Spectral variations and energy transfer processes on both Er 3+ ion concentration and excitation densities in Yb 3+-Er 3+ codoped LaF3 materials

International Nuclear Information System (INIS)

Zhang Jisen; Qin Weiping; Zhao Dan; Degejihu; Zhang Jishuang; Wang Yan; Cao Chunyan

2007-01-01

In comparison with the up-conversion spectra of Yb 3+ -Er 3+ codopded systems reported previously, the interesting intensity changes of up-conversion luminescence between the violet, the blue, the green and the red on the both Er 3+ ion concentration and excitation density with 978 nm laser diodes as an excitation source were observed in Yb 3+ -Er 3+ codopded LaF 3 powders. In order to clarify the change mechanisms, the up-conversion spectra of LaF 3 : 10 mol% Yb 3+ , 0.5 mol% Er 3+ and LaF 3 : 10 mol% Yb 3+ , 1 mol% Er 3+ were investigated and the results indicated that the cross-relaxation processes between Er 3+ ions and the thermal population of the 2 H 11/2 level play significant roles

Polarized spectroscopic properties of Er{sup 3+}:Gd{sub 2}SiO{sub 5} crystal and evaluation of Er{sup 3+}:Yb{sup 3+}:Gd{sub 2}SiO{sub 5} crystal as a 1.55 μm laser medium

Energy Technology Data Exchange (ETDEWEB)

Wang, H. [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Huang, J.H.; Gong, X.H.; Chen, Y.J.; Lin, Y.F.; Luo, Z.D. [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Huang, Y.D., E-mail: huyd@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2016-10-01

An Er{sup 3+}-doped Gd{sub 2}SiO{sub 5} single crystal with high optical quality has been grown by the Czochralski method. Polarized absorption and fluorescence spectra and fluorescence lifetime of the crystal were measured at room temperature. Intensity parameters, spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes were estimated on the basis of the Judd–Ofelt theory. Besides, potentiality of 1.55 μm laser emission in an Er{sup 3+}–Yb{sup 3+} co-doped Gd{sub 2}SiO{sub 5} crystal was evaluated.

Hydrothermal-precipitation preparation of CdS@(Er3+:Y3Al5O12/ZrO2) coated composite and sonocatalytic degradation of caffeine.

Science.gov (United States)

Huang, Yingying; Wang, Guowei; Zhang, Hongbo; Li, Guanshu; Fang, Dawei; Wang, Jun; Song, Youtao

2017-07-01

Here, we reported a novel method to dispose caffeine by means of ultrasound irradiation combinated with CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) coated composite as sonocatalyst. The CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) was synthesized via hydrothermal-precipitation method and then characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and UV-vis diffuse reflectance spectra (DRS). After that, the sonocatalytic degradation of caffeine in aqueous solution was conducted adopting CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) and CdS@ZrO 2 coated composites as sonocatalysts. In addition, some influencing factors such as CdS and ZrO 2 molar proportion, caffeine concentration, ultrasonic irradiation time, sonocatalyst dosage and addition of several inorganic oxidants on sonocatalytic degradation of caffeine were investigated by using UV-vis spectra and gas chromatograph. The experimental results showed that the presence of Er 3+ :Y 3 Al 5 O 12 could effectively improve the sonocatalytic degradation activity of CdS@ZrO 2 . To a certain extent some inorganic oxidants can also enhance sonocatalytic degradation of caffeine in the presence of CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ). The best sonocatalytic degradation ratio (94.00%) of caffeine could be obtained when the conditions of 5.00mg/L caffeine, 1.00g/L prepared CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ), 10.00mmol/LK 2 S 2 O 8 , 180min ultrasonic irradiation (40kHz frequency and 50W output power), 100mL total volume and 25-28°C temperature were adopted. It seems that the method of sonocatalytic degradation caused by CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) displayspotentialadvantages in disposing caffeine. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, Characterization and Sonocatalytic Activity of Co/N/Er3+ : Y3Al5O12 /TiO2 Film for the Degradation of Organic Dyes

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Wang L.

2015-07-01

Full Text Available The sonocatalytic degradation of organic dyes (C.I. 50040, C.I. Reactive Red 1, C.I. Acid Orange 7 catalysed by Co/N/Er3+ : Y3Al5O12/TiO2 films was studied. For the preparation of Co/N/Er3+ : Y3Al5O12/TiO2 films, the sol-gel coating process was used. The phase composition, morphology, precursor at different temperatures and emitting light properties of the calcined powders were analysed by X-ray diffraction (XRD, absorption spectra and upconversion emission spectra. The X-ray diffraction of powder samples of Co/N/Er3+ : Y3Al5O12/TiO2 took on anatase mine peaks and upconversion luminous agent, respectively. Analysis of absorption spectra of amorphous Co/N/Er3+ : Y3Al5O12/TiO2 showed that doping N stretching vibration peak of water or hydroxyl adsorption, Co2+ ion had very strong absorption in 1.0–1.7 μm wavelength range, the transition luminescence of Er3+ ions was just on Co2+ ions absorption band. The emission spectrum indicated that Co/N/Er3+ : Y3Al5O12/TiO2 could launch green 500–560 nm and red 650–700 nm, 525, 550 and 660 nm peaks corresponding to 2H11/2, 4S3/2 → 4I15/2 and 4H9/2 → 4I15/2 transition of Er3+. Doping Co and N enhanced the upconversion luminescence and absorption effect. Sonocatalytic degradation effect of organic dyes loading Co/N/Er3+ : Y3Al5O12/TiO2 was better when ultrasonic intensity was equal to 15 W cm–2. The degradation ratios of aqueous solutions of these three kinds of organic dyes by ultrasonic irradiation were obviously lower than by ultrasonic irradiation together with Co/N/Er3+ : Y3Al5O12/TiO2 films in the same conditions. Degradation kinetics of organic dyes by ultrasonic irradiation and by ultrasonic irradiation cooperating with Co/N/Er3+ : Y3Al5O12/TiO2 films followed the first-order reaction.

Preparation of Er"3"+:Y_3Al_5O_1_2/KNbO_3 composite and application in innocent treatment of ketamine by using sonocatalytic decomposition method

International Nuclear Information System (INIS)

Zhang, Hongbo; Wei, Chunsheng; Huang, Yingying; Li, Guanshu; Wu, Qiong; Wang, Jun; Song, Youtao

2016-01-01

Highlights: • Upconversion luminescence agent Er:YAG can enhance sonocatalytic activity of KNbO_3. • Harmless of narcotic drugs was achieved through sonocatalytic destruction. • Possible sonocatalytic destruction mechanism on narcotic drugs was proposed. - Abstract: A novel sonocatalyst, Er"3"+:Y_3Al_5O_1_2/KNbO_3 composite, was synthesized, and then, characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). In order to evaluate the sonocatalytic activity of prepared Er"3"+:Y_3Al_5O_1_2/KNbO_3 composite, the sonocatalytic degradation of ketamine, a kind of narcotic drug, was studied. In addition, some influencing factors such as mass ratio, heat-treated temperature and heat-treated time on the sonocatalytic activity of prepared Er"3"+:Y_3Al_5O_1_2/KNbO_3 powders and ultrasonic irradiation time on the sonocatalytic degradation of ketamine were examined by using GC–MS machine. The experimental results showed that the Er"3"+:Y_3Al_5O_1_2/KNbO_3 composite is a good sonocatalyst in the field of ultrasonic chemistry and the sonocatalytic degradation was an effective method for the innocent treatment of ketamine.

SGK3 Sensitivity of Voltage Gated K+ Channel Kv1.5 (KCNA5

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Musaab Ahmed

2016-01-01

Full Text Available Background: The serum & glucocorticoid inducible kinase isoform SGK3 is a powerful regulator of several transporters, ion channels and the Na+/K+ ATPase. Targets of SGK3 include the ubiquitin ligase Nedd4-2, which is in turn a known regulator of the voltage gated K+ channel Kv1.5 (KCNA5. The present study thus explored whether SGK3 modifies the activity of the voltage gated K+ channel KCNA5, which participates in the regulation of diverse functions including atrial cardiac action potential, activity of vascular smooth muscle cells, insulin release and tumour cell proliferation. Methods: cRNA encoding KCNA5 was injected into Xenopus oocytes with and without additional injection of cRNA encoding wild-type SGK3, constitutively active S419DSGK3, inactive K191NSGK3 and/or wild type Nedd4-2. Voltage gated K+ channel activity was quantified utilizing dual electrode voltage clamp. Results: Voltage gated current in KCNA5 expressing Xenopus oocytes was significantly enhanced by wild-type SGK3 and S419DSGK3, but not by K191NSGK3. SGK3 was effective in the presence of ouabain (1 mM and thus did not require Na+/K+ ATPase activity. Coexpression of Nedd4-2 decreased the voltage gated current in KCNA5 expressing Xenopus oocytes, an effect largely reversed by additional coexpression of SGK3. Conclusion: SGK3 is a positive regulator of KCNA5, which is at least partially effective by abrogating the effect of Nedd4-2.

A broadband-sensitive upconverter La(Ga{sub 0.5}Sc{sub 0.5})O{sub 3}:Er,Ni,Nb for crystalline silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Mizuno, Shintaro; Luitel, Hom Nath; Tani, Toshihiko [Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

2016-01-25

We have developed an upconverter that significantly broadens the sensitive range, to overcome the shortcoming that conventional Er{sup 3+}-doped upconverters used for crystalline silicon solar cells can utilize only a small portion of the solar spectrum at around 1.55 μm. We have designed the combination of the sensitizers and host material to utilize photons not absorbed by silicon or Er{sup 3+} ions. Ni{sup 2+} ions have been selected as the sensitizers that absorb photons in the wavelength range between the silicon absorption edge (1.1 μm) and the Er{sup 3+} absorption band and transfer the energies to the Er{sup 3+} emitters, with La(Ga,Sc)O{sub 3} as the host material. The Ga to Sc ratio has been optimized to tune the location of the Ni{sup 2+} absorption band for sufficient energy transfer. Co-doping with Nb{sup 5+} ions is needed for charge balance to introduce divalent Ni{sup 2+} ions into the trivalent Ga{sup 3+} and Sc{sup 3+} sites. In addition to 1.45–1.58 μm photons directly absorbed by the Er{sup 3+} ions, we have demonstrated upconversion of 1.1–1.35 μm photons in the Ni{sup 2+} absorption band to 0.98 μm photons, using 10% Er, 0.5% Ni, and 0.5% Nb-doped La(Ga{sub 0.5}Sc{sub 0.5})O{sub 3}. The broadband-sensitive upconverter developed here can improve conversion efficiency of crystalline silicon solar cells more notably than conventional ones.

Laser-induced, Er3+ trace-sensitized red-to-blue photon avalanche up-conversion in Tm3+-doped LiKYF5 crystals

International Nuclear Information System (INIS)

Jouart, J P; Bouffard, M; Boulma, E; Diaf, M; Vojtenko, E N; Khaidukov, N M

2005-01-01

The results for a spectroscopic study demonstrating that the excited-state absorption(ESA) of Tm 3+ :LiKYF 5 at 648nm is dependent on the purity of starting materials used for synthesizing the crystal are presented. The Er 3+ -free LiKYF 5 crystal doped with Tm 3+ is transparent at 648 nm because the majority of the Tm 3+ ions are in the ground 3 H 6 state whatever the selective excitation intensity, whereas the Er 3+ -contaminated crystal is semi-transparent. In the second case a small increase of the excitation intensity above a certain threshold produces an abrupt enhancement of the ESA process at 648 nm as well as the blue and the green emissions that are detected. All three processes, namely ESA corresponding to the 3 F 4 (2) → 1 G 4 (2) Tm 3+ transition, the blue emission due to the 1 G 4 → 3 H 6 Tm 3+ transition and the green emission from the 4 S 3/2 Er 3+ level, are sensitized with the Tm 3+ → Er 3+ → Tm 3+ energy transfers which promote the conversion of Tm 3+ ions from the 1 G 4 and the 3 H 4 states to the metastable 3 F 4 state

Spectroscopic properties of Er3+/Yb3+ Co-doped zinc boro-tellurite glasses for 1.5 xB5m broadband optical amplifiers

Science.gov (United States)

Suthanthirakumar, P.; Karthikeyan, P.; Vijayakumar, R.; Marimuthu, K.

2015-06-01

A new series of Er3+/Yb3+ co-doped Zinc boro-tellurite glasses with the chemical composition (40-x-y)B2O3+ 25TeO2+20ZnO+15BaO+xYb2O3+yEr2O3 (where x = 0.1, 0.5, 1 and 3; y =1 in wt %) were prepared by melt quenching technique and their spectroscopic behavior were studied through UV-Vis-NIR absorption and NIR luminescence measurements. The bonding parameters (β ¯ and δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ=2, 4 and 6) have been calculated from the band positions of the absorption spectra. A broad near-infrared emission band at 1540 nm with a full width at half maximum around 80 nm was observed from the NIR luminescence spectra by monitoring an excitation at 980 nm. The absorption cross-section and emission cross-section for the4I13/2→4I15/2 transition of the Er3+ ions were also determined using McCumber theory and the results were discussed and reported.

2.05 xB5m emission properties and energy transfer mechanism of germanate glass doped with Ho3+, Tm3+, and Er3+

Science.gov (United States)

Xu, Rongrong; Wang, Meng; Tian, Ying; Hu, Lili; Zhang, Junjie

2011-03-01

A new GeO2-Ga2O3-Na2O-BaO-La2O3 germanate glass doped with Ho2O3, Tm2O3, and Er2O3 has been investigated for application as a laser material at the 2 μm region. The spectroscopic properties and energy transfer mechanisms of Ho3+ sensitized by Tm3+ and Er3+ are analyzed. Based on the measurement of absorption spectra, the Judd-Ofelt intensity parameters, radiation emission probability, branching ratio, and lifetime of Ho3+ are calculated to evaluate the spectroscopic properties. The maximum value of emission cross section of Ho3+ around 2.05 μm is 8.003×10-21 cm2, which indicates that the germanate glass may provide high gain as a good medium in high-power level laser system. It is also found that the 2.05 μm emission of Ho3+:5I7→5I8 can be greatly enhanced by adding the proper amount of Er2O3 and Tm2O3 under excitation at 808 nm. With the large energy transfer coefficient, the high efficient energy transfer process among Ho3+, Tm3+, and Er3+ ions is proven.

Thermoluminescence and optically stimulated luminescence properties of nanocrystalline Er3+ and Yb3+ doped Y3Al5O12 exposed to β-rays

International Nuclear Information System (INIS)

RodrIguez, R A; Rosa, E de la; Salas, P; Melendrez, R; Barboza-Flores, M

2005-01-01

The thermoluminescence (TL) and optically stimulated luminescence (OSL) characterization of Er 3+ and Yb 3+ doped Y 3 Al 5 O 12 nanocrystalline samples prepared by the precipitation process and exposed to β-rays are discussed. The TL as well as the OSL were two orders of magnitude higher in Er 3+ doped than in Yb 3+ specimens. The charge trapping and the radiative thermally stimulated recombination processes in Y 3 Al 5 O 12 : Er 3+ involve four trapping states at 166, 243, 342 and 424 deg. C, but just two trapping levels at 219 and 413 deg. C for Y 3 Al 5 O 12 : Yb 3+ at a heating rate of 10 deg. C s -1 . The photostimulation with 470 nm light causes in both phosphors a radiative recombination of the optically free charge carriers belonging to the same trapping states. The TL and the OSL as a function of radiation dose behaviour were linear in the 10-100 Gy dose range. The results provide evidence of the potential uses of these materials in radiation storage and dosimeter devices

Synthesis of novel sonocatalyst Er3+:YAlO3/Nb2O5 and its application for sonocatalytic degradation of methamphetamine hydrochloride.

Science.gov (United States)

Wei, Chunsheng; Yi, Kuiyu; Sun, Guangsheng; Wang, Jun

2018-04-01

The composited sonocatalyst Er 3+ :YAlO 3 /Nb 2 O 5 was prepared by ultrasonic dispersion and high temperature calcinations method. The microstructure of Er 3+ :YAlO 3 was prepared via sol-gel method and Nb 2 O 5 was prepared by hydrothermal method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX), ultraviolet-visible (UV-vis) spectra and photoluminescence (PL) spectra, respectively. The sonocatalytic decomposition activity of composite sonocatalyst Er 3+ :YAlO 3 /Nb 2 O 5 was investigated by using ultrasound as sound source and methamphetamine hydrochloride as the target degradation product. The influences of composite sonocatalyst Er 3+ :YAlO 3 /Nb 2 O 5 with different ratios, calcination temperature, ultrasonic power, ultrasonic temperature and recycle times were investigated. The results showed that the sonocatalytic degradation rate was 82.17% after 5 h sonocatalytic decomposition under the condition of ultrasonic power of 700 W, frequency of 45 kHz and surrounding temperature of 30 °C. The sonocatalytic degradation ability of composite sonocatalyst for methamphetamine hydrochloride in aqueous solution was still good after recycled five times. The hydroxyl radicals (OH) and holes (h + ) are identified and hydroxyl radicals (OH) plays a major role during the oxidation process. The experimental results show that sonocatalytic is a new idea for the harmless treatment of amphetamine-type stimulants. Copyright © 2017 Elsevier B.V. All rights reserved.

An N-Terminal ER Export Signal Facilitates the Plasma Membrane Targeting of HCN1 Channels in Photoreceptors.

Science.gov (United States)

Pan, Yuan; Laird, Joseph G; Yamaguchi, David M; Baker, Sheila A

2015-06-01

Hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels are widely expressed in the retina. In photoreceptors, the hyperpolarization-activated current (Ih) carried by HCN1 is important for shaping the light response. It has been shown in multiple systems that trafficking HCN1 channels to specific compartments is key to their function. The localization of HCN1 in photoreceptors is concentrated in the plasma membrane of the inner segment (IS). The mechanisms controlling this localization are not understood. We previously identified a di-arginine endoplasmic reticulum (ER) retention motif that negatively regulates the surface targeting of HCN1. In this study, we sought to identify a forward trafficking signal that could counter the function of the ER retention signal. We studied trafficking of HCN1 and several mutants by imaging their subcellular localization in transgenic X. laevis photoreceptors. Velocity sedimentation was used to assay the assembly state of HCN1 channels. We found the HCN1 N-terminus can redirect a membrane reporter from outer segments (OS) to the plasma membrane of the IS. The sequence necessary for this behavior was mapped to a 20 amino acid region containing a leucine-based ER export motif. The ER export signal is necessary for forward trafficking but not channel oligomerization. Moreover, this ER export signal alone counteracted the di-arginine ER retention signal. We identified an ER export signal in HCN1 that functions with the ER retention signal to maintain equilibrium of HCN1 between the endomembrane system and the plasma membrane.

Influence of Er3+/Yb3+ concentration ratio on the down-conversion and up-conversion luminescence and lifetime in GdVO4:Er3+/Yb3+ microcrystals

Directory of Open Access Journals (Sweden)

Gavrilović T.V.

2015-01-01

Full Text Available In this paper, we studied the effects of Er3+/Yb3+ concentration ratio on structural, morphological and luminescence properties of GdVO4:Er3+/Yb3+ green phosphors prepared by a high-temperature solid state method. The samples with different concentrations (between 0.5 to 2 mol% of dopant Er3+ emitting ions and different concentrations (between 5 to 20 mol% of sensitizer ions (Yb3+ were studied. The phosphors were characterized by the X-ray diffraction (XRD, scanning electron microscopy (SEM and photoluminescence spectroscopy. For all samples, XRD diffraction patterns confirmed a formation of a pure GdVO4 phase, while the SEM showed that the materials are comprised of chunks of deformed particles with an average diameter ranging from approximately 2 μm to 8 μm. Both, down-conversion and up-conversion emission spectra of GdVO4:Er3+/Yb3+ samples, under near UV and IR excitations, exhibit two strong emission bands in the green spectral region at 525 nm and 552 nm wavelengths corresponding to 2H11/2 →4I15/2 and 4S3/2 → 4I15/2 electronic transitions of Er3+ ions. The intensity of the green emission was changed by changing the Er3+/Yb3+ concentration ratio. This dual-mode luminescence makes these materials ideal as green phosphors for a wide variety of applications in the fields of bioanalysis and biomedical. [Projekat Ministarstva nauke Republike Srbije, br. 45020 i br. 172056

Spectral properties of Er3+/Yb3+ codoped tungsten-tellurite glasses.

Science.gov (United States)

Shen, Xiang; Nie, QiuHua; Xu, TieFeng; Gao, Yuan

2005-07-01

The spectral properties of Er3+/Yb3+ codoped tungsten-tellurite (WT) glasses have been investigated. The measured absorption spectra are analyzed by Judd-Ofelt theory. The compositional change of intensity parameter omega2 is attributed to the change in the covalency between the Er3+ and oxygen ions, the asymmetry in the local structures around the Er3+ ions can be neglected. The lifetimes of 4I(13/2) level of Er3+ in WT glasses are measured and comparable with other TeO2-based glasses. The stimulated emission cross-section is calculated based on McCumber theory. The fluorescence full width at half maximum (FWHM) and the emission cross-section (sigma(peak)) of the 4I(13/2) --> 4I(15/2) transition of Er3+ in different glass hosts have been compared. The suitability of such WT glasses as host materials for 1.5 microm broadband amplification is discussed.

Computational modelling of Er(3+): Garnet laser materials

Science.gov (United States)

Spangler, Lee H.

1994-01-01

The Er(3+) ion has attracted a lot of interest for four reasons: (1) Its (4)I(sub 13/2) yields (4)I(sub 15/2) transition lases in the eyesafe region near 1.5 micron; (2) the (4)I(sub 13/2) transition lases near 2.8 micron, an important wavelength for surgical purposes; (3) it displays surprisingly efficient upconversion with lasing observed at 1.7, 1.2, 0.85, 0.56, 0.55, and 0.47 micron following 1.5 micron pumping; and (4) it has absorption bands at 0.96 and 0.81 micron and thus can be diode pumped. However, properties desirable for upconversion reduce the efficiency of 1.5 and 3 micron laser operation and vice versa. Since all of the processes are influenced by the host via the crystal field induced stark splittings in the Er levels, this project undertook modelling of the host influence on the Er lasinng behavior. While growth and measurement of all ten Er(3+) doped garnets is the surest way of identifying hosts which maximize upconversion (or conversly, 1.5 and 3 micron performance), it is also expensive - costing approximately $10,000/material or approximately $100,000 for the materials computationally investigated here. The calculations were performed using a quantum mechanical point charge model developed by Clyde Morrison at Harry Diamond Laboratories. The programs were used to fit the Er:YAG experimental energy levels so that the crystal field parameters, B(sub nm) could be extracted. From these radial factors, rho (sub n) were determined for Er(3+) in garnets. These, in combination with crystal field components, Anm, available from X-ray data, were used to predict energy levels for Er in the other nine garnet hosts. The levels in Er:YAG were fit with an rms error of 12.2/cm over a 22,000/cm range. Predicted levels for two other garnets for which literature values were available had rms errors of less than 17/cm , showing the calculations to be reliable. Based on resonances between pairs of calculated stark levels, the model predicts GSGG as the best host

Preparation of Er{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}/KNbO{sub 3} composite and application in innocent treatment of ketamine by using sonocatalytic decomposition method

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hongbo [College of Chemistry, Liaoning University, Shenyang 110036 (China); Wei, Chunsheng [College of Chemistry, Liaoning University, Shenyang 110036 (China); National Police University of China, Shenyang 110854 (China); Huang, Yingying [College of Chemistry, Liaoning University, Shenyang 110036 (China); Li, Guanshu [College of Environment, Liaoning University, Shenyang 110036 (China); Wu, Qiong [College of Chemistry, Liaoning University, Shenyang 110036 (China); Wang, Jun, E-mail: wangjun888tg@126.com [College of Chemistry, Liaoning University, Shenyang 110036 (China); Song, Youtao [College of Environment, Liaoning University, Shenyang 110036 (China)

2016-11-05

Highlights: • Upconversion luminescence agent Er:YAG can enhance sonocatalytic activity of KNbO{sub 3}. • Harmless of narcotic drugs was achieved through sonocatalytic destruction. • Possible sonocatalytic destruction mechanism on narcotic drugs was proposed. - Abstract: A novel sonocatalyst, Er{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}/KNbO{sub 3} composite, was synthesized, and then, characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). In order to evaluate the sonocatalytic activity of prepared Er{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}/KNbO{sub 3} composite, the sonocatalytic degradation of ketamine, a kind of narcotic drug, was studied. In addition, some influencing factors such as mass ratio, heat-treated temperature and heat-treated time on the sonocatalytic activity of prepared Er{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}/KNbO{sub 3} powders and ultrasonic irradiation time on the sonocatalytic degradation of ketamine were examined by using GC–MS machine. The experimental results showed that the Er{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}/KNbO{sub 3} composite is a good sonocatalyst in the field of ultrasonic chemistry and the sonocatalytic degradation was an effective method for the innocent treatment of ketamine.

Continuously tunable cw lasing near 2.75 μm in diode-pumped Er3+ : SrF2 and Er3+ : CaF2 crystals

International Nuclear Information System (INIS)

Basiev, Tasoltan T; Orlovskii, Yu V; Polyachenkova, M V; Fedorov, Pavel P; Kuznetsov, S V; Konyushkin, V A; Osiko, Vyacheslav V; Alimov, Olimkhon K; Dergachev, Alexey Yu

2006-01-01

CW lasing is obtained in Er 3+ (5%) : CaF 2 and Er 3+ (5%) : SrF 2 crystals near 2.75 μm with 0.4 and 2 W of output powers, respectively, upon transverse diode laser pumping into the upper 4 I 11/2 laser level of erbium ions at 980 nm. Continuous tuning of the laser wavelength between 2720 and 2760 nm is realised in the Er 3+ : SrF 2 crystal. (special issue devoted to the 90th anniversary of a.m. prokhorov)

The anisotropic magnetic property and Faraday rotation in Er3Ga5O12 under high magnetic field

International Nuclear Information System (INIS)

Wang Wei; Zhang Xijuan; Liu Gongqiang

2005-01-01

A theoretical investigation on the anisotropic magnetic property and Faraday rotation in Er 3 Ga 5 O 12 (ErGaG) is presented. With particular consideration of the anisotropy of the exchange interaction between rare-earth ions (Er 3+ ), the magnetization, based on the quantum theory, in ErGaG under high magnetic field (HMF) is calculated. Theoretical calculations show that the appropriate choice of the crystal field (CF) parameters is of great importance. A novel three-level model is presented, and in terms of this model the Faraday rotation under HMF is calculated. In addition, it is demonstrated that the Faraday rotation (θ) depends not only on the magnetization (M) but also on the magnetic field (H e ). The theory is in good agreement with the experiment

Photoluminescence quenching by OH in Er- and Pr-doped glasses for 1.5 and 1.3 μm optical amplifiers

Science.gov (United States)

Faber, Anne J.; Simons, Dennis R.; Yan, Yingchao; de Waal, Henk

1994-09-01

In this paper we report on the effect of hydroxyl (OH) groups on the photoluminescence in the near IR (1.5 and 1.3 micrometers ) in rare earth (Er, Pr)-doped glasses. The 1.5 micrometers emission of Er-doped phosphate glasses was studied, before and after a special heat treatment. The luminescent lifetime of the 1.5 micrometers emission increases substantially, typically from 3 ms up to 7.2 ms for a 2 mole% Er2O3-doped phosphate glass, due to the controlled heat treatment. The increase in lifetime is ascribed to a decrease in OH- concentration, which is confirmed by IR-absorption spectroscopy. The quenching by OH is described by a simplified quenching model, which predicts the 1.5 micrometers emission lifetime as a function of Er- concentration with the OH-concentration as parameter. It appears that the larger part of the OH groups is coupled to Er ions and thus acts as quenching center. Photoluminescence quenching by OH groups is also reported for the 1.3 micrometers emission of Pr in GeS2-glasses: In pure OH-free GeS2 glass the 1.3 micrometers emission lifetime is as high as 350 microsecond(s) , for a 400 ppm dopant level. In GeS2 glasses containing only small amounts of OH (approximately 100 ppm), this lifetime is less than 200 microsecond(s) . Both examples demonstrate that for the fabrication of efficient glass optical amplifiers at the telecommunication windows 1.3 and 1.5 micrometers , the OH-impurity level of the host glass must be kept as low as possible.

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

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.

Effect of Er3+ Concentration on Upconversion in Hexagonal-Phase NaYF4:Er3+ Nanocrystals

International Nuclear Information System (INIS)

Luo, X J; Yuminami, R; Sakurai, T; Akimoto, K

2013-01-01

A facile synthesis method was developed to produce hexagonal-phase of NaYF 4 nanocrystals (NCs) doped with Er 3+ in different concentration, which showed upconversion (UC) emission from infrared to visible spectral region. This proposed method is simple and less toxic compared with generally used method so far. It was found that up-conversion emission spectra of NaYF 4 :Er 3+ NCs, excited at 1550 nm, included four peaks at about 980 nm, 800 nm, 660 nm and 540 nm. The effect of Er 3+ concentration on UC in β-phase NaYF 4 :Er 3+ NCs were discussed based on the excitation power dependence. The optimum Er 3+ concentration for 2-step and 3-step UC was found to be around 10∼30%.

Absorption intensities and emission cross sections of principal intermanifold and inter-Stark transitions of Er3+(4f 11) in polycrystalline ceramic garnet Y3Al5O12

International Nuclear Information System (INIS)

Sardar, Dhiraj K.; Russell, Charles C. III; Gruber, John B.; Allik, Toomas H.

2005-01-01

A comparative spectroscopic study is performed on Er 3+ (4f 11 ) ions doped in polycrystalline ceramic garnet Y 3 Al 5 O 12 (YAG) and single-crystal laser rod, both containing nominal 50 at. % of Er 3+ . The standard Judd-Ofelt (JO) model is applied to the room-temperature absorption intensities of Er 3+ (4f 11 ) transitions in both hosts to obtain the phenomenological intensity parameters. These parameters are subsequently used to determine the radiative decay rates, radiative lifetimes, and branching ratios of the Er 3+ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds 2S+1 L J of Er 3+ (4f 11 ) in these garnet hosts. The emission cross sections of the intermanifold Er 3+ 4 I 13/2 → 4 I 15/2 (1.5 μm) transition as well as the principal inter-Stark transition Y 1 →Z 4 (1550 nm) within the corresponding multiplet manifolds have been determined. The room-temperature fluorescence lifetimes of the 4 I 13/2 → 4 I 15/2 (1.5 μm) transition in both polycrystalline ceramic and single-crystal YAG samples were measured. From the radiative lifetimes determined from the JO model and the measured fluorescence lifetimes, the quantum efficiencies for both samples were determined. The comparative study of Er 3+ (4f 11 ) ions performed suggests that polycrystalline ceramic YAG is an excellent alternative to single-crystal YAG rod for certain applications

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

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Xiangtan Li

2014-01-01

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

RBMK fuel channel blockage analysis by MCNP5, DRAGON and RELAP5-3D codes

International Nuclear Information System (INIS)

Parisi, C.; D'Auria, F.

2007-01-01

The aim of this work was to perform precise criticality analyses by Monte-Carlo code MCNP5 for a Fuel Channel (FC) flow blockage accident, considering as calculation domain a single FC and a 3x3 lattice of RBMK cells. Boundary conditions for MCNP5 input were derived by a previous transient calculation by state-of-the-art codes HELIOS/RELAP5-3D. In a preliminary phase, suitable MCNP5 models of a single cell and of a small lattice of RBMK cells were set-up; criticality analyses were performed at reference conditions for 2.0% and 2.4% enriched fuel. These analyses were compared with results obtained by University of Pisa (UNIPI) using deterministic transport code DRAGON and with results obtained by NIKIET Institute using MCNP4C. Then, the changes of the main physical parameters (e.g. fuel and water/steam temperature, water density, graphite temperature) at different time intervals of the FC blockage transient were evaluated by a RELAP5-3D calculation. This information was used to set up further MCNP5 inputs. Criticality analyses were performed for different systems (single channel and lattice) at those transient' states, obtaining global criticality versus transient time. Finally the weight of each parameter's change (fuel overheating and channel voiding) on global criticality was assessed. The results showed that reactivity of a blocked FC is always negative; nevertheless, when considering the effect of neighboring channels, the global reactivity trend reverts, becoming slightly positive or not changing at all, depending in inverse relation to the fuel enrichment. (author)

Optical properties of highly Er{sup 3+}-doped sodium-aluminium-phosphate glasses for broadband 1.5 {mu}m emission

Energy Technology Data Exchange (ETDEWEB)

Reddy, A. Amarnath [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Babu, S. Surendra [Laser Instrumentation Design Centre, Instrument Research and Development Establishment, Dehradun 248008 (India); Pradeesh, K. [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Otton, C.J. [Valencia Nanophotonics Technology Center, Universidad Politecnica de Valencia, 46022 Valencia (Spain); Vijaya Prakash, G., E-mail: prakash@physics.iitd.ac.in [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India)

2011-03-03

Research highlights: > Highly Er{sup 3+} doped phosphate glasses for the 1.54 {mu}m laser emission were explored. > Emission from these doped glasses shows larger lifetimes and quantum efficiencies. > Optical amplifier parameters are greater than other reported phosphate glasses. > The durability and obtained results are most favourable for short-length amplifiers. - Abstract: Erbium-doped Na{sub 3}Al{sub 2}P{sub 3}O{sub 12} (NAP) glasses with compositions 92NAP-(8-x)Al{sub 2}O{sub 3}-(x)Er{sub 2}O{sub 3} (where x = 2-8) were prepared and characterized for absorption, visible and NIR emission and decay time properties. Judd-Ofelt analysis has been carried out to predict radiative properties of luminescent levels of Er{sup 3+} ions. Comparatively larger photoluminescence lifetimes (7.86 ms) and larger quantum efficiencies (74%) for the laser transition, {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} (at 1.54 {mu}m) are observed. The moisture insensitivity, large Er{sup 3+} ion doping capability and relatively high-gain and broad emission at 1.5 {mu}m are the most notable features of these glasses to realize efficient short-length optical amplifiers.

Bursting Events in Pressure Flushing with Expanding Bottom Outlet Channel within Dam Reservoir

Directory of Open Access Journals (Sweden)

soheila Tofighi

2017-01-01

each experiment, the bed level of scouring was measured using laser meters, and the volume of flushing cone was calculated by Surfer software. For investigation of turbulence parameters, the measurement of flow velocity in 0.5cm from the bed of flushing cone in the central axis of the outlet channel in the flow rate of 3 liters per second and water level of 47.5cm for three expansion sizes of the outlet channel (10, 20, and 30cm was performed. The flow velocity measurement was done using an Acoustic Doppler Velocimeter. This device is capable of measuring instantaneous velocity in three directions. Results and Discussion: The results indicated that the relative amount of bottom outlet channel expansion for 0.5, 1 and 1.5 times height of the sediments in the reservoir, leads to increase in flushing cone length for an average of 48, 83 and 113% and flushing cone volume for the average amount of 50, 74 and 96% compared to the case when the outlet channel is not developed. Also the analysis of the turbulence parameters showed that in the nearest axis to the inlet of the bottom outlet channel in which the maximum depth of flushing cone, the occurrence probability of sweep and ejection are maximum and impact angle of moment force due to these events is minimized. However the dominant event here is ejected which was also observed in laboratory experiments the particles were transferred into the channel as suspended load. By increasing the distance from the inlet opening of the channel the occurrence probability of sweep and ejection are decreased and impact angle of moment force due to these events is increased, but again, these two events are the dominant events in this regions and sweep is more important than ejection, that the observations also verify the particles transferred as bed load in these region. Ultimately, it comes to a region where the probabilities of all four events are the same and where the sediment flushing cone reaches the primary sedimentation level that

Entrance channel dependent light-charged particle emission of the 156Er compound

International Nuclear Information System (INIS)

Liang, J.F.; Bierman, J.D.; Kelly, M.P.; Sonzogni, A.A.; Vandenbosch, R.; van Schagen, J.P.S.

1996-01-01

Light-charged particle decay from the 156 Er compound nucleus, populated by 12 C+ 144 Sm and 60 Ni+ 96 Zr at the same excitation energy, were measured in coincidence with the evaporation residues. The high energy slope of charged particle spectra for the 60 Ni-induced reaction is steeper than for the 12 C-induced reaction. Model calculations including particle evaporation during compound nucleus formation result in good agreement with the data. This suggests that the difference in the charged particle spectra between the two entrance channels is due to a longer formation time in the 60 Ni-induced reaction. 14 refs., 3 figs

Self-diffusion of Er and Hf inpure and HfO2-doped polycrystalline Er2O3

International Nuclear Information System (INIS)

Scheidecker, R.W.

1979-01-01

Using a tracer technique, self-diffusion of Er and Hf was measured over the approximate temperature interval of 1600 to 1970 0 C in pure and HfO 2 -doped polycryatalline Er 2 O 3 . Up to about 10 m/o HfO 2 dopant level, the Er self-diffusion coefficients followed a relationship based on cation vacancies. Above 10 m/o HfO 2 , deviation from this relationship occurred, apparently due to clustering of cation vacancies and oxygen interstitials around the dopant hafnia ion. The activation energy for the self-diffusion of Er in pure Er 2 O 3 was 82.2 Kcal/mole and increased with the HfO 2 dopant level present. Self-diffusion of Hf was measured in pure Er 2 O 3 having two impurity levels, and a separation of the grain boundary. The volume diffusion of Hf showed both extrinsic and intrinsic behavior with the transition temperature increasing with the impurity level present in Er 2 O 3 . The activation energy for Hf volume diffusion in the intrinsic region was high, i.e. 235 -+ 9.5 Kcal/mole. The grain boundary diffusion was apparently extrinsic over the entire temperature interval Very low Hf self diffusion rates were found in both pure and HfO 2 doped Er 2 O 3 compositions. Despite a clustering effect, the HfO 2 dopant increased the Hf volume diffusion coefficients

Thermal-Hydraulic Analysis of Coolant Flow Decrease in Fuel Channels of Smolensk-3 RBMK during GDH Blockage Event

International Nuclear Information System (INIS)

Costa, A. L.; Cherubini, M.; D'Auria, F.; Giannotti, W.; Moskalev, A.

2007-01-01

One of the transients that have received considerable attention in the safety evaluation of RBMK reactors is the partial break of a group distribution header (GDH). The coolant flow rate blockage in one GDH might lead to excessive heat-up of the pressure tubes and can result in multiple fuel channels (FC) ruptures. In this work, the GDH flow blockage transient has been studied considering the Smolensk-3 RBMK NPP (nuclear power plant). In the RBMK, each GDH distributes coolant to 40-43 FC. To investigate the behavior of each FC belonging to the damaged GDH and to have a more realistic trend, one (affected) GDH has been schematised with its forty-two FC, one by one. The calculations were performed using the 0-D NK (neutron kinetic) model of the RELAP5-3.3 stand-alone code. The results show that, during the event, the mass flow rate is disturbed differently according to the power distribution established for each FC in the schematization. The start time of the oscillations in mass flow rate depends strongly on the attributed power to each FC. It was also observed that, during the event, the fuel channels at higher thermal power values tend to undergo first cladding rupture leaving the reactor to scram and safeguarding all the other FCs connected to the affected GDH.

Spectroscopic properties and thermal stability of Er3+ -doped TeO2-B2O3-Nb2O5-ZnO glass for potential WDM amplifier.

Science.gov (United States)

Xu, Tiefeng; Zhang, Xudong; Li, Guangpo; Dai, Shixun; Nie, Qiuhua; Shen, Xiang; Zhang, Xianghua

2007-06-01

A series of novel 70TeO2-(15-x)B2O3-xNb2O5-15ZnO-1wt.% Er2O3 (TBN x=0, 3, 6, 9, 12 and 15 mol%) tellurite glasses were prepared. The thermal stability, absorption spectra, emission spectra, and the lifetime of the (4)I(13/2) level of Er(3+) ions were measured and investigated. Three Judd-Ofelt intensity parameters Omega(t) (t=2, 4 and 6) (Omega(2)=(5.42-6.76)x10(-20)cm(2); Omega(4)=(1.37-1.73)x10(-20)cm(2); Omega(6)=(0.70-0.94)x10(-20)cm(2)) of Er(3+) ions were calculated by Judd-Ofelt theory. It is found that the Omega(6) first increases with the increase of Nb2O5 content from 0 to 6 mol% and then decreases, which is mainly affected by the number of non-bridging oxygen ions of the glass network. The high peak of stimulated emission cross-section (sigma(e)(peak)=(0.77-0.91)x10(-20)cm(2)) of Er(3+): (4)I(13/2)-->(4)I(15/2) transition were obtained according to McCumber theory and broad full width at half maximum (FWHM=65-73 nm) of the (4)I(13/2)-->(4)I(15/2) transition of Er(3+) ions were measured. The results indicate that these new TBN glasses can be used as a candidate host material for potential broadband optical amplifiers.

ER-to-plasma membrane tethering proteins regulate cell signaling and ER morphology.

Science.gov (United States)

Manford, Andrew G; Stefan, Christopher J; Yuan, Helen L; Macgurn, Jason A; Emr, Scott D

2012-12-11

Endoplasmic reticulum-plasma membrane (ER-PM) junctions are conserved structures defined as regions of the ER that tightly associate with the plasma membrane. However, little is known about the mechanisms that tether these organelles together and why such connections are maintained. Using a quantitative proteomic approach, we identified three families of ER-PM tethering proteins in yeast: Ist2 (related to mammalian TMEM16 ion channels), the tricalbins (Tcb1/2/3, orthologs of the extended synaptotagmins), and Scs2 and Scs22 (vesicle-associated membrane protein-associated proteins). Loss of all six tethering proteins results in the separation of the ER from the PM and the accumulation of cytoplasmic ER. Importantly, we find that phosphoinositide signaling is misregulated at the PM, and the unfolded protein response is constitutively activated in the ER in cells lacking ER-PM tether proteins. These results reveal critical roles for ER-PM contacts in cell signaling, organelle morphology, and ER function. Copyright © 2012 Elsevier Inc. All rights reserved.

Laser frequency stabilization at 1.5 microns using ultranarrow inhomogeneous absorption profiles in Er3+:LiYF4

International Nuclear Information System (INIS)

Boettger, Thomas; Pryde, G.J.; Thiel, C.W.; Cone, R.L.

2007-01-01

Single-frequency diode lasers have been frequency stabilized to 1.5 kHz Allan deviation over 0.05-50 s integration times, with laser frequency drift reduced to less than 1.4 kHz/min, using the frequency reference provided by an ultranarrow inhomogeneously broadened Er 3+ : 4 I 15/2 →4 I 13/2 optical absorption transition at a vacuum wavelength of 1530.40 nm in a low-strain LiYF 4 crystal. The 130 MHz full-width at half-maximum (FWHM) inhomogeneous line width of this reference transition is the narrowest reported for a solid at 1.5 μm. Strain-induced inhomogeneous broadening was reduced by using the single isotope 7 Li and by the very similar radii of Er 3+ and the Y 3+ ions for which it substitutes. To show the practicability of cryogen-free cooling, this laser stability was obtained with the reference crystal at 5 K; moreover, this performance did not require vibrational isolation of either the laser or crystal frequency reference. Stabilization is feasible up to T=25 K where the Er 3+ absorption thermally broadens to ∼500 MHz. This stabilized laser system provides a tool for interferometry, high-resolution spectroscopy, real-time optical signal processing based on spatial spectral holography and accumulated photon echoes, secondary frequency standards, and other applications such as quantum information science requiring narrow-band light sources or coherent detection

Dependence of the up-conversion emission of Li+ co-doped Y2O3:Er3+ films with dopant concentration

International Nuclear Information System (INIS)

Meza-Rocha, A.N.; Huerta, E.F.; Caldiño, U.; Carmona-Téllez, S.; Bettinelli, M.; Speghini, A.; Pelli, S.; Righini, G.C.

2015-01-01

The effect of dopant concentration on the up-conversion emission, and in particular on the Er 3+ related green and red emissions of spray pyrolysis deposited films of Y 2 O 3 :Er 3+ co-doped with Li + , is reported. Er 3+ concentrations in the films in the range of 1.1–5.6 at% (1.5–14 at% Er 3+ in the spraying solution) were studied, as well as the effect of co-doping them with Li + . Large concentrations of Er 3+ favor the red emission, especially for contents higher than 10 at% in the spraying solution. Li + co-doping improves the green and red emissions up to 365 and 171 times, respectively, depending on the Er 3+ and Li + concentrations. - Highlights: Up-converting Y 2 O 3 :Er 3+ and Y 2 O 3 :Er 3+ , Li + films were deposited by spray pyrolysis. The effect of Li + co-doping on the green and red UC Er 3+ emission is reported. Li + co-doping improves the green and red emission up to 365 and 171 times

Crystalline phase, profile characteristics and spectroscopic properties of Er3+/Tm3+-diffusion-codoped LiNbO3 crystal

International Nuclear Information System (INIS)

Sun, Wen-Bao; Zhang, Zi-Bo; Sun, Hong-Xue; Wong, Wing-Han; Yu, Dao-Yin; Pun, Edwin Yue-Bun

2017-01-01

Er 3+ /Tm 3+ -codoped LiNbO 3 crystal was prepared by co-diffusion of stacked Er and Tm metal films coated onto surface of off-congruent, Li-deficient LiNbO 3 substrate produced by Li-poor vapor transport equilibration technique. The crystalline phase on the diffused surface was analyzed by X-ray single-crystal diffraction. The Er 3+ and Tm 3+ profile characteristics were studied by secondary ion mass spectrometry. The emission spectra were measured under the 980 or 795 nm wavelength excitation, and the emission and absorption cross section spectra were calculated based upon McCumber theory. The lifetimes of some emissions were measured. The results show that the Er 3+ and Tm 3+ ions presence is in the form of LiNbO 3 phase. Both ions obey to Gaussian profile with a diffusion depth 21.5 μm. In the codoping case, both ions keep their respective spectroscopic features of only doping case and do not affect each other. The codoping enables to combine the wavelength emissions of both ions and the resultant emission band in the telecommunication window around 1.5 μm is as wide as 150 nm, providing the possibility of S+C+L broadband amplification by employing commercial 980 and 795 nm laser diodes as the pump sources. The Er 3+ /Tm 3+ -codoped LN is a promising host material for integrated optics. - Graphical abstract: Er 3+ /Tm 3+ -codoped LiNbO 3 crystal was prepared by co-diffusion of stacked Er and Tm metal films. The crystalline phase, diffusion profile and cross section spectra of Er 3+ and Tm 3+ ions in the diffusion layer have been investigated. The results show that the presence of Er 3+ and Tm 3+ ions is in the LiNbO 3 phase. Both ions follow Gaussian profile with a diffusion depth 21.5 μm. Both ions keep their respective spectroscopic features of only doping case. Excited state absorption is the dominant process for 795-nm-upconvered fluorescence of Tm 3+ . The codoping enables to combine the wavelength emissions of both ions and provide the possibility of S

Investigation of thermal stability and spectroscopic properties in Er3+ doped bismuth-boron-germanium glasses

International Nuclear Information System (INIS)

Nie Qiuhua; Lu Longjun; Dai Shixun; Xu Tiefeng; Shen Xiang; Zhang Xudong; Liang Xiaowei; Zhang Xianghua

2007-01-01

A series of Er 3+ -doped 50Bi 2 O 3 -(50-x)B 2 O 3 -xGeO 2 +0.5 wt% Er 2 O 3 (x=0, 5, 10, 15, 20 mol%) glasses were prepared. The thermal stability, absorption spectra, emission spectra and lifetime of the 4 I 13 / 2 level of Er 3+ ions were measured and studied. It is found that the absorption cross-section of Er 3+ , emission intensity and lifetime of the 4 I 13 / 2 level of Er 3+ increase with increasing GeO 2 content in the glass composition, while the fluorescence full-width at half-maximum (FWHM) at 1.5 μm of Er 3+ is about 79 nm in x=20 mol% glass sample under 970 nm pump. The obtained data suggest that this system glass can be used as a candidate host material for potential broadband optical amplifiers

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.

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

Effects of material growth technique and Mg doping on Er3+ photoluminescence in Er-implanted GaN

International Nuclear Information System (INIS)

Kim, S.; Henry, R. L.; Wickenden, A. E.; Koleske, D. D.; Rhee, S. J.; White, J. O.; Myoung, J. M.; Kim, K.; Li, X.; Coleman, J. J.

2001-01-01

Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies have been carried out at 6 K on the ∼1540 nm 4 I 13/2 - 4 I 15/2 emissions of Er 3+ in Er-implanted and annealed GaN. These studies revealed the existence of multiple Er 3+ centers and associated PL spectra in Er-implanted GaN films grown by metalorganic chemical vapor deposition, hydride vapor phase epitaxy, and molecular beam epitaxy. The results demonstrate that the multiple Er 3+ PL centers and below-gap defect-related absorption bands by which they are selectively excited are universal features of Er-implanted GaN grown by different techniques. It is suggested that implantation-induced defects common to all the GaN samples are responsible for the Er site distortions that give rise to the distinctive, selectively excited Er 3+ PL spectra. The investigations of selectively excited Er 3+ PL and PLE spectra have also been extended to Er-implanted samples of Mg-doped GaN grown by various techniques. In each of these samples, the so-called violet-pumped Er 3+ PL band and its associated broad violet PLE band are significantly enhanced relative to the PL and PLE of the other selectively excited Er 3+ PL centers. More importantly, the violet-pumped Er 3+ PL spectrum dominates the above-gap excited Er 3+ PL spectrum of Er-implanted Mg-doped GaN, whereas it was unobservable under above-gap excitation in Er-implanted undoped GaN. These results confirm the hypothesis that appropriate codopants can increase the efficiency of trap-mediated above-gap excitation of Er 3+ emission in Er-implanted GaN. [copyright] 2001 American Institute of Physics

Synthesis and cathodoluminescence characterization of ZrO2:Er3+ films

International Nuclear Information System (INIS)

Martínez-Hernández, A.; Guzmán-Mendoza, J.; Rivera-Montalvo, T.; Sánchez-Guzmán, D.; Guzmán-Olguín, J.C.; García-Hipólito, M.; Falcony, C.

2014-01-01

Trivalent erbium doped zirconium oxide films were deposited by the ultrasonic spray pyrolysis technique. Films were deposited using zirconium tetrachloride octahydrate (ZrCl 4 O·8H 2 O) and erbium nitrate hexahydrate ((NO 3 ) 3 Er·6H 2 O) as precursors and deionized water as solvent. The dopant concentrations in the spray solution were 1, 3, 5, 10 and 15 at% in ratio to zirconium content. The films were deposited on corning glass substrates at different temperatures from 400 up to 550 °C. Films deposited at temperatures lower than 400 °C were amorphous, however, as substrate temperatures are increased, the ZrO 2 films presented a better crystallinity and showed a tetragonal phase. Cathodoluminescence (CL) emission spectra showed bands centred at 524, 544 and 655 nm associated with the electronic transition of Er 3+ . - Highlights: • The films of ZrO 2 :Er 3+ were obtained by spray pyrolysis. • Emission spectra of ZrO 2 :Er 3+ films were reported. • Cathodoluminescence of ZrO 2 :Er 3+ films was analyzed. • Cathodoluminescence of ZrO 2 :Er 3+ films showed strong dependence on substrate temperature and electron voltage

Investigation on Er{sup 3+}/Ho{sup 3+} co-doped silicate glass for ~2 µm fiber lasers

Energy Technology Data Exchange (ETDEWEB)

Liu, Xueqiang; Huang, Feifei; Cheng, Jimeng; Fan, Xiaokang; Gao, Song [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of Chinese Academy of Science, Beijing 100039 (China); Zhang, Junjie [College of Materials Science and Technology, China Jiliang University, Hangzhou 310018 (China); Hu, Lili [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Chen, Danping, E-mail: dpchen2008@aliyun.com [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

2015-06-15

A stable Er{sup 3+}/Ho{sup 3+} co-doped lead silicate glass is developed. Luminescent properties are recorded under pumping with 808 and 1550 nm lasers. Energy-transfer mechanism and efficiency are analyzed. Energy-transfer efficiency from Er{sup 3+}:{sup 4}I{sub 13/2} to Ho{sup 3+}:{sup 5}I{sub 7} reaches 93.8% at 3 mol% Ho{sub 2}O{sub 3} doping concentration. Strong luminescence is detected when pumped at 1550 nm because of efficient energy transfer from Er{sup 3+}:{sup 4}I{sub 13/2} to Ho{sup 3+}:{sup 5}I{sub 7}. Peak gain coefficient at 2056 nm is detected as 1.62 cm{sup −1}. The excellent luminescent property and high stability indicate that Er{sup 3+}/Ho{sup 3+} co-doped lead silicate glass can be applied in 2 µm fiber lasers. - Highlights: • Er{sup 3+}/Ho{sup 3+} co-doped silicate glasses with high stability are prepared. • Strong luminescence is detected under pump of 1550 nm lasers owing to efficient energy transfer from Er{sup 3+} to Ho{sup 3+}. • Transfer efficiency is calculated to be 93.8% when Ho{sub 2}O{sub 3} doping concentration is up to 3 mol%. • Gain coefficient peaks at 2056 nm to be 1.62 cm{sup −1}.

Structural and optical studies of Er3+-doped alkali/alkaline oxide containing zinc boro-aluminosilicate glasses for 1.5 μm optical amplifier applications

Science.gov (United States)

Kaky, Kawa M.; Lakshminarayana, G.; Baki, S. O.; Lira, A.; Caldiño, U.; Meza-Rocha, A. N.; Falcony, C.; Kityk, I. V.; Taufiq-Yap, Y. H.; Halimah, M. K.; Mahdi, M. A.

2017-07-01

In the present work, we report on the optical spectral properties of Er3+-doped zinc boro-aluminosilicate glasses with an addition of 10 mol % alkali/alkaline modifier regarding the fabrication of new optical materials for optical amplifiers. A total of 10 glasses were prepared using melt-quenching technique with the compositions (40-x)B2O3 - 10SiO2 - 10Al2O3 - 30ZnO - 10Li2O - xEr2O3 and (40-x)B2O3 - 10SiO2 - 10Al2O3 - 30ZnO - 10MgO - xEr2O3 (x = 0.1, 0.25, 0.5, 1.0, and 2.0 mol %). We confirm the amorphous-like structure for all the prepared glasses using X-ray diffraction (XRD). To study the functional groups of the glass composition after the melt-quenching process, Raman spectroscopy was used, and various structural units such as triangular and tetrahedral-borates (BO3 and BO4) have been identified. All the samples were characterized using optical absorption for UV, visible and NIR regions. Judd-Ofelt (JO) intensity parameters (Ωλ, λ = 2, 4 and 6) were calculated from the optical absorption spectra of two glasses LiEr 2.0 and MgEr 2.0 (doped with 2 mol % of Er3+). JO parameters for LiEr 2.0 and MgEr 2.0 glasses follow the trend as Ω6>Ω2>Ω4. Using Judd-Ofelt intensity parameters, we obtained radiative probability A (S-1), branching ratios (β), radiative decay lifetimes τrad (μs) of emissions from excited Er+3 ions in LiEr 2.0 and MgEr 2.0 to all lower levels. Quantum efficiency (η) of 4I13/2 and 4S3/2 levels for LiEr 2.0 and MgEr 2.0 with and without 4D7/2 level was calculated using the radiative decay lifetimes τrad. (μs) and measured lifetimes τexp. (μs). We measured the visible photoluminescence under 377 nm excitation for both LiEr and MgEr glass series within the region 390-580 nm. Three bands were observed in the visible region at 407 nm, 530 nm, and 554 nm, as a result of 2H9/2 → 4I15/2, 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions, respectively. Decay lifetimes for emissions at 407 nm, 530 nm, and 554 nm were measured and they show

Er3+-Al2O3 nanoparticles doping of borosilicate glass

International Nuclear Information System (INIS)

Massera, Jonathan; Petit, Laeticia; Hupa, Leena; Hupa, Mikko; Koponen, Joona; Glorieux, Benoit

2015-01-01

Novel borosilicate glasses were developed by adding in the glass batch Er 3+ -Al 2 O 3 nanoparticles synthetized by using a soft chemical method. A similar nanoparticle doping with modified chemical vapour deposition (MCVD) process was developed to increase the efficiency of the amplifying silica fibre in comparison to using MCVD and solution doping. It was shown that with the melt quench technique, a Er 3+ -Al 2 O 3 nanoparticle doping neither leads to an increase in the Er 3+ luminescence properties nor allows one to control the rare-earth chemical environment in a borosilicate glass. The site of Er 3+ in the Er 3+ -Al 2 O 3 nanoparticle containing glass seems to be similar as in glasses with the same composition prepared using standard raw materials. We suspect the Er 3+ ions to diffuse from the nanoparticles into the glass matrix. There was no clear evidence of the presence of Al 2 O 3 nanoparticles in the glasses after melting. (author)

Ellipsometric studies of ErMnO₃ single crystals

DEFF Research Database (Denmark)

Babonas, G.-J.; Grivel, Jean-Claude; Reza, A.

2007-01-01

Ellipsometric studies of ErMnO3 single crystals have been carried out in the spectral range of 1-5 eV by means of photometric ellipsometers. Experimental ellipsometric data were analysed in the uniaxial crystal model. For the first time, the components of dielectric function of ErMnO3 were...

Enhanced ~2.7 µm emission investigation of Er{sup 3+}:{sup 4}I{sub 11/2}→{sup 4}I{sub 13/2} transition in Yb,Er,Pr:SrLaGa{sub 3}O{sub 7} crystal

Energy Technology Data Exchange (ETDEWEB)

Wang, Yan [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Zhang, Baotong [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); College of Materials Science and Engineering, Fujian Normal University, Fuzhou, Fujian 350007 (China); Li, Jianfu; Zhu, Zhaojie; You, Zhenyu [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Tu, Chaoyang, E-mail: tcy@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2017-03-15

The bulk crystal of 5at% Yb{sup 3+}, 20 at% Er{sup 3+} and 0.2 at% Pr{sup 3+} triply doped SrLaGa{sub 3}O{sub 7} (abbr. as Yb,Er,Pr:SLGO) was grown by the Czochralski method. The effects of co-dopant Yb{sup 3+} and Pr{sup 3+} on the spectroscopic properties and the mutual energy transfer mechanism were investigated, via the measurements of its absorption, near-infrared and mid-infrared fluorescence spectra, as well as the fluorescence decay curves of Er{sup 3+}:{sup 4}I{sub 13/2} and {sup 4}I{sub 11/2} levels at room temperature. As compared with 20at% Er{sup 3+} singly doped SrLaGa{sub 3}O{sub 7} crystal, ~2.7 µm emission intensity corresponding to Er{sup 3+}:{sup 4}I{sub 11/2}→{sup 4}I{sub 13/2} transition is enhanced greatly in the Yb,Er,Pr:SLGO crystal. Spectral analyses indicate that the sensitization of Yb{sup 3+} to Er{sup 3+} improves the ~2.7 µm emission in Yb,Er,Pr:SLGO crystal, meanwhile, the depopulation of Pr{sup 3+} from Er{sup 3+} decreases the ~1.5 µm emission and inhibits the self-termination effect. The energy transfer efficiencies of Yb{sup 3+}→Er{sup 3+} (ET1), Er{sup 3+}→Pr{sup 3+} (ET2) and Er{sup 3+}→Pr{sup 3+} (ET3) were estimated and discussed. The above results conclude that Yb,Er,Pr:SLGO crystal is a good candidate for LD pumped mid-infrared laser. - Graphical abstract: As compared with Er: SrLaGa{sub 3}O{sub 7} crystal, ~2.7 µm MIR emissions corresponding to Er{sup 3+}:{sup 4}I{sub 11/2}→{sup 4}I{sub 13/2} transition were enhanced in Yb{sup 3+}, Er{sup 3+} and Pr{sup 3+} triply doped SrLaGa{sub 3}O{sub 7} crystal owing to the sensitization of co-dopant Yb{sup 3+} via ET1, at the same time, ~1.5 µm NIR emissions were weakened owing to the depopulation of co-dopant Pr{sup 3+} via ET3.

Lysosomes shape Ins(1,4,5)P3-evoked Ca2+ signals by selectively sequestering Ca2+ released from the endoplasmic reticulum

Science.gov (United States)

López-Sanjurjo, Cristina I.; Tovey, Stephen C.; Prole, David L.; Taylor, Colin W.

2013-01-01

Summary Most intracellular Ca2+ signals result from opening of Ca2+ channels in the plasma membrane or endoplasmic reticulum (ER), and they are reversed by active transport across these membranes or by shuttling Ca2+ into mitochondria. Ca2+ channels in lysosomes contribute to endo-lysosomal trafficking and Ca2+ signalling, but the role of lysosomal Ca2+ uptake in Ca2+ signalling is unexplored. Inhibition of lysosomal Ca2+ uptake by dissipating the H+ gradient (using bafilomycin A1), perforating lysosomal membranes (using glycyl-L-phenylalanine 2-naphthylamide) or lysosome fusion (using vacuolin) increased the Ca2+ signals evoked by receptors that stimulate inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] formation. Bafilomycin A1 amplified the Ca2+ signals evoked by photolysis of caged Ins(1,4,5)P3 or by inhibition of ER Ca2+ pumps, and it slowed recovery from them. Ca2+ signals evoked by store-operated Ca2+ entry were unaffected by bafilomycin A1. Video-imaging with total internal reflection fluorescence microscopy revealed that lysosomes were motile and remained intimately associated with the ER. Close association of lysosomes with the ER allows them selectively to accumulate Ca2+ released by Ins(1,4,5)P3 receptors. PMID:23097044

Chaperone-Mediated Sec61 Channel Gating during ER Import of Small Precursor Proteins Overcomes Sec61 Inhibitor-Reinforced Energy Barrier

Directory of Open Access Journals (Sweden)

Sarah Haßdenteufel

2018-05-01

Full Text Available Summary: Protein transport into the mammalian endoplasmic reticulum (ER is mediated by the heterotrimeric Sec61 channel. The signal recognition particle (SRP and TRC systems and Sec62 have all been characterized as membrane-targeting components for small presecretory proteins, whereas Sec63 and the lumenal chaperone BiP act as auxiliary translocation components. Here, we report the transport requirements of two natural, small presecretory proteins and engineered variants using semipermeabilized human cells after the depletion of specific ER components. Our results suggest that hSnd2, Sec62, and SRP and TRC receptor each provide alternative targeting pathways for short secretory proteins and define rules of engagement for the actions of Sec63 and BiP during their membrane translocation. We find that the Sec62/Sec63 complex plus BiP can facilitate Sec61 channel opening, thereby allowing precursors that have weak signal peptides or other inhibitory features to translocate. A Sec61 inhibitor can mimic the effect of BiP depletion on Sec61 gating, suggesting that they both act at the same essential membrane translocation step. : Protein transport into the human endoplasmic reticulum (ER is mediated by the heterotrimeric Sec61 channel. Haßdenteufel et al. map the determinants for requirement of different targeting pathways and different auxiliary components of the Sec61 channel in ER import of short presecretory proteins. Different characteristics of precursor polypeptides dictate the engagement of each component. Keywords: endoplasmic reticulum, protein targeting and translocation, Sec61 channel gating, Sec62, Sec63, BiP, CAM741, signal peptide, mature region, cluster of positive charges

Er3+ infrared fluorescence affected by spatial distribution synchronicity of Ba2+ and Er3+ in Er3+-doped BaO–SiO2 glasses

Directory of Open Access Journals (Sweden)

Atsunobu Masuno

2016-02-01

Full Text Available Glasses with the composition xBaO–(99.9 − xSiO2–0.1ErO3/2 (0 ≤x ≤ 34.9 were fabricated by a levitation technique. The glasses in the immiscibility region were opaque due to chemical inhomogeneity, while the other glasses were colorless and transparent. The scanning electron microscope observations and electron probe microanalysis scan profiles revealed that more Er3+ ions were preferentially distributed in the regions where more Ba2+ ions existed in the chemically inhomogeneous glasses. The synchronicity of the spatial distributions of the two ions initially increased with increasing x and then decreased when the Ba2+ concentration exceeded a certain value. The peak shape and lifetime of the fluorescence at 1.55 μm depended on x as well as the spatial distribution of both ions. These results indicate that although ErOn polyhedra are preferentially coordinated with Ba2+ ions and their local structure is affected by the coordination of Ba2+, there is a maximum in the amount of Ba2+ ions that can coordinate ErOn polyhedra since the available space for Ba2+ ions is limited. These findings provide us with efficient ways to design the chemical composition of glasses with superior Er3+ fluorescence properties for optical communication network systems.

Optical transitions of Er3+/Yb3+ codoped TeO2-WO3-Bi2O3 glass.

Science.gov (United States)

Shen, Xiang; Nie, Qiuhua; Xu, Tiefeng; Gao, Yuan

2005-10-01

Optical absorption and emission properties of the Er3+/Yb3+ codoped TeO2-WO3-Bi2O3 (TWB) glass has been investigated. The transition probabilities, excited state lifetimes, and the branching ratios have been predicted for Er3+ based on the Judd-Ofelt theory. The broad 1.5 microm fluorescence was observed under 970 nm excitation, and its full width at half maximum (FWHM) is 77 nm. The emission cross-section is calculated using the McCumber theory, and the peak emission cross-section is 1.03 x 10(-21) cm2 at 1.531 microm. This value is much larger than those of the silicate and phosphate glasses. Efficient green and weak red upconversion luminescence from Er3+ centers in the glass sample was observed at room temperature, and the upconversion excitation processes have been analyzed.

Apical microinfiltration evaluation of radicular channels irradiated with Er:YAG laser in vitro

International Nuclear Information System (INIS)

Sebrao, Catia Cilene Nass

2003-01-01

It was evaluated, in vitro, the adaptation of the filling material (Sealer 2S R ) to the root channels dentine walls treated using the endodontic technique and prepared with the Er:YAG laser, by the technique of infiltration of methylene blue dye. Using scanning electronic microscopy, the morphologic alteration of the root channel dentine was observed for one sample per studied group. Also, an evaluation of the temperature increase in the external surface of the root during the irradiations was performed for two samples per group. For each group of samples, with eleven roots each, two sub-groups had been considered: the dry, irradiated after completely dry with absorbent cones of paper, and the humid, where a cone of absorbent paper was applied for two seconds in the root canal, leaving them lightly humidified. Considering the used energies for the irradiations, the groups are: G1, control (without irradiation), G2-dry (100 mJ-10 Hz), G2-humid (100 mJ-10 Hz), G3-dry (140 mJ-6 Hz), G3-humid (140 mJ-6 Hz), G4-dry (180 mJ-6 Hz), and G4-humid (180 mJ-6 Hz). The results had shown that apical microinfiltration did not exhibit significant difference among groups. The highest increase in temperature was observed for the dry groups, with the maximum variation of temperature of 6.5 deg C. Under the scanning electronic microscopy analysis, the humid groups had presented cleaner surfaces than the dry groups. The G4-humid group presented extensive regions of fusion and resolidification of the dentine. (author)

Crystalline phase, profile characteristics and spectroscopic properties of Er{sup 3+}/Tm{sup 3+}-diffusion-codoped LiNbO{sub 3} crystal

Energy Technology Data Exchange (ETDEWEB)

Sun, Wen-Bao [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Zhang, Zi-Bo [Department of Engineering, Pierre and Marie Curie University (University of Paris VI), 4 place Jussieu, 75005 Paris (France); Sun, Hong-Xue [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Wong, Wing-Han, E-mail: eewhwong@cityu.edu.hk [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Yu, Dao-Yin [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Pun, Edwin Yue-Bun [Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); and others

2017-04-15

Er{sup 3+}/Tm{sup 3+}-codoped LiNbO{sub 3} crystal was prepared by co-diffusion of stacked Er and Tm metal films coated onto surface of off-congruent, Li-deficient LiNbO{sub 3} substrate produced by Li-poor vapor transport equilibration technique. The crystalline phase on the diffused surface was analyzed by X-ray single-crystal diffraction. The Er{sup 3+} and Tm{sup 3+} profile characteristics were studied by secondary ion mass spectrometry. The emission spectra were measured under the 980 or 795 nm wavelength excitation, and the emission and absorption cross section spectra were calculated based upon McCumber theory. The lifetimes of some emissions were measured. The results show that the Er{sup 3+} and Tm{sup 3+} ions presence is in the form of LiNbO{sub 3} phase. Both ions obey to Gaussian profile with a diffusion depth 21.5 μm. In the codoping case, both ions keep their respective spectroscopic features of only doping case and do not affect each other. The codoping enables to combine the wavelength emissions of both ions and the resultant emission band in the telecommunication window around 1.5 μm is as wide as 150 nm, providing the possibility of S+C+L broadband amplification by employing commercial 980 and 795 nm laser diodes as the pump sources. The Er{sup 3+}/Tm{sup 3+}-codoped LN is a promising host material for integrated optics. - Graphical abstract: Er{sup 3+}/Tm{sup 3+}-codoped LiNbO{sub 3} crystal was prepared by co-diffusion of stacked Er and Tm metal films. The crystalline phase, diffusion profile and cross section spectra of Er{sup 3+} and Tm{sup 3+} ions in the diffusion layer have been investigated. The results show that the presence of Er{sup 3+} and Tm{sup 3+} ions is in the LiNbO{sub 3} phase. Both ions follow Gaussian profile with a diffusion depth 21.5 μm. Both ions keep their respective spectroscopic features of only doping case. Excited state absorption is the dominant process for 795-nm-upconvered fluorescence of Tm{sup 3+}. The

On the enhancement of Er{sup 3+} diffusion in LiNbO{sub 3} crystals by Er{sup 3+}/Ti{sup 4+} co-diffusion

Energy Technology Data Exchange (ETDEWEB)

Almeida, José Manuel Marques Martins de, E-mail: jmmma@utad.pt [INESC-TEC, Rua do Campo Alegre, 687, Porto 4169-007 (Portugal); Department of Physics, School of Science and Technology, University of Trás-os-Montes e Alto Douro, PO. Box 1013, 5001-801 Vila Real (Portugal); Sada, Cinzia [Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Via Marzolo 8, 35131 Padova (Italy)

2016-02-15

Highlights: • Enhancement of the diffusion of erbium ions (Er{sup 3+}) in lithium niobate crystals. • Incoherence on published results lead to need for systematic revision of literature. • Further insight into the topic of co-diffusion of Er{sup 3+}/Ti{sup 4+} ions into LiNbO{sub 3}. - Abstract: After carrying out a revision of the literature on the enhancement of Er{sup 3+} diffusion in LiNbO{sub 3} crystals by Er{sup 3+}/Ti{sup 4+} co-diffusion and analyzing our own experimental results, we conclude that no reproducible results were reported, meaning that further research on this subject is necessary.

FANS-3D Users Guide (ESTEP Project ER 201031)

Science.gov (United States)

2016-08-01

TECHNICAL DOCUMENT 3293 August 2016 FANS -3D User’s Guide (ESTEP Project ER-201031) Pei-Fang Wang SSC Pacific Hamn-Ching...1.1 THEORY AND NUMERICAL ALGORITHM OF FANS CODE ............................................. 1 2. FANS -3D SOFTWARE DOCUMENTATION AND EXECUTION...5 3. FANS -3D CODE PARALLELIZATION

Large rotating magnetocaloric effect in ErAlO3 single crystal

Directory of Open Access Journals (Sweden)

X. Q. Zhang

2017-05-01

Full Text Available Magnetic and magnetocaloric properties of ErAlO3 single crystal were investigated. Magnetization of ErAlO3 shows obvious anisotropy when magnetic field is applied along the a, b and c axes, which leads to large anisotropic magnetic entropy change. In particular, large rotating field entropy change from the b to c axis within the bc plane is obtained and reaches 9.7 J/kg K at 14 K in a field of 5 T. This suggests the possibility of using ErAlO3 single crystal for magnetic refrigerators by rotating its magnetization vector rather than moving it in and out of the magnet.

Optical and dielectric properties of isothermally crystallized nano-KNbO3 in Er3+-doped K2O-Nb2O5-SiO2 glasses.

Science.gov (United States)

Chaliha, Reenamoni Saikia; Annapurna, K; Tarafder, Anal; Tiwari, V S; Gupta, P K; Karmakar, Basudeb

2010-01-01

Precursor glass of composition 25K(2)O-25Nb(2)O(5)-50SiO(2) (mol%) doped with Er(2)O(3) (0.5 wt% in excess) was isothermally crystallized at 800 degrees C for 0-100 h to obtain transparent KNbO(3) nanostructured glass-ceramics. XRD, FESEM, TEM, FTIRRS, dielectric constant, refractive index, absorption and fluorescence measurements were carried out to analyze the morphology, dielectric, structure and optical properties of the glass-ceramics. The crystallite size of KNbO(3) estimated from XRD and TEM is found to vary in the range 7-23 nm. A steep rise in the dielectric constant of glass-ceramics with heat-treatment time reveals the formation of ferroelectric nanocrystalline KNbO(3) phase. The measured visible photoluminescence spectra have exhibited green emission transitions of (2)H(11/2), (4)S(3/2)-->(4)I(15/2) upon excitation at 377 nm ((4)I(15/2)-->(4)G(11/2)) absorption band of Er(3+) ions. The near infrared (NIR) emission transition (4)I(13/2)-->(4)I(15/2) is detected around 1550 nm on excitation at 980 nm ((4)I(15/2)-->(4)I(11/2)) of absorption bands of Er(3+) ions. It is observed that photoluminescent intensity at 526 nm ((2)H(11/2)-->(4)I(15/2)), 550 nm ((4)S(3/2)-->(4)I(15/2)) and 1550 nm ((4)I(13/2)-->(4)I(15/2)) initially decrease and then gradually increase with increase in heat-treatment time. The measured lifetime (tau(f)) of the (4)I(13/2)-->(4)I(15/2) transition also possesses a similar trend. The measured absorption and fluorescence spectra reveal that the Er(3+) ions gradually enter into the KNbO(3) nanocrystals. Copyright 2009 Elsevier B.V. All rights reserved.

White phosphor using Yb3+-sensitized Er3+-and Tm3+-doped sol-gel derived lead-fluorosilicate transparent glass ceramic excited at 980 nm

Science.gov (United States)

Tavares, M. C. P.; da Costa, E. B.; Bueno, L. A.; Gouveia-Neto, A. S.

2018-01-01

Generation of primary colors and white light through frequency upconversion using sol-gel derived 80SiO2:20PbF2 vitroceramic phosphors doped with Er3+, Er3+/Yb3+, Tm3+/Yb3+, and Er3+/Tm3+/Yb3+ excited at 980 nm is demonstrated. For Er3+ and Er3+/Yb3+ doped samples emissions were obtained in the blue (410 nm), green (530, and 550 nm) and red (670 nm) regions, corresponding to the 2H9/2 → 4I15/2,2H11/2 → 4I15/2, 4S3/2 → 4I152 and 4F9/2 → 4I15/2 transitions of Er3+, respectively. The codoping with Yb3+ ions altered the spectral profile of most of the emissions compared to the single doped samples, resulting in changes in the emitted color, in addition to a significant increase in the emission intensity. In Tm3+/Yb3+ co-doped samples visible emissions in the blue (480 nm), and red (650 nm), corresponding to transitions 1G4 → 3H6 and 1G4 → 3F4 of Tm3+, respectively, were obtained. The emission intensity around 480 nm overcome the red emission, and luminescence showed a predominantly blue tone. White light with CIE-1931 coordinates (0.36; 0.34) was produced by homogeneously mixing up powders of heat treated at 400 °C co-doped samples 5.0Er3+/5.0Yb3+ and 0.5Tm3+/2.5Yb3+ in the mass ratio of 13%, and 87%, respectively. The measured emission spectrum for a sample resulting from the mixture showed a profile with very good agreement with the spectrum found from the superimposition of the spectra of the co-doped samples.

Silver nanoparticles enhanced 1.53 µm band fluorescence of Er{sup 3+}/Yb{sup 3+} codoped tellurite glasses

Energy Technology Data Exchange (ETDEWEB)

Qi, Yawei; Zhou, Yaxun, E-mail: zhouyaxun@nbu.edu.cn; Wu, Libo; Yang, Fengjing; Peng, Shengxi; Zheng, Shichao; Yin, Dandan

2014-09-15

The silver nanoparticles (NPs) was introduced into the Er{sup 3+}/Yb{sup 3+} codoped tellurite glasses with composition of TeO{sub 2}–ZnO to improve the 1.53 µm band fluorescence of Er{sup 3+} and the thermal stability of glass host. The UV–Vis–NIR absorption spectra, 1.53 µm band fluorescence spectra and fluorescence decaying curves, the differential scanning calorimeter (DSC) curves, X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images of glass samples were characterized to investigate the effect of silver NPs on the fluorescence properties of Er{sup 3+}, thermal stability and structure behavior of glass host. It is shown that the Er{sup 3+}/Yb{sup 3+} codoped tellurite glass emits intense 1.53 µm band fluorescence with peak wavelength located at about 1532 nm under the 980 nm excitation. The introduction of silver NPs further improves the fluorescence intensity of Er{sup 3+} which is attributed to the enhanced local electric field effect induced by localized surface Plasmon resonance (LSPR) of silver NPs and the possible energy transfer from silver NPs to Er{sup 3+}. An improvement by about 62% of 1.5{sup 3} µm band fluorescence intensity was found in the studied Er{sup 3+}/Yb{sup 3+} codoped tellurite glass containing 0.5 mol% amount of AgNO{sub 3}. In addition, the thermal stability of glass host increases with the introduction of silver NPs while the glass structure maintains the amorphous nature. The present results indicate that the prepared Er{sup 3+}/Yb{sup 3+} codoped tellurite glass with an appropriate amount of silver NPs has good prospect as a gain medium applied for 1.53 µm band broad and high-gain erbium-doped fiber amplifiers (EDFAs). - Highlights: • Tellurite glass with Er{sup 3+}/Yb{sup 3+} and silver NPs was prepared by melt-quenching method. • Silver NPs with average size of 12 nm and Plasmon band at 560 nm was observed. • Addition of silver NPs increased the thermal stability of tellurite glass. �

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.)

Luminescence of Er3+ doped double lead halide crystals under X-ray, UV, VIS and IR excitation

Science.gov (United States)

Serazetdinov, A. R.; Smirnov, A. A.; Pustovarov, V. A.; Isaenko, L. I.

2017-09-01

Er3+ doped double lead halide crystals incorporate a number of properties making them interesting for practical use in light conducting materials. X-ray excited luminescence (XRL) spectra, photoluminescence (PL) spectra in region of 1.5-3.5 eV, photoluminescence excitation (PLE) spectra (2.75-5 eV) and anti-stokes luminescence (ASL) spectra were measured at room temperature in KPb2Cl5 (KPC) and RbPb2Br5 (RPB) matrices doped with Er3+ (1%) ions and in KPC doped with Er3++ Yb3+ ions(1:3 ratio concentration). Intraconfigurational f→f transitions are observed in Er3+ ions in most of the cases. The concrete spectrum form is strongly dependent on the excitation energy. Under 980 nm excitation upper Er3+ levels are excited, showing upconversional processes. In case of 313 nm (UV) and 365 nm (VIS) excitation self trapped exciton luminescence was detected in RPB crystal. Additional Yb3+ doping ions strongly increase quantum yield under 980 nm excitation and this doping cause insignificant influence on quantum yield under VIS or UV excitation.

Order of magnetic transition and large magnetocaloric effect in Er3Co

International Nuclear Information System (INIS)

Jun, Shen; Jian-Feng, Wu; Jin-Liang, Zhao; Feng-Xia, Hu; Ji-Rong, Sun; Bao-Gen, Shen

2010-01-01

We have studied the magnetic and magnetocaloric properties of the Er 3 Co compound, which undergoes ferromagnetic ordering below the Curie temperature T C = 13 K. It is found by fitting the isothermal magnetization curves that the Landau model is appropriate to describe the Er 3 Co compound. The giant magnetocaloric effect (MCE) without hysteresis loss around T C is found to result from the second-order ferromagnetic-to-paramagnetic transition. The maximal value of magnetic entropy change is 24.5 J/kg·K with a refrigerant capacity (RC) value of 476 J/kg for a field change of 0–5 T. Large reversible MEC and RC indicate the potentiality of Er 3 Co as a candidate magnetic refrigerant at low temperatures. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

ACBD5 and VAPB mediate membrane associations between peroxisomes and the ER.

Science.gov (United States)

Costello, Joseph L; Castro, Inês G; Hacker, Christian; Schrader, Tina A; Metz, Jeremy; Zeuschner, Dagmar; Azadi, Afsoon S; Godinho, Luis F; Costina, Victor; Findeisen, Peter; Manner, Andreas; Islinger, Markus; Schrader, Michael

2017-02-01

Peroxisomes (POs) and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism and form tight structural associations, which were first observed in ultrastructural studies decades ago. PO-ER associations have been suggested to impact on a diverse number of physiological processes, including lipid metabolism, phospholipid exchange, metabolite transport, signaling, and PO biogenesis. Despite their fundamental importance to cell metabolism, the mechanisms by which regions of the ER become tethered to POs are unknown, in particular in mammalian cells. Here, we identify the PO membrane protein acyl-coenzyme A-binding domain protein 5 (ACBD5) as a binding partner for the resident ER protein vesicle-associated membrane protein-associated protein B (VAPB). We show that ACBD5-VAPB interaction regulates PO-ER associations. Moreover, we demonstrate that loss of PO-ER association perturbs PO membrane expansion and increases PO movement. Our findings reveal the first molecular mechanism for establishing PO-ER associations in mammalian cells and report a new function for ACBD5 in PO-ER tethering. © 2017 Costello et al.

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.

Magnetic phase transitions in Er7Rh3 studied on single crystals

International Nuclear Information System (INIS)

Tsutaoka, Takanori; Obata, Keisuke; Cheyvuth, Seng; Koyama, Keiichi

2014-01-01

Highlights: • Magnetic and electrical properties of Er 7 Rh 3 were studied on single crystals. • The magnetic phase diagram along the c-axis was constructed. • The field-induced magnetic transitions in Er 7 Rh 3 can be explained by the magnetic structure with two magnetic propagation vectors. • The anomalies of electrical resistivity can also be described by the magnetic structure in Er 7 Rh 3 . - Abstract: Magnetic phase transitions in Er 7 Rh 3 with the Th 7 Fe 3 type hexagonal structure have been studied on single crystals by measuring magnetization, magnetic susceptibility and electrical resistivity. Er 7 Rh 3 possesses antiferromagnetic state below T N = 13 K. In the ordered state, the two successive magnetic transitions at T t1 = 6.2 K and T t2 = 4.5 K were observed. Several field-induced magnetic transitions were also observed along the a- and c-axes below T N ; magnetic field H – temperature T phase diagram along the c-axis was constructed. The field-induced magnetic transitions in Er 7 Rh 3 can be explained by the magnetic structure with two magnetic propagation vectors which were derived by the previous neutron diffraction studies. Electrical resistivity shows humps just below the magnetic transition temperatures, T N and T t1 due to the super-zone gap formation at the Fermi level; these anomalies can also be described by the magnetic structure changes in Er 7 Rh 3

Structural patterns of the Lake Erçek Basin, eastern Anatolia (Turkey): evidence from single-channel seismic interpretation

Science.gov (United States)

Toker, Mustafa; Tur, Hüseyin

2017-11-01

This study presents an analysis of the single-channel high-resolution shallow seismic reflection data from Lake Erçek, eastern Anatolia, to provide key information on the deformational elements, on the fault patterns and on the overall tectonic structure of the Lake Erçek Basin. High-resolution seismic data reveal major structural and deformational features, including N-S trending normal faults and W-E trending reverse faults bounding the Lake Erçek Basin, basement highs and folded structures along the marginal sections of the lake. The N-S trending normal faults asymmetrically control the steep western margin and the gentle eastern deltaic section, while the W-E trending reverse faults appear at the northern and southern margins. The N-S trending normal faults, half-graben structure, and the gradual thickening of sediments in the Erçek Basin toward the fault scarps strongly suggest an extensional tectonic regime resulting from an N-S compression. The Erçek Basin is an extension-controlled depocenter; it is a relatively undeformed and flat-lying deep Basin, forming a typical example of the half-graben structure. The N-S trending normal faults appear to be currently active and control the lake center and the E-delta section, resulting in subsidence in the lake floor. In the N- and S-margins of the lake, there is evidence of folding, faulting and accompanying block uplifting, suggesting a significant N-S compressional regime that results in the reverse faulting and basement highs along the marginal sections. The folding and faulting caused strong uplift of the basement blocks in the N- and S- margins, subsequently exposing the shelf and slope areas. The exposed areas are evident in the erosional unconformity of the surface of the basement highs and thinned sediments. The tilted basement strata and subsequent erosion over the basement block highs suggest prominent structural inversion, probably long before the formation of the lake. New high-resolution seismic

Fabrication and evaluation of green-light emitting Ta2O5:Er, Ce co-sputtered thin films

Directory of Open Access Journals (Sweden)

K. Miura

2015-01-01

Full Text Available Erbium and cerium co-doped tantalum-oxide (Ta2O5:Er, Ce thin films were fabricated using radio-frequency co-sputtering of Ta2O5, Er2O3, and CeO2 for the first time. Enhanced green-light emission due to Er3+ that seems to be sensitized by Ce3+ was observed from the film annealed at 900 °C for 20 min. From XRD measurements of the films, the β-Ta2O5 (orthorhombic, δ-Ta2O5 (hexagonal, and (201 Ta2O5 phases seem to be very important for obtaining green PL from them. Such Ta2O5:Er, Ce co-sputtered films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel green-light-emitting devices, and they will also be used as multi-functional coating films that can work both as anti-reflection and down-conversion films for realizing high-efficiency silicon solar cells.

Influence of phosphorous precursors on spectroscopic properties of Er3+-activated SiO2-HfO2-P2O5 planar waveguides

International Nuclear Information System (INIS)

Vasilchenko, I; Carpentiero, A; Chiappini, A; Chiasera, A; Ferrari, M; Vaccari, A; Lukowiak, A; Righini, G C; Vereshagin, V

2014-01-01

(70-x)SiO 2 -30HfO 2 -xP 2 O 5 (x= 5, 10 mol %) glass planar waveguides activated by 0.5 mol% Er 3 + ions were prepared by sol-gel route. Several phosphorous precursors have been investigated for the synthesis of a dielectric stable sol useful for the realization of planar waveguides. The waveguides were investigated by different diagnostic techniques. The optical properties such as refractive index, thickness, number of propagating modes and attenuation coefficient were measured at 632.8 and 543.5 nm by prism coupling technique. Transmission measurements were carried out in order to assess the transparency of the deposited films. Photoluminescence measurements and lifetime decay curves of the Er 3 + transition (4 I 13/2 → 4 I 15/2 ) were performed in order to investigate the role of P 2 O 5

Magnetic instabilities in Er1-xYxCo3 studied by NMR

International Nuclear Information System (INIS)

Niki, H.; Fukumura, T.; Kinjou, H.; Kinjou, T.; Pieper, M.W.; Gratz, E.; Paul-Boncour, V.; Markosyan, A.S.

2006-01-01

The field dependence of 59 Co NMR in ferrimagnetic Er 1-x Y x Co 3 was measured up to 8T at 4.2K. For pure ErCo 3 in fields perpendicular to the c axis the resonance frequencies change discontinuously between 2 and 3T due to a field induced metamagnetic transition. The transition is characterized by rotations of Er and Co magnetic moments away from the easy c-axis. The angles between the Co moments and the c axis at x=0.1 are obtained. The easy axis is found to be along the c axis for x=0 and 0.1, and inclined from the c axis for x=0.3 and 0.5

Concentration dependent luminescence quenching of Er{sup 3+}-doped zinc boro-tellurite glass

Energy Technology Data Exchange (ETDEWEB)

Said Mahraz, Zahra Ashur; Sahar, M.R., E-mail: mrahim057@gmail.com; Ghoshal, S.K.; Reza Dousti, M.

2013-12-15

Understanding the mechanism of luminescence quenching in rare earth doped tellurite glass is an important issue. The Er{sup 3+}-doped boro-tellurite glasses with compositions 30B{sub 2}O{sub 3}+10ZnO+(60−x)TeO{sub 2}+xEr{sub 2}O{sub 3} (where x=0, 0.5, 1, 1.5 and 2 mol%) were prepared by melt quenching method. Structural and optical properties of the proposed glasses were characterized using XRD, FTIR, density, UV–vis-IR absorption and PL spectroscopy. The amorphous nature of these glasses was confirmed by XRD technique. The IR-spectrum reveals five absorption bands assigned to different B–O and Te–O vibrational groups. UV–vis-IR absorption spectrum exhibits seven absorption bands at 6553, 10,244, 12,547, 15,360, 19,230, 20,661 and 22,522 cm{sup −1} corresponding to {sup 4}I{sub 13/2}, {sup 4}I{sub 11/2}, {sup 4}I{sub 9/2}, {sup 4}F{sub 9/2}, {sup 2}H{sub 11/2}, {sup 4}F{sub 7/2} and {sup 4}F{sub 3/2} excited states of Er{sup 3+} ion respectively. The optical band gap energy (E{sub opt}) corresponding to the direct and indirect allowed transitions decreased, while the Urbach energy and cut-off wavelengths are increased by the introduction of Er{sup 3+} ions. The refractive index, density and phonon cut-off edge of the samples are increased and the molar volume decreased with the further addition of dopants. The Judd–Ofelt parameter (Ω{sub 2}) decreased from 5.73 to 3.13×10{sup −20} cm{sup 2} with the increase of erbium ions concentration from 0.5 to 2 mol%. The PL spectra show green emissions for the transition from {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} excited states to {sup 4}I{sub 15/2} ground state, which show strong quenching due to the addition of Er{sup 3+} ions. -- Highlights: • Er{sup 3+}-doped zinc boro-tellurite glass has been synthesized by melt quench method. • Spectroscopic properties dependent concentration is analyzed by different techniques. • Judd–Ofelt intensity parameter (Ω{sub 2}) decreased by increase in erbium

Bifunctional behavior of Er3+ ions as the sintering additive and the fluorescent agent in Er3+ single doped γ-AlON transparent ceramics

International Nuclear Information System (INIS)

Wang, Ying; Xie, Xiumin; Qi, Jianqi; Wang, Shanshan; Wei, Nian; Lu, Zhongwen; Chen, Xingtao; Lu, Tiecheng

2016-01-01

We report on the sintering promoting and fluorescent activator roles of Er 3+ in AlON:Er 3+ transparent ceramics prepared by pressureless sintering with Er 2 O 3 and AlON powder. There shows that the transparency of samples varied with the content of Er 2 O 3 additive. The AlON:Er 3+ ceramics showed upconversion luminescence peaking at 546 nm, 662 nm and 840 nm under the 980 nm excitation due to transition of 4 S 3/2 / 2 H 11/2 → 4 I 15/2 , 4 F 9/2 → 4 I 15/2 and 4 S 3/2 / 2 H 11/2 → 4 I 13/2 of Er 3+ ions, respectively. The infrared spectra exhibited strong emission at 1534 nm corresponds to 4 I 13/2 → 4 I 15/2 transition. The mechanism of the IR and visible emission bands in AlON:Er 3+ ceramics are discussed, which suggest it should be attractive for lighting and display devices applications.

Optical energy gaps and photoluminescence peaks of BaGa2S4:Er3+ and BaGa2Se4:Er3+ single crystals

International Nuclear Information System (INIS)

Choe, Sung-Hyu; Jin, Moon-Seog; Kim, Wha-Tek

2005-01-01

BaGa 2 S 4 :Er 3+ and BaGa 2 Se 4 :Er 3+ single crystals were grown by using the chemical transport reaction method. The optical energy gaps of the BaGa 2 S 4 :Er 3+ and the BaGa 2 Se 4 :Er 3+ single crystals were found to be 4.045 eV and 3.073 eV, respectively, at 11 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Sharp emission peaks were observed in the photoluminescence spectra of the single crystals and assigned to radiation recombination between split Stark levels of the Er 3+ ion.

Flux pinning properties of ErBa2Cu3Oy thin films with BaZrO3 nanorods

International Nuclear Information System (INIS)

Haruta, M; Fujiyoshi, T; Sueyoshi, T; Dezaki, K; Ichigosaki, D; Miyahara, K; Miyagawa, R; Mukaida, M; Matsumoto, K; Yoshida, Y; Ichinose, A; Horii, S

2006-01-01

ErBa 2 Cu 3 O y (ErBCO) thin films with BaZrO 3 (BZO) nanorods were prepared by a PLD method for an enhancement of the critical current density J c . The values of J c for the ErBCO thin film containing 1.5 wt% BZO (Er15) in magnetic fields are higher than those for the ErBCO thin film containing 0.5 wt% BZO (Er05). The peaks of J c have been observed in the angular dependence of J c in both the films when the magnetic field is applied parallel to the c-axis. It has been found that the peak is attributed to the flux pinning by BZO nanorods oriented parallel to the c-axis. The vortex glass-liquid transition temperature T g and the pinning parameter m were derived by fitting observed electric transport properties to the theoretical expression based on the percolation transition model. The value of T g of Er15 is higher than that of Er05. This result indicates that the vortex glass phase extends to a higher temperature region on increasing the fraction of BZO. The peak of m has been found in the magnetic field dependence. This fact is probably due to matching the density of BZO nanorods with that of fluxoids, which was confirmed by TEM observations

Thermal, Spectral and Laser Properties of Er3+:Yb3+:GdMgB₅O10: A New Crystal for 1.5 μm Lasers.

Science.gov (United States)

Huang, Yisheng; Yuan, Feifei; Sun, Shijia; Lin, Zhoubin; Zhang, Lizhen

2017-12-25

A novel laser crystal of Er 3+ :Yb 3+ :GdMgB₅O 10 with dimension of 26 × 16 × 12 mm³ was grown successfully from K₂Mo₃O 10 flux by the top seeded solution growth method. The thermal diffusivity and specific heat capacity were measured to calculate the thermal conductivity of the crystal. The absorption and fluorescence properties of the crystal at room temperature were investigated in detail. The Judd-Ofelt method was used to analyze the polarized absorption spectra. The emission cross-section of the ⁴I 13/2 →⁴I 15/2 transition was calculated by the Füchtbauer-Ladenburg formula and the relevant gain cross-sections were estimated. Continuous-wave laser output of 140 mW at 1569 nm with the slope efficiency of 17.8% was demonstrated in a plano-concave resonator. The results reveal that Er 3+ :Yb 3+ :GdMgB₅O 10 crystal is a promising material for 1.5 μm lasers.

Polar cap flow channel events: spontaneous and driven responses

Directory of Open Access Journals (Sweden)

P. E. Sandholt

2010-11-01

Full Text Available We present two case studies of specific flow channel events appearing at the dusk and/or dawn polar cap boundary during passage at Earth of interplanetary (IP coronal mass ejections (ICMEs on 10 January and 25 July 2004. The channels of enhanced (>1 km/s antisunward convection are documented by SuperDARN radars and dawn-dusk crossings of the polar cap by the DMSP F13 satellite. The relationship with Birkeland currents (C1–C2 located poleward of the traditional R1–R2 currents is demonstrated. The convection events are manifest in ground magnetic deflections obtained from the IMAGE (International Monitor for Auroral Geomagnetic Effects Svalbard chain of ground magnetometer stations located within 71–76° MLAT. By combining the ionospheric convection data and the ground magnetograms we are able to study the temporal behaviour of the convection events. In the two ICME case studies the convection events belong to two different categories, i.e., directly driven and spontaneous events. In the 10 January case two sharp southward turnings of the ICME magnetic field excited corresponding convection events as detected by IMAGE and SuperDARN. We use this case to determine the ground magnetic signature of enhanced flow channel events (the NH-dusk/By<0 variant. In the 25 July case a several-hour-long interval of steady southwest ICME field (Bz<0; By<0 gave rise to a long series of spontaneous convection events as detected by IMAGE when the ground stations swept through the 12:00–18:00 MLT sector. From the ground-satellite conjunction on 25 July we infer the pulsed nature of the polar cap ionospheric flow channel events in this case. The typical duration of these convection enhancements in the polar cap is 10 min.

Luminescence dosemeter of the Al{sub 2}O{sub 3}:Er,Yb

Energy Technology Data Exchange (ETDEWEB)

Goncalves, Katia A.; Ventieri, Alexandre; Bitencourt, Jose F.S. [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Eletrica; Mittani, Juan C.R.; Tatumi, Sonia H. [Faculdade de Tecnologia de Sao Paulo (CEETEPS), SP (Brazil)

2011-07-01

The present work deals with the thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) properties of {alpha}-Al{sub 2}O{sub 3}: Er,Yb obtained by sol gel process. Nanocrystals formations composed by Er{sub 2}O{sub 3}, Yb{sub 2}O{sub 3} and Yb{sub 3}Al{sub 5}O{sub 12} were observed by TEM images, EDS, electron beam diffraction and RXD, located at the surface of the alumina grains. The sample codoped with 1mol% of Er and 2 mol% of Yb supplied the best results for TL and OSL responses. The growth of the intensity of dosimetric TL peak at 205 deg C was linear with gamma radiation doses and the same behavior was observed in OSL growth curve. The luminescence fading of the sample after a dose of 5 Gy was found initially for a period of 30 days and minimum detectable dose measured for TL was 60.78 mGy and for OSL was 13.09 mGy. (author)

Identification of Λ-like systems in Er3+:Y2SiO5 and observation of electromagnetically induced transparency

International Nuclear Information System (INIS)

Baldit, E.; Bencheikh, K.; Monnier, P.; Briaudeau, S.; Levenson, J. A.; Crozatier, V.; Lorgere, I.; Bretenaker, F.; Le Goueet, J. L.; Guillot-Noeel, O.; Goldner, Ph.

2010-01-01

Electromagnetically induced transparency (EIT) is reported in a solid-state material doped with erbium ions. In this paper we introduce the spectroscopic investigations we have conducted in order to identify the adequate Λ-like three-level systems in Er 3+ :Y 2 SiO 5 crystal, relevant for the demonstration of EIT. These results pave the way for nonlinear and quantum optics applications based on EIT at the telecom wavelength around 1.5 μm.

Elastic Properties of Ho0.5Er0.5 Single Crystal

DEFF Research Database (Denmark)

Spichkin, Yu.I.; Bohr, Jakob; Tishin, A.M.

1996-01-01

The results of an investigation of the Young's modulus E and the interval friction Q-1 of a Ho0.5Er0.5 single crystal in the basal plane in the temperature range 4.2-400 K are reported. The measurements were carried out by the method of flexural autovibrations of a thin sample with sound frequency...... (3 kHz). The Young's modulus at 4.2 K was measured to be 154 GPa. From the obtained data the magnetic part of the Young's modulus and the Debye temperature theta-D=375 K were calculated. The anomalies on the Young's modulus and the interval friction temperature dependencies corresponding to magnetic...

RELAP5/MOD3.3 assessment against MSIV closure events in Krsko NPP

International Nuclear Information System (INIS)

Parzer, I.

2002-01-01

The paper presents RELAP5/MOD3.3 analysis of two abnormal events occurred in Krsko NPP originating from sudden closure of Main Steam Isolation Valve (MSIV). Both events occurred before the SG replacement in 2000, the first one in September 1995 and the second one in January 1997. Valuable plant data were obtained from real plant transients and the RELAP5 code assessment was performed. Recently the last frozen version RELAP5/MOD3.3 has been released, before merging with another best-estimate thermalhydraulic system code TRAC into an integrated code. It is thus of utmost importance to assess models built in RELAP5 code against real plant transients before the code merger. A full twoloop plant model, developed at Jozef Stefan Institute (JSI), has been used for the analyses. The model includes old Westinghouse D4 type steam generators (SGs) with assumed 18% Utubes plugged in both steam generators. In the first case a malfunction in the MSIV in SG-1 caused inadvertent valve closure, while in the second case the valve stem has been broken in the SG-2, which also caused sudden valve closure.(author)

Mechanism of inhibition of mouse Slo3 (KCa 5.1) potassium channels by quinine, quinidine and barium.

Science.gov (United States)

Wrighton, David C; Muench, Stephen P; Lippiat, Jonathan D

2015-09-01

The Slo3 (KCa 5.1) channel is a major component of mammalian KSper (sperm potassium conductance) channels and inhibition of these channels by quinine and barium alters sperm motility. The aim of this investigation was to determine the mechanism by which these drugs inhibit Slo3 channels. Mouse (m) Slo3 (KCa 5.1) channels or mutant forms were expressed in Xenopus oocytes and currents recorded with 2-electrode voltage-clamp. Gain-of-function mSlo3 mutations were used to explore the state-dependence of the inhibition. The interaction between quinidine and mSlo3 channels was modelled by in silico docking. Several drugs known to block KSper also affected mSlo3 channels with similar levels of inhibition. The inhibition induced by extracellular barium was prevented by increasing the extracellular potassium concentration. R196Q and F304Y mutations in the mSlo3 voltage sensor and pore, respectively, both increased channel activity. The F304Y mutation did not alter the effects of barium, but increased the potency of inhibition by both quinine and quinidine approximately 10-fold; this effect was not observed with the R196Q mutation. Block of mSlo3 channels by quinine, quinidine and barium is not state-dependent. Barium inhibits mSlo3 outside the cell by interacting with the selectivity filter, whereas quinine and quinidine act from the inside, by binding in a hydrophobic pocket formed by the S6 segment of each subunit. Furthermore, we propose that the Slo3 channel activation gate lies deep within the pore between F304 in the S6 segment and the selectivity filter. © 2015 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of The British Pharmacological Society.

Dental enamel cells express functional SOCE channels.

Science.gov (United States)

Nurbaeva, Meerim K; Eckstein, Miriam; Concepcion, Axel R; Smith, Charles E; Srikanth, Sonal; Paine, Michael L; Gwack, Yousang; Hubbard, Michael J; Feske, Stefan; Lacruz, Rodrigo S

2015-10-30

Dental enamel formation requires large quantities of Ca(2+) yet the mechanisms mediating Ca(2+) dynamics in enamel cells are unclear. Store-operated Ca(2+) entry (SOCE) channels are important Ca(2+) influx mechanisms in many cells. SOCE involves release of Ca(2+) from intracellular pools followed by Ca(2+) entry. The best-characterized SOCE channels are the Ca(2+) release-activated Ca(2+) (CRAC) channels. As patients with mutations in the CRAC channel genes STIM1 and ORAI1 show abnormal enamel mineralization, we hypothesized that CRAC channels might be an important Ca(2+) uptake mechanism in enamel cells. Investigating primary murine enamel cells, we found that key components of CRAC channels (ORAI1, ORAI2, ORAI3, STIM1, STIM2) were expressed and most abundant during the maturation stage of enamel development. Furthermore, inositol 1,4,5-trisphosphate receptor (IP3R) but not ryanodine receptor (RyR) expression was high in enamel cells suggesting that IP3Rs are the main ER Ca(2+) release mechanism. Passive depletion of ER Ca(2+) stores with thapsigargin resulted in a significant raise in [Ca(2+)]i consistent with SOCE. In cells pre-treated with the CRAC channel blocker Synta-66 Ca(2+) entry was significantly inhibited. These data demonstrate that enamel cells have SOCE mediated by CRAC channels and implicate them as a mechanism for Ca(2+) uptake in enamel formation.

Synthesis, crystal structure and electrical properties of A-site cation ordered BaErMn2O5 and BaErMn2O6

International Nuclear Information System (INIS)

Świerczek, Konrad; Klimkowicz, Alicja; Zheng, Kun; Dabrowski, Bogdan

2013-01-01

In this paper, we report on a synthesis procedure, structural and electrical properties of BaErMn 2 O 5 and BaErMn 2 O 6 , A-site double perovskites having layered arrangement of Ba and Er cations. These materials belong to a family of BaLnMn 2 O 5+δ oxides, which up to now were successfully synthesized for Ln=Y and La–Ho lanthanides. Up to our knowledge, this is the first report on the successful synthesis of BaErMn 2 O 5 and BaErMn 2 O 6 , yielding>95 wt% of the considered compounds. Structural characterization of the materials is given at room temperature, together with in situ XRD studies, performed during oxidation of BaErMn 2 O 5 in air, at elevated temperatures up to 500 °C. A complex structural behavior was observed, with oxidation process of BaErMn 2 O 5 occurring at around 300 °C. The oxidized BaErMn 2 O 6 shows a structural phase transition at about 225 °C. Results of structural studies are supported by thermogravimetric measurements of the oxidation process, performed in air, as well as reduction process, preformed in 5 vol% of H 2 in Ar. Additionally, isothermal oxidation/reduction cycles were measured at 500 °C, showing interesting properties of BaErMn 2 O 5+δ , from a point of view of oxygen storage technology. Electrical conductivity of BaErMn 2 O 5 is of the order of 10 −4 S cm −1 at room temperature and shows activated character on temperature with activation energy E a =0.30(1) eV. Positive sign of Seebeck coefficient for this material indicates holes as dominant charge carriers. Oxidized BaErMn 2 O 6 possesses much higher electrical conductivity, almost 0.2 S cm −1 at room temperature. Additional, about 10-fold increase of electrical conductivity, occurring in the vicinity of 225 °C for this material, can be associated with phase transition from charge/orbital-ordered insulator COI(CE) to paramagnetic metal PM phase. The highest conductivity for BaErMn 2 O 6 was measured near 500 °C and is almost equal to 40 S cm −1 , while

Epitaxial growth of Er, Ti doped LiNbO3 films prepared by sol-gel method

International Nuclear Information System (INIS)

Takahashi, Makoto; Yoshiga, Tsuyoshi; Kajitani, Naofumi; Takeda, Yuki; Sato, Shoji; Wakita, Koichi; Ohnishi, Naoyuki; Hotta, Kazutoshi; Kurachi, Masato

2006-01-01

Erbium (Er 3+ ) doped lithium niobate (LiNbO 3 ) thick films were deposited on z-cut congruent LiNbO 3 (LN) substrate by the sol-gel method from the 0.20 mol/dm 3 precursor solution containing various Er 3+ concentration and 0.10 mol/dm 3 poly(vinyl alcohol) (PVA), and their crystal characteristics were evaluated. The Er 3+ concentration in the LN film was controlled by the Er 3+ concentration in the starting solution. The orientation relationships between Er doped LN films and substrates were determined by X-ray diffraction, Raman spectroscopy, and transmission electron microscopy, and (006) oriented Er doped LN epitaxial layers with parallel epitaxial relationships could be grown on the z-cut LN wafer. Moreover, it was made clear from the electron beam diffraction measurements that the film came to be polycrystalline, when the Er concentration was over 3 mol%. The refractive index of Er-doped LN films decreased with increasing Er concentration. 1.5 mol% Ti: 1.0 mol% Er LN films, which acted as a waveguide, were prepared by our so-gel method. It showed the 1530 nm emission by 980 nm excitation, which was considered to be due to the Er 3+ corresponding to the 4 I 13/2 → 4 I 15/2 transition. (author)

Studies of the energy transfer processes from Er3+ and Ho3+ to Nd3+, Tb3+ or Eu3+ in LiYF4 crystal and ZBLAN glass for the laser media optimization operating near 3μm region

International Nuclear Information System (INIS)

Jagosich, Fabio Henrique

2006-01-01

The energy transfer processes (ET) from the 4 I 13/2 ; 4 I 11/2 levels of Er 3+ and 5 I 6 levels of Ho 3+ ions in LiYF 4 (YLF) crystal and ZBLAN glass to Nd 3+ , Tb 3+ or Eu 3+ deactivators ions were studied. The micro parameters of these energy transfer processes were determined using the overlap integral method, and showed that Eu 3+ ion is the best deactivator of the first excited state of the Ho 3+ in YLF, and Nd 3+ is the best deactivator of the Er 3+ in YLF and ZBLAN materials. The 1.5 and 2.7μm emissions of Er 3+ and 2.1 and 2.9μm fluorescence of Ho 3+ were measured using short laser pulses excitations from a tunable OPO pumped 2w-Nd:YAG laser system. We proposed a criterion for discriminating the energy transfer processes assisted by excitation migration (diffusion or hopping) among donors. It was observed that diffusion model describes the ET process from the second excited state of the donor (Er 3+ or Ho 3+ ) independently of the C D-D /C D-A ratio, while the hopping model can describe the ET process involving the first excited state of donor. We proposed a modification of the hopping model in order to describe the experimental results for systems having C D-D /C D-A ≥ 10. Using the ET parameters, we determined that the best systems for laser action at 3μm are the Ho:Eu:YLF, Ho:Nd:YLF and Er:Nd:YLF systems. On the other hand, we found that Er 3+ doped (1.5 mol%) ZBLAN glasses, single and co-doped with Nd 3+ , Tb 3+ or Eu 3+ , do not show potential for laser action at 2.8μm. The up-conversion processes were studied in Er:YLF systems as a function of the Er 3+ concentration, and the excited state absorption (ESA) and up conversion by energy transfer (ETU) processes were discriminated using a time resolved fluorescence decays. It was observed that 980 nm is the most convenient wavelength for pumping the Er:YLF system for quasi cw laser operation at 2.8μm. The pump-probe technique was used to investigate the lifetime effects in Er:YLF system showing

Synthesis and characterization of the novel rare earth orthophosphates Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Schildhammer, Daniel; Petschnig, Lucas L.; Fuhrmann, Gerda; Heymann, Gunter; Schottenberger, Herwig; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Tribus, Martina [Innsbruck Univ. (Austria). Inst. fuer Mineralogie und Petrographie

2016-02-01

The new mixed rare earth (RE) orthophosphates Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 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{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} crystallize in a zircon-type structure being isostructural with the rare earth orthophosphate YPO{sub 4}. Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} crystallize in the tetragonal space group I4{sub 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{sup 3}, R{sub p} = 0.0143, and R{sub wp} = 0.0186 (all data) for Y{sub 0.5}Er{sub 0.5}PO{sub 4} and a = 684.61(2), c = 599.31(2) pm, V = 0.28089(2) nm{sup 3}, R{sub p} = 0.0242, and R{sub wp} = 0.0313 (all data) for Y{sub 0.5}Yb{sub 0.5}PO{sub 4}. Furthermore, the structure of Y{sub 0.5}Er{sub 0.5}PO{sub 4} was refined from single-crystal X-ray diffraction data: a = 687.78(5), c = 601.85(4) pm, V = 0.28470(5) nm{sup 3}, R{sub 1} = 0.0165, and wR{sub 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{sub 4}]{sup 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{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} was additionally confirmed by single-crystal EDX spectroscopy revealing a ratio of 1:1.

Energy transfer upconversion in Er3+-Tm3+ codoped sodium silicate glass

Science.gov (United States)

Kumar, Vinod; Pandey, Anurag; Ntwaeaborwa, O. M.; Swart, H. C.

2018-04-01

Er3+/Tm3+ doped and codoped Na2O-SiO2-ZnO (NSZO) glasses were prepared by the conventional melt-quenching method. The amorphous nature of the prepared glasses was confirmed by the X-ray diffraction analysis. The optical absorption spectrum displayed several peaks, which correspond to Er3+ and Tm3+ dopant ions embedded into the NSZO glass. Both dopants experienced upconversion emission under 980 nm excitation. Efficient energy transfer from Er3+ to Tm3+ was observed in the co-doped samples to enhance the near infrared emission of the Tm3+ ions.

Synthesis and characterization of nanocomplexes of Eu(III) and Er(III) coordinate with 2(4-clorophenil)-3-phenyl-1,3,4-thiadiazoleo-5-tiolate mesoionic

International Nuclear Information System (INIS)

Taveira Rocha do Nascimento, Railda Shelsea; Rodrigues da Silva Morais, Crislene; Lucena Lira, Helio de; Alves de Morais, Soraya; Filgueiras de Athayde Filho, Petronio; Figueiredo Lopes Lucena, Luciana de; Gouveia de Souza, Antonio; Brasileiro Campos, Gabriela

2010-01-01

The solids achieved in nanometric scale have been demanding scientific and technological interest due to the significant alterations in physical and chemical properties observed in such kind of materials, potentializing their technological applications. The nanocomplexes produced by lanthanide ions with the mesoionic compounds 2(4-clorophenil)-3-phenyl-1,3,4-thiadiazole-5-tiolate (M-1) were achieved in a powdered yellowed way. These compounds were characterized through X-ray diffraction, infrared (IR) spectroscopy and differential scanning calorimetry (DSC). The X-ray diffractograms of the M-1 compound and of Er(M-1) 3 .3H 2 O, Eu(M-1) 3 .3H 2 O complexes, presented more than one phase and a crystalline structure. The disappearance and appearance of new peaks, as well as the variation on the intensity of the M-1 majoritary peaks as compared to the complexes' peaks can also be observed. The IR spectra indicate that the coordination of M-1 with the cations Eu +3 e Er +3 probably happens due to the sulfur exocyclic atom, where a considerable displacement in the carbon-sulfur (C-S)-ligation can be perceived. Comparing the DSC curves of the M-1, Er(M-1) 3 .3H 2 O and Eu(M-1) 3 .3H 2 O, a displacement of the complexes peaks in relation to M-1 can be observed, suggesting the achievement of new specimens. Thus, it can be concluded that the formation of two new organic nanocomplexes with crystalline characteristics which may be used as a pharmacy, is quite evident.

Spectroscopic properties of Yb3+ and Er3+ ions in heavy metal glasses

International Nuclear Information System (INIS)

Pisarski, Wojciech A.; Grobelny, Lukasz; Pisarska, Joanna; Lisiecki, Radoslaw; Ryba-Romanowski, Witold

2011-01-01

Highlights: → Heavy metal glasses doubly doped with Yb 3+ and Er 3+ were examined. → NIR luminescence at about 1530 nm and green and red up-conversion spectra were detected. → The unusual large spectral linewidth nearly close to 110 nm for 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in Yb-Er co-doped lead borate glass was obtained. → Long-lived NIR luminescence was detected in lead germanate glass. → The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host. - Abstract: Selected heavy metal glasses containing Yb 3+ and Er 3+ ions have been studied. Near-infrared luminescence spectra at 1.53 μm and up-conversion spectra of Er 3+ ions were registered under excitation of Yb 3+ ions by 975 nm diode laser line. The luminescence bands correspond to 4 I 13/2 - 4 I 15/2 (NIR), 4 S 3/2 - 4 I 15/2 (green) and 4 F 9/2 - 4 I 15/2 (red) transitions of Er 3+ , respectively. The optical transitions of rare earth ions have been examined as a function of glass host. The unusual large spectral linewidth nearly close to 110 nm for 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in Yb-Er co-doped lead borate glass was obtained, whereas long-lived NIR luminescence at 1.53 μm was detected in lead germanate glass. The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host, which was confirmed by FT-IR spectroscopy.

Luminescent and laser properties of Yb Er:GdCa4O(BO3)3: a new crystal for eye-safe 1.5-μm lasers

Science.gov (United States)

Denker, B.; Galagan, B.; Ivleva, L.; Osiko, V.; Sverchkov, S.; Voronina, I.; Hellstrom, J. E.; Karlsson, G.; Laurell, F.

2004-09-01

We present for the first time 1.5-μm laser emission in Yb Er:GdCa4O(BO3)3 (GdCOB). The crystals were grown by the Czochralski method from platinum crucibles. Spectroscopic and laser tests of the crystals are described. A continuous-wave output power of 80 mW was achieved in a monolithic microchip cavity under laser-diode pumping.

Impact of incoherent pumping field and Er3+ ion concentration on group velocity and index of refraction in an Er3+-doped YAG crystal

International Nuclear Information System (INIS)

Jafarzadeh, Hossein; Asadpour, Seyyed Hossein; Soleimani, H Rahimpour

2015-01-01

The effect of Er 3+ ion concentration and incoherent pumping field on the refractive index and group index in an Er 3+ : YAG crystal is investigated. It is shown that under different concentrations of Er 3+ ion in the crystal, the index of refraction and absorption can be changed and a high index of refraction is accompanied by amplification in the medium. Also, it is shown that with the switching from subluminal to superluminal, or vice versa, light propagation can be obtained by different concentrations of Er 3+ ions in the crystal. (paper)

Er{sub 1.33}Pt{sub 3}Ga{sub 8}: A modulated variant of the Er{sub 4}Pt{sub 9}Al{sub 24}-structure type

Energy Technology Data Exchange (ETDEWEB)

Oswald, Iain W.H. [Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080 (United States); Gourdon, Olivier [Research and Development, ZS Pharma, Coppell, TX 75109 (United States); Bekins, Amy; Evans, Jess [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019 (United States); Treadwell, LaRico J. [Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080 (United States); Chan, Julia Y., E-mail: Julia.Chan@utdallas.edu [Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080 (United States); Macaluso, Robin T., E-mail: robin.macaluso@uta.edu [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019 (United States); Department of Chemistry and Biochemistry, University of Northern Colorado, Greeley, CO 80639 (United States)

2016-10-15

Single crystals of Er{sub 1.33}Pt{sub 3}Ga{sub 8} were synthesized in a molten Ga flux. Er{sub 1.33}Pt{sub 3}Ga{sub 8} can be considered to be a modulated variant of the Er{sub 4}Pt{sub 9}Al{sub 24}-structure type, where the partial occupancies are ordered. Indeed, the presence of weak satellite reflections indicates a complex organization and distribution of the Er and Ga atoms within the [ErGa] slabs. The structure has been solved based on single crystal X-ray diffraction data in the monoclinic superspace group X2/m(0β0)00 with a commensurate modulated vector q=1/3b*. Precession images also indicate diffusion in the perpendicular direction indicating a partial disorder of this arrangement from layer to layer. In addition, Er{sub 1.33}Pt{sub 3}Ga{sub 8} shows antiferromagnetic ordering at T{sub N}~5 K. - Graphical abstract: A precession image of the hk0 zone showing weak, periodic, unindexed reflections indicating modulation and representation of the commensurate [ErGa] layer showing the waving modulated occupation. - Highlights: • Single crystals of Er{sub 1.33}Pt{sub 3}Ga{sub 8} were grown from gallium flux. • The structure of Er{sub 1.33}Pt{sub 3}Ga{sub 8} is compared to Er{sub 4}Pt{sub 9}Al{sub 24}. • Structure has been solved in the monoclinic superspace group X2/m(0β0)00 with a commensurate modulated vector q=1/3b*.

Investigation of thermal stability and spectroscopic properties in Er3+/Yb3+-codoped TeO2-Li2O-B2O3-GeO2 glasses.

Science.gov (United States)

Nie, Qiu-Hua; Gao, Yuan; Xu, Tie-Feng; Shen, Xiang

2005-06-01

The new Er3+/Yb3+ co-doped 70TeO2-5Li2O-(25-x)B2O3-xGeO2 (x = 0, 5, 10, 15 fand 20 mol.%) glasses were prepared. The thermal stability, absorption spectra, emission spectra and lifetime of the 4I(13/2) level of Er3+ ions were measured and studied. The FT-IR spectra were carried out in order to investigate the structure of local arrangements in glasses. It is found that the thermal stability, absorption cross-section of Yb3+, emission intensity and lifetime of the 4I(13/2) level of Er3+ increase with increasing GeO2 content in the glass composition, while the fluorescence width at half maximum (FWHM) at 1.5 um of Er3+ is about 70 nm. The obtained data suggest that this system glass can be used as a candidate host material for potential broadband optical amplifiers.

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

Science.gov (United States)

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

2016-09-01

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

Performance of a diode-pumped BaY2F8:Er3+(7.5 at.%) laser at 2.8-µm

NARCIS (Netherlands)

Wittwer, S.; Pollnau, Markus; Spring, R.; Lüthy, W.; Weber, H.P.; McFarlane, R.A.; Harder, Ch.; Meier, H.P.

1996-01-01

An Er3+-doped BaY2F8 laser crystal with a dopant concentration of 7.5 at.% is quasi-cw-pumped longitudinally with the combined beams of two diode lasers. The pump wavelength is 967 nm, the output wavelength ranges from 2.7 to 2.8 um. The dependence of slope efficiency and threshold power on the

Molecular determinants in TRPV5 channel assembly.

NARCIS (Netherlands)

Chang, Q.; Gyftogianni, E.; Graaf, K.F.J. van de; Hoefs, S.J.G.; Weidema, A.F.; Bindels, R.J.M.; Hoenderop, J.G.J.

2004-01-01

The epithelial Ca(2+) channels TRPV5 and TRPV6 mediate the Ca(2+) influx in 1,25-dihydroxyvitamin D(3)-responsive epithelia and are therefore essential in the maintenance of the body Ca(2+) balance. These Ca(2+) channels assemble in (hetero)tetrameric channel complexes with different functional

Molecular determinants in TRPV5 channel assembly

NARCIS (Netherlands)

Chang, Qing; Gyftogianni, Emmanouela; van de Graaf, Stan F. J.; Hoefs, Susan; Weidema, Freek A.; Bindels, René J. M.; Hoenderop, Joost G. J.

2004-01-01

The epithelial Ca(2+) channels TRPV5 and TRPV6 mediate the Ca(2+) influx in 1,25-dihydroxyvitamin D(3)-responsive epithelia and are therefore essential in the maintenance of the body Ca(2+) balance. These Ca(2+) channels assemble in (hetero)tetrameric channel complexes with different functional

Ikon. iPod er kongen over mp3. Hvad er hemmeligheden?

DEFF Research Database (Denmark)

Dickson, Thomas

2005-01-01

iPod er blevet ikonet for det 21. århundrede. Men iPod var hverken den første mp3-afspiller eller den første veldesignede af slagsen. Før iPod så dagens lys var Bang & Olufsen på banen med sin næsten lige så lækre BeoSound2.......iPod er blevet ikonet for det 21. århundrede. Men iPod var hverken den første mp3-afspiller eller den første veldesignede af slagsen. Før iPod så dagens lys var Bang & Olufsen på banen med sin næsten lige så lækre BeoSound2....

RELAP5/MOD 3.3 analysis of Reactor Coolant Pump Trip event at NPP Krsko

International Nuclear Information System (INIS)

Bencik, V.; Debrecin, N.; Foretic, D.

2003-01-01

In the paper the results of the RELAP5/MOD 3.3 analysis of the Reactor Coolant Pump (RCP) Trip event at NPP Krsko are presented. The event was initiated by an operator action aimed to prevent the RCP 2 bearing damage. The action consisted of a power reduction, that lasted for 50 minutes, followed by a reactor and a subsequent RCP 2 trip when the reactor power was reduced to 28 %. Two minutes after reactor trip, the Main Steam Isolation Valves (MSIV) were isolated and the steam dump flow was closed. On the secondary side the Steam Generator (SG) pressure rose until SG 1 Safety Valve (SV) 1 opened. The realistic RELAP5/MOD 3.3 analysis has been performed in order to model the particular plant behavior caused by operator actions. The comparison of the RELAP5/MOD 3.3 results with the measurement for the power reduction transient has shown small differences for the major parameters (nuclear power, average temperature, secondary pressure). The main trends and physical phenomena following the RCP Trip event were well reproduced in the analysis. The parameters that have the major influence on transient results have been identified. In the paper the influence of SG 1 relief and SV valves on transient results was investigated more closely. (author)

Crystal field in ErGa3 - a neutron spectroscopy study

International Nuclear Information System (INIS)

Murasik, A.; Czopnik, A.; Clementyev, E.; Schefer, J.

2000-01-01

The splitting of the J = 15/2 multiplet of Er in a cubic crystal field has been determined by inelastic scattering from a polycrystalline sample of ErGa 3 . On the base of observed intensities and their temperature variation we have been able to determine two crystal electric fields (CEF) parameters required for cubic symmetry. Least-squares fits of calculated crystal field transitions of the observed neutron inelastic scattering spectra taken at 12, 24, 32, 40, 50 and 80 K, gave the crystal field parameters: B 4 (7.15±0.05) x 10 -5 and B 6 = (1.28±0.05) x 1- -6 MeV yielding the Γ 7 doublet as a ground level with the overall splitting of 10.92 MeV. The results are used to calculate the temperature-depended zero field magnetization and the Schottky anomaly of the heat capacity of the ErGa 3 which yield reasonable agreement with experimental data obtained earlier. (author)

Bcl-2 associated athanogene 5 (Bag5) is overexpressed in prostate cancer and inhibits ER-stress induced apoptosis

International Nuclear Information System (INIS)

Bruchmann, Anja; Roller, Corinna; Walther, Tamara Vanessa; Schäfer, Georg; Lehmusvaara, Sara; Visakorpi, Tapio; Klocker, Helmut; Cato, Andrew C B; Maddalo, Danilo

2013-01-01

The Bag (Bcl-2 associated athanogene) family of proteins consists of 6 members sharing a common, single-copied Bag domain through which they interact with the molecular chaperone Hsp70. Bag5 represents an exception in the Bag family since it consists of 5 Bag domains covering the whole protein. Bag proteins like Bag1 and Bag3 have been implicated in tumor growth and survival but it is not known whether Bag5 also exhibits this function. Bag5 mRNA and protein expression levels were investigated in prostate cancer patient samples using real-time PCR and immunoblot analyses. In addition immunohistological studies were carried out to determine the expression of Bag5 in tissue arrays. Analysis of Bag5 gene expression was carried out using one-way ANOVA and Bonferroni’s Multiple Comparison test. The mean values of the Bag5 stained cells in the tissue array was analyzed by Mann-Whitney test. Functional studies of the role of Bag5 in prostate cancer cell lines was performed using overexpression and RNA interference analyses. Our results show that Bag5 is overexpressed in malignant prostate tissue compared to benign samples. In addition we could show that Bag5 levels are increased following endoplasmic reticulum (ER)-stress induction, and Bag5 relocates from the cytoplasm to the ER during this process. We also demonstrate that Bag5 interacts with the ER-resident chaperone GRP78/BiP and enhances its ATPase activity. Bag5 overexpression in 22Rv.1 prostate cancer cells inhibited ER-stress induced apoptosis in the unfolded protein response by suppressing PERK-eIF2-ATF4 activity while enhancing the IRE1-Xbp1 axis of this pathway. Cells expressing high levels of Bag5 showed reduced sensitivity to apoptosis induced by different agents while Bag5 downregulation resulted in increased stress-induced cell death. We have therefore shown that Bag5 is overexpressed in prostate cancer and plays a role in ER-stress induced apoptosis. Furthermore we have identified GRP78/BiP as a novel

(Dy0.5Er0.5)Al2: A large magnetocaloric effect material for low-temperature magnetic refrigeration

International Nuclear Information System (INIS)

Gschneidner, K.A. Jr.; Takeya, H.; Moorman, J.O.; Pecharsky, V.K.

1994-01-01

The low-temprature heat capacity and ac and dc magnetic properties of (Dy 0.5 Er 0.5 )Al 2 have been studied as a function of magnetic fields up to ∼10 T. The magnetocaloric effect in (Dy 0.5 Er 0.5 )Al 2 is 30% larger than that of the prototype material, GdPd. Magnetic measurements show that there is no measurable magnetic hysteresis above ∼17 K. These results suggest that (Dy 0.5 Er 0.5 )Al 2 would be a significantly better magnetic refrigerant than GdPd

Upconversion improvement in KLaF{sub 4}:Yb{sup 3+}/Er{sup 3+} nanoparticles by doping Al{sup 3+} ions

Energy Technology Data Exchange (ETDEWEB)

Zhou, Haifang [Fuzhou University, School of Physics and Information Engineering, and Institute of Micro-Nano Devices and Solar Cells, Fuzhou (China); Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou, Jiangsu (China); Wang, Xiechun; Lai, Yunfeng; Cheng, Shuying; Zheng, Qiao; Yu, Jinlin [Fuzhou University, School of Physics and Information Engineering, and Institute of Micro-Nano Devices and Solar Cells, Fuzhou (China)

2017-10-15

Rare-earth ion-doped upconversion (UC) materials show great potential applications in optical and optoelectronic devices due to their novel optical properties. In this work, hexagonal KLaF{sub 4}:Yb{sup 3+}/Er{sup 3+} nanoparticles (NPs) were successfully synthesized by a hydrothermal method, and remarkably enhanced upconversion luminescence in green and red emission bands in KLaF{sub 4}:Yb{sup 3+}/Er{sup 3+} NPs has been achieved by doping Al{sup 3+} ions under 980 nm excitation. Compared to the aluminum-free KLaF{sub 4}:Yb{sup 3+}/Er{sup 3+} NPs sample, the UC fluorescence intensities of the green and red emissions of NPs doped with 10 at.% Al{sup 3+} ions were significantly enhanced by 5.9 and 7.3 times, respectively. Longer lifetimes of the doped samples were observed for the {sup 4}S{sub 3/2} state and {sup 4}F{sub 9/2} state. The underlying reason for the UC enhancement by doping Al{sup 3+} ions was mainly ascribed to distortion of the local symmetry around Er{sup 3+} ions and adsorption reduction of organic ligands on the surface of NPs. In addition, the influence of doping Al{sup 3+} ions on the structure and morphology of the NPs samples was also discussed. (orig.)

RELAP5/MOD3.3 Analysis of the Loss of External Power Event with Safety Injection Actuation

Directory of Open Access Journals (Sweden)

Andrej Prošek

2018-01-01

Full Text Available The code assessment typically comprises basic tests cases, separate effects test, and integral effects tests. On the other hand, the thermal hydraulic system codes like RELAP5/MOD3.3 are primarily intended for simulation of transients and accidents in light water reactors. The plant measured data come mostly from startup tests and operational events. Also, for operational events the measured plant data may not be sufficient to explain all details of the event. The purpose of this study was therefore besides code assessment to demonstrate that simulations can be very beneficial for deep understanding of the plant response and further corrective measures. The abnormal event with reactor trip and safety injection signal actuation was simulated with the latest RELAP5/MOD3.3 Patch 05 best-estimate thermal hydraulic computer code. The measured and simulated data agree well considering the major plant system responses and operator actions. This suggests that the RELAP5 code simulation is good representative of the plant response and can complement not available information from plant measured data. In such a way, an event can be better understood.

Scintillation properties of Nd{sup 3+}, Tm{sup 3+}, and Er{sup 3+} doped LuF{sub 3} scintillators in the vacuum ultra violet region

Energy Technology Data Exchange (ETDEWEB)

Yanagida, Takayuki, E-mail: yanagida@imr.tohoku.ac.jp [New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Kawaguchi, Noriaki [Tokuyama Corporation Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 Japan (Japan); Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Fukuda, Kentaro [Tokuyama Corporation Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 Japan (Japan); Kurosawa, Shunsuke; Fujimoto, Yutaka; Futami, Yoshisuke; Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Taniue, Kojiro [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo, Kyoto, 606-8502 (Japan); Sekiya, Hiroyuki [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Hida, 506-1205 (Japan); Kubo, Hidetoshi [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo, Kyoto, 606-8502 (Japan); Yoshikawa, Akira [New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Tanimori, Toru [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo, Kyoto, 606-8502 (Japan)

2011-12-11

In order to develop novel vacuum ultra violet (VUV) emitting scintillators, we grew Nd 0.5%, Tm 0.5%, and Er 0.5% doped LuF{sub 3} scintillators by the {mu}-pulling down method, because LuF{sub 3} has a very wide band gap and Nd{sup 3+}, Tm{sup 3+}, and Er{sup 3+} luminescence centers show fast and intense 5d-4f emission in VUV region. Transmittance and X-ray induced radioluminescence were studied in these three samples using our original spectrometer made by Bunkou-Keiki company. In the VUV region, transmittance of 20-60% was achieved for all the samples. The emission peaks appeared at approximately 180, 165, and 164 nm for Nd{sup 3+}, Tm{sup 3+}, and Er{sup 3+} doped LuF{sub 3}, respectively. Using PMT R8778 (Hamamatsu), we measured their light yields under {sup 241}Am {alpha}-ray excitation. Compared with Nd:LaF{sub 3} scintillator, which has 33 photoelectrons/5.5 MeV {alpha}, Nd:LuF{sub 3} and Tm:LuF{sub 3} showed 900{+-}90 and 170{+-}20 ph/5.5 MeV-{alpha}, respectively. Only for the Nd doped one, we can detect {sup 137}Cs 662 keV {gamma}-ray photoabsorption peak and the light yield of 1200{+-}120 ph/MeV was measured. We also investigated their decay time profiles by picosecond pulse X-ray equipped streak camera, and the main decay component of Nd:LuF{sub 3} turned out to be 7.63 ns.

Interaction of Ce{sub 1−x}Er{sub x}O{sub 2−y} nanoparticles with Al{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Krajczyk, L.; Kraszkiewicz, P.; Kepinski, L., E-mail: L.Kepinski@int.pan.wroc.pl

2015-02-01

The interaction of nanocrystalline Ce{sub 0.5}Er{sub 0.5}O{sub 1.75} mixed oxide with an amorphous Al{sub 2}O{sub 3} in oxidizing and reducing atmosphere up to 1100 °C was studied by XRD, TEM, SEM-EDS and BET. Uniform, chemically homogeneous Ce{sub 0.5}Er{sub 0.5}O{sub 1.75} nanoparticles (2 nm in size) were prepared by microemulsion method and deposited on a high surface γ-alumina support. The nanoparticles were structurally and chemically stable in the oxidizing atmosphere up to 1100 °C, exhibiting only an increase of the mean crystallite size to 9 nm after 3 h treatment. Prolonged heating (24 h) at 1100 °C caused partial decomposition of the mixed oxide and reaction of the extracted erbium with the support with formation of hexagonal (P6{sub 3}/mmc) ErAlO{sub 3} aluminate. The same hexagonal ErAlO{sub 3} occurred also in Er/Al{sub 2}O{sub 3} sample prepared by impregnation of Al{sub 2}O{sub 3} support with an aqueous solution of Er nitrate and subjected to heating in air or hydrogen at 1100 °C. In the reducing atmosphere the Ce{sub 0.5}Er{sub 0.5}O{sub 1.75} reacted with Al{sub 2}O{sub 3} already at 800 °C, to form an amorphous surface phase. At 900 °C monoclinic (P2{sub 1}/c) (Er,Ce){sub 4}Al{sub 2}O{sub 9} mixed aluminate was formed with the unit cell volume 4.5% bigger than that of pure Er{sub 4}Al{sub 2}O{sub 9} phase. After 3 h treatment at 1000 °C more than half of the (Er,Ce){sub 4}Al{sub 2}O{sub 9} aluminate decomposed into two nanocrystalline mixed monoaluminates: tetragonal (I4/mcm) (Ce,Er)AlO{sub 3} and hexagonal (P6{sub 3}/mmc) (Er,Ce)AlO{sub 3}. Nanocrystalline mixed aluminate particles with Er{sup 3+} ions placed in well-defined lattice sites and supported at the surface of Al{sub 2}O{sub 3} support, may be interesting as highly efficient active components of optical waveguides amplifiers. - Graphical abstract: Structure evolution of Ce{sub 0.5}Er{sub 0.5}O{sub 1.75} on Al{sub 2}O{sub 3} in air and in H{sub 2}. - Highlights: �

RELAP5/MOD3 analysis of a heated channel in downflow

International Nuclear Information System (INIS)

Dimenna, R.A.; Qureshi, Z.H.; Boman, A.L.

1993-01-01

The onset of flow instability (OFI) is a significant phenomenon affecting the determination of a safe operating power limit in the Savannah River Site production reactors. Tests performed at Columbia University for a single tube with uniform axial and azimuthal heating have been analyzed with RELAP5/NPR, Version 0, a version of RELAP5/MOD3. The tests include water flow rates from 3.2 x l0 -4 - 2.l x 10 -3 m 3 /s (5 - 33 gpm), Reynolds numbers from 30,000 - 400,000, and surface heat fluxes from 0 - 3.2 x l0 6 w/m 2 (0 - 1,000,000 Btu/hr- ft 2 ). Pressure drop versus flow rate curves were mapped for both fixed pressure boundary conditions and fixed flow boundary conditions. RELAP5/MOD3 results showed fair agreement with data for both types of boundary conditions, and good internal consistency between calculations using the two different types of boundary conditions. Under single-phase unheated conditions, the code overpredicted the pressure drop by 22 - 34%. Under single-phase heated conditions, the overprediction increased to as much as 55%. For those tests where two-phase conditions were observed at the channel exit, RELAP5 predicted lower flows than seen in the tests before voiding occurred

The effects of energy transfer on the Er{sup 3+} 1.54 {mu}m luminescence in nanostructured Y{sub 2}O{sub 3} thin films with heterogeneously distributed Yb{sup 3+} and Er{sup 3+} codopants

Energy Technology Data Exchange (ETDEWEB)

Hoang, J.; Chang, J. P. [Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095 (United States); Schwartz, Robert N.; Wang, Kang L. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States)

2012-09-15

We report the effects of heterogeneous Yb{sup 3+} and Er{sup 3+} codoping in Y{sub 2}O{sub 3} thin films on the 1535 nm luminescence. Yb{sup 3+}:Er{sup 3+}:Y{sub 2}O{sub 3} thin films were deposited using sequential radical enhanced atomic layer deposition. The Yb{sup 3+} energy transfer was investigated for indirect and direct excitation of the Yb {sup 2}F{sub 7/2} state using 488 nm and 976 nm sources, respectively, and the trends were described in terms of Forster and Dexter's resonant energy transfer theory and a macroscopic rate equation formalism. The addition of 11 at. % Yb resulted in an increase in the effective Er{sup 3+} photoluminescence (PL) yield at 1535 nm by a factor of 14 and 42 under 488 nm and 976 nm excitations, respectively. As the Er{sub 2}O{sub 3} local thickness was increased to greater than 1.1 A, PL quenching occurred due to strong local Er{sup 3+}{r_reversible} Er{sup 3+} excitation migration leading to impurity quenching centers. In contrast, an increase in the local Yb{sub 2}O{sub 3} thickness generally resulted in an increase in the effective Er{sup 3+} PL yield, except when the Er{sub 2}O{sub 3} and Yb{sub 2}O{sub 3} layers were separated by more than 2.3 A or were adjacent, where weak Yb{sup 3+}{r_reversible} Er{sup 3+} coupling or strong Yb{sup 3+}{r_reversible} Yb{sup 3+} interlayer migration occurred, respectively. Finally, it is suggested that enhanced luminescence at steady state was observed under 488 nm excitation as a result of Er{sup 3+}{yields} Yb{sup 3+} energy back transfer coupled with strong Yb{sup 3+}{r_reversible} Yb{sup 3+} energy migration.

Spectroscopic properties of Er3+-doped fluorotellurite glasses containing various modifiers

Science.gov (United States)

Burtan-Gwizdała, Bożena; Reben, Manuela; Cisowski, Jan; Grelowska, Iwona; Yousef, El Sayed; Algarni, Hamed; Lisiecki, Radosław; Nosidlak, Natalia

2017-11-01

We have investigated the optical and spectroscopic properties of new Er3+-doped fluorotellurite glasses with the basic molar composition 75%TeO2-10%P2O5-10%ZnO-5%PbF2, modified by replacing 5%TeO2 by four various metal oxides, namely MgO, PbO, SrO and CdO. The ellipsometric data have provided a Sellmeier-type dispersion relation of the refractive index of the investigated glasses. The optical absorption edge has been described within the Urbach approach, while the absorption and fluorescence spectra have been analyzed in terms of the standard Judd-Ofelt theory along with the photoluminescence decay of the 4I13/2 and 4S3/2 levels of the Er3+ ion. The absorption and emission spectra of the 4I15/2 ↔ 4I13/2 infrared transition have been analyzed within the McCumber theory to yield the peak emission cross-section and figure of merit (FOM) for the amplifier gain. It appears that the glass containing MgO as a modifier is characterized by the largest FOM suggesting that the fluorotellurite matrix with this oxide can be a good novel host for Er3+ ion doping. Finally, we propose a new simple method to calculate the mean transition energy of the McCumber approach as the arithmetic average of the barycenter wavenumbers of absorption and emission spectra.

Involvement of TR3/Nur77 translocation to the endoplasmic reticulum in ER stress-induced apoptosis

International Nuclear Information System (INIS)

Liang Bin; Song Xuhong; Liu Gefei; Li Rui; Xie Jianping; Xiao Lifeng; Du Mudan; Zhang Qiaoxia; Xu Xiaoyuan; Gan Xueqiong; Huang Dongyang

2007-01-01

Nuclear orphan receptor TR3/Nur77/NGFI-B is a novel apoptotic effector protein that initiates apoptosis largely by translocating from the nucleus to the mitochondria, causing the release of cytochrome c. However, it is possible that TR3 translocates to other organelles. The present study was designed to determine the intracellular localization of TR3 following CD437-induced nucleocytoplasmic translocation and the mechanisms involved in TR3-induced apoptosis. In human neuroblastoma SK-N-SH cells and human esophageal squamous carcinoma EC109 and EC9706 cells, 5 μM CD437 induced translocation of TR3 to the endoplasmic reticulum (ER). This distribution was confirmed by immunofluorescence analysis, subcellular fractionation analysis and coimmunoprecipitation analysis. The translocated TR3 interacted with ER-targeting Bcl-2; initiated an early release of Ca 2+ from ER; resulted in ER stress and induced apoptosis through ER-specific caspase-4 activation, together with induction of mitochondrial stress and subsequent activation of caspase-9. Our results identified a novel distribution of TR3 in the ER and defined two parallel mitochondrial- and ER-based pathways that ultimately result in apoptotic cell death

Familial CJD Associated PrP Mutants within Transmembrane Region Induced Ctm-PrP Retention in ER and Triggered Apoptosis by ER Stress in SH-SY5Y Cells

Science.gov (United States)

Wang, Xin; Shi, Qi; Xu, Kun; Gao, Chen; Chen, Cao; Li, Xiao-Li; Wang, Gui-Rong; Tian, Chan; Han, Jun; Dong, Xiao-Ping

2011-01-01

Background Genetic prion diseases are linked to point and inserted mutations in the prion protein (PrP) gene that are presumed to favor conversion of the cellular isoform of PrP (PrPC) to the pathogenic one (PrPSc). The pathogenic mechanisms and the subcellular sites of the conversion are not completely understood. Here we introduce several PRNP gene mutations (such as, PrP-KDEL, PrP-3AV, PrP-A117V, PrP-G114V, PrP-P102L and PrP-E200K) into the cultured cells in order to explore the pathogenic mechanism of familial prion disease. Methodology/Principal Findings To address the roles of aberrant retention of PrP in endoplasmic reticulum (ER), the recombinant plasmids expressing full-length human PrP tailed with an ER signal peptide at the COOH-terminal (PrP-KDEL) and PrP with three amino acids exchange in transmembrane region (PrP-3AV) were constructed. In the preparations of transient transfections, 18-kD COOH-terminal proteolytic resistant fragments (Ctm-PrP) were detected in the cells expressing PrP-KDEL and PrP-3AV. Analyses of the cell viabilities in the presences of tunicamycin and brefeldin A revealed that expressions of PrP-KDEL and PrP-3AV sensitized the transfected cells to ER stress stimuli. Western blots and RT-PCR identified the clear alternations of ER stress associated events in the cells expressing PrP-KDEL and PrP-3AV that induced ER mediated apoptosis by CHOP and capase-12 apoptosis pathway. Moreover, several familial CJD related PrP mutants were transiently introduced into the cultured cells. Only the mutants within the transmembrane region (G114V and A117V) induced the formation of Ctm-PrP and caused the ER stress, while the mutants outside the transmembrane region (P102L and E200K) failed. Conclusions/Significance The data indicate that the retention of PrP in ER through formation of Ctm-PrP results in ER stress and cell apoptosis. The cytopathic activities caused by different familial CJD associated PrP mutants may vary, among them the mutants

Familial CJD associated PrP mutants within transmembrane region induced Ctm-PrP retention in ER and triggered apoptosis by ER stress in SH-SY5Y cells.

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Xin Wang

Full Text Available BACKGROUND: Genetic prion diseases are linked to point and inserted mutations in the prion protein (PrP gene that are presumed to favor conversion of the cellular isoform of PrP (PrP(C to the pathogenic one (PrP(Sc. The pathogenic mechanisms and the subcellular sites of the conversion are not completely understood. Here we introduce several PRNP gene mutations (such as, PrP-KDEL, PrP-3AV, PrP-A117V, PrP-G114V, PrP-P102L and PrP-E200K into the cultured cells in order to explore the pathogenic mechanism of familial prion disease. METHODOLOGY/PRINCIPAL FINDINGS: To address the roles of aberrant retention of PrP in endoplasmic reticulum (ER, the recombinant plasmids expressing full-length human PrP tailed with an ER signal peptide at the COOH-terminal (PrP-KDEL and PrP with three amino acids exchange in transmembrane region (PrP-3AV were constructed. In the preparations of transient transfections, 18-kD COOH-terminal proteolytic resistant fragments (Ctm-PrP were detected in the cells expressing PrP-KDEL and PrP-3AV. Analyses of the cell viabilities in the presences of tunicamycin and brefeldin A revealed that expressions of PrP-KDEL and PrP-3AV sensitized the transfected cells to ER stress stimuli. Western blots and RT-PCR identified the clear alternations of ER stress associated events in the cells expressing PrP-KDEL and PrP-3AV that induced ER mediated apoptosis by CHOP and caspase-12 apoptosis pathway. Moreover, several familial CJD related PrP mutants were transiently introduced into the cultured cells. Only the mutants within the transmembrane region (G114V and A117V induced the formation of Ctm-PrP and caused the ER stress, while the mutants outside the transmembrane region (P102L and E200K failed. CONCLUSIONS/SIGNIFICANCE: The data indicate that the retention of PrP in ER through formation of Ctm-PrP results in ER stress and cell apoptosis. The cytopathic activities caused by different familial CJD associated PrP mutants may vary, among them

Upconversion Properties of the Er-Doped Y2O3, Bi2O3 and Sb2O3 Nanoparticles Fabricated by Pulsed Laser Ablation in Liquid Media

International Nuclear Information System (INIS)

Zamiri Reza; Bahari-Poor Hamid-Reza; Zakaria Azmi; Jorfi Raheleh; Zamiri Golnoush; Rebelo Avito; Omar Akrajas Ali

2013-01-01

Er-doped Y 2 O 3 , Bi 2 O 3 and Sb 2 O 3 nanoparticles are synthesized using pulsed laser ablation in a liquid. Ceramic targets of Y 2 O 3 :Er 3+ , Bi 2 O 3 :Er 3+ and Sb 2 O 3 :Er 3+ for ablation process are prepared by standard solid-state reaction technique and ablation is carried out in 5-ml distilled water using nanosecond Q-switched Nd:YAG laser. The morphology and size of the fabricated nanoparticles are evaluated by transmission electron microscopy and the luminescence emission properties of the prepared samples are investigated under different excitation wavelengths

The regulation of ER export and Golgi retention of ST3Gal5 (GM3/GM4 synthase) and B4GalNAcT1 (GM2/GD2/GA2 synthase) by arginine/lysine-based motif adjacent to the transmembrane domain.

Science.gov (United States)

Uemura, Satoshi; Shishido, Fumi; Kashimura, Madoka; Inokuchi, Jin-ichi

2015-12-01

In the Golgi maturation model, the Golgi cisternae dynamically mature along a secretory pathway. In this dynamic process, glycosyltransferases are transported from the endoplasmic reticulum (ER) to the Golgi apparatus where they remain and function. The precise mechanism behind this maturation process remains unclear. We investigated two glycosyltransferases, ST3Gal5 (ST3G5) and B4GalNAcT1 (B4GN1), involved in ganglioside synthesis and examined their signal sequences for ER export and Golgi retention. Reports have suggested that the [R/K](X)[R/K] motif functions as an ER exporting signal; however, this signal sequence is insufficient in stably expressed, full-length ST3G5. Through further analysis, we have clarified that the (2)R(3)R(X)(5) (9)K(X)(3) (13)K sequence in ST3G5 is essential for ER export. We have named the sequence the R/K-based motif. On the other hand, for ER export of B4GN1, the homodimer formation in addition to the R/K-based motif is required for ER export suggesting the importance of unidentified lumenal side interaction. We found that ST3G5 R2A/R3A and K9A/K13A mutants localized not only in Golgi apparatus but also in endosomes. Furthermore, the amounts of mature type asparagine-linked (N)-glycans in ST3G5 R2A/R3A and K9A/K13A mutants were decreased compared with those in wild-type proteins, and the stability of the mutants was lower. These results suggest that the R/K-based motif is necessary for the Golgi retention of ST3G5 and that the retention is involved in the maturation of N-glycans and in stability. Thus, several basic amino acids located on the cytoplasmic tail of ST3G5 play important roles in both ER export and Golgi retention. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Absence of the ER Cation Channel TMEM38B/TRIC-B Disrupts Intracellular Calcium Homeostasis and Dysregulates Collagen Synthesis in Recessive Osteogenesis Imperfecta

Science.gov (United States)

Cabral, Wayne A.; Ishikawa, Masaki; Garten, Matthias; Makareeva, Elena N.; Sargent, Brandi M.; Weis, MaryAnn; Barnes, Aileen M.; Webb, Emma A.; Shaw, Nicholas J.; Ala-Kokko, Leena; Lacbawan, Felicitas L.; Högler, Wolfgang; Leikin, Sergey; Blank, Paul S.; Zimmerberg, Joshua; Eyre, David R.; Yamada, Yoshihiko; Marini, Joan C.

2016-01-01

Recessive osteogenesis imperfecta (OI) is caused by defects in proteins involved in post-translational interactions with type I collagen. Recently, a novel form of moderately severe OI caused by null mutations in TMEM38B was identified. TMEM38B encodes the ER membrane monovalent cation channel, TRIC-B, proposed to counterbalance IP3R-mediated Ca2+ release from intracellular stores. The molecular mechanisms by which TMEM38B mutations cause OI are unknown. We identified 3 probands with recessive defects in TMEM38B. TRIC-B protein is undetectable in proband fibroblasts and osteoblasts, although reduced TMEM38B transcripts are present. TRIC-B deficiency causes impaired release of ER luminal Ca2+, associated with deficient store-operated calcium entry, although SERCA and IP3R have normal stability. Notably, steady state ER Ca2+ is unchanged in TRIC-B deficiency, supporting a role for TRIC-B in the kinetics of ER calcium depletion and recovery. The disturbed Ca2+ flux causes ER stress and increased BiP, and dysregulates synthesis of proband type I collagen at multiple steps. Collagen helical lysine hydroxylation is reduced, while telopeptide hydroxylation is increased, despite increased LH1 and decreased Ca2+-dependent FKBP65, respectively. Although PDI levels are maintained, procollagen chain assembly is delayed in proband cells. The resulting misfolded collagen is substantially retained in TRIC-B null cells, consistent with a 50–70% reduction in secreted collagen. Lower-stability forms of collagen that elude proteasomal degradation are not incorporated into extracellular matrix, which contains only normal stability collagen, resulting in matrix insufficiency. These data support a role for TRIC-B in intracellular Ca2+ homeostasis, and demonstrate that absence of TMEM38B causes OI by dysregulation of calcium flux kinetics in the ER, impacting multiple collagen-specific chaperones and modifying enzymes. PMID:27441836

Absence of the ER Cation Channel TMEM38B/TRIC-B Disrupts Intracellular Calcium Homeostasis and Dysregulates Collagen Synthesis in Recessive Osteogenesis Imperfecta.

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Wayne A Cabral

2016-07-01

Full Text Available Recessive osteogenesis imperfecta (OI is caused by defects in proteins involved in post-translational interactions with type I collagen. Recently, a novel form of moderately severe OI caused by null mutations in TMEM38B was identified. TMEM38B encodes the ER membrane monovalent cation channel, TRIC-B, proposed to counterbalance IP3R-mediated Ca2+ release from intracellular stores. The molecular mechanisms by which TMEM38B mutations cause OI are unknown. We identified 3 probands with recessive defects in TMEM38B. TRIC-B protein is undetectable in proband fibroblasts and osteoblasts, although reduced TMEM38B transcripts are present. TRIC-B deficiency causes impaired release of ER luminal Ca2+, associated with deficient store-operated calcium entry, although SERCA and IP3R have normal stability. Notably, steady state ER Ca2+ is unchanged in TRIC-B deficiency, supporting a role for TRIC-B in the kinetics of ER calcium depletion and recovery. The disturbed Ca2+ flux causes ER stress and increased BiP, and dysregulates synthesis of proband type I collagen at multiple steps. Collagen helical lysine hydroxylation is reduced, while telopeptide hydroxylation is increased, despite increased LH1 and decreased Ca2+-dependent FKBP65, respectively. Although PDI levels are maintained, procollagen chain assembly is delayed in proband cells. The resulting misfolded collagen is substantially retained in TRIC-B null cells, consistent with a 50-70% reduction in secreted collagen. Lower-stability forms of collagen that elude proteasomal degradation are not incorporated into extracellular matrix, which contains only normal stability collagen, resulting in matrix insufficiency. These data support a role for TRIC-B in intracellular Ca2+ homeostasis, and demonstrate that absence of TMEM38B causes OI by dysregulation of calcium flux kinetics in the ER, impacting multiple collagen-specific chaperones and modifying enzymes.

Length and amino acid sequence of peptides substituted for the 5-HT3A receptor M3M4 loop may affect channel expression and desensitization.

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Nicole K McKinnon

Full Text Available 5-HT3A receptors are pentameric neurotransmitter-gated ion channels in the Cys-loop receptor family. Each subunit contains an extracellular domain, four transmembrane segments (M1, M2, M3, M4 and a 115 residue intracellular loop between M3 and M4. In contrast, the M3M4 loop in prokaryotic homologues is <15 residues. To investigate the limits of M3M4 loop length and composition on channel function we replaced the 5-HT3A M3M4 loop with two to seven alanine residues (5-HT3A-A(n = 2-7. Mutants were expressed in Xenopus laevis oocytes and characterized using two electrode voltage clamp recording. All mutants were functional. The 5-HT EC(50's were at most 5-fold greater than wild-type (WT. The desensitization rate differed significantly among the mutants. Desensitization rates for 5-HT3A-A(2, 5-HT3A-A(4, 5-HT3A-A(6, and 5-HT3A-A(7 were similar to WT. In contrast, 5-HT3A-A(3 and 5-HT3A-A(5 had desensitization rates at least an order of magnitude faster than WT. The one Ala loop construct, 5-HT3A-A(1, entered a non-functional state from which it did not recover after the first 5-HT application. These results suggest that the large M3M4 loop of eukaryotic Cys-loop channels is not required for receptor assembly or function. However, loop length and amino acid composition can effect channel expression and desensitization. We infer that the cytoplasmic ends of the M3 and M4 segments may undergo conformational changes during channel gating and desensitization and/or the loop may influence the position and mobility of these segments as they undergo gating-induced conformational changes. Altering structure or conformational mobility of the cytoplasmic ends of M3 and M4 may be the basis by which phosphorylation or protein binding to the cytoplasmic loop alters channel function.

Spectroscopic properties of Er3+ and Yb3+ co-doped glass ceramics containing SrF2 nanocrystals

International Nuclear Information System (INIS)

Qiao Xvsheng; Fan Xianping; Wang Minquan; Zhang Xianghua

2009-01-01

The spectroscopic properties of Er 3+ /Yb 3+ co-doped 50SiO 2 -10Al 2 O 3 -20ZnF 2 -20SrF 2 glass and glass ceramic containing SrF 2 nanocrystals were investigated. The formation of SrF 2 nanocrystals in the glass ceramic was confirmed by XRD. The oscillator strengths for several transitions of the Er 3+ ions in the glass ceramic have been obtained and the Judd-Ofelt parameters were then determined. The XRD result and Judd-Ofelt parameters suggested that Er 3+ and Yb 3+ ions had efficiently enriched in the SrF 2 nanocrystals in the glass ceramic. The lifetime of excited states has been used to reveal the surroundings of luminescent Er 3+ and Yb 3+ and energy transfer (ET) mechanism between Er 3+ and Yb 3+ . Much stronger upconversion luminescence and longer lifetime of the Er 3+ /Yb 3+ co-doped glass ceramic were observed in comparison with the Er 3+ /Yb 3+ co-doped glass, which could be ascribed to more efficient ET from Yb 3+ to Er 3+ due to the enrichment of Yb 3+ and Er 3+ and the shortening of the distance between lanthanide ions in the precipitated SrF 2 nanocrystals.

Evidence for s-channel single-top-quark production in events with one charged lepton and two jets at CDF.

Science.gov (United States)

Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Martínez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Vázquez, F; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

2014-06-13

We report evidence for s-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy sqrt[s] = 1.96 TeV using a data set that corresponds to an integrated luminosity of 9.4 fb(-1) collected by the Collider Detector at Fermilab. We select events consistent with the s-channel process including two jets and one leptonically decaying W boson. The observed significance is 3.8 standard deviations with respect to the background-only prediction. Assuming a top-quark mass of 172.5 GeV/c(2), we measure the s-channel cross section to be 1.41(-0.42)(+0.44) pb.

Proteolytic fragmentation of inositol 1,4,5-trisphosphate receptors: a novel mechanism regulating channel activity?

Science.gov (United States)

Wang, Liwei; Alzayady, Kamil J; Yule, David I

2016-06-01

Inositol 1,4,5-trisphosphate receptors (IP3 Rs) are a family of ubiquitously expressed intracellular Ca(2+) release channels. Regulation of channel activity by Ca(2+) , nucleotides, phosphorylation, protein binding partners and other cellular factors is thought to play a major role in defining the specific spatiotemporal characteristics of intracellular Ca(2+) signals. These properties are, in turn, believed pivotal for the selective and specific physiological activation of Ca(2+) -dependent effectors. IP3 Rs are also substrates for the intracellular cysteine proteases, calpain and caspase. Cleavage of the IP3 R has been proposed to play a role in apoptotic cell death by uncoupling regions important for IP3 binding from the channel domain, leaving an unregulated leaky Ca(2+) pore. Contrary to this hypothesis, we demonstrate following proteolysis that N- and C-termini of IP3 R1 remain associated, presumably through non-covalent interactions. Further, we show that complementary fragments of IP3 R1 assemble into tetrameric structures and retain their ability to be regulated robustly by IP3 . While peptide continuity is clearly not necessary for IP3 -gating of the channel, we propose that cleavage of the IP3 R peptide chain may alter other important regulatory events to modulate channel activity. In this scenario, stimulation of the cleaved IP3 R may support distinct spatiotemporal Ca(2+) signals and activation of specific effectors. Notably, in many adaptive physiological events, the non-apoptotic activities of caspase and calpain are demonstrated to be important, but the substrates of the proteases are poorly defined. We speculate that proteolytic fragmentation may represent a novel form of IP3 R regulation, which plays a role in varied adaptive physiological processes. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Antiferromagnetic ordering of Er2NiSi3 compound

International Nuclear Information System (INIS)

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

2014-01-01

Ternary intermetallics of the stoichiometric composition R 2 TX 3 , where, R = rare earth element, T = d-electron transition metal and X= p-electron element, crystallizes in hexagonal A1B 2 type crystal structure with space group P6/mmm. We report here the synthesis and basic magnetic properties of the compound Er 2 NiSi 3 . Paramagnetic to antiferromagnetic phase change occurs below 5.4 K for this compound. (author)

Study of absorption and IR-emission of Er3+, Dy3+, Tm3+ doped high-purity tellurite glasses

Science.gov (United States)

Motorin, S. E.; Dorofeev, V. V.; Galagan, B. I.; Sverchkov, S. E.; Koltashev, V. V.; Denker, B. I.

2018-04-01

A study of high-purity TeO2-ZnO based tellurite glasses doped with Er3+, Dy3+ or Tm3+ that could be used as laser media in the 2-3 μm spectral range is presented. The glasses are prepared by melting the oxides mixture inside a silica glass reactor in an atmosphere of purified oxygen. The low level of hydroxyl groups absorption allowed to measure correctly the luminescence decay characteristics of the dopants. The rare-earth ions absorption bands, the luminescence spectra and kinetic characteristics of emission from the levels 4I11/2, 4I13/2 of Er3+, 6H13/2 of Dy3+ and 3H4, 3H5, 3F4 of Tm3+ ions are investigated. The results confirm the high potential of tellurite glasses as an active media for bulk, planar waveguide and fiber lasers.

HIGH REPETITION RATE MICROCHIP ER3+,YB3+:YAL3(BO34 DIODE-PUMPED LASER

Directory of Open Access Journals (Sweden)

K. N. Gorbachenya

2012-01-01

Full Text Available Diode-pumped passively Q-switched microchip Er,Yb:YAl3(BO34 laser for range-finding has been demonstrated. By using a Co2+:MgAl2O4 as a saturable absorber TEM00–mode Q-switched average output power of 315 mW was demonstrated at 1522 nm with pulse duration of 5 ns and pulse energy of 5,25 μJ at a repetition rate of 60 kHz.

Neutron diffraction and magnetization studies of Tb0.5Er0.5 single crystal in an external magnetic field

International Nuclear Information System (INIS)

Kosugi, T.; Yamamoto, N.

1999-01-01

Complete text of publication follows. The rare earth Tb 0.5 Er 0.5 alloy exhibits a tilted helix at low temperatures [1]. However, the magnetic structures of Tb 0.5 Er 0.5 and the magnetization processes of the tilted helix are not clear. Neutron diffraction experiments in external magnetic fields and magnetization measurements of Tb 0.5 Er 0.5 single crystal have been performed. At zero magnetic field, the Tb 0.5 Er 0.5 alloy exhibited a normal helix below 170 K, a bunching normal helix below about 28 K, and finally a bunching tilted helix below about 25 K. Below about 60 K, the helical pitch 30 deg showed a lock-in feature. The magnetization measurements at low temperatures showed a four-step magnetic transition. The results are presented as a magnetic field-temperature (H-T) phase diagram. (author) [1] H. Fujii et al., J. Phys. Soc. Jpn. 50 (1981) 2939

Effect of fluence on the lattice site of implanted Er and implantation induced strain in GaN

CERN Document Server

Wahl, U; Decoster, S; Vantomme, A; Correi, J G

2009-01-01

A GaN thin film was implanted with 5 × 1014 cm−2 of 60 keV stable 166Er, followed by the implantation of 2 × 1013 cm−2 radioactive 167Tm (t1/2 = 9.3 d) and an annealing sequence up to 900 °C. The emission channeling (EC) technique was applied to assess the lattice location of Er following the Tm decay from the conversion electrons emitted by 167mEr, which showed that more than 50% of 167mEr occupies substitutional Ga sites. The results are briefly compared to a 167mEr lattice location experiment in a GaN sample not pre-implanted with 166Er. In addition, high-resolution X-ray diffraction (HRXRD) was used to characterize the perpendicular strain in the high-fluence implanted film. The HRXRD experiments showed that the Er implantation resulted in an increase of the c-axis lattice constant of the GaN film around 0.5–0.7%. The presence of significant disorder within the implanted region was corroborated by the fact that the EC patterns for off-normal directions exhibit a pronounced angular broadening of t...

Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb3+,Er3+ phosphors.

Science.gov (United States)

Cho, Youngho; Song, Si Won; Lim, Soo Yeong; Kim, Jae Hun; Park, Chan Ryang; Kim, Hyung Min

2017-03-08

Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated. A comprehensive understanding of upconversion photophysics has been significantly impeded because the number of photons incorporated in the process in different competitive pathways could not be resolved. Few convincing results to estimate the contribution of each of the two-, three-, and four-photon channels of near-infrared (NIR) energy have been reported in yielding upconverted visible luminescence. In this study, we present the energy upconversion process occurring in NaYF 4 :Yb 3+ ,Er 3+ phosphors as a function of excitation frequency and power density. We investigated the upconversion mechanism of lanthanide phosphors by comparing UV/VIS one-photon excitation spectra and NIR multi-photon spectra. A detailed analysis of minor transitions in one-photon spectra and luminescence decay enables us to assign electronic origins of individual bands in multi-photon upconversion luminescence and provides characteristic transitions representing the corresponding upconversion channel. Furthermore, we estimated the quantitative contribution of multiple channels with respect to irradiation power and excitation energy.

Study of broadband near-infrared emission in Tm3+-Er3+ codoped TeO2-WO3-PbO glasses.

Science.gov (United States)

Balda, R; Fernández, J; Fernández-Navarro, J M

2009-05-25

In this work, we report the near-infrared emission properties of Tm(3+)-Er(3+) codoped tellurite TeO(2)-WO(3)-PbO glasses under 794 nm excitation. A broad emission from 1350 to 1750 nm corresponding to the Tm(3+) and Er(3+) emissions is observed. The full width at half-maximum of this broadband increases with increasing [Tm]/[Er] concentration ratio up to a value of ~ 160 nm. The energy transfer between Tm(3+) and Er(3+) ions is evidenced by both the temporal behavior of the near-infrared luminescence and the effect of Tm3+ codoping on the visible upconversion of Er(3+) ions.

High multi-photon visible upconversion emissions of Er3+ singly doped BiOCl microcrystals: A photon avalanche of Er3+ induced by 980 nm excitation

International Nuclear Information System (INIS)

Li, Yongjin; Song, Zhiguo; Li, Chen; Wan, Ronghua; Qiu, Jianbei; Yang, Zhengwen; Yin, Zhaoyi; Yang, Yong; Zhou, Dacheng; Wang, Qi

2013-01-01

Under 980 nm excitation, high multi-photon upconversion (UC) emission from the 2 H 11/2 / 4 S 3/2 (green) and 4 F 9/2 (red) levels of Er 3+ ions were observed from Er 3+ singly doped BiOCl microcrystals. These high-energy excited states were populated by a three to ten photon UC process conditionally, which depended on the pump power density and the Er 3+ ion doping concentration, characterizing as a hetero-looping enhanced energy transfer avalanche UC process. UC emission lifetime and Raman analysis suggest that the unusual UC phenomena are initiated by the new and intense phonon vibration modes of BiOCl lattices due to Er 3+ ions doping

Spin rotation in ErGa{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Murasik, A. E-mail: amur@cyf.gov.pl; Czopnik, A. E-mail: czopnik@int.pan.wroc.pl; Keller, L. E-mail: lukas.keller@psi.ch; Fischer, P. E-mail: peter.fischer@psi.ch

2000-04-01

The magnetic phase diagram of ErGa{sub 3}, built up from bulk magnetisation data, shows in zero-applied magnetic field two successive transitions at T{sub 1}=2.6 and T{sub 2} congruent with 2.8 K, respectively. The magnetic ordering of ErGa{sub 3} examined by neutron diffraction, can be derived from the so-called {l_brace}((1)/(2)), ((1)/(2)), 0{r_brace} structure, i.e. one in which the successive antiparallel (1 1 0) sheets of spins have additionally superimposed on them a sinusoidal modulation parallel to the [1 0 0] axis. The temperature dependence of neutron diffraction diagrams studied on the single crystal, revealed in the range of (2.6-2.78) K an abrupt reorientation of the Er{sup 3+} spins from the nearly [1 1 0] direction, towards the [1 0 0] axis. In this way previously observed effect on the polycrystalline sample has been confirmed. This rotation can be attributed to the T{sub 1} transition found in the H-T magnetic phase diagram.

Spectroscopy and near infrared upconversion of Er{sup 3+}-doped TZNT glasses

Energy Technology Data Exchange (ETDEWEB)

Venkata Krishnaiah, K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Marques-Hueso, J. [Institute of Sensors, Signals and Systems & Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Suresh, K.; Venkataiah, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Richards, B.S. [Light Technology Institute (LTI), Karlsruhe Institute of Technology, Engesserstrasse 13, 76131 Karlsruhe (Germany); Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Jayasankar, C.K., E-mail: ckjaya@yahoo.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India)

2016-01-15

In this paper we report on the near infrared (NIR) upconversion (UC) and spectroscopic properties of erbium (Er{sup 3+})-doped TeO{sub 2}–ZnO–Nb{sub 2}O{sub 5}–TiO{sub 2} (TZNT) oxide glasses. Judd–Ofelt theory has been applied to investigate the intensity parameters (Ω{sub λ}, λ=2, 4 and 6) which are used to derive radiative properties of the fluorescent levels. The different glasses present high refractive indices, low dispersion and Abbe numbers, as determined by variable angle spectroscopic ellipsometry. Under 980 nm excitation, the NIR emission profile and full width at half maximum have been studied in a broad range of Er{sup 3+} concentrations (0.01–3.0 mol%). On the other side, NIR UC has been obtained by exciting at 1523 nm, showing an increase of the intensity with Er{sup 3+} ion density in the studied range. The decay curves of the {sup 4}I{sub 13/2} level exhibit single exponential nature for all the different concentrations. The lifetime of the {sup 4}I{sub 13/2} level has been found to decrease (3.73–1.20 ms) after an initial increase (3.65–3.73 ms) with increasing of Er{sup 3+} ion concentration. The TZNT samples show broadband UC emission at 1.0 µm, which match with the band gap of silicon. This reveals that the investigated glasses could find application in photonics, for example non-linear optics and photovoltaic’s. - Highlights: • The Er{sup 3+}:TZNT glasses have been synthesized and optically characterized. • Refractive index and Abbe number of the TZNT glasses were measured by Ellipsometry. • Near infrared emission (1400–1600 nm) has been obtained under 980 nm excitation. • Near infrared upconversion at 980 nm has been investigated under 1523 nm excitation.

The ER in 3D: a multifunctional dynamic membrane network.

Science.gov (United States)

Friedman, Jonathan R; Voeltz, Gia K

2011-12-01

The endoplasmic reticulum (ER) is a large, singular, membrane-bound organelle that has an elaborate 3D structure with a diversity of structural domains. It contains regions that are flat and cisternal, ones that are highly curved and tubular, and others adapted to form contacts with nearly every other organelle and with the plasma membrane. The 3D structure of the ER is determined by both integral ER membrane proteins and by interactions with the cytoskeleton. In this review, we describe some of the factors that are known to regulate ER structure and discuss how this structural organization and the dynamic nature of the ER membrane network allow it to perform its many different functions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Apical microinfiltration evaluation of radicular channels irradiated with Er:YAG laser in vitro; Avaliacao da microinfiltracao apical de condutos radiculares irradiados in vitro com laser de Er:YAG

Energy Technology Data Exchange (ETDEWEB)

Sebrao, Catia Cilene Nass

2003-07-01

It was evaluated, in vitro, the adaptation of the filling material (Sealer 2S{sup R}) to the root channels dentine walls treated using the endodontic technique and prepared with the Er:YAG laser, by the technique of infiltration of methylene blue dye. Using scanning electronic microscopy, the morphologic alteration of the root channel dentine was observed for one sample per studied group. Also, an evaluation of the temperature increase in the external surface of the root during the irradiations was performed for two samples per group. For each group of samples, with eleven roots each, two sub-groups had been considered: the dry, irradiated after completely dry with absorbent cones of paper, and the humid, where a cone of absorbent paper was applied for two seconds in the root canal, leaving them lightly humidified. Considering the used energies for the irradiations, the groups are: G1, control (without irradiation), G2-dry (100 mJ-10 Hz), G2-humid (100 mJ-10 Hz), G3-dry (140 mJ-6 Hz), G3-humid (140 mJ-6 Hz), G4-dry (180 mJ-6 Hz), and G4-humid (180 mJ-6 Hz). The results had shown that apical microinfiltration did not exhibit significant difference among groups. The highest increase in temperature was observed for the dry groups, with the maximum variation of temperature of 6.5 deg C. Under the scanning electronic microscopy analysis, the humid groups had presented cleaner surfaces than the dry groups. The G4-humid group presented extensive regions of fusion and resolidification of the dentine. (author)

Electronic and magnetic properties of R0.5A0.5MnO3 compounds (R=Gd, Dy, Ho, Er; A=Sr, Ca)

International Nuclear Information System (INIS)

Terai, T.; Sasaki, T.; Kakeshita, T.; Fukuda, T.; Saburi, T.; Kitagawa, H.; Kindo, K.; Honda, M.

2000-01-01

Electronic and magnetic properties of the perovskitelike compounds of R 0.5 A 0.5 MnO 3 (R=Gd, Dy, Ho, Er; A=Sr, Ca) have been studied by measuring lattice parameter, electrical resistivity, magnetic susceptibility, and magnetization. All the Sr-doped compounds show a transition from a paramagnetic insulator to a spin-glass-like insulator at T g , even though the manganite La 0.5 Ca 0.5 MnO 3 , with nearly the same tolerance factor t, have been shown by others, to have different transitions. On the other hand, all the Ca-doped compounds show a charge-ordering transition at T CO and show a transition from a paramagnetic insulator to a canted antiferromagnetic insulator and/or a spin-glass-like insulator at T CA below T CO . These transition temperatures decrease with decreasing t. In the compound of Gd 0.5 Ca 0.5 MnO 3 , the collapse of the charge ordering has been observed under a pulsed high magnetic field of 45 T at 4.2 K. On the other hand, in the compound of Gd 0.5 Sr 0.5 MnO 3 , the magnetization process depends on the strength of magnetic field. These electronic and magnetic properties depend not only on the tolerance factor but also the variance (second moment) of the A-site ion radii distribution

Structural, optical and photo thermal properties of Er3+:Y2O3 doped PMMA nanocomposite

Science.gov (United States)

Tabanli, Sevcan; Eryurek, Gonul

2018-02-01

Thermal decomposition technique was employed to synthesize of phosphors of yttria (Y2O3) doped with erbium (Er3+) ions. After the synthesized procedure, the nano-sized crystalline powders were annealed at 800oC for 24 h. Annealed powders were embedded in poly(methyl methacrylate) (PMMA) by free radical polymerization to fabricate nanocomposite polymer materials. The crystalline structure of the powder and doped PMMA nanocomposite samples were determined using X-ray diffraction technique. Scherrer's equation and the FW1/5/4/5M method were used to determine average crystalline size and grain size distributions, respectively. The spectroscopic properties of the powders and doped PMMA nanocomposites were studied by measuring the upconversion emission spectra under near-infrared laser excitation at room temperature. The laser-induced photo thermal behaviors of Er3+:Y2O3 nano-powders and doped PMMA nanocomposite were investigated using the fluorescence intensity ratio (FIR) technique.

Site of Er ions in silica layers codoped with Si nanoclusters and Er

International Nuclear Information System (INIS)

Pellegrino, P.; Garrido, B.; Arbiol, J.; Garcia, C.; Lebour, Y.; Morante, J.R.

2006-01-01

Silica layers implanted with Si and Er ions to various doses and annealed at 950 deg. C have been investigated by means of energy-filtered transmission electron microscopy (EFTEM) and high annular angle dark field (HAADF). EFTEM analysis reveals Si nanoclusters (Si-nc) with an average size around 3 nm for high Si content (15 at. %) whereas no clusters can be imaged for the lowest Si excess (5 at. %). Raman scattering supports that amorphous Si precipitates are present in all the samples. Moreover, the filtered images show that Er ions appear preferentially located outside the Si-nc. HAADF analysis confirms that the Er atoms form agglomerations of 5-10 nm size when the Er concentration exceeds 1x10 20 cm -3 . This observation correlates well with the reduction of the Er population excitable by Si nanoclusters, in the best case corresponding to 10% of the total. A suitable tuning of the annealing drastically reduces this deleterious effect

Energy transfer dynamics of Er3+/Nd3+ embedded SiO2-Al2O3-Na2CO3-SrF2-CaF2 glasses for optical communications

Science.gov (United States)

Gelija, Devarajulu; Kadathala, Linganna; Borelli, Deva Prasad Raju

2018-04-01

The fluorescence and upconversion studies of Er3+ doped and Er3+/Nd3+ co-doped silicate based oxyfluoride glasses have been systematically analyzed. The broad band NIR emissions (830-1700 nm), includes optical bands like O, E, S, C and L were observed in the Er3+-Nd3+ co-doped glasses. The NIR emission intensity peaks centered at 876, 1057, 1329 and 1534 nm were observed for the Er3+-Nd3+ co-doped glasses. In the co-doped samples the strongest emission intensity at 1534 nm increased up to 0.5 mol % and then decreased to 3.0 mol % of Nd3+ ions under the excitation of 980 nm. The upconversion studies of the co-doped samples were recorded under the excitation of 980 and 808 nm and found the upconversion emission peaks centered at 524, 530, 547, 590 and 656 nm. The energy transfer processes between the relevant excitation levels of Er3+ and Nd3+ ions and energy transfer efficiency were discussed. The obtained results indicate that Nd3+ can be an efficient sensitizer for Er3+ to enhance upconversion emission at green laser transition for sensors and NIR emission at 1534 nm for optical communication applications.

Diode pumped cascade Er:Y2O3 laser

International Nuclear Information System (INIS)

Sanamyan, T

2015-01-01

A cascade, diode-pumped, continuous wave (CW), dual-wavelength operation in a 0.5% Er 3+ :Y 2 O 3 cryogenic ceramic laser is demonstrated for the first time. The laser operates on cascaded Er ( 4 I 11/2   →   4 I 13/2   →   4 I 15/2 ) transitions and can deliver 24 and 13 W at 1.6 and 2.7 μm, respectively. The overall efficiency with respect to the absorbed ∼980 nm power was 62%. This is, to our best knowledge, the first demonstration of an efficient, high power, cascade, erbium laser achieved in bulk solid-state lasers. The analysis of the output power, the laser’s wavelengths and slope efficiency for each individual laser transition are presented for pure CW operation mode. Also presented are the temporal behaviors of each laser line as a function of pump pulse duration in the quasi-CW regime. (letter)

Down-conversion luminescence and its temperature-sensing properties from Er3+-doped sodium bismuth titanate ferroelectric thin films

Science.gov (United States)

Wang, Shanshan; Zheng, Shanshan; Zhou, Hong; Pan, Anlian; Wu, Guangheng; Liu, Jun-ming

2015-11-01

Here, we demonstrate outstanding temperature-sensing properties from Na0.5Bi0.49Er0.01TiO3 (NBT:Er) thin films. The perovskite phase for them is stable in the temperature range from 80 to 440 K. Interestingly, the Er doping enhances the ferroelectric polarization and introduces local dipolar, which are positive for temperature sensing. Pumped by a 488-nm laser, the NBT:Er thin films show strong green luminescence with two bands around 525 and 548 nm. The intensity ratio I 525/ I 548 can be used for temperature sensing, and the maximum sensitivity is about 2.3 × 10-3 K-1, higher than that from Er-doped silicon oxide. These suggest NBT:Er thin film is a promising candidate for temperature sensor.

Long afterglow property of Er"3"+ doped Ca_2SnO_4 phosphor

International Nuclear Information System (INIS)

Zhang, Dongyun; Shi, Mingming; Sun, Yiwen; Guo, Yunyun; Chang, Chengkang

2016-01-01

A novel green emitting long afterglow phosphor, Er"3"+ -doped Ca_2SnO_4 (Ca_2SnO_4:Er"3"+), was prepared successfully via a traditional high temperature solid–state reaction method. Its properties have been characterized and analyzed by utilizing x-ray diffraction (XRD), photoluminescence spectroscope (PLS), afterglow decay curve (ADC) and thermal luminescence spectroscope (TLS). Three main emission peaks of PLS locate at 524, 550 and 668 nm, corresponding to CIE chromaticity coordinates of x = 0.326, y = 0.6592. An optimal doping concentration of Er"3"+ of 2% was determined. The Ca_2SnO_4:Er"3"+ phosphors showed a typical triple-exponential afterglow decay behavior when the UV source was switched off. Thermal simulated luminescence study indicated that the persistent afterglow of Ca_2SnO_4:2 mol% Er"3"+ phosphors was generated by the suitable electron or hole traps which were resulted from the doping the Ca_2SnO_4 host with rare-earth ions (Er"3"+). - Highlights: • A novel green emitting long afterglow phosphor, Ca_2SnO_4:Er"3"+, was prepared. • An optimal doping concentration of Er"3"+ of 2% was determined. • After the UV source was turned off, the Ca_2SnO_4:Er"3"+ showed a typical triple-exponential afterglow decay behavior. • CIE chromaticity coordinates results confirmed a green light emitting of the Ca_2SnO_4:Er"3"+. • The persistent afterglow of the Ca_2SnO_4:Er"3"+ was attributed to suitable electron or hole traps.

NMR studies on magnetic properties of intermetallic compounds Er1-xYxCo3

International Nuclear Information System (INIS)

Niki, H.; Kinjo, T.; Yogi, M.; Pieper, M.W.; Gratz, E.; Markosyan, A.S.

2007-01-01

Field dependence of 59 Co NMR in ferrimagnetic Er 1-x Y x Co 3 was measured up to 8T at 4.2K using aligned powdered samples. For pure ErCo 3 in fields perpendicular to the c axis the resonance frequencies change discontinuously between 2 and 3T due to a field induced metamagnetic transition. The easy axis is found to be along the c axis for x=0 and 0.1. An average angle for the Co moments of 45+/-5 o from the c axis is obtained from field dependence of 59 Co NMR at x=0.3. Directions of Co moments are also found to be inclined from the c axis for x=0.5

Structural, thermal and spectroscopic properties of highly Er3+-doped novel oxyfluoride glasses for photonic application

Energy Technology Data Exchange (ETDEWEB)

Kesavulu, C.R. [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Sreedhar, V.B.; Jayasankar, C.K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Jang, Kiwan [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Shin, Dong-Soo [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung Soo, E-mail: ssyi@silla.ac.kr [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of)

2014-03-01

Graphical abstract: - Highlights: • Er{sup 3+}-doped novel oxyfluoride glasses have been prepared by melt quenching technique. • Structural, thermal and spectroscopic properties have been carried out. • SALSFEr glasses exhibit intense green and weak red emissions at 365 nm excitation. • Major laser transition for Er{sup 3+} ion in SALSFEr glasses is {sup 4}I{sub 13/2} → {sup 4}I{sub 15/2} (1.53 μm). • These results suggest the possibility of using SALSFEr glasses as photonic devices. - Abstract: The Er{sup 3+}-doped novel oxyfluoride glasses of composition (43 − x)SiO{sub 2}–10Al{sub 2}O{sub 3}–24LiF–23SrF{sub 2}–xEr{sub 2}O{sub 3}, where x = 1.0, 2.0, 4.0 and 6.0 mol%, have been prepared by conventional melt quenching technique and are characterized through X-ray diffraction (XRD), differential thermal analysis (DTA), Raman, Fourier transform infrared (FT-IR) analysis, optical absorption spectra, visible (vis) and near-infrared (NIR) emission spectra measurements. Judd–Ofelt (JO) intensity parameters (Ω{sub λ}, λ = 2, 4 and 6) have been derived from the absorption spectrum of 1.0 mol% Er{sub 2}O{sub 3} doped glass and are in turn used to calculate radiative properties for the important luminescent levels of Er{sup 3+} ions. The studied glasses show intense green and weak red visible emissions under 365 nm excitation. The decrease in visible emission intensities with concentration of Er{sup 3+} ions has been explained due to energy transfer processes between Er{sup 3+} ions. Upon excitation at 980 nm laser diode, an intense 1.53 μm NIR emission has been observed with the maximum full width at half maximum (FWHM) for Er{sup 3+}-doped oxyfluoride glasses. The higher Er{sup 3+} ion doping capability and relatively high gain and broad emission at 1.5 μm are the most notable features of these glasses to realize efficient short-length optical amplifiers.

Spectroscopic properties of Er{sup 3+}-doped antimony oxide glass

Energy Technology Data Exchange (ETDEWEB)

Ouannes, K.; Soltani, M.T. [Laboratoire de Physique Photonique et Nanomatériaux Multifonctionnels, Université de Biskra, BP 145 RP, 07000 Biskra (Algeria); Poulain, M. [UMR 6226 – Verres et Céramiques – Campus de Beaulieu, Université' de Rennes 1, 35042 Rennes (France); Boulon, G.; Alombert-Goget, G.; Guyot, Y.; Pillonnet, A. [Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne (France); Lebbou, K., E-mail: kheireddine.lebbou@univ-lyon1.fr [Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne (France)

2014-08-01

Highlight: • As a function of Er concentration, glasses corresponding to the 60Sb{sub 2}O{sub 3}–20WO{sub 3}–(19 − x) Na{sub 2}O–1Bi{sub 2}O{sub 3}, xEr{sub 2}O{sub 3} formula were prepared. The quantum efficiency shows that this glass could be promised for laser devices. - Abstract: Spectroscopic properties of Er{sup 3+} ions have been studied in the 60Sb{sub 2}O{sub 3}–20WO{sub 3}–19Na{sub 2}O–1Bi{sub 2}O{sub 3} (SWNB) glasses doped with 0.25 and 0.50 mol% Er{sub 2}O{sub 3} respectively. The Judd–Ofelt parameters measured from the absorption spectra have been used to calculate the radiative life-time (τ{sub r}) and the stimulated emission cross section. The low phonon energy, a reduced quenching effect and a high quantum efficiency of 90% for the 1.53 μm expected laser emission into pumping at 980 nm are in favor of promising material laser application.

Upconversion luminescence properties of Y2O3:Yb3+, Er3+ nanostructures

International Nuclear Information System (INIS)

De Gejihu; Qin Weiping; Zhang Jishen; Zhang Jishuang; Wang, Yan; Cao Chunyan; Cui Yang

2006-01-01

Cubic Y 2 O 3 nanostructures doped with Yb 3+ and Er 3+ ions were synthesized by a facile hydrothermal method. Three distinct shapes such as nanotubes, nanospheres and nanoflakes formed in the products by adjusting the pH value of reacting solution. Powder X-ray diffraction analyses indicate that all the three nanostructures are pure cubic phase, while electron microscopy measurements confirm the formation of different morphologies. These nanostructures exhibit strong visible upconversion luminescence under the excitation of a 978-nm diode laser. In Yb 3+ - and Er 3+ - codoped Y 2 O 3 nanocrystals, the relative intensity of green emission became stronger as the size and morphology of sample changed from tubes to flakes

Microwave hydrothermal synthesis and upconversion properties of Yb3+/Er3+ doped YVO4 nanoparticles.

Science.gov (United States)

Kshetri, Yuwaraj K; Regmi, Chhabilal; Kim, Hak-Soo; Lee, Soo Wohn; Kim, Tae-Ho

2018-05-18

Yb 3+ and Er 3+ doped YVO 4 (Yb 3+ /Er 3+ :YVO 4 ) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb 3+ /Er 3+ :YVO 4 nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to 2 H 11/2 , 4 S 3/2 to 4 I 15/2 and 4 F 9/2 to 4 I 15/2 transitions of Er 3+ respectively. The emission intensity is found to depend strongly on the concentration of Yb 3+ . The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.

Microwave hydrothermal synthesis and upconversion properties of Yb3+/Er3+ doped YVO4 nanoparticles

Science.gov (United States)

Kshetri, Yuwaraj K.; Regmi, Chhabilal; Kim, Hak-Soo; Wohn Lee, Soo; Kim, Tae-Ho

2018-05-01

Yb3+ and Er3+ doped YVO4 (Yb3+/Er3+:YVO4) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb3+/Er3+:YVO4 nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to 2H11/2, 4S3/2 to 4I15/2 and 4F9/2 to 4I15/2 transitions of Er3+ respectively. The emission intensity is found to depend strongly on the concentration of Yb3+. The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.

Upconversion properties of Er3+/Yb3+ co-doped TeO2-TiO2-K2O glasses.

Science.gov (United States)

Su, Fangning; Deng, Zaide

2006-01-01

The Er3+/Yb3+ co-doped TeO2-TiO2-K2O glasses were prepared by conventional melting procedures, and their upconversion spectra were performed. The dependence of luminescence intensity on the ratio of Yb3+/Er3+ was studied, and the relationship between green upconversion luminescence intensity and Er3+ concentration is discussed in detail. The 546 nm green upconversion luminescence intensity is optimised in the studied glasses either when the Yb3+/Er3+ ratio is 25/1 and Er3+ concentration is 0.1 mol%, or when the Yb3+/Er3+ ratio is 10/1 and Er3+ concentration is 0.15 mol%. These glasses could be one of the potential candidates for LD pumping microchip solid-state lasers.

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

Science.gov (United States)

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

2017-07-01

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

Operational durability of a giant ER valve for Braille display

Science.gov (United States)

Luning, Xu; Han, Li; Yufei, Li; Shen, Rong; Kunquan, Lu

2017-05-01

The compact configuration of giant ER (electrorheological) valves provides the possibility of realizing a full-page Braille display. The operational durability of ER valves is a key issue in fulfilling a Braille display. A giant ER valve was used to investigate the variations in pressure drops and critical pressure drops of the valves over a long period under some typical operational parameters. The results indicate that neither the pressure drops nor critical pressure drops of giant ER valves show apparent deterioration over a long period. Without ER fluid exchange, a blockage appears in the channel of the valve because the ER structures induced by an external electric field cannot be broken by the Brownian motion of hydraulic oil molecules when the external electric field is removed. Forcing ER fluid flow is an effective and necessary method to keep the channel of the valve unblocked. Thus the operational durability of the valve using giant ER fluids is able to meet the demands of Braille display.

Ionically conducting Er3+-doped DNA-based biomembranes for electrochromic devices

International Nuclear Information System (INIS)

Leones, R.; Fernandes, M.; Sentanin, F.; Cesarino, I.; Lima, J.F.; Zea Bermudez, V. de; Pawlicka, A.; Magon, C.J.; Donoso, J.P.; Silva, M.M.

2014-01-01

Biopolymer-based membranes have particular interest due to their biocompatibility, Biodegradability, easy extraction from natural resources and low cost. The incorporation of Er 3+ ions into natural macromolecule hosts with the purpose of producing highly efficient emitting phosphors is of widespread interest in materials science, due to their important roles in display devices. Thus, biomembranes may be viewed as innovative materials for the area of optics. This paper describes studies of luminescent material DNA-based membranes doped with erbium triflate and demonstrates that their potential technological applications may be expanded to electrochromic devices. The sample that exhibits the highest ionic conductivity is DNA 10 Er, (1.17 × 10 −5 and 7.76 × 10 −4 S.cm −1 at 30 and 100 °C, respectively). DSC, XRD and POM showed that the inclusion of the guest salt into DNA does not change significantly its amorphous nature. The overall redox stability was ca. 2.0 V indicating that these materials have an acceptable stability window for applications in solid state electrochemical devices. The EPR analysis suggested that the Er 3+ ions are distributed in various environments. A small ECD comprising a Er 3+ -doped DNA-based membrane was assembled and tested by cyclic voltammetry and chronoamperometry. These electrochemical analyses revealed a pale blue color to transparent color change and a decrease of the charge density from -4.0 to -1.2 mC.cm −2 during 4000 color/bleaching cycles

Optical Amplification at 1525 nm in BaYF5: 20% Yb3+, 2% Er3+ Nanocrystals Doped SU-8 Polymer Waveguide

Directory of Open Access Journals (Sweden)

Pengcheng Zhao

2014-01-01

Full Text Available We demonstrated optical amplification in BaYF5: 20% Yb3+, 2% Er3+ (BYF nanocrystals doped polymer waveguide. BYF nanocrystals with an average size of ∼13 nm were synthesized by a high-boiling solvent process. Intense 1.53 μm fluorescence was obtained in the nanocrystals under excitation at 980 nm. An optical polymer waveguide was fabricated by using BYF nanocrystals doped SU-8 polymer as the core material. A relative optical gain of ∼10.4 dB at 1525 nm was achieved in a 1.1 cm long waveguide for an input signal power of ∼0.09 mW and a pump power of ∼212 mW.

Studies of the energy transfer processes from Er{sup 3+} and Ho{sup 3+} to Nd{sup 3+}, Tb{sup 3+} or Eu{sup 3+} in LiYF{sub 4} crystal and ZBLAN glass for the laser media optimization operating near 3{mu}m region; Estudos dos processos de transferencia de energia dos ions de Er{sup 3+} e Ho{sup 3+} para os ions de Nd{sup 3+}, Tb{sup 3+} e Eu{sup 3+} no cristal de LiYF{sub 4} e no vidro ZBLAN para a otimizacao de meios laser ativos que operam na regiao de 3{mu}m

Energy Technology Data Exchange (ETDEWEB)

Jagosich, Fabio Henrique

2006-07-01

The energy transfer processes (ET) from the {sup 4}I{sub 13/2}; {sup 4}I{sub 11/2} levels of Er{sup 3+} and {sup 5}I{sub 6} levels of Ho{sup 3+} ions in LiYF{sub 4} (YLF) crystal and ZBLAN glass to Nd{sup 3+}, Tb{sup 3+} or Eu{sup 3+} deactivators ions were studied. The micro parameters of these energy transfer processes were determined using the overlap integral method, and showed that Eu{sup 3+} ion is the best deactivator of the first excited state of the Ho{sup 3+} in YLF, and Nd{sup 3+} is the best deactivator of the Er{sup 3+} in YLF and ZBLAN materials. The 1.5 and 2.7{mu}m emissions of Er{sup 3+} and 2.1 and 2.9{mu}m fluorescence of Ho{sup 3+} were measured using short laser pulses excitations from a tunable OPO pumped 2w-Nd:YAG laser system. We proposed a criterion for discriminating the energy transfer processes assisted by excitation migration (diffusion or hopping) among donors. It was observed that diffusion model describes the ET process from the second excited state of the donor (Er{sup 3+} or Ho{sup 3+}) independently of the C{sub D-D}/C{sub D-A} ratio, while the hopping model can describe the ET process involving the first excited state of donor. We proposed a modification of the hopping model in order to describe the experimental results for systems having C{sub D-D}/C{sub D-A} {>=} 10. Using the ET parameters, we determined that the best systems for laser action at 3{mu}m are the Ho:Eu:YLF, Ho:Nd:YLF and Er:Nd:YLF systems. On the other hand, we found that Er{sup 3+} doped (1.5 mol%) ZBLAN glasses, single and co-doped with Nd{sup 3+}, Tb{sup 3+} or Eu{sup 3+}, do not show potential for laser action at 2.8{mu}m. The up-conversion processes were studied in Er:YLF systems as a function of the Er{sup 3+} concentration, and the excited state absorption (ESA) and up conversion by energy transfer (ETU) processes were discriminated using a time resolved fluorescence decays. It was observed that 980 nm is the most convenient wavelength for pumping the Er

Temperature effects on the growth and electrical properties of Er{sub 2}O{sub 3} films on Ge substrates

Energy Technology Data Exchange (ETDEWEB)

Ji, T.; Nie, T.X.; Cui, J. [State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433 (China); Fang, Z.B. [Department of Physics, Shaoxing University, Shaoxing 312000 (China); Yang, X.J.; Fan, Y.L.; Zhong, Z.Y. [State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433 (China); Jiang, Z.M., E-mail: zmjiang@fudan.edu.cn [State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433 (China)

2012-02-01

Er{sub 2}O{sub 3} films were grown on Ge (001) substrates at different temperatures by molecular beam epitaxy using metallic Er and molecular oxygen sources with otherwise identical conditions. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the microstructures and compositions of the films. The film deposited at room temperature is found to be composed of an Er{sub 2}O{sub 3} layer and an ErGe{sub x}O{sub y} interface layer with a thickness of 5.5 nm; the film grown at 300 Degree-Sign C has a mixed structure of Er{sub 2}O{sub 3} and ErGe{sub x}O{sub y} and the thickness was found to be reduced to 2.2 nm; the film grown at 450 Degree-Sign C becomes much rougher with voids formed underneath the film, having a mixed structure of three compounds of Er{sub 2}O{sub 3}, GeO and ErGe{sub x}O{sub y}. The growth mechanisms of the films at different temperatures are suggested. Current images obtained by tunneling atomic force microscopy show that the film grown at 450 Degree-Sign C has much more leaky spots than those grown at RT and 300 Degree-Sign C, which may arise from the formation of volatile GeO in the film.

The ER in 3-D: a multifunctional dynamic membrane network

OpenAIRE

Friedman, Jonathan R.; Voeltz, Gia K.

2011-01-01

The endoplasmic reticulum (ER) is a large, singular, membrane-bound organelle that has an elaborate 3-D structure with a diversity of structural domains. It contains regions that are flat and cisternal, ones that are highly curved and tubular, and others adapted to form contact with nearly every other organelle and with the plasma membrane. ER 3-D structure is determined by both integral ER membrane proteins and by interactions with the cytoskeleton. Here, we describe some of the factors that...

Search for isobar-analog states of superheavy hydrogen isotopes5-7He

Science.gov (United States)

Chernyshev, B. A.; Gurov, Yu B.; Korotkova, L. Yu; Kuznetsov, D. S.; Lapushkin, S. V.; Tel'kushev, M. V.; Schurenkova, T. D.

2016-02-01

Search for isobar-analog states (IAS) of superheavy hydrogen isotopes 5-7H was performed among the high-excited states of helium isotopes 5-7He. The excited spectra were measured in stopped pion absorption by light nuclei. The experiment was performed at low energy pion channel of LANL with two-arm multilayer semiconductor spectrometer. Excited states of 5-7He were observed in three-body reaction channels on 10,11B nuclei. Several excited levels were observed for the first time. 6He excited state with Ex = 27.0(8) MeV observed in 10B(π-,pt)X channel is an IAS candidate for 6H with Er ∼ 5.5 MeV. 7He excited state with Ex = 24.8(4) MeV observed in 10B(π-,pd)X, nB(π-,pt)X and nB(π-,dd)X channels is an IAS candidate for 7H with Er ∼ 3 MeV.

Magnetic properties of ErGa3

International Nuclear Information System (INIS)

Murasik, A.; Czopnik, A.; Keller, L.; Fischer, P.

1999-01-01

Bulk magnetization measurements and magnetic phase diagram for ErGa 3 show that zero-external magnetic field it undergoes two successive transitions at T 1 = 2.6 K and T 2 = 2.8 K, respectively. Its magnetic ordering examined by neutron diffraction, can be derived from the so-called [1/2, 1/2, 0] structure, i.e. one in which the successive antiparallel (110) sheets of spins have additionally superimposed on them a sinusoidal modulation parallel to the [100] axis. The temperature dependence of neutron diffraction diagrams studied with powder and single crystal samples revealed, that in the range of (2.6 - 2.78) k there occurs an abrupt reorientation of the Er 3+ spins from the [110]-type direction, towards the [100] axis. This rotation can be attributed to the T 1 transition found in the magnetic phase diagram. (author)

Co-operative energy transfer in Yb3+-Er3+ co-doped SrGdxOy upconverting phosphor

Science.gov (United States)

Kumar, Ashwini; Pathak, Trilok K.; Dhoble, S. J.; . Terblans, J. J.; Swart, H. C.

2018-04-01

Upconversion nanoparticles (UCNPs) have shown considerable interest in many fields; however, low upconversion efficiency of UCNPs is still the most severe limitation of their applications. Yb3+ and Er3+ co-doped SrGd4O7/Gd2O3(SGO) upconversion (UC) phosphors were synthesized by a modified co-precipitation process. The UC properties were investigated by direct excitation with a 980 nm laser. It was observed that the as prepared materials showed relatively strong green emission, while upon the incorporation of the Er3+ ion, there was an increase in the upconversion luminescence intensity for the red component. The effect of different doping concentration of Er3+on the emission spectra and X-ray diffraction patterns of the UC materials have also been studied. The luminescence lifetimes and Commission Internationale de L'Eclairage coordinates for these as prepared samples were determined to understand the energy transfer (ET) mechanisms occurring between Yb3+ and Er3+ in the SGO host matrix. The UC luminescence intensity as a function of laser pump power was monitored and it was confirmed that the UC process in SGO:Yb3+/Er3+is a two-photon absorption process. The findings reported here are expected to provide a better approach for understanding of the ET mechanisms in the oxide based Yb3+/Er3+ co-doped UC phosphors. This study might be helpful in precisely defined applications where optical transitions are essential criterion and this can be easily achieved by smart tuning of the emission properties of Yb3+/Er3+ co-doped UC phosphors.

Judd-Ofelt analysis and photoluminescence properties of RE3+ (RE = Er & Nd): Cadmium lithium boro tellurite glasses

Science.gov (United States)

Raju, K. Vemasevana; Raju, C. Nageswara; Sailaja, S.; Reddy, B. Sudhakar

2013-01-01

Rare earth (Er3+ and Nd3+) ions doped cadmium lithium boro tellurite (CLiBT) glasses were prepared by melt quenching method. The vis-NIR absorption spectra of these glasses have been analyzed systematically. Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) have been evaluated and used to compute the radiative properties of emission transitions of Er3+ and Nd3+: CLiBT glasses. From the NIR emission spectra of Er3+: CLiBT glasses a broad emission band centered at 1538 nm (4I13/2 → 4I15/2) is observed and from Nd3+: CLiBT glasses, three NIR emission bands at 898 nm (4F3/2 → 4I9/2), 1070 nm (4F3/2 → 4I11/2) and 1338 nm (4F3/2 → 4I13/2) are observed with an excitation wavelength λexci = 514.5 nm (Ar+ Laser). The FWHM and stimulated emission cross-section values are calculated for Er3+ and Nd3+: CLiBT glasses. FWHM × σeP values are also calculated for Er3+: CLiBT glasses.

Investigations on structural and optical behavior of Er3+ doped lead boro-tellurite glasses

Science.gov (United States)

Karthikeyan, P.; Suthanthirakumar, P.; Vijayakumar, R.; Marimuthu, K.

2015-06-01

Er3+ doped lead boro-tellurite glasses with the chemical composition (30-x)B2O3+30TeO2+23MgO+17PbF2+xEr2O3 (where x=0.05, 0.25, 0.5, and 1 in wt%) were synthesized by melt quenching technique. The structural and optical behaviors have been investigated through FTIR, absorption and emission spectral analysis. The UV-vis- NIR absorption spectra were used to calculate the bonding parameters (β ¯, δ), Judd-Ofelt intensity parameters (Ωλ, λ = 2, 4 and 6), Optical band gap and Urbach's energy of the prepared glasses. The radiative properties such as transition probability (AR), stimulated emission cross-section (σPE ), branching ratios (βR) were calculated from the luminescence spectra. The optical properties of the prepared glasses with varying Er3+ ion concentration have been studied and reported in the present work.

Contribution of S4 segments and S4-S5 linkers to the low-voltage activation properties of T-type CaV3.3 channels.

Directory of Open Access Journals (Sweden)

Ana Laura Sanchez-Sandoval

Full Text Available Voltage-gated calcium channels contain four highly conserved transmembrane helices known as S4 segments that exhibit a positively charged residue every third position, and play the role of voltage sensing. Nonetheless, the activation range between high-voltage (HVA and low-voltage (LVA activated calcium channels is around 30-40 mV apart, despite the high level of amino acid similarity within their S4 segments. To investigate the contribution of S4 voltage sensors for the low-voltage activation characteristics of CaV3.3 channels we constructed chimeras by swapping S4 segments between this LVA channel and the HVA CaV1.2 channel. The substitution of S4 segment of Domain II in CaV3.3 by that of CaV1.2 (chimera IIS4C induced a ~35 mV shift in the voltage-dependence of activation towards positive potentials, showing an I-V curve that almost overlaps with that of CaV1.2 channel. This HVA behavior induced by IIS4C chimera was accompanied by a 2-fold decrease in the voltage-dependence of channel gating. The IVS4 segment had also a strong effect in the voltage sensing of activation, while substitution of segments IS4 and IIIS4 moved the activation curve of CaV3.3 to more negative potentials. Swapping of IIS4 voltage sensor influenced additional properties of this channel such as steady-state inactivation, current decay, and deactivation. Notably, Domain I voltage sensor played a major role in preventing CaV3.3 channels to inactivate from closed states at extreme hyperpolarized potentials. Finally, site-directed mutagenesis in the CaV3.3 channel revealed a partial contribution of the S4-S5 linker of Domain II to LVA behavior, with synergic effects observed in double and triple mutations. These findings indicate that IIS4 and, to a lesser degree IVS4, voltage sensors are crucial in determining the LVA properties of CaV3.3 channels, although the accomplishment of this function involves the participation of other structural elements like S4-S5 linkers.

Contribution of S4 segments and S4-S5 linkers to the low-voltage activation properties of T-type CaV3.3 channels

Science.gov (United States)

Sanchez-Sandoval, Ana Laura; Herrera Carrillo, Zazil; Díaz Velásquez, Clara Estela; Delgadillo, Dulce María; Rivera, Heriberto Manuel

2018-01-01

Voltage-gated calcium channels contain four highly conserved transmembrane helices known as S4 segments that exhibit a positively charged residue every third position, and play the role of voltage sensing. Nonetheless, the activation range between high-voltage (HVA) and low-voltage (LVA) activated calcium channels is around 30–40 mV apart, despite the high level of amino acid similarity within their S4 segments. To investigate the contribution of S4 voltage sensors for the low-voltage activation characteristics of CaV3.3 channels we constructed chimeras by swapping S4 segments between this LVA channel and the HVA CaV1.2 channel. The substitution of S4 segment of Domain II in CaV3.3 by that of CaV1.2 (chimera IIS4C) induced a ~35 mV shift in the voltage-dependence of activation towards positive potentials, showing an I-V curve that almost overlaps with that of CaV1.2 channel. This HVA behavior induced by IIS4C chimera was accompanied by a 2-fold decrease in the voltage-dependence of channel gating. The IVS4 segment had also a strong effect in the voltage sensing of activation, while substitution of segments IS4 and IIIS4 moved the activation curve of CaV3.3 to more negative potentials. Swapping of IIS4 voltage sensor influenced additional properties of this channel such as steady-state inactivation, current decay, and deactivation. Notably, Domain I voltage sensor played a major role in preventing CaV3.3 channels to inactivate from closed states at extreme hyperpolarized potentials. Finally, site-directed mutagenesis in the CaV3.3 channel revealed a partial contribution of the S4-S5 linker of Domain II to LVA behavior, with synergic effects observed in double and triple mutations. These findings indicate that IIS4 and, to a lesser degree IVS4, voltage sensors are crucial in determining the LVA properties of CaV3.3 channels, although the accomplishment of this function involves the participation of other structural elements like S4-S5 linkers. PMID:29474447

Contribution of S4 segments and S4-S5 linkers to the low-voltage activation properties of T-type CaV3.3 channels.

Science.gov (United States)

Sanchez-Sandoval, Ana Laura; Herrera Carrillo, Zazil; Díaz Velásquez, Clara Estela; Delgadillo, Dulce María; Rivera, Heriberto Manuel; Gomora, Juan Carlos

2018-01-01

Voltage-gated calcium channels contain four highly conserved transmembrane helices known as S4 segments that exhibit a positively charged residue every third position, and play the role of voltage sensing. Nonetheless, the activation range between high-voltage (HVA) and low-voltage (LVA) activated calcium channels is around 30-40 mV apart, despite the high level of amino acid similarity within their S4 segments. To investigate the contribution of S4 voltage sensors for the low-voltage activation characteristics of CaV3.3 channels we constructed chimeras by swapping S4 segments between this LVA channel and the HVA CaV1.2 channel. The substitution of S4 segment of Domain II in CaV3.3 by that of CaV1.2 (chimera IIS4C) induced a ~35 mV shift in the voltage-dependence of activation towards positive potentials, showing an I-V curve that almost overlaps with that of CaV1.2 channel. This HVA behavior induced by IIS4C chimera was accompanied by a 2-fold decrease in the voltage-dependence of channel gating. The IVS4 segment had also a strong effect in the voltage sensing of activation, while substitution of segments IS4 and IIIS4 moved the activation curve of CaV3.3 to more negative potentials. Swapping of IIS4 voltage sensor influenced additional properties of this channel such as steady-state inactivation, current decay, and deactivation. Notably, Domain I voltage sensor played a major role in preventing CaV3.3 channels to inactivate from closed states at extreme hyperpolarized potentials. Finally, site-directed mutagenesis in the CaV3.3 channel revealed a partial contribution of the S4-S5 linker of Domain II to LVA behavior, with synergic effects observed in double and triple mutations. These findings indicate that IIS4 and, to a lesser degree IVS4, voltage sensors are crucial in determining the LVA properties of CaV3.3 channels, although the accomplishment of this function involves the participation of other structural elements like S4-S5 linkers.

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.)

Behaviour of Er/sup 3 +/ ion in tetragonal crystalline field

Energy Technology Data Exchange (ETDEWEB)

Kumar, V; Dass, N; Chandra, K [Roorkee Univ. (India). Dept. of Physics

1976-12-01

Crystal field parameters for ErGaG and Er/sup 3 +/ YAlG are used to compute the temperature dependence of Schottky specific heat, paramagnetic susceptibility, magnetic anisotropy, sup(..mu..)eff and quadrupole splitting in the range 10-400 K. The hyperfine interaction parameters A and B for /sup 16/ /sup 166/Er and /sup 167/Er in both the systems are also obtained and in turn used to estimate the nuclear specific heat contribution. The studied parameters compare well with the available experimental results.

Synthesis, Structural Characterization and Up-Conversion Luminescence Properties of NaYF4:Er3+,Yb3+@MOFs Nanocomposites

Science.gov (United States)

Giang, Lam Thi Kieu; Marciniak, Lukasz; Huy, Tran Quang; Vu, Nguyen; Le, Ngo Thi Hong; Binh, Nguyen Thanh; Lam, Tran Dai; Minh, Le Quoc

2017-10-01

This paper describes a facile synthesis of NaYF4:Er3+,Yb3+ nanoparticles embraced in metal-organic frameworks (MOFs), known as NaYF4:Er3+, Yb3+@MOFs core/shell nanostructures, by using iron(III) carboxylate (MIL-100) and zeolitic imidazolate frameworks (ZIF-8). Morphological, structural and optical characterization of these nanostructures were investigated by field emission-scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, and up-conversion luminescence measurements. Results showed that spherical-shaped NaYF4:Er3+,Yb3+@MIL-100 nanocomposites with diameters of 150-250 nm, and rod-shaped NaYF4:Er3+,Yb3+@ZIF-8 nanocomposites with lengths of 300-550 nm, were successfully synthesized. Under a 980-nm laser excitation at room temperature, the NaYF4:Er3+,Yb3+@MOFs nanocomposites exhibited strong up-conversion luminescence with two emission bands in the green part of spectrum at 520 nm and 540 nm corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ ions, respectively, and a red emission band at 655 nm corresponding to the 4F9/2 → 4I15/2 transition of Er3+ ions. The above properties of NaYF4:Er3+,Yb3+@MOFs make them promising candidates for applications in biotechnology.

Frequency upconversion fluorescence studies of Er{sup 3+}/Yb{sup 3+}-codoped KNbO{sub 3} phosphors

Energy Technology Data Exchange (ETDEWEB)

Balakrishnaiah, R. [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Kim, Dong Woo [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Yi, Soung Soo, E-mail: ssyi@silla.ac.k [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Kim, Kwang Duk; Kim, Sung Hoon [Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Jang, Kiwan; Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Jeong, Jung Hyun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of)

2009-05-29

Different concentrations of Er{sup 3+} and Yb{sup 3+} ions-doped potassium niobate (K{sub 0.9}NbO{sub 3}:Yb{sub (x)}Er{sub (0.1-x)} for x = 0, 0.01, 0.05, 0.09 and 0.1) polycrystalline powder phosphors were prepared by the conventional solid state reaction method and were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Energy transfer and upconversion fluorescence properties of the Yb{sup 3+} and Er{sup 3+}-codoped phosphors have been discussed. The XRD data has shown mono-phase for pure KNbO{sub 3} while the doped samples represented additional phase formation. The SEM micrographs represented the rectangular crystal growth habit for the KNbO{sub 3} phosphors when doped with 0.1 mol of Er{sup 3+} ions. An intense green emission at 557 nm along with a red emission at 674 nm was observed when the doped samples were excited with 975 nm IR radiation. The upconversion mechanism has been discussed based on the excited state absorption and energy transfer mechanisms.

Optical energy gaps and photoluminescence peaks of BaGa{sub 2}S{sub 4}:Er{sup 3+} and BaGa{sub 2}Se{sub 4}:Er{sup 3+} single crystals

Energy Technology Data Exchange (ETDEWEB)

Choe, Sung-Hyu [Chosun University, Kwangju (Korea, Republic of); Jin, Moon-Seog [Dongshin University, Naju (Korea, Republic of); Kim, Wha-Tek [Chonnam National University, Kwangju (Korea, Republic of)

2005-12-15

BaGa{sub 2}S{sub 4}:Er{sup 3+} and BaGa{sub 2}Se{sub 4}:Er{sup 3+} single crystals were grown by using the chemical transport reaction method. The optical energy gaps of the BaGa{sub 2}S{sub 4}:Er{sup 3+} and the BaGa{sub 2}Se{sub 4}:Er{sup 3+} single crystals were found to be 4.045 eV and 3.073 eV, respectively, at 11 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Sharp emission peaks were observed in the photoluminescence spectra of the single crystals and assigned to radiation recombination between split Stark levels of the Er{sup 3+} ion.

Synthesis of "trans"-4,5-Bis-dibenzylaminocyclopent-2-Enone from Furfural Catalyzed by ErCl[subscript 3]·6H[subscript 2]O

Science.gov (United States)

Estevão, Mónica S.; Martins, Ricardo J. V.; Alfonso, Carlos A. M.

2017-01-01

An experiment exploring the chemistry of the carbonyl group for the one-step synthesis of "trans"-4,5- dibenzylaminocyclopent-2-enone is described. The reaction of furfural and dibenzylamine in the environmentally friendly solvent ethanol and catalyzed by the Lewis acid ErCl[subscript 3]·6H[subscript 2]O afforded the product in high…

Influences of Er3+ content on structure and upconversion emission of oxyfluoride glass ceramics containing CaF2 nanocrystals

International Nuclear Information System (INIS)

Chen Daqin; Wang Yuansheng; Yu Yunlong; Ma En; Bao Feng; Hu Zhongjian; Cheng Yao

2006-01-01

Transparent 45SiO 2 -25Al 2 O 3 -5CaO-10NaF-15CaF 2 glass ceramics doped with different content of erbium ion (Er 3+ ) were prepared. X-ray diffraction (XRD) and transmission electron microscope (TEM) analyses evidenced the spherical CaF 2 nanocrystals homogeneously embedded among the glassy matrix. With increasing of Er 3+ content, the size of CaF 2 nanocrystals decreased while the number density increased. The crystallization kinetics studies revealed that CaF 2 crystallization was a diffusion-controlled growth process from small dimensions with decreasing nucleation rate. Er 3+ could act as nucleating agent to lower down crystallization temperature, while some of them may stay at the crystal surfaces to retard the growth of crystal. Intense red and weak green upconversion emissions were recorded for glass ceramics and their intensities increased with the increasing of Er 3+ content under 980 nm excitation. However, the concentration quenching effect appeared when Er 3+ doping reached 2 mol%. These results could be attributed to the change of ligand field of Er 3+ ions due to the incorporation of Er 3+ ions into precipitated fluoride nanocrystals

Yb3+,Er3+,Eu3+-codoped YVO4 material for bioimaging with dual mode excitation

International Nuclear Information System (INIS)

Thao, Chu Thi Bich; Huy, Bui The; Sharipov, Mirkomil; Kim, Jin-Ik.; Dao, Van-Duong; Moon, Ja-Young; Lee, Yong-Ill

2017-01-01

We propose an efficient bioimaging strategy using Yb 3+ ,Er 3+ ,Eu 3+ -triplet doped YVO 4 nanoparticles which were synthesized with polymer as a template. The obtained particles possess nanoscale, uniform, and flexible excitation. The effect of Eu 3+ ions on the luminescence properties of YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ was investigated. The upconversion mechanism of the prepared material was also discussed. The structure and optical properties of the prepared material were characterized by using X-ray diffraction (XRD), Fourier-transform IR spectroscopy (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) upconversion and photoluminescence spectra. The Commission International de I′Eclairage (CIE) chromaticity coordinates was investigated to confirm the performance of color luminescent emission. The prepared YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ nanoparticles could be easily dispersed in water by surface modification with cysteine (Cys) and glutathione (GSH). The aqueous dispersion of the modified YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ exhibits bright upconversion and downconversion luminescence and has been applied for bioimaging of HeLa cells. Our developed material with dual excitation offers a promising advance in bioimaging. - Highlights: • Prepared particles possess nanoscale size, uniform, and larger scale. • The material exhibits strong emission under dual mode excitations. • The surface material has been applied for bioimaging of HeLa cell. • Low cytotoxicity, no auto-fluorescence

The effect of erbium on the adsorption and photodegradation of orange I in aqueous Er3+-TiO2 suspension

International Nuclear Information System (INIS)

Liang Chunhua; Hou Meifang; Zhou Shungui; Li Fangbai; Liu Chengshuai; Liu Tongxu; Gao Yuanxue; Wang Xugang; Lue Jialong

2006-01-01

Pure TiO 2 and erbium ion-doped TiO 2 (Er 3+ -TiO 2 ) catalysts prepared by the sol-gel method were characterized by means of XRD and diffusive reflectance spectra (DRS). The XRD results showed that erbium ion doping could enhance the thermal stability of TiO 2 and inhibit the increase of the crystallite size, and the DRS results showed that the optical absorption edge slightly shifted to red direction owing to erbium ion doping and the Er 3+ -TiO 2 catalysts had three typical absorption peaks located at 490, 523 and 654 nm owing to the transition of 4f electron from 4 I 15/2 to 4 F 7/2 , 2 H 11/2 and 4 F 9/2 . With a purpose of azo dyes degradation, orange I was used as a model chemical. And the adsorption isotherm, degradation and mineralization of orange I were investigated in aqueous suspension of pure TiO 2 or Er 3+ -TiO 2 catalysts. The results showed that Er 3+ -TiO 2 catalysts had higher adsorption equilibrium constants and better adsorption capacity than pure TiO 2 . The adsorption equilibrium constants (K a ) of Er 3+ -TiO 2 catalysts were about twice of that of pure TiO 2 . The maximum adsorption capacity (Q max ) of 2.0% Er 3+ -TiO 2 catalyst was 13.08 x 10 -5 mol/g, which was much higher than that of pure TiO 2 with 9.03 x 10 -5 mol/g. Among Er 3+ -TiO 2 catalysts, 2.0% Er 3+ -TiO 2 catalyst achieved the highest Q max and K a values. The kinetics of the orange I degradation using different Er 3+ -TiO 2 catalysts were also studied. The results demonstrated that the degradation and mineralization of orange I under both UV radiation and visible light were more efficient with Er 3+ -TiO 2 catalyst than with pure TiO 2 , and an optimal dosage of erbium ion at 1.5% achieved the highest degradation rate. The higher photoactivity under visible light might be attributable to the transitions of 4f electrons of Er 3+ and red shifts of the optical absorption edge of TiO 2 by erbium ion doping

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

Science.gov (United States)

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

2005-10-03

The reaction of Ln(NO3)3(aq) with K3[Fe(CN)6] or K3[Co(CN)6] and 2,2'-bipyridine in water/ethanol led to 13 one-dimensional complexes: trans-[M(CN)4(mu-CN)2Ln(H2O)4(bpy)]n.4nH2O.1.5nbpy (Ln = Eu3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Lu3+; M = Fe3+, Co3+). The structures for [EuFe]n (1), [TbFe]n (2), [DyFe]n (3), [HoFe]n (4), [ErFe]n (5), [TmFe]n (6), [LuFe]n (7), [EuCo]n (8), [TbCo]n (9), [DyCo]n (10), [HoCo]n (11), [ErCo]n (12), and [TmCo]n (13) have been solved: they crystallize in the triclinic space group P and are isomorphous. They exhibit a supramolecular architecture created by the interplay of coordinative, hydrogen bonding, and pi-pi interactions. A stereochemical study of the eight-vertex polyhedra of the lanthanide ions, based on continuous shape measures, is presented. The Ln3+-Fe3+ interaction is antiferromagnetic in [DyFe]n and [TbFe]n. For [EuFe]n, [HoFe]n, [ErFe]n, and [TmFe]n, there is no sign of any significant interaction. The magnetic behavior of [DyFe]n suggests the onset of weak long-range ferromagnetic ordering at 2.5 K.

Optical temperature sensing by upconversion luminescence of Er doped Bi5TiNbWO15ferroelectric materials

Directory of Open Access Journals (Sweden)

Hua Zou

2014-12-01

Full Text Available The Er3+ doped Bi5TiNbWO15 ceramics have been synthesized using conventional solid-state reaction techniques. The crystal structure, ferroelectric properties, UC emission properties and especially the temperature sensing behaviors were systematically studied. With increasing Er3+ content, the investigation of XRD pattern, the ferroelectric loop and the UC emission indicated that the Er3+ ions dopants preferentially substituted the A sites of Bi3TiNbO9 and then Bi2WO6. Based on fluorescence intensity ratio (FIR technique, the observed results implied the ceramics were promising candidates for temperature sensors in the temperature range of 175 K −550 K. More importantly, this study provided a contrast of temperature sensitivity between emission from the same part (Bi3TiNbO9 in bismuth layered-structure and emission from the different part (Bi3TiNbO9 and Bi2WO6 in bismuth layered-structure for the first time.

High multi-photon visible upconversion emissions of Er{sup 3+} singly doped BiOCl microcrystals: A photon avalanche of Er{sup 3+} induced by 980 nm excitation

Energy Technology Data Exchange (ETDEWEB)

Li, Yongjin; Song, Zhiguo, E-mail: songzg@kmust.edu.cn; Li, Chen; Wan, Ronghua; Qiu, Jianbei; Yang, Zhengwen; Yin, Zhaoyi; Yang, Yong; Zhou, Dacheng; Wang, Qi [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

2013-12-02

Under 980 nm excitation, high multi-photon upconversion (UC) emission from the {sup 2}H{sub 11/2}/{sup 4}S{sub 3/2} (green) and {sup 4}F{sub 9/2} (red) levels of Er{sup 3+} ions were observed from Er{sup 3+} singly doped BiOCl microcrystals. These high-energy excited states were populated by a three to ten photon UC process conditionally, which depended on the pump power density and the Er{sup 3+} ion doping concentration, characterizing as a hetero-looping enhanced energy transfer avalanche UC process. UC emission lifetime and Raman analysis suggest that the unusual UC phenomena are initiated by the new and intense phonon vibration modes of BiOCl lattices due to Er{sup 3+} ions doping.

Hydrothermal synthesis and upconversion luminescent properties of YVO4:Yb3+,Er3+ nanoparticles

International Nuclear Information System (INIS)

Liang, Yanjie; Chui, Pengfei; Sun, Xiaoning; Zhao, Yan; Cheng, Fuming; Sun, Kangning

2013-01-01

Graphical abstract: YVO 4 :Yb 3+ ,Er 3+ nanoparticles have been successfully prepared via a facile hydrothermal technique in the presence of citric acid as a complexing agent followed by a subsequent heat treatment process. The PL intensity of the sample increases with the increase of annealing temperature and excitation power. Under the excitation of a 980 nm diode laser, the samples show bright green luminescence. Highlights: ► YVO 4 :Yb 3+ ,Er 3+ nanoparticles were prepared by a hydrothermal approach. ► Bright green luminescence is observed under the excitation of a 980 nm laser diode. ► The PL intensity increases with the increase of annealing temperature. ► Energy transfer properties between Yb 3+ ion and Er 3+ ion were analyzed. -- Abstract: In this paper, YVO 4 :Yb 3+ ,Er 3+ nanoparticles have been successfully prepared via a facile hydrothermal technique in the presence of citric acid as a complexing agent followed by a subsequent heat treatment process. The nanostructures, morphologies and upconversion luminescent properties of the as-prepared YVO 4 :Yb 3+ ,Er 3+ upconverting nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescent (PL) spectra. XRD results indicate that all the diffraction peaks of samples can be well indexed to the tetragonal phase of YVO 4 . TEM images demonstrate that the samples synthesized hydrothermally consist of granular-like nanoparticles ranging in size from about 30 to 50 nm. After being calcined at 500–800 °C for 2 h, the grain sizes of nanoparticles increase slightly. Additionally, the as-prepared nanoparticles show bright green luminescence corresponding to the 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions of Er 3+ ions under the excitation of a 980 nm diode laser, which might find potential applications in fields such as phosphor powders, infrared detection and display devices

Infrared to visible upconversion luminescence in Er3+/Yb3+ co-doped CeO2 inverse opal

International Nuclear Information System (INIS)

Yang, Zhengwen; Wu, Hangjun; Liao, Jiayan; Li, Wucai; Song, Zhiguo; Yang, Yong; Zhou, Dacheng; Wang, Rongfei; Qiu, Jianbei

2013-01-01

Highlights: • UC emission of Er 3+ was modified by introducing the structure of inverse opal. • Color tuning of CeO 2 :Yb, Er inverse opal was realized by inhibition of UC emission. • Two-photon excitation processes were observed in CeO 2 :Yb, Er inverse opal. -- Abstract: Infrared to visible upconversion luminescence has been investigated in Er 3+ /Yb 3+ co-doped CeO 2 inverse opal. Under the excitation of 980 nm diode lasers, visible emissions centered at 525, 547, 561, 660 and 680 nm are observed, which are assigned to the Er 3+ transitions of 2 H 11/2 → 4 I 15/2 (525 nm), 4 S 3/2 → 4 I 15/2 (547, 561 nm), 4 F 9/2 → 4 I 15/2 (660 and 680 nm), respectively. The effect of photonic band gap on the upconversion luminescence intensity was also obtained. Additionally, the upconversion luminescence mechanism was studied. The dependence of Er 3+ upconversion emission intensity on pump power reveals that it is a two-photon excitation process

Isothermal section of the Er-Cu-Ga ternary system at 973 K

Energy Technology Data Exchange (ETDEWEB)

Belgacem, B. [Unite de Recherche de Chimie des Materiaux et de l' Environnement (UR11ES25), ISSBAT, Universite de Tunis ElManar, 9 Avenue Dr. Zoheir Safi, 1006 Tunis (Tunisia); Pasturel, M., E-mail: mathieu.pasturel@univ-rennes1.fr [Institut des Sciences Chimiques de Rennes, Chimie du Solide et Materiaux, UMR CNRS 6226, Universite de Rennes 1, Campus de Beaulieu, 35042 Rennes (France); Tougait, O. [Institut des Sciences Chimiques de Rennes, Chimie du Solide et Materiaux, UMR CNRS 6226, Universite de Rennes 1, Campus de Beaulieu, 35042 Rennes (France); Nouri, S. [Unite de Recherche de Chimie des Materiaux et de l' Environnement (UR11ES25), ISSBAT, Universite de Tunis ElManar, 9 Avenue Dr. Zoheir Safi, 1006 Tunis (Tunisia); Bekkachi, H. El; Peron, I. [Institut des Sciences Chimiques de Rennes, Chimie du Solide et Materiaux, UMR CNRS 6226, Universite de Rennes 1, Campus de Beaulieu, 35042 Rennes (France); Hassen, R. Ben [Unite de Recherche de Chimie des Materiaux et de l' Environnement (UR11ES25), ISSBAT, Universite de Tunis ElManar, 9 Avenue Dr. Zoheir Safi, 1006 Tunis (Tunisia); Noeel, H. [Institut des Sciences Chimiques de Rennes, Chimie du Solide et Materiaux, UMR CNRS 6226, Universite de Rennes 1, Campus de Beaulieu, 35042 Rennes (France)

2012-08-05

Highlights: Black-Right-Pointing-Pointer The isothermal section at 973 K of the Er-Cu-Ga ternary phase diagram has been established for the first time. Black-Right-Pointing-Pointer Eight extensions of binary compounds in the ternary domain have been identified, as well as six ternary intermediate solid solutions characterized by an important Cu/Ga mutual substitution. Black-Right-Pointing-Pointer Magnetic properties of Er{sub 3}(Cu,Ga){sub 11} are reported for the first time and confirms the paramagnetic Curie-Weiss behavior of all the six intermediate intermetallics. - Abstract: Phase relations in the Er-Cu-Ga ternary system have been established at 973 K by means of powder X-ray diffraction complemented by energy dispersive spectroscopy coupled to scanning electron microscopy. The isothermal section of the phase diagram comprises eight extensions of binaries into the ternary system, ErCu{sub 1-x}Ga{sub x} (x {<=} 0.5), ErCu{sub 2-x}Ga{sub x} (x {<=} 1.1), ErCu{sub 5-x}Ga{sub x} (x {<=} 0.5), Er{sub 5}Cu{sub x}Ga{sub 3-x} (x {<=} 0.60), Er{sub 3}Cu{sub x}Ga{sub 2-x} (x {<=} 0.24), ErCu{sub x}Ga{sub 1-x} (x {<=} 0.10), ErCu{sub x}Ga{sub 2-x} (x {<=} 0.30) and ErCu{sub x}Ga{sub 3-x} (x {<=} 0.35), as well as six ternary intermediate phases, ErCu{sub x}Ga{sub 2-x} (0.4 {<=} x {<=} 0.7), Er{sub 14}Cu{sub 51-x}Ga{sub x} (5.5 {<=} x {<=} 11.0), ErCu{sub 5-x}Ga{sub x} (0.8 {<=} x {<=} 2.3), Er{sub 2}Cu{sub 17-x}Ga{sub x} (4.9 {<=} x {<=} 8.0), ErCu{sub 12-x}Ga{sub x} (5.7 {<=} x {<=} 6.7) and Er{sub 3}Cu{sub x}Ga{sub 11-x} (1.5 {<=} x {<=} 4.4), all deriving from binary structure-types.

Enhanced electrical properties, color-tunable up-conversion luminescence, and temperature sensing behaviour in Er-doped Bi3Ti1.5W0.5O9 multifunctional ferroelectric ceramics

Science.gov (United States)

Zhang, Ying; Li, Jun; Chai, Xiaona; Wang, Xusheng; Li, Yongxiang; Yao, Xi

2017-03-01

Er-doped Bi3Ti1.5W0.5O9 (BTW-x) ferroelectric ceramics were prepared by a conventional solid-state reaction synthesis method, and their structure, electrical properties, up-conversion (UC) luminescence, and temperature sensing behaviour were investigated. A high piezoelectric coefficient d33 (9.6 pC/N), a large remnant polarization Pr (12.75 μC/cm2), a high Curie temperature Tc (730.2 °C), and the optimal luminescent intensity are obtained for the samples at x = 0.05. By changing the Er doped concentration, the BTW-x ceramics are capable of generating various UC spectra and the color could be tunable from green to yellow. According to the fluorescence intensity ratio of green emissions at 532.6 nm and 549.2 nm in the temperature range from 83 K to 423 K, optical temperature sensing properties are investigated and the maximum sensing sensitivity is found to be 0.00314 K-1 at 423 K. The results conclude that BTW-x would be a candidate in high temperature sensor, fluorescence thermometry, and opto-electronic integration applications.

Magnetic characterization of microcrystalline Na3Ln0.99–xEr0.01Crx(PO42 orthophosphates synthesized by Pechini method (Ln = La, Gd

Directory of Open Access Journals (Sweden)

Kaczmarek S.M.

2018-03-01

Full Text Available Na3Ln(PO42 orthophosphates (Ln = La, Gd doped with Er3+ and co-doped with Cr3+ ions were synthesized by Pechini method and characterized by electron paramagnetic resonance (EPR and magnetic susceptibility measurements. Low temperature EPR spectra were detected and analyzed in terms of temperature dependence and the structure of the obtained materials. They show that erbium and chromium ions substitute Ln3+ and also Na+ ions or Na+ channels forming complex EPR spectra. Both kinds of ions reveal ferromagnetic type of interaction which shows some anomaly at the temperature between 10 K and 15 K. Magnetic susceptibility reveals a weak antiferromagnetic kind of interaction dominating in the whole temperature range, from 3.5 to 300 K.

Single crystalline Er{sub 2}O{sub 3}:sapphire films as potentially high-gain amplifiers at telecommunication wavelength

Energy Technology Data Exchange (ETDEWEB)

Kuznetsov, A. S.; Sadofev, S.; Schäfer, P.; Kalusniak, S.; Henneberger, F., E-mail: fh@physik.hu-berlin.de [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany)

2014-11-10

Single crystalline thin films of Er{sub 2}O{sub 3}, demonstrating efficient 1.5 μm luminescence of Er{sup 3+} at room temperature were grown on Al{sub 2}O{sub 3} substrate by molecular beam epitaxy. The absorption coefficient at 1.536 μm was found to reach 270 cm{sup −1} translating in a maximal possible gain of 1390 dBcm{sup −1}. In conjunction with the 10% higher refractive index as compared to Al{sub 2}O{sub 3}, this opens the possibility to use Er{sub 2}O{sub 3}:sapphire films as short-length waveguide amplifiers in telecommunication.

Investigations on luminescence behavior of Er3+/Yb3+ co-doped boro-tellurite glasses

Science.gov (United States)

Maheshvaran, K.; Arunkumar, S.; Venkata Krishnaiah, K.; Marimuthu, K.

2015-01-01

Er3+/Yb3+ co-doped boro-tellurite glasses with the chemical composition 30TeO2+(24 - x)B2O3 + 15SrO + 10BaO + 10Li2O + 10LiF + 1Er2O3 + xYb2O3 (where x = 0, 0.1, 0.5, 1 and 2 in wt%) have been prepared and their luminescence behavior were studied and reported. Absorption spectral measurements have been used to derive the Judd-Ofelt (JO) intensity parameters from the experimental and calculated oscillator strength values following the JO theory. The various lasing parameters such as stimulated emission cross-section (σEp), experimental and calculated branching ratios (βR) and radiative lifetime (τcal) for the 2H9/2 → 4I15/2, 4S3/2 → 4I15/2 and 4I13/2 → 4I15/2 emission transitions were determined using the JO intensity parameters. The absorption and emission cross-section values for the 4I13/2 → 4I15/2 emission band have been calculated using McCumbar theory and the Gain cross-section for the 4I13/2 → 4I15/2 emission transition also obtained. The upconversion emission mechanism have been studied through various energy transfer processes and the intensity of the upconversion emission transitions are found to increase with the increase in Yb3+ ion concentration. The luminescence decay curves corresponding to the 4I13/2 → 4I15/2 transition of the Er3+/Yb3+ co-doped boro-tellurite glasses under 980 nm excitation wavelength have also been studied and reported in the present work.

Neutron diffraction study of antiferromagnetic ErNi3Ga9 in magnetic fields

Science.gov (United States)

Ninomiya, Hiroki; Sato, Takaaki; Matsumoto, Yuji; Moyoshi, Taketo; Nakao, Akiko; Ohishi, Kazuki; Kousaka, Yusuke; Akimitsu, Jun; Inoue, Katsuya; Ohara, Shigeo

2018-05-01

We report specific heat, magnetization, magnetoresistance, and neutron diffraction measurements of single crystals of ErNi3Ga9. This compound crystalizes in a chiral structure with space group R 32 . The erbium ions form a two-dimensional honeycomb structure. ErNi3Ga9 displays antiferromagnetic order below 6.4 K. We determined that the magnetic structure is slightly amplitude-modulated as well as antiferromagnetic with q = (0 , 0 , 0.5) . The magnetic properties are described by an Ising-like model in which the magnetic moment is always along the c-axis owing to the large uniaxial anisotropy caused by the crystalline electric field effect in the low temperature region. When the magnetic field is applied along the c-axis, a metamagnetic transition is observed around 12 kOe at 2 K. ErNi3Ga9 possesses crystal chirality, but the antisymmetric magnetic interaction, the so-called Dzyaloshinskii-Moriya (DM) interaction, does not contribute to the magnetic structure, because the magnetic moments are parallel to the DM-vector.

Photoluminescence of rare-earth ion (Eu3+, Tm3+, and Er3+)-doped and co-doped ZnNb2O6 for solar cells

Science.gov (United States)

Gao, Sen-Pei; Qian, Yan-Nan; Wang, Biao

2015-08-01

Visible converted emissions produced at an excitation of 286 nm in ZnNb2O6 ceramics doped with rare-earth ions (RE = Eu3+, Tm3+, Er3+ or a combination of these ions) were investigated with the aim of increasing the photovoltaic efficiency of solar cells. The structure of RE:ZnNb2O6 ceramics was confirmed by x-ray diffraction patterns. The undoped ZnNb2O6 could emit a blue emission under 286-nm excitation, which is attributed to the self-trapped excitons’ recombination of the efficient luminescence centers of edge-shared NbO6 groups. Upon 286-nm excitation, Eu:ZnNb2O6, Tm:ZnNb2O6, and Er:ZnNb2O6 ceramics showed blue, green, and red emissions, which correspond to the transitions of 5D0 → 7FJ (J = 1-4) (Eu3+), 1G4 → 3H6 (Tm3+), and 2H11/2/4S3/2 → 4I15/2 (Er3+), respectively. The calculated CIE chromaticity coordinates of Eu:ZnNb2O6, Tm:ZnNb2O6, and Er:ZnNb2O6 are (0.50, 0.31), (0.14, 0.19), and (0.29, 0.56), respectively. RE ion-co-doped ZnNb2O6 showed a combination of characteristic emissions. The chromaticity coordinates of Eu/Tm:ZnNb2O6, Eu/Er:ZnNb2O6, and Tm/Er:ZnNb2O6 were calculated to be (0.29, 0.24), (0.45, 0.37), and (0.17, 0.25). Project supported by the National Natural Science Foundation of China (Grant Nos. 10572155 and 10732100) and the Research Fund for the Doctoral Program of Ministry of Education, China (Grant No. 20130171130003).

Superstructure formation in PrNi_2Al_3 and ErPd_2Al_3

International Nuclear Information System (INIS)

Eustermann, Fabian; Hoffmann, Rolf-Dieter; Janka, Oliver; Oldenburg Univ.

2017-01-01

The intermetallic phase ErPd_2Al_3 was obtained by arc-melting of the elements and subsequent annealing for crystal growth. The sample was studied by X-ray diffraction on powders and single crystals. The structure of ErPd_2Al_3 was refined from X-ray diffraction data and revealed a superstructure of PrNi_2Al_3 - a CaCu_5 derivative (P6/m, a=1414.3(1), c=418.87(3) pm wR=0.0820, 1060 F"2 values, 48 variables). The same superstructure was subsequently found for PrNi_2Al_3 (P6/m, a=1407.87(4), c=406.19(2) pm, wR=0.0499, 904 F"2 values, 47 variables). In the crystal structure, the aluminium and transition metal atoms form a polyanionic network according to [T_2Al_3]"δ"-, while rare earth atoms fill cavities within the networks. They are coordinated by six transition metal and twelve aluminum atoms. In contrast to the PrNi_2Al_3 type structure reported so far, two crystallographic independent rare-earth sites are found of which one (1b) is shifted by 1/2 z, causing a distortion in the structure along with a recoloring of the T and Al atoms in the network.

Effects of Er3+ concentration on UV/blue upconverted luminescence and a three-photon process in the cubic nanocrystalline Y2O3:Er3+

International Nuclear Information System (INIS)

Wang Xin; Shan Guiye; Chao Kefu; Zhang Youlin; Liu Ruilin; Feng Liyun; Zeng Qinghui; Sun Yajuan; Liu Yichun; Kong Xianggui

2006-01-01

Ultraviolet (UV)/blue upconverted luminescent properties of the cubic Y 2 O 3 :Er 3+ nanocrystals as a function of the erbium concentration were investigated upon 488 nm Ar + laser excitation. The remarkable decrease of upconverted emission intensity and the quenching of the 2 P 3/2 → 4 I 11/2 / 4 I 13/2 transitions were observed in the Y 2 O 3 nanocrystals with high erbium concentration. The emission spectra and the exciting power dependence of upconverted luminescent intensities reveal that the possible upconversion mechanisms are excited-state absorption (ESA) and energy transfer (ET). Moreover, a UV/violet upconverted emission spectrum of nanocrystalline Y 2 O 3 :Er 3+ upon 980 nm light excitation was also observed and a three-photon process made a contribution to this upconverted emission

Efficient 1.54-μm emission through Eu2+ sensitization of Er3+ in thin films of Eu2+/Er3+ codoped barium strontium silicate under broad ultraviolet light excitation

International Nuclear Information System (INIS)

Li, Leliang; Zheng, Jun; Zuo, Yuhua; Cheng, Buwen; Wang, Qiming

2015-01-01

Thin films of Eu 2+ /Er 3+ codoped barium strontium silicate were deposited on a thermal oxide Si substrate by magnetron sputtering. Optical properties suggest that after a rapid annealing process, these films can lead to efficient Er 3+ emission at 1.54 μm with a lifetime of about 7.9 ms. Intense 1.54-μm light emission was achieved under broad ultraviolet light excitation through efficient energy transfer from Eu 2+ to Er 3+ . These results indicate that the Eu 2+ /Er 3+ thin films have potential applications as low cost and compact erbium doped waveguide amplifiers pumped by LEDs. - Highlights: • The Er 0.07 Eu 0.14 Sr 1.14 Ba 0.79 SiO 4 films are fabricated by magnetron sputtering. • Efficient energy transfer from Eu 2+ to Er 3+ ions by the dipole–dipole interaction. • Intense 1.54 μm emission is achieved under broad excitation spectrum. • The films have potential applications as low cost and compact EDWAs

AFM observation of OMVPE-grown ErP on InP substrates using a new organometal tris(ethylcyclopentadienyl)erbium (Er(EtCp)3)

International Nuclear Information System (INIS)

Akane, T.; Jinno, S.; Yang, Y.; Kuno, T.; Hirata, T.; Isogai, Y.; Watanabe, N.; Fujiwara, Y.; Nakamura, A.; Takeda, Y.

2003-01-01

ErP has been grown on InP(0 0 1) substrates by organometallic vapor phase epitaxy (OMVPE) using a new liquid organic Er source: tris(ethylcyclopentadienyl)erbium (Er(EtCp) 3 ). Morphological change of an ErP layer on InP(0 0 1) is investigated together with that of an overgrown capping InP layer. Optimum growth condition of InP causes islanding on over-monolayer-ErP. A relatively low overgrowth temperature of InP is a key factor for attaining complete capping coverage on ErP

Enhanced photovoltaic performance of dye-sensitized solar cells based on NaYF4:Yb(3+), Er(3+)-incorporated nanocrystalline TiO2 electrodes.

Science.gov (United States)

Zhu, Guang; Wang, Hongyan; Zhang, Quanxin; Zhang, Li

2015-08-01

Near infrared to visible up-conversion of light by rare earth ion-doped phosphors (NaYF4:Yb(3+), Er(3+)) that convert multiple photons of lower energy to higher energy photons offer new possibilities for improved performance of photovoltaic devices. Here, up-conversion phosphor NaYF4:Yb(3+), Er(3+) doped nanocrystalline TiO2 films are designed and used as a electrode for dye-sensitized solar cells, and the photovoltaic performance of DSSCs based on composite electrodes are investigated. The results show the cell with NaYF4:Yb(3+), Er(3+) achieves a power conversion efficiency of 7.65% under one sun illumination (AM 1.5G, 100mWcm(-2)), which is an increase of 14% compared to the cell without NaYF4:Yb(3+), Er(3+) (6.71%). The performance improvement is attributed to the dual effects of enhanced light harvesting from extended light absorption range and increased light scattering, and lower electron transfer resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser.

Science.gov (United States)

Kisel, V E; Gorbachenya, K N; Yasukevich, A S; Ivashko, A M; Kuleshov, N V; Maltsev, V V; Leonyuk, N I

2012-07-01

We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W. By using Co(2+):MgAl(2)O(4) as a saturable absorber, a TEM(00)-mode Q-switched average output power of 315 mW was demonstrated at 1522 nm, with pulse duration of 5 ns and pulse energy of 5.25 μJ at a repetition rate of 60 kHz.

Photonic band edge assisted spontaneous emission enhancement from all Er3+ 1-D photonic band gap structure

Science.gov (United States)

Chiasera, A.; Meroni, C.; Varas, S.; Valligatla, S.; Scotognella, F.; Boucher, Y. G.; Lukowiak, A.; Zur, L.; Righini, G. C.; Ferrari, M.

2018-06-01

All Er3+ doped dielectric 1-D Photonic Band Gap Structure was fabricated by rf-sputtering technique. The structure was constituted by of twenty pairs of SiO2/TiO2 alternated layers doped with Er3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements put in evidence the stop band in the range 1500 nm-1950 nm. The photoluminescence measurements were obtained by optically exciting the sample and detecting the emitted light in the 1.5 μm region at different detection angles. Luminescence spectra and luminescence decay curves put in evidence that the presence of the stop band modify the emission features of the Er3+ ions.

Visible and NIR luminescence of nanocrystalline β-Ga2O3:Er3+ prepared by solution combustion synthesis

International Nuclear Information System (INIS)

Biljan, Tomislav; Gajovic, Andreja; Meic, Zlatko

2008-01-01

In this paper we report on facile solution combustion synthesis of erbium doped β-Ga 2 O 3 with urea as fuel. The product was characterized using powder X-ray diffraction and transmission electron microscopy (TEM). X-ray diffraction and TEM showed that the material is nanostructured. Luminescence properties of β-Ga 2 O 3 :Er are studied with excitation in near infrared (Nd:YAG laser at 1064 nm) and visible (argon laser at 514.5 nm). A strong NIR emission of Er 3+ in the window of minimal optical loss in silica based optical fibers, due to the 4 I 13/2 → 4 I 15/2 transition at 1.55 μm has been observed. Codoping with Yb 3+ significantly increases the intensity of that important emission

Nanocrystal in Er3+-doped SiO2-ZrO2 Planar Waveguide with Yb3+ Sensitizer

International Nuclear Information System (INIS)

Razaki, N. Iznie; Jais, U. Sarah; Abd-Rahman, M. Kamil; Bhaktha, S. N. B.; Chiasera, A.; Ferrari, M.

2010-01-01

Higher doping of Er 3+ in glass ceramic waveguides would cause concentration and pair-induced quenching which lead to inhomogeneous line-width of luminescence spectrum thus reduce output intensity. Concentration quenching can be overcome by introducing ZrO 2 in the glass matrix while co-doping with Yb 3+ which acts as sensitizer would improve the excitation efficiency of Er 3+ . In this study, SiO 2 -ZrO 2 planar waveguides having composition in mol percent of 70SiO 2 -30ZrO 2 doped with Er 3+ and co-doped with Yb 3+ , were prepared via sol-gel route. Narrower and shaper peaks of PL and XRD shows the formation of nanocrystals. Intensity is increase with addition amount of Yb 3+ shows sensitizing effect on Er 3+ .

Green, red and near-infrared photon up-conversion in Ga–Ge–Sb–S:Er{sup 3+} amorphous chalcogenides

Energy Technology Data Exchange (ETDEWEB)

Strizik, L., E-mail: lukas.strizik@centrum.cz [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice (Czech Republic); Zhang, J. [Division of Advanced Nuclear Engineering, Center for Information Materials, Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Wagner, T. [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice (Czech Republic); Oswald, J. [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, 16200 Prague (Czech Republic); Kohoutek, T. [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice (Czech Republic); Walsh, B.M. [NASA Langley Research Center, Hampton, VA 23681 (United States); Prikryl, J. [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice (Czech Republic); Svoboda, R. [Department of Physical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice (Czech Republic); Liu, C. [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, 122 Luoshi Road, Hongshan, Wuhan, Hubei 430070 (China); Frumarova, B. [Institute of Macromolecular Chemistry of Czech Academy of Sciences, v.v.i., Heyrovskeho nam. 2, Prague (Czech Republic); Frumar, M. [Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice (Czech Republic); Pavlista, M. [Department of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, Studentska 84, 53210 Pardubice (Czech Republic); and others

2014-03-15

We report on compositional tuning in Er{sup 3+} ions doped Ga–Ge–Sb–S glassy system allowing for effective {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2} (530 nm), {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} (550 nm), {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} (660 nm), {sup 4}I{sub 9/2}→{sup 4}I{sub 15/2} (810 nm), {sup 4}I{sub 11/2}→{sup 4}I{sub 15/2} (990 nm) intra-4f electronic transition emissions of Er{sup 3+} ions under 808 nm, 980 nm or 1550 nm laser pumping. We changed the composition of well-known Ge{sub 20}Ga{sub 5}Sb{sub 10}S{sub 65} glass to Ge{sub 25}Ga{sub 10−x}Sb{sub x}S{sub 65}, where x=0.5 at%, 2.5 at% or 5.0 at% and doped it with 0.5 at% of Er{sup 3+} ions. The short-wavelength absorption edge of the studied glassy hosts is blue-shifted by substitution of Sb with Ga to ∼500 nm making the green emission at 530 nm and 550 nm and even 495 nm ({sup 4}F{sub 7/2}→{sup 4}I{sub 15/2}) observable, while the glass stability was kept high characterized with the difference of T{sub c}−T{sub g}>100 K and mean coordination numbers 2.67–2.71. Up-conversion emission decay times of all anti-Stokes emissions were in the range of 0.2–2.1 ms. The influence of Ga substitution with Sb on the structure and the optical properties was investigated. The spectroscopic parameters for Er{sup 3+} ions with local environment change were analyzed based on Judd–Ofelt theory. -- Highlights: • Compositional tuning of Ga–Ge–Sb–S:Er{sup 3+} phosphor leads to efficient photon up-conversion under 808 nm, 980 nm and 1550 nm laser pumping. • The 530 nm, 550 nm, 660 nm, 810 nm and 990 nm up-conversion emission bands were detected and their lifetimes determined. • Judd–Ofelt theory was used to study the Er{sup 3+} local environment in Ga–Ge–Sb–S glassy host matrix. • Thermally stable chalcogenide Ga–Ge–Sb–S:Er{sup 3+} phosphors are proposed as candidates for up-converting layers enhancing the silicon solar cell efficiency.

Down- and up-conversion emissions in Er{sup 3+}–Yb{sup 3+} codoped TeO{sub 2}–ZnO–ZnF{sub 2} glasses

Energy Technology Data Exchange (ETDEWEB)

Miguel, A. [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013 Bilbao (Spain); Arriandiaga, M.A. [Departamento de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apartado 644, Bilbao (Spain); Morea, R. [Instituto de Optica, Consejo Superior de Investigaciones Científicas CSIC, Serrano 121, 28006 Madrid (Spain); Fernandez, J. [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013 Bilbao (Spain); Materials Physics Center CSIC-UPV/EHU and Donostia International Physics Center, 20018 San Sebastian (Spain); Gonzalo, J. [Instituto de Optica, Consejo Superior de Investigaciones Científicas CSIC, Serrano 121, 28006 Madrid (Spain); Balda, R., E-mail: wupbacrr@bi.ehu.es [Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alda. Urquijo s/n, 48013 Bilbao (Spain); Materials Physics Center CSIC-UPV/EHU and Donostia International Physics Center, 20018 San Sebastian (Spain)

2015-02-15

In this work, we report the near infrared and upconversion emissions of Er{sup 3+}–Yb{sup 3+} codoped fluorotellurite TeO{sub 2}–ZnO–ZnF{sub 2} glasses for different YbF{sub 3} concentrations ranging between 0.5 and 2 wt%. The study includes absorption and emission spectra and lifetime measurements for the infrared and visible fluorescence. The energy transfer between Yb{sup 3+} and Er{sup 3+} ions is confirmed by the temporal behavior of the near-infrared luminescence of Yb{sup 3+} ions as well as by the enhancement of the 1532 nm emission of Er{sup 3+} ions in the codoped samples. The Yb{sup 3+}→Er{sup 3+} energy transfer efficiency is calculated from the Yb{sup 3+} lifetimes in single and codoped samples. Back transfer from Er{sup 3+} to Yb{sup 3+} ions is present under near infrared and visible excitation of Er{sup 3+} ions at 798 and 488 nm respectively. An enhancement of the visible upconversion fluorescence is also observed in the codoped samples due to energy transfer from Yb{sup 3+} to Er{sup 3+} ions. The standardized value for the efficiency of the green upconversion emission is 1.06×10{sup −4} for the codoped sample with 2 wt% of YbF{sub 3} which is comparable to that reported in lead–zinc–tellurite glasses. The possible upconversion processes and mechanisms leading to the population of several excited levels are discussed. - Highlights: • The effect of Yb{sup 3+} concentration on the NIR and VIS emissions of Er{sup 3+}ions is studied. • TheYb{sup 3+}↔Er{sup 3+} energy transfer in fluorotellurite glasses is demonstrated. • Increase of the green upconversion emission with Yb{sup 3+} concentration due to Yb{sup 3+}→Er{sup 3+} energy transfer. • The ratio of red to green upconversion emissions depends on the concentration of Yb{sup 3+} ions.

UV and gamma ray induced thermoluminescence properties of cubic Gd2O3:Er3+ phosphor

Directory of Open Access Journals (Sweden)

Raunak Kumar Tamrakar

2014-10-01

Full Text Available This paper reports the thermoluminescence properties of Er3+ doped gadolinium oxide nanophosphor. The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production. Starting materials used for sample preparation were Gd2O3, Er2O3 (0.5–2.5 mol% and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor is determined by scanning electron microscopic (SEM technique. Functional group analysis was done by Fourier transform infra-red spectroscopy (FTIR analysis. The elemental analysis of prepared sample was determined by energy dispersive X-ray analysis (EDX and the exact particle size of prepared phosphor for the different concentration of dopant (Er3+ was evaluated by transmission electron microscopy (TEM technique. The prepared phosphors for different concentration of Er3+ were examined by thermoluminescence (TL glow curve for UV and gamma irradiation. The UV 254 nm source was used for UV irradiation and Co60 source was used for gamma irradiation. The samples show well resolved broad peak covered the temperature range 50–250 °C and the peak temperature found at 126 °C for UV irradiation and higher temperature peak at 214 °C for gamma irradiation. The effect of heating rate on TL studies was presented for optimized sample. Here UV irradiated sample shows the formation of shallow trap (surface trapping and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma and UV exposure on TL studies was also examined and it shows linear

Bright white upconversion luminescence from Er3+/Tm3+/Yb3+-doped titanate-based glasses prepared by aerodynamic levitation method

Science.gov (United States)

Zhang, Minghui; Yu, Jianding; Jiang, Wan; Liu, Yan; Ai, Fei; Wen, Haiqin; Jiang, Meng; Yu, Huimei; Pan, Xiuhong; Tang, Meibo; Gai, Lijun

2017-10-01

Aerodynamic levitation method was employed to prepare Er3+/Tm3+/Yb3+-doped titanate-based glasses. DTA results show that the glass performs high thermal stability with the glass transition temperature of 799 °C. The interaction among rare earth ions has been discussed by adjusting the relative concentration. Er3+ ions can quench the upconversion luminescence of Tm3+ ions. Tm3+ ions play a strong role in quenching the emissions of Er3+ and Tm3+ when the content of Tm3+ ions is greater than or equal 0.05. From the view of the ratio of red emission to green emission, Tm3+ ions can improve the red emission of Er3+ ions to some extent in contrast with the green emissions of Er3+ ions. 980 nm incident laser can be efficiently absorbed by Yb3+ ions. The relative intensity of red, green, and blue upconversion luminescence has been tuned to obtain white light. The composition with white upconversion luminescence of the color coordinate (0.291, 0.3292) has been found. Moreover, white upconversion luminescence mechanism is a two-photon process of ET, ESA, and cooperative sensitization. Rare earth ions doped titanate-based glasses with bright upconversion luminescence perform potential applications in color display, back light, et al.

Bell-shaped calcium-response curves of lns(l,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum

Science.gov (United States)

Bezprozvanny, Llya; Watras, James; Ehrlich, Barbara E.

1991-06-01

RELEASE of calcium from intracellular stores occurs by two pathways, an inositol 1,4,5-trisphosphate (InsP3)-gated channel1-3 and a calcium-gated channel (ryanodine receptor)4-6. Using specific antibodies, both receptors were found in Purkinje cells of cerebellum7,8. We have now compared the functional properties of the channels corresponding to the two receptors by incorporating endoplasmic reticulum vesicles from canine cerebellum into planar bilayers. InsP3-gated channels were observed most frequently. Another channel type was activated by adenine nucleotides or caffeine, inhibited by ruthenium red, and modified by ryanodine, characteristics of the ryanodine receptor/channel6. The open probability of both channel types displayed a bell-shaped curve for dependence on calcium. For the InsP3-gated channel, the maximum probability of opening occurred at 0.2 µM free calcium, with sharp decreases on either side of the maximum. Maximum activity for the ryanodine receptor/channel was maintained between 1 and 100 µM calcium. Thus, within the physiological range of cytoplasmic calcium, the InsP3-gated channel itself allows positive feed-back and then negative feedback for calcium release, whereas the ryanodine receptor/channel behaves solely as a calcium-activated channel. The existence in the same cell of two channels with different responses to calcium and different ligand sensitivities provides a basis for complex patterns of intracellular calcium regulation.

Enhanced frequency upconversion study in Er3+/Yb3+ doped/codoped TWTi glasses

Science.gov (United States)

Azam, Mohd; Rai, Vineet Kumar

2018-04-01

Er3+/Yb3+ doped/codoped TeO2-WO3-TiO2 (TWTi) glasses have been prepared by using the melt-quenching technique. The upconversion (UC) emission spectra of the developed glasses have been recorded upon 980 nm laser excitation. Three intense UC emission bands have been observed within the green and red region centered at ˜532 nm, ˜553 nm and ˜669 nm corresponding to the 2H11/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions respectively in the singly Er3+ doped glass. On introducing Yb3+ ions in the singly Er3+ doped glass, an enhancement of about ˜ 12 times and ˜50 times in the green and red bands respectively have been observed even at low pump power ˜ 364 mW followed by two photon absorption process. Colour tunability from yellowish green to pure green colour region has been observed on varying the pump power. The prepared glass can be used to produce NIR to green upconverter and colour tunable display devices.

The 5’cap of Tobacco Mosaic Virus (TMV) is required for virion attachment to the actin/ER network during early infection

DEFF Research Database (Denmark)

Christensen, Nynne Meyn; Tilsner, Jens; Bell, Karen

to the motile cortical actin/ER network within minutes of injection. Granule movement on actin/ER was arrested by actin inhibitors indicating actindependent RNA movement. The 5’ methylguanosine TMV cap was shown to be required for vRNA anchoring to the ER. TMV vRNA lacking the 5’cap failed to form granules...... the fluorescent vRNA pool nor co-injected GFP left the injected trichome, indicating that the synthesis of unlabelled progeny viral (v)RNA is required to initiate cell-cell movement, and that virus movement is not accompanied by passive plasmodesmatal gating. Cy3-vRNA formed granules that became anchored...... on the same ER-bound granules, indicating that TMV virions may become attached to the ER prior to uncoating of the viral genome....

NIR to visible upconversion in Er3+/Yb3+ co-doped CaYAl3O7 phosphor obtained by solution combustion process

International Nuclear Information System (INIS)

Singh, Vijay; Rai, Vineet Kumar; Al-Shamery, Katharina; Nordmann, Joerg; Haase, Markus

2011-01-01

Using the combustion synthesis, CaYAl 3 O 7 :Er 3+ phosphor powders co-doped with Yb 3+ have been prepared at low temperatures (550 o C) in a few minutes. Formation of the compound was confirmed by X-ray powder diffraction. Near-infrared to visible upconversion fluorescence emission in the Er 3+ doped CaYAl 3 O 7 phosphor powder has been observed. The effect of co-doping with triply ionized ytterbium in the CaYAl 3 O 7 :Er 3+ phosphor has been studied and the process involved is discussed. - Highlights: → The green emitting up-conversion CaYAl 3 O 7 :Er 3+ phosphor powders co-doped with Yb 3+ have been prepared by easy combustion method. → The combustion method is a simple, energy saving, fast and economical viable process. → The luminescence intensity in the co-doped phosphor is enhanced by several times compared to that of the singly (Er 3+ ) doped phosphor.

Increased anion channel activity is an unavoidable event in ozone-induced programmed cell death.

Directory of Open Access Journals (Sweden)

Takashi Kadono

Full Text Available BACKGROUND: Ozone is a major secondary air pollutant often reaching high concentrations in urban areas under strong daylight, high temperature and stagnant high-pressure systems. Ozone in the troposphere is a pollutant that is harmful to the plant. PRINCIPAL FINDINGS: By exposing cells to a strong pulse of ozonized air, an acute cell death was observed in suspension cells of Arabidopsis thaliana used as a model. We demonstrated that O(3 treatment induced the activation of a plasma membrane anion channel that is an early prerequisite of O(3-induced cell death in A. thaliana. Our data further suggest interplay of anion channel activation with well known plant responses to O(3, Ca(2+ influx and NADPH-oxidase generated reactive oxygen species (ROS in mediating the oxidative cell death. This interplay might be fuelled by several mechanisms in addition to the direct ROS generation by O(3; namely, H(2O(2 generation by salicylic and abscisic acids. Anion channel activation was also shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during programmed cell death. SIGNIFICANCE: Collectively, our data indicate that anion efflux is an early key component of morphological and biochemical events leading to O(3-induced programmed cell death. Because ion channels and more specifically anion channels assume a crucial position in cells, an understanding about the underlying role(s for ion channels in the signalling pathway leading to programmed cell death is a subject that warrants future investigation.

Isothermal section of the Er-Fe-Al ternary system at 800 oC

International Nuclear Information System (INIS)

Jemmali, M.; Walha, S.; Pasturel, M.; Tougait, O.; Ben Hassen, R.; Noel, H.

2010-01-01

Physico-chemical analysis techniques, including X-ray diffraction and Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy, were employed to construct the isothermal section of the Er-Fe-Al system at 800 o C. At this temperature, the phase diagram is characterized by the formation of five intermediate phases, ErFe 12-x Al x with 5 ≤ x ≤ 8 (ThMn 12 -type), ErFe 1+x Al 1-x with -0.2 ≤ x ≤ 0.75 (MgZn 2 -type), ErFe 3-x Al x with 0.5 2 Al-type), Er 2 Fe 17-x Al x with 4.74 ≤ x ≤ 5.7 (TbCu 7 -type) and Er 2 Fe 17-x Al x with 5.7 2 Zn 17 -type), seven extensions of binaries into the ternary system; ErFe x Al 3-x with x 3 Cu-type), ErFe x Al 2-x with x ≤ 0.68 (MgCu 2 -type), Er 2 Fe x Al 1-x with x ≤ 0.25 (Co 2 Si-type), ErFe 2-x Al x with x ≤ 0.5 (MgCu 2 -type), ErFe 3-x Al x with x ≤ 0.5 (Be 3 Nb-type), Er 6 Fe 23-x Al x with x ≤ 8 (Th 6 Mn 23 -type), and Er 2 Fe 17-x Al x with x ≤ 4.75 (Th 2 Ni 17 -type) and one intermetallic compound; the ErFe 2 Al 10 (YbFe 2 Al 10 -type).

MIT HJEM ER HVOR MIT HJERTE ER

DEFF Research Database (Denmark)

Høst, Jeppe Engset

2014-01-01

Ideen om at arbejde med det man kalder de stedbundne ressourcer på en ny måde, er relevant på Bornholm hvor events som blandt andet festivalen ’Wonderfestiwall’, strandfesten ’Vang Pier Beach Party’, karnevallet ’Svaneke Beach Party, kokkekonkurrencen ’Sol over Gudhjem’ og filmfestivalen ’Bornsho...

Optical decoherence and persistent spectral hole burning in Er3+:LiNbO3

International Nuclear Information System (INIS)

Thiel, C.W.; Macfarlane, R.M.; Boettger, T.; Sun, Y.; Cone, R.L.; Babbitt, W.R.

2010-01-01

Developing new resonant optical materials for spatial-spectral holography and quantum information applications requires detailed knowledge of the decoherence and population relaxation dynamics for the quantum states involved in the optical transitions, motivating the need for fundamental material studies. We report recent progress in studying these properties in erbium-doped lithium niobate at liquid helium temperatures. The influence of temperature, applied magnetic fields, measurement timescale, and dopant concentration were probed using photon echo spectroscopy and time-resolved spectral hole burning on the 1532 nm transition of Er 3+ :LiNbO 3 . Effects of spectral diffusion due to interactions between Er 3+ ions and between the Er 3+ ion and 7 Li and 93 Nb nuclear spins in the host lattice were observed. In addition, long-lived persistent spectral storage of seconds to minutes was observed due to non-equilibrium population redistribution among superhyperfine states.

Er3+ impurities in KTiOPO4 studied by electron paramagnetic resonance

International Nuclear Information System (INIS)

Bravo, D; MartIn, A; Carvajal, J J; Aguilo, M; DIaz, F; Lopez, F J

2006-01-01

An electron paramagnetic resonance (EPR) study of Er 3+ ions in single crystals of KTiOPO 4 (KTP) is presented. The EPR spectra show the existence of eight different Er 3+ centres. The g-matrix has been determined for all eight centres from the analysis of the angular dependences of the spectrum in three planes of the crystal. This study provides strong evidence about incorporation of erbium in the low-symmetry K + sites of KTP. Possible reasons for the appearance of such a large number of Er 3+ centres are discussed

Upconversion photoluminescence of epitaxial Yb{sup 3+}/Er{sup 3+} codoped ferroelectric Pb(Zr,Ti)O{sub 3} films on silicon substrates

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yang, E-mail: zhangy_acd@hotmail.com [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Kämpfe, Thomas [Institut für Angewandte Physik, TU Dresden, 01062 Dresden (Germany); Bai, Gongxun [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Mietschke, Michael; Yuan, Feifei; Zopf, Michael [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Abel, Stefan [IBM Research GmbH, Saümerstrasse 4, 8803 Rüschlikon (Switzerland); Eng, Lukas M. [Institut für Angewandte Physik, TU Dresden, 01062 Dresden (Germany); Hühne, Ruben [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Fompeyrine, Jean [IBM Research GmbH, Saümerstrasse 4, 8803 Rüschlikon (Switzerland); Ding, Fei, E-mail: f.ding@ifw-dresden.de [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Schmidt, Oliver G. [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer strasse 70, 09107 Chemnitz (Germany)

2016-05-31

Thin films of Yb{sup 3+}/Er{sup 3+} codoped Pb(Zr,Ti)O{sub 3} (PZT:Yb/Er) have been epitaxially grown on the SrTiO{sub 3} buffered Si wafer by pulsed laser deposition. Strong upconversion photoluminescence was observed in the PZT:Yb/Er thin film. Using piezoresponse force microscopy, polar domains in the PZT:Yb/Er film can be reversibly switched with a phase change of 180°. Ferroelectric hysteresis loop shape with a well-saturated response was observed. The epitaxially grown lanthanide-doped PZT on silicon opens up a promising route to the integration of luminescent functional oxides on the silicon platform. - Highlights: • Epitaxial growth of Yb{sup 3+}/Er{sup 3+} codoped Pb(Zr,Ti)O{sub 3} films on SrTiO{sub 3} buffered silicon • Upconversion emissions were obtained from the lanthanide ion doped thin films. • Saturated ferroelectric hysteresis loops were observed. • Polar domains were switched by PFM with a phase change of 180°.

Upconversion emission and cathodoluminescence of Er"3"+-doped NaYbF_4 nanoparticles for low-temperature thermometry and field emission displays

International Nuclear Information System (INIS)

Du, Peng; Yu, Jae Su; Luo, Laihui

2017-01-01

The Er"3"+-doped NaYbF_4 nanoparticles were fabricated by a hydrothermal method. The green and red emissions located at around 525, 542 and 657 nm corresponding to the "2H_1_1_/_2 → "4I_1_5_/_2, "4S_3_/_2 → "4I_1_5_/_2 and "4F_9_/_2 → "4I_1_5_/_2 transitions of Er"3"+ ions, respectively, were observed when pumped at 980 nm light. Furthermore, with the help of the fluorescence intensity ratio technique, the thermometric properties of as-prepared products from the thermally coupled "2H_1_1_/_2 and "4S_3_/_2 levels of Er"3"+ ions were studied by analyzing temperature-dependent upconversion (UC) emission spectra. The maximum sensitivity for the Er"3"+-doped NaYbF_4 nanoparticles was found to be around 0.0043 K"- "1 with a temperature range of 93-293 K. In addition, the cathodoluminescence (CL) spectrum of the synthesized nanoparticles was nearly the same as the UC emission spectrum and the CL emission intensity did not exhibit saturation with the increase of accelerating voltage and filament current. (orig.)

Spectral and laser properties of Er3+/Yb3+/Ce3+ tri-doped Ca3NbGa3Si2O14 crystal at 1.55 µm

Science.gov (United States)

Gong, Guoliang; Chen, Yujin; Lin, Yanfu; Huang, Jianhua; Gong, Xinghong; Luo, Zundu; Huang, Yidong

2018-04-01

An Er3+/Yb3+/Ce3+ tri-doped Ca3NbGa3Si2O14 (CNGS) crystal was grown by the Czochralski method. Spectral properties of the crystal, including the polarized absorption and fluorescence spectra, the fluorescence decay, as well as the energy transfer efficiency from Yb3+ to Er3+ were investigated in detail. End-pumped by a 976 nm diode laser, a 1556 nm continuous-wave laser with a maximum output power of 202 mW and a slope efficiency of 11.4% was achieved in the Er,Yb,Ce:CNGS crystal. The results indicate the Er,Yb,Ce:CNGS crystal is a promising 1.55 µm laser gain medium.

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 ...

Modeling of Yb3+-sensitized Er3+-doped silica waveguide amplifiers

DEFF Research Database (Denmark)

Lester, Christian; Bjarklev, Anders Overgaard; Rasmussen, Thomas

1995-01-01

A model for Yb3+-sensitized Er3+-doped silica waveguide amplifiers is described and numerically investigated in the small-signal regime. The amplified spontaneous emission in the ytterbium-band and the quenching process between excited erbium ions are included in the model. For pump wavelengths...

∼2 μm fluorescence radiative dynamics and energy transfer between Er3+ and Tm3+ ions in silicate glass

International Nuclear Information System (INIS)

Li, Ming; Liu, Xueqiang; Guo, Yanyan; Hao, Wei; Hu, Lili; Zhang, Junjie

2014-01-01

Graphical abstract: - Highlights: • A Er 3+ /Tm 3+ co-doped silicate glass with good thermal stability (k gl = 0.402 for STE glass) is prepared. • Efficient ∼2 μm emission is observed under 808 nm and 980 nm laser excitation. • The glass structure and spectroscopic properties are confirmed by optical absorption, IR transmission, Raman and fluorescence studies. • The content of OH groups deceases efficiently after fluorine ions are introduced. • The energy transfer coefficient from Er 3+ to Tm 3+ in STFE glass is 13.39 × 10 −40 cm 6 /s. - Abstract: A Er 3+ /Tm 3+ co-doped silicate glass with good thermal stability is prepared by melt-quenching method. An efficient emission of ∼2 μm is observed under different selective laser excitations. The optical absorption and transmission spectra, Raman spectra, and emission spectra are tested to characterize ∼2 μm emission properties of Er 3+ /Tm 3+ co-doped silicate glasses and a reasonable energy transfer mechanism of ∼2 μm emission between Er 3+ and Tm 3+ ions is proposed. Based on the optical absorption spectra, the Judd–Ofelt parameters and radiative properties were calculated. Intense ∼2 μm emission is obtained from Er 3+ /Tm 3+ co-doped silicate glasses due to the efficient energy transfer from Er 3+ to Tm 3+ ions. The energy transfer coefficient from Er 3+ to Tm 3+ ions can reach as high as 13.39 × 10 −40 cm 6 /s. In addition, the population of the OH groups is decreased and the ∼2 μm emission is effectively enhanced with fluoride introduction. The emission property, together with good thermal property, indicates that Er 3+ /Tm 3+ co-doped silicate glass is a potential kind of laser glass for efficient ∼2 μm laser

Effect of the SK/IK channel modulator 4,5-dichloro-1,3-diethyl-1,3-dihydro-benzoimidazol-2-one (NS4591) on contractile force in rat, pig and human detrusor smooth muscle

DEFF Research Database (Denmark)

Nielsen, Jens Steen; Rode, Frederik; Rahbek, Mette

2011-01-01

• To investigate the importance of small (SK)- and intermediate (IK)-conductance Ca2(+) -activated K(+) channels on bladder function, by studying the effects of 4,5-dichloro-1,3-diethyl-1,3-dihydro-benzoimidazol-2-one (NS4591), a new modulator of SK/IK channels, on contractions induced by electri......• To investigate the importance of small (SK)- and intermediate (IK)-conductance Ca2(+) -activated K(+) channels on bladder function, by studying the effects of 4,5-dichloro-1,3-diethyl-1,3-dihydro-benzoimidazol-2-one (NS4591), a new modulator of SK/IK channels, on contractions induced...

Suppression effect of silicon (Si on Er3+ 1.54μm excitation in ZnO thin films

Directory of Open Access Journals (Sweden)

Bo Xu

2016-08-01

Full Text Available We have investigated the photoluminescence (PL characteristics of ZnO:Er thin films on Si (100 single crystal and SiO2-on-silicon (SiO2 substrates, synthesized by radio frequency magnetron sputtering. Rutherford backscattering/channeling spectrometry (RBS, X-ray diffraction (XRD and atomic force microscope (AFM were used to analyze the properties of thin films. The diffusion depth profiles of Si were determined by second ion mass spectrometry (SIMS. Infrared spectra were obtained from the spectrometer and related instruments. Compared with the results at room temperature (RT, PL (1.54μm intensity increased when samples were annealed at 250°C and decreased when at 550°C. A new peak at 1.15μm from silicon (Si appeared in 550°C samples. The Si dopants in ZnO film, either through the diffusion of Si from the substrate or ambient, directly absorbed the energy of pumping light and resulted in the suppression of Er3+ 1.54μm excitation. Furthermore, the energy transmission efficiency between Si and Er3+ was very low when compared with silicon nanocrystal (Si-NC. Both made the PL (1.54μm intensity decrease. All the data in experiments proved the negative effects of Si dopants on PL at 1.54μm. And further research is going on.

Measurement of 167Er(n,p)167Ho reaction at 13.5 and 14.8 MeV

International Nuclear Information System (INIS)

Luo, Junhua; Liu, Jun; Han, Jiuning; Jiang, Li; Liu, Rong; Ge, Suhong; Liu, Zhenlai

2013-01-01

We have measured the 167 Er(n,p) 167 Ho cross-sections at two different neutron energies 13.5 and 14.8 MeV. Measurements were performed at Pd-300 neutron generator of Chinese Academy of Engineering Physics (CAEP) with monoenergetic neutrons produced via the 3 H(d,n) 4 He reaction using a tritium–titanium (T–Ti) target. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with high-purity germanium (HPGe) detector. The data for 167 Er(n,p) 167 Ho reaction cross-sections are reported to be 2.2±0.6 and 2.8±1.4 mb at 13.5±0.2 and 14.8±0.2 MeV incident neutron energies, respectively. The cross sections were also estimated with the TALYS-1.4 nuclear model code and compared with experimental data found in the literature, and with the comprehensive evaluation data in ENDF/B-VII.1 and JEFF-3.1/A libraries. - Highlights: • D–T neutron source was used to measure cross sections using activation method. • 27 Al(n,α) 24 Na was used as the monitor for the measurement. • The cross sections for the 167 Er(n,p) 167 Ho reactions have been measured. • Contribution of the interfering reaction 170 Er(n,α) 167 Dy was subtracted. • The results were compared with previous data and with evaluation data

Lattice sites and stability of implanted Er in FZ and CZ Si

CERN Document Server

Wahl, U; Langouche, G; Vantomme, A

1998-01-01

We report on the lattice location of $^{167}$Er in Si measured by conversion electron emission channeling. In both FZ and CZ Si, a high fraction of Er (>65%) occupies near-tetrahedral interstitial (T) sites directly following 60 keV room temperature implantation at doses of 6 $\\times 10^{12}$ cm$^{-2}$. For higher doses, the as-implanted near-T fractions of Er visible by emission channeling are smaller, due to the beginning of amorphization. Following the recovery of implantation damage at 600°C, more than 70% of Er is found on near-T sites in both FZ and CZ Si. In FZ Si, Er exhibits a remarkable thermal stability and only prolonged annealing for several hours reduces the near-T fraction. On the other hand, annealing of CZ Si at 900°C for more than 10 minutes results in the majority of Er probes in sites of very low symmetry or disordered surroundings.

Radiation hardening in sol-gel derived Er3+-doped silica glasses

International Nuclear Information System (INIS)

Hari Babu, B.; León Pichel, Mónica; Ollier, Nadège; El Hamzaoui, Hicham; Bigot, Laurent; Savelii, Inna; Bouazaoui, Mohamed; Poumellec, Bertrand; Lancry, Matthieu; Ibarra, Angel

2015-01-01

The aim of the present paper is to report the effect of radiation on the Er 3+ -doped sol-gel silica glasses. A possible application of these sol-gel glasses could be their use in harsh radiation environments. The sol-gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol-gel technique. The radiation-induced attenuation of Er 3+ -doped sol-gel silica is found to increase with erbium content. Electron paramagnetic resonance studies reveal the presence of E′ δ point defects. This happens in the sol-gel aluminum-silica glass after an exposure to γ-rays (kGy) and in sol-gel silica glass after an exposure to electrons (MGy). The concentration levels of these point defects are much lower in γ-ray irradiated sol-gel silica glasses. When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er 3+ to Er 2+ ions. This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects

Led strategisk med 3 F'er

DEFF Research Database (Denmark)

Klausen, Kurt Klaudi

2017-01-01

Artiklen gennemgår kort de tre F'er: at fremskrive, forudse og forestille som strategiske værktøjer til strategic forecast......Artiklen gennemgår kort de tre F'er: at fremskrive, forudse og forestille som strategiske værktøjer til strategic forecast...

A ₂ TiO ₅ (A = Dy, Gd, Er, Yb) at High Pressure

Energy Technology Data Exchange (ETDEWEB)

Park, Sulgiye [Department of Geological Science, Stanford University, Stanford, California 94305, United States; Rittman, Dylan R. [Department of Geological Science, Stanford University, Stanford, California 94305, United States; Tracy, Cameron L. [Department of Geological Science, Stanford University, Stanford, California 94305, United States; Chapman, Karena W. [X-ray Science Division, Advanced Photon; Zhang, Fuxiang [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States; Park, Changyong [HPCAT, Carnegie Institution of Washington, Argonne, Illinois 60439, United States; Tkachev, Sergey N. [Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, United States; O’Quinn, Eric [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States; Shamblin, Jacob [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States; Lang, Maik [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States; Mao, Wendy L. [Department of Geological Science, Stanford University, Stanford, California 94305, United States; Stanford; amp, Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States; Ewing, Rodney C. [Department of Geological Science, Stanford University, Stanford, California 94305, United States

2018-02-07

The structural evolution of lanthanide A2TiO5 (A = Dy, Gd, Yb, and Er) at high pressure is investigated using synchrotron X-ray diffraction. The effects of A-site cation size and of the initial structure are systematically examined by varying the composition of the isostructural lanthanide titanates, and the structure of dysprosium titanate polymorphs (orthorhombic, hexagonal and cubic), respectively. All samples undergo irreversible high pressure phase transformations, but with different onset pressures depending on the initial structure. While individual phase exhibits different phase transformation histories, all samples commonly experience a sluggish transformation to a defect cotunnite-like (Pnma) phase for a certain pressure range. Orthorhombic Dy2TiO5 and Gd2TiO5 form P21am at pressures below 9 GPa and Pnma above 13 GPa. Pyrochlore-type Dy2TiO5 and Er2TiO5 as well as defect-fluorite-type Yb2TiO5 form Pnma at ~ 21 GPa, followed by Im-3m. Hexagonal Dy2TiO5 forms Pnma directly, although a small amount of remnants of hexagonal Dy2TiO5 is observed even at the highest pressure (~ 55 GPa) reached, indicating a kinetic limitations in the hexagonal Dy2TiO5 phase transformations at high pressure. Decompression of these materials leads to different metastable phases. Most interestingly, a high pressure cubic X-type phase (Im-3m) is confirmed using highresolution transmission electron microscopy on recovered pyrochlore-type Er2TiO5. The kinetic constraints on this metastable phase yield a mixture of both the X-type phase and amorphous domains upon pressure release. This is the first observation of an X-type phase for an A2BO5 composition at high pressure.

Experimental investigation and crystal-field modeling of Er{sup 3+} energy levels in GSGG crystal

Energy Technology Data Exchange (ETDEWEB)

Gao, J.Y., E-mail: jygao1985@sina.com [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Sun, D.L.; Zhang, Q.L. [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Wang, X.F. [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Liu, W.P.; Luo, J.Q.; Sun, G.H.; Yin, S.T. [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China)

2016-06-25

The Er{sup 3+}-doped Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} (Er{sup 3+}:GSGG) single crystal, a excellent medium of the mid-infrared and anti-radiation solid state laser pumped by laser diode, was grown by Czochralski method successfully. The absorption spectra were measured and analyzed in a wider spectral wavelength range of 350–1700 nm at different temperatures of 7.6, 77, 200 and 300 K. The free-ions and crystal-field parameters were fitted to the experimental energy levels with the root mean square deviation of 9.86 cm{sup −1}. According to the crystal-field calculations, 124 degenerate energy levels of Er{sup 3+} in GSGG host crystals were assigned. The fitting results of free-ions and crystal-field parameters were compared with those already reported of Er{sup 3+}:YSGG. The results indicated that the free-ions parameters for Er{sup 3+} in GSGG host are similar to those in YSGG host crystals, and the crystal-field interaction of GSGG is weaker than that of YSGG, which may result in the better laser characterization of Er{sup 3+}:GSGG crystal. - Highlights: • The efficient diode-end-pumped laser crystal Er:GSGG has been grown successfully. • The absorption spectra of Er:GSGG have been measured in range of 350–1700 nm. • The fitting result is very well for the root mean square deviation is 9.86 cm{sup −1}. • The 124 levels of Er:GSGG have been assigned from the crystal-field calculations.

Effects of n-3 polyunsaturated fatty acids on cardiac ion channels

Directory of Open Access Journals (Sweden)

Cristina eMoreno

2012-07-01

Full Text Available Dietary n-3 polyunsaturated fatty acids (PUFAs have been reported to exhibit antiarrhythmic properties, attributed to their capability to modulate ion channels. In the present review, we will focus on the effects of PUFAs on cardiac sodium channel (Nav1.5 and two potassium channels (Kv (Kv1.5 and Kv11.1. n-3 marine (docohexaenoic and eicohexapentaenoic acid and plant origin (alpha-linolenic acid PUFAs block Kv1.5 and Kv11.1 channels at physiological concentrations. Also, DHA and EPA decreased Nav1.5 and calcium channels. These effects on Na and Ca channels theoretically should shorten the cardiac APD, whereas the blocking actions of n-3 PUFAs of Kv channels should lengthen the cardiac action potential. Experiments performed in female rabbits fed with a diet rich in n-3 PUFAs show a longer cardiac action potential and effective refractory period. This study was performed to analyze if their antiarrhythmic effects are due to a reduction of triangulation, reverse use-dependence, instability and dispersion of the cardiac action potential (TRIaD as a measure of proarrhythmic effects. Dietary n-3 PUFAs supplementation markedly reduced dofetilide-induced TRIaD and abolished dofetilide-induced torsades de pointes (TdP. Ultrafast sodium channel block by DHA may account for the antiarrhythmic protection of dietary supplements of n-3 PUFAs against dofetilide induced proarrhythmia observed in this animal model. The cardiac effects of n-3 PUFAs resemble those of amiodarone: both block sodium, calcium and potassium channels, have anti-adrenergic properties, can prolong the cardiac action potential, reverse TRIaD and suppress TdP. The main difference is that sodium channel block by n-3 PUFAs has a much faster onset and offset kinetics. Therefore, the electrophysiological profile of n-3 PUFAs appears more desirable: the duration of reduced sodium current (facilitates re-entry is much shorter. The n-3 PUFAs appear as a safer alternative to other antiarrhythmic

Enhanced Power Conversion Efficiency of Perovskite Solar Cells with an Up-Conversion Material of Er3+-Yb3+-Li+ Tri-doped TiO2.

Science.gov (United States)

Zhang, Zhenlong; Qin, Jianqiang; Shi, Wenjia; Liu, Yanyan; Zhang, Yan; Liu, Yuefeng; Gao, Huiping; Mao, Yanli

2018-05-11

In this paper, Er 3+ -Yb 3+ -Li + tri-doped TiO 2 (UC-TiO 2 ) was prepared by an addition of Li + to Er 3+ -Yb 3+ co-doped TiO 2 . The UC-TiO 2 presented an enhanced up-conversion emission compared with Er 3+ -Yb 3+ co-doped TiO 2 . The UC-TiO 2 was applied to the perovskite solar cells. The power conversion efficiency (PCE) of the solar cells without UC-TiO 2 was 14.0%, while the PCE of the solar cells with UC-TiO 2 was increased to 16.5%, which presented an increase of 19%. The results suggested that UC-TiO 2 is an effective up-conversion material. And this study provided a route to expand the spectral absorption of perovskite solar cells from visible light to near-infrared using up-conversion materials.

Long afterglow property of Er{sup 3+} doped Ca{sub 2}SnO{sub 4} phosphor

Energy Technology Data Exchange (ETDEWEB)

Zhang, Dongyun, E-mail: dyz@sit.edu.cn; Shi, Mingming; Sun, Yiwen; Guo, Yunyun; Chang, Chengkang

2016-05-15

A novel green emitting long afterglow phosphor, Er{sup 3+} -doped Ca{sub 2}SnO{sub 4} (Ca{sub 2}SnO{sub 4}:Er{sup 3+}), was prepared successfully via a traditional high temperature solid–state reaction method. Its properties have been characterized and analyzed by utilizing x-ray diffraction (XRD), photoluminescence spectroscope (PLS), afterglow decay curve (ADC) and thermal luminescence spectroscope (TLS). Three main emission peaks of PLS locate at 524, 550 and 668 nm, corresponding to CIE chromaticity coordinates of x = 0.326, y = 0.6592. An optimal doping concentration of Er{sup 3+} of 2% was determined. The Ca{sub 2}SnO{sub 4}:Er{sup 3+} phosphors showed a typical triple-exponential afterglow decay behavior when the UV source was switched off. Thermal simulated luminescence study indicated that the persistent afterglow of Ca{sub 2}SnO{sub 4}:2 mol% Er{sup 3+} phosphors was generated by the suitable electron or hole traps which were resulted from the doping the Ca{sub 2}SnO{sub 4} host with rare-earth ions (Er{sup 3+}). - Highlights: • A novel green emitting long afterglow phosphor, Ca{sub 2}SnO{sub 4}:Er{sup 3+}, was prepared. • An optimal doping concentration of Er{sup 3+} of 2% was determined. • After the UV source was turned off, the Ca{sub 2}SnO{sub 4}:Er{sup 3+} showed a typical triple-exponential afterglow decay behavior. • CIE chromaticity coordinates results confirmed a green light emitting of the Ca{sub 2}SnO{sub 4}:Er{sup 3+}. • The persistent afterglow of the Ca{sub 2}SnO{sub 4}:Er{sup 3+} was attributed to suitable electron or hole traps.

The concentration effect of upconversion luminescence properties in Er3+/Yb3+-codoped Y2(MoO4)3 phosphors

International Nuclear Information System (INIS)

Lu Weili; Cheng Lihong; Sun Jiashi; Zhong Haiyang; Li Xiangping; Tian Yue; Wan Jing; Zheng Yanfeng; Huang Libo; Yu Tingting; Yu Hongquan; Chen Baojiu

2010-01-01

Y 2 (MoO 4 ) 3 :Er 3+ /Yb 3+ phosphors with fixed (varied) Er 3+ and varied (fixed) Yb 3+ concentrations were synthesized by a conventional solid-state reaction. The crystal structure of the phosphors was characterized by means of X-ray diffraction (XRD). Upon 980 nm excitation, very weak blue emission, and strong green and red upconversion emissions centered at 485, 525, 545 and 656 nm were observed. The two-photon process was confirmed to be responsible for both the green and red upconversion emissions. The effects of green upconversion emission intensity ratio ( 2 H 11/2 → 4 I 15/2 versus 4 S 3/2 → 4 I 15/2 ) and the integrated upconversion emission intensity on the Yb 3+ and Er 3+ concentrations were studied.

Management of a Complex Open Channel Network During Flood Events

Science.gov (United States)

Franchini, M.; Valiani, A.; Schippa, L.; Mascellani, G.

2003-04-01

Most part of the area around Ferrara (Italy) is below the mean sea level and an extensive drainage system combined with several pump stations allows the use of this area for both urban development and industrial and agricultural activities. The three main channels of this hydraulic system constitute the Ferrara Inland Waterway (total length approximately 70 km), which connects the Po river near Ferrara to the sea. Because of the level difference between the upstream and dowstream ends of the waterway, three locks are located along it, each of them combined with a set of gates to control the water levels. During rainfall events, most of the water of the basin flows into the waterway and heavy precipitations sometimes cause flooding in several areas. This is due to the insufficiency of the channel network dimensions and an inadequate manual operation of the gates. This study presents a hydrological-hydraulic model for the entire Ferrara basin and a system of rules in order to operate the gates. In particular, their opening is designed to be regulated in real time by monitoring the water level in several sections along the channels. Besides flood peak attenuation, this operation strategy contributes also to the maintenance of a constant water level for irrigation and fluvial navigation during the dry periods. With reference to the flood event of May 1996, it is shown that this floodgate operation policy, unlike that which was actually adopted during that event, would lead to a significant flood peak attenuation, avoiding flooding in the area upstream of Ferrara.

Entrance- and exit-channel effects and the suppression of neutron emission from 64Ni+92Zr→/sup 156/Er/sup */

International Nuclear Information System (INIS)

Love, D.J.G.; Bishop, P.J.; Kirwan, A.; Nolan, P.J.; Thornley, D.J.; Nelson, A.H.; Twin, P.J.

1986-01-01

High--angular-momentum components have been found in the cross section for /sup 64/Ni+/sup 92/Zr→/sup 156/Er /sup */ by γ-ray spectroscopy. They are expected to influence the known low evaporation-neutron multiplicity. The feeding pattern rules out significant trapping in superdeformed states at low spin, an explanation previously advanced. Simple coupled-channels calculations are consistent with the observations. The statistical model with high-l fusion enhanced consistently with observation reproduces the neutron multiplicity satisfactorily

Fluoxetine-induced inhibition of synaptosomal [3H]5-HT release: Possible Ca2+-channel inhibition

International Nuclear Information System (INIS)

Stauderman, K.A.; Gandhi, V.C.; Jones, D.J.

1992-01-01

Fluoxetine, a selective 5-Ht uptake inhibitor, inhibited 15 mM K + -induced [ 3 H]5-HT release from rat spinal cord and cortical synaptosomes at concentrations > 0.5 uM. This effect reflected a property shared by another selective 5-HT uptake inhibitor paroxetine but not by less selective uptake inhibitors such as amitriptyline, desipramine, imipramine or nortriptyline. Inhibition of release by fluoxetine was inversely related to both the concentration of K + used to depolarize the synaptosomes and the concentration of external Ca 2+ . Experiments aimed at determining a mechanism of action revealed that fluoxetine did not inhibit voltage-independent release of [ 3 H]5-HT release induced by the Ca 2+ -ionophore A 23187 or Ca 2+ -independent release induced by fenfluramine. Moreover the 5-HT autoreceptor antagonist methiothepin did not reverse the inhibitory actions of fluoxetine on K + -induced release. Further studies examined the effects of fluoxetine on voltage-dependent Ca 2+ channels and Ca 2+ entry

Preparation and dielectric properties of Dy, Er-doped BaZr0.2Ti0.8O3 ceramics

International Nuclear Information System (INIS)

Hao Sue; Sun Liang; Huang Jinxiang

2008-01-01

Ba(Zr x Ti 1-x )O 3 nanopowders and ceramics with different Zr/Ti ratios of 1:9; 2:8; 2.5:7.5; 3.5:6.5 and 4:6 (x = 0.1, 0.2, 0.25, 0.35, 0.4) have been prepared by sol-gel technology using inorganic zirconium as raw materials, and Zr/Ti ratio of 2:8 is determined as the best one according to the measurements of dielectric properties. So the modified Ba(Zr 0.2 ,Ti 0.8 )O 3 ceramics doped by Dy and Er (the additive content is 0.10%, 0.15%, 0.20%, 0.30% and 0.50% molar ratio, respectively) have been prepared, and the effects of rare earth on the microstructure and dielectric properties of Ba(Zr 0.2 ,Ti 0.8 )O 3 ceramics have been studied. The experimental results show that the effect of Er is better than that of Dy in improving the dielectric properties of BaZr 0.2 Ti 0.8 O 3 ceramics. When the content of Er is 0.15 mol%, the dielectric constant is the highest of 12767, while the dielectric loss is lowered to 0.011; the frequency stabilities and the temperature dependence are also better, which is suitable for application in condenser field

Effects of alkali ions on thermal stability and spectroscopic properties of Er{sup 3+}-doped gallogermanate glasses

Energy Technology Data Exchange (ETDEWEB)

Shi, D.M.; Zhao, Y.G.; Wang, X.F.; Liao, G.H. [Department of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023 (China); Zhao, C. [Department of Physics, South China University of Technology, Guangzhou 510641 (China); MOE Key Lab of Specially Functional Materials and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China); Peng, M.Y. [MOE Key Lab of Specially Functional Materials and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China); Zhang, Q.Y., E-mail: qyzhang@scut.edu.c [MOE Key Lab of Specially Functional Materials and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China)

2011-02-01

Since information transportation capacity of optical communication network increases rapidly, new optical materials are always demanded with gain bandwidth desirably much broader than traditional erbium-doped silica fiber amplifier (EDFA). We show here in this paper the erbium-doped gallogermanate glasses with a full-width at half-maximum (FWHM) more than 50 nm. Incorporation of alkali ions such as Li{sup +}, Na{sup +}, K{sup +} into the system can on the one hand improve the thermal stability of the glasses, and on the other hand enhance the emission at 1.5 {mu}m due to the {sup 4}I{sub 13/2{yields}}{sup 4}I{sub 15/2} transition of Er{sup 3+} and suppress the upconversion process at the same time. This particularly works best for the case of K{sup +} inclusion. This work might give a general idea on controlling the Er{sup 3+} luminescence by simply adjusting the glass component and find a potential laser glass applicable to developing new broadband fiber amplifier. -- Research highlights: {yields} We report on spectroscopic properties of Er{sup 3+}-doped Ga{sub 2}O{sub 3}-GeO{sub 2}-R{sub 2}O (GGR, R=Li, Na and K) glasses for 1.53 {mu}m fiber amplifier. Effects of alkali metal ions on the thermal stability and spectroscopic properties of Er{sup 3+}-doped GGR glasses have been investigated. {yields} Incorporation of alkali ions such as Li{sup +}, Na{sup +}, K{sup +} into the system can on the one hand improve the thermal stability of the glasses, and on the other hand enhance the emission at 1.5 {mu}m due to the {sup 4}I{sub 13/2{yields}}{sup 4}I{sub 15/2} transition of Er{sup 3+} and suppress the upconversion process at the same time. This particularly works best for the case of K{sup +} inclusion. This work might give a general idea on controlling the Er{sup 3+} luminescence by simply adjusting the glass component and find a potential laser glass applicable to developing new broadband fiber amplifier.

Er2O3 coating development and improvisation by metal oxide decomposition method

International Nuclear Information System (INIS)

Rayjada, Pratipalsinh A.; Sircar, Amit; Raole, Prakash M.; Rahman, Raseel; Manocha, Lalit M.

2015-01-01

Compact, highly resistive and chemically as well as physically stable ceramic coatings are going to play vital role in successful and safe exploitation of tritium breeding and recovery system in the future fusion reactors. Due to its stability and high resistivity, Er 2 O 3 was initially studied for resistive coating application to mitigate Magneto Hydro Dynamic (MHD) forces in liquid Li cooled blanket concept. Subsequently, its excellence as tritium permeation barrier (TPB) was also revealed. Ever since, there is a continual thrust on studying its relevant properties and application methods among the fusion technology and materials community. Metal Oxide Decomposition is a chemical method of coating development. One of the major advantages of this process over most of the others is its simplicity and ability to coat complex structures swiftly. The component is dipped into a liquid solution of the Er 2 O 3 and subsequently withdrawn at an optimized constant speed, so as to leave a uniform wet layer on the surface. This can be repeated multiple times after drying the surface to obtain the required thickness. Subsequently, the component is heat treated to obtain crystalline uniform Er 2 O 3 coating over it. However, the porosity of the coatings and substrate oxidation are the challenges for in MOD method. We successfully develop Er 2 O 3 coating in cubic crystalline phase on P91 steel and fused silica substrates using 3 wt% erbium carboxylic acid solution in a solvent containing 50.5 wt% turpentine, 25.5 wt% n-butyl acetate, 8.4 wt% ethyl acetate, a stabilizer, and a viscosity adjustor. A dip coating system equipped with 800 C quartz tube furnace was used to prepare these coatings. The withdrawal speed was chosen as 72 mm/min from the literature survey. The crystallization and microstructure are studied as functions of heat treatment temperature in the range of 500-700 C. We also try to improvise the uniform coverage and porosity of the coating by altering the

Exercise-Induced Rhabdomyolysis and Stress-Induced Malignant Hyperthermia Events, Association with Malignant Hyperthermia Susceptibility, and RYR1 Gene Sequence Variations

Directory of Open Access Journals (Sweden)

Antonella Carsana

2013-01-01

Full Text Available Exertional rhabdomyolysis (ER and stress-induced malignant hyperthermia (MH events are syndromes that primarily afflict military recruits in basic training and athletes. Events similar to those occurring in ER and in stress-induced MH events are triggered after exposure to anesthetic agents in MH-susceptible (MHS patients. MH is an autosomal dominant hypermetabolic condition that occurs in genetically predisposed subjects during general anesthesia, induced by commonly used volatile anesthetics and/or the neuromuscular blocking agent succinylcholine. Triggering agents cause an altered intracellular calcium regulation. Mutations in RYR1 gene have been found in about 70% of MH families. The RYR1 gene encodes the skeletal muscle calcium release channel of the sarcoplasmic reticulum, commonly known as ryanodine receptor type 1 (RYR1. The present work reviews the documented cases of ER or of stress-induced MH events in which RYR1 sequence variations, associated or possibly associated to MHS status, have been identified.

Hepatitis E virus ORF3 is a functional ion channel required for release of infectious particles.

Science.gov (United States)

Ding, Qiang; Heller, Brigitte; Capuccino, Juan M V; Song, Bokai; Nimgaonkar, Ila; Hrebikova, Gabriela; Contreras, Jorge E; Ploss, Alexander

2017-01-31

Hepatitis E virus (HEV) is the leading cause of enterically transmitted viral hepatitis globally. Of HEV's three ORFs, the function of ORF3 has remained elusive. Here, we demonstrate that via homophilic interactions ORF3 forms multimeric complexes associated with intracellular endoplasmic reticulum (ER)-derived membranes. HEV ORF3 shares several structural features with class I viroporins, and the function of HEV ORF3 can be maintained by replacing it with the well-characterized viroporin influenza A virus (IAV) matrix-2 protein. ORF3's ion channel function is further evidenced by its ability to mediate ionic currents when expressed in Xenopus laevis oocytes. Furthermore, we identified several positions in ORF3 critical for its formation of multimeric complexes, ion channel activity, and, ultimately, release of infectious particles. Collectively, our data demonstrate a previously undescribed function of HEV ORF3 as a viroporin, which may serve as an attractive target in developing direct-acting antivirals.

Luminescence investigation of Yb3+/Er3+ codoped single LiYF4 microparticle

International Nuclear Information System (INIS)

Gao, Wei; Zheng, Hairong; He, Enjie; Lu, Ying; Gao, Fangqi

2014-01-01

Tetragonal phase LiYF 4 :Yb 3+ /Er 3+ microparticles are synthesized via facile hydrothermal method. Single LiYF 4 microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. It is found that single LiYF 4 :Yb 3+ /Er 3+ microparticle with sub-structure presents stronger upconversion luminescence emission and smaller intensity ratio of red to green emission than that from LiYF 4 :Yb 3+ /Er 3+ microparticle with no sub-structure. The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion luminescence emission are investigated. The current study suggests that the luminescence observation with single micropaticle can effectively avoid the influence of environment and neighbor particles, which is important for investigating the luminescence properties of micro- or nano-crystals and for extending their application. - Highlights: • Single LiYF 4 microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. • Single LiYF 4 microparticle with different morphology exhibits different fluorescence emission intensity and intensity ratio of red to green emission. • The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion emission are investigated

Synthesis, vibrational characteristic and luminescence properties of Er3+in HNH4ErP3O10

Science.gov (United States)

Chékir-Mzali, Jalila; Elgharbi, Sarra; Horchani-Naifer, Karima; Férid, Mokhtar

2017-11-01

Polycrystalline powders of the triphosphate of ammonium hydrogen and erbium NH4ErHP3O10 are grown by flux method. The obtained sample was characterized by X-Ray Diffraction, Infrared and Raman spectroscopies. It was found that this compound is isostructural with NH4BiHP3O10. It crystallizes in the triclinic system, with space group P-1. The spectroscopic properties have been investigated in the UV-Vis and IR region via absorption, excitation, and emission spectra at room temperature. Also, the particle size distribution was investigated and the average crystallite size of HNH4ErP3O10 was 124.08 nm. The optical band gap energy (Eg ≈ 4.24 eV) was calculated from the diffuse reflectance by using the Kubelka-Munk function and Tauc's relation. The time-resolved luminescence of 4F9/2 emission has also been studied. The decay time was shown to be exponential with a pure radiative transition and the lifetime value for the transition 4F9/2 → 4I15/2 is found equal to 15, 4 μs. The effects of the crystal structure, NH4+ and OH groups on the lifetime have been revealed. The CIE chromaticity coordinates reveal that this phosphor can be a promising Yellow-orange emitting material.

Ag2O dependent up-conversion luminescence properties in Tm3+/Er3+/Yb3+ co-doped oxyfluorogermanate glasses

International Nuclear Information System (INIS)

Hu, Yuebo; Qiu, Jianbei; Song, Zhiguo; Zhou, Dacheng

2014-01-01

Up-conversion (UC) luminescence properties of Ag/Tm 3+ /Er 3+ /Yb 3+ co-doped oxyfluorogermanate glasses have been studied to assess the effective role of silver nanoparticles as a sensitizer for Tm 3+ and Er 3+ ions. The X-ray diffraction patterns obtained in this work do not reveal any crystalline phase in the glass. However, the absorption spectra reveal that surface plasmons resonance band of Ag undergoes a distinct split with two maxima and a very broad absorption peak with a background that extends toward the near infrared (NIR) with the increasing of Ag 2 O added concentration. Transmission electron microscope images confirm that silver nanoparticles have been precipitated from matrix glasses and show their distribution, size, and shapes. In addition, changes in UC luminescence intensity of four emission bands 476, 524, 546, and 658 nm corresponding to 1 G 4 → 3 H 6 (Tm 3+ ), ( 2 H 11/2 , 4 S 3/2 ) → 4 I 15/2 (Er 3+ ), and 4 F 9/2 → 4 I 15/2 (Er 3+ ) transitions, respectively, as a function of silver addition to the base composition have been measured under 980 nm excitation. It is confirmed that Ag 2 O added concentration plays an important role in increasing the UC luminescence intensity; however, further increase in Ag 2 O added concentration reduces the intensity

Cooperative upconversion as the gain-limiting factor in Er doped miniature Al2O3 optical waveguide amplifiers

International Nuclear Information System (INIS)

Kik, P.G.; Polman, A.

2003-01-01

Erbium doped Al 2 O 3 waveguide amplifiers were fabricated using two different doping methods, namely Er ion implantation into sputter deposited Al 2 O 3 , and co-sputtering from an Er 2 O 3 /Al 2 O 3 target. Although the Er concentration in both materials is almost identical (0.28 and 0.31 at. %), the amplifiers show a completely different behavior. Upon pumping with 1.48 μm, the co-sputtered waveguide shows a strong green luminescence from the 4 S 3/2 level, indicating efficient cooperative upconversion in this material. This is confirmed by pump power dependent measurements of the optical transmission at 1.53 μm and the spontaneous emission at 1.53 and 0.98 μm. All measurements can be accurately modeled using a set of rate equations that include first order and second order cooperative upconversion. The first order cooperative upconversion coefficient C 24 is found to be 3.5x10 -16 cm 3 s -1 in the co-sputtered material, two orders of magnitude higher than the value obtained in Er implanted Al 2 O 3 of 4.1x10 -18 cm 3 s -1 . It is concluded that the co-sputtering process results in a strongly inhomogeneous atomic scale spatial distribution of the Er ions. As a result, the co-sputtered waveguides do not show optical gain, while the implanted waveguides do

Measurement of the Inclusive and Fiducial Cross-Section of Single Top-Quark $t$-Channel Events in $pp$ Collisions at $\\sqrt{s}$ = 8 TeV

CERN Document Server

The ATLAS collaboration

2014-01-01

This note presents the measurement of a $t$-channel single top-quark production fiducial cross-section in the lepton+jets channel with 20.3 fb$^{-1}$ of 8 TeV data using a neural-network discriminant. Events are selected by requiring exactly two jets, where one of the jets is required to be $b$-tagged. Signal events from $t$-channel single top-quark processes are enhanced using a neural-network discriminant based on final-state observables. The $t$-channel production cross-section in the fiducial region is obtained from a binned maximum-likelihood fit to the neural-network discriminant. A fiducial cross-section quoted within the detector acceptance of $\\sigma_{\\rm fid} = 3.37 \\pm 0.05 \\, (\\mathrm{stat.}) \\pm 0.47 \\, (\\mathrm{syst.}) \\pm 0.09 \\, (\\mathrm{lumi.})~\\text{pb}$ is obtained. The total inclusive $t$-channel cross-section is calculated using the acceptance predicted by various Monte Carlo generators. If the acceptance from the aMC@NLO+Herwig event generator is used, a value of $\\sigma_t = 82.6 \\pm 1.2...

Multifunctional hydroxyapatite/Na(Y/Gd)F4:Yb3+,Er3+ composite fibers for drug delivery and dual modal imaging.

Science.gov (United States)

Liu, Min; Liu, Hui; Sun, Shufen; Li, Xuejiao; Zhou, Yanmin; Hou, Zhiyao; Lin, Jun

2014-02-04

Porous hydroxyapatite (HAp) composite fibers functionalized with up-conversion (UC) luminescent and magnetic Na(Y/Gd)F4:Yb(3+),Er(3+) nanocrystals (NCs) have been fabricated via electrospinning. After transferring hydrophobic oleic acid-capped Na(Y/Gd)F4:Yb(3+),Er(3+) NCs into aqueous solution, these water-dispersible NCs were dispersed into precursor electrospun solution containing CTAB. Na(Y/Gd)F4:Yb(3+),Er(3+)@HAp composite fibers were fabricated by the high temperature treatment of the electrospun Na(Y/Gd)F4:Yb(3+),Er(3+) NCs decorated precursor fibers. The biocompatibility test on MC 3T3-E1 cells using MTT assay shows that the HAp composite fibers have negligible cytotoxity, which reveals the HAp composite fibers could be a drug carrier for drug delivery. Because the contrast brightening is enhanced at increased concentrations of Gd(3+), the HAp composite fibers can serve as T1 magnetic resonance imaging contrast agents. In addition, the composites uptaken by MC 3T3-E1 cells present the UC luminescent emission of Er(3+) under the excitation of a 980 nm near-infrared laser. The above findings reveal Na(Y/Gd)F4:Yb(3+),Er(3+)@HAp composite fibers have potential applications in drug storage/release and magnetic resonance/UC luminescence imaging.

Suppression effect of silicon (Si) on Er{sup 3+} 1.54μm excitation in ZnO thin films

Energy Technology Data Exchange (ETDEWEB)

Xu, Bo; Lu, Fei, E-mail: lufei@sdu.edu.cn; Fan, Ranran [School of Information Science and Engineering, Shandong University, Jinan, Shandong 250100 (China); Ma, Changdong [Department of Radiation Oncology, Qilu Hospital, Shandong University, Jinan, Shandong 250100 (China)

2016-08-15

We have investigated the photoluminescence (PL) characteristics of ZnO:Er thin films on Si (100) single crystal and SiO{sub 2}-on-silicon (SiO{sub 2}) substrates, synthesized by radio frequency magnetron sputtering. Rutherford backscattering/channeling spectrometry (RBS), X-ray diffraction (XRD) and atomic force microscope (AFM) were used to analyze the properties of thin films. The diffusion depth profiles of Si were determined by second ion mass spectrometry (SIMS). Infrared spectra were obtained from the spectrometer and related instruments. Compared with the results at room temperature (RT), PL (1.54μm) intensity increased when samples were annealed at 250°C and decreased when at 550°C. A new peak at 1.15μm from silicon (Si) appeared in 550°C samples. The Si dopants in ZnO film, either through the diffusion of Si from the substrate or ambient, directly absorbed the energy of pumping light and resulted in the suppression of Er{sup 3+} 1.54μm excitation. Furthermore, the energy transmission efficiency between Si and Er{sup 3+} was very low when compared with silicon nanocrystal (Si-NC). Both made the PL (1.54μm) intensity decrease. All the data in experiments proved the negative effects of Si dopants on PL at 1.54μm. And further research is going on.

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.)

Ion-irradiation-induced phase transformation in rare earth sesquioxides (Dy2O3,Er2O3,Lu2O3)

International Nuclear Information System (INIS)

Tang, M.; Lu, P.; Valdez, J.A.; Sickafus, K.E.

2006-01-01

Polycrystalline pellets of cubic C-type rare earth structure (Ia3) Dy 2 O 3 , Er 2 O 3 , and Lu 2 O 3 were irradiated at cryogenic temperature (120 K) with 300 keV Kr ++ ions to a maximum fluence of 1x10 20 Kr/m 2 . Irradiated specimens were examined using grazing incidence x-ray diffraction and transmission electron microscopy. Ion irradiation leads to different radiation effects in these three materials. First, Dy 2 O 3 begins to transform to a monoclinic B-type rare earth structure (C2/m) at a peak dose of ∼5 displacements per atom (dpa) (corresponding to a fluence of 2x10 19 Kr/m 2 ). This transformation is nearly complete at a peak dose of 25 dpa (a fluence of 1x10 20 Kr/m 2 ). Er 2 O 3 also transforms to the B-type structure, but the transformation starts at a higher irradiation dose of about 15-20 dpa [a fluence of about (6-8)x10 19 Kr/m 2 ]. Lu 2 O 3 was found to maintain the C-type structure even at the highest irradiation dose of 25 dpa (a fluence of 1x10 20 Kr/m 2 ). No C-to-B transformation was observed in Lu 2 O 3 . The irradiation dose dependence of the C-to-B phase transformation observed in Dy 2 O 3 , Er 2 O 3 , and Lu 2 O 3 is closely related to the temperature dependence of the C-to-B phase transformation found in phase diagrams for these three materials

em cristais de Ho:YLF e Er:YLF na região de 3m

Directory of Open Access Journals (Sweden)

Fábio Henrique Jagosich

2006-01-01

Full Text Available In this work, the deactivation energy transfer mechanisms of 4I13/2 of Er3+ and 5I7 of Ho3+ levels in crystals of LiYF4 (YLF co-doped with Nd3+, Tb3+ and Eu3+ are studied. It was determined the best combination with deactivator ions, capable to maximize the laser gain in the middle of the Ho3+ in 2.9 micrometers (mm and the Er3+ in 2.75 mm operation. The results showed that the Tb3+ and Eu3+ are the best deactivators to the Ho3+ laser operation, while for the Ho3+ laser operation, the best ion deactivator is the Nd3+. The energy transfer characterizations were carried out using the Förster-Dexter method, which consists in the determination of the interaction critic ray, to start from the integral superposition of the absorption cross section spectrum and the involved ions emission.

Synthesis of Er(III)/Yb(III)-doped BiF3 upconversion nanoparticles for use in optical thermometry.

Science.gov (United States)

Du, Peng; Yu, Jae Su

2018-03-23

The authors describe an ethylene glycol assisted precipitation method for synthesis of Er(III)/Yb(III)-doped BiF 3 nanoparticles (NPs) at room temperature. Under 980-nm light irradiation, the NPs emit upconversion (UC) emission of Er(III) ions as a result of a two-photon absorption process. The temperature-dependent green emissions (peaking at 525 and 545 nm) are used to establish an unambiguous relationship between the ratio of fluorescence intensities and temperature. The NPs have a maximum sensitivity of 6.5 × 10 -3  K -1 at 619 K and can be applied over the 291-691 K temperature range. The results indicate that these NPs are a promising candidate for optical thermometry. Graphical abstract Schematic of the room-temperature preparation of Er(III)/Yb(III)-doped BiF 3 nanoparticles with strongly temperature-dependent upconversion emission.

Large rotating field entropy change in ErFeO3 single crystal with angular distribution contribution

Science.gov (United States)

Huang, Ruoxiang; Cao, Shixun; Ren, Wei; Zhan, Sheng; Kang, Baojuan; Zhang, Jincang

2013-10-01

We report the rotating field entropy of ErFeO3 single-crystal in a temperature range of 3-40 K. The giant magnetic entropy change, ΔSM = -20.7 J/(kg K), and the refrigerant capacity, RC = 273.5 J/kg, are observed near T =6 K. The anisotropic constants at 6 K, K1 = 1.24× 103 J/kg, K2 = 0.74 × 103 J/kg, in the bc plane are obtained. By considering the magnetocrystalline anisotropy and Fermi-Dirac angular distribution along the orientation of spontaneous magnetization, the experimental results can be well simulated. Our present work demonstrates that ErFeO3 crystal may find practical use for low temperature anisotropic magnetic refrigeration.

Spectroscopy and visible frequency upconversion in Er3+-Yb3+: TeO2-ZnO glass.

Science.gov (United States)

Mohanty, Deepak Kumar; Rai, Vineet Kumar

2014-01-01

The UV-Vis-NIR absorption studies of the Er(3+)/Er(3+)-Yb(3+) doped/codoped TeO2-ZnO (TZO) glasses fabricated by the melting and quenching method has been performed. The spectroscopic radiative parameters viz. radiative transition probabilities, branching ratios and lifetimes have been determined from the absorption spectrum by using Judd-Ofelt theory. The near infrared (NIR) to visible frequency upconversion (UC) have been monitored by using an excitation of 976 nm wavelength radiation from a CW diode laser. The effect of codoping with Yb(3+) ions on the intensity of the UC emission bands from the Er(3+) ions throughout visible region has been studied. The mechanism responsible for the observed upconversion emissions in the prepared samples have been explained on the basis of excited state absorption and efficient energy transfer processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Die HECT-Ligase Hul5, eine neue Komponente der ER-assoziierten Proteindegradation

OpenAIRE

Kohlmann, Sonja

2007-01-01

Die meisten sekretorischen Proteine der eukaryontischen Zellen erreichen durch das endoplasmatische Retikulum (ER) den sekretorischen Signalweg. Sie gelangen vom Zytoplasma durch einen Kanal in der ER-Membran in das ER, wo sie ihre native Konformation erhalten. Das ER enthält ein strenges Qualitätskontrollsystem, welches fehlgefaltete Proteine erkennt, im ER zurückhält und letztendlich der ER-assoziierten Degradation (ERAD) zuführt. Die ER-Qualitätskontrolle und die ER-assoziierte Degradation...

Effect of Er3+ doping on structural, morphological and photocatalytical properties of ZnO thin films

Science.gov (United States)

Bouhouche, S.; Bensouici, F.; Toubane, M.; Azizi, A.; Otmani, A.; Chebout, K.; Kezzoula, F.; Tala-Ighil, R.; Bououdina, M.

2018-05-01

In this research work, structure, microstructure, optical and photocatalytic properties of undoped and Erbium doped nanostructured ZnO thin films prepared by sol-gel dip-coating are investigated. X-ray diffraction (XRD) analysis indicates that the deposited films crystallize within the hexagonal wurtzite-type structure with a preferential growth orientation along (002) plane. Morphological observations using scanning electron microscopy (SEM) reveal important influence of Er concentration; displaying homogeneous and dense aspect for undoped to 0.3% then grid-like morphology for 0.4 and 0.5%. UV/vis/NIR transmittance spectroscopy spectra display a transmittance over 70%, and small variation in the energy gap energy 3.263–3.278 eV. Wettability test of ZnO thin films surface ranges from hydrophilic aspect for pure ZnO to hydrophobic one for Er doped ZnO, and the contact angle is found to increase from 58.7° for pure ZnO up to 98.4° for 0.4% Er doped ZnO. The photocatalytic activity measurements evaluated using the degradation of methylene blue (MB) under UV light irradiation demonstrate that undoped ZnO film shows higher photocatalytic activity compared to Er doped ZnO films, which may be attributed to the deterioration of films’crystallinity resulting in lower transmittance.

Fluorescence properties of Yb3+-Er3+ co-doped phosphate glasses containing silver nanoparticles

Science.gov (United States)

Martínez Gámez, Ma A.; Vallejo H, Miguel A.; Kiryanov, A. V.; Licea-Jiménez, L.; Lucio M, J. L.; Pérez-García, S. A.

2018-04-01

Er3+-Yb3+ co-doped phosphate glasses containing silver nitrate (SN), were fabricated. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) analyses were used to evidence the nucleation and presence of silver nanoparticles (SNP). The basic parameters of the glasses were inspected by means of absorption and fluorescence spectra, and fluorescence lifetimes under excitation at 916 nm (in-band of Yb3+), and at 406 nm (in-band of surface plasmon resonance given by the presence of SNP). The spectra as well as estimates for the basic parameters defining the lasing/amplifying potential of the glasses were studied as a function of SN concentration. The experimental results indicate that by increasing the SN content an enhancement of Er3+/Yb3+ fluorescence takes place.

Broadened band C-telecom and intense upconversion emission of Er{sup 3+}/Yb{sup 3+} co-doped CaYAlO{sub 4} luminescent material obtained by an easy route

Energy Technology Data Exchange (ETDEWEB)

Perrella, R.V.; Schiavon, M.A. [Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João del Rei (UFSJ), Campus Dom Bosco, Praça Dom Helvécio, 74, 36301-160 São João del Rei, MG (Brazil); Pecoraro, E.; Ribeiro, S.J.L. [UNESP, Institute of Chemistry, P.O. Box 355, 14800-970 Araraquara, SP (Brazil); Ferrari, J.L., E-mail: ferrari@ufsj.edu.br [Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João del Rei (UFSJ), Campus Dom Bosco, Praça Dom Helvécio, 74, 36301-160 São João del Rei, MG (Brazil)

2016-10-15

This work reports on photoluminescence properties of Er{sup 3+}/Yb{sup 3+} co-doped CaYAlO{sub 4} in powder form, synthesized by an easy route using citric acid as ligand to form complex precursor. The 1.2 mol% of Yb{sup 3+} was fixed, while the amount of Er{sup 3+} changed in 0.5, 1.5 and 3 mol% in order to evaluate the photoluminescence properties as a function of the Er{sup 3+} concentration. The structural and thermal properties of the viscous solutions and powder materials obtained after the heat-treatment at 1000, 1100 and 1200 °C for 4 h were evaluated by XRD, FTIR and TG/DTA analysis. The results showed the formation of pure CaYAlO{sub 4} tetragonal crystalline phase after heat-treatment at 1100 °C and 1200 °C. Intense emission in the visible region under excitation at 980 nm was attributed to upconversion process, from Er{sup 3+} intra-configurational f–f transitions. The emissions were assigned to the transitions {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2} and {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} (green region), and {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} (red region) energy levels. The ratio between emission band integrated areas assigned to the red and green emissions increased as a function of Er{sup 3+} concentration. Under excitation at 980 nm with 100 mW of power pump, the materials also showed intense and broadening emission with maximum at 1520 nm with FWHM of 84.74 nm for the sample CaYAlO{sub 4}:1.5% Er{sup 3+}/1.2% Yb{sup 3+} heat-treated at 1000 °C for 4 h. The photoluminescence properties showed that these materials are promising for use in C-telecom band as optical amplifier biological marker or/and solid-state laser devices under excitation at 980 nm.

Spectroscopic study of magnetic phase transitions and magnetic structures in rare earth ferroborates RFe3(BO3)4 (R = Y, Er, Tb, Gd)

International Nuclear Information System (INIS)

Popova, M.N.; Chukalina, E.P.; Stanislavchuk, T.N.; Bezmaternykh, L.N.

2006-01-01

One investigated into the absorption spectra of RFe 3 (BO 3 ) 4 , R=Y, Er, Tb, Gd rare earth borate single crystals containing erbium (1%) introduced to serve as a probe. On the basis of the temperature dependences of Er 3+ ion spectral line splittings one determined the values of the magnetic ordering temperatures of Er, Tb and Gd ferroborates and the temperatures of the spin reoriented first order phase transition in GdFe 3 (BO 3 ) 4 :Er 3+ (1%). On the basis of comparison of the splitting values of Er 3+ ion ground state in RFe 3 (BO 3 ) 4 (R=Y, Er, Tb) and in GdFe 3 (BO 3 )4 compounds the magnetic structure of which is known one makes a concussion about the orientation of iron magnetic moments in the magneto-ordered state: a lightly planar structure is observed for YFe 3 (BO 3 ) 4 and ErFe 3 (BO 3 ) 4 and a lightly axial one - for TbFe 3 (BO 3 ) 4 . One discusses the role of R 3+ ion single ion anisotropy when determining the magnetic structure type in RFe 3 (BO 3 ) 4 [ru

Colossal elastoresistance, electroresistance and magnetoresistance in Pr0.5Sr0.5MnO3 thin films

International Nuclear Information System (INIS)

Chen, Liping; Guo, Xuexiang; Gao, J.

2016-01-01

Pr 0.5 Sr 0.5 MnO 3 thin films on substrates of (001)-oriented LaAlO 3 were epitaxially grown by pulsed laser deposition. It was found that a substrate-induced strain of ~1.3% brings a great resistivity change of ~98% at 25 K. We studied the dependence of resistivity on the applied electric current and magnetic field. In the greatly strained films of 60 nm thickness the electroresistance ER=[ρ(I 1 μA )−ρ(I 1000 μA )]/ρ(I 1 μA ) reaches ~70% at T=25 K, much higher than ER~7% in the strain-relaxed films of 400 nm thickness, implying the strain effect on ER. Also the magnetoresistance of the film falls with strain-relaxation. Therefore the electric properties of the film could be efficiently modified by strain, electric current and magnetic field. All of them may be explained by the effect on the percolative phase separation and competition in the half-doped manganite material. The manganite films located at phase boundary are expected to be an ideal compound for providing practical colossal effects of elastoresistance, electroresistance and magnetoresistance due to the multiphase coexistence. - Highlights: • The electric current-induced electroresistance (ER) and magnetoresistance (MR)studies on PLD grown Pr 0.5 Sr 0.5 MnO 3 /(001) LaAlO 3 films were found to be greatly sensitive to the film thickness arising from the strain. • It is shown that, 60 nm film exhibit compressive in-plane strain which leads to phase separation and hence colossal MR and ER. • Our results suggest that the manganites located at phase boundary may be an ideal compound for providing practical colossal effects of elastoresistance, electroresistance and magnetoresistance.

Thermal expansion of phosphates with the NaZr2(PO4)3 structure containing lanthanides and zirconium: R0.33Zr2(PO4)3 (R = Nd, Eu, Er) and Er0.33(1–x) Zr0.25xZr2(PO4)3

International Nuclear Information System (INIS)

Volgutov, V. Yu.; Orlova, A. I.

2015-01-01

Phosphates R 0.33 Zr 2 (PO 4 ) 3 (R = Nd, Eu, or Er) and Er 0.33(1–x) Zr 0.25 Zr 2 (PO 4 ) 3 (x = 0, 0.25, 0.5, 0.75, 1.0) of the NaZr 2 (PO 4 ) 3 family have been synthesized and investigated by high-temperature X-ray diffraction. The crystallochemical approach is used to obtain compounds with expected small and controllable thermal-expansion parameters. Phosphates with close-to-zero thermal-expansion parameters, including those with low thermal-expansion anisotropy, have been obtained: Nd 0.33 Zr 2 (PO 4 ) 3 with α a =–2.21 × 10 −6 °C −1 , α c = 0.81 × 10 −6 °C −1 , and Δα = 3.02 × 10 −6 °C –1 and Er 0.08 Zr 0.19 Zr 2 (PO 4 ) 3 with α a =–1.86 × 10 −6 °C −1 , α c = 1.73 × 10 −6 °C −1 , and Δα = 3.58 × 10 −6 °C −1

Vibronic intensities for Er3+ in Cs2 NaErCl6

International Nuclear Information System (INIS)

Acevedo, R.; Navarro, G.; Meruane, T.

2001-01-01

In this current study, we have undertaken vibronic intensity calculations for the absorptions (( 4 I 15/2 ) Γ k ) → (( 4 I 13/2 ) Γ l ) of the Er 3+ in the Cs 2 NaErCl 6 elpasolite type system. This system is extremely complicated to handle from both a theoretical and an experimental viewpoints. This theoretical work shows that over an energy range of about 400 cm -1 , a substantial amount of transitions are likely to take place (about 100 transitions; twenty five of them are magnetic dipole allowed and seventy five are vibronically allowed). It is then a formidable task to identify and assign all of these transitions in a non-ambiguous way. Also the experimental evidence available for these absorptions is related to a total of about twenty lines in the luminescence spectrum of this system. The spectrum itself is very challenging and the superposition of spectral features is most likely to occur. A careful analysis of the calculated vibronic intensities and overall oscillator strengths for the various transitions indicates that the current model used is both flexible and appropriate to deal with this kind of systems. In a forthcoming paper, we will examine the rather unusual high intensity associated with the (( 4 I 15/2 ) Γ k ) → (( 4 S 3/2 ) Γ l ) excitations. (Author)

Effect of silver nanoparticles on the 1.53 μm fluorescence in Er3+/Yb3+ codoped tellurite glasses

Science.gov (United States)

Wu, Libo; Zhou, Yaxun; Zhou, Zizhong; Cheng, Pan; Huang, Bo; Yang, Fengjing; Li, Jun

2016-07-01

Improving the spectroscopic properties of rare earth (RE) doped glass materials is a challenging task. In the present work the metallic silver nanoparticles (Ag NPs) were embedded into Er3+/Yb3+ codoped tellurite glasses with composition TeO2-Bi2O3-TiO2, prepared using melt-quenching and subsequent heat-treated techniques, and the improved effect of Ag NPs on the 1.53 μm band fluorescence of Er3+ ions was investigated. About 24 h heat-treatment of Er3+/Yb3+ codoped tellurite glass containing 1 mol % amount of AgNO3 at the temperature 370 °C yielded the well-dispersed and near-spherical Ag NPs with ∼11.4 nm average diameter as evidenced by transmission electron microscopy (TEM) image. The intense 1.53 μm band fluorescence was observed in the prepared Er3+/Yb3+ codoped tellurite glasses under the excitation of 980 nm and was further improved with the presence of Ag NPs in the glass matrix, which is attributed to the enhanced local electric field around doped RE ions induced by Ag NPs and the possible energy transfer from Ag NPs to Er3+ ions. The enhanced local electric field was well demonstrated by comparing the variation of emission spectra of hypersensitive probe Eu3+ ions in tellurite glasses with and without Ag NPs. From the Judd-Ofelt analysis, it was also found that the value of Ω6 intensity parameter increased slightly with the increase of Ag NPs concentration in a certain range, also confirming the possibility of realizing strong fluorescence emission. In addition, the amorphous structural nature was demonstrated by the measured X-ray diffraction (XRD) patterns with no sharp diffraction peak. The enhanced 1.53 μm band fluorescence indicates that the Er3+/Yb3+ codoped tellurite glass with an appropriate amount of Ag NPs is a promising candidate for the development of Er3+-doped fiber amplifiers (EDFAs) applied in the WDM systems.

Structural and spectroscopic studies on Er3+ doped boro-tellurite glasses

Science.gov (United States)

Selvaraju, K.; Marimuthu, K.

2012-04-01

Er3+ doped boro-tellurite glasses with the chemical composition (69-x)B2O3-xTeO2-15MgO-15K2O-1Er2O3 (where x=0, 10, 20, 30 and 40 wt%) have been prepared and their structural and spectroscopic behavior were studied and reported. The varying tellurium dioxide content in the host matrix that results, changes in structural and spectroscopic behavior around Er3+ ions are explored through XRD, FTIR, UV-VIS-NIR and luminescence measurements. The XRD pattern confirms the amorphous nature of the prepared glasses and the FTIR spectra explore the fundamental groups and the local structural units in the prepared boro-tellurite glasses. The bonding parameters (βbar and δ) have been calculated from the observed band positions of the absorption spectra to claim the ionic/covalent nature of the prepared glasses. The Judd-Ofelt (JO) intensity parameters Ωλ (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from the absorption spectra and their results are studied and compared with reported literature. The variation in the JO parameters Ωλ (λ=2, 4 and 6) with the change in chemical composition have been discussed in detail. The JO parameters have also been used to derive the important radiative properties like transition probability (A), branching ratio (βR) and peak stimulated emission cross-section (σPE) for the excited state transitions 2H9/2→4I15/2 and 2H11/2 and 4S3/2→4I15/2 of the Er3+ ions and the results were studied and reported. Using Davis and Mott theory, optical band gap energy (Eopt) values for the direct and indirect allowed transitions have been calculated and discussed along with the Urbach energy values for the prepared Er3+ doped boro-tellurite glasses in the present study. The optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar results.

Cryo-electron microscopy structure of the lysosomal calcium-permeable channel TRPML3.

Science.gov (United States)

Hirschi, Marscha; Herzik, Mark A; Wie, Jinhong; Suo, Yang; Borschel, William F; Ren, Dejian; Lander, Gabriel C; Lee, Seok-Yong

2017-10-19

The modulation of ion channel activity by lipids is increasingly recognized as a fundamental component of cellular signalling. The transient receptor potential mucolipin (TRPML) channel family belongs to the TRP superfamily and is composed of three members: TRPML1-TRPML3. TRPMLs are the major Ca 2+ -permeable channels on late endosomes and lysosomes (LEL). They regulate the release of Ca 2+ from organelles, which is important for various physiological processes, including organelle trafficking and fusion. Loss-of-function mutations in the MCOLN1 gene, which encodes TRPML1, cause the neurodegenerative lysosomal storage disorder mucolipidosis type IV, and a gain-of-function mutation (Ala419Pro) in TRPML3 gives rise to the varitint-waddler (Va) mouse phenotype. Notably, TRPML channels are activated by the low-abundance and LEL-enriched signalling lipid phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P 2 ), whereas other phosphoinositides such as PtdIns(4,5)P 2 , which is enriched in plasma membranes, inhibit TRPMLs. Conserved basic residues at the N terminus of the channel are important for activation by PtdIns(3,5)P 2 and inhibition by PtdIns(4,5)P 2 . However, owing to a lack of structural information, the mechanism by which TRPML channels recognize PtdIns(3,5)P 2 and increase their Ca 2+ conductance remains unclear. Here we present the cryo-electron microscopy (cryo-EM) structure of a full-length TRPML3 channel from the common marmoset (Callithrix jacchus) at an overall resolution of 2.9 Å. Our structure reveals not only the molecular basis of ion conduction but also the unique architecture of TRPMLs, wherein the voltage sensor-like domain is linked to the pore via a cytosolic domain that we term the mucolipin domain. Combined with functional studies, these data suggest that the mucolipin domain is responsible for PtdIns(3,5)P 2 binding and subsequent channel activation, and that it acts as a 'gating pulley' for lipid-dependent TRPML gating.

Stochastic simulation of a single inositol 1,4,5-trisphosphate-sensitive Ca2+ channel reveals repetitive openings during 'blip-like' Ca2+ transients.

Science.gov (United States)

Swillens, S; Champeil, P; Combettes, L; Dupont, G

1998-05-01

Confocal microscope studies with fluorescent dyes of inositol 1,4,5-trisphosphate (InsP3)-induced intracellular Ca2+ mobilization recently established the existence of 'elementary' events, dependent on the activity of individual InsP3-sensitive Ca2+ channels. In the present work, we try by theoretical stochastic simulation to explain the smallest signals observed in those studies, which were referred to as Ca2+ 'blips' [Parker I., Yao Y. Ca2+ transients associated with openings of inositol trisphosphate-gated channels in Xenopus oocytes. J Physiol Lond 1996; 491: 663-668]. For this purpose, we assumed a simple molecular model for the InsP3-sensitive Ca2+ channel and defined a set of parameter values accounting for the results obtained in electrophysiological bilayer experiments [Bezprozvanny I., Watras J., Ehrlich B.E. Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum. Nature 1991; 351: 751-754; Bezprozvanny I., Ehrlich B.E. Inositol (1,4,5)-trisphosphate (InsP3)-gated Ca channels from cerebellum: conduction properties for divalent cations and regulation by intraluminal calcium. J Gen Physiol 1994; 104: 821-856]. With a stochastic procedure which considered cytosolic Ca2+ diffusion explicitly, we then simulated the behaviour of a single channel, placed in a realistic physiological environment. An attractive result was that the simulated channel exhibited bursts of activity, arising from repetitive channel openings, which were responsible for transient rises in Ca2+ concentration and were reminiscent of the relatively long-duration experimental Ca2+ blips. The influence of the values chosen for the various parameters (affinity and diffusion coefficient of the buffers, luminal Ca2+ concentration) on the kinetic characteristics of these theoretical blips is analyzed.

Optical decoherence and persistent spectral hole burning in Er{sup 3+}:LiNbO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Thiel, C.W., E-mail: thiel@physics.montana.ed [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Macfarlane, R.M. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); IBM Almaden Research Center, San Jose, CA 95120 (United States); Boettger, T. [Department of Physics, University of San Francisco, San Francisco, CA 94117 (United States); Sun, Y. [Department of Physics, University of South Dakota, Vermillion, SD 57069 (United States); Cone, R.L. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

2010-09-15

Developing new resonant optical materials for spatial-spectral holography and quantum information applications requires detailed knowledge of the decoherence and population relaxation dynamics for the quantum states involved in the optical transitions, motivating the need for fundamental material studies. We report recent progress in studying these properties in erbium-doped lithium niobate at liquid helium temperatures. The influence of temperature, applied magnetic fields, measurement timescale, and dopant concentration were probed using photon echo spectroscopy and time-resolved spectral hole burning on the 1532 nm transition of Er{sup 3+}:LiNbO{sub 3}. Effects of spectral diffusion due to interactions between Er{sup 3+} ions and between the Er{sup 3+} ion and {sup 7}Li and {sup 93}Nb nuclear spins in the host lattice were observed. In addition, long-lived persistent spectral storage of seconds to minutes was observed due to non-equilibrium population redistribution among superhyperfine states.

Analysis of Well ER-EC-5 Testing, Western Pahute Mesa-Oasis Valley FY 2000 Testing Program

Energy Technology Data Exchange (ETDEWEB)

None

2002-09-30

This report documents the analysis of the data collected for Well ER-EC-5 during the Western Pahute Mesa - Oasis Valley (WPM-OV) well development and testing program that was conducted during fiscal year (FY) 2000. The data collection for that program is documented in Appendix A, Western Pahute Mesa - Oasis Valley, Well ER-EC-5 Data Report for Development and Hydraulic Testing.

Double NIR laser stimulation and enhancing the thermal sensitivity of Er3+/Tm3+/Nd3+ doped multilayer core-shell nanoparticles.

Science.gov (United States)

Ba, Zhaojing; Hu, Min; Zhao, Yiming; Wang, Yiqing; Wang, Jing; Zhang, Zhenxi

2018-06-04

Non-contact thermal sensors are important devices to study cellular processes and monitor temperature in vivo. Herein, a novel highly sensitive nanothermometer based on NaYF4:Yb,Er@ NaYF4@NaYF4:Yb,Tm@ NaYF4:Nd (denoted as Er@Y@Tm@Nd) was prepared by a facile solvothermal method. When excited by the NIR light of 808 and 980 nm, the as-prepared Er@Y@Tm@Nd nanoparticles could emit both blue and green light respectively, since the lanthanide cations responsible for these emissions are gathered inside this nanostructure. The green and blue light intensity ratio exhibits obvious temperature dependence in the range of the physiological temperature. Additionally, the fluorescence intensity of Er3+ and Tm3+ are also greatly enhanced due to the multilayer structure that implies avoiding the Er3+ and Tm3+ energy cross-relaxation by introduction of a NaYF4 wall between them. The as-prepared core-shell-shell-shell structure with Er3+ and Tm3+ in different layers improves dozens of times of the thermal sensitivity based on the non-thermal coupling levels of the probe: the maximum values for the sensitivity are 2.95% K-1 (IEr-521/ITm-450) and 6.30% K-1 (ITm-474/IEr-541) when excited by 980 and 808 nm laser sources respectively. These values are well above those previously reported (< 0.7% K-1), indicating that the prepared nanostructures are temperature sensors with excellent thermal sensitivity and sensitive to NIR wavelength excitation that makes them highly preferred for thermal detection. © 2018 IOP Publishing Ltd.

Structural phase transformations in KYF4:Er3+ nanoparticles synthesized by hydrothermal method for upconversion applications

Science.gov (United States)

Yamini, S.; Priya, P. Sakthi; Gunaseelan, M.; Senthilselvan, J.

2017-05-01

KYF4:10%Er3+ upconversion nanoparticles was synthesized by hydrothermal method with potassium hydroxides (KOH) as precursor. Prepared samples were calcined at 600 °C using double crucible method. XRD patterns of as prepared KYF4 and KYF4:Er3+ samples confirm the tetragonal structure, which is well matched with the standard data. Surface morphology is recorded for 600 °C calcined samples using High resolution scanning electron microscopy (HRSEM) shows spheroidal shape with particle sizes of ˜80 nm. From UV-Visible and EDX spectroscopy presence of Er3+ in KYF4:10%Er3+ is confirmed. The prepared KYF4:10%Er3+ can be used to improve efficiency of solar cells, display devices and fiber optical telecommunication applications.

Calcium Homeostasis and ER Stress in Control of Autophagy in Cancer Cells

Directory of Open Access Journals (Sweden)

Elżbieta Kania

2015-01-01

Full Text Available Autophagy is a basic catabolic process, serving as an internal engine during responses to various cellular stresses. As regards cancer, autophagy may play a tumor suppressive role by preserving cellular integrity during tumor development and by possible contribution to cell death. However, autophagy may also exert oncogenic effects by promoting tumor cell survival and preventing cell death, for example, upon anticancer treatment. The major factors influencing autophagy are Ca2+ homeostasis perturbation and starvation. Several Ca2+ channels like voltage-gated T- and L-type channels, IP3 receptors, or CRAC are involved in autophagy regulation. Glucose transporters, mainly from GLUT family, which are often upregulated in cancer, are also prominent targets for autophagy induction. Signals from both Ca2+ perturbations and glucose transport blockage might be integrated at UPR and ER stress activation. Molecular pathways such as IRE 1-JNK-Bcl-2, PERK-eIF2α-ATF4, or ATF6-XBP 1-ATG are related to autophagy induced through ER stress. Moreover ER molecular chaperones such as GRP78/BiP and transcription factors like CHOP participate in regulation of ER stress-mediated autophagy. Autophagy modulation might be promising in anticancer therapies; however, it is a context-dependent matter whether inhibition or activation of autophagy leads to tumor cell death.

Development of low-cost open source 3D gel printer "RepRap SWIM-ER"

Science.gov (United States)

Sato, Kei; Basher, Samiul; Ota, Takafumi; Tase, Taishi; Takamatsu, Kyuichiro; Saito, Azusa; Khosla, Ajit; Kawakami, Masaru; Furuawa, Hidemitsu

2017-04-01

Gels are soft and wet materials having low friction, good biocompatibility, and material permeability. It is expected that gel materials will be used as new kinds of industrial materials in the engineering and medical applications. But it cannot build a complicated shape. Soft & Wet Matter Engineering Laboratory developed a 3D gel Printer "SWIM-ER", has enabled modeling of complex shapes of the gel. However, this is expensive. Therefore not all of the gel researchers and the companies have such a device. To solve this problem, we manufacture a low-cost open-source 3D gel printer "RepRap SWIM-ER" from the RepRap. We made the components required to manufacture the "RepRap SWIM-ER" from the 3D printer and chose a light source. In addition, we produced the P-DN gel for RepRap SWIM-ER and conducted the molding test to confirm whether RepRap SWIM-ER can used it.

Potential emerging treatment in vitiligo using Er:YAG in combination with 5FU and clobetasol.

Science.gov (United States)

Mokhtari, Fatemeh; Bostakian, Anis; Shahmoradi, Zabihollah; Jafari-Koshki, Tohid; Iraji, Fariba; Faghihi, Gita; Hosseini, Sayed Mohsen; Bafandeh, Behzad

2018-04-01

Vitiligo is a pigmentary disorder of skin affecting at least 1% of the world population of all races in both sexes. Its importance is mainly due to subsequent social and psychological problems rather than clinical complications. Various treatment choices are available for vitiligo; however, laser-based courses have shown to give more acceptable results. The aim of this trial was to evaluate the efficacy of Er:YAG laser as a supplementary medicine to topical 5FU and clobetasol in vitiligo patients. Two comparable vitiligo patches from 38 eligible patients were randomized to receive topical 5FU and clobetasol in control group and additional Er:YAG laser in intervention group. Major outcomes of interest were the size of patch and pigmentation score at randomization and 2 and 4 months after therapy. Final sample included 18 (47%) male patients and age of 35.66±8.04. The performance Er:YAG group was superior in all sites. Reduction in the size of patches was greater in Er:YAG group (p-value=.004). Also, this group showed a higher pigmentation scores in the trial period than control group (p-value<.001). Greater reduction in the size and increase in pigmentation score was seen in Er:YAG group especially for short periods after therapy and repeating laser sessions may help improving final outcomes. Er:AYG could help in reducing complications of long-term topical treatments, achieving faster response, and improving patient adherence. © 2017 Wiley Periodicals, Inc.

Mesoporous silica-coated NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} particles for drug release

Energy Technology Data Exchange (ETDEWEB)

Kong Deyan; Fan Yong; Zhang Cuimiao; Lin Jun, E-mail: jlin@ciac.jl.c [Chinese Academy of Sciences, State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry (China)

2010-02-15

NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. These NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+} nanoparticles can be coated with mesoporous silica using nonionic triblock copolymer EO{sub 20}PO{sub 70}EO{sub 20} (P 123) as structure-directing agent and other materials. The composites can load ibuprofen and release the drug in the phosphate buffer solution (PBS). The composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen absorption/desorption isotherms, fluorescence spectra, and UV/Vis absorption spectra, respectively. The composites have the mesoporous structure. In addition, the composites emit red fluorescence (from Er{sup 3+}) under 980 nm near infrared laser excitation, which can be used as fluorescent probes in the drug-delivery system.

Near infrared and upconversion luminescence behaviour of Er3+/Yb3+ codoped boro-tellurite glasses

Science.gov (United States)

Maheshvaran, K.; Arunkumar, S.; Vijayakumar, R.; Marimuthu, K.

2014-04-01

The broadband NIR and upconversion luminescence behavior in a new series of Er3+/Yb3+ codoped TeO2-B2O3-SrO-BaO-Li2O-LiF glasses have been studied exciting at a wavelength of 980 nm using semiconductor laser. A broadband emission is observed from 1450 to 1650 nm with a full width at half maximum (FWHM) around 165 nm in 0.5wt% Yb3+ ion content E0.5YLTB glass. The radiative parameters such as transition probability (A), stimulated emission cross-section (σE), experimental and calculated branching ratios (βR), optical gain width (σp×FWHM) and radiative lifetime (τcal) have been calculated for the 4I13/2→4I15/2 NIR emission. Upconversion luminescence spectra of the prepared glasses have been studied and the ESA & ET processes have also been discussed and reported.

Study of upconversion fluorescence property of novel Er3+/Yb3+ co-doped tellurite glasses.

Science.gov (United States)

Xu, Tie-Feng; Li, Guang-Po; Nie, Qiu-Hua; Shen, Xiang

2006-06-01

Er3+/Yb3+ co-doped TeO2-B2O3-Nb2O5-ZnO (TBN) glasses were prepared. The absorption spectra and upconversion luminescence spectra of TBN glasses were measured and analyzed. The upconversion emission bands centered at 530, 546 and 658 nm were observed under the excitation at 975 nm, corresponding to the transitions of 2H11/2-->4I15/2, 4S3/2-->4I15/2 and 4F9/2-->4I15/2 respectively. The ratio of red emission to green emission increases with an increasing of Yb3+ ions concentration. According to the quadratic dependence on excitation power, the possible upconversion mechanisms and processes were discussed.

Spectroscopic and energy transfer studies of Er3+ ions in B2O3-TeO2-MgO-ZnO glasses