with any personal computer using the Windows operating system. 'User-friendly' utility programs have been written to investigate radiation embrittlement using this database. Utility programs allow the user to retrieve, select and manipulate specific data, display data to the screen or printer, and fit and plot Charpy impact data. The PR-EDB Version 3.0 upgrades Version 2.0. The package was developed based on the Microsoft .NET framework technology and uses Microsoft Access for

PR-EDB: Power Reactor Embrittlement Database - Version 3

Energy Technology Data Exchange (ETDEWEB)

Wang, Jy-An John [ORNL; Subramani, Ranjit [ORNL

2008-03-01

The aging and degradation of light-water reactor pressure vessels is of particular concern because of their relevance to plant integrity and the magnitude of the expected irradiation embrittlement. The radiation embrittlement of reactor pressure vessel materials depends on many factors, such as neutron fluence, flux, and energy spectrum, irradiation temperature, and preirradiation material history and chemical compositions. These factors must be considered to reliably predict pressure vessel embrittlement and to ensure the safe operation of the reactor. Large amounts of data from surveillance capsules are needed to develop a generally applicable damage prediction model that can be used for industry standards and regulatory guides. Furthermore, the investigations of regulatory issues such as vessel integrity over plant life, vessel failure, and sufficiency of current codes, Standard Review Plans (SRPs), and Guides for license renewal can be greatly expedited by the use of a well-designed computerized database. The Power Reactor Embrittlement Database (PR-EDB) is such a comprehensive collection of data for U.S. designed commercial nuclear reactors. The current version of the PR-EDB lists the test results of 104 heat-affected-zone (HAZ) materials, 115 weld materials, and 141 base materials, including 103 plates, 35 forgings, and 3 correlation monitor materials that were irradiated in 321 capsules from 106 commercial power reactors. The data files are given in dBASE format and can be accessed with any personal computer using the Windows operating system. "User-friendly" utility programs have been written to investigate radiation embrittlement using this database. Utility programs allow the user to retrieve, select and manipulate specific data, display data to the screen or printer, and fit and plot Charpy impact data. The PR-EDB Version 3.0 upgrades Version 2.0. The package was developed based on the Microsoft .NET framework technology and uses Microsoft Access for

Magnetic properties of the germanides RE{sub 3}Pt{sub 4}Ge{sub 6} (RE=Y, Pr, Nd, Sm, Gd-Dy)

Energy Technology Data Exchange (ETDEWEB)

Eustermann, Fabian; Eilers-Rethwisch, Matthias; Renner, Konstantin; Hoffmann, Rolf-Dieter; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Oldenburg Univ. (Germany). Inst. fuer Chemie

2017-07-01

The germanides RE{sub 3}Pt{sub 4}Ge{sub 6} (RE=Y, Pr, Nd, Sm, Gd-Dy) have been synthesized by arc-melting of the elements followed by inductive annealing to improve the crystallinity and allow for structural order. The compounds have been studied by powder X-ray diffraction; additionally the structure of Y{sub 3}Pt{sub 4}Ge{sub 6} has been refined from single-crystal X-ray diffractometer data. It exhibits a (3+1)D modulated structure, indicating isotypism with Ce{sub 3}Pt{sub 4}Ge{sub 6}. The crystal structure can be described as an intergrowth between YIrGe{sub 2}- and CaBe{sub 2}Ge{sub 2}-type slabs along [100]. Temperature-dependent magnetic susceptibility measurements showed Pauli paramagnetism for Y{sub 3}Pt{sub 4}Ge{sub 6} and Curie-Weiss paramagnetism for Pr{sub 3}Pt{sub 4}Ge{sub 6} and Nd{sub 3}Pt{sub 4}Ge{sub 6}. Sm{sub 3}Pt{sub 4}Ge{sub 6} exhibits van Vleck paramagnetism, while antiferromagnetic ordering at T{sub N}=8.1(1) K and T{sub N}=11.0(1) K is observed for Gd{sub 3}Pt{sub 4}Ge{sub 6} and Tb{sub 3}Pt{sub 4}Ge{sub 6}, respectively.

Magnetic properties of PrMn2-xFexGe2-57Fe Moessbauer spectroscopy

International Nuclear Information System (INIS)

Wang, J L; Campbell, S J; Cadogan, J M; Tegus, O; Studer, A J; Hofmann, M

2006-01-01

We have investigated the magnetic behaviour of PrMn 2-x Fe x Ge 2 compounds with x = 0.4, 0.6 and 0.8 over the temperature range 4.2-350 K using ac magnetic susceptibility, dc magnetization and 57 Fe Moessbauer effect spectroscopy, as well as neutron diffraction for the PrMn 1.2 Fe 0.8 Ge 2 compound. Replacement of Mn with Fe leads to contraction of the unit cell and a shortening of the Mn-Mn spacing, resulting in modification of the magnetic structure. PrMn 1.6 Fe 0.4 Ge 2 is an intralayer antiferromagnet at room temperature and ferromagnetic below T C inter ∼230 K with additional ferromagnetic ordering of the Pr sublattice detected below T C Pr ∼30 K. Re-entrant ferromagnetism has been observed in PrMn 1.4 Fe 0.6 Ge 2 with four magnetic transitions (T N intra ∼333 K, T C inter ∼168 K, T N inter ∼152 K and T C Pr ∼40 K). Moreover, it was found that T C inter and T C Pr increase with applied field while T N inter decreases. PrMn 1.2 Fe 0.8 Ge 2 is antiferromagnetic with T N intra ∼242 K and T N inter ∼154 K. The magnetic transition temperatures for all compounds are also marked by changes in the 57 Fe magnetic hyperfine field and the electric quadrupole interaction parameters. The 57 Fe transferred hyperfine field at 4.5 K in PrMn 1.6 Fe 0.4 Ge 2 and PrMn 1.4 Fe 0.6 Ge 2 is reduced (below the ordering temperature of the Pr sublattice) compared with that at 80 K (above T C Pr ), indicating that the transferred hyperfine field from Pr acts in the opposite direction to that from the Mn atoms. The neutron data for PrMn 1.2 Fe 0.8 Ge 2 demonstrate that an anisotropic thermal expansion occurs within the interplanar antiferromagnetic range

Photon Echoes in the 3P0 ← 3H4 Transition of Pr3+/LaF3

NARCIS (Netherlands)

Morsink, Jos B.W.; Wiersma, Douwe A.

1979-01-01

Photon-echo quantum beats observed in the two-pulse and three-pulse photon echo of the 3P0 ← 3H4 transition in Pr3+/LaF3 were used to determine the excited-state spin-hamiltonian. In addition we report on the anomalous stimulated photon echo observed in the same transition which in a magnetic field

Effects of Ce3+ concentration, beam voltage and current on the cathodoluminescence intensity of SiO2: Pr3+–Ce3+ nanophosphor

CSIR Research Space (South Africa)

Mhlongo, GH

2011-02-01

Full Text Available SiO2:Pr3+–Ce3+ phosphor powders were successfully prepared using a sol–gel process. The concentration of Pr3+ was fixed at 0.2 mol% while that of Ce3+ was varied in the range of 0.2–2 mol%. High resolution transmission electron microscopy (HRTEM...

Indication for a chiral phase in the molecular magnetic chain Gd(hfac)3NiTiPr by specific heat and μ+SR measurements

International Nuclear Information System (INIS)

Lascialfari, A.; Ullu, R.; Affronte, M.; Cinti, F.; Caneschi, A.; Gatteschi, D.; Rovai, D.; Pini, M.G.; Rettori, A.

2004-01-01

Specific heat and muon spin relaxation (μ + SR) measurements performed in the molecular magnetic chain Gd(hfac) 3 NiTiPr provide indication for the onset, at T 0 =2.08 K, of a phase with chiral order in the absence of long-range helical order. Specific heat data (probing the chirality-chirality correlation function) show a peak at T 0 that disappears upon application of a 5 T magnetic field, while μ + SR data (probing the spin-spin correlation function) do not present any anomaly at T 0 nor oscillations in the asymmetry curve below T 0

Synthesis and crystal structure of the isotypic rare earth thioborates Ce[BS3], Pr[BS3], and Nd[BS3

International Nuclear Information System (INIS)

Hunger, Jens; Borna, Marija; Kniep, Ruediger

2010-01-01

The orthothioborates Ce[BS 3 ], Pr[BS 3 ] and Nd[BS 3 ] were prepared from mixtures of the rare earth (RE) metals together with amorphous boron and sulfur summing up to the compositions CeB 3 S 6 , PrB 5 S 9 and NdB 3 S 6 . The following preparation routes were used: solid state reactions with maximum temperatures of 1323 K and high-pressure high-temperature syntheses at 1173 K and 3 GPa. Pr[BS 3 ] and Nd[BS 3 ] were also obtained from rare earth chlorides RECl 3 and sodium thioborate Na 2 B 2 S 5 by metathesis type reactions at maximum temperatures of 1073 K. The crystal structure of the title compounds was determined from X-ray powder diffraction data. The thioborates are isotypic and crystallize in the orthorhombic spacegroup Pna2 1 (No. 33; Z=4; Ce: a=7.60738(6)A, b=6.01720(4)A, c=8.93016(6)A; Pr: a=7.56223(4)A, b=6.00876(2)A, c=8.89747(4)A; Nd: a=7.49180(3)A, b=6.00823(2)A, c=8.86197(3)A) . The crystal structures contain isolated [BS 3 ] 3- groups with boron in trigonal-planar coordination. The sulfur atoms form the vertices of undulated kagome nets, which are stacked along [100] according to the sequence ABAB. Within these nets every second triangle is occupied by boron and the large hexagons are centered by rare earth ions, which are surrounded by overall nine sulfur species. - Abstract: Graphical Abstract Legend (TOC Figure): Table of Contents Figure The isotypic orthothioborates Ce[BS 3 ], Pr[BS 3 ] and Nd[BS 3 ] were prepared using different preparation routes. The crystal structure of the title compounds was determined from X-ray powder diffraction data. The crystal structures contain isolated [BS 3 ] 3- groups with boron in trigonal-planar coordination. The sulfur atoms form the vertices of corrugated kagome nets (sketched with blue dotted lines), which are stacked along [100] according to the sequence ABAB. Within these nets every second triangle is occupied by boron and the large hexagons are centered by rare earth ions, which are surrounded by

The analysis of strain of giant magnetoresistive Pr0.7Sr0.3MnO3/La0.5Ca0.5MnO3/Pr0.7Sr0.3MnO-3 trilayers

International Nuclear Information System (INIS)

Wang Haiou; Liu Hao; Dai Ping; Tan Weishi; Wu Xiaoshan; Jia Quanjie; Li Xiaolong

2012-01-01

Pr 0.7 Sr 0.3 MnO 3 /La 0.5 Ca 0.5 MnO 3 /Pr 0.7 Sr 0.3 MnO 3 (PSMO/LCMO/PSMO) trilayers were deposited on (001)-oriented single crystal MgO by pulsed laser deposition. The thickness of both PSMO layers was 36 nm while the thickness of LCMO layer was 6, 12, 18, 24, 30 and 36 nm, respectively. Out-of-plane and in-plane lattice parameters of trilayers were obtained by using symmetric scanning and asymmetric scanning mode of high resolution X-ray diffraction. Strain states of trilayers have been studied. The results showed that strain relaxation states of trilayers were decided by bulk strain and Jahn-Teller (JT) strain together: The mechanism for strain relaxation in trilayers is different from that for tetragonal distortion. The competition between bulk strain and Jahn-Teller (JT) strain played an important role in the magnetotransport and magnetic properties of trilayers. (authors)

Photorefractive grating formation in piezoelectric La3Ga5SiO14:Pr3+ crystals

DEFF Research Database (Denmark)

Dam-Hansen, C.; Johansen, P.M.; Fridkin, V.M.

1996-01-01

Photorefractive grating formation and erasure in piezoelectric crystals of La3Ga5SiO14:Pr3+ are presented. The specific photoconductivity and the photorefractive sensitivity are determined. The polarization dependence of the grating formation due to the bulk photovoltaic effect is shown and compa......Photorefractive grating formation and erasure in piezoelectric crystals of La3Ga5SiO14:Pr3+ are presented. The specific photoconductivity and the photorefractive sensitivity are determined. The polarization dependence of the grating formation due to the bulk photovoltaic effect is shown...... and compared favorably with the theoretical expression. This photorefractive material provides a possibility for separate investigations of the charge migration processes responsible for the photorefractive effect. (C) 1996 American Institute of Physics....

Préface

Science.gov (United States)

Chardonnet, Christian; Millot, Guy

2006-10-01

COLOQ, réunion nationale biennale initiée en 1988 par la communauté française des lasers, de l'optique non linéaire et de l'optique quantique atteint sa neuvième édition. Depuis sa création, les objectifs poursuivis sont les suivants : - réunir la communauté française des lasers, de l'optique non linéaire et de l'optique quantique, en dépassant les clivages fondamental/appliqué, recherche publique/industrielle, - faire le point sur les avancées récentes, - permettre aux jeunes chercheurs de se rencontrer, de s'exprimer et de s'aguerrir au plan national. Le but est que tout thésard du domaine de l'optique puisse participer à COLOQ une fois durant sa thèse, présenter son travail et de se confronter à la communauté de l'optique. COLOQ9 s'est tenu, pour sa 9e édition, sur le campus universitaire de Dijon, du 7 au 9 septembre 2005. Il a été une grande réussite : nombre de participants (255) et de présentations scientifiques record (148 affiches), forte représentation des industriels (15) et participation d'environ 200 lycéens aux conférences grand public. Le nombre plus élevé que prévu d'affiches a rendu un peu serrée leur présentation : une attention particulière sera portée à cet aspect lors des prochaines éditions. Ces journées ont été consacrées à des conférences invitées données par des scientifiques de haut niveau et à des présentations sous forme d'affiches. Une plage de temps importante a été réservée pour des discussions autour des affiches. À proximité immédiate de la salle de conférence, l'exposition de matériels spécialisés pour les lasers, l'optique et l'optoélectronique a été une occasion pour les jeunes participants de découvrir et contacter les industriels et les autres grands acteurs de l'optique. L'année 2005 ayant été l'année mondiale de la physique, COLOQ9 a retenu comme thème central ”1905-2005 : à propos d'Einstein". Plusieurs grandes conférences ont été dédiées à ce th

Optical analysis of RE(3+) (RE = Pr(3) (+) , Er(3) (+) and Nd(3) (+) ):cadmium lead boro tellurite glasses.

Science.gov (United States)

Giridhar, P; Bhushana Reddy, M; Neelima, G; Ramanaiah, R; Nagamuni Reddy, K; Sahadeva Reddy, V; Sudhakar Reddy, B

2016-09-01

This article reports on the optical characterization of Pr(3) (+) -, Er(3) (+) - and Nd(3) (+) -doped cadmium lead boro tellurite (CLBT) glasses prepared using the melt quenching method. The visible-near infrared (Vis-NIR) absorption spectra of these glasses were analyzed systematically. On measuring the NIR emission spectra of Er(3) (+) :CLBT glasses, a broad emission band centered at 1536 nm ((4) I13 /2  → (4) I15 /2 ) was observed, as were three NIR emission bands at 900 nm ((4) F3 /2  → (4) I9 /2 ), 1069 nm ((4) F3 /2  → (4) I11 /2 ) and 1338 nm ((4) F3 /2  → (4) I13 /2 ) from Nd(3) (+) :CLBT glasses and an NIR emission band at 1334 nm ((1) G4  → (3) H5 ) from Pr(3) (+) :CLBT glasses at an excitation wavelength (λex ) of 514.5 nm (Ar(+) laser). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Luminescence, scintillation, and energy transfer in SiO{sub 2}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-Gd{sub 2}O{sub 3}:Ce{sup 3+},Pr{sup 3+} glasses

Energy Technology Data Exchange (ETDEWEB)

Lertloypanyachai, Prapon; Chewpraditkul, Weerapong; Pattanaboonmee, Nakarin [Department of Physics, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Chen, Danping [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai (China); Babin, Vladimir; Beitlerova, Alena; Nikl, Martin [Institute of Physics, AS CR, Prague (Czech Republic)

2017-09-15

Ce{sup 3+},Pr{sup 3+}-codoped SiO{sub 2}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-Gd{sub 2}O{sub 3} glasses (SABG:Ce,Pr) were prepared by melt quenching under a CO reducing atmosphere. Luminescence properties were investigated under UV and X-ray excitations. A dominant emission band at 430 nm belonging to the Ce{sup 3+}:5d{sub 1} → 4f transition was observed in the photo- and radio-luminescence spectra. The energy transfer occurs from this Ce{sup 3+} band toward the {sup 3}P{sub J} levels of Pr{sup 3+} with an efficiency of up to 24%, followed by the reduction of integrated luminescence intensity with an increasing Pr{sup 3+} concentration. This result is attributed to the increase in the reabsorption of Ce{sup 3+} luminescence and the non-radiative energy transfer toward the {sup 3}P{sub J} levels of Pr{sup 3+}. The cross-relaxation process within the Pr{sup 3+} pairs can further diminish the total luminescence yield at high Pr{sup 3+} concentrations. The integral scintillation efficiency and light yield measurements were carried out and compared to the reference Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) crystal. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Political PR is dying. Long live business PR! / Ilyn Oleg

Index Scriptorium Estoniae

Oleg, Ilyn

2005-01-01

Vene suurima suhtekorraldusagentuuri Imageland Public Relations rahvusvaheliste suhete juhi hinnangul on Venemaal peamisteks probleemideks PR professionaalide vähesus, nende kehv haritus oma erialal, samuti vähene teadlikkus suhtekorralduse tähtsusest äris

A importância da Terminologia para prática de revisão do texto técnico-científico

Directory of Open Access Journals (Sweden)

Bruno Diego de Resende Castro

2015-08-01

Full Text Available Este artigo objetiva mostrar a importância da Terminologia para a revisão de textos técnico-científicos segundo a visão dos próprios profissionais de revisão. Para a realização dessa observação, utilizamos como embasamento teórico as ideias de Wüster (1998 e Krieger (2001, 2004, 2013 para explicarmos a Terminologia como campo de estudos, sobretudo a concepção linguístico-textual. Já como aporte teórico para tratar da prática de revisão, utilizamos as pesquisas de Alves e Andrada (2008, Hendger e Motta-Roth (2010 e Oliveira e Macedo (2011. Analisamos o perfil dos revisores de textos técnico-científicos por meio de uma breve entrevista. Concluímos que o termo é uma preocupação central na prática de revisão de textos técnico-científicos, uma vez que é fundamental que o revisor tenha conhecimento adequado de seu sentido e uso em um contexto específico.

A simple localized-itinerant model for PrAl3: crystal field and exchange effects

International Nuclear Information System (INIS)

Ranke, P.J. von; Palermo, L.

1990-01-01

We present a simple magnetic model for PrAl sub(3). The effects of crystal field are treated using a reduced set of levels and the corresponding wave functions are extracted from the actual crystal field levels of Pr sup(+3) in a hexagonal symmetry. The exchange between 4f- and conduction electrons are dealt within a molecular field approximation. An analytical magnetic state equation is derived and the magnetic behaviour discussed. The parameters of the model are estimated from a fitting of the inverse susceptibility of PrAl sub(3) given in the literature. (author)

Diversity of PR3-ANCA epitope specificity in Wegener's granulomatosis. Analysis using the biosensor technology

NARCIS (Netherlands)

Rarok, Agnieszka; van der Geld, Y.M.; Stegeman, Coen; Limburg, Piet; Kallenberg, Cees

Wegener's granulomatosis is a systemic disease characterized by the presence of antineutrophil cytoplasm autoantibodies specific for proteinase 3 (PR3-ANCA). The functional characteristics of PR3-ANCA differ between quiescent and active disease, suggesting changes in the properties of the

Heregulin Co-opts PR Transcriptional Action Via Stat3 Role As a Coregulator to Drive Cancer Growth.

Science.gov (United States)

Proietti, Cecilia J; Izzo, Franco; Díaz Flaqué, María Celeste; Cordo Russo, Rosalía; Venturutti, Leandro; Mercogliano, María Florencia; De Martino, Mara; Pineda, Viviana; Muñoz, Sergio; Guzmán, Pablo; Roa, Juan C; Schillaci, Roxana; Elizalde, Patricia V

2015-10-01

Accumulated findings have demonstrated the presence of bidirectional interactions between progesterone receptor (PR) and the ErbB family of receptor tyrosine kinases signaling pathways in breast cancer. We previously revealed signal transducer and activator of transcription 3 (Stat3) as a nodal convergence point between said signaling pathways proving that Stat3 is activated by one of the ErbBs' ligands, heregulin (HRG)β1 via ErbB2 and through the co-option of PR as a signaling molecule. Here, we found that HRGβ1 induced Stat3 recruitment to the promoters of the progestin-regulated cell cycle modulators Bcl-XL and p21(CIP1) and also stimulated Stat3 binding to the mouse mammary tumor virus promoter, which carries consensus progesterone response elements. Interestingly, HRGβ1-activated Stat3 displayed differential functions on PR activity depending on the promoter bound. Indeed, Stat3 was required for PR binding in bcl-X, p21(CIP1), and c-myc promoters while exerting a PR coactivator function on the mouse mammary tumor virus promoter. Stat3 also proved to be necessary for HRGβ1-induced in vivo tumor growth. Our results endow Stat3 a novel function as a coregulator of HRGβ1-activated PR to promote breast cancer growth. These findings underscore the importance of understanding the complex interactions between PR and other regulatory factors, such as Stat3, that contribute to determine the context-dependent transcriptional actions of PR.

Heregulin Co-opts PR Transcriptional Action Via Stat3 Role As a Coregulator to Drive Cancer Growth

Science.gov (United States)

Izzo, Franco; Díaz Flaqué, María Celeste; Cordo Russo, Rosalía; Venturutti, Leandro; Mercogliano, María Florencia; De Martino, Mara; Pineda, Viviana; Muñoz, Sergio; Guzmán, Pablo; Roa, Juan C.; Schillaci, Roxana

2015-01-01

Accumulated findings have demonstrated the presence of bidirectional interactions between progesterone receptor (PR) and the ErbB family of receptor tyrosine kinases signaling pathways in breast cancer. We previously revealed signal transducer and activator of transcription 3 (Stat3) as a nodal convergence point between said signaling pathways proving that Stat3 is activated by one of the ErbBs' ligands, heregulin (HRG)β1 via ErbB2 and through the co-option of PR as a signaling molecule. Here, we found that HRGβ1 induced Stat3 recruitment to the promoters of the progestin-regulated cell cycle modulators Bcl-XL and p21CIP1 and also stimulated Stat3 binding to the mouse mammary tumor virus promoter, which carries consensus progesterone response elements. Interestingly, HRGβ1-activated Stat3 displayed differential functions on PR activity depending on the promoter bound. Indeed, Stat3 was required for PR binding in bcl-X, p21CIP1, and c-myc promoters while exerting a PR coactivator function on the mouse mammary tumor virus promoter. Stat3 also proved to be necessary for HRGβ1-induced in vivo tumor growth. Our results endow Stat3 a novel function as a coregulator of HRGβ1-activated PR to promote breast cancer growth. These findings underscore the importance of understanding the complex interactions between PR and other regulatory factors, such as Stat3, that contribute to determine the context-dependent transcriptional actions of PR. PMID:26340407

A combinatorial matrix of rare earth chloride mixtures as corrosion inhibitors of AA2024-T3: Optimisation using potentiodynamic polarisation and EIS

International Nuclear Information System (INIS)

Muster, T.H.; Sullivan, H.; Lau, D.; Alexander, D.L.J.; Sherman, N.; Garcia, S.J.; Harvey, T.G.; Markley, T.A.; Hughes, A.E.; Corrigan, P.A.; Glenn, A.M.; White, P.A.; Hardin, S.G.; Mardel, J.; Mol, J.M.C.

2012-01-01

A combinatorial matrix of four rare earth chlorides has been evaluated for the corrosion inhibition of aluminium alloy AA2024-T3 in aqueous solution. Two electrochemical techniques, potentiodynamic polarisation (PP) and electrochemical impedance spectroscopy (EIS), were used to evaluate AA2024-T3 corrosion in 0.1 M NaCl with the addition of 10 −3 M of rare earth chloride mixtures at time periods up to 18 h. PP experiments showed rare earth inhibition of up to 98% within the first hour and thereafter corrosion rates were steadily decreased. The open-circuit potential (OCP) of AA2024-T3 decreased as a function of time for all solutions indicating predominantly cathodic inhibition. However, differing trends in the OCP were observed during PP and EIS experiments and are discussed in terms of likely time-dependent mechanisms. A comparative study of optimisation models indicated the best mixture at 10 −3 M total inhibitor concentration was predicted to be 72% cerium (Ce) and 28% (praseodymium (Pr)/lanthanum (La)) ions. As the amount of Ce is decreased from this level the corrosion inhibition is predicted to decrease also, regardless of what other rare earths (La, Pr and Nd) are added alone or in combination. Individually, La, Pr and Nd show varying levels of corrosion inhibition activity, all of which are inferior to that of Ce. If Ce is absent entirely, then a mixture of approximately 50% Pr and 50% Nd is predicted to be preferred. This is one of the first applications of combinatorial design for the optimisation of corrosion inhibitor mixtures.

Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO 3

Science.gov (United States)

Sichelschmidt, J.; Paraskevopoulos, M.; Brando, M.; Wehn, R.; Ivannikov, D.; Mayr, F.; Pucher, K.; Hemberger, J.; Pimenov, A.; Krug von Nidda, H.-A.; Lunkenheimer, P.; Ivanov, V. Yu.; Mukhin, A. A.; Balbashov, A. M.; Loidl, A.

2001-03-01

The charge-ordered perovskite Pr0.65Ca0.28Sr0.07MnO3 was investigated by means of magnetic susceptibility, specific heat, dielectric and optical spectroscopy and electron-spin resonance techniques. Under moderate magnetic fields, the charge order melts yielding colossal magnetoresistance effects with changes of the resistivity over eleven orders of magnitude. The optical conductivity is studied from audio frequencies far into the visible spectral regime. Below the phonon modes hopping conductivity is detected. Beyond the phonon modes the optical conductivity is explained by polaronic excitations out of a bound state. ESR techniques yield detailed informations on the (H,T ) phase diagram and reveal a broadening of the linewidth which can be modeled in terms of activated polaron hopping.

State diagram of Pr-Bi system

International Nuclear Information System (INIS)

Abulkhaev, V.L.; Ganiev, I.N.

1994-01-01

By means of thermal differential analysis, X-ray and microstructural analysis the state diagram of Pr-Bi system was studied. Following intermetallic compounds were defined in the system: Pr 2 Bi, Pr 5 Bi 3 , Pr 4 Bi 3 , Pr Bi, PrBi 2 , Pr 2 Bi, Pr 5 Bi 3 , Pr 4 Bi 3 and PrBi 2 . The data analysis on Ln-Bi diagram allowed to determine the regularity of change of properties of intermetallic compounds in the line of rare earth elements of cerium subgroup.

Optical characterization of Pr3+-doped yttria-stabilized zirconia single crystals

International Nuclear Information System (INIS)

Savoini, B.; Munoz Santiuste, J.E.; Gonzalez, R.

1997-01-01

The optical absorption and fluorescence of Pr 3+ ions in yttria-stabilized zirconia single crystals are investigated. Fluorescence emissions from the 1 D 2 level are clearly dominant and low intensity emission lines from the 3 P 0 and 1 G 4 states are also observed. Analysis with the Judd-Ofelt theory of the absorption intensities has been made assuming that only ∼40% of the praseodymium ions contribute to the optical absorption bands. Quantum efficiency values of η( 3 P 0 )∼0.2 and η( 1 D 2 )∼ 1 are obtained at room temperature. 1 D 2 fluorescence quenching has been observed in heavily-doped samples due to cross relaxation processes among neighboring Pr 3+ ions. Analysis using the Inokuti-Hirayama model shows that electric dipole-dipole interactions are mainly responsible for the quenching effect. Pr 3+ ions are present in seven and sixfold configurations with a statistical distribution. The energy position of the 4f5d configuration is very different for each center. The fluorescence dynamics is explained by a mechanism involving thermally assisted population of the 3 P 1,2 + 1 I 6 upper levels and fast relaxation to the 1 D 2 level via states of the excited 4f5d configuration. copyright 1997 The American Physical Society

Electronic structures of PrBa2Cu3O7, Pr2Ba4Cu7O15-y(y=0,1), and PrBa2Cu4O8 based on LSDA+U method

International Nuclear Information System (INIS)

Tavana, A.; Shirazi, M.; Akhavan, M.

2009-01-01

The electronic structures of PrBa 2 Cu 3 O 7 (Pr123), Pr 2 Ba 4 Cu 7 O 15-y (Pr247), and PrBa 2 Cu 4 O 8 (Pr124) cuprates have been obtained using density-functional theory in the local spin density approximation plus onsite Coulomb interaction (LSDA+U). Onsite Hubbard correlation, U, has been considered for Pr-f and Cu-d orbitals and the effects of considering these correlation corrections on the Pr-O hybridizations have been inspected. Results imply that the Pr ionization state in Pr123 system is constituted from two different configurations, and the energy of the f states in these two configurations has an important role in superconductivity properties of the system. Our calculations also show that in both Pr124 and Pr247 systems, suppression of superconductivity is weaker than that in the Pr123 system. This occurs due to the weaker Pr-O bond in both Pr124 and Pr247 systems. The role of the double chain and single chain on the conduction properties of these compounds has been investigated. We have also studied the effect of oxygen deficiency in Pr247 system, which seems to revive superconductivity in this system. Investigating the hole carriers in the CuO 2 plane shows a correlation between superconductivity suppression and hole decrement in the planes. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Comparison of the luminescent properties of Lu3Al5O12:Pr crystals and films under synchrotron radiation excitation

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Zorenko, T.; Voznyak, T.; Nizankovskiy, S.

2016-01-01

The work is dedicated to comparative investigation of the luminescent properties of Lu 3 Al 5 O 12 :Pr(LuAG:Pr) single crystals and single crystalline films using excitation by synchrotron radiation with an energy of 3.7–25 eV in the exciton range of LuAG host. We have found that the differences in the excitation spectra and luminescence decay kinetics of LuAG:Pr crystals and films are caused by involving the LuAl antisite defects and oxygen vacancies in the crystals and Pb 2+ flux related dopants in the films in the excitation processes of the Pr 3+ luminescence. Taking into account these differences, we have determined the energy structure of the Pr 3+ ions in LuAG host and estimated the differences in the energies of creation of excitons bound with the isolated Pr 3+ ions in LuAG:Pr films and the dipole Pr–LuAl antisite defect centers in the crystal counterpart. - Highlights: • Comparison of the luminescent properties of LuAG:Pr single crystals and films. • Superposition of the Pr 3+ and defect centers luminescence of LuAG:Pr crystal. • Different creation energies of an excitons bound with the Pr 3+ in LuAG:Pr crystals and films. • More faster decay kinetics of the Pr 3+ luminescence in LuAG:Pr films. • Low content of slow emission component in LuAG:Pr films.

Association of body mass index with ER, PR and 14-3-3σ expression in tumor and stroma of type I and type II endometrial carcinoma.

Science.gov (United States)

Peevey, Joseph F; Seagle, Brandon-Luke L; Maniar, Kruti P; Kim, J Julie

2017-06-27

Obesity is a prominent risk factor for endometrial cancer (EC) and can impede on surgical and hormonal treatments. Markers of EC, estrogen receptor (ER), progesterone receptor (PR), phospho(Ser473)-AKT (pAKT) and 14-3-3 sigma (14-3-3σ) were measured in EC tissues in both the tumor and stroma and grouped by body mass index (BMI). Immunohistochemical scoring of 82 cases of Type 1 and Type II EC tissues revealed a significantly increased tumor expression of ER, PR and 14-3-3σ in women with Type I (BMI PR and 14-3-3σ in the tumor epithelium was significantly higher in Type I than Type II. In particular, Type I EC exhibited significantly increased levels of only PR from patients with BMI > 40 compared to BMI PR, PIK3CA, PTEN and SFN (gene for 14-3-3σ) confirmed increased PR expression in EC of obese women. In conclusion, ER, PR and 14-3-3σ are differentially regulated in Type I compared to Type II EC while PR is dysregulated in obese women with Type I EC. These findings have potential implications for efficacy of progestin treatment in obese women.

Optical investigation of the valency of Pr in Y1-xPrxBa2Cu3O7-δ

International Nuclear Information System (INIS)

Kircher, J.; Cardona, M.; Gopalan, S.; Habermeier, H.; Fuchs, D.

1991-01-01

We have investigated the dependence of the visible-ultraviolet dielectric function of Y 1-x Pr x Ba 2 Cu 3 O 7 on the Pr content x using rotating analyzer ellipsometry. Based on recently published band-structure calculations, we believe that the valency of Pr can be deduced from the optical properties in this spectral region. Interband transitions should shift to higher energies for Pr 4+ and to lower energies for Pr 3+ when compared to the optical spectra of YBa 2 Cu 3 O 7 . In the case of tetravalent Pr ions, transitions into unoccupied Pr 5d levels should be observable. Since the experimental energies for interband transitions shift down with increasing x and no additional structure can be seen, we conclude that Pr is trivalent in Y 1-x Pr x Ba 2 Cu 3 O 7

Simultaneous quantification of T4, T3, rT3, 3,5-T2 and 3,3'-T2 in larval zebrafish (Danio rerio) as a model to study exposure to polychlorinated biphenyls.

Science.gov (United States)

Chen, Xiaopeng; Walter, Kyla M; Miller, Galen W; Lein, Pamela J; Puschner, Birgit

2018-06-01

Environmental toxicants that interfere with thyroid hormone (TH) signaling can impact growth and development in animals and humans. Zebrafish represent a model to study chemically induced TH disruption, prompting the need for sensitive detection of THs. Simultaneous quantification of 3,3',5-triiodo-l-thyronine (T3), thyroxine (T4), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (3,5-T2) and 3,3'-diiodo-l-thyronine (3,3'-T2) in zebrafish larvae was achieved by ultra-performance liquid chromatography-tandem mass spectrometry in positive ion mode. Solid-phase extraction with SampliQ cartridges and derivatization with 3 m hydrochloric acid in n-butanol reduced matrix effects. Derivatized compounds were separated on an Acquity UPLC BEH C 18 column with mobile phases consisting of 0.1% acetic acid in deionized water and 0.1% acetic acid in methanol. The limits of detection ranged from 0.5 to 0.6 pg injected on column. The method was validated by evaluating recovery (77.1-117.2%), accuracy (87.3-123.9%) and precision (0.5-12.4%) using diluted homogenized zebrafish embryos spiked with all target compounds. This method was then applied to zebrafish larvae collected after 114 h of exposure to polychlorinated biphenyls (PCBs), including PCB 28, PCB 66 and PCB 95, or the technical mixture Aroclor 1254. Exposure to PCB 28 and PCB 95 increased the T4:T3 ratio and decreased the T3:rT3 ratio, demonstrating that this method can effectively detect PCB-induced alterations in THs. Copyright © 2018 John Wiley & Sons, Ltd.

Spectral analysis of Pr{sup 3+} doped germanate glasses modified by BaO and BaF{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Pisarska, Joanna, E-mail: joanna.pisarska@us.edu.pl [University of Silesia, Institute of Chemistry, Szkolna 9 Street, 40-007 Katowice (Poland); Pisarski, Wojciech A. [University of Silesia, Institute of Chemistry, Szkolna 9 Street, 40-007 Katowice (Poland); Dorosz, Dominik; Dorosz, Jan [Bialystok University of Technology, Faculty of Electrical Engineering, Wiejska 45D Street, 15-351 Bialystok (Poland)

2016-03-15

Luminescence properties of Pr{sup 3+} ions in germanate glasses modified by BaF{sub 2} were investigated. Several luminescence bands originating to transitions from the {sup 3}P{sub 0} state to the lower-lying states of Pr{sup 3+} were registered under 450 nm excitation. The spectral analysis suggests that the positions of luminescence bands and their relative intensities are changed significantly with BaF{sub 2} content. The relative integrated luminescence intensities of {sup 3}P{sub 0}→{sup 3}H{sub 4} transition (blue) to the {sup 3}P{sub 0}→{sup 3}F{sub 2} transition (red) of Pr{sup 3+} ions strongly depend on fluoride modifier BaF{sub 2} in glass composition. The luminescence bands of Pr{sup 3+} ions are shifted to shorter wavelengths with increasing BaF{sub 2} content. - Highlights: • Praseodymium doped lead-free germanate glasses modified by BaF{sub 2} were prepared. • Emission spectra correspond to transitions from {sup 3}P{sub 0} state to lower-lying states of Pr{sup 3+}. • The relative emission band intensities of Pr{sup 3+} depend strongly on BaF{sub 2} content. • Emission bands of Pr{sup 3+} are shifted to shorter wavelengths with increasing BaF{sub 2} content.

Apparent molar volumes and apparent molar heat capacities of Pr(NO{sub 3}){sub 3}(aq), Gd(NO{sub 3}){sub 3}(aq), Ho(NO{sub 3}){sub 3}(aq), and Y(NO{sub 3}){sub 3}(aq) at T (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa

Energy Technology Data Exchange (ETDEWEB)

Hakin, Andrew W. [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada)]. E-mail: hakin@uleth.ca; Liu Jinlian [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Erickson, Kristy [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Munoz, Julie-Vanessa [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Rard, Joseph A. [Energy and Environment Directorate, Lawrence Livermore National Laboratory, University of California, Livermore, CA 94550 (United States)

2005-02-01

Relative densities and relative massic heat capacities have been measured for acidified solutions of Y(NO{sub 3}){sub 3}(aq), Pr(NO{sub 3}){sub 3}(aq), and Gd(NO{sub 3}){sub 3}(aq) at T = (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa. In addition, relative densities and massic heat capacities have been measured at the same temperatures and pressure for Y(NO{sub 3}){sub 3}(aq) and Ho(NO{sub 3}){sub 3}(aq) solutions without excess acid (n.b. measurements at T = 328.15 K for Ho(NO{sub 3}){sub 3}(aq) were not performed due to the limited volume of solution available). Apparent molar volumes and apparent molar heat capacities for the aqueous salt solutions have been calculated from the experimental apparent molar properties of the acidified solutions using Young's rule, whereas the apparent molar properties of the solutions without excess acid were calculated directly from the measured densities and massic heat capacities. The two sets of data for the Y(NO{sub 3}){sub 3}(aq) systems provide a check of the internal consistency of the Young's rule approach we have utilised. The concentration dependences of the apparent molar volumes and heat capacities of the aqueous salt solutions have been modelled at each investigated temperature using the Pitzer ion interaction equations to yield apparent molar properties at infinite dilution. Complex formation within the aqueous rare earth nitrate systems is discussed qualitatively by probing the concentration dependence of apparent molar volumes and heat capacities. In spite of the complex formation in the aqueous rare earth nitrate systems, there is a high degree of self-consistency between the apparent molar volumes and heat capacities at infinite dilution reported in this manuscript and those previously reported for aqueous rare earth perchlorates.

PrB{sub 7}{sup -}. A praseodymium-doped boron cluster with a Pr{sup II} center coordinated by a doubly aromatic planar η{sup 7}-B{sub 7}{sup 3-} ligand

Energy Technology Data Exchange (ETDEWEB)

Chen, Teng-Teng; Jian, Tian; Wang, Lai-Sheng [Department of Chemistry, Brown University, Providence, RI (United States); Li, Wan-Lu; Chen, Xin; Li, Jun [Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing (China)

2017-06-06

The structure and bonding of a Pr-doped boron cluster (PrB{sub 7}{sup -}) are investigated using photoelectron spectroscopy and quantum chemistry. The adiabatic electron detachment energy of PrB{sub 7}{sup -} is found to be low [1.47(8) eV]. A large energy gap is observed between the first and second detachment features, indicating a highly stable neutral PrB{sub 7}. Global minimum searches and comparison between experiment and theory show that PrB{sub 7}{sup -} has a half-sandwich structure with C{sub 6v} symmetry. Chemical bonding analyses show that PrB{sub 7}{sup -} can be viewed as a Pr{sup II}[η{sup 7}-B{sub 7}{sup 3-}] complex with three unpaired electrons, corresponding to a Pr (4f{sup 2}6s{sup 1}) open-shell configuration. Upon detachment of the 6s electron, the neutral PrB{sub 7} cluster is a highly stable Pr{sup III}[η{sup 7}-B{sub 7}{sup 3-}] complex with Pr in its favorite +3 oxidation state. The B{sub 7}{sup 3-} ligand is found to be highly stable and doubly aromatic with six delocalized π and six delocalized σ electrons and should exist for a series of lanthanide M{sup III}[η{sup 7}-B{sub 7}{sup 3-}] complexes. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Pr3 + -doped GeSx-based glasses for fiber amplifiers at 1.3 µm

Science.gov (United States)

Simons, D. R.; Faber, A. J.; de Waal, H.

1995-03-01

The photoluminescence properties of Pr3+ -doped GeS x -based glasses are studied and compared with those of other sulfide and fluoride glasses. The possibility of highly pump-power-efficient fiber amplifiers based on these GeSx-containing glasses in the telecommunications window at 1.3 mu m is discussed.

PR-957, a selective inhibitor of immunoproteasome subunit low-MW polypeptide 7, attenuates experimental autoimmune neuritis by suppressing Th17-cell differentiation and regulating cytokine production.

Science.gov (United States)

Liu, Haijie; Wan, Chunxiao; Ding, Yanan; Han, Ranran; He, Yating; Xiao, Jinting; Hao, Junwei

2017-04-01

Experimental autoimmune neuritis (EAN) is a CD4 + T-cell-mediated autoimmune inflammatory demyelinating disease of the peripheral nervous system. It has been replicated in an animal model of human inflammatory demyelinating polyradiculoneuropathy, Guillain-Barré syndrome. In this study, we evaluated the therapeutic efficacy of a selective inhibitor of the immunoproteasome subunit, low-MW polypeptide 7 (PR-957) in rats with EAN. Our results showed that PR-957 significantly delayed onset day, reduced severity and shortened duration of EAN, and alleviated demyelination and inflammatory infiltration in sciatic nerves. In addition to significantly regulating expression of the cytokine profile, PR-957 treatment down-regulated the proportion of proinflammatory T-helper (T h )17 cells in sciatic nerves and spleens of rats with EAN. Data presented show the role of PR-957 in the signal transducer and activator of transcription 3 (STAT3) pathway. PR-957 not only decreased expression of IL-6 and IL-23 but also led to down-regulation of STAT3 phosphorylation in CD4 + T cells. Regulation of the STAT3 pathway led to a reduction in retinoid-related orphan nuclear receptor γ t and IL-17 production. Furthermore, reduction of STAT3 phosphorylation may have directly suppressed T h 17-cell differentiation. Therefore, our study demonstrates that PR-957 could potently alleviate inflammation in rats with EAN and that it may be a likely candidate for treating Guillain-Barré syndrome.-Liu, H., Wan, C., Ding, Y., Han, R., He, Y., Xiao, J., Hao, J. PR-957, a selective inhibitor of immunoproteasome subunit low-MW polypeptide 7, attenuates experimental autoimmune neuritis by suppressing T h 17-cell differentiation and regulating cytokine production. © FASEB.

Luminescence of (Ca,Sr)3(VO4)2: Pr3+, Eu3+ phosphor for use in CuPc-based solar cells and white light-emitting diodes

International Nuclear Information System (INIS)

Lin, Han-Yu; Chang, Wei-Fu; Chu, Sheng-Yuan

2013-01-01

The purpose of this study is to enhance the red emission intensity and expand the blue excitation band of a (Ca,Sr) 2.82 (VO 4 ) 2 :0.12Eu 3+ phosphor for use in copper phthalocyanine (CuPc)-based solar cells and white light-emitting diodes. It was found that substitution of 3% Sr 2+ replacing Ca 2+ enhanced red emission intensity of Ca 2.82 (VO 4 ) 2 :0.12Eu 3+ by 14% under 465-nm by excitation. The Pr 3+ co-doping effect was realized when blue excitation intensity of (Ca 0.97 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.12Eu 3+ , located in the weakest absorption of CuPc, was improved by 126% with the addition of 0.6 mol% Pr 3+ . The absorption spectrum of CuPc/optimized (Ca 0.9668 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.006Pr 3+ , 0.12Eu 3+ mixtures provided evidence that the (Ca 0.9668 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.006Pr 3+ , 0.12Eu 3+ phosphor could increase the efficiency of incident photons on CuPc-based solar cells. Moreover, the good temperature stability of emission intensity and chromaticity of (Ca 0.9668 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.006Pr 3+ , 0.12Eu 3+ indicated a potential for this phosphor to be applied on the white light-emitting diodes. - Highlights: ► Substitution of 3% Sr 2+ replacing Ca 2+ enhanced red emission intensity of Ca 2.82 (VO 4 ) 2 :0.12Eu 3+ by 14% under 465 nm by excitation. ► Addition of 0.6 mol% Pr 3+ enhanced blue excitation intensity of (Ca 0.97 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.12Eu 3+ , located in the weakest absorption of CuPc, by 126%. ► According to absorption measurements of CuPc/optimized (Ca 0.9668 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.006Pr 3+ , 0.12Eu 3+ mixtures for the first time, the feasibility of our phosphor to assist CuPc in converting blue-wavelength photons was proved. ► High temperature stability of emission intensity and chromaticity of (Ca 0.9668 Sr 0.03 ) 2.82 (VO 4 ) 2 :0.006Pr 3+ , 0.12Eu 3+ indicated our phosphor is acceptable for WLED applications.

Crystal structure of the compounds R8Ga3Co (R=Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm)

International Nuclear Information System (INIS)

Grin', Yu.N.; Sichevich, O.M.; Gladyshevskij, R.E.; Yarmolyuk, Ya.P.

1984-01-01

The crystal structure of Pr 8 Ga 3 Co compounds is studied by the method of monocrystal (autodiffractometer, MoKsub(α)): space group P6 3 mc, a=10.489, c=6.910 A, Z=2. Coordination numbers of atoms are 11-14 for Pr, 11 for Ga, 7 for Co. The shortest interatomic distances are 3.365 for Pr-Pr, 3.047 for Pr-Ga, 2.75 A for Pr-Co. Pr 3 Ga 3 Co structure is akin to structures of R 2 In compounds (Ni 2 In type) and R 2 Ga (Cl 2 Pb type). Isostructural compounds form in systems of other rare earth metals with gallium and cobalt

Structural, optical and spectroscopical investigations into rare-earths perowskites RGaO3 (R=La, Pr, Nd) and NdBa-2Cu3O7-δ

International Nuclear Information System (INIS)

Marti, W.

1995-07-01

In this work I was engaged in rare-earth perovskites. Primarily I investigated the structure of the rare-earth gallates RGaO 3 (R=La, Pr, Nd) as a function of the temperature by means of neutron diffraction and x-ray diffraction. As the high-T c superconductors these compounds belong to the family of the perovskites, they are ferroelastic and centro-symmetric. Because of the lanthanide-contraction all lattice constants and distortion parameters change systematically. The rare-earth-gallates RGaO 3 (R=La, Pr, Nd) are promising substrates for epitaxy of high-T c superconductors like RBa 2 Cu 3 OO 7-δ because of their structure parameters and expansion coefficients. I succeeded in producing plane-parallel single-domain crystals by means of uniaxial stress. The first order phase transition was observable only in LaGaO 3 . A structurally phase transition from orthorhombic to rhombohedral symmetry (high-temperature phase) occurs at 423 K. The hysteresis of the phase transition temperature of about 1.5 K was measured with single-domain crystals by means of neutron diffraction and polarized light microscopy. In NdGaO 3 we determined the long-range, three-dimensional, antiferromagnetic ordering of the Nd 3+ -ions below the ordering temperature at T N =0.97 K by means of magnetic neutron diffraction. The spin configuration could be described by a (--c z )-mode. Measurements of the magnetic susceptibility confirm the easy direction of magnetization to be the c-axis. Below 300mK an additional nuclear spin polarization due to the hyperfine-interaction appears parallel to the electronic spins, which amounts to 70% at 10mK. Further I investigated the optical properties of the rare-earth gallates. The birefringence of plane-parallel, polished single-domain crystals with thickness up to 300 μm was measured by means of orthoscopy and conoscopy. (author) figs., tabs., refs

Optical spectra and analysis of Pr3+ in β-NaYF4

International Nuclear Information System (INIS)

Martin, N.; Boutinaud, P.; Mahiou, R.; Cousseins, J.C.

1998-01-01

We report a spectroscopic investigation of β-NaYF 4 :Pr 3+ . In order to study the upconversion properties of this system we determined the Stark energy level of different multiplets from luminescence spectra using polycrystalline samples with several concentrations at temperatures between 15 and 300 K. We correlate the luminescence and structural description and confirm the presence of three sites for the rare-earth ions in this material. Selective excitation is used to assign the self energy levels for each Pr 3+ ion in the three sites. (orig.)

[Pr2(pdc3(Hpdc(H2O4]n·n(H3hp·8n(H2O, a One-Dimensional Coordination Polymer Containing PrO6N3 Tri-Capped Trigonal Prisms and PrO8N Mono-Capped Square Anti-Prisms (H2pdc = Pyridine 2,6-Dicarboxylic Acid, C7H5NO4; 3hp = 3-Hydroxy Pyridine, C5H5NO

Directory of Open Access Journals (Sweden)

Shahzad Sharif

2012-08-01

Full Text Available The synthesis, structure and some properties of the one-dimensional coordination polymer, [Pr2(pdc3(Hpdc]n·n(H3hp·8n(H2O, (H2pdc = pyridine 2,6-dicarboxylic acid, C7H5NO4; 3hp = 3-hydroxypyridine, C5H5NO are described. One of the Pr3+ ions is coordinated by two O,N,O-tridentate pdc2− ligands and one tridentate Hpdc− anion to generate a fairly regular PrO6N3 tri-capped trigonal prism, with the N atoms acting as the caps. The second Pr3+ ion is coordinated by one tridentate pdc2− dianion, four water molecules and two monodentate bridging pdc2− ligands to result in a PrO8N coordination polyhedron that approximates to a mono-capped square-anti-prism. The ligands bridge the metal-atom nodes into a chain, which extends in the [100] direction. The H3hp+ cation and uncoordinated water molecules occupy the inter-chain regions and an N–HLO and numerous O–HLO hydrogen bonds consolidate the structure. The H3hp+ species appears to intercalate between pendant pdc rings to consolidate the polymeric structure. Crystal data: 1 (C33H43N5O29Pr2, Mr = 1255.54, triclinic,  (No. 2, Z = 2, a = 13.2567(1 Å, b = 13.6304(2 Å, c = 13.6409(2 Å, α = 89.695(1°, β = 63.049(1°, γ = 86.105(1°, V = 2191.16(5 Å3, R(F = 0.033, wR(F2 = 0.084.

Pr3+-doped GeSx-based glasses for fiber amplifiers at 1.3 mm

NARCIS (Netherlands)

Simons, D.R.; Faber, A.J.; Waal, de H.

1995-01-01

The luminescence of Pr3+-doped GeSx-based glasses were studied and compared with those of other sulfide and fluoride glasses. The possibility of highly pump-power-efficient fiber amplifiers based on these GeSx-contg. glasses in the telecommunications window at 1.3 mm is discussed. [on SciFinder (R)

Enhancement in magnetic and dielectric properties of La and Pr co substituted BiFeO3

International Nuclear Information System (INIS)

Srivastava, Amit; Singh, H.K.; Awana, V.P.S.; Srivastava, O.N.

2013-01-01

Highlights: ► Significant enhancement in magnetization of BiFeO 3 is found on La and Pr co substitution. ► It is correlated with structural phase transformation and nanosized crystallites. ► Dielectric losses strongly diminish with La and Pr co substitution. -- Abstract: This report underlines the systematic studies of crystalline structure, magnetic and ferroelectric properties of polycrystalline Bi 1−x−y La x Pr y FeO 3 ceramic samples, in which x changes continuously from 0 to 0.2 for y = 0 and y from 0 to 0.2 for x = 0.2. X-ray diffraction (XRD) patterns revealed that La and Pr substitution at Bi site in the ceramic eliminates the usual impurity phases completely. Rietveld refinement of the XRD patterns shows that the crystal structure changes gradually from Rhombohedral (R3c) to Orthorhombic (pbnm) with increasing La and Pr concentration. This transition has significant effects on the multiferroic properties of Bi 1−x−y La x Pr y FeO 3 ceramics. Substantial enhancement in magnetization of Bi 1−x−y La x Pr y FeO 3 has been observed and this is found to be correlated with the evolution of structural phase change with doping of Pr in samples having lanthanum concentration of x = 0.2. This leads to the suppression of helical spin order. However, the enhancement in magnetic behavior also takes place due to nanocrystallite nature of Bi 1−x−y La x Pr y FeO 3 (x = 0.2, y = 0.05–0.2). For the nanocrystallites having sizes lower than 62 nm, which is the period of spin cycloid, this spin configuration will get destroyed resulting in the enhancement of magnetization. The studies of microstructures employing SEM and TEM revealed that Bi 1−x−y La x Pr y FeO 3 consists of nano size grained microstructures. It is also found that dielectric constant and dielectric loss get improved by La and Pr co-substitution. The dielectric constant for x = 0.0, y = 0.0 is 81 which changes to 354 for x = 0.2, y = 0.15 at 100 Hz. Dielectric losses are strongly

The Pr 2O 3/Si(0 0 1) interface studied by synchrotron radiation photo-electron spectroscopy

Science.gov (United States)

Schmeißer, D.; Müssig, H.-J.

2003-10-01

Pr 2O 3 is currently under consideration as a potential replacement for SiO 2 as the gate-dielectric material for sub-0.1 μm complementary metal-oxide-semiconductor (CMOS) technology. We studied the Pr 2O 3/Si(0 0 1) interface by a non-destructive depth profiling using synchrotron radiation photoelectron spectroscopy. Our data suggests that there is no silicide formation at the interface. Based on reported results, a chemical reactive interface exists, consisting of a mixed Si-Pr oxide such as (Pr 2O 3) x(SiO 2) 1- x, i.e. as a silicate phase with variable silicon content. This pseudo-binary alloy at the interface offers large flexibility toward successful integration of Pr 2O 3 into future CMOS technologies.

Synthesis and photoluminescence properties of Eu{sup 3+}, Sm{sup 3+} and Pr{sup 3+} doped Ca{sub 2}ZnWO{sub 6} phosphors for phosphor converted LED

Energy Technology Data Exchange (ETDEWEB)

Dabre, K.V. [Department of Physics, Arts, Commerce and Science College, Koradi, Nagpur-441111, Maharashtra (India); Dhoble, S.J., E-mail: sjdhoble@rediffmail.com [Department of Physics, R.T.M. Nagpur University, Nagpur-440033, Maharashtra (India)

2014-06-01

In this work, we report on the synthesis and photoluminescence (PL) properties of rare earth (Eu{sup 3+}, Sm{sup 3+} and Pr{sup 3+}) doped double perovskite tungstate Ca{sub 2}ZnWO{sub 6} phosphor. The phosphors were synthesized by two step modified solid state method. Phase purity and formation of phosphor were confirmed by XRD technique. PL spectra of Eu{sup 3+}, Sm{sup 3+} and Pr{sup 3+} doped phosphor show intense emission peaks in red region at 615, 604 and 650 nm respectively, upon the visible excitation of 466 nm (Eu{sup 3+}), 410 nm (Sm{sup 3+}) and 491 nm (Pr{sup 3+}). The CIE coordinates of the phosphors are in the yellow (Sm{sup 3+} doped sample) and orange (Eu{sup 3+} and Pr{sup 3+} doped sample) regions near the edge of color space which confirms their applicability in LEDs. -- Highlights: •Eu{sup 3+}, Sm{sup 3+} and Pr{sup 3+} doped and undoped samples of Ca{sub 2}ZnWO{sub 6} phosphor synthesized by Solid state method. •The phosphors have intense excitation in violet and blue region of visible spectrum. •Phosphors show intense emission peaks in red region. •CIE coordinates of phosphors are lie in yellow (Sm{sup 3+} doped phosphor) and orange (Eu{sup 3+} and Pr{sup 3+} doped phosphor) region near to edge of color space.

Characterization and optical properties of Pr2O3-doped ...

Indian Academy of Sciences (India)

2017-06-09

Jun 9, 2017 ... Pr3+ doped molybdenum lead-borate glasses with the chemical ... Thermal, optical and structural analyses are carried out using DSC, UV and FTIR spectra. ... energy band gap (Egopt), of these glasses have been determined.

Alternative crystal field parameters for rare-earth ions obtained from various techniques: IV. Comparative analysis of crystal field parameters obtained from inelastic neutron scattering and related studies of RE ions (RE = Er{sup 3+}, Ho{sup 3+}, Nd{sup 3+}, Pr{sup 3+}) in REBa{sub 2}Cu{sub 3}O{sub 7-{delta}} high-T{sub c} superconductors

Energy Technology Data Exchange (ETDEWEB)

Rudowicz, Czeslaw, E-mail: crudowicz@zut.edu.pl [Modeling in Spectroscopy Group, Institute of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology, Szczecin, al. Piastow 48, 70-311 Szczecin (Poland); Lewandowska, Monika [Modeling in Spectroscopy Group, Institute of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology, Szczecin, al. Piastow 48, 70-311 Szczecin (Poland)

2012-11-05

Highlights: Black-Right-Pointing-Pointer Orthorhombic crystal field parameters (CFPs) for RE3{sup +} in REBa{sub 2}Cu{sub 3}O{sub 7-{delta}} studied. Black-Right-Pointing-Pointer Comparative analysis of CFP sets for Er{sup 3+}, Ho{sup 3+}, Nd{sup 3+}, and Pr{sup 3+} ions performed. Black-Right-Pointing-Pointer Aspects related to CFP standardization considered. Black-Right-Pointing-Pointer Several problems identified due to comparative CFP analysis clarified. Black-Right-Pointing-Pointer Correct comparison of different CFP sets must be based on standardization. - Abstract: This is fourth paper in a series devoted to reanalysis of the non-standard and standard crystal-field (CF) parameter (CFP) sets obtained from various experimental techniques and theoretical models for trivalent rare-earth (RE) ions in high-critical-temperature (high-T{sub c}) superconductors and related systems. In this paper the experimental orthorhombic CFPs, obtained mostly by inelastic neutron scattering techniques and to a lesser extent by magnetic susceptibility and specific heat measurements as well as the respective theoretical CFPs for Er{sup 3+}, Ho{sup 3+}, Nd{sup 3+}, and Pr{sup 3+} ions in REBa{sub 2}Cu{sub 3}O{sub 7-{delta}} compounds, are considered. Several problems identified due to the comparative CFP analysis: (i) confusing notations used for operators and CFPs, (ii) different scaling factors and units used for CFPs, and (iii) lack of clear definitions of the axis systems used to express CFPs, were clarified. For each ion studied the available experimental and theoretical CFP sets are analyzed, standardized, and presented in a unified way. The large number of CFP sets prevents calculation of the five additional alternative sets for each originally reported CFP set. Instead, the alternative CFP sets are determined using the package CST for an average set calculated for selected compatible sets for each ion. These alternative CFP sets may be utilized in the multiple correlated

Electronic and magnetic properties of quasi-skutterudite PrCo2Ga8 compound

Science.gov (United States)

Ogunbunmi, Michael O.; Sondezi, Buyisiwe M.; Nair, Harikrishnan S.; Strydom, André M.

2018-05-01

PrCo2Ga8 is an orthorhombic quasi-skutterudite type compound which crystallizes in the CaCo2Al8 structure type, with space group Pbam (No. 55). The Pr3+ ion has a site symmetry of Cs which predicts a crystal electric field (CEF) level splitting into 9 singlets for J = 4. However, a phase transition at Tm = 1.28 K is observed in electrical resistivity and specific heat results and is reported in this paper. The electrical resistivity shows an upturn below Tm due to the superzone-gap formation. This transition is tuneable in fields and is suppressed to lower temperatures with applied magnetic fields. The electronic specific heat Cp(T) / T increases below Tm and reaches a value of 7.37 J/(mol K2) at 0.4 K. The Sommerfeld coefficient, γ extracted from the low temperature analysis of C4f(T) / T is 637 mJ/(mol K2) indicating a possible mass enhancement of the quasiparticles. The calculated entropy value of 3.05 J/(mol K) is recovered around Tm exhibiting almost 53% of Rln2, where R is the universal gas constant. Magnetic susceptibility results obeys the Curie-Weiss law for data above 100 K with an estimated effective magnetic moment, μeff = 3.37 μB/Pr and Weiss temperature, θp = -124 K.

Pr2Fe14B/α-Fe nanocomposites for thermal applications

International Nuclear Information System (INIS)

Silva, Suelanny Carvalho da

2012-01-01

In this work, Pr x Fe 94 - x B 6 (x = 6, 8, 10 and 12) nanostructured powders were prepared by a combination of hydrogenation, disproportionation, desorption and recombination (HDDR) process with high energy milling applied to the mixture of an as-cast alloy (Pr 14 Fe 80 B 6 ) and α-Fe. The produced nanoparticles showed magnetic properties comparable to those reported in hyperthermia studies. The optimal time to obtain the magnetic nanoparticles is 5 hours (at 900 rpm). It was verified that longer milling times cause an increase in carbon percentage on the particles. The carbon is derived from oleic acid added as a surfactant in the milling step. The nanocomposites exhibit coercive force ranging from 80 Oe (6.5 kAm -1 ) to 170 Oe (13.5 kAm -1 ) and magnetic moments in the range of 81 129 Am2kg -1 . From the X-ray diffraction analyses, only two phases were found in all samples: α-Fe and the magnetic phase Pr 2 Fe 14 B. Individual nanoparticles with diameter of about 20 nm were verified. The samples studied presented heating when exposed to an alternating magnetic field (f = 222 kHz e H max ∼3.7 kAm -1 ) comparable to reported in literature. Temperature variations (ΔT) of the powders were: 51 K for Pr 6 Fe 88 B 6 , 41 K for Pr 8 Fe 86 B 6 , 38 K for Pr 10 Fe 8 4 B 6 and T = 34 K for Pr 12 Fe 82 B 6 . The specific absorption rates (SARs) of the powders were 201 Wkg -1 for Pr 6 Fe 88 B 6 composition, 158 Wkg -1 on the composition Pr 8 Fe 86 B 6 , and 114 Wkg -1 for Pr 10 Fe 84 B 6 and Pr 12 Fe 82 B 6 compositions. (author)

Incommensurate magnetism in non-superconducting PrBa2Cu3O6.92

DEFF Research Database (Denmark)

Boothroyd, A.T.; Hill, J.P.; McMorrow, D.F.

1999-01-01

We report the discovery of incommensurate magnetic order in non-superconducting single crystals PrBa2Cu3O6.92. Resonant X-ray magnetic scattering at the Pr L-II and L-III edges and high resolution neutron diffraction were used to characterise the magnetic order on the different magnetic sublattices...

Microstructural, magnetic and transport properties of La{sub 0.5}Pr{sub 0.2}Pb{sub 0.3-x}Sr{sub x}MnO{sub 3} manganites

Energy Technology Data Exchange (ETDEWEB)

Craus, M.-L., E-mail: kraus@nf.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Institute of Research and Development for Technical Physics, Iasi (Romania); Islamov, A.Kh., E-mail: islamov@nf.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Laboratory of Advanced Research of Membrane Proteins, Moscow Institute of Physics and Technology, Dolgoprudniy (Russian Federation); Anitas, E.M., E-mail: anitas@theor.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Cornei, N., E-mail: ncornei@uaic.ro [“Al. I. Cuza” University, Chemistry Department, Iasi (Romania); Luca, D., E-mail: dluca@tuiasi.ro [“Gh. Asachi” Technical University, Faculty of Materials Science and Engineering, Iasi (Romania)

2014-04-01

Highlights: • We synthesized a series of pure La{sub 0.5}Pr{sub 0.2}Pb{sub 0.3−x}Sr{sub x}MnO{sub 3} manganites using ceramic technology. • The crystalline structure depends on the Sr concentration. • Small-angle neutron scattering reveals the presence of magnetic nanodomains at temperatures higher than Curie temperature. • The crystalline structure, the shape and the concentration of magnetic nanodomains are correlated with transport phenomena. - Abstract: The most interesting and studied materials for practical applications of colossal magnetorsistance effect are rare earth manganites with general formula RMnO{sub 3} (where R is a rare/alkaline earth element). The coexisting of competing phases in manganites, such as metallic ferromagnetic, charge ordered, antiferromagnetic insulating and ferromagnetic insulating phases, determines an important change of magnetic and transport properties with the microstructure. In this paper, we report on the correlations between microstructural, magnetic and transport properties at temperatures ranging from 263 to 343 K of La{sub 0.5}Pr{sub 0.2}Pb{sub 0.3-x}Sr{sub x}MnO{sub 3} manganites synthesized by ceramic technology. The microstructure is studied using X-ray diffraction (XRD), small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) at Sr concentrations x=0.00,0.05,0.15 and 0.20. SAXS and SANS data show the formation of magnetic nanodomains in the mosaic blocks, at temperatures higher than Curie temperature T{sub C}. SANS data reveal the shape and concentration of magnetic nanodomains, and their dependency on temperature. The La{sub 0.5}Pr{sub 0.2}Pb{sub 0.3-x}Sr{sub x}MnO{sub 3} manganites crystallize as cubic structure Pm3{sup ¯}m (x=0.00 and x=0.05) or as rhombohedral structure R3{sup ¯}c (x=0.15 and x=0.20). We found that transport phenomena at temperatures higher than T{sub C} are greatly influenced by nanodomains concentration and their shape. We show that about room temperature

Investigation of magnetocaloric effect in La{sub 0.45}Pr{sub 0.25}Ca{sub 0.3}MnO{sub 3} by magnetic, differential scanning calorimetry and thermal analysis

Energy Technology Data Exchange (ETDEWEB)

Aparnadevi, M; Barik, S K [Department of Physics, 2 Science Drive 3, National University of Singapore, Lower Kent Ridge Road, Singapore-117 452 (Singapore); Mahendiran, R [Department of Physics, 2 Science Drive 3, National University of Singapore, Lower Kent Ridge Road, Singapore-117 452 (Singapore)

2012-10-15

We investigated magnetocaloric effect in La{sub 0.45}Pr{sub 0.25}Ca{sub 0.3}MnO{sub 3} by direct methods (changes in temperature and latent heat) and indirect method (magnetization isotherms). This compound undergoes a first-order paramagnetic to ferromagnetic transition with T{sub C}=200 K upon cooling. The paramagnetic phase becomes unstable and it transforms into a ferromagnetic phase under the application of magnetic field, which results in a field-induced metamagnetic transition (FIMMT). The FIMMT is accompanied by release of latent heat and temperature of the sample as evidenced from differential scanning calorimetry and thermal analysis experiments. A large magnetic entropy change of {Delta}S{sub m}=-7.2 J kg{sup -1} K{sup -1} at T=212.5 K and refrigeration capacity of 228 J kg{sup -1} are found for a field change of {Delta}H=5 T. It is suggested that destruction of magnetic polarons and growth of ferromagnetic phase accompanied by a lattice volume change with increasing magnetic field is responsible for the large magnetocaloric effect in this compound. - Highlights: Black-Right-Pointing-Pointer We report magnetic entropy change measured by indirect and direct methods in La{sub 0.45}Pr{sub 0.25}Ca{sub 0.3}MnO{sub 3.} Black-Right-Pointing-Pointer Anomalous field-induced induced metamagnetic transition is found in the paramagnetic state. Black-Right-Pointing-Pointer A large reversible magnetic entropy change ({Delta}S{sub m}=7.2 J kg{sup -1} K{sup -1} for {Delta}H=5 T). Black-Right-Pointing-Pointer A large refrigeration capacity (RC=228 J kg{sup -1}). Black-Right-Pointing-Pointer Collapse of magnetic polarons is suggested as possible origin of the large MCE.

Structural, optical and spectroscopical investigations into rare-earths perowskites RGaO{sub 3} (R=La, Pr, Nd) and NdBa-2Cu{sub 3}O{sub 7-{delta}}; Strukturelle, optische und spektroskopische Untersuchungen von Seltenen-Erd-Perowskiten RGaO{sub 3} (R=La, Pr, Nd) und NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Marti, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1995-07-01

In this work I was engaged in rare-earth perovskites. Primarily I investigated the structure of the rare-earth gallates RGaO{sub 3} (R=La, Pr, Nd) as a function of the temperature by means of neutron diffraction and x-ray diffraction. As the high-T{sub c} superconductors these compounds belong to the family of the perovskites, they are ferroelastic and centro-symmetric. Because of the lanthanide-contraction all lattice constants and distortion parameters change systematically. The rare-earth-gallates RGaO{sub 3} (R=La, Pr, Nd) are promising substrates for epitaxy of high-T{sub c} superconductors like RBa{sub 2}Cu{sub 3}OO{sub 7-{delta}} because of their structure parameters and expansion coefficients. I succeeded in producing plane-parallel single-domain crystals by means of uniaxial stress. The first order phase transition was observable only in LaGaO{sub 3}. A structurally phase transition from orthorhombic to rhombohedral symmetry (high-temperature phase) occurs at 423 K. The hysteresis of the phase transition temperature of about 1.5 K was measured with single-domain crystals by means of neutron diffraction and polarized light microscopy. In NdGaO{sub 3} we determined the long-range, three-dimensional, antiferromagnetic ordering of the Nd{sup 3+}-ions below the ordering temperature at T{sub N}=0.97 K by means of magnetic neutron diffraction. The spin configuration could be described by a (--c{sub z})-mode. Measurements of the magnetic susceptibility confirm the easy direction of magnetization to be the c-axis. Below 300mK an additional nuclear spin polarization due to the hyperfine-interaction appears parallel to the electronic spins, which amounts to 70% at 10mK. Further I investigated the optical properties of the rare-earth gallates. The birefringence of plane-parallel, polished single-domain crystals with thickness up to 300 {mu}m was measured by means of orthoscopy and conoscopy. (author) figs., tabs., refs.

Improved ferroelectric and photoluminescence properties in Pr3+ substituted Na0.5Bi0.5TiO3 synthesized using hydrothermal route

Science.gov (United States)

Goutham, Cilaveni; Kandula, Kumara Raja; Raavi, Sai Santhosh Kumar; Asthana, Saket

2018-04-01

Nanocrystalline Pr3+ substituted NBT was synthesized using hydrothermal technique. Pr3+ modifies the ferroelectric NBT optically active and enhances the electrical properties with small structural changes. Aiming to the development of the bottom up optoelectronic devices this optimized nanoscale Na0.5Bi0.5-xPrxTiO3(x = 0.005) compound is synthesized hydrothermally. X-ray diffraction pattern shows that the system is stabilized in the Rhombohedral (space groupR3c) phase indicating the local strain inhomogeneity. PE loop shows that there is a decrement in the Ec value compared with compounds synthesized using conventional methods. The strong red emission assigned to prominent transition of the Pr3+ ions at 610nm was observed along with weak blue-green emission, indicating the potential use of the system. Energy transfer from host system to Pr3+ ions is responsible for red emission while blue green emission is due to quenching of 3P0 induced by intervalence charge transfer state.

Luminescent and scintillation properties of the Pr"3"+ doped single crystalline films of Lu_3Al_5_−_xGa_xO_1_2 garnet

International Nuclear Information System (INIS)

Gorbenko, V.; Zorenko, Yu; Zorenko, T.; Voznyak, T.; Paprocki, K.; Fabisiak, K.; Fedorov, A.; Bilski, P.; Twardak, A.; Zhusupkalieva, G.

2016-01-01

The Pr"3"+ d–f luminescence was investigated in the single crystalline films (SCF) of Lu_3Al_5_−_xGa_xO_1_2:Pr garnet solid solution at x = 1–3, grown by the liquid phase epitaxy (LPE) method from the melt-solution based on the PbO–B_2O_3 flux. The shape of CL spectra and decay kinetics of Pr"3"+ ions in Lu_3Al_5_−_xGa_xO_1_2 SCFs strongly depend on the total gallium concentration x and distribution of Ga"3"+ ions between the tetrahedral and octahedral position of the garnet host. The best scintillation properties of Lu_3Al_5_−_xGa_xO_1_2:Pr SCF are achieved at the nominal Ga content in melt-solution in the x = 2–2.5 range. - Highlights: • Single crystalline films of Lu_3Al_5_−_x Ga_xO_1_2:Pr garnet at x = 1–3 were grown by the LPE method. • Pr"3"+ emission spectra, light yield and decay time of films show strong dependence on Ga content. • The maximal light yield of Lu_3Al_5_−_x Ga_xO_1_2:Pr film is observed at Ga content x = 2.0–2.5.

Benchmark test of JENDL-3T and -3T/Rev.1

International Nuclear Information System (INIS)

Takano, Hideki; Kaneko, Kunio.

1989-10-01

The fast reactor 70-group constant set JFS-3-J3T has been generated by using the JENDL-3T nuclear data. One-dimensional 21-benchmark cores and the ZPPR-9 core were analysed with the JFS-3-J3T set. The results obtained are summarized as follows: (1) The values of keff are underestimated by 0.6% for Pu-fueled cores and overestimated by 2% for U-fueled cores. (2) The central reaction rate ratio 239 σ f φ/ 235 σ f φ is in a good agreement with the experimental value, though 238 σ c φ/ 239 σ f φ and 238 σ f φ/ 235 σ f φ are overestimated. (3) Doppler and Na-void reactivities are in a good agreement with the measured data. (4) The prediction accuracy of radial reaction rate distributions are improved in the comparison of the results obtained with the JENDL-2 data. Furthermore, the benchmark test of JENDL-3T/Rev. 1 which was revised from JENDL-3T for several important nuclides has been again performed. It was shown that JENDL-3T/Rev. 1 would predict nuclear characteristics more satisfactorily than JENDL-3T. (author)

Low-temperature magnetic ordering in the perovskites Pr1-xAxCoO3 (A=Ca, Sr)

International Nuclear Information System (INIS)

Deac, Iosif G.; Tetean, Romulus; Balasz, Istvan; Burzo, Emil

2010-01-01

The magnetic and electrical properties of polycrystalline Pr 1-x A x CoO 3 cobaltites with A=Ca, Sr and 0≤x≤0.5 were studied in the temperature range 4 K≤T≤1000 K and field up to 7 T. The X-ray analyses show the presence of only one phase having monoclinic or orthorhombic symmetry. The magnetic measurements indicate that the Ca-doped samples have at low temperatures, similar properties to the frustrated magnetic materials. PrCoO 3 is a paramagnetic insulator in the range from 4 to 1000 K. The Sr-doped cobaltites exhibit two phase transitions: a paramagnetic-ferromagnetic (or magnetic phase separated state) phase transition at about 240 K and a second one at about 100 K. The magnetic measurements suggest the presence of magnetic clusters and a change in the nature of magnetic coupling between Co ions at low temperatures. A semiconducting type behavior and high negative magnetoresistance was found for the Ca-doped samples, while the Sr-doped ones were metallic and with negligible magnetoresistance. The results are analyzed in the frame of a phase separation scenario in the presence of the spin-state transitions of Co ions.

Synthesis and luminescence characterization of Pr3+ doped Sr1.5Ca0.5SiO4 phosphor

Science.gov (United States)

Vidyadharan, Viji; Mani, Kamal P.; Sajna, M. S.; Joseph, Cyriac; Unnikrishnan, N. V.; Biju, P. R.

2014-12-01

Luminescence properties of Pr3+ activated Sr1.5Ca0.5SiO4 phosphors synthesized by solid state reaction method are reported in this work. Blue, orange red and red emissions were observed in the Pr3+ doped sample under 444 nm excitation and these emissions are assigned as 3P0 → 3H4, 3P0 → 3H6 and 3P0 → 3F4 transitions. The emission intensity shows a maximum corresponding to the 0.5 wt% Pr3+ ion. The decay analysis was done for 0.05 and 0.5 wt% Pr3+ doped samples for the transition 3P0 → 3H6. The life times of 0.05 and 0.5 wt% Pr3+ doped samples were calculated by fitting to exponential and non-exponential curve respectively, and are found to be 156 and 105 μs respectively. The non-exponential behaviour arises due to the statistical distribution of the distances between the ground state Pr3+ ions and excited state Pr3+ ions, which cause the inhomogeneous energy transfer rate. The XRD spectrum confirmed the triclinic phase of the prepared phosphors. The compositions of the samples were determined by the energy dispersive X-ray spectra. From the SEM images it is observed that the particles are agglomerated and are irregularly shaped. IR absorption bands were assigned to different vibrational modes. The well resolved peaks shown in the absorption spectra are identical to the excitation spectra of the phosphor samples. Pr3+ activated Sr1.5Ca0.5SiO4 phosphors can be efficiently excited with 444 nm irradiation and emit multicolour visible emissions. From the CIE diagram it can be seen that the prepared phosphor samples give yellowish-green emission.

75 FR 10026 - Proposed Collection; Comment Request for Forms W-2, W-2c, W-2AS, W-2GU, W-2VI, W-3, W-3c, W-3cPR...

Science.gov (United States)

2010-03-04

... W-2, W-2c, W-2AS, W-2GU, W-2VI, W-3, W-3c, W-3cPR, W-3PR, and W-3SS AGENCY: Internal Revenue Service....C. 3506(c)(2)(A)). Currently, the IRS is soliciting comments concerning Forms W-2, W-2c, W-2AS, W-2GU, W-2VI, W-3, W-3c, W- 3cPR, W-3PR, and W-3SS. DATES: Written comments should be received on or...

Energy transfer in Pr3+ and Mn2+ co-doped SrB6O10 and SrB4O7

International Nuclear Information System (INIS)

Chen Yonghu; Yan Wuzhao; Shi Chaoshu

2007-01-01

The luminescent properties of Pr 3+ and Mn 2+ -doped SrB 6 O 10 and SrB 4 O 7 powder samples were investigated from the point of view of energy transfer between Pr 3+ and Mn 2+ . The emission from the 1 S 0 level of Pr 3+ was found in the SrB 6 O 10 :Pr 3+ sample as well as in the SrB 4 O 7 :Pr 3+ sample, indicating the 1 S 0 level is below the lowest 4f5d energy level in these hosts. The spectral overlaps between the emission spectra of Pr 3+ -doped samples and the excitation spectra of Mn 2+ -doped sample were found in both kinds of strontium borates. These spectral overlaps are in favor of the energy transfer from Pr 3+ to Mn 2+ . However, in the emission spectra of the SrB 6 O 10 :Pr 3+ , Mn 2+ , no indication of energy transfer was observed, though the emission spectra of SrB 4 O 7 :Pr 3+ , Mn 2+ did show evidence of energy transfer from Pr 3+ to Mn 2+ . The possible reasons were discussed

Interaction of La3+, Ce3+, Pr3+ and Sm3+ with DL-aspartic acid in dimethyl sulphoxide

International Nuclear Information System (INIS)

Saxena, M.C.; Saxena, R.S.

1980-01-01

La(III), Ce(III), Pr(III) and Sm(III) form 1:1 and 1:2 complexes with DL-aspartic acid in 20% aq. dimethyl sulphoxide at μ = 0.1M (NaClO 4 ) as revealed by pH-metric and conductometric titrations. Stabilities of the complexes follow the order: La 3+ 3+ 3+ 3+ . The overall changes in ΔG, ΔH and ΔS for the metal-ligand interaction have also been reported at 30deg C. (auth.)

Magnetic relaxation behaviour in Pr_2NiSi_3

International Nuclear Information System (INIS)

Pakhira, Santanu; Mazumdar, Chandan; Ranganathan, R.

2016-01-01

Time dependent isothemal remanent magnetizatin (IRM) behaviour for polycrystalline compound Pr_2NiSi_3 have been studied below its characteristic temperature. The compound undergoes slow magnetic relaxation with time. Along with competing interaction, non-magnetic atom disorder plays an important role in formation of non-equilibrium glassy like ground state for this compound.

Comparative investigation on the spectroscopic properties of Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses

Science.gov (United States)

Zhang, Liaolin; Dong, Guoping; Peng, Mingying; Qiu, Jianrong

We report on the spectroscopic properties of Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses. The stimulated absorption and emission cross sections were estimated. Only one emission at 596 nm and 605 nm is observed in Pr3+-doped boro-phosphate and boro-germo-silicate glasses, respectively, while three emissions at 605 nm, 612 nm and 645 nm are observed in Pr3+-doped tellurite glass when excited at 467 nm. The fluorescence lifetime at 600 nm in Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses is 137 μs, 73 μs and 51 μs, respectively. The emissions from Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses show different decay behaviors and can be well explained by multiphonon relaxation theory.

Thermoelectric performance enhancement of SrTiO3 by Pr doping

KAUST Repository

Kahaly, M. Upadhyay; Schwingenschlö gl, Udo

2014-01-01

We investigate Pr doping at the Sr site as a possible route to enhance the thermoelectric behavior of SrTiO3-based materials, using first principles calculations in full-potential density functional theory. The effects of the Pr dopant on the local electronic structure and resulting transport properties are compared to common Nb doping. We demonstrate a substantial enhancement of the thermoelectric figure of merit and develop an explanation for the positive effects, which opens new ways for materials optimization by substitutional doping at the perovskite B site. © 2014 the Partner Organisations.

Energy transfer from Pr3+ to Gd3+ ions in BaB8O13 phosphor for phototherapy lamps

Science.gov (United States)

Tamboli, Sumedha; Nair, Govind B.; Dhoble, S. J.; Burghate, D. K.

2018-04-01

A series of BaB8O13 phosphors doped with different concentrations of Gd3+ ions and co-doped with Pr3+ ions were synthesized by solid state synthesis method. X-ray powder diffraction (XRD) analysis confirmed the formation of the compound in a crystalline and homogeneous form. Scanning Electron Microscopy (SEM) was performed to study the surface morphology of the compound and Fourier Transform Infrared (FT-IR) spectroscopy measurements determined the nature of bonding between elements of the compounds. The photoluminescence (PL) excitation spectra of BaB8O13:Gd3+ phosphor showed excitation peaks at 246 nm, 252 nm and 274 nm. The prominent emission peak was observed at 313 nm which is in narrow band ultraviolet B (NB-UVB) range. Energy transfer was achieved by co-doping Pr3+ ions with Gd3+ ions. PL decay time was also measured for BaB8O13: Gd3+, Pr3+ phosphor. Emission at 313 nm can be used for the treatment of skin diseases.

Significant enhancement in thermoelectric properties of polycrystalline Pr-doped SrTiO3−δ ceramics originating from nonuniform distribution of Pr dopants

KAUST Repository

Dehkordi, Arash Mehdizadeh

2014-05-12

Recently, we have reported a significant enhancement ( >70% at 500 °C) in the thermoelectric power factor (PF) of bulk polycrystalline Pr-doped SrTiO3 ceramics employing a novel synthesis strategy which led to the highest ever reported values of PF among doped polycrystalline SrTiO3. It was found that the formation of Pr-rich grain boundary regions gives rise to an enhancement in carrier mobility. In this Letter, we investigate the electronic and thermal transport in Sr1− x Pr x TiO3 ceramics in order to determine the optimum doping concentration and to evaluate the overall thermoelectric performance. Simultaneous enhancement in the thermoelectric power factor and reduction in thermal conductivity in these samples resulted in more than 30% improvement in the dimensionless thermoelectric figure of merit (ZT) for the whole temperature range over all previously reported maximum values. Maximum ZT value of 0.35 was obtained at 500 °C.

Significant enhancement in thermoelectric properties of polycrystalline Pr-doped SrTiO3−δ ceramics originating from nonuniform distribution of Pr dopants

KAUST Repository

Dehkordi, Arash Mehdizadeh; Bhattacharya, Sriparna; He, Jian; Alshareef, Husam N.; Tritt, Terry M.

2014-01-01

Recently, we have reported a significant enhancement ( >70% at 500 °C) in the thermoelectric power factor (PF) of bulk polycrystalline Pr-doped SrTiO3 ceramics employing a novel synthesis strategy which led to the highest ever reported values of PF among doped polycrystalline SrTiO3. It was found that the formation of Pr-rich grain boundary regions gives rise to an enhancement in carrier mobility. In this Letter, we investigate the electronic and thermal transport in Sr1− x Pr x TiO3 ceramics in order to determine the optimum doping concentration and to evaluate the overall thermoelectric performance. Simultaneous enhancement in the thermoelectric power factor and reduction in thermal conductivity in these samples resulted in more than 30% improvement in the dimensionless thermoelectric figure of merit (ZT) for the whole temperature range over all previously reported maximum values. Maximum ZT value of 0.35 was obtained at 500 °C.

AC Electroluminescent Processes in Pr3+-Activated (Ba0.4Ca0.6TiO3 Diphase Polycrystals

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Nan Gao

2017-05-01

Full Text Available We investigated the properties of alternating current (AC-driven electroluminescence from (Ba0.4Ca0.6TiO3:Pr3+ diphase polycrystal-based device. The results of crystal phases and micrographs, and the symmetrical dual emissions in one AC cycle, indicate the spontaneous formation of a dielectric/phosphor/dielectric sandwich microstructure in (Ba0.4Ca0.6TiO3:Pr3+. The electroluminescent device emits a red light of 617 nm, which is attributed to the 1D2-3H4 transition of Pr3+ in the phosphor phase. At a fixed AC frequency, the intensity of electroluminescence exhibits a steep enhancement when applying an increased driving electric field that is beyond a threshold. In a fixed driving electric field, the intensity of electroluminescence shows a rapid rise at low frequencies, but reaches saturation at high frequencies. Based on a double-injection model, we discussed systematically the electroluminescent processes in a whole cycle of AC electric field, which matched well with the experimental data. Our investigation is expected to expand our understanding of such a diphase electroluminescent device, thereby promoting their applications in lighting and displays.

Texturation à froid sous contraintes triaxiales de phase à haute T_c de Bi(Pb)SrCaCuO préréagie

Science.gov (United States)

Langlois, P.; Massat, H.; Suryanarayanan, R.

1994-11-01

The alignment of grains in isostatically precompacted samples of prereacted Bi{1,8}Pb{0,4}Sr{2,0}Ca{2,2}Cu{3,0}O{10,3 + x} powder has been achieved by compressive plastic deformation under isostatic pressure at room temperature. Isostatic pressures were in the range 0.1 to 1 GPa and deformation rates were led up to 57 %. Prior to sintering, X-ray diffraction measurements corroborate an expected high- T_c phase purity of nearly 85 % and indicate that the as-deformed samples have been textured with the (c-axes parallel to the pressing direction whilst a.c. susceptibility measurements ascertain a high transition temperature around 107 K. Intergranular connection does not occur until sintering at 850 ^{circ}C for 80 h and measurements indicate then that the texture has been retained. Superconducting properties themselves show sensitivity to texture through anisotropy-related distinctive irreversibility lines. L'alignement de grains de poudre Bi{1,8}Pb{0,4}Sr{2,0}Ca{2,2}Cu{3,0}O{10,3 + x} préréagie a été réalisé par déformation plastique à température ambiante d'échantillons précompactés isostatiquement et comprimés sous pression isostatique, la gamme des pressions isostatiques allant de 0,1 à 1 GPa et les taux de déformation atteignant 57 %. Les mesures de diffraction de rayons X corroborent la pureté de phase à haute T_c proche de 85 % attendue et indiquent que les échantillons ainsi déformés ont été texturés avec les plans ab perpendiculaires à la direction de compression. Les mesures de susceptibilité alternative avèrent une température élevée de transition à environ 107 K mais la connexion intergranulaire n'est assurée qu'après un frittage à 850 ^{circ}C pendant 80 h dont on vérifie qu'il conserve la texture. Enfin, la sensibilité des propriétés supraconductrices à la texturation est évaluée par le biais de lignes d'irréversibilité distinctes en fonction de l'anisotropie.

Indication for a chiral phase in the molecular magnetic chain Gd(hfac){sub 3}NiTiPr by specific heat and {mu}{sup +}SR measurements

Energy Technology Data Exchange (ETDEWEB)

Lascialfari, A.; Ullu, R.; Affronte, M.; Cinti, F.; Caneschi, A.; Gatteschi, D.; Rovai, D.; Pini, M.G. E-mail: mgpini@ifac.cnr.it; Rettori, A

2004-05-01

Specific heat and muon spin relaxation ({mu}{sup +}SR) measurements performed in the molecular magnetic chain Gd(hfac){sub 3}NiTiPr provide indication for the onset, at T{sub 0}=2.08 K, of a phase with chiral order in the absence of long-range helical order. Specific heat data (probing the chirality-chirality correlation function) show a peak at T{sub 0} that disappears upon application of a 5 T magnetic field, while {mu}{sup +}SR data (probing the spin-spin correlation function) do not present any anomaly at T{sub 0} nor oscillations in the asymmetry curve below T{sub 0}.

Major enhancement of the thermoelectric performance in Pr/Nb-doped SrTiO3 under strain

KAUST Repository

Amin, B.

2013-07-16

The electronic structure and thermoelectric properties of strained (biaxially and uniaxially) Sr0.95Pr0.05TiO3 and SrTi0.95Nb0.05O3 are investigated in the temperature range from 300 K to 1200 K. Substitutions of Pr at the Sr site and Nb at the Ti site generate n-type doping and thus improve the thermoelectric performance as compared to pristine SrTiO3. Further enhancement is achieved by the application of strain, for example, of the Seebeck coefficient by 21% for Sr0.95Pr0.05TiO3 and 10% for SrTi0.95Nb0.05O3 at room temperature in the case of 5% biaxial strain. At 1200 K, we predict figures of merit of 0.58 and 0.55 for 2.5% biaxially strained Sr0.95Pr0.05TiO3 and SrTi0.95Nb0.05O3 , respectively, which are the highest values reported for rare earth doped SrTiO3.

The influence of substituting Si for Co on the magnetic properties of PrCo5

International Nuclear Information System (INIS)

Coroian, N.; Klosek, V.; Isnard, O.

2007-01-01

The crystal structure and magnetic properties of the PrCo 4.5 Si 0.5 compound have been investigated. PrCo 4.5 Si 0.5 is found to be ferromagnetic in the whole ordered region with a CaCu 5 crystal structure type. The Si for Co substitution induces an important reduction of the Curie temperature (T C ), T C that reaches 645(2)K. At 4K, the saturation magnetization is 8.0μ B /f.u. Powder neutron diffraction data show that the Co atoms from non-equivalent atomic sites (2c, 3g) are exhibiting a similar magnetic behavior. The magnitude of the atomic magnetic moments diminishes with increasing temperature. At low temperatures, the magnetic moments are tilted away from the c-axis. As the temperature increases the magnetic moments become parallel to it. This spin reorientation is observed between 50 and 90K in PrCo 4.5 Si 0.5 . At 300K the atomic magnetic moments are μ Co 2c =1.19(3)μ B , μ Co 3g =0.98(3)μ B , μ Pr =0.59(8)μ B being aligned along the c-axis. The Si atoms are localized exclusively at the 3g site, thus favoring an enhancement of the uniaxial anisotropy

Práticas de biossegurança no ensino técnico de enfermagem

Directory of Open Access Journals (Sweden)

Gerusa Ribeiro

Full Text Available Resumo A biossegurança é um componente central a ser considerado para que os profissionais executem suas atividades minimizando danos à sua saúde e à de usuários dos serviços de saúde. As instituições educacionais e os(as enfermeiros(as docentes têm papel fundamental nesse processo. Com o objetivo de compreender a prática da biossegurança realizada por enfermeiros(as docentes durante a supervisão de estágio de alunos de cursos técnicos de enfermagem, realizou-se uma pesquisa exploratória descritiva, de abordagem qualitativa. Os dados foram coletados no ano de 2012, com 11 enfermeiros(as docentes de duas instituições da rede federal de educação profissional, científica e tecnológica na região Sul do Brasil. Utilizou-se triangulação metodológica com dados coletados por meio de estudo documental, entrevista semiestruturada e observação, orientados pela análise temática de conteúdo de Bardin. Os resultados mostraram que as ações dos docentes em relação à biossegurança são influenciadas pela disponibilidade e acesso aos materiais e equipamentos, pela quantidade e qualidade dos equipamentos de proteção individual, pela infraestrutura das instituições assistenciais e laboratórios de ensino e pelo conhecimento do tema. Concluiu-se que as ações protetoras na prática docente são influenciadas pelo conhecimento, pelas condições de trabalho e pelas escolhas dos sujeitos.

Development and characterization of radioimmunoassay methods for the measurement of iodothyronines (T4, T3 and rT3)

International Nuclear Information System (INIS)

Russo, E.M.K.; Vieira, J.G.H.; Barros Maciel, R.M. de; Fonseca, R.M.G.

1982-01-01

The experience acquired in the development of radioimmunoassay for T 4 , T 3 and rT 3 in unextrated serum is described. Antisera were produced in rabbits using iodothyronines conjugated to bovine serum albumin: the antisera selected provided the development of sensitive and specific radioassay methods. Stable high activity T 3 , T 4 and rT 3 tracers were prepared by iodination of 3,5 T 2 , T 3 and 3,3' T 2 by the chloramine-T method, and purified by column chromatography on Sephadex G25. Binding of those iodothyronines to endogenous serum proteins was blocked by including 8-aniline-1-naphtalene sulphonic acid (ANSA) in the T 4 and T 3 assays and thymerosal in the rT 3 assay. Normal values were defined in 46 healthy euthyroid adults of both sexes: T 4 = 7,1 +- 1,3μg/dl; T 3 = 139 +- 35ng/dl and rT 3 = 18,0 +- 7,9ng/dl. (Author) [pt

μ+ relaxation correlated with susceptibility in the van-Vleck paramagnet PrIn3

International Nuclear Information System (INIS)

Grayevsky, A.; Amato, A.; Pinkpank, M.; Schenck, A.

1997-01-01

A previously unobserved increase of the magnetic susceptibility in PrIn 3 at low temperatures is reported. The increase is shown to correlate nicely with a large increase in the transverse μSR depolarization rate. Evidence supports the conclusion that both phenomena are related to some degree of atomic disorder in the structure, and an associated strong Pr CEF level changes. (orig.)

What is new in Office 2007 - (IT3T/2007/2)

CERN Multimedia

CERN. Geneva

2007-01-01

IT3T/2007/2 - Quoi de neuf avec Office 2007 Nous allons présenter le nouveau type de site web disponible au CERN: "Collaboration Workspaces". Avec des fonctionnalités comme les forums de discussion, les pages wiki, la création rapide de formulaires web et les "document libraries", nous montrerons comment les Collaboration Workspaces permettent de publier, partager et récupérer l'information de manière plus simple et plus rapide, et permettent de collaborer de manière efficace sur les documents. IT3T/2007/2 - What is new in Office 2007 The presentation will introduce the new features of Microsoft Office 2007 including the new Microsoft Office Fluent user interface and explain how to use the Ribbon, Contextual Tabs, Galleries, and Live Preview. No special previous knowledge is required, at the same time a basic knowledge of Office 2003 applications (Word/Excel/PowerPoint) may be a convenient starting point.

Critical current density in (YBa2Cu3O7-δ)1-x-(PrBa2Cu3O7-δ)x melt-textured composites

Science.gov (United States)

Opata, Yuri Aparecido; Monteiro, João Frederico Haas Leandro; Jurelo, Alcione Roberto; Siqueira, Ezequiel Costa

2018-06-01

Melt textured (YBa2Cu3O7-δ)1-x-(PrBa2Cu3O7-δ)x composites (x = 0.00 and x = 0.05) were grown using the top seeding method. The effect of the PrBa2Cu3O7-δ phase on the growth process and the modification of the microstructure as well as on the physical properties was analyzed. X-ray analyses indicated that both pure and Pr-doped samples present an orthorhombic superconducting phase. From resistivity measurements for YBa2Cu3O7-δ and (YBa2Cu3O7-δ)0.95-(PrBa2Cu3O7-δ)0.05 samples, the Tcab did not change and was around 90.5 K. However, from magnetic measurements, the superconductivity was observed in critical temperatures TC = 92.9 K and 92.4 K for YBa2Cu3O7-δ and (YBa2Cu3O7-δ)0.95-(PrBa2Cu3O7-δ)0.05 samples, respectively. The YBa2Cu3O7-δ sample showed higher critical current densities than those shown by the (YBa2Cu3O7-δ)0.95-(PrBa2Cu3O7-δ)0.05 sample, with values of JC = 5.85 × 105 A/cm2 and 4.72 × 105 A/cm2, respectively. This paper also discusses the importance of Pr substitution on nano- and micro-meter scales to enhance JC(H).

Synthesis and characterization of physical properties of Gd{sub 2}O{sub 2}S:Pr{sup 3+} semi-nanoflower phosphor

Energy Technology Data Exchange (ETDEWEB)

Bagheri, A.; Rezaee Ebrahim Saraee, Kh.; Shakur, H.R. [University of Isfahan, Department of Nuclear Engineering, Faculty of Advance Sciences and Technologies, Isfahan (Iran, Islamic Republic of); Zamani Zeinali, H. [Nuclear Science and Technology Research Institute, Agriculture, Medical and Industrial Research School, Karaj (Iran, Islamic Republic of)

2016-05-15

Pure gadolinium oxysulfide phosphor (Gd{sub 2}O{sub 2}S) and trivalent praseodymium-doped gadolinium oxysulfide phosphor (Gd{sub 2}O{sub 2}S:Pr{sup 3+}) scintillators with semi-nanoflower crystalline structures were successfully synthesized through a precipitation method and subsequent calcination treatment as a converter for X-ray imaging detectors. The characterization such as the crystal structures and nanostructure of Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator measured by XRD and FeE-SEM experiment. The optical properties of Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator were studied. Luminescence spectra of Gd{sub 2}O{sub 2}S:Pr{sup 3+} under 320 nm UV excitation show a green emission at near 511 nm corresponding to the {sup 3}P{sub 0}-{sup 3}H{sub 4} of Pr ions. After scintillation properties of synthesized Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator investigated, Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillating film fabricated on a glass substrate by a sedimentation method. X-ray imaging of the fabricated scintillators confirmed that the Gd{sub 2}O{sub 2}S:Pr{sup 3+} scintillator could be used for radiography applications in which good spatial resolution is needed. (orig.)

Characterizations of Pr-doped Yb3Al5O12 single crystals for scintillator applications

Science.gov (United States)

Yoshida, Yasuki; Shinozaki, Kenji; Igashira, Takuya; Kawano, Naoki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

2018-04-01

Yb3Al5O12 (YbAG) single crystals doped with different concentrations of Pr were synthesized by the Floating Zone (FZ) method. Then, we evaluated their basic optical and scintillation properties. All the samples showed photoluminescence (PL) with two emission bands appeared approximately 300-500 nm and 550-600 nm due to the charge transfer luminescence of Yb3+ and intrinsic luminescence of the garnet structure, respectively. A PL decay profile of each sample was approximated by a sum of two exponential decay functions, and the obtained decay times were 1 ns and 3-4 ns. In the scintillation spectra, we observed emission peaks in the ranges from 300 to 400 nm and from 450 to 550 nm for all the samples. The origins of these emissions were attributed to charge transfer luminescence of Yb3+ and intrinsic luminescence of the garnet structure, respectively. The scintillation decay times became longer with increasing the Pr concentrations. Among the present samples, the 0.1% Pr-doped sample showed the lowest scintillation afterglow level. In addition, pulse height spectrum of 5.5 MeV α-rays was demonstrated using the Pr-doped YbAG, and we confirmed that all the samples showed a full energy deposited peak. Above all, the 0.1% Pr-doped sample showed the highest light yield with a value of 14 ph/MeV under α-rays excitation.

Synthesis and characterization of highly efficient and stable Pr6O11/Ag3PO4/Pt ternary hybrid structure

International Nuclear Information System (INIS)

Deng, Jiatao; Liu, Lin; Niu, Tongjun; Sun, Xiaosong

2017-01-01

Highlights: • Visible-light-driven Pr 6 O 11 /Ag 3 PO 4 /Pt photocatalysts were prepared. • Pr 6 O 11 /Ag 3 PO 4 /Pt showed highly efficient and stable photocatalystic activity. • The photocatalytic mechanism of Pr 6 O 11 /Ag 3 PO 4 /Pt composite was given. - Abstract: Ag 3 PO 4 is an excellent photocatalyst with high efficiency and quantum yield, but suffers from the fast recombination of photogenerated electron-hole pairs and photo-corrosion. Hereby, the highly efficient and stable visible-light-driven Pr 6 O 11 /Ag 3 PO 4 /Pt photocatalyst were prepared via a three-step wet chemical approach. The as-prepared Pr 6 O 11 /Ag 3 PO 4 /Pt composite was characterized by X-ray diffraction, US-vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra and transient photocurrent as well. Comparing with single Pr 6 O 11 or Ag 3 PO 4 , the prepared Pr 6 O 11 /Ag 3 PO 4 /Pt composite exhibited much higher photocatalytic activity and stability for the degradation of Rhodamine B under visible light irradiation (>420 nm). The enhanced photocatalytic performance of Pr 6 O 11 /Ag 3 PO 4 /Pt composite has been attributed to the efficient separation of photo-generated electron-hole pairs through a scheme system composed of Pr 6 O 11, Ag 3 PO 4 and Pt.

Electronic changes induced by μ+ in PrIn3: Muon-spin-rotation observation and crystalline-electric-field model calculation

International Nuclear Information System (INIS)

Tashma, T.; Amato, A.; Grayevsky, A.; Gygax, F.N.; Pinkpank, M.; Schenck, A.; Kaplan, N.

1997-01-01

Muon spin rotation in a single crystal of PrIn 3 reveals a significant influence of the implanted μ + on the local susceptibility χ 1 of the neighboring Pr +3 ions below ∼60K. It is found that χ 1 differs from χ bulk both in magnitude and in symmetry. All of the changes are accounted for by a model calculation based on crystalline-electric-field theory. The extent of the μ + -induced magnetic changes in the present system of PrIn 3 is rather modest compared to previously reported induced changes in PrNi 5 . However, the model-derived electronic-structure changes around the μ + in PrIn 3 appear remarkably similar to those in PrNi 5 , as is to be expected if the driving perturbation in both systems is primarily Coulombic in nature. copyright 1997 The American Physical Society

The PR in PN for Education Associations. PR Bookshelf, No. 3.

Science.gov (United States)

National Education Association, Washington, DC.

This booklet presents suggestions and guidelines for the effective use of public relations (PR) techniques during professional negotiations (PN) among teachers, administrators, and boards of education. Introductory sections present the National Education Association (NEA) position regarding professional negotiation and grievance procedures and…

Upconversion excitations in Pr3+-doped BaY2F8 crystal

Science.gov (United States)

Piramidowicz, R.; Mahiou, R.; Boutinaud, P.; Malinowski, M.

2011-09-01

We report the orange-to-blue and infrared-(IR)-to-blue wavelengths upconversion luminescence in Pr3+:BaY2F8 crystals. Mechanism of the orange light upconversion into blue 3P0 state emission was confirmed to be energy transfer between two Pr3+ ions in the 1D2 state. IR-to-blue upconversion has only been observed under two different color IR pumping. The first resonant step was the 3H4→1G4 ground state absorption transition, and the second resonant transition was the excited state absorption from the 1G4 to 1I6 and 3PJ levels. A comparison of the efficiency of the IR-to-blue upconversion in several praseodymium activated host is presented and discussed. A model of the IR pumped upconversion praseodymium blue laser is presented and the population inversion conditions are calculated.

Low-temperature magnetic ordering in the perovskites Pr 1-xA xCoO 3 (A=Ca, Sr)

Science.gov (United States)

Deac, Iosif G.; Tetean, Romulus; Balasz, Istvan; Burzo, Emil

2010-05-01

The magnetic and electrical properties of polycrystalline Pr 1-xA xCoO 3 cobaltites with A=Ca, Sr and 0≤ x≤0.5 were studied in the temperature range 4 K≤ T≤1000 K and field up to 7 T. The X-ray analyses show the presence of only one phase having monoclinic or orthorhombic symmetry. The magnetic measurements indicate that the Ca-doped samples have at low temperatures, similar properties to the frustrated magnetic materials. PrCoO 3 is a paramagnetic insulator in the range from 4 to 1000 K. The Sr-doped cobaltites exhibit two phase transitions: a paramagnetic-ferromagnetic (or magnetic phase separated state) phase transition at about 240 K and a second one at about 100 K. The magnetic measurements suggest the presence of magnetic clusters and a change in the nature of magnetic coupling between Co ions at low temperatures. A semiconducting type behavior and high negative magnetoresistance was found for the Ca-doped samples, while the Sr-doped ones were metallic and with negligible magnetoresistance. The results are analyzed in the frame of a phase separation scenario in the presence of the spin-state transitions of Co ions.

Leaf-specific pathogenesis-related 10 homolog, PgPR-10.3, shows in silico binding affinity with several biologically important molecules

Directory of Open Access Journals (Sweden)

Jin Haeng Han

2015-10-01

Conclusion: Although ginseng PR-10.3 gene is expressed in all organs of 3-wk-old plantlets, its expression is restricted to leaves in mature 2-yr-old ginseng plants. The putative binding property of PgPR-10.3 with Re is intriguing. Further verification of binding affinity with other biologically important molecules in the large hydrophobic cavity of PgPR-10.3 may provide an insight into the biological features of PR-10 proteins.

Comparison of post-contrast 3D-T1-MPRAGE, 3D-T1-SPACE and 3D-T2-FLAIR MR images in evaluation of meningeal abnormalities at 3-T MRI.

Science.gov (United States)

Jeevanandham, Balaji; Kalyanpur, Tejas; Gupta, Prashant; Cherian, Mathew

2017-06-01

This study was to assess the usefulness of newer three-dimensional (3D)-T 1 sampling perfection with application optimized contrast using different flip-angle evolutions (SPACE) and 3D-T 2 fluid-attenuated inversion recovery (FLAIR) sequences in evaluation of meningeal abnormalities. 78 patients who presented with high suspicion of meningeal abnormalities were evaluated using post-contrast 3D-T 2 -FLAIR, 3D-T 1 magnetization-prepared rapid gradient-echo (MPRAGE) and 3D-T 1 -SPACE sequences. The images were evaluated independently by two radiologists for cortical gyral, sulcal space, basal cisterns and dural enhancement. The diagnoses were confirmed by further investigations including histopathology. Post-contrast 3D-T 1 -SPACE and 3D-T 2 -FLAIR images yielded significantly more information than MPRAGE images (p evaluation of meningeal abnormalities and when used in combination have the maximum sensitivity for leptomeningeal abnormalities. The negative-predictive value is nearly 100%, where no leptomeningeal abnormality was detected on these sequences. Advances in knowledge: Post-contrast 3D-T 1 -SPACE and 3D-T 2 -FLAIR images are more useful than 3D-T 1 -MPRAGE images in evaluation of meningeal abnormalities.

TPA: Freie Hand für freien Handel? : US-Präsident Bushs Auseinandersetzung mit dem Kongress um seine handelspolitische Autorität

OpenAIRE

Braml, Josef; Schmucker, Claudia

2007-01-01

"Am 1. Juli 2007 endet die Vereinbarung, wonach der Kongress die vom amerikanischen Präsidenten vorgelegten internationalen Handelsabkommen nur noch als ganzes, das heißt ohne Änderungsanträge annehmen oder ablehnen kann. Damit wird auch die Verhandlungsmacht des Präsidenten auf internationaler Ebene (u.a. im Rahmen der Doha-Runde in der Welthandelsorganisation, WTO) berührt, nämlich Vereinbarungen ohne Wenn und Aber politisch durchsetzen zu können. Wie gut stehen Bushs Chancen, parteiü...

Effect of electromagnetic and phonon pulses on a photon echo in LaF3: Pr3+

International Nuclear Information System (INIS)

Shegeda, A.M.; Khabibullin, B.M.; Lisin, V.N.

1995-01-01

The effect of electromagnetic-field pulses of the nanosecond duration on the inverted two-pulse, three-pulse, and long-lived three-pulse photon echoes in LaF 3 :Pr 3+ is studied. The eletromagnetic pulses were produced by a current pulse flowing through a thin metal film evaporated on the sample surface parallel to the C 3- axis. A strong decrease in echo signals is observed, even if the eletromagnetic pulses were switched on prior to laser pulses. The experimental results can be qualitatively interpreted under the assumption that during the flowing of current through the metal film, the generation of transverse acoustic and electromagnetic fields occurs that induces the pseudo-Stark splitting of energy levels of Pr 3+ ions and, as a consequence, the decrease in echo signals, if the current was switched on prior to or, correspondingly, at the instant of the action of the laser pulses. 12 refs., 5 figs

Luminescent characteristics of UV excited Sr{sub 0.5}Ca{sub 0.5}TiO{sub 3}: Pr{sup 3+} reddish-orange phosphor

Energy Technology Data Exchange (ETDEWEB)

Vidyadharan, Viji; Mohan P, Remya; Joseph, Cyriac; Unnikrishnan, N.V.; Biju, P.R., E-mail: prb.mgu@gmail.com

2016-02-15

Pr{sup 3+} doped Sr{sub 0.5}Ca{sub 0.5}TiO{sub 3} phosphors were synthesised by solid state reaction process. The structure, surface morphology and photoluminescence of the prepared phosphors were analysed using XRD, SEM and photoluminescence spectroscopy respectively. The XRD pattern confirmed orthorhombic perovskite structure of the Sr{sub 0.5}Ca{sub 0.5}TiO{sub 3}: x Pr{sup 3+} phosphor. Agglomeration of particles with irregular shapes is observed from the SEM images. The emission spectra of Sr{sub 0.5}Ca{sub 0.5}TiO{sub 3}: x Pr{sup 3+} phosphor shows the samples can be effectively excited with UV light at 336 nm and exhibit a strong reddish-orange emission at 611 nm. Concentration dependence of emission intensity shows concentration quenching effect on increasing Pr{sup 3+} concentration after x = 0.1 because of dipole–dipole interaction. Using Blasse's formula, critical distance for energy transfer was calculated. The CIE co-ordinates, CCT, colour purity and luminescence decay of the prepared phosphors were also calculated. These results offer the prepared phosphor as a suitable candidate for various photonic applications. - Highlights: • Sr{sub 0.5}Ca{sub 0.5}TiO{sub 3}: x Pr{sup 3+} perovskite structured phosphors were synthesized. • Under UV excitation, the PL spectra show strong reddish-orange emission. • The emission from {sup 3}P{sub J} levels of Pr{sup 3+} were absent due to the presence of IVCT band. • Concentration quenching due to dipole–dipole interaction was observed. • For x = 0.1, sample shows a maximum emission intensity with 91.7% colour purity.

Thermally stimulated luminescence and persistent luminescence of β-irradiated YAG:Pr"3"+ nanophosphors produced by combustion synthesis

International Nuclear Information System (INIS)

Santacruz-Gomez, K.; Meléndrez, R.; Gil-Tolano, M.I.; Jimenez, J.A.; Makale, M.T.; Barboza-Flores, M.; Castaneda, B.; Soto-Puebla, D.; Pedroza-Montero, M.; McKittrick, J.; Hirata, G.A.

2016-01-01

In this work, the thermally stimulated luminescence (TSL) and persistent luminescence (PLUM) properties of praseodymium doped yttrium aluminum garnet (YAG:Pr"3"+) exposed to β-irradiation are reported. X-ray diffraction (XRD) confirms a single phase of YAG obtained by the combustion method. Transmission electron microscopy (TEM) shows that powder particles appear to be irregular crystals with an average size of 67 nm. TSL glow-curve deconvolution of YAG:Pr"3"+ after β-irradiation consist in six peaks centered at 394, 450, 467, 543, 637 and 705 K. The TSL fading and PLUM signals were found to be associated with at least with two different kinds of traps, corresponding to the peaks located at 394, 450 and 467 K. YAG:Pr"3"+ nanophosphors analyzed in this work showed interesting features about the dosimetric sensitivity as well as the reproducibility for both TSL/PLUM techniques, with good linearity dose response. These results indicate that nanocrystalline YAG:Pr3"+ is a good candidate for dosimetric applications in the range of 80 mGy-20 Gy. - Highlights: • β-irradiated YAG:Pr"3"+ TSL consist in 394, 450, 467, 543, 637 and 705 K peaks. • YAG:Pr"3"+ is a good candidate for dosimetry in the range of 80 mGy-20 Gy. • PLUM can be potentially used for in vivo, in situ and quasi in real time dosimetry.

Low-temperature resistivity anomaly in underdoped Pr0.8Sr0.2MnO3 manganite nanoparticles

International Nuclear Information System (INIS)

Das, Proloy T.; Giri, S.K.; Panda, J.; Taraphder, A.; Nath, T.K.; Nigam, A.K.

2013-01-01

High resolution electrical resistivity measurements were carried out of under-doped Pr 0.8 Sr 0.2 MnO 3 manganite nanoparticles with grain size modulation down to 40 nm in magnetic fields H, from 0 to 9 T in the low temperature regime down to a temperature of 4.2 K. In the temperature range below 80 K, a distinct resistivity minima is observed for all the samples with different particle sizes for all H. While trying to fit low temperature resistivity data with different models for the observed resistivity minima with negative temperature coefficient of resistance (TCR) for all H, it appears that all the data for different particle sizes, can be best described by electron-electron (e-e) interaction effect in comparison with other models, e.g., Kondo model, coulomb blockades etc. The low temperature data for all H have been fitted with an expression containing three terms, namely, residual resistivity, inelastic scattering, e-e interaction and Kondo effects. We conclude that the e-e interaction is the dominant transport mechanism at low temperatures for the observed negative TCR in this strongly disordered nanometric Pr 0.8 Sr 0.2 MnO 3 phase separated manganite system. (author)

PrP Conformational Transitions Alter Species Preference of a PrP-specific antibody

NARCIS (Netherlands)

Zou, W.Q.; Langeveld, J.P.M.; Xiao, X.; Chen, S.; McGeer, P.L.; Yuan, J.; Payne, M.C.; Kang, H.E.; McGeehan, J.M.; Sy, M.S.; Greenspan, N.S.; Kaplan, D.; Wang, G.X.; Parchi, P.; Hoover, E.A.; Kneale, G.; Telling, G.; Surewicz, W.; Kong, Q.; Guo, J.

2010-01-01

The epitope of the 3F4 antibody most commonly used in human prion disease diagnosis is believed to consist of residues Met-Lys-His-Met (MKHM) corresponding to human PrP-(109–112). This assumption is based mainly on the observation that 3F4 reacts with human and hamster PrP but not with PrP from

Die prädikatsergänzung (das prädikatsattribut in der Slovenischen Syntax

Directory of Open Access Journals (Sweden)

Breda Pogorelec

1972-12-01

Full Text Available In der vorliegenden Abhandlung wird die erwähnte Problematik in der slovenischen grammatischen -Überlieferung behandelt und mit interessanten Ergebnissen vor allem der tschechischen Sprachtheorie ergänzt, es wird der Terminus Prädikatsergänzung gegenüber dem Terminus Prädikatsattribut begründet; auf dieser Grundlage werden auch die bisher behandelten Arten von Prädikatsergänzungen mit neuen ergänzt. Dabei findet wenn nur möglich das einfache Transformationsverfahren Verwendung, das die Veranschaulichung der stufenweisen Determinierung durch das Prädikatsattribut ermöglicht. Das Material entstammt vorwiegend der Sprache der Kunst, der Grund dafür ist vor allem in der Tatsache zu suchen, daß in dieser Sprache dieser Form die Rolle eines natürlichen Kondensators zufällt, weshalb sie verhältnismäßig häufig vorkommt. Die Abhandlung befaßt sich eingehender auch mit dem Problem der Wortfolge und berührt auch die graphische Darstellung der bei der Prädikatsergänzung üblichen Pausen.

Energy transfer and thermal studies of Pr 3+ doped cerium oxalate ...

Indian Academy of Sciences (India)

The analysis of energy level diagrams of cerium and praseodymium ions indicates that the energy gap between the sensitizer and the activator ions varies in a small range suggesting a possible energy transfer from the Ce3+ to Pr3+. The emission and absorption spectra of these crystals were recorded. The overlapping of ...

Temperature dependence of colossal electro-resistance of Pr0.7Ca0.3MnO3 thin films

International Nuclear Information System (INIS)

Odagawa, A.; Kanno, T.; Adachi, H.; Sato, H.; Inoue, I.H.; Akoh, H.; Kawasaki, M.; Tokura, Y.

2005-01-01

The electronic conduction through a Pr 0.7 Ca 0.3 MnO 3 thin film is investigated by measurements using dc and pulsed bias. Pr 0.7 Ca 0.3 MnO 3 films sandwiched by electrodes exhibit two stable resistance states by means of applying voltage pulses. Both of the states show semiconducting behavior. The ratio of the two resistance states induces a colossal electro-resistance (CER) effect greater than 1000%. The CER behavior is seen in the temperature range of 300 K down to 150 K. The observed conduction characteristics exhibit the space-charge-limited-current effect, and the switching behavior can be ascribed to a carrier trapping/detrapping of the trap sites in the perovskite manganite

Le semis très précoce : une stratégie agronomique pour améliorer les performances du soja en France ?

Directory of Open Access Journals (Sweden)

Maury Pierre

2015-09-01

Full Text Available Le semis très précoce du soja a été étudié dans l’objectif d’améliorer le potentiel de rendement et/ou de réduire les besoins en eau. Trois variétés, appartenant à différents groupes de maturité, ont été retenues afin d’identifier les traits variétaux d’intérêt pour le semis très précoce. Un ensemble d’essais multilocaux, comportant deux modalités de semis avec irrigation, a été réalisé au cours de 5 années culturales (2010−2014. Le rendement et les besoins en eau ont été déterminés; un suivi dynamique du développement et de la croissance a été réalisé pour la variété Santana. Les effets combinés des basses températures et de la photopériode en réponse au semis précoce se traduisent par une production de biomasse aérienne réduite en phase végétative et une augmentation de la durée de remplissage des graines. Les valeurs maximales de rendement sont observées pour le semis très précoce, mais en moyenne le rendement est sensiblement plus faible en semis très précoce (3,7 t/ha vs. 3,9 t/ha. L’irrigation pour conduire les cultures dans des conditions proches de l’ETM a été sensiblement plus faible en semis très précoce (170 mm vs. 182 mm. Une variété tardive (groupe de maturité II apparaît mieux adaptée au semis très précoce qu’une variété de groupe de maturité I. Cette étude constitue une première référence agronomique d’évaluation du semis très précoce du soja et suggère que des types variétaux très tardifs pourraient améliorer le potentiel de rendement du soja en semis très précoce pour des conduites irriguées dans le Sud-Ouest de la France.

Structural aspects and the conduction mechanism of Ln(Ba{sub 2-x}Pr{sub x})Cu{sub 3}O{sub 7+{delta}} (Ln=Tm,Lu)

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, Z.; Akhavan, M. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran)

2007-09-15

TmBa{sub 2-x}Pr {sub x}Cu {sub 3}O {sub 7+{delta}} and LuBa {sub 2-x}Pr {sub x}Cu {sub 3}O {sub 7+{delta}} samples with 0.0 < x {<=} 1.0 have been prepared by a solid-state reaction technique. The occurrence of the orthorhombic to tetragonal phase transition, increasing of oxygen content with the increase of Pr doping, and the existence of solubility limit in both systems confirm the correct substitution of Pr at Ba sites. The solubility limit for Pr in the Lu-based samples is less than 0.7, which is less than x = 0.90 for the Tm-based samples. The T {sub c} depression versus doping content in both systems shows that depression of superconductivity by Pr at Ba sites is mostly due to the hole-filling/localization effects. Also, in the Tm-based system, the metal-insulator transition occurs at x {sub c}{sup MIT} {approx} 0.30, and the superconductor-insulator transition occurs at x {sub c}{sup SIT} = 0.45, but in the Lu-based system, x {sub c}{sup MIT} {approx} 0.35 and x {sub c}{sup SIT} = 0.50. In the normal state, for both systems with x < x {sub c}{sup MIT}, the Coulomb gap phase is dominant, whereas for the samples with Pr content x {sub c}{sup MIT} {<=} x < x {sub cc}{sup SIT}, two-dimensional variable-range hopping, and for x > x {sub c}{sup SIT}, three-dimensional variable-range hopping are the dominant conduction mechanisms. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Monoclinic superstructure of Pr{sub 3}Rh{sub 4}Ge{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Vosswinkel, Daniel; Hoffmann, Rolf-Dieter; Greiwe, Magnus; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2016-07-01

Pr{sub 3}Rh{sub 4}Ge{sub 4} was synthesized by melting of the elements in an arc-melting furnace followed by annealing in a sealed tantalum ampoule in a muffle furnace. Structure refinement was based on temperature dependent single-crystal X-ray diffractometer data. At ambient temperature Pr{sub 3}Rh{sub 4}Ge{sub 4} adopts the U{sub 3}Ni{sub 4}Si{sub 4} type structure with strongly enhanced anisotropic displacement parameters for Rh1. Below 230 K additional reflections start to appear and at 110 K the structure could be described with the (3+1)D superspace group I2/m(α0γ)00; α=1/2, γ=1/2; (Z=2). This commensurately modulated structure could be refined with 1448 F{sup 2} values, 39 variables and residuals of wR=0.0417 for the main reflections and wR=0.1520 for the satellites of 1{sup st} order, [a=408.36(2), b=421.12(3) and c=2504.4(2) pm]. The commensurate description could be transformed to a 3D supercell with space group A2/m and Z=4: a=816.72(2), b=421.12(3), c=2537.5(1) pm, β=99.26(1) , 1448 F{sup 2} values, 69 variables and wR=0.0499. The relation of the U{sub 3}Ni{sub 4}Si{sub 4} type structure, the (3+1)D modulated and the 3D supercell is discussed on the basis of a group-subgroup scheme. Temperature dependent magnetic susceptibility data reveal Curie-Weiss paramagnetism with an experimental moment of 3.72(2) μ{sub B}/Pr atom and a Weiss constant of -12.6(5) K. No magnetic ordering is evident down to 3 K.

Conversion of the thyroxin (T4) in 3,5,3'-triiodothyronin (T3) and 3,3',5'-triiodothyronin (T3 reverse) in human leukocytes suspensions. Hyperthyroidism and hypothyroidism studies

International Nuclear Information System (INIS)

Bianco, A.C.; Douglas, C.R.; Marone, M.M.; Scalissi, N.M.; Correa, P.H.S.

1984-01-01

The peripheral metabolism of thyroid hormones was studied in suspensions of human leukocytes through the evaluation of in vitro generation of T 3 and rT 3 (RIA) from non-radioactive T 4 . Increased in vitro generation of T 3 and rT 3 was observed in suspensions from hyperthyroid patients, while a significant decrease was evidenced when leukocytes from hypothyroid patients were used. These alterations are apparently due to the excess and lack of thyroid hormones, respectively, since they could be reserved in both cases by specific clinical treatment. (author) [pt

Specific heat of filled skutterudite PrOs4P12

International Nuclear Information System (INIS)

Matsuhira, Kazuyuki; Doi, Yoshihiro; Wakeshima, Makoto; Hinatsu, Yukio; Kihou, Kunihiro; Sekine, Chihiro; Shirotani, Ichimin

2005-01-01

We report the specific heat of filled skutterudite compounds PrOs 4 P 12 and LaOs 4 P 12 down to 1.8K. The specific heat divided by temperature C(T)/T in PrOs 4 P 12 shows a shoulder around 13K. This shoulder is caused by a Schottky anomaly due to a crystalline electric field effect. The electronic specific heat coefficients γ of PrOs 4 P 12 and LaOs 4 P 12 are estimated to be 56.5 and 21.6mJ/K 2 mol, respectively. The value of γ in PrOs 4 P 12 is 2.6 times larger than that in LaOs 4 P 12

Les présidents chinois et suisse visitent le CERN

CERN Multimedia

CERN Press Office. Geneva

1999-01-01

Le vendredi 26 mars 1999, Jiang Zemin, Président de la République populaire de Chine, et Ruth Dreifuss, Présidente de la Confédération suisse, ont visité le Laboratoire européen pour la physique des particules, le CERN . Ils ont été accueillis par le Directeur général, Luciano Maiani, sur les lieux de l'expérience L3. En 1985, Jiang Zemin, alors maire de Shanghai, avait contribué à organiser la production de cristaux de BGO à l'Institut de céramique de Shanghai, cristaux qui jouent aujourd'hui un rôle essentiel dans l'expérience L3

Conductivity and electrochemical characterization of PrFe1-xNixO3-δ at high temperature

DEFF Research Database (Denmark)

Hashimoto, Shin-Ichi; Kammer Hansen, Kent; Poulsen, Finn Willy

2007-01-01

PrFe(1-x)NixO(3)- (x=0.4-0.6) compounds were synthesized and characterized by powder XRD, electrical conductivity and electrochemical impedance spectroscopy on point electrodes on a Ce0.9Gd0.1O2-delta (CGO10) electrolyte. As a reference, the electrochemical performance of LaFe(0.4)AM(0.6)O(3-delta......) was also measured. The main phase in the PrFe1-xNixO3-delta series was perovskite-type structure and belonged to the orthorhombic crystal system. The conductivities are fairly high, e.g. around 220 S cm(-1) at 873 K for the x = 0.4 compound. The electrochemical performance of the PrFe(1-x)NixO(3-delta...

Anisotropic Transport and Magnetic Properties of Charge-Density-Wave Materials RSeTe_2 (R = La, Ce, Pr, Nd)

International Nuclear Information System (INIS)

Wang Pei-Pei; Long Yu-Jia; Zhao Ling-Xiao; Chen Dong; Xue Mian-Qi; Chen Gen-Fu

2015-01-01

Single crystals of RSeTe_2 (R = La, Ce, Pr, Nd) are synthesized using LiCl/RbCl flux. Transport and magnetic properties in the directions parallel and perpendicular to the a–c plane are investigated. We find that the resistivity anisotropy ρ_⊥/ρ_‖ lies in the range 486–615 for different compounds at 2 K, indicating the highly two-dimensional character. In both the orientations, the charge-density-wave transitions start near T_C_D_W = 284(3) K, 316(3) K, 359(3) K for NdSeTe_2, PrSeTe_2, CeSeTe_2, respectively, with a considerable increase in dc resistivity. While for LaSeTe_2, no obvious resistivity anomaly is observed up to 380 K. The value of T_C_D_W increases monotonically with the increasing lattice parameters. Below T_C_D_W, slight anomalies can be observed in NdSeTe_2, PrSeTe_2 and CeSeTe_2 with onset temperature at 193(3) K, 161(3) K, 108(3) K, respectively, decreasing as lattice parameters increase. Magnetic susceptibility measurements show that the valence state of rare earth ions are trivalence in these compounds. Antiferromagnetic-type magnetic order is formed in CeSeTe_2 at 2.1 K, while no magnetic transition is observed in PrSeTe_2 and NdSeTe_2 down to 1.8 K. (paper)

Luminescence and energy transfer in Lu3Al5O12 scintillators co-doped with Ce3+ and Pr3+

NARCIS (Netherlands)

Ogiegło, J.M.; Zych, A.K.; Jüstel, T.; Meijerink, A.; Ronda, R.C.

2013-01-01

Lu3Al5O12:Ce3+ (LuAG:Ce) is a scintillator with a fast response time. The light yield is lower than theoretically expected and to increase the light yield co-doping with Pr3+ is investigated. To better understand the energy flow to the Ce3+ ion, first low temperature emission and excitation spectra

Magnetic properties and structural transitions of fluorite-related rare earth osmates Ln3OsO7 (Ln=Pr, Tb)

International Nuclear Information System (INIS)

Hinatsu, Yukio; Doi, Yoshihiro

2013-01-01

Ternary rare-earth osmates Ln 3 OsO 7 (Ln=Pr, Tb) have been prepared. They crystallize in an ortho-rhombic superstructure of cubic fluorite with space group Cmcm. Both of these compounds undergo a structural phase transition at 130 K (Ln=Pr) and 580 K (Ln=Tb). These compounds show complex magnetic behavior at low temperatures. Pr 3 OsO 7 exhibits magnetic transitions at 8 and 73 K, and Tb 3 OsO 7 magnetically orders at 8 and 60 K. The Os moments become one-dimensionally ordered, and when the temperature is furthermore decreased, it provokes the ordering in the Ln 3+ sublattice that simultaneously becomes three-dimensionally ordered with the Os sublattice. - Graphical abstract: Ternary rare-earth osmates Ln 3 OsO 7 (Ln=Pr, Tb) have been prepared. They crystallize in an orthorhombic superstructure of cubic fluorite with space group Cmcm. Both of these compounds undergo a structural phase transition at 130 K (Ln=Pr) and 580 K (Ln=Tb). These compounds show complex magnetic behavior at low temperatures. Pr 3 OsO 7 exhibits magnetic transitions at 8 and 73 K, and Tb 3 OsO 7 magnetically orders at 8 and 60 K. Highlights: ► Ternary rare-earth osmates Ln 3 OsO 7 (Ln=Pr, Tb) with an ordered defect-fluorite structure have been prepared. ► Both of these compounds undergo a structural phase transition at 130 K (Ln=Pr) and 580 K (Ln=Tb). ► These compounds show complex magnetic behavior at low temperatures due to magnetic ordering of Ln and Os.

Synthesis and characterization of praseodymium-142 hydroxyapatite (142Pr-HA)

International Nuclear Information System (INIS)

Duyeh Setiawan; Daud Nurhasan

2015-01-01

The use of radioisotope of lanthanide group with range of beta energy 0.4 - 2.2 MeV has been renewed interest in nuclear medicine. Praseodymium-142 radioisotope ( 142 Pr, t 1/2 = 19.2 hours, E β = 2.16 MeV) is suitable for applications radiotherapy. Labelled of the hydroxyapatite (Ca 10 (PO 4 )6(OH) 2 ) can be used as carrier of radionuclide after injection in the body injection. This research aim as a preliminary studies to make praseodymium-142 hydroxyapatite ( 142 Pr-HA) as a radiotherapy agent. The optimum condition of praseodymium-142 hydroxyapatite synthesis by controlling several parameters such as the pH and the weight of hydroxyapatite was obtained from process by used the nonradioactive praseodymium. The optimum condition of hydroxyapatite by praseodymium are at pH 5 and weight ratio praseodymium : hydroxyapatite is 1 : 16. The percentage of labeling hydroxyapatite with 142 PrCl 3 was 99.50% and the radiochemical purity of 142 Pr-Ha was 95.20%. (author)

Pressure induced insulator–metal transition and giant negative piezoresistance in Pr{sub 0.6}Ca{sub 0.4}Mn{sub 0.96}Al{sub 0.04}O{sub 3} polycrystal

Energy Technology Data Exchange (ETDEWEB)

Arumugam, S., E-mail: sarumugam1963@yahoo.com [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu (India); Thiyagarajan, R. [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); Kalaiselvan, G.; Sivaprakash, P. [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirapalli 620024, Tamil Nadu (India)

2016-11-01

The effect of external hydrostatic pressure (P) on the magnetization (M) and resistivity (ρ) properties of charge-orbital (CO) ordered-insulating phase-separated manganite Pr{sub 0.6}Ca{sub 0.4}Mn{sub 0.96}Al{sub 0.04}O{sub 3} system is reported here. At ambient P, CO ordering transition and spin-canting in the AFM are observed at 223 K and 55 K respectively in M(T) and ρ(T) measurements. Application of P increases simultaneously the magnitude of magnetization (M) and transition temperature, and weakens the CO ordering in M(T) measurements up to 0.98 GPa. During ρ(T) measurements, P induces an insulator–metallic transition (T{sub IM}) at 1.02 GPa, and further increase of P up to 2.84 GPa leads to increase of T{sub IM} (dT{sub IM}/dP =21.6 K/GPa). ρ at T{sub IM} is reduced about three orders of magnitude at 2.84 GPa, and leads to the giant negative piezoresistance (~98%). These results are analyzed separately in two temperature regions i.e., below and above T{sub IM} by power function equation and small polaronic hopping model respectively. It is understood from these analyses that the application of P suppresses the Jahn–Teller distortions, electron–electron and electron–magnon scattering factors, and induces the insulator–metal transition in Pr{sub 0.6}Ca{sub 0.4}Mn{sub 0.96}Al{sub 0.04}O{sub 3} system. - Highlights: • Application of P on Pr{sub 0.6}Ca{sub 0.4}Mn{sub 0.96}Al{sub 0.04}O{sub 3} reduces resistivity (ρ) remarkably at low-temperatures, and exhibits an insulator to metallic transition at 1.02 GPa. • The reduction in ρ by P is about three orders of magnitude at 2.84 GPa, leads to the giant negative piezoresistance about 98%. • The effect of the suppression of Jahn–Teller distortions, electron–electron and electron–magnon scattering under an applied P exhibits to the metal-Insulator transition. • The phase-separation in this system has been tuned by both internal and external perturbations.

Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties

KAUST Repository

Mehdizadeh Dehkordi, Arash; Bhattacharya, Sriparna; Darroudi, Taghi; Zeng, Xiaoyu; Alshareef, Husam N.; Tritt, Terry M.

2015-01-01

We demonstrate a novel synthesis strategy for the preparation of Pr-doped SrTiO3 ceramics via a combination of solid state reaction and spark plasma sintering techniques. Polycrystalline ceramics possessing a unique morphology can be achieved by optimizing the process parameters, particularly spark plasma sintering heating rate. The phase and morphology of the synthesized ceramics were investigated in detail using X-ray diffraction, scanning electron microcopy and energy-dispersive X-ray spectroscopy It was observed that the grains of these bulk Pr-doped SrTiO3 ceramics were enhanced with Pr-rich grain boundaries. Electronic and thermal transport properties were also investigated as a function of temperature and doping concentration Such a microstructure was found to give rise to improved thermoelectric properties. Specifically, it resulted in a significant improvement in carrier mobility and the thermoelectric power factor. Simultaneously, it also led to a marked reduction in the thermal conductivity. As a result, a significant improvement (> 30%) in the thermoelectric figure of merit was achieved for the whole temperature range over all previously reported maximum values for SrTiO3-based ceramics. This synthesis demonstrates the steps for the preparation of bulk polycrystalline ceramics of non-uniformly Pr-doped SrTiO3.

Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties

KAUST Repository

Mehdizadeh Dehkordi, Arash

2015-08-15

We demonstrate a novel synthesis strategy for the preparation of Pr-doped SrTiO3 ceramics via a combination of solid state reaction and spark plasma sintering techniques. Polycrystalline ceramics possessing a unique morphology can be achieved by optimizing the process parameters, particularly spark plasma sintering heating rate. The phase and morphology of the synthesized ceramics were investigated in detail using X-ray diffraction, scanning electron microcopy and energy-dispersive X-ray spectroscopy It was observed that the grains of these bulk Pr-doped SrTiO3 ceramics were enhanced with Pr-rich grain boundaries. Electronic and thermal transport properties were also investigated as a function of temperature and doping concentration Such a microstructure was found to give rise to improved thermoelectric properties. Specifically, it resulted in a significant improvement in carrier mobility and the thermoelectric power factor. Simultaneously, it also led to a marked reduction in the thermal conductivity. As a result, a significant improvement (> 30%) in the thermoelectric figure of merit was achieved for the whole temperature range over all previously reported maximum values for SrTiO3-based ceramics. This synthesis demonstrates the steps for the preparation of bulk polycrystalline ceramics of non-uniformly Pr-doped SrTiO3.

The influence of post-preparation annealing atmospheres on the optical properties and energy transfer between Pr3+ and Dy3+ in mixed lanthanum-yttrium oxyorthosilicate hosts

Science.gov (United States)

Ogugua, Simon N.; Swart, Hendrik C.; Ntwaeaborwa, Odireleng M.

2018-02-01

The effect of post-annealing atmospheres (air and Ar-H2) on the optical properties of La2-xYxSiO5 (x = 0, 0.5, 1, 1.5 and 2) co-doped 0.25Pr3+ and 0.25Dy3+ powder phosphors were studied. The X-ray diffraction patterns showed that the as-prepared samples have higher full width at half maximum (FWHM) than the annealed samples. The elemental composition, oxidation states, and chemical and electronic states of the phosphors were determined using the X-ray photoelectron spectroscopy. The band gap values determined from the diffuse reflectance spectra were shown to increase following the post-annealing treatments (with the values increasing in the following manner: Ar-H2-annealed > air-annealed > as-prepared). The photoluminescence intensities of the phosphors also followed the same trend as the band gap values. Two different cases of the photoluminescence mechanisms were proposed for the La2-xYxSiO5:0.25Pr3+,0.25Dy3+ phosphors. Case 1: The 4f5d energy level of Pr3+ lies within the band gap of the host and energy transfer was observed from Pr3+ to Dy3+ via the overlapping 4f5d emission peak of Pr3+ and the 4I15/2 excitation peak of Dy3+. Case II: The 4f5d energy level of Pr3+ lies close or inside the conduction band of the host and the energy transfer was not observed from Pr3+ to Dy3+. The CIE colour coordinates of the phosphors showed tunable emission colours (blue, red and white).

Growth and luminescence properties of Pr3+-doped single crystalline films of garnets and perovskites

International Nuclear Information System (INIS)

Gorbenko, V.; Zorenko, Yu.; Savchyn, V.; Zorenko, T.; Pedan, A.; Shkliarskyi, V.

2010-01-01

Peculiarities of growth of single crystalline films (SCF) of Pr 3+ doped Y 3 Al 5 O 12 and Lu 3 Al 5 O 12 garnets and YAlO 3 and LuAlO 3 perovskites by the liquid phase epitaxy method from melt-solutions based on PbO-B 2 O 3 flux as well as luminescent and scintillation properties of these SCFs were studied in this work. Dependence the intensity of the Pr 3+ d-f and f-f-luminescence on the activator concentration and influence of Pb 2+ flux dopant on the light yield of SCFs of the mentioned garnets and perovskites were analyzed.

Electronic structure of PrBa2Cu3O7 within LSDA+U: Different self-consistent solutions

Directory of Open Access Journals (Sweden)

M R Mohammadizadeh

2009-08-01

Full Text Available  Based on the density functional theory and using the full-potential linearized augmented-plane-waves method the electronic structure of PrBa2Cu3O7 (Pr123 system was calculated. The rotationally invariant local spin density approximation plus Hubbard parameter U was employed for Pr(4f orbitals. One self-consistent solution more stable than the previous solution, which has been proposed by Liechtenstein and Mazin (LM, was found. In contrast to the LM solution, it can explain the results of the 17O NMR spectroscopy study of nonsuperconducting Pr123 samples. This new solution favors the suggestion that the pure Pr123 samples should be intrinsically superconductor and metal similar to the other RBa2Cu3O7 (R=Y or a rare earth element samples. The imperfections cause the superconducting holes are transferred to the nonsuperconducting hole states around the high-symmetry (π/a, π/b, kz line in the Brillouin zone and so, superconductivity is suppressed in the conventional samples. It predicts that the superconducting 2pσ holes in the O2 sites of nonsuperconducting Pr123 samples should be depleted and the ones in the O3 sites should be almost unchanged .

Sensitizing effects of ZnO quantum dots on red-emitting Pr3+-doped SiO2 phosphor

CSIR Research Space (South Africa)

Mbule, PS

2012-05-01

Full Text Available In this study, red cathodoluminescence (CL) ( emission=614 nm) was observed from Pr3+ ions in a glassy (amorphous) SiO2 host. This emission was enhanced considerably when ZnO quantum dots (QDs) were incorporated in the SiO2:Pr3+ suggesting...

A novel 3D nanoarchitecture of PrVO4 phosphor: Selective synthesis, characterization, and luminescence behavior

International Nuclear Information System (INIS)

Thirumalai, J.; Chandramohan, R.; Vijayan, T.A.

2011-01-01

Graphical abstract: Nanostructures of tetragonal PrVO 4 with novel 3D hierarchical architectures self-assembled nanorods were successfully synthesized by a hydrothermal method in ethylenediamine tetra-acetic acid (EDTA) mediated processes are ideal functional components for next generation luminescent devices. Research highlights: → Synthesis of self-assembled 3D nanoarchitecture of PrVO 4 phosphor. → Using template-free hydrothermal method. → pH, temperature and capping molecules control morphology of the products. → Detailed structural, morphology and luminescence were studied. - Abstract: Nanostructures of tetragonal PrVO 4 with novel 3D hierarchical architectures self-assembled nanorods were successfully synthesized by a hydrothermal method in ethylenediamine tetra-acetic acid (EDTA) mediated processes. Comprehensive structural, morphological studies like X-ray diffraction, scanning and transmission electron microscopy were employed to characterize the as-obtained products. In the hydrothermal process, EDTA not only acts as a chelating reagent to facilitate the formation of PrVO 4 , but also acts as a surface capping agent to adhere to the newly created surface and to promote the crystal splitting. The formation mechanisms of nanorods to hierarchical architectures were proposed on the basis of a series of surfactant and time-dependent experiments. Photoluminescence (PL) studies of PrVO 4 showed strong red emission upon UV illumination, and this implied potential application in the luminescent field. A possible growth mechanism of the sheaf-like PrVO 4 hierarchical nanocrystals is proposed and discussed.

Photoluminescence characteristics of Li-doped CaTiO{sub 3}:Pr{sup 3+} thin films grown on Si (100) substrate by PLD

Energy Technology Data Exchange (ETDEWEB)

Yang, Hyun Kyoung; Chung, Jong Won; Moon, Byung Kee; Choi, Byung Chun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of); Jeong, Jung Hyun, E-mail: jhjeong@pknu.ac.k [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of); Jang, Ki-wan; Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung Soo [Department of Electronic Materials Engineering, Silla University, Busan, 617-736 (Korea, Republic of); Kim, Kwang Ho [School of Materials Science and Engineering, Pusan National University, Busan, 609-735 (Korea, Republic of)

2010-09-01

The effects of Li-doped CaTiO{sub 3}:Pr{sup 3+} thin films have been investigated by varying the lithium ion concentrations from 0 to 5 wt.%. The films have been deposited on Si (100) substrate using a pulsed laser deposition technique. Structural properties of these films have been studied by the measurement of their XRD, SEM, and AFM. The variation of Li{sup +} concentration influences the crystallinity and surface morphology of the CaTiO{sub 3}:Pr{sup 3+} thin films. As Li{sup +} content increases from 0 to 1 wt.%, the crystallinity and intensity of emission increases. The dominant emission is from {sup 1}D{sub 2} {yields} {sup 3}H{sub 4} transition at 613 nm. The {sup 1}D{sub 2} emission quenching has also been observed in highly doped sample and is related to the cross-relaxation process between Pr{sup 3+} ions.

Formation of La3+, Pr3+, Eu3+, Er3+, and Lu3+ complexes with chloride ions, in aqueous medium

International Nuclear Information System (INIS)

Fernandez R, E.; Jimenez R, M.; Solache R, M.

2007-01-01

The constants of stability of the complexes of La 3+ , Pr 3+ , Eu 3+ , Er 3+ , and Lu 3+ with Cl - ions, its were determined, in the aqueous medium of HCI - HClO 4 and by a solvent extraction method. The dinonyl naphtalene sulfonic acid in n-heptane was used as extractant. The lanthanides concentration, it was measured by a VIS spectrophotometry method and by another radiochemical. The ions specific interaction theory (SIT) it was used for the extrapolation to ionic force 0 M. The results indicate that the stability constants of the LnCI 2+ species diminishes when increasing the ion force and the charge density. (Author)

Impact of larger rare earth Pr{sup 3+} ions on the physical properties of chemically derived Pr{sub x}CoFe{sub 2−x}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pachpinde, A.M.; Langade, M.M. [Department of Chemistry, Jawahar Art Science and Commerce College Andur, Osmanabad, MS (India); Lohar, K.S.; Patange, S.M. [Materials Research Laboratory, Srikrishna Mahavidyalaya Gunjoti, Omerga, Osmanabad 413 613, MS (India); Shirsath, Sagar E., E-mail: shirsathsagar@hotmail.com [Spin Device Technology Center, Department of Information Engineering, Shinshu University, Nagano 380 8553 (Japan)

2014-01-31

Highlights: • Rare earth Pr{sup 3+} substituted CoFe{sub 2}O{sub 4}. • Sol–gel auto combustion synthesis. • XRD and IR spectra reveal the spinel structure. • Magnetization and coercivity increased with Pr{sup 3+} substitution. - Abstract: Rare earth Pr{sup 3+} ions with its larger ionic radii substituted CoFe{sub 2}O{sub 4} nanoparticles with x ranging from 0.0 to 0.1 were synthesized by sol–gel auto-combustion chemical method. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR) and vibrating sample magnetometer (VSM) were employed to characterize the physical properties of these ferrite nanoparticles. XRD pattern reveals the formation of cubic spinel ferrite with the signature of PrFeO{sub 3} phases for x ⩾ 0.05. SEM images show that the synthesized samples are in good homogeneity with uniformly distributed grain. The results of IR spectroscopy analysis indicated that the functional groups of cobalt spinel ferrite were formed during the sol–gel process. The cations distribution between the tetrahedral (A-site) and octahedral sites (B-site) has been estimated by XRD analysis. Room temperature magnetic measurement shows saturation magnetization and coercivity increased from 54.7 to 64.2 emu/g and 644 to 1013 Oe, respectively with the increasing Pr{sup 3+} substitution.

Thermodynamic assessment of the Pr-Zn binary system

International Nuclear Information System (INIS)

Huang, X.M.; Liu, L.B.; Zhang, L.G.; Jia, B.R.; Jin, Z.P.; Zheng, F.

2008-01-01

On the basis of available experimental data of phase diagram and thermodynamic properties, the Pr-Zn binary system has been optimized using the CALPHAD approach. The phases, including liquid and bcc A 2(βPr) were treated as substitutional solutions, while the intermetallic compounds, including PrZn, PrZn 2 , PrZn 3 , Pr 3 Zn 11 , Pr 13 Zn 58 , Pr 3 Zn 22 , Pr 2 Zn 17 and PrZn 11 were modeled as stoichiometric compounds. As the result of optimization, a set of self-consistent thermodynamic parameters has been obtained, which can be used to reproduce the reported experimental data

Magnetotransport and magnetism in single-crystal PrBa2Cu3O7-δ

International Nuclear Information System (INIS)

Browning, V.M.; Osofsky, M.S.; Byers, J.M.; Ehrlich, A.C.; Dosseul, F.

1996-01-01

The PrBa 2 Cu 3 O 7-δ (Pr 123) system is known to exhibit antiferromagnetic ordering of the Cu spins in the Cu-O planes and chains, in addition to the observed antiferromagnetism due to the ordering of the Pr ions. The antiferromagnetism of the Cu-O planes is generally associated with the insulating nature of transport in Pr 123 and electrical conduction is believed to result through open-quote open-quote hopping close-quote close-quote transport between disordered Cu-O chain segments. However, the possible effects of magnetic ordering in the Cu-O chains on transport properties have not been discussed. If the Cu-O chains play a dominant role in the electrical transport (as suggested by many of the popular theories), then the magnetic ordering of the chains should also be seen in the transport properties. We present magnetization and magnetotransport measurements on single crystal Pr 123 samples which suggest that the magnetism associated with the Cu-O chains does indeed mediate transport in this system. These results confirm that the chains play a significant role in the transport properties and underscore the need for further study of the interplay between magnetism and transport in Pr 123

Practicality of the cyclotron production of radiolanthanide 142Pr. A potential for therapeutic applications and biodistribution studies

International Nuclear Information System (INIS)

Mahdi Sadeghi; Bakht, M.K.; Leila Mokhtari

2011-01-01

Radiolanthanide praseodymium-142 (T 1/2 = 19.12 h, E β - = 2.162 MeV (96.3%), E γ = 1575 keV (3.7%)) due to its high β-emission and low specific γ-emission could not only be a therapeutic radionuclide, but also a suitable radionuclide in order for biodistribution studies. Conventionally, 142 Pr produces via 141 Pr(n,γ) 142 Pr reaction by irradiation in a low-fluence reactor and this study evaluates cyclotron reaction production of it. 142 Pr excitation function via nat La(α,n) 142 Pr, 142 Ce(p,n) 142 Pr, and nat Pr(d,p) 142 Pr reactions were calculated by TALYS-1.2 and EMPIRE-2.19beta codes, and with the data taken from the TENDL-2010 database. In addition, we compared them with the reported measurement by experimental data. Requisite thickness of targets was obtained by SRIM-2010 code for each reaction. The 142 Pr production yield was evaluated with attention to excitation function and stopping power. Similar to reactor produced 142 Pr; 141 Pr impurity exists in cyclotron produced 142 Pr while it could not be separated by chemical methods. Therefore, cyclotron and reactor produced 142 Pr will be in carrier added form. (author)

PR-PR: cross-platform laboratory automation system.

Science.gov (United States)

Linshiz, Gregory; Stawski, Nina; Goyal, Garima; Bi, Changhao; Poust, Sean; Sharma, Monica; Mutalik, Vivek; Keasling, Jay D; Hillson, Nathan J

2014-08-15

To enable protocol standardization, sharing, and efficient implementation across laboratory automation platforms, we have further developed the PR-PR open-source high-level biology-friendly robot programming language as a cross-platform laboratory automation system. Beyond liquid-handling robotics, PR-PR now supports microfluidic and microscopy platforms, as well as protocol translation into human languages, such as English. While the same set of basic PR-PR commands and features are available for each supported platform, the underlying optimization and translation modules vary from platform to platform. Here, we describe these further developments to PR-PR, and demonstrate the experimental implementation and validation of PR-PR protocols for combinatorial modified Golden Gate DNA assembly across liquid-handling robotic, microfluidic, and manual platforms. To further test PR-PR cross-platform performance, we then implement and assess PR-PR protocols for Kunkel DNA mutagenesis and hierarchical Gibson DNA assembly for microfluidic and manual platforms.

Spectroscopic study of Pr3+ ions doped Zinc Lead Tungsten Tellurite glasses for visible photonic device applications

Science.gov (United States)

Sharma, Ritu; Rao, A. S.; Deopa, Nisha; Venkateswarlu, M.; Jayasimhadri, M.; Haranath, D.; Prakash, G. Vijaya

2018-04-01

Zinc Lead Tungsten Tellurite (ZnPbWTe) glasses doped with different Pr3+ ion concentrations having the composition 5ZnO + 15PbO + 20WO3 + (60-x)TeO2 + xPr6O11 (where x = 0.5, 1, 1.5, 2.0 and 2.5 mol%) were prepared by using sudden quenching technique and characterized to understand their visible emission characteristic features using spectroscopic techniques such as absorption, excitation and emission. The Judd-Ofelt (J-O) theory has been applied to the absorption spectral features with an aim to evaluate various radiative properties for the prominent fluorescent levels of Pr3+ions in the as-prepared glasses. The emission spectra recorded for the as-prepared glasses under 468 nm excitation show three prominent emission transitions 3P0→3H6, 3P0→3F2 and 3P1→3F4, of which 3P0→3F2 observed in visible red region (648 nm), is relatively more intense. The intensity of 3P0→3F2 emission transition in the titled glasses increases up to 1mol% of Pr3+ ions and beyond concentration quenching is observed. Branching ratios (βR) and emission cross-sections (σse) were estimated for 3P0→3F2 transition to understand the luminescence efficiency in visible red region (648 nm). The CIE chromaticity coordinates were also evaluated in order to understand the suitability of these glasses for visible red luminescence devices. From the emission cross-sections, quantum efficiency and CIE coordinates, it was concluded that 1mol% of Pr3+ ions in ZnPbWTe glasses are quite suitable for preparing visible reddish orange luminescent devices.

Isolation and characterization of NIH 3T3 cells expressing polyomavirus small T antigen

International Nuclear Information System (INIS)

Noda, T.; Satake, M.; Robins, T.; Ito, Y.

1986-01-01

The polyomavirus small T-antigen gene, together with the polyomavirus promoter, was inserted into retrovirus vector pGV16 which contains the Moloney sarcoma virus long terminal repeat and neomycin resistance gene driven by the simian virus 40 promoter. This expression vector, pGVST, was packaged into retrovirus particles by transfection of PSI2 cells which harbor packaging-defective murine retrovirus genome. NIH 3T3 cells were infected by this replication-defective retrovirus containing pGVST. Of the 15 G418-resistant cell clones, 8 express small T antigen at various levels as revealed by immunoprecipitation. A cellular protein with an apparent molecular weight of about 32,000 coprecipitates with small T antigen. Immunofluorescent staining shows that small T antigen is mainly present in the nuclei. Morphologically, cells expressing small T antigen are indistinguishable from parental NIH 3T3 cells and have a microfilament pattern similar to that in parental NIH 3T3 cells. Cells expressing small T antigen form a flat monolayer but continue to grow beyond the saturation density observed for parental NIH 3T3 cells and eventually come off the culture plate as a result of overconfluency. There is some correlation between the level of expression of small T antigen and the growth rate of the cells. Small T-antigen-expressing cells form small colonies in soft agar. However, the proportion of cells which form these small colonies is rather small. A clone of these cells tested did not form tumors in nude mice within 3 months after inoculation of 10 6 cells per animal. Thus, present studies establish that the small T antigen of polyomavirus is a second nucleus-localized transforming gene product of the virus (the first one being large T antigen) and by itself has a function which is to stimulate the growth of NIH 3T3 cells beyond their saturation density in monolayer culture

Study of magnetic properties of TGa6 with T = Ce, Pr, Nd, Tb, Ho, Dy and of solid solutions Ce(Ga1-x Alx)2

International Nuclear Information System (INIS)

Jerjini, M.

1987-10-01

At low temperature TGa 6 compounds are ordered with a Neel temperature of about 10 K. Magnetic structures are antiferromagnetic for T = Pr or Nd or modulated for T = Tb, Ho or Dy. Ce presents an abnormal behavior in CeGa 6 . Neutron inelastic scattering allows the determination of energy levels in the crystal field of cerium ion and evidences hybridation of 4f and valence electrons. Three magnetic transitions for T 6 . Study of CeGa 6 and solid solutions. Ce(Ga (1-x) Al x ) 2 shows that aluminium insertion reinforces the Kondo effect. For x = O.1 an incommensurable structure subsists at very low temperature. CeGa 2 is ordered with 3 magnetic structures. Magnetic moment is reduced with Al. The study of crystal field by neutron scattering shows that hybridation effects are more important for the compound with x = 0.1 [fr

Mononuclear Amido and Binuclear Imido Zirconium Complexes Supported by Dibenzotetraaza[14]annulene Ligands. X-ray Structure of [(Me(4)taa)Zr(&mgr;-NR)(2)Zr(NHR)(2)] (R = Bu(t) or 2,6-C(6)H(3)Me(2)).

Science.gov (United States)

Nikonov, Georgii I.; Blake, Alexander J.; Mountford, Philip

1997-03-12

Reaction of 2 equiv of Li[NH-2,6-C(6)H(3)R(2)] with [(Me(4)taa)ZrCl(2)] (Me(4)taaH(2) = tetramethyldibenzotetraaza[14]annulene) gives the bis(amido) derivatives [(Me(4)taa)Zr(NH-2,6-C(6)H(3)R(2))(2)] [R = Pr(i) (1) and Me (2)]. Addition of Me(4)taaH(2) to [Zr(N-2,6-C(6)H(3)Pr(i)(2))(NH-2,6-C(6)H(3)Pr(i)(2))(2)(py)(2)] also affords 1. The reaction of 2 equiv of aryl or alkyl amines H(2)NR with the bis(alkyl) complex [(Me(4)taa)Zr(CH(2)SiMe(3))(2)] is the most versatile method for preparing [(Me(4)taa)Zr(NHR)(2)] (R = 2,6-C(6)H(3)Pr(i)(2), 2,6-C(6)H(3)Me(2), Ph, or Bu(t)). Reaction of 1 equiv of Me(4)taaH(2) with the binuclear complexes [(Bu(t)NH)(2)Zr(&mgr;-NBu(t))(2)Zr(NHBu(t))(2)] or [(py)(HN-2,6-C(6)H(3)Me(2))(2)Zr(&mgr;-N-2,6-C(6)H(3)Me(2))(2)Zr(NH-2,6-C(6)H(3)Me(2))(2)(py)] gives the asymmetrically substituted derivatives [(Me(4)taa)Zr(&mgr;-NR)(2)Zr(NHR)(2)] [R = Bu(t) (6) or 2,6-C(6)H(3)Me(2) (8)], which have been crystallographically characterized.

Molecular insights on analogs of HIV PR inhibitors toward HTLV-1 PR through QM/MM interactions and molecular dynamics studies: comparative structure analysis of wild and mutant HTLV-1 PR.

Science.gov (United States)

Selvaraj, Chandrabose; Singh, Poonam; Singh, Sanjeev Kumar

2014-12-01

Retroviruses HTLV-1 and HIV-1 are the primary causative agents of fatal adult T-cell leukemia and acquired immune deficiency syndrome (AIDS) disease. Both retroviruses are similar in characteristics mechanism, and it encodes for protease that mainly involved in the viral replication process. On the basis of the therapeutic success of HIV-1 PR inhibitors, the protease of HTLV-1 is mainly considered as a potential target for chemotherapy. At the same time, structural similarities in both enzymes that originate HIV PR inhibitors can also be an HTLV-1 PR inhibitor. But the expectations failed because of rejection of HIV PR inhibitors from the HTLV-1 PR binding pocket. In this present study, the reason for the HIV PR inhibitor rejection from the HTLV-1 binding site was identified through sequence analysis and molecular dynamics simulation method. Functional analysis of M37A mutation in HTLV PR clearly shows that the MET37 specificity and screening of potential inhibitors targeting MET37 is performed by using approved 90% similar HIV PR inhibitor compounds. From this approach, we report few compounds with a tendency to accept/donate electron specifically to an important site residue MET37 in HTLV-1 PR binding pocket. Copyright © 2014 John Wiley & Sons, Ltd.

Superconductivity and spin gap in the zigzag-chain t-J model simulating a CuO double chain in Pr2Ba4Cu7O15-δ

International Nuclear Information System (INIS)

Sano, Kazuhiro; Ono, Yoshiaki

2007-01-01

Using the numerical diagonalization method, we examine the one-dimensional t 1 -t 2 -J 1 -J 2 model (zigzag-chain t-J model) which is an effective model for metallic CuO double chains in the super-conductor Pr 2 Ba 4 Cu 7 O 15-δ . Based on the Tomonaga-Luttinger liquid theory, we calculate the Luttinger liquid parameter K ρ as a function of the electron density n. It is found that superconductivity is realized in the parameter region, which is in accordance with experimental results. We show the phase diagram of a spin gap in the t 2 /|t 1 |-n plane by analyzing the expectation value of the twist operator Z σ in the spin sector. The spin gap appears in the region with a large t 2 /|t 1 |, where the phase boundary at half filling is consistent with that of the known frustrated quantum spin system. The analysis also suggests that the estimated value of the spin gap reaches ∼100 K in the realistic parameter region of Pr 2 Ba 4 Cu 7 O 15-δ . (author)

Phase diagrams of Pr-C system

International Nuclear Information System (INIS)

Eremenko, V.N.; Velikanova, T.Ya.; Gordijchuk, O.V.

1988-01-01

Results of the X-ray phase, metallographic and high-temperature differential thermal analysis are used for the first time to plot a diagram of the Pr-C system state. Carbides are formed in the system: Pr 2 C 3 with the bcc-structure of the Pu 2 C 3 type and with the period a 0 = 0.85722+-0.00026 within the phase region + 2 C 3 >, a 0 0.86078+-0.00016 nm - within the region 2 C 3 >+α-PrC 2 ; dimorphous PrC 2 : α-PrC 2 with the bct-structure of the CaC 2 type and periods a 0.38517+-0.00011, c 0 = 0.64337+-0.00019 nm; β-PrC 2 with the fcc-structure, probably, of KCN type. Dicarbide melts congruently at 2320 grad. C, forming eutectics with graphite at 2254+-6 grad. C and composition of 71.5% (at.)C. It is polymorphously transformed in the phase region 2 C 3 > + 2 > at 1145+-4 grad. C, and in the region 2 >+C at 1134+-4 grad. C. Sesquicarbide melts incongruently at 1545+-4 grad. C. The eutectic reaction L ↔ + 2 C 3 > occurs at 800+-4 grad. C, the eutectic composition ∼ 15% (at.)C. The temperature of the eutectoid reaction ↔ + 2 C 3 > is 675+-6 grad C. The limiting carbon solubility in β-Pr is about 8 and in α-Pr it is about 5% (at.)

Magnetic properties of cyano-bridged Ln3+-M3+ complexes. Part I: trinuclear complexes (Ln3+ = La, Ce, Pr, Nd, Sm; M3+ = FeLS, Co) with bpy as blocking ligand.

Science.gov (United States)

Figuerola, Albert; Ribas, Joan; Llunell, Miquel; Casanova, David; Maestro, Miguel; Alvarez, Santiago; Diaz, Carmen

2005-10-03

The reaction of Ln(NO3)3(aq) with K3[Fe(CN)6] or K3[Co(CN)6] and 2,2'-bipyridine in water/ethanol led to eight trinuclear complexes: trans-[M(CN)4(mu-CN)2{Ln(H2O)4(bpy)2}2][M(CN)6].8H2O (M = Fe3+ or Co3+, Ln = La3+, Ce3+, Pr3+, Nd3+, and Sm3+). The structures for the eight complexes [La2Fe] (1), [Ce2Fe] (2), [Pr2Fe] (3), [Nd2Fe] (4), [Ce2Co] (5), [Pr2Co] (6), [Nd2Co] (7), and [Sm2Co] (8) have been solved; they crystallize in the triclinic space group P and are isomorphous. They exhibit a supramolecular 3D architecture through hydrogen bonding and pi-pi stacking interactions. A stereochemical study of the nine-vertex polyhedra of the lanthanide ions, based on continuous shape measures, is presented. No significant magnetic interaction was found between the lanthanide(III) and the iron(III) ions.

Mid-infrared emissions of Pr{sup 3+}-doped GeS{sub 2}–Ga{sub 2}S{sub 3}–CdI{sub 2} chalcohalide glasses

Energy Technology Data Exchange (ETDEWEB)

Lu, Chunfeng [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and precision Mechanics, Chinese Academy of Science (CAS), Xi’an, Shaanxi 710119 (China); Guo, Haitao, E-mail: guoht_001@opt.ac.cn [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and precision Mechanics, Chinese Academy of Science (CAS), Xi’an, Shaanxi 710119 (China); Xu, Yantao; Hou, Chaoqi; Lu, Min [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and precision Mechanics, Chinese Academy of Science (CAS), Xi’an, Shaanxi 710119 (China); He, Xin [School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020 (China); Wang, Pengfei; Li, Weinan [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and precision Mechanics, Chinese Academy of Science (CAS), Xi’an, Shaanxi 710119 (China); Peng, Bo, E-mail: bpeng@opt.ac.cn [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and precision Mechanics, Chinese Academy of Science (CAS), Xi’an, Shaanxi 710119 (China)

2014-12-15

Graphical abstract: ∼4.6 μm mid-infrared fluorescence emission from Pr{sup 3+} in the sulfide glass is successfully observed at room temperature excited by a 2.01 μm Tm{sup 3+}:YAG ceramic laser system. - Highlights: • Serial Pr{sup 3+}-doped GeS{sub 2}–Ga{sub 2}S{sub 3}–CdI{sub 2} chalcohalide glasses were synthesized. • ∼4.6 μm mid-infrared fluorescence from Pr{sup 3+} was observed at room temperature. • The compositional dependence of luminescence properties was studied. • Radiative properties have been determined using the Judd–Ofelt theory. - Abstract: For elucidation of the glass composition’s influence on the spectroscopic properties in the chalcohalide system and the discovery of a new material for applications in mid-infrared fiber-lasers, a serial Pr{sup 3+}-doped (100 − x)(0.8GeS{sub 2}·0.2Ga{sub 2}S{sub 3})xCdI{sub 2} (x = 5, 10, 15 and 20) chalcohalide glasses were prepared. ∼4.6 μm mid-infrared fluorescence emission from Pr{sup 3+} in the sulfide glass is successfully observed at room temperature excited by a 2.01 μm Tm{sup 3+}:YAG ceramic laser system, and the effective line-width of fluorescence band is 106–227 nm. Intense compositional dependence of mid-infrared emissions is found. The radiative rates of Pr{sup 3+} ions in these glasses were calculated by using the Judd–Ofelt theory.

Próteses psíquicas: a psicofarmacologia como biotecnologia e a téchne trágica da psicanálise

Directory of Open Access Journals (Sweden)

Glaucia Dunley

Full Text Available Considerando a relevância do estudo das próteses na cultura informacional contemporânea, e aproximando-o do campo psicopatológico através da idéia dos psicofármacos funcionando como próteses psíquicas, pretendo problematizar a inserção das novas tecnologias – especialmente as biotecnologias, como a psicofarmacologia – no projeto de longa duração da metafísica, descortinando a lógica da vontade de poder em jogo, e suas máscaras. Procurando formas de resistir a esta disponibilização sem fim do real, pela qual o próprio sujeito se vê atingido, objetivando-se das mais variadas formas, a psicanálise se configura como téchne trágica, herdeira de uma transmissão estética e ética da existência, propondose a restituir ao homem contemporâneo um saber sobre a sua própria tragicidade, pela qual seria possível afirmar um bem-viver em que a dor de existir não ficaria encoberta.

Manual de la práctica 3 de laboratorio 2010 (revisado)

OpenAIRE

Candelas Herías, Francisco Andrés; Puente Méndez, Santiago Timoteo

2010-01-01

Esta versión del manual ha sido actualizada y revisada, y tiene varios errores corregidos. Manual de la práctica 3 de laboratorio sobre gestión de la Calidad de Servicio con routers Cisco y análisis de redes IEEE 802.11, para el curso 2009-10.

Dual-enhancement of ferro-/piezoelectric and photoluminescent performance in Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Wei, Yongbin; Jia, Yanmin, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn; Wu, Jiang; Shen, Yichao [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

2014-07-28

A mutual enhancement action between the ferro-/piezoelectric polarization and the photoluminescent performance of rare earth Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} (KNN) lead-free ceramics is reported. After Pr{sup 3+} doping, the KNN ceramics exhibit the maximum enhancement of ∼1.2 times in the ferroelectric remanent polarization strength and ∼1.25 times in the piezoelectric coefficient d{sub 33}, respectively. Furthermore, after undergoing a ferro-/piezoelectric polarization treatment, the maximum enhancement of ∼1.3 times in photoluminescence (PL) was observed in the poled 0.3% Pr{sup 3+} doped sample. After the trivalent Pr{sup 3+} unequivalently substituting the univalent (K{sub 0.5}Na{sub 0.5}){sup +}, A-sites ionic vacancies will occur to maintain charge neutrality, which may reduce the inner stress and ease the domain wall motions, yielding to the enhancement in ferro-/piezoelectric performance. The polarization-induced enhancement in PL is attributed to the decrease of crystal symmetry abound the Pr{sup 3+} ions after polarization. The dual-enhancement of the ferro-/piezoelectric and photoluminescent performance makes the Pr{sup 3+} doped KNN ceramic hopeful for piezoelectric/luminescent multifunctional devices.

Pr{sub 3}S{sub 2}Cl{sub 2}[AsS{sub 3}]: a praseodymium(III) sulfide chloride thioarsenate(III) with double chains of condensed [SPr{sub 4}]{sup 10+} tetrahedra

Energy Technology Data Exchange (ETDEWEB)

Kang, Dong-Hee [Institute for Inorganic Chemistry, University of Stuttgart (Germany); Department of Chemistry, University of Waterloo, ON (Canada); Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Ledderboge, Florian; Schleid, Thomas [Institute for Inorganic Chemistry, University of Stuttgart (Germany); Kleinke, Holger [Department of Chemistry, University of Waterloo, ON (Canada)

2015-02-15

Single crystals of Pr{sub 3}S{sub 2}Cl{sub 2}[AsS{sub 3}] were obtained by reacting praseodymium sesquisulfide and trichloride with arsenic and sulfur (molar ratio: 7:4:6:9) in torch-sealed evacuated silica ampoules at 850 C for a week and subsequent slow cooling to room temperature. The transparent, pale yellowish green platelets crystallize monoclinically (Pr{sub 3}S{sub 2}Cl{sub 2}[AsS{sub 3}]: a = 2190.96(9) pm, b = 685.49(3) pm, c = 701.87(3) pm, β = 98.752(3) ) in the non-centrosymmetric space group Cc with Z = 4. The crystal structure of Pr{sub 3}S{sub 2}Cl{sub 2}[AsS{sub 3}] comprises three crystallographically different Pr{sup 3+} cations. (Pr1){sup 3+} and (Pr2){sup 3+} exhibit bicapped trigonal prismatic environments of five sulfur and three chlorine atoms (C.N. = 8) each, whereas only seven sulfur atoms arranged as capped trigonal prism (C.N. = 7) are present in the case of (Pr3){sup 3+}. Two of the five crystallographically different sulfur atoms (S1 and S2) are coordinated by four Pr{sup 3+} cations, each in the shape of slightly distorted [SPr{sub 4}]{sup 10+} tetrahedra (d(S-Pr) = 278-294 pm). Hence, the crystal structure of Pr{sub 3}S{sub 2}Cl{sub 2}[AsS{sub 3}] contains double chains with the composition {sup 1}{sub ∞}{[S_2Pr_3]"5"+}, consisting of two parallel edge-fused chains of anti-SiS{sub 2}-analogous single strands {sup 1}{sub ∞}{[SPr_2]"4"+}, formed by trans-edge sharing [SPr{sub 4}]{sup 10+} tetrahedra. The arrangement of the {sup 1}{sub ∞}{[S_2Pr_3]"5"+} double chains running along [001] can be described as a hexagonal rod-packing. Chloride anions (Cl1 and Cl2) as well as the isolated, ψ{sup 1}-tetrahedral thioarsenate(III) groups [AsS{sub 3}]{sup 3-} (d(As-S) = 228-229 pm) consisting of three sulfur atoms (S3, S4, and S5) and an As{sup 3+} cation carrying a stereochemically active non-bonding electron pair take care of the three-dimensional interconnection and the charge balance of the {sup 1}{sub ∞}{[S_2Pr_3]"5"+} double

A potential method using Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2}, (Et{sub 3}Si){sub 2}Te and anhydrous hydrazine for germanium tellurides

Energy Technology Data Exchange (ETDEWEB)

Du, Liyong; Du, Shulei; Ding, Yuqiang [School of Chemical and Material Engineering, Jiangnan University, Wuxi (China)

2017-12-29

A germanium(II)-guanidine derivative of formula Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2} (1) was synthesized and characterized by {sup 1}H NMR, {sup 13}C NMR, elemental analysis, and X-ray diffraction method. Thermal property was also studied to identify its thermal stability and volatility. More importantly, compound 1 was synthesized to develop a new method for germanium tellurides, where anhydrous hydrazine was introduced to prompt the activity of germanium(II) guanidines (or derivatives) towards (Et{sub 3}Si){sub 2}Te. Solution reaction of compound 1, (Et{sub 3}Si){sub 2}Te, and anhydrous hydrazine was investigated to pre-identify the feasibility of this combination for ALD process. The EDS data of the black precipitate from this reaction verified the potential of this method to manufacture germanium tellurides. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Accumulation of a Hot Ion Plasma in PR-5; Accumulation d'un Plasma a Ions Chauds dans l'Installation PR-5; Nakoplenie plazmy s goryachimi ionami na ustanovke PR-5; Acumulacion de un Plasma con Iones Calientes en la Instalacion PR-5

Energy Technology Data Exchange (ETDEWEB)

Gott, Ju. V.; Ioffe, M. S.; Jushmanov, E. E. [Institut Atomnoj Ehnergii Im. I.V. Kurchatova, Moskva, SSSR (Russian Federation)

1966-04-15

In earlier experiments on PR-5 it was shown that in a trap with magnetic mirrors the flute instability is completely suppressed when a radially increasing hybrid magnetic field (minimum-H trap) is set up. In those experiments a hydrogen plasma with hot ions (T{sub i} Asymptotically-Equal-To 5 keV) and density n up to 10{sup 10} cm{sup -3} was produced by the magnetron injection method; the confinement time T was equal to several tens of milliseconds, and was determined only by charge-exchange losses. The effect of the suppression of the flute instability was also observed by several others, although it is not possible on the basis of present results to draw conclusions about the stability of the plasma for densities considerably in excess of 10{sup 10} cm{sup -3}. Biguet et al. for n = 10{sup 13} to 10{sup 14} cm{sup -3} report {tau} = 60 {mu}sec; in the authors' view, this small {tau} is attributable to the charge-exchange of fast ions on the neutral gas desorbing from the walls during the injection. We explored the possibility of achieving prolonged containment of the plasma at densities n {>=} 10{sup 11} cm{sup -3} and T{sub i} {>=} 5 keV. The experimental study of the behaviour of such a plasma presents considerable interest in view of the theory of Mikhailovsky and Timofeev predicting at these n and T{sub i} values the drift-cyclotron instability. This instability, which is due to a radial inhomogeneity of the plasma density, must occur on the condition that ({rho}/a){sup 2} > 4[(H{sup 2}/4{pi}m{sub i}c{sup 2}) + (m{sub e}/m{sub i})] where {rho}i is the ion Larmor radius and a is a characteristic length of the inhomogeneity. For typical conditions in PR-5 (H = 4000 Oe, {rho}{sub i}/a Asymptotically-Equal-To 0.25), this criterion is fulfilled starting from n Asymptotically-Equal-To 5 x 10{sup 10} cm{sup -3}. To obtain a plasma with such parameters a modified magnetron injection method is used in which the ions are accelerated from the cold plasma column by a

Locoregional deformation pattern of the patellar cartilage after different loading types. High-resolution 3D-MRI volumetry at 3 T in-vivo

International Nuclear Information System (INIS)

Horng, Annie; Raya, J.; Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Grosshadern; Zscharn, M.

2011-01-01

Purpose: To analyze locoregional deformation patterns indicative of contact areas in patellar cartilage after different loading exercises. Materials and Methods: 7 healthy patellae were examined in-vivo before and immediately after standardized loading (kneeling, squatting or knee bends) and after 90 minutes of rest using a sagittal 3D-T1-w FLASH WE sequence (22 msec/ 9.8msec/ 15 / 0.3 x 0.3 x 1.5 mm 3 ) at 3 T. After cartilage segmentation and 3D reconstruction, voxel-based and global precision errors (PR) were calculated. The former were used to determine significant differences in local cartilage thickness. Voxel-based 2σ-thickness difference maps were calculated to visualize locoregional deformation patterns. Global changes in volume (Vol), mean thickness (mTh) and cartilage-bone-interface area (CBIA) were calculated. Results: The voxel-based PR depended on cartilage thickness (D) ranging from 0.12 - 0.35 mm. For D ≥ 1 mm the RF was 3 (2.4 %) for Vol, 0.06 mm (2.0 %) for mTh and 16 mm 2 (1.4 %) for CBIA. The focal cartilage deformation equaled 14 % of the local thickness reduction. The deformation areas were oval and located in the peripheral medial (more vertically oriented, all exercises) and caudo-lateral (more horizontally oriented, kneeling and knee bends) aspects of the patella and were least pronounced in knee bends. Significant changes for Vol/mTh ranged from 2.1 to 3.7 %. Conclusion: This MRI-based study is the first to identify in-vivo voxel-based patellar cartilage deformation patterns indicating contact and loading zones after kneeling and squatting. These zones are anatomically and functionally plausible and may represent areas where stress induced degeneration and subsequent OA can originate. The data may facilitate understanding of individual knee loading properties and help to improve and validate biomechanical models for the knee. (orig.)

Relaxation of the electronic states at a thin-layer YBa2Cu 3O7/PrBa2Cu3O7 interface

KAUST Repository

Gó mez, Javier Alexandra M; Larkin, Ivan A.; Schwingenschlö gl, Udo

2010-01-01

We discuss in detail spin-polarized electronic structure calculations for the 1 × 1 YBa2Cu3O7/PrBa 2Cu3O7 superlattice. Our results are based on the full-potential linear augmented plane wave method and the generalized gradient approximation for the exchange-correlation functional. The on-site Coulomb interaction affecting the correlated Cu 3d and Pr 4f electrons is taken into consideration. At first glance the YBa2Cu3O 7/PrBa2Cu3O7 interface appears to be inert, i.e., the electronic states do not show a clear sign of interaction between the two component materials. Nonetheless, a total energy analysis points to a significant modification of the magnetic coupling in the vicinity of the interface due to the relaxation of the electronic structure. © 2010 Elsevier B.V. All rights reserved.

Relaxation of the electronic states at a thin-layer YBa2Cu 3O7/PrBa2Cu3O7 interface

KAUST Repository

Gómez, Javier Alexandra M

2010-11-01

We discuss in detail spin-polarized electronic structure calculations for the 1 × 1 YBa2Cu3O7/PrBa 2Cu3O7 superlattice. Our results are based on the full-potential linear augmented plane wave method and the generalized gradient approximation for the exchange-correlation functional. The on-site Coulomb interaction affecting the correlated Cu 3d and Pr 4f electrons is taken into consideration. At first glance the YBa2Cu3O 7/PrBa2Cu3O7 interface appears to be inert, i.e., the electronic states do not show a clear sign of interaction between the two component materials. Nonetheless, a total energy analysis points to a significant modification of the magnetic coupling in the vicinity of the interface due to the relaxation of the electronic structure. © 2010 Elsevier B.V. All rights reserved.

Modelling the optical bleaching of the thermoluminescence of K2YF5:Pr3+

International Nuclear Information System (INIS)

Marcazzó, J.; Santiago, M.; Khaidukov, N.; Caselli, E.

2012-01-01

Optical bleaching of the thermoluminescence (TL) curve of K 2 YF 5 :Pr 3+ has been observed after optically stimulated luminescence (OSL) readout of pre-irradiated crystals. The traps being responsible for the TL signal are not emptied completely by the optical stimulation. Furthermore, if the illumination time is increased a constant intensity level of the residual TL glow curve is eventually achieved. On the other hand, if the low temperature peak of the glow curve is thermally cleaned, no subsequent OSL is measured. This behavior has been successfully explained by assuming that part of the electrons in the trap being responsible for the low temperature glow peak of K 2 YF 5 :Pr 3+ recombine with holes via localized transitions during optical stimulation. During TL all trapped electrons recombine via delocalized transitions. Simulations have been carried out in order to demonstrate the feasibility of the model. - Highlights: ► The optical bleaching of the thermoluminescence of K2YF5:Pr 3+ has been studied. ► A model accounting for the optical bleaching has been put forward. ► Thermoluminescence occurs via delocalized transitions. ► Localized transitions occur during optical stimulation.

Controllable synthesis and tunable luminescence of glass ceramic containing Mn2+:ZnAl2O4 and Pr3+:YF3 nano-crystals

International Nuclear Information System (INIS)

Yu, Yunlong; Li, Xiaoyan

2016-01-01

Highlights: • Glass ceramic containing ZnAl 2 O 4 and YF 3 nano-crystals is fabricated. • Mn 2+ and Pr 3+ are selectively incorporated into ZnAl 2 O 4 and YF 3 , respectively. • The luminescence color can be tuned by adjusting the excitation wavelength. - Abstract: Glass ceramic containing spinel ZnAl 2 O 4 :Mn 2+ and orthorhombic YF 3 :Pr 3+ nano-crystals has been successfully prepared by a melt-quenching technique. X-ray diffraction and transmission electron microscopy demonstrated that two nano-phases, i.e. ZnAl 2 O 4 and YF 3 , were homogeneously distributed among the glass matrix. Importantly, the selective incorporation of Pr 3+ ions into the Y 3+ nine-fold coordinated sites of YF 3 and the segregation of Mn 2+ dopants in the Zn 2+ tetrahedral sites of ZnAl 2 O 4 were confirmed based on the excitation/emission spectra and the crystal field calculation. Under blue light excitation, both Pr 3+ and Mn 2+ in the glass ceramic can be simultaneously excited, and emit red and green luminescence, respectively, owing to the suppression of energy transfer between them. The luminescence color of the obtained glass ceramic can be easily tuned by adjusting the excitation wavelength. These results indicate the potential application of the glass ceramic as converting phosphor to generate white-light after coupling with the blue LED chip.

Study of absorption, emission and EDS properties of Pr3+ incorporated in a SiO2 matrix by sol-gel method

International Nuclear Information System (INIS)

Gómez-Miranda, M; Fonseca, R Sosa; Ordoñez, C Velásquez

2015-01-01

The optical response of the Pr 3+ ions doped monolith of SiO 2 prepared by sol-gel method was investigated by absorption and emission spectra. The absorption spectrum shows some typical lines of Pr 3+ , with these data was made the diagram levels corresponding to SiO 2 : Pr 3+ . The emission spectra were taken at 225 nm and 240 nm of wavelength of excitation was measured. In that there are reabsorption line at 423 of the Pr 3+ ions in the emission host, that means that some kind of host-ion interactions exist. Red and NIR emission at 612 nm, 652 nm, 711 and 728 nm, respectively, from Pr 3+ ions in SiO 2 was observed. The transition 1 S 0 → 3 P 2 at 425 nm is observed because an effective radiative transfer between the silicate glasses host and the praseodymium ions is observed and discussed

Electronic structures of PrBa{sub 2}Cu{sub 3}O{sub 7}, Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-y}(y=0,1), and PrBa{sub 2}Cu{sub 4}O{sub 8} based on LSDA+U method

Energy Technology Data Exchange (ETDEWEB)

Tavana, A. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, Tehran (Iran); Department of Physics, University of Mohaghegh Ardabili, Ardabil (Iran); Shirazi, M.; Akhavan, M. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, Tehran (Iran)

2009-10-15

The electronic structures of PrBa{sub 2}Cu{sub 3}O{sub 7} (Pr123), Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-y} (Pr247), and PrBa{sub 2}Cu{sub 4}O{sub 8} (Pr124) cuprates have been obtained using density-functional theory in the local spin density approximation plus onsite Coulomb interaction (LSDA+U). Onsite Hubbard correlation, U, has been considered for Pr-f and Cu-d orbitals and the effects of considering these correlation corrections on the Pr-O hybridizations have been inspected. Results imply that the Pr ionization state in Pr123 system is constituted from two different configurations, and the energy of the f states in these two configurations has an important role in superconductivity properties of the system. Our calculations also show that in both Pr124 and Pr247 systems, suppression of superconductivity is weaker than that in the Pr123 system. This occurs due to the weaker Pr-O bond in both Pr124 and Pr247 systems. The role of the double chain and single chain on the conduction properties of these compounds has been investigated. We have also studied the effect of oxygen deficiency in Pr247 system, which seems to revive superconductivity in this system. Investigating the hole carriers in the CuO{sub 2} plane shows a correlation between superconductivity suppression and hole decrement in the planes. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Characterization and thermal behavior of PrMO{sub 3} (M = Co or Ni) ceramic materials obtained from gelatin

Energy Technology Data Exchange (ETDEWEB)

Aquino, F.M., E-mail: flavyma@hotmail.com [Federal University of Rio Grande of Norte, Laboratory of Catalysis and Refining – NUPRAR, Av. Senador Salgado Filho, 3000, CEP 59078-970, Natal-RN (Brazil); Melo, D.M.A. [Federal University of Rio Grande of Norte, Laboratory of Catalysis and Refining – NUPRAR, Av. Senador Salgado Filho, 3000, CEP 59078-970, Natal-RN (Brazil); Pimentel, P.M. [Universidade Federal Rural do Semi-Árido, Campus Angicos, CEP 59515-000, Angicos-RN (Brazil); Braga, R.M.; Melo, M.A.F.; Martinelli, A.E.; Costa, A.F. [Federal University of Rio Grande of Norte, Laboratory of Catalysis and Refining – NUPRAR, Av. Senador Salgado Filho, 3000, CEP 59078-970, Natal-RN (Brazil)

2012-09-15

Graphical abstract: The micrograph in figure shows sample calcined at temperature 900 °C. The sample exhibits morphology with considerable porosity and the formation of agglomerated nanometric particles. Gelatin provides the system with a large amount of organic matter, which is then removed during calcinations, favoring the appearance of pores in the material. Highlights: ► Oxides with PrNiO{sub 3} and PrCoO{sub 3} were prepared by new method synthesis. ► The gelatin, through its carboxylate groups and amine, is an efficient director. ► The obtained materials have magnetic properties and application in catalysis. ► The decomposition kinetic study of bonding groups of gelatin with metallic ions that takes part in the synthesis of PrMO{sub 3}. -- Abstract: Metal oxides with perovskite-type structure have attracted considerable interest in recent years due to their magnetic and electrical properties, as well as their catalytic activity. In this study, oxides with PrNiO{sub 3} and PrCoO{sub 3} composition were prepared by using gelatin powder as a precursor agent for its use as a catalyst. The powders obtained were calcined at 700 °C and 900 °C and characterized using the X-ray diffraction, thermal analysis (thermogravimetry and differential thermal analysis), infrared spectroscopy, temperature programed reduction and scanning electron microscopy techniques. Thermogravimetric data using the non-isothermal kinetic models of Flynn and Wall and “Model-free Kinetics” were used to determine the activation energy to study the decomposition kinetics of the ligand groups with system's metallic ions that takes part in the synthesis of PrMO{sub 3} (M = Ni or Co).

Cardiac cine MRI: Comparison of 1.5 T, non-enhanced 3.0 T and blood pool enhanced 3.0 T imaging

International Nuclear Information System (INIS)

Gerretsen, S.C.; Versluis, B.; Bekkers, S.C.A.M.; Leiner, T.

2008-01-01

Introduction: Cardiac cine imaging using balanced steady state free precession sequences (bSSFP) suffers from artefacts at 3.0 T. We compared bSSFP cardiac cine imaging at 1.5 T with gradient echo imaging at 3.0 T with and without a blood pool contrast agent. Materials and methods: Eleven patients referred for cardiac cine imaging underwent imaging at 1.5 T and 3.0 T. At 3.0 T images were acquired before and after administration of 0.03 mmol/kg gadofosveset. Blood pool signal-to-noise ratio (SNR), temporal variations in SNR, ejection fraction and myocardial mass were compared. Subjective image quality was scored on a four-point scale. Results: Blood pool SNR increased with more than 75% at 3.0 T compared to 1.5 T (p < 0.001); after contrast administration at 3.0 T SNR increased with 139% (p < 0.001). However, variations in blood pool SNR at 3.0 T were nearly three times as high versus those at 1.5 T in the absence of contrast medium (p < 0.001); after contrast administration this was reduced to approximately a factor 1.4 (p = 0.21). Saturation artefacts led to significant overestimation of ejection fraction in the absence of contrast administration (1.5 T: 44.7 ± 3.1 vs. 3.0 T: 50.7 ± 4.2 [p = 0.04] vs. 3.0 T post contrast: 43.4 ± 2.9 [p = 0.55]). Subjective image quality was highest for 1.5 T (2.8 ± 0.3), and lowest for non-enhanced 3.0 T (1.7 ± 0.6; p = 0.006). Conclusions: GRE cardiac cine imaging at 3.0 T after injection of the blood pool agent gadofosveset leads to improved objective and subjective cardiac cine image quality at 3.0 T and to the same conclusions regarding cardiac ejection fraction compared to bSSFP imaging at 1.5 T