Synthesis and characterization of heterobinuclear (La-Zn, Pr-Zn, Nd-Zn, Sm-Zn, Eu-Zn, Gd-Zn, Tb-Zn, Dy-Zn) azine-bridged complexes

International Nuclear Information System (INIS)

Singh, Bachcha; Srivastav, A.K.; Singh, P.K.

1997-01-01

Zinc(II) complex of 2-acetylpyridine salicyl aldazine (Haps) of the type Zn(aps) 2 (H 2 O) 2 has been synthesised. The reaction of Zn(aps) 2 (H 2 O) 2 with lanthanide chlorides, LnCl 3 (where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) yields azine-bridged heterobinuclear complexes of the formulae LnCl 3 Zn(aps) 2 (H 2 O) 2 . These complexes have been characterized by elemental analyses, molecular weight, conductance (solid and solution) and magnetic susceptibility measurements, mass, IR and electronic spectral data. X-ray powder diffraction data indicate the tetragonal unit lattice for Zn(aps) 2 (H 2 O) 2 and PrCl 3 Zn(aps) 2 (H 2 O) 2 . (author)

Synthesis and characterization of La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III) and Dy(III) complexes of 2-acetylfuran-2-thenoylhydrazone

International Nuclear Information System (INIS)

Singh, B.; Singh, Praveen K.

1998-01-01

The reaction of 2-acetylfuran-2-thenoylhydrazone(afth) with Ln(III) trichlorides yields complexes of the type [Ln(afth)Cl 2 (H 2 O)(EtOH)]Cl, [Ln(III) = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy]. The complexes have been characterized by molar conductance, magnetic susceptibility and TGA and DTA measurements, magnetic susceptibility and TGA and DTA measurements, FAB mass, infrared, proton NMR, electronic absorption and emission spectra. The terbium complex is found to be monomer from the FAB mass spectrum. The IR and NMR spectra suggest neutral tridentate behaviour of the Schiff base. A coordination number seven is proposed around the metal ions. Emission spectra suggest C 3v , symmetry around the metal ion with capped octahedron geometry for the europium complex. (author)

Synthesis and magnetism of μ-oxamido-bridged Cu2IILnIII - type heterotrinuclear complexes (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er)

International Nuclear Information System (INIS)

Li, Y.T.; Yan, C.W.

2001-01-01

Eight new Cu 2 II Ln III - type (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er) heterotrinuclear complexes bridged by N,N'-bis (2-aminopropyl)oxamidocopper(II) [Cu(oxdn)], namely Cu 2 (oxdn)Ln(NO 3 ) 3 , have been synthesized and characterized by elemental analyses, molar conductivity measurements and spectroscopic (IR, UV, ESR) studies. Magnetic susceptibility measurements (4.2 ∼300 K) and studies of Cu 2 (oxdn)Gd(NO 3 ) 3 complex have revealed that the central gadolinium(III) and terminal copper(II) ions are ferromagnetically coupled with the exchange integral J (Cu-Gd) = +2.98 cm -1 , while an antiferromagnetic coupling is detected between the terminal copper(II) metal ions with the exchange integral J' (Cu-Gd) = -0.75 cm -1 , on the basis of the spin Hamiltonian operator [H -2J(S Cu1 -S Gd +S Cu2 +S Gd )-2J'(S Cu1 S Cu2 )]. (author)

ions (RE = La, Pr, Nd, Sm, Gd and Dy)

Indian Academy of Sciences (India)

) zirconia), tendency of phase transformation (tetragonal to monoclinic () zirconia) and lattice strain were studied with mechanical property e.g. tensile strength of sol–gel derived ZrO2–2 mol% RE2O3 (RE = La, Pr, Nd, Sm, Gd and Dy) spun ...

Luminescence studies on Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses for WLED applications

Science.gov (United States)

Vijayakumar, M.; Uma, V.; Arunkumar, S.; Marimuthu, K.

2015-06-01

Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses have been prepared and optically characterized using absorption, luminescence and decay measurements. The Nephelauxetic ratios (β), Bonding parameters (δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were calculated to study the nature of the environment around the RE3+ ions in the prepared glasses. The yellow to blue (Y/B) intensity ratio and the chromaticity color coordinates were calculated from the luminescence measurements. The lifetimes of the 4F9/2 excited level were measured using decay curves and is found to decrease in the Dy3+:Eu3+ co-doped glass due to the occurrence of resonant energy transfer between Dy3+-Eu3+ ions and the non-exponential decay rates have been fitted with Inokuti-Hirayama (IH) model. The decay curves are well fitted for S= 6 suggesting that the interaction between active ions for the energy transfer is of dipole-dipole nature.

Photoluminescence and thermoluminescence characterization of Eu3+- and Dy3+ -activated Ca3(PO4)2 phosphor

International Nuclear Information System (INIS)

Nagpure, I.M.; Saha, Subhajit; Dhoble, S.J.

2009-01-01

Rare-earth-doped polycrystalline Ca 3 (PO 4 ) 2 :Eu, Ca 3 (PO 4 ) 2 :Dy and Ca 3 (PO 4 ) 2 :Eu,Dy phosphors prepared by a modified solid-state synthesis has been studied for its X-ray diffraction, thermoluminescence (TL) and photoluminescence (PL) characteristics. The PL emission spectra of the phosphor suggest the presence of Eu 3+ ion in Ca 3 (PO 4 ) 2 :Eu and Dy 3+ ion in Ca 3 (PO 4 ) 2 :Dy lattice sites. The TL glow curve of the Ca 3 (PO 4 ) 2 :Eu compounds has a simple structure with a prominent peak at 228 deg. C, while Ca 3 (PO 4 ) 2 :Dy peaking at 146 and 230 deg. C. TL sensitivity of phosphors are compared with CaSO 4 : Dy and found 1.52 and 1.20 times less in Ca 3 (PO 4 ) 2 :Eu and Ca 3 (PO 4 ) 2 :Dy phosphors, respectively. The Ca 3 (PO 4 ) 2 :Eu,Dy phosphors shows switching behavior under two different excitation wavelengths and enhancement in PL intensity of Dy 3+ ions were reported. The paper discusses the photoluminescence and thermoluminescence behavior of Eu 3+ and Dy 3+ ion in Ca 3 (PO 4 ) 2 hosts, it may be applicable to solid-state lighting as well as thermoluminescence dosimetry applications.

Eu-, Tb-, and Dy-Doped Oxyfluoride Silicate Glasses for LED Applications

DEFF Research Database (Denmark)

Zhu, C.F.; Wang, J.; Zhang, M.M.

2014-01-01

Luminescence glass is a potential candidate for the light-emitting diodes (LEDs) applications. Here, we study the structural and optical properties of the Eu-, Tb-, and Dy-doped oxyfluoride silicate glasses for LEDs by means of X-ray diffraction, photoluminescence spectra, Commission Internationale...... de L’Eclairage (CIE) chromaticity coordinates, and correlated color temperatures (CCTs). The results show that the white light emission can be achieved in Eu/Tb/Dy codoped oxyfluoride silicate glasses under excitation by near-ultraviolet light due to the simultaneous generation of blue, green, yellow......, and red-light wavelengths from Tb, Dy, and Eu ions. The optical performances can be tuned by varying the glass composition and excitation wavelength. Furthermore, we observed a remarkable emission spectral change for the Tb3+ single-doped oxyfluoride silicate glasses. The 5D3 emission of Tb3+ can...

Orange and reddish-orange light emitting phosphors: Sm{sup 3+} and Sm{sup 3+}/Eu{sup 3+} doped zinc phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Meza-Rocha, A.N., E-mail: ameza@fis.cinvestav.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México D.F., México (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Universita di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); IFAC CNR, Nello Carrara Institute of Applied Physics, MDF Lab, I-50019 Sesto Fiorentino, FI (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Universita di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Caldiño, U. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México D.F., México (Mexico)

2015-11-15

A spectroscopy study of Sm{sup 3+} and Sm{sup 3+}/Eu{sup 3+} doped zinc phosphate glasses is performed through photoluminescence spectra and decay time profile measurements. Under Sm{sup 3+} excitation at 344 nm, the Sm{sup 3+} singly doped glass shows an orange global emission with x=0.579 and y=0.414 CIE1931 chromaticity coordinates, whereas the Sm{sup 3+}/Eu{sup 3+} co-doped sample exhibits orange overall emissions (x=0.581 and y=0.398, and x=0.595 and y=0.387) and reddish-orange overall emission (x=0.634 and y=0.355) upon excitations at 344, 360 and 393 nm, respectively. Such luminescence from the co-doped sample is originated by the simultaneous emission of Sm{sup 3+} and Eu{sup 3+}. Under Sm{sup 3+} excitation at 344 and 360 nm, the Eu{sup 3+} emission is sensitized and enhanced by Sm{sup 3+} through a non-radiative energy transfer process. The non-radiative nature was inferred from the shortening of the Sm{sup 3+} lifetime observed in the Sm{sup 3+}/Eu{sup 3+} co-doped sample. An analysis of the Sm{sup 3+} emission decay time profiles using the Inokuti–Hirayama model suggests that an electric quadrupole–quadrupole interaction into Sm–Eu clusters might dominate the energy transfer process, with an efficiency of 0.17. - Highlights: • Zinc phosphate glasses are optically activated with Sm{sup 3+}/Eu{sup 3+} (ZPOSmEu). • Non-radiative energy transfer Sm{sup 3+}→Eu{sup 3+} takes place in ZPOSmEu. • ZPOSmEu overall emission can be modulated with the excitation wavelength. • ZPOSmEu might be useful as orange/reddish-orange phosphor for UV-white LEDs.

Energy transfer and colorimetric properties of Eu3+/Dy3+ co-doped Gd2(MoO4)3 phosphors

International Nuclear Information System (INIS)

Wan Jing; Cheng Lihong; Sun Jiashi; Zhong Haiyang; Li Xiangping; Lu Weili; Tian Yue; Lin Hai; Chen Baojiu

2010-01-01

Dy 3+ single-doped and Eu 3+ /Dy 3+ co-doped gadolinium molybdate (Gd 2 (MoO 4 ) 3 ) phosphors were synthesized by a traditional solid-state reaction method. The XRD was used to confirm the crystal structure of the phosphors. The energy transfer between Eu 3+ and Dy 3+ was observed and studied. The Eu 3+ concentration can hardly affect the blue and yellow emission intensities of Dy 3+ , and the Eu 3+ emission intensity increases with the increase of Eu 3+ concentration. Co-doping with Eu 3+ compensated the red emission component of the Dy 3+ doped Gd 2 (MoO 4 ) 3 phosphor. Introducing proper amount of Eu 3+ can improve the colorimetric performance of the phosphors.

Absorption and emission analysis of RE3+(Sm3+ and Dy3+): lithium boro tellurite glasses.

Science.gov (United States)

Sooraj Hussain, N; Hungerford, G; El-Mallawany, R; Gomes, M J M; Lopes, M A; Ali, Nasar; Santos, J D; Buddhudu, S

2009-06-01

This paper reports on the development and spectral analysis of Sm3+ (1.0%) and Dy3+ (1.0%) doped lithium-boro-tellurite glasses. A bright orange (4G5/2-->6H7/2) along with a red (4G5/2-->6H9/2) and a yellow (4G5/2-->6H5/2) emission transition have been measured from Sm3+ doped lithium-boro-tellurite glass. Both blue (4F9/2-->6H15/2) and yellow (4F9/2-->6H13/2) emission bands have been obtained from Dy3+ glass. From the measured decay profiles, the lifetimes of the emissions of the Sm3+ glass (4G5/2-->6H5/2, 7/2, 9/2 and 11/2) at an excitation of 401 nm have been found to be in the range 0.47-0.81 ms, and with respect to the Dy3+ emissions (4F9/2-->6H15/2 and 13/2), with excitation at 450 nm, are measured to be in the range of 0.302-0.307 ms. Stimulated emission cross-sections (sigmapE) of the measured emission transitions have also been computed and the values are in the range of (0.38-1.20) x 10(-20) cm2 for Sm3+ and for Dy3+ doped lithium-boro-tellurite glass the values are (0.66-1.39) x 10(-20) cm2.

Crystal structure of RCoIn5 (R - Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Y) and R2CoIn8 (R - Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Y) compounds

International Nuclear Information System (INIS)

Kalychak, Ya.M.; Zaremba, V.I.; Baranyak, V.M.; Bruskov, V.A.; Zavalij, P.Yu.

1989-01-01

Usng X-ray diffraction method of monocrystal, crystal structure of HoCoIn 5 compound belonging to the HoCoGa 5 structural type is determined. Using the method of powder belonging of CeCoIn 5 structure to the HoCoGa 5 structural type is confirmed. Isostructural compounds with Y, Pr, Nd, Sm, Gd, Tb, Dy are detected. Their lattice periods are determined. Using the method of powder belonging of Ce 2 CoIn 8 compound structure to Ho 2 CoGa 8 structural type is determined. Isostructural compounds with Y, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm are detected and their lattice periods are determined

Long lasting yellow phosphorescence and photostimulated luminescence in Sr3SiO5 : Eu2+ and Sr3SiO5 : Eu2+, Dy3+ phosphors

International Nuclear Information System (INIS)

Sun Xiaoyuan; Zhang Jiahua; Zhang Xia; Luo Yongshi; Wang Xiaojun

2008-01-01

We report the observation of long lasting yellow phosphorescence and photostimulated luminescence (PSL) in Sr 3 SiO 5 : Eu 2+ and Sr 3 SiO 5 : Eu 2+ , Dy 3+ phosphors. The decay patterns of phosphorescence and thermoluminescence curves demonstrate that introduction of Dy 3+ into Sr 3 SiO 5 : Eu 2+ can generate a large number of shallow traps and deep traps. The generated deep traps prolong the phosphorescence up to 6 h after UV irradiation. The PSL is studied under 808 nm excitation. Slow rising and falling edges of the emission in Sr 3 SiO 5 : Eu 2+ , Dy 3+ are observed, showing a retrapping process by the generated shallow traps due to co-doping Dy 3+ .

Photoluminescence and thermoluminescence properties of Eu2+ doped and Eu2+ ,Dy3+ co-doped Ba2 MgSi2 O7 phosphors.

Science.gov (United States)

Sao, Sanjay Kumar; Brahme, Nameeta; Bisen, D P; Tiwari, Geetanjali

2016-11-01

In this work, we report the preparation, characterization, comparison and luminescence mechanisms of Eu 2 + -doped and Eu 2 + ,Dy 3 + -co-doped Ba 2 MgSi 2 O 7 (BMSO) phosphors. Prepared phosphors were synthesized via a high temperature solid-state reaction method. All prepared phosphors appeared white. The phase structure, particle size, and elemental analysis were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) analysis. The luminescence properties of the phosphors were investigated by thermoluminescence (TL) and photoluminescence (PL). The PL excitation and emission spectra of Ba 2 MgSi 2 O 7 :Eu 2 + showed the peak to be around 381 nm and 490 nm respectively. The PL excitation spectrum of Ba 2 MgSi 2 O 7 :Eu 2 + Dy 3 + showed the peak to be around 341 nm and 388 nm, and the emission spectrum had a broad band around 488 nm. These emissions originated from the 4f 6 5d 1 to 4f 7 transition of Eu 2 + . TL analysis revealed that the maximum TL intensity was found at 5 mol% of Eu 2 + doping in Ba 2 MgSi 2 O 7 phosphors after 15 min of ultraviolet (UV) light exposure. TL intensity was increased when Dy 3 + ions were co-doped in Ba 2 MgSi 2 O 7 :Eu 2 + and maximum TL intensity was observed for 2 mol% of Dy 3 + . TL emission spectra of Ba 1.95 MgSi 2 O 7 :0.05Eu 2 + and Ba 1.93 MgSi 2 O 7 :0.05Eu 2 + ,0.02Dy 3 + phosphors were found at 500 nm. TL intensity increased with UV exposure time up to 15 min, then decreased for the higher UV radiation dose for both Eu doping and Eu,Dy co-doping. The trap depths were calculated to be 0.54 eV for Ba 1.95 MgSi 2 O 7 :0.05Eu 2 + and 0.54 eV and 0.75 eV for Ba 1.93 MgSi 2 O 7 :0.05Eu 2 + ,0.02Dy 3 + phosphors. It was observed that co-doping with small amounts of Dy 3 + enhanced the thermoluminescence properties of Ba 2 MgSi 2 O 7 phosphor. Copyright © 2016 John Wiley & Sons, Ltd. [Correction added on 5 April 2016, after first online publication: The

Tunable photoluminescence and magnetic properties of Dy(3+) and Eu(3+) doped GdVO4 multifunctional phosphors.

Science.gov (United States)

Liu, Yanxia; Liu, Guixia; Dong, Xiangting; Wang, Jinxian; Yu, Wensheng

2015-10-28

A series of Dy(3+) or/and Eu(3+) doped GdVO4 phosphors were successfully prepared by a simple hydrothermal method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometry (EDS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the as-prepared samples are pure tetragonal phase GdVO4, taking on nanoparticles with an average size of 45 nm. Under ultraviolet (UV) light excitation, the individual Dy(3+) or Eu(3+) ion activated GdVO4 phosphors exhibit excellent emission properties in their respective regions. The mechanism of energy transfer from the VO4(3-) group and the charge transfer band (CTB) to Dy(3+) and Eu(3+) ions is proposed. Color-tunable emissions in GdVO4:Dy(3+),Eu(3+) phosphors are realized through adopting different excitation wavelengths or adjusting the appropriate concentration of Dy(3+) and Eu(3+) when excited by a single excitation wavelength. In addition, the as-prepared samples show paramagnetic properties at room temperature. This kind of multifunctional color-tunable phosphor has great potential applications in the fields of photoelectronic devices and biomedical sciences.

Luminescence and energy transfer of Sm3+ and Eu3+ in Ca2PO4Cl

International Nuclear Information System (INIS)

Wang, Zhijun; Li, Panlai; Yang, Zhiping; Guo, Qinglin

2014-01-01

Sm 3+ , Eu 3+ , and Sm 3+ –Eu 3+ doped Ca 2 PO 4 Cl phosphors are synthesized by a solid-state method. Ca 2 PO 4 Cl:Sm 3+ can produce red emission under the 400 nm radiation excitation, and the emission peak is located at 601 nm, which is assigned to the 4 G 5/2 → 6 H 7/2 transition of Sm 3+ . Ca 2 PO 4 Cl:Eu 3+ can create red emission under the 392 nm radiation excitation, and the strongest peak is located at 620 nm, which is attributed to the 5 D 0 → 7 F 2 transition of Eu 3+ . The energy transfer from Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl has been validated and the critical distance (R c ) of Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl is calculated to be 1.14 nm. With increasing Eu 3+ doping concentration, the energy transfer efficiency (Sm 3+ →Eu 3+ ) gradually increases to 53.7%. The luminescence property of Ca 2 PO 4 Cl:Sm 3+ , Eu 3+ can be tuned by properly tuning the relative ratio of Sm 3+ –Eu 3+ , and the emission intensity of Ca 2 PO 4 Cl:Eu 3+ can be greatly enhanced by codoped Sm 3+ . - Highlights: • Ca 2 PO 4 Cl:Sm 3+ , Eu 3+ can produce red emission under the 400 nm radiation excitation. • The energy transfer from Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl has been validated. • The critical distance of Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl is calculated to be 1.14 nm

Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al₂O₄:Eu2+, Dy3+ Phosphors.

Science.gov (United States)

Xie, Qidi; Li, Bowen; He, Xin; Zhang, Mei; Chen, Yan; Zeng, Qingguang

2017-10-18

(Sr, Ca, Ba)Al₂O₄:Eu 2+ , Dy 3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al₂O₄:Eu 2+ ,Dy 3+ phosphors, the different phase formation from monoclinic SrAl₂O₄ phase to hexagonal SrAl₂O₄ phase to monoclinic CaAl₂O₄ phase was observed when the Ca content increased. The emission color of SrAl₂O₄:Eu 2+ , Dy 3+ phosphors varied from green to blue. For the (Sr, Ba)Al₂O₄:Eu 2+ , Dy 3+ phosphors, different phase formation from the monoclinic SrAl₂O₄ phase to the hexagonal BaAl₂O₄ phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl₂O₄:Eu 2+ , Dy 3+ changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr 2+ with Ba 2+ cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED). Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(In)N near UV chips.

Calculations of the Low-Lying Structures in the Even-Even Nd/Sm/Gd/Dy Isotopes

Science.gov (United States)

Lee, Su Youn; Lee, J. H.; Lee, Young Jun

2018-05-01

The nuclear structure of deformed nuclei has been studied using the interacting boson model (IBM). In this study, energy levels and E2 transition probabilities were determined for even nuclei in the Nd/Sm/Gd/Dy chains which have a transition characteristic between the rotational, SU(3) and vibrational, U(5) limits. The structure of the nuclei exhibits a slight breaking of the SU(3) symmetry in the direction of U(5), and therefore, we add the d-boson number operator n d , which is the main term of the U(5) symmetric Hamiltonian, to the SU(3) Hamiltonian of the IBM. The calculated results for low-lying energy levels and E2 transition rates in Nd/Sm/Gd/Dy isotopes are in reasonably good agreement with known experimental results.

Tailored white light emission in Eu3+/Dy3+ doped tellurite glass phosphors containing Al3+ ions

Science.gov (United States)

Walas, Michalina; Piotrowski, Patryk; Lewandowski, Tomasz; Synak, Anna; Łapiński, Marcin; Sadowski, Wojciech; Kościelska, Barbara

2018-05-01

Tellurite glass systems modified by addition of aluminum fluoride AlF3 have been successfully synthesized as host matrices for optically active rare earth ions RE3+ (RE3+ = Eu3+, Dy3+). Samples with different Eu3+ to Dy3+ molar ratio have been studied in order to determine possibility of white light emission via UV excitation. Structural investigations confirmed amorphous character of materials whereas spectroscopic studies brought more insight into glass network's nature. FTIR results shown presence of two features related to tellurite glass matrix (in 490-935 cm-1 spectral region) and another one (940-1250 cm-1) due to aluminum addition. Especially, Al-O and Te-O-Al bonds of AlO4 tetrahedrons have been found. AlO4 units are considered as glass formers that improve network's strength and thermal resistivity against devitrification. Based on XPS studies of Al3+ photoelectron band the existence of Al-O and also Al-F bonds have been examined. Moreover, signals originating from Eu3+ and Dy3+ have been found confirming their valence state. Luminescence results revealed possibility of simultaneous UV excitation of Eu3+ and Dy3+ ions. Excitation with λexc = 390 and 393 nm resulted in white light generation starting from warm white to neutral and cool white depending on Eu3+ concentration and used excitation wavelength. Additionally, increase of decay lifetime of Eu3+ induced by Al3+ presence have been revealed based on luminescence decay analysis. Thus, tellurite glass systems modified by AlF3 and doped with Eu3+/Dy3+ may be considered as promising candidates for white light emitting sources.

Analysis of energy transfer based emission spectra of (Sm{sup 3+}, Dy{sup 3+}): Li{sub 2}O–LiF–B{sub 2}O{sub 3}–CdO glasses

Energy Technology Data Exchange (ETDEWEB)

Naresh, V., E-mail: varna.naresh@gmail.com; Buddhudu, S., E-mail: profsb_svuniv@hotmail.com

2014-03-15

The present paper brings out the results concerning the preparation and optical properties of Sm{sup 3+} and Dy{sup 3+} each ion separately in four different concentrations (0.1, 0.5, 1.0 and 1.5 mol%) and also together doped (1 mol% Dy{sup 3+}+x mol% Sm{sup 3+}): Li{sub 2}O–LiF–B{sub 2}O{sub 3}–CdO (where x=0.1, 0.5, 1.0 and 1.5 mol%) glasses by a melt quenching method. Sm{sup 3+} doped base glasses have displayed an intense orange emission at 602 nm ({sup 4}G{sub 5/2}→{sup 6}H{sub 7/2}) with an excitation at 403 nm and Dy{sup 3+} doped glasses have shown two emissions located at 486 nm ({sup 4}F{sub 9/2}→{sup 6}H{sub 15/2}; blue) and 577 nm ({sup 4}F{sub 9/2}→{sup 6}H{sub 13/2}; yellow) with λ{sub exci}=387 nm. The co-doped (Dy{sup 3+}+Sm{sup 3+}) lithium fluoro-boro cadmium glasses have been excited with an excitation at 387 nm of Dy{sup 3+} which has resulted in with a significant reduction in Dy{sup 3+} emission, at the same time there exists an increase in the reddish-orange emission of Sm{sup 3+} due to an energy transfer from Dy{sup 3+} to Sm{sup 3+}. The non-radiative energy transfer from Dy{sup 3+} to Sm{sup 3+} is governed by dipole–quadrupole interactions as is explained in terms of their emission spectra, donor lifetime, energy level diagram and energy transfer characteristic factors. -- Highlights: • In co-doped (Dy{sup 3+}+Sm{sup 3+}): LFBCd glass, reddish-orange emission due to Sm{sup 3+} ({sup 4}F{sub 9/2}→{sup 6}H{sub J}) has been enhanced due to an energy transfer from Dy{sup 3+} ions in the glass. • This has been evidenced from a lowering trend in the emission transition lifetimes of donor (Dy{sup 3+}) ions with increasing acceptor (Sm{sup 3+}) concentration. • Energy transfer mechanism involved in Dy{sup 3+}→Sm{sup 3+} has been explained in terms of I–H luminescence decay curve analysis.

Photoluminescence characteristics of reddish-orange Eu{sup 3+} or Sm{sup 3+} singly-doped and Eu{sup 3+} and Sm{sup 3+} co-doped KZnGd(PO{sub 4}){sub 2} phosphors

Energy Technology Data Exchange (ETDEWEB)

Jeong, Jun Ho; Bandi, Vengala Rao; Grandhe, Bhaskar Kumar; Jang, Ki Wan; Lee, Ho Sueb [Changwon National University, Changwon (Korea, Republic of); Yi, Soung Soo [Silla University, Busan (Korea, Republic of); Jeong, Jung Hyun [Pukyong National University, Busan (Korea, Republic of)

2011-02-15

Eu{sup 3+} or Sm{sup 3+} singly-doped and Eu{sup 3+} and Sm{sup 3+} co-doped KZnGd(PO{sub 4}){sub 2} phosphors were synthesized by using a conventional solid state reaction method at 750 .deg. C. The emission spectra of KZnGd{sub 1-x}(PO{sub 4}){sub 2}:Eu{sup 3+}{sub x} with {lambda}{sub ex} = 395 nm and KZnGd{sub 1-y}(PO{sub 4}){sub 2}:Sm{sup 3+}{sub y} with {lambda}{sub ex} = 403 nm phosphors showed intense {sup 5}D{sub 0} {yields} {sup 7}F{sub 1}, {sup 4}G{sub 5/2} {yields} {sup 6}H{sub 7/2} emission transitions at 595 nm and 599 nm, respectively. The optimum relative intensity of the KZnGd{sub 1-x-y}(PO{sub 4}){sub 2}:Eu{sup 3+}{sub x} , Sm{sup 3+}{sub y} phosphor was obtained for the doping concentrations of (x = 0.09, y = 0.01). In addition, the temperature dependent luminescence intensity of the synthesized phosphors was investigated and the thermal stability of the KZnGd(PO{sub 4}){sub 2}:Eu{sup 3+} phosphor was found to be higher than that of standard YAG:Ce{sup 3+} and KZnGd{sub 1-x-y}(PO{sub 4}){sub 2}:Eu{sup 3+}{sub x} Sm{sup 3+}{sub y} under near ultra-violet (NUV) light emitting diode excitation (LED). Therefore, we suggest that Eu{sup 3+} or Sm{sup 3+} singly-doped and Eu{sup 3+} and Sm{sup 3+} co-doped KZnGd(PO{sub 4}){sub 2} phosphors should be efficient for different red-color-emitting display device applications and NUV-LED-based white-light-emitting diodes.

Re-dispersion and film formation of GdVO4 :  Ln3+ (Ln3+ = Dy3+, Eu3+, Sm3+, Tm3+) nanoparticles: particle size and luminescence studies.

Science.gov (United States)

Shanta Singh, N; Ningthoujam, R S; Phaomei, Ganngam; Singh, S Dorendrajit; Vinu, A; Vatsa, R K

2012-04-21

GdVO(4) : Ln(3+) (Ln(3+) = Dy(3+), Eu(3+), Sm(3+), Tm(3+)) nanoparticles are prepared by a simple chemical route at 140 °C. The crystallite size can be tuned by varying the pH of the reaction medium. Interestingly, the crystallite size is found to increase significantly when pH increases from 6 to 12. This is related to slower nucleation of the GdVO(4) formation with increase of VO(4)(3-) present in solution. The luminescence study shows an efficient energy transfer from vanadate absorption of GdVO(4) to Ln(3+) and thereby enhanced emissions are obtained. A possible reaction mechanism at different pH values is suggested in this study. As-prepared samples are well dispersed in ethanol, methanol and water, and can be incorporated into polymer films. Luminescence and its decay lifetime studies confirm the decrease in non-radiative transition probability with the increase of heat treatment temperature. Re-dispersed particles will be useful in potential applications of life science and the film will be useful in display devices.

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy(3+),Tb(3+),Eu(3+) phosphors.

Science.gov (United States)

Guan, Hongxia; Sheng, Ye; Xu, Chengyi; Dai, Yunzhi; Xie, Xiaoming; Zou, Haifeng

2016-07-20

A series of Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped GdF3 phosphors were synthesized by a glutamic acid assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure GdF3. The obtained samples have a peanut-like morphology with a diameter of about 270 nm and a length of about 600 nm. Under UV excitation, GdF3:Dy(3+), GdF3:Tb(3+) and GdF3:Eu(3+) samples exhibit strong blue, green and red emissions, respectively. By adjusting their relative doping concentrations in the GdF3 host, the different color hues of green and red light are obtained by co-doped Dy(3+), Tb(3+) and Tb(3+), Eu(3+) ions in the GdF3 host, respectively. Besides, there exist two energy transfer pairs in the GdF3 host: (1) Dy(3+) → Tb(3+) and (2) Tb(3+) → Eu(3+). More significantly, in the Dy(3+), Tb(3+), and Eu(3+) tri-doped GdF3 phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of Eu(3+). In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K) and low temperature (2 K). It is obvious that multifunctional Dy(3+), Tb(3+), Eu(3+) tri-doped GdF3 materials including tunable multicolors and intrinsic paramagnetic properties may have potential applications in the field of full-color displays.

Sm isotope composition and Sm/Eu ratio determination in an irradiated 153Eu sample by ion exchange chromatography-quadrupole inductively coupled plasma mass spectrometry combined with double spike isotope dilution technique

International Nuclear Information System (INIS)

Bourgeois, M.; Isnard, H.; Gourgiotis, A.; Stadelmann, G.; Gautier, C.; Mialle, S.; Nonell, A.; Chartier, F.

2011-01-01

Within the framework of the research undertaken by the French Atomic Energy Commission on transmutation of long-lived radionuclides, targets of highly enriched actinides and fission products were irradiated in the fast neutron reactor Phenix. Precise and accurate measurements of the isotopic and elemental composition of the enriched elements are therefore required. In order to obtain the uncertainties of several per mil and to reduce handling time and exposure to analyst on radioactive material, the on-line coupling of ion exchange chromatography with quadrupole inductively coupled plasma mass spectrometry has been associated with the technique of the double spike isotope dilution. We present in this paper the results obtained on an irradiated sample of Europium oxide powder (enriched at 99.13% in 153 Eu). After irradiation of around 5 mg of Eu 2 O 3 powder the theoretical calculations predict the formation of several micrograms of gadolinium and samarium isotopes. In relation to the very high activity of the sample after irradiation and the very low quantity of Sm formed, the on-line ion exchange chromatography separation of Gd, Sm and Eu before Sm isotope ratio measurements has been developed for the quantification of the 152 Sm/ 153 Eu ratio. These on-line measurements were associated with the double spike isotope dilution technique after calibration of a 147 Sm/ 151 Eu spike solution. The external reproducibility of Sm isotopic ratios was determined to be around 0.5% (2 σ) resulting in a final uncertainty on the 152 Sm/ 153 Eu ratio of around 1% (2 σ). These on-line measurements present therefore a robust and high-throughput alternative to the thermal-ionisation mass spectrometry technique used so far in combination with off-line chromatographic separation, particularly in nuclear applications where characterisation of high activity sample solutions is required. (authors)

Effect of concentration on the photoluminescence properties of Sm3+ and Dy3+: cadmium lithium boro tellurite glasses.

Science.gov (United States)

Raju, K Vemasevana; Sailaja, S; Reddy, M Bhushana; Giridhar, P; Raju, C Nageswara; Reddy, B Sudhakar

2012-02-01

Rare-earth (Sm3+ or Dy3+) ions doped cadmium lithium boro tellurite glasses have been prepared by melt quenching method for their spectral studies. From X-ray diffraction (XRD) patterns the glass amorphous nature has been confirmed. Vis-NIR absorption, excitation and emission spectra of these glasses have been analyzed systematically and also rare earth ion concentration is optimised Sm3+: CLiBT glasses have shown strong orange-reddish emission at 598 nm (4G5/2-->6H7/2) with an excitation wavelength lambda(exci) = 401 nm and Dy3+: CLiBT glasses have shown strong yellow emission at 574 nm (6F9/2-->6H13/2) with lambda(exci) = 451 nm.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-05-15

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

Combustion synthesis of Eu 2+ and Dy 3+ activated Sr 3 (VO 4 ) 2 ...

Indian Academy of Sciences (India)

2:Eu,Dy phosphors are presented in this paper. PL emission of Sr3(VO4)2:Eu phosphor shows green broad emission band centring at 511 nm and a red sharp band at 614 nm by excitation wavelength of 342 nm. The PL emission spectrum of ...

Fabrication and Luminescent properties of ZnWO{sub 4}:Eu{sup 3+}, Dy{sup 3+} white light-emitting phosphors

Energy Technology Data Exchange (ETDEWEB)

Zhai, Yongqing, E-mail: zhaiyongqinghbu@163.com; Wang, Meng; Zhao, Qian; Yu, Jiabao; Li, Xuemin

2016-04-15

ZnWO{sub 4}:Eu{sup 3+},Dy{sup 3+} white light-emitting phosphors were prepared by a hydrothermal method followed with calcination process. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectrum, Raman spectra, scanning electron microscope (SEM), transmission electron microscope (TEM), diffused reflectance spectra, photoluminescence excitation and emission spectra, and photoluminescence decay curves. Furthermore, external quantum efficiency of ZnWO{sub 4}:Eu{sup 3+},Dy{sup 3+} was determined. The results showed that the obtained phosphors have monoclinic wolframite structure. The particles of the phosphors was nearly spherical in shape, and the particle size was about 70–100 nm. Upon excitation at UV light, the white light-emitting can be obtained by combining the blue–green emission of tungstate group and characteristic emission of Eu{sup 3+} and Dy{sup 3+}. Based on the excitation/emission spectra and decay curves, the energy transfer and photoluminescence mechanism for ZnWO{sub 4}:Eu{sup 3+}, Dy{sup 3+} system were discussed.

Investigation of thermoluminescence and electron-vibrational interaction parameters in SrAl2O4:Eu2+, Dy3+ phosphors

International Nuclear Information System (INIS)

Pardhi, Shilpa A.; Nair, Govind B.; Sharma, Ravi; Dhoble, S.J.

2017-01-01

Combustion synthesis method was employed for the synthesis of green-emitting monoclinic SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors. The phase-purity of the prepared phosphors were examined using X-ray diffraction (XRD). The prepared phosphors exhibited green light emission with the peak centred at 510 nm, under 350 nm UV excitation. The excitation and emission spectra were analysed and the parameters of electron-vibrational interaction (EVI), such as the Huang–Rhys factor, effective phonon energy and zero-phonon line position were estimated using the spectrum fitting method. Thermoluminescence (TL) behaviour of the as-prepared phosphors were analysed for UV and 137 Cs γ-ray source irradiation. TL glow curves for UV-irradiated SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors were analysed. - Highlights: • Photoluminescence and thermoluminescence properties of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors were analysed. • Electron-vibrational interaction (EVI) parameters of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors were determined. • The phosphors are found to exhibit green light emission.

Luminescence behaviors of Eu- and Dy-codoped alkaline earth metal aluminate phosphors through potassium carbonate coprecipitation

Energy Technology Data Exchange (ETDEWEB)

Liang, Chen-Jui, E-mail: cjliang@fcu.edu.tw; Siao, Hao-Yi

2016-07-01

An electronic energy mechanism of activator and sensitizer was established to describe the luminescence behaviors of Eu- and Dy-codoped M(II)Al{sub 2}O{sub 4} (M(II) = Ba, Sr, Ca, Mg) phosphors through potassium carbonate coprecipitation. Experimental results demonstrated that the prepared phosphors exhibited superior crystallinity at a temperature lower than 950 °C. The phosphors are ordered according to emission intensity as follows Ca- > Ba- > Sr- > Mg-containing phosphors. The energy level for Eu{sup 2+} 4f{sup 6}5d{sup 1} → 4f{sup 7}, Eu{sup 3+4}D{sub 0} → {sup 7}F, and Dy{sup 3+4}F{sub 9/2} → {sup 6}H transitions and the effects of nephelauxetic and crystal field in Ba-, Sr-, and Ca-containing phosphors were discussed. The energy gap, (hv){sub em}, between 5d and 4f of Eu{sup 2+} ion is strongly affected by host composition, crystal field strength, and nephelauxetic effect. The infrared emission of 4f{sub 9/2} → 6h for Dy{sup 3+} is merely depend on the transfer of energy from Eu{sup 2+} upon excited. Ca-containing phosphor with maximum (hv){sub em} is attributed to the lowest bond length of Ca−O and highest ionization potential of Ca{sup 2+} ion, which leads to the effects of crystal field and nephelauxetic greater than that in the other phosphors. - Highlights: • The list of the collected figure captions: • Develop a new coprecipitation method to prepare high efficiency phosphors. • Obtain superior crystallinity with lower calcination temperature. • Luminescence behavior of Eu- and Dy-codoped on aluminate phosphors is discussed. • Investigate the effects of alkaline earth metal containing on crystal field and nephelauxetic.

Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ Phosphors

OpenAIRE

Qidi Xie; Bowen Li; Xin He; Mei Zhang; Yan Chen; Qingguang Zeng

2017-01-01

(Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al2O4:Eu2+, Dy3+ phosphors, the different phase formation from monoclinic SrAl2O4 phase to hexagonal SrAl2O4 phase to monoclinic CaAl2O4 phase was observed when the Ca content increased. The emission color of SrAl2O4:Eu2+, Dy3+ phosphors varied from green to ...

Emission analysis of RE3+ (RE = Sm, Dy):B2O3-TeO2-Li2O-AlF3 glasses.

Science.gov (United States)

Raju, C Nageswara; Sailaja, S; Kumari, S Pavan; Dhoble, S J; Kumar, V Ramesh; Ramanaiah, M V; Reddy, B Sudhakar

2013-01-01

This article reports on the optical properties of 0.5% mol of Sm(3+), Dy(3+) ion-doped B2O3-TeO2-Li2O-AlF3 (LiAlFBT) glasses. The glass samples were characterized by optical absorption and emission spectra. Judd-Ofelt theory was applied to analyze the optical absorption spectra and calculate the intensity parameters and radiative properties of the emission transitions. The emission spectra of Sm(3+) and Dy(3+):LiAlFBT glasses showed a bright reddish-orange emission at 598 nm ((4)G5/2 → (6)H7/2) and an intense yellow emission at 574 nm ((4)F9/2 → (6)H13/2), respectively. Full width at half maximum (FWHM), stimulated emission cross section, gain bandwidth and optical gain values were also calculated to extend the applications of the Sm(3+) and Dy(3+):LiAlFBT glasses. Copyright © 2012 John Wiley & Sons, Ltd.

Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ Phosphors

Science.gov (United States)

Xie, Qidi; Li, Bowen; He, Xin; Zhang, Mei; Chen, Yan; Zeng, Qingguang

2017-01-01

(Sr, Ca, Ba)Al2O4:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al2O4:Eu2+, Dy3+ phosphors, the different phase formation from monoclinic SrAl2O4 phase to hexagonal SrAl2O4 phase to monoclinic CaAl2O4 phase was observed when the Ca content increased. The emission color of SrAl2O4:Eu2+, Dy3+ phosphors varied from green to blue. For the (Sr, Ba)Al2O4:Eu2+, Dy3+ phosphors, different phase formation from the monoclinic SrAl2O4 phase to the hexagonal BaAl2O4 phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl2O4:Eu2+, Dy3+ changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr2+ with Ba2+ cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED). Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(In)N near UV chips. PMID:29057839

Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, BaAl2O4:Eu2+, Dy3+ Phosphors

Directory of Open Access Journals (Sweden)

Qidi Xie

2017-10-01

Full Text Available (Sr, Ca, BaAl2O4:Eu2+, Dy3+ phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, CaAl2O4:Eu2+,Dy3+ phosphors, the different phase formation from monoclinic SrAl2O4 phase to hexagonal SrAl2O4 phase to monoclinic CaAl2O4 phase was observed when the Ca content increased. The emission color of SrAl2O4:Eu2+, Dy3+ phosphors varied from green to blue. For the (Sr, BaAl2O4:Eu2+, Dy3+ phosphors, different phase formation from the monoclinic SrAl2O4 phase to the hexagonal BaAl2O4 phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl2O4:Eu2+, Dy3+changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr2+ with Ba2+ cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED. Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(InN near UV chips.

YVO{sub 4}:Eu{sup 3+}, Dy{sup 3+}-Fe{sub 3}O{sub 4} co-doped nanocomposites: preparation, luminescent, and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Liu Deming; Shi Jianhui; Tong Lizhu; Ren Xiaozhen; Li Quanhong; Yang Hua, E-mail: huayang86@sina.com [Jilin University, College of Chemistry (China)

2012-11-15

A series of different concentrations of Eu{sup 3+} and Dy{sup 3+} ions co-doping yttrium vanadate phosphors coated with Fe{sub 3}O{sub 4} (YVO{sub 4}:Eu{sup 3+}, Dy{sup 3+}-Fe{sub 3}O{sub 4}) was successful prepared by using two steps route including sol-gel method and hydrothermal method. The resulting phase formation, particle morphology, structure, luminescent, and magnetic properties were examined by X-ray diffraction, transmission electron microscopy, photoluminescence spectra, and vibrating sample magnetometer. The results indicate that the diameter of the YVO{sub 4}:Eu{sup 3+}, Dy{sup 3+}-Fe{sub 3}O{sub 4} nanocomposites is 100-300 nm. The special saturation magnetization Ms of the nanocomposites is 53 emu/g. Additionally, the emission intensities of YVO{sub 4}:Eu{sup 3+} or Dy{sup 3+} ions are regularly changed with the emission doping concentrations. After coating with Fe{sub 3}O{sub 4}, the variation of the luminescent intensity of YVO{sub 4}:Eu{sup 3+}, Dy{sup 3+}-Fe{sub 3}O{sub 4} magnetic phosphors is different.

1,3-thiazole as suitable antenna ligand for lanthanide photoluminescence in [LnCl{sub 3}(thz){sub 4}].0.5thz, Ln = Sm, Eu, Gd, Tb, Dy

Energy Technology Data Exchange (ETDEWEB)

Dannenbauer, Nicole; Mueller-Buschbaum, Klaus [Wuerzburg Univ. (Germany). Inst. for Inorganic Chemistry; Kuzmanoski, Ana; Feldmann, Claus [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Inorganic Chemistry

2014-02-15

The series of luminescent monomeric lanthanide thiazole complexes [LnCl{sub 3}(thz){sub 4}].0.5thz (Ln = Sm, Eu, Gd, Tb, Dy; thz = 1,3-thiazole) has been synthesised and characterised by powder and single-crystal X-ray diffraction, IR and photoluminescence spectroscopy, DTA/TG as well as elemental analysis. The colourless compounds exhibit photoluminescence in the visible region with varying quantum efficiencies up to QY = 48 % for [LnCl{sub 3}(thz){sub 4}].0.5thz. Both, the lanthanide ions as well as the thiazole ligand contribute to the luminescence. Excitation can be achieved via intra-4f transitions and by exciting the ligand, emission is observed mainly from the lanthanide ions again by 4f transitions. Thiazole can transfer energy to the lanthanide ions, which further feeds the lanthanide emission by an efficient antenna effect even at room temperature. The lanthanide ions show pentagonal-bipyramidal coordination by three chloride anions and four N atoms of 1,3-thiazole, which leads to a strong {sup 5}D{sub 0} → {sup 7}F{sub 4} transition for europium. Significant differences arise as compared to thiophene complexes because no sulphur atom is involved in the metal coordination, as the thiazole ligand is solely coordinated via its nitrogen function. (orig.)

Persistent luminescence and thermoluminescence of UV/VIS -irradiated SrAl2O4: Eu2+, Dy3+ phosphor

International Nuclear Information System (INIS)

Pereyda-Pierre, C.; Meléndrez, R.; García, R.; Pedroza-Montero, M.; Barboza-Flores, M.

2011-01-01

The persistent luminescence and thermoluminescence properties of SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors excited with UV–VIS light in the 200–500 nm region were investigated. The thermoluminescence glow curve was found to be composed of peaks around 70, 125 and 245 °C. The persistent luminescence and thermoluminescence excitation spectra exhibited a broad band around 300–500 nm centered at 400 and 420 nm respectively. A linear behavior of the integrated thermoluminescence intensity and persistent luminescence versus irradiation time was found for the first 60 s. The charge detrapping from the 70 °C trapping levels was the major contributor to the observed persistent luminescence at room temperature. The SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors have suitable properties to be applied as storage and persistent luminescence UV–VIS irradiation dose phosphor. -- Highlights: ► SrAl 2 O 4 :Eu 2+ , Dy 3+ persistent luminescence and thermoluminescence was measured. ► The phosphor was irradiated with UV–VIS photons in the 200–500 nm wavelength range. ► SrAl 2 O 4 :Eu 2+ , Dy 3+ behaves adequately as persistent and storage UV–VIS dosimeter. ► The persistent luminescence dosimetry does not require heat or light stimulation.

The Preparation and Optical Properties of Novel LiLa(MoO42:Sm3+,Eu3+ Red Phosphor

Directory of Open Access Journals (Sweden)

Jiaxi Wang

2018-02-01

Full Text Available Novel LiLa1−x−y(MoO42:xSm3+,yEu3+ (in short: LL1−x−yM:xSm3+,yEu3+ double molybdate red phosphors were synthesized by a solid-state reaction at as low temperature as 610 °C. The optimal doping concentration of Sm3+ in LiLa1−x(MoO42:xSm3+ (LL1−xM:xSm3+ phosphor is x = 0.05 and higher concentrations lead to emission quenching by the electric dipole—electric dipole mechanism. In the samples co-doped with Eu3+ ions, the absorption spectrum in the near ultraviolet and blue regions became broader and stronger than these of the Sm3+ single-doped samples. The efficient energy transfer from Sm3+ to Eu3+ was found and the energy transfer efficiency was calculated. Under the excitation at 403 nm, the chromaticity coordinates of LL0.95−yM:0.05Sm3+,yEu3+ approach to the NTSC standard values (0.670, 0.330 continuously with increasing Eu3+ doping concentration. The phosphor exhibits high luminous efficiency under near UV or blue light excitation and remarkable thermal stability. At 150 °C, the integrated emission intensity of the Eu3+ remained 85% of the initial intensity at room temperature and the activation energy is calculated to be 0.254 eV. The addition of the LL0.83M:0.05Sm3+,0.12Eu3+ red phosphors can improve the color purity and reduce the correlated color temperature of WLED lamps. Hence, LL1−x−yM:xSm3+,yEu3+ is a promising WLED red phosphor.

Effect of UV irradiation on different types of luminescence of SrAl2 O4 :Eu,Dy phosphors.

Science.gov (United States)

Jha, Piyush

2016-11-01

This paper reports the luminescence behavior of Sr 0.097 Al 2 O 4 :Eu 0.01 ,Dy 0.02 phosphors under UV-irradiation. The effect of UV-irradiation on afterglow (AG), thermoluminescence (TL) and mechanoluminescence (ML) of Sr 0.097 Al 2 O 4 :Eu 0.01 ,Dy 0.02 phosphors is investigated. The space group of Sr 0.097 Al 2 O 4 :Eu 0.01 ,Dy 0.02 phosphors is monoclinic P2 1 . The prepared phosphors exhibit a long AG, intense TL and ML. It is found that the AG, ML intensity and TL increase with increasing duration of irradiation time. The ML intensity decreases with successive impact of the load onto the phosphors, whereby the diminished ML intensity can be recovered by UV-irradiation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Tunable luminescence and energy transfer properties of KSr{sub 4}(BO{sub 3}){sub 3}:Dy{sup 3+}, Eu{sup 3+} phosphors for near-UV warm-white LEDs

Energy Technology Data Exchange (ETDEWEB)

Leng, Zhihua; Li, Linlin; Liu, Yali; Zhang, Nannan; Gan, Shucai, E-mail: gansc@jlu.edu.cn

2016-05-15

Dy{sup 3+} and Eu{sup 3+} codoped KSr{sub 4}(BO{sub 3}){sub 3} phosphors were successfully synthesized by solid-state reaction process. Under near-ultraviolet (near-UV) excitation, individual Dy{sup 3+} or Eu{sup 3+} ion activated sample exhibits characteristic emissions in their respective regions. In KSr{sub 4}(BO{sub 3}){sub 3}:Dy{sup 3+}, xEu{sup 3+} phosphors, the energy transfer from Dy{sup 3+} to Eu{sup 3+} was revealed to be resonant type by dipole–dipole mechanism. And the critical distance R{sub Dy–Eu} was calculated to be 13.95 Å. The energy transfer efficiency of KSr{sub 4}(BO{sub 3}){sub 3}:Dy{sup 3+}, xEu{sup 3+} reached about 20% when the concentration of Eu{sup 3+} was 0.035. Moreover, the emitting colors of Dy{sup 3+} and Eu{sup 3+} codoped samples can be adjusted from the edge of white area to warm white via tuning the activator (Eu{sup 3+}) doped concentration. More significantly, the chromaticity coordinates (0.334, 0.351) of KSr{sub 4}(BO{sub 3}){sub 3}:0.005Dy{sup 3+}, 0.015Eu{sup 3+} sample are extremely adjacent to standard white light (0.33, 0.33). The quantum efficiency of the KSr{sub 4}(BO{sub 3}){sub 3}:0.005Dy{sup 3+}, 0.015Eu{sup 3+} phosphor with 389 nm excitation is found to be 42%, demonstrating that the obtained single-component white-emitting phosphor exhibits potential applications for solid state lighting.

Voltage color tunable OLED with (Sm,Eu)-β-diketonate complex blend

Science.gov (United States)

Reyes, R.; Cremona, M.; Teotonio, E. E. S.; Brito, H. F.; Malta, O. L.

2004-09-01

Light emission from organic electroluminescent diodes (OLEDs) in which mixed samarium and europium β-diketonate complexes, [Sm 0.7Eu 0.3(TTA) 3(TPPO) 2], was used as the emitting layer is described. The electroluminescence spectra exhibit narrow peaks arising from 4f-intraconfigurational transitions of the Sm 3+ and Eu 3+ ions and a broad emission band attributed to the electrophosphorescence of the TTA ligand. The intensity ratio of the peaks determined by the bias voltage applied to the OLED, together with the ligand electrophosphorescence, allows to obtain a voltage-tunable color light source.

The Preparation and Optical Properties of Novel LiLa(MoO4)2:Sm3+,Eu3+ Red Phosphor

Science.gov (United States)

Luo, Li; Huang, Baoyu; He, Jingqi; Zhang, Wei; Zhao, Weiren; Wang, Jianqing

2018-01-01

Novel LiLa1−x−y(MoO4)2:xSm3+,yEu3+ (in short: LL1−x−yM:xSm3+,yEu3+) double molybdate red phosphors were synthesized by a solid-state reaction at as low temperature as 610 °C. The optimal doping concentration of Sm3+ in LiLa1−x(MoO4)2:xSm3+ (LL1−xM:xSm3+) phosphor is x = 0.05 and higher concentrations lead to emission quenching by the electric dipole—electric dipole mechanism. In the samples co-doped with Eu3+ ions, the absorption spectrum in the near ultraviolet and blue regions became broader and stronger than these of the Sm3+ single-doped samples. The efficient energy transfer from Sm3+ to Eu3+ was found and the energy transfer efficiency was calculated. Under the excitation at 403 nm, the chromaticity coordinates of LL0.95−yM:0.05Sm3+,yEu3+ approach to the NTSC standard values (0.670, 0.330) continuously with increasing Eu3+ doping concentration. The phosphor exhibits high luminous efficiency under near UV or blue light excitation and remarkable thermal stability. At 150 °C, the integrated emission intensity of the Eu3+ remained 85% of the initial intensity at room temperature and the activation energy is calculated to be 0.254 eV. The addition of the LL0.83M:0.05Sm3+,0.12Eu3+ red phosphors can improve the color purity and reduce the correlated color temperature of WLED lamps. Hence, LL1−x−yM:xSm3+,yEu3+ is a promising WLED red phosphor. PMID:29443910

Measurement of formation cross sections of short-lived nuclei by 14 MeV neutron. Nd, Sm, Dy, Er, Yb

Energy Technology Data Exchange (ETDEWEB)

Sakane, H.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan). School of Engineering; Iida, T.; Takahashi, A.

1997-03-01

Eight neutron activation cross sections producing the nuclei with half-lives between 3 min and 24 min were obtained at the energy range between 13.4 and 14.9 MeV by activation method. The cross sections were {sup 146}Nd(n,p){sup 146}Pr, {sup 154}Sm(n,{alpha}){sup 151}Nd, {sup 162}Dy(n,p){sup 162}Tb, {sup 163}Dy(n,np){sup 162}Tb, {sup 163}Dy(n,p){sup 163}Tb, {sup 164}Dy(n,p){sup 164}Tb, {sup 170}Er(n,{alpha}){sup 167}Dy, {sup 174}Yb(n,p){sup 170}Tm. {sup 163}Dy(n,np){sup 162}Tb (T{sub 1/2}=7.7 min) was obtained for the first time. Present results are compared with previous results and the evaluated data of JENDL-3 and ENDF/B-VI. There are some discrepancies between present results and the JENDL-3 and ENDF/B-VI. (author)

Photoluminescent and Thermoluminescent Studies of Dy3+ and Eu3+ Doped Y2O3 Phosphors.

Science.gov (United States)

Verma, Tarkeshwari; Agrawal, Sadhana

2018-01-01

Eu 3+ doped and Dy 3+ codoped yttrium oxide (Y 2 O 3 ) phosphors have been prepared using solid-state reaction technique (SSR). The prepared phosphors were characterized by X-ray diffractometer (XRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR) techniques. Photoluminescence (PL) and Thermoluminescence (TL) properties were studied in detail. PL emission spectra were recorded for prepared phosphors under excitation wavelength 254 nm, which show a high intense peak at 613 nm for Y 2 O 3 :Dy 3+ , Eu 3+ (1:1.5 mol %) phosphor. The correlated color temperature (CCT) and CIE analysis have been performed for the synthesized phosphors. TL glow curves were recorded for Eu 3+ doped and Dy 3+ codoped phosphors to study the heating rate effect and dose response. The kinetic parameters were calculated using peak shape method for UV and γ exposures through computerized glow curve deconvolution (CGCD) technique. The phosphors show second order kinetics and activation energies varying from 5.823 × 10 - 1 to 18.608 × 10 - 1  eV.

Induced assembly and photoluminescence of lanthanum (Tb, Eu, Dy) complexes/ZnO/polyethylene glycol hybrid phosphors

Energy Technology Data Exchange (ETDEWEB)

Yan Bing [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn; Chen Xi [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China); Wu Jianhua [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China)

2007-08-31

Some novel kinds of hybrid phosphors were assembled with lanthanum (Tb, Eu, Dy) complexes (with four kinds of terbium complexes is 2,4-dihydroxybenzonic acid (DHBA), 1,10-phenanthroline (phen), acetylacetone (AA) and nicotinic acid (Nic), respectively) doped ZnO/PEG particles by co-precipitation approach derived from Zn(CH{sub 3}COO){sub 2} (Zn(AC){sub 2}), NaOH, PEG as precursors at room temperature. The characteristic luminescence spectra for f-f transitions of Tb{sup 3+}, Eu{sup 3+}, Dy{sup 3+} were observed. It is worthy to point out that ZnO is the excellent host for lanthanum ions by the assembly of PEG matrices.

An electrochemical approach for removal of radionuclidic contaminants of Eu from 153Sm for effective use in metastatic bone pain palliation.

Science.gov (United States)

Chakravarty, Rubel; Chakraborty, Sudipta; Khan, Mohammed Sahiralam; Ram, Ramu; Sarma, Haladhar Dev; Dash, Ashutosh

2018-03-01

Thermal neutron activation of 152 Sm [ 152 Sm(n,γ) 153 Sm] using natural or isotopically enriched (by 152 Sm) samarium target is the established route for production of 153 Sm used for preparation of 153 Sm-EDTMP for pain palliation in cancer patients with disseminated bone metastases. However, some long-lived radionuclidic contaminants of Eu, such as, 154 Eu (t ½ =8.6y) are also produced during the target activation process. This leads to detectable amount of Eu radionuclidic contaminants in patients' skeleton even years after administration with therapeutic doses of 153 Sm-EDTMP. Further, the presence of such contaminants in 153 Sm raises concerns related to radioactive waste management. The aim of the present study was to develop and demonstrate a viable method for large-scale purification of 153 Sm from radionuclidic contaminants of Eu. A radiochemical separation procedure adopting electroamalgamation approach has been critically evaluated. The influence of different experimental parameters for the quantitative removal radionuclidic contaminants of Eu from 153 Sm was investigated and optimized. The effectiveness of the method was demonstrated by purification of ~37 GBq of 153 Sm in several batches. As a proof of concept, 153 Sm-EDTMP was administered in normal Wistar rats and ex vivo γ-spectrometry of bone samples were carried out. After carrying out the electrolysis under the optimized conditions, the radionuclidic contaminants of Eu could not be detected in purified 153 Sm solution by γ-spectrometry. The overall yield of 153 Sm obtained after the purification process was >85%. The reliability of this approach was amply demonstrated in several batches, wherein the performance remained consistent. Ex vivo γ-spectrometry of bone samples of Wistar rats administered with 153 Sm-EDTMP (prepared using electrochemically purified 153 Sm) did not show photo peaks corresponding to radionuclidic contaminants of Eu. A viable electrochemical strategy for the large

The photoluminescent properties of Y2O3:Bi3+, Eu3+, Dy3+ phosphors for white-light-emitting diodes.

Science.gov (United States)

Han, Xiumei; Feng, Xu; Qi, Xiwei; Wang, Xiaoqiang; Li, Mingya

2014-05-01

Bi3+, Eu3+, Dy3+ activated Y2O3 phosphors were prepared through the sol-gel process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The XRD patterns show the refined crystal structure of Y2O3. The energy transfer processes of Bi(3+)-Eu3+ occurred in the host lattices. The thermal stability of Y2O3:Bi3+, Eu3+, Dy3+ phosphors was studied. Under short wavelength UV excitation, the phosphors show excellent characteristic red, blue, and yellow emission with medium intensity.

Sol–gel assisted synthesis and photoluminescence property of Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}, Dy{sup 3+} red phosphor for white light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wentao, E-mail: zhangwentao2005@163.com [College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China); Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions, Chengdu 610059 (China); Wang, Yulong; Gao, Yang [College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China); Long, Jianping [College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China); Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions, Chengdu 610059 (China); Li, Junfeng [College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China)

2016-05-15

Eu{sup 2+}, Dy{sup 3+} co-doped Sr{sub 2}Si{sub 5}N{sub 8} red phosphors were prepared using a sol–gel-nitridation method at a lower temperature comparing with traditional solid state reaction. Effects of synthesis process, Eu{sup 2+} and Dy{sup 3+} doping concentration on the crystal structure and luminescence property of as-prepared phosphors were investigated. X-ray diffraction patterns indicated that all Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}, Dy{sup 3+} phosphors have the standard phase of Sr{sub 2}Si{sub 5}N{sub 8} structure. With a broad excitation from UV to blue light, a strong emission of Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}, Dy{sup 3+} with 4f{sup 6}5d{sup 1}→4f{sup 7} transition of Eu{sup 2+} ions was obtained at red region in photoluminescence spectra. Emission peaks in spectra were red-shifted from 611 to 632 nm for all Sr{sub 2}Si{sub 5}N{sub 8}:xEu{sup 2+} as Eu{sup 2+} ion concentrations increased, which due to Eu{sup 2+} ions occupying from the tenfold coordinated site (Sr1) to the eightfold coordinated site (Sr2). These Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+} phosphors with Dy{sup 3+} co-doping showed excellent luminescence properties, included emission intensity and luminescence quenching. It is potential that Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}, Dy{sup 3+} phosphors can be applied in white LEDs combining with blue InGaN LEDs. - Highlights: • Eu{sup 2+}/Dy{sup 3+} co-doped Sr{sub 2}Si{sub 5}N{sub 8} red phosphor were prepared by sol–gel-nitridation. • Sol–gel-nitridation method decreased the crystallization temperature of Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}, Dy{sup 3+} effectively. • Luminescence properties of Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+} were improved obviously by Dy{sup 3+} co-doping. • Luminescence properties of Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}, Dy{sup 3+} phosphors are superior to commercial Y{sub 2}O{sub 2}S:Eu{sup 3+}.

Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

Science.gov (United States)

Nair, Govind B; Dhoble, S J

2016-09-01

Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs.

Site selective spectroscopy in BaYF{sub 5}:RE{sup 3+} (RE = Eu, Sm) nano-glass–ceramics

Energy Technology Data Exchange (ETDEWEB)

Castillo, J. del, E-mail: fjvargas@ull.edu.es [Dpto. Física, Universidad de La Laguna, 38206 La Laguna, Tenerife (Spain); Yanes, A.C. [Dpto. Física, Universidad de La Laguna, 38206 La Laguna, Tenerife (Spain); Abe, S.; Smet, P.F. [LumiLab, Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000 Gent (Belgium); Center for Nano- and Biophotonics (NB Photonics), Ghent University (Belgium)

2015-06-25

Highlights: • We obtained sol–gel transparent nGCs with Eu{sup 3+}, Sm{sup 3+}-doped cubic BaYF{sub 5} nanocrystals. • Eu{sup 3+}-doped BaYF{sub 5} NCs were prepared by solvothermal method. • Their luminescent properties were studied and compared with the Eu{sup 3+}-doped nGCs. • Eu{sup 3+}/Sm{sup 3+} were used as probe ions in the nGCs to distinguish different environments. • The incorporation of a large fraction of RE ions into the BaYF{sub 5} NCs was confirmed. - Abstract: Trivalent rare-earth (RE = Eu, Sm) doped transparent nano-glass–ceramics comprising BaYF{sub 5} nanocrystals were successfully obtained by appropriate heat-treatment of the corresponding precursor sol–gel glasses. Their structural and spectroscopic properties were investigated and compared with those for Eu{sup 3+}-doped-BaYF{sub 5} nanocrystals prepared by a solvothermal method. X-ray Diffraction, Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy measurements confirmed the distribution of BaYF{sub 5} nanocrystals in the glass matrix, presenting a cubic phase structure with space group Fm-3m. In order to achieve a further structural characterization, the luminescence properties of the Eu{sup 3+} and Sm{sup 3+} dopants were also used as sensitive probes. The reduction in the emission intensities of hypersensitive transitions {sup 5}D{sub 0} → {sup 7}F{sub 2} and {sup 4}G{sub 5/2} → {sup 6}H{sub 9/2} for Eu{sup 3+} and Sm{sup 3+} ions respectively, along with time-resolved measurements, confirm the distribution of a significant fraction of RE ions into the fluoride nanocrystal environment. These results suggest that BaYF{sub 5} nano-glass–ceramics doped with Eu{sup 3+} or Sm{sup 3+} can be considered as potential red-emitting phosphors for the development of white LEDs under near UV excitation.

Phase relations and linear thermal expansion of cubic solid solutions in the Th1-xMxO2-x/2 (M=Eu, Gd, Dy) systems

International Nuclear Information System (INIS)

Mathews, M.D.; Ambekar, B.R.; Tyagi, A.K.

2005-01-01

Cell parameters and linear thermal expansion studies of the Th-M oxide systems with general compositions Th 1-x M x O 2-x/2 (M=Eu 3+ , Gd 3+ and Dy 3+ , 0.0= 1.5 in the ThO 2 lattice. The upper solid solubility limits of EuO 1.5 , GdO 1.5 and DyO 1.5 in the ThO 2 lattice under conditions of slow cooling from 1673K are represented as Th 0.50 Eu 0.50 O 1.75 , Th 0.60 Gd 0.40 O 1.80 and Th 0.85 Dy 0.15 O 1.925 , respectively. The linear thermal expansion (293-1123K) of MO 1.5 and their single-phase solid solutions with thoria were investigated by dilatometery. The average linear thermal expansion coefficients (α-bar ) of the compounds decrease on going from EuO 1.5 to DyO 1.5 . The values of α-bar for EuO 1.5 , GdO 1.5 and DyO 1.5 containing solid solutions showed a downward trend as a function of the dopant concentration. The linear thermal expansion (293-1473K) of the solid solutions investigated by high-temperature XRD also showed a similar trend

Luminescence properties of NaY(WO{sub 4}){sub 2}:Sm{sup 3+}, Eu{sup 3+} phosphors prepared by molten salt method

Energy Technology Data Exchange (ETDEWEB)

Liu, Ting; Meng, Qingyu, E-mail: qingyumeng163@163.com; Sun, Wenjun

2016-02-15

Sm{sup 3+} singly doped NaY(WO{sub 4}){sub 2} and Sm{sup 3+}, Eu{sup 3+} co-doped NaY(WO{sub 4}){sub 2} phosphors have been synthesized by molten salt method. The crystal structure and morphology were characterized by means of X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). In Sm{sup 3+} singly doped NaY(WO{sub 4}){sub 2} phosphors, the suitable doping concentration was proved. In Sm{sup 3+}, Eu{sup 3+} co-doped NaY(WO{sub 4}){sub 2} phosphors, the energy transfer from Sm{sup 3+} to Eu{sup 3+} is confirmed by the luminescent spectra. A strong absorption line at 405 nm can be generated from {sup 6}H{sub 5/2}-{sup 4}K{sub 11/2} ({sup 4}F{sub 7/2}) transition of Sm{sup 3+} in Sm{sup 3+}, Eu{sup 3+} co-doped NaY(WO{sub 4}){sub 2} phosphors, which is suitable for the emission of the near-ultraviolet light-emitting diodes. The energy transfer efficiency, energy transfer rate and average distance between Sm{sup 3+} and Eu{sup 3+} in the NaY(WO{sub 4}){sub 2}:Sm{sup 3+}, Eu{sup 3+} phosphors have been calculated based on the fluorescent dynamic analysis. Finally, the energy transfer mechanism between Sm{sup 3+} and Eu{sup 3+} is confirmed, the energy transfer occurs between {sup 4}G{sub 5/2} state of Sm{sup 3+} ions and {sup 5}D{sub 0} state rather than {sup 5}D{sub 1} state of Eu{sup 3+} ions.

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

Directory of Open Access Journals (Sweden)

Allu Amarnath Reddy

2013-02-01

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

Phosphorescent and thermoluminescent properties of SrAl2O4:Eu2+, Dy3+ phosphors prepared by solid state reaction method

International Nuclear Information System (INIS)

Mothudi, B.M.; Ntwaeaborwa, O.M.; Kumar, A.; Sohn, K.; Swart, H.C.

2012-01-01

Long persistent SrAl 2 O 4 :Eu 2+ phosphors co-doped with Dy 3+ were prepared by the solid state reaction method. The main diffraction peaks of the monoclinic structure of SrAl 2 O 4 were observed in all the samples. The broad band emission spectra at 497 nm for SrAl 2 O 4 :Eu 2+ , Dy 3+ were observed and the emission is attributed to the 4f 6 5d 1 to 4f 7 transition of Eu 2+ ions. The samples annealed at 1100–1200 °C showed similar broad TL glow curves centered at 120 °C. The similar TL glow curves suggest that the traps responsible for them are similar. The long afterglow displayed by the phosphors annealed at different temperatures, may be attributed to the Dy 3+ ions acting as the hole trap levels, which play an important role in prolonging the duration of luminescence.

White-emission in single-phase Ba2Gd2Si4O13:Ce3 +,Eu2 +,Sm3 + phosphor for white-LEDs

Science.gov (United States)

Jiang, Xiumin; Zhang, Yuqian; Zhang, Jia

2018-03-01

To develop new white-light-emitting phosphor, a series of Ce3 +-Eu2 +-Sm3 + doped Ba2Gd2Si4O13 (BGS) phosphors were prepared by the solid-state reaction method, and their photoluminescence properties were studied. The Ce3 + and Eu2 + single-doped BGS show broad emission bands around in the region of 350-550 and 420-650 nm, respectively. By co-doping Ce3 +-Eu2 + into BGS, the energy transfer (ET) from Ce3 + to Eu2 + is inefficient, which could be due to the competitive absorption between the two activator ions. The Sm3 +-activated BGS exhibits an orangey-red emission in the region of 550-750 nm. To achieve white emission, the BGS:0.06Ce3 +,0.04Eu2 +,ySm3 + (0 ≤ y ≤ 0.18) phosphors were designed, in which the ET from Ce3 +/Eu2 + to Sm3 + was observed. The emission color can be tuned by controlling the Sm3 + concentration, and white emission was obtained in the BGS:0.06Ce3 +,0.04Eu2 +,0.06Sm3 + sample. The investigation of thermal luminescence stability for the typical BGS:0.06Ce3 +,0.04Eu2 +,0.06Sm3 + sample reveals that the emission intensities of both Eu2 + and Sm3 + demonstrate continuous decrease but the Ce3 + emission is enhanced gradually with increasing temperature. The corresponding reason has been discussed.

Combustion synthesis and characterization of blue long lasting phosphor CaAl2O4: Eu2+, Dy3+ and its novel application in latent fingerprint and lip mark detection

Science.gov (United States)

Sharma, Vishal; Das, Amrita; Kumar, Vijay; Kumar, Vinay; Verma, Kartikey; Swart, H. C.

2018-04-01

This work investigates the structural, optical and photometric characterization of a Eu2+/Dy3+ doped calcium aluminates phosphor (CaAl2O4: Eu2+/Dy3+) for finger and lip print detections. Synthesis of CaAl2O4: Eu2+/Dy3+ (CAED) phosphors were carried out via a combustion synthesis method with urea as a fuel. Eu2+/Dy3+ doped CaAl2O4 phosphors have been studied with X-ray diffraction (XRD, Energy Dispersive X-Ray Spectroscopy Selected Area Diffraction (SAED) and High resolution Transmission Electron Microscope (HR-TEM). The XRD pattern shows that the synthesized Eu2+/Dy3+ doped CaAl2O4 phosphor have a single monoclinic structure and show that the addition of the dopant/co-dopants didn't change the crystal structure. The formation of monoclinic phase was confirmed by the selected area diffraction pattern. The TEM micrograph displays the morphology of the synthesized Eu2+/Dy3+ doped CaAl2O4 phosphors as spherical particles with an average particle size of 33 nm. The optical band gap was calculated using the diffuse reflectance for the synthesized nanophosphor powders. The photoluminescence emission spectra was recorded for the synthesized powder, with an excitation wavelength of 326 nm and the major bands was recorded at 447 nm corresponding to the blue color and two minor bands were recorded at 577 nm and 616 nm. To the best of our knowledge, this work is the first to show the use of CaAl2O4: Eu2+/Dy3+ nanophosphor in developing latent fingerprint and lip print effectively.

Optical properties of lithium magnesium borate glasses doped with Dy3+ and Sm3+ ions

International Nuclear Information System (INIS)

Yasser Saleh Mustafa Alajerami; Suhairul Hashim; Wan Muhamad Saridan Wan Hassan; Ahmad Termizi Ramli; Azman Kasim

2012-01-01

Several studies showed the interesting properties of trivalent lanthanide ions when doped in various types of glasses. Optical and physical properties of lithium magnesium borate glasses doped with Dy 3+ then with Sm 3+ ions were determined by measuring their absorption and luminescence spectra in the visible region. The absorption spectra of Dy 3+ showed eight absorption bands with hypersensitive transition at 1265 nm ( 6 H 15/2 → 6 F 11/2 - 6 H 9/2 ) and three PL emission bands at 588 nm ( 4 F 9/2 → 6 H 15/2 ), 660 nm ( 4 F 9/2 → 6 H 13/2 ) and 775 nm ( 4 F 9/2 → 6 H 11/2 ). Regarding the Sm3 + , nine absorption bands were observed with hypersensitive transition at 1237 nm ( 6 H 5/2 - 6 F 7/2 ); the PL spectrum showed four prominent peaks at 4 G 5/2 → 6 H 5/2 (yellow color), 4 G 5/2 → 6 H 7/2 (bright orange color), 4 G 5/2 → 6 H 9/2 (orange reddish color) and 4 G 5/2 → 6 H 11/2 (red color), respectively. Finally, a series of physical parameters such as the oscillator strengths, refractive index, ions concentration, Polaron radius and other parameters were calculated for each dopant.

Hydrothermal synthesis, characterization, and luminescence of Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers

International Nuclear Information System (INIS)

Yang, Li; Wan, Yingpeng; Li, Yuze; Pu, Yinfu; Huang, Yanlin; Chen, Cuili; Seo, Hyo Jin

2016-01-01

Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers were synthesized by the hydrothermal reaction method. The structural refinement was conducted on the base of the X-ray powder diffraction (XRD) measurements. The surface properties of the Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers were investigated by the measurements such as the scanning electron microscope (SEM), transmission electron microscope (TEM), and the energy dispersive spectrum (EDS). The nanofiber has a diameter of about 100 nm and a length of several micrometers. The luminescence properties such as photoluminescence excitation (PLE) and emission spectra (PL), decay lifetime, color coordinates, and the absolute internal quantum efficiency (QE) were reported. Ca_2B_2O_5:Eu"3"+ nanofibers show the red luminescence with CIE coordinates of (x = 0.41, y = 0.51) and the luminescence lifetime of 0.63 ms. The luminescence of Ca_2B_2O_5:Tb"3"+ nanofibers is green color (x = 0.29, y = 0.53) with the lifetime of 2.13 ms. However, Dy"3"+-doped Ca_2B_2O_5 nanofibers present a single-phase white-color phosphor with the fluorescence decay of 3.05 ms. Upon near-UV excitation, the absolute quantum efficiency is measured to be 65, 35, and 37 % for Eu"3"+-, Tb"3"+-, Dy"3"+-doped Ca_2B_2O_5 nanofibers, respectively. It is suggested that Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers could be an efficient phosphor for lighting and display.

Crystal structure and magnetic properties of RCu5-xPdx (R=Pr, Nd, Sm and Eu) alloys

International Nuclear Information System (INIS)

Shah, K.V.; Bonville, P.; Manfrinetti, P.; Provino, A.; Dhar, S.K.

2009-01-01

We report the effect of replacing Cu by Pd in RCu 5 (R=Pr, Nd, Sm and Eu). The parent RCu 5 compounds crystallize in the hexagonal CaCu 5 -type structure. The hexagonal symmetry is retained in PrCu 4 Pd and EuCu 5-x Pd x (x=1 and 2) but the crystal structure changes to cubic AuBe 5 -type in PrCu 3 Pd 2 , NdCu 5-x Pd x (x=1 and 2) and SmCu 4 Pd. Substitution with Pd leads to lattice expansion and modifies the magnetic behavior. While PrCu 5 is known to be a van-Vleck paramagnet with a singlet ground state, PrCu 4 Pd and PrCu 3 Pd 2 show ferromagnetic-like behavior at low temperatures. SmCu 4 Pd orders ferromagnetically near 28 K in contrast to the antiferromagnetic nature of the parent SmCu 5 . The divalent nature of the Eu ions in EuCu 5 is retained in the ternary alloys, but the Curie temperature is reduced from 57 to 24.5 and 14.5 K in EuCu 4 Pd and EuCu 3 Pd 2 , respectively, inferred from the location of peak in the heat capacity of these two compounds. The magnetic hyperfine field at the Eu nucleus measured with 151 Eu Moessbauer spectroscopy in the ternary Eu-alloys is comparable to that in EuCu 5 . The magnetic behavior of NdCu 4 Pd is similar to that reported in NdCu 5 . The zero-field-cooled, low-field magnetization of NdCu 3 Pd 2 shows a region of diamagnetic behavior roughly between 21 and 4 K, but the field-cooled response is positive.

Shape tunable synthesis of Eu- and Sm-doped ZnO microstructures ...

Indian Academy of Sciences (India)

Shape tunable synthesis of Eu- and Sm-doped ZnO microstructures: a morphological ... different microstructures material at relatively low temper- ..... Chem. C 114. 2776. 5. Gao P X and Wang Z L 2003 J. Am. Chem. Soc. 125 11299. 6.

Luminescent processes in SrAl2O4: Eu2+, Dy3+ phosphors exposed to ultraviolet radiation

International Nuclear Information System (INIS)

Arellano T, O.; Castaneda, B.; Pedroza M, M.; Melendrez, R.; Chernov, V.; Barboza F, M.; Yen, W.M.

2006-01-01

The long persistent response of the SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors has been utilized in the development of new luminescent devices with low voltage requirements, incorporated in luminous paints and emergency light illumination. We have studied the experimental characteristics of thermoluminescence (TL) and afterglow (AG) processes in UV irradiated long persistent phosphors SrAl 2 O 4 : Eu 2+ , Dy 3+ . The TL signal is achieved by thermal stimulation of material and it involves the release of trapped charge carriers in the form of electrons and/or electrons and holes generated by irradiation exposure of the dosimetric materials, while the AG signal is obtained at RT without thermal stimulation. In both cases, the intensity of the response is proportional to the radiation dose. For our UV irradiated SrAl 2 O 4 : Eu 2+ , Dy 3+ samples, the TL glow curve depicted at least five peaks around 318, 424, 457, 488 and 515 K with activation energy values of 0.28, 0.67, 1.00, 1.35 and 1.62 eV, respectively. In this respect, the initial rise method was used to estimate experimentally the peak positions. Then, these experimental data were used as initial values to determine the kinetics parameters through a computer deconvolution and fitting process. Besides, the AG response was analyzed and we found it has at least three exponential processes with different lifetimes around 56, 180 and 1230 s, respectively. In addition, the afterglow dosimetry performance of this SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphor exhibited a linear behavior for the first fifty seconds of ultraviolet irradiation. For higher ultraviolet time exposure the behavior is sub linear with no apparent saturation during ten minutes. The afterglow dosimetry response was performed with a source of 400 nm that corresponds to the main band component of the afterglow excitation spectrum in the 250-500 nm range. The TL glow intensity peaked at 460 K and AG intensity responses are strongly dependents on the excitation

Crossrelaxations and non-radiative energy transfer from (4G5/2) Sm3+ → (5D0) Eu3+: B2O3–ZnO glasses

International Nuclear Information System (INIS)

Naresh, V.; Rudramadevi, B.H.; Buddhudu, S.

2015-01-01

Graphical abstract: The energy transfer process occurring from Sm 3+ to Eu 3+ in B 2 O 3 –ZnO (BZn) glasses is analyzed. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm 3+ and Eu 3+ has been demonstrated from the spectral overlap of Eu 3+ absorption and Sm 3+ emission, photoluminescence spectra, energy level diagram and lifetime measurements. The energy transfer mechanism in (Sm 3+ + Eu 3+ ) co-doped glass is governed by dipole–dipole interaction. - Highlights: • Spectroscopic properties of individually doped Sm 3+ , Eu 3+ & co-doped (Sm 3+ + Eu 3+ ) in BZn glasses were studied separately. • The effect of Eu 3+ concentration on luminescence properties is explained from cross-relaxations. • Energy transfer from Sm 3+ ( 4 G 5/2 ) to Eu 3+ ( 5 D 0 ) has been explained from Foster–Dexter theory. • Dipole–dipole mechanism governs the energy transfer from Sm 3+ to Eu 3+ . - Abstract: The present paper reports on the results concerning to photoluminescence features of Eu 3+ , Sm 3+ ions and energy transfer process occurring from Sm 3+ to Eu 3+ doped in 45 B 2 O 3 –55 ZnO (BZn) glasses prepared by melt quenching technique. Luminescence quenching as a function of Eu 3+ concentration in BZn glasses has been discussed. Among the studied concentrations, 0.5 mol% of Eu 3+ is optimized because it has exhibited red emission transition 5 D 0 → 7 F 2 . With regard to Sm 3+ glasses, orange emission at 602 nm ( 4 G 5/2 → 6 H 7/2 ) has been noticed on exciting with λ exci = 403 nm. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm 3+ and Eu 3+ has been explained from the spectral overlap of Eu 3+ absorption and Sm 3+ emission. The optimized concentration 0.5 mol% of Eu 3+ is co-doped with Sm 3+ in various concentrations ranging from 0.1 to 1.5 mol% inorder to study the sensitization effect of Sm 3+ on Eu 3+ luminescence. The results have revealed that with the addition of Sm 3+ to Eu 3+ : BZn

Narrow spectral emission CaMoO{sub 4}: Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+} phosphor crystals for white light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Khanna, A. [Smart Lighting Engineering Research Center, 110, 8th Street, Troy, New York, 12180 (United States); Electrical, Computer and Systems Engineering Department, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, New York, 12180 (United States); Dutta, P.S., E-mail: duttap@rpi.edu [Smart Lighting Engineering Research Center, 110, 8th Street, Troy, New York, 12180 (United States); Electrical, Computer and Systems Engineering Department, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, New York, 12180 (United States)

2013-02-15

Alkaline earth metal molybdates are promising candidates as a host material for high efficiency narrow spectral emission phosphors. These phosphors could potentially be used for the fabrication of phosphor-converted light emitting diodes (pc-LEDs). Phosphor crystals of calcium molybdate doped with rare earth dopant Ln{sup 3+}(Ln=Eu, Dy, Tb) grown using flux growth method have been shown to exhibit higher excitation efficiency than the powders synthesized by solid-state reaction process. Molybdenum (VI) oxide has been found to be a suitable flux for growing large size optically transparent high quality crystals at a temperature around 1100 Degree-Sign C. Using the excitation wavelengths of 465 nm, 454 nm and 489 nm for CaMoO{sub 4}: Eu{sup 3+}, CaMoO{sub 4}: Dy{sup 3+} and CaMoO{sub 4}: Tb{sup 3+}, respectively, intense emission lines at wavelengths of 615 nm, 575 nm and 550 nm were observed. The optimized doping concentrations of 12%, 2% and 5% for Eu{sup 3+}, Dy{sup 3+} and Tb{sup 3+}, respectively, provided the highest luminescence intensity. - Graphical Abstract: CaMoO{sub 4}: Eu{sup 3+} phosphor crystals grown using a molybdenum (VI) oxide flux exhibited around 1.5 times the emission intensity of powders obtained from solid-state reaction at the same synthesis temperature. These crystals were found to efficiently emit 615 nm red light when excited by near UV light up to a wavelength of 395 nm. Highlights: Black-Right-Pointing-Pointer CaMoO{sub 4}: Ln{sup 3+} (Ln=Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+}) phosphor crystals were successfully grown using high temperature flux (solutions) containing molybdenum (VI) oxide or lithium chloride. Black-Right-Pointing-Pointer Narrow spectral emission at 615 nm, 575 nm and 550 nm, respectively, was observed from CaMoO{sub 4}: Ln{sup 3+} (Ln=Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+}) phosphor crystals. Black-Right-Pointing-Pointer The optimized doping concentrations of Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+} in CaMoO{sub 4} for highest

Thermoluminescence of SrAl_2O_4:Eu"2"+, Dy"3"+: dosimetric characteristics and evidence of glow-peak collocation

International Nuclear Information System (INIS)

Chithambo, M.L.

2016-01-01

The thermoluminescence of SrAl_2O_4:Eu"2"+, Dy"3"+ consists of collocated peaks whereby a dominant component subsumes subsidiary ones to such an extent that they appear as one; Qualitative and quantitative analysis of such cases will be described with suitable illustrative examples. The general features and qualitative kinetics properties of thermoluminescence from SrAl_2O_4:Eu"2"+, Dy"3"+ is reported. Measurements using X-ray excited optical luminescence show that stimulated luminescence from SrAl_2O_4:Eu"2"+, Dy"3"+ has two prominent emission bands, one at 475 nm and a more intense one near 575 nm, studied in this work. There are also weaker intensity emissions at 405, 510, 600 and 660 nm. The natural thermoluminescence measured at 1°C s"-"1 shows three peaks at 74, 170 and 340°C whereas 20 Gy beta-irradiation produces TL dominated by a single peak at 34°C. Analysis of this peak for its order of kinetics produces somewhat inconclusive results. The results of the partial heating procedure T_m - T_s_t_o_p are consistent with both first and second-order kinetics. On the other hand, the position of the peak is independent of dose for several ranges of doses implying that the apparently single peak consists of multiple first-order peaks. Complementary investigations using the fractional glow technique, resolution by isothermal heating and the effect of fading on the peak show that the glow-curve of SrAl_2O_4:Eu"2"+, Dy"3"+ comprises closely collocated thermoluminescence peaks. The implication of such complexity on kinetic analysis on this material and others that share this feature will be discussed. (author)

Optical study of SrAl1.7B0.3O4:Eu, R (R=Nd, Dy) pigments with long-lasting phosphorescence for industrial uses

International Nuclear Information System (INIS)

Sanchez-Benitez, J.; Andres, A. de; Marchal, M.; Cordoncillo, E.; Regi, M.V.; Escribano, P.

2003-01-01

We have studied and compared the optical properties of SrAl 1.7 B 0.3 O 4 :Eu, R (R=Nd, Dy) pigments that present long-lasting phosphorescence obtained by different synthesis techniques. Samples obtained by ceramic methods, in our laboratories and by an industrial process, present better phosphorescent properties than those obtained by sol-gel technique. Raman spectra show that grinding produces severe damage of the lattice. We have obtained and analyzed the Eu 3+ crystal field luminescence indicating that Eu 3+ is found in quite different sites comparing ceramic and sol-gel samples. Codoping, with Nd or Dy is necessary in order to reduce the Eu 3+ content, in all cases. The green luminescence band, obtained under UV illumination, can be fitted to two and three components in ceramic and sol-gel samples, respectively, due to different Eu 2+ sites. Eu-Dy samples present the longest and the most efficient phosphorescence. The time evolution of the afterglow is well described by a t -1 law, up to about 2 h, indicating that the recombination process is achieved by electron-hole tunneling

Photoluminescent properties of LiSrxBa1-xPO4:RE3+ (RE = Sm3+, Eu3+) f-f transition phosphors

International Nuclear Information System (INIS)

Tu Dong; Liang Yujun; Liu Rong; Cheng Zheng; Yang Fan; Yang Wenlong

2011-01-01

Highlights: → Novel phosphors LiSr x Ba 1-x PO 4 : Sm 3+ and LiSr x Ba 1-x PO 4 : Eu 3+ have been synthesized by solid-state reaction method. → The LiSr x Ba 1-x PO 4 : Sm 3+ and LiSr x Ba 1-x PO 4 : Eu 3+ phosphors may be potential f-f transition phosphors used in LED. → The emission intensity of the LiSr x Ba 1-x PO 4 : Sm 3+ and LiSr x Ba 1-x PO 4 : Eu 3+ phosphors can be enhanced by increasing the value of x. - Abstract: Rare-earth ions (Sm 3+ or Eu 3+ ) doped LiSr x Ba 1-x PO 4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) f-f transition phosphor powders were prepared by a high temperature solid-state reaction. The resulted phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The results of XRD indicate that the phase structure of the sample changes from LiBaPO 4 to LiSrPO 4 when x changes from 0 to 1.0. The excitation spectra indicate that only direct excitation of rare earth ions (Sm 3+ or Eu 3+ ) can be observed. The doped rare earth ions show their characteristic emission in LiSr x Ba 1-x PO 4 , i.e., Eu 3+5 D 0 - 7 F J (J = 0, 1, 2, 3, 4), Sm 3+4 G 5/2 → 6 H J (J = 5/2, 7/2, 9/2, 11/2), respectively. The dependence of the emission intensities of the LiSr x Ba 1-x PO 4 :Sm 3+ and LiSr x Ba 1-x PO 4 :Eu 3+ phosphors on the x value and Ln 3+ (Ln 3+ = Sm 3+ , Eu 3+ ) concentration is also investigated.

Extraction of Dy(III and Sm(III with N,N’-dimethyl-N,N’-dioctylsuccinamide

Directory of Open Access Journals (Sweden)

ZHANG ZHENWEI

2005-02-01

Full Text Available This work was focused on the applicability of a new diamide N,N’-dimethyl- N,N’-dioctylsuccinamide (DMDOSA employing cyclohexane as the diluent to extract Dy(III and Sm(III from nitric acid solutions. The extraction from HNO3 was investigated by distributionmeasurements. The stoichiometry of the predominant adducts of DMDOSA with HNO3 is 1:1 (HNO3 .DMDOSA under the studied conditions. The effect of the concentrations of nitric acid, lithium nitrate and extractant on the distribution ratio was investigated. An IR spectral study was also made of the extracted species.

Photoluminescence characterization of Dy3+ and Eu2+ ion in M5(PO4)3F (M = Ba, Sr, Ca) phosphors

International Nuclear Information System (INIS)

Nagpure, I.M.; Shinde, K.N.; Dhoble, S.J.; Kumar, Animesh

2009-01-01

Photoluminescence investigation of Eu and Dy activated phosphate based phosphors prepared by combustion synthesis, characterized by XRD (X-ray diffraction) and photoluminescence techniques, has been reported. PL excitation spectrum of M 5 (PO 4 ) 3 F:Dy phosphors shows the excitation peaks ranging from 300 to 400 nm due to 4f → 4f transitions of Dy 3+ ions. PL emission spectrum of Dy 3+ ion under 348 nm excitation gives PL emission at 482 nm (blue) due to 4 F 9/2 → 6 H 15/2 transitions, 574 nm (yellow) emission due to 4 F 9/2 → 6 H 13/2 transitions and 670 nm (red) due to 4 F 9/2 → 6 H 11/2 transitions, gives BYR (blue-yellow-red) emissions. The Eu 2+ broad band PL emission spectrum was observed in M 5 (PO 4 ) 3 F:Eu phosphor at 440 nm in the blue region of the spectrum due to 5d → 4f transition at 352 nm excitation. The 300-400 nm is Hg-free excitation (Hg excitation is 85% 254 nm wavelength of light and 15% other wavelengths), which is characteristic of solid-state lighting phosphors. Hence PL emission in divalent europium and trivalent dysprosium may be efficient photoluminescent materials for solid-state lighting phosphors.

Photoluminescence and phosphorescence properties of MAl2O4:Eu2+, Dy3+ (M=Ca, Ba, Sr) phosphors prepared at an initiating combustion temperature of 500 deg. C

International Nuclear Information System (INIS)

Mothudi, B.M.; Ntwaeaborwa, O.M.; Botha, J.R.; Swart, H.C.

2009-01-01

Eu 2+ and Dy 3+ co-doped calcium aluminate, barium aluminate and strontium aluminate phosphors were synthesized at an initiating combustion temperature of 500 deg. C using urea as an organic fuel. The crystallinity of the phosphors was investigated by using X-ray diffraction (XRD) and the morphology was determined by a scanning electron microscope (SEM). The low temperature monoclinic structure for both CaAl 2 O 4 and SrAl 2 O 4 and the hexagonal structure of BaAl 2 O 4 were observed. The effect of the host materials on the photoluminescence (PL) and phosphorescence properties were investigated by using a He-Cd Laser and a Cary Eclipse fluorescence spectrophotometer, respectively. The broad band emission spectra observed at 449 nm for CaAl 2 O 4 :Eu 2+ , Dy 3+ , 450 nm (with a shoulder-peak at 500 nm) for BaAl 2 O 4 :Eu 2+ , Dy 3+ and 528 nm for SrAl 2 O 4 :Eu 2+ , Dy 3+ are attributed to the 4f 6 5d 1 to 4f 7 transition in the Eu 2+ ion in the different hosts.

Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

Energy Technology Data Exchange (ETDEWEB)

Mishra, A; Singh, M P; Singh, V K

1982-05-01

The nitrato-complexes, (Y(PyBzH)/sub 2/(NO/sub 3/)/sub 2/)NO/sub 3/.H/sub 2/O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole) are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm/sup -1/cm/sup 2/mol/sup -1/) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the positive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C/sub 2/v) and uncoordinated (D/sub 3/h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms.

Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

International Nuclear Information System (INIS)

Mishra, A.; Singh, M.P.; Singh, V.K.

1982-01-01

The nitrato-complexes, [Y(PyBzH) 2 (NO 3 ) 2 ]NO 3 .H 2 O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole] are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm -1 cm 2 mol -1 ) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the terpositive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C 2 v) and uncoordinated (D 3 h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms. (author)

Ortho-vanadates K3RE(VO4)2 (RE = La, Pr, Eu, Gd, Dy, Y) for near UV-converted phosphors

International Nuclear Information System (INIS)

Qin, Lin; Wei, Dong-Lei; Huang, Yanlin; Qin, Chuanxiang; Cai, Peiqing; Kim, Sun-Il; Seo, Hyo-Jin

2014-01-01

The orthovanadate poly-crystals K 3 RE(VO 4 ) 2 (RE = La, Pr, Eu, Gd, Dy, Y) were synthesized via the solid-state reaction route. The crystal phase formation was verified through X-ray diffraction (XRD) studies and was performed by structural refinements. The optical properties were also investigated in detail. K 3 RE(VO 4 ) 2 (RE = Eu, Dy, Gd, Pr, La, Y) phosphors present different luminescence behaviors: the profiles of excitation and emission spectra, the spectra shift, the luminescence decay lifetimes, the absolute quantum efficiency (QE), and the CIE color coordinates are very different. The luminescence of K 3 RE(VO 4 ) 2 (RE = La, Gd, Y, Pr) presents yellow or yellowish green color, while, K 3 Dy(VO 4 ) 2 and K 3 Eu(VO 4 ) 2 show white and red luminescence, respectively. This was discussed on the base of the different micro-structure, activator centers, and the charge transfer transitions from [VO 4 ] 3− groups in the lattices. K 3 Y(VO 4 ) 2 and K 3 Eu(VO 4 ) 2 show higher QE values of 47.0% and 45.0% at room temperature, respectively. All the phosphors have efficient absorption in the region of near-UV wavelengths or blue wavelength region. This can well match with the light from UV-LED (360–400 nm) or blue LED chips (450–480 nm) based on GaN semiconductor. K 3 RE(VO 4 ) 2 could be suggested to be a potential candidate to give further investigations for the application on near-UV excited white LEDs. - Graphical abstract: A series of orthovanadates K 3 RE(VO 4 ) 2 (RE = Eu, Dy, Gd, Pr, La, Y) have been developed to be new phosphors with rich luminescence colors; there are efficiency excitation in the near UV wavelength region. Compared with the reported vanadate phosphors K 3 R(VO 4 ) 2 has rich luminescence color, rich color, no concentration quenching, and comparable luminescence QE. - Highlights: • A new phosphor of non-doped of K 3 R(VO 4 ) 2 (R = Eu, Dy, Gd, Pr, La, Y) were developed by solid-state reaction route. • The phosphor

Subsolidus Phase Relations of the CaO-REOx-CuO Systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) at 900 °C in Air

DEFF Research Database (Denmark)

Grivel, Jean-Claude

2016-01-01

The subsolidus phase relations of the CaO-REOx-CuO systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) were investigated in air at 900 °C. The pseudo-ternary sections with RE = Tb, Dy, Ho, Er and Lu have a similar structure. They have in common with the RE = Eu system a solid solution of Ca0.833−xRExCuO2......+y composition but the system with RE = Eu differs by the presence of an Eu2CuO4 phase instead of RE2Cu2O5 for RE = Tb, Dy, Ho, Er and Lu. In contrast, the CaO-ScO1.5-CuO section does not contain a Ca0.833−xScxCuO2+y solid solution and is dominated by the CaSc2O4 phase, which has no equivalent...... in the other systems at 900 °C in air....

Lattice mismatch and energy transfer of Eu- and Dy-codoped MO–Al2O3–SrO (M=Mg, Ca, Ba) ternary compounds affecting luminescence behavior

International Nuclear Information System (INIS)

Liang, Chen-Jui; Huang, Kuan-Yu

2017-01-01

A systematic investigation of energy transfers and luminescence behaviors for M x Sr 0.94−x Al 2 O 4 :Eu 0.02 , Dy 0.04 (M=Mg, Ca, Ba; x=0, 0.235, 0.47, 0.705, 0.94) ternary compounds was accomplished. The results demonstrated that six phenomena must be fitted into the energy-transfer mechanisms of the ternary compounds: (1) the optical band-gap energy of Mg 0.94 Al 2 O 4 :Eu 0.02 Dy 0.04 is extremely low and does not allow photoemission; (2) Ca 2+ and Ba 2+ ions are the main hosts when x≥0.47 in Ca x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 and Ba x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 , respectively; (3) Eu 3+ ions are the main activator ions in Ca x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 with x=0.47 and in Ba x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 with x=0.353−0.705; (4) Sr 2+ and Eu 2+ ions are the main host and activator ions, respectively, when x<0.353 in each ternary compound; (5) energy transfers from the MO phases to the SrO phase because the conduction band energy of SrO is the lowest; and (6) mutual substitution between alkaline-earth ions does not alter the resultant structures’ crystal field and nephelauxetic effects, as determined by measuring their luminescence. Two energy transfer paths were discovered to be possible in CaO–Al 2 O 3 –SrO and BaO–Al 2 O 3 –SrO ternary compounds, and the boundaries determining which path was chosen were the atomic ratios Ca:Sr and Ba:Sr, both approximately 1.6:1 (x=0.353). Because second path increased the energy transferred from the MO band gap to the SrO band gap, the corresponding structure's spectrum emission intensity was approximately 4.3 times higher than that of the SrO−Al 2 O 3 binary compound, and their photoluminescence was thus substantially higher.

Warm white light generation from single phase Sr3Y(PO4)3:Dy3+, Eu3+ phosphors with near ultraviolet excitation

International Nuclear Information System (INIS)

Huang, B.Y.; Feng, B.L.; Luo, L.; Han, C.L.; He, Y.T.; Qiu, Z.R.

2016-01-01

Highlights: • Novel single phase phosphors were synthesized in an ambient air atmosphere. • A direct band gap about 4.5 eV of the host is calculated for the first time. • It is suitable for near UV chip excitation. • It emits warm white light with better CIE and lower CCT over previous reports. • The thermal quenching is similar to that of YAG:0.06Ce 3+ commercial phosphor. - Abstract: Novel Sr 3 Y(PO 4 ) 3 :Dy 3+ , Eu 3+ (SYP:Dy 3+ , Eu 3+ ) phosphors were synthesized by a standard solid-state reaction under an ambient air atmosphere and their structural and optical properties were investigated. XRD and diffuse reflectance spectra (DRS) were used to explore structural properties. The former showed that single phase phosphors were obtained and that the rare earth ions entered into the cubic host by substituting the smaller Y 3+ ions and thereby enlarging the unit cell. The DRS indicated that the host has a direct bandgap of 4.5 eV. Under 393 nm excitation, a strong and stable warm white light emission with high color purity was achieved in SY 0.92 P:0.06Dy 3+ , 0.04Eu 3+ . The energy transfer from Dy 3+ to Eu 3+ ions was investigated and the related mechanism was discussed based on the optical spectra and emission decay curves. The thermal quenching of emission is similar to that of YAG:0.06Ce 3+ . The results show the single phase phosphor is potential in warm white LED.

Thermoluminescence properties of Eu-doped and Eu/Dy-codoped Sr2 Al2 SiO7 phosphors.

Science.gov (United States)

Jadhaw, Akhilesh; Sonwane, Vivek D; Gour, Anubha S; Jha, Piyush

2017-11-01

We report the thermoluminescence properties of Sr 1.96 Al 2 SiO 7 :Eu 0.04 and Sr 1.92 Al 2 SiO 7 :Eu 0.04 Dy 0.04 phosphors. These phosphors were prepared by a high-temperature solid-state reaction method. The prepared phosphors were characterized by X-ray diffraction. A 254 nm source was used for ultraviolet (UV) irradiation and a 60 Co source was used for γ-irradiation. The effect of heating rate and UV-exposure were examined. The thermoluminescence temperature shifts to higher values with increasing heating rate and thermoluminescence intensity increases with increasing UV exposure time. The trapping parameters such as activation energy (E), order of kinetics and frequency factor (s) were calculated by peak shape method. The effect of γ- and UV-irradiation on thermoluminescence studies was also examined. Copyright © 2017 John Wiley & Sons, Ltd.

Influence of rare-earth additives (La, Sm and Dy on the microstructure and dielectric properties of doped BaTiO3 ceramics

Directory of Open Access Journals (Sweden)

Paunović Vesna

2010-01-01

Full Text Available A series of La/Mn, Sm/Mn and Dy/Mn codoped BaTiO3 samples were prepared by the conventional solid state procedure with dopant concentrations ranging from 0.1 up to 2.0 at%. The specimens were sintered at 1320°C and 1350°C in an air atmosphere for two hours. The low doped samples demonstrated a mainly uniform and homogeneous microstructure with average grain sizes ranging from 0.3 μm to 5.0 μm. The appearance of secondary abnormal grains in the fine grain matrix and core-shell structure were observed in highly doped La/BaTiO3 and Dy/BaTiO3 sintered at 1350°C. The low doped samples, sintered at 1350°C, display a high value of dielectric permittivity at room temperature, 6800 for Sm/BaTiO3, 5900 for Dy/BaTiO3 and 3100 for La/BaTiO3. A nearly flat permittivity-response was obtained in specimens with 2.0 at% additive content. Using a modified Curie-Weiss law the Curie-like constant C⁄ and a critical exponent γ were calculated. The obtained values of γ pointed out the diffuse phase transformation in heavily doped BaTiO3 samples.

Synthesis of KMgCl{sub 3} nanomaterial and luminescence of Ce{sup 3+}/Dy{sup 3+}/Eu{sup 3+} by different routes

Energy Technology Data Exchange (ETDEWEB)

Poddar, Anuradha [Department of Physics, Sindhu Mahavidyalaya, Nagpur 440017 (India); Gedam, S.C., E-mail: gedam_sc@rediffmail.com [Department of Physics, K.Z.S. Science College, Kalmeshwar, Nagpur 441501 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India)

2015-02-15

The present KMgCl{sub 3} phosphor has been synthesized through wet chemical synthesis (WCS), solid state diffusion (SSD) and Hispersed centrifuge (HC) routes in the same atmospheric conditions and characterized for luminescence properties. XRDs of the sample prepared by all three methods have been placed at the same position, phase and matched well with standard data. The particle size of 20 nm of KMgCl{sub 3} by a Hispersed centrifuged method was detected using a transmission electron microscope (TEM). The PL emission spectra have been observed for Ce{sup 3+} at 353 nm and 375 nm due to 5d→4f transition, whereas luminescence of Dy{sup 3+} efficiently observed at 484 nm and 579 nm for an excitation of 384 nm due to {sup 4}F{sub 9/2}→ {sup 6}H{sub 15/2} and {sup 6}H{sub 13/2} (blue–yellow region) transition and Eu{sup 3+} is peaking at 596 nm and 616 nm (λ{sub ex}=394 nm) due to level {sup 5}D{sub 0} to {sup 7}F{sub j} (j=0, 1, 2, and 3) radiative transitions. The presented phosphors are excited in the range of 300–400 nm which is mercury free excited range. Synthesis and photoluminescence spectra of trivalent Ce, Dy or Eu rare-earths in KMgCl{sub 3} are described for all three routes, for the first time in the present work. The CIE chromaticity coordinates were also calculated for KMgCl{sub 3}:X (Ce{sup 3+}, Dy{sup 3+} and Eu{sup 3+}) phosphors, which are close to the NTSC standard values. KMgCl{sub 3} matrix is not only suitable for different and easy synthesis but efficient luminescence also. The paper discuses the XRD, crystallinity (morphology) and luminescence of Ce, Dy or Eu rare-earths in KMgCl{sub 3} synthesized by three (WCS, SSD and HC) different routes. - Highlights: • The particle size 20 nm of KMgCl{sub 3} was detected by Hispersed centrifuged method using TEM. • The phosphors are prepared by very simple WCM, SSD and HS technique. • An efficient luminescence is observed in KMgCl{sub 3}:X (X=Ce{sup 3+}, Dy{sup 3+} and Eu{sup 3

Luminescence enhancement in Eu3+, Sm3+ co-doped liy(MoO4)2 nano-phosphors by sol-gel process.

Science.gov (United States)

Zhou, Xianju; Wang, Guangchuan; Zhou, Tonghui; Zhou, Kaining; Li, Qingxu; Wang, Zhongqing

2014-05-01

A series of LiY(0.95-x)Eu(0.05)Sm(x)(MoO4)2 red light emitting phosphors were synthesized by sol-gel technique. The phase impurity and spectroscopic properties were characterized by X-ray Diffraction (XRD), Photo-Luminescence (PL) and Photo-Luminescence Excitation (PLE) spectra, respectively. It is found that the PLE spectra of the Eu3+, Sm3+ co-doped nanoparticles are enhanced and broadened as compared with the solely doped samples, which will make the co-doped phosphors match better with blue and/or UV GaN based LED chips. The red emission intensity of Eu3+ is largely enhanced by the energy transfer from Sm3+. The mechanism of the enhancement is clearly proven to be the increase in the quantum efficiency of 5D0 state of Eu3+ rather than the increase in the absorption of Eu3+. Meanwhile, the characteristic f-f transitions of Sm3+ are greatly reduced, resulting in little influence in the color purity of the co-doped phosphors. The present material is an amendatory promising red light emitting phosphor for white LEDs.

Single-phase and warm white-light-emitting phosphors CaLa{sub 2−x−y}(MoO{sub 4}){sub 4}: xDy{sup 3+}, yEu{sup 3+}: Synthesis, luminescence and energy transfer

Energy Technology Data Exchange (ETDEWEB)

Han, Li; Liu, Guixia, E-mail: liuguixia22@163.com; Dong, Xiangting; Wang, Jinxian; Yu, Wensheng

2016-10-15

A series of single-phase warm white light emitting CaLa{sub 2−x−y}(MoO{sub 4}){sub 4}: xDy{sup 3+}, yEu{sup 3+} phosphors were synthesized by a typical sol–gel method. X-ray diffraction (XRD) analysis reveals that the crystal structures of the samples are matched well with the tetragonal CaMoO{sub 4}. Upon ultraviolet (UV) light radiation, the Dy{sup 3+} or Eu{sup 3+} ions singly activated CaLa{sub 2}(MoO{sub 4}){sub 4} phosphors exhibit corresponding emissions originated from the f–f transitions of Dy{sup 3+} or Eu{sup 3+} ions. Under near ultraviolet (n-UV) light excitation, in the Dy{sup 3+} and Eu{sup 3+} ions co-doped samples, the energy transfer (ET) phenomenon from Dy{sup 3+} to Eu{sup 3+} ions can be observed and has been demonstrated to be a quadrupole–quadrupole interaction mechanism. The emission color of CaLa{sub 1.98−y}(MoO{sub 4}){sub 4}: 0.02Dy{sup 3+}, yEu{sup 3+} samples can be tuned from cool to warm white light by adjusting the concentration of Eu{sup 3+} ions. In addition, it can be found that CaLa{sub 1.974}(MoO{sub 4}){sub 4}: 0.02Dy{sup 3+}, 0.006Eu{sup 3+} samples emit bright white light with the CIE coordinate of (0.348, 0.313) and the color temperature of 5087 K, which is very close to the standard white light. All the results demonstrate that the as-synthesized phosphors have great potential applications in the field of n-UV white light emitting diodes (WLEDs).

Preparation and luminescence properties of Ca3(VO4)2: Eu3+, Sm3+ phosphor for light-emitting diodes

International Nuclear Information System (INIS)

Huang Jiaping; Li Qiuxia; Chen Donghua

2010-01-01

Rare-earth ions co-activated red phosphors Ca 3 (VO 4 ) 2 : Eu 3+ , Sm 3+ were synthesized by modified solid-state reactions. The samples were characterized by X-ray powder diffractometer (XRD), energy-dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and luminescence spectrometer (LS). The results showed that the Eu-Sm system exhibits higher emission intensity than those of the Eu single-doped system and Sm separate-doped system under blue light. Samarium (III) ions are effective in broadening and strengthening absorptions around 467 nm. Furthermore, they exhibit enhanced luminescence emission. Luminescent measurements showed that the phosphors can be efficiently excited by ultraviolet (UV) to visible region, emitting a red light with a peak wavelength of 616 nm. The material has potential application as a phosphor for light-emitting diodes (LEDs).

Preparation, structural characterization, and enhanced electrical conductivity of pyrochlore-type (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics

Energy Technology Data Exchange (ETDEWEB)

Xia, X.L. [Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin (China); Institute of Oceanography Instruments, Shandong Academy of Science, Chinese National Engineering Research Center for Marine Monitoring Equipment, Qingdao (China); Liu, Z.G.; Ouyang, J.H. [Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin (China); Zheng, Y. [Institute of Oceanography Instruments, Shandong Academy of Science, Chinese National Engineering Research Center for Marine Monitoring Equipment, Qingdao (China)

2012-08-15

(Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} (0 {<=} x {<=} 1.0) samples are prepared by solid state reaction method using Sm{sub 2}O{sub 3}, Eu{sub 2}O{sub 3}, and ZrO{sub 2} as starting materials. The phase composition and microstructure of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics are investigated by X-ray diffraction (XRD), scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM) coupled with selected area electron diffraction and Raman spectroscopy. XRD and TEM show that all the samples exhibit a single pyrochlore-type structure. HRTEM observation indicates that the whole grain interior of Sm{sub 2}Zr{sub 2}O{sub 7} ceramic is a perfect crystal free of any dislocation. Raman spectroscopy reveals that the degree of structural disorder of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics increases gradually with increasing Eu content. The electrical conductivity of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics is investigated by impedance spectroscopy in the air and hydrogen atmospheres, respectively. The electrical conductivity of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics increases with increasing Eu content at identical temperature levels. Both the activation energy E{sub g} and the pre-exponential factor {sigma}{sub 0g} for the grain conductivity gradually increase with increasing Eu content. As the ionic conductivity shows no obvious change in both air and hydrogen atmospheres, the conduction of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} is purely ionic with negligible electronic conduction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Persistent luminescence, TL and OSL characterization of beta irradiated SrAl2O4:Eu2+, Dy3+ combustion synthesized phosphor

International Nuclear Information System (INIS)

Zúñiga-Rivera, N.J.; García, R.; Rodríguez-Mijangos, R.; Chernov, V.; Meléndrez, R.; Pedroza-Montero, M.; Barboza-Flores, M.

2014-01-01

The persistent luminescence (PLUM), thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of strontium aluminates co-doped with Eu +2 and Dy +3 exposed to beta radiation is reported. The phosphor was synthesized by the combustion synthesis method employing a highly exothermic redox reaction between the metal nitrates [Al(NO 3 ) 3 , Sr(NO 3 ) 2 , Eu(NO 3 ) 3 and Dy(NO 3 ) 3 ] and organic fuel carbohydrazide (CH 6 N 4 O). The long decay PLUM emission, TL and OSL were measured as a function of beta radiation dose. A wide emission band centered at 510 nm (green) related to Eu 2+ ions and lattice defects were observed for the synthesized samples. The presence of a variety of defects and aggregates were responsible for the observed broad 100 °C peaked TL glow curve of the irradiated sample which is composed of several overlapped TL peaks. The existence of multiple trapping levels, with different trapping/detrapping probabilities, is behind the particular features for the PLUM, TL and OSL emissions. We conclude that in the SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors, the low temperature TL peaked around 30–75 °C is responsible for the PLUM emission and those around 100 °C were related to very stable trapping states which provide suitable radiation storage properties to be used as a PLUM/TL/OSL radiation phosphor

The study of structural and optical properties of (Eu, La, Sm) codoped ZnO nanoparticles via a chemical route

Energy Technology Data Exchange (ETDEWEB)

Lang, Jihui; Zhang, Qi; Han, Qiang; Fang, Yue; Wang, Jiaying; Li, Xiuyan; Liu, Yanqing [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping, 136000 (China); Wang, Dandan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); Yang, Jinghai, E-mail: jhyang1@jlnu.edu.cn [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping, 136000 (China); Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)

2017-06-15

The (Eu, La, Sm) ions were doped into ZnO nanoparticles by a chemical route, and the substitution of (Eu, La, Sm) for Zn{sup 2+} ions was proved by analytic techniques of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, transmission electron microscope (TEM), photoluminescence (PL) and UV–vis absorption spectroscopy. The results revealed that the codoping did not change the wurtzite structure of ZnO nanoparticles, but the diameter of the nanoparticles decreased with increasing the rare earth (RE) doping concentrations. The optical bandgaps calculated through UV–visible absorption spectroscopy were found to decrease from 3.26 to 3.14 eV with increasing the RE doping concentrations, which also proved by the slight shift of UV positions in PL spectra. The sharp red emissions located at 578.2, 590.1 and 615.7 nm were originated from the 4f-4f transitions in Eu{sup 3+} ions under excitation of 325 nm. And these red emissions of Eu{sup 3+} ions showed a strong correlation with the energy storage centers of oxygen vacancies in the samples which was introduced by the other RE ions of La{sup 3+} and Sm{sup 3+} codoping. - Highlights: • Doping of (Eu, La, Sm) ions into ZnO nanoparticles is realized by a chemical route. • Eu{sup 3+}-related red emissions from intra-4f follow a similar trend as broad defect emission. • Red emissions of Eu{sup 3+} enhance with RE codoping due to oxygen vacancies as energy storage centers. • The bandgap can be tuned by RE codoping, which shows a prospect for the visible utilization.

Formation constants of Sm(III), Dy(III), Gd(III), Pr(III) and Nd(III) complexes of tridentate schiff base, 2-[(1H-benzimidazol-2-yl-methylene) amino] phenol

International Nuclear Information System (INIS)

Omprakash, K.L.; Chandra Pal, A.V.; Reddy, M.L.N.

1982-01-01

A new tridentate schiff base, 2- (1H-benzimidazol-2-yl-methylene)amino phenol derived from benzimididazole-2-carbo-xaldehyde and 2-aminophenol has been synthesised and characterised by spectral and analytical data. Proton-ligand formation constants of the schiff base and metal-ligand formation constants of its complexes with Sm(III), Dy(III), Gd(III), Nd(III) and Pr(III) have been determined potentiometrically in 50% (v/v) aqueous dioxane at an ionic strength of 0.1M (NaClO 4 ) and at 25deg C using the Irving-Rossotti titration technique. The order of stability constants (logβ 2 ) is found to be Sm(III)>Dy(III)>Gd(III)>Pr(III)>Nd(III). (author)

Formation constants of Sm(III), Dy(III), Gd(III), Pr(III) and Nd(III) complexes of tridentate schiff base, 2-((1H-benzimidazol-2-yl-methylene) amino) phenol

Energy Technology Data Exchange (ETDEWEB)

Omprakash, K L; Chandra Pal, A V; Reddy, M L.N. [Osmania Univ., Hyderabad (India). Dept. of Chemistry

1982-03-01

A new tridentate schiff base, 2- (1H-benzimidazol-2-yl-methylene)amino phenol derived from benzimididazole-2-carbo-xaldehyde and 2-aminophenol has been synthesised and characterised by spectral and analytical data. Proton-ligand formation constants of the schiff base and metal-ligand formation constants of its complexes with Sm(III), Dy(III), Gd(III), Nd(III) and Pr(III) have been determined potentiometrically in 50% (v/v) aqueous dioxane at an ionic strength of 0.1M (NaClO/sub 4/) and at 25deg C using the Irving-Rossotti titration technique. The order of stability constants (log..beta../sub 2/) is found to be Sm(III)>Dy(III)>Gd(III)>Pr(III)>Nd(III).

A first-principles study of B2 NiAl alloyed with rare earth elements Pr, Pm, Sm, and Eu

Institute of Scientific and Technical Information of China (English)

He Jun-Qi; Wang You; Yan Mu-Fu; Pan Zhao-Yi; Guo Li-Xin

2013-01-01

The structural,elastic,and electronic properties of NiAl alloyed with rare earth elements Pr,Pm,Sm,and Eu are investigated by using density functional theory (DFT).The study suggests that Pr,Pm,Sm,and Eu all tend to be substituted for an Al site.Ni8Al7Pm possesses the largest ductility.Only the hardness and ductility of Ni8Al7Eu are enhanced simultaneously.The covalency strength of the Ni-Al bond in Ni8Al7Pm is higher than that in Ni8Al7Eu.The covalency strength of an Al-Al bond and that of a Ni-Ni bond in Ni8Al7Eu are higher than that in Ni8Al7Pm.The Ni-Pm bond and the Ni-Eu bond are covalent,and the covalency strength of the Ni-Pm bond is greater.The Al-Pm bond and the Al-Eu bond show great covalency strength and ionicity,respectively.

High-pressure behavior of A ₂ B ₂ O ₇ pyrochlore (A=Eu, Dy; B=Ti, Zr)

Energy Technology Data Exchange (ETDEWEB)

Rittman, Dylan R.; Turner, Katlyn M.; Park, Sulgiye; Fuentes, Antonio F.; Yan, Jinyuan; Ewing, Rodney C.; Mao, Wendy L.

2017-01-28

In situ high-pressure X-ray diffraction and Raman spectroscopy were used to determine the influence of composition on the high-pressure behavior of A₂B₂O₇ pyrochlore (A=Eu, Dy; B=Ti, Zr) up to ~50GPa. Based on X-ray diffraction results, all compositions transformed to the high-pressure cotunnite structure. The B-site cation species had a larger effect on the transition pressure than the A-site cation species, with the onset of the phase transformation occurring at ~41 GPa for B=Ti and ~16 GPa B=Zr. However, the A-site cation affected the kinetics of the phase transformation, with the transformation for compositions with the smaller ionic radii, i.e., A=Dy, proceeding faster than those with a larger ionic radii, i.e., A=Eu. These results were consistent with previous work in which the radius-ratio of the A- and B-site cations determined the energetics of disordering, and compositions with more similarly sized A- and B-site cations had a lower defect formation energy. Raman spectra revealed differences in the degree of short-range order of the different compositions. Due to the large phase fraction of cotunnite at high pressure for B=Zr compositions, Raman modes for cotunnite could be observed, with more modes recorded for A=Eu than A=Dy. These additional modes are attributed to increased short-to-medium range ordering in the initially pyrochlore structured Eu₂Zr₂O₇ as compared with the initially defect-fluorite structured Dy₂Zr₂O₇.

Synthesis and photoluminescence characteristics of (Y,Gd)BO3:RE (RE = Eu(3+), Ce(3+), Dy(3+) and Tb(3+)) phosphors for blue chip and near-UV white LEDs.

Science.gov (United States)

Rangari, V V; Singh, V; Dhoble, S J

2016-03-01

A series of Eu(3+)-, Ce(3+)-, Dy(3+)- and Tb(3+)-doped (Y,Gd)BO3 phosphors was synthesized by a solid-state diffusion method. X-Ray diffraction confirmed their hexagonal structure and the scanning electron microscopy results showed crystalline particles. The excitation spectra revealed that (Y,Gd)BO3 phosphors doped with Eu(3+), Ce(3+), Dy(3+) and Tb(3+) are effectively excited with near UV-light of 395 nm/blue light, 364, 351 and 314 nm, respectively. Photoluminescence spectra of Eu(3+)-, Ce(3+)- and Tb(3+)/Dy(3+)-doped phosphor showed intense emission of reddish orange, blue and white light, respectively. The phosphor Y0.60Gd0.38BO3:Ce0.02 showed CIE 1931 color coordinates of (0.158, 0.031) and better color purity compared with commercially available blue BAM:Eu(2+) phosphor. The phosphor (Y,Gd)BO3 doped with Eu(3+), Dy(3+) and Tb(3+) showed CIE 1931 color coordinates of (0.667, 0.332), (0.251, 0.299) and (0.333, 0.391) respectively. Significant photoluminescence characteristics of the prepared phosphors indicate that they might serve as potential candidates for blue chip and near-UV white light-emitting diode applications. Copyright © 2015 John Wiley & Sons, Ltd.

Phosphorescent and thermoluminescent properties of SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} phosphors prepared by solid state reaction method

Energy Technology Data Exchange (ETDEWEB)

Mothudi, B.M., E-mail: mothubm@unisa.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Department of Physics, University of South Africa, P.O. Box 392, Pretoria, ZA 6031 (South Africa); Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Kumar, A.; Sohn, K. [Department of Material Science and Metallurgical Engineering, Sunchon National University, Sunchon, Chonam 540-742 (Korea, Republic of); Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa)

2012-05-15

Long persistent SrAl{sub 2}O{sub 4}:Eu{sup 2+} phosphors co-doped with Dy{sup 3+} were prepared by the solid state reaction method. The main diffraction peaks of the monoclinic structure of SrAl{sub 2}O{sub 4} were observed in all the samples. The broad band emission spectra at 497 nm for SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} were observed and the emission is attributed to the 4f{sup 6}5d{sup 1} to 4f{sup 7} transition of Eu{sup 2+} ions. The samples annealed at 1100-1200 Degree-Sign C showed similar broad TL glow curves centered at 120 Degree-Sign C. The similar TL glow curves suggest that the traps responsible for them are similar. The long afterglow displayed by the phosphors annealed at different temperatures, may be attributed to the Dy{sup 3+} ions acting as the hole trap levels, which play an important role in prolonging the duration of luminescence.

The behavior of thermally and optically stimulated luminescence of SrAl2O4:Eu2+,Dy3+ long persistent phosphor after blue light illumination

International Nuclear Information System (INIS)

Chernov, V.; Melendrez, R.; Pedroza-Montero, M.; Yen, W.M.; Barboza-Flores, M.

2008-01-01

The behavior of afterglow (AG), thermoluminescence (TL), infrared stimulated luminescence (IRSL) and phototransferred TL (PTTL) under thermal and/or infrared (IR) stimulation in blue (470 nm) light illuminated at room temperature (RT) SrAl 2 O 4 :Eu 2+ , Dy 3+ is presented. The TL glow curve consists of four peaks with maxima at about 340, 430, 560 and 680 K. The 340 and 440 K peaks are described well by second order kinetics with activation energies of 0.83 and 1.05 eV, respectively. The AG decay is fitted by the Becquerel's law with exponent 1.5 and correlates well with the thermal emptying of the traps responsible for the 340 K peak. The 340 and 430 K TL peak traps are destroyed under IR (830 nm) stimulation creating IRSL. IR stimulation after illumination with blue light and preliminary heating restore partially the 340 and 430 K TL peaks by phototransfer from deeper traps. The shape of the IRSL decay curves depends strongly on the preheating temperature and is determined by simultaneous refilling of the 340 and 430 K TL traps and their reverse filling due to phototransfer from the deeper traps under IR stimulation. The obtained data are interpreted by the transformation of Eu 2+ and Dy 3+ to Eu 3+ and Dy 2+ under blue light illumination and their reverse transformation under thermal or IR stimulation. The Eu 2+ ions are the luminescent centers and the Dy 2+ centers are the IR sensitive traps responsible for the TL peaks, AG and IRSL

Synthesis of three-dimensional flower-like BiOCl:RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}) globular microarchitectures and their luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Guo, Yang-Yang; Zhang, Zhi-Jun [Department of Physics, Dongguk University, Seoul, 100715 (Korea, Republic of); Zhu, Gang-Qiang [Department of Physics, Shanxi Normal University, Xi’an, 710062 (China); Yang, Woochul, E-mail: wyang@dongguk.edu [Department of Physics, Dongguk University, Seoul, 100715 (Korea, Republic of)

2016-12-01

Graphical abstract: - Highlights: • Three-dimensional flower-like Eu{sup 3+} and Sm{sup 3+}-activated BiOCl globular microarchitectures have been synthesized. • Ostwald ripening and recrystallization are responsible for the growth mechanism of BiOCl microarchitectures. • Efficient red-emission from Eu{sup 3+}:BiOCl is observed due to the well-crystallized structures of the microarchitectures. - Abstract: Three-dimensional flower-like Eu{sup 3+} and Sm{sup 3+}-activated BiOCl globular microarchitectures were synthesized by the solvothermal method employing urea as a dispersing agent for the first time. The crystal structure, morphologies and luminescence properties of Eu{sup 3+} and Sm{sup 3+} doped BiOCl have been systematically investigated by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) and spectroscopy, respectively. The unit cell volumes show a nearly linear decrease by about 0.18 and 0.15% with increasing Eu{sup 3+} and Sm{sup 3+} concentration up to 9 mol%, respectively. All of the prepared samples show flower-like globular microarchitectures with an average diameter about 3–5 μm with different Eu{sup 3+} and Sm{sup 3+} concentrations. Possible formation mechanism for the flower-like microarchitectures is proposed on the basis of time-dependent experiment. Both BiOCl:Eu{sup 3+} and BiOCl:Sm{sup 3+} samples show a strong red emission corresponding to the {sup 5}D{sub 0} → {sup 7}F{sub 4} transition (700 nm) of Eu{sup 3+} and {sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition (600 nm) of Sm{sup 3+}, respectively. This work sheds some light on the design and preparation of red-emitting phosphors with novel microstructures.

Thermoelectric properties, crystal and electronic structure of semiconducting RECuSe2 (RE = Pr, Sm, Gd, Dy and Er)

International Nuclear Information System (INIS)

Esmaeili, Mehdi; Tseng, Yu-Chih; Mozharivskyj, Yurij

2014-01-01

Highlights: • Crystal and electronic structure of monoclinic and trigonal RECuSe 2 phases. • Thermoelectric properties of the RECuSe 2 phases. • Temperature stability of the RECuSe 2 phases. - Abstract: The ternary RECuSe 2 phases have been prepared and structurally characterized. They adopt either a monoclinic structure (P2 1 /c, z = 4) for lighter rare earths (RE = Pr, Sm and Gd) or Cu-disordered trigonal structure for heavier rare-earths (P3 ¯ m1, z = 1, RE = Dy and Er). The resistivity and Seebeck coefficient measurements on GdCuSe 2 , DyCuSe 2 and ErCuSe 2 indicate that the studied phases are p-type semiconductors with relatively small activation energies (0.045–0.11 eV). However, their electrical resistivities are too high (0.45–220 Ω cm at room temperature) to make them competitive thermoelectric materials. Electronic structure calculations indicate presence of a band gap in the RECuSe 2 phases

Photoluminescence and phosphorescence properties of MAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} (M=Ca, Ba, Sr) phosphors prepared at an initiating combustion temperature of 500 deg. C

Energy Technology Data Exchange (ETDEWEB)

Mothudi, B.M., E-mail: mothudibm@qwa.uovs.ac.z [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth, ZA 6031 (South Africa); Swart, H.C., E-mail: swarthc.sci@ufs.ac.z [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa)

2009-12-01

Eu{sup 2+} and Dy{sup 3+} co-doped calcium aluminate, barium aluminate and strontium aluminate phosphors were synthesized at an initiating combustion temperature of 500 deg. C using urea as an organic fuel. The crystallinity of the phosphors was investigated by using X-ray diffraction (XRD) and the morphology was determined by a scanning electron microscope (SEM). The low temperature monoclinic structure for both CaAl{sub 2}O{sub 4} and SrAl{sub 2}O{sub 4} and the hexagonal structure of BaAl{sub 2}O{sub 4} were observed. The effect of the host materials on the photoluminescence (PL) and phosphorescence properties were investigated by using a He-Cd Laser and a Cary Eclipse fluorescence spectrophotometer, respectively. The broad band emission spectra observed at 449 nm for CaAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+}, 450 nm (with a shoulder-peak at 500 nm) for BaAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} and 528 nm for SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} are attributed to the 4f{sup 6}5d{sup 1} to 4f{sup 7} transition in the Eu{sup 2+} ion in the different hosts.

L-shell X-ray production cross sections of Ce, Nd, Sm, Eu, Gd, and Dy by impact of {sup 14}N{sup 2+} ions with energies between 7.0 MeV and 10.5 MeV

Energy Technology Data Exchange (ETDEWEB)

Murillo, G.; Méndez, B.; López-Monroy, J. [Departamento de Aceleradores, Instituto Nacional de Investigaciones Nucleares, Carr. México-Toluca S/N, Ocoyoacac, Edo. Méx. 52750 (Mexico); Miranda, J., E-mail: miranda@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, A.P. 20-364, México, Cd. Mx. 01000 (Mexico); Villaseñor, P. [Departamento de Aceleradores, Instituto Nacional de Investigaciones Nucleares, Carr. México-Toluca S/N, Ocoyoacac, Edo. Méx. 52750 (Mexico)

2016-09-15

Highlights: • A new data set of L X-ray production cross sections by nitrogen ion impact is given. • The target elements have atomic numbers in the range 58–66 (lanthanoids). • A universal scaling as function of a reduced velocity variable is applied. • The eCPSSR model with EC and MI corrections gives very good results. - Abstract: L-shell X-ray production cross sections from the lanthanoid elements Ce, Nd, Sm, Eu, Gd, and Dy, induced by the impact of {sup 14}N{sup 2+} ions with energies in the interval 7.0 MeV to 10.5 MeV (0.50 MeV/μ to 0.75 MeV/μ), were measured and then compared with theoretical calculations obtained with the ECPSSR model with exact limits of integration (eCPSSR) and related corrections. These include the electron capture by the incoming ion and multiple ionizations of higher shells. Data from this work were contrasted with previously published L X-ray production cross sections for {sup 14}N{sup 2+} ion impact. As with other ions, a universal behavior is found when L{sub α} and L{sub γ} X-ray production cross sections are plotted as a function of reduced velocity parameters. The agreement with theoretical predictions was very good when the corrections were applied to the eCPSSR model.

Structural and luminescent study of TeO2-BaO-Bi2O3-Ag glass system doped with Eu3+ and Dy3+ for possible color-tunable phosphor application

Science.gov (United States)

Lewandowski, Tomasz; Seweryński, Cezary; Walas, Michalina; Łapiński, Marcin; Synak, Anna; Sadowski, Wojciech; Kościelska, Barbara

2018-05-01

Tellurite glass systems of 73TeO2-4BaO-3Bi2O3-1Ag:xEu2O3-(2-x)Dy2O3 (where x = 0.5, 1, 1.5, 2 in molar ratio) composition have been successfully synthesized. In order to acquire Ag nanoparticles, materials have been heat treated at 350 °C in the air atmosphere. Structural properties of obtained samples were evaluated with various techniques. X-Ray Diffraction (XRD) measurements indicated that obtained materials are amorphous in nature. UV-vis results presented transitions characteristic to Dy3+ and Eu3+ ions. Additionally, X-Ray Photoelectron Spectroscopy (XPS) analysis indicated the presence of silver in metallic form. Photoluminescence measurements shown influence of Ag nanoparticles on emission characteristics. Simultaneous emission of Dy3+ and Eu3+ has been observed when samples were excited with λexc = 390 nm. Change of the emission color induced by heat treatment has been observed and described in case of x = 1 glass series. According to CIE results emission color changes as Eu/Dy ratio and heat treatment time are changed. Emission shifts from reddish-orange to yellowish white color. Obtained photoluminescence results confirm that synthesized materials are good candidates for color tunable phosphors.

Rapid formation of red long afterglow phosphor Sr3Al2O6:Eu2+, Dy3+ by microwave irradiation

International Nuclear Information System (INIS)

Zhang Ping; Xu Mingxia; Zheng Zhentai; Sun Bo; Zhang Yanhui

2007-01-01

A new red long afterglow phosphor Sr 3 Al 2 O 6 :Eu 2+ , Dy 3+ nanocrystalline particles were prepared using a microwave oven operated at a frequency of 2.45 GHz and a power of 680 W in a weak reductive atmosphere. The phosphor nanocrystalline particles were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The results reveal that the samples are composed of single Sr 3 Al 2 O 6 phase. The obtained nanocrystalline particles show small size (80-100 nm) and spherical shape. The excitation and emission spectra indicate that excitation broadband chiefly lies in visible range and the nanocrystalline particles emit strong light at 612 nm under around 473 nm excitation. The effect of Eu 2+ doping concentrations of the samples on the emission intensity is studied systematically. Furthermore, comparing with conventional heating method, the microwave method has the advantages such as short heating time and low energy consumption. However, the decay speed of the afterglow for Sr 3 Al 2 O 6 :Eu 2+ , Dy 3+ nanocrystalline particles is faster than that obtained by the conventional heating method

Lattice mismatch and energy transfer of Eu- and Dy-codoped MO–Al{sub 2}O{sub 3}–SrO (M=Mg, Ca, Ba) ternary compounds affecting luminescence behavior

Energy Technology Data Exchange (ETDEWEB)

Liang, Chen-Jui, E-mail: cjliang@fcu.edu.tw; Huang, Kuan-Yu

2017-05-15

A systematic investigation of energy transfers and luminescence behaviors for M{sub x}Sr{sub 0.94−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}, Dy{sub 0.04} (M=Mg, Ca, Ba; x=0, 0.235, 0.47, 0.705, 0.94) ternary compounds was accomplished. The results demonstrated that six phenomena must be fitted into the energy-transfer mechanisms of the ternary compounds: (1) the optical band-gap energy of Mg{sub 0.94}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} is extremely low and does not allow photoemission; (2) Ca{sup 2+} and Ba{sup 2+} ions are the main hosts when x≥0.47 in Ca{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} and Ba{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04}, respectively; (3) Eu{sup 3+} ions are the main activator ions in Ca{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} with x=0.47 and in Ba{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} with x=0.353−0.705; (4) Sr{sup 2+} and Eu{sup 2+} ions are the main host and activator ions, respectively, when x<0.353 in each ternary compound; (5) energy transfers from the MO phases to the SrO phase because the conduction band energy of SrO is the lowest; and (6) mutual substitution between alkaline-earth ions does not alter the resultant structures’ crystal field and nephelauxetic effects, as determined by measuring their luminescence. Two energy transfer paths were discovered to be possible in CaO–Al{sub 2}O{sub 3}–SrO and BaO–Al{sub 2}O{sub 3}–SrO ternary compounds, and the boundaries determining which path was chosen were the atomic ratios Ca:Sr and Ba:Sr, both approximately 1.6:1 (x=0.353). Because second path increased the energy transferred from the MO band gap to the SrO band gap, the corresponding structure's spectrum emission intensity was approximately 4.3 times higher than that of the SrO−Al{sub 2}O{sub 3} binary compound, and their photoluminescence was thus substantially higher.

Luminescence studies of Sm(III) and Cm(III) complexes in NaSCN/DHDECMP extraction systems

CERN Document Server

Chung, D Y; Kimura, T

1999-01-01

Laser-induced fluorescence (LIF) studies of Sm(III) and Cm(III) complexes in the NaSCN/DHDECMP solvent extraction system were carried out. Luminescence lifetimes were measured to determine the number of water molecules coordinated to Sm(III), Tb(III), Dy(III), and Cm(III) in the sodium thiocyanate solution and in the DHDECMP phase. The hydration number of Sm(III), Tb(III), Dy(III), and Cm(III) in the sodium thiocyanate solution decreased linearly with increasing sodium thiocyanate concentration. The hydration numbers of Sm(III), Dy(III), and Cm(III) in the DHDECMP phase decreased with increasing sodium thiocyanate concentration. The water molecules in the inner coordination sphere of Sm(III) and Dy(III) extracted into the DHDECMP were not completely removed at low sodium thiocyanate concentration but decreased with increasing sodium thiocyanate concentration. However, in the case of Cm(III) extracted into the DHDECMP phase from the sodium thiocyanate solution, there was no water in the inner coordination sphe...

Integral-capture measurements and cross-section adjustments for Nd, Sm, and Eu

International Nuclear Information System (INIS)

Anderl, R.A.; Schmittroth, F.; Harker, Y.D.

1981-07-01

Integral-capture reaction rates are reported for 143 Nd, 144 Nd, 145 Nd, 147 Sm, 151 Eu, 152 Eu, 153 Eu, and 154 Eu irradiated in different neutron spectra in EBR-II. These reaction rates are based primarily on mass-spectrometric measurements of the isotopic atom ratios of the capture product to the target nuclide. The neutron spectra are characterized using passive neutron dosimetry and spectrum-unfolding with the FERRET least-squares data analysis code. Reaction rates for the neutron spectrum monitors were determined by the radiometric technique using Ge(Li) spectrometers. These rates are also reported here. The integral data for the rare-earth samples and for the spectrum monitors were used in multigroup flux/cross-section adtustment analyses with FERRET to generate adjustments to 47 group representations of the ENDF/B-IV capture cross sections for the rare-earth isotopes. These adjusted cross sections are in good agreement with recent differential data and with adjusted cross sections based on STEK integral data. Examples are given of the use of the adjusted cross sections and covariance matrices for cross-section evaluation

EFFECT OF ALKALINE IONS ON THE PHASE EVOLUTION, PHOTOLUMINESCENCE, AND AFTERGLOW PROPERTIES OF SrAl2O4: Eu2+, Dy3+ PHOSPHOR

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HYUNHO SHIN

2012-12-01

Full Text Available A series of SrAl2O4: Eu2+, Dy3+ long-afterglow (LAG phosphors with varying concentration of Li+, Na+ and K+, has been synthesized. The increased concentration of the three types of alkaline ions does not decrease the quantity of the total luminescent phases (SrAl2O4 plus Sr4Al14O25, but a different set of secondary phases has been evoluted for the K+-added series due to the failure of the incorporation of relatively large K+ (1.38 Å to the Sr2+ (1.18 Å site in the hosts, unlike the cases of smaller Li+ (0.76 Å and Na+ (1.02 Å ions. PL excitation, PL emission, and LAG luminescence, are decreased by all investigated alkaline ions, which would be due to the diminished incorporation of Eu2+ and Dy3+ activators into the luminescent hosts by the alkaline ions. For the cases of the Li+ and Na+-added series, the incorporated Li+ or Na+ to the luminescent hosts would also limit the activation of Eu2+ and charge trapping/detrapping of Dy3+ to yield the diminished PL properties and LAG luminescence. The type of defect complex formed by the addition of Li+ and Na+ ions has been deduced and compared with that formed when no alkaline ion is added.

Crossrelaxations and non-radiative energy transfer from ({sup 4}G{sub 5/2}) Sm{sup 3+} → ({sup 5}D{sub 0}) Eu{sup 3+}: B{sub 2}O{sub 3}–ZnO glasses

Energy Technology Data Exchange (ETDEWEB)

Naresh, V., E-mail: varna.naresh@gmail.com; Rudramadevi, B.H.; Buddhudu, S., E-mail: profsb_svuniv@hotmail.com

2015-05-25

Graphical abstract: The energy transfer process occurring from Sm{sup 3+} to Eu{sup 3+} in B{sub 2}O{sub 3}–ZnO (BZn) glasses is analyzed. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm{sup 3+} and Eu{sup 3+} has been demonstrated from the spectral overlap of Eu{sup 3+} absorption and Sm{sup 3+} emission, photoluminescence spectra, energy level diagram and lifetime measurements. The energy transfer mechanism in (Sm{sup 3+} + Eu{sup 3+}) co-doped glass is governed by dipole–dipole interaction. - Highlights: • Spectroscopic properties of individually doped Sm{sup 3+}, Eu{sup 3+} & co-doped (Sm{sup 3+} + Eu{sup 3+}) in BZn glasses were studied separately. • The effect of Eu{sup 3+} concentration on luminescence properties is explained from cross-relaxations. • Energy transfer from Sm{sup 3+} ({sup 4}G{sub 5/2}) to Eu{sup 3+} ({sup 5}D{sub 0}) has been explained from Foster–Dexter theory. • Dipole–dipole mechanism governs the energy transfer from Sm{sup 3+} to Eu{sup 3+}. - Abstract: The present paper reports on the results concerning to photoluminescence features of Eu{sup 3+}, Sm{sup 3+} ions and energy transfer process occurring from Sm{sup 3+} to Eu{sup 3+} doped in 45 B{sub 2}O{sub 3}–55 ZnO (BZn) glasses prepared by melt quenching technique. Luminescence quenching as a function of Eu{sup 3+} concentration in BZn glasses has been discussed. Among the studied concentrations, 0.5 mol% of Eu{sup 3+} is optimized because it has exhibited red emission transition {sup 5}D{sub 0} → {sup 7}F{sub 2}. With regard to Sm{sup 3+} glasses, orange emission at 602 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2}) has been noticed on exciting with λ{sub exci} = 403 nm. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm{sup 3+} and Eu{sup 3+} has been explained from the spectral overlap of Eu{sup 3+} absorption and Sm{sup 3+} emission. The optimized concentration 0.5 mol% of Eu{sup 3+} is co

Hydrothermal synthesis, characterization, and luminescence of Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers

Energy Technology Data Exchange (ETDEWEB)

Yang, Li; Wan, Yingpeng; Li, Yuze; Pu, Yinfu; Huang, Yanlin, E-mail: huang@suda.edu.cn [Soochow University, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science (China); Chen, Cuili; Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of)

2016-04-15

Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers were synthesized by the hydrothermal reaction method. The structural refinement was conducted on the base of the X-ray powder diffraction (XRD) measurements. The surface properties of the Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers were investigated by the measurements such as the scanning electron microscope (SEM), transmission electron microscope (TEM), and the energy dispersive spectrum (EDS). The nanofiber has a diameter of about 100 nm and a length of several micrometers. The luminescence properties such as photoluminescence excitation (PLE) and emission spectra (PL), decay lifetime, color coordinates, and the absolute internal quantum efficiency (QE) were reported. Ca{sub 2}B{sub 2}O{sub 5}:Eu{sup 3+} nanofibers show the red luminescence with CIE coordinates of (x = 0.41, y = 0.51) and the luminescence lifetime of 0.63 ms. The luminescence of Ca{sub 2}B{sub 2}O{sub 5}:Tb{sup 3+} nanofibers is green color (x = 0.29, y = 0.53) with the lifetime of 2.13 ms. However, Dy{sup 3+}-doped Ca{sub 2}B{sub 2}O{sub 5} nanofibers present a single-phase white-color phosphor with the fluorescence decay of 3.05 ms. Upon near-UV excitation, the absolute quantum efficiency is measured to be 65, 35, and 37 % for Eu{sup 3+}-, Tb{sup 3+}-, Dy{sup 3+}-doped Ca{sub 2}B{sub 2}O{sub 5} nanofibers, respectively. It is suggested that Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers could be an efficient phosphor for lighting and display.

Magnetism of cyano-bridged Ln3+-M3+ complexes. Part II: one-dimensional complexes (Ln3+ = Eu, Tb, Dy, Ho, Er, Tm; M3+ = Fe or Co) with bpy as blocking ligand.

Science.gov (United States)

Figuerola, Albert; Ribas, Joan; 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 13 one-dimensional complexes: trans-[M(CN)4(mu-CN)2Ln(H2O)4(bpy)]n.4nH2O.1.5nbpy (Ln = Eu3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Lu3+; M = Fe3+, Co3+). The structures for [EuFe]n (1), [TbFe]n (2), [DyFe]n (3), [HoFe]n (4), [ErFe]n (5), [TmFe]n (6), [LuFe]n (7), [EuCo]n (8), [TbCo]n (9), [DyCo]n (10), [HoCo]n (11), [ErCo]n (12), and [TmCo]n (13) have been solved: they crystallize in the triclinic space group P and are isomorphous. They exhibit a supramolecular architecture created by the interplay of coordinative, hydrogen bonding, and pi-pi interactions. A stereochemical study of the eight-vertex polyhedra of the lanthanide ions, based on continuous shape measures, is presented. The Ln3+-Fe3+ interaction is antiferromagnetic in [DyFe]n and [TbFe]n. For [EuFe]n, [HoFe]n, [ErFe]n, and [TmFe]n, there is no sign of any significant interaction. The magnetic behavior of [DyFe]n suggests the onset of weak long-range ferromagnetic ordering at 2.5 K.

SrAl2O4:Eu2+(,Dy3+ Nanosized Particles: Synthesis and Interpretation of Temperature-Dependent Optical Properties

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Huayna Terraschke

2015-01-01

Full Text Available SrAl2O4 nanosized particles (NPs undoped as well as doped with Eu2+ and Dy3+ were prepared by combustion synthesis for the discussion of their intensively debated spectroscopic properties. Emission spectra of SrAl2O4:Eu2+(,Dy3+ NPs are composed by a green band at 19 230 cm−1 (520 nm at room temperature, assigned to anomalous luminescence originated by Eu2+ in this host lattice. At low temperatures, a blue emission band at 22 520 cm−1 (444 nm is observed. Contrary to most of the interpretations provided in the literature, we assign this blue emission band very reliably to a normal 4f6(7FJ5d(t2g→4f7(8S7/2 transition of Eu2+ substituting the Sr2+ sites. This can be justified by the presence of a fine structure in the excitation spectra due to the different 7FJ levels (J=0⋯6 of the 4f6 core. Moreover, Fano antiresonances with the 6IJ (J=9/2,7/2 levels could be observed. In addition, the Stokes shifts (ΔES=1 980 cm−1 and 5 270 cm−1 for the blue and green emission, resp., the Huang-Rhys parameters of S=2.5 and 6, and the average phonon energies of ħω=480 cm-1 and 470 cm−1 coupled with the electronic states could be reliably determined.

An investigation on photoluminescence and energy transfer of Eu{sup 3+}/Sm{sup 3+} single-doped and co-doped Ca{sub 4}YO(BO{sub 3}){sub 3} phosphors

Energy Technology Data Exchange (ETDEWEB)

Bandi, Vengala Rao; Grandhe, Bhaskar Kumar [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Jang, Kiwan, E-mail: kwjang@changwon.ac.kr [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Shin, Dong-Soo [Department of Chemistry, Changwon National University, Changwon (Korea, Republic of); Yi, Soung-Soo [Department of Photonics, Silla University, Busan (Korea, Republic of); Jeong, Jung-Hyun [Department of Physics, Pukyong National University, Busan (Korea, Republic of)

2013-07-15

The present investigation aims to demonstrate the potentiality of Eu{sup 3+}/Sm{sup 3+} single-doped and co-doped Ca{sub 4}YO(BO{sub 3}){sub 3} phosphors, which were prepared by a sol–gel method. The X-ray diffraction (XRD) profiles showed that all the observed peaks could be attributed to the monoclinic phase of Ca{sub 4}YO(BO{sub 3}){sub 3}. From the measured emission profiles, we have noticed that both the single-doped Eu{sup 3+}/Sm{sup 3+} phosphors shows four emission transitions of {sup 5}D{sub 0} → {sup 7}F{sub 0,1,2,3} and {sup 4}G{sub 5/2} → {sup 6}H{sub 5/2,7/2,9/2,11/2} respectively. Among them, the {sup 5}D{sub 0} → {sup 7}F{sub 2} of Eu{sup 3+} and {sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} of Sm{sup 3+} are intense emission transitions, leading to an intense red color emission from the prepared phosphors. The excitation spectra showed that Eu{sup 3+}/Sm{sup 3+} doped samples can be excited efficiently by 394 nm and 402 nm respectively, incidentally which matches well with the characteristic emission from UVLED. The co-doping of Sm{sup 3+} ions can broaden and strengthen the absorption of near UV region and to be efficient to sensitize the emission of the Ca{sub 4}YO(BO{sub 3}){sub 3}:Eu{sup 3+} phosphor. The mechanism involved in the energy transfer between Eu{sup 3+} and Sm{sup 3+} has been explained and elucidated by an energy level diagram. - Highlights: • Eu{sup 3+} or/and Sm{sup 3+}:Ca{sub 4}YO(BO{sub 3}){sub 3} phosphors were prepared by sol–gel method. • The co-doping of Sm{sup 3+} to Ca{sub 4}YO(BO{sub 3}){sub 3}:Eu{sup 3+} extends its absorption of NUV region. • It has intense absorption in NUV region, which is suitable for NUV LED. • The energy transfer process between Eu{sup 3+} and Sm{sup 3+} ions were discussed.

Warm white light generation from single phase Sr{sub 3}Y(PO{sub 4}){sub 3}:Dy{sup 3+}, Eu{sup 3+} phosphors with near ultraviolet excitation

Energy Technology Data Exchange (ETDEWEB)

Huang, B.Y. [School of Physics & Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Feng, B.L. [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275 (China); Luo, L., E-mail: luoli@gdut.edu.cn [School of Physics & Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Han, C.L. [School of Physics & Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006 (China); He, Y.T.; Qiu, Z.R. [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275 (China)

2016-10-15

Highlights: • Novel single phase phosphors were synthesized in an ambient air atmosphere. • A direct band gap about 4.5 eV of the host is calculated for the first time. • It is suitable for near UV chip excitation. • It emits warm white light with better CIE and lower CCT over previous reports. • The thermal quenching is similar to that of YAG:0.06Ce{sup 3+} commercial phosphor. - Abstract: Novel Sr{sub 3}Y(PO{sub 4}){sub 3}:Dy{sup 3+}, Eu{sup 3+} (SYP:Dy{sup 3+}, Eu{sup 3+}) phosphors were synthesized by a standard solid-state reaction under an ambient air atmosphere and their structural and optical properties were investigated. XRD and diffuse reflectance spectra (DRS) were used to explore structural properties. The former showed that single phase phosphors were obtained and that the rare earth ions entered into the cubic host by substituting the smaller Y{sup 3+} ions and thereby enlarging the unit cell. The DRS indicated that the host has a direct bandgap of 4.5 eV. Under 393 nm excitation, a strong and stable warm white light emission with high color purity was achieved in SY{sub 0.92}P:0.06Dy{sup 3+}, 0.04Eu{sup 3+}. The energy transfer from Dy{sup 3+} to Eu{sup 3+} ions was investigated and the related mechanism was discussed based on the optical spectra and emission decay curves. The thermal quenching of emission is similar to that of YAG:0.06Ce{sup 3+}. The results show the single phase phosphor is potential in warm white LED.

Effect of annealing on luminescence of Eu{sup 3+}- and Sm{sup 3+}-doped Mg{sub 2}TiO{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Medić, Mina; Antić, Željka; Đorđević, Vesna [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Ahrenkiel, Phillip S. [South Dakota School of Mines & Technology, Rapid City, SD (United States); Marinović-Cincović, Milena [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Dramićanin, Miroslav D., E-mail: dramican@vinca.rs [University of Belgrade, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia)

2016-02-15

This work explores the influence of annealing temperature on the structure and luminescence of 2 at% Eu{sup 3+} and 1 at% Sm{sup 3+}-doped Mg{sub 2}TiO{sub 4} nanopowders produced via Pechini-type polymerized complex route. Mg{sub 2}TiO{sub 4} samples were annealed at 7 different temperatures (400 °C, 450 °C, 500 °C, 550 °C, 600 °C, 650 °C and 700 °C) to determine the temperature range in which cubic inverse spinel structure is stable and to follow the changes of material luminescence properties. X-ray diffraction revealed that crystallization of both Eu{sup 3+} and Sm{sup 3+}-doped Mg{sub 2}TiO{sub 4} nanopowders starts at 400 °C, and that Sm{sup 3+} doped Mg{sub 2}TiO{sub 4} starts to decompose at 650 °C, while Eu{sup 3+} doped Mg{sub 2}TiO{sub 4} starts to decompose at 700 °C. Samples annealed at higher temperatures show higher crystallinity and larger crystallite size. Mg{sub 2}TiO{sub 4} powder annealed at 600 °C is composed of ~5 nm size nanoparticles agglomerated in micron-size and dense chunks. The emission spectra of nanoparticles are composed of emissions from defects in Mg{sub 2}TiO{sub 4} host and characteristic emissions of Eu{sup 3+} ({sup 5}D{sub 0}→{sup 7}F{sub J}) and Sm{sup 3+} ({sup 4}G{sub 5/2}→{sup 6}H{sub J}) ions. The stronger emission and longer emission decays are observed with samples annealed at high temperatures. In the case of the Eu{sup 3+} ions emission intensity increased one order of magnitude between samples annealed at 400 °C and 650 °C. - Highlights: • Mg{sub 2}TiO{sub 4} nanoparticles of 5–10 nm in size are prepared by polymerized complex route. • Emission spectra and decays of Eu{sup 3+} and Sm{sup 3+} doped Mg{sub 2}TiO{sub 4} nanoparticles are shown. • Eu{sup 3+}(Sm{sup 3+}) doped Mg{sub 2}TiO{sub 4} can be annealed at temperatures <700 °C (650 °C). • Emission intensity of nanoparticles increases with increase of annealing temperature.

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.

Structural relative stabilities and pressure-induced phase transitions for lanthanide trihydrides REH{sub 3} (RE=Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu)

Energy Technology Data Exchange (ETDEWEB)

Kong Bo, E-mail: kong79@yeah.net [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900 (China); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Zhang Lin, E-mail: zhanglinbox@263.net [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Chen Xiangrong [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Zeng Tixian [College of Physics and Electronic Information, China West Normal University, Nanchong 637002 (China); Cai Lingcang [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900 (China)

2012-06-15

The structures, structural relative stabilities, pressure-induced phase transitions, and equations of state for lanthanide trihydrides REH{sub 3} (RE=Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu) are systematically studied using ab initio calculations under a core state model (CSM). The obtained ground-state parameters, such as lattice constants and bulk modulus, agree well with the available data. Among the P6{sub 3}/mm, P3-bar c1, and P6{sub 3}cm structures, the P6{sub 3}cm structure is found to be the most stable structure for lanthanide trihydride via the comparison of the calculated total energies. With the help of Birch-Murnaghan equation of state, the structural transitions from hexagonal to cubic for REH{sub 3} (RE=Sm, Gd, Ho, Er, and Lu) under pressure are affirmed; especially, the similar behavior of REH{sub 3} (RE= Tb, Dy, and Tm) is reasonably predicted for the first time by this means. For the transitions, the repulsive interactions of H-H atoms may play an important role in terms of the analysis of the structures in the vicinity of the theoretical phase transition.

Long-wave UVA radiation excited warm white-light emitting NaGdTiO4: Tm3+/Dy3+/Eu3+ ions tri-doped phosphors: Synthesis, energy transfer and color tunable properties

International Nuclear Information System (INIS)

Bharat, L. Krishna; Du, Peng; Yu, Jae Su

2016-01-01

NaGdTiO 4 (NGT) phosphors doped with different activator ions (Tm 3+ , Dy 3+ , and Eu 3+ ) were synthesized by a conventional solid-state reaction method in an ambient atmosphere. These phosphors were characterized by scanning electron microscope images, transmission electron microscope images, X-ray diffraction patterns, Fourier transform infrared spectra, and photoluminescence spectra. All the samples were crystallized in an orthorhombic phase with a space group of Pbcm (57). In Tm 3+ /Dy 3+ ions co-doped samples, white-light emission was observed under near-ultraviolet (NUV) excitation. In addition, the energy transfer between Tm 3+ and Dy 3+ ions was proved to be a resonant type via an electric dipole–dipole mechanism and the critical distance of energy transfer was calculated to be 19.91 Å. Furthermore, Tm 3+ /Dy 3+ /Eu 3+ ions tri-doped NGT phosphors demonstrated warm white-light emission by appropriately tuning the activator content, based on the principle of energy transfer. These NUV wavelength excitable phosphors exhibit great potential as a single-phase full-color emitting phosphor for white light-emitting diode applications. - Highlights: • The pebble shaped NaGdTiO 4 particles were prepared by solid-state reaction method. • Tm 3+ and Dy 3+ single doping gives respective blue and cool white light emission. • The Tm 3+ /Dy 3+ ions co-doped samples give CIE values near to standard white light. • Addition of Eu 3+ ions shifts the CIE values towards warm white light region. • This single phase white light emitting phosphors have lower CCT values (<5000 K).

Persistent luminescence, TL and OSL characterization of beta irradiated SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} combustion synthesized phosphor

Energy Technology Data Exchange (ETDEWEB)

Zúñiga-Rivera, N.J. [Departamento de Física, Posgrado en Nanotecnología, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico); García, R.; Rodríguez-Mijangos, R.; Chernov, V.; Meléndrez, R.; Pedroza-Montero, M. [Departamento de Investigación en Física, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico); Barboza-Flores, M., E-mail: mbarboza@cifus.uson.mx [Departamento de Investigación en Física, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico)

2014-05-01

The persistent luminescence (PLUM), thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of strontium aluminates co-doped with Eu{sup +2} and Dy{sup +3} exposed to beta radiation is reported. The phosphor was synthesized by the combustion synthesis method employing a highly exothermic redox reaction between the metal nitrates [Al(NO{sub 3}){sub 3}, Sr(NO{sub 3}){sub 2}, Eu(NO{sub 3}){sub 3} and Dy(NO{sub 3}){sub 3}] and organic fuel carbohydrazide (CH{sub 6}N{sub 4}O). The long decay PLUM emission, TL and OSL were measured as a function of beta radiation dose. A wide emission band centered at 510 nm (green) related to Eu{sup 2+} ions and lattice defects were observed for the synthesized samples. The presence of a variety of defects and aggregates were responsible for the observed broad 100 °C peaked TL glow curve of the irradiated sample which is composed of several overlapped TL peaks. The existence of multiple trapping levels, with different trapping/detrapping probabilities, is behind the particular features for the PLUM, TL and OSL emissions. We conclude that in the SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} phosphors, the low temperature TL peaked around 30–75 °C is responsible for the PLUM emission and those around 100 °C were related to very stable trapping states which provide suitable radiation storage properties to be used as a PLUM/TL/OSL radiation phosphor.

Online Determination of Sm, Eu and Yb in Environmental Samples by Inductively Coupled Plasma – Optical Emission Spectrometry

Directory of Open Access Journals (Sweden)

J. Dilip Kumar

2007-01-01

Full Text Available A procedure was developed for the determination of Sm, Eu and Yb in water samples by inductively coupled plasma-optical emission spectrometry (ICP-OES after preconcentration on synthesized 5-(4-pyridyl azo-8-quinolinol supported by Borassus flabellifer inflorescence (BFI. The sorbed element was subsequently eluted with 0.4 M HNO3 and the acid eluates were analyzed by ICP-OES. Under the optimal conditions, Sm, Eu and Yb in aqueous samples were concentrated 100-fold. Recoveries were obtained by the proposed method in the range of 98.6 -99.8%. This method was also applied for the analysis of spiked and natural water samples. The results provide strong evidence to support the hypothesis of an adsorption mechanism.

Studies on the preparation of ferric-hydroxide macro aggregate and hydroxyapatite particles labelled with Sm-153, Ho-166 and/or Dy-165 for radiation synovectomy

International Nuclear Information System (INIS)

Le Van So; Pham Ngoc Dien; Truong Hong Nghia; Nguyen Thi Thu; Nguyen Cong Duc; Vo Thji Cam Hoa; Bui Van Cuong

2004-01-01

The modified methods for the preparation of Hydroxyapatite particle (HA) and Ferric Hydroxide Macro Aggregated (FHMA of high stability and uniformity in particle size and of good geometrical shape suitable for production of radiolabeled carrier for radiation synovectomy purpose were developed. 165 Dy, 166 Ho and/or 153 Sm labeled HA and FHMA were produced using a simple labelling method. (author)

Enhanced luminescent properties of long-persistent Sr{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+}, Dy{sup 3+} phosphor prepared by the co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Pan Wen [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Zhongshan Road 158-43, Dalian Liaoning 116012 (China); Ning Guiling [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Zhongshan Road 158-43, Dalian Liaoning 116012 (China)], E-mail: ninggl@dlut.edu.cn; Zhang Xu; Wang Jing; Lin Yuan; Ye Junwei [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Zhongshan Road 158-43, Dalian Liaoning 116012 (China)

2008-12-15

Sr{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+}, Dy{sup 3+} phosphors were prepared by the (aminopropyl)-triethoxysilane (APTES) co-precipitation method. Effects of synthesis temperature on the crystal characteristics, luminescent properties and afterglow performance of Sr{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+}, Dy{sup 3+} phosphors have been discussed in detail and compared with the corresponding commercial product. The experimental results indicated that the sample could be synthesized at a relatively lower temperature and had better performance on the above-mentioned properties using the co-precipitation method.

Thermoelectric properties, crystal and electronic structure of semiconducting RECuSe{sub 2} (RE = Pr, Sm, Gd, Dy and Er)

Energy Technology Data Exchange (ETDEWEB)

Esmaeili, Mehdi [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Tseng, Yu-Chih [CANMET Materials, Natural Resources Canada, 183 Longwood Road South, Hamilton, Ontario L8P 0A5 (Canada); Mozharivskyj, Yurij, E-mail: mozhar@mcmaster.ca [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

2014-10-15

Highlights: • Crystal and electronic structure of monoclinic and trigonal RECuSe{sub 2} phases. • Thermoelectric properties of the RECuSe{sub 2} phases. • Temperature stability of the RECuSe{sub 2} phases. - Abstract: The ternary RECuSe{sub 2} phases have been prepared and structurally characterized. They adopt either a monoclinic structure (P2{sub 1}/c, z = 4) for lighter rare earths (RE = Pr, Sm and Gd) or Cu-disordered trigonal structure for heavier rare-earths (P3{sup ¯}m1, z = 1, RE = Dy and Er). The resistivity and Seebeck coefficient measurements on GdCuSe{sub 2}, DyCuSe{sub 2} and ErCuSe{sub 2} indicate that the studied phases are p-type semiconductors with relatively small activation energies (0.045–0.11 eV). However, their electrical resistivities are too high (0.45–220 Ω cm at room temperature) to make them competitive thermoelectric materials. Electronic structure calculations indicate presence of a band gap in the RECuSe{sub 2} phases.

Preparation of MAl O : Eu2+, Sm3+ (M = Ca, Sr, Ba) Phosphors by ...

African Journals Online (AJOL)

NJD

2007-10-15

Oct 15, 2007 ... clearly show that most peaks are assigned to those of the MAl2O4 structure. Moreover, their structures change with change of M. Samples A and B exhibit monoclinic crystal systems and sample. C a hexagonal structure. The doping Eu2+ and co-doping Sm3+ have very little influence on the structure of the ...

Tuning the luminescence color and enhancement of afterglow properties of Sr(4−x−y)CaxBayAl14O25:Eu2+,Dy3+ phosphor by adjusting the composition

International Nuclear Information System (INIS)

Luitel, Hom Nath; Watari, Takanori; Chand, Rumi; Torikai, Toshio; Yada, Mitsunori; Mizukami, Hiroshi

2013-01-01

Graphical abstract: Excitation and fluorescence emission spectra of three extreme compositions of Ca, Sr and Ba in Sr 4 Al 14 O 25 phosphor (viz. 4CaO·7Al 2 O 3 , 4SrO·7Al 2 O 3 and 4BaO·7Al 2 O 3 ) doped with 4 at% Eu 2+ and 8 at% Dy 3+ (inset shows the digital micrograph of corresponding phosphors). -- Highlights: • Bright phosphor, Sr (4−x−y) Ca x Ba y Al 14 O 25 :Eu 2+ ,Dy 3+ , was synthesized by adjusting the composition. • The solid solubility of Ca and Ba in the Sr 4 Al 14 O 25 host was determined to be 20 and 10 mol%, respectively. • Substituting part of Sr by Ca, the emission color can be well tuned from blue to green. • A white afterglow was observed when 3.2 mol of Sr was substituted by Ca. • The afterglow luminescence was enhanced by 1.5 times by 0.2 mol Ca substitution. -- Abstract: Color point tuning is an important challenge for improving the practical applications of various displays, especially there are very limited white color single hosts that emits in the white spectrum. In this paper, the possibility of color tuning by substituting part of host lattice cation (Sr 2+ ions) by Ca 2+ or Ba 2+ ions in an efficient strontium aluminate phosphor, Sr 4 Al 14 O 25 :Eu 2+ ,Dy 3+ , is reported and found to be very promising for displays. A detail study by replacing part of Sr 2+ with Ca 2+ or Ba 2+ has been investigated. X-ray diffraction study showed that crystal structure of Sr 4 Al 14 O 25 is preserved up to 20 mol of Ca 2+ ion exchange while it is limited to 10 mol of Ba 2+ ions exchange. Substantial shift in the emission band and color were observed by substitution of Sr 2+ by Ca 2+ or Ba 2+ ions. A bluish-white emission and afterglow was observed at higher Ca 2+ ions substitution. Further, partial Ca 2+ substitutions (up to 0.8 mol) resulted in enhanced afterglow of Sr 4 Al 14 O 25 :Eu 2+ ,Dy 3+ phosphor. However, Ba 2+ substitution decreased the fluorescence as well afterglow of the Sr 4 Al 14 O 25 :Eu 2+ ,Dy 3+ phosphor

Preparation of MAl 2 O 4 : Eu 2+ , Sm 3+ (M = Ca, Sr, Ba) Phosphors ...

African Journals Online (AJOL)

A series of MAl2O4: Eu2+, Sm3+ (M = Ca, Sr, Ba) phosphors was prepared by the combustion method, and the influence of these alkaline earth metals on the structure and luminescent performances for these phosphors was investigated. A relationship was established between their composition, crystallization capacity and ...

Charge Density Wave in the New Polymorphs of RE ₂ Ru ₃ Ge ₅ ( RE = Pr, Sm, Dy)

Energy Technology Data Exchange (ETDEWEB)

Bugaris, Daniel E.; Malliakas, Christos D.; Han, Fei; Calta, Nicholas P.; Sturza, Mihai; Krogstad, Matthew J.; Osborn, Raymond; Rosenkranz, Stephan; Ruff, Jacob P. C.; Trimarchi, Giancarlo; Bud’ko, Sergey L.; Balasubramanian, Mahalingam; Chung, Duck Young; Kanatzidis, Mercouri G.

2017-02-16

A new polymorph of the RE₂Ru₃Ge₅ (RE = Pr, Sm, Dy) compounds has been grown as single crystals via an indium flux. These compounds crystallize in tetragonal space group P4/mnc with the Sc₂Fe₃Si₅-type structure, having lattice parameters a = 11.020(2) Å and c = 5.853(1) Å for RE = Pr, a = 10.982(2) Å and c = 5.777(1) Å for RE = Sm, and a = 10.927(2) Å and c = 5.697(1) Å for RE = Dy. These materials exhibit a structural transition at low temperature, which is attributed to an apparent charge density wave (CDW). Both the high-temperature average crystal structure and the low-temperature incommensurately modulated crystal structure (for Sm₂Ru₃Ge₅ as a representative) have been solved. The charge density wave order is manifested by periodic distortions of the onedimensional zigzag Ge chains. From X-ray diffraction, charge transport (electrical resistivity, Hall effect, magnetoresistance), magnetic measurements, and heat capacity, the ordering temperatures (T_CDW) observed in the Pr and Sm analogues are ~200 and ~175 K, respectively. The charge transport measurement results indicate an electronic state transition happening simultaneously with the CDW transition. X-ray absorption near-edge spectroscopy (XANES) and electronic band structure results are also reported.

Tunable-color luminescence via energy transfer in NaCa13/18Mg5/18PO4:A (A = Eu2+/Tb3+/Mn2+, Dy3+) phosphors for solid state lighting.

Science.gov (United States)

Li, Kai; Fan, Jian; Mi, Xiaoyun; Zhang, Yang; Lian, Hongzhou; Shang, Mengmeng; Lin, Jun

2014-11-17

A series of NaCa13/18Mg5/18PO4(NCMPO):A (A = Eu(2+)/Tb(3+)/Mn(2+), Dy(3+)) phosphors have been prepared by the high-temperature solid-state reaction method. The X-ray diffraction (XRD) and Rietveld refinement, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), cathodoluminescence (CL), decay lifetimes, and PL quantum yields (QYs) were utilized to characterize the phosphors. The pure crystalline phase of as-prepared samples has been demonstrated via XRD measurement and Rietveld refinements. XPS reveals that the Eu(2+)/Tb(3+)/Mn(2+) can be efficiently doped into the crystal lattice. NCMPO:Eu(2+)/Tb(3+)/Mn(2+) phosphors can be effectively excited under UV radiation, which show tunable color from purple-blue to red including white emission based on energy transfer from Eu(2+) to Tb(3+)/Mn(2+) ions. Under low-voltage electron beam bombardment, the NCMPO:A (A = Eu(2+)/Tb(3+)/Mn(2+), Dy(3+)) display their, respectively, characteristic emissions with different colors, and the CL spectrum of NCMPO:0.04Tb(3+) has the comparable intensity to the ZnO:Zn commercial product. In addition, the calculated CIE coordinate of NCMPO:0.04Tb(3+) (0.252, 0.432) is more saturated than it (0.195, 0.417). These results reveal that NCMPO:A (A = Eu(2+)/Tb(3+)/Mn(2+), Dy(3+)) may be potential candidate phosphors for WLEDs and FEDs.

Chemical Bond Parameters in Sr3MRhO6 (M=Rare earth)

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

Chemical bond parameters, that is, bond covalency, bond valence, macroscopic linear susceptibility, and oxidation states of elements in Sr3MRhO6 (M=Sm, Eu, Tb, Dy, Ho, Er, Yb) have been calculated. The results indicate that the bond covalency of M-O decreases sharply with the decrease of ionic radius of M3+ from Sm to Yb, while no obvious trend has been found for Rh-O and Sr-O bonds. The global instability index indicates that the crystal structures of Sr3MrhO6 (M = Sm, Eu, Tb, Dy, Ho) have strained bonds.

Two structure types based on Si6O15 rings: synthesis and structural and spectroscopic characterisation of Cs1.86K1.14DySi6O15 and Cs1.6K1.4SmSi6O15

International Nuclear Information System (INIS)

Wierzbicka-Wieczorek, Maria; Goeckeritz, Martin; Kolitsch, Uwe; Lenz, Christoph; Giester, Gerald

2015-01-01

The silicate Cs 1.86 K 1.14 DySi 6 O 15 represents a mixed tetrahedral-octahedral framework structure type based on roughly circular Si 6 O 15 rings and isolated DyO 6 octahedra. The silicate Cs 1.6 K 1.4 SmSi 6 O 15 has a layered atomic arrangement built from corrugated Si 6 O 15 layers containing four-, six- and eight-membered rings. The layers are connected by isolated SmO 6 octahedra to form a mixed tetrahedral-octahedral framework. This structure shows a close structural relationship to β-K 3 NdSi 6 O 15 and a less close one to dehydrated elpidite (Na 2 ZrSi 6 O 15 ). In both structures, Cs/K atoms occupy large voids. The silicates were obtained through high-temperature flux syntheses. Their crystal structures have been determined from single-crystal X-ray diffraction data. Cs 1.86 K 1.14 DySi 6 O 15 crystallises in R32 (no. 155) with a = 13.896(2), c = 35.623(7) Aa and V = 5957.2(17) Aa 3 , whereas Cs 1.6 K 1.4 SmSi 6 O 15 crystallises in Cmca (no. 64) with a = 14.474(3), b = 14.718(3), c = 15.231(3) Aa and V = 3244.7(11) Aa 3 . The Dy 3+ and Sm 3+ cations present in the silicates cause PL emission bands in the visible yellow-to-orange spectral range. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Solid Oxide Galvanic Cell to determine thermochemical data of Dy6UO12(s)

International Nuclear Information System (INIS)

Sahu, Manjulata; Dash, Smruti; Sen, B.K.; Venugopal, V.

2010-01-01

The rare earth elements such as Sm, Eu, Gd, and Dy have very high thermal neutron absorption cross sections and their oxides are utilized as burnable poisons in nuclear reactor to maintain constant reactivity of the core. These oxides form solid solution with urania as their ionic radii are within 20% of that of urania. Rare earth oxides-urania solid solutions are also beneficial in preventing oxidation of UO 2 (s). RE 6 UO I2 (s) (RE = rare earth) type of compounds are known to exist in RE-U-O system and their formation cannot be ruled out under transient conditions. The data on Gibbs energy of formation of compounds in RE-U-O system is therefore essential to predict the feasibility. Theoretically, the measurement of the e.m.f. of a suitable galvanic cell is one of the most accurate methods to obtain Gibbs energy of formation of compounds if e.m.f cell operates reversibly. In this study, the standard molar Gibbs energy of formation of Dy 6 UO I2 (s) was determined using solid oxide galvanic cell technique. The Gibbs energy of formation of Dy 6 UO 12 (s) is reported for the first time

Time-Resolved Detection of Fingermarks on Non-Porous and Semi-Porous Substrates Using Sr2MgSi2O7:Eu2+, Dy3+ Phosphors.

Science.gov (United States)

Xiong, Xiaobo; Yuan, Ximing; Song, Jiangqi; Yin, Guoxiang

2016-06-01

Eu(2+), Dy(3+) co-doped strontium-magnesium silicate phosphors, Sr2MgSi2O7:Eu(2+), Dy(3+) (SMSEDs), have shown great potential in optoelectronic device due to their unique luminescent property. However, their potential applications in forensic science, latent fingermark detection in particular, are still being investigated. In this contribution, SMSEDs were successfully employed to latent fingermarks on a variety of non-porous and semi-porous surfaces, including aluminum foil, porcelain, glass, painted wood, colored paper, and leather. All the results illustrated that this luminescent powder, as a long-lasting phosphorescence material (LLP), was an ideal time-resolved detection reagent of fingermark for elimination of background interferences from various difficult substrates, and offered a good contrast to allow their identification without the need to enhance the results compared to nanosized organic fluorescent powder. © The Author(s) 2016.

Use of dispersive liquid-liquid microextraction for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium

International Nuclear Information System (INIS)

Mallah, M.H.; Atomic Energy Organization of Iran, Tehran; Shemirani, F.; Ghannadi Maragheh, M.

2008-01-01

A new preconcentration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol (PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78 were obtained for Sm, Eu, Gd and Dy, respectively. (author)

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.

Investigations on the determination of traces of some rare earths (Eu, Sm, Gd, Y) in oxides of rare earths (Y2O3, Sm2O3, Gd2O3) by emission spectrography in d.c. arc

International Nuclear Information System (INIS)

Dittrich, K.; Gajek, M.; Luan, P.

1978-01-01

The evaporation of traces and matrices of rare earth elements was investigated in different atmospheres. It was found, that low-boiling rare earths elements, because of their extended formation of carbides evaporate more slowly than high-boiling rare earths elements. The evaporation of the traces depends on the matrices. 3 cases for the determination of traces of rare earths elements in oxides of other rare earths elements are derived from the results of the evaporation: Low- to high-boiling traces of rare earths elements in low-boiling matrices of rare earths elements, low-boiling traces in medium- to high-boiling matrices, and medium- to high-boiling traces in medium- to high-boiling matrices. The results of the determination are: in Y 2 O 3 : 14 ppm Sm, 2 ppm Eu; in Gd 2 O 3 : 18 ppm Y, 3 ppm Sm, 2 ppm Eu; in Sm 2 O 3 : 70 ppm Y, 370 ppm Gd, 16 ppm Eu. (author)

Dose effects on the long persistent luminescence properties of beta irradiated SrAl2O4:Eu2+, Dy3+ phosphor

International Nuclear Information System (INIS)

Pedroza-Montero, M.; Castaneda, B.; Gil-Tolano, M.I.; Arellano-Tanori, O.; Melendrez, R.; Barboza-Flores, M.

2010-01-01

The SrAl 2 O 4 :Eu 2+ , Dy 3+ is a phosphor characterized by a long persistent luminescence (PLUM) when it is excited with UV-VIS light and ionizing radiation. In this paper, we study the PLUM behavior as a function of beta irradiation dose in the 0-650 Gy range with a fixed dose rate of 5 Gy/min. The PLUM intensity showed a complex decay behavior, exhibiting a near linear response in the 0-1.7 Gy low dose range and gradually increasing up to 160 Gy. The PLUM reached the saturation for higher doses (>275 Gy) with a slight decrease in the range of 300-650 Gy. In addition, a systematic PLUM enhancement was produced after a thermal cleaning procedure and irradiation at RT in a series of 10 cycles. The observed phenomenon may be related to a radiation-induced process of charge trapping accumulation, which is triggered by thermal stimulation during the irradiation stage. It improves the luminescent characteristics of SrAl 2 O 4 :Eu 2+ , Dy 3+ phosphors rendering them suitable for permanent display and illumination devices.

Synthesis and thermoluminescence of new Li2SO4:Eu and Li2SO4:Dy phosphors exposed to beta radiation

International Nuclear Information System (INIS)

Garcia H, A. R.; Bustamante L, G. A.; Castro C, A. I.; Bernal H, R.; Cruz V, C.; Burruel I, S. E.; Castano M, V. M.

2015-10-01

Full text: Li 2 SO 4 is systematically studied for the very first concerning their dosimetric capabilities. Pellet- shaped Eu and Dy doped Li 2 SO 4 phosphors were synthesized by sintering. Some samples were exposed to beta particle irradiation in order to investigate their thermoluminescence (Tl) features. Glow curves were obtained for 80 mg mass samples, showing that both, Tl sensitivity as well as the temperature at which the Tl maximum is recorded, depends upon the sample dopant. The glow curves of Li 2 SO 4 :Eu exhibit two maxima, located at 433 and 573 K, when a 5 K/s heating rate was used, being the most intense emission that observed at 573 K. The integrated Tl increases as the radiation dose was increased in the 0.25 - 5 Gy range, with no shift of the Tl maxima being observed, meaning that first order kinetics processes are involved in the Tl emission. The normalized sensitivity recorded in ten consecutive irradiation-Tl readout cycles shows a good reusability with only 5 % variability. The integrated Tl fades as a function of the elapsed time between irradiation and the corresponding Tl readout of Eu and Dy doped Li 2 SO 4 phosphors is obtained. From the obtained results, we conclude that Li 2 SO 4 is a promising phosphor material to develop high performance Tl dosimeters, and a long term research work focused to understand and to improve their Tl features is absolutely justified. (Author)

Eu2+,Dy3+ codoped SrAl2O4 nanocrystalline phosphor for latent fingerprint detection in forensic applications

International Nuclear Information System (INIS)

Sharma, Vishal; Das, Amrita; Kumar, Vinay

2016-01-01

In this work, europium and dysprosium doped strontium aluminate (SrAl 2 O 4 :Eu 2+ ,Dy 3+ ) nanophosphor is synthesized and its novel application for the detection of latent fingerprints on various contact surfaces is reported. The SrAl 2 O 4 :Eu 2+ ,Dy 3+ is synthesized using a combustion method and shows long-lasting afterglow luminescence. The powder particles are characterized using field emission scanning electron microscopy (FE-SEM), SEM–energy dispersive x-ray analysis, x-ray diffraction and photoluminescence spectrophotometry. The FE-SEM image analysis reveals that the nanoparticles are mostly 8–15 nm in size with an irregular spherical shape. This nano-structured powder was applied to fresh and aged fingerprints deposited on porous, semi-porous and non-porous contact surfaces, such as ordinary colored paper, glossy paper, glass, aluminum foil, a yellow foil chocolate wrapper, a soft drink can, a PET bottle, a compact disc and a computer mouse. The results are reproducible and show great sensitivity and high contrast in the developed fingermark regions on these surfaces. These nanophosphor particles also show a strong and long-lasting afterglow property, making them a suitable candidate for use as a fingerprint developing agent on luminescent and highly patterned surfaces. These kinds of powders have shown that they can remove the interference from background luminescence, which is not possible using ordinary luminescent fingerprinting powders. (paper)

Synthesis and electrical properties of Y{sub 2}O{sub 3}: Dy{sup 3+} and Eu{sup 3+} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Jyotsana, Aradhana; Maurya, Gulab Singh; Rai, Awadhesh K.; Ghosh, B.K. [University of Allahabad, Department of Physics, Allahabad (India); Srivastava, Anoop K. [University of Allahabad, Nanotechnology Application Center, Allahabad (India)

2014-11-15

Yttrium oxide (Y{sub 2}O{sub 3}) doped with Dy{sup 3+} and Eu{sup 3+} nanoparticle has been synthesized by solution combustion method. The formation of the compounds has been checked by X-ray diffraction method. The crystallite/particle size has been measured using Scherrer formula as well as by transmission electron microscopy which show that the size of the particles are in the nanorange. The frequency and temperature dependent variation of impedance Z*, dielectric constant (ε'), dielectric loss (ε'') and AC conductivity (σ) of Y{sub 2}O{sub 3}: Dy{sup 3+} and Eu{sup 3+} nanoparticles were also measured. The real and imaginary part of complex impedance makes semicircle in the complex plane. The center of semicircle arc is found to be shifted toward higher value of real part of impedance with increasing temperature. This indicates that the conductivity of the material increases with the increase in temperature. Cole-Cole plots demonstrate that the dielectric relaxation process occurs in the material. The AC conductivity (σ {sub AC}) increases with the increase in temperature within the frequency range of 10{sup 3}-10{sup 7} Hz confirming the hopping of the electrons in the conduction process. The value of impedance decreases sharply with increasing frequency and attains minimum value after 10{sup 5} Hz at all temperatures. (orig.)

Study of a new dosimetric radio-thermoluminescent systems

International Nuclear Information System (INIS)

Cazac, T.C.

1980-01-01

This is the first Romanian study to investigate conditions to obtain the radio-thermo-luminescent systems: MgB 4 O 7 :A(A-Nd,Sm,Eu,Dy,Tb,Dy+Sm and Tb+Sm) MgF 2 A (A=Mn,Dy,Tb,Sm,Li), their essential dosimetric characters, as well as the (MgF 2 =Mn) thermophosphorus mixture with a ( 6 LiF) lithium target. An investigation was developed upon a new category of radio-thermoluminescent detectors with low radiation energy dependence and fading, magnesjum boride activated by several elements of the lanthanides class (Nd,Sm,Eu,Dy,Tb). A new radio-thermoluminescent dosimetric system with high sensitivity and moderate dependence on energy radiation - (Mnsup(2+)) manganese activated magnesium fluoride - was also studied. The author explored application of investigated detectors MgF 2 =Mn, MgB 4 O 7 =Dy and MgB 4 O 7 :Tb in neutron dosimetry in complex gamma-neutron fields. It is deemed that by using the dosimetric systems reported in the thesis in order to measure gamma, beta and neutron radiation doses, dosimetric control can be ensured both in professional dosimetry and in nuclear accident dosimetry, as well as in various basic and applicative investigations. A modest contribution is thus made towards achieving the national nuclear program through an extension of the thermophosphorus range with practical applications in nuclear radiation dosimetry. (author)

Blue–green afterglow of BaAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors

Energy Technology Data Exchange (ETDEWEB)

Zhai, Bao-gai [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China); Ma, Qing-lan [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China); School of Electronics and Information, Nantong University, Jiangsu 226019 (China); Xiong, Rui [School of Physics and Technology, Wuhan University, Hubei 430072 (China); Li, Xiazhang [Analysis and Testing Center, Changzhou University, Jiangsu 213164 (China); Huang, Yuan Ming, E-mail: dongshanisland@126.com [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China)

2016-03-15

Highlights: • Afterglow can be achieved when Eu{sup 2+} is absent in the DyAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors. • The afterglow of DyAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors is discernible to naked eyes for minutes. • Dy{sup 3+} introduced trap centers are believed to be responsible for the afterglow. - Abstract: Dy{sup 3+} doped barium aluminate (BaAl{sub 2}O{sub 4}:Dy{sup 3+}) phosphors were prepared via the sol–gel combustion route at the ignition temperature of 600 °C. The phosphors were characterized with X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Regardless of the absence of Eu{sup 2+} luminescent centers, broadband blue–green afterglow with its peak at about 490 nm was recorded in the BaAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors. The decay profile of the blue–green afterglow can be best fitted into a two-component exponential function with the two lifetime decay constants to be 8.81 and 45.25 s, respectively. The observation of blue–green afterglow from BaAl{sub 2}O{sub 4}:Dy{sup 3+} in the absence of Eu{sup 2+} provides unique opportunity in unveiling the afterglow mechanisms of rare-earth doped alkaline-metal aluminates. Possible mechanisms on the blue–green afterglow in BaAl{sub 2}O{sub 4}:Dy{sup 3+} phosphors are discussed in terms of the Dy{sup 3+} ions introduced trap centers as well as luminescent centers in the crystal lattice.

Enhancing the Photocatalytic Activity of Sr4 Al14 O25 : Eu2+ , Dy3+ Persistent Phosphors by Codoping with Bi3+ Ions.

Science.gov (United States)

García, Carlos R; Oliva, Jorge; Romero, Maria Teresa; Diaz-Torres, Luis A

2016-03-01

The photocatalytic activity of Bismuth-codoped Sr 4 Al 14 O 25 : Eu 2+ , Dy 3+ persistent phosphors is studied by monitoring the degradation of the blue methylene dye UV light irradiation. Powder phosphors are obtained by a combustion synthesis method and a postannealing process in reductive atmosphere. The XRD patterns show a single orthorhombic phase Sr 4 Al 14 O 25 : Eu 2+ , Dy 3+ , Bi 3+ phosphors even at high Bismuth dopant concentrations of 12 mol%, suggesting that Bi ions are well incorporated into the host lattice. SEM micrographs show irregular micrograins with sizes in the range of 0.5-20 μm. The samples present an intense greenish-blue fluorescence and persistent emissions at 495 nm, attributed to the 5d-4f allowed transitions of Eu 2+ . The fluorescence decreases as Bi concentration increases; that suggest bismuth-induced traps formation that in turn quench the luminescence. The photocatalytic evaluation of the powders was studied under both 365 nm UV and solar irradiations. Sample with 12 mol% of Bi presented the best MB degradation activity; 310 min of solar irradiation allow 100% MB degradation, whereas only 62.49% MB degradation is achieved under UV irradiation. Our results suggest that codoping the persistent phosphors with Bi 3+ can be an alternative to enhance their photocatalytic activity. © 2016 The American Society of Photobiology.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-11-17

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

Effects of calcining temperatures of Eu{sup 2+} and Dy{sup 3+} ion-codoped calcia-alumina binary compounds on their phase transition and luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Liang, Chen-Jui, E-mail: cjliang@fcu.edu.tw; Siao, Hao-Yi

2017-06-01

attributed to the Dy{sup 3+4}F{sub 9/2} → {sup 6}H{sub j} (j = 11/2, 13/2, 15/2) transition when the temperature was higher than 900 °C. Finally, the energy transitions of Eu{sup 2+}, Eu{sup 3+}, and Dy{sup 3+} and the nephelauxetic effect and crystal field are discussed. - Highlights: • Investigate the phases in crystallization stage of calcia-alumina binary system. • Describe the effect of phases in structure on the luminescence properties. • Depict the mechanism of white light photoluminescence. • Construe the energy levels for electron transitions of the Eu{sup 2+}, Eu{sup 3+}, and Dy{sup 3+}.

Complexes of o-Vanillin oxime with La(III), Ce(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) and Yb(III)

International Nuclear Information System (INIS)

Dhar, M.L.; Gupta, V.K.; Singh, Onkar

1988-01-01

Ten complexes of lanthanides with o-vanillin oxime have been swynthesised and characterised. The composition of the complexes as determined by elemental and thermal analyses, infrared electronic spectral and magnetic moment studies is [Ln(C 8 H 8 NO 3 ) 3 .XH 2 O], where X=2 when Ln=La, Ce, Pr, Nd, Sm and X=3 when Ln=Gd, Dy, Tb, Ho, Yb; C 8 H 8 NO 3 - represents the anion of the ligand. (author). 16 refs., 2 figs., 2 tables

Synthesis, structure and luminescence properties of binary and ternary complexes of lanthanide (Eu{sup 3+}, Sm{sup 3+} and Tb{sup 3+}) with salicylic acid and 1,10-phenanthroline

Energy Technology Data Exchange (ETDEWEB)

Shen, Chen-Qi; Yan, Tian-Lu; Wang, Yi-Ting; Ye, Zi-Jun; Xu, Cun-Jin, E-mail: cjxu@hznu.edu.cn; Zhou, Wen-Jun

2017-04-15

A series of binary and ternary complexes of lanthanide (Eu{sup 3+}, Sm{sup 3+} and Tb{sup 3+}) with salicylic acid (Hsal) and 1,10-phenanthroline (phen) were synthesized, and characterized by element analysis, coordination titration analysis, IR, UV and TG-DTA. Their compositions were (NH{sub 4})[Ln(sal){sub 4}(H{sub 2}O){sub 2}] (Ln=Eu (1), Sm (2), Tb (3)) and (NH{sub 4})[Ln(sal){sub 4}(phen){sub 2}] (Ln=Eu (4), Sm (5), Tb (6)), respectively. In particular, the ternary complex of Eu{sup 3+}, 4, was characterized by X-ray diffraction, and luminescence intensities of binary and ternary complexes were compared. In case of Eu{sup 3+} and Sm{sup 3+} complexes, ternary complexes emitted stronger luminescence than corresponding binary complexes of salicylic acid and Ln{sup 3+}. On the other hand, the ternary Tb{sup 3+} complex had weaker luminescence than the binary complex because of back energy transfer from Tb{sup 3+} to phen. The CIE coordinates of 1–6 were calculated as (0.65, 0.35), (0.52, 0.48), (0.33, 0.59), (0.67, 0.33), (0.62, 0.38) and (0.36, 0.58), respectively, which enable these complexes to be promising candidates for red, green, or yellow component in OLEDs.

Long-wave UVA radiation excited warm white-light emitting NaGdTiO{sub 4}: Tm{sup 3+}/Dy{sup 3+}/Eu{sup 3+} ions tri-doped phosphors: Synthesis, energy transfer and color tunable properties

Energy Technology Data Exchange (ETDEWEB)

Bharat, L. Krishna; Du, Peng; Yu, Jae Su, E-mail: jsyu@khu.ac.kr

2016-05-05

NaGdTiO{sub 4} (NGT) phosphors doped with different activator ions (Tm{sup 3+}, Dy{sup 3+}, and Eu{sup 3+}) were synthesized by a conventional solid-state reaction method in an ambient atmosphere. These phosphors were characterized by scanning electron microscope images, transmission electron microscope images, X-ray diffraction patterns, Fourier transform infrared spectra, and photoluminescence spectra. All the samples were crystallized in an orthorhombic phase with a space group of Pbcm (57). In Tm{sup 3+}/Dy{sup 3+} ions co-doped samples, white-light emission was observed under near-ultraviolet (NUV) excitation. In addition, the energy transfer between Tm{sup 3+} and Dy{sup 3+} ions was proved to be a resonant type via an electric dipole–dipole mechanism and the critical distance of energy transfer was calculated to be 19.91 Å. Furthermore, Tm{sup 3+}/Dy{sup 3+}/Eu{sup 3+} ions tri-doped NGT phosphors demonstrated warm white-light emission by appropriately tuning the activator content, based on the principle of energy transfer. These NUV wavelength excitable phosphors exhibit great potential as a single-phase full-color emitting phosphor for white light-emitting diode applications. - Highlights: • The pebble shaped NaGdTiO{sub 4} particles were prepared by solid-state reaction method. • Tm{sup 3+} and Dy{sup 3+} single doping gives respective blue and cool white light emission. • The Tm{sup 3+}/Dy{sup 3+} ions co-doped samples give CIE values near to standard white light. • Addition of Eu{sup 3+} ions shifts the CIE values towards warm white light region. • This single phase white light emitting phosphors have lower CCT values (<5000 K).

Synthesis and luminescence properties of ZnAl{sub 2}O{sub 4}:RE{sup 3+} (RE = Eu, Sm) phosphors

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Jin; Cho, Shin Ho [Silla University, Busan (Korea, Republic of)

2014-01-15

ZnAl{sub 2}O{sub 4}:RE{sup 3+} (RE = Eu or Sm) phosphor powders were synthesized with different concentrations of activator ions by using the conventional solid-state reaction method. The effects of the concentration of activator ions on the structural, morphological, and luminescent properties of zinc aluminate phosphors were investigated. The X-ray diffraction patterns revealed that the phosphors synthesized with different concentrations of activator ions showed mixed phases of ZnAl{sub 2}O{sub 4}, ZnO, and Al{sub 2}O{sub 3}. The crystallite size was estimated using the Scherrer formula, and the maximum size was obtained for 0.20 mol of Eu{sup 3+} ions. The emission spectra of of Eu{sup 3+}-doped ZnAl{sub 2}O{sub 4} phosphors under excitation at 303 nm exhibited one intense green band at approximately 520 nm and three weak bands centered at 590, 621, and 701 nm, respectively. The intensity of all the emission bands reached a maximum for 0.05 mol of Eu{sup 3+} ions. For the Sm{sup 3+}-doped ZnAl{sub 2}O{sub 4} phosphors, a broad emission band peak at 526 nm and several weak lines in the range 470 - 700 nm were observed. The results suggest that the luminescent intensity of the phosphors can be enhanced by controlling the amount of activator ions incorporated into the host lattice.

Structural and luminescence properties of SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+},Nd{sup 3+} phosphor thin films grown by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Wako, A.H., E-mail: wakoah@ufs.ac.za [Department of Physics, University of the Free State, QwaQwa Campus, Private Bag X13, Phuthaditjhaba 9866 (South Africa); Dejene, F.B. [Department of Physics, University of the Free State, QwaQwa Campus, Private Bag X13, Phuthaditjhaba 9866 (South Africa); Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA-9300 (South Africa)

2016-01-01

Thin films of Eu{sup 2+} doped and Dy{sup 3+},Nd{sup 3+} co-doped Strontium Aluminate (SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+},Nd{sup 3+}) phosphors were grown on Si(100) substrates by a pulsed laser deposition (PLD) technique using a 266 nm Nd:YAG pulsed laser under varying substrate temperature and the working atmosphere during the film deposition process. The effect of substrate temperatures and argon partial pressure on the structure and luminescence properties of the as-deposited SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+},Nd{sup 3+} phosphor thin films were analysed. XRD patterns showed that with increasing substrate temperature and argon partial pressure the peaks in the direction (220) shifted to the lower 2-theta angles. Photoluminescence (PL) data collected in air at room temperature revealed a slight shift in the peak wavelength of the PL spectra observed from the thin films when compared to the PL spectra of the phosphor in powder form, which is probably due to a change in the crystal field. The PL intensity of the samples was highest for 100 °C substrate temperature and 20 mTorr argon partial pressure. Due to this, the effect of argon partial pressure was studied at a constant substrate temperature of 100 °C while the effect of Substrate temperatures recorded at 20 mTorr argon pressure respectively.

Optimization and complexing agent-assisted synthesis of green SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+} phosphors through sol–gel process

Energy Technology Data Exchange (ETDEWEB)

Du, Hongli; Shan, Wenfei; Wang, Liying; Xu, De; Yin, Hao [School of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Chen, Yanwen [Hunan Labour Protection Institute of Nonferrous Metals, Changsha 410014 (China); Guo, Dongcai, E-mail: dcguo2001@hnu.edu.cn [School of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Hunan Provincial Key Laboratory for Cost-effective Utilization of Fossil Fuel Aimed at Reducing Carbon-dioxide Emissions, Changsha 410082 (China)

2016-08-15

A novel Eu{sup 2+}–Dy{sup 3+}co-doped strontium aluminate green long-lasting phosphors were synthesized via conventional sol–gel method with citric acid and polyethylene glycol used as chelating agent, respectively. Orthogonal experiments were employed to optimize the main synthesis conditions and obtain the optimum technological parameters. Subsequently, the crystal structure, morphology, decay curve and luminescence property of the composites were characterized. X-ray diffraction (XRD) showed that the samples were composed of single-phase SrAl{sub 2}O{sub 4}. Scanning electron microscopy (SEM) revealed that the resultant nanoparticles performed graininess with a size of 100 nm around. The excitation and emission spectra indicated that, excitation broadband chiefly lay in the ultraviolet range, and nanocrystalline particles emitted strong light at 510 nm, which corresponding to the typical characteristic 5d–4f transition of Eu{sup 2+} ion excited at around 360 nm. The long afterglow photoluminescence of nanoparticles SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+} (denoted as SAO: ED) was observed in the dark with the naked eye even after the removal of the excitation light. The luminescence properties suggested that SAO: ED phosphor may be regarded as a potential green phosphor candidate for near-UV and blue light-emitting diodes (LEDs).

Strong broad green UV-excited photoluminescence in rare earth (RE = Ce, Eu, Dy, Er, Yb) doped barium zirconate

Energy Technology Data Exchange (ETDEWEB)

Borja-Urby, R. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico); Diaz-Torres, L.A., E-mail: ditlacio@cio.mx [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Ciudad de Mexico, D. F. 07730 (Mexico); Meza, O. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico)

2011-10-25

Highlights: > Trivalent rare earth (RE) substitution on Zr{sup 4+} sites in BaZrO{sub 3} lead to band gap narrowing. > RE substitution lead to enhanced blue-green intrinsic emission of nanocrystalline BaZrO{sub 3} > Blue-green hue of BaZrO3:RE depends on RE dopant and excitation UV wavelength > BaZrO3: Dy{sup 3+} PL chromatic coordinates correspond to pure white color coordinates of CIE 1931 model - Abstract: The wet synthesis hydrothermal method at 100 deg. C was used to elaborate barium zirconate (BaZrO{sub 3}) unpurified with 0.5 mol% of different rare earth ions (RE = Yb, Er, Dy, Eu, Ce). Morphological, structural and UV-photoluminescence properties depend on the substituted rare earth ionic radii. While the crystalline structure of RE doped BaZrO{sub 3} remains as a cubic perovskite for all substituted RE ions, its band gap changes between 4.65 and 4.93 eV. Under 267 nm excitation the intrinsic green photoluminescence of the as synthesized BaZrO{sub 3}: RE samples is considerably improved by the substitution on RE ions. For 1000 deg. C annealed samples, under 267 nm, the photoluminescence is dominated by the intrinsic BZO emission. It is interesting to notice that Dy{sup 3+}, Er{sup 3+} and Yb{sup 3+} doped samples present whitish emissions that might be useful for white light generation under 267 nm excitation. CIE color coordinates are reported for all samples.

Morphology and luminescence characteristics of combustion synthesized Y{sub 2}O{sub 3}: (Eu, Dy, Tb) nanoparticles with various amino-acid fuels

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, S.; Sudarsan, V. [Chemistry Division Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Sastry, P.U.; Patra, A.K. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Tyagi, A.K., E-mail: aktyagi@barc.gov.in [Chemistry Division Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2014-01-15

Y{sub 2}O{sub 3} nanoparticles doped with Dy{sup 3+}, Eu{sup 3+} and Tb{sup 3+} together were prepared by the gel combustion method using a variety of amino acids namely, glycine, phenyl alanine, arginine, glutamic and aspartic acids. Number of carboxylate groups present in the amino acids used for combustion reaction was found to have strong influence on powder characteristics as well as luminescence from the samples. Based on small angle X-ray scattering studies, it is inferred that the nanoparticles prepared by using glycine and arginine as the fuels have smooth surface compared to those prepared using other amino acids. For the nanoparticles prepared using glutamic and aspartic acids, there exist a diffused pore-grain interface due to the lesser extent of heat generated in the reaction which leads to smaller particle size, poor crystallinity and improper burning of the organic materials. Lower surface area and smooth surface of the nanoparticles prepared using glycine leads to their improved luminescence properties. -- Highlights: • Surface smoothness of Y{sub 2}O{sub 3} (Dy, Eu, Tb) nanoparticles vary with amino acids. • Optimum luminescence intensity is observed when glycine is used as the fuel. • Diffused pore grain interface when glutamic and aspartic acids are used as fuels.

Structure, photo- and triboluminescence of the lanthanoid dibenzoylmethanates: HNEt3[Ln(dbm)4

International Nuclear Information System (INIS)

Akerboom, Sebastiaan; Meijer, Michael S.; Siegler, Maxime A.; Fu, Wen Tian; Bouwman, Elisabeth

2014-01-01

A series of lanthanoid coordination compounds with the general formula HNEt 3 [Ln(dbm) 4 ] (Ln=La, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb; dbm=dibenzoylmethanate) has been prepared and characterized. In addition, single crystals with Ln=La, Nd and Sm were obtained. Single crystal X-ray diffraction studies reveal that the compounds with Ln=La and Nd crystallize in the P2 1 /c space group, while the Sm-compound crystallizes in the Pc space group. Based on powder XRD data, the compounds with Ln=Eu–Yb can be described with a monoclinic cell. Photoluminescence studies indicate that compounds with Ln=Sm and Eu exhibit bright photoluminescence characteristic of the lanthanoid ion upon excitation in the near UV range. Furthermore, HNEt 3 [Sm(dbm) 4 ] has been identified as a novel triboluminescent compound. -- Highlights: • The compounds HNEt 3 [Ln(dbm) 4 ], Ln=La, Nd, Sm, Eu, Tb, Dy, Ho Er, Tm, and Yb, have been prepared and their photophysical properties have been studied. • Crystal structures of HNEt 3 [La(dbm) 4 ], HNEt 3 [Nd(dbm) 4 ] and HNEt 3 [Sm(dbm) 4 ] are reported for the first time. • A novel, brightly triboluminescent Sm compound is reported

Completing the series. New coordination networks of composition {sup 3}{sub ∞}[RE{sub 2}(ADC){sub 3}(H{sub 2}O){sub 6}].2H{sub 2}O with RE = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Y and ADC{sup 2-} = acetylenedicarboxylate ({sup -}O{sub 2}C-C≡C-CO{sub 2}{sup -})

Energy Technology Data Exchange (ETDEWEB)

Gramm, Verena K.; Schuy, Andrea; Ruschewitz, Uwe [Institut fuer Anorganische Chemie, Koeln Univ. (Germany); Suta, Markus; Wickleder, Claudia [Anorganische Chemie, Universitaet Siegen (Germany); Sternemann, Christian [Fakultaet Physik / DELTA, Technische Universitaet Dortmund (Germany)

2018-02-01

The crystal structures of {sup 3}{sub ∞}[RE{sub 2}(ADC){sub 3}(H{sub 2}O){sub 6}].2H{sub 2}O (RE = Pr, Nd, Sm, Eu, Tb, Dy) were solved and refined from X-ray single crystal data. They crystallize in a structure type already known for RE = La, Ce and Gd (P1, no. 2, Z = 2), which is characterized by REO{sub 9} polyhedra forming dimeric units being the nodes of a 3D framework structure linked by ADC{sup 2-} anions ({sup -}O{sub 2}C-C≡C-CO{sub 2}{sup -} = acetylenedicarboxylate). From synchrotron powder diffraction data it was shown that isostructural coordination networks are formed for RE = Ho, Er, Y, whereas for RE = Tm, Yb, Lu a new structure type crystallizing in a highly complex crystal structure with a large orthorhombic unit cell is found. All compounds are obtained by slow evaporation of an aqueous solution containing RE(OAc){sub 3}.xH{sub 2}O and acetylenedicarboxylic acid (H{sub 2}ADC). The coordination networks of composition {sup 3}{sub ∞}[RE{sub 2}(ADC){sub 3}(H{sub 2}O){sub 6}].2H{sub 2}O were thoroughly investigated by thermal analysis and for RE = Eu, Tb, a strong red and green photoluminescence was observed and investigated by means of UV/Vis spectroscopy. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis, luminescence, and energy-transfer properties of β-Na2Ca4(PO4)2(SiO4):A (A = Eu(2+), Dy(3+), Ce(3+)/Tb(3+)) phosphors.

Science.gov (United States)

Li, Kai; Shang, Mengmeng; Geng, Dongling; Lian, Hongzhou; Zhang, Yang; Fan, Jian; Lin, Jun

2014-07-07

A series of β-Na2Ca4(PO4)2(SiO4) (β-NCPS):A (A = Eu(2+), Dy(3+), Ce(3+)/Tb(3+)) phosphors were prepared via a high-temperature solid-state reaction route. The X-ray diffraction, Fourier transform infrared, photoluminescence (PL), cathodoluminescence (CL) properties, fluorescent lifetimes, and absolute quantum yield were exploited to characterize the samples. Under UV radiation, the β-NCPS:Eu(2+) phosphors present bright green emissions, and the β-NCPS:Ce(3+) phosphors show strong blue emissions, which are attributed to their 4f(6)5d(1) → 4f(7) and 5d-4f allowed transitions, respectively. The β-NCPS:Ce(3+), Tb(3+) phosphors display intense tunable color from blue to green and high absolute quantum yields (81% for β-NCPS:0.12Ce(3+) and 83% for β-NCPS:0.12Ce(3+), 0.08Tb(3+)) when excited at 365 nm. Simultaneously, the energy transfer from Ce(3+) to Tb(3+) ions is deduced from the spectral overlap between Ce(3+) emission and Tb(3+) excitation spectra and demonstrated by the change of emission spectra and decay lifetimes. Moreover, the energy-transfer mechanism from Ce(3+) to Tb(3+) ions is confirmed to be exchange interaction according to the discussion of expression from Dexter and Reisfeld. Under a low-voltage electron-beam excitation, the β-NCPS:A (A = Eu(2+), Dy(3+), Ce(3+)/Tb(3+)) phosphors exhibit their characteristic emissions, and the emission profiles of β-NCPS:Ce(3+),Tb(3+) phosphors are obviously different from those of the PL spectra; this difference might be ascribed to their different luminescence mechanisms. These results in PL and CL properties suggest that β-NCPS:A (A = Eu(2+), Dy(3+), Ce(3+)/Tb(3+)) phosphors are potential candidates for solid-state lighting and field-emission displays.

Color-tunable and white luminescence properties via energy transfer in single-phase KNaCa2(PO4)2:A (A = Ce3+, Eu2+, Tb3+, Mn2+, Sm3+) phosphors.

Science.gov (United States)

Geng, Dongling; Shang, Mengmeng; Zhang, Yang; Lian, Hongzhou; Lin, Jun

2013-12-02

A series of single-phase phosphors based on KNaCa2(PO4)2 (KNCP):A (A = Ce(3+), Eu(2+), Tb(3+), Mn(2+), Sm(3+)) have been prepared via the Pechini-type sol-gel method. Photoluminescence (PL) and cathodoluminescence (CL) properties of Ce(3+)-, Eu(2+)-, Tb(3+)-, Mn(2+)-, and Sm(3+)-activated KNCP phosphors were investigated. For the A singly doped KNCP samples, they exhibit the characteristic emissions of the A activator. Na(+) ions exhibit the best charge compensation result among Li(+), Na(+), and K(+) ions for Ce(3+)-, Tb(3+)-, and Sm(3+)-doped KNCP samples. The energy transfers from Ce(3+) to Tb(3+) and Mn(2+) ions as well as Eu(2+) to Tb(3+) and Mn(2+) have been validated. The emission colors of KNCP:Ce(3+)/Eu(2+), Tb(3+)/Mn(2+), Na(+) samples can be adjusted by energy transfer process and changing the Tb(3+)/Mn(2+) concentration. More importantly, white light emission in KNCP:Eu(2+), Mn(2+) system has been obtained. The KNCP:Tb(3+), Na(+) sample shows tunable luminescence from blue to cyan and then to green with the change of Tb(3+) concentration due to the cross-relaxation from (5)D3 to (5)D4. A white emission can also be realized in the single-phase KNCP host by reasonably adjusting the doping concentrations of Tb(3+) and Sm(3+) (reddish-orange emission) under low-voltage electron beam excitation. Additionally, the temperature-dependent PL properties of as-prepared phosphors reveal that the KNCP host has good thermal stability. Therefore, the KNCP:A (A = Ce(3+), Eu(2+), Tb(3+), Mn(2+), Sm(3+)) phosphors could be regarded as good candidates for UV W-LEDs and FEDs.

Photoluminescence of trivalent rare earths in perovskite stacking polytypes Ba/sub 2/Lasub(2-x)REsub(x)/sup 3 +/MgW/sub 2/vacantO/sub 12/, Ba/sub 6/Ysub(2-x)REsub(x)/sup 3 +/W/sub 3/vacantO/sub 18/, and Sr/sub 8/SrGdsub(2-x)REsub(x)/sup 3 +/W/sub 4/vacantO/sub 24/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1981-12-01

Rhombohedral 12 L staking polytypes Ba/sub 2/Lasub(2-x)REsub(x)/sup 3 +/MgW/sub 2/vacantO/sub 12/ show with RE/sup 3 +/ = Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm; the 18 L stacking polytypes Ba/sub 6/Ysub(2-x)REsub(x)/sup 3 +/W/sub 3/vacantO/sub 18/ and the polymorphic perovskites Sr/sub 8/SrGdsub(2-x)REsub(x)/sup 3 +/W/sub 4/vacantO/sub 24/ with RE/sup 3 +/ = Sm, Eu, Dy, Ho, Er visible photoluminescence. The concentration dependence and the influence of the coordination number of the rare earth are reported.

Structural characterization and optical properties of Eu"2"+ and Dy"2"+ doped Sr_2SiO_4 phosphor by solid state reaction method

International Nuclear Information System (INIS)

Verma, Durga; Verma, Mohan L.; Upma; Patel, R.P.

2016-01-01

Thermoluminescence, SEM, FTIR Divalent dysprosium and europium doped strontium silicate (Sr_2SiO_4) phosphors were synthesized with the high-temperature solid-state reaction technique. The obtained phosphor was well characterized by powder X-ray diffraction, scanning electron microscopy, FTIR, UV-visible spectroscopy and thermoluminescence. The crystal structure of the prepared phosphor has an orthorhombic structure with space group Pnma. From scanning electron microscopy (SEM), agglomerations of particles were observed due to the high temperature synthesis process. The chemical composition of the sintered Sr_2SiO_4:Dy"2"+ and Sr_2SiO_4: Eu"2"+ phosphor was confirmed by energy dispersive X-ray spectroscopy (EDX). The UV-VIS analysis can be thought as a good quality check for the optical behavior of materials. The Fourier transmission infrared spectroscopy (FTIR) confirms the present elements in phosphor. Thermoluminescence study was carried out for the phosphor with UV irradiation show one glow peak. The trapping parameters associated with the prominent glow peak of Sr_2SiO_4:Dy"2"+ and Sr_2SiO_4:Eu"2"+ are calculated using Chen's glow curve method. The release of holes/electrons from defect centers at the characteristic trap site initiates the luminescence process in this material. (author)

Spin-glass-like behaviour in IrSr2RECu2O8 (RE=Sm and Eu)

International Nuclear Information System (INIS)

Santos-Garcia, A.J. dos; Duijn, J. van; Alario-Franco, M.A.

2008-01-01

We report the results of magnetic and specific heat measurements on the 1212-type compounds IrSr 2 RECu 2 O 8 with RE=Sm and Eu, prepared by high-pressure and high-temperature synthesis. The magnetic susceptibility of these compounds shows a large difference in the temperature dependence of the magnetization measured under zero-field-cooled and field-cooled conditions below 87 and 71 K, respectively, and upon further cooling below ∼10 K substantial maxima are observed too. Further AC susceptibility measurements support a glassy behaviour in lower magnetic transitions whereas the specific heat measurements do not show the typical long-range ordering commonly displayed in ferro, ferri or antiferromagnetic transitions. Hysteresis loops suggest the presence of magnetic clusters in the otherwise paramagnetic zone, indicating that these compounds probably display a reentrant spin-glass transition. Results are presented and discussed. - Graphical abstract: IrSr 2 RECu 2 O 8 with RE=Sm and Eu were prepared by high-pressure and high-temperature synthesis. Both samples adopt a M-1212-type perovskite structure and a microdomain texturing of the long c-axis is observed by TEM. A very interesting magnetic behaviour is observed in these materials. A 'cluster by cluster freezing' model is proposed, instead of the classical individual spin freezing one to explain the spin-glass-like behaviour that seems to coexist with weak ferromagnetism in both compounds

Investigation of Sm(3) and Eu(3) coordination compounds with pyrazolones by IR spectroscopy method

International Nuclear Information System (INIS)

Panyushkin, V.T.; Grishenko, T.V.; Afanas'ev, Yu.A.; Garnovskij, A.D.; Osipov, O.A.

1978-01-01

The synthesis is described of the coordination nitrate compounds of Sm(3) and Eu(3) with pyrazolones: 4-aminoantipyrine (A), 1-ethylpyridyl- 3-phenyl-pyrazolone-5(B); 1-(3'-ethylpyridyl)-3(phenylamine-n)-pyrazolone-5(C). It has been determined by the infrared spectroscopy method that exocyclic oxygen atom is the place of coordination bond localization in the pentioned compounds. The infrared spectra analysis of complexes in the 1700-1800 cm -1 region makes it possible to mention bidentate character of NO 3 -groups in the studied complex compounds

Synthesis and characterization of BaAl{sub 2}O{sub 4}:Eu{sup 2+} co-doped with different rare earth ions

Energy Technology Data Exchange (ETDEWEB)

Lephoto, M.A. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Ntwaeaborwa, O.M., E-mail: ntwaeab@ufs.ac.za [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Pitale, Shreyas S.; Swart, H.C. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth, ZA 6031 (South Africa); Mothudi, B.M. [Department of Physics, University of South Africa, P.O Box 392, Pretoria, ZA 6031 (South Africa)

2012-05-15

Combustion method was used in this study to prepare BaAl{sub 2}O{sub 4}:Eu{sup 2+} phosphors co-doped with different trivalent rare-earths (Re{sup 3+}=Dy{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Sm{sup 3+}, Ce{sup 3+}, Er{sup 3+}, Pr{sup 3+} and Tb{sup 3+}) ions at an initiating temperature of 600 Degree-Sign C. The phosphors were annealed at 1000 Degree-Sign C for 3 h. As confirmed from the X-ray diffraction (XRD) data, both as prepared and post annealed samples crystallized in the well known hexagonal structure of BaAl{sub 2}O{sub 4}. All samples exhibited bluish-green emission associated with the 4f{sup 6}5d{sup 1}{yields}4f{sup 7} transitions of Eu{sup 2+} at {approx}500 nm. Although the highest intensity was observed from Er{sup 3+} co-doping, the longest afterglow (due to trapping and detrapping of charge carriers) was observed from Nd{sup 3+} followed by Dy{sup 3+} co-doping. The traps responsible for the long afterglow were studied using thermoluminescence (TL) spectroscopy.

Multifunctional Sm2-xDyxZr2O7 pyrochlore system: potential ionic conductors and photocatalysts

International Nuclear Information System (INIS)

Grover, V.; Sayed, Farheen N.; Bhattacharyya, K.; Jain, D.; Pillai, C.G.S.; Tyagi, A.K.; Arya, A.

2010-01-01

Full text: Pyrochlores have garnered considerable interest over the years because of a range of potentially useful properties such as fast-ion (mainly anion) conductivity, electrical conductivity, catalysis, luminescence etc. In present work a series of Sm 2-x Dy x Zr 2 O 7 compounds (0.0 ≤ x ≤ 2.0) were synthesized by gel combustion and characterized by Powder XRD and Raman spectroscopic studies. XRD studies revealed the system to be single-phasic throughout with the retention of pyrochlore phase till 40 mol% of Dy 3+ beyond which, an order-disorder phase transition occurred resulting in a defect fluorite structure. Surprisingly, Raman studies showed the retention of pyrochlore type ordering till the other end member, i.e. Dy 2 Zr 2 O 7 . This is the first study, which reports the retention of a weak pyrochlore type superstructure in Dy 2 Zr 2 O 7 system. Ionic conductivity measurements were performed on these samples, which showed that the activation Energy (E a ) increases with increase in Dy 3+ mol% owing to the decreased mobility with increasing degree of disorder. The representative nquist Plots are given for Sm 2 Zr 2 O 7 . These materials have a definite band gap absorbing mainly in the UV region which makes them good candidates for photocatalysed dye degradation studies. Potential of some of these compositions as photocatalysts was also explored and they were found to efficiently catalyse the degradation of Xylenol Orange with t 1/2 decreasing from pure Sm 2 Zr 2 O 7 to pure Dy 2 Zr 2 O 7

A novel fluorescent probe (dtpa-bis(cytosine)) for detection of Eu(III) in rare earth metal ions

Science.gov (United States)

Yang, Fan; Ren, Peipei; Liu, Guanhong; Song, Youtao; Bu, Naishun; Wang, Jun

2018-03-01

In this paper, a novel fluorescent probe, dtpa-bis(cytosine), was designed and synthesized for detecting europium (Eu3 +) ion. Upon addition of Eu3 + ions into the dtpa-bis(cytosine) solution, the fluorescence intensity can strongly be enhanced. Conversely, adding other rare earth metal ions, such as Y3 +, Ce3 +, Pr3 +, Nd3 +, Sm3 +, Gd3 +, Tb3 +, Dy3 +, Ho3 +, Er3 +, Yb3 + and Lu3 +, into dtpa-bis(cytosine) solution, the fluorescence intensity is decreased slightly. Some parameters affecting the fluorescence intensity of dtpa-bis(cytosine) solution in the presence of Eu3 + ions were investigated, including solution pH value, Eu3 + ion concentration and interfering substances. The detection mechanism of Eu3 + ion using dtpa-bis(cytosine) as fluorescent probe was proposed. Under optimum conditions, the fluorescence emission intensities of EuIII-dtpa-bis(cytosine) at 375 nm in the concentration range of 0.50 × 10- 5 mol • L- 1-5.00 × 10- 5 mol • L- 1 of Eu3 + ion display a better linear relationship. The limit of detection (LOD) was determined as 8.65 × 10- 7 mol • L- 1 and the corresponding correlation coefficient (R2) of the linear equation is 0.9807. It is wished that the proposed method could be applied for sensitively and selectively detecting Eu3 + ion.

Persistent luminescence of Eu, Mn, Dy doped calcium phosphates for in-vivo optical imaging

Energy Technology Data Exchange (ETDEWEB)

Rosticher, Céline [UPMC Univ Paris 06, CNRS, UMR 7574, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05 (France); Viana, Bruno, E-mail: bruno.viana@chimie-paristech.fr [PSL Research University, Chimie ParisTech-CNRS, Institut de Recherche de Chimie Paris, 11 rue Pierre et Marie Curie, 75005 Paris (France); Maldiney, Thomas; Richard, Cyrille [Unité de Technologies Chimiques et Biologiques pour la Santé, CNRS, UMR 8258, Paris Cedex F-75270 (France); Inserm U1022, Paris Cedex F-75270 (France); Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, Sorbonne Paris Cité, Paris Cedex F-75270 (France); Chanéac, Corinne, E-mail: corinne.chaneac@upmc.fr [UPMC Univ Paris 06, CNRS, UMR 7574, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05 (France)

2016-02-15

Biocompatible nanoparticles possessing persistent luminescence properties offer attractive possibilities for in vivo imaging applications as it allows an excitation of the sensors outside the animal before injection and a long-lasting emission of light. Here we report the development of highly biocompatible calcium phosphate nanoparticles doped with europium, Mn{sup 2+} and Ln{sup 3+} (Ln{sup 3+}=Dy{sup 3+}, Pr{sup 3+}) ions synthesized by hydrothermal route and tailored to present red-near infrared persistent luminescence after UV excitation. Nanosize biphasic HAp/β-TCP compounds with sphere and rod-shaped were obtained. Two emission bands in the red-near infrared range were observed and attributed to {sup 4}T{sub 1}→{sup 6}A{sub 1} transitions of Mn{sup 2+} ions in HAp/β-TCP. An annealing treatment in reductive atmosphere post-synthesis was essential to reveal persistent luminescence properties. Indeed, such thermal treatment allows reducing Eu{sup 3+} ions in Eu{sup 2+} ions and generating required defaults as oxygen vacancies in the crystal necessary for red emission in accordance with persistent luminescence mechanism. These nanoparticles have been tested for the first time for in vivo imaging on small animal as proof of concept of prospective highly biocompatible nanoprobes. - Highlights: • Biocompatible HAp/b-TCP nanoparticles with persistent luminescence are investigated. • Reducing step induced persistent luminescence. • Nanoparticles have been tested for the first time for in vivo imaging. • Persistent luminescence is observed after 10 min in vivo.

Determination of lanthanides in rare earths concentrates by emission optical spectrography

International Nuclear Information System (INIS)

Friedmann, R.; Lordello, A.R.; Abrao, A.

1978-01-01

A spectrochemical method has been developed for the determination of Y, Pr, Sm, Eu, Gd and Dy in purified lanthanum oxide; Y, La, Nd, Sm, Gd and Dy in purified cerium oxide and Y, La, Sm, Eu, Gd and Dy in purified neodymium oxide. The technique consists of an almost total consumption of the sample in a 17 ampere direct current arc. The rare earth oxides are mixed with an equal amount by weight of spectrographic graphite and the electrodes are arced in an argon (80%)-oxygen (20%) atmosphere, inside a specially desingned chamber, to suppress cyanogen bands. The concentration ranges are approximatelly 0.002 - 2%, depending on the matrix and the elements to be analysed. The presicion, accuracy and acceptability of the method are calculated for all elements. The total error values are approximately in the range of 18-48%. The method was developed for quality control of the individual fractions held by pulsed and ion exchange columns in the lanthanide separations, in the Chemical Engineering Centre, Atomic Energy Institute, Sao Paulo [pt

Control of rare earths fractioning in a pilot unit, by emission optical spectrography

International Nuclear Information System (INIS)

Friedmann, R.

1978-01-01

A spectrochemical method has been developed for the determination of Y, Pr, Sm, Eu, Gd and Dy in purified lanthanum oxide; Y, La, Nd, Sm, Gd and Dy in purified cerium oxide and Y, La, Sm, Eu, Gd and Dy in neodymium oxide. The technique consists of an almost total consumption of the sample in a 17 amperes direct current arc. The rare erath oxides are mixed with an equal amount by weight of spectrographic graphite powder and the electrodes are arced in an argon(80%)-oxygen (20%) atmosphere, inside a specially designed chamber, to suppress cyanogen bands. The concentration ranges are approximately 0.002-2%, depending on the matrix and the elements to be analysed. The precision, accuracy and acceptability of the method are calculated for all elements. The total error values are approximately in the range of 18-48%. The method was developed for the quality control of the individual fractions held by pulsed and ion exchange columns in the lanthanide separations, in the Centro de Engenharia Quimica, Instituto de Energia Atomica, Sao Paulo [pt

Synthesis and luminescent spectroscopy of lanthanide complexes with dimethylpyridine-2,6-dicarboxylate (dmpc)

Energy Technology Data Exchange (ETDEWEB)

Taha, Ziyad A., E-mail: tahaz33@just.edu.jo [Department of Applied Chemical Sciences, Faculty of Arts and Sciences, Jordan University of Science and Technology, Irbid 22110 (Jordan); Ajlouni, Abdulaziz M.; Hijazi, Ahmed K. [Department of Applied Chemical Sciences, Faculty of Arts and Sciences, Jordan University of Science and Technology, Irbid 22110 (Jordan); Al-Rawashdeh, Nathir A. [Department of Applied Chemical Sciences, Faculty of Arts and Sciences, Jordan University of Science and Technology, Irbid 22110 (Jordan); Department of Chemistry, United Arab Emirates University, Al Ain 15551 (United Arab Emirates); Al-Hassan, Khader A.; Al-Haj, Yaser A. [Department of Chemistry, Faculty of Science, Yarmouk University, 1163 Irbid (Jordan); Ebqa' ai, Mohammad A. [Al-Qunfudah Center For Scientific Research, Umm Al-Qura University, College in Al-Qunfudah, Makkah (Saudi Arabia); Altalafha, Ammar Y. [Department of Chemistry, Faculty of Science, Yarmouk University, 1163 Irbid (Jordan)

2015-05-15

A series of lanthanide complexes with the general formulae [Ln(dmpc)(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}]NO{sub 3} (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er) and [La(dmpc)(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}]NO{sub 3} were prepared by direct reaction between hydrated lanthanide(III) nitrate and dimethylpyridine-2,6-dicarboxylate (dmpc) in a 1:1 M ratio in ethylacetate–chloroform mixture. The luminescence properties of the dmpc and its Ln(III) complexes were investigated in solid state and in methanol, DMF and DMSO solutions. The Tb–dmpc, Eu–dmpc, Sm–dmpc and Dy–dmpc complexes exhibit characteristic luminescence of Tb(III), Eu(III), Sm(III) and Dy(III) ions indicating energy transfer from the dmpc to the Ln(III) ions. Scavenging activities of the dmpc and its Ln(III) complexes on DPPH{sup •} free radical were investigated in DMSO solution at a different concentrations ranges. - Highlights: • Nine new lanthanide complexes with dmpc ligand are prepared and characterized. • Ln–dmpc {Ln=Eu, Tb, Sm, Dy} complexes exhibit characteristic emissions of Ln ions. • The solvent effect on the luminescence intensity is investigated. • The antioxidant activity of the dmpc is enhanced upon complexation with lanthanide.

Magnetization fluctuation analysis and superconducting parameters of La0.5RE0.5BaCaCu3O7-δ(RE=Y, Sm, Gd, Dy, Ho, Yb) superconductor

International Nuclear Information System (INIS)

Parra Vargas, C.A.; Pimentel, J.L.; Pureur, P.; Landinez Tellez, D.A.; Roa-Rojas, J.

2009-01-01

In this work we report the analysis of magnetization experimental data of the La 0.5 RE 0.5 BaCaCu 3 O 7-δ (RE=Y, Sm, Gd, Dy, Ho, Yb) superconducting system. The data are analyzed in terms of thermal fluctuations on the magnetization excess ΔM(T) for different values of temperature in each one of the samples. We describe a procedure for extracting the penetration depth λ ab (∼1571A) and the coherence length ξ ab (∼1.52A) parameters from the magnetization, as a function of the applied magnetic field. This procedure was performed for polycrystalline samples of La 0.5 RE 0.5 BaCaCu 3 O 7-δ by using the theory of Bulaevskii, Ledvij and Kogan, which analyzes the vortex fluctuation in superconducting materials within the Lawrence-Doniach framework. These data allowed to determine the characteristic temperature value T * (73, 58, 48, 57, 56, 71 K, for RE=Y, Sm, Gd, Dy, Ho, Yb, respectively) in the magnetization curves for several magnetic fields. We calculated the data of magnetization excess from the curves of magnetization as a function of logarithm of applied field. We notice that the values for these superconducting parameters are in agreement with the reports for high temperature superconductors. The obtained value of superconducting volumetric fraction is compared with that obtained through the measure of the Meissner effect.

Fabrication and characterization of SrAl{sub 2}O{sub 4}: Eu{sup 2+} Dy{sup 3+}/CS-PCL electrospun nanocomposite scaffold for retinal tissue regeneration

Energy Technology Data Exchange (ETDEWEB)

Sepahvandi, Azadeh; Eskandari, Mahnaz, E-mail: eskandarim@aut.ac.ir; Moztarzadeh, Fathollah

2016-09-01

Millions of people around the world become blind due to losing a part of the retina cells. In tissue engineering field one way to address this issue is to develop a retina tissue by scaffolds based on structure and signals received These scaffolds can play an essential role in repair and reformation of the damaged retina tissue. Here, SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+} nanophosphor were prepared by sol-gel method and then coated with PEG to become biocompatible. Next 10%, 30% and 50% concentration of the coated nanophosphors were dispersed in CS-PCL copolymer and electrospuned to form SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+}/CS-PCL scaffolds. The aforementioned photo –luminescence-scaffolds were studied for their optical, mechanical and morphological characteristics finally the effect of these scaffolds on the mice RPCs cells' proliferation and differentiation was observed. The 30% nanophosphor dispersion scaffold while providing adequate mechanical flexibility and integrity, and exhibiting superior proliferation rates and acceptable differentiation into retinal neural cells (particularly photo receptors retinal) is suggested as a promising choice in retinal tissue repair. - Highlights: • The 30% nanophosphor dispersion scaffold for both shorter wavelength and middle intense emission is more near to biocompatible nanophosphors. • 30% dispersed nanophosphor scaffold displays satisfactory mechanical strength and flexibility where its behavior is similar to the retina tissue. • Besides as the most effective signal in this study is the electromagnetic signals emitted by nanophosphors, we attribute the enhanced proliferation to the positive effects of the later, the emitted signals of scaffolds. • The tendency towards spherical morphology implies that emitting light may stimulate the cell signaling toward differentiation • These findings implies that mRPC grown on SrAl{sub 2}O{sub 4}: Eu{sup 2+},Dy{sup 3+}/CS-PCL scaffolds in differentiation

Energy spectrum of CsDy(MoO/sub 4/)/sub 2/ in the vicinity of the structural phase transition

Energy Technology Data Exchange (ETDEWEB)

Khats' ko, E N; Chernyj, A S [AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur

1981-08-01

The magnetic susceptibilities of CsDy(MoO/sub 4/)/sub 2/ and CsDy(MoO/sub 4/)/sub 2/+10%Eu/sup 3 +/ were measured in the temperature range 4 to 70 K and the frequency range 200 Hz to 20 MHz. The observed spin-lattice relaxation of the Dy/sup 3 +/ ion is found to be exponential with the relaxation time as a function of temperature tau/sup -1/=A exp (-..delta../kT) with ..delta..=105+-20 and 250+-40 cm/sup -1/ for CsDy(MoO/sub 4/)/sub 2/ in ranges 10-20 K and 20-38 K, respectively, and ..delta..=22.4+-5 cm for C=sDy(MoO/sub 4/)/sub 2/+10%Eu/sup 3 +/. The energies ..delta..105+-20 and 250 -40cm/sup -1/ are suggested to correspond to the first and second excited levels of Dy/sup 3 +/ in the low temperature phase of CsDy(MoO/sub 4/)/sub 2/, and ..delta..=22.4+-5 cm/sup -1/ to the first excited level of Dy/sup 3 +/ in the high temperature phase of the compound.

Synthesis and thermoluminescence of new Li{sub 2}SO{sub 4}:Eu and Li{sub 2}SO{sub 4}:Dy phosphors exposed to beta radiation

Energy Technology Data Exchange (ETDEWEB)

Garcia H, A. R.; Bustamante L, G. A.; Castro C, A. I. [Universidad de Sonora, Departamento de Ciencias Quimico Biologicas, 83000 Hermosillo, Sonora (Mexico); Bernal H, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Cruz V, C.; Burruel I, S. E. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Castano M, V. M., E-mail: argh@gimmunison.com [UNAM, Instituto de Fisica, Departamento de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

2015-10-15

Full text: Li{sub 2}SO{sub 4} is systematically studied for the very first concerning their dosimetric capabilities. Pellet- shaped Eu and Dy doped Li{sub 2}SO{sub 4} phosphors were synthesized by sintering. Some samples were exposed to beta particle irradiation in order to investigate their thermoluminescence (Tl) features. Glow curves were obtained for 80 mg mass samples, showing that both, Tl sensitivity as well as the temperature at which the Tl maximum is recorded, depends upon the sample dopant. The glow curves of Li{sub 2}SO{sub 4}:Eu exhibit two maxima, located at 433 and 573 K, when a 5 K/s heating rate was used, being the most intense emission that observed at 573 K. The integrated Tl increases as the radiation dose was increased in the 0.25 - 5 Gy range, with no shift of the Tl maxima being observed, meaning that first order kinetics processes are involved in the Tl emission. The normalized sensitivity recorded in ten consecutive irradiation-Tl readout cycles shows a good reusability with only 5 % variability. The integrated Tl fades as a function of the elapsed time between irradiation and the corresponding Tl readout of Eu and Dy doped Li{sub 2}SO{sub 4} phosphors is obtained. From the obtained results, we conclude that Li{sub 2}SO{sub 4} is a promising phosphor material to develop high performance Tl dosimeters, and a long term research work focused to understand and to improve their Tl features is absolutely justified. (Author)

The effect of different gas atmospheres on luminescent properties of pulsed laser ablated SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+} thinfilms

Energy Technology Data Exchange (ETDEWEB)

Nsimama, P.D. [Physics Department, University of the Free State, P. O. Box 9300, Bloemfontein (South Africa); Department of Laboratory Technology, Dar Es Salaam Institute of Technology, P. O. Box 2958, Dar Es Salaam, Tanzania (Tanzania, United Republic of); Ntwaeaborwa, O.M. [Physics Department, University of the Free State, P. O. Box 9300, Bloemfontein (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.z [Physics Department, University of the Free State, P. O. Box 9300, Bloemfontein (South Africa)

2011-01-15

SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+} thin films were grown on Si (1 0 0) substrates using the pulsed laser deposition (PLD) technique to investigate the effect of vacuum, oxygen (O{sub 2}) and argon (Ar) deposition atmospheres on the structural, morphological, photoluminescence (PL) and cathodoluminescence (CL) properties of the films. The films were ablated using a 248 nm KrF excimer laser. Atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and fluorescence spectrophotometry were used to characterize the thin films. Auger electron spectroscopy (AES) combined with CL spectroscopy were employed for the surface characterization and electron-beam induced degradation of the films. Better PL intensities were obtained from the unannealed films prepared in Ar and O{sub 2} atmospheres with respect to those prepared in vacuum. A stable green emission peak at 515 nm, attributed to 4f{sup 6}5d{sup 1{yields}}4f{sup 7} Eu{sup 2+} transitions were obtained with less intense peaks at 619 nm, which were attributed to transitions in Eu{sup 3+}. After annealing the films prepared in vacuum at 800 {sup o}C for 2 h, the intensity of the green emission (520 nm) of the thin film increased considerably. The amorphous thin film was crystalline after the annealing process. The CL intensity increased under prolonged electron bombardment during the removal of C due to electron stimulated surface chemical reactions (ESSCRs) on the surface of the SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} thin films. The CL stabilized and stayed constant thereafter.

Phase transition of the orthorhombic fluorite-related compounds Ln{sub 3}IrO{sub 7} (Ln = Pr, Nd, Sm, Eu)

Energy Technology Data Exchange (ETDEWEB)

Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.j [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Doi, Yoshihiro; Nishimine, Hiroaki; Wakeshima, Makoto [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Sato, Mineo [Department of Chemistry and Chemical Engineering, Faculty of Engineering, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan)

2009-12-04

Rare earth iridium oxides Ln{sub 3}IrO{sub 7} (Ln = Pr, Nd, Sm, and Eu) were prepared and their structures were determined by X-ray diffraction measurements. At room temperature, Pr{sub 3}IrO{sub 7} crystallized in an orthorhombic superstructure of cubic fluorite with space group Cmcm. The differential thermal analysis (DTA) and specific heat measurements for Ln{sub 3}IrO{sub 7} (Ln = Pr, Nd, Sm, and Eu) showed a phase transition at 262, 342, 420, and 485 K, respectively. At low temperatures, Ln{sub 3}IrO{sub 7} crystallized in a monoclinic structure with the space group P2{sub 1}/n. The transition temperatures increased with decreasing the ionic radius of rare earths, which indicates that the transition is stress-induced and occurs with the lattice contraction on cooling. These results for Ln{sub 3}IrO{sub 7} were compared with the phase transitions observed for Ln{sub 3}MoO{sub 7}, Ln{sub 3}RuO{sub 7}, Ln{sub 3}ReO{sub 7}, and Ln{sub 3}OsO{sub 7}.

Neutron activation analysis of NBS oyster tissue (SRM 1566) and IAEA animal bone (H-5)

International Nuclear Information System (INIS)

Lepel, E.A.; Laul, J.C.

1983-10-01

Data have been presented for 35 elements determined by INAA for NBS oyster tissue (SRM 1566) and for 38 elements determined by INAA and RNAA for IAEA animal bone (H-5). The experimental data showed excellent agreement with published values wherever the comparison exists. Additional trace-element data in the ppb range have been presented for the elements Sc, Sb, Cs, La, Ce, Nd, Sm, Eu, Tb, Dy, Ho, Yb, Lu, Hf, Ta, W and Th in NBS oyster tissue. Also, additional trace-element data for IAEA animal bone (H-5) in the ppb range for the elements Al, Sc, Co, Rb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, lu, Hf, Ta and Th have been presented

Elemental content in ground and soluble/instant coffee

International Nuclear Information System (INIS)

Vega-Carrillo, H.R.; Manzanares-Acuna, E.; Iskander, F.Y.

2002-01-01

The concentration of thirty-four elements in twelve coffee brands has been measured using instrumental neutron activation analysis. The samples investigated included four brands of commercially available ground coffee and eight brands of soluble/instant coffee. The elements measured were Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Gd, Hf, K, La, Lu, Mg, Mn, Na, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, Tm, U, V, Yb and Zn. Twenty four elements were found to be below the detection limit in one or more samples. These elements were Ce, Cr, Fe, V, As, Eu, Ba, Dy, Gd, Hf, La, Lu, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, Yb, Tm, and U. (author)

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.

Fabrication, magnetostriction properties and applications of Tb-Dy-Fe alloys: a review

Directory of Open Access Journals (Sweden)

Nai-juan Wang

2016-03-01

Full Text Available As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys (based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2 Laves compound can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there are two different ways to substitute for these alloying elements. One is to partially replace Tb or Dy by cheaper rare earth elements, such as Pr, Nd, Sm and Ho; and the other is to use non-rare earth elements, such as Co, Al, Mn, Si, Ce, B, Be and C, to substitute Fe to form single MgCu2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the alloy. This paper systemically introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe alloys. In addition, the effects of alloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe alloys are also reviewed, respectively. Finally, some possible applications of Tb-Dy-Fe alloys are presented.

Thermoluminescence of LaAlO3 crystals doped with Eu and Ce - Dy ions exposed to ultraviolet and gamma radiation

International Nuclear Information System (INIS)

Oliveira, Vitor H.; Faria, Luiz O.; Silva, Edna S.

2011-01-01

Due to environmental problems such as degradation of the ozone layer and control of radiation levels in units of radiation, new dosimetric materials with high sensitivity for ultraviolet (UV) and gamma radiation are of great interest for applications in environmental dosimetry. In this context, this paper presents the results of a systematic investigation of the thermoluminescent (TL) response of LaAlO 3 crystals doped with different concentrations of trivalent optically active ions exposed to UV and gamma radiation doses. The work has been performed under a direct cooperation between the Institute of Inorganic Chemistry in Moscow (IGIC), responsible for crystal growth, and the Center for Development of Nuclear Technology (CDTN), responsible for the study of its luminescent properties. In this context, samples doped with 1% of Eu 3+ , 1% Ce 3+ , 5% of Ce 3+ and also co-doped with 5% Ce 3+ and 1% Dy 3+ were grown under hydrothermal conditions. The investigation was divided into two fronts, one for gamma radiation and the other for UV radiation. In the investigation with gamma radiation the best TL response has been obtained from LaAlO 3 :Eu. This crystal has shown good sensitivity and excellent linearity between TL output and the delivered gamma doses ranging from 0.1 to 10.0 mGy. In addition, its TL curve is quite similar to the Al 2 O 3 :C, a commercial TL phosphor with high sensitivity to gamma radiation. In the investigation with UV radiation the best response has been achieved for co-doped LaAlO 3 :Ce,Dy. They have excellent sensitivity and good linearity for spectral irradiances ranging from 0.042 to 1.2 mJ.cm -2 . (author)

152Eu decay

International Nuclear Information System (INIS)

Artamonova, K.P.; Vinogradov, V.M.; Grigor'ev, E.P.; Zolotavin, A.V.; Makarov, V.M.; Sergeev, V.O.; Usynko, T.M.

1978-01-01

The purpose of this paper is the measurement of the relative intensities of the most intensive conversion lines of 152 Eu, the determination of as reliable as possible magnitudes of the intensities of γ-quanta using all the available data on γ-radiation of 152 Eu, the measurement of the interval conversion coefficients (ICC) for the most intensive γ-transitions, the determination of the probabilities of the 152 Eu β-decays to the 152 Sm and 152 Gd levels. The conversion lines of the most intensive γ-transitions in the 152 Eu decay are studied and the corresponding ICC are measured on the beta-spectrometers of π√2 and UMB type. The balance for the γ-transitions in the 152 Sm and 152 Gd daughter nuclei are presented. This balance is used to determine the absolute intensities of γ-rays (in terms of the percentage of the 152 Eu decays) and the probabilities of β-transitions to the levels of daughter nuclei. More accurate data on γ-rays and conversion electrons obtained can be used for the calibration of gamma and beta spectrometers

Distribution of stable traps for thermoluminescent processes in the phosphor SrAl2O4: Eu2+, Dy3+

International Nuclear Information System (INIS)

Pedroza M, M.; Castaneda, B.; Arellano T, O.; Melendrez, R.; Barboza F, M.

2007-01-01

Full text: The phosphor of persistent luminescence (PLUM) SrAl 2 O 4 :Eu 2+ , Dy 3+ exhibits one thermoluminescence curve after exposing it to UV radiation. The curve is made up of a wide band with a maximum around 455 K. Starting from the experimental deconvolution method proposed by McKeever, it was solved the number of peaks in the TL curve and it was analyzed the position of each TL peak regarding to the cut temperature (T stop ). In this analysis five maximum TL peaks were observed (at the diagram T stop vs T max ) around the 319, 425, 457, 488 and 515 K. Also, its were also found two regions that correspond to an overlap of stable traps, the first one in the region of the 380 K at 415 K and the second of the 430 to 455 K. The existence of a distribution of stable traps can be evaluated from the curve T stop vs T max where this distribution of stable traps is presented as a monotonous lineal increase with the temperature, because the TL independent processes appear like horizontal lines exactly in the specific temperatures (319, 425, 457, 488 and 515 K) where its are liberated most of the trapped charges. Using the preheating method and initial increase for the peak in 455 K the trap depths are determined, being obtained the following values of the activation energy 0.28, 0.67, 1, 1.5 and 1.62 eV. An arrangement of stable traps plays a decisive role in the emission of the persistent luminescence. Likewise, it was determined that all the thermoluminescent processes were characterized by a re trapping of the charge, reason by which these processes followed a second order kinetics. The TL peak of low temperature 319 K is related with those electronic traps that the PLUM takes place in SrAl 2 O 4 : Eu 2+ and with the same recombination centers. The PLUM emissions and the TL are centered around 510 nm attributed to the electronic transition 4f 6 5d 1 →4f 7 corresponding to the Eu 2+ ion. In this work, it is explained the participation or contribution of the

Thermoluminescence of LaAlO{sub 3} crystals doped with Eu and Ce - Dy ions exposed to ultraviolet and gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Vitor H.; Faria, Luiz O., E-mail: farialo@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Silva, Edna S. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Energia Nuclear; Khaidukov, Nicholas M. [Kurnakov Institute of General and Inorganic Chemistry, IGIC, Moscow (Russian Federation)

2011-07-01

Due to environmental problems such as degradation of the ozone layer and control of radiation levels in units of radiation, new dosimetric materials with high sensitivity for ultraviolet (UV) and gamma radiation are of great interest for applications in environmental dosimetry. In this context, this paper presents the results of a systematic investigation of the thermoluminescent (TL) response of LaAlO{sub 3} crystals doped with different concentrations of trivalent optically active ions exposed to UV and gamma radiation doses. The work has been performed under a direct cooperation between the Institute of Inorganic Chemistry in Moscow (IGIC), responsible for crystal growth, and the Center for Development of Nuclear Technology (CDTN), responsible for the study of its luminescent properties. In this context, samples doped with 1% of Eu{sup 3+}, 1% Ce{sup 3+}, 5% of Ce{sup 3+} and also co-doped with 5% Ce{sup 3+} and 1% Dy{sup 3+} were grown under hydrothermal conditions. The investigation was divided into two fronts, one for gamma radiation and the other for UV radiation. In the investigation with gamma radiation the best TL response has been obtained from LaAlO{sub 3}:Eu. This crystal has shown good sensitivity and excellent linearity between TL output and the delivered gamma doses ranging from 0.1 to 10.0 mGy. In addition, its TL curve is quite similar to the Al{sub 2}O{sub 3}:C, a commercial TL phosphor with high sensitivity to gamma radiation. In the investigation with UV radiation the best response has been achieved for co-doped LaAlO{sub 3}:Ce,Dy. They have excellent sensitivity and good linearity for spectral irradiances ranging from 0.042 to 1.2 mJ.cm{sup -2}. (author)

Luminescent Afterglow Behavior in the M2Si5N8: Eu Family (M = Ca, Sr, Ba

Directory of Open Access Journals (Sweden)

Koen Van den Eeckhout

2011-05-01

Full Text Available Persistent luminescent materials are able to emit light for hours after being excited. The majority of persistent phosphors emit in the blue or green region of the visible spectrum. Orange- or red-emitting phosphors, strongly desired for emergency signage and medical imaging, are scarce. We prepared the nitrido-silicates Ca2Si5N8:Eu (orange, Sr2Si5N8:Eu (reddish, Ba2Si5N8:Eu (yellowish orange, and their rare-earth codoped variants (R = Nd, Dy, Sm, Tm through a solid state reaction, and investigated their luminescence and afterglow properties. In this paper, we describe how the persistent luminescence is affected by the type of codopant and the choice and ratio of the starting products. All the materials exhibit some form of persistent luminescence, but for Sr2Si5N8:Eu,R this is very weak. In Ba2Si5N8:Eu the afterglow remains visible for about 400 s, and Ca2Si5N8:Eu,Tm shows the brightest and longest afterglow, lasting about 2,500 s. For optimal persistent luminescence, the dopant and codopant should be added in their fluoride form, in concentrations below 1 mol%. A Ca3N2 deficiency of about 5% triples the afterglow intensity. Our results show that Ba2Si5N8:Eu(,R and Ca2Si5N8:Eu(,R are promising persistent phosphors for applications requiring orange or red light.

First measurement of 153Sm in the SIR

International Nuclear Information System (INIS)

Michotte, C.; Ratel, G.; Lucas, L.

1999-01-01

In June 1998, the NIST sent to the International Reference System (SIR) a solution of 153 Sm standardized in a 4π ionization chamber. As this radionuclide had not previously been measured in the SIR, the resulting equivalent activity A e,NIST is compared with the value calculated from the efficiency curve of the SIR. However, problems occurred owing to the presence of 154 Eu and 156 Eu impurities in the solution. The manner in which the final equivalent activity value for this solution of 153 Sm has been deduced is described in this report. (authors)

Rare earth elements determination and distribution patterns in sediments of polluted marine environment by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Akyil, S.; Yusof, A.M.; Wood, A.K.H.

2001-01-01

Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a TRIGA Mk.II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area

94 β-Decay Half-Lives of Neutron-Rich _{55}Cs to _{67}Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation.

Science.gov (United States)

Wu, J; Nishimura, S; Lorusso, G; Möller, P; Ideguchi, E; Regan, P-H; Simpson, G S; Söderström, P-A; Walker, P M; Watanabe, H; Xu, Z Y; Baba, H; Browne, F; Daido, R; Doornenbal, P; Fang, Y F; Gey, G; Isobe, T; Lee, P S; Liu, J J; Li, Z; Korkulu, Z; Patel, Z; Phong, V; Rice, S; Sakurai, H; Sinclair, L; Sumikama, T; Tanaka, M; Yagi, A; Ye, Y L; Yokoyama, R; Zhang, G X; Alharbi, T; Aoi, N; Bello Garrote, F L; Benzoni, G; Bruce, A M; Carroll, R J; Chae, K Y; Dombradi, Z; Estrade, A; Gottardo, A; Griffin, C J; Kanaoka, H; Kojouharov, I; Kondev, F G; Kubono, S; Kurz, N; Kuti, I; Lalkovski, S; Lane, G J; Lee, E J; Lokotko, T; Lotay, G; Moon, C-B; Nishibata, H; Nishizuka, I; Nita, C R; Odahara, A; Podolyák, Zs; Roberts, O J; Schaffner, H; Shand, C; Taprogge, J; Terashima, S; Vajta, Z; Yoshida, S

2017-02-17

The β-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

Determination of Debye temperatures and Lamb-Mössbauer factors for LnFeO3 orthoferrite perovskites (Ln  =  La, Nd, Sm, Eu, Gd)

Science.gov (United States)

Scrimshire, A.; Lobera, A.; Bell, A. M. T.; Jones, A. H.; Sterianou, I.; Forder, S. D.; Bingham, P. A.

2018-03-01

Lanthanide orthoferrites have wide-ranging industrial uses including solar, catalytic and electronic applications. Here a series of lanthanide orthoferrite perovskites, LnFeO3 (Ln  =  La Nd; Sm; Eu; Gd), prepared through a standard stoichiometric wet ball milling route using oxide precursors, has been studied. Characterisation through x-ray diffraction and x-ray fluorescence confirmed the synthesis of phase-pure or near-pure LnFeO3 compounds. 57Fe Mössbauer spectroscopy was performed over a temperature range of 10 K-293 K to observe hyperfine structure and to enable calculation of the recoil-free fraction and Debye temperature (θ D) of each orthoferrite. Debye temperatures (Ln  =  La 474 K Nd 459 K Sm 457 K Eu 452 K Gd 473 K) and recoil-free fractions (Ln  =  La 0.827; Nd 0.817; Sm 0.816; Eu 0.812; Gd 0.826) were approximated through minimising the difference in the temperature dependent experimental centre shift and theoretical isomer shift, by allowing the Debye temperature and isomer shift values to vary. This method of minimising the difference between theoretical and actual values yields Debye temperatures consistent with results from other studies determined through thermal analysis methods. This displays the ability of variable-temperature Mössbauer spectroscopy to approximate Debye temperatures and recoil-free fractions, whilst observing temperature induced transitions over the temperature range observed. X-ray diffraction and Rietveld refinement show an inverse relationship between FeO6 octahedral volume and approximated Debye temperatures. Raman spectroscopy show an increase in the band positions attributed to soft modes of Ag symmetry, Ag(3) and Ag(5) from La to GdFeO3 corresponding to octahedral rotations and tilts in the [0 1 0] and [1 0 1] planes respectively.

Characterization of element and mineral content in Artemisia annua ...

African Journals Online (AJOL)

Dr DIALLO

2013-06-26

Jun 26, 2013 ... The mineral elements are present in different kinds of herbal leaves in various proportions .... rare earth elements (Dy, Eu, Gd, Sm, Tb and Yb) were not detected in ..... behaviour of leached aluminum in tea infusions. The Sci.

Luminescence and magnetic behaviour of almond like (Na0.5La0.5)MoO4:RE3+ (RE = Eu, Tb, Dy) nanostructures

International Nuclear Information System (INIS)

Krishnan, Rajagopalan; Thirumalai, Jagannathan; Thomas, Sabu; Gowri, Mahasampath

2014-01-01

Graphical abstract: Monodispersed almond-like (Na 0.5 La 0.5 )MoO 4 :RE 3+ nanostructures synthesized by employing ethylene-diamine tetra acetic acid (EDTA) using hydrothermal route at 200 °C for 24 h. These nanoparticles were found to be novel bi-functional candidates suitable for high-quality luminescence and magnetic applications. - Highlights: • Almond like structures of (Na 0.5 La 0.5 )MoO 4 :RE 3+ were synthesized by hydrothermal method. • Time dependent self-assembly could be the dominant process for the formation of 3D networks. • Luminescence properties of nanosamples were studied in comparison with bulk sample. • Room temperature magnetic properties of bulk and nanophosphors were investigated. - Abstract: Tetragonal phase (Na 0.5 La 0.5 )MoO 4 :RE 3+ (RE = Eu, Tb, Dy) with almond like hierarchical structures assembled from nanosheets building blocks were successfully synthesized by employing disodium ethylenediaminetetraacetic acid (Na 2 EDTA) using hydrothermal route at 200 °C for 24 h. Field emission scanning electron microscope, transmission electron microscope, and X-ray diffraction patterns were used to characterize the morphology, size, and crystal structure with good resolution. The sequestering agent EDTA acts as quadridentate ligand coordinated with metal ions [Na + , La 3+ /RE 3+ ] facilitating the formation of self-organized 3D networks. The growth mechanism for the formation of almond like nanostructures is explicated in four paths: dissolution, adsorption, in situ transformation in acidic and basic media and the effective collision. Photoluminescence excitation and emission spectra reveals a spectral blue shift which was observed in the nanosamples towards shorter wavelengths compared with the bulk sample. Upon UV irradiation, both bulk and nanostructure show strong luminescence in the red region due to the 5 D 0 → 7 F 2 transition in Eu 3+ . Also, Tb 3+ and Dy 3+ doped (Na 0.5 La 0.5 )MoO 4 phosphor exhibit green and yellow

Photoluminescence, afterglow and thermoluminescence in SrAl2O4:Eu2+,Dy3+ irradiated with blue and UV light

International Nuclear Information System (INIS)

Chernov, V.; Piters, T.M.; Melendrez, R.; Yen, W.M.; Cruz-Zaragoza, E.; Barboza-Flores, M.

2007-01-01

The luminescence in SrAl 2 O 4 :Eu 2+ ,Dy 3+ under continuous excitation is quite different from the 'standard' intra-ion photoluminescence (PL) and gradually grows during hundreds of seconds before reaching the saturation (photo-charging effect). In this work, we report the behavior of photo-charging effect under the blue and UV light irradiation at temperatures between 20 and 370 K, as well as afterglow (AG) and thermoluminescence (TL) observed after the irradiation termination. At 20 K the photo-charging effect is absent. With increasing temperature the photo-charging effect appears as a result of PL decreasing due to competitive trapping process with activation energy of 0.17 eV. The AG decay curves are described well by the Becquerel's law with the exponent close to 1. The AG decay time is about 10-50 s and practically does not depend on temperature. The TL glow curve exhibits at least seven partially overlapped peaks with maxima at 50, 65, 80, 155, 200, 250 and 290 K. The emission spectra of Eu 2+ consist of two bands at 450 and 520 nm. Both the bands are the same for the PL, AG and TL spectra, but their ratio depends on temperature and the luminescence type

High-efficient, bicolor-emitting GdVO_4:Dy"3"+ phosphor under near ultraviolet excitation

International Nuclear Information System (INIS)

Lu, Jinjin; Zhou, Jia; Jia, Huayu; Tian, Yue

2015-01-01

Bicolor emitting GdVO_4:Dy"3"+ phosphor with short columniation-shape was prepared via a simple co-precipitation process. The optimal doping concentration for obtaining maximal luminescent intensity was confirmed to be 0.3 mol% and the electric dipole–dipole interaction is responsible for concentration quenching of Dy"3"+ emission in GdVO_4 phosphor. In order to evaluate the luminescent performance of as-prepared phosphor, the luminescent efficiency and color coordinates were studied. The results show that luminescent efficiency of this phosphor is very high under near UV excitation and twice times higher than commercial Y_2O_2S:Eu"3"+ phosphor. In addition, the color coordinates for optimal Dy"3"+ concentration are (0.339, 0.379), which are close to equal energy point. Therefore, the GdVO_4:Dy"3"+ phosphor may have potential application for solid state lighting.

Red, yellow, blue and green emission from Eu3+, Dy3+ and Bi3+ doped Y2O3 nanophosphors

International Nuclear Information System (INIS)

Loitongbam, Romeo Singh; Rameshwor Singh, W.

2014-01-01

Rare earth elements (RE = Eu 3+ and Dy 3+ ) and Bi 3+ doped Y 2 O 3 nanoparticles were synthesized by urea hydrolysis method in ethylene glycol, which acts as reaction medium as well as capping agent, at a low temperature (140℃), followed by calcination of the obtained product. Scanning electron microscopy (SEM) images reveal that a highly uniform ovoid shaped Y 2 O 3 nanoparticles of around 100 nm size range were obtained in this method. The respective RE and Bi 3+ doped Y 2 O 3 precursor nanoparticles when heated at 600 and 750℃, retains the same shape as that of the as-synthesized Y 2 O 3 precursor samples. XRD pattern reveals the crystalline nature of the heated nanoparticles and indicate the absence of any impurity phase other than cubic Y 2 O 3

Titration of thorium and rare earths with ethylenediaminetetraacetic acid using semimethylthymol blue by visual end-point indication

International Nuclear Information System (INIS)

Hafez, M.A.H.; Kenawy, I.M.M.; Ramadan, M.A.M.

1994-01-01

The precision and accuracy attainable in direct complexometric titrations of Thsup(4+) consecutively with either lighter (La 3+ , Nd 3+ , Sm 3+ , Eu 3+ or Gd 3+ ) or heavier lanthanides (Dy 3+ ) in different proportions using Semimethylthymol Blue (SMTB) as a metallochromic indicator and disodium dihydrogen ethylenediaminetetraacetate were studied. Thorium (IV) was titrated at pH 2, the Ph was adjusted to 5.5-6.0 by adding hexamethylenetetramine (hexamine) buffer and acetylacetone-acetone solution and La 3+ (or Nd 3+ , Sm 3+ , Eu 3+ , Gd 3+ or Dy 3+ ) was then titrated. A comparison of the indicators SMTB and Methylthymol Blue (MTB) for successive titrations of Th 4+ and any of the rare earth ions was carried out. The proposed titration method was applied successfully to some naturally occurring ores and minerals containing thorium and some lanthanides and the results were satisfactory. (Author)

161Dy Moessbauer spectroscopy of the intermetallic compounds DyNi2Si2, DyNi2Ge2 and DyAg2Si2

International Nuclear Information System (INIS)

Onodera, Hideya; Murata, Akifumi; Koizuka, Masaaki; Ohashi, Masayoshi; Yamaguchi, Yasuo

1994-01-01

161 Dy Moessbauer spectroscopic study has been performed on DyNi 2 Si 2 , DyNi 2 Ge 2 and DyAg 2 Si 2 in order to clarify microscopic properties of antiferromagnets with incommensurate and sinusoidally moment-modulated structure. The experiments were done using the standard 161 Tb Moessbauer sources prepared by neutron irradiation at the Japan Material Testing Reactor. The Moessbauer spectra of DyNi 2 Si 2 are analyzed satisfactorily by a single set of hyperfine parameters, and hence the sinusoidal moment-modulation is considered to be realized through a distribution of spin relaxation rate. The broadened spectra of DyNi 2 Ge 2 are fitted tentatively by three subspectra. It seems for DyNi 2 Ge 2 that the incommensurate arrangement of Dy moments differed in magnitude as well as the distribution of spin relaxation rate originates the moment modulation. The fact that the spectrum of DyAg 2 Si 2 at 3 K consists of two distinct subspectra ensures the complicated antiferromagnetic structure where two kinds of Dy moments differed in magnitude are arranged noncollinearly. (author)

Oxygen perovskites with pentavalent ruthenium A/sub 2/sup(II)Bsup(III)Rusup(V)O/sub 6/ with Asup(II) = Ba, Sr

Energy Technology Data Exchange (ETDEWEB)

Bader, H; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1980-07-01

The perovskites Ba/sub 2/Bsup(III)Rusup(V)O/sub 6/ with Bsup(III) = La, Nd, Sm, Eu, Gd, Dy, Y are cubic (Bsup(III) = La: a = 8.54 A; Y: a = 8.33 A) with a partial order for Bsup(III) and Rusup(V). The Sc compound, Ba/sub 2/ScRuO/sub 6/, has a hexagonal 6L structure (a = 5.79 A; c = 14.22 A; sequence (hcc)/sub 2/). The lattice of the Sr perovskites, Sr/sub 2/Bsup(III)Rusup(V)O/sub 6/, with Bsup(III) = Eu, Gd, Dy, Y is rhombic distorted. The IR and FIR spectra are discussed.

Optical properties of SrAl{sub 2−x}Si{sub x}O{sub 4−x}N{sub x}:Eu{sup 2+}, Dy{sup 3+} phosphors for AC-LEDs

Energy Technology Data Exchange (ETDEWEB)

Li, Bowen; Xie, Qidi; Qin, Huanhui [School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020 (China); Zhang, Mei, E-mail: zmjenny@163.com [School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020 (China); He, Xin; Long, Yongbing [School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020 (China); Xing, Lusheng [LED Institute, Wuyi University, Jiangmen, Guangdong 529020 (China)

2016-09-15

Series of green emitting SrAl{sub 2−x}Si{sub x}O{sub 4−x}N{sub x}:Eu{sup 2+}, Dy{sup 3+} phosphors have been synthesized via a high temperature solid-state method. The effects of (SiN){sup +} on phase structural, emission and excitation spectra and decay curves were investigated systematically. The X-ray diffraction (XRD) patterns show that the maximum amount of solubility is about x = 0.10. The emission wavelength can be red-shifted from 509 to 515 nm with increasing (SiN){sup +} concentration. Meanwhile, the average lifetime of samples are shortened from 845.86 to 765.34 ms, which can appropriately compensate for the AC time gap and the emission color of AC-LEDs will be improved. Finally, we use these phosphors and near UV-chips to fabricate LEDs, which show more stable luminescence properties accompanying with the decrease of the luminous efficiency as the (SiN){sup +} content increases. - Highlights: • The incorporation of (SiN){sup +} can shift the emission spectra to a long wavelength. • The color purity of SrAl{sub 2−x}Si{sub x}O{sub 4−x}N{sub x}:Eu{sup 2+}, Dy{sup 3+} phosphor can be improved to 48.65%. • The performance of pc-LEDs confirms (SiN){sup +} can improve the stable of phosphors.

Preparation, characterization and luminescence of Sm~(3+) or Eu~(3+) doped Sr_2CeO_4 by a modified sol-gel method

Institute of Scientific and Technical Information of China (English)

张春祥; 史建设; 杨绪杰; 陆路德; 汪信

2010-01-01

Superfine Sr2CeO4:RE3+ (RE=Eu, Sm) phosphors were synthesized at relatively low temperature by a modified sol-gel method using nitrates as raw materials, ethylenediaminetetraacetic acid (EDTA) as complexing agent. Single phase phosphors could be obtained at calcination temperature above 800 °C and pH value higher than 6.4 of initial solution. The as-prepared powders consisted of uniform crotch-like grains. The preparation process was monitored by thermogravimetric and differential thermal analysis (TG-DTA) ...

Structural, luminescent and thermal properties of blue SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} phosphor filled low-density polyethylene composites

Energy Technology Data Exchange (ETDEWEB)

Bem, D.B. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Luyt, A.S. [Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Dejene, F.B., E-mail: dejenebf@qwa.ufs.ac.z [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 70000, Port Elizabeth 6031 (South Africa); Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa)

2009-12-01

The performance of nanophase luminophors is usually compromised by environmentally induced degradation. In this study, composites of low density polyethylene (LDPE) with various concentrations of the blue-emitting europium and dysprosium co-doped strontium aluminate (SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+}) phosphor were investigated. The blue long-lasting phosphorescence of the composites was observed in the dark after removal of the excitation light. X-ray diffraction analysis revealed the presence of the SrAl{sub 2}O{sub 4} phase in the composites. PL spectra of the composites have two sets of peaks, major broad bands peaking at about 4855 A and minor ones at wavelengths between 4115 and 4175 A, attributed to the 4f-5d transition of Eu{sup 2+}. DSC and TGA results show that the introduction of the phosphor in LDPE matrix caused a slight reduction in the crystallinity of LDPE but a significant increase in the stability of the composites.

X-ray induced Sm{sup 3+} to Sm{sup 2+} conversion in fluorophosphate and fluoroaluminate glasses for the monitoring of high-doses in microbeam radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Vahedi, Shahrzad; Okada, Go; Morrell, Brian; Muzar, Edward; Koughia, Cyril; Kasap, Safa [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A9 (Canada); Edgar, Andy; Varoy, Chris [School of Chemical and Physical Sciences and MacDiarmid Institute, Victoria University of Wellington, Kelburn Parade (New Zealand); Belev, George; Wysokinski, Tomasz [Canadian Light Source, Inc., University of Saskatchewan, Saskatoon, Saskatchewan S7N 0X4 (Canada); Chapman, Dean [Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5 (Canada)

2012-10-01

Fluorophosphate and fluoroaluminate glasses doped with trivalent samarium were evaluated as sensors of x-ray radiation for microbeam radiation therapy at the Canadian Light Source using the conversion of trivalent Sm{sup 3+} to the divalent form Sm{sup 2+}. Both types of glasses show similar conversion rates and may be used as a linear sensor up to {approx}150 Gy and as a nonlinear sensor up to {approx}2400 Gy, where saturation is reached. Experiments with a multi-slit collimator show high spatial resolution of the conversion pattern; the pattern was acquired by a confocal fluorescence microscopy technique. The effects of previous x-ray exposure may be erased by annealing at temperatures exceeding the glass transition temperature T{sub g} while annealing at T{sub A} < T{sub g} enhances the Sm conversion. This enhancement is explained by a thermally stimulated relaxation of host glass ionic matrix surrounding x-ray induced Sm{sup 2+} ions. In addition, some of the Sm{sup 3+}-doped glasses were codoped with Eu{sup 2+}-ions but the results show that there is no marked improvement in the conversion efficiency by the introduction of Eu{sup 2+}.

Distribution of stable traps for thermoluminescent processes in the phosphor SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+}; Distribucion de trampas continuas para procesos termoluminiscentes en el fosforo SrAl{sub 2}O{sub 4}: Eu{sup 2+}, Dy{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Pedroza M, M.; Castaneda, B.; Arellano T, O.; Melendrez, R.; Barboza F, M. [Universidad de Sonora, A.P. 5-088 Mexico D.F. (Mexico)

2007-07-01

Full text: The phosphor of persistent luminescence (PLUM) SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+} exhibits one thermoluminescence curve after exposing it to UV radiation. The curve is made up of a wide band with a maximum around 455 K. Starting from the experimental deconvolution method proposed by McKeever, it was solved the number of peaks in the TL curve and it was analyzed the position of each TL peak regarding to the cut temperature (T{sub stop}). In this analysis five maximum TL peaks were observed (at the diagram T{sub stop} vs T{sub max}) around the 319, 425, 457, 488 and 515 K. Also, its were also found two regions that correspond to an overlap of stable traps, the first one in the region of the 380 K at 415 K and the second of the 430 to 455 K. The existence of a distribution of stable traps can be evaluated from the curve T{sub stop} vs T{sub max} where this distribution of stable traps is presented as a monotonous lineal increase with the temperature, because the TL independent processes appear like horizontal lines exactly in the specific temperatures (319, 425, 457, 488 and 515 K) where its are liberated most of the trapped charges. Using the preheating method and initial increase for the peak in 455 K the trap depths are determined, being obtained the following values of the activation energy 0.28, 0.67, 1, 1.5 and 1.62 eV. An arrangement of stable traps plays a decisive role in the emission of the persistent luminescence. Likewise, it was determined that all the thermoluminescent processes were characterized by a re trapping of the charge, reason by which these processes followed a second order kinetics. The TL peak of low temperature 319 K is related with those electronic traps that the PLUM takes place in SrAl{sub 2}O{sub 4}: Eu{sup 2+} and with the same recombination centers. The PLUM emissions and the TL are centered around 510 nm attributed to the electronic transition 4f{sup 6}5d{sup 1} {yields}4f{sup 7} corresponding to the Eu{sup 2+} ion

Solid-state amorphization of SmFe3 by hydrogenation

International Nuclear Information System (INIS)

Mueller, K.H.; Kubis, M.; Handstein, A.; Gutfleisch, O.

2000-01-01

Hydrogen-induced amorphization (HIA) has received much attention as a method for the preparation of amorphous compounds since its discovery by Yeh et al. Meanwhile it has been observed for a large number of intermetallic compounds with C15, C23, B8 2 , DO 19 and L1 2 structures. E.G. the C15 Laves-type compounds (MgCu 2 -type structure) of rare earth (R) - transition metal (T) compounds RT 2 show HIA for R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er. Aoki et al. postulated that new amorphizing compounds can be expected at high hydrogen pressures. In this work, the structural changes of SmFe 3 (PuNi 3 -type structure) during heating in high hydrogen pressures are reported

Development of BaSO4:Eu thermoluminescence phosphor

International Nuclear Information System (INIS)

Madhusoodanan, U.; Jose, M.T.; Lakshmanan, A.R.

1999-01-01

A highly sensitive thermoluminescence (TL) phosphor based on BaSO 4 :Eu was developed following the coprecipitation technique and firing in argon atmosphere at 1123 K. Photoluminescence studies confirm that firing in argon atmosphere instead of air increased the incorporation of Eu ions in 2+ valence state. At low γ-ray doses, its TL sensitivity is nearly 2 to 3 times higher than that of CaSO 4 :Dy phosphor. The other salient features of this BaSO 4 :Eu TL phosphor are a constant glow curve shape and a nearly linear γ-ray dose response

Monodisperse and hollow structured Y{sub 2}O{sub 3}:Ln{sup 3+} (Ln = Eu, Dy, Er, Tm) nanospheres: A facile synthesis and multicolor-tunable luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Li, Ruiqing; Zi, Wenwen; Li, Linlin; Liu, Lu; Zhang, Junjun [College of Chemistry, Jilin University, Changchun 130026 (China); Zou, Lianchun, E-mail: zoulianchun@126.com [Teaching Center of Basic Courses, Jilin University, Changchun 130062 (China); Gan, Shucai, E-mail: gansc@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130026 (China)

2014-12-25

Highlights: • We reported a simple route to synthesize the Y{sub 2}O{sub 3} HNSs. • A possible formation mechanism of the Y{sub 2}O{sub 3} HNSs was proposed. • The Ln-doped Y{sub 2}O{sub 3} HNSs exhibit characteristic emission with different colors. • White-light-emitting phosphor Y{sub 2}O{sub 3}:Tm{sup 3+}, Dy{sup 3+} was also successfully synthesized. - Abstract: A novel, fast and simple method was developed to synthesize the undoped and lanthanide-doped yttrium oxide hollow nanospheres (Y{sub 2}O{sub 3}⋅HNSs) with multicolored downconversion emission under mild conditions by employing poly (acrylic acid sodium salt) microspheres (PAAS MSs) as active templates followed by a subsequent calcination process. The structure, morphology, formation process, and fluorescent properties are well investigated using various techniques. The results show that the samples can be well indexed to the pure cubic phase of Y{sub 2}O{sub 3}. The possible formation mechanism of the PAAS MSs, PAA-Y precursor, and Y{sub 2}O{sub 3} HNSs are proposed and discussed in detail. Upon ultraviolet excitation, the obtained Y{sub 2}O{sub 3}:Ln{sup 3+} (Ln = Eu, Dy, Er, Tm) HNSs exhibit strong red, yellow–green, blue, yellow emission, respectively. Moreover, a novel single-phased and near-UV-pumped white-light-emitting phosphor Y{sub 2}O{sub 3}:Tm{sup 3+}, Dy{sup 3+} was also successfully fabricated through optimizing the molar ratio among Tm{sup 3+} and Dy{sup 3+} in the Y{sub 2}O{sub 3} host. This material may find potential applications in field-emission display devices and white ultraviolet light-emitting diodes (UV LEDs). Furthermore, this synthesis route may be of great significance in the preparation of other hollow spherical materials.

Optimizing Blue Persistent Luminescence in (Sr _1-δ Ba _δ ) ₂ MgSi ₂ O _7: Eu ²⁺ ,Dy ³⁺ via Solid Solution for Use in Point-of-Care Diagnostics

Energy Technology Data Exchange (ETDEWEB)

Finley, Erin; Cobb, Angelica; Duke, Anna; Paterson, Andrew; Brgoch, Jakoah (Luminostics); (Houston)

2016-11-04

Inorganic persistent luminescent phosphors are an excellent class of optical reporters for enabling sensitive point-of-care diagnostics, particularly with smartphone-based biosensing devices in testing formats such as the lateral flow assay (LFA). Here, the development of persistent phosphors for this application is focused on the solid solution (Sr_1-δBa_δ)₂MgSi₂O₇:Eu²+,Dy³⁺ (δ = 0, 0.125, 0.25, 0.375), which is prepared using a high-temperature solid-state reaction as confirmed by synchrotron X-ray powder diffraction. The substitution of barium for strontium enables control over the Eu²⁺ 5d-orbital crystal field splitting (CFS) as a tool for tuning the emission wavelength while maintaining luminescence lifetimes >9 min across the composition range. Thermoluminescence measurements of the solid solution provide evidence that trap states contribute to the persistent lifetimes with the trap depths also remaining constant as a function of composition. Time-gated luminescence images of these compounds are captured on a smartphone arranged in a layout to mimic a point-of-care test and demonstrate the viability of using these materials as optical reporters. Moreover, comparing the blue-emitting (Sr_0.625Ba_0.375)₂MgSi₂O₇:Eu²⁺,Dy³⁺ and the green-emitting SrAl₂O_4:Eu²⁺,Dy³⁺ in a single LFA-type format shows these two compounds can be detected and resolved simultaneously, thereby permitting the development of a multiplexed LFA.

Ordered perovskites with cationic vacancies. 9. Compounds of the type Sr/sub 2/Srsub(1/4)Bsub(1/2)sup(III)vacantsub(1/4)WO/sub 6/ equivalent to Sr/sub 8/SrB/sub 2/sup(III)vacantW/sub 4/O/sub 24/ (Bsup(III) = La, Pr, Nd, Sm - Tm, Y)

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S; Ehmann, A [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1981-08-01

The compounds Sr/sub 2/Srsub(1/4)Bsub(1/2)sup(III)vacantsub(1/4)WO/sub 6/ equivalent to Sr/sub 8/SrB/sub 2/sup(III)vacantW/sub 4/O/sub 24/ belong to the group of perovskites with octahedral cationic vacancies (cation/vacancy ratio (CN 6) = 7:1). For the larger Bsup(III) ions (La, Pr, Nd, Sm-Dy) different ordering effects are observed. The perovskites with Bsup(III) = Sm, Eu, Gd are polymorphic too (HT modification: higher ordered cubic perovskite (Bsup(III) = Gd: a = 2 x 8.23/sub 4/ A); LT modification: hexagonal perovskite stacking polytype (Bsup(III) = Gd: a = 9.95/sub 4/ A; c = 19.0/sub 4/ A)). With the smaller Bsup(III) ions (Ho, Er, Tm and Y) a cubic, 1:1 ordered perovskite type is observed.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Permanent link: https://www.ias.ac.in/article/fulltext/boms/039/03/0603-0611. Keywords. Predominance area diagram; Kellogg diagram; lanthanide oxychloride; rare-earth mineral processing; thermodynamic properties. Abstract. Isothermal stability field diagrams for Ln−O−Cl systems (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, ...

Synthesis, characterization and properties of lanthanide trifluoroacetate complexes with N-(1-adamantyl) acetamide

International Nuclear Information System (INIS)

Miranda Junior, P.; Isolani, P.C.; Vicentini, G.; Zinner, L.B.

1999-01-01

Complexes of lanthanide trifluoacetates and N-(1-adamantyl) acetamide (ADA) with composition Ln (TFA) 3 .ADA (Ln=Nd, Sm, Eu, Gd, Tb, Dy; TFA trifluoroacetate) were synthesized by titration of lanthanides with EDTA and CHN microanalytical procedures. According to IR spectra the bonding of ADA occurs through the carbonyl oxygen. Compounds of Nd 3+ , Sm 3+ and Eu 3+ present two bands attributed to v aa COO and that of Gd 3+ Tb 3+ only one. In all cases only one band is attributed to v a -s COO. The absorption spectra of the neodymium and the emission spectra of the europium compounds were determined and interpreted. (author)

Wavelength dependent loading of traps in the persistent phosphor SrAl{sub 2}O{sub 4}:Eu{sup 2+}, Dy{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Hagemann, H.; Lovy, D. [Department of Physical Chemistry, University of Geneva, Quai E. Ansermet 30, CH-1211 Geneva 4 (Switzerland); Yoon, S.; Pokrant, S. [Laboratory Materials for Energy Conversion, Empa-Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600, Dübendorf (Switzerland); Gartmann, N.; Walfort, B. [LumiNova AG, Speicherstrasse 60a, CH-9053, Teufen (Switzerland); Bierwagen, J., E-mail: Jakob.Bierwagen@unige.ch [Department of Physical Chemistry, University of Geneva, Quai E. Ansermet 30, CH-1211 Geneva 4 (Switzerland)

2016-02-15

The persistent phosphorescence and thermoluminescence of SrAl{sub 2}O{sub 4}:Eu{sup 2+}:Dy{sup 3+} is reported for a variety of different excitation wavelengths and excitation temperatures, to provide new insights in the mechanism of the trapping and detrapping. These measurements reveal that the trapping is strongly dependent on the wavelength and temperature. First, with increasing loading temperature, the thermoluminescence peak shifts to lower temperatures which corresponds to a change of trap population. Secondly, the integrated thermoluminescent intensity increases with increasing loading temperature. All wavelength and temperature dependent experiments indicate that the loading of the traps is a thermally activated processes. Utilizing different wavelengths for loading, this effect can be enhanced or reduced. Furthermore excitation with UV-B-light reveals a tendency for detrapping the phosphor, reducing the resulting thermoluminescent intensity and changing the population of the traps.

Development of BaSO sub 4 :Eu thermoluminescence phosphor

CERN Document Server

Madhusoodanan, U; Lakshmanan, A R

1999-01-01

A highly sensitive thermoluminescence (TL) phosphor based on BaSO sub 4 :Eu was developed following the coprecipitation technique and firing in argon atmosphere at 1123 K. Photoluminescence studies confirm that firing in argon atmosphere instead of air increased the incorporation of Eu ions in 2+ valence state. At low gamma-ray doses, its TL sensitivity is nearly 2 to 3 times higher than that of CaSO sub 4 :Dy phosphor. The other salient features of this BaSO sub 4 :Eu TL phosphor are a constant glow curve shape and a nearly linear gamma-ray dose response.

Combustion synthesis of Eu and Dy activated Sr3(VO4)2 phosphor ...

Indian Academy of Sciences (India)

phosphor as well as Sr3(VO4)2:Dy is blue and yellow emitting phosphor for solid state lighting i.e. white LEDs. The ... 2004; Pang et al 2004) doped with rare earth has expanded ... controlled since the LED light output (intensity and colour).

High-Precision Measurement of Eu/Eu* in Geological Glasses via LA-ICP-MS Analysis

Science.gov (United States)

Tang, Ming; McDonough, William F.; Arevalo, Ricardo, Jr.

2014-01-01

Elemental fractionation during laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis has been historically documented between refractory and volatile elements. In this work, however, we observed fractionation between light rare earth elements (LREEs) and heavy rare earth elements (HREEs) when using ablation strategies involving large spot sizes (greater than 100 millimeters) and line scanning mode. In addition: (1) ion yields decrease when using spot sizes above 100 millimeters; (2) (Eu/Eu*)(sub raw) (i.e. Europium anomaly) positively correlates with carrier gas (He) flow rate, which provides control over the particle size distribution of the aerosol reaching the ICP; (3) (Eu/Eu*)(sub raw) shows a positive correlation with spot size, and (4) the changes in REE signal intensity, induced by the He flow rate change, roughly correlate with REE condensation temperatures. The REE fractionation is likely driven by the slight but significant difference in their condensation temperatures. Large particles may not be completely dissociated in the ICP and result in preferential evaporation of the less refractory LREEs and thus non-stoichiometric particle-ion conversion. This mechanism may also be responsible for Sm-Eu-Gd fractionation as Eu is less refractory than Sm and Gd. The extent of fractionation depends upon the particle size distribution of the aerosol, which in turn is influenced by the laser parameters and matrix. Ablation pits and lines defined by low aspect ratios produce a higher proportion of large particles than high aspect ratio ablation, as confirmed by measurements of particle size distribution in the laser induced aerosol. Therefore, low aspect ratio ablation introduces particles that cannot be decomposed and/or atomized by the ICP and thus results in exacerbated elemental fractionation. Accurate quantification of REE concentrations and Eu/Eu* requires reduction of large particle production during laser ablation. For the reference

Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores

NARCIS (Netherlands)

Malkin, B. Z.; Lummen, T. T. A.; van Loosdrecht, P. H. M.; Dhalenne, G.; Zakirov, A. R.

2010-01-01

The experimental temperature dependence (T = 2-300 K) of single crystal bulk and site susceptibilities of rare earth titanate pyrochlores R2Ti2O7 (R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) is analyzed in the framework of crystal field theory and a mean field approximation. Analytical expressions for the

Luminescence and magnetic properties of novel nanoparticle-sheathed 3D Micro-Architectures of Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) for bifunctional application

Science.gov (United States)

Krishnan, Rajagopalan; Thirumalai, Jagannathan; Kathiravan, Arunkumar

2015-01-01

For the first time, we report the successful synthesis of novel nanoparticle-sheathed bipyramid-like and almond-like Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) 3D hierarchical microstructures through a simple disodium ethylenediaminetetraacetic acid (Na2EDTA) facilitated hydrothermal method. Interestingly, time-dependent experiments confirm that the assembly-disassembly process is responsible for the formation of self-aggregated 3D architectures via Ostwald ripening phenomena. The resultant products are characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and magnetic measurements. The growth and formation mechanisms of the self-assembled 3D micro structures are discussed in detail. To confirm the presence of all the elements in the microstructure, the energy loss induced by the K, L shell electron ionization is observed in order to map the Fe, Gd, Mo, O, and Eu components. The photo luminescence properties of Fe0.5R0.5(MoO4)1.5 doped with Eu3+, Tb3+, Dy3+ are investigated. The room temperature and low temperature magnetic properties suggest that the interaction between the local-fields introduced by the magnetic Fe3+ ions and the R3+ (La, Gd) ions in the dodecahedral sites determine the magnetism in Fe0.5R0.5(MoO4)1.5:Eu3+. This work provides a new approach to synthesizing the novel Fe0.5R0.5(MoO4)1.5:Ln3+ for bi-functional magnetic and luminescence applications.

Investigation of complexes with bone affinity using the In vivo generator system 166 Dy/166 Ho

International Nuclear Information System (INIS)

Pedraza L, M.

2006-01-01

The importance of this original research lies in the fact that it has proven that the [ 166 Dy]Dy/ 166 Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as 166 Ho-DOTMP or 153 Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with 166 Dy/ 166 Ho; to evaluate the in vitro and in vivo stability of both 166 Dy-EDTMP and 166 Ho-EDTMP complexes when the daughter 166 Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [ 166 Dy]Dy/ 166 Ho-EDTMP in vivo generator system. 166 Dy was obtained by neutron irradiation of enriched 164 Dy 2 O 3 in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of 166 DyCl 3 to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that 166 Dy/ 166 Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus subsequent to β decay of 166 Dy, which could release free 166 Ho 3+ . Biodistribution in mice

Investigation of complexes with bone affinity using the In vivo generator system {sup 166} Dy/{sup 166} Ho; Investigacion de complejos con afinidad osea utilizando el Sistema de Generador in vivo {sup 166} Dy/{sup 166} Ho

Energy Technology Data Exchange (ETDEWEB)

Pedraza L, M

2006-07-01

The importance of this original research lies in the fact that it has proven that the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as {sup 166}Ho-DOTMP or {sup 153}Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with {sup 166}Dy/{sup 166}Ho; to evaluate the in vitro and in vivo stability of both {sup 166}Dy-EDTMP and {sup 166}Ho-EDTMP complexes when the daughter {sup 166}Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system. {sup 166}Dy was obtained by neutron irradiation of enriched {sup 164}Dy{sub 2}O{sub 3} in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of {sup 166}DyCl{sub 3} to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that {sup 166}Dy/{sup 166}Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus

Solid-state amorphization of SmFe{sub 3} by hydrogenation

Energy Technology Data Exchange (ETDEWEB)

Mueller, K.H.; Kubis, M.; Handstein, A.; Gutfleisch, O.

2000-05-10

Hydrogen-induced amorphization (HIA) has received much attention as a method for the preparation of amorphous compounds since its discovery by Yeh et al. Meanwhile it has been observed for a large number of intermetallic compounds with C15, C23, B8{sub 2}, DO{sub 19} and L1{sub 2} structures. E.G. the C15 Laves-type compounds (MgCu{sub 2}-type structure) of rare earth (R) - transition metal (T) compounds RT{sub 2} show HIA for R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er. Aoki et al. postulated that new amorphizing compounds can be expected at high hydrogen pressures. In this work, the structural changes of SmFe{sub 3} (PuNi{sub 3}-type structure) during heating in high hydrogen pressures are reported.

Structures, magnetic, and thermal properties of Ln3MoO7 (Ln=La, Pr, Nd, Sm, and Eu)

International Nuclear Information System (INIS)

Nishimine, Hiroaki; Wakeshima, Makoto; Hinatsu, Yukio

2005-01-01

Ternary lanthanide-molybdenum oxides Ln 3 MoO 7 (Ln=La, Pr, Nd, Sm, Eu) have been prepared. Their structures were determined by X-ray diffraction measurements. They crystallize in a superstructure of cubic fluorite and the space group is P2 1 2 1 2 1 . The Mo ion is octahedrally coordinated by six oxygens and the slightly distorted octahedra share corners forming a zig-zag chain parallel to the b-axis. These compounds have been characterized by magnetic susceptibility and specific heat measurements. The La 3 MoO 7 shows complex magnetic behavior at 150 and 380K. Below these temperatures, there is a large difference in the temperature-dependence of the magnetic susceptibility measured under zero-field-cooled condition and under field-cooled condition. The Nd 3 MoO 7 show a clear antiferromagnetic transition at 2.5K. From the susceptibility measurements, both Pr 3 MoO 7 and Sm 3 MoO 7 show the existence of magnetic anomaly at 8.0 and 2.5K, respectively. The results of the specific heat measurements also show anomalies at the corresponding magnetic transition temperatures. The differential scanning calorimetry measurements indicate that two phase-transitions occur for any Ln 3 MoO 7 compound in the temperature range between 370 and 710K

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

Science.gov (United States)

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

2011-07-01

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

Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien)2(μ-1κ,2κ2-AsS4)]n (Ln==Sm, Eu, Gd) and [Ln(dien)2(1κ2-AsS4)] (Ln==Tb, Dy, Ho)

International Nuclear Information System (INIS)

Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian

2013-01-01

Solvothermal reactions of Ln 2 O 3 , As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien) 2 (μ-1κ,2κ 2 -AsS 4 )] n [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien) 2 (1κ 2 -AsS 4 )] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln 2 O 3 oxides were converted to [Ln(dien) 2 ] 3+ complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS 4 unit. In 1−3, the AsS 4 units interconnect the [Ln(dien) 2 ] 3+ cations via Ln−S bonds as tridentate μ-1κ,2κ 2 -AsS 4 bridging ligands, resulting in the neutral coordination polymers [Ln(dien) 2 (μ-1κ,2κ 2 -AsS 4 )] n (Ln1). In 4−6, the AsS 4 units coordinate with the Ln 3+ ion of [Ln(dien) 2 ] 3+ as 1κ 2 -AsS 4 chelating ligands to form neutral coordination compounds [Ln(dien) 2 (1κ 2 -AsS 4 )] (Ln2). The Ln 3+ ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln 3+ ions. Optical absorption spectra showed that 1−6 have potential use as semiconductors with the band gaps in the range 2.18−3.21 eV. - Graphical abstract: Two types of Ln-thioarsenates [Ln(dien) 2 (μ-1κ,2κ 2 -AsS 4 )] n and [Ln(dien) 2 (1κ 2 -AsS 4 )] were prepared by solvothermal methods and the soft Lewis basic AsS 4 3– ligand to Ln(III) centers with polyamine co-ligand was obtained. Display Omitted - Highlights: • Lanthanide thioarsenates were prepared by solvothermal methods. • The soft Lewis basic AsS 4 ligand coordinate Ln 3+ ions with coexistence polyamine ligands. • Two structural types of Ln-thioarsenates with structural turnover at Tb were obtained along Ln series. • The Ln-thioarsenates are potential semiconductors with optical band gaps in the range 2.18−3.21 eV

Preparation of high-temperature superconducting ceramics

International Nuclear Information System (INIS)

Causa, M.T.; Dutrus, S.M.; Esparza, Daniel; Fainstein, Carlos; Malachevsky, M.T.; Salva, Horacio; Sanchez, Rodolfo; Steren, L.B.; Tovar, Manuel; Veglio, Nestor

1987-01-01

We have prepared samples of the family ABa2Cu3Ox (A=Y, Gd, Eu, Dy, Sm, Er). The powdered samples were characterized by X-ray diffraction at room temperature. We have also studied the effect of Fe impurities in YBa2Cu3Ox and EuBa2Cu3Ox. Moreover, single crystals of YBa2Cu3Ox and La(1-x)SrxCuO4 were grown using cooper oxide flux. (Author) [es

Stability field diagrams for Ln–O–Cl systems

Indian Academy of Sciences (India)

at 1000 K. All the lanthanide elements form stable LnCl3 and LnOCl. Dichlorides of Nd, Sm, Eu, Dy, Tm and Yb ... tion of lanthanide elements from oxide ores involves carbo- chlorination [4], although other chlorinating ... versa. The purpose of this communication is to gather data on. LnOCl compounds, estimate missing ...

Rare earth analysis in human biological samples by atomic absorption using electrothermal atomization

International Nuclear Information System (INIS)

Citron, I.M.; Holtzman, R.B.; Leiman, J.

1982-01-01

The determination of Sc and seven rare earth elements, Nd, Sm, Dy, Ho, Eu, Tm, and Yb, in biological samplesby atomic absorption spectrophotometric analysis (AAS) using electrothermal atomization in a pyrolytic graphite tube is shown to be rapid, precise and accurate. The technique utilizes the method of standard additions and linear regression analysis to determine results from peak area data. Inter-elemental interferences are negligible. The elements found sensitive enough for this type of analysis are, in order of decreasing sensitivity, Yb, Eu, Tm, Dy, Sc, Ho, Sm and Nd. The determination in these types of materials of Gd and elements less sensitive to AAS detection than Gd does not appear to be feasible. Results are presented on the concentrations of these elements in 41 samples from human subjects, cows and vegetables with normal environmental exposure to the rare earth elements. The composite percent mean deviation in peak-area readings for all samples and all elements examined was 4%. The mean standard error in the results among samples was about 6.5%

Addition compounds between same phosphinoxides and hexafluorophosphates of rare earths (III)

International Nuclear Information System (INIS)

Silva, A.M. da; Melo, S.M.; Souza, E.F. de; Almeida, M.A. de

1984-01-01

Coordination compounds were prepared from salts of lanthanide hexafluorophosphates and three different phosphine oxides: methyldiphenylphosphine oxide (MDPPO), diphenylcyclohexylphosphine oxide (DPcHPO) and phosphoric acid trimethylester (TMxPO). The analytical results indicated the following general formulae : Ln(PF 6 ) 3 .5DPChPO where Ln = La, Eu, Gd, Tb and Dy; Ln(PF 6 ) 3 6MDPPO, where Ln = La, Ce, Nd, Eu, Gd, and Tm; Ln(PF 6 ) 3 .7TMxPO, where Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb. The vibrational studies in the infrared region showed that all the phosphine oxides coordination are through the oxygen of the phosphoryl group and confirmed the non-coordination character of the PF - 6 ion. Fluorescence spectra in the visible region for the Eu (III) compounds, at the liquid nitrogen temperature indicated the microsymmetry C sub(3v) as the most probable for the Eu (III) in the compounds Eu (PF 6 ) 3 .5DPChPO and Eu (PF 6 ) 3 .7TMxPO. The symmetry site of the Eu (PF 6 ) 3 .6MDPPO compound is octahedral with tetragonal distortion. (Author) [pt

Investigation of complexes with bone affinity using the In vivo generator system {sup 166} Dy/{sup 166} Ho; Investigacion de complejos con afinidad osea utilizando el Sistema de Generador in vivo {sup 166} Dy/{sup 166} Ho

Energy Technology Data Exchange (ETDEWEB)

Pedraza L, M

2006-07-01

The importance of this original research lies in the fact that it has proven that the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system is a stable complex that can be used as a therapeutic radiopharmaceutical. Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. Bone-seeking radiopharmaceuticals such as {sup 166}Ho-DOTMP or {sup 153}Sm-DTMP, have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other hematological malignancies or have shown excellent results in palliative bone metastasis pain therapy, respectively. As lanthanides have similar chemical characteristics the phosphonate with bone affinity (EDTMP) labeled with Dy/Ho can be used for marrow ablation while causing minimal irradiation to normal organs. This in vivo generator system has not been previously reported. The aim of this research was to label EDTMP (ethylene diamine tetramethylene phosphonate) with {sup 166}Dy/{sup 166}Ho; to evaluate the in vitro and in vivo stability of both {sup 166}Dy-EDTMP and {sup 166}Ho-EDTMP complexes when the daughter {sup 166}Ho is formed as a dysprosium decay product; to determine the bone marrow cytotoxic and genotoxic effect in mice and to evaluate, by histopathology, the myeloablative potential of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system. {sup 166}Dy was obtained by neutron irradiation of enriched {sup 164}Dy{sub 2}O{sub 3} in a TRIGA Mark III reactor. Labeling was carried out in an aqueous phosphate medium at pH 8.0 by addition of {sup 166}DyCl{sub 3} to EDTMP at a molar ratio 1:1.75, with >99 % radiochemical purity, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). In vitro studies demonstrated that {sup 166}Dy/{sup 166}Ho-EDTMP is unstable after dilution in saline but stable in human serum with no translocation of the daughter nucleus

Quantitative spark-source analysis of UO2-PuO2 for rare earths and tantalum, tungsten

International Nuclear Information System (INIS)

Alkire, G.J.

A quantitative analytical technique good to 20% for the determination of Sm, Eu, Gd, Dy, Ta, and W in Pu-U mixed oxides by spark source mass spectrography has been developed. The technique uses La as an added internal standard and an electronic integrator to measure peak areas of each line photometered on the densitometer. 3 tables

Stability of rare earth complexes with 2-(o-hydroxyphenyl)benzimidazole in aqueous-dioxane medium. Ustojchivost' kompleksnykh soedinenij RZEh s 2-(o-oksifenil)benzimidazolom v vodno-dioksanovoj srede

Energy Technology Data Exchange (ETDEWEB)

Akhrimenko, Z M; Panyushkin, V T; Fedorova, M V [Kubanskij Gosudarstvennyj Univ., Krasnodar (USSR)

1990-01-01

Method of potentiometric titration was used to determine protonation constants of 2-(-hydroxyphenyl)benzimidazole (pK{sub 1}=4.5; pK{sub 2}=11.30) and stability constants of Pr,Nd,Sm,Eu,Tb,Dy complexes with this ligand. Nonmonotonous change of lgK{sub 1} with increase of ordinal number of rare earth element was revealed.

A binuclear Fe(III)Dy(III) single molecule magnet. Quantum effects and models.

Science.gov (United States)

Ferbinteanu, Marilena; Kajiwara, Takashi; Choi, Kwang-Yong; Nojiri, Hiroyuki; Nakamoto, Akio; Kojima, Norimichi; Cimpoesu, Fanica; Fujimura, Yuichi; Takaishi, Shinya; Yamashita, Masahiro

2006-07-19

The binuclear [FeIII(bpca)(mu-bpca)Dy(NO3)4], having Single Molecule Magnet (SMM) properties, belonging to a series of isostructural FeIIILnIII complexes (Ln = Eu, Gd, Tb, Dy, Ho) and closely related FeIILnIII chain structures, was characterized in concise experimental and theoretical respects. The low temperature magnetization data showed hysteresis and tunneling. The anomalous temperature dependence of Mössbauer spectra is related to the onset of magnetic order, consistent with the magnetization relaxation time scale resulting from AC susceptibility measurements. The advanced ab initio calculations (CASSCF and spin-orbit) revealed the interplay of ligand field, spin-orbit, and exchange effects and probed the effective Ising nature of the lowest states, involved in the SMM and tunneling effects.

DTA AND MOSSBAUER STUDIES IN RARE EARTH ORTHOFERRITES

Energy Technology Data Exchange (ETDEWEB)

Eibschuetz, M.; Gorodetsky, G.; Shtrikman, S.; Treves, D.

1963-11-15

Curie temperatures of 14 different orthoferrites with the chemical formula RFeO/sub 3/ (R = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were measured by differential thermal analysis. Hyperfine interactions of the Fe/ sup 57/ nucleus in the same materials were determined from their Mossbauer spectra. It is found that the quadrupole splitting with the exception of the case of Sm, isomer shift, Curie temperature, and internal field vary regularly with the ionic size of R. (auth)

Luminescence and magnetic behaviour of almond like (Na{sub 0.5}La{sub 0.5})MoO{sub 4}:RE{sup 3+} (RE = Eu, Tb, Dy) nanostructures

Energy Technology Data Exchange (ETDEWEB)

Krishnan, Rajagopalan [Department of Physics, B.S. Abdur Rahman University, Vandalur, Chennai, Tamil Nadu (India); Thirumalai, Jagannathan, E-mail: jthirumalai@bsauniv.ac.in [Department of Physics, B.S. Abdur Rahman University, Vandalur, Chennai, Tamil Nadu (India); Thomas, Sabu [Polymer Science and Technology, Center for Nanoscience and Nanotechnology, School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686 560, Kerala (India); Gowri, Mahasampath [Department of Chemistry, B.S. Abdur Rahman University, Vandalur, Chennai, Tamil Nadu (India)

2014-08-01

Graphical abstract: Monodispersed almond-like (Na{sub 0.5}La{sub 0.5})MoO{sub 4}:RE{sup 3+} nanostructures synthesized by employing ethylene-diamine tetra acetic acid (EDTA) using hydrothermal route at 200 °C for 24 h. These nanoparticles were found to be novel bi-functional candidates suitable for high-quality luminescence and magnetic applications. - Highlights: • Almond like structures of (Na{sub 0.5}La{sub 0.5})MoO{sub 4}:RE{sup 3+} were synthesized by hydrothermal method. • Time dependent self-assembly could be the dominant process for the formation of 3D networks. • Luminescence properties of nanosamples were studied in comparison with bulk sample. • Room temperature magnetic properties of bulk and nanophosphors were investigated. - Abstract: Tetragonal phase (Na{sub 0.5}La{sub 0.5})MoO{sub 4}:RE{sup 3+} (RE = Eu, Tb, Dy) with almond like hierarchical structures assembled from nanosheets building blocks were successfully synthesized by employing disodium ethylenediaminetetraacetic acid (Na{sub 2}EDTA) using hydrothermal route at 200 °C for 24 h. Field emission scanning electron microscope, transmission electron microscope, and X-ray diffraction patterns were used to characterize the morphology, size, and crystal structure with good resolution. The sequestering agent EDTA acts as quadridentate ligand coordinated with metal ions [Na{sup +}, La{sup 3+}/RE{sup 3+}] facilitating the formation of self-organized 3D networks. The growth mechanism for the formation of almond like nanostructures is explicated in four paths: dissolution, adsorption, in situ transformation in acidic and basic media and the effective collision. Photoluminescence excitation and emission spectra reveals a spectral blue shift which was observed in the nanosamples towards shorter wavelengths compared with the bulk sample. Upon UV irradiation, both bulk and nanostructure show strong luminescence in the red region due to the {sup 5}D{sub 0} → {sup 7}F{sub 2} transition in Eu{sup 3

Effect of trivalent transition metal ion substitution in Dy2O3 system

International Nuclear Information System (INIS)

Dhilip, M.; Saravana Kumar, K.; Anbarasu, V.

2015-01-01

One of the very promising approaches to create novel materials is to combine different physical properties in one material to achieve rich functionality. Magnetoelectric multiferroics are attracting attention for fundamental physics due to their unique coupling behaviour between ferroelectricity, ferromagnetism and ferroelasticity and also because of their promising applications for devices in spintronics, information storage, sensing and actuation. The existence of spontaneous magnetization in the perovskite like phase (layer of perovskite) has encouraged exploring the possibility of fabrication of a multiferroic material for multifunctional devices using the concept of magnetoelectric effect. The rare earth orthoferrites (LnFeO 3 where, Ln = La, Sm, Gd, Dy, Er and Yb) are a class of materials having potential for various applications. These compounds and metal ion substituted ferrites crystallising in perovskite structure show promise as catalysts gas separators, cathodes in solid oxide fuel cells, sensor materials, magneto-optic materials and as spin valves. In this present work, Fe substituted in Dysprosium Oxide compounds were prepared by standard solid state reaction at a temperature of 1300℃. The structural analysis of the prepared samples was characterized with powder X-Ray Diffraction technique and the lattice parameters were calculated with PodwerX indexing software. The structural analysis reveals that the substitution of Fe in Dy 2 O 3 system leads to change of crystalline structure from Cubic to Tetragonal. Further, decreasing trend of volume of the unit cell confirms the occupation of smaller ionic radii element Fe in the Dy site of Dy 2 O 3 system. Hence the possibilities of incorporation of trivalent transition metal ion in to the host Dy 2 O 3 site were analyzed. (author)

Molecular assembly and magnetic dynamics of two novel Dy6 and Dy8 aggregates.

Science.gov (United States)

Guo, Yun-Nan; Chen, Xiao-Hua; Xue, Shufang; Tang, Jinkui

2012-04-02

Complexation of dysprosium(III) with the heterodonor chelating ligand o-vanillin picolinoylhydrazone (H(2)ovph) in the presence of a carbonato ligand affords two novel Dy(6) and Dy(8) clusters, namely, [Dy(6)(ovph)(4)(Hpvph)(2)Cl(4)(H(2)O)(2)(CO(3))(2)]·CH(3)OH·H(2)O·CH(3)CN (2) and [Dy(8)(ovph)(8)(CO(3))(4)(H(2)O)(8)]·12CH(3)CN·6H(2)O (3). Compound 2 is composed of three petals of the Dy(2) units linked by two carbonato ligands, forming a triangular prism arrangement, while compound 3 possesses an octanuclear core with an unprecedented tub conformation, in which Dy(ovph) fragments are attached to the sides of the carbonato core. The static and dynamic magnetic properties are reported and discussed. In the Dy(6) aggregate, three Dy(2) "skeletons", having been well preserved (see the scheme), contribute to the single-molecule-magnet behavior with a relatively slow tunneling rate, while the Dy(8) cluster only exhibits a rather small relaxation barrier.

Magnetic moments of high spin rotational states in 158Dy and 164Dy+

International Nuclear Information System (INIS)

Seiler-Clark, G.

1983-09-01

For the study of their magnetic moments yrast states in 158 Dy and 164 Dy were excited via the multiple-Coulomb excitation by a 4.7 MeV/u 208 Pb beam. Hereby especially the question was of interest, how the one-particle effects in the nuclear structure in the region of the backbending anomaly in 158 Dy take effects on the g-factors of the high spin states in this region. The particle-γ angular correlations perturbed in the transient magnetic field during the passing of the excited Dy ions through a thin magnetized iron foil were measured. By the selective position-sensitive detection of Dy recoil ions and Pb projectiles under forward angles it was possible to determine additionally to the g-factors in the backbending region also g-factors in the spin region I 158 Dy and 164 Dy by detection of the particle-γ correlations precessing in the static hyperfine field after implantation in iron. The static hyperfine field was at the 4 + state in 164 Dy determined to B (Dy,Fe) = 245+-25 T. The g-factors were determined by comparison of the experimental results with calculations of the perturbed angular correlations by time-differential regarding of the population and de-excitation of the yrast states as well as by precession and hyperfine-relaxation effects during the flight of the Dy ions in the vacuum. (orig./HSI) [de

Room temperature synthesis of hydrophilic Ln(3+)-doped KGdF4 (Ln = Ce, Eu, Tb, Dy) nanoparticles with controllable size: energy transfer, size-dependent and color-tunable luminescence properties.

Science.gov (United States)

Yang, Dongmei; Li, Guogang; Kang, Xiaojiao; Cheng, Ziyong; Ma, Ping'an; Peng, Chong; Lian, Hongzhou; Li, Chunxia; Lin, Jun

2012-06-07

In this paper, we demonstrate a simple, template-free, reproducible and one-step synthesis of hydrophilic KGdF(4): Ln(3+) (Ln = Ce, Eu, Tb and Dy) nanoparticles (NPs) via a solution-based route at room temperature. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) and cathodoluminescence (CL) spectra are used to characterize the samples. The results indicate that the use of water-diethyleneglycol (DEG) solvent mixture as the reaction medium not only allows facile particle size control but also endows the as-prepared samples with good water-solubility. In particular, the mean size of NPs is monotonously reduced with the increase of DEG content, from 215 to 40 nm. The luminescence intensity and absolute quantum yields for KGdF(4): Ce(3+), Tb(3+) NPs increase remarkably with particle sizes ranging from 40 to 215 nm. Additionally, we systematically investigate the magnetic and luminescence properties of KGdF(4): Ln(3+) (Ln = Ce, Eu, Tb and Dy) NPs. They display paramagnetic and superparamagnetic properties with mass magnetic susceptibility values of 1.03 × 10(-4) emu g(-1)·Oe and 3.09 × 10(-3) emu g(-1)·Oe at 300 K and 2 K, respectively, and multicolor emissions due to the energy transfer (ET) process Ce(3+)→ Gd(3+)→ (Gd(3+))(n)→ Ln(3+), in which Gd(3+) ions play an intermediate role in this process. Representatively, it is shown that the energy transfer from Ce(3+) to Tb(3+) occurs mainly via the dipole-quadrupole interaction by comparison of the theoretical calculation and experimental results. This kind of magnetic/luminescent dual-function materials may have promising applications in multiple biolabels and MR imaging.

Heterogeneous bilayer films NiFe (Fe)-Dy: magnetic circular dichroism and Dy spin ordering

Energy Technology Data Exchange (ETDEWEB)

Markov, V.V. E-mail: ise@iph.krasn.ruise@iph.krasnoyarsk.su; Kesler, V.G.; Khudyakov, A.E.; Edelman, I.S.; Bondarenko, G.V

2001-08-01

Results of the magnetic circular dichroism (MCD) and Auger electron spectroscopy (AES) investigations in the 3d transition metal-Dy bi-layer films are presented. It is shown that even at room temperature the Dy layer makes a contribution to MCD of the bi-layer film, which corresponds to the MCD value in the single-layer Dy film measured below T{sub C}=85 K. According to the AES data there is no sharp interface between 3d and Dy layers in these films. Some amount of Ni and Fe atoms is dispersed in the Dy layer and some amount of Dy atoms is dispersed in the 3d layer. The comparison of the MCD and AES data allows one to suppose the Dy layer in the bi-layer films to be magnetically ordered at room temperature under the influence of the 3d-layer spin system. The influence spreads to long distances inside Dy layer through the 3d-ions dispersed in it.

Heterogeneous bilayer films NiFe (Fe)-Dy: magnetic circular dichroism and Dy spin ordering

International Nuclear Information System (INIS)

Markov, V.V.; Kesler, V.G.; Khudyakov, A.E.; Edelman, I.S.; Bondarenko, G.V.

2001-01-01

Results of the magnetic circular dichroism (MCD) and Auger electron spectroscopy (AES) investigations in the 3d transition metal-Dy bi-layer films are presented. It is shown that even at room temperature the Dy layer makes a contribution to MCD of the bi-layer film, which corresponds to the MCD value in the single-layer Dy film measured below T C =85 K. According to the AES data there is no sharp interface between 3d and Dy layers in these films. Some amount of Ni and Fe atoms is dispersed in the Dy layer and some amount of Dy atoms is dispersed in the 3d layer. The comparison of the MCD and AES data allows one to suppose the Dy layer in the bi-layer films to be magnetically ordered at room temperature under the influence of the 3d-layer spin system. The influence spreads to long distances inside Dy layer through the 3d-ions dispersed in it

Level densities and γ-strength functions in 148,149Sm

International Nuclear Information System (INIS)

Siem, S.; Guttormsen, M.; Ingeberg, K.; Melby, E.; Rekstad, J.; Schiller, A.; Voinov, A.

2002-01-01

The level densities and γ-strength functions of the weakly deformed 148 Sm and 149 Sm nuclei have been extracted. The temperature versus excitation energy curve, derived within the framework of the microcanonical ensemble, shows structures, which we associate with the breakup of Cooper pairs. The nuclear heat capacity is deduced within the framework of both the microcanonical and canonical ensembles. We observe negative heat capacity in the microcanonical ensemble whereas the canonical heat capacity exhibits an S shape as a function of temperature, both signals of a phase transition. The structures in the γ-strength functions are discussed in terms of the pygmy resonance and the scissors mode built on excited states. The samarium results are compared with data for the well-deformed 161,162 Dy, 166,167 Er, and 171,172 Yb isotopes and with data from (n,γ) experiments and giant dipole resonance studies

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

The rare earth elements like La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and the heavy metals like Mg, V, Cr, Mn, Fe, Cu, Zn, U, Th were analysed by using standard analytical methods. The Post-Archean Australian Shale composition was used to normalise the rare earth elements. It was found that the sediments ...

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Abstract. Elastic moduli (, ), Poisson's ratio (), microhardness () and some thermodynamical parameters such as Debye temperature (), diffusion constant (), latent heat of melting ( ) etc of PbO–Al2O3–B2O3 glasses doped with rare earth ions viz. Pr3+, Nd3+, Sm3+, Eu3+, Tb3+, Dy3+, Ho3+, Er3+ and Yb3+, ...

Spectroscopic and visible luminescence properties of rare earth ions in lead fluoroborate glasses

Energy Technology Data Exchange (ETDEWEB)

Anjaiah, G. [Department of Physics, Osmania University, Hyderabad 500007 (India); Nayab Rasool, SK. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Kistaiah, P., E-mail: pkistaiah@yahoo.com [Department of Physics, Osmania University, Hyderabad 500007 (India)

2015-03-15

The lanthanide doped lead lithium calcium zinc fluoroborate glasses (LLCZFB:Ln) of composition 20PbF{sub 2}+10Li{sub 2}O+5Cao+5ZnO+59B{sub 2}O{sub 3}+1Ln{sub 2}O{sub 3} (where Ln=Sm, Eu and Dy in mol%) were prepared by conventional melt quench technique. The amorphous nature of these glasses was confirmed by X-ray diffraction studies. The glass transition temperatures (T{sub g}) were studied by DSC analysis. The glass structure and spectroscopic properties were investigated using optical absorption, vibrational and fluorescence spectra. The FT-IR spectra and Raman spectra reveal the presence of BO{sub 3}, BO{sub 4} and non-bridging oxygen's. The Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4, 6) were determined from the spectral intensities of absorption bands. These parameters were used to calculate the radiative parameters such as radiative transition probability (A{sub R}), radiative life time (τ{sub R}) and branching ratio (β{sub r}) for various excited luminescent states of rare earth ions. The visible emission spectra for different rare earth ions were recorded by exciting the samples at different wavelengths and the decay rates for the different rare earth ions were measured. Using the emission spectra, full width half maxima (FWFM), stimulated emission cross section (σ{sup E}{sub p}) were evaluated. The nature of decay profiles of {sup 4}F{sub 9/2}, {sup 4}G{sub 5/2} and {sup 5}D{sub 0} states of Dy, Sm and Eu ions respectively are analyzed. Comparison of luminescence features of these glasses and also with those reported for different glass hosts indicates that the LLCZFB:Dy glass has strong luminescence in the visible region. - Highlights: • LLCZFB:Ln glasses are prepared with Ln: Sm, Eu and Dy. • Glasses are characterized by XRD, FTIR, Raman, absorption and emission spectra. • J–O theory is used to calculate different radiative properties. • Green, yellow and red emissions are observed. • Glasses are useful for the development

Luminescence study on solvation of americium(III), curium(III) and several lanthanide(III) ions in nonaqueous and binary mixed solvents

International Nuclear Information System (INIS)

Kimura, T.; Nagaishi, R.; Kato, Y.; Yoshida, Z.

2001-01-01

The luminescence lifetimes of An(III) and Ln(III) ions [An=Am and Cm; Ln=Nd, Sm, Eu, Tb and Dy] were measured in dimethyl sulfoxide(DMSO), N,N-dimethylformamide(DMF), methanol(MeOH), water and their perdeuterated solvents. Nonradiative decay rates of the ions were in the order of H 2 O > MeOH > DMF > DMSO, indicating that O-H vibration is more effective quencher than C-H, C=O, and S=O vibrations in the solvent molecules. Maximal lifetime ratios τ D /τ H were observed for Eu(III) in H 2 O, for Sm(III) in MeOH and DMF, and for Sm(III) and Dy(III) in DMSO. The solvent composition in the first coordination sphere of Cm(III) and Ln(III) in binary mixed solvents was also studied by measuring the luminescence lifetime. Cm(III) and Ln(III) were preferentially solvated by DMSO in DMSO-H 2 O, by DMF in DMF-H 2 O, and by H 2 O in MeOH-H 2 O over the whole range of the solvent composition. The order of the preferential solvation, i.e., DMSO > DMF > H 2 O > MeOH, correlates with the relative basicity of these solvents. The Gibbs free energy of transfer of ions from water to nonaqueous solvents was further estimated from the degree of the preferential solvation. (orig.)

Syntheses of rare-earth metal oxide nanotubes by the sol-gel method assisted with porous anodic aluminum oxide templates

International Nuclear Information System (INIS)

Kuang Qin; Lin Zhiwei; Lian Wei; Jiang Zhiyuan; Xie Zhaoxiong; Huang Rongbin; Zheng Lansun

2007-01-01

In this paper, we report a versatile synthetic method of ordered rare-earth metal (RE) oxide nanotubes. RE (RE=Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) oxide nanotubes were successfully prepared from corresponding RE nitrate solution via the sol-gel method assisted with porous anodic aluminum oxide (AAO) templates. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM, and X-ray diffraction (XRD) have been employed to characterize the morphology and composition of the as-prepared nanotubes. It is found that as-prepared RE oxides evolve into bamboo-like nanotubes and entirely hollow nanotubes. A new possible formation mechanism of RE oxide nanotubes in the AAO channels is proposed. These high-quantity RE oxide nanotubes are expected to have promising applications in many areas such as luminescent materials, catalysts, magnets, etc. - Graphical abstract: A versatile synthetic method for the preparation of ordered rare-earth (RE) oxide nanotubes is reported, by which RE (RE=Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) oxide nanotubes were successfully prepared from corresponding RE nitrate solution via the sol-gel method assisted with porous anodic aluminum oxide (AAO) templates

[Effect of different excitation monitoring wavelengths on emission spectrum of red long afterglow phosphor Sr3Al2O6 : Eu2+, Dy3+].

Science.gov (United States)

Cui, Cai-e; Li, Jian; Huang, Ping; Liang, Li-ping; Wu, Yin-lan

2012-01-01

The Eu2+ and Dy3+ ion co-doped Sr3Al2O6 phosphor powders with long afterglow were prepared with high temperature solid-state reaction. The phase and the spectra properties of the material were characterized by X-ray diffraction (XRD) and fluorescence spectrophotometer. It was found that the sample is composed of pure Sr3Al2O6 phase. Furthermore, the emission peak of 537 nm under 360 nm excitation and that of 590 nm excited by 468 nm-light were obtained, respectively, and it is more interesting that the emission peaks were at 537 and 590 nm under 394 nm excitation. The effects of different excitation wavelengths on the emission spectrum were explained reasonably by the effect of nephelauxetic effect and crystal field. It revealed that the two types of luminescence with different color were caused by the differences of the center of gravity of the 5d excited state energy level and the split range of 5d energy level.

Study of a new magnetic dipole mode in the heavy deformed nuclei 154Sm, 156Gd, 158Gd, 164Dy, 168Er, and 174Yb by high-resolution electron spectroscopy

International Nuclear Information System (INIS)

Bohle, D.

1985-01-01

By inelastic electron scattering with high energy resolution a new magnetic dipole mode in heavy, deformed nuclei could be detected. For this the nuclei 154 Sm, 156 Gd, 158 Gd, 164 Dy, 168 Er, and 174 Yb were studied at the Darmstadt electron linear accelerator (DALINAC) at small momentum transfer q ≤ 0.6 fm -1 and low excitation energies. A collective magnetic dipole excitation could be discovered in all nuclei at an excitation energy of E x ≅ 66 δA -1/3 MeV whereby δ means the mass deformation. The transition strength extends in the mean to B(M1)↑ ≅ 1.3 μ N 2 . A systematic study of the nucleus 156 Gd yielded hints to a strong fragmentation of the magnetic dipole strength. A comparison of electron scattering, proton scattering, and nuclear resonance fluorescence experiments shows that the new mode is a pure orbital mode. (orig./HSI) [de

Comparative magnetic studies of (Sm, Nd) trichloroacetates and their heteronuclear CuLn2(CCl3COO)8.6H2O systems: structure and spectroscopy of a new type of Eu trichloroacetate

International Nuclear Information System (INIS)

Wojciechowski, W.; Legendziewicz, J.; Puchalska, M.; Ciunik, Z.

2004-01-01

Two series of compounds: heteronuclear CuLn 2 (CCl 3 COO) 8 .6H 2 O (Ln = Nd and Sm) and their simple analogues Ln(CCl 3 COO) 3 .2H 2 O (Ln = Eu, Nd, Sm) were synthesized. New Eu(III) trichloroacetate; Eu(CCl 3 COO) 3 .3H 2 O.CH 3 OH was obtained, its molecular structure was determined by X-ray diffraction and compared with the data of respective systems reported earlier. Magnetization was measured and the susceptibility was derived in the limit of low field. Magnetic susceptibilities were calculated and discussed for series of homo- and hetero-nuclear chloroacetates.Untypical hysteresis was found (two loops) in samarium trichloroacetate. This phenomenon is most probably the effect of flops of spins in magnetic fields of 30,000Oe and very weak (if any) interaction intermediated by weak hydrogen bonding between the chains. A similar magnetic behavior was observed in neodymium carboxylate where the magnetic ordering was observed as a result of Nd-Nd interaction at low temperature (1.6K). For this system, the magnetic moment depends on magnitude of the magnetic field and ferromagnetic ordering appears at low temperatures. The strongest interactions of coupled ions and antiferromagnetic ordering with T N =6.5K were found in CuSm 2 (CCl 3 COO) 8 .6H 2 O single crystals.Heisenberg model was applied in the calculations for three interacting ions located linearly. The following relation was derived: χ M =Ng 2 μ β 2 kT(12)+(12)exp(J 2 /kT)+5exp(J 2 /kT)-exp(1,5J 1 /kT)2+2exp(J 2 /kT)+4exp(J 2 /kT)-exp(1,5J 1 /kT) and applied in calculations of the exchange integrals. Mechanism of the exchange interaction was discussed on the basis of the obtained results.

Provenance studies of Sgraffiato and Late Green Glazed wares from Siraf, Iran

International Nuclear Information System (INIS)

Michel, H.V.; Asaro, F.; Frierman, J.D.

1975-03-01

Results of neutron activation analyses of 23 elements in ceramic archaeological specimens are given. Various wares are divided into the following categories: early Sgraffiato, late Sgraffiato, late Green A, late Green B, and Samarra ware. Results are given on the following elements: Al, Ca, Dy, Mn, Na, K, U, Sm, La, Ti, Lu, Co, Sc, Fe, Cs, Cr, Ni, Eu, Ce, Hf, Ta, Th, and Yb. (JGB)

Miljøundersøgelser ved Kvanefjeldet 2001

DEFF Research Database (Denmark)

Asmund, G.

jordarter' (La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu) Af de mange grundstoffer, der er undersøgt er det kun 'Sjældne jordarter', zirkonium, niobium og thorium, der viser forhøjelser i forhold til baggrundsværdier og samtidigt er stærkt forhøjede i det vand, der siver ud fra minen. Imidlertid fandtes denne...

Fabrication and photoluminescence properties of color-tunable light emitting lanthanide doped GdVO4 hierarchitectures

International Nuclear Information System (INIS)

Amurisana, Bao; Bao, Lihong; Bao, Liang; Tegus, O.

2017-01-01

The flower-like GdVO 4 :Ln 3+ ( Ln 3+ =Eu 3+ , Dy 3+ , Sm 3+ , Tm 3+ ) hierarchitectures have been successfully synthesized on a glass slide substrate through a one-pot hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na 2 H 2 L, where L 4- =(CH 2 COO) 2 N(CH 2 ) 2 N(CH 2 COO) 2 4- ). A high density and ordered flower-like GdVO 4 :Ln 3+ hierarchitectures grew epitaxially on glass substrate. The as-prepared flower-like architectures with the size about 6 μm are constructed by the numerous radially oriented single-crystalline nanorods with the width from 20 nm to 200 nm and the length from 500 nm to 3 μm. The morphologies, the thickness, and the density of as-grown flower clusters can be readily tuned by tailoring the growth time and Na 2 H 2 L/Gd 3+ molar ratio. The possible formation mechanism of flower-like GdVO 4 :Ln 3+ hierarchitectures is discussed on the basis of the results from the controlled experiments under hydrothermal conditions. Because of an energy transfer from vanadate groups to dopants, the flower-like GdVO 4 :Ln 3+ ( Ln 3+ =Eu 3+ , Dy 3+ , Sm 3+ and Tm 3+ ) superstructures showed strong characteristic dominant emissions of the Eu 3+ , Dy 3+ , Sm 3+ and Tm 3+ ions at 617 nm ( 5 D 0 → 7 F 2 , strong red), 575 nm ( 4 F 9/2 → 6 H 13/2 , yellow), 604 nm ( 4 G 5/2 → 6 H 7/2 , orange-red) and 476 nm ( 1 G 4 – 3 H 6 , blue) under ultraviolet excitation, respectively.Further, the emission color of the product can also be tuned by selecting the dopant Ln 3+ with characteristic emissions and varying the concentration ratio of co-doping activators. This approach could be extended to the fabrication of hierarchical structures for other oxide micro/nanomaterials, and may provide a general way to achieve multicolor-tunable emission for many applications.

Guided ion beam and theoretical studies of the bond energy of SmS+

Science.gov (United States)

Armentrout, P. B.; Demireva, Maria; Peterson, Kirk A.

2017-12-01

Previous work has shown that atomic samarium cations react with carbonyl sulfide to form SmS+ + CO in an exothermic and barrierless process. To characterize this reaction further, the bond energy of SmS+ is determined in the present study using guided ion beam tandem mass spectrometry. Reactions of SmS+ with Xe, CO, and O2 are examined. Results for collision-induced dissociation processes with all three molecules along with the endothermicity of the SmS+ + CO → Sm+ + COS exchange reaction are combined to yield D0(Sm+-S) = 3.37 ± 0.20 eV. The CO and O2 reactions also yield a SmSO+ product, with measured endothermicities that indicate D0(SSm+-O) = 3.73 ± 0.16 eV and D0(OSm+-S) = 1.38 ± 0.27 eV. The SmS+ bond energy is compared with theoretical values characterized at several levels of theory, including CCSD(T) complete basis set extrapolations using all-electron basis sets. Multireference configuration interaction calculations with explicit spin-orbit calculations along with composite thermochemistry using the Feller-Peterson-Dixon method and all-electron basis sets were also explored for SmS+, and for comparison, SmO, SmO+, and EuO.

A superdeformed band in {sup 142}Sm

Energy Technology Data Exchange (ETDEWEB)

Hackman, G; Mullins, J M; Kuehner, J A; Prevost, D; Waddington, J C [McMaster Univ., Hamilton, ON (Canada). Dept. of Physics; Galindo-Uribarri, A; Janzen, V P; Radford, D C; Schmeing, N; Ward, D [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.

1992-08-01

Observation of {gamma}-{gamma} coincidences from the reaction {sup 124}Sn({sup 24}Mg,6n){sup 142}Sm at 145 MeV indicates the existence of a rotational band with dynamic moment of inertia J{sup (2)} similar to that of the superdeformed band in the isotone {sup 143}Eu. This result is consistent with calculations predicting superdeformed structures in N = 80, Z {approx} 64 nuclei. (author). 8 refs., 4 figs.

Effect of separated layer thickness on magnetoresistance and magnetic properties of Co/Dy/Co and Ni/Dy/Ni film systems

Science.gov (United States)

Shabelnyk, T. M.; Shutylieva, O. V.; Vorobiov, S. I.; Pazukha, I. M.; Chornous, A. M.

2018-01-01

Co(5 nm)/Dy(tDy)/Co(20 nm)/S and Ni(5 nm)/Dy(tDy)/Ni(20 nm)/S trilayer films are prepared by electron-beam sputtering to investigate the influence of dysprosium layer thickness (tDy) and thermal annealing on the crystal structure, magnetoresistance (MR) and magnetic properties of thin films. The thickness of Dy layer changed in the range from 1 nm to 20 nm. The samples annealed for 20 min at 700 K. Electron diffraction patterns reveal that the as-deposited and annealed systems Co/Dy/Co and Ni/Dy/Ni had fcc-Co + hcp-Dy and fcc-Ni + hcp-Dy phase state, respectively. It is also shown that at the tDy = 15 nm the transition from amorphous to crystalline structures of Dy layer is observed. An increase in the Dy layer thickness results in changes in the MR and magnetic properties of the trilayer systems. It is shown that MR is most thermally stable against annealing to 700 K at tDy = 15 nm for Co/Dy/Co as well as for Ni/Dy/Ni. For tDy = 15 nm the, value of MR for both system increases by two times compared to those of pure ferromagnetic (FM) samples. The coercivity (Bc), remanent (Mr) and saturation (Ms) magnetization of the in-plain magnetization hysteresis loops are related to the Dy layer thickness too. The coercivity depends on the FM materials type and diffusion processes at the layer boundary. Accordingly, Mr and Ms are reduced with tDy increasing before and after annealing for both trilayer systems.

Crystal structure of fluorite-related Ln3SbO7 (Ln=La–Dy) ceramics studied by synchrotron X-ray diffraction and Raman scattering

International Nuclear Information System (INIS)

Siqueira, K.P.F.; Borges, R.M.; Granado, E.; Malard, L.M.; Paula, A.M. de; Moreira, R.L.; Bittar, E.M.; Dias, A.

2013-01-01

Ln 3 SbO 7 (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) ceramics were synthesized by solid-state reaction in optimized conditions of temperature and time to yield single-phase ceramics. The crystal structures of the obtained ceramics were investigated by synchrotron X-ray diffraction, second harmonic generation (SHG) and Raman scattering. All samples exhibited fluorite-type orthorhombic structures with different oxygen arrangements as a function of the ionic radius of the lanthanide metal. For ceramics with the largest ionic radii (La–Nd), the ceramics crystallized into the Cmcm space group, while the ceramics with intermediate and smallest ionic radii (Sm–Dy) exhibited a different crystal structure belonging to the same space group, described under the Ccmm setting. The results from SHG and Raman scattering confirmed these settings and ruled out any possibility for the non-centrosymmetric C222 1 space group describing the structure of the small ionic radii ceramics, solving a recent controversy in the literature. Besides, the Raman modes for all samples are reported for the first time, showing characteristic features for each group of samples. - Graphical abstract: Raman spectrum for La 3 SbO 7 ceramics showing their 22 phonon modes adjusted through Lorentzian lines. According to synchrotron X-ray diffraction and Raman scattering, this material belongs to the space group Cmcm. - Highlights: • Ln 3 SbO 7 ceramics belonging to the space groups Cmcm and Ccmm are synthesized. • SXRD, SHG and Raman scattering confirmed the orthorhombic structures. • Ccmm instead of C222 1 is the correct one based on SHG and Raman data

Fabrication Flexible and Luminescent Nanofibrillated Cellulose Films with Modified SrAl2O4: Eu, Dy Phosphors via Nanoscale Silica and Aminosilane

Directory of Open Access Journals (Sweden)

Longfei Zhang

2018-05-01

Full Text Available Flexible 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO-oxidized nanofibrillated cellulose (ONFC films with long afterglow luminescence containing modified SrAl2O4: Eu2+, Dy3+ (SAOED phosphors were fabricated by a template method. Tetraethyl orthosilicate (TEOS and (3-aminopropyl trimethoxy-silane (APTMS were employed cooperatively to improve the water resistance and compatibility of the SAOED particles in the ONFC suspension. The structure and morphology after modification evidenced the formation of a superior SiO2 layer and coarse amino-compounds on the surface of the phosphors. Homogeneous dispersions containing ONFC and the modified phosphors were prepared and the interface of composite films containing the amino-modified particles showed a more closely packed structure and had less voids at the interface between the cellulose and luminescent particles than that of silica-modified phosphors. The emission spectra for luminescent films showed a slight blue shift (3.2 nm at around 512 nm. Such flexible films with good luminescence, thermal resistance, and mechanical properties can find applications in fields like luminous flexible equipment, night indication, and portable logo or labels.

Moessbauer and channeling experiments on TeSi and SmSi

International Nuclear Information System (INIS)

Kemerink, G.J.; Boerma, D.O.; Waard, H. de; Wit, J.C. de; Drentje, S.A.

1980-01-01

Considerable effort is made to obtain an insight in the structural and electronic properties of ion implanted elemental semiconductors. This research is strongly stimulated by the many applications of semi-conductor devices. We report here on Moessbauer studies of 129 TeSi and 153 SmSi, using the 27.8 keV transition in 129 I and the 103.2 keV transition in 153 Eu, respectively, and on channeling experiments on 128 TeSi and 152 SmSi with a 2 MeV α-beam from the Groningen Van de Graaff generator. In the Moessbauer experiments we used Cu 129 I and EuF 3 .1/2H 2 O as absorber materials. Source and absorber were held at 4.2 K. The implantations were generally done at room temperature with an implantation energy of 100-115 keV. For the Moessbauer and channeling measurements we applied similar Si single crystals and the same implantation and annealing conditions. Crystals with low doses could only be investigated with the Moessbauer effect

Defective muscle basement membrane and lack of M-laminin in the dystrophic dy/dy mouse

DEFF Research Database (Denmark)

Xu, H; Christmas, P; Wu, X R

1994-01-01

-linked Duchenne and Becker muscular dystrophies. We have examined M-laminin expression in mice with autosomal recessive muscular dystrophy caused by the mutation dy. The heavy chain of M-laminin was undetectable in skeletal muscle, heart muscle, and peripheral nerve by immunofluorescence and immunoblotting......M-laminin is a major member of the laminin family of basement membrane proteins. It is prominently expressed in striated muscle and peripheral nerve. M-laminin is deficient in patients with the autosomal recessive Fukuyama congenital muscular dystrophy but is normal in patients with the sex...... tissue from dy/dy mice, suggesting that M-laminin heavy-chain mRNA may be produced at very low levels or is unstable. Information about the chromosomal localization of the M heavy-chain in human and mouse suggests that a mutation in the M-chain gene causes the muscular dystrophy in dy/dy mice. The dy...

Rare earths refining by vacuum sublimation method

International Nuclear Information System (INIS)

Rytus, N.N.

1983-01-01

The process of rare earths refining by the sUblimation; method in high and superhigh oil-free vacuum, is investigated. The method is effective for rare earths obtaining and permits to prepare metal samples with a high value of electric resistance ratio γ=RsUb(298 K)/Rsub(4.2 K). The estimation of general purity is performed for Sm, Eu, Yb, Tm, Dy, Ho, Er and Se

Crystal structure study of new lanthanide silicates with silico-carnotite structure

International Nuclear Information System (INIS)

Piccinelli, F.; Lausi, A.; Speghini, A.; Bettinelli, M.

2012-01-01

The crystal structures of new rare earth-based silicate compounds (Ca 3 Eu 2 Si 3 O 12 , Ca 3 Gd 2 Si 3 O 12 , Ca 3 Dy 2 Si 3 O 12 , Ca 3 Er 2 Si 3 O 12 and Ca 3 Lu 2 Si 3 O 12 ) have been determined using powder X-ray diffraction. From Rietveld refinement calculations on the collected powder patterns we observe a different distribution of the rare earth ions on the three available crystal sites characterized by different coordination numbers, depending on the ionic radius of the rare earth ion. The reasons of the instability of the silico-carnotite structure for lanthanide ions larger than Eu 3+ have been deduced. In addition, in order to detect crystal phase transitions, the powder patterns of Ca 3 Eu 2 Si 3 O 12 and Ca 3 Sm 2 Si 3 O 12 samples have been collected as a function of the temperature (RT-1000 °C range), but no phase transitions have been observed. - Graphical abstract: Synchrotron X-ray diffraction allows us the accurate determination of the RE 3+ ions distribution on the three available crystal sites of the silico-carnotite structure. Highlights: ► The structure of the Ca 3 M 2 Si 3 O 12 (M=Eu, Gd, Dy, Er and Lu) was determined. ► Different distribution of RE 3+ ions on the three available crystal sites was observed. ► The instability of the silico-carnotite structure for RE=La→Sm was discussed.

Effect of mixing RE elements (Nd, Sm, Gd, Eu, Y, Yb) on the RE2BaCuO5/Nd4-2xBa2+2xCu2-xO10-2x phases in RE cuprate high-Tc superconductors

International Nuclear Information System (INIS)

Langhorn, J.B.; Black, M.A.; McGinn, P.J.

1999-01-01

The phases RE 2 BaCuO 5 /RE 4 Ba 2 Cu 2 O 10 phases (where RE is a mixture of Nd, Sm, Gd, Eu, Y and Yb) have been synthesized in an oxygen atmosphere and subsequently characterized. The mixing of RE elements which inherently form the RE 2 BaCuO 5 phase through the peritectic decomposition of REBa 2 Cu 3 O 7-x (RE123) (i.e. Sm, Gd, Eu, Y, Yb), was observed to give homogeneous mixing of the elements in the 211 phase. In contrast it was found that on mixing Nd with other RE elements a mixture of the Nd 4-2x Ba 2+2x Cu 2-x O 10-2x (Nd422) and RE 2 BaCuO 5 (RE211) phases resulted. It was also observed that on mixing Nd with other REs a finite amount of the RE is substituted into the Nd422 phase and Nd into the RE211. (author)

Synthesis, crystal structure, optical and thermal properties of lanthanide hydrogen-polyphosphates Ln[H(PO3)4] (Ln = Tb, Dy, Ho).

Science.gov (United States)

Förg, Katharina; Höppe, Henning A

2015-11-28

Lanthanide hydrogen-polyphosphates Ln[H(PO3)4] (Ln = Tb, Dy, Ho) were synthesised as colourless (Ln = Tb, Dy) and light pink (Ln = Ho) crystalline powders by reaction of Tb4O7/Dy2O3/Ho2O3 with H3PO3 at 380 °C. All compounds crystallise isotypically (P2(1)/c (no. 14), Z = 4, a(Tb) = 1368.24(4) pm, b(Tb) = 710.42(2) pm, c(Tb) = 965.79(3) pm, β(Tb) = 101.200(1)°, 3112 data, 160 parameters, wR2 = 0.062, a(Ho) = 1363.34(5) pm, b(Ho) = 709.24(3) pm, c(Ho) = 959.07(4) pm, β(Ho) = 101.055(1)°, 1607 data, 158 parameters, wR2 = 0.058). The crystal structure comprises two different infinite helical chains of corner-sharing phosphate tetrahedra. In-between these chains the lanthanide ions are located, coordinated by seven oxygen atoms belonging to four different polyphosphate chains. Vibrational, UV/Vis and fluorescence spectra of Ln[H(PO3)4] (Ln = Tb, Dy, Ho) as well as Dy[H(PO3)4]:Ln (Ln = Ce, Eu) and the magnetic and thermal behaviour of Tb[H(PO3)4] are reported.

Moessbauer effect study of hyperfine interaction of /sup 161/Dy and /sup 151/Eu in tungsten bronzes Dysub(0. 18) WO/sub 3/ and Eusub(0. 18) WO/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Kisynska, K

1979-01-01

The Moessbauer technique was used to investigate the hyperfine interaction of /sup 161/Dy and /sup 151/Eu in cubic rare earth tungsten bronzes: Dysub(0.18)WO/sub 3/ and Eusub(0.18)WO/sub 3/. Well resolved hfs spectrum was obtained at 4.2 K for Dysub(0.18)WO/sub 3/. The effective hf field approximation sufficed to interpret the spectrum. The obtained hyperfine interaction parameters were: -g/sub 0/..beta..sub(N)Hsub(eff)=(805+-19) Mc/s and e/sup 2/qQ/sub 0//4 = (506+-56) Mc/s. These results imply that ground doublet of Dy/sup +3/ ion in bronze is a Kramers doublet Vertical Bar+-15/2> with asymmetrical hyperfine tensor Asub(z) non equal to 0, Asub(x) = Asub(y) = 0 and that local crystalline field at RE metal in tungsten bronze at 4.2 K cannot be cubic. From ME absorption spectra of Eusub(0.18)WO/sub 3/ taken at 4.2 K, 78 K and 300 K the values of quadrupole interaction constants for bronze lattice and its temperature dependence were obtained. These data indicate that a phase transition from the high temperature ideal perovskite structure to a distorted one occurs in RE bronzes and that the distortion concerns the nearest tungsten-oxygen environment of RE ion.

Gamma ray induced decomposition of lanthanide nitrates

International Nuclear Information System (INIS)

Joshi, N.G.; Garg, A.N.

1992-01-01

Gamma ray induced decomposition of the lanthanide nitrates, Ln(NO 3 ) 3 .xH 2 O where Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm and Yb has been studied at different absorbed doses up to 600 kGy. G(NO 2 - ) values depend on the absorbed dose and the nature of the outer cation. It has been observed that those lanthanides which exhibit variable valency (Ce and Eu) show lower G-values. An attempt has been made to correlate thermal and radiolytic decomposition processes. (author). 20 refs., 3 figs., 1 tab

Thermoluminescence of rare earth doped BaSO/sub 4/ phosphors and its applications

Energy Technology Data Exchange (ETDEWEB)

Nagpal, J.S.; Varadharajan, G. (Bhabha Atomic Research Centre, Bombay (India). Div. of Radiological Protection)

1982-03-01

Thermoluminescence of synthetic BaSO/sub 4/ samples individually doped with Y, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy and Tm has been studied after ..gamma..- and microwave irradiations. BaSO/sub 4/:Eu has the highest response for ..gamma..-radiation while BaSO/sub 4/:Tb exhibits highest reduction in its ..gamma..-induced TL after exposure to microwave radiation (2425 +- 25 MHz). The reduction depends on the microwave radiant exposure and is independent of the irradiance level in the range 25-200 mW . cm/sup -2/ and hence can be useful for microwave dosimetry.

Rare earth elements determination and distribution patterns in sediments of a polluted marine environment by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Yusof, A.M.

2001-01-01

Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a neutron flux of about 5.0 x 10 12 n x cm -2 x s -1 in a Triga Mark II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area. The shale-normalized REE patterns also showed that LREE in the sediment samples exhibit enrichment relative to HREE particularly, La and Sm showing enrichment compared to the ratios in shale. REE concentrations of 124 μg/g at the surface of sediment collected at two of the three sites were found to decrease to 58 and 95 μg/g, respectively. This was of particular interest when it is used to explain the anomalies occurring in the marine sediment as a result of geochemical processes over a long period of time. Changes in concentrations from surface to bottom of the sediments ratioed to Sm concentrations and the correlation between concentrations of Sm and these elements were also investigated and correlation coefficients were calculated for all REEs and sites. Validation of the method used was done using a Soil-7 SRM. (author)

Lattice dynamical investigation of the Raman and infrared wave numbers and heat capacity properties of the pyrochlores R2Zr2O7 (R = La, Nd, Sm, Eu)

Science.gov (United States)

Nandi, S.; Jana, Y. M.; Gupta, H. C.

2018-04-01

A short-range electrostatic forcefield model has been applied for the first time to investigate the Raman and infrared wave numbers in pyrochlore zirconates R2Zr2O7 (R3+ = La, Nd, Sm, Eu). The calculations of phonons involve five stretching and four bending force constants in the Wilson GF matrix method. The calculated phonon wave numbers are in reasonable agreement with the observed spectra in infrared and Raman excitation zones for all of these isomorphous compounds. The contributions of force constants to each mode show a similar trend of variation for all of these compounds. Furthermore, to validate the established forcefield model, we calculated the standard thermodynamic functions, e.g., molar heat capacity, entropy and enthalpy, and compared the results with the previous experimental data for each compound. Using the derived wave numbers for the acoustic and optical modes, the total phonon contribution to the heat capacity was calculated for all these zirconate compounds. The Schottky heat capacity contributions were also calculated for the magnetic compounds, Nd2Zr2O7, Sm2Zr2O7 and Eu2Zr2O7, taking account of crystal-field level schemes of the lanthanide ions. The derived total heat capacity and the integrated values of molar entropy and molar enthalpy showed satisfactory correlations at low temperatures with the experimental results available in the literature for these compounds. At higher temperatures, the discrepancies may be caused by the anharmonic effects of vibrations, phonon dispersion, distribution of phonon density of states, etc.

Structure–function analysis and genetic interactions of the SmG, SmE, and SmF subunits of the yeast Sm protein ring

Science.gov (United States)

Schwer, Beate; Kruchten, Joshua; Shuman, Stewart

2016-01-01

A seven-subunit Sm protein ring forms a core scaffold of the U1, U2, U4, and U5 snRNPs that direct pre-mRNA splicing. Using human snRNP structures to guide mutagenesis in Saccharomyces cerevisiae, we gained new insights into structure–function relationships of the SmG, SmE, and SmF subunits. An alanine scan of 19 conserved amino acids of these three proteins, comprising the Sm RNA binding sites or inter-subunit interfaces, revealed that, with the exception of Arg74 in SmF, none are essential for yeast growth. Yet, for SmG, SmE, and SmF, as for many components of the yeast spliceosome, the effects of perturbing protein–RNA and protein–protein interactions are masked by built-in functional redundancies of the splicing machine. For example, tests for genetic interactions with non-Sm splicing factors showed that many benign mutations of SmG, SmE, and SmF (and of SmB and SmD3) were synthetically lethal with null alleles of U2 snRNP subunits Lea1 and Msl1. Tests of pairwise combinations of SmG, SmE, SmF, SmB, and SmD3 alleles highlighted the inherent redundancies within the Sm ring, whereby simultaneous mutations of the RNA binding sites of any two of the Sm subunits are lethal. Our results suggest that six intact RNA binding sites in the Sm ring suffice for function but five sites may not. PMID:27417296

Structure-function analysis and genetic interactions of the SmG, SmE, and SmF subunits of the yeast Sm protein ring.

Science.gov (United States)

Schwer, Beate; Kruchten, Joshua; Shuman, Stewart

2016-09-01

A seven-subunit Sm protein ring forms a core scaffold of the U1, U2, U4, and U5 snRNPs that direct pre-mRNA splicing. Using human snRNP structures to guide mutagenesis in Saccharomyces cerevisiae, we gained new insights into structure-function relationships of the SmG, SmE, and SmF subunits. An alanine scan of 19 conserved amino acids of these three proteins, comprising the Sm RNA binding sites or inter-subunit interfaces, revealed that, with the exception of Arg74 in SmF, none are essential for yeast growth. Yet, for SmG, SmE, and SmF, as for many components of the yeast spliceosome, the effects of perturbing protein-RNA and protein-protein interactions are masked by built-in functional redundancies of the splicing machine. For example, tests for genetic interactions with non-Sm splicing factors showed that many benign mutations of SmG, SmE, and SmF (and of SmB and SmD3) were synthetically lethal with null alleles of U2 snRNP subunits Lea1 and Msl1. Tests of pairwise combinations of SmG, SmE, SmF, SmB, and SmD3 alleles highlighted the inherent redundancies within the Sm ring, whereby simultaneous mutations of the RNA binding sites of any two of the Sm subunits are lethal. Our results suggest that six intact RNA binding sites in the Sm ring suffice for function but five sites may not. © 2016 Schwer et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Synthesis, characterization and luminescent properties of lanthanide complexes with an unsymmetrical tripodal ligand

Energy Technology Data Exchange (ETDEWEB)

Yan Zhenzhong [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tang Yu [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)], E-mail: tangyu@lzu.edu.cn; Liu Weisheng; Tan Minyu [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2008-09-15

Solid complexes of lanthanide nitrates with a new unsymmetrical tripodal ligand, bis[(2'-benzylaminoformyl)phenoxyl)ethyl](ethyl)amine (L) have been synthesized and characterized by elemental analysis, infrared spectra and molar conductivity measurements. At the same time, the luminescent properties of the Sm(III), Eu(III), Tb(III) and Dy(III) nitrate complexes in solid state were also investigated. Under the excitation of UV light, these complexes exhibited characteristic emission of central metal ions.

New orthorhombic derivative of CaCu{sub 5}-type structure: RNi{sub 4}Si compounds (R=Y, La, Ce, Sm, Gd–Ho), crystal structure and some magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India)

2013-12-15

The crystal structure of new YNi{sub 4}Si-type RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds has been established using powder X-ray diffraction. The YNi{sub 4}Si structure is a new structure type, which is orthorhombic derivative of CaCu{sub 5}-type structure (space group Cmmm N 65, oC12). GdNi{sub 4}Si and DyNi{sub 4}Si compounds order ferromagnetically at 25 and 19 K, respectively whereas YNi{sub 4}Si shows antiferromagnetic nature. At 15 K, DyNi{sub 4}Si shows second antiferromagnetic-like transition. The magnetic moment of GdNi{sub 4}Si at 5 K in 50 kOe field is ∼7.2 μ{sub B}/f.u. suggesting a completely ordered ferromagnetic state. The magnetocaloric effect of GdNi{sub 4}Si is calculated in terms of isothermal magnetic entropy change and it reaches the maximum value of −12.8 J/kg K for a field change of 50 kOe near T{sub C} ∼25 K. - Graphical abstract: The RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds crystallize in new YNi{sub 4}Si-type structure which is orthorhombic derivative of the basic CaCu{sub 5}-type structure. GdNi{sub 4}Si and DyNi{sub 4}Si compounds show the ferromagnetic-like ordering, whereas.YNi{sub 4}Si has the antiferromagnetic nature. The GdNi{sub 4}Si demonstrates the big magnetocaloric effect near temperature of ferromagnetic ordering. The relationship between initial CaCu{sub 5}-type DyNi{sub 5} and YNi{sub 4}Si-type DyNi{sub 4}Si lattices.

Implantation sites of Ce and Gd in diamond

CERN Document Server

Bharuth-Ram, K; Hofsäss, H C; Ronning, C; Dietrich, M

2002-01-01

The implantation sites of rare earth (RE) probes /sup 141/Ce (t/sub 1 /2/=32 d) and /sup 149/Gd (t/sub 1/2/=9.28 d) in diamond have been investigated using the emission channeling (EC) technique. Parent isotopes /sup 141/Cs and /sup 149/Dy were implanted into type IIa, diamond samples at an energy of 60 keV at the online isotope separator ISOLDE at CERN. /sup 141/Cs decays through the chain /sup 141/Cs-/sup 141/Ba-/sup 141/La-/sup 141/Ce-/sup 141/ Pr. EC measurements were made on the 102 keV conversion electrons emitted in the decay of /sup 141/Pr to its ground state. The decay of /sup 149 /Dy follows the chain /sup 149/Dy-/sup 149/Tb-/sup 149/Gd-/sup 149 /Eu-/sup 149/Sm. EC measurements were made on the 101 keV electrons emitted in the decay of /sup 149/Eu. Two-dimensional channeling patterns of the conversion electrons were obtained along and axial directions by raster scans with a Si surface barrier detector. Comparison of the observed patterns with simulated spectra show that in diamond 45-50% of the RE...

Influence of Dy in solid solution on the degradation behavior of binary Mg-Dy alloys in cell culture medium.

Science.gov (United States)

Yang, Lei; Ma, Liangong; Huang, Yuanding; Feyerabend, Frank; Blawert, Carsten; Höche, Daniel; Willumeit-Römer, Regine; Zhang, Erlin; Kainer, Karl Ulrich; Hort, Norbert

2017-06-01

Rare earth element Dy is one of the promising alloying elements for magnesium alloy as biodegradable implants. To understand the effect of Dy in solid solution on the degradation of Mg-Dy alloys in simulated physiological conditions, the present work studied the microstructure and degradation behavior of Mg-Dy alloys in cell culture medium. It is found the corrosion resistance enhances with the increase of Dy content in solid solution in Mg. This can be attributed to the formation of a relatively more corrosion resistant Dy-enriched film which decreases the anodic dissolution of Mg. Copyright © 2017 Elsevier B.V. All rights reserved.

Rotational and translational distortions of the crystal structure of the Sr2HrRuO6 (Hr = Ho, Dy, Gd, Eu) complex perovskites

International Nuclear Information System (INIS)

Triana, C.A.; Landínez Téllez, D.A.; Roa-Rojas, J.

2013-01-01

Sr 2 HrRuO 6 (Hr = Ho, Dy, Gd, Eu) complex perovskites were synthesized through the high-temperature solid-state reaction method, and their crystal structures were analyzed in detail as a function of the Hr-cation ionic radius. Results of powder XRD pattern measurement and Rietveld analysis of the experimental profiles show that the Sr 2 HrRuO 6 compounds crystallize in a monoclinic distorted perovskite-like structure, P2 1 /n (#14) space group, where the unit cell parameters are related to the primitive unit cell a p by a≈√(2)a p , b≈√(2)a p and c ≈ 2a p . The structures show an alternate distribution of the Ru 5+ (2d: 0.5, 0, 0) and Hr 3+ (2c: 0, 0.5, 0) making up RuO 6 and HrO 6 octahedra alternatively arranged in two interleaving fcc sublattices, where the O(1), O(2), and O(3) ions are localized at the corner of the octahedral, while the Sr 2+ is located at the A-site, occupying the cavities built by the corner-sharing octahedra with Wyckoff position 4e. Due to the existence of mismatched ionic sizes between the ionic radii of the Sr 2 HrRuO 6 compounds, the HrO 6 and RuO 6 octahedra are constrained to tilting around the [111] c , [001] c , and [110] c cubic directions so as to optimize the Sr–O inter-atomic bond lengths, tending to rotate the structure in order to fix the Ru 5+ and Hr 3+ ions on the M′ and M″ sites of the complex perovskites. The cell parameters a, b, and c, the inter-atomic bond angles, the inter-atomic bond lengths, and the tilting angles increase as the Hr-cation ionic radius increases. The mismatch that exists in the Sr 2 HrRuO 6 ionic radius produces a large distortion from the ideal cubic symmetry. The pure perovskite-like phase of Sr 2 HrRuO 6 is thermodynamically and kinetically stable at high temperatures above 1420 K, where it is entirely governed by the average size of the Hr 3+ and Ru 5+ cations. Highlights: ► Crystal structure of Sr 2 HrRuO 6 (Hr = Ho, Dy, Gd, Eu) as a function of Hr ionic radius. ► XRD

Effect of rare-earth ion size on local electron structure in RBa2Cu3O7-δ (R = Tm, Dy, Gd, Eu, Nd and Y) superconductors: A positron study

International Nuclear Information System (INIS)

Chen Zhenping; Zhang Jincang; Su Yuling; Xue Yuncai; Cao Shixun

2006-01-01

The effects of rare-earth ionic size on the local electron structure, lattice parameters and superconductivity have been investigated by positron annihilation technique (PAT) and related experiments for RBa 2 Cu 3 O 7-δ (R = Tm, Dy, Gd, Eu, Nd and Y) superconductors. The local electron density n e is evaluated as a function of the rare-earth radius. The results show that both the bulk-lifetime τ B and the defect lifetime τ 2 increase with increasing rare-earth ionic radius, while the local electron density n e decrease with increasing rare-earth ionic radius. These results prove that the changes of n e , the degree of orthorhombic distortion and the coupling between the Cu-O chains and the CuO 2 planes all have an effect on the superconductivity of RBa 2 Cu 3 O 7-δ systems

Isolated centres versus defect associates in Sm3+-doped CeO2: a spectroscopic investigation

International Nuclear Information System (INIS)

Tiseanu, Carmen; Avram, Daniel; Cojocaru, Bogdan; Parvulescu, Vasile I; Vela-Gonzalez, Andrea V; Sanchez-Dominguez, Margarita

2013-01-01

The interactions between Sm 3+ and oxygen vacancies in CeO 2 are probed by the use of tuneable laser excited time-resolved photoluminescence and Raman spectroscopies. It is found that Sm 3+ (with doping concentrations of 0.1, 0.3, 1 and 5 wt%) substitutes largely for Ce 4+ in sites with cubic symmetry and the corresponding emission is sensitized via the Ce 4+ –O 2− charge-transfer band of CeO 2 . It is established from the photoluminescence spectra measured at long delay after the laser pulse that the local environment around cubic Sm 3+ centres is not changed with concentration and ceria size. In addition to cubic symmetry Sm 3+ centres, low-symmetry Sm 3+ centres tentatively assigned to the Sm 3+ –oxygen vacancy associates of nearest-neighbour type are also observed. Their emission is preferentially excited via the weak f–f absorption transitions of Sm 3+ . A relatively strong concentration-induced quenching of Sm 3+ emission was inferred from the decrease in the average emission lifetimes from 2.1 ms (0.1 wt%) to 0.87 ms (5 wt%). The local environments of Sm 3+ and Eu 3+ in CeO 2 are also compared on the basis of their emission spectra and decays. (paper)

Magnetic properties of Dy/Zr multilayers

International Nuclear Information System (INIS)

Luche, M.C.; Boyer, P.

1992-01-01

[Dy(xA)/Zr(30A)] n superlattices (x ≤ 30), were evaporated under ultra-high vacuum on Si(100) substrates. Magnetization measurements indicate that the antiferromagnetic transition occurring at 178K in bulk Dy is suppressed in the multilayers. This phenomenon is attributed to magnetoelastic effects induced by strains at Zr/Dy interfaces. A perpendicular magnetic anisotropy takes place for x ≤ 15. However, the magnetic anisotropy is found to depend markedly on the technique used for Dy deposition. (author). 11 refs., 4 figs

Magnetooptic effects and Auger electron spectroscopy of two-layer NiFe-Dy and Fe-Dy films with nonuniform layers

International Nuclear Information System (INIS)

Ehdel'man, I.S.; Markov, V.V.; Khudyakov, A.E.; Ivantsov, R.D.; Bondarenko, G.V.; Ovchinnikov, S.G.; Kesler, V.G.; Parshin, A.S.; Ronzhin, I.P.

2001-01-01

Magneto-optical effects (magnetic circular dichroism and meridional Kerr effect) and element distribution with layer thickness in two-layer NiFe-Dy and Fe-Dy films, prepared by thermal sputtering of component in ultrahigh vacuum, are investigated. It is shown, that Dy in a two-layer film in the temperature range of 80-300 K makes constant contributions to both effects investigated which are approximately equal to the values of the effects observed in an isolated Dy film only at temperatures below the temperature T c of Dy transition into a ferromagnetic state (T c ∼ 100 K for the films under study). This behaviour of magneto-optical effects is assumed to be due to the influence of a NiFe layer spin system on magnetic state of a Dy layer, this influence is enhanced by the deep penetration of Ni and Fe ions into Dy layer as it follows from the data obtained using Auger electron spectroscopy [ru

High coercivity rare earth-transition metal magnets

International Nuclear Information System (INIS)

Croat, J.J.

1982-01-01

Ferromagnetic compositions having intrinsic magnetic coercivities at room temperature of at least 1,000 Oersteds are formed by the controlled quenching of molten rare earth-transition metal alloys. Hard magnets may be inexpensively formed from the lower atomic weight lanthanide elements and iron. The preferable compositions lie within: at least one of Fe, Ni, Co; 20 - 70 atomic percent: at least one of Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Y; 80 - 30 atomic percent. (author)

n-aminobenzoates of rare earths

International Nuclear Information System (INIS)

Efremova, G.I.; Buchkova, R.T.; Lapitskaya, A.V.; Pirkes, S.B.

1977-01-01

N-aminobenzoates of r.e.e. have been synthesized. Their composition corresponds to the general formula Me(C 6 H 4 NH 2 COO) 3 xnH 2 O, where Me stands for La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; n=1.2. The compounds obtained are identified by chemical analysis and roentgenographically. Their solubility products, which are values of the order of 10 -9 -10 -10 , are determined

Relaxor-ferroelectric BaLnZT (Ln = La, Nd, Sm, Eu, and Sc) ceramics for actuator and energy storage application

Science.gov (United States)

Ghosh, Sarit K.; Mallick, Kaushik; Tiwari, B.; Sinha, E.; Rout, S. K.

2018-01-01

Lead free ceramics Ba1-x Ln2x/3Zr0.3Ti0.7O3 (Ln = La, Nd, Sm, Eu and Sc), x = 0.02-0.10 are investigated for electrostrictive effect and energy storage properties in the proximity of relaxor-paraelectric phase boundary. Relaxor phase evidence from slim hysteresis loop and low remnant polarization are the key parameters responsible for improve the electrostrictive effect and energy storage properties simultaneously. With increase in rare earth content negative strain disappeared and almost hysteresis free strain is achieved. Strain-hysteresis profile in term of S-E, S-E 2 and S-P 2 is used to analyze the electrostrictive behavior of these ceramics. An average strain (S%) ˜ 0.03%, is accomplished at initial concentrations of x = 0.02-0.04 and electrostrictive coefficients (Q 11, and M 11) as well as the energy storage density is improved by a factor of 1.2 and 2.6 respectively when compare with pure (x = 0.0) ceramic. Above x ≥ 0.06, all compositions show a stable behavior which suggested the possibilities of these relaxor ceramics towards high precision actuators and energy storage application.

Preparation of the Nanostructured Radioisotope Metallic Oxide by Neutron Irradiation for Use as Radiotracers

Directory of Open Access Journals (Sweden)

Sang-Ei Seo

2017-10-01

Full Text Available Metallic oxides manganese dioxide (MnO2, samarium oxide (Sm2O3, and dysprosium oxide (Dy2O3 with nanorod-like structures were synthesized by the hydrothermal synthesis method, respectively. Subsequently, the nanostructured radioisotopes MnO2 with Mn-56, Sm2O3 with Sm-153, and Dy2O3 with Dy-165 were prepared by neutron irradiation from the HANARO research reactor, respectively. The three different elements, Mn, Sm, and Dy, were selected as radiotracers because these elements can be easily gamma-activated from neutrons (activation limits: 1 picogram (Dy, 1–10 picogram (Mn, 10–100 picogram (Sm. Furthermore, the synthesized radioisotopes can be used as radiotracers in Prompt Gamma Neutron Activation Analysis as the rare earth metals Dy and Sm were not present in the Korean environment. The successful synthesis of the radioisotope metallic oxides was confirmed by Transmission Electron Microscopy (TEM, Energy Dispersive X-ray Spectrometry (EDS, X-ray Diffraction (XRD analysis, and gamma spectroscopy analysis. The synthesized nanostructured radioisotope metallic oxides may be used as radiotracers in scientific, environmental, engineering, and industrial fields.

Effects of 3d-4f magnetic exchange interactions on the dynamics of the magnetization of Dy(III)-M(II)-Dy(III) trinuclear clusters.

Science.gov (United States)

Pointillart, Fabrice; Bernot, Kevin; Sessoli, Roberta; Gatteschi, Dante

2007-01-01

[{Dy(hfac)(3)}(2){Fe(bpca)(2)}] x CHCl(3) ([Dy(2)Fe]) and [{Dy(hfac)(3)}(2){Ni(bpca)(2)}]CHCl(3) ([Dy(2)Ni]) (in which hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate and bpca(-)=bis(2-pyridylcarbonyl)amine anion) were synthesized and characterized. Single-crystal X-ray diffraction shows that [Dy(2)Fe] and [Dy(2)Ni] are linear trinuclear complexes. Static magnetic susceptibility measurements reveal a weak ferromagnetic exchange interaction between Ni(II) and Dy(III) ions in [Dy(2)Ni], whereas the use of the diamagnetic Fe(II) ion leads to the absence of magnetic exchange interaction in [Dy(2)Fe]. Dynamic susceptibility measurements show a thermally activated behavior with the energy barrier of 9.7 and 4.9 K for the [Dy(2)Fe] and [Dy(2)Ni] complexes, respectively. A surprising negative effect of the ferromagnetic exchange interaction has been found and has been attributed to the structural conformation of these trinuclear complexes.

Rare earth element patterns in nigerian coals

International Nuclear Information System (INIS)

Ewa, I.O.B.; Elegba, S.B.

1996-01-01

Rare Earth Elements (REE's) retain group coherence in their environment and are therefore useful geochemical markers. We report the pattern of ten REE's (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Lu) determined by Instrumental Neutron Activation Analysis (INAA) for coals obtained from eight mines in Nigeria, namely, Okaba, Enugu, Ogbete, Onyeama, Gombe, Lafia, Asaba and Afikpo. Our results show the existence of fractionations with the highest index of 13.19 for Lafia coal, depletion in HREE, negative Eu anomaly for most of the coals, REE patterns that are consistent with chondritic trends; prominent (Eu/Eu * ) cn for Okaba and Gombe coals. Variations in geochemical data observed could suggest strong departures from band metamorphism during the coalification events of the Benue Trough geosynclines, where the coal deposits are all located. (author) 14 refs., 2 figs., 3 tabs

Rare earth elements in the Pacific and Atlantic Oceans. [Pr, Tb, Ho, Tm, Lu, La, Nd, Sm, Eu, Gd, Yb, Ce

Energy Technology Data Exchange (ETDEWEB)

Baar, H J.W. de; Bacon, M P; Brewer, P G; Bruland, K W

1985-09-01

The first profiles of Pr, Tb, Ho, Tm and Lu in the Pacific Ocean, as well as profiles of La, Ce, Nd, Sm, Eu, Gd and Yb are reported. Concentrations of REE (except Ce) in the deep water are two to three times higher than those observed in the deep Atlantic Ocean. Surface water concentrations are typically lower than in the Atlantic Ocean, especially for the heavier elements Ho,Tm,Yb and Lu. Cerium is strongly depleted in the Pacific water column, but less so in the oxygen minimum zone. The distribution of the REE group is consistent with two simultaneous processes: (1) cycling similar to that of opal and calcium carbonate, and (2) adsorptive scavenging by settling particles and possibly by uptake at ocean boundaries. However, the first process can probably not be sustained by the low REE contents of shells, unless additional adsorption on surfaces is invoked. The second process, adsorptive scavenging, largely controls the oceanic distribution and typical seawater pattern of the rare earths. (author).

Standard light source utilizing spontaneous radiation

International Nuclear Information System (INIS)

Yamamoto, O.; Takenaga, M.; Tsujimoto, Y.

1975-01-01

A standard light source is described utilizing spontaneous radiation made by mixing a fluorescent substance LnVO 4 :X (wherein Ln is Y or Gd, and X is Dy or Eu) with a radioactive substance containing a radioactive isotope which is less in the degree of temperature variation of the intensity of emitted light and excellent in stability. Particularly when used in a light-receiving device having photomultiplier tubes, the said light source emits light quite similar to that of a thermoluminescent substance such as CaSO 4 :X (wherein X is Im, Dy, Sm or Mn), LiF or Mg 2 SiO 4 :Tb, and is excellent as a calibration high-stability standard light source for use in the above-mentioned light-receiving device. (auth)

TL characterization of Ag co-doped SrSO{sub 4}:Eu phosphor for gamma dosimetry applications

Energy Technology Data Exchange (ETDEWEB)

Jayasudha, S., E-mail: jsnair.india@gmail.com [Mahatma Gandhi College, Pattom Palace P.O., Thiruvananthapuram 695004 (India); Madhukumar, K.; Nair, C.M.K.; Nair, Resmi G.; Anandakumar, V.M. [Mahatma Gandhi College, Pattom Palace P.O., Thiruvananthapuram 695004 (India); Elias, T.S. [State Institute of Cancer Research, Medical College P.O., Thiruvananthapuram 695011 (India); Rajesh, S. [Campus Universitario de Santiago, Aveiro (Portugal)

2017-04-15

High temperature thermoluminescence (TL) emissions and improvement in fading due to the co-doping ofr Ag in the SrSO{sub 4}:Eu phosphor synthesized through chemical precipitation technique when subjected to γ-excitation is discussed. The dopant concentrations were tuned for optimum TL sensitivity. Preliminary crystallographic and structural studies of the phosphors were done using PXRD, SEM, and TEM. The phosphor has a single phase orthorhombic lattice structure and the crystallites are found to be nanostructured. The presence of dopants in the host matrix is established through EDS and ICP-AES studies. The TL glow curve shows a single intense emission at 314 ├ó┬ü┬░C under γ- exposure of dose 1 Gy, which is given from a {sup 60}Co build-up. The dosimetric properties such as sensitivity, dose dependence, fading and reusability of SrSO{sub 4}:Eu,Ag phosphor were also studied. It is observed that co-doping with Ag improves the fading rate of the SrSO{sub 4}:Eu phosphor by about 5%. Even though the luminescence intensity is found to be less than that of SrSO{sub 4}:Eu phosphor, the Ag co-doped phosphor becomes significant owing to its improved fading rate and high temperature afterglow. The gamma sensitivity of the SrSO{sub 4}:Eu,Ag(0.5,0.5 mol%) phosphor is compared to that of the standard CaSO{sub 4}:Dy TLD phosphor. The TL kinetic parameters were calculated using IR, Chen's peak shape method and verified by the theoretical fit using GCD functions. - Highlights: • A High temperature TL emission is observed for the SrSO{sub 4}:Eu,Ag phosphor. • TL intensity is 10 times higher than that of standard CaSO{sub 4}:Dy. • Fading rate of SrSO{sub 4}:Eu phosphor is improved by 5% with Ag co-doping. • Linear dose response in the range 10mGy-10Gy. • t .

Isothermal sections at 500 deg C of the Dy-V-Al and Dy-Cr-Al systems in the aluminium rich regions

International Nuclear Information System (INIS)

Rykhal', R.M.; Zarechnyuk, O.S.; Mats'kiv, O.P.

1979-01-01

X-ray diffraction and microscopic analyses have been used to investigate the ternary system dysprosium-vanadium-aluminium in the aluminium rich region. In the system Dy-V-Al two ternary compounds have been found: DyV 2 Al 20 (cubic structure, CeCr 2 Al 20 type, a=14.54 A and approximately DyVAl 8 (hexagonal crystal system, structure unknown, a=10.86, c=17.71 A, c/a=1.631). In the system dysprosium-chromium-aluminium three ternary compounds have been found: DyCr 2 Al 20 (cubic structure, CeCr 2 Al 20 type, a=14.39), approximately equal to DyCrAl 8 ) hexagonal crystal system, structure type unkown a=10.75, c=17.60 A, c/a=1.637) and DyCr 4 Al 8 (tetragonal structure, CeMn 4 Al 8 type, a=8.87, c=5.04 A, c/a=0.568). Isothermal sections of the systems Dy-V-Al and Dy-Cr-Al have been plotted at 500 deg C

New lanthanide hydrogen phosphites LnH (P03H)2 2H20

International Nuclear Information System (INIS)

Durand, J.; Tijani, N.; Cot, L.; Loukili, M.; Rafiq, M.

1988-01-01

LnH ((P0 3 H) 2 2H 2 0 is prepared from lanthanide oxide and phosphorous acid with Ln = La, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er or Tm. By thermal gravimetric analysis LnH (P0 3 H) 2 and LnH 2 P 2 0 5 (P0 3 H) 2 are obtained. The three salts are orthorhombic. Parameters and space groups are given for the three salts of each lanthanide. 4 tabs., 13 refs

High coercivity rare earth-transition metal magnets

International Nuclear Information System (INIS)

Croat, J.J.

1982-01-01

Ferromagnetic compositions having intrinsic magnetic coercivities at room temperature of at least 1,000 Oersteds are formed by the controlled quenching of molten rare earth -transition metal alloys. Hard magnets may be inexpensively formed from the lower atomic weight lanthanide elements and iron. The preferable compositions lie within: at least one of Fe, Ni, Co (20 to 70 atomic percent); and at least one of Ce, Pr, Na, Sm, Eu, Tb, Dy, Ho, Er, Tm, Y (80 to 30 atomic percent). (author)

Positive/negative liquid secondary ion mass spectrometry of Ln-EDTA (1:1) complexes. Formation of molecular ion adducts with neutral species of the matrix or Ln-EDTA

International Nuclear Information System (INIS)

Plaziak, A.S.; Lis, S.; Elbanowski, M.

1992-01-01

The mass spectra of 1:1 complexes of EDTA with lanthanide cations (Ln=Sm, Eu, Gd, Tb or Dy) upon positive/negative LSIMS are presented. In glycerol used as a matrix, adduct-ions such as [M+H] + , [M+H+nGly] + , [2M+H] + , [2M+H+Gly] + (positive LSIMS) or [M-H] - , [M-H+nGly] - , [2M-H] - , [2M-H+Gly] - (negative LSIMS), where n=1-3, are formed. Reactions leading to the formation of adduct-ions are suggested. (authors)

Epithermal neutron activation analysis investigation of Clarion-Clipperton abyssal plane clay and polymetallic micronodules.

Science.gov (United States)

Duliu, O G; Cristache, C I; Culicovc, O A; Frontasyeva, M V; Szobotca, S A; Toma, M

2009-05-01

The content of seven major (Na, Al, Cl, Mn, K, Ca, Ti, Fe) and 30 trace (Sc, V, Cr, Ni, Co, Zn, Cu, As, Sr, Rb, Zr, Mo, Sn, In, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Dy, Yb, Hf, Ta, W, Th, U) elements determined by INAA in 13 samples of abyssal clay and two samples of micronodules collected from the North pacific Ocean Clarion-Clipperton abyssal plane is presented and discussed with respect to some rocks models.

Epithermal neutron activation analysis investigation of Clarion-Clipperton abyssal plane clay and polymetallic micronodules

International Nuclear Information System (INIS)

Duliu, O.G.; Cristache, C.I.; Culicovc, O.A.; Frontasyeva, M.V.; Szobotca, S.A.; Toma, M.

2009-01-01

The content of seven major (Na, Al, Cl, Mn, K, Ca, Ti, Fe) and 30 trace (Sc, V, Cr, Ni, Co, Zn, Cu, As, Sr, Rb, Zr, Mo, Sn, In, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Dy, Yb, Hf, Ta, W, Th, U) elements determined by INAA in 13 samples of abyssal clay and two samples of micronodules collected from the North pacific Ocean Clarion-Clipperton abyssal plane is presented and discussed with respect to some rocks models.

Epithermal neutron activation analysis investigation of Clarion-Clipperton abyssal plane clay and polymetallic micronodules

Energy Technology Data Exchange (ETDEWEB)

Duliu, O.G. [University of Bucharest, Department of Atomic and Nuclear Physics, P.O. Box MG-11, 077125 Magurele, Ilfov (Romania)], E-mail: duliu@b.astral.ro; Cristache, C.I. [National Institute of Research and Development for Physics and Nuclear Engineering ' Horia-Hulubei' , P.O. Box MG-6, 077125 Magurele, Ilfov (Romania)], E-mail: ocarmen@ifin.nipne.ro; Culicovc, O.A. [Joint Institute of Nuclear Research, 6, Joliot Curie str., 141980 Dubna (Russian Federation)], E-mail: otilia_culicov@yahoo.com; Frontasyeva, M.V. [Joint Institute of Nuclear Research, 6, Joliot Curie str., 141980 Dubna (Russian Federation)], E-mail: marina@nf.jinr.ru; Szobotca, S.A. [National Institute of Geoecology and Marine Geology, 34 Dimitrie Onciul str., 024504 Bucharest (Romania)], E-mail: szobi@geoecomar.ro; Toma, M. [National Institute of Research and Development for Physics and Nuclear Engineering ' Horia-Hulubei' , P.O. Box MG-6, 077125 Magurele, Ilfov (Romania)

2009-05-15

The content of seven major (Na, Al, Cl, Mn, K, Ca, Ti, Fe) and 30 trace (Sc, V, Cr, Ni, Co, Zn, Cu, As, Sr, Rb, Zr, Mo, Sn, In, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Dy, Yb, Hf, Ta, W, Th, U) elements determined by INAA in 13 samples of abyssal clay and two samples of micronodules collected from the North pacific Ocean Clarion-Clipperton abyssal plane is presented and discussed with respect to some rocks models.

Effect of chelate ring sizes and their substitution on intensities of hypersensitive transitions of lanthanoids (Ln(III)) ions and j (total quantum number profiles)

International Nuclear Information System (INIS)

Dubey, J.; Pandey, P.; Yadav, A.; Limaye, S.N.

1998-01-01

Full text: Electronic spectral studies of Pr(III), Nd(III), Sm(III) Dy(III), Eu(III) and Tm(III) complexes with some aliphatic and aromatic O-O donor ligands viz., Glycolic (gly), Malonic (main) Succinic (suc), Glutaric (glut), Salicylic (sal), Phthalic acids and Catechol (cat) having varied chelate ring sizes and different substitutions as side chains have been carried out with a view to study the effect of chelate ring sizes on the intensities of hypersensitive and pseudo-hypersensitive transitions in lanthanoids. The intensities of these HST transitions have also been correlated with the total quantum number (J) of the lanthanoid metal ions in order to seek a probable mechanism for the phenomenon hypersensitivity. A comparison of the spectral and nephelauxetic parameters for Pr(III), Nd(III), Sm(III) with Dy(III) Er(III) and Tm(III) exhibit a variation in the bonding pattern from electrostatic to covalo-electrostatic from pre-Gd elements to post-Gd elements. The J-(total) quantum number profiles of the oscillator strength values for the specific HST transitions have also been examined

Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln==Sm, Eu, Gd) and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln==Tb, Dy, Ho)

Energy Technology Data Exchange (ETDEWEB)

Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian, E-mail: jiadingxian@suda.edu.cn

2013-10-15

Solvothermal reactions of Ln{sub 2}O{sub 3}, As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln{sub 2}O{sub 3} oxides were converted to [Ln(dien){sub 2}]{sup 3+} complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS{sub 4} unit. In 1−3, the AsS{sub 4} units interconnect the [Ln(dien){sub 2}]{sup 3+} cations via Ln−S bonds as tridentate μ-1κ,2κ{sup 2}-AsS{sub 4} bridging ligands, resulting in the neutral coordination polymers [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln1). In 4−6, the AsS{sub 4} units coordinate with the Ln{sup 3+} ion of [Ln(dien){sub 2}]{sup 3+} as 1κ{sup 2}-AsS{sub 4} chelating ligands to form neutral coordination compounds [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln2). The Ln{sup 3+} ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln{sup 3+} ions. Optical absorption spectra showed that 1−6 have potential use as semiconductors with the band gaps in the range 2.18−3.21 eV. - Graphical abstract: Two types of Ln-thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] were prepared by solvothermal methods and the soft Lewis basic AsS{sub 4}{sup 3–} ligand to Ln(III) centers with polyamine co-ligand was obtained. Display Omitted - Highlights: • Lanthanide thioarsenates were prepared by solvothermal methods. • The soft Lewis basic AsS{sub 4} ligand coordinate Ln{sup 3+} ions with coexistence polyamine ligands. • Two structural types of Ln-thioarsenates with structural turnover at Tb were obtained along Ln series. • The Ln-thioarsenates are potential semiconductors

Phase equilibria in Dy-Cu-Al system at 500 deg C

International Nuclear Information System (INIS)

Kuz'ma, Yu.B.; Milyan, V.V.

1989-01-01

Using the methods of X-ray diffraction analysis a diagram of phase equilibria in Dy-Cu-Al system at 500 deg C is plotted. Boundaries of solid solutions on the basis of DyCu 2 , DyCu and DyAl 2 compounds are determined and homogeneity regions of ternary compounds Dy 2 (Cu, Al) 7 and Dy(CuAl) 5 are ascertained. Compounds DyCuAl 3 , Dy 4 Cu 4 Al 11 and Dy 5 Cu 6 Al 9 have been detected for the first time

Phase transitions of rare earth compounds during immobilization by foamed corundum

International Nuclear Information System (INIS)

Potemkina, T.I.; Zakharov, M.A.; Plotnikova, T.E.

1992-01-01

Expansion of work on the environmentally safe handling of radioactive materials has become very important in recent years. The proposed method for immobilizing radionuclides by injection into a porous matrix and subsequent fixation has a definite advantage over other techniques, because of its simplicity and low cost. This raises a number of problems that require careful study. The authors can distinguish the following: choice of porous matrix materials; thermal decomposition of nitrates directly in the matrix itself, which determines the minimum firing temperature; behavior and properties of oxides produced in nitrate decomposition; conditions for compound formation between injected solutions and matrix material; processes occurring during immobilizer storage. The rare earth nitrate series can be divided into two groups on the basis of behavior during thermal decomposition: the elements preceding and following Gd. The first group includes La, Pr, And Eu, for which decomposition begins simultaneously with conclusion of dehydration; the second includes Dy, Tb, and Yb, for which nitrate group decomposition begins before dehydration is complete. The authors utilized DTA, XPA, and IR analysis to study the physicochemical properties of the immobilizer produced by a single impregnation of the foamed corundum with rare earth (La, Eu, Dy, Tb, and Yb) nitrate solutions and subsequent firing at 900 degrees C for 30 min. The choice of these rare earths was dictated by the fact that the Ln 2 O 3 -AlO 3 system can be divided into three groups on the basis of phase ratios: La-Nd, Sm-Eu, and Gd-Lu. Lanthanide monoaluminates are formed in all these groups, and the difference lies in the other reaction products generated: LnAl 11 O 18 for La-Nd, LnAl 11 O 18 and Ln 4 Al 2 O 9 for Sm-Eu, and Ln 4 Al 2 O 9 and Ln 3 Al 5 O 12 for Gd-Lu

Mechanoluminescence of Dy doped strontium aluminate nanophosphors

Energy Technology Data Exchange (ETDEWEB)

Sharma, Ravi, E-mail: rvsharma65@gmail.com [Department of Physics, Govt. Arts and Commerce Girls College, Raipur, C.G. 492001 (India); Bisen, D.P. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Chandra, B.P. [Department of Postgraduate Studies and Research in Physics and Electronics, Rani Durgavati University, Jabalpur 482001 (India)

2015-12-15

Nanosized strontium aluminate phosphors activated with Dy{sup 3+} were prepared by a combustion method. Nanophosphor was prepared by this method at reaction temperatures as low as 600 °C. Powder X-ray diffraction (XRD), scanning electron microscope analysis was used to characterize the prepared product. The monoclinic phase was observed in the XRD pattern. The particle size of the samples was calculated around 35 nm. The SEM images show irregular shape of the prepared nanophosphor. Two peaks were found in the mechanoluminescence (ML) response curve plotted between time and ML intensity. The H{sub 3}BO{sub 3} added strontium aluminate phosphors activated with Dy show more bright ML peak as compared to the powders of SrAl{sub 2}O{sub 4}:Dy{sup 3+} without H{sub 3}BO{sub 3.} It was found that the PL and ML intensity increases with increasing concentration of Dy, it becomes maximum for 3% of Dy. The photoluminescence emission shows two intense fluorescence transitions peaks at 498 nm and 583 nm, {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} in the blue and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} in the yellow-orange wavelength region. - Highlights: • Combustion synthesis route is used to prepare the SrAl{sub 2}O{sub 4}: Dy {sup 3+} nanophosphors. • The size of the synthesized sample was found to be in the nano-meter range. • The mechanoluminescence of SrAl{sub 2}O{sub 4}:Dy {sup 3+} nanophosphors is studied. • The photoluminescence of SrAl{sub 2}O{sub 4}: Dy {sup 3+} nanophosphors showed blue-shift as compared to bulk. • Effect of H{sub 3}BO{sub 3} on the mechanoluminescence of SrAl{sub 2}O{sub 4}:Dy{sup 3+} was studied.

Cytotoxic and genotoxic effect of the [166Dy]Dy/166Ho-EDTMP in vivo generator system in mice

International Nuclear Information System (INIS)

Pedraza-Lopez, Martha; Ferro-Flores, Guillermina; Arteaga de Murphy, Consuelo; Morales-Ramirez, Pedro; Piedras-Ross, Josefa; Murphy-Stack, Eduardo; Hernandez-Oviedo, Omar

2004-01-01

Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. [ 166 Dy]Dy/ 166 Ho-ethylenediaminetetramethylene phosphonate (EDTMP) forms a stable in vivo generator system with selective skeletal uptake in mice; therefore, it could work as a potential and improved agent for marrow ablation. Induced bone marrow cytotoxicity and genotoxicity are determined by the reduction of reticulocytes (RET) and elevation of micronucleated reticulocyte (MN-RET) in peripheral blood and ablation by bone marrow histological studies. The aim of this study was to determine the bone marrow cytotoxic and genotoxic effect of the [ 166 Dy]Dy/ 166 Ho-EDTMP in vivo generator system in mice and to evaluate by histopathology its myeloablative potential. Enriched 166 Dy 2 O 3 was irradiated and [ 166 Dy]DyCl 3 was added to EDTMP in phosphate buffer (pH 8.0) in a molar ratio of 1:1.75. QC was determined by TLC. Dy-EDTMP complex was prepared the same way with nonirradiated dysprosium oxide. A group of BALB/c mice were intraperitoneally injected with the radiopharmaceutical and two groups of control animals were injected with the cold complex and with 0.9% sodium chloride, respectively. A blood sample was taken at the beginning of the experiments and every 48 h for 12 days postinjection. The animals were sacrificed, organs of interest taken out and the radioactivity determined. The femur was used for histological studies. Flow cytometry analysis was used to quantify the frequency of RET and MN-RET in the blood samples. The MCNP4B Monte Carlo computer code was used for dosimetry calculations. Radiochemical purity was 99% and the mean specific activity was 1.3 MBq/mg. The RET and MN-RET frequency were statistically different in the treatment at the end of the 12-day period demonstrating cytotoxicity and genotoxicity induced by the in vivo generator system. The histology studies show that there was

Asteroids Dynamic Site-AstDyS

Science.gov (United States)

Knezevic, Zoran; Milani, Andrea

2012-08-01

The AstDyS online information service (http://hamilton.dm.unipi.it/astdys/) contains data on numbered and multi - opposition asteroids, including orbital elements, their uncertainty, proper elements, ephemerides with uncertainty, and more. AstDyS also provides additional scientific output computed from the raw observational data. This value added currently includes: more accurate orbits computed with advanced dynamical and observational error model s; their uncertainty, as expressed by the covariance matrix formalism; ephemerides computed on request for each observer, with uncertainty; mean and proper orbital elements (for this output, AstDyS is the primary source worldwide); statistical quality control, providing a rigorous observational error model. All this is available with a sophisticated web interface, providing multiple search functions and online computations as well as complete orbital and residual files. There are several ways in which the A stDyS service could be expanded and improved in the next future, like the explicit classification of asteroids into asteroid families, the classification of resonant asteroids, and an updated self - consistent population model (to be used, e.g., for survey simulations). The IAU Division I endorsed the proposal for AstDyS to become an IAU (permanent) service, which would include the IAU supervision of the AstDyS system, keeping under control the quality of the work and the continuous update under conditions of scientific competition.

The Ras antagonist, farnesylthiosalicylic acid (FTS, decreases fibrosis and improves muscle strength in dy/dy mouse model of muscular dystrophy.

Directory of Open Access Journals (Sweden)

Yoram Nevo

Full Text Available The Ras superfamily of guanosine-triphosphate (GTP-binding proteins regulates a diverse spectrum of intracellular processes involved in inflammation and fibrosis. Farnesythiosalicylic acid (FTS is a unique and potent Ras inhibitor which decreased inflammation and fibrosis in experimentally induced liver cirrhosis and ameliorated inflammatory processes in systemic lupus erythematosus, neuritis and nephritis animal models. FTS effect on Ras expression and activity, muscle strength and fibrosis was evaluated in the dy(2J/dy(2J mouse model of merosin deficient congenital muscular dystrophy. The dy(2J/dy(2J mice had significantly increased RAS expression and activity compared with the wild type mice. FTS treatment significantly decreased RAS expression and activity. In addition, phosphorylation of ERK, a Ras downstream protein, was significantly decreased following FTS treatment in the dy(2J/dy(2J mice. Clinically, FTS treated mice showed significant improvement in hind limb muscle strength measured by electronic grip strength meter. Significant reduction of fibrosis was demonstrated in the treated group by quantitative Sirius Red staining and lower muscle collagen content. FTS effect was associated with significantly inhibition of both MMP-2 and MMP-9 activities. We conclude that active RAS inhibition by FTS was associated with attenuated fibrosis and improved muscle strength in the dy(2J/dy(2J mouse model of congenital muscular dystrophy.

Nuclear Data Sheets for A = 139

Energy Technology Data Exchange (ETDEWEB)

Joshi, Paresh K.; Singh, Balraj; Singh, Sukhjeet; Jain, Ashok K.

2016-12-15

The experimental nuclear spectroscopic data for known nuclides of mass number 139 (Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy) have been evaluated and presented together with adopted properties for levels and gamma rays. This evaluation represents a revision of previous one (2001Bu16) by T.W. Burrows. Since then extensive new data have become available for many A=139 nuclides although, no excited state data are yet available for {sup 139}Sn, {sup 139}Sb, {sup 139}Tb, and {sup 139}Dy. The decay schemes of {sup 139}Sn, {sup 139}Sb, {sup 139}I, {sup 139}Tb and {sup 139}Dy nuclei are not known, and those for {sup 139}Gd and {sup 139}Eu are poorly known. Particle-transfer data are available for {sup 139}Ba, {sup 139}La, {sup 139}Ce and {sup 139}Pr. Limited high-spin data are available for {sup 139}Te, {sup 139}I, {sup 139}Cs, {sup 139}Ba, {sup 139}La and {sup 139}Ce, while such data are extensive for {sup 139}Pr, {sup 139}Nd, {sup 139}Pm, {sup 139}Sm, {sup 139}Eu and {sup 139}Gd. Recent {sup 139}Pm high-spin data from two independent studies using the same reaction and similar beam energy are in conflict and could be improved using state-of-the-art large gamma-detector arrays in contrast to the smaller arrays currently used. Cases for which no new experimental information are available since the last update have undergone checking resulting in some changes in the current work, but for the most part these are taken from the previous evaluations. Thus, the present work has greatly benefited from all prior NDS evaluations (2001Bu16, 1989Bu12, 1981Pe04, 1974Gr46), but at the same time data presented herein supersede those in the earlier evaluations.

Luminescence properties of phosphate phosphor Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Yang, Fu [College of Science, Hebei North University, Zhangjiakou 075000 (China); Liu, Yufeng, E-mail: liuyufeng4@126.com [State Key Lab of Power Systems, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Tian, Xiaodong; Dong, Guoyi [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Yu, Quanmao [Institute of Functional Materials, Jiangxi University of Finance & Economics, Nanchang 330013 (China)

2015-05-15

A series of reddish orange-emitting phosphate phosphors Ba{sub 3}Y{sub 1−x}(PO{sub 4}){sub 3}:xSm{sup 3+}(0.01≤x≤0.20) were synthesized by solid-state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of as-synthesized phosphors. The optimized phosphors Ba{sub 3}Y{sub 0.95}(PO{sub 4}){sub 3}:0.05Sm{sup 3+} present several excitation bands from 300 to 500 nm, and exhibit intense reddish orange-emitting properties. The energy transfer type between Sm{sup 3+} ions was confirmed as d–d interaction by using Van Uitert model. The chromatic properties of the typical sample Ba{sub 3}Y(PO{sub 4}){sub 3}:0.05Sm{sup 3+} phosphor have been found to have chromaticity coordinates of (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. These results indicated that Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} phosphors have potential applications in the field of lighting and display due to their effective excitation in the near-ultraviolet range. - Graphical abstract: The color coordinates for 5 mol% Sm{sup 3+} doped Ba{sub 3}Y(PO{sub 4}){sub 3} phosphor were calculated to be (0.583, 0.405), which are located in reddish orange region under the excitation of 401 nm. The peaks of Ba{sub 3}Y{sub 0.95}(PO{sub 4}){sub 3}:0.05Sm{sup 3+} phosphor with the highest emission intensity at 600 nm are broader than those of Y{sub 2}O{sub 3}:Eu{sup 3+} and Y{sub 2}O{sub 2}S:Eu{sup 3+} phosphors. All these characteristics suggest that Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} phosphors are suitable for near-UV (370–410 nm) excitation and can be applicable to near UV-based WLEDs. ▪ - Highlights: • Different concentration Sm{sup 3+}-doped Ba{sub 3}Y(PO{sub 4}){sub 3} phosphors were fabricated by solid state method. • The optimized phosphors present the several excitation bands from 300 to 500 nm. • The Ba{sub 3}Y(PO{sub 4}){sub 3}:Sm{sup 3+} shows bright reddish orange

Yb3+ can be much better than Dy3+: SMM properties and controllable self-assembly of novel lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes.

Science.gov (United States)

Gavrikov, Andrey V; Efimov, Nikolay N; Ilyukhin, Andrey B; Dobrokhotova, Zhanna V; Novotortsev, Vladimir M

2018-05-01

The first representatives of the binuclear lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes, namely isostructural compounds [Ln(dnbz)(acac)2(H2O)(EtOH)]2 (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), and Yb (8); dnbz - 3,5-dinitrobenzoate anion; acac - acetylacetonate (pentane-2,4-dionate) anion) were prepared and characterized. The SMM behavior of the Yb compound 8 was shown to be surprisingly less sensitive to the composition of the Yb3+ coordination environment in comparison with that of the Dy derivative. For Yb compound 8, the anisotropy barrier is Δeff/kB = 26 K under the dc field of 2000 Oe. This value is the highest one currently known for binuclear Yb complexes.

Rare earth niobate coordination polymers

Science.gov (United States)

Muniz, Collin N.; Patel, Hiral; Fast, Dylan B.; Rohwer, Lauren E. S.; Reinheimer, Eric W.; Dolgos, Michelle; Graham, Matt W.; Nyman, May

2018-03-01

Rare-earth (RE) coordination polymers are infinitely tailorable to yield luminescent materials for various applications. Here we described the synthesis of a heterometallic rare-earth coordination compound ((CH3)2SO)3(RE)NbO(C2O4)3((CH3)2SO) = dimethylsulfoxide, DMSO, (C2O2= oxalate), (RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb). The structure was obtained from single crystal X-ray diffraction of the La analogue. The Nb˭O and DMSO terminal-bonding character guides assembly of an open framework structure with noncentrosymmetric RE-coordination geometry, and large spacing between the RE centers. A second structure was observed by PXRD for the smaller rare earths (Dy, Ho, Er, Yb); this structure has not yet been determined. The materials were further characterized using FTIR, and photoluminescence measurements. Characteristic excitation and emission transitions were observed for RE = Nd, Sm, Eu, and Tb. Quantum yield (QY) measurements were performed by exciting Eu and Tb analoges at 394 nm (QY 66%) and 464 nm (QY 71%) for Eu; and 370 nm (QY=40%) for Tb. We attribute the high QY and bright luminescence to two main structure-function properties of the system; namely the absence of water in the structure, and absence of concentration quenching.

Ultraviolet dosimetry using thermoluminescent phosphors - an update

International Nuclear Information System (INIS)

Nagpal, J.S.

1998-04-01

Intrinsic response of various thermoluminescent (TL) materials such as CaSO 4 (Dy, Eu, Mn, Sm, Tb, or Tm), LiF (Mg, Cu, P), Mg 2 SiO 4 :Tb, CaF 2 :Dy, CaF 2 :Tb, ThO 2 :Tb and Al 2 O 3 (Si, Ti); cathodoluminescent phosphors Y 3 Al 5 O 12 :Ce, Y 3 Al 5 O 12 :Tb and Y(V,P)O 4 :Eu; and fluorescent lamp phosphors calcium halophosphate (Mn,Sb) and Ce Mg aluminate (Eu, Tb) to ultraviolet (UV) radiations has been studied. Intrinsic TL response of most of the phosphors is rate (radiant flux) dependent. For the first time, UV response of the materials is reported for a fixed total radiant energy (total UV dose), at a single radiant flux (260 μW.cm -2 ), for an appropriate comparison. A wide range of UV sensitivity is observed. Studies conducted using UV radiation from two unfiltered low pressure mercury lamps show significant differences in glow curves, as compared to those obtained with nearly monochromatic UV radiations. Photons of wavelength 365 nm induce bleaching of TL induced by 254 nm photons, in most of the materials. Sequential/tandem exposures to 254 nm and 365 nm photons have yielded new but alarming results in CaF 2 :Tb. Preferential induction and bleaching of specific TL glow peaks by 365 nm and 254 nm photons are interesting characteristics discovered in CaSO 4 :Eu. Photoluminescence studies of Tb 3+ and Eu 3+ activated phosphors have augmented the inferences drawn from the bleaching effects produced by 365 nm photons. Earlier work carried out on phototransferred thermoluminescence of CaSO 4 :Dy-teflon dosimeters, TLD-100, Mg 2 SiO 4 :Tb and Al 2 O 3 (Si,Ti) has also been reviewed. (author)

A new TRISTAN thermal ion source

International Nuclear Information System (INIS)

Piotrowski, A.; Gill, R.L.; McDonald, D.C.

1984-01-01

A new thermal ion source with an integrated target which is heated by electron bombardment to a temperature of 2500 0 C has been developed for the TRISTAN on-line fission product mass separator at Brookhaven National Laboratory. Initial on-line tests demonstrated that this ion source can extend the range of accessible elements to the rare-earth region. Yields are presented for isotopes of Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Ga, Ge, As, Y, Zr, Nb, In, Sn and Sb. (orig.)

Gibbs free energy of formation of liquid lanthanide-bismuth alloys

International Nuclear Information System (INIS)

Sheng Jiawei; Yamana, Hajimu; Moriyama, Hirotake

2001-01-01

The linear free energy relationship developed by Sverjensky and Molling provides a way to predict Gibbs free energies of liquid Ln-Bi alloys formation from the known thermodynamic properties of aqueous trivalent lanthanides (Ln 3(5(6+ ). The Ln-Bi alloys are divided into two isostructural families named as the LnBi 2 (Ln=La, Ce, Pr, Nd and Pm) and LnBi (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb). The calculated Gibbs free energy values are well agreed with experimental data

Genotoxic and cytotoxic damage by the therapeutic radiopharmaceutical [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP as in vivo generator system; Dano genotoxico y citotoxico por el radiofarmaco terpeutico [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP como sistema de generador in vivo

Energy Technology Data Exchange (ETDEWEB)

Pedraza L, M; Piedras R, J [Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran. Vasco. de Quiroga 15, 14000 Mexico D.F. (Mexico); Ferro F, G; Morales R, P [ININ, Km. 36.5 Carretera Mexico-Toluca, Ocoyoacac, 52045 Estado de Mexico (Mexico); Murphy S, E [Hospital Santaelena, Mexico D.F. (Mexico); Hernandez O, O [Escuela Superior de Fisica y Matematicas, IPN, Mexico D.F. (Mexico)

2005-07-01

In patients with leukemias and multiple myeloma, the cure can be obtained to inclination of a bone marrow transplant (m.o.), for that which one is used a combination of external radiotherapy and chemotherapy with the consequent toxicity to healthy organs. The complex [{sup 166}Dy]Dy/{sup 166}Ho-ethylenediaminetetramethylenephosphonate ([{sup 166}Dy]Dy/{sup 166}Ho-EDTMP) it forms a generator system in vivo stable with bony selective likeness in mice therefore, this it could work as a therapeutic radiopharmaceutical for bone marrow ablation. The objective of this original work was to determine the genotoxic and cytotoxic damage produced by the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP like a generator system in vivo by means of the reticulocytes reduction (RET) and micronucleus elevation in reticulocytes (RET-MN) in peripheral blood and to evaluate its myeloablative potential for histopathologic studies. It was irradiated {sup 166}Dy{sub 2}O{sub 3} enriched and it was add in form {sup 166}DyCI{sub 3} to the EDTMP in a softening media of phosphates (pH 8), the optimal molar relationship {sup 166}Dy: EDTMP was 1.7:1 and the radiochemical purity was evaluated by ITLC. The Dy:EDTMP complexes, non radioactive, its were prepared in the same way with non irradiated dysprosium oxide. A group of BALB/c mice was injected intraperitoneally with the radiopharmaceutical and two groups of control mice were injected with the non radioactive complex and with sodium chloride 0.9% respectively. Before injecting each one of the solutions it was take a basal sample of peripheral blood of the mouse tail and each 48 h post-injection during 12 d. The animals were sacrificed to obtain the organs of interest and to determine the radioactivity in each one. The femur was used for the histopathologic studies. The quantification of the frequency of RET and RET-MN was carried out by flow cytometry of the sanguine samples and the Monte Carlo code MCNP4B for the dosimetry calculations was used. The

Radiation damage in SmS, SmSsub(1-x)Psub(x) and SmB6

International Nuclear Information System (INIS)

Morillo, J.; Bordier, G.; de Novion, C.H.; Senateur, J.P.; Jun, J.

1984-08-01

Large conductivity increases under 21 K electron or neutron irradiations are observed in SmS and SmSsub(1-x)Psub(x). It is shown that they are related to Sm defects. A possible mechanism is 4f electron delocalization around radiation defects. In SmB 6 , the low temperature resistivity increase desappears under 21 K irradiation. The thermal stability of the defects is also investigated up to room temperature

Magnetic properties of the ternary carbide DyCoC2 studied by magnetization measurements, neutron diffraction and 161Dy Moessbauer spectroscopy

International Nuclear Information System (INIS)

Amanai, H.; Onodera, H.; Ohashi, M.; Matsuo, S.; Yamauchi, H.

1995-01-01

The magnetic properties of DyCoC 2 have been investigated by means of magnetization measurements, powder neutron diffraction and 161 Dy Moessbauer spectroscopy. The magnetization versus temperature curves of a single-crystalline sample reveal that the magnetic structure of DyCoC 2 is a simple collinear ferromagnetic one below T C =10.0 K. At 4.2 K, the magnitude of the Dy moment is 8.7(1)μ B , whose direction is defined by an angle of 38.0(5) from the a-axis toward the c-axis. The magnetic structure and the magnitude of the moment are also confirmed by the results of powder neutron diffraction experiments and 161 Dy Moessbauer spectroscopy, respectively. ((orig.))

Possibilities for standardization of {sup 152}Eu by liquid scintillation and gamma spectrometry; Possibilidades para padronização do {sup 152}Eu por cintilação líquida e por espectrometria gama

Energy Technology Data Exchange (ETDEWEB)

Ferreira Filho, A.L.; Cruz, P.A.L. da; Silva, R.L. da; Delgado, J.U., E-mail: alfredo@ird.gov.br [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiações Ionizantes; Lopes, R.T. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (LIN/PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear

2017-07-01

The {sup 152}Eu has a half-life of 13.5 years and a very complex decay scheme with two branches of decay. It disintegrates in {sup 152}Sm by electronic capture (72.1%) or by emission of positrons (0.027%) and in {sup 152}Gd by beta emission minus (27.9%). The child nucleus, {sup 152}Sm, has 19 excited levels, while {sup 152}Gd has 15. The direct decay of the parent nucleus to the fundamental state of the child nucleus does not exist. The decay of a {sup 152}Eu source results in emissions of 4 KX photons and 132 gamma rays, which is the reason for a lot of true coincidence-sum. The particular interest in this radionuclide is explained by its wide use in the calibration in energy and efficiency of gamma spectrometers with semiconductor detectors, since the range of energy of the emitted photons, varying from 40 to 1769 keV. But, because of such a complex decay scheme, the determination of {sup 152}Eu activity presents many difficulties. The CIEMAT / NIST liquid scintillation counting method and the peak-sum coincidence method, an absolute measurement technique using coincidence counts and photon spectrometry, have been tested in the LNMRI-IRD to standardize {sup 152}Eu solutions.

Genotoxic and cytotoxic damage by the therapeutic radiopharmaceutical [166Dy]Dy/166Ho-EDTMP as in vivo generator system

International Nuclear Information System (INIS)

Pedraza L, M.; Piedras R, J.; Ferro F, G.; Morales R, P.; Murphy S, E.; Hernandez O, O.

2005-01-01

In patients with leukemias and multiple myeloma, the cure can be obtained to inclination of a bone marrow transplant (m.o.), for that which one is used a combination of external radiotherapy and chemotherapy with the consequent toxicity to healthy organs. The complex [ 166 Dy]Dy/ 166 Ho-ethylenediaminetetramethylenephosphonate ([ 166 Dy]Dy/ 166 Ho-EDTMP) it forms a generator system in vivo stable with bony selective likeness in mice therefore, this it could work as a therapeutic radiopharmaceutical for bone marrow ablation. The objective of this original work was to determine the genotoxic and cytotoxic damage produced by the [ 166 Dy]Dy/ 166 Ho-EDTMP like a generator system in vivo by means of the reticulocytes reduction (RET) and micronucleus elevation in reticulocytes (RET-MN) in peripheral blood and to evaluate its myeloablative potential for histopathologic studies. It was irradiated 166 Dy 2 O 3 enriched and it was add in form 166 DyCI 3 to the EDTMP in a softening media of phosphates (pH 8), the optimal molar relationship 166 Dy: EDTMP was 1.7:1 and the radiochemical purity was evaluated by ITLC. The Dy:EDTMP complexes, non radioactive, its were prepared in the same way with non irradiated dysprosium oxide. A group of BALB/c mice was injected intraperitoneally with the radiopharmaceutical and two groups of control mice were injected with the non radioactive complex and with sodium chloride 0.9% respectively. Before injecting each one of the solutions it was take a basal sample of peripheral blood of the mouse tail and each 48 h post-injection during 12 d. The animals were sacrificed to obtain the organs of interest and to determine the radioactivity in each one. The femur was used for the histopathologic studies. The quantification of the frequency of RET and RET-MN was carried out by flow cytometry of the sanguine samples and the Monte Carlo code MCNP4B for the dosimetry calculations was used. The radiochemical purity was 99% and in average the specific

Synthesis and magnetic properties of CoFe2O4 spinel ferrite nanoparticles doped with lanthanide ions

International Nuclear Information System (INIS)

Kahn, Myrtil L.; Zhang, Z. John

2001-01-01

Lanthanide ions have been doped into cobalt spinel ferrites using an oil-in-water micellar method to form CoLn 0.12 Fe 1.88 O 4 nanoparticles with Ln=Ce, Sm, Eu, Gd, Dy, or Er. Doping with lanthanide ions (Ln III ) modulates the magnetic properties of cobalt spinel ferrite nanoparticles. In particular cases of Gd 3+ or Dy 3+ ions, a dramatic increase in the blocking temperature and coercivity is observed. Indeed, the introduction of only 4% of Gd 3+ ions increases the blocking temperature ∼100 K and the coercivity 60%. Initial studies on the magnetic properties of these doped nanoparticles clearly demonstrate that the relationship between the modulation of magnetic properties and the nature of doped Ln III ions is interesting but very complex. [copyright] 2001 American Institute of Physics

Evaluation of Ablation rate by the change of Sacrificial Material for PECS in EU-APR

International Nuclear Information System (INIS)

Hwang, Do Hyun; Kim, Yong Soo; Lee, Keun Sung

2015-01-01

EU-APR, modified and improved from its original design of APR1400, has been developed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. In EU-APR, Severe Accident Mitigation Systems are dedicated to providing an independent defense line from that of Engineered Safety Feature (ESF) and Diverse Safety Feature (DSF). They consist of Emergency Reactor Depressurization System (ERDS), Passive Ex-vessel corium retaining and Cooling System (PECS), Severe Accident Containment Spray System (SACSS), Hydrogen Mitigation System (HMS) and Containment Filtered Vent System (CFVS). The PECS, so called core catcher, was introduced to prevent the Molten Core Concrete Interaction (MCCI) after Reactor Vessel (RV) failure. The PECS has experienced a lot of changes from its original design. Recently, the most significant change was that as a SM, limestone concrete is installed on PECS's body wall instead of previous sacrificial material rich in Fe 2 O 3 . The main reason of this design change is to overcome the issue that the sacrificial material is ablated rather too fast when reacting with corium that contains a large fraction of Zr metal. Other changes in the geometry of PECS's wall and downcomer design are considered as minor ones. In this paper, the comparison of ablation rates between previous SM and limestone concrete is carried out using MAAP5 code with respective MCCI model according to the material. In this paper, major improvements of MAAP5 model for PECS in EU-APR are presented and the evaluation of ablation rate for the previous SM model and the new LC model is carried out by means of ablation depths with LBLOCA sequence. Two models have respective unique ablation process. The ablation of LC model proceeds at a constant rate regardless of water while the ablation of SM model proceeds at a faster rate before the arrival of cooling water for corium and SM mixture. The change of sacrificial material also

Fabrication and photoluminescence properties of color-tunable light emitting lanthanide doped GdVO{sub 4} hierarchitectures

Energy Technology Data Exchange (ETDEWEB)

Amurisana, Bao, E-mail: amurisana@163.com [Institute of Chemical Biology, Hohhot Vocational College, Hohhot 010051 (China); Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China); Bao, Lihong [Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China); Bao, Liang [Institute of Chemical Biology, Hohhot Vocational College, Hohhot 010051 (China); Tegus, O., E-mail: tegusph@imnu.edu.cn [Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China)

2017-04-15

The flower-like GdVO{sub 4}:Ln{sup 3+}( Ln{sup 3+}=Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+}, Tm{sup 3+}) hierarchitectures have been successfully synthesized on a glass slide substrate through a one-pot hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na{sub 2}H{sub 2}L, where L{sup 4-}=(CH{sub 2}COO){sub 2}N(CH{sub 2}){sub 2}N(CH{sub 2}COO){sub 2}{sup 4-}). A high density and ordered flower-like GdVO{sub 4}:Ln{sup 3+} hierarchitectures grew epitaxially on glass substrate. The as-prepared flower-like architectures with the size about 6 μm are constructed by the numerous radially oriented single-crystalline nanorods with the width from 20 nm to 200 nm and the length from 500 nm to 3 μm. The morphologies, the thickness, and the density of as-grown flower clusters can be readily tuned by tailoring the growth time and Na{sub 2}H{sub 2}L/Gd{sup 3+} molar ratio. The possible formation mechanism of flower-like GdVO{sub 4}:Ln{sup 3+} hierarchitectures is discussed on the basis of the results from the controlled experiments under hydrothermal conditions. Because of an energy transfer from vanadate groups to dopants, the flower-like GdVO{sub 4}:Ln{sup 3+}( Ln{sup 3+}=Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+} and Tm{sup 3+}) superstructures showed strong characteristic dominant emissions of the Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+} and Tm{sup 3+} ions at 617 nm ({sup 5}D{sub 0}→{sup 7}F{sub 2}, strong red), 575 nm ({sup 4}F{sub 9/2}→{sup 6}H{sub 13/2}, yellow), 604 nm ({sup 4}G{sub 5/2}→{sup 6}H{sub 7/2}, orange-red) and 476 nm ({sup 1}G{sub 4}–{sup 3}H{sub 6}, blue) under ultraviolet excitation, respectively.Further, the emission color of the product can also be tuned by selecting the dopant Ln{sup 3+} with characteristic emissions and varying the concentration ratio of co-doping activators. This approach could be extended to the fabrication of hierarchical structures for other oxide micro/nanomaterials, and may provide a general way to achieve multicolor

Faraday effect in γ-Dy2S3 and c-Dy2O3 paramagnetic crystals

International Nuclear Information System (INIS)

Shelykh, A.I.

1987-01-01

Studies of spectral and temperature dependences of Faraday effect in γ-Dy 2 S 3 and C-Dy 2 O 3 paramagnetic crystals are conducted. Paramagnetism of these crystals is brought about by Dy 3+ ions. Estimation of the effect of such factors as the value of paramagnetic ion concentration, width of the forbidden band, crystallochemical composition on magnetooptical effect in the considered compounds of dysprosium is carried out on the basis of the obtained experimental data and theoretical analysis. It is shown, that the Faraday effect in the considered compounds of dysprosium as well as the value of paramagnetic moment may be regarded rather accurately in free ion approximation

Room-temperature ferromagnetism in Dy films doped with Ni

International Nuclear Information System (INIS)

Edelman, I.; Ovchinnikov, S.; Markov, V.; Kosyrev, N.; Seredkin, V.; Khudjakov, A.; Bondarenko, G.; Kesler, V.

2008-01-01

Temperature, magnetic field and spectral dependences of magneto-optical effects (MOEs) in bi-layer films Dy (1-x) Ni x -Ni and Dy (1-x) (NiFe) x -NiFe were investigated, x changes from 0 to 0.06. Peculiar behavior of the MOEs was revealed at temperatures essentially exceeding the Curie temperature of bulk Dy which is explained by the magnetic ordering of the Dy layer containing Ni under the action of two factors: Ni impurities distributed homogeneously over the whole Dy layer and atomic contact of this layer with continues Ni layer. The mechanism of the magnetic ordering is suggested to be associated with the change of the density of states of the alloy Dy (1-x) Ni x owing to hybridization with narrow peaks near the Fermi level character for Ni

DySectAPI: Scalable Prescriptive Debugging

DEFF Research Database (Denmark)

Jensen, Nicklas Bo; Karlsson, Sven; Quarfot Nielsen, Niklas

We present the DySectAPI, a tool that allow users to construct probe trees for automatic, event-driven debugging at scale. The traditional, interactive debugging model, whereby users manually step through and inspect their application, does not scale well even for current supercomputers. While...... lightweight debugging models scale well, they can currently only debug a subset of bug classes. DySectAPI fills the gap between these two approaches with a novel user-guided approach. Using both experimental results and analytical modeling we show how DySectAPI scales and can run with a low overhead...

Effect of Ligand Substitution around the Dy(III) on the SMM Properties of Dual-Luminescent Zn-Dy and Zn-Dy-Zn Complexes with Large Anisotropy Energy Barriers: A Combined Theoretical and Experimental Magnetostructural Study.

Science.gov (United States)

Costes, Jean Pierre; Titos-Padilla, Silvia; Oyarzabal, Itziar; Gupta, Tulika; Duhayon, Carine; Rajaraman, Gopalan; Colacio, Enrique

2016-05-02

The new dinuclear Zn(II)-Dy(III) and trinuclear Zn(II)-Dy(III)-Zn(II) complexes of formula [(LZnBrDy(ovan) (NO3)(H2O)](H2O)·0.5(MeOH) (1) and [(L(1)ZnBr)2Dy(MeOH)2](ClO4) (3) (L and L(1) are the dideprotonated forms of the N,N'-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato and 2-{(E)-[(3-{[(2E,3E)-3-(hydroxyimino)butan-2-ylidene ]amino}-2,2-dimethylpropyl)imino]methyl}-6-methoxyphenol Schiff base compartmental ligands, respectively) have been prepared and magnetostructurally characterized. The X-ray structure of 1 indicates that the Dy(III) ion exhibits a DyO9 coordination sphere, which is made from four O atoms coming from the compartmental ligand (two methoxy terminal groups and two phenoxido bridging groups connecting Zn(II) and Dy(III) ions), other four atoms belonging to the chelating nitrato and ovanillin ligands, and the last one coming to the coordinated water molecule. The structure of 3 shows the central Dy(III) ion surrounded by two L(1)Zn units, so that the Dy(III) and Zn(II) ions are linked by phenoxido/oximato bridging groups. The Dy ion is eight-coordinated by the six O atoms afforded by two L(1) ligands and two O atoms coming from two methanol molecules. Alternating current (AC) dynamic magnetic measurements of 1, 3, and the previously reported dinuclear [LZnClDy(thd)2] (2) complex (where thd = 2,2,6,6-tetramethyl-3,5-heptanedionato ligand) indicate single molecule magnet (SMM) behavior for all these complexes with large thermal energy barriers for the reversal of the magnetization and butterfly-shaped hysteresis loops at 2 K. Ab initio calculations on 1-3 show a pure Ising ground state for all of them, which induces almost completely suppressed quantum tunnelling magnetization (QTM), and thermally assisted quantum tunnelling magnetization (TA-QTM) relaxations via the first excited Kramers doublet, leading to large energy barriers, thus supporting the observation of SMM behavior. The comparison between the experimental and theoretical

Lanthanide phosphonates: Synthesis, thermal stability and magnetic characterization

Energy Technology Data Exchange (ETDEWEB)

Amghouz, Z., E-mail: amghouz.uo@uniovi.es [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Garcia, J.R.; Garcia-Granda, S. [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Clearfield, A. [Department of Chemistry, Texas A and M University, College Station, TX 77842-3012 (United States); Rodriguez Fernandez, J.; Pedro, I. de [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

2012-09-25

Highlights: Black-Right-Pointing-Pointer Report of the complete series of lanthanide 1,4-phenylbis(phosphonate). Black-Right-Pointing-Pointer Synthesis under conventional hydrothermal synthesis or microwave-assisted hydrothermal synthesis. Black-Right-Pointing-Pointer Cation size is the key factor for the structural and particles size variations. Black-Right-Pointing-Pointer Thermal behaviour is characterized by unusual very high thermal stability. - Abstract: Series of novel organic-inorganic hybrids materials based on trivalent lanthanides (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and 1,4-phenylbis(phosphonate) obtained under hydrothermal conditions either by oven heat or microwave irradiation. The anhydrous compounds containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho, are isostructural. However, the compounds based on Y, Er, Tm, Yb, and Lu are hydrated and their structures have not yet been solved. The series of compounds are characterized by PXRD, TEM, SEM-EDX and thermal analyses (TG-MS and DSC). TEM study show a variable particles size with a minimum mean-particle size of ca. 30 nm. These compounds exhibit unusual very high thermal stability. The size of particles and the thermal stability are depending on lanthanide(III) cation features. All the investigated materials show paramagnetic behaviour. The magnetic susceptibility data follow a Curie-Weiss laws with paramagnetic effective moments in good agreement with those expected for Ln{sup 3+} free ions.

A family of acetato-diphenoxo triply bridged dimetallic Zn(II)Ln(III) complexes: SMM behavior and luminescent properties.

Science.gov (United States)

Oyarzabal, Itziar; Artetxe, Beñat; Rodríguez-Diéguez, Antonio; García, JoséÁngel; Seco, José Manuel; Colacio, Enrique

2016-06-21

Eleven dimetallic Zn(II)-Ln(III) complexes of the general formula [Zn(µ-L)(µ-OAc)Ln(NO3)2]·CH3CN (Ln(III) = Pr (1), Nd (2), Sm (3), Eu (4), Gd (5), Tb (6), Dy (7), Ho (8), Er (9), Tm (10), Yb (11)) have been prepared in a one-pot reaction from the compartmental ligand N,N'-dimethyl-N,N'-bis(2-hydroxy-3-formyl-5-bromo-benzyl)ethylenediamine (H2L). In all these complexes, the Zn(II) ions occupy the internal N2O2 site whereas the Ln(III) ions show preference for the O4 external site. Both metallic ions are bridged by an acetate bridge, giving rise to triple mixed diphenoxido/acetate bridged Zn(II)Ln(III) compounds. The Nd, Dy, Er and Yb complexes exhibit field induced single-ion magnet (SIM) behaviour, with Ueff values ranging from 14.12 to 41.55 K. The Er complex shows two relaxation processes, but only the second relaxation process with an energy barrier of 21.0 K has been characterized. The chromophoric L(2-) ligand is able to act as an "antenna" group, sensitizing the near-infrared (NIR) Nd(III) and Yb(III)-based luminescence in complexes 2 and 11 and therefore, both compounds can be considered as magneto-luminescent materials. In addition, the Sm(III), Eu(III) and Tb(III) derivatives exhibit characteristic emissions in the visible region.

Synthesis, structure and magnetic properties of DyAl2 nanoparticles

International Nuclear Information System (INIS)

Zhang, W.S.; Brueck, E.; Zhang, Z.D.; Tegus, O.; Li, W.F.; Si, P.Z.; Geng, D.Y.; Klaasse, J.C.P.; Buschow, K.H.J.

2006-01-01

DyAl 2 nanoparticles have been prepared by means of arc discharge in a mixture of argon and hydrogen gas. The structure of DyAl 2 nanoparticles is studied by means of X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. X-ray photoelectron spectroscopy shows that the as-prepared DyAl 2 nanoparticles are coated with a layer of Al 2 O 3 phase on the surface, and their sizes vary from 20 nm to about 100 nm. The DyAl 2 nanoparticles exhibit ferromagnetic properties that are different from bulk DyAl 2 compound. The gradual decrease of the magnetization with increasing temperature in a wide temperature range reveals the size distribution of the DyAl 2 nanoparticles. The magnetic-entropy changes are derived from the isothermal magnetization curves measured at different temperatures. The magnetic-entropy change of the DyAl 2 nanoparticles is lower than that of the bulk DyAl 2 material but has a broadened peak

Search for superdeformed bands in {sup 154}Dy

Energy Technology Data Exchange (ETDEWEB)

Nisius, D.; Janssens, R.V.F.; Khoo, T.L. [and others

1995-08-01

The island of superdeformation in the vicinity of the doubly magic {sup 152}Dy yrast superdeformed (SD) band is thought to be well understood in the framework of cranked mean field calculations. In particular, the calculations suggested that in {sup 154}Dy there should be no yrast or near yrast SD minimum in the 40-60 h spin range, where SD bands in this mass region are thought to be {sup 153}Dy nucleus, it is populated. However, with the presence of five SD bands in the neighboring necessary to ascertain if the addition of one single neutron diminishes the importance of shell effects to the extent that superdeformation can no longer be sustained. In an experiment utilizing the increased resolving power of the early implementation phase of Gammasphere, the reaction {sup 122}Sn({sup 36}S,4n) at 165 MeV was employed to populate high spin states in {sup 154}Dy. In a four-day run with 36 detectors, over one billion triple and higher fold coincidence events were recorded. One new SD band was identified and was assigned to {sup 154}Dy. From comparisons with the Im{sup (2)} moments of inertia of the SD bands in {sup 152}Dy and {sup 153}Dy, a configuration based on (514)9/2{sup 2} neutrons coupled to the {sup 152}Dy SD core was proposed. One unexpected and as yet unexplained feature of this new SD band is that the transition energies are almost identical to those of an excited SD band in {sup 153}Dy. It is also worth noting that the feeding of the yrast states is similar to that achieved by the deexcitation from the ensemble of all entry states in the reaction. This observation emphasizes the statistical nature of the decay-out process. A paper reporting these results was accepted for publication.

Room-temperature ferromagnetism in Dy films doped with Ni

Energy Technology Data Exchange (ETDEWEB)

Edelman, I. [Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation)], E-mail: ise@iph.krasn.ru; Ovchinnikov, S. [Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Siberian Federal University, Av. Svobodnyi 71, Krasnoyarsk 660074 (Russian Federation); Markov, V.; Kosyrev, N.; Seredkin, V.; Khudjakov, A.; Bondarenko, G. [Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Kesler, V. [Institute of Semiconductor Physics, Siberian Division, Russian Academy of Sciences, Av. Akademika Lavrent' eva 13, Novosibirsk 630090 (Russian Federation)

2008-09-01

Temperature, magnetic field and spectral dependences of magneto-optical effects (MOEs) in bi-layer films Dy{sub (1-x)}Ni{sub x}-Ni and Dy{sub (1-x)}(NiFe){sub x}-NiFe were investigated, x changes from 0 to 0.06. Peculiar behavior of the MOEs was revealed at temperatures essentially exceeding the Curie temperature of bulk Dy which is explained by the magnetic ordering of the Dy layer containing Ni under the action of two factors: Ni impurities distributed homogeneously over the whole Dy layer and atomic contact of this layer with continues Ni layer. The mechanism of the magnetic ordering is suggested to be associated with the change of the density of states of the alloy Dy{sub (1-x)}Ni{sub x} owing to hybridization with narrow peaks near the Fermi level character for Ni.

Buffer layers and articles for electronic devices

Science.gov (United States)

Paranthaman, Mariappan P.; Aytug, Tolga; Christen, David K.; Feenstra, Roeland; Goyal, Amit

2004-07-20

Materials for depositing buffer layers on biaxially textured and untextured metallic and metal oxide substrates for use in the manufacture of superconducting and other electronic articles comprise RMnO.sub.3, R.sub.1-x A.sub.x MnO.sub.3, and combinations thereof; wherein R includes an element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, and A includes an element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Ra.

Accurate masses of unstable rare earth isotopes by ISOLTRAP

International Nuclear Information System (INIS)

Beck, D.; Ames, F.; Audi, G.

2000-05-01

Direct mass measurements of neutron-deficient rare earth isotopes in the vicinity of 146 Gd were performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. This paper reports on the measurement of more than 40 isotopes of the elements Pr, Nd, Pm, Sm, Eu, Dy and Ho, that have been measured with a typical accuracy of δm ∼ 14 keV. An atomic mass evaluation has been performed taking into account other experimental mass values via a least-squares adjustment. The results of the adjustment are discussed. (orig.)

Some Limitations in the Use of Plastic and Dyed Plastic Dosimeters

DEFF Research Database (Denmark)

Miller, Arne; Bjergbakke, Erling; McLaughlin, W. L.

1975-01-01

Several practical plastic and dyed plastic dosimeters were examined under irradiation conditions similar to those used for radiation processing of materials. Cellulose triacetate, polymethyl methacrylate, polyvinyl chloride, dyed polymethyl methacrylate, dyed Cellophane and dyed Nylon were given...

Cytotoxic and genotoxic effect of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system in mice

Energy Technology Data Exchange (ETDEWEB)

Pedraza-Lopez, Martha [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico); Ferro-Flores, Guillermina [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, Ocoyoacac, Estado de Mexico, CP 52045 (Mexico); Arteaga de Murphy, Consuelo [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico)]. E-mail: consuelo_murphy@yahoo.com.mx; Morales-Ramirez, Pedro [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca, Ocoyoacac, Estado de Mexico, CP 52045 (Mexico); Piedras-Ross, Josefa [Departamento de Medicina Nuclear, Instituto Nacional de Ciencias Medicas y Nutricion, Salvador Zubiran, Delegacion Tlalpan, Mexico DF 14000 (Mexico); Murphy-Stack, Eduardo [Hospital Santaelena, Mexico DF (Mexico); Hernandez-Oviedo, Omar [Escuela Superior de Fisica y Matematicas, IPN, Mexico DF (Mexico)

2004-11-01

Multiple myeloma and other hematological malignancies have been treated by myeloablative radiotherapy/chemotherapy and subsequent stem cell transplantation. [{sup 166}Dy]Dy/{sup 166}Ho-ethylenediaminetetramethylene phosphonate (EDTMP) forms a stable in vivo generator system with selective skeletal uptake in mice; therefore, it could work as a potential and improved agent for marrow ablation. Induced bone marrow cytotoxicity and genotoxicity are determined by the reduction of reticulocytes (RET) and elevation of micronucleated reticulocyte (MN-RET) in peripheral blood and ablation by bone marrow histological studies. The aim of this study was to determine the bone marrow cytotoxic and genotoxic effect of the [{sup 166}Dy]Dy/{sup 166}Ho-EDTMP in vivo generator system in mice and to evaluate by histopathology its myeloablative potential. Enriched {sup 166}Dy{sub 2}O{sub 3} was irradiated and [{sup 166}Dy]DyCl{sub 3} was added to EDTMP in phosphate buffer (pH 8.0) in a molar ratio of 1:1.75. QC was determined by TLC. Dy-EDTMP complex was prepared the same way with nonirradiated dysprosium oxide. A group of BALB/c mice were intraperitoneally injected with the radiopharmaceutical and two groups of control animals were injected with the cold complex and with 0.9% sodium chloride, respectively. A blood sample was taken at the beginning of the experiments and every 48 h for 12 days postinjection. The animals were sacrificed, organs of interest taken out and the radioactivity determined. The femur was used for histological studies. Flow cytometry analysis was used to quantify the frequency of RET and MN-RET in the blood samples. The MCNP4B Monte Carlo computer code was used for dosimetry calculations. Radiochemical purity was 99% and the mean specific activity was 1.3 MBq/mg. The RET and MN-RET frequency were statistically different in the treatment at the end of the 12-day period demonstrating cytotoxicity and genotoxicity induced by the in vivo generator system. The

Microstructures and mechanical properties of Mg–Zn–Zr–Dy ...

Indian Academy of Sciences (India)

Microstructures and phase compositions of as-cast and extruded ZK60–Dy ( = 0–5) alloys were analysed by optical microscope, scanning electron microscope, X-ray diffraction and differential scanning calorimetry. Meanwhile, the tensile mechanical property was tested.With increasing Dy content, Mg–Zn–Dy new phase ...

Dependence of red thermoluminescence on Eu-anomaly in natural quartzes

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, T; Yokosaka, K; Notoya, S; Ojima, T; Sakaue, S [Niigata Univ. (Japan). Faculty of Science

1993-04-01

The causes of red colour thermoluminescence (RTL) from natural quartz have been sought in the presence of impurity elements. Some impurities in 31 varieties of natural quartz extracts, determined by a neutron activation analysis, have been examined with respect to a meaningful correlation of the RTL to the total detectable TL strength. Generally, the higher impurity contents were found in quartz of volcanic origin, which always emits purely RTL colour, whereas the lower impurities were usually detected in hydrothermal quartz, which emits purely blue TL (BTL) in all absorbed doses. Among the impurities, the middle REE (rare earth elements), involving Eu and Sm, particularly offered considerable correlation with RTL emission with the exception of pegmatite quartz. It was found from the chondrite-normalized REE patterns that a positive Eu anomaly or flattened Eu distribution gave rise to relatively high RTL proportions, while a negative Eu anomaly always showed extremely weak RTL intensity. Thus, it was concluded that the Eu[sup 3+], formed from the oxidizable surrounding or high oxygen fugacity relative to a Cl chondrite formation, is strongly related to the RTL intensity in natural quartz. (author).

Effect of rare-earth ion size on local electron structure in RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (R = Tm, Dy, Gd, Eu, Nd and Y) superconductors: A positron study

Energy Technology Data Exchange (ETDEWEB)

Chen Zhenping [Department of Technology and Physics, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, Henan 450002 (China)]. E-mail: czhping@zzuli.edu.cn; Zhang Jincang [Department of Physics, Shanghai University, Shanghai 200436 (China); Su Yuling [Department of Technology and Physics, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, Henan 450002 (China); Xue Yuncai [Department of Technology and Physics, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, Henan 450002 (China); Cao Shixun [Department of Physics, Shanghai University, Shanghai 200436 (China)

2006-02-15

The effects of rare-earth ionic size on the local electron structure, lattice parameters and superconductivity have been investigated by positron annihilation technique (PAT) and related experiments for RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (R = Tm, Dy, Gd, Eu, Nd and Y) superconductors. The local electron density n {sub e} is evaluated as a function of the rare-earth radius. The results show that both the bulk-lifetime {tau} {sub B} and the defect lifetime {tau} {sub 2} increase with increasing rare-earth ionic radius, while the local electron density n {sub e} decrease with increasing rare-earth ionic radius. These results prove that the changes of n {sub e}, the degree of orthorhombic distortion and the coupling between the Cu-O chains and the CuO{sub 2} planes all have an effect on the superconductivity of RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} systems.

Therapeutical radiopharmaceuticals based In vivo generator system [166 Dy] Dy/166 Ho

International Nuclear Information System (INIS)

Ferro F, G.; Garcia S, L.; Monroy G, F.; Tendilla, J.I.; Pedraza L, M.; Murphy, C.A. de

2002-01-01

At the idea to administer to a patient a molecule containing in it structure a father radionuclide, with a half life enough large which allows to the radiolabelled molecule to take up position specifically in a white tissue and decaying In vivo to the daughter radionuclide with properties potentially therapeutic, it is known as In vivo generator system. In this work the preparation and the preliminary dosimetric valuations of radiopharmaceuticals based In vivo generator system 166 Dy Dy/ 166 Ho for applications in radioimmunotherapy, in the treatment of the rheumatoid arthritis and in the bone marrow ablation (m.o.) for candidates patients to bone marrow transplant are presented. (Author)

Mobility of rare earth element in hydrothermal process and weathering product: a review

Science.gov (United States)

Lintjewas, L.; Setiawan, I.

2018-02-01

The Rare Earth Element (REE), consists of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Lu, Ho, Er, Tm, Yb, are important elements to be used as raw materials of advanced technology such as semiconductors, magnets, and lasers. The research of REE in Indonesia has not been done. Several researches were conducted on granitic rocks and weathering product such as Bangka, Sibolga, West Kalimantan, West Sulawesi and Papua. REE can be formed by hydrothermal processes such as Bayan Obo, South China. The REE study on active hydrothermal system (geothermal) in this case also has the potential to produce mineral deposits. The purpose of this review paper is to know the mobility of REE on hydrothermal process and weathering products. Mobility of REE in the hydrothermal process can change the distribution patterns and REE content such as Ce, Eu, La, Lu, Nd, Sm, and Y. Another process besides the hydrothermal is weathering process. REE mobility is influenced by weathering products, where the REE will experience residual and secondary enrichment processes in heavier minerals.

TL dosimetric characterization of gamma irradiated SrSO{sub 4}:Eu phosphors

Energy Technology Data Exchange (ETDEWEB)

Jayasudha, S., E-mail: jsnair.india@gmail.com [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India); Madhukumar, K.; Nair, C.M.K.; Nair, Resmi G. [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India); Rajesh, S. [Department of Materials & Ceramic Engineering, University of Aveiro, Aveiro 3810-193 (Portugal); Elias, T.S. [State Institute of Cancer Research, Medical College P.O., Thiruvananthapuram 695011 (India); Anandakumar, V.M. [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India); State Institute of Cancer Research, Medical College P.O., Thiruvananthapuram 695011 (India); Department of Materials & Ceramic Engineering, University of Aveiro, Aveiro 3810-193 (Portugal); Gopakumar, N. [Mahatma Gandhi College, Kesavadasapuram, Pattom Palace P.O., Thiruvananthapuram 695004 (India)

2017-03-15

Thermoluminescence (TL) characteristics of SrSO{sub 4}:Eu nanostructured phosphor under gamma excitation has been studied and their suitability for environmental radiation dosimetry applications is discussed. The dopant level is tuned for optimum TL response. The effect of radiation dose and heating rate were investigated. The phosphor preserves linearity in the low dose region, 0.1 Gy to 20 Gy. PL studies of irradiated and un-irradiated phosphors reveal that the dopant Eu exists in divalent state and are the luminescence emission centres in the material. The fading properties of SrSO{sub 4}:Eu phosphor are observed to be better than that of the commercial dosimeters TLD-200 and TLD-400. The kinetic parameters are calculated using Chen's method and initial rise method and verified by Computerized Glow curve Deconvolution (CGCD). The sensitivity of the synthesized phosphor is found to be very high when compared with that of the commercial standard dosimeter CaSO{sub 4}:Dy. The phosphor is found to be stable for short term radiation monitoring.

Anisotropic magnetization and transport properties of RAgSb₂ (R=Y, La-Nd, Sm, Gd-Tm)

Energy Technology Data Exchange (ETDEWEB)

Myers, Kenneth D. [Iowa State Univ., Ames, IA (United States)

1999-11-08

This study of the RAgSb₂ series of compounds arose as part of an investigation of rare earth intermetallic compounds containing antimony with the rare earth in a position with tetragonal point symmetry. Materials with the rare earth in a position with tetragonal point symmetry frequently manifest strong anisotropies and rich complexity in the magnetic properties, and yet are simple enough to analyze. Antimony containing intermetallic compounds commonly possess low carrier densities and have only recently been the subject of study. Large single grain crystals were grown of the RAgSb₂ (R=Y, La-Nd, Sm, Gd-Tm) series of compounds out of a high temperature solution. This method of crystal growth, commonly known as flux growth is a versatile method which takes advantage of the decreasing solubility of the target compound with decreasing temperature. Overall, the results of the crystal growth were impressive with the synthesis of single crystals of LaAgSb₂ approaching one gram. However, the sample yield diminishes as the rare earth elements become smaller and heavier. Consequently, no crystals could be grown with R=Yb or Lu. Furthermore, EuAgSb₂ could not be synthesized, likely due to the divalency of the Eu ion. For most of the RAgSb₂ compounds, strong magnetic anisotropies are created by the crystal electric field splitting of the Hund's rule ground state. This splitting confines the local moments to lie in the basal plane (easy plane) for the majority of the members of the series. Exceptions to this include ErAgSb₂ and TmAgSb₂, which have moments along the c-axis (easy axis) and CeAgSb₂, which at intermediate temperatures has an easy plane, but exchange coupling at low temperatures is anisotropic with an easy axis. Additional anisotropy is also observed within the basal plane of DyAgSb₂, where the moments are restricted to align along one of the <110> axes. Most of

Evaluation of Ablation rate by the change of Sacrificial Material for PECS in EU-APR

Energy Technology Data Exchange (ETDEWEB)

Hwang, Do Hyun; Kim, Yong Soo; Lee, Keun Sung [KHNP-CRI, Daejeon (Korea, Republic of)

2015-05-15

EU-APR, modified and improved from its original design of APR1400, has been developed to comply with European Utility Requirements (EUR) and nuclear design requirements of the European countries. In EU-APR, Severe Accident Mitigation Systems are dedicated to providing an independent defense line from that of Engineered Safety Feature (ESF) and Diverse Safety Feature (DSF). They consist of Emergency Reactor Depressurization System (ERDS), Passive Ex-vessel corium retaining and Cooling System (PECS), Severe Accident Containment Spray System (SACSS), Hydrogen Mitigation System (HMS) and Containment Filtered Vent System (CFVS). The PECS, so called core catcher, was introduced to prevent the Molten Core Concrete Interaction (MCCI) after Reactor Vessel (RV) failure. The PECS has experienced a lot of changes from its original design. Recently, the most significant change was that as a SM, limestone concrete is installed on PECS's body wall instead of previous sacrificial material rich in Fe{sub 2}O{sub 3}. The main reason of this design change is to overcome the issue that the sacrificial material is ablated rather too fast when reacting with corium that contains a large fraction of Zr metal. Other changes in the geometry of PECS's wall and downcomer design are considered as minor ones. In this paper, the comparison of ablation rates between previous SM and limestone concrete is carried out using MAAP5 code with respective MCCI model according to the material. In this paper, major improvements of MAAP5 model for PECS in EU-APR are presented and the evaluation of ablation rate for the previous SM model and the new LC model is carried out by means of ablation depths with LBLOCA sequence. Two models have respective unique ablation process. The ablation of LC model proceeds at a constant rate regardless of water while the ablation of SM model proceeds at a faster rate before the arrival of cooling water for corium and SM mixture. The change of sacrificial material

CaSO4: Dy + Teflon thermoluminescent dosemeters

International Nuclear Information System (INIS)

Campos, L.L.

1986-01-01

A pellet dosemeter of CaSO 4 : Dy + Teflon was developed at IPEN. CaSO 4 : Dy thermoluminescent phosphor, grown in the Dosimetric Materials Production Laboratory was chosen, due to its high sensitivity, ease of preparation and comparatively low cost. Pellets were produced by cold pressing and sintering a mixture of CaSO 4 : Dy and Teflon powders. Extensive work was done to study in detail all CaSO 4 : Dy pellets characteristics from the point of view of dosimetry with the purpose of introducing it in the routine use. A filter combination providing an energy independent response from 20 KeV to 1,25 MeV was obtained. The dosemeter consists of three pellets sealed between two thin plastic sheets and placed under plastic and lead filters. The combination of these tree filters allows the exposure as well as the energy determination of an unknown source. (Author) [pt

Physical properties of superbulky lanthanide metallocenes: synthesis and extraordinary luminescence of [Eu(II)(Cp(BIG))2] (Cp(BIG) = (4-nBu-C6H4)5-cyclopentadienyl).

Science.gov (United States)

Harder, Sjoerd; Naglav, Dominik; Ruspic, Christian; Wickleder, Claudia; Adlung, Matthias; Hermes, Wilfried; Eul, Matthias; Pöttgen, Rainer; Rego, Daniel B; Poineau, Frederic; Czerwinski, Kenneth R; Herber, Rolfe H; Nowik, Israel

2013-09-09

The superbulky deca-aryleuropocene [Eu(Cp(BIG))2], Cp(BIG) = (4-nBu-C6H4)5-cyclopentadienyl, was prepared by reaction of [Eu(dmat)2(thf)2], DMAT = 2-Me2N-α-Me3Si-benzyl, with two equivalents of Cp(BIG)H. Recrystallizyation from cold hexane gave the product with a surprisingly bright and efficient orange emission (45% quantum yield). The crystal structure is isomorphic to those of [M(Cp(BIG))2] (M = Sm, Yb, Ca, Ba) and shows the typical distortions that arise from Cp(BIG)⋅⋅⋅Cp(BIG) attraction as well as excessively large displacement parameter for the heavy Eu atom (U(eq) = 0.075). In order to gain information on the true oxidation state of the central metal in superbulky metallocenes [M(Cp(BIG))2] (M = Sm, Eu, Yb), several physical analyses have been applied. Temperature-dependent magnetic susceptibility data of [Yb(Cp(BIG))2] show diamagnetism, indicating stable divalent ytterbium. Temperature-dependent (151)Eu Mössbauer effect spectroscopic examination of [Eu(Cp(BIG))2] was examined over the temperature range 93-215 K and the hyperfine and dynamical properties of the Eu(II) species are discussed in detail. The mean square amplitude of vibration of the Eu atom as a function of temperature was determined and compared to the value extracted from the single-crystal X-ray data at 203 K. The large difference in these two values was ascribed to the presence of static disorder and/or the presence of low-frequency torsional and librational modes in [Eu(Cp(BIG))2]. X-ray absorbance near edge spectroscopy (XANES) showed that all three [Ln(Cp(BIG))2] (Ln = Sm, Eu, Yb) compounds are divalent. The XANES white-line spectra are at 8.3, 7.3, and 7.8 eV, for Sm, Eu, and Yb, respectively, lower than the Ln2O3 standards. No XANES temperature dependence was found from room temperature to 100 K. XANES also showed that the [Ln(Cp(BIG))2] complexes had less trivalent impurity than a [EuI2(thf)x] standard. The complex [Eu(Cp(BIG))2] shows already at room temperature

Hyperfine fields of Fe in Nd2Fe14BandSm2Fe17N3

Science.gov (United States)

Akai, Hisazumi; Ogura, Masako

2015-03-01

High saturation magnetization of rare-earth magnets originates from Fe and the strong magnetic anisotropy stems from f-states of rare-earth elements such as Nd and Sm. Therefore the hyperfine fields of both Fe and rare-earth provide us with important pieces of information: Fe NMR enable us to detect site dependence of the local magnetic moment and magnetic anisotropy (Fe sites also contribute to the magnetic anisotropy) while rare-earth NQR directly give the information of electric field gradients (EFG) that are related to the shape of the f-electron cloud as well as the EFG produced by ligands. In this study we focus on the hyperfine fields of materials used as permanent magnets, Nd2Fe14BandSm2Fe17N3 from theoretical points of view. The detailed electronic structure together with the hyperfine interactions are discussed on the basis of the first-principles calculation. In particular, the relations between the observed hyperfine fields and the magnetic properties are studies in detail. The effects of doping of those materials by other elements such as Dy and the effects of N adding in Sm2Fe17N3 will be discussed. This work was supported by Elements Strategy Initiative Center for Magnetic Materials Project, the Ministry of Education, Culture, Sports, Science and Technology, Japan.

Band mixing in /sup 160/Dy

Energy Technology Data Exchange (ETDEWEB)

Hasiza, M L; Singh, K; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

1982-11-01

The intensities of the gamma transitions in /sup 160/Dy have been measured precisely by a 45 cc Ge(Li) detector. Unequal quadrupole moments for the ground and gamma vibrational bands have been proposed in order to remove the inconsistencies in the values of band mixing parameter Z sub(gamma) for this doubly even deformed nucleus of /sup 160/Dy.

Rare earth and precious elements in the urban sewage sludge and lake surface sediments under anthropogenic influence in the Republic of Benin.

Science.gov (United States)

Yessoufou, Arouna; Ifon, Binessi Edouard; Suanon, Fidèle; Dimon, Biaou; Sun, Qian; Dedjiho, Comlan Achille; Mama, Daouda; Yu, Chang-Ping

2017-11-09

Nowadays, sewage sludge and water bodies are subjected to heavy pollution due to rapid population growth and urbanization. Heavy metal pollution represents one of the main challenges threatening our environment and the ecosystem. The present work aims to evaluate the contamination state of the sewage sludge and lake sediments in the Republic of Benin. Twenty metallic elements including 15 rare earth elements (Eu, Sb, Cs, Nd, Pr, Gd, La, Ce, Tb, Sm, Dy, Ho, Eu, Yb, and Lu) and five precious elements (Ag, Au, Pd, Pt, and Ru) were investigated using inductive plasma-mass spectrometry. Results showed broad range concentrations of the elements. Ce, La, and Nd were present in both sediments and sewage sludge at concentrations ranging 5.80-41.30 mg/kg dry matter (DM), 3.23-15.60 mg/kg DM, and 2.74-19.26 mg/kg DM, respectively. Pr, Sm, Gd, Tb, Dy, Eu, Er, Yb, Cs, Ho, and Tm concentrations were lower (0.02-5.94 mg/kg DM). Among precious elements, Ag was detected at the highest concentration in all sites (0.43-4.72 mg/kg DM), followed by Pd (0.20-0.57 mg/kg DM) and Au (0.01-0.57 mg/kg DM). Ru and Pt concentrations were sewage sludge. This revealed a growing anthropogenic input which was also implied by principal component analysis. The evaluation of pollution loading index (PLI) indicated a moderate to strong contamination (0.12 ≤ PLI ≤ 0.58; 37 ≤ PLI ≤ 114, respectively, for rare earth elements and precious elements), while the degree of contamination indicated a moderate polymetallic contamination for rare earth elements and significant contamination for precious elements.

Interband transitions in 106Pd, 152Sm, 152Gd and 182W

International Nuclear Information System (INIS)

Kartashov, V.M.; Oborovskij, A.I.; Troitskaya, A.G.

1990-01-01

Internal transitions in 106 Pd, 152 Sm, 152 Gd, 182 W nuclei, observed during decay of 152,152m Eu, 182,183 Ta, 106m Ag, are studied. The experimental characteristics of E0-transitions and E0-components of E0+M1+E2 type transitions in the studied nuclei, relative intensities of internal conversion electron lines during 182 Ta decay, multipolar composition and forbidden factor for 182 W and 183 W low-energy transitions, characteristics of transitions are presented

Study of the nuclear structure of {sup 155}Eu; Estudo da estrutura nuclear do {sup 155}Eu

Energy Technology Data Exchange (ETDEWEB)

Genezini, Frederico Antonio

2004-07-01

The {sup 155}Eu nuclide was investigated by the directional angular correlation technique following the {beta} decay of {sup 155}Sm. The angular correlation measurements were carried out using a setup with 4 Ge detectors and a multi parametric data acquisition system. To perform the data analysis a new methodology was developed . The multipole mixing ratios of twenty sixty {gamma}- transitions were determined. Seven of them agreed with the results of earlier angular correlation studies and nineteen obtained for the first time confirmed the multipolarity suggested in earlier electron capture studies. Besides, the spin of the level at 1106.83 keV as well as the parity of the level at 1301.41 keV have also been suggested. The nuclear structure of {sup 155}Eu was discussed successfully in terms of the single particle model using a deformed Woods-Saxon potential plus residual pairing interaction permitting the description of the rotational quasi-proton band heads. (author)

Coercivity enhancement in hot deformed Nd2Fe14B-type magnets by doping low-melting RCu alloys (R = Nd, Dy, Nd + Dy)

Science.gov (United States)

Lee, Y. I.; Huang, G. Y.; Shih, C. W.; Chang, W. C.; Chang, H. W.; You, J. S.

2017-10-01

Magnetic properties of the anisotropic NdFeB magnets prepared by hot pressing followed by die-upsetting NdFeB MQU-F powders doped with low-melting RCu alloy powders were explored, where RCu stands for Nd70Cu30, Dy70Cu30 and (Nd0.5Dy0.5)70Cu30, respectively. In addition, the post-annealing at 600 °C was employed to modify the microstructures and the magnetic properties of the hot deformed magnets. It is found that doping RCu alloy powders is effective in enhancing the coercivity of the hot deformed NdFeB magnets from 15.1 kOe to 16.3-19.5 kOe. For Nd70Cu30-doped magnets, the increment of coercivity is only 1.2 kOe. Meanwhile, Dy70Cu30-doped and (Nd0.5Dy0.5)70Cu30-doped magnets show an almost identical enhancement of coercivity of about 4.4 kOe. Importantly, the latter magnet shows a beneficial effect of reducing the usage of Dy from 1.6 wt% to 0.8 wt%. TEM analysis shows that nonmagnetic Nd, Dy and Cu appear at grain boundary and isolate the magnetic grains, leading to an enhancement of coercivity. Doping lower melting point Dy-lean (Nd0.5Dy0.5)70Cu30 powders into commercial MQU-F powders for making high coercivity hot deformed NdFeB magnets might be a potential and economic way for mass production.

Rotational and translational distortions of the crystal structure of the Sr{sub 2}HrRuO{sub 6} (Hr = Ho, Dy, Gd, Eu) complex perovskites

Energy Technology Data Exchange (ETDEWEB)

Triana, C.A., E-mail: ctrianae@unal.edu.co [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia); Landínez Téllez, D.A. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia); Roa-Rojas, J., E-mail: jroar@unal.edu.co [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá D.C. (Colombia)

2013-05-15

Sr{sub 2}HrRuO{sub 6} (Hr = Ho, Dy, Gd, Eu) complex perovskites were synthesized through the high-temperature solid-state reaction method, and their crystal structures were analyzed in detail as a function of the Hr-cation ionic radius. Results of powder XRD pattern measurement and Rietveld analysis of the experimental profiles show that the Sr{sub 2}HrRuO{sub 6} compounds crystallize in a monoclinic distorted perovskite-like structure, P2{sub 1}/n (#14) space group, where the unit cell parameters are related to the primitive unit cell a{sub p} by a≈√(2)a{sub p}, b≈√(2)a{sub p} and c ≈ 2a{sub p}. The structures show an alternate distribution of the Ru{sup 5+} (2d: 0.5, 0, 0) and Hr{sup 3+} (2c: 0, 0.5, 0) making up RuO{sub 6} and HrO{sub 6} octahedra alternatively arranged in two interleaving fcc sublattices, where the O(1), O(2), and O(3) ions are localized at the corner of the octahedral, while the Sr{sup 2+} is located at the A-site, occupying the cavities built by the corner-sharing octahedra with Wyckoff position 4e. Due to the existence of mismatched ionic sizes between the ionic radii of the Sr{sub 2}HrRuO{sub 6} compounds, the HrO{sub 6} and RuO{sub 6} octahedra are constrained to tilting around the [111]{sub c}, [001]{sub c}, and [110]{sub c} cubic directions so as to optimize the Sr–O inter-atomic bond lengths, tending to rotate the structure in order to fix the Ru{sup 5+} and Hr{sup 3+} ions on the M′ and M″ sites of the complex perovskites. The cell parameters a, b, and c, the inter-atomic bond angles, the inter-atomic bond lengths, and the tilting angles increase as the Hr-cation ionic radius increases. The mismatch that exists in the Sr{sub 2}HrRuO{sub 6} ionic radius produces a large distortion from the ideal cubic symmetry. The pure perovskite-like phase of Sr{sub 2}HrRuO{sub 6} is thermodynamically and kinetically stable at high temperatures above 1420 K, where it is entirely governed by the average size of the Hr{sup 3+} and Ru

Evaluation of Radioisotope Production Process of 153Sm and 153Sm-EDTMP Radiopharmaceuticals

International Nuclear Information System (INIS)

Kadarisman; Sri Hastini; Yayan Tahyan; Abidin; Dadang Hafid; Enny Lestari

2007-01-01

Experiments on the process of 153 Sm radioisotope and labeling of 153 Sm-EDTMP radiopharmaceuticals were carried out. This experiments included preparation of Sm 2 O 3 target, dissolution of post irradiation, determination of radioactivity concentration of 153 Sm radioisotope, radionuclide purity, EDTMP labeling, determination of radiochemical purity and pH. In these experiments the total radioactivity 153 Sm product is round about 2845.83 mCi to 36963.31 mCi, or with the radioactivity concentration between 474 mCi/ml to 6160.55 mCi/ml in the SmCl 3 solution form, each its volume is 6.0 ml, and the samarium content is 5.76 mg/ml, and the radionuclide purity of 153 Sm is 100 %. All of the 153 Sm- EDTMP radiopharmaceuticals product are fulfilled requirements the radioactivity concentration, Sm content, radiochemical purity and pH. The radioactivity concentration of 153 Sm-EDTMP radiopharmaceuticals is 37.50 mCi/ml (minimum) to 283.50 mCi/ml (highest). The pH 7.5 were 8 products, and the rest are pH 8.5. Radiochemical purity of 153 Sm-EDTMP are round about 90.00 % to 99.44 %. (author)

Application of Sm/Eu/, Rb/Sr, Ce/Yb and F-Rb ratios to discriminate between Tin mineralized and non-mineralized S-type granites

International Nuclear Information System (INIS)

Karimpour, M.H.

1998-01-01

Mash had granites and Gran diorites are divided into three groups bas sed on their ages and composition: (1) Deh Now-Vakilabad-Kuhsangi Granodiorites and Quartz monzodiorites, (2) Sang bast Granite and (3) Khalaj- Gheshlagh Biotite-muscovite Granite. All these intrusive s belong to S-type granite, The oldest are in the range of intermediate and the youngest are acidic in composition. Intrusive rocks in the area of Deh now to Kuhsangi show trend of differentiation. Major, trace and rare earth elements within the source rocks of porphyry Sn, Mo, and Cu deposits were compared and very distinct differences were noticed. Differentiation index, Rb/Sr, Ce/Yb, and (Sr 87 /Sr 86 ) ratios can be used to identify the source rocks for porphyry Sn, Mo, or Cu. Major, as well as trace and rare earth elements of Mash had Granites and Granodiorites were compared with tin mineralized granites of the world. As a result, four diagrams were presented to be utilized in order to discriminate between Sn mineralized and non-mineralized granites. Such as Rb to the ratio of Sm/Eu, F to Rb and the three angle of F, Rb, Sr + Ba

Distribution behavior of uranium, neptunium, rare-earth elements (Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiCl-KCl eutectic salt and liquid cadmium or bismuth

International Nuclear Information System (INIS)

Kurata, M.; Sakamura, Y.; Hijikata, T.; Kinoshita, K.

1995-01-01

Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCl eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl/Bi system were by one or two orders of magnitude larger than those in the LiCl-KCl/Cd system. On the contrary, the separation factors of alkaline-earth metals and divalent rare-earth elements to trivalent rare-earth elements were by one or two orders of magnitude smaller in the LiCl-KCl/Bi system. (orig.)

Modeling of melt retention in EU-APR1400 ex-vessel core catcher

Energy Technology Data Exchange (ETDEWEB)

Granovsky, V. S.; Sulatsky, A. A.; Khabensky, V. B.; Sulatskaya, M. B. [Alexandrov Research Inst. of Technology NITI, Sosnovy Bor (Russian Federation); Gusarov, V. V.; Almyashev, V. I.; Komlev, A. A. [Saint Petersburg State Technological Univ. SPbSTU, St.Petersburg (Russian Federation); Bechta, S. [KTH, Stockholm (Sweden); Kim, Y. S. [KHNP, 1312 Gil 70, Yuseongdaero, Yuseong-gu, Daejeon (Korea, Republic of); Park, R. J.; Kim, H. Y.; Song, J. H. [KAERI, 989 Gil 111, Daedeokdaero, Yuseong-gu, Daejeon (Korea, Republic of)

2012-07-01

A core catcher is adopted in the EU-APR1400 reactor design for management and mitigation of severe accidents with reactor core melting. The core catcher concept incorporates a number of engineering solutions used in the catcher designs of European EPR and Russian WER-1000 reactors, such as thin-layer corium spreading for better cooling, retention of the melt in a water-cooled steel vessel, and use of sacrificial material (SM) to control the melt properties. SM is one of the key elements of the catcher design and its performance is critical for melt retention efficiency. This SM consists of oxide components, but the core catcher also includes sacrificial steel which reacts with the metal melt of the molten corium to reduce its temperature. The paper describes the required properties of SM. The melt retention capability of the core catcher can be confirmed by modeling the heat fluxes to the catcher vessel to show that it will not fail. The fulfillment of this requirement is demonstrated on the example of LBLOCA severe accident. Thermal and physicochemical interactions between the oxide and metal melts, interactions of the melts with SM, sacrificial steel and vessel, core catcher external cooling by water and release of non-condensable gases are modeled. (authors)

Therapeutical radiopharmaceuticals based In vivo generator system [{sup 166} Dy] Dy/{sup 166} Ho; Radiofarmacos terapeuticos basados en un sistema de generador In vivo [{sup 166}Dy] Dy/{sup 166}Ho

Energy Technology Data Exchange (ETDEWEB)

Ferro F, G.; Garcia S, L.; Monroy G, F.; Tendilla, J.I. [Gerencia de Aplicaciones Nucleares en la Salud, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Pedraza L, M.; Murphy, C.A. de [Departamento de Medicina Nuclear, Instituto Nacional de Pediatria, Mexico D.F. (Mexico)

2002-07-01

At the idea to administer to a patient a molecule containing in it structure a father radionuclide, with a half life enough large which allows to the radiolabelled molecule to take up position specifically in a white tissue and decaying In vivo to the daughter radionuclide with properties potentially therapeutic, it is known as In vivo generator system. In this work the preparation and the preliminary dosimetric valuations of radiopharmaceuticals based In vivo generator system {sup 166} Dy Dy/{sup 166} Ho for applications in radioimmunotherapy, in the treatment of the rheumatoid arthritis and in the bone marrow ablation (m.o.) for candidates patients to bone marrow transplant are presented. (Author)

Properties of alginate fiber spun-dyed with fluorescent pigment dispersion.

Science.gov (United States)

Wang, Ping; Tawiah, Benjamin; Tian, Anli; Wang, Chunxia; Zhang, Liping; Fu, Shaohai

2015-03-15

Spun-dyed alginate fiber was prepared by the spun-dyeing method with the mixture of fluorescent pigment dispersion and sodium alginate fiber spinning solution, and its properties were characterized by SEM, TGA, DSC, and XRD. The results indicate that fluorescent pigment dispersion prepared with esterified poly (styrene-alt maleic acid) had excellent compatibility with sodium alginate fiber spinning solution, and small amount of fluorescent pigment could reduce the viscosity of spun-dyed spinning solutions. SEM photo of spun-dyed alginate fiber indicated that fewer pigment particles deposited on its surface. TGA, DSC, and XRD results suggested that thermal properties and crystal phase of spun-dyed alginate fibers had slight changes compared to the original alginate fibers. The fluorescence intensity of spun-dyed alginate fiber reached its maximum when the content of fluorescent pigment was 4%. The spun-dyed alginate fiber showed excellent rubbing and washing fastness. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electrical and magnetic transport properties of DyTiGe

International Nuclear Information System (INIS)

Dagula, W.; Tegus, O.; Li, X.W.; Zhang, L.; Brueck, E.; Boer, F.R. de; Buschow, K.H.J.

2004-01-01

Electrical resistivity and magnetoresistance of DyTiGe were investigated as a function of temperature and magnetic field. DyTiGe is an antiferromagnet with Neel temperature, T N , of 180 K. The electrical resistivity has an anomaly around T N . Below T N , the magnetoresistance of DyTiGe abruptly changes at a critical field. At 5 K, we observe a magnetoresistance reduction of about 20%

Study of photoluminescence and thermoluminescence properties of BaAl2O4 (Eu2+, Dy3+) phosphor synthesized by solution combustion method

Science.gov (United States)

Pathak, Pushpraj; Kurchania, Rajnish

2016-10-01

Eu and Dy co-doped barium aluminate phosphor was successfully synthesized by combustion method using urea as a fuel. Phase formation was confirmed by powder X-ray diffraction (PXRD) analysis. The calculated average crystallite size was found to be ~34.62 nm. Scanning electron microscopy (SEM) images acquired at different (low and high) magnifications reveal that the crystallites have no uniform shape and size. This was due to the non-uniform distribution of temperature and mass flow in the combustion technique. Fourier Transform Infra-red (FTIR) spectrum was recorded to confirm the phase formation and also to identify any impurity if present in the prepared phosphor. Photoluminescence (PL) measurement was carried out to investigate the incorporation of dopant into the host lattice. Thermoluminescence (TL) behaviour of synthesized phosphor was studied after the irradiation with Cobalt-60 gamma rays (Eavg=1.25 MeV) as well as 6 and 16 MV (Mega Voltage) X-ray photons, at various dose levels. The glow curves of irradiated samples exhibit only one peak at 115 °C at each dose level. With the increases of radiation dose an increase in total intensity has been observed. No appreciable shift in peak positions has been observed. Trapping parameters were evaluated to understand the characteristics of prepared phosphor. A simple glow peak with relatively high intensity is one of the important factors, which make this phosphor useful for monitoring the ionizing radiations in nuclear industries, gamma irradiators, high energy accelerators, nuclear reactors etc. where medium and high level of exposure is involved. It could also be applicable for accidental and retrospective dose assessment.

Production of 147Eu for gamma-ray emission probability measurement

International Nuclear Information System (INIS)

Katoh, Keiji; Marnada, Nada; Miyahara, Hiroshi

2002-01-01

Gamma-ray emission probability is one of the most important decay parameters of radionuclide and many researchers are paying efforts to improve the certainty of it. The certainties of γ-ray emission probabilities for neutron-rich nuclides are being improved little by little, but the improvements of those for proton-rich nuclides are still insufficient. Europium-147 that decays by electron capture or β + -particle emission is a proton-rich nuclide and the γ-ray emission probabilities evaluated by Mateosian and Peker have large uncertainties. They referred to only one report concerning with γ-ray emission probabilities. Our final purpose is to determine the precise γ-ray emission probabilities of 147 Eu from disintegration rates and γ-ray intensities by using a 4πβ-γ coincidence apparatus. Impurity nuclides affect largely to the determination of disintegration rate; therefore, a highly pure 147 Eu source is required. This short note will describe the most proper energy for 147 Eu production through 147 Sm(p, n) reaction. (author)

The application of f-elements in ecological research

International Nuclear Information System (INIS)

Knaus, R.M.

1991-01-01

The utilization of f-elements has a relatively minor status as a research tool in the biological sciences, especially ecology, because they play neither positive nor deleterious roles in plant and animal nutrition. Additionally, detection and quantification via instrumental neutron activation analysis (INAA) of environmental samples is not yet routine. At Louisiana State University, La, Sm, and Dy have been used successfully as activable stable tracers in a wide range of ecological studies including the quantification using Sm and Dy of short-term sedimentary and erosional processes in wetlands; and behavior studies using Sm on agricultural lands where radioisotopes are precluded; the sorption of Dy and La by roots of stream-side trees; and the quantification of exogenous Dy and Sm from animal decay products in streams. With advances in sample automation and standardization in INAA detection methods, the quantification of f-element tracers in complex biological matrices is within reach of ecological scientists

Unexpected structure in the E2 quasicontinuum spectrum of 154Dy

International Nuclear Information System (INIS)

Holzmann, R.; Khoo, T.L.; Ma, W.C.

1988-01-01

The evolution of the γ quasicontinuum spectrum with neutron number has been investigated in the sequence of dysprosium isotopes /sup 152,154,156/Dy. The three nuclei display a pronounced collective E2 component. In 154 Dy this component shows an unexpected splitting into two distinct parts, signifying a structural change along the γ cascade. The E2 and statistical components can be reproduced in simple γ cascade calculations; in 152 Dy and 156 Dy only rotational bands were included, whereas in 154 Dy additional vibration-like transitions were required to reproduce the two E2 peaks. 11 refs., 2 figs

Emission spectra of phosphor MgSO4 doped with Dy and Mn

International Nuclear Information System (INIS)

Zhang Chunxiang; Chen Lixin; Tang Qiang; Luo Daling; Qiu Zhiren

2001-01-01

Emission spectra of phosphor MgSO 4 doped with Dy and Dy/Mn were measured with an optical multichannel analyzer and a linear heating system whose temperature was controlled by a microcomputer. The emission spectrum bands at 480 nm and 580 nm of phosphor MgSO 4 doped with Dy were observed in the three dimensional (3D) glow curves. Compared with the 3D spectrum of CaSO 4 :Dy and the spectrum bands of MgSO 4 :Dy shows the same wavelengths which resulted from the quantum transitions among the energy levels of Dy 3 '+ ions. The intensities of the glow peaks in both spectrum bands (480 nm and 580 nm) of phosphor MgSO 4 doped with Dy/Mn were dramatically reduced except the 380 degree C glow peak

From a Dy(III) single molecule magnet (SMM) to a ferromagnetic [Mn(II)Dy(III)Mn(II)] trinuclear complex.

Science.gov (United States)

Bhunia, Asamanjoy; Gamer, Michael T; Ungur, Liviu; Chibotaru, Liviu F; Powell, Annie K; Lan, Yanhua; Roesky, Peter W; Menges, Fabian; Riehn, Christoph; Niedner-Schatteburg, Gereon

2012-09-17

The Schiff base compound 2,2'-{[(2-aminoethyl)imino]bis[2,1-ethanediyl-nitriloethylidyne]}bis-2-hydroxy-benzoic acid (H(4)L) as a proligand was prepared in situ. This proligand has three potential coordination pockets which make it possible to accommodate from one to three metal ions allowing for the possible formation of mono-, di-, and trinuclear complexes. Reaction of in situ prepared H(4)L with Dy(NO(3))(3)·5H(2)O resulted in the formation of a mononuclear complex [Dy(H(3)L)(2)](NO(3))·(EtOH)·8(H(2)O) (1), which shows SMM behavior. In contrast, reaction of in situ prepared H(4)L with Mn(ClO(4))(2)·6H(2)O and Dy(NO(3))(3)·5H(2)O in the presence of a base resulted in a trinuclear mixed 3d-4f complex (NHEt(3))(2)[Dy{Mn(L)}(2)](ClO(4))·2(H(2)O) (2). At low temperatures, compound 2 is a weak ferromagnet. Thus, the SMM behavior of compound 1 can be switched off by incorporating two Mn(II) ions in close proximity either side of the Dy(III). This quenching behavior is ascribed to the presence of the weak ferromagnetic interactions between the Mn(II) and Dy(III) ions, which at T > 2 K act as a fluctuating field causing the reversal of magnetization on the dysprosium ion. Mass spectrometric ion signals related to compounds 1 and 2 were both detected in positive and negative ion modes via electrospray ionization mass spectrometry. Hydrogen/deuterium exchange (HDX) reactions with ND(3) were performed in a FT-ICR Penning-trap mass spectrometer.

Study of the structure of the transition nuclei 152Dy, 154Dy and 156Er at high angular momentum

International Nuclear Information System (INIS)

Azgui, F.

1985-01-01

Measurements of feeding times of high spin yrast states in 152 Dy, 154 Dy and 156 Er were utilized to obtain information about possible spin dependent shape changes. Feeding times as well as lifetimes were determined with the recoil distance technique. In 152 Dy only long feeding times (> 10 ps) could be identified, indicating that the aligned-particle yrast states are fed through configuration of similar character, with little direct population from collective cascade in the continuum region. In 154 Dy discrete states with I ≤ 30 have lifetimes which are characteristically collective, whereas the preyrast cascade exhibit both fast ( 10 ps) feeding components. The latter imply a change with increasing spin from collective to aligned-particle character, signalling a prolate to oblate shape transition. In 156 Er the yrast states up to spin 20 ℎ were found to be collective. These levels are fed, however, from long-lived high spin states, causing time delay up to ∼ 100 ps, the existence of which is interpreted as a signature for an oblate shape at high spin [fr

Modification of magnetoresistance and magnetic properties of Ni thin films by adding Dy interlayer

Science.gov (United States)

Vorobiov, S. I.; Shabelnyk, T. M.; Shutylieva, O. V.; Pazukha, I. M.; Chornous, A. M.

2018-03-01

The paper reports the influence of dysprosium (Dy) interlayer addition on structure, magnetoresistance and magnetic properties of nickel (Ni) thin films. Trilayer film systems Ni/Dy/Ni have been prepared by alternate electron-beam evaporation. It is demonstrated that all as-prepared and annealed Ni thin films have face-centered cubic structure. The composition of the samples after addition of the Dy interlayer corresponds to the combination of face-centered cubic (Ni) and hexagonal close-packed (Dy) structures. The structure of Ni/Dy/Ni film systems changes from amorphous to polycrystalline when Dy interlayer thickness (t Dy) is more than 15 nm. The value of magnetoresistance increases with the adding the Dy interlayer in both longitudinal and transverse geometries, meanwhile the anisotropic character of magnetoresistance field dependences retained. The saturation and reversal magnetizations are reduced with the increasing of the Dy thickness interlayer, while the coercivity takes the minimum value at t Dy = 15 nm. The following increasing of t Dy leads to increasing of coercivity near to three times. This result indicates the influence of the crystal structure on the magnetic properties of Ni thin films at adding Dy interlayer.

Mixed phosphates of the Na3PO4 - LnPO4 systems

International Nuclear Information System (INIS)

Slivko, T.A.; Smirnova, I.N.; Zimina, G.V.; Spiridonov, F.M.; Chudinova, N.N.

2002-01-01

The phase relationships in the systems Na 3 PO 4 - LnPO 4 (subsolidus 950 Deg C cross-sections), where Ln=Sm, Eu, Tb, Dy, Ho, Tm, Yb, Lu, were studied by X-ray analysis. Reactions of the components were deduced, formed phases were separated and identified. The Na 6 Ln 3 (PO 4 ) 5 (Ln=Dy, Ho, Tm), Na 3 Ln 2 (PO 4 ) 3 (Ln=Tm, Yb, Lu) compounds and phases of the unstable composition Na 6+x Ln 3-x/3 (PO 4 ) 5 (Ln=Yb, Lu, 0 ≤ x ≤ 1.5) were detected for the first time. In all systems the existence of the Na 3-x Ln x/3 PO 4 unstable composition phase on the basis of the high temperature modification of sodium phosphate (sp. gr. Fm3m) is established, suggesting that stabilization of this modification by rare earth ions is possible [ru

High-spin structure of neutron-rich Dy isotopes

Indian Academy of Sciences (India)

Neutron-rich Dy isotopes; high-spin states; g-factors; cranked HFB theory. ... for 164Dy marking a clear separation in the behaviour as a function of neutron ... cipal x-axis as the cranking axis) in this mass region we have planned to make a sys-.

Mechanical and corrosion properties of binary Mg–Dy alloys for medical applications

International Nuclear Information System (INIS)

Yang Lei; Huang Yuanding; Peng Qiuming; Feyerabend, Frank; Kainer, Karl Ulrich; Willumeit, Regine; Hort, Norbert

2011-01-01

Microstructure, mechanical and corrosion properties of binary magnesium–dysprosium (Mg-5, 10, 15, 20 wt.% Dy) alloys were investigated for medical applications. In the as-cast condition, the distribution of Dy is quite inhomogeneous. Mg–10Dy alloy exhibits a moderate tensile and compression yield strength, and the best elongation and corrosion resistance. After T4 (solutionizing) treatment, the distribution of Dy becomes homogeneous. The tensile and compression yield strength of all Mg–Dy alloys decreases. The elongation remains unchanged, while the corrosion resistance is largely improved after T4 treatment.

Mechanical and corrosion properties of binary Mg-Dy alloys for medical applications

Energy Technology Data Exchange (ETDEWEB)

Yang Lei, E-mail: lei.yang@hzg.de [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, D-21502 Geesthacht (Germany); Yuanding, Huang; Qiuming, Peng; Feyerabend, Frank; Kainer, Karl Ulrich; Willumeit, Regine; Hort, Norbert [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Max-Planck-Str. 1, D-21502 Geesthacht (Germany)

2011-12-15

Microstructure, mechanical and corrosion properties of binary magnesium-dysprosium (Mg-5, 10, 15, 20 wt.% Dy) alloys were investigated for medical applications. In the as-cast condition, the distribution of Dy is quite inhomogeneous. Mg-10Dy alloy exhibits a moderate tensile and compression yield strength, and the best elongation and corrosion resistance. After T4 (solutionizing) treatment, the distribution of Dy becomes homogeneous. The tensile and compression yield strength of all Mg-Dy alloys decreases. The elongation remains unchanged, while the corrosion resistance is largely improved after T4 treatment.

Co-precipitation synthesis of YAG:Dy nanophosphor and its thermometric properties

International Nuclear Information System (INIS)

Chong, Joo-Yun; Zhang, Yuelan; Wagner, Brent K.; Kang, Zhitao

2013-01-01

Highlights: •YAG:Dy nanophosphors were synthesized with particle size of about 50 nm. •Optimized doping concentration of 6%Dy was determined. •Thermometric photoluminescence properties were studied between 20 and 350 °C. •Temperature-sensitive change in peak ratio of 496/457 nm emissions was demonstrated. •Suitable for potential thermographic applications when dispersed in a liquid media. -- Abstract: Dy 3+ doped yttrium aluminum garnet (YAG) nanophosphors were synthesized by a co-precipitation method for potential thermographic applications in a liquid media dispersed with fluorescent nanoparticles. The doping concentration and annealing temperature on the structural and optical properties of YAG:Dy were investigated. Pure phase YAG:Dy nanophosphors were obtained by annealing the co-precipitated hydroxide products at above 900 °C. Maximum photoluminescence intensity was observed from 6%Dy doped YAG samples. The effect of measuring temperature between 20 and 350 °C on the photoluminescence spectra of nano YAG:Dy was investigated. A temperature-sensitive change in the peak intensity ratio of 496/457 nm emission lines was demonstrated for such nanophosphors for the first time, suggesting potential applications in temperature monitoring of fuel spray

Co-precipitation synthesis of YAG:Dy nanophosphor and its thermometric properties

Energy Technology Data Exchange (ETDEWEB)

Chong, Joo-Yun [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Zhang, Yuelan [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Wagner, Brent K. [Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Kang, Zhitao, E-mail: zhitao.kang@gtri.gatech.edu [Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, GA 30332 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2013-12-25

Highlights: •YAG:Dy nanophosphors were synthesized with particle size of about 50 nm. •Optimized doping concentration of 6%Dy was determined. •Thermometric photoluminescence properties were studied between 20 and 350 °C. •Temperature-sensitive change in peak ratio of 496/457 nm emissions was demonstrated. •Suitable for potential thermographic applications when dispersed in a liquid media. -- Abstract: Dy{sup 3+} doped yttrium aluminum garnet (YAG) nanophosphors were synthesized by a co-precipitation method for potential thermographic applications in a liquid media dispersed with fluorescent nanoparticles. The doping concentration and annealing temperature on the structural and optical properties of YAG:Dy were investigated. Pure phase YAG:Dy nanophosphors were obtained by annealing the co-precipitated hydroxide products at above 900 °C. Maximum photoluminescence intensity was observed from 6%Dy doped YAG samples. The effect of measuring temperature between 20 and 350 °C on the photoluminescence spectra of nano YAG:Dy was investigated. A temperature-sensitive change in the peak intensity ratio of 496/457 nm emission lines was demonstrated for such nanophosphors for the first time, suggesting potential applications in temperature monitoring of fuel spray.

Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson ...

Indian Academy of Sciences (India)

We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tan and A. We observe that at fixed ...

New AMS method to measure the atom ratio {sup 146}Sm/{sup 147}Sm for a half-life determination of {sup 146}Sm

Energy Technology Data Exchange (ETDEWEB)

Kinoshita, N. [Tandem Accelerator Complex, Research Facility Center for Science and Technology, University of Tsukuba (Japan); Paul, M., E-mail: paul@vms.huji.ac.il [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Alcorta, M. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Bowers, M.; Collon, P. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556-5670 (United States); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 46624 (United States); DiGiovine, B. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Goriely, S. [Universite Libre de Bruxelles, CP-226, Brussels 1050 (Belgium); Greene, J.P.; Henderson, D.J.; Jiang, C.L. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Kashiv, Y. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556-5670 (United States); Kay, B.P.; Lee, H.Y.; Marley, S.T. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Nakanishi, T. [Faculty of Chemistry, Institute of Science and Engineering, Kanazawa University (Japan); Pardo, R.C.; Patel, N.; Rehm, K.E. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Robertson, D. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556-5670 (United States); and others

2013-01-15

The extinct p-process nuclide {sup 146}Sm (t{sub 1/2} = 103 {+-} 5 Myr) is known to have been present in the Early-Solar System and has been proposed as an astrophysical chronometer. {sup 146}Sm is also intensely used to date meteorite and planetary differentiation processes, enhancing the importance of an accurate knowledge of the {sup 146}Sm half-life. We are engaged in a new determination of the {sup 146}Sm half-life in which the {sup 146}Sm/{sup 147}Sm atom ratio is determined by accelerator mass spectrometry at the ATLAS facility of Argonne National Laboratory. In order to reduce systematic errors in the AMS determination of the {sup 146}Sm/{sup 147}Sm ratios (in the range of 10{sup -7}-10{sup -9}), {sup 146}Sm and {sup 147}Sm ions were alternately counted in the same detector in the focal plane of a gas-filled magnet, respectively in continuous-wave and attenuated mode. Quantitative attenuation is obtained with the 12 MHz pulsed and ns-bunched ATLAS beam by chopping beam pulses with an RF sweeper in a ratio (digitally determined) down to 1:10{sup 6}. The experiments and preliminary results are discussed.

Search for excited superdeformed bands in {sup 151}Dy

Energy Technology Data Exchange (ETDEWEB)

Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

1995-08-01

Following the first report of superdeformed (SD) bands with identical transition energies in the pairs ({sup 151}Tb*,{sup 152}Dy), ({sup 150}Gd*, {sup 151}Tb) and ({sup 153}Dy*, {sup 152}Dy) (where * denotes an excited SD band), it was proposed by Nazarewicz et al. that the observations could be understood in a strong-coupling approach if pseudo SU(3) symmetry were invoked. In this model there are three limiting values of the decoupling parameter; i.e. a = 0, {plus_minus}1. In the first two cases mentioned above the pairs of bands have nearly identical transition energies and are interpreted as proton excitations involving the [200]1/2 pseudospin orbital coupled to the {sup 152}Dy core, for which the value of the decoupling parameter is calculated to be a =+1.

Effect of Dy additions on microstructure and magnetic properties of Fe-Nd-B magnets

International Nuclear Information System (INIS)

Ramesh, R.; Thomas, G.; Ma, B.M.

1987-05-01

It is shown that increasing additions of Dy causes the remanence B/sub r/ to decrease linearly. The intrinsic coercivity, iHc, increases sharply for small additions of Dy, but the increase is not proportional for higher Dy contents. The iHc increases almost linearly with the effective anisotropy field of the RE 2 Fe 14 B phase until the Dy content is about 10% of the total rare earth content. Above this concentration, there is strong deviation from linearity. Various types of possible concentration profiles of the substituted rare earth are suggested. It is also argued that preferential segregation of Dy to the interfaces could be beneficial in increasing the nucleation field. Morphologically there is no apparent effect of Dy on the microstructure. However, in the 5 atomic % Dy sample, Dy rich oxides were observed. It is shown through Energy Dispersive Xray Spectroscopy (EDXS) line profiling that Dy partitions preferentially into the RE 2 Fe 14 B phase in all the cases. No segregation of Dy to the interphase interfaces has been detected

Archaeometric investigation of medieval Bulgarian glasses and sgraffito ceramics by neutron activation analysis

International Nuclear Information System (INIS)

Dzhingova, R.; Kulev, I.

1985-01-01

Instrumental neutron activation analysis was used to determine the content of Au, Ba, Ca, Ce, Cl, Cr, Co, Cs, Cu, Eu, Fe, Hf, La, Lu, Mn, Na, Rb, Sc, Sm, Sr, Ta, Tb, Th, Ti, U, Sb, V and Yb in glass samples excavated from medieval glassworkshops in Pliska and Preslav and in 20 glass finds from Preslav. Sgraffito ceramic samples excavated in Veliko Tarnovo were also analysed and the elements Al, As, Au, Ba, Br, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Si, Sm, Ta, Tb, Th, Ti, U, V and Yb were determined. In order to localize the production site of the archaeological finds, the results from the analysis were subjected to cluster analysis, and stepwise discriminant analysis using the program package BMDP. A variety of the production of the medieval glass workshop in Preslav was identified and evaluated. It was proved that a part of the sgraffito ceramics samples have been produced in one and the same place and that the chemical composition might be successfully used to differentiate between the production of two workshops

Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

Science.gov (United States)

Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

2015-01-01

A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln2(phen)2(SO4)3(H2O)2]n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO4 2 - anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic-inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.

Determination of '14 MeV' cross sections for (n,p)-, (n,α)-, (n,2n)-, and (n,np + pn + d)-reactions on the elements Sc, Ni, Ge, Pd, Cd, Sm, Dy, Gd, and Yb in consideration of the 'effective' n-energy spectra

International Nuclear Information System (INIS)

Weigel, H.; Michel, R.; Herr, W.

1975-01-01

A total of 24 cross sections was determined for (n,p)-, (n,α)-, (n,2n)-, and (n,np + pn + d)-reactions of fast (so called '14 MeV') neutrons on the elements Sc, Ni, Ge, Pd, Cd, Sm, Dy, Gd, and Yb. 58 Ni(n,p) 58 Co served as monitor reaction. It is a special feature of this work that calculated neutron energy spectra for the '14 MeV' n-tube (Type Philips 18602) were considered, thus enabling us to supply each individual sigma-value with the respective n-energy distribution. On the basis of an extensive literature search (up to the beginning of 1973) the sigma-data were compared with experimental results of other authors and with those deduced from the statistical model. For some nuclides (e.g. 58 Ni, 154 Gd, 168 Yb, 176 Yb) it was possible to show the limits of applicability of the latter model. Summarizing, 12 cross sections and 3 isomeric ratios, nearly all of which belong to reaction products with rather long half-lifes, were determined for the first time. (orig.) [de

DyNi2Mn—magnetisation and Mössbauer spectroscopy

International Nuclear Information System (INIS)

Wang Jianli; Campbell, Stewart James; Kennedy, Shane Joseph; Dou Shixue; Wu Guangheng

2012-01-01

The physical properties of DyNi 2 Mn doped with 57 Fe have been investigated by X-ray diffraction, magnetisation (10–300 K) and 57 Fe Mössbauer spectroscopy measurements (5–300 K). DyNi 2 Mn( 57 Fe) crystallizes in the MgCu 2 -type cubic structure (Fd   −3m space group). The ordering temperature is found to be T C  = 99(2) K, much higher than those of DyNi 2 (∼22 K) and DyMn 2 (∼35 K). Analyses of isothermal M–H curves and the related Arrott plots confirm that the magnetic phase transition at T C is second order. The magnetic entropy change around T C is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The spectra above T C exhibit features consistent with quadrupolar effects while below T C the spectra exhibit magnetic hyperfine splitting. The Debye temperature for DyNi 2 Mn has been determined as θ D  = 200(20) K from a fit to the variable temperature isomer shift IS(T).

DyNi{sub 2}Mn-magnetisation and Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Wang Jianli; Campbell, Stewart James, E-mail: stewart.campbell@adfa.edu.au [University of New South Wales, School of Physical, Environmental and Mathematical Sciences (Australia); Kennedy, Shane Joseph [ANSTO, Bragg Institute (Australia); Dou Shixue [University of Wollongong, Institute for Superconductivity and Electronic Materials (Australia); Wu Guangheng [Chinese Academy of Science, Institute of Physics (China)

2012-03-15

The physical properties of DyNi{sub 2}Mn doped with {sup 57}Fe have been investigated by X-ray diffraction, magnetisation (10-300 K) and {sup 57}Fe Moessbauer spectroscopy measurements (5-300 K). DyNi{sub 2}Mn({sup 57}Fe) crystallizes in the MgCu{sub 2}-type cubic structure (Fd{sup }-3m space group). The ordering temperature is found to be T{sub C} = 99(2) K, much higher than those of DyNi{sub 2} ({approx}22 K) and DyMn{sub 2} ({approx}35 K). Analyses of isothermal M-H curves and the related Arrott plots confirm that the magnetic phase transition at T{sub C} is second order. The magnetic entropy change around T{sub C} is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The spectra above T{sub C} exhibit features consistent with quadrupolar effects while below T{sub C} the spectra exhibit magnetic hyperfine splitting. The Debye temperature for DyNi{sub 2}Mn has been determined as {theta}{sub D} = 200(20) K from a fit to the variable temperature isomer shift IS(T).

24/7 SM slavery.

Science.gov (United States)

Dancer, Peter L; Kleinplatz, Peggy J; Moser, Charles

2006-01-01

This study describes the nature of 24/7 SM slavery as practiced within the SM (sadomasochistic) community. These SM participants, who attempt to live full-time in owner-slave roles, represent a small proportion of those with SM interests. SM slaves have not been studied systematically to determine if and how they differ from other SM practitioners. An online questionnaire was used to obtain responses from individuals who self-identified as slaves. A total of 146 respondents participated, 53% female and 47% male, ranging in age from 18 to 72. We explored the depth of their relationships, how well they approximated "slavery," and how their relationships were structured to maintain distinct roles. Data showed that in long-term SM slave relationships, a power differential exists which extends beyond time-limited SM or sexual interactions. Owners and slaves often use common, daily life experiences or situations, such as the completion of household chores, money management, and morning or evening routines, to distinguish and maintain their respective roles. In addition, contrary to the perception of total submission, results revealed that slaves exercise free will when it is in their best interests to do so. These relationships were long-lasting and satisfying to the respondents.

Neutron detection using Dy2O3 activation detectors

International Nuclear Information System (INIS)

Gomaa, M.A.; Mohamed, E.J.

1979-01-01

The aim of the present study is to examine the usefulness of Dy 2 O 3 not only as thermal neutron activation detector but also as a fast neutron detector. For thermal neutrons, the half life of 165 Dy is measured to be (141 +- 6) min, its response to thermal neutrons is (2.18 +- 0.01) cpm/ncm -2 s -1 for a 250 mg Dy 2 O 3 pellet. For fast neutrons the Dy 2 O 3 detector is placed within a 20 cm polyethylene sphere and its response is found to be (2.2 +- 0.1) cpm/ncm -2 s -1 for 4 MeV neutrons and (2.10 +- 0.04) cpm/ncm -2 s -1 for 14 MeV neutrons. For neutron dosimetry, its response is found to be (16.7 +- 0.4) cpm per mrem h -1 . (author)

SYNTHESIS, SPECTROSCOPIC CHARACTERIZATION AND ...

African Journals Online (AJOL)

userpc

ABSTRACT. A tridendatate Schiff base,L, 2-((2-hydroxynaphthalen-1-yl) methyleneamino)benzoic acid was prepared by condensation of 2-aminobenzoic acid with 2-hydroxy-1-naphthaldehyde.The prepared ligand was used to synthesize Sm(III) and Dy(III) complexes [LnL(NO3)2]NO3.2H2O,. (Ln=Sm(III) and Dy(III)).

Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider

International Nuclear Information System (INIS)

Singhal, Jai Kumar; Singh, Sardar; Nagawat, Ashok K.

2007-01-01

We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tanβ and m A . We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson. (author)

Study of the nuclear structure of 155Eu

International Nuclear Information System (INIS)

Genezini, Frederico Antonio

2004-01-01

The 155 Eu nuclide was investigated by the directional angular correlation technique following the β decay of 155 Sm. The angular correlation measurements were carried out using a setup with 4 Ge detectors and a multi parametric data acquisition system. To perform the data analysis a new methodology was developed . The multipole mixing ratios of twenty sixty γ- transitions were determined. Seven of them agreed with the results of earlier angular correlation studies and nineteen obtained for the first time confirmed the multipolarity suggested in earlier electron capture studies. Besides, the spin of the level at 1106.83 keV as well as the parity of the level at 1301.41 keV have also been suggested. The nuclear structure of 155 Eu was discussed successfully in terms of the single particle model using a deformed Woods-Saxon potential plus residual pairing interaction permitting the description of the rotational quasi-proton band heads. (author)

Surface activation of dyed fabric for cellulase treatment.

Science.gov (United States)

Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

2011-10-01

Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Studies of normal deformation in {sup 151}Dy

Energy Technology Data Exchange (ETDEWEB)

Nisius, D.; Janssens, R.V.F.; Crowell, B. [and others

1995-08-01

The wealth of data collected in the study of superdeformation in {sup 151}Dy allowed for new information to be obtained on the normally deformed structures in this nucleus. At high spin several new yrast states have been identified for the first time. They were associated with single-particle excitations. Surprisingly, a sequence was identified with energy spacings characteristic of a rotational band of normal ({beta}2 {approximately} 0.2) deformation. The bandhead spin appears to be 15/2{sup -} and the levels extend up to a spin of 87/2{sup -}. A clear backbend is present at intermediate spins. While a similar band based on a bandhead of 6{sup +} is known in {sup 152}Dy, calculations suggest that this collective prolate band should not be seen in {sup 151}Dy. In the experiment described earlier in this report that is aimed at determining the deformations associated with the SD bands in this nucleus and {sup 152}Dy, the deformation associated with this band will be determined. This will provide further insight into the origin of this band.

Metamagnetism, sign reversal and low temperature magnetocaloric effect in single-crystalline EuV2Al20

Science.gov (United States)

Ramesh Kumar, K.; Nair, Harikrishnan S.; Bhattacharyya, A.; Thamizhavel, A.; Strydom, André M.

2018-04-01

The Frank-Kasper cage compound EuV2Al20 crystallizes in the cubic structure with Fd 3 ‾ m space group and exhibits unusual magnetic and transport properties. The system undergoes an antiferromagnetic transition below 5.6 K wherein the Eu2+ moments are aligned anti-parallel along 〈1 1 1〉 direction and the system exhibits a weak metamagetic transition at the field of 1 T. Arrott plots (M2 vs H / M) show a "S" shaped variation in the low fields below TN and the plausible reason for the occurrence of negative slope is discussed. Isothermal magnetic entropy change is estimated from both magnetization and heat capacity measurements invoking the Maxwell's thermodynamic relations. Temperature variation of ΔSm showed a weak negative minimum and a sign reversal at the field value of 1 T due to field induced metamagnetic transition. Universal master curve is constructed by rescaling the ΔSm vs T curves in the context of analysing the nature of the magnetic transition.

Luminescent, magnetic and ferroelectric properties of noncentrosymmetric chain-like complexes composed of nine-coordinate lanthanide ions.

Science.gov (United States)

Li, Xi-Li; Chen, Chun-Lai; Xiao, Hong-Ping; Wang, Ai-Ling; Liu, Cai-Ming; Zheng, Xianjun; Gao, Li-Jun; Yang, Xiao-Gang; Fang, Shao-Ming

2013-11-21

Reaction of the chiral ligand (-)-4,5-pinenepyridyl-2-pyrazine (L) with Ln(hfac)3·2H2O precursors [hfac(-) = 1,1,1,5,5,5-hexafluoroacetylacetonate, Ln = Sm(3+) (1), Eu(3+) (2), Tb(3+) (3) and Dy(3+) (4)] in methanol solution led to the formation of four noncentrosymmetric lanthanide complexes with the general formula [Ln(hfac)3L]n·H2O. The single-crystal X-ray diffraction analyses revealed that they are isostructural and take a one-dimensional (1D) chain structure based on the Ln(hfac)3L repeating units, in which the nine-coordinate Ln(3+) ions reside in a tricapped trigonal prism (TTP) environment never reported in previous 1D chain lanthanide complexes. The investigations of their photophysical properties showed that complexes 1, and 3 exhibit characteristic emissions of Sm(3+), Eu(3+) and Tb(3+) ions with respective luminescent lifetime values of 0.065, 1.066 and 0.129 ms, while complex 4 does not display any emission. The different luminescent intensities and lifetimes among them were further discussed in detail. Moreover, the magnetic properties of complexes 1-4 were assessed with a special emphasis on the Dy(3+) complex 4. Alternating-current (ac) magnetic susceptibility measurements indicated that field-induced two-step slow magnetic relaxation processes were observed in 4, indicating the single-molecule magnet (SMM) behavior of 4. In addition, the noncentrosymmetric complexes 1-4 crystallizing in the same polar point group (Cs) exhibit both ferroelectric and nonlinear optical properties at room temperature. All these features make them multifunctional crystalline molecule materials.

Application and evaluation of the mass spectrometric isotope dilution technique in the determination of rare earths in geological materials

International Nuclear Information System (INIS)

Moraes, N.M.P. de.

1988-01-01

Establishment of the experimental procedures employed in the rare earth element determination of geological samples by mass spectrometric isotope dilution analysis is discussed in the present work. The procedures involve preparation and calibration of the isotope tracers isotope dilution, dissolution in a teflon pressure vessel, chemical separation and isotope analysis using a fully automated Micromass VG ISOTOPES model 354 thermal ionization mass spectrometer. For the initial chemical separation of total rare earths the cationic resin was employed and HC1 and HNO 3 acids as eluents. In the second step rare earths elements were separated into individual (La, Ce and Nd) and subgroups (Sm-Eu-Gd, Yb-Er-Dy) fractions using the same cationic resin and α-HIBA as eluent. Nine elements La, Ce, Nd, Sm, Eu, Gd, Dy, Er and Yb are determined by this method in the ''United States Geological Survey'' (USGS) standard samples GSP-1, AGV-1 and G-2, with an overall precision of +- 1 to 2% and an accuracy of 5%. The concentration of rare earth element determined in the standard sample PCC-1 showed that the total analytical blanks are in submicrogram levels. The concentration of rare earth elements in the same USGS standard samples were also determined by Instrumental neutron activation analysis, neutron activation analysis with chemical separation before irradiation and inductively coupled argon plasma spectroscopy. The chemical procedures employed for these methods are the same as that used for mass spectrometric isotope dilution. Based on the results obtained, each method was evaluated pointing out their merits and defects. The study clearly showed that the chemical procedure employed for all these techniques was satisfactory. (author) [pt

Enhanced ultraviolet photo-response in Dy doped ZnO thin film

Science.gov (United States)

Kumar, Pawan; Singh, Ranveer; Pandey, Praveen C.

2018-02-01

In the present work, a Dy doped ZnO thin film deposited by the spin coating method has been studied for its potential application in a ZnO based UV detector. The investigations on the structural property and surface morphology of the thin film ensure that the prepared samples are crystalline and exhibit a hexagonal crystal structure of ZnO. A small change in crystallite size has been observed due to Dy doping in ZnO. AFM analysis ascertains the grain growth and smooth surface of the thin films. The Dy doped ZnO thin film exhibits a significant enhancement in UV region absorption as compared to the pure ZnO thin film, which suggests that Dy doped ZnO can be used as a UV detector. Under UV irradiation of wavelength 325 nm, the photocurrent value of Dy doped ZnO is 105.54 μA at 4.5 V, which is 31 times greater than that of the un-doped ZnO thin film (3.39 μA). The calculated value of responsivity is found to increase significantly due to the incorporation of Dy in the ZnO lattice. The observed higher value of photocurrent and responsivity could be attributed to the substitution of Dy in the ZnO lattice, which enhances the conductivity, electron mobility, and defects in ZnO and benefits the UV sensing property.

Understanding the nitrate coordination to Eu3+ ions in solution by potential of mean force calculations

International Nuclear Information System (INIS)

Duvail, M.; Guilbaud, Ph.

2011-01-01

Coordination of nitrate anions with lanthanoid cations (Ln 3+ ) in water, methanol and octanol-1 has been studied by means of molecular dynamics simulations with explicit polarization. Potential of mean force (PMF) profiles have been calculated for a mono-complex of lanthanoid nitrate (Ln(NO 3 ) 2+ ) in these solvents using umbrella-sampling molecular dynamics. In pure water, no difference in the nitrato coordination to lanthanoids (Nd 3+ , Eu 3+ and Dy 3+ ) is observed, i.e. the nitrate anion prefers the monodentate coordination, which promotes the salt dissociation. Then, the influence of the nature of the solvating molecules on the nitrato coordination to Eu 3+ has been investigated. PMF profiles point out that both monodentate and bidentate coordinations are stable in neat methanol, while in neat octanol, only the bidentate one is. MD simulations of Eu(NO 3 ) 3 in water-octanol mixtures with different concentrations of water have been then performed and confirm the importance of the water molecules' presence on the nitrate ion's coordination mode. (authors)

Sonochemical synthesis of Dy-doped ZnO nanostructures and their photocatalytic properties

Energy Technology Data Exchange (ETDEWEB)

Yayapao, Oranuch [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun, E-mail: ttpthongtem@yahoo.com [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Phuruangrat, Anukorn, E-mail: phuruangrat@hotmail.com [Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thongtem, Somchai [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-11-05

Highlights: •Undoped and Dy-doped ZnO used as photocatalysts. •They were synthesized by sonochemistry. •The promising materials for treatment of organic pollutants. -- Abstract: Dy-doped ZnO nanostructures were synthesized by a sonochemical method. The concentration effect of Dy on their phase, morphology, optical properties and photocatalytic activities was investigated. XRD patterns indicated that the as-synthesized 0–3% Dy-doped ZnO was hexagonal wurtzite structure. SEM and TEM show that the products were nanorods with their growth direction along the c axis. The photoluminescence spectrum of 3% Dy-doped ZnO, applied by Gaussian analysis, consists of three emission peaks at 376 nm, 448 nm and 487 nm. The photocatalytic activities of the as-synthesized products were determined from the degradation of methylene blue (C{sub 16}H{sub 18}N{sub 3}SCl) by UV radiation. In this research, the 3% Dy-doped ZnO showed the highest photocatalytic activity.

Sonochemical synthesis of Dy-doped ZnO nanostructures and their photocatalytic properties

International Nuclear Information System (INIS)

Yayapao, Oranuch; Thongtem, Titipun; Phuruangrat, Anukorn; Thongtem, Somchai

2013-01-01

Highlights: •Undoped and Dy-doped ZnO used as photocatalysts. •They were synthesized by sonochemistry. •The promising materials for treatment of organic pollutants. -- Abstract: Dy-doped ZnO nanostructures were synthesized by a sonochemical method. The concentration effect of Dy on their phase, morphology, optical properties and photocatalytic activities was investigated. XRD patterns indicated that the as-synthesized 0–3% Dy-doped ZnO was hexagonal wurtzite structure. SEM and TEM show that the products were nanorods with their growth direction along the c axis. The photoluminescence spectrum of 3% Dy-doped ZnO, applied by Gaussian analysis, consists of three emission peaks at 376 nm, 448 nm and 487 nm. The photocatalytic activities of the as-synthesized products were determined from the degradation of methylene blue (C 16 H 18 N 3 SCl) by UV radiation. In this research, the 3% Dy-doped ZnO showed the highest photocatalytic activity

Determinación del coeficiente piroeléctrico del sistema ferroeléctrico cerámico de Pb0.88Ln0.08Ti0.98Mn0.02O3 (Ln=La, Sm, Eu y su aplicación en detectores de infrarrojo

Directory of Open Access Journals (Sweden)

Suaste-Gómez, E.

2004-12-01

Full Text Available In this work the dielectric and pyroelectric characteristics of the ferroelectric ceramic system of Pb0.88(Ln0.08Ti0.98Mn0.02O3 (Ln = La, Sm, Eu are studied in order to determine its usefulness as infrared dectectors. Dielectric constant and pyroelectric coefficient of the ceramics were determined. This material with perovskite structure presented a phase transition from tetragonal to cubic on the heating process, besides of presenting high values of dielectric constant. Values of figure of merit for infrared detection Rv=pi/εr were calculated. The results were compared with other materials used as infrared detectors.En este trabajo se estudian las características dieléctricas y piroeléctricas del sistema ferroléctrico cerámico de Pb0.88(Ln0.08Ti0.98 Mn0.02O3 (Ln = La, Sm, Eu para determinar su utilidad como detectores de infrarrojo. Se determinó la constante dieléctrica y el coeficiente piroeléctrico de las cerámicas. Este material con estructura de perovskita presentó una transición de fase tetragonal a cúbica en el proceso de calentamiento, además de presentar altos valores de la constante dieléctrica. Se obtuvieron valores de la figura de mérito para detección infrarroja Rv=pi/εr Los resultados se compararon con otros materiales usados como detectores de infrarrojo.

Calorimetric investigation on the Pb-Sm and Sn-Sm alloys

International Nuclear Information System (INIS)

Berrada, A.-E.-A.; Claire, Y.; Chafik el Idrissi, M.; Castanet, R.

1997-01-01

The integral enthalpy of formation of the Sm-Pb and Sm-Sn melts at 1203 K, h f , was determined by direct reaction calorimetry (drop method) in the Pb and Sn rich sides with the help of a high-temperature Tian-Calvet calorimeter. The results can be fitted respectively with reference to the mole fraction of samarium, x, as follows: f /kJmol -1 =x(1-x)(-109.8 -372.0.7x) with 0 Sm f /kJmol -1 =x(1- x)(-277.0+105.4x) with 0 Sm -1 respectively. Such negative values suggest the existence of a strong short-range order in the liquid state. The stoichiometry and the thermal stability of these associations needs additional thermodynamic determinations concerning mainly the free enthalpy of formation. It will be determined by Knudsen-effusion combined with mass spetrometry in a further work. (orig.)

Determination of Rare Earth Elements in Geological Samples Using Laser-Induced Breakdown Spectroscopy (LIBS).

Science.gov (United States)

Bhatt, Chet R; Jain, Jinesh C; Goueguel, Christian L; McIntyre, Dustin L; Singh, Jagdish P

2018-01-01

Laser-induced breakdown spectroscopy (LIBS) was used to detect rare earth elements (REEs) in natural geological samples. Low and high intensity emission lines of Ce, La, Nd, Y, Pr, Sm, Eu, Gd, and Dy were identified in the spectra recorded from the samples to claim the presence of these REEs. Multivariate analysis was executed by developing partial least squares regression (PLS-R) models for the quantification of Ce, La, and Nd. Analysis of unknown samples indicated that the prediction results of these samples were found comparable to those obtained by inductively coupled plasma mass spectrometry analysis. Data support that LIBS has potential to quantify REEs in geological minerals/ores.

Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores.

Science.gov (United States)

Malkin, B Z; Lummen, T T A; van Loosdrecht, P H M; Dhalenne, G; Zakirov, A R

2010-07-14

The experimental temperature dependence (T = 2-300 K) of single crystal bulk and site susceptibilities of rare earth titanate pyrochlores R(2)Ti(2)O(7) (R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) is analyzed in the framework of crystal field theory and a mean field approximation. Analytical expressions for the site and bulk susceptibilities of the pyrochlore lattice are derived taking into account long range dipole-dipole interactions and anisotropic exchange interactions between the nearest neighbor rare earth ions. The sets of crystal field parameters and anisotropic exchange coupling constants have been determined and their variations along the lanthanide series are discussed.

Nuclear Data Sheets for A=158

Energy Technology Data Exchange (ETDEWEB)

Nica, N. [Cyclotron Institute, Texas A& M University, College Station, TX 77843-3366 (United States); On leave from the National Institute for Physics and Nuclear Engineering “Horia Hulubei”, Bucharest (Romania); Under Subcontract No. 100586 with National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2017-03-15

The experimental results published before February 2017 from the various reaction and decay studies leading to nuclides {sup 158}Nd, {sup 158}Pm, {sup 158}Sm, {sup 158}Eu, {sup 158}Gd, {sup 158}Tb, {sup 158}Dy, {sup 158}Ho, {sup 158}Er, {sup 158}Tm, {sup 158}Yb, {sup 158}Lu, {sup 158}Hf, {sup 158}Ta, {sup 158}W in the A=158 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties. Large sections of the mass chain are almost identical to the ones in the previous 2004He05 NDS publication by R.G. Helmer.

Attenuation studies near K-absorption edges using Compton scattered 241Am gamma rays

International Nuclear Information System (INIS)

Abdullah, K.K.; Ramachandran, N.; Karunakaran Nair, K.; Babu, B.R.S.; Joseph, Antony; Thomas, Rajive; Varier, K.M.

2008-01-01

We have carried out photon attenuation measurements at several energies in the range from 49.38 keV to 57.96 keV around the K-absorption edges of the rare earth elements Sm, Eu, Gd, Tb, Dy and Er using 59.54 keV gamma rays from 241 Am source after Compton scattering from an aluminium target. Pellets of oxides of the rare earth elements were chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. The scattered gamma rays were detected by an HPGe detector. The results are consistent with theoretical values derived from the XCOM package. (author)

Search for neutrinoless double-electron capture of 156Dy

Science.gov (United States)

Finch, S. W.; Tornow, W.

2015-12-01

Background: Multiple large collaborations are currently searching for neutrinoless double-β decay, with the ultimate goal of differentiating the Majorana-Dirac nature of the neutrino. Purpose: Investigate the feasibility of resonant neutrinoless double-electron capture, an experimental alternative to neutrinoless double-β decay. Method: Two clover germanium detectors were operated underground in coincidence to search for the de-excitation γ rays of 156Gd following the neutrinoless double-electron capture of 156Dy. 231.95 d of data were collected at the Kimballton underground research facility with a 231.57 mg enriched 156Dy sample. Results: No counts were seen above background and half-life limits are set at O (1016-1018) yr for the various decay modes of 156Dy. Conclusion: Low background spectra were efficiently collected in the search for neutrinoless double-electron capture of 156Dy, although the low natural abundance and associated lack of large quantities of enriched samples hinders the experimental reach.

Evaluation of the exothermicity of the chemi-ionization reaction Sm + O → SmO+ + e−

International Nuclear Information System (INIS)

Cox, Richard M; Kim, JungSoo; Armentrout, P. B.; Bartlett, Joshua; VanGundy, Robert A.; Heaven, Michael C.; Ard, Shaun G.; Shuman, Nicholas S.; Viggiano, Albert A.; Melko, Joshua J.

2015-01-01

The exothermicity of the chemi-ionization reaction Sm + O → SmO + + e − has been re-evaluated through the combination of several experimental methods. The thermal reactivity (300–650 K) of Sm + and SmO + with a range of species measured using a selected ion flow tube-mass spectrometer apparatus is reported and provides limits for the bond strength of SmO + , 5.661 eV ≤ D 0 (Sm + -O) ≤ 6.500 eV. A more precise value is measured to be 5.72 5 ± 0.07 eV, bracketed by the observed reactivity of Sm + and SmO + with several species using a guided ion beam tandem mass spectrometer (GIBMS). Combined with the established Sm ionization energy (IE), this value indicates an exothermicity of the title reaction of 0.08 ± 0.07 eV, ∼0.2 eV smaller than previous determinations. In addition, the ionization energy of SmO has been measured by resonantly enhanced two-photon ionization and pulsed-field ionization zero kinetic energy photoelectron spectroscopy to be 5.7427 ± 0.0006 eV, significantly higher than the literature value. Combined with literature bond energies of SmO, this value indicates an exothermicity of the title reaction of 0.14 ± 0.17 eV, independent from and in agreement with the GIBMS result presented here. The evaluated thermochemistry also suggests that D 0 (SmO) = 5.83 ± 0.07 eV, consistent with but more precise than the literature values. Implications of these results for interpretation of chemical release experiments in the thermosphere are discussed

Magnetic Properties of Dy in Pb2Sr2DyCu3O8

International Nuclear Information System (INIS)

Skanthakumar, S.; Soderholm, L.; Movshovich, R.

1999-01-01

Superconductivity can be induced at high temperatures in Pb 2 Sr 2 RCu 3 O 8 (R - rare earth) by partially doping Ca 2+ for R 3+ . In order to understand the interplay between magnetism and superconductivity, the magnetic properties of the parent compounds, Pb 2 Sr 2 RCu 3 O 8 , have been studied. The work presented here includes magnetic susceptibility and specific heat measurements on R=Dy and extends the previous studies on R=Ce, Pr, Tb, Ho and Er. Specific heat experiments suggest that the Dy ions order antiferromagnetically with an ordering temperature of 1.3K. The magnetic susceptibility data are in good agreement with the susceptibility calculated using crystal field parameters that are extrapolated from previous modeling of the R=Er and Ho analogs of this series

Strategisch management (SM)

NARCIS (Netherlands)

Nagel, A.P.; Vercouteren, W.J.J.C.; Hoek, van der N.; Lohman, T.A.M.; Vermeulen, N.

1996-01-01

Kernbegrippen die bij de discussie van strategisch management (SM) aan de orde komen, zijn productinnovatie op ondernemingsniveau (oftewel strategische productinnovatie, SPI) en technologiestrategie. In dit artikel wordt een raamwerk van SM geintroduceerd. Daartoe worden de verschillende fasen van

Physical and optical properties of lithium borosilicate glasses doped with Dy3+ ions

Science.gov (United States)

Ramteke, D. D.; Gedam, R. S.; Swart, H. C.

2018-04-01

The borosilicate glasses with Dy3+ ions were prepared by the melt quench technique with varying concentration of Dy2O3. The glasses were characterized by the density calculation, absorbance and photoluminescence (PL) spectroscopy measurements. Density and molar volume of the glasses increases with increase in Dy3+ ions in the glass matrix. This behavior is correlated with the higher molecular weight and larger ionic radius of Dy3+ ion compared to the other constituents of glass matrix. Emission of Dy3+ doped glasses showed three bands at 482, 573 and at 665 nm which correspond to 6H15/2 (blue), 6H13/2 (yellow) and 6H11/2 (red) transitions. The emission spectra of glasses with different concentration of Dy3+ ions shows that, glasses with 0.5 mol% of Dy2O3 shows highest emission and decreases with further doping. CIE 1931 chromaticity diagram showed that the emission of these glasses was in the white region. Photographs of these glasses under 349 nm Light emitting diode excitation also confirmed the white light emission from these glasses.

Coercivity enhancement in Nd-Fe-B sintered permanent magnet by Dy nanoparticles doping

Energy Technology Data Exchange (ETDEWEB)

Liu, W.Q., E-mail: liuweiqiang77@hotmail.co [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Sun, H. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Yi, X.F. [Anhui Earth-panda Advance Magnetic Material Co., Ltd., Anhui 231500 (China); Liu, X.C.; Zhang, D.T. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Yue, M., E-mail: yueming@bjut.edu.c [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Zhang, J.X. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China)

2010-07-02

Nd-Fe-B permanent magnets with a small amount of Dysprosium (Dy) nanoparticles doping were prepared by conventional sintered method, and the microstructure and magnetic properties of the magnets were studied. Investigation shows that the coercivity rises gradually, while the remanence decreases simultaneously with increased Dy doping amount. As a result, the magnet with 1.5 wt.% Dy exhibits optimal magnetic properties. Further investigation presumed that Dy is enriched as (Nd, Dy){sub 2}Fe{sub 14}B phase in the surface region of the Nd{sub 2}Fe{sub 14}B matrix grains indicated by the enhancement of the magneto-crystalline anisotropy field of the Nd{sub 2}Fe{sub 14}B phase. As a result, the magnet doped with a small amount of Dy nanoparticles possesses remarkably enhanced coercivity without sacrificing its magnetization noticeably.

Evaluation of the exchange interaction and crystal fields in a prototype Dy2 SMM

Science.gov (United States)