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Sample records for curie temperature tc

  1. An efficient control of Curie temperature $T_C$ in Ni-Mn-Ga alloys

    OpenAIRE

    Khovailo, V. V.; Chernenko, V. A.; Cherechukin, A. A.; Takagi, T.; Abe, T.

    2003-01-01

    We have studied the influence of alloying with a fourth element on the temperature of ferromagnetic ordering $T_C$ in Ni-Mn-Ga Heusler alloys. It is found that $T_C$ increases or decreases, depending on the substitution. The increase of $T_C$ is observed when Ni is substituted by either Fe or Co. On the contrary, the substitution of Mn for V or Ga for In strongly reduces $T_C$.

  2. CURIE-TEMPERATURE "SLATER-PAULING CURVE"

    OpenAIRE

    Kakehashi, Y.; Hosohata, O.

    1988-01-01

    The systematic variation of the Curie-temperature "Slater-Pauling curve" has been explained for the first time on the basis of the finite-temperature theory of the local environment effect. The peculiarity of the Curie temperatures in Fe-V, Fe-Ni, and Ni-Mn alloys is elucidated by using the effective exchange couplings.

  3. Calculation of exchange integrals and Curie temperature for La-substituted barium hexaferrites

    Science.gov (United States)

    Wu, Chuanjian; Yu, Zhong; Sun, Ke; Nie, Jinlan; Guo, Rongdi; Liu, Hai; Jiang, Xiaona; Lan, Zhongwen

    2016-10-01

    As the macro behavior of the strength of exchange interaction, state of the art of Curie temperature Tc, which is directly proportional to the exchange integrals, makes sense to the high-frequency and high-reliability microwave devices. Challenge remains as finding a quantitative way to reveal the relationship between the Curie temperature and the exchange integrals for doped barium hexaferrites. Here in this report, for La-substituted barium hexaferrites, the electronic structure has been determined by the density functional theory (DFT) and generalized gradient approximation (GGA). By means of the comparison between the ground and relative state, thirteen exchange integrals have been calculated as a function of the effective value Ueff. Furthermore, based on the Heisenberg model, the molecular field approximation (MFA) and random phase approximation (RPA), which provide an upper and lower bound of the Curie temperature Tc, have been adopted to deduce the Curie temperature Tc. In addition, the Curie temperature Tc derived from the MFA are coincided well with the experimental data. Finally, the strength of superexchange interaction mainly depends on 2b-4f1, 4f2-12k, 2a-4f1, and 4f1-12k interactions.

  4. Critical behavior of the resistivity of GaMnAs near the Curie temperature

    Science.gov (United States)

    Yuldashev, Sh. U.; Yunusov, Z. A.; Kwon, Y. H.; Lee, S. H.; Ahuja, R.; Kang, T. W.

    2017-09-01

    The effect of the magnetization fluctuations on the resistivity of GaMnAs near the Curie temperature TC was experimentally studied. It is shown that the determination of TC from the maximum of the temperature derivative of the resistivity is valid for the samples with a high concentration of free carries. Whereas, for the samples with low concentration of free carriers the TC coincides with the resistivity maximum. The magnetic specific heat for T>TC demonstrates the crossover from the one dimensional to the three dimensional critical behavior when the temperature become closer to the Curie temperature. This is explained by the formation of the ferromagnetic phase in the paramagnetic side of the phase transition which is started from Mn-Mn dimers oriented along one direction.

  5. High Curie temperatures in (Ga,Mn)N from Mn clustering

    OpenAIRE

    Hynninen, Teemu; Raebiger, Hannes; Ayuela, Andres; von Boehm, J.

    2005-01-01

    The effect of microscopic Mn cluster distribution on the Curie temperature (Tc) is studied using density-functional calculations. We find that the calculated Tc depends crucially on the microscopic cluster distribution, which can explain the abnormally large variations in experimental Tc values from a few K to well above room temperature. The partially dimerized Mn_2-Mn_1 distribution is found to give the highest Tc > 500 K, and in general, the presence of the Mn_2 dimer has a tendency to enh...

  6. The mysterious malleability of titanomagnetite Curie temperatures: An update

    Science.gov (United States)

    Jackson, M. J.; Bowles, J.; Lappe, S. C.; Berquo, T. S.; Solheid, P.

    2015-12-01

    Intermediate-composition titanomagnetites (TM30-TM50) have recently been shown to have Curie temperatures (Tc) that depend not only on composition but also quite strongly on thermal history, with increases of 100°C or more in Tc produced by moderate-temperature (300-400° C) annealing in the lab or in slow natural cooling, and equally large decreases produced by more rapid cooling ("quenching") from higher temperatures [e.g., Bowles et al 2013, Nature Communications]. The phenomenon is robustly defined and repeatable, but the underlying mechanism remains enigmatic, although it presumably involves some rearrangement of metal cations within the spinel lattice. New high-and low-temperature measurements, including hysteresis, frequency-dependent AC susceptibility (k(f,T)) and Mössbauer spectroscopy, were carried out to help shed light on the nanoscale mechanisms responsible for the observed changes in Tc. Fabian et al [2015, GJI] have shown for ferrimagnetic compositions in the hematite-ilmenite system that high-T hysteresis measurements exhibit a peak in high-field slope at the Curie temperature, and that the magnitude (area) of this peak is a strong function of cation ordering degree. Our data for synthetic titanomagnetites in quenched and annealed states show some indications of this, although the relationship is not perfectly systematic. On the other hand, our new low-T Mössbauer spectra, measured in the quenched and annealed states, are indistinguishable and argue against any change in site occupancy. Church et al [2011, G3] have proposed that the sharp change in low-T magnetic behavior of intermediate titanomagnetites is a "pinning transition" due to redistribution and localization of ferrous ions within the octahedral sites. Our new k(f,T) results show that the pinning transition in some samples is strongly affected by prior annealing or quenching, suggesting that these treatments affect the intrasite cation distributions. Such an idea is consistent with

  7. Controlling temperature in magnetic hyperthermia with low Curie temperature particles

    Science.gov (United States)

    Astefanoaei, Iordana; Dumitru, Ioan; Chiriac, Horia; Stancu, Alexandru

    2014-05-01

    Hyperthermia induced by the heating of magnetic particles (MPs) in alternating magnetic field receives a considerable attention in cancer therapy. An interesting development in the studies dedicated to magnetically based hyperthermia is the possibility to control the temperature using MPs with selective magnetic absorption properties. This paper analyzes the temperature field determined by the heating of MPs having low Curie temperature (a FeCrNbB particulate system) injected within a malignant tissue, subjected to an ac magnetic field. The temperature evolution within healthy and tumor tissues was analyzed by finite element method simulations in a thermo-fluid model. The cooling effect produced by blood flowing in blood vessels was considered. This effect is intensified at the increase of blood velocity. The FeCrNbB particles, having the Curie temperature close to the therapeutic range, transfer the heat more homogeneous in the tumor keeping the temperature within the therapeutic range in whole tumor volume. Having the possibility to automatically control the temperature within a tumor, these particle type opens new research horizons in the magnetic hyperthermia.

  8. Size and shape effects on Curie temperature of ferromagnetic nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simplified model was developed to describe the Curie temperature suppression of ferromagnetic nanoparticles. Based on a size and shape dependent model of cohesive energy, the critical temperature variations of ferromagnetic nanoparticles were deduced. It is predicted that the Curie temperature of nanoparticles depends on both size and shape conditions, among which the temperature suppression is strongly influenced by the particle size and the shape effect is comparably minor. The calculation values for freestanding nanoparticles are in good agreement with other theoretical model and the experimental results. The model is also potential for predictions for the nanoparticles embedded in different substrates.

  9. Curie temperature of Co-doped TiO2 as functions of carrier density and Co content evaluated from electrical transport and magnetization at low temperature regime

    Directory of Open Access Journals (Sweden)

    Thantip S. Krasienapibal

    2016-05-01

    Full Text Available Curie temperature (TC of anatase Co-doped TiO2 epitaxial thin films was systematically investigated as functions of carrier density (n and Co content (x by electrical transport and magnetization measurements at low temperature regime. The estimated TC from both measurements showed similar TC. For x = 0.03, 0.05, and 0.07, non-monotonic TC vs. n relations were observed, whereas TC was monotonically increasing function of n for x = 0.10. Possible mechanism of high TC ferromagnetism for this compound was discussed.

  10. High Curie temperature BiInO3-PbTiO3 films.

    Science.gov (United States)

    Lee, Sun Young; Wang, Wei; Trolier-McKinstry, Susan

    2014-06-14

    High Curie temperaturepiezoelectricthin films of xBiInO3-(1-x)PbTiO3 (x = 0.10, 0.15, 0.20, and 0.25) were prepared by pulsed laser deposition. It was found that the tetragonality of films decreased with increasing BI content. The dielectric constant and transverse piezoelectric coefficient (e31,f ) exhibit the highest values of 665 and -13.6 C/m(2) at x = 0.20. Rayleigh analyses were performed to identify the extrinsic contributions to dielectric nonlinearity with different x. The composition with x = 0.20 also exhibits the largest extrinsic contributions to dielectric nonlinearity. The Curie temperature (TC ) is increased with increasing x content from 558 to 633 °C; TC at x = 0.20 is about 584 °C.

  11. Studies on the Relation between the Composition of Thermal Sensitive MnZn Ferrite and Curie Temperature

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Thermal sensitive MnZn ferrite is a kind of soft magnetic ferrite material with lower Curie temperature (Tc) and can be used to make many kinds of magnetic thermal sensitive sensors with high sensitivity. In this paper, the relation between the composition of thermal sensitive ferrite and Tc was studied. It was found that Tc changes linearly with ZnO extent when the content of Fe2O3 is fixed. Based on lots of experiments, an experimential formula to determine Tc was given out.

  12. CoxC nanorod magnets: Highly magnetocrystalline anisotropy with lower Curie temperature for potential applications

    Energy Technology Data Exchange (ETDEWEB)

    El-Gendy, AA; Almugaiteeb, T; Carpenter, EE

    2013-12-01

    Magnetic CoxC nanorods with larger magnetocrystalline anisotropy of 5 x 10(5) J/m(3) as well as larger coercivity and lower Curie temperature are introduced. The particles have an average diameter of 8 nm and shows three different magnetic behaviors. The sample shows ferromagnetism up to 400 K, superparamagnetism at temperature > 400 K and <T-C (465 K) and paramagnetism above 465 K. Such different behaviors open the door for various applications such as permanent magnets, magnetic sensors and contract agent for magnetic resonance imaging. (c) 2013 Elsevier B.V. All rights reserved.

  13. Tailoring Curie temperature and magnetic anisotropy in ultrathin Pt/Co/Pt films

    Directory of Open Access Journals (Sweden)

    Vineeth Mohanan Parakkat

    2016-05-01

    Full Text Available The dependence of perpendicular magnetization and Curie temperature (Tc of Pt/Co/Pt thin films on the thicknesses of Pt seed (Pts and presence of Ta buffer layer has been investigated in this work. Pt and Co thicknesses were varied between 2 to 8 nm and 0.35 to 1.31 nm (across the spin reorientation transition thickness respectively and the Tc was measured using SQUID magnetometer. We have observed a systematic dependence of Tc on the thickness of Pts. For 8nm thickness of Pts the Co layer of 0.35nm showed ferromagnetism with perpendicular anisotropy at room temperature. As the thickness of the Pts was decreased to 2nm, the Tc went down below 250K. XRD data indicated polycrystalline growth of Pts on SiO2. On the contrary Ta buffer layer promoted the growth of Pt(111. As a consequence Ta(5nm/Pt(3nm/Co(0.35nm/Pt(2nm had much higher Tc (above 300K with perpendicular anisotropy when compared to the same stack without the Ta layer. Thus we could tune the ferromagnetic Tc and anisotropy by varying the Pts thickness and also by introducing Ta buffer layer. We attribute these observations to the micro-structural evolution of Pts layer which hosts the Co layer.

  14. First-principles calculation of the Curie temperature Slater-Pauling curve.

    Science.gov (United States)

    Takahashi, C; Ogura, M; Akai, H

    2007-09-12

    It is well known that the magnetizations as a function of the valence electron number per atom of 3d transition metal substitutional alloys form the so-called Slater-Pauling curve. Similarly, the Curie temperatures of these alloys also show systematic behaviour against the valence electron number. Though this fact has long been known, no attempt has been made so far to explain this behaviour from first principles. In this paper we calculate T(C) of 3d transition metal alloys in the framework of first-principles electronic structure calculation based on the local density approximation.

  15. Utilizing Materials With Controllable Curie Temperatures for Magnetic Actuation Purposes

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian R.H.; Smith, Anders

    2013-01-01

    The magnetic force between a permanent magnet and different blocks of ferromagnetic materials was measured and calculated as a function of distance and temperature in the vicinity of the Curie temperature of the materials. The calculations were carried out using a 3-D finite-element model...... of the system. On the basis of forces predicted by the model a number of equilibrium points were calculated for a system where the magnetic force on a ferromagnetic block of material is balanced by a linear spring force. It is shown how these calculation procedures can be used as a tool for designing autonomous...

  16. Effect of pressure on the Curie temperature of Mn2RuSn and Mn2PdSn

    Science.gov (United States)

    Adachi, Y.; Watanabe, T.; Kanomata, T.; Hayasaka, M.; Endo, K.; Nishihara, H.; Xu, X.; Kainuma, R.

    2017-04-01

    Effect of pressure on the Curie temperature TC of the Mn-rich Heusler alloys Mn2RuSn and Mn2PdSn has been investigated by measuring the temperature dependence of initial permeability at various pressures up to 10 kbar. It was found that the Curie temperatures of Mn2RuSn and Mn2PdSn decrease with increasing pressure. The pressure derivatives of TC were estimated to be -0.59 K/kbar for Mn2RuSn and -0.80 K/kbar for Mn2PdSn. On the basis of the experimental results, the relationship between the magnetic transition temperature and the Mn-Mn distance is discussed.

  17. Effect of ionic radii on the Curie temperature in Ba1-x-ySrxCayTiO3 compounds

    Science.gov (United States)

    Berenov, A.; Le Goupil, F.; Alford, N.

    2016-06-01

    A series of Ba1-x-ySrxCayTiO3 compounds were prepared with varying average ionic radii and cation disorder on A-site. All samples showed typical ferroelectric behavior. A simple empirical equation correlated Curie temperature, TC, with the values of ionic radii of A-site cations. This correlation was related to the distortion of TiO6 octahedra observed during neutron diffraction studies. The equation was used for the selection of compounds with predetermined values of TC. The effects of A-site ionic radii on the temperatures of phase transitions in Ba1-x-ySrxCayTiO3 were discussed.

  18. Curie temperature rising by fluorination for Sm2Fe17

    Directory of Open Access Journals (Sweden)

    Matahiro Komuro

    2013-02-01

    Full Text Available Fluorine atoms can be introduced to Sm2Fe17 using XeF2 below 423 K. The resulting fluorinated Sm2Fe17 powders have ferromagnetic phases containing Sm2Fe17FY1(0Curie temperature from 403 K for Sm2Fe17 to 675 K. This increase can be explained by the magneto-volume effect.

  19. Enhancement of Curie temperature and transition temperature range induced by Al doping in Mn1-xAlxCoGe

    Science.gov (United States)

    Si, Xiaodong; Liu, Yongsheng; Lei, Wei; Xu, Juan; Du, Wenlong; Lin, Jia; Zhou, Tao; Lu, Xiaofei

    2016-12-01

    Mn1-xAlxCoGe alloys with a second order transition were produced by arc-melting method. The substitution of Mn by Al increased the Curie temperature (TC) from 260.5 K to 300.8 K, the magnetic entropy change (|ΔSM|) decreased from 3.78 J·Kg-1K-1 to 2.35 J·Kg-1K-1 under a field change of Δμ0H=5 T. In addition, the |ΔSM| well linearly depends on the H2/3 around TC. Furthermore, the relative cooling power (RCP) can reach 242.3 J·Kg-1 with a large full width at half maximum of |ΔSM| (75.5 K) for x=0.02. The decrease of |ΔSM| is explained by the corresponding monotonical decrease of magnetic moment per formula unit.

  20. Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature

    Science.gov (United States)

    Li, Jiawei; Huo, Juntao; Law, Jiayan; Chang, Chuntao; Du, Juan; Man, Qikui; Wang, Xinmin; Li, Run-Wei

    2014-08-01

    The effects of heavy rare earth (RE) additions on the Curie temperature (TC) and magnetocaloric effect of the Fe-RE-B-Nb (RE = Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune TC in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (ΔSM) and refrigerant capacity (RC) of the alloys. The observed values of ΔSM and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd5Ge1.9Si2Fe0.1. The tunable TC and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.

  1. Effect of P-anion codoping on the Curie temperature of GaMnAs diluted magnetic semiconductors

    Science.gov (United States)

    Bouzerar, Richard; Máca, Frantisek; Kudrnovský, Josef; Bergqvist, Lars

    2010-07-01

    Recent measurements of GaMnAs alloy samples with a very small content of P atoms prepared by ion-implanted pulsed laser melting (II-PLM) [Phys. Rev. Lett. 101, 087203 (2008)10.1103/PhysRevLett.101.087203] have shown surprisingly low Curie temperature as compared to undoped samples. An explanation based on a possible metal-insulator transition at constant Mn doping was proposed based on a dramatic increase of the sample resistivity. However, no quantitative calculations supporting such a picture as concerns the Curie temperature were shown. We will present a parameter-free theory of the Curie temperature (TC) which assumes that possible defects due to the II-PLM such as, e.g., space inhomogeneities, vacancies, clustering, and also conventional compensating defects will reduce the sample hole concentration. Their effect was first qualitatively modeled in the framework of the rigid-band model by adjusting the system Fermi level due to the reduction of the carrier concentration which is considered as a parameter of the theory. In addition, the effect of possible conventional compensating defects, such as, e.g., As and P antisites or P and Mn interstitials was also investigated. TC ’s are calculated within the self-consistent local RPA (SCLRPA) and Monte Carlo (MC) simulations. We will demonstrate that a reasonable agreement of calculated and measured TC can be obtained for reduced hole concentrations which are known to exist in GaMnAs samples. As concerns possible specific defects, we have shown that P and Mn interstitials are particularly effective in the reduction of the sample Curie temperature.

  2. Estimation of Curie temperature of manganite-based materials for magnetic refrigeration application using hybrid gravitational based support vector regression

    Science.gov (United States)

    Owolabi, Taoreed O.; Akande, Kabiru O.; Olatunji, Sunday O.; Alqahtani, Abdullah; Aldhafferi, Nahier

    2016-10-01

    Magnetic refrigeration (MR) technology stands a good chance of replacing the conventional gas compression system (CGCS) of refrigeration due to its unique features such as high efficiency, low cost as well as being environmental friendly. Its operation involves the use of magnetocaloric effect (MCE) of a magnetic material caused by application of magnetic field. Manganite-based material demonstrates maximum MCE at its magnetic ordering temperature known as Curie temperature (TC). Consequently, manganite-based material with TC around room temperature is essentially desired for effective utilization of this technology. The TC of manganite-based materials can be adequately altered to a desired value through doping with appropriate foreign materials. In order to determine a manganite with TC around room temperature and to circumvent experimental challenges therein, this work proposes a model that can effectively estimates the TC of manganite-based material doped with different materials with the aid of support vector regression (SVR) hybridized with gravitational search algorithm (GSA). Implementation of GSA algorithm ensures optimum selection of SVR hyper-parameters for improved performance of the developed model using lattice distortions as the descriptors. The result of the developed model is promising and agrees excellently with the experimental results. The outstanding estimates of the proposed model suggest its potential in promoting room temperature magnetic refrigeration through quick estimation of the effect of dopants on TC so as to obtain manganite that works well around the room temperature.

  3. Estimation of Curie temperature of manganite-based materials for magnetic refrigeration application using hybrid gravitational based support vector regression

    Directory of Open Access Journals (Sweden)

    Taoreed O. Owolabi

    2016-10-01

    Full Text Available Magnetic refrigeration (MR technology stands a good chance of replacing the conventional gas compression system (CGCS of refrigeration due to its unique features such as high efficiency, low cost as well as being environmental friendly. Its operation involves the use of magnetocaloric effect (MCE of a magnetic material caused by application of magnetic field. Manganite-based material demonstrates maximum MCE at its magnetic ordering temperature known as Curie temperature (TC. Consequently, manganite-based material with TC around room temperature is essentially desired for effective utilization of this technology. The TC of manganite-based materials can be adequately altered to a desired value through doping with appropriate foreign materials. In order to determine a manganite with TC around room temperature and to circumvent experimental challenges therein, this work proposes a model that can effectively estimates the TC of manganite-based material doped with different materials with the aid of support vector regression (SVR hybridized with gravitational search algorithm (GSA. Implementation of GSA algorithm ensures optimum selection of SVR hyper-parameters for improved performance of the developed model using lattice distortions as the descriptors. The result of the developed model is promising and agrees excellently with the experimental results. The outstanding estimates of the proposed model suggest its potential in promoting room temperature magnetic refrigeration through quick estimation of the effect of dopants on TC so as to obtain manganite that works well around the room temperature.

  4. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    Science.gov (United States)

    Chen, Daming; Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (Tc). We prepared aluminum doped barium ferrite ceramics (BaAlxFe12-xO19, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate Tc and magnetic properties of BaFe12-xAlxO19. It is found that Tc decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πMs) decreases with increasing x, while the coercivity (Hc) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement.

  5. High Curie temperature of Ce-Fe-Si compounds with ThMn12 structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, C; Pinkerton, FE; Herbst, JF

    2015-01-15

    We report the discovery of ternary CeFe(12-x)Si(x)compounds possessing the ThMn12 structure. The samples were prepared by melt spinning followed by annealing. In contrast to other known Ce Fe-based binary and ternary compounds, CeFe12-xSix compounds exhibit exceptionally high Curie temperatures whose values increase with added Si substitution. The highest T. = 583 K in CeFe10Si2 rivals that of the well-established Nd2Fe14B compound. We ascribe the T-c behavior to a combination of Si-induced 3d band structure changes and partial Ce3+ stabilization. (C) 2014 Published by Elsevier Ltd.

  6. Nanoengineering of an Si/MnGe quantum dot superlattice for high Curie-temperature ferromagnetism.

    Science.gov (United States)

    Nie, Tianxiao; Kou, Xufeng; Tang, Jianshi; Fan, Yabin; Lee, Shengwei; He, Qinglin; Chang, Li-Te; Murata, Koichi; Gen, Yin; Wang, Kang L

    2017-02-14

    The realization and application of spintronic devices would be dramatically advanced if room-temperature ferromagnetism could be integrated into semiconductor nanostructures, especially when compatible with mature silicon technology. Herein, we report the observation of such a system - an Si/MnGe superlattice with quantum dots well aligned in the vertical direction successfully grown by molecular beam epitaxy. Such a unique system could take full advantage of the type-II energy band structure of the Si/Ge heterostructure, which could trap the holes inside MnGe QDs, significantly enhancing the hole-mediated ferromagnetism. Magnetic measurements indeed found that the superlattice structure exhibited a Curie temperature of above 400 K. Furthermore, zero-field cooling and field cooling curves could confirm the absence of ferromagnetic compounds, such as Ge8Mn11 (Tc ∼ 270 K) and Ge3Mn5 (Tc ∼ 296 K) in our system. Magnetotransport measurement revealed a clear magnetoresistance transition from negative to positive and a pronounced anomalous Hall effect. Such a unique Si/MnGe superlattice sets a new stage for strengthening ferromagnetism due to the enhanced hole-mediation by quantum confinement, which can be exploited for realizing the room-temperature Ge-based spin field-effect transistors in the future.

  7. High-Curie-temperature ferromagnetism in self-organized Ge1-xMnx nanocolumns.

    Science.gov (United States)

    Jamet, Matthieu; Barski, André; Devillers, Thibaut; Poydenot, Valier; Dujardin, Romain; Bayle-Guillemaud, Pascale; Rothman, Johan; Bellet-Amalric, Edith; Marty, Alain; Cibert, Joël; Mattana, Richard; Tatarenko, Serge

    2006-08-01

    The emerging field of spintronics would be dramatically boosted if room-temperature ferromagnetism could be added to semiconductor nanostructures that are compatible with silicon technology. Here, we report a high-TC (>400K) ferromagnetic phase of (Ge,Mn) epitaxial layer. The manganese content is 6%, and careful structural and chemical analyses show that the Mn distribution is strongly inhomogeneous: we observe eutectoid growth of well-defined Mn-rich nanocolumns surrounded by a Mn-poor matrix. The average diameter of these nanocolumns is 3nm and their spacing is 10nm. Their composition is close to Ge(2)Mn, which corresponds to an unknown germanium-rich phase, and they have a uniaxially elongated diamond structure. Their Curie temperature is higher than 400K. Magnetotransport reveals a pronounced anomalous Hall effect up to room temperature. A giant positive magnetoresistance is measured from 7,000% at 30K to 200% at 300K and 9T, with no evidence of saturation.

  8. Effect of Gd doping and O deficiency on the Curie temperature of EuO

    KAUST Repository

    Jutong, Nuttachai

    2015-01-27

    The effect of Gd doping and O deficiency on the electronic structure, exchange interaction, and Curie temperature of EuO in the cubic and tetragonal phases is studied by means of density functional theory. For both defects, the Curie temperature is found to exhibit a distinct maximum as a function of the defect concentration. The existence of optimal defect concentrations is explained by the interplay of the on-site, RKKY, and superexchange contributions to the magnetism.

  9. The study of high Curie temperature ferromagnetism properties in Mn-doped SiC thin film

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    Chaoyang Kang

    2015-01-01

    Full Text Available Mn-doped 3C-SiC film has been prepared onto the Si (111 substrate by employing a molecular beam epitaxy method. The experimental analysis establishes that the prepared sample shows the ferromagnetic property with a relatively high Curie temperature (Tc of 355 K, which is an exciting phenomenon on account of the scarceness in the SiC-based diluted magnetic semiconductor. The analysis derived from the X-ray diffraction and absorption spectroscopy patterns indicates that Mn atoms should react with Si atoms and then form Mn4Si7 compounds. Combined with the theoretical simulation, it is speculated that a new alloy phase of Mn4Si7Cx maybe appear, which should be responsible for the exceptionally high Tc ferromagnetic behavior in the sample.

  10. Structure, electrical properties of Bi(Fe, Co)O3-BaTiO3 piezoelectric ceramics with improved Curie temperature

    Science.gov (United States)

    Zhou, Changrong; Cen, Zhenyong; Yang, Huabin; Zhou, Qin; Li, Weizhou; Yuan, Changlai; Wang, Hua

    2013-02-01

    Dense (1-y)BiFe1-xCoxO3-yBaTiO3 (BFC-BTx, y=0.29, x=0-0.012) high-temperature lead-free ceramics were prepared by the conventional oxide-mixed method and the effects of BiCoO3 modification on microstructural, electrical properties and their Curie temperatures were investigated. The solid solutions show a single phase perovskite structure, and the content of BiCoO3 has a significant effect on the microstructure of ceramics. The BFC-BTx ceramics exhibit improved Curie temperature Tc, together with increased piezoelectric properties. In particular, x=0.6% BFC-BTx ceramics, with a Curie temperature, Tc, of ∼488 °C, show optimum piezoelectric properties of d33=167 pC/N, kp=0.32. The combination of good piezoelectric properties and high Tc makes these ceramics suitable for elevated temperature piezoelectric devices.

  11. Using ferromagnetic nanoparticles with low Curie temperature for magnetic resonance imaging-guided thermoablation

    Directory of Open Access Journals (Sweden)

    Herynek V

    2016-08-01

    Full Text Available Vít Herynek,1 Karolína Turnovcová,2 Pavel Veverka,3 Tereza Dědourková,4,5 Pavel Žvátora,6 Pavla Jendelová,2 Andrea Gálisová,1 Lucie Kosinová,7 Klára Jiráková,2 Eva Syková2 1MR-Unit, Radiodiagnostic and Interventional Radiology Department, Institute for Clinical and Experimental Medicine, Prague, 2Department of Neuroscience, Institute of Experimental Medicine, 3Department of Magnetics and Superconductors, Institute of Physics, Czech Academy of Sciences, Prague, 4Department of Inorganic Technology, Faculty of Chemical Technology, University of Pardubice, 5SYNPO, akciová společnost, Pardubice, 6Department of Analytical Chemistry, Institute of Chemical Technology, 7Diabetes Center, Institute for Clinical and Experimental Medicine, Prague, Czech Republic Introduction: Magnetic nanoparticles (NPs represent a tool for use in magnetic resonance imaging (MRI-guided thermoablation of tumors using an external high-frequency (HF magnetic field. To avoid local overheating, perovskite NPs with a lower Curie temperature (Tc were proposed for use in thermotherapy. However, deposited power decreases when approaching the Curie temperature and consequently may not be sufficient for effective ablation. The goal of the study was to test this hypothesis. Methods: Perovskite NPs (Tc =66°C–74°C were characterized and tested both in vitro and in vivo. In vitro, the cells suspended with NPs were exposed to a HF magnetic field together with control samples. In vivo, a NP suspension was injected into a induced tumor in rats. Distribution was checked by MRI and the rats were exposed to a HF field together with control animals. Apoptosis in the tissue was evaluated. Results and discussion: In vitro, the high concentration of suspended NPs caused an increase of the temperature in the cell sample, leading to cell death. In vivo, MRI confirmed distribution of the NPs in the tumor. The temperature in the tumor with injected NPs did not increase

  12. Enhancing the Curie temperature of ferromagnetic semiconductor (Ga,Mn)As to 200 K via nanostructure engineering.

    Science.gov (United States)

    Chen, Lin; Yang, Xiang; Yang, Fuhua; Zhao, Jianhua; Misuraca, Jennifer; Xiong, Peng; von Molnár, Stephan

    2011-07-13

    We demonstrate by magneto-transport measurements that a Curie temperature as high as 200 K can be obtained in nanostructures of (Ga,Mn)As. Heavily Mn-doped (Ga,Mn)As films were patterned into nanowires and then subject to low-temperature annealing. Resistance and Hall effect measurements demonstrated a consistent increase of T(C) with decreasing wire width down to about 300 nm. This observation is attributed primarily to the increase of the free surface in the narrower wires, which allows the Mn interstitials to diffuse out at the sidewalls, thus enhancing the efficiency of annealing. These results may provide useful information on optimal structures for (Ga,Mn)As-based nanospintronic devices operational at relatively high temperatures.

  13. Enhancement of Curie temperature of barium hexaferrite by dense electronic excitations

    Directory of Open Access Journals (Sweden)

    Manju Sharma

    2014-07-01

    Full Text Available Curie temperature of polycrystalline barium hexaferrite (BaFe12O19, prepared by conventional solid state technique, is anomalously and significantly enhanced (by nearly 15% by energetic heavy ion irradiation (150 MeV, Ag12+ at ambient temperature due to dense electronic excitations Moderate fluence (1 × 1012 ions/cm2 induces structural defects giving rise to above enhancement. As established by X-ray diffraction, scanning electron microscopy and Raman studies, higher fluence (1 × 1013 ions/cm2 has structurally transformed the sample to amorphous phase with marginal change in magnetization and Curie temperature.

  14. Enhancement of Curie temperature of barium hexaferrite by dense electronic excitations

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Manju; Kashyap, Subhash C.; Gupta, Hem C. [Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India); Dimri, Mukesh C. [Ajay Kumar Garg Engineering College, Ghaziabad - 201009 (India); Asokan, K. [Materials Science Group, Inter University Accelerator Center, New Delhi-110067 (India)

    2014-07-15

    Curie temperature of polycrystalline barium hexaferrite (BaFe{sub 12}O{sub 19}), prepared by conventional solid state technique, is anomalously and significantly enhanced (by nearly 15%) by energetic heavy ion irradiation (150 MeV, Ag{sup 12+}) at ambient temperature due to dense electronic excitations Moderate fluence (1 × 10{sup 12} ions/cm{sup 2}) induces structural defects giving rise to above enhancement. As established by X-ray diffraction, scanning electron microscopy and Raman studies, higher fluence (1 × 10{sup 13} ions/cm{sup 2}) has structurally transformed the sample to amorphous phase with marginal change in magnetization and Curie temperature.

  15. Curie Temperature and Microstructural Changes Due to the Heating Treatment of Magnetic Amorphous Materials

    Directory of Open Access Journals (Sweden)

    Gondro J.

    2016-03-01

    Full Text Available Three distinct alloys: Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8, and Fe81Pt5Zr7Nb1Cu1B5 were characterized both magnetically and structurally. The samples, obtained with spinning roller method as a ribbons 3 mm in width and 20 μm thick, were investigated as-quenched and after each step of a multi steps heating treatment procedure. Each sample was annealed at four steps, fifteen minutes at every temperature, starting from 573K+600K up to +700K depending on type of alloy. Mössbauer spectroscopy data and transmission electron microscope (HRE M pictures confirmed that the as-quenched samples are fully amorphous. This is not changed after the first stages of treatment heating leads to a reduction of free volumes. The heating treatment has a great influence on the magnetic susceptibilities. The treatment up to 600K improves soft magnetic properties: an χ increase was observed, from about 400 to almost 1000 for the samples of alloys without Pt, and from about 200 to 450 at maximum, for the Fe81Pt5Zr7Nb1Cu1B5. Further heating, at more elevated temperatures, leads to magnetic hardening of the samples. Curie temperatures, established from the location of Hopkinson’s maxima on the χ(T curve are in very good agreement with those obtained from the data of specific magnetization, σ(T, measured in a field of 0.75T. As a critical parameter β was chosen to be equal 0.36 for these calculations, it confirmed that the alloys may be considered as ferromagnetic of Heisenberg type. Heating treatment resulted in decreasing of TC. These changes are within a range of several K.

  16. Curie temperatures of dilute magnetic semiconductors from LDA+U electronic structure calculations

    Energy Technology Data Exchange (ETDEWEB)

    Sato, K. [ISIR, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)]. E-mail: ksato@cmp.sanken.osaka-u.ac.jp; Dederichs, P.H. [IFF, Forschungszentrum Juelich, D-52425 Juelich (Germany); Katayama-Yoshida, H. [ISIR, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2006-04-01

    The magnetic properties of dilute magnetic semiconductors (DMS) are calculated by using the local density approximation +U(LDA+U) method. In the LDA+U, occupied d-states in (Ga, Mn)As are predicted at lower energy than in the LDA and p-d exchange interaction explains calculated concentration dependence of Curie temperature very well. In (Ga, Mn)N, unoccupied d states are predicted at higher energy by LDA+U, resulting in higher Curie temperatures than in LDA at high concentrations due to the suppression of the anti-ferromagnetic super-exchange interaction.

  17. Nickel Curie Point Engine

    Science.gov (United States)

    Chiaverina, Chris; Lisensky, George

    2014-01-01

    Ferromagnetic materials such as nickel, iron, or cobalt lose the electron alignment that makes them attracted to a magnet when sufficient thermal energy is added. The temperature at which this change occurs is called the "Curie temperature," or "Curie point." Nickel has a Curie point of 627 K, so a candle flame is a sufficient…

  18. Influence of inherent strain on the curie temperature of rare earth ion-doped bismuth vanadate

    OpenAIRE

    Sooryanarayana, K; Row, TNG; R. Somashekar; Varma, KBR

    1998-01-01

    X-ray line broadening is found to be an effective parameter to estimate the strain associated with rare earth ion (Gd3+)-doped polycrystalline bismuth vanadate(Bi2VO5.5). The strain increases with increasing Gd3+ concentration. It is anisotropic and found to be maximum in (111) plane. The Curie temperature which is known to decrease with increase in the rare earth ion concentration in these compounds is correlated with increase in strain.

  19. Investigations on electronic, Fermi surface, Curie temperature and optical properties of Zr2CoAl

    Science.gov (United States)

    Wei, Xiao-Ping; Sun, Weiwei; Zhang, Ya-Ling; Sun, Xiao-Wei; Song, Ting; Wang, Ting; Zhang, Jia-Liang; Su, Hao; Deng, Jian-Bo; Zhu, Xing-Feng

    2017-03-01

    Using full-potential local-orbital minimum-basis along with spin-polarized relativistic Korringa-Kohn-Rostoker methods, we study the electronic, Fermi surface, Curie temperature and optical properties of Zr2CoAl alloy. The alloy with Li2AgSb and Cu2MnAl structures are compared in terms of magnetic properties, and the electronic structures in two structures are also discussed. According to the calculated electronic states, it finds that the Zr2CoAl with Li2AgSb structure is half-metallic ferromagnet with an integral magnetic moment of 2.00μB , meanwhile we also notice the d-d and p-d hybridizations are responsible for the formation of minority-spin gap, furthermore, the fat-bands are applied to discuss the mixture between d and p electrons in the vicinity of the Fermi level. The Fermi surfaces related to the valence bands are constructed, and it is found that the spin-up valence bands 26, 27 and 28 across the Fermi energy dominate the nature of electrons. By mapping the system onto a Heisenberg Hamiltonian, we obtain the exchange coupling parameters, and observe that the Zr(A)-Co(C) and Zr(A)-Zr(B) interactions provide a major contribution for exchange interactions. Based on the calculated exchange coupling parameters, the Curie temperature is estimated to be 287.86 K at equilibrium, and also the dependence of Curie temperature on lattice constant related to the tunable Curie temperature in Zr2CoAl alloy is studied. Finally, we report the optical properties of Zr2CoAl alloy, and present the photon energy dependence of the absorption, the optical conductivity and the loss function.

  20. A new approach to increase the Curie temperature of Fe-Mo double perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Rubi, D. [Institut de Ciencia de Materials de Barcelona, Campus UAB, E-08193, Bellaterra (Spain); Frontera, C. [Institut de Ciencia de Materials de Barcelona, Campus UAB, E-08193, Bellaterra (Spain); Roig, A. [Institut de Ciencia de Materials de Barcelona, Campus UAB, E-08193, Bellaterra (Spain); Nogues, J. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalunya (Spain); Institut Catala de Recerca i Estudis Avancats (ICREA), 08193 Bellaterra, Catalunya (Spain); Munoz, J.S. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalunya (Spain); Fontcuberta, J. [Institut de Ciencia de Materials de Barcelona, Campus UAB, E-08193, Bellaterra (Spain)]. E-mail: fontcuberta@icmab.es

    2006-01-25

    Sr{sub 2}FeMoO{sub 6} and related double perovskites are nowadays intensely investigated due to their potential in the field of spintronics. It has been previously shown that the Curie temperature (T {sub C}) of double perovskites can be increased by injecting carriers in the conduction band. We report here on an alternative approach to reinforce the magnetic interaction, and thus raise T {sub C}. It can be suspected that the introduction of Fe excess in the Fe-Mo sub-lattice, which would lead into the appearance of nearest neighbour Fe-O-Fe antiferromagnetic spin coupling, could reinforce the next-near neighbour Fe-O-Fe-O-Fe ferromagnetic ordering and thus raise the Curie temperature. The plausibility of this mechanism was checked, in the first place, by means of Monte Carlo simulations. Afterwards, Nd{sub 2x}Ca{sub 2-2x}Fe{sub 1+x}Mo{sub 1-x}O{sub 6} series was prepared and fully characterized, being found that the Curie temperature rises as much as {delta}T {sub C} {approx} 75 K when the Fe content is increased. We argue that this is a genuine magnetic exchange effect, not related neither to steric distortions nor band filling.

  1. Enhancement of Curie Temperature and Magnetoresistance in the Perovskites La2/3Ca1/3Mn1-xSixO3

    Institute of Scientific and Technical Information of China (English)

    LI Run-Wei; WANG Zhi-Hong; SUN Ji-Rong; CHEN Xin; SHEN Bao-Gen

    2000-01-01

    Structural, magnetic, and transport properties of perovskite La2/3Ca1/3Mn1-xSixO3 (x=0, 0.025, 0.05) have been studied. The incorporation of Si decreases the overall resistivity, but obviously increases the Curie temperature (Tc), metal-insulator transition temperature (Tp), and the magnetoresistance ratio MR (defined as [R(0)-R(H)]/R(O)) near room temperature. Comparing with La2/3Ca1/3MnO3, the Tc, Tp, and MR of the sample with x=0.05 increase by 30, 45K, and 20%, respectively. Lattice effects may play a more important role than the magnetic dilution in the case of low Si substitution.

  2. Local radiofrequency-induced hyperthermia using CuNi nanoparticles with therapeutically suitable Curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, Anatoly A. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation); Leontiev, Vladimir G. [Institute of Metallurgy, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation); Brukvin, Vladimir A. [Institute of Metallurgy, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation); Vorozhtsov, Georgy N. [NIOPIK Organic Intermediates and Dyes Institute, Moscow 103787 (Russian Federation); Kogan, Boris Ya. [NIOPIK Organic Intermediates and Dyes Institute, Moscow 103787 (Russian Federation); Shlyakhtin, Oleg A. [Institute of Chemical Physics, Russian Academy of Sciences (RAS), Kosygin St. 4, Moscow 119991 (Russian Federation); Yunin, Alexander M. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation); Tsybin, Oleg I. [Institute of Metallurgy, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation); Kuznetsov, Oleg A. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation)]. E-mail: kuznetsov_oa@yahoo.com

    2007-04-15

    Copper-nickel (CuNi) alloy nanoparticles with Curie temperatures (T{sub c}) from 40 to 60{sup o}C were synthesized by several techniques. Varying the synthesis parameters and post-treatment, as well as separations by size and T{sub c}, allow producing mediator nanoparticles for magnetic fluid hyperthermia with parametric feedback temperature control with desired parameters. In vitro and in vivo animal experiments have demonstrated the feasibility of the temperature-controlled heating of the tissue, laden with the particles, by an external alternating magnetic field.

  3. ESR study of thermal demagnetization processes in ferromagnetic nanoparticles with Curie temperatures between 40 and 60 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, Oleg A. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Kosygin St. 4, Moscow 119991 (Russian Federation)]. E-mail: kuznetsov_oa@yahoo.com; Sorokina, Olga N. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Kosygin St. 4, Moscow 119991 (Russian Federation); Leontiev, Vladimir G. [Institute of Metallurgy, Russian Academy of Sciences (RAS), Moscow 119991 (Russian Federation); Shlyakhtin, Oleg A. [Institute of Chemical Physics, Russian Academy of Sciences (RAS), Kosygin St. 4, Moscow 119991 (Russian Federation); Kovarski, Alexander L. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Kosygin St. 4, Moscow 119991 (Russian Federation); Kuznetsov, Anatoly A. [Institute of Biochemical Physics, Russian Academy of Sciences (RAS), Kosygin St. 4, Moscow 119991 (Russian Federation)

    2007-04-15

    Thermal demagnetization in the vicinity of the Curie temperature of silver and sodium manganite nanoparticles, as well as copper-nickel and palladium-nickel alloy nanoparticles were studied by both static magnetic measurements and by electron spin resonance (ESR). ESR data indicate that some magnetic ordering remains even above the Curie temperature, determined by static magnetometry. Mechanisms of thermal demagnetization in alloy nanoparticles appear to be different from that in manganites.

  4. Magnetic properties of N-doped graphene with high Curie temperature

    Science.gov (United States)

    Miao, Qinghua; Wang, Lidong; Liu, Zhaoyuan; Wei, Bing; Xu, Fubiao; Fei, Weidong

    2016-01-01

    N-doped graphene with Curie temperature higher than room temperature is a good candidate for nanomagnetic applications. Here we report a kind of N-doped graphene that exhibits ferromagnetic property with high Curie temperature (>600 K). Four graphene samples were prepared through self-propagating high-temperature synthesis (SHS), and the doped nitrogen contents of in the samples were 0 at.%, 2.53 at.%, 9.21 at.% and 11.17 at.%. It has been found that the saturation magnetization and coercive field increase with the increasing of nitrogen contents in the samples. For the sample with the highest nitrogen content, the saturation magnetizations reach 0.282 emu/g at 10 K and 0.148 emu/g at 300 K; the coercive forces reach 544.2 Oe at 10 K and 168.8 Oe at 300 K. The drop of magnetic susceptibility at ~625 K for N-doped graphene is mainly caused by the decomposition of pyrrolic N and pydinic N. Our results suggest that SHS method is an effective and high-throughput method to produce N-doped graphene with high nitrogen concentration and that N-doped graphene produced by SHS method is promising to be a good candidate for nanomagnetic applications. PMID:26907569

  5. Structure and Curie temperature of Y2Fe17-xCrx

    Institute of Scientific and Technical Information of China (English)

    郝世强; 陈难先

    2003-01-01

    The structures of Y2Fe17-xCrx are simulated by the ab initio potentials. The site preference of Cr atom in Y2Fe17 is evaluated and the order is determined as 4f, 12j, which is close to the experimental result. Based on the site preference behavior, the calculated parameters and the atom sites of Y-Fe-Cr system are studied. The result corresponds well to observed data. Further, the DOS of the relaxed structures are calculated and the variation in Curie temperature is explained qualitatively by the spin-fluctuation theory.

  6. Curie Temperature of the Intergranular Amorphous Phase in Nanocrystalline Fe89Zr7B4 Alloy

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The FeZrB amorphous alloys for simulating the intergranular amorphous phase in the nanocrystalline Fe89Zr7B4 soft magnetic materials were obtained by mechanical alloying of a mixture of elemental Fe, Zr and B powdersfor 25 h. It is shown that the Curie temperature of the simulated intergranular phase alloy is much lower than thatof the intergranular phase with the same chemical composition in the nanocrystalline Fe89Zr7B4 alloy. The possiblemechanism is mainly due to the strong ferromagnetic exchange force among the nanocrystalline α-Fe grains.

  7. Volume dependence of the exchange interaction and Curie temperature in Co2MGa (M = Ti and Fe): A first-principles study

    Science.gov (United States)

    Liu, X. B.; Altounian, Z.

    2011-04-01

    Magnetic moment, exchange interaction and Curie temperature (TC) have been calculated for Co2TiGa and Co2FeGa by a first-principles density functional calculation combined with a linear response method. The exchange interaction is dominated by Co-Co pairs in Co2TiGa while that of Co2FeGa is mainly contributed by Fe-Co pairs. Based on the mean field multiple-sublattices model, the estimated TC is about 114 K for M = Ti and 1270 K for M = Fe, calculated with the experimental lattice constant, in good agreement with the experimental values (128 K and 1093 K for M = Ti and Fe, respectively). With increasing lattice constant, a, from 95% to 105% of the experimental value (aexp .), the moment per formula unit mf.u. changes from 0.43 μB to 1.0 μB and TC increases from 27 K to 142 K in Co2TiGa. However, mf.u. increases slightly from 4.98 μB to 5.40 μB while TC decreases from 1330 K to 1190 K with increasing a from 95% to 105% of aexp . in Co2FeGa. These different volume dependences of TC are ascribed to the weak ferromagnetism in Co2TiGa and the strong ferromagnetism in Co2FeGa.

  8. Synthesis and characterization of Ni–Cu alloy nanoparticles with a tunable Curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ferk, Gregor [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); Stergar, Janja [Faculty of Medicine, University of Maribor (Slovenia); Makovec, Darko [Department for Materials Synthesis, Jožef Stefan Institute, Ljubljana (Slovenia); Hamler, Anton [Faculty of Electrical Engineering and Computer Science, University of Maribor (Slovenia); Jagličić, Zvonko [Institute of Mathematics, Physics and Mechanics and Faculty of Civil and Geodetic Engineering, University of Ljubljana (Slovenia); Drofenik, Miha [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); Department for Materials Synthesis, Jožef Stefan Institute, Ljubljana (Slovenia); Ban, Irena [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); Center of Excellence NAMASTE, Ljubljana (Slovenia)

    2015-11-05

    A series of nickel–copper alloy magnetic nanoparticles with a range of Curie points from 51 °C to 63 °C were prepared by the reduction of intimately mixed nickel and copper oxides in a silica matrix using the sol–gel method. The silica matrix was subsequently removed with an etching solution, assisted by sonication. The alloy nanoparticles were characterized using X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA/SDTA), thermomagnetic analysis (TMA), transmission electron microscopy (TEM), magnetic measurements (SQUID, vibrating-sample magnetometer) and specific absorption rate measurements (SAR). The synthesized nanoparticles show a size in the range 15–20 nm, exhibited superparamagnetic behavior with a blocking temperature (T{sub B}) of approximately 135 K and a room-temperature magnetization of 3–9 emu/g, depending on the composition. The nanoparticles showed a relatively high effective anisotropy constant (K{sub eff}) and a significant heating ability in an alternating magnetic field. The synthesis method is straightforward and allows the preparation of homogeneous Ni–Cu alloy nanoparticles with a relatively narrow particle size distribution. - Highlights: • Straightforward so-gel synthesis of homogeneous Ni–Cu alloy nanoparticles. • Narrow particle size distribution and controlled Curie point. • Applications in “self-regulating magnetic fluid hyperthermia”. • Heating efficiency of nanoparticles as a function of composition and size.

  9. Nd-doped ZnO monolayer: High Curie temperature and large magnetic moment

    Science.gov (United States)

    Tan, Changlong; Sun, Dan; Zhou, Long; Tian, Xiaohua; Huang, Yuewu

    2016-10-01

    We performed first-principles calculations within density-functional theory to study the structural, electronic, and magnetic properties of Nd-doped ZnO monolayer. The calculated results reveal that Nd-doped ZnO monolayer exhibits stable room temperature ferromagnetism with a large saturation magnetic moment of 3.99 μB per unit in ZnO monolayer. The magnetic property is contributed to the localized f sates of Nd atoms. When two Zn atoms are substituted by two Nd dopants, they tend to form ferromagnetic (FM) coupling and the estimated Curie temperature is higher than room temperature. More interesting, the impurity bands appear within the band gap of ZnO monolayer due to the introduction of Nd dopant. Our results may provide a reference for modifying the material property of ZnO monolayer and are promising as nanoscale building block in spintronic devices.

  10. Marie Curie; Marie Curie

    Energy Technology Data Exchange (ETDEWEB)

    Trotereau, J.

    2011-07-01

    The legend has only retained from Marie Curie (1867-1934) the image of a hard and brilliant worker, pioneer in the radioactivity domain, and who awarded twice the Nobel Price. Behind the scientist, there is a women, Marya Salomea Sklodowska, the 'Polish', who was considered during some time as an 'alien', an 'atheistic intellectual', an 'emancipated women'. When she died alone in July 1934, after an exhausting life of labour, her funeral led to no official ceremony or speech. This small book summarizes the biography of the most famous female scientist in the world

  11. Mapping Curie temperature depth in the western United States with a fractal model for crustal magnetization

    Science.gov (United States)

    Bouligand, C.; Glen, J.M.G.; Blakely, R.J.

    2009-01-01

    We have revisited the problem of mapping depth to the Curie temperature isotherm from magnetic anomalies in an attempt to provide a measure of crustal temperatures in the western United States. Such methods are based on the estimation of the depth to the bottom of magnetic sources, which is assumed to correspond to the temperature at which rocks lose their spontaneous magnetization. In this study, we test and apply a method based on the spectral analysis of magnetic anomalies. Early spectral analysis methods assumed that crustal magnetization is a completely uncorrelated function of position. Our method incorporates a more realistic representation where magnetization has a fractal distribution defined by three independent parameters: the depths to the top and bottom of magnetic sources and a fractal parameter related to the geology. The predictions of this model are compatible with radial power spectra obtained from aeromagnetic data in the western United States. Model parameters are mapped by estimating their value within a sliding window swept over the study area. The method works well on synthetic data sets when one of the three parameters is specified in advance. The application of this method to western United States magnetic compilations, assuming a constant fractal parameter, allowed us to detect robust long-wavelength variations in the depth to the bottom of magnetic sources. Depending on the geologic and geophysical context, these features may result from variations in depth to the Curie temperature isotherm, depth to the mantle, depth to the base of volcanic rocks, or geologic settings that affect the value of the fractal parameter. Depth to the bottom of magnetic sources shows several features correlated with prominent heat flow anomalies. It also shows some features absent in the map of heat flow. Independent geophysical and geologic data sets are examined to determine their origin, thereby providing new insights on the thermal and geologic crustal

  12. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daming [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States); College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan (China); Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States)

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (T{sub c}). We prepared aluminum doped barium ferrite ceramics (BaAl{sub x}Fe{sub 12−x}O{sub 19}, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate T{sub c} and magnetic properties of BaFe{sub 12−x}Al{sub x}O{sub 19}. It is found that T{sub c} decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πM{sub s}) decreases with increasing x, while the coercivity (H{sub c}) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement. - Highlights: • The Curie temperature and magnetic properties of aluminum doped barium ferrite particles were studied systemically. • The relation between 4πM{sub s} and composition x at 50 K (both experimental value and theoretical calculation) was revealed. • Occupation number for spin up and spin down as a function of temperature was shown. • The relation between 4πM{sub s} and composition x from 50 K to room temperature was revealed.

  13. Giant magnetocaloric effect in isostructural MnNiGe-CoNiGe system by establishing a Curie-temperature window

    KAUST Repository

    Liu, E. K.

    2013-03-28

    An effective scheme of isostructural alloying was applied to establish a Curie-temperature window in isostructural MnNiGe-CoNiGe system. With the simultaneous accomplishment of decreasing structural-transition temperature and converting antiferromagnetic martensite to ferromagnetic state, a 200 K Curie-temperature window was established between Curie temperatures of austenite and martensite phases. In the window, a first-order magnetostructural transition between paramagnetic austenite and ferromagnetic martensite occurs with a sharp jump in magnetization, showing a magnetic entropy change as large as −40 J kg−1 K−1 in a 50 kOe field change. This giant magnetocaloric effect enables Mn1− x Co x NiGe to become a potential magnetic refrigerant.

  14. In-Situ Alignment of MnBi Crystals Induced by High Magnetic Field above Curie Temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-Sheng; ZHANG Jin-Cang; REN Zhong-Ming; CAO Shi-Xun

    2007-01-01

    @@ Above Curie temperature, MnBi crystals are aligned in situ along the c-axis in a Bi matrix by a high fabrication magnetic field Hf of 10 T. Magnetic testing shows a pronounced anisotropy in magnetization in directions normal and parallel to the fabrication field, resulting from the alignment. The successful alignment may result from the fact that the easy magnetization direction is along the c-axis of MnBi and the high fabrication field of 10 T is large enough to rotate the MnBi crystal to this direction even though the temperature is above the Curie temperature.

  15. High Curie temperature Mn5Ge3 thin films produced by non-diffusive reaction

    Science.gov (United States)

    Assaf, E.; Portavoce, A.; Hoummada, K.; Bertoglio, M.; Bertaina, S.

    2017-02-01

    Polycrystalline Mn5Ge3 thin films were produced on SiO2 using magnetron sputtering and reactive diffusion (RD) or non-diffusive reaction (NDR). In situ X-ray diffraction and atomic force microscopy were used to determine the layer structures, and magnetic force microscopy, superconducting quantum interference device, and ferromagnetic resonance were used to determine their magnetic properties. RD-mediated layers exhibit similar magnetic properties as molecular beam epitaxy-grown monocrystalline Mn5Ge3 thin films, while NDR-mediated layers show magnetic properties similar to monocrystalline C-doped Mn5Ge3Cx thin films with 0.1 ≤ x ≤ 0.2. NDR appears as a complementary metal oxide semi-conductor-compatible efficient method to produce good magnetic quality high-Curie temperature Mn5Ge3 thin films.

  16. Band filling dependence of the Curie temperature in CrO2

    Science.gov (United States)

    Solovyev, I. V.; Kashin, I. V.; Mazurenko, V. V.

    2016-06-01

    Rutile CrO2 is an important half-metallic ferromagnetic material, which is also widely used in magnetic recording. In an attempt to find the conditions, which lead to the increase of the Curie temperature (T C), we study theoretically the band-filling dependence of interatomic exchange interactions in the rutile compounds. For these purposes, we use the effective low-energy model for the magnetic t 2g bands, derived from the first-principles electronic structure calculations in the Wannier basis, which is solved by means of dynamical mean-field theory. After the solution, we calculate the interatomic exchange interactions, by using the theory of infinitesimal spin rotations, and evaluate T C. We argue that, as far as the Curie temperature is concerned, the band filling realized in CrO2 is far from being the optimal one and much higher T C can be obtained by decreasing the number of t 2g electrons (n) via the hole doping. We find that the optimal n is close to 1, which should correspond to the case of VO2, provided that it is crystallized in the rutile structure. This finding was confirmed by using the experimental rutile structure for both CrO2 and VO2 and reflects the general tendency towards ferromagnetism for the narrow-band compounds at the beginning of the band filling. In particular, our results suggest that the strong ferromagnetism can be achieved in the thin films of VO2, whose crystal structure is controlled by the substrate.

  17. Influence of Non—Magnetic Substitutional Atoms on Spontaneous Moment and Curie Temperature of Ce2Co17Compounds

    Institute of Scientific and Technical Information of China (English)

    胡社军; 刘正义; 等

    2002-01-01

    The structure and magnetic properties of Ce2Co17-xMx(M=Ga,Al and Si)compounds for Mcomcentrations up to x=5 were studied by means of X-ray diffraction and magnetic measurements,The experimental results show that the Curie temperatures and Co spontaneous magnetization decrease significantly with increasing the addition of non-magnetic substitutional atoms,and that Si which has a minimum solid solubility ic Ce2Co17causes a largest reduction of Curie temperature,spontaneous magnetization and moment perCo atom compared with Ga and Al.

  18. Influence of Non-Magnetic Substitutional Atoms on Spontaneous Moment and Curie Temperature of Ce2Co17 Compounds

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The structure and magnetic properties of Ce2Co17-xMx(M=Ga,Al and Si) compounds for M concentrations up to x=5 were studied by means of X-ray diffraction and magnetic measurements. The experimental results show that the Curie temperatures and Co spontaneous magnetization decrease significantly with increasing the addition of non-magnetic substitutional atoms, and that Si which has a minimum solid solubility in Ce2Co17 causes a largest reduction of Curie temperature, spontaneous magnetization and moment per Co atom compared with Ga and Al.

  19. Precise tuning of the Curie temperature of (Ga,Mn)As-based magnetic semiconductors by hole compensation: Support for valence-band ferromagnetism

    Science.gov (United States)

    Zhou, Shengqiang; Li, Lin; Yuan, Ye; Rushforth, A. W.; Chen, Lin; Wang, Yutian; Böttger, R.; Heller, R.; Zhao, Jianhua; Edmonds, K. W.; Campion, R. P.; Gallagher, B. L.; Timm, C.; Helm, M.

    2016-08-01

    For the prototype diluted ferromagnetic semiconductor (Ga,Mn)As, there is a fundamental concern about the electronic states near the Fermi level, i.e., whether the Fermi level resides in a well-separated impurity band derived from Mn doping (impurity-band model) or in the valence band that is already merged with the Mn-derived impurity band (valence-band model). We investigate this question by carefully shifting the Fermi level by means of carrier compensation. We use helium-ion implantation, a standard industry technology, to precisely compensate the hole doping of GaAs-based diluted ferromagnetic semiconductors while keeping the Mn concentration constant. We monitor the change of Curie temperature (TC) and conductivity. For a broad range of samples including (Ga,Mn)As and (Ga,Mn)(As,P) with various Mn and P concentrations, we observe a smooth decrease of TC with carrier compensation over a wide temperature range while the conduction is changed from metallic to insulating. The existence of TC below 10 K is also confirmed in heavily compensated samples. Our experimental results are naturally explained within the valence-band picture.

  20. DFT+ U study of electronic structure and Curie temperature of A2 B ReO6 (A=Sr, Ca and B=Cr, Fe)

    Science.gov (United States)

    Lee, Alex; Marianetti, Chris

    Re-based double perovskites (DPs) have attracted much attention due to their high Curie temperature (TC) and colossal magneto resistance with large potential for spintronic applications. Here we investigate the electronic and magnetic properties of the Re-based DPs A2 B ReO6 (A=Sr, Ca and B=Cr, Fe) using density functional theory + U (DFT+ U) calculations. While monoclinic Ca2CrReO6 and Ca2FeReO6 (monoclinic) are insulating within GGA+ U, tetragonal Sr2CrReO6 (a0a0c0) and Sr2FeReO6 (a0a0c-) remain metallic. We show that both on-site interaction U and octahedral tilting are critical to obtain the insulating phases. The a0a0c- -phase of Sr2CrReO6 is most stable and insulating with nonzero U, suggesting that the high quality Sr2CrReO6 film on STO substrate can be a semiconductor as reported in recent experiments. We explain that the insulator-to-metal transition (MIT) of Ca2FeReO6 at 140K is predominantly due to a structural phase transition which drives the insulating state. Curie temperatures of Re-based DPs are calculated using the classical Monte Carlo simulations based on the Heisenberg model.

  1. Ab initio theory of exchange interactions and the Curie temperature of bulk Gd

    CERN Document Server

    Turek, I; Bihlmayer, G; Bluegel, S

    2003-01-01

    An ab initio approach to the magnetic properties of bulk hexagonal Gd is developed that is based on the local spin-density approximation with the 4f electrons treated as localized core electrons. The effective one-electron problem is solved using the tight-binding linear muffin-tin orbital method in the atomic-sphere approximation with the valence basis consisting of s-, p-and d-type orbitals. The approach leads to a correct description of the ground-state properties like the stability of the ferromagnetic structure, the magnetic moment and the equilibrium lattice constant. Application of a real-space Green-function formalism yields the exchange pair interactions between distant neighbours that are inevitable for quantitative studies of magnetic excitations. The distance dependence and anisotropy of the exchange pair interactions are presented and the Curie temperature in the mean-field approximation is evaluated. The obtained value of 334 K is in much better agreement with the experimental value of 293 K tha...

  2. Observation of a low Curie temperature ferromagnetic phase of ultrathin epitaxial Fe films on GaAs(0 0 1)

    Energy Technology Data Exchange (ETDEWEB)

    Spangenberg, M. [Joule Physics Laboratory, The Crescent, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Neal, J.R. [Joule Physics Laboratory, The Crescent, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Shen, T.-H. [Joule Physics Laboratory, The Crescent, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom)]. E-mail: t.shen@salford.ac.uk; Morton, S.A. [Department of Chemistry and Materials Science, Lawrence Livermore National Laboratory, CA 94550 (United States); Tobin, J.G. [Department of Chemistry and Materials Science, Lawrence Livermore National Laboratory, CA 94550 (United States); Waddill, G.D. [Department of Physics, University of Missouri-Rolla, Rolla, MO 65409 (United States); Matthew, J.A.D. [Department of Physics, University of York, York YO1 5DD (United Kingdom); Greig, D. [Department of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Malins, A.E.R. [CLRC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Seddon, E.A. [CLRC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Hopkinson, M. [EPSRC National Centre for III-V Technologies, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

    2005-04-15

    The magnetic properties of epitaxial Fe films on GaAs in the range of the first few monolayers have been the subject of a considerable number of investigations in recent years. The absence of magnetic signatures at room temperature has been attributed to the existence of a magnetic 'dead' layer as well as superparamagnetism. By examining the temperature dependence of the magnetic linear dichroism of the Fe core level photoelectrons, we found a ferromagnetic regime with a Curie temperature, T {sub c} substantially lower than room temperature, e.g., a T {sub c} of about 240 K for thin films of a nominal thickness of 0.9 nm. The values of Curie temperature were sensitive to the initial GaAs substrate conditions and the thickness of the Fe over-layer with a layer of thickness of 1.25 nm showing a T {sub c} above room temperature. The data suggest that the thin Fe films on GaAs(0 0 1) may have ferromagnetic character at an earlier stage of growth than previously expected, although a weaker exchange interaction in the films leads to a substantial reduction in Curie temperature.

  3. Spin correlations in (Mn,Fe2(P,Si magnetocaloric compounds above Curie temperature

    Directory of Open Access Journals (Sweden)

    X.F. Miao

    2016-06-01

    Full Text Available The longitudinal-field muon-spin relaxation (LF-μSR technique was employed to study the spin correlations in (Mn,Fe2(P,Si compounds above the ferromagnetic transition temperature (TC. The (Mn,Fe2(P,Si compound under study is found to show itinerant magnetism. The standard deviation of the magnetic field distribution of electronic origin increases with a decrease in temperature, which is attributed to the development of spin correlations. The anomalously low magnetic fluctuation rate is suggested to be another signature of the spin correlations. The development of pronounced magnetic fluctuations is in agreement with the observed deviation of the paramagnetic susceptibility from Curie–Weiss behavior. Our study sheds light on the magneto-elastic transition and the mixed magnetism in (Mn,Fe2(P,Si compounds.

  4. Magnetocaloric effect in high Gd content Gd-Fe-Al based amorphous/nanocrystalline systems with enhanced Curie temperature and refrigeration capacity

    Directory of Open Access Journals (Sweden)

    Linlin Zhang

    2016-03-01

    Full Text Available The Gd-Fe-Al amorphous/nanocrystalline composites were successfully designed and obtained with both high Curie temperature (Tc and large magnetic entropy change (ΔSM. The Tc can be tuned from 172 to 280 K and refrigeration capacity (RC has a value between 690 and 867 J/kg under a field change of 0–5 T by changing the Gd contents and the formation of Gd nanocrystallites. And, ΔSM in Gd-Fe-Al amorphous/nanocrystalline composites reached a value of 7.2 J kg−1 K−1 under a field change of 0–5 T. The high RC in Gd-Fe-Al system were ascribed to the widening full width at half maximum (δFWHM up to 240 K of the magnetic entropy change (ΔSMmax peak because of the combination contribution of amorphous matrix and the precipitated Gd-riched nanocrystalline. Our research would shed light on how to design attractive candidates for magnetic refrigeration materials with high performance at near room temperature.

  5. Marie Curie

    National Research Council Canada - National Science Library

    Serna M., Edgar

    2011-01-01

    Maria Sklodowska--Marie Curie--fue pionera en la ciencia de la radiactividad; es mejor conocida como la descubridora de los elementos radiactivos polonio y radio, y como el primer cientifico en ganar dos premios Nobel: Fisica y Quimica...

  6. Structure and Curie temperature of Y2Fe17-xCrx

    Institute of Scientific and Technical Information of China (English)

    HAO; Shiqiang; (

    2003-01-01

    [1]Sun Hong, Coey, J. M. D., Otani, Y. et al., Magnetic properties of a new series of rare-earth iron nitrides: R2Fe17Ny (y~2.6), J. Phys.: Condens. Matter., 1990, 2: 6465-6470.[2]Jacobs, T. H., Buschow, K. H. J., Zhou, G. F. et al., Magnetic interactions in R2Fe17-xAlx compounds (R=Ho, Y), J. Magn. Magn. Mater., 1992,116: 220-230.[3]Gvord, D., Lemaire, R., Magnetic transition and anomalous thermal expansion in R2Fe17 compounds, IEEE Trans. Magn., 1974, 10: 109-113.[4]Gubbens, P. C. M., van der Kraan, A. M., Jacobs, T. N. et al., 57Fe and 169Tm Mossbauer effect and magnetic properties of Tm2Fe15M2 (M=Al, Ga, Si), J. Less-Common Met., 1990,159: 173.[5]Middleton, D. P., Buschow, K. H. J., Magnetic properties of Ce2Fe17-xSix compounds, J. Alloys of Compounds, 1994, 206: L1-L2.[6]Jaswal, S. S., Yelon, W. B., Hadjipanayis, G. C. et al., Electronic and magnetic structures of the rare-earth compounds: R2Fe17Nx, Phys. Rev. Lett., 1991,67(5): 644-647.[7]Sabiryanov, R. F., Jaswal, S. S., Ab initio calculations of the Curie temperature of complex permanent-magnet materials, Phys. Rev. Lett., 1997, 79: 155-158.[8]Chen, N. X., Shen, J., Su, X. P., Theoretical study on the phase stability, site preference, and lattice parameters for Gd(Fe,T)12, J. Phys.: Condens. Matter., 2001, 13: 2727-2736.[9]Chen, N. X., Hao, S. Q., Wu, Y. et al., Phase stability and site preference of Sm(Fe,T)12, J. Magn. Magn. Mater., 2001, 233: 169-180.[10]Carlsson, A. E., Gelatt, C. D., Ehrenreich, H., An ab initio pair potential applied to metals, Philos. Mag. A, 1980, 41: 241-250.[11]Chen, N. X., Chen, Z. D., Wei, Y. C., Multidimensional inverse lattice problem and a uniformly sampled arithmetic Fourier transform, Phys. Rev. E, 1997, 55: R5-R8.[12]Chen, N. X., Ren, G. B., Carlsson-Gelatt-Ehrenreich technique and the Mobius inversion theorem, Phys. Rev. B, 1992, 45: 8177-8180.[13]Chen, N. X., Ge, X. J., Zhang, W. Q., Atomistic analysis of the field

  7. Large magnetization and high Curie temperature in highly disordered nanoscale Fe2CrAl thin films

    Science.gov (United States)

    Dulal, Rajendra P.; Dahal, Bishnu R.; Forbes, Andrew; Pegg, Ian L.; Philip, John

    2017-02-01

    We have successfully grown nanoscale Fe2CrAl thin films on polished Si/SiO2 substrates using an ultra-high vacuum deposition with a base pressure of 9×10-10 Torr. The thickness of thin films ranges from 30 to 100 nm. These films exhibit cubic crystal structure with lattice disorder and display ferromagnetic behavior. The Curie temperature is greater than 400 K, which is much higher than that reported for bulk Fe2CrAl. The magnetic moments of the films varies from 2.5 to 2.8 μB per formula unit, which is larger than the reported bulk values. Thus, the disordered nanoscale Fe2CrAl films exhibit strong Fe-Fe exchange interactions through Fe-Cr-Fe and Fe-Al-Fe layers, resulting in both a large magnetization and a high Curie temperature.

  8. Atomic long-range order effects on Curie temperature and adiabatic spin-wave dynamics in strained Fe-Co alloy films

    Science.gov (United States)

    Schönecker, Stephan; Li, Xiaoqing; Johansson, Börje; Vitos, Levente

    2016-08-01

    The strained Fe-Co alloy in body-centered tetragonal (bct) structure has raised considerable interest due to its giant uniaxial magnetocrystalline anisotropy energy. On the basis of the classical Heisenberg Hamiltonian with ab initio interatomic exchange interactions, we perform a theoretical study of fundamental finite temperature magnetic properties of Fe1 -xCox alloy films as a function of three variables: chemical composition 0.3 ≤x ≤0.8 , bct geometry [a ,c (a )] arising from in-plane strain and associated out-of-plane relaxation, and atomic long-range order (ALRO). The Curie temperatures TC(x ,a ) obtained from Monte Carlo simulations display a competition between a pronounced dependence on tetragonality, strong ferromagnetism in the Co-rich alloy, and the beginning instability of ferromagnetic order in the Fe-rich alloy when c /a →√{2 } . Atomic ordering enhances TC and arises mainly due to different distributions of atoms in neighboring coordination shells rather than altering exchange interactions significantly. We investigate the ordering effect on the shape of the adiabatic spin-wave spectrum for selected pairs (x ,a ) . Our results indicate that long-wavelength acoustic spin-wave excitations show dependencies on x , a , and ALRO similar to those of TC. The directional anisotropy of the spin-wave stiffness d (x ,a ) peaks in narrow ranges of composition and tetragonality. ALRO exhibits a strong effect on d for near equiconcentration Fe-Co. We also discuss our findings in the context of employing Fe-Co as perpendicular magnetic recording medium.

  9. Co{sub x}C nanorod magnets: Highly magnetocrystalline anisotropy with lower Curie temperature for potential applications

    Energy Technology Data Exchange (ETDEWEB)

    El-Gendy, Ahmed A., E-mail: aelgendy@vcu.edu [Department of Chemistry, Virginia Commonwealth University (VCU), Richmond, VA (United States); Nanotechnology and Nanometrology Lab., National Institute for Standards (NIS), Giza (Egypt); Almugaiteeb, Turki [Department of Chemistry, Virginia Commonwealth University (VCU), Richmond, VA (United States); Carpenter, Everett E., E-mail: ecarpenter2@vcu.edu [Department of Chemistry, Virginia Commonwealth University (VCU), Richmond, VA (United States)

    2013-12-15

    Magnetic Co{sub x}C nanorods with larger magnetocrystalline anisotropy of 5×10{sup 5} J/m{sup 3} as well as larger coercivity and lower Curie temperature are introduced. The particles have an average diameter of 8 nm and shows three different magnetic behaviors. The sample shows ferromagnetism up to 400 K, superparamagnetism at temperature >400 K and

  10. Stress-induced large Curie temperature enhancement in Fe(sub 64)Ni(sub 36) Invar alloy.

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, P.; Martinez-Blanco, D.; Perez, M. J.; Blanco, J. A.; Hernando, A.; Laguna-Marco, M. A.; Haskel, D.; Souza-Neto, N. M.; Xmith, R. I.; Marshall, W. G.; Garbarino, G.; Mezouar, M.; Fernandez-Martinez, A.; Chaboy, J.; Fernandez Barquin, L.; Rodriguez Castrillon, J. A.; Moldovan, M.; Garcia Alonso, J. I.; Zhang, J.; Llobet, A.; Jiang, J. S.; Univ. de Oviedo; Inst. de Magnetismo Aplicado; ISIS Facility; ESRF; Univ.Grenoble and CNRS; CSIC-Univ. de Zaragoza; Univ. de Cantabria; LANL

    2009-01-01

    We have succeeded in increasing up to 150 K the Curie temperature in the Fe{sub 64}N{sub 36}6 invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these invar compounds.

  11. Significant increase of Curie temperature and large piezoelectric coefficient in Ba(Ti0.80Zr0.20)O3-0.5(Ba0.70Ca0.30)TiO3 nanofibers

    Science.gov (United States)

    Fu, Bi; Yang, Yaodong; Gao, Kun; Wang, Yaping

    2015-07-01

    Ba(Ti0.80Zr0.20)O3-0.5(Ba0.7Ca0.3)TiO3 (abbreviated as BTZ-0.5BCT) is a piezoelectric ceramic with a high piezoelectric coefficient d33 (˜620 pC N-1) and has been regarded as one of the most promising candidates to replace PZT-based materials (200-710 pC N-1). However, its Curie temperature TC is relatively low (93 °C) limiting its application. In this letter, we found a temperature dependent Raman spectrum in BTZ-0.5BCT nanofibers (NFs), demonstrating a diffused tetragonal-to-cubic phase transition at 300 °C. This means that the TC of the NFs is nearly 207 °C higher than that of the normal bulk material. The increased TC is considered to be associated with the size effect of BTZ-0.5BCT nanoceramic subunits and the nanoporous nature of the fiber, resulting in discontinuous physical properties. The variation of the ferro/piezoelectricity over the fiber surface is attributed to the polycrystalline structure. The d33 (173.32 pm V-1) is improved in terms of the decreased Q factor result in an increase in d33 of 236.54 pm V-1 after polarization. With a high TC and a very large d33, BTZ-0.5BCT NFs are capable of providing electromechanical behavior used in moderate temperatures.

  12. Madame Curie

    CERN Document Server

    Eve, Curie

    1942-01-01

    Marie Curie is a women who changed the face of science for all time, not just because of her discovery of the radioactive element Radium and her work with it, but because of her incredible strides forward in a such a male dominated world as laboratory science at the turn of the 19th century. This is the Madame Curie many people know but here is a biography written by her daughter Eve that shows her human side, in a way that can only be viewed and admired from a family member describing her as a caring mother, devoted and passionate wife. Many of the earliest books, particularly those dating back to the 1900s and before, are now extremely scarce and increasingly expensive.

  13. Extrinsic Curie temperature and spin reorientation changes in Nd{sub 2}Fe{sub 14}B/{alpha}-Fe nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, L.H. [Brookhaven National Lab., Upton, NY (United States); Panchanathan, V. [Magnequench International, Inc., Anderson, IN (United States)

    1998-05-01

    The Curie temperatures and spin reorientation temperatures of a series of four melt-spun nanocomposite materials comprised of Nd{sub 2}Fe{sub 1}4B and varying amounts of {alpha}-Fe were measured using independent techniques. The phase constitution and grain size was assessed with synchrotron x-ray diffraction; the Curie temperatures were measured by differential thermal analysis (DTA) and dc SQUID magnetometry in the temperature range 375 K {le} T {le} 800 K, whereas the spin reorientation transition temperature was determined from ac susceptibility measurements taken in the range 10 K {le} T {le} 300 K. The Curie temperature increases with increasing excess iron content, resulting in a 18 {degree} enhancement over the Curie temperature of pure Nd{sub 2}Fe{sub 14}B for 27 wt% excess {alpha}-Fe. The spin reorientation temperatures are depressed from the single-crystal value by an average of 10 degrees. Both anomalous effects are attributed to intergranular exchange coupling present in the alloys, although the effects of uncompensated stress between the constituent phases cannot be ruled out The experimental results suggest that while the Curie temperature of the Nd{sub 2}Fe{sub 14}B phase may be extrinsically enhanced significantly beyond the bulk value, possibly extending the range of applications of this compound, the anisotropy may be simultaneously lowered, impeding the attainment of high coercivities in these alloys.

  14. Numerical study on the multi-region bio-heat equation to model magnetic fluid hyperthermia (MFH) using low Curie temperature nanoparticles.

    Science.gov (United States)

    Zhang, Chuanqian; Johnson, Duane T; Brazel, Christopher S

    2008-12-01

    This study develops and solves two-dimensional convective-conductive coupled partial differential equations based on Pennes' bio-heat transfer model using low Curie temperature nanoparticles (LCTNPs) to illustrate thermal behavior quantitatively within tumor-normal composite tissue by establishing a multi-region finite difference algorithm. The model combines NEel relaxation and temperature-variant saturation magnetization derived from Brillouin Equation and Curie-Weiss Law. The numerical results indicate that different deposition patterns of LCTNP and boundary conditions directly effect the steady state temperature distribution. Compared with high Curie temperature nanoparticles (HCTNPs), optimized distributions of LCTNPs within tumorous tissue can be used to control the temperature increase in tumors for hyperthermia treatment using an external magnetic field while healthy tissue surrounding a tumor can be kept closer to normal body tissue, reducing the side effects observed in whole body and regional hyperthermia therapy.

  15. Strongly enhanced Curie temperature in carbon-doped Mn{sub 5}Ge{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Gajdzik, M.; Suergers, C. E-mail: christoph.suergers@physik.uni-karlsruhe.de; Kelemen, M.T.; Loehneysen, H. von

    2000-11-01

    The structural and magnetic properties of Mn{sub 5}Ge{sub 3}C{sub x} films prepared at elevated substrate temperatures T{sub S} are investigated. In particular, films with x{>=}0.5 and T{sub S}=680 K exhibit a strongly enhanced Curie temperature T{sub C}=445 K compared to bulk Mn{sub 5}Ge{sub 3} with T{sub C}=304 K while at the same time the average Mn moment decreases from 2.6 to 1 {mu}{sub B}. Structural analysis of these films suggests that the carbon is interstitially incorporated into the voids of Mn octahedra of the hexagonal Mn{sub 5}Si{sub 3}-type structure giving rise to a lattice compression. The enhanced ferromagnetic stability in connection with the lattice compression is interpreted in terms of an Mn-Mn interaction mediated by C based on a change in the electronic structure.

  16. Low-temperature dynamics of the Curie-Weiss Model: Periodic orbits, multiple histories, and loss of Gibbsianness

    CERN Document Server

    Ermolaev, Victor

    2010-01-01

    We consider the Curie-Weiss model at a given initial temperature in vanishing external field evolving under a Glauber spin-flip dynamics corresponding to a possibly different temperature. We study the limiting conditional probabilities and their continuity properties and discuss their set of points of discontinuity (bad points). We provide a complete analysis of the transition between Gibbsian and non-Gibbsian behavior as a function of time, extending earlier work for the case of independent spin-flip dynamics. For initial temperature bigger than one we prove that the time-evolved measure stays Gibbs forever, for any (possibly low) temperature of the dynamics. In the regime of heating to low-temperatures from even lower temperatures, when the initial temperature is smaller than the temperature of the dynamics, and smaller than 1, we prove that the time-evolved measure is Gibbs initially and becomes non-Gibbs after a sharp transition time. We find this regime is further divided into a region where only symmetr...

  17. Stress-induced Curie temperature increase in the Fe{sub 64}Ni{sub 36} invar alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, Pedro; Martinez-Blanco, David; Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo (Spain); Boada, Roberto; Chaboy, Jesus [ICMA and Departamento de Fisica de la Materia Condensada, CSIC - Universidad de Zaragoza (Spain); Fernandez-Martinez, Alejandro [LGIT, University of Grenoble and CNRS, Maison des Geosciences, Grenoble (France); Institut Laue-Langevin, Grenoble (France); Garbarino, Gaston; Castro, German R.; Mezouar, Mohamed [European Synchrotron Radiation Facility (ESRF), Grenoble (France); Smith, Ronald I. [ISIS Facility, RAL, Chilton, Didcot, Oxon (United Kingdom); Alonso, J.I.G. [Department of Physical and Analytical Chemistry, University of Oviedo (Spain); Hernando, Antonio [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC, Madrid (Spain)

    2009-05-15

    Structural and magnetic changes on invar Fe{sub 64}Ni{sub 36} alloy (T{sub C}=500 K) produced by mechanical milling followed by heating up to 1073 K, were investigated by neutron diffraction, magnetization measurements, X-ray diffraction under high pressures and X-ray absorption at both Fe and Ni K-edges. We argue that the strain induced in the Fe{sub 64}Ni{sub 36} material after this treatment mainly affects the Fe sites due to the magnetovolume coupling, the most notorious feature being the increase of the Curie temperature ({delta}T{sub C}=70 K). (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Curie temperature of GaMnN and GaMnAs from LDA-SIC electronic structure calculations

    Energy Technology Data Exchange (ETDEWEB)

    Toyoda, Masayuki; Sato, Kazunori; Katayama-Yoshida, Hiroshi [Department of Computational Nanomaterials Design, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Akai, Hisazumi [Department of Physics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)

    2006-07-01

    We present the electronic structures, magnetic exchange interactions and Curie temperature (T{sub C}) of GaMnN and GaMnAs calculated by self-interaction-corrected local-density approximation (LDA-SIC). In GaMnAs, the LDA-SIC results of T{sub C} do not differ so much from the LDA results. Both the LDA and LDA-SIC values are in a good agreement with the experimental data. In GaMnN, on the other hand, the ferromagnetic exchange interactions are enhanced due to the suppression of antiferromagnetic super-exchange interaction, resulting in T{sub C} higher than the LDA results. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Thickness dependent Curie temperature and power-law behavior of layering transitions in ferromagnetic classical and quantum thin films described by Ising, XY and Heisenberg models

    Energy Technology Data Exchange (ETDEWEB)

    Yüksel, Yusuf, E-mail: yusuf.yuksel@deu.edu.tr; Akıncı, Ümit

    2015-04-01

    Ferromagnetic–paramagnetic phase transitions in classical and quantum thin films have been studied up to 50 mono-layers using effective field theory with two-site cluster approximation. Variation of the Curie temperature as a function of film thickness has been examined. The relative shift of the Curie temperature from the corresponding bulk value has been investigated in terms of the shift exponent λ. We have found that shift exponent λ clearly depends on the strength of the ferromagnetic exchange coupling of the surface. Moreover, we have not observed any significant difference between classical and quantum exponents for a particular model.

  20. Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiawei; Huo, Juntao; Chang, Chuntao, E-mail: ctchang@nimte.ac.cn, E-mail: dujun@nimte.ac.cn; Du, Juan, E-mail: ctchang@nimte.ac.cn, E-mail: dujun@nimte.ac.cn; Man, Qikui; Wang, Xinmin; Li, Run-Wei [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Law, Jiayan [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden)

    2014-08-14

    The effects of heavy rare earth (RE) additions on the Curie temperature (T{sub C}) and magnetocaloric effect of the Fe-RE-B-Nb (RE = Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune T{sub C} in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (ΔS{sub M}) and refrigerant capacity (RC) of the alloys. The observed values of ΔS{sub M} and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd{sub 5}Ge{sub 1.9}Si{sub 2}Fe{sub 0.1}. The tunable T{sub C} and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.

  1. Recent Developments on High Curie Temperature PIN-PMN-PT Ferroelectric Crystals.

    Science.gov (United States)

    Zhang, Shujun; Li, Fei; Sherlock, Nevin P; Luo, Jun; Lee, Hyeong Jae; Xia, Ru; Meyer, Richard J; Hackenberger, Wesley; Shrout, Thomas R

    2011-03-01

    Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PIN-PMN-PT) ferroelectric crystals attracted extensive attentions in last couple years, due to their higher usage temperatures range (> 30°C) and coercive fields (~5kV/cm), meanwhile maintaining similar electromechanical couplings (k(33)> 90%) and piezoelectric coefficients (d(33)~1500pC/N), when compared to their binary counterpart Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3). In this article, we reviewed recent developments on the PIN-PMN-PT single crystals, including the Bridgman crystal growth, dielectric, electromechanical, piezoelectric and ferroelectric behaviors as function of temperature and dc bias. Mechanical quality factor Q was studied as function of orientation and phase. Of particular interest is the dynamic strain, which related to the Q and d(33), was found to be improved when compared to binary system, exhibiting the potential usage of PIN-PMN-PT in high power application. Furthermore, PIN-PMN-PT crystals exhibit improved thickness dependent properties, due to their small domain size, being on the order of 1μm. Finally, the manganese acceptor dopant in the ternary crystals was investigated and discussed briefly in this paper.

  2. Low temperature spark plasma sintering of TC4/HA composites

    Institute of Scientific and Technical Information of China (English)

    Huiliang Shao; Lei Cao; Daqian Sun; Zhankui Zhao

    2016-01-01

    Ti6Al4V/hydroxyapatite composites (TC4/HA) have been prepared by high energy ball milling and low temperature spark plasma sintering at 600 °C, 550 °C, 500 °C and 450 °C, respectively. The sintering temperature of the composites was sharply decreased as the result of the activation and surficial modification effects induced from high energy ball milling. The decomposition and reaction of hydro-xyapatite was successfully avoided, which offers the composites superior biocompatibility. The hydro-xyapatite in the composites was distributed in gap uniformly, and formed an ideal network structure. The lowest hardness, compressive strength and Young's modulus of the composites satisfy the requirements of human bone.

  3. Effect of pressure on the Curie temperature of Mn{sub 2}RuSn and Mn{sub 2}PdSn

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Y., E-mail: adachy@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, Yonezawa 992-8510 (Japan); Watanabe, T. [Faculty of Engineering, Yamagata University, Yonezawa 992-8510 (Japan); Kanomata, T. [Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537 (Japan); Research Institute for Engineering and Technology, Tohoku Gakuin University, 985-8537 (Japan); Hayasaka, M.; Endo, K. [Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537 (Japan); Nishihara, H. [Faculty of Science and Technology, Ryukoku University, Otsu 520-2194 (Japan); Xu, X.; Kainuma, R. [Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2017-04-15

    Effect of pressure on the Curie temperature T{sub C} of the Mn-rich Heusler alloys Mn{sub 2}RuSn and Mn{sub 2}PdSn has been investigated by measuring the temperature dependence of initial permeability at various pressures up to 10 kbar. It was found that the Curie temperatures of Mn{sub 2}RuSn and Mn{sub 2}PdSn decrease with increasing pressure. The pressure derivatives of T{sub C} were estimated to be −0.59 K/kbar for Mn{sub 2}RuSn and −0.80 K/kbar for Mn{sub 2}PdSn. On the basis of the experimental results, the relationship between the magnetic transition temperature and the Mn-Mn distance is discussed.

  4. Engineering of the Curie temperature of epitaxial Sr1-xBaxTiO3 films via strain

    Science.gov (United States)

    Dai, Y.; Schubert, J.; Hollmann, E.; Mussler, G.; Wördenweber, R.

    2016-09-01

    The impact of strain on the structural and electrical properties of epitaxial Sr1-xBaxTiO3 films grown on single crystalline DyScO3 (110), TbScO3 (110), and GdScO3 (110) substrates is presented. X-ray diffraction measurements demonstrate that all films are grown epitaxially. The tensile in-plane strain is only partially compensated by a contraction of the out-of-plane lattice parameter. As a result, the volume of the unit cell of the Sr1-xBaxTiO3 film increases due to the tensile strain, and the resulting Poisson ratio of the film is ν ≈ 0.33, which is larger than but still close to the literature values of ν ≈ 0.23 for unstrained defect-free SrTiO3. The Curie temperature derived from the temperature dependence of the in-plane dielectric response leads to a strain-temperature phase diagram for the epitaxial Sr1-xBaxTiO3 films. The experimental data show a deviation from the linear dependence predicted by the Landau thermodynamic theory for large strain (>1.2%). However, using the equilibrium thermodynamic analysis, we can demonstrate that this deviation arises from the relaxation of the strain due to defect formation in the film. The result reveals that in addition to the nominal misfit strain, the defect formation strongly affects the effective strain and, thus, the dielectric response of epitaxially grown ferroelectric films.

  5. Ultra-high Curie temperature (>800 °C) low sintering temperature Bi2(1-x)La2xWO6 piezoelectric material for the applications of seafloor hydrothermal vents detection

    Science.gov (United States)

    Liao, Qingwei; An, Zhao; Huang, Haining; Fang, Mingwei; Chen, Zhongjun; Peng, Shasha; Li, Kun

    2016-10-01

    Searching low sintering temperature material with ultra-high Curie temperature (>800 °C) is urgent to seafloor hydrothermal vents detection. Bi2WO6, as the simplest member of the Aurivillius family was improved to possess ultra-high Curie temperature and ultra-high depolarization temperature by experiment at first time. The crystal structure was determined by ab initio and Rietveld refinement calculations. The symmetry group of ultra-high Curie temperature Bi2WO6 is Aba2 (41). The Curie temperatures of Bi2(1-x)La2xWO6 (x = 0, 0.005, 0.01, 0.02, 0.04) with increasing x are 952 °C, 1008 °C, 905 °C, 853 °C, 822 °C, respectively, and depolarization temperatures of them are around 915 °C, 905 °C, 880 °C, 800 °C, and 725 °C, respectively. The typical properties are as follows: Curie temperature T c = 905 °C, depolarization temperature T d = 880 °C, mechanical quality factor Q m = 621.8, d 33 = 17 pC/N, K 33 = 82.01, tanδ = 0.19 × 10-2 with x value of 0.01.

  6. Magnetization and magnetic entropy change of a three-dimensional isotropic ferromagnet near the Curie temperature in the random phase approximation

    Energy Technology Data Exchange (ETDEWEB)

    Kokorina, E.E., E-mail: kokorina@iep.uran.ru [Institute of Electrophysics, Russian Academy of Sciences-Ural Division, 620016 Ekaterinburg (Russian Federation); Medvedev, M.V. [Institute of Electrophysics, Russian Academy of Sciences-Ural Division, 620016 Ekaterinburg (Russian Federation); Department of Theoretical Physics, Ural Federal University, 620083 Ekaterinburg (Russian Federation)

    2013-05-01

    The behavior of a three-dimensional isotropic Heisenberg ferromagnet in the presence of a magnetic field H is investigated in the random phase approximation (RPA) near the Curie temperature T{sub c}. It is shown that the magnetization M at the Curie temperature T{sub c} is described by the law M(T=T{sub c})∼H{sup 1/5} and the initial magnetic susceptibility χ{sub 0} at temperatures T≥T{sub c} is given by χ{sub 0}(T≥T{sub c})∼(T−T{sub c}){sup −2}. It means that in the RPA the critical exponents for a three-dimensional Heisenberg ferromagnet coincide with the critical exponents for the Berlin-Kac spherical model of a ferromagnet rather than with the critical exponents of the mean field approximation (MFA). Hence it follows as well that, when a magnetic field H is risen from H=0 to H=H{sub a}, the magnetic entropy S{sub M} will be decreased as ΔS{sub M}(T=T{sub c})∼−H{sub a}{sup 4/5} at the Curie temperature T{sub c} and as ΔS{sub M}(T>T{sub c})∼−(T−T{sub c}){sup −3}H{sub a}{sup 2} at temperatures T>T{sub c}.

  7. Structure, electrical properties of Bi(Fe, Co)O{sub 3}-BaTiO{sub 3} piezoelectric ceramics with improved Curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Changrong, E-mail: zcr750320@yahoo.com.cn [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Cen Zhenyong [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Yang Huabin [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Zhou Qin [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Li Weizhou [School of Materials Science and Engineering, Guangxi University, Nanning, Guangxi 530004 (China); Yuan Changlai; Wang Hua [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China)

    2013-02-01

    Dense (1-y)BiFe{sub 1-x}Co{sub x}O{sub 3}-yBaTiO{sub 3} (BFC-BTx, y=0.29, x=0-0.012) high-temperature lead-free ceramics were prepared by the conventional oxide-mixed method and the effects of BiCoO{sub 3} modification on microstructural, electrical properties and their Curie temperatures were investigated. The solid solutions show a single phase perovskite structure, and the content of BiCoO{sub 3} has a significant effect on the microstructure of ceramics. The BFC-BTx ceramics exhibit improved Curie temperature T{sub c}, together with increased piezoelectric properties. In particular, x=0.6% BFC-BTx ceramics, with a Curie temperature, T{sub c}, of {approx}488 Degree-Sign C, show optimum piezoelectric properties of d{sub 33}=167 pC/N, k{sub p}=0.32. The combination of good piezoelectric properties and high T{sub c} makes these ceramics suitable for elevated temperature piezoelectric devices.

  8. Structural and magnetic properties of GeMn layers; High Curie temperature ferromagnetism induced by self organized GeMn nano-columns

    Energy Technology Data Exchange (ETDEWEB)

    Devillers, T.; Jamet, M.; Barski, A.; Poydenot, V.; Dujardin, R.; Bayle Guillemaud, P.; Bellet Amalric, E.; Mattana, R. [Departement de Recherche Fondamentale sur la Matiere Condensee, Service de Physique des Materiaux et Microstructures, CEA Grenoble, 17 avenue des Martyrs, 38054 Grenoble Cedex (France); Rothman, J. [Laboratoire d' Electronique de Technologie de l' Information, Laboratoire Infrarouge, CEA Grenoble, 17 avenue des Martyrs, 38054 Grenoble Cedex (France); Cibert, J. [Laboratoire Louis Neel, CNRS, BP166, 38042 Grenoble Cedex 9 (France); Tatarenko, S. [Laboratoire de Spectrometrie Physique, BP 87, 38402 Saint-Martin d' Heres (France)

    2007-01-15

    In this paper we report on the structural and magnetic properties of GeMn layers grown on Ge(001). We show that for the optimized Mn concentration (6%) and for optimized growth temperature (close to 130 C), GeMn samples exhibit a high Curie temperature (higher than 400 K) and Anomalous Hall Effect up to room temperature. Our GeMn layers grown at low temperature (70 C to 130 C) are composed of vertical Mn-rich nano-columns. Samples grown at temperatures higher than 130 C contain GeMn nanoclusters. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. CURIE: Cubesat Radio Interferometry Experiment

    Science.gov (United States)

    Sundkvist, D. J.; Saint-Hilaire, P.; Bain, H. M.; Bale, S. D.; Bonnell, J. W.; Hurford, G. J.; Maruca, B.; Martinez Oliveros, J. C.; Pulupa, M.

    2016-12-01

    The CUbesat Radio Interferometry Experiment (CURIE) is a proposed two-element radio interferometer, based on proven and developed digital radio receivers and designed to fit within a Cubesat platform. CURIE will launch as a 6U Cubesat and then separate into two 3U Cubesats once in orbit. CURIE measures radio waves from 0.1-19MHz, which must be measured from space, as those frequencies fall below the cutoff imposed by Earth's ionosphere. The principal science objective for CURIE is to use radio interferometry to study radio burst emissions from solar eruptive events such as flares and coronal mass ejections (CMEs) in the inner heliosphere, providing observations important for our understanding of the heliospheric space weather environment. The influence of space weather can be felt at Earth and other planets, as radiation levels increase and lead to auroral activity and geomagnetic effects. CURIE will be able to determine the location and size of radio burst source regions and then to track their movement outward from the Sun. In addition to the primary objective CURIE will measure the gradients of the local ionospheric density and electron temperature on the spatial scale of a few kilometers, as well as create an improved map of the radio sky at these unexplored frequencies. A space based radio interferometry observatory has long been envisioned, in orbit around the Earth or the Moon, or on the far side of the Moon. Beyond its important science objectives, CURIE will prove that the concept of a dedicated space-based interferometer can be realized by using relatively cheap Cubesats. CURIE will therefore not only provide new important science results but also serve as a pathfinder in the development of new space-based radio observation techniques for helio- and astro-physics.

  10. Study by neutron diffusion of magnetic fluctuations in iron in the curie temperature region; Etude des fluctuations d'aimantation dans le fer au voisinage de la temperature de curie par diffusion des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ericson-Galula, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-12-15

    The critical diffusion of neutrons in iron is due to the magnetisation fluctuations which occur in ferromagnetic substances in the neighbourhood of the Curie temperature. The fluctuations can be described in correlation terms; a correlation function {gamma}{sub R{sub vector}} (t) is defined, {gamma}{sub R{sub vector}} (t) = mean value of the scalar product of a reference spin and a spin situated at a distance (R) from the first and considered at the instant t. In chapter I we recall the generalities on neutron diffusion cross-sections; a brief summary is given of the theory of VAN HOVE, who has shown that the magnetic diffusion cross section of neutrons is the Fourier transformation of the correlation function. In chapter Il we study the spatial dependence of the correlation function, assumed to be independent of time. It can then be characterised by two parameters K{sub 1} and r{sub 1}, by means of which the range and intensity of the correlations can be calculated respectively. After setting out the principle of the measurement of these parameters, we shall describe the experimental apparatus. The experimental values obtained are in good agreement with the calculations, and the agreement is better if it is supposed that the second and not the first neighbours of an iron atom are magnetically active, as proposed by Neel. In chapter III we study the evolution with time of the correlation function; this evolution is characterised by a parameter {lambda} depending on the temperature, which occurs in the diffusion equation obeyed by the magnetisation fluctuations: {delta}M{sub vector}/{delta}t = {lambda} {nabla}{sup 2} M{sub vector}. The principle of the measurement of {lambda} is given, after which the modifications carried out on the experimental apparatus mentioned in chapter II are described. The results obtained are then discussed and compared with the theoretical forecasts of De Gennes, mode by using the

  11. Tunable Curie temperature around room temperature and magnetocaloric effect in ternary Ce-Fe-B amorphous ribbons

    Science.gov (United States)

    Li, Zhu-bai; Zhang, Le-le; Zhang, Xue-feng; Li, Yong-feng; Zhao, Qian; Zhao, Tong-yun; Shen, Bao-gen

    2017-01-01

    Ce13-x Fe81+x B6 (x  =  0, 0.5, 1, 1.5, and 2) amorphous magnets were prepared by melt-spinning method. These magnets are magnetically soft at low temperature, and undergo a second-order phase transition from ferromagnetic to paramagnetic state near room temperature with a broad temperature span. The phase-transition temperature is tunable by the variation of the Ce/Fe atomic ratio, which is mainly due to the change of the coordination number of Fe atoms in these ternary Ce-Fe-B amorphous magnets. Though the entropy change is low, the refrigeration capacities are in the ranges of 116-150 J kg-1 and 319-420 J kg-1, respectively, for the magnetic field changes of 0-2 T and 0-5 T, which is comparable with those of conventional magnetic materials for room-temperature refrigeration. Given the low cost of Fe and Ce, Ce-Fe-B amorphous magnets are attractive magnetic refrigerant candidates.

  12. Origin of the high Neel temperature in SrTcO3

    OpenAIRE

    Mravlje, J.; Aichhorn, M; Georges, A.

    2011-01-01

    We investigate the origin of the high Neel temperature recently found in Tc perovskites. The electronic structure in the magnetic state of SrTcO3 and its 3d analogue SrMnO3 is calculated within a framework combining band-structure and many-body methods. In agreement with experiment, the Neel temperature of SrTcO3 is found to be four times larger than that of SrMnO3. We show that this is because the Tc-compound lies on the verge of the itinerant-to-localized transition, and also has a larger b...

  13. Significantly enhanced piezoelectricity in low-temperature sintered Aurivillius-type ceramics with ultrahigh Curie temperature of 800 °C

    Science.gov (United States)

    Cai, Kai; Huang, Chengcheng; Guo, Dong

    2017-04-01

    We report an Aurivillius-type piezoelectric ceramic (Ca1‑2x (LiCe) x Bi4Ti3.99Zn0.01O15) that has an ultrahigh Curie temperature (T c) around 800 °C and a significantly enhanced piezoelectric coefficient (d 33), comparable to that of textured ceramics fabricated using the complicated templating method. Surprisingly, the highest d 33 of 26 pC/N was achieved at an unexpectedly low sintering temperature (T s) of only 920 °C (~200 °C lower than usual) despite the non-ideal density. Study of different synthesized samples indicates that a relatively low T s is crucial for suppressing Bi evaporation and abnormal grain growth, which are indispensable for high resistivity and effective poling due to decreased carrier density and restricted anisotropic conduction. Because the layered structure is sensitive to lattice defects, controlled Bi loss is considered to be crucial for maintaining structural order and spontaneous polarization. This low-T s system is very promising for practical applications due to its high piezoelectricity, low cost and high reproducibility. Contrary to our usual understanding, the results reveal that a delicate balance of density, Bi loss and grain morphology achieved by adjusting the sintering temperature is crucial for the enhancing performance in Aurivillius-type high-T c ceramics.

  14. Debye temperature, thermal expansion, and heat capacity of TcC up to 100 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Song, T., E-mail: songting@mail.lzjtu.cn [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); School of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Ma, Q. [School of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Tian, J.H. [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Liu, X.B. [School of Physics and Information Science, Tianshui Normal University, Tianshui 741000 (China); Ouyang, Y.H.; Zhang, C.L.; Su, W.F. [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China)

    2015-01-15

    Highlights: • A number of thermodynamic properties of rocksalt TcC are investigated for the first time. • The quasi-harmonic Debye model is applied to take into account the thermal effect. • The pressure and temperature up to about 100 GPa and 3000 K, respectively. - Abstract: Debye temperature, thermal expansion coefficient, and heat capacity of ideal stoichiometric TcC in the rocksalt structure have been studied systematically by using ab initio plane-wave pseudopotential density functional theory method within the generalized gradient approximation. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the dependences of Debye temperature, thermal expansion coefficient, constant-volume heat capacity, and constant-pressure heat capacity on pressure and temperature are successfully predicted. All the thermodynamic properties of TcC with rocksalt phase have been predicted in the entire temperature range from 300 to 3000 K and pressure up to 100 GPa.

  15. Forearc structure in the Lesser Antilles inferred from depth to the Curie temperature and thermo-mechanical simulations

    Science.gov (United States)

    Gailler, Lydie; Arcay, Diane; Münch, Philippe; Martelet, Guillaume; Thinon, Isabelle; Lebrun, Jean-Frédéric

    2017-06-01

    Imaging deep active volcanic areas remains a challenge in our understanding of their activity and evolution, especially in subduction zones. Study of magnetic anomalies is appropriate to access such dynamics in depth. The magnetic anomaly pattern of the Lesser Antilles Arc (LAA) subduction is studied through Curie Point Depth (CPD), interpreted as the depth of the 580 °C isotherm, and developed to better assess the deep thermal structure of the arc. The depth of the estimated CPD exhibits a complex topography. Keeping in mind the overall uncertainty associated with this method, a main doming is evidenced below the Guadeloupe archipelago. Its apex is shifted towards the ancient arc, suggesting a very hot state of the fore-arc/arc domain. To better understand the LAA thermal state, we perform 2D thermo-mechanical simulations of the subduction zone. Recalling that magnetite is a serpentinization by-product, we simulate water transfer triggered by slab dehydration to test the assumption of fore-arc serpentinization suggested by the positive magnetic anomaly in the vicinity of the Guadeloupe archipelago. In this area, the subduction-induced arc lithosphere hydration and related weakening trigger a fast heating of the upper plate by basal convective removal. This process of fast arc lithosphere thinning may apply where simultaneously the volcanic arc is split in two and normal convergence is high enough. As serpentinization strongly decreases P-wave velocity, we propose a new interpretation of a published seismic profile below Guadeloupe. The seismic layer previously interpreted as the arc lower crust may rather be a layer of serpentinized mantle, as supported by spatial correlations between gravimetric and magnetic anomalies. Consequently, at the scale of Guadeloupe Island, the fore-arc Moho would be shallower than initially assumed, with a dome shape more consistent with both the extensive deformation active since the Oligocene in the inner fore-arc and the CPD doming.

  16. Increasing the Curie temperature of Ca{sub 2}FeMoO{sub 6} double perovskite by introducing near-neighbour antiferromagnetic interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rubi, D [Institut de Ciencia de Materials de Barcelona, CSIC, Campus UAB, 08193, Bellaterra (Spain); Frontera, C [Institut de Ciencia de Materials de Barcelona, CSIC, Campus UAB, 08193, Bellaterra (Spain); Roig, A [Institut de Ciencia de Materials de Barcelona, CSIC, Campus UAB, 08193, Bellaterra (Spain); Nogues, J [Institut Catala de Recerca i Estudis Avancats (ICREA), 08193, Bellaterra, Catalunya (Spain); Munoz, J S [Departament de Fisica, Universitat Autonoma de Barcelona, 08193, Bellaterra, Catalunya (Spain); Fontcuberta, J [Institut de Ciencia de Materials de Barcelona, CSIC, Campus UAB, 08193, Bellaterra (Spain)

    2005-12-21

    We report on the magnetic, magnetotransport and structural characterization of (Ca{sub 1-y}Nd{sub y}){sub 2}Fe{sub 1+x}Mo{sub 1-x}O{sub 6} (x<0.5) ferromagnetic double perovskites. It is found that the presence of an excess (x>0) of Fe ions in the metallic sublattice produces a remarkable increase, by more than 90 K, of the Curie temperature. Moessbauer spectroscopy data indicate a reinforcement of the magnetic interactions. We argue that this dramatic enhancement of the ferromagnetic order is due to the strong antiferromagnetic superexchange coupling between near-neighbour Fe-Fe occupying regular and antisite positions in the structure. Moreover, the results indicate that the excess of magnetic ions (Fe) is essential to overcome the dilution effects caused by antisite defects.

  17. Enhanced temperature stability and quality factor with Hf substitution for Sn and MnO2 doping of (Ba0.97Ca0.03)(Ti0.96Sn0.04)O3 lead-free piezoelectric ceramics with high Curie temperature

    Science.gov (United States)

    Tsai, Cheng-Che; Chao, Wei-Hsiang; Chu, Sheng-Yuan; Hong, Cheng-Shong; Weng, Chung-Ming; Su, Hsiu-Hsien

    2016-12-01

    In this work, the process of two-stage modifications for (Ba0.97Ca0.03)(Ti0.96Sn0.04-xHfx)O3 (BCTS4-100xH100x) ceramics was studied. The trade-off composition was obtained by Hf substitution for Sn and MnO2 doping (two-stage modification) which improves the temperature stability and piezoelectric properties. The phase structure ratio, microstructure, and dielectric, piezoelectric, ferroelectric, and temperature stability properties were systematically investigated. Results showed that BCTS4-100xH100x piezoelectric ceramics with x=0.035 had a relatively high Curie temperature (TC) of about 112 °C, a piezoelectric charge constant (d33) of 313 pC/N, an electromechanical coupling factor (kp) of 0.49, a mechanical quality factor (Qm) of 122, and a remnant polarization (Pr) of 19 μ C /cm2 . In addition, the temperature stability of the resonant frequency (fr), kp, and aging d33 could be tuned via Hf content. Good piezoelectric temperature stability (up to 110 °C) was found with x =0.035. BCTS0.5H3.5 + a mol% Mn (BCTSH + a Mn) piezoelectric ceramics with a = 2 had a high TC of about 123 °C, kp ˜ 0.39, d33 ˜ 230 pC/N, Qm ˜ 341, and high temperature stability due to the produced oxygen vacancies. This mechanism can be depicted using the complex impedance analysis associated with a valence compensation model on electric properties. Two-stage modification for lead-free (Ba0.97Ca0.03)(Ti0.96Sn0.04)O3 ceramics suitably adjusts the compositions for applications in piezoelectric motors and actuators.

  18. Enhanced temperature stability and quality factor with Hf substitution for Sn and MnO2 doping of (Ba0.97Ca0.03(Ti0.96Sn0.04O3 lead-free piezoelectric ceramics with high Curie temperature

    Directory of Open Access Journals (Sweden)

    Cheng-Che Tsai

    2016-12-01

    Full Text Available In this work, the process of two-stage modifications for (Ba0.97Ca0.03(Ti0.96Sn0.04-xHfxO3 (BCTS4-100xH100x ceramics was studied. The trade-off composition was obtained by Hf substitution for Sn and MnO2 doping (two-stage modification which improves the temperature stability and piezoelectric properties. The phase structure ratio, microstructure, and dielectric, piezoelectric, ferroelectric, and temperature stability properties were systematically investigated. Results showed that BCTS4-100xH100x piezoelectric ceramics with x=0.035 had a relatively high Curie temperature (TC of about 112 °C, a piezoelectric charge constant (d33 of 313 pC/N, an electromechanical coupling factor (kp of 0.49, a mechanical quality factor (Qm of 122, and a remnant polarization (Pr of 19μC/cm2. In addition, the temperature stability of the resonant frequency (fr, kp, and aging d33 could be tuned via Hf content. Good piezoelectric temperature stability (up to 110 °C was found with x =0.035. BCTS0.5H3.5 + a mol% Mn (BCTSH + a Mn piezoelectric ceramics with a = 2 had a high TC of about 123 °C, kp ∼ 0.39, d33 ∼ 230 pC/N, Qm ∼ 341, and high temperature stability due to the produced oxygen vacancies. This mechanism can be depicted using the complex impedance analysis associated with a valence compensation model on electric properties. Two-stage modification for lead-free (Ba0.97Ca0.03(Ti0.96Sn0.04O3 ceramics suitably adjusts the compositions for applications in piezoelectric motors and actuators.

  19. Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Peng Dengfeng [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Wang Xusheng; Yao Xi [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xu Chaonan [National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Lin Jian; Sun Tiantuo [College of Material Science and Engineering, Tongji University, 4800 Cao' an Highway, Shanghai 201804 (China)

    2012-05-15

    Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  20. Pierre y Marie Curie

    OpenAIRE

    Guevara, Juan de Dios; Facultad de Farmacia y Bioquímica de la Universidad Nacional Mayor de San Marcos, Lima, Perú.

    2014-01-01

    Pocas veces se encuentran dos vidas tan profundamente identificadas como las de Pierre Curie y María Sklodowska.Pierre Curie, nació en París el 15 de mayo de 1859; realiza sus estudios preparatorios privadamente, hasta que a los 16 años aprueba su bachillerato, para seguir luego sus estudios en la Facultad de Ciencias donde obtiene su licenciatura en Física en 1877. Su amor a las ciencias naturales parece haberlo adquirido de su padre, Eugenio, con quien realiza sus primeras experiencias. Con...

  1. Effect of Mn-site vacancies on the magnetic entropy change and the Curie temperature of La0.67Ca0.33Mn1-xO3 perovskite

    DEFF Research Database (Denmark)

    Chen, Wei; Nie, L.Y.; Xu, Zhao;

    2006-01-01

    Single-phase polycrystalline samples of La0.67Ca0.33Mn1-xO3 (x = 0.00, 0.02, 0.04, 0.06) have been prepared using the sol-gel method. The structure, magnetocaloric properties and the Curie temperature of the samples with different Mn vacancy concentrations have been investigated. The experimental...

  2. High Curie temperature and enhanced magnetoelectric properties of the laminated Li0.058(Na0.535K0.48)0.942NbO3/Co0.6 Zn0.4Fe1.7Mn0.3O4 composites

    Science.gov (United States)

    Yang, Haibo; Zhang, Jintao; Lin, Ying; Wang, Tong

    2017-03-01

    Laminated magnetoelectric composites of Li0.058(Na0.535K0.48)0.942NbO3 (LKNN)/Co0.6Zn0.4Fe1.7Mn0.3O4 (CZFM) prepared by the conventional solid-state sintering method were investigated for their dielectric, magnetic, and magnetoelectric properties. The microstructure of the laminated composites indicates that the LKNN phase and CZFM phase can coexist in the composites. Compared with the particulate magnetoelectric composites, the laminated composites have better piezoelectric and magnetoelectric properties due to their higher resistances and lower leakage currents. The magnetoelectric behaviors lie on the relative mass ratio of LKNN phase and CZFM phase. The laminated composites possess a high Curie temperature (TC) of 463 °C, and the largest ME coefficient of 285 mV/cm Oe, which is the highest value for the lead-free bulk ceramic magnetoelectric composites so far.

  3. Temperature Dependence of Growth Mechanism for Nanoscale High Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    Wu-Ming Chen; Mustafa Yavuz; Jian-Xun Jin

    2008-01-01

    The growth mechanisms of high temper- ature Yttrium- and Bismuth-based-superconductors were investigated at nanoscale. We started with studying the growth relationships among the three phases of Bi-2201, Bi-2212, and Bi-2233, and then extended to another growth mechanism of Bi-2223 and the growth of yttrium-based high-temperature nanosupercon- ductors (nano-YBCO). A time dependence of growth experiment was performed. In this experiment, the Bi-based superconductors grew within different sintering periods, and its three phases were determined by X-ray diffraction. And then, a time dependence of growth model was suggested to explain the experimental facts. With this model, governing equations were derived to quantitatively describe the growth and decomposition mechanisms during sintering period. The results calculated from the derived equations were well in agreement with the experimental data. We also suggested an alternative growth mechanism for the Bi-2223 phase, which was supported by an observation of transmission electron microscopy (TEM). The nano-YBCO also grew, and their orthorhombic crystal structures were determined by the TEM. The superconducting properties of Bi-2223 were investigated by the measurements of ac magnetic susceptibility. It is expected that the derived equations will fit the alter- native experimental growth mechanism of the Bi-2223 phase and the nano-YBCO growth mechanism, too.

  4. Tuning the Curie temperature of L1{sub 0} ordered FePt thin films through site-specific substitution of Rh

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dongbin, E-mail: dongbin.xu@seagate.com [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, National University of Singapore, Singapore 117576 (Singapore); Sun, Cheng-Jun, E-mail: cjsun@aps.anl.gov, E-mail: msecgm@nus.edu.sg; Heald, Steve M. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Chen, Jing-Sheng; Chow, Gan Moog, E-mail: cjsun@aps.anl.gov, E-mail: msecgm@nus.edu.sg [Department of Materials Science and Engineering, National University of Singapore, Singapore 117576 (Singapore); Zhou, Tie-Jun [Data Storage Institute, Agency for Science, Technology and Research (A-STAR), Singapore 117608 (Singapore); Bergman, Anders; Sanyal, Biplab [Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala (Sweden)

    2014-10-14

    In structurally ordered magnetic thin films, the Curie temperature (T{sub C}) of ferromagnetic films depends on the exchange integral of the short range ordered neighboring atoms. The exchange integral may be adjusted by controlling the elemental substitutional concentration at the lattice site of interest. We show how to control the T{sub C} in high anisotropy L1{sub 0} Fe{sub 50}Pt{sub 50} magnetic thin films by substituting Rh into the Pt site. Rh substitution in L1{sub 0} FePt modified the local atomic environment and the corresponding electronic properties, while retaining the ordered L1{sub 0} phase. The analysis of extended x-ray Absorption Fine Structure spectra shows that Rh uniformly substitutes for Pt in L1{sub 0} FePt. A model of antiferromagnetic defects caused by controlled Rh substitution of the Pt site, reducing the T{sub C,} is proposed to interpret this phenomenon and its validity is further examined by ab initio density functional calculations.

  5. Strong pressure dependences of the magnetization and Curie temperature for CrTe and MnAs with NiAs-type structure

    CERN Document Server

    Yamada, H; Kondo, K; Goto, T

    2002-01-01

    To study the strong magneto-volume effects observed in CrTe and MnAs with NiAs-type crystal structure, first-principle band calculations are carried out by a self-consistent linear muffin-tin orbital method within the atomic sphere approximation. The equilibrium volume of the unit cell is obtained as a function of the magnetization M, which gives the volume magnetostriction. The dependence on M of the bulk modulus is also estimated. The coefficients a sub 0 and b sub 0 in the Landau expansion, DELTA E(M) = a sub 0 M sup 2 /2 + b sub 0 M sup 4 /4, are estimated by the fixed-spin-moment method. The calculated results for CrTe and MnAs are compared with those for bcc Fe. It is shown that the values of vertical bar a sub 0 vertical bar and b sub 0 for CrTe and MnAs are so small that the correction term from the magneto-volume coupling constants becomes significant. This fact gives a strong pressure dependence of the spontaneous magnetization. The pressure dependence of the Curie temperature is also discussed by m...

  6. Mechanism for the high Neel temperature in SrTcO_3

    OpenAIRE

    Middey, S.; Nandy, Ashis Kumar; Mahadevan, Priya; Sarma, D. D.

    2011-01-01

    The microscopic origin of the high Neel temperature (T_N) observed experimentally in SrTcO_3 has been examined using a combination of ab-initio electronic structure calculations and mean-field solutions of a multiband Hubbard model. The G-type antiferromagnetic state is found to be robust for a large region of parameter space, with large stabilization energies found, surprisingly, for small values of intraatomic exchange interaction strength as well as large bandwidths. The microscopic origin...

  7. Effect of Mn-site vacancies on the magnetic entropy change and the Curie temperature of La0.67Ca0.33Mn1-xO3 perovskite

    DEFF Research Database (Denmark)

    Chen, Wei; Nie, L.Y.; Xu, Zhao

    2006-01-01

    results show that vacancy doping at the Mn-sites has a significant influence on the magnetic properties of La0.67Ca0.33Mn1-xO3. The Curie temperature decreases monotonically with increasing the Mn-site vacancy concentration x. A remarkable enhancement of the magnetic entropy change has been obtained...... in the La0.67Ca0.33W0.98O3 sample. The entropy change reaches vertical bar Delta S-M vertical bar = 3.10 J kg(-1) K-1 at its Curie temperature (264 K) under an applied magnetic field H = 10 kOe, which is almost the same value as that of pure Gd....

  8. Imaging of local temperature distributions in mesas of high-Tc superconducting terahertz sources

    Science.gov (United States)

    Tsujimoto, M.; Kambara, H.; Maeda, Y.; Yoshioka, Y.; Nakagawa, Y.; Kakeya, I.

    2014-12-01

    Stacks of intrinsic Josephson junctions in high-Tc superconductors are a promising source of intense, continuous, and monochromatic terahertz waves. In this paer, we establish a fluorescence-based temperature imaging system to directly image the surface temperature on a Bi2Sr2CaCu2O8+δ mesa sample. Intense terahertz emissions are observed in both high- and low-bias regimes, where the mesa voltage satisfies the cavity resonance condition. In the high- bias regime, the temperature distributions are shown to be inhomogeneous with a considerable temperature rise. In contrast, in the low-bias regime, the distributions are rather uniform and the local temperature is close to the bath temperature over the entire sample.

  9. Operation of high- Tc SFQ devices at near liquid nitrogen temperature

    Science.gov (United States)

    Kim, Y. H.; Kang, J. H.; Lee, J. M.; Hahn, T. S.; Choi, S. S.; Park, S. J.

    1997-02-01

    As the operating temperature of the SFQ logic circuits gets higher by using high- Tc superconductors, the effect of noise on switching a Josephson junction to the voltage state becomes more important. In this paper, we report our work on high- Tc SFQ RS flip-flop which was made with YBCO thin film deposited on a SrTiO 3 bi-crystal. The circuit operated correctly at 71 K over the 200 computer-generated clock cycles without making errors, where a reset or a set operation was made over one clock cycle. Good agreement between the measured data and the calculation based on the thermal activation theory was obtained. The effective noise temperature used to fit the data was much higher than the physical temperature. This could be due to the instrument noise. Improvement in the measurement set-up might reduce the effective noise temperature. Also our measurement results indicate that the elevation of the operating temperature near the liquid nitrogen temperature may not affect the margin of the circuit.

  10. Characterization of mechano-thermally synthesized Curie temperature-adjusted La{sub 0.8}Sr{sub 0.2}MnO{sub 3} nanoparticles coated with (3-aminopropyl) triethoxysilane

    Energy Technology Data Exchange (ETDEWEB)

    Salili, S.M. [Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH 44242 (United States); School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ataie, A., E-mail: aataie@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Barati, M.R. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Department of Materials Engineering, Monash University, Clayton, Victoria 3800 (Australia); Sadighi, Z. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-08-15

    This research aimed to synthesize nanostructured strontium-doped lanthanum manganite, La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSMO), with its Curie temperature (T{sub c}) adjusted to the therapeutic range, through a mechanothermal route. In order to investigate the effect of heat treatment temperature and duration on the resulting crystallite size, morphology, magnetic behavior and Curie temperature, the starting powder mixture was milled in a planetary ball mill before being subsequently heat treated at distinct temperatures for different time lengths. The composition, morphology, and magnetic behavior were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and vibrating sample magnetometer (VSM). In addition, magnetic properties were further investigated using an alternating current (AC) susceptometer and thermo-magnetic analyzer. 20 h of milling produced a crystallite size reduction leading to a decrease in the heat treatment temperature of LSMO synthesis to 800 °C. Moreover, SEM analysis has shown the morphology of a strong agglomeration of fine nanoparticles. HRTEM showed clear lattice fringes of high crystallinity. The mean crystallite and particle size of 20-hour milled sample heat treated at 1100 °C for 10 h are relatively 69 and 100 nm, respectively. The VSM data at room temperature, indicated a paramagnetic behavior for samples heat treated at 800 °C. However, by increasing heat treatment temperature to 1100 °C, LSMO indicates a ferromagnetic behavior with well-adjusted Curie temperature of 320 K, suitable for hyperthermia applications. Also, reentrant spin glass (RSG) behavior has been found in heat treated samples. The particles are coated with (3-aminopropyl) triethoxysilane (APTES) for biocompatibility purposes; Fourier transform infrared spectroscopy (FTIR) and thermo

  11. Finding new superconductors: the spin-fluctuation gateway to high Tc and possible room temperature superconductivity.

    Science.gov (United States)

    Pines, David

    2013-10-24

    We propose an experiment-based strategy for finding new high transition temperature superconductors that is based on the well-established spin fluctuation magnetic gateway to superconductivity in which the attractive quasiparticle interaction needed for superconductivity comes from their coupling to dynamical spin fluctuations originating in the proximity of the material to an antiferromagnetic state. We show how lessons learned by combining the results of almost three decades of intensive experimental and theoretical study of the cuprates with those found in the decade-long study of a strikingly similar family of unconventional heavy electron superconductors, the 115 materials, can prove helpful in carrying out that search. We conclude that, since Tc in these materials scales approximately with the strength of the interaction, J, between the nearest neighbor local moments in their parent antiferromagnetic state, there may not be a magnetic ceiling that would prevent one from discovering a room temperature superconductor.

  12. Mechanism for Curie temperature variation in La{sub x}Sr{sub 2-x}FeMoO{sub 6} and Ca{sub x}Sr{sub 2-x}FeMoO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Frontera, C.; Rubi, D.; Navarro, J.; Garcia-Munoz, J.L.; Ritter, C.; Fontcuberta, J

    2004-07-15

    By means of high-resolution neutron powder diffraction at 10 K, we have characterized the structural details of La{sub x}Sr{sub 2-x}FeMoO{sub 6} (0{<=}x{<=}0.5) and Ca{sub x}Sr{sub 2-x}FeMoO{sub 6} (0{<=}x{<=}0.6) series of compounds. The Curie temperature (T{sub C}) raises in the La series and slightly decreases in the Ca one. The enhancement of T{sub C} in the La series is attributed to the effect of the conduction band-filling when doping with La.

  13. Depth to Curie temperature or bottom of the magnetic sources in the volcanic zone of la Réunion hot spot

    Science.gov (United States)

    Gailler, Lydie-Sarah; Lénat, Jean-François; Blakely, Richard J.

    2016-09-01

    We present an innovative study to generalize Curie Point Depth (CPD) determinations at the scale of oceanic volcanic islands, an approach which has previously focused largely on continental areas. In order to determine the validity of this technique in oceanic environments, we first tested the approach on sets of sea-floor-spreading anomalies. Assuming that magnetic anomalies are concentrated within the oceanic crust and uppermost mantle, the Curie depth should deepen as oceanic lithosphere increases in age and thickness away from spreading centers. The calculated depths to the magnetic bottom are in agreement with this general pattern. On the basis of this test, we then applied the method to La Réunion Island and surrounding oceanic lithosphere. The calculated extent of magnetic sources lies at depths between 10 and 30 km and exhibits a complex topography, presumably caused by a combination of various magmatic and tectonic lithospheric structures. These calculations indicate that magnetic sources extend well below the crust-mantle interface at this location. To the first order, the bottom of the magnetic surface shallows beneath Réunion and Mauritius Islands due to the thermal effect of the hot spot, and deepens away from La Réunion edifice. On the scale of the Mascarene Basin, several discontinuities in the CPD correlate well with major fracture zones.

  14. Pierre curie, 1859-1906.

    Science.gov (United States)

    Mould, R F

    2007-04-01

    The year 2006 marked 100 years since the death of Pierre Curie. It is therefore appropriate that we remember his life and his work, which was cut short by his untimely death from an accident on the Pont Neuf, Paris, on April 19, 1906. He had already accomplished much during his life, both before the discovery of radium with Marie Curie, in work co-authored with his brother Jacques on piezoelectricity, and afterwards, when he published the results of several experimental studies with radium and radon. He came from a medical family, and his grandfather Pierre Curie was a famous homeopathic physician. He has, in print, unfairly been relegated to the background-his own scientific contributions having been overtaken by the fame of Marie Curie, probably because she outlived him by 28 years.

  15. The magnetic Curie temperature and exchange coupling between cations in tetragonal spinel oxide Mn{sub 2.5}M{sub 0.5}O{sub 4} (M = Co, Ni, Mn, Cr, and Mg) films

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, K.; Cheng, C. W.; Chern, G. [Physics Department and SPIN Research Center, National Chung Cheng University, Chia-Yi, Taiwan, 621 (China)

    2012-04-01

    Mn{sub 3}O{sub 4} is a Jahn-Taller tetragonal ferrite that has a relatively low Curie temperature (T{sub c}) of {approx}43 K due to weak coupling between the canting spins. In this study, we fabricated a series of 100-nm-thick Mn{sub 2.5}M{sub 0.5}O{sub 4} (M = Co, Ni, Mn, Cr, and Mg) films via oxygen-plasma-assisted molecular beam epitaxy and measured the structural and magnetic properties of these films. These films show single phase quality, and the c-axis lattice parameter of pure Mn{sub 3}O{sub 4} is 0.944 nm, with a c/a ratio {approx}1.16, consistent with the bulk values. The replacement of Mn by M (M = Co, Ni, Cr, and Mg) changes the lattice parameters, and the c/a ratio varies between 1.16 and 1.06 depending upon the cation distribution of the films. The magnetic Curie temperatures of these films also vary in the range of 25-66 K in that Ni and Co enhance the T{sub c} whereas Mg reduces the T{sub c} (Cr shows no effect on the T{sub c}). These changes to the T{sub c} are related to both the element electronic state and the cation distributions in these compounds. As a non-collinear spin configuration can induce electrical polarization, the present study provides a systematic way to enhance the magnetic transition temperature in tetragonal spinel ferrites.

  16. X-ray MCD Measurements in a high Tc molecular-based magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    1996-01-01

    The molecular based magnet Cs^(I)[Ni^(II)Cr^(III)(CN)6]. 2H2O is a ferromagnet with a Curie temperature Tc = 90 K. Its structure consists of face centred cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray Magnetic Circular Dichroism (XMCD) at nickel L2,3 edges. It

  17. X-ray MCD Measurements in a high Tc molecular-based magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    2001-01-01

    The molecular based magnet Cs^(I)[Ni^(II)Cr^(III)(CN)6]. 2H2O is a ferromagnet with a Curie temperature Tc = 90 K. Its structure consists of face centred cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray Magnetic Circular Dichroism (XMCD) at nickel L2,3 edges. It cl

  18. Measurement of Magnetic Moment at the Atomic Scale in a High TC Molecular Based Magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    2001-01-01

    The molecular-based magnet Cs^(I) [Ni^(II) Cr^(III) (CN)6]-2H2O is a ferromagnetic with a Curie temperature TC ) 90 K. Its structure consists of face-centered cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray magnetic circular dichroism (XMCD) at nickel L2,3 edges.

  19. Piezoelectric properties of low loss and high Curie temperature (Bi, La)FeO_3-Pb(Ti, Mn)O_3 ceramics with Mn doping

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Piezoelectric ceramics of 0.6(Bi0.9La0.1)FeO3-0.4Pb(Ti1-xMnx)O3 (BLF-PTM) for x=0, 0.01, 0.02, and 0.03 were prepared by sol-gel process combined with a solid-state reaction method. The tan? for BLF-PTM of x=0.01 is just 0.006 at 1 kHz, drastically decreasing by using Mn dopants. The TC increases to 490 ℃ for BLF-PTM of x=0.02. Furthermore, Mn modification effectively enhances the poling state and the piezoelectric properties of BLF-PTM. The kp, Qm, d33, and g33 of 0.34, 403, and 124 pC1·N-1 and 37×10-3 Vm·...

  20. Structural and magnetic properties of some pseudo-binary and ternary compounds at high curie temperature prepared in the systems: -) rare earth (Nd, Sm) iron hydrogen, -) gadolinium iron aluminium, and -) uranium iron or cobalt silicon or germanium; Proprietes structurales et magnetiques de quelques composes pseudobinaires et ternaires ferromagnetiques a temperature de curie elevee prepares dans les systemes: -) terres rares Nd Sm fer hydrogene, -) gadolinium fer aluminium, and -) uranium fer ou cobalt silicium ou germanium

    Energy Technology Data Exchange (ETDEWEB)

    Berlureau, T

    1991-07-15

    This work highlights the importance of crystal and chemical studies for understanding the magnetic properties of systems as complex as inter-metallic compounds involving rare-earth elements, uranium, silicon or germanium. With a view of finding new compounds with high Curie temperature and strong magneto-crystal anisotropy, it appears that uranium compounds such as UFe{sub 10}Si{sub 2}, UCo{sub 10}Si{sub 2}, U(Fe{sub 10-x}Co{sub x})Si{sub 2} and U{sub 2}M{sub 17-y}X{sub y} where M is Fe or Co and Y is Si or Ge, are interesting because of the 5f orbital that can form bands through direct overlapping and can link itself very strongly with orbitals of nearby atoms.

  1. On the Fulfillment of Curie's Law in Magnetic Fluids

    Science.gov (United States)

    Zhernovoi, A. I.; Dyachenko, S. V.

    2015-05-01

    A fulfillment of Curie's law in magnetic fluids provides an option of their thermometric applications to measure thermodynamic temperature. On the other hand, it was shown elsewhere that the initial magnetic susceptibility χ of magnetic fluids follows Curie-Weiss's law rather than Curie's law. To obtain its values, use was made of the formula χ = M/N0, where M is magnetization, and N0 is the external magnetic field strength without any specimen. This work deals with investigations of the dependence of magnetic susceptibility of magnetic fluid on temperature for the cases where its values are found via the following formulas: 1) χ = M/N0, and 2) χ = Mμ0/M, where M is the magnetic field induction inside the specimen. It is found that in the first case the temperature dependence of χ obeys Curie-Weiss's law while in the second case - Curie's law. The reason for this results from the fact that induction M acting on the particles of magnetic fluid is noticeably higher than that of the external field, M0.

  2. Irreversible structure change of the as prepared FeMnP{sub 1−x}Si{sub x}-structure on the initial cooling through the curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Höglin, Viktor, E-mail: viktor.hoglin@kemi.uu.se [Department of Chemistry – Ångström Laboratory, Box 538, 751 21 Uppsala (Sweden); Cedervall, Johan [Department of Chemistry – Ångström Laboratory, Box 538, 751 21 Uppsala (Sweden); Andersson, Mikael Svante; Sarkar, Tapati; Nordblad, Per [Department of Engineering Sciences, Solid State Physics, Box 534, 751 21 Uppsala (Sweden); Sahlberg, Martin [Department of Chemistry – Ångström Laboratory, Box 538, 751 21 Uppsala (Sweden)

    2015-01-15

    FeMnP{sub 0.75}Si{sub 0.25} experiences a first order para- to ferromagnetic transition at about 200 K. In common with some other alloy compositions crystallizing in the Fe{sub 2}P structure, the magnetic transition of the as prepared alloy occurs at a lower temperature than on subsequent cooling events. This virgin effect is found to be accompanied by a magnetostrictively induced irreversible structure change that persists on succeeding cooling heating cycles. These findings provide means to understand and control the thermal hysteresis of the (Fe{sub 1−x}Mn{sub x}){sub 2}P{sub 1−y}Si{sub y} alloy system which is a promising material class for use in magnetocaloric refrigerators. - Highlights: • FeMnP{sub 1−x}Si{sub x} exhibits a first order phase transition at the Curie temperature (T{sub c}). • The lattice parameters exhibit a discontinuous change at the transition. • The structure is permanently altered by the initial cooling through T{sub c}. • The transition temperature on cooling is enhanced by initial cooling. • Subsequent cooling/heating does not cause further changes of T{sub c}.

  3. Co-doped LaLa1-xSrxTiO3-d : A Diluted Magnetic Oxide System with High Curie Temperature

    OpenAIRE

    2002-01-01

    Ferromagnetism is observed at and above room temperature in pulsed laser deposited epitaxial films of Co-doped Ti-based oxide perovskite (La1-xSrxTiO3-d). The system has the characteristics of an intrinsic diluted magnetic semiconductor (metal) at low concentrations (

  4. Compositional dependence of magnetization reversal mechanism, magnetic interaction and Curie temperature of Co{sub 1−x}Sr{sub x}Fe{sub 2}O{sub 4} spinel thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi, Ali, E-mail: ali13912001@yahoo.com

    2015-10-05

    Highlights: • Nanoparticles and thin films of Co{sub 1−x}Sr{sub x}Fe{sub 2}O{sub 4} were successfully synthesized by a sol–gel process. • The value of strength of interaction was enhanced from −0.23 for x = 0 to −0.75 for x = 0.5. • The magnetization reversal process for x = 0, 0.1 was almost controlled by Kondorsky models. • The reversal mechanism for x = 0.2–0.5 obey the Stoner–Wohlfarth rule. - Abstract: Co{sub 1−x}Sr{sub x}Fe{sub 2}O{sub 4}, (x varies from 0 to 0.5 in a step of 0.1) nanoparticles were formed by means of sol–gel processing method. The morphological and structural features of nanoparticles were evaluated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FE-SEM) equipped by EDS analysis, Mössbauer spectroscopy and vibrating sample magnetometer. It was found that almost narrow size distribution of nanoparticles with cation distribution occupancy preference in octahedral site was synthesized. The nanoparticles were used for addition in subsequent solution for fabricating ferrite thin films with similar mentioned chemical composition. Several techniques including FE-SEM, atomic force microscopy and vibrating sample magnetometer were employed to find the role of strontium cation distribution on the structural and magnetic properties of films. The Curie temperature, coercivity and magnetic interaction which was evaluated by Henkel plot were reduced by an increase in substitution contents. Coercivity of thin films reduced from 0.65 MA/m to 0.39 MA/m and Curie temperature declined from 690 to 455 °C. The value of strength of interaction was enhanced from −0.23 for x = 0 to −0.75 for x = 0.5. Angular dependence of coercivity proved that the magnetization reversal process was accompanied by the combination of domain wall motion and Stoner–Wohlfarth rotation, however for thin film with x = 0.2–0.5, the reversal mechanism obey the Stoner–Wohlfarth rule.

  5. Cluster method calculation of the Curie temperature and exchange parameters for the magnetocaloric compounds MnFeAs {sub x} P{sub 1-x} (0.25≤ x ≤0.65) and hexagonal MnFeAs

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, Osvaldo F., E-mail: osvaldo.neto@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis (Brazil). Departamento de Fisica

    2013-08-15

    A wealth of experimental and theoretical data on the crystallographic and magnetic properties of the magnetocaloric compounds MnFeAs {sub x} P{sub 1-x} (0.25 ≤ x ≤0.65) and MnFeAs has become available in the last decade. By analyzing the data and treating the spin interactions with Callen's cluster expansion method, we extrapolate first-principle results for the exchange-coupling constants of MnFeAs to the P-substituted compounds and find Curie temperatures that agree, within 5 % deviation, with experiment. Simulations with different coupling parameters show that T{sub c} is weakly dependent on the Fe-Fe interactions. Analysis of lattice expansion as a function of composition shows that changes in the lattice parameters a and c have opposite effects upon the strength of the magnetic interactions between ions. The results indicate that the cluster expansion method provides reliable estimates of magnetic properties, even for metallic compounds characterized by multiple interactions among ions with distinct magnetic moments. (author)

  6. Magnetism and magnetic entropy change in LaFe11Al2Cx compounds around room temperature

    Institute of Scientific and Technical Information of China (English)

    Wang Fang; Chen Yuan-Fu; Wang Guang-Jun; Sun Ji-Rong; Shen Bao-Gen

    2004-01-01

    Magnetism and magnetic entropy changes in LaFe11Al2Cx (x=0.0, 0.2 and 0.5) compounds have been investigated.The Curie temperature TC is conveniently controlled from 200K to room temperature by varying the carbon concentration. Large magnetic entropy change is obtained over a wide temperature range due to the high magnetization and the drastic decrease in the magnetization around TC. The large magnetic entropy change in wide temperature range,low cost and the convenience of controlling TC suggest that the LaFe11Al2Cx compounds are promising candidates for magnetic refrigerants in the corresponding temperature range.

  7. Ab initio and Monte Carlo investigations of structural, electronic and magnetic properties of new ferromagnetic Heusler alloys with high Curie temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Dannenberg, Antje

    2011-08-30

    The mechanism which causes many of the unusual thermomechanical properties of martensitic alloys, as for example, superelasticity and the shape-memory effect, is the martensitic transformation. The prototype ferromagnetic shape memory alloy (FSMA) is Ni{sub 2}MnGa. But a technological breakthrough is missing due to its poor ductility and low operation temperatures. The goal of this thesis is the proposal of new FSMA appropriate for future technological applications. I focus on X{sub 2}YZ Heusler alloys which are mainly based on Mn, Fe, Co, and Ni for the X and Y sites and Z=Ga or Zn. The big challenge of this work is to find material classes which combine the unique magnetomechanical properties of FSMA which are large recoverable magnetostrictive strains, high magnetocrystalline anisotropy energy, and highly mobile twin boundaries with transformation temperatures clearly above room temperature and a reduced brittleness. Such a study, providing material classes which from a theoretical point of view are promising candidates for future FSMA, will help the experimental physicists to select interesting subgroups in the vast number of possible chemical compositions of X{sub 2}YZ Heusler alloys. I have systematically varied the composition in the new Heusler alloys in order to find trends indicating generic tendencies of the material properties, for instance, as a function of the valence electron concentration e/a. A main feature of this thesis is the attempt to find the origin of the competing structural ordering tendencies between conventional X{sub 2}YZ and inverse (XY)XZ Heusler structures which are observed for all systems investigated. In the first part of this work the accuracy and predictive power of ab initio and Monte Carlo simulations is demonstrated by reproducing the experimental phase diagram of Ni-Mn-(Ga,In,Sn,Sb). The linear increasing and decreasing slopes of T{sub M} and T{sub C} can be reproduced by total and free energy calculations and the analysis

  8. Morphology and Curie temperature engineering in crystalline La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films on Si by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Nori, Rajashree, E-mail: rajsre@ee.iitb.ac.in; Ganguly, U.; Ravi Chandra Raju, N.; Pinto, R.; Ramgopal Rao, V. [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology-Bombay (IIT-B), Mumbai 400076 (India); Kale, S. N. [Department of Applied Physics, Defence Institute of Advanced Technology (DIAT), Pune 411025 (India); Sutar, D. S. [Central Surface Analytical Facility, Indian Institute of Technology-Bombay (IIT-B), Mumbai 400076 (India)

    2014-01-21

    Of all the colossal magnetoresistant manganites, La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) exhibits magnetic and electronic state transitions above room temperature, and therefore holds immense technological potential in spintronic devices and hybrid heterojunctions. As the first step towards this goal, it needs to be integrated with silicon via a well-defined process that provides morphology and phase control, along with reproducibility. This work demonstrates the development of pulsed laser deposition (PLD) process parameter regimes for dense and columnar morphology LSMO films directly on Si. These regimes are postulated on the foundations of a pressure-distance scaling law and their limits are defined post experimental validation. The laser spot size is seen to play an important role in tandem with the pressure-distance scaling law to provide morphology control during LSMO deposition on lattice-mismatched Si substrate. Additionally, phase stability of the deposited films in these regimes is evaluated through magnetometry measurements and the Curie temperatures obtained are 349 K (for dense morphology) and 355 K (for columnar morphology)—the highest reported for LSMO films on Si so far. X-ray diffraction studies on phase evolution with variation in laser energy density and substrate temperature reveals the emergence of texture. Quantitative limits for all the key PLD process parameters are demonstrated in order enable morphological and structural engineering of LSMO films deposited directly on Si. These results are expected to boost the realization of top-down and bottom-up LSMO device architectures on the Si platform for a variety of applications.

  9. Marie Curie during ORT4

    Science.gov (United States)

    2003-01-01

    Marie Curie rover drives down the rear ramp during Operational Readiness Test (ORT) 4.Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over thenext ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  10. Marie Curie during ORT6

    Science.gov (United States)

    2003-01-01

    Marie Curie sits on the lander petal prior to deployment during the pre launch Operations Readiness Test (ORT) 6.Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over thenext ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  11. Curie and Pauli Spins in Lithium Intercalated MCMB

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The ESR signal of lithium intercalated MCMB can be well simulated by combination of a Lorentz curve and a Gauss curve. The ESR intensity of the Lorentz component is essentially independent of temperature while the Gauss component shows a linear change with the reciprocal of temperature, indicative of Pauli spin and Curie spin, respectively. The former is probably associated with the ordered (graphitized) structures while the latter with the disordered structures in the sample.

  12. Radium, Marie Curie and modern science.

    Science.gov (United States)

    Langevin-Joliot, H

    1998-11-01

    In 1898, the discovery of two new elements, polonium and radium, reawakened interest in the topic of uranic rays discovered 2 years before by H. Becquerel. Radioactivity, a name coined by Marie Curie, became a major research field for decades. The contrasting personalities of Pierre Curie, already a first-rank physicist, and of the young Marie Curie-Sklodowska as they undertook their common work are described. It is shown how a well-chosen quantitative method and a systematic approach combining physics and chemistry led to the discovery within less than 1 year. The special role of radium and the determination of its atomic weight by Marie Curie followed by her long-term program for accumulating pure radium salts are emphasized. The first woman with a full professorship at a French University, Marie Curie created and managed the Radium Institute.

  13. Pierre Curie: the anonymous neurosurgical contributor.

    Science.gov (United States)

    Man, Karen; Sabourin, Victor M; Gandhi, Chirag D; Carmel, Peter W; Prestigiacomo, Charles J

    2015-07-01

    Pierre Curie, best known as a Nobel Laureate in Physics for his co-contributions to the field of radioactivity alongside research partner and wife Marie Curie, died suddenly in 1906 from a street accident in Paris. Tragically, his skull was crushed under the wheel of a horse-drawn carriage. This article attempts to honor the life and achievements of Pierre Curie, whose trailblazing work in radioactivity and piezoelectricity set into motion a wide range of technological developments that have culminated in the advent of numerous techniques used in neurological surgery today. These innovations include brachytherapy, Gamma Knife radiosurgery, focused ultrasound, and haptic feedback in robotic surgery.

  14. The behaviour of physical quantities in thin films near the Curie point

    Science.gov (United States)

    Korneta, W.; Pytel, Z.

    1982-05-01

    The Valenta model of a thin ferromagnetic film in the critical region above the Curie point has been considered. Spatial and temperature dependence for spin correlation time and magnetic susceptibility has been obtained and discussed. The results have been generalized and expressions describing the behaviour of any physical quantity in more complicated models of a thin ferromagnetic film near the Curie temperature have been given.

  15. Temperature dependence of critical current of heterostructures YBCO-STO-LCMO nearly Tc

    CERN Document Server

    Khokhlov, V A; Drobotko, V F; Levchenko, G G; Mikheenko, P N; Chakalov, R; Muirhead, C R

    2003-01-01

    The complex differential susceptibility a pure YBCO film and YBCO-STO-LCMO structures of different STO width (0; 2; 7 nm) is studied. It is shown, that a decrease of superconducting transition temperature T sub o nset and critical current density j sub c is observed, as expected for the structure YBCO-LCMO in comparison with the pure YBCO film. Conversely, the YBCO-STO-LCMO structures display an increase in T sub o nset; as for j sub c , it increases in the structure with 2 nm STO and decreases in that with 7 nm STO. It is suggested the pinning mechanism of vortices undergoes a change with decreasing temperature.

  16. Curie surface of Borborema Province, Brazil

    Science.gov (United States)

    Correa, Raphael T.; Vidotti, Roberta M.; Oksum, Erdinc

    2016-06-01

    The Curie surface interpreted from magnetic data through spatial frequency domain techniques is used to provide information on the thermal structure of Borborema Province. The Borborema Province is part of the neoproterozoic collision of an orogenic system situated between the São Francisco-Congo and São Luís-West Africa cratons, which formed the Gondwana Supercontinent. The Curie surface of Borborema Province varies from 18 to 59 km, which reveals the complexity in the crustal composition of the study area. The thermal structure shows different crustal blocks separated by the main shear zones, which corroborates the evolution model of allochthonous terranes. The Curie surface signature for the west portion of Pernambuco Shear Zone may indicate processes of mantle serpentinization, once the Curie isotherm is deeper than Mohorovic discontinuity. In this region, the amplitude of Bouguer anomaly decreases, which corroborates long wavelength anomaly observed in the magnetic anomaly. We interpreted this pattern as evidence of the Brasiliano-Pan-Africano's subduction/collision event. Earthquakes in the region are concentrated mainly in shallow Curie surface regions (less resistant crust) and in transition zones between warm and cold blocks. We calculated the horizontal gradient of the Curie depth to emphasize the signature of contact between the thermal blocks. These regions mark possible crustal discontinuities, and have high correlation with orogenic gold occurrence in the study area.

  17. Development of TC4 ELI Titanium Alloy Rod under Ultra Low Temperature%在超低温下使用的TC4 ELI钛合金锻棒的研制

    Institute of Scientific and Technical Information of China (English)

    陈国财; 单学锋; 陈苏; 晁雷; 杨文甲; 冯新; 闫东辉

    2012-01-01

    Under ultra low temperature, TC4 ELI titanium alloy be competent for the work only under - 196 °C . According to the requirement of a project, development of TC4 ELI titanium alloy rod under ultra low temperature( -253 °C ) was carried out. In order to increase the strength and ductility, several important technological parameters were optimized including oxygen content control, alloy purity improvement and the latest " 331 " upsetting and stretching forging process application. The results show that the high purity is the key parameter to increase the ductility of TC4 ELI titanium alloy at -253 °C. The mechanical properties of φ100 mm rod from "331" upsetting and stretching forging process are: 1480~1510 MPa for Rm , 1 240~1 290 MPa for Rp0.2, 12. 67% ~ 18. 67 % for A and 27. 8%~ 33. 3% for Z. The mechanical properties have satisfied the demand of J901 -01 -2009.%在低温下,TC4 ELI钛合金只能在-196℃下使用.根据某工程的实际需要,开发超低温(- 253 ℃)用TC4 ELI钛合金锻棒.从控制氧含量和提高合金纯洁度入手,并在锻造工艺上采用最新“三三一”镦拔组合变形工艺来提升锻棒的组织均匀性,来提高强度和塑性.实验结果表明:高纯洁度是提高TC4 ELI钛合金在- 253℃下塑性的基础;“三三一”镦拔变形工艺制得φ100 mm棒材的超低温力学性能较好,其Rm为1 480 ~1 510 MPa,Rp0.2为1 240 ~1 290MPa,A为12.67% ~ 18.67%,Z为27.8% ~33.3%,满足工程技术性能指标要求(J901 - 01 - 2009).

  18. Spin dynamics in a Curie-switch.

    Science.gov (United States)

    Kravets, A F; Tovstolytkin, A I; Dzhezherya, Yu I; Polishchuk, D M; Kozak, I M; Korenivski, V

    2015-11-11

    Ferromagnetic resonance properties of F1/f/F2/AF multilayers, where weakly ferromagnetic spacer f is sandwiched between strongly ferromagnetic layers F1 and F2, with F1 being magnetically soft and F2-magnetically hard due to exchange pinning to antiferromagnetic layer AF, are investigated. Spacer-mediated exchange coupling is shown to strongly affect the resonance fields of both F1 and F2 layers. Our theoretical calculations as well as measurements show that the key magnetic parameters of the spacer, which govern the ferromagnetic resonance in F1/f/F2/AF, are the magnetic exchange length (Λ), effective saturation magnetization at T  =  0 (m0) and effective Curie temperature (T(C)(eff)). The values of these key parameters are deduced from the experimental data for multilayers with f  =  Ni(x)Cu(100-x), for the key ranges in the Ni-concentration (x = 54 ÷ 70 at. %) and spacer thickness (d = 3 ÷ 6 nm). The results obtained provide a deeper insight into thermally-controlled spin precession and switching in magnetic nanostructures, with potential applications in spin-based oscillators and memory devices.

  19. Microscopic Superconductivity and Room Temperature Electronics of High-Tc Cuprates

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-Sui; CHEN Wan-Fang

    2008-01-01

    This paper points out that the Landau criterion for macroscopic superfluidity of He H is only a criterion for microscopic superfluidity of 4He, extends the Landau criterion to microscopic superconductivity in fermions (electron and hole) system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-To cuprates.

  20. Non-Universal temperature dependencies of the low frequency ac magnetic susceptibility in high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Di Gioacchino, D.; Celani, F.; Tripodi, P. [Istituto Nazionale di Fisica Nucleare, Frascati, RM (Italy). Laboratori Nazionali di Frascati; Testa, A.M. [Consiglio Nazionale per le Ricerche, Monterotondo, RM, (Italy). Istituto di Chimica dei Materiali; Pace, S. [INFM, Univ. Salerno, Salerno (Italy). Dept. of Physics

    1999-07-01

    The paper is organized as follows. In Sec. 2 the non-linear diffusion problem is formulated in terms of a partial differential equation, together with the parallel resistor model for the 1-5 characteristics. To study in some detail the effects of thermally activated processes in different cases, we have chosen different temperature functional dependencies for the pinning potential, U{sub p}(T), and the critical current density, J{sub c}(T), related to particular pinning models. Local magnetic field profiles, magnetization cycles and {chi}n (T) are discussed in Sec. 3. Moreover, a comparison of numerical results with available experimental data and analytical approximated predictions is also presented. Finally, Sec. 4 is devoted to summary and conclusions.

  1. Growth and pyroelectric properties of high Curie temperature relaxor-based ferroelectric Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary single crystal

    Science.gov (United States)

    Yu, Ping; Wang, Feifei; Zhou, Dan; Ge, Wenwei; Zhao, Xiangyong; Luo, Haosu; Sun, Jinglan; Meng, Xiangjian; Chu, Junhao

    2008-06-01

    To enhance the service temperature of relaxor-PbTiO3 pyroelectric single crystals, high quality ternary perovskite single crystal was grown by a modified Bridgman technique. Analyzed by x-ray fluorescence, the as-grown crystal is 0.41Pb(In1/2Nb1/2)O3-0.17Pb(Mg1/3Nb2/3)O3-0.42PbTiO3 [PIMNT(41/17/42)], which appears to be a tetragonal ferroelectric phase with relatively high Curie temperature of 253°C. It exhibits the relative permittivity of 487 and low dielectric loss of 0.3% at 50Hz and room temperature. The pyroelectric properties with a pyroelectric coefficient of 5.7×10-4C /m2K and a detectivity of 6.34×10-5Pa-1/2 would satisfy the needs of operation as a high Curie temperature material. The results show that PIMNT crystal with better temperature stability, compared with the pure PMNT single crystals, is a good candidate as an infrared detector material.

  2. Pioneers of nuclear medicine, Madame Curie.

    Science.gov (United States)

    Grammaticos, Philip C

    2004-01-01

    Among those who have made important discoveries in the field of radioactivity and thus helped in the development of nuclear medicine as an identical entity are: Heinrich Hertz who in 1886 demonstrated the existence of radiowaves. In 1895 Wilhelm Röntgen discovered the X-rays. In 1896 H. Becquerel described the phenomenon of radioactivity. He showed that a radioactive uranium salt was emitting radioactivity which passing through a metal foil darkened a photographic plate. An analogous experiment performed by S.Thomson in London was announced to the president of the Royal Society of London before the time H.Becquerel announced his discovery but Thomson never claimed priority for his discovery. Muarie Sklodowska Curie (1867-1934) was undoubtedly the most important person to attribute to the discovery of radioactivity. In 1898 she discovered radium as a natural radioactive element. This is how she describes the hard time she had, working with her husband Pierre Curie (1859-1906) for the discovery of radium and polonium: "During the first year we did not go to the theater or to a concert or visited friends. I miss my relatives, my father and my daughter that I see every morning and only for a little while. But I do not complain...". In presenting her discovery of radium, Madame Curie said: " ...in the hands of a criminal, radium is very dangerous. So we must often ask ourselves: will humanity earn or lose from this discovery? I, myself belong to those who believe the former...". The notebooks that Madame Curie had when she was working with radium and other radioactive elements like polonium, thorium and uranium are now kept in Paris. They are contaminated with radioactive materials having very long half-lives and for this reason anyone who wishes to have access to these notes should sign that he takes full responsibility. There are some more interesting points in Madame Curie's life which may not be widely known like: Although her full name is Maria Sklodowska-Curie

  3. Enhancing electric-field control of ferromagnetism through nanoscale engineering of high-Tc MnxGe1-x nanomesh

    Science.gov (United States)

    Nie, Tianxiao; Tang, Jianshi; Kou, Xufeng; Gen, Yin; Lee, Shengwei; Zhu, Xiaodan; He, Qinglin; Chang, Li-Te; Murata, Koichi; Fan, Yabin; Wang, Kang L.

    2016-10-01

    Voltage control of magnetism in ferromagnetic semiconductor has emerged as an appealing solution to significantly reduce the power dissipation and variability beyond current CMOS technology. However, it has been proven to be very challenging to achieve a candidate with high Curie temperature (Tc), controllable ferromagnetism and easy integration with current Si technology. Here we report the effective electric-field control of both ferromagnetism and magnetoresistance in unique MnxGe1-x nanomeshes fabricated by nanosphere lithography, in which a Tc above 400 K is demonstrated as a result of size/quantum confinement. Furthermore, by adjusting Mn doping concentration, extremely giant magnetoresistance is realized from ~8,000% at 30 K to 75% at 300 K at 4 T, which arises from a geometrically enhanced magnetoresistance effect of the unique mesh structure. Our results may provide a paradigm for fundamentally understanding the high Tc in ferromagnetic semiconductor nanostructure and realizing electric-field control of magnetoresistance for future spintronic applications.

  4. Enhanced 99 Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Luksic, Steven A.; Wang, Guohui; Saslow, Sarah; Kim, Dong-Sang; Schweiger, Michael J.; Soderquist, Chuck Z.; Bowden, Mark E.; Lukens, Wayne W.; Kruger, Albert A.

    2017-11-01

    Technetium (99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals. Two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 – 1,000 oC. After being cooled, the solid glass specimens prepared at different temperatures were analyzed for Tc oxidation state using Tc K-edge XANES. In most samples, Tc was partially oxidized from Tc(IV) to Tc(VII) as the melt temperature increased. However, Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were moderately higher than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.

  5. Women who Worked with Marie Curie.

    Science.gov (United States)

    Pigeard-Micault, Natalie

    2015-06-01

    Marie Curie directed a research laboratory for 28 years. Between 1906 and 1934, forty five women worked under her guidance. Some were, and are, well-known in their own countries as their first woman full professor such as Ellen Gleditsch or Margaret von Wrangel, but for twenty eight of them, who were often French, nothing has ever been written. The strong presence of women in Marie Curie's laboratory has often been highlighted and has been considered as an exception, and the result of deliberate choice. Of course, these women did not choose this workplace by accident. They knew its director was a woman, a laureate of one, and after 1911, two Nobel Prizes, who was leading a well-equipped laboratory with an important radioactive source. But how did Marie Curie selected her collaborators among the many applications she received? Was her choice influenced by gender? A prosopographical research based on genealogical researches and new sources explains this presence contextually and sheds light on several questions : where did these women come from, what were their social and geographic origins, did they occupy any specific cultural or technical area inside Curie's lab, what future did they have after the laboratory? Through their lives, we can question the existence, or not, of a one profile of the female researcher in scientific areas in France.

  6. Marie Curie: In the Laboratory and on the Battlefield

    Science.gov (United States)

    Badash, Lawrence

    2003-07-01

    This year is the centennial of the Nobel Prize in Physics shared by Henri Becquerel and the Curies for their pioneering work on radioactivity. But Marie Curie's contribution to the medical use of x rays is not widely known.

  7. The activity of TcCYS4 modified by variations in pH and temperature can affect symptoms of witches' broom disease of cocoa, caused by the fungus Moniliophthora perniciosa.

    Directory of Open Access Journals (Sweden)

    Ana Camila Oliveira Freitas

    Full Text Available The phytocystatins regulate various physiological processes in plants, including responses to biotic and abiotic stresses, mainly because they act as inhibitors of cysteine proteases. In this study, we have analyzed four cystatins from Theobroma cacao L. previously identified in ESTs libraries of the interaction with the fungus Moniliophthora perniciosa and named TcCYS1, TcCYS2, TcCYS3 and TcCYS4. The recombinant cystatins were purified and subjected to the heat treatment, at different temperatures, and their thermostabilities were monitored using their ability to inhibit papain protease. TcCYS1 was sensitive to temperatures above 50°C, while TcCYS2, TcCYS3, and TcCYS4 were thermostable. TcCYS4 presented a decrease of inhibitory activity when it was treated at temperatures between 60 and 70°C, with the greater decrease occurring at 65°C. Analyses by native gel electrophoresis and size-exclusion chromatography showed that TcCYS4 forms oligomers at temperatures between 60 and 70°C, condition where reduction of inhibitory activity was observed. TcCYS4 oligomers remain stable for up to 20 days after heat treatment and are undone after treatment at 80°C. TcCYS4 presented approximately 90% of inhibitory activity at pH values between 5 and 9. This protein treated at temperatures above 45°C and pH 5 presented reduced inhibitory activity against papain, suggesting that the pH 5 enhances the formation of TcCYS4 oligomers. A variation in the titratable acidity was observed in tissues of T. cacao during the symptoms of witches' broom disease. Our findings suggest that the oligomerization of TcCYS4, favored by variations in pH, is an endergonic process. We speculate that this process can be involved in the development of the symptoms of witches' broom disease in cocoa.

  8. Curie Transition of NC Nickel by Mechanical Spectroscopy and Magnetization Study

    Institute of Scientific and Technical Information of China (English)

    LI Ping-Yun; CAO Zhen-Hua; ZHANG Xi-Yan; WU Xiao-Lei; HUANG Yi-Neng; MENG Xiang-Kang

    2009-01-01

    Mechanical spectroscopy measurement is performed to study the internal friction of nanocrystalline (NC) nickel with an average grain size of 23 nm from room temperature to 610 K.An internal friction peak is observed at about 550 K,which corresponds to the Curie transition process of the NC nickel according to the result of magnetization test.Moreover,the fact that the Curie temperature of NC nickel is lower than that of coarse-grained nickel is explained by an analytical model based on the weakening of cohesive energy.

  9. Curie law for systems described by kappa distributions

    Science.gov (United States)

    Livadiotis, George

    2016-01-01

    We derive the magnetization of a system, Pierre Curie's law, for paramagnetic particles out of thermal equilibrium described by kappa distributions. The analysis uses the theory and formulation of the kappa distributions that describe particle systems with a non-zero potential energy. Among other results, emphasis is placed on the effect of kappa distribution on the phenomenon of having strong magnetization at high temperatures. At thermal equilibrium, high temperature leads to weak magnetization. Out of thermal equilibrium, however, strong magnetization at high temperatures is rather possible, if the paramagnetic particle systems reside far from thermal equilibrium, i.e., at small values of kappa. The application of the theory to the space plasma at the outer boundaries of our heliosphere, the inner heliosheath, leads to an estimation of the ion magnetic moment for this space plasma, that is, μ ≈ 138+/-7 \\text{eV/nT} .

  10. Relationship between Curie isotherm surface and Moho discontinuity in the Arabian shield, Saudi Arabia

    Science.gov (United States)

    Aboud, Essam; Alotaibi, Abdulrahman M.; Saud, Ramzi

    2016-10-01

    The Arabian shield is a Precambrian complex of igneous and metamorphic rocks located approximately one-third of the way across the western Arabian Peninsula, with uncommon exposures along the Red Sea coast. We used aeromagnetic data acquired by others over the past several decades to estimate the depth to the Curie temperature isotherm throughout this region. Our goal was to further understand the lithospheric structure, thermal activity, and seismicity to assist in geothermal exploration. We also compared the Curie temperature isotherm with the crustal thickness to investigate the possibility that mantle rocks are magnetic in some parts of the Arabian shield. Depths to the Curie isotherm were estimated by dividing the regional aeromagnetic grid into 26 overlapping windows. Each window was then used to estimate the shape of the power spectrum. The windows had dimensions of 250 × 250 km to allow investigation of depths as deep as 50 km. The results show the presence of a Curie isotherm at a depth of 10-20 km near the Red Sea, increasing to 35-45 km in the interior of the Arabian shield. The Curie isotherm generally lies above the Moho in this region but deepens into the mantle in some locations, notably beneath the Asir Terrane.

  11. Effect of temperature-dependent shape anisotropy on coercivity with aligned Stoner-Wohlfarth soft ferromagnets

    OpenAIRE

    He, Lin; Chen, Chinping

    2007-01-01

    The temperature variation effect of shape anisotropy on the coercivity, HC(T), for the aligned Stoner-Wohlfarth (SW) soft ferromagnets, such as fcc Ni, fcc Co and bcc Fe, are investigated within the framework of Neel-Brown (N-B) analysis. An extended N-B equation is thus proposed,by introducing a single dimensionless correction function, the reduced magnetization, m(\\tao) = MS(T)/MS(0), in which \\tao = T/TC is the reduced temperature, MS(T) is the saturation magnetization, and TC is the Curie...

  12. Marie and Pierre Curie. Life in extremes; Marie and Pierre Curie. Leben in Extremen

    Energy Technology Data Exchange (ETDEWEB)

    Roethlein, Brigitte

    2008-07-01

    In Paris in 1894, two young physicists fall in love: Marie Sklodowska and Pierre Curie. They get married and make great contributions to science, research radioactivity and discover new chemical elements. The marriage of Marie and Pierre Curie is quite modern: They work together as equals, share their thoughts and pursue their plans together as partners. They share an absolute interest in science, a love of nature, and a sceptic attitude towards the sophisticated society of the Belle Epoque. They are together 24 hours a day with hardly ever any disagreement. Whenever one of them is ill - which is quite often because of the high level of radioactivity in their laboratory -, the other will nurse him or her. After only twelve years of mutual love, Pierre Curie dies. Marie raises their two daughters on her own and continues her research. In 1911, she will be the first scientist that ever gets a second Nobel Prize. (orig.) [German] Im Paris des Jahres 1894 verlieben sich zwei junge Physiker: Marie Sklodowska und Pierre Curie. Sie heiraten und leisten gemeinsam Grosses fuer die Wissenschaft, erforschen die Radioaktivitaet und entdecken neue chemische Elemente. Zusammen erhalten sie den Nobelpreis. Marie und Pierre Curie fuehren eine Ehe, die ihrer Zeit weit voraus ist: Sie arbeiten gleichberechtigt miteinander, teilen ihre Gedanken und verfolgen ihre Plaene gemeinsam. Beiden eigen ist die absolute wissenschaftliche Neugier, die Liebe zur Natur und die Skepsis gegenueber der mondaenen Gesellschaft der Belle Epoque. Fast jeden Tag sind sie rund um die Uhr zusammen, dabei gibt es selten Spannungen. Wenn einer von beiden gesundheitliche Probleme hat - und das haben sie wegen der radioaktiven Belastung im Labor oft - ist der andere fuer ihn da und pflegt ihn. Nach nur zwoelf gemeinsamen Jahren der Liebe und Arbeit stirbt Pierre Curie. Marie zieht ihre beiden Toechter alleine gross und fuehrt die Forschungen weiter. 1911 erhaelt sie als erster Mensch zum zweiten Mal den

  13. Competing structural ordering tendencies in new high-TC ferromagnetic Fe-Co-based Heusler alloys from ab initio investigations

    Energy Technology Data Exchange (ETDEWEB)

    Dannenberg, Antje; Gruner, Markus; Entel, Peter [Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg (Germany); Wuttig, Manfred [Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742 (United States)

    2011-07-01

    Fe-Co-based Heuslers are candidates for new ferromagnetic shape memory alloys (FSMA) as they promise higher operation temperatures compared with prototype Ni2MnGa. Of interest are also the corresponding binary systems FeZn and Fe3Ga which show a huge magnetostriction. We present results of ab initio and Monte Carlo calculations regarding structural, magnetic, and electronic properties of Fe2CoGa1-xZnx alloys in conventional X2YZ and inverse (XY)XZ Heusler structures. All systems exhibit high Curie temperatures TC. The preference of the cubic inverse structures is believed to originate from the bcc-like environment of two inequivalent Fe atoms and their strong hybridization with the Co- states. Weakening the Co-Fe hybridization by substitution of Ga by Zn reduces this preference and leads to higher TC but simultaneously reduces the miscibility. Despite the strong spin-dependent Fe-Co hybridization we find a localized character of the spin moments. Extraordinary Z-elements like Cu, Ag, and Au or further enhancement of the Zn content induces a martensitic instability also in the inverse structures. Thus, we conclude that it is possible to find new FSMA with rather high Curie temperatures.

  14. Effect of A-site cation substitution on magnetic transition temperature of (LaCa) MnO3

    Institute of Scientific and Technical Information of China (English)

    李可斌; 王守国; 程荣胜; 李西军; 侯登录; 聂向富; 张裕恒

    1999-01-01

    The ferromagnetic transition temperatures have been measured on two bathes of perovskite manganese oxides such as (La1-xRx)2/3Ca1/3MnO3(R=Ce, Pr, Nd, etc.) and La2/3(Ca1-yCd)y)1/3MnO3. It is found that the (La1-xRx)2/3Ca1/3MnO3 samples have obviously different Curie temperature TC although their (the average A-site cation radius) are almost identical, and the TC in the system of (La1-xRx)2/3Ca1/3MnO3 compounds increases with increasing y although decreases slightly. It is suggested that the Curie temperature should be influenced by the average local A-site magnetic moment in the ferromagnetic perovskite manganite system.

  15. Marie Curie's contribution to Medical Physics.

    Science.gov (United States)

    Jean-Claude, Rosenwald; Nüsslin, Fridtjof

    2013-09-01

    On occasion of its 50th anniversary, the International Organization for Medical Physics (IOMP) from now on is going to celebrate annually an International Day of Medical Physics for which the 7th November, the birthday of Marie Sklodowska Curie, a most exceptional character in science at all and a pioneer of medical physics, has been chosen. This article briefly outlines her outstanding personality, sketches her fundamental discovery of radioactivity and emphasizes the impact of her various achievements on the development of medical physics at large.

  16. Near-Curie magnetic anomaly at the Ni/C interface observed by Electron Holography

    DEFF Research Database (Denmark)

    Ferrari, Loris; Matteucci, Giorgio; Schofield, Marvin A

    2010-01-01

    We analyze with electron holography carried out in a transmission electron microscope the near-Curie behavior of magnetism at the edge of a Nickel thin film coated with Carbon. In-situ experiments with finely controlled variations of the sample temperature reveal an anomaly in the ferromagnetic t...

  17. On the dielectric curie-weiss law and diffuse phase transition in ferroelectrics

    NARCIS (Netherlands)

    Jonker, G.H.

    1983-01-01

    A simple derivation of parabolic 1/εr-T curves is obtained by reconsidering the origin of the dielectric Curie-Weiss law. The only assumption needed is the introduction of a non-linear temperature dependance of the macroscopic dielectric polarization in the macroscopic Clausius-Mossotti equation

  18. Increase in the Magnetic Ordering Temperature (Tc) as a Function of the Applied Pressure for A2Mn[Mn(CN)6] (A = K, Rb, Cs) Prussian Blue Analogues.

    Science.gov (United States)

    Sugimoto, M; Yamashita, S; Akutsu, H; Nakazawa, Y; DaSilva, J G; Kareis, C M; Miller, Joel S

    2017-09-05

    Magnetization measurements under pressure reveal that the external hydrostatic pressure significantly increases in the ferrimagnetic transition temperature, Tc, for A2Mn[Mn(CN)6] (A = K, Rb, Cs). In the case of monoclinic A = K and Rb, dTc/dp values are 21.2 and 14.6 K GPa(-1), respectively, and Tc increases by 53 and 39%, respectively, from ambient pressure to 1.0 GPa. The cubic A = Cs compound also shows a monotonous increase with an initial rate of 4.22 K GPa(-1) and about 11.4 K GPa(-1) above 0.6 GPa, and an overall Tc increase by 26% at 1.0 GPa. The increase in Tc is attributed to deformation of the structure such that the Mn(II)-N≡C angle decreases with increasing pressure. The smaller the alkali cation, the greater the decrease in the Mn(II)-N≡C angle induced by pressure and the larger the increase of dTc/dp. This is in accordance with the ambient-pressure structures for A2Mn[Mn(CN)6] (A = K, Rb, Cs), which have decreasing Mn(II)-N≡C angles that correlate to the observed increasing Tcs as K > Rb > Cs. The large increase in Tc for the A = K compound is the highest class among several cyano-bridged metal complexes. The tuning of the transition temperature by such a weak pressure may lead to additional applications such as switching devices.

  19. Effects of Dopant on Depoling Temperature in Modified BiScO3 - PbTiO3

    Science.gov (United States)

    Kowalski, Benjamin; Sehirlioglu, Alp

    2014-01-01

    In recent years there has been a renewed interest for high temperature piezoelectrics for both terrestrial and aerospace applications. These applications are limited in part by the operating temperature, which is usually taken as one half of the Curie temperature (Tc), and is 200C for one of the most widely used commercial piezoelectrics, Pb(Zr,Ti)O3 (PZT). In an effort to increase Tc, subsequent research into high temperature Bi(BB)O3 PbTiO3 piezoelectrics led to the discovery of the morphotropic phase boundary (MPB) in the high-Tc BiScO3 PbTiO3 (BS-PT) system with a Tc of 460C and a d33 of 460 pmV. The Tc marks the ferroelectric to paraelectric phase transformation and while, in general, a phase transformation leads to thermal depoling in piezoelectrics with low or moderate Tcs, for high Tc piezoelectrics thermally assisted dipole rotation can lead to randomization of domains at temperatures below Tc. It becomes necessary to determine the depoling temperature (Td) which dictates the actual working temperature range. By doping for Sc and Ti the Td can be shifted while maintaining similar electromechanical properties as a function of temperature. The effect of this B-site doping on depoling temperature has been explored through the characterization of microstructure and weakhigh field measurements.

  20. Ultrasonic and elastic moduli evidence for Curie temperature (T{sub c}) in Sm{sub 1-x}Sr{sub x}MnO{sub 3} perovskite magnetic materials at x = 0.25, 0.30, 0.37, 0.40 and 0.44

    Energy Technology Data Exchange (ETDEWEB)

    Sankarrajan, S. [Department of Physics, National Engineering College, Kovilpatti 628503, Tamilnadu (India); Aravindan, S.; Rajkumar, M. [Centre for Nano Science and Technology, K.S. Rangasamy College of Technology, K S R Kalvi Nagar, Tiruchengode 637215, Tamilnadu (India); Rajendran, V., E-mail: veerajendran@gmail.co [Centre for Nano Science and Technology, K.S. Rangasamy College of Technology, K S R Kalvi Nagar, Tiruchengode 637215, Tamilnadu (India)

    2009-10-19

    Sm{sub 1-x}Sr{sub x}MnO{sub 3} perovskite manganite materials with different compositions (x = 0.25, 0.30, 0.37, 0.40 and 0.44) have been prepared using solid state reaction technique. On-line ultrasonic velocities and attenuation have been measured over a wide range of temperatures from 120 to 298 K employing through transmission method operated at a fundamental frequency of 5 MHz. In all compositions, Curie temperature (T{sub c}) and Jahn-Teller temperature (T{sub JT}) have been discussed in light of observed interesting results on temperature dependence of ultrasonic parameters. Phase transition from ferromagnetic to canted ferromagnetic state has been observed at T{sub c}. The increase in the magnitude of maximum velocities with change in Sr content at T{sub c} indicates the strength of linear magnetostriction effect. The observed results reveal that T{sub c} value decreases with an increase in Sr content. The existence of Jahn-Teller transition due to electron-phonon interaction and large lattice distortion which is due to the double exchange interactions have been demonstrated from the observed ultrasonic parameters as a function of temperature.

  1. Comparison of MMS Pressure, Temperature, and Horizontal Wind Data With CFH/Ozonesonde and AVAPS Dropsonde Profiles Collected During TC4

    Science.gov (United States)

    Dean-Day, J.; Bui, T.; Chang, C.; Vömel, H.; Korn, E.

    2008-12-01

    During the 2007 Tropical Composition, Cloud and Climate Coupling Experiment (TC4), the Meteorological Measurement System (MMS) derived pressure, temperature and 3-D wind data aboard the NASA DC-8 and WB-57 aircraft. Using GPS altitude as a common vertical coordinate, profiles of airborne data during climb and descent were compared with the same parameters computed following balloon-borne ascent of the Cryogenic Frostpoint Hygrometer (CFH) / Ozonesonde from Juan Santamaria Airport, as well as during rapid descent of Airborne Vertical Advanced Profiling System (AVAPS) Dropsondes, released from the DC-8 aircraft at various locations above Costa Rica and the surrounding oceans. Profiles are selected to minimize natural variability due to space and time separation between platforms. In addition, profile pressure data are compared with an assumed hydrostatic descent from pre-selected altitudes. Mean differences in pressure, temperature, and winds will be discussed with respect to instrument accuracy.

  2. Variations in Moho and Curie depths and heat flow in Eastern and Southeastern Asia

    Science.gov (United States)

    Li, Chun-Feng; Wang, Jian

    2016-03-01

    The Eastern and Southeastern Asian regions witness the strongest land-ocean and lithosphere-asthenosphere interactions. The extreme diversity of geological features warrants a unified study for a better understanding of their geodynamic uniqueness and/or ubiquity from a regional perspective. In this paper we have explored a large coverage of potential field data and have detected high resolution Moho and Curie depths in the aforementioned regions. The oldest continental and oceanic domains, i.e. the North China craton and the Pacific and Indian Ocean have been found thermally perturbed by events probably linked to small-scale convection or serpentinization in the mantle and to numerous volcanic seamounts and ridges. The thermal perturbation has also been observed in proximity of the fossil ridge of the western Philippine Sea Basin, which shows anomalously small Curie depths. The western Pacific marginal seas have the lowest Moho temperature, with Curie depths generally larger than Moho depths. The contrary is true in most parts of easternmost Eurasian continent. Magmatic processes feeding the Permian Emeishan large igneous province could have also been genetically linked to deep mantle/crustal processes beneath the Sichuan Basin. The regionally elongated magnetic features and small Curie depths along the Triassic Yangtze-Indochina plate boundary suggest that the igneous province could be caused by tectonic processes along plate margins, rather than by a deep mantle plume. At the same time, we interpret the Caroline Ridge, the boundary between the Pacific and the Caroline Sea, as a structure having a continental origin, rather than as hotspot or arc volcanism. The surface heat flow is primarily modulated by a deep isotherm through thermal conduction. This concordance is emphasized along many subduction trenches, where zones of large Curie depths often correspond with low heat flow. Local or regional surface heat flow variations cannot be faithfully used in inferring

  3. The life and legacy of Marie Curie.

    Science.gov (United States)

    Rockwell, Sara

    2003-01-01

    Marie Curie was a remarkable woman whose discoveries broke new ground in physics and chemistry and also opened the door for advances in engineering, biology, and medicine. She broke new ground for women in science: she was, for example, the first woman to receive a doctor of science degree in France, the first woman to win Nobel Prize, the first woman to lecture at the Sorbonne, the first person to win two Nobel Prizes, and the first Nobel Laureate whose child also won a Nobel Prize. Her life offers insights into the changing role of women in science and academia over the past century. It also offers examples of many ways in which scientists can, and should, work to improve the educational programs and career opportunities available to those who follow in their footsteps.

  4. Isotope shift of the ferromagnetic transition temperature in itinerant ferromagnets

    Science.gov (United States)

    Yanagisawa, Takashi; Hase, Izumi; Odagiri, Kosuke

    2017-02-01

    We present a theory of the isotope effect of the Curie temperature Tc in itinerant ferromagnets. The isotope effect in ferromagnets occurs via the electron-phonon vertex correction and the effective attractive interaction mediated by the electron-phonon interaction. The decrease of the Debye frequency increases the relative strength of the Coulomb interaction, which results in a positive isotope shift of Tc when the mass M of an atom increases. Following this picture, we evaluate the isotope effect of Tc by using the Stoner theory and a spin-fluctuation theory. When Tc is large enough as large as or more than 100 K, the isotope effect on Tc can be measurable. Recently, precise measurements on the oxygen isotope effect on Tc have been performed for itinerant ferromagnet SrRuO3 with Tc ∼ 160 K. A clear isotope effect has been observed with the positive shift of Tc ∼ 1 K by isotope substitution (16O →18O). This experimental result is consistent with our theory.

  5. Growth of EuO single crystals at reduced temperatures

    Science.gov (United States)

    Ramirez, Daniel C.; Besara, Tiglet; Whalen, Jeffrey B.; Siegrist, Theo

    2017-01-01

    Single crystals of (E u1 -xB ax)O have been grown in a molten barium-magnesium metal flux at temperatures up to 1000 °C, producing single crystals of (E u1 -xB ax)O with barium doping levels ranging from x =0.03 to x =0.25 . Magnetic measurements show that the ferromagnetic Curie temperature TC correlates with the Ba doping levels, and a modified Heisenberg model was used to describe the stoichiometry dependence of TC. Extrapolation of the results indicates that a sample with Ba concentration of x =0.72 should have a TC of 0 K, potentially producing a quantum phase transition in this material.

  6. [Maria Skłodowska-Curie and Piotr Curie an epoch-makingin year 1898].

    Science.gov (United States)

    Wielogórski, Zbigniew

    2012-01-01

    For many reasons the year 1898 was unusual for Maria Skłodowska-Curie and her husband. After defining the subject of the doctoral thesis and choosing Henri Becqerel as thesis supervisor, Maria started intensive experimental work. In the allotted room called storeroom, in conditions that were far too inadequate, they managed to put up a unique measuring equipment composed of instruments whose originator was Pierre Curie. In the ionization chamber and in the piezoelectric quartz charges formed, whose mutual neutralization was shown by the quadrant electrometer. Ionization current, which was measured quantitatively, was proportional to the radiation of the sample. Studying many elements, their compounds and minerals enabled Maria to state that uranium is not the only element endowed with the power of radiation; the second one turned out to be thorium. Anomaly detected in the radiation of uranium minerals made it possible for Maria to draw an extremely important conclusion: radioactive uranium and thorium are not the only elements endowed with such an attribute. Pitchblende, which was studied by the Curie couple, had to contain also other radioactive substances. Gustave Bémont also participated in the chemical analysis of the uranium ore and it is worth reminding that he was involved in the discovery of polonium and uranium. The phenomenon of radioactivity couldn't have been explained if it was not for the sources of strong radioactivity. Those sources undoubtedly could have been the discovered elements but their scanty content in the uranium ore made their isolation very difficult and laborious. Access to industrial remains after procession of pitchblende from Jachymov (Sankt Joachimstahl), obtained owing to the mediation of Eduard Suess, provided the source of this raw material. From it, in a shack also called le hangar, the Curie couple isolated the first samples of the radium salt. This element, later extracted by discoverers on a grand scale and handed over in a

  7. Marie and Pierre Curie and radium: history, mystery, and discovery.

    Science.gov (United States)

    Mould, R F

    1999-09-01

    Commencing with Marie Curie's early life in Poland and the discovery of radium in the rue l'Homond "shed" in Paris in 1898, this paper includes some little known facts. It ends with some unusual uses of and claims for radium, and finally, because Medical Physics is an American journal, details are included of Marie Curie's two visits to the USA.

  8. Defect mediated magnetic interaction and high Tc ferromagnetism in Co doped ZnO nanoparticles.

    Science.gov (United States)

    Pal, Bappaditya; Giri, P K

    2011-10-01

    Structural, optical and magnetic studies have been carried out for the Co-doped ZnO nanoparticles (NPs). ZnO NPs are doped with 3% and 5% Co using ball milling and ferromagnetism (FM) is studied at room temperature and above. A high Curie temperature (Tc) has been observed from the Co doped ZnO NPs. X-ray diffraction and high resolution transmission electron microscopy analysis confirm the absence of metallic Co clusters or any other phase different from würtzite-type ZnO. UV-visible absorption and photoluminescence studies on the doped samples show change in band structure and oxygen vacancy defects, respectively. Micro-Raman studies of doped samples shows defect related additional strong bands at 547 and 574 cm(-1) confirming the presence of oxygen vacancy defects in ZnO lattice. The field dependence of magnetization (M-H curve) measured at room temperature exhibits the clear M-H loop with saturation magnetization and coercive field of the order of 4-6 emu/g and 260 G, respectively. Temperature dependence of magnetization measurement shows sharp ferromagnetic to paramagnetic transition with a high Tc = 791 K for 3% Co doped ZnO NPs. Ferromagnetic ordering is interpreted in terms of overlapping of polarons mediated through oxygen vacancy defects based on the bound magnetic polaron (BMP) model. We show that the observed FM data fits well with the BMP model involving localised carriers and magnetic cations.

  9. Maria Sklodowska-Curie - scientist, friend, manager

    Science.gov (United States)

    Slavchev, A.

    2009-01-01

    Great names in science represent an inexhaustible source and richness of inspiration, satisfaction and consolation, a moving and victorious force. Throughout her exemplifying life, Maria Sklodowska remained modest but with a keen sense of humor, of an outstanding style, a mine of knowledge and experience, of innovative ideas and a rich inner life. Full of love, of passion to give and to share, of natural optimism, mixed with a light melancholy, so typical for sages. She vehemently defended the love of scientific research, of the spirit of adventure and entrepreneurship and fought for international culture, for the protection of personality and talent. Maria Sklodowska left her passion to science, her dedication to work including education and training of young people, her passionate adherence to her family, her belief in her friends, her pure and profound humanity and warmth! The paper should be a homage to her, an appreciation of her work over the years, but not less a correspondence, a conversation with her! On the other hand, the present solemn occasion resuscitates the personalities of Maria and Pierre Curie and their work, in particular of Maria Sklodowska in her own native land! In this manner, it truly contributes to her immortality!

  10. Thermal expansion of gadolinium in the vicinity of the Curie point. [270 to 320/sup 0/K, Curie point exponents

    Energy Technology Data Exchange (ETDEWEB)

    Dolejsi, D.A.

    1977-02-01

    The c- and a-axis linear thermal expansivities of high purity single crystals of gadolinium were measured in the temperature range 270/sup 0/K to 320/sup 0/K. Length changes were translated to capacitance changes with a modified normal geometry 3-terminal capacitance dilatometer. An ac 3-terminal capacitance bridge was employed to measure nominal 10 pF capacitances to a precision of 10/sup -7/ pF, which corresponds to a relative length change sensitivity of 10/sup -10/. A 25 ohm platinum resistance thermometer was used to detect the dilatometer temperature to a precision of 10 ..mu..K with an ac resistance bridge. The c-axis expansivity was negative and had a large (approximately equal to 10/sup -4/ K/sup -1/) peak at 293.435/sup 0/K, while the a-axis expansivity was positive and had a smaller (approximately equal to 10/sup -5/ K/sup -1/) peak at 293.363/sup 0/K. The values of the Curie temperatures (T/sub c/'s) and critical point exponents for the c- and a-axis crystals were obtained from fitting power law equations to the expansivities.

  11. Experimental (155 K) and predicted (151 K) Curie temperature (T[sub c]) of K[sub 2]ZnBr[sub 4]: structural confirmation of ferroelectric state below T[sub c

    Energy Technology Data Exchange (ETDEWEB)

    Abrahams, S.C. (Physics Dept., Southern Oregon State Coll., Ashland, OR (United States))

    1994-04-01

    The temperature T[sub c] at which K[sub 2]ZnBr[sub 4] is predicted to transform from the paraelectric to the ferroelectric phase is 151 (19) K, based on the crystal structure determinations at 291 and 144 K by Fabry, Breczewski, Zuniga and Arnaiz and the Abrahams-Kurtz-Jamieson relationship. A dielectric and heat-capacity anomaly in this material at 155 K has been reported elsewhere. The locations reported for the ZnBr[sup 2-][sub 4] and K[sup +] ions fulfill the requirements of mirror plane symmetry above T[sub c]; ionic displacements along the polar direction that approach but do not exceed 0.1 A and that violate the mirror symmetry on cooling through T[sub c] form the basis of the prediction and satisfy the structural criteria for ferroelectricity in the phase below the transition. (orig.).

  12. Curie depth vs. flat subduction in Central Mexico

    Science.gov (United States)

    Manea, Marina; Constantin Manea, Vlad

    2010-05-01

    Forearcs located above active subduction zones are generally characterized by low heat flow values, and this is considered a consequence of the subduction of cold slabs beneath continental plates. In the case of Central Mexico, the geometry of the subducting Cocos plate is quite unusual, the slab runs flat for several hundreds of kilometers before plunging into the asthenosphere. This particular geometry has a strong influence on the temperature distribution of the overriding plate where very low heatflow values are recorded (15-30 mW/m2). In this paper we use the aeromagnetic map of Mexico in order to infer the maximum depth of magnetic source, regarded as Curie depth and corresponding to a temperature of 575-600C°. Our spectral analysis revealed the existence of a deep magnetic source (30-40 km). We compare these results with the thermal structure associated with flat slab subduction in the area. We obtained a good agreement between the two estimates and we conclude that flat slab subduction in Central Mexico controls the maximum depth of magnetic sources in the overriding plate.

  13. High-Tc Superconductivity: Strong Indication of Filamentary-Chaotic Conductance and Possible Routes to Superconductivity Above Room Temperature

    CERN Document Server

    Otto, Hans Hermann

    2016-01-01

    The empirical relation of T_co(K)=2740/_c^4 between the transition temperature of optimum doped superconductors T_co and the mean cationic charge _c, a physical paradox, can be recast to strongly support fractal theories of high-T_c superconductors, thereby applying the finding that the optimum hole concentration of h^+ = 0.229 can be linked with the universal fractal constant delta_1 = 8.72109... of the renormalized Henon map. The transition temperature obviously increases steeply with a domain structure of ever narrower size, characterized by Fibonacci numbers. With this backing superconductivity above room temperature can be conceived for synthetic sandwich structures of _c less than 2+. For instance, composites of tenorite and cuprite respectively tenorite and CuI (CuBr, CuCl) onto AuCu alloys are proposed. This specification is suggested by previously described filamentary superconductivity of 'bulk' CuO_1-x samples. In addition, cesium substitution in the Tl-1223 compound is an option. A low mean cation...

  14. Structure determination at room temperature and phase transition studies above $T_c$ in ABi4Ti4O15 (A = Ba, Sr or Pb)

    Indian Academy of Sciences (India)

    G Nalini; T N Guru Row

    2002-08-01

    The room temperature structure of three compounds belonging to the Aurivillius family ( = 4), ABi4Ti4O15 (A = Ba, Sr or Pb) has been analysed. BaBi4Ti4O15 crystallizes in a tetragonal 4/ space group whereas SrBi4Ti4O15 and PbBi4Ti4O15 crystallize in the orthorhombic space group $A2_1am$. The starting model for the Sr and Pb analogues was derived from ab initio methods and refined using the Rietveld method. The cations Ba and Sr are disordered over the Bi sites while the Pb cation is found exclusively in the [Bi2O2]2+ layers. The TiO6 octahedra are tilted with the Ti–O bonds forming zigzag chains along the `’ axis. The displacement of Bi atoms along the `’ axis might be responsible for ferroelectricity in these compounds. The high temperature X-ray data above $T_c$ indicate no structural transition for A = Ba and Pb while A = Sr transforms to the tetragonal structure.

  15. A bust of Marie Sklodowska Curie at CERN

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    The Polish Deputy Minister of Energy and Nuclear Power, J. Felicki, presented the Directors General with a bust of Mme Marie Sklodowska Curie on behalf of physicists of Poland (CERN Courier 19 (1979) 164).

  16. Marie Curie's Doctoral Thesis: Prelude to a Nobel Prize.

    Science.gov (United States)

    Wolke, Robert L.

    1988-01-01

    Traces the life and research techniques of Marie Curie's doctoral dissertation leading to the discovery and purification of radium from ore. Reexamines the discoveries of other scientists that helped lead to this separation. (ML)

  17. A jolly good call for Marie Curie Fellows

    CERN Multimedia

    2009-01-01

    A new funding opportunity to train young researchers has just been announced by the European Commission. One of the calls within FP7 Marie Curie Actions requests proposals for Initial Training Network (ITN) projects, with a deadline of 22 December 2009. Project proposals are strongly encouraged at CERN and authors can receive support and guidance from the Marie Curie Steering Group. Winnie Wong: "I wouldn’t have considered a PhD if I hadn’t been a Marie Curie fellow" Dan Savu: "It’s the best of both worlds: training plus working in an international organisation" ITN projects have one key aim: training. Academic and industrial partners work together to form a network to recruit and train Marie Curie Fellows. Fellows are young researchers (typically PhD-level) from any country who combine project-based research with tailor-made training programmes, ...

  18. The Pasteurization of Marie Curie: A (meta)biographical experiment.

    Science.gov (United States)

    Wirtén, Eva Hemmungs

    2015-08-01

    Biographies of scientists occupy a liminal space, highly popular with general readers but questioned in academia. Nonetheless, in recent years, historians of science have not only embraced the genre with more enthusiasm and less guilt, they have also turned to the metabiography in order to renew the study and story of scientists' roles. This essay focuses on Marie Curie, the world's most famous female scientist, in order to unpack some of the theoretical and methodological claims of the science biography, and especially to address the sexing mechanisms at play in the construction of the biographical subject. Pierre Curie (1923), Marie's biography of her husband Pierre, paid tribute to her dead husband and collaborator, but also allowed Curie a legitimate outlet to construct her own persona and legacy. Categories such as personhood, person, and persona are not only central to the biography genre but also are essential to the sense of self and self-fashioning of scientists. Looking at how Marie Curie negotiated these categories in Pierre Curie not only gives new insight into Curie's self-fashioning strategies but may also shed some light on the more general analytical lacunae of the science biography.

  19. Referrals to the Marie Curie nursing service in North Yorkshire.

    Science.gov (United States)

    Hanratty, B; Feather, J; Ward, C

    2000-01-01

    District and Marie Curie nurses participated in a small-scale study to describe referrals to a Marie Curie service in one English health district over a 3-month period. The number of new patients referred was small; they were geographically clustered and had widely differing life expectancies. Anecdotal reports of difficulties with the 'Nurselink' referral system were not confirmed, and in situations where the system was in operation, Marie Curie nurses were more likely to speak directly to the referring nurse. The most frequently cited reason for referral was general nursing needs; however, Marie Curie nurses felt that they were most often involved to provide family support. These findings suggest that there may not be a shared understanding of the Marie Curie nurse's role, and that equity in community palliative nursing care merits examination. Defining and publicizing the role of the Marie Curie nurse, providing guidance for referrals and prioritizing communication between professionals are proposed not only to enhance the service locally but to ensure that the service is available to all. This article illustrates the value of research to identify ways to improve service delivery.

  20. Temperature dependence of the upper critical field of high- Tc superconductors from isothermal magnetization data: influence of a temperature dependent Ginzburg-Landau parameter

    Science.gov (United States)

    Landau, I. L.; Ott, H. R.

    2003-11-01

    We show that the scaling procedure, recently proposed for the evaluation of the temperature variation of the normalized upper critical field of type-II superconductors, may easily be modified in order to take into account a possible temperature dependence of the Ginzburg-Landau parameter κ. As an example we consider κ( T) as it follows from the microscopic theory of superconductivity.

  1. Ferromagnetism from Co-Doped ZnO Nanocantilevers above Room Temperature

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shao-Min; WANG Peng; LI Sheng; ZHANG Bin; GONG He-Chun; DU Zu-Liang

    2008-01-01

    @@ At low temperature (400° C), chemical vapour deposition (CVD) is employed to make comb-like Co-doped ZnO nanocantilever arrays (NAs). The magnetization curves of the as-synthesized Co-doped ZnO NAs indicate the existence of above-room-temperature ferromagnetism (ARTFM) (Curie temperature, Tc > 300 K) whereas un-doped ZnO NAs does not. The corresponding ferromagnetic source mechanism is discussed, in which defects play an important role due to the strong green light emission.

  2. Marie and Irene Curie. The first female Nobel Prize winners; Marie en IreneCurie. De eerste vrouwelijke Nobelprijswinnaars

    Energy Technology Data Exchange (ETDEWEB)

    Noordenbos, G. [Joke Smit Instituut voor Vrouwenstudies, Universiteit Leiden, Leiden (Netherlands)

    2003-07-01

    Marie Curie was awarded the Nobel Prize in 1903 and in 1911. Also her daughter, Irene Joliot-Curie, received a Nobel Prize for science in 1935. In this book an overview is given of the academic world at that time: limited access to universities for women, the carriers of both women in physics and their pioneering research and discoveries, the refusal of Marie Curie by the French Academy of Sciences, the awarding of the Nobel Prize and the assignment of Irene Joliot-Curie as the first female minister in France, the impact of the two World Wars, their married and private lives and the constant smear campaign of the press against both women. The lives and works of both women are hold against the light of the present position of women in physical sciences. [Dutch] In 1903, precies honderd jaar geleden, ontving Marie Curie als eerste vrouw de Nobelprijs voor de Wetenschap, gevolgd door een tweede Nobelprijs in 1911. Ook haar dochter Irene Joliot-Curie kreeg de Nobelprijs voor de wetenschap in 1935. Marie and Irene Curie schetst een breed beeld van de academische wereld waarin beide vrouwen zich bewogen: de beperkte toegang van vrouwen tot de universiteit, hun carrisres in de natuurkunde en baanbrekende ontdekkingen, de afwijzing van Marie door de Franse Academie des Sciences, de toekenning van de Nobelprijs en de benoeming van Irene als eerste vrouwelijke minister in Frankrijk, de invloed van de twee Wereldoorlogen, hun huwelijks- en priveleven en de niet aflatende hetze van de pers tegen beiden. In de door mannen gedomineerde wereld van de natuurwetenschappen liep de uitzonderingspositie van beide vrouwen als rode draad door hun curieuze levens. Het leven en werk van de Curies wordt geactualiseerd door deze tegen het licht te houden van de huidige positie van vrouwen in de natuurwetenschappen. Het bereiken van de top van de wetenschap door vrouwen blijkt nog steeds uitzonderlijk.

  3. Joliot-Curie School of Nuclear Physics, 1997; Ecole Joliot-Curie de Physique Nucleaire, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, Y. [L`Institut National de Physique Nucleaire et de Physique des Particules du CNRS (India2P3), 75 - Paris (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    This document contains the lectures of the Joliot-Curie International School of Nuclear Physics held at Maubuisson, France on 8-13 September 1997. The following lectures of nuclear interest were given: The N-body problem (relativistic and non-relativistic approaches); The shell model (towards a unified of the nuclear structure); Pairing correlations in extreme conditions; Collective excitations in nuclei; Exotic nuclei (production, properties and specificities); Exotic nuclei (halos); Super and hyper deformation (from discrete to continuum, from EUROGAM to EUROBALL); and The spectroscopy of fission fragments. Important new facts are reported and discussed theoretically, concerning the nuclei in high excitation and high states and of the nuclei far off stability. Important technical achievements are reported among which the production of radioactive beams, sophisticated multi-detectors as well as significant advances in the nuclear theoretical methods. The double goal of training of young researchers and of permanent formation and information of the older ones seems to have been reached

  4. Anomalous curie response of impurities in quantum-critical spin-1/2 Heisenberg antiferromagnets.

    Science.gov (United States)

    Höglund, Kaj H; Sandvik, Anders W

    2007-07-13

    We consider a magnetic impurity in two different S=1/2 Heisenberg bilayer antiferromagnets at their respective critical interlayer couplings separating Néel and disordered ground states. We calculate the impurity susceptibility using a quantum Monte Carlo method. With intralayer couplings in only one of the layers (Kondo lattice), we observe an anomalous Curie constant C*, as predicted on the basis of field-theoretical work [S. Sachdev, Science 286, 2479 (1999)10.1126/science.286.5449.2479]. The value C* = 0.262 +/- 0.002 is larger than the normal Curie constant C=S(S+1)/3. Our low-temperature results for a symmetric bilayer are consistent with a universal C*.

  5. Ising Critical Behavior of Inhomogeneous Curie-Weiss Models and Annealed Random Graphs

    Science.gov (United States)

    Dommers, Sander; Giardinà, Cristian; Giberti, Claudio; van der Hofstad, Remco; Prioriello, Maria Luisa

    2016-11-01

    We study the critical behavior for inhomogeneous versions of the Curie-Weiss model, where the coupling constant {J_{ij}(β)} for the edge {ij} on the complete graph is given by {J_{ij}(β)=β w_iw_j/( {sum_{kin[N]}w_k})}. We call the product form of these couplings the rank-1 inhomogeneous Curie-Weiss model. This model also arises [with inverse temperature {β} replaced by {sinh(β)} ] from the annealed Ising model on the generalized random graph. We assume that the vertex weights {(w_i)_{iin[N]}} are regular, in the sense that their empirical distribution converges and the second moment converges as well. We identify the critical temperatures and exponents for these models, as well as a non-classical limit theorem for the total spin at the critical point. These depend sensitively on the number of finite moments of the weight distribution. When the fourth moment of the weight distribution converges, then the critical behavior is the same as on the (homogeneous) Curie-Weiss model, so that the inhomogeneity is weak. When the fourth moment of the weights converges to infinity, and the weights satisfy an asymptotic power law with exponent {τ} with {τin(3,5)}, then the critical exponents depend sensitively on {τ}. In addition, at criticality, the total spin {S_N} satisfies that {S_N/N^{(τ-2)/(τ-1)}} converges in law to some limiting random variable whose distribution we explicitly characterize.

  6. Properties of magnetocaloric materials with a distribution of Curie temperatures

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Bjørk, Rasmus; Smith, Anders;

    2012-01-01

    magnetic entropy change, Δs, and the heat capacity, cp, in zero magnetic field and an applied magnetic field of , have been calculated using the mean field model of ferromagnetism. Interestingly, both the peak position and amplitude of each of these parameters vary differently with the width...

  7. Observation of Curie transition during spark plasma sintering of ferromagnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Mani, Mahesh [Wolfson Centre for Magnetics, Cardiff School of Engineering, Cardiff University (United Kingdom); Viola, Giuseppe [School of Engineering and Materials Science, Queen Mary University of London (United Kingdom); Nanoforce Technology Ltd., London (United Kingdom); Hall, Jeremy P. [Wolfson Centre for Magnetics, Cardiff School of Engineering, Cardiff University (United Kingdom); Grasso, Salvatore; Reece, Mike J. [School of Engineering and Materials Science, Queen Mary University of London (United Kingdom); Nanoforce Technology Ltd., London (United Kingdom)

    2015-05-15

    The possibility of employing the ferromagnetic–paramagnetic phase transitions of magnetic materials to calibrate temperature during spark plasma sintering (SPS) was investigated using pure Fe and Fe–50Co alloy. A sharp and repeatable change was observed in the electrical current profile at the Curie temperature (T{sub c}) during both sintering and reheating of the sintered samples. Under a pulsed DC current, an abrupt change in the electrical resistance was observed at T{sub c} due to the sudden changes in the permeability and in turn, the skin depth during heating and cooling. These effects can be used to obtain a more accurate in-situ measurement of the sample temperature than the one provided by the pyrometers that are normally used for SPS processing. The temperature measured using a pyrometer was found to be significantly lower (up to 70 °C) than the actual temperature of the specimen. - Highlights: • Calibration of temperature during spark plasma sintering (SPS) remains a big challenge. • Temperature measured by non-contact pyrometers in SPS is not accurate. • Ferromagnetic materials exhibit abrupt change in permeability at Curie temperature (T{sub c}). • Iron and Fe–Co alloy showed sharp and reproducible changes in SPS electric current profiles at T{sub c}. • Ferromagnetic materials can be successfully used to calibrate pyrometers in SPS.

  8. GASIFICATION TEST RUN TC06

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services, Inc.

    2003-08-01

    This report discusses test campaign TC06 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC06. Test run TC06 was started on July 4, 2001, and completed on September 24, 2001, with an interruption in service between July 25, 2001, and August 19, 2001, due to a filter element failure in the PCD caused by abnormal operating conditions while tuning the main air compressor. The reactor temperature was varied between 1,725 and 1,825 F at pressures from 190 to 230 psig. In TC06, 1,214 hours of solid circulation and 1,025 hours of coal feed were attained with 797 hours of coal feed after the filter element failure. Both reactor and PCD operations were stable during the test run with a stable baseline pressure drop. Due to its length and stability, the TC06 test run provided valuable data necessary to analyze long-term reactor operations and to identify necessary modifications to improve equipment and process performance as well as progressing the goal of many thousands of hours of filter element exposure.

  9. Effect of double glow plasma surface chromizing on high-temperature oxidation resistance of TC4 titanium alloy%TC4合金双辉等离子渗Cr高温氧化行为

    Institute of Scientific and Technical Information of China (English)

    魏东博; 张平则; 姚正军; 梁文萍; 缪强; 徐重

    2011-01-01

    Isothermal oxidation behavior of TC4 titanium alloy,which was chromized by the double glow plasma surface alloying technology(DGP),were investigated at 650 ℃,750 ℃ and 850 ℃.The results show that the chromizing layer consists of surface loose layer,compact deposited layer and Ti-Cr mutual diffusion layer.The diffusion layer has better oxidation resistance compared with NiCrAlY thermal barrier coating.The ratio of Cr to Ti content in the diffusion layer exhibits gradient distribution by Cr,Cr1.97Ti1.07 and CrTi4.Under oxidation circumstance,Cr,Ti and Al diffuse outward to form multilayer oxide films,which prevent inward diffusion of oxygen.At 650 ℃,the oxidation films consist of two layers: the external Cr2O3 layer and the internal TiO2 layer.At 750 ℃,a mixed oxide layer containing Cr2O3 and TiO2 is formed beneath the Cr2O3 layer and TiO2 layer,whereby Ti(Cr,Al)2 Laves phase is observed in the Ti-depleted layer.At 850 ℃,a mixed oxide layer containing TiO2,Ti2O3 and Ti3O5 is formed beneath the Cr2O3 layer and Al2O3 layer,whereby Ti(Cr,Al)2 Laves phase and Kirkendall voids are formed in the depletion layer.%研究了双层辉光等离子渗Cr对TC4合金650、750、850℃恒温氧化性能的影响。结果表明:渗Cr后,表面梯度合金层显著提高了TC4合金的高温氧化性能,Ti-Cr互扩散层可有效阻止氧向基体扩散。氧化过程中,Ti、Cr向外扩散形成TiO2/Cr2O3氧化膜,其形态与氧化温度有关。850℃氧化100 h后,渗Cr试样表面形成致密Cr2O3膜,恒温氧化性能优于NiCrAlY热障涂层。

  10. Maria Sklodowska Curie - the precursor of radiation sterilization methods

    Energy Technology Data Exchange (ETDEWEB)

    Gluszewski, Wojciech; Zagorski, Zbigniew P. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Tran, Quoc Khoi; Cortella, Laurent [CEA Grenoble, ARC-Nucleart, Atelier Regional de Conservation, Grenoble (France)

    2011-06-15

    A resolution of the 63rd Assembly of the United Nations proclaimed the year 2011 as the International Year of Chemistry. The coordinators of the event are UNESCO and the International Union of Pure and Applied Chemistry (IUPAC). The patroness of this event is Marie Curie, nee Sklodowska. Among women scientists, she was the first recipient of the Novel Prize, and among all scientists, she is the only one who has received this award in different scientific fields (in 1903 in the field of physics with Pierre Curie and Henri Becquerel, in 1911 in the field of chemistry). Considering the former Polish nationality of Marie Curie, the year 2011 has been proposed by the Polish Parliament as her year, using the name Maria Sklodowska Curie, under which she is known in Poland. Celebrating the International Year of Chemistry is a good opportunity to remember the importance of the work of Maria Sklodowska Curie for the emergence and development of many fields of science. This article is an attempt to present a view of science, as taught through modern applications of the radiation chemistry of polymetric materials and radiation sterilization. Although the real development of both ''cold'' sterilization and polymer technology occurred in the 1950's long after the death of Marie Curie Sklodowska, the original ideas go back to ther work performed in the 1920s. Sometimes, and that is the present case, a single scientist creates a new field, in spite of the fact that at the time of discovery there are no applications. The parallel development of other branches of science and technology helps the application of the original idea. (orig.)

  11. PARTNER: A Marie Curie Initial Training Network for hadron therapy

    CERN Document Server

    CERN BULLETIN; Nathalie Hospital; Manuela Cirilli

    2011-01-01

    PARTNER is a 4-year Marie Curie Training project funded by the European Commission with 5.6 million Euros aimed at the creation of the next generation of experts. Ten academic institutes and research centres and two leading companies are participating in PARTNER, that is coordinated by CERN, forming a unique multidisciplinary and multinational European network.

  12. Critical Behavior of Thermal Expansion and Magnetostriction in the Vicinity of the First order transition at the Curie Point of Gd5(SixGe1-x)4

    Energy Technology Data Exchange (ETDEWEB)

    Mangui Han

    2004-12-19

    Thermal expansion (TE) and magnetostriction (MS) measurements have been conducted for Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} with a series of x values to study its critical behavior in the vicinity of transition temperatures. It was found that the Curie temperature of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} for x 0 {approx} 0.5 is dependent on magnetic field, direction of change of temperature (Tc on cooling was lower than Tc on heating), purity of Gd starting material, compositions, material preparation methods, and also can be triggered by the external magnetic field with a different dT/dB rate for different x values. For Gd{sub 5}(Si{sub 1.95}Ge{sub 2.05}), Gd{sub 5}(Si{sub 2}Ge{sub 2}), Gd{sub 5}(Si{sub 2.09}Ge{sub 1.91}), it was also found that the transition is a first order magneto-structural transition, which means the magnetic transition and crystalline structure transition occur simultaneously, and completely reversible. Temperature hysteresis and phase coexistence have been found to confirm that it is a first order transformation. While for Gd{sub 5}(Si{sub 0.15}Ge{sub 3.85}), it is partially reversible at some temperature range between the antiferromagnetic and the ferromagnetic state. For Gd{sub 5}(Si{sub 2.3}Ge{sub 1.7}) and Gd{sub 5}(Si{sub 3}Ge{sub 1}), it was a second order transformation between the paramagnetic and ferromagnetic state, because no {Delta}T have been found. Giant magnetostriction was only found on Gd{sub 5}(Si{sub 1.95}Ge{sub 2.05}), Gd{sub 5}(Si{sub 2}Ge{sub 2}), Gd{sub 5}(Si{sub 2.09}Ge{sub 1.91}) in their vicinity of first order transformation. MFM images have also been taken on polycrystal sample Gd{sub 5}(Si{sub 2.09}Ge{sub 1.91}) to investigate the transformation process. The results also indicates that the Curie temperature was lower and the thermally-induced strain higher in the sample made from lower purity level Gd starting materials compared with the sample made from high purity Gd metal. TE, MS, MFM and VSM measurements

  13. Structural changes of high-Tc superconductors under pressures up to 29 GPa and at temperatures between 15 and 300 K

    Science.gov (United States)

    Fietz, W. H.; Wassilew, C. A.; Ludwig, H. A.; Obst, B.; Dietrich, M. R.

    1990-05-01

    Structural changes in the high-Tc superconductors YbBa2Cu3O7 (Yb-123) and Yb2BaCuO5 (Yb-211) with increasing pressure are studied using self-focusing X-ray equipment with a position-sensitive detector. The results show that Yb-123 has a bulk modulus of 155 GPa with linear compressibilities beta(a) = 0.0013/GPa, beta(b) = 0.0015/GPa, and beta(c) = 0.0033/GPa. The bulk modulus of superconducting Yb-211 is 170 GPa. Similar measurements on several other high-Tc superconductors and related materials show a systematic decrease of the bulk modulus of high-Tc superconductors when going from materials closely related to perovskite to materials with an extremely degenerated perovskite structure. This change is mainly caused by a change of the linear compressibility in the c-axis direction. The linear compressibilities in the a and b directions are similar for all these materials.

  14. The legacy of Maria Curie Skłodowska

    Science.gov (United States)

    Sosnowski, Ryszard

    2011-01-01

    Maria Skłodowska Curie left us a great legacy. Her discovery of polonium and radium was incomparably greater than the mere discovery of new elements. Its significance lay in the discovery of a new form of matter, namely radioactive one, but also in her unveiling of the internal property of its atoms. Subsequently emitted radiation went on to play the role of a "natural accelerator" for both scientific research and in medical radiotherapy. It was thanks to these discoveries that the field of nuclear physics arose just a few decades later. As importantly the work of Maria Curie Skłodowska during the Great War demonstrated how important pure scientific discovery can be for society and its welfare.

  15. Special Workshop of Marie Curie Fellows on Research and Training in Physics and Technology

    CERN Document Server

    Patrice Loiez

    2002-01-01

    Photo 0210004_1: Prof. Ugo Amaldi, University of Milano Bicocca and Tera Foundation, Italy. Addressing the Marie Curie Workshop held at CERN 3-4 October 2002. Title of this talk:"Research Developments on Medical Physics". Photo 0210004_2: Marie Curie Fellows at CERN. Participating in Marie Curie Workshop held at CERN 3-4 October 2002.

  16. Investigation on Tc tuned nano particles of magnetic oxides for hyperthermia applications.

    Science.gov (United States)

    Giri, Jyotsnendu; Ray, Amlan; Dasgupta, S; Datta, D; Bahadur, D

    2003-01-01

    Superparamagnetic as well as fine ferrimagnetic particles such as Fe3O4, have been extensively used in magnetic field induced localized hyperthermia for the treatment of cancer. The magnetic materials with Curie temperature (Tc) between 42 and 50 degrees C, with sufficient biocompatibility are the best candidates for effective treatment such that during therapy it acts as in vivo temperature control switch and thus over heating could be avoided. Ultrafine particles of substituted ferrite Co(1-a)Zn(a)Fe2O4 and substituted yttrium-iron garnet Y3Fe(5-x)Al(x)O12 have been prepared through microwave refluxing and citrate-gel route respectively. Single-phase compounds were obtained with particle size below 100 nm. In order to make these magnetic nano particles biocompatible, we have attempted to coat these above said composition by alumina. The coating of alumina was done by hydrolysis method. The coating of hydrous aluminium oxide has been done over the magnetic particles by aging the preformed solid particles in the solution of aluminium sulfate and formamide at elevated temperatures. In vitro study is carried out to verify the innocuousness of coated materials towards cells. In vitro biocompatibility study has been carried out by cell culture method for a period of three days using human WBC cell lines. Study of cell counts and SEM images indicates the cells viability/growth. The in vitro experiments show that the coated materials are biocompatible.

  17. Exhibition: Life and Achievements of Maria Sklodowska-Curie

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The exhibition "Life and Achievements of Maria Sklodowska-Curie” will be held at CERN (Pas Perdus Corridor, 1st floor, building 61) from the 8 to 24 March.   It is organised under the auspices of the Ambassador R. Henczel, Permanent Representative of the Republic of Poland to the UN Office at Geneva to celebrate the 100th anniversary of the Nobel Prize in Chemistry given to Maria Sklodowska-Curie. The exhibition is also one of the events celebrating the 20th anniversary of Poland joining CERN as a Member State. Maria Sklodowska-Curie, Nobel Prize winner both in physics and chemistry, is one of the greatest scientists of Polish origin. The exhibition, consisting of 20 posters, presents her not only as a brilliant scientist, but also an exceptional woman of great heart, character and organizational talents, sensitive to contemporary problems. The authors are Mrs M. Sobieszczak-Marciniak, the director of the Maria Sklodowska-Curie Museum in Warsaw and Mrs H. Krajewska, the direct...

  18. The contribution of women to radiobiology: Marie Curie and beyond.

    Science.gov (United States)

    Gasinska, Anna

    2016-01-01

    Marie Sklodowska-Curie, an extraordinary woman, a Polish scientist who lived and worked in France, led to the development of nuclear energy and the treatment of cancer. She was the laureate of two Nobel Prizes, the first woman in Europe who obtained the degree of Doctor of Science and opened the way for women to enter fields which had been previously reserved for men only. As a result of her determination and her love of freedom, she has become an icon for many female scientists active in radiation sciences. They are successors of Maria Curie and without the results of their work, improvement in radiation oncology will not be possible. Many of them shared some elements of Maria Curie's biography, like high ethical and moral standards, passionate dedication to work, strong family values, and scientific collaboration with their husbands. The significance of Tikvah Alper, Alma Howard, Shirley Hornsey, Juliana Denekamp, Helen Evans, Eleanor Blakely, Elizabeth L. Travis, Fiona Stewart, Andree Dutreix, Catharine West, Peggy Olive, Ingela Turesson, Penny Jeggo, Irena Szumiel, Eleonor Blakely, Sara Rockwell and Carmel Mothersill contribution to radiation oncology is presented. All the above mentioned ladies made significant contribution to the development of radiotherapy (RT) and more efficient cancer treatment. Due to their studies, new schedules of RT and new types of ionizing radiation have been applied, lowering the incidence of normal tissue toxicity. Their achievements herald a future of personalized medicine.

  19. New superconductors from granular to high T$_{c}$

    CERN Document Server

    Deutscher, Guy

    2006-01-01

    How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This book aims to give some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a maximum of their critical temperature near the metal-insulator transition.

  20. [Chronological table of Mr. and Mrs. Curie and Mr. and Mrs. Joliot-Curie--in connection with the 100-year anniversary since Dr. H. Becquerel discovered radial ray in 1896].

    Science.gov (United States)

    Yamada, M

    1996-01-01

    This year (1996) is the 100th year since Dr. Henri Becquerel discovered radial rays in 1896 in France. In 1897, Dr. Pierre Curie and Marie Curie preliminarily reported the existence of polonium and radium which have radioactivity. H. Becquerel, Pierre and Marie Curie were awarded the Nobel Chemical Prize for discovering artificial radioactivity in 1935. I report herein the chronological table of Mr. and Mrs. Curie and Mr. and Mrs. Joliot-Curie spanning about one century.

  1. Frederic Joliot-Curie: the scientist and politics; Frederic Joliot-Curie: le savant et la politique

    Energy Technology Data Exchange (ETDEWEB)

    Pinault, M

    2000-07-01

    This book presents the biography of the French scientist, founder of the French nuclear research, in its social, political, and scientific context. Frederic Joliot-Curie, with his wife Irene, discovered the artificial radioactivity in 1934, won the Nobel price of chemistry in 1935, and demonstrated the existence of the fission phenomenon. He studied the chain reactions and the conditions of realization of a nuclear reactor, called 'Zoe', which was built in 1948. He was the very first chief-commissary of the French atomic energy commission (CEA). (J.S.)

  2. Phase Transition in Conditional Curie-Weiss Model

    CERN Document Server

    Opoku, Alex A; Ansah, Richard

    2016-01-01

    This paper proposes a conditional Curie-Weiss model as a model for opinion formation in a society polarized along two opinions, say opinions 1 and 2. The model comes with interaction strength $\\beta>0$ and bais $h$. Here the population in question is divided into three main groups, namely: Group one consisting of individuals who have decided on opinion 1. Let the proportion of this group be given by $s$. Group two consisting of individauls who have chosen opinion 2. Let $r$ be their proportion. Group three consisting of individuals who are yet to decide and they will decide based on their environmental conditions. Let $1-s-r$ be the proportion of this group. We show that the specific magnetization of the associated conditional Curie-Weiss model has a first order phase transition (discontinuous jump in specific magnetization) at $\\beta^*=\\left(1-s-r\\right)^{-1}$. It is also shown that not all the discontinuous jumps in magnetization will result in phase change. We point out how an extention of this model could...

  3. Technetium Removal Using Tc-Goethite Coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Wang, Guohui; Jung, Hun Bok; Peterson, Reid A.

    2013-11-18

    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Low temperature waste forms coupled with technetium removal using an alternative immobilization process such as Fe(II) treated-goethite precipitation” to increase our understanding of 99Tc long-term stability in goethite mineral form and the process that controls the 99Tc(VII) reduction and removal by the final Fe (oxy)hydroxide forms. The overall objectives of this task were to 1) evaluate the transformation process of Fe (oxy)hydroxide solids to the more crystalline goethite (α-FeOOH) mineral for 99Tc removal and 2) determine the mechanism that limits 99Tc(IV) reoxidation in Fe(II)-treated 99Tc-goethite mineral and 3) evaluate whether there is a long-term 99Tcoxidation state change for Tc sequestered in the iron solids.

  4. Magneto-caloric effect of FexZryB100-x-y metallic ribbons for room temperature magnetic refrigeration

    Science.gov (United States)

    Guo, D. Q.; Chan, K. C.; Xia, L.; Yu, P.

    2017-02-01

    Among various amorphous magnetic materials, even though Fe-based materials do not have high magnetocaloric effect (MCE), their advantages of tunable Curie temperature (TC) and low cost have attracted considerable attention in regard to room temperature magnetic refrigeration applications. With the aim of enhancing the MCE, the influence of boron addition on Fe-based amorphous materials was investigated in this study. Fe94-xZr6Bx (x=5, 6, 8 and 10), Fe91-yZr9By (y=3, 4, 5, 6, 8 and 10) and Fe89-zZr11Bz (z=3, 4, 5, 6, 8 and 10) specimens were made in ribbon form and their magnetocaloric effect was investigated. The Curie temperature (TC) of all three series of ribbons underwent an almost linear increase, and the peak magnetic entropy change, | Δ SMpeak | (obtained in a magnetic field of 1.5 T), generally increases with increasing boron content. The results further show that the Fe86Zr9B5 ribbon exhibits a relatively large | Δ SMpeak | value of 1.13 J/kgK at 330 K and a large refrigerant capacity value of 135.6 J/kg under 1.5 T. On the basis of these results, although there is still much scope for improvement before totally replacing the conventional cooling method, the Fe-based amorphous ribbon can be seen as a promising magnetocaloric material for room temperature magnetic refrigeration applications.

  5. Impeding 99Tc(IV) mobility in novel waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Mal Soon; Um, Wooyong; Wang, Guohui; Kruger, Albert A.; Lukens, Wayne W.; Rousseau, Roger J.; Glezakou, Vassiliki Alexandra

    2016-06-30

    Technetium (99Tc) is a long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state1. Immobilization of Tc in mineral substrates is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels2, 3 has been proposed as a novel method to increase Tc retention in glass waste forms. However, experiments with Tc-magnetite under high temperature and oxic conditions showed re-oxidation of Tc(IV) to volatile pertechnetate Tc(VII)O4-.4, 5 Here we address this problem with large-scale ab initio molecular dynamics simulations and propose that elevated temperatures, 1st row transition metal dopants can significantly enhance Tc retention in the order Co > Zn > Ni. Experiments with doped spinels at T=700 ºC provided quantitative confirmation of increased Tc retention in the same order predicted by theory. This work highlights the power of modern state-of-the-art simulations to provide essential insights and generate bottom-up design criteria of complex oxide materials at elevated temperatures.

  6. Effect of temperature on rotational viscosity in magnetic nano fluids.

    Science.gov (United States)

    Patel, R

    2012-10-01

    Flow behavior of magnetic nano fluids with simultaneous effect of magnetic field and temperature is important for its application for cooling devices such as transformer, loud speakers, electronic cooling and for its efficiency in targeted drug delivery and hyperthermia treatment. Using a specially designed horizontal capillary viscometer, temperature-sensitive and non-temperature-sensitive magnetic nano fluids are studied. In both these case the temperature-dependent rotational viscosity decreases, but follows a quite different mechanism. For temperature-sensitive magnetic nano fluids, the reduction in rotational viscosity is due to the temperature dependence of magnetization. Curie temperature ((T)(c)) and pyromagnetic coefficient are extracted from the study. A fluid with low T(c) and high pyromagnetic coefficient is useful for thermo-sensitive cooling devices and magnetic hyperthermia. For non-temperature-sensitive magnetic nano fluids, reduction in rotational viscosity is due to removal of physisorbed secondary surfactant on the particle because of thermal and frictional effects. This can be a good analogy for removal of drug from the magnetic particles in the case of targeted drug delivery.

  7. Determination of the Thermal Decomposition Products of Terephthalic Acid by Using Curie-Point Pyrolyzer

    Science.gov (United States)

    Begüm Elmas Kimyonok, A.; Ulutürk, Mehmet

    2016-04-01

    The thermal decomposition behavior of terephthalic acid (TA) was investigated by thermogravimetry/differential thermal analysis (TG/DTA) and Curie-point pyrolysis. TG/DTA analysis showed that TA is sublimed at 276°C prior to decomposition. Pyrolysis studies were carried out at various temperatures ranging from 160 to 764°C. Decomposition products were analyzed and their structures were determined by gas chromatography-mass spectrometry (GC-MS). A total of 11 degradation products were identified at 764°C, whereas no peak was observed below 445°C. Benzene, benzoic acid, and 1,1‧-biphenyl were identified as the major decomposition products, and other degradation products such as toluene, benzophenone, diphenylmethane, styrene, benzaldehyde, phenol, 9H-fluorene, and 9-phenyl 9H-fluorene were also detected. A pyrolysis mechanism was proposed based on the findings.

  8. Aspectos históricos da visita de Marie Sklodowska Curie a Belo Horizonte

    Directory of Open Access Journals (Sweden)

    Cássius Klay Nascimento

    2011-01-01

    Full Text Available In the year 2011 it is celebrated the Marie Sklodowska Curie Nobel Prize centenary and the International Year of Chemistry. However, it is not generally known that Marie Sklodowska Curie, one of the greatest scientists of all time, visited Belo Horizonte, state of Minas Gerais, Brazil. She arrived by train at Belo Horizonte city on 16 August 1926, coming from Rio de Janeiro and accompanied by her daughter Irène Joliot-Curie. The scientists visited the Institute of Radium of Belo Horizonte. The approach in this work emphasizes the presence of Marie Sklodowska Curie in Belo Horizonte, exploring the admiration and respect that people had for her.

  9. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  10. Peculiar oxygen and copper isotope effects on the pseudogap formation temperature in underdoped to overdoped cuprates: Pseudogap induced by pairing correlations above Tc in cuprates with large and small Fermi surfaces

    Science.gov (United States)

    Dzhumanov, S.; Khudayberdiev, Z. S.; Djumanov, Sh. S.

    2015-05-01

    We investigate the pseudogap (PG) state and the peculiar oxygen and copper isotope effects on the PG onset temperature T* in cuprate superconductors with large and small Fermi surfaces within the polaron model and two different BCS-based approaches extended to the intermediate coupling regime. We argue that the unconventional electron-phonon interactions are responsible for the polaron formation and BCS-like pairing correlations above Tc in underdoped to overdoped cuprates, which are exotic (non-BCS) superconductors. Using the generalized BCS-like theory, we calculate pseudogap formation temperatures T*, isotope shifts ΔT*, oxygen and copper isotope exponents (i.e. αT*O and αT*Cu) and show that isotope effects on T* strongly depend on strengths of Coulomb and electron-phonon interactions, doping levels and dielectric constants of the cuprates. This theory explains the existence of small positive or sign reversed oxygen isotope effect, sizable and very large negative oxygen and copper isotope effects on T* in cuprates with large Fermi surfaces. Further, we use another version of the extended BCS-like model to study the PG formation and the peculiar isotope effects on T* in deeply underdoped cuprates with small Fermi surfaces and predict the existence of small and sizable negative oxygen and copper isotope effects on T* in such underdoped cuprates. The results for T*, isotope shifts ΔT* and exponents (αT*O and αT*Cu) in different classes of high-Tc cuprates are in good agreement with the existing well-established experimental data and explain the controversy between various experiments on isotope effects for T* in the cuprates.

  11. High-Tc superconducting quantum interference device recordings of spontaneous brain activity: Towards high-Tc magnetoencephalography

    Science.gov (United States)

    Öisjöen, F.; Schneiderman, J. F.; Figueras, G. A.; Chukharkin, M. L.; Kalabukhov, A.; Hedström, A.; Elam, M.; Winkler, D.

    2012-03-01

    We have performed single- and two-channel high transition temperature (high-Tc) superconducting quantum interference device (SQUID) magnetoencephalography (MEG) recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of two well-known brain rhythms: the occipital alpha rhythm and the mu rhythm found in the motor cortex. We further show that despite higher noise-levels compared to their low-Tc counterparts, high-Tc SQUIDs can be used to detect and record physiologically relevant brain rhythms with comparable signal-to-noise ratios. These results indicate the utility of high-Tc technology in MEG recordings of a broader range of brain activity.

  12. Special Workshop of Marie Curie Fellows on Research and Training in Physics and Technology

    CERN Multimedia

    Patrice Loiez

    2002-01-01

    Photo 0210006_07a: Prof. L. Maiani, Director General of CERN. Addressing the Marie Curie Worshop held at CERN 3-4 October 2002. Title of this talk:"Function of Large-scale Facilities and Centres of Excellence". Photo 0210006_14a: Prof. L. Maiani, Director General of CERN. Addressing the Marie Curie Worshop held at CERN 3-4 October 2002. Title of this talk:"Function of Large-scale Facilities and Centres of Excellence". Photo 0210006_22: Dr. David Plane (CERN) introducing Dr. Theodore Papazoglou from the European Commission. Addressing the Marie Curie Worshop held at CERN 3-4 October 2002. Title of this talk:"Marie Curie Fellowships in the 6th Framework Programme". Photo 0210006_28a: Dr. Nora Brambilla, Vice-President of Marie Curie Fellow Association, INFN and Dept. of Physics, University of Milan. Addressing the Marie-Curie Worshop held at CERN 3-4 October 2002. Title of this talk:"Marie Curie Fellows Association". Photo 0210006_29a: Dr. Nora Brambilla, Vice-President of Marie Curie Fellow Association, INFN a...

  13. Repeated magnetization with temperature control in a high-Tc superconducting bulk; Ondo seigyo wo tomonatta koon chodendo baaruku tai no dotai no kurikaeshi no chakuji ho

    Energy Technology Data Exchange (ETDEWEB)

    Kamijo, H.; Fujimoto, H. [Railway tech. Research Inst., Tokyo (Japan)

    2000-05-29

    It examines applicability of the hulk magnet which uses magnetize-ingly the high-temperature superconductivity bulk body to the superconducting magnet for levitation system railway. It must be magnetized to the superconductive bulk body in respect of as much as possible large magnetic flux in order to obtain the powerful bulk magnet. Therefore, large coil for the impression magnetic field and power are required, and there is a problem of the growth of large electromagnetic mosquito even in the magnetizing process. Then, it is trying the method for magnetizing large magnetic field to the superconductive bulk body by comparatively small impression magnetic field by the method for repeatedly carrying out field cool and pulse magnetizing, while it gradually lowers the temperature of the superconductive bulk body from the critical temperature. (NEDO)

  14. Temperature field driven polar nanoregions in KTa1-xNbxO3

    Science.gov (United States)

    Tan, Peng; Tian, Hao; Hu, Chengpeng; Meng, Xiangda; Mao, Chenyang; Huang, Fei; Shi, Guang; Zhou, Zhongxiang

    2016-12-01

    Correlated disorder, which exists more widely in materials than crystalline phases, is beneficial for the improvement of material properties. KTa1-xNbxO3 (KTN), a type of perovskite crystal, is recognized as a correlated disorder system in the vicinity of the Curie temperature, Tc, because of the existence of polar nanoregions (PNRs), which yield scale-free optics, reprogrammable soliton nonlinearity, and giant electro-optic effects. In this letter, we propose the mechanisms for induced PNR reorientation under a specific temperature field and manipulate PNRs using a temperature gradient in KTN to modulate light polarization, reduce light scattering, and enhance the electro-optic effect. A designed temperature gradient provides an effective way to drive correlated disordered PNRs, which could guide the exploitation of PNRs and is significant for correlated disorder applications.

  15. Marie Curie nurses: enabling patients with cancer to die at home.

    Science.gov (United States)

    Higginson, Irene J; Wilkinson, Susie

    2002-05-01

    Marie Curie Cancer Care established its nursing service in 1958; however, the service has had little formal evaluation. This study aimed to describe and evaluate the care provided by Marie Curie nurse, and in particular to determine whether patients in their care remained and died at home. Two existing data sets were used: data on all patients referred to the Marie Curie Nursing Services in 147 areas of England, Wales, Scotland and Northern Ireland for 26 months, and data on cancer death registrations in England. A request for a Marie Curie nurse was made for 26,632 patients, 97% of whom had cancer and 11% of whom lived alone. The amount of care provided varied enormously (Marie Curie nurses facilitated home death for many patients. Services need to ensure that mechanisms are in place to achieve data collection. Rigorous prospective evaluation is needed in the future.

  16. Critical Behavior of Thermal Expansion and Magnetostriction in the Vicinity of the First order transition at the Curie Point of Gd5(SixGe1-x)4

    Energy Technology Data Exchange (ETDEWEB)

    Han, Mangui [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Thermal expansion (TE) and magnetostriction (MS) measurements have been conducted for Gd5(SixGe1-x)4 with a series of x values to study its critical behavior in the vicinity of transition temperatures. It was found that the Curie temperature of Gd5(SixGe1-x)4 for x 0 ~ 0.5 is dependent on magnetic field, direction of change of temperature (Tc on cooling was lower than Tc on heating), purity of Gd starting material, compositions, material preparation methods, and also can be triggered by the external magnetic field with a different dT/dB rate for different x values. For Gd5(Si1.95Ge2.05), Gd5(Si2Ge2), Gd5(Si2.09Ge1.91), it was also found that the transition is a first order magneto-structural transition, which means the magnetic transition and crystalline structure transition occur simultaneously, and completely reversible. Temperature hysteresis and phase coexistence have been found to confirm that it is a first order transformation. While for Gd5(Si0.15Ge3.85), it is partially reversible at some temperature range between the antiferromagnetic and the ferromagnetic state. For Gd5(Si2.3Ge1.7) and Gd5(Si3Ge1), it was a second order transformation between the paramagnetic and ferromagnetic state, because no ΔT have been found. Giant magnetostriction was only found on Gd5(Si1.95Ge2.05), Gd5(Si2Ge2), Gd5(Si2.09Ge1.91) in their vicinity of first order transformation. MFM images have also been taken on polycrystal sample Gd5(Si2.09Ge1.91) to investigate the transformation process. The results also indicates that the Curie temperature was lower and the thermally

  17. Superplastic Deformation of TC6 Alloy

    Directory of Open Access Journals (Sweden)

    DING Ling

    2016-12-01

    Full Text Available The superplastic tensile tests of TC6 alloy were conducted in the temperature range of 800-900℃ by using the maximum m value superplasticity deformation (Max m SPD method and the constant strain rate deformation method at the strain rate range of 0.0001-0.1 s-1. The stress-strain curve of the tensile tests was obtained and the microstructure near the fracture were analyzed by metallographic microscope. The result shows that the superplasticity of TC6 alloy is excellent, and the elongation increases first and then decreases with the increase of strain rate or temperature. When the temperature is 850℃ and strain rate is 0.001 s-1 at constant stain rate tensile tests, the elongation reaches up to 993%. However, the elongation using Max m SPD method at 850℃ is 1353%. It is shown that the material can achieve better superplasticity by using Max m SPD tensile compared to constant stain rate tensile under the same temperature. The superplastic deformation of TC6 alloy can enhance the dynamic recrystallization behavior significantly, the dynamic recrystallization behavior is promoted when strain rate and temperature are increased.

  18. Impeding 99Tc(IV) mobility in novel waste forms

    Science.gov (United States)

    Lee, Mal-Soon; Um, Wooyong; Wang, Guohui; Kruger, Albert A.; Lukens, Wayne W.; Rousseau, Roger; Glezakou, Vassiliki-Alexandra

    2016-06-01

    Technetium (99Tc) is an abundant, long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state. Tc immobilization is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels has been proposed as a novel method to increase Tc retention in glass waste forms during vitrification. However, experiments under high-temperature and oxic conditions show reoxidation of Tc(IV) to volatile pertechnetate, Tc(VII). Here we examine this problem with ab initio molecular dynamics simulations and propose that, at elevated temperatures, doping with first row transition metal can significantly enhance Tc retention in magnetite in the order Co>Zn>Ni. Experiments with doped spinels at 700 °C provide quantitative confirmation of the theoretical predictions in the same order. This work highlights the power of modern, state-of-the-art simulations to provide essential insights and generate theory-inspired design criteria of complex materials at elevated temperatures.

  19. Special Workshop of Marie Curie Fellows on Research and Training in Physics and Technology.

    CERN Document Server

    Patrice Loiez

    2002-01-01

    Photo 0210008_05a: Dr, Rolf Landua (CERN) explaining to participants of the Marie Curie Workshop (held at CERN 3-4 October 2002) the ATHENA experiment and the Antiproton Decelerator. Photo 0210008_06a: Dr, Rolf Landua (CERN) explaining to participants of the Marie Curie Workshop (held at CERN 3-4 October 2002) the ATHENA experiment and the Antiproton Decelerator. Photo 0210008_08a: Dr, Rolf Landua (CERN) explaining to participants of the Marie Curie Workshop (held at CERN 3-4 October 2002) the ATHENA experiment and the Antiproton Decelerator. Photo 0210008_09a: Dr, Rolf Landua (CERN) explaining to participants of the Marie Curie Workshop (held at CERN 3-4 October 2002) the ATHENA experiment and the Antiproton Decelerator.

  20. Curie-point Depths Estimated from Fractal Magnetization Models in the Indian-Himalayan Region

    Science.gov (United States)

    Wang, J.; Li, C. F.; Lei, J., Sr.; Zhang, G.; Sun, C., Sr.

    2016-12-01

    The convergence between the Indian and Eurasian plates has developed the world's extreme topography and has also resulted in the occurrence of large earthquakes in the region. The April 25, 2015 (Mw 7.8) earthquake in central Nepal is the largest earthquake that has been recorded in the Nepal Himalaya since 1934. The earthquake caused thousands of people to die and massive destruction of famous heritage-structures in and around kathmandu and was attributed to the interations between the Indian and Eurasian plates. The crustal thermal structure which can be inferred from the Curie-point depths is critial to understand the seismotectonics and subduction in the Indian-Himalayan region. We present our inversion of Curie-point depths of the Indian-Himalayan region based on fractal spectral analyses both from aeromagnetic and satellite data. The first magnetic anomaly model used for estimatiion of Curie-point depths is the EMAG2 model, which has a resolution of 2-arc minute and an altitude of 4 km above the geoid. The second magnetic anomaly model is the CHAMP lithospheric model MF6. The third and the last magnetic anomaly model is the NGDC-720 lithospheric model, which is based on both the EMAG2 and MF6 models, has the smallest wavelength of 56 km. We first test variable windows sizes of 100.8×100.8 km2, 201.6×201.6 km2 and 302.4×302.4 km2 to estimate the Curie-point depths and then take the average of the results from these three different window sizes as the final Curie depths for the EMAG2 and MF6 models, respectively. The differences between the two Curie depths estimations from the EMAG2 and MF6 models mostly range within about ±4 km except for that in the Central Tibetan Plateau and Northeast India. This result shows that the NGDC-720 lithospheric model which contains both the EMAG2 and MF6 models is valid for the Curie-point estimation in the Indian-Himalayan region. The average Curie depths estimated from the NGDC-720 lithospheric model show small values in

  1. Room-temperature Ferroelectricity in Uniaxially Strained Single-crystalline SrTiO3 Freestanding Films

    Science.gov (United States)

    Lu, Di; Crossley, Sam; Yoon, Hyeok; Hikita, Yasuyuki; Hwang, Harold

    Single crystal pure bulk SrTiO3 (STO) is an incipient ferroelectric whose dielectric permittivity rises to high values as temperature is reduced, but remains paraelectric to the lowest observable temperatures. Ferroelectric phases of STO may be stabilized via doping and strain, whose common effect is to split the spatial free energy well of ionic displacements. With epitaxial strain of the order of a few percent, Curie temperatures TC ~293 K have been observed. By exploiting a highly novel process to exfoliate epitaxial oxide films deposited by pulsed laser deposition, we have isolated sub-100 nm-thick freestanding films of STO which are readily manipulated and mechanically strained to high levels. Measurements of the in-plane dielectric properties for various applied strains reveal a continuously tunable ferroelectric TC. A two-order-of-magnitude enhanced dielectric response is displayed by a 1.2%-strained sample at TC ~290 K, as compared with the same sample unstrained at the same temperature. This is consistent with a phenomenological Ginzburg-Landau model, and previous studies on anchored films. The functional properties of strained STO have generated intense interest and debate, and have been suggested for device applications due to e.g. high voltage-tunable dielectric properties. Our work exhibits strain as a continuously variable experimental degree of freedom, which can induce numerous functional effects.

  2. Cluster Mott insulators and two Curie-Weiss regimes on an anisotropic kagome lattice

    Science.gov (United States)

    Chen, Gang; Kee, Hae-Young; Kim, Yong Baek

    2016-06-01

    Motivated by recent experiments on the quantum-spin-liquid candidate material LiZn2Mo3O8 , we study a single-band extended Hubbard model on an anisotropic kagome lattice with the 1/6 electron filling. Due to the partial filling of the lattice, the intersite repulsive interaction is necessary to generate Mott insulators, where electrons are localized in clusters rather than at lattice sites. It is shown that these cluster Mott insulators are generally U(1) quantum spin liquids with spinon Fermi surfaces. The nature of charge excitations in cluster Mott insulators can be quite different from conventional Mott insulator and we show that there exists a cluster Mott insulator where charge fluctuations around the hexagonal cluster induce a plaquette charge order (PCO). The spinon excitation spectrum in this spin-liquid cluster Mott insulator is reconstructed due to the PCO so that only 1/3 of the total spinon excitations are magnetically active. Based on these results, we propose that the two Curie-Weiss regimes of the spin susceptibility in LiZn2Mo3O8 may be explained by finite-temperature properties of the cluster Mott insulator with the PCO as well as fractionalized spinon excitations. Existing and possible future experiments on LiZn2Mo3O8 , and other Mo-based cluster magnets are discussed in light of these theoretical predictions.

  3. Critical behavior near the ferromagnetic to paramagnetic phase transition temperature in polycrystalline La0.5Sm0.1Sr0.4Mn1-xInxO3 (0 ≤ x ≤ 0.1)

    Science.gov (United States)

    Dhahri, M.; Dhahri, J.; Hlil, E. K.

    2017-07-01

    In this paper we report on the critical analysis of the La0.5Sm0.1Sr0.4Mn1-xInxO3 (0 ⩽x ⩽ 0.1) manganites near the ferromagnetic-paramagnatic phase transition temperature. Various techniques such as modified Arrott plot, Kouvel-Fisher method and critical isotherm were used to analyze the magnetic-field dependence of magnetization. The Curie temperature (TC) could be tuned over a wide temperature range, from 251 K to 310 K, with varying in content. Though the nature of this transition is found to be of second order, the estimated critical exponents β, γ, and δ obtained for different values of x are close to the theoretically predicted values for the three-dimensional (3D)-Ising interaction model (β = 0.324 ± 0.01, γ = 1.240 ± 0.13 at TC = 310 K for x = 0.00); (β = 0.329 ± 0.04, γ = 1.241 ± 0.001 at TC = 294 K for x = 0.05); (β = 0.332 ± 0.01, γ = 1.250 ± 0.04 at TC = 251 K for x = 0.10) and are very far away from any other known universality class. The critical isotherm M (TC, μ0H) gives δ = 5.02 ± 0.01 for x = 0.00. Thus, the scaling law δ = 1 + γ / β is fulfilled. The critical exponents obey the single scaling equation of M (μ0H, ε) =εβf± (μ0H /ε β + γ) ; where f+ for T > TC and f- for T TC.

  4. Effects of Mn doping on temperature-dependent magnetic properties of L10 FeMnPt

    Science.gov (United States)

    Xu, D. B.; Chen, J. S.; Zhou, T. J.; Chow, G. M.

    2011-04-01

    We report the effect of Mn doping on temperature-dependent magnetic properties of L10 FeMnPt (001) epitaxial films. (001) textured L10 Fe50-xMnxPt50 (x = 0, 5, 10, 15, 20 at. %) films were prepared by cosputtering Fe, Pt, and Mn onto MgO single crystal substrates at 550 °C. θ-2θ XRD scans indicated the lattice parameter c increased whereas the ordering parameter S decreased with Mn doping. The thermal magnetic properties measured using a superconducting quantum interference device showed that Curie temperature TC could be reduced to 500 K with 15 at. % Mn doping, but Ku was decreased to 1.6 × 107 erg/cm3. The relation of temperature-dependent anisotropy and saturation magnetization showed that it did not obey the Callen-Callen theory.

  5. Piezoelectric response of BiFeO3 ceramics at elevated temperatures

    Science.gov (United States)

    Rojac, Tadej; Makarovic, Maja; Walker, Julian; Ursic, Hana; Damjanovic, Dragan; Kos, Tomaz

    2016-07-01

    The high Curie temperature (TC ˜ 825 °C) of BiFeO3 has made this material potentially attractive for the development of high-TC piezoelectric ceramics. Despite significant advances in the search of new BiFeO3-based compositions, the piezoelectric behavior of the parent BiFeO3 at elevated temperatures remains unexplored. We present here a systematic analysis of the converse, longitudinal piezoelectric response of BiFeO3 measured in situ as a function of temperature (25-260 °C), driving-field frequency, and amplitude. Earlier studies performed at room temperature revealed that the frequency and field dependence of the longitudinal response of BiFeO3 is dominated by linear and nonlinear piezoelectric Maxwell-Wagner mechanisms, originating from the presence of local conductive paths along domain walls and grain boundaries within the polycrystalline matrix. This study shows that the same mechanisms are responsible for the distinct temperature dependence of the piezoelectric coefficient and phase angle and thus identifies the local electrical conductivity as the key for controlling the temperature dependent piezoelectric response of BiFeO3 and possibly other, more complex BiFeO3-based compositions.

  6. Topological susceptibility near Tc in SU(3 gauge theory

    Directory of Open Access Journals (Sweden)

    Guang-Yi Xiong

    2016-01-01

    Full Text Available Topological charge susceptibility χt for pure gauge SU(3 theory at finite temperature is studied using anisotropic lattices. The over-improved stout-link smoothing method is utilized to calculate the topological charge. Near the phase transition point we find a rapid declining behavior for χt with values decreasing from (188(1 MeV4 to (67(3 MeV4 as the temperature increased from zero temperature to 1.9Tc which demonstrates the existence of topological excitations far above Tc. The 4th order cumulant c4 of topological charge, as well as the ratio c4/χt is also investigated. Results of c4 show step-like behavior near Tc while the ratio at high temperature agrees with the value as predicted by the diluted instanton gas model.

  7. Identifying the 'inorganic gene' for high-temperature piezoelectric perovskites through statistical learning.

    Science.gov (United States)

    Balachandran, Prasanna V; Broderick, Scott R; Rajan, Krishna

    2011-08-01

    This paper develops a statistical learning approach to identify potentially new high-temperature ferroelectric piezoelectric perovskite compounds. Unlike most computational studies on crystal chemistry, where the starting point is some form of electronic structure calculation, we use a data-driven approach to initiate our search. This is accomplished by identifying patterns of behaviour between discrete scalar descriptors associated with crystal and electronic structure and the reported Curie temperature (TC) of known compounds; extracting design rules that govern critical structure-property relationships; and discovering in a quantitative fashion the exact role of these materials descriptors. Our approach applies linear manifold methods for data dimensionality reduction to discover the dominant descriptors governing structure-property correlations (the 'genes') and Shannon entropy metrics coupled to recursive partitioning methods to quantitatively assess the specific combination of descriptors that govern the link between crystal chemistry and TC (their 'sequencing'). We use this information to develop predictive models that can suggest new structure/chemistries and/or properties. In this manner, BiTmO3-PbTiO3 and BiLuO3-PbTiO3 are predicted to have a TC of 730(°)C and 705(°)C, respectively. A quantitative structure-property relationship model similar to those used in biology and drug discovery not only predicts our new chemistries but also validates published reports.

  8. Exchange coupling and magnetoresistance in CoFe/NiCu/CoFe spin valves near the Curie point of the spacer

    Science.gov (United States)

    Andersson, S.; Korenivski, V.

    2010-05-01

    Thermal control of exchange coupling between two strongly ferromagnetic layers through a weakly ferromagnetic Ni-Cu spacer and the associated magnetoresistance is investigated. The spacer, having a Curie point slightly above room temperature, can be cycled between its paramagnetic and ferromagnetic states by varying the temperature externally or using joule heating. It is shown that the giant magnetoresistance vanishes due to a strong reduction in the mean free path in the spacer at above ˜30% Ni concentration—before the onset of ferromagnetism. Finally, a device is proposed which combines thermally controlled exchange coupling and large magnetoresistance by separating the switching and the readout elements.

  9. Ce-doped LCMO CMR manganites: a consequence of enhanced $T_{c}$ and $T_{\\text{IM}}$

    Indian Academy of Sciences (India)

    D K Mishra; D R Sahu; P K Mishra; S K Singh; B K Mohapatra; B K Roul

    2011-12-01

    A series of Ce-doped (1–20 mol%) La0.67Ca0.33MnO3 (LCMO) sintered (1400°C) ceramic samples were prepared by the solid-state reaction route. The significant enhancement of metal insulator transition temperature ($T_{\\text{IM}} \\approx$ 280 K) and Curie transition temperature ($T_{c} \\approx$ 270 K) associated with LCMO system by the addition of 10 mol% of Ce has been observed. Further interesting observation showed that both low (≈ 1 mol%) and high (≥ 15 and 20 mol%) level of Ce-doping in LCMO reduced the $T_{\\text{IM}}$ appreciably from 280 K to 220 K, and from 100 to 160 K, respectively exhibiting the signature of a unique spin glass transitions at around 30 K. Structural and spectroscopic studies revealed that unreacted CeO2 and MnO2 phases are found to be present in 1, 15, 20 mol% Ce-doped LCMO samples, which is one of the reasons why they show spin glass transition at low temperature. Our present results on bulk Ce-doped (10 mol%) LCMO are found to be encouraging as far as $T_{\\text{IM}}$ of epitaxial La0.7Ce0.3MnO3 thin film ($T_{\\text{IM}} \\approx$ 250 K) is concerned. This finding suggests that single-phase materials of Ce-doped (10 mol%) LCMO can be prepared with enhanced $T_{\\text{IM}}$ effectively using solid-state reaction route.

  10. Ciencia e industria en el desarrollo de la radiactividad: el caso de Marie Curie

    OpenAIRE

    Roqué, Xavier

    1997-01-01

    Not available.Se argumenta que Marie Curie desarrolló sus investigaciones en radiactividad en estrecha relación con la industria de los radioelementos. Esta relación incluyó desde el desarrollo de procedimientos de extracción para diversas sustancias radiactivas, hasta la promoción de su propio laboratorio industrial. La actividad industrial de Curie se aviene mal con su imagen heroica de científica pura, sacrificada y carente de medios, imagen que, paradójicamente, se retrotrae a las campaña...

  11. Presentation of test cases TC-2A, TC-2B, TC-2C, TC-2D - Twodimensional, incompressible, wall flows with separation

    DEFF Research Database (Denmark)

    Scheel Larsen, Poul

    1988-01-01

    The four test cases comprise the backfacing step at high Re-number (TC-2A) and low Re-number (TC-2B), a low Re-number boundary layer flow past a thin obstacle, fence-on-wall (TC-2C), and a high Re-number developed channel flow past a squareobstacle (TC-2D). Geometry, test conditions and available...

  12. A low-temperature study of manganese-induced ferromagnetism and valence band convergence in tin telluride

    Science.gov (United States)

    Chi, Hang; Tan, Gangjian; Kanatzidis, Mercouri G.; Li, Qiang; Uher, Ctirad

    2016-05-01

    SnTe is renowned for its promise in advancing energy-related technologies based on thermoelectricity and for its topological crystalline insulator character. Here, we demonstrate that each Mn atom introduces ˜4 μB (Bohr magneton) of magnetic moment to Sn1-xMnxTe. The Curie temperature TC reaches ˜14 K for x = 0.12, as observed in the field dependent hysteresis of magnetization and the anomalous Hall effect. In accordance with a modified two-band electronic Kane model, the light L-valence-band and the heavy Σ-valence-band gradually converge in energy with increasing Mn concentration, leading to a decreasing ordinary Hall coefficient RH and a favorably enhanced Seebeck coefficient S at the same time. With the thermal conductivity κ lowered chiefly via point defects associated with the incorporation of Mn, the strategy of Mn doping also bodes well for efficient thermoelectric applications at elevated temperatures.

  13. Temperature dependence of magnetic anisotropy constant in iron chalcogenide Fe3Se4: Excellent agreement with theories

    Science.gov (United States)

    Wang, Jun; Duan, Hongyan; Lin, Xiong; Aguilar, Victor; Mosqueda, Aaron; Zhao, Guo-meng

    2012-01-01

    Magnetic hysteresis loops were measured for ferrimagnetic iron chalcogenide Fe3Se4 nanoparticles in the whole temperature range below the Curie temperature TC (315 K). The coercivity of the material is huge, reaching about 40 kOe at 10 K. The magnetic anisotropy constant K was determined from the magnetic hysteresis loop using the law of approach to saturation. The deduced anisotropy constant at 10 K is 5.22×106 erg/cm3, which is over one order of magnitude larger than that of Fe3O4. We also demonstrated that the experimental magnetic hysteresis loop is in good agreement with the theoretical curve calculated by Stoner and Wohlfarth for a noninteracting randomly oriented uniaxial single-domain particle system. Moreover, we show that K is proportional to the cube of the saturation magnetization Ms, which confirms earlier theoretical models for uniaxial magnets. PMID:23258940

  14. Low-temperature specific heat and magnetic properties of the filled skutterudite ferromagnet NdRu4As12

    Science.gov (United States)

    Rudenko, A.; Henkie, Z.; Cichorek, T.

    2016-09-01

    We present the low-temperature specific heat and magnetic properties of the filled skutterudite compound NdRu4As12 that exhibits a ferromagnetic transition at TC ≃ 2.3 K . Magnetic entropy considerations point at a quartet ground state of the Nd3+ ions. Deep in the ferromagnetic state, the heat capacity shows a Schottky anomaly that we ascribe to the Zeeman splitting in the presence of a molecular field. Comparison of the specific heats of NdRu4As12 and its Os-based homologue near their Curie temperatures supports our earlier observation suggesting an unusual lowering of the Th cubic point symmetry in the latter filled skutterudite.

  15. Comparative biological evaluation between {sup 99m}Tc tricarbonyl and {sup 99m}Tc-Sn(II) levosalbutamol as a β{sub 2}-adrenoceptor agonist

    Energy Technology Data Exchange (ETDEWEB)

    Sanad, Mahmoud H. [Atomic Energy Authority, Cairo (Egypt). Labeled Compounds Dept.; Borai, Emad H. [Atomic Energy Authority, Cairo (Egypt). Analytical Chemistry Dept.

    2015-07-01

    This study describes the comparison between {sup 99m}Tc-tricarbonyl and {sup 99m}Tc-Sn (II) levosalbutamol as a β{sub 2}-adrenoceptors radiopharmaceutical and evaluation of their different biological characteristics using experimental animals. Levosalbutamol was labeled firstly with {sup 99m}Tc in the presence of SnCl{sub 2} . 2H{sub 2}O as a reducing agent under the optimum conditions: pH 8, 50 μg SnCl{sub 2} . 2H{sub 2}O, room temperature, 40 μg levosalbutamol and 30 min reaction time to give a maximum radiochemical yield of 98 ± 0.1%. The obtained {sup 99m}Tc-levosalbutamol was stable for a time up to 8 h. Secondly, {sup 99m}Tc-tricarbonyl ([{sup 99m}Tc(CO){sub 3}(H{sub 2}O){sub 3}]{sup +}) levosalbutamol was prepare under 30 min heating at 100 C. Labeling yield and stability were analyzed by high performance liquid chromatography (labeling yield >99% and stability for 8 h). Biodistribution investigation showed that, the maximum uptake ratio of the {sup 99m}Tc-levosalbutamol ({sup 99m}Tc-Lev) between lung and heart was 2.34 ± 0.62 % of the injected activity/g tissue organ, at 30 min post-injection. But in case of {sup 99m}Tc-tricarbonyl levosalbutamol ({sup 99m}Tc-tricarbonyl Lev) the maximum uptake ratio was 3.6 ± 0.11 of the injected activity/g tissue organ, at 30 min post-injection. This indicates that {sup 99m}Tc-tricarbonyl levosalbutamol was more selective for lung β{sub 2}-adrenoceptors than {sup 99m}Tc-levosalbutamol. These results introduce {sup 99m}Tc-tricarbonyl levosalbutamol as a novel potential radiopharmaceutical for lung imaging.

  16. Large magnetic entropy change near room temperature in the LaFe11.5Si1.5H1.3 interstitial compound

    Institute of Scientific and Technical Information of China (English)

    陈远富; 王芳; 沈保根; 胡凤霞; 成昭华; 王光军; 孙继荣

    2002-01-01

    The LaFe11.5Si1.5H1.3 interstitial compound has been prepared. Its Curie temperature TC (288K) has beenadjusted to around room temperature, and the maximal magnetic entropy change (|△S|~17.0J.kg-1.K-1 at TC) islarger than that of Gd (|△S|~ 9.8 J.kg-1.K-1 at TC=293K) by~73.5% under a magnetic change from 0 to ST. Theorigin of the large magnetic entropy change is attributed to the first-order field-induced itinerant-electron metamagnetictransition. Moreover, the magnetic hysteresis of LaFe11.5Si1.5H1.3 under the increase and decrease of the field is verysmall, which is favourable to magnetic refrigeration application. The present study suggests that the LaFe11.5Si1.5H1.3compound is a promising candidate as a room-temperature magnetic refrigerant.

  17. Magnesium potassium phosphate ceramic for {sup 99}Tc immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D. [Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)]. E-mail: dsingh@anl.gov; Mandalika, V.R. [Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Parulekar, S.J. [Department of Chemical and Environmental Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Wagh, A.S. [Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)]. E-mail: wagh@anl.gov

    2006-02-01

    Technetium-99, present in the US Department of Energy's (DOE) high-level waste (HLW) as a by-product of fission reactions, poses a serious environmental threat because it has a long half-life, is highly mobile in its soluble Tc{sup 7+} oxidation state and is volatile at high temperatures. Magnesium potassium phosphate (MKP) ceramics have been developed to treat {sup 99}Tc that has been partitioned and eluted from simulated high-level tank wastes by means of sorption processes. Waste forms were fabricated by adding MKP binder and a reducing agent (SnCl{sub 2}) to the {sup 99}Tc-containing aqueous waste. In addition, waste forms were fabricated by first precipitating {sup 99}Tc from the waste and subsequently solidifying it in MKP. {sup 99}Tc loadings in the waste forms were as high as 900 ppm by weight. Waste form performance was established through various strength, leaching, and durability tests. Long-term leaching studies, as per the ANS 16.1 procedure, showed leachability indices between 11 and 14 for {sup 99}Tc under ambient conditions. The normalized leach rate for {sup 99}Tc, according to the product consistency test, was as low as 1.1 x 10{sup -3} g/m{sup 2} d. The waste forms exhibited a compressive strength of {approx}30 MPa and were durable in an aqueous environment. Containment of {sup 99}Tc in MKP ceramics is believed to be due to a combination of appropriate reducing environment (determined from Eh-pH measurements) and microencapsulation in a dense matrix.

  18. Curie-point pyrolysis of sodium salts of functionalized fatty acids

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hartgers, W.A.; Leeuw, J.W. de

    1995-01-01

    Selected sodium salts of functionalized fatty acids were subjected to Curie-point pyrolysis and their pyrolysis products subsequently analyzed by gas chromatography/mass spectrometry in order to study the thermal dissociation mechanisms of lipid moieties in bio- and geomacromolecules. Pyrolysis of t

  19. Book Review: The Madame Curie Complex: The Hidden History of Women in Science

    DEFF Research Database (Denmark)

    Shield, Andrew DJ

    2012-01-01

    truth about nature. In The Madame Curie Complex: The Hidden History of Women in Science, Julie Des Jardins does not seek to discredit the work of Archimedes; rather, she demonstrates that the image of the superman-scientist saturated the public mindset from the late nineteenth century through the 1960s...

  20. Difficulties in teaching electromagnetism: an eight year experience at Pierre and Marie Curie University

    Directory of Open Access Journals (Sweden)

    H. Roussel

    2012-07-01

    Full Text Available We will begin by outlining the details of how electromagnetics are taught in the  electrical engineering program offered at Pierre and Marie Curie University (a French example from the undergraduate to the Masters degree levels.  We will also discuss how our methods are and should be adapted to teach waves propagation without discouraging students.

  1. The Marie Curie Actions at CERN – reaching out beyond particle physics and Europe

    CERN Multimedia

    EU Projects Office

    2014-01-01

    The European Commission’s Marie Curie Actions have been a pillar of the EU Framework Programmes for several decades as a means of promoting career development and enhancing mobility of researchers in Europe. This corresponds nicely to one of CERN’s main missions: to train the next generation of scientists and engineers.   The European Commissioner for Education, Culture, Multilingualism, Sport, Media and Youth, Androulla Vassiliou (centre) met the Marie Curie Fellows on her visit to CERN in April 2013. CERN has been pleased to be a major player in the Marie Curie Actions under the Sixth and Seventh Framework Programmes (FP6 from 2002 to 2006 and FP7 from 2007 to 2013), being one of the most successful participants in Europe. Under FP7, CERN was ranked first in Switzerland and fifth in Europe against stiff competition in terms of overall funding. Participation was in all of the Marie Curie Actions: Initial Training Networks, Industry-Academia Partnership Pathways, IRSES, CO...

  2. Marie Curie, les femmes et la science, d'hier à aujourd'hui

    CERN Document Server

    CERN. Geneva; Mariotti, Chiara; Vicinanza, Domenico

    2017-01-01

    Marie Curie, les femmes et la science, d'hier à aujourd'hui Conférence par Hélène Langevin-Joliot Avec la participation de l'Echo du Reculet de Thoiry. L'enregistrement et la liste d'attente sont déjà complets... Mais il n'est pas rare que des personnes réservent et ne viennent pas. Nous réassignerons les places libérées selon la règle "premier arrivé, premier inscrit". Au vu de la forte demande, la conférence sera également disponible en vidéoconférence : lien d'accès "webcast" disponible en bas de cette page. Hélène Langevin-Joliot, directrice de recherche émérite en physique nucléaire fondamentale au CNRS à Orsay, est aussi la fille de Frédéric et Irène Joliot-Curie (prix Nobel de chimie en 1935) et la petite-fille de Pierre Curie (prix Nobel de physique en 1903) et de Marie Curie (prix Nobel de physique en 1903 et prix Nobel de chimie en 1911). Hélène Langevin-Joliot nous parlera de sa vie scientifique, de l’histoire extraordinai...

  3. Ciencia e industria en el desarrollo de la radiactividad: el caso de Marie Curie

    Directory of Open Access Journals (Sweden)

    Roqué, Xavier

    1997-01-01

    Full Text Available Not available.Se argumenta que Marie Curie desarrolló sus investigaciones en radiactividad en estrecha relación con la industria de los radioelementos. Esta relación incluyó desde el desarrollo de procedimientos de extracción para diversas sustancias radiactivas, hasta la promoción de su propio laboratorio industrial. La actividad industrial de Curie se aviene mal con su imagen heroica de científica pura, sacrificada y carente de medios, imagen que, paradójicamente, se retrotrae a las campañas de Curie en los años 1920 por dotar a su laboratorio con «medios de acción industriales». Se verá que los valores dominantes del medio científico francés favorecieron la propagación selectiva de la imagen heroica de Curie, que fue luego aceptada acríticamente por la historiografía de la física del siglo XX.

  4. Going to School with Madame Curie and Mr. Einstein: Gender Roles in Children's Science Biographies

    Science.gov (United States)

    Owens, Trevor

    2009-01-01

    One of the first places children encounter science and scientists is children's literature. Children's books about science and scientists have, however, received limited scholarly attention. By exploring the history of children's biographies of Marie Curie and Albert Einstein, the two most written about scientist in children's literature, this…

  5. Living Proof: What Helen Keller, Marilyn Monroe, and Marie Curie Have in Common.

    Science.gov (United States)

    Saul, E. Wendy

    1986-01-01

    Examines biographies of Marie Curie written for children and discusses two types of distortions: simple misrepresentations of fact and selective retelling of the past. It is concluded that biographies of minority or female success should deal specifically with strategies used by the hero or heroine to combat prejudice. (EM)

  6. Marie Curie, les femmes et la science, d'hier à aujourd'hui - English

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Marie Curie, les femmes et la science, d'hier à aujourd'hui Conférence par Hélène Langevin-Joliot Avec la participation de l'Echo du Reculet de Thoiry. L'enregistrement et la liste d'attente sont déjà complets... Mais il n'est pas rare que des personnes réservent et ne viennent pas. Nous réassignerons les places libérées selon la règle "premier arrivé, premier inscrit". Nous envisageons la possibilité de faire un webcast de la conférence. Plus d'information bientôt. Hélène Langevin-Joliot, directrice de recherche émérite en physique nucléaire fondamentale au CNRS à Orsay, est aussi la fille de Frédéric et Irène Joliot-Curie (prix Nobel de chimie en 1935) et la petite-fille de Pierre Curie (prix Nobel de physique en 1903) et de Marie Curie (prix Nobel de physique en 1903 et prix Nobel de chimie en 1911). Hélène Langevin-Joliot nous parlera de sa vie scientifique, de l’histoire extraordinaire de sa famille et en particulier du rôle des ...

  7. Living Proof: What Helen Keller, Marilyn Monroe, and Marie Curie Have in Common.

    Science.gov (United States)

    Saul, E. Wendy

    1986-01-01

    Examines biographies of Marie Curie written for children and discusses two types of distortions: simple misrepresentations of fact and selective retelling of the past. It is concluded that biographies of minority or female success should deal specifically with strategies used by the hero or heroine to combat prejudice. (EM)

  8. Attracting Talented Researchers to Ireland: A review of The European Marie Curie Programme

    OpenAIRE

    Giordani, Silvia

    2007-01-01

    PUBLISHED The purpose of this publication is to illustrate how researchers in academia and industry in Ireland have successfully secured funding from Europe in the Marie Curie Programme and to highlight the impact this has had in furthering their R&D ambitions.

  9. Variational description of Gibbs-non-Gibbs dynamical transitions for the Curie-Weiss model

    NARCIS (Netherlands)

    Fernandez, R.; den Hollander, F.; Martinez, J.

    2013-01-01

    We perform a detailed study of Gibbs-non-Gibbs transitions for the Curie- Weiss model subject to independent spin-flip dynamics (“infinite-temperature” dynamics). We show that, in this setup, the program outlined in van Enter et al. (Moscow Math J 10:687–711, 2010) can be fully completed, namely, Gi

  10. The Marie Curie programme at the Institute of Archaeology 2004-2008

    Directory of Open Access Journals (Sweden)

    Thilo Rehren

    2008-09-01

    Full Text Available The Marie Curie Early Stage Training (MEST projects, run by the European Commission, offer training opportunities to young scientists from EU member states and sometimes also from non-European countries. The Institute of Archaeology hosted one such project between 2004 and 2008, which is described here by its Principal Investigator.

  11. PARTNER: A Marie Curie Initial Training Network for hadron therapy (with english subtitles)

    CERN Multimedia

    CERN BULLETIN; Manuela Cirilli; Nathalie Hospital

    2011-01-01

    PARTNER is a 4-year Marie Curie Training project funded by the European Commission with 5.6 million Euros aimed at the creation of the next generation of experts. Ten academic institutes and research centres and two leading companies are participating in PARTNER, that is coordinated by CERN, forming a unique multidisciplinary and multinational European network.

  12. PARTNER: A Marie Curie Initial Training Network for hadron therapy (with french subtitles)

    CERN Document Server

    CERN BULLETIN; Manuela Cirilli; Nathalie Hospital

    2011-01-01

    PARTNER is a 4-year Marie Curie Training project funded by the European Commission with 5.6 million Euros aimed at the creation of the next generation of experts. Ten academic institutes and research centres and two leading companies are participating in PARTNER, that is coordinated by CERN, forming a unique multidisciplinary and multinational European network.

  13. Getters for Tc and I Removal from Liquid Waste

    Science.gov (United States)

    Qafoku, N. P.; Asmussen, M.; Lawter, A.; Neeway, J.; Smith, G.

    2015-12-01

    A cementitious waste form, Cast Stone, is being evaluated as a possible supplemental waste form for the low activity waste (LAW) at the Hanford Site, which contains significant amounts of radioactive 99Tc and 129I, as part of the tank waste cleanup mission. To improve the retention of Tc and/or I in Cast Stone, materials with a high affinity for Tc and/or I, termed "getters," can be added to decrease the rate of contaminant release and diffusivity, and improve Cast Stone performance. A series of kinetic batch sorption experiments was performed to determine the effectiveness of the getter materials. Several Tc getters [blast furnace slag, Sn (II) apatite, SnCl2, nanoporous Sn phosphate, KMS-2 (a potassium-metal-sulfide), and Sn(II) hydroxyapatite] and I getters [layered Bi hydroxide, natural argentite mineral, synthetic argentite, Ag-impregnated carbon, and Ag-exchanged zeolite] were tested in different solution media, 18.2 MΩ DI H2O and a caustic LAW waste simulant containing 6.5 M Na or 7.8 M Na. The experiments were conducted at room temperature in the presence or absence of air. Results indicated that most Tc getters (with the exception of KMS-2) performed better in the DI H2O solution than in the 6.5 and 7.8 M Na LAW simulant. In addition, Tc sequestration may be affected by the presence of other redox sensitive elements that were present in the LAW simulant, such as Cr. The Tc getter materials have been examined through various solid-state characterization techniques such as XRD, SEM/EDS, XANES and EXAFS which provided evidence for plausible mechanisms of aqueous Tc removal. The results indicated that the Tc precipitates differ depending on the getter material and that Tc(VII) is reduced to Tc(IV) in most of the getters but to a differing extents. For the I getters, Ag-exchanged zeolite and synthetic argentite were the most effective ones. The other I getters showed limited effectiveness for sorbing I under the high ionic strength and caustic conditions of

  14. Raman evidence for presence of high-temperature ferromagnetic clusters in magnetodielectric compound Ba-doped La2NiMnO6

    Science.gov (United States)

    Barbosa, D. A. B.; Paschoal, C. W. A.

    2017-10-01

    Magnetodielectric ferromagnetic semiconductors are key materials because of their applications in spintronic devices; they can be used to control the magnetic properties by applying electric fields. La2NiMnO6 emerged as an important magnetodielectric ferromagnetic semiconductor because of its high Curie temperature near room temperature. Recently Ba doped was successfully used to improve magnetic properties in La2NiMnO6, originating partially ordered systems with different ordering degrees but presenting same Tc = 280 K. However, the influence of Ba doping on the temperature dependent vibrational properties of the system was not investigated. To investigate the Ba doping influence on temperature dependent phonon spectra in La2NiMnO6, we used Raman Spectroscopy to probe the symmetric stretching mode behavior in the range from 10 to 600 K. Remarkable softenings were detected in the phonon behavior due to spin phonon coupling, at several different temperatures, much above Tc. The FWHM dependence with temperature rules out magnetostriction effects. The phonon softenings are the largest reported so far for the RE2NiMnO6 systems and also indicate that Ba doping induces ordering in the Ni/Mn sites. The temperature discordance in characteristic softening onset of the spin phonon coupling are related to ferromagnetic short range clusters due the presence of Ni3 +, Mn3 + oxidation states.

  15. Power Systems Development Facility Gasification Test Run TC07

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2002-04-05

    This report discusses Test Campaign TC07 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC07. Prior to TC07, the Transport Reactor was modified to allow operations as an oxygen-blown gasifier. Test Run TC07 was started on December 11, 2001, and the sand circulation tests (TC07A) were completed on December 14, 2001. The coal-feed tests (TC07B-D) were started on January 17, 2002 and completed on April 5, 2002. Due to operational difficulties with the reactor, the unit was taken offline several times. The reactor temperature was varied between 1,700 and 1,780 F at pressures from 200 to 240 psig. In TC07, 679 hours of solid circulation and 442 hours of coal feed, 398 hours with PRB coal and 44 hours with coal from the Calumet mine, and 33 hours of coke breeze feed were attained. Reactor operations were problematic due to instrumentation problems in the LMZ resulting in much higher than desired operating temperatures in the reactor. Both reactor and PCD operations were stable and the modifications to the lower part of the gasifier performed well while testing the gasifier with PRB coal feed.

  16. Temperature and pressure effects on elastic properties of relaxor ferroelectrics and thermoelectrics: A resonant ultrasound spectroscopy study

    Science.gov (United States)

    Tennakoon, Sumudu P.

    Relaxor ferroelectric lead magnesium niobate-lead titanate (PMN-PT) material exhibits exceptional electromechanical properties. The material undergoes a series of structural phase transitions with changes in temperature and the chemical composition. The work covered in this dissertation seek to gain insight into the phase diagram of PMN-PT using temperature and pressure dependence of the elastic properties. Single crystal PMN-PT with a composition near morphotropic phase boundary (MPB) was investigated using a resonant ultrasound spectroscopy (RUS) methodologies in the temperature range of 293 K - 800 K and the pressure range from near vacuum to 3.4 MPa. At atmospheric pressure, significantly high acoustic attenuation of PMN-PT is observed at temperatures below 400 K. A strong stiffening is observed in the temperature range of 400 K - 673 K, followed by a gradual softening at higher temperatures. With varying pressure, an increased pressure sensitivity of the elastic properties of PMN-PT is observed at the temperatures in the stiffening phase. Elastic behavior at elevated temperatures and pressures were studied for correlations with the ferroelectric domains at temperatures below the Curie temperature (TC), the locally polarized nano-regions, and an existence of pseudo-cubic crystalline at higher temperatures between (TC and TB). Thermoelectric lanthanum tellurides and skutterudites are being investigated by NASA's Jet Propulsion Laboratory for advanced thermoelectric generates (TEGs). Effects of nickel (Ni) doping on elastic properties of lanthanum tellurides at elevated temperatures were investigated in the temperature range of 293 K - 800 K. A linear stiffening was observed with increasing the Ni content in the material. Elastic properties of p-type and n-type bismuth-based skutterudites were investigated in the temperature range of 293 K - 723 K. Elastic properties of rare-earth doped strontium titanate were also investigated in the temperature range of 293 K

  17. Nanoengineering of Flux Pinning Sites in High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Volume pinning forces were determined for a variety of bulk high-Tcsuperconductors of the 123-type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges were identified. The Nd-based superconductors and some YBCO crystalsexhibited a dominating pinning of the δTc-type (i.e., small, superconducting pinning sites). In contrast to this, the addition of insulating 211 particles provided pinning of the δl-type; providing effective pinning in the entire temperature range acting as a "background" pinning mechanism for the peak effect. Due to the small coherence lengths of the high-Tc compounds, effective pinning sites are defects or particles of nanometer size relative to ξ3. Integral magnetic measurements of the magnetization as a function of temperature in large applied magnetic fields (up to 7 T) revealed that practically all high-Tc compounds were spatially inhomogeneous, which could be caused byoxygen deficiency (YBCO), solid solutions of Nd/Ba (NdBCO and other light rare earth compounds), intergrowths (Bi-based superconductors), and doping by pair-breaking dopants like Zn, Pr. This implies that the superconducting sample consists of stronger and weaker superconducting areas, coupled together. In large appliedfields, this coupling gets broken and the magnetization versus temperature curves revealed more than one superconducting transition. In contrast, irradiation experiments by neutrons, protons, and heavy-ions enabled the artificial introduction of very effective pinning sites into the high-Tc superconductors, thus creating a large variety of different observations using magnetic data. From all these observations, we construct a pinning diagram for bulk high-Tc superconductors explaining many features observed in high-Tc samples.

  18. Effect of sintering temperature and composition on microstructure and properties of PMS-PZT ceramics

    Institute of Scientific and Technical Information of China (English)

    DU Hong-liang; PEI Zhi-bin; LI Zhi-min; LUO Fa; ZHU Dong-mei; ZHOU Wan-cheng; QU Shao-bo

    2006-01-01

    The piezoelectric ceramics xPb(Mn1/3Sb2/3)O3-(1-x)Pb(Zr1/2Ti1/2)O3 (abbreviated as PMS-PZT) were synthesized by traditional ceramics process. The effect of sintering temperature and the amount of Pb(Mn1/3Sb2/3)O3 (abbreviated as PMS) on phase structure,microstructure,piezoelectric and dielectric properties of PMS-PZT ceramics was investigated. The results show that the pure perovskite phase is in all ceramics specimens,the phase structure of PMS-PZT ceramics changes from tetragonal phase to single rhombohedral phase with the increasing amount of PMS. The dielectric constant -r,Curie temperature TC,electromechanical coupling factor kp and piezoelectric constant d33 decrease,whereas the mechanical quality factor Qm and dielectric loss tanδ increase with the increasing amount of PMS in system. The optimum sintering temperature is 1 200-1 250 ℃. It is concluded that the PMS-PZT (x=0.07) ceramics sintered at 1 250 ℃ is suitable for high-power piezoelectric transformer. These properties include -r=674.8,tanδ=0.005 25,kp=0.658,Qm1520,d33=230 pC/N,Tc=275 ℃.

  19. Giant volume magnetostriction and colossal magnetoresistance at room temperature in La(0.7)Ba(0.3)MnO(3).

    Science.gov (United States)

    Demin, R V; Koroleva, L I; Mukovskii, Ya M

    2005-01-12

    Giant volume magnetostriction at room temperature is found for the first time in a La(0.7)Ba(0.3)MnO(3) single crystal, achieving 2.54 × 10(-4) in a magnetic field of 8.2 kOe. An even greater value of the volume magnetostriction, equal to 4 × 10(-4) in the same magnetic field, is observed at the Curie point T(C) = 310 K.Volume magnetostriction and magnetoresistance exhibit similar dependences on temperature and magnetic field in the T(C)-region, that is explained by the presence in this compound of a magnetic two-phase ferromagnetic-antiferromagnetic state due to strong s-d exchange.

  20. Temperature and frequency characteristics of low-loss MnZn ferrite in a wide temperature range

    Science.gov (United States)

    Sun, Ke; Lan, Zhongwen; Yu, Zhong; Xu, Zhiyong; Jiang, Xiaona; Wang, Zihui; Liu, Zhi; Luo, Ming

    2011-05-01

    A low-loss Mn0.7Zn0.24Fe2.06O4 ferrite has been prepared by a solid-state reaction method. The MnZn ferrite has a high initial permeability, μi (3097), a high saturation induction, Bs (526 mT), a high Curie temperature, Tc (220 °C), and a low core loss, PL (≤ 415 kW/m3) in a wide temperature (25-120 °C) and frequency (10-100 kHz) range. As the temperature increases, an initial decrease followed by a subsequent increase of hysteresis loss, Ph, and eddy current loss, Pe is observed. Both Ph and Pe increase with increasing frequency. When f ≥ 300 kHz, a residual loss, Pr, appears. Pe increases with increasing temperature and frequency. The temperature and frequency dependence of Ph can be explained by irreversible domain wall movements, Pe by the skin effect, and Pr by domain wall resonance, respectively.

  1. Rugged Low-Resistance Contacts To High-Tc Superconductors

    Science.gov (United States)

    Caton, Randall; Selim, Raouf; Byvik, Charles E.; Buoncristiani, A. Martin

    1992-01-01

    Newly developed technique involving use of gold makes possible to fabricate low-resistance contacts with rugged connections to high-Tc superconductors. Gold diffused into specimen of superconducting material by melting gold beads onto surface of specimen, making strong mechanical contacts. Shear strength of gold bead contacts greater than epoxy or silver paste. Practical use in high-current-carrying applications of new high-Tc materials, including superconducting magnets, long-wavelength sensors, electrical ground planes at low temperatures, and efficient transmission of power.

  2. Enhanced High Temperature Piezoelectrics Based on BiScO3-PbTiO3 Ceramics

    Science.gov (United States)

    Sehirlioglu, Alp; Sayir, Ali; Dynys, Fred

    2009-01-01

    High-temperature piezoelectrics are a key technology for aeronautics and aerospace applications such as fuel modulation to increase the engine efficiency and decrease emissions. The principal challenge for the insertion of piezoelectric materials is the limitation on upper use temperature which is due to low Curie-Temperature (TC) and increasing electrical conductivity. BiScO3-PbTiO3 (BS-PT) system is a promising candidate for improving the operating temperature for piezoelectric actuators due to its high TC (greater than 400 C). Bi2O3 was shown to be a good sintering aid for liquid phase sintering resulting in reduced grain size and increased resistivity. Zr doped and liquid phase sintered BS-PT ceramics exhibited saturated and square hysteresis loops with enhanced remenant polarization (37 microC per square centimeter) and coercive field (14 kV/cm). BS-PT doped with Mn showed enhanced field induced strain (0.27% at 50kV/cm). All the numbers indicated in parenthesis were collected at 100 C.

  3. Curie's hypotheses concerning radioactivity and the origin of the elements

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, P.K.

    1999-09-01

    Pierre Curie gave two hypotheses at first; (1) It can be supposed that the radioactive substances borrow the energy, which they release, from an external radiation, and their radiation would then be a secondary radiation, (2) It can be supposed that the radioactive substances draw from themselves the energy which they release. The second hypothesis has shown the more fertile in explaining the properties of the radioactive substances. Consequently, the first hypothesis became more or less forgotten. It appears, however, the first hypothesis should play an important role in explaining the phenomena concerning the origin of the elements. The Oklo Phenomenon has demonstrated that a nuclear fire had once existed on our planet earth and formation of heavy elements was occurring in nature. The author pointed out that the difference in the isotopic compositions of xenon found in meteorites, lunar samples and in the earth's atmosphere can only be explained as due to the alterations of the isotropic compositions of xenon by combined effect of (a) mass-fractionation, (b) spallation, and (c) stellar temperature neutron-capture reactions. The strange xenon components are not isotopically pure substance. Instead, xenon-HL is a mixture of the {sup 244}Pu fission xenon and the xenon whose isotopic compositions is severely altered by a combined effect of the processes (a), (b) and (c) mentioned above. These results also indicate that C1 carbonaceous chondrites, which is generally as the most primitive sample of the solar system material, began to retain its xenon 5.1 billion years ago, when the plutonium to uranium ratio in the solar system was as high as almost 0.6 (atom/atom), while the C2 carbonaceous chondrite began to retain their xenon about 150 million years later and the ordinary chondrites and achondrite about 500 to 600 million years later. This means that the birth of the solar system began soon after the last supernova exploded about 5.1 billion years ago, and the

  4. The Distribution of Tc in Purex

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tc is an important fission product (fission yield of 99Tc is 6.13%) and has complex chemical behavior. It distributes in many flows of Purex. The influence of Tc can be ignored in military plutonium production reactor because the burning up of it is very low and the production of Tc is little. The burning up of PWR is much deeper and the production of Tc is much higher than the former so the tendency and controlling of Tc in Purex causes popular consideration. The main reason for that is the peculiar chemical property of Tc. Tc co-extracts with Zr, U and Pu in 1A cell and effect the separation of U or Pu in 1B cell by consuming large amount of reductants and

  5. [Marie Curie, née Maria Sklodowska (1867-1934)--contribution to the development of radiology].

    Science.gov (United States)

    Babić, Rade R; Babić, Gordana Stanković

    2011-01-01

    Marie Curie, née Maria Sklodowska, was born on November 7, 1867 in Warsaw (Poland). She suffered from leukaemia and died on June 4, 1934. She was buried with full honours at Pantheon. Marie Curie and her husband Pierre Curie discovered the radioactive elements Polonium (84Po210), Thorium (90Th232) and Radium (88Ra226). Marie Curie introduced the term radioactivity into science. She was the first woman who got Ph.D. in France, the first woman professor at Sorbonne, Paris and Medical Academy. Of all the women who have ever won the Nobel Prize, Marie Curie was the only who received it twice. During World War I Marie Curie designed a mobile x-ray room "radiologic car". Marie Curie had an x-ray machine installed into a car and demonstrated how to use its dynamo for electric power production necessary for the x-ray machine to work. She had 20 cars with moving radiological lab made and trained 150 people to work on them. She brought something radically new into military medicine--mobile x-ray diagnostics. With the discovery of radioactive elements a new medical branch, radiotherapy, was developed.

  6. NMR/MRI with hyperpolarized gas and high Tc SQUID

    Science.gov (United States)

    Schlenga, Klaus; de Souza, Ricardo E.; Wong-Foy, Annjoe; Clarke, John; Pines, Alexander

    2000-01-01

    A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.

  7. Superconducting bolometers: high-Tc and low-Tc

    Science.gov (United States)

    Richards, Paul L.

    1991-07-01

    A description is given of recent work at Berkeley on superconducting detectors and mixers for infrared and millimeter wavelengths. The first report is a review article which summarizes the status of development of superconducting components for infrared and millimeter wave receivers. Next, a report is given on measurements and theoretical modeling of the absorptivity (surface resistance) of high quality epitaxial films of the high-Tc superconductor YBCO from 750 GHz to 21 THz. The next report describes measurements of the thermal boundary resistance between YBCO films and various substrates. This resistance is much larger than expected from the acoustic impedance mismatch model and gives a thermal time constant in the nanosecond range for typical YBCO films. Reports are also included on the design and experimental performance of two different types of high-Tc bolometric detectors. One is a conventional bolometer with a gold-black absorber. The other is an antenna coupled microbolometer. The properties of a low-Tc microbolometer are also described. The last reports describe accurate measurements and also theoretical modeling of an SIS quasi-particle waveguide mixer for W-band which uses very high quality Ta junctions. The best mixer noise is only 1.3 times the quantum limit. Both the mixer gain and the noise are in quantitative agreement with the quantum theory.

  8. Magnetic materials at finite temperatures: thermodynamics and combined spin and molecular dynamics derived from first principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Eisenbach, Markus [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perera, Meewanage Dilina N. [Univ. of Georgia, Athens, GA (United States). Center for Simulational Physics; Landau, David P [Univ. of Georgia, Athens, GA (United States). Center for Simulational Physics; Nicholson, Don M. [Univ. of North Carolina, Asheville, NC (United States). Dept. of Physics; Yin, Junqi [Univ. of Tennessee, Knoxville, TN (United States). National Inst. for Computational Sciences; Brown, Greg [Florida State Univ., Tallahassee, FL (United States). Dept. of Physics

    2015-01-01

    We present a unified approach to describe the combined behavior of the atomic and magnetic degrees of freedom in magnetic materials. Using Monte Carlo simulations directly combined with first principles the Curie temperature can be obtained ab initio in good agreement with experimental values. The large scale constrained first principles calculations have been used to construct effective potentials for both the atomic and magnetic degrees of freedom that allow the unified study of influence of phonon-magnon coupling on the thermodynamics and dynamics of magnetic systems. The MC calculations predict the specific heat of iron in near perfect agreement with experimental results from 300K to above Tc and allow the identification of the importance of the magnon-phonon interaction at the phase-transition. Further Molecular Dynamics and Spin Dynamics calculations elucidate the dynamics of this coupling and open the potential for quantitative and predictive descriptions of dynamic structure factors in magnetic materials using first principles-derived simulations.

  9. Radioisótopos e sociedade : o legado de Marie Curie 100 anos depois

    OpenAIRE

    André, João P.; Sá, Arsénio Vasconcelos

    2011-01-01

    No ano em que se comemora o centenário da atribuição do Prémio Nobel da Química a Marie Curie e o Ano Internacional da Química, é oportuno recordar e analisar a herança deixada à Humanidade por esta cientista excepcional. Trata-se de um legado que não só revolucionou a ciência como igualmente teve impactos profundos e incontornáveis na sociedade. A aplicação clínica dos radioisótopos, por ela e por Pierre Curie preconizada, constitui uma das armas mais poderosas para o combate ao cancro actua...

  10. Radioisótopos e sociedade : o legado de Marie Curie 100 anos depois

    OpenAIRE

    André, João P.; Sá, Arsénio Vasconcelos

    2011-01-01

    No ano em que se comemora o centenário da atribuição do Prémio Nobel da Química a Marie Curie e o Ano Internacional da Química, é oportuno recordar e analisar a herança deixada à Humanidade por esta cientista excepcional. Trata-se de um legado que não só revolucionou a ciência como igualmente teve impactos profundos e incontornáveis na sociedade. A aplicação clínica dos radioisótopos, por ela e por Pierre Curie preconizada, constitui uma das armas mais poderosas para o combate ao cancro actua...

  11. The research school of Marie Curie in the Paris faculty, 1907-14.

    Science.gov (United States)

    Davis, J L

    1995-07-01

    As the most famous woman scientist of the twentieth century, there has been no shortage of books and articles on the life and career of Marie Curie (1867-1934). Her role as director of a laboratory-based research school in the new scientific field of radioactivity, a field which embraced both chemistry and physics, however, has never been examined. In recent years, there has been a growing interest in the question of research schools, and Morrell, Ravetz, Geison, and Klosterman, amongst others, have written on this subject. Using, in part, the methodology of Morrell, this paper investigates the role of Marie Curie as a school director in the Paris Faculty in the years 1907-14, examining the work and characteristics of her school and assessing her effectiveness as a director.

  12. Nanoporous magnets of chiral and racemic [{Mn(HL)}2Mn{Mo(CN)7}2] with switchable ordering temperatures (TC = 85 K 106 K) driven by H2O sorption (L = N,N-dimethylalaninol).

    Science.gov (United States)

    Milon, Julie; Daniel, Marie-Christine; Kaiba, Abdellah; Guionneau, Philippe; Brandès, Stéphane; Sutter, Jean-Pascal

    2007-11-14

    Molecule-based solids represent a rare opportunity to combine, adjust, and interrelate structural and physical functionalities to develop multifunctional materials. Here we report on a series of porous supramolecular magnets whose magnetic properties are related to their sorption state. A family of magnets of the formula [{Mn(HL)(H2O)}2Mn{Mo(CN)7}2].2H2O have been obtained by assembling the heptacyano-metalate building unit {Mo(CN)7}4- with Mn(II) in the presence of protonated N,N-dimethylalaninol (L) as ligand, the latter being either as a racemic mixture or as a chiral R- or S-enantiomer. The resulting magnets possess an open framework structure and exhibit a TC with a switching behavior (TC = 85 K 106 K) as a function of the hydration state. Moreover, chiral magnets are formed with the optically active ligands. The H2O and gas (N2, CO2, CO) sorption features, the magnetic behavior of both the hydrated and dehydrated magnets, and the crystal structures of the hydrated chiral (S) and racemic magnets are described.

  13. MARIE CURIE

    Directory of Open Access Journals (Sweden)

    EDGAR SERNA MONTOYA

    2011-12-01

    Full Text Available María Sklodowska ‒Marie Curie‒ fue pionera en la ciencia de la radiactividad; es mejor conocida como la descubridora de los elementos radiactivos polonio y radio, y como el primer científico en ganar dos premios Nobel: Física y Química. Para sus colegas y el público en general, el radio fue la clave para un cambio fundamental en nuestra comprensión de la materia y la energía. Su trabajo no sólo influyó en el desarrollo de la ciencia fundamental, sino que también marcó el comienzo de una nueva era en la investigación y los tratamientos médicos.

  14. Curie temp erature mechanism in La(Fe,Si)13 comp ound%La(Fe,Si)13化合物的居里温度机制

    Institute of Scientific and Technical Information of China (English)

    王芳; 汪金芝; 冯唐福; 孙仁兵; 余盛

    2014-01-01

    NaZn13型La(Fe,Si)13化合物随Si含量增加,相变性质由一级过渡为二级,化合物晶胞体积收缩,饱和磁化强度降低,居里温度升高。其居里温度与晶胞体积之间的关系不能用Bethe-Slater曲线给出合理的解释。本文利用添加间隙原子碳调节La(Fe,Si)13化合物晶胞体积和居里温度的方法,系统研究了该化合物居里温度与晶胞体积之间的关系。结果发现二者之间的变化规律遵循Jaccarino-Walker模型,即仅有5%甚至更少的3d电子被认为是真正的巡游电子,其余的3d电子仍是局域的。以极化的巡游电子为媒介,局域电子之间产生类似于Ruderman-Kittel-Kasuya-Yosida 的长程相互作用,相互作用的符号和大小与距离呈周期性震荡。随Si含量的增加, La(Fe,Si)13化合物巡游电子数目增加,化合物的居里温度由晶胞体积和巡游电子的浓度共同决定。%In NaZn13 type La(Fe,Si)13 compound, the phase transition nature varies from the first order to the second order, the cell volume contracts, the saturated magnetization decreases and the Curie temperature increases with increasing Si content. In this paper, the relation between the Curie temperature and the cell volume is investigated systematically by introducing the interstitial carbon atoms, which is an efficient method to control the cell volume and the Curie temperature. It is found that the relation between the Curie temperature and the cell volume is consistent with the Jaccarino-Walker model, in which only 5% or less 3d electrons are considered as the itinerant electrons and the others are regarded as the localized ones. With the polarized itinerant electrons used as a medium, the interaction between the 3d localized electrons is similar to Ruderman-Kittel-Kasuya-Yosida interaction, whose sign and magnitude oscillate periodically with distance. The number of the itinerant electrons of the La (Fe,Si)13 increases with the increase of Si content. The Curie

  15. A giant magnetocaloric effect with a tunable temperature transition close to room temperature in Na-deficient La0.8Na0.2-x□xMnO3 manganites.

    Science.gov (United States)

    Wali, M; Skini, R; Khlifi, M; Dhahri, E; Hlil, E K

    2015-07-28

    A giant magnetocaloric effect induced by sodium-deficiency in a La0.8Na0.2-x□xMnO3 (0.00 ≤ x ≤ 0.15) polycrystalline sample is reported in the present research work. The ability to tune the temperature transition close to room temperature is revealed to be possible by changing the sodium-deficiency content as well. All samples were synthesized using solid-solid reaction. X-ray diffraction and magnetization measurements were performed to investigate their crystallographic structure and magnetocaloric properties. A rhombohedral structure with the R3[combining macron]c space group is deduced from pattern diffraction refinement of all samples. A second-order magnetic phase transition from the ferromagnetic to the paramagnetic state at the Curie temperature (Tc) is observed. Such a Tc decreased from 335 to 260 K when the sodium deficiency rate increased. Besides, the magnetic entropy change and the related Relative Cooling Power (RCP) values, sensitive to sodium-deficiency, were estimated. The magnetic entropy change ranges increased from 2.38 J kg(-1) K(-1) to 3.48 J kg(-1) K(-1) under a magnetic field of 2 T, whereas the RCP varied from 210 to 235 J kg(-1) under an applied magnetic field of 5 T, when x increased from 0.00 to 0.15. The comparison of the values reported in the reference Gd material underlines that the proposed oxide material has substantial advantages for magnetic refrigeration.

  16. A new approach for manufacturing and processing targets to produce 99mTc with cyclotrons

    Science.gov (United States)

    Matei, L.; McRae, G.; Galea, R.; Niculae, D.; Craciun, L.; Leonte, R.; Surette, G.; Langille, S.; Louis, C. St.; Gelbart, W.; Abeysekera, B.; Johnson, R. R.

    2017-06-01

    The most important radioisotope for nuclear medicine is 99mTc. After the supply crisis of 99Mo starting in 2008, the availability of 99mTc became a worldwide concern. Alternative methods for producing the medical imaging isotope 99mTc are actively being developed around the world. The reaction 100Mo(p, 2n)99mTc provides a direct route that can be incorporated into routine production in nuclear medicine centers that possess medical cyclotrons for production of other isotopes, such as those used for Positron Emission Tomography. This paper describes a new approach for manufacturing targets for the (p, 2n) nuclear reaction on 100Mo and the foundation for the subsequent commercial separation and purification of the 99mTc produced. Two designs of targets are presented. The targets used to produce 99mTc are subject to a number of operational constraints.They must withstand the temperatures generated by the irradiation, accommodate temperature gradients from cooling system of the target, must be resilient and must be easily post-processed to separate the 99mTc. After irradiation, the separation of Tc from Mo was carried out using an innovative two-step approach. The process described in this paper can be automated with modules that easily fit in standard production hot cells found in nuclear medicine facilities.

  17. Progress and prospect on the research of new iron-based high-Tc superconductors

    Institute of Scientific and Technical Information of China (English)

    Xian-hui CHEN

    2010-01-01

    @@ Since the discovery of high-Tc copper oxides, researches on high-Tc superconductors and their physical mechanism have become one of the hottest topics in condensed matter physics. In conventional superconductors, superconductivity occurs at very low temperatures. When superconductive, a material presents zero resistance and diamagnetism which is called Meissner Effect. The highTc superconductors are the materials whose superconducting transition temperatures are beyond the McMillan limit of 39 K. However, up to now, the mechanism of the copper oxide superconductors is still under debate.

  18. The doping dependence of T* - what is the real high-Tc phase diagram?

    OpenAIRE

    2000-01-01

    Underdoped high-Tc superconductors are frequently characterised by a temperature, T*, below which the normal-state pseudogap opens. Two different "phase diagrams" based on the doping (p) dependence of T* are currently considered: one where T* falls to zero at a critical doping state and the other where T* merges with Tc in the overdoped region. By examining the temperature dependence of the NMR Knight shift and relaxation rate, entropy, resistivity, infrared conductivity, Raman scattering, AR...

  19. Magnetic properties and temperature-dependent half-metallicity of Co2Mn(Ga(1-x)Z(x)) (Z=Si, Ge, Sn) from first-principles calculation.

    Science.gov (United States)

    Luo, Hu-Bin; Hu, Qing-Miao; Li, Chun-Mei; Johansson, Börje; Vitos, Levente; Yang, Rui

    2013-04-17

    Using the first-principles exact muffin-tin orbitals method in combination with the coherent potential approximation, we investigated the magnetic properties, exchange interactions, and temperature-dependent half-metallicity of the Co2Mn(Ga1-xZx) (Z=Si, Ge, Sn) alloys. The total magnetic moment follows perfectly a previously proposed Slater-Pauling relation, i.e., μ0 = Nt - 24, with Nt being the number of valence electrons. The Co-Mn and Co1-Co2 (inter-sublattice) interactions are dominated by direct exchange, whereas the Co1-Co1 (intra-sublattice) interaction is characterized by superexchange. The Mn-Mn exchange interaction in Co2MnGa is of long-ranged RKKY-type. However, the Mn-Mn exchange interactions in Co2MnZ are relatively localized and can be attributed to superexchange. The Co-Mn, Co1-Co2 and Co1-Co1 total exchange interactions increase with x, whereas the Mn-Mn total exchange interactions show convex behavior. The calculated Curie temperature (TC) increases with x. The ability of Z to enhance TC follows the sequence of Si > Ge > Sn, in agreement with the experimental findings. The temperature dependence of the spin polarization at the Fermi level [P(T)] is investigated based on the disordered local moment model. P(T) drops abruptly at temperatures much lower than TC. At temperatures higher than 200 K, the composition with higher TC generally corresponds to larger P(T).

  20. Unconventional high-Tc superconductivity in fullerides.

    Science.gov (United States)

    Takabayashi, Yasuhiro; Prassides, Kosmas

    2016-09-13

    A3C60 molecular superconductors share a common electronic phase diagram with unconventional high-temperature superconductors such as the cuprates: superconductivity emerges from an antiferromagnetic strongly correlated Mott-insulating state upon tuning a parameter such as pressure (bandwidth control) accompanied by a dome-shaped dependence of the critical temperature, Tc However, unlike atom-based superconductors, the parent state from which superconductivity emerges solely by changing an electronic parameter-the overlap between the outer wave functions of the constituent molecules-is controlled by the C60 (3-) molecular electronic structure via the on-molecule Jahn-Teller effect influence of molecular geometry and spin state. Destruction of the parent Mott-Jahn-Teller state through chemical or physical pressurization yields an unconventional Jahn-Teller metal, where quasi-localized and itinerant electron behaviours coexist. Localized features gradually disappear with lattice contraction and conventional Fermi liquid behaviour is recovered. The nature of the underlying (correlated versus weak-coupling Bardeen-Cooper-Schrieffer theory) s-wave superconducting states mirrors the unconventional/conventional metal dichotomy: the highest superconducting critical temperature occurs at the crossover between Jahn-Teller and Fermi liquid metal when the Jahn-Teller distortion melts.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'.

  1. 载人航天用TC-5A和TC-13X分子筛的研制及评价%Development and Evaluation of TC-5A and TC-13X Molecular Sieve in Manned Spacecraft

    Institute of Scientific and Technical Information of China (English)

    胡宏杰; 冯安生; 韩永强; 董文平; 刘宏召; 金梅; 张秀峰; 郭庆宏

    2013-01-01

    Objective To develop molecular sieves for manned spacecraft and evaluate their effectiveness.Methods Shaping,drying,baking,recrystalization,re-exchange and re-baking were adopted in the development of the molecular sieves.The static and dynamic behavior were tested by isothermal adsorption and by four-bed molecular sieves system.Results The TC-5A CO2 adsorption capacity was 19.7% and TC-13X moisture capacity was 29.15%.The kinetic experiments in four-bed molecular sieve system (4BMS) showed that the dew point at the outlet of drying bed was kept below-40 ℃ and the CO2 removal capacity was 2.17 ~6.17 kg/d when the regeneration temperatures of adsorption bed and drying bed were 280 ℃ and 120 ℃ respectively.Conclusion TC-5A and TC-13X can be used in 4BMS to remove CO2 effectively in a space capsule with three crew members.%目的 研制载人航天专用分子筛,并进行应用效果评价.方法 分子筛产品的研制采用造粒、烘干、焙烧、二次晶化、二次交换和二次焙烧技术,并通过等温吸附和4床分子筛试验进行静态动态性能评价.结果 研制的TC-5A和TC-13X分子筛产品,CO2和H2O的静态吸附能力分别达到19.7%和29.15%,在4床分子筛动态试验中,吸附床再生温度280℃,干燥床达120℃,干燥床出口空气露点小于-40℃,吸附床CO2动态处理能力为2.17 ~6.17 kg/d.结论 TC-5A和TC-13X分子筛应用于4床分子筛CO2处理系统,能够保证系统稳定运转,CO2处理量可满足3人密闭生存空间对CO2浓度控制的需要.

  2. Tc-99 Adsorption on Selected Activated Carbons - Batch Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Wellman, Dawn M.; Golovich, Elizabeth C.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    conducted to ascertain the effects of changing pH showed that at pH values of 6.5 and 7.5, no significant differences existed in Tc-adsorption performance for three of the carbons, but the fourth carbon performed better at pH 7.5. When the pH was increased to 8.5, a slight decline in performance was observed for all carbons. Tests conducted to ascertain the temperature effect on Tc-99 adsorption indicated that at 21 ºC, 27 ºC, and 32 ºC there were no significant differences in Tc-99 adsorption for three of the carbons. The fourth carbon showed a noticeable decline in Tc-99 adsorption performance with increasing temperature. The presence of volatile organic compounds (VOCs) in the source water did not significantly affect Tc-99 adsorption on either of two carbons tested. Technetium-99 adsorption differed by less than 15% with or without VOCs present in the test water, indicating that Tc-99 adsorption would not be significantly affected if VOCs were removed from the water prior to contact with carbon.

  3. O legado de Madame Curie : uma abordagem CTS para o ensino da radioatividade

    OpenAIRE

    Jucelino Cortez

    2014-01-01

    Nesta dissertação relatamos uma experiência de ensino de Radioatividade motivada na abordagem Ciência, Tecnologia e Sociedade (CTS) e trabalhada com os estudantes do terceiro ano da Escola Estadual de Ensino Médio Ponche Verde, em Sertão, Rio Grande do Sul, em 2013. A vida e o legado de Marie Curie foram usados como mote central para uma introdução multidisciplinar ao conteúdo de Radioatividade, que envolveu Biologia, História, Química, Filosofia, Sociologia, Matemática, Medicina, além de Fís...

  4. Experimental studies on imaging of infected site with 99mTc-Iabeled ciprofloxacin in mice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; JIANG Ning-yi; ZHU Lin

    2009-01-01

    Background Bacterial infection can pose a substantial diagnostic dilemma.99mTc-labeled ciprofloxacin (CPF) was developed as a biologically active radiopharmaceutical to diagnose infection.In the present research,we studied the biodistribution and imaging properties of infection tracer 99mTc-CPF in a mouse model of infection.Methods CPF was labeled with 99mTc and the radiochemical purity and labeling rate were measured.A mouse model of infection was established.We then determined the biodistribution of 99mTC-CPF and conducted the whole body scintigraphy of the animal model.Results 99mTc-Ciprotech was stable for at least 6 hours at room temperature.The labeling rate of CPF by 99mTc was over 90%.Clearance of radioactivity mainly occurred in the liver and kidney,and the clearance from blood was rapid.Both biodistribution and imaging results showed higher uptake of 99mTc-CPF at sites of infection.The infectious tissue/normal tissue ratio peak was 4.30 at 4 hours after injection.Conclusions 99mTc-CPF is a sensitive radiopharmaceutical for scintigraphy of infectious lesions and it is easy to prepare.

  5. Power Systems Development Facility Gasification Test Run TC09

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2002-09-30

    This report discusses Test Campaign TC09 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier during TC09 in air- and oxygen-blown modes. Test Run TC09 was started on September 3, 2002, and completed on September 26, 2002. Both gasifier and PCD operations were stable during the test run, with a stable baseline pressure drop. The oxygen feed supply system worked well and the transition from air to oxygen was smooth. The gasifier temperature varied between 1,725 and 1,825 F at pressures from 125 to 270 psig. The gasifier operates at lower pressure during oxygen-blown mode due to the supply pressure of the oxygen system. In TC09, 414 hours of solid circulation and over 300 hours of coal feed were attained with almost 80 hours of pure oxygen feed.

  6. Producing Ceramic High Tc Superconductors for Strong Current Applications

    Institute of Scientific and Technical Information of China (English)

    Jian-Xun Jin; Yuan-Chang Guo; Xue-Kei Fu; Shi-Xue Dou

    2000-01-01

    @@ Strong current and large-scale application is the most important prospect of high Tc superconductors (HTS).Practical HTS samples, both in forms of wire and bulk, have been produced with high critical currents operated at economic cryogenic temperatures, and studied for engineering applications with various prototype devices. The applicable HTS materials produced are introduced in this paper with regard to processing, characterization and application.

  7. 双层CuO2铜酸盐高温超导体的临界温度与电负性标度%Electronegativity and Tc in High-Temperature Superconduct ors of Cuprate HTSC with Two Layers of CuO2

    Institute of Scientific and Technical Information of China (English)

    洪全

    2001-01-01

    The diffence between the geometri averages of ne gative of energy of valence orbit for cations and anions in suggested conducting -resonance-elements of some cuprate high-temperature superconductors with two layers of CuO2 are evaluated.The relationship between ΔX0 and crisis t hemperature Tc was found to fit line.%一些有代表性的双层CuO2铜酸盐高温超导体中假 设的导电共振单元的阴离子和阳离子的价层轨道能负值的几何平均值的差(ΔX0 )与临界温度Tc存在线性关系.

  8. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

    The present book aims at describing the phenomenon of superconductivity and high-temperature superconductors discovered by Bednorz and Muller in 1986. The book covers the superconductivity phenomenon, structure of high-Tc superconductors, critical currents, synthesis routes for high Tc materials, superconductivity in cuprates, the proximity effect and SQUIDs, theories of superconductivity and applications of superconductors.

  9. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

    2010-08-01

    Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

  10. Magnetic Signatures and Curie Surface Trend Across an Arc-Continent Collision Zone: An Example from Central Philippines

    Science.gov (United States)

    Manalo, Pearlyn C.; Dimalanta, Carla B.; Ramos, Noelynna T.; Faustino-Eslava, Decibel V.; Queaño, Karlo L.; Yumul, Graciano P.

    2016-05-01

    Ground and aeromagnetic data are combined to characterize the onshore and offshore magnetic properties of the central Philippines, whose tectonic setting is complicated by opposing subduction zones, large-scale strike-slip faulting and arc-continent collision. The striking difference between the magnetic signatures of the islands with established continental affinity and those of the islands belonging to the island arc terrane is observed. Negative magnetic anomalies are registered over the continental terrane, while positive magnetic anomalies are observed over the Philippine Mobile Belt. Several linear features in the magnetic anomaly map coincide with the trace of the Philippine Fault and its splays. Power spectral analysis of the magnetic data reveals that the Curie depth across the central Philippines varies. The deepest point of the magnetic crust is beneath Mindoro Island at 32 km. The Curie surface shallows toward the east: the Curie surface is 21 km deep between the islands of Sibuyan and Masbate, and 18 km deep at the junction of Buruanga Peninsula and Panay Island. The shallowest Curie surface (18 km) coincides with the boundary of the arc-continent collision, signifying the obduction of mantle rocks over the continental basement. Comparison of the calculated Curie depth with recent crustal thickness models reveals the same eastwards thinning trend and range of depths. The coincidence of the magnetic boundary and the density boundary may support the existence of a compositional boundary that reflects the crust-mantle interface.

  11. TC-1 Satellite of DSP Delivered

    Institute of Scientific and Technical Information of China (English)

    SunQing

    2004-01-01

    TC-1 satellite of Double Star Program (DSP), a near-earth equatorial satellite, was delivered to the representative of the end user, the Research Center for Space Science and Application under the Chinese Academy of Sciences (CAS) on April 12, 2004, which symbolized that TC-1 satellite was put into operation formally.

  12. Scintillating 99Tc Selective Ion Exchange Resins

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell Greenhalgh; Richard D. Tillotson

    2012-07-01

    Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

  13. A novel magnetic valve using room temperature magnetocaloric materials

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian; Pryds, Nini;

    2012-01-01

    Magnetocaloric materials with near-room-temperature tuneable Curie temperatures have been utilized to develop a novel magnetic valve technology. The temperature dependent attractive force between the materials and a permanent magnet assembly is used to actuate valves as a response to temperature...... changes. This is made possible by the strong temperature dependence of the magnetization close to the Curie temperature of the magnetocaloric materials. Different compositions of both La0.67(Ca,Sr)0.33MnO3 and La(Fe,Co,Si)13 have been considered for use in prototype valves. Based on measured magnetization...

  14. Spin polarization effect for Tc2 molecule

    Institute of Scientific and Technical Information of China (English)

    Yan Shi-Ying; Zhu Zheng-He

    2004-01-01

    Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc2 molecule. The result shows that the ground state for Tc2 molecule is an 11-multiple state and its electronic configuration is 11∑- g, which shows the spin polarization effect of Tc2 molecule of a transition metal element for the first time.Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc2 molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc2 molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization.In addition, the Murrell-Sorbie potential functions with the parameters for the ground state 11∑- g and other states of Tc2 molecule are derived. Dissociation energy De for the ground state of Tc2 molecule is 2.266eV, equilibrium bond length Re is 0.2841nm, vibration frequency ωe is 178.52cm-1. Its force constants f2, f3, and f4 are 0.9200aJ.nm-2,-3.5700aJ.nm-3, 11.2748aJ.nm-4 respectively. The other spectroscopic data for the ground state of Tc2 molecule ωexe,Be, αe are 0.5523cm- 1, 0.0426cm- 1, 1.6331 × 10-4cm- 1 respectively.

  15. Impact of curie-therapy timing in the treatment of cervical cancer; Impact du timing de la curietherapie dans le traitement du cancer du col uterin

    Energy Technology Data Exchange (ETDEWEB)

    Kochbati, L.; Bouzid, N.; Saidi, I.; Nasr, C.; Messai, T.; Hentati, D.; Gargouri, W.; Besbes, M.; Maalej, M. [Service de radiotherapie, institut Salah-Azaiz, Tunis (Tunisia)

    2011-10-15

    Curie-therapy conventionally comes before surgery in the treatment of cervical cancer, either alone or after a concomitant chemotherapy. The authors report a study of the impact of a reverse sequence (surgery before curie-therapy) on the exeresis quality and on the evolution of operable tumours. Among women treated between 2004 and 2009, 40 have been identified who had surgery before curie-therapy. Ages, tumour stages, average doses, and treatment procedures are discussed. The notably high rate of vaginal sections could be reduced or avoided by using the conventional protocol (curie-therapy before surgery). Short communication

  16. The Evidence of Phase Separation in Perovskite Manganites Above Tc

    Institute of Scientific and Technical Information of China (English)

    TIAN Hong-wei; ZANG Jian-Feng; DING Tao; ZHENG Wei-tao; WANG Xin

    2004-01-01

    A series of bulk ceramic samples of La1-xCaxMnO3 and Y1-xCaxMnO3 was prepared by the conventional solid state reaction method,and the samples of x=1/3 were investigated particularly.The colossal magnetoresistance phenomenon and the properties of magnetic and transport were studied in detail by the experiments of magnetic susceptibility and low temperature resistance.Small angle X-ray scattering (SAXS) was used to investigate the charge inhomogeneities in our samples at room temperature for the first time,and phase separation and colossal magnetoresistance phenomena induced by charge inhomogeneities above Tc were discovered.

  17. [Maria Skłodowska-Curie--her chemistry at the centenary of the second Nobel Prize].

    Science.gov (United States)

    Zagórski, Zbigniew Paweł; Kornacka, Ewa Maria

    2012-01-01

    The article presents from the perspective of one hundred years the work of Maria Curie-Skłodowska, which in many cases was ahead of the state of knowledge of the time. It opened new horizons and for this reason we made many digressions. The fact of awarding her the Nobel Prize twice is a sensation enough to present the values of careful activity of the Nobel Prize Committee that emphasizes the importance of Maria's achievements. A significant element of Maria Skłodowska-Curie's achievements was still mysterious character of the radiation in her time, and only chemical approach made it possible to organise the phenomena and explain the origin of the radiation. The essence of the research was an arduous separation of components following the track of growing radiation of successive fractions of preparations. This research was a start of the technology of educement of dispersed elements in great mass of materials. We underline the paramount role of the chemical research Maria Skłodowska conducted while still in Warsaw in the laboratories of the Museum of Industry and Agriculture under the guidance of an excellent chemist Józef Jerzy Boguski. Her research in Paris was the origin of the semi-commercial scale in chemistry and setting aside a special shed outside the university building was the beginning of the institutes that now function beyond universities and are key element of scientific and technical progress. Technology of splitting developed by Maria Skłodowska-Curie was applied also by other radiochemists, e.g. By Otto Hahn. Lively movement in radiochemistry of her lifetime resulted in Maria's disputes with e.g. German chemist Marckwald, who questioned the originality of polonium. The scientific disputes like this one Maria won triumphantly although in several others she had to accept opponents' argument, as in the case of radon. Her experiments were planned with utmost rationality as it was with the rejection of the hypothesis saying that radioactivity was

  18. Standards of radium-226: from Marie Curie to the International Committee for Radionuclide Metrology.

    Science.gov (United States)

    Coursey, B M; Collé, R; Coursey, J S

    2002-01-01

    In the early part of the 20th century, the pioneers of radioactivity research, led by Marie Curie, Ernest Rutherford and Stefan Meyer, formed a Commission internationale des étalons de radium. The Commission made arrangements for the preparation and intercomparisons of the international standards of radium, which were identified as the Paris standard and the Vienna standard. Otto Hönigschmid from Vienna prepared a first set of international secondary standards in 1912 and a second set in 1934. In both instances, these secondary standards were compared by gamma-ray measurements with the Paris and Vienna standards. The usage of these international standards of radium in the 20th century is described.

  19. Temperature dependent changes of the Mn 3d and 4p bands near $T_{c}$ in Colossal Magnetoresistance systems : a XANES study of $La_{1-x}Ca_{x}MnO_{3}$

    NARCIS (Netherlands)

    Bridges, F; Booth, C. H.; Kwei, G. H.; Neumeier, J. J.; Sawatzky, G. A.

    2000-01-01

    Abstract: We report high-resolution X-ray Absorption Near Edge Structure (XANES)measurements at the Mn K-edge as a function of temperature, forLa$_{1-x}$Ca$_x$MnO$_3$ samples, with a focus mainly on the pre-edge region.Small peaks labeled A$_1$-A$_3$ are observed which corresponds to

  20. Use of 99mTc from a commercial 99Mo/9mTc generator as yield tracer for the determination of 99Tc at low levels

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Jensen, Mikael; Nielsen, Sven Poul

    2007-01-01

    cartridges was investigated to purify the eluate to obtain a suitable Tc-99m tracer with low Tc-99 concentration. The activity ratio of Tc-99/Tc-99m in the prepared Tc-99m solution is lower than 15 x 10(-9), which is higher than the theoretical ratio of less than 10 x 10(-9). The possible reason is discussed......) 2007 Elsevier Ltd. All rights reserved....

  1. A new family of high-Tc compounds-Stepping stones toward understanding unconventional superconductivity

    Institute of Scientific and Technical Information of China (English)

    SUN Yang; Mike GUIDRY; WU ChengLi

    2008-01-01

    @@ High-transition temperature (Tc) superconductivity was first discovered in layered copper-based oxides (cuprates)more than two decades ago[1], but its theoretical inter-pretation remains controversial[2,3]. The main question concerning the high-Tc superconductivity phase diagram is the transition between the antiferromagnetic (AF) and superconducting (SC) phases, which is dominated by anomalous properties commonly attributed to a pseu-dogap[4,5] in the spectrum. It is believed that the high-Tc mechanism in cuprates cannot be fully understood within the BCS theory[6] that explains normal supercon-ductivity. Despite much effort, there is no consensus as to the origin of the pseudogap properties, and the high-Tc mechanism remains an open question.

  2. Continuous-Flow Inlet Systems for Low Pressure Curie-Point Pyrolysis. Introduction of Pulse-Pyrolysis

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Carlsen, Lars

    1984-01-01

    With emphasis on a constant reactant flow, a series of inlet systems for gas-phase Curie-point pyrolysis—mass spectrometry experiments have been studied. Inlet systems for the handling of gaseous, liquid and oligomeric (solid) samples have been designed and their performances evaluated. The princ....... The principle of pulse-pyrolysis is introduced and its applicability to kinetic studies outlined....

  3. Spin-flip dynamics of the Curie-Weiss model : Loss of Gibbsianness with possibly broken symmetry

    NARCIS (Netherlands)

    Kulske, Christof; Le Ny, Arnaud

    2007-01-01

    We study the conditional probabilities of the Curie-Weiss Ising model in vanishing external field under a symmetric independent stochastic spin-flip dynamics and discuss their set of points of discontinuity (bad points). We exhibit a complete analysis of the transition between Gibbsian and non-Gibbs

  4. Formalizing BPEL-TC Through ?-Calculus

    Directory of Open Access Journals (Sweden)

    Preeti Marwaha

    2013-07-01

    Full Text Available WS-BPEL is way to define business processes that interact with external entities through webservice operations using WSDL. We have proposed BPEL-TC, an extension to existing WS-BPEL whichuses temporally customized Web Services (WSDL-TC as a model for process decomposition and assembly.WSDL-TC handles both backward compatible and incompatible changes and also maintains variousversions of the artifacts that results due to changes over time and customizations desired by the users. Inthis paper, we are using pi-calculus to formalize Business Process Execution Language- TemporalCustomization (BPEL-TC process. π -calculus is a model of computation for concurrent systems alongwith changing connectivity of interactive systems. Pi-calculus is an extension of the process algebra CCS,with added mobility to CCS while preserving its algebraic properties.

  5. Flexible PVDF ferroelectric capacitive temperature sensor

    KAUST Repository

    Khan, Naveed

    2015-08-02

    In this paper, a capacitive temperature sensor based on polyvinylidene fluoride (PVDF) capacitor is explored. The PVDF capacitor is characterized below its Curie temperature. The capacitance of the PVDF capacitor changes vs temperature with a sensitivity of 16pF/°C. The linearity measurement of the capacitance-temperature relation shows less than 0.7°C error from a best fit straight line. An LC oscillator based temperature sensor is demonstrated based on this capacitor.

  6. Direct 99m Tc labeling of Herceptin (trastuzumab) by 99m Tc(I) tricarbonyl ion.

    Science.gov (United States)

    Chen, Wan-Jou; Yen, Chao-Liang; Lo, Su-Tang; Chen, Kuo-Ting; Lo, Jem-Mau

    2008-03-01

    By simply incubating Herceptin (trastuzumab) with [99m Tc(CO)3(OH2)3]+ ion in saline, a significant yield of 99m Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which 99m Tc(I) tricarbonyl ion can be strongly bound. For practical 99m Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, alpha-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [99m Tc(CO)3(OH2)3]+. Retention of bioactivity of the 99m Tc(I)-labeled trastuzumab was validated using a cell binding test.

  7. High Tc superconducting fabrication of loop antenna

    Directory of Open Access Journals (Sweden)

    Widad Mahmood Faisal

    2012-09-01

    Full Text Available Using a solid state reaction to prepared many samples of YBa2Cu3O7−δ And (YBa2Cu3O7−δ1−x(Ag2Ox by mixing the appropriate ratios of constituent oxides; BaO, CuO, and Y2O3 the mixture were ground to fine power and then calcined at 900 °C without Ag2O and 930 °C for using Ag2O as impurities. The calcined black power were grounded again and molded into pellets by applying a hydrostatic pressure from (0.3–0.6 Gpa. These pellets were sintered at 950 °C. Silver was added as impurities with the calcined powder with ratios of 0.3, 0.35 and 0.45 to increase its ductility. The transition temperature for the superconductor samples were done using non-contact technique. It is an easy and sensitive technique compared with four – point probe method. The maximum Tc was 110 K for YBa2Cu3O6.989. Evaporation deposition technique to deposited a thin film, of 2200 A° thickness on the surface of the samples and then annealed to room temperature. This technical reduces the resistance to 0.2 Ω and makes a good ohmic contact at liquid nitrogen boiling point (77 K metals of various conductivity such as copper, brass aluminum and iron were used to study the effect of eddy-current loss on them and then compared with the superconducting samples, with Ag2O or without Ag2O. The maximum power loss were obtained for the superconducting samples when they cooling at liquid nitrogen temperature. The sintered pellets were drilled manually by 6 mm drill and a slot was done along its radius, to fabricate a superconducting loop antenna for receiving magnetic field signal. The best received signal was obtained when the antenna cooled to liquid nitrogen temperature.

  8. Fusion neutron irradiation of Ni(Si) alloys at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.S.; Guinan, M.W.; Hahn, P.A.

    1987-09-01

    Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab.

  9. Power Systems Development Facility Gasification Test Run TC08

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2002-06-30

    This report discusses Test Campaign TC08 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier in air- and oxygen-blown modes during TC08. Test Run TC08 was started on June 9, 2002 and completed on June 29. Both gasifier and PCD operations were stable during the test run with a stable baseline pressure drop. The oxygen feed supply system worked well and the transition from air to oxygen blown was smooth. The gasifier temperature was varied between 1,710 and 1,770 F at pressures from 125 to 240 psig. The gasifier operates at lower pressure during oxygen-blown mode due to the supply pressure of the oxygen system. In TC08, 476 hours of solid circulation and 364 hours of coal feed were attained with 153 hours of pure oxygen feed. The gasifier and PCD operations were stable in both enriched air and 100 percent oxygen blown modes. The oxygen concentration was slowly increased during the first transition to full oxygen-blown operations. Subsequent transitions from air to oxygen blown could be completed in less than 15 minutes. Oxygen-blown operations produced the highest synthesis gas heating value to date, with a projected synthesis gas heating value averaging 175 Btu/scf. Carbon conversions averaged 93 percent, slightly lower than carbon conversions achieved during air-blown gasification.

  10. Power Systems Development Facility Gasification Test Campaign TC24

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-03-30

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC24, the first test campaign using a bituminous coal as the feedstock in the modified Transport Gasifier configuration. TC24 was conducted from February 16, 2008, through March 19, 2008. The PSDF gasification process operated for about 230 hours in air-blown gasification mode with about 225 tons of Utah bituminous coal feed. Operational challenges in gasifier operation were related to particle agglomeration, a large percentage of oversize coal particles, low overall gasifier solids collection efficiency, and refractory degradation in the gasifier solids collection unit. The carbon conversion and syngas heating values varied widely, with low values obtained during periods of low gasifier operating temperature. Despite the operating difficulties, several periods of steady state operation were achieved, which provided useful data for future testing. TC24 operation afforded the opportunity for testing of various types of technologies, including dry coal feeding with a developmental feeder, the Pressure Decoupled Advanced Coal (PDAC) feeder; evaluating a new hot gas filter element media configuration; and enhancing syngas cleanup with water-gas shift catalysts. During TC24, the PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane.

  11. PREFACE: 2014 Joint IMEKO TC1-TC7-TC13 Symposium: Measurement Science Behind Safety and Security

    Science.gov (United States)

    Sousa, João A.; Ribeiro, Álvaro S.; Filipe, Eduarda

    2015-02-01

    The 2014 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium was organized by RELACRE - Portuguese Association of Accredited Laboratories and the Portuguese Society for Metrology, on 3-5 September 2014. The work of this symposium is reported in this volume. The scope of the symposium includes the main topics covered by the above Technical Committees: - TC1 Education and Training in measurement and Instrumentation - TC7 Measurement Science - TC13 Measurements in Biology and Medicine The effort towards excellence of previous events, in this well established series, is maintained. There has been a special focus on measurement science behind safety and security, with the aim of highlighting the interdisciplinary character of measurement science and the importance of metrology in our daily lives. The discussion was introduced by keynote lectures on measurement challenges in biometrics, health monitoring and social sciences, to promote useful interactions with scientists from different disciplines. The Symposium was attended by experts working in these areas from 18 countries, including USA, Japan and China, and provided a useful forum for them to share and exchange their work and ideas. In total over fifty papers are included in the volume, organized according to the presentation sessions. Each paper was independently peer-reviewed by two reviewers from a distinguished international panel. The Symposium was held in Funchal, capital of Madeira Islands, known as the Atlantic Pearl. This wonderful Atlantic archipelago, formed by Madeira and Porto Santo islands, discovered in the 14th century, was chosen to host the 2014 IMEKO TC1-TC7-TC13 Joint Symposium ''Measurement Science behind Safety and Security''. It was the first territory discovered by the Portuguese sailors, when set out to discover a new world, in an epic journey where instrumentation and quality of measurement played a central role in the success of the enterprise, and gave an

  12. Determination of Tc-99 in radioactive wastes; Determinacion de Tc-99 en desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rivera S, A. A.

    2015-07-01

    Tc-99 is a fission product and one of the most important radionuclides from the view point of safety assessment for the disposal of radioactive waste because of its long half-life (2.1 x 10{sup 5} years) and high mobility in soil-water systems, if this is released into the environment in significant quantities can concentrate on plants and animals. Tc-99 is a pure beta emitter with a maximum energy of 292 KeV, so their quantification imposes destructive methods to be analyzed by liquid scintillation. Therefore the quantification of Tc-99 in ion exchange resins requires of the mineralization of these and separation of Tc-99 of other radioisotopes present in the resin. Therefore the object of this thesis is to develop a quantification method of Tc-99 content in spent exchange resins. So in order to track the behavior of technetium during digestion exchange resins and radiochemical separation, given its high volatility, in this work the {sup 99m}Tc is used. To determine the degree of mineralization of the resins, an analysis was performed by chromatography. Subsequently the method used to determine the percentage of {sup 99m}Tc aerosolized during mineralization of resin is described. After the method for the radiochemical separation of {sup 99m}Tc is presented by liquid-liquid extraction using crown ether as extractant; for this testing was performed by varying the molarity of the extractant, the ratio of solvent extractant, type of digestion of the resin and the presence of Sr-85, in order to study the behavior of {sup 99m}Tc in the presence of this radioisotope. Finally, a track beta spectra of a sample of {sup 99m}Tc eluted from a generator {sup 99}Mo/{sup 99m}Tc function of time was performed. (Author)

  13. Applications using high-Tc superconducting terahertz emitters

    Science.gov (United States)

    Nakade, Kurama; Kashiwagi, Takanari; Saiwai, Yoshihiko; Minami, Hidetoshi; Yamamoto, Takashi; Klemm, Richard A.; Kadowaki, Kazuo

    2016-03-01

    Using recently-developed THz emitters constructed from single crystals of the high-Tc superconductor Bi2Sr2CaCu2O8+δ, we performed three prototype tests of the devices to demonstrate their unique characteristic properties for various practical applications. The first is a compact and simple transmission type of THz imaging system using a Stirling cryocooler. The second is a high-resolution Michelson interferometer used as a phase-sensitive reflection-type imaging system. The third is a system with precise temperature control to measure the liquid absorption coefficient. The detailed characteristics of these systems are discussed.

  14. Irradiation-induced disorder in high- Tc cuprates: electronic band structure study

    Science.gov (United States)

    Vobornik, I.; Quitmann, C.; Zacchigna, M.; Zwick, F.; Grioni, M.; Karkin, A.; Kelley, R. J.; Onellion, M.; Margaritondo, G.

    1998-05-01

    We used thermal neutron irradiation to produce disorder in Bi-2212 single crystals ( TC=85 K), at a constant carrier density. The irradiated samples were insulators. High-temperature superconductivity with a lower TC than prior to irradiation could be restored by a low-temperature annealing. We performed angle-resolved photoemission investigation on both unannealed (insulating) and annealed (superconducting) samples in order to study the corresponding changes in electronic structure. We observed a strong suppression of the spectral weight near the Fermi energy with increasing disorder. Our results demonstrate that effects related to disorder cannot be neglected in the interpretation of the spectral properties of cuprates.

  15. Curie isotherm map of Scotia Arc from near surface magnetic anomaly data

    Science.gov (United States)

    Catalán, Manuel

    2016-04-01

    The opening of the Drake Passage, situated between South America and Antarctica, represents the final stage of the fragmentation of Gondwana supercontinent. It led to the Scotia Arc formation, bordering the Scotia Sea, which is surrounded by fragments of the former continental connection. It is currently composed of Scotia and Sandwich Plates. Shackleton Fracture Zone constitutes its sinistral transpressive western boundary and it is a key structure that accommodates former Phoenix and Scotia Plates' differential movement. The formation of the Drake Passage and the Scotia Sea is considered of great importance to ocean circulation, as it allows the establishment of the Antarctic Circumpolar Current that isolated the Antarctic continent, with strong implications for climate and global changes. Thermal structure of the Earth's crust is one of the main parameters controlling geodynamic processes. There is few information regarding heat flow values on Scotia arc. These values are mainly located in its westernmost, southern and easternmost part, which are not enough to extract conclusions regarding lithospheric thickness variations and asthenospheric flow. Taking advantage of the World Digital Magnetic Anomaly Map Project's compilation we have extracted magnetic anomaly data which fall inside the Scotia Arc and surrounding areas. This magnetic anomaly picture provides the best representation of magnetic properties to date. We propose to use spectral methods on this regional magnetic compilation to obtain depth to the bottom of magnetic sources as a proxy to infer Curie depth and heat flow distribution in the Scotia Sea.

  16. [Analytical chemistry in works of Maria Skłodowska-Curie].

    Science.gov (United States)

    Hulanicki, Adam

    2012-01-01

    Maria Skłodowska-Curie--a Nobel Prize winner in chemistry--the elements of learning of chemistry gained just by a dint of work of more than ten months in Warsaw in the Institute of Industry and Agriculture Museum. The Nobel Prize concerned a contribution to the progress of chemistry through the discovery of radium and polonium, separation of radium and study of properties of this amazing element. It was awarded for an extremely arduous work, during which the chemical reactions being the principles of analytical chemistry were realized. Unlike to a typical analytical procedure, an initial attempt here was the thousands of kilograms of uranium ore: pitchblende. The final effect was small amounts of new elements: polonium and radium. Both the knowledge and the intuition of the researcher let her have a triumph. The difficulties she experienced because the properties of the searched chemical elements could only be evaluated thanks to the knowledge on other chemical elements. A significant achievement was the determination of the samples by means of radioactivity measurement, which gave rise to radiochemical analytical methods. An extreme analytical precision was demanded in multiple processes of fractional crystallization and precipitation which finally led to the calculation of the atomic mass of radium.

  17. Developing translational medicine professionals: the Marie Skłodowska-Curie action model.

    Science.gov (United States)

    Petrelli, Alessandra; Prakken, Berent J; Rosenblum, Norman D

    2016-11-29

    End goal of translational medicine is to combine disciplines and expertise to eventually promote improvement of the global healthcare system by delivering effective therapies to individuals and society. Well-trained experts of the translational medicine process endowed with profound knowledge of biomedical technology, ethical and clinical issues, as well as leadership and teamwork abilities are essential for the effective development of tangible therapeutic products for patients. In this article we focus on education and, in particular, we discuss how programs providing training on the broad spectrum of the translational medicine continuum have still a limited degree of diffusion and do not provide professional support and mentorship in the long-term, resulting in the lack of well established professionals of translational medicine (TMPs) in the scientific community. Here, we describe the Marie Skłodowska-Curie Actions program ITN-EUtrain (EUropean Translational tRaining for Autoimmunity & Immune manipulation Network) where training on the Translational Medicine machinery was integrated with education on professional and personal skills, mentoring, and a long-lasting network of TMPs.

  18. Developing spiritual and religious care competencies in practice: pilot of a Marie Curie blended learning event.

    Science.gov (United States)

    Smith, Tracy; Gordon, Tom

    2009-02-01

    The Marie Curie Cancer Care (2003) Spiritual and Religious Care Competencies for Specialist Palliative Care provide a common language for healthcare practitioners in the nebulous area of spiritual care. The development of a pilot blended learning event, as described in this paper, sought to integrate the competencies into practice by providing opportunities both online and in the classroom to explore this aspect of holistic care in depth. In the planning stages, multiprofessional focus groups determined the level of delivery, and emerging themes shaped the content. Self-awareness and reflection were key features and part of the overall process to improve competency. The features of the virtual learning environment (VLE) used were video, facilitated asynchronous discussion and direct links to key articles and documents, while interactive classroom activities built on prior learning. Evaluation covered all aspects of the course design from participant and facilitator perspectives. Participant comments were overwhelmingly positive in relation to the content and chosen delivery methods with concerns about online learning proving unfounded.

  19. Magnetocaloric effect in temperature-sensitive magnetic fluids

    Indian Academy of Sciences (India)

    Kinnari Parekh; R V Upadhyay; R V Mehta

    2000-04-01

    The magnetocaloric properties of three different temperature-sensitive magnetic fluids were studied. The pyromagnetic coefficient for all the materials were obtained and it was found that this property depends on physical and magnetic properties like size, magnetization and Curie temperature. A theoretical model was developed to explain the behaviour of change in entropy with temperature.

  20. Thymidine kinase enzyme selective imaging radiopharmaceutical. {sup 99m}Tc(CO){sub 3}-Ganciclovir

    Energy Technology Data Exchange (ETDEWEB)

    Gedik, B.; Teksoez, S.; Ichedef, C.; Kilcar, A.Y.; Medine, E.I.; Ucar, E. [Ege Univ., Bornova, Izmir (Turkey). Dept. of Nuclear Applications

    2013-03-01

    The aim of this study is to radiolabel Ganciclovir, known as having selective antiviral properties against thymidine kinase, with technetium tricarbonylcore ({sup 99m}Tc(CO){sub 3}{sup +}) and to investigate the biological behavior of this complex in vitro and in vivo. Commercially provided Ganciclovir (GCV) was radiolabeled with {sup 99m}Tc(CO){sub 3}{sup +}. Initially, optimum radiolabeling conditions were determined by analyzing factors such as temperature, pH and time. Quality control of the radiolabeled compound was performed. The radiolabeling yield was found to be 97%. The {sup 99m}Tc(CO){sub 3}-GCV complex also displayed good in vitro stability during the 24 h period. In vitro cell uptake studies showed that the {sup 99m}Tc(CO){sub 3}-GCV complex is highly uptaken in A-549, PC-3, HeLa cell lines according to the control group {sup 99m}Tc(I)-tricarbonyl core. The knowledge gained from in vivo and in vitro studies of {sup 99m}Tc(CO){sub 3}-GCV could contribute to the development of a new HSV1-tk gene imaging agent. (orig.)

  1. Finite Element Research on Cutting Force and Cutting Temperature in Cutting Hydrogenated Ti- 6Al- 4V Titanium Alloy%切削置氢TC4钛合金切削力及切削温度的有限元分析

    Institute of Scientific and Technical Information of China (English)

    杨树宝; 徐九华; 傅玉灿; 危卫华

    2011-01-01

    The present study is undertaken to investigate the effect of hydrogen on the cutting force and cutting temperature of Ti - 6Al - 4V alloy by FEM, and the tendency at higher cutting speed is predicted. Mechanical behaviors of hydrogenated Ti - 6Al -4V alloy are studied at elevated temperatures and high strain rates with split Hopkinson pressure bar (SHPB ).The Johnson-Cook model is developed combined with quasi-static experimental data. A numerical model is developed to simulate the cutting process.The results of the experiments and simulations correlate well. The results demonstrate that the presence of hydrogen has a significant effect on the cutting forces and temperature, and the cutting forces and temperature increase first and then decreased gradually with the increasing of hydrogen contents. The simulation results show that titanium alloys with 0.3 % hydrogen has better machinability.In addition, the effect of hydrogen on cutting force and cutting temperature at high cutting speed is weaker than at low speed.%利用有限元技术,研究了氢含量对TC4钛合金切削力及切削温度的影响规律,并对高速切削时的切削力、切削温度的规律进行了预测.利用电子万能材料试验机及霍普金森压杆装置获取了不同应变速率及温度时置氢钛合金的流变行为,通过数据的拟合得到了Johnson-Cook(J-C)本构方程,据此建立了切削数值模型.切削力及切削温度的模拟结果与试验数据对比表明,所建立的有限元模型能够较准确地反映切削过程.切削力及切削温度均随着氢含量的增加而呈现先减小后增加的相似规律,氢含量为0.3%时其所对应的切削力及切削温度均最低;高速切削下氢含量对切削力及切削温度的影响较低速时弱.

  2. Synthesis and Characterization of Tc(I) Carbonyl Nitrosyl Species Relevant to the Hanford Tank Waste: FY 2016 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Martin, Thibaut J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Nathalie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-24

    Among long-lived radioactive constituents in the Hanford tank waste, Tc presents a unique challenge in that it exists predominantly in the liquid phase, generally in the anionic form of pertechnetate, TcO4-, which is highly volatile at low-activity waste (LAW) vitrification melter temperatures and mobile in the Hanford site’s subsurface environment. The complex behavior of Tc under storage, treatment, and immobilization conditions significantly affects its management options, which to-date remain uncertain. In strongly alkaline environments, Tc exists as pertechnetate, TcO4- (oxidation state +7), and in the reduced forms (oxidation state < +7) collectively known as non-pertechnetate species. Pertechnetate is a well-characterized, anionic Tc species that can be removed from LAW by anion exchange or solvent extraction methods. There is no definitive information on the origin of the non-pertechnetate Tc species, nor is there a comprehensive description of their composition and behavior. It has been recently proposed that the non-pertechnetate species can comprise Tc(I) metal center and carbonyl or mixed carbonyl nitrosyl ligands stabilizing low-valent Tc. Recent work by our group has significantly expanded this previous work, generating a series of Tc(I) carbonyl compounds and demonstrating that they can be generated from reduction of TcO4- in the simulated Hanford tank waste in presence of CO at elevated temperature (Levitskaia et al. 2014). These results are consistent with the previous proposal that [Tc(CO)3]+ species can be present in the Hanford tank waste and suggest that the low Tc(I) oxidation state is stabilized by the π-accepting ability of the CO ligands. The continuation work has been initiated to develop model Tc carbonyl nitrosyl compounds and investigate their potential presence in the Hanford tank wastes. This report summarizes our to-date results.

  3. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

    2014-01-01

    Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

  4. Enhanced room temperature magnetoresistance in maganites La0.60Sr0.25-yNa0.15Δy MnO 31

    Institute of Scientific and Technical Information of China (English)

    TANG Guide; ZHAO Fuwei; LI Zhuangzhi; HOU Denglu; ZHAO Xu; LI Zhiqing

    2006-01-01

    Bulk polycrystalline samples of La0.60Sr0.4MnO3 and La0.60Sr0.25-yNa0.15ΔyMnO3 with 0.00≤ y ≤0.15 ("Δ" representing cation vacancy) were successfully synthesized using the sol-gel method. The structural, magnetic, and electrical properties of the polycrystallineof the samples were investigated. The results of X-ray powder diffraction patterns show that these compounds crystallize in a distorted rhombohedral structure with the space group R(3)C . The measurement shows that, with vacancy content y increasing, the unit cell volume V of samples increases, furthermore, the Curie temperature TC decreases. The temperature dependence of resistivity shows that all samples undergo a metal-semiconductor transition accompanying a ferromagnetic to paramagnetic transition with the increase of temperature. Under an applied filed of 1.8 T, a maximum room temperature magnetoresistance ( MR ) of 20% is obtained at 293 K for the compound La0.60Sr0.1Na0.15Δ0.15MnO3. The MR peak value of La0.60Sr0.1Na0.15Δ0.15MnO3 increases2 times more than that of La0.60Sr0.40MnO3 ( MRP=6.4%, TMR =373 K), and the MR peak is shifted from 373 K to room temperature.

  5. Hot Plate Annealing at a Low Temperature of a Thin Ferroelectric P(VDF-TrFE Film with an Improved Crystalline Structure for Sensors and Actuators

    Directory of Open Access Journals (Sweden)

    Rahman Ismael Mahdi

    2014-10-01

    Full Text Available Ferroelectric poly(vinylidene fluoride-trifluoroethylene (P(VDF-TrFE copolymer 70/30 thin films are prepared by spin coating. The crystalline structure of these films is investigated by varying the annealing temperature from the ferroelectric phase to the paraelectric phase. A hot plate was used to produce a direct and an efficient annealing effect on the thin film. The dielectric, ferroelectric and pyroelectric properties of the P(VDF-TrFE thin films are measured as a function of different annealing temperatures (80 to 140 °C. It was found that an annealing temperature of 100 °C (slightly above the Curie temperature, Tc has induced a highly crystalline β phase with a rod-like crystal structure, as examined by X-ray. Such a crystal structure yields a high remanent polarization, Pr = 94 mC/m2, and pyroelectric constant, p = 24 μC/m2K. A higher annealing temperature exhibits an elongated needle-like crystal domain, resulting in a decrease in the crystalline structure and the functional electrical properties. This study revealed that highly crystalline P(VDF-TrFE thin films could be induced at 100 °C by annealing the thin film with a simple and cheap method.

  6. Hot plate annealing at a low temperature of a thin ferroelectric P(VDF-TrFE) film with an improved crystalline structure for sensors and actuators.

    Science.gov (United States)

    Mahdi, Rahman Ismael; Gan, W C; Abd Majid, W H

    2014-10-14

    Ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer 70/30 thin films are prepared by spin coating. The crystalline structure of these films is investigated by varying the annealing temperature from the ferroelectric phase to the paraelectric phase. A hot plate was used to produce a direct and an efficient annealing effect on the thin film. The dielectric, ferroelectric and pyroelectric properties of the P(VDF-TrFE) thin films are measured as a function of different annealing temperatures (80 to 140 °C). It was found that an annealing temperature of 100 °C (slightly above the Curie temperature, Tc) has induced a highly crystalline β phase with a rod-like crystal structure, as examined by X-ray. Such a crystal structure yields a high remanent polarization, Pr = 94 mC/m2, and pyroelectric constant, p = 24 μC/m2K. A higher annealing temperature exhibits an elongated needle-like crystal domain, resulting in a decrease in the crystalline structure and the functional electrical properties. This study revealed that highly crystalline P(VDF-TrFE) thin films could be induced at 100 °C by annealing the thin film with a simple and cheap method.

  7. A pixel ionization chamber used as beam monitor at the Institut Curie-Centre de Protontherapie de Orsay (CPO)

    Energy Technology Data Exchange (ETDEWEB)

    La Rosa, A. [Dipartimento di Fisica Sperimentale, Universita di Torino. Via P. Giuria 1, Torino 10125 (Italy) and INFN. Via P. Giuria 1, Turin 10125 (Italy)]. E-mail: larosa@to.infn.it; Garella, M.A. [INFN. Via P. Giuria 1, Turin 10125 (Italy); Bourhaleb, F. [Fondazione TERA. Via Puccini 11, Novara 28100 (Italy); Cirio, R. [INFN. Via P. Giuria 1, Turin 10125 (Italy); Donetti, M. [INFN. Via P. Giuria 1, Turin 10125 (Italy); Fondazione CNAO. Via Caminadella 16, Milan 20123 (Italy); Giordanengo, S. [INFN. Via P. Giuria 1, Turin 10125 (Italy); Givehchi, N. [Dipartimento di Fisica Sperimentale, Universita di Torino. Via P. Giuria 1, Turin 10125 (Italy); INFN. Via P. Giuria 1, Turin 10125 (Italy); Marchetto, F. [INFN. Via P. Giuria 1, Turin 10125 (Italy); Martin, F. [Institut Curie-Centre de Protontherapie de Orsay. Bat. 101 Campus Universitaire, Orsay Cedex 91898 (France); Meyroneinc, S. [Institut Curie-Centre de Protontherapie de Orsay. Bat. 101 Campus Universitaire, Orsay Cedex 91898 (France); Peroni, C. [Dipartimento di Fisica Sperimentale, Universita di Torino. Via P. Giuria 1, Turin 10125 (Italy); INFN. Via P. Giuria 1, Turin 10125 (Italy); Pitta, G. [Fondazione TERA. Via Puccini 11, Novara 28100 (Italy)

    2006-09-15

    The Dipartimento di Fisica Sperimentale and the Istituto Nazionale di Fisica Nucleare (INFN), Torino, in collaboration with the Institut Curie-Centre de Protontherapie de Orsay (CPO), have developed and built a pixel parallel plate ionization chamber to be used as monitor for the proton therapy beam line at the Institut Curie-CPO (Orsay, France). The sensitive area of the detector is (160x160) mm{sup 2}, with the anode segmented in 1024 square pixels arranged in a 32x32 matrix; the area of each pixel is (5x5) mm{sup 2}. The detector has been placed on the beam line just upstream of the last collimator to monitor the beam shape and to measure the stability and reproducibility of the delivery system. In this paper, we present a detailed description of the detector and the results of a set of preliminary tests.

  8. Curie point depth from spectral analysis of aeromagnetic data from Cerro Prieto geothermal area, Baja California, México

    Science.gov (United States)

    Espinosa-Cardeña, J. M.; Campos-Enriquez, J. O.

    2008-10-01

    Using aeromagnetic data acquired in the area from the Cerro Prieto geothermal field, we estimated the depth to the Curie point isotherm, interpreted as the base of the magnetic sources, following statistical spectral-based techniques. According to our results the Curie point isotherm is located at a depths ranging from 14 to 17 km. Our result is somewhat deeper than that obtained previously based only in 2-D and 3-D forward modeling of previous low-quality data. However, our results are supported by independent information comprising geothermal gradients, seismicity distribution in the crust, and gravity determined crustal thickness. Our results imply a high thermal gradient (ranging between 33 and 38 °C/km) and high heat flow (of about 100 mW/m 2) for the study area. The thermal regime for the area is inferred to be similar to that from the Salton trough.

  9. Tropical Cyclone Prediction Using COAMPS-TC

    Science.gov (United States)

    2014-09-01

    Oceanography | Vol. 27, No.3104 S P E C I A L I S S U E O N N AV Y O P E R AT I O N A L M O D E L S Tropical Cyclone Prediction Using COAMPS...Ocean/ Atmosphere Mesoscale Prediction System for Tropical Cyclones (COAMPS®-TC) has been developed for prediction of tropical cyclone track, structure...and intensity. The COAMPS-TC has been tested in real time in both uncoupled and coupled modes over the past several tropical cyclone seasons in

  10. CTLA-4 (CD152) enhances the Tc17 differentiation program.

    Science.gov (United States)

    Pick, Jonas; Arra, Aditya; Lingel, Holger; Hegel, J Kolja; Huber, Magdalena; Nishanth, Gopala; Jorch, Gerhard; Fischer, Klaus-Dieter; Schlüter, Dirk; Tedford, Kerry; Brunner-Weinzierl, Monika C

    2014-07-01

    Although CD8(+) T cells that produce IL-17 (Tc17 cells) have been linked to host defense, Tc17 cells show reduced cytotoxic activity, which is the characteristic function of CD8(+) T cells. Here, we show that CTLA-4 enhances the frequency of IL-17 in CD8(+) T cells, indicating that CTLA-4 (CD152) specifically promotes Tc17 differentiation. Simultaneous stimulation of CTLA-4(+/+) and CTLA-4(-/-) T cells in cocultures and agonistic CTLA-4 stimulation unambiguously revealed a cell-intrinsic mechanism for IL-17 control by CTLA-4. The quality of CTLA-4-induced Tc17 cells was tested in vivo, utilizing infection with the facultative intracellular bacterium Listeria monocytogenes (LM). Unlike CTLA-4(+/+) Tc17 cells, CTLA-4(-/-) were nearly as efficient as Tc1 CTLA-4(+/+) cells in LM clearance. Additionally, adoptively transferred CTLA-4(-/-) Tc17 cells expressed granzyme B after rechallenge, and produced Tc1 cytokines such as IFN-γ and TNF-α, which strongly correlate with bacterial clearance. CTLA-4(+/+) Tc17 cells demonstrated a high-quality Tc17 differentiation program ex vivo, which was also evident in isolated IL-17-secreting Tc17 cells, with CTLA-4-mediated enhanced upregulation of Tc17-related molecules such as IL-17A, RORγt, and IRF-4. Our results show that CTLA-4 promotes Tc17 differentiation that results in robust Tc17 responses. Its inactivation might therefore represent a central therapeutic target to enhance clearance of infection.

  11. Theoretical prediction of antiferromagnetism in layered perovskite Sr2TcO4

    Science.gov (United States)

    Horvat, Alen; Pourovskii, Leonid; Aichhorn, Markus; Mravlje, Jernej

    2017-05-01

    We theoretically investigate the magnetic properties of Sr2TcO4 , a 4 d transition-metal layered perovskite of the K2NiF4 type with half-filled t2 g states. The effect of local Coulomb repulsion between the t2 g orbitals is included within the density-functional theory (DFT) + U and DFT + dynamical mean-field theory (DMFT) methods. The DFT + DMFT predicts paramagnetic Sr2TcO4 to be close to the Mott insulator-to-metal transition, similarly to the cubic compound SrTcO3. The intersite exchange interactions computed within the DFT + DMFT framework point to a strong antiferromagnetic coupling between the neighboring Tc sites within the layer. We then evaluate the Néel temperature TN within a classical Monte Carlo approach including dipolar interactions, which stabilize the magnetic order in the frustrated K2NiF4 lattice structure. Our approach is validated by applying it to a set of layered and cubic perovskites, for which we obtain TN in fair agreement with experiment. Within the same approach we obtain the TN of Sr2TcO4 to be about 450 K. We explore also the effect of anisotropy in exchange interactions due to spin-orbit coupling. These lead to a somewhat higher transition temperature, 550 K.

  12. Peer Review Evaluation Process of Marie Curie Actions under EU's Seventh Framework Programme for Research.

    Directory of Open Access Journals (Sweden)

    David G Pina

    Full Text Available We analysed the peer review of grant proposals under Marie Curie Actions, a major EU research funding instrument, which involves two steps: an independent assessment (Individual Evaluation Report, IER performed remotely by 3 raters, and a consensus opinion reached during a meeting by the same raters (Consensus Report, CR. For 24,897 proposals evaluated from 2007 to 2013, the association between average IER and CR scores was very high across different panels, grant calls and years. Median average deviation (AD index, used as a measure of inter-rater agreement, was 5.4 points on a 0-100 scale (interquartile range 3.4-8.3, overall, demonstrating a good general agreement among raters. For proposals where one rater disagreed with the other two raters (n=1424; 5.7%, or where all 3 raters disagreed (n=2075; 8.3%, the average IER and CR scores were still highly associated. Disagreement was more frequent for proposals from Economics/Social Sciences and Humanities panels. Greater disagreement was observed for proposals with lower average IER scores. CR scores for proposals with initial disagreement were also significantly lower. Proposals with a large absolute difference between the average IER and CR scores (≥10 points; n=368, 1.5% generally had lower CR scores. An inter-correlation matrix of individual raters' scores of evaluation criteria of proposals indicated that these scores were, in general, a reflection of raters' overall scores. Our analysis demonstrated a good internal consistency and general high agreement among raters. Consensus meetings appear to be relevant for particular panels and subsets of proposals with large differences among raters' scores.

  13. Peer Review Evaluation Process of Marie Curie Actions under EU's Seventh Framework Programme for Research.

    Science.gov (United States)

    Pina, David G; Hren, Darko; Marušić, Ana

    2015-01-01

    We analysed the peer review of grant proposals under Marie Curie Actions, a major EU research funding instrument, which involves two steps: an independent assessment (Individual Evaluation Report, IER) performed remotely by 3 raters, and a consensus opinion reached during a meeting by the same raters (Consensus Report, CR). For 24,897 proposals evaluated from 2007 to 2013, the association between average IER and CR scores was very high across different panels, grant calls and years. Median average deviation (AD) index, used as a measure of inter-rater agreement, was 5.4 points on a 0-100 scale (interquartile range 3.4-8.3), overall, demonstrating a good general agreement among raters. For proposals where one rater disagreed with the other two raters (n=1424; 5.7%), or where all 3 raters disagreed (n=2075; 8.3%), the average IER and CR scores were still highly associated. Disagreement was more frequent for proposals from Economics/Social Sciences and Humanities panels. Greater disagreement was observed for proposals with lower average IER scores. CR scores for proposals with initial disagreement were also significantly lower. Proposals with a large absolute difference between the average IER and CR scores (≥10 points; n=368, 1.5%) generally had lower CR scores. An inter-correlation matrix of individual raters' scores of evaluation criteria of proposals indicated that these scores were, in general, a reflection of raters' overall scores. Our analysis demonstrated a good internal consistency and general high agreement among raters. Consensus meetings appear to be relevant for particular panels and subsets of proposals with large differences among raters' scores.

  14. GLANAM (Glaciated North Atlantic Margins): A Marie Curie Initial Training Network between Norway, the UK & Denmark

    Science.gov (United States)

    Petter Sejrup, Hans; Oline Hjelstuen, Berit

    2015-04-01

    GLANAM (Glaciated North Atlantic Margins) is an Initial Training Network (ITN) funded under the EU Marie Curie Programme. It comprises 10 research partners from Norway, UK and Denmark, including 7 University research teams, 1 industrial full partner and 2 industrial associate partners. The GLANAM network will employ and train 15 early career researchers (Fellows). The aim of GLANAM is to improve the career prospects and development of young researchers in both the public and private sector within the field of earth science, focusing on North Atlantic glaciated margins. The young scientists will perform multi-disciplinary research and receive training in geophysics, remote sensing, GIS, sedimentology, geomorphology, stratigraphy, geochemistry and numerical modeling through three interconnected work packages that collectively address knowledge gaps related to the large, glacial age, sedimentary depocentres on the North Atlantic margin. The 15 Fellows will work on projects that geographically extend from Ireland in the south to the High Arctic. Filling these gaps will not only result in major new insights regarding glacial age processes on continental margins in general, but will also provide paleoclimate information essential for understanding the role of marine-based ice sheets in the climate system and for the testing of climate models. GLANAM brings together leading European research groups working on glaciated margins in a coordinated and collaborative research and training project. Focusing on the North Atlantic margins, this coordinated approach will lead to a major advance in the understanding of glaciated margins more widely and will fundamentally strengthen European research and build capacity in this field.

  15. The 1951-98 experience of the Paris Institut Curie Radiopathology Unit: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Cosset, J.M.; Perdereau, B.; Dubray, B.; Helfre, S.; Brixy, F.; Gongora, R.; Fourquet, A. [Institut Curie, 26 rue d' Ulm, 75005 Paris (France)

    1999-12-01

    From 1 January 1951 to 30 June 1998, 696 patients presented spontaneously or were referred to the French Institut Curie Radiopathology Unit following a more or less severe accidental irradiation. Of these, 568 patients came from France, while 128 were sent by various foreign countries. The very great majority of irradiation accidents occurred in the workplace, particularly in industry. Interestingly, 'non-nuclear' industry was responsible for three times more events than the nuclear industry. While incidental irradiation of the public by lost radioactive sources was exceedingly rare in France, it seemed to be more frequent in our cohort of foreign patients. Radiation phobia accounted for about 10% of cases in the French cohort, but the number of cases did not seem to increase with time. Overall, the accrual of patients over time appears to be stable, with 10 to 25 new cases consulting each year. Fortunately, a majority of cases corresponded to low-level irradiation (and even no irradiation at all). In the French cohort, only 21.6% of patients, showing deterministic effects, required some form of treatment, with 4.9% considered as 'severe' cases. Not unexpectedly, more patients required treatment in the foreign cohort (35.2%), with 24.2% of severe cases, including four deaths. The main features of this database are consistent with the data previously reported by the IAEA, UNSCEAR and REAC/TS. Although the number of severe cases is small, it should still be considered to be too high, especially as most of these accidents could have been easily avoided if a few basic radioprotection rules had been fully respected. (abstract)

  16. Curie point depth in the SW Caribbean using the radially averaged spectra of magnetic anomalies

    Science.gov (United States)

    Salazar, Juan M.; Vargas, Carlos A.; Leon, Hermann

    2017-01-01

    We have estimated the Curie Point Depth (CPD) using the average radial power spectrum in a tectonically complex area located in the SW Caribbean basin. Data analyzed came from the World Digital Magnetic Anomaly Map, and three methods have been used to compare results and evaluate uncertainties: Centroid, Spectral Peak, and Forward Modeling. Results show a match along the three methods, suggesting that the CPD values in the area ranging between 6 km and 50 km. The results share the following characteristics: A) High values (> 30 km) are in continental regions; B) There is a trend of maximum CPD values along the SW-NE direction, starting from the Central Cordillera in Colombia to the Maracaibo Lake in Venezuela; C) There is a maximum CPD at the Sierra Nevada de Santa Marta (Colombia) as well as between Costa Rica - Nicaragua and Nicaragua - Honduras borders. The lowest CPD values (coastal regions and offshore. We also tested results by estimating the geothermal gradient and comparing measured observations of the study area. Our results suggest at least five thermal terrains in the SW Caribbean Basin: A) The area that is comprising the Venezuela Basin, the Beata Ridge and the Colombia Basin up to longitude parallel to the Providencia Throat. B) The area that includes zones to the north of the Cocos Ridge and Panam Basin up to the trench. C) The orogenic region of the northern Andes and including areas of the Santa Marta Massif. D) The continental sector that encompasses Nicaragua, northern Costa Rica and eastern of Honduras. E) Corresponds to areas of the northern Venezuela and Colombia, NW of Colombia, the Panamanian territory and the transition zones between the Upper and Lower Nicaragua Rise.

  17. Normal-state anomalies in the transport and magnetic properties in the (La1-xPrx)1.85Sr0.15CuO4 system and their correlation with Tc suppression: A signature of the effects of orthorhombic distortions

    Science.gov (United States)

    Musa, J. E.; García, S.; Rothier de Amaral, M., Jr.; Salim de Amorim, H.; Giordanengo, B.; Baggio-Saitovitch, E. M.; Pagliuso, P. J. G.; Rettori, C.; Yelon, W. B.; Malik, S. K.

    1999-03-01

    The correlation between the normal-state anomalies observed in the magnetic and transport properties of the (La1-xPrx)1.85Sr0.15CuO4 system with 0<=x<=0.5 was studied. The x-ray-diffraction patterns revealed a linear increase of the (a-b) orthorhombic parameter with the Pr content. The resistivity curves showed an increasing deviation from linearity below ~100 K. This anomaly was properly accounted by a logarithmic term, whose coefficient C linearly increases with x. Superconducting quantum interference device measurements of the normal-state magnetic susceptibility evidenced a deviation from the Pr3+ Curie-Weiss behavior in the same temperature range for which the resistivity anomaly occurs. This behavior is explained in terms of an induced magnetic moment at the CuO2 layers under strain. A Dzialoshinsky-Moriya interaction, associated to the orthorhombic distortions, is proposed to be the source of a weak canted ferromagnetic component, which develops in conjunction with an enhancement of the antiferromagnetic correlations. A comprehensive picture of the conduction mechanism for the whole system is presented in terms of a Kondo-like scattering of the mobile holes by the spin fluctuations at the conduction planes. Tc suppression was found to correlate with C, suggesting that the excitation which interacts with the carriers in the normal state is relevant for superconductivity.

  18. Low noise high-Tc superconducting bolometers on silicon nitride membranes for far-infrared detection

    NARCIS (Netherlands)

    Nivelle, de M.J.M.E.; Bruijn, M.P.; Vries, de R.; Wijnbergen, J.J.; Korte, de P.A.J.; Sanchez, S.; Elwenspoek, M.; Heidenblut, T.; Schwierzi, B.; Michalke, W.; Steinbeiss, E.

    1997-01-01

    High-Tc GdBa2Cu3O7 – delta superconductor bolometers with operation temperatures near 89 K, large receiving areas of 0.95 mm2 and very high detectivity have been made. The bolometers are supported by 0.62 µm thick silicon nitride membranes. A specially developed silicon-on-nitride layer was used to

  19. What makes the Tc of FeSe/SrTiO3 so high?

    Institute of Scientific and Technical Information of China (English)

    Dung-Hai Lee

    2015-01-01

    This paper reviews some of the recent progresses in the study of high temperature superconductivity in the interface between a single unit cell FeSe and SrTiO3. It offers the author’s personal view of why Tc is high and how to further increase it.

  20. General report of TC 106: Unsaturated soils

    NARCIS (Netherlands)

    Jommi, C.

    2013-01-01

    This general report summarises the contributions on unsaturated soil mechanics submitted to the Discussion Session of TC106 – Unsaturated soils –at the 18th International Conference on Soil Mechanics and Geotechnical Engineering held in Paris in September 2013. The thirty-five papers collected under

  1. General report of TC 106: Unsaturated soils

    NARCIS (Netherlands)

    Jommi, C.

    2013-01-01

    This general report summarises the contributions on unsaturated soil mechanics submitted to the Discussion Session of TC106 – Unsaturated soils –at the 18th International Conference on Soil Mechanics and Geotechnical Engineering held in Paris in September 2013. The thirty-five papers collected under

  2. Grain boundaries in high-Tc superconductors

    NARCIS (Netherlands)

    Hilgenkamp, H.; Mannhart, J.

    2002-01-01

    Since the first days of high-Tc superconductivity, the materials science and the physics of grain boundaries in superconducting compounds have developed into fascinating fields of research. Unique electronic properties, different from those of the grain boundaries in conventional metallic supercondu

  3. Contrastive analysis of three dynamic constitutive models for TC4 titanium alloy%TC4钛合金三种动态本构模型的对比分析

    Institute of Scientific and Technical Information of China (English)

    胡绪腾; 宋迎东

    2013-01-01

    Material parameters in Johnson-Cook model, modified Zerilli - Armstrong and Bammann viscoplasticity model were estimated by least - squares optimization method based on uniaxial deformation data of TC4 under quasi - static and dynamic loading. The ability of three constitutive models to model the strain rate and temperature dependent deformation behavior of TC4 was evaluated. The result indicates that Bammann model correlates TC4 test data best. Johnson-Cook model and modified Zerilli-Armstrong model have similar correlation and prediction ability to TC4 test data, but they cannot describe the strain rate sensitivity under dynamic loading at room temperature well.%基于TC4合金的应变率和温度相关单轴应力-应变曲线试验数据,优化估计了Johnson-Cook、修正Zerilli-Armstrong和Bammann黏塑性三种动态本构模型的材料参数,对比分析了三种本构模型对TC4单轴变形试验数据的描述能力.结果表明:在TC4变形试验参数范围内,Bammann黏塑性模型可以较好地描述TC4合金的应变率和温度相关变形行为;Johnson-Cook模型和修正Zerilli-Armstrong模型的单轴应力-应变曲线计算结果比较接近,但与试验数据的相关性相对较差,均不能如实反映TC4室温动态压缩试验的应变率敏感性.

  4. Structure and magnetism in S r1 -xAxTc O3 perovskites: Importance of the A -site cation

    Science.gov (United States)

    Reynolds, Emily; Avdeev, Maxim; Thorogood, Gordon J.; Poineau, Frederic; Czerwinski, Kenneth R.; Kimpton, Justin A.; Yu, Michelle; Kayser, Paula; Kennedy, Brendan J.

    2017-02-01

    The S r1 -xB axTc O3 (x =0 , 0.1, 0.2) oxides were prepared and their solid-state and magnetic structure studied as a function of temperature by x-ray and neutron powder diffraction. The refined Tc moments at room temperature and Néel temperatures for B a0.1S r0.9Tc O3 and B a0.2S r0.8Tc O3 were 2.32 (14 ) μβ and 2.11 (13 ) μβ and 714 ∘C and 702 ∘C , respectively. In contrast to expectations, the Néel temperature in the series S r1 -xAxTc O3 decreases with increasing Ba content. This observation is consistent with previous experimental measurements for the two series A M O3 (M =Ru , Mn; A =Ca , Sr, Ba) where the maximum magnetic ordering temperature was observed for A =Sr . Taken with these previous results the current work demonstrates the critical role of the A -site cation in the broadening of the π* bandwidth and ultimately the magnetic ordering temperature.

  5. TC81201F MPEG2 decoder LSI; MPEG2 decoder LSI TC81201F

    Energy Technology Data Exchange (ETDEWEB)

    Kitagaki, K. [Toshiba Corp., Tokyo (Japan)

    1996-04-01

    The moving picture expert group 2 (MPEG2) decoder LSI series have been developed, in order to meet needs for diversifying multi-media systems. MPEG2 is an international standard for coding moving pictures, capable of compressing large quantities of moving picture data. Therefore, the decoder LSI for the MPEG2 signals is also a key device to realize the multi-media systems. The system needs are diversifying, as seen in different audio codes for DVD`s and digital satellite broadcasting systems (DBS`s). The company has developed, based on decoder LSI T9556 announced in 1994, TC81200F for mass production, TC81201F optimized for the DVD system and TC81211F as the one-chip device for MPEG1 decoder. Chip cost and system cost of TC81201F are reduced by optimizing functions and circuits, and by reducing external memories. 4 refs., 4 figs., 1 tab.

  6. First-principles prediction of the equation of state for TcC with rocksalt structure

    Science.gov (United States)

    Sun, Xiao-Wei; Chu, Yan-Dong; Liu, Zi-Jiang; Song, Ting; Tian, Jun-Hong; Wei, Xiao-Ping

    2014-10-01

    The equation of state of TcC with rocksalt structure is investigated by means of first-principles density functional theory calculations combined with the quasi-harmonic Debye model in which the phononic effects are considered. Particular attention is paid to the predictions of the compressibility, the isothermal bulk modulus and its first pressure derivative which play a central role in the formulation of approximate equations of state for the first time. The properties of TcC with rocksalt structure are summarized in the pressure range of 0-80 GPa and the temperature up to 2500 K.

  7. The influence of anharmonic phonons on the isotope effect in high-{Tc} oxides

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H.; Cohen, M.L.

    1992-01-01

    Anharmonic phonons are examined to study the unusual isotope effect exponents for the high-{Tc} oxides. Within a simple model of anharmonicity, the mass dependences of the electron-phonon coupling constant {lambda} and the phonon frequency determine the isotope effect exponent {alpha} as a function of coupling strength. A model in which the outer wells of a multiple-well potential deepen as the orthorhombic/low temperature tetragonal phase transition in La{sub 2-x}M{sub x}CuO{sub 4} is approached is consistent with some experimentally observed variations in {Tc} and {alpha}. 10 refs.

  8. The influence of anharmonic phonons on the isotope effect in high- Tc oxides

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H.; Cohen, M.L.

    1992-01-01

    Anharmonic phonons are examined to study the unusual isotope effect exponents for the high-{Tc} oxides. Within a simple model of anharmonicity, the mass dependences of the electron-phonon coupling constant {lambda} and the phonon frequency determine the isotope effect exponent {alpha} as a function of coupling strength. A model in which the outer wells of a multiple-well potential deepen as the orthorhombic/low temperature tetragonal phase transition in La{sub 2-x}M{sub x}CuO{sub 4} is approached is consistent with some experimentally observed variations in {Tc} and {alpha}. 10 refs.

  9. Th1 Th2, Tc1 Tc2 cells of patients with otolaryngological diseases

    Directory of Open Access Journals (Sweden)

    Nobuo Ohta

    2004-01-01

    Full Text Available Cytokines are important regulatory mediators secreted by T cells and other immunoactive cells. Based on the cytokine synthesis patterns, CD4 T cells can often be classified into at least two populations with different immune regulatory functions. The Th1 cells, producing interleukin (IL-2 and interferon (IFN-γ, are often associated with cell-mediated immune responses such as delayed type hypersensitivity (DTH, whereas Th2 cells, secreting IL-4, IL-5 and IL-13, usually provide B cell help and enhance allergic reactions. Naïve CD8 T cells, similar to CD4 T cells, can differentiate into at least two subsets of cytolytic effector cells with distinct cytokine patterns. The Tc1 cells secrete a Th 1 - like cytokine pattern, including IL-2 and IFN-γ. The Tc2 cells produce Th2 cytokines, including IL-4, IL-5 and 11—10. There is increasing evidence that Th1/Th2 and Tc1/Tc2 cytokine imbalance has been of patho- genetic importance in various diseases, such as allergic and autoimmune diseases. The present review article focuses on the evidence that the imbalance of Th1/Th2 and Tc1/Tc2 cytokines plays an important role in various otolaryngological diseases, such as Kimura's disease, Wegener's granulomatosism, acute perceptive hearing loss and Meniere's disease. It is concluded that the predominance of Th 1 or Th2 and Tc1 or Tc2 cells may contribute to the mechanism in the pathogenesis of these otolaryngological diseases.

  10. Enhanced microwave absorption near Tc in micron-size powders of cuprate superconductors. [YBaCuO; BiSrCaCuO; YBaZnCuO; BiPbSbScCaCuO

    Energy Technology Data Exchange (ETDEWEB)

    Manheimer, M.A.; Lofland, S. (Lab. for Physical Sciences, College Park, MD (United States)); Gould, A.; Bhagat, S.M.; Halsey, B.; Green, S.M. (Dept. of Physics and Center for Superconductivity Research, Univ. of Maryland, College Park (United States)); Tyagi, S. (Dept. of Physics and Atmospheric Science, Drexel Univ., Philadelphia, PA (United States))

    1991-11-20

    We report a systematic study of a large peak in the microwave losses near Tc in micron-size powders of high-Tc superconducting cuprates. It is demonstrated that the effect arises because all the grains do not have a single Tc. The onset of superconductivity in some particles enhances the RF field 'seen' by their neighbors leading to a net increase in absorption. The temperature regime of enhanced loss spans the extrema of the transition temperatures. (orig.).

  11. Tc Generator Development: Up-to-Date Tc Recovery Technologies for Increasing the Effectiveness of Mo Utilisation

    Directory of Open Access Journals (Sweden)

    Van So Le

    2014-01-01

    Full Text Available A review on the Mo sources available today and on the Tc generators developed up to date for increasing the effectiveness of Mo utilisation is performed in the format of detailed description of the features and technical performance of the technological groups of the Mo production and Tc recovery. The latest results of the endeavour in this field are also surveyed in regard of the technical solution for overcoming the shortage of Mo supply. The technological topics are grouped and discussed in a way to reflect the similarity in the technological process of each group. The following groups are included in this review which are high specific activity Mo: the current issues of production, the efforts of more effective utilisation, and the high specific activity Mo-based Tc generator and Tc concentration units; low specific activity Mo: the Mo production based on neutron capture and accelerators and the direct production of Tc and the methods of increasing the specific activity of Mo using Szilard-Chalmers reaction and high electric power isotopic separator; up-to-date technologies of Tc recovery from low specific activity Mo: the solvent extraction-based Tc generator, the sublimation methods for Mo/Tc separation, the electrochemical method for Tc recovery, and the column chromatographic methods for Tc recovery. Besides the traditional Tc-generator systems, the integrated Tc generator systems (Tc generator column combined with postelution purification/concentration unit are discussed with the format of process diagram and picture of real generator systems. These systems are the technetium selective sorbent column-based generators, the high Mo-loading capacity column-based integrated Tc generator systems which include the saline-eluted generator systems, and the nonsaline aqueous and organic solvent eluent-eluted generator systems using high Mo-loading capacity molybdategel and recently developed sorbent columns. Tc concentration methods used in the

  12. 99mTc-YIGSR as a Receptor Tracer in Imaging the Ehrlich Ascites Tumor-bearing Mice as Compared with 99mTc-MIBI

    Institute of Scientific and Technical Information of China (English)

    HU Jia; QIN Guangming; ZHANG Yongxue; AN Rui; LAN Xiaoli

    2007-01-01

    The validity of 99mTc-YIGSR, a novel receptor radio-tracer, in imaging the Ehrlich ascites tumor was evaluated. YIGSR, a pentapeptide of laminin, was labeled with 99mTc by using a bifunctional chelator S-Acetly-NH3-MAG3. The MIBI was labeled with 99mTc by following the kit instruction. The mice of tumor group were intravenously injected 1-2 mCi of 99mTc-YIGSR or 99mTc-MIBI via caudal vein, immobilized and imaged under a Gamma camera. The same procedure was performed in mice of blockade group, in which the unlabeled YIGSR was previously injected to block the receptor-recognition sites, and inflammation group serving as control. The reverse-phase Sep-Pak C18 chromatogram was found to have an essentially complete conjugation between YIGSR and S-Acetly-NH3-MAG3. The conjugated YIGSR could be radio-labeled successfully with 99mTc at room temperature and neutral pH, with a radio-labeling yield of 62%. Without the chelator S-Acetly-NH3-MAG3, the YIGSR was labeled with 99mTc at an efficiency of 4%. The imagological study revealed obvious tumor accumulation of 99mTc-YIGSR 15 min after the injection, and the uptake peaked after 3 h with a tumor-to-muscle ratio (T/M) of 11.36. The radio-tracer was slowly cleared up and resulted in a T/M of 3.01 at the 8th h after the injection. As for blocked group, the tumor uptake of radiotracer was significantly lower, with the highest T/M being 4.61 after 3 h and 0.89 after 8 h. The T/M was 3.72 at the 3rd h and 1.29 at the 8th h after the 99mTc-YIGSR injection in the inflammatory group. The T/M was significantly higher in tumor group than in inflammatory group or control group (P<0.001). In the 99mTc-MIBI group, the T/M was 1.40 at the 3rd h and 0.55 at the 8th h after the injection, which showed a significant difference as compared with 99mTc-YIGSR (P<0.001).It is concluded that YIGSR can be successfully radiolabelled by using S-Acetly-NH3-MAG3.99mTc-YIGSR has many advantages in tumor imaging, such as quick and clear visualization

  13. TC-Investigator: A Matlab Program to Explore Pseudosections

    Science.gov (United States)

    Pearce, Mark; Gazley, Michael; White, Alistair

    2014-05-01

    Forward modelling of bulk rock compositions to constrain pressures and temperatures of metamorphism based on mineral assemblage is a commonly used technique. The pseudosections produced contain a wealth of information about predicted mineral compositions and abundances that goes far beyond variations in mineral assemblage. A grid of these variations can be contoured using Gibbs free energy minimisation software (such as Theriak-Domino) or precise isopleths calculated for specific quantities in THERMOCALC. We have produced a new piece of software called TC-Investigator that amalgamates these approaches to provide a relatively quick and user friendly way to contour all compositional parameters and mineral modes across a THERMOCALC pseudosection. TC-Investigator takes the postscript pseudosection diagram and creates a grid of points at a user-specified resolution. THERMOCALC is then used to calculate the equilibrium mineral assemblage at each point using an initial starting guess provided by the user (this can be calculated during initial pseudosection calculation). Once all points have been tried, any that failed to calculate are re-tried using interpolated starting guess values from the surrounding points. This procedure is iterated until no more solutions are found. Any remaining unsolved points are then interpolated numerically from surrounding solutions to produce a fully quantified set of mineral modes and compositions. Following calculation, the dataset can be contoured and output as figures, output as a Matlab readable binary structure or selected compositions written to an ASCII text file. Compositional maps created by TC-Investigator have the power to inform the user about compositional variables that are not conventionally considered. The automated calculation method makes it easy to investigate all variables in one go. For example, in metapelitic rocks, garnet shows the variations in composition that are usually contoured, however, these couple to

  14. Power Systems Development Facility Gasification Test Run TC10

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2002-12-30

    This report discusses Test Campaign TC10 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier during TC10 in air- (mainly for transitions and problematic operations) and oxygen-blown mode. Test Run TC10 was started on November 16, 2002, and completed on December 18, 2002. During oxygen-blown operations, gasifier temperatures varied between 1,675 and 1,825 F at pressures from 150 to 180 psig. After initial adjustments were made to reduce the feed rate, operations with the new fluidized coal feeder were stable with about half of the total coalfeed rate through the new feeder. However, the new fluidized-bed coal feeder proved to be difficult to control at low feed rates. Later the coal mills and original coal feeder experienced difficulties due to a high moisture content in the coal from heavy rains. Additional operational difficulties were experienced when several of the pressure sensing taps in the gasifier plugged. As the run progressed, modifications to the mills (to address processing the wet coal) resulted in a much larger feed size. This eventually resulted in the accumulation of large particles in the circulating solids causing operational instabilities in the standpipe and loop seal. Despite problems with the coal mills, coal feeder, pressure tap nozzles and the standpipe, the gasifier did experience short periods of stability during oxygenblown operations. During these periods, the syngas quality was high. During TC10, the gasifier gasified over 609 tons of Powder River Basin subbituminous coal and

  15. Power Systems Development Facility Gasification Test Run TC11

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2003-04-30

    This report discusses Test Campaign TC11 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). Test run TC11 began on April 7, 2003, with startup of the main air compressor and the lighting of the gasifier start-up burner. The Transport Gasifier operated until April 18, 2003, when a gasifier upset forced the termination of the test run. Over the course of the entire test run, gasifier temperatures varied between 1,650 and 1,800 F at pressures from 160 to 200 psig during air-blown operations and around 135 psig during enriched-air operations. Due to a restriction in the oxygen-fed lower mixing zone (LMZ), the majority of the test run featured air-blown operations.

  16. Doping-Induced Change of Optical Properties in Underdoped High-Tc Superconductors.

    Science.gov (United States)

    Liu, H. L.; Tanner, D. B.; Berger, H.; Forro, L.; Margaritondo, G.

    1997-03-01

    We report on ab-plane reflectivity measurements in underdoped single crystals of Bi_2Sr_2CaCu_2O_8. A generalized Drude analysis of the optical conductivity shows that the frequency-dependent scattering rate, 1/τ(ω,T), of two moderately underdoped samples (with Tc = 85, 80 K) displays similar structure at low frequencies as temperature is reduced. This threshold structure in the scattering rate is enhanced and moves to higher frequencies over the whole temperature range in two heavily underdoped crystals (with Tc = 40, 35 K). Alternatively, a two-component description has been used to fit the optical data. The Drude relaxation rate 1/τ(T) varies linearly with temperature and decreases dramatically below Tc in all underdoped materials. Interestingly, the magnitude of both elastic scattering and inelastic scattering of Ni doped crystal is large compared to other samples. We also found that superconducting Tc scales linearly with the condensated superfluid density, consistent with the results of muon-spin-rotation experiments. supported by NSF-9403894

  17. Radiolabelling of human platelets with sup 99m Tc-HMPAO

    Energy Technology Data Exchange (ETDEWEB)

    Vorne, M.; Honkanen, T.; Karppinen, K.; Roening, M.; Sakki, S. (Paeijaet-Haeme Central Hospital, Lahti (Finland))

    1989-01-01

    The optimum conditions for labelling platelets with lipophilic {sup 99m}Tc-hexamethyl propylene amine oxime ({sup 99m}Tc-HMPAO) were evaluated. An aseptic closed system was used throughout the procedure in patient studies. 48 ml blood were withdrawn into 12 ml ACD using sterile 60 ml plastic syringes. After mixing, the blood was transferred to sterile 10 ml vacuum tubes and platelets were isolated according to standard centrifugation procedures. The labelling efficiency was not dependent upon incubation temperature (22 deg. C, 37 deg. C) but was greater in saline than in the presence of plasma. The labelling efficiency increased with time up to 60 min in saline. The elution of {sup 99m}Tc from platelets was about 25% in plasma milieu in vitro but did not increase with time during 160 min. 5 patients with verified fresh deep vein thrombosis in the lower leg were imaged after injection of labelled autologous platelets. All 4 of the patients without anticoagulant therapy showed positive uptake of {sup 99m}Tc-HMPAO-labelled platelets, but the 5th patient - under heparin therapy - was negative in scientigraphy. Our results are encouraging and {sup 99m}Tc-HMPAO-labelled platelets offer a promising tool for evaluating various clinical situations. (author).

  18. 10. national conference of Maria Sklodowska-Curie Polish Radiation Research Society. Abstract of papers; 10. krajowy zjazd Polskiego Towarzystwa Badan Radiacyjnych im. Marii Sklodowskiej-Curie. Streszczenia referatow

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The 10. national conference of M. Sklodowska-Curie Polish Radiation Research Society has given the opportunity to present novel Polish advisement in all fields of radiation research, e.g. radiation chemistry and biology, radiation processing, environmental study, mathematical modeling and simulation as well as different theoretical study. As a whole it may be treated as a review of actual state of art. The scientific progress since 1992 when the 9. national conference place up to now can be easy assessed on the base of presented material.

  19. Tc Chemistry in HLW: Role of Organic Complexants

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Nancy S.; Conradsen, Steven D.

    2003-06-01

    Tc complexation with organic compounds in tank waste plays a significant role in the redox chemistry of Tc and the partitioning of Tc between the supernatant and sludge components in waste tanks. These processes need to be understood so that strategies to effectively remove Tc from high-level nuclear waste prior to waste immobilization can be developed and so that long-term consequences of Tc remaining in residual waste after sludge removal can be evaluated. Only limited data on the stability of Tc-organic complexes exists and even less thermodynamic data on which to develop predictive models of Tc chemical behavior is available. To meet these challenges we are conducting a research program to study to develop thermodynamic data on Tc-organic complexation over a wide range of chemical conditions. We will attempt to characterize Tc-speciation in actual tank waste using state-of-the-art analytical organic chemistry, separations, and speciation techniques to validate our model. On the basis of such studies we will develop credible model of Tc chemistry in HLW that will allow prediction of Tc speciation in tank waste and Tc behavior during waste pretreatment processing and in waste tank residuals.

  20. Mismatched uptake of Tc-99m-ECD and Tc-99m-HMPAO in subacute cerebral infarction: Tc-99m-ECD for viability and Tc-99m-HMPAO for flow restoration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D. S.; Hyun, I. Y.; Kim, S. K. [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)] [and others

    1997-07-01

    Tc-99m-HMPAO reflects tissue perfusion but Tc-99m-ECD uptake is affected by tissue viability in addition to tissue perfusion which the varied state of cellular retention of Tc-99m-ECD reflects. Luxuriously perfused area on Tc-99m-HMPAO SPECT implies that this cortex was already reperfused either spontaneously or after thrombolysis and that accompanied paralysis of vascular reactivity in those zones warms progressive deterioration. We tried to find out if we can use sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT to reveal cortical perfusion and severity and range of risky areas of cerbral cortex despite reperfusion in sub-acute infarction. In 13 patients (M ; F =7 : 6, mean age 57 (range: 26-84)) with cortical (n=12) and basal ganglia infarction (1), we performed sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT at the same position. At first, 555 MBq of Tc-99m-ECD was injected and imaged and then 1110 MBq of Tc-99m-HMPAO was injected again and imaged with the patients in situ, and the first image (Tc-99m-ECD) and the subtracted image (2nd- 1st : Tc-99m-HMPAO) were compared slice by slice. Study was done from 3 days to 31 days (16{+-}9) after ictus. Tc-99m-ECD uptake was always less than or equal to Tc-99m-HMPAO uptake at the lesion in all cases. Luxury perfusion was prominent in four patients. Mismatched uptake was found in 10 patients. Severity of mismatch showed diverse spectrum and was ranged from total middle cerebral artery territory (1 case) to peripheral thin zones around infarction (2 cases). The other 7 showed intermediate amount of tissues with mismatch , i.e., Tc-99m-ECD defects where Tc-99m-HMPAO uptake is in part increased, normal or decreased. Upon discharge, patients having more uptake with Tc-99m-ECD predicted improvement. Patients having mismatched uptake went dichotomous way. In conclusion, Tc-99m-ECD/Tc-99m-HMPAO sequential SPECT is feasible and reveal both tissue perfusion (Tc-99m-HMPAO ) and discrepant Tc-99m-ECD uptake probably reflecting viability in acute

  1. PREFACE: 2013 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium: Measurement Across Physical and Behavioural Sciences

    Science.gov (United States)

    Battista Rossi, Giovanni; Crenna, Francesco; Belotti, Vittorio

    2013-09-01

    The 2013 Joint IMEKO (International Measurement Confederation) TC1-C7-TC13 was organised by the University of Genova - DIME/MEC, Measurement Laboratory, Italy, on 4-6 September 2013. The work of this symposium is reported in this volume. The scope of the symposium includes the main topics covered by the above Technical Committees: TC1 Education and Training in Measurement and Instrumentation TC7 Measurement Science TC13 Measurements in Biology and Medicine This is in keeping with the tradition set by the previous events of this well established series. There has been a special focus on measurement across physical and behavioural sciences, with the aim of highlighting the interdisciplinary character of measurement science and of promoting constructive interactions with scientists in other disciplines. The discussion was introduced by keynote lectures on measurement challenges in psychophysics, psychometrics and quantum physics. The symposium was attended by experts working in these areas from 18 countries, including USA, Australia and Japan, and provided a useful forum for them to share and exchange their work and ideas. In total over sixty papers are included in the volume, organised according to the presentation sessions. Each paper was independently peer-reviewed by two reviewers from a distinguished international panel. The Symposium was held in Genova, which was the European Capital of Culture in 2004, and took place in Palazzo Ducale, an important historical building whose construction started in the 13th century, and that has been the house of the Duke of Genova from the 14th century. Genova, whose name comes from the Latin word 'Janua' (meaning 'door', as January is the door month of the year), has been regarded over the centuries as a door connecting Europe with the different countries and cultures of the Mediterranean basin and thus was an appropriate site for an international symposium involving different and new scientific visions and approaches to

  2. Shock compaction of high- Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Weir, S.T.; Nellis, W.J.; McCandless, P.C.; Brocious, W.F. (Lawrence Livermore National Lab., CA (USA)); Seaman, C.L.; Early, E.A.; Maple, M.B. (California Univ., San Diego, La Jolla, CA (USA). Dept. of Physics); Kramer, M.J. (Ames Lab., IA (USA)); Syono, Y.; Kikuchi, M. (Tohoku Univ., Sendai (Japan))

    1990-09-01

    We present the results of shock compaction experiments on high-{Tc} superconductors and describe the way in which shock consolidation addresses critical problems concerning the fabrication of high J{sub c} bulk superconductors. In particular, shock compaction experiments on YBa{sub 2}Cu{sub 3}O{sub 7} show that shock-induced defects can greatly increase intragranular critical current densities. The fabrication of crystallographically aligned Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} samples by shock-compaction is also described. These experiments demonstrate the potential of the shock consolidation method as a means for fabricating bulk high-{Tc} superconductors having high critical current densities.

  3. New superconductors from granular to high T$_{c}$

    CERN Document Server

    Deutscher, Guy

    2017-01-01

    How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This interesting book aims to provide some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a short coherence length, a small superfluid density and an inhomogeneous structure.

  4. International Discussion Meeting on High-Tc Superconductors

    CERN Document Server

    1988-01-01

    In the past two years conferences on superconductivity have been characterized by the attendance of hundreds of scientists. Consequently, the organizers were forced to schedule numerous parallel sessions and poster presentations with an almost unsurveyable amount of information. It was, therefore, felt that a more informal get-together, providing ample time for a thourough discussion of some topics of current interest in high-temperature superconductivity, was timely and benefitial for leading scientists as well as for newcomers in the field. The present volume contains the majority of papers presented at the International Discussion Meeting on High-Tc Superconductors held at the Mauterndorf Castle in the Austrian Alps from February 7 to 11, 1988. Each subject was introduced in review form by a few invited speakers and then discussed together with the contributed poster presentations. These discussion sessions chaired by selected scientists turned out to be the highlights of the meeting, not only because all ...

  5. Deformation processing of high-Tc superconducting oxides

    Science.gov (United States)

    Rajan, K.; German, R. M.; Knorr, D. B.; Maccrone, R. K.; Misiolek, W.; Wright, R. N.

    1989-04-01

    Plastic deformation and texture development in polycrystalline YBa2Cu3O7- δ has been studied to expedite the process development of high-critical-temperature (high-Tc) superconducting wires and tapes. It is anticipated that deformation texture will be a major processing consideration in terms of maximizing critical current density, assessing conductor-fabrication options in light of critical current density, and developing such mechanical properties as strength, toughness and thermal fatigue. The intrinsic texture development in YBa2Cu3O7- δ deformation processing should be highly beneficial, insofar as the c axes of the crystals tend to become oriented along the compression axis. This means that conducting tapes and wires formed by rolling, extrusion and drawing can develop textures with the c axis in the transverse or radial direction, thus maximizing the flow of current along the length of the conductor.

  6. Transport coefficients of heavy quarks around $T_c$ at finite quark chemical potential

    CERN Document Server

    Berrehrah, H; Aichelin, J; Cassing, W; Torres-Rincon, J M; Bratkovskaya, E

    2014-01-01

    The interactions of heavy quarks with the partonic environment at finite temperature $T$ and finite quark chemical potential $\\mu_q$ are investigated in terms of transport coefficients within the Dynamical Quasi-Particle model (DQPM) designed to reproduce the lattice-QCD results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature $T_c$. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around $T_c$, at $\\mu_q=0$ as well as at finite $\\mu_q$. Close and above $T_c$ its absolute value matches the lQCD calculations for $\\mu_q=0$. The smooth transition of the heavy quark transport coefficients from the hadronic to the partonic medium corresponds to a cross over in line with lattice calculations, and differs substantially from perturbative QCD (pQCD) calculations which show a large discontinuity at $T_c$. This indicates that in the vicini...

  7. Cyclotron Production of (99m)Tc using (100)Mo2C targets.

    Science.gov (United States)

    Richards, Vernal N; Mebrahtu, Efrem; Lapi, Suzanne E

    2013-10-01

    An investigative study of the (100)Mo (p,2n)(99m)Tc reaction on a medical cyclotron using (100)Mo2C is reported. This is the first report of this compound being used as a target for this reaction. (100)Mo2C, a refractory carbide with high thermal conductivity, properties which underscore its use on a cyclotron, was synthesized using (100)MoO3. Its ease of oxidation back to (100)MoO3 under air at elevated temperatures facilitates the use of thermo-chromatography, a high temperature gas phase separation technique for the separation and isolation of (99m)Tc. Activity yields for (99m)Tc averaged 84% of the calculated theoretical yields. Additionally, the percent recovery of MoO3, the precursor for Mo2C, was consistently high at 85% ensuring a good life cycle for this target material. The produced (99m)Tc was radio-chemically pure and easily labeled MDP for imaging purposes.

  8. Curie point depth and heat flow from spectral analysis of aeromagnetic data over the northern part of Western Desert, Egypt

    Science.gov (United States)

    Saada, Saada Ahmed

    2016-11-01

    The present work aims to estimate the Curie point depth and the surface heat flow for the northern part of the Western Desert using aeromagnetic data. Applying spectral analysis to aeromagnetic anomalies has provided equitable promising geological results, useful for further geothermal or petroleum exploration. The total intensity aeromagnetic map was first reduced to the north magnetic pole to correct the shape and position of different magnetic anomalies over their causative bodies. Secondly, the short wavelengths were removed to enhance the deeper long wavelengths related to the deep sources. Spectral analysis indicates that the area is underlined by an average Curie point depth of about 27 km. This implies an average thermal heat flow (53 mW/m2) lower than the average global heat flow. The investigated area was divided into eighteen blocks, where the average depths to centroid and top of the magnetic source were estimated for each block. The results of this work show a general depth increase of the magnetic boundaries from 24.5 km in the southern area to 33 km at the northern part. The calculated surface heat flow decreases from about 56 to 42 mW/m2 in the same direction. Consequently, this area is characterized by its low geothermal gradient and surface heat flow. This low geothermal gradient indicates that the upper mantle contributes to the magnetic features at the northern offshore parts. This work also recommends by deep drilling for petroleum exploration and production within the Egyptian Mediterranean Sea exploration strip.

  9. Unusual isotope effects on the pseudogap in high-Tc cuprate superconductors as support for the BCS-like pairing theory of large polarons above Tc

    Science.gov (United States)

    Dzhumanov, S.; Baimatov, P. J.; Djumanov, Sh. S.

    2015-06-01

    The BCS-like pairing theory is extended to the intermediate coupling regime and to the cases of exotic cuprate superconductors with large and small Fermi surfaces, so as to describe the pairing correlations above Tc , the opening of a pseudogap (PG) at a mean-field temperature T∗ >Tc and the unusual isotope effects on the PG in these materials within the large polaron model and two different BCS-like approaches. We argue that unconventional electron-phonon interactions are responsible for the polaron formation and the separation between temperatures T∗ (the onset of precursor Cooper pairing) and Tc (the onset of the superconducting transition) in exotic cuprate superconductors. Using the extended BCS-like approaches, we calculate the PG formation temperature T∗ , isotope shifts ΔT∗ , oxygen and copper isotope exponents and show that isotope effects on the PG basically depend on strengths of Coulomb and electron-phonon interactions, doping levels and dielectric constants of the cuprates. The new BCS-like pairing theory of polaronic carriers predicts the existence of small and sizable positive oxygen isotope effect and very large negative oxygen and copper isotope effects on the PG in the cuprates with large Fermi surfaces. The calculated results for T∗ , isotope shifts and exponents are compared with experimental data on various cuprate superconductors. For all the considered cases, a good quantitative agreement was found between theory and experimental data. We also predict the existence of small and sizable negative isotope effects on T∗ in deeply underdoped cuprates with small Fermi surfaces. Further, we find that the isotope effects on T∗ (=Tc) in heavily overdoped cuprates just like in some metals are relatively small positive or become even negative.

  10. Effect of La-CO substitution on the crystal structure and magnetic properties of low temperature sintered Sr1-xLaxFe12-xCoxO19 (x=0-0.5) ferrites

    Science.gov (United States)

    Peng, Long; Li, Lezhong; Wang, Rui; Hu, Yun; Tu, Xiaoqiang; Zhong, Xiaoxi

    2015-11-01

    The La-Co substituted Sr1-xLaxFe12-xCoxO19 (x=0-0.5) ferrites with appropriate Bi2O3 additive were prepared at a low sintering temperature of 890 °C compatible with LTCC (low temperature co-fired ceramics) systems, and the effect of La-Co substitution on their crystal structure and magnetic properties was investigated. The results show that the pure M-type phase is successfully obtained when the La-Co substitution amount x does not exceed 0.3. However, the single M-type phase structure transforms to multiphase structure with further increased x, where the α-Fe2O3 phase and La2O3 phase coexist with the M-type phase. Moreover, the saturation magnetization Ms, magnetic anisotropy field Ha, intrinsic coercivity Hci, and Curie temperature TC of the ferrites depend on the La-Co substitution amount strongly, which are suggested to be determined by the partially substitution of La3+-Co2+ ions for Sr2+-Fe3+ ions with x not higher than 0.3. It is found that the obtained Sr1-xLaxFe12-xCoxO19 (x=0.2 and 0.3) ferrites can provide improved magnetic properties (Ms>62 emu/g, Ha>1400 kA/m, and Hci>320 kA/m) as low temperature sintered M-type hexaferrites for microwave LTCC applications.

  11. Ferroelectric, piezoelectric, and dielectric properties of BiScO3-PbTiO3-Pb(Cd1/3Nb2/3)O3 ternary high temperature piezoelectric ceramics

    Science.gov (United States)

    Zhao, Tian-Long; Chen, Jianguo; Wang, Chun-Ming; Yu, Yang; Dong, Shuxiang

    2013-07-01

    (0.95-x)BiScO3-xPbTiO3-0.05Pb(Cd1/3Nb2/3)O3 (BS-xPT-PCN) high temperature piezoelectric ceramics near the morphotropic phase boundary (MPB) have been synthesized by traditional solid-state reaction methods. The microstructural morphology, phase structure, and electrical properties of BS-xPT-PCN ceramics were investigated in detail. X-ray diffraction analysis indicated BS-xPT-PCN ceramics have a pure perovskite structure. The coexistence of rhombohedral and tetragonal phases at MPB composition enhanced the polarizability by the coupling between two dynamically equivalent energy states, resulting in the improved piezoelectric and ferroelectric properties at MPB vicinity. The BS-xPT-PCN (x = 0.60) ceramics possess the optimal piezoelectric and ferroelectric properties with d33 = 505pC/N, kp = 55.9%, kt = 36.5%, strain = 0.23% (under the electric field 37.5 kV/cm), and Pr = 39.7 μC/cm2. High temperature dielectric behaviors showed diffuse phase transition in BS-xPT-PCN ceramics. The Curie temperature Tc was found to increase from 371 °C to 414 °C with x increasing from 0.58 to 0.62. All these results together with the good thermal stabilities make the BS-xPT-PCN ceramics promising candidates for high temperature piezoelectric applications.

  12. High temperature superconductivity the road to higher critical temperature

    CERN Document Server

    Uchida, Shin-ichi

    2015-01-01

    This book presents an overview of material-specific factors that influence Tc and give rise to diverse Tc values for copper oxides and iron-based high- Tc superconductors on the basis of more than 25 years of experimental data, to most of which the author has made important contributions. The book then explains why both compounds are distinct from others with similar crystal structure and whether or not one can enhance Tc, which in turn gives a hint on the unresolved pairing mechanism. This is an unprecedented new approach to the problem of high-temperature superconductivity and thus will be inspiring to both specialists and non-specialists interested in this field.   Readers will receive in-depth information on the past, present, and future of high-temperature superconductors, along with special, updated information on what the real highest Tc values are and particularly on the possibility of enhancing Tc for each member material, which is important for application. At this time, the highest Tc has not been...

  13. Superconducting fluctuations and pseudogap in high-Tc cuprates

    Directory of Open Access Journals (Sweden)

    Alloul H.

    2012-03-01

    Full Text Available Large pulsed magnetic fields up to 60 Tesla are used to suppress the contribution of superconducting fluctuations (SCF to the ab-plane conductivity above Tc in a series of YBa2Cu3O6+x. These experiments allow us to determine the field Hc’(T and the temperature Tc’ above which the SCFs are fully suppressed. A careful investigation near optimal doping shows that Tc’ is higher than the pseudogap temperature T*, which is an unambiguous evidence that the pseudogap cannot be assigned to preformed pairs. Accurate determinations of the SCF contribution to the conductivity versus temperature and magnetic field have been achieved. They can be accounted for by thermal fluctuations following the Ginzburg-Landau scheme for nearly optimally doped samples. A phase fluctuation contribution might be invoked for the most underdoped samples in a T range which increases when controlled disorder is introduced by electron irradiation. Quantitative analysis of the fluctuating magnetoconductance allows us to determine the critical field Hc2(0 which is found to be be quite similar to Hc’ (0 and to increase with hole doping. Studies of the incidence of disorder on both Tc’ and T* allow us to to propose a three dimensional phase diagram including a disorder axis, which allows to explain most observations done in other cuprate families.

  14. Effect of Al substitution on magnetocaloric effect in La{sub 0.57}Nd{sub 0.1}Sr{sub 0.33}Mn{sub 1-x}Al{sub x}O{sub 3} (0.0 {<=} x {<=} 0.30) polycrystalline near room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tka, Emna, E-mail: emna_tka@yahoo.fr [Unite de Recherche Physique des Solides, Departement de Physique, Faculte des Sciences de Monastir, 5019, Universite de Monastir (Tunisia); Cherif, Karima; Dhahri, Jemai [Unite de Recherche Physique des Solides, Departement de Physique, Faculte des Sciences de Monastir, 5019, Universite de Monastir (Tunisia); Dhahri, Essebti [Laboratoire de Physique Applique, Faculte des Sciences, B.P. 1171, 3000 Sfax, Universite de Sfax (Tunisia); Belmabrouk, Hafedh [Laboratoire de Micro Electronique, Departement de Physique, Faculte des sciences de Monastir, 5019, Universite de Monastir (Tunisia); Hlil, El Kebir [Laboratoire de Cristallographie, CNRS, 25 avenue des Martyrs, B.P. 166, 38042 Grenoble-Cedex 9 (France)

    2012-03-25

    Highlights: Black-Right-Pointing-Pointer The magnetocaloric effect in La{sub 0.57}Nd{sub 0.1}Sr{sub 0.33}Mn{sub 1-x}Al{sub x}O{sub 3} materials was investigated. Black-Right-Pointing-Pointer The decrease of TC is accompanied by an increase of upon 10 kOe applied field variation. Black-Right-Pointing-Pointer Q{sub M} as well as RCP increases with Al-doping. - Abstract: We have investigated the effect of aluminum (Al) doping on the magnetic and magnetocaloric properties of La{sub 0.57}Nd{sub 0.1}Sr{sub 0.33}Mn{sub 1-x}Al{sub x}O{sub 3} (LNSMAO) (0.0 {<=} x {<=} 0.3). The Curie temperature T{sub C} of the prepared samples is found to be strongly dependent on the aluminum content and it spans between 238 K and 342 K. It has been analyzed by using two methods: a linear extrapolation of M (T) to zero magnetization and the thermodynamic model. With an increasing Al concentration, a systematic increase in the values of magnetic entropy is observed. The magnitude of the isothermal magnetic entropy (|{Delta}S{sub M}|) at the FM Curie temperature increases from 2.31 J/kg K for x = 0 to a maximum value of 3.58 J/kg K for x = 0.3 for a magnetic field change of 10 kOe. Moreover, the relative cooling power (RCP) increases from 23 J/kg to 68 J/kg, respectively. Large magnetic entropy changes upon the application of a low magnetic field and a wide temperature range of T{sub C} suggest that these materials can be used as candidates for magnetic refrigerants.

  15. Classification of species in the genus Penicillium by Curie point pyrolysis/mass spectrometry followed by multivariate analysis and artificial neural networks

    DEFF Research Database (Denmark)

    Nilsson, Torben; Bassani, Maria R.; Larsen, Thomas Ostenfeld

    1996-01-01

    linkage clustering. By this approach a successful classification of the species Penicillium italicum, P. expansum and P. digitatum originating from fruits was obtained. Isolates of the same species grouped together in the dendrogram, while the different species were distinguished. Also when grown on two......Curie point pyrolysis/mass spectrometry of Penicillium species was performed with 530 degrees C Curie point foils. The mass spectra were submitted to principal component analysis, canonical variates analysis and hierarchical cluster analysis, producing a final dendrogram by the use of average...... in a correct classification in all cases. Thus, it is concluded that Curie point pyrolysis/mass spectrometry is useful in chemotaxonomic studies of the closely related species in the genus Penicillium....

  16. Angular dependence of dipole-dipole-Curie-spin cross-correlation effects in high-spin and low-spin paramagnetic myoglobin.

    Science.gov (United States)

    Pintacuda, Guido; Hohenthanner, Karin; Otting, Gottfried; Müller, Norbert

    2003-10-01

    The (15)N-HSQC spectra of low-spin cyano-met-myoglobin and high-spin fluoro-met-myoglobin were assigned and dipole-dipole-Curie-spin cross-correlated relaxation rates measured. These cross-correlation rates originating from the dipolar (1)H-(15)N interaction and the dipolar interaction between the (1)H and the Curie spin of the paramagnetic center contain long-range angular information about the orientation of the (1)H-(15)N bond with respect to the iron-(1)H vector, with information measurable up to 11 A from the metal for the low-spin complex, and between 10 to 25 A for the high-spin complex. Comparison of the experimental data with predictions from crystal structure data showed that the anisotropy of the magnetic susceptibility tensor in low spin cyano-met-myoglobin significantly influences the cross-correlated dipole-dipole-Curie-spin relaxation rates.

  17. Retention of 99mTc-DMSA(III) and 99mTc-nanocolloid in different syringes affects imaging quality.

    Science.gov (United States)

    Bauwens, Matthias; Pooters, Ivo; van der Pol, Jochen; Mottaghy, Felix M; van Kroonenburgh, Marinus

    2014-04-01

    (99m)Tc-dimercaptosuccinic acid [DMSA(III)] and colloidal human serum albumin ((99m)Tc-nanocolloid) are widely used radiopharmaceuticals. Recently, in our institution we encountered image quality problems in DMSA scans after changing the brand of syringes we were using, which triggered us to look into the adsorption properties of syringes from different brands for (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid. We also describe a clinical case in which adsorption of (99m)Tc-DMSA(III) caused inferior imaging quality. DMSA and nanocolloid were labeled with (99m)Tc following manufacturer guidelines. After synthesis, syringes with (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid were stored for 15, 30, 60, and 120 min. We evaluated Luer Lock syringes manufactured by different brands such as Artsana, Henke-Sass-Wolf, B. Braun Medical N.V., CODAN Medizinische Geräte GmbH & Co KG, Becton Dickinson and Company, and Terumo Europe. Adsorption of (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid was acceptably low for all syringes (image quality--for example, in DMSA scans using pediatric radiopharmaceutical doses. It is advised to check the compatibility of any radiopharmaceutical with syringes as an integral part of the quality assurance program.

  18. Synthesis and biodistribution of a novel (⁹⁹m)TcN complex of norfloxacin dithiocarbamate as a potential agent for bacterial infection imaging.

    Science.gov (United States)

    Zhang, Shijian; Zhang, Weifang; Wang, Yue; Jin, Zhonghui; Wang, Xuebin; Zhang, Junbo; Zhang, Yanyan

    2011-03-16

    Achieving a (⁹⁹m)Tc-labeled fluoroquinolone derivative as a single photon emission computed tomography (SPECT) tracer is considered to be of great interest. The norfloxacin dithiocarbamate (NFXDTC) was synthesized and radiolabeled with a [(⁹⁹m)TcN]²(+) intermediate to form the (⁹⁹m)TcN-NFXDTC complex in high yield. The radiochemical purity of (⁹⁹m)TcN-NFXDTC was over 90%, as measured by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC), without any notable decomposition at room temperature over a period of 6 h. The partition coefficient and electrophoresis results indicated that (⁹⁹m)TcN-NFXDTC was lipophilic and neutral. The bacterial binding assay studies showed tht (⁹⁹m)TcN-NFXDTC had a good binding affinity. Biodistribution results in bacterial infected mice showed that (⁹⁹m)TcN-NFXDTC had a higher uptake at the sites of infection and better abscess/blood and abscess/muscle ratios than those of (⁹⁹m)Tc-ciprofloxacin and (⁹⁹m)TcN-CPFXDTC (CPFXDTC = ciprofloxacin dithiocarbamate). The biodistribution results of (⁹⁹m)TcN-NFXDTC in bacterially infected mice and in mice with turpentine-induced abscesses indicated that (⁹⁹m)TcN-NFXDTC was suited to be a bacteria-specific infection imaging agent. Single photon emission computed tomography (SPECT) image studies showed there was a visible accumulation in infection sites, suggesting that it would be a promising candidate for bacterial infection imaging.

  19. Ferromagnetic vortex core switching at elevated temperatures

    Science.gov (United States)

    Lebecki, Kristof M.; Nowak, Ulrich

    2014-01-01

    An approach for the investigation of vortex core switching is presented. Thermal effects up to the Curie point are included in a micromagnetic framework based on the recently developed Landau-Lifshitz-Bloch equation. In this approach it is easier to avoid numerical discretization artifacts, commonly present when a Bloch point is mediating the switching process. Switching in thin circular permalloy disks caused by the application of a slowly increasing magnetic field oriented orthogonally to the disk is considered. An energy barrier which can be overcome by thermal fluctuations is taken into account, leading to a strong influence of the temperature on the switching field. In particular, the switching field goes to zero at a significantly smaller temperature than the Curie temperature. The deduced nucleation volume is smaller than the typical grain size in permalloy.

  20. Inductance measurements in multilevel high Tc step-edge grain boundary SQUIDS

    Science.gov (United States)

    Forrester, M. G.; Davidson, A.; Talvacchio, J.; Gavaler, J. R.; Przybysz, J. X.

    1994-10-01

    Multilevel high Tc SQUIDs, suitable for digital circuit applications, have been fabricated and tested. The devices employ a YBa2Cu3O7-δ (YBCO) ground plane, an epitaxial SrTiO3 insulator, and a YBCO microstrip layer. Junctions are formed by the step-edge grain boundary process, with a ground plane contact for the ``low'' side of each junction, using only isotropic sputtering and milling techniques. Control current is directly injected in a microstrip segment of the SQUID loop, allowing us to measure the microstrip inductance, and thus to infer the magnetic penetration depth of the YBCO. The SQUIDs are operational above 77 K, at which temperature we infer a penetration depth of 350 nm. The temperature dependence of the penetration depth is found to be in reasonable agreement with the Gorter-Casimir form close to Tc.

  1. Kinetic inductance effects in high-Tc microstrip circuits at microwave frequencies

    Science.gov (United States)

    Byrne, D. P.; Kwor, R.; Kalkur, T. S.

    1990-10-01

    This paper describes the fabrication of high-Tc superconducting thin films of BiCaSrCuO and the patterning of these films into integrated microstrip transmission line resonators designed to exhibit the effects of kinetic inductance. Emphasis is given to techniques to fabricate very thin, low-loss dielectric layers on BiCaSrCuO. Microwave S-parameter measurements on these resonators are reported along with functional dependence of tranmission line phase velocity and the characteristic impedance with temperature and microwave power density, especially at temperatures just below Tc. The results are used to infer high-frequency penetration depths and surface resistivities in BiCaSrCuO.

  2. sup 99m Tc renal tubular function agents: Current status

    Energy Technology Data Exchange (ETDEWEB)

    Eshima, D.; Fritzberg, A.R.; Taylor, A. Jr. (Emory Univ. School of Medicine, Atlanta, GA (USA))

    1990-01-01

    Orthoiodohippuric (OIH) acid labeled with 131I is a widely used renal radiopharmaceutical agent and has been the standard radiopharmaceutical agent for the measurement of effective renal plasma flow (EPRF). Limitations to the routine clinical use of 131I OIH are related to the suboptimal imaging properties of the 131I radionuclide and its relatively high radiation dose. 123I has been substituted for 131I; however, its high cost and short shelf-life have limited its widespread use. Recent work has centered on the development of a new 99mTc renal tubular function agent, which would use the optimal radionuclidic properties and availability of 99mTc and combine the clinical information provided by OIH. The search for a suitable 99mTc renal tubular function agent has focused on the diamide dithiolate (N2S2), the paraaminohippuric iminodiacetic acid (PAHIDA), and the triamide mercaptide (N3S) donor ligand systems. To date, the most promising 99mTc tubular function agent is the N3S complex: 99mTc mercaptoacetyltriglycine (99mTc MAG3). Studies in animal models in diuresis, dehydration, acid or base imbalance, ischemia, and renal artery stenosis demonstrate that 99mTc MAG3 behaves similarly to 131I OIH. A simple kit formulation is available that yields the 99mTc MAG3 complex in high radiochemical purity. Studies in normal subjects and patients indicate that 99mTc MAG3 is an excellent 99mTc renal tubular agent, but its plasma clearance is only 50% to 60% that of OIH. In an effort to develop an improved 99mTc renal tubular function agent, changes have been made in the core N3S donor ligand system, but to date no agent has been synthesized that is clinically superior to 99mTc MAG3. 61 references.

  3. 高温压电材料的概况及发展趋势%Development of high Tc piezoelectric ceramics

    Institute of Scientific and Technical Information of China (English)

    石维; 冉耀宗; 左江红; 王强; 陶涛; 欧永康

    2011-01-01

    介绍了高温压电材料的研究现状,综述了钙钛矿、钨青铜型、铋层状、碱金属铌酸盐结构体系4种不同压电陶瓷的结构及研究情况,并指出了高居里点压电陶瓷的研究方向和发展趋势。%This paper reviewed the high Curie temperature piezoelectric materials, including tungsten bronze, bismuth layer structured, Perovskite types piezoelectric ceramics and corundum structure ceramics. The research studies on the development of four different structure types high curies piezoelectric ceramics were also reviewed. In addition, the research direction and piezoelectric ceramic development trend were discussed.

  4. Observed warming trend in sea surface temperature at tropical cyclone genesis

    Science.gov (United States)

    Defforge, Cécile L.; Merlis, Timothy M.

    2017-01-01

    Tropical cyclone (TC) activity is influenced by environmental factors, and it is expected to respond to anthropogenic climate change. However, there is observational uncertainty in historical changes in TC activity, and attributing observed TC changes to anthropogenic forcing is challenging in the presence of internal climate variability. The sea surface temperature (SST) is a well-observed environmental factor that affects TC intensity and rainfall. Here we show that the SST at the time of TC genesis has a significant warming trend over the three decades of the satellite era. Though TCs are extreme events, the warming trend at TC genesis is comparable to the trend in SST during other tropical deep convection events and the trend in SST in the TC main development regions throughout the TC season. This newly documented, observed signature of climate change on TC activity is also present in high-resolution global atmospheric model simulations that explicitly simulate TCs.

  5. 合成温度对La0.85K0.15MnO3纳米颗粒磁性能的影响%Effect of Synthesis Temperature on Magnetocaloric Properties of La0.85 K0.15MnO3 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    李丽荣; 赵娟; 王贵; 罗龙

    2012-01-01

    In this paper, the nanosized particles of La0.85Kg0.15MnO3 perovskite - type oxides were sucessfully synthesized at relatively low calcinated temperature by using amorphous heteronuclear complexing method. The relationship between mag-netocaloric properties and the calcined temperature of La0.85Kg0.15MnO3 MnO, nanoparticles was investigated systematically. The result of PPMS( Physical Property Measurement System) measurement shows that the Curie temperature Tc is 274.5 K and is independent of the calcined temperature within range of 600℃- 1000℃, the maximum magnetic entropy changes close to Tc(274 K ) of the samples calcined at 600℃ , 800℃ and 1000℃ are 2.02,3.06 and 3.56 J/kg · K at H = 2T. However, the Curie temperature of sample calcined at 1200℃ for 10h is 242.9K, which means that the magneticaloric property of the Lao.85 K0.15 MnO3 nanoparticles can be precisely controlled by adjusting the heat treatment process.%采用非晶态配合物前躯体法在比较低的烧结温度合成了钙钛矿结构氧化物La0.55K0.15MnO3纳米颗粒,系统的研究了烧结温度对Ia0.85K0.15 MnO3纳米颗粒磁性能的影响,用PPMS测量样品的居里温度和磁性能,结果表明烧结温度范围在600℃ ~ 1000℃之间,居里温度Tc为274.5 K,和烧结温度没有明显关系,在H=2T时,烧结温度分别为600℃,800℃,1000℃,对应的磁熵变△SM分别是2.02 J/(kg·K),3.06 J/(kg·K),3.56 J/(kg·K),当烧结温度升高到1200.C时,居里温度Tc为242.9K,通过控制烧结温度来调节La0.85K0.15MnO3纳米颗粒的磁性能.

  6. Electronic Raman scattering as a function of doping in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kendziora, C. [Naval Research Lab., Washington, DC (United States); Kelley, R.J.; Onellion, M. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.

    1996-12-31

    The authors report the results of Raman scattering from the electronic continuum in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi 2212) and Ti{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl 2201) high temperature superconductors with variations in the oxygen content, {delta}. Below {Tc}, a peak develops in the Raman continuum associated with the opening of a superconducting gap, {Delta}(k). By selecting the polarizations of incident and scattered light, they are sensitive to possible anisotropy of the gap within the a-b plane. Near optimal doping, both materials show gap anisotropy, with 2{Delta}/k{sub B}{Tc} values of 7.2 (B{sub 1g}) vs. 5.8 (A{sub 1g}) in Tl 2202 and 8.5 (B{sub 1g}) vs. 6.2 (A{sub 1g}) in Bi 2212. In contrast, both show an isotropic gap at much lower energy shifts when the carrier concentration is raised: 2{Delta}/k{sub B}{Tc} = 3.9 (5.5) for Tl 2201 (Bi 2212) with {Tc} = 37K (57K). The authors compare the observed spectra with calculations based on order parameters with d-wave as well as isotropic s-wave symmetry and conclude that raising the doping level reduces the gap anisotropy to near zero.

  7. Modification of both d33 and TC in a potassium-sodium niobate ternary system.

    Science.gov (United States)

    Wu, Bo; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo

    2015-12-28

    In this work, we simultaneously achieved a giant d33 and a high TC in a lead-free piezoelectric ternary system of (1-x-y)K0.48Na0.52NbO3-xBiFeO3-yBi0.5Na0.5ZrO3 {(1-x-y)KNN-xBF-yBNZ}. Owing to the rhombohedral-orthorhombic-tetragonal (R-O-T) phase coexistence and the enhanced dielectric and ferroelectric properties, the ceramics with a composition of (x = 0.006, y = 0.04) show a giant d33 of ∼428 pC N(-1) together with a TC of ∼318 °C, thereby proving that the design of ternary systems is an effective way to achieve both high d33 and high TC in KNN-based materials. In addition, a good thermal stability for piezoelectricity was also observed in these ceramics (e.g., d33 > 390 pC N(-1), T ≤ 300 °C). This is the first time such a good comprehensive performance in potassium-sodium niobate materials has been obtained. As a result, we believe that this type of material system with both giant d33 and high TC is a promising candidate for high-temperature piezoelectric devices.

  8. Magnetoencephalography based on high-Tc superconductivity: a closer look into the brain?

    CERN Document Server

    Öisjöen, F; Figueras, G A; Chukharkin, M L; Kalabukhov, A; Hedström, A; Elam, M; Winkler, D

    2011-01-01

    Magnetoencephalography (MEG) enables the study of brain activity by recording the magnetic fields generated by neural currents and has become an important technique for neuroscientists in research and clinical settings. Unlike the liquid-helium cooled low-Tc superconducting quantum interference devices (SQUIDs) that have been at the heart of modern MEG systems since their invention, high-Tc SQUIDs can operate with liquid nitrogen cooling. The relaxation of thermal insulation requirements allows for a reduction in the stand-off distance between the sensor and the room-temperature environment from a few centimeters to less than a millimeter, where MEG signal strength is significantly higher. Despite this advantage, high-Tc SQUIDs have only been used for proof-of-principle MEG recordings of well-understood evoked activity. Here we show high-Tc SQUID-based MEG may be capable of providing novel information about brain activity due to the close proximity of the sensor to the head. We have performed single- and two-...

  9. IEC TC104工作动态

    Institute of Scientific and Technical Information of China (English)

    陈洁

    2000-01-01

    @@1 IECTC104简介 IEC TC104是由原来的IEC TC50(环境试验技术委员会)和IEC TC75(环境条件的分类分级委员会)两个技术委员会于1997年6月合并组成的一个技术委员会,其全称为“环境条件、分类和试验方法技术委员会”。 IEC TC104的工作范围是:

  10. 99mTc-ciprofloxacin for diagnosis of bacterial infection

    Science.gov (United States)

    Aungurarat, A.; Ngamprayad, T.; Dangprasert, M.; Phumkem, S.; Jowanaridhi, B.

    2015-05-01

    Preparation of 99mTc-ciprofloxacin for diagnosis of bacterial infection was investigated by varying factors which affected this compound. The optimum conditions for preparation of 99mTc-ciprofloxacin and a lyophilized kit for Tc-99m labelling were studied. The results from biodistribution study showed that the percentages of the injected dose per gram tissues of infected area at 1 and 3 hours after injection were around 0.25-0.56. 99mTc-ciprofloxacin was found sterile, pyrogen-free and non-toxic. Radiochemical purity was greater than 90% with greater than 6 hours of stability.

  11. A novel 99mTc-labeled molecular probe for tumor angiogenesis imaging in hepatoma xenografts model: a pilot study.

    Directory of Open Access Journals (Sweden)

    Qian Zhao

    Full Text Available INTRODUCTION: Visualization of tumor angiogenesis using radionuclide targeting provides important diagnostic information. In previous study, we proved that an arginine-arginine-leucine (RRL peptide should be a tumor endothelial cell specific binding sequence. The overall aim of this study was to evaluate whether (99mTc-radiolabeled RRL could be noninvasively used for imaging of malignant tumors in vivo, and act as a new molecular probe targeting tumor angiogenesis. METHODS: The RRL peptide was designed and radiosynthesized with (99mTc by a one-step method. The radiolabeling efficiency and radiochemical purity were then characterized in vitro. (99mTc-RRL was injected intravenously in HepG2 xenograft-bearing BALB/c nude mice. Biodistribution and in vivo imaging were performed periodically. The relationship between tumor size and %ID uptake of (99mTc-RRL was also explored. RESULTS: The labeling efficiencies of (99mTc-RRL reached 76.9% ± 4.5% (n = 6 within 30-60 min at room temperature, and the radiochemical purity exceeded 96% after purification. In vitro stability experiment revealed the radiolabeled peptide was stable. Biodistribution data showed that (99mTc-RRL rapidly cleared from the blood and predominantly accumulated in the kidneys and tumor. The specific uptake of (99mTc-RRL in tumor was significantly higher than that of unlabeled RRL blocking and free pertechnetate control test after injection (p<0.05. The ratio of the tumor-to-muscle exceeded 6.5, tumor-to-liver reached 1.98 and tumor-to-blood reached 1.95. In planar gamma imaging study, the tumors were imaged clearly at 2-6 h after injection of (99mTc-RRL, whereas the tumor was not imaged clearly in blocking group. The tumor-to-muscle ratio of images with (99mTc-RRL was comparable with that of (18F-FDG PET images. Immunohistochemical analysis verified the excessive vasculature of tumor. There was a linear relationship between the tumor size and uptake of (99mTc-RRL with R(2 = 0

  12. Tc trends and terrestrial planet formation: The case of Zeta Reticuli

    OpenAIRE

    Adibekyan Vardan; Elisa Delgado-Mena; Pedro Figueira; Sergio Sousa; Nuno Santos; Joao Faria; Jonay González Hernández; Garik Israelian; Gohar Harutyunyan; Lucia Suárez-Andrés; Arthur Hakobyan

    2016-01-01

    During the last decade astronomers have been trying to search for chemical signatures of terrestrial planet formation in the atmospheres of the hosting stars. Several studies suggested that the chemical abundance trend with the condensation temperature, Tc, is a signature of rocky planet formation.  In particular, it was suggested that the Sun shows 'peculiar' chemical abundances due to the presence of the terrestrial planets in our solar-system. However, the rocky material accretion or the t...

  13. High Tc Superconducting Materials for Strong Current Applications: Approach at the First Stage

    Institute of Scientific and Technical Information of China (English)

    JIN Jian-xun

    2007-01-01

    Strong current and large-scale application is the most important prospect of high Tc superconductors (HTS). Practical HTS samples in various forms have been produced with high critical currents operated at economic cryogenic temperatures. Engineering applications of those HTS materials have been studied with various HTS prototype devices. The applicable HTS materials produced in different forms are verified in this paper with regard to their strong current characterizations, and the HTS applications are summarized along with the HTS prototypes made.

  14. Coherent center domains in SU(3) gluodynamics and their percolation at T_c

    CERN Document Server

    Gattringer, Christof

    2010-01-01

    For SU(3) lattice gauge theory we study properties of static quark sources represented by local Polyakov loops. We find that for temperatures both below and above T_c coherent domains exist where the phases of the local loops have similar values in the vicinity of the center values 0, +/- 2 pi/3. The cluster properties of these domains are studied numerically. We demonstrate that the deconfinement transition of SU(3) may be characterized by the percolation of suitably defined clusters.

  15. curi y bacánowa: Rituales de vida y muerte en la sierra tarahumara

    Directory of Open Access Journals (Sweden)

    Ángel Acuña Delgado

    2009-01-01

    Full Text Available En base a los datos obtenidos durante los once meses de experiencia de campo, entre 2001 y 2005, en varias comunidades rarámuris de la Alta y Baja Tarahumara, al suroeste del estado de Chihuahua (México, en el presente trabajo centramos la atención en dos rituales y al mismo tiempo formas de danza, ambos de carácter privado, que ocupan un papel esencial en la cosmovisión rarámuri. El hecho de haber participado como espectador invitado en tales prácticas nos permitirá describir el contexto etnográfico de primera mano; para finalizar destacando especialmente las funciones y significados que llevan asociados. Antes ofreceremos, no obstante, una serie de referencias bibliográficas que sitúan al jícuri y al bacánowa entre la historia y la leyenda.

  16. Redefining the Poet as Healer: Valerie Gillies's Collaborative Role in the Edinburgh Marie Curie Hospice Quiet Room Project.

    Science.gov (United States)

    Severin, Laura

    2015-01-01

    This article examines the poetic contribution of Valerie Gillies, Edinburgh Makar (or poet of the city) from 2005-2008, to the Edinburgh Marie Curie Hospice Quiet Room, a new contemplation space for patients, families, and staff. In collaboration with others, Gillies created a transitional space for the Quiet Room, centered on the display of her sonnet, "A Place Apart." This space functions to comfort visitors to the Quiet Room by relocating them in their surroundings and offering the solace provided by nature and history. With this project, her first as Edinburgh Makar, Gillies redefines the role of the poet as healer and advocates for newer forms of palliative care that focus on patients' spiritual and emotional, as well as physical, wellbeing.

  17. Introduction to the EC's Marie Curie Initial Training Network (MC-ITN) project: Particle Training Network for European Radiotherapy (PARTNER)

    CERN Document Server

    Dosanjh, Manjit

    2013-01-01

    PARTNER (Particle Training Network for European Radiotherapy) is a project funded by the European Commission’s Marie Curie-ITN funding scheme through the ENLIGHT Platform for 5.6 million Euro. PARTNER has brought together academic institutes, research centres and leading European companies, focusing in particular on a specialized radiotherapy (RT) called hadron therapy (HT), interchangeably referred to as particle therapy (PT). The ultimate goal of HT is to deliver more effective treatment to cancer patients leading to major improvement in the health of citizens. In Europe, several hundred million Euro have been invested, since the beginning of this century, in PT. In this decade, the use of HT is rapidly growing across Europe, and there is an urgent need for qualified researchers from a range of disciplines to work on its translational research. In response to this need, the European community of HT, and in particular 10 leading academic institutes, research centres, companies and small and medium-sized en...

  18. Direct {sup 99m}Tc labeling of Herceptin (trastuzumab) by {sup 99m}Tc(I) tricarbonyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.-J.; Yen, C.-L.; Lo, S.-T.; Chen, K.-T. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lo, J.-M. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China)], E-mail: jmlo@mx.nthu.edu.tw

    2008-03-15

    By simply incubating Herceptin (trastuzumab) with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +} ion in saline, a significant yield of {sup 99m}Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which {sup 99m}Tc(I) tricarbonyl ion can be strongly bound. For practical {sup 99m}Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, {alpha}-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +}. Retention of bioactivity of the {sup 99m}Tc(I)-labeled trastuzumab was validated using a cell binding test.

  19. Expanding the knowledge of the geographic distribution of Trypanosoma cruzi TcII and TcV/TcVI genotypes in the Brazilian Amazon.

    Science.gov (United States)

    Lima, Valdirene Dos Santos; Xavier, Samanta Cristina das Chagas; Maldonado, Irene Fabíola Roman; Roque, André Luiz Rodrigues; Vicente, Ana Carolina Paulo; Jansen, Ana Maria

    2014-01-01

    Trypanosoma cruzi infection is a complex sylvatic enzooty involving a wide range of animal species. Six discrete typing units (DTUs) of T. cruzi, named TcI to TcVI, are currently recognized. One unanswered question concerning the epidemiology of T. cruzi is the distribution pattern of TcII and hybrid DTUs in nature, including their virtual absence in the Brazilian Amazon, the current endemic area of Chagas disease in Brazil. Herein, we characterized biological samples that were collected in previous epizootiological studies carried out in the Amazon Basin in Brazil. We performed T. cruzi genotyping using four polymorphic genes to identify T. cruzi DTUs: mini-exon, 1f8, histone 3 and gp72. This analysis was conducted in the following biological samples: (i) two T. cruzi isolates obtained by culturing of stools from the triatomine species Rhodnius picttipes and (ii) five serum samples from dogs in which trypomastigotes were observed during fresh blood examination. We report for the first time the presence of TcII and hybrid DTUs (TcV/TcVI) in the Amazon region in mixed infections with TcI. Furthermore, sequencing of the constitutive gene, gp72, demonstrated diversity in TcII even within the same forest fragment. These data show that TcII is distributed in the five main Brazilian biomes and is likely more prevalent than currently described. It is very probable that there is no biological or ecological barrier to the transmission and establishment of any DTU in any biome in Brazil.

  20. 99Tc Process Monitoring System In-Lab Performance Characterization

    Energy Technology Data Exchange (ETDEWEB)

    O' Hara, Matthew J.; Niver, Cynthia M.

    2014-01-01

    Executive Summary A 99Tc Process Monitoring (Tc-Mon) System has been designed and built for deployment at the recently constructed 200 West Pump & Treat (200W P&T) Plant in the 200 West Area ZP-1 Operable Unit of the Hanford Site. The plant is operated by CH2M Hill Plateau Remediation Company (CHPRC). The Tc-Mon system was created through collaboration between Pacific Northwest National Laboratory (PNNL) and Burge Environmental, Inc. The new system’s design has been optimized based on experience from an earlier field test (2011) of a prototype system at the 200W-ZP-1 Interim Pump & Treat Plant. A portion of the new 200W P&T Plant is dedicated to removal of 99Tc from contaminated groundwater in the 200 West Area. 99Tc, as the pertechnetate anion (99TcO4-), is remediated through delivery of water into two trains (Trains A and B) of three tandem extraction columns filled with Purolite A530E resin. The resin columns cannot be regenerated; therefore, once they have reached their maximum useful capacity, the columns must be disposed of as radioactive waste. The Tc-Mon system’s primary duty will be to periodically sample and analyze the effluents from each of the two primary extraction columns to determine 99Tc breakthrough. The Tc-Mon system will enable the CH2M Hill Plateau Remediation Company (CHPRC) to measure primary extraction column breakthrough on demand. In this manner, CHPRC will be able to utilize each extraction column to its maximum capacity. This will significantly reduce column disposal and replacement costs over the life of the plant. The Tc-Mon system was constructed by Burge Environmental, Inc. and was delivered to PNNL in June 2013 for setup and initial hardware and software performance testing in the 325 Building. By early July, PNNL had initiated an in-laboratory performance characterization study on the system. The objective was to fully calibrate the system and then evaluate the quality of the analytical outputs 1) against a series of clean

  1. Comparison of Friction Wear Properties between TC4 Titanium Alloy and P110 Tubing Steel%TC4合金和P110油管钢摩擦磨损性能的比较

    Institute of Scientific and Technical Information of China (English)

    姚小飞; 谢发勤; 韩勇; 赵国仙; 吴向清

    2012-01-01

    TC4合金和P110油管钢在不同温度下的摩擦磨损性能进行对比研究,分析其摩擦系数、磨损率和磨痕形貌随温度的变化规律,探讨磨损机制.结果表明:P110油管钢的耐磨性明显优于TC4合金,TC4合金的耐磨性随温度的升高无显著变化,磨痕呈犁沟形貌,在较低温度时的磨损机制为剥层磨损、黏着磨损和疲劳磨损,在较高温度时为剥层磨损、黏着磨损和氧化磨损;P110油管钢耐磨性随温度的升高而降低,在较低温度时磨痕呈磨坑形貌,磨损机制为剥层磨损和磨粒磨损,在较高温度时磨痕形貌呈犁沟形貌,主要为剥层磨损、黏着磨损和氧化磨损.%The friction wear properties of TC4 alloy and P110 tubing steel were comparatively studied at different temperatures. The changing rules of the wear rate, frication coefficient and topography of wear mark with the temperature were analyzed and the wear mechanism was also discussed. The results show that the wear resistance of P110 tubing steel excels obviously that of TC4 alloy. The wear resistance of TC4 changes a little with temperature rising and the wear mark is furrow morphology. The wear mechanism of TC4 alloy is delamination abrasion, adhesive abrasion and fatigue abrasion at lower temperature and delamination abrasion, adhesive abrasion and oxidation abrasion at higher temperature. The wear resistance of P110 tubing steel is decreased with temperature rising. The wear mark of P110 tubing steel is wear pit morphology and the wear mechanism is delamination abrasion and abrasive grain abrasion at lower temperature, while the wear mark is furrow morphology and the wear mechanism is delamination abrasion, adhesive abrasion and oxidation abrasion at higher temperature.

  2. Sensory characteristics of meat cooked for prolonged times at low temperature

    DEFF Research Database (Denmark)

    Christensen, Line Bach; Gunvig, Annemarie; Tørngren, Mari Ann

    2012-01-01

    The present study evaluated the sensory characteristics of low temperature long time (LTLT) treated Semitendinosus from pork and beef and Pectoralis profundus from chicken. Semitendinosus and Pectoralis profundus muscles were heat treated at 53°C and 58°C for Tc + 6 h, Tc + 17 h, and Tc + 30 h...

  3. Preperation and performance of {sup 99}Mo/{sup 99m}Tc chromatographic column generator based on zirconium molybdosilicate

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, M.; Saber, H.M.; El-Sadek, A.A. [Atomic Energy Authority, Cairo (Egypt). Hot Labs. Center; Nassar, M.Y. [Benha Univ. (Egypt). Chemistry Dept.

    2016-08-01

    Zirconium molybdosilicate (ZrMoSi) gel prepared using {sup 99}Mo radiotracer via peroxo route was used as a base material for {sup 99}Mo/{sup 99m}Tc column generator. The {sup 99m}Tc elution yield and {sup 99}Mo breakthrough in the eluate were studied as a function of the pH-value of gel precipitation, gel drying temperature and Zr: Mo: Si molar ratio. Precipitation pH-value of 2, drying temperature of 100 C and Zr: Mo: Si molar ratio of 0.5: 0.5: 1 were found to be the optimum conditions achieving {sup 99m}Tc elution yield of 82% and {sup 99}Mo breakthrough of 1.0 x 10{sup -3}%. The gel prepared with the optimum conditions was characterized by BET surface area and pore size analyzer, IR spectroscopy, thermal analysis (TGA and DTA), XRD, XRF and FESEM. Technetium-99m eluted from the optimum ZrMoSi {sup 99}Mo/{sup 99m}Tc generator was found to have a high radiochemical purity (98% as {sup 99m}TcO{sub 4}{sup -}) and chemical purity meeting criteria of clinical grade.

  4. Espalhamento Thomson no tiroide compacto TC-1

    OpenAIRE

    Luiz Angelo Berni

    1996-01-01

    Resumo: Pela primeira vez foi instalado o diagnóstico de espalhamento Thomson no Toróide Compacto TC-1 da Unicamp. Primeiramente o diagnóstico foi realizado com uma única passagem do laser de rubi ( energia: 3 J -duração: 40 ns ) pelo plasma com injeção axial e radial do laser e observado a 90° .Com a injeção axial obtivemos uma densidade de (4,3 ± 0,7)x1021 m-3 e uma temperatura eletrônica de ( 8 ± 3) eV. Estes resultados foram confirmados com a geometria radial de injeção do laser com uma d...

  5. Standardization of 99mTc.

    Science.gov (United States)

    Sahagia, Maria

    2006-01-01

    The radioactivity of 99mTc was standardized by the 4piPC-gamma coincidence method with two different modes. One is using coincidences between (119.5-142.6)keV conversion electrons and K X-rays, and the other is coincidences between the 2.13 keV conversion electrons and 140.5 keVgamma-rays. The background of the K X-ray peak and the sensitivity of the proportional counter (PC) to 140 keV gamma-rays were the main sources of uncertainties in the first case and low detection efficiency for conversion electrons in the second case. General coincidence equations were written, with specific forms, for the three measurement variants, including literature variant. Comparison with the ionization chamber calibration is reported.

  6. RILEM TC ISR Summer 2015 Activity Report

    Energy Technology Data Exchange (ETDEWEB)

    Le Pape, Yann [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    With aging infrastructures, instances of Alkali Silica Reaction (ASR) and Delayed Ettringite Formation (DEF), broadly covered under the term Internal Swelling Reaction (ISR), are increasingly being detected. They have been observed in bridges, dams, and most recently in nuclear power plants. Concrete swelling may result in bridge partial failure, dams with structural cracks and misaligned turbine shafts, and locked slice gates. For nuclear reactors micro-cracks may cause increased gas permeability which will jeopardize the containment integrity and may decrease the residual structural resistance under accidental loading. This TC, which limits its activity to structures with known expansive concrete, seeks to address two complementary but fundamental questions: a) What is the kinetics of the reaction and b) How would it affect the integrity of the structure (serviceability and strength) and thus establish a science based prognostic to the structure owner.

  7. Thin film thermistor with positive temperature coefficient of resistance based on phase separated blends of ferroelectric and semiconducting polymers

    Science.gov (United States)

    Lenz, Thomas; Sharifi Dehsari, Hamed; Asadi, Kamal; Blom, Paul W. M.; Groen, Wilhelm A.; de Leeuw, Dago M.

    2016-09-01

    We demonstrate that ferroelectric memory diodes can be utilized as switching type positive temperature coefficient (PTC) thermistors. The diode consists of a phase separated blend of a ferroelectric and a semiconducting polymer stacked between two electrodes. The current through the semiconducting polymer depends on the ferroelectric polarization. At the Curie temperature the ferroelectric polymer depolarizes and consequently the current density through the semiconductor decreases by orders of magnitude. The diode therefore acts as switching type PTC thermistor. Unlike their inorganic counterparts, the PTC thermistors presented here are thin film devices. The switching temperature can be tuned by varying the Curie temperature of the ferroelectric polymer.

  8. Evaluation of the absorbed dose to the kidneys due to Tc{sup 99m} (DTPA) / Tc{sup 99m} (Mag3) and Tc{sup 99m} (Dmsa); Evaluacion de la dosis absorbida en los rinones debido al Tc{sup 99m} (DTPA) / Tc{sup 99m} (MAG3) y Tc{sup 99m} (DMSA)

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez A, M.; Murillo C, F.; Castillo D, C.; Rocha J, J.; Sifuentes D, Y.; Sanchez S, P. [Universidad Nacional de Trujillo, Av. Juan Pablo II s/n, Trujillo (Peru); Idrogo C, J.; Marquez P, F., E-mail: marvva@hotmail.com [Instituto Nacional de Enfermedades Neoplasicas, Av. Angamos 2520, Lima (Peru)

    2015-10-15

    The absorbed dose in the kidneys of adult patients has been assessed using the biokinetics of radiopharmaceuticals containing Tc{sup 99m} (DTPA) / Tc{sup 99m} (Mag3) or Tc{sup 99m} (Dmsa).The absorbed dose was calculated using the formalism MIRD and the Cristy-Eckerman representation for the kidneys. The absorbed dose to the kidneys due to Tc{sup 99m} (DTPA) / Tc{sup 99m} (Mag3), are given by 0.00466 mGy.MBq{sup -1} / 0.00339 mGy.MBq{sup -1}. Approximately 21.2% of the absorbed dose is due to the bladder (content) and the remaining tissue, included in biokinetics of Tc{sup 99m} (DTPA) / Tc{sup 99m} (Mag3). The absorbed dose to the kidneys due to Tc{sup 99m} (Dmsa) is 0.17881 mGy.MBq{sup -1}. Here, 1.7% of the absorbed dose is due to the bladder, spleen, liver and the remaining tissue, included in biokinetics of Tc{sup 99m} (Dmsa). (Author)

  9. Sustained availability of 99mTc: possible paths forward.

    Science.gov (United States)

    Pillai, Maroor Raghavan Ambikalmajan; Dash, Ashutosh; Knapp, F F Russ

    2013-02-01

    The availability of (99m)Tc for single-photon imaging in diagnostic nuclear medicine is crucial, and current availability is based on the (99)Mo/(99m)Tc generator fabricated from fission-based molybdenum (F (99)Mo) produced using high enriched uranium (HEU) targets. Because of risks related to nuclear material proliferation, the use of HEU targets is being phased out and alternative strategies for production of both (99)Mo and (99m)Tc are being evaluated intensely. There are evidently no plans for replacement of the limited number of reactors that have primarily provided most of the (99)Mo. The uninterrupted, dependable availability of (99m)Tc is a crucial issue. For these reasons, new options being pursued include both reactor- and accelerator-based strategies to sustain the continued availability of (99m)Tc without the use of HEU. In this paper, the scientific and economic issues for transitioning from HEU to non-HEU are also discussed. In addition, the comparative advantages, disadvantages, technical challenges, present status, future prospects, security concerns, economic viability, and regulatory obstacles are reviewed. The international actions in progress toward evolving possible alternative strategies to produce (99)Mo or (99m)Tc are analyzed as well. The breadth of technologies and new strategies under development to provide (99)Mo and (99m)Tc reflects both the broad interest in and the importance of the pivotal role of (99m)Tc in diagnostic nuclear medicine.

  10. Accumulation of 99m TC-methylene diphosphonate radiotracer in ...

    African Journals Online (AJOL)

    Accumulation of 99m TC-methylene diphosphonate radiotracer in rat's forelimb. ... by gamma camera 2 h after the injection of 99mTc-MDP via the tail vein. ... can be used for survey radioactivity examination in different bones of the forelimb.

  11. Electron Spin Pairing in High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    郭卫; 韩汝珊

    2001-01-01

    An electron pairing theory based on effective electron spin coupling mediated by antiferromagnetically correlated local moments is presented to account for high-Tc phenomena. We show that Kondo scattering and the suppression of the antiferromagnetic superexchange between Cu2+ moments lead to local triplet pairing, the mechanism underlying high-Tc superconductivity.

  12. Theoretical Modeling of 99 Tc NMR Chemical Shifts

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B.; Andersen, Amity; Washton, Nancy M.; Chatterjee, Sayandev; Levitskaia, Tatiana G.

    2016-09-06

    Technetium (Tc) displays a rich chemistry due to the wide range of oxidation states (from -I to +VII) and ability to form coordination compounds. Determination of Tc speciation in complex mixtures is a major challenge, and 99Tc NMR spec-troscopy is widely used to probe chemical environments of Tc in odd oxidation states. However interpretation of the 99Tc NMR data is hindered by the lack of reference compounds. DFT computations can help fill this gap, but to date few com-putational studies have focused on 99Tc NMR of compounds and complexes. This work systematically evaluates the inclu-sion small percentages of Hartree-Fock exchange correlation and relativistic effects in DFT computations to support in-terpretation of the 99Tc NMR spectra. Hybrid functionals are found to perform better than their pure GGA counterparts, and non-relativistic calculations have been found to generally show a lower mean absolute deviation from experiment. Overall non-relativistic PBE0 and B3PW91 calculations are found to most accurately predict 99Tc NMR chemical shifts.

  13. Muscle localization of Tc-99m MDP after exertion

    Energy Technology Data Exchange (ETDEWEB)

    Valk, P.

    1984-09-01

    Very high muscle uptake of Tc-99m MDP was seen two days after the start of a program of vigorous weight-lifting exercises. Localization of Tc-99m bone tracer in muscle that has been damaged by exertion may be a more common phenomenon than is recognized at present.

  14. An evidence of trap activation for positive temperature coefficient of resistivity in BaTiO3 ceramics with substitutional Nb and Mn as impurities

    Science.gov (United States)

    Miki, Toshikatsu; Fujimoto, Akira; Jida, Shin'suke

    1998-02-01

    The mechanism of the electrical resistivity increase above the Curie temperature TC [so-called positive temperature coefficient of resistivity (PTCR) effect] in BaTi1-x-yNbxMnyO3 ceramics is studied with the temperature-dependent resistivity and electron paramagnetic resonance (EPR) data and the calculated energy levels of various Mn-associated centers. The activation energy of trapped electrons at grain boundary interface states is deduced from the resistivity data. The deduced value is found to be nearly equal to the activation energy of Mn2+ and/or singlet EPR signals. This indicates that the EPR signals arising at the cubic phase are due to trapped-electron centers at grain boundaries, and that the centers responsible for the EPR signals contribute to the rise of grain boundary barrier above TC. The PTCR mechanism is separately discussed for mode I of abrupt resistivity jump at TC and mode II of moderate resistivity increase at higher temperatures. From the analyses of resistivity and EPR data, we found that mode II PTCR is well explained by the Heywang model, but mode I PTCR is hardly explained only by the effect of spontaneous polarization proposed by Jonker. Defect models of Mn-VO, Mn-VO-Mn, and Mn-O-Nb-VO type are proposed for Mn associated centers and VBa-VO or VO-VTi-VO type for cation-vacancy-associated centers, taking the local electroneutrality requirement for stable defects and the electronic energy change of substitutional Mn by phase transitions into account. Changes of the electronic energy levels of such defects by phase transitions successfully explain not only the PTCR and EPR data but also the degraded PTCR by incomplete or overabundant oxidation. A part of the Mn-VO centers formed at low Mn contents release electrons at the tetragonal phase forming Mn3+-VO with an effective charge of +1 to act as a charge compensator for negatively charged acceptors at the grain boundary, but the Mn-VO centers hardly act as acceptor-type electron

  15. A Comparative Study of 99mTc-YIGSR and 99mTc-MIBI Uptake in Tumor Cells

    Institute of Scientific and Technical Information of China (English)

    HU Jia; LAN Xiaoli; ZHANG Yongxue; GAO Zairong; WU Jun

    2005-01-01

    To investigate a new kind of tumor tracer 99mTc-YIGSR developed from a five amino structure (YIGSR) of the Laminin -chain,which can bind to the laminin receptors of tumor specifically, and radiolabeled with MAG3. (1) Preparation of the 99m Tc-YIGSR probe: with S-Acetly-NH3-MAG3as the chelator and with proper reductants YIGSR was labeled with 99mTc; (2) Cell culture and viability measurement: EAC was maintained in RPMI 1640 supplemented with calf serum; the trypan blue exclusion was applied to calculate the cell viability; (3) Study of the cell dynamic: The EACs uptake of 99mTc-YIGSR and99mTc-MIBI was observed at 37 ℃ and 22 ℃, respectively. (1)The labeling efficiencies of 99mTc-YIGSR and99mTc-MIBI were (62±3) % and (96±2) %, respectively; (2) The cell viability was declined with time of incubation; (3) At 37 ℃, the EACS uptake of 99mTc-YIGSR and99mTc-MIBI reached the peak of (43. 16±2.4) % and (24.4±1.8) % at 60min, respectively; and at 22 ℃, the highest uptake was (26.5±2.1) % and (9. 47±1.9) % at 60min, respectively. The in vitro study suggests that 99mTc-YIGSR is superior to 99mTc-MIBI in cell uptake and has potential value in tumor imaging.

  16. Experimental evidence of Tc enhancement without the influence of spin fluctuations: NMR study on LaFeAsO1 -xHx under a pressure of 3.0 GPa

    Science.gov (United States)

    Kawaguchi, N.; Fujiwara, N.; Iimura, S.; Matsuishi, S.; Hosono, H.

    2016-10-01

    The electron-doped high-transition-temperature (Tc) iron-based pnictide superconductor LaFeAsO1 -xHx has a unique phase diagram: Superconducting double domes are sandwiched by antiferromagnetic phases at ambient pressure and they turn into a single dome with a maximum Tc that exceeds 45 K at a pressure of 3.0 GPa. We studied whether spin fluctuations are involved in increasing Tc under a pressure of 3.0 GPa by using the 75As nuclear magnetic resonance (NMR) technique. The 75As-NMR results for the powder samples show that Tc increases up to 48 K without the influence of spin fluctuations. This fact indicates that spin fluctuations are not involved in raising Tc, which implies that other factors, such as orbital degrees of freedom, may be important for achieving a high Tc of almost 50 K.

  17. Comparison of relative renal function measured with either 99m Tc-DTPA or 99m Tc-EC dynamic scintigraphies with that measured with 99m Tc-DMSA static scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Domingues, F.C.; Fujikawa, G.Y.; Decker, H.; Alonso, G.; Pereira, J.C.; Duarte, P.S. [Centro de Diagnostico Fleury, Sao Paulo, SP (Brazil). Secao de Medicina Nuclear; Sao Paulo Univ. (USP), SP (Brazil). Escola de Saude Publica. Dept. de Epidemiologia]. E-mail: paulo.duarte@fleury.com.br

    2006-07-15

    Objective: The aim of this study was to compare the renal function measured with either {sup 99m}Tc-DTPA or {sup 99m}Tc-EC dynamic scintigraphies with that measured using {sup 99m}Tc-DMSA static scintigraphy. Methods: the values of relative renal function measured in 111 renal dynamic scintigraphies performed either with {sup 99m}Tc-DTPA (55 studies) or with {sup 99m}Tc-EC (56 studies) were compared with the relative function measured using {sup 99m}Tc-DMSA static scintigraphy performed within a 1-month period. The comparisons were performed using Wilcoxon signed rank test. The number of {sup 99m}Tc-DTPA and {sup 99m}Tc-EC studies that presented relative renal function different by more than 5% from that measured with {sup 99m}Tc-DMSA, using chi square test were also compared. Results: the relative renal function measured with {sup 99m}Tc-EC is not statistically different from that measured with {sup 99m}Tc-DMSA (p = 0.97). The relative renal function measured with {sup 99m}Tc-DTPA was statistically different from that measured using {sup 99m}Tc-DMSA, but with a borderline statistical significance (p = 0.05). The number of studies with relative renal function different by more than 5% from that measured with {sup 99m}Tc-DMSA is higher for the {sup 99m}Tc-DTPA scintigraphy (p 0.04) than for {sup 99m}Tc-EC. Conclusion: the relative renal function measured with {sup 99m}Tc-EC dynamic scintigraphy is comparable with that measured with {sup 99m}Tc-DMSA static scintigraphy, while the relative renal function measured with {sup 99m}Tc-DTPA dynamic scintigraphy presents a significant statistical difference from that measured with {sup 99m}Tc-DMSA static scintigraphy. (author)

  18. Comparison of relative renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured with 99mTc-DMSA static scintigraphy

    Directory of Open Access Journals (Sweden)

    F. C. Domingues

    2006-08-01

    Full Text Available OBJECTIVE: The aim of this study was to compare the renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured using 99mTc-DMSA static scintigraphy. METHODS: the values of relative renal function measured in 111 renal dynamic scintigraphies performed either with 99mTc-DTPA (55 studies or with 99mTc-EC (56 studies were compared with the relative function measured using 99mTc-DMSA static scintigraphy performed within a 1-month period. The comparisons were performed using Wilcoxon signed rank test. The number of 99mTc-DTPA and 99mTc-EC studies that presented relative renal function different by more than 5% from that measured with 99mTc-DMSA, using chi square test were also compared. RESULTS: the relative renal function measured with 99mTc-EC is not statistically different from that measured with 99mTc-DMSA (p = 0.97. The relative renal function measured with 99mTc-DTPA was statistically different from that measured using 99mTc-DMSA, but with a borderline statistical significance (p = 0.05. The number of studies with relative renal function different by more than 5% from that measured with 99mTc-DMSA is higher for the 99mTc-DTPA scintigraphy (p = 0.04 than for 99mTc-EC. CONCLUSION: the relative renal function measured with 99mTc-EC dynamic scintigraphy is comparable with that measured with 99mTc-DMSA static scintigraphy, while the relative renal function measured with 99mTc-DTPA dynamic scintigraphy presents a significant statistical difference from that measured with 99mTc-DMSA static scintigraphy.

  19. SrTcO3晶体结构和电子结构的第一性原理研究%The Crystal and Electronic Structures of SrTcO3 from First Principles

    Institute of Scientific and Technical Information of China (English)

    沈洁; 蔡田怡; 雎胜; 吴银忠

    2014-01-01

    Density-functional theory with generalized gradient approximation is applied to the study of the crys-tal and electronic properties of SrTcO3. The crystal structure is found to be orthorhombically distorted perovskite structure with space group Pnma, and the electronic structure is found to be insulating and G type antiferromag-netic, in which each Tc moment is antiparallel to its six nearest neighbours. A high Neel temperature of 948 K is predicted with the mean-field approximation because of the strong Tc 4d-O p hybridization and the large spa-tial extent of the 4d shells.%利用基于密度泛函的第一性原理计算方法,对钙钛矿型氧化物SrTcO3的基态晶体结构、电子结构、磁性质和尼尔温度进行计算。计算结果表明:SrTcO3的基态空间群是Pnma,晶体中氧八面体中心离子Tc在三维方向上都呈自旋反平行排列,是G类反铁磁绝缘体。 Tct2g-Op强烈的轨道杂化和Tc4d电子的巡游特性共同作用,导致SrTcO3具有948K的高尼尔温度。

  20. Radiolabeling of annexin A5 with {sup 99m}Tc: comparison of HYNIC-Tc vs. iminothiolane-Tc-tricarbonyl conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Biechlin, Marie-Laure [Faculte de Medecine Lyon-Sud (EA 3738), 69921 Oullins (France); Radiopharmacie, Centre Hospitalier de Chambery, 73000 Chambery (France)], E-mail: marie.laure.biechlin@ch-chambery.fr; Bonmartin, Alain; Gilly, Francois-Noel [Faculte de Medecine Lyon-Sud (EA 3738), 69921 Oullins (France); Fraysse, Marc [Radiopharmacie, Centre Hospitalier Lyon Sud, 69495 Pierre-Benite (France); Moulinet d' Hardemare, Amaury du [Departement de Chimie Moleculaire, Equipe de Chimie Inorganique Redox et Biomimetique, Universite Joseph Fourier-Grenoble I (DCM UMR 5250, ICMG), 38041 Grenoble cedex 9 (France)], E-mail: amaury.d-hardemare@ujf-grenoble.fr

    2008-08-15

    In the perspective of expanding the use of annexin A5 (anx A5) as radioactive tracer of cell death in vivo, we recently described its radiolabeling with {sup 99m}Tc-tricarbonyl [{sup 99m}Tc(H{sub 2}O){sub 3}(CO){sub 3}]{sup +} via the mercaptobutyrimidyl group (anx A5-SH). The aim of the present article was to compare this new method with the HYNIC strategy (anx A5-HYNIC), recognized at present as the reference for the radiolabeling of proteins with {sup 99m}Tc. Similar radiolabeling yields and better chemical stability were obtained with the [anx A5-SH-{sup 99m}Tc-tricarbonyl] complex. Since the [anx A5-HYNIC-{sup 99m}Tc(tricine){sub 2}] conjugate shows isomeric forms which can affect the biological properties whereas [anx A5-SH-{sup 99m}Tc-tricarbonyl] is less or not prone to such drawback, the latter seems superior to the former. Furthermore, (anx A5-SH) is readily obtained via commercial sources of Traut's reagent whereas (anx A5-HYNIC) is not. The results provide encouraging evidence in the development of anx A5-labeled reagent for apoptose imaging.

  1. Optimizing Tc in the (Mn,Cr,Ga)As and (Mn,Ga)(As,P) Ternary Alloys

    OpenAIRE

    Xu, J. L.; van Schilfgaarde, M.

    2005-01-01

    We explore two possible ways to enhance the critical temperature $T_c$ in the dilute magnetic semiconductor Mn$_{0.08}$Ga$_{0.92}$As. Within the context of the double-exchange and RKKY pictures, the ternary alloys Mn$_{x}$Cr$_{0.08-x}$Ga$_{0.92}$As and Mn$_{0.08}$Ga$_{0.92}$As$_y$P$_{1-y}$ might be expected to have $T_c$ higher than the pseudobinary Mn$_{0.08}$Ga$_{0.92}$As. To test whether the expectations from model pictures are confirmed, we employ linear response theory within the local-d...

  2. Nature of magnetic coupling between Mn ions in as-grown Ga$_{1-x}$Mn$_{x}$As studied by x-ray magnetic circular dichroism

    OpenAIRE

    Takeda, Y.; Kobayashi, M.; Okane, T.; Ohkochi, T.; Okamoto, J.; Saitoh, Y; Kobayashi, K.; Yamagami, H.; Fujimori, A.; Tanaka, A.; Okabayashi, J.; Oshima, M.; Ohya, S; Hai, P.N.; Tanaka, M.

    2008-01-01

    The magnetic properties of as-grown Ga$_{1-x}$Mn$_{x}$As have been investigated by the systematic measurements of temperature and magnetic field dependent soft x-ray magnetic circular dichroism (XMCD). The {\\it intrinsic} XMCD intensity at high temperatures obeys the Curie-Weiss law, but residual spin magnetic moment appears already around 100 K, significantly above Curie temperature ($T_C$), suggesting that short-range ferromagnetic correlations are developed above $T_C$. The present results...

  3. Doping effects of CuO additives on the properties of low-temperature-sintered PMnN-PZT-based piezoelectric ceramics and their applications on surface acoustic wave devices.

    Science.gov (United States)

    Tsai, Cheng-Che; Chu, Sheng-Yuan; Lu, Chun-Hsien

    2009-03-01

    To develop the anisotropic ceramic substrate with low sintering temperature for surface acoustic wave (SAW) applications, the low cost and feasible material with moderate piezoelectric properties, good dielectric properties, and higher Curie temperature were explored. The piezoelectric ceramics with compositions of Pb[(Mn(1/3)Nb(2/3))(0.06-) (Zr(0.52)Ti(0.48))0.94] O(3) (PMnN-PZT) + 0.5 wt.% PbO + x wt.% CuO (0.05 = x = 0.3) had been prepared by the conventional mixed-oxides method. CuO dopants were used as the sintering aid to improve the bulk density under low sintering temperature (i.e., 980-1040 degrees C). The phase structures, microstructures, frequency behavior of dielectric properties (up to 50 MHz), piezoelectric properties, ferroelectric properties, and temperature stability with the amount of CuO additive were systematically investigated. Experimental results showed that the sintering temperature could be lowered down to 1020 degrees C and still keep reasonably good piezoelectric activity (i.e., high electromechanical coupling factor (k(p)), (k(t)) and dielectric and ferroelectric properties. The preferable composition, obtained at x = 0.1, presented the values of the electromechanical coupling factor (k(p)) (k(t)), mechanical quality factor (Q(m)), piezoelectric charge constant (d(33)), dielectric constant, dielectric loss, temperature coefficient of resonant frequency (TCF(B)), and Curie point (T(c)) of 0.54, 0.48, 850, 238 pc/N, 1450, 0.0023, 1.1 kV/mm, 26 coul/cm(2), -150 ppm/ degrees C, and 348 degrees C. Using this developed low-temperature-sintered material to make the piezoelectric substrate, the SAW filter was fabricated and its properties were measured. Results showed that this device possessed very high value of k(2)(7.13%) with a good TCF (-40.15 ppm/ degrees C), and a surface wave velocity (V(P)) of 2196 m/s.

  4. Relaxation time of the Cooper pairs near Tc in cuprate superconductors

    Science.gov (United States)

    Ramallo, M. V.; Carballeira, C.; Viña, J.; Veira, J. A.; Mishonov, T.; Pavuna, D.; Vidal, F.

    1999-10-01

    It is first shown that the thermal fluctuation effects on the transport and on the thermodynamic observables above the superconducting transition may provide, when they are analyzed simultaneously and consistently, a powerful tool to access the relaxation time, τ0, of the Cooper pairs with wave vector k = 0 in high-temperature cuprate superconductors (HTSC). Then, we apply this procedure to optimally doped YBa2Cu3O7 - δ (Y-123) crystals. It is found that in this HTSC τ0 follows, within 20% accuracy, the BCS temperature behaviour and amplitude given by τ0 = πhbar/[8kB(T - Tc0)].

  5. Performance of TcI/TcVI/TcII Chagas-Flow ATE-IgG2a for universal and genotype-specific serodiagnosis of Trypanosoma cruzi infection

    Science.gov (United States)

    Alessio, Glaucia Diniz; de Araújo, Fernanda Fortes; Côrtes, Denise Fonseca; Sales Júnior, Policarpo Ademar; Lima, Daniela Cristina; Gomes, Matheus de Souza; do Amaral, Laurence Rodrigues; Xavier, Marcelo Antônio Pascoal; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; de Lana, Marta

    2017-01-01

    Distinct Trypanosoma cruzi genotypes have been considered relevant for patient management and therapeutic response of Chagas disease. However, typing strategies for genotype-specific serodiagnosis of Chagas disease are still unavailable and requires standardization for practical application. In this study, an innovative TcI/TcVI/TcII Chagas Flow ATE-IgG2a technique was developed with applicability for universal and genotype-specific diagnosis of T. cruzi infection. For this purpose, the reactivity of serum samples (percentage of positive fluorescent parasites-PPFP) obtained from mice chronically infected with TcI/Colombiana, TcVI/CL or TcII/Y strain as well as non-infected controls were determined using amastigote-AMA, trypomastigote-TRYPO and epimastigote-EPI in parallel batches of TcI, TcVI and TcII target antigens. Data demonstrated that “α-TcII-TRYPO/1:500, cut-off/PPFP = 20%” presented an excellent performance for universal diagnosis of T. cruzi infection (AUC = 1.0, Se and Sp = 100%). The combined set of attributes “α-TcI-TRYPO/1:4,000, cut-off/PPFP = 50%”, “α-TcII-AMA/1:1,000, cut-off/PPFP = 40%” and “α-TcVI-EPI/1:1,000, cut-off/PPFP = 45%” showed good performance to segregate infections with TcI/Colombiana, TcVI/CL or TcII/Y strain. Overall, hosts infected with TcI/Colombiana and TcII/Y strains displayed opposite patterns of reactivity with “α-TcI TRYPO” and “α-TcII AMA”. Hosts infected with TcVI/CL strain showed a typical interweaved distribution pattern. The method presented a good performance for genotype-specific diagnosis, with global accuracy of 69% when the population/prototype scenario include TcI, TcVI and TcII infections and 94% when comprise only TcI and TcII infections. This study also proposes a receiver operating reactivity panel, providing a feasible tool to classify serum samples from hosts infected with distinct T. cruzi genotypes, supporting the potential of this method for universal and genotype

  6. The Effect of Firing Temperatures on Phase Evolution, Microstructure, and Electrical Properties of Ba(Zr0.05Ti0.95O3 Ceramics Prepared via Combustion Technique

    Directory of Open Access Journals (Sweden)

    Chittakorn KORNPHOM

    2014-12-01

    Full Text Available In this work, the effects of calcination temperature (900 ºC – 1200 ºC for 2 h – 6 h and sintering temperature (1350 ºC – 1550 ºC for 2 h on phase evolution, microstructure and electrical properties of barium zirconate titanate Ba(Zr0.05Ti0.95O3 (BZT ceramics fabricated through the combustion technique were investigated. Glycine was used as fuel to reduce the reaction temperature. It was found that a single perovskite phase of BZT powders was observed from the sample calcined at 925 ºC for 6 h, which was lower than the solid state reaction technique ~275 ºC. The purity phase of an orthorhombic structure was observed in all ceramic samples. The average particle size (190 nm – 420 nm and the average grain size (2.9 mm – 41.4 mm increased with increased firing temperatures. The maximum theoretical density of ~96.8 % was obtained from the sample sintered at 1450 ºC for 2 h. The dielectric constant at room temperature (Tr and the dielectric constant at Curie temperature (Tc increased with increased sintering temperatures up to 1450 ºC and decreased thereafter. The dielectric properties corresponded to the obtained densities. The remnant polarization (Pr of the BZT ceramic (using the coercive electric field of 20 kV/cm increased with increasing sintering temperature. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6436

  7. Quantum and superconducting fluctuations effects in disordered Nb 1- xTa x thin films above Tc

    Science.gov (United States)

    Giannouri, M.; Papastaikoudis, C.

    1999-05-01

    Disordered Nb 1- xTa x thin films are prepared with e-gun coevaporation. The influence of the β-phase of tantalum in the critical temperature Tc is observed as a function of the substrate temperature. The measurements of transverse magnetoresistance at various isothermals are interpreted in terms of weak-localization and superconducting fluctuations. From the fitting procedure, the phase breaking rate τφ-1 and the Larkin parameter βL are estimated as a function of temperature. Conclusions about the dominant inelastic scattering mechanisms at various temperature regions as well as for the dominant mechanism of superconducting fluctuations near the transition temperature are extracted.

  8. Critical currents and superconductivity ferromagnetism coexistence in high-Tc oxides

    CERN Document Server

    Khene, Samir

    2016-01-01

    The book comprises six chapters which deal with the critical currents and the ferromagnetism-superconductivity coexistence in high-Tc oxides. It begins by gathering key data for superconducting state and the fundamental properties of the conventional superconductors, followed by a recap of the basic theories of superconductivity. It then discusses the differences introduced by the structural anisotropy on the Ginzburg-Landau approach and the Lawrence-Doniach model before addressing the dynamics of vortices and the ferromagnetism-superconductivity coexistence in high-Tc oxides, and provides an outline of the pinning phenomena of vortices in these materials, in particular the pinning of vortices by the spins. It elucidates the methods to improve the properties of superconducting materials for industrial applications. This optimization aims at obtaining critical temperatures and densities of critical currents at the maximum level possible. Whereas the primary objective is the basic mechanisms pushing the superco...

  9. The Study on AC Susceptibility Grained Model for The High-Tc Superconductor Bi-2223

    Science.gov (United States)

    Ozogul, O.

    2010-01-01

    The magnetic properties and the current transport of High-Tc ceramics are governed not only by the nature of diamagnetic grains but also by their interconnections which constitute the superconducting matrix. Such a sintered High-Tc Superconductor has two effects. One is intrinsic to the superconducting grains and the other is characteristic of the coupling between grains. These phenomena have been widely studied in order to understand the mechanisms governing the flux lines dynamic within critical-state models. While the original Bean model of the critical-state only predicts single characteristic in the imaginary part of the fundamental susceptibilities, grained Bean model, where the superconducting grains are immersed in weak superconducting matrix, predicts the typical double peak appear in the imaginary part and double transitions in the real part. The predictions of the grained Bean model for the field and temperature dependencies of the ac magnetic susceptibilities are compared with experimental results.

  10. Charmonium correlation and spectral functions at finite temperature

    CERN Document Server

    Ding, H -T; Kaczmarek, O; Karsch, F; Satz, H; Soeldner, W

    2010-01-01

    We study the properties of charmonium states at finite temperature in quenched QCD on isotropic lattices. We measured charmonium correlators using non-perturbatively $\\cO(a)$ improved clover fermions on fine ($a=0.01$ fm) lattices with a relatively large size of $128^{3}\\times 96$, $128^3\\times48$, $128^3\\times32$ and $128^3\\times24$ at $0.73~T_c$, $1.46~T_c$, $2.20~T_c$ and $2.93~T_c$, respectively. Our analysis suggests that $\\Jpsi$ is melted already at $1.46~T_c$ and $\\eta_c$ starts to dissolve at $1.46~T_c$ and does not exist at higher temperatures. We also identify the heavy quark transport contribution at the spectral function level for the first time.

  11. IsoNose - Isotopic Tools as Novel Sensors of Earth Surfaces Resources - A new Marie Curie Initial Training Network

    Science.gov (United States)

    von Blanckenburg, Friedhelm; Bouchez, Julien; Bouman, Caludia; Kamber, Balz; Gaillardet, Jérôme; Gorbushina, Anna; James, Rachael; Oelkers, Eric; Tesmer, Maja; Ashton, John

    2015-04-01

    The Marie Curie Initial Training Network »Isotopic Tools as Novel Sensors of Earth Surfaces Resources - IsoNose« is an alliance of eight international partners and five associated partners from science and industry. The project is coordinated at the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences and will run until February 2018. In the last 15 years advances in novel mass-spectrometric methods have opened opportunities to identify "isotopic fingerprints" of virtually all metals and to make use of the complete information contained in these fingerprints. The understanding developed with these new tools will ultimately guide the exploitation of Earth surface environments. However, progress in bringing these methods to end-users depends on a multi transfer of knowledge between (1) isotope Geochemistry and Microbiology, Environmental Sciences (2), Economic Geology and (3) instrument developers and users in the development of user-friendly and new mass spectrometric methods. IsoNose will focus on three major Earth surface resources: soil, water and metals. These resources are currently being exploited to an unprecedented extent and their efficient management is essential for future sustainable development. Novel stable isotope techniques will disclose the processes generating (e.g. weathering, mineral ore formation) and destroying (e.g. erosion, pollution) these resources. Within this field the following questions will be addressed and answered: - How do novel stable isotope signatures characterize weathering processes? - How do novel stable isotope signatures trace water transport? - How to use novel stable isotope as environmental tracers? - How to use novel stable isotope for detecting and exploring metal ores? - How to improve analytical capabilities and develop robust routine applications for novel stable isotopes? Starting from the central questions mentioned above the IsoNose activities are organized in five scientific work packages: 1

  12. Management of malignant phyllode tumors of the breast: the experience of the Institut Curie; Prise en charge des tumeurs phyllodes malignes du sein: l'experience de l'Institut Curie

    Energy Technology Data Exchange (ETDEWEB)

    Haberer, S.; Kirova, Y.M.; Dendale, R.; Campana, F.; Miranda, O.; Fourquet, A.; Bollet, M.A. [Institut Curie, Dept. de Radiotherapie Oncologique, 75 - Paris (France); Lae, M. [Institut Curie, Dept. de Biologie des Tumeurs, 75 - Paris (France); Seegers, V. [Institut Curie, Dept. de Biostatistiques, 75 - Paris (France); Pierga, J.Y. [Institut Curie, Dept. d' Oncologie Medicale, 75 - Paris (France); Salmon, R.; Reyal, F. [Institut Curie, Dept. de Chirurgie, 75 - Paris (France)

    2009-07-15

    Purpose Given the scarcity of malignant phyllode tumours of the breast and the absence of consensus regarding their management justify the need for institutional retrospective evaluations of clinical practices. Patients and methods Retrospective study with central pathology review of the 25 consecutive patients treated at the Institut Curie (Paris, France) between 1969 and 2006 for non metastatic malignant phyllodes tumors of the breast. The median follow-up was 65 months (7-257 months). Results Median age at diagnosis was 52 years (20-64 years). Breast surgery was conservative in five patients (20%). Surgical margins were wide (> 10 mm), narrow, involved or unknown in respectively 17 (68%), three (12%), three (12%) and two (8%) patients. Median tumour size was 65 mm (12-250 mm). Adjuvant radiotherapy was delivered in seven (28%) patients (two patients, post tumor-ectomy; five patients, post mastectomy) and 13 patients (52%) received anthracycline-based adjuvant chemotherapy. Five-year overall survival rate was 91% (95% CI, 80-100%). Five patients (20%) developed distant metastases (one after chemotherapy) and three (12%) locoregional relapse (one after tumor-ectomy and unknown margin without radiotherapy, two after mastectomy and involved margins with radiotherapy). Conclusion Wide breast surgery (that can be conservative in selected patients) is the mainstay of the treatment of non metastatic malignant phyllodes tumors of the breast. To better determine the respective roles of adjuvant systemic treatment and radiotherapy, further clinical studies and the search for new prognostic and predictive factors remain necessary. (authors)

  13. Oxygen Adsorption-Desorption Behavior and Superconducting Properties of High-Tc Bi(Pb)-Sr-Ca-Cu-O

    Science.gov (United States)

    Miura, Norio; Suzuta, Hiroki; Deshimaru, Yuichi; Shimizu, Youichi; Sakashita, Hirofumi; Yamazoe, Noboru

    1989-07-01

    Temperature-programmed desorption (TPD) chromatograms revealed that a small amount of oxygen was desorbed from high-Tc Bi(Pb)-Sr-Ca-Cu-O (BPSCCO) in the temperature range from ca. 350 to ca. 650°C prior to a steep increase of oxygen desorption in the higher temperature range. The Tc of BPSCCO was significantly lowered with the progress of oxygen desorption especially in the former temperature range, and was restored to the original level when the desorbed oxygen was recovered. With no corresponding changes in X-ray powder diffraction pattern being detected, the oxygen desorbed below ca. 650°C was concluded to have strong relevance to the superconductivity of BPSCCO.

  14. Sub-Tc electron transfer at the Hg-HTSC/liquid-electrolyte interface.

    Science.gov (United States)

    Green, Stephen J; Le-Poul, Nicolas; Edwards, Peter P; Peacock, Graeme

    2003-04-02

    The cyclic voltammetry of ferrocene (CpFeCp) adsorbed as a monolayer of CpFeCpCO2(CH2)8SH, self-assembled onto the Hg-based high-temperature superconductor Hg0.8Re0.2Ba2Ca2Cu3O10 (Tc = 134 K), via an ultrathin (3.1 nm) Ag film, has been performed in liquid electrolyte (16:7:1 EtCl/THF/2-MeTHF; 0.2 M LiBF4) at a range of temperatures spanning the superconducting transition. Kinetic analysis based on the Marcus density-of-states theory affords standard heterogeneous rate constants, k degrees , for the ferrocene/ferricinium electron-transfer reaction. Casting these data in Arrhenius form yields a value of k degrees (273 K) = 357 s-1, which is 10-fold lower than that previously reported for the same reaction at a metal electrode in a similar electrolyte, while the reorganizational energy of 0.92 eV for the superconductor interface is very close to that for the related metal interface of 0.95 eV. There is, however, no effect of the onset of superconductivity on the electron-transfer rate for this system; the Arrhenius plot is linear through Tc. This is the first sub-Tc electrochemistry of any kind on a Hg-based superconductor and demonstrates the ease with which kinetic data can be obtained for these very high-Tc materials, opening the way for the routine study of a range of electron-transfer reactions as novel probes of the superconducting state.

  15. Experimental Investigation and Numerical Simulation of the Grain Size Evolution during Isothermal Forging of a TC6 Alloy

    Institute of Scientific and Technical Information of China (English)

    Miaoquan LI; Shankun XUE; Aiming XIONG; Shenghui CHEN

    2005-01-01

    Hot compression was conducted at a Thermecmaster-Z simulator, at deformation temperatures of 800~1040℃, with strain rates of 0.001~50 s-1 and height reduction of 50%. Grain size of the prior α phase was measured with a Leica LABOR-LUX12MFS/ST microscope to which QUANTIMET 500 software for image analysis for quantitative metallography was linked. According to the present experimental data, a constitutive relationship for a TC6 alloy and a model for grain size of the prior α phase were established based on the Arrhenius' equation and the Yada's equation,respectively. By finite element (FE) simulation, deformation distribution was determined for isothermal forging of a TC6 aerofoil blade at temperatures of 860~940℃ and hammer velocities of 9~3000.0 mm/min. Meanwhile, the grain size of the prior α phase is simulated during isothermal forging of the TC6 aerofoil blade, by combining FE outputs with the present grain size model. The present results illustrate the grain size and its distribution in the prior α phase during the isothermal forging of the TC6 aerofoil blade. The simulated results show that the height reduction, deformation temperature, and hammer velocity have significant effects on distribution of the equivalent strain and the grain size of the prior α phase.

  16. Stepping outside the neighborhood of $T_c$ at LHC

    CERN Document Server

    Wiedemann, Urs Achim

    2009-01-01

    "As you are well aware, many in the RHIC community are interested in the LHC heavy-ion program, but have several questions: What can we learn at the LHC that is qualitatively new? Are collisions at LHC similar to RHIC ones, just with a somewhat hotter/denser initial state? If not, why not? These questions are asked in good faith, and this talk is an opportunity to answer them directly to much of the RHIC community." With these words, the organizers of Quark Matter 2009 in Knoxville invited me to discuss the physics opportunities for heavy ion collisions at the LHC without recalling the standard arguments, which are mainly based on the extended kinematic reach of the machine. In response, I emphasize here that lattice QCD indicates characteristic qualitative differences between thermal physics in the neighborhood of the critical temperature (T_c 400-500 MeV), for which the relevant energy densities will be solely attainable at the LHC.

  17. {sup 99m}Tc-sestamibi. Clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Bucerius, Jan [Maastricht Univ. Medical Center (Netherlands). Dept. of Nuclear Medicine and Cardiovascular Research Institute Maastricht; Ahmadzadehfar, Hojjat; Biersack, Hans-Juergen (eds.) [Universitaetsklinikum Bonn (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    2012-07-01

    {sup 99m}Tc-sestamibi is a single-photon emission computed tomography (SPECT) radiotracer that was introduced into clinical routine for myocardial perfusion imaging more than two decades ago. Although today the main application of {sup 99m}Tc-sestamibi SPECT remains the imaging of myocardial perfusion, it is also an accepted and well-proven imaging technique for a variety of oncologic and non-oncologic applications, including brain, breast, and thyroid cancer and thyroid and parathyroid adenoma. Its efficacy in a range of indications ensures that {sup 99m}Tc-sestamibi SPECT will remain widely used despite the rapid diffusion of 18F-FDG PET. {sup 99m}Tc-Sestamibi - Clinical Applications provides a detailed and informative overview of almost all the oncologic and non-oncologic applications of {sup 99m}Tc-sestamibi SPECT, including several relatively rare indications. Different disease-related protocols for {sup 99m}Tc-sestamibi SPECT are presented, and for each disease a comprehensive summary of the relevant pathology and epidemiology is provided. Throughout, there is a strong emphasis on the practical aspects of use of this popular tracer, including instructions for the preparation of several commercially available tracer kits. Clinical practitioners will find this book to be an invaluable guide to the application and benefits of {sup 99m}Tc-sestamibi SPECT in both the inpatient and the outpatient setting. (orig.)

  18. Tc-99m Ciprofloxacin SPECT of Pulmonary Tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Kyung; Hwang, Kyung Hoon [Gachon University Gil Hospital, Incheon (Korea, Republic of); Yoon, Min Ki [Good Samaritan Hospital, Pohang (Korea, Republic of); Choe, Won Sick [Kangbuk Samsung Hospital, Seoul (Korea, Republic of)

    2010-06-15

    Tc-99m ciprofloxacin is available for imaging infection. However, there has been no study on employing single photon emission computed tomography (SPECT) with using Tc-99m ciprofloxacin to image active pulmonary tuberculosis. Therefore, we conducted this study to assess the efficacy of Tc-99m ciprofloxacin SPECT for imaging active pulmonary tuberculosis. Twenty-one participants were enrolled in this prospective study. They were divided into two groups according to the clinical and radiological assessment. Group one (Gr. 1) consisted of five normal volunteers and six patients with inactive pulmonary tuberculosis. Group two (Gr. 2) consisted of ten patients with active pulmonary tuberculosis. SPECT was performed 3 h after injecting 555 MBq (15 mCi) of Tc-99m ciprofloxacin. The findings of Tc-99m ciprofloxacin SPECT were interpreted by a nuclear medicine specialist and then the results were analyzed according to the patients' clinical and radiological classifications. The results of Tc-99m ciprofloxacin SPECT were as follows: eight true-positive cases, ten true-negative cases, one false-positive case and two false-negative cases. The sensitivity and specificity was 80.0% and 90.0%, respectively. The positive predictive value was 88.9% and the negative predictive value was 83.3%. Conclusions Tc-99m ciprofloxacin SPECT is feasible for imaging active pulmonary tuberculosis. It is a useful nuclear-imaging method for discriminating between the active and inactive tuberculosis states in patients with a past medical history of pulmonary tuberculosis.

  19. Structural and phase transformations in the low-temperature annealed amorphous “finemet”-type microwires

    Energy Technology Data Exchange (ETDEWEB)

    Tcherdyntsev, V.V., E-mail: vvch08@yandex.ru [National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Aleev, A.A. [SSC RF Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); Churyukanova, M.N.; Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Medvedeva, E.V. [Institute of Electrophysics, Ural Branch, Russian Academy of Sciences, Yekaterinburg 620016 (Russian Federation); Korchuganova, O.A. [SSC RF Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); Zhukova, V. [Dpto. de Fns. Mater., UPV/EHU, San Sebastian 20018 (Spain); Zhukov, A.P. [Dpto. de Fns. Mater., UPV/EHU, San Sebastian 20018 (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

    2014-02-15

    Highlights: • Structure and magnetic properties evolution at heating of amorphous microwires was studied. • Relaxation processes in the amorphous phase correlate with an increase in Curie temperature. • Curie temperature change can not be stabilized by a prolonged exposure at pre-crystallization temperatures. • Tomographic atom probe microscopy supports the formation of α-Fe phase precipitations enriched in Si. -- Abstract: Finemet-type glass-coated microwires with amorphous and nanocrystalline structure have been investigated. The relaxation and crystallization processes at heating of amorphous alloy have been studied by DSC method. We observed that the relaxation processes in the amorphous phase correlate with an increasing of the Curie temperature. Additionally a prolonged exposure of the samples below the crystallization temperatures does not stabilize the Curie temperature change. An investigation by the tomographic atom probe microscopy supports the formation of precipitations, probably α-Fe phase, as a result of low-temperature annealing (400 °C, 5 min). We found that the observed nano-sized areas were enriched in silicon.

  20. Analysis of Magnetic Critical Fields in Iron-Based SmFeAsO0.85 HIGH-Tc Superconductor

    Science.gov (United States)

    Ahmad, Dawood; Song, Tae Kwon; Park, In Suk; Kim, G. C.; Ren, Zhi-An; Kim, Y. C.

    The magnetic properties of the newly discovered iron-oxypnictide SmFeAsO0.85 high-Tc superconductor with a Tc of around 55 K were investigated. Bulk SmFeAsO0.85 was prepared by a method for high-pressure synthesis. The lower critical field Hc1 was estimated from the magnetization at low fields; Hc1(0) was measured to be 212 Oe. A linear temperature dependence instead of saturation at low temperatures in Hc1(T) revealed unconventional superconductivity with a nodal gap structure in our SmFeAsO0.85 superconductor. The results showed that the well-known secondary peak in the temperature dependence of the critical current density Jc is absent in the SmFeAsO0.85 high-Tc superconductor. The irreversibility line Birr was fitted well by the power law dependence (1 - T/Tc)n with n ~ 1.5. This is indicative of the flux creep phenomena in the SmFeAsO0.85 high-Tc superconductor. In addition, within the range of measurement temperatures in this study, no crossover was observed in the temperature dependence of the irreversibility line Birr which may be due to low anisotropy in our SmFeAsO0.85 superconductor.

  1. Asialoglycoprotein receptor targeted imaging using Tc-99m galactosylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E. M.; Jeong, H. J.; Kim, B. C.; Kim, C. K [Wonkang University College of Medicine, Iksan (Korea, Republic of)

    2004-07-01

    The asialoglycoprotein receptor (ASGP-R) is expressed on liver hepatocytes. Chitosan conjugates of galactose have shown to be specifically taken up by liver parenchymal cells via ASGP-R. In this study, Tc-99m hydrazino nicotinamide (HYNIC)-galactosylated chitosan (HYNIC-GC) was synthesized and evaluated as a targeted agent for the imaging of hepatocytes. GC was obtained after coupling of lactobionic acid as the galactose moiety and coupled with HYNIC. HYNIC-GC was radiolabeled with Tc-99m using stannous chloride and tricine as reducing agent and coligand respectively. Hepatic uptake property of Tc-99m HYNIC-GC was studied in female Balb/C mouse. Tc-99m HYNIC--GC and Tc-99m HYNIC-Chitosan as a control were intravenously injected into mice. Receptor binding was identified by coinjection with 50 mM and 80mM free galactose respectively. Biodistribution was determined at three different time points. The level of galactose substitution was 7.6%. Labeling efficiency was >90% both in vitro and serum up to 24 h. Tc-99m HYNIC-GC injected via tail vein of mice showed high selectivity of liver. On the other hands, Tc-99m HC without galactose group showed low uptake (Fig. 1A, 1B). Hepatic uptake of Tc-99m HYNIC-GC was dramatically blocked by 50 mM and 80 mM free galactose coinjection (Fig. 1C, 1D). The liver accumulated about 14 percent injected dose per gram (%ID/g) up to 120 min after injection. Tc-99m HYNIC-GC showed specific and rapid targeting to liver. It is a promising specific radiopharmaceutical with potential applications in the imaging of liver parenchymal cells.

  2. Cr-Doped InAs Self-Organized Diluted Magnetic Quantum Dots with Room-Temperature Ferromagnetism

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yu-Hong; ZHAO Jian-Hua; BI Jing-Feng; WANG Wei-Zhu; JI Yang; WU Xiao-Guang; XIA Jian-Bai

    2007-01-01

    Cr-doped InAs self-organized diluted magnetic quantum dots (QDs) are grown by low-temperature molecularbeam epitaxy. Magnetic measurements reveal that the Curie temperature of all the InAs:Cr QDs layers with Cr/In flux ratio changing from 0.026 to 0.18 is beyond 400K. High-resolution cross sectional transmission electron microscopy images indicate that InAs:Cr QDs are of the zincblende structure. Possible origins responsible for the high Curie temperature are discussed.

  3. Attachment of Free Filament Thermocouples for Temperature Measurements on CMC

    Science.gov (United States)

    Lei, Jih-Fen; Cuy, Michael D.; Wnuk, Stephen P.

    1997-01-01

    Ceramic Matrix Composites (CMC) are being developed for use as enabling materials for advanced aeropropulsion engine and high speed civil transport applications. The characterization and testing of these advanced materials in hostile, high-temperature environments require accurate measurement of the material temperatures. Commonly used wire Thermo-Couples (TC) can not be attached to this ceramic based material via conventional spot-welding techniques. Attachment of wire TC's with commercially available ceramic cements fail to provide sufficient adhesion at high temperatures. While advanced thin film TC technology provides minimally intrusive surface temperature measurement and has good adhesion on the CMC, its fabrication requires sophisticated and expensive facilities and is very time consuming. In addition, the durability of lead wire attachments to both thin film TC's and the substrate materials requires further improvement. This paper presents a newly developed attachment technique for installation of free filament wire TC's with a unique convoluted design on ceramic based materials such as CMC's. Three CMC's (SiC/SiC CMC and alumina/alumina CMC) instrumented with type IC, R or S wire TC's were tested in a Mach 0.3 burner rig. The CMC temperatures measured from these wire TC's were compared to that from the facility pyrometer and thin film TC's. There was no sign of TC delamination even after several hours exposure to 1200 C. The test results proved that this new technique can successfully attach wire TC's on CMC's and provide temperature data in hostile environments. The sensor fabrication process is less expensive and requires very little time compared to that of the thin film TC's. The same installation technique/process can also be applied to attach lead wires for thin film sensor systems.

  4. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    Institute of Scientific and Technical Information of China (English)

    Lei Jin; Peizhong Li; Haibin Zhou; Wei Zhang; Guodong Zhou; Chun Wang

    2015-01-01

    In this paper, air plasmas spray (APS) was used to prepare YSZ and Sc2O3–YSZ (ScYSZ) coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2 aerogel are 0.553, 0.539 and 0.2097 ? 10 ? 6 m2/s, respectively. Then, the thermal insulation performances of three kinds of coating were investigated from 20 1C to 400 1C using high infrared radiation heat flux technology. The experimental results indicated that the corresponding temperature difference between the top TC4 alloy (400 1C) and the bottom surface of YSZ is 41.5 1C for 0.6 mm thickness coating. For 1 mm thickness coating, the corresponding temperature difference between the top TC4 alloys (400 1C) and the bottom surface of YSZ, ScYSZ, SiO2 aerogel three specimens is 54, 54.6 and 208 1C, respectively. The coating thickness and species were found to influence the heat insulation ability. In these materials, YSZ and ScYSZ exhibited a little difference for heat insulation behavior. However, SiO2 aerogel was the best one among them and it can be taken as protection material on TC4 alloys. In outer space, SiO2 aerogel can meet the need of thermal insulation of TC4 of high-speed aircraft.

  5. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    Directory of Open Access Journals (Sweden)

    Lei Jin

    2015-04-01

    Full Text Available In this paper, air plasmas spray (APS was used to prepare YSZ and Sc2O3–YSZ (ScYSZ coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2 aerogel are 0.553, 0.539 and 0.2097×10−6 m2/s, respectively. Then, the thermal insulation performances of three kinds of coating were investigated from 20 °C to 400 °C using high infrared radiation heat flux technology. The experimental results indicated that the corresponding temperature difference between the top TC4 alloy (400 °C and the bottom surface of YSZ is 41.5 °C for 0.6 mm thickness coating. For 1 mm thickness coating, the corresponding temperature difference between the top TC4 alloys (400 °C and the bottom surface of YSZ, ScYSZ, SiO2 aerogel three specimens is 54, 54.6 and 208 °C, respectively. The coating thickness and species were found to influence the heat insulation ability. In these materials, YSZ and ScYSZ exhibited a little difference for heat insulation behavior. However, SiO2 aerogel was the best one among them and it can be taken as protection material on TC4 alloys. In outer space, SiO2 aerogel can meet the need of thermal insulation of TC4 of high-speed aircraft.

  6. Introduction to the EC's Marie Curie Initial Training Network (MC-ITN) project: Particle Training Network for European Radiotherapy (PARTNER).

    Science.gov (United States)

    Dosanjh, Manjit; Magrin, Giulio

    2013-07-01

    PARTNER (Particle Training Network for European Radiotherapy) is a project funded by the European Commission's Marie Curie-ITN funding scheme through the ENLIGHT Platform for 5.6 million Euro. PARTNER has brought together academic institutes, research centres and leading European companies, focusing in particular on a specialized radiotherapy (RT) called hadron therapy (HT), interchangeably referred to as particle therapy (PT). The ultimate goal of HT is to deliver more effective treatment to cancer patients leading to major improvement in the health of citizens. In Europe, several hundred million Euro have been invested, since the beginning of this century, in PT. In this decade, the use of HT is rapidly growing across Europe, and there is an urgent need for qualified researchers from a range of disciplines to work on its translational research. In response to this need, the European community of HT, and in particular 10 leading academic institutes, research centres, companies and small and medium-sized enterprises, joined together to form the PARTNER consortium. All partners have international reputations in the diverse but complementary fields associated with PT: clinical, radiobiological and technological. Thus the network incorporates a unique set of competencies, expertise, infrastructures and training possibilities. This paper describes the status and needs of PT research in Europe, the importance of and challenges associated with the creation of a training network, the objectives, the initial results, and the expected long-term benefits of the PARTNER initiative.

  7. CIENTISTAS EM REVISTA: EINSTEIN, DARWIN E MARIE CURIE NA CIÊNCIA HOJE DAS CRIANÇAS

    Directory of Open Access Journals (Sweden)

    Sheila Alves de Almeida

    Full Text Available RESUMO: Este trabalho analisou três edições da revista Ciência Hoje das Crianças, em que Einstein, Darwin e Marie Curie são apresentados. Frente ao desafio de divulgar a vida e a obra desses cientistas de forma adequada às crianças, para análise dos artigos consideramos a linguagem utilizada, as imagens apresentadas e, principalmente, a representação da revista sobre os cientistas. A metodologia de análise do material é inspirada nos trabalhos de Bakhtin sobre dialogismo e na compreensão por meio dos procedimentos discursivos, verbais e visuais com que a revista interpela e dialoga com as crianças. Os resultados mostram que a chancela editorial opta por focar a infância dos cientistas e uma imagem do cientista curioso e aventureiro. Entretanto, veicula-se nos artigos analisados uma visão estereotipada do cientista como alguém que já se anunciava cientista. Reitera-se a importância da Ciência Hoje das Crianças para a promoção da leitura e a democratização da linguagem de divulgação científica para crianças.

  8. Large deviations of the finite-time magnetization of the Curie-Weiss random-field Ising model

    Science.gov (United States)

    Paga, Pierre; Kühn, Reimer

    2017-08-01

    We study the large deviations of the magnetization at some finite time in the Curie-Weiss random field Ising model with parallel updating. While relaxation dynamics in an infinite-time horizon gives rise to unique dynamical trajectories [specified by initial conditions and governed by first-order dynamics of the form mt +1=f (mt) ] , we observe that the introduction of a finite-time horizon and the specification of terminal conditions can generate a host of metastable solutions obeying second-order dynamics. We show that these solutions are governed by a Newtonian-like dynamics in discrete time which permits solutions in terms of both the first-order relaxation ("forward") dynamics and the backward dynamics mt +1=f-1(mt) . Our approach allows us to classify trajectories for a given final magnetization as stable or metastable according to the value of the rate function associated with them. We find that in analogy to the Freidlin-Wentzell description of the stochastic dynamics of escape from metastable states, the dominant trajectories may switch between the two types (forward and backward) of first-order dynamics. Additionally, we show how to compute rate functions when uncertainty in the quenched disorder is introduced.

  9. Measured Temperature Dependence of the cos-phi Conductance in Josephson Tunnel Junctions

    DEFF Research Database (Denmark)

    Sørensen, O. H.; Mygind, Jesper; Pedersen, Niels Falsig

    1977-01-01

    The temperature dependence of the cosϕ conductance in Sn-O-Sn Josephson tunnel junctions has been measured just below the critical temperature, Tc. From the resonant microwave response at the junction plasma frequency as the temperature is decreased from Tc it is deduced that the amplitude...

  10. Comments on photoelectron spectroscopy of high- Tc 's

    Energy Technology Data Exchange (ETDEWEB)

    Arko, A.J.

    1991-01-01

    The photoemission discussion session during the Argonne conference on Fermiology of High-{Tc}'s provided a forum to air a number of unresolved issues in photoelectron spectroscopy. These are: (a) what is the exact energy dependence of the line width of the quasiparticle peaks: (b) are there any chemical potential shifts with hole doping; (c) why is a superconducting gap not observed in Y-123; and (d) different groups report different results in the band structure of Bi-2212. The first issue, while much discussed, essentially becomes a non-issue in the sense that nearly all theories predict a linear as well as a quadratic energy dependence to the quasiparticle lifetime. Furthermore, the data are not yet good enough to distinguish between linear and quadratic dependence in the important region within 0.1 eV of E{sub F}. Regarding chemical potential shifts, they very definitely are observed with hole doping both in Y-123 and Bi-2212 in spite of the claims by RVB enthusiasts to the contrary. In Y-123 the shifts are as large as 0.75 eV. The non-observation of a gap in Y-123 is puzzling, but may be related to surface reconstruction and an overdoped situation. The important question of whether we have one or two bands near E{sub F} in Bi-2212 revolves around the surface quality of the samples studied by different groups. It is difficult to compare data taken at room temperature vs. data taken at low temperature when no documentation exists that a reconstruction did not occur. We suspect that the small second band championed by the Sendai group is a surface impurity band.

  11. Effect of multidrug resistance gene-1(mdr1) overexpression on in-vitro uptake of {sup 99m}Tc-sestaMIBI in murine L1210 leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kyung Ah; Lee, Jae Tae; Lee, Sang Woo; Kang, Do Young; Sohn, Snag Kyun; Lee, Jong Kee; Jun, Soo Han; Lee, Kyu Bo [College of Medicine, Kyungpook National Univ., Taegu (Korea, Republic of); Chung, June Key [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    1999-02-01

    To determine whether {sup 99m}Tc-MIBI is recognized by the multidrug resistant P-glycoprotein (Pgp), we have measured quantitatively {sup 99m}Tc-MIBI uptake in cancer cells. The effects of various Pgp reversing agents on cellular {sup 99m}Tc-MIBI uptake were also investigated in the presence of multidrug resistance gene-1 (mdr 1 gene) overexpression. We measured percentage uptake of {sup 99m}Tc-MIBI at different incubation temperatures both in mdr1 positive and negative cells. The effects of verapamil, cyclosporin, and dipyridamole on cellular uptake of {sup 99m}Tc-MIBI were also evaluated with or without overexpression of mdr1 gene in cultured murine leukemia L1210 cells. The mdr1 gene expressing cell lines were effectively induced in in vitro with continuous application of low-dose adriamycin or vincristine. Cellular uptake of {sup 99m}Tc-MIBI was higher in mdr1 negative L1210 cells than those of mdr1 positive cells, and higher when incubated in 37 .deg. C than 4 .deg. C. In the presence of verapamil, cyclosporin or dipyridamole, {sup 99m}Tc-MIBI uptake was increased upto 604% in mdr1 positive cells. Cellular uptake of {sup 99m}Tc-MIBI is lower in leukemia cells over-expressing mdr1 gene, and MDR-reversing agents increase cellular uptake. These results suggest the {sup 99m}Tc-MIBI can be used for characterizing Pgp expression and developing MDR-reversing agents in vitro.

  12. Thermophysical properties of Almahata Sitta meteorites (asteroid 2008 TC3) for high-fidelity entry modeling

    Science.gov (United States)

    Loehle, Stefan; Jenniskens, Peter; Böhrk, Hannah; Bauer, Thomas; Elsäßer, Henning; Sears, Derek W.; Zolensky, Michael E.; Shaddad, Muawia H.

    2017-02-01

    Asteroid 2008 TC3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high-fidelity re-entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation (T 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC3: a thick flat-faced ureilite suitably shaped for emissivity measurements and a thin flat-faced EL6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3-D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10-5 K-1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage.

  13. Computational Intelligence Approach for Estimating Superconducting Transition Temperature of Disordered MgB2 Superconductors Using Room Temperature Resistivity

    Directory of Open Access Journals (Sweden)

    Taoreed O. Owolabi

    2016-01-01

    Full Text Available Doping and fabrication conditions bring about disorder in MgB2 superconductor and further influence its room temperature resistivity as well as its superconducting transition temperature (TC. Existence of a model that directly estimates TC of any doped MgB2 superconductor from the room temperature resistivity would have immense significance since room temperature resistivity is easily measured using conventional resistivity measuring instrument and the experimental measurement of TC wastes valuable resources and is confined to low temperature regime. This work develops a model, superconducting transition temperature estimator (STTE, that directly estimates TC of disordered MgB2 superconductors using room temperature resistivity as input to the model. STTE was developed through training and testing support vector regression (SVR with ten experimental values of room temperature resistivity and their corresponding TC using the best performance parameters obtained through test-set cross validation optimization technique. The developed STTE was used to estimate TC of different disordered MgB2 superconductors and the obtained results show excellent agreement with the reported experimental data. STTE can therefore be incorporated into resistivity measuring instruments for quick and direct estimation of TC of disordered MgB2 superconductors with high degree of accuracy.

  14. Preparation of 99mTc-EDTA-MN and Its Bioimaging in Mouse

    Directory of Open Access Journals (Sweden)

    Yongshuai QI

    2015-07-01

    Full Text Available Background and objective Hypoxia is an important biological characteristics of solid tumor, it is not sensitive to radiotherapy and chemotherapy for which is the presence of hypoxic cell, thus increasing their resistance to conventional radiotherapy and chemotherapy, therefore, the detection of hypoxia degree of tumor tissue is of great significance. The hypoxia imaging of nuclear medicine can reflect the degree of tissue hypoxia, which can selectively retained on the hypoxic cells or tissues, including nitroimidazole and non nitroimidazole; the nitroimidazole is widely and deeply researched as hypoxic celles developer in China and abroad at present. The research about application of radionuclide labelled technique has clinical application value to develop the hypoxia imaging agent EDTA-MN complexes which was labeled. To study the feasibility of 99mTc by direct labeling method, the radiochemical properties evaluation of 99mTc-EDTA-MN, and observe the distribution characteristics of 99mTc radiolabeled EDTA-MN in the xenograft lung cancer nude mice bearing non-small cell lung cancer cell (A549, and provide experimental evidence for its further research and application. Methods The radiolabeling of EDTA-MN with 99mTc was performed with direct labeling method, respectively, on the reaction dosage (10 mg, 5 mg, 2 mg, stannous chloride dosage (8 mg/mL, 4 mg/mL, 2 mg/mL, mark system pH (2, 4, 5, 6 one by one test, using orthogonal design analysis, to find the optimal labeling conditions. Labelling rate, radiochemical purity, lipid-water partition coefficient and in vitro stability in normal saline (NS were determined by TLC and HPLC, and the preliminary study on the distribution of 99mTc-EDTA-MN in nude mice. Results The labeling rate of 99mTc-EDTA-MN with the best labeling conditions was (84.11±2.83%, and the radiochemical purity was higher than 90% by HPLC purification, without any notable decomposition at room temperature over a period of 12 h. The

  15. Beta decay of Tc-111 to Ru-111

    NARCIS (Netherlands)

    Pfeiffer, B; Lhersonneau, G; Dendooven, P; Honkanen, A; Huhta, M; Klockl, [No Value; Oinonen, M; Penttila, H; Persson, B.L.; Perajarvi, K; Wang, JC; Kratz, KL; Aysto, J

    1998-01-01

    The beta-decay of the very neutron-rich Tc-111 nucleus has been observed. A partial decay scheme of Ru-111 is presented, complementing the high-spin levels earlier reported in spontaneous fission work.

  16. NESDIS Microwave Sounder-based Tropical Cyclone (TC) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The S-NPP Microwave Sounder-based Tropical Cyclone (TC) Products provide estimates of tropical cyclone maximum wind speed, minimum sea level pressure, radii of 34,...

  17. Intra-arterial injection of Tc-99m MDP

    Directory of Open Access Journals (Sweden)

    Ebru Salmanoglu

    2016-03-01

    Full Text Available Bone scintigraphy is applied to evaluate abnormalities of axial skeleton and appendicular skeleton including osteomyelitis, prosthesis infection, prosthesis loosening, avascular necrosis, stress fracture, bone metastasis. Technetium-99m methylene diphosphonate (Tc-99m MDP is most common used radiopharmaceutical. Injection of Tc-99m MDP should be done intravenous but it can be done intra-arterial, accidentally. After intra-arterial injection of Tc-99m MDP, it cause prominent soft tissue uptake distal to the injection site. This situation can create confusion in the scintigraphic images. Usually, it imitate reflex sympathetic dystrophy, so differential diagnosis is important. The aim of this report is to present the appearance of inadvertent intra-arterial injection of Tc-99m MDP. [Cukurova Med J 2016; 41(0.100: 79-82

  18. Discordant results in Tc-99m tetrofosmin and Tc-99m sestamibi parathyroid scintigraphies; Resultados discordantes em cintilografias das paratireoides realizadas com tetrofosmin-99mTc e com sestamibi-99mTc

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Paulo Schiavom; Domingues, Fernanda C.; Santi Costa, Michele; Brandao, Cynthia; Oliveira, Marco A.C. de; Vieira, Jose G.H. [Fleury - Centro de Medicina Diagnostica, Sao Paulo, SP (Brazil)]. E-mail: paulo.duarte@fleury.com.br

    2007-10-15

    Parathyroid scintigraphies have been used to detect pathological parathyroid glands either before as well as after the parathyroid resection surgery in patients with hyperparathyroidism. One of the most utilized techniques to perform the studies is the double-phase images with Tc-99m sestamibi, which has been shown to be very accurate in the localization of enlarged parathyroid glands. Similar to Tc-99m sestamibi, Tc-99m tetrofosmin is a radiopharmaceutical initially developed to perform myocardial perfusion study that has been used to perform parathyroid scintigraphies. Although most of the papers suggest that the overall sensitivities of both radiopharmaceuticals are similar, there are some papers questioning the accuracy of Tc-99m tetrofosmin to detect abnormal parathyroid glands. In the present article, we report a case with discordant results by both methods. (author)

  19. Preoperative concomitant radio chemotherapy in bulky carcinoma of the cervix: Institut Curie experience; Chimioradiotherapie concomitante preoperatoire dans les carcinomes du col uterin de stades IB2 a IIB: experience de l'Institut Curie

    Energy Technology Data Exchange (ETDEWEB)

    Kirova, Y.M.; Bourhaleb, Z.; Campitelli, M.; De la Rochefordiere, A. [Institut Curie, Groupe de Gynecologie, Service d' Oncologie et de Radiotherapie, 75 - Paris (France); Alran, S.; Fourchotte, V. [Institut Curie, Groupe de Gynecologie, Service de Chirurgie, 75 - Paris (France); Plancher, C. [Institut Curie, Groupe de Gynecologie, Service de Biostatistique, 75 - Paris (France); Beuzeboc, P.; Cottu, P. [Institut Curie, Groupe de Gynecologie, Service d' Oncologie Medicale, 75 - Paris (France); Petrow, P. [Institut Curie, Groupe de Gynecologie, Service de Radiologie, 75 - Paris (France); Cremoux, P. de; Sastre-Garau, X. [Institut Curie, Groupe de Pathologie, Service de Radiologie, 75 - Paris (France)

    2009-07-15

    Purpose: To evaluate the treatment results of patients (pts) with Figo stage IB2, IIA, IIB cervical carcinoma (C.C.) treated with preoperative radio chemotherapy, followed by extended radical hysterectomy. Patients and methods: Retrospective study of 148 women treated to the Curie Institute for operable Figo Stage IB2 to IIB, biopsy proved C.C.. Among them, 70 pts, median age 46 years, were treated using the same regimen associating primary radio cis-platinum based chemotherapy,intracavitary LDR brachytherapy, followed by extended radical hysterectomy. Kaplan-Meier estimates were used to draw survival curves. Comparisons of survival distribution were assessed by the log-rank test. Results: Complete histological local-regional response was obtained in 56% of the pts (n = 39). Residual macroscopic or microscopic disease in the cervix was observed in 28 pts (40%). All but one had in situ microscopic residual C.C.. Lateral residual disease in the parametria was also present in nine pts, all with residual C.C.. Pelvic lymph nodes were free from microscopic disease in 56 pts (80%). Eight of 55 (11%) radiological N0 patients had microscopic nodal involvement, as compared to 6/15 (40%) radiological N1 (p = 0.03). Seventeen pts (25%) had residual cervix disease but negative nodes. After median follow-up of 40 months (range, 8-141), 38/70 patients (54.1%) are still alive and free of disease, six (8.6%) alive with disease, and 11 (15.8%) patients were lost for follow-up but free of disease. Conclusion: The treatment of locally advanced C.C. needs a new multidisciplinary diagnostic and treatment approach using new therapeutic arms to improve the survival and treatment tolerance among women presenting this disease. (authors)

  20. Representation of A15 composition and TC in internal-Sn Nb3Sn superconducting strands

    Institute of Scientific and Technical Information of China (English)

    Andre; SULPICE; Jean-Louis; SOUBEYROUX; Christophe; VERWAERDE; Gia; Ky; HOANG

    2010-01-01

    Four sets of mono-element (ME) and two kinds of multifilament (MF) internal-Sn Nb3Sn superconducting strands were designed and fabricated through RRP method in which different compoment ratios, various composite configurations and some third element alloying were arranged. All the strand samples underwent a 210°C/50 h + 340°C/25 h thermal duration for Cu-Sn alloying. After that A15 phase formation heat treatment (HT) was applied for which the ME samples were chosen at three reaction temperatures of 675°C, 700°C and 725°C for 100 h and 200 h while the MF samples at four temperatures of 650°C, 675°C, 700°C and 725°C for 128 h and 200 h. The heat-treated samples were examined for A15 phase composition distribution by X-ray EDS. SQUID magnetization measurement was used to determine critical temperature TC. The obtained results demonstrate that for fully-reacted internal-Sn Nb3Sn superconductors the A15 phase composition and the intrinsic property TC are determined by the diffusion and solid state reaction mechanism and are independent of the factors including HT temperature, strand composite component and configuration arrangement, and the third element addition within the experimental range.

  1. Sorption, Desorption and Diffusion of Tc Under Anaerobic Conditions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The sorption and diffusion of Tc on granite under anaerobic conditions were investigated. Influencesof pH values, ferrous minerals(reduced iron powder or magnetite), bentonite, concentration of cations andanion (Fe3+, Fe2+ and CO32-) on the distribution coefficient, Kd, were studied. The sorption mechanism of99Tc on granite was analyzed by the desorption method of adding H2O2 into desorption solvent. Based on

  2. Availability of {sup 99}Tc in undisturbed soil cores

    Energy Technology Data Exchange (ETDEWEB)

    Denys, Sebastien; Echevarria, Guillaume E-mail: guillaume.echevarria@ensaia.inpl-nancy.fr; Florentin, Louis; Leclerc-Cessac, Elisabeth; Morel, Jean-Louis

    2003-07-01

    Models for safety assessment of radioactive waste repositories need accurate values of the soil-to-plant transfer of radionuclides. In oxidizing environments, {sup 99}Tc is expected to occur as pertechnetate ({sup 99}TcO{sub 4}{sup -}). Due to its high mobility, leaching of this element in the field might be important, potentially affecting the reliability of estimated transfer parameters of {sup 99}Tc as measured in closed experimental systems such as hydroponics or pot experiments. The aim of this experiment was to measure the leaching of {sup 99}Tc in undisturbed irrigated soil cores under cultivation as well as plant uptake and to study the possible competition between the two transfer pathways. Undisturbed soil cores (50x50 cm) were sampled from a Rendzic Leptosol (R), a colluvial Fluvic Cambisol (F) and a Dystric Cambisol (D) using PVC tubes (three cores sampled per soil type). Each core was equipped with a leachate collector at the bottom, allowing the monitoring of {sup 99}Tc leaching through the cores. Cores were placed in a greenhouse and maize (Zea mays L., cv. DEA, Pioneer[reg]) was sown. After 135 d, maize was harvested and radioactivity determined in both plant and water samples. Results showed that during the growing period, leaching of {sup 99}Tc was limited, due to the high evapotranspiration rate of maize. After harvest, leaching of {sup 99}Tc went on because of the absence of evapotranspiration. Effective uptake (EU) of {sup 99}Tc in leaves and grains was calculated. EU reached 70% of the input in the leaves and was not significantly different among soils. These results confirmed those obtained from pot experiments, even though leaching was allowed to occur in close-to-reality hydraulical conditions. As a consequence, it was concluded that pot experiments are an adequate surrogate for more complex 'close-to-reality' experimental systems for measuring transfer factors.

  3. Electron Spin Pairing and the Phase Diagram of High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; HAN Ru-Shan

    2001-01-01

    The origin of the instability of the normal state of electrons in the superconducting copper oxides is shown by the K-J model, in which the superexchange (K) between local moments and the Kondo exchange ( J) between electron and local moment are considered. The suppression of superexchange via impurity doping may induce effective spin coupling between electrons and triplet pairing (S = 1, Sz = 0). The spin pairing theory explains the phase diagram of high-To superconductors, especially the superconducting transition temperature Tc, the pseudogap temperature T* and the magnetic crossover temperature Tn as a function of the doped hole concentration. The universal expression for the empirical law of the superconducting transition temperature is derived from the theory.

  4. Scintigraphic imaging with {sup 99m}Tc- exorphin C in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Ertay, T. [Department of Nuclear Medicine, Medical School, Dokuz Eyluel University, Inciralti (Turkey)]. E-mail: turkan.ertay@deu.edu.tr; Uenak, P. [Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, Bornova (Turkey); Tasci, C. [Department of Nuclear Medicine, Medical School, Dokuz Eyluel University, Inciralti (Turkey); Zihnioglu, F. [Department of Biochemistry, Faculty of Sciences, Ege University, Bornova, Izmir (Turkey); Durak, H. [Department of Nuclear Medicine, Medical School, Dokuz Eyluel University, Inciralti (Turkey)

    2005-06-01

    Exorphin C is a peptide with five amino acids [(Tyr-Pro-Ile-Ser-Leu) Trifluoroacetate salt] (Sigma) that has an affinity to opioid receptor-expressing tissues and tumors. Exorphin-C was labeled with {sup 99m}Tc using glucoheptonate (GH) as bifunctional chelating agent. Then, we investigated its radiopharmaceutical potential as opioid receptor-expressing tissue on rabbits. Quality controls were performed by ITLC, paper electrophoresis and HPLC. Labeling efficiency was higher than 98%. The compound was stable for at least 5 h at room temperature. Scintigraphic imaging with {sup 99m}Tc-GH-exorphin C ({sup 99m}Tc-GE) was performed on male Albino rabbits. Static images were obtained from anterior projection using a Camstar XR/T gamma camera at several time intervals. Although a significant amount of activity was seen in the brain, less activity was seen on receptor saturation studies at 30 min. Slight hepatobiliary excretion was seen, though the main excretion route was renal. After saturating, the receptor hepatobiliary excretion was not seen; the only excretion route was renal.

  5. Continuous tailward flow in the near-Earth magnetotail observed by TC-1 satellite

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; LIU ZhenXing; MA ZhiWei; PU ZuYin; WANG JiYe; SHEN Chao

    2007-01-01

    On July 11, 2004, a substorm process in the period of continuous tailward flow was observed by the joint exploration of the TC-1, IMAGE and ACE satellites. The substorm observed by the TC-1 in the near-Earth has three stages: the growth phase (from 11:43 to 12:19), the pre-expansion process (from 12:19 to 12:28) and the dipolarization process. The auroral brightening was at 12:26 recorded by the FUV instrument on IMAGE, and the dipolarization occurred two minutes later. During the 45 min period of the tailward flow, the magnetotail experienced the growth phase and the pre-expansion process. When the dipolarization process began, the TC-1 entered the plasma sheet and observed a high speed earthward flow. The field-aligned tailward flow is characterized by the low temperature and high density, which is consistent with the properties of the flow from the ionosphere detected in the near-Earth magnetotail by other satellites. The tailward flow is closely related with the southward interplanetary magnetic field (IMF), and may have an important effect on the substorm.

  6. Introduction to IEC TC115 3rd Plenary Meeting and the Recent Work of SAC/TC324%IEC TC115第3次全会和SAC/TC324工作近况

    Institute of Scientific and Technical Information of China (English)

    舒印彪; 刘泽洪; 范建斌; 于永清

    2011-01-01

    为了及时掌握高压直流输电技术的国际标准化动态并明确未来几年的工作方向,详细描述了2011年11月在德国柏林召开的国际电工委员会(IEC)第115技术委员会(TC115)第3次全会的情况,概述了IEC TC115各工作组和项目组近期的工作动态。最后,介绍了全国高压直流输电工程标准化技术委员会(SAC/TC324)近期的工作进展情况。%In order to master the latest trend of the international standardization in HVDC transmission field and make clear the direction of the work in the coming years,we detailed the 3rd plenary meeting of International Electrotechnical Committee(IEC) 115th Technical Committee(TC115) held in Berlin,Germany in Nov.,2011,and overviewed IEC TC115 WG1,WG2,WG3 and PT1 meetings.Moreover,the recent work of the Standardization Technical Committee for HVDC power transmission project(SAC/TC324) in China was described.

  7. Application of Ionic Liquids for Tc Recovery from Aqueous Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Dominique C.; Shkrob, Ilya A.; Vandegrift, George F. [Argonne National Laboratory, Chemical Sciences and Engineering Division, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Wishart, James F. [Brookhaven National Laboratory (United States); Dietz, Mark L. [University of Wisconsin at Milwaukee (United States)

    2009-06-15

    Removal of technetium (Tc) from spent fuel waste is important because of its high mobility and long half-life. Current method of removal of Tc(VII) from the Tc product stream of the UREX process is a lengthy and complicated process which involves a multi-step chemical reduction of Tc from aqueous solution. Ionic liquids (ILs) have a potential to simplify separation and reduction of Tc from spent fuel streams. Studies of the extraction of actinides and fission products into ILs have demonstrated that these solvents can yield metal ion extraction efficiencies far exceeding those obtained in conventional liquid-liquid systems. Furthermore, ionic liquids are finding an increasing number of applications in electrodeposition of metals as their electrochemical window can reach more than 4 V and thus gives access to a number of elements that can not be electrodeposited from aqueous solutions. These finding suggest that ionic liquids can be used for separation of pertechnetate and subsequent electrodeposition on an electrode, to produce a metallic waste form. In this presentation we will present our progress on examining ionic liquids based extraction media for the separation of Tc(VII) from aqueous ammonia solutions. (authors)

  8. Scintigraphic findings on {sup 99m}Tc-MDP, {sup 99m}Tc-sestamibi and {sup 99m}Tc-HMPAO images in Gaucher`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Mariani, G. [Nuclear Medicine Service, DIMI, University of Genoa (Italy); Molea, N. [Regional Center of Nuclear Medicine, University of Pisa (Italy); La Civita, L. [Rheumatology Unit, University of Pisa (Italy); Porciello, G. [Rheumatology Unit, University of Pisa (Italy); Lazzeri, E. [Regional Center of Nuclear Medicine, University of Pisa (Italy); Ferri, C. [Rheumatology Unit, University of Pisa (Italy)

    1996-04-01

    We report here on the use of the lipophilic cationic complex technetium-99m sestamibi ({sup 99m}Tc-MIBI), employed as an indicator of increased cellular density and metabolic activity, to evaluate Gaucher cell infiltrates in the bone marrow; {sup 99m}Tc-hexametazime ({sup 99m}Tc-HMPAO) was also employed, as a pure indicator of lipidic infiltration in the bone marrow. A 67-year-old patient with known type 1 Gaucher`s disease presented with a painful left hip and knee and difficulty in gait subsequent to traumatic fracture of the left femoral neck that had required implant of a fixation screw-plaque. Bone scan with {sup 99m}Tc-methylene diphosphonate revealed reduced uptake at the distal metaphyseal-epiphyseal femoral region. In addition, whole-body maps and spot-view acquisitions of the thighs and legs were recorded at both 30 min and 2.5 h after the injection of {sup 99m}Tc-MIBI: the scintigraphic pattern clearly showed increased uptake at several sites involved by Gaucher deposits in the bone marrow (both knees, with variable intensity in different areas), matching the bone changes detected by conventional x-ray. The target to non-target ratios slowly decreased with time, from an average value of 2.25 in the early scan to an average value of 2 in the delayed scan. The lipid-soluble agent {sup 99m}Tc-HMPAO exhibited a superimposable scintigraphic pattern of accumulation at the involved sites, though with lower target to non-target ratios (1.27-1.48). The results obtained in this patient suggest a potential role of {sup 99m}Tc-MIBI in the scintigraphic evaluation of Gaucher`s lipid deposits in the bone marrow. If the results are confirmed in other patients, this radiopharmaceutical would offer clear advantages over {sup 133}Xe because of its wider availability and greater practicality (i.v. administration of {sup 99m}Tc-MIBI versus inhalation of {sup 133}Xe, and use of a single gamma camera instead of two as with {sup 133}Xe). (orig.). With 3 figs.

  9. Introduction to the EC's Marie Curie Initial Training Network project: The European training network in digital medical imaging for radiotherapy (ENTERVISION

    Directory of Open Access Journals (Sweden)

    Manjit eDosanjh

    2015-12-01

    Full Text Available Between 2011 and 2015, the ENTERVISION Marie Curie Initial Training Network has been training 15 young researchers coming from a variety of backgrounds on topics ranging from in-beam Positron Emission Tomography or Single Particle Tomography techniques, to adaptive treatment planning, optical imaging, Monte Carlo simulations, biological phantom design. This article covers the main research activities, as well as the training scheme implemented by the participating institutes, which included academia, research, and industry.

  10. Estimating the Curie point depth using aeromagnetic data with a fractal model in the Province of Québec, eastern Canada

    Science.gov (United States)

    Drolet, Jean-Philippe; Giroux, Bernard; Bouligand, Claire

    2017-04-01

    New technologies that allow geothermal energy production in colder conditions result in interest for geothermal exploration in low heat flux regions that were previously overlooked. The Province of Québec, eastern Canada, is such a case. It is a large and cold area with a low amount of heat flux measurements, and mapping the Curie point depth is appealing as an exploration tool due to the scarcity of the direct data. For that purpose, we have revisited a methodology to estimate the Curie point depth using a fractal source distribution model and aeromagnetic data. Our methodology relies on a statistical model of crustal magnetization having a constant magnetization direction and random magnetization amplitude. The shape of the radial average of the logarithm of the power spectrum of magnetic anomalies is predicted using this model. The model parameters (thickness and depth to the top of the magnetic layer, the fractal exponent β and the constant C') are obtained by calculating the best fit between the theoretical and observed radial power spectra using a non-linear least-square algorithm. Rather than using a constant value for the fractal exponent β over the whole study area, which would overcorrect the shape of the radially averaged power spectra in some zones, we propose a new calibration workflow based on heat flux measurements and lithology. This workflow includes the use of sequential Gaussian simulations (SGS) of heat flux data to enlarge the limited available dataset. The use of SGS also allows quantifying the uncertainty and the range of the predicted Curie point depths. This work contributes to mapping the Curie point depth at large scale and help identifying potential areas for further detailed exploration programs and potential geothermal energy production in the Province of Québec.

  11. Introduction to the EC's Marie Curie Initial Training Network Project: The European Training Network in Digital Medical Imaging for Radiotherapy (ENTERVISION).

    Science.gov (United States)

    Dosanjh, Manjit; Cirilli, Manuela; Navin, Sparsh

    2015-01-01

    Between 2011 and 2015, the ENTERVISION Marie Curie Initial Training Network has been training 15 young researchers from a variety of backgrounds on topics ranging from in-beam Positron Emission Tomography or Single Particle Tomography techniques, to adaptive treatment planning, optical imaging, Monte Carlo simulations and biological phantom design. This article covers the main research activities, as well as the training scheme implemented by the participating institutes, which included academia, research, and industry.

  12. Introduction to the EC’s Marie Curie Initial Training Network Project: The European Training Network in Digital Medical Imaging for Radiotherapy (ENTERVISION)

    Science.gov (United States)

    Dosanjh, Manjit; Cirilli, Manuela; Navin, Sparsh

    2015-01-01

    Between 2011 and 2015, the ENTERVISION Marie Curie Initial Training Network has been training 15 young researchers from a variety of backgrounds on topics ranging from in-beam Positron Emission Tomography or Single Particle Tomography techniques, to adaptive treatment planning, optical imaging, Monte Carlo simulations and biological phantom design. This article covers the main research activities, as well as the training scheme implemented by the participating institutes, which included academia, research, and industry. PMID:26697403

  13. On the 'artificial' nature of Tc and the 'carrier-free' nature of {sup 99m}Tc from {sup 99}Mo/{sup 99m}Tc generators

    Energy Technology Data Exchange (ETDEWEB)

    Alfassi, Zeev B. [Department of Nuclear Engineering, Ben Gurion University, Beer Sheva, 84105 (Israel)]. E-mail: alfassi@bgumail.bgu.ac.il; Groppi, Flavia [Universita degli Studi and INFN-Milano, LASA, Radiochemistry Laboratory Via F.lli Cervi 201, 20090 Segrate, Milan (Italy); Bonardi, Mauro L. [Interfaculty Reactor Institute Delft, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Goeij, Jeroen J.M. de [Interfaculty Reactor Institute Delft, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

    2005-07-01

    Two widespread misconceptions regarding Tc are dealt with. First, it is shown that although primordial Tc has decayed completely, Tc is still present in nature due to natural processes, in addition to substantial man-made quantities. Thus, Tc cannot be considered as a purely artificial element. Second, it is shown that {sup 99m}Tc from {sup 99}Mo/{sup 99m}Tc generators is certainly not carrier-free (CF) and that, 'no-carrier-added' (NCA) is a more appropriate designation. As a quantitative measure of the amount of long-lived {sup 99g}Tc carrier present in {sup 99m}Tc preparations from generators, the Isotope Dilution Factor (IDF) is used and calculated for some practical situations.

  14. Report on the Workshop and Regular Meeting of the Imode-CKD and Bcmolmed Marie Curie Training and Research Programs.

    Science.gov (United States)

    Krochmal, Magdalena; Cisek, Katryna; Markoska, Katerina; Spasovski, Goce; Vlahou, Antonia

    2015-01-01

    A Workshop and Regular Meeting of the Marie Curie Training and Research Programs iMODECKD (Identification of the Molecular Determinants of established Chronic Kidney Disease) and BCMolMed (Molecular Medicine for Bladder Cancer) was held from 20-22 March at the Macedonian Academy of Science and Arts (MASA). The meeting was hosted by the participating center University of Skopje (SKO) - Goce Spasovski and MASA - Momir Polenakovic (R. Macedonia). The representative from MASA proteomic research center - Katerina Davalieva (R. Macedonia) had presentation on proteomic research in prostate cancer (PCa). 40 researchers from 13 different countries participated at the meeting. The Workshop was devoted on "Chronic Kidney Disease: Clinical Management issues", and consisted of 15 oral presentations given by nephrologists and experts in the field of CKD. Raymond Vanholder (Belgium) - past president of ERA-EDTA had a keynote lecture on "CKD: Questions that need to be answered and are not (or at least not entirely)". The workshop continued in four sessions with lectures from Alberto Ortiz (Spain), Olivera Stojceva-Taneva (R. Macedonia), Dimitrios Goumenos (Greece), Joachim Beige (Germany), Marian Klinger (Poland), Goce Spasovski (R. Macedonia), Joachim Jankowski (Germany), Adalbert Schiller (Romania), Robert Johnson (USA), Franco Ferrario (Italy), Ivan Rychlik (Czech Republic), Fulvio Magni (Italy) and Giovambattista Capasso (Italy), all covering a training theme. Within the meeting there were two lectures on complimentary skills for ethics in science and career advancement from two principal investigators - Goce Spasovski (R. Macedonia) and Joost Schanstra (France). During the Regular Meeting, 13 PhD students i.e. Early Stage Researchers and one Experienced Researcher from both Programs presented their work and progress within iMODE-CKD and BCMolMed projects. This meeting was a great opportunity to exchange experience and ideas in the field of systems biology approaches and

  15. Separation of tc from Uranium and development of metallic Technetium waste forms

    Science.gov (United States)

    Mausolf, Edward John

    The isotope Technetium-99 (99Tc) is a major fission product of the nuclear industry. In the last decade, approximately 20 tons of 99Tc have been produced by the US nuclear industry. Due to its long half-life (t1/2 = 214,000 yr), beta radiotoxicity, and high mobility as pertechnetate [TcO4]-, Tc represents long-term concern to the biosphere. Various options have been considered to manage 99Tc. One of them is its separation from spent fuel, conversion to the metal and incorporation into a metallic waste form for long-term disposal. After dissolution of spent fuel in nitric acid and extraction of U and Tc in organic media, previously developed methods can be used to separate Tc from U, convert the separate Tc stream to the metal and reuse the uranium component of the fuel. A variety of metallic waste forms, ranging from pure Tc metal to ternary Tc alloys combined with stainless steel (SS) and Zr are proposed. The goal of this work was to examine three major questions: What is the optimal method to separate Tc from U? After separation, what is the most efficient method to convert the Tc stream to Tc metal? Finally, what is the corrosion behavior of Tc metal, Tc-SS alloys and Tc-Zr-SS alloys in 0.01M NaCl? The goal is to predict the long term behavior of Tc metallic waste in a hypothetical storage environment. In this work, three methods have been used to separate Tc from U: anionic exchange resin, liquid-liquid extraction and precipitation. Of the three methods studied, anionic exchange resins is the most selective. After separation of Tc from U, three different methods were studied to convert the Tc stream to the metal: thermal treatment under hydrogen atmosphere, electrochemical and chemical reduction of pertechnetate in aqueous media. The thermal treatment of the Tc stream under hydrogen atmosphere is the preferred method to produce Tc metal. After Tc metal is isolated, it will be incorporated into a metal host phase. Three different waste forms were produced for

  16. Poor Tc-99m dimercaptosuccinic acid uptake, re-evaluation with Tc-99m MAG3 scintigraphy in Lowe syndrome

    OpenAIRE

    Koca, Gokhan; Atilgan, Hasan Ikbal; Demirel, Koray; Diri, Akif; KORKMAZ, Meliha

    2011-01-01

    Tc-99m dimercaptosuccinic acid (DMSA) is filtered through the glomeruli and reabsorbed by the proximal tubules as low molecular weight proteins. In Lowe syndrome this mechanism is impaired and so poor DMSA uptake is seen. Poor DMSA uptake was shown in very few studies, but none mentioned normal Tc-99m MAG3 uptake. In this case, the patient had poor DMSA uptake, normal MAG3 uptake and a neurogenic bladder in anterior to the left kidney that attenuates left kidney.

  17. Production optimization of 99Mo/99mTc zirconium molybate gel generators at semi-automatic device: DISIGEG.

    Science.gov (United States)

    Monroy-Guzman, F; Rivero Gutiérrez, T; López Malpica, I Z; Hernández Cortes, S; Rojas Nava, P; Vazquez Maldonado, J C; Vazquez, A

    2012-01-01

    DISIGEG is a synthesis installation of zirconium (99)Mo-molybdate gels for (99)Mo/(99m)Tc generator production, which has been designed, built and installed at the ININ. The device consists of a synthesis reactor and five systems controlled via keyboard: (1) raw material access, (2) chemical air stirring, (3) gel dried by air and infrared heating, (4) moisture removal and (5) gel extraction. DISIGEG operation is described and dried condition effects of zirconium (99)Mo- molybdate gels on (99)Mo/(99m)Tc generator performance were evaluated as well as some physical-chemical properties of these gels. The results reveal that temperature, time and air flow applied during the drying process directly affects zirconium (99)Mo-molybdate gel generator performance. All gels prepared have a similar chemical structure probably constituted by three-dimensional network, based on zirconium pentagonal bipyramids and molybdenum octahedral. Basic structural variations cause a change in gel porosity and permeability, favouring or inhibiting (99m)TcO(4)(-) diffusion into the matrix. The (99m)TcO(4)(-) eluates produced by (99)Mo/(99m)Tc zirconium (99)Mo-molybdate gel generators prepared in DISIGEG, air dried at 80°C for 5h and using an air flow of 90mm, satisfied all the Pharmacopoeias regulations: (99m)Tc yield between 70-75%, (99)Mo breakthrough less than 3×10(-3)%, radiochemical purities about 97% sterile and pyrogen-free eluates with a pH of 6.

  18. The Curie laboratory. In the middle of a competence network. The study of radioactivity is an enterprise at multiple components; Le laboratoire Curie. Au coeur d`un reseau de competence. L`etude de la radioactivite est une entreprise a composantes multiples

    Energy Technology Data Exchange (ETDEWEB)

    Boudia, S. [Centre de recherche en histoire des sciences et des techniques a la Villette, 75 - Paris (France)

    1997-07-01

    After the first world war, the most important research laboratory is placed under the direction of a woman: Marie Curie. She leads a voluntarist policy to weave links with industry, the medical profession, and public authorities. In this network, circulate men, women, radium samples,calibration certificates, money, measuring instruments. (N.C.)

  19. Novel Tc-99m radiotracers for brain imaging

    Directory of Open Access Journals (Sweden)

    Alessandra Boschi

    2007-09-01

    Full Text Available A novel class of Tc-99m complexes able to cross the blood brain barrier has been investigated and described here. These compounds are formed by reacting the bis-substituted nitrido precusors [99mTc(N(PS2] (PS = phosphino-thiol ligand with triethylborane (BEt3 under strictly anhydrous conditions and using non-aqueous solvents. The molecular structure of these tracers was not fully established, but preliminary experimental evidence suggests that they result from the interaction of the Lewis base [99mTc(N(PS2] with the Lewis acid BEt3, which leads to the formation of the novel -B-Nº Tc- adduct. After purification and recovery in a physiological solution, the new borane-nitrido Tc-99m derivatives were injected in rats for evaluating their in vivo biological behavior. Results showed a significant accumulation in brain tissue, thus indicating that these complexes are capable of penetrating the intact blood brain barrier. Uptake in the central nervous system was confirmed by imaging the distribution of activity on the integrated living animal using a YAP(SSPECT small animal scanner.Uma nova classe de complexos de Tc-99m capazes de atravessar a barreira hemato-encefálica foi investigada e descrita neste trabalho. Estes compostos são formados reagindo os precursores bissubstituídos do nitrido [99mTc(N(PS2] (PS = phosphino-tiol ligante com trietillborano (BEt3 sob restritas condições anidras e usando solventes não aquosos. A estrutura molecular desses traçadores não foi totalmente estabelecida, mas evidências experimentais preliminares sugerem que eles resultam da interação da base de Lewis [99mTc(N(PS2] com o ácido de Lewis BEt3, levando a formação do novo aducto -B-Nº Tc-. Após purificação e recuperação em uma solução fisiológica, os novos derivados borano-nitrido-Tc-99m foram injetados em ratos para avaliação de seu comportamento biológico in vivo. Os resultados mostraram uma acumulação significativa no tecido cerebral

  20. {sup 99m}Tc-ECD and {sup 99m}Tc-HM-PAO SPECT in five patients with MELAS

    Energy Technology Data Exchange (ETDEWEB)

    Katagiri, Shinako; Nishimaki, Hiroshi; Kitano, Masashi; Horiike, Shigeharu; Kan, Shinichi; Ishii, Katsumi; Matsubayashi, Takashi; Sakai, Fumihiko [Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Medicine

    1998-03-01

    Cerebral perfusion was studied in five patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes syndrome (MELAS), using single photon emission computed tomography (SPECT) with {sup 99m}Tc-ethyl cysteinate dimer ({sup 99m}Tc-ECD) or {sup 99m}Tc-hexamethyl propyleneamine oxime ({sup 99m}Tc-HM-PAO). In four cases, regional cerebral blood flow (rCBF) was evaluated by the method reported by Mastuda et al. Immediately after the stroke-like episodes, accumulation of the tracer was relatively increased in the temporooccipital lobe, and also increased rCBF was shown in the same area. However, the region showed decreased radioactivity at the chronic stage, and rCBF decreased also. These findings are consistent with positron emission tomography (PET) at the acute stage and autopsy. {sup 99m}Tc-ECD SPECT and {sup 99m}Tc-HM-PAO SPECT may be useful in the diagnosis and assessment of the progress of the MELAS. (author)

  1. Determining magnetic phase transitions temperatures in working magnetocaloric coolers bodies and gas cryorefrigerators regenerators

    Science.gov (United States)

    Karagusov, V. I.; Mayankov, I. V.

    2017-08-01

    Due to magnetic phase transitions rare-earth materials possess unique properties near the Curie and Neel temperatures, such as the magneto-caloric effect, the abnormally high heat capacity, the magnetic susceptibility and permeability extremes. Using rare earth materials in gas cryogenic refrigerators regenerators increases the efficiency, reduces the power consumption and allows reaching helium temperatures. The magneto-caloric effect has also extreme values near the Curie and Neel temperatures. The paper presents theoretical and experimental methods allowing to determine magnetic phase transitions temperatures in a wide range of low temperature materials with a various rare-earth components content and expected thermophysical properties of a certain rare-earth materials composition at the temperatures based on starting pure metals characteristics. The results analysis has shown that magnetic phase transitions temperatures are a linear function of the components concentration. Moreover, heat capacity values and MCE also depend linearly on the starting components concentration, which simplifies calculations significantly.

  2. Enhancement of Structure, Tc and Irreversibility Line in High Tc Superconductors by Heat Treatments

    Directory of Open Access Journals (Sweden)

    Abdeljabar Aboulkassim

    2015-08-01

    Full Text Available AC susceptibility (ac= ’+ i‖ and X ray diffraction (XRD are very useful for characterizing high Tc superconductors. We report here on the preparation, X-ray diffraction with Rietveld refinement, resistivity , AC magnetic susceptibility measurements and effect of heat treatments in (Y1-xNdxSrBaCu3O6+z. Each sample was subject to two types of heat treatment: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. For each x, the [AO] heat treatment increases the orthorhombicity ε = (b-a/(b+a (for 0≤x0.2, the distance d[Cu(1-(Sr/Ba] (for x0.25; increase in cationic and chain oxygen ordering; psh and in-phase purity for the [AO] samples may account for the observed data.

  3. Band-Structure Trend in Hole-Doped Cuprates and Correlation with {Tc}{sub MAX}

    Energy Technology Data Exchange (ETDEWEB)

    Pavarini, E.; Dasgupta, I.; Saha-Dasgupta, T.; Jepsen, O.; Andersen, O. K.

    2001-07-23

    By calculation and analysis of the bare conduction bands in a large number of hole-doped high-temperature superconductors, we have identified the range of the intralayer hopping as the essential, material-dependent parameter. It is controlled by the energy of the axial orbital, a hybrid between Cu4s , apical-oxygen 2p{sub z} , and farther orbitals. Materials with higher {Tc}{sub max} have larger hopping ranges and axial orbitals more localized in the CuO{sub 2} layers.

  4. Electric and magnetic characterization of NbSe 2 single crystals: Anisotropic superconducting fluctuations above TC

    Science.gov (United States)

    Soto, F.; Berger, H.; Cabo, L.; Carballeira, C.; Mosqueira, J.; Pavuna, D.; Toimil, P.; Vidal, F.

    2007-09-01

    Electric and magnetic characterization of NbSe 2 single crystals is first presented in detail. Then, some preliminary measurements of the fluctuation-diamagnetism (FD) above the transition temperature TC are presented. The moderate uniaxial anisotropy of this compound allowed us to observe the fluctuation effects for magnetic fields H applied in the two main crystallographic orientations. The superconducting parameters resulting from the characterization suggest that it is possible to do a reliable analysis of the FD in terms of the Ginzburg-Landau (GL) theory.

  5. Extended abstracts of the 12th JAERI workshop on high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishida, Takekazu [Osaka Prefectual Univ., Sakai (JP)] (eds.)

    2001-03-01

    This workshop was held on December 7-8, 2000 at JAERI (Tokai). The research group at JAERI shares a responsibility for material modification of high-Tc superconductors by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by STA (Science and Technology Agency) of Japan. This report contains the extended abstracts of workshop presentations covering basic theories, various experimental results and material improvement studies of the superconductivity by high energy ion irradiation. The twelve presentations of the workshop were devoted to a mini symposium where the direct observations of vortices were discussed in view of the various sophisticated techniques. (author)

  6. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  7. Power Systems Development Facility Gasification Test Campaign TC25

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-12-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

  8. Power Systems Development Facility Gasification Test Campaign TC25

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-12-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

  9. Optimization of HighTc Josephson nanojunctions by Monte Carlo simulations

    Science.gov (United States)

    Sirena, M.; Bergeal, N.; Lesueur, J.; Faini, G.; Bernard, R.; Briatico, J.; Crete, D.

    2007-03-01

    The fabrication of YBCO JJ by ion damage is the best method that allows closed packed JJ series within the nanoscale and that could operate at high temperature. However, the strong variation of the JJ's critical current with temperature (T) and the increase of dispersion for high irradiation dose are still important issues for several applications. Reproducible HTc JJ have been produced combining electron beam lithography and ion beam irradiation, whose characteristics can be adjusted on a wide range of T. To further improve the homogeneity of planar JJ and optimize their behaviour, we have studied its lateral ion damage distribution (LDD) for different ions and incident energies using Monte Carlo simulations. The LDD was used to calculate the transition temperature (Tc') of the irradiated zone and its resistance as a function of T. Dispersion in the irradiation mask's size was introduced as the source of the JJ's in-homogeneity. The simulations results reproduce quite well the observed dispersion of the irradiated JJ. A linear behaviour of the JJ's Tc' dispersion with basically the LDD width was found, independent of the incident ions mass, its energy, the films thickness, etc. By choosing the appropriate parameters is possible to increase the JJ homogeneity, reducing the LDD width.

  10. Infrared spectra of the high- Tc TlBaCaCuO superconductors

    Science.gov (United States)

    Yanru, Ren; Hanpeng, Liu; Mingzhu, Lin; Qingyun, Tu; Lihua, Sang; Zhenjin, Lin; Xianren, Meng; Zhenxing, Liu

    1988-12-01

    The TlBaCaCuO superconductors with zero resistance at temperatures in the range of 100-123 K have been sintered by solid state reactions. Electron microscopy and X-ray diffraction studies reveal that they are multiphased, containing both Tl 2Ba 2CaCu 2O 8 and Tl 2Ba 2Ca 2Cu 3O 10 superconducting phases. Infrared spectra have been measured at room temperature for the multiphase samples. The spectra display structures at ∼590 cm -1 ( P1) and ∼530 cm -1 ( P2) which seem characteristic to Cu-O stretching modes. The difference Δ P between P1 and P1 has been found to be related to the superconducting transition temperature. Smaller Δ P corresponds to a higher Tc. The electron-like excitation of∼0.1 eV and the phonon-like structure at ∼850 cm -1 are also found to be important for high Tc.

  11. Imaging of brain tumors and other lesions utilizing /sup 99m/Tc phosphates and /sup 99m/Tc pertechnetate

    Energy Technology Data Exchange (ETDEWEB)

    Schauwecker, D.S.; Burt, R.W.; Richmond, B.D.

    1982-11-01

    The intensity of parenchymal brain lesions was compared using /sup 99m/Tc pertechnetate and /sup 99m/Tc phosphate. The following conclusions were made: 1. If the /sup 99m/Tc phosphate intensity is greater than the intensity of the /sup 99m/Tc pertechnetate scan, and the patient is evaluated within four weeks of ictus, the lesion is a CVA (P less than .001). 2. If the /sup 99m/Tc phosphate intensity is less than or equal to the intensity of the /sup 99m/Tc pertechnetate scan, and the patient is evaluated within four weeks of ictus, the parenchymal lesion is not a CVA (P less than .001). 3. If the evaluation takes place longer than six weeks after ictus, then no evaluation about the nature of the lesion can be made based upon uptake of /sup 99m/Tc phosphate and /sup 99m/Tc pertechnetate.

  12. Novel (99m)Tc(III) Complexes [(99m)TcCl(CDO)(CDOH)2B-R] (CDOH2 = Cyclohexanedione Dioxime) Useful as Radiotracers for Heart Imaging.

    Science.gov (United States)

    Liu, Min; Fang, Wei; Liu, Shuang

    2016-11-16

    In this study, we evaluated seven new (99m)Tc(III) complexes [(99m)TcCl(CDO)(CDOH)2B-R] ((99m)Tc-2Fboroxime: R = 2-formylfuran-3-yl (2F); (99m)Tc-3Fboroxime: R = furan-3-yl (3F); (99m)Tc-5Fboroxime: R = 5-formyfuran-2-yl (5F); (99m)Tc-HPboroxime: R = 6-hydroxylpyridin-2-yl (HP); (99m)Tc-MPYboroxime: R = 5-methoxypyridin-3-yl (MPY); (99m)Tc-PMboroxime: R = 1,5-pyrimidin-3-yl (PM); and (99m)Tc-4PYboroxime: R = pyridin-4-yl (4PY)) for their potential as heart imaging agents. All new (99m)Tc(III) radiotracers except (99m)Tc-2Fboroxime were prepared with high radiochemical purity (RCP > 95%). The low RCP (∼75%) for (99m)Tc-2Fboroxime is most likely caused by steric hindrance from the 3-formyl group. Biodistribution and imaging studies were performed in SD rats. Planar image quantification was performed to compare their myocardial retention times. We found that the myocardial washout curves of new (99m)Tc(III) radiotracers were best fitted the biexponential decay function. The AUC (area under the curve) values followed the general trend: (99m)Tc-5Fboroxime (129 ± 6) > (99m)Tc-3Fboroxime (114 ± 11) > (99m)Tc-Teboroxime (104 ± 16) > (99m)Tc-MPYboroxime (92 ± 18) > (99m)Tc-4PYboroxime (77 ± 10) > (99m)Tc-PMboroxime (68 ± 14) ≈ (99m)Tc-HPboroxime (62 ± 14). The 2 min heart uptake values from biodistribution studies follow the ranking order of (99m)Tc-5Fboroxime (3.75 ± 0.15%ID/g) ≈ (99m)Tc-MPYboroxime (3.73 ± 0.24%ID/g) > (99m)Tc-PMboroxime (3.47 ± 0.15%ID/g) ≈ (99m)Tc-3Fboroxime ≈ (3.25 ± 0.77%ID/g). The 5 min heart uptake of (99m)Tc-5Fboroxime (3.91 ± 0.09%ID/g) was almost identical to its 2 min heart uptake (3.75 ± 0.15%ID/g), and its 15 min heart uptake value (2.83 ± 0.08%ID/g) compared well to the 2 min heart uptake of (99m)Tc-Teboroxime (3.00 ± 0.37%ID/g). It took ∼5 min for (99m)Tc-5Fboroxime to approach the 1 min heart uptake value of (99m)Tc-Teboroxime (∼3.5% ID/g) and ∼9.5 min to reach the 2 min heart uptake value of (99m)Tc

  13. Doping dependence of the pressure response of Tc in the SmO(1-x)F(x)FeAs superconductors.

    Science.gov (United States)

    Takabayashi, Yasuhiro; McDonald, Martin T; Papanikolaou, Dionisis; Margadonna, Serena; Wu, G; Liu, R H; Chen, X H; Prassides, Kosmas

    2008-07-23

    The superconducting transition temperature of the high-Tc SmO1-xFxFeAs superconductors increases monotonically as the F-doping level x increases to 0.20. High-pressure magnetization experiments reveal a strong sensitivity of Tc to interatomic distances in the underdoped regime (x Tc, d(ln Tc)/dP being strongly positive. However, as the doping level increases further to x = 0.15, we find that this sensitivity is strongly suppressed and at the same time, d(ln Tc)/dP sharply switches over to assume negative values with Tc decreasing with increasing applied pressure. The abrupt change in the pressure response of the superconducting properties of the SmO1-xFxFeAs phases coincides with the putative existence of a quantum critical point (QCP) near x approximately 0.14, as proposed by resistivity and Hall effect measurements.

  14. Higher critical current density achieved in Bi-2223 High-Tc superconductors

    Directory of Open Access Journals (Sweden)

    M.S. Shalaby

    2016-07-01

    Full Text Available Bi2Sr2Ca2Cu3Ox (Bi-2223 were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature Tc and critical current density Jc values were measured using superconducting quantum interference device magnetometer (SQUID and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T at 110 K and Jc around 1.2 × 107 A/m2 at 5 K are confirmed for the Bi-2223 compound.

  15. Development of Tc-99m Imaging Agents for Abeta Plaques

    Energy Technology Data Exchange (ETDEWEB)

    Zhi-Ping, Zhuang; Mei-Ping Kung; Catherihne Hou; Hank F. Kung

    2008-09-26

    Development of SPECT imaging agents based on Tc-99m targeting Aβ plaques is useful for diagnosis of Alzheimer’s disease (AD). A stilbene derivative, [11C]SB-13, showing promise in detecting senile plaques present in AD patients has been reported previously1,2. Based on the 4’-amino-stilbene core structure we have added substituted groups through which a chelating group, N2S2, was conjugated. We report herein a series of Tc-99m labeled stilbene derivative conjugated with a TcO[N2S2] core. The syntheses of stilbenes containing a N2S2 chelating ligand are achieved by a scheme shown. Lipophilic 99mTc stilbene complexes were successfully prepared and purified through HPLC. Preliminary results of in vitro labeling of brain sections from transgenic mice showed very promising plaque labeling. These 99mTc stilbene derivatives are warranted for further evaluations as potential imaging agents targeting amyloid plaques.

  16. Long-Range Order and Critical Scattering of Neutrons below the Transition Temperature in β-Brass

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Dietrich, O.W.

    1967-01-01

    The temperature dependence of long-range order langPrang has been determined from the temperature variation of a superlattice Bragg reflection. The results fitted a power law langPrang prop (Tc-T)beta with Tc the critical temperature and beta = 0.305plusmn0.005, in agreement with the theoretical ...

  17. Emergent high-Tc ferroelectric ordering of strongly correlated and frustrated protons in a heteroepitaxial ice film

    Science.gov (United States)

    Sugimoto, Toshiki; Aiga, Norihiro; Otsuki, Yuji; Watanabe, Kazuya; Matsumoto, Yoshiyasu

    2016-11-01

    Materials containing strong correlation and frustration have the potential to respond to external perturbations in an unusual way. In the case of common water ice, protons in the hydrogen-bond network are strongly correlated and highly frustrated under Pauling's ice rules. At low temperature, the strongly correlated protons lose ergodicity, and little is understood about the cooperative thermodynamic and electric response to external stimuli. Here, using a model platinum substrate, we demonstrate emergent high-Tc ferroelectric proton ordering in a heteroepitaxial ice film. Such proton ordering is thermodynamically stable and has an extremely high critical temperature of ~175 K. We found that anisotropy and protolysis driven by the electrostatistics at the heterointerface are key factors in stimulating this novel exotic ordering in the many-body correlated proton system. The significant increase in Tc due to the heterointerface suggests the ubiquity of ferroelectric ice in nature--specifically, in space and the polar stratosphere.

  18. Canopy temperature for simulation of heat stress in irrigated wheat in a semi-arid environment: A multi-model comparison

    DEFF Research Database (Denmark)

    Webber, Heidi; Martre, Pierre; Asseng, Senthold

    2017-01-01

    evidence that crop canopy temperature (Tc) better explains grain yield losses. Tc can deviate significantly from Tair based on climatic factors and the crop water status. The broad objective of this study was to evaluate whether simulation of Tc improves the ability of crop models to simulate heat stress...

  19. Novel 99mTc labeled

    Institute of Scientific and Technical Information of China (English)

    FAN; Caiyun

    2006-01-01

    ,Nucl.Med.Biol.,2003,30:273-284.[33]John,C.S.,Lim,B.B.,Geyer,B.C.Et al.,99mTc-labeled σ-receptor-binding complex:Synthesis,characterization,and specific binding to human ductal breast carcinoma (T47D) cells,Bioconj.Chem.,1997,8:304-309.[34]Choi,S-R.,Yang,B.,P(o)ssl,K.Et al.,Development of a Tc-99m labeled sigma-2 receptor-specific ligand as a potential breast tumor imaging agent,Nucl.Med.Biol.,2001,28:657-666.[35]Zhang,Y.,Williams,W.,Torrence-Campbell,C.et al.,Characterization of novel N,N′-disubstituted piperazines as sigma receptor ligands,J.Med.Chem.,1998,41:4950-4957.[36]Maeda,D.N.,Williams,W.,Kim,W.E.et al.,N-arylalkylpi-peridines as high-affinuty sigma-1 and sigma-2 receptor ligands:Phenylpropylamine as potential leads for selective sigma-2 agents,Bioorg.Med.Chem.Lett.,2002,12:497-500.[37]Moore,T.S.,Boyle,M.,Thorn,V.M.et al.,N-substituted derivatives of piperazine and ethylenediamine,Part Ⅰ.The preparation of N-monosubstituted derivatives,J.Chem.Soc.,1929:39.[38]Stewart,H.W.,Turner,R.J.,Denton,J.J.et al.,Experimental chemotherapy of filariasis,Ⅳ.The preparation of derivatives of piperazine,J.Org.Chem.,1948,13:134-143.[39]O'Neil,J.P.,Wilson,S.R.,Katzenellenbogen,J.A.,Preparation and structural characterization of monoamine-monoamide bis(thio) oxo complexes of technetium(V) and rhenium(V),Inorg.Chem.,1994,33:319-323.[40]Bowen,W.D.,Sigma receptors:Recent advances and new clinical potentials,Pharm.Acta Helv.,2000,74:211-218.[41]Deuther-Conrad,W.,Patt,J.T.,Feuerbach,D.et al.,Norchloro-fluoro-homoepibatidine:Specificity to neuronal nicotinic acetylcholine receptor subtypes in vitro,IL Farmaco,2004,59:785-792.[42]Vilner,B.J.,Bowen,W.D.,Modulation of cellular calcium by sigma-2 receptors:Release form intracellular stores in human SK-N-SH neuroblastoma cells,J.Pharmacol.Exp.Ther.,2000,292:900-911.[43]Cheng,Y.,Prusoff,W.H.,Relationship between the inhibition constant (Ki) and the concentration of inhibitor which cause 50% inhibition (IC50) of an enzymatic reaction

  20. Finite temperature quantum correlations in su(2)(c) quark states and quantum spin models

    NARCIS (Netherlands)

    Hamieh, S; Tawfik, A

    2005-01-01

    The entanglement at finite temperatures is analyzed by using thermal models for colored quarks making tip the hadron physical states. We have found that these quantum correlations entirely vanish at T-c >= m(q)/ln(1.5). For temperatures larger than T-c the correlations are classical. We have also wo