Kondo effect and heavy fermions in Yb compounds

International Nuclear Information System (INIS)

Bonville, P.

1987-01-01

The Kondo properties of Yb dilute alloys and intermetallics have been investigated using Moessbauer spectroscopy on 170 Yb. In the dilute alloys AuYb and LaBe 13 Yb, the Kondo logarithmic anomaly of the impurity relaxation rate has been detected, and in the concentrated Yb compounds YbBe 13 , YbP and YbAs, and YbCuAl, the manifestations of the interplay between the Kondo effect and the magnetic ordering due to the RKKY interaction have been characterized

Growth, characterization, and waveguide lasing of Yb3+, Lu3+, Gd3+ co-doped KY(WO4)2 thin layers

NARCIS (Netherlands)

Aravazhi, S.; Geskus, D.; Günther, D.; Worhoff, Kerstin; Pollnau, Markus

2009-01-01

Monoclinic crystals of KY(WO4)2 (KYW) doped with different rare-earth ions are among the highly promising materials for building compact solid-state lasers. We report the liquid phase epitaxy (LPE) growth of 3-5 µm thick KYW:Gd3+, Lu3+, Yb3+ layers for Yb3+ concentrations of 1.2, 1.7, and 2.4 mol%

Structure and thermal expansion of Lu2O3 and Yb2O3 up to the melting points

Science.gov (United States)

Pavlik, Alfred; Ushakov, Sergey V.; Navrotsky, Alexandra; Benmore, Chris J.; Weber, Richard J. K.

2017-11-01

Knowledge of thermal expansion and high temperature phase transformations is essential for prediction and interpretation of materials behavior under the extreme conditions of high temperature and intense radiation encountered in nuclear reactors. Structure and thermal expansion of Lu2O3 and Yb2O3 were studied in oxygen and argon atmospheres up to their melting temperatures using synchrotron X-ray diffraction on laser heated levitated samples. Both oxides retained the cubic bixbyite C-type structure in oxygen and argon to melting. In contrast to fluorite-type structures, the increase in the unit cell parameter of Yb2O3 and Lu2O3 with temperature is linear within experimental error from room temperature to the melting point, with mean thermal expansion coefficients (8.5 ± 0.6) · 10-6 K-1 and (7.7 ± 0.6) · 10-6 K-1, respectively. There is no indication of a superionic (Bredig) transition in the C-type structure or of a previously suggested Yb2O3 phase transformation to hexagonal phase prior to melting.

Single Crystal Growth of Multiferroic Double Perovskites: Yb2CoMnO6 and Lu2CoMnO6

Directory of Open Access Journals (Sweden)

Hwan Young Choi

2017-02-01

Full Text Available We report on the growth of multiferroic Yb2CoMnO6 and Lu2CoMnO6 single crystals which were synthesized by the flux method with Bi2O3. Yb2CoMnO6 and Lu2CoMnO6 crystallize in a double-perovskite structure with a monoclinic P21/n space group. Bulk magnetization measurements of both specimens revealed strong magnetic anisotropy and metamagnetic transitions. We observed a dielectric anomaly perpendicular to the c axis. The strongly coupled magnetic and dielectric states resulted in the variation of both the dielectric constant and the magnetization by applying magnetic fields, offering an efficient approach to accomplish intrinsically coupled functionality in multiferroics.

Thermal properties and continuous-wave laser performance of Yb:LuVO4 crystal

Science.gov (United States)

Cheng, Y.; Zhang, H. J.; Yu, Y. G.; Wang, J. Y.; Tao, X. T.; Liu, J. H.; Petrov, V.; Ling, Z. C.; Xia, H. R.; Jiang, M. H.

2007-03-01

A laser crystal of Yb:LuVO4 with high optical quality was grown by the Czochralski technique. Its thermal properties including specific heat, thermal expansion coefficients, and thermal conductivities along the a- and c-axis have been measured for the first time. Continuous-wave laser output up to 3.5 W at 1031 nm was obtained at room temperature through end-pumping by a high-power diode laser. The corresponding optical conversion efficiency was 43% and the slope efficiency was 72%.

Investigation of Anderson lattice behavior in Yb1-xLuxAl3

International Nuclear Information System (INIS)

Bauer, E.D.; Booth, C.H.; Lawrence, J.M.; Hundley, M.F.; Sarrao, J.L.; Thompson, J.D.; Riseborough, P.S.; Ebihara, T.

2003-01-01

Measurements of magnetic susceptibility χ(T), specific heat C(T), Hall coefficient R H (T), and Yb valence ν = 2 + n f [f-occupation number n f (T) determined from Yb L 3 x-ray absorption measurements] were carried out on single crystals of Yb 1-x Lu x Al 3 . The low temperature anomalies observed in χ(T) and C(T) corresponding to an energy scale T coh ∼ 40 K in the intermediate valence, Kondo lattice compound YbAl 3 are suppressed by Lu concentrations as small as 5% suggesting these low-T anomalies are extremely sensitive to disorder and, therefore, are a true coherence effect. By comparing the temperature dependence of various physical quantities to the predictions of the Anderson Impurity Model, the slow crossover behavior observed in YbAl 3 , in which the data evolve from a low-temperature coherent, Fermi-liquid regime to a high temperature local moment regime more gradually than predicted by the Anderson Impurity Model, appears to evolve to fast crossover behavior at x ∼ 0.7 where the evolution is more rapid than predicted. These two phenomena found in Yb 1-x Lu x Al 3 , i.e., the low-T anomalies and the slow/fast crossover behavior are discussed in relation to recent theories of the Anderson lattice

Emission properties of hydrothermal Yb{sup 3+}, Er{sup 3+} and Yb{sup 3+}, Tm{sup 3+}-codoped Lu{sub 2}O{sub 3} nanorods: upconversion, cathodoluminescence and assessment of waveguide behavior

Energy Technology Data Exchange (ETDEWEB)

Barrera, Elixir William; Pujol, MarIa Cinta; DIaz, Francesc [Fisica i Cristal.lografia de Materials, Universitat Rovira i Virgili, Campus Sescelades c/ Marcel.lI Domingo s/n, E-43007 Tarragona (Spain); Choi, Soo Bong; Rotermund, Fabian [Division of Energy Systems Research, Ajou University, 443-749 Suwon (Korea, Republic of); Park, Kyung Ho [Korea Advanced Nano Fab Center, 443-270 Suwon (Korea, Republic of); Jeong, Mun Seok [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 500-712 Gwangju (Korea, Republic of); Cascales, Concepcion, E-mail: ccascales@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones CientIficas, c/Sor Juana Ines de la Cruz, 3 Cantoblanco, E-28049 Madrid (Spain)

2011-02-18

Yb{sup 3+} and Ln{sup 3+} (Ln{sup 3+} = Er{sup 3+} or Tm{sup 3+}) codoped Lu{sub 2}O{sub 3} nanorods with cubic Ia3-bar symmetry have been prepared by low temperature hydrothermal procedures, and their luminescence properties and waveguide behavior analyzed by means of scanning near-field optical microscopy (SNOM). Room temperature upconversion (UC) under excitation at 980 nm and cathodoluminescence (CL) spectra were studied as a function of the Yb{sup +} concentration in the prepared nanorods. UC spectra revealed the strong development of Er{sup 3+4}F{sub 9/2} {yields} 4I{sub 15/2} (red) and Tm{sup 3+1}G{sub 4} {yields} {sup 3}H{sub 6} (blue) bands, which became the pre-eminent and even unique emissions for corresponding nanorods with the higher Yb{sup 3+} concentration. Favored by the presence of large phonons in current nanorods, UC mechanisms that privilege the population of {sup 4}F{sub 9/2} and {sup 1}G{sub 4} emitting levels through phonon-assisted energy transfer and non-radiative relaxations account for these observed UC luminescence features. CL spectra show much more moderate development of the intensity ratio between the Er{sup 3+4}F{sub 9/2} {yields}{sup 4}I{sub 15/2} (red) and {sup 2}H{sub 11/2}, {sup 4}S{sub 3/2} {yields} {sup 4}I{sub 15/2} (green) emissions with the increase in the Yb{sup 3+} content, while for Yb{sup 3+}, Tm{sup 3+}-codoped Lu{sub 2}O{sub 3} nanorods the dominant CL emission is Tm{sup 3+1}D{sub 2} {yields} {sup 3}F{sub 4} (deep-blue). Uniform light emission along Yb{sup 3+}, Er{sup 3+}-codoped Lu{sub 2}O{sub 3} rods has been observed by using SNOM photoluminescence images; however, the rods seem to be too thin for propagation of light.

Radiation hardness of LuAG:Ce and LuAG:Pr scintillator crystals

CERN Document Server

Derdzyan, M V; Belsky, A; Dujardin, C; Lecoq, P; Lucchini, M; Ovanesyan, K L; Pauwels, K; Pedrini, C; Petrosyan, A G

2012-01-01

Single crystals of LuAG:Ce, LuAG:Pr and un-doped LuAG were grown by the vertical Bridgman method and studied for radiation hardness under gamma-rays with doses in the range 10-10(5) Gy (Co-60). A wide absorption band peaking at around 600 nm springs up in all three types of crystals after the irradiations. The second band peaking at around 375 nm appears in both LuAG:Pr and un-doped LuAG. Compositional variations have been done to reveal the spectral behavior of induced color centers in more detail and to understand their origin. Similarities in behavior of Yb2+ centers in as-grown garnets are found, indicating that radiation induced color centers can be associated with residual trace amounts of Yb present in the raw materials. Un-doped LuAG and LuAG:Ce demonstrate moderate radiation hardness (the induced absorption coefficients being equal to 0.05-0.08 cm(-1) for accumulated doses of 10(3)-10(4) Gy), while LuAG:Pr is less radiation hard. The ways to improve the radiation hardness are discussed.

Diode-pumped passively mode-locked sub-picosecond Yb:LuAG ceramic laser

International Nuclear Information System (INIS)

Zhu Jiang-Feng; Liu Kai; Wang Jun-Li; Yang Yu; Wang Hui-Bo; Gao Zi-Ye; Jiang Li; Xie Teng-Fei; Chao-Yu Li; Pan Yu-Bai; Wei Zhi-Yi

2017-01-01

In this paper the laser activities of a diode-pumped Yb:LuAG ceramic which was prepared by the solid-state reactive sintering method were reported. The maximum output power was 1.86 W in the continuous wave (CW) laser operation, corresponding to a slope efficiency of 53.6%. The CW laser could be tuned from 1030 to 1096 nm by inserting a prism in the cavity. With the assist of a semiconductor saturable absorber mirror (SESAM), passive mode-locking was realized, delivering sub-picosecond pulses with 933 fs duration and an average power of 532 mW at a repetition rate of 90.35 MHz. (paper)

Thermal evolution of the spin ordering at the concomitant spin–orbital rearrangement temperature in RVO{sub 3} (R=Lu, Yb and Tm)

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Tapati, E-mail: tapati.sarkar@angstrom.uu.se [Department of Engineering Sciences, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Ivanov, Sergey A. [Department of Engineering Sciences, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Center of Materials Science, Karpov Institute of Physical Chemistry, 105064 Moscow K-64 (Russian Federation); Bazuev, G.V. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Science, 620999 Ekaterinburg GSP-145 (Russian Federation); Nordblad, Per; Mathieu, Roland [Department of Engineering Sciences, Uppsala University, Box 534, SE-75121 Uppsala (Sweden)

2016-07-01

Synthesis, crystal structure and magnetization measurements of phase pure polycrystalline RVO{sub 3} (R=Lu, Yb and Tm) are reported. The compounds were stabilized in the orthorhombic structure by thermal treatment of the respective precursors (RVO{sub 4}) in a reducing atmosphere. Special pressure treatment was carried out during the synthesis to ensure phase pure samples without secondary phases. Magnetization measurements reveal the presence of two spin ordering temperatures in the samples. Interestingly, at the lower spin ordering temperature, T{sub SO2}, the uncompensated excess moment of the antiferromagnetic spin structure has different field dependences above and below T{sub SO2}, causing a jump in the thermal evolution of the magnetization that changes sign with increasing field strength. This jump is associated with the reported magnetic and orbital rearrangement in the samples, and the different spin configurations in the C- and G-type antiferromagnetic structures. - Highlights: • Magnetization measurements of polycrystalline RVO{sub 3} (R=Lu, Yb, Tm) are reported. • The samples have two spin ordering temperatures, T{sub SO1} and T{sub SO2} (T{sub SO1}>T{sub SO2}). • A magnetic field dependent jump of the excess magnetization, ΔM is observed at T{sub SO2.} • The jump in ΔM is associated with magnetic and orbital rearrangement in the samples. • ΔM is probably affected by possible phase coexistence in the samples.

Measurements of Coster-Kronig enhancement factors for Yb, Lu, Os and Pt elements

International Nuclear Information System (INIS)

Yilmaz, R.; Oz, E.; Tan, M.; Durak, R.; Demirel, A.I.; Sahin, Y.

2009-01-01

In this work X-ray production cross-sections' measurements, L ι , L α , L β and L γ , of Yb, Lu, Os and Pt elements have been studied at energies in the range 9.572-14.384 keV and the effect of Coster-Kronig transitions on fluorescence cross-sections for L X-ray line has been obtained. From these studies absolute values of L X-ray cross-sections have been calculated with incorporation of the enhancement due to the Coster-Kronig effect. The experimental enhancement factors tend to be smaller than those predicted by theory.

Measurements of Coster-Kronig enhancement factors for Yb, Lu, Os and Pt elements

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, R. [Department of Physics, Faculty of Sciences and Arts, Yuezuencue Yil University, 65080 Van (Turkey)], E-mail: ryilmaz@yyu.edu.tr; Oz, E. [Department of Physics, Faculty of Sciences and Arts, 25240 Erzurum (Turkey); Tan, M. [Department of Physics, Faculty of Education, Gazi University, 06500 Ankara (Turkey); Durak, R. [Department of Physics, Faculty of Sciences and Arts, 25240 Erzurum (Turkey); Demirel, A.I. [Department of Physics, Faculty of Sciences and Arts, Yuezuencue Yil University, 65080 Van (Turkey); Sahin, Y. [Department of Physics, Faculty of Sciences and Arts, 25240 Erzurum (Turkey)

2009-05-15

In this work X-ray production cross-sections' measurements, L{sub {iota}}, L{sub {alpha}}, L{sub {beta}} and L{sub {gamma}}, of Yb, Lu, Os and Pt elements have been studied at energies in the range 9.572-14.384 keV and the effect of Coster-Kronig transitions on fluorescence cross-sections for L X-ray line has been obtained. From these studies absolute values of L X-ray cross-sections have been calculated with incorporation of the enhancement due to the Coster-Kronig effect. The experimental enhancement factors tend to be smaller than those predicted by theory.

Synthesis of NaLuF4:Er3+, Yb3+, Ce3+ nanoparticles and study of photoluminescent properties in C - band

Directory of Open Access Journals (Sweden)

Khaydukov K.V.

2017-01-01

Full Text Available The novel core@shell nanocrystals β-NaLuF4@NaLuF4 co-doped with rare-earth ions Er3+, Yb3+, Ce3+ have been synthesized. The nano-particles indicate the intensive lines of anti-Stokes luminescence in the telecommunication С - band of spectrum when pumped at 970-980 nm. The nanoparticles have been characterized by transmission electron microscopy and spectrofluorimetry. The nanoparticles have a size 40-80 nm and possess the intensive photo-luminescence 73 nm bandwidth centered around 1530 nm. The photo-luminescence kinetics of β-NaLuF4: Er3+/ Yb3+/ Ce3+ has been studied in IR range of spectrum. We have demonstrated that doping with cerium ions prevents serial stepwise excitation of erbium ions. Consequently, the lifetime of transition in erbium 4I13/2→4I15/2 has risen up to 6.9 ms. Intensity of 1530 nm line in Er3+ ions excited at 980 nm has been increased up to 6 times. Therefore, the nanoparticles are applicable to fabrication of compact waveguide amplifiers for C - band.

The physical and chemical characteristics of 175Yb-EDTMP labelled compound

International Nuclear Information System (INIS)

Azmairit Aziz; Marlina; Muhammad Basit Febrian

2010-01-01

Bone pain is a common complication for patient with bone metastases from breasts, prostate and lung cancers. The derivative of phosphonate groups, i.e. diphosphonate as well as poly phosphonate ligands e.g. EDTMP have high affinity in bone matrix. The labeled compound of 175 Yb-EDTMP can be used as an alternative radiopharmaceutical for bone pain palliation. The compound of 175 Yb-EDTMP can be produced by labeling of ethylenediamine tetramethylene phosphonic acid (EDTMP) with itterbium-175 ( 175 YbCl 3 ). Before 175 Yb-EDTMP is used for bone pain palliation in nuclear medicine, the compound have to be characterized to full fill the criteria of the good radiopharmaceutical. The physical and chemical characteristics of 175 Yb-EDTMP had been studied. It consists of: pH, solution clearity, the radiochemical purity that was determined by paper chromatography and paper electrophoresis techniques, electricity charge was determined by paper electrophoresis, stability, lipophilicity of 175 Yb-EDTMP was obtained by determination of octanol-water partition and the plasma binding protein was in-vitro investigated with precipitation method using 5% of trichloroacetic acid solution, and the binding to hydroxyapatite. From the experiment, it was obtained that the 175 Yb-EDTMP solution has the pH of 7, clear, the radiochemical purity of 98.66 ± 0.53%, and the negative electric charge. The compound of 175 Yb-EDTMP has lipophilicity (P) of 0.0135 ± 0.003%, the human plasma binding protein of 8.94 ± 0.66%, and the hydroxyapatite binding of 94.78 ± 2.16%. Stability evaluation indicated that 175 Yb-EDTMP solution was still stable for nine days at room temperature with the radiochemical purity more than 95% (98.62 ± 0.83%). This study expects that 175 Yb-EDTMP compound can fulfill the requirement as radiopharmaceutical for use in palliative treatment of painful bone metastases and supports the development of nuclear medicine in Indonesia. (author)

Two-step photoconductivity in LiY x Lu1 - x F4:Ce,Yb crystals

Science.gov (United States)

Nurtdinova, L. A.; Korableva, S. L.; Leontiev, A. V.

2016-10-01

Photoconductivity of LiY x Lu1- x F4:Ce,Yb ( x = 0-1) crystals is measured under one- and two-step excitation. It is established that the photoconductivity is due to intra-center transitions from excited states of Ce3+ ions. The position of the ground 4 f-state of Ce3+ ion relative to the bottom of the conduction band is determined. The choice of pumping conditions to obtain the lasing on the 5 d-4 f transitions of trivalent cerium in these active media is substantiated.

Study on the eγ coincidences in the 169Lu decay

International Nuclear Information System (INIS)

Batsev, S.; Bonch-Osmolovskaya, N.A.; Budzyak, A.; Kuznetsov, V.V.; Usmanov, R.R.

1979-01-01

The 169 Lu→ 169 Yb decay scheme was analyzed on the basis of measurements of eγ coincidence. The 169 Lu sources were obtained by irradiating a tantalum target by 660 MeV protons. The eγ-coincidence spectra were measured by an ironless β-spectrometer with a toroidal magnetic field and a detector. The γ-ray and eγ-coincidence spectra were processed by a computer. The results of processing the 169 Lu coincidence spectra are tabulated. No excited states of 169 Yb not confirmed by γγ and eγ coincidences (except for the head level of the 3/2 + (651) 720 keV band) remain in the 169 Lu decay scheme proposed. Weak transitions with the total intensity of no more than 3.3% per a 169 Lu decay have remained unarranged, they should discharge weakly excited levels of 169 Yb. Probabilities of the 169 Yb level population per a 169 Lu decay and the corresponding values of probabilities of transitions in them are presented. As a whole, the 169 Lu decay scheme involves 60 levels, 31 states of them are new

Yb-based heavy fermion compounds and field tuned quantum chemistry

Energy Technology Data Exchange (ETDEWEB)

Mun, Eundeok [Iowa State Univ., Ames, IA (United States)

2010-01-01

The motivation of this dissertation was to advance the study of Yb-based heavy fermion (HF) compounds especially ones related to quantum phase transitions. One of the topics of this work was the investigation of the interaction between the Kondo and crystalline electric field (CEF) energy scales in Yb-based HF systems by means of thermoelectric power (TEP) measurements. In these systems, the Kondo interaction and CEF excitations generally give rise to large anomalies such as maxima in ρ(T) and as minima in S(T). The TEP data were use to determine the evolution of Kondo and CEF energy scales upon varying transition metals for YbT₂Zn₂₀ (T = Fe, Ru, Os, Ir, Rh, and Co) compounds and applying magnetic fields for YbAgGe and YbPtBi. For YbT₂Zn₂₀ and YbPtBi, the Kondo and CEF energy scales could not be well separated in S(T), presumably because of small CEF level splittings. A similar effect was observed for the magnetic contribution to the resistivity. For YbAgGe, S(T) has been successfully applied to determine the Kondo and CEF energy scales due to the clear separation between the ground state and thermally excited CEF states. The Kondo temperature, T_K, inferred from the local maximum in S(T), remains finite as magnetic field increases up to 140 kOe. In this dissertation we have examined the heavy quasi-particle behavior, found near the field tuned AFM quantum critical point (QCP), with YbAgGe and YbPtBi. Although the observed nFL behaviors in the vicinity of the QCP are different between YbAgGe and YbPtBi, the constructed H-T phase diagram including the two crossovers are similar. For both YbAgGe and YbPtBi, the details of the quantum criticality turn out to be complicated. We expect that YbPtBi will provide an additional example of field tuned quantum criticality, but clearly there are further experimental investigations left and more ideas needed to understand the basic physics of field-induced quantum

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).

Characterization of the lasing properties of a 5%Yb doped Lu.sub.2./sub.SiO.sub.5./sub. crystal along its three optical axes

Czech Academy of Sciences Publication Activity Database

Toci, G.; Pirri, A.; Beitlerová, Alena; Shoji, Y.; Yoshikawa, A.; Hybler, Jiří; Nikl, Martin; Vannini, M.

2015-01-01

Roč. 23, č. 10 (2015), s. 13210-13221 ISSN 1094-4087 Institutional support: RVO:68378271 Keywords : Lu 2 SiO 5 * Yb-doped * laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.148, year: 2015

On the valence state of Yb and Ce in transition metal intermetallic compounds

International Nuclear Information System (INIS)

Boer, F.R. de; Dijkman, W.H.; Mattens, W.C.M.

1979-01-01

In the pure state Yb is a divalent metal, similar to Ca; in alloys it can become trivalent like the majority of the rare earth metals. Using a value of 38 kJ (mol Yb) -1 for the energy difference between divalent and trivalent Yb metal and using model calculations for the heat of formation of intermetallic compounds, the authors are able to account for the existing information on the valence state of Yb in transition metal compounds. A similar analysis of compounds of Ce with transition metals shows that a model in which the 4f electron is treated as a core electron, i.e. being absent in the tetravalent modification of Ce and present as a fully localized electron in trivalent Ce, does not apply. (Auth.)

Synthesis of Multicolor Core/Shell NaLuF4:Yb3+/Ln3+@CaF2 Upconversion Nanocrystals

Directory of Open Access Journals (Sweden)

Hui Li

2017-02-01

Full Text Available The ability to synthesize high-quality hierarchical core/shell nanocrystals from an efficient host lattice is important to realize efficacious photon upconversion for applications ranging from bioimaging to solar cells. Here, we describe a strategy to fabricate multicolor core @ shell α-NaLuF4:Yb3+/Ln3+@CaF2 (Ln = Er, Ho, Tm upconversion nanocrystals (UCNCs based on the newly established host lattice of sodium lutetium fluoride (NaLuF4. We exploited the liquid-solid-solution method to synthesize the NaLuF4 core of pure cubic phase and the thermal decomposition approach to expitaxially grow the calcium fluoride (CaF2 shell onto the core UCNCs, yielding cubic core/shell nanocrystals with a size of 15.6 ± 1.2 nm (the core ~9 ± 0.9 nm, the shell ~3.3 ± 0.3 nm. We showed that those core/shell UCNCs could emit activator-defined multicolor emissions up to about 772 times more efficient than the core nanocrystals due to effective suppression of surface-related quenching effects. Our results provide a new paradigm on heterogeneous core/shell structure for enhanced multicolor upconversion photoluminescence from colloidal nanocrystals.

Nuclear spectroscopic studies in 162Yb

International Nuclear Information System (INIS)

Behrens, H.

1980-01-01

The decay of the highly excited 162 Yb nuclei formed in the reaction 150 Sm( 16 O,4n) 162 Yb to the ground state was studied using different gamma detectors and an electron spectrometer, a so called mini-orange. The isotope 162 Yb was moreover produced and spectroscoped by the beta-decay of 162 Lu. For the identification of decay cascades, which were passed after the fusion, and for the determination of the multipolarity of the contributing energy transitions a series of experiments took place: The excitation functions and the angular distributions of the emitted gamma radiation was measured, the conversion coefficients of important transitions were determined, and coincidence events between two detectors occasionally were registrated and analyzed. In the beta decay measurement an assignment of gamma transitions to 162 Yb followed due to the lifetime, under which they occured. The found states of 162 Yb upto spins of 22 h/2π and excitation energies above 5 MeV belong to five rotational bands. The yrast band shows a weak backbending. Corresponding to their spins and parities the bands can be reduced to intrinsic excitation of two quasineutrons. The analysis of the beta-decay of 162 Lu, which takes place from three states in 162 Lu, leads to the lowest levels of the gamma-vibrational band and the band head of the beta band. The microscopic interpretation of the rotational bands and the description of the backbending behaviour are as the interpretation of the states involved at the beta decay in agreement with experimental and theoretical results for neighbouring ytterbium isotopes. (orig.) [de

Enhancement of red upconversion emission of cubic phase NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Gao, Wei, E-mail: gaowei@xupt.edu.com; Dong, Jun, E-mail: dongjun@xupt.edu.cn; Liu, Jihong; Yan, Xuewen

2016-08-15

Highlights: • The upconversion emission of Ho{sup 3+} ions was tuned from green to red. • The upconversion mechanism of Ho{sup 3+} ions was discussed based on emission spectrum. • The conversion efficiency between Ho{sup 3+} and Ce{sup 3+} were studied and calculated. - Abstract: The red upconversion emission of lanthanide-doped fluoride nanocrystals have great potential applications in color display and anticounterfeiting applications, especially for biological imaging and biomedical. In this work, a significant enhancement of red upconversion emission of Ho{sup 3+} ions was successfully obtained in the cubic phase NaLuF{sub 4} nanocrystals through codoping Ce{sup 3+} ions under NIR 980 nm excitation. The ratio of red-to-green emission of Ho{sup 3+} ions was enhanced about 10-fold, which is due to two efficient cross relaxation processes derived from Ho{sup 3+} and Ce{sup 3+} ions promoted the red emission and quenched the green emission. The upconversion emission and luminescent colors of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} nanocrystals were carefully investigated by a confocal microscopy setup. The possible upconversion emission mechanism and conversion efficiency of cross relaxation between Ho{sup 3+} and Ce{sup 3+} ions were discussed in detail. The current study suggests that strong red emission of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanomaterials can be used for color display and anticounterfeiting techniques.

Magnetic structure of the YbMn2SbBi compound

International Nuclear Information System (INIS)

Morozkin, A.V.; Manfrinetti, P.

2011-01-01

Graphical abstract: Display Omitted Research highlights: → A neutron diffraction investigation in zero applied field of La 2 O 2 S-type YbMn 2 SbBi shows antiferromagnetic ordering below 138(3) K and ferrimagnetic ordering below 112(3) K. → Between 138 and 112 K, the magnetic structure of YbMn 2 SbBi consists of antiferromagnetically coupled ab-plane magnetic moments of the manganese atoms (D 1d magnetic point group). → Below 112(3) K, the magnetic structure of YbMn 2 SbBi becames the sum antiferromagnetic component with D 1d magnetic point group and ferromagnetic one with C 2 magnetic point group. → The magnitude of Yb and Mn magnetic moments in YbMn 2 SbBi at 2 K (M Yb = 3.6(2) μ B , M Mn = 3.5(2) μ B ) correspond to the trivalent state of the Yb ions and tetravalent state of the Mn ions. - Abstract: A neutron diffraction investigation has been carried out on the trigonal La 2 O 2 S-type (hP5, space group P3-bar ml, No. 164; also CaAl 2 Si 2 -type) YbMn 2 SbBi intermetallic compound. The YbMn 2 SbBi presents antiferromagnetic ordering below 138(3) K and ferrimagnetic ordering below 112(3) K. Between 138 and 112 K, the magnetic structure of YbMn 2 SbBi consists of antiferromagnetically coupled ab-plane magnetic moments of the manganese atoms (D 1d magnetic point group). Below 112(3) K, the ferromagnetic components of Yb and Mn begin to develop, and the magnetic structure of YbMn 2 SbBi becames the sum antiferromagnetic component with D 1d magnetic point group and ferromagnetic one with C 2 magnetic point group. The magnitude of Yb and Mn magnetic moments in YbMn 2 SbBi at 2 K (M Yb = 3.6(2) μ B , M Mn = 3.5(2) μ B ) correspond to the trivalent state of the Yb ions and tetravalent state of the Mn ions.

Growth, crystal structure, spectral properties and laser performance of Yb3+:NaLu(MoO4)2 crystal

International Nuclear Information System (INIS)

Yu, Yi; Zhang, Lizhen; Huang, Yisheng; Lin, Zhoubin; Wang, Guofu

2013-01-01

A double molybdate Yb 3+ :NaLu(MoO 4 ) 2 crystal was successfully grown from a flux of Na 2 Mo 2 O 7 by the top-seeded solution growth method, for the first time to our knowledge. The crystal belongs to the tetragonal system with space group I4 1 /a, and the unit-cell parameters are a = b = 5.159 Å, c = 11.246 Å. Na and Lu atoms co-occupy the same lattice site, which leads to the disordered structure of NaLu(MoO 4 ) 2 crystal. The thermal expansion coefficients of the crystal are 1.35 × 10 −5 K −1 along the c-axis, and 1.01 × 10 −5 K −1 along the a-axis. The full-width at half-maximum of the emission bands are 67 nm for the σ-polarization and 50 nm for the π-polarization at about 1020 nm. The maximum emission cross-sections for the σ- and π-polarizations are 2.79 × 10 −20 cm 2 and 2.94 × 10 −20 cm 2 , respectively. 0.3 W output power at 1025 nm was obtained at an absorbed pump power of 1.7 W, with a slope efficiency of 24%. (paper)

Growth, crystal structure, spectral properties and laser performance of Yb3+:NaLu(MoO4)2 crystal

Science.gov (United States)

Yu, Yi; Zhang, Lizhen; Huang, Yisheng; Lin, Zhoubin; Wang, Guofu

2013-10-01

A double molybdate Yb3+:NaLu(MoO4)2 crystal was successfully grown from a flux of Na2Mo2O7 by the top-seeded solution growth method, for the first time to our knowledge. The crystal belongs to the tetragonal system with space group I41/a, and the unit-cell parameters are a = b = 5.159 Å, c = 11.246 Å. Na and Lu atoms co-occupy the same lattice site, which leads to the disordered structure of NaLu(MoO4)2 crystal. The thermal expansion coefficients of the crystal are 1.35 × 10-5 K-1 along the c-axis, and 1.01 × 10-5 K-1 along the a-axis. The full-width at half-maximum of the emission bands are 67 nm for the σ-polarization and 50 nm for the π-polarization at about 1020 nm. The maximum emission cross-sections for the σ- and π-polarizations are 2.79 × 10-20 cm2 and 2.94 × 10-20 cm2, respectively. 0.3 W output power at 1025 nm was obtained at an absorbed pump power of 1.7 W, with a slope efficiency of 24%.

Thermal and electron transport studies on the valence fluctuating compound YbNiAl4

Science.gov (United States)

Falkowski, M.; Kowalczyk, A.

2018-05-01

We report the thermoelectric power S and thermal conductivity κ measurements on the valence fluctuating compound YbNiAl4, furthermore taking into account the impact of the applied magnetic field. We discuss our new results with revisiting the magnetic [χ(T)], transport [ρ(T)], and thermodynamic [Cp(T)] properties in order to better understand the phenomenon of thermal and electron transport in this compound. The field dependence of the magnetoresistivity data is also given. The temperature dependence of thermoelectric power S(T) was found to exhibit a similar behaviour as expected for Yb-based compounds with divalent or nearly divalent Yb ions. In addition, the values of total thermal conductivity as a function of temperature κ(T) of YbNiAl4 are fairly low compared to those of pure metals which may be linked to the fact that the conduction band is perturbed by strong hybridization. A deeper analysis of the specific heat revealed the low-T anomaly of the ratio Cp(T)/T3, most likely associated with the localized low-frequency oscillators in this alloy. In addition, the Kadowaki-Woods ratio and the Wilson ratio are discussed with respect to the electronic correlations in YbNiAl4.

Electron spin resonance in Yb-based Kondo-lattice systems; Elektronenspinresonanz in Yb-basierten Kondogitter-Systemen

Energy Technology Data Exchange (ETDEWEB)

Wykhoff, Jan

2010-07-07

The systems Yb{sub 1-w}A{sub 1-w}(Rh{sub 1-x}Co{sub x})(Si{sub 1-y}Ge{sub y}){sub 2} with A=La respectively Lu, as well as YbIr{sub 2}Si{sub 2} are studied. The measurements are presented sortedly for systems, dopings, and external parameters. Beside these external parameters furthermore the orientation of the sample related to the quasistatic magnetic field and the microwave magnetic field was varied.

β decays on the rotational levels of the 5/2+[642] 169Yb band

International Nuclear Information System (INIS)

Dzhelepov, B.S.; Zhukovskij, N.N.; Shestopalova, S.A.

1993-01-01

Competing 169 Lu β decays into rotational levels of 5/2 + [642] 169 Yb band are considered. Schemes of resolved β decay into 3 levels of deformed nucleus rotational bands, γ transitions linked with excitation and discharge of 169 Yb 5/2, 7/2, 9/2, 5/2 + [642] levels are presented. Matrix elements of axial-vector decay are determined. Data on 12 γ transitions in 169 Lu are presented

Hydrothermal synthesis of NaLuF4:153Sm,Yb,Tm nanoparticles and their application in dual-modality upconversion luminescence and SPECT bioimaging.

Science.gov (United States)

Yang, Yang; Sun, Yun; Cao, Tianye; Peng, Juanjuan; Liu, Ying; Wu, Yongquan; Feng, Wei; Zhang, Yingjian; Li, Fuyou

2013-01-01

Upconversion luminescence (UCL) properties and radioactivity have been integrated into NaLuF(4):(153)Sm,Yb,Tm nanoparticles by a facile one-step hydrothermal method, making these nanoparticles potential candidates for UCL and single-photon emission computed tomography (SPECT) dual-modal bioimaging in vivo. The introduction of small amount of radioactive (153)Sm(3+) can hardly vary the upconversion luminescence properties of the nanoparticles. The as-designed nanoparticles showed very low cytotoxicity, no obvious tissue damage in 7 days, and excellent in vitro and in vivo performances in dual-modal bioimaging. By means of a combination of UCL and SPECT imaging in vivo, the distribution of the nanoparticles in living animals has been studied, and the results indicated that these particles were mainly accumulated in the liver and spleen. Therefore, the concept of (153)Sm(3+)/Yb(3+)/Tm(3+) co-doped NaLuF(4) nanoparticles for UCL and SPECT dual-modality imaging in vivo of whole-body animals may serve as a platform for next-generation probes for ultra-sensitive molecular imaging from the cellular scale to whole-body evaluation. It also introduces an easy methodology to quantify in vivo biodistribution of nanomaterials which still needs further understanding as a community. Copyright © 2012 Elsevier Ltd. All rights reserved.

Alloying of Yb-Cu and Yb-Ag utilizing liquid ammonia metal solutions of ytterbium

International Nuclear Information System (INIS)

Imamura, H.; Yoshimura, T.; Sakata, Y.

2003-01-01

In the course of the studies on preparation of novel compounds using the dissolution of Eu or Yb metals in liquid ammonia, the formation of Yb-Cu and Yb-Ag intermetallic films has been found. When Cu or Ag metal powders were placed in a reactor containing a solution of Yb metal in liquid ammonia, the dissolved Yb readily react with the Cu or Ag metal particles to form surface alloy compounds. X-ray diffraction of Yb-Cu showed that upon thermal treatment above 673 K, the Yb metal deposited on the Cu particles reacted together to be transformed into the YbCu 6.5 intermetallic compound. A characteristic endothermic peak at 749 K, due to alloying of Yb-Cu, was observed by the differential scanning calorimeter measurements. By use of the high reactivity of liquid ammonia metal solutions of ytterbium, it was found that the ytterbium intermetallic films were readily formed under mild conditions. Yb-Cu and Yb-Ag exhibited enhanced catalytic activity for the hydrogenation of ethene as a result of alloying

Spectroscopic characterization and temporal dynamics of energy transfer process between Tm3+ -Ho3+ and Yb3+ -Tm3+ ions in LiYF4 and LiLuF4 crystals

International Nuclear Information System (INIS)

Tarelho, Luiz Vicente Gomes

2001-01-01

In this work, we perform spectroscopic studies to characterize the energy transfer processes occurring in rare-earth doped lithium fluoride systems, aiming the optimization of the population inversion of these media. Yb 3+ ion was used in order to probe the electron-phonon coupling in LiYF 4 , LiGdF 4 and LiLuF 4 matrices. In these systems it was obtained the average phononenergy, the vibronic transition probability and Huang-Rhys coupling constant. These parameters are dependent on the crystal host and the LiLuF 4 system presents excluded correlation effects, an electronic repulsion that weakens the vibronic coupling. The Tm:Ho:LiYF 4 system was studied under diode laser pumping at 796 nm, aiming the 2 μm emission optimization. The ideal conditions of concentration and laser power were determined favouring the latter emission. Upconversion processes of two photons were identified besides the energy transfer among ions. The dynamic processes of luminescence of donors and acceptors allowed one to classify the energy transfer process as an energy transfer process assisted by fast diffusion among donors. The spectroscopic study of the Yb:Tm:LiYF 4 allowed the determination of efficient non resonant transfer mechanisms between ( 2 F 5/2 ) Ytterbium level and ( 3 H 5 ) Thulium level, assisted by two phonon with hopping migration among donors ( Foerster-Burshtein model). The repopulation process of the Yb donor level is due to a cooperative sensitization between Yb-Tm pairs followed by an energy transfer process. (author)

New configurations for short-pulses high power solid-state lasers: conception and realization of highly doped waveguide amplifiers/lasers grown by liquid phase epitaxy and demonstration of Y2SiO5: Yb and Lu2SiO5: Yb femtosecond lasers

International Nuclear Information System (INIS)

Thibault, F.

2006-04-01

Yb-doped yttrium and lutetium ortho-silicates, Y 2 SiO 5 :Yb and Lu 2 SiO 5 :Yb respectively, exhibit spectroscopic properties favorable to an efficient laser operation in both high power cw and femtosecond regime. Their first diode-pumped femtosecond operation demonstration lead to exceptional performances in terms of output power and efficiency. In order to realize compact and efficient solid-state laser devices using those materials, we chose a configuration with an Yb-doped medium planar waveguide geometry, grown by liquid phase epitaxy, face-pumped by a single laser diode bar. The growth of highly doped Y 2 SiO 5 :Yb layers, within a large range of compositions and thicknesses, was demonstrated. The refractive index increase due to the substitution of the various dopants is analyzed. The layers spectroscopic properties are similar to the bulk ones, with an noticeably higher crystalline quality. The Yb ion lifetime evolution with respect to its doping shows up a particularly low decrease, proof of a low concentration of extrinsic quenching centers. The covered YSO:24%Yb waveguides exhibit lower than 0.3 dB/cm propagation losses, and provided up to 2.9 dB/cm net amplification at 1082 nm with a single mode output. The realization of the first diode-pumped monolithic cw waveguide lasers was also demonstrated. For a 4% output coupler, they provided up to 340 mW at 1082 nm with a 14% slope efficiency. (author)

Electron spin resonance in Yb-based Kondo-lattice systems

International Nuclear Information System (INIS)

Wykhoff, Jan

2010-01-01

The systems Yb 1-w A 1-w (Rh 1-x Co x )(Si 1-y Ge y ) 2 with A=La respectively Lu, as well as YbIr 2 Si 2 are studied. The measurements are presented sortedly for systems, dopings, and external parameters. Beside these external parameters furthermore the orientation of the sample related to the quasistatic magnetic field and the microwave magnetic field was varied.

Thiocarbomide coordination compounds of yttrium subgroup rare earth chlorides

International Nuclear Information System (INIS)

Sakharova, Yu.G.; Perov, V.N.; Loginov, V.I.

1978-01-01

Thiocarbamide coordination compounds of chlorides of elements of the yttrium subgroup 4MeCl 3 x5Cs(NH 2 ) 2 x2OH 2 O (where Me stands for Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) were produced for the first time. The compounds obtained are stable in air, have definite melting points, are highly soluble in methyl and ethyl alcohols, and are unstable in water. They recrystallize from ethyl alcohol without changing their chemical composition. The identity of these compounds was confirmed by X-ray analysis

Study on preparation of 17'7Lu, labeling with DOTATATE for using in diagnosis and treatment neuroendocrine tumors

International Nuclear Information System (INIS)

Duong Van Dong; Bui Van Cuong; Pham Ngoc Dien; Chu Van Khoa; Mai Phuoc Tho; Nguyen Thi Thu; Vo Thi Cam Hoa

2014-01-01

Due to its physical and chemical characteristics, 177 Lu is a very attractive radionuclide for use in nuclear medicine. Its main usage is in the treatment of neuroendocrine tumours but its applicability in the treatment of colon cancer, metastatic bone cancer, non-Hodgkin lymphoma, lung, ovarian, and prostate cancer, has also been studied. Two alternative production routes are generally applied to obtain 177 Lu, namely the direct route based on neutron irradiation of lutetium targets and the indirect route based on neutron irradiation of ytterbium targets followed by radiochemical separation of 177 Lu from ytterbium isotopes. The comparison of theoretically calculated and experimentally determined yield for 176 Lu(n,γ) 177 Lu reaction is presented. 177 Lu could be produced with a specific activity of 42 mCi/mg by neutron activation using enriched 176 Lu (2.59%) target when irradiation was carried out at Dalat Nuclear Research Reactor with thermal neutron flux of 2x10 13 n.cm -2 .s -1 for 100 hours. The indirect production route as an alternative production route, 177 Lu could be obtained as carrier-free from beta decay of 177 Yb produced by neutron activation of 176 Yb. In this way, enriched target material was used but it may be the neutron capture cross section is only 2.4 barn so resulting in low activity just enough to study the separation process of 177 Lu from 177 Yb. In the other hand the study on labeling 177 Lu with DOTATATE is also described the optimization of the reaction conditions to obtain the complex 177 Lu-DOTATATE with a radiochemical purity > 99%, even so the studies of stability in vitro to the dilution in saline solution during 72 hours. The bio-distribution studies of this product in mice and rabbit are also investigated. (author)

Analysis of heat capacity and Mössbauer data for LuZnSn2 compound

Directory of Open Access Journals (Sweden)

Łątka Kazimierz

2015-03-01

Full Text Available New analysis of heat capacity data is presented for LuZnSn2 compound that takes into account anharmonic effects together with the existence of Einstein modes. 119mSn Mössbauer spectroscopy was used to monitor the hyperfine parameters at the two crystallographically inequivalent Sn sites in the studied compound. The problem of non-unique mathematical resonance spectrum description and the problem how to choose physically meaningful set of hyperfine parameters will be thoroughly discussed. Measured quadrupole interaction constants by 119mSn Mössbauer spectroscopy give estimations for Vzz component of electric field gradient tensor at both Sn sites in LuZnSn2.

Spectroscopic characterization and temporal dynamics of energy transfer process between Tm{sup 3+} -Ho{sup 3+} and Yb{sup 3+} -Tm{sup 3+} ions in LiYF{sub 4} and LiLuF{sub 4} crystals; Caracterizacao espectroscopica e dinamica temporal dos processos de transferencia de energia entre os ions Tm{sup 3+} -Ho{sup 3+} e Yb{sup 3+} -Tm{sup 3+} em cristais de LiYF{sub 4} and LiLuF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Tarelho, Luiz Vicente Gomes

2001-07-01

In this work, we perform spectroscopic studies to characterize the energy transfer processes occurring in rare-earth doped lithium fluoride systems, aiming the optimization of the population inversion of these media. Yb{sup 3+} ion was used in order to probe the electron-phonon coupling in LiYF{sub 4}, LiGdF{sub 4} and LiLuF{sub 4} matrices. In these systems it was obtained the average phononenergy, the vibronic transition probability and Huang-Rhys coupling constant. These parameters are dependent on the crystal host and the LiLuF{sub 4} system presents excluded correlation effects, an electronic repulsion that weakens the vibronic coupling. The Tm:Ho:LiYF{sub 4} system was studied under diode laser pumping at 796 nm, aiming the 2 {mu}m emission optimization. The ideal conditions of concentration and laser power were determined favouring the latter emission. Upconversion processes of two photons were identified besides the energy transfer among ions. The dynamic processes of luminescence of donors and acceptors allowed one to classify the energy transfer process as an energy transfer process assisted by fast diffusion among donors. The spectroscopic study of the Yb:Tm:LiYF{sub 4} allowed the determination of efficient non resonant transfer mechanisms between ({sup 2}F{sub 5/2}) Ytterbium level and ({sup 3}H{sub 5}) Thulium level, assisted by two phonon with hopping migration among donors ( Foerster-Burshtein model). The repopulation process of the Yb donor level is due to a cooperative sensitization between Yb-Tm pairs followed by an energy transfer process. (author)

Thermal stability of LiNaR2F8 compounds (R=Ho-Lu, Y)

International Nuclear Information System (INIS)

Fedorov, P.P.; Medvedeva, L.V.; Bondareva, O.S.; Sobolev, B.P.

1990-01-01

Monoclinic pseudorhombic compound mentioned in the title are investigated. It is determined, that the compounds are stable within temperature narrow range: Ho - 575-693 degC, Er - 566-712deg C, Tm - 560-710 deg C, Yb - less than 685 deg C, Y - 580-712 deg C. Triangulation of LiF-NaF-YF 3 system is carried out

High-gain polymer optical waveguide amplifiers based on core-shell NaYF4/NaLuF4: Yb3+, Er3+ NPs-PMMA covalent-linking nanocomposites

Science.gov (United States)

Zhang, Meiling; Zhang, Weiwei; Wang, Fei; Zhao, Dan; Qu, Chunyang; Wang, Xibin; Yi, Yunji; Cassan, Eric; Zhang, Daming

2016-11-01

Waveguide amplifiers have always been significant key components for optical communication. Unfortunately, the low concentration of rare earth ions doped in the host material and the inadequate optimization of the waveguide structure have been the common bottleneck limitations. Here, a novel material, NaYF4/NaLuF4: 20% Yb3+, 2% Er3+ nanoparticle-Polymeric Methyl Methacrylate covalent-linking nanocomposite, was synthesized. The concentrations of Er3+ and Yb3+ doping increased an order of magnitude. Under a 980 nm laser excitation, highly efficient emission at 1.53 μm was obtained. The characteristic parameters of the single mode waveguide were carefully designed and optimized by using a finite difference method. A formulized iteration method is presented for solving the rate equations and the propagation equations of the EYCDWA, and both the steady state behavior and the gain were numerically simulated. The optimal Er3+ and Yb3+ concentrations are 2.8 × 1026 m-3 and 2.8 × 1027 m-3, and the optimal waveguide length is 1.3 cm. Both theoretical and experimental results indicated that, for an input signal power of 0.1 mW and a pump power of 400 mW, a net gain of 15.1 dB at 1530 nm is demonstrated. This result is the highest gain ever reported in polymer-based waveguide amplifiers doped with inorganic Er3+-Yb3+ codoped nanocrystals.

Structural, electronic, optical and thermodynamic properties of cubic REGa{sub 3} (RE = Sc or Lu) compounds: Ab initio study

Energy Technology Data Exchange (ETDEWEB)

Murtaza, G., E-mail: murtaza@icp.edu.pk [Materials Modeling Laboratory, Department of Physics, Islamia College Peshawar (Pakistan); Gupta, S.K. [Department of Physics, Michigan Technological University, Houghton, MI 49931 (United States); Seddik, T. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Alahmed, Z.A. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Ahmed, R. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Khachai, H. [Physics Department, Djillali Liabes University of Sidi Bel-Abbes (Algeria); Jha, P.K. [Department of Physics, Maharaja Krishnakumarsinhji Bhavnagar University, Bhavnagar 364001 (India); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)

2014-06-01

Highlights: • REGa{sub 3} (RE = Sc or Lu) compounds are mechanical stabile. • Both ScGa{sub 3} and LuGa{sub 3} exhibit metallic behavior just like other REGa{sub 3} compounds. • Melting temperature T{sub m} (K) for ScGa{sub 3} and LuGa{sub 3} are 1244.2 and 1143.8. • High absorption observed in the visible energy region. • The present study would be helpful for future experimental/theoretical explorations. - Abstract: Structural, elastic, optoelectronic and thermodynamic properties of REGa{sub 3} (RE = Sc and Lu) compounds have been studied self consistently by employing state of the art full potential (FP) linearized (L) approach of augmented plane wave (APW) plus local orbitals method. Calculations were executed at the level of Perdew–Burke and Ernzerhof (PBE) parameterized generalized gradient approximation (GGA) for exchange correlation functional in addition to modified Becke–Johnson (mBJ) potential. Our obtained results of lattice parameters show reasonable agreement to the previously reported experimental and other theoretical studies. Analysis of the calculated band structure of ScGa{sub 3} and LuGa{sub 3} compounds demonstrates their metallic character. Moreover, a positive value of calculated Cauchy pressure, in addition to reflecting their ductile nature, endorses their metallic character as well. To understand optical behavior calculations related to the important optical parameters; real and imaginary parts of the dielectric function, reflectivity R(ω), refractive index n(ω) and electron energy-loss function L(ω) have also been performed. In the present work, thermodynamically properties are also investigated by employing lattice vibrations integrated in quasi harmonic Debye model. Obtained results of volume, heat capacity and Debye temperature as a function of temperature for both compounds, at different values of pressure, are found to be consistent. The calculated value of melting temperature for both compounds (ScGa{sub 3} and Lu

Pressure dependence of the Curie temperature in the Kondo lattice compound YbNiSn

Energy Technology Data Exchange (ETDEWEB)

Sparn, G; Thompson, J D [Los Alamos National Lab., NM (United States); Hamzic, A [Dept. of Physics, Zagreb (Yugoslavia)

1992-04-03

We have measured the magnetic susceptibility (2 K < T < 300 K) and the electrical resistivity under pressure (1.2 K < T < 300 K; p < 20 kbar) of the Kondo lattice compound YbNiSn, which may be considered as the ''hole'' analogue of the isostructural compound CeNiSn. In contrast with CeNiSn, YbNiSn does not show an energy gap at low temperatures but instead undergoes a magnetic phase transition at T{sub M} = 5.5 K. The magnetic state might be either a weakly ferromagnetic or a complex antiferromagnetic state. By applying pressure the room temperature resistance {rho}{sub RT} decreases, while T{sub M} increases. This behavior can be interpreted with respect to Doniach's Kondo necklace model as a decrease in the local exchange coupling constant J with increasing pressure, which reduces Kondo spin compensation and favors long-range magnetic order. These results show that the idea that YbNiSn is the hole counterpart to CeNiSn holds well for the properties such as dT{sub M}/dP and d{rho}{sub RT}/dP but that it fails in more detailed aspects, such as the origin of the energy gap formation. (orig.).

Magnetic anisotropy of pure and doped YbInCu sub 4 compounds at ambient and high pressures

CERN Document Server

Mushnikov, N V; Rozenfeld, E V; Yoshimura, K; Zhang, W; Yamada, M; Kageyama, H

2003-01-01

The susceptibility and high-field magnetization of single-crystalline Yb sub 1 sub - sub x Y sub x InCu sub 4 (x = 0, 0.2 and 0.3) samples have been measured for different field orientations at ambient and high pressures. The compounds with x = 0 and 0.2 undergo a first-order valence transition from the intermediate-valence state to the trivalent state on increasing either temperature or magnetic field. The magnetization and susceptibility of these compounds have appreciable anisotropy in both states. The magnetic phase diagram of Yb sub 1 sub - sub x Y sub x InCu sub 4 determined at ambient pressure is also anisotropic, which is explained by the crystal-field calculations for the free Yb ion in the high-temperature phase. Moreover, the low-temperature magnetization process for x = 0.2 and 0.3 has been measured in low fields under high pressure; it shows anisotropic ferromagnetic ordering.

Evidence for a magnetic moment at the Lu site of LuFe2

International Nuclear Information System (INIS)

Kasamatsu, Y.; Armitage, J.G.M.; Lord, J.S.; Riedi, P.C.; Fort, D.

1995-01-01

High pressure 175 Lu NMR measurements of LuFe 2 at 4.2 K suggest that Lu, like Y and Zr, carries a negative magnetic moment, in agreement with self-consistent energy band calculations. The observed spectrum is more complicated than would be expected for a Laves phase compound. ((orig.))

K-electron capture probability in 171Lu

International Nuclear Information System (INIS)

Mishra, N.R.; Vara Prasad, N.V.S.; Chandrasekhara Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

1999-01-01

The K-electron capture probability in the decay of 171 Lu to the 835.06 keV level of the daughter nucleus 171 Yb is measured to be 0.822 ± 0.027 involving two transitions, in agreement with the theoretical value 0.833. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos. (author)

Synthesis and magnetic structure of the YbMn{sub 2}Sb{sub 2} compound

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation)]. E-mail: morozkin@general.chem.msu.ru; Isnard, O. [Institute Laue-Langevin, 6 Rue J. Horowitz, 38042 Grenoble (France); Henry, P. [Institute Laue-Langevin, 6 Rue J. Horowitz, 38042 Grenoble (France); Granovsky, S. [Physics Department, Moscow State University, GSP-2, 119899 Moscow (Russian Federation); Nirmala, R. [Indian Institute of Science, Bangalore (India); Manfrinetti, P. [Dipartimento di Chimica, Universita di Genova, Via Dodecaneso 31, 16146 Genova (Italy)

2006-08-31

A neutron diffraction investigation has been carried out on the trigonal La{sub 2}O{sub 3}-type (hP5, space group P3-bar ml, No. 164; also CaAl{sub 2}Si{sub 2}-type) YbMn{sub 2}Sb{sub 2} intermetallic. A two-step synthesis route has been tried in this work, and successfully utilised to prepare single phase samples of this compound. This study shows that YbMn{sub 2}Sb{sub 2} presents antiferromagnetic ordering below 120K. The magnetic structure of this intermetallic consists of antiferromagnetically coupled magnetic moments of the manganese atoms, in the Mn1 (1/3, 2/3, Z{sub Mn}) and Mn2 (2/3, 1/3, 1-Z{sub Mn}) sites; the direction of magnetic moments of manganese atoms forming a {phi} and a {theta} angle, respectively with the X- and the Z-axis. At 4K the magnetic moment of the Mn1 atom is {mu}{sub Mn}=3.6(1) {mu}{sub B}, with {phi}=0{sup o} and {theta}=62(4){sup o}, whilst the Mn2 atom has a magnetic moment {mu}{sub Mn}=3.6(1) {mu}{sub B}, with {phi}=0{sup o} and {theta}=242(4){sup o}. On the other hand, in this compound no local moment was detected on the Yb site.

Growth and luminescent properties of Yb3+--doped oxide single crystals for scintillator application

International Nuclear Information System (INIS)

Yoshikawa, A.; Ogino, H.; Shim, J.B.; Nikl, M.; Solovieva, N.; Fukuda, T.

2004-01-01

Rod-shaped (Lu 1-x Yb x ) 3 Al 5 O 12 with x=0.05, 0.15, 0.30 and (Y 1-x Yb x )AlO 3 with x=0.05, 0.10, 0.30 single crystals were grown by the micro-pulling-down method. Edge-defined film-fed growth method was used to prepare (Y 0.9 Yb 0.1 )VO 4 crystal, while Ca 8 (La 1.98 Yb 0.02 )(PO 4 ) 6 O 2 crystal was grown by the Czochralski method. Luminescence of these crystals was studied with main attention paid to the charge transfer emission of Yb 3+ . Temperature tuned decay times in the time scale of units--tens of nanosecond was measured as a feature possibly interesting for an application in scintillation detectors in positron emission tomography

Structural, electronic and magnetic properties of layered REB{sub 2}C compounds (RE=Dy, Tm, Lu)

Energy Technology Data Exchange (ETDEWEB)

Babizhetskyy, Volodymyr, E-mail: v.babizhetskyy@googlemail.com [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Department of Inorganic Chemistry, Ivan Franko National University of L' viv, Kyryla and Mefodiya Str. 6, UA-79005 Lviv (Ukraine); Simon, Arndt; Hoch, Constantin [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Hiebl, Kurt [Arbeitsgruppe Neue Materialien, Universitaet Wien, Waehringerstrasse 42, A-1090 Wien (Austria); Le Polles, Laurent [Sciences Chimiques de Rennes, UMR 6226 CNRS, Ecole Nationale Superieure de Chimie de Rennes, Universite de Rennes 1, Avenue du General Leclerc, F-35042 Rennes Cedex (France); Gautier, Regis, E-mail: rgautier@ensc-rennes.fr [Sciences Chimiques de Rennes, UMR 6226 CNRS, Ecole Nationale Superieure de Chimie de Rennes, Universite de Rennes 1, Avenue du General Leclerc, F-35042 Rennes Cedex (France); Halet, Jean-Francois, E-mail: halet@univ-rennes1.fr [Sciences Chimiques de Rennes, UMR 6226 CNRS, Ecole Nationale Superieure de Chimie de Rennes, Universite de Rennes 1, Avenue du General Leclerc, F-35042 Rennes Cedex (France)

2012-07-15

The crystal structure of LuB{sub 2}C has been determined from single crystal and powder X-ray diffraction data. It crystallizes in the orthorhombic space group Pbam (a=6.7429(1) A, b=6.7341(1) A, c=3.5890(1) A, Z=4, R1=0.024 (wR2=0.059) for 436 reflections with I{sub o}>2{sigma}(I{sub o})). The compounds REB{sub 2}C (RE=Y, Tb-Lu) are isotypic. The boron and carbon atoms form infinite, planar two-dimensional nets which alternate with sheets of rare-earth metal atoms. Inside the nonmetal atom nets, a coloring with fused B{sub 2}C{sub 2} rhombuses and B{sub 5}C{sub 2} heptagons is proposed, supported by NMR experiments and density functional theory calculations. The calculated density of states of LuB{sub 2}C indicates this compound to be metallic. The magnetic properties of the isotypic compound TmB{sub 2}C, has been measured in the temperature range 2 K3 T a metamagnetic transition is encountered. The temperature dependence of the electrical resistivity proves the metallic character of the TmB{sub 2}C compound as well as the AFM ordering. - Graphical abstract: The crystal structure of LuB{sub 2}C has been determined from single crystal and powder X-ray diffraction data. It crystallizes in the orthorhombic space group Pbam. The compounds REB{sub 2}C (RE=Y, Tb-Lu) are isotypic. The boron and carbon atoms form infinite, planar two-dimensional nets which alternate with sheets of rare-earth metal atoms. Inside the nonmetal atom nets, a coloring with fused B{sub 2}C{sub 2} rhombuses and B{sub 5}C{sub 2} heptagons is proposed, supported by NMR experiments and density functional theory calculations. The magnetic properties of the isotypic compound TmB{sub 2}C, has been measured in the temperature range 2 K

Ultrasmall, water dispersible, TWEEN80 modified Yb:Er:NaGd(WO4)2 nanoparticles with record upconversion ratiometric thermal sensitivity and their internalization by mesenchymal stem cells

Science.gov (United States)

Cascales, Concepción; Paíno, Carlos L.; Bazán, Eulalia; Zaldo, Carlos

2017-05-01

This work presents the synthesis by coprecipitation of diamond shaped Yb:Er:NaGd(WO4)2 crystalline nanoparticles (NPs) with diagonal dimensions in the 5-7 nm × 10-12 nm range which have been modified with TWEEN80 for their dispersion in water, and their interaction with mesenchymal stem cells (MSCs) proposed as cellular NP vehicles. These NPs belong to a large family of tetragonal Yb:Er:NaT(XO4)2 (T = Y, La, Gd, Lu; X = Mo, W) compounds with green (2H11/2 + 4S3/2 → 4I15/2) Er-related upconversion (UC) efficiency comparable to that of Yb:Er:β-NaYF4 reference compound, but with a ratiometric thermal sensitivity (S) 2.5-3.5 times larger than that of the fluoride. At the temperature range of interest for biomedical applications (˜293-317 K/20-44 °C) S = 108-118 × 10-4 K-1 for 20 at%Yb:5 at%Er:NaGd(WO4)2 NPs, being the largest values so far reported using the 2H11/2/4S3/2 Er intensity ratiometric method. Cultured MSCs, incubated with these water NP emulsions, internalize and accumulate the NPs enclosed in endosomes/lysosomes. Incubations with up to 10 μg of NPs per ml of culture medium maintain cellular metabolism at 72 h. A thermal assisted excitation path is discussed as responsible for the UC behavior of Yb:Er:NaT(XO4)2 compounds.

Low-temperature thermal properties of yttrium and lutetium dodecaborides

International Nuclear Information System (INIS)

Czopnik, A; Shitsevalova, N; Pluzhnikov, V; Krivchikov, A; Paderno, Yu; Onuki, Y

2005-01-01

The heat capacity (C p ) and dilatation (α) of YB 12 and LuB 12 are studied. C p of the zone-melted YB 12 tricrystal is measured in the range 2.5-70 K, of the zone-melted LuB 12 single crystal in the range 0.6-70 K, and of the LuB 12 powder sample in the range 4.3-300 K; α of the zone-melted YB 12 tricrystal and LuB 12 single crystals is measured in the range 5-200 K. At low temperatures a negative thermal expansion (NTE) is revealed for both compounds: for YB 12 at 50-70 K, for LuB 12 at 10-20 K and 60-130 K. Their high-temperature NTE is a consequence of nearly non-interacting freely oscillating metal ions (Einstein oscillators) in cavities of a simple cubic rigid Debye lattice formed by B 12 cage units. The Einstein temperatures are ∼254 and ∼164 K, and the Debye temperatures are ∼1040 K and ∼1190 K for YB 12 and LuB 12 respectively. The LuB 12 low-temperature NTE is connected with an induced low-energy defect mode. The YB 12 superconducting transition has not been detected up to 2.5 K

The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

Energy Technology Data Exchange (ETDEWEB)

Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

2008-02-15

The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

Characterization of an Yb:LuVO{sub 4} single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Paszkowicz, W., E-mail: paszk@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, PL-02668 Warsaw (Poland); Romanowski, P.; Bak-Misiuk, J. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, PL-02668 Warsaw (Poland); Wierzchowski, W. [Institute of Electronic Materials Technology, Wolczynska 133, PL-01919 Warsaw (Poland); Wieteska, K. [Institute of Atomic Energy POLATOM, PL-05400 Otwock-Swierk (Poland); Graeff, W. [HASYLAB at DESY, Notkestr. 85, D-22603 Hamburg (Germany); Iwanowski, R.J. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, PL-02668 Warsaw (Poland); Heinonen, M.H. [Laboratory of Materials Science, Department of Physics, University of Turku, Vesilinnantie 5, FI-20014, Turku (Finland); Ermakova, O. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, PL-02668 Warsaw (Poland); Dabkowska, H. [Department of Physics, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)

2011-10-15

Knowledge on the defect and electronic structure allows for improved modeling of material properties. A short literature review has shown that the information on defect structure of rare earth orthovanadate single crystals is limited. In this paper, defect and electronic structure of a needle-shaped Yb:LuVO{sub 4} single crystal grown by the slow cooling method have been studied by means of X-ray diffraction topography employing white synchrotron beam, high-resolution diffraction (HRD) and photoelectron spectroscopy (XPS) techniques. Topographic investigations show that the crystal is composed of two blocks disoriented by about 1.5{sup o} and separated by a narrow deformed region. Some contrasts observed within the crystal volume may be attributed to glide bands and sector boundaries. The contrasts appearing in the vicinity of the surface may be interpreted as due to the presence of small inclusions. The HRD study indicates, in particular, that among point defects, the vacancy type defects dominate and that the density of other defects is small in comparison. The XPS measurements enabled, despite highly insulating properties of the studied crystal, an analysis of its bulk electronic structure, including the main core-levels (O 1s, V 2p, Lu 4f) as well as the valence band range.

Phase relations in Ca(Sr)MoO4-Ln2(NoO4)3 systems (Ln = Pr-Lu)

International Nuclear Information System (INIS)

Vakalyuk, V.V.; Evdokimov, A.A.; Berezina, T.A.

1982-01-01

Using the methods of X-ray phase and differential thermal analyses phase ratios in the systems Ca(Sr)MoO 4 -Ln 2 (MoO 4 ) 3 at Ln=Pr-Lu are studied and phase diagrams of the systems CaMoO 4 -Ln 2 (MoO 4 ) 3 , for Ln=Nd, Gd, Yb and SrMoO 4 -Sm 2 (MoO 4 ) 3 are built. It is shown that phase ratios in the systems are similar for the following groups of rare earths: Pr-Sm, Eu-Tb, Ho-Lu. In the first group of systems ordered phase over all subsolidus region are formed, in the second one - ordered phases with scheelite-like structure and wide regions of homogeneity on the basis of Ca(Sr)MoO 4 are formed above the temperature of polymorphous transformation of rare earth molybdates, for the third group of systems intermediate compounds are not detected

Effective tuning of the ratio of red to green emission of Ho"3"+ ions in single LiLuF_4 microparticle via codoping Ce"3"+ ions

International Nuclear Information System (INIS)

Gao, Wei; Dong, Jun; Liu, Jihong; Yan, Xuewen

2016-01-01

Yb"3"+/Ho"3"+ codoped LiLuF_4 microparticles have been successfully prepared via a facile hydrothermal method. The crystal phase and morphology of LiLuF_4 microparticles were inspected by x-ray diffraction and scanning electron microscope, respectively. The upconversion emission of single LiLuF_4: Yb"3"+/Ho"3"+ microparticle was carefully studied by a confocal microscopy setup under NIR 980 nm excitation. With the increase of Ce"3"+ ion concentrations of 12%, the ratio of red to green emission of the Ho"3"+ ions of single LiLuF_4 microparticle was boosted about 17-fold, and the output colors were tuned from green to red, which is due to the two efficient cross-relaxation between Ho"3"+ and Ce"3"+ ions enhances the red and suppresses the green in the emission processes. To investigate the optical properties of the single microparticle or nanoparticle through the confocal microscopy setup can effectively avoid the influence of surrounding particle or environment, and could provide more precise information for better exploring the emission mechanisms of rare earth ions. The tunable upconversion emission of Ho"3"+ in single LiLuF_4 microparticle in this work will have great potential applications in the micro optoelectronic devices and color display applications. - Highlights: • The optical properties of the single LiLuF4: Yb3+/Ho3+/Ce3+ microparticle were studied. • The output colors of single LiLuF4 microparticle were tuned from green to red. • The upconversion mechanisms between Ho3+ and Ce3+ ions were discussed based on emission spectrum.

Development of LuAG-based scintillator crystals - A review

Czech Academy of Sciences Publication Activity Database

Nikl, Martin; Yoshikawa, A.; Kamada, K.; Nejezchleb, K.; Stanek, C.R.; Mareš, Jiří A.; Blazek, K.

2013-01-01

Roč. 59, č. 2 (2013), s. 47-72 ISSN 0960-8974 R&D Projects: GA ČR GAP204/12/0805; GA AV ČR KAN300100802 Grant - others:GA AV(CZ) M100100910 Institutional support: RVO:68378271 Keywords : garnet * scintillator * Lu 3 Al 5 O 12 * Ce 3+ * Pr 3+ * Sc 3+ * Yb 3+ Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.476, year: 2013

Properties of the divalent-Yb compound YbAu{sub 2}Si{sub 2} under extreme conditions

Energy Technology Data Exchange (ETDEWEB)

Kaštil, J.; Míšek, M.; Kamarád, J.; Arnold, Z. [Institute of Physics AS CR, v.v.i., Na Slovance 1999/2, 182 21 Prague 8 (Czech Republic); Vlášková, K. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Prchal, J., E-mail: prchal@karlov.mff.cuni.cz [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Diviš, M.; Doležal, P.; Prokleška, J.; Valenta, J.; Fikáček, J.; Rudajevová, A.; Kriegner, D. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 12116 Prague 2 (Czech Republic)

2017-01-15

Polycrystalline YbAu{sub 2}Si{sub 2} has been prepared by arc melting and a non-standard anisotropic thermal expansion is observed at low temperatures. A non-magnetic Yb{sup 2+} valence state is derived from magnetization, magnetic-susceptibility, heat-capacity and electrical-conductivity measurements in the temperature range from 0.3 to 300 K and at external pressures up to 3.2 GPa. By both experimental and theoretical investigations, YbAu{sub 2}Si{sub 2} is confirmed to be a system with a weak electron-electron correlations and a small electron-phonon interaction. Application of hydrostatic pressure does not reveal any change of state in the range of applied pressures.

Structural, electronic and elastic properties of heavy fermion YbRh2 Laves phase compound

Science.gov (United States)

Pawar, Harsha; Shugani, Mani; Aynyas, Mahendra; Sanyal, Sankar P.

2018-05-01

The structural, electronic and elastic properties of YbRh2 Laves phase intermetallic compound which crystallize in cubic (MgCu2-type) structure have been investigated using ab-initio full potential linearized augmented plane wave (FP- LAPW) method with LDA and LDA+U approximation. The calculated ground state properties such as lattice parameter (a0), bulk modulus (B) and its pressure derivative (B') are in good agreement with available experimental and theoretical data. The electronic properties are analyzed from band structures and density of states. Elastic constants are predicted first time for this compound which obeys the stability criteria for cubic system.

Effects of Lu and Tm Doping on Thermoelectric Properties of Bi2Te3 Compound

Science.gov (United States)

Yaprintsev, Maxim; Lyubushkin, Roman; Soklakova, Oxana; Ivanov, Oleg

2018-02-01

The Bi2Te3, Bi1.9Lu0.1Te3 and Bi1.9Tm0.1Te3 thermoelectrics of n-type conductivity have been prepared by the microwave-solvothermal method and spark plasma sintering. These compounds behave as degenerate semiconductors from room temperature up to temperature T d ≈ 470 K. Within this temperature range the temperature behavior of the specific electrical resistivity is due to the temperature changes of electron mobility determined by acoustic and optical phonon scattering. Above T d, an onset of intrinsic conductivity takes place when electrons and holes are present. At the Lu and Tm doping, the Seebeck coefficient increases, while the specific electrical resistivity and total thermal conductivity decrease within the temperature 290-630 K range. The increase of the electrical resistivity is related to the increase of electron concentration since the Tm and Lu atoms are donor centres in the Bi2Te3 lattice. The increase of the density-of-state effective mass for conduction band can be responsible for the increase of the Seebeck coefficient. The decrease of the total thermal conductivity in doped Bi2Te3 is attributed to point defects like the antisite defects and Lu or Tm atoms substituting for the Bi sites. In addition, reducing the electron thermal conductivity due to forming a narrow impurity (Lu or Tm) band having high and sharp density-of-states near the Fermi level can effectively decrease the total thermal conductivity. The thermoelectric figure-of-merit is enhanced from ˜ 0.4 for undoped Bi2Te3 up to ˜ 0.7 for Bi1.9Tm0.1Te3 and ˜ 0.9 for Bi1.9Lu0.1Te3.

High-resolution x-ray diffraction study of the heavy-fermion compound YbBiPt

Science.gov (United States)

Ueland, B. G.; Saunders, S. M.; Bud'Ko, S. L.; Schmiedeshoff, G. M.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

YbBiPt is a heavy-fermion compound possessing significant short-range antiferromagnetic correlations below T* = 0 . 7 K, fragile antiferromagnetic order below TN = 0 . 4 K, a Kondo temperature of TK ~ 1 K, and crystalline-electric-field splitting (CEF) on the order of E /kB = 1 - 10 K. Its lattice is face-centered cubic at ambient temperature, but certain data, particularly those from studies aimed at determining the CEF level scheme, suggest that the lattice distorts at lower temperature. Here, we present results from high-energy x-ray diffraction experiments which show that, within our experimental resolution of ~ 6 - 10 ×10-5 Å, no structural phase transition occurs between 1 . 5 and 50 K. Despite this result, we demonstrate that the compound's thermal expansion may be modeled using CEF level schemes appropriate for Yb3+ residing on a site with either cubic or less than cubic point symmetry. Work at the Ames Laboratory was supported by the US DOE, BES, DMSE, under Contract No. DE-AC02-07CH11358. Work at Occidental College was supported by the NSF under DMR-1408598. This research used resources at the Advanced Photon Source a US DOE, Office of Science, User Facility.

Novel Sr{sub 2}LuF{sub 7}–SiO{sub 2} nano-glass-ceramics: Structure and up-conversion luminescence

Energy Technology Data Exchange (ETDEWEB)

Yanes, A.C.; Castillo, J. del, E-mail: fjvargas@ull.edu.es; Luis, D.; Puentes, J.

2016-02-15

Novel transparent nano-glass-ceramics comprising RE-doped Sr{sub 2}LuF{sub 7} nanocrystals have been obtained by thermal treatment of precursor sol–gel glasses. The precipitated Sr{sub 2}LuF{sub 7} nanocrystals with sizes from 4.5 to 11.5 nm, confirmed by X-Ray Diffraction and Transmission Electron Microscopy images, show a cubic phase structure. The luminescent features of Eu{sup 3+} ions, used as structural probes, evidence the distribution of RE ions into the fluoride nanocrystals. Under 980 nm laser excitation, intense UV, vis and NIR up-conversion emissions were observed and studied in Yb{sup 3+}–Tm{sup 3+}, Yb{sup 3+}–Er{sup 3+} and Yb{sup 3+}–Ho{sup 3+} co-doped nano-glass-ceramics. These results suggest considering these nano-glass-ceramics for potential optical applications as high efficient UV up-conversion materials in UV solid state lasers, infrared tuneable phosphors and photonic integrated devices. - Highlights: • Novel sol-gel glass-ceramics with RE{sup 3+}-Sr{sub 2}LuF{sub 7} doped nanocrystals were obtained. • Eu{sup 3+} probe ion was used to distinguish between amorphous and crystalline environments. • The incorporation of an important fraction of RE ions into nanocrystals was confirmed. • Under 980 nm excitation, intense UV-vis-NIR up-conversion emissions were observed.

Multicolor upconversion emission of dispersed ultrasmall cubic Sr2LuF7 nanocrystals synthesized by a solvothermal process

International Nuclear Information System (INIS)

Gong, Lunjun; Ma, Mo; Xu, Changfu; Li, Xujun; Wang, Suiping; Lin, Jianguo; Yang, Qibin

2013-01-01

Lanthanide (Ln 3+ ) doped Sr 2 LuF 7 (Ln 3+ =Er 3+ /Tm 3+ /Yb 3+ ) nanocrystals (NCs) were synthesized via a solvothermal process using oleate as stabilizing agent. The as-synthesized NCs with a mean diameter of sub-20 nm can be well dispersed in cyclohexane and show a pure cubic phase structure with space group Fm3 ¯ m. Following appropriate lanthanide ion doping, the NCs show intense red, green, blue and white-color upconversion emission (UC) under the excitation of a 980 nm laser. Predominant near-infrared UC can also be obtained in the Yb 3+ /Tm 3+ doped Sr 2 LuF 7 NCs. The energy transfer UC mechanisms for the fluorescent intensity were also investigated. The desirable property of the ultrasmall dispersed NCs makes them promising materials for the applications in miniaturized solid-state light sources, multicolor three-dimensional display devices and fluorescent labels for biomedical imaging. - Highlights: ► Cubic-structure (Fm3 ¯ m) Sr 2 LuF 7 nanocrystals were synthesized for the first time. ► Nanocrystals (sub-20 nm) with cubic or spherical shape can be well dispersed. ► By doping properly, the nanocrystals show intense multicolor upconversion. ► Predominant near-infrared upconversion can be obtained in Sr 2 LuF 7 nanocrystals. ► Upconversion mechanism for the fluorescent intensity is mainly energy transfer.

Effective tuning of the ratio of red to green emission of Ho{sup 3+} ions in single LiLuF{sub 4} microparticle via codoping Ce{sup 3+} ions

Energy Technology Data Exchange (ETDEWEB)

Gao, Wei, E-mail: gaowei@xupt.edu.cn; Dong, Jun; Liu, Jihong; Yan, Xuewen

2016-09-15

Yb{sup 3+}/Ho{sup 3+} codoped LiLuF{sub 4} microparticles have been successfully prepared via a facile hydrothermal method. The crystal phase and morphology of LiLuF{sub 4} microparticles were inspected by x-ray diffraction and scanning electron microscope, respectively. The upconversion emission of single LiLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} microparticle was carefully studied by a confocal microscopy setup under NIR 980 nm excitation. With the increase of Ce{sup 3+} ion concentrations of 12%, the ratio of red to green emission of the Ho{sup 3+} ions of single LiLuF{sub 4} microparticle was boosted about 17-fold, and the output colors were tuned from green to red, which is due to the two efficient cross-relaxation between Ho{sup 3+} and Ce{sup 3+} ions enhances the red and suppresses the green in the emission processes. To investigate the optical properties of the single microparticle or nanoparticle through the confocal microscopy setup can effectively avoid the influence of surrounding particle or environment, and could provide more precise information for better exploring the emission mechanisms of rare earth ions. The tunable upconversion emission of Ho{sup 3+} in single LiLuF{sub 4} microparticle in this work will have great potential applications in the micro optoelectronic devices and color display applications. - Highlights: • The optical properties of the single LiLuF4: Yb3+/Ho3+/Ce3+ microparticle were studied. • The output colors of single LiLuF4 microparticle were tuned from green to red. • The upconversion mechanisms between Ho3+ and Ce3+ ions were discussed based on emission spectrum.

Identification of 5g and 6g terms and revised ionization energies in the Yb II 4f14nl isoelectronic sequence

International Nuclear Information System (INIS)

Sugar, J.; Kaufman, V.

1979-01-01

The 5f-5g transitions in Lu III through Os VIII and the 5f-6g transitions in Hf IV through W VI were identified and used to redetermine the ionization energies of Yb II, Lu III, W VI, Re VII, and Os VIII. Complete line-lists and energy levels are given for the one-electron spectra Hf IV, W VI and Os VIII

Yb5Ni4Sn10 and Yb7Ni4Sn13: New polar intermetallics with 3D framework structures

International Nuclear Information System (INIS)

Lei Xiaowu; Sun Zhongming; Li Longhua; Zhong Guohua; Hu Chunli; Mao Jianggao

2010-01-01

The title compounds have been obtained by solid state reactions of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. Yb 5 Ni 4 Sn 10 adopts the Sc 5 Co 4 Si 10 structure type and crystallizes in the tetragonal space group P4/mbm (No. 127) with cell parameters of a=13.785(4) A, c=4.492 (2) A, V=853.7(5) A 3 , and Z=2. Yb 7 Ni 4 Sn 13 is isostructural with Yb 7 Co 4 InGe 12 and crystallizes in the tetragonal space group P4/m (No. 83) with cell parameters of a=11.1429(6) A, c=4.5318(4) A, V=562.69(7) A 3 , and Z=1. Both structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are occupied by the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic. These results are in agreement with those from temperature-dependent resistivity and magnetic susceptibility measurements. - Graphical abstract: Two new ytterbium nickel stannides, namely, Yb 5 Ni 4 Sn 10 and Yb 7 Ni 4 Sn 13 , have been synthesized and structurally characterized by single-crystal X-ray diffraction studies. Both their structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are situated by all the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic, which are in accordance with the results from temperature-dependent resistivity and magnetic susceptibility measurements.

Identification of 5g and 6g terms and revised ionization energies in the Yb II 4f/sup 14/nl isoelectronic sequence

Energy Technology Data Exchange (ETDEWEB)

Sugar, J.; Kaufman, V.

1979-01-01

The 5f-5g transitions in Lu III through Os VIII and the 5f-6g transitions in Hf IV through W VI were identified and used to redetermine the ionization energies of Yb II, Lu III, W VI, Re VII, and Os VIII. Complete line-lists and energy levels are given for the one-electron spectra Hf IV, W VI and Os VIII.

Thermodynamic description of the Al-Cu-Yb ternary system supported by first-principles calculations

Directory of Open Access Journals (Sweden)

Huang G.

2016-01-01

Full Text Available Phase relationships of the ternary Al-Cu-Yb system have been assessed using a combination of CALPHAD method and first principles calculations. A self-consistent thermodynamic parameter was established based on the experimental and theoretical information. Most of the binary intermetallic phases, except Al3Yb, Al2Yb, Cu2Yb and Cu5Yb, were assumed to be zero solubility in the ternary system. Based on the experimental data, eight ternary intermetallic compounds were taken into consideration in this system. Among them, three were treated as line compounds with large homogeneity ranges for Al and Cu. The others were treated as stoichiometric compounds. The calculated phase diagrams were in agreement with available experimental and theoretical data.

Synthesis and characterisation of YbPdSb

Energy Technology Data Exchange (ETDEWEB)

Haines, Charles R.S.; Brown, Philip A.C.; Grosche, Friedrich M. [Department of Physics, Cavendish Laboratory, University of Cambridge (United Kingdom)

2016-07-01

The intermetallic compound YbPdSb can form in two structures: the low temperature (LT) half-Heusler phase, in which the Yb atoms form a frustrated fcc structure, and the high temperature (HT) Pnma modification. We have prepared phase pure samples of both structures and report resistivity, magnetisation and heat capacity measurements on both. The LT phase is a Kondo lattice system showing large-moment Curie-Weiss paramagnet behaviour without any phase transition anomalies down to the lowest temperatures measured. The resistivity is rather insensitive to temperature from room temperature down to ∝50 K where it decreases steeply with further cooling. By contrast, in the HT phase the magnetic susceptibility displays weak temperature dependence and the resistivity falls with decreasing temperature in the way expected of a weakly correlated metal. These findings suggest that in contrast to the electronic state in the LT structure, the 4f-shell of Yb is completely filled in the HT structure of YbPdSb, presenting an interesting opportunity to study the interplay between lattice and electronic structure within the same compound.

Superconductivity in the ternary rare-earth (Y, La, and Lu) compounds RPd2Si2 and RRh2Si2

NARCIS (Netherlands)

Palstra, T.T.M.; Lu, G.; Menovsky, A.A.; Nieuwenhuys, G.J.; Kes, P.H.; Mydosh, J.A.

1986-01-01

We have investigated the superconducting and metallurgical properties of the ternary compounds RPd2Si2 and RRh2Si2 with R = Y, La, and Lu. All RPd2Si2 compounds and LaRh2Si2 were found to be type-I superconductors below 1 K. A detailed metallurgical analysis shows that segregation of second phases

Preparation and radiopharmaceutical control of 169Yb EDTA an agent for kidney function and scintigraphy

International Nuclear Information System (INIS)

Gulbaba, G.; Ozker; Tomek, F.

1976-01-01

169 Yb was produced by thermal neutron irradiation of Yb 2 O 3 in 1 MW research reactor at Cekmece Nuclear Research Center. 169 Yb-EDTA complex was then prepared with a sodium salt of EDTA. Radionuclidic and radiochemical purities of the compound were determined by gama spectral analysis and radiochromatography-electrophoresis following preparation. Ionic Yb(III) which accumulates at bone and liver was not observed on the radiochromatographic and electrophoretic analysis of the final compound. There was no separation of the label for two months of examination in order to determine stability of the compound. In conclusion, the labeled compound has been prepared for use in the external scanning of kidney and determining the glomerular filtration rate. The label appears to be firmly bound so that the agent can be stored for a reasonably long period as 31 days half-life of 169 Yb permits. Administration of the compound is safe from the stand point of radiation dose since a 30 micro-Ci 169 Yb-EDTA for a glomerular filtration study delivers no more than 0.4 mrad whole-body and 5 mrad kidney dose. (author)

Water-stable NaLuF4-based upconversion nanophosphors with long-term validity for multimodal lymphatic imaging.

Science.gov (United States)

Zhou, Jing; Zhu, Xingjun; Chen, Min; Sun, Yun; Li, Fuyou

2012-09-01

Multimodal imaging is rapidly becoming an important tool for biomedical applications because it can compensate for the deficiencies of individual imaging modalities. Herein, multifunctional NaLuF(4)-based upconversion nanoparticles (Lu-UCNPs) were synthesized though a facile one-step microemulsion method under ambient condition. The doping of lanthanide ions (Gd(3+), Yb(3+) and Er(3+)/Tm(3+)) endows the Lu-UCNPs with high T(1)-enhancement, bright upconversion luminescence (UCL) emissions, and excellent X-ray absorption coefficient. Moreover, the as-prepared Lu-UCNPs are stable in water for more than six months, due to the protection of sodium glutamate and diethylene triamine pentacetate acid (DTPA) coordinating ligands on the surface. Lu-UCNPs have been successfully applied to the trimodal CT/MR/UCL lymphatic imaging on the modal of small animals. It is worth noting that Lu-UCNPs could be used for imaging even after preserving for over six months. In vitro transmission electron microscope (TEM), methyl thiazolyl tetrazolium (MTT) assay and histological analysis demonstrated that Lu-UCNPs exhibited low toxicity on living systems. Therefore, Lu-UCNPs could be multimodal agents for CT/MR/UCL imaging, and the concept can be served as a platform technology for the next-generation of probes for multimodal imaging. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vaporization thermodynamics of Pd-rich intermediate phases in the Pd–Yb system

Energy Technology Data Exchange (ETDEWEB)

Ciccioli, A., E-mail: andrea.ciccioli@uniroma1.it [Dipartimento di Chimica, Sapienza Università di Roma, p.le Aldo Moro 5, 00185 Roma (Italy); Balducci, G.; Gigli, G. [Dipartimento di Chimica, Sapienza Università di Roma, p.le Aldo Moro 5, 00185 Roma (Italy); Provino, A. [Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, via Dodecaneso 31, 16146 Genova (Italy); Istituto SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Palenzona, A. [Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, via Dodecaneso 31, 16146 Genova (Italy); Manfrinetti, P. [Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, via Dodecaneso 31, 16146 Genova (Italy); Istituto SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy)

2016-02-20

Highlights: • Vaporization equilibria of Pd–Yb intermediate phases investigated by effusion techniques. • Heats of formation of Pd–Yb compounds determined from decomposition/atomization enthalpies. • Phase diagram of the Pd–Yb system re-drawn. • Influence of the Yb valence state on the thermodynamic properties observed. - Abstract: The vaporization thermodynamics of several intermediate phases in the Pd–Yb system was investigated by means of vaporization experiments performed under Knudsen conditions (KEML, Knudsen Effusion Mass Loss). The following thermal decomposition processes were studied in the overall temperature range 819–1240 K and their enthalpy changes determined: 4 PdYb(s) = Pd{sub 4}Yb{sub 3}(s) + Yb(g); 5/3 Pd{sub 4}Yb{sub 3}(s) = 4/3 Pd{sub 5}Yb{sub 3}(s) + Yb(g); 21/13 Pd{sub 5}Yb{sub 3}(s) = 5/13 Pd{sub 21}Yb{sub 10}(s) + Yb(g); 1/3 Pd{sub 21}Yb{sub 10}(s) = 21/9 Pd{sub 3}Yb(s) + Yb(g). Additional measurements were performed by KEMS (Knudsen Effusion Mass Spectrometry) on a Pd-rich two-phase sample, which allowed to detect both Yb(g) and Pd(g) in the vapor phase and to determine the atomization enthalpy of the Pd{sub 3}Yb phase (Pd-rich composition boundary, Pd{sub 3.08}Yb{sub 0.92}): Pd{sub 3.08}Yb{sub 0.92}(s) = 0.92 Yb(g) + 3.08 Pd(g). The enthalpy of formation of this compound was thereafter determined as −68 ± 2 kJ/mol at. and, by combining this value with the decomposition enthalpies derived by KEML, the enthalpies of formation of the studied Pd–Yb intermediate phases were evaluated (kJ/mol at.): −75 ± 4 (Pd{sub 21}Yb{sub 10}), −75 ± 3 (Pd{sub 5}Yb{sub 3}), −73 ± 3 (Pd{sub 4}Yb{sub 3}), and −66 ± 3 (PdYb). A modified version of the Pd–Yb phase diagram is also reported, re-drawn on the basis of literature data and of new experimental information recently become available.

Characterization of the electronic properties of YB{sub 12}, ZrB{sub 12}, and LuB{sub 12} using {sup 11}B NMR and first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Jaeger, B [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringer Strasse 42, 1090 Vienna (Austria); Paluch, S [Institute for Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wroclaw (Poland); Zogal, O J [Institute for Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wroclaw (Poland); Wolf, W [Materials Design s. a. r. l., 44, avenue F.-A. Bartholdi, 72000 Le Mans (France); Herzig, P [Institut fuer Physikalische Chemie, Universitaet Wien, Waehringer Strasse 42, 1090 Vienna (Austria); Filippov, V B [Institute for Problems of Materials Science, Academy of Sciences of Ukraine, 3 Krzhyzhanovsky street, 03680 Kiev, Ukraine (Ukraine); Shitsevalova, N [Institute for Problems of Materials Science, Academy of Sciences of Ukraine, 3 Krzhyzhanovsky street, 03680 Kiev, Ukraine (Ukraine); Paderno, Y [Institute for Problems of Materials Science, Academy of Sciences of Ukraine, 3 Krzhyzhanovsky street, 03680 Kiev, Ukraine (Ukraine)

2006-03-01

Three metallic dodecaborides, YB{sub 12}, ZrB{sub 12} and LuB{sub 12}, have been investigated by electric-field gradient (EFG) measurements at the boron sites using the {sup 11}B nuclear magnetic resonance (NMR) technique and by performing first-principles calculations. The NMR powder spectra reveal patterns typical for a completely asymmetric EFG tensor, i.e., an {eta} parameter close to unity. The absolute values of V{sub zz} (the largest component of the EFG) are determined from the spectra and they range between 11 x 10{sup 20} V m{sup -2} and 11.6 x 10{sup 20} V m{sup -2} with an uncertainty of 0.8 x 10{sup 20} V m{sup -2}, being in very good agreement with the first-principles results. In addition the electronic structure and chemical bonding are analysed from partial densities of states and electron densities.

Parameters of thermoelectric power and electronic structure of Yb-based compounds of YbM2X2(M=Fe,Co,Ni,Cu; X=Si,Ge) type

International Nuclear Information System (INIS)

Levin, E.M.; Kuzhel', B.S.

1990-01-01

Thermoelectric power of Yb-based intermetallic alloys YbM 2 Si 2 (M-Co,Ni,Cu) and YbM 2 Ge 2 (M=Fe,Co,Ni) have been investigated and found to have anomalous low-temperature peaks conditioned by intermediate Yb valency. Calculation of electronic structure parameters performed in frames of the localized Fermi-liquid model using experimental data on the thermoelectric power is in good agreement with results of YbCu 2 Si 2 band structure calculation based on the experimental value of the electronic heat capacity with regard for the (2J+1) - fold Yb 2+ degeneration

Study of chromites YbMIICr2O5,5 (MII - Mg, Ca, Sr, Ba by X-ray diffraction

Directory of Open Access Journals (Sweden)

B. Kasenov

2012-03-01

Full Text Available Compounds of composition YbMeMnFeO5,5 (Me – Mg, Ca, Sr, Ba are synthesized from Yb2O3, , Cr2O3 and MgCO3, CaCO3, SrCO3, BaCO3 by solid phase method. X-ray powder diffraction showed that the compound YbMgCr2O5,5, YbCaCr2O5,5, YbSrCr2O5,5, YbBaCr2O5,5 crystallizes in the tetragonal crystal system.

Cross sections of (n, α) reactions on rare-earth elements from Tb through Lu at En ∼ 14 MeV

International Nuclear Information System (INIS)

Kadenko, A.O.; Gorbachenko, O.M.; Primenko, G.I.; Kadenko, I.M.; Plujko, V.A.

2012-01-01

The cross sections of the neutron reactions at E n = 14.6 MeV on the isotopes of Tb-159, Dy-164, Er-168, Er-170, Yb-174, Yb-176, Lu-175, and Lu-176 with alpha-particle emission were studied by the use of new experimental data and different theoretical approaches. New and improved experimental data were obtained with the neutron-activation technique. The samples of natural composition of rare earth elements were irradiated with d-t neutrons from the neutron generator NG-300. Gamma-ray spectra of the induced activities of irradiated samples were measured with HPGe spectrometer. The uncertainties of the experimental cross sections were thoroughly estimated. Available experimental results and evaluated nuclear data from the EXFOR, TENDL, ENDF data libraries were compared with different systematics and calculations with the EMPIRE 3.0 and TALYS 1.2 codes. Contribution of pre-equilibrium decay was analyzed. Different systematics for estimations of the investigated cross-sections have been tested

ACRT technique for the single crystal growth of the heavy fermion compound YbRh{sub 2}Si{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Witt, Sebastian; Kliemt, Kristin; Butzke, Constantin; Krellner, Cornelius [Goethe University Frankfurt, 60438 Frankfurt am Main (Germany)

2016-07-01

In the heavy fermion compound YbRh{sub 2}Si{sub 2} the antiferromagnetic ordering below 70 mK close to a quantum critical point is well-studied. Beneath the magnetic ordering a new phase transition was found recently at 2 mK. It is necessary to prepare large and high-quality single crystals for studying the nature of this new phase transition. Besides the optimization of the single crystal growth it is important to investigate single crystals with different isotopes at this phase transition. Here, we report the crystal growth of YbRh{sub 2}Si{sub 2} with the accelerated crucible rotation technique (ACRT). ACRT shows for other compounds, e.g. YAG (yttrium aluminum garnet, Y{sub 3}Al{sub 5}O{sub 12}), that this technique can reduce flux impurities and enhance the yield of larger crystals. We also report the attempt to receive metallic isotopes of ytterbium with metallothermic reduction. Crystals with different isotopes of silicon and ytterbium can be used for NMR measurements to investigate the underlying phenomena of quantum criticality in more detail.

NMR studies in the half-Heusler type compound YbPtSb

Energy Technology Data Exchange (ETDEWEB)

Koyama, T; Abe, M; Mito, T; Ueda, K; Kohara, T [Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297 (Japan); Suzuki, H S, E-mail: t-koyama@sci.u-hyogo.ac.jp [National Institute for Materials Science, Tsukuba 305-0047 (Japan)

2011-01-01

{sup 121}Sb and {sup 19B}Pt nuclear magnetic resonance (NMR) has been studied in the half-Heusler type compound YbPtSb to obtain information on local magnetic behavior. The characteristics of the localized 4f spins are observed in the Cuire-Weiss type behavior of the Knight shifts K for both {sup 121}Sb and {sup 19B}Pt. From the slope of K-{sub {chi}} plots we estimated hyperfine coupling constants of -3.8 and -4.6 kOe/{mu}{sub B} at Sb and Pt sites, respectively. It was found that the spin-echo decay rate 1/T{sub 2} of {sup 121}Sb shows a clear peaks at 10 K. Similar tendency was also observed in case of {sup 19B}Pt. However, static properties do not show any anomalies near 10 K.

Overview of ultraviolet and infrared spectroscopic properties of Yb3+ doped borate and oxy-borates compounds

International Nuclear Information System (INIS)

Sablayrolles, J.

2006-12-01

The trivalent ytterbium ion can give rise to two emissions with different spectroscopic properties: the first one, with a short lifetime, in the ultraviolet (charge transfer emission) is used in detectors such as scintillators, and the other one, with a long lifetime, in the infrared (4f-4f emission) for laser applications. The strong link between material structure and properties is illustrated through ytterbium luminescence study, in the ultraviolet and infrared, inserted in the borate Li 6 Y(BO 3 ) 3 and two oxy-borates: LiY 6 O 5 (BO 3 ) 3 and Y 17,33 B 8 O 38 . For the first time an ytterbium charge transfer emission in oxy-borates has been observed. The calculation of the single configurational coordinate diagram, as well as the thermal quenching, has been conducted under a fundamental approach on the ytterbium - oxygen bond. The study of the ytterbium infrared spectroscopy in these compounds has been realised and an energy level attribution is proposed in the particular case of the borate Li 6 Y(BO 3 ) 3 : Yb 3+ . An original approach is introduced with the study of the charge transfer states for the three compounds by looking at the infrared emission. The first laser performances in three operating modes (continuous wave, Q-switch and mode locking) of a Li 6 Y(BO 3 ) 3 : Yb 3+ crystal are reported. (author)

Rare earth-based quaternary Heusler compounds MCoVZ (M = Lu, Y; Z = Si, Ge with tunable band characteristics for potential spintronic applications

Directory of Open Access Journals (Sweden)

Xiaotian Wang

2017-11-01

Full Text Available Magnetic Heusler compounds (MHCs have recently attracted great attention since these types of material provide novel functionalities in spintronic and magneto-electronic devices. Among the MHCs, some compounds have been predicted to be spin-filter semiconductors [also called magnetic semiconductors (MSs], spin-gapless semiconductors (SGSs or half-metals (HMs. In this work, by means of first-principles calculations, it is demonstrated that rare earth-based equiatomic quaternary Heusler (EQH compounds with the formula MCoVZ (M = Lu, Y; Z = Si, Ge are new spin-filter semiconductors with total magnetic moments of 3 µB. Furthermore, under uniform strain, there are physical transitions from spin-filter semiconductor (MS → SGS → HM for EQH compounds with the formula LuCoVZ, and from HM → SGS → MS → SGS → HM for EQH compounds with the formula YCoVZ. Remarkably, for YCoVZ EQH compounds there are not only diverse physical transitions, but also different types of spin-gapless feature that can be observed with changing lattice constants. The structural stability of these four EQH compounds is also examined from the points of view of formation energy, cohesive energy and mechanical behaviour. This work is likely to inspire consideration of rare earth-based EQH compounds for application in future spintronic and magneto-electronic devices.

Lifetimes Measurements in 160Yb,162Yb,164Yb,166Yb,168Yb

International Nuclear Information System (INIS)

Araddad, S. Y.; El-barouni, A. M.; Rateb, G. M.; Mosbah, D. S.; Elahrash, M. S.; Sergiwa, S. M.

2004-01-01

From our measurements of the lifetimes of high spin states in 168 Yb along with the published lifetime data for the nearby even even ytterbium isotopes, 160-168 Yb using the Recoil Distance Method (RDM) and the Doppler Shift Attenuation Method (DSAM) present a great opportunity to probe systematically the relationship between the nuclear shape changes and the reduction in collectivity. (authors)

Valence mixing in YbCuAl: a case study

International Nuclear Information System (INIS)

Mattens, W.

1980-01-01

Results are presented of a study of the valence state of Yb in the intermetallic compound YbCuAl. Both macroscopic physical properties (magnetic susceptibility, heat capacity, thermal expansion, electric resistivity) and microscopic physical properties (neutron inelastic scattering, nuclear magnetic resonance) are determined. The results are compared with a local Fermi liquid theory. (G.T.H.)

Anomalies of magnetoresistance of compounds with atomic clusters RB12 (R = Ho, Er, Tm, Lu)

International Nuclear Information System (INIS)

Sluchanko, N. E.; Bogach, A. V.; Glushkov, V. V.; Demishev, S. V.; Samarin, N. A.; Sluchanko, D. N.; Dukhnenko, A. V.; Levchenko, A. V.

2009-01-01

The magnetoresistance and magnetization of single-crystal samples of rare-earth dodecaborides RB 12 (R = Ho, Er, Tm, Lu) have been measured at low temperatures (1.8-35 K) in a magnetic field of up to 70 kOe. The effect of positive magnetoresistance that obeys the Kohler's rule Δρ/ρ = f(ρ(0, 300 K)H/ρ(0, T)) is observed for the nonmagnetic metal LuB 12 . In the magnetic dodecaborides HoB 12 , ErB 12 , and TmB 12 , three characteristic regimes of the magnetoresistance behavior have been revealed: the positive magnetoresistance effect similar to the case of LuB 12 is observed at T > 25 K; in the range T N ≤ T ≤ 15 K, the magnetoresistance becomes negative and depends quadratically on the external magnetic field; and, finally, upon the transition to the antiferromagnetic phase (T N ), the positive magnetoresistance is again observed and its amplitude reaches 150% for HoB 12 . It has been shown that the observed anomalies of negative magnetoresistance in the paramagnetic phase can be explained within the Yosida model of conduction electron scattering by localized magnetic moments. The performed analysis confirms the formation of spin-polaron states in the 5d band in the vicinity of rare-earth ions in paramagnetic and magnetically ordered phases of RB 12 and makes it possible to reveal a number of specific features in the transformation of the magnetic structure of the compounds under investigation

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

Transport, Thermal, and Magnetic Properties of YbNi3X9 (X = Al, Ga): A Newly Synthesized Yb-Based Kondo Lattice System

Science.gov (United States)

Yamashita, Tetsuro; Miyazaki, Ryoichi; Aoki, Yuji; Ohara, Shigeo

2012-03-01

We have succeeded in synthesizing a new Yb-based Kondo lattice system, YbNi3X9 (X = Al, Ga). Our study reveals that YbNi3Al9 shows typical features of a heavy-fermion antiferromagnet with a Néel temperature of TN = 3.4 K. All of the properties reflect a competition between the Kondo effect and the crystalline electric field (CEF) effect. The moderate heavy-fermion state leads to an enhanced Sommerfeld coefficient of 100 mJ/(mol\\cdotK2), even if ordered antiferromagnetically. On the other hand, the isostructural gallide YbNi3Ga9 is an intermediate-valence system with a Kondo temperature of TK = 570 K. A large hybridization scale can overcome the CEF splitting energy, and a moderately heavy Fermi-liquid ground state with high local moment degeneracy should form at low temperatures. Note that the quality of single-crystalline YbNi3X9 is extremely high compared with those of other Yb-based Kondo lattice compounds. We conclude that YbNi3X9 is a suitable system for investigating the electronic structure of Yb-based Kondo lattice systems from a heavy-fermion system with an antiferromagnetically ordered ground state to an intermediate-valence system.

Structural, Electronic and Elastic Properties of Heavy Fermion YbTM2 (TM= Ir and Pt) Laves Phase Compounds

Science.gov (United States)

Pawar, H.; Shugani, M.; Aynyas, M.; Sanyal, S. P.

2018-02-01

The structural, electronic and elastic properties of YbTM2 (TM = Ir and Pt) Laves phase intermetallic compounds which crystallize in cubic (MgCu2-type) structure, have been investigated using ab-initio full potential linearized augmented plane wave (FP-LAPW) method with LDA and LDA+U approximation. The calculated ground state properties such as lattice parameter (a0), bulk modulus (B) and its pressure derivative (B‧) are in good agreement with available experimental and theoretical data. The electronic properties are analyzed from band structures and density of states. Elastic constants are predicted first time for these compounds which obey the stability criteria for cubic system.

Affinity of 169Yb, 67Ga and 111In for malignant tumor, (1)

International Nuclear Information System (INIS)

Ando, Itsuko

1975-01-01

The tumor affinity of 169 Yb-citrate, 67 Ga-citrate and 111 In-citrate was examined by using Yoshida sarcoma-bearing rats, and the affinity of these compounds for inflammation was also tested using rats with inflammation induced by croton oil injection. In this investigation there was no great difference in uptake by the tumor tissue of these compounds, but a great difference was observed in the retention value of the blood and uptake rate in the bone. 169 Yb-citrate was cleared rapidly from the blood and was taken mostly into the bone. So the retention values in the soft tissues became very small. On the other hand, 111 In-citrate was slowly and only slightly taken into the bone from the blood, so the retention values in the soft tissue remained relatively high. 67 Ga-citrate showed the intermediate value between the bone uptake rate of 169 Yb-citrate and that of 111 In-citrate. In the following experiments, 169 Yb-citrate and 67 Ga-citrate were compared in four strains: Yoshida sarcoma, Walker carcinosarcoma 256, Sarcoma 180, and Ehrlich tumor. The uptake rate of 169 Yb in tumor tissue was much larger than that of 67 Ga in Ehrlich tumor-bearing mice, but the value of 169 Yb was slightly smaller than those of 67 Ga in Yoshida sarcoma-bearing rats, Walker carcinosarcoma 256-bearing rats and Sarcoma 180-bearing mice. Tumor to organ ratios of 169 Yb, which were most important for tumor scanning, were much larger than those of 67 Ga in all four strains except tumor to bone ratios of 169 Yb. From the above-described facts, it was shown that 169 Yb-citrate had a stronger tumor affinity than 67 Ga-citrate and that the tumor affinity of 169 Yb-citrate was similar in these four strains of tumor bearing animals. These three compounds had a relatively strong affinity with the inflammatory tissue. (auth.)

Evaluation of the 175Lu(n,2n)174Lu, 175Lu(n,2n/sup 174m/Lu, and 175Lu(n,3n)173Lu cross sections from threshold to 20 MeV

International Nuclear Information System (INIS)

Philis, C.; Young, P.G.; Arthur, E.D.

1978-04-01

An evaluation of the 175 Lu(n,2n) 174 Lu, 175 Lu(n,2n)/sup 174m/Lu, and 175 Lu(n,3n) 173 Lu reactions from threshold to 20 MeV is presented. Available experimental data were renormalized to a consistent set of standards and were used along with results from statistical-preequilibrium model calculations to produce recommended curves for each of these reactions

Synthesis, Tunable Multicolor Output, and High Pure Red Upconversion Emission of Lanthanide-Doped Lu2O3 Nanosheets

Directory of Open Access Journals (Sweden)

Lingzhen Yin

2013-01-01

Full Text Available Yb3+ and Ln3+ (Ln = Er, Ho codoped Lu2O3 square nanocubic sheets were successfully synthesized via a facile hydrothermal method followed by a subsequent dehydration process. The crystal phase, morphology, and composition of hydroxide precursors and target oxides were characterized by X-ray diffraction (XRD, field emission scanning electron microscope (FE-SEM, and energy-dispersive X-ray spectroscope (EDS. Results present the as-prepared Lu2O3 crystallized in cubic phase, and the monodispersed square nanosheets were maintained both in hydroxide and oxides. Moreover, under 980 nm laser diode (LD excitation, multicolor output from red to yellow was realized by codoped different lanthanide ions in Lu2O3. It is noteworthy that high pure strong red upconversion emission with red to green ratio of 443.3 of Er-containing nanocrystals was obtained, which is beneficial for in vivo optical bioimaging.

IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd–Lu)

Energy Technology Data Exchange (ETDEWEB)

Mioduski, Tomasz [Institute of Nuclear Chemistry and Technology, 03195 Warszawa (Poland); Gumiński, Cezary, E-mail: cegie@chem.uw.edu.pl [Department of Chemistry, University of Warsaw, 02093 Warszawa (Poland); Zeng, Dewen, E-mail: dewen-zeng@hotmail.com [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

2015-06-15

This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF{sub 4} and YbF{sub 2} (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

Preparation of 177Lu-DOTA/DTPA-Bz-Cys-RGD dimer and biodistribution evaluation in normal mice

International Nuclear Information System (INIS)

Sheng Feng; Jia Bing; Wang Fan; He Weiwei; Liu Zhaofei; Zhao Huiyun

2008-01-01

177 Lu-DOTA-Bz-Cys-RGD dimer and 177 Lu-DTPA-Bz-Cys-RGD dimer were prepared, and the in vitro and in vivo properties were compared. TLC and HPLC show that the labeling yields of two radiolabeled compounds are more than 95% under optimal conditions (pH=5.0, reacting at 100 degree C for 15-20 min), and the two radiolabeled compounds show pretty good in vitro stability. HPLC analyses and lg P values reveal that lipophilicity of 177 Lu-DOTA-Bz-Cys- RGD dimer is higher than 177 Lu-DTPA-Bz-Cys-RGD dimer. The uptake of 177 Lu-DTPA-Bz-Cys- RGD dimer in other tissues is significantly higher than that of 177 Lu-DOTA-Bz-Cys-RGD dimer at 4 h postinjection, except for blood and spleen. The in vivo stability of 177 Lu-DOTA-Bz-Cys-RGD dimer is much better than 177 Lu-DTPA-Bz-Cys-RGD dimer. Bz-DOTA is an ideal bifunctional chelator for 177 Lu labeling of RGD dimer. (authors)

Phase relations in the pseudobinary systems RAO3-R2Ti2O7 (R: rare earth element and Y, A: Fe, Ga, Al, Cr and Mn) and syntheses of new compounds R(A1-xTix)O3+x/2 (2/3≤x≤3/4) at elevated temperatures in air

Science.gov (United States)

Brown, Francisco; Jacobo-Herrera, Ivan; Alvarez-Montaño, Victor; Kimizuka, Noboru; Kurashina, Keiji; Michiue, Yuichi; Matsuo, Yoji; Mori, Shigeo; Ikeda, Naoshi; Medrano, Felipe

2017-07-01

Phase relations in the pseudo-binary systems RFeO3-R2Ti2O7 (R: Lu, Ho and Dy), RGaO3-R2Ti2O7 (R: Lu and Er), LuAlO3-Lu2Ti2O7 and RAO3-R2Ti2O7 (R: Lu and Yb. A: Cr and Mn) at elevated temperatures in air were determined by means of a classic quenching method. There exist Lu(Fe1-xTix)O3+x/2, R(Ga1-xTix)O3+x/2 (R: Lu and Er) and Lu(Al1-xTix)O3+x/2 (2/3≤ x≤3/4) having the Yb(Fe1-xTix)O3+x/2-type of crystal structure (x=0.72, space group: R3m, a(Å)=17.9773 and c(Å)=16.978 as a hexagonal setting) in these pseudo binary systems. Eighteen compounds R(A1-xTix)O3+x/2 (R: Lu-Sm and Y, A: Fe, Ga and Al) were newly synthesized and their lattice constants as a hexagonal setting were measured by means of the X-ray powder diffraction method. The R occupies the octahedral site and both A and Ti does the trigonalbipyramidal one in these compounds. Relation between lattice constants for the rhombic R(A1-xTix)O3+x/2 and the monoclinic In(A1-xTix)O3+x/2 are as follows, ah≈5 x bm, ch≈3 x cm x sin β and am=31/2 x bm, where ah and ch are the lattice constants as a hexagonal setting for R(A1-xTix)O3+x/2 and am, bm, cm and β are those of the monoclinic In(A1-xTix)O3+x/2. Crystal structural relationships among α-InGaO3 (hexagonal, high pressure form, space group: P63/mmc), InGaO3 (rhombic, hypothetical), (RAO3)n(BO)m and RAO3(ZnO)m (R: Lu-Ho, Y and In, A: Fe, Ga, and Al, B: divalent cation element, m, n: natural number), the orthorhombic-and monoclinic In(A1-xTix)O3+x/2 (A: Fe, Ga, Al, Cr and Mn) and the hexagonal-and rhombic R(A1-xTix)O3+x/2 (R: Lu-Sm and Y, A: Fe, Ga and Al) are schematically presented. We concluded that the crystal structures of both the α-InGaO3 (high pressure form, hexagonal, space group: P63/mmc) and the hypothetical InGaO3 (rhombic) are the key structures for constructing the crystal structures of these compounds having the cations with CN=5.

Crystal structures of orthorhombic, hexagonal, and cubic compounds of the Sm(x)Yb(2−x)TiO5 series

International Nuclear Information System (INIS)

Aughterson, Robert D.; Lumpkin, Gregory R.; Reyes, Massey de los; Sharma, Neeraj; Ling, Christopher D.; Gault, Baptiste; Smith, Katherine L.; Avdeev, Maxim; Cairney, Julie M.

2014-01-01

A series of single phase compounds with nominal stoichiometry Sm (x) Yb (2−x) TiO 5 (x=2, 1.4, 1, 0.6, and 0) have been successfully fabricated to generate a range of crystal structures covering the most common polymorphs previously discovered in the Ln 2 TiO 5 series (Ln=lanthanides and yttrium). Four of the five samples have not been previously fabricated in bulk, single phase form so their crystal structures are refined and detailed using powder synchrotron and single crystal x-ray diffraction, neutron diffraction and transmission electron microscopy. Based on the phase information from diffraction data, there are four crystal structure types in this series; orthorhombic Pnma, hexagonal P6 3 /mmc, cubic (pyrochlore-like) Fd-3m and cubic (fluorite-like) Fm-3m. The cubic materials show modulated structures with variation between long and short range ordering and the variety of diffraction techniques were used to describe these complex crystal structure types. - Graphical abstract: A high resolution image of the compound Sm 0.6 Yb 1.4 TiO 5 showing contrast from lattice fringes and the corresponding fast Fourier transform (FFT) of the HREM image with pyrochlore related diffraction spots marked “P” and fluorite marked “F”. The crystal is oriented down the [1 1 0] zone axis based on the Fd-3m structure. The ideal crystal structure (no vacancies) of the cubic, pyrochlore-like (Sm 0.6 Yb 1.4 TiO 5 ). - Highlights: • First fabrication of bulk single-phase material with stoichiometry Sm 2 TiO 5 . • Systematic study of crystal structure types within Ln 2 TiO 5 series (Ln=lanthanides). • A novel technique using IFFT of HREM images to study cubic structures

K-shell absorption jump factors and jump ratios in elements between Tm ( Z = 69) and Os ( Z = 76) derived from new mass attenuation coefficient measurements

Science.gov (United States)

Kaya, Necati; Tıraşoğlu, Engin; Apaydın, Gökhan; Aylıkcı, Volkan; Cengiz, Erhan

2007-08-01

The K-shell absorption jump factors and jump ratios were derived from new mass attenuation coefficients measured using an energy dispersive X-ray fluorescence (EDXRF) spectrometer for Tm, Yb elements being Tm 2O 3, Yb 2O 3 compounds and pure Lu, Hf, Ta, W, Re and Os. The measurements, in the region 56-77 keV, were done in a transmission geometry utilizing the K α1 , K α2 , K β1 and K β2 X- rays from different secondary source targets (Yb, Ta, Os, W, Re and Ir, etc.) excited by the 123.6 keV γ-photons from an 57Co annular source and detected by an Ultra-LEGe solid state detector with a resolution of 150 eV at 5.9 keV. Experimental results have been compared with theoretically calculated values. The measured values of Tm, Yb, Lu, Hf, Ta, W, Re and Os are reported here for the first time.

K-shell absorption jump factors and jump ratios in elements between Tm (Z = 69) and Os (Z = 76) derived from new mass attenuation coefficient measurements

International Nuclear Information System (INIS)

Kaya, Necati; Tirasoglu, Engin; Apaydin, Goekhan; Aylikci, Volkan; Cengiz, Erhan

2007-01-01

The K-shell absorption jump factors and jump ratios were derived from new mass attenuation coefficients measured using an energy dispersive X-ray fluorescence (EDXRF) spectrometer for Tm, Yb elements being Tm 2 O 3 , Yb 2 O 3 compounds and pure Lu, Hf, Ta, W, Re and Os. The measurements, in the region 56-77 keV, were done in a transmission geometry utilizing the K α1 , K α2 , K β1 and K β2 X- rays from different secondary source targets (Yb, Ta, Os, W, Re and Ir, etc.) excited by the 123.6 keV γ-photons from an 57 Co annular source and detected by an Ultra-LEGe solid state detector with a resolution of 150 eV at 5.9 keV. Experimental results have been compared with theoretically calculated values. The measured values of Tm, Yb, Lu, Hf, Ta, W, Re and Os are reported here for the first time

Absorption Spectra Of Rbcl:Yb Rbbr:Yb And Rbi:Yb Crystals ...

African Journals Online (AJOL)

Single crystals of rubidium chloride, bromide and iodide were doped with substitutional divalent ytterbium, Yb ions, by heating them in ytterbium atmosphere. The absorption spectra of the Yb doped crystals were measured at room and liquid nitrogen temperatures. The spectra were found to consist of intense broad ...

Thermoelectric transport in rare-earth compounds

International Nuclear Information System (INIS)

Koehler, Ulrike

2007-01-01

This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce 3 Rh 4 Sn 13 are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu 1-x Yb x Rh 2 Si 2 and Ce x La 1-x Ni 2 Ge 2 by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

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.

Estudo de alguns compostos organolantanídeos: [LnCp2Cl.PPh3

Directory of Open Access Journals (Sweden)

Gatti Paula M.

2000-01-01

Full Text Available In this work we present the synthesis and characterization of some organolanthanide compounds [LnCp2Cl.PPh3], Ln = La, Nd, Eu, Yb and Lu. The catalytic activity of these compounds has been verified in cyclohexene hydrogenation. Cyclohexane was identified by¹H NMR analysis in the reaction products.

Yb14MnSb11 as a High-Efficiency Thermoelectric Material

Science.gov (United States)

Snyder, G. Jeffrey; Gascoin, Franck; Brown, Shawna; Kauzlarich, Susan

2009-01-01

Yb14MnSb11 has been found to be wellsuited for use as a p-type thermoelectric material in applications that involve hotside temperatures in the approximate range of 1,200 to 1,300 K. The figure of merit that characterizes the thermal-to-electric power-conversion efficiency is greater for this material than for SiGe, which, until now, has been regarded as the state-of-the art high-temperature ptype thermoelectric material. Moreover, relative to SiGe, Yb14MnSb11 is better suited to incorporation into a segmented thermoelectric leg that includes the moderate-temperature p-type thermoelectric material CeFe4Sb12 and possibly other, lower-temperature p-type thermoelectric materials. Interest in Yb14MnSb11 as a candidate high-temperature thermoelectric material was prompted in part by its unique electronic properties and complex crystalline structure, which place it in a class somewhere between (1) a class of semiconducting valence compounds known in the art as Zintl compounds and (2) the class of intermetallic compounds. From the perspective of chemistry, this classification of Yb14MnSb11 provides a first indication of a potentially rich library of compounds, the thermoelectric properties of which can be easily optimized. The concepts of the thermoelectric figure of merit and the thermoelectric compatibility factor are discussed in Compatibility of Segments of Thermo - electric Generators (NPO-30798), which appears on page 55. The traditional thermoelectric figure of merit, Z, is defined by the equation Z = alpha sup 2/rho K, where alpha is the Seebeck coefficient, rho is the electrical resistivity, and k is the thermal conductivity.

Investigation of A = 152 radioactivities with mass-separated sources: Identification of /sup 152/Lu

International Nuclear Information System (INIS)

Toth, K.S.; Sousa, D.C.; Nitschke, J.M.; Wilmarth, P.A.

1987-01-01

Nuclides with A = 152 were produced in /sup 58/Ni bombardments of /sup 96/Ru and their decay properties were investigated following on-line mass separation. The isotope /sup 152/Lu (T/sub 1/2/ = 0.7 +- 0.1 s) was identified by γ rays in its β-decay daughter, /sup 152/Yb. Based on its decay characteristics, the parent state has a probable spin and parity assignment of (4,5,6 - ). Several new transitions were observed to follow the β decays of /sup 152/Yb and the /sup 152/Tm low-spin isomer; they established previously unknown levels in both /sup 152/Tm and /sup 152/Er. The additional γ rays in /sup 152/Yb decay reduce from 100% to 88% the direct feeding to the one excited state in /sup 152/Tm that had been known earlier. Nevertheless, the corresponding logft value is calculated to be 3.5, indicating that this is an allowed β transition which connects the 0 + parent with a 1 + excited state in /sup 152/Tm. By comparing the β-decay rates of /sup 148/Dy and /sup 152/Ho, and the α- and β-decay rates of /sup 152/Er, an α branch of 90 +- 4 % was deduced for /sup 152/Er

Growth of Yb3+-doped Y2O3 single crystal rods by the micro-pulling-down method

International Nuclear Information System (INIS)

Mun, J.H.; Novoselov, A.; Yoshikawa, A.; Boulon, G.; Fukuda, T.

2005-01-01

The rare-earth sesquioxides (RE 2 O 3 , RE = Lu, Y and Sc) are very promising host crystals for advanced laser diode (LD)-pumped Yb 3+ -doped solid-state lasers due to unusual combination, almost unique of favourable structural, thermal and spectroscopic properties which are described. In spite of these favourable properties, the bulk single crystal growth technology for the rare-earth sesquioxides has not been established yet. The extremely high melting temperature at around 2400 deg. C has prevented it. However, we shall show that yttrium oxide crystals (Yb x Y 1-x ) 2 O 3 , x = 0.0, 0.005, 0.05, 0.08 and 0.15 of cylindrical shape as laser rods with 4.2 mm in diameter and 15-20 mm in length have been grown from rhenium crucibles by the micro-pulling-down method. The crystal quality characterisation of undoped Y 2 O 3 crystal was determined using X-ray rocking curve (XRC) analysis. Yb were homogeneously distributed in Y 2 O 3 host crystal

Yb valence state in Yb{sub 5}Rh{sub 4}Ge{sub 10}

Energy Technology Data Exchange (ETDEWEB)

Sato, Hitoshi; Arita, Masashi; Shimada, Kenya; Namatame, Hirofumi; Taniguchi, Masaki [Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima (Japan); Utsumi, Yuki [Synchrotron SOLEIL, L' Orme des Merisiers, Gif-sur-Yvette (France); Katoh, Kenichi [Department of Applied Physics, National Defense Academy, Yokosuka (Japan); Mimura, Kojiro [Graduate School of Engineering, Osaka Prefecture University, Sakai (Japan); Ueda, Shigenori [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Hyogo (Japan); Quantum Beam Unit, National Institute for Materials Science, Tsukuba (Japan); Yamaoka, Hitoshi [RIKEN SPring-8 Center, Hyogo (Japan); Rousuli, Awabaikeli [Graduate School of Science, Hiroshima University, Higashi-Hiroshima (Japan); Umeo, Kazunori [NBARD, Hiroshima University, Higashi-Hiroshima (Japan)

2017-06-15

Temperature- and pressure-dependent Yb valence state in Yb{sub 5}Rh{sub 4}Ge{sub 10} has been investigated by means of Yb 3d hard X-ray photoemission spectroscopy (HAXPES) and Yb L{sub 3} absorption spectroscopy (XAS). The mean Yb valence derived from the Yb 3d HAXPES is estimated to be ∝2.78 at 300 K and decreases to ∝2.74 at 20 K. On the other hand, the Yb valence deduced from the Yb L{sub 3} XAS at 300 K is almost constant with ∝2.81 in the pressure range between 9.2 and 34.7 GPa. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Transport and magnetic properties of new heavy-fermion antiferromagnet YbNi{sub 3}Al{sub 9}

Energy Technology Data Exchange (ETDEWEB)

Ohara, S; Yamashita, T; Mori, Y; Sakamoto, I, E-mail: ohara.shigeo@nitech.ac.jp [Department of Engineering Physics, Electronics and Mechanics, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

2011-01-01

We have synthesized a new Yb-based Kondo-lattice compound YbNi{sub 3}Al{sub 9}. This compound crystallizes in a trigonal ErNi{sub 3}Al{sub 9}-type structure (space group R32), in which the Yb-ion is arranged in a two-dimensional honey-comb lattice perpendicular to the c-axis. We report the first measurements of electrical resistivity and magnetization for single-crystalline samples of YbNi{sub 3}Al{sub 9}. The electrical resistivity of YbNi{sub 3}Al{sub 9} is characteristic of the typical properties of heavy-fermion antiferromagnets with a Neel temperature of T{sub N} = 3.4 K. The transport and magnetic properties exhibit large anisotropy in the low-temperature region owing to an interplay among the crystalline-electric-field effect, the Ruderman-Kittel-Kasuya-Yoshida interaction, and the Kondo effect. Below T{sub N}, the metamagnetic transition is observed at a very low magnetic field of around 1 kOe with the field applied along the a-axis. The magnetic structure of YbNi{sub 3}Al{sub 9} is highly sensitive to the applied magnetic field.

Gamma radiation exposure of accompanying persons due to Lu-177 patients

Directory of Open Access Journals (Sweden)

Kovan Bilal

2015-01-01

Full Text Available Neuroendocrine tumours (NET are cancers usually observed and arisen in the stomach, intestine, pancreas and breathing system. Recently, radionuclide therapy applications with Lu-177 peptide compound are rapidly growing; especially effective clinical results are obtained in the treatment of well-differentiated and metastatic NET. In this treatment, Lu-177-DOTA, a beta emitter radioisotope in the radiopharmaceutical form, is given to the patient by intravenous way. Lu-177 has also gamma rays apart from beta rays. Gamma rays have 175 keV average energy and these gamma rays should be under the control in terms of radiation protection. In this study, we measured the exposure dose from the Lu-177 patient.

Thermodynamic and transport properties of YbNi 4Cd

Science.gov (United States)

Lee, J.; Park, H.; Lee-Hone, N. R.; Broun, D. M.; Mun, E.

2018-05-01

The single crystal growth and the physical properties of the intermetallic compounds R Ni4Cd (R =Y and Yb) which crystallize in the face-centered cubic (fcc) MgCu4Sn -type structure (space group F 4 ¯3 m ) are discussed. Thermodynamic and transport properties of YbNi4Cd are studied by measuring the magnetization, electrical resistivity, and specific heat. The magnetic susceptibility measurement shows that the 4 f electrons of Yb3 + ions are well localized. The electrical resistivity and specific heat exhibits an antiferromagnetic ordering below TN=0.97 K. Applying the field along the [111] direction results in the suppression of TN below 0.4 K at the critical field Hc˜4.5 kOe. No non-Fermi liquid behavior has been observed in the vicinity of Hc. Above Hc, the magnetoresistivity shows an unconventional temperature dependence ρ (T ) =ρ0+A Tn with n >2 , suggesting that an additional scattering mechanism in the resistivity needs to be considered. Based on the analysis of experimental results, we conclude that the Yb3 + moments and conduction electrons are weakly coupled. Despite the antiferromagnetic ordering below TN, YbNi4Cd exhibits a large frustration parameter | θp/TN|˜16 , where the magnetic Yb3 + ions occupy the tetrahedra on the fcc lattice.

Study of quantitative analysis of rare earth elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in soil samples by inductively couple plasma mass spectrometry

International Nuclear Information System (INIS)

Truong Duc Toan; Nguyen Giang; Vo Tran Quang Thai; Do Tam Nhan; Nguyen Le Anh; Nguyen Viet Duc; Luong Thi Tham; Truong Thi Phuong Mai

2015-01-01

Method for the determination of 16 rare earth elements (REEs) in soil samples without separating by inductively coupled plasma mass spectrometry (ICP-MS) has been studied at Dalat Nuclear Research Institute. The optimal conditions for ICP-MS NexION 300X with three modes: Standard, Collision (KED), and Reaction (DRC) have been studied on the Montana II soil reference material. The result analysis shows that: DRC mode only gives good analysis result for Sc, Y, La, Ce, Pr, Nd, Tm, Yb, and Lu; Standard mode exhibits good analysis results for all elements with error from 1.2 - 29.0% and KED mode is the best one with error less than 15%. The concentrations of elements in the soil samples of Cau Dat, Bao Loc, and Da Lat were determined, which concentrations of REEs in soil samples of Cau Dat are higher than that of the other areas in Lam Dong Province. (author)

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

Synthesis and up-conversion white light emission of RE{sup 3+}-doped lutetium oxide nanocubes as a single compound

Energy Technology Data Exchange (ETDEWEB)

Hu Shanshan [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yang Jun, E-mail: jyang@swu.edu.cn [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Li Chunxia [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Lin Jun, E-mail: jlin@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2012-04-16

Highlights: Black-Right-Pointing-Pointer Uniform and dispersive cubic precursor can be synthesized by sample hydrothermal process. Black-Right-Pointing-Pointer Hydrothermal precursor could transform to Lu{sub 2}O{sub 3}:RE{sup 3+} with its original cubic morphology. Black-Right-Pointing-Pointer Nearly equal intensities of blue, green, and red emissions under single 980 nm laser. Black-Right-Pointing-Pointer Lu{sub 2}O{sub 3}:RE{sup 3+} show bright white light emission, clearly visible to the naked eyes. Black-Right-Pointing-Pointer Chromaticity coordinate is very close to the standard equal energy white light illuminate. - Abstract: Uniform and dispersive Lu{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+}/Tm{sup 3+} nanocubes have been successfully synthesized by hydrothermal process with subsequent calcination at 900 Degree-Sign C. The as-formed RE{sup 3+}-doped lutetium oxide precursor via the hydrothermal process, as a template, could transform to RE{sup 3+}-doped Lu{sub 2}O{sub 3} with their original cubic morphology and slight shrinkage in the size after post-annealing process. The formation mechanism for the lutetium oxide precursor cubes has been proposed. Under single wavelength diode laser excitation of 980 nm, the as-obtained Lu{sub 2}O{sub 3}:3%Yb{sup 3+}/0.5%Er{sup 3+}/0.3%Tm{sup 3+} nanocubes show nearly equal intensities of blue (Tm{sup 3+}: {sup 1}G{sub 4} {yields} {sup 3}H{sub 6}), green (Er{sup 3+}: ({sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}) {yields} {sup 4}I{sub 15/2}), and red (Er{sup 3+}: {sup 4}F{sub 9/2} {yields} {sup 4}I{sub 15/2}) emissions, which produces bright white light emission, clearly visible to the naked eyes. The main pathways to populate the upper emitting states come from the energy-transfer processes from Yb{sup 3+} to Tm{sup 3+}/Er{sup 3+}, respectively. The chromaticity coordinate of the Lu{sub 2}O{sub 3}:3%Yb{sup 3+}/0.5%Er{sup 3+}/0.3%Tm{sup 3+} sample is calculated to be about x = 0.3403 and y = 0.3169, which falls exactly within the

Electronic structure and X-ray spectroscopic properties of YbNi_2P_2

International Nuclear Information System (INIS)

Shcherba, I.D.; Bekenov, L.V.; Antonov, V.N.; Noga, H.; Uskokovic, D.; Zhak, O.; Kovalska, M.V.

2016-01-01

Highlights: • We present new experimental and theoretical data for YbNi_2P_2. • The presence of divalent and trivalent Yb ion found in YbNi_2P_2. • The calculation show good agreement with the experimental measurements. - Abstract: X-ray absorption spectrum at the Yb L_3 edge and X-ray emission spectra of Ni and P at the K and L_2_,_3 edges have been studied experimentally and theoretically in the mixed valent compound YbNi_2P_2 with ThCr_2Si_2 type crystal structure. The electronic structure of YbNi_2P_2 is investigated using the fully relativistic Dirac linear muffin-tin orbital (LMTO) band-structure method. The effect of the spin–orbit (SO) interaction and Coulomb repulsion U on the electronic structure of YbNi_2P_2 is examined in the frame of the LSDA + SO + U method. The core-hole effect in the final states as well as the effect of the electric quadrupole E_2 transitions have been investigated. A good agreement between the theory and the experiment was found. Both the trivalent and the divalent Yb ions in YbNi_2P_2 are reflected in the experimentally measured Yb L_3 X-ray absorption spectrum simultaneously. We found that the best agreement between the experimental spectrum and sum of the theoretically calculated Yb"2"+ and Yb"3"+ spectra is achieved with 73% ytterbium ions in 2+ state and 27% ions in 3+ state.

Progress in the development of LuAlO$_{3}$ based scintillators

CERN Document Server

Belsky, A; Lecoq, P; Dujardin, C; Garnier, N; Canibano, H; Pédrini, C; Petrosian, A

2000-01-01

LuAlO/sub 3/:Ce/sup 3+/ (LuAP) and Lu/sub x/Y/sub 1/-xAlO/sub 3/:Ce /sup 3+/ (LuYAP) crystals are used as scintillation materials for positron emission tomography. The actual study of these scintillators develops in three directions: (i) growth of large size LuAP crystals with stable properties, (ii) the relationship between the composition of LuYAP crystals and scintillation properties, and (iii) scintillation mechanisms in lutetium compounds. After improving of growth conditions a large size samples (length >40 mm) have been prepared. Crystals show a good correlation between growth parameters, light yield and transmission spectra. We studied a series of samples with calibrated size (2*2*10 mm3) and compare the light yield with standard BGO and LSO samples. Mixed crystals with composition of 0.6

Preparation and spectroscopic properties of Yb-doped and Yb-Al-codoped high silica glasses

International Nuclear Information System (INIS)

Qiao Yanbo; Wen Lei; Wu Botao; Ren Jinjun; Chen Danping; Qiu Jianrong

2008-01-01

Yb-doped and Yb-Al-codoped high silica glasses have been prepared by sintering nanoporous glasses. The absorption, fluorescent spectra and fluorescent lifetimes have been measured and the emission cross-section and minimum pump intensities were calculated. Codoping aluminum ions enhanced the fluorescence intensity of Yb-doped high silica glass obviously. The emission cross-sections of Yb-doped and Yb-Al-codoped high silica glasses were 0.65 and 0.82 pm 2 , respectively. The results show that Yb-Al-codoped high silica glass has better spectroscopic properties for a laser material. The study of high silica glass doped with ytterbium is helpful for its application in Yb laser systems, especially for high-power and high-repetition lasers

Thermoelectric transport in rare-earth compounds

Energy Technology Data Exchange (ETDEWEB)

Koehler, Ulrike

2007-07-01

This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce{sub 3}Rh{sub 4}Sn{sub 13} are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu{sub 1-x}Yb{sub x}Rh{sub 2}Si{sub 2} and Ce{sub x}La{sub 1-x}Ni{sub 2}Ge{sub 2} by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

Effect of Pressure on Valence and Structural Properties of YbFe₂Ge₂ Heavy Fermion Compound A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

Energy Technology Data Exchange (ETDEWEB)

Kumar, Ravhi S.; Svane, Axel; Vaitheeswaran; #8741; , Ganapathy; Kanchana, Venkatakrishnan; Antonio, Daniel; Cornelius, Andrew L.; Bauer, Eric D.; Xiao, Yuming; Chow, Paul (Aarhus); (CIW); (Hyderabad - India); (IIT-India); (LANL); (UNLV)

2016-06-03

The crystal structure and the Yb valence of the YbFe₂Ge₂ heavy fermion compound was measured at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. Furthermore, the measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. While the ThCr₂Si₂-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence from v = 2.72(2) at ambient pressure to v = 2.93(3) at ~9 GPa, where at low temperature a pressure-induced quantum critical state was reported.

Properties of the divalent-Yb compound YbAu.sub.2./sub.Si.sub.2./sub. under extreme conditions

Czech Academy of Sciences Publication Activity Database

Kaštil, Jiří; Míšek, Martin; Kamarád, Jiří; Arnold, Zdeněk; Vlášková, K.; Prchal, J.; Diviš, M.; Doležal, P.; Prokleška, J.; Valenta, J.; Fikáček, J.; Rudajevová, A.; Kriegner, D.

2017-01-01

Roč. 505, Jan (2017), s. 41-44 ISSN 0921-4526 R&D Projects: GA ČR GA15-03777S Institutional support: RVO:68378271 Keywords : YbAu 2 Si 2 * valence state * high pressure * GGA method Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.386, year: 2016

Unusual antiferromagnetic structure of YbCo{sub 2}Si{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Mufti, N. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Department of Physics, State University of Malang, Malang (Indonesia); Kaneko, K. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai (Japan); Hoser, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Gutmann, M. [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot (United Kingdom); Geibel, C.; Stockert, O. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Krellner, C. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Physikalisches Institut, Goethe-Universitaet Frankfurt, Frankfurt (Germany)

2016-07-01

We report on extensive powder and single crystal neutron diffraction experiments to study the magnetic structure in YbCo{sub 2}Si{sub 2} below the Neel temperature T{sub N} = 1.7 K in detail. Representation analysis has been used to find the possible magnetic structure models compatible with the experiments. Two different magnetically ordered phases can clearly be distinguished. At lowest temperatures a commensurate magnetic structure with a propagation vector k{sub 1} = (0.25 0.25 1) and equal moments or about 1.4 μ{sub B}/Yb is found, while the intermediate phase (T > 0.9 K) is characterized by an incommensurate amplitude-modulated magnetic structure with k{sub 2} = (0.25 0.086 1). The magnetic structure in YbCo{sub 2}Si{sub 2} is in stark contrast to all other compounds of the RCo{sub 2}Si{sub 2} family (R = rare earth element) likely due to some itineracy of the Yb 4f states being responsible for the magnetism.

First principle studies of electronic and magnetic properties of Lanthanide-Gold (RAu) binary intermetallics

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Sardar [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Chemistry, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Ahmad, Rashid, E-mail: rashmad@gmail.com [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Chemistry, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Jalali-Asadabadi, S. [Department of Physics, Faculty of Sciences, University of Isfahan (UI), Hezar Gerib Avenue, Isfahan 81746-73441 (Iran, Islamic Republic of); Ali, Zahid [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Physics, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Ahmad, Iftikhar [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Vice Chancellor, Abbott Abad University of Science and Technology, Abbott Abad (Pakistan)

2017-01-15

In this article we explore the electronic and magnetic properties of RAu intermetallics (R=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) for the first time. These properties are calculated by using GGA, GGA+U and hybrid density functional theory (HF) approaches. Our calculations show that HF provides superior results, consistent to the experimentally reported data. The chemical bonding between rare-earth and gold atoms within these compounds are explained on the basis of spin dependent electronic clouds in different planes, which shows predominantly ionic and metallic nature between Au and R atoms. The Cohesive energies of RAu compounds show direct relation with the melting points. Spin-dependent electronic band structure demonstrates that all these compounds are metallic in nature. The magnetic studies show that HoAu and LuAu are stable in non-magnetic structure, PrAu is stable in ferromagnetic phase and CeAu, NdAu, SmAu, GdAu, TbAu, DyAu, ErAu, TmAu, YbAu are anti-ferromagnetic materials.

Design, synthesis and luminescence properties of Ba2 YB2 O6 Cl- and Ba2 YB2 O6 F-based phosphors.

Science.gov (United States)

Chen, Wanping; Yang, Xin; Liu, Yan; Dai, Xiaoyan

2015-05-01

Using a high-temperature solid-state reaction, the chlorine in Ba2 YB2 O6 Cl is gradually replaced by F, and a new compound with the nominal chemical formula Ba2 YB2 O6 F and two phosphors doped with Ce(3+) and Eu(3+) , respectively, are obtained. X-Ray diffraction and photoluminescence spectroscopy are used to characterize the as-synthesized samples. The as-synthesized Ba2 YB2 O6 Cl exhibits bright blue emission in the spectral range ~ 330-410 nm with a maximum around 363 nm under X-ray or UV excitation. Ba2 YB2 O6 F:0.01Ce(3+) exhibits blue emission in the range ~ 340-570 nm with a maximum around 383 nm. Ba2 YB2 O6 F:0.01Eu(3+) exhibits a predominantly (5) D0 -(7)  F2 emission (~610 nm) and the relative intensities of the (5) D0 -(7)  F0,1,2 emissions are tunable under different wavelength UV excitation. The luminescence behaviors of the two phosphors are explained simply in terms of the host composition and site occupancy probability of Ce(3+) and Eu(3+) , respectively. The results indicate that these phosphors have potential application as a blue phosphor or as a red phosphor. Copyright © 2014 John Wiley & Sons, Ltd.

Neutron inelastic scattering experiments on the mixed-valent compound YbCuAl

International Nuclear Information System (INIS)

Mattens, W.C.M.; de Boer, F.R.; Murani, A.P.; Lander, G.H.

1979-01-01

The dynamical susceptibility of YbCuAl has been established by means of time of flight neutron scattering experiments. Non-Korringa behavior of the quasi-elastic line-width has been found and comparison with NMR data will be given

Synthesis, structure and physical properties of YbNi3Al9.23

International Nuclear Information System (INIS)

Tobash, P H; Ronning, F; Thompson, J D; Scott, B L; Bauer, E D; Jiang, Yu; Booth, C H

2011-01-01

The physical properties of YbNi 3 Al 9.23(1) , including the crystal structure, magnetization, specific heat, valence, and electrical resistivity, are reported. Single crystal x-ray diffraction reveals that the compound crystallizes with the rhombohedral space group R32 and has unit cell parameters a = 7.2443(3) A and c = 27.251(3) A with some crystallographic disorder at Al sites. The compound orders antiferromagnetically at T N = 3 K despite the presence of strong ferromagnetic correlations, accompanied by a spin-flop-like transition to a moment-aligned state above 0.1 T. X-ray absorption spectroscopy and magnetic susceptibility measurements indicate a localized Yb 3+ electronic configuration, while the Sommerfeld coefficient for the magnetically ordered state was determined as approximately 135 mJ mol -1 K -2 , suggesting moderately heavy fermion behavior. Therefore, these data indicate a balance between competing Ruderman-Kittel-Kasuya-Yosida (RKKY) and Kondo interactions in YbNi 3 Al 9.23(1) with a somewhat dominant RKKY interaction that leads to a relatively high ordering temperature.

Four-quasiparticle isomers and K-forbidden transitions in 176Lu

International Nuclear Information System (INIS)

McGoram, T.R.; Dracoulis, G.D.; Kibedi, T.; Mullins, M.; Byrne, A.P.; Baxter, A.M.

2000-01-01

Full text: The odd-odd nucleus 176 Lu has been the subject of extensive experimental and theoretical investigation over the last forty years. Much of this interest has stemmed from the role of 176 Lu in the s-process in nucleosynthesis. From a nuclear structure perspective, 176 Lu resides in a region of the nuclear chart where collective rotation and high-K, multi-quasiparticle states compete to form the yrast line (the locus of state with the lowest energy at a given angular momentum). The electromagnetic decay of intermediate and high-K states is often hindered due to the K-selection rule, while apparent violations of this selection rule have been ascribed to Coriolis mixing, shape changes in the gamma-degree of freedom, and so-called 'statistical' mixing. The relative importance of these mechanisms remains an open question. We present here the results of gamma-ray and conversion-electron spectroscopic measurements, performed at the Heavy Ion Facility at the Australian National University in Canberra, using the reaction 176 Yb( 7 Li, α3n) at a beam energy of 45 MeV. Two new four-quasiparticle isomers have been established, with mean lives of 400(100)ns and 58(5)μs, and spin projections and parities of 12 + and (14 + ) respectively. The shorter--lived isomer displays both normal and anomalous K-forbidden decays, which we show is the result of two-state mixing between the isomeric state and a member of a two-quasiparticle rotational band. The implied mixing matrix element of only 5 eV shows explicitly that very small mixing matrix elements may be responsible for anomalous K-hindered decays

Progress in the development of LuAlO3 based scintillators

CERN Document Server

Belsky, A; Lecoq, P; Dujardin, C; Garnier, N; Canibano, H; Pédrini, C; Petrosian, A

2000-01-01

LuAlO3:Ce3+ (LuAP) and LuxY1-xAlO3:Ce3+ (LuYAP) crystals are the promote scintillation materials for Positron Emission Tomography. Actual study of these scintillators develops in the tree directions: (i) growth of large size LuAP crystals with stable properties, (ii) relationship between composition of LuYAP crystals and scintillation properties, and (iii) scintillation mechanisms in lutetium compounds. After improving of growth conditions a large size samples (length greater than 40 mm) have been prepared. Crystals show a good correlation between growth parameters, light yield and transmission spectra. We performed a series of samples with calibrated size (2x2x10 mm3) and compare the light yield with a standard BGO and LSO samples. Mixed crystals with composition of 0.6 less than x less than 0.8 show a significant increase of light yield. We suggest that the short order clusterisation in mixed crystals may by playing an important role in governing the scintillation efficiency. In order to clarify the scintil...

First-principles study of electronic and elastic properties of LuAl{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Shukla, Pushplata, E-mail: pujashukla50@gmail.com; Shrivastava, Deepika; Sanyal, Sankar P. [Department of Physics, Barkatullah university, Bhopal 462026 (India)

2016-05-06

A systematic theoretical study of electronic structure of rare earth intermetallic LuAl{sub 3} has been carried out using full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) within the generalized gradient approximation(GGA) for exchange and correlation potential. The ground state properties such as lattice constant (a{sub o}), bulk modulus (B) and pressure derivative of bulk modulus (B′) were evaluated. LuAl{sub 3} has the cubic AuCu{sub 3} type crystal structure. The electronic properties of this compound have been analyzed quantatively from band structure and DOS. It is clear from band structure that this compound is metallic in nature. The calculated elastic constants infer that this compound is mechanically stable.

Low-temperature phase diagram of YbBiPt

International Nuclear Information System (INIS)

Movshovich, R.; Lacerda, A.; Canfield, P.C.; Thompson, J.D.; Fisk, Z.

1994-01-01

Resistivity measurements are reported on the cubic heavy-fermion compound YbBiPt at ambient and hydrostatic pressures to ∼19 kbar and in magnetic fields to 1 T. The phase transition at T c =0.4 K is identified by a sharp rise in resistivity. That feature is used to build low-temperature H-T and P-T phase diagrams. The phase boundary in the H-T plane follows the weak-coupling BCS expression remarkably well from T c to T c /4, while small hydrostatic pressure of ∼1 kbar suppresses the low-temperature phase entirely. These effects of hydrostatic pressure and magnetic field on the phase transition are consistent with an spin-density-wave (SDW) formation in a very heavy electron band at T=0.4 K. Outside of the SDW phase at low temperature, hydrostatic pressure increases the T 2 coefficient of resistivity, signaling an increase in heavy-fermion correlations with hydrostatic pressure. The residual resistivity decreases with pressure, contrary to trends in other Yb heavy-fermion compounds

New ternary superconductors of the YPd2Sn-type

International Nuclear Information System (INIS)

Ishikawa, M.; Jorda, J.L.; Junod, A.

1982-01-01

From the specific heat and electrical resistivity experiments on several new superconducting Heusler compounds of the YPd 2 Sn-type, it is concluded that these compounds are strong-coupling superconductors with d-character. Most of the compounds with the heavy rare earths substituted for Y order magnetically at a relatively low temperature (< or approx. 5 K) and the compounds of Tm, Yb and Lu exhibit superconductivity below about 3 K. A possible coexistence of superconductivity and magnetism in these compounds is discussed. (orig.)

Photoemission and the electronic properties of heavy fermions -- limitations of the Kondo model

International Nuclear Information System (INIS)

Joyce, J.J.; Arko, A.J.; Andrews, A.B.

1993-01-01

The electronic properties of Yb-based heavy fermions have been investigated by means of high resolution synchrotron radiation photoemission and compared with predictions of the Kondo model. The Yb heavy fermion photoemission spectra show massive disagreement with the Kondo model predictions (as calculated within the Gunnarsson-Schonhammer computational method). Moreover, the Yb heavy fermion photoemission spectra give very strong indications of core-like characteristics and compare favorable to purely divalent Yb metal and core-like Lu 4f levels. The heavy fermions YbCu 2 Si 2 , YbAgCu 4 and YbAl 3 were measured and shown to have lineshapes much broader and deeper in binding energy than predicted by the Kondo model. The lineshape of the bulk component of the 4f emission for these three heavy fermion materials was compared with that from Yb metal and the Lu 4f levels in LuAl 3 , the heavy fermion materials show no substantive spectroscopic differences from simple 4f levels observed in Yb metal and LuAl 3 . Also, the variation with temperature of the 4f fineshape was measured for Yb metal and clearly demonstrates that phonon broadening plays a major role in 4f level lineshape analysis and must be accounted for before considerations of correlated electron resonance effects are presumed to be at work

Spectroscopic studies of lutetium pyro-silicates Lu2Si2O7 doped with bismuth and europium

International Nuclear Information System (INIS)

Bretheau-Raynal, Francoise

1981-01-01

Single crystals of thortveitite structure pyro-silicates were grown by a floating zone technique associated with an arc image furnace. The samples were systematically characterized by X-Ray diffraction and microprobe analysis. Thanks to oriented single crystals of Lu 2 Si 2 O 7 , Yb 2 Si 2 O 7 and Sc 2 Si 2 O 7 , the recorded infrared and Raman spectra allow complete attribution of internal and external vibration modes, in good agreement with group theory predictions for C 2h factor group. Spectroscopic studies of Eu 3+ doping ion in Lu 2 Si 2 O 7 confirm C 2 point symmetry for the cationic site. Oscillator strengths and Judd-Ofelt parameters for Eu 3+ were calculated. A three level scheme ( 1 S 0 , 3 P 0 , 3 P 1 ) of Bi 3+ ion is used to explain radiative and non radiative mechanisms in Lu 2 Si 2 O 7 doped with bismuth. Finally, the mechanisms of low temperature (T =9 K) energy transfer between Bi 3+ and Eu 3+ in lutetium pyro-silicate was studied. The transfer occurs by non radiative process, without any diffusion of the excitation energy within the donor system and is due to dipole-dipole interactions between Bi 3+ and Eu 3+ ions. (author) [fr

Characterization of the electronic properties of YB{sub 4} and YB{sub 6} using {sup 11}B NMR and first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Jaeger, B.; Paluch, S.; Wolf, W.; Herzig, P.; Zogal, O.J.; Shitsevalova, N.; Paderno, Y

2004-11-30

Two compounds, tetragonal YB{sub 4} and cubic YB{sub 6}, have been investigated by electric-field gradient (EFG) and Knight shift measurements at the boron sites using the {sup 11}B nuclear magnetic resonance (NMR) technique and by performing first-principles calculations. In YB{sub 6} {sup 11}B (I=3/2) NMR spectra reveal patterns typical for an axially symmetric field gradient with a quadrupole coupling frequency of {nu}{sub Q}=600{+-}15 kHz. In the second boride (YB{sub 4}) three different EFGs were observed corresponding to the three inequivalent crystallographic sites for the boron atoms (4h, 4e, and 8j). They correspond to: {nu}{sub Q}(4h)=700{+-}30 kHz with an asymmetry parameter {eta}=0.02{+-}0.02, {nu}{sub Q}(4e)=515{+-}30 kHz, {eta}=0.00+0.02/-0.00, and {nu}{sub Q}(8j)=515{+-}40 kHz, {eta}=0.46{+-}0.08. The Knight shifts measured by magic-angle spinning (MAS) NMR at room temperature are very small being 0.6{+-}8 and -1{+-}8 ppm for YB{sub 4} and YB{sub 6}, respectively. For the theoretical calculations structure optimizations were performed as a first step. For the obtained structural parameters the EFGs were computed within the local-density approximation. Very satisfactory agreement between experimental and theoretical results is obtained both for the structural parameters and the B EFGs, thus confirming the underlying structural models. In addition to the EFGs, band structures, densities of states, and valence-electron densities are presented and the bonding situation in the two yttrium borides is discussed. The band-structure results are compatible with the very low values for the Knight shifts mentioned above.

Electronic structure and X-ray spectroscopic properties of YbNi{sub 2}P{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Shcherba, I.D., E-mail: ishcherba@gmail.com [Institute of Technology, University of Pedagogy, Podchorazych 2, 30-084 Krakow (Poland); Lviv National University by Ivan Franko, Lviv (Ukraine); Bekenov, L.V.; Antonov, V.N. [Institute for Metal Physics, 36 Vernadsky Street, 03142 Kiev (Ukraine); Noga, H. [Institute of Technology, University of Pedagogy, Podchorazych 2, 30-084 Krakow (Poland); Uskokovic, D. [Institute of Technical Sciences, SASA, Belgrade (Serbia); Zhak, O.; Kovalska, M.V. [Lviv National University by Ivan Franko, Lviv (Ukraine)

2016-10-15

Highlights: • We present new experimental and theoretical data for YbNi{sub 2}P{sub 2}. • The presence of divalent and trivalent Yb ion found in YbNi{sub 2}P{sub 2}. • The calculation show good agreement with the experimental measurements. - Abstract: X-ray absorption spectrum at the Yb L{sub 3} edge and X-ray emission spectra of Ni and P at the K and L{sub 2,3} edges have been studied experimentally and theoretically in the mixed valent compound YbNi{sub 2}P{sub 2} with ThCr{sub 2}Si{sub 2} type crystal structure. The electronic structure of YbNi{sub 2}P{sub 2} is investigated using the fully relativistic Dirac linear muffin-tin orbital (LMTO) band-structure method. The effect of the spin–orbit (SO) interaction and Coulomb repulsion U on the electronic structure of YbNi{sub 2}P{sub 2} is examined in the frame of the LSDA + SO + U method. The core-hole effect in the final states as well as the effect of the electric quadrupole E{sub 2} transitions have been investigated. A good agreement between the theory and the experiment was found. Both the trivalent and the divalent Yb ions in YbNi{sub 2}P{sub 2} are reflected in the experimentally measured Yb L{sub 3} X-ray absorption spectrum simultaneously. We found that the best agreement between the experimental spectrum and sum of the theoretically calculated Yb{sup 2+} and Yb{sup 3+} spectra is achieved with 73% ytterbium ions in 2+ state and 27% ions in 3+ state.

Microstructural and electrical characteristics of rare earth oxides doped ZnO varistor films

Science.gov (United States)

Jiao, Lei; Mei, Yunzhu; Xu, Dong; Zhong, Sujuan; Ma, Jia; Zhang, Lei; Bao, Li

2018-02-01

ZnO-Bi2O3 varistor films doped with two kinds of rare earth element oxides (Lu2O3 and Yb2O3) were prepared by the sol-gel method. The effects of Lu2O3/Yb2O3 doping on the microstructure and electrical characteristics of ZnO-Bi2O3 varistor films were investigated. All samples show a homogenized morphology and an improved nonlinear relationship between the electric field (E) and current density (I). Both Yb2O3 and Lu2O3 doping can decrease the grain size of ZnO-Bi2O3 varistor films and improve the electrical properties, which have a positive effect on the development of ZnO varistor ceramics. Yb2O3 doping significantly increases the dielectric constant at low frequency. 0.2 mol. % Yb2O3 doped ZnO-Bi2O3 varistor films exhibit the highest nonlinear coefficient (2.5) and the lowest leakage current (328 μA) among Lu2O3/Yb2O3 doped ZnO-Bi2O3 varistor films. Similarly, 0.1 mol. % Lu2O3 doping increases the nonlinear coefficient to 1.9 and decrease the leakage current to 462 μA.

Systematic analysis of hot Yb{sup *} isotopes using the energy density formalism

Energy Technology Data Exchange (ETDEWEB)

Jain, Deepika; Sharma, Manoj K.; Rajni [Thapar University, School of Physics and Materials Science, Patiala (India); Kumar, Raj [University of Padova, Department of Physics and Astronomy, Padova (Italy); Gupta, Raj K. [Panjab University, Department of Physics, Chandigarh (India)

2014-10-15

A systematic study of the spin-orbit density interaction potential is carried out, with spherical as well as deformed choices of nuclei, for a variety of near-symmetric and asymmetric colliding nuclei leading to various isotopes of the compound nucleus Yb{sup *}, using the semiclassical extended Thomas-Fermi formulation (ETF) of the Skyrme energy density formalism (SEDF). We observe that the spin-orbit density interaction barrier height (V{sub JB}) and barrier position (R{sub JB}) increase systematically with the increase in number of neutrons in both the projectile and target, for spherical systems. On allowing deformation effects with optimum orientations, the barrier-height increases by a large order of magnitude, as compared to the spherical case, in going from {sup 156}Yb{sup *} to {sup 172}Yb{sup *} nuclear systems formed via near-symmetric Ni+Mo or asymmetric O+Sm colliding nuclei, except that for the oblate-shaped nuclei, the V{sub JB} is the highest and R{sub JB} shifts towards a smaller (compact) interaction radius. The temperature does not change the behavior of spin-orbit density dependent (V{sub J}) and independent (V{sub P}) interaction potentials, except for some minor changes in the magnitude. The orientation degree of freedom also plays an important role in modifying the barrier characteristics and hence produces a large effect on the fusion cross section. The fusion excitation function of the compound nuclei {sup 160,} {sup 164}Yb{sup *} formed in different incoming channels, show clearly that the new forces GSkI and KDE0v1 respond better than the old SIII force. Among the first two, KDE0v1 seems to perform better. The fusion cross-sections are also predicted for a few other isotopes of Yb{sup *}. (orig.)

Sequential growth of sandwiched NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell–shell nanoparticles for photodynamic therapy

Energy Technology Data Exchange (ETDEWEB)

Peng, Huang-Yong; Ding, Bin-Bin; Ma, Yin-Chu [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Sun, Shi-Qi [State Key Laboratory of Veterinary Etiological Biology and Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, Gansu 730046 (China); Tao, Wei [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Guo, Yan-Chuan [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Guo, Hui-Chen, E-mail: ghch-2004@hotmail.com [State Key Laboratory of Veterinary Etiological Biology and Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, Gansu 730046 (China); Yang, Xian-Zhu, E-mail: yangxz@hftu.edu.cn [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Qian, Hai-Sheng, E-mail: shqian@hfut.edu.cn [Department of Medical Materials and Rehabilitation Engineering, School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China)

2015-12-01

Graphical abstract: The monodisperse elliptical NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell–shell nanoparticles have been synthesized successfully by a facile sequential growth process, which can be used as transducer for photodynamic therapy of cancer cells. - Highlights: • The NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb nanoparticles have been fabricated successfully. • The as-prepared nanoparticles show strong fluorescence excited at 980 or 808 nm. • The nanoparticles were transferred into the aqueous phase via a facile process. • Photosensitizers were loaded into the composites for photodynamic therapy. - Abstract: Upconversion (UC) nanostructures have attracted much interest for their extensive biological applications. In this work, we describe a sequential synthetic route to prepare sandwiched NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell upconversion nanoparticles. The as-prepared products were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM, JEM 2100F), respectively. The as-prepared core–shell nanoparticles of NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb are composed of elliptical nanoparticles with a length of 80 nm and width of 42 nm, which show efficient upconversion fluorescence excited at 808 nm indicating the formation of core–shell–shell sandwiched nanostructures. In addition, the as-prepared sandwiched NaYF{sub 4}:Yb/Er@NaYF{sub 4}:Yb@NaNdF{sub 4}:Yb core–shell upconversion nanoparticles also show strong upconversion fluorescence excited at 980 nm. Amphiphilic mPEG{sub 2k}-b-PEBEP{sub 6K} copolymers (denoted as PPE) were chosen to transfer these hydrophobic UCNPs into the aqueous phase for biological application. In vitro photodynamic therapy of cancer cells show that the viability of cells incubated with the nanoparticles loaded with MC 540 was significantly lower as compared to the nanoparticles without photosensitizers exposed to NIR laser.

Transportin-1-dependent YB-1 nuclear import

International Nuclear Information System (INIS)

Mordovkina, Daria A.; Kim, Ekaterina R.; Buldakov, Ilya A.; Sorokin, Alexey V.; Eliseeva, Irina A.; Lyabin, Dmitry N.; Ovchinnikov, Lev P.

2016-01-01

The DNA/RNA-binding protein YB-1 (Y-box binding protein 1) performs multiple functions both in the cytoplasm and the nucleus of the cell. Generally localized to the cytoplasm, under certain conditions YB-1 is translocated to the nucleus. Here we report for the first time a transport factor that mediates YB-1 nuclear import – transportin-1. The YB-1/transportin-1 complex can be isolated from HeLa cell extract. Nuclear import of YB-1 and its truncated form YB-1 (1-219) in in vitro transport assay was diminished in the presence of a competitor substrate and ceased in the presence of transportin-1 inhibitor M9M. Inhibitors of importin β1 had no effect on YB-1 transport. Furthermore, transport of YB-1 (P201A/Y202A) and YB-1 (1–219) (P201A/Y202A) bearing inactivating mutations in the transportin-1-dependent nuclear localization signal was practically abolished. Together, these results indicate that transportin-1 mediates YB-1 nuclear translocation. - Highlights: • Transportin-1 mediates YB-1 nuclear import. • YB-1 nuclear translocation is diminished in the presence of transportin-1 inhibitors. • Mutations in the PY motif of YB-1 NLS prevent its translocation to the nucleus.

Thermodynamic modeling of the Eu–Te and Te–Yb systems

Energy Technology Data Exchange (ETDEWEB)

Ghamri, H., E-mail: ghamri.houda@hotmail.fr; Djaballah, Y.; Belgacem-Bouzida, A.

2015-09-15

Highlights: • The Eu–Te and Te–Yb binary systems were not previously thermodynamically assessed. • The Eu–Te and Te–Yb systems were assessed by using the CALPHAD technique. • A coherent set of thermodynamic parameters was obtained for both systems. • An agreement between the calculated results and experimental data was obtained for both systems. - Abstract: In this work, thermodynamic assessments of the Eu–Te and Te–Yb binary systems were carried out by using the CALculation of PHase Diagrams (CALPHAD) method based on the available experimental data including thermodynamic properties and phase equilibria. Reasonable models were constructed for all the phases of the two systems. The liquid phases were described by the substitutional solution model with the Redlich–Kister polynomial. The three intermetallic compounds, Eu{sub 4}Te{sub 7}, Eu{sub 3}Te{sub 7} and TeYb in the two systems, were treated as stoichiometric phases, while the non-stoichiometric phase (EuTe), which has an homogeneity range, was treated by a two-sublattice model following the schema: (Eu,Te){sub 0.5}(Te){sub 0.5}. A consistent set of thermodynamic parameters leading to reasonable agreement between the calculated results and experimental data was obtained.

Local structure investigation of Ga and Yb dopants in Co4Sb12 skutterudites

Science.gov (United States)

Hu, Yanyun; Chen, Ning; Clancy, J. P.; Salvador, James R.; Kim, Chang-Yong; Shi, Xiaoya; Li, Qiang; Kim, Young-June

2017-12-01

We report comprehensive x-ray absorption spectroscopy studies at both the Ga K edge and Yb L2 edge to elucidate the local structure of Ga and Yb dopants in YbxGayCo4Sb12 . Our extended x-ray absorption fine structure (EXAFS) data confirm that Ga atoms occupy two crystallographic sites: one is the 24 g site replacing Sb, and the other is the 2 a site in the off-center void position. We find that the occupancy ratio of these two sites varies significantly as a function of the filling fraction of additional Yb, which exclusively occupies the 2 a on-center site. At low concentrations of Yb, Ga24 g and Ga2 a dopants coexist and they form a charge-compensated compound defect proposed by Qiu et al. [Adv. Funct. Mater. 23, 3194 (2013), 10.1002/adfm.201202571]. The Ga24 g occupancy increases gradually with increasing Yb concentration, and almost all Ga occupies the 24 g site for the highest Yb concentration studied (x =0.4 ). In addition to the local structural evidence provided by our EXAFS data, we also present x-ray absorption near-edge structure (XANES) spectra, which show a small Ga K -edge energy shift as a function of Yb concentration consistent with the change from predominantly Ga2 a to Ga24 g states. Our result suggests that the increased solubility of Yb in Yb-Ga co-doped Co4Sb12 skutterudites is due to the increased Ga24 g electron acceptor, and thus provides an important strategy to optimize the carrier concentration in partially filled skutterudites.

Moments of inertia in 162Yb at very high spins

International Nuclear Information System (INIS)

Simon, R.S.; Banaschik, M.V.; Colombani, P.; Soroka, D.P.; Stephens, F.S.; Diamond, R.M.

1976-01-01

Two methods have been used to obtain values of the effective moment of inertia of very-high-spin (20h-bar--50h-bar) states populated in heavy-ion compound-nucleus reactions. The 162 Yb nucleus studied has effective moments of inertia smaller than, but approaching, the rigid-body estimate

Electrochemistry and spectroelectrochemistry of tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine, Lu2Pc4 and dimeric lutetium(III) phthalocyanine, Lu2Pc2(OAc)2

International Nuclear Information System (INIS)

Koca, Atif; Ceyhan, Tanju; Erbil, Mehmet K.; Ozkaya, Ali Riza; Bekaroglu, Ozer

2007-01-01

In this study, electrochemical, electrochromic and spectroelectrochemical properties of a tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine (Lu 2 Pc 4 2) were investigated explicitly as compared with a tert-butylcalix[4]arene bridged dimeric lutetium(III) phthalocyanine [Lu 2 Pc 2 (OAc) 2 1]. Distinctive differences between electrochemical and electrochromic properties of 1 and 2 were detected. Moreover, the properties of 1 and 2 were compared with previously reported S 4 (CH 2 ) 4 bridged Lu 2 Pc 2 (OAc) 2 and Lu 2 Pc 4 . The calixarene bridged phthalocyanine (Pc) compounds, 1 and 2 showed well-defined electrochromic behaviour with green-blue and blue-purple colour transitions. The enhanced electrochromic properties of 2, as compared to 1, were attributed to its double-decker structure, probably allowing the formation of suitable ion channels for the counter ion movement in the solid film

New tetragonal derivatives of cubic NaZn13-type structure: RNi6Si6 compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd–Yb)

International Nuclear Information System (INIS)

Pani, M.; Manfrinetti, P.; Provino, A.; Yuan, Fang; Mozharivskyj, Y.; Morozkin, A.V.; Knotko, A.V.; Garshev, A.V.; Yapaskurt, V.O.; Isnard, O.

2014-01-01

Novel RNi 6 Si 6 compounds adopt the new CeNi 6 Si 6 -type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi 6 Si 6 -type structure for R=Y, Sm, Gd–Yb (tP52, space group P4 ¯ b2N 117) that are tetragonal derivative of NaZn 13 -type structure, like LaCo 9 Si 4 -type. The CeNi 6 Si 6 , GdNi 6 Si 6 , TbNi 6 Si 6 , DyNi 6 Si 6 and HoNi 6 Si 6 compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 5 K. However, the inverse paramagnetic susceptibility of LaNi 6 Si 6 does not follow Curie–Weiss law. The DyNi 6 Si 6 shows ferromagnetic-like saturation behaviour at 5 K in applied fields of 50 kOe, giving rise to a magnetic moment value of 6.5 μ B /f.u. in 50 kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi 6 Si 6 with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. - Graphical abstract: Novel (La, Ce)Ni 6 Si 6 compounds adopt the new CeNi 6 Si 6 -type structure and (Y, Sm, Gd–Yb) adopt the new YNi 6 Si 6 -type structure that are tetragonal derivative of NaZn 13 -type structure, like LaCo 9 Si 4 -type. The CeNi 6 Si 6 , GdNi 6 Si 6 , TbNi 6 Si 6 , DyNi 6 Si 6 and HoNi 6 Si 6 compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 4.2 K. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi 6 Si 6 with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. Display Omitted - Highlights: • The new (La, Ce)Ni 6 Si 6 compounds adopt the new CeNi 6 Si 6 -type structure. • The new (Y, Sm, Gd–Yb)Ni 6 Si 6 compounds adopt the new YNi 6 Si 6 -type structure. • TbNi 6 Si 6 has square modulated c-collinear antiferromagnetic ordering below ∼10 K

Electronic structures and superconductivity in LuTE2Si2 phases (TE = d-electron transition metal)

Science.gov (United States)

Samsel-Czekała, M.; Chajewski, G.; Wiśniewski, P.; Romanova, T.; Hackemer, A.; Gorzelniak, R.; Pikul, A. P.; Kaczorowski, D.

2018-05-01

In the course of our search for unconventional superconductors amidst the 1:2:2 phases, we have re-investigated the LuTE2Si2 compounds with TE = Fe, Co, Ni, Ru, Pd and Pt. In this paper, we present the results of our fully relativistic ab initio calculations of the band structures, performed using the full-potential local-orbital code. The theoretical data are supplemented by the results of low-temperature electrical transport and specific heat measurements performed down to 0.35 K. All the materials studied but LuPt2Si2 crystallize with the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm). Their Fermi surfaces exhibit a three-dimensional multi-band character. In turn, the Pt-bearing compound adopts the primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm), and its Fermi surface consists of predominantly quasi-two-dimensional sheets. Bulk superconductivity was found only in LuPd2Si2 and LuPt2Si2 (independent of the structure type and dimensionality of the Fermi surface). The key superconducting characteristics indicate a fully-gapped BCS type character. Though the electronic structure of LuFe2Si2 closely resembles that of the unconventional superconductor YFe2Ge2, this Lu-based silicide exhibits neither superconductivity nor spin fluctuations at least down to 0.35 K.

High-Pressure Synthesis and Characterization of the Ammonium Yttrium Borate (NH4)YB8O14.

Science.gov (United States)

Schmitt, Martin K; Podewitz, Maren; Liedl, Klaus R; Huppertz, Hubert

2017-11-20

The first high-pressure yttrium borate (NH 4 )YB 8 O 14 was synthesized at 12.8 GPa/1300 °C using a Walker-type multianvil module. The compound crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a = 17.6375(9), b = 10.7160(5), and c = 4.2191(2) Å. (NH 4 )YB 8 O 14 constitutes a novel structure type but exhibits similarities to the crystal structure of β-BaB 4 O 7 . X-ray single-crystal and powder diffraction, EDX, vibrational spectroscopy as well as quantum chemical calculations were used to characterize (NH 4 )YB 8 O 14 .

Fission fragment angular distribution in the reaction 28Si+176Yb

International Nuclear Information System (INIS)

Tripathi, R.; Sudarshan, K.; Sharma, S.K.; Reddy, A.V.R.; Pujari, P.K.; Dutta, D.; Goswami, A.; Ramachandran, K.

2009-01-01

Fission fragment angular distribution has been measured in the reaction 28 Si+ 176 Yb at beam energies of 145 and 155 MeV to investigate the contribution from non-compound nucleus fission. Experiments were carried out at BARC-TIFR Pelletron-LINAC accelerator facility, Mumbai. Experimental angular anisotropies in this reaction were observed to be higher than those calculated using statistical theory, indicating contribution from non-compound nucleus fission in this reaction. (author)

Synthesis of Halide- and Solvent free metal borohydrides

DEFF Research Database (Denmark)

Grinderslev, Jakob; Møller, Kasper Trans; Jensen, Torben René

chloride or LiBH4 is present in the sample. The synthesis pathway has been shown to work for most of the already known metal borohydrides, M = Na, Ca, Sr, Ba, Y, La, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb, but also new borohydrides are formed, M = Pr, Nd and Lu. Besides new compounds, new polymorphs...

RRh2Al10 (R = Ce, Yb): New intermetallic compounds in the 1 : 2 : 10 stoichiometry series

Science.gov (United States)

Strydom, A. M.; Djoumessi, R. F.; Blinova, M.; Tursina, A.; Nesterenko, S.; Avzuragova, V.

2018-05-01

The orthorhombic, space group Cmcm YbFe2Al10 structure type series of compounds are known to form with practically the entire series of rare-earth elements R, but only with the three d - electron elements Fe, Ru, and Os. The Ce-derivatives in particular have been of much interest since the first reports of their highly unusual physical properties. Classified as Kondo insulators, CeRu2Al10 and CeOs2Al10 controversially order magnetically and with uncharacteristically high Néel temperatures of ≃ 28 K. CeFe2Al10 on the other hand shows pronounced semiconducting and Kondo features but remains paramagnetic. As part of our ongoing studies into the rich physics of this class of materials we have succeeded in synthesizing new members of the 1:2:10 stoichiometry involving the chemical element Rh for the first time. CeRh2Al10 is found to crystallize in the tetragonal system with space group I41 / amd . Yb Rh2Al10 on the other hand forms in the serial Cmcm orthorhombic structure type. We discuss important similarities between the two types. At 5.310 Å the shortest Ce-Ce distance is, likewise to the situation in CeRu2Al10 and CeOs2Al10 , also well above the Hill limit of 3.40 Å. Despite the cage-like structure and large rare-earth separation distances, this study reveals the onset of long-range magnetic ordering in CeRh2Al10 at 3.9 K. The magnetic ordering develops out of an incoherent Kondo state that dominates the electrical resistivity below about 40 K.

Single-crystal structure refinement of YbF{sub 2} with a remark about YbH{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Reckeweg, Olaf; DiSalvo, Francis J. [Cornell Univ., Ithaca, NY (United States). Dept. of Chemistry and Chemical Biology

2017-07-01

Transparent-yellow single crystals of YbF{sub 2} were obtained as only crystalline product from the solid-state reaction of Yb and teflon designed to yield 'Yb{sub 3}C{sub 3}F{sub 2}' in addition to some amorphous black material. The first single-crystal structure determination of YbF{sub 2} (cubic space group Fm anti 3m, CaF{sub 2}-type structure, a = 559.46(16) pm; R1 = 1.2%, wR2 = 3.2%) was the starting point to compare isostructural binary fluorides MF{sub 2} and hydrides MH{sub 2} (M = Ca, Yb, Eu, Sr and Ba) exhibiting an as-yet unexplained small volume per formula unit for YbH{sub 2}.

The phase transition of the incommensurate phases β-Ln(PO3)3(Ln=Y,Tb…Yb), crystal structures of α-Ln(PO3)3(Ln=Y,Tb…Yb) and Sc(PO3)3

Science.gov (United States)

Höppe, Hennig A.

2009-07-01

The incommensurately modulated room-temperature phases β-Ln(PO3)3(Ln=Y,Tb…Yb) undergo a topotactic phase transition monitored by vibrational spectroscopy below 180 K leading to α-Ln(PO3)3(Ln=Y,Dy…Yb), above 200 K the incommensurate phases are reobtained. The low-temperature phases exhibit a new structure type (α-Dy(PO3)3, P21/c, Z=12,a=14.1422(6), b=20.0793(9),c=10.1018(4) A˚, β=127.532(3)∘). α-Tb(PO3)3 is isotypic with Gd(PO3)3(α-Tb(PO3)3, I2/a,Z=16,a=25.875(6), b=13.460(3), c=10.044(2) A˚, β=119.13(3)∘). The symmetry relations between the involved phases of the phase transition are discussed. The crystal structure of Sc(PO3)3 is isotypic with that of Lu(PO3)3 and C-type phosphates. The polyphosphates consist of infinite zig-zag chains of corner-sharing PO4 tetrahedra, the cations are coordinated sixfold in an almost octahedral arrangement. To confirm the quality of the determined crystal structures the deviation of the phosphate tetrahedra from ideal symmetry was determined and discussed.

Correlative theoretical and experimental investigation of the formation of AlYB_1_4 and competing phases

International Nuclear Information System (INIS)

Hunold, Oliver; Chen, Yen-Ting; Music, Denis; Baben, Moritz to; Achenbach, Jan-Ole; Keuter, Philipp; Schneider, Jochen M.; Persson, Per O. Å.; Primetzhofer, Daniel

2016-01-01

The phase formation in the boron-rich section of the Al-Y-B system has been explored by a correlative theoretical and experimental research approach. The structure of coatings deposited via high power pulsed magnetron sputtering from a compound target was studied using elastic recoil detection analysis, electron energy loss spectroscopy spectrum imaging, as well as X-ray and electron diffraction data. The formation of AlYB_1_4 together with the (Y,Al)B_6 impurity phase, containing 1.8 at. % less B than AlYB_1_4, was observed at a growth temperature of 800 °C and hence 600 °C below the bulk synthesis temperature. Based on quantum mechanical calculations, we infer that minute compositional variations within the film may be responsible for the formation of both icosahedrally bonded AlYB_1_4 and cubic (Y,Al)B_6 phases. These findings are relevant for synthesis attempts of all boron rich icosahedrally bonded compounds with the space group: Imma that form ternary phases at similar compositions.

Correlative theoretical and experimental investigation of the formation of AlYB{sub 14} and competing phases

Energy Technology Data Exchange (ETDEWEB)

Hunold, Oliver, E-mail: hunold@mch.rwth-aachen.de; Chen, Yen-Ting; Music, Denis; Baben, Moritz to; Achenbach, Jan-Ole; Keuter, Philipp; Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen (Germany); Persson, Per O. Å. [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden); Primetzhofer, Daniel [Department of Physics and Astronomy, Uppsala University, Lägerhyddsvägen 1, S-75120 Uppsala (Sweden)

2016-02-28

The phase formation in the boron-rich section of the Al-Y-B system has been explored by a correlative theoretical and experimental research approach. The structure of coatings deposited via high power pulsed magnetron sputtering from a compound target was studied using elastic recoil detection analysis, electron energy loss spectroscopy spectrum imaging, as well as X-ray and electron diffraction data. The formation of AlYB{sub 14} together with the (Y,Al)B{sub 6} impurity phase, containing 1.8 at. % less B than AlYB{sub 14}, was observed at a growth temperature of 800 °C and hence 600 °C below the bulk synthesis temperature. Based on quantum mechanical calculations, we infer that minute compositional variations within the film may be responsible for the formation of both icosahedrally bonded AlYB{sub 14} and cubic (Y,Al)B{sub 6} phases. These findings are relevant for synthesis attempts of all boron rich icosahedrally bonded compounds with the space group: Imma that form ternary phases at similar compositions.

Crystal field excitations of YbMn{sub 2}Si{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Mole, R.A. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia); School of Physical, Environmental and Mathematical Sciences, The University of New South Wales at the Australian Defence Force Academy, Canberra, ACT 2600 (Australia); Hofmann, M. [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales at the Australian Defence Force Academy, Canberra, ACT 2600 (Australia); Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, 85747 Garching (Germany); Adroja, D.T. [ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, OX11 OQX (United Kingdom); Moze, O. [Dipartimento di Fisica, Università degli Studi di Modena e Reggio Emilia, Modena (Italy); Campbell, S.J., E-mail: stewart.campbell@adfa.edu.au [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales at the Australian Defence Force Academy, Canberra, ACT 2600 (Australia)

2013-12-15

The crystal field excitations of the rare earth intermetallic compound YbMn{sub 2}Si{sub 2} have been measured by inelastic neutron scattering over the temperature range 2.5–50 K. The YbMn{sub 2}Si{sub 2} spectra exhibit three low energy excitations (∼3–7 meV) in the antiferromagnetic AFil region above the magnetic phase transition at T{sub N2} = 30(5) K. The crystal field parameters have been determined for YbMn{sub 2}Si{sub 2} in the antiferromagnetic AFil region. A further two inelastic excitations (∼9 meV, 17 meV) are observed below T{sub N2}=30(5) K, the temperature at which the high temperature antiferromagnetic structure is reported to exhibit doubling of the magnetic cell. Energy level diagrams have been determined for Yb{sup 3+} ions in the different sites above (single site) and below the magnetic transition temperature (two sites). The excitation energies for both sites are shown to be temperature independent with the temperature dependences of the transition intensities for the two sites described well by a simple Boltzmann model. The spectra below T{sub N2} cannot be described fully in terms of molecular field models based on either a single Yb{sup 3+} site or two Yb{sup 3+} sites. This indicates that the magnetic behaviour of YbMn{sub 2}Si{sub 2} is more complicated than previously considered. The inability to account fully for excitations below the magnetic phase transition may be due to an, as yet, unresolved structural transition associated with the magnetic transition. - Highlights: • The inelastic neutron scattering from YbMn{sub 2}Si{sub 2} has been investigated over the temperature range 2.5–50 K. • The crystal field splitting has been monitored through the magnetic transition at 30(5) K. • We have determined the crystal field parameters for the antiferromagnetic AFil region. • The transition intensities are described well by Boltzmann occupancy models. • The spectra below the magnetic transition have been analysed by

ThSi_2 type ytterbium disilicide and its analogues YbT_xSi_2_-_x (T = Cr, Fe, Co)

International Nuclear Information System (INIS)

Peter, Sebastian C.; Kanatzidis, Mercouri G.

2012-01-01

YbSi_2 and the derivatives YbT_xSi_2_-_x (T = Cr, Fe, Co) crystallizing in the α-ThSi_2 structure type were obtained as single crystals from reactions run in liquid indium. All silicides were investigated by single-crystal X-ray diffraction, I4_1/amd space group and the lattice constants are: a = 3.9868(6) Aa and c = 13.541(3) Aa for YbSi_2, a = 4.0123(6) Aa and c = 13.542(3) Aa for YbCr_0_._2_7Si_1_._7_3, a = 4.0142(6) Aa and c = 13.830(3) Aa for YbCr_0_._7_1Si_1_._2_9, a = 4.0080(6) Aa and c = 13.751(3) Aa for YbFe_0_._3_4Si_1_._6_6, and a = 4.0036(6) Aa, c = 13.707(3) Aa for YbCo_0_._2_1Si_1_._7_9. YbSi_2 and YbT_xSi_2_-_x compounds are polar intermetallics with three-dimensional Si and M (T+Si) polyanion sub-networks, respectively, filled with ytterbium atoms. The degree of substitution of transition metal at the silicon site is signficant and leads to changes in the average bond lengths and bond angles substantially. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Functional conservation of rice OsNF-YB/YC and Arabidopsis AtNF-YB/YC proteins in the regulation of flowering time

KAUST Repository

Hwang, Yoon-Hyung; Kim, SoonKap; Lee, Keh Chien; Chung, Young Soo; Lee, Jeong Hwan; Kim, Jeong-Kook

2016-01-01

Plant NUCLEAR FACTOR Y (NF-Y) transcription factors play important roles in plant development and abiotic stress. In Arabidopsis thaliana, two NF-YB (AtNF-YB2 and AtNF-YB3) and five NF-YC (AtNF-YC1, AtNF-YC2, AtNF-YC3, AtNF-YC4, and AtNF-YC9) genes regulate photoperiodic flowering by interacting with other AtNF-Y subunit proteins. Three rice NF-YB (OsNF-YB8, OsNF-YB10, and OsNF-YB11) and five rice OsNF-YC (OsNF-YC1, OsNF-YC2, OsNF-YC4, OsNF-YC6, and OsNF-YC7) genes are clustered with two AtNF-YB and five AtNF-YC genes, respectively. To investigate the functional conservation of these NF-YB and NF-YC genes in rice and Arabidopsis, we analyzed the flowering phenotypes of transgenic plants overexpressing the respective OsNF-YB and OsNF-YC genes in Arabidopsis mutants. Overexpression of OsNF-YB8/10/11 and OsNF-YC2 complemented the late flowering phenotype of Arabidopsis nf-yb2 nf-yb3 and nf-yc3 nf-yc4 nf-yc9 mutants, respectively. The rescued phenotype of 35S::OsNF-YC2 nf-yc3 nf-yc4 nf-yc9 plants was attributed to the upregulation of FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). In vitro and in planta protein–protein analyses revealed that OsNF-YB8/10/11 and OsNF-YC1/2/4/6/7 interact with AtNF-YC3/4/9 and AtNF-YB2/3, respectively. Our data indicate that some OsNF-YB and OsNF-YC genes are functional equivalents of AtNF-YB2/3 and AtNF-YC3/4/9 genes, respectively, and suggest functional conservation of Arabidopsis and rice NF-Y genes in the control of flowering time.

Functional conservation of rice OsNF-YB/YC and Arabidopsis AtNF-YB/YC proteins in the regulation of flowering time

KAUST Repository

Hwang, Yoon-Hyung

2016-01-11

Plant NUCLEAR FACTOR Y (NF-Y) transcription factors play important roles in plant development and abiotic stress. In Arabidopsis thaliana, two NF-YB (AtNF-YB2 and AtNF-YB3) and five NF-YC (AtNF-YC1, AtNF-YC2, AtNF-YC3, AtNF-YC4, and AtNF-YC9) genes regulate photoperiodic flowering by interacting with other AtNF-Y subunit proteins. Three rice NF-YB (OsNF-YB8, OsNF-YB10, and OsNF-YB11) and five rice OsNF-YC (OsNF-YC1, OsNF-YC2, OsNF-YC4, OsNF-YC6, and OsNF-YC7) genes are clustered with two AtNF-YB and five AtNF-YC genes, respectively. To investigate the functional conservation of these NF-YB and NF-YC genes in rice and Arabidopsis, we analyzed the flowering phenotypes of transgenic plants overexpressing the respective OsNF-YB and OsNF-YC genes in Arabidopsis mutants. Overexpression of OsNF-YB8/10/11 and OsNF-YC2 complemented the late flowering phenotype of Arabidopsis nf-yb2 nf-yb3 and nf-yc3 nf-yc4 nf-yc9 mutants, respectively. The rescued phenotype of 35S::OsNF-YC2 nf-yc3 nf-yc4 nf-yc9 plants was attributed to the upregulation of FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). In vitro and in planta protein–protein analyses revealed that OsNF-YB8/10/11 and OsNF-YC1/2/4/6/7 interact with AtNF-YC3/4/9 and AtNF-YB2/3, respectively. Our data indicate that some OsNF-YB and OsNF-YC genes are functional equivalents of AtNF-YB2/3 and AtNF-YC3/4/9 genes, respectively, and suggest functional conservation of Arabidopsis and rice NF-Y genes in the control of flowering time.

Preparation, thermogravimetric study and infrared spectra of rare earth acetates

International Nuclear Information System (INIS)

Graehlert, X.; Starke, M.

1992-01-01

The anhydrous and the hydrated acetates of Ho, Er, Tm, Yb and Lu have been prepared. The compounds obtained have been investigated by thermogravimetric analysis and infrared spectroscopy. The thermal decomposition of the rare earth acetates may proceed via various steps. It depends on both the number of crystal water molecules in the acetates and the rare earth element's behaviour. (orig.)

Rare-earth metal compounds with a novel ligand 2-methoxycinnamylidenepyruvate: A thermal and spectroscopic approach

Energy Technology Data Exchange (ETDEWEB)

Carvalho, C.T., E-mail: claudiocarvalho@ufgd.edu.br [Federal University of Grande Dourados, UFGD, 79.804-970 Dourados, MS (Brazil); Oliveira, G.F. [Federal University of Grande Dourados, UFGD, 79.804-970 Dourados, MS (Brazil); Fernandes, J. [Federal University of Grande Dourados, UFGD, 79.804-970 Dourados, MS (Brazil); Federal University of Mato Grosso, UFMT, 78.060-900 Cuiabá, MT (Brazil); Federal University of Goiás, UFG, 74.690-900, Goiânia, GO (Brazil); Institute of Chemistry, UNESP, 14.801-970 Araraquara, SP (Brazil); Siqueira, A.B. [Federal University of Mato Grosso, UFMT, 78.060-900 Cuiabá, MT (Brazil); Ionashiro, E.Y. [Federal University of Goiás, UFG, 74.690-900, Goiânia, GO (Brazil); Ionashiro, M. [Institute of Chemistry, UNESP, 14.801-970 Araraquara, SP (Brazil)

2016-08-10

Highlights: • 2-Methoxycinnamylidenepyruvate as a novel ligand for the synthesis of complexes. • Complexes with well-defined structural arrangements. • Thermal decomposition dependent on the nature of the metal ion. • Study by TG/FT-IR and TG/MS of the gaseous products released. • Potential technological application. - Abstract: Compounds of 2-methoxycinnamylidenepyruvate with trivalent lanthanide ions (Tb, Ho, Er, Tm, Yb and Lu) were obtained in solid state and studied mainly in terms of their thermal and spectroscopic properties. The analyses of the characterization were performed by thermogravimetric system coupled to a mass and infrared spectrometer (TG–DTA/MS and TG–DTA/FT-IR), X-ray powder diffractometry, differential scanning calorimetry (DSC), infrared (FT-IR), preliminary study of fluorescence as well as classical technique of titration with EDTA. From these results, it was possible to establish the stoichiometry, thermal behavior, hydration water content, and the gaseous products released in the thermal decomposition steps, and suggest the type of metal-ligand coordination.

Magnetic behavior of the nanophase of YbNi2 alloys

Science.gov (United States)

Ivanshin, V. A.; Gataullin, E. M.; Sukhanov, A. A.; Ivanshin, N. A.; Rojas, D. P.; Fernández Barquín, L.

2017-04-01

Variations in magnetic properties of the heavy-fermion YbNi2 alloy when milled in a high energy ball milling system have been investigated. The ferromagnetic transition ( T C = 10.4 K) in the initial sample almost vanishes after milling, which leads to the appearance of a magnetic transition at T* = 3.2 K in nanocrystallites. Before milling, processes of spin-lattice relaxation of the Orbach-Aminov type with the participation of the first excited Stark sublevel of the Yb3+ ion located at 75 K are dominating in the electron spin dynamics in the paramagnetic phase of the alloy. A comparative study of the temperature dependence of the magnetic properties and spectra of electron paramagnetic resonance in poly- and nanocrystalline samples indicates the existence of a magnetic inhomogeneity of the compound arising upon milling.

Valence and Magnetic Transitions in YbMn2Ge2-Applied Pressure

International Nuclear Information System (INIS)

Hofmann, M.; Link, P.; Campbell, S.J.; Goncharenko, I.

2005-01-01

Full text: Rare-earth intermetallic compounds containing ytterbium exhibit a wide range of interesting and unusual physical and magnetic properties. This occurs mainly as a result of their mixed valence states (II/III) or changes from one valence state to the other. We have recently determined the magnetic structures of tetragonal YbMn 2 Ge 2 (I4/mmm) by powder neutron diffraction experiments and demonstrated that YbMn 2 Ge 2 has a planar antiferromagnetic structure below T N1 ∼ 510 K with a canted antiferromagnetic structure below T N2 ∼ 185 K. As applied pressure favours changes in the valence character of intermediate valence systems and correspondingly influences the magnetic behaviour, we have investigated the effects of applied pressure on YbMn 2 Ge 2 . Analyses of our in situ neutron diffraction experiments (T=1.5-300 K; p=0-2.7 GPa), reveal a distinct change in magnetic structure and a sharp drop in the a-lattice parameter above ∼ 1.4 GPa with the changes associated with a valence transition. A full account of these effects will be discussed in relation to our current photoelectron spectroscopy measurements of YbMn 2 Ge 2 . (authors)

NIR to visible frequency upconversion in Er3+ and Yb3+ codoped ZrO2 phosphor

International Nuclear Information System (INIS)

Singh, Vijay; Kim, Sang Hwan; Rai, Vineet Kumar; Al-Shamery, Katharina; Haase, Markus

2013-01-01

The ZrO 2 :Er 3+ codoped with Yb 3+ phosphor powders have been prepared by the urea combustion route. Formation of the compounds ZrO 2 :Er 3+ and ZrO 2 :Er 3+ , Yb 3+ was confirmed by XRD. The frequency upconversion emissions in the green and red regions upon excitation with a CW diode laser at ∝978 nm are reported. Codoping with Yb 3+ enhances the emission intensities of the triply ionized erbium in the green and red spectral regions by about ∝130 and ∝820 times respectively. The emission properties of the ZrO 2 :Er 3+ phosphor powders are discussed on the basis of excited state absorption, energy transfer, and cross-relaxation energy transfer mechanisms. (orig.)

Radio metal (169Yb) uptake in normal and tumour cells in vitro. Influence of metabolic cell activity and complex structure

International Nuclear Information System (INIS)

Franke, W.G.; Kampf, G.

1996-01-01

Trivalent radio metal tracers have been used for tumour imaging and metastatic pain palliation. For better understanding their tumour accumulation, basic model studies of uptake of different 169 Yb complexes into cultured normal and tumour cells were performed. Whereas the uptake of 169 Yb citrate is strongly dependent on the metabolic activity and is not tumour-cell pacific, the uptake of 169 Yb complexed with amino carbonic acid (NTA, EDTA, DTPA) does not correlate to the metabolic activities. These complexes are taken up to a greater amount by the tumour cells (by a factor of about 2). Uptake of both complex types leads to a stable association to cellular compounds, 169 Yb is not releasable by the strong complexing agent DTPA. Protein binding of the 169 Yb complexes shows great influence on their cellular uptake. The bound proportion is no more available,for cellular uptake. The results indicate that i 0 uptake of 169 Yb citrate is an active cellular transport process which i not tumor-specific, ii) the 169 Yb amino carbonic acid complexes show a weak favouring by the tumour cells, iii) different from earlier acceptions the Yb complexes studied are not taken up by the cells in protein-bound form. The structure of the Yb complex is decisive for its protein binding and cellular uptake. (author). 13 refs., 6 figs

CW laser properties of Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG mixed crystals

Science.gov (United States)

Di, J. Q.; Xu, X. D.; Li, D. Z.; Zhou, D. H.; Wu, F.; Zhao, Z. W.; Xu, J.; Tang, D. Y.

2011-10-01

Three mixed crystals, Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG, were grown by Czochralski method. We report the continuous-wave (CW) Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG laser operation under laser diode pumping. The maximum output powers are 4.11, 5.31, and 7.47 W, with slope efficiency of 73.0, 55.3, and 57.1%, respectively. With replacing Lu3+ or Y3+ ions with large Gd3+ ions, the pump efficiency increases.

Pressure-induced valence and structure change in some anti-Th3P4 structure rare earth compounds

International Nuclear Information System (INIS)

Werner, A.; Hochheimer, H.D.; Jayaraman, A.; Bucher, E.

1981-01-01

The anti-Th 3 P 4 structure compounds Yb 4 Bi 3 and Yb 4 Sb 3 have been investigated to 350 kbar by high pressure X-ray diffraction, using the diamond anvil cell. From the P-V data it is found that Yb 4 Bi 3 and Yb 4 Sb 3 are much more compressible, compared to Sm 4 Bi 3 before the valence transition. This suggests that a continuous change in the valence state of Yb takes place with pressure in the two compounds and that they may be in the mixed valent state already at ambient pressure. The ''collapsed'' anti-Th 3 P 4 structure becomes unstable in Yb 4 Bi 3 and Yb 4 Sb 3 and new lines appear at high pressure, that fit the NaCl structure. The latter structure change seems to occur also in the electronically collapsed Sm 4 Bi 3 . The results are presented and discussed. (Auth.)

Contribution to the study of deformed heavy nuclei by means of nuclear reactions; Contribution a l'etude des noyaux lourds deformes au moyen de reactions nucleaires

Energy Technology Data Exchange (ETDEWEB)

Gastebois, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-06-01

The experimental results obtained in the study of the (d,p) reactions, at E{sub d} = 12 MeV, on the three even-even deformed nuclei {sup 170}Yb, {sup 172}Yb and {sup 174}Yb have been analysed in terms of DWBA calculations. The spectroscopic information relative to the odd final nuclei have been compared with the predictions of the collective model and of the Nilsson's model. The effect of various parameters used in the DWBA analysis (form factors, optical wave functions) has been carefully studied. The observed differences between the three final nuclei are qualitatively reproduced in the experimental study of resonances, seen in excitation functions of elastically and inelastically scattered protons on the same target nuclei, and corresponding to analogue states in the three nuclei {sup 171}Lu, {sup 173}Lu and {sup 175}Lu. (author) [French] Les resultats experimentaux de l'etude des reactions (d.p) a E{sub d} = 12 MeV, sur les noyaux deformes pairs-pairs {sup 170}Yb, {sup 172}Yb et {sup 174}Yb ont ete interpretes dans le cadre de l'approximation de Born des ondes deformees. Les informations spectroscopiques relatives aux noyaux impairs finals ont ete comparees aux predictions du modele collectif et du modele de Nilsson, apres avoir examine avec soin l'influence des differents parametres (facteurs de forme, fonctions d'onde 'optiques') utilises lors de l'analyse. Les differences observees entre les trois noyaux finals sont qualitativement reproduites par les resultats experimentaux de l'etude de resonances dans les fonctions d'excitation de diffusion elastique et inelastique de protons sur les memes noyaux-cibles, lors de la recherche d'etats analogues dans les noyaux {sup 171}Lu, {sup 173}Lu et {sup 175}Lu. (auteur)

Production of isomers in compound and transfer reactions with 4He ions

International Nuclear Information System (INIS)

Karamyan, S.A.; Aksenov, N.V.; Albin, Yu.A.; Bozhikov, G.A.; Dmitriev, S.N.; Starodub, G.Ya.; Vostokin, G.K.; Carroll, J.J.

2011-01-01

A well-known island of nuclear isomerism appears near A = 175-180 due to the deformation alignment of single-particle orbits at high angular momentum. This sometimes results in the formation of multi-quasiparticle states with record spin that are long-lived because of 'K-hindrance', i.e., symmetry rearrangement. Production methods and spectroscopic studies of these isomers remain a challenge for modern nuclear reaction and nuclear structure physics. Activities were produced by irradiation of 176 Yb(97.6%) enriched and nat Lu targets with 35-MeV 4 He ions from the internal beam of the U200 cyclotron. Induced activities were analyzed applying methods of radiochemistry and gamma spectroscopy. Yields of compound and nucleon-transfer reactions were measured and the isomer-to-ground state ratios were deduced. Calculated results were obtained using standard procedures to reproduce the (α, xn) cross sections, and the systematic behavior of the nucleon-transfer yields was established. The isomer-to-ground state ratios for direct reactions with 4 He ions were examined, resulting in a new characterization of the reaction mechanism

Memories of Lu Jingqing

Institute of Scientific and Technical Information of China (English)

1994-01-01

Lu Jingqing was a woman of letters who wrote poems when she was young and also worked as an editor and teacher. Her main works are Women poets of the Tang Dynasty (1931), Whisper (a collection of poems, 1932), Plain Writing (a collection of verses, 1930) and The Wandering (1933). In March 1993, 86-year-old Lu Jingqing, Professor of the Shanghai College of Finance and Economics, died in Shanghai. Zhu Bokang, an old friend of Lu and her husband wrote the following article in her memory.

Structural and Magnetothermal Properties of Compounds: Yb₅Si_xGe_4-x,Sm₅Si_xGe_4-x, EuO, and Eu₃O₄

Energy Technology Data Exchange (ETDEWEB)

Ahn, Kyunghan [Iowa State Univ., Ames, IA (United States)

2007-01-01

The family of R₅Si_xGe_4-x alloys demonstrates a variety of unique physical phenomena related to magneto-structural transitions associated with reversible breaking and reforming of specific bonds that can be controlled by numerous external parameters such as chemical composition, magnetic field, temperature, and pressure. Therefore, R₅Si_xGe_4-x systems have been extensively studied to uncover the mechanism of the extraordinary magneto-responsive properties including the giant magnetoresistance (GMR) and colossal magnetostriction, as well as giant magnetocaloric effect (GMCE). Until now, more than a half of possible R₅Si_xGe_4-x pseudobinary systems have been completely or partially investigated with respect to their crystallography and phase relationships (R = La, Pr, Nd, Gd, Tb, Dy, Er, Lu, Y). Still, there are other R₅Si_xGe_4-x systems (R = Ce, Sm, Ho, Tm, and Yb) that are not studied yet. Here, we report on phase relationships and structural, magnetic, and thermodynamic properties in the Yb₅Si_xGe_4-xand Sm₅Si_xGe_4-x pseudobinary systems, which may exhibit mixed valence states. The crystallography, phase relationships, and physical properties of Yb₅Si_xGe_4-x alloys with 0 ≤ x ≤ 4 have been examined by using single crystal and powder x-ray diffraction at room temperature, and dc magnetization and heat capacity measurements between 1.8 K and 400 K in magnetic fields ranging from 0 to 7 T. Unlike the majority of R₅Si_xGe_4-x systems studied to date, where R is the rare earth metal, all Yb-based germanide-silicides with the 5:4 stoichiometry crystallize in the same Gd₅Si₄-type structure. The magnetic properties of Yb₅Si_xGe_4-x materials are nearly composition

Cationic Site-Preference in the Yb14-xCaxAlSb11 (4.81 ≤ x ≤ 10.57 Series: Theoretical and Experimental Studies

Directory of Open Access Journals (Sweden)

Gnu Nam

2016-07-01

Full Text Available Four quaternary Zintl phases with mixed-cations in the Yb14-xCaxAlSb11 (4.81 ≤ x ≤ 10.57 series have been synthesized by using the arc-melting and the Sn metal-flux reaction methods, and the isotypic crystal structures of the title compounds have been characterized by both powder and single-crystal X-ray diffraction (PXRD and SXRD analyses. The overall crystal structure adopting the Ca14AlSb11-type can be described as a pack of four different types of the spiral-shaped one-dimensional octahedra chains with various turning radii, each of which is formed by the distorted ((Yb/CaSb6 octahedra. Four symmetrically-independent cationic sites contain mixed occupations of Yb2+ and Ca2+ with different mixing ratios and display a particular site preference by two cationic elements. Two hypothetical structural models of Yb4Ca10AlSb11 with different cationic arrangements were designed and exploited to study the details of site and bond energies. QVAL values provided the rationale for the observed site preference based on the electronegativity of each atom. Density of states (DOS curves indicated a semiconducting property of the title compounds, and crystal orbital Hamilton population (COHP plots explained individual chemical bonding between components. Thermal conductivity measurement was performed for Yb8.42(4Ca5.58AlSb11, and the result was compared to compounds without mixed cations.

Spectrographic determination of some rare earths in thorium compounds

International Nuclear Information System (INIS)

Brito, J. de.

1977-01-01

A method for spectrographic determination of Gd, Sm, Dy, Eu, Y, Yb, Tm and Lu in thorium compounds has been developed. Sensibilities of 0.01 μg rare earths/g Th02 were achieved. The rare earth elements were chromatographycally separated in a nitric acid-ether-cellulose system. The solvent mixture was prepared by dissolving 11% of concentrated nitric acid in ether. The method is based upon the sorption of the rare earths on activated cellulose, the elements being eluted together with 0.01 M HNO 3 . The retention of the 152 , 154 Eu used as tracer was 99,4%. The other elements showed recoveries varying from 95 to 99%. A direct carrier destillation procedure for the spectrochemical determination of the mentioned elements was used. Several concentrations of silver chloride were used to study the volatility behavior of the rare earths. 2%AgCl was added to the matrix as definite carrier, being lantanum selected as internal standard. The average coefficient of variation for this method was +- -+ 7%. The method has been appleid to the analysis of rare earths in thorium coumpounds prepared by Thorium Purification Pilot Plant at Atomic Energy Institute, Sao Paulo [pt

Discovery of 1-[2-(2,4-dimethylphenylsulfanyl)phenyl]piperazine (Lu AA21004): a novel multimodal compound for the treatment of major depressive disorder.

Science.gov (United States)

Bang-Andersen, Benny; Ruhland, Thomas; Jørgensen, Morten; Smith, Garrick; Frederiksen, Kristen; Jensen, Klaus Gjervig; Zhong, Huailing; Nielsen, Søren Møller; Hogg, Sandra; Mørk, Arne; Stensbøl, Tine Bryan

2011-05-12

The synthesis and structure-activity relationship of a novel series of compounds with combined effects on 5-HT(3A) and 5-HT(1A) receptors and on the serotonin (5-HT) transporter (SERT) are described. Compound 5m (Lu AA21004) was the lead compound, displaying high affinity for recombinant human 5-HT(1A) (K(i) = 15 nM), 5-HT(1B) (K(i) = 33 nM), 5-HT(3A) (K(i) = 3.7 nM), 5-HT(7) (K(i) = 19 nM), and noradrenergic β(1) (K(i) = 46 nM) receptors, and SERT (K(i) = 1.6 nM). Compound 5m displayed antagonistic properties at 5-HT(3A) and 5-HT(7) receptors, partial agonist properties at 5-HT(1B) receptors, agonistic properties at 5-HT(1A) receptors, and potent inhibition of SERT. In conscious rats, 5m significantly increased extracellular 5-HT levels in the brain after acute and 3 days of treatment. Following the 3-day treatment (5 or 10 (mg/kg)/day) SERT occupancies were only 43% and 57%, respectively. These characteristics indicate that 5m is a novel multimodal serotonergic compound, and 5m is currently in clinical development for major depressive disorder.

Genome-wide analysis of the human Alu Yb-lineage

Directory of Open Access Journals (Sweden)

Carter Anthony B

2004-03-01

Full Text Available Abstract The Alu Yb-lineage is a 'young' primarily human-specific group of short interspersed element (SINE subfamilies that have integrated throughout the human genome. In this study, we have computationally screened the draft sequence of the human genome for Alu Yb-lineage subfamily members present on autosomal chromosomes. A total of 1,733 Yb Alu subfamily members have integrated into human autosomes. The average ages of Yb-lineage subfamilies, Yb7, Yb8 and Yb9, are estimated as 4.81, 2.39 and 2.32 million years, respectively. In order to determine the contribution of the Alu Yb-lineage to human genomic diversity, 1,202 loci were analysed using polymerase chain reaction (PCR-based assays, which amplify the genomic regions containing individual Yb-lineage subfamily members. Approximately 20 per cent of the Yb-lineage Alu elements are polymorphic for insertion presence/absence in the human genome. Fewer than 0.5 per cent of the Yb loci also demonstrate insertions at orthologous positions in non-human primate genomes. Genomic sequencing of these unusual loci demonstrates that each of the orthologous loci from non-human primate genomes contains older Y, Sg and Sx Alu family members that have been altered, through various mechanisms, into Yb8 sequences. These data suggest that Alu Yb-lineage subfamily members are largely restricted to the human genome. The high copy number, level of insertion polymorphism and estimated age indicate that members of the Alu Yb elements will be useful in a wide range of genetic analyses.

Synthesis and characterization of Yb and Er based monosilicate powders and durability of plasma sprayed Yb2SiO5 coatings on C/C–SiC composites

International Nuclear Information System (INIS)

Khan, Zuhair S.; Zou Binglin; Huang Wenzhi; Fan Xizhi; Gu Lijian; Chen Xiaolong; Zeng Shuibing; Wang Chunjie; Cao Xueqiang

2012-01-01

Highlights: ► Ultra-pure rare-earth monosilicate powders based on Er and Yb have been fabricated by solid-state reaction. ► Spray-drying treatment results in powders with free flowing characteristics and rounded surface morphologies. ► CTEs are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 . ► Plasma spraying has been used to deposit Yb 2 SiO 5 coatings on C/C–SiC substrate. ► Coatings remain strongly intact with the substrate on thermal cycling between ∼400 °C and 1500 °C in gas burner rig experiment. - Abstract: Rare-earth silicates such as Yb 2 SiO 5 and Er 2 SiO 5 are promising environmental barrier coating materials for ceramic matrix composites. In this work, Yb 2 SiO 5 and Er 2 SiO 5 ceramic powders have been synthesized by solid-state reaction using Yb 2 O 3 , Er 2 O 3 and SiO 2 as starting materials. The fabricated powders were subjected to spray drying treatment for subsequent synthesis of coatings by plasma spraying. The spray drying resulted in well-dispersed and spherical powder particles with good flowability. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry and differential scanning calorimetry (TGA/DSC) and dilatometry were applied to study the microstructural and thermal characteristics of the powders. Ultra-high purity monosilicate powders formed as a result of heating treatments at 1400 °C in a box furnace for 20 h. TG/DSC revealed the genesis temperatures of the silicate formation (low temperature polymorphs) and also showed that the solid-state reactions to form Yb and Er based monosilicates proceeded without any weight-loss in the tested temperature range. The values of coefficients of thermal expansion (CTE) of the fabricated compounds are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 by dilatometric measurements. Besides these studies, coating formation by plasma spraying of spray-dried Yb 2 SiO 5 powders on the ceramic

Are there non-statistical effects in /sup 173/Yb(n,gamma)/sup 174/Yb?

International Nuclear Information System (INIS)

Pospisil, S.; Becvar, F.; Chrien, R.E.; Kopecky, J.

1987-01-01

The resonance-averaged capture of neutrons in 173 Yb has been studied at energy of 2 keV. With a statistical significance of 99.5% an enhancement of E1-transition to the neutron 2QP levels in 174 Yb is observed. 8 refs

Magnetic interactions in rhenium-containing rare earth double perovskites Sr{sub 2}LnReO{sub 6} (Ln=rare earths)

Energy Technology Data Exchange (ETDEWEB)

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

2017-04-15

The perovskite-type compounds containing both rare earth and rhenium Sr{sub 2}LnReO{sub 6} (Ln=Y, Tb-Lu) have been prepared. Powder X-ray diffraction measurements and Rietveld analysis show that Ln{sup 3+} and Re{sup 5+} ions are structurally ordered at the B site of the perovskite SrBO{sub 3}. Magnetic anomalies are found in their magnetic susceptibility and specific heat measurements at 2.6–20 K for Ln=Y, Tb, Dy, Yb, Lu compounds. They are due to magnetic interactions between Re{sup 5+} ions. The results of the magnetic hysteresis and remnant magnetization measurements for Sr{sub 2}YReO{sub 6} and Sr{sub 2}LuReO{sub 6} indicate that the antiferromagnetic interactions between Re{sup 5+} ions below transition temperatures have a weak ferromagnetic component. The analysis of the magnetic specific heat data for Sr{sub 2}YbReO{sub 6} shows that both the Yb{sup 3+} and Re{sup 5+} ions magnetically order at 20 K. For the case of Sr{sub 2}DyReO{sub 6}, magnetic ordering of the Re{sup 5+} moments occurs at 93 K, and with decreasing temperature, the moments of Dy{sup 3+} ferromagnetically order at 5 K from the measurements of magnetic susceptibility and specific heat. - Graphical abstract: Crystal structure of double perovskite Sr{sub 2}LnReO{sub 6}. Red and black lines show cubic and monoclinic unit cells, respectively. - Highlights: • Double perovskites Sr{sub 2}LnReO{sub 6} (Ln=rare earths) were prepared. • They show an antiferromagnetic transition at 2.6–20 K. • In Sr{sub 2}DyReO{sub 6}, Dy and Re moments magnetically order at 5 and 93 K, respectively.

Peculiarity of component interaction in {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems

Energy Technology Data Exchange (ETDEWEB)

Romaka, V.V. [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Konyk, M. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Romaka, L., E-mail: romakal@franko.lviv.ua [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Pavlyuk, V. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Jan Dlugosz University, Institute of Chemistry, Environmental Protection and Biotechnology, al. Armii Krajowej 13/15, 42200 Czestochowa (Poland); Ehrenberg, H. [Institute for Complex Materials, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden (Germany); Tkachuk, A. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine)

2011-07-14

Highlights: > {l_brace}Y, Dy{r_brace}-Mn-Sn ternary systems at 770 K are characterized by formation of stannides with general compositions RMn{sub 6}Sn{sub 6} and R{sub 4}Mn{sub 4}Sn{sub 7}. > The crystal structure of YMn{sub 6}Sn{sub 6} was determined by single crystal and powder diffraction methods. > Structural analysis showed that Dy{sub 4}Mn{sub 4}Sn{sub 7} compound is disordered. > Isostructural R{sub 4}Mn{sub 4}Sn{sub 7} compounds were also found with Gd, Tb, Ho, Er, Tm(confirmed), Yb, and Lu. - Abstract: The phase equilibria in the Y-Mn-Sn and Dy-Mn-Sn ternary systems were studied at 770 K by means of X-ray and metallographic analyses in the whole concentration range. Both Y-Mn-Sn and Dy-Mn-Sn systems are characterized by formation of two ternary compounds RMn{sub 6}Sn{sub 6} (MgFe{sub 6}Ge{sub 6}-type, space group P6/mmm) and R{sub 4}Mn{sub 4}Sn{sub 7} (Zr{sub 4}Co{sub 4}Ge{sub 7}-type, space group I4/mmm). The disorder in Dy{sub 4}Mn{sub 4}Sn{sub 7} compound was found by single crystal method. Compounds with the same type of structure were also found with Gd, Tb, Ho, Er, Tm (confirmed), Yb, and Lu and their lattice parameters were determined.

Growth and laser action of Yb: YVO4 crystals with low Yb doping concentration

Science.gov (United States)

Zhong, Degao; Teng, Bing; Li, Jianhong; Zhang, Shiming; Zhang, Bingtao; Wang, Chao; Tian, Xueping; Liu, Junhai

2012-11-01

Yb: YVO4 single crystals with low doping concentrations of Yb3+ less than 0.3 at% were grown using the Czochralski method. The polarized absorption spectra were measured at room temperature. Strong anisotropy exists in the absorption spectra, resulting in almost entirely different features for π-polarization and σ-polarization. The laser emission spectrum and relationship curve between the output power and absorbed pump power (Pabs) were measured. The continuous-wave laser action of Yb: YVO4 single crystal in a range of 1020.4-1026.3 nm was realized by using a high-power diode laser as the pump source.

The phase transition of the incommensurate phases β-Ln(PO3)3(Ln=Y,Tb...Yb), crystal structures of α-Ln(PO3)3(Ln=Y,Tb...Yb) and Sc(PO3)3

International Nuclear Information System (INIS)

Hoeppe, Hennig A.

2009-01-01

The incommensurately modulated room-temperature phases β-Ln(PO 3 ) 3 (Ln=Y,Tb...Yb) undergo a topotactic phase transition monitored by vibrational spectroscopy below 180 K leading to α-Ln(PO 3 ) 3 (Ln=Y,Dy...Yb), above 200 K the incommensurate phases are reobtained. The low-temperature phases exhibit a new structure type (α-Dy(PO 3 ) 3 ,P2 1 /c,Z=12,a=14.1422(6),b=20.0793(9),c=10.1018(4)A, β=127.532(3) 0 ). α-Tb(PO 3 ) 3 is isotypic with Gd(PO 3 ) 3 (α-Tb(PO 3 ) 3 ,I2/a,Z=16,a=25.875(6),b=13.460(3),c=10.044(2)A, β=119.13(3) 0 ). The symmetry relations between the involved phases of the phase transition are discussed. The crystal structure of Sc(PO 3 ) 3 is isotypic with that of Lu(PO 3 ) 3 and C-type phosphates. The polyphosphates consist of infinite zig-zag chains of corner-sharing PO 4 tetrahedra, the cations are coordinated sixfold in an almost octahedral arrangement. To confirm the quality of the determined crystal structures the deviation of the phosphate tetrahedra from ideal symmetry was determined and discussed. - Abstract: Basic structure from which all crystal structures of the late lanthanoids' polyphosphates at room temperature and below can be derived.

Electrochemistry and spectroelectrochemistry of tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine, Lu{sub 2}Pc{sub 4} and dimeric lutetium(III) phthalocyanine, Lu{sub 2}Pc{sub 2}(OAc){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Koca, Atif [Chemical Engineering Department, Engineering Faculty, Marmara University, TR34722 Goeztepe, Istanbul (Turkey); Ceyhan, Tanju; Erbil, Mehmet K. [Department of Biochemistry, Division of Organic Chemistry, Guelhane Medical Academy (GATA), Ankara (Turkey); Ozkaya, Ali Riza [Department of Chemistry, Marmara University, TR34722 Goeztepe, Istanbul (Turkey)], E-mail: aliozkaya@marmara.edu.tr; Bekaroglu, Ozer [Department of Chemistry, Technical University of Istanbul, TR34469 Maslak, Istanbul (Turkey)], E-mail: obek@itu.edu.tr

2007-11-09

In this study, electrochemical, electrochromic and spectroelectrochemical properties of a tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine (Lu{sub 2}Pc{sub 4}2) were investigated explicitly as compared with a tert-butylcalix[4]arene bridged dimeric lutetium(III) phthalocyanine [Lu{sub 2}Pc{sub 2}(OAc){sub 2}1]. Distinctive differences between electrochemical and electrochromic properties of 1 and 2 were detected. Moreover, the properties of 1 and 2 were compared with previously reported S{sub 4}(CH{sub 2}){sub 4} bridged Lu{sub 2}Pc{sub 2}(OAc){sub 2} and Lu{sub 2}Pc{sub 4}. The calixarene bridged phthalocyanine (Pc) compounds, 1 and 2 showed well-defined electrochromic behaviour with green-blue and blue-purple colour transitions. The enhanced electrochromic properties of 2, as compared to 1, were attributed to its double-decker structure, probably allowing the formation of suitable ion channels for the counter ion movement in the solid film.

Time-dependent transcriptional response of GOT1 human small intestine neuroendocrine tumor after 177Lu[Lu]-octreotate therapy.

Science.gov (United States)

Spetz, Johan; Rudqvist, Nils; Langen, Britta; Parris, Toshima Z; Dalmo, Johanna; Schüler, Emil; Wängberg, Bo; Nilsson, Ola; Helou, Khalil; Forssell-Aronsson, Eva

2018-05-01

Patients with neuroendocrine tumors expressing somatostatin receptors are often treated with 177 Lu[Lu]-octreotate. Despite being highly effective in animal models, 177 Lu[Lu]-octreotate-based therapies in the clinical setting can be optimized further. The aims of the study were to identify and elucidate possible optimization venues for 177 Lu[Lu]-octreotate tumor therapy by characterizing transcriptional responses in the GOT1 small intestine neuroendocrine tumor model in nude mice. GOT1-bearing female BALB/c nude mice were intravenously injected with 15 MBq 177 Lu[Lu]-octreotate (non-curative amount) or mock-treated with saline solution. Animals were killed 1, 3, 7 or 41 d after injection. Total RNA was extracted from the tumor samples and profiled using Illumina microarray expression analysis. Differentially expressed genes were identified (treated vs. control) and pathway analysis was performed. Distribution of differentially expressed transcripts indicated a time-dependent treatment response in GOT1 tumors after 177 Lu[Lu]-octreotate administration. Regulation of CDKN1A, BCAT1 and PAM at 1 d after injection was compatible with growth arrest as the initial response to treatment. Upregulation of APOE and BAX at 3 d, and ADORA2A, BNIP3, BNIP3L and HSPB1 at 41 d after injection suggests first activation and then inhibition of the intrinsic apoptotic pathway during tumor regression and regrowth, respectively. Transcriptional analysis showed radiation-induced apoptosis as an early response after 177 Lu[Lu]-octreotate administration, followed by pro-survival transcriptional changes in the tumor during the regrowth phase. Time-dependent changes in cell cycle and apoptosis-related processes suggest different time points after radionuclide therapy when tumor cells may be more susceptible to additional treatment, highlighting the importance of timing when administering multiple therapeutic agents. Copyright © 2018 The Authors. Published by Elsevier Inc. All

Luminescent properties of LuPO4-Pr and LuPO4-Eu nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyi, T.; Vas’kiv, A.; Chylii, M.; Mitina, N.; Zaichenko, A.; Gektin, A.; Voloshinovskii, A.

2016-01-01

Spectral-luminescence parameters of LuPO 4 -Eu and LuPO 4 -Pr nanoparticles of different sizes are studied upon excitation by the synchrotron radiation with photon energies 4–40 eV. Influence of the nanoparticle size on Eu 3+ and Pr 3+ impurity luminescence is analyzed for intracenter and recombination excitation. It is shown that the luminescence intensity of impurities in the case of recombination excitation significantly stronger decreases with decreasing of nanoparticle size compared to intracenter excitation. This feature is explained by the influence of thermalization length to nanoparticle size ratio on the recombination luminescence. Electron recombination luminescence inherent for LuPO 4 -Eu nanoparticles shows a weaker dependence on the nanoparticle size than the hole one in LuPO 4 -Pr nanoparticles. The difference between energy states of praseodymium impurity ions in nanoparticles of different sizes is revealed.

Selective separation of yttrium by CA-100 in the presence of a complexing agent

International Nuclear Information System (INIS)

Sun Xiaobo; Wang Yige; Li Deqian

2006-01-01

The selective separation of Y from yttrium solution containing small heavy rare earth (HRE) impurities (Ho, Er, Tm, Yb, Lu) by liquid-liquid extraction using CA-100 in the presence of a water-soluble complexing agent of ethylenediaminetetraacetic acid (EDTA) was experimentally studied at 298 K. Experiments were carried out in two feeds, Feed-I: [RE] f = 4.94 x 10 -3 M, Y = 98.5%, HRE (Ho, Er, Tm, Yb, Lu) = 1.5%; Feed-II: [RE] f = 4.94 x 10 -3 M, Y = 99.9%, HRE (Ho, Er, Tm, Yb, Lu) = 0.1%, as a function of equilibrium pH (pH eq ), the concentration ratio of [EDTA]:[HRE impurities]. It was shown that the extraction of HRE in the presence of EDTA was suppressed when compared to that of Y because of the masking effect, while the selective extraction of Y was enhanced and the separation factors increased to maximum at appropriate condition for Feed-I: Y/Ho = 1.53, Y/Er 3.09, Y/Tm = 5.61, Y/Yb = 12.04, Y/Lu = 27.51 at pH 4.37 and [EDTA]:[HRE impurities] = 4:1, for Feed-II: Y/Ho = 1.32, Y/Er = 1.91, Y/Tm = 2.00, Y/Yb 3.05, Y/Lu = 3.33 at pH 4.42 and [EDTA]:[HRE impurities] = 8:1. The separation and purification of Y by this method was discussed

Cryogenic Yb: YAG Thin-Disk Laser

Science.gov (United States)

2016-09-09

as a 4- level laser. Its absorption and emission cross-sections increase, and its thermal conductivity improves. Yb:YAG thin disk laser performance...Air Force Base, NM USA 87117 4RINI Technologies, 582 South Econ Circle, Oviedo, FL USA 32765 Keywords: Laser materials; Lasers, ytterbium...temperatures, Yb:YAG behaves as a 4- level laser. Its absorption and emission cross-sections increase, and its thermal conductivity improves. Yb:YAG

Lutetium-177 - Broad Production Capabilities are Expected to Stimulate Clinical Applications of this Important Therapeutic Radioisotope

International Nuclear Information System (INIS)

Knapp, F.F. Jr.

2009-01-01

Lutetium-177 (Lu-177) is of broad interest for therapeutic applications where the deposition of localized radiation can benefit from the limited soft tissue penetration of the 0.497 MeV beta particle (max. = 2.76 mm). Examples of Lu-177 therapeutic strategies include treatment of small SS2/SS5-expressing tumors with targeted peptides and radiosynovectomy. Emission of a 208 keV gamma photon (11 %) allows imaging for evaluation of localization and biokinetics, and for targeting applications, correlation of uptake with therapeutic response. A broad spectrum of research reactors with even modest thermal neutron flux (e.g. > 1 x 10 14 ) can produce carrier-added Lu-177 with sufficient specific activity (SA) > 10 Ci/mg Lu by the 'direct' approach by irradiation of Lu-176. For low SA applications, thermal flux of > 10 13 in low-medium flux reactors provides sufficient SA (> 0.5 mCi Lu-177/mg) for preparation of Lu-EDTMP for synovectomy. Although relative Lu-177m/Lu-177 activity levels from 'direct' production can be very low (> 10 -5 ), the Lu-177m impurity levels can present an issue with radioactive waste storage requirements at some institutions. The alternative 'indirect' approach using decay of reactor produced ytterbium-177 available from by neutron irradiation of enriched Yb-176 targets provides no-carrier-added (nca) Lu-177 (theoretical SA = 109 Ci/mg Lu). Purification of the microscopic levels of nca Lu-177 from macroscopic Yb levels at the high multi Curie production level is a more challenging approach, since production yields are relatively low even at high thermal flux (e.g. 2 x 10 15 neutrons/cm 2 /sec). In addition, high mass Lu/Yb separation is especially time consuming, can generate significant waste, and the relatively expensive Yb-176 target material (> 97%, ∼ $ 20/mg) must be recovered, re-purified and used for subsequent target preparation. However, a number of effective methods for the Lu/Yb separation and Yb recovery have been reported, and even

Dielectric relaxation in Yb-doped SrZrO3

International Nuclear Information System (INIS)

Kamishima, O; Abe, Y; Ishii, T; Kawamura, J; Hattori, T

2004-01-01

The dielectric constant of the proton conductor SrZr 1-x Yb x O 3 (x 0-0.1) was measured as a function of temperature and frequency. Two well-defined relaxation peaks were observed in SrZrO 3 doped with more than 1 mol% of Yb. The assignment of the two dielectric relaxations is discussed in terms of IR spectra and by free energy calculation for a miscibility of dopant Yb ions. The Yb concentration dependence of the relaxation strength of the two dielectric relaxations is in agreement with the results calculated from the free energy. The two relaxations can be assigned to a reorientation of a single Yb-OH dipole and of Yb-OH dipoles associated with Yb-clusters. The attractive energy for Yb-clustering in SrZrO 3 is evaluated at about -85 meV

Collapse of the magnetic moment under pressure of AFe{sub 2} (A=Y, Zr, Lu and Hf) in the cubic Laves phase

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wenxu, E-mail: xwzhang@uestc.edu.cn; Zhang, Wanli

2016-04-15

The electronic structures of four Laves phase iron compounds (e.g. YFe{sub 2}, ZrFe{sub 2}, LuFe{sub 2} and HfFe{sub 2}) have been calculated with a state-of-the-art full potential electronic structure code. Our theoretical work predicted that the magnetic moments collapse under hydrostatic pressure. This feature is found to be universal in these materials. Its electronic origin is provided by the sharp peaks in the density of states near the Fermi level. It is shown that a first order quantum phase transition can be expected under pressure in Y(Zr, or Lu)Fe{sub 2}, while a second order one in HfFe{sub 2}. The bonding characteristics are discussed to elucidate the equilibrium lattice constant variation. The large spontaneous volume magnetostriction gives one of the most important characteristics of these compounds. Invar anomalies in these compounds can be partly explained by the current work when the fast continuous magnetic moment decrease with the decrease of the lattice constant was properly considered. This work may be as a first insight into the rich world of quantum phase transition and Invar mechanism in these Laves phase compounds. - Highlights: • Magnetic moment of YFe{sub 2}, ZrFe{sub 2}, LuFe{sub 2} and HfFe{sub 2} collapses under pressure. • The transition in Y(Zr or Lu) Fe{sub 2} under pressure is first order. • The transition in HfFe{sub 2} under pressure is second order. • The Invar effects in the compounds can be put into the magnetostriction model.

LuFLA1PRO and LuBGAL1PRO promote gene expression in the phloem fibres of flax (Linum usitatissimum).

Science.gov (United States)

Hobson, Neil; Deyholos, Michael K

2013-04-01

Cell type-specific promoters were identified that drive gene expression in an industrially important product. To identify flax (Linum usitatissimum) gene promoters, we analyzed the genomic regions upstream of a fasciclin-like arabinogalactan protein (LuFLA1) and a beta-galactosidase (LuBGAL1). Both of these genes encode transcripts that have been found to be highly enriched in tissues bearing phloem fibres. Using a beta-glucuronidase (GUS) reporter construct, we found that a 908-bp genomic sequence upstream of LuFLA1 (LuFLA1PRO) directed GUS expression with high specificity to phloem fibres undergoing secondary cell wall development. The DNA sequence upstream of LuBGAL1 (LuBGAL1PRO) likewise produced GUS staining in phloem fibres with developing secondary walls, as well as in tissues of developing flowers and seed bolls. These data provide further evidence of a specific role for LuFLA1 in phloem fibre development, and demonstrate the utility of LuFLA1PRO and LuBGAL1PRO as tools for biotechnology and further investigations of phloem fibre development.

New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub 6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd–Yb)

Energy Technology Data Exchange (ETDEWEB)

Pani, M.; Manfrinetti, P.; Provino, A. [INFM and Dipartimento di Chimica e Chimica Industriale, Universita‘ di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1 (Canada); 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.; Garshev, 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); Isnard, O. [Université Grenoble Alpes, Inst NEEL, BP166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 rue des martyrs, F-38042 Grenoble (France)

2014-02-15

Novel RNi{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi{sub 6}Si{sub 6}-type structure for R=Y, Sm, Gd–Yb (tP52, space group P4{sup ¯}b2N 117) that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 5 K. However, the inverse paramagnetic susceptibility of LaNi{sub 6}Si{sub 6} does not follow Curie–Weiss law. The DyNi{sub 6}Si{sub 6} shows ferromagnetic-like saturation behaviour at 5 K in applied fields of 50 kOe, giving rise to a magnetic moment value of 6.5 μ{sub B}/f.u. in 50 kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. - Graphical abstract: Novel (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure and (Y, Sm, Gd–Yb) adopt the new YNi{sub 6}Si{sub 6}-type structure that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 4.2 K. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. Display Omitted - Highlights: • The new (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure. • The new (Y, Sm, Gd–Yb)Ni{sub 6}Si{sub 6} compounds adopt the new YNi{sub 6}Si{sub 6}-type structure. • TbNi{sub 6}Si

Specific heat of the chiral-soliton-lattice phase in Yb(Ni0.94Cu0.06)3Al9

Science.gov (United States)

Ninomiya, Hiroki; Sato, Takaaki; Inoue, Katsuya; Ohara, Shigeo

2018-05-01

We have studied the monoaxial-chiral helimagnet YbNi3Al9 and its-substituted analogue Yb(Ni0.94Cu0.06)3Al9. These compounds belong to a chiral space group R32. In Yb(Ni0.94Cu0.06)3Al9 with the magnetic ordering temperature TM = 6.4 K , only when the magnetic field is applied perpendicular to the helical axis, the chiral soliton lattice is observed below Hc = 10 kOe . YbNi3Al9 with TM = 3.4 K exhibits a metamagnetic transition at Hc = 1 kOe in 2 K. To study the formation of chiral helimagnetic state and chiral soliton lattice, we have measured the specific heat in magnetic fields applied parallel and perpendicular to the helical axis. In zero field, with decreasing temperature, specific heat shows λ-type phase transition from paramagnetic state to chiral helimagnetic one. At the temperature where the chiral soliton lattice emerges, we have found that the specific heat shows a sharp peak. In addition, at around the crossover between paramagnetic state and forced-ferromagnetic one, a broad maximum has been observed. We have determined the magnetic phase diagrams of YbNi3Al9 and Yb(Ni0.94Cu0.06)3Al9.

radiolabeling of DOTA-substance P with 177Lu and biodistribution of 177Lu-DOTA-substance P

International Nuclear Information System (INIS)

Liang Jixin; Li Hongyu; Xiang Xueqin; Luo Zhifu; Luo Hongyi; Hu Liansheng; Chen Yang; Zhuang Ling; Deng Xinrong

2012-01-01

The aim of this project is to evaluate the biodistribution of 177 Lu-DOTA-SP in normal mice and in PANC-1 tumor bearing nude mice and to pave the way for its potentially medical application. In this study, 177 Lu-DOTA-SP was successfully prepared with labeling yield of greater than 90% at optimized conditions and more than 98% of radiochemical purity after C18 Sep-Pak purification. 177 Lu-DOTA-SP showed good stability in saline and in 5% serum while it decomposed slowly in 10% serum. Biodistribution studies in normal mice showed high uptake of 177 Lu-DOTA-SP in the kidneys, indicating the excretion mainly by renal pathway. In addition, 177 Lu-DOTA-SP was washed out from the blood quickly. Bio- distribution of 177 Lu-DOTA-SP in PANC-1 tumor bearing mice showed higher uptake in pancreatic tumor than that in normal pancreas, indicating the presence of NK-1 receptors in PANC-1 pancreatic tumor. However, from SPECT image, no radioactivity accumulation was observed in PANC-1 tumor. Further evaluation is needed to confirm its potential application for radiotherapy of pancreatic cancers. (authors)

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

Science.gov (United States)

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

2014-10-13

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

Neutron-induced cross-sections via the surrogate method

International Nuclear Information System (INIS)

Boutoux, G.

2011-11-01

The surrogate reaction method is an indirect way of determining neutron-induced cross sections through transfer or inelastic scattering reactions. This method presents the advantage that in some cases the target material is stable or less radioactive than the material required for a neutron-induced measurement. The method is based on the hypothesis that the excited nucleus is a compound nucleus whose decay depends essentially on its excitation energy and on the spin and parity state of the populated compound state. Nevertheless, the spin and parity population differences between the compound-nuclei produced in the neutron and transfer-induced reactions may be different. This work reviews the surrogate method and its validity. Neutron-induced fission cross sections obtained with the surrogate method are in general good agreement. However, it is not yet clear to what extent the surrogate method can be applied to infer radiative capture cross sections. We performed an experiment to determine the gamma decay probabilities for 176 Lu and 173 Yb by using the surrogate reactions 174 Yb( 3 He,pγ) 176 Lu * and 174 Yb( 3 He,αγ) 173 Yb * , respectively, and compare them with the well-known corresponding probabilities obtained in the 175 Lu(n,γ) and 172 Yb(n,γ) reactions. This experiment provides answers to understand why, in the case of gamma-decay, the surrogate method gives significant deviations compared to the corresponding neutron-induced reaction. In this work, we have also assessed whether the surrogate method can be applied to extract capture probabilities in the actinide region. Previous experiments on fission have also been reinterpreted. Thus, this work provides new insights into the surrogate method. This work is organised in the following way: in chapter 1, the theoretical aspects related to the surrogate method will be introduced. The validity of the surrogate method will be investigated by means of statistical model calculations. In chapter 2, a review on

Level Densities and Radiative Strength Functions in 170,171Yb

International Nuclear Information System (INIS)

Agvaanluvsan, U.; Schiller, A.; Becker, J.A.; Berstein, L.A.; Guttormsen, M.; Mitchell, G.E.; Rekstad, J.; Siem, S.; Voinov, A.

2003-01-01

Level densities and radiative strength functions in 171 Yb and 170 Yb nuclei have been measured with the 171 Yb( 3 He, 3 He(prime) γ) 171 Yb and 171 Yb( 3 He, αγ) 170 Yb reactions. A simultaneous determination of the nuclear level density and the radiative strength function was made. The present data adds to and is consistent with previous results for several other rare earth nuclei. The method will be briefly reviewed and the result from the analysis will be presented. The radiative strength function for 171 Yb is compared to previously published work.

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.

Data-driven discovery of energy materials: efficient BaM2Si3O10 : Eu2+ (M = Sc, Lu) phosphors for application in solid state white lighting.

Science.gov (United States)

Brgoch, Jakoah; Hasz, Kathryn; Denault, Kristin A; Borg, Christopher K H; Mikhailovsky, Alexander A; Seshadri, Ram

2014-01-01

In developing phosphors for application in solid state lighting, it is advantageous to target structures from databases with highly condensed polyhedral networks that produce rigid host compounds. Rigidity limits channels for non-radiative decay that will decrease the luminescence quantum yield. BaM(2)Si(3)O(10) (M = Sc, Lu) follows this design criterion and is studied here as an efficient Eu(2+)-based phosphor. M = Sc(3+) and Lu(3+) compounds with Eu(2+) substitution were prepared and characterized using synchrotron X-ray powder diffraction and photoluminescence spectroscopy. Substitution with Eu(2+) according to Ba(1-x)Eu(x)Sc(2)Si(3)O(10) and Ba(1-x)Eu(x)Lu(2)Si(3)O(10) results in UV-to-blue and UV-to-blue-green phosphors, respectively. Interestingly, substitution with Eu(2+) in the Lu(3+) containing material produces two emission peaks at low temperature and with 365 nm excitation, as allowed by the two substitution sites. The photoluminescence of the Sc(3+) compound is robust at high temperature, decreasing by only 25% of its room temperature intensity at 503 K, while the Lu-analogue suffers a large drop (75%) from its room temperature intensity. The decrease in emission intensity is explained as stemming from charge transfer quenching due to the short distances separating the luminescent centers on the Lu(3+) substitution site. The correlation between structure and optical response in these two compounds indicates that even though the structures are three-dimensionally connected, high symmetry is required to prevent structural distortions that could impact photoluminescence.

Weak antilocalization effect and noncentrosymmetric superconductivity in a topologically nontrivial semimetal LuPdBi

KAUST Repository

Xu, Guizhou; Wang, Wenhong; Zhang, Xiaoming; Du, Yin; Liu, Enke; Wang, Shouguo; Wu, Guangheng; Liu, Zhongyuan; Zhang, Xixiang

2014-01-01

A large number of half-Heusler compounds have been recently proposed as three-dimensional (3D) topological insulators (TIs) with tunable physical properties. However, no transport measurements associated with the topological surface states have been observed in these half-Heusler candidates due to the dominating contribution from bulk electrical conductance. Here we show that, by reducing the mobility of bulk carriers, a two-dimensional (2D) weak antilocalization (WAL) effect, one of the hallmarks of topological surface states, was experimentally revealed from the tilted magnetic field dependence of magnetoconductance in a topologically nontrivial semimetal LuPdBi. Besides the observation of a 2D WAL effect, a superconducting transition was revealed at T c ∼ 1.7â.K in the same bulk LuPdBi. Quantitative analysis within the framework of a generalized BCS theory leads to the conclusion that the noncentrosymmetric superconductivity of LuPdBi is fully gapped with a possibly unconventional pairing character. The co-existence of superconductivity and the transport signature of topological surface states in the same bulk alloy suggests that LuPdBi represents a very promising candidate as a topological superconductor.

Weak antilocalization effect and noncentrosymmetric superconductivity in a topologically nontrivial semimetal LuPdBi

KAUST Repository

Xu, Guizhou

2014-07-21

A large number of half-Heusler compounds have been recently proposed as three-dimensional (3D) topological insulators (TIs) with tunable physical properties. However, no transport measurements associated with the topological surface states have been observed in these half-Heusler candidates due to the dominating contribution from bulk electrical conductance. Here we show that, by reducing the mobility of bulk carriers, a two-dimensional (2D) weak antilocalization (WAL) effect, one of the hallmarks of topological surface states, was experimentally revealed from the tilted magnetic field dependence of magnetoconductance in a topologically nontrivial semimetal LuPdBi. Besides the observation of a 2D WAL effect, a superconducting transition was revealed at T c ∼ 1.7â.K in the same bulk LuPdBi. Quantitative analysis within the framework of a generalized BCS theory leads to the conclusion that the noncentrosymmetric superconductivity of LuPdBi is fully gapped with a possibly unconventional pairing character. The co-existence of superconductivity and the transport signature of topological surface states in the same bulk alloy suggests that LuPdBi represents a very promising candidate as a topological superconductor.

Study of the viability of the production of lutetium - 177 in the nuclear reactor IEA-R1 at IPEN/CNEN-SP

International Nuclear Information System (INIS)

Silva, Giovana Pasqualini da

2008-01-01

The - emitter 177 Lu is a promising therapeutic radioisotope for the curative treatment of cancer using labelled proteins. It has a half - life of 6.71 day and maximum and average (3 energies of 421 and 133 keV, respectively, resulting in a short range of irradiation of tissue. The decay is accompanied by the emission of low energy -radiation of 208.3 keV (11%) and 113 keV (6.4%), suitable for simultaneous imaging. Lu can be produced by two different routes, namely, by irradiation of natural Lu 2 O 3 target ( 176 Lu, 2.6%) or enriched (in 176 Lu) Lu 2 O 3 target, and also by irradiation of Yb target (Yb 2 O 3 ) followed by radiochemical separation of Lu from Yb isotopes. The objective of this work is the development of a method of the production of 177 Lu through of the (n, gamma) nuclear reaction, by the direct and indirect method of production. Targets of lutetium oxide and ytterbium oxide were irradiated for evaluation of the activity produced and the chemical separation of lutetium and ytterbium was studied using different ion exchange resins. For the direct method, the best results were obtained using the target Lu 2 O 3 enriched in 39.6%. The best results for the indirect method were achieved with the process of separation using 0.25M - HlBA as eluent. The results showed that it is possible to produce 177 Lu of low specific activity for labeling molecules used for bone pain relief and in radiosynoviortesy. (author)

Optical waveguide formed in Yb:GdCOB and Yb:YCOB crystals by 3.0MeV O{sup +} implantation

Energy Technology Data Exchange (ETDEWEB)

Jiao, Yang, E-mail: sdujy@163.com [College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China)

2013-07-15

Planar optical waveguides were formed in Yb:GdCOB and Yb:YCOB crystals by 3.0 MeV O{sup +} ion implantation at fluence of 2 × 10{sup 15} ions/cm{sup 2} at room temperature, respectively. The prism coupling method was performed to characterize the dark-mode property of the waveguides. The refractive index profiles in the waveguides were reconstructed by reflectivity calculation method (RCM). The results show that after the implantation, a 1.5 μm-wide region with enhanced refractive-index was formed beneath the sample surfaces to act as waveguide structures for both Yb:GdCOB and Yb:YCOB.

Improvement in the 111In-DTPA-TYR3-octreotide and 177Lu-DOTATYR3- octreotate production

International Nuclear Information System (INIS)

Souza, Adriano A.; Herrerias, Rosana; Pires, Jose A.; Alves, Geraldo P.; Fukumori, Neuza T.O.; Matsuda, Margareth M.N.; Almeida, Erika V.; Mengatti, Jair; Barboza, Marycel F. de

2009-01-01

Recent advances in receptor mediated-tumor imaging have resulted in the development of somatostatin analogues, the biomolecular basis for the clinical use of these compounds in nuclear medicine for diagnostic and peptide receptor radionuclide therapy (PRRT). PRRT is a very good therapeutic option for patients with metastatic neuroendocrine gastroenteropancreatic (GEP) tumour. Clinical studies with different sst-positives tumors proved advantages of [ 177 Lu-DOTA-Tyr 3 ]octreotate (DOTATATE) for therapy. The aim of this work is to establish and validate the labeling, the quality control procedures of DTPA-Tyr 3 -Octreotide (DTPA-Oct) and DOTA-Tyr 3 -Octreotate (DOTATATE) labeled with In-111 and Lu-177, respectively, for routine production at Radiopharmacy Directory (DIRF) Brazil. Labeling were performed in a 'glove-box' using 111 InCl 3 (Nordion) and in hot-cell with 177 LuCl 3 (IDB-Holland) at pH 4.5; using DTPA-Oct (Pichem) and DOTATATE (IDBHolland) at room temperature and at 82-85 deg C for 30 minutes, respectively. The radiochemical purity was determined by ITLC-SG in 0.1 mol L -1 sodium citrate, pH 5.5 and by Sep-Pak silica cartridge. Sterility was performed by the microbiology procedures and pyrogen tests by the 'in-vitro' Limulus test (LAL). The stability of both radiolabeled peptides was high even 72 hours under refrigeration. The radiochemical purities of the labeled compounds were confirmed by HPLC. Sterility and pyrogen tests were negative in all delivered vials. The efficient procedure to obtain 111 In-DTPA-Oct and 177 Lu-DOTATATE was confirmed in the first comparative clinical groups. The methods were validated and 46.287 GMBq of 111 In-DTPA-Oct and 1,193 GBq of 177 Lu-DOTATATE were distributed in 2008, to nuclear medicine services in Brazil. (author)

Blood clearance and occupational exposure for {sup 177}Lu-DOTATATE compared to {sup 177}Lu-PSMA radionuclide therapy

Energy Technology Data Exchange (ETDEWEB)

Abuqbeitah, Mohammad; Demir, Mustafa; Uslu-Besli, Lebriz; Yeyin, Nami; Soenmezoglu, Kerim [Istanbul University, Department of Nuclear Medicine, Cerrahpasa Faculty of Medicine, Istanbul (Turkey)

2018-03-15

The main target of this work is to examine blood clearance and external exposure for {sup 177}Lu-DOTATATE compared with new emerging {sup 177}Lu-PSMA therapy. Blood clearance and radiation exposure of 31 patients treated with 5.5 ± 1.1 GBq {sup 177}Lu-DOTATATE were compared to those of 23 patients treated with 7.4 GBq {sup 177}Lu-PSMA. Dose rates were measured at several distances and time points up to 120 h after treatment. Blood samples were collected conjunctively after infusion. Caregiver's cumulative dose was measured by means of an OSL (optically stimulated luminescence) dosimeter for 4-5 days and medical staff's dose was also estimated using electronic personal dosimeters. Finger dose was determined via ring TLD (Thermoluminescence Dosimeter) for radiopharmacists and nurses. Dose rates due to {sup 177}Lu-DOTATATE at a distance of 1 m, 4 h and 6 h after infusion, were 3.0 ± 2.8 and 2 ± 1.9 μSv/(h GBq), respectively, while those due to {sup 177}Lu-PSMA were 3.1 ± 0.8 and 2.2 ± 0.9 μSv/(h GBq). Total effective dose of 17 caregivers was 100-200 μSv for {sup 177}Lu-DOTATATE therapy. Mean effective doses to nurses and radiopharmacists were 5 and 4 μSv per patient, respectively, while those for physicists and physicians were 2 μSv per patient. For {sup 177}Lu-DOTATATE, effective half-life in blood and early elimination phase were 0.31 ± 0.13 and 4.5 ± 1 h, while they were found as 0.4 ± 0.1 and 5 ± 1 h, respectively, for {sup 177}Lu-PSMA. The first micturition time following {sup 177}Lu-DOTATATE infusion was noted after 36 ± 14 min, while the second and third voiding times were after 74 ± 9 and 128 ± 41 min, respectively. It is concluded that blood clearance and radiation exposure for {sup 177}Lu-DOTATATE are very similar to those for {sup 177}Lu-PSMA, and both treatment modalities are reasonably reliable for outpatient treatment, since the mean dose rate [2.1 μSv/(h GBq)] decreased below the dose rate that allows release of the patient

A mass spectrometric study of the neutral and ionic vapor components of ytterbium chlorides; formation enthalpies of YbCl2 and YbCl3 molecules, and YbCl3- and YbCl4- ions in the gas phase

International Nuclear Information System (INIS)

Kuznetsov, F.Yh.; Kudin, L.S.; Pogrebnoj, A.M.; Butman, M.F.; Burdukovskaya, G.G.

1997-01-01

Ionic and neutral components of saturated vapour over the ytterbium di-and trichloride is studied through the Knudsen effusive method with mass-spectromic registration of evaporated products within the temperature range of 1000-1300 K. It is found that ytterbium trichloride is subjected to thermal decomposition with formation of ytterbium dichloride and molecular chloride. Sublimation enthalpy and enthalpy of YbCl 2 and YbCl 3 molecules formation in a gaseous phase at 298 K, comprising 356±6, 293±8, -425±6 and -667±6 kJ/mole correspondingly, are determined with application of 2 and 3 thermodynamical laws. Enthalpies of YbCl 3 - and YbCl 4 - negative ions formation in a gaseous phase at 298 K equal to -895 and -1211±30 kJ/mole correspondingly are calculated by measured equilibrium constants ion-molecular reaction. 30 refs., 3 figs., 3 tabs

YB0 SERVICES INSTALLATION COMPLETED

CERN Document Server

The beauty of the completed YB0 was briefly visible at P5 as preparations continue for Tracker installation. A tremendous effort, lasting 7 months and involving more than 100 workers on the busiest days, resulted in 5700 electrical cables, 780 optical cables with 65k fibre channels, and 550 pipes laid on YB0 for HB, EB and Tracker.

Dehybridization of f and d states in the heavy-fermion system YbRh2Si2

Science.gov (United States)

Leuenberger, D.; Sobota, J. A.; Yang, S.-L.; Pfau, H.; Kim, D.-J.; Mo, S.-K.; Fisk, Z.; Kirchmann, P. S.; Shen, Z.-X.

2018-04-01

We report an optically induced reduction of the f -d hybridization in the prototypical heavy-fermion compound YbRh2Si2 . We use femtosecond time- and angle-resolved photoemission spectroscopy to monitor changes of spectral weight and binding energies of the Yb 4 f and Rh 4 d states before the lattice temperature increases after pumping. Overall, the f -d hybridization decreases smoothly with increasing electronic temperature up to ˜250 K but changes slope at ˜100 K . This temperature scale coincides with the onset of coherent Kondo scattering and with thermally populating the first excited crystal electrical field level. Extending previous photoemission studies, we observe a persistent f -d hybridization up to at least ˜250 K , which is far larger than the coherence temperature defined by transport but in agreement with the temperature dependence of the noninteger Yb valence. Our data underlines the distinction of probes accessing spin and charge degrees of freedom in strongly correlated systems.

Complexes of heavy lanthanides with o-aminobenzoic acid

International Nuclear Information System (INIS)

Brzyska, W.; Rzaczynska, Z.

1988-01-01

Anthranilates of Tb-Lu prepared in the reaction of the rare earth hydroxides with ortho-aminobenzoic acid (anthranilic acid) have the general formula Ln(C 6 H 4 NH 2 COO) 3 centredot 2H 2 O where Ln = Tb, Dy, Ho, Er, Tm, Yb, Lu. The water molecules in the hydrated compounds are in the outer coordination sphere. On heating in air at 493 K dehydration occurs and the anhydrous anthranilates Ln(C 6 H 4 NH 2 COO) 3 are formed. On the basis of the IR spectra it was found that the metal in dihydrated anthranilates was simultaneously coordinated through amino and carboxyl groups whereas in anhydrous anthranilates only through the bidentate carboxyl group. From X-ray analysis it was stated that the anthranilates Ln(C 6 H 4 NH 2 COO) 3 centredot 2H 2 O are isostructural, whereas the anhydrous compounds Ln(C 6 H 4 NH 2 COO) 3 are isostructural in the two groups Tb-Er and Tm-Lu. (Author)

Identification and characterization of NF-YB family genes in tung tree.

Science.gov (United States)

Yang, Susu; Wang, Yangdong; Yin, Hengfu; Guo, Haobo; Gao, Ming; Zhu, Huiping; Chen, Yicun

2015-12-01

The NF-YB transcription factor gene family encodes a subunit of the CCAAT box-binding factor (CBF), a highly conserved trimeric activator that strongly binds to the CCAAT box promoter element. Studies on model plants have shown that NF-YB proteins participate in important developmental and physiological processes, but little is known about NF-YB proteins in trees. Here, we identified seven NF-YB transcription factor-encoding genes in Vernicia fordii, an important oilseed tree in China. A phylogenetic analysis separated the genes into two groups; non-LEC1 type (VfNF-YB1, 5, 7, 9, 11, 13) and LEC1-type (VfNF-YB 14). A gene structure analysis showed that VfNF-YB 5 has three introns and the other genes have no introns. The seven VfNF-YB sequences contain highly conserved domains, a disordered region at the N terminus, and two long helix structures at the C terminus. Phylogenetic analyses showed that VfNF-YB family genes are highly homologous to GmNF-YB genes, and many of them are closely related to functionally characterized NF-YBs. In expression analyses of various tissues (root, stem, leaf, and kernel) and the root during pathogen infection, VfNF-YB1, 5, and 11 were dominantly expressed in kernels, and VfNF-YB7 and 9 were expressed only in the root. Different VfNF-YB family genes showed different responses to pathogen infection, suggesting that they play different roles in the pathogen response. Together, these findings represent the first extensive evaluation of the NF-YB family in tung tree and provide a foundation for dissecting the functions of VfNF-YB genes in seed development, stress adaption, fatty acid synthesis, and pathogen response.

One-step synthesis of small-sized and water-soluble NaREF4 upconversion nanoparticles for in vitro cell imaging and drug delivery.

Science.gov (United States)

Yang, Dongmei; Dai, Yunlu; Ma, Pingan; Kang, Xiaojiao; Cheng, Ziyong; Li, Chunxia; Lin, Jun

2013-02-18

Small (2-28 nm) NaREF(4) (rare earth (RE)=Nd-Lu, Y) nanoparticles (NPs) were prepared by an oil/water two-phase approach. Meanwhile, hydrophilic NPs can be obtained through a successful phase-transition process by introducing the amphiphilic surfactant sodium dodecylsulfate (SDS) into the same reaction system. Hollow-structured NaREF(4) (RE=Y, Yb, Lu) NPs can be fabricated in situ by electron-beam lithography on solid NPs. The MTT assay indicates that these hydrophilic NPs with hollow structures exhibit good biocompatibility. The as-prepared hollow-structured NPs can be used as anti-cancer drug carriers for drug storage/release investigations. Doxorubicin hydrochloride (DOX) was taken as model drug. The release of DOX from hollow α-NaLuF(4):20% Yb(3+), 2% Er(3+) exhibits a pH-sensitive release patterns. Confocal microscopy observations indicate that the NPs can be taken up by HeLa cells and show obvious anti-cancer efficacy. Furthermore, α-NaLuF(4):20% Yb(3+), 2% Er(3+) NPs show bright-red emission under IR excitation, making both the excitation and emission light fall within the "optical window" of biological tissues. The application of α-NaLuF(4):20% Yb(3+), 2% Er(3+) in the luminescence imaging of cells was also investigated, which shows a bright-red emission without background noise. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of the viability of the production of lutetium - 177 in the nuclear reactor IEA-R1 at IPEN/CNEN-SP; Estudo da viabilidade de producao do lutecio - 177 no reator nuclear IEA-R1 do IPEN/CNEN-SP

Energy Technology Data Exchange (ETDEWEB)

Silva, Giovana Pasqualini da

2008-07-01

The {sup -} emitter {sup 177} Lu is a promising therapeutic radioisotope for the curative treatment of cancer using labelled proteins. It has a half - life of 6.71 day and maximum and average (3 energies of 421 and 133 keV, respectively, resulting in a short range of irradiation of tissue. The decay is accompanied by the emission of low energy -radiation of 208.3 keV (11%) and 113 keV (6.4%), suitable for simultaneous imaging. Lu can be produced by two different routes, namely, by irradiation of natural Lu{sub 2}O{sub 3} target ({sup 176}Lu, 2.6%) or enriched (in {sup 176}Lu) Lu{sub 2}O{sub 3} target, and also by irradiation of Yb target (Yb{sub 2}O{sub 3}) followed by radiochemical separation of Lu from Yb isotopes. The objective of this work is the development of a method of the production of {sup 177} Lu through of the (n, gamma) nuclear reaction, by the direct and indirect method of production. Targets of lutetium oxide and ytterbium oxide were irradiated for evaluation of the activity produced and the chemical separation of lutetium and ytterbium was studied using different ion exchange resins. For the direct method, the best results were obtained using the target Lu{sub 2}O{sub 3} enriched in 39.6%. The best results for the indirect method were achieved with the process of separation using 0.25M - HlBA as eluent. The results showed that it is possible to produce {sup 177} Lu of low specific activity for labeling molecules used for bone pain relief and in radiosynoviortesy. (author)

Late night activity regarding stroke codes: LuNAR strokes.

Science.gov (United States)

Tafreshi, Gilda; Raman, Rema; Ernstrom, Karin; Rapp, Karen; Meyer, Brett C

2012-08-01

There is diurnal variation for cardiac arrest and sudden cardiac death. Stroke may show a similar pattern. We assessed whether strokes presenting during a particular time of day or night are more likely of vascular etiology. To compare emergency department stroke codes arriving between 22:00 and 8:00 hours (LuNAR strokes) vs. others (n-LuNAR strokes). The purpose was to determine if late night strokes are more likely to be true strokes or warrant acute tissue plasminogen activator evaluations. We reviewed prospectively collected cases in the University of California, San Diego Stroke Team database gathered over a four-year period. Stroke codes at six emergency departments were classified based on arrival time. Those arriving between 22:00 and 8:00 hours were classified as LuNAR stroke codes, the remainder were classified as 'n-LuNAR'. Patients were further classified as intracerebral hemorrhage, acute ischemic stroke not receiving tissue plasminogen activator, acute ischemic stroke receiving tissue plasminogen activator, transient ischemic attack, and nonstroke. Categorical outcomes were compared using Fisher's Exact test. Continuous outcomes were compared using Wilcoxon's Rank-sum test. A total of 1607 patients were included in our study, of which, 299 (19%) were LuNAR code strokes. The overall median NIHSS was five, higher in the LuNAR group (n-LuNAR 5, LuNAR 7; P=0·022). There was no overall differences in patient diagnoses between LuNAR and n-LuNAR strokes (P=0·169) or diagnosis of acute ischemic stroke receiving tissue plasminogen activator (n-LuNAR 191 (14·6%), LuNAR 42 (14·0%); P=0·86). Mean arrival to computed tomography scan time was longer during LuNAR hours (n-LuNAR 54·9±76·3 min, LuNAR 62·5±87·7 min; P=0·027). There was no significant difference in 90-day mortality (n-LuNAR 15·0%, LuNAR 13·2%; P=0·45). Our stroke center experience showed no difference in diagnosis of acute ischemic stroke between day and night stroke codes. This

Development of Yb-169 radiation source for new nondestructive inspection

International Nuclear Information System (INIS)

Yamabayashi, Hisamichi

1994-01-01

As the nondestructive inspection method for large structures, there has been radiography, and X-ray and γ-ray have been used as the radiation. The transmissivity of radiation through materials changes by the energy of the radiation and the density and thickness of the materials. At present about 880 γ-ray radiography apparatuses are used in Japanese private enterprises, and about 70% of them use 192 Ir γ-ray sources, and about 30% use 60 Co or 137 Cs sources. Recently the defect inspection for the worlded parts of thin wall small tubes and so on have become to be regarded as important, and the 169 Yb source that emits lower energy γ-ray is suitable to the purpose. There are many reports that 169 Yb radiography was applied successfully. As the 169 Yb radiation source, pellets and balls are on the market. 169 Yb is made by the neutron irradiation of 168 Yb in nuclear reactors. The characteristics of 169 Yb, the manufacture of 169 Yb radiation sources and the applicability of 169 Yb radiation sources to nondestructive inspection are reported. Also in Japan, many basic experiments on 169 Yb radiation sources have been carried out, and the irradiation apparatuses are small and light, and the control area can be set small. (K.I.)

Laser-diode pumped 40-W Yb:YAG ceramic laser.

Science.gov (United States)

Hao, Qiang; Li, Wenxue; Pan, Haifeng; Zhang, Xiaoyi; Jiang, Benxue; Pan, Yubai; Zeng, Heping

2009-09-28

We demonstrated a high-power continuous-wave (CW) polycrystalline Yb:YAG ceramic laser pumped by fiber-pigtailed laser diode at 968 nm with 400 mum fiber core. The Yb:YAG ceramic laser performance was compared for different Yb(3+) ion concentrations in the ceramics by using a conventional end-pump laser cavity consisting of two flat mirrors with output couplers of different transmissions. A CW laser output of 40 W average power with M(2) factor of 5.8 was obtained with 5 mol% Yb concentration under 120 W incident pump power. This is to the best of our knowledge the highest output power in end-pumped bulk Yb:YAG ceramic laser.

New homo- and heteroleptic derivatives of trivalent ytterbium containing anion-radical 1,4-diazadiene ligands. Synthesis, properties and crystal structure of (C9H7)2Yb[2-MeC6H4NC(Me)C(Me)NC6H4Me-2] and [PhNC(Ph)C(Ph)NPh]3Yb complexes

International Nuclear Information System (INIS)

Gudilenkov, I.D.; Fukin, G.K.; Cherkasov, A.V.; Shavyrin, A.S.; Trifonov, A.A.; Larionova, Yu.E.

2008-01-01

Reaction of ytterbium bisindenyl complex (C 9 H 7 ) 2 Yb II (THF) 2 (1) with 1,4-diazabutadiene 2-MeC 6 H 4 N=C(Me)-C(Me)=NC 6 H 4 Me-2 ( Me DAD) is accompanied by the oxidation of metal atom until trivalent state and results in the formation of paramagnetic compound of metallocenes type (C 9 H 7 ) 2 Yb III ( Me DAD -. ) (3) containing 1,4-diazabutadiene anion-radical. Structure of complex 3 is ascertained by the X-ray structure analysis. Reactions of bisindenyl (1) and bisfluorenyl (C 13 H 9 ) 2 Yb II (THF) 2 (2) derivatives of bivalent ytterbium with 1,4-diazabutadiene PhN=C(Ph)-C(Ph)=NPh ( Ph DAD) (at 1:2 molar ratio of reagents) proceed with the complete break of Yb-C bonds, oxidation of ytterbium atom until trivalent state, and result in the formation of homoligand complex ( Ph DAD -. ) 3 Yb (6) containing three anion-radical 1,4-diazadiene ligands. Complex 6 was also prepared by the exchange reaction of YbCl 3 with Ph DAD -. K + (1:3) in THF. Complex 6 is characterized by the X-ray structure analysis [ru

Adhesive activity of Lu glycoproteins is regulated by interaction with spectrin

Energy Technology Data Exchange (ETDEWEB)

An, Xiuli; Gauthier, Emilie; Zhang, Xihui; Guo, Xinhua; Anstee, David; Mohandas, Narla; Anne Chasis, Joel

2008-03-18

The Lutheran (Lu) and Lu(v13) blood group glycoproteins function as receptors for extracellular matrix laminins. Lu and Lu(v13) are linked to the erythrocyte cytoskeleton through a direct interaction with spectrin. However, neither the molecular basis of the interaction nor its functional consequences have previously been delineated. In the present study, we defined the binding motifs of Lu and Lu(v13) on spectrin and identified a functional role for this interaction. We found that the cytoplasmic domains of both Lu and Lu(v13) bound to repeat 4 of the spectrin chain. The interaction of full-length spectrin dimer to Lu and Lu(v13) was inhibited by repeat 4 of {alpha}-spectrin. Further, resealing of this repeat peptide into erythrocytes led to weakened Lu-cytoskeleton interaction as demonstrated by increased detergent extractability of Lu. Importantly, disruption of the Lu-spectrin linkage was accompanied by enhanced cell adhesion to laminin. We conclude that the interaction of the Lu cytoplasmic tail with the cytoskeleton regulates its adhesive receptor function.

The contribution of valence unstable ytterbium states into kinetic properties of YbNi2-xGe2+x and YbCu2-xSi2+x

International Nuclear Information System (INIS)

Kuzhel, B.C.; Shcherba, I.D.; Kravchenko, I.I.

2006-01-01

The intermetalic YbNi 2-x Ge 2+x (-0.25>=x>=0.25) and YbCu 2-x Si 2+x (-0.20>=x>=0.20) alloy systems (CeGa 2 Al 2 -type crystal structure) were studied by measuring X-ray absorption and diffraction at room temperatures as well as electrical resistivity and thermopower in the 4.2-300K temperature range. The temperature dependence of the contribution of valence unstable Yb ions to the total electrical resistance has been analyzed. The qualitative estimation of this contribution has been performed by utilizing the following equation:Δρ Yb (T)=ρ exp (T)-ρ YbCu 2 Ge 2 (T)-Δρ 4.2K ,where Δρ YbCu 2 Ge 2 (T) is the temperature dependence of YbCu 2 Ge 2 electrical resistance, Δρ 4.2 =ρ 4.2 (exp)-ρ 4.2 (YbCu 2 Ge 2 )

NIR to visible frequency upconversion in Er{sup 3+} and Yb{sup 3+} codoped ZrO{sub 2} phosphor

Energy Technology Data Exchange (ETDEWEB)

Singh, Vijay; Kim, Sang Hwan [Konkuk University, Department of Chemical Engineering, Seoul (Korea, Republic of); Rai, Vineet Kumar [Indian School of Mines, Department of Applied Physics, Dhanbad (India); Al-Shamery, Katharina [University of Oldenburg, Physical Chemistry, Institute for Pure and Applied Chemistry and Center of Interface Science, Oldenburg (Germany); Haase, Markus [University of Osnabrueck, Department of Inorganic Chemistry I-Materials Research, Institute of Chemistry, Osnabrueck (Germany)

2013-11-15

The ZrO{sub 2}:Er{sup 3+} codoped with Yb{sup 3+} phosphor powders have been prepared by the urea combustion route. Formation of the compounds ZrO{sub 2}:Er{sup 3+} and ZrO{sub 2}:Er{sup 3+}, Yb{sup 3+} was confirmed by XRD. The frequency upconversion emissions in the green and red regions upon excitation with a CW diode laser at {proportional_to}978 nm are reported. Codoping with Yb{sup 3+} enhances the emission intensities of the triply ionized erbium in the green and red spectral regions by about {proportional_to}130 and {proportional_to}820 times respectively. The emission properties of the ZrO{sub 2}:Er{sup 3+} phosphor powders are discussed on the basis of excited state absorption, energy transfer, and cross-relaxation energy transfer mechanisms. (orig.)

Comparison of Spectral and Scintillation Properties of LuAP:Ce and LuAP:Ce,Sc Single Crystals

Science.gov (United States)

Petrosyan, Ashot G.; Derdzyan, Marina; Ovanesyan, Karine; Shirinyan, Grigori; Lecoq, Paul; Auffray, Etiennette; Kronberger, Matthias; Frisch, Benjamin; Pedrini, Christian; Dujardin, Christophe

2009-10-01

Scintillation properties of LuAP:Ce and LuAP:Ce,Sc crystal series were studied under excitation by gamma-rays from a 137Cs source. Both series demonstrated comparable optical quality in terms of underlying absorption at 260 nm, slope of the optical edge and transmission in the range of emission. The light yield of LuAP:Ce crystals measured in 0.2 cm times 0.2 cm times 0.8 cm pixels increases linearly with the Ce concentration reaching at 0.58 at. % 6448 plusmn 322 ph/MeV and 9911 plusmn 496 ph/MeV in the long and in the short directions respectively (the light yield ratio is 65%) and shows no sign of light saturation. The energy resolution is found to depend, among other factors, on the uniformity of Ce concentration within the pixels and is improved to 7.1 plusmn 0.4% (I = 0.2 cm), 9.5 plusmn 0.5% (I = 0.8 cm). Intentional co-doping with Sc + ions was tested and resulted in increase of the Ce distribution coefficient to about 0.3. This enabled to increase the concentration of Ce in LuAP:Ce,Sc crystals up to 0.7 at. %, while conserving high optical quality. In contrast to LuAP:Ce, the light yield in LuAP:Ce,Sc crystals does not increase with Ce concentration, the photo peak being gradually suppressed. The involved mechanisms are discussed basing on measurements of the unit cell volumes, Ce concentration uniformity, x-ray rocking spectra, absorption spectra of pure and variously doped LuAP crystals, and emission spectra under different excitations.

High spin K isomeric target of 177mLu

International Nuclear Information System (INIS)

Roig, O.; Belier, G.; Daugas, J.-M.; Delbourgo, P.; Maunoury, L.; Meot, V.; Morichon, E.; Sauvestre, J.-E.; Aupiais, J.; Boulin, Y.; Fioni, G.; Letourneau, A.; Marie, F.; Ridikas, D.

2004-01-01

The techniques used to produce a 177m Lu (J π =23/2 - ,T 1/2 =160.4 days) target are described in this paper. Firstly, an isotopic separation of an enriched lutetium sample was used to reach a purity of 176 Lu close to 99.993%. Afterwards, the high neutron flux of the Grenoble Institut Laue-Langevin reactor was used to produce the 177m Lu isomer by the 176 Lu(n,γ) reaction. Finally, a chemical separation was performed to extract 10 13 nuclei of 177m Lu. Thanks to this experiment, we have been able to estimate the destruction cross-section of the 177m Lu

Magnetocaloric effect in In doped YbMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Sattibabu, Bhumireddi, E-mail: bsb.satti@gmail.com [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Department of Electronics and Physics, Institute of Science, GITAM University, Visakhapatnam 530045 (India); Bhatnagar, A.K., E-mail: anilb42@gmail.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Vinod, K.; Mani, Awadhesh [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2017-06-01

Magnetic and magnetocaloric (MCE) properties of Yb{sub 0.9}In{sub 0.1}MnO{sub 3} and Yb{sub 0.8}In{sub 0.2}MnO{sub 3} polycrystalline samples are presented in this paper. Isothermal magnetization measurements reveal a field induced magnetic transition. Magnetic entropy change of 2.34±0.35 J/mole-K for Yb{sub 0.9}In{sub 0.1}MnO{sub 3} and 2.64±0.38 J/mole-K for Yb{sub 0.8}In{sub 0.2}MnO{sub 3} field change ΔH =10 KOe is observed around the ferromagnetic ordering temperature of Yb{sup 3+}. Values of relative cooling power for the same field change are found to be 38.03±9 J /mol, and 40.90±10 J/mol for Yb{sub 0.9}In{sub 0.1}MnO{sub 3} and Yb{sub 0.8}In{sub 0.2}MnO{sub 3}, respectively. These values suggest In doped YbMnO{sub 3} may be a potential candidate for magnetic refrigerant at low temperatures.

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

Science.gov (United States)

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

2013-03-04

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

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

Laser-cooling effects in few-ion clouds of Yb+

International Nuclear Information System (INIS)

Edwards, C.S.; Gill, P.; Klein, H.A.; Levick, A.P.; Rowley, W.R.C.

1994-01-01

We report some laser-cooling effects in a few 172 Yb + ions held in a Paul trap. Pronounced cloud-to-crystal phase transitions have been observed as discontinuities in the Yb + fluorescence spectrum of the 369 nm cooling transition. The first reported two-dimensional images of Yb + clouds with evidence of crystal structure have been recorded using a photon-counting position-sensitive detector. An ion temperature of 100 mK has been estimated from the size of a single ion image. Stepwise cooling of a re-heated, few-ion Yb + cloud was also observed. (orig.)

New anisotropic rare earth fluorides BaR2F8(R=Y,Dy-Lu): growth and characterization

International Nuclear Information System (INIS)

Kaminskii, A.A.; Butashin, A.V.; Sulyanov, S.N.; Bagayev, S.N.; Eichler, H.J.; Findeisen, J.; Liu, B.; Taeuber, U.; Peuser, P.

1998-01-01

Polymorphism of BaR 2 F 8 compounds is analyzed, and some peculiarities of the crystal growth from the melt are discussed. We report on the orthorhombic BaLu 2 F 8 crystal with ordered structure, a new crystalline material for generating Ln 3+ activator ions. Spectroscopic and laser characteristics of Nd 3+ - and Er 3+ -doped BaLu 2 F 8 samples are discussed as representative examples. Besides, we pay special attention to monoclinic BaY 2 F 8 :Er 3+ crystals, as active media for highly efficient CW 3 μm laser-diode pumped lasers. (orig.)

Radiochemical separations of target-like reaction products from Au-, Pt-, and Th-targets after irradiation with GeV protons

International Nuclear Information System (INIS)

Szweryn, B.; Bruechle, W.; Schausten, B.; Schaedel, M.

1988-08-01

Chemical separation procedures for separations of reaction products after spallation reactions with 2.6 GeV protons and heavy element targets are presented. To determine independent cross sections of individual isotopes the elements Au, Pt, Ir, Os, Re, W, Ta, Hf, (Lu, Yb, Tm, Er), (Gd, Eu, Sm), were separated from gold targets, Pt, Ir, Os, W, Ta, Hf, (Lu, Yb, Tm, Er), (Gd, Eu, Sm) from a platinum target and Au, Tl from a thorium target. (orig.)

Magnetic linear dichroism in x-ray emission spectroscopy: Yb in Yb3 Fe5 O12

NARCIS (Netherlands)

Groot, F.M.F. de; Krisch, M.H.; Sette, F.; Vogel, J.

2000-01-01

A magnetic linear dichroism MLD effect of up to 5% has been observed in the 2p 1/2 4d x-ray emission spectrum of Yb in Yb 3 Fe 5 O 12 . The spectral shape is well reproduced with an atomic multiplet calculation of the 4d to 2p decay. It is shown that the details of the spectral shapes are

New silicates of rare earths and calcium

International Nuclear Information System (INIS)

Andreev, I.F.; Shevyakov, A.M.; Smorodina, T.P.; Semenov, N.E.

1975-01-01

The complex silicates of the third subgroup elements of lanthanides and calcium were synthesized: Ca 3 Er 2 Si 6 O 18 , Ca 3 Lu 2 Si 6 O 18 and Ca 3 Yb 2 Si 6 O 18 . To specify these compounds their physical and chemical properties were studied by means of roentgenographic, IR spectroscopic and crystaloptical methods. The values of Ng, Np,Δn,m,p were determined, the elementary cell parameters: a,b,c,α,β,γ were computed. Existence of such compounds and their analogy in ternary systems MeO-Ln 2 O 3 -SiO 2 were forcasted

Formation of Deep Electron Trap by Yb3+ Codoping Leads into Super-Long Persistent Luminescence in Ce3+-doped Yttrium Aluminum Gallium Garnet Phosphors.

Science.gov (United States)

Ueda, Jumpei; Miyano, Shun; Tanabe, Setsuhisa

2018-05-23

The Y 3 Al 2 Ga 3 O 12 :Ce 3+ -Cr 3+ compound is one of the brightest persistent phosphors, but its persistent luminescence (PersL) duration is not so long due to the relatively shallow Cr 3+ electron trap. Comparing the vacuum referred binding energy of the electron trapping state by Cr 3+ and those by lanthanide ions, we selected Yb 3+ as a deeper electron trapping center. The Y 3 Al 2 Ga 3 O 12 :Ce 3+ -Yb 3+ phosphors show Ce 3+ :5d→4f green persistent luminescence after ceasing blue light excitation. The formation of Yb 2+ was confirmed by the increased intensity of absorption at 585 nm during the charging process. This result indicates that the Yb 3+ ions act as electron traps by capturing an electron. From the thermoluminescence glow curves, it was found the Yb 3+ trap makes much deeper electron trap with 1.01 eV depth than the Cr 3+ electron trap with 0.81 eV depth. This deeper Yb 3+ trap provides much slower detrapping rate of filled electron traps than the Cr 3+ -codoped persistent phosphor. In addition, by preparing transparent ceramics and optimizing Ce 3+ and Yb 3+ concentrations, the Y 3 Al 2 Ga 3 O 12 :Ce 3+ (0.2%)-Yb 3+ (0.1%) as-made transparent ceramic phosphor showed super long persistent luminescence for over 138.8 hours after ceasing blue light charging.

Magnetic order and spin dynamics in the heavy Fermion system YbNi{sub 4}P{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Spehling, Johannes; Guenther, Marco; Yeche, Nicholas; Klauss, Hans-Henning [Institut fuer Festkoerperphysik, TU Dresden (Germany); Luetkens, Hubertus; Baines, Chris [Laboratory for Muonm Spin Spectroscopy, Paul Scherrer Institut, Villigen (Switzerland); Krellner, Cornelius; Geibel, Christoph; Steglich, Frank [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

2012-07-01

A longstanding question in the field of quantum criticality relates to the possible existence of a ferromagnetic (FM) quantum critical point (QCP). At a QCP, collective quantum fluctuations tune the system continuously from a magnetically ordered to a non-magnetic ground state. However, so far no 4f-material with a FM QCP is found. Recently, in the HF metal YbNi{sub 4}P{sub 2} with a quasi 1D-electronic structure, FM quantum criticality above a low FM transition temperature of T{sub C}=170 mK was suggested. Our zero field muon spin relaxation on YbNi{sub 4}P{sub 2} proves static magnetic order with a strongly reduced ordered Yb{sup 3+} moment below T{sub C}. Above T{sub C}, the muon asymmetry function P(t,B) is dominated by quasi homogeneous spin fluctuations and exhibits a time-field scaling relation P(t,B)=P(t/B{sup {gamma}}) indicating cooperative critical spin dynamics. At T=190 mK, slightly above T{sub C}, {gamma}=0.81(5) K suggesting time-scale invariant power-law behavior for the dynamic electronic spin-spin autocorrelation function. The results are discussed in comparison with the AFM compound YbRh{sub 2}Si{sub 2}.

Synthesis, magnetism and electronic structure of YbNi{sub 2-x}Fe{sub x}Al{sub 8} (x=0.91) isolated from Al flux

Energy Technology Data Exchange (ETDEWEB)

Xiuni, Wu [Department of Physical Sciences, Rhode Island College, Providence, RI 02908 (United States); Francisco, Melanie [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Rak, Zsolt [Department of Physics, Michigan State University, East Lansing, MI 48824 (United States); Bakas, T [Department of Physics, University of Ioannina, GR-45110 Ioannina (Greece); Mahanti, S D [Department of Physics, Michigan State University, East Lansing, MI 48824 (United States); Kanatzidis, Mercouri G. [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States)], E-mail: m-kanatzidis@northwestern.edu

2008-12-15

The combination of ytterbium, nickel, iron in liquid aluminum resulted in the formation of the new intermetallic compound YbNi{sub 2-x}Fe{sub x}Al{sub 8} (x=0.91) which adopts the CaCo{sub 2}Al{sub 8} structure type with a=14.458(3) A, b=12.455(3) A, c=3.9818(8) A and space group Pbam. Its resistivity drops with decreasing temperature, saturating to a constant value at lower temperatures. Above 50 K, the inverse magnetic susceptibility data follows Curie-Weiss Law, with a calculated {mu}{sub eff}=2.19 {mu}{sub B}. Although the observed reduced moment in magnetic susceptibility measurement suggests that the Yb ions in this compound are of mixed-valent nature, ab initio electronic structure calculations within density functional theory using LDA+U approximation give an f{sup 13} configuration in the ground state. - Graphical abstract: The reaction of ytterbium, nickel, iron in aluminum flux gives crystals of the intermetallic compound YbNi{sub 2-x}Fe{sub x}Al{sub 8} (x=0.96) which adopts the CaCo{sub 2}Al{sub 8} structure, ab initio electronic structure calculations within density functional theory using LDA+U approximation suggest an f{sup 13} configuration in the ground state.

Surfaces and Interfaces of Magnetoelectric Oxide Systems

Science.gov (United States)

Cao, Shi

Magnetoelectric materials Cr2O3, hexagonal LuFeO 3 and YbFeO3 are studied in this thesis. The surface of chromia (Cr2O3) has a surface electronic structure distinct from the bulk. Our work shows that placing a Cr2O3 single crystal into a single domain state will result in net Cr2O 3 spin polarization at the boundary, even in the presence of a gold overlayer. From the Cr 2p3/2 X-ray magnetic circular dichroism signal, there is clear evidence of interface polarization with overlayers of both Pd and Pt on chromia. Cobalt thin films on Cr2O3(0001) show larger magnetic contrast in magnetic force microscopy indicating enhancement of perpendicular anisotropy induced by Cr2O3. The interfacial charge transfer between mechanically exfoliated few-layer graphene and Cr2O3(0001) surfaces has been investigated showing hole doping of few-layer graphene. Density functional theory calculations furthermore confirm the p-type nature of the graphene on top of chromia, and suggest that the chromia is able to induce a significant carrier spin polarization in the graphene layer. The surface termination and the nominal valence states for hexagonal LuFeO3 thin films were characterized. The stable surface terminates in a Fe-O layer. This is consistent wit the results of density functional calculations. The structural transition at about 1000 °C, from the hexagonal to the orthorhombic phase of LuFeO3, has been investigated in thin films of LuFeO3. The electronic structure for the conduction bands of both hexagonal and orthorhombic LuFeO3 thin films have been measured. Dramatic differences in both the spectral features and the linear dichroism are observed. We have also studied the ferrimagnetism in h-YbFeO3 by measuring the magnetization of Fe and Yb separately. The results directly show antialignment of magnetization of Yb and Fe ions in h-YbFeO3 at low temperature, with an exchange field on Yb of about 17 kOe. All ferrimagnets, by default, are magnetoelectrics. These findings directly

Alternative method to determine Specific Activity of (177)Lu by HPLC.

Science.gov (United States)

Breeman, Wouter A P; de Zanger, Rory M S; Chan, Ho Sze; de Blois, Erik

2015-01-01

Peptide Receptor Radionuclide Therapy (PRRT) with (177)Lu-DOTA-peptides requires (177)Lu with high specific activity (SA) and values >740 GBq (177)Lu per mg Lu to maximise the atom% of (177)Lu over total Lu. Vendors provide SA values which are based on activity and mass of the target, whereas due to "burn-up" of target, these SA values are not accurate. For a radiochemist the SA of (177)Lu is of interest prior to radiolabeling. An alternative method to determine SA was developed by HPLC, which includes a metal titration of a known amount of DOTA-peptide with a known amount of activity ((177)Lu), and a unknown amount of metal ((177+nat)Lu). Based on an HPLC separation of radiometal-DOTA-peptide and DOTA-peptide, and the concordant ratio of these components the metal content ((177+nat)Lu) can be calculated, and eventually the SA of (177)Lu can be accurately determined. These experimentally determined SA values exceeded the estimated values provided by vendors by 27 ± 16%, (range 6-73 %). The deviation of SA values for samples from the same Lu batch was <2% (n ≥ 10). the SA of (177)Lu is apparently often higher as stated by vendors in comparison to the experimentally determined actual values. For this reason, the SA of (177)Lu-DOTA-TATE and other Lu-DOTA-peptides could be increased accordingly.

Convenient Reduction of Carbonyl Compounds to their ...

African Journals Online (AJOL)

NICO

Alcohols and their derivatives occupy an important position in organic synthesis. ... review also reveals that the reduction of carbonyl compounds ..... 1 H.B. Ji and Y.B. She, Green Oxidation and Reduction, China Petrochemi- cal Press, Beijing ...

Post-adsorption process of Yb phosphate nano-particle formation by Saccharomyces cerevisiae

Science.gov (United States)

Jiang, MingYu; Ohnuki, Toshihiko; Tanaka, Kazuya; Kozai, Naofumi; Kamiishi, Eigo; Utsunomiya, Satoshi

2012-09-01

In this study, we have investigated the post-adsorption process of ytterbium (Yb) phosphate nano-particle formation by Saccharomyces cerevisiae (yeast). The yeast grown in P-rich medium were exposed to 1.44 × 10-4 mol/L Yb(III) solution for 2-120 h, and 2 months at 25 ± 1 °C at an initial pH of 3, 4, or 5, respectively. Ytterbium concentrations in solutions decreased as a function of exposure time. Field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FESEM), transmission electron microscopy (TEM), and synchrotron-based extended X-ray absorption fine structure (EXAFS) analyses revealed that nano-sized blocky Yb phosphate with an amorphous phase formed on the yeast cells surfaces in the solutions with Yb. These nano-sized precipitates that formed on the cell surfaces remained stable even after 2 months of exposure at 25 ± 1 °C around neutral pHs. The EXAFS data revealed that the chemical state of the accumulated Yb on the cell surfaces changed from the adsorption on both phosphate and carboxyl sites at 30 min to Yb phosphate precipitates at 5 days, indicating the Yb-phosphate precipitation as a major post-adsorption process. In addition, the precipitation of Yb phosphate occurred on cell surfaces during 7 days of exposure in Yb-free solution after 2 h of exposure (short-term Yb adsorption) in Yb solution. These results suggest that the released P from the inside of yeast cells reacted with adsorbed Yb on cell surfaces, resulting in the formation of Yb precipitates, even though no P was added to the exposure solution. In an abiotic system, the EXAFS data showed that the speciation of sorbed Yb on the reference materials, carboxymethyl cellulose and Ln resin, did not change even when the Yb was exposed to P solution, without forming Yb phosphate precipitates. This result strongly suggests that the cell surface of the yeast plays an important role in the Yb-phosphate precipitation process, not only as a carrier of the

Labelling of ethylenediaminetetramethylene phosphonic acid (EDTMP) with 175Yb

International Nuclear Information System (INIS)

Azmairit Aziz

2009-01-01

Ytterbium-175 ( 175 Yb) is one of radioisotopes that can be used for therapy due to its β-particle emission (T 1/2 = 4.2 d, E β(max) = 480 keV). Beside that, this radioisotope also emits γ-rays of 113 keV (1.9%), 282 keV (3.1%) and 396 keV (6.5%) which are suitable energy for imaging as long as therapeutic applications. EDTMP could be labeled with radionuclide of 175 Yb as an alternative radiopharmaceutical for bone pain palliation due to bone metastases. Labeling of ethylenediaminetetramethylenephosphonic acid with 175 Yb has been studied. Various influential parameters in labeling conditions i.e. the amount of EDTMP ligand, the pH of labeling, incubation time and the amount of 175 Yb solution were studied in order to obtain high labeling efficiency of 175 Yb-EDTMP. The labeling efficiency was obtained by radiochemical purity that was determined by paper chromatography and paper electrophoresis techniques. The optimum labeling condition was obtained at pH 7, 4 mg of EDTMP ligand, 100 µL (105 µg; 0.6 µmol) of 175 Yb solution and 30 minutes incubation time at room temperature. The complex formed was gave maximum labeling efficiency of 98.81 ± 0.15%. Owing to the results, EDTMP ligand can be labeled with 175 Yb radionuclide with labeling efficiency more than 95%. (author)

Hybrid synchronization of hyperchaotic Lu system

Indian Academy of Sciences (India)

In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid ...

Yb(OTf){sub 3}-catalyzed one-pot three component synthesis for tertiary amines

Energy Technology Data Exchange (ETDEWEB)

Lee, Bum Seok; Kim, Ji Hye; Nam, Tae Kyu; Jang, Doo Ok [Dept. of Chemistry, Yonsei University, Wonju (Korea, Republic of)

2015-07-15

Tertiary amine functionality is found in many natural bioactive products such as alkaloids, amino acids, nucleic acids, pharmaceuticals, and agrochemicals. Tertiary amines have also been used as building blocks for nitrogen-containing organic compounds and synthetic polymers. A one-pot method for direct reductive amination of aldehydes has been developed to synthesize tertiary amines using HMDS as a nitrogen source in the presence of Yb(OTf ){sub 3}. With a stoichiometric amount of HMDS, the reaction afforded the desired tertiary amines without competitive reduction of the parent carbonyl compounds. This reaction offers a convenient and efficient protocol for synthesizing aromatic and aliphatic tertiary amines under mild reaction conditions.

Lifetimes of high-spin states in {sup 162}Yb

Energy Technology Data Exchange (ETDEWEB)

Carpenter, M.P.; Janssens, R.V.F.; Henry, R.G. [and others

1995-08-01

A measurement on lifetimes of high-spin states in the yrast and near-yrast rotational bands in {sup 162}Yb was carried out at ATLAS in order to determine the evolution of collectivity as a function of angular momentum using the {sup 126}Te({sup 40}Ar,4n){sup 162}Yb reaction at 170 MeV. Previous lifetime measurements in the {sup 164,166,168}Yb isotopes showed a dramatic decrease in the transition quadrupole moment Q{sub t} with increasing spin. It was suggested that this decrease in Q{sub t} is brought about by the rotationally-induced deoccupation of high-j configurations, mainly i{sub 13/2} neutrons. If this interpretation is correct, the heavier isotopes should have a larger decrease in Q{sub t} than the lighter mass nuclides due to the position of the Fermi surface in the i{sub 13/2} subshell. Indeed, {sup 160}Yb does not show a clear decrease in Q{sub t} at high spin. No high spin lifetime information exists for {sup 162}Yb, thus this experiment fills the gap of measured Q{sub t}`s in the light Yb series. The data is currently being analyzed.

Near-yrast spectroscopy of 164Yb and neighbouring nuclei

International Nuclear Information System (INIS)

Jonsson, S.; Roy, H. and others.

1983-03-01

High-spin states in 164 Yb have been populated in the 152 Sm( 16 0,4n) and 150 Sm( 18 0,4n) reactions. From studies of γ-γ coincidences, γ-ray angular distributions and conversion electron measurements the level scheme has been constructed. The g-band and the S-band have been established to spin and parity 22(sup)+ and 26(sup)+, respectively, and the rotational sequences (π,α)=(-,1) 1 , (-,0) 1 and (-,0) 2 to 23(sup)-, 24(sup)- and 18(sup)-, respectively. The sidebands in 162 , 164 Er and 164 , 166 Yb are discussed. Constructed two-quasineutron configurations and cranked shell model (CSM) calculations are compared with the experimental results in 164 Yb. Residual interactions between quasiparticles in 164 Yb are calculated. Crossing frequencies and the gain in alignment are summarized for the Yb isotopes and the main features are discussed. (author)

İki uçlu bozukluk 1 ve iki uçlu bozukluk 2 depresyon tedavisi arasındaki farklar

OpenAIRE

Sayar, Kemal

2013-01-01

İki uçlu bozukluk 1 ve 2 depresyonları, klinik açıdan farklılıklar gösterebilmektedir. İki uçlu bozukluk 2 ve iki uçlu bozukluk 1 depresyonların tedavisi arasındaki farklar ise tartışmalı bir alandır. Henüz İki uçlu bozukluk 2 depresyon tedavisi konusunda yeterince kanıt birikmemişse de ilk veriler her iki durumun tedavisinde farklar olması gerektiğini düşündürmektedir. Özellikle antidepresan kullanımı konusunda dikkatli olmak gerekmektedir.

Cold shock protein YB-1 is involved in hypoxia-dependent gene transcription

International Nuclear Information System (INIS)

Rauen, Thomas; Frye, Bjoern C.; Wang, Jialin; Raffetseder, Ute; Alidousty, Christina; En-Nia, Abdelaziz; Floege, Jürgen; Mertens, Peter R.

2016-01-01

Hypoxia-dependent gene regulation is largely orchestrated by hypoxia-inducible factors (HIFs), which associate with defined nucleotide sequences of hypoxia-responsive elements (HREs). Comparison of the regulatory HRE within the 3′ enhancer of the human erythropoietin (EPO) gene with known binding motifs for cold shock protein Y-box (YB) protein-1 yielded strong similarities within the Y-box element and 3′ adjacent sequences. DNA binding assays confirmed YB-1 binding to both, single- and double-stranded HRE templates. Under hypoxia, we observed nuclear shuttling of YB-1 and co-immunoprecipitation assays demonstrated that YB-1 and HIF-1α physically interact with each other. Cellular YB-1 depletion using siRNA significantly induced hypoxia-dependent EPO production at both, promoter and mRNA level. Vice versa, overexpressed YB-1 significantly reduced EPO-HRE-dependent gene transcription, whereas this effect was minor under normoxia. HIF-1α overexpression induced hypoxia-dependent gene transcription through the same element and accordingly, co-expression with YB-1 reduced HIF-1α-mediated EPO induction under hypoxic conditions. Taken together, we identified YB-1 as a novel binding factor for HREs that participates in fine-tuning of the hypoxia transcriptome. - Highlights: • Hypoxia drives nuclear translocation of cold shock protein YB-1. • YB-1 physically interacts with hypoxia-inducible factor (HIF)-1α. • YB-1 binds to the hypoxia-responsive element (HRE) within the erythropoietin (EPO) 3′ enhancer. • YB-1 trans-regulates transcription of hypoxia-dependent genes such as EPO and VEGF.

The Bad Berka dose protocol: comparative results of dosimetry in peptide receptor radionuclide therapy using (177)Lu-DOTATATE, (177)Lu-DOTANOC, and (177)Lu-DOTATOC.

Science.gov (United States)

Schuchardt, Christiane; Kulkarni, Harshad R; Prasad, Vikas; Zachert, Carolin; Müller, Dirk; Baum, Richard P

2013-01-01

The objective of this study is to analyze the in vivo behavior of the (177)Lu-labeled peptides DOTATATE, DOTANOC, and DOTATOC used for peptide receptor radionuclide therapy (PRRNT) of neuroendocrine tumors (NETs), by measuring organ and tumor kinetics and by performing dosimetric calculations. Two hundred fifty-three patients (group 1) with metastasized NET who underwent PRRNT were examined. Out of these, 185 patients received (177)Lu-DOTATATE, 9 were treated with (177)Lu-DOTANOC, and 59 with (177)Lu-DOTATOC. Additionally, 25 patients receiving, in consecutive PRRNT cycles, DOTATATE followed by DOTATOC (group 2) and 3 patients receiving DOTATATE and DOTANOC (group 3) were analyzed. Dosimetric calculations (according to MIRD scheme) were performed using OLINDA software. In group 1, DOTATOC exhibited the lowest and DOTANOC the highest uptake and therefore mean absorbed dose in normal organs (whole body, kidney, and spleen). In group 2, there was a significant difference between DOTATATE and DOTATOC concerning kinetics and normal organ doses. (177)Lu-DOTATOC had the lowest uptake/dose delivered to normal organs and highest tumor-to-kidney ratio. There were no significant differences between the three peptides concerning tumor kinetics and mean absorbed tumor dose. The study demonstrates a correlation between high affinity of DOTANOC in vitro and high uptake in normal organs/whole body in vivo, resulting in a higher whole-body dose. DOTATOC exhibited the lowest uptake and dose delivered to normal tissues and the best tumor-to-kidney ratio. Due to large interpatient variability, individual dosimetry should be performed for each therapy cycle.

Experimental half-life determination of 176Lu

International Nuclear Information System (INIS)

Kossert, Karsten; Jörg, Gerhard; Gostomski, Christoph Lierse v.

2013-01-01

The half-life of the naturally occurring long-lived rare earth isotope 176 Lu was determined by a combination of highly sophisticated experimental procedures in order to further improve the reliability and the precision of literature data. The amount of lutetium in the samples was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using a NIST reference standard. The isotopic ratio N( 176 Lu)/N(Lu) in the samples was measured by means of inductively coupled plasma high resolution mass spectrometry (ICP-HRMS). The activity divided by the mass of Lu was determined by applying liquid scintillation (LS) counting. The LS counting efficiency of the beta/gamma emitter 176 Lu was determined with the CIEMAT/NIST efficiency tracing technique with low uncertainty. The influences of colour quenching and background effects are discussed in this paper. The half-life was found to be 3.640(35)×10 10 y. The result is in good agreement with other evaluations and the relative standard uncertainty of 0.95% is among the lowest of previously published data. - Highlights: • The half-life of 176 Lu was determined by ICP-OES, ICP-HRMS and LSC. • The LSC efficiency was determined with the CIEMAT/NIST method. • The half-life was found to be 3.640(35)×10 10 y

Investigations of the trend followed in heat capacity of Re_6UO_1_2 (s) along lanthanide series

International Nuclear Information System (INIS)

Sahu, Manjulata; Saxena, M.K.; Rawat, Deepak; Dash, Smruti

2017-01-01

The compound RE_6UO_1_2 (s) (RE = Ho, Er, Tm, Yb and Lu) was synthesized by complex polymerisation method and characterised using X-ray diffraction (XRD). Heat capacity measurements of RE_6UO_1_2 (s) were performed with heat flux-type differential scanning calorimeter in the temperature range of 300-870 K. The trend in heat capacity along the rare earth series was proposed for RE_6UO_1_2 (s) and thermodynamic functions were generated. (author)

Synthesis and investigation of rare earth tris-acetylacetonates addUcts with acetylaceoneimine

International Nuclear Information System (INIS)

Trembovetskij, G.V.; Smirnov, E.V.; Murav'eva, I.A.; Martynenko, L.I.

1983-01-01

Adducts of tris-acetylacetonates of pare earths With acetylacetonimine of the composition MA 3 x2L (M=La, Pr, Nd, Eu, Gd, Tb) and MA 3 XL (M=Dy, Ho, Er, Tm, Yb, LU) have been synthesized. The compounds prepared are studied using the methods of elemental analysis, IR spectroscopy, PMR spectroscopy, X-ray phase analysis. Volatile tris-acetylacetonates of the yttrium subgroUp rare earths have been prepared by thermal decomposition of MA 3 xL in vacuum

Mälu defragmenteerimine / Ilja Sundelevitsh

Index Scriptorium Estoniae

Sundelevitsh, Ilja

2007-01-01

Viktor Misiano kureeritud projekt "Mälu tagasitulek" Kumu Kunstimuuseumis kuni 29. VII. Dmitri Gutovi projektist, mis koosneb videotest "Sula" ja "Kajakad" ning kolmest maalist, Valentin Arhipovi projektist "Vassili Grigorjevitsh Arhipovi looming aastail 1962-2006", Juri Leidermani heliinstallatsioonist "Isa jutustus", Jevgeni Fiksi projektist, Gljuklja & Tzaplja (Olga Jegorova, Natalja Pershina) installatsioonist "Punased purjed", Igor Shtsherbini tööst "Defragmenteerimine. Stirlitzi mälu" ja Sergei Bratkovi tööst

Ultraviolet and near-infrared luminescence of LaBO3:Ce3+,Yb3+

Science.gov (United States)

Wei, Heng-Wei; Shao, Li-Ming; Jiao, Huan; Jing, Xi-Ping

2018-01-01

Ce3+ or Yb3+ singly doped LaBO3 and Ce3+-Yb3+ co-doped LaBO3 were prepared by conventional solid state reactions at 1100 °C and their photoluminescence (PL) properties were investigated. The emission spectrum of LaBO3:Ce3+,Yb3+ contains both the Ce3+ ultraviolet (UV) emissions (355 nm and 380 nm) and the Yb3+ near infrared (NIR) emission (975 nm) when excited by the UV light at 270 nm. By using the data of the Ce3+ decay curves and the PL intensities of both Ce3+ and Yb3+, the energy transfer efficiency (η) from Ce3+ to Yb3+, the actual energy transfer efficiency (AE) and the quantum efficiency (Q) of the Yb3+ emission were calculated. In the Ce3+-Yb3+ co-doped LaBO3, Ce3+ can transfer its absorbed energy to Yb3+ efficiently (η can be over 60%), and Yb3+ shows the Q value over 50% when it accepts the energy from Ce3+, which results in the low AE value ∼30%. The energy transfer process from Ce3+ to Yb3+ may be understood by the charge transfer mechanism: Ce3+ + Yb3+ ↔ Ce4+ + Yb2+. Particularly the Ce3+-Yb3+ co-doped LaBO3 phosphor gives the emissions mainly in the UV range and the NIR range with a portion of visible emissions in eye-insensitive range. This unique property may be suitable for applications in anti-counterfeiting techniques and public security affairs.

Ternary silicides ScIr{sub 4}Si{sub 2} and RERh{sub 4}Si{sub 2} (RE = Sc, Y, Tb-Lu) and quaternary derivatives RERh{sub 4}Si{sub 2-x}Sn{sub x} (RE = Y, Nd, Sm, Gd-Lu) - structure, chemical bonding, and solid state NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Vosswinkel, Daniel; Benndorf, Christopher; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Sao Paulo Univ., Sao Carlos (Brazil). Inst. of Physics; Matar, Samir F. [Bordeaux Univ., CNRS, ICMCB, UPR 9048, Pessac (France)

2016-11-01

The silicides ScIr{sub 4}Si{sub 2} and RERh{sub 4}Si{sub 2} (RE = Sc, Y, Tb-Lu) and silicide stannides RERh{sub 4}Si{sub 2-x}Sn{sub x}(RE = Y, Nd, Sm, Gd-Lu) were synthesized from the elements by arc-melting and subsequent annealing. The new compounds crystallize with the orthorhombic YRh{sub 4}Ge{sub 2} type structure, space group Pnma. They were characterized by X-ray powder patterns and several structures were refined from single crystal X-ray diffractometer data. The main structural motifs of this series of silicides are tricapped trigonal prisms formed by the transition metal and rare earth atoms. One of the two crystallographically independent silicon sites allows for formation of solid solutions with tin, exemplarily studied for ErRh{sub 4}Si{sub 2-x}Sn{sub x}. Electronic structure calculations reveal strong covalent Rh-Si bonding as the main stability factor. Multinuclear ({sup 29}Si, {sup 45}Sc, and {sup 89}Y) magic-angle spinning (MAS) NMR spectra of the structure representatives with diamagnetic rare-earth elements (Sc, Y, Lu) are found to be consistent with the crystallographic data and specifically confirm the selective substitution of Sn in the Si2 sites in the quaternary compounds YRh{sub 4}SiSn and LuRh{sub 4}SiSn.

First evidence for triaxial superdeformation in sup 1 sup 6 sup 1 Lu and sup 1 sup 6 sup 2 Lu

CERN Document Server

Bringel, P; Domscheit, J; Neusser, A; Schoenwasser, G; Singh, A K; Amro, H; Axiotis, M; Kröll, T; Napoli, D R; Bazzacco, D; Lunardi, S; Ur, C; Bhattacharya, S; Bhowmik, R; Hagemann, G B; Jensen, D R; Pancholi, S C; Petrache, C M

2003-01-01

High-spin states in sup 1 sup 6 sup 1 Lu and sup 1 sup 6 sup 2 Lu have been investigated using the GASP gamma-ray spectrometer array. Excited states in these nuclei have been populated through the sup 1 sup 0 sup 0 Mo( sup 6 sup 5 Cu, xn) reaction at a beam energy of 260 MeV. Four presumably triaxial superdeformed bands, three in sup 1 sup 6 sup 2 Lu and one in sup 1 sup 6 sup 1 Lu, have been observed. This is the first evidence for triaxial superdeformation in the two isotopes. (orig.)

Non-compound nucleus fission in actinide and pre-actinide regions

Indian Academy of Sciences (India)

2015-07-22

Jul 22, 2015 ... In this article, some of our recent results on fission fragment/product angular distributions are discussed in the context of non-compound nucleus fission. Measurement of fission fragment angular distribution in 28Si+176Yb reaction did not show a large contribution from the non-compound nucleus fission.

Crystal growth by Bridgman and Czochralski method of the ferromagnetic quantum critical material YbNi4P2

Science.gov (United States)

Kliemt, K.; Krellner, C.

2016-09-01

The tetragonal YbNi4P2 is one of the rare examples of compounds that allow the investigation of a ferromagnetic quantum critical point. We report in detail on two different methods which have been used to grow YbNi4P2 single crystals from a self-flux. The first, a modified Bridgman method, using a closed crucible system yields needle-shaped single crystals oriented along the [001]-direction. The second method, the Czochralski growth from a levitating melt, yields large single crystals which can be cut in any desired orientation. With this crucible-free method, samples without flux inclusions and a resistivity ratio at 1.8 K of RR1.8K = 17 have been grown.

Assessment of effect of Yb3+ ion pairs on a highly Yb-doped double-clad fibre laser

Science.gov (United States)

Vallés, J. A.; Martín, J. C.; Berdejo, V.; Cases, R.; Álvarez, J. M.; Rebolledo, M. Á.

2018-03-01

Using a previously validated characterization method based on the careful measurement of the characteristic parameters and fluorescence emission spectra of a highly Yb-doped double-clad fibre, we evaluate the contribution of ion pair induced processes to the output power of a double-clad Yb-doped fibre ring laser. This contribution is proved to be insignificant, contrary to analysis by other authors, who overestimate the role of ion pairs.

High spin K isomeric target of {sup 177m}Lu

Energy Technology Data Exchange (ETDEWEB)

Roig, O. E-mail: olivier.roig@cea.fr; Belier, G.; Daugas, J.-M.; Delbourgo, P.; Maunoury, L.; Meot, V.; Morichon, E.; Sauvestre, J.-E.; Aupiais, J.; Boulin, Y.; Fioni, G.; Letourneau, A.; Marie, F.; Ridikas, D

2004-03-21

The techniques used to produce a {sup 177m}Lu (J{sup {pi}}=23/2{sup -},T{sub 1/2}=160.4 days) target are described in this paper. Firstly, an isotopic separation of an enriched lutetium sample was used to reach a purity of {sup 176}Lu close to 99.993%. Afterwards, the high neutron flux of the Grenoble Institut Laue-Langevin reactor was used to produce the {sup 177m}Lu isomer by the {sup 176}Lu(n,{gamma}) reaction. Finally, a chemical separation was performed to extract 10{sup 13} nuclei of {sup 177m}Lu. Thanks to this experiment, we have been able to estimate the destruction cross-section of the {sup 177m}Lu.

Neutron capture reactions on Lu isotopes at DANCE

CERN Document Server

Roig, O

2010-01-01

The DANCE (Detector for Advanced Neutron Capture Experiments) array located at the Los Alamos national laboratory has been used to obtain the neutron capture cross sections for 175Lu and 176Lu with neutron energies from thermal up to 100 keV. Both isotopes are of current interest for the nucleosynthesis s-process in astrophysics and for applications as in reactor physics or in nuclear medicine. Three targets were used to perform these measurements. One was natLu foil and the other two were isotope-enriched targets of 175Lu and 176Lu. The cross sections are obtained for now through a precise neutron flux determination and a normalization at the thermal neutron cross section value. A comparison with the recent experimental data and the evaluated data of ENDF/B-VII.0 will be presented. In addition, resonances parameters and spin assignments for some resonances will be featured.

Emission bands of phosphorus and calculation of band structure of rare earth phosphides

International Nuclear Information System (INIS)

Al'perovich, G.I.; Gusatinskij, A.N.; Geguzin, I.I.; Blokhin, M.A.; Torbov, V.I.; Chukalin, V.I.; AN SSSR, Moscow. Inst. Novykh Khimicheskikh Problem)

1977-01-01

The method of x-ray emission spectroscopy has been used to investigate the electronic structure of monophosphides of rare-earth metals (REM). The fluorescence K bands of phosphorus have been obtained in LaP, PrP, SmP, GdP, TbP, DyP, HoP, ErP, TmP, YbP, and LuP and also the Lsub(2,3) bands of phosphorus in ErP, TmP, YbP, and LuP. Using the Green function technique involving the muffin-tin potential, the energy spectrum for ErP has been calculated in the single-electron approximation. The hystogram of electronic state distribution N(E) is compared with the experimental K and Lsub(2,3) bands of phosphorus in ErP. The agreement between the main details of N(E) and that of x-ray spectra allows to state that the model used provides a good description of the electron density distribution in crystals of REM monophosphides. In accordance with the character of the N(E) distribution the compounds under study are classified as semimetals or semiconductors with a very narrow forbidden band

Influence of Al-atoms on the spin fluctuation scattering in R(Co,Al)2 compounds

International Nuclear Information System (INIS)

Duc, N.H.; Hung, D.T.; Kim-Ngan, N.H.; Sechovsky, V.

1992-01-01

The resistivity and magnetisation have been measured for the R(Co 1-x Al x ) 2 compounds with R=Nd, Gd, Tb, Dy, Ho, Er and Lu. For x=0.2 the resistivity enhancement is observed below T c , however, for the compounds with R=Lu-Tb only. The results are discussed in terms of the spin fluctuation scattering and indicate that the enhancement of the spin fluctuation scattering is strongly related to the lattice parameter. (orig.)

Synthesis, crystal structure, and magnetism of A{sub 2}Co{sub 12}As{sub 7} (A=Ca, Y, Ce–Yb)

Energy Technology Data Exchange (ETDEWEB)

Tan, Xiaoyan [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Ovidiu Garlea, V. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chai, Ping [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Geondzhian, Andrey Y. [National Research Nuclear University “Moscow Engineering Physics Institute”, 115409 Moscow (Russian Federation); Yaroslavtsev, Alexander A. [National Research Nuclear University “Moscow Engineering Physics Institute”, 115409 Moscow (Russian Federation); European XFEL GmbH, 22761 Hamburg (Germany); Xin, Yan [National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States); Menushenkov, Alexey P. [National Research Nuclear University “Moscow Engineering Physics Institute”, 115409 Moscow (Russian Federation); Chernikov, Roman V. [DESY Photon Science, 22603 Hamburg (Germany); Shatruk, Michael, E-mail: shatruk@chem.fsu.edu [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States)

2016-04-15

Ternary intermetallics, A{sub 2}Co{sub 12}As{sub 7} (A=Ca, Y, Ce–Yb), have been synthesized by annealing mixtures of elements in molten Bi at 1223 K. The materials obtained crystallize in the P6{sub 3}/m variant of the Zr{sub 2}Fe{sub 12}P{sub 7} structure type. The unit cell volume shows a monotonic decrease with the increasing atomic number of the rare-earth metal, with the exception of Ce-, Eu-, and Yb-containing compounds. An examination of these outliers with X-ray absorption near edge structures (XANES) spectroscopy revealed mixed valence of Ce, Eu, and Yb, with the average oxidation states of +3.20(1), +2.47(5), and +2.91(1), respectively, at room temperature. Magnetic behavior of A{sub 2}Co{sub 12}As{sub 7} is generally characterized by ferromagnetic ordering of Co 3d moments at 100–140 K, followed by low-temperature ordering of rare-earth 4f moments. The 3d-4f magnetic coupling changes from antiferromagnetic for A=Pr–Sm to ferromagnetic for A=Ce and Eu–Yb. Polarized neutron scattering experiments were performed to support the postulated ferro- and ferrimagnetic ground states for Ce{sub 2}Co{sub 12}As{sub 7} and Nd{sub 2}Co{sub 12}As{sub 7}, respectively. - Graphical abstract: Title arsenides were synthesized by Bi‐flux method. They exhibit mixed valence for A = Ce, Eu, Yb, ferrimagnetism for A = Ca, Y, Pr–Sm, and ferromagnetism for A = Eu–Tm. - Highlights: • A2Co12As7 (A=Ca, Y, Ce–Yb) were synthesized in Bi flux. • Ce, Eu, Yb exhibit mixed valence in the corresponding structures. • The character of 3d‐4f magnetic coupling changes at the half‐filled f shell. • Materials behave as ferrimagnets for A=Ca, Y, Pr–Sm and as ferromagnets for A=Eu–Yb.

Improvement of the thermal and thermo-oxidative stability of high-density polyethylene by free radical trapping of rare earth compound

Energy Technology Data Exchange (ETDEWEB)

Ran, Shiya; Zhao, Li; Han, Ligang [Laboratory of Polymer Materials and Engineering, Ningbo Institute of Technology, ZhejiangUniversity, Ningbo, 315100 (China); MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Institute of Polymer Composites, Zhejiang University, Hangzhou, 310027 (China); Guo, Zhenghong, E-mail: guozhenghong@nit.zju.edu.cn [Laboratory of Polymer Materials and Engineering, Ningbo Institute of Technology, ZhejiangUniversity, Ningbo, 315100 (China); Fang, Zhengping [Laboratory of Polymer Materials and Engineering, Ningbo Institute of Technology, ZhejiangUniversity, Ningbo, 315100 (China); MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Institute of Polymer Composites, Zhejiang University, Hangzhou, 310027 (China)

2015-07-20

Highlights: • Polyethylene filled with ytterbium trifluoromethanesulfonate was prepared. • A low Yb loading improved thermal stability of PE obviously by radical trapping. • Yb(OTf){sub 3} is expected to be an efficient thermal stabilizer for the polymer. - Abstract: A kind of rare earth compound, ytterbium trifluoromethanesulfonate (Yb(OTf){sub 3}), was introduced into high-density polyethylene (HDPE) by melt compounding to investigate the effect of Yb(OTf){sub 3} on the thermal and thermo-oxidative stability of HDPE. The results of thermogravimetric (TG) and differential scanning calorimetry (DSC) showed that the addition of Yb(OTf){sub 3} made the thermal degradation temperatures dramatically increased, the oxidative induction time (OIT) extended, and the enthalpy (ΔH{sub d}) reduced. Very low Yb(OTf){sub 3} loading (0.5 wt%) in HDPE could increase the onset degradation temperature in air from 334 to 407 °C, delay the OIT from 11.0 to 24.3 min, and decrease the ΔH{sub d} from 61.0 to 13.0 J/g remarkably. Electron spin resonance spectra (ESR), thermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TGA-FTIR), rheological investigation and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) indicated that the free radicals-trapping ability of Yb(OTf){sub 3} was responsible for the improved thermal and thermo-oxidative stability.

Laser-cooling effects in few-ion clouds of Yb[sup +

Energy Technology Data Exchange (ETDEWEB)

Edwards, C.S. (National Physical Lab., Teddington (United Kingdom)); Gill, P. (National Physical Lab., Teddington (United Kingdom)); Klein, H.A. (National Physical Lab., Teddington (United Kingdom)); Levick, A.P. (National Physical Lab., Teddington (United Kingdom)); Rowley, W.R.C. (National Physical Lab., Teddington (United Kingdom))

1994-08-01

We report some laser-cooling effects in a few [sup 172]Yb[sup +] ions held in a Paul trap. Pronounced cloud-to-crystal phase transitions have been observed as discontinuities in the Yb[sup +] fluorescence spectrum of the 369 nm cooling transition. The first reported two-dimensional images of Yb[sup +] clouds with evidence of crystal structure have been recorded using a photon-counting position-sensitive detector. An ion temperature of 100 mK has been estimated from the size of a single ion image. Stepwise cooling of a re-heated, few-ion Yb[sup +] cloud was also observed. (orig.)

YB-1 promotes microtubule assembly in vitro through interaction with tubulin and microtubules

Directory of Open Access Journals (Sweden)

Baconnais Sonia

2008-09-01

Full Text Available Abstract Background YB-1 is a major regulator of gene expression in eukaryotic cells. In addition to its role in transcription, YB-1 plays a key role in translation and stabilization of mRNAs. Results We show here that YB-1 interacts with tubulin and microtubules and stimulates microtubule assembly in vitro. High resolution imaging via electron and atomic force microscopy revealed that microtubules assembled in the presence of YB-1 exhibited a normal single wall ultrastructure and indicated that YB-1 most probably coats the outer microtubule wall. Furthermore, we found that YB-1 also promotes the assembly of MAPs-tubulin and subtilisin-treated tubulin. Finally, we demonstrated that tubulin interferes with RNA:YB-1 complexes. Conclusion These results suggest that YB-1 may regulate microtubule assembly in vivo and that its interaction with tubulin may contribute to the control of mRNA translation.

A broadening temperature sensitivity range with a core-shell YbEr@YbNd double ratiometric optical nanothermometer

Science.gov (United States)

Marciniak, L.; Prorok, K.; Francés-Soriano, L.; Pérez-Prieto, J.; Bednarkiewicz, A.

2016-02-01

The chemical architecture of lanthanide doped core-shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ~980 to the more relevant ~808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb-Er co-doped core nanoparticles with the Yb-Nd co-doped shell, we have intentionally combined temperature dependent Er up-conversion together with temperature dependent Nd --> Yb energy transfer, and thus have expanded the temperature response range ΔT of a single nanoparticle based optical nano-thermometer under single ~808 nm wavelength photo-excitation from around ΔT = 150 K to over ΔT = 300 K (150-450 K). Such engineered nanocrystals are suitable for remote optical temperature measurements in technology and biotechnology at the sub-micron scale.The chemical architecture of lanthanide doped core-shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ~980 to the more relevant ~808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb-Er co-doped core nanoparticles with the Yb-Nd co-doped shell, we have intentionally combined temperature dependent Er up-conversion together with temperature dependent Nd --> Yb energy transfer, and thus have expanded the temperature response range ΔT of a single nanoparticle

Comparison of tumour and whole body absorbed doses of 177-Lu-DOTA-TATE and Lu-177-DOTA-NOC treatment in the same patient group

International Nuclear Information System (INIS)

Yeyin, N.; Kabasakal, L.; Akyel, R.; Demir, M.; Kanmaz, B.; Ocak, M.; Toklu, T.; Selcuk, N.

2015-01-01

Full text of publication follows. Peptide Receptor Radionuclide Therapy (PRRT) with Lu-177 labelled peptides in patients with neuroendocrine tumours (NETs) aroused great interest. An estimation of actual radiation doses to tumours is very important for therapy planning. There are several radiolabelled peptides, which can be used for PRRT with different biological behaviour. Aim: the aim of the study was to compare the tumour and normal organ absorbed doses in patients who have received Lu-177-DOTA-TATE and Lu-177 DOTA-NOC. Materials and methods: study was composed of 20 patients (M/F: 10/10, mean age: 51.5 ± 14.9) with histologically proven inoperable NETs. All patients received Lu-177-DOTA-NOC treatment 6 to 12 weeks after last Lu-177-DOTA-TATE treatment. Dosimetric calculations were performed using MIRD scheme and lesion doses were calculated using post therapy whole body images obtained at 4, 20, 44, and 68 hours after injection. Tumour volumes were determined from CT images. Thirteen blood samples beginning from time zero to 4 days after injection were obtained for bone marrow and whole body dosimetry. Results: There were 53 lesions in Lu-177-DOTA-TATE post-therapy whole body images and 49 lesions in Lu-177 DOTA-NOC post therapy images. Lesions were selected according to lesion delineation and superimposed lesions were excluded. Mean lesion absorbed dose is calculated to be 47.4 ± 53.4 and 42.9 ± 52.8 Gy per 370 MBq for Lu-177-DOTA-TATE and DOTA-NOC respectively (p>0.5). There were significantly higher absorbed doses for kidney and bone marrow after Lu-177-DOTA-NOC treatment as compared to Lu-177-DOTA-TATE treatment, which were 6.9 ± 2.7 vs 3.9 ± 1.7 (p<0.05) and 0.12 ± 0.0 vs 0.10 ± 0.0 (p<0.05) Gy, respectively. There was not any difference in plasma elimination times between two tracers. On the other hand the whole body absorbed dose was significantly higher after Lu-177-DOTA-NOC treatment, which was 0.24 ± 0.07 vs 0.20 ± 0.06 Gy (p<0

Advances on LuGre friction model

OpenAIRE

Fuad, Mohammad; Ikhouane, Fayçal

2013-01-01

LuGre friction model is an ordinary differential equation that is widely used in describing the friction phenomenon for mechanical systems. The importance of this model comes from the fact that it captures most of the friction behavior that has been observed including hysteresis. In this paper, we study some aspects related to the hysteresis behavior induced by the LuGre friction model.

Synthesis, properties, and crystal structure of complex Cp2Yb(DAD)

International Nuclear Information System (INIS)

Trifonov, A.A.; Kirillov, E.N.; Bochkarev, M.N.; Shumani, G.; Myule, S.

1999-01-01

Diazadiene complex of trivalent ytterbium Cp 2 Yb(DAD) (1) (DAD = Bu 1 -N CH-CH = N-Bu 1 ) was obtained by three routes: the oxidation of Cp 2 Yb(THF) 2 by diazadiene in tetrahydrofuran (THF), the reaction of Cp 2 YbCl with DAD 2- Na 2 + (2:1), and the reaction of Cp 2 YbCl(THF) with DAD - K + in the 1:1 ratio. Complex 1 was characterized by microanalysis, IR spectroscopy, magnetochemistry, and X-ray structural analysis [ru

Linear thermal expansivity and Cp measurements for LuHx and LuDx (x=0.005 and 0.053) single crystals

International Nuclear Information System (INIS)

Swenson, C.A.

1996-01-01

Linear thermal expansivity (α) measurements from 1 to 300 K and heat capacity (C p ) measurements from 1 to 110 K are reported for single crystals of the α-Lu hexagonal alloys LuH x and LuD x (x=0.005 and 0.053). The C p data confirm and extend to 110 K earlier 1 to 20 K measurements on LuH x alloys, and show that isotope effects, if any, are small. The small x dependences of the C p close-quote s above 8 K can be associated with small increases in the Debye temperature Θ 0 . This latter interpretation, which is consistent with ultrasonic and other results for these alloys, is valid only if C p is expressed as mJ/gmolK (essentially, per mole of Lu ions). Results are in agreement with the previous conclusion from more extensive polycrystalline LuH x data that the shape of the low-temperature C p vs T relation for x≤0.015 is qualitatively different from that for x≥0.032. The linear thermal expansivities of the c-axis alloys, even for x=0.005, are significantly smaller (by from 3% to 20%) than those for the pure crystals, with large isotope effects and a large, nonlinear x dependence for the low-temperature expansivity data. Other types of data have shown a feature near 170 K which is associated with the completion of pairing of the hydrogens along the c axis in next-nearest-neighbor tetrahedral sites. A distinct (approximately 15 K wide) change in α which is observed near this temperature for each alloy, except for a-axis LuD 0.005 , provides the most direct evidence of such a transition. The temperature of the c-axis discontinuity is slightly isotope and x dependent, and scales approximately with x [+24% on warming for LuH(or D) 0.053 ]. (Abstract Truncated)

Growth and continuous-wave laser operation of disordered crystals of Yb3+:NaLa(WO4)2 and Yb3+:NaLa(MoO4)2

Science.gov (United States)

Liu, J.; Cano-Torres, J. M.; Cascales, C.; Esteban-Betegón, F.; Serrano, M. D.; Volkov, V.; Zaldo, C.; Rico, M.; Griebner, U.; Petrov, V.

2005-03-01

Single crystals of disordered NaLa(WO4)2 and NaLa(MoO4)2 doped with Yb3+ are grown by the Czochralski method from the melt. Continuous-wave laser operation with Ti:sapphire laser pumping is demonstrated at room temperature without special cooling. Tunability from 1017 to 1057 nm and from 1015 to 1053 nm is achieved for Yb:NaLa(WO4)2 and Yb:NaLa(MoO4)2, respectively. A maximum output power of 205 mW is obtained with Yb:NaLa(WO4)2.

YB-1 overexpression promotes a TGF-β1-induced epithelial–mesenchymal transition via Akt activation

International Nuclear Information System (INIS)

Ha, Bin; Lee, Eun Byul; Cui, Jun; Kim, Yosup; Jang, Ho Hee

2015-01-01

The Y-box binding protein-1 (YB-1) is a transcription/translation regulatory protein, and the expression thereof is associated with cancer aggressiveness. In the present study, we explored the regulatory effects of YB-1 during the transforming growth factor-β1 (TGF-β1)-induced epithelial-to-mesenchymal transition (EMT) in lung adenocarcinoma cells. Downregulation of YB-1 increased E-cadherin promoter activity, and upregulation of YB-1 decreased promoter activity, suggesting that the YB-1 level may be correlated with the EMT. TGF-β1 induced YB-1 expression, and TGF-β1 translocated cytosolic YB-1 into the nucleus. YB-1 overexpression promoted TGF-β1-induced downregulation of epithelial markers, upregulation of mesenchymal markers, and cell migration. Moreover, YB-1 overexpression enhanced the expression of E-cadherin transcriptional repressors via TGF-β1-induced Akt activation. Our findings afford new insights into the role played by YB-1 in the TGF-β1 signaling pathway. - Highlights: • YB-1 regulates E-cadherin expression in A549 cells. • TGF-β1 induces upregulating and nuclear localization of YB-1. • YB-1 overexpression accelerates TGF-β1-induced EMT and cell migration. • YB-1 regulates Snail and Slug expression via Akt activation

Sol-Gel Derived Active Material for Yb Thin-Disk Lasers.

Science.gov (United States)

Almeida, Rui M; Ribeiro, Tiago; Santos, Luís F

2017-09-02

A ytterbium doped active material for thin-disk laser was developed based on aluminosilicate and phosphosilicate glass matrices containing up to 30 mol% YbO 1.5 . Thick films and bulk samples were prepared by sol-gel processing. The structural nature of the base material was assessed by X-ray diffraction and Raman spectroscopy and the film morphology was evidenced by scanning electron microscopy. The photoluminescence (PL) properties of different compositions, including emission spectra and lifetimes, were also studied. Er 3+ was used as an internal reference to compare the intensities of the Yb 3+ PL peaks at ~ 1020 nm. The Yb 3+ PL lifetimes were found to vary between 1.0 and 0.5 ms when the Yb concentration increased from 3 to 30 mol%. Based on a figure of merit, the best active material selected was the aluminosilicate glass composition 71 SiO₂-14 AlO 1.5 -15 YbO 1.5 (in mol%). An active disk, ~ 36 μm thick, consisting of a Bragg mirror, an aluminosilicate layer doped with 15 mol% Yb and an anti-reflective coating, was fabricated.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Production of 177Lu for targeted radionuclide therapy: Available options

International Nuclear Information System (INIS)

Dah, Ashutosh; Pillai, Maroor Raghavan Ambikalmajan; Knapp, Furn F. Jr.

2015-01-01

This review provides a comprehensive summary of the production of 177 Lu to meet expected future research and clinical demands. Availability of options represents the cornerstone for sustainable growth for the routine production of adequate activity levels of 177 Lu having the required quality for preparation of a variety of 177 Lu-labeled radiopharmaceuticals. The tremendous prospects associated with production of 177 Lu for use in targeted radionuclide therapy (TRT) dictate that a holistic consideration should evaluate all governing factors that determine its success. While both “direct” and “indirect” reactor production routes offer the possibility for sustainable 177 Lu availability, there are several issues and challenges that must be considered to realize the full potential of these production strategies. This article presents a mini review on the latest developments, current status, key challenges and possibilities for the near future. A broad understanding and discussion of the issues associated with 177 Lu production and processing approaches would not only ensure sustained growth and future expansion for the availability and use of 177 Lu-labeled radiopharmaceuticals, but also help future developments

Dosimetric Studies in Normal Mice of 177Lu-DOTA-SP and 177Lu-DOTA-His2-MG

International Nuclear Information System (INIS)

Puerta Yepes, N.; Rojo, A.M.; Lopez Bularte, A.C.; Nevares, N.; Zapata, M.; Perez, J.H.; Crudo, J.

2010-01-01

DOTA-Substance-P (SP) and DOTA-minigastrin (His2-MG) labeled with 177 Lu could be used in peptide receptor radionuclide therapy (PRRT) for treatment of various tumour species. Biodistribution studies of both radiopharmaceuticals in normal mice were performed at different times. Absorbed doses in mouse organs were estimated and extrapolated to humans. Dosimetric calculations showed that kidneys received the highest dose, for both radiopharmaceuticals. The Maximum Tolerated Activity (MTA) of 177 Lu-DOTA-SP that can be administered without kidney toxicity are 414 and 422 MBq/kg for the standard adult man and woman, respectively. In the same way, the MTA of 177 Lu-DOTA-His2-MG are 488 and 518 MBq/kg for the standard adult man and woman, respectively. (authors)

Mass fabrication of homogeneously Yb-doped silica nanoparticles and their spectroscopic properties

International Nuclear Information System (INIS)

Xiong Liangming; Sekiya, Edson H; Saito, Kazuya

2009-01-01

A large number of homogeneously Yb-doped silica nanoparticles were continually fabricated in a vapor synthesis route, in which the Yb doping level can be well controlled by varying either the heating temperature or the carrier gas flow rate of the Yb precursor. The sizes, shapes, and morphologies of the nanoparticles were examined, and no crystallites and no Yb 2 O 3 clusters were observed in the nanoparticles. These nanoparticles exhibit a clear Yb 3+ -derived absorption at around 973-975 nm and a dependence of the emission intensity and decay time on the doping level, much different from that of sintered pellets.

The contribution of valence unstable ytterbium states into kinetic properties of YbNi{sub 2-x}Ge{sub 2+x} and YbCu{sub 2-x}Si{sub 2+x}

Energy Technology Data Exchange (ETDEWEB)

Kuzhel, B.C. [Department of Physics, Ivan Franko National University of Lviv, 50 Dragomanow Str., 79005, Lviv (Ukraine)]. E-mail: kuzhelb@org.lviv.net; Shcherba, I.D. [Department of Physics, Ivan Franko National University of Lviv, 50 Dragomanow Str., 79005, Lviv (Ukraine); Institute of Techniques, Academy of Pedagogy, Podchorozych 2, 30-084, Krakow (Poland); Kravchenko, I.I. [Department of Physics, University of Florida, P.O. Box 118440, Gainesville, FL 32611 (United States)]. E-mail: kravch@phys.ufl.edu

2006-11-30

The intermetalic YbNi{sub 2-x}Ge{sub 2+x} (-0.25>=x>=0.25) and YbCu{sub 2-x}Si{sub 2+x} (-0.20>=x>=0.20) alloy systems (CeGa{sub 2}Al{sub 2} -type crystal structure) were studied by measuring X-ray absorption and diffraction at room temperatures as well as electrical resistivity and thermopower in the 4.2-300K temperature range. The temperature dependence of the contribution of valence unstable Yb ions to the total electrical resistance has been analyzed. The qualitative estimation of this contribution has been performed by utilizing the following equation:{delta}{rho}{sub Yb}(T)={rho}{sub exp}(T)-{rho}{sub YbCu{sub 2}Ge{sub 2}}(T)-{delta}{rho}{sub 4.2K},where {delta}{rho}{sub YbCu{sub 2}Ge{sub 2}}(T) is the temperature dependence of YbCu{sub 2}Ge{sub 2} electrical resistance, {delta}{rho}{sub 4.2}={rho}{sub 4.2}(exp)-{rho}{sub 4.2}(YbCu{sub 2}Ge{sub 2})

Melt processing of Yb-123 tapes

International Nuclear Information System (INIS)

Athur, S. P.; Balachandran, U.; Salama, K.

2000-01-01

The innovation of a simple, scalable process for manufacturing long-length conductors of HTS is essential to potential commercial applications such as power cables, magnets, and transformers. In this paper the authors demonstrate that melt processing of Yb-123 tapes made by the PIT route is an alternative to the coated conductor and Bi-2223 PIT tape fabrication techniques. Ag-clad Yb-123 tapes were fabricated by groove rolling and subsequently, melt processed in different oxygen partial pressures in a zone-melting furnace with a gradient of 140 C/cm. The transition temperatures measured were found to be around 81 K undermost processing conditions. EPMA of the tapes processed under different conditions show the 123 phase to be Ba deficient and Cu and Yb rich. Critical current was measured at various temperatures from 77 K to 4.2 K. The J c increased with decrease in pO 2 . The highest I c obtained was 52 A at 4.2 K

Comparing Zeeman qubits to hyperfine qubits in the context of the surface code: +174Yb and +171Yb

Science.gov (United States)

Brown, Natalie C.; Brown, Kenneth R.

2018-05-01

Many systems used for quantum computing possess additional states beyond those defining the qubit. Leakage out of the qubit subspace must be considered when designing quantum error correction codes. Here we consider trapped ion qubits manipulated by Raman transitions. Zeeman qubits do not suffer from leakage errors but are sensitive to magnetic fields to first order. Hyperfine qubits can be encoded in clock states that are insensitive to magnetic fields to first order, but spontaneous scattering during the Raman transition can lead to leakage. Here we compare a Zeeman qubit (+174Yb) to a hyperfine qubit (+171Yb) in the context of the surface code. We find that the number of physical qubits required to reach a specific logical qubit error can be reduced by using +174Yb if the magnetic field can be stabilized with fluctuations smaller than 10 μ G .

Comparative study of optical and scintillation properties of YVO4, (Lu0.5Y0.5)VO4, and LuVO4 single crystals

International Nuclear Information System (INIS)

Fujimoto, Yutaka; Yanagida, Takayuki; Yokota, Yuui; Chani, Valery; Kochurikhin, Vladimir V.; Yoshikawa, Akira

2011-01-01

Optical and scintillation properties of YVO 4 , (Lu 0.5 Y 0.5 )VO 4 , and LuVO 4 single crystals grown by the Czochralski (CZ) method with RF heating system are compared. All vanadate crystals show high transmittance (∼80%) in the 400-900 nm wavelength range. In both photo- and radio-luminescence spectra, intense peak around 400-500 nm, which was ascribed to the transition from triplet state of VO 4 3- , was clearly observed. The main decay time component was about 38 μs (YVO 4 ), 18 μs ((Lu 0.5 Y 0.5 )VO 4 ), and 17 μs (LuVO 4 ) under 340 nm excitation. The scintillation light yields of YVO 4 , (Lu 0.5 Y 0.5 )VO 4 , and LuVO 4 crystals (obtained from the 137 Cs excited pulse height spectra) were evaluated to be about 11,200, 10,700, and 10,300 ph/MeV, respectively.

Exploiting fine-grain parallelism in recursive LU factorization

KAUST Repository

Dongarra, Jack

2012-01-01

The LU factorization is an important numerical algorithm for solving system of linear equations. This paper proposes a novel approach for computing the LU factorization in parallel on multicore architectures. It improves the overall performance and also achieves the numerical quality of the standard LU factorization with partial pivoting. While the update of the trailing submatrix is computationally intensive and highly parallel, the inherently problematic portion of the LU factorization is the panel factorization due to its memory-bound characteristic and the atomicity of selecting the appropriate pivots. We remedy this in our new approach to LU factorization of (narrow and tall) panel submatrices. We use a parallel fine-grained recursive formulation of the factorization. It is based on conflict-free partitioning of the data and lock-less synchronization mechanisms. Our implementation lets the overall computation naturally flow with limited contention. Our recursive panel factorization provides the necessary performance increase for the inherently problematic portion of the LU factorization of square matrices. A large panel width results in larger Amdahl\\'s fraction as our experiments have revealed which is consistent with related efforts. The performance results of our implementation reveal superlinear speedup and far exceed what can be achieved with equivalent MKL and/or LAPACK routines. © 2012 The authors and IOS Press. All rights reserved.

Additional lesions detected in therapeutic scans with 177Lu-DOTATATE reflect higher affinity of 177Lu-DOTATATE for somatostatin receptors.

Science.gov (United States)

Mirzaei, Siroos; Bastati, Brigitte; Lipp, Rainer W; Knoll, Peter; Zojer, Niklas; Ludwig, Heinz

2011-01-01

Peptide receptor-targeted radionuclide therapy (PRRT) of somatostatin receptor (SR)-expressing neuroendocrine tumors (NETs) has become an established therapeutic option in patients with advanced NETs. The aim of this study was to compare the lesion detection rate of (99m)Tc-EDDA/HYNIC-TOC, a newly developed tracer for NET imaging, with (177)Lu-DOTATATE used for PRRT. 8 patients (4 women, 4 men, age range 46-76 years) with histologically proven NETs, who showed high SR loads by (99m)Tc-EDDA/HYNIC-TOC scintigraphy, were treated with (177)Lu-DOTATATE. After treatment, all patients were subjected to whole-body scintigraphy with additional low-dose single-photon emission computed tomography (SPECT-CT) of the chest and abdomen. All patients demonstrated (177)Lu-DOTATATE accumulation in all lesions previously detected by (99m)Tc- EDDA/HYNIC-TOC scintigraphy. Three patients showed additional lesions in the liver and lungs. SPECT-CT after (177)Lu-DOTATATE therapy may be helpful in detecting additional lesions not seen using (99m)Tc-EDDA/HYNIC-TOC. This could reflect the broader affinity of (177)Lu-DOTATATE for SRs compared with (99m)Tc-EDDA/HYNIC-TOC. Copyright © 2011 S. Karger AG, Basel.

Electrical resistivity, susceptibility and heat capacity of cubic Kondo compound YbCu.sub.5./sub. prepared by melt-spinning technique

Czech Academy of Sciences Publication Activity Database

Reiffers, M.; Idzikowski, B.; Šebek, Josef; Šantavá, Eva; Ilkovič, S.; Pristáš, G.

378-380, - (2006), s. 738-739 ISSN 0921-4526 Institutional research plan: CEZ:AV0Z10100520 Keywords : YbCu 5 * susceptibility * electrical resistivity * melt spinning Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.872, year: 2006

Fiber-optic thermometer application of thermal radiation from rare-earth end-doped SiO2 fiber

International Nuclear Information System (INIS)

Katsumata, Toru; Morita, Kentaro; Komuro, Shuji; Aizawa, Hiroaki

2014-01-01

Visible light thermal radiation from SiO 2 glass doped with Y, La, Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu were studied for the fiber-optic thermometer application based on the temperature dependence of thermal radiation. Thermal radiations according to Planck's law of radiation are observed from the SiO 2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu at the temperature above 1100 K. Thermal radiations due to f-f transitions of rare-earth ions are observed from the SiO 2 fibers doped with Nd, Dy, Ho, Er, Tm, and Yb at the temperature above 900 K. Peak intensities of thermal radiations from rare-earth doped SiO 2 fibers increase sensitively with temperature. Thermal activation energies of thermal radiations by f-f transitions seen in Nd, Dy, Ho, Er, Tm, and Yb doped SiO 2 fibers are smaller than those from SiO 2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu. Thermal radiation due to highly efficient f-f transitions in Nd, Dy, Ho, Er, Tm, and Yb ions emits more easily than usual thermal radiation process. Thermal radiations from rare-earth doped SiO 2 are potentially applicable for the fiber-optic thermometry above 900 K

Pectolinarigenin - A Flavonoid Compound from Cirsium Japonicum ...

African Journals Online (AJOL)

HP

/tjpr.v13i2.9. Original Research Article. Pectolinarigenin - A Flavonoid Compound from Cirsium. Japonicum with Potential Anti-proliferation Activity in MCF-. 7 Breast Cancer Cell. Mingqian Lu. 1,2,3. , Qingzhi Kong. 1,4. *, Xinhua Xu. 2,3.

Yb-doped aluminophosphosilicate ternary fiber with high efficiency and excellent laser stability

Science.gov (United States)

Li, Yuwei; Peng, Kun; Zhan, Huan; Liu, Shuang; Ni, Li; Wang, Yuying; Yu, Juan; Wang, Xiaolong; Wang, Jianjun; Jing, Feng; Lin, Aoxiang

2018-03-01

By using chelate precursor doping technique and traditional modified chemical vapor deposition system, we fabricated Yb-doped aluminophosphosilicate (Al2O3-P2O5-SiO2, ternary Yb-APS) large-mode-area fiber and reported on its laser performance. The fiber preform was doped with Al, P and Yb with concentration of ∼8000 ppm, ∼1700 ppm and ∼400 ppm in molar percent, respectively. Tested with master oscillator power amplifier system, the home-made Yb-APS fiber was found to present 1.02 kW at 1061.1 nm with a high slope efficiency of 81.2% and excellent laser stability with power fluctuation less than ±1.1% for over 10 h. Compared with Yb-doped aluminosilicate (Al2O3-SiO2, binary Yb-AS) fiber, the introduction of P2O5 effectively suppressed photodarkening effect even the P/Al ratio is much less than 1, indicating that Yb-APS fiber is a better candidate for high power fiber lasers.

Substitution studies of Mn and Fe in Ln{sub 6}W{sub 4}Al{sub 43} (Ln=Gd, Yb) and the structure of Yb{sub 6}Ti{sub 4}Al{sub 43}

Energy Technology Data Exchange (ETDEWEB)

Treadwell, LaRico J.; Watkins-Curry, Pilanda [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080 (United States); McAlpin, Jacob D. [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Prestigiacomo, Joseph; Stadler, Shane [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Chan, Julia Y., E-mail: Julia.Chan@utdallas.edu [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080 (United States)

2014-02-15

The synthesis and characterization of Mn- and Fe-substituted Ln{sub 6}W{sub 4}Al{sub 43} (Ln=Gd, Yb) and Yb{sub 6}Ti{sub 4}Al{sub 43} are reported. The compounds adopt the Ho{sub 6}Mo{sub 4}Al{sub 43} structure type with lattice parameters of a∼11 Å and c∼17.8 Å with structural site preferences for Mn and Fe. The magnetization of Yb{sub 6}W{sub 4}Al{sub 43} is sensitive to Mn and Fe doping, which is evident by an increase in the field dependent magnetization. Gd{sub 6}W{sub 4}Al{sub 43}, Gd{sub 6}W{sub 4}Al{sub 42.31(11)}Mn{sub 0.69(11)}, and Gd{sub 6}W{sub 4}Al{sub 41.69(12)}Fe{sub 1.30(12)} order antiferromagnetically in the ab- and c-directions at 15, 14, and 13 K, respectively, with positive Weiss constants, suggesting the presence of ferromagnetic exchange interactions. Anisotropic magnetization data of Gd{sub 6}W{sub 4}Al{sub 43−y}T{sub y} (T=Mn, Fe) analogs are discussed. - Graphical abstract: The magnetic susceptibility of Ln{sub 6}W{sub 4−x}Al{sub 43−y}T{sub x+y} (Ln = Gd, Yb; T= Mn, Fe). Display Omitted - Highlights: • Single crystals of Ln{sub 6}W{sub 4−x}Al{sub 43−y}T{sub x+y} were grown with Al-flux. • Anisotropic magnetic behavior were determined on single crystals. • Gd{sub 6}W{sub 4−x}Al{sub 43−y}T{sub x+y} (T=Mn, Fe) analogs order antiferromagnetically.

Low-energy spin fluctuations in the non-Fermi-liquid compound YbRh2Si2

Directory of Open Access Journals (Sweden)

O. Stockert et al

2007-01-01

Full Text Available We report on inelastic neutron scattering experiments on YbRh2Si2 powder to study the low-energy spin dynamics at temperatures between T=0.8 and 22 K. The low-energy magnetic response is quasielastic. However, it exhibits an unusual form not modelled by a simple relaxation rate yielding a Lorentzian lineshape, but can satisfactorily be described by a phenomenological model involving a distribution of relaxation rates. The lower bound of the relaxation rates varies roughly linear with temperature indicating a pronounced slowing down of the critical modes above the antiferromagnetic ordering temperature TNapprox70 mK.

YbNi{sub 4}P{sub 2}. Single crystal growth by the Czochralski method and high-field magnetization measurements

Energy Technology Data Exchange (ETDEWEB)

Kliemt, Kristin; Krellner, Cornelius [Goethe-University, Frankfurt (Germany); Foerster, Tobias [HLD, Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Brando, Manuel [MPI for Chemical Physics of Solids, Dresden (Germany)

2016-07-01

We have investigated a new generation of YbNi{sub 4}P{sub 2} single crystals that were grown from a levitating melt by the Czochralski method. With T{sub C}= 0.17 K, this ferromagnetic material has the lowest Curie temperature ever observed among stoichiometric compounds. A quantum critical point occurs in the substitution series YbNi{sub 4}(P{sub 1-x}As{sub x}){sub 2} at x ∼ 0.1. The hybridization between localized f-electrons and the conduction electrons leads to a Fermi-liquid ground state with narrow bands and strongly enhanced effective electronic masses (heavy fermion system, Kondo temperature 8 K). An external magnetic field can split the bands, deform the Fermi surface and simultaneously suppress the Kondo interaction. If such a deformation changes the topology, it is called a Lifshitz transition. Previous thermodynamic and electrical transport studies have found indications for Lifshitz transitions in this Kondo lattice system. We report on results of high-field magnetization measurements at low temperature to further investigate the putative Lifshitz transitions in YbNi{sub 4}P{sub 2}.

Coexistence of metallic and insulating channels in compressed YbB6

Science.gov (United States)

Ying, Jianjun; Tang, Lingyun; Chen, Fei; Chen, Xianhui; Struzhkin, Viktor V.

2018-03-01

It remains controversial whether compressed YbB6 material is a topological insulator or a Kondo topological insulator. We performed high-pressure transport, x-ray diffraction (XRD), x-ray absorption spectroscopy, and Raman-scattering measurements on YbB6 samples in search for its topological Kondo phase. Both high-pressure powder XRD and Raman measurements show no trace of structural phase transitions in YbB6 up to 50 GPa. The nonmagnetic Yb2 + gradually change to magnetic Yb3 + above 18 GPa concomitantly with the increase in resistivity. However, the transition to the insulating state occurs only around 30 GPa, accompanied by the increase in the shear stress, and anomalies in the pressure dependence of the Raman T2 g mode and in the B atomic position. The resistivity at high pressures can be described by a model taking into account coexisting insulating and metallic channels with the activation energy for the insulating channel about 30 meV. We argue that YbB6 may become a topological Kondo insulator at high pressures above 35 GPa.

Encapsulation of a radiolabeled cluster inside a fullerene cage, (177)Lu(x)Lu((3-x))N@C(80): an interleukin-13-conjugated radiolabeled metallofullerene platform.

Science.gov (United States)

Shultz, Michael D; Duchamp, James C; Wilson, John D; Shu, Chun-Ying; Ge, Jiechao; Zhang, Jianyuan; Gibson, Harry W; Fillmore, Helen L; Hirsch, Jerry I; Dorn, Harry C; Fatouros, Panos P

2010-04-14

In this communication, we describe the successful encapsulation of (177)Lu into the endohedral metallofullerene (177)Lu(x)Lu(3-x)N@C(80) (x = 1-3) starting with (177)LuCl(3) in a modified quartz Kraschmer-Huffman electric generator. We demonstrate that the (177)Lu (beta-emitter) in this fullerene cage is not significantly released for a period of up to at least one-half-life (6.7 days). We also demonstrate that this agent can be conjugated with an interleukin-13 peptide that is designed to target an overexpressed receptor in glioblastoma multiforme tumors. This nanoparticle delivery platform provides flexibility for a wide range of radiotherapeutic and radiodiagnostic multimodal applications.

Phase precipitation of Yb 2+ ions in RbCl monocrystals monitored ...

African Journals Online (AJOL)

Optical absorption spectra of RbCl:Yb2+ crystals have been measured at several elevated temperatures up to 300C. Results showed that in hot RbCl:Yb2+ crystals, the Yb2+ ions occupied lattice sites with effective octahedral, O, point symmetry. Values of an energy parameter , which is an approximate measure of the ...

Electrodynamically trapped Yb+ ions for quantum information processing

International Nuclear Information System (INIS)

Balzer, Chr.; Braun, A.; Hannemann, T.; Wunderlich, Chr.; Paape, Chr.; Ettler, M.; Neuhauser, W.

2006-01-01

Highly efficient, nearly deterministic, and isotope selective generation of Yb + ions by one- and two-color photoionization is demonstrated. State preparation and state selective detection of hyperfine states in 171 Yb + is investigated in order to optimize the purity of the prepared state and to time-optimize the detection process. Linear laser-cooled Yb + ion crystals confined in a Paul trap are demonstrated. Advantageous features of different previous ion trap experiments are combined, while at the same time the number of possible error sources is reduced by using a comparatively simple experimental apparatus. This opens a new path toward quantum state manipulation of individual trapped ions, and in particular, to scalable quantum computing

Investigation of optical properties and the photocatalytic activity of synthesized YbYO4 nanoparticles and YbVO4/NiWO4 nanocomposites by polymeric capping agents

Science.gov (United States)

Pourmasoud, Saeid; Sobhani-Nasab, Ali; Behpour, Mohsen; Rahimi-Nasrabadi, Mehdi; Ahmadi, Farhad

2018-04-01

YbVO4 nanoparticles YbVO4/NiWO4 nanocomposites were synthesized by simple and new method. The effect of various polymeric capping agents such as Tween 80, Tween 20 and PEG on the shape and size of YbVO4/NiWO4 nanocomposites were investigated. YbVO4/NiWO4 nanocomposites were analyzed through some techniques including, X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM), thermogravimetry differential thermal analysis (TG-DTA), transmission electron microscopy (TEM), field emission electron microscopy (FESEM), ultraviolet-visible spectroscopy (UV-Vis), and energy-dispersive X-ray spectroscopy (EDX). This attempt is the first study on the photocatalytic performance of the YbVO4/NiWO4 nanocomposites in various conditions such as size of particles and kind of dyes (rhodamine B (Rh B), methylene blue (MB), methyl orange (MO), and phenol red (Ph R)), under visible light.

Down-conversion luminescence from (Ce, Yb) co-doped oxygen-rich silicon oxides

International Nuclear Information System (INIS)

Heng, C. L.; Wang, T.; Su, W. Y.; Wu, H. C.; Yin, P. G.; Finstad, T. G.

2016-01-01

We have studied down-conversion photoluminescence (PL) from (Ce, Yb) co-doped “oxygen rich” silicon oxide films prepared by sputtering and annealing. The Ce"3"+ ∼510 nm PL is sensitive to the Ce concentration of the films and is much stronger for 3 at. % Ce than for 2 at. % Ce after annealing at 1200 °C. The PL emission and excitation spectroscopy results indicate that the excitation of Yb"3"+ is mainly through an energy transfer from Ce"3"+ to Yb"3"+, oxide defects also play a role in the excitation of Yb"3"+ after lower temperature (∼800 °C) annealing. The Ce"3"+ 510 nm photon excites mostly only one Yb"3"+ 980 nm photon. Temperature-dependent PL measurements suggest that the energy transfer from Ce"3"+ to Yb"3"+ is partly thermally activated.

Study of the surrogate-reaction method applied to neutron-induced capture cross sections

International Nuclear Information System (INIS)

Boutoux, G.; Jurado, B.; Méot, V.; Roig, O.; Mathieu, L.; Aïche, M.; Barreau, G.; Capellan, N.; Companis, I.; Czajkowski, S.; Schmidt, K.-H.; Burke, J.T.; Bail, A.; Daugas, J.M.; Faul, T.; Morel, P.; Pillet, N.; Théroine, C.; Derkx, X.; Sérot, O.

2012-01-01

Gamma-decay probabilities of 173 Yb and 176 Lu have been measured using the surrogate reactions 174 Yb( 3 He,αγ) 173 Yb* and 174 Yb( 3 He,pγ) 176 Lu*, respectively. For the first time, the gamma-decay probabilities have been obtained with two independent experimental methods based on the use of C 6 D 6 scintillators and Germanium detectors. Our results for the radiative-capture cross sections are several times higher than the corresponding neutron-induced data. To explain these differences, we have used our gamma-decay probabilities to extract rather direct information on the spin distributions populated in the transfer reactions used. They are about two times wider and the mean values are 3 to 4 ℏ higher than the ones populated in the neutron-induced reactions. As a consequence, in the transfer reactions neutron emission to the ground and first excited states of the residual nucleus is strongly suppressed and gamma-decay is considerably enhanced.

Growth and continuous-wave laser operation of disordered crystals of Yb3+:NaLa(WO4)2 and Yb3+:NaLa(MoO4)2

International Nuclear Information System (INIS)

Liu, J.; Rico, M.; Griebner, U.; Petrov, V.; Cano-Torres, J.M.; Cascales, C.; Esteban-Betegon, F.; Serrano, M.D.; Volkov, V.; Zaldo, C.

2005-01-01

Single crystals of disordered NaLa(WO 4 ) 2 and NaLa(MoO 4 ) 2 doped with Yb 3+ are grown by the Czochralski method from the melt. Continuous-wave laser operation with Ti:sapphire laser pumping is demonstrated at room temperature without special cooling. Tunability from 1017 to 1057 nm and from 1015 to 1053 nm is achieved for Yb:NaLa(WO 4 ) 2 and Yb:NaLa(MoO 4 ) 2 , respectively. A maximum output power of 205 mW is obtained with Yb:NaLa(WO 4 ) 2 . (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

LU factorization for accelerator-based systems

KAUST Repository

Agullo, Emmanuel

2011-12-01

Multicore architectures enhanced with multiple GPUs are likely to become mainstream High Performance Computing (HPC) platforms in a near future. In this paper, we present the design and implementation of an LU factorization using tile algorithm that can fully exploit the potential of such platforms in spite of their complexity. We use a methodology derived from previous work on Cholesky and QR factorizations. Our contributions essentially consist of providing new CPU/GPU hybrid LU kernels, studying the impact on performance of the looking variants as well as the storage layout in presence of pivoting, tuning the kernels for two different machines composed of multiple recent NVIDIA Tesla S1070 (four GPUs total) and Fermi-based S2050 GPUs (three GPUs total), respectively. The hybrid tile LU asymptotically achieves 1 Tflop/s in single precision on both hardwares. The performance in double precision arithmetic reaches 500 Gflop/s on the Fermi-based system, twice faster than the old GPU generation of Tesla S1070. We also discuss the impact of the number of tiles on the numerical stability. We show that the numerical results of the tile LU factorization will be accurate enough for most applications as long as the computations are performed in double precision arithmetic. © 2011 IEEE.

Luminescence of YbP3O9 upon excitation in the UV-VUV range

International Nuclear Information System (INIS)

Stryganyuk, G; Trots, D; Berezovskaya, I; Shalapska, T; Voloshinovskii, A; Dotsenko, V; Zimmerer, G

2007-01-01

X-ray powder diffraction and luminescence spectral-kinetic studies have been performed for ytterbium metaphosphate (YbP 3 O 9 ) in the 12-290 K temperature range. The diffraction investigation has shown YbP 3 O 9 to be of monoclinic P 2 1 /c structure at T = 12-290 K. Charge transfer luminescence originating from Yb 3+ ion has been revealed. The carrier confinement within the Yb 3+ charge transfer state is pronounced at T = 12 K. A tendency has been revealed for charge carriers in YbP 3 O 9 to be localized in a trapped exciton state at room temperature. The quenching mechanisms for Yb 3+ charge transfer luminescence and processes competing with the formation of the Yb 3+ charge transfer state are discussed

Level structures in Yb nuclei far from stable nuclei

International Nuclear Information System (INIS)

Hashizume, Akira

1982-01-01

Applying n-γ, γ-γ coincidence techniques, the excited levels in 158 Yb and in 157 Yb nuclei were studied. Stress is placed ona neutron detection technique to assign (HI,xn) reactions which produce the nuclei far from β stability line. (author)

In-beam spectroscopy study of the proton emitter 151Lu

International Nuclear Information System (INIS)

Yu, C.; Rykaczewski, K.; Toth, K.S.; Akovali, Y.; Baktash, C.; Galindo-Uribarri, A.; Gross, C.J.; Paul, S.D.; Radford, D.C.; Batchelder, J.C.; Gross, C.J.; Bingham, C.R.; Grzywacz, R.; Kim, S.H.; Weintraub, W.; Ginter, T.N.; Grzywacz, R.; Rykaczewski, K.; Karny, M.; MacDonald, B.D.; Szerypo, J.

1998-01-01

Gamma rays decaying from the excited states of the proton-unbound 151 Lu were observed for the first time in an experiment using the 96 Ru( 58 Ni,p2n) 151 Lu reaction. These γ rays were identified by correlating prompt γ radiations at the target position with 151 Lu proton radioactivities at the focal plane of a recoil mass separator. Systematic data on N=80 isotones suggest a possible isomeric level at high spin in 151 Lu. Our measurement was unable to observe such an isomer, but provided an upper limit on its half-life. The observed γ rays in 151 Lu can be interpreted in terms of two possible level structures. copyright 1998 The American Physical Society

Electron spin resonance in YbRh2Si2: local-moment, unlike-spin and quasiparticle descriptions.

Science.gov (United States)

Huber, D L

2012-06-06

Electron spin resonance (ESR) in the Kondo lattice compound YbRh(2)Si(2) has stimulated discussion as to whether the low-field resonance outside the Fermi liquid regime in this material is more appropriately characterized as a local-moment phenomenon or one that requires a Landau quasiparticle interpretation. In earlier work, we outlined a collective mode approach to the ESR that involves only the local 4f moments. In this paper, we extend the collective mode approach to a situation where there are two subsystems of unlike spins: the pseudospins of the ground multiplet of the Yb ions and the spins of the itinerant conduction electrons. We assume a weakly anisotropic exchange interaction between the two subsystems. With suitable approximations our expression for the g-factor also reproduces that found in recent unlike-spin quasiparticle calculations. It is pointed out that the success of the local-moment approach in describing the resonance is due to the fact that the susceptibility of the Yb subsystem dominates that of the conduction electrons with the consequence that the relative shift in the resonance frequency predicted by the unlike-spin models (and absent in the local-moment models) is ≪ 1. The connection with theoretical studies of a two-component model with like spins is also discussed.

Biferroic LuCrO3: Structural characterization, magnetic and dielectric properties

International Nuclear Information System (INIS)

Durán, A.; Meza F, C.; Morán, E.; Alario-Franco, M.A.; Ostos, C.

2014-01-01

Multiferroic LuCrO 3 perovskite-type structure (Pbnm) obtained via auto-ignition synthesis was characterized by a combination of X-ray diffraction (XRD) and thermogravimetric (TG) techniques, and through magnetization and permittivity measurements. Results showed that amorphous combustion powders were fully transformed to orthorhombic LuCrO 3 structure at 1200 K after the first LuCrO 4 crystallization at 700 K. The magnetic response displays thermal irreversibility between zero-field-cooling and field-cooling condition which is due to spin canted AF switching at 116 K. Accordingly, a hysteresis loop in the M(H) data confirms weak ferromagnetism in LuCrO 3 . On the other hand, the permittivity measurement shows a broad peak transition typical of relaxor-type ferroelectrics transition at ∼450 K. Electrical conductivity increases as temperature increases showing an anomaly around the diffuse phase transition. The diffuse phase transition and the formation of the charge carriers are discussed in terms of a local distortion around the Lu Site. - Highlights: • Multiferroic LuCrO 3 was successfully obtained via auto-ignition synthesis. • Amorphous powder is transformed first to LuCrO 4 (700 K) and next to LuCrO 3 (1100 K). • The CrO 6 octahedra are tilted away and rotates from the ideal octahedral shape. • LuCrO 3 exhibits a canted AFM transition (116 K) and a relaxor ferroelectric behavior. • Tilting and rotation of CrO 6 octahedra influenced transport properties on LuCrO 3

Mixed Messages from Garnet Lu-Hf and Sm-Nd Geochronology

Science.gov (United States)

Vervoort, J. D.; Wang, D.; Johnson, T. A.

2017-12-01

Garnet geochronology provides important information on the timing and conditions of metamorphism. As a major indicator mineral formed during metamorphism, its direct dating can not only help establish the timing of metamorphism, provide the "t" for P-T-t paths, but also, if the dated garnet can be placed in a textural context, can provide information on the timing of deformational features. With advances in chemistry and mass spectrometry, garnet Lu-Hf and Sm-Nd geochronology has become an important geochronological tool and we can now reliably (if not routinely) date a wide variety of garnet compositions formed under diverse conditions. In the course of dating a variety of lithologies using both Lu-Hf and Sm-Nd isotope systems, however, some intriguing results have emerged. Although there are many examples where the Lu-Hf and Sm-Nd systems give the same date within uncertainty, there are also many cases where these systems yield significantly different dates, and the differences between these dates can be considerable—many 10's of Ma of and even 100's of Ma. For example, in garnet-bearing Mesoproterozoic gneisses from across the Blue Ridge Province in Virginia, both Lu-Hf and Sm-Nd analyses (determined on the same solutions) define narrow time spans, but with the Sm-Nd dates systematically younger (for orthogneisses Lu-Hf dates are 1032 to 1019 Ma whereas Sm-Nd dates are 965 to 949 Ma—a difference of 67 to 80 Ma). There are many other examples of systematically younger Sm-Nd garnet dates in both the literature and with our ongoing research. Potential explanations for these differences include: 1) strong partitioning of Lu into garnet during growth yielding ages weighted toward the beginning of growth; 2) faster Lu diffusion from high Lu regions after garnet formation, potentially leading to isochron rotation and anomalously old Lu-Hf dates; and 3) differences in closure temperatures of the two isotope systems. We will review several examples of divergent Lu

Mälu Instituut uurib inimõiguste rikkumisi

Index Scriptorium Estoniae

2008-01-01

President Toomas Hendrik Ilvese eestvedamisel asutati 20. sajandi teisel poolel Eestis toimunu põhjalikumaks uurimiseks Eesti Mälu Instituut. Ilmunud ka: Eesti Päevaleht (Stockholm) 14. veebr. 2008, lk. 2, pealk.: Mälu Instituut alustas tegevust; Vaba Eesti Sõna 7. veebr. 2008, lk. 12, pealk.: Under the leadership of President Ilves, the Memory Institute was established

Theoretical and experimental study of high-magnetic-field XMCD spectra at the L2,3 absorption edges of mixed-valence rare-earth compounds

International Nuclear Information System (INIS)

Kotani, Akio; Matsuda, Yasuhiro H; Nojiri, Hiroyuki

2009-01-01

X-ray magnetic circular dichroism(XMCD) spectra at the L 2,3 edges of mixed-valence rare-earth compounds in high magnetic fields are studied both theoretically and experimentally. The theoretical study is based on a new framework proposed recently by Kotani. The Zeeman splitting of 4f states, the mixed-valence character of 4f states, and the 4f-5d exchange interaction are incorporated into a single impurity Anderson model. New XMCD experiments in high magnetic fields up to 40 T are carried out for the mixed-valence compounds EuNi 2 (Si 0.18 Ge 0.82 ) 2 and YbInCu 4 by using a miniature pulsed magnet, which was developed recently by Matsuda et al. The XMCD data are taken at 5 K by transmission measurements for incident X-rays with ± helicities at BL39XU in SPring-8. After giving a survey on recent developments in the theory of XMCD spectra for mixed-valence Ce and Yb compounds, we calculate the XMCD spectra of YbInCu 4 at the field-induced valence transition around 32 T by applying the recent theoretical framework and by newly introducing at 32 T a discontinuous change in the Yb 4f level and that in the hybridization strength between the Yb 4f and conduction electrons. The calculated results are compared with the experimental ones.

Crystal growth, optical properties, and laser operation of Yb3+-doped NYW single crystal

Science.gov (United States)

Cheng, Y.; Xu, X. D.; Yang, X. B.; Xin, Z.; Cao, D. H.; Xu, J.

2009-11-01

Laser crystal Yb3+-doped NaY(WO4)2 (Yb:NYW) with excellent quality has been grown by Czochralski technique. The rocking curves from (400) plane of as-grown Yb:NYW crystal was measured and the full-width value at half-maximum was 19.92″. The effective segregation coefficients were measured by the X-ray fluorescence method. The polarized absorption spectra and the fluorescence spectra of Yb:NYW crystal were measured at room temperature. The fluorescence decay lifetime of Yb3+ ion in NYW crystal has been investigated. The spectroscopic parameters of Yb:NYW crystal are calculated and compared with those of Yb:YAG crystal. A continuous wave output power of 3.06 W at 1031 nm was obtained with a slope efficiency of 42% by use of diode pumping.

YB0 HAS LANDED

CERN Multimedia

  On Feb 28th after a majestic descent of 90m taking 11 hours, the 2000t YB0 central wheel of CMS, containing the superconducting solenoid, gently touched down on the floor of the experimental cavern UXC55.

Spectral-converting behaviors of Er{sup 3+} and Er{sup 3+}–Yb{sup 3+} doped YOCl phosphors

Energy Technology Data Exchange (ETDEWEB)

Park, Sangmoon, E-mail: spark@silla.ac.kr [Center for Green Fusion Technology and Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Cho, So-Hye [Center for Materials Architecturing, Institute of Multidisciplinary Convergence of Materials, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)

2014-01-25

Highlights: • Luminescent materials of YOCl:Er,Yb were prepared using NH{sub 4}Cl flux. • Interesting spectral-converting behaviors were observed in the phosphors. • 980 or 1550 nm diode laser was irradiated for up-converting study. • A multi-photon process in the phosphors was calculated. -- Abstract: Luminescent materials composed of Y{sub 1−m−n}Er{sub m}Yb{sub n}OCl (m = 0.001–0.1, n = 0.005–0.1) were prepared via a solid-state reaction using NH{sub 4}Cl flux. Photoluminescence spectra, the dependence of the luminescent intensity as a function of Er{sup 3+} content, and their CIE coordinates of the Er{sup 3+}-doped layered YOCl compounds were also investigated under near-ultraviolet (NUV) and visible lights. The spectral up-converting properties of Er{sup 3+} and Er{sup 3+}–Yb{sup 3+} in YOCl phosphors were elucidated under 980 and 1550 nm diode laser irradiations. This up-conversion emission spectra and the pump power dependence versus emission intensity observed in the Y{sub 0.9}Er{sub 0.1}OCl up-conversion phosphors gave rise to one- and two-photon processes. The up-conversion mechanism of Er{sup 3+} and Yb{sup 3+} ions in YOCl was described by a schematic energy-level diagram. Through the use of these up-conversion luminescent materials, the desired emitting lights throughout the orange and red regions of the spectra were achieved.

Synthesis and molecular structure of YbI(bipy)(DME)2 complex

International Nuclear Information System (INIS)

Petrovskaya, T.V.; Fedyushkin, I.L.; Nevodchikov, V.I.; Bochkarev, M.N.; Borodina, N.V.; Eremenko, I.L.; Nefedov, S.E.

1998-01-01

The reaction of the ytterbium naphthaline complex [Yb(DME) 2 ] 2 (μ-C 10 H 8 ) with 2,2 ' -bipyridine in DME is found to lead to the formation of the complex with the Yb 2+ atom, YbI(bipy)(DME) 2 (1) containing 2,2 ' -bipyridine radical anion. Complex 1 is characterized by IR and UV spectroscopy, magnetic methods and X-ray analysis [ru

Routes for synthesis and characterization of the Lu{sub 1-x}Ca{sub x}Cu{sub 2}Si{sub 2} series

Energy Technology Data Exchange (ETDEWEB)

Radaelli, Matheus; Piva, Mario Moda; Christovam, Denise S.; Ribeiro, Ana L.A.; Pagliuso, Pascoal G., E-mail: goiba@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

2016-07-01

Full text: New materials design always plays an important role in condensed matter physics. When CeCu{sub 2} Si{sub 2} was discovered,a new front in the field of superconductivity on strongly correlated materials started and led to the discovery of many classes of related materials. In such materials, the interplay between magnetism (affected by the hybridization strength between local f electrons and conduction electrons) and heavy-fermion superconductivity is still a matter of controversy and intense studies. Based on these materials, one can explore the structural and stoichiometric similarities among the several classes of related compounds to develop routes for new materials design of novel heavy fermion superconductors.The non-magnetic reference compound LuCu{sub 2}Si{sub 2} crystallizes in a ThCr{sub 2}Si{sub 2}-type structure (I4/mmm) and presents a metallic-like temperature dependent resistivity [2]. As such, it can be used as a based compound to search for 3d-based magnetic analogs of CeCu{sub 2}Si{sub 2}. In this work, we have performed Lu-site substitutions (Ba,Sr,Ca) in order to tune the orbital differentiation of the Cu 3d bands and potentially induce magnetism. We will discuss experiments of x-ray powder diffraction, elemental analysis (EDS, WDS), resistivity and DC magnetic susceptibility on single crystals Lu{sub 1-x}Ca{sub x}Cu{sub 2}Si{sub 2} (X{sub nominal} = 0, 0.3 and 0.5) grown from Tin-flux and evaluate the efficiency of different kinds of dopant to induce magnetism. (author)

Pressure dependence of the specific heat of heavy-fermion YbCu4.5

International Nuclear Information System (INIS)

Amato, A.; Fisher, R.A.; Phillips, N.E.; Jaccard, D.; Walker, E.

1990-03-01

The specific heat of a polycrystalline sample of YbCu 4.5 has been measured between 0.3 and 20K at pressures to 8.2 kbar. Unlike cerium-based heavy-fermion compounds, an increase of C/T is observed with increasing pressure, with the linear term enhanced by about 16% at 8.2 kbar. Above 7K, (∂C/∂P) T is negative. The nuclear contribution observed at P = 0 is increased by roughly a factor of two at 8.2 kbar. 7 refs., 3 figs

Polarized-neutron study of spin dynamics in the Kondo insulator YbB12.

Science.gov (United States)

Nemkovski, K S; Mignot, J-M; Alekseev, P A; Ivanov, A S; Nefeodova, E V; Rybina, A V; Regnault, L-P; Iga, F; Takabatake, T

2007-09-28

Inelastic neutron scattering experiments have been performed on the archetype compound YbB(12), using neutron polarization analysis to separate the magnetic signal from the phonon background. With decreasing temperature, components characteristic for a single-site spin-fluctuation dynamics are suppressed, giving place to specific, strongly Q-dependent, low-energy excitations near the spin-gap edge. This crossover is discussed in terms of a simple crystal-field description of the incoherent high-temperature state and a predominantly local mechanism for the formation of the low-temperature singlet ground state.

High-temperature thermopower of some REIn3 compounds

International Nuclear Information System (INIS)

Kletowski, Z.; Resel, R.

1995-01-01

The temperature dependences of the thermopower of six REIn 3 compounds (RE=La, Pr, Gd, Dy, Er and Lu) were measured in the temperature range up to 1000 K. The observed changes in the slopes of the temperature versus thermopower curves for all the investigated compounds are interpreted as originating from a special shape of the density of states (DOS) near the Fermi energy, E F . ((orig.))

Preparation, Biological Evaluation and Dosimetry Studies of 175Yb-Bis-Phosphonates for Palliative Treatment of Bone Pain

Directory of Open Access Journals (Sweden)

Ashraf Fakhari

2015-10-01

Full Text Available Objective: Optimized production and quality control of ytterbium-175 (Yb-175 labeled pamidronate and alendronate complexes as efficient agents for bone pain palliation has been presented. Methods: Yb-175 labeled pamidronate and alendronate (175Yb-PMD and 175Yb-ALN complexes were prepared successfully at optimized conditions with acceptable radiochemical purity, stability and significant hydroxyapatite absorption. The biodistribution of complexes were evaluated up to 48 h, which demonstrated significant bone uptake ratios for 175Yb-PAM at all-time intervals. It was also detected that 175Yb-PAM mostly washed out and excreted through the kidneys. Results: The performance of 175Yb-PAM in an animal model was better or comparable to other 175Yb-bone seeking complexes previously reported. Conclusion: Based on calculations, the total body dose for 175Yb-ALN is 40% higher as compared to 175Yb-PAM (especially kidneys indicating that 175Yb-PAM is probably a safer agent than 175Yb-ALN.

Controllable synthesis and crystal structure determined upconversion luminescence properties of Tm{sup 3+} (Er{sup 3+}) ions doped YbF{sub 3} and NaYbF{sub 4} crystals

Energy Technology Data Exchange (ETDEWEB)

Jiang, Tao [Institute of Photonics, Faculty of Science, Ningbo University, Ningbo 315211 (China); Qin, Weiping, E-mail: wpqin@jlu.edu.cn [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Zhou, Jun [Institute of Photonics, Faculty of Science, Ningbo University, Ningbo 315211 (China)

2014-04-01

Graphical abstract: - Highlights: • The synthesis of YbF{sub 3} and NaYbF{sub 4} crystals was successfully fulfilled by hydrothermal method. • The phase and morphology of products were adjusted by changing the hydrothermal conditions. • Relatively enhanced ultraviolet upconversion emissions were observed in YbF{sub 3} nanocrystals. • The crystalline phase impact on the upconversion luminescence was systematically studied. - Abstract: The synthesis of YbF{sub 3} and NaYbF{sub 4} crystals was successfully fulfilled by a facial hydrothermal method. The phase and morphology of the products were adjusted by changing the surfactant additive and fluorine source and tuning the pH value of the initial solution. The products with various morphologies range from octahedral nanoparticles, corn-like nanobundles, nanospheres, microrods, and hollow microprisms were prepared at different conditions. The growth mechanism of these products has been systematically studied. Impressively, relatively enhanced high order ultraviolet (UV) upconversion (UC) luminescence was observed in Tm{sup 3+} (Er{sup 3+}) ions doped YbF{sub 3} nanocrystals (NCs) compared with NaYbF{sub 4} microcrystals under the excitation of 980 nm infrared laser. The investigation results reveal that the crystal symmetry of matrix has significant effect on the spectra and lifetimes of the doping lanthanide ions. The simply synthesized water soluble YbF{sub 3} NCs with efficient UV UC luminescence may find potential application in biochemistry.

Luminescence properties and energy transfer processes in YAG:Yb,Er single crystalline films

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Savchyn, V.; Batentschuk, M.; Osvet, A.; Brabec, C.

2013-01-01

The paper is dedicated to the study of the optical properties of YAG:Yb,Er single-crystalline films (SCF) grown by liquid phase epitaxy. The absorption, cathodoluminescence and time-resolved photoluminescence spectra and photoluminescence decay curves were measured for the SCFs with different doping levels of Er 3+ (from 0.6 to 4.2 at.%) and Yb 3+ (from 0.1 to 0.6 at.%). The spectra, excited by synchrotron radiation in the fundamental absorption range of the YAG and in the intraionic absorption bands of both dopants, reveal energy transfer from the YAG host to the Er 3+ and Yb 3+ ions and between these ions. -- Highlights: •Growth of YAG:Yb,Er single crystalline films by LPE method. •Peculiarities of luminescence of YAG:Yb,Er films with different Er–Yb content. •Yb–Er energy transfer processes in YAG hosts

Synthesis and characterization of the novel rare earth orthophosphates Y0.5Er0.5PO4 and Y0.5Yb0.5PO4

International Nuclear Information System (INIS)

Schildhammer, Daniel; Petschnig, Lucas L.; Fuhrmann, Gerda; Heymann, Gunter; Schottenberger, Herwig; Huppertz, Hubert; Tribus, Martina

2016-01-01

The new mixed rare earth (RE) orthophosphates Y 0.5 Er 0.5 PO 4 and Y 0.5 Yb 0.5 PO 4 were synthesized by a classical solid state reaction in an electrical furnace at 1200 C. As starting materials, the corresponding rare earth oxides and diammonium hydrogen phosphate were used. The powder diffraction analyses revealed that the new compounds Y 0.5 Er 0.5 PO 4 and Y 0.5 Yb 0.5 PO 4 crystallize in a zircon-type structure being isostructural with the rare earth orthophosphate YPO 4 . Y 0.5 Er 0.5 PO 4 and Y 0.5 Yb 0.5 PO 4 crystallize in the tetragonal space group I4 1 /amd (no. 141) with four formula units in the unit cell. The structural parameters based on Rietveld refinements are a = 687.27(2), c = 601.50(2) pm, V = 0.28412(1) nm 3 , R p = 0.0143, and R wp = 0.0186 (all data) for Y 0.5 Er 0.5 PO 4 and a = 684.61(2), c = 599.31(2) pm, V = 0.28089(2) nm 3 , R p = 0.0242, and R wp = 0.0313 (all data) for Y 0.5 Yb 0.5 PO 4 . Furthermore, the structure of Y 0.5 Er 0.5 PO 4 was refined from single-crystal X-ray diffraction data: a = 687.78(5), c = 601.85(4) pm, V = 0.28470(5) nm 3 , R 1 = 0.0165, and wR 2 = 0.0385 (all data). In both compounds, the rare earth metal ions are eightfold coordinated by oxygen atoms, forming two unique interlocking tetrahedra with two individual RE-O distances. The tetrahedral phosphate groups [PO 4 ] 3- are slightly distorted in both compounds. The individual rare earth ions share a common position (Wyckoff site 4a). The presence of two rare earth ions in the structures of the new orthophosphates Y 0.5 Er 0.5 PO 4 and Y 0.5 Yb 0.5 PO 4 was additionally confirmed by single-crystal EDX spectroscopy revealing a ratio of 1:1.

Electronic, ductile, phase transition and mechanical properties of Lu-monopnictides under high pressures.

Science.gov (United States)

Gupta, Dinesh C; Bhat, Idris Hamid

2013-12-01

The structural, elastic and electronic properties of lutatium-pnictides (LuN, LuP, LuAs, LuSb, and LuBi) were analyzed by using full-potential linearized augmented plane wave within generalized gradient approximation in the stable rock-salt structure (B1 phase) with space group Fm-3m and high-pressure CsCl structure (B2 phase) with space group Pm-3m. Hubbard-U and spin-orbit coupling were included to predict correctly the semiconducting band gap of LuN. Under compression, these materials undergo first-order structural transitions from B1 to B2 phases at 241, 98, 56.82, 25.2 and 32.3 GPa, respectively. The computed elastic properties show that LuBi is ductile by nature. The electronic structure calculations show that LuN is semiconductor at ambient conditions with an indirect band gap of 1.55 eV while other Lu-pnictides are metallic. It was observed that LuN shows metallization at high pressures. The structural properties, viz, equilibrium lattice constant, bulk modulus and its pressure derivative, transition pressure, equation of state, volume collapse, band gap and elastic moduli, show good agreement with available data.

Preparation of 177Lu-DTPA-BIS-BIOTIN and biodistribution evaluation in normal mice

International Nuclear Information System (INIS)

Deng Xinrong; Luo Zhifu; Du Jin

2010-01-01

The labeling method for 177 Lu-DTPA-BIS-BIOTIN was established, and the biodistribution of 177 Lu-DTPA-BIS-BIOTIN in normal mice was carried out as well. Under the optimal experimental condition (DTPA-BIS-BIOTIN 25 μg, pH=4.5 reacting at 80 degree C for 20 min), the labeling yield of 177 Lu-DTPA-BIS-BIOTIN is more than 99.0%. 177 Lu-DTPA-BIS-BIOTIN shows pretty good in vitro stability. The biodistribution of 177 Lu-DTPA-BIS-BIOTIN in normal mice shows a rapid blood clearance. The uptake of 177 Lu-DTPA-BIS-BIOTIN is mainly accumulated in liver, spleen and kidney. 177 Lu-DTPA-BIS-BIOTIN is excreted by kidney. The results provide the basis for further study on 177 Lu-DTPA-BIS-BIOTIN used in pretargeted radioimage and radiotherapy of cancer. (authors)

Effects of Yb on the mechanical properties and microstructures of an Al-Mg alloy

International Nuclear Information System (INIS)

Song Min; Wu Zhenggang; He Yuehui

2008-01-01

This paper reported a first study of the effects of Yb on the microstructures and mechanical properties of an extruded Al-Mg alloy. It has been shown that the addition of 0.3 wt.% Yb decreases the mechanical properties of the alloy since Mg- and Yb-containing constituents decrease the concentration of Mg solute atoms in Al matrix, and thus the solution strengthening effect. However, the addition of 1 wt.% Yb substantially improves the mechanical behavior of the alloy because the concentration of Yb solute atoms in Al matrix is high enough to generate solution strengthening effect. The improvement in the mechanical properties is due to the large work-hardening and high dislocation density caused by the interaction between dislocations and Yb and Mg solute atoms. The Yb and Mg atoms inhibit the dynamic recovery and recrystallization of the alloy, thus provide a uniformly distributed dislocation structure with high density

Constants of hyperfine interaction of lanthanoid-phosphorus for [LnCl2Hmpa4]BPh4 composition compounds from data on 1H and 31P NMR

International Nuclear Information System (INIS)

Skopenko, V.V.; Amirkhanov, V.M.; Turov, A.V.; Trachevskij, V.V.

1991-01-01

By the method of 1 H and 31 P NMR at 233 and 298 K acetone solutions of lanthanide complexes of the composition [LnCl 2 Hmpa 4 ]BPh 4 (Hmpa=OP[N(CH 3 ) 2 ] 3 , Ln=La, Ce-Lu) have been considered. Two series of complexes having similar structure of coordination sphere (Ln=Pr-Ho and Ln=Er-Yb) are revealed and for each series the values of hyperfine interaction constants, which are 0.49 and 0.28 MHz respectively, have been determined

Excited negative parity bands in 160Yb

Science.gov (United States)

Saha, A.; Bhattacharjee, T.; Curien, D.; Dedes, I.; Mazurek, K.; Banerjee, S. R.; Rajbanshi, S.; Bisoi, A.; de Angelis, G.; Bhattacharya, Soumik; Bhattacharyya, S.; Biswas, S.; Chakraborty, A.; Das Gupta, S.; Dey, B.; Goswami, A.; Mondal, D.; Pandit, D.; Palit, R.; Roy, T.; Singh, R. P.; Saha Sarkar, M.; Saha, S.; Sethi, J.

2018-03-01

Negative parity rotational bands in {} 70160Yb{}90 nucleus have been studied. They were populated in the 148Sm(16O, 4n)160Yb reaction at 90 MeV. The gamma-coincidence data have been collected using Indian National Gamma Array composed of twenty Compton suppressed clover germanium (Ge) detectors. Double gating on triple gamma coincidence data were selectively used to develop the decay scheme for these negative parity bands by identifying and taking care of the multiplet transitions. The even- and odd-spin negative parity bands in 160Yb have been studied by comparing the reduced transition probability ratios with the similar bands in neighbouring even-even rare earth nuclei. It is concluded that the concerned odd-spin and even-spin bands are not signature partners and that their structures are compatible with those of the ‘pear-shape’ and ‘pyramid-shape’ oscillations, respectively, the octupole shapes superposed with the quadrupole shape of the ground-state.

Production of {sup 177}Lu for targeted radionuclide therapy: Available options

Energy Technology Data Exchange (ETDEWEB)

Dah, Ashutosh [Isotope Production and Applications Division, Bhabha Atomic Research Centre (BARC), Mumbai (India); Pillai, Maroor Raghavan Ambikalmajan [Molecular Group of Companies. Kerala (India); Knapp, Furn F. Jr. [Medical Isotopes Program, Isotope Dept. Group, Oak Ridge National Laboratory (ORNL), Oak Ridge (United States)

2015-06-15

This review provides a comprehensive summary of the production of {sup 177}Lu to meet expected future research and clinical demands. Availability of options represents the cornerstone for sustainable growth for the routine production of adequate activity levels of {sup 177}Lu having the required quality for preparation of a variety of {sup 177}Lu-labeled radiopharmaceuticals. The tremendous prospects associated with production of {sup 177}Lu for use in targeted radionuclide therapy (TRT) dictate that a holistic consideration should evaluate all governing factors that determine its success. While both “direct” and “indirect” reactor production routes offer the possibility for sustainable {sup 177}Lu availability, there are several issues and challenges that must be considered to realize the full potential of these production strategies. This article presents a mini review on the latest developments, current status, key challenges and possibilities for the near future. A broad understanding and discussion of the issues associated with {sup 177}Lu production and processing approaches would not only ensure sustained growth and future expansion for the availability and use of {sup 177}Lu-labeled radiopharmaceuticals, but also help future developments.

Measurement of the cross sections for the 175Lu(n,2n)174m,gLu reaction

International Nuclear Information System (INIS)

Yu Weixiang; Zhao Wenrong; Lu Hanlin; Han Xiaogang

1998-01-01

The 175 Lu(n,2n) 174m,g Lu reaction is an important indicator. There are 10 sets of measured data since 1960 (total 58 experimental values). Most of the data are finished at 14 MeV with 20%∼30% discrepancy. So the authors measured the cross section by activation method in neutron energies of 14 MeV and 10∼12 MeV. The measurement is carried out at the Cockcroft-Walton and HI-13 Tandem accelerator of CIAE

High-Spin Structure in Odd-Odd 160Lu Nucleus

International Nuclear Information System (INIS)

Wang Lie-Lin; Lu Jing-Bin; Yang Dong; Ma Ke-Yan; Yin Li-Chang; Zhou Yin-Hang; Wu Xiao-Guang; Wen Shu-Xian; Li Guang-Sheng; Yang Chun-Xiang

2012-01-01

The high-spin states of 160 Lu are populated by the fusion-evaporation reaction 144 Sm( 19 F,3n) 160 Lu at beam energies of 90 and 106 MeV. A new level scheme of 160 Lu is established. A possible isomeric state based on the πh 11/2 νh 9/2 configuration is observed. The new decoupled band with the configuration of πd 3/2 [411]1/2 + νi 13/2 [660]1/2 + is established, and the configurations of these similar decoupled bands in the neighboring odd-odd 162−166 Lu nuclei are suggested. A positive parity coupled band is assigned as the πd 5/2 [402]5/2 + νi 13/2 [660]1/2 + configuration. (nuclear physics)

Lifetime-broadening-suppressed X-ray absorption spectrum of β-YbAlB4 deduced from Yb 3d → 2p resonant X-ray emission spectroscopy

International Nuclear Information System (INIS)

Kawamura, Naomi; Mizumaki, Masaichiro; Kanai, Noriko; Hayashi, Hisashi; Matsuda, Yasuhiro H.; Kuga, Kentaro; Nakatsuji, Satoru; Watanabe, Shinji

2017-01-01

In this work, the Yb 3d → 2p (Yb Lα 1,2 ) resonant X-ray emission spectrum of β-YbAlB 4 was acquired using excitation energies around the Yb L 3 -edge, at 2 K. Subsequently, the lifetime-broadening-suppressed (LBS) X-ray absorption structure (XAS) spectrum was obtained using the SIM-RIXS program. This spectrum was found to exhibit clearly resolved pre-edge and shoulder structures. Resonant Lα 1 emission spectra were well reproduced from LBS-XAS profiles over wide ranges of excitation and emission energies. In contrast, noticeable discrepancies appeared between the experimental and simulated Lα 2 emission spectra, suggesting an effect resulting from M 4 M 5 O 1 Coster-Kronig transitions. LBS-XAS, in conjunction with partial fluorescence yield (PFY) XAS and transmission XAS, determined a value for the Yb valence (v) in β-YbAlB 4 of 2.76 ± 0.08 at 2 K. Despite this relatively large uncertainty in v, each method provided a consistent variation in valence (δv) as the temperature was raised from 2 to 280 K: 0.060 ± 0.004 (LBS-XAS), 0.061 ± 0.005 (PFY-XAS) and 0.058 ± 0.007 (transmission XAS). The smaller δv associated with LBS-XAS demonstrates the greater precision of this method. (author)

Is YbAs a heavy Fermion system?

International Nuclear Information System (INIS)

Monnier, R.; Degiorgi, L.; Delley, B.; Koelling, D.D.

1989-08-01

Using parameters extracted from a tight binding fit to an ab initio band structure, the specific heat anomaly observed in YbAs around 5 K is computed within the infinite U limit of the degenerate Anderson impurity model. Applying the renormalization procedure derived in variational treatments of the periodic Anderson model, a quasiparticle Fermi surface with strong nesting features and small mass enhancements is obtained. The results suggest that YbAs is not a ''classical'' heavy Fermion system. 28 refs., 3 figs., 1 tab

Cooperative up-conversion processes in SrAl{sub 4}O{sub 7}:Yb and SrAl{sub 4}O{sub 7}:Yb,Tb and their dependence on charge compensation by Na

Energy Technology Data Exchange (ETDEWEB)

Puchalska, M., E-mail: malgorzata.puchalska@chem.uni.wroc.pl [Faculty of Chemistry, University of Wroclaw, 14, F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zych, E. [Faculty of Chemistry, University of Wroclaw, 14, F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Watras, A. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna Street, 50-422 Wrocław (Poland)

2017-03-15

A detailed analysis of the luminescence behaviour of Yb{sup 3+}-doped and Yb{sup 3+}-Tb{sup 3+} co-doped strontium aluminates powders: Sr{sub 1-x}Yb{sub x}Al{sub 4}O{sub 7} (x=0.002–0.07) and Sr{sub 1-x-y}Yb{sub x}Tb{sub y}Al{sub 4}O{sub 7} (x=0.03; y=0.002–0.02) were performed. The studies of singly doped samples show that direct excitation of Yb{sup 3+} by means of {sup 2}F{sub 7/2}-{sup 2}F{sub 5/2} absorption at 900–980 nm leads to Stokes Yb{sup 3+} emission in the range of 970–1130 nm as well as bluish-green Yb{sup 3+} cooperative luminescence (CL) whose energy doubles that of the NIR one. The effect of activator concentration and charge compensation through Na{sup +} co-doping on both Yb{sup 3+} emissions were also studied. It was found that Na{sup +} addition enhanced Stokes Yb{sup 3+} photoluminescence brightness, while the cooperative emission intensity appeared to be lower. In doubly Yb{sup 3+}-Tb{sup 3+} doped materials excitation at 980 nm led to cooperative sensitization of the Tb{sup 3+} {sup 5}D{sub 4} level giving rise to its green {sup 5}D{sub 4}→{sup 7}F{sub J} (J={sup 7}F{sub 6}-{sup 7}F{sub 3}) up-conversion luminescence with the dominant component around 542 nm. The cooperative energy transfer (CET) mechanism was proposed basing on the results obtained from emission and absorption spectra, decay kinetics as well as the dependence of UC luminescence intensity on NIR excitation power.

Biferroic LuCrO{sub 3}: Structural characterization, magnetic and dielectric properties

Energy Technology Data Exchange (ETDEWEB)

Durán, A., E-mail: dural@cnyn.unam.mx [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, Apartado Postal 14, C.P. 22800 Ensenada, BC (Mexico); Meza F, C.; Morán, E.; Alario-Franco, M.A. [Departamento de Química Inorgánica y Laboratorio Complutense de Altas Presiones, Facultad de Química, Universidad Complutense de Madrid, EU, 28040 Madrid (Spain); Ostos, C., E-mail: ceostoso@gmail.com [Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)

2014-02-14

Multiferroic LuCrO{sub 3} perovskite-type structure (Pbnm) obtained via auto-ignition synthesis was characterized by a combination of X-ray diffraction (XRD) and thermogravimetric (TG) techniques, and through magnetization and permittivity measurements. Results showed that amorphous combustion powders were fully transformed to orthorhombic LuCrO{sub 3} structure at 1200 K after the first LuCrO{sub 4} crystallization at 700 K. The magnetic response displays thermal irreversibility between zero-field-cooling and field-cooling condition which is due to spin canted AF switching at 116 K. Accordingly, a hysteresis loop in the M(H) data confirms weak ferromagnetism in LuCrO{sub 3}. On the other hand, the permittivity measurement shows a broad peak transition typical of relaxor-type ferroelectrics transition at ∼450 K. Electrical conductivity increases as temperature increases showing an anomaly around the diffuse phase transition. The diffuse phase transition and the formation of the charge carriers are discussed in terms of a local distortion around the Lu Site. - Highlights: • Multiferroic LuCrO{sub 3} was successfully obtained via auto-ignition synthesis. • Amorphous powder is transformed first to LuCrO{sub 4} (700 K) and next to LuCrO{sub 3} (1100 K). • The CrO{sub 6} octahedra are tilted away and rotates from the ideal octahedral shape. • LuCrO{sub 3} exhibits a canted AFM transition (116 K) and a relaxor ferroelectric behavior. • Tilting and rotation of CrO{sub 6} octahedra influenced transport properties on LuCrO{sub 3}.

Thermodynamic properties of multiferroic Mg doped YbMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Sattibabu, Bhumireddi, E-mail: bsb.satti@gmail.com [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Bhatnagar, A.K., E-mail: anilb42@gmail.com [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Samatham, S. Shanmukharao; Singh, D. [Low Temperature Laboratory, UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001, M.P. (India); Rayaprol, S. [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC Campus, Mumbai 400085 (India); Das, D. [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Siruguri, V. [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC Campus, Mumbai 400085 (India); Ganesan, V. [Low Temperature Laboratory, UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001, M.P. (India)

2015-09-25

Highlights: • Specific heat data shows that T{sub N} increases for Mg doped YbMnO{sub 3} from 83 K to 86 K. • Yb{sub 1−x}Mg{sub x}MnO{sub 3} (x = 0.0 and 0.05) shows multiple magnetic transitions. • RCP are found to be 26.1 J/mol and 27.2 J/mol for YbMnO{sub 3} and Yb{sub 0.95}Mg{sub 0.05}MnO{sub 3}. - Abstract: Calorimetric studies of polycrystalline samples Yb{sub 1−x}Mg{sub x}MnO{sub 3} with x = 0.0 and 0.05 are reported. It is revealed that the Mg doping raises the antiferromagnetic ordering temperature, T{sub N,} from 83 K for x = 0.0 to 86 K for x = 0.05. A ferromagnetic ordering is also observed around 3 K. The broad feature in the specific heat data just above ferromagnetic ordering, is attributed to the Schottky anomaly. The estimated effective molecular fields from the Schottky analysis are H{sub mf} = 3.0 and 3.5 T for YbMnO{sub 3} and Yb{sub 0.95}Mg{sub 0.05}MnO{sub 3}, respectively. High temperature shift of Schottky anomaly with Mg doping indicates increase in effective molecular field of Mn at the Yb 4b site. The data supports that the idea that although molecular field is mainly responsible for the Schottky anomaly in Yb{sub 1−x}Mg{sub x}MnO{sub 3} and Mn{sup 3+} spin ordering also affects it. Magnetic part of the specific heat is obtained by subtracting the lattice contribution estimated using two Debye temperatures. The magnetic entropy change (ΔS{sub mag}) for pure and doped samples are 2.0 J mol{sup −1} K{sup −1} and 2.1 J mol{sup −1} K{sup −1} respectively, while the relative cooling power (RCP) calculate 26.1 J/mol, 27.2 J/mol for a field change of 10 T.

Continuous-wave diode-pumped Yb 3+:LYSO tunable laser

Science.gov (United States)

Du, Juan; Liang, Xiaoyan; Xu, Yi; Li, Ruxin; Yan, Chengfeng; Zhao, Guangjun; Su, Liangbi; Xu, Jun; Xu, Zhizhan

2007-01-01

A new alloyed crystal, Yb:LYSO, has been grown by the Czochralski method in our institute for the first time, and its effective diode-pumped cw tunable laser action was demonstrated. The alloyed crystal retains excellent laser properties of LSO with reduced growth cost, as well as the favorable growth properties of YSO. With a 5-at.% Yb:LYSO sample, we achieved 2.84 W output power at 1085 nm and a slope efficiency of 63.5%. And its laser wavelength could be tuned over a range broader than 80nm, from 1030nm to 1111 nm. This is the broadest tunable range achieved for Yb:LYSO laser, as far as we know.

Optical and scintillating properties of Ce:Li(Y,Lu)F4 single crystals

International Nuclear Information System (INIS)

Yokota, Yuui; Kurosawa, Shunsuke; Chani, Valery; Kamada, Kei; Yoshikawa, Akira

2014-01-01

We have investigated the optical and scintillating properties of Lu co-doped Ce:LiYF 4 single crystals with various Lu content. In the transmittance and absorption spectra, the absorption peaks at 243 nm get systematically red shifted in contrast to the peaks at 197 and 200 nm which get blue shifted with the increase in Lu content. At the same time, emission peaks at 306 nm and 200 nm under 295 nm excitation also get red shifted. The decay time of Ce:Li(Y,Lu)F 4 crystals under 295 nm excitation is found to be faster than that of Ce:LiYF 4 and Ce:LiLuF 4 crystals. The alpha-peak positions in the pulse-height spectra and decay times of crystals under alpha-ray irradiation are found to vary with the Lu content. - Highlights: • Optical and scintillation properties of Ce:Li(Y 1-x Lu x )F 4 crystals were inspected. • Increase of Lu content resulted change of the position of four absorption peaks. • Admixing of Y and Lu decreased the light yield and increased the decay time. • The Ce:LiLuF 4 crystal indicated the largest light yield in the pulse-height spectra. • Li[(Y 0.8 Lu 0.2 ) 0.98 Ce 0.02 ]F 4 indicated larger light yield than Ce:LiYF 4 crystal

Intensities of two-quanta cascades at different excitation energies of compound nuclei 146Nd, 174Yb, 183W

International Nuclear Information System (INIS)

Boneva, S.T.; Khitrov, V.A.; Sukhovoj, A.M.; Vojnov, A.V.

1990-01-01

Intensities of two-quanta cascades are obtained for 2-3 final low-lying levels of the following nuclei 146 Nd, 174 Yb and 183 W. These measured intensities are compared with the intensities calculated in the frame of various models at primary transition energies ranging from 0.5 MeV to the neutron binding energy. Some excitation energy intervals are revealed, experimentally obtained intensities of cascade are inconsistent with model calculations. 15 refs.; 7 figs

Absence of justice : Lu Chengming's struggle for compensation

Energy Technology Data Exchange (ETDEWEB)

Bai, L.

2008-03-10

This article described the efforts of Chinese citizen Lu Chengming to claim compensation from the Chinese government after being forcibly re-located during the building of the Three Gorges hydroelectric project. Research conducted by the author revealed that many households were not compensated for being resettled, and that many people who had lived in the region became refugees. Lu Chengming's family became unemployed after his hotel was demolished in 2002. The family of 11 was then divided into 4 in order to further reduce the amount of subsidies owed to them. Appeals to higher authorities began in 1993. Since then, Lu Chengming has only received the most basic welfare assistance. This article provided a translation of Lu Chengming's testimony as well as his account of the resettlement procedures. It was concluded that while the Chinese government consistently refuses his claims, Lu Chengming continues to live in hope that the government will award him his settlement. 4 refs., 3 figs.

Yb:YAG Lasers for Space Based Remote Sensing

Science.gov (United States)

Ewing, J.J.; Fan, T. Y.

1998-01-01

Diode pumped solid state lasers will play a prominent role in future remote sensing missions because of their intrinsic high efficiency and low mass. Applications including altimetry, cloud and aerosol measurement, wind velocity measurement by both coherent and incoherent methods, and species measurements, with appropriate frequency converters, all will benefit from a diode pumped primary laser. To date the "gold standard" diode pumped Nd laser has been the laser of choice for most of these concepts. This paper discusses an alternate 1 micron laser, the YB:YAG laser, and its potential relevance for lidar applications. Conceptual design analysis and, to the extent possible at the time of the conference, preliminary experimental data on the performance of a bread board YB:YAG oscillator will be presented. The paper centers on application of YB:YAG for altimetry, but extension to other applications will be discussed.

Diode-pumped Yb:Sr5(PO4)3F laser performance

International Nuclear Information System (INIS)

Marshall, C.D.; Payne, S.A.; Smith, L.K.

1995-01-01

The performance of the first diode-pumped Yb 3+ -doped Sr 5 (PO 4 ) 3 F (Yb:S-FAP) laser is discussed. We found the pumping dynamics and extraction cross-sections of Yb:S-FAP crystals to be similar to those previously inferred by purely spectroscopic techniques. The saturation fluence for pumping was measured to be 2.2 J/cm 2 using three different methods based on either the spatial, temporal, or energy transmission properties of a Yb:S-FAP rod. The small signal gain implies an emission cross section of 6.0 x 10 -20 cm 2 that falls within error bars of the previously reported value of 7.3 x 10 -20 cm 2 , obtained from spectroscopic techniques. Up to 1.7 J/cm 3 of stored energy density was achieved in a 6 x 6 x 44 mm Yb:S-FAP amplifier rod. An InGaAs diode array has been fabricated that has suitable specifications for pumping a 3 x 3 x 30 mm Yb:S-FAP rod. In a free running configuration diode-pumped slope efficiencies up to 43% were observed with output energies up to ∼0.5 J per 1 ms pulse. When the rod was mounted in a copper block for cooling, 13 W of average power was produced with power supply limited operation at 70 Hz and 500 μs pulses

Luminescence and scintillation properties of LuPO4-Ce nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyy, T.; Pushak, A.; Vas’kiv, A.; Shapoval, A.; Mitina, N.; Gektin, A.; Zaichenko, A.; Voloshinovskii, A.

2014-01-01

Study of the spectral-luminescence parameters of LuPO 4 -Ce nanoparticles upon the excitation by X-ray quanta and synchrotron radiation with photon energies of 4–25 eV was performed. Nanoparticles with mean size about a=35 nm and nanoparticles with size less than 12 nm reveal the different structures of cerium centers. Luminescence efficiency of LuPO 4 -Ce nanoparticles of a 4 -Ce nanoparticles studied using synchrotron and X-ray excitation. • Different structure of Ce 3+ -centers has been revealed for LuPO 4 -Ce nanoparticles. • Luminescence of LuPO 4 -Ce with size less than 12 nm is strongly quenched upon the X-ray excitation

The recombination channels of luminescence excitation in YAG:Yb single crystalline films

International Nuclear Information System (INIS)

Zakharko, Ya.M.; Luchechko, A.P.; Ubizskii, S.B.; Syvorotka, I.I.; Martynyuk, N.V.; Syvorotka, I.M.

2007-01-01

Absorption and emission spectra, luminescence decay kinetics and thermostimulated luminescence of X-ray irradiated YAG:Yb single crystalline films were studied. Two emission bands peaked at 420 and 488 nm have been detected in the investigated films. The strong thermal quenching of luminescence band at 488 nm was observed above 160 K. The influence of growth conditions and annealing in air on the lifetime of Yb 3+ ion excited state in the IR spectral region have been revealed. The recombination mechanisms of the f-f transition at Yb 3+ ion excitation, as well as the mechanism of lifetime shortening for the excited Yb 3+ luminescence have been discussed

The infrared radiation spectrum of acupoint taiyuan (LU 9) in asthma patients.

Science.gov (United States)

Zhou, Yu; Shen, Xue-yong; Wang, Li-zhen; Wei, Jian-zi; Cheng, Ke

2012-06-01

To analyze the distinctive pathological characteristics in the spectrums of spontaneous infrared radiation at the Taiyuan (LU 9) acupoint in patients with asthma. A highly sensitive infrared spectrum detecting device was used to detect the spectrums of spontaneous infrared radiation at Taiyuan (LU 9) in 37 asthma patients and 34 healthy volunteers. Asthma patients had significantly lower infrared intensity than that of the healthy volunteers (P>0.01). Asthma patients had significantly lower overall infrared radiation intensity at the left Taiyuan (LU 9) than that of healthy volunteers (P > 0.05), but there was no significant difference between healthy volunteers and asthma patients at the right Taiyuan (LU 9) (P > 0.05). The infrared radiation intensity of 17 wavelength spots at the left Taiyuan (LU 9) and 4 wavelength spots at the right Taiyuan (LU 9) in asthma patients were significantly lower than those of healthy volunteers (P > 0.05). At 2 microm, the infrared radiation intensity of asthma patients was significantly stronger than that of healthy volunteers (P > 0.05). At 19 wavelength spots in the healthy volunteers and at 4 wave-length spots in the asthma patients, the left Taiyuan (LU 9) showed a significantly stronger intensity than that of the right Taiyuan (LU 9) (P > 0.05S). By Pearson's chi2 test, healthy volunteers had more wavelength spots that were significantly different between the left and right Taiyuan (LU 9) than the asthma patients (P > 0.01). Changes in the infrared spectrum at the Taiyuan (LU 9) acupoint in asthma patients may reflect distinct pathological changes. Certain acupuncture points may be related to specific organs.

Synthesis of DOTMP and biodistribution and imaging study of 177-Lu-DOTMP

International Nuclear Information System (INIS)

Deng Xinrong; Luo Zhifu; Xiang Xueqin; Li Fenglin; Fan Caiyun; Liu Zihua; Ye Zhaoyun; Li Hongyu; Chen Yang; Zhuang Ling

2012-01-01

Cyclen (1, 4, 7, 10-tetraazacyclododecane) and H 3 PO 3 was used to synthesis DOTMP (1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-Tetraamino methylenephosphonate). 177 Lu was produced by irradiating enriched lutetium oxide ( 176 Lu 2 O 3 ) with thermal neutron flux of 2' × 10 13 n/cm 2 /S in swimming pool reactor (SPR) for 10 days. And then DOTMP was labelled by 177 Lu. The biodistribution of 177 Lu-DOTMP in model mice bearing S180 sarcoma and SPECT imaging in Japanese white rabbit were also carried out. The results showed that the total activity of 177 LuCl 3 solution obtained was 9.19 × 10 5 MBq after corresponding chemical process. According to the optimal condition of the labeling experiment, the labelling efficiency of 177 Lu-DOTMP was 99.4%. The results of biodistribution study indicated that 177 Lu-DOTMP eliminated rapidly from blood and was delivered to target bone. The radioactivity uptake was mainly in bone and less in other viscera. The results of SPECT imaging showed that the radioactivity was accumulated in bladder. 177 Lu-DOTMP was mainly excreted by kidney. The uptake of the activity in the skeleton was observed within 22 h postinjection and it became quite significant at 46 h post injection. It indicated that 177 Lu-DOTMP has good bone targeting and is worthy of further research. (authors)

U-Pb and Lu-Hf systematics of zircons from Sargur metasediments, Dharwar Craton, Southern India: new insights on the provenance and crustal evolution

International Nuclear Information System (INIS)

Maibam, Bidyananda; Gerdes, Axel; Srinivasan, R.; Goswami, J.N.

2017-01-01

A study of U-Pb and Lu-Hf-Yb isotope data in zircons from metamorphosed psammopelite and quartzite from the type area of Archaean Sargur Group, Dharwar Craton, India is carried out. Two age populations are observed: an older population with concordant U-Pb ages between 2.7 and 2.8 Ga, and a younger population with ages in the 2.4 - 2.6 Ga age range. The εHf values of 0 to + 2.0 for the older zircon population suggest that they were derived from juvenile crust formed at 2.7- 2.8 Ga. Sub-chondritic εHf values for the younger population indicate metamorphism and/or crustal reworking at ∼2.5 Ga. Meta-sedimentary enclaves in the Sargur type area are therefore part of the gneiss-supracrustal complex of different antiquities and may not have an independent stratigraphic status. (author)

Observation of Vacancies, Faults, and Superstructures in Ln5Mo2O12 (Ln = La, Y, and Lu) Compounds with Direct Mo-Mo Bonding.

Science.gov (United States)

Colabello, Diane M; Sobalvarro, Elizabeth M; Sheckelton, John P; Neuefeind, Joerg C; McQueen, Tyrel M; Khalifah, Peter G

2017-11-06

Among oxide compounds with direct metal-metal bonding, the Y 5 Mo 2 O 12 (A 5 B 2 O 12 ) structural family of compounds has a particularly intriguing low-dimensional structure due to the presence of bioctahedral B 2 O 10 dimers arranged in one-dimensional edge-sharing chains along the direction of the metal-metal bonds. Furthermore, these compounds can have a local magnetic moment due to the noninteger oxidation state (+4.5) of the transition metal, in contrast to the conspicuous lack of a local moment that is commonly observed when oxide compounds with direct metal-metal bonding have integer oxidation states resulting from the lifting of orbital degeneracy typically induced by the metal-metal bonding. Although a monoclinic C2/m structure has been previously proposed for Ln 5 Mo 2 O 12 (Ln = La-Lu and Y) members of this family based on prior single crystal diffraction data, it is found that this structural model misses many important structural features. On the basis of synchrotron powder diffraction data, it is shown that the C2/m monoclinic unit cell represents a superstructure relative to a previously unrecognized orthorhombic Immm subcell and that the superstructure derives from the ordering of interchangeable Mo 2 O 10 and LaO 6 building blocks. The superstructure for this reason is typically highly faulted, as evidenced by the increased breadth of superstructure diffraction peaks associated with a coherence length of 1-2 nm in the c* direction. Finally, it is shown that oxygen vacancies can occur when Ln = La, producing an oxygen deficient stoichiometry of La 5 Mo 2 O 11.55 and an approximately 10-fold reduction in the number of unpaired electrons due to the reduction of the average Mo valence from +4.5 to +4.05, a result confirmed by magnetic susceptibility measurements. This represents the first observation of oxygen vacancies in this family of compounds and provides an important means of continuously tuning the magnetic interactions within the one

Bone targeting compounds for radiotherapy and imaging: *Me(III)-DOTA conjugates of bisphosphonic acid, pamidronic acid and zoledronic acid.

Science.gov (United States)

Meckel, M; Bergmann, R; Miederer, M; Roesch, F

2017-01-01

Bisphosphonates have a high adsorption on calcified tissues and are commonly used in the treatment of bone disorder diseases. Conjugates of bisphosphonates with macrocyclic chelators open new possibilities in bone targeted radionuclide imaging and therapy. Subsequent to positron emission tomography (PET) examinations utilizing 68 Ga-labelled analogues, endoradiotheraphy with 177 Lu-labelled macrocyclic bisphosphonates may have a great potential in the treatment of painful skeletal metastases. Based on the established pharmaceuticals pamidronate and zoledronate two new DOTA-α-OH-bisphosphonates, DOTA PAM and DOTA ZOL (MM1.MZ) were successfully synthesized. The ligands were labelled with the positron emitting nuclide 68 Ga and the β - emitting nuclide 177 Lu and compared in in vitro studies and in ex vivo biodistribution studies together with small animal PET and single photon emission computed tomography (SPECT) studies against [ 18 F]NaF and a known DOTA-α-H-bisphosphonate conjugate (BPAPD) in healthy Wistar rats. The new DOTA-bisphosphonates can be labelled in high yield of 80 to 95 % in 15 min with post-processed 68 Ga and >98 % with 177 Lu. The tracers showed very low uptake in soft tissue, a fast renal clearance and a high accumulation on bone. The best compound was [ 68 Ga]DOTA ZOL (SUV Femur  = 5.4 ± 0.6) followed by [ 18 F]NaF (SUV Femur  = 4.8 ± 0.2), [ 68 Ga]DOTA PAM (SUV Femur  = 4.5 ± 0.2) and [ 68 Ga]BPAPD (SUV Femur  = 3.2 ± 0.3). [ 177 Lu]DOTA ZOL showed a similar distribution as the diagnostic 68 Ga complex. The 68 Ga labelled compounds showed a promising pharmacokinetics, with similar uptake profile and distribution kinetics. Bone accumulation was highest for [ 68 Ga]DOTA ZOL , which makes this compound probably an interesting bone targeting agent for a therapeutic approach with 177 Lu. The therapeutic compound [ 177 Lu]DOTA ZOL showed a high target-to-background ratio. SPECT experiments showed concordance

Influence of dopant concentration on spectroscopic properties of Sr2CeO4:Yb nanocrystals

Science.gov (United States)

Stefanski, M.; Kędziorski, A.; Hreniak, D.; Strek, W.

2017-12-01

Optical properties of Sr2CeO4:Yb nanocrystals synthesized via Pechini's method are reported. The samples were characterized by X-ray diffraction data measurements. The unit cell parameters were determined using Rietveld refinement. It was found that they decreased with increasing amount of Yb ions. The absorption, excitation, emission spectra and luminescence decay profiles of the Sr2CeO4:Yb nanocrystals were investigated. It was observed that optical properties were strongly dependent on Yb concentration. It was found that Yb3+-O2- charge transfer transitions have great influence on the absorption spectra. It can be seen in the emission spectra that in addition to standard bands/lines corresponding to Ce-O metal-to-ligand charge transfer of Sr2CeO4 and f-f transitions of Yb3+, there is emission band centered at 744 nm. Its intensity depends on the concentration of the dopant. Recorded decay times become shorter with increasing dopant concentration due to the Yb3+ concentration quenching. Excitation spectra indicate the energy transfer from Ce-O charge transfer states to Yb3+2F5/2 state. The issue of appearance of down-conversion process in Sr2CeO4:Yb nanocrystals is considered.

Multispecies animal investigation on biodistribution, pharmacokinetics and toxicity of 177Lu-EDTMP, a potential bone pain palliation agent

International Nuclear Information System (INIS)

Mathe, Domokos; Balogh, Lajos; Polyak, Andras; Kiraly, Reka; Marian, Terez; Pawlak, Dariusz; Zaknun, John J.; Pillai, Maroor R.A.; Janoki, Gyozo A.

2010-01-01

Introduction: Radionuclide therapy (RNT) is an effective method for bone pain palliation in patients suffering from bone metastasis. Due to the long half-life, easy production and relatively low β- energy, 177 Lu [T 1/2 =6.73 days, E βmax =497 keV, E γ =113 keV (6.4%), 208 keV (11%)]-based radiopharmaceuticals offer logistical advantage for wider use. This paper reports the results of a multispecies biodistribution and toxicity studies of 177 Lu-EDTMP to collect preclinical data for starting human clinical trials. Methods: 177 Lu-EDTMP with radiochemical purity greater than 99% was formulated by using a lyophilized kit of EDTMP (35 mg of EDTMP, 5.72 g of CaO and 14.1 mg of NaOH). Biodistribution studies were conducted in mice and rabbits. Small animal imaging was performed using NanoSPECT/CT (Mediso, Ltd., Hungary) and digital autoradiography. Gamma camera imaging was done in rabbits and dogs. Four levels of activity (9.25 through 37 MBq/kg body weight) of 177 Lu-EDTMP were injected in four groups of three dogs each to study the toxicological effects. Results: 177 Lu-EDTMP accumulated almost exclusively in the skeletal system (peak ca. 41% of the injected activity in bone with terminal elimination half-life of 2130 and 1870 h in mice and rabbits, respectively) with a peak uptake during 1-3 h. Excretion of the radiopharmaceutical was through the urinary system. Imaging studies showed that all species (mouse, rat, rabbit and dog) take up the compound in regions of remodeling bone, while kidney retention is not visible after 1 day postinjection (pi). In dogs, the highest applied activity (37 MBq/kg body weight) led to a moderate decrease in platelet concentration (mean, 160 g/L) at 1 week pi with no toxicity. Conclusion: The protracted effective half-life of 177 Lu-EDTMP in bone supports that modifying the EDTMP molecule by introducing 177 Lu does not alter its biological behaviour as a specific bone-seeking tracer. Species-specific pharmacokinetic behavior

Quantitative analysis of T-wave morphology increases confidence in drug-induced cardiac repolarization abnormalities: evidence from the investigational IKr inhibitor Lu 35-138

DEFF Research Database (Denmark)

Graff, Claus; Matz, Jørgen; Christensen, Ellen B

2009-01-01

prolongation. Seventy-nine healthy subjects were included in this parallel study. After a baseline day during which no drug was given, 40 subjects received an I(Kr)-blocking antipsychotic compound (Lu 35-138) on 7 consecutive days while 39 subjects received placebo. Resting ECGs were recorded and used...... to determine a combined measure of repolarization morphology (morphology combination score [MCS]), based on asymmetry, flatness, and notching. Replicate measurements were used to determine reliable change and study power for both measures. Lu 35-138 increased the QTc interval with corresponding changes in T......-wave morphology as determined by MCS. For subjects taking Lu 35-138, T-wave morphology was a more reliable indicator of I(Kr) inhibition than QTcF (chi(2) = 20.3, P = .001). At 80% study power for identifying a 5-millisecond placebo-adjusted change from baseline for QTcF, the corresponding study power for MCS...

Crystal growth, spectroscopic and laser properties of Tm:LuAG crystal

Science.gov (United States)

Xu, X. D.; Wang, X. D.; Lin, Z. F.; Cheng, Y.; Li, D. Z.; Cheng, S. S.; Wu, F.; Zhao, Z. W.; Gao, C. Q.; Gao, M. W.; Xu, J.

2009-11-01

Tm:Lu3Al5O12 (Tm:LuAG) crystal was grown by the Czochralski method. The segregation coefficient was measured by Inductively Coupled Plasma Atomic Emission Spectrometer. The cell parameters were analyzed with X-ray powder diffraction experiments. The absorption and fluorescence spectra of Tm:LuAG crystal at room temperature were investigated. With a 20 W fiber-coupled diode laser as pump source, the continuous-wave (CW) laser action of Tm:LuAG crystal was demonstrated. The maximum output power at 2020 nm was obtained to be 3.04 W, and the slope efficiency was 25.3%.

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

Science.gov (United States)

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

2018-02-01

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

Synthesis and upconversion luminescence properties of YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers derived from Y{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers

Energy Technology Data Exchange (ETDEWEB)

Li Dan; Dong Xiangting, E-mail: dongxiangting888@163.com; Yu Wensheng; Wang Jinxian; Liu Guixia [Changchun University of Science and Technology, Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province (China)

2013-06-15

YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers were successfully fabricated via fluorination of the relevant Y{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers which were obtained by calcining the electrospun PVP/[Y(NO{sub 3}){sub 3} + Yb(NO{sub 3}){sub 3} + Er(NO{sub 3}){sub 3}] composite nanofibers. The morphology and properties of the products were investigated in detail by X-ray diffraction, scanning electron microscope, transmission electron microscope, and fluorescence spectrometer. YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers were pure orthorhombic phase with space group Pnma and were hollow-centered structure with mean diameter of 174 {+-} 22 nm, and YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers are composed of nanoparticles with size in the range of 30-60 nm. Upconversion emission spectrum analysis manifested that YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers emitted strong green and weak red upconversion emissions centering at 523, 545, and 654 nm, respectively. The green and red emissions were, respectively, originated from {sup 2}H{sub 11/2}/{sup 4}S{sub 3/2} {yields} {sup 4}I{sub 15/2} and {sup 4}F{sub 9/2} {yields} {sup 4}I{sub l5/2} energy levels transitions of the Er{sup 3+} ions. Moreover, the emitting colors of YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers were located in the green region in CIE chromaticity coordinates diagram. This preparation technique could be applied to prepare other rare earth fluoride upconversion luminescence hollow nanofibers.Graphical AbstractYF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers with orthorhombic structure were synthesized by fluorination of the electrospun Y{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers via a double-crucible method using NH{sub 4}HF{sub 2} as fluorinating agent. The mean diameter of YF{sub 3}:Yb{sup 3+}/Er{sup 3+} hollow nanofibers was 174 {+-} 22 nm. The fluorination method we proposed here has been proved to be an important method, as it can not only

Instrumental neutron activation analysis of rocks from Cayajabos petroleum ore

International Nuclear Information System (INIS)

Montero Cabrera, M.E.; Herrera Hernandez, H.; Herrera Peraza, E.; Rodriguez Martinez, N.; Lopez Reyes, M.C.

2000-01-01

The relative INAA method under statistical control was used to measure the concentrations of Sb, La, Eu, Co, Rb, Tb, Cs, Hf, Th, Cr, Lu, Yb, Ce, Sm, Gd, Nd. Rare earth element (REE) Chondrite-normalized patterns are presented. The La cond /Lu cond normalized concentration ratios obtained confirm the carbonaceous character of the rocks

Regularity in the formation of compounds in ternary R-Me-Sn systems, R - REM, Me - Fe, Co, Ni, Cu

International Nuclear Information System (INIS)

Skolozdra, R.V.; Komarovskaya, L.P.; Koretskaya, O.Eh.

1992-01-01

For the ternary alloy systems of (La, Y, Gd, Lu)-Fe-Sn, (Ce, Y, Gd)-Co-Sn, (Ce, Y, Gd, Lu)-Ni-Sn and (Pr, Gd, Lu)-Cu-Sn isothermal sections of phase diagrams were plotted within the range of 670 to 870 K. It was revealed that substitution of transition metal in the kFe-Co-Ni-Cu series led to changes both in a number of ternary stannides and their structural types. A tendency was observed in change of stannide numbers depending on quantity ratio of R and Me components. Crystallochemical analysis of compounds obtained showed that they could be treated as interstitial structures or lsuperstructures with respect to them. The results of magnetic properties measurements were used for explanation of structural features of ternary compounds considered

Synthesis of main group, rare-earth, and d{sup 0} metal complexes containing beta-hydrogen

Energy Technology Data Exchange (ETDEWEB)

Yan, Ka King [Iowa State Univ., Ames, IA (United States)

2013-01-01

A series of organometallic compounds containing the tris(dimethylsilyl)methyl ligand are described. The potassium carbanions KC(SiHMe₂)₃ and KC(SiHMe₂})₃TMEDA are synthesized by deprotonation of the hydrocarbon HC(SiHMe₂)₃ with potassium benzyl. KC(SiHMe₂)₃TMEDA crystallizes as a dimer with two types of three-center-two-electron KH- Si interactions. Homoleptic Ln(III) tris(silylalkyl) complexes containing β-SiH groups M{C(SiHMe₂)₃}₃ (Ln = Y, Lu, La) are synthesized from salt elimination of the corresponding lanthanide halide and 3 equiv. of KC(SiHMe₂)₃. The related reactions with Sc yield bis(silylalkyl) ate-complexes containing either LiCl or KCl. The divalent calcium and ytterbium compounds M{C(SiHMe₂)₃}₂L (M = Ca, Yb; L = THF₂ or TMEDA) are prepared from MI₂ and 2 equiv of KC(SiHMe₂)₃. The compounds M{C(SiHMe₂)₃}₂L (M = Ca, Yb; L = THF₂ or TMEDA) and La{C(SiHMe₂)₃}₃ react with 1 equiv of B(C₆F₅)₃ to give 1,3- disilacyclobutane {Me2Si-C(SiHMe2)2}2 and MC(SiHMe2)3HB(C6F5)3L, and La{C(SiHMe₂)₃}₂HB(C₆F₅)₃, respectively. The corresponding reactions of Ln{C(SiHMe₂)₃}₃ (Ln = Y, Lu) give the β-SiH abstraction product [{(Me₂HSi)₃C}₂LnC(SiHMe₂)₂SiMe₂][HB(C₆F₅)₃] (Ln = Y, Lu), but the silene remains associated with the Y or Lu center. The abstraction reactions of M{C(SiHMe₂)₃}₂L (M = Ca, Yb; L = THF₂or TMEDA) and Ln{C(SiHMe₂)₃}₃ (Ln = Y, Lu, La) and 2 equiv of B(C₆

Lu{sub 2}O{sub 3}:Tb,Hf storage phosphor

Energy Technology Data Exchange (ETDEWEB)

Kulesza, Dagmara; Trojan-Piegza, Joanna [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zych, Eugeniusz, E-mail: zych@wchuwr.p [Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie Street, 50-383 Wroclaw (Poland)

2010-03-15

Lu{sub 2}O{sub 3}:Tb,Hf ceramics containing 0.1% of Tb and 0-1.5% of Hf were prepared in reducing atmosphere at 1700 {sup o}C and their thermoluminescence properties were systematically studied. For comparison Tb,Ca co-doped specimen was also fabricated and investigated. The Tb,Hf ceramics shows basically a single TL band located around 180 {sup o}C as found with heating rate of 15 {sup o}C/min. Ceramics singly doped with Tb show complex TL glow curves indicating the presence of traps of very different depths. On the other hand Tb,Ca co-doping is beneficial for the development of shallow traps with the main TL band around 70 {sup o}C. Hence, the aliovalent impurities, Ca{sup 2+} and Hf{sup 4+}, strongly influenced the traps structure in Lu{sub 2}O{sub 3}:Tb ceramics, each of them in its own specific way. Isothermal decay of Lu{sub 2}O{sub 3}:Tb,Hf at 185 {sup o}C was recorded and its shape suggest that multiple hole trapping occurs in the Lu{sub 2}O{sub 3}:Tb,Hf ceramics. Due to the different traps depths the Lu{sub 2}O{sub 3}:Tb,Hf ceramics possess properties typical for storage phosphors, while Lu{sub 2}O{sub 3}:Tb,Ca is a persistent luminescent material rather.

'Obligate' anaerobic Salmonella strain YB1 suppresses liver tumor growth and metastasis in nude mice.

Science.gov (United States)

Li, Chang-Xian; Yu, Bin; Shi, Lei; Geng, Wei; Lin, Qiu-Bin; Ling, Chang-Chun; Yang, Mei; Ng, Kevin T P; Huang, Jian-Dong; Man, Kwan

2017-01-01

The antitumor properties of bacteria have been demonstrated over the past decades. However, the efficacy is limited and unclear. Furthermore, systemic infection remains a serious concern in bacteria treatment. In this study, the effect of YB1, a rationally designed 'obligate' anaerobic Salmonella typhimurium strain, on liver tumor growth and metastasis in a nude mouse orthotopic liver tumor model was investigated. The orthotopic liver tumor model was established in nude mice using the hepatocellular carcinoma cell line MHCC-97L. Two weeks after orthotopic liver tumor implantation, YB1, SL7207 and saline were respectively administered through the tail vein of the mice. Longitudinal monitoring of tumor growth and metastasis was performed using Xenogen IVIS, and direct measurements of tumor volume were taken 3 weeks after treatment. In vitro , MHCC-97L and PLC cells were incubated with YB1 or SL7207 under anaerobic conditions. YB1 was observed to invade tumor cells and induce tumor cell apoptosis and death. The results revealed that all mice in the YB1 group were alive 3 weeks after YB1 injection while all mice in the SL7207 group died within 11 days of the SL7207 injection. The body weight decreased by ~9% on day 1 after YB1 injection and but subsequently recovered. Liver tumor growth and metastases were significantly inhibited following YB1 treatment. By contrast to the control group, a large number of Gr1-positive cells were detected on days 1 to 21 following YB1 treatment. Furthermore, YB1 also effectively invaded tumor cells and induced tumor cell apoptosis and death. In conclusion, YB1 suppressed liver tumor growth and metastasis in a nude mice liver tumor model. The potential mechanism may be through enhancing innate immune response and inducing tumor cell apoptosis and cell death.

Optical spectroscopy and luminescence quenching of LuI3:Ce3+

International Nuclear Information System (INIS)

Birowosuto, M.D.; Dorenbos, P.; Haas, J.T.M. de; Eijk, C.W.E. van; Kraemer, K.W.; Guedel, H.U.

2006-01-01

Optical spectroscopy of LuI 3 doped with Ce 3+ using ultraviolet and visible light excitation is reported. LuI 3 host excitation and emission and 4f-5d excitation and emission of Ce 3+ are observed. An empirical model based on crystal field splitting was used to estimate the energy of the highest 4f-5d excitation band. The crystal field splitting and centroid shift were compared to those of LuCl 3 :Ce 3+ and LuBr 3 :Ce 3+ . Temperature dependence of X-ray excited luminescence spectra shows thermal quenching, whereas that of the decay curve of Ce 3+ emission excited at the lowest 5d band of Ce 3+ does not indicate the presence of quenching of Ce 3+ emission for temperature below 625K. The quenching in LuI 3 :Ce 3+ therefore occurs before the 5d Ce 3+ emission takes place

Comparative study on DOTA-derivatized bombesin analog labeled with 90Y and 177Lu: in vitro and in vivo evaluation

International Nuclear Information System (INIS)

Koumarianou, Eftychia; Mikolajczak, Renata; Pawlak, Dariusz; Zikos, Xhristos; Bouziotis, Pinelopi; Garnuszek, Piotr; Karczmarczyk, Urszula; Maurin, Michal; Archimandritis, Spyridon C.

2009-01-01

Introduction: The aim of the study was to compare in vitro and in vivo a novel DOTA-chelated bombesin (BN) analog of the amino acid sequence, QRLGNQWAVGHLM-CONH 2 (BN[2-14]NH 2 ), labeled with 90 Y and 177 Lu, for its potential use in targeted radiotherapy of tumors expressing gastrin releasing peptide (GRP) receptors. The same amino acid sequence, but with different chelator, referred as BN1.1 (Gly-Gly-Cys-Aca-QRLGNQWAVGHLM-CONH 2 ), has already been studied and reported; however, the DOTA-chelated one, suitable for labeling with M +3 type radiometals, was not yet described. Methods: The conditions for labeling of DOTA-BN[2-14]NH 2 with noncarrier added 90 Y and with 177 Lu [specific activity (SA), 15 Ci/mg Lu] were investigated and optimized to provide 90 Y-DOTA-BN[2-14]NH 2 and 177 Lu-DOTA-BN[2-14]NH 2 of high SA. The stability of the radiolabeled compounds in human serum was evaluated over a period of 24 h. The human prostate cancer cell line PC-3, known to express GRP receptors, was used for in vitro evaluation of radiolabeled peptide affinity to GRP receptors and for assessment of cytotoxicity of both nonlabeled and radiolabeled peptide. Biodistribution accompanied by receptor blocking was studied in normal Swiss mice. Results: 90 Y-DOTA-BN[2-14]NH 2 and 177 Lu-DOTA-BN[2-14]NH 2 were obtained with radiochemical yield >98% and high SA (67.3 GBq 90 Y/μmol and 33.6 GBq 177 Lu/μmol, respectively). They were stable when incubated in human serum for up to 24 h. The binding affinities of DOTA-BN[2-14]NH 2 and both nat Y- and nat Lu-labeled analogs to GRP receptors were high (IC 50 =1.78, 1.99, and 1.34 nM, respectively), especially for the nat Lu-DOTA-BN[2-14]NH 2 complex. The cytotoxicity study of DOTA-BN[2-14]NH 2 to PC-3 cells revealed an IC 50 =6300 nM after 72 h of exposition, while the labeled derivatives showed no significant cytotoxic effect. The internalization rate to PC-3 cells was more rapid for 177 Lu-labeled peptide (84.87%) than for the 90 Y

Crystal growth, spectral and laser properties of Nd:LuAG single crystal

International Nuclear Information System (INIS)

Xu, X D; Meng, J Q; Cheng, Y; Li, D Z; Cheng, S S; Wu, F; Zhao, Z W; Wang, X D; Xu, J

2009-01-01

Nd:LuAG (Nd:Lu 3 Al 5 O 12 ) crystal was grown by the Czochralski method. X-ray powder diffraction experiments show that the Nd:LuAG crystal crystallizes in the cubic with space group Ia3d and has the cell parameter: a = 1.1907 nm, V = 1.6882 nm 3 . The absorption and fluorescence spectra of Nd:LuAG crystal at room temperature were investigated. With a fiber-coupled diode laser as pump source, the continuous-wave (CW) laser action of Nd:LuAG crystal was demonstrated. The maximum output power at 1064 nm was obtained to be 3.8 W under the incident pump power of 17.3 W, with the optical conversion efficiency 22.0% and the slope efficiency 25.7%

Crystal growth, spectral and laser properties of Nd:LuAG single crystal

Science.gov (United States)

Xu, X. D.; Wang, X. D.; Meng, J. Q.; Cheng, Y.; Li, D. Z.; Cheng, S. S.; Wu, F.; Zhao, Z. W.; Xu, J.

2009-09-01

Nd:LuAG (Nd:Lu3Al5O12) crystal was grown by the Czochralski method. X-ray powder diffraction experiments show that the Nd:LuAG crystal crystallizes in the cubic with space group Ia3d and has the cell parameter: a = 1.1907 nm, V = 1.6882 nm3. The absorption and fluorescence spectra of Nd:LuAG crystal at room temperature were investigated. With a fiber-coupled diode laser as pump source, the continuous-wave (CW) laser action of Nd:LuAG crystal was demonstrated. The maximum output power at 1064 nm was obtained to be 3.8 W under the incident pump power of 17.3 W, with the optical conversion efficiency 22.0% and the slope efficiency 25.7%.

Facile synthesis of NaYF4:Yb, Ln/NaYF4:Yb core/shell upconversion nanoparticles via successive ion layer adsorption and one-pot reaction technique

NARCIS (Netherlands)

Zeng, Q.; Xue, B.; Zhang, Y.; Wang, D.; Liu, X.; Tu, L.; Zhao, H.; Kong, X.; Zhang, H.

2013-01-01

The facile one-pot synthesis of NaYF4:Yb, Ln/NaYF4:Yb core/shell (CS) upconversion nanoparticles (UCNPs) was firstly developed through the successive ion layer adsorption and reaction (SILAR) technique, which represents an attractive alternative to conventional synthesis utilizing the chloride of Ln

The complexity of the CaF2:Yb system: evidence that CaF2:Yb2+ is not an impurity trapped exciton system

Science.gov (United States)

Mackeen, Cameron; Bridges, Frank; Kozina, Michael; Mehta, Apurva; Reid, M. F.; Wells, J.-P. R.; BarandiaráN, Zoila

Fluorite crystal structures doped with rare-earth elements exhibit an anomalous redshifted luminescence upon UV excitation, generally attributed to the relaxation of impurity trapped excitons (ITE). We find that the intensity of this luminescence decreases as the total concentration of Yb 2+ increases in unexposed samples, which is in conflict with the currently accepted ITE model. Further, using x-ray absorption spectroscopy and UV-vis studies of CaF2:Yb, we find a large (but reversible) Yb valence reduction upon x-ray exposure at 200 K - from mostly 3+ to 2+. This valence reduction is stable for long time periods at low T ITE model; the data appear more consistent with an intervalence charge transfer (IVCT) model. It is likely that many similar ITE systems have also been misidentified.

Neutron-induced capture cross sections via the surrogate reaction method

International Nuclear Information System (INIS)

Boutoux, G.; Jurado, B.; Aiche, M.; Barreau, G.; Capellan, N.; Companis, I.; Czajkowski, S.; Dassie, D.; Haas, B.; Mathieu, L.; Meot, V.; Bail, A.; Bauge, E.; Daugas, J. M.; Faul, T.; Gaudefroy, L.; Morel, P.; Pillet, N.; Roig, O.; Romain, P.; Taieb, J.; Theroine, C.; Burke, J.T.; Companis, I.; Derkx, X.; Gunsing, F.; Matea, I.; Tassan-Got, L.; Porquet, M.G.; Serot, O.

2011-01-01

The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This technique enables neutron-induced cross sections to be extracted for nuclear reactions on short-lived unstable nuclei that otherwise can not be measured. This technique has been successfully applied to determine the neutron-induced fission cross sections of several short-lived nuclei. In this work, we investigate whether this powerful technique can also be used to determine of neutron-induced capture cross sections. For this purpose we use the surrogate reaction 174 Yb( 3 He, pγ) 176 Lu to infer the well known 175 Lu(n, γ) cross section and compare the results with the directly measured neutron-induced data. This surrogate experiment has been performed in March 2010. The experimental technique used and the first preliminary results will be presented. (authors)

Microscopic analysis of shape transition in neutron-deficient Yb isotopes

Science.gov (United States)

Fu, Y.; Tong, H.; Wang, X. F.; Wang, H.; Wang, D. Q.; Wang, X. Y.; Yao, J. M.

2018-01-01

The development of nuclear collectivity in even-even Yb-170152 is studied with three types of mean-field calculations: the nonrelativistic Hartree-Fock plus BCS calculation using the Skyrme SLy4 force plus a density-dependent δ pairing force and the relativistic mean-field calculation using a point-coupling energy functional supplemented with either a density-independent δ pairing force or a separable pairing force. The low-lying states are obtained by solving a five-dimensional collective Hamiltonian with parameters determined from the three mean-field solutions. The energy surfaces, excitation energies, electric multiple transition strengths, and differential isotope shifts are presented in comparison with available data. Our results show that different treatments of pairing correlations have a significant influence on the speed of developing collectivity as the increase of neutron number. All the calculations demonstrate the important role of dynamic shape-mixing effects in resolving the puzzle in the dramatic increase of charge radius from 152Yb to 154Yb and the role of triaxiality in Yb 160 ,162 ,164 .

Incorporation of Pr into LuAG ceramics

Science.gov (United States)

Marchewka, M. R.; Chapman, M. G.; Qian, H.; Jacobsohn, L. G.

2017-06-01

An investigation of the effects of Pr in (Lu1-xPrx)3Al5O12 (LuAG:Pr) ceramics was carried out by means of x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), and attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR) measurements coupled with luminescence measurements. It was found that the Pr concentration that maximizes luminescence emission depends on the thermal processing conditions. While the calcined LuAG:Pr powder showed maximum luminescence emission for Pr concentrations between 0.18 and 0.33 at.%, maximum emission of ceramic bodies sintered at 1500 °C for 20 h was obtained with Pr concentrations between 0.018 and 0.18 at.%. Further, for short sintering times up to about 3 h, luminescence emission intensity is maximum for Pr concentrations around 0.33 at.%. Longer sintering times lead to the formation of PrAlO3 as a secondary phase, concomitant with a reduction of the intensity of luminescence emission.

Multispecies animal investigation on biodistribution, pharmacokinetics and toxicity of {sup 177}Lu-EDTMP, a potential bone pain palliation agent

Energy Technology Data Exchange (ETDEWEB)

Mathe, Domokos [Department of Applied Radioisotopes and Animal Experimentation, National ' Frederic Joliot-Curie' Institute of Radiobiology and Radiohygiene, H-1221 Budapest (Hungary)], E-mail: mdomokos@hp.osski.hu; Balogh, Lajos; Polyak, Andras; Kiraly, Reka [Department of Applied Radioisotopes and Animal Experimentation, National ' Frederic Joliot-Curie' Institute of Radiobiology and Radiohygiene, H-1221 Budapest (Hungary); Marian, Terez [Institute of Nuclear Medicine, Debrecen University, Debrecen (Hungary); Pawlak, Dariusz [Institute of Atomic Energy, Radioisotope Centre POLATOM, Swierk-Otwock (Poland); Zaknun, John J.; Pillai, Maroor R.A. [International Atomic Energy Agency (IAEA), Vienna (Austria); Janoki, Gyozo A. [Department of Applied Radioisotopes and Animal Experimentation, National ' Frederic Joliot-Curie' Institute of Radiobiology and Radiohygiene, H-1221 Budapest (Hungary)

2010-02-15

Introduction: Radionuclide therapy (RNT) is an effective method for bone pain palliation in patients suffering from bone metastasis. Due to the long half-life, easy production and relatively low {beta}- energy, {sup 177}Lu [T{sub 1/2}=6.73 days, E{sub {beta}}{sub max}=497 keV, E{sub {gamma}}=113 keV (6.4%), 208 keV (11%)]-based radiopharmaceuticals offer logistical advantage for wider use. This paper reports the results of a multispecies biodistribution and toxicity studies of {sup 177}Lu-EDTMP to collect preclinical data for starting human clinical trials. Methods: {sup 177}Lu-EDTMP with radiochemical purity greater than 99% was formulated by using a lyophilized kit of EDTMP (35 mg of EDTMP, 5.72 g of CaO and 14.1 mg of NaOH). Biodistribution studies were conducted in mice and rabbits. Small animal imaging was performed using NanoSPECT/CT (Mediso, Ltd., Hungary) and digital autoradiography. Gamma camera imaging was done in rabbits and dogs. Four levels of activity (9.25 through 37 MBq/kg body weight) of {sup 177}Lu-EDTMP were injected in four groups of three dogs each to study the toxicological effects. Results: {sup 177}Lu-EDTMP accumulated almost exclusively in the skeletal system (peak ca. 41% of the injected activity in bone with terminal elimination half-life of 2130 and 1870 h in mice and rabbits, respectively) with a peak uptake during 1-3 h. Excretion of the radiopharmaceutical was through the urinary system. Imaging studies showed that all species (mouse, rat, rabbit and dog) take up the compound in regions of remodeling bone, while kidney retention is not visible after 1 day postinjection (pi). In dogs, the highest applied activity (37 MBq/kg body weight) led to a moderate decrease in platelet concentration (mean, 160 g/L) at 1 week pi with no toxicity. Conclusion: The protracted effective half-life of {sup 177}Lu-EDTMP in bone supports that modifying the EDTMP molecule by introducing {sup 177}Lu does not alter its biological behaviour as a specific bone

Spectroscopic properties and energy levels of Yb{sup 3+} ion in huntite structure

Energy Technology Data Exchange (ETDEWEB)

Malakhovskii, A.V. [L.V. Kirensky Institute of Physics, Siberian Branch Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation)], E-mail: malakha@iph.krasn.ru; Sukhachev, A.L. [L.V. Kirensky Institute of Physics, Siberian Branch Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation); Gnatchenko, S.L.; Kachur, I.S.; Piryatinskaya, V.G. [B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 61103 Kharkov (Ukraine); Temerov, V.L.; Krylov, A.S.; Edelman, I.S. [L.V. Kirensky Institute of Physics, Siberian Branch Russian Academy of Sciences, 660036 Krasnoyarsk (Russian Federation)

2009-05-12

Temperature dependence of Yb{sup 3+} optical absorption spectrum has been studied in crystals Yb{sub x}Tm{sub 1-x}Al{sub 3}(BO{sub 3}){sub 4} (x = 0.1, 0.2 and 1) in the temperature range 1.7-293 K. The spectra of the crystals appeared to be practically identical for the studied ytterbium concentrations. Raman scattering spectrum of YbAl{sub 3}(BO{sub 3}){sub 4} crystal has been measured. Group theory analysis of the optical absorption spectra is made, and new energy structure of the ground and excited states of Yb{sup 3+} ion, based on the experimental data obtained, is presented. Transformation of the local environment of Yb{sup 3+} ion depending on temperature has been found out. Spectrum of luminescence has been calculated from the absorption spectrum by reciprocity method with the use of the proposed energy structure.

Investigations on Ce- and Yb-based intermetallic compounds

International Nuclear Information System (INIS)

Elenbaas, R.A.

1980-01-01

The author describes investigations on a number of cerium- and ytterbium-based intermetallic compounds and alloys, yielding a lot of experimental results which could not always be put in a quantitative picture. All experimental data are consistent with a single-ion behaviour, where the 4f state is more or less modified by the conduction electrons. In the investigated systems several different features of the magnetism of cerium atoms in metals were studied. (Auth.)

LuIII parvovirus selectively and efficiently targets, replicates in, and kills human glioma cells.

Science.gov (United States)

Paglino, Justin C; Ozduman, Koray; van den Pol, Anthony N

2012-07-01

Because productive infection by parvoviruses requires cell division and is enhanced by oncogenic transformation, some parvoviruses may have potential utility in killing cancer cells. To identify the parvovirus(es) with the optimal oncolytic effect against human glioblastomas, we screened 12 parvoviruses at a high multiplicity of infection (MOI). MVMi, MVMc, MVM-G17, tumor virus X (TVX), canine parvovirus (CPV), porcine parvovirus (PPV), rat parvovirus 1A (RPV1A), and H-3 were relatively ineffective. The four viruses with the greatest oncolytic activity, LuIII, H-1, MVMp, and MVM-G52, were tested for the ability, at a low MOI, to progressively infect the culture over time, causing cell death at a rate higher than that of cell proliferation. LuIII alone was effective in all five human glioblastomas tested. H-1 progressively infected only two of five; MVMp and MVM-G52 were ineffective in all five. To investigate the underlying mechanism of LuIII's phenotype, we used recombinant parvoviruses with the LuIII capsid replacing the MVMp capsid or with molecular alteration of the P4 promoter. The LuIII capsid enhanced efficient replication and oncolysis in MO59J gliomas cells; other gliomas tested required the entire LuIII genome to exhibit enhanced infection. LuIII selectively infected glioma cells over normal glial cells in vitro. In mouse models, human glioblastoma xenografts were selectively infected by LuIII when administered intratumorally; LuIII reduced tumor growth by 75%. LuIII also had the capacity to selectively infect subcutaneous or intracranial gliomas after intravenous inoculation. Intravenous or intracranial LuIII caused no adverse effects. Intracranial LuIII caused no infection of mature mouse neurons or glia in vivo but showed a modest infection of developing neurons.

Whole-body retention studies of /sup 169/Yb-citrate. Estimation of radiation dose to humans from /sup 169/Yb-citrate

Energy Technology Data Exchange (ETDEWEB)

Ando, A; Hiraki, T [Kanazawa Univ. (Japan). School of Paramedicine; Mori, H; Ando, I; Hisada, K

1977-09-01

For purpose of the estimation of the radiation dose to humans from /sup 169/Yb-citrate, the whole-body retention studies using five rats were carried out. Following intravenous administration of /sup 169/Yb-citrate, the whole-body activity was monitored for 40 days by the animal counter. The whole-body retention curve consisted of three components: the first with a 3.6 hours effective half-time, the second with an 154 hours effective half-time and the third with a 29.9 days effective half-time. Therefore it was assumed that 32% of the administered /sup 169/Yb-citrate clears from the kidney with a short biologic half-time (3.6 hours), 18% remains in the liver and other soft tissues with a relatively long biologic half-time (194 hours) and 50% remains in the bone with a long biologic half-time (850 days). Based on these biological data and the MIRD Committee method, the average dose to the bone and whole-body were 20.8 rads/mCi and 4.5 rads/mCi respectively.

Photoluminescence characterization of porous YAG: Yb{sup 3+}–Er{sup 3+} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Desirena, H., E-mail: hagdes@cio.mx [Centro de Investigaciones en Óptica, A. P. 1-948, León 37150, Guanajuato (Mexico); Diaz-Torres, L.A. [Centro de Investigaciones en Óptica, A. P. 1-948, León 37150, Guanajuato (Mexico); Rodríguez, R.A. [Centro Universitario de Los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco (Mexico); Meza, O. [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Centro Historico 72570, Puebla (Mexico); Salas, P. [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Apartado Postal 1-1010, Querétaro 76000, Querétaro México (Mexico); Angeles-Chávez, C. [Instituto Mexicano del Petróleo, Ciudad México, D.F. 07730, México (Mexico); Tobar, E.H.; Castañeda-Contreras, J. [Centro Universitario de Los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Óptica, A. P. 1-948, León 37150, Guanajuato (Mexico)

2014-09-15

Yb{sup 3+}/Er{sup 3+} codoped yttrium aluminium garnet (YAG) porous nanocrystals were prepared by glycolate method assisted with poly-vinyl alcohol (PVA) and urea. The typical cubic structure for YAG was confirmed from XRD with crystallite average size of ∼40 nm, calculated from Scherrer formula and corroborated by TEM. Strong green and red upconversion emissions are observed readily with the naked eyes, and the color coordinates were obtained from emission spectra. A theoretical model to calculate CIE coordinate as a function of donor (Yb{sup 3+}) and acceptors (Er{sup 3+}) concentration is proposed. The eye-safe near infrared emitted signal and fluorescence lifetime were also measured and results show lifetime as large as 8.5 ms. The maximum energy transfer efficiency from Yb{sup 3+} to Er{sup 3+} was 72% for 20 mol% of Yb{sub 2}O{sub 3}. The proposed mechanisms for signal emitted are explained in terms of direct and energy back transfer processes, and cross relaxation. - Highlights: • Strong upconversion emission were observed in YAG:Er{sup 3+}–Yb{sup 3+} samples. • Color emission can be tuned from green to red by choosing properly the Yb{sup 3+} concentration. • The experimental colour coordinates match very well with the proposed theoretical model. • Cross relaxation and energy back transfer are mainly responsible for the red emission. • Fluorescence lifetime of {sup 4}I{sub 13/2} level increase with the Yb{sup 3+} concentration.

Structural specifics of the condensate prepared by thermal evaporation of alloys of As2S3-Yb systems

International Nuclear Information System (INIS)

Ehfendiev, Eh.G.; Mamedov, A.I.; Il'yasov, T.M.; Rustamov, P.G.

1987-01-01

The problem aimed at preparation of the films of As 2 S 3 -Yb system, at studying their substructure depending on condensation conditions and defining noncrystallinity region of this system in the film state, is formulated. It is shown that in representative samples of As 2 S 3 -Yb system the vitrification region is extended up to 7 at.% Yb, in the films noncrystallinity region is extended up to 30 at.% Yb. With up to 30 at.% increase of ytterbium amount in initial alloys a tendency to crystallization in amorphous condensate structure is noticed. In evaporation of As 2 S 3 + 40 at.% Yb and As 2 S 3 + 50 at.% Yb, unknown in the film state YbAs 2 S 4 , Yb 3 As 4 S 9 and YbAs 4 S 7 phases are prepared, and the latter is formed in case of As 2 S 3 + 50 at.% Yb alloy at small evaporation rates (∼10 A/s). Substructure of As 2 S 3 + 50 at.% Yb alloy prepared condensate is more dependent on evaporation rate than in evaporation of As 2 S 3 + 40 at.% Yb alloy. In this case, evaporation rates being ∼ 100 A/s, the condensate has a polycrystal structure, and at small rates of ∼ 10 A/c, condensate structure is primarily blocked

First observation of yrast band in odd-odd 162Lu

International Nuclear Information System (INIS)

Zhang, Y.H.; Yuan, G.J.; Liu, X.A.

1996-01-01

High spin states of the odd-odd 162 Lu nucleus have been studied via 147 Sm( 19 F, 4nγ) 162 Lu reaction at 95MeV beam energy. Level scheme for yrast band based on π[h 11/2 ] υ[i 13/2 ] quasiparticle configuration was established up to I π =(23 - ) for the first time. This band shows the signature inversion in energy before backbending generally appeared in this mass region. It is stressed that the signature splitting in 162 Lu is larger than that in the 160 Tm nucleus. (orig.)

Rare earth-rich cadmium compounds RE{sub 10}TCd{sub 3} (RE = Y, Tb, Dy, Ho, Er, Tm, Lu; T = Rh, Pd, Ir, Pt) with an ordered Co{sub 2}Al{sub 5}-type structure

Energy Technology Data Exchange (ETDEWEB)

Block, Theresa; Klenner, Steffen; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2018-04-01

Eighteen new rare earth-rich intermetallic phases RE{sub 10}TCd{sub 3} (RE = Y, Tb, Dy, Ho, Er, Tm, Lu; T = Rh, Pd, Ir, Pt) were obtained by induction melting of the elements in sealed niobium ampoules followed by annealing in muffle furnaces. All samples were characterized by X-ray powder diffraction. The structures of four representatives were refined from single-crystal X-ray diffractometer data: ordered Co{sub 2}Al{sub 5} type, P6{sub 3}/mmc, a = 951.2(1), c = 962.9(2) pm, wR = 0.0460, 595 F{sup 2} values, 20 parameters for Er{sub 10}RhCd{sub 3}; a = 945.17(4), c = 943.33(4), wR = 0.0395, 582 F{sup 2} values, 21 parameters for Lu{sub 9.89}PdCd{sub 3.11}; a = 964.16(6), c = 974.93(6) pm, wR = 0.0463, 614 F{sup 2} values, 21 parameters for Y{sub 10}Ir{sub 1.09}Cd{sub 2.91}; a = 955.33(3), c = 974.56(3) pm, wR = 0.0508, 607 F{sup 2} values, 22 refined parameters for Dy{sub 9.92}IrCd{sub 3.08}. Refinements of the occupancy parameters revealed small homogeneity ranges resulting from RE/Cd, respectively T/Cd mixing. The basic building units of the RE{sub 10}TCd{sub 3} phases are transition metal-centered RE{sub 6} trigonal prisms (TP) that are condensed with double-pairs of empty RE{sub 6} octahedra via common triangular faces. A second type of rods is formed by slightly distorted RE3 rate at Cd{sub 6}RE{sub 6} icosahedra which are condensed via Cd{sub 3} triangular faces. The shortest interatomic distances occur for RE-T, compatible with strong covalent bonding interactions. Temperature dependent magnetic susceptibility measurements were performed for RE{sub 10}RhCd{sub 3} (RE = Dy-Tm, Lu), RE{sub 10}IrCd{sub 3} (RE = Er, Tm, Lu) and RE{sub 10}PtCd{sub 3} (RE = Y, Lu). While Y{sub 10}PtCd{sub 3} and Lu{sub 10}TCd{sub 3} (T = Rh, Ir, Pt) show Pauli paramagnetic behavior, the compounds containing paramagnetic rare earth elements show Curie-Weiss behavior (the experimental magnetic moments indicate stable trivalent RE{sup 3+}) and magnetic ordering at low temperatures

The RMgSn{sub 2} series of compounds (R = rare earth metal). Synthesis, crystal structure, and magnetic measurements

Energy Technology Data Exchange (ETDEWEB)

Solokha, Pavlo; Minetti, Riccardo; De Negri, Serena; Saccone, Adriana [Dipartimento di Chimica e Chimica Industriale, Universita di Genova (Italy); Pereira, Laura Cristina J.; Goncalves, Antonio P. [Centro de Ciencias e Tecnologias Nucleares, Instituto Superior Tecnico, EN 10, Universidade de Lisboa, Bobadela (Portugal)

2017-06-30

The novel isostructural series of phases RMgSn{sub 2} (R = Y, La-Nd, Sm, Gd-Tm, Lu) is presented. They were prepared by direct synthesis in an induction furnace and subsequently annealed at 500 C. Their crystal structures were determined through single-crystal X-ray diffraction analysis of the Ce representative [I anti 42m, tI32-LaMgSn{sub 2}, Z = 8, a = 0.82863(3) nm, c = 1.23129(5) nm] and confirmed by powder X-ray diffraction analysis of the other members of the series. Rietveld refinements were also performed on the homologues with R = Pr, Tm, and Y. The title phases show a unique space distribution of atoms, characterized by the presence of a Sn-Sn dumbbell distanced at around 0.29 nm. Their structures are related to those of a few binary AeTt{sub 3} (Ae = alkaline earth; Tt = Si, Ge; I4/mmm, tI32-YbSi{sub 3}) compounds that are stable at high pressure, characterized by a more complex 3D covalently bonded Tt network. Compounds CeMgSn{sub 2} and TbMgSn{sub 2} were magnetically characterized; they show paramagnetic behavior with the presence of ferromagnetic interactions, more pronounced in the case of TbMgSn{sub 2}, as suggested by the Curie-Weiss temperatures, determined in the high-temperature range, of 0.96 and 27.6 K for CeMgSn{sub 2} and TbMgSn{sub 2}, respectively. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Mälu sildistamine / Erkki Bahovski

Index Scriptorium Estoniae

Bahovski, Erkki, 1970-

2007-01-01

President Toomas Hendrik Ilvese üleskutsest moodustada Mälu Instituut Eesti lähimineviku uurimiseks. Autori arvates on Vene propaganda taustal raske uurida ajalugu sine ira et studio ("ilma viha ja eelarvamusteta"), nagu soovitas president

Synthesis and up-conversion emissions of Yb3+/Er3+, Yb3+/Tm3+

Indian Academy of Sciences (India)

42

which has received considerable attention for material studies [25-28]. ... Though the energy gap between the ground state 8S7/2 and the first excited state 6P7/2 of ... XRD pattern (Figure 1a) of the 20 mol% Yb3+, 2 mol% Er3+ co-doped ...

Production and Quality Control of 177Lu-Dotatate [177Lu-dota- try3]-Octreotate: Clinical Application

International Nuclear Information System (INIS)

Barboza, M.F. de; Herrerias, R.; Souza, A.A. de; Pereira, G.; Pires, J.A.; Fukumori, N.T.O.; Matsuda, M.M.N.; Almeida, E.V.; Mengatti, J.; Belfer, A.J.; Hilario, L.N.

2009-01-01

Introduction: Somatostatin receptors have been identified in different kinds of tumors such as neuroendocrine tumors and tumors of the central nervous system, breast, lung and lymphatic tissue making these receptors potential targets for radionuclide diagnostics and therapy. These observations have served as the biomolecular basis for the clinical use of radiolabeled somatostatin analogues which, at present, are of great interest in nuclear medicine for diagnostic and peptide receptor radionuclide therapy (PRRT) applications. There are only a few treatment modalities for metastasized neuroendocrine gastroenteropancreatic (GEP) tumors. Besides surgery, (chemo)-embolization, chemotherapy, and treatment with somatostatin (SST) analogs, peptide receptor radionuclide therapy (PRRT) offers therapeutic strategy, as the majority of GEP tumors possess somatostatin receptors (SSTRs). Somatostatin analogs featuring a DOTA-chelator can be radiolabeled with the β-emitters radioisotopes, Yttrium-90 ( 90 Y) and Lutetium-177 ( 177 Lu) for PRRT. Analogs frequently used for therapy are: [DOTA-Tyr 3 ]-octreotide and [DOTA-Tyr 3 ]octreotate. In the latter compound, the alcohol threoninol at the C-terminal of the octreotide has been replaced by the natural threonin amino acid. This alteration resulted in an analog: (Tyr 3 -octreotate), which showed increased affinity for sst2, compared to both [Tyr 3 ]-octreotide and [Phe 1 ]octreotide 'in-vitro' and 'in-vivo'. Clinical studies in patients with different SST-positives tumors proved advantages of [ 177 Lu- DOTA-Tr 3 ]-octreate for therapy. PRRT with radiolabeled somatostatin analogs was shown to be effective in patients with SST2-positive-size reduction, improving quality of life and survival. Objective: The aim of this work was to present the production and the quality control of 177 Lu-Tyr 3 ---octreotate, using DOTA (1,4,7,10-tetrazacyclododecane-N,N',N',N''-tetra acetic acid) as chelating agent at the Radiopharmacy Directory, IPEN

Investigation of BaMoO4-Ln2(MoO4)3 systems (Ln = Nd, Sm, Yb)

International Nuclear Information System (INIS)

Vakulyuk, V.V.; Evdokimov, A.A.; Khomchenko, G.P.

1982-01-01

Using the methods of X-ray phase and differential-thermal analyses phase ratios in the systems BaMoO 4 -Ln 2 (MoO 4 ) 3 (Ln=Nd, Sm, Yb); BaNd 2 (MoO 4 ) 4 -MaGd 2 (MoO 4 ) are studied. Unit cell parameters and the character of melting of the compounds BaLn 2 (MoO 4 ) 4 are specified. Effect of growth conditions on laminated nature of BaGd 2 (MoO 4 ) 4 monocrystals is studied

Up-conversion luminescence of Er3+/Yb3+/Nd3+-codoped tellurite glasses

International Nuclear Information System (INIS)

Lu Longjun; Nie Qiuhua; Xu Tiefeng; Dai Shixun; Shen Xiang; Zhang Xianghua

2007-01-01

Up-conversion luminescence and energy transfer (ET) processes in Nd 3+ -Yb 3+ -Er 3+ triply doped TeO 2 -ZnO-Na 2 O glasses have been studied under 800 nm excitation. Intense green up-conversion emissions around 549 nm, which can be attributed to the Er 3+ : 4 S 3/2 →4 I 15/2 transition, are observed in triply doped samples. In contrast, the green emissions are hardly observed in Er 3+ singly doped and Er 3+ -Yb 3+ codoped samples under the same condition. Up-conversion luminescence intensity exhibits dependence of Yb 2 O 3 -concentration and Nd 2 O 3 -concentration. Up-conversion mechanism in the triply doped glasses under 800 nm pump is discussed by analyzing the ET among Nd 3+ , Yb 3+ and Er 3+ . And a possible up-conversion mechanism based on sequential ET from Nd 3+ to Er 3+ through Yb 3+ is proposed for green and red up-conversion emission processes

Characterization and Computation of Yb/TiO2 and Its Photocatalytic Degradation with Benzohydroxamic Acid

Directory of Open Access Journals (Sweden)

Xianping Luo

2017-11-01

Full Text Available Yb-doped TiO2 (Yb/TiO2 compositions were synthesized by sol-gel method, and the prepared materials were characterized by X-ray Diffraction (XRD, X-ray photoelectron spectroscopy (XPS, UV-visible diffuse-reflectance spectrum (UV-Vis DRS, transmission electron microscope (TEM and high resolution transmission electron microscope (HRTEM, energy dispersive spectrometer (EDS, and N2 adsorption. A beneficiation reagent of benzohydroxamic acid (BHA was used to test the photocatalytic activity of Yb/TiO2. The characterizations indicate that the doping of Yb could inhibit the crystal growth of TiO2, enhance the specific surface area, increase the binding energy of Ti2p, and also slightly expand the adsorption ranges to visible light. Furthermore, the computation of band structure also indicates that Yb-doped TiO2 could make the forbidden band narrower than pure anatase TiO2, which presents a red shift in the absorption spectrum. As a result of the photodegradation experiment on BHA, Yb/TiO2 (0.50% in mass sintered at 450 °C displayed the highest catalytic activity for BHA when compared with pure TiO2 or other doped Yb/TiO2 compositions, and more than 89.2% of the total organic carbon was removed after 120 min. Almost all anions, including Cl−, HCO3−, NO3−, and SO42−, inhibited the degradation of BHA by Yb/TiO2, and their inhibition effects followed the order of HCO3− > NO3− > SO42− > Cl−. Cations of Na+, K+, Ca2+, and Mg2+ displayed a slight suppressing effect due to the impact of Cl− coexisting in the solution. In addition, Yb/TiO2 maintained a high photocatalytic ability with respect to BHA after four runs. It is hypothesized that ·OH is one of the main species involved in the photodegradation of BHA, and the mutual transformation of Yb3+ and Yb2+ could promote the separation of electron-hole pairs.

CW Yb:YAG LASER FOR PORTABLE MEASURING SYSTEMS

Directory of Open Access Journals (Sweden)

A. M. Ivashko

2014-01-01

Full Text Available The theoretical and experimental results of longitudinally continuous-wave diode-pumped Yb:Y3Al5O12 (YAG laser performance for compact field-condition measuring systems were demonstrated. Optimization of laser setup in terms of operation condition in the range of -40 ˚С – +65 ˚С without active thermal stabilization was carried out. Using Yb (10 ат.%:YAG crystal with the length of 3 mm the maximal output power more than 2 W was obtained in the whole of temperature range.

Electronic structure of YbNiX{sub 3} (X =Si, Ge) studied by hard X-ray photoemission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sato, Hitoshi; Shimada, Kenya; Namatame, Hirofumi [Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima 739-0046 (Japan); Utsumi, Yuki [Max-Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany); Kodama, Junichi; Nagata, Heisuke [Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan); Avila, Marcos A.; Ribeiro, Raquel A. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Santo Andre - SP, 09210-580 (Brazil); Umeo, Kazunori [Cryogenics and Instrumental Analysis Division, N-BARD, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan); Takabatake, Toshiro [Department of Quantum Matter, AdSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Institute for Advanced Materials Research, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Mimura, Kojiro; Motonami, Satoru; Anzai, Hiroaki [Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Ueda, Shigenori [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Hyogo 679-5148 (Japan); Taniguchi, Masaki [Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima 739-0046 (Japan); Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)

2015-06-15

lectronic structure of the Kondo lattices YbNiX{sub 3} (X =Si, Ge) has been investigated by means of hard x-ray photoemission spectroscopy (HAXPES) with hν = 5.95 keV. From the Yb 3d HAXPES spectra, the Yb valence in YbNiSi{sub 3} is estimated to be ∝ 2.92, which is almost temperature-independent. On the other hand, the valence in YbNiGe{sub 3} is estimated to be 2.48 at 300 K, showing significant valence fluctuation, and gradually decreases to 2.41 at 20 K on cooling. The Ni 2p{sub 3/2} and Yb{sup 3+} 4f peaks exhibit opposite energy shifts amounting to ∝ 0.6 eV between YbNiSi{sub 3} and YbNiGe{sub 3}. We propose a simple model for the electronic structure of YbNiX{sub 3} based on the HAXPES results. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Treatment of Neuroblastoma with an Engineered "Obligate" Anaerobic Salmonella typhimurium Strain YB1.

Science.gov (United States)

Ning, Bo-Tao; Yu, Bin; Chan, Shing; Chan, Jian-Liang; Huang, Jian-Dong; Chan, Godfrey Chi-Fung

2017-01-01

Purpose Neuroblastoma is an embryonic solid tumor derived from the progenitors of the sympathetic nervous system. More than half of the patients developed metastatic disease at the time of initial diagnosis and had poor outcome with current therapeutic approaches. In recent years, some obligate and facultative anaerobic bacteria were reported to target the hypoxic and necrotic region of solid tumor models and caused tumor regression. We recently successfully constructed an "obligate" anaerobic Salmonella strain YB1 that was applied in breast cancer nude mice model by us. Here, we report the application of YB1 in neuroblastoma treatment. Methods The anti-cancer effect and side-effects of YB1 was examined in both in vitro and in vivo experiment. Previous established orthotopic neuroblastoma SCID/beige murine model using SK-NLP/luciferase cell line was adopted. Results In vitro , YB1 induced apoptosis for up to 31.4% of the neuroblastoma cells under anaerobic condition, three times more than that under aerobic condition (10.9%). The expression of both Toll like Receptor 4 and 5 (TLR4 and TLR5) in cancer cells were significantly up-regulated ( p anaerobic condition. In mouse model, YB1 preferentially accumulated inside the core of the tumors, rather than in normal tissues as our previous reported. This is suggestive of the hypoxic nature of tumor core. Tumor growth was significantly retarded in YB1 treatment group ( n=6, P<0.01 ). Furthermore, there was no long-term organ damage noted in all the organs examined including heart, lung, liver, spleen and brain in the YB1 treated mice. Conclusion The genetic modified Salmonella strain YB1 is a promising anti-tumor strategy against the tumor bulk for neuroblastoma. Future study can be extended to other common cancer types to verify the relative efficacy on different neoplastic cells.

Comparative study of optical and scintillation properties of YVO{sub 4}, (Lu{sub 0.5}Y{sub 0.5})VO{sub 4}, and LuVO{sub 4} single crystals

Energy Technology Data Exchange (ETDEWEB)

Fujimoto, Yutaka, E-mail: fuji-you@tagen.tohoku.ac.j [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yanagida, Takayuki; Yokota, Yuui; Chani, Valery [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kochurikhin, Vladimir V. [General Physics Institute, 38 Vavilov Street, 119991, Federation, Moscow (Russian Federation); Yoshikawa, Akira [IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); NICHe, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

2011-04-11

Optical and scintillation properties of YVO{sub 4}, (Lu{sub 0.5}Y{sub 0.5})VO{sub 4}, and LuVO{sub 4} single crystals grown by the Czochralski (CZ) method with RF heating system are compared. All vanadate crystals show high transmittance ({approx}80%) in the 400-900 nm wavelength range. In both photo- and radio-luminescence spectra, intense peak around 400-500 nm, which was ascribed to the transition from triplet state of VO{sub 4}{sup 3-}, was clearly observed. The main decay time component was about 38 {mu}s (YVO{sub 4}), 18 {mu}s ((Lu{sub 0.5}Y{sub 0.5})VO{sub 4}), and 17 {mu}s (LuVO{sub 4}) under 340 nm excitation. The scintillation light yields of YVO{sub 4}, (Lu{sub 0.5}Y{sub 0.5})VO{sub 4}, and LuVO{sub 4} crystals (obtained from the {sup 137}Cs excited pulse height spectra) were evaluated to be about 11,200, 10,700, and 10,300 ph/MeV, respectively.

Magnetic propertiesof Lu.sub.2./sub.Fe.sub.16./sub.X (X = Fe, Ni, Cr, Si) intermetallics under high hydrostatic pressure

Czech Academy of Sciences Publication Activity Database

Kamarád, Jiří; Andreev, Alexander V.; Machátová, Zuzana; Arnold, Zdeněk

408-412, - (2006), s. 151-154 ISSN 0925-8388 R&D Projects: GA ČR(CZ) GA202/02/0739; GA MŠk(CZ) ME 495 Institutional research plan: CEZ:AV0Z10100521 Keywords : intermetallic compounds * Lu 2 Fe 17 * magnetic properties * high pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.250, year: 2006

177Lu-DOTA-Bevacizumab: Radioimmunotherapy Agent for Melanoma.

Science.gov (United States)

Camacho, Ximena; Calzada, Victoria; Fernandez, Marcelo; Alonso, Omar; Chammas, Roger; Riva, Eloisa; Gambini, Juan Pablo; Cabral, Pablo

2017-01-01

Vascular endothelial growth factor (VEGF) is one of the classic factors to tumor-induced angiogenesis in several types, including melanoma. Bevacizumab is a humanized monoclonal antibody directed against VEGF. To radiolabel Bevacizumab with 177-Lutetium as a potential radioimmunotherapy agent for melanoma. Bevacizumab was derivatized with DOTA-NHS-ester at 4 ºC for 18 h. DOTABevacizumab was radiolabeled with 177LuCl3 (15 MBq/mg) at 37 ºC for 1 h. The studies were performed in healthy and B16F1 tumor-bearing C57BL/6J mice at 24 and 48 h (n = 5). Scinthigraphic imaging studies were performed at 24 h to determine the radiochemical stability, targeting specificity and pharmacokinetics of the 177Lutetium-labeled antibody. DOTA-Bevacizumab was efficiently labeled with 177LuCl3 at 37 °C. The in-vitro stability of labeled product was optimal over 72 h. In-vivo biodistribution studies showed a high liver and tumor uptake of 177Lu-DOTA-Bevacizumab, with tumor-to-muscle ratios of 11.58 and 6.37 at 24 and 48 h p.i. Scintigraphic imaging of melanoma tumor-bearing C57BL/6J mice showed liver and a high tumor selective uptake of 177Lu-DOTA-Bevacizumab at 24 h. Our results support the potential role of 177Lu-DOTA-Bevacizumab as a novel radioimmunotherapy agent for melanoma. We hope that these novel molecular imaging agents will open the path to new diagnostic and therapeutic strategies for Melanoma disease. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Magnetic susceptibility of YbN

International Nuclear Information System (INIS)

Zhou, Y.; Bowen, S.P.; Koelling, D.D.; Monnier, R.

1991-01-01

Applying the Zwicknagl, Zevin, and Fulde (ZZF) approximation for the spectral densities of the occupied and empty f states resulting from a degenerate-Anderson-impurity model, which incorporates crystal fields, we compute the low-temperature magnetic susceptibility of YbN. The model, in which each crystal-field level couples to the band states with its own hybridization function, has previously been successfully applied without the ZZF approximation to explain the specific-heat structure at low temperatures. The ZZF approximation removes the spurious zero-temperature behavior of the parent noncrossing approximation for the susceptibility. Surprisingly, even at the low crystal-field degeneracy (N=2) of YbN, the Shiba relation is very nearly satisfied. The appropriate experimental impurity susceptibility for comparison is extracted from the measurement by removing an empirical exchange interaction. The resultant Kondo temperature (T 0 =8.49 K) is consistent with previous specific-heat estimates (10--11 K), and the agreement with experiment is good

Green and red luminescence in co-precipitation synthesized Pr:LuAG nanophosphor

Energy Technology Data Exchange (ETDEWEB)

Kumar, S. Arun; Kumar, K. Ashok; Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai–600 025, Tamil Nadu (India); Asokan, K. [Materials Science Group, Inter University Accelerator Centre, New Delhi-110067 (India)

2016-05-06

Pr:LuAG nanophosphor is an effective candidate in magnetic resonance imaging coupled positron emission tomography (MRI-PET) for medical imaging and scintillator applications. LuAG:Pr (0.05, 0.15 mol%) nanoscale ceramic powders were synthesized by co-precipitation method using urea as precipitant. Effect of antisite defect on structure and luminescence behavior was investigated. Pr:LuAG nanoceramic powders are found crystallized in cubic structure by high temperature calcination at 1400 °C and it shows antisite defect. HR-SEM analysis revealed spherically shaped Pr:LuAG nanoceramic particulate powders with ∼100 nm size. By the excitation at 450 nm, Pr:LuAG nanophosphor exhibit green to red luminescence in the wavelength range of 520 to 680 nm, which is originated from multiplet transition of Pr{sup 3+} ions.

Direct Comparison of Yb.sup.3+./sup.:CaF.sub.2./sub. and heavily doped Yb.sup.3+./sup.:YLF as laser media at room temperature

Czech Academy of Sciences Publication Activity Database

Pirri, A.; Alderighi, D.; Toci, G.; Vannini, M.; Nikl, Martin; Sato, H.

2009-01-01

Roč. 17, č. 20 (2009), s. 18312-18319 ISSN 1094-4087 Grant - others:AV ČR(CZ) M100100910 Institutional research plan: CEZ:AV0Z10100521 Keywords : Yb 3+ :YLF * Yb 3+ :CaF 2 * solid state laser * diode pumped Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.278, year: 2009

Recent experiments at Brookhaven: level structure of N = 86 isotones 156Yb and 150Gd

International Nuclear Information System (INIS)

Sunyar, A.W.

1980-01-01

States of the N = 86 isotones 156 Yb and 150 Gd have been studied by means of the 144 Sm( 16 O,4n) 156 Yb, 113 In( 46 Ti,p2n) 156 Yb, and 124 Sn( 30 Si,4n) 150 Gd reactions. Levels have been established to spin 36 h-bar and over 12.5 MeV in excitation in 150 Gd and to beyond spin 25 h-bar in 156 Yb. The systematics of levels in the N = 86 isotones from 150 Gd to 156 Yb are described, and the near-spherical shell model description for states in this region to near spin 30 h-bar is discussed. A T/sub 1/2/ = 6 ns, 72-keV isomeric transition in 156 Yb has been discovered, and an E1 multipolarity is assigned to this transition. The spin-parity of the isomeric state is established as 11 - . 6 figures

High-average-power diode-pumped Yb: YAG lasers

International Nuclear Information System (INIS)

Avizonis, P V; Beach, R; Bibeau, C M; Emanuel, M A; Harris, D G; Honea, E C; Monroe, R S; Payne, S A; Skidmore, J A; Sutton, S B

1999-01-01

A scaleable diode end-pumping technology for high-average-power slab and rod lasers has been under development for the past several years at Lawrence Livermore National Laboratory (LLNL). This technology has particular application to high average power Yb:YAG lasers that utilize a rod configured gain element. Previously, this rod configured approach has achieved average output powers in a single 5 cm long by 2 mm diameter Yb:YAG rod of 430 W cw and 280 W q-switched. High beam quality (M(sup 2)= 2.4) q-switched operation has also been demonstrated at over 180 W of average output power. More recently, using a dual rod configuration consisting of two, 5 cm long by 2 mm diameter laser rods with birefringence compensation, we have achieved 1080 W of cw output with an M(sup 2) value of 13.5 at an optical-to-optical conversion efficiency of 27.5%. With the same dual rod laser operated in a q-switched mode, we have also demonstrated 532 W of average power with an M(sup 2) and lt; 2.5 at 17% optical-to-optical conversion efficiency. These q-switched results were obtained at a 10 kHz repetition rate and resulted in 77 nsec pulse durations. These improved levels of operational performance have been achieved as a result of technology advancements made in several areas that will be covered in this manuscript. These enhancements to our architecture include: (1) Hollow lens ducts that enable the use of advanced cavity architectures permitting birefringence compensation and the ability to run in large aperture-filling near-diffraction-limited modes. (2) Compound laser rods with flanged-nonabsorbing-endcaps fabricated by diffusion bonding. (3) Techniques for suppressing amplified spontaneous emission (ASE) and parasitics in the polished barrel rods

Microscopic evidence for significant ionic disorder in the Yb sup 3 sup + -chain in Yb sub 4 (As sub 1 sub - sub x P sub x) sub 3 : sup 3 sup 1 P NMR studies

CERN Document Server

Tanida, H; Aoki, H; Ochiai, A

2003-01-01

We report unambiguous microscopic evidence from sup 3 sup 1 P NMR under H sub e sub x sub t approx = 7.3 T for significant ionic disorder in the Yb sup 3 sup + chain in Yb sub 4 (As sub 1 sub - sub x P sub x) sub 3 (x=0.05 and 0.40), which have similar characteristic chi(T) and C sub p (T, H sub e sub x sub t) behavior to the antiferromagnetic quantum spin chain (AFQSC) system Yb sub 4 As sub 3. Our conclusion is based on the observations only below the charge-ordering transition at T sub 0 approx = 292 K of clear structures in the spectrum, which can be fitted well by the superpositions of almost equally spaced five Gaussian components. Since perfect ordering of Yb sup 3 sup + in the chain sites would lead to a single-line spectrum also below T sub 0 , the structures should be ascribed to significant ionic disorder in the Yb sup 3 sup + chain and resulting distribution of local configurations of Yb sup 3 sup + in the eight nearest-neighboring Yb sites around sup 3 sup 1 P. Quantitative comparisons with a sim...

Structural and magnetic properties of two branches of the tripod-kagome-lattice family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb)

Science.gov (United States)

Dun, Z. L.; Trinh, J.; Lee, M.; Choi, E. S.; Li, K.; Hu, Y. F.; Wang, Y. X.; Blanc, N.; Ramirez, A. P.; Zhou, H. D.

2017-03-01

We present a systematic study of the structural and magnetic properties of two branches of the rare-earth tripod-kagome-lattice (TKL) family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation A-R, as in MgPr for Mg2Pr3Sb3O14 ), which complements our previously reported work on MgDy, MgGd, and MgEr [Z. L. Dun et al., Phys. Rev. Lett. 116, 157201 (2016), 10.1103/PhysRevLett.116.157201]. The present susceptibility (χdc, χac) and specific-heat measurements reveal various magnetic ground states, including the nonmagnetic singlet state for MgPr, ZnPr; long-range orderings (LROs) for MgGd, ZnGd, MgNd, ZnNd, and MgYb; a long-range magnetic charge ordered state for MgDy, ZnDy, and potentially for MgHo; possible spin-glass states for ZnEr, ZnHo; the absence of spin ordering down to 80 mK for MgEr, MgTb, ZnTb, and ZnYb compounds. The ground states observed here bear both similarities as well as striking differences from the states found in the parent pyrochlore systems. In particular, while the TKLs display a greater tendency towards LRO, the lack of LRO in MgHo, MgTb, and ZnTb can be viewed from the standpoint of a balance among spin-spin interactions, anisotropies, and non-Kramers nature of single-ion state. While substituting Zn for Mg changes the chemical pressure, and subtly modifies the interaction energies for compounds with larger R ions, this substitution introduces structural disorder and modifies the ground states for compounds with smaller R ions (Ho, Er, Yb).

Y-box-binding protein-1 (YB-1) promotes cell proliferation, adhesion and drug resistance in diffuse large B-cell lymphoma

Energy Technology Data Exchange (ETDEWEB)

Miao, Xiaobing; Wu, Yaxun [Department of Pathology, Affiliated Cancer Hospital of Nantong University, Nantong 226361, Jiangsu (China); Wang, Yuchan [Department of Pathogen, Medical College, Nantong University, Nantong 226001, Jiangsu (China); Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong 226001, Jiangsu (China); Zhu, Xinghua; Yin, Haibing [Department of Pathology, Affiliated Cancer Hospital of Nantong University, Nantong 226361, Jiangsu (China); He, Yunhua [Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong 226001, Jiangsu (China); Li, Chunsun; Liu, Yushan; Lu, Xiaoyun; Chen, Yali; Shen, Rong [Department of Pathology, Affiliated Cancer Hospital of Nantong University, Nantong 226361, Jiangsu (China); Xu, Xiaohong, E-mail: xuxiaohongnantong@126.com [Department of Oncology, Affiliated Cancer Hospital of Nantong University, Nantong 226361, Jiangsu (China); He, Song, E-mail: hesongnt@126.com [Department of Pathology, Affiliated Cancer Hospital of Nantong University, Nantong 226361, Jiangsu (China)

2016-08-15

YB-1 is a multifunctional protein, which has been shown to correlate with resistance to treatment of various tumor types. This study investigated the expression and biologic function of YB-1 in diffuse large B-cell lymphoma (DLBCL). Immunohistochemical analysis showed that the expression statuses of YB-1 and pYB-1{sup S102} were reversely correlated with the clinical outcomes of DLBCL patients. In addition, we found that YB-1 could promote the proliferation of DLBCL cells by accelerating the G1/S transition. Ectopic expression of YB-1 could markedly increase the expression of cell cycle regulators cyclin D1 and cyclin E. Furthermore, we found that adhesion of DLBCL cells to fibronectin (FN) could increase YB-1 phosphorylation at Ser102 and pYB-1{sup S102} nuclear translocation. In addition, overexpression of YB-1 could increase the adhesion of DLBCL cells to FN. Intriguingly, we found that YB-1 overexpression could confer drug resistance through cell-adhesion dependent and independent mechanisms in DLBCL. Silencing of YB-1 could sensitize DLBCL cells to mitoxantrone and overcome cell adhesion-mediated drug resistance (CAM-DR) phenotype in an AKT-dependent manner. - Highlights: • The expression statuses of YB-1 and pYB-1{sup S102} are reversely correlated with outcomes of DLBCL patients. • YB-1 promotes cell proliferation by accelerating G1/S transition in DLBCL. • YB-1 confers drug resistance to mitoxantrone in DLBCL.

FP-LAPW study of the elastic properties of Al2X (X=Sc,Y,La,Lu)

International Nuclear Information System (INIS)

Rajagopalan, M.; Praveen Kumar, S.; Anuthama, R.

2010-01-01

From the first principles total energy calculations based on full-potential linear augmented plane wave method (FP-LAPW), the elastic properties of Al 2 X (X=Sc,Y,La,Lu) are reported here. Theoretical values of Young's modulus, shear modulus, Poisson's ratio and Debye temperature are estimated from the computed elastic constants. From the analysis of the ratio of shear to bulk modulus, it is found that these intermetallic compounds are brittle in nature. The calculated results are compared with other reported values.

Improving the photoluminescence response of Er-Tm: Al2O3 films by Yb codoping

International Nuclear Information System (INIS)

Xiao Zhisong; Serna, R.; Afonso, C.N.; Cheng Guoan; Vickridge, I.

2007-01-01

Amorphous Al 2 O 3 films doped with Er, Tm and Yb have been prepared by pulsed laser deposition. A broadband emission in the range 1400-1700 nm with two peaks around 1540 and 1640 nm has been observed, both in the Er-Tm and Er-Tm-Yb codoped films. The Tm-related photoluminescence (PL) intensity at 1640 nm is enhanced when codoping with Yb thus suggesting the existence of multiple energy transfer processes from Yb to Er and Er to Tm. The Er-Tm-Yb codoped film exhibits a broadband emission with a full-width half-maximum of 184 nm similar to that of the film codoped with Tm and Er but having higher Tm to Er concentration ratio and higher PL lifetime values

Synthesis and thermoelectric properties of rare earth Yb-doped Ba8−xYbxSi30Ga16 clathrates

International Nuclear Information System (INIS)

Liu, Lihua; Li, Feng; Wei, Yuping; Chen, Ning; Bi, Shanli; Qiu, Hongmei; Cao, Guohui; Li, Yang

2014-01-01

Highlights: • Samples with the chemical formula Ba8− x Yb x Si 30 Ga 16 (x = 0, 0.5, 0.7, 1 and 1.5) were prepared. • Some Yb atoms enter the clathrate lattice to replace Ba, while other Yb atoms are oxidized as Yb 2 O 3 . • The thermal conductivity decreases with Yb-doping. • Thermoelectric figure of merit ZT significantly increased. -- Abstract: The potential thermoelectric and magnetic application of clathrate materials with rare-earth doping is the focus of much of the recent research activity in the synthetic material physics and chemistry. A series of clathrate samples with the chemical formula Ba 8−x Yb x Si 30 Ga 16 (x = 0, 0.5, 0.7, 1 and 1.5) were prepared by combining arc melting, ball milling and spark plasma sintering (SPS) techniques. X-ray diffraction and scanning electronic microscopy combined with energy-dispersive X-ray spectroscopy (EDS) analysis showed the dominant phase to be the type-I clathrate. Whereas, X-ray structural refinement and EDS analysis indicated that some Yb atoms enter the clathrate lattice to replace Ba at 2a sites, while other Yb atoms are oxidized as Yb 2 O 3 precipitated around grain boundaries. The solid solubility of Yb into clathrate lattice yielded x ∼ 0.3. Comparative analysis between Yb-doped and Yb-free clathrates showed that the thermal conductivity decreases with Yb-doping. Consequently, thermoelectric figure of merit ZT significantly increased

Dependence of upconversion emission intensity on Yb3+ concentration in Er3+/Yb3+ co-doped flake shaped Y2(MoO4)3 phosphors

International Nuclear Information System (INIS)

Lu Weili; Cheng Lihong; Zhong Haiyang; Sun Jiashi; Wan Jing; Tian Yue; Chen Baojiu

2010-01-01

Yttrium molybdate phosphors with fixed Er 3+ and various Yb 3+ concentrations were synthesized via a co-precipitation method. The crystal structure and the morphology of the phosphor were characterized by means of x-ray diffraction and field-emission scanning electron microscopy. Under 980 nm excitation, red and green upconversion emissions centred at 660, 553 and 530 nm were observed. Quantitative analyses on the dependence of upconversion emission intensity on the working current of a laser diode (LD) indicated that two-photon processes are responsible for both red and green upconversion emissions in both cases of low and high Yb 3+ concentrations. The relationship between the emission intensity ratio of 2 H 11/2 → 4 I 15/2 to 4 S 3/2 → 4 I 15/2 and the working current of the LD was studied for the samples doped with low and high Yb 3+ concentrations. Finally, a set of rate equations was established based on the possible upconversion mechanism, and an empirical formula was proposed to describe the Yb 3+ concentration dependence of upconversion emission intensity; the empirical formula fits well with the experimental data.

Optimization of LSO/LuYAP phoswich detector for small animal PET

International Nuclear Information System (INIS)

Jung, Jin Ho; Choi, Yong; Chung, Yong Hyun; Devroede, Olivier; Krieguer, Magalie; Bruyndonckx, Peter; Tavernier, Stefaan

2007-01-01

LSO/LuYAP phoswich detectors for small animal PET were developed to measure the depth of interaction (DOI), and to improve the spatial resolution at the edge of the field of view (FOV). The aim of this study was to optimize the optical coupling conditions between the crystal and photomultiplier tube (PMT) to maximize the light-collection efficiency, and to develop a method for rejecting scatter events by applying an equal energy window in each crystal layer. The light yields of the phoswich detector were estimated by changing the refractive index of the optical coupling material using a DETECT simulation. The accuracy of the DOI measurement on the phoswich detector, using an optical coupling material with the optimal light yield, were evaluated experimentally and compared with the air condition. The energy window for the photopeak events cannot be applied properly because the light outputs of LSO and LuYAP are different. The LSO/LuYAP photopeaks need to be superposed in order to effectively discriminate the scattered events by applying an equal energy window. The photopeaks of the LSO and LuYAP can be superposed by inserting a reflecting material between the crystals. The optimal coverage ratio of the inserting material was derived from a DETECT simulation, and its performance was investigated. In the simulation result, optimal refractive index of the optical coupling material was 1.7. The average DOI measurement errors of the LSO/LuYAP were 0.6%/3.4% and 4.9%/41.4% in the phoswich detector with and without an optical coupling material, respectively. The photopeaks of the LSO and LuYAP were superposed by covering 75% of the contact surface between the crystals with white Teflon. The DOI measurement errors of the LSO/LuYAP were 0.2%/2.4%. In this study, the optimal condition of the optical coupling material inserted between the crystal and PMT was derived to improve the accuracy of DOI measurement, and a photopeak superposition method of the LSO and LuYAP was

Overview of ultraviolet and infrared spectroscopic properties of Yb{sup 3+} doped borate and oxy-borates compounds; De l'ultraviolet a l'infrarouge: caracterisation spectroscopique de materiaux type borate et oxyborate dopes a l'ytterbium trivalent

Energy Technology Data Exchange (ETDEWEB)

Sablayrolles, J

2006-12-15

The trivalent ytterbium ion can give rise to two emissions with different spectroscopic properties: the first one, with a short lifetime, in the ultraviolet (charge transfer emission) is used in detectors such as scintillators, and the other one, with a long lifetime, in the infrared (4f-4f emission) for laser applications. The strong link between material structure and properties is illustrated through ytterbium luminescence study, in the ultraviolet and infrared, inserted in the borate Li{sub 6}Y(BO{sub 3}){sub 3} and two oxy-borates: LiY{sub 6}O{sub 5}(BO{sub 3}){sub 3} and Y{sub 17,33}B{sub 8}O{sub 38}. For the first time an ytterbium charge transfer emission in oxy-borates has been observed. The calculation of the single configurational coordinate diagram, as well as the thermal quenching, has been conducted under a fundamental approach on the ytterbium - oxygen bond. The study of the ytterbium infrared spectroscopy in these compounds has been realised and an energy level attribution is proposed in the particular case of the borate Li{sub 6}Y(BO{sub 3}){sub 3}: Yb{sup 3+}. An original approach is introduced with the study of the charge transfer states for the three compounds by looking at the infrared emission. The first laser performances in three operating modes (continuous wave, Q-switch and mode locking) of a Li{sub 6}Y(BO{sub 3}){sub 3}: Yb{sup 3+} crystal are reported. (author)

Synthesis and characterization of Nd3+: Yb3+ co-doped near infrared sensitive fluorapatite nanoparticles as a bioimaging probe

Science.gov (United States)

Karthi, S.; Kumar, G. A.; Sardar, D. K.; Santhosh, C.; Girija, E. K.

2018-03-01

Trivalent Nd and Yb co-doped rod shaped hexagonal phase fluorapatite (FAP) nanoparticles of length and width about 32 and 13 nm, respectively were prepared by hydrothermal method and investigated the ability for 980 nm emission via Nd3+ → Yb3+ energy transfer with the objective of utilizing them in biomedical imaging. Nd3+ → Yb3+ energy transfer in FAP was studied as a function of both Nd3+ and Yb3+ concentrations and found that when Yb3+ concentration was 10 mol% the FAP phase has partially turned in to YbPO4 phase. The Yb3+ emission intensity at 980 nm significantly increased up to 5 mol% Yb3+ doping and then reduced drastically for further increase in its concentration. Nd3+ →Yb3+ energy transfer rates were evaluated from the decay curves and found that a transfer rate of 71% for 2 mol% Nd3+ co-doped with 5 mol% Yb3+. The cytocompatibility test with fibroblast like cells using MTT assay revealed that the nanoparticles are compatible with the cells.

Formation enthalpies of LaLn'O{sub 3} (Ln'=Ho, Er, Tm and Yb) interlanthanide perovskites

Energy Technology Data Exchange (ETDEWEB)

Qi, Jianqi [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Laboratory of High Energy Density Physics of Ministry of Education, Sichuan University, Chengdu 610064 (China); Guo, Xiaofeng [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States); Mielewczyk-Gryn, Aleksandra [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States); Faculty of Applied Physics and Mathematics, Department of Solid State Physics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk (Poland); Navrotsky, Alexandra, E-mail: anavrotsky@ucdavis.edu [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States)

2015-07-15

High-temperature oxide melt solution calorimetry using 3Na{sub 2}O·MoO{sub 3} at 802 °C was performed for interlanthanide perovskites LaLn'O{sub 3} (Ln'=Ho, Er, Tm and Yb) and lanthanide oxides (La{sub 2}O{sub 3}, Ho{sub 2}O{sub 3}, Er{sub 2}O{sub 3}, Tm{sub 2}O{sub 3} and Yb{sub 2}O{sub 3}). The enthalpies of formation of these interlanthanide perovskites from binary lanthanide oxides at room temperature (25 °C) were determined to be −8.3±3.4 kJ/mol for LaHoO{sub 3}, −9.9±3.0 kJ/mol for LaErO{sub 3}, −10.8±2.7 kJ/mol for LaTmO{sub 3} and −12.3±2.9 kJ/mol for LaYbO{sub 3}. There is a roughly linear relationships between these enthalpy values and the tolerance factor for these and for other LaM{sup 3+}O{sub 3} (M=In, Sc, Ga, Al, Fe and Cr) perovskites, confirming that the distortion of the perovskites as results from ionic radius difference of A-site and B-site cations, is the main factor determining the stability of these compounds. - Graphical abstract: A linear relationship between the enthalpy of formation and the tolerance factor for interlanthanide LaLn'O{sub 3} (Ln'=Ho, Er, Tm, and Yb) and other LaM{sup 3+}O{sub 3} (M=In, Sc, Ga, Al, Fe and Cr) perovskites. - Highlights: • Interlanthanide perovskites were synthesized by solid state reactions. • Their enthalpies of formation were measured by oxide melt solution calorimetry. • ΔH{sub f,ox} shows a linear relationship with tolerance factor.

Surface magnetic phase transitions in Dy/Lu superlattices

International Nuclear Information System (INIS)

Goff, J.P.; Sarthour, R.S.; Micheletti, C.; Langridge, S.; Wilkins, C.J.T.; Ward, R.C.C.; Wells, M.R.

1999-01-01

Dy/Lu superlattices comprising ferromagnetic Dy blocks coupled antiferromagnetically across the Lu blocks may be modelled as a chain of XY spins with antiferromagnetic exchange and six-fold anisotropy. We have calculated the stable magnetic phases for the cases of large anisotropy and a field applied along an easy direction. For an infinite chain an intermediate phase (1, 5,...) is predicted, where the notation gives the angle between the moment and the applied field in units of π/3. Furthermore, the effects of surface reconstruction are determined for finite chains. A [Dy 20 Lu 12 ] 20 superlattice has been studied using bulk magnetization and polarized neutron reflectivity. The (1, 5,...) phase has been identified and the results provide direct evidence in support of the theoretical predictions. Dipolar forces are shown to account for the magnitude of the observed exchange coupling. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Rare earth-transition metal indides with Lu{sub 5}Ni{sub 2}In{sub 4}-type structure

Energy Technology Data Exchange (ETDEWEB)

Zaremba, Roman; Hermes, Wilfried; Eul, Matthias; Poettgen, Rainer [Inst. fuer Anorganische und Analytische Chemie, Univ. Muenster (Germany)

2008-12-15

New intermetallic compounds RE{sub 5}T{sub 2}In{sub 4} (RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu; T = Rh, Ir) were synthesized by arc-melting of the elements or by induction melting of the elements in tantalum crucibles under flowing argon. The samples were characterized by X-ray powder diffraction. They crystallize with the orthorhombic Lu{sub 5}Ni{sub 2}In{sub 4}-type structure, space group Pbam, Z = 2, a 2: 1 intergrowth variant of CsCl and AlB{sub 2} related slabs of compositions InRE{sub 8} (distorted cubes) and RhRE{sub 6} (distorted trigonal prisms). Susceptibility measurements of Ce{sub 5}Ir{sub 2}In{sub 4} have revealed modified Curie-Weiss behavior above 70 K with an experimental magnetic moment of 2.45(1) {mu}{sub B} / Ce atom. The cerium magnetic moments order ferri- or ferromagnetically at T{sub C} = 7.1(2) K. (orig.)

A better ferrimagnetic half-metal LuCu{sub 3}Mn{sub 4}O{sub 12}: Predicted from first-principles investigation

Energy Technology Data Exchange (ETDEWEB)

Lv Shuhui; Li Hongping [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Han Deming; Wu Zhijian [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Liu Xiaojuan, E-mail: lxjuan@ciac.jl.c [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Meng Jian, E-mail: jmeng@ciac.jl.c [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2011-03-15

Electronic structure calculations based on density functional theory (DFT) within the generalized gradient approximation (GGA) and GGA+U for manganite cuprate compound LuCu{sub 3}Mn{sub 4}O{sub 12} have been performed, using the full-potential linearized augmented plane wave method. The calculated results indicate that LuCu{sub 3}Mn{sub 4}O{sub 12} is ferrimagnetic and half-metallic in both GGA and GGA+U calculations. The minority-spin band gap is 0.7 eV within GGA, which is larger than that of LaCu{sub 3}Mn{sub 4}O{sub 12} (0.3 eV), indicating its better half-metallicity. Further, the minority-spin gap enlarges from 0.7 to 2.8 eV with U taken into account, and simultaneously the Fermi level being shifted to the middle of the gap, making the half-metallic energy gap to be 1.21 eV. These results demonstrate that electronic correlation effect enhances the stability of half-metallic property. These facts make this system interesting candidates for applications in spintronic devices. - Research highlights: The electronic and magnetic properties of LuCu{sub 3}Mn{sub 4}O{sub 12} are analyzed. Both GGA and GGA+U methods are reported and compared. A better half-metal LuCu{sub 3}Mn{sub 4}O{sub 12} is obtained with large half-metallic gap. The results agree very well with the experimental data.

Upconversion dynamics in Yb3+-Ho3+-doped fluoroindate glasses

International Nuclear Information System (INIS)

Martin, I.R.; Rodriguez, V.D.; Lavin, V.; Rodriguez-Mendoza, U.R.

1998-01-01

The mechanisms and dynamics of the upconversion emissions in Yb 3+ -Ho 3+ -doped fluoroindate glasses by exciting at 975 nm have been analysed. The upconversion efficiencies have been measured as a function of temperature in the range from 12 to 295 K. The temporal evolution of the 545- and 650-nm upconversion emissions obtained under flash excitation at 975 nm in codoped samples with 2.25 mol.% of Yb 3+ and 0.75 mol.% of Ho 3+ cannot be described using the energy migration model. This indicates that at this concentration of Yb 3+ the rapid migration regimen between these ions has not been reached. A model is proposed in order to explain the temporal evolution of these emissions taking into account energy migration between donors and backtransfer processes. (orig.)

Laser induced broad band anti-Stokes white emission from LiYbF4 nanocrystals

Institute of Scientific and Technical Information of China (English)

L. Marciniak; R. Tomala; M. Stefanski; D. Hreniak; W. Strek

2016-01-01

Spectroscopic properties of tetragonal LiYbF4 nanocrystals under high dense NIR excitation at vacuum condition were in-vestigated. White, broad band emission covering whole visible part of the spectrum from LiYbF4 nanocrystals was observed. Its in-tensity strongly depended on the excitation power, excitation wavelength and ambient pressure. Temperature of the nanocrystals un-der 975 nm excitation was determined as a function of excitation power. Strong photo-induced current was observed from LiYbF4 pallet. The emission kinetic was analyzed. The mechanism of the anti-Stokes white emission was discussed in terms of the la-ser-induced charge transfer emission from Yb2+ states.

Comparative study on DOTA-derivatized bombesin analog labeled with {sup 90}Y and {sup 177}Lu: in vitro and in vivo evaluation

Energy Technology Data Exchange (ETDEWEB)

Koumarianou, Eftychia [Institute R-RP, NCSR ' Demokritos' , Athens (Greece); IAE, Radioisotope Centre POLATOM, 05-400 Swierk-Otwock (Poland)], E-mail: eytyxiak@yahoo.com; Mikolajczak, Renata; Pawlak, Dariusz [IAE, Radioisotope Centre POLATOM, 05-400 Swierk-Otwock (Poland); Zikos, Xhristos; Bouziotis, Pinelopi [Institute R-RP, NCSR ' Demokritos' , Athens (Greece); Garnuszek, Piotr; Karczmarczyk, Urszula; Maurin, Michal [Department of Radiopharmaceuticals, National Medicines Institute, Chelmska 30/34, 00-725 Warsaw (Poland); Archimandritis, Spyridon C. [Institute R-RP, NCSR ' Demokritos' , Athens (Greece)

2009-08-15

Introduction: The aim of the study was to compare in vitro and in vivo a novel DOTA-chelated bombesin (BN) analog of the amino acid sequence, QRLGNQWAVGHLM-CONH{sub 2} (BN[2-14]NH{sub 2}), labeled with {sup 90}Y and {sup 177}Lu, for its potential use in targeted radiotherapy of tumors expressing gastrin releasing peptide (GRP) receptors. The same amino acid sequence, but with different chelator, referred as BN1.1 (Gly-Gly-Cys-Aca-QRLGNQWAVGHLM-CONH{sub 2}), has already been studied and reported; however, the DOTA-chelated one, suitable for labeling with M{sup +3} type radiometals, was not yet described. Methods: The conditions for labeling of DOTA-BN[2-14]NH{sub 2} with noncarrier added {sup 90}Y and with {sup 177}Lu [specific activity (SA), 15 Ci/mg Lu] were investigated and optimized to provide {sup 90}Y-DOTA-BN[2-14]NH{sub 2} and {sup 177}Lu-DOTA-BN[2-14]NH{sub 2} of high SA. The stability of the radiolabeled compounds in human serum was evaluated over a period of 24 h. The human prostate cancer cell line PC-3, known to express GRP receptors, was used for in vitro evaluation of radiolabeled peptide affinity to GRP receptors and for assessment of cytotoxicity of both nonlabeled and radiolabeled peptide. Biodistribution accompanied by receptor blocking was studied in normal Swiss mice. Results: {sup 90}Y-DOTA-BN[2-14]NH{sub 2} and {sup 177}Lu-DOTA-BN[2-14]NH{sub 2} were obtained with radiochemical yield >98% and high SA (67.3 GBq {sup 90}Y/{mu}mol and 33.6 GBq {sup 177}Lu/{mu}mol, respectively). They were stable when incubated in human serum for up to 24 h. The binding affinities of DOTA-BN[2-14]NH{sub 2} and both {sup nat}Y- and {sup nat}Lu-labeled analogs to GRP receptors were high (IC{sub 50}=1.78, 1.99, and 1.34 nM, respectively), especially for the {sup nat}Lu-DOTA-BN[2-14]NH{sub 2} complex. The cytotoxicity study of DOTA-BN[2-14]NH{sub 2} to PC-3 cells revealed an IC{sub 50}=6300 nM after 72 h of exposition, while the labeled derivatives showed no

Phase formation and stability of quasicrystal/α-Mg interfaces in the Mg–Cd–Yb system

International Nuclear Information System (INIS)

Ohhashi, S.; Suzuki, K.; Kato, A.; Tsai, A.P.

2014-01-01

Phase formation involving icosahedral quasicrystals (iQc) in the Mg–Cd–Yb system was investigated. The phase diagrams obtained revealed that the iQc is in equilibrium with either (Mg, Cd) 2 Yb or an α-Mg phase over a wide composition range at 673 K. A eutectic reaction, where the melt decomposed to a rod-like lamella structure consisting of iQc and α-Mg phases was observed for Mg 68 Cd 24 Yb 8 at 735 K. High-angle annular dark-field scanning transmission microscopy observation of the iQc in Mg 96 Cd 3 Yb 1 verified the atomic positions of the Yb icosahedra and confirmed that the i-MgCdYb is isostructural to the i-CdYb. The formation of the eutectic structure is responsible for the high stability of the iQc/α-Mg interfaces because of good lattice matching; which is coincident interplanar spacing over several planes for the two phases. This coincidence in interplanar spacing was further confirmed in the real atomic structure, for which the twofold planes of the iQc, and the [0 0 0 2] and [2 −1 −1 0] planes of α-Mg are dominant factors in determining the stability of the interfaces

Near-infrared quantum cutting in Yb3+ ion doped strontium vanadate

Science.gov (United States)

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

2016-05-01

The materials Sr3-x(VO4)2:xYb were successfully synthesized by co-precipitation method varying the concentration of Yb3+ ions from 0 to 0.06 mol. It was characterize by powder X-ray powder diffraction (XRD) and surface morphology was studied by scanning electronic microscope (SEM). The photoluminescence (PL) properties were studied by spectrophotometers in near infra red (NIR) and ultra violet visible (UV-VIS) region. The Yb3+ ion doped tristrontium vanadate (Sr3(VO4)2) phosphors that can convert a photon of UV region (349 nm) into photons of NIR region (978, 996 and 1026 nm). Hence this phosphor could be used as a quantum cutting (QC) luminescent convertor in front of crystalline silicon solar cell (c-Si) panels to reduce thermalization loss due to spectral mismatch of the solar cells. The theoretical value of quantum efficiency (QE) was calculated from steady time decay measurement and the maximum efficiency approached up to 144.43%. The Sr(3-x) (VO4)2:xYb can be potentiality used for betterment of photovoltaic (PV) technology.

Up-conversion mechanisms in Er{sup 3+} doped YbAG crystals

Energy Technology Data Exchange (ETDEWEB)

Kaczkan, Marcin; Borowska, Maja [Institute of Microelectronics and Optoelectronics PW, Warsaw (Poland); Malinowski, Michal [Institute of Microelectronics and Optoelectronics PW, Warsaw (Poland); Institute of Electronic Materials Technology, Warsaw (Poland); Lukasiewicz, Tadeusz; Kolodziejak, Katarzyna [Institute of Electronic Materials Technology, Warsaw (Poland)

2009-07-15

Up-conversion phenomena leading to the red, green and violet emissions in erbium doped ytterbium-aluminum garnet (YbAG) are investigated. Absorption and emission spectra and luminescence dynamics from various excited states of YbAG:Er{sup 3+} were registered. The low temperature absorption spectra were used to determine Stark levels energies of Er{sup 3+} ion in the investigated host. Emissions from the high lying excited states {sup 2}G{sub 9/2}, {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} of Er{sup 3+} were characterized under pulsed multi-photon IR excitation in the region of wavelength corresponding to the strong {sup 2}F{sub 7/2} {yields} {sup 2}F{sub 5/2} absorption transition of Yb{sup 3+} ions. Using the rate equations formalism the dynamics of the observed emissions were modeled. From the comparison of the measured and calculated decays the energy transfer rates between Yb{sup 3+} and Er{sup 3+} ions were evaluated. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Synthesis and Downconversion Emission Property of Yb2O3:Eu3+ Nanosheets and Nanotubes

Directory of Open Access Journals (Sweden)

Chao Qian

2013-01-01

Full Text Available Ytterbium oxide (Yb2O3 nanocrystals with different Eu3+ (1%, 2%, 5%, and 10% doped concentrations were synthesized by a facile hydrothermal method, subsequently by calcination at 700°C. The crystal phase, size, and morphology of prepared samples were characterized by X-ray diffraction (XRD and transmission electron microscopy (TEM. The results show that the as-prepared Yb2O3 nanocrystals with sheet- and tube-like shape have cubic phase structure. The Eu3+ doped Yb2O3 nanocrystals were revealed to have good down conversion (DC property and intensity of the DC luminescence can be modified by Eu3+ contents. In our experiment the 1% Eu3+ doped Yb2O3 nanocrystals showed the strongest DC luminescence among the obtained Yb2O3 nanocrystals.

Evidence for inelastic neutron acceleration by the 177Lu isomer

International Nuclear Information System (INIS)

Roig, O.; Belier, G.; Meot, V.; Daugas, J.-M.; Abt, D.; Aupiais, J.; Jutier, Ch.; Petit, G. Le; Letourneau, A.; Marie, F.; Veyssiere, Ch.

2006-01-01

The neutron burnup cross section σ burnup m on the long-lived metastable state of 177 Lu has been measured from a specially designed isomeric target. The Maxwellian averaged cross section obtained for this reaction on 177 Lu m (J π =23/2 - ) is σ burnup m =626±45 b at the reactor temperature T=323 K. The difference between the burnup cross section and the previously measured capture cross section σ n,γ clearly shows a possible existence of 177 Lu m deexcitation via (n,n ' ) inelastic neutron acceleration channels. The results are interpreted in terms of a statistical approach using parameters from a deformed optical potential calculation

Indium-modified Yb:KLu(WO{sub 4}){sub 2} crystal: Growth, spectroscopy and laser operation

Energy Technology Data Exchange (ETDEWEB)

Serres, J.M. [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcellí Domingo, s/n., Tarragona E-43007 (Spain); Mateos, X., E-mail: xavier.mateos@urv.cat [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcellí Domingo, s/n., Tarragona E-43007 (Spain); Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 2A Max-Born-Str., Berlin D-12489 (Germany); Loiko, P. [ITMO University, 49 Kronverkskiy pr., St. Petersburg 197101 (Russian Federation); Griebner, U.; Petrov, V. [Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 2A Max-Born-Str., Berlin D-12489 (Germany); Yumashev, K. [Center for Optical Materials and Technologies (COMT), Belarusian National Technical University, 65/17 Nezavisimosti Ave., Minsk 220013 (Belarus); Aguiló, M.; Díaz, F. [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcellí Domingo, s/n., Tarragona E-43007 (Spain)

2017-03-15

We report on the growth, spectroscopic and laser characterization of a novel monoclinic laser crystal, Yb,In:KLu(WO{sub 4}){sub 2} (Yb,In:KLuW). The absorption, stimulated-emission and gain cross-section spectra of 3.5 at% Yb, 5.5 at% In-doped KLuW are determined at room temperature with polarized light and compared with those for Yb,In:KYW, as well as singly Yb-doped KLuW and KYW crystals. It is found that the introduction of In results in a decrease of the transition cross-sections and in a spectral broadening of the absorption and emission bands. Such a broadening is more pronounced for light polarization E ||N{sub p}. For Yb,In:KLuW, the maximum σ{sub abs} is 9.9×10{sup –20} cm{sup 2} at 980.9 nm for E ||N{sub m} and the corresponding bandwidth of the absorption peak is 3.7 nm. The radiative lifetime for Yb{sup 3+} ions is 237±5 µs. The stimulated-emission cross-sections are σ{sub SE}(m)=2.4×10{sup –20} cm{sup 2} at 1022.4 nm and σ{sub SE}(p)=1.3×10{sup –20} cm{sup 2} at 1039.1 nm corresponding to an emission bandwidth of >30 nm and >35 nm, respectively. The diode-pumped N{sub g}-cut Yb,In:KLuW microchip laser generated 4.11 W at 1042–1048 nm with a slope efficiency of 78%. The Yb,In:KLuW crystal is very promising for the generation of sub-100 fs pulses in mode-locked lasers due to its broadband emission characteristics.

Targeting angiogenesis for radioimmunotherapy with a {sup 177}Lu-labeled antibody

Energy Technology Data Exchange (ETDEWEB)