La0.8Sr0.2Co0.8Ni0.2O3-δ impregnated oxygen electrode for H2O/CO2 co-electrolysis in solid oxide electrolysis cells

Science.gov (United States)

Zheng, Haoyu; Tian, Yunfeng; Zhang, Lingling; Chi, Bo; Pu, Jian; Jian, Li

2018-04-01

High-temperature H2O/CO2 co-electrolysis through reversible solid oxide electrolysis cell (SOEC) provides potentially a feasible and eco-friendly way to convert electrical energy into chemicals stored in syngas. In this work, La0.8Sr0.2Co0.8Ni0.2O3-δ (LSCN) impregnated Gd0.1Ce0.9O1.95 (GDC)-(La0.8Sr0.2)0.95MnO3-δ (LSM) composite oxygen electrode is studied as high-performance electrode for H2O/CO2 co-electrolysis. The LSCN impregnated cell exhibits competitive performance with the peak power density of 1057 mW cm-2 at 800 °C in solid oxide fuel cell (SOFC) mode; in co-electrolysis mode, the current density can reach 1.60 A cm-2 at 1.5 V at 800 °C with H2O/CO2 ratio of 2/1. With LSCN nanoparticles dispersed on the surface of GDC-LSM to maximize the reaction active sites, the LSCN impregnated cell shows significant enhanced electrochemical performance at both SOEC and SOFC modes. The influence of feed gas composition (H2O-H2-CO2) and operating voltages on the performance of co-electrolysis are discussed in detail. The cell shows a very stable performance without obvious degradation for more than 100 h. Post-test characterization is analyzed in detail by multiple measurements.

Magnetic behaviour of nano-particles of Fe2.8Zn0.2O4

Indian Academy of Sciences (India)

Magnetic behaviour of nano-particles of Fe2.8Zn0.2O4. SUBHASH CHANDER, SEEMA LAKHANPAL, ANJALI KRISHNAMURTHY,. BIPIN K SRIVASTAVA and V K ASWAL∗. Department of Physics, University of Rajasthan, Jaipur 302 004, India. *Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 ...

Raman scattering from In0.2Ga0.8N/GaN superlattices

International Nuclear Information System (INIS)

Kisoda, Kenji; Hirakura, Kohji; Harima, Hiroshi

2006-01-01

We have performed Raman scattering experiments on high quality In 0.2 Ga 0.8 N/GaN superlattices(SLs). The A 1 LO phonon mode from the In 0.2 Ga 0.8 N layer was observed in the Mg doped SL. This was attributable to manifestation of a resonance enhancement via acceptor levels formed by magnesium doping. The peak frequency of the A 1 LO mode shifted to high frequency side with the excitation energy. The frequency shift suggested that the composition of indium was fluctuated along the growth direction in the InGaN layer. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Microwave dielectric properties of (Ca0.8Sr0.2)(SnxTi1−x)O3 ceramics

International Nuclear Information System (INIS)

Hsu, Cheng-Hsing; Chang, Chia-Hao

2013-01-01

Highlights: ► New microwave dielectric properties of (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics were investigated. ► A single-phase solid solution containing orthorhombic Pbnm with different Sn contents was formed. ► A significant improvement of Q × f value and τ f were achieved by (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 system. ► Second phases were formed and affected the dielectric properties of (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 system. ► Low cost and suitable τ f value of (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 demonstrate a good potential for use in microwave device. -- Abstract: In this paper, we study the behavior of the B-site behavior with the incorporation of Sn 4+ ion in (Ca 0.8 Sr 0.2 )TiO 3 ceramics. An excess of Sn 4+ resulted in the formation of a secondary phase of CaSnO 3 and SrSnO 3 affecting the microwave dielectric properties of the (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics. The dielectric properties of the (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics were improved because of the solid solution of Sn 4+ substitution in the B-site. The temperature coefficient of resonant frequency (τ f ) of the (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics also improved with increasing Sn content

Modulation-doped β-(Al0.2Ga0.8)2O3/Ga2O3 field-effect transistor

Science.gov (United States)

Krishnamoorthy, Sriram; Xia, Zhanbo; Joishi, Chandan; Zhang, Yuewei; McGlone, Joe; Johnson, Jared; Brenner, Mark; Arehart, Aaron R.; Hwang, Jinwoo; Lodha, Saurabh; Rajan, Siddharth

2017-07-01

Modulation-doped heterostructures are a key enabler for realizing high mobility and better scaling properties for high performance transistors. We report the realization of a modulation-doped two-dimensional electron gas (2DEG) at the β-(Al0.2Ga0.8)2O3/Ga2O3 heterojunction by silicon delta doping. The formation of a 2DEG was confirmed using capacitance voltage measurements. A modulation-doped 2DEG channel was used to realize a modulation-doped field-effect transistor. The demonstration of modulation doping in the β-(Al0.2Ga0.8)2O3/Ga2O3 material system could enable heterojunction devices for high performance electronics.

Comparação entre troponina I cardíaca e CK-MB massa em síndrome coronariana aguda sem supra de ST Comparación entre troponina i cardíaca y ck-mb masa en síndrome coronario agudo sin supradesnivel de ST Comparison between cardiac troponin I and CK-MB mass in acute coronary syndrome without st elevation

Directory of Open Access Journals (Sweden)

Elizabete Silva dos Santos

2011-03-01

Full Text Available FUNDAMENTO: Há incertezas do valor prognóstico comparativo entre troponina I cardíaca (cTnI e CK-MB em síndrome coronariana aguda (SCA. OBJETIVO: Comparar o valor prognóstico entre a cTnI e a CK-MB massa em pacientes com SCA sem supradesnível do segmento ST. MÉTODOS: Foram analisados 1.027 pacientes, de modo prospectivo, em um centro terciário de cardiologia. Combinações dos biomarcadores foram examinadas: cTnI normal, CK-MB massa normal (65,5%; cTnI normal, CK-MB massa elevada (3,9%; cTnI elevada, CK-MB massa normal (8,8%; cTnI elevada, CK-MB massa elevada (20,7%. Análise multivariada de variáveis clínicas, eletrocardiográficas e laboratoriais determinou o valor prognóstico independente dos biomarcadores para o evento de morte ou (reinfarto em 30 dias. RESULTADOS: Pacientes com pelo menos um biomarcador elevado foram mais idosos (p = 0,02 e do sexo masculino (p FUNDAMENTO: Hay dudas sobre el valor pronóstico comparativo entre troponina I cardíaca (cTnI y CK-MB en síndrome coronario agudo (SCA. OBJETIVO: Comparar el valor pronóstico entre la cTnI y la CK-MB masa en pacientes con SCA sin supradesnivel del segmento ST. MÉTODOS: Fueron analizados 1.027 pacientes, de modo prospectivo, en un centro terciario de cardiología. Combinaciones de los biomarcadores fueron examinadas: cTnI normal, CK-MB masa normal (65,5%; cTnI normal, CK-MB masa elevada (3,9%; cTnI elevada, CK-MB masa normal (8,8%; cTnI elevada, CK-MB masa elevada (20,7%. Análisis multivariado de variables clínicas, electrocardiográficas y de laboratorio determinó el valor pronóstico independiente de los biomarcadores para el evento de muerte o (reinfarto en 30 días. RESULTADOS: Pacientes con por lo menos un biomarcador elevado eron más añosos (p = 0,02 y del sexo masculino (p BACKGROUND: There is uncertainty as to the comparative prognostic value between cardiac troponin I (cTnI and CK-MB in acute coronary syndrome (ACS. OBJECTIVE: To compare the prognostic

Thermophysical Properties and Structural Transition of Hg(0.8)Cd(0.2)Te Melt

Science.gov (United States)

Li, C.; Scripa, R. N.; Ban, H.; Lin, B.; Su, C.; Lehoczky, S. L.

2004-01-01

Thermophysical properties, namely, density, viscosity, and electrical conductivity of Hg(sub o.8)Cd(sub 0.2)Te melt were measured as a function of temperature. A pycnometric method was used to measure the melt density in the temperature range of 1072 to 1122 K. The viscosity and electrical conductivity were simultaneously determined using a transient torque method from 1068 to 1132 K. The density result from this study is within 0.3% of the published data. However, the current viscosity result is approximately 30% lower than the existing data. The electrical conductivity of Hg(sub o.8)Cd(sub 0.2)Te melt as a function of temperature, which is not available in the literature, is also determined. The analysis of the temperature dependent electrical conductivity and the relationship between the kinematic viscosity and density indicated that the structure of the melt appeared to be homogeneous when the temperature was above 1090 K. A structural transition occurred in the Hg(sub 0.8)Cd(0.2)Te melt as the temperature was decreased from 1090 K to the liquidus temperature.

A 3.1-4.8 GHz CMOS receiver for MB-OFDM UWB

International Nuclear Information System (INIS)

Yang Guang; Yao Wang; Yin Jiangwei; Zheng Renliang; Li Wei; Li Ning; Ren Junyan

2009-01-01

An integrated fully differential ultra-wideband CMOS receiver for 3.1-4.8 GHz MB-OFDM systems is presented. A gain controllable low noise amplifier and a merged quadrature mixer are integrated as the RF front-end. Five order Gm-C type low pass filters and VGAs are also integrated for both I and Q IF paths in the receiver. The ESD protected chip is fabricated in a Jazz 0.18 μm RF CMOS process and achieves a maximum total voltage gain of 65 dB, an AGC range of 45 dB with about 6 dB/step, an averaged total noise figure of 6.4 to 8.8 dB over 3 bands and an in-band IIP3 of -5.1 dBm. The receiver occupies 2.3 mm 2 and consumes 110 mA from a 1.8 V supply including test buffers and a digital module.

A 3.1-4.8 GHz CMOS receiver for MB-OFDM UWB

Energy Technology Data Exchange (ETDEWEB)

Yang Guang; Yao Wang; Yin Jiangwei; Zheng Renliang; Li Wei; Li Ning; Ren Junyan, E-mail: w-li@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

2009-01-15

An integrated fully differential ultra-wideband CMOS receiver for 3.1-4.8 GHz MB-OFDM systems is presented. A gain controllable low noise amplifier and a merged quadrature mixer are integrated as the RF front-end. Five order Gm-C type low pass filters and VGAs are also integrated for both I and Q IF paths in the receiver. The ESD protected chip is fabricated in a Jazz 0.18 mum RF CMOS process and achieves a maximum total voltage gain of 65 dB, an AGC range of 45 dB with about 6 dB/step, an averaged total noise figure of 6.4 to 8.8 dB over 3 bands and an in-band IIP3 of -5.1 dBm. The receiver occupies 2.3 mm{sup 2} and consumes 110 mA from a 1.8 V supply including test buffers and a digital module.

Dielectric behavior of samarium-doped BaZr0.2Ti0.8O3 ceramics

International Nuclear Information System (INIS)

Li, Yuanliang; Wang, Ranran; Ma, Xuegang; Li, Zhongqiu; Sang, Rongli; Qu, Yuanfang

2014-01-01

Graphical abstract: - Highlights: • We investigate dielectric properties and phase transition of Sm 3+ -doped BaZr 0.2 Ti 0.8 O 3 ceramics. • The additive amount of Sm 2 O 3 can greatly affect the dielectric properties. • The materials undergo a diffuse type ferroelectric phase transition. • There is an alternation of substitution preference of Sm 3+ ion for the host cations in perovskite lattice. - Abstract: The dielectric properties and phase transition of Sm 3+ -doped BaZr 0.2 Ti 0.8 O 3 (BZT20) ceramics were investigated. Room temperature X-ray diffraction study suggested that the compositions had single-phase cubic symmetry. Microstructure studies showed that the grain size decreased and that the Sm 2 O 3 amount markedly affected the dielectric properties of BZT20. A dielectric constant of 5700 at 0.2 mol% Sm 2 O 3 and a dissipation factor of only 0.0011 at 2 mol% Sm 2 O 3 were observed, indicating that BZT20 had significant potential applications. Moreover, the dielectric constant, dissipation factor, phase-transition temperature, and maximum dielectric constant increased with increased Sm 2 O 3 amount at ≤0.2 mol% Sm 2 O 3 but decreased with increased Sm 2 O 3 amount at >0.2 mol% Sm 2 O 3

Crystal structure and magnetic properties of PrCo6.8-xCuxHf0.2 compounds

International Nuclear Information System (INIS)

Luo, J; Liang, J K; Guo, Y Q; Liu, Q L; Liu, F S; Yang, L T; Zhang, Y; Rao, G H

2004-01-01

The effects of Cu substitution on the crystal structure and magnetic properties of PrCo 6.8-x Cu x Hf 0.2 (x = 0-1.0) compounds were investigated by means of x-ray powder diffraction and magnetic measurements. The as-cast PrCo 6.8-x Cu x Hf 0.2 compounds crystallize in the TbCu 7 -type structure with the space group P6/mmm. The Curie temperature and magnetic anisotropy field decrease with increasing Cu content. A spin reorientation behaviour has been observed in the PrCo 6.8-x Cu x Hf 0.2 compounds. The addition of Cu weakens the anisotropy of the Co sublattice, leading to an increase in the spin reorientation temperature with increasing content of Cu

Transport properties of S0.8Se16M0.2 (M = Al, Ag or Cu) system

International Nuclear Information System (INIS)

Wahab, L.A.

2003-01-01

The results are presented of a study of the electrical and optical properties of vacuum evaporated amorphous thin films in the S 0.8 Se 16 M 0.2 (M=Al, Ag or Cu) system. The activation energy and the pre-exponential factor which appear in the dc conductivity are found to be higher in case of Cu than in case of Ag and Al. The reflectance and transmission are used to measure the optical gap. The glass S 0.8 Se 16 Cu 0.2 behaves as a quasi intrinsic semiconductor (the electrical activation energy is about half of the optical gap). The electrical activation energy is about one-third of the optical gap for the chalcogenide glasses S 0.8 Se 16 Al 0.2 and S 0.8 Se 16 Ag 0.2 . The variation in the refractive index and the imaginary part of the dielectric constant with photon energy have also been reported. The influence of composition on the investigated parameters is reported

Preparation and characterizations of Ba0.8Ca0.2TiO3 by complex polymerization method (CPM)

International Nuclear Information System (INIS)

Motta, F.V.; Marques, A.P.A.; Escote, M.T.; Melo, D.M.A.; Ferreira, A.G.; Longo, E.; Leite, E.R.; Varela, J.A.

2008-01-01

Ba 0.8 Ca 0.2 TiO 3 (BCT) was prepared by the complex polymerization method (CPM) using Ba 0.8 Ca 0.2 CO 3 and [Ti[OCH(CH 3 ) 2 ] 4 as starting materials. The powders were crystallized at several temperatures from 400 to 1200 deg. C using different times (from 1 to 8 h). The phase evolution and the physical properties were characterized by X-ray diffraction, Raman and IR spectroscopy. Such results indicate that the precursor Ba 0.8 Ca 0.2 CO 3 used in the synthesis of Ba 0.8 Ca 0.2 TiO 3 promotes an effective complexation of the ions Ca 2+ in the matrix of BaTiO 3 . After heat treatment for 2 h at 600 deg. C the phase BCT was obtained with absence of the CaTiO 3 or BaCO 3 phases. The CPM is an efficient method in the synthesis of the BCT, using small reaction time and low temperature and cost for the preparation of these powders

Structural and compositional optimization of the LiNi0.8Co0.2O2 electrode by new synthesis conditions

International Nuclear Information System (INIS)

Mosqueda L, Y.; Milian P, C. R.; Pomares A, M.; Rodriguez H, J.; Perez C, E.

2012-01-01

The optimization of citrate precursor method to obtain the LiNi 0.8 Co 0.2 O 2 oxide from the thermal decomposition of the citrate precursor (NH 4 ) 3 LiNi 0.8 Co 0.2 (C 6 H 5 O 7 ) is presented. The optimization procedure consists of both the lithium atmosphere and the reaction time control during the decomposition of the citrate precursor. Were obtained and characterized two kind of the (Li l-x Ni x )(Ni 0.8 Co 0.2 )O 2 oxides, with and without optimized synthesis conditions, identified as A and B oxides, respectively. The A and B oxides are characterized by compositional, structural and electrochemical studies. The results showed that is possible to reach the ordered oxide phase at smaller reaction time if the lithium atmosphere is controlled. From the combination of the chemical analysis by Icp and the DRX Rietveld structural refinement it is possible to establish the Li, Ni(II), Ni(III) and Co(III) composition with great accuracy. The resulted structural and compositional transformations have a close relation with technological parameters of the rechargeable lithium battery using Li Ni 0.8 Co 0.2 O 2 oxide as cathode. (Author)

Electrochemical performance of Ni0.8Cu0.2/Ce0.8Gd0.2O1.9 cermet anodes with functionally graded structures for intermediate-temperature solid oxide fuel cell fueled with syngas

Science.gov (United States)

Miyake, Michihiro; Iwami, Makoto; Takeuchi, Mizue; Nishimoto, Shunsuke; Kameshima, Yoshikazu

2018-06-01

The electrochemical performance of layered Ni0.8Cu0.2/Ce0.8Gd0.2O1.9 (GDC) cermet anodes is investigated for intermediate-temperature solid oxide fuel cells (IT-SOFCs) at 600 °C using humidified (3% H2O) model syngas with a molar ratio of H2/CO = 3/2 as the fuel. From the results obtained, the electrochemical performance of the functionally graded multi-layered anodes is found to be superior to the mono-layered anodes. The test cell with a bi-layered anode consisting of 100 mass% Ni0.8Cu0.2/0 mass% GDC (10M/0E) and 70 mass% Ni0.8Cu0.2/30 mass% GDC (7M/3E) exhibits high power density. The test cell with a tri-layered anode consisting of 10M/0E, 7M/3E, and 50 mass% Ni0.8Cu0.2/50 mass% GDC (5M/5E) exhibits an even higher power density, suggesting that 10M/0E and 5M/5E layers contribute to the current collecting part and active part, respectively.

Identification of possible factors impacting dental students' ability to locate MB2 canals in maxillary molars.

Science.gov (United States)

Park, Ellen; Chehroudi, Babak; Coil, Jeffrey M

2014-05-01

This study examined the effect of the access size and straight-line path of access on third-year dental students' ability to locate a second mesiobuccal (MB2) canal in maxillary first and second molars. One hundred and six third-year dental students at one Faculty of Dentistry performed simulated root canal treatment with the aid of 2x magnification loupes on extracted teeth. A postgraduate endodontic student subsequently made a reasonable search for an untreated MB2 canal with the aid of a dental operating microscope. The mesiobuccal roots were then sectioned horizontally for determination of the canal configuration. The dental students were able to treat an MB2 canal in 15.8 percent of the teeth, but this was not associated with satisfactory access criteria. The postgraduate endodontic student identified an MB2 canal in 54.7 percent of the remaining tooth samples excluding those where the MB2 canal was found by the dental students; this represented 94.3 percent of those teeth confirmed by horizontal sectioning of the root to have an MB2 canal. The postgraduate student troughed, on average, 2.6 mm before negotiating the MB2 canal. As satisfactory access criteria and straight-line path of access did not correlate with the dental students' ability to find a second mesiobuccal canal, this result has important implications for educational goals with respect to endodontic treatment of maxillary molar teeth.

Structural phase transition and multiferroic properties of Bi0.8A0.2Fe0.8Mn0.2O3 (A = Ca, Sr)

Science.gov (United States)

Rout, Jyoshna; Choudhary, R. N. P.

2018-05-01

The multiferroic BiFeO3 and Bi0.8A0.2Fe0.8Mn0.2O3 (A = Ca, Sr) have been synthesized using direct mechanosynthesis. Detailed investigations were made on the influence of Ca-Mn and Sr-Mn co-substitutions on the structure change, electric and magnetic properties of the BFO. Rietveld refinement on the XRD pattern of the modified samples clarifies the structural transition from R3c:H (parent BiFeO3) to the biphasic structure (R3c: H + Pnma). Scanning electron micrographs confirmed the polycrystalline nature of the materials and each of the microstructure comprised of uniformly distributed grains with less porosity. The dielectric measurements reveal that enhancement in dielectric properties due to the reduction of oxygen vacancies by substitutional ions. Studies of frequency-dependence of impedance and related parameters exhibit that the electrical properties of the materials are strongly dependent on temperature, and bear a good correlation with its microstructure. The bulk resistance (evaluated from impedance studies) is found to decrease with increasing temperature for all the samples. The alternating current (ac) conductivity spectra show a typical signature of an ionic conducting system, and are found to obey Jonscher's universal power law. Preliminary studies of magnetic characteristics of the samples reveal enhanced magnetization for Ca-Mn co-substituted sample. The magnetoelectric coefficient as the function of applied dc magnetizing field under fixed ac magnetic field 15.368 Oe is measured and this ME coefficient αME corresponds to induction of polarization by a magnetic field.

Giant room-temperature magnetoresistance in La0.8Tb0.2MnO3 under the low magnetic fields

International Nuclear Information System (INIS)

Zhang Yingtang; Chen Ziyu; Wang Chunchang; Jie Qiu; Lue Huibin

2009-01-01

Polycrystalline perovskite La 0.8 Tb 0.2 MnO 3 (LTMO) with an orthorhombic phase was synthesized by conventional solid-state reaction. The magnetic and electric properties of La 0.8 Tb 0.2 MnO 3 were examined. The striking finding is that the material exhibits giant magnetoresistance at room temperature as high as -31.8% and -35.7% under the low magnetic fields of 100 and 1000 Oe, respectively. This result suggests that La 0.8 Tb 0.2 MnO 3 has a promising potential in future device developments

Thermal expansion of CeCu5.8Ag0.2

International Nuclear Information System (INIS)

Kuechler, R.; Gegenwart, P.; Heuser, K.; Scheidt, E.-W.; Stewart, G.R.; Steglich, F.

2005-01-01

We present low-temperature thermal expansion measurements on the heavy fermion system CeCu 5.8 Ag 0.2 , which is located at an antiferromagnetic (AF) quantum critical point (QCP). At zero magnetic field, the volume expansion coefficient divided by temperature shows a logarithmic divergence upon cooling below 1K. This temperature dependence is incompatible with the predictions of the itinerant spin-density wave theory for an AF QCP. The application of magnetic fields leads to a cross-over to Landau Fermi liquid behavior as expected for a zero-field QCP

A screen-printed Ce 0.8Sm 0.2O 1.9 film solid oxide fuel cell with a Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3- δ cathode

Science.gov (United States)

Zhang, Yaohui; Huang, Xiqiang; Lu, Zhe; Liu, Zhiguo; Ge, Xiaodong; Xu, Jiahuan; Xin, Xianshuang; Sha, Xueqing; Su, Wenhui

Screen-printing technology was developed to fabricate Ce 0.8Sm 0.2O 1.9 (SDC) electrolyte films onto porous NiO-SDC green anode substrates. After sintering at 1400 °C for 4 h, a gas-tight SDC film with a thickness of 12 μm was obtained. A novel cathode material of Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3- δ was subsequently applied onto the sintered SDC electrolyte film also by screen-printing and sintered at 970 °C for 3 h to get a single cell. A fuel cell of Ni-SDC/SDC (12 μm)/Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3- δ provides the maximum power densities of 1280, 1080, 670, 370, 180 and 73 mW cm -2 at 650, 600, 555, 505, 455 and 405 °C, respectively, using hydrogen as fuel and stationary air as oxidant. When dry methane was used as fuel, the maximum power densities are 876, 568, 346 and 114 mW cm -2 at 650, 600, 555 and 505 °C, respectively. The present fuel cell shows excellent performance at lowered temperatures.

Structural, magnetic and magnetocaloric properties of La{sub 0.8}Ca{sub 0.2−x}Na{sub x}MnO{sub 3} manganites (0≤x≤0.2)

Energy Technology Data Exchange (ETDEWEB)

Choura Maatar, S. [Laboratoire de Physique des Matériaux, Faculté des Sciences de Sfax, Sfax University, B.P. 1171, 3000 Sfax (Tunisia); M’nassri, R. [Laboratoire de Physique des Matériaux, Faculté des Sciences de Sfax, Sfax University, B.P. 1171, 3000 Sfax (Tunisia); Institut NEEL, CNRS, B.P.166, 38042 Grenoble Cedex 9 (France); Cheikhrouhou Koubaa, W., E-mail: wissem.koubaa@yahoo.fr [Laboratoire de Physique des Matériaux, Faculté des Sciences de Sfax, Sfax University, B.P. 1171, 3000 Sfax (Tunisia); Koubaa, M. [Laboratoire de Physique des Matériaux, Faculté des Sciences de Sfax, Sfax University, B.P. 1171, 3000 Sfax (Tunisia); Cheikhrouhou, A. [Laboratoire de Physique des Matériaux, Faculté des Sciences de Sfax, Sfax University, B.P. 1171, 3000 Sfax (Tunisia); Centre de Recherche en Informatique, Multimédia et Traitement Numérique des Données, Technopole de Sfax, Cité El Ons, Route de Tunis, Km 9, Sfax. B.P. 275, Sakiet Ezzit, 3021 Sfax (Tunisia)

2015-05-15

In this work, we report the effect of Na doping on the structural, magnetic and magnetocaloric properties in La{sub 0.8}Ca{sub 0.2−x}Na{sub x}MnO{sub 3} powder samples. Our polycristalline samples have been synthesized using the solid-state reaction method at high temperatures. The parent compound La{sub 0.8}Ca{sub 0.2}MnO{sub 3} crystallizes in the orthorhombic system with Pbnm space group. Na doping induces a structural transition from orthorhombic (Pbnm space group) to rhombohedral (R-3C space group) symmetry. Magnetization measurements versus temperature in a magnetic applied field of 50 mT showed that all our investigated samples display a paramagnetic-ferromagnetic transition with decreasing temperature. The Curie temperature T{sub C} increases with Na content from 240 K for x=0 to 330 K for x=0.2. A large magnetocaloric effect has been observed in all samples, the maximum entropy change, |∆S{sub M}|{sub max}, shifts to smaller values with increasing Na content, from4.56 J/kg K (x=0.05) to 2.3 J/kg K (x=0.2) under a magnetic field change ∆µ{sub 0}H of 2 T. For the same applied magnetic field of 2 T, the Relative Cooling Power (RCP) values are found to be constant around 91 J/kg. - Graphical abstract: Sodium doping induces an increase of T{sub C} from 240 K for x=0 to 330 K for x=0.2. - Highlights: • La{sub 0.8}Ca{sub 0.2−x}Na{sub x}MnO{sub 3} are synthesized using the ceramic method at high temperatures. • Na doping induces a structural transition from Pbnm to R-3C space group. • T{sub C} increases with Na content from 240 K for x=0 to 330 K for x=0.2. • RCP is constant around 91 J/kg for all compounds under 2 T.

Low-Temperature Sintering Li3Mg1.8Ca0.2NbO6 Microwave Dielectric Ceramics with LMZBS Glass

Science.gov (United States)

Wang, Gang; Zhang, Huaiwu; Liu, Cheng; Su, Hua; Jia, Lijun; Li, Jie; Huang, Xin; Gan, Gongwen

2018-05-01

Li3Mg1.8Ca0.2NbO6 ceramics doped with Li2O-MgO-ZnO-B2O3-SiO2 glass (LMZBS) were prepared via a solid-state route. The LMZBS glass effectively reduced the sintering temperature of Li3Mg1.8Ca0.2NbO6 ceramics to 950°C. The effects of the LMZBS glass on the sintering behavior, microstructures and microwave dielectric properties of Li3Mg1.8Ca0.2NbO6 ceramics are discussed in detail. Among all the LMZBS doped Li3Mg1.8Ca0.2NbO6 ceramics, the sample with 1 wt.% of LMZBS glass sintered at 950°C for 4 h exhibited good dielectric properties: ɛ r = 16.7, Q × f = 31,000 GHz (9.92 GHz), τ f = - 1.3 ppm/°C. The Li3Mg1.8Ca0.2NbO6 ceramics possessed excellent chemical compatibility with Ag electrodes, and could be applied in low temperature co-fired ceramics (LTCC) applications.

Magnetic ordering and electrical resistivity in Co0.2Zn0.8Fe2O4 spinel oxide

International Nuclear Information System (INIS)

Bhowmik, R.N.; Ranganathan, R.; Ghosh, B.; Kumar, S.; Chattopadhyay, S.

2008-01-01

We report the magnetic, Moessbauer spectroscopy and resistivity measurements in order to understand the electronic behaviour of bulk Co 0.2 Zn 0.8 Fe 2 O 4 spinel oxide. The effect of magnetic order on electrical behaviour is observed from the resistivity measurements in the absence and presence of magnetic field. The analysis of Moessbauer spectra suggests the absence of Fe 2+ ions in the system, which implies that complete hopping of charge carriers between localized Fe 3+ /Co 2+ and Fe 2+ /Co 3+ pair of ions in B sublattice is not the favourable mechanism in Co 0.2 Zn 0.8 Fe 2 O 4 . We suggest that electrical behaviour of the present sample may be consistent with a model of fractional charge transfer via Fe B 3+ -O 2- -Co B 2+ superexchange path

Electrochemical characterization of La0.6Ca0.4Fe0.8Ni0.2O3 cathode on Ce0.8Gd0.2O1.9 electrolyte for IT-SOFC

DEFF Research Database (Denmark)

Ortiz-Vitoriano, N.; Bernuy-Lopez, C.; Hauch, Anne

2014-01-01

For Solid Oxide Fuel Cells (SOFCs) to become an economically attractive energy conversion technology, suitable materials and structures which enable operation at lower temperatures, while retaining high cell performance, must be developed. Recently, the perovskitetype La0.6Ca0.4Fe0.8Ni0.2O3 oxide...... has shown potential as an intermediate temperature SOFC cathode. An equivalent circuit describing the cathode polarization resistances was constructed from analyzing impedance spectra recorded at different temperatures in oxygen. A competitive electrode polarization resistance is reported...... for this oxygen electrode using a Ce0.8Gd0.2O1.9 electrolyte, determined by impedance spectroscopy studies of symmetrical cells sintered at 800 _C and 1000 _C. Scanning electron microscopy (SEM) studies of the symmetrical cells revealed the absence of any reaction layer between cathode and electrolyte...

Grain refining effect of magnetic field on Mg2Ni0.8Mn0.2 hydrogen storage alloys during rapid quenching

International Nuclear Information System (INIS)

Jiang, Chenxi; Wang, Haiyan; Chen, Xiangrong; Tang, Yougen; Lu, Zhouguang; Wang, Yazhi; Liu, Zuming

2013-01-01

The effect of static magnetic field treatment for synthesis of Mg 2 Ni 0.8 Mn 0.2 alloys during rapid quenching was investigated in this paper. X-ray diffraction (XRD) and scanning electron microscope (SEM) results show that the transversal static magnetic field can effectively refine the grain size, producing nanocrystalline inside. This distinct phenomenon is probably attributed to the Lorentz force suppressing the crystallization of the hydrogen storage alloys and the thermoelectric effect. Mainly due to the grain refinement, the discharge capacity of Mg 2 Ni 0.8 Mn 0.2 alloy is raised from 79 to about 200 mA h g −1 . It is confirmed that Mg 2 Ni 0.8 Mn 0.2 alloy by magnetic field assisted approach possesses enhanced electrochemical kinetics and relatively high corrosion resistance against the alkaline solution, thus resulting in higher electrochemical properties

Comparative studies of the dielectric properties of (1−x)BiFeO{sub 3}-xNi{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} (x=0.0, 0.2, 0.5, 0.8, 1.0) multiferroic nanocomposite with their single phase BiFeO{sub 3} and Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Mani, Angom Devadatta, E-mail: angomdevadattamani@gmail.com; Soibam, Ibetombi

2017-02-15

BiFeO{sub 3} (BFO) and nickel zinc ferrite Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} (NZFO) were prepared by sol gel and auto combustion route respectively. Stoichiometric proportions were mixed to obtain the multiferroic nanocomposites having the compositional formula (1−x)BiFeO{sub 3}-x Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} (x=0.0, 0.2, 0.5, 0.8, 1.0). The phases were confirmed by XRD analyses. SEM micrographs showed the agglomerated nature of the particles with continuous grain growth in all directions. Elemental compositions were confirmed from EDAX studies. FTIR studies showed the stretching and bending vibrations of the various bonds present in the samples. The dielectric properties such as dielectric constant, ε′ and dielectric loss tangent, tanδ were studied for the spinel, perovskite and nanocomposite ferrites. Experimental result shows an increasing trend in the value of dielectric constant in going from spinel to perovskite phase. The frequency dependence of tanδ showed minimum loss for x=0.5 nanocomposite. Possible mechanisms explaining the above results were being discussed.

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

International Nuclear Information System (INIS)

Hao Sue; Sun Liang; Huang Jinxiang

2008-01-01

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

Crystal structure of superparamagnetic Mg0.2Ca0.8Fe2O4 nanoparticles synthesized by sol–gel method

International Nuclear Information System (INIS)

Escamilla-Pérez, A.M.; Cortés-Hernández, D.A.; Almanza-Robles, J.M.; Mantovani, D.; Chevallier, P.

2015-01-01

Powders of magnetic iron oxide nanoparticles (Mg 0.2 Ca 0.8 Fe 2 O 4 ) were prepared by a sol–gel method using ethylene glycol and nitrates of Fe, Ca and Mg as starting materials. Those powders were heat treated at different temperatures (573, 673, 773 and 873 K). In order to evaluate the effect of the heat treatment temperature on the nanoferrites properties, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used. It was found that the reaction products exhibit nanometric sizes and superparamagnetic behavior. It is also demonstrated that, as the heat treatment temperature increases, the particle size and the saturation magnetization of the nanoferrites are increased. - Highlights: • Mg 0.2 Ca 0.8 Fe 2 O 4 superparamagnetic nanoparticles were successfully synthesized. • Particle average sizes of Ca–Mg ferrites were within the range of 8–25 nm. • The nanoferrite treated at 873 K showed a stoichiometry close to Mg 0.2 Ca 0.8 Fe 2 O 4 . • The heat treatment temperature has a strong effect on the crystal structure. • These nanoparticles are potential materials for magnetic hyperthermia

Electronic and ionic transport in Ce0.8PrxTb0.2-xO2-δ and evaluation of performance as oxygen permeation membranes

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2012-01-01

is significantly enhanced relative to that of a Ce0.9Gd0.1O1.95-δ membrane at high oxygen activities of the permeate gas (aO2 an > 10-15) due to the enhanced electronic conductivity of the Ce0.8PrxTb0.2-xO2-δ compounds. Interference between the ionic and electronic flows has a significant positive effect......The electronic conductivity of Ce0.8PrxTb0.2-xO2-δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 to aO2 ≈ 10-17 at 700- 900 °C by means of Hebb-Wagner polarisation. The electronic conductivity of all the Ce0.8PrxTb0.2-xO2-δ compositions was significantly...... enhanced as compared to that of Ce0.9Gd0.1O1.95-δ, and its value was found to increase with increasing Pr/Tb ratio. The ionic mobility of Ce0.8PrxTb0.2-xO2-δ is similar to that of Ce1- 2δGd2δO2-δ at the same oxygen vacancy concentration. The calculated oxygen flux of a Ce0.8PrxTb0.2-xO2-δ membrane...

Effect of buffer thickness on properties of In0.8Ga0.2As/InP with two-step growth technique

International Nuclear Information System (INIS)

Zhang Tiemin; Miao Guoqing; Jin Yixin; Yu Shuzhen; Jiang Hong; Li Zhiming; Song Hang

2009-01-01

In 0.8 Ga 0.2 As was grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) on InP(1 0 0) substrate with two-step growth technique. Effect of buffer thickness on crystalline quality, surface morphology, electrical property and stress of In 0.8 Ga 0.2 As epilayer was analyzed, and properties of the In 0.8 Ga 0.2 As epilayer were characterized by X-ray diffraction, scanning electron microscopy, Hall measurements and Raman scattering. The experiments showed that the properties of the In 0.8 Ga 0.2 As epilayer had close relation to the buffer thickness and the optimum buffer thickness was about 100 nm

Nanomagnets La0.8Pb0.2(Fe0.8Co0.2)O3 assembled with a bonded surface graphene oxide: sensitive for sensing small gas molecules.

Science.gov (United States)

Bhargav, K K; Ram, S; Majumder, S B

2012-04-01

Nanocrystallites La0.8Pb0.2(Fe0.8Co0.2)O3 (LPFC) when bonded through a surface layer (carbon) in small ensembles display surface sensitive magnetism useful for biological probes, electrodes, and toxic gas sensors. A simple dispersion and hydrolysis of the salts in ethylene glycol (EG) in water is explored to form ensembles of the nanocrystallites (NCs) by combustion of a liquid precursor gel slowly in microwave at 70-80 dgrees C (apparent) in a closed container in air. In a dilute sample, the EG molecules mediate hydrolyzed species to configure in small groups in process to form a gel. Proposed models describe how a residual carbon bridges a stable bonded layer of a graphene-oxide-like hybrid structure on the LPFC-NCs in attenuating the magnetic structure. SEM images, measured from a pelletized sample which was used to study the gas sensing features in terms of the electrical resistance, describe plate shaped NCs, typically 30-60 nm widths, 60-180 nm lengths and -50 m2/g surface area (after heating at -750 degrees C). These NCs are arranged in ensembles (200-900 nm size). As per the X-ray diffraction, the plates (a Pnma orthorhombic structure) bear only small strain -0.0023 N/m2 and oxygen vacancies. The phonon and electronic bands from a bonded surface layer disappear when it is etched out slowly by heating above 550 degrees C in air. The surface layer actively promotes selective H2 gas sensor properties.

Resistance switching mechanism of La_0_._8Sr_0_._2MnO_3_−_δ thin films

International Nuclear Information System (INIS)

Luo, X.D.; Gao, R.L.; Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L.; Zhang, H.R; Sun, J.R.

2016-01-01

Effects of oxygen vacancies on the electrical transport properties of oxygen stoichiometric La_0_._8Sr_0_._2MnO_3 and oxygen-deficient La_0_._8Sr_0_._2MnO_3_−_δ films have been investigated. The result presents that the oxygen-deficient films annealed in vacuum show obvious increase of resistance and lattice parameter. With the sweeping voltage or temperature increasing, the resistance exhibits obvious bipolar switching effect, no forming process was needed. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Mn–O–Mn conduction channel due to the accumulation of oxygen vacancies under high external electric field or temperatures and hence is believed to be responsible for the bipolar resistance switching effect and the enhanced resistivity compared with oxygen stoichiometric La_0_._8Sr_0_._2MnO_3 film. These results may be important for practical applications in photoelectric or storage devices and point to a useful direction for other oxidizing materials.

Synthesis of nanocrystalline nickel-zinc ferrite (Ni0.8Zn0.2Fe2O4) thin films by chemical bath deposition method

International Nuclear Information System (INIS)

Pawar, D.K.; Pawar, S.M.; Patil, P.S.; Kolekar, S.S.

2011-01-01

Graphical abstract: Display Omitted Research highlights: → We have successfully synthesized nickel-zinc ferrite (Ni 0.8 Zn 0.2 Fe 2 O 4 ) thin films on stainless steel substrates using a low temperature chemical bath deposition method. → The surface morphological study showed the compact flakes like morphology. → The as-deposited thin films are hydrophilic (10 o o ) whereas the annealed thin films are super hydrophilic (θ o ) in nature. → Ni 0.8 Zn 0.2 Fe 2 O 4 thin films could be used in supercapacitor. - Abstract: The nickel-zinc ferrite (Ni 0.8 Zn 0.2 Fe 2 O 4 ) thin films have been successfully deposited on stainless steel substrates using a chemical bath deposition method from alkaline bath. The films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), static water contact angle and cyclic voltammetry measurements. The X-ray diffraction pattern shows that deposited Ni 0.8 Zn 0.2 Fe 2 O 4 thin films were oriented along (3 1 1) plane. The FTIR spectra showed strong absorption peaks around 600 cm -1 which are typical for cubic spinel crystal structure. SEM study revealed compact flakes like morphology having thickness ∼1.8 μm after air annealing. The annealed films were super hydrophilic in nature having a static water contact angle (θ) of 5 o .The electrochemical supercapacitor study of Ni 0.8 Zn 0.2 Fe 2 O 4 thin films has been carried out in 6 M KOH electrolyte. The values of interfacial and specific capacitances obtained were 0.0285 F cm -2 and 19 F g -1 , respectively.

Temperature-dependent impedance spectroscopy of La0.8Sr0.2FeO3 nano-crystalline material

Science.gov (United States)

Kafa, C. A.; Triyono, D.; Laysandra, H.

2017-04-01

LaFeO3 is a material with perovskite structure which electrical properties frequently investigated. Research are done due to the exhibition of excellent gas sensing behavior through resistivity comparison from the p-type semiconductor. Sr doping on LaFeO3 or La1-xSrxFeO3 are able to improve the electrical conductivity through structural modification. Using Sr dopant concentration (x) of 0.2, La0.8Sr0.2FeO3 nano-crystal pellet was synthesized. The synthesis used sol-gel method, followed by gradual heat treatment and uniaxial compaction. XRD characterization shows that the structure of the sample is Orthorhombic Perovskite. Topography of the sample by SEM reveals grain and grain boundary existence with emerging agglomeration. The electrical properties of the material, as functions of temperature and frequency, were measured by Impedance Spectroscopy method using RLC meter, for temperatures of 303-373K. Through the Nyquist plot and Bode plot, the electrical conductivity of La0.8Sr0.2FeO3 is contributed by the grain and grain boundary. Finally, the electrical permittivities of La0.8Sr0.2FeO3 are increasing with temperature increase, with the highest achieved when measured at 1 kHz frequency.

Two S-wave gap symmetry for single crystals of the superconductor BaFe1.8Co0.2As2

International Nuclear Information System (INIS)

Choi, Ki-Young; Kim, Soo Hyun; Choi, Changho; Jung, Myung-Hwa; Wang, X.F.; Chen, X.H.; Noh, Jae Dong; Lee, Sung-IK

2010-01-01

To clarify the gap structure of the iron-pnictide superconductors, we synthesized optimally doped single crystals of BaFe 1.8 Co 0.2 As 2 , which had a critical temperature, T c , of 23.6 K. The initial M-H curve was used to find the lower critical field, H c1 . The full range of the temperature dependence of H c1 was explained by using a two S-wave gap symmetry. We estimate the two gap as Δ 1 (0) = 1.64 ± 0.2 meV for the small gap and Δ 2 (0) = 6.20 ± 0.2 meV for the large gap.

Synthesis of porous LiFe0.2Mn1.8O4 with high performance for lithium-ion battery

International Nuclear Information System (INIS)

Shi, Yishan; Zhu, Shenmin; Zhu, Chengling; Li, Yao; Chen, Zhixin; Zhang, Di

2015-01-01

Highlights: • Porous LiFe 0.2 Mn 1.8 O 4 was fabricated with P123 as a template through a nitrate decomposition method • A high rate capacity and cycling stability were demonstrated when used as cathode in LIBs • This strategy is expected to fabricate other multiple metal oxides with porous structures - Abstract: A facile and effective route was developed for the fabrication of LiFe 0.2 Mn 1.8 O 4 with porous structures by using Pluronic P-123 as a soft template, based on a nitrate decomposition method. The resultant LiFe 0.2 Mn 1.8 O 4 was characterized by XRD, SEM, as well as N 2 adsorption/desorption measurements which showed a porous structure with a pore size centered at 20 nm. When used as cathode materials in lithium battery, the as-synthesized LiFe 0.2 Mn 1.8 O 4 exhibited a discharge capacity of 122 mAh g −1 at 1 C and 102 mAh g −1 at 5 C. Moreover, after 500 cycles, the capacity retention (108 mAh g −1 ) reached 88% of the initial capacity at 1 C. As compared with conventional cathode LiMn 2 O 4 , the high performance is believed to originate from the combined effects of porous structure, iron doping and highly crystalline nature of the obtained LiFe 0.2 Mn 1.8 O 4 . This strategy is expected to allow the fabrication of other multiple metal oxides with porous structures for high performance cathode materials

Topotactic reduction and phase transitions in (T,T′ La1.8Pr0.2CuO4

Directory of Open Access Journals (Sweden)

M.I. Houchati

2017-05-01

The X-ray powder diffraction data have revealed that this cuprate is crystallized with the so-called “pseudo-S” type structure, showing a monoclinic symmetry and space group A2/m. Concerning the EPR measurements, they have shown the presence of Cu2+ cation and a hyperfine structure suggesting a pronounced hybridization of the copper–oxygen bond. Finally, X-ray diffraction has demonstrated that the obtained La1.8Pr0.2CuO3.5, heated in oxygen at 420 °C, turns topotactically into La1.8Pr0.2CuO4 with a T′-type structure (I4/mmm.

Temperature compensation effects of TiO2 on Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ microwave dielectric ceramic

Science.gov (United States)

Hu, Mingzhe; Wei, Huanghe; Xiao, Lihua; Zhang, Kesheng; Hao, Yongde

2017-10-01

The crystal structure and dielectric properties of TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ microwave ceramics are investigated in the present paper. The crystal structure is probed by XRD patterns and their Rietveld refinement, results show that a single perovskite phase is formed in TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramics with the crystal structure belonging to the orthorhombic Pbnm 62 space group. Raman spectra results indicate that the B-site order-disorder structure transition is a key point to the dielectric loss of TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramics at microwave frequencies. After properly modified by TiO2, the large negative temperature coefficient of Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramic can be compensated and the optimal microwave dielectric properties can reach 𝜀r = 25.66, Qf = 18,894 GHz and TCF = -6.3 ppm/∘C when sintered at 1170∘C for 2.5 h, which manifests itself for potential use in microwave dielectric devices for modern wireless communication.

La0.8Sr0.2MnO3

KAUST Repository

Wang, Q.; Chen, A. P.; Guo, E. J.; Roldan, M. A.; Jia, Q. X.; Fitzsimmons, M. R.

2018-01-01

Using polarized neutron reflectometry, we measured the influence of elastic bending stress on the magnetization depth profile of a La0.8Sr0.2MnO3 (LSMO) epitaxial film grown on a SrTiO3 substrate. The elastic bending strain of +/- 0.03% has no obvious effect on the magnetization depth profile at saturation. This result is in stark contrast to that of (La1-xPrx)(1-y),Ca-y,MnO3 (LPCMO) films for which strain of +/- 0.01% produced dramatic changes in the magnetization profile and Curie temperature. We attribute the difference between the influence of strain on the saturation magnetization in LSMO (weak or none) and LPCMO (strong) to a difference in the ability of LSMO (weak or none) and LPCMO (strong) to phase separate. Our observation provides an upper limit of tuning LSMO saturation magnetization via elastic strain effect.

Hydrogen storage study on Ti2CrV and ZrFe1.8V0.2 composite system

International Nuclear Information System (INIS)

Banerjee, S.; Kumar, A.; Pillai, C.G.S.; Sudarsan, V.

2012-01-01

Ti 2 CrV is reported to have one of the highest hydrogen storage capacities (more than 4 wt. %) among the bcc phase transition metal alloys. It has been found from the earlier study that Ti 2 CrV alloy shows quite good hydrogen absorption property but the desorption temperature is on the higher side. The in-situ temperature programmed desorption profile shows that the hydrogen desorption starts from 120℃ and the desorption peak comes at 180℃, which is slightly high for the vehicular application. On the other hand ZrFe 1.8 V 0.2 Laves phase alloy has low hydrogen absorption capacity, but at the room temperature it can desorp all its hydrogen. The pressure composition isotherm of ZrFe 1.8 V 0.2 alloy generated during the experiment shows the typical characteristics of the room temperature reversible hydride. The in-situ temperature programmed desorption shows that the hydride can desorb all the hydrogen below room temperature

Design of Rh/Ce0.2Zr0.8O2-Al2O3 nanocomposite for ethanol steam reforming

International Nuclear Information System (INIS)

De Rogatis, Loredana; Montini, Tiziano; Casula, Maria F.; Fornasiero, Paolo

2008-01-01

Rh(1 wt.%)/Ce 0.2 Zr 0.8 O 2 (10 wt.%)-Al 2 O 3 nanocomposite has been investigated as active and thermally stable catalyst for ethanol steam reforming. Rh nanoparticles were synthesised by surfactant assisted route, using N-hexadecyl-N-(2-hydroxyethyl)-N,N-dimethyl ammonium bromide (HEAC16Br). Metal particles with average diameter of 2.1 nm were obtained at 0.53 Rh/HEAC16Br molar ratio, while increasing the amount of surfactant lead to formation of larger particles. The preformed Rh nanoparticles have been effectively embedded into a porous layer of nanocomposite oxides. Low temperature H 2 chemisorption experiments and activity data confirm that most of the Rh atoms are accessible to the reaction mixture. The Ce 0.2 Zr 0.8 O 2 mixed oxide inhibits the dehydration of ethanol to ethylene and favours the water gas shift reaction. The alumina ensures good thermal stability and high surface area of the catalyst. No significant deactivation is observed after repeated run-up and run-down experiments

Microwave properties of La{sub 0.8}Ag{sub 0.2}MnO{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Rostamnejadi, Ali [Malek Ashtar University of Technology, Electroceram Research Center, Shahin Shahr, Isfahan (Iran, Islamic Republic of)

2016-11-15

In this research, single-phase nanoparticles of La{sub 0.8}Ag{sub 0.2}MnO{sub 3} with mean particle size of 15 nm have been synthesized by sol-gel method. The microwave properties of La{sub 0.8}Ag{sub 0.2}MnO{sub 3}/paraffin nanocomposite are studied by measuring the complex permittivity and permeability in the frequency range of 1-18 GHz. The composite shows both reflection and absorption electromagnetic shielding effectiveness with maximum total value of 36 dB, which is suitable for defense and microwave radiation shielding applications at high temperatures. The electromagnetic absorption properties are described in terms of dielectric relaxation processes. (orig.)

Oxygen Nonstoichiometry and Defect Chemistry Modeling of Ce0.8Pr0.2O2-delta

OpenAIRE

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2010-01-01

The oxygen nonstoichiometry (delta) of Ce0.8Pr0.2O2−delta has been measured as a function of PO2 at temperatures between 600 and 900°C by coulometric titration and thermogravimetry. An ideal solution defect model, a regular solution model, and a defect association model, taking into account the association of reduced dopant species and oxygen vacancies, were unable to reproduce the experimental results. However, excellent agreement with the experimentally determined oxygen nonstoichiometry co...

The high-pressure structural configurations of Ca_0.2Sr_0.8Al₂Si ₂O₈ feldspar

DEFF Research Database (Denmark)

Benna, Piera; Nestola, Fabrizio; Boffa Ballaran, Tiziana

2007-01-01

Single-crystal in situ high-P X-ray diffraction was performed at P = 0.0001, 3.2, 4.4, 6.2, and 7.4 GPa on synthetic Ca0.2Sr0.8Al2Si2O8 feldspar (An20SrF80). Data collections conÞ rmed the displacive Þ rst-order triclinic I1-monoclinic I2/c phase transition at P ~4.3 GPa found in a previous high-...

Magnetic properties and tunable magneto-caloric effect in La0.8Ce0.2Fe11.5-xCoxSi1.5C0.2 (x = 0.3, 0.5, and 0.7) compounds

Science.gov (United States)

Wu, Qiming; Wang, Xiangjie; Ding, Zan; Li, Lingwei

2018-05-01

The magnetic and magneto-caloric properties in the ternary elementals doped La0.8Ce0.2Fe11.5-xCoxSi1.5C0.2 (x = 0.3, 0.5, and 0.7) compounds were studied. With the increases of Co content x, the Curie temperature TC increases and the thermal hysteresis decreases. All the compounds undergo a second-order magnetic phase transition and exhibit a considerable reversible tunable magneto-caloric effect. The values of maximum magnetic entropy change (-ΔSMmax) and the Relative Cooling Power (RCP) are kept at same high level with different Co content. Under a magnetic field change of 0-5 T, the values of -ΔSMmax for La0.8Ce0.2Fe11.5-xCoxSi1.5C0.2 are 10.5, 10.7, and 9.8 J/kg K for x = 0.3, 0.5, and 0.7, respectively. The corresponding values of RCP are 267.1, 289.9, and 290.2 J/kg.

Positron annihilation in Bi1.8Sb0.2Sr2Ca2Cu3Ox superconductor

International Nuclear Information System (INIS)

Chen Feng; Zheng Shennan; Zhang Suqun

1992-01-01

The positron lifetime and Doppler broadening line-shape parameter are measured as a function of the temperature from 78 K to 300 K for the Bi 1.8 Sb 0.2 Sr 2 Ca 2 Cu 3 O x superconductor. A decrease of both lifetime and S parameter is observed across T c . This can be interpreted by the theory of local charge transferring from the CuO layer to the BiO layer during superconducting transition. In the temperature region of normal state two anomalies are found around 165 K and 235 K. The possible origin of the observed anomalies is discussed

Structural and compositional optimization of the LiNi{sub 0.8}Co{sub 0.2}O{sub 2} electrode by new synthesis conditions

Energy Technology Data Exchange (ETDEWEB)

Mosqueda L, Y.; Milian P, C. R.; Pomares A, M.; Rodriguez H, J.; Perez C, E., E-mail: yodalgis@imre.oc.uh.cu [Havana University, Institute of Materials Science and Technology, Zapata y G, Plaza de la Revolucion, Vedado, 10400 Havana (Cuba)

2012-07-01

The optimization of citrate precursor method to obtain the LiNi{sub 0.8}Co{sub 0.2}O{sub 2} oxide from the thermal decomposition of the citrate precursor (NH{sub 4}){sub 3}LiNi{sub 0.8}Co{sub 0.2}(C{sub 6}H{sub 5}O{sub 7}) is presented. The optimization procedure consists of both the lithium atmosphere and the reaction time control during the decomposition of the citrate precursor. Were obtained and characterized two kind of the (Li{sub l-x}Ni{sub x})(Ni{sub 0.8}Co{sub 0.2})O{sub 2} oxides, with and without optimized synthesis conditions, identified as A and B oxides, respectively. The A and B oxides are characterized by compositional, structural and electrochemical studies. The results showed that is possible to reach the ordered oxide phase at smaller reaction time if the lithium atmosphere is controlled. From the combination of the chemical analysis by Icp and the DRX Rietveld structural refinement it is possible to establish the Li, Ni(II), Ni(III) and Co(III) composition with great accuracy. The resulted structural and compositional transformations have a close relation with technological parameters of the rechargeable lithium battery using Li Ni{sub 0.8}Co{sub 0.2}O{sub 2} oxide as cathode. (Author)

Ultrathin ZnO interfacial passivation layer for atomic layer deposited ZrO2 dielectric on the p-In0.2Ga0.8As substrate

Science.gov (United States)

Liu, Chen; Lü, Hongliang; Yang, Tong; Zhang, Yuming; Zhang, Yimen; Liu, Dong; Ma, Zhenqiang; Yu, Weijian; Guo, Lixin

2018-06-01

Interfacial and electrical properties were investigated on metal-oxidesemiconductor capacitors (MOSCAPs) fabricated with bilayer ZnO/ZrO2 films by atomic layer deposition (ALD) on p-In0.2Ga0.8As substrates. The ZnO passivated In0.2Ga0.8As MOSCAPs have exhibited significantly improved capacitance-voltage (C-V) characteristics with the suppressed "stretched out" effect, increased accumulation capacitance and reduced accumulation frequency dispersion as well as the lower gate leakage current. In addition, the interface trap density (Dit) estimated by the Terman method was decreased dramatically for ZnO passivated p-In0.2Ga0.8As. The inherent mechanism is attributed to the fact that an ultrathin ZnO IPL employed by ALD prior to ZrO2 dielectric deposition can effectively suppress the formation of defect-related low-k oxides and As-As dimers at the interface, thus effectively improving the interface quality by largely removing the border traps aligned near the valence band edge of the p-In0.2Ga0.8As substrate.

Study of the Effect of (U0.8Pu0.2O2 Uranium–Plutonium Mixed Fuel Fission Products on a Living Organism

Directory of Open Access Journals (Sweden)

Ayagoz Baimukhanova

2016-08-01

Full Text Available The article describes the results of experiments conducted on pigs to determine the effect of plutonium, which is the most radiotoxic and highly active element in the range of mixed fuel (U0.8Pu0.2O2 fission products, on living organisms. The results will allow empirical prediction of the emergency plutonium radiation dose for various organs and tissues of humans in case of an accident in a reactor running on mixed fuel (U0.8Pu0.2O2.

Giant room-temperature magnetoresistance in La{sub 0.8}Tb{sub 0.2}MnO{sub 3} under the low magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Zhang Yingtang [Physics of Department, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080 (China); School of Material Science and Engineering, Shaanxi University of Technology, Hanzhong 723003 (China)], E-mail: zhangyingtang76@sina.com; Chen Ziyu [Physics of Department, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)], E-mail: chenzy@buaa.edu.cn; Wang Chunchang; Jie Qiu; Lue Huibin [Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080 (China)

2009-05-15

Polycrystalline perovskite La{sub 0.8}Tb{sub 0.2}MnO{sub 3} (LTMO) with an orthorhombic phase was synthesized by conventional solid-state reaction. The magnetic and electric properties of La{sub 0.8}Tb{sub 0.2}MnO{sub 3} were examined. The striking finding is that the material exhibits giant magnetoresistance at room temperature as high as -31.8% and -35.7% under the low magnetic fields of 100 and 1000 Oe, respectively. This result suggests that La{sub 0.8}Tb{sub 0.2}MnO{sub 3} has a promising potential in future device developments.

Co-precipitation in aqueous medium of La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} via inorganic precursors

Energy Technology Data Exchange (ETDEWEB)

Pelosato, Renato; Cristiani, Cinzia; Dotelli, Giovanni; Latorrata, Saverio; Zampori, Luca [CMIC - Dipartimento di Chimica, Materiali e Ingegneria Chimica ' ' G. Natta' ' , Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133 Milano (Italy); Ruffo, Riccardo [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy)

2010-12-15

A simple and inexpensive co-precipitation route in aqueous medium is proposed to prepare La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 02}O{sub 3-{delta}} ionic conductor (LSGM). Different synthetic procedures and operating parameters (i.e. nature and amount of the precipitating agents, HNO{sub 3} addition and temperature) have been evaluated in order to underline their influence on the composition and microstructure of the final phase. Intermediate and final products were characterized by Thermal-Gravimetry, IR-spectroscopy, X-ray Powder Diffraction, Rietveld analysis and Scanning Electron Microscopy. The electrical properties were measured by Impedance Spectroscopy in the temperature range 250-800 C. Slight variations of the synthetic procedure (such as precipitating agent amount or no HNO{sub 3} addition) have a considerable and detrimental effect on the ions losses and the subsequent achievement of the final phase. The use NH{sub 4}OH as an alternative precipitating agent is dramatically disadvantageous. Ions losses during precipitation must be controlled (i) to avoid understoichiometry in the LSGM phase and (ii) to prevent the formation of large amounts of secondary phases. In fact, both affect the total electrical conductivity. The use of large excess of (NH{sub 4}){sub 2}CO{sub 3} precipitating agent and the addition of HNO{sub 3} lead to the best material characterized by a rhombohedral structure, small amount of side phases, a relative density of 98% and a total conductivity of 6.44 x 10{sup -2} S cm{sup -1} at 800 C and 1.13 x 10{sup -2} S cm{sup -1} at 600 C. (author)

Structural investigation and microwave characteristics of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing materials

Energy Technology Data Exchange (ETDEWEB)

Manaf, Azwar [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Indonesia of University (Indonesia); Adi, Wisnu Ari, E-mail: dwisnuaa@batan.go.id [Center for Technology of Nuclear Industry Material, National Nuclear Energy Agency (Indonesia)

2014-03-24

Synthesis and characterization of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing material by mechanical alloying process has been performed. The absorbing material was prepared by oxide materials, namely BaCO{sub 3}, La{sub 2}O{sub 3}, TiO{sub 2}, Fe{sub 2}O{sub 3}, and MnCO{sub 3}. The mixture was milled for 10 h and then sintered at a temperature of 1000 ° C for 10 h. The refinement results of x-ray diffraction pattern of lanthanum manganite substituted with barium showed that the sample consisted of two phases, namely, La{sub 0.9125}MnO{sub 3} phase which has a structure monoclinic (I12/a1) with lattice parameters a = 5.527(1) Å, b = 5.572(1) Å and c = 7.810(1) Å, α = γ = 90° and β = 89.88(5)°, the unit cell volume of V = 240.57(8) Å{sup 3}, and the atomic density of ρ = 6.238 gr.cm{sup −3}. The microstructure analyses showed that the particle shapes was polygonal with the varied particle sizes of 1 ∼ 3 μm distributed homogeneously on the surface of the samples. The results of the electromagnetic wave absorption curve analysis by using a vector network analyzer (VNA) showed that the sample can absorb microwaves in the frequency range of 8-15 GHz with a very wide absorption bandwidth. It indicates that the as prepared absorber presents potential absorbing property in X and Ku-band. We concluded that the (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} material can be applied as a candidate absorber material of microwaves or electromagnetic wave.

Tissue factor-factor VIIa-specific up-regulation of IL-8 expression in MDA-MB-231 cells is mediated by PAR-2 and results in increased cell migration

DEFF Research Database (Denmark)

Hjortoe, Gertrud M; Petersen, Lars C; Albrektsen, Tatjana

2004-01-01

Tissue factor (TF), the cellular receptor for factor VIIa (FVIIa), besides initiating blood coagulation, is believed to play an important role in tissue repair, inflammation, angiogenesis, and tumor metastasis. Like TF, the chemokine interleukin-8 (IL-8) is shown to play a critical role...... in these processes. To elucidate the potential mechanisms by which TF contributes to tumor invasion and metastasis, we investigated the effect of FVIIa on IL-8 expression and cell migration in a breast carcinoma cell line, MDA-MB-231, a cell line that constitutively expresses abundant TF. Expression of IL-8 m......RNA in MDA-MB-231 cells was markedly up-regulated by plasma concentrations of FVII or an equivalent concentration of FVIIa (10 nM). Neither thrombin nor other proteases involved in hemostasis were effective in stimulating IL-8 in these cells. Increased transcriptional activation of the IL-8 gene...

Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

KAUST Repository

Jeon, Sungil

2013-05-01

The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert\\'s law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Hydrogen permeation properties of Pd-coated V89.8Cr 10Y0.2 alloy membrane using WGS reaction gases

KAUST Repository

Jeon, Sungil; Park, Junghoon

2013-01-01

The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated V89.8Cr10Y0.2 alloy membrane. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 6.26 ml/min/cm2 for a Pd-coated V 89.8Cr10Y0.2 alloy membrane (thick: 0.5 mm) using pure hydrogen as feed gas. Also, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure at constant pressure when H 2/CO2 and H2/CO2/H2S mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert's law in different feed conditions. It was found from XRD and SEM results after permeation test that the Pd-coated V89.8Cr 10Y0.2 alloy membrane had good stability and durability for various mixture feeding conditions. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Magnetocaloric effect in the La0.8Ce0.2Fe11.4-xCoxSi1.6 compounds

International Nuclear Information System (INIS)

Wang, G.F.; Song, L.; Li, F.A.; Ou, Z.Q.; Tegus, O.; Brueck, E.; Buschow, K.H.J.

2009-01-01

The effects of substitution of Co for Fe on the magnetic and magnetocaloric properties of La 0.8 Ce 0.2 Fe 11.4-x Co x Si 1.6 (0, 0.2, 0.4, 0.6, 0.8 and 1.0) compounds have been investigated. X-ray diffraction shows that all compounds crystallize in the NaZn 13 -type structure. Magnetic measurements show that the Curie temperature (T C ) can be tuned between 184 and 294 K by changing the Co content from 0 to 1. A field-induced methamagnetic transition occurs in samples with x=0, 0.2 and 0.4. The magnetic entropy changes of the compounds have been determined from the isothermal magnetization measurements by using the Maxwell relation.

Al{sub 0.2}Ga{sub 0.8}As X-ray photodiodes for X-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Whitaker, M.D.C., E-mail: M.Whitaker@sussex.ac.uk; Lioliou, G.; Butera, S.; Barnett, A.M.

2016-12-21

Three custom-made Al{sub 0.2}Ga{sub 0.8}As p-i-n mesa X-ray photodiodes (200 µm diameter, 3 µm i layer) were electrically characterised and investigated for their response to illumination with soft X-rays from an {sup 55}Fe radioisotope X-ray source (Mn Kα = 5.9 keV; Mn Kβ = 6.49 keV). The AlGaAs photodiodes were shown to be suitable for photon counting X-ray spectroscopy at room temperature. When coupled to a custom-made low-noise charge-sensitive preamplifier, a mean energy resolution (as quantified by the full width at half maximum of the 5.9 keV photopeak) of 1.24 keV was measured at room temperature. Parameters such as the depletion width (1.92 µm at 10 V), charge trapping noise (61.7 e{sup −} rms ENC at 5 V, negligible at 10 V) and the electronic noise components (known dielectric noise (63.4 e{sup −} rms), series white noise (27.7 e{sup −} rms), parallel white noise (9.5 e{sup −} rms) and 1/f series noise (2.2 e{sup −} rms) at 10 V reverse bias) affecting the achieved energy resolution were computed. The estimated charge trapping noise and mean energy resolution were compared to similar materials (e.g. Al{sub 0.8}Ga{sub 0.2}As) previously reported, and discussed. These results are the first demonstration of photon counting X-ray spectroscopy with Al{sub 0.2}Ga{sub 0.8}As reported to date.

Dielectric Relaxation Behavior of Bismuth Doped (Ba0.2Sr0.8 TiO3 Ceramics

Directory of Open Access Journals (Sweden)

Baptista, J. L.

1999-12-01

Full Text Available The dielectric properties of bismuth doped (Ba0.2Sr0.8TiO3 ceramics are investigated. The temperature dependence of the dielectric permittivity and loss factor were measured from 102 to 106Hz in the temperature range 12-320K. As the amount of Bi increases, the ferroelectric-paraelectric phase transition gets diffused and relaxed. In addition to this ferroelectric-paraelectric phase transition, other two sets of dielectric anomalies, located at 50-100K and 200-300K respectively, are also found. The possible relaxation mechanisms are briefly discussed.Las propiedades dieléctricas de cerámicos dopados con bismuto son investigadas. La dependencia con la temperatura de la permitividad dieléctrica y el factor de pérdidas se midieron entre 02 y 106Hz en el rango de temperatura 12-320K. Con el aumento del contenido en Bi, la transición de fase ferroeléctrica-paraléctrica se hace difusa y reloja. Junto a esta transición de fase los conjuntos de anomalías dieléctricas, localizados a 50-100k y 200-300k respectivamente, también se encontraron. Se discute brevemente los posibles mecanismos de relajación.

Lattice location studies of deuterium in Pdsub(0.8)Ausub(0.2) and Ta crystals by ion channeling

International Nuclear Information System (INIS)

Takahashi, J.; Yamaguchi, S.; Koiwa, M.; Fujino, Y.; Yoshinari, O.; Hirabayashi, M.

1978-01-01

The channelling of 300 to 400 KeV deuterons combined with the D(d,p)T reaction has been used to study the lattice location of deuterium in a fcc crystal of (Pdsub(0.8)Ausub(0.2))Dsub(0.04) and a bcc crystal of TaDsub(0.10). The channelling angular distributions are measured for , , axial and brace 100 brace, brace 110 brace, brace 111 brace planar directions. It is concluded that deuterium in Pdsub(0.8)Ausub(0.2) occupies the octahedral interstice of the fcc lattice, while that in Ta occupies the tetrahedral interstice of the bcc lattice. (author)

Band Offset Measurements in Atomic-Layer-Deposited Al2O3/Zn0.8Al0.2O Heterojunction Studied by X-ray Photoelectron Spectroscopy.

Science.gov (United States)

Yan, Baojun; Liu, Shulin; Heng, Yuekun; Yang, Yuzhen; Yu, Yang; Wen, Kaile

2017-12-01

Pure aluminum oxide (Al 2 O 3 ) and zinc aluminum oxide (Zn x Al 1-x O) thin films were deposited by atomic layer deposition (ALD). The microstructure and optical band gaps (E g ) of the Zn x Al 1-x O (0.2 ≤ x ≤ 1) films were studied by X-ray diffractometer and Tauc method. The band offsets and alignment of atomic-layer-deposited Al 2 O 3 /Zn 0.8 Al 0.2 O heterojunction were investigated in detail using charge-corrected X-ray photoelectron spectroscopy. In this work, different methodologies were adopted to recover the actual position of the core levels in insulator materials which were easily affected by differential charging phenomena. Valence band offset (ΔE V ) and conduction band offset (ΔE C ) for the interface of the Al 2 O 3 /Zn 0.8 Al 0.2 O heterojunction have been constructed. An accurate value of ΔE V  = 0.82 ± 0.12 eV was obtained from various combinations of core levels of heterojunction with varied Al 2 O 3 thickness. Given the experimental E g of 6.8 eV for Al 2 O 3 and 5.29 eV for Zn 0.8 Al 0.2 O, a type-I heterojunction with a ΔE C of 0.69 ± 0.12 eV was found. The precise determination of the band alignment of Al 2 O 3 /Zn 0.8 Al 0.2 O heterojunction is of particular importance for gaining insight to the design of various electronic devices based on such heterointerface.

Giant magnetoresistance and magnetostriction in Mn1.8Co0.2Sb

International Nuclear Information System (INIS)

Kushwaha, Pallavi; Lakhani, Archna; Rawat, R.

2007-01-01

We have studied the first order ferrimagnetic (FRI) to antiferromagnetic (AFM) transition in Mn l.8 Co 0.2 Sb by resistivity, magneto resistance and magnetostriction. With the application of magnetic field FRI to AFM transition temperature (T N ) decreases monotonically and hysteresis across the transition increases. Below T N FRI to AFM transition can be induced with the application of magnetic field which results in giant magnetoresistance and magnetostriction. The magnetostriction is found to be anomalous in this compound showing a small negative minimum close to critical field required for AFM to FRI transition. (author)

Electrochemical synthesis of nanoplatelets-like CuS0.2Se0.8 thin film for photoluminescence applications

Directory of Open Access Journals (Sweden)

Sharma A. K.

2015-06-01

Full Text Available Copper sulfide-selenide (CuS0.2Se0.8 thin films were deposited on FTO coated glass substrate (fluorine doped tin oxide and stainless steel substrates using electrodeposition technique. Deposited thin films were characterized using different characterization techniques viz. X-ray diffraction (XRD, scanning electron microscopy (SEM, UV-Vis spectroscopy, photoluminescence spectroscopy and surface wettability. XRD study showed polycrystalline nature with cubic phase of the films. Scanning electron microscopy showed that the surface area of the substrate was covered by the nanoplatelets structure of a thickness of 140 to 150 nm and optical study showed that the direct band gap was ~1.90 eV. Surface wettability showed hydrophobic nature of the CuS0.2Se0.8 thin films.

Calorimetric investigation into interaction in Zr0.8Ti0.2CrFe-H2 system

International Nuclear Information System (INIS)

Sirotina, R.A.; Verbetskij, V.N.

1993-01-01

For studying Zr 0.8 Ti 0.2 CrFe-H 2 system is applied the calorimetric method with usage of the Tian-Calve type calorimeter. It is shown that up to 488 K in the system there are three characteristic regions: α (hydrogen solution in an intermetallic compounds (IMC)), β (hydrogen solution in a hydride) and α + β (region of coexistence of two phases). Temperature 448 K is near to critical one, when exceeding of which exists only hydrogen solution in a metal matrix. Pressure dependence of hydrogen content in IMC is described satisfactorily by a linear equation

Wolf-Hirschhorn (4p-) syndrome: prenatal diagnosis, molecular cytogenetic characterization and association with a 1.2-Mb microduplication at 8p22-p21.3 and a 1.1-Mb microduplication at 10p15.3 in a fetus with an apparently pure 4p deletion.

Science.gov (United States)

Chen, Chih-Ping; Su, Yi-Ning; Chen, Yi-Yung; Su, Jun-Wei; Chern, Schu-Rern; Chen, Yu-Ting; Chen, Wen-Lin; Chen, Li-Feng; Wang, Wayseen

2011-12-01

To present prenatal diagnosis and molecular cytogenetic characterization of Wolf-Hirschhorn syndrome (WHS) associated with microduplications at 8p and 10p in a fetus with an apparently pure 4p deletion. A 35-year-old gravida 2, para 1 woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Her husband was 38 years of age. There was no family history of congenital malformations. Amniocentesis revealed a karyotype of 46,XY,del(4p16.1). The parental karyotypes were normal. Array comparative genomic hybridization (aCGH) analysis revealed a 6.5-Mb deletion at 4p16.3-p16.1, a 1.2-Mb microduplication at 8p22-p21.3, and a 1.1-Mb microduplication at 10p15.3, or arr cgh 4p16.3p16.1 (0-6,531,998 bp)×1, 8p22p21.3 (18,705,388-19,940,445 bp)×3, 10p15.3 (0-1,105,065 bp)×3. Polymorphic DNA marker analysis confirmed a paternal origin of 4p deletion. Prenatal ultrasound revealed facial dysmorphism and hypospadias. The aCGH analysis of the parents revealed no genomic imbalance. Fluorescence in situ hybridization study showed an unbalanced reciprocal translocation between chromosomes 4 and 10 at bands 4p16.1 and 10p15.3. The cytogenetic result, thus, was 46,XY,der(4)t(4;10)(p16.1;p15.3),dup(8)(p21.3p22). The parents elected to terminate the pregnancy, and a 470-g malformed fetus was delivered. The present case provides evidence that an apparently pure 4p deletion can be associated with subtle chromosome imbalances in other chromosomes. Copyright © 2011. Published by Elsevier B.V.

Structural relaxation in the magnetically treated glass ceramic Bi1.8Pb0.2Sr2CaCu2Ox

International Nuclear Information System (INIS)

Alekseenko, V.I.; Volkova, G.K.; Konstanminova, T.E.; Nosolev, I.K.; Popova, I.B.

1994-01-01

Structure relaxation in Bi 1.8 Pb 0.2 Sr 2 CaCu 2 O x amorphous glass ceramics after the treatment using weak pulse magnetic field is studied using microindentation, X-ray structure analysis and inner friction techniques. Structure relaxation after substance treatment using pulse magnetic field is detected to occur at room temperature and to result in its strengthening (increase of microhardness-H v ) and in reduction of inner microstress level.9 refs., 4 figs

Electronic and Ionic Transport in Ce0.8PrxTb0.2−xO2−δ and Evaluation of Performance as Oxygen Permeation Membranes

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2012-01-01

to that of Ce0.9Gd0.1O1.95−δ, and was found to increase with increasing Pr/Tb ratio. The oxide ion mobility in Ce0.8PrxTb0.2−xO2−δ is similar to that in Ce1−2δGd2δO2−δ at the same oxygen vacancy concentration. Based on the measured ionic and electronic conductivities, fluxes through thin film Ce0.8PrxTb0.2−xO2......The electronic conductivity of Ce0.8PrxTb0.2−xO2−δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 – 10−17 at 700–900°C by Hebb-Wagner polarization. The electronic conductivity of all the Ce0.8PrxTb0.2−xO2−δ compositions was significantly enhanced as compared......−δ membranes were calculated. Calculated fluxes exceed 10 Nml min−1 cm−2 under oxyfuel relevant conditions (T = 800°C, aO2,permeate side = 10−3). Hence, in terms of transport properties, these materials are promising for this application. Interference between the ionic and electronic flows has...

Tritium release in Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} ceramics

Energy Technology Data Exchange (ETDEWEB)

Zhao, Linjie, E-mail: zhaolinjie1989@163.com; Long, Xinggui, E-mail: xingguil@caep.cn; Peng, Shuming, E-mail: pengshuming@caep.cn; Chen, Xiaojun; Xiao, Chengjian; Ran, Guangming; Li, Jiamao

2016-12-15

Li{sub 4+x}Si{sub 1−x}Al{sub x}O{sub 4} solid solution materials, which were designed as the advanced tritium breeders, were obtained by indirect solid state reactions. The behaviors of tritium release from Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} powders were investigated by temperature programmed desorption. The tritium release curves show different characteristics for the Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} ceramics. The main tritium release peak in the Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} powders is at approximately 600 °C after a high dose irradiation. Moreover, the temperature of the tritium release from Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} was lower than that of the release from Li{sub 4}SiO{sub 4}. This suggests a possible advantage to using the solid solutions as the advanced tritium breeding materials.

Crystal structure of superparamagnetic Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4} nanoparticles synthesized by sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Escamilla-Pérez, A.M., E-mail: angel.mep@gmail.com [Cinvestav-Unidad Saltillo, Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Cortés-Hernández, D.A., E-mail: dora.cortes@cinvestav.edu.mx [Cinvestav-Unidad Saltillo, Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Almanza-Robles, J.M. [Cinvestav-Unidad Saltillo, Industria Metalúrgica No. 1062, Parque Industrial Saltillo-Ramos Arizpe, C.P. 25900, Ramos Arizpe, Coahuila (Mexico); Mantovani, D.; Chevallier, P. [Laboratory for Biomaterials and Bioengineering, Department of Materials Engineering and University Hospital Research Center, Laval University, Quebec City, QC (Canada)

2015-01-15

Powders of magnetic iron oxide nanoparticles (Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4}) were prepared by a sol–gel method using ethylene glycol and nitrates of Fe, Ca and Mg as starting materials. Those powders were heat treated at different temperatures (573, 673, 773 and 873 K). In order to evaluate the effect of the heat treatment temperature on the nanoferrites properties, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used. It was found that the reaction products exhibit nanometric sizes and superparamagnetic behavior. It is also demonstrated that, as the heat treatment temperature increases, the particle size and the saturation magnetization of the nanoferrites are increased. - Highlights: • Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4} superparamagnetic nanoparticles were successfully synthesized. • Particle average sizes of Ca–Mg ferrites were within the range of 8–25 nm. • The nanoferrite treated at 873 K showed a stoichiometry close to Mg{sub 0.2}Ca{sub 0.8}Fe{sub 2}O{sub 4}. • The heat treatment temperature has a strong effect on the crystal structure. • These nanoparticles are potential materials for magnetic hyperthermia.

Minimal Blocking Sets in PG(2, 8) and Maximal Partial Spreads in PG(3, 8)

DEFF Research Database (Denmark)

Barat, Janos

2004-01-01

We prove that PG(2, 8) does not contain minimal blocking sets of size 14. Using this result we prove that 58 is the largest size for a maximal partial spread of PG(3, 8). This supports the conjecture that q2-q+ 2 is the largest size for a maximal partial spread of PG(3, q), q>7....

Synthesis and Characterization of Polyol-Assisted Nano Cu0.2Ni0.2Sn0.2Ba0.4 Fe2O4 by a Wet Hydroxyl Route

Science.gov (United States)

Pavithradevi, S.; Suriyanarayanan, N.; Boobalan, T.; Velumani, S.; Chandramohan, M.; Manivel Raja, M.

2017-08-01

Nanocrystalline spinel ferrite of composition Cu0.2Ni0.2Sn0.2Ba0.4 Fe2O4 has been synthesized by a wet hydroxyl chemical route in ethylene glycol as chelating agent and sodium hydroxide as precipitator at pH 8. Ethylene glycol has been used as the medium which serves as the solvent as well as a complexing agent. The synthesized particles are annealed at temperatures of 350°C, 700°C, and 1050°C. Thermogravimetric (TG) analysis confirms that at 240°C, ethylene glycol has evaporated completely, and a stable phase is formed above 670°C. Fourier transform infrared (FT-IR) spectroscopy of mixed Cu0.2Ni0.2Sn0.2Ba0.4 ferrite nanoparticles like as synthesized and annealed at 1050°C are recorded between 400 cm-1 and 4000 cm-1. FT-IR appraises the structural formation of Cu0.2Ni0.2Sn0.2Ba0.4 Fe2O4 between the as-synthesized sample and the sample annealed at 1050°C. Structural characterizations of all the samples are carried out by x-ray diffraction (XRD) technique. XRD reveals that the particle size increases with the increase in annealing temperatures. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirms that the particles are flaky and spherical with the crystallite size in the range of 11-27 nm. The decrement of dielectric properties, like dielectric constant and dielectric loss, with the increment of frequency as seen in all the samples is an usual dielectric behavior of spinel ferrites. The lack of net magnetization is noticed immediately when the applied magnetic field is removed which prompts superparamagnetic behavior, as seen in all the samples.

Synthesis of nanocrystalline nickel-zinc ferrite (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) thin films by chemical bath deposition method

Energy Technology Data Exchange (ETDEWEB)

Pawar, D.K. [Department of Chemistry, Shivaji University, Kolhapur 416 004 (M.S.) (India); Pawar, S.M. [Department of Materials Science and Engineering, Chonnam National University, 500 757 (Korea, Republic of); Patil, P.S. [Department of Physics, Shivaji University, Kolhapur 416 004 (M.S.) (India); Kolekar, S.S., E-mail: kolekarss2003@yahoo.co.in [Department of Chemistry, Shivaji University, Kolhapur 416 004 (M.S.) (India)

2011-02-24

Graphical abstract: Display Omitted Research highlights: > We have successfully synthesized nickel-zinc ferrite (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) thin films on stainless steel substrates using a low temperature chemical bath deposition method. > The surface morphological study showed the compact flakes like morphology. > The as-deposited thin films are hydrophilic (10{sup o} < {theta} < 90{sup o}) whereas the annealed thin films are super hydrophilic ({theta} < 10{sup o}) in nature. > Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} thin films could be used in supercapacitor. - Abstract: The nickel-zinc ferrite (Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) thin films have been successfully deposited on stainless steel substrates using a chemical bath deposition method from alkaline bath. The films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), static water contact angle and cyclic voltammetry measurements. The X-ray diffraction pattern shows that deposited Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} thin films were oriented along (3 1 1) plane. The FTIR spectra showed strong absorption peaks around 600 cm{sup -1} which are typical for cubic spinel crystal structure. SEM study revealed compact flakes like morphology having thickness {approx}1.8 {mu}m after air annealing. The annealed films were super hydrophilic in nature having a static water contact angle ({theta}) of 5{sup o}.The electrochemical supercapacitor study of Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} thin films has been carried out in 6 M KOH electrolyte. The values of interfacial and specific capacitances obtained were 0.0285 F cm{sup -2} and 19 F g{sup -1}, respectively.

Growth of solid solutions with colquiriite structure LiCa0,2Sr0,8AlF6: Ce3+

International Nuclear Information System (INIS)

Shavelev, A A; Nizamutdinov, A S; Semashko, V V; Marisov, M A

2014-01-01

Aim of this work were experiments on growing new materials based on fluoride crystals with the colquiriite structure LiSr 0,8 Ca 0,2 F 6 , as well as the study of their phase composition. It is shown that for a series of crystals LiSr 0,8 Ca 0,2 F 6 distribution of reflections observed corresponds to the colquiriite structure, and the dependence of the lattice constant in the transition from LiCaAlF 6 crystal to LiSrAlF 6 crystal is linear. Also it found that absorption coefficient in mixed samples is much larger than in not mixed

Magnetic ordering and electrical resistivity in Co{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4} spinel oxide

Energy Technology Data Exchange (ETDEWEB)

Bhowmik, R.N. [Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700065 (India)], E-mail: rabindranath.bhowmik@saha.ac.in; Ranganathan, R. [Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700065 (India); Ghosh, B.; Kumar, S. [Department of Physics, Jadavpur University, Kolkata 700 032 (India); Chattopadhyay, S. [Department of Physics, University of Calcutta, 92, A.P.C. Road, Kolkata 700009 (India)

2008-05-29

We report the magnetic, Moessbauer spectroscopy and resistivity measurements in order to understand the electronic behaviour of bulk Co{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4} spinel oxide. The effect of magnetic order on electrical behaviour is observed from the resistivity measurements in the absence and presence of magnetic field. The analysis of Moessbauer spectra suggests the absence of Fe{sup 2+} ions in the system, which implies that complete hopping of charge carriers between localized Fe{sup 3+}/Co{sup 2+} and Fe{sup 2+}/Co{sup 3+} pair of ions in B sublattice is not the favourable mechanism in Co{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4}. We suggest that electrical behaviour of the present sample may be consistent with a model of fractional charge transfer via Fe{sub B}{sup 3+}-O{sup 2-}-Co{sub B}{sup 2+} superexchange path.

Deactivation Studies of Rh/Ce0.8Zr0.2O2 Catalysts in Low Temperature Ethanol Steam Reforming

Energy Technology Data Exchange (ETDEWEB)

Platon, Alex; Roh, Hyun-Seog; King, David L.; Wang, Yong

2007-10-30

Rapid deactivation of Rh/Ce0.8Zr0.2O2 catalysts in low temperature ethanol steam reforming was studied. A significant build-up of carbonaceous intermediate, instead of carbon deposit, was observed at a lower reaction temperature which was attributed to the rapid catalyst deactivation. Co-feed experiments indicated that acetone and ethylene caused more severe catalyst deactivation than other oxygenates such as acidic acid and acetaldehyde.

Resistance switching mechanism of La{sub 0.8}Sr{sub 0.2}MnO{sub 3−δ} thin films

Energy Technology Data Exchange (ETDEWEB)

Luo, X.D. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Gao, R.L., E-mail: gaorongli2008@163.com [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Zhang, H.R; Sun, J.R. [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Science, Beijing 100190 (China)

2016-02-15

Effects of oxygen vacancies on the electrical transport properties of oxygen stoichiometric La{sub 0.8}Sr{sub 0.2}MnO{sub 3} and oxygen-deficient La{sub 0.8}Sr{sub 0.2}MnO{sub 3−δ} films have been investigated. The result presents that the oxygen-deficient films annealed in vacuum show obvious increase of resistance and lattice parameter. With the sweeping voltage or temperature increasing, the resistance exhibits obvious bipolar switching effect, no forming process was needed. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Mn–O–Mn conduction channel due to the accumulation of oxygen vacancies under high external electric field or temperatures and hence is believed to be responsible for the bipolar resistance switching effect and the enhanced resistivity compared with oxygen stoichiometric La{sub 0.8}Sr{sub 0.2}MnO{sub 3} film. These results may be important for practical applications in photoelectric or storage devices and point to a useful direction for other oxidizing materials.

Ferroelectric switching in epitaxial PbZr0.2Ti0.8O3/ZnO/GaN heterostructures

Science.gov (United States)

Wang, Juan; Salev, Pavel; Grigoriev, Alexei

As a wide-bandgap semiconductor, ZnO has gained substantial interest due to its favorable properties including high electron mobility, strong room-temperature luminescence, etc. The main obstacle of its application is the lack of reproducible and low-resistivity p-type ZnO. P-type doping of ZnO through the interface charge injection, which can be achieved by the polarization switching of ferroelectric films, is a tempting solution. We explored ferroelectric switching behavior of PbZr0.2Ti0.8O3/ZnO/GaN heterostructures epitaxially grown on Sapphire substrates by RF sputtering. The electrical measurements of Pt/PbZr0.2Ti0.8O3/ZnO/GaN ferroelectric-semiconductor capacitors revealed unusual behavior that is a combination of polarization switching and a diode I-V characteristics.

Superconductivity and photoacoustic properties of sintered La/sub 1.8/Sr/sub 0.2/CuO/sub 4/

International Nuclear Information System (INIS)

Sawan, Y.; Abu-Zeid, M.; Yousef, Y.A.

1987-01-01

In this paper the superconductivity transition properties of La/sub 1.8/Sr/sub 0.2/CuO/sub 4/ are investigated by resistivity and photo-acoustic measurements on samples prepared at different thermal prehistories. Samples with onset transition temperature of 40K and zero resistance at 35 K is detected at ambient pressure. The recent discovery of high T/sub c/ superconductivity up to 35 K in the La-Ba-Cu-O system was followed by rapid enthusiasm and intensive investigations in this field. The effect of thermal prehistory on the superconducting properties of La/sub 1.8/Sr/sub 0.2/CuO/sub 4/ and the photoacoustic characteristics of both the prepared superconducting materials as well as that of the initial starting oxides are presented

Superconducting single X-ray photon detector based on W0.8Si0.2

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Xiaofu Zhang

2016-11-01

Full Text Available We fabricated a superconducting single X-ray photon detector based on W0.8Si0.2, and we characterized its basic detection performance for keV-photons at different temperatures. The detector has a critical temperature of 4.97 K, and it is able to be operated up to 4.8 K, just below the critical temperature. The detector starts to react to X-ray photons at relatively low bias currents, less than 1% of Ic at T = 1.8 K, and it shows a saturated count rate dependence on bias current at all temperatures, indicating that the optimum internal quantum efficiency can always be reached. Dark counts are negligible up to the highest investigated bias currents (99% of Ic and operating temperature (4.8 K. The latching effect affects the detector performance at all temperatures due to the fast recovery of the bias current; however, further modifications of the device geometry are expected to reduce the tendency for latching.

Synthesis of LiMn2O4 and LiCr0.2Mn1.8O4 powders by modified Pechini process

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Alexandre Urbano

2009-03-01

Full Text Available LiMn2O4 and LiCr0.2Mn1.8O4 powders were synthesized by Pechini process, modified in order to reduce the number of steps and to work at temperatures below or equal to 400oC. Both phases crystallize in the same spinel structure with lattice constants of 8.21 and 8.22 Å respectively. Although the annealing temperature was low, the cristallinity is good and no residual amounts of organic material were detected.

(2S,7S-10-Ethyl-1,8,10,12-tetraazatetracyclo[8.3.1.18,12.02,7]pentadecan-10-ium iodide

Directory of Open Access Journals (Sweden)

Augusto Rivera

2012-10-01

Full Text Available The title chiral quaternary ammonium salt, C13H25N4+·I−, was synthesized through the Menschutkin reaction between the cage aminal (2S,7S-1,8,10,12-tetraazatetracyclo[8.3.1.18,12.02,7]pentadecane and ethyl iodide. The quaternization occurred regioselectively on the nitrogen with major sp3 character. The crystal structure consists of anions and cations separated by normal distances. Ions are not linked through C—H...I hydrogen bonds.

Mechanism of a strong rise of Tc due to the calcium doping in Y1-xCaxBa2Cu2.8Zn0.2Oy

International Nuclear Information System (INIS)

Martynova, O.A.; Potapov, D.V.; Gasumyants, V.E.; Vladimirskaya, E.V.

2011-01-01

Highlights: → Calcium is observed to restore superconductivity in Y 1-x Ca x Ba 2 Cu 2.8 Zn 0.2 O y . → Parameters of the band spectrum and charge-carrier system are determined. → The calcium doping is shown to give a noticeable contribution to the DOS function. → The mechanism of calcium effect on T c in doped YBa 2 Cu 3 O y is discussed. - Abstract: The normal-state transport properties and the critical temperature, T c , for three series of Y 1-x Ca x Ba 2 Cu 2.8 Zn 0.2 O y (x = 0-0.2) samples with different oxygen content have been investigated and discussed in comparison with results for other calcium-doped YBa 2 Cu 3 O y . We have observed the calcium doping to restore the superconductivity in the YBa 2 Cu 3 O y system even in case of the preliminary T c suppression by the direct destruction of the CuO 2 planes due to a preliminary doping by zinc. The T c value rises strongly with increasing calcium content and this rise becomes faster for the oxygen-reduced series. Based on a narrow-band model, the parameters of the band spectrum structure and the charge-carrier system in the normal state were determined from the analysis of the thermopower temperature dependences in order to reveal the mechanism of the T c rise under the Ca influence. It is shown that the T c increase in Y 1-x Ca x Ba 2 Cu 2.8 Zn 0.2 O y is related to the direct Ca ions effect. The mechanism of the calcium influence on the T c value is discussed with respect to the Ca-induced conduction band modification. The calcium doping in Y 1-x Ca x Ba 2 Cu 2.8 Zn 0.2 O y is shown to give a noticeable contribution to the density-of-states function leading to a strong rise in its value at the Fermi level that results in a restoration of the superconducting properties.

(La, Pr)0.8Sr0.2FeO3-δ-Sm 0.2Ce0.8O2-δ composite cathode for proton-conducting solid oxide fuel cells

KAUST Repository

Chen, Yonghong; Gu, Qingwen; Tian, Dong; Ding, Yanzhi; Lu, Xiaoyong; Yu, Weili; Isimjan, Tayirjan T.; Lin, Bin

2014-01-01

thermal compatibility between electrodes and electrolyte. An anode-supported single cell of NiO-BZCY|BZCY|LPSF0.2-SDC was successfully fabricated and operated from 700 °C to 550 °C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. A

Magnetic characterization of Nd0.8Sr0.2(Mn1-x Co x )O3 perovskites

International Nuclear Information System (INIS)

Vidal, Karmele; Lezama, Luis; Arriortua, Maria I.; Rojo, Teofilo; Gutierrez, Jon; Barandiaran, Jose M.

2005-01-01

We present a magnetic study of the family of perovskites Nd 0.8 Sr 0.2 (Mn 1- x Co x )O 3 (x=0.1, 0.2 and 0.3). These compositions have been prepared by using both the sol-gel method and the freeze-drying technique. As a result, we have obtained polycrystalline powder-like samples. We have obtained pure compounds that have been indexed in the Pnma space group. The study of their magnetic properties shows a decrease of the measured low-temperature magnetic moment as the content of Co increases in the composition. However, a similar magnetic ordering temperature of about 130 K has been determined for all samples. All the studied compounds show insulating behaviour of the electrical resistivity

Structural, optical and vibrational studies of Na{sup +} doped Cd{sub 0.8}Zn{sub 0.2}S semiconductor compounds

Energy Technology Data Exchange (ETDEWEB)

Yellaiah, G., E-mail: johngolluri@yahoo.com; Hadasa, K.; Nagabhushanam, M., E-mail: mamidala_nb@yahoo.com

2013-12-25

Graphical abstract: FTIR spectra of Cd{sub 0.8}Zn{sub 0.2}S: N{sub x} (x = 0.2 mol%). Highlights: •The energy band gaps of Cd{sub 0.8}Zn{sub 02}S: Nasamples were estimated. •Density and porosity percentages were calculated. •From the FTIR study CdS and ZnS stretching bonds were detected. -- Abstract: Cd{sub 0.8}Zn{sub 0.2}S semiconductor powders doped with different amounts of sodium have been synthesized by controlled co-precipitation technique. X-ray diffraction (XRD), Scanning electron microscope (SEM), Optical absorption and Fourier transform infrared spectroscope (FTIR) studies have been done on all these samples. XRD studies have revealed that the samples are polycrystalline with an average crystallite size ranging from 29 to 55 nm and they crystallize in the hexagonal form with wurtzite structure. The optical measurements revealed that the samples possess direct band gap and the band gap increases with an increase in the dopant concentration. The vibrational modes of Cd–S and Zn–S were obtained from FTIR studies and found to be at 812–618 cm{sup −1} respectively. Experimental and theoretical (XRD) densities were calculated and analyzed. Density from XRD and porosity in percentage varied from 92% to 94% and 5% to 8% respectively. The elemental analysis of the compounds was done by energy dispersive spectroscopy (EDS) and found that the cadmium, zinc, sulphur and sodium elements were present in the compound as per the composition taken. From the theoretical estimations it is understood that the dopant (Na) occupies the interstitial of CdZnS.

La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) nanocomposite cathode for low temperature SOFCs.

Science.gov (United States)

Raza, Rizwan; Abbas, Ghazanfar; Liu, Qinghua; Patel, Imran; Zhu, Bin

2012-06-01

Nanocomposite based cathode materials compatible for low temperature solid oxide fuel cells (LTSOFCs) are being developed. In pursuit of compatible cathode, this research aims to synthesis and investigation nanocomposite La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) based system. The material was synthesized through wet chemical method and investigated for oxide-ceria composite based electrolyte LTSOFCs. Electrical property was studied by AC electrochemical impedance spectroscopy (EIS). The microstructure, thermal properties, and elemental analysis of the samples were characterized by TGA/DSC, XRD, SEM, respectively. The AC conductivity of cathode was obtained for 2.4 Scm(-1) at 550 degrees C in air. This cathode is compatible with ceria-based composite electrolytes and has improved the stability of the material in SOFC cathode environment.

Magnetisation and AC susceptibility studies of La1-xSrxFe0.8Cr0.2O3-δ (0.0

International Nuclear Information System (INIS)

Ferreira, L.P.; Cruz, M.M.; Ramos, T.; Sa, M.A.; Carvalho, M.D.; Godinho, M.

2007-01-01

Magnetisation and AC magnetic susceptibility measurements have been performed in the perovskite-type compounds La 1-x Sr x Fe 0.8 Cr 0.2 O 3-δ (x=0.2, 0.4, 0.6 and 0.8). All compounds show an overall antiferromagnetic behaviour mainly attributed to predominant Fe 3+ -O-Fe 3+ interactions. For 0.2 ord . The coexistence of AFM and FM interactions leads to reentrant magnetic behaviour for the x=0.4 compound and to spin-glass like behaviour for x=0.8. Between x=0.6 and 0.8, the similar magnetic moments found in the paramagnetic region indicate that the Fe/Cr valences do not change significantly, pointing towards an increased role for oxygen vacancy formation in the charge compensation mechanism

Effects of Zr4+ codoping on the Lu0.8Sc0.2BO3:Ce scintillation materials

International Nuclear Information System (INIS)

Wu, Yuntao; Ren, Guohao; Ding, Dongzhou; Shang, Shanshan; Sun, Dandan; Zhang, Guoqing; Wang, Jiayu; Pan, Shangke; Yang, Fan

2013-01-01

Both Zr-codoped Lu 0.8 Sc 0.2 BO 3 :Ce polycrystalline powders and single crystals were obtained by solid-state reaction and Czochralski method, respectively. The effects of Zr codoping on the optical absorption, Ce 3+ /Ce 4+ ratio, scintillation efficiency, decay time and point defect in Lu 0.8 Sc 0.2 BO 3 :Ce materials were examined systematically. Our results show that there is no positive contribution of Zr 4+ ion codoping to the scintillation efficiency. And the reasons for the deterioration of scintillation efficiency by codoping Zr 4+ were revealed. - Highlights: ► No positive contribution of the Zr 4+ ions on the scintillation efficiency was found. ► New optical absorption band was in the region from 200 to 225 nm. ► Continuously accelerated decay time indicated that Zr 4+ codoping induced new point defects. ► The induced hole trap located at 1.91 eV below the conduction band.

Band alignment of atomic layer deposited MgO/Zn0.8Al0.2O heterointerface determined by charge corrected X-ray photoelectron spectroscopy

Science.gov (United States)

Yan, Baojun; Liu, Shulin; Yang, Yuzhen; Heng, Yuekun

2016-05-01

Pure magnesium (MgO) and zinc oxide doped with aluminum oxide (Zn0.8Al0.2O) were prepared via atomic layer deposition. We have studied the structure and band gap of bulk Zn0.8Al0.2O material by X-ray diffractometer (XRD) and Tauc method, and the band offsets and alignment of atomic layer deposited MgO/Zn0.8Al0.2O heterointerface were investigated systematically using X-ray photoelectron spectroscopy (XPS) in this study. Different methodologies, such as neutralizing electron gun, the use of C 1s peak recalibration and zero charging method, were applied to recover the actual position of the core levels in insulator materials which were easily influenced by differential charging phenomena. Schematic band alignment diagram, valence band offset (ΔEV) and conduction band offset (ΔEC) for the interface of the MgO/Zn0.8Al0.2O heterostructure have been constructed. An accurate value of ΔEV = 0.72 ± 0.11 eV was obtained from various combinations of core levels of heterojunction with varied MgO thickness. Given the experimental band gaps of 7.83 eV for MgO and 5.29 eV for Zn0.8Al0.2O, a type-II heterojunction with a ΔEC of 3.26 ± 0.11 eV was found. Band offsets and alignment studies of these heterojunctions are important for gaining deep consideration to the design of various optoelectronic devices based on such heterointerface.

Study on magnetic properties of (Nd{sub 0.8}Ce{sub 0.2}){sub 2−x}Fe{sub 12}Co{sub 2}B (x = 0–0.6) alloys

Energy Technology Data Exchange (ETDEWEB)

Tan, G.S.; Xu, H., E-mail: huixu8888@shu.edu.cn; Yu, L.Y.; Tan, X.H.; Zhang, Q.; Gu, Y.; Hou, X.L.

2017-09-01

Highlights: • (Nd{sub 0.8}Ce{sub 0.2}){sub 2−x}Fe{sub 12}Co{sub 2}B alloys are prepared by melt-spinning method with simultaneously decreasing of Nd, Ce concentration. • The magnetic properties B{sub r}, (BH){sub max} and squareness are all improved with an appropriate reduction of Nd, Ce concentration. • Magnetic field heat treatment offers a significant improvement in B{sub r}, (BH){sub max} and squareness. - Abstract: In the present work, (Nd{sub 0.8}Ce{sub 0.2}){sub 2−x}Fe{sub 12}Co{sub 2}B (x = 0–0.6) permanent alloys are prepared by melt-spinning method. The hard magnetic properties of (Nd{sub 0.8}Ce{sub 0.2}){sub 2−x}Fe{sub 12}Co{sub 2}B (x = 0–0.6) alloys annealed at optimum temperatures have been investigated systematically. Depending on the Nd, Ce concentration, the maximum energy product ((BH){sub max}) and remanence (B{sub r}) increase gradually with x in the range of 0 ≤ x ≤ 0.4, whereas decrease gradually in the alloys with 0.4 < x ≤ 0.6. It is found that the optimum magnetic properties are obtained at x = 0.4: H{sub ci} = 4.9 kOe, B{sub r} = 10.1 kG, (BH){sub max} = 13.7 MGOe. Specifically, magnetic field heat treatment below the Curie temperature is applied for (Nd{sub 0.8}Ce{sub 0.2}){sub 1.6}Fe{sub 12}Co{sub 2}B (x = 0.4) annealed ribbons. The magnetic properties B{sub r}, (BH){sub max} and squareness are all enhanced after the magnetic field heat treatment. The (BH){sub max} shows a substantial increase from 13.7 MGOe to 16.0 MGOe after the heat treatment at 623 K with a magnetic field of 1 T, which gets 17% improvement compared with that of the sample without a magnetic field heat treatment. We demonstrate that the magnetic field heat treatment plays a certain role in the magnetization reversal behavior and can improve the microstructure of (Nd{sub 0.8}Ce{sub 0.2}){sub 1.6}Fe{sub 12}Co{sub 2}B alloy.

EXAFS and EPR study of La0.6Sr0.2Ca0.2MnO3 and La0.6Sr0.2Ba0.2MnO3

International Nuclear Information System (INIS)

Yang, D.-K.Dong-Seok; Ulyanov, A.N.; Phan, Manh-Huong; Kim, Ikgyun; Ahn, Byong-Keun; Rhee, Jang Roh; Kim, Jung Sun; Nguyen, Chau; Yu, Seong-Cho

2003-01-01

Extended X-ray absorption fine structure (EXAFS) analysis and electron-paramagnetic resonance (EPR) have been used to examine the local structure and the internal dynamics of La 0.6 Sr 0.2 Ca 0.2 MnO 3 and La 0.6 Sr 0.2 Ba 0.2 MnO 3 lanthanum manganites. The Mn-O bond distance (∼1.94 Angst for both samples) and the Debye-Waller factors (0.36x10 -2 and 0.41x10 -2 Angst 2 for La 0.6 Sr 0.2 Ca 0.2 MnO 3 and for La 0.6 Sr 0.2 Ba 0.2 MnO 3 , respectively) were obtained from the EXAFS analysis. The dependence of the EPR line width on dopant kind (Ca or Ba) showed a decrease of the spin-lattice interaction with an increase of the Curie temperature. For both compositions, the EPR line intensity followed the exponential law I(T)=I 0 exp(E a /k B T), deduced on the basis of the adiabatic polaron hopping model

Magnetic transitions in the system YBa2Cu/sub 2.8/Co/sub 0.2/O/sub 6+y/

International Nuclear Information System (INIS)

Miceli, P.F.; Tarascon, J.M.; Barboux, P.; Greene, L.H.; Bagley, B.G.; Hull, G.W.; Giroud, M.; Rhyne, J.J.; Neumann, D.A.; National Institute of Standards and Technology, Gaithersburg, Maryland 20899)

1989-01-01

We have studied the oxygen dependence of the two magnetic transitions (antiferromagnetic ordering of chains and planes) in YBa 2 Cu/sub 2.8/Co/sub 0.2/O/sub 6+y/ using neutron scattering. It is found that both transition temperatures increase with decreasing oxygen concentration. At y approx. 0.37 ( equivalent to y 0 ) the two transition temperatures are equal, so that chains and planes order at a single transition temperature for y less than or equal to y/sub 0/. For y=1 the compound is superconducting at 60 K. Therefore, this system qualitatively exhibits the magnetic and superconducting properties of pure YBa 2 Cu 3 O/sub 6+y/ while providing important insight on the oxygen dependence of chain site magnetic ordering. A discussion is presented which also includes results on Ni and Al substitutions

Comparação entre troponina I cardíaca e CK-MB massa em síndrome coronariana aguda sem supra de ST

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Elizabete Silva dos Santos

2011-03-01

Full Text Available FUNDAMENTO: Há incertezas do valor prognóstico comparativo entre troponina I cardíaca (cTnI e CK-MB em síndrome coronariana aguda (SCA. OBJETIVO: Comparar o valor prognóstico entre a cTnI e a CK-MB massa em pacientes com SCA sem supradesnível do segmento ST. MÉTODOS: Foram analisados 1.027 pacientes, de modo prospectivo, em um centro terciário de cardiologia. Combinações dos biomarcadores foram examinadas: cTnI normal, CK-MB massa normal (65,5%; cTnI normal, CK-MB massa elevada (3,9%; cTnI elevada, CK-MB massa normal (8,8%; cTnI elevada, CK-MB massa elevada (20,7%. Análise multivariada de variáveis clínicas, eletrocardiográficas e laboratoriais determinou o valor prognóstico independente dos biomarcadores para o evento de morte ou (reinfarto em 30 dias. RESULTADOS: Pacientes com pelo menos um biomarcador elevado foram mais idosos (p = 0,02 e do sexo masculino (p < 0,001. Uso prévio de aspirina (p = 0,001, betabloqueador (p = 0,003 ou estatina (p = 0,013 foi mais frequente naqueles sem elevação da cTnI. Pacientes com elevação de ambos os biomarcadores tinham mais depressão do segmento ST (p < 0,001 ou creatinina elevada (p < 0,001. Em análise multivariada com a inclusão da cTnI, a CK-MB massa não foi variável independente para o evento de morte ou (reinfarto em 30 dias (odds ratio [OR] 1,16; p = 0,71. Quando não se incluiu a cTnI, teve-se: idade (OR 1,07; p < 0,001; sexo masculino (OR 1,09; p = 0,77; diabete melito (OR 1,95; p = 0,02; acidente vascular cerebral prévio (OR 3,21; p = 0,008; creatinina elevada (OR 1,63; p = 0,002; elevação da CK-MB massa (OR 1,96; p = 0,03; estatística-C 0,77 (p < 0,001. CONCLUSÃO: Com dosagem da cTnI, a CK-MB massa pode ser dispensável para avaliação prognóstica. Na indisponibilidade da cTnI, a CK-MB massa é aceitável para decisão terapêutica.

Pembuatan La0,8Ca0,2MnO3 sebagai Katoda pada Solid Oxide Fuel Cell (SOFC dan Karakteristiknya

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Riska Ekawati

2007-06-01

Full Text Available The making of La0,8Ca0,2MnO3 cathode material of solid oxide fuel cell from lanthanum oxide (La2O3, calcium oxide (CaO, and manganese carbonate hydrate (MnCO3.H2O has been done using tape casting method. Time of firing the La0,8Ca0,2MnO3 varied. The values of t = 30 minutes, 60 minutes and 120 minutes. Microstructure of these materials was analyzed and characterized by means of their electric conductivity, XRD (x ray diffraction and SEM (scanning electron microscope. It is found that formulated micro structure is orthorhombic. The result of measurement shows that density is in linear (positive correlation with increasing of holding time of firing, porosity and coefficient of thermal expansion is negatively correlated with density and electric conductivity is in linear (positive correlation with increase density.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Anomalous low temperature resistivity in CeCr0.8V0.2Ge3

Science.gov (United States)

Singh, Durgesh; Patidar, Manju Mishra; Mishra, A. K.; Krishnan, M.; Ganesan, V.

2018-04-01

Resistivity (8T) and heat capacity (0T) of CeCr0.8V0.2Ge3 at low temperatures and high magnetic fields are reported. Resistivity curve shows a Kondo like behavior at an anomalously high temperature of 250K. A broad peak at 20K is observed in resistivity. A sharp change in resistivity around 7.3K is due to magnetic ordering mediated by coherence effects. Similar low temperature peak is also observed in heat capacity around 7.2K. A small magnetic field of the order of 1T shifts the peak towards lower temperatures confirming the antiferromagnetic ordering. A broad feature, which appears in resistivity at 20K, is absent in heat capacity. This feature shift towards higher temperatures with magnetic field, and may be due to the partial ferromagnetic ordering or due to geometrical frustration which opposes the magnetic ordering. The system shows a moderate heavy fermion behavior with Sommerfeld coefficient (γ) of 111mJ/mol-K2. Debye temperature of the compound is 250K. Shifting of TN in magnetic fields towards 0K indicates a possibility of quantum criticality in this system.

[Clinical Significance of ID4 Gene Mehtylation in Demethylation-Treated MDS Cell Line and 2 MDS Patients].

Science.gov (United States)

Kang, Hui-Yuan; Wang, Xin-Rong; Gao, Li; Wang, Wei; Li, Mian-Yang; Wang, Li-Li; Wang, Cheng-Bin; Yu, Li

2015-04-01

To evaluate significance of ID4 gene mehtylation in demethylating myelodysplastic syndrome(MDS) cell Line MUTZ1 and 2 patients with MDS. The methylation-specific PCR (MS-PCR) and reverse transcription-PCR (RT-PCR) were applied to identify the methylation status and gene expression of ID4 gene in MDS cell line MUTZ1, a patient with aplastic anemia(AA) and a donor with normal bone marrow (NBM). RT-PCR was applied to detect the ID4 gene expression status in MUTZ1 cell line treated with decitabine at 3 different concentrations. Then bisulfite sequencing PCR (BSP) was applied to detect ID4 gene methylation status in 2 MDS parients treated with decitabine. The MDS cell line MUTZ-1 displayed a complete methylation of ID4 gene promoter with little mRNA expression. Inversely, bone marrow of an AA patient and NBM showed complete unmethylation of this gene with intensity mRNA expression. With the increase of decitabine concentration, ID4 gene mRNA expression was more and more increased. After decitabine treatment, ID4 gene methylation-positive frequencies of both the 2 MDS patients were much more decreased than that of the first treatment. So, ID4 gene mRNA expression inhibited by promoter hypemethylation could be recovered by using demethylation medicine. ID4 as a new potential anti-oncogene suggests that its methylation may become a marker for selection and assessment of therapeutic schedules in patients with MDS.

Comparison in the electronic structure of YBa{sub 2}Fe{sub 3}O{sub 8} insulator with YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} superconductors

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y.; Guan, X.Y. [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Pan, M. [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Zhao, Y., E-mail: yzhao@home.swjtu.edu.cn [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)

2013-10-15

Highlights: • The electronic structure of YBa{sub 2}Fe{sub 3}O{sub 8}, YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} were investigated by XPS. • The core-level and valence-band structures of these systems are different. • The density of states at Fermi level is related to the superconductivity. -- Abstract: The electronic structure and chemical states of relevant elements of YBa{sub 2}Fe{sub 3}O{sub 8} are investigated using X-ray photoemission spectroscopy (XPS), compared with those of YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} superconductors. The typical differences and similarities in core-level and valence-band structures of these systems have been detected, strongly suggesting that the superconductivity have the finite density of states around Fermi level. Several features of O1s, Y3d, Ba3d, and Fe2p core lines in XPS spectra are also carefully compared and analyzed.

Experimental determination of the Onsager coefficients of transport for Ce0.8Pr0.2O2−δ

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Park, Woo-Seok; Kim, Hong-Seok

2010-01-01

versa for the flux of electrons (Je). It is common practice to assume that electrons and mobile ions migrate independently, despite the lack of experimental evidence in support of this. Here, all the Onsager coefficients, including the cross coefficients, have been measured for Ce0.8Pr0.2O2−δ within...... the aO2 range 10−21–1 at 800 °C, using local ionic and electronic probes in a four-probe configuration. The cross coefficients of transport were found to be negligible in comparison to the direct coefficients in the aO2 range 10−21–10−4, but of the same order of magnitude as the direct coefficients...

A monolithic 3.1-4.8 GHz MB-OFDM UWB transceiver in 0.18-μm CMOS

International Nuclear Information System (INIS)

Zheng Renliang; Jiang Xudong; Yao Wang; Yang Guang; Yin Jiangwei; Zheng Jianqin; Ren Junyan; Li Wei; Li Ning

2010-01-01

A monolithic RF transceiver for an MB-OFDM UWB system in 3.1-4.8 GHz is presented. The transceiver adopts direct-conversion architecture and integrates all building blocks including a gain controllable wideband LNA, a I/Q merged quadrature mixer, a fifth-order Gm-C bi-quad Chebyshev LPF/VGA, a fast-settling frequency synthesizer with a poly-phase filter, a linear broadband up-conversion quadrature modulator, an active D2S converter and a variable-gain power amplifier. The ESD protected transceiver is fabricated in Jazz Semiconductor's 0.18-μm RF CMOS with an area of 6.1 mm 2 and draws a total current of 221 mA from 1.8-V supply. The receiver achieves a maximum voltage gain of 68 dB with a control range of 42 dB in 6 dB/step, noise figures of 5.5-8.8 dB for three sub-bands, and an in-band/out-band IIP3 better than -4 dBm/+9 dBm. The transmitter achieves an output power ranging from -10.7 to -3 dBm with gain control, an output P 1dB better than -7.7 dBm, a sideband rejection about 32.4 dBc, and LO suppression of 31.1 dBc. The hopping time among sub-bands is less than 2.05 ns. (semiconductor integrated circuits)

The large Debye-Scherrer camera installed at SPring-8 BL02B2 for charge density studies

CERN Document Server

Nishibori, E; Kato, K; Sakata, M; Kubota, Y; Aoyagi, S; Kuroiwa, Y; Yamakata, M; Ikeda, N

2001-01-01

The design and performance of a large Debye-Scherrer Camera with imaging plate (IP) as a detector, which was very recently installed at SPring-8, BL02B2, is reported. By taking advantage of high beam quality of SPring-8, the camera enables one a rapid collection of a high counting statistics and high angular resolution powder pattern, which can lead to accurate structure analyses. The camera also provides easy access to structural changes at varied temperatures between 15-1000 K. The camera provides a rapid and accurate powder diffraction system utilizing third generation SR.

Effect of pressure on photo-induced expansion of As0.2Se0.8 layer

International Nuclear Information System (INIS)

Charnovych, S.; Kokenyesi, S.; Erdelyi, G.; Csik, A.

2011-01-01

Complete text of publication follows. Amorphous chalcogenide glasses are well known as materials where different kinds of structure-related transformations, like amorphysation-crystallization, volume and chemical stability changes take place under certain external influences (heat-, light-, and electric field). In spite of a rather long history of investigations and even some important applications in memory devices the mechanism of these effects is not completely clear, since besides the necessary condition of light interaction with glass and charge generation of the mass transport, shift or diffusion of atoms must occur. Unfortunately, we have only very little information about the light induced atomic transport processes in amorphous chalcogenides. Recent investigations on light-induced expansion, and holographic recording in chalcogenide glasses show that As 0.2 Se 0.8 composition reveals giant photo-expansion and photoplasticity effects. We selected this material for more detailed investigations of the direct relief formation process. In this work we investigate the influence of hydrostatic pressure on photo-stimulated surface relief formation in As 0.2 Se 0.8 thin films. 1 μm tick layers were evaporated from bulk glassy materials. Silica glass plates were used as substrate for films. The thickness of the layers were measured with profilometer type Ambios XP-I. The samples were illuminated with red laser beam (633 nm, output power P=7.5mW) through a copper grid, which resulted to an imprint picture on the surface of the film with interference fringes at the edges. In this way surface relief with different heights were formed after the given exposure according to the distribution of light intensity. The measurements were carried out at room temperature in a large-volume (1 cm 3 ) optical cell having sapphire windows. The hydrostatic pressure was generated by means of a 3-stage gas compressor. We used profilometer as well as scanning electron- and atomic force

Effect of microstructure on the high temperature mechanical properties of (CeO{sub 2}){sub 0.8}(GdO{sub 1.5}){sub 0.2} electrolytes

Energy Technology Data Exchange (ETDEWEB)

Sammes, N.M.; Zhang, Y. [Univ. of Waikato, Hamilton (New Zealand)

1996-12-31

CeO{sub 2}-based oxides have recently been shown to have great potential as electrolytes in medium temperature solid oxide fuel cell applications, primarily due to their high ionic conductivity. Steele et al., for example, have examined a cell of the type: O{sub 2}, La{sub 0.6}Sr{sub 0.4}Fe{sub 0.8}Co{sub 0.2}O{sub 3}{vert_bar}Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95}{vert_bar}Ni-ZrO{sub 2}, H{sub 2}/H{sub 2}O at 715{degrees}C. Gd{sub 2}O{sub 3} doped CeO{sub 2} has been reported as having one of the highest oxygen ion conductivities of the ceria-based materials. An ionic conductivity of 8.3 x 10{sup -2} s/cm has been reported for (CeO{sub 2}){sub 0.8}(GdO{sub 1.5}){sub 0.2} at 800{degrees}C, which is approximately four times that of Y{sub 2}O{sub 3}-doped ZrO{sub 2}, at the same temperature. Although the electrical properties of the material have been examined in detail, very little work has considered the microstructural/property relationships, particularly in relation to the mechanical properties. It is well know that CeO{sub 2}-based materials are difficult to density and attempts have been performed to examine this. Preliminary studies have also been undertaken to examine the effect of sintering on the mechanical properties of the material. In this paper we examine the effect of microstructure on the high temperature mechanical properties of (CeO{sub 2}){sub 0.8}(GdO{sub 1.5}){sub 0.2}.

Structure of superhard tungsten tetraboride: A missing link between MB2 and MB12 higher borides

Science.gov (United States)

Lech, Andrew T.; Turner, Christopher L.; Mohammadi, Reza; Tolbert, Sarah H.; Kaner, Richard B.

2015-01-01

Superhard metals are of interest as possible replacements with enhanced properties over the metal carbides commonly used in cutting, drilling, and wear-resistant tooling. Of the superhard metals, the highest boride of tungsten—often referred to as WB4 and sometimes as W1–xB3—is one of the most promising candidates. The structure of this boride, however, has never been fully resolved, despite the fact that it was discovered in 1961—a fact that severely limits our understanding of its structure–property relationships and has generated increasing controversy in the literature. Here, we present a new crystallographic model of this compound based on refinement against time-of-flight neutron diffraction data. Contrary to previous X-ray–only structural refinements, there is strong evidence for the presence of interstitial arrangements of boron atoms and polyhedral bonding. The formation of these polyhedra—slightly distorted boron cuboctahedra—appears to be dependent upon the defective nature of the tungsten-deficient metal sublattice. This previously unidentified structure type has an intermediary relationship between MB2 and MB12 type boride polymorphs. Manipulation of the fractionally occupied metal and boron sites may provide insight for the rational design of new superhard metals. PMID:25733870

Deformation Behavior of a Coarse-Grained Mg-8Al-1.5Ca-0.2Sr Magnesium Alloy at Elevated Temperatures

Science.gov (United States)

Lou, Yan; Liu, Xiao

2018-02-01

The compression tests were carried out on a coarse-grained Mg-8Al-1.5Ca-0.2Sr magnesium alloy samples at temperatures from 300 to 450 °C and strain rates from 0.001 to 10 s-1. The flow stress curves were analyzed using the double-differentiation method, and double minima were detected on the flow curves. The first set of minima is shown to identify the critical strain for twinning, while the second set indicates the critical strain for the initiation of dynamic recrystallization (DRX). Twin variant selection was numerically identified by comprehensive analysis of the Schmid factors for different deformation modes and the accommodation strains imposed on neighboring grains. It was found that twinning is initiated before DRX. Dynamic recrystallization volume increases with strain rate at a given deformation temperature. At high strain rate, various twin variants are activated to accommodate deformation, leading to the formation of twin intersections and high DRX volume. Fully dynamic recrystallized structure can be obtained at both high and low strain rates due to the high mobility of the grain and twin boundaries at the temperature of 400 °C.

Structural, magnetic and transport studies of Mn0.8Cr0.2CoGe alloy

Science.gov (United States)

Das, S. C.; Dutta, P.; Pramanick, S.; Chatterjee, S.

2018-04-01

Different physical and functional properties of Mn0.8Cr0.2CoGe alloy has been investigated through structural, magnetic and electrical transport measurements. Substitution of Cr for Mn results significant decrease in both structural and magnetic transition temperature and brings them well below the room temperature. A reasonable amount of conventional magnetocaloric effect (ΔS˜ - 2.22 J/kg-K for magnetic field (H) changing from 0 to 50 kOe) with large relative cooling power (251.7 J/kg for H changing from 0 to 50 kOe) has also been observed around the region of transition. On thermal cycling through the structural transition, noticeable training effect is found to be associated with the resistivity of the alloy.

Correlating thermoelectric properties with microstructure in Bi0.8Sb0.2 thin films

Science.gov (United States)

Siegal, M. P.; Lima-Sharma, A. L.; Sharma, P. A.; Rochford, C.

2017-04-01

The room temperature electronic transport properties of 100 nm-thick thermoelectric Bi0.8Sb0.2 films, sputter-deposited onto quartz substrates and post-annealed in an ex-situ furnace, systematically correlate with the overall microstructural quality, improving with increasing annealing temperature until close to the melting point for the alloy composition. The optimized films have high crystalline quality with ˜99% of the grains oriented with the trigonal axis perpendicular to the substrate surface. Film resistivities and Seebeck coefficients are accurately measured by preventing deleterious surface oxide formation via a SiN capping layer and using Nd-doped Al for contacts. The resulting values are similar to single crystals and significantly better than previous reports from films and polycrystalline bulk alloys.

Synthesis, thermal and electrical properties of Al-doped Bi{sub 4}V{sub 1.8}Cu{sub 0.2}O{sub 10.7}

Energy Technology Data Exchange (ETDEWEB)

Essalim, R.; Ammar, A.; Tanouti, B. [Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications (LASMIA), Equipe Matériaux à Faible Dimensionnalité(EMAFAD), Faculté des Sciences, Semlalia, Av. My Abdellah, B.P. 2390 Marrakech (Morocco); Mauvy, F., E-mail: fabrice.mauvy@cnrs.fr [Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) CNRS UPR 9048, Université de Bordeaux, 87, Av. Dr A. Schweitzer, 33608 Pessac (France)

2016-08-15

Partial substitution of copper with aluminum in Bi{sub 4}V{sub 1.8}Cu{sub 0.2}O{sub 10.7} has led to the Bi{sub 4}V{sub 1.8}Cu{sub 0.2−x}Al{sub x}O{sub 10.7+x/2} solid solution. X-ray diffraction and thermal analysis have shown that the compounds with x=0.05 and x=0.10 are tetragonal with γ′ form of Bi{sub 4}V{sub 2}O{sub 11}, while the compound with x=0.15 is of β polymorph. The effect of Al{sup 3+} doping on electrical conductivity has been studied using Electrochemical Impedance Spectroscopy. The electrical conductivity of doped samples along with the amount of Al{sup 3+} has been studied by electrochemical impedance spectroscopy in the temperature range 250–700 °C. The slope changes observed in the Arrhenius plots agree with the microstructural transitions occurring in these compounds. The highest ionic conductivity values are obtained for the sample with x=0.05. - Graphical abstract: Arrhenius plots of the electrical conductivity of the of Bi{sub 4}V{sub 1.8}Cu{sub 0.2−x}Al{sub x}O{sub 10.7+x/2} compounds. Display Omitted.

Size effect on the magnetic properties of antiferromagnetic La0.2Ca0.8MnO3 nanoparticles

Science.gov (United States)

Markovich, V.; Fita, I.; Wisniewski, A.; Mogilyansky, D.; Puzniak, R.; Titelman, L.; Martin, C.; Gorodetsky, G.

2010-03-01

Magnetic properties of electron-doped La0.2Ca0.8MnO3 manganite nanoparticles with average particle size ranging from 15 to 37 nm, prepared by the glycine-nitrate method, have been investigated in temperature range 5-300 K and in magnetic fields up to 90 kOe. A monotonous enhancement of weak ferromagnetism linked to the reduction in the particle size was observed for all nanoparticles. Magnetic hysteresis loops also indicate size-dependent exchange bias effect displayed by horizontal and vertical shifts in field-cooled processes. The magnetization data reveal two ferromagnetic components: first one appears at T˜200K and may be attributed to surface magnetization and second one appears as a result of spin canting of antiferromagnetic core or is developed at some interfaces inside nanoparticles. Time evolution of magnetization recorded in magnetic fields after the field cooling to low temperatures exhibits a very noisy behavior that may be caused by formation of collective state of nanoparticles with no clear tendency to reach equilibrium state. Magnetic properties of the nanoparticle samples are compared with those of the bulk La0.2Ca0.8MnO3 .

A monolithic 3.1-4.8 GHz MB-OFDM UWB transceiver in 0.18-{mu}m CMOS

Energy Technology Data Exchange (ETDEWEB)

Zheng Renliang; Jiang Xudong; Yao Wang; Yang Guang; Yin Jiangwei; Zheng Jianqin; Ren Junyan; Li Wei; Li Ning, E-mail: jyren@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

2010-06-15

A monolithic RF transceiver for an MB-OFDM UWB system in 3.1-4.8 GHz is presented. The transceiver adopts direct-conversion architecture and integrates all building blocks including a gain controllable wideband LNA, a I/Q merged quadrature mixer, a fifth-order Gm-C bi-quad Chebyshev LPF/VGA, a fast-settling frequency synthesizer with a poly-phase filter, a linear broadband up-conversion quadrature modulator, an active D2S converter and a variable-gain power amplifier. The ESD protected transceiver is fabricated in Jazz Semiconductor's 0.18-{mu}m RF CMOS with an area of 6.1 mm{sup 2} and draws a total current of 221 mA from 1.8-V supply. The receiver achieves a maximum voltage gain of 68 dB with a control range of 42 dB in 6 dB/step, noise figures of 5.5-8.8 dB for three sub-bands, and an in-band/out-band IIP3 better than -4 dBm/+9 dBm. The transmitter achieves an output power ranging from -10.7 to -3 dBm with gain control, an output P{sub 1dB} better than -7.7 dBm, a sideband rejection about 32.4 dBc, and LO suppression of 31.1 dBc. The hopping time among sub-bands is less than 2.05 ns. (semiconductor integrated circuits)

Characterization of particulate sol-gel synthesis of LiNi0.8Co0.2O2 via maleic acid assistance with different solvents

International Nuclear Information System (INIS)

Zhong, Y.D.; Zhao, X.B.; Cao, G.S.; Tu, J.P.; Zhu, T.J.

2006-01-01

Particulate sol-gel LiNi 0.8 Co 0.2 O 2 has been synthesized by a maleic-acid-assisted process using de-ionized water or ethanol as the solvent. A comparison of the effect on these two different solvents was made on the basis of thermal studies, Fourier transform infrared spectroscopy, X-ray diffraction analysis, chemical diffusion coefficients measurement, and electrochemical cyclability tests. An esterification reaction occurred on the xerogel prepared with ethanol as solvent, reducing Ni and Co from their nitrate salts. LiNi 0.8 Co 0.2 O 2 grew at the expense of Li 2 CO 3 , NiO, and CoO during calcination. Better results of capacity and cyclability were obtained in a DI-water-solvent sample associated with a larger interslab thickness between O-Li-O and lower Ni occupancy on the Li site. The activation energy for the calcinations of DI-water-solvent sample is one-half of that of the ethanol-solvent one, which could be the reason for its better properties. Chemical diffusion coefficients of Li + ion are of the same order 10 -10 cm 2 /s, is not affected by the solvents used and/or the temperature raise to 55 deg. C

Size dependent magnetic and magneto-optical properties of Ni{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Li, Oksana A., E-mail: log85@mail.ru [Department of Applied Physics, National Pingtung University, Pingtung 90003, Taiwan (China); Siberian Federal University, Krasnoyarsk 660041 (Russian Federation); Lin, Chun-Rong, E-mail: crlin@mail.nptu.edu.tw [Department of Applied Physics, National Pingtung University, Pingtung 90003, Taiwan (China); Chen, Hung-Yi; Hsu, Hua-Shu [Department of Applied Physics, National Pingtung University, Pingtung 90003, Taiwan (China); Shih, Kun-Yauh [Department of Applied Chemistry, National Pingtung University, Pingtung 90003, Taiwan (China); Edelman, Irina S. [L.V. Kirensky Institute of Physics, SB RAS, Krasnoyarsk 660036 (Russian Federation); Wu, Kai-Wun; Tseng, Yaw-Teng [Department of Applied Physics, National Pingtung University, Pingtung 90003, Taiwan (China); Ovchinnikov, Sergey G. [Siberian Federal University, Krasnoyarsk 660041 (Russian Federation); L.V. Kirensky Institute of Physics, SB RAS, Krasnoyarsk 660036 (Russian Federation); Lee, Jiann-Shing [Department of Applied Physics, National Pingtung University, Pingtung 90003, Taiwan (China)

2016-06-15

Ni{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4} spinel nanoparticles have been synthesized by combustion method. Average particles size varies from 15.5 to 50.0 nm depending on annealing temperature. Correlations between particles size and magnetic and magneto-optical properties are investigated. Magnetization dependences on temperature and external magnetic field correspond to the sum of paramagnetic and superparamagnetic response. Critical size of single-domain transition is found to be 15.9 nm. Magnetic circular dichroism (MCD) studies of nickel zinc spinel are presented here for the first time. The features in magnetic circular dichroism spectrum are assigned to the one-ion d–d transitions in Fe{sup 3+} and Ni{sup 2+} ions, as well to the intersublattice and intervalence charge transfer transitions. The MCD spectrum rearrangement was revealed with the change of the nanoparticles size. - Highlights: • Ni{sub 0.2}Zn{sub 0.8}Fe{sub 2}O{sub 4} nanoparticles were synthesized by combustion method. • Structure and magnetic properties are studied. • Magnetic circular dichroism (MCD) of nickel zinc spinel was measured for the first time. • The MCD spectrum rearrangement was revealed with the change of the nanoparticles size.

Oxygen and minority carrier lifetimes in N-and P-type AL0.2GA0.8AS grown by metal organics vapor phase epitaxy

International Nuclear Information System (INIS)

Zahraman, Khaled; Leroux, M.; Gibart, P.; Zaidi, M.A.; Bremond, G.; Guillot, G.

2000-01-01

author.The minority carrier lifetimes in Al x Ga 1-x As grown by Metal-Organics Vapor Phase Epitaxy (MOVPE) is generally lower than in GaAs. This is believed to be due to oxygen incorporation in the layers. We describe a study of radiative and non radiative minority carriers lifetimes in n-and p-type Al 0.2 Ga 0.8 As as a function of growth parameters, in correlation with oxygen concentration measurements and deep level transient spectroscopy (DLTS) studies. Long non radiative lifetimes and low oxygen contents are achieved using temperature growth. A main minority hole lifetime killer appears to be 0.4 eV deep O related electron trap detected by DLTS at concentrations three orders of magnitude lower than the atomic oxygen one. Record lifetimes in MOVPE grown n-and p-type Al 0.2 Ga 0.8 As are obtained. An Al 0.85 Ga 0.15 As/Al 0.2 Ga 0.8 As surface recombination velocity lower than 4.5x10 3 cm.s -1 is measured

Microscopic Structure of DX Centers in Cd0.8Zn0.2Te:Cl

International Nuclear Information System (INIS)

Shan, Y.Y.; Lynn, K.G.; Szeles, C.; Asoka-Kumar, P.; Thio, T.; Bennett, J.W.; Beling, C.B.; Fung, S.; Becla, P.

1997-01-01

Photoexcitation of chlorine DX centers induces a transition of the Cl atoms to the shallow-donor state and persistent photoconductivity at low temperature in Cd 0.8 Zn 0.2 Te:Cl. The relaxation of the substitutional Cl atoms to the DX state at 140K is coincident with a decrease of the positron line-shape parameter and an increase of annihilation with high-momentum core electrons. The results indicate positron trapping and annihilation at DX centers and at chlorine A centers. The data support the bond breaking model of the DX centers and the outward relaxation of the Cl and Cd(Zn) atoms along the [111] direction. The thermal barrier for the shallow-deep transition was found to be 0.44eV. copyright 1997 The American Physical Society

Aerosol deposition of Ba0.8Sr0.2TiO3 thin films

Directory of Open Access Journals (Sweden)

Branković Zorica

2009-01-01

Full Text Available In this work we optimized conditions for aerosol deposition of homogeneous, nanograined, smooth Ba0.8Sr0.2TiO3 thin films. Investigation involved optimization of deposition parameters, namely deposition time and temperature for different substrates. Solutions were prepared from titanium isopropoxide, strontium acetate and barium acetate. Films were deposited on Si (1 0 0 or Si covered by platinum (Pt (1 1 1 /Ti/SiO2/Si. Investigation showed that the best films were obtained at substrate temperature of 85ºC. After deposition films were slowly heated up to 650ºC, annealed for 30 min, and slowly cooled. Grain size of BST films deposited on Si substrate were in the range 40-70 nm, depending on deposition conditions, while the same films deposited on Pt substrates showed mean grain size in the range 35-50 nm. Films deposited under optimal conditions were very homogeneous, crackfree, and smooth with rms roughness lower than 4 nm for both substrates.

Structural and piezoelectric properties of aged 1-mol% Li2O-excess (Na0.51K0.47Li0.02)(Nb0.8Ta0.2)O3 ceramics

International Nuclear Information System (INIS)

Moon, Sang-Ho; Yun, Seok-Woo; Ham, Yong-Su; Lee, Young-Hie; Nam, Song-Min; Koh, Jung-Hyuk; Jeong, Soon-Jong; Kim, Min-Soo

2010-01-01

One (1)-mol% Li 2 O-excess (Na 0.51 K 0.47 Li 0.02 )(Nb 0.8 Ta 0.2 )O 3 lead-free piezoelectric ceramics were aged under different unipolar electric fields. Unipolar electric fields of 3, 5, and 7 kV/cm were applied to the specimens to accelerate the electric aging behavior. By employing a unipolar electric field for the piezoelectric actuators, we were able to remove undesirable heating problem from the relaxation current in the ferroelectric domain motions. To accelerate the aging test, we used an applied electric fields with a frequency of 910 Hz. To earn enough time for charging and discharging, we used an accurate time constant for the equivalent model for the piezoelectric actuators. X-ray diffraction analyses were carried out to determine the structural aging behavior of the poled piezoelectric specimens. As the piezoelectric specimens were exposed to high electric fields for aging tests, the actuators lost their tetragonality and took on a pseudo-cubic structure. The cycling dependent piezoelectric coefficient and electromechnical coupling coefficient followed a stretched exponential law as aging process.

Giant strain with low cycling degradation in Ta-doped [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}]TiO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaoming; Tan, Xiaoli, E-mail: xtan@iastate.edu [Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2016-07-21

Non-textured polycrystalline [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}](Ti{sub 1−x}Ta{sub x})O{sub 3} ceramics are fabricated and their microstructures and electrical properties are characterized. Transmission electron microscopy reveals the coexistence of the rhombohedral R3c and tetragonal P4bm phases in the form of nanometer-sized domains in [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}]TiO{sub 3} with low Ta concentration. When the composition is x = 0.015, the electrostrain is found to be highly asymmetric under bipolar fields of ±50 kV/cm. A very large value of 0.62% is observed in this ceramic, corresponding to a large-signal piezoelectric coefficient d{sub 33}* of 1240 pm/V (1120 pm/V under unipolar loading). These values are greater than most previously reported lead-free polycrystalline ceramics and can even be compared with some lead-free piezoelectric single crystals. Additionally, this ceramic displays low cycling degradation; its electrostrain remains above 0.55% even after undergoing 10 000 cycles of ±50 kV/cm bipolar fields at 2 Hz. Therefore, Ta-doped [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}]TiO{sub 3} ceramics show great potential for large displacement devices.

The nonlinear optical properties of a magneto-exciton in a strained Ga0.2In0.8As/GaAs quantum dot

International Nuclear Information System (INIS)

Kumar, N. R. Senthil; Peter, A. John; Yoo Chang Kyoo

2013-01-01

The magnetic field-dependent heavy hole excitonic states in a strained Ga 0.2 In 0.8 As/GaAs quantum dot are investigated by taking into account the anisotropy, non-parabolicity of the conduction band, and the geometrical confinement. The strained quantum dot is considered as a parabolic dot of InAs embedded in a GaAs barrier material. The dependence of the effective excitonic g-factor as a function of dot radius and the magnetic field strength is numerically measured. The interband optical transition energy as a function of geometrical confinement is computed in the presence of a magnetic field. The magnetic field-dependent oscillator strength of interband transition under the geometrical confinement is studied. The exchange enhancements as a function of dot radius are observed for various magnetic field strengths in a strained Ga 0.2 In 0.8 As/GaAs quantum dot. Heavy hole excitonic absorption spectra, the changes in refractive index, and the third-order susceptibility of third-order harmonic generation are investigated in the Ga 0.2 In 0.8 As/GaAs quantum dot. The result shows that the effect of magnetic field strength is more strongly dependent on the nonlinear optical property in a low-dimensional semiconductor system. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

A high performance BaZr0.1Ce0.7Y0.2O3-δ-based solid oxide fuel cell with a cobalt-free Ba0.5Sr0.5FeO3-δ–Ce0.8Sm0.2O2-δ composite cathode

NARCIS (Netherlands)

Sun, Wenping; Shi, Zhen; Fang, S.; Yan, Litao; Zhu, Zhiwen; Liu, Wei

2010-01-01

A cobalt-free Ba0.5Sr0.5FeO3-δ–Ce0.8Sm0.2O2-δ (BSF–SDC) composite is employed as a cathode for an anode-supported proton-conducting solid oxide fuel cells (H-SOFCs) using BaZr0.1Ce0.7Y0.2O3-δ (BZCY) as the electrolyte. The chemical compatibility between BSF and SDC is evaluated. The XRD results show

Band alignment of atomic layer deposited MgO/Zn{sub 0.8}Al{sub 0.2}O heterointerface determined by charge corrected X-ray photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Yan, Baojun, E-mail: yanbj@ihep.ac.cn [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics of Chinese Academy of Sciences, Beijing P. O. Box 100049 (China); Liu, Shulin [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics of Chinese Academy of Sciences, Beijing P. O. Box 100049 (China); Yang, Yuzhen [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics of Chinese Academy of Sciences, Beijing P. O. Box 100049 (China); Department of Physics, Nanjing University, Nanjing P. O. Box 210093 (China); Heng, Yuekun [State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics of Chinese Academy of Sciences, Beijing P. O. Box 100049 (China)

2016-05-15

Highlights: • Band alignment of MgO/Zn{sub 0.8}Al{sub 0.2}O heterojunction were investigated systematically using charge corrected X-ray photoelectron spectroscopy. • Differential charging phenomenon is observed in determination VBOs of insulator/semiconductor heterojunction. • Valence and conduction band offsets have been determined to be 0.72 ± 0.11 eV and 3.26 ± 0.11 eV, respectively, with a type-II band line-up. - Abstract: Pure magnesium (MgO) and zinc oxide doped with aluminum oxide (Zn{sub 0.8}Al{sub 0.2}O) were prepared via atomic layer deposition. We have studied the structure and band gap of bulk Zn{sub 0.8}Al{sub 0.2}O material by X-ray diffractometer (XRD) and Tauc method, and the band offsets and alignment of atomic layer deposited MgO/Zn{sub 0.8}Al{sub 0.2}O heterointerface were investigated systematically using X-ray photoelectron spectroscopy (XPS) in this study. Different methodologies, such as neutralizing electron gun, the use of C 1s peak recalibration and zero charging method, were applied to recover the actual position of the core levels in insulator materials which were easily influenced by differential charging phenomena. Schematic band alignment diagram, valence band offset (ΔE{sub V}) and conduction band offset (ΔE{sub C}) for the interface of the MgO/Zn{sub 0.8}Al{sub 0.2}O heterostructure have been constructed. An accurate value of ΔE{sub V} = 0.72 ± 0.11 eV was obtained from various combinations of core levels of heterojunction with varied MgO thickness. Given the experimental band gaps of 7.83 eV for MgO and 5.29 eV for Zn{sub 0.8}Al{sub 0.2}O, a type-II heterojunction with a ΔE{sub C} of 3.26 ± 0.11 eV was found. Band offsets and alignment studies of these heterojunctions are important for gaining deep consideration to the design of various optoelectronic devices based on such heterointerface.

Observation of spin reorientation in layered manganites La1.2Sr1.8(Mn1-yRuy)2O7 (0.0=0.2) by Lorentz transmission electron microscopy

International Nuclear Information System (INIS)

Yu, X.Z.; Uchida, M.; Onose, Y.; He, J.P.; Kaneko, Y.; Asaka, T.; Kimoto, K.; Matsui, Y.; Arima, T.; Tokura, Y.

2006-01-01

The effect of Ru substitution for Mn in bilayered oxides La 1.2 Sr 1.8 (Mn 1-y Ru y ) 2 O 7 (0= for the y=0 crystal to the c-axis for y=0.2, and it rotates away from the c-axis for the y=0.05 and y=0.07 crystals with decreasing temperature. Furthermore, maze-shaped magnetic domain structures were observed in the (001) thin crystals with 0.05=< y=<0.2. Changes in domain size and structure indicate that the uniaxial magnetic anisotropy becomes stronger as Ru content y increases

Rietveld refinement and dielectric studies of Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} ceramic

Energy Technology Data Exchange (ETDEWEB)

Kaswan, Kavita, E-mail: kaswan.kavita@gmail.com; Agarwal, Ashish; Sanghi, Sujata; Rangi, Manisha; Jangra, Sandhaya; Singh, Ompal [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India)

2016-05-23

Polycrystalline Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} ceramic has been synthesized via conventional solid state reaction technique. The Rietveld refinement of x-ray powder diffraction revealed that the sample has a rhombohedral crystal structure (space group R3c). With increase in temperature, the values of dielectric constant (ϵ′) and dielectric loss (tan δ) are found to be increase at different frequencies which may be the result of increase in the number of charge carriers and their mobilities due to the thermal activation. Further the ac conductivity data is analyzed by using Jonscher’s universal power law. The values of frequency exponent ‘s’ lies in the range 0.2 ≤ s ≤ 0.7 and decreases with increase in temperature which can be explained on the basis of CBH (Correlated Barrier Height) model.

Single-crystal LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} as high performance cathode materials for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Wang, Lei [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing Key Laboratory of Environment Science and Engineering, Beijing 100081 (China); Wu, Borong, E-mail: wubr@bit.edu.cn [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing Key Laboratory of Environment Science and Engineering, Beijing 100081 (China); Beijing Higher Institution Engineering Research Center of Power Battery and Chemical Energy Materials, Beijing 100081 (China); Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081 (China); Mu, Daobin, E-mail: mudb@bit.edu.cn [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing Key Laboratory of Environment Science and Engineering, Beijing 100081 (China); Beijing Higher Institution Engineering Research Center of Power Battery and Chemical Energy Materials, Beijing 100081 (China); Liu, Xiaojiang [Institute of Electric Engineering, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, Yiyuan [Key Laboratory of Small Fuctional Organic Molecule, Ministry of Education, Jiangxi Normal University, Nanchang 330022 (China); Xu, Hongliang; Liu, Qi; Gai, Liang [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing Key Laboratory of Environment Science and Engineering, Beijing 100081 (China); Wu, Feng [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing Key Laboratory of Environment Science and Engineering, Beijing 100081 (China); Beijing Higher Institution Engineering Research Center of Power Battery and Chemical Energy Materials, Beijing 100081 (China); Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081 (China)

2016-07-25

Single-crystal nickel-high materials (ST-LNCMO) LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} have been synthesized using a versatile hydrothermal method. The as-prepared samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and selected area electron diffraction (SAED). The results show that the sample annealed at an optimized temperature of 850 °C reveals uniform fine well-crystallized single-particles with diameters of ~800 nm. Electrochemical data demonstrate that the cell using this nickel-high material as the cathode exhibits excellent performance. The sample displays a high capacity of 183.7 mA h·g{sup −1} at 36 mA·g{sup −1} (0.2 C) and excellent cycling stability at different rates. It yields an initial discharge capacity of 153.6 mA h·g{sup −1} at a rate of 10C-rate and a voltage of 2.8 V – 4.3 V. The sample also has an outstanding rate capacity at a high cut-off voltage (4.6 V). This superior performance is attributed to the merits of the single-crystal structure, which may be beneficial to the transportation of the Li{sup +} ion along the grain. - Highlights: • A single-crystal LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} is prepared by a hydrothermal method. • A high discharge capacity of 183.7 mA h·g{sup −1} at 0.2 C and good cycling stability. • It yields an initial discharge capacity of 153.6 mA h·g{sup −1} at 10 C-rate under 2.8 V–4.3 V. • Superior electrochemical performance may be obtained attributed to the single-crystal structure.

In situ growth and characterization of La{sub 0.8}Sr{sub 0.2}CoO{sub 3} perovskite mixed conductor films

Energy Technology Data Exchange (ETDEWEB)

Brosha, E.L.; Chung, B.W.; Garzon, F.H.; Raistrick, I.D.; Houlton, R.J.; Hawley, M.E. [Los Alamos National Lab., NM (United States)

1995-05-01

The authors have grown thin films of La{sub 0.8}Sr{sub 0.2}CoO{sub 3} on SrTiO{sub 3} [100], MgO [100], yttrium-stabilized zirconia YSZ [100], and CeO{sub 2} [100]/Al{sub 2}O{sub 3} substrates by using a 90{degree} off-axis RF magnetron sputtering deposition. X-ray diffraction analysis reveals that, depending on substrate, the deposited films grew either epitaxially or highly textured. Scanning tunneling microscopy reveals that the thin films grow with a smooth surface and with different growth mechanisms according to substrate. For La{sub 0.8}Sr{sub 0.2}CoO{sub 3} thin films grown on MgO [100], the low values of the channeling minimum yield from Rutherford backscattering spectroscopy indicated excellent epitaxy with the substrate. Thin films of perovskite materials are among the major focal research areas for optical, sensor, electronic, and superconducting applications.

Preparation and Oxygen Permeability of BaCo0.7Fe0.2Nb0.1O3-δ Membrane Modified by Ce0.8Y0.2O2-δ Porous Layer on the Air Side

Directory of Open Access Journals (Sweden)

Yuan Qiang

2013-01-01

Full Text Available BaCo0.7Fe0.2Nb0.1O3−δ (BCFN dense ceramic membrane with submicron-Ce0.8Y0.2O2−δ (YDC porous layer was investigated by the partial oxidation of coke oven gas (COG in hydrogen production. XRD analysis showed this composite had good stability and no chemical reaction at high temperature. SEM and TEM characterization further showed BCFN membrane was uniformly modified by YDC porous layer (about 5~6 μm thickness formed by the accumulation of relative nanoparticles. At the respective COG flux and air flux of 108 mL/min and 173 mL/min, the oxygen permeation flux of BCFN modified by submicron-YDC porous layer reached 16.62 mL·min−1·cm−2, which was about 23.5% higher than that of pure BCFN membrane. Therefore, submicron-YDC porous layer obviously improved the oxygen permeation flux of BCFN membrane and its stability at 875°C.

A Rapid Culture Technique Produces Functional Dendritic-Like Cells from Human Acute Myeloid Leukemia Cell Lines

Directory of Open Access Journals (Sweden)

Jian Ning

2011-01-01

Full Text Available Most anti-cancer immunotherapeutic strategies involving dendritic cells (DC as vaccines rely upon the adoptive transfer of DC loaded with exogenous tumour-peptides. This study utilized human acute myeloid leukemia (AML cells as progenitors from which functional dendritic-like antigen presenting cells (DLC were generated, that constitutively express tumour antigens for recognition by CD8+ T cells. DLC were generated from AML cell lines KG-1 and MUTZ-3 using rapid culture techniques and appropriate cytokines. DLC were evaluated for their cell-surface phenotype, antigen uptake and ability to stimulate allogeneic responder cell proliferation, and production of IFN-γ; compared with DC derived from normal human PBMC donors. KG-1 and MUTZ-3 DLC increased expression of CD80, CD83, CD86, and HLA-DR, and MUTZ-3 DLC downregulated CD14 and expressed CD1a. Importantly, both KG-1 and MUTZ-3-derived DLC promoted proliferation of allogeneic responder cells more efficiently than unmodified cells; neither cells incorporated FITC-labeled dextran, but both stimulated IFN-γ production from responding allogeneic CD8+ T cells. Control DC produced from PBMC using the FastDC culture also expressed high levels of critical cell surface ligands and demonstrated good APC function. This paper indicates that functional DLC can be cultured from the AML cell lines KG-1 and MUTZ-3, and FastDC culture generates functional KG-1 DLC.

The MB2 gene family of Plasmodium species has a unique combination of S1 and GTP-binding domains

Directory of Open Access Journals (Sweden)

Ogunjumo Oluwasanmi

2004-06-01

Full Text Available Abstract Background Identification and characterization of novel Plasmodium gene families is necessary for developing new anti-malarial therapeutics. The products of the Plasmodium falciparum gene, MB2, were shown previously to have a stage-specific pattern of subcellular localization and proteolytic processing. Results Genes homologous to MB2 were identified in five additional parasite species, P. knowlesi, P. gallinaceum, P. berghei, P. yoelii, and P. chabaudi. Sequence comparisons among the MB2 gene products reveal amino acid conservation of structural features, including putative S1 and GTP-binding domains, and putative signal peptides and nuclear localization signals. Conclusions The combination of domains is unique to this gene family and indicates that MB2 genes comprise a novel family and therefore may be a good target for drug development.

The MB2 gene family of Plasmodium species has a unique combination of S1 and GTP-binding domains

Science.gov (United States)

Romero, Lisa C; Nguyen, Thanh V; Deville, Benoit; Ogunjumo, Oluwasanmi; James, Anthony A

2004-01-01

Background Identification and characterization of novel Plasmodium gene families is necessary for developing new anti-malarial therapeutics. The products of the Plasmodium falciparum gene, MB2, were shown previously to have a stage-specific pattern of subcellular localization and proteolytic processing. Results Genes homologous to MB2 were identified in five additional parasite species, P. knowlesi, P. gallinaceum, P. berghei, P. yoelii, and P. chabaudi. Sequence comparisons among the MB2 gene products reveal amino acid conservation of structural features, including putative S1 and GTP-binding domains, and putative signal peptides and nuclear localization signals. Conclusions The combination of domains is unique to this gene family and indicates that MB2 genes comprise a novel family and therefore may be a good target for drug development. PMID:15222903

Síntese e estudo microestrutural de perovsquitas tipo La0,8Ca0,2MO3 (M: Co e Mn para aplicação em catálise automotiva Synthesis and microstructural study of La0.8Ca0.2MO3 (M: Mn and Co perovskites for automotive catalysis

Directory of Open Access Journals (Sweden)

J. P. Ribeiro

2011-09-01

Full Text Available Materiais com estrutura perovsquita são potenciais catalisadores para prevenir a emissão de componentes indesejáveis ao meio ambiente. Diferentes métodos têm sido propostos para a síntese desses materiais, visando produzir materiais homogêneos com tamanho nanométrico de partículas. Os compostos La0,8Ca0,2MnO3 e La0,8Ca0,2CoO3 foram preparados pelo método dos precursores poliméricos visando sua utilização como catalisadores automotivos. Este método de síntese foi utilizado porque permite a obtenção de pós homogêneos e fases cristalinas a temperaturas mais baixas que os outros métodos tradicionais de síntese. Os materiais foram calcinados a 700 e 900 ºC por 4 h e caracterizados pelas técnicas de análise térmica, difração de raios X e microscopia eletrônica de varredura. As perovsquitas obtidas são nanométricas, monofásicas e com propriedades adequadas para utilização em catálise automotiva.Materials with perovskite structure are potential catalysts for preventing greenhouse gas emissions to the environment. Several methods have been proposed for the synthesis of these materials in order to produce homogeneous powders with nanometric particle size. In the present work, the La0.8Ca0.2MnO3 and La0.8Ca0.2CoO3 systems were prepared by the polymeric precursor method for application in automotive catalysis. This method was chosen because it allows obtaining homogeneous powders and crystalline phases at lower temperatures. The powders were calcined at 700 and 900 ºC for 4 h and characterized by thermal analysis, X-ray diffraction and scanning electron microscopy techniques. The perovskites are nanometric, single phased and present suitable properties for use in automotive catalysis.

High-Throughput Screening Across Quaternary Alloy Composition Space: Oxidation of (AlxFeyNi1-x-y)∼0.8Cr∼0.2.

Science.gov (United States)

Payne, Matthew A; Miller, James B; Gellman, Andrew J

2016-09-12

Composition spread alloy films (CSAFs) are commonly used as libraries for high-throughput screening of composition-property relationships in multicomponent materials science. Because lateral gradients afford two degrees of freedom, an n-component CSAF can, in principle, contain any composition range falling on a continuous two-dimensional surface through an (n - 1)-dimensional composition space. However, depending on the complexity of the CSAF gradients, characterizing and graphically representing this composition range may not be straightforward when n ≥ 4. The standard approach for combinatorial studies performed using quaternary or higher-order CSAFs has been to use fixed stoichiometric ratios of one or more components to force the composition range to fall on some well-defined plane in the composition space. In this work, we explore the synthesis of quaternary Al-Fe-Ni-Cr CSAFs with a rotatable shadow mask CSAF deposition tool, in which none of the component ratios are fixed. On the basis of the unique gradient geometry produced by the tool, we show that the continuous quaternary composition range of the CSAF can be rigorously represented using a set of two-dimensional "pseudoternary" composition diagrams. We then perform a case study of (AlxFeyNi1-x-y)∼0.8Cr∼0.2 oxidation in dry air at 427 °C to demonstrate how such CSAFs can be used to screen an alloy property across a continuous two-dimensional subspace of a quaternary composition space. We identify a continuous boundary through the (AlxFeyNi1-x-y)∼0.8Cr∼0.2 subspace at which the oxygen uptake into the CSAF between 1 and 16 h oxidation time increases abruptly with decreasing Al content. The results are compared to a previous study of the oxidation of AlxFeyNi1-x-y CSAFs in dry air at 427 °C.

Effect of Al-5Ti-0.62C-0.2Ce Master Alloy on the Microstructure and Tensile Properties of Commercial Pure Al and Hypoeutectic Al-8Si Alloy

Directory of Open Access Journals (Sweden)

Wanwu Ding

2017-06-01

Full Text Available Al-5Ti-0.62C-0.2Ce master alloy was synthesized by a method of thermal explosion reaction in pure molten aluminum and used to modify commercial pure Al and hypoeutectic Al-8Si alloy. The microstructure and tensile properties of commercial pure Al and hypoeutectic Al-8Si alloy with different additions of Al-5Ti-0.62C-0.2Ce master alloy were investigated. The results show that the Al-5Ti-0.62C-0.2Ce alloy was composed of α-Al, granular TiC, lump-like TiAl3 and block-like Ti2Al20Ce. Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 5 min can significantly refine macro grains of commercial pure Al into tiny equiaxed grains. The Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 30 min still has a good refinement effect. The tensile strength and elongation of commercial pure Al modified by the Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 5 min increased by roughly 19.26% and 61.83%, respectively. Al-5Ti-0.62C-0.2Ce master alloy (1.5 wt %, 10 min can significantly refine both α-Al grains and eutectic Si of hypoeutectic Al-8Si alloy. The dendritic α-Al grains were significantly refined to tiny equiaxed grains. The morphology of the eutectic Si crystals was significantly refined from coarse needle-shape or lath-shape to short rod-like or grain-like eutectic Si. The tensile strength and elongation of hypoeutectic Al-8Si alloy modified by the Al-5Ti-0.62C-0.2Ce master alloy (1.5 wt %, 10 min increased by roughly 20.53% and 50%, respectively. The change in mechanical properties corresponds to evolution of the microstructure.

Effect of Niobium doping on structural, thermal, sintering and electrical properties of Bi4V1.8Cu0.2O10.7

International Nuclear Information System (INIS)

Alga, M.; Ammar, A.; Tanouti, B.; Outzourhit, A.; Mauvy, F.; Decourt, R.

2005-01-01

Doping Bi 4 V 1.8 Cu 0.2 O 10.7 with niobium has led to the formation of the Bi 4 V 1.8 Cu 0.2-x Nb x O 10.7+3x/2 solid solution. X-ray diffraction and thermal analysis have shown that only the compound with x=0.05 presents a tetragonal symmetry with a γ ' polymorph while the other compositions are of β polymorph. The influence of sintering temperature on the microstructure of the samples was investigated by the scanning electron microscopy (SEM). The ceramics sintered at temperatures higher than 820 o C present micro-craks. The evolution of the electrical conductivity with temperature and the degree of substitution has been investigated by impedance spectroscopy. Among all compositions studied the sample with x=0.05 presents the highest value of the conductivity

Composite Ag-La0.8Sr0.2MnO3-σ Cathode for Solid Oxide Fuel Cells

Directory of Open Access Journals (Sweden)

Mosiałek M.

2013-12-01

Full Text Available Na powierzchni elektrolitu stałego wytwarzano kompozytowe katody dla stałotlenkowych ogniw paliwowych zbudowane z metalicznego srebra rozproszonego w osnowie z La0.8Sr0,3MnO3-σ Osnowę o kontrolowanej porowatości otrzymywano przez prażenie mieszaniny proszku La0.8Sr0.2MnO3-σ z kulkami z tworzywa organicznego. Porowatą osnowę nasycano roztworem AgNCb i ponownie wyprażano. Tak otrzymane katody wykazywały wyższą przewodność elektryczną i niższą oporność akty- wacyjną w reakcji redukcji tlenu w porównaniu z katodami z czystej ceramiki.

Properties and performance of BaxSr1-xCo0.8Fe0.2O3-d materials for oxygen transport membranes

NARCIS (Netherlands)

Vente, Jaap F.; McIntosh, S.; McIntosh, Steven; Haije, Wim G.; Bouwmeester, Henricus J.M.

2006-01-01

The present paper discusses the oxygen transport properties, oxygen stoichiometry, phase stability, and chemical and mechanical stability of the perovskites $${\\text{Ba}}_{{0.5}} {\\text{Sr}}_{{0.5}} {\\text{Co}}_{{0.8}} {\\text{Fe}}_{{0.2}} {\\text{O}}_{{3 - \\delta }} $$ (BSCF) and

Voltage-controlled ferroelastic switching in Pb(Zr.sub.0.2./sub.Ti.sub.0.8./sub.)O.sub.3./sub. thin films

Czech Academy of Sciences Publication Activity Database

Khan, A.I.; Martí, Xavier; Serrao, C.; Ramesh, R.; Salahuddin, S.

2015-01-01

Roč. 15, č. 4 (2015), s. 2229-2234 ISSN 1530-6984 Institutional support: RVO:68378271 Keywords : nanodomains * ferroelastic switching * ferroelectricity * Pb(Zr 0.2 Ti 0.8 )O 3 * thin film Subject RIV: BE - Theoretical Physics Impact factor: 13.779, year: 2015

Large magnetoresistance in Heusler-alloy-based epitaxial magnetic junctions with semiconducting Cu(In{sub 0.8}Ga{sub 0.2})Se{sub 2} spacer

Energy Technology Data Exchange (ETDEWEB)

Kasai, S. [Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako 351-0198 (Japan); Takahashi, Y. K.; Ohkubo, T. [Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Cheng, P.-H.; Ikhtiar,; Mitani, S.; Hono, K. [Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577 (Japan); Kondou, K. [Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako 351-0198 (Japan); Otani, Y. [Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako 351-0198 (Japan); Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8581 (Japan)

2016-07-18

We investigated the structure and magneto-transport properties of magnetic junctions using a Co{sub 2}Fe(Ga{sub 0.5}Ge{sub 0.5}) Heusler alloy as ferromagnetic electrodes and a Cu(In{sub 0.8}Ga{sub 0.2})Se{sub 2} (CIGS) semiconductor as spacers. Owing to the semiconducting nature of the CIGS spacer, large magnetoresistance (MR) ratios of 40% at room temperature and 100% at 8 K were obtained for low resistance-area product (RA) values between 0.3 and 3 Ω μm{sup 2}. Transmission electron microscopy observations confirmed the fully epitaxial growth of the chalcopyrite CIGS layer, and the temperature dependence of RA indicated that the large MR was due to spin dependent tunneling.

The fast neutron SEU cross section of a 4 Mb SRAM memory

International Nuclear Information System (INIS)

Pereira Junior, Evaldo C.F.; Goncalez, Odair L.; Cruz, Marco Aurelio da; Prado, Adriane Cristina Mendes; Federico, Claudio Antonio; Gaspar, Felipe de Barros

2013-01-01

The results of a static test of single event upset (SEU) produced by fast neutrons on an ISSI 4Mb SRAM memory are reported in this work. To perform the tests, it was built a platform based on a motherboard which is controlled by microprocessor, whose function is to perform the writing, reading and control of the memories under irradiation. The irradiation was performed with a set of 8 241 Am-Be neutrons source in a quasi-isotropic incidence. The SEU cross was calculated from the accumulated bit flip count. (author)

Proteomic analysis of trichloroethylene-induced alterations in expression, distribution, and interactions of SET/TAF-Iα and two SET/TAF-Iα-binding proteins, eEF1A1 and eEF1A2, in hepatic L-02 cells

Energy Technology Data Exchange (ETDEWEB)

Hong, Wen-Xu; Yang, Liang; Chen, Moutong; Yang, Xifei; Ren, Xiaohu; Fang, Shisong; Ye, Jinbo; Huang, Haiyan; Peng, Chaoqiong; Zhou, Li; Huang, Xinfeng; Yang, Fan; Wu, Desheng; Zhuang, Zhixiong; Liu, Jianjun, E-mail: bio-research@hotmail.com

2012-09-01

Emerging evidence indicates that trichloroethylene (TCE) exposure causes severe hepatotoxicity. However, the mechanisms of TCE hepatotoxicity remain unclear. Recently, we reported that TCE exposure up-regulated the expression of the oncoprotein SET/TAF-Iα and SET knockdown attenuated TCE-induced cytotoxicity in hepatic L-02 cells. To decipher the function of SET/TAF-Iα and its contributions to TCE-induced hepatotoxicity, we employed a proteomic analysis of SET/TAF-Iα with tandem affinity purification to identify SET/TAF-Iα-binding proteins. We identified 42 novel Gene Ontology co-annotated SET/TAF-Iα-binding proteins. The identifications of two of these proteins (eEF1A1, elongation factor 1-alpha 1; eEF1A2, elongation factor 1-alpha 2) were confirmed by Western blot analysis and co-immunoprecipitation (Co-IP). Furthermore, we analyzed the effects of TCE on the expression, distribution and interactions of eEF1A1, eEF1A2 and SET in L-02 cells. Western blot analysis reveals a significant up-regulation of eEF1A1, eEF1A2 and two isoforms of SET, and immunocytochemical analysis reveals that eEF1A1 and SET is redistributed by TCE. SET is redistributed from the nucleus to the cytoplasm, while eFE1A1 is translocated from the cytoplasm to the nucleus. Moreover, we find by Co-IP that TCE exposure significantly increases the interaction of SET with eEF1A2. Our data not only provide insights into the physiological functions of SET/TAF-Iα and complement the SET interaction networks, but also demonstrate that TCE exposure induces alterations in the expression, distribution and interactions of SET and its binding partners. These alterations may constitute the mechanisms of TCE cytotoxicity. -- Highlights: ► Identify 62 SET/TAF-Iα-associated proteins in human L-02 cells ► Trichloroethylene (TCE) alters the interaction of SET with eEF1A1 and eEF1A2. ► TCE induces the translocation and up-regulation of SET. ► TCE induces the translocation and up-regulation of eEF1A.

Proteomic analysis of trichloroethylene-induced alterations in expression, distribution, and interactions of SET/TAF-Iα and two SET/TAF-Iα-binding proteins, eEF1A1 and eEF1A2, in hepatic L-02 cells

International Nuclear Information System (INIS)

Hong, Wen-Xu; Yang, Liang; Chen, Moutong; Yang, Xifei; Ren, Xiaohu; Fang, Shisong; Ye, Jinbo; Huang, Haiyan; Peng, Chaoqiong; Zhou, Li; Huang, Xinfeng; Yang, Fan; Wu, Desheng; Zhuang, Zhixiong; Liu, Jianjun

2012-01-01

Emerging evidence indicates that trichloroethylene (TCE) exposure causes severe hepatotoxicity. However, the mechanisms of TCE hepatotoxicity remain unclear. Recently, we reported that TCE exposure up-regulated the expression of the oncoprotein SET/TAF-Iα and SET knockdown attenuated TCE-induced cytotoxicity in hepatic L-02 cells. To decipher the function of SET/TAF-Iα and its contributions to TCE-induced hepatotoxicity, we employed a proteomic analysis of SET/TAF-Iα with tandem affinity purification to identify SET/TAF-Iα-binding proteins. We identified 42 novel Gene Ontology co-annotated SET/TAF-Iα-binding proteins. The identifications of two of these proteins (eEF1A1, elongation factor 1-alpha 1; eEF1A2, elongation factor 1-alpha 2) were confirmed by Western blot analysis and co-immunoprecipitation (Co-IP). Furthermore, we analyzed the effects of TCE on the expression, distribution and interactions of eEF1A1, eEF1A2 and SET in L-02 cells. Western blot analysis reveals a significant up-regulation of eEF1A1, eEF1A2 and two isoforms of SET, and immunocytochemical analysis reveals that eEF1A1 and SET is redistributed by TCE. SET is redistributed from the nucleus to the cytoplasm, while eFE1A1 is translocated from the cytoplasm to the nucleus. Moreover, we find by Co-IP that TCE exposure significantly increases the interaction of SET with eEF1A2. Our data not only provide insights into the physiological functions of SET/TAF-Iα and complement the SET interaction networks, but also demonstrate that TCE exposure induces alterations in the expression, distribution and interactions of SET and its binding partners. These alterations may constitute the mechanisms of TCE cytotoxicity. -- Highlights: ► Identify 62 SET/TAF-Iα-associated proteins in human L-02 cells ► Trichloroethylene (TCE) alters the interaction of SET with eEF1A1 and eEF1A2. ► TCE induces the translocation and up-regulation of SET. ► TCE induces the translocation and up-regulation of eEF1A.

Evolution of E-centers during the annealing of Sb-doped Si0.8Ge0.2

DEFF Research Database (Denmark)

Kilpeläinen, S.; Tuomisto, F.; Slotte, J.

2011-01-01

Evolution of the chemical surroundings of vacancy complexes in Sb-doped ([Sb] = 2 × 1018 and 2 × 1019 cm−3) Si0.8Ge0.2 was studied with positron annihilation spectroscopy in Doppler broadening mode. The study was performed by annealing the samples both isochronally and isothermally. Defect...... evolution was observed at the temperature range 450–650 K. Both treatments were shown to induce changes in the chemical surroundings of the E-centers via introduction of Ge near the defects. Moreover, Sb was found to hinder these changes by stabilizing the E-centers and thus preventing them from finding Ge....... The stable state reached after the anneals was found to differ from that measured from an as-grown sample. This difference was deemed to be the result of Ge gathering in small clusters during the annealing thus breaking the initially random Ge distribution....

Unmasking of a hemizygous WFS1 gene mutation by a chromosome 4p deletion of 8.3 Mb in a patient with Wolf-Hirschhorn syndrome.

Science.gov (United States)

Flipsen-ten Berg, Klara; van Hasselt, Peter M; Eleveld, Marc J; van der Wijst, Suzanne E; Hol, Frans A; de Vroede, Monique A M; Beemer, Frits A; Hochstenbach, P F Ron; Poot, Martin

2007-11-01

The Wolf-Hirschhorn syndrome (WHS (MIM 194190)), which is characterized by growth delay, mental retardation, epilepsy, facial dysmorphisms, and midline fusion defects, shows extensive phenotypic variability. Several of the proposed mutational and epigenetic mechanisms in this and other chromosomal deletion syndromes fail to explain the observed phenotypic variability. To explain the complex phenotype of a patient with WHS and features reminiscent of Wolfram syndrome (WFS (MIM 222300)), we performed extensive clinical evaluation and classical and molecular cytogenetic (GTG banding, FISH and array-CGH) and WFS1 gene mutation analyses. We detected an 8.3 Mb terminal deletion and an adjacent 2.6 Mb inverted duplication in the short arm of chromosome 4, which encompasses a gene associated with WFS (WFS1). In addition, a nonsense mutation in exon 8 of the WFS1 gene was found on the structurally normal chromosome 4. The combination of the 4p deletion with the WFS1 point mutation explains the complex phenotype presented by our patient. This case further illustrates that unmasking of hemizygous recessive mutations by chromosomal deletions represents an additional explanation for the phenotypic variability observed in chromosomal deletion disorders.

Investigation of luminescence mechanism in La{sub 0.2}Y{sub 1.8}O{sub 3} scintillator

Energy Technology Data Exchange (ETDEWEB)

Sahi, Sunil [Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 (United States); Wang, Zhiqiang [Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7 (Canada); Luo, Junming [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Groza, Michael [Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208-3051 (United States); Li, Jiang [Key Laboratory of Transparent Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Junying [Department of Physics, Beihang University, Beijing 100191 (China); Chen, Wei, E-mail: weichen@uta.edu [Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 (United States); Pan, Yubai [Key Laboratory of Transparent Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Burger, Arnold [Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208-3051 (United States); Sham, Tsun-Kong [Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7 (Canada)

2016-05-15

La{sub 0.2}Y{sub 1.8}O{sub 3} is a new and promising scintillator which is based on the host material without doping. Here the time gated X-ray excited optical luminescence is measured by using the excitation energy below, above and at the La L{sub 3}-edge. A relatively slow and broad emission with peak at 415 nm has been observed as the dominant emission. Also, a weak emission at 360 nm is observed at the fast window, associated with the recombination of trapped excitons in Y{sub 2}O{sub 3} host. The observations show that the broad emission at 415 nm is most likely due to the recombination of trapped excitons associated with the La{sup 3+} doping into Y{sub 2}O{sub 3} sites.

Electric-field-control of magnetic anisotropy of Co0.6Fe0.2B0.2/oxide stacks using reduced voltage

Science.gov (United States)

Kita, Koji; Abraham, David W.; Gajek, Martin J.; Worledge, D. C.

2012-08-01

We have demonstrated purely electrical manipulation of the magnetic anisotropy of a Co0.6Fe0.2B0.2 film by applying only 8 V across the CoFeB/oxide stack. A clear transition from in-plane to perpendicular anisotropy was observed. The quantitative relationship between interface anisotropy energy and the applied electric-field was determined from the linear voltage dependence of the saturation field. By comparing the dielectric stacks of MgO/Al2O3 and MgO/HfO2/Al2O3, enhanced voltage control was also demonstrated, due to the higher dielectric constant of the HfO2. These results suggest the feasibility of purely electrical control of magnetization with small voltage bias for spintronics applications.

The effects of prior calcium channel blocker therapy on creatine kinase-MB levels after percutaneous coronary interventions

Directory of Open Access Journals (Sweden)

Oyku Gulmez

2008-12-01

Full Text Available Oyku Gulmez, Ilyas Atar, Bülent Ozin, Mehmet Emin Korkmaz, Aslı Atar, Alp Aydinalp, Aylin Yildirir, Haldun MuderrisogluBaskent University Faculty of Medicine, Department of Cardiology, Ankara, TurkeyBackground: Use of intracoronary calcium channel blockers (CCBs during percutaneous coronary intervention (PCI has been shown to have favorable effects on coronary blood flow. We aimed to investigate the effects of CCBs administrated perorally on creatine kinase-MB (CK-MB levels in patients undergoing elective PCI.Methods: A total of 570 patients who underwent PCI were evaluated for CK-MB elevation. Patients who were on CCB therapy when admitted to the hospital constituted the CCB group. No CCBs were given to the rest of the patients during the periprocedural period and these patients served as the control group. Blood samples for CK-MB were obtained before and at 6 h, 24 h, and 36 h after the procedure.Results: 217 patients were in the CCB group (mean age 60.2 ± 9.3 years, 162 males, and 353 were in the control group (mean age 60.0 ± 10.1 years, 262 males. CK-MB levels increased above the normal values in 41 patients (18.9% of the CCBs group and in 97 patients (27.5% of the control group (p = 0.02. Median CK-MB levels were significantly higher in the control group for all studied hours (for all p < 0.05.Conclusions: Prior oral CCB therapy may have favorable effects in preventing myocyte necrosis after elective PCI.Keywords: calcium channel blockers, myonecrosis, percutaneous coronary interventions

Synthesis of Nano-Structured La0.6Sr0.4Co0.2Fe0.8O3 Perovskite by Co-Precipitation Method

Directory of Open Access Journals (Sweden)

Ebrahim Mostafavi

2015-06-01

Full Text Available Nano-structured lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF, was successfully synthesized via co-precipitation method using metal nitrates as starting materials. Effects of precipitating agent and calcination temperature on the phase composition and morphology of synthesized powders were systematically studied using X-ray diffraction (XRD and field emission scanning electron microscopy (FESEM, respectively. XRD analysis revealed that a single phase La0.6Sr0.4Co0.2Fe0.8O3 perovskite was obtained in the processed sample using ammonium carbonate as precipitating agent with a NH4+/NO3-molar ratio of 2 after calcination at 1000C for 1 h. The phase composition of products was also affected by changing pH values. Moreover, using sodium hydroxide as a precipitant resulted in a mixture of La0.6Sr0.4Co0.2Fe0.8O3 and cobalt ferrite (CoFe2O4 phases. Careless washing of the precursors can also led to the formation of mixed phase after calcination of final powders. Mean crystallite size of the obtained powders was not noticeably affected by varying calcination temperature from 900 to 1050C and remained almost the same at 10 nm, however increasing calcination temperature to 1100C resulted in sharp structural coarsening. FESEM studies demonstrate that relatively uniform particles with mean particle size of 90 nm were obtained in the sample processed with a NH4+/NO3- molar ratio of 2 after calcination at 1000C for 1 h.

The LiyNi0.2Mn0.2Co0.6O2 electrode materials: A structural and magnetic study

International Nuclear Information System (INIS)

Labrini, Mohamed; Saadoune, Ismael; Almaggoussi, Abdelmajid; Elhaskouri, Jamal; Amoros, Pedro

2012-01-01

Graphical abstract: EPR signal of the Li 0.6 Co 0.6 Ni 0.2 Mn 0.2 O 2 composition showing that Mn 4+ ions are the solely paramagnetic ions in the structure. Highlights: ► LiCo 0.6 Ni 0.2 Mn 0.2 O 2 was prepared by the combustion method with sucrose as a fuel. ► Chemical delithiaition was performed by using NO 2 BF 4 oxidizing agent. ► The rhombohedral symmetry was preserved upon lithium removal. ► Lithium extraction leads to Ni 2+ oxidation to Ni 4+ followed by Co 3+ oxidation. ► The EPR narrow signal of Li 0.6 Co 0.6 Ni 0.2 Mn 0.2 O 2 is due to the only active Mn 4+ ions. -- Abstract: Layered LiNi 0.2 Mn 0.2 Co 0.6 O 2 phase, belonging to a solid solution between LiNi 1/2 Mn 1/2 O 2 and LiCoO 2 most commercialized cathodes, was prepared via the combustion method at 900 °C for a short time (1 h). Structural and magnetic properties of this material during chemical extraction were investigated. The powders adopted the α-NaFeO 2 structure with almost none of the well-known Li/Ni cation disorder. The analysis of the magnetic properties in the paramagnetic domain agrees with the combination of Ni 2+ (S = 1), Co 3+ (S = 0) and Mn 4+ (S = 3/2) spin-only values. X-ray analysis of the chemically delithiated Li y Ni 0.2 Mn 0.2 Co 0.6 O 2 reveals no structural transition. The process of lithium extraction from and insertion into LiNi 0.2 Mn 0.2 Co 0.6 O 2 was discussed on the basis of ex situ EPR experiments and magnetic susceptibility. Oxidation of Ni 2+ (S = 1) to Ni 3+ (S = 1/2) and to Ni 4+ (S = 0) was observed upon lithium removal.

In-plain electric properties of [CaMnO3/REMO3] (RE=Bi, La M=Fe, Fe0.8Mn0.2) superlattices grown by pulsed laser deposition method

NARCIS (Netherlands)

Iwata, N.; Watabe, Y.; Oikawa, T.; Takase, K.; Huijben, Mark; Inaba, T.; Oshima, K.; Rijnders, Augustinus J.H.M.; Yamamoto, H.

2014-01-01

The [CaMnO3 (CMO)/REMO3] (RE = Bi, La M = Fe, Fe0.8Mn0.2) superlattices show semiconducting behavior with transition temperatures (TEg) of 71, 127, and 151 K in the [CMO/BiFe0.8Mn0.2O3], [CMO/BiFeO3], and [CMO/LaFeO3] superlattices. The formation of a magnetic polaron is expected in the CMO layer of

A-Site Deficient (Pr0.6Sr0.4)(1-s)Fe0.8Co0.2O3-delta Perovskites as Solid Oxide Fuel Cell Cathodes

DEFF Research Database (Denmark)

Kammer Hansen, Kent

2009-01-01

Five A-site deficient (Pr0.6Sr0.4)1−sFe0.8Co0.2O3− perovskites (s=0.01, 0.05, 0.10, 0.15, and 0.20) were synthesized using the glycine-nitrate process. The perovskites were characterized with powder X-ray diffraction (XRD), dilatometry, four-point dc conductivity measurements, and electrochemical...... resistance more than 3 times lower than the weakly A-site deficient (Pr0.6Sr0.4)0.99Fe0.8Co0.2O3− perovskite. ©2009 The Electrochemical Society...

Pressure effect on crystal structure and superconductivity of La0.8Th0.2FeAsO

International Nuclear Information System (INIS)

Kumar, Ravhi S.; Antonio, Daniel; Cornelius, Andrew L.; Zhao, Yusheng; Kanagaraj, M.; Arumugam, S.; Sinogeikin, Stanislav; Prakash, J.; Thakur, Gohil S.; Ganguli, A.K.; Hartmann, Thomas

2011-01-01

We have studied the effect of pressure on the superconducting transition temperature (T c ) of thorium doped La 1-x Th x FeAsO (x = 0.2) superconductor under hydrostatic pressures up to 1.6 GPa by resistivity and magnetization experiments. Application of pressure increases the T c to 31 K with a positive pressure coefficient of ∝1 K/GPa. Low temperature X-ray diffraction studies performed at 7.8 K at high pressures show no pressure induced structural changes and the tetragonal P4/nmm structure is found to persist up to 31 GPa. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Synthesis and characterization of La0.8Sr0.2Ni(1−xCrxO3 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 system by the combustion method

Directory of Open Access Journals (Sweden)

Jairo Alberto Gómez-Cuaspud

2017-11-01

Full Text Available This research focuses on the synthesis and characterization of six ceramic perovskite oxides based on La0.8Sr0.2Ni(1−xCrxO3 system, with different levels of chromium modification (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, for use as anode material in solid oxide fuel cells (SOFC. The oxides were obtained in two reaction stages, starting from corresponding nitrate salts and citric acid until formation of a solid metal complex consistent with citrate species. The solid metalorganic foams were calcined at 1000 °C for 120 min under oxygen flow conditions and were characterized by infrared and ultraviolet spectroscopy (FTIR-UV, validating the proposed methodology in terms of purity and chemical composition. The characterization by X-ray diffraction (XRD, scanning electron microscopy (SEM and X-ray energy dispersive spectroscopy (EDX confirms the obtention of a homogeneous perovskite structure in all analyzed phases. The evaluation of crystallite size by means of the Debye–Scherrer equation establishes a nanometric prevalence around 3.2–4.4 nm along main diffraction signals. The electrical characterization of materials by solid-state impedance spectroscopy allowed identifying a particular behavior depending on the microstructure of solids for potential applications in SOFC devices. Resumen: Esta investigación se centra en la síntesis y caracterización de seis óxidos de perovskita cerámicos basados en el sistema La0.8Sr0.2Ni(1-xCrxO3, con diferentes niveles de modificación de cromo (x = 0.0, 0.2, 0.4, 0.6, 0.8 y 1.0, para uso como material de ánodo en pilas de combustible de óxido sólido (SOFC. Los óxidos se obtuvieron en dos etapas de reacción, partiendo de las correspondientes sales de nitrato y ácido cítrico hasta la formación de un complejo metálico sólido consistente con especies de citrato. Las espumas sólidas metal-orgánicas se calcinaron a 1000° C

Analysis of DNA restriction fragments greater than 5.7 Mb in size from the centromeric region of human chromosomes.

Science.gov (United States)

Arn, P H; Li, X; Smith, C; Hsu, M; Schwartz, D C; Jabs, E W

1991-01-01

Pulsed electrophoresis was used to study the organization of the human centromeric region. Genomic DNA was digested with rare-cutting enzymes. DNA fragments from 0.2 to greater than 5.7 Mb were separated by electrophoresis and hybridized with alphoid and simple DNA repeats. Rare-cutting enzymes (Mlu I, Nar I, Not I, Nru I, Sal I, Sfi I, Sst II) demonstrated fewer restriction sites at centromeric regions than elsewhere in the genome. The enzyme Not I had the fewest restriction sites at centromeric regions. As much as 70% of these sequences from the centromeric region are present in Not I DNA fragments greater than 5.7 and estimated to be as large as 10 Mb in size. Other repetitive sequences such as short interspersed repeated segments (SINEs), long interspersed repeated segments (LINEs), ribosomal DNA, and mini-satellite DNA that are not enriched at the centromeric region, are not enriched in Not I fragments of greater than 5.7 Mb in size.

CO Sensing Properties of Nanostructured La0.8Sr0.2CoO3 Sensors Synthesized by EDTA-Glycol Method

Directory of Open Access Journals (Sweden)

G. N. Chaudhari

2008-11-01

Full Text Available We report a simple method for the preparation of pure LaCoO3 and La1-xSrxCoO3 (x = 0.1, 0.2 and 0.25 nanostructures by the EDTA-Glycol method. The final powders obtained by this method have been investigated by X-ray diffraction (XRD and scanning electron microscopy (SEM measurements. The gas sensitivity of pure and Sr doped LaCoO3 samples were investigated for CO, NH3, H2 and LPG. La0.8Sr0.2CoO3 powders (sample GIII calcined at 6500C, exhibited a good sensor response towards CO gas at 2500C. On impregnation of 1 wt.% Pd over sample GIII, the operation temperature reduced to 2000C with a significant rise in sensitivity. The response time also decreases from about 3.5 min for sample GIII to less than 2.5 min for the Pd loaded element. The electronic interaction between Pd and metal oxide semiconductor is proposed to account for the sensitization effect.

Dendritic cell migration assay: a potential prediction model for identification of contact allergens.

Science.gov (United States)

Gibbs, Susan; Spiekstra, Sander; Corsini, Emanuela; McLeod, Julie; Reinders, Judith

2013-04-01

This manuscript describes methodology and a prediction model for the MUTZ-LC migration assay. The assay represents the physiological change in Langerhans cell (LC) behavior after exposure to a sensitizing chemical, resulting in LC migration from the epidermis to the dermis. MUTZ-LC are derived from the commercially available MUTZ-3 cell line. Upon exposure to a sensitizer MUTZ-LC migrate preferentially towards CXCL12 whereas upon exposure to a non-sensitizer MUTZ-LC migrate towards CCL5. A CXCL12/CCL5 ratio >1.10 in 2/3 independent experiments is indicative of a sensitizer, whereas a CXCL12/CCL5 ratio ≤1.10 is indicative of a non-sensitizer. At non cytotoxic chemical concentrations 9 sensitizers (2,4-dinitrochlorobenzene, paraphenylendiamine, cinnamaldehyde, isoeugenol, nickel-sulfate, tetramethylthiuram disulfide, eugenol, cinnamic-alcohol, ammonium-hexachloroplatinate) were distinguished from 4 non sensitizers (sodium lauryl sulfate, salicylic acid, phenol, octanoic acid). Critical points in assay performance are (i) MUTZ-3 passage number after thawing (p6-p40); (ii) cell viability (>80%); (iii) standard curve to optimize correlation of fluorescence with cell number; and (iv) optimization of the concentration of rhCXCL12 and rhCCL5 in transwell. The protocol has been tested in three European laboratories and results suggest that it may provide working conditions for performing the DC migration assay which is aimed at distinguishing sensitizers from non sensitizers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Engineering Mixed Ionic Electronic Conduction in La 0.8 Sr 0.2 MnO 3+ δ Nanostructures through Fast Grain Boundary Oxygen Diffusivity

KAUST Repository

Saranya, Aruppukottai M.; Pla, Dolors; Morata, Alex; Cavallaro, Andrea; Canales-Vá zquez, Jesú s; Kilner, John A.; Burriel, Mó nica; Tarancó n, Albert

2015-01-01

to implement in nanostructures. Here, an artificial mixed ionic electronic conducting oxide is fabricated by grain boundary (GB) engineering thin films of La0.8Sr0.2MnO3+δ. This electronic conductor is converted into a good mixed ionic electronic conductor

Ambipolar gate effect and low temperature magnetoresistance of ultrathin La0.8Ca0.2MnO3 films.

Science.gov (United States)

Eblen-Zayas, M; Bhattacharya, A; Staley, N E; Kobrinskii, A L; Goldman, A M

2005-01-28

Ultrathin La(0.8)Ca(0.2)MnO(3) films have been measured in a field-effect geometry. The gate electric field produces a significant ambipolar decrease in resistance at low temperatures. This is attributed to the development of a pseudogap in the density of states and the coupling of localized charge to strain. Within a mixed phase scenario, the gate effect and magnetoresistance are interpreted in the framework of a "general susceptibility," which describes how phase boundaries move through a hierarchical pinning landscape.

NCBI nr-aa BLAST: CBRC-DMEL-02-0080 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-02-0080 ref|NP_622419.1| Ribose/xylose/arabinose/galactoside ABC-type transport systems...inose/galactoside ABC-type transport systems, permease components [Thermoanaerobacter tengcongensis MB4] NP_622419.1 0.92 33% ...

Composite Fe - BaCe0.2Zr0.6Y0.2O2.9 Anodes for Proton Conductor Fuel Cells

DEFF Research Database (Denmark)

Lapina, Alberto; Chatzichristodoulou, Christodoulos; Holtappels, Peter

2014-01-01

Symmetrical cells with Fe - BaCe0.2Zr0.6Y0.2O2.9 composite electrodes are produced by screen printing and infiltration, using BaCe0.2Zr0.6Y0.2O2.9 as electrolyte. The electrochemical performance of the composite electrode is studied by impedance spectroscopy at 250–500◦C in dry and wet hydrogen/n...

Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature

CSIR Research Space (South Africa)

Raju, Kumar

2016-04-01

Full Text Available microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e., LiNi(sub0.2)Mn(sub1.8)O(sub4), herein abbreviated as LMNO) for lithium-ion batteries from Mn(sub3)O(sub4) which is prepared from electrolytic manganese...

Bias polarization study of steam electrolysis by composite oxygen electrode Ba0.5Sr0.5Co0.8Fe0.2O3-δ/BaCe0.4Zr0.4Y0.2O3-δ

Science.gov (United States)

Yang, Tao; Shaula, Aliaksandr; Pukazhselvan, D.; Ramasamy, Devaraj; Deng, Jiguang; da Silva, E. L.; Duarte, Ricardo; Saraiva, Jorge A.

2017-12-01

The polarization behavior of Ba0.5Sr0.5Co0.8Fe0.2O3-δ-BaCe0.4Zr0.4Y0.2O3-δ (BSCF-BCZY) electrode under steam electrolysis conditions was studied in detail. The composite oxygen electrode supported by BCZY electrolyzer has been assessed as a function of temperature (T), water vapor partial pressures (pH2O), and bias polarization voltage for electrodes of comparable microstructure. The Electrochemical impedance spectra show two depressed arcs in general without bias polarization. And the electrode resistance became smaller with the increase of the bias polarization under the same water vapor partial pressures. The total resistance of the electrode was shown to be significantly affected by temperature, with the same level of pH2O and bias polarization voltage. This result highlights BSCF-BCZY as an effective oxygen electrode under moderate polarization and pH2O conditions.

Proteomic analysis of trichloroethylene-induced alterations in expression, distribution, and interactions of SET/TAF-Iα and two SET/TAF-Iα-binding proteins, eEF1A1 and eEF1A2, in hepatic L-02 cells.

Science.gov (United States)

Hong, Wen-Xu; Yang, Liang; Chen, Moutong; Yang, Xifei; Ren, Xiaohu; Fang, Shisong; Ye, Jinbo; Huang, Haiyan; Peng, Chaoqiong; Zhou, Li; Huang, Xinfeng; Yang, Fan; Wu, Desheng; Zhuang, Zhixiong; Liu, Jianjun

2012-09-01

Emerging evidence indicates that trichloroethylene (TCE) exposure causes severe hepatotoxicity. However, the mechanisms of TCE hepatotoxicity remain unclear. Recently, we reported that TCE exposure up-regulated the expression of the oncoprotein SET/TAF-Iα and SET knockdown attenuated TCE-induced cytotoxicity in hepatic L-02 cells. To decipher the function of SET/TAF-Iα and its contributions to TCE-induced hepatotoxicity, we employed a proteomic analysis of SET/TAF-Iα with tandem affinity purification to identify SET/TAF-Iα-binding proteins. We identified 42 novel Gene Ontology co-annotated SET/TAF-Iα-binding proteins. The identifications of two of these proteins (eEF1A1, elongation factor 1-alpha 1; eEF1A2, elongation factor 1-alpha 2) were confirmed by Western blot analysis and co-immunoprecipitation (Co-IP). Furthermore, we analyzed the effects of TCE on the expression, distribution and interactions of eEF1A1, eEF1A2 and SET in L-02 cells. Western blot analysis reveals a significant up-regulation of eEF1A1, eEF1A2 and two isoforms of SET, and immunocytochemical analysis reveals that eEF1A1 and SET is redistributed by TCE. SET is redistributed from the nucleus to the cytoplasm, while eFE1A1 is translocated from the cytoplasm to the nucleus. Moreover, we find by Co-IP that TCE exposure significantly increases the interaction of SET with eEF1A2. Our data not only provide insights into the physiological functions of SET/TAF-Iα and complement the SET interaction networks, but also demonstrate that TCE exposure induces alterations in the expression, distribution and interactions of SET and its binding partners. These alterations may constitute the mechanisms of TCE cytotoxicity. Copyright © 2012 Elsevier Inc. All rights reserved.

Development of sensitive amperometric hydrogen peroxide sensor using a CuNPs/MB/MWCNT-C_6_0-Cs-IL nanocomposite modified glassy carbon electrode

International Nuclear Information System (INIS)

Roushani, Mahmoud; Bakyas, Kobra; Zare Dizajdizi, Behruz

2016-01-01

A sensitive hydrogen peroxide (H_2O_2) sensor was constructed based on copper nanoparticles/methylene blue/multiwall carbon nanotubes–fullerene–chitosan–ionic liquid (CuNPs/MB/MWCNTs–C_6_0–Cs–IL) nanocomposites. The MB/MWCNTs–C_6_0–Cs–IL and CuNPs were modified glassy carbon electrode (GCE) by the physical adsorption and electrodeposition of copper nitrate solution, respectively. The physical morphology and chemical composition of the surface of modified electrode was investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The electrochemical properties of CuNPs/MB/MWCNTs–C_6_0–Cs–IL/GCE were investigated by cyclic voltammetry (CV) and amperometry techniques and the sensor exhibited remarkably strong electrocatalytic activities toward the reduction of hydrogen peroxide. The peak currents possess a linear relationship with the concentration of H_2O_2 in the range of 0.2 μM to 2.0 mM, and the detection limit is 55.0 nM (S/N = 3). In addition, the modified electrode was used to determine H_2O_2 concentration in human blood serum sample with satisfactory results. - Highlights: • CuNPs/MB/MWCNT-C_6_0-Cs-IL/GC electrode was constructed by layer-by-layer method. • The catalytic performance of the sensor was studied with the use of amperometric technique. • The constructed sensor showed enhanced electrocatalytic activity toward the reduction of H_2O_2. • The CuNPs/MB/MWCNT-C_6_0-Cs-IL/GC electrode demonstrated high stability for the detection of H_2O_2.

Development of sensitive amperometric hydrogen peroxide sensor using a CuNPs/MB/MWCNT-C{sub 60}-Cs-IL nanocomposite modified glassy carbon electrode

Energy Technology Data Exchange (ETDEWEB)

Roushani, Mahmoud, E-mail: mahmoudroushani@yahoo.com; Bakyas, Kobra; Zare Dizajdizi, Behruz

2016-07-01

A sensitive hydrogen peroxide (H{sub 2}O{sub 2}) sensor was constructed based on copper nanoparticles/methylene blue/multiwall carbon nanotubes–fullerene–chitosan–ionic liquid (CuNPs/MB/MWCNTs–C{sub 60}–Cs–IL) nanocomposites. The MB/MWCNTs–C{sub 60}–Cs–IL and CuNPs were modified glassy carbon electrode (GCE) by the physical adsorption and electrodeposition of copper nitrate solution, respectively. The physical morphology and chemical composition of the surface of modified electrode was investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The electrochemical properties of CuNPs/MB/MWCNTs–C{sub 60}–Cs–IL/GCE were investigated by cyclic voltammetry (CV) and amperometry techniques and the sensor exhibited remarkably strong electrocatalytic activities toward the reduction of hydrogen peroxide. The peak currents possess a linear relationship with the concentration of H{sub 2}O{sub 2} in the range of 0.2 μM to 2.0 mM, and the detection limit is 55.0 nM (S/N = 3). In addition, the modified electrode was used to determine H{sub 2}O{sub 2} concentration in human blood serum sample with satisfactory results. - Highlights: • CuNPs/MB/MWCNT-C{sub 60}-Cs-IL/GC electrode was constructed by layer-by-layer method. • The catalytic performance of the sensor was studied with the use of amperometric technique. • The constructed sensor showed enhanced electrocatalytic activity toward the reduction of H{sub 2}O{sub 2}. • The CuNPs/MB/MWCNT-C{sub 60}-Cs-IL/GC electrode demonstrated high stability for the detection of H{sub 2}O{sub 2}.

The effect of ZnO or TiO{sub 2} loaded nanoparticles on the adsorption and photocatalytic performance of Cu-BTC and ZIF-8 MOFs

Energy Technology Data Exchange (ETDEWEB)

Ökte, A.N., E-mail: okteayse@boun.edu.tr [Department of Chemistry, Boğaziçi University, Bebek, 34342, Istanbul (Turkey); Karamanis, D.; Chalkia, E. [Department of Environmental & Natural Resources Management, University of Patras, 30100, Agrinio (Greece); Tuncel, D. [Department of Chemistry, Boğaziçi University, Bebek, 34342, Istanbul (Turkey)

2017-02-01

Binary composites of ZnO or TiO{sub 2} nanocatalysts on Cu-BTC and ZIF-8 were characterized and tested for the decolorization of methylene blue (MB) and methyl orange (MO). X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) images evidenced the creation of catalyst nanoparticles. Composites with higher dark adsorption capacities facilitated the decolorization rates of the dye molecules. MB decolorization percentages increased in the presence of Cu-BTC supported composites. ZnO addition increased the photoactivities of ZIF-8 composites for both MB and MO. - Highlights: • Dark adsorption capacities affect the photoactivities of the composites. • Cu-BTC based composites show higher degradation efficiencies toward MB. • ZnO addition enhance the photoactivity of 0.25 M ZnO-ZIF-8 for both MB and MO.

Microwave study of the high-T/sub c/ superconductor La/sub 1.8/Sr/sub 0.2/CuO4

International Nuclear Information System (INIS)

Poirier, M.; Quirion, G.; Poeppelmeier, K.R.; Thiel, J.P.

1987-01-01

High-T/sub c/ superconductivity is investigated by a microwave-cavity perturbation technique in the compound La/sub 1.8/Sr/sub 0.2/CuO 4 . Both the microwave loss and frequency shift show a rapid decrease at 39 K, the onset of the superconducting transition. A significant microwave absorption is also observed well below the transition. The data are used to determine the sample resistivity in the normal state and characterize the superconducting transition in an applied magnetic field

Defect chemistry and oxygen transport of (La0.6Sr0.4 − xMx)0.99Co0.2Fe0.8O3 − δ, M = Ca (x = 0.05, 0.1), Ba (x = 0.1, 0.2), Sr: Part II: Oxygen transport

DEFF Research Database (Denmark)

Dalslet, Bjarke Thomas; Søgaard, Martin; Hendriksen, Peter Vang

2009-01-01

This paper is the second part of a two part series, where the effects of varying the A-site dopant on the defect chemistry and transport properties of the materials (La0.6Sr0.4 − xMx)0.99Co0.2Fe0.8O3 − δ, M = Sr, Ca (x = 0.05, 0.1), Ba (x = 0.1, 0.2) (LSMFC) have been investigated. In part I......, the findings on the defect chemistry were reported, while the oxygen transport properties are reported here in part II. In the investigated material series, the amount of divalent dopant has been kept constant, while Sr ions have been substituted with Ca ions (smaller ionic radius) or Ba ions (larger ionic...... electrolyte probe were used to extract the permeability and surface resistance, rs. The highest permeability was found for (La0.6Sr0.3Ca0.1)0.99Co0.2Fe0.8O3 − δ. The apparent activation energy of the permeability was 78 kJ/mol. The inverse surface resistance, rs− 1, also had an activated behavior...

Phase stability and oxygen non-stoichiometry of SrCo0.8Fe0.2O3-d measured by in-situ neutron diffraction

NARCIS (Netherlands)

McIntosh, Steven; McIntosh, S.; Vente, Jaap F.; Haije, Wim G.; Blank, David H.A.; Bouwmeester, Henricus J.M.

2006-01-01

The phase stability, oxygen stoichiometry and expansion properties of SrCo0.8Fe0.2O3−δ (SCF) were determined by in situ neutron diffraction between 873 and 1173 K and oxygen partial pressures of 5×10−4 to 1 atm. At a pO2 of 1 atm, SCF adopts a cubic perovskite structure, space group Pm3¯m, across

Highly active La0.4Sr0.6Co0.8Fe0.2O3-δ nanocatalyst for oxygen reduction in intermediate temperature-solid oxide fuel cells

Science.gov (United States)

Chanquía, Corina M.; Mogni, Liliana; Troiani, Horacio E.; Caneiro, Alberto

2014-12-01

Pure-phase La0.4Sr0.6Co0.8Fe0.2O3-δ (LSCF) nanocrystallites were successfully synthesized by the combustion method, by employing glycine as fuel and complexing agent, and ammonium nitrate as combustion trigger. The morphological and structural characterization of the LSCF nanopowders was performed by using X-ray diffraction, N2 physisorption and electron microscopy. The LSCF nanopowder consists of interconnected nanocrystallites (∼45 nm) forming a sponge-like structure with meso and macropores, being its specific surface area around 10 m2 g-1. Crystalline structural analyses show that the LSCF nanopowder presents cubic symmetry in the Pm-3m space group. By employing the spin coating technique and different thermal treatments, symmetrical cells with different electrode crystallite size (45 and 685 nm) were built, by using La0.8Sr0.2Ga0.8Mg0.2O3-δ as electrolyte. Electrochemical impedance spectroscopy measurements were performed varying temperature and pO2. The area specific resistance of the nanostructured sample (45 nm) decreases by two orders of magnitude with respect to the submicrostructured sample (685 nm), reaching values as low as 0.8 Ω cm2 at 450 °C. This improvement is attributed to the cathode morphology optimization in the nanoscale, i.e., enlargement of the exposed surface area and shortening of the oxygen diffusion paths, which reduce the polarization resistance associated to the surface exchange and O-ion bulk diffusion process.

MDT-MB therapy in paucibacillary leprosy: A clinicopathological assessment

Directory of Open Access Journals (Sweden)

Prasad P

2005-01-01

Full Text Available BACKGROUND: The World Health Organization recommends treatment regimens for paucibacillary (PB and multibacillary (MB leprosy, which differ in their duration and components. Hence accurate classification of the disease is required. To overcome difficulties in classification Uniform Multi Drug Therapy (U-MDT has been recommended. AIM : To evaluate the benefit of adding clofazimine to paucibacillary regimens in leprosy patients by measuring clinical and histological resolution. METHODS: Forty-four paucibacillary patients were included in the study. Twenty-two patients were given MDT-PB regimen and the remaining MDT-MB regimen for six months . Skin biopsies were done before the commencement and at the end of treatment. Clinical and histological resolutions were measured according to the standard criteria a laid down. The results were analyzed using Fishers′ test and Crammers′ V test. RESULTS: Clinical improvement was observed in 90.9% in the MB group as compared to 27.3% in the PB group. Regression in the nerve swelling was observed in 70% in the MB group and in 37.5% in the PB group while histological resolution was observed in 72.8% and 54.5% respectively. CONCLUSIONS: Addition of clofazimine helps to resolve leprosy lesions both clinically and histologically, thus justifying the concept of Uniform MDT regimen for all patients.

Anisotropic bonded Sm2.3Fe16.8Zr0.2Ny magnets prepared by milling of as cast material

International Nuclear Information System (INIS)

Gebel, B.; Kubis, M.; Roessler, U.K.; Mueller, K.H.

2001-01-01

As cast Sm 2.3 Fe 16.8 Zr 0.2 material was milled for 100 min ≤ t ≤ 900 min. After annealing at 800 C for 1 h and subsequent nitrogenation, the samples were cold compacted in a magnetic field and resin bonded. The coercivity μ 0J H C of the samples increased from 0.59 T (t = 100 min) to 2.18 T (t = 900 min). On the other hand, the remanence along the texture axis decreased monotonically with increasing milling time due to the decrease of the degree of texture of the aligned powders. Prolonged milling leads finally to the formation of a soft magnetic phase as indicated by a shoulder in the demagnetization curve for t > 600 min. The highest energy product (BH) max of 50 kJm -3 (136 kJm -3 for the theoretical density of 7.7 gcm -3 ) was obtained for an intermediate milling time of 400 min. Zn bonding of the powders resulted in magnets with lower energy products but improved coercivities. (orig.)

Recently Quenched Galaxies at z = 0.2–4.8 in the COSMOS UltraVISTA Field

Energy Technology Data Exchange (ETDEWEB)

Ichikawa, Akie; Matsuoka, Yoshiki, E-mail: ichikawa@cosmos.phys.sci.ehime-u.ac.jp [Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)

2017-07-01

We present a new analysis of the stellar mass function and morphology of recently quenched galaxies (RQGs), whose star formation has been recently quenched for some reason. The COSMOS2015 catalog was exploited to select those galaxies at 0.2 < z < 4.8, over 1.5 deg{sup 2} of the Cosmic Evolution Survey (COSMOS) UltraVISTA field. This is the first time that RQGs are consistently selected and studied in such a wide range of redshift. We find increasing number density of RQGs with time in a broad mass range at z > 1, while low-mass RQGs start to grow very rapidly at z < 1. We also demonstrate that the migration of RQGs may largely drive the evolution of the stellar mass function of passive galaxies. Moreover, we find that the morphological type distribution of RQGs are intermediate between those of star-forming and passive galaxies. These results indicate that RQGs represent a major transitional phase of galaxy evolution, in which star-forming galaxies turn into passive galaxies, accompanied by the build up of spheroidal component.

Transport characteristic in current-in-plane (CIP) geometry of La0.8Sr0.2MnO3/Co heterostructure

International Nuclear Information System (INIS)

Jin, K.X.; Zhao, S.G.; Chen, C.L.

2009-01-01

The thousand-fold change in the resistance with increase in temperature has been observed in the current-in-plane (CIP) geometry of the La 0.8 Sr 0.2 MnO 3 /Co heterostructure prepared using a sol-gel method. The CIP geometry below 300 K exhibits the variable-range hopping (VRH) mechanism. The current-voltage characteristic is nonlinear and the fitting shows that the exponent n decreases with increasing the temperature, which is attributed to the lattice mismatch between the LSMO film and the Co substrate.

Effect of Sr substituted La 2−x Sr x NiO 4+δ (x = 0, 0.2, 0.4, 0.6, and 0.8) on oxygen stoichiometry and oxygen transport properties

KAUST Repository

Inprasit, T.; Wongkasemjit, S.; Skinner, S. J.; Burriel, M.; Limthongkul, P.

2015-01-01

© The Royal Society of Chemistry 2015. Stoichiometry and oxygen diffusion properties of La2-xSrxNiO4±δ with x = 0.2, 0.4, 0.6, and 0.8 prepared via a sol-gel method were investigated in this study. Iodometric titration and thermogravimetric analysis were used to determine the oxygen non-stoichiometry. Over the entire compositional range, the samples exhibit oxygen hyperstoichiometry with the minimum value δ = 0.14 at x = 0.4. Mixed effects of reduction of oxygen excess and increasing valence of Ni were found to serve as charge compensation mechanisms; the former dominated at a low level of substitution, x < 0.4, while the latter dominated at higher levels of Sr (0.4 < x < 0.8). The highest oxygen diffusion coefficient was found for the minimum amount of Sr substitution, x = 0.2, continuously decreasing with x until x = 0.6. An unusual increase in D∗ was observed when the Sr content increased up to x = 0.8.

Deep levels in as-grown and Si-implanted In(0.2)Ga(0.8)As-GaAs strained-layer superlattice optical guiding structures

Science.gov (United States)

Dhar, S.; Das, U.; Bhattacharya, P. K.

1986-01-01

Trap levels in about 2-micron In(0.2)Ga(0.8)As(94 A)/GaAs(25 A) strained-layer superlattices, suitable for optical waveguides, have been identified and characterized by deep-level transient spectroscopy and optical deep-level transient spectroscopy measurements. Several dominant electron and hole traps with concentrations of approximately 10 to the 14th/cu cm, and thermal ionization energies Delta-E(T) varying from 0.20 to 0.75 eV have been detected. Except for a 0.20-eV electron trap, which might be present in the In(0.2)Ga(0.8)As well regions, all the other traps have characteristics similar to those identified in molecular-beam epitaxial GaAs. Of these, a 0.42-eV hole trap is believed to originate from Cu impurities, and the others are probably related to native defects. Upon Si implantation and halogen lamp annealing, new deep centers are created. These are electron traps with Delta-E(T) = 0.81 eV and hole traps with Delta-E(T) = 0.46 eV. Traps occurring at room temperature may present limitations for optical devices.

Structural and magnetic properties of Ni0.8M0.2Fe2O4 (M = Cu, Co) nano-crystalline ferrites

Science.gov (United States)

Vijaya Babu, K.; Satyanarayana, G.; Sailaja, B.; Santosh Kumar, G. V.; Jalaiah, K.; Ravi, M.

2018-06-01

Nano-crystalline nickel ferrites are interesting materials due to their large physical and magnetic properties. In the present work, two kinds of spinel ferrites Ni0.8M0.2Fe2O4 (M = Cu, Co) are synthesized by using sol-gel auto-combustion method and the results are compared with NiFe2O4. The structural properties of synthesized ferrites are determined by using X-ray powder diffraction; scanning electron microscope and Fourier transform infrared spectroscopy. The cation distribution obtained from X-ray diffraction show that cobalt/copper occupies only tetrahedral site in spinel lattice. The lattice constant increases with the substitution of cobalt/copper. The structural parameters like bond lengths, tetrahedral and octahedral edges have been varied with the substitution. The microstructural study is carried out by using SEM technique and the average grain size is increased with nickel ferrite. The initial permeability (μi) is improving with the substitution. The observed g-value from ESR is approximately equal to standard value.

Measurement of the energy spectrum of the neutrons inside the neutron flux trap assembled in the center of the reactor core IPEN/MB-01

Energy Technology Data Exchange (ETDEWEB)

Bitelli, Ulysses d' Utra; Mura, Luiz Ernesto Credidio; Santos, Diogo Feliciano dos; Jerez, Rogerio; Mura, Luis Felipe Liamos, E-mail: ubitelli@ipen.br, E-mail: credidiomura@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

This paper presents the neutron energy spectrum in the central position of a neutron flux trap assembled in the core center of the research nuclear reactor IPEN/MB-01 obtained by an unfolding method. To this end, have been used several different types of activation foils (Au, Sc, Ti, Ni, and plates) which have been irradiated in the central position of the reactor core (setting number 203) at a reactor power level of 64.57 ±2.91 watts . The activation foils were counted by solid-state detector HPGe (gamma spectrometry). The experimental data of nuclear reaction rates (saturated activity per target nucleus) and a neutron spectrum estimated by a reactor physics computer code are the main input data to get the most suitable neutron spectrum in the irradiation position obtained through SANDBP code: a neutron spectra unfolding code that use an iterative adjustment method. The adjustment resulted in 3.85 ± 0.14 10{sup 9} n cm{sup -2} s{sup -1} for the integral neutron flux, 2.41 ± 0.01 10{sup 9} n cm{sup -2} s{sup -1} for the thermal neutron flux, 1.09 ± 0.02 10{sup 9} n cm{sup -2} s{sup -1} for intermediate neutron flux and 3.41± 0.02 10{sup 8} n cm{sup -2} s{sup -1} for the fast neutrons flux. These results can be used to verify and validate the nuclear reactor codes and its associated nuclear data libraries, besides show how much is effective the use of a neutron flux trap in the nuclear reactor core to increase the thermal neutron flux without increase the operation reactor power level. The thermal neutral flux increased 4.04 ± 0.21 times compared with the standard configuration of the reactor core. (author)

Structure refinement of Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-d} as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFC)

Energy Technology Data Exchange (ETDEWEB)

Zakaria, Nurhamidah, E-mail: nurhamidahzakaria@yahoo.com; Idris, Mohd Sobri, E-mail: sobri@unimap.edu.my [Centre of Excellence for Frontier Materials Research, School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), Taman Muhibbah, Jejawi 02600, Arau, Perlis (Malaysia); Osman, Rozana A. M., E-mail: rozana@unimap.edu.my [School of Microelectronics Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra, 02600, Arau, Perlis (Malaysia)

2016-07-19

Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-δ} was successfully prepared using modified solid-state synthesis routes. The lowest temperature to obtained single phase of Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-δ} is about 900°C for 15 hours. Longer period of time are required compared to only 5 hours at 950°C as established in literatures. The X-ray Diffraction (XRD) data confirmed that Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-δ} is formed a cubic perovskite with the space group of Pm-3m. The lattice parameters of Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-δ} are a = 3.990 (1) Å and unit cell volume is V = 63.5 (1) Å{sup 3}. The Rietveld refinement of XRD data revealed that the crystal structure of Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-δ} slightly changes as a function of temperature.

Comparison of structural and electric properties of PbZr0.2Ti0.8O3 and CoFe2O4/PbZr0.2Ti0.8O3 films on (100)LaAlO3

Science.gov (United States)

Zhang, X. D.; Dho, Joonghoe; Park, Sungmin; Kwon, Hyosang; Hwang, Jihwan; Park, Gwangseo; Kwon, Daeyoung; Kim, Bongju; Jin, Yeryeong; Kim, Bog. G.; Karpinsky, D.; Kholkin, A. L.

2011-09-01

In this work, we investigated structural, electrical, and magnetic properties of ferroelectric PbZr0.2Ti0.8O3 (PZT) and ferrimagnetic/ferroelectric [CoFe2O4(CFO)/PZT] bilayers grown on (100)LaAlO3 (LAO) substrates supplied with bottom 50 nm thick LaNiO3 electrodes. Interestingly, structural and electrical properties of the PZT layer exhibited remarkable changes after the top-layer CFO deposition. X-ray diffraction data suggested that both the c- and a-domains exist in the PZT layer and the tetragonality of the PZT decreases upon the top-layer deposition. A variation in the electrical properties of the PZT layer upon the CFO deposition was investigated by polarization versus voltage (P-V), capacitance versus voltage (C-V), and capacitance versus frequency (C-f) measurements. The CFO deposition induced a slight decrease of the remnant polarization and more symmetric behavior of P-V loops as well as led to the improvement of fatigue behavior. The tentative origin of enhanced fatigue endurance is discussed based on the measurement results. These results were corroborated by local piezoelectric measurements. Ferrimagnetic property of the CFO/PZT bilayer was confirmed by magnetic measurement at room temperature.

High-resolution array CGH clarifies events occurring on 8p in carcinogenesis

International Nuclear Information System (INIS)

Cooke, Susanna L; Pole, Jessica CM; Chin, Suet-Feung; Ellis, Ian O; Caldas, Carlos; Edwards, Paul AW

2008-01-01

Rearrangement of the short arm of chromosome 8 (8p) is very common in epithelial cancers such as breast cancer. Usually there is an unbalanced translocation breakpoint in 8p12 (29.7 Mb – 38.5 Mb) with loss of distal 8p, sometimes with proximal amplification of 8p11-12. Rearrangements in 8p11-12 have been investigated using high-resolution array CGH, but the first 30 Mb of 8p are less well characterised, although this region contains several proposed tumour suppressor genes. We analysed the whole of 8p by array CGH at tiling-path BAC resolution in 32 breast and six pancreatic cancer cell lines. Regions of recurrent rearrangement distal to 8p12 were further characterised, using regional fosmid arrays. FISH, and quantitative RT-PCR on over 60 breast tumours validated the existence of similar events in primary material. We confirmed that 8p is usually lost up to at least 30 Mb, but a few lines showed focal loss or copy number steps within this region. Three regions showed rearrangements common to at least two cases: two regions of recurrent loss and one region of amplification. Loss within 8p23.3 (0 Mb – 2.2 Mb) was found in six cell lines. Of the genes always affected, ARHGEF10 showed a point mutation of the remaining normal copies in the DU4475 cell line. Deletions within 12.7 Mb – 19.1 Mb in 8p22, in two cases, affected TUSC3. A novel amplicon was found within 8p21.3 (19.1 Mb – 23.4 Mb) in two lines and one of 98 tumours. The pattern of rearrangements seen on 8p may be a consequence of the high density of potential targets on this chromosome arm, and ARHGEF10 may be a new candidate tumour suppressor gene

A study on sintering aids for Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} electrolyte

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xinge; Deces-Petit, Cyrille; Yick, Sing; Robertson, Mark; Kesler, Olivera; Maric, Radenka; Ghosh, Dave [Institute for Fuel Cell Innovation, National Research Council Canada, 3250 East Mall, Vancouver, BC (Canada V6T 1W5)

2006-11-08

In this study, an addition of Co oxide or Cu oxide to Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (SDC) was studied to improve the sinterability of SDC. It has been found that both Co and Cu oxide are very effective as sintering aids, and the SDC sintering temperature can be reduced from 1400{sup o}C without aids to below 1000{sup o}C with only 1at.% of either Cu oxide or Co oxide. As compared to the pure SDC, a slight decrease of ionic conductivity was observed in SDC with Cu sintering aid. There is no obvious effect on electrochemical property of SDC with Co sintering aid under 2.5at.%. (author)

Empirical conversion between teleseismic magnitudes (mb and Ms) and moment magnitude (Mw) at the Global, Euro-Mediterranean and Italian scale

Science.gov (United States)

Lolli, B.; Gasperini, P.; Vannucci, G.

2014-11-01

use of the CSQ regression method, in place of the OLS, mitigates the bias and then, at low magnitudes, the EXP regression curve computed from the more complete MED data set almost coincides with that computed from the GBL data set. Our results also indicate that the slope at low magnitudes of the Mw-Ms relationship is substantially consistent with the hypothesized theoretical value of 2/3 for Ms < 5.0 while the slope of the Mw-mb relationship at high magnitudes probably reaches the theoretically expected value of 2 only in the proximity of the upper limit of mb determinations in our data set (mb = 7.2).

Calibration setting numbers for dose calibrators for the PET isotopes "5"2Mn, "6"4Cu, "7"6Br, "8"6Y, "8"9Zr, "1"2"4I

International Nuclear Information System (INIS)

Wooten, A. Lake; Lewis, Benjamin C.; Szatkowski, Daniel J.; Sultan, Deborah H.; Abdin, Kinda I.; Voller, Thomas F.; Liu, Yongjian; Lapi, Suzanne E.

2016-01-01

For PET radionuclides, the radioactivity of a sample can be conveniently measured by a dose calibrator. These devices depend on a “calibration setting number”, but many recommended settings from manuals were interpolated based on standard sources of other radionuclide(s). We conducted HPGe gamma-ray spectroscopy, resulting in a reference for determining settings in two types of vessels containing one of several PET radionuclides. Our results reiterate the notion that in-house, experimental calibrations are recommended for different radionuclides and vessels. - Highlights: • Dose calibrators measure radioactivity by ionization of gas from emitted radiation. • Accuracy of dose calibrators depends on “calibration setting numbers” for isotopes. • Many manufacturer settings are interpolated from emissions of other radionuclides. • As a high-precision reference, HPGe gamma-ray spectroscopy was conducted. • New calibrations were found for PET isotopes "5"2Mn, "6"4Cu, "7"6Br, "8"6Y, "8"9Zr, and "1"2"4I.

The effects of strain relaxation on the dielectric properties of epitaxial ferroelectric Pb(Zr0.2Ti0.8)TiO3 thin films

Science.gov (United States)

Khan, Asif Islam; Yu, Pu; Trassin, Morgan; Lee, Michelle J.; You, Long; Salahuddin, Sayeef

2014-07-01

We study the effects of strain relaxation on the dielectric properties of epitaxial 40 nm Pb(Zr0.2Ti0.8)TiO3 (PZT) films. A significant increase in the defect and dislocation density due to strain relaxation is observed in PZT films with tetragonality c/a fatigue in ferroelectric materials.

Mn0.8Zn0.2Fe2O4 nanoparticulates spinel ferrites: An approach to enhance the antenna field strength for improved magnitude versus offset (MVO

Directory of Open Access Journals (Sweden)

Majid Niaz Akhtar

2014-08-01

Full Text Available Electromagnetic signals in deep reservoir are very weak so that it is difficult to predict about the presence of hydrocarbon in seabed logging (SBL environment. In the present work, Mn0.8Zn0.2Fe2O4 nanoferrites were prepared by a sol–gel technique at different sintering temperatures of 450 °C, 650 °C and 850 °C to increase the strength of electromagnetic (EM antenna. XRD, FESEM, Raman spectroscopy and HRTEM were used to analyze the phase, surface morphology and size of the nanoferrites. Magnetic properties of the nanoferrites were also measured using an impedance network analyzer. However, nanoferrites sintered at 850 °C with initial permeability of 200 and Q factor of 50 were used as magnetic feeders with the EM antenna. Lab scale experiments were performed to investigate the effect of magnetic field strength in scale tank. SPSS and MATLAB softwares were also used to confirm the oil presence in scale tank. It was observed that the magnitude of the EM waves for the antenna was increased up to 233%. Finally, the correlation values also show 208% increase in the magnetic field strength with the presence of the oil. Therefore, antenna with Mn0.8Zn0.2Fe2O4 nanoferrites based magnetic feeders can be used for deep water and deep target hydrocarbon exploration.

Comprehensive detection of diverse exon 19 deletion mutations of EGFR in lung Cancer by a single probe set.

Science.gov (United States)

Bae, Jin Ho; Jo, Seong-Min; Kim, Hak-Sung

2015-12-15

Detection of exon 19 deletion mutation of EGFR, one of the most frequently occurring mutations in lung cancer, provides the crucial information for diagnosis and treatment guideline in non-small-cell lung cancer (NSCLC). Here, we demonstrate a simple and efficient method to detect various exon 19 deletion mutations of EGFR using a single probe set comprising of an oligo-quencher (oligo-Q) and a molecular beacon (MB). While the MB hybridizes to both the wild and mutant target DNA, the oligo-Q only binds to the wild target DNA, leading to a fluorescent signal in case of deletion mutation. This enables the comprehensive detection of the diverse exon 19 deletion mutations using a single probe set. We demonstrated the utility and efficiency of the approach by detecting the frequent exon 19 deletion mutations of EGFR through a real-time PCR and in situ fluorescence imaging. Our approach enabled the detection of genomic DNA as low as 0.02 ng, showing a detection limit of 2% in a heterogeneous DNA mixture, and could be used for detecting mutations in a single cell level. The present MB and oligo-Q dual probe system can be used for diagnosis and treatment guideline in NSCLC. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of the La0.8Sr0.2MnO3 films on STO and LAO substrates by excimer laser-assisted metal organic deposition using the KrF laser

International Nuclear Information System (INIS)

Tsuchiya, T.; Daoudi, K.; Manabe, T.; Yamaguchi, I.; Kumagai, T.

2007-01-01

La 0.8 Sr 0.2 MnO 3 films were prepared on SrTiO 3 (STO) and LaAlO 3 (LAO) substrates using excimer laser-assisted metal organic deposition (ELAMOD). For the LAO substrate, no epitaxial La 0.8 Sr 0.2 MnO 3 film was obtained by laser irradiation in the fluence range from 60 to 110 mJ/cm 2 with heating at 500 deg. C. On the other hand, an epitaxial La 0.8 Sr 0.2 MnO 3 film on the STO substrate was formed by laser irradiation in the fluence range from 60 to 100 mJ/cm 2 with heating at 500 deg. C. To optimize the electrical properties for an IR sensor, the effects of the laser fluence, the irradiation time and the film thickness on the temperature dependence of the resistance and temperature coefficient of resistance (TCR: defined as 1/R.(dR/dT)) of the LSMO films were investigated. An LSMO film on the STO substrate that showed the maximum TCR of 3.9% at 265 K was obtained by the ELAMOD process using the KrF laser

Cluster processing for 16Mb DRAM production

International Nuclear Information System (INIS)

Bergendahl, A.; Horak, D.

1989-01-01

Multichamber and in-situ technology are used to meet the challenge of manufacturing 16-Mb cost/performance DRAMs. The 16-Mb fabrication process is more complex than earlier 1-Mb and 4-Mb chips. Clustering of sequential process steps effectively compensates for both manufacturing complexity and foreign-material (FM) related defect densities. The development time of clusters combining new processes and equipment in multiple automated steps is nearly as long as the product development cycle. This necessitates codevelopment of manufacturing process cluster with technology integration while addressing the factors influencing FM defect generation, processing turnaround time (TAT), manufacturing costs, yield and array cell and support device designs. The advantages of multichamber and in situ processing have resulted in their application throughout the entire 16-Mb DRAM process as appropriate equipment becomes available

Anode-supported single-chamber solid oxide fuel cell based on cobalt-free composite cathode of Nd0.5Sr0.5Fe0.8Cu0.2O3-δ-Sm0.2Ce0.8O1.9 at intermediate temperatures

Science.gov (United States)

Yin, Jie-Wei; Zhang, Chunming; Yin, Yi-Mei; Shi, Huangang; Lin, Ye; Lu, Jun; Ma, Zi-Feng

2015-07-01

As a candidate of cathode material of single-chamber solid oxide fuel cell (SC-SOFC), cobalt-free mixed ionic electronic conductor (MIEC) Nd0.5Sr0.5Fe0.8Cu0.2O3-δ (NSFCu) is synthesized by sol-gel method with ethylene diamine tetraacetic acid and citric acid as co-complexing agents. The XRD shows NSFCu is stable after CO2 treatment and chemical compatible with SDC at high temperatures. CO2-TPD (CO2-temperature programmed desorption) demonstrates both CO2 adsorption and desorption phenomenon on NSFCu surface. However, the polarization resistances (Rp) of NSFCu and SDC (10:4 in weight) composite electrodes showed no decay in 5% CO2. Single cell using N2-O2-CH4 mixed gas (CH4 to O2 ratio = 1.5) as fuel shows maximum power density of 635 mW cm-2 at 700 °C. These results suggest that NSFCu-SDC is a promising composite cathode material for application in single-chamber solid oxide fuel cell.

Influence of body position on muscle deoxy[Hb+Mb] during ramp cycle exercise.

Science.gov (United States)

DiMenna, Fred J; Bailey, Stephen J; Jones, Andrew M

2010-09-30

We used near-infrared spectroscopy (NIRS) to test the hypothesis that body position alters the sigmoidal response profile of muscle fractional O(2) extraction (estimated using deoxy[Hb+Mb]) during incremental cycle exercise. Seven male subjects (mean±SD age 32±13 years) completed a ramp incremental cycling test to exhaustion (30W/min) in both the supine and upright body positions. The sigmoidal (as opposed to hyperbolic) model that provided the better fit to deoxy[Hb+Mb] data during upright cycling was also present for the supine response; however, the slope of the sigmoid was increased (upright: 0.052±0.012 vs. supine: 0.090±0.036%⋅%P(peak)(-1); Prate (upright: 83±8 vs. supine: 68±19%P(peak)(-1); Pchanges occurred in the absence of a leftward shift of the sigmoid. We also found a significantly greater deltaV(O)₂/deltaW slope above compared to below gas exchange threshold (GET) for both conditions (upright: 9.8±0.5 vs. 8.2±0.9; supine: 10.7±0.9 vs. 8.0±0.8) and for supine compared to upright cycling above GET. These findings suggest that the supine posture affects O₂ extraction and V(O)₂ kinetics to a greater extent as work rate progresses during ramp incremental exercise. Copyright 2010 Elsevier B.V. All rights reserved.

Polarization properties of La0.6Sr0.4Co0.2Fe0.8O3-based double layer-type oxygen electrodes for reversible SOFCs

International Nuclear Information System (INIS)

Tao, Y.; Nishino, H.; Ashidate, S.; Kokubo, H.; Watanabe, M.; Uchida, H.

2009-01-01

We have developed double layer-type (catalyst layer/current collecting layer) oxygen electrodes (DLE) for reversible SOFCs. As the catalyst layer (cathode for SOFC and anode for steam electrolysis) interfaced with a samaria-doped ceria [(CeO 2 ) 0.8 (SmO 1.5 ) 0.2 , SDC] interlayer/YSZ solid electrolyte, mixed conducting La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) and SDC particles were employed. The current collecting porous LSCF layer was formed on the catalyst layer. By controlling the SDC content, as well as the thickness and porosity of the catalyst layer, the gas diffusion rate and the conduction networks for electrons and oxide ions were optimized, resulting in a marked reduction of the overpotential. The LSCF + SDC/LSCF DLE exhibited higher performance than single-layer electrodes of LSCF + SDC or LSCF; the IR-free anode potential vs. an air reference electrode was 0.12 V (corresponding to an overpotential of 0.08 V) at 0.5 A cm -2 and 900 deg. C under an atmosphere of O 2 (1 atm)

Oxygen tracer diffusion and surface exchange kinetics in Ba0.5Sr0.5Co0.8Fe0.2O3-δ

NARCIS (Netherlands)

Berenov, A.; Atkinson, A.; Kilner, J.; Ananyev, M.; Eremin, V.; Porotnikova, N.; Farlenkov, A.; Kurumchin, E.; Bouwmeester, Henricus J.M.; Bucher, E.; Sitte, W.

2014-01-01

The oxygen tracer diffusion coefficient, Db⁎, and the oxygen tracer surface exchange coefficient, k, were measured in Ba0.5Sr0.5Co0.8Fe0.2O3 − δ (BSCF5582) over the temperature range of 310–800 °C and the oxygen partial pressure range of 1.3 × 10−3–0.21 bar. Several measurement techniques were used:

Human Sulfatase 2 inhibits in vivo tumor growth of MDA-MB-231 human breast cancer xenografts

International Nuclear Information System (INIS)

Peterson, Sarah M; Concino, Michael F; Liaw, Lucy; Martini, Paolo GV; Iskenderian, Andrea; Cook, Lynette; Romashko, Alla; Tobin, Kristen; Jones, Michael; Norton, Angela; Gómez-Yafal, Alicia; Heartlein, Michael W

2010-01-01

Extracellular human sulfatases modulate growth factor signaling by alteration of the heparin/heparan sulfate proteoglycan (HSPG) 6-O-sulfation state. HSPGs bind to numerous growth factor ligands including fibroblast growth factors (FGF), epidermal growth factors (EGF), and vascular endothelial growth factors (VEGF), and are critically important in the context of cancer cell growth, invasion, and metastasis. We hypothesized that sulfatase activity in the tumor microenvironment would regulate tumor growth in vivo. We established a model of stable expression of sulfatases in the human breast cancer cell line MDA-MB-231 and purified recombinant human Sulfatase 2 (rhSulf2) for exogenous administration. In vitro studies were performed to measure effects on breast cancer cell invasion and proliferation, and groups were statistically compared using Student's t-test. The effects of hSulf2 on tumor progression were tested using in vivo xenografts with two methods. First, MDA-MB-231 cells stably expressing hSulf1, hSulf2, or both hSulf1/hSulf2 were grown as xenografts and the resulting tumor growth and vascularization was compared to controls. Secondly, wild type MDA-MB-231 xenografts were treated by short-term intratumoral injection with rhSulf2 or vehicle during tumor growth. Ultrasound analysis was also used to complement caliper measurement to monitor tumor growth. In vivo studies were statistically analyzed using Student's t test. In vitro, stable expression of hSulf2 or administration of rhSulf2 in breast cancer cells decreased cell proliferation and invasion, corresponding to an inhibition of ERK activation. Stable expression of the sulfatases in xenografts significantly suppressed tumor growth, with complete regression of tumors expressing both hSulf1 and hSulf2 and significantly smaller tumor volumes in groups expressing hSulf1 or hSulf2 compared to control xenografts. Despite significant suppression of tumor volume, sulfatases did not affect vascular

Releasing metal catalysts via phase transition: (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 as a redox stable anode material for solid oxide fuel cells.

Science.gov (United States)

Xiao, Guoliang; Wang, Siwei; Lin, Ye; Zhang, Yanxiang; An, Ke; Chen, Fanglin

2014-11-26

Donor-doped perovskite-type SrTiO3 experiences stoichiometric changes at high temperatures in different Po2 involving the formation of Sr or Ti-rich impurities. NiO is incorporated into the stoichiometric strontium titanate, SrTi0.8Nb0.2O3-δ (STN), to form an A-site deficient perovskite material, (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 (Ni-STN), for balancing the phase transition. Metallic Ni nanoparticles can be released upon reduction instead of forming undesired secondary phases. This material design introduces a simple catalytic modification method with good compositional control of the ceramic backbones, by which transport property and durability of solid oxide fuel cell anodes are largely determined. Using Ni-STN as anodes for solid oxide fuel cells, enhanced catalytic activity and remarkable stability in redox cycling have been achieved. Electrolyte-supported cells with the cell configuration of Ni-STN-SDC anode, La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode produce peak power densities of 612, 794, and 922 mW cm(-2) at 800, 850, and 900 °C, respectively, using H2 as the fuel and air as the oxidant. Minor degradation in fuel cell performance resulted from redox cycling can be recovered upon operating the fuel cells in H2. Such property makes Ni-STN a promising regenerative anode candidate for solid oxide fuel cells.

Nickel-doped (Zr0.8, Sn0.2)TiO4 for microwave and millimeter-wave applications

International Nuclear Information System (INIS)

Ioachim, A.; Banciu, M.G.; Toacsan, M.I.; Nedelcu, L.; Ghetu, D.; Alexandru, H.V.; Stoica, G.; Annino, G.; Cassettari, M.; Martinelli, M.

2005-01-01

(Zr 0.8 , Sn 0.2 )TiO 4 ternary compounds (ZST) have been prepared by conventional solid-state reaction from raw materials. The effects of such sintering parameters as sintering temperature, sintering time, and NiO addition on structural and dielectric properties were investigated. The material exhibits a dielectric constant ε r ∼36.0 and high values of the product Qf of the intrinsic quality factor Q and the frequency f from 32,170 to 50,000 at microwave frequencies. The dielectric loss tan δ values of ZST ceramics are decreased by low-level doping of NiO, while the temperature coefficient of the resonance frequency τ f takes values in the range -2 to +4 ppm/ deg. C. Investigations on whispering gallery modes revealed low dielectric loss in millimetre-wave domain. An intrinsic quality factor of 480 was measured at 115.6 GHz. Dielectric resonators and substrates of ZST material were manufactured. The dielectric properties make the ZST material very attractive to microwave and millimeter-wave applications, such as dielectric resonators, filters, planar antennas, hybrid microwave integrated circuits, etc

Microstructure evolution and large magnetocaloric effect of La0.8Ce0.2(Fe0.95Co0.05)11.8Si1.2 alloy prepared by strip-casting and annealing

Science.gov (United States)

Zhong, X. C.; Feng, X. L.; Huang, J. H.; Zhang, H.; Huang, Y. L.; Liu, Z. W.; Jiao, D. L.

2018-04-01

The microstructure and magnetocaloric effect of the La0.8Ce0.2(Fe0.95Co0.05)11.8Si1.2 strip-cast flakes annealed between 1273K and 1423K for different time have been investigated. For the flakes annealed for 2h from 1273K to 1423K, the shape and distribution of α-Fe, La-rich and NaZn13-type 1:13 phases are quite sensitive to the annealing temperature. Especially, at a high annealing temperature of 1423K, the 1:13 phase began to decompose into macroscopic α-Fe conglomerations and La-rich dendrites. With the increase of annealing time from 0 to 12h at 1323K, the amount of 1:13 phase increased significantly and reached ˜93.50 wt.% at 12h. However, an overlong annealing time also led to 1:13 phase decomposition and influenced the magnetic performance. For the flakes annealed at 1323K for 12h, large magnetic entropy change value of 18.12Jkg-1K-1 at 5T has been obtained. The present results indicate that strip casting method can potentially be used in mass production of high performance magnetocaloric materials.

Structural and electrochemical properties of La 0.8Sr 0.2Ga 1-xFe xO 3

Science.gov (United States)

Mori, Kazuhiro; Onodera, Yohei; Kiyanagi, Ryoji; Richardson, James W.; Itoh, Keiji; Sugiyama, Masaaki; Kamiyama, Takashi; Fukunaga, Toshiharu

2009-02-01

Mixed ionic-electronic conductor of Fe doped lanthanum gallate, La 0.8Sr 0.2Ga 1-xFe xO 3, has been studied by the dc four-probe method and the neutron powder diffraction. In the electrical conductivity measurement at RT, insulator-metal transition-like phenomenon was observed at around x˜0.35; this suggests an existence of the percolation limit for the electronic conductivity. Simultaneously, a bond length between O atoms, lO-O, in a MO 6 octahedron (M dbnd Ga 1-xFe x) drastically expands over x˜0.4, according to the result of crystal structure refinement based on the hexagonal phase. Such a drastic expansion in the lO-O would induce the decrease in the oxygen ionic conductivity.

Development and application of graphite-SiO2/Al2O3/Nb2O5-methylene blue (GRP-SiAlNb-MB composite for electrochemical determination of dopamine

Directory of Open Access Journals (Sweden)

Juliana de Fátima Giarola

2017-03-01

Full Text Available In the present paper an amperometric sensor based on graphite-SiO2/Al2O3/Nb2O5-methylene blue (GRP-SiAlNb-MB composite has been successfully prepared for dopamine (DA determination in real samples. The electrochemical behavior of DA at the GRP-SiAlNb-MB has been evaluated by employing cyclic voltammetry. The best ratio (m/m of GRP-SiAlNb-MB composite was found to be 1:0.54. Under optimized conditions (pH 7.5 in 0.15 mol L−1 phosphate buffer the amperometry method responds linearly to DA from 5.0 up to 500.0 μmol L−1 (r = 0.995 with limits of detection and quantification of 1.49 and 4.97 μmol L−1, respectively. The developed method was successfully applied for DA determination in real samples of pharmaceutical formulations and can be used for routine quality control analysis of pharmaceutical formulations containing DA. The use of inorganic matrix SiAlNb was found to be very useful to adsorb MB in the composite material with further improvement of the anodic peak current of DA.

Mechanical behaviour of Br0.5Sr0.5Co0.8Fe0.2O3-δ under uniaxial compression

International Nuclear Information System (INIS)

Araki, Wakako; Malzbender, Jürgen

2013-01-01

The present study reports on the mechanical behaviour of Br 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ under uniaxial compression at various temperatures. The stress–strain curve at room temperature shows a small but clear creep deformation, along with a hysteresis and a remnant strain, which could be related to a spin transition of cobalt. The hysteresis as well as Young’s modulus decrease with increasing temperature to 473 K, at which temperature the creep behaviour disappears. The material shows conventional high-temperature creep above 673 K

Peak effect and superconducting properties of SmFeAsO{sub 0.8}F{sub 0.2} wires

Energy Technology Data Exchange (ETDEWEB)

Chen, Y L; Cui, Y J; Yang, Y; Zhang, Y; Wang, L; Zhao, Y [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, and Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C H; Sorrell, C [School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)], E-mail: yzhao@swjtu.edu.cn

2008-11-15

Ta-sheathed SmFeAsO{sub 0.8}F{sub 0.2} superconducting wires with T{sub c} = 52.5 K have been fabricated using the powder-in-tube (PIT) method and the superconducting properties of the wires have been investigated. The wires exhibit a very large intragrain critical current density at a temperature below 30 K. A peak effect with maximal J{sub c} = 0.6 MA cm{sup -2} at 10 K under 6 T field was observed. The peak field H{sub pear} is strongly temperature-dependent. A severe weak-link effect depresses the development of global supercurrent owing to a very short coherence length. The wires also show a power law temperature dependence for the irreversibility line with H{sub irr}{approx_equal}(1-T/T{sub c}){sup 1.5}. The H-T phase diagram was found to be similar to that of other superconducting cuprates.

Clinical utility of a two-site immunoradiometric assay for creatine kinase-MB in the detection of perioperative myocardial infarction

International Nuclear Information System (INIS)

DePuey, E.G.; Aessopos, A.; Monroe, L.R.; Hall, R.J.; Thompson, W.L.; Sonnemaker, R.E.; Burdine, J.A.

1983-01-01

In 144 patients, creatine kinase MB was measured serially at 0, 8, 16, 24, 48 and 72 h using a two-site immunoradionmetric assay (IRMA). Cardiac enzymes were also measured, including SGOT, LDH, total CPK, and CK-MB by electrophoresis. The presence of perioperative myocardial infarction (poMI) was established in 24 patients by the appearance of new electrocardiographic Q waves and/or new wall motion abnormalities detected by radionuclide ventriculography. In patients without poMI, CK-MB (IRMA) was elevated at 0 to 8 h but decreased by 16 h. In patients with poMI, peak values occurred at 16 to 24 h. Using a threshold value of 8.5 EU/I, patients with poMI could be distinguished from those without with 97% accuracy (sensitivity = 88%, specificity = 99%). We conclude that the CK-MB (IRMA) can serve as a valuable postoperative screening tet for poMI

Characterization of the yttria-stabilized zirconia thin film electrophoretic deposited on La0.8Sr0.2MnO3 substrate

International Nuclear Information System (INIS)

Yang, Koho; Shen, Jung-Hsiung; Yang, Kai-Yun; Hung, I-Ming; Fung, Kuan-Zong; Wang, Moo-Chin

2007-01-01

The yttria-stabilized zirconia (YSZ) thin films electrophoretic deposited on the La 0.8 Sr 0.2 MnO 3 (LSM) substrate have been characterized by using zeta potential analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The La 2 Zr 2 O 7 (LZ) formed at the interface between the YSZ thin film and LSM substrate, after sintered at 1400 o C for 52 h, are identified by XRD. The zeta potential of the YSZ particles in pure ethanol-acetone is about 7.8 mV, but when the I 2 concentration is greater than 0.6 g/1, the zeta potential attains a constant value, 46 mV. The relation between deposit weight of the YSZ films and the applied voltage shows a non-linear behavior. Thickness of the YSZ thin film deposited on the LSM substrate by electrophoretic deposition is controlled by a diffusion process. A larger LZ with the thickness of 200 nm is formed at the interface between the YSZ film and the LSM substrate

Effect of boron addition on the microstructures and electrochemical properties of MmNi3.8Co0.4Mn0.6Al0.2 electrode alloys prepared by casting and rapid quenching

International Nuclear Information System (INIS)

Zhang Yanghuan; Chen Meiyan; Wang Xinlin; Wang Guoqing; Lin Yufang; Qi Yan

2004-01-01

The rapid quenching technology was used in the preparation of the MmNi 3.8 Co 0.4 Mn 0.6 Al 0.2 B x (x=0, 0.1, 0.2, 0.3, 0.4) electrode alloys. The microstructures and electrochemical performances of the as-cast and quenched alloys were analysed and measured. The effects of boron additive on the microstructures and electrochemical properties of as-cast and quenched alloy MmNi 3.8 Co 0.4 Mn 0.6 Al 0.2 were investigated. The experimental results showed that the microstructure of as-cast MmNi 3.8 Co 0.4 Mn 0.6 Al 0.2 B x (x=0, 0.1, 0.2, 0.3, 0.4) alloy is composed of CaCu 5 -type main phase and a small amount of CeCo 4 B-type secondary phase. The abundance of the secondary phase increases with the increase of the boron content x. The secondary phase in the alloys disappears when quenching rate is larger than 22 m/s. The electrochemical measurement showed that the addition of boron slightly modifies the activation performance and dramatically enhances the cycle life of the alloys, whereas it reduces the capacities of the as-cast and quenched alloys. The influence of boron additive on the electrochemical characteristics of the as-quenched alloy is much stronger than that on the as-cast alloy. It is because boron strongly promotes the formation of the amorphous phase in the as-quenched alloy

The Influence of Deposition Methods of Support Layer on Cordierite Substrate on the Characteristics of a MnO2–NiO–Co3O4/Ce0.2Zr0.8O2/Cordierite Three Way Catalyst

Directory of Open Access Journals (Sweden)

Phuong Thi Mai Pham

2014-09-01

Full Text Available This paper compares different coating methods (in situ solid combustion, hybrid deposition, secondary growth on seed, suspension, double deposition of wet impregnation and suspension to deposit Ce0.2Zr0.8O2 mixed oxides on cordierite substrates, for use as a three way catalyst. Among them, the double deposition was proven to be the most efficient one. The coated sample shows a BET (Brunauer–Emmett–Teller surface area of 25 m2/g, combined with a dense and crack free surface. The catalyst with a layer of MnO2–NiO–Co3O4 mixed oxides on top of the Ce0.2Zr0.8O2/cordierite substrate prepared by this method exhibits good activity for the treatment of CO, NO and C3H6 in exhaust gases (CO conversion of 100% at 250 °C, C3H6 conversion of 100% at 400 °C and NO conversion of 40% at 400 °C.

F-theory and 2d (0,2) theories

Energy Technology Data Exchange (ETDEWEB)

Schäfer-Nameki, Sakura [Department of Mathematics, King’s College London, The Strand, London WC2R 2LS (United Kingdom); Weigand, Timo [Institut für Theoretische Physik, Ruprecht-Karls-Universität,Philosophenweg 19, 69120 Heidelberg (Germany)

2016-05-11

F-theory compactified on singular, elliptically fibered Calabi-Yau five-folds gives rise to two-dimensional gauge theories preserving N=(0,2) supersymmetry. In this paper we initiate the study of such compactifications and determine the dictionary between the geometric data of the elliptic fibration and the 2d gauge theory such as the matter content in terms of (0,2) superfields and their supersymmetric couplings. We study this setup both from a gauge-theoretic point of view, in terms of the partially twisted 7-brane theory, and provide a global geometric description based on the structure of the elliptic fibration and its singularities. Global consistency conditions are determined and checked against the dual M-theory compactification to one dimension. This includes a discussion of gauge anomalies, the structure of the Green-Schwarz terms and the Chern-Simons couplings in the dual M-theory supersymmetric quantum mechanics. Furthermore, by interpreting the resulting 2d (0,2) theories as heterotic worldsheet theories, we propose a correspondence between the geometric data of elliptically fibered Calabi-Yau five-folds and the target space of a heterotic gauged linear sigma-model (GLSM). In particular the correspondence between the Landau-Ginsburg and sigma-model phase of a 2d (0,2) GLSM is realized via different T-branes or gluing data in F-theory.

In situ neutralisation of the antibacterial effect of 0.2% Chlorhexidine on salivary microbiota: Quantification of substantivity.

Science.gov (United States)

Quintas, V; Prada-López, I; Donos, N; Suárez-Quintanilla, D; Tomás, I

2015-08-01

To quantify the substantivity of a single 0.2% Chlorhexidine mouthwash in saliva after its neutralisation with tooth-brushing and 1% acetic acid, in order to identify the effect of Chlorhexidine substantivity in regard to the re-growing period of the salivary bacteria. Unstimulated saliva samples were collected from a group of 15 healthy individuals at baseline (BS), and then 30s and 1, 3, 5 and 7h after the following protocols were performed: a single sterile water mouthwash (M-WATER) (negative control), a single 0.2% Chlorhexidine mouthwash (M-0.2% CHX) (positive control) and a single 0.2% Chlorhexidine mouthwash followed by a complete and detailed tooth-brushing, and a single 1% acetic acid mouthwash (M-0.2% CHX+NP). The samples were analysed using an epifluorescence microscope in combination with LIVE/DEAD(®) BacLight™ fluorescence solution. After the M-0.2% CHX treatment, the bacterial vitality was significantly lower than BS until 7h (87.6 ± 6.5% vs. 73.6 ± 8.8%; pvitality remained significantly lower until 3h with regard to BS (81.4 ± 3.8% vs. 68.1 ± 10.6%; p=0.001), increasing at 5 and 7h (no differences from BS). The immediate antibacterial effect of a single 0.2% Chlorhexidine mouthwash is so potent that the bacterial population needs more than 3h to return to baseline bacterial vitality levels. The substantivity of a 0.2% Chlorhexidine mouthwash is a property that significantly increases its antibacterial activity from the first hour and contributes to extend the duration of its effect by at least double. Copyright © 2015 Elsevier Ltd. All rights reserved.

Neutron diffraction and low temperature magnetization study of Tb0.8Y0.2MnO3

International Nuclear Information System (INIS)

Chakraborty, Keka R.; Mukadam, M.; Yusuf, S.M.; Shukla, R.; Tyagi, A.K.; Kaushik, S.D.; Siruguri, V.

2012-01-01

Multiferroic materials possess mutually correlated magnetic and electric order parameters which are suitable for device applications but scarcity of such materials and the separation of magnetic and electric ordering temperatures are a major hindrance in technological applications. TbMnO 3 is one of the material which is reported to have higher magnetoelectric coupling. Structurally, TbMnO 3 crystallizes in orthorhombically distorted perovskite structure (space group Pbnm). For TbMnO 3 , several reports are available in the literature which further modify the magnetoelectric coupling by selective doping or reducing the particle size to nano dimensions, or preparing thin films. Here, we study the effect of Y doping at Tb site in nanoparticle form in terms of crystal structure and magnetic properties. Nanoparticles of Tb 0.8 Y 0.2 MnO 3 were synthesized using the gel combustion technique. Crystal structure of this sample is studied at 300 K using neutron diffraction

Microstructure, crystal structure and electrical properties of Cu0.1Ni0.8Co0.2Mn1.9O4 ceramics obtained at different sintering conditions

International Nuclear Information System (INIS)

Bodak, O.; Akselrud, L.; Demchenko, P.; Kotur, B.; Mrooz, O.; Hadzaman, I.; Shpotyuk, O.; Aldinger, F.; Seifert, H.; Volkov, S.; Pekhnyo, V.

2002-01-01

Details of the formation of Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramics under different sintering conditions have been studied by optical microscopy, scanning electron microscopy (SEM), electron probe and energy dispersive spectroscopy (EDX) microanalyses, X-ray diffraction (XRD) and electrical resistivity measurements. Microstructure studies of samples sintered at 1170 deg. C for 1 h indicated the presence of a secondary phase besides the main spinel phase with modified composition. XRD measurements showed that the spinel phase exhibits a tetragonally distorted spinel structure (space group I4 1 /amd, a=5.9410(5) A, c=8.4196(15) A). The secondary phase (solid solution based on NiO) crystallizes with the NaCl-type structure (space group Fm3-bar m, a=4.1872(3) A). The content of the secondary phase in ceramics is 10.61 mass%. For NiMn 2 O 4 ceramics, prepared under the same sintering conditions, the decomposition with Ni 1-x Mn x O solid solution (NaCl-type structure) and spinel phase formation have been observed. The tetragonal modification of the spinel phase for NiMn 2 O 4 ceramics is more preferable (space group I4 1 /amd, a=5.9764(5) A, c=8.4201(8) A). The distribution of atoms in the structure has been proposed for both ceramics. According to XRD results the Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramic samples, sintered at 920 deg. C for 8 h (program 1), at 920 deg. C for 8 h and at 750 deg. C for 24 h (program 2), at 920 deg. C for 8 h, at 1200 deg. C for 1 h and at 920 deg. C for 24 h (program 3) and at 920 deg. C for 8 h, at 1200 deg. C for 1 h, at 920 deg. C for 24 h and at 750 deg. C for 48 h (program 4), contain a single phase with the cubic spinel structure (space group Fd3-bar m). Small residuals of the secondary phase for the ceramics, prepared via programs 3 and 4, have been observed by SEM investigations. The structure transformations of the spinel phase for Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramics sintered at 1170 deg. C are attributed to a Jahn

Synthesize and electrochemical characterization of Mg-doped Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 cathode material

International Nuclear Information System (INIS)

Wang, Dan; Huang, Yan; Huo, Zhenqing; Chen, Li

2013-01-01

Highlights: • Layered Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 (2x = 0, 0.01, 0.02, 0.05) were synthetized. • Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 exhibit enhanced electrochemical properties. • The improved performance is attributed to enhanced structure stability. -- Abstract: Mg-doped Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 as a Li-rich cathode material of lithium-ion batteries were prepared by co-precipitation method and ball-milling treatment using Mg(OH) 2 as a dopant. Scanning electron microscopy (SEM), ex situ X-ray powder diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvantatic charge/discharge were used to investigate the effect of Mg doping on structure and electrochemical performance. Compared with the bare material, Mg-doped materials exhibit better cycle stabilities and superior rate capabilities. Li[Li 0.2 Ni 0.195 Mn 0.595 Mg 0.01 ]O 2 displays a high reversible capacity of 226.5 mAh g −1 after 60 cycles at 0.1 C. The excellent cycle performance can be attributed to the improvement in structure stability, which is verified by XRD tests before and after 60 cycles. EIS results show that Mg doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance

Defect chemistry and oxygen transport of (La0.6Sr0.4-xMx)(0.99)Co0.2Fe0.8O3-delta, M = Ca (x=0.05, 0.1), Ba (x=0.1, 0.2), Sr Part I: Defect chemistry

DEFF Research Database (Denmark)

Dalslet, Bjarke Thomas; Søgaard, Martin; Bouwmeester, Henry J.M.

2009-01-01

This paper is the first part of a two part series, where the effects of varying the A-site dopant on the defect chemistry, the diffusion coefficient and the surface catalytic properties of the materials (La0.6Sr0.4 − xMx)0.99Co0.2Fe0.8O3 − δ, M = Sr, Ca (x = 0.05, 0.1), Ba (x = 0.1, 0.2) (LSMFC......) have been investigated. In part I, the findings on the defect chemistry are reported, while the transport properties are reported in part II. Substitution of Sr2+ ions with Ca2+ ions (smaller ionic radius) and Ba2+ ions (larger ionic radius) strains the crystal structure differently for each...... composition while keeping the average valence of the cations constant. The Ba2+ containing materials show the largest oxygen loss at elevated temperatures, while the purely Sr2+ doped material showed the smallest oxygen loss. This was reflected in the partial oxidation entropy of the materials. The measured...

Serum dosage of CPK-MB in dogs with ST deviation by chemiluminescence

Directory of Open Access Journals (Sweden)

André L.F. Santos

2014-12-01

Full Text Available Abstract: Although frequently in humans, hypoxic and ischemic heart diseases are poorly documented in dogs, with only few reports of acute myocardial infarction (AMI in this species. Some electrocardiographic findings might suggest myocardium hypoxia/ischemia, like ST segment elevation or depression, but there are no studies showing whether deviations in ST segment are associated to myocardial injury and serum increase of creatine phosphokinase (CPK-MB. In order to investigate possible myocardial cells injury in poor perfusion conditions, 38 dogs were studied, 20 with normal electrocardiogram and 18 with ST segment elevation or depression, recorded in lead II, at a paper speed of 50 mm/sec and N sensibility (1mV=1cm. Serum measurement of creatine phosphokinase isoenzyme MB (CPK-MB in normal dogs (group 1 determined control values (in ng/mL, which were compared to those obtained from dogs with deviation (group 2, which allowed confirmation or not of myocardial injury. CPK-MB mean values obtained from dogs in groups 1 and 2 were 0.540ng/ml (SD±0.890ng/mL and 0.440ng/mL (SD±1.106, respectively. At a significance level of 5%, the relation of CPK-MB with age, mass and total creatine phosphokinase (CPK-T was not significant in groups 1 and 2. CPK-MB showed no difference, at 5% level, between groups 1 and 2. In conclusion, it is possible to use the human chemiluminescent immunometric assay kit in canine species and that hypoxia/ischemia revealed by ST segment deviation does not mean significant myocardium injury.

Raman Scattering in La0.2Sr0.8FeO3-δ thin film: annealing-induced reduction and phase transformation

Science.gov (United States)

Islam, Mohammad; Xie, Yujun; Scafetta, Mark; May, Steven; Spanier, Jonathan

2015-03-01

Raman scattering in thin film La0.2Sr0.8FeO3-δ on MgO(001) collected at 300 K following different stages of annealing at selected temperatures (300 K topotactic transformation of the crystal structure from that of the rhombohedral ABO3 perovskites to that of Brownmillerite-like structure consisting of octahedrally and tetrahedrally coordinated Fe atoms. We acknowledge the ONR (N00014-11-1-0664), the Drexel Centralized Research Facilities, the Army Research Office DURIP program, the Department of Education (GAANN-RETAIN, Award No. P200A100117), and Leszek Wielunski at Rutgers University.

Reactivity and neutron flux measurements in IPEN/MB-01 reactor with B4C burnable poison

International Nuclear Information System (INIS)

Fer, Nelson Custodio; Moreira, Joao Manoel Losada

2000-01-01

Burnable poison rods, made of B 4 C- Al 2 O 3 pellets with 5.01 mg/cm 3 10 B concentration, have been manufactured for a set of experiments in the IPEN/MB-01 zero-power reactor. Several core parameters which are affected by the burnable poisons rods have been measured. The principal results, for the situation in which the burnable poison rods are located near the absorber rods of a control rod, are they cause a 29% rod worth shadowing, a reduction of 39% in the local void coefficient of reactivity, a reduction of 4.8% in the isothermal temperature coefficient of reactivity, and a reduction of 9% in the thermal neutron flux in the region where the burnable poison rods are located. These experimental results will be used for the validation of burnable poison calculation methods in the CTMSP. (author)

Reactivity effect of a heavy water tank as reflector in the IPEN/MB-01 reactor

International Nuclear Information System (INIS)

Santos, Adimir dos; Fuga, Rinaldo

2013-01-01

This experiment comprises a set of experiments performed in the IPEN/MB-01 reactor and described in the International Handbook of Evaluated Reactor Physics Benchmark Experiments, specifically the experiment aim to evaluate the reactivity due to the heavy water tank placed at reflector region of the IPEN/MB-01 reactor. An aluminum tank was designed to be filled with heavy water and positioned at the west face of the IPEN/MB-01, additionally the experiment was also designed to allow variable heavy water height inside of this tank providing different neutron leakage rate in the west face of the IPEN/MB-01, consequently providing a series of interesting combinations. The measured quantities in the experiment are reactivities and critical control bank positions for several combinations of the control banks and an excess of reactivity of the heavy water tank. The experiment will be simulated using a Monte Carlo code MCNP in order to compare the different critical control bank position. (author)

Lattice defects in semiconducting Hg/1-x/Cd/x/Te alloys. I - Defect structure of undoped and copper doped Hg/0.8/Cd/0.2/Te. II - Defect structure of indium-doped Hg/0.8/Cd/0.2/Te

Science.gov (United States)

Vydyanath, H. R.

1981-01-01

Hall effect and mobility measurements were conducted on undoped Hg(0.8)Cd(0.2)Te crystals which were quenched to room temperature after being subjected to equilibration at temperatures ranging from 400 to 655 C in various Hg atmospheres. The variation of the hole concentration in the cooled crystals at 77 K as a function of Hg's partial pressure at the equilibration temperature, together with a comparison of the hole mobility in the undoped samples with that in copper-doped ones, yields a defect model for the undoped crystals according to which they are intrinsic at the equilibration temperatures and the native acceptor defects are doubly ionized. In the second part of this paper, the effects of indium doping are considered. The concentration of electrons obtained in the cooled crystals was found to be lower than the intrinsic carrier concentration at the equilibration temperatures. A defect model is proposed according to which most of the indium is incorporated as In2Te3(s) dissolved in the crystal, with only a small fraction of indium acting as single donors occupying Hg lattice sites.

Generation of an approximately 2.4 Mb human X centromere-based minichromosome by targeted telomere-associated chromosome fragmentation in DT40.

Science.gov (United States)

Mills, W; Critcher, R; Lee, C; Farr, C J

1999-05-01

A linear mammalian artificial chromosome (MAC) will require at least three types of functional element: a centromere, two telomeres and origins of replication. As yet, our understanding of these elements, as well as many other aspects of structure and organization which may be critical for a fully functional mammalian chromosome, remains poor. As a way of defining these various requirements, minichromosome reagents are being developed and analysed. Approaches for minichromosome generation fall into two broad categories: de novo assembly from candidate DNA sequences, or the fragmentation of an existing chromosome to reduce it to a minimal size. Here we describe the generation of a human minichromosome using the latter, top-down, approach. A human X chromosome, present in a DT40-human microcell hybrid, has been manipulated using homologous recombination and the targeted seeding of a de novo telomere. This strategy has generated a linear approximately 2.4 Mb human X centromere-based minichromosome capped by two artificially seeded telomeres: one immediately flanking the centromeric alpha-satellite DNA and the other targeted to the zinc finger gene ZXDA in Xp11.21. The chromosome retains an alpha-satellite domain of approximately 1. 8 Mb, a small array of gamma-satellite repeat ( approximately 40 kb) and approximately 400 kb of Xp proximal DNA sequence. The mitotic stability of this minichromosome has been examined, both in DT40 and following transfer into hamster and human cell lines. In all three backgrounds, the minichromosome is retained efficiently, but in the human and hamster microcell hybrids its copy number is poorly regulated. This approach of engineering well-defined chromosome reagents will allow key questions in MAC development (such as whether a lower size limit exists) to be addressed. In addition, the 2.4 Mb minichromosome described here has potential to be developed as a vector for gene delivery.

Synthesis, characterization and magnetic properties of MWCNTs decorated with Zn-substituted MnFe{sub 2}O{sub 4} nanoparticles using waste batteries extract

Energy Technology Data Exchange (ETDEWEB)

Gabal, M.A., E-mail: mgabalabdonada@yahoo.com [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Al-Harthy, E.A. [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80216, Jeddah 21589 (Saudi Arabia); Al Angari, Y.M.; Abdel Salam, M.; Asiri, A.M. [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia)

2016-06-01

Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.2–0.8) nano-crystals, synthesized from recycling of Zn–C batteries, were successfully self-assembled alongside multi-walled carbon nanotubes (MWCNTs) via an environmentally friend sucrose auto-combustion method. The effect of Zn-content on structural and magnetic properties were investigated and discussed. XRD revealed the formation of single-phase ferrites. DTA–TG experiment showed that the auto-combustion reaction finished at about 350 {sup °}C. TEM exhibited that the MWCNTs are well decorated with ferrite particles. Hysteresis loop measurements revealed ferromagnetic behavior, with saturation magnetization decrease by the addition of MWCNTs or increasing Zn-Content. The kinetics of methylene blue dye (MB) removal using MWCNTs/Mn{sub 0.8}Zn{sub 0.2}Fe{sub 2}O nano-composite was investigated and discussed. - Graphical abstract: TEM image of MWCNTs/Mn{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nano-composite showed that the MWCNTs were completely decorated with magnetic nanoparticles. The decoration passed through nucleation and growth processes in which nucleation of ferrite nanoparticles first takes place on the surface of MWCNTs followed by a subsequent growth of these nuclei. - Highlights: • Mn-Zn-ferrites were obtained via recycling process of spent Zn-C batteries. • Mn1−xZnxFe2O4/MWCNTS nano-composites were synthesized via sucrose combustion route. • Zn-substitution effect on structural and magnetic properties was investigated. • MWCNTs/Mn0.8Zn0.2Fe2O4 was investigated to remove MB dye from aqueous media.

Osteoporose bei Mb. Bechterew - neue Ansätze

Directory of Open Access Journals (Sweden)

Obermayer-Pietsch B

1999-01-01

Full Text Available Eine axiale Osteoporose und daraus resultierende vertebrale Kompressionsfrakturen sind häufige Symptome eines Mb. Bechterew (MbB, Spondylarthritis ankylosans. Als ein möglicher genetischer Faktor der Osteoporose wurde eine Assoziation der Knochendichte (BMD mit BsmI- und FokI-Polymorphismen im Vitamin D-Rezeptor-(VDR-Gen publiziert. In der vorliegenden Studie wurden die Beziehungen zwischen diesen Polymorphismen, Knochenstoffwechsel, BMD und Aktivitätsindizes bei Patienten mit MbB untersucht. Bei 47 MbB-Patienten wurden Aktivitätsindizes und morphologische Parameter sowie BMD-Messungen (Dual-Röntgen-Absorptiometrie an Wirbelsäule und Schenkelhals im Vergleich zu 52 gesunden, altersgleichen Personen erhoben. Die Laborbestimmungen umfaßten biochemische Aktivitätsparameter, HLA-Typisierung sowie Knochenan- und -abbaumarker. Aus peripheren Leukozyten wurde genomische DNA präpariert und mittels Polymerase-Kettenreaktion (PCR und anschließender FokI- und BsmI-Restriktion der VDR-Genotyp nach vorhandenen bzw. fehlenden Schnittstellen (f/b bzw. F/B bestimmt. Bei MbB-Patienten fand sich eine Osteoporose deutlich häufiger als in der Kontrollgruppe. Eine Zuordnung von Aktivitätsindizes, BMD und Knochenstoffwechselparametern zu den Genotypen zeigte bei männlichen MbB-Patienten sowohl eine Assoziation der WS-Knochendichte als auch der Entzündungsmarker mit FokI-, nicht jedoch mit BsmI-Genotypen des VDR. Die pathophysiologischen Mechanismen dieser Assoziation, insbesondere mit der entzündlichen Aktivität des Mb. Bechterew, sind noch ungeklärt. Eine frühzeitige Erfassung des Osteoporoserisikos bei MbB-Patienten mittels molekularbiologischer Tests könnte eine rechtzeitige Prophylaxe und Therapie dieser Komplikation ermöglichen.

Electrochemical Properties of the LiNi0.6Co0.2Mn0.2O2 Cathode Material Modified by Lithium Tungstate under High Voltage.

Science.gov (United States)

Fu, Jiale; Mu, Daobin; Wu, Borong; Bi, Jiaying; Cui, Hui; Yang, Hao; Wu, Hanfeng; Wu, Feng

2018-05-31

An amount (5 wt %) of lithium tungstate (Li 2 WO 4 ) as an additive significantly improves the cycle and rate performances of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrode at the cutoff voltage of 4.6 V. The 5 wt % Li 2 WO 4 -mixed LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrode delivers a reversible capacity of 199.2 mA h g -1 and keeps 73.1% capacity for 200 cycles at 1 C. It retains 67.4% capacity after 200 cycles at 2 C and delivers a discharge capacity of 167.3 mA h g -1 at 10 C, while those of the pristine electrode are only 44.7% and 87.5 mA h g -1 , respectively. It is shown that the structure of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode material is not affected by mixing Li 2 WO 4 . The introduced Li 2 WO 4 effectively restrains the LiPF 6 and carbonate solvent decomposition by consuming PF 5 at high cutoff voltage, forming a stable cathode/electrolyte interface film with low resistance.

Vibrational localized motions of hydrogen in the storage compound Ti0.8 Zr0.2 CrMnH3 studied by slow neutron inelastic scattering

International Nuclear Information System (INIS)

Mestnik Filho, J.; Vinhas, L.A.

1988-08-01

The vibrational localized motions of hydrogen in the storage compound Ti 0.8 Zr 0.2 CrMnH 3 have been studied by slow neutron scattering, utilizing a berilium-filter-time-of-flight spectrometer. An energy distribution, consisting of therre peaks 50 MeV wide (FWHM), corresponding to the energy transfer of 85, 115 and 141 MeV has been observed and was attributed to hydrogen localized vibrations in three types of interstices which differs in composition of Ti and Zr atoms. From the analysis of the observed peaks intensities, it was concluded that the lowest measured hydrogen vibrational frequency is correlated with interstices that are rich in zirconium atoms whereas the highest frequency is due o interstices rich in titanium atoms. Therefore the larger radius of the the Zr atoms leads to the formation of interstices with larger intersticial hole sizes, which, in turn, makes possible the absorption of hydrogen in this compound, in contrast to an isostructural compound which contains only atoms with smaller radii, like Ti, in place of the atomic group Ti 0.8 Zr 0.2 . (author) [pt

Microstructure and magnetic properties of nanostructured (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} alloy produced by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Boukherroub, N. [UR-MPE, M' hamed Bougara University, Boumerdes 35000 (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399 Alger-Gare, Algiers (Algeria); Laggoun, A. [UR-MPE, M' hamed Bougara University, Boumerdes 35000 (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399 Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Souami, N. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399 Alger-Gare, Algiers (Algeria); Gorria, P. [Department of Physics and IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Bourzami, A. [Laboratoire d' Etudes des Surfaces et Interfaces des Matériaux Solides (LESIMS), Université Sétif1, 19000 Sétif (Algeria); Lenoble, O. [Institut Jean Lamour, CNRS-Université de Lorraine, Boulevard des aiguillettes, BP 70239, F-54506 Vandoeuvre lès Nancy (France)

2015-07-01

We report on how the microstructure and the silicon content of nanocrystalline ternary (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} powders (x=0, 5, 10, 15 and 20 at%) elaborated by high energy ball milling affect the magnetic properties of these alloys. The formation of a single-phase alloy with body centred cubic (bcc) crystal structure is completed after 72 h of milling time for all the compositions. This bcc phase is in fact a disordered Fe(Al,Si) solid solution with a lattice parameter that reduces its value almost linearly as the Si content is increased, from about 2.9 Å in the binary Fe{sub 80}Al{sub 20} alloy to 2.85 Å in the powder with x=20. The average nanocrystalline grain size also decreases linearly down to 10 nm for x=20, being roughly half of the value for the binary alloy, while the microstrain is somewhat enlarged. Mössbauer spectra show a sextet thus suggesting that the disordered Fe(Al,Si) solid solution is ferromagnetic at room temperature. However, the average hyperfine field diminishes from 27 T (x=0) to 16 T (x=20), and a paramagnetic doublet is observed for the powders with higher Si content. These results together with the evolution of both the saturation magnetization and the coercive field are discussed in terms of intrinsic and extrinsic properties. - Highlights: • Single-phase nanocrystalline (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} (x=0, 5, 10, 15 and 20 at%) powders were successfully fabricated by mechanical alloying for a milling time of 72 h. • The insertion of Si atoms leads to a unit-cell contraction and a decrease in the average crystallite size. • The hyperfine and magnetic properties of (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} were influenced by the Si content.

Synthesis of Li{sub 2}Si{sub 2}O{sub 5}-coated LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} cathode materials with enhanced high-voltage electrochemical properties for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Liu, Shengjie; Wu, Hao; Huang, Ling; Xiang, Mingwu; Liu, Heng; Zhang, Yun, E-mail: y_zhang@scu.edu.cn

2016-07-25

Ni-rich ternary layered oxides, (LiNi{sub x} [M]{sub 1−x}O{sub 2}, x ≥ 0.5, M = Co and Mn), have become one of the mainstream cathode materials for next-generation lithium-ion batteries due to their high capacity and cost efficiency compared with LiCoO{sub 2}. However, the high-voltage operation of the Ni-rich oxides (>4.3 V) required for high capacity is inevitably accompanied with a rapid capacity decay over numerous cycles. In this work, we reported a surface coating of LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} with Li{sub 2}Si{sub 2}O{sub 5}via a facile and efficient synthetic approach, which involves the employment of silicic acid (H{sub 2}SiO{sub 3}) as remover to react with the surface residual lithium compounds (e.g. Li{sub 2}CO{sub 3} and LiOH) of LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} and consequent formation of a robust and complete Li{sup +}-conductive Li{sub 2}Si{sub 2}O{sub 5} protective coating layer. The structure and morphology of the coated cathode materials are fully characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Compared with the pristine LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2}, coating with the Li{sup +}-conductive Li{sub 2}Si{sub 2}O{sub 5} is found to be very effective for improving the rate capability of the LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} when evaluated at a high cut-off voltage up to 4.5 V. Specifically, 1 wt. % H{sub 2}SiO{sub 3}-treated LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} electrode exhibits high discharge specific capacities of 213.9 and 121.6 mAh g{sup −1} at 0.1 and 10 C, respectively, whereas the pristine electrode only shows 196.8 and 92.1 mAh g{sup −1}. Besides, the surface-modified LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} electrode also manifests an enhanced long-term cycling stability (67% capacity retention after 200 cycles at 5 C), much better than the pristine

DC-8 MTP calibration for SOLVE-2

Science.gov (United States)

Mahoney, M. J.

2003-01-01

The Jet Propulsion Laboratory (JPL) Microwave Temperature Profiler (MTP) was the only instrument making temperature measurements at and below flight level on the DC-8 during the SOLVE-2 campaign. Many years of careful comparison of MTP measurements with radiosondes near the DC-8 flight track have shown that the flight level temperature can be determined to an accuracy of 0.2K relative to radiosondes.

Osteoporose bei Mb. Bechterew - neue Ansätze

OpenAIRE

Obermayer-Pietsch B; Aglas F; Hermann J; Leb G; Tauber G

1999-01-01

Eine axiale Osteoporose und daraus resultierende vertebrale Kompressionsfrakturen sind häufige Symptome eines Mb. Bechterew (MbB, Spondylarthritis ankylosans). Als ein möglicher genetischer Faktor der Osteoporose wurde eine Assoziation der Knochendichte (BMD) mit BsmI- und FokI-Polymorphismen im Vitamin D-Rezeptor-(VDR-)Gen publiziert. In der vorliegenden Studie wurden die Beziehungen zwischen diesen Polymorphismen, Knochenstoffwechsel, BMD und Aktivitätsindizes bei Patienten mit MbB untersuc...

High performance Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}-La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.15}Co{sub 0.05}O{sub 3} composite cathodes

Energy Technology Data Exchange (ETDEWEB)

Wang, Shizhong; Zou, Yuman [College of Chemistry and Chemical Engineering, Department of Chemistry, Xiamen University, Xiamen 361005, Fujian (China)

2006-06-15

High performance Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}(SSC)-La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.15}Co{sub 0.05}O{sub 3} (LSGMC5) composite cathodes for intermediate temperature solid oxide fuel cells (ITSOFC) were prepared and characterized. The SSC powders were synthesized using the glycine-nitrate method and La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.15}Co{sub 0.05}O{sub 3}(LSGMC5) powders were synthesized using the citrate method. The calcining temperature for the SSC and LSGMC5 powders had strong effect on the microstructure of the composite electrode and electrode/electrolyte interface, which affected the performance of the SSC-LSGMC5 electrode strongly. The electrode based on SSC calcined at 1223K and LSGMC5 calcined at 1273K exhibited the highest performance among the electrodes studied. The electrode resistance was about 0.07{omega}cm{sup 2}, and the overpotential under 1Acm{sup -2} current density was as low as 0.077V at 973K in oxygen, which could be an ideal cathode for ITSOFC based on lanthanum gallate electrolytes. (author)

MeB5O8(Me-Li, Na, K, NH4)-H2NCONHCOCH3-H2O system at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Fedorov, Yu.A.; Molodkin, A.K.; Tsekhanskij, R.S.

1986-01-01

Using the methods of isothermal solubility, densi- and refractometry, systems MB 5 O 8 (M-Li, Na, K, NH 4 )-acetylcarbamide - H 2 O at 25 deg C have been studied. It is ascertained, that the systems investigated are of simple eutonic type

Effect of Manganese Addition on the Structure, Magnetic Properties and Microwave Absorption of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3

Science.gov (United States)

Adi, W. A.; Indro, M. N.; Kusumastuti, A. A.

2017-03-01

We have carried out modification of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3 (x = 0.1 - 0.8) magnetic materials by wet milling method. Raw materials of La2O3, BaCO3, Fe2O3, TiO2 and MnCO3 were mixed according to stoichiometry calculation for each composition. The mixture was milled for 5 hours and then sintered at 1000 °C for 5 hours. The refinement results by X-ray diffraction pattern shows that the increasing Mn composition enhances the mass fraction of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3 phase which has the same structure as LaMnO3. For x = 0.8 a single phase of LaMnO3 was formed. The single phase has a crystal monoclinic crystal structure with space group of I 1 2 / a 1, with lattice parameters given by a = 5.519(5) Å, b = 5.5537(5) Å and c = 7.8176(9) Å, α = γ = 90o and β = 90.345(6)o, V = 239.64(3) Å3, ρ = 6.463 gr.cm-3, wRp = 5.96, and χ2 (chi-squared) = 1.17. The hysteresis curve shows that the sample with composition x = 0.8 produces ferromagnetic behaviour at room temperature. The ferromagnetic properties arise due to the mixed valence of Mn3+ and Mn4+ ions through a double exchange mechanism. The results of the microwave absorption indicated that there was a broadening of absorption peak frequency at 9.9 GHz. The reflection loss (RL) increases with the increasing of LaMnO3 phase. For x = 0.8 we have the best of RL where the microwave absorption was calculated reaching 95% at the highest peak frequency with a thickness of 1.5 mm. Thus we have been successful in creating a single phase of La0.8Ba0.2MnxFe½(1-x)Ti½(1-x)O3 with application as a microwave absorber.

Constitutive Equation and Hot Compression Deformation Behavior of Homogenized Al–7.5Zn–1.5Mg–0.2Cu–0.2Zr Alloy

Directory of Open Access Journals (Sweden)

Jianliang He

2017-10-01

Full Text Available The deformation behavior of homogenized Al–7.5Zn–1.5Mg–0.2Cu–0.2Zr alloy has been studied by a set of isothermal hot compression tests, which were carried out over the temperature ranging from 350 °C to 450 °C and the strain rate ranging from 0.001 s−1 to 10 s−1 on Gleeble-3500 thermal simulation machine. The associated microstructure was studied using electron back scattered diffraction (EBSD and transmission electron microscopy (TEM. The results showed that the flow stress is sensitive to strain rate and deformation temperature. The shape of true stress-strain curves obtained at a low strain rate (≤0.1 s−1 conditions shows the characteristic of dynamic recrystallization (DRX. Two Arrhenius-typed constitutive equation without and with strain compensation were established based on the true stress-strain curves. Constitutive equation with strain compensation has more precise predictability. The main softening mechanism of the studied alloy is dynamic recovery (DRV accompanied with DRX, particularly at deformation conditions, with low Zener-Holloman parameters.

Evidence for non-exponential elastic proton–proton differential cross-section at low |t| and s=8TeV by TOTEM

Directory of Open Access Journals (Sweden)

G. Antchev

2015-10-01

Full Text Available The TOTEM experiment has made a precise measurement of the elastic proton–proton differential cross-section at the centre-of-mass energy s=8 TeV based on a high-statistics data sample obtained with the β⁎=90 m optics. Both the statistical and systematic uncertainties remain below 1%, except for the t-independent contribution from the overall normalisation. This unprecedented precision allows to exclude a purely exponential differential cross-section in the range of four-momentum transfer squared 0.027<|t|<0.2 GeV2 with a significance greater than 7 σ. Two extended parametrisations, with quadratic and cubic polynomials in the exponent, are shown to be well compatible with the data. Using them for the differential cross-section extrapolation to t=0, and further applying the optical theorem, yields total cross-section estimates of (101.5±2.1 mb and (101.9±2.1 mb, respectively, in agreement with previous TOTEM measurements.

Fe3O4@SiO2@CS-TETA functionalized graphene oxide for the adsorption of methylene blue (MB) and Cu(II)

Science.gov (United States)

Wang, Fan; Zhang, Lijuan; Wang, Yeying; Liu, Xijian; Rohani, Sohrab; Lu, Jie

2017-10-01

The graphene oxide (GO) functionalized by Fe3O4@SiO2@CS-TETA nanoparticles, Fe3O4@SiO2@CS-TETA-GO, was firstly fabricated in a mild way as a novel adsorbent for the removal of Cu(II) ions and methylene blue (MB) from aqueous solutions. The magnetic composites showed a good dispersity in water and can be conveniently collected for reuse through magnetic separation due to its excellent magnetism. When the Fe3O4@SiO2@CS- TETA-GO was used as an absorbent for the absorption of MB and Cu(II), the adsorption kinetics and isotherms data well fitted the pseudo-second-order model and the Langmuir model, respectively. Under the optimized pH and initial concentration, the maximum adsorption capacity was about 529.1 mg g-1 for MB in 20 min and 324.7 mg g-1 for Cu(II) in 16 min, respectively, exhibiting a better adsorption performance than other GO-based adsorbents reported recently. More importantly, the synthesized adsorbent could be effectively regenerated and repeatedly utilized without significant capacity loss after six times cycles. All the results demonstrated that Fe3O4@SiO2@CS-TETA-GO could be used as an excellent adsorbent for the adsorption of Cu(II) and MB in many fields.

Charge disproportionation in (X0.6Sr0.4)0.99Fe0.8Co0.2O3-δ perovskites (X = La, Pr, Sm, Gd)

DEFF Research Database (Denmark)

Pedersen, Thomas; Saadi, Souheil; Nielsen, K.H.

2005-01-01

The change in crystal structure and the oxidation state in iron of iron-cobalt-based perovskites with different A-site cations is investigated by the use of powder XRD and Mossbauer spectroscopy. The perovskites investigated are (X0.6Sr0.4)(0.99)Fe0.8Co0.2O3-delta, where X is La, Pr, Sm or Gd...

Vortex dynamics and irreversibility line in optimally doped SmFeAsO0.8F0.2 from ac susceptibility and magnetization measurements

Science.gov (United States)

Prando, G.; Carretta, P.; de Renzi, R.; Sanna, S.; Palenzona, A.; Putti, M.; Tropeano, M.

2011-05-01

Ac susceptibility and static magnetization measurements were performed in the optimally doped SmFeAsO0.8F0.2 superconductor. The field-temperature phase diagram of the superconducting state was drawn, and, in particular, the features of the flux lines were derived. The dependence of the intragrain depinning energy on the magnetic field intensity was derived in the thermally activated flux-creep framework, enlightening a typical 1/H dependence in the high-field regime. The intragrain critical current density was extrapolated in the zero-temperature and zero-magnetic-field limit, showing a remarkably high value Jc0(0)~2×107 A/cm2, which demonstrates that this material is rather interesting for potential future technological applications.

Intermediate-to-low temperature protonic ceramic membrane fuel cells with Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}}-BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} composite cathode

Energy Technology Data Exchange (ETDEWEB)

Lin, Bin; Ding, Hanping; Dong, Yingchao; Wang, Songlin; Zhang, Xiaozhen; Fang, Daru; Meng, Guangyao [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)

2009-01-01

The perovskite-type Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}}-BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BSCF-BZCY) composite oxides were synthesized by a modified Pechini method and examined as a novel composite cathode for intermediate-to-low temperature protonic ceramic membrane fuel cells (ILT-PCMFCs). Thin proton-conducting BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BZCY) electrolyte and NiO-BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (NiO-BZCY) anode functional layer were prepared over porous anode substrates composed of NiO-BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} by a one-step dry-pressing/co-firing process. A laboratory-sized quad-layer cell of NiO-BZCY/NiO-BZCY({proportional_to}50 {mu}m)/BZCY({proportional_to}20 {mu}m)/BSCF-BZCY({proportional_to}50 {mu}m) was operated from 550 to 700 C with humidified hydrogen ({proportional_to}3% H{sub 2}O) as fuel and the static air as oxidant. A high open-circuit potential of 1.009 V, a maximum power density of 418 mW cm{sup -2}, and a low polarization resistance of the electrodes of 0.10 {omega} cm{sup 2} was achieved at 700 C. These investigations have indicated that proton-conducting BZCY electrolyte with BSCF perovskite cathode is a promising material system for the next generation solid oxide fuel cells (SOFCs). (author)

Efficiency and safety of transfer of type 2 diabetes patients inadequately controlled on metformin alone to combined therapy with metformin and diabeton MB

Directory of Open Access Journals (Sweden)

Alexander Sergeevich Ametov

2009-12-01

Full Text Available Aim. To evaluate efficiency and tolerability of diabeton MB/metformin combination in patients failing to achieve optimal glycemic control when onmetformin monotherapy and prove advantages of this combination over combined low-dose therapy with glibenclamide and metformin. Materials and methods. The study included 464 patients with type 2 diabetes mellitus who poorly responded to metformin monotherapy. It was supplementedby diabeton MB. Efficiency and tolerability of combined treatment was evaluated from dynamics of glycemia and frequency of side-effects.40 patients were included in detailed comparative assessment (laboratory and instrumental, CGMS of this monotherapy and fixed low-dose combinationof glibenclamide with metformin. Results. Results of comparison show that diabeton MB/metformin combination ensured most optimal glycemic control with a minimal risk of side effects. Conclusion. Diabeton MB/metformin combination is convenient, efficient and safe.

The effect of MgO doping on the structure, magnetic and magnetotransport properties of La0.8Sr0.2MnO3 composite

International Nuclear Information System (INIS)

Aezami, A.; Eshraghi, M.; Kameli, P.; Salamati, H.

2007-01-01

Full text: The recent observation of anomalously Colossal Magnetoresistance (CMR) in the La 1-x A x MnO 3 (A = Sr, Ca, Ba or vacancies) system, has spurred renewed interest in studying these doped perovskite manganites. The properties of these materials are explained by double exchange theory of Zener and electron lattice interaction. However, the intrinsic CMR effect in the perovskite manganites is found on a magnetic field scale of several teslas and a narrow temperature range. It was found that, the presence of grain boundaries in polycrystalline samples leads to a large Low Field Magnetoresistance (LFMR) effect over a wide temperature range below the Curie temperature Tc. To achieve LFMR, different properties are considered. One of them is mixing of these CMR materials with secondary insulator phases. In this work, La 0.8 Sr 0.2 MnO 3 (LSMO) was selected as matrix material and MgO as a dopant. The La 0.8 Sr 0.2 MnO 3/x MgO samples with x= 0, 1, 2, 3, 5 and 7.5 Wt.% were prepared by Solid State Reaction method. Studies show that most part of the MgO goes into the perovskite lattice and Mg substituted Mn in LSMO and remainder segregates as a separate phase at the grain boundaries. Results also show that the value of MR decreases for all the doping levels. It seems that, due to the almost same ionic radii of Mg2+ and Mn2+, and at the higher sintering temperature, Mg2+ mostly replaced Mn3+ and weakens double exchange interaction. This speculation has been confirmed by XRD, SEM, susceptibility, resistivity and magnetoresistance analysis and measurements. (authors)

Molten salt synthesis of La0.8Sr0.2MnO3 powders for SOFC cathode electrode

Science.gov (United States)

Gu, Sin-il; Shin, Hyo-soon; Hong, Youn-woo; Yeo, Dong-hun; Kim, Jong-hee; Nahm, Sahn; Yoon, Sang-ok

2012-08-01

For La0.8Sr0.2MnO3 (LSM) perovskite, used as the cathode material for solid oxide fuel cells (SOFC), it is known that the formation of a triple-phase-boundary is restrained due to the formation of a second phase at the YSZ/electrode interface at high temperature. To decrease the 2nd phase, lowering the sintering temperature has been used. LSM powder was synthesized by molten salt synthesis method to control its particle size, shape, and agglomeration. We have characterized the phase formation, particle size, shape, and sintering behavior of LSM in the synthesis using the variation of KCl, LiCl, KF and its mixed salts as raw materials. In the case of KCl and KCl-KF salts, the particle size and shape of the LSM was well controlled and synthesized. However, in the case of LiCl and KCl-LiCl salts, LiMnOx as 2nd phase and LSM were synthesized simultaneously. In the case of the mixed salt of KCl-KF, the growth mechanism of the LSM particle was changed from `diffusion-controlled' to `reaction-controlled' according to the amount of mixed salt. The sintering temperature can be decreased below 1000 °C by using the synthesized LSM powder.

Electrical transport properties of CoMn0.2−xGaxFe1.8O4 ferrites using complex impedance spectroscopy

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Chien-Yie Tsay

2016-05-01

Full Text Available In this study, we report the influence of Ga content on the microstructural, magnetic, and AC impedance properties of Co-based ferrites with compositions of CoMn0.2−xGaxFe1.8O4 (x=0, 0.1, and 0.2 prepared by the solid-state reaction method. Experimental results showed that the as-prepared Co-based ferrites had a single-phase spinel structure; the Curie temperature of Co-based ferrites decreased with increasing Ga content. All ferrite samples exhibited a typical hysteresis behavior with good values of saturation magnetization at room temperature. The electrical properties of Co-based ferrites were investigated using complex impedance spectroscopy analysis in the frequency range of 100 kHz-50 MHz at temperatures of 150 to 250 oC. The impedance analysis revealed that the magnitudes of the real part (Z’ and the imaginary part (Z” of complex impedance decreased with increasing temperature. Only one semicircle was observed in each complex impedance plane plot, which revealed that the contribution to conductivity was from the grain boundaries. It was found that the relaxation time for the grain boundary (τgb also decreased with increasing temperature. The values of resistance for the grain boundary (Rgb significantly increased with increasing Ga content, which indicated that the incorporation of Ga into Co-based ferrites enhanced the electrical resistivity.

A Golay complementary TS-based symbol synchronization scheme in variable rate LDPC-coded MB-OFDM UWBoF system

Science.gov (United States)

He, Jing; Wen, Xuejie; Chen, Ming; Chen, Lin

2015-09-01

In this paper, a Golay complementary training sequence (TS)-based symbol synchronization scheme is proposed and experimentally demonstrated in multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband over fiber (UWBoF) system with a variable rate low-density parity-check (LDPC) code. Meanwhile, the coding gain and spectral efficiency in the variable rate LDPC-coded MB-OFDM UWBoF system are investigated. By utilizing the non-periodic auto-correlation property of the Golay complementary pair, the start point of LDPC-coded MB-OFDM UWB signal can be estimated accurately. After 100 km standard single-mode fiber (SSMF) transmission, at the bit error rate of 1×10-3, the experimental results show that the short block length 64QAM-LDPC coding provides a coding gain of 4.5 dB, 3.8 dB and 2.9 dB for a code rate of 62.5%, 75% and 87.5%, respectively.

Synthesis and electrocatalytic properties of La0.8Sr0.2FeO3−δ perovskite oxide for oxygen reactions

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R.A. Silva

2017-09-01

Full Text Available Perovskites are important alternatives for precious metals as catalysts for bifunctional oxygen electrodes, involving oxygen evolution (OER and reduction (ORR reactions as is the case of regenerative fuel cells. In this work, strontium doped lanthanum ferrite La1−xSrxFeO3−δ (x = 0; 0.1; 0.2; 0.3; 0.4; 0.6 and 1.0 powders were prepared by a self-combustion route. The oxides, in the form of carbon paste electrodes, were characterised by cyclic voltammetry in alkaline solutions. Data analyses lead to the selection of La0.8Sr0.2FeO3−δ to prepare gas diffusion electrodes (GDEs. Cyclic voltammetry and steady state polarization curves were used, respectively, to assess the electrochemical behaviour of GDEs and to obtain kinetic data for both OER and ORR. It is concluded that the oxide preparation conditions/electrode configuration determine the electrode performance. The bifunctionality of the electrodes was assessed, under galvanostatic control, using a cycling protocol within the potential domains for OER and ORR. The potential window, i.e., the total combined overpotential between OER and ORR was found to be of ≈770 mV, value which compares well with that obtained under potentiostatic control. Even though the potential window keeps constant during 140 cycles, the increase in cycling time and/or current density (≥2.5 mA·cm−2 led to a gradual metallization of the GDE surface, as confirmed by Scanning Electron Microscopy and X-ray diffraction analysis.

Association Mapping of Ferrous, Zinc, and Aluminum Tolerance at the Seedling Stage in Indica Rice using MAGIC Populations

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Lijun Meng

2017-10-01

Full Text Available Excessive amounts of metal are toxic and severely affect plant growth and development. Understanding the genetic control of metal tolerance is crucial to improve rice resistance to Fe, Zn, and Al toxicity. The multi-parent advanced generation inter-cross (MAGIC populations were genotyped using a 55 K rice SNP array and screened at the seedling stage for Fe, Zn, and Al toxicity using a hydroponics system. Association analysis was conducted by implementing a mixed linear model (MLM for each of the five MAGIC populations double cross DC1 (founders were SAGC-08, HHZ5-SAL9-Y3-Y1, BP1976B-2-3-7-TB-1-1, PR33282-B-8-1-1-1-1-1, double cross DC2 (founders of double cross were FFZ1, CT 16658-5-2-2SR-2-3-6MP, IR 68, IR 02A127, eight parents population 8way (founders were SAGC-08, HHZ5-SAL9-Y3-Y1, BP1976B-2-3-7-TB-1-1, PR33282-B-8-1-1-1-1-1, FFZ1, CT 16658-5-2-2SR-2-3-6MP, IR 68, IR 02A127, DC12 (DC1+DC2 and rice multi-parent recombinant inbred line population RMPRIL (DC1+DC2+8way. A total of 21, 30, and 21 QTL were identified for Fe, Zn, and Al toxicity tolerance, respectively. For multi tolerance (MT as Fe, Zn, and Al tolerance-related traits, three genomic regions, MT1.1 (chr.1: 35.4–36.3 Mb, MT1.2 (chr.1: 35.4–36.3 Mb, and MT3.2 (chr.3: 35.4-36.2 Mb harbored QTL. The chromosomal regions MT2.1 (chr.2: 2.4–2.8 Mb, MT2.2 (chr.2: 24.5–25.8 Mb, MT4 (chr.4: 1.2 Mb Mb, MT8.1 (chr.8: 0.7–0.9 Mb, and MT8.2 (chr.8: 2.2–2.4 Mb harbored QTL for Fe and Zn tolerance, while MT2.3 (chr.2: 30.5–31.6 Mb, MT3.1 (chr.3: 12.5–12.8 Mb, and MT6 (chr.6: 2.0–3.0 Mb possessed QTL for Al and Zn tolerance. The chromosomal region MT9.1 (chr.9: 14.2–14.7 Mb possessed QTL for Fe and Al tolerance. A total of 11 QTL were detected across different MAGIC populations and 12 clustered regions were detected under different metal conditions, suggesting that these genomic regions might constitute valuable regions for further marker-assisted selection (MAS in breeding

Aging phenomena in Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} NTC ceramics

Energy Technology Data Exchange (ETDEWEB)

Shpotyuk, O.; Vakiv, M.; Mrooz, O. [Scientific Research Co. ' ' Carat' ' , Lviv (Ukraine); Hadzaman, I. [Scientific Research Co. ' ' Carat' ' , Lviv (Ukraine); Drohobych State Pedagogical Univ., Drohobych (Ukraine); Plewa, J.; Uphoff, H.; Altenburg, H. [Fachhochschule Muenster, Steinfurt (Germany)

2002-07-01

Aging effects in Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} NTC ceramics were studied for the first time by electrical and microstructural measurements. The increase in resistivity induced by aging tests at 125 and 170 C during 1000 h was observed. The changes of the electrical properties of the investigated NTC thermistors were explained, using the results of ceramics microstructural characterization, thermogravimetry, optical and electron microscopy techniques. (orig.)

Electrical and structural properties of La0.8Sr0.2Mn0.5Co0.5O3±δ films produced by pulsed laser deposition

DEFF Research Database (Denmark)

Pryds, Nini; Christensen, Bo Toftmann; Schou, Jørgen

2005-01-01

La0.8Sr0.2Mn0.5Co0.5O3 (LSMCO) films for the use as contact layers or protective coatings in solid oxide fuel cells (SOFC) have been deposited on glass substrates by pulsed laser deposition (PLD). PLD is an obvious technique for thin film production of complex oxides, because of the ability...

Size-dependent photocatalytic activity of La0.8Sr0.2MnO3 nanoparticles prepared by hydrothermal synthesis

Science.gov (United States)

Rahmani Afje, F.; Ehsani, M. H.

2018-04-01

Synthesize of La0.8Sr0.2MnO3 (LSMO) manganite were carried out in different particle sizes by hydrothermal method. Structural and optical properties of the prepared specimens were studied by x-ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), and UV–vis spectroscopy. The XRD study, coupled with the Rietveld refinement, exhibited rhombohedral structure with R-3C space group. Using the FT-IR and FESEM analyses, the perovskite structure of the samples with Nano-rod-like morphologies were inferred. Furthermore, the average sizes of 48.11, 70.99 and 111.45 nm were obtained for the ones sintered at 800, 900, and 1000 °C temperatures, respectively. The optical research showed that band gap energy is about 2.13 eV, being suitable in visible-light photocatalytic activity for water purification from dyes and toxic organic materials. The photo-degradation efficiency for decolorizing methyl orange solution (10 ppm) for various samples (100 ppm) were systematically probed and a strong relation is concluded between particle size and photocatalytic activity.

Near-infrared and upconversion properties of neodymium-doped RE0.8La0.2VO4 (RE = Y, Gd) single-crystal fibres grown by the laser-heated pedestal growth technique

International Nuclear Information System (INIS)

Camargo, A S S de; Nunes, L A O; Andreeta, M R B; Hernandes, A C

2002-01-01

Neodymium-doped Y 0.8 La 0.2 VO 4 and Gd 0.8 La 0.2 VO 4 single-crystal fibres were successfully grown by the laser-heated pedestal growth (LHPG) technique. The fibres were completely transparent and no dark inclusions were observed by optical microscopy. In the characterization process, microprobe Raman, optical absorption, fluorescence, lifetime, and gain-excited state absorption spectra were investigated in addition to upconversion measurements. The fibres' structural and spectroscopic properties are very similar to those of YVO 4 and GdVO 4 bulk laser crystals, with the advantageous characteristic of broadened spectral linewidths that facilitate the pumping of the 1064 nm emission by a diode laser. These fairly new crystal compositions, that can be grown in fast and economical processes, are potential candidates for use as compact laser-active media

A de novo 1.58 Mb deletion, including MAP2K6 and mapping 1.28 Mb upstream to SOX9, identified in a patient with Pierre Robin sequence and osteopenia with multiple fractures.

Science.gov (United States)

Smyk, Marta; Roeder, Elizabeth; Cheung, Sau Wai; Szafranski, Przemyslaw; Stankiewicz, Paweł

2015-08-01

Defects of long-range regulatory elements of dosage-sensitive genes represent an under-recognized mechanism underlying genetic diseases. Haploinsufficiency of SOX9, the gene essential for development of testes and differentiation of chondrocytes, results in campomelic dysplasia, a skeletal malformation syndrome often associated with sex reversal. Chromosomal rearrangements with breakpoints mapping up to 1.6 Mb up- and downstream to SOX9, and disrupting its distant cis-regulatory elements, have been described in patients with milder forms of campomelic dysplasia, Pierre Robin sequence, and sex reversal. We present an ∼1.58 Mb deletion mapping ∼1.28 Mb upstream to SOX9 that encompasses its putative long-range cis-regulatory element(s) and MAP2K6 in a patient with Pierre Robin sequence and osteopenia with multiple fractures. Low bone mass panel testing using massively parallel sequencing of 23 nuclear genes, including COL1A1 and COL1A2 was negative. Based on the previous mouse model of Map2k6, suggesting that Sox9 is likely a downstream target of the p38 MAPK pathway, and our previous chromosome conformation capture-on-chip (4C) data showing potential interactions between SOX9 promoter and MAP2K6, we hypothesize that deletion of MAP2K6 might have affected SOX9 expression and contributed to our patient's phenotype. © 2015 Wiley Periodicals, Inc.

Phase change and optical band gap behavior of Se0.8S0.2 chalcogenide glass films

International Nuclear Information System (INIS)

Abdel Rafea, M.; Farid, Huda

2009-01-01

Se 0.8 S 0.2 chalcogenide glass films have been prepared by thermal vacuum evaporation technique with thickness 583 nm. Annealing process at T ≥ 333 K crystallizes the films and nanostructured films are formed. The crystallite size was increased to 24 nm as the annealing temperature increased to 373 K. Orthorhombic crystalline system was identified for the annealed films. SEM micrographs show that films consist of two parallel surfaces and the thickness was determined by cross section imaging. The optical transmittance is characterized by interference patterns as a result of these two parallel surfaces, besides their average value at longer wavelength decreases as a result of annealing process. The band gap, E g is red shifted due to crystallization by annealing. As the phase of the films changes from amorphous to crystalline in the annealing temperature range 333-363 K, a non sharp change of the band gap (E g ) is observed. This change was explained by Brus's model of the energy gap confinement behavior of the nanostructured films. The optical refractive index increases suddenly when the system starts to be crystallized by annealing

Photoluminescence and scintillation properties of Ce-doped Sr2(Gd1-xLux)8(SiO4)6O2 (x = 0.1, 0.2, 0.4, 0.5, 0.6) crystals

Science.gov (United States)

Igashira, Takuya; Kawano, Naoki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

2018-05-01

Apatite crystals with chemical compositions of 0.5% Ce-doped Sr2(Gd1-xLux)8(SiO4)6O2 (x = 0.1, 0.2, 0.4, 0.5, 0.6) were synthesized by the Floating Zone method, and then we evaluated their photoluminescence (PL) and scintillation properties. All the Ce-doped samples exhibited PL and scintillation with an intense broad emission in 400-550 nm in which the origin was attributed to the 5d-4f transition of Ce3+, and the emission peak became broader with increasing the concentration of Lu3+. Both PL and scintillation decay time profiles were best-approximated by a sum of two exponential decay functions, and the origin of slower component was attributed to the 5d-4f transition of Ce3+. In the X-ray induced afterglow measurements, the Ce-doped Sr2(Gd0.4Lu0.6)8(SiO4)6O2 sample exhibited the lowest afterglow level. Furthermore, the Ce-doped Sr2(Gd0.5Lu0.5)8(SiO4)6O2 and Sr2(Gd0.4Lu0.6)8(SiO4)6O2 samples showed a clear full energy deposited peak under 5.5 MeV 241Am α-ray irradiation, and the estimated absolute scintillation light yields were around 290 and 1300 ph/5.5 MeV-α, respectively.

Clinician-scientist MB/PhD training in the UK: a nationwide survey of medical school policy.

Science.gov (United States)

Barnett-Vanes, Ashton; Ho, Guiyi; Cox, Timothy M

2015-12-30

This study surveyed all UK medical schools regarding their Bachelor of Medicine (MB), Doctor of Philosophy (PhD) (MB/PhD) training policy in order to map the current training landscape and to provide evidence for further research and policy development. Deans of all UK medical schools registered with the Medical Schools Council were invited to participate in this survey electronically. The number of medical schools that operate institutional MB/PhD programmes or permit self-directed student PhD intercalation. Medical school recruitment procedures and attitudes to policy guidance. 27 of 33 (81%) registered UK medical schools responded. Four (14%) offer an institutional MB/PhD programme. However, of those without institutional programmes, 17 (73%) permit study interruption and PhD intercalation: two do not (one of whom had discontinued their programme in 2013), three were unsure and one failed to answer the question. Regarding student eligibility, respondents cited high academic achievement in medical studies and a bachelor's or master's degree. Of the Medical schools without institutional MB/PhD programmes, 5 (21%) have intentions to establish a programme, 8 (34%) do not and 3 were unsure, seven did not answer. 19 medical schools (70%) considered national guidelines are needed for future MB/PhD programme development. We report the first national survey of MB/PhD training in the UK. Four medical schools have operational institutional MB/PhD programmes, with a further five intending to establish one. Most medical schools permit study interruption and PhD intercalation. The total number MB/PhD students yet to graduate from medical school could exceed 150, with 30 graduating per year. A majority of medical school respondents to this survey believe national guidelines are required for MB/PhD programme development and implementation. Further research should focus on the MB/PhD student experience. Discussion regarding local and national MB/PhD policies between medical

Experimental utilization of the IPEN/MB-01 reactor

International Nuclear Information System (INIS)

Bitelli, U. d'Utra; Santos, A. dos; Jerez, R.; Diniz, R.; Fanaro, L.C.C.B.; Abe, A.Y.; Moreira, J.M.L.; Fer, N.; Giada, M.R.; Fuga, R.

2003-01-01

This paper aims to show the experimental utilization of the IPEN/MB-01 nuclear reactor during the last fourteen years. The IPEN/MB-01 is a zero-power critical assembly specially designed to measure integral and differential reactor physics parameters to validate calculational methodologies and related nuclear data libraries. Experiments involving determination of spectral indices, critical mass, relative abundance of delayed neutrons, the inversion point of the isothermal reactivity coefficient and burnable poison are considered the most important experiments. Current experiments at IPEN/MB-01 reactor are also commented. (author)

X-ray scattering study of the temperature dependence of the structure of the high Tsub(c) superconductor Lasub(1.8)Srsub(0.2)CuO4

International Nuclear Information System (INIS)

Held, G.A.; Horn, P.M.; Tsuei, C.C.; LaPlaca, S.J.; Bednorz, J.G.; Mueller, K.A.

1987-01-01

We present data from powder scans of the High Tsub(c) (approx. 40 K) superconductor Lasub(1.8)Srsub(0.2)CuO 4 as a function of temperature from room temperature to 10 K. We observe a K 2 NiF 4 -type structure, with no evidence for a structural phase transition or anomalous changes in the lattice constants. For T > or approx. 190 K the values of the thermal expansion constants are not unusual for a metal oxide. (author)

Influence of ionic conductivity of the nano-particulate coating phase on oxygen surface exchange of La0.58Sr0.4Co0.2Fe0.8O3-δ

NARCIS (Netherlands)

Saher, S.; Naqash, S.; Boukamp, Bernard A.; Hu, Bobing; Xia, Changrong; Bouwmeester, Henricus J.M.

2017-01-01

The oxygen surface exchange kinetics of mixed-conducting perovskite La0.58Sr0.4Co0.2Fe0.8O3 d (LSCF) ceramics coated with a porous nano-particulate layer of either gadolinea (Gd2O3), ceria (CeO2) or 20 mol% Gd-doped ceria (GCO) was determined by electrical conductivity relaxation (ECR). The

High coronary calcium score and post-procedural CK-MB are noninvasive predictors of coronary stent restenosis

Directory of Open Access Journals (Sweden)

Lee JB

2017-02-01

Full Text Available Jae-Beom Lee,1 Yun-Seok Choi,2 Woo-Baek Chung,2 Ami Kwon,2 Chul-Soo Park,2 Man-Young Lee2 1Anyang Sam Hospital, 2Division of Cardiology, Department of Internal Medicine, Youido St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea Purpose: High coronary calcium score (CCS and post-procedural cardiac enzyme may be related with poor outcomes in patients with coronary stent implantation. Methods: A total of 1,072 patients (63.2% male, mean age: 61.7±10.3 years who underwent coronary multi-detect computed tomography at index procedure and follow-up coronary angiography (CAG after drug-eluting stent (DES were divided into two groups: those with and without target lesion revascularization (TLR; >50% reduction in luminal stent diameter or angina symptoms on follow-up CAG. The CCSs for predicting stent revascularization were elucidated. Results: There were no significant differences between the two groups with regard to risk factors. The initial CCS was significantly higher in the TLR group (1,102.4±743.7 vs 345.8±51.05, P=0.04. After adjustment of significant factors for TLR, only CCS and post-procedural creatine kinase MB form (CK-MB elevation were significant predictors of coronary artery TLR. Receiver operation curve revealed that >800 in CCS had 69% in sensitivity and 88% in specificity about predicting the TLR. Conclusion: High CCS with post-procedural CK-MB might be the useful predictors for TLR after DES implantation. Keywords: coronary restenosis, drug-eluting stents, calcium, creatine kinase

La(0.4)Ba(0.6)Fe(0.8)Zn(0.2)O(3-delta) as cathode in solid oxide fuel cells for simultaneous NO reduction and electricity generation.

Science.gov (United States)

Zhou, Renjie; Bu, Yunfei; Xu, Dandan; Zhong, Qin

2014-01-01

A perovskite-type oxide La(0.4)Ba(0.6)Fe(0.8)Zn(0.2)O(3-delta) (LBFZ) was investigated as the cathode material for simultaneous NO reduction and electricity generation in solid oxide fuel cells (SOFCs). The microstructure of LBFZ was demonstrated by X-ray diffraction and scanning electron microscopy. The results showed that a single cubic perovskite LBFZ was formed after calcined at 1100 degrees C. Meanwhile, the solid-state reaction between LBFZ and Ce(0.8)Sm(0.2)O(1.9) (SDC) at 900 degrees C was negligible. To measure the electrochemical properties, SOFC units were constructed with Sm(0.9)Sr(0.1)Cr(0.5)Fe(0.5)O3 as the anode, SDC as the electrolyte and LBFZ as the cathode. The maximum power density increased with the increasing NO concentration and temperature. The cell resistance is mainly due to the cathodic polarization resistance.

Gender differences in serum CK-MB mass levels in healthy Braziliansubjects

Directory of Open Access Journals (Sweden)

C.M.C. Strunz

2011-03-01

Full Text Available The creatine kinase-isoenzyme MB (CK-MB mass assay is one of the laboratory tests used for the diagnosis of myocardial infarction. It is recommended, however, that reference limits should take gender and race into account. In the present study, we analyzed the plasma CK-MB mass and troponin levels of 244 healthy volunteers without a personal history of coronary artery disease and with no chronic diseases, muscular trauma or hypothyroidism, and not taking statins. The tests were performed with commercial kits, CK-MB mass turbo kit and Troponin I turbo kit, using the Immulite 1000 analyzer from Siemens Healthcare Diagnostic. The values were separated according to gender and showed significant differences by the Mann-Whitney test. Mean (± SD CK-MB mass values were 2.55 ± 1.09 for women (N = 121; age = 41.20 ± 10.13 years and 3.49 ± 1.41 ng/mL for men (N = 123; age = 38.16 ± 11.12 years. Gender-specific reference values at the 99th percentile level, according to the Medicalc statistical software, were 5.40 ng/mL for women and 7.13 ng/mL for men. The influence of race was not considered because of the high miscegenation of the Brazilian population. The CK-MB values obtained were higher than the 5.10 mg/mL proposed by the manufacturer of the laboratory kit. Therefore, decision limits should be related to population and gender in order to improve the specificity of this diagnostic tool, avoiding misclassification of patients

Processing of La(1.8)Sr(0.2)CuO4 and YBa2Cu3O7 superconducting thin films by dual-ion-beam sputtering

Science.gov (United States)

Madakson, P.; Cuomo, J. J.; Yee, D. S.; Roy, R. A.; Scilla, G.

1988-03-01

High-quality La(1.8)Sr(0.2)CuO4 and YBa2Cu3O7 superconducting thin films, with zero resistance at 88 K, have been made by dual-ion-beam sputtering of metal and oxide targets at elevated temperatures. The films are about 1.0 micron thick and are single phase after annealing. The substrates investigated are Nd-YAP, MgO, SrF2, Si, CaF2, ZrO2-(9 pct)Y2O3, BaF2, Al2O3, and SrTiO3. Characterization of the films was carried out using Rutherford backscattering spectroscopy, resistivity measurements, TEM, X-ray diffraction, and SIMS. Substrate/film interaction was observed in every case. This generally involves diffusion of the substrate into the film, which is accompanied by, for example, the replacement of Ba by Sr in the YBa2Cu2O7 structure, in the case of SrTiO3 substrate. The best substrates were those that did not significantly diffuse into the film and which did not react chemically with the film.

Structural, magnetic and optical characterization of Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nano particles prepared by co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Kannan, Y.B., E-mail: ybkans@gmail.com [Department of Physics, Arumugam Pillai Seethai Ammal College, Tiruppattur 630211 (India); Saravanan, R. [Research Centre & PG Department of Physics, The Madura College, Madurai 625011 (India); Srinivasan, N. [Research Centre & PG Department of Physics, Thiagarajar College, Madurai 625009 (India); Praveena, K. [School of Physics, Univeristy of Hyderabad, Hyderabad 500046 (India); Sadhana, K. [Material Research Center, Indian Institute of Science, Bangalore 560012 (India)

2016-12-01

Bond strength values, between tetrahedral sites and octahedral sites atoms in the unit cell, are evaluated using maximum entropy method (MEM) for the Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} nano ferrite particles, prepared by co-precipitation method and sintered at 900 °C. The spinel structure is confirmed from the XRD analysis done using the Rietveld method. Substitution of zinc ion causes increase in lattice parameter value. Thermal behavior, morphology, magnetic properties and optical band gap energy values of the sample are determined by using thermogravimetric analysis and differential thermal analysis, scanning electron microscope, vibrating sample magnetometer and UV–VIS–NIR techniques respectively. Low value of saturation magnetization is attributed to the disorder in cation distribution.

Near-UV and blue wavelength excitable Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} high efficiency red phosphors

Energy Technology Data Exchange (ETDEWEB)

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

2015-05-15

Red phosphors with narrow emission around 615 nm (with FWHM~5–10 nm) having chemical compositions of A{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} (A=Mg, Sr) have been found to exhibit the highest luminescence amongst the molybdate–tungstate family when excited by sources in the 380–420 nm wavelength range. Thus they are most suitable for enhancing color rendering index and lowering color temperature in phosphor converted white LEDs (pc-WLEDs) with near-UV/blue LED excitation sources. The excitation band edge in the near UV/blue wavelength in the reported phosphor has been attributed to the coordination environment of the transition metal ion (Mo{sup 6+}, W{sup 6+}) and host crystal structure. Furthermore the quantum efficiency of the phosphors has been enhanced by adjusting activator concentration, suitable compositional alloying using substitutional alkaline earth metal cations and charge compensation mechanisms. - Graphical abstract: The charge transfer excitation of orthorhombic Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} is significantly higher than tetragonal CaMoO{sub 4}: Eu{sup 3+} phosphors making Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} prime candidates for fabrication of warm white phosphor-converted LEDs. - Highlights: • LED excitable Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} phosphors were synthesized. • These phosphors are 10 times more intense than CaMoO{sub 4}: Eu{sup 3+} red phosphors. • Their intensity and efficiency were enhanced by materials optimization techniques. • Such techniques include compositional alloying, charge compensation, etc.

CREATINE PHOSPHOKINASE ISOENZYME-MB MASS (CK-MB MASS AND TROPONIN I (cTnI IN DOGS (Canis familiaris

Directory of Open Access Journals (Sweden)

Millena Vidal Freitas

2015-07-01

Full Text Available Cardiac markers, especially CK-MB mass and cTnI, have an essential role in both human and veterinary clinical and surgical cardiology, allowing a more precise and accurate diagnosis in myocardial lesions. The goal of this work was to measure these cardiac markers in veterinary medicine, improve their use and provide information about these laboratory methods that allow non-invasive health monitoring of the myocardial cell. Parameters quantification was obtained from sera of healthy dogs examined during routine procedures at the Small Animal Veterinary Hospital of Universidade Estadual do Norte Fluminense Darcy Ribeiro. The human chemiluminescence essay turbo kit (IMMULITE Turbo, Siemens ® test proved to be effective in canine species for both CK-MB mass and cTnI. In addition, the values found for CK-MB will significantly contribute to clinical routine or experimental work with dogs.

Impedance spectroscopy and ferromagnetic properties of Bi{sub 0.8}Gd{sub 0.2}FeO{sub 3} multiferroics

Energy Technology Data Exchange (ETDEWEB)

Tian, Yahui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Xue, Fei [Center of Collaboration and Innovation, Jiangxi University of Technology, Nanchang, Jiangxi 330098 (China); Fu, Qiuyun, E-mail: fuqy@mail.hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhou, Dongxiang; Hu, Yunxiang; Zhou, Ling; Zheng, Zhiping; Xin, Zengnian [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)

2017-08-01

Highlights: • BGFO ceramics exhibited high density, strong ferroelectricity, and good magnetism. • BGFO ceramics exhibited typical relaxor behavior. • There are different conductivity mechanisms at different temperatures for BGFO. - Abstract: Multiferroic Bi{sub 0.8}Gd{sub 0.2}FeO{sub 3} (BGFO) ceramics were prepared by a rapid-liquid phase sintering process. BGFO ceramics can be sintered at a sintering temperature range of 875 °C–940 °C and shown a pure orthorhombic (space group, Pnma) structure. The crystal symmetry and lattice parameters were determined from the Rietveld analysis for the experimental data. BGFO ceramics sintered at 900 °C exhibited high theoretical relative density (∼98%), strong ferroelectricity and good magnetism. BGFO ceramics exhibited the similar dielectric relaxation properties to the typical relaxor ferroelectrics. The role of oxygen vacancies at high temperature in dielectric and ac conductivity behavior was also discussed. The diffusing of structure defects between the grain and grain boundary was established using Impedance Spectroscopy (IS).

Sex differences in the MB49 syngeneic, murine model of bladder cancer.

Science.gov (United States)

White-Gilbertson, Shai; Davis, Megan; Voelkel-Johnson, Christina; Kasman, Laura M

The MB49 syngeneic, murine model of bladder cancer has been widely used for more than 35 years. In humans, bladder cancer is one third as prevalent in women as in men, with a trend toward lower prevalence in parous compared to nulliparous women. Our objective was to determine if the MB49 bladder cancer model reproduces the sex differences observed in humans, and to determine its sensitivity to testosterone and the pregnancy hormone, human chorionic gonadotropin (hCG). Male and female C57BL/6 mice were implanted with MB49 murine bladder cancer cells, and observed for tumor growth. MB49 dose responses to hCG and dihydrotestosterone were determined in vitro . MB49 tumor growth was significantly greater in male mice than female mice. Pregnancy did not affect MB49 tumor growth in female mice. MB49 cells did not proliferate in response to hCG in vitro and the functional receptor for gonadotropins was absent. Dihydrotestosterone strongly stimulated growth of MB49 cells in vitro . The MB49 murine model of bladder cancer reproduced some aspects of the sex differences observed in humans. Our results suggest that testosterone may stimulate MB49 cell proliferation, which may explain the more rapid MB49 tumor growth observed in male mice.

Identification and characterisation of novel associations in the CASP8/ALS2CR12 region on chromosome 2 with breast cancer risk

OpenAIRE

Lin, Wei-Yu; Camp, Nicola J; Ghoussaini, Maya; Beesley, Jonathan; Michailidou, Kyriaki; Hopper, John L; Apicella, Carmel; Stone, Jennifer; Schmidt, Marjanka K; Broeks, Annegien; Van't, Veer Laura J; Rutgers, Emiel J Th; Muir, Kenneth; Lophatananon, Artitaya; Stewart-Brown, Sarah

2014-01-01

Previous studies have suggested that polymorphisms in CASP8 on chromosome 2 are associated with breast cancer risk. To clarify the role of CASP8 in breast cancer susceptibility we carried out dense genotyping of this region in the Breast Cancer Association Consortium (BCAC). Single nucleotide polymorphisms (SNPs) spanning a 1Mb region around CASP8 were genotyped in 46,450 breast cancer cases and 42,600 controls of European origin from 41 studies participating in the BCAC as part of a custom g...

Physicochemical and thermodynamic investigation of hydrogen absorption and desorption in LaNi3.8Al1.0Mn0.2 using the statistical physics modeling

Science.gov (United States)

Bouaziz, Nadia; Ben Manaa, Marwa; Ben Lamine, Abdelmottaleb

2018-06-01

In the present work, experimental absorption and desorption isotherms of hydrogen in LaNi3.8Al1.0Mn0.2 metal at two temperatures (T = 433 K, 453 K) have been fitted using a monolayer model with two energies treated by statistical physics formalism by means of the grand canonical ensemble. Six parameters of the model are adjusted, namely the numbers of hydrogen atoms per site nα and nβ, the receptor site densities Nmα and Nmβ, and the energetic parameters Pα and Pβ. The behaviors of these parameters are discussed in relationship with temperature of absorption/desorption process. Then, a dynamic investigation of the simultaneous evolution with pressure of the two α and β phases in the absorption and desorption phenomena using the adjustment parameters. Thanks to the energetic parameters, we calculated the sorption energies which are typically ranged between 276.107 and 310.711 kJ/mol for absorption process and between 277.01 and 310.9 kJ/mol for desorption process comparable to usual chemical bond energies. The calculated thermodynamic parameters such as entropy, Gibbs free energy and internal energy from experimental data showed that the absorption/desorption of hydrogen in LaNi3.8Al1.0Mn0.2 alloy was feasible, spontaneous and exothermic in nature.

Synthesis and structural investigation of new Co1-xNixTeO4 (x = 0, 0.2, 0.5, 0.8 and 1) compounds

Science.gov (United States)

Patel, Akhilesh K.; Singh, Harishchandra; Suresh, K. G.

2018-05-01

The new polycrystalline compounds Co1-xNixTeO4 (x = 0, 0.2, 0.5, 0.8 and 1) were prepared by sol-gel method and their structural properties have been studied. Structural investigation through Rietveld method shows monoclinic structure with space group P21/c for all compounds. All compounds polyhedral structure found to be in octahedral form with cations (M) at the center and six oxygen atoms at corner of octahedral structure. The lattice parameters variation with Ni substitution are found to be decreasing with Ni substitution.

Nanoblast synthesis and consolidation of (La0.8Sr0.2)(Ga0.9Mg0.1)O(3-delta) under Spark plasma sintering conditions.

Science.gov (United States)

Vasylkiv, Oleg; Borodianska, Hanna; Badica, Petre; Zhen, Yongda; Tok, Alfred

2009-01-01

Four-cation nanograined strontium and magnesium doped lanthanum gallate (La0.8Sr0.2) (Ga0.9Mg0.1)O(3-delta) (LSGM) and its composite with 2 wt% of ceria (LSGM-Ce) were prepared. Morphologically homogeneous nanoreactors, i.e., complex intermediate metastable aggregates of desired composition were assembled by spray atomization technique, and subsequently loaded with nanoparticles of highly energetic C3H6N6O6. Rapid nanoblast calcination technique was applied and the final composition was synthesized within the preliminary localized volumes of each single nanoreactor on the first step of spark plasma treatment. Subsequent SPS consolidations of nanostructured extremely active LSGM and LSGM-Ce powders were achieved by rapid treatment under pressures of 90-110 MPa. This technique provided the heredity of the final structure of nanosize multimetal oxide, allowed the prevention of the uncontrolled agglomeration during multicomponent aggregates assembling, subsequent nanoblast calcination, and final ultra-rapid low-temperature SPS consolidation of nanostructured ceramics. LaSrGaMgCeO(3-delta) nanocrystalline powder consisting of approximately 11 nm crystallites was consolidated to LSGM-Ce nanoceramic with average grain size of approximately 14 nm by low-temperature SPS at 1250 degrees C. Our preliminary results indicate that nanostructured samples of (La0.8Sr0.2)(Ga0.9Mg0.1)O(3-delta) with 2 wt% of ceria composed of approximataley 14 nm grains can exhibit giant magnetoresistive effect in contrast to the usual paramagnetic properties measured on the samples with larger grain size.

Influence of boron vacancies on phase stability, bonding and structure of MB2 (M  =  Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W) with AlB2 type structure

International Nuclear Information System (INIS)

Dahlqvist, Martin; Rosen, Johanna; Jansson, Ulf

2015-01-01

Transition metal diborides in hexagonal AlB 2 type structure typically form stable MB 2 phases for group IV elements (M  =  Ti, Zr, Hf). For group V (M  =  V, Nb, Ta) and group VI (M  =  Cr, Mo, W) the stability is reduced and an alternative hexagonal rhombohedral MB 2 structure becomes more stable. In this work we investigate the effect of vacancies on the B-site in hexagonal MB 2 and its influence on the phase stability and the structure for TiB 2 , ZrB 2 , HfB 2 , VB 2 , NbB 2 , TaB 2 , CrB 2 , MoB 2 , and WB 2 using first-principles calculations. Selected phases are also analyzed with respect to electronic and bonding properties. We identify trends showing that MB 2 with M from group V and IV are stabilized when introducing B-vacancies, consistent with a decrease in the number of states at the Fermi level and by strengthening of the B–M interaction. The stabilization upon vacancy formation also increases when going from M in period 4 to period 6. For TiB 2 , ZrB 2 , and HfB 2 , introduction of B-vacancies have a destabilizing effect due to occupation of B–B antibonding orbitals close to the Fermi level and an increase in states at the Fermi level. (paper)

A {mu}SR study of the magnetoresistive ruthenocuprates RuSr{sub 2}Nd{sub 1.8-x}Y {sub 0.2}Ce{sub x}Cu{sub 2}O{sub 10-{delta}} (x = 0.95 and 0.80)

Energy Technology Data Exchange (ETDEWEB)

Mclaughlin, A C [Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE (United Kingdom); Attfield, J P [Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, King' s Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom); Van Duijn, J [Instituto de Investigacion en EnergIas Renovables, Universidad de Castilla la Mancha, Albacete, E02006 (Spain); Hillier, A D, E-mail: a.c.mclaughlin@abdn.ac.uk [ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

2011-09-14

Zero field muon spin relaxation (ZF-{mu}SR) has been used to study the magnetic properties of the underdoped giant magnetoresistive ruthenocuprates RuSr{sub 2}Nd{sub 1.8-x}Y {sub 0.2}Ce{sub x}Cu{sub 2}O{sub 10-{delta}} (x = 0.95, 0.80). The magnetoresistance (MR) is defined so that MR = (({rho}{sub H}-{rho}{sub 0})/{rho}{sub 0}) and the giant magnetoresistive ruthenocuprates RuSr{sub 2}Nd{sub 1.8-x}Y {sub 0.2}Ce{sub x}Cu{sub 2}O{sub 10-{delta}} exhibit a large reduction in electronic resistivity upon application of a magnetic field. The ZF-{mu}SR results show a gradual loss of initial asymmetry A{sub 0} at the ruthenium spin transition temperature, T{sub Ru}. At the same time the electronic relaxation rate, {lambda}, shows a gradual increase with decreasing temperature below T{sub Ru}. These results have been interpreted as evidence for Cu spin cluster formation below T{sub Ru}. These magnetically ordered clusters grow as the temperature is decreased thus causing the initial asymmetry to decrease slowly. Giant magnetoresistance is observed over a wide temperature range in the materials studied and the magnitude increases as the temperature is reduced from T{sub Ru} to 4 K which suggests a relation between Cu spin cluster size and |-MR|. (paper)

Part II. Large scale applications of Ni{sub x}Mn{sub 0.8-x}Mg{sub 0.2}Fe{sub 2}O{sub 4}; 0.1 {<=} x {<=} 0.35 using laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Ahmed, M.A., E-mail: moala1947@yahoo.com [Materials Science. Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Bishay, Samiha T. [Department of Physics, Faculty of Girls for Art, Science and Education, Ain Shams University, Cairo (Egypt); El-dek, S.I.; Omar, G. [Materials Science. Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

2011-07-28

Highlights: >X-ray diffractograms of Ni{sub x}Mn{sub 0.8-x}Mg{sub 0.2}Fe{sub 2}O{sub 4} samples before and after laser irradiation are characteristic of cubic spinel structure with better crystallinity after irradiation. > The crystal size of the ferrite increases after laser irradiation. > The main conduction mechanism in the investigated system is the correlated barrier hopping and it is the same before and laser irradiation. > The conductivity decreases after laser irradiation. - Abstract: Ni{sub x}Mn{sub 0.8-x}Mg{sub 0.2}Fe{sub 2}O{sub 4}; 0.1 {<=} x {<=} 0.35 was prepared by standard ceramic technique at sintering temperature 1200 deg. C using heating / cooling rate 4 deg. C/min. The samples were irradiated by Nd YAG pulsed laser with energy of the pulse 250 mJ. X-ray diffractograms reveal cubic spinel structure for all the samples before and after laser irradiation. After laser irradiation, better crystallinity was obtained in a form of an increase in the calculated crystal size. This increase was discussed as due to the change in the valence of some ions like Fe{sup 3+}, Ni{sup 2+} and Mn{sup 2+}. The conductivity of all the investigated samples decreases after laser irradiation and becomes temperature independent for a wider range than that before irradiation. This was ascribed to electron rearrangement after laser irradiation. Accordingly, these ferrites are recommended to be useful in electronic devices.

Electronic conductivity of Ce(0.9)Gd(0.1)O(1.95-δ) and Ce(0.8)Pr(0.2)O(2-δ): Hebb-Wagner polarisation in the case of redox active dopants and interference

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2011-01-01

of the steady state I-V curve from the standard Hebb-Wagner equation was observed for the case of Ce(0.8)Pr(0.2)O(2-δ). It is shown that the I-V curve can be successfully reproduced when the presence of the redox active dopant, Pr(3+)/Pr(4+), is taken into account, whereas even better agreement can be reached...

A study of (Ba0.5Sr0.5)1-xSm xCo0.8Fe0.2O3-δ as a cathode material for IT-SOFCs

International Nuclear Information System (INIS)

Li Shuyan; Lue Zhe; Wei Bo; Huang Xiqiang; Miao Jipeng; Cao Gang; Zhu Ruibin; Su Wenhui

2006-01-01

(Ba 0.5 Sr 0.5 ) 1-x Sm x Co 0.8 Fe 0.2 O 3-δ (BSSCF; x = 0.05-0.15) compounds were synthesized with EDTA-Pechini method and characterized by powder X-ray diffraction (XRD), electrical conductivity and thermal expansion coefficient (TEC) measurements, as well as the electrochemical impedance spectra measurement. According to the XRD results, the main phase of the material belongs to the cubic perovskite-type, and the lattice contracting with the increasing contents of Sm 3+ . The TEC of the compounds is 19.1-20.3 x 10 -6 K -1 from 30 to 800 deg. C, which close to the values of Co-based materials, such as Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF). And the conductivity of BSSCF is higher than that of BSCF; e.g., about 212% higher at 500 deg. C for the x = 0.15 compound. Electrochemical impedance spectra at intermediate temperature revealed the better electrochemical performance of BSSCF than BSCF; e.g., the total resistance values of BSSCF electrode is 2.98 Ω cm 2 at 500 deg. C, nearly 50% lower than that of BSCF

Chemically stable perovskites as cathode materials for solid oxide fuel cells: La-doped Ba0.5Sr0.5Co0.8Fe0.2O(3-δ).

Science.gov (United States)

Kim, Junyoung; Choi, Sihyuk; Jun, Areum; Jeong, Hu Young; Shin, Jeeyoung; Kim, Guntae

2014-06-01

Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) (BSCF) has won tremendous attention as a cathode material for intermediate-temperature solid-oxide fuel cells (IT-SOFC) on the basis of its fast oxygen-ion transport properties. Nevertheless, wide application of BSCF is impeded by its phase instabilities at intermediate temperature. Here we report on a chemically stable SOFC cathode material, La0.5Ba0.25Sr0.25Co0.8Fe0.2O(3-δ) (LBSCF), prepared by strategic approaches using the Goldschmidt tolerance factor. The tolerance factors of LBSCF and BSCF indicate that the structure of the former has a smaller deformation of cubic symmetry than that of the latter. The electrical property and electrochemical performance of LBSCF are improved compared with those of BSCF. LBSCF also shows excellent chemical stability under air, a CO2-containg atmosphere, and low oxygen partial pressure while BSCF decomposed under the same conditions. Together with this excellent stability, LBSCF shows a power density of 0.81 W cm(-2) after 100 h, whereas 25 % degradation for BSCF is observed after 100 h. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of chemical treatment on the electrochemical properties of Li1.2NixMn0.8-xO2 (x = 0.2 and 0.25) in lithium-ion batteries

Science.gov (United States)

Konishi, Hiroaki; Hirano, Tatsumi; Takamatsu, Daiko; Gunji, Akira; Feng, Xiaoliang; Furutsuki, Sho; Okumura, Takefumi; Terada, Shohei

2018-02-01

The effect of chemical treatment using (NH4)2SO4 on the electrochemical properties of Li1.2Ni0.2Mn0.6O2 and Li1.2Ni0.25Mn0.55O2 was investigated. The treatment was effective in improving the Coulombic efficiency and discharge capacity of a Li1.2Ni0.2Mn0.6O2 cathode, but treatment with too much (NH4)2SO4 degraded the cathode's electrochemical performance. The effect of (NH4)2SO4 treatment on the charge-discharge reaction mechanism of Li1.2Ni0.2Mn0.6O2 was investigated by evaluating reaction potential, particle configuration, and oxidation state of transition metal. The experimental results indicated that the changes in the electrochemical performance of the treated cathodes were attributed to the changes in the surface state and of the element contributing to the redox reaction. Treatment with an appropriate amount of (NH4)2SO4 also improved the electrochemical performance of the high-nickel-content lithium-rich layer-structured cathode material Li1.2Ni0.25Mn0.55O2.

Gd0.6Sr0.4Fe0.8Co0.2O3-δ: A novel type of SOFC cathode

DEFF Research Database (Denmark)

Kammer Hansen, Kent; Søgaard, Martin; Mogensen, Mogens Bjerg

2007-01-01

The fabrication and electrochemical activity of a type of solid oxide fuel cell (SOFC) cathode is described in this paper. In search of new cathodes a Gd0.6Sr0.4Fe0.8Co0.2O3-delta compound was synthesized using the glycine-nitrate method. It turned out that this was a two-phase compound consisting...... of two perovskite phases, a cubic and an orthorhombic phase, as shown by Rietveld refinements. These two phases were synthesized and a cone-shaped electrode study was undertaken. It was shown that the composite cathode had an electrochemical activity superior to that of the two single-phase perovskites......, indicating that the unique microstructure of this type of cathode is essential for achieving high electrochemical activity toward the reduction of oxygen in a SOFC....

Monoclinic MB phase and phase instability in [110] field cooled Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 single crystals

Science.gov (United States)

Yao, Jianjun; Cao, Hu; Ge, Wenwei; Li, Jiefang; Viehland, D.

2009-08-01

We report the finding of a monoclinic MB phase in Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 single crystals. High precision x-ray diffraction investigations of [110] field cooled crystals have shown a transformation sequence of cubic(C)→tetragonal(T)→orthorhombic(O)→monoclinic(MB), which is different from that previously reported [A.-E. Renault et al., J. Appl. Phys. 97, 044105 (2005)]. Beginning in the zero-field-cooled condition at 383 K, a rhombohedral (R)→MB→O sequence was observed with increasing field. Coexisting MB and O phases were then found upon removal of field, which fully transformed to MB on cooling to room temperature.

A 5.2/5.8 GHz Dual Band On-Off Keying Transmitter Design for Bio-Signal Transmission

Science.gov (United States)

Wu, Chang-Hsi; You, Hong-Cheng; Huang, Shun-Zhao

2018-02-01

An architecture of 5.2/5.8-GHz dual-band on-off keying (DBOOK) modulated transmitter is designed in a 0.18-μm CMOS technology. The proposed DBOOK transmitter is used in the biosignal transmission system with high power efficiency and small area. To reduce power consumption and enhance output swing, two pairs of center-tapped transformers are used as both LC tank and source grounding choke for the designed voltage controlled oscillator (VCO). Switching capacitances are used to achieve dual band operations, and a complemented power combiner is used to merge the differential output power of VCO to a single-ended output. Besides, the linearizer circuits are used in the proposed power amplifier with wideband output matching to improve the linearity both at 5.2/5.8-GHz bands. The designed DBOOK transmitter is implemented by dividing it into two chips. One chip implements the dual-band switching VCO and power combiner, and the other chip implements a linear power amplifier including dual-band operation. The first chip drives an output power of 2.2mW with consuming power of 5.13 mW from 1.1 V supply voltage. With the chip size including pad of 0.61 × 0.91 m2, the measured data rate and transmission efficiency attained are 100 Mb/s and 51 pJ/bit, respectively. The second chip, for power enhanced mode, exhibits P1 dB of -9 dBm, IIP3 of 1 dBm, the output power 1 dB compression point of 12.42 dBm, OIP3 of about 21 dBm, maximum output power of 17.02/16.18 dBm, and power added efficiency of 17.13/16.95% for 5.2/ 5.8 GHz. The chip size including pads is 0:693 × 1:084mm2.

Anisotropic bonded Sm{sub 2.3}Fe{sub 16.8}Zr{sub 0.2}N{sub y} magnets prepared by milling of as cast material

Energy Technology Data Exchange (ETDEWEB)

Gebel, B.; Kubis, M.; Roessler, U.K.; Mueller, K.H. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe

2001-07-01

As cast Sm{sub 2.3}Fe{sub 16.8}Zr{sub 0.2} material was milled for 100 min {<=} t {<=} 900 min. After annealing at 800 C for 1 h and subsequent nitrogenation, the samples were cold compacted in a magnetic field and resin bonded. The coercivity {mu}{sub 0J}H{sub C} of the samples increased from 0.59 T (t = 100 min) to 2.18 T (t = 900 min). On the other hand, the remanence along the texture axis decreased monotonically with increasing milling time due to the decrease of the degree of texture of the aligned powders. Prolonged milling leads finally to the formation of a soft magnetic phase as indicated by a shoulder in the demagnetization curve for t > 600 min. The highest energy product (BH){sub max} of 50 kJm{sup -3} (136 kJm{sup -3} for the theoretical density of 7.7 gcm{sup -3}) was obtained for an intermediate milling time of 400 min. Zn bonding of the powders resulted in magnets with lower energy products but improved coercivities. (orig.)

Hydrogen diffusion in the storage compound Ti sub(0.8) Zr sub(0.2)CrMnH3 studied by neutron scattering

International Nuclear Information System (INIS)

Pugliesi, R.

1983-01-01

The hydrogen diffusion in the storage material Ti sub(0.8) Zr sub(0.2)CrMnH 3 has been studied in the temperature range of 260 to 360K, by means of the quasi-elastic neutron scattering technique. The experimental measurements have been performed using a high resolution backscattering spectrometer. The half widths at half maximum of the quasi-elastic line have been determined for momentum transfers in the range 0.24 to 1.85 A -1 . The data, corrected for multiple scattering effect, have been analysed in term of simple diffusion and jump diffusion models. From the diffusion coefficients determined at different temperatures, the following Arrhenius equation was obtained: D= (3+-1) x 10 -8 m 2 /s exp [-(220+-20 meV/kT] yielding a diffusion coefficient at room temperature of 6.0 x 10 -12 m 2 /s. This comparatively fast hydrogen diffusion is not the rate determining step in the absorption and desorption kinetics. The results at large momentum transfers show evidence for the existence of more than one component in the quasi-elastic spectra. This fact has been explained considering the diffusion governed by the existence of energetically different interstitial sites and by blocking effects due to the high hydrogen concentration. (Author) [pt

Absence of confinement in (SrTiO3)/( SrTi0.8Nb0.2O3 ) superlattices

Science.gov (United States)

Bouzerar, G.; Thébaud, S.; Bouzerar, R.; Pailhès, S.; Adessi, Ch.

2018-03-01

The reduction of dimensionality is considered an efficient pathway to boost the performances of thermoelectric materials. Quantum confinement of the carriers is expected to induce large Seebeck coefficients (S ) and it also suppresses the thermal conductivity by increasing the phonon scattering processes. However, quantum confinement in superlattices is not always easy to achieve and needs to be carefully validated. In the past decade, large values of S have been measured in (SrTiO3)/(SrTi0.8Nb0.2O3 ) superlattices [H. Ohta et al., Nat. Mater. 6, 129 (2007), 10.1038/nmat1821; Y. Mune et al., Appl. Phys. Lett. 91, 192105 (2007), 10.1063/1.2809364]. In the δ -doped compound, the reported S was almost six times larger than that of the bulk material. This huge increase has been attributed to the two-dimensional carrier confinement in the doped regions. Here, we demonstrate that the experimental data are well explained quantitatively assuming delocalized electrons in both in-plane and growth directions. Moreover, we rule out the confined electron hypothesis whose signature would be the suppression of the Seebeck coefficient. This strongly suggests that the presupposed confinement picture in these superlattices is unlikely.

Stability and oxygen transport property of La0.8Sr0.2Cr0.5Fe0.5O3 -δ

DEFF Research Database (Denmark)

He, Wei; Huang, Hua; Chen, Ming

2014-01-01

vacancies in the lattice. LSCrF powder exposed to flowing concentrated hydrogen for 30 h was found to decompose partially. The decomposition oxygen partial pressure of LSCrF at 950 °C was estimated to be 6.3 × 10- 28 atm from thermodynamic calculations. The stability of LSCrF under an oxygen chemical......The stability of La0.8Sr0.2Cr0.5Fe 0.5O3 -δ (LSCrF) in reducing atmosphere was investigated by examining the extent of its reaction with hydrogen at elevated temperature. LSCrF powder exposed to diluted hydrogen was found to loss a weight of only ~ 0.5%, corresponding to the formation of oxygen...... potential gradient was also examined by exposing a disk-shaped dense sample to air at one side and to reducing atmosphere (CO) at the other side at elevated temperatures. A thin, porous layer was found to form on the CO side surface. An oxygen permeation flux of 2.5 × 10- 7 mol cm- 2 s- 1 was observed...

Two-site immunoradiometric assay for the MB isoenzyme of creatine kinase

Energy Technology Data Exchange (ETDEWEB)

Willson, V J.C.; Jones, H M; Thompson, R J [Cambridge Univ. (UK). Clinical School

1981-06-18

A two-site immunoradiometric assay for myocardial creatine kinase MB isoenzyme is described. The method utilizes immobilized anti-human creatine kinase BB antibodies and /sup 125/I-labelled anti-human creatine kinase MM antibodies and can specifically detect creatine kinase MB in the presence of approximately 1000-fold excess of creatine kinase MM or BB. Native kinase MB prepared from human heart and creatine kinase MB prepared by hybridisation of purified human creatine kinase MM and creatine kinase BB appeared to react identically in the assay. Serum estimations on patients with suspected myocardial infarction correlated with the presence of MB band on electrophoresis but preliminary results suggest that the two-site immunoradiometric assay may be more sensitive.

Electrocaloric effect and freezing temperature in (Pb0.8Ba0.2[(Zn1∕3Nb2∕30.7Ti0.3]O3 relaxor ferroelectric ceramic

Directory of Open Access Journals (Sweden)

A. Peláiz-Barranco

2016-09-01

Full Text Available The electrocaloric effect (ECE is studied in (Pb0.8Ba0.2[(Zn1∕3Nb2∕30.7Ti0.3]O3 relaxor ferroelectric ceramic by using an “indirect method”. The electric dependence for the polarization (hysteresis loops has been obtained for several temperatures showing typical relaxor characteristics. The temperature change ΔT, which is associated with the ECE, is calculated by using the temperature dependence for the polarization. A maximum value for ΔT is observed for temperatures close above the freezing temperature, showing an indirect evidence of that critical temperature. The results are discussed considering the contribution of the polar nanoregions to the polarization.

MB109 as bioactive human bone morphogenetic protein-9 refolded and purified from E. coli inclusion bodies

Science.gov (United States)

2014-01-01

Background The development of chemical refolding of transforming growth factor-beta (TGF-β) superfamily ligands has been instrumental to produce the recombinant proteins for biochemical studies and exploring the potential of protein therapeutics. The osteogenic human bone morphogenetic protein-2 (hBMP-2) and its Drosophila DPP homolog were the early successful cases of refolding into functional form. Despite the similarity in their three dimensional structure and amino acid sequences, several other TGF-β superfamily ligands could not be refolded readily by the same methods. Results Here, we report a comprehensive study on the variables of a rapid-dilution refolding method, including the concentrations of protein, salt, detergent and redox agents, pH, refolding duration and the presence of aggregation suppressors and host-cell contaminants, in order to identify the optimal condition to refold human BMP-9 (hBMP-9). To produce a recombinant form of hBMP-9 in E. coli cells, a synthetic codon-optimized gene was designed to encode the mature domain of hBMP-9 (Ser320 – Arg429) directly behind the first methionine, which we herein referred to as MB109. An effective purification scheme was also developed to purify the refolded MB109 to homogeneity with a final yield of 7.8 mg from 100 mg of chromatography-purified inclusion bodies as a starting material. The chemically refolded MB109 binds to ALK1, ActRIIb and BMPRII receptors with relatively high affinity as compared to other Type I and Type II receptors based on surface plasmon resonance analysis. Smad1-dependent luciferase assay in C2C12 cells shows that the MB109 has an EC50 of 0.61 ng/mL (25 pM), which is nearly the same as hBMP-9. Conclusion MB109 is prone to be refolded as non-functional dimer and higher order multimers in most of the conditions tested, but bioactive MB109 dimer can be refolded with high efficiency in a narrow window, which is strongly dependent on the pH, refolding duration, the presence of

Effects of oxygen annealing on the physical properties and surface microstructures of La0.8Ba0.2MnO3 films

International Nuclear Information System (INIS)

Murugavel, P; Lee, J H; Lee, K-B; Park, J H; Chung, J-S; Yoon, J-G; Noh, T W

2002-01-01

We have investigated the effects of oxygen annealing on the transport properties and surface microstructures of epitaxial La 0.8 Ba 0.2 MnO 3 (LBMO) films deposited on SrTiO 3 substrate at different oxygen pressures using the pulsed laser deposition technique. The thickness dependence of the transport properties was strongly affected by the oxygen pressure during the deposition and the oxygen annealing temperature. Oxygen stoichiometry, in addition to the substrate-induced strain, was found to be a very important factor in controlling the physical properties of low-doped LBMO. Oxygen annealing seemed to induce strain and the strain accommodated in the films was relaxed by forming a secondary phase in an ordered rod-like shape or in particulate form

Association of Long Runs of Homozygosity With Alzheimer Disease Among African American Individuals

Science.gov (United States)

Ghani, Mahdi; Reitz, Christiane; Cheng, Rong; Vardarajan, Badri Narayan; Jun, Gyungah; Sato, Christine; Naj, Adam; Rajbhandary, Ruchita; Wang, Li-San; Valladares, Otto; Lin, Chiao-Feng; Larson, Eric B.; Graff-Radford, Neill R.; Evans, Denis; De Jager, Philip L.; Crane, Paul K.; Buxbaum, Joseph D.; Murrell, Jill R.; Raj, Towfique; Ertekin-Taner, Nilufer; Logue, Mark; Baldwin, Clinton T.; Green, Robert C.; Barnes, Lisa L.; Cantwell, Laura B.; Fallin, M. Daniele; Go, Rodney C. P.; Griffith, Patrick A.; Obisesan, Thomas O.; Manly, Jennifer J.; Lunetta, Kathryn L.; Kamboh, M. Ilyas; Lopez, Oscar L.; Bennett, David A.; Hendrie, Hugh; Hall, Kathleen S.; Goate, Alison M.; Byrd, Goldie S.; Kukull, Walter A.; Foroud, Tatiana M.; Haines, Jonathan L.; Farrer, Lindsay A.; Pericak-Vance, Margaret A.; Lee, Joseph H.; Schellenberg, Gerard D.; St. George-Hyslop, Peter; Mayeux, Richard; Rogaeva, Ekaterina

2015-01-01

IMPORTANCE Mutations in known causal Alzheimer disease (AD) genes account for only 1% to 3% of patients and almost all are dominantly inherited. Recessive inheritance of complex phenotypes can be linked to long (>1-megabase [Mb]) runs of homozygosity (ROHs) detectable by single-nucleotide polymorphism (SNP) arrays. OBJECTIVE To evaluate the association between ROHs and AD in an African American population known to have a risk for AD up to 3 times higher than white individuals. DESIGN, SETTING, AND PARTICIPANTS Case-control study of a large African American data set previously genotyped on different genome-wide SNP arrays conducted from December 2013 to January 2015. Global and locus-based ROH measurements were analyzed using raw or imputed genotype data. We studied the raw genotypes from 2 case-control subsets grouped based on SNP array: Alzheimer’s Disease Genetics Consortium data set (871 cases and 1620 control individuals) and Chicago Health and Aging Project–Indianapolis Ibadan Dementia Study data set (279 cases and 1367 control individuals). We then examined the entire data set using imputed genotypes from 1917 cases and 3858 control individuals. MAIN OUTCOMES AND MEASURES The ROHs larger than 1 Mb, 2 Mb, or 3 Mb were investigated separately for global burden evaluation, consensus regions, and gene-based analyses. RESULTS The African American cohort had a low degree of inbreeding (F ~ 0.006). In the Alzheimer’s Disease Genetics Consortium data set, we detected a significantly higher proportion of cases with ROHs greater than 2 Mb (P = .004) or greater than 3 Mb (P = .02), as well as a significant 114-kilobase consensus region on chr4q31.3 (empirical P value 2 = .04; ROHs >2 Mb). In the Chicago Health and Aging Project–Indianapolis Ibadan Dementia Study data set, we identified a significant 202-kilobase consensus region on Chr15q24.1 (empirical P value 2 = .02; ROHs >1 Mb) and a cluster of 13 significant genes on Chr3p21.31 (empirical P value 2 = .03

The diagnostic value of both troponin T and creatinine kinase isoenzyme (CK-MB in detecting combined renal and myocardial injuries in asphyxiated infants.

Directory of Open Access Journals (Sweden)

Wilson E Sadoh

Full Text Available Troponin T (cTnT and Creatinine Kinase Isoenzyme (CK-MB are both markers of myocardial injuries. However, CK-MB is also elevated in acute kidney injury.The diagnostic value of both cTnT and cardiac CK-MB in combined myocardial and acute kidney injuries (AKI in asphyxiated neonates was evaluated.40 asphyxiated infants and 40 non-asphyxiated controls were consecutively recruited. Serum levels of cTnT, CK-MB and creatinine were measured. Myocardial injury and AKI were defined as cTnT >95th percentile of the control and serum creatinine >1.0 mg/dl respectively.Of the 40 subjects, 9 (22.50%, 8 (20.00% and 4 (10.00% had myocardial injury, AKI and combined AKI and myocardial injuries respectively. The mean cTnT and CK-MB values were highest in infants with combined AKI and myocardial injuries. The Mean cTnT in infants with AKI, myocardial injury and combined AKI and myocardial injuries were 0.010±0.0007 ng/ml, 0.067±0.040 ng/ml and 0.084±0.067 ng/ml respectively, p = 0.006. The mean CK-MB in infants with AKI, myocardial injury and combined AKI and myocardial injuries were 2.78±0.22 ng/ml, 1.28±0.11 ng/ml and 4.58±0.52 ng/ml respectively, p = <0.0001.In severe perinatal asphyxia, renal and myocardial injuries could co-exist. Elevated cTnT signifies the presence of myocardial injury. Elevated CK-MB indicates either myocardial injury, AKI or both. Therefore renal injury should be excluded in asphyxiated infants with elevated CK-MB.

Reactor IPEN/MB-01 dosimetry using TLDs

Energy Technology Data Exchange (ETDEWEB)

Cavalieri, Tássio A.; Siqueira, Paulo T.D.; Yoriyaz, Hélio, E-mail: tassio.cavalieri@usp.br [Instituto de Pesquisas Energética s e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

This paper is a preliminary study on the use of reactor IPEN/MB-01 as standard radiation source for mixed field dosimetry studies. As a first step on this attempt, simulations and experiments, evaluating the neutron and gamma field distributions, were performed and compared. TLDs are widely employed in dose measurements and the TLD 100 / TLD 700 pair conforms with ICRU recommendations for mixed field dosimetry. In this study, TLD irradiations were performed in the IPEN/MB-01 nuclear reactor. IPEN/MB-01 reactor is zero power reactor widely used to perform reactor physics experiments. Its neutron flux distribution is well known for a variety of reactor core configurations. However, the photon fluxes are unknown. A series of experiments with TLD 100 and TLD 700 were performed for two different core configurations (rectangular and cylindrical with a central flux trap). Simulations with MCNP5 for these two configurations were also done, and neutron and gamma fluxes distributions along the core were computed. The responses of TLD 100 and TLD 700 were compared with simulated fluxes and showing a good agreement between them. This paper presents the results of the experiments done so far given the status of the study under way in order to couple IPEN/MB-01 and TLD 100 / 700 pair into a mixed field calibration methodology. (author)

Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}+Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} composite cathode for cermet supported thin Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} electrolyte SOFC operating below 600{sup o}C

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xinge; Robertson, Mark; Yick, Sing; Deces-Petit, Cyrille; Styles, Edward; Qu, Wei; Xie, Yongsong; Hui, Rob; Roller, Justin; Kesler, Olivera; Maric, Radenka; Ghosh, Dave [Institute for Fuel Cell Innovation, National Research Council Canada, 3250 East Mall, Vancouver, BC (Canada V6T 1W5)

2006-10-06

The cathode is a key component in low temperature solid oxide fuel cells. In this study, composite cathode, 75wt.% Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3} (SSC)+25wt.% Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (SDC), was applied on the cermet supported thin SDC electrolyte cell which was fabricated by tape casting, screen-printing, and co-firing. Single cells with the composite cathodes sintered at different temperatures were tested from 400 to 650{sup o}C. The best cell performance, 0.75Wcm{sup -2} peak power operating at 600{sup o}C, was obtained from the 1050{sup o}C sintered cathode. The measured thin SDC electrolyte resistance R{sub s} was 0.128{omega}cm{sup 2} and total electrode polarization R{sub p}(a+c) was only 0.102{omega}cm{sup 2} at 600{sup o}C. (author)

Recurring sets of recurring starspot occultations on exoplanet host Qatar-2

Science.gov (United States)

Močnik, T.; Southworth, J.; Hellier, C.

2017-10-01

We announce the detection of recurring sets of recurring starspot occultation events in the short-cadence K2 light curve of Qatar-2, a K dwarf star transited every 1.34 d by a hot Jupiter. In total, we detect 34 individual starspot occultation events, caused by five different starspots, occulted in up to five consecutive transits or after a full stellar rotation. The longest recurring set of recurring starspot occultations spans over three stellar rotations, setting a lower limit for the longest starspot lifetime of 58 d. Starspot analysis provided a robust stellar rotational period measurement of 18.0 ± 0.2 d and indicates that the system is aligned, having a sky-projected obliquity of 0° ± 8°. A pronounced rotational modulation in the light curve has a period of 18.2 ± 1.6 d, in agreement with the rotational period derived from the starspot occultations. We tentatively detect an ellipsoidal modulation in the phase curve, with a semi-amplitude of 18 ppm, but cannot exclude the possibility that this is the result of red noise or imperfect removal of the rotational modulation. We detect no transit-timing and transit-duration variations with upper limits of 15 s and 1 min, respectively. We also reject any additional transiting planets with transit depths above 280 ppm in the orbital period region 0.5-30 d.

Collective flow in 2.76 and 5.02 A TeV Pb + Pb collisions

Energy Technology Data Exchange (ETDEWEB)

Zhao, Wenbin; Xu, Hao-jie [Peking University, Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Song, Huichao [Peking University, Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Peking University, Center for High Energy Physics, Beijing (China)

2017-09-15

In this paper, we study and predict flow observables in 2.76 and 5.02 A TeV Pb + Pb collisions, using the iEBE-VISHNU hybrid model with TRENTo and AMPT initial conditions and with different forms of the QGP transport coefficients. With properly chosen and tuned parameter sets, our model calculations can nicely describe various flow observables in 2.76 A TeV Pb + Pb collisions, as well as the measured flow harmonics of all charged hadrons in 5.02 A TeV Pb + Pb collisions. We also predict other flow observables, including v{sub n}(p{sub T}) of identified particles, event-by-event v{sub n} distributions, event-plane correlations, (normalized) symmetric cumulants, non-linear response coefficients and p{sub T}-dependent factorization ratios, in 5.02 A TeV Pb + Pb collisions. We find many of these observables to remain approximately the same values as the ones in 2.76 A TeV Pb + Pb collisions. Our theoretical studies and predictions could shed light to the experimental investigations in the near future. (orig.)

The action of silicon doping in the first two to five barriers of eight periods In{sub 0.2}Ga{sub 0.8}N/GaN multiple quantum wells of blue LEDs

Energy Technology Data Exchange (ETDEWEB)

Chen, Meng-Chu [Department of Applied Science, National Taitung University, Taitung 950, Taiwan (China); Cheng, Yung-Chen, E-mail: chengyc@mail.nutn.edu.tw [Department of Materials Science, National University of Tainan, Tainan 70005, Taiwan (China); Huang, Chun-Yuan [Department of Applied Science, National Taitung University, Taitung 950, Taiwan (China); Wang, Hsiang-Chen [Advanced Institute of Manufacturing with High-tech Innovations (AIM-HI), National Chung Cheng University, Chia-Yi 62102, Taiwan (China); Lin, Kuang-I [Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan (China); Yang, Zu-Po [Institute of Photonic System, National Chiao Tung University, Tainan 71150, Taiwan (China)

2016-09-15

First two to five barriers in the growth sequence having silicon (Si) doping of eight periods In{sub 0.2}Ga{sub 0.8}N/GaN quantum wells (QWs) on twenty pairs of In{sub 0.02}Ga{sub 0.98}N/GaN superlattice strain relief layers (SRLs) of blue LEDs were prepared by low pressure metal–organic chemical vapor deposition (LPMOCVD) system on patterned sapphire substrates (PSSs). The effect of doping layers on the luminescence properties of QWs of blue LEDs was investigated. For the sample with first four barriers having Si doping, formation of soft confinement of QWs potential and strong carrier localization inside QWs were occurred. There is better spread of carriers among eight QWs and strong radiative recombination of carriers inside QWs. The increase of output power and external quantum efficiency (EQE) is due to decrease of Auger processes, leakage of carriers out of QWs, and nonradiative recombination centers. The consequences demonstrate that first four barriers with Si doping possess the favorable doping condition for eight periods In{sub 0.2}Ga{sub 0.8}N/GaN QWs.

Noninvasive ultrasound molecular imaging of the effect of statins on endothelial inflammatory phenotype in early atherosclerosis.

Directory of Open Access Journals (Sweden)

Elham Khanicheh

Full Text Available BACKGROUND/OBJECTIVES: Inflammatory changes on the endothelium are responsible for leukocyte recruitment to plaques in atherosclerosis. Noninvasive assessment of treatment-effects on endothelial inflammation may be of use for managing medical therapy and developing novel therapies. We hypothesized that molecular imaging of vascular cell adhesion molecule-1 (VCAM-1 with contrast enhanced ultrasound (CEU could assess treatment effects on endothelial phenotype in early atherosclerosis. METHODS: Mice with atherosclerosis produced by gene deletion of the LDL-receptor and Apobec-1-editing protein were studied. At 12 weeks of age, mice received 8 weeks of regular chow or atorvastatin-enriched chow (10 mg/kg/day. At 20 weeks, CEU molecular imaging for aortic endothelial VCAM-1 expression was performed with VCAM-1-targeted (MB(VCAM and control microbubbles (MB(Ctr. Aortic wall thickness was assessed with high frequency ultrasound. Histology, immunohistology and Western blot were used to assess plaque burden and VCAM-1 expression. RESULTS: Plaque burden was reduced on histology, and VCAM-1 was reduced on Western blot by atorvastatin, which corresponded to less endothelial expression of VCAM-1 on immunohistology. High frequency ultrasound did not detect differences in aortic wall thickness between groups. In contrast, CEU molecular imaging demonstrated selective signal enhancement for MB(VCAM in non-treated animals (MB(VCAM 2±0.3 vs MB(Ctr 0.7±0.2, p<0.01, but not in statin-treated animals (MB(VCAM 0.8±0.2 vs MB(Ctr 1.0±0.2, p = ns; p<0.01 for the effect of statin on MB(VCAM signal. CONCLUSIONS: Non-invasive CEU molecular imaging detects the effects of anti-inflammatory treatment on endothelial inflammation in early atherosclerosis. This easily accessible, low-cost technique may be useful in assessing treatment effects in preclinical research and in patients.

Protein Kinase G facilitates EGFR-mediated cell death in MDA-MB-468 cells

Energy Technology Data Exchange (ETDEWEB)

Jackson, Nicole M.; Ceresa, Brian P., E-mail: brian.ceresa@louisville.edu

2016-08-15

The Epidermal Growth Factor Receptor (EGFR) is a transmembrane receptor tyrosine kinase with critical implications in cell proliferation, migration, wound healing and the regulation of apoptosis. However, the EGFR has been shown to be hyper-expressed in a number of human malignancies. The MDA-MB-468 metastatic breast cell line is one example of this. This particular cell line hyper-expresses the EGFR and undergoes EGFR-mediated apoptosis in response to EGF ligand. The goal of this study was to identify the kinases that could be potential intermediates for the EGFR-mediated induction of apoptosis intracellularly. After identifying Cyclic GMP-dependent Protein Kinase G (PKG) as a plausible intermediate, we wanted to determine the temporal relationship of these two proteins in the induction of apoptosis. We observed a dose-dependent decrease in MDA-MB-468 cell viability, which was co-incident with increased PKG activity as measured by VASPSer239 phosphorylation. In addition, we observed a dose dependent decrease in cell viability, as well as an increase in apoptosis, in response to two different PKG agonists, 8-Bromo-cGMP and 8-pCPT-cGMP. MDA-MB-468 cells with reduced PKG activity had attenuated EGFR-mediated apoptosis. These findings indicate that PKG does not induce cell death via transphosphorylation of the EGFR. Instead, PKG activity occurs following EGFR activation. Together, these data indicate PKG as an intermediary in EGFR-mediated cell death, likely via apoptotic pathway.

Comparison of early myocardial technetium-99m pyrophosphate uptake to early peaking of creatine kinase and creatine kinase-MB as indicators of early reperfusion in acute myocardial infarction

International Nuclear Information System (INIS)

Kondo, M.; Yuzuki, Y.; Arai, H.; Shimizu, K.; Morikawa, M.; Shimono, Y.

1987-01-01

The value of technetium-99m pyrophosphate (Tc-99m-PYP) scintigraphy as an indicator of reperfusion 2.8 to 8 hours after the onset of symptoms of acute myocardial infarction was compared with the value of early peak creatine kinase (CK) and CK-MB release within 16 hours after the onset of symptoms. In 29 patients who received thrombolytic therapy, recanalization was seen (group 1) and in 7 it was not (group 2). In 23 patients (79%) in group 1 scintigraphic findings were positive and in all 7 in group 2 they were negative. In 15 patients (52%) in group 1 and 1 patient (14%) in group 2, CK reached its peak level within 16 hours. In 20 patients (69%) in group 1 and 3 (43%) in group 2 the CK-MB level reached a peak within 16 hours. The sensitivity, specificity and predictive accuracy of positive results of early Tc-99m-PYP scintigraphy in predicting the reperfusion were 79%, 100% and 83%. These values are significantly higher than or similar to those of early peaking of CK and CK-MB release. In contrast to measurements of enzyme release, reperfusion data for Tc-99m-PYP scintigraphy are available immediately after thrombolytic therapy. Therefore, early Tc-99m-PYP scintigraphy (3 to 8 hours after onset of symptoms) is valuable as a noninvasive technique for early diagnosis of reperfusion

Diffusion Monte Carlo studies of MB-pol (H{sub 2}O){sub 2−6} and (D{sub 2}O){sub 2−6} clusters: Structures and binding energies

Energy Technology Data Exchange (ETDEWEB)

Mallory, Joel D.; Mandelshtam, Vladimir A. [Department of Chemistry, University of California, Irvine, California 92697 (United States)

2016-08-14

We employ the diffusion Monte Carlo (DMC) method in conjunction with the recently developed, ab initio-based MB-pol potential energy surface to characterize the ground states of small (H{sub 2}O){sub 2−6} clusters and their deuterated isotopomers. Observables, other than the ground state energies, are computed using the descendant weighting approach. Among those are various spatial correlation functions and relative isomer fractions. Interestingly, the ground states of all clusters considered in this study, except for the dimer, are delocalized over at least two conformations that differ by the orientation of one or more water monomers with the relative isomer populations being sensitive to the isotope substitution. Most remarkably, the ground state of the (H{sub 2}O){sub 6} hexamer is represented by four distinct cage structures, while that of (D{sub 2}O){sub 6} is dominated by the prism, i.e., the global minimum geometry, with a very small contribution from a prism-book geometry. In addition, for (H{sub 2}O){sub 6} and (D{sub 2}O){sub 6}, we performed DMC calculations to compute the ground states constrained to the cage and prism geometries. These calculations compared results for three different potentials, MB-pol, TTM3/F, and q-TIP4P/F.

Engineering Mixed Ionic Electronic Conduction in La 0.8 Sr 0.2 MnO 3+ δ Nanostructures through Fast Grain Boundary Oxygen Diffusivity

KAUST Repository

Saranya, Aruppukottai M.

2015-04-09

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Nanoionics has become an increasingly promising field for the future development of advanced energy conversion and storage devices, such as batteries, fuel cells, and supercapacitors. Particularly, nanostructured materials offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. However, the enhancement of the mass transport properties at the nanoscale has often been found to be difficult to implement in nanostructures. Here, an artificial mixed ionic electronic conducting oxide is fabricated by grain boundary (GB) engineering thin films of La0.8Sr0.2MnO3+δ. This electronic conductor is converted into a good mixed ionic electronic conductor by synthesizing a nanostructure with high density of vertically aligned GBs with high concentration of strain-induced defects. Since this type of GBs present a remarkable enhancement of their oxide-ion mass transport properties (of up to six orders of magnitude at 773 K), it is possible to tailor the electrical nature of the whole material by nanoengineering, especially at low temperatures. The presented results lead to fundamental insights into oxygen diffusion along GBs and to the application of these engineered nanomaterials in new advanced solid state ionics devices such are micro-solid oxide fuel cells or resistive switching memories. An electronic conductor such as La0.8Sr0.2MnO3+δ is converted into a good mixed ionic electronic conductor by synthesizing a nanostructure with excellent electronic and oxygen mass transport properties. Oxygen diffusion highways are created by promoting a high concentration of strain-induced defects in the grain boundary region. This novel strategy opens the way for synthesizing new families of artificial mixed ionic-electronic conductors by design.

Lead-free Ba0.8Ca0.2(ZrxTi1−x)O3 ceramics with large electrocaloric effect

International Nuclear Information System (INIS)

Asbani, B.; Dellis, J.-L.; Lahmar, A.; Gagou, Y.; El Marssi, M.; Courty, M.; Djellab, K.; Amjoud, M.; Mezzane, D.; Kutnjak, Z.

2015-01-01

The electrocaloric effect was investigated in lead-free Zr doped Ba 0.8 Ca 0.2 (Zr x Ti 1−x )O 3 (BCTZ) ceramics synthesized by a conventional sintering process. Room-temperature x-ray diffraction analysis showed that the tetragonal structure is obtained in BCTZ for x ≤ 0.08 and a pseudo cubic phase for x > 0.08. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of Zr doping and that the BCTZ exhibits a first order ferroelectric phase transition. The electrocaloric effect was determined by the calculation of the electrocaloric change of temperature (ΔT) using the Maxwell relation based on the P–E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ΔT/ΔE = 0.34 × 10 −6  Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials

Characterization of the yttria-stabilized zirconia thin film electrophoretic deposited on La{sub 0.8}Sr{sub 0.2}MnO{sub 3} substrate

Energy Technology Data Exchange (ETDEWEB)

Yang, Koho [Department of Mold and Die Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Rode, Kaohsiung 80782, Taiwan (China); Shen, Jung-Hsiung [Department of Mold and Die Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Rode, Kaohsiung 80782, Taiwan (China); Yang, Kai-Yun [Department of Materials Science and Engineering, National Chen Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hung, I-Ming [Department of Materials Science and Engineering, National Chen Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Department of Chemical Engineering and Materials Science, Yuan Ze University, 135 Yuan-Tung Road, Chungli, Taoyunn 320, Taiwan (China); Fung, Kuan-Zong [Department of Materials Science and Engineering, National Chen Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Wang, Moo-Chin [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 807, Taiwan (China)]. E-mail: mcwang@kmu.edu.tw

2007-06-14

The yttria-stabilized zirconia (YSZ) thin films electrophoretic deposited on the La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) substrate have been characterized by using zeta potential analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The La{sub 2}Zr{sub 2}O{sub 7} (LZ) formed at the interface between the YSZ thin film and LSM substrate, after sintered at 1400 {sup o}C for 52 h, are identified by XRD. The zeta potential of the YSZ particles in pure ethanol-acetone is about 7.8 mV, but when the I{sub 2} concentration is greater than 0.6 g/1, the zeta potential attains a constant value, 46 mV. The relation between deposit weight of the YSZ films and the applied voltage shows a non-linear behavior. Thickness of the YSZ thin film deposited on the LSM substrate by electrophoretic deposition is controlled by a diffusion process. A larger LZ with the thickness of 200 nm is formed at the interface between the YSZ film and the LSM substrate.

Microstructure, crystal structure and electrical properties of Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramics obtained at different sintering conditions

Energy Technology Data Exchange (ETDEWEB)

Bodak, O.; Akselrud, L.; Demchenko, P.; Kotur, B.; Mrooz, O.; Hadzaman, I.; Shpotyuk, O.; Aldinger, F.; Seifert, H.; Volkov, S.; Pekhnyo, V

2002-12-16

Details of the formation of Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramics under different sintering conditions have been studied by optical microscopy, scanning electron microscopy (SEM), electron probe and energy dispersive spectroscopy (EDX) microanalyses, X-ray diffraction (XRD) and electrical resistivity measurements. Microstructure studies of samples sintered at 1170 deg. C for 1 h indicated the presence of a secondary phase besides the main spinel phase with modified composition. XRD measurements showed that the spinel phase exhibits a tetragonally distorted spinel structure (space group I4{sub 1}/amd, a=5.9410(5) A, c=8.4196(15) A). The secondary phase (solid solution based on NiO) crystallizes with the NaCl-type structure (space group Fm3-bar m, a=4.1872(3) A). The content of the secondary phase in ceramics is 10.61 mass%. For NiMn{sub 2}O{sub 4} ceramics, prepared under the same sintering conditions, the decomposition with Ni{sub 1-x}Mn{sub x}O solid solution (NaCl-type structure) and spinel phase formation have been observed. The tetragonal modification of the spinel phase for NiMn{sub 2}O{sub 4} ceramics is more preferable (space group I4{sub 1}/amd, a=5.9764(5) A, c=8.4201(8) A). The distribution of atoms in the structure has been proposed for both ceramics. According to XRD results the Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramic samples, sintered at 920 deg. C for 8 h (program 1), at 920 deg. C for 8 h and at 750 deg. C for 24 h (program 2), at 920 deg. C for 8 h, at 1200 deg. C for 1 h and at 920 deg. C for 24 h (program 3) and at 920 deg. C for 8 h, at 1200 deg. C for 1 h, at 920 deg. C for 24 h and at 750 deg. C for 48 h (program 4), contain a single phase with the cubic spinel structure (space group Fd3-bar m). Small residuals of the secondary phase for the ceramics, prepared via programs 3 and 4, have been observed by SEM investigations. The structure transformations of the spinel phase for Cu{sub 0.1}Ni{sub 0.8}Co

A novel bilayered Sr{sub 0.6}La{sub 0.4}TiO{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} interconnector for anode-supported tubular solid oxide fuel cell via slurry-brushing and co-sintering process

Energy Technology Data Exchange (ETDEWEB)

Xu, Yanjie; Wang, Shaorong; Liu, Renzhu; Wen, Tinglian; Wen, Zhaoyin [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2011-02-01

Considering that conventional lanthanum chromate (LaCrO{sub 3}) interconnector is hard to be co-sintered with green anode, we have fabricated a novel bilayered interconnector which consists of La-doped SrTiO{sub 3} (Sr{sub 0.6}La{sub 0.4}TiO{sub 3}) and Sr-doped lanthanum manganite (La{sub 0.8}Sr{sub 0.2}MnO{sub 3}). Sr{sub 0.6}La{sub 0.4}TiO{sub 3} is conductive and stable in reducing atmosphere, locating on the anode side; while La{sub 0.8}Sr{sub 0.2}MnO{sub 3} is on the cathode side. A slurry-brushing and co-sintering method is applied: the Sr{sub 0.6}La{sub 0.4}TiO{sub 3} and La{sub 0.8}Sr{sub 0.2}MnO{sub 3} slurries are successively brushed onto green anode specimen, followed by co-firing course to form a dense bilayered Sr{sub 0.6}La{sub 0.4}TiO{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} interconnector. For operating with humidified hydrogen and oxygen at 900 C, the ohmic resistances between anode and cathode/interconnector are 0.33 {omega} cm{sup 2} and 0.186 {omega} cm{sup 2}, respectively. The maximum power density is 290 mW cm{sup -2} for a cell with interconnector, and 420 mW cm{sup -2} for a cell without it, which demonstrates that nearly 70% of the power output can be achieved using this bilayered Sr{sub 0.6}La{sub 0.4}TiO{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} interconnector. (author)

Synthesis and Evaluation of in Vitro Biological Activity of 4-Substituted Arylpiperazine Derivatives of 1,7,8,9-Tetrachloro-10,10-dimethoxy-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione

Directory of Open Access Journals (Sweden)

David Collu

2009-12-01

Full Text Available A series of twenty arylpiperazine derivatives of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione have been prepared. These derivatives were tested in vitro with the aim of identifying novel lead compounds active against emergent and re-emergent human and cattle infectious diseases (AIDS, hepatitis B and C, tuberculosis, bovine viral diarrhea. In particular, these compounds were evaluated in vitro against representatives of different virus classes, such as a HIV-1 (Retrovirus, a HBV (Hepadnavirus and the single-stranded RNA+ viruses Yellow fever virus (YFV and Bovine viral diarrhea virus (BVDV, both belonging to the Flaviridae. Compounds 2c, 2g and 3d showed a modest activity against CVB-2. The molecular structures of the starting imide 1 and one of propyl-piperazine derivatives, 3b, have been determined by an X-ray crystallography study.

Sintering time effect on crystal structure and magnetic properties of Bi{sub 0.8}La{sub 0.2}FeO{sub 3} multiferroics

Energy Technology Data Exchange (ETDEWEB)

Singh, Ompal, E-mail: om19901990@gmail.com; Agarwal, Ashish; Sanghi, Sujata; Singh, Jogender [Department of Applied Physics Guru Jambheshwar University of Science & Technology, Hisar – 125001 (Haryana) (India)

2016-05-06

Effect of sintering time over the structure and magnetic properties has been studied in Bi{sub 0.8}La{sub 0.2}FeO{sub 3} multiferroic ceramics prepared by solid state reaction technique. The structure changes with the advent mixed phase rhombohedral and orthorhombic symmetry to immaculate orthorhombic structure with sintering time from 2 to 3 hour, as revealed by means of the simulation of XRD patterns via Rietveld analysis through FullProf software. The M – H plots depict decent enhancement in magnetization with values of remnant magnetization (Mr) from 0.01868emu/g to 0.09357emu/g while the sintering time is varied from 2 to 3 hour. The metamagnetic transition may be attributed to the crumpling of the modulated spin cycloid existing inherently in the pristine compound. The presented study may have considerable impact in commercial as well as advanced electronic applications.

Complete Circular Genome Sequence of Successful ST8/SCCmecIV Community-Associated Methicillin-Resistant Staphylococcus aureus (OC8 in Russia: One-Megabase Genomic Inversion, IS256's Spread, and Evolution of Russia ST8-IV.

Directory of Open Access Journals (Sweden)

Tsai-Wen Wan

Full Text Available ST8/SCCmecIV community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA has been a common threat, with large USA300 epidemics in the United States. The global geographical structure of ST8/SCCmecIV has not yet been fully elucidated. We herein determined the complete circular genome sequence of ST8/SCCmecIVc strain OC8 from Siberian Russia. We found that 36.0% of the genome was inverted relative to USA300. Two IS256, oppositely oriented, at IS256-enriched hot spots were implicated with the one-megabase genomic inversion (MbIN and vSaβ split. The behavior of IS256 was flexible: its insertion site (att sequences on the genome and junction sequences of extrachromosomal circular DNA were all divergent, albeit with fixed sizes. A similar multi-IS256 system was detected, even in prevalent ST239 healthcare-associated MRSA in Russia, suggesting IS256's strong transmission potential and advantage in evolution. Regarding epidemiology, all ST8/SCCmecIVc strains from European, Siberian, and Far Eastern Russia, examined had MbIN, and geographical expansion accompanied divergent spa types and resistance to fluoroquinolones, chloramphenicol, and often rifampicin. Russia ST8/SCCmecIVc has been associated with life-threatening infections such as pneumonia and sepsis in both community and hospital settings. Regarding virulence, the OC8 genome carried a series of toxin and immune evasion genes, a truncated giant surface protein gene, and IS256 insertion adjacent to a pan-regulatory gene. These results suggest that unique single ST8/spa1(t008/SCCmecIVc CA-MRSA (clade, Russia ST8-IVc emerged in Russia, and this was followed by large geographical expansion, with MbIN as an epidemiological marker, and fluoroquinolone resistance, multiple virulence factors, and possibly a multi-IS256 system as selective advantages.

Complete Circular Genome Sequence of Successful ST8/SCCmecIV Community-Associated Methicillin-Resistant Staphylococcus aureus (OC8) in Russia: One-Megabase Genomic Inversion, IS256's Spread, and Evolution of Russia ST8-IV.

Science.gov (United States)

Wan, Tsai-Wen; Khokhlova, Olga E; Iwao, Yasuhisa; Higuchi, Wataru; Hung, Wei-Chun; Reva, Ivan V; Singur, Olga A; Gostev, Vladimir V; Sidorenko, Sergey V; Peryanova, Olga V; Salmina, Alla B; Reva, Galina V; Teng, Lee-Jene; Yamamoto, Tatsuo

2016-01-01

ST8/SCCmecIV community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been a common threat, with large USA300 epidemics in the United States. The global geographical structure of ST8/SCCmecIV has not yet been fully elucidated. We herein determined the complete circular genome sequence of ST8/SCCmecIVc strain OC8 from Siberian Russia. We found that 36.0% of the genome was inverted relative to USA300. Two IS256, oppositely oriented, at IS256-enriched hot spots were implicated with the one-megabase genomic inversion (MbIN) and vSaβ split. The behavior of IS256 was flexible: its insertion site (att) sequences on the genome and junction sequences of extrachromosomal circular DNA were all divergent, albeit with fixed sizes. A similar multi-IS256 system was detected, even in prevalent ST239 healthcare-associated MRSA in Russia, suggesting IS256's strong transmission potential and advantage in evolution. Regarding epidemiology, all ST8/SCCmecIVc strains from European, Siberian, and Far Eastern Russia, examined had MbIN, and geographical expansion accompanied divergent spa types and resistance to fluoroquinolones, chloramphenicol, and often rifampicin. Russia ST8/SCCmecIVc has been associated with life-threatening infections such as pneumonia and sepsis in both community and hospital settings. Regarding virulence, the OC8 genome carried a series of toxin and immune evasion genes, a truncated giant surface protein gene, and IS256 insertion adjacent to a pan-regulatory gene. These results suggest that unique single ST8/spa1(t008)/SCCmecIVc CA-MRSA (clade, Russia ST8-IVc) emerged in Russia, and this was followed by large geographical expansion, with MbIN as an epidemiological marker, and fluoroquinolone resistance, multiple virulence factors, and possibly a multi-IS256 system as selective advantages.

The effect of doped zinc on the structural properties of nano-crystalline (Se{sub 0.8}Te{sub 0.2}){sub 100-x}Zn{sub x}

Energy Technology Data Exchange (ETDEWEB)

Kumar, Arun, E-mail: arunkumar82@pu.ac.in [Department of Physics, Panjab University, Chandigarh, INDIA-160014. (India); Guru Nanak National College, Doraha, Panjab, INDIA-141421. (India); Singh, Harkawal; Gill, P. S. [Sri Guru Gobind Singh College, Sector-26, Chandigarh, INDIA-160026. (India); Goyal, Navdeep, E-mail: n.goyal@pu.ac.in [Department of Physics, Panjab University, Chandigarh, INDIA-160014. (India)

2016-05-06

The effect of metallic zinc (Zn) on the structural properties of (Se{sub 0.8}Te{sub 0.2}){sub 1-X}Zn{sub X} (x=0, 2, 6, 8, 10) samples analyzed by X-ray Diffraction (XRD). The presence of sharp peaks in XRD patterns confirmed the crystalline nature of the samples and is indexed in orthorhombic crystal structure. XRD studies predicts that the average particle size of all the samples are about 46.29 nm, which is less than 100 nm and hence have strong tendency of agglomeration. Williamson-Hall plot method was used to evaluate the lattice strain. The dislocation density and no. of unit cells of the samples were calculated which show the inverse relation with each other. Morphology index derived from FWHM of XRD data explains the direct relationship with the particle size.

Magneto-transport and thermoelectric properties of La0.8-xBixCa0.2MnO3 manganites

International Nuclear Information System (INIS)

Manjunatha, S.O.; Rao, Ashok

2015-01-01

In the present work, we report the studies on the magneto-transport and thermoelectric properties of La 0.8-x Bi x Ca 0.2 MnO 3 (x = 0.00, 0.05, 0.10) manganites. The samples were prepared using the conventional solid state reaction method. Structural characterization has done using XRD. Rietveld refinement technique has confirmed the single phase formation of the samples with no impurity peaks observed within experimental limits. SEM micrograph confirms the formation of grains with good intimacy. The cell parameters and the unit cell volume is observed to decrease with increasing Bi concentration. It is attributed to the smaller ionic size of Bi compare to La. Magneto-resistance of the samples are measured using standard four probe technique. The Metal-Insulator transition (TMI) is found to decrease upon doping with overall increase in the resistivity. The observed effect is due to the fact that the Ca ions possibly increases the tendency of screening of 6s 2 orbital of Bi 3+ ions. As orientation of the 6s 2 lone pair toward a surrounding anion (O 2- ) produces a local distortion and as a result, the movement of eg electrons through the Mn-O-Mn bridges, is severely reduced. Resistance of the samples is observed to reduce on application of magnetic field of 8Tesla due to the fact that the magnetic field induces spin alignment and suppress the spin fluctuation resulting in large decrease in resistance. Thermopower measurement shows that all the samples are exhibiting the anomaly of phase transition from metal like behavior in low temperature to insulator like behavior at high temperature. As the temperature increases from 5K the pristine sample exhibit a small positive and nearly constant value of S till 172K. Then the value of S start to increase sharply and reaches a maximum value of ≈41μV/K at 234K and decreases rather sharply on further increase in temperature. The analysis of thermoelectric power data confirmed the validity of small polaron type conduction

2018-02-28T23:56:57Z https://www.ajol.info/index.php/all/oai oai:ojs ...

African Journals Online (AJOL)

article/60853 2018-02-28T23:56:57Z ejc:ART Attitudes of Women to Menopause: Implications for Counselling Osarenren, N Ubangha, M.B Nwadinigwe, I.P Ogunleye, T Menopause; Attitudes, Midlife; Aging; Counselling; Assertiveness training; ...

Vector models in RETRAN-02 MOD 2

International Nuclear Information System (INIS)

Kinnersly, S.R.

1985-06-01

The vector momentum model in RETRAN-02 allows momentum flux to be modelled in two dimensions. Vector models in RETRAN-2 are described, including both the actual implementation in the code and the specification given in the code manual. The vector momentum model is described in detail. Other models which use vector quantities include models for volume average flow, volume average slip velocity, volume average phase velocities and fill junction flows. Both code implementations and code manual descriptions are described and inconsistencies noted. The differences between the standard RETRA-02 Mod 2 version and the Winfrith version RETN2204 are noted. (U.K.)

A novel del(8)(q23.2q24.11) contributing to disease progression in a case of JAK2/TET2 double mutated chronic myelomonocytic leukemia

DEFF Research Database (Denmark)

Toft-Petersen, Marie; Kjeldsen, Eigil; Nederby, Line

2014-01-01

We have identified a novel 7.7 Mb del(8)(q23.2q24.11) in a patient progressing to acute myeloid leukemia (AML) following a 12-year stable phase of chronic myelomonocytic leukemia (CMML). A surprisingly high JAK2+ allelic burden of 92% at the time of AML led us to delineate the molecular aberrations...... relevant for leukemogenesis. While a frameshift mutation in the TET2 gene was stably present throughout the course of disease the JAK2 mutation was acquired after initial diagnosis of CMML. At progression aCGH revealed del(8q)(q23.2q24.11) encompassing various cancer relevant genes of which RAD21 and CSMD3...

Complete Circular Genome Sequence of Successful ST8/SCCmecIV Community-Associated Methicillin-Resistant Staphylococcus aureus (OC8) in Russia: One-Megabase Genomic Inversion, IS256’s Spread, and Evolution of Russia ST8-IV

Science.gov (United States)

Wan, Tsai-Wen; Higuchi, Wataru; Hung, Wei-Chun; Reva, Ivan V.; Singur, Olga A.; Gostev, Vladimir V.; Sidorenko, Sergey V.; Peryanova, Olga V.; Salmina, Alla B.; Reva, Galina V.; Teng, Lee-Jene; Yamamoto, Tatsuo

2016-01-01

ST8/SCCmecIV community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been a common threat, with large USA300 epidemics in the United States. The global geographical structure of ST8/SCCmecIV has not yet been fully elucidated. We herein determined the complete circular genome sequence of ST8/SCCmecIVc strain OC8 from Siberian Russia. We found that 36.0% of the genome was inverted relative to USA300. Two IS256, oppositely oriented, at IS256-enriched hot spots were implicated with the one-megabase genomic inversion (MbIN) and vSaβ split. The behavior of IS256 was flexible: its insertion site (att) sequences on the genome and junction sequences of extrachromosomal circular DNA were all divergent, albeit with fixed sizes. A similar multi-IS256 system was detected, even in prevalent ST239 healthcare-associated MRSA in Russia, suggesting IS256’s strong transmission potential and advantage in evolution. Regarding epidemiology, all ST8/SCCmecIVc strains from European, Siberian, and Far Eastern Russia, examined had MbIN, and geographical expansion accompanied divergent spa types and resistance to fluoroquinolones, chloramphenicol, and often rifampicin. Russia ST8/SCCmecIVc has been associated with life-threatening infections such as pneumonia and sepsis in both community and hospital settings. Regarding virulence, the OC8 genome carried a series of toxin and immune evasion genes, a truncated giant surface protein gene, and IS256 insertion adjacent to a pan-regulatory gene. These results suggest that unique single ST8/spa1(t008)/SCCmecIVc CA-MRSA (clade, Russia ST8-IVc) emerged in Russia, and this was followed by large geographical expansion, with MbIN as an epidemiological marker, and fluoroquinolone resistance, multiple virulence factors, and possibly a multi-IS256 system as selective advantages. PMID:27741255

Engineering of RuMb: Toward a Green Catalyst for Carbene Insertion Reactions.

Science.gov (United States)

Wolf, Matthew W; Vargas, David A; Lehnert, Nicolai

2017-05-15

The small, stable heme protein myoglobin (Mb) was modified through cofactor substitution and mutagenesis to develop a new catalyst for carbene transfer reactions. The native heme was removed from wild-type Mb and several Mb His64 mutants (H64D, H64A, H64V), and the resulting apoproteins were reconstituted with ruthenium mesoporphyrin IX (RuMpIX). The reconstituted proteins (RuMb) were characterized by UV-vis and circular dichroism spectroscopy and were used as catalysts for the N-H insertion of aniline derivatives and the cyclopropanation of styrene derivatives. The best catalysts for each reaction were able to achieve turnover numbers (TON) up to 520 for the N-H insertion of aniline, and 350 TON for the cyclopropanation of vinyl anisole. Our results show that RuMb is an effective catalyst for N-H insertion, with the potential to further increase the activity and stereoselectivity of the catalyst in future studies. Compared to native Mb ("FeMb"), RuMb is a more active catalyst for carbene transfer reactions, which leads to both heme and protein modification and degradation and, hence, to an overall much-reduced lifetime of the catalyst. This leads to lower TONs for RuMb compared to the iron-containing analogues. Strategies to overcome this limitation are discussed. Finally, comparison is also made to FeH64DMb and FeH64AMb, which have not been previously investigated for carbene transfer reactions.

Experimental Conditions: SE3_S02_M02_D02 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available SE3_S02_M02_D02 SE3 Comparison of fruit metabolites among tomato varieties 1 SE3_S0...2 Solanum lycopersicum House Momotaro fruit SE3_S02_M02 6.7 mg [MassBase ID] MDLC1_25530 SE3_MS1 LC-FT-ICR-M

Investigation on structural, magneto-transport, magnetic and thermal properties of La{sub 0.8}Ca{sub 0.2−x}Ba{sub x}MnO{sub 3} (0 ⩽ x ⩽ 0.2) manganites

Energy Technology Data Exchange (ETDEWEB)

Manjunatha, S.O. [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Rao, Ashok, E-mail: ashokanu_rao@rediffmail.com [Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Subhashini [Material Processing Laboratory, Department of Physics, National Institute of Technology Karnataka, Surathkal 575025 (India); Okram, G.S. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452 001, MP (India)

2015-08-15

Highlights: • Ba-doped compounds follow small polaron hopping model in high temperature range. • Ba-doping introduces structural phase transformation. • MR (%) decreases with Ba-doping, however T{sub MI} and T{sub C} increase with doping. • High temperature TEP data follows SPH model. • At low temperatures, electron–magnon scattering play role in thermal transport. - Abstract: A systematic study on the structural, electrical, magnetic and thermo-electric properties of La{sub 0.8}Ba{sub x}Ca{sub 0.2−x}MnO{sub 3} (0 ⩽ x ⩽ 0.2) manganites is carried out in the present work. The samples have been prepared using solid state reaction technique. All the samples are single phased. It is seen that Ba-doping introduces a structural phase transformation viz. from rhombohedral to cubic system. Electric and magnetic studies respectively show that the metal–insulator transition temperature, T{sub MI} and Curie temperature, T{sub C} increase with Ba-content. Magneto-resistance (MR) data shows that it decreases with Ba-doping. Analyses of the electrical transport data in metallic region i.e. T < T{sub MI} shows that the electrical transport is governed predominantly by electron–electron scattering process. On the other hand, the adiabatic small polaron hopping (ASPH) model is appropriate in the high-temperature insulating range viz. T > T{sub MI}. We have used the electrical resistivity data in the entire temperature range (50–300 K) and analyzed using the phenomenological percolation model which is based on the phase segregation mechanism. We have analyzed the Seebeck coefficient data which reveals that the small polaron hopping mechanism is operative in high temperature regime and the low temperature region is examined by taking into account the impurity, electron–magnon scattering, and spin wave fluctuation terms. It is established that the electron–magnon scattering is dominating for the thermoelectric transport below T{sub MI}.

Mechanisms underlying differential expression of interleukin-8 in breast cancer cells

Science.gov (United States)

Freund, Ariane; Jolivel, Valérie; Durand, Sébastien; Kersual, Nathalie; Chalbos, Dany; Chavey, Carine; Vignon, Françoise; Lazennec, Gwendal

2004-01-01

We have recently reported that Interleukin-8 (IL-8) expression was inversely correlated to estrogen-receptor (ER)-status and was overexpressed in invasive breast cancer cells. In the present study, we show that IL-8 overexpression in breast cancer cells involves a higher transcriptional activity of IL-8 gene promoter. Cloning of IL-8 promoter from MDA-MB-231 and MCF-7 cells expressing high and low levels of IL-8, respectively, shows the integrity of the promoter in both cell lines. Deletion and site-directed mutagenesis of the promoter demonstrate that NF-κB and AP-1 and to a lesser extent C/EBP binding sites play a crucial role in the control of IL-8 promoter activity in MDA-MB-231 cells. Knock-down of NF-κB and AP-1 activities by adenovirus-mediated expression of a NF-κB super-repressor and RNA interference, respectively, decreased IL-8 expression in MDA-MB-231 cells. On the contrary, restoration of Fra-1, Fra-2, c-Jun, p50, p65, C/EBPα and C/EBPβ expression levels in MCF-7 cells led to a promoter activity comparable to that observed in MDA-MB-231 cells. Our data constitute the first extensive study of IL-8 gene overexpression in breast cancer cells and suggest that the high expression of IL-8 in invasive cancer cells requires a complex cooperation between NF-κB, AP-1 and C/EBP transcription factors. PMID:15208657

Determination of oxygen nonstoichiometry and diffusivity in mixed conducting oxides by oxygen Coulometric titration. II. Oxygen nonstoichiometry and defect model for La0.8Sr0.2CoO3-d

NARCIS (Netherlands)

Lankhorst, M.H.R.; Lankhorst, M.H.R.; Bouwmeester, Henricus J.M.

1997-01-01

The oxygen nonstoichiometry of La0.8Sr0.2CoO3-delta has been determined as a function of oxygen partial pressure and temperature using a high-temperature coulometric titration cell. For each measured value of the oxygen chemical potential, the oxygen nonstoichiometry is found to be nearly

Structural and dielectric properties of (001) and (111)-oriented BaZr0.2Ti0.8O3 epitaxial thin films

International Nuclear Information System (INIS)

Ventura, J.; Fina, I.; Ferrater, C.; Langenberg, E.; Coy, L.E.; Polo, M.C.; Garcia-Cuenca, M.V.; Fabrega, L.; Varela, M.

2010-01-01

We have grown and characterized BaZr 0.2 Ti 0.8 O 3 (BZT) epitaxial thin films deposited on (001) and (111)-oriented SrRuO 3 -buffered SrTiO 3 substrates by pulsed laser deposition. Structural and morphological characterizations were performed using X-ray diffractometry and atomic force microscopy, respectively. A cube-on-cube epitaxial relationship was ascertained from the θ-2θ and φ diffractograms in both (001) and (111)-oriented films. The (001)-oriented films showed a smooth granular morphology, whereas the faceted pyramid-like crystallites of the (111)-oriented films led to a rough surface. The dielectric response of BZT at room temperature was measured along the growth direction. The films were found to be ferroelectric, although a well-saturated hysteresis loop was obtained only for the (001)-oriented films. High leakage currents were observed for the (111) orientation, likely associated to charge transport along the boundaries of its crystallites. The remanent polarization, coercive field, dielectric constant, and relative change of dielectric permittivity (tunability) of (111)-oriented BZT were higher than those of (001)-oriented BZT.

Preparation and dielectric properties of Ba0.95Ca0.05Ti0.8Zr0.2O3-polyethersulfone composites

International Nuclear Information System (INIS)

Wang Fajun; Li Wen; Jiang Hongliu; Xue Mingshan; Lu Jinshan; Yao Junping

2010-01-01

We report the preparation and dielectric properties of ceramic-polymer composites using Ba 0.95 Ca 0.05 Ti 0.8 Zr 0.2 O 3 (BCTZ) as a ceramic filler and polyethersulfone (PES) as a polymer matrix. The BCTZ powders were synthesized by a sol-gel method to fabricate BCZT-PES composites. The composites with various BCTZ volume fractions were prepared by a solution mixing and hot-pressing method. The composite with 50 vol % BCTZ showed high dielectric constant (ε=48.80) and low loss (tan δ=0.042) at 1 kHz and room temperature. Such excellent dielectric properties of the composites displayed an acceptable stability within a wide range of temperature (from 20 to 150 deg. C) and frequency (from 100 Hz to 100 kHz). The present work indicates that the BCTZ-PES composite can be a candidate for embedded capacitors.

Long time relaxation of resistance in La0.8Sr0.2MnO3 ceramics and La0.65Ca0.35 MnO3 films on ferroelectric substrates

International Nuclear Information System (INIS)

Medvedev, Yu.V.; Mezin, N.I.; Nikolaenko, Yu.M.; Pigur, A.E.; Shishkova, N.V.; Ishchuk, V.M.; Chukanova, I.N.

2004-01-01

Galvanomagnetic properties of La 0.65 Ca 0.35 MnO 3 films with a thickness of 0.2 μm on Pb 2.9 Ba 0.05 Sr 0.05 (Zr 0.4 Ti 0.6 )O 3 ferroelectric ceramics substrates have been investigated. We have discovered the monotonic irreversible increase of the film resistance by 3-5 time of value during several hours after multiple inversion of substrate polarization. The long-time relaxation (LTR) of film resistance is explained by dielecrtrization of film intercrystallite boundaries as a result of oxygen redistribution under action of inhomogeneous mechanical stress. In addition, the LTR of resistance of La 0.8 Sr 0.2 MnO 3 and La 0.6 Sr 0.2 Mn 1.2 O 3 ceramic samples has been investigated under action of different kind of mechanical stress: stretch, compression and hydrostatic press. Time dependence of resistance is described by R 0 +ΔRexp(-t/τ). The magnitude of LTR is 5-10 time greater then fast variation of resistance under action of stress. The sign of ΔR is dependent on the kind of stress. The time constant (τ) has the value of 3-9 hours. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Decatropis bicolor (Zucc.) Radlk essential oil induces apoptosis of the MDA-MB-231 breast cancer cell line.

Science.gov (United States)

Estanislao Gómez, C C; Aquino Carreño, A; Pérez Ishiwara, D G; San Martín Martínez, E; Morales López, J; Pérez Hernández, N; Gómez García, M C

2016-08-05

Decatropis bicolor (Zucc.)Radlk is a plant that has been traditionally used for the treatment of breast cancer in some communities of Mexico. So, the aim of this study was to determine the cytotoxic and apoptotic effect of the essential oil of Decatropis bicolor against breast cancer cell line, MDA-MB-231. The essential oil obtained from hydrodestillation of leaves of Decatropis bicolor was studied for its biological activity against breast cancer cells MDA-MB-231 by MTT assay, Hematoxylin-eosin stain, Annexin V-FITC, TUNEL and western blot assays and for its chemical composition by GC-MS. The results showed a relevant cytotoxic effect of the essential oil towards MDA-MB-231 cells in a dose- and time- dependent manner, with an IC50 of 53.81 ± 1.691 μg/ml but not in the epithelial mammary cell line MCF10A (207.51 ± 3.26 μg/ml). Morphological examination displayed apoptotic characteristics in the treated cells like cell size reduction, membrane blebbing and apoptotic bodies. In addition, the apoptotic rate significantly increased as well as DNA fragmentation and western blot analysis revealed that the essential oil induced apoptosis in the MDA-MB-231 cells via intrinsic pathways due to the activation of Bax, caspases 9 and 3. Phytochemical analysis of the Decatropis bicolor essential oil showed the presence of twenty-three compounds. Major components of the oil were 1,5-cyclooctadiene,3-(methyl-2)propenyl (18.38 %), β-terpineol (8.16 %) and 1-(3-methyl-cyclopent-2-enyl)-cyclohexene (6.12 %). This study suggests that essential oil of Decatropis bicolor has a potential cytotoxic and antitumoral effect against breast cancer cells, with the presence of potential bioactive compounds. Our results contribute to the validation of the anticancer activity of the plant in Mexican traditional medicine.

Moessbauer Study of the Ni/Ca0.8Sr0.2Ti1-xFexO3-α Catalyst System for Partial Oxidation of Methane to Synthesis Gas

International Nuclear Information System (INIS)

Homonnay, Z.; Nomura, K.; Hamakawa, S.; Hayakawa, T.; Juhasz, G.; Kuzmann, E.; Vertes, A.

2002-01-01

The Ni/Ca 0.8 Sr 0.2 TiO 3 catalyst system prepared by the citrate method shows high activity in partial oxidation of methane to synthesis gas. It is assumed that the interaction of Ni with the perovskite lattice may be responsible for the increased catalytic activity. 1% 57 Fe dopant substituted for Ti was used in order to see if the presence of Ni has any perturbation effect on the structure of the perovskite. One may expect systematic changes in the Moessbauer parameters of the substitutional Fe impurity as a function of the NiO content if the bulk properties of the perovskite are affected. Samples with different Ni/Ca 0.8 Sr 0.2 Ti 0.99 57 Fe 0.01 O 3-α ratios from 0:1 to 1:1, and others having Fe substitutions for Ti up to 30%, all prepared by the citrate method, have been investigated. The Moessbauer spectra contained doublets of paramagnetic Fe 3+ and Fe 4+ species as well as paramagnetically relaxed Fe 3+ . These species were assigned to the bulk perovskite, the perovskite surface and the NiO/perovskite interface. The perturbation of the perovskite structure by Ni could not be verified.

Cytotoxic effect of sanguiin H-6 on MCF-7 and MDA-MB-231 human breast carcinoma cells.

Science.gov (United States)

Park, Eun-Ji; Lee, Dahae; Baek, Seon-Eun; Kim, Ki Hyun; Kang, Ki Sung; Jang, Tae Su; Lee, Hye Lim; Song, Ji Hoon; Yoo, Jeong-Eun

2017-09-15

Sanguiin H-6 is a dimer of casuarictin linked by a bond between the gallic acid residue and one of the hexahydroxydiphenic acid units. It is an effective compound extracted from Rubus coreanus. It has an anticancer effect against several human cancer cells; however, its effect on breast cancer cells has not been clearly demonstrated. Thus, we aimed to investigate the anticancer effect and mechanism of action of sanguiin H-6 against two human breast carcinoma cell lines (MCF-7 and MDA-MB-231). We found that sanguiin H-6 significantly reduced cell viability in a concentration-dependent manner. It also increased the rates at which MCF-7 and MDA-MB-231 cells underwent apoptosis. Furthermore, sanguiin H-6 induced the cleavage of caspase-8, caspase-3, and poly(ADP-ribose) polymerase, which resulted in apoptosis. However, cleavage of caspase-9 was only detectable in MCF-7 cells. In addition, sanguiin H-6 increased the ratio of Bax to Bcl-2 in both MCF-7 and MDA-MB-231 cells. These findings suggest that sanguiin H-6 is a potent therapeutic agent against breast cancer cells. In addition, it exerts its anticancer effect in an estrogen-receptor-independent manner. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study on Dy0.45Ba0.05Sr0.5Co0.8Fe0.2O3-δ-Ce0.85Gd0.15O1.95 composite cathode material for intermediate temperature solid oxide fuel cell

Science.gov (United States)

Kautkar, Pranay R.; Acharya, Smita A.

2018-05-01

xDy0.45Ba0.05Sr0.5Co0.8Fe0.2O3-δ - xCe0.85Gd0.15O1.95 (x = 50 %) composite cathode supported on Ce0.85Gd0.15O1.95 (GDC15) electrolyte are studied for applications in IT-SOFCs. Results attribute that Dy0.45Ba0.05Sr0.5Co0.8Fe0.2O3-δ material is chemically compatible with Ce0.85Gd0.15O1.95 (GDC15). Rietveld refined X-ray diffraction patterns notify orthorhombic (space group:Pbnm) symmetry for Dy0.45 Ba0.05Sr0.5Co0.8Fe0.2O3-δ and fluorite type structure (space group: Fm-3m) symmetry for GDC15. The polarization resistance (Rp) of composite cathode reduces to the minimum value of 1.35 Ω cm2 at 650 °C in air. Area specific resistance (ASR) of composite cathode has found 0.67 Ω.cm2 at 650°C respectively. Result shows that the surface diffusion of the dissociative adsorbed oxygen at electrode/electrolyte interface on the composite cathode.

A two-site immunoradiometric assay for the MB isoenzyme of creatine kinase

International Nuclear Information System (INIS)

Willson, V.J.C.; Jones, H.M.; Thompson, R.J.

1981-01-01

A two-site immunoradiometric assay for myocardial creatine kinase MB isoenzyme is described. The method utilizes immobilized anti-human creatine kinase BB antibodies and 125 I-labelled anti-human creatine kinase MM antibodies and can specifically detect creatine kinase MB in the presence of approximately 1000-fold excess of creatine kinase MM or BB. Native kinase MB prepared from human heart and creatine kinase MB prepared by hybridisation of purified human creatine kinase MM and creatine kinase BB appeared to react identically in the assay. Serum estimations on patients with suspected myocardial infarction correlated with the presence of MB band on electrophoresis but preliminary results suggest that the two-site immunoradiometric assay may be more sensitive. (Auth.)

Ziyuglycoside I Inhibits the Proliferation of MDA-MB-231 Breast Carcinoma Cells through Inducing p53-Mediated G2/M Cell Cycle Arrest and Intrinsic/Extrinsic Apoptosis.

Science.gov (United States)

Zhu, Xue; Wang, Ke; Zhang, Kai; Zhang, Ting; Yin, Yongxiang; Xu, Fei

2016-11-22

Due to the aggressive clinical behavior, poor outcome, and lack of effective specific targeted therapies, triple-negative breast cancer (TNBC) has currently been recognized as one of the most malignant types of tumors. In the present study, we investigated the cytotoxic effect of ziyuglycoside I, one of the major components extracted from Chinese anti-tumor herbal Radix Sanguisorbae , on the TNBC cell line MDA-MB-231. The underlying molecular mechanism of the cytotoxic effect ziyuglycoside I on MDA-MB-231 cells was investigated with cell viability assay, flow cytometric analysis and Western blot. Compared to normal mammary gland Hs 578Bst cells, treatment of ziyuglycoside I resulted in a significant growth inhibitory effect on MDA-MB-231 cells. Ziyuglycoside I induced the G2/M phase arrest and apoptosis of MDA-MB-231 cells in a dose-dependent manner. These effects were found to be partially mediated through the up-regulation of p53 and p21 WAF1 , elevated Bax/Bcl-2 ratio, and the activation of both intrinsic (mitochondrial-initiated) and extrinsic (Fas/FasL-initiated) apoptotic pathways. Furthermore, the p53 specific siRNA attenuated these effects. Our study suggested that ziyuglycoside I-triggered MDA-MB-231 cell cycle arrest and apoptosis were probably mediated by p53. This suggests that ziyuglycoside I might be a potential drug candidate for treating TNBC.

The crystal structure of ramdohrite Pb_5.9Fe_0.1Mn_0.1In_0.1Cd_0.2Ag_2.8Sb_10.8S₂₄

DEFF Research Database (Denmark)

Makovicky, Emil; Mumme, William G.; Gable, Robert W.

2013-01-01

The crystal structure of ramdohrite, Pb5.9Fe0.1Mn0.1In0.1Cd0.2Ag2.8Sb10.8S24, from the Chocaya mine, Potosí, Bolivia, determined by Makovicky and Mumme from film data in 1983, was refined from single-crystal diffractometer data to the R value 0.060, based on 5230 reflections [I > 2σ(I)] from...... a twinned crystal. Lattice parameters are a = 8.7348(3), b = 13.0543(4), c = 19.3117(6) Å, and β = 90.179(2)°, space group P21/n. Two bicapped trigonal prismatic sites of lead bridge and unite adjacent (311)PbS slabs. These slabs contain five distinct coordination pyramids of Sb with trapezoidal cross...... sections, a mixed and disordered Sb-Ag-Cd-(Pb) site, refined as 0.39 Sb + 0.61 Ag, a pure Ag site with a very open, irregular tetrahedral coordination, and an octahedral site occupied by Pb. The (311)PbS slabs contain large lone electron pair micelles formed by four distinct antimony sites in alternation...

The histone methyltransferase SET8 is required for S-phase progression

DEFF Research Database (Denmark)

Jørgensen, Stine; Elvers, Ingegerd; Trelle, Morten Beck

2008-01-01

Chromatin structure and function is influenced by histone posttranslational modifications. SET8 (also known as PR-Set7 and SETD8) is a histone methyltransferase that monomethylates histonfe H4-K20. However, a function for SET8 in mammalian cell proliferation has not been determined. We show...

Magnetic properties and superconducting-fluctuation diamagnetism above Tc in Bi2-xPbxSr2CaCu2O8+δ (x=0.0, 0.1, 0.2, 0.3, 0.5) and

International Nuclear Information System (INIS)

Lee, W.C.; Cho, J.H.; Johnston, D.C.

1991-01-01

The magnetic susceptibilities χ(T) of the title compounds above and below T c are reported. For the Bi 2-x Pb x Sr 2 CaCu 2 O 8+δ (Bi 2:2:1:2) system, optimization of the phase purity and superconducting properties is found between x=0.2 and 0.3. The χ(T) data for these Bi 2:2:1:2 and for the two Bi 2:2:2:3 samples increase monotonically with temperature from T c up to at least 400 K, exhibiting strong negative curvature below ∼200 K. From theoretical fits to the data in the two-dimensional regime above T c using the static Lawrence-Doniach model as modified by Klemm, we conclude that the negative curvature in χ(T) for each sample arises from superconducting-fluctuation diamagnetism (SFD). The data are thus consistent with a superconducting order parameter of s-wave symmetry. From the fits to the data, the Ginzburg-Landau coherence lengths in the CuO 2 planes were obtained and found to be ξ ab (0)=20.4(2) A for Bi 2:2:1:2 and 11.8(4) A for Bi 2:2:2:3. The value for Bi 2:2:1:2 is comparable to those calculated from upper critical magnetic-field data for this compound (23.5--27.1 A). Our ξ ab (0) values for Bi 2:2:1:2 and Bi 2:2:2:3 are also comparable with that (13.6 A) found from our previous similar analysis of the SFD in YBa 2 Cu 3 O 7 . The possible role of the bridging oxygens out of the CuO 2 plane in Bi 2:2:2:3 and the influence of the dynamics in the fits to the SFD in the Bi-based compounds remain to be addressed

MeB/sub 5/O/sub 8/(Me-Li, Na, K, NH/sub 4/)-H/sub 2/NCONHCOCH/sub 3/-H/sub 2/O system at 25 deg C

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Fedorov, Yu A; Molodkin, A K; Tsekhanskij, R S

1986-06-01

Using the methods of isothermal solubility, densi- and refractometry, systems MB/sub 5/O/sub 8/ (M-Li, Na, K, NH/sub 4/)-acetylcarbamide - H/sub 2/O at 25 deg C have been studied. It is ascertained, that the systems investigated are of simple eutonic type.

In situ synchrotron X-ray diffraction of ferroelastic La0.8Ca0.2CoO3 ceramics during uniaxial compression

International Nuclear Information System (INIS)

Vullum, Per Erik; Mastin, Johann; Wright, Jonathan; Einarsrud, Mari-Ann; Holmestad, Randi; Grande, Tor

2006-01-01

Uniaxial compression of rhombohedral La 0.8 Ca 0.2 CoO 3 ceramics has been studied in situ using synchrotron X-ray diffraction. The intensities of Bragg reflections parallel and perpendicular to the stress field were simultaneously detected as a function of the stress. Reorientation of ferroelastic domains due to the uniaxial stress was demonstrated. With increasing stress the volume fraction of domains with the hexagonal c-axis parallel to the stress axis increased at the expense of domains with the c-axis perpendicular to the stress axis. The strain in the polycrystalline materials evolved unevenly with increasing stress due to crystallographic anisotropy. In energetically favourable domains with the c-axis parallel to the stress axis, the rhombohedral distortion from cubic symmetry increased, while the crystal structure became closer to cubic in domains with the c-axis perpendicular to the stress. Successive compression/decompression cycles to higher maximum stress resulted in a higher volume fraction of reoriented domains both at maximum stress and after decompression

Buckling Test Results and Preliminary Test and Analysis Correlation from the 8-Foot-Diameter Orthogrid-Stiffened Cylinder Test Article TA02

Science.gov (United States)

Hilburger, Mark W.; Waters, W. Allen, Jr.; Haynie, Waddy T.; Thornburgh, Robert P

2017-01-01

Results from the testing of cylinder test article SBKF-P2-CYL-TA02 (referred to herein as TA02) are presented. TA02 is an 8-foot-diameter (96-inches), 78.0-inch-long, aluminum-lithium (Al-Li), orthogrid-stiffened cylindrical shell similar to those used in current state-of-the-art launch-vehicle structures and was designed to exhibit global buckling when subjected to combined compression and bending loads. The testing was conducted at the Marshall Space Flight Center (MSFC), February 3-6, 2009, in support of the Shell Buckling Knockdown Factor Project (SBKF). The test was used to verify the performance of a newly constructed buckling test facility at MSFC and to verify the test article design and analysis approach used by the SBKF researchers.

Geometry of (0,2) Landau-Ginzburg orbifolds

International Nuclear Information System (INIS)

Kawai, Toshiya; Mohri, Kenji

1994-01-01

Several aspects of (0,2) Landau-Ginzburg orbifolds are investigated. Especially the elliptic genera are computed in general and, for a class of models recently invented by Distler and Kachru, they are compared with the ones from (0,2) sigma models. Our formalism gives an easy way to calculate the generation numbers for lots of Distler-Kachru models even if they are based on singular Calabi-Yau spaces. We also make some general remarks on the Born-Oppenheimer calculation of the ground states elucidating its mathematical meaning in the untwisted sector. For Distler-Kachru models based on non-singular Calabi-Yau spaces we show that there exist ''residue'' type formulas of the elliptic genera as well. ((orig.))

Crystal structure and magnetic properties of Bi0.8A0.2FeO3 (A = La, Ca, Sr, Ba multiferroics using neutron diffraction and Mossbauer spectroscopy

Directory of Open Access Journals (Sweden)

Manisha Rangi

2014-08-01

Full Text Available Bi0.8A0.2FeO3 (A = La, Ca, Sr, Ba multiferroics were studied using x-ray, neutron diffraction and magnetization techniques. All the samples crystallized in rhombohedral structure with space group R3c. The compounds exhibit antiferromagnetic (AFM ordering at 300 K and no evidence of further structural or magnetic transition was observed on lowering of temperature below it. The magnetic structure of these substituted compounds are found to be collinear G-type AFM structure as against the non collinear incommensurate magnetic structure reported in the case of parent compound. The moments on Fe at 6 K are aligned along the a-axis in the case of Ca-doped sample. With increase in the ionic radii of dopant, the moments are found to be aligned in the ac plane and the angle of tilt away from the a-axis increases. The observed change in the magnetic structure with substitution is attributed to the intrinsic structural distortion as evidenced by the change in the bond angle (Fe-O-Fe and bond distances (Bi-O, Fe-O. It has been found that heterovalent substitution A2+ results in the formation of oxygen vacancies in the parent lattices as the possibility of Fe4+ ruled out by Mössbauer spectra recorded at room temperature. Higher value of remnant magnetization (0.4187 emu/g and coercivity (4.7554kOe is observed in Bi0.8Ba0.2FeO3 sample in comparison to other substituted samples revealing a strong correlation between ionic radii and magnetization.

Requirement of carbon dioxide for initial growth of facultative methylotroph, Acidomonas methanolica MB58.

Science.gov (United States)

Mitsui, Ryoji; Katayama, Hiroko; Tanaka, Mitsuo

2015-07-01

The facultative methylotrophic bacterium Acidomonas methanolica MB58 can utilize C1 compounds via the ribulose monophosphate pathway. A large gene cluster comprising three components related to C1 metabolism was found in the genome. From upstream, the first was an mxa cluster encoding proteins for oxidation of methanol to formaldehyde; the second was the rmp cluster encoding enzymes for formaldehyde fixation; and the third was the cbb gene cluster encoding proteins for carbon dioxide (CO2) fixation. Examination of CO2 requirements for growth of A. methanolica MB58 cells demonstrated that it did not grow on any carbon source under CO2-free conditions. Measurement of ribulose-1,5-bisphosphate carboxylase activity and RT-PCR analysis demonstrated enzymatic activity was detected in A. methanolica MB58 at growth phase, regardless of carbon sources. However, methanol dehydrogenase and 3-hexlose-6-phosphate synthase expression was regulated by methanol or formaldehyde; it were detected during growth and apparently differed from ribulose-1,5-bisphosphate carboxylase expression. These results suggested that A. methanolica MB58 may be initially dependent on autotrophic growth and that carbon assimilation was subsequently coupled with the ribulose monophosphate pathway at early- to mid-log phases during methylotrophic growth. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Preparation of cobalt-zinc ferrite (Co0.8Zn0.2Fe2O4) nanopowder via combustion method and investigation of its magnetic properties

International Nuclear Information System (INIS)

Yousefi, M.H.; Manouchehri, S.; Arab, A.; Mozaffari, M.; Amiri, Gh. R.; Amighian, J.

2010-01-01

Research highlights: → Cobalt-zinc ferrite was prepared by combustion method. → Properties of the sample were characterized by several techniques. → Curie temperature was determined to be 350 o C. -- Abstract: Cobalt-zinc ferrite (Co 0.8 Zn 0.2 Fe 2 O 4 ) was prepared by combustion method, using cobalt, zinc and iron nitrates. The crystallinity of the as-burnt powder was developed by annealing at 700 o C. Crystalline phase was investigated by XRD. Using Williamson-Hall method, the average crystallite sizes for nanoparticles were determined to be about 27 nm before and 37 nm after annealing, and residual stresses for annealed particles were omitted. The morphology of the annealed sample was investigated by TEM and the mean particle size was determined to be about 30 nm. The final stoichiometry of the sample after annealing showed good agreement with the initial stoichiometry using atomic absorption spectrometry. Magnetic properties of the annealed sample such as saturation magnetization, remanence magnetization, and coercivity measured at room temperature were 70 emu/g, 14 emu/g, and 270 Oe, respectively. The Curie temperature of the sample was determined to be 350 o C using AC-susceptibility technique.

Ultra high resolution imaging of the human head at 8 tesla: 2K x 2K for Y2K.

Science.gov (United States)

Robitaille, P M; Abduljalil, A M; Kangarlu, A

2000-01-01

To acquire ultra high resolution MRI images of the human brain at 8 Tesla within a clinically acceptable time frame. Gradient echo images were acquired from the human head of normal subjects using a transverse electromagnetic resonator operating in quadrature and tuned to 340 MHz. In each study, a group of six images was obtained containing a total of 208 MB of unprocessed information. Typical acquisition parameters were as follows: matrix = 2,000 x 2,000, field of view = 20 cm, slice thickness = 2 mm, number of excitations (NEX) = 1, flip angle = 45 degrees, TR = 750 ms, TE = 17 ms, receiver bandwidth = 69.4 kHz. This resulted in a total scan time of 23 minutes, an in-plane resolution of 100 microm, and a pixel volume of 0.02 mm3. The ultra high resolution images acquired in this study represent more than a 50-fold increase in in-plane resolution relative to conventional 256 x 256 images obtained with a 20 cm field of view and a 5 mm slice thickness. Nonetheless, the ultra high resolution images could be acquired both with adequate image quality and signal to noise. They revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. The elevated signal-to-noise ratio observed in ultra high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the histological level under in vivo conditions. However, brain motion is likely to degrade the useful resolution. This situation may be remedied in part with cardiac gating. Nonetheless, these images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods.

Δ9-THC modulation of fatty acid 2-hydroxylase (FA2H) gene expression: Possible involvement of induced levels of PPARα in MDA-MB-231 breast cancer cells

International Nuclear Information System (INIS)

Takeda, Shuso; Ikeda, Eriko; Su, Shengzhong; Harada, Mari; Okazaki, Hiroyuki; Yoshioka, Yasushi; Nishimura, Hajime; Ishii, Hiroyuki; Kakizoe, Kazuhiro; Taniguchi, Aya; Tokuyasu, Miki; Himeno, Taichi; Watanabe, Kazuhito; Omiecinski, Curtis J.; Aramaki, Hironori

2014-01-01

We recently reported that Δ 9 -tetrahydrocannabinol (Δ 9 -THC), a major cannabinoid component in Cannabis Sativa (marijuana), significantly stimulated the expression of fatty acid 2-hydroxylase (FA2H) in human breast cancer MDA-MB-231 cells. Peroxisome proliferator-activated receptor α (PPARα) was previously implicated in this induction. However, the mechanisms mediating this induction have not been elucidated in detail. We performed a DNA microarray analysis of Δ 9 -THC-treated samples and showed the selective up-regulation of the PPARα isoform coupled with the induction of FA2H over the other isoforms (β and γ). Δ 9 -THC itself had no binding/activation potential to/on PPARα, and palmitic acid (PA), a PPARα ligand, exhibited no stimulatory effects on FA2H in MDA-MB-231 cells; thus, we hypothesized that the levels of PPARα induced were involved in the Δ 9 -THC-mediated increase in FA2H. In support of this hypothesis, we herein demonstrated that; (i) Δ 9 -THC activated the basal transcriptional activity of PPARα in a concentration-dependent manner, (ii) the concomitant up-regulation of PPARα/FA2H was caused by Δ 9 -THC, (iii) PA could activate PPARα after the PPARα expression plasmid was introduced, and (iv) the Δ 9 -THC-induced up-regulation of FA2H was further stimulated by the co-treatment with L-663,536 (a known PPARα inducer). Taken together, these results support the concept that the induced levels of PPARα may be involved in the Δ 9 -THC up-regulation of FA2H in MDA-MB-231 cells

Δ(9)-THC modulation of fatty acid 2-hydroxylase (FA2H) gene expression: possible involvement of induced levels of PPARα in MDA-MB-231 breast cancer cells.

Science.gov (United States)

Takeda, Shuso; Ikeda, Eriko; Su, Shengzhong; Harada, Mari; Okazaki, Hiroyuki; Yoshioka, Yasushi; Nishimura, Hajime; Ishii, Hiroyuki; Kakizoe, Kazuhiro; Taniguchi, Aya; Tokuyasu, Miki; Himeno, Taichi; Watanabe, Kazuhito; Omiecinski, Curtis J; Aramaki, Hironori

2014-12-04

We recently reported that Δ(9)-tetrahydrocannabinol (Δ(9)-THC), a major cannabinoid component in Cannabis Sativa (marijuana), significantly stimulated the expression of fatty acid 2-hydroxylase (FA2H) in human breast cancer MDA-MB-231 cells. Peroxisome proliferator-activated receptor α (PPARα) was previously implicated in this induction. However, the mechanisms mediating this induction have not been elucidated in detail. We performed a DNA microarray analysis of Δ(9)-THC-treated samples and showed the selective up-regulation of the PPARα isoform coupled with the induction of FA2H over the other isoforms (β and γ). Δ(9)-THC itself had no binding/activation potential to/on PPARα, and palmitic acid (PA), a PPARα ligand, exhibited no stimulatory effects on FA2H in MDA-MB-231 cells; thus, we hypothesized that the levels of PPARα induced were involved in the Δ(9)-THC-mediated increase in FA2H. In support of this hypothesis, we herein demonstrated that; (i) Δ(9)-THC activated the basal transcriptional activity of PPARα in a concentration-dependent manner, (ii) the concomitant up-regulation of PPARα/FA2H was caused by Δ(9)-THC, (iii) PA could activate PPARα after the PPARα expression plasmid was introduced, and (iv) the Δ(9)-THC-induced up-regulation of FA2H was further stimulated by the co-treatment with L-663,536 (a known PPARα inducer). Taken together, these results support the concept that the induced levels of PPARα may be involved in the Δ(9)-THC up-regulation of FA2H in MDA-MB-231 cells. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Dielectric and magnetic properties of xCoFe{sub 2}O{sub 4}–(1 − x)[0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3}] composites

Energy Technology Data Exchange (ETDEWEB)

Rani, Jyoti [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Yadav, K.L., E-mail: klyadav35@yahoo.com [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Prakash, Satya [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

2014-12-15

Highlights: • Spinel–perovskite xCoFe{sub 2}O{sub 4}–(1 − x)(0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3}) composites have been synthesized by solid state reaction method. • Two anomalies in dielectric constant have been identified, and the composites show relaxor behaviour. • The magnetic properties of the composites improve with increasing concentration of CoFe{sub 2}O{sub 4}. • Enhanced magnetodielectric effect is found, and magnetoelectric coupling has been confirmed by Δϵ ∼ γM{sup 2} relation. • Optical band gap energy of these composites has been reported for the first time. - Abstract: xCoFe{sub 2}O{sub 4}–(1 − x)(0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3}) composites with x = 0.1, 0.2, 0.3 and 0.4 have been synthesized by solid state reaction method. X-ray diffraction analysis and field emission secondary electron microscopy have been used for structural and morphological analysis, respectively. The spinel CoFe{sub 2}O{sub 4} and perovskite 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} phase could be identified in the composites. Two anomalies in dielectric constant have been identified: first one is close to ferroelectric to paraelectric phase transition of 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} ceramic and the other lies near the magnetic transition temperature of CoFe{sub 2}O{sub 4}. There is an increase in magnetocapacitance and saturation magnetization of the composites at room temperature with increase in CoFe{sub 2}O{sub 4} content. The magnetoelectric coupling coefficient (γ) was approximated by Δϵ ∼ γM{sup 2} relation. The optical band gap energy of the composites decreases with increase in CoFe{sub 2}O{sub 4} content.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

PELATIHAN BERJALAN DI ATAS BALOK LURUS SEJAUH 8 METER 5 REPETISI 4 SET LEBIH BAIK DARIPADA 4 REPETISI 5 SET TERHADAP KESEIMBANGAN TUBUH MAHASISWA FAKULTAS PENDIDIKAN OLAHRAGA DAN KESEHATAN IKIP PGRI BALI

Directory of Open Access Journals (Sweden)

I G P Ngurah Adi Santika

2015-01-01

Full Text Available The Body Balance of students of the Faculty of Sport Education and Health PGRI Bali tend to decrease. This is supported by preliminary data from the body balance, that the students are in the norm level of balance. The purpose of this study was to determine the effect of walking training on a straight beam 8 m x 10 cm x 30 cm 4 sets of 5 reps increasing student body balance Faculty of Sport Education and Healt Students IKIP PGRI Bali and to investigate the training walk on a straight beam 8 m x 10 cm x 30 cm 4 sets of 5 reps improve body balance is bigger than 4 repetitions 5 sets of students of Faculty of Sport Educatoin and Healt Student IKIP PGRI Bali. This study used a pretest-posttest randomized control group design. A total of 22 students aged 18-23 years were selected as members of the sample were divided into 2 groups. Group I was given a training walk on a straight beam as far as 8 feet 5 repetitions 4 sets and a Group II are trained to walk on a straight block as far as 8 feets 4 repetitions 5 sets. Training was given 4 times a week for 6 weeks. Balancing is measured before and after training use stork balance test. T-test Paired is used to determine the balance mean difference in the balance of each group before and after treatment with a significance level of 0,05, t-independent test to determine the increasing of the body balance. The results showed an increase in of body balance of the group I and group II. The results of test paired in group I the first data is 20,02±2,52 seconds increased 40,10±3,80 seconds in group II the first data is 21,47±5,08 seconds increased 34,59±5,47 seconds by significance level of 0,05 is significantly different. Test Paired results indicate a difference of the intreasing of balance of the group I and group II. Independent test results in group I was 20,08 seconds 50,07% and in group II was 13,12 seconds 37,93%. Based on these results we can conclude that training walk on a straight block as far as

Anion Redox Chemistry in the Cobalt Free 3d Transition Metal Oxide Intercalation Electrode Li[Li0.2Ni0.2Mn0.6]O2.

Science.gov (United States)

Luo, Kun; Roberts, Matthew R; Guerrini, Niccoló; Tapia-Ruiz, Nuria; Hao, Rong; Massel, Felix; Pickup, David M; Ramos, Silvia; Liu, Yi-Sheng; Guo, Jinghua; Chadwick, Alan V; Duda, Laurent C; Bruce, Peter G

2016-09-07

Conventional intercalation cathodes for lithium batteries store charge in redox reactions associated with the transition metal cations, e.g., Mn(3+/4+) in LiMn2O4, and this limits the energy storage of Li-ion batteries. Compounds such as Li[Li0.2Ni0.2Mn0.6]O2 exhibit a capacity to store charge in excess of the transition metal redox reactions. The additional capacity occurs at and above 4.5 V versus Li(+)/Li. The capacity at 4.5 V is dominated by oxidation of the O(2-) anions accounting for ∼0.43 e(-)/formula unit, with an additional 0.06 e(-)/formula unit being associated with O loss from the lattice. In contrast, the capacity above 4.5 V is mainly O loss, ∼0.08 e(-)/formula. The O redox reaction involves the formation of localized hole states on O during charge, which are located on O coordinated by (Mn(4+)/Li(+)). The results have been obtained by combining operando electrochemical mass spec on (18)O labeled Li[Li0.2Ni0.2Mn0.6]O2 with XANES, soft X-ray spectroscopy, resonant inelastic X-ray spectroscopy, and Raman spectroscopy. Finally the general features of O redox are described with discussion about the role of comparatively ionic (less covalent) 3d metal-oxygen interaction on anion redox in lithium rich cathode materials.

Low-loss optical waveguides made with molecular beam epitaxial In(0.012)Ga(0.988)As and In(0.2)Ga(0.8)As-GaAs superlattices

Science.gov (United States)

Das, U.; Bhattacharya, P. K.; Dhar, S.

1986-01-01

Low-loss optical guiding in In-doped GaAs is demonstrated for the first time. Ridge waveguides are made with single In(0.012)Ga(0.988)As ternary layers and In(0.2)Ga(0.8)As-GaAs superlattices. Attenuation constants of about 1.3 dB/cm are measured and the principal loss mechanism is identified to be scattering at the ridge walls. It is expected that improved fabrication techniques will lead to guides with attenuation less than or equal to 0.5 dB/cm.

Demonstration of 575-Mb/s downlink and 225-Mb/s uplink bi-directional SCM-WDM visible light communication using RGB LED and phosphor-based LED.

Science.gov (United States)

Wang, Yuanquan; Wang, Yiguang; Chi, Nan; Yu, Jianjun; Shang, Huiliang

2013-01-14

We propose and experimentally demonstrate a novel full-duplex bi-directional subcarrier multiplexing (SCM)-wavelength division multiplexing (WDM) visible light communication (VLC) system based on commercially available red-green-blue (RGB) light emitting diode (LED) and phosphor-based LED (P-LED) with 575-Mb/s downstream and 225-Mb/s upstream transmission, employing various modulation orders of quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM). For the downlink, red and green colors/wavelengths are assigned to carry useful information, while blue chip is just kept lighting to maintain the white color illumination, and for the uplink, the low-cost P-LED is implemented. In this demonstration, pre-equalization and post-equalization are also adopted to compensate the severe frequency response of LEDs. Using this scheme, 4-user downlink and 1-user uplink transmission can be achieved. Furthermore, it can support more users by adjusting the bandwidth of each sub-channel. Bit error rates (BERs) of all links are below pre-forward-error-correction (pre-FEC) threshold of 3.8x 10(-3) after 66-cm free-space delivery. The results show that this scheme has great potential in the practical VLC system.

Photoionization from the 6p 2P3/2 state of neutral cesium

International Nuclear Information System (INIS)

Haq, S. U.; Nadeem, Ali

2010-01-01

We report the photoionization studies of cesium from the 6p 2 P 3/2 excited state to measure the photoionization cross section at and above the first ionization threshold, oscillator strength of the highly excited transitions, and extension in the Rydberg series. The photoionization cross section at the first ionization threshold is measured as 25 (4) Mb and at excess energies 0.02, 0.04, 0.07, and 0.09 eV as 21, 19, 17, and 16 Mb, respectively. Oscillator strength of the 6p 2 P 3/2 → nd 2 D 5/2 (23 ≤ n ≤ 60) Rydberg transitions has been extracted utilizing the threshold value of photoionization cross section and the recorded nd 2 D 5/2 photoionization spectra.

Ablation-resistant carbide Zr0.8Ti0.2C0.74B0.26 for oxidizing environments up to 3,000 °C

Science.gov (United States)

Zeng, Yi; Wang, Dini; Xiong, Xiang; Zhang, Xun; Withers, Philip J.; Sun, Wei; Smith, Matthew; Bai, Mingwen; Xiao, Ping

2017-06-01

Ultra-high temperature ceramics are desirable for applications in the hypersonic vehicle, rockets, re-entry spacecraft and defence sectors, but few materials can currently satisfy the associated high temperature ablation requirements. Here we design and fabricate a carbide (Zr0.8Ti0.2C0.74B0.26) coating by reactive melt infiltration and pack cementation onto a C/C composite. It displays superior ablation resistance at temperatures from 2,000-3,000 °C, compared to existing ultra-high temperature ceramics (for example, a rate of material loss over 12 times better than conventional zirconium carbide at 2,500 °C). The carbide is a substitutional solid solution of Zr-Ti containing carbon vacancies that are randomly occupied by boron atoms. The sealing ability of the ceramic's oxides, slow oxygen diffusion and a dense and gradient distribution of ceramic result in much slower loss of protective oxide layers formed during ablation than other ceramic systems, leading to the superior ablation resistance.

[Knock-down of BCL11A expression in breast cancer cells promotes MDA-MB-231 cell apoptosis].

Science.gov (United States)

Li, Hongli; Gui, Chen; Yan, Lijun

2016-11-01

Objective To detect the expression and pathological significance of B-cell CLL/lymphoma 11A (BCL11A) in breast cancer and investigate the effect of its silencing on the apoptosis of human MDA-MB-231 breast cancer cells. MethodsImmunohistochemistry was used to detect the expression of BCL11A in 62 cases of human breast cancer tissues and 8 cases of normal tissues. We synthesized siRNA targeting BCL11A, and then siRNA was transfected into MDA-MB-231 cells. Forty-eight hours later, the suppression effect of siRNA on BCL11A was determined by quantitative real-time PCR and Western blotting. The apoptosis of MDA-MB-231 cells was detected by flow cytometry. Results The BCL11A protein was mainly expressed in cytoplasm. The expression level of BCL11A in breast cancer tissues was higher than that in paracancerous tissues. The expression had correlations with tumor grade, tumor stage, while it had no correlations with the patients' age and tumor size. BCL11A-siRNA significantly suppressed the expression of BCL11A mRNA and protein as compared with the control group. MDA-MB-231 cells transfected with BCL11A-siRNA had higher apoptosis rate compared with the control group. Conclusion The BCL11A protein is highly expressed in breast cancer and knock-down of BCL11A promotes the apoptosis of MDA-MB-231 cells.

40 CFR 52.02 - Introduction.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Introduction. 52.02 Section 52.02 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS General Provisions § 52.02 Introduction. (a) This part sets forth the...

MANAGEMENT BOARD OF 22/02/08 (MB114)

CERN Document Server

LHCC At the LHCC open meeting earlier in the week it was stated that the machine was now expected to be cold by June 15. CMS Progress The magnet had been leak and pressure tested; the cool-down had begun and should be complete in mid-March. The low current test was foreseen for April. The Tracker testing and connecting was continuing. Crystals were mounted on two end-cap Dees and the order for the crystals for the 37th Supermodule was being placed. Functional tests of the software and computing infrastructure were being carried out. The release of CMSSW 2.0 was now scheduled for the first week of April. Physics preparation was focussing on start-up scenarios. The current objectives were to have CMS closed and ready for beam at the end of May, with the magnet on for a cosmic run at 4T by mid-June, while waiting for beam. By the middle of the year the full low luminosity detector should be ready and the collaboration ready for data. The zero-fault philosophy was being maintained, and the definitive closing...

Detection of genomic variation by selection of a 9 mb DNA region and high throughput sequencing.

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Sergey I Nikolaev

Full Text Available Detection of the rare polymorphisms and causative mutations of genetic diseases in a targeted genomic area has become a major goal in order to understand genomic and phenotypic variability. We have interrogated repeat-masked regions of 8.9 Mb on human chromosomes 21 (7.8 Mb and 7 (1.1 Mb from an individual from the International HapMap Project (NA12872. We have optimized a method of genomic selection for high throughput sequencing. Microarray-based selection and sequencing resulted in 260-fold enrichment, with 41% of reads mapping to the target region. 83% of SNPs in the targeted region had at least 4-fold sequence coverage and 54% at least 15-fold. When assaying HapMap SNPs in NA12872, our sequence genotypes are 91.3% concordant in regions with coverage > or = 4-fold, and 97.9% concordant in regions with coverage > or = 15-fold. About 81% of the SNPs recovered with both thresholds are listed in dbSNP. We observed that regions with low sequence coverage occur in close proximity to low-complexity DNA. Validation experiments using Sanger sequencing were performed for 46 SNPs with 15-20 fold coverage, with a confirmation rate of 96%, suggesting that DNA selection provides an accurate and cost-effective method for identifying rare genomic variants.

AB INITIO INVESTIGATION OF 12-CROWN-4 AND BENZO-12-CROWN-4 COMPLEXES WITH Li+, Na+, K+, Zn2+, Cd2+, AND Hg2+

Directory of Open Access Journals (Sweden)

Yahmin Yahmin

2010-06-01

Full Text Available The structure and binding energies of 12-crown-4 and benzo-12-crown-4 complexes with Li+, Na+, K+, Zn2+, Cd2+, and Hg2+were investigated with ab initio calculations using Hartree-Fock approximation and second-order perturbation theory. The basis set used in this study is lanl2mb. The structure optimization of cation-crown ether complexes was evaluated at HF/lanl2mb level of theory and interaction energy of the corresponding complexes was calculated at MP2/lanl2mb level of theory (MP2/lanl2mb//HF/lanl2mb. Interactions of the crown ethers and the cations were discussed in term of the structure parameter of crown ether. The binding energies of the complexes show that all complex formed from transition metal cations is more stable than the complexes formed from alkali metal cations.   Keywords: 12-crown-4, benzo-12-crown-4, alkali metals, transition metals

Electrochemical Characterization of La0.58Sr0.4Co0.2Fe0.8O3-δ Thin Film Electrodes Prepared by Pulsed Laser Deposition

DEFF Research Database (Denmark)

Plonczak, Pawel; Søgaard, Martin; Bieberle-Hütter, Anja

2012-01-01

Electrochemical properties of La0.58Sr0.4Co0.2Fe0.8O3-δ (LSCF) thin films with well defined microstructures have been investigated. Symmetrical cells were characterized by impedance spectroscopy in the temperature range from 625 to 750°C and the oxygen partial pressure, range from 10-2 to 1 atm...... have only an area specific resistance of 0.38 Ω cm2. It is shown that the polarization resistance of thin films is approximately proportional to the inverse of the surface area of the porous cathodes in the temperature regime 625 to 750°C. The activation energy of the surface oxygen exchange process...... depends on the thin film microstructure as it decreased from 2.4 eV for dense films to 1.6 eV for porous films....

Regional 500 mb heights and U.S. 1 000-500 mb thickness prior to the radiosonde era

Science.gov (United States)

Michaels, P. J.; Sappington, D. E.; Stooksbury, D. E.; Hayden, B. P.

1990-09-01

We developed a statistical model relating cyclone track eigenvectors over the U.S., southern Canada, and nearby oceans to a record of mean annual 500 mb heights. The length of the cyclone track record allowed us to calculate mean heights back to 1885. Use of mean annual surface pressure data allowed us to estimate the mean 1 000-500 mb thickness, which was related to mean annual temperature. This temperature calculation is unique in that it cannot suffer from urban or site bias. We find a warming of 1.5°C from the late 19th century to 1955, followed by a drop of 0.7° to 1980. By 1987, the calculated temperatures were 0.3° above the mean for 103 years of record. As an example of regional application, we examine results over the southwestern U.S.

WE-G-18C-02: Estimation of Optimal B-Value Set for Obtaining Apparent Diffusion Coefficient Free From Perfusion in Non-Small Cell Lung Cancer

Energy Technology Data Exchange (ETDEWEB)

Karki, K; Hugo, G; Ford, J; Saraiya, S; Weiss, E [Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States); Olsen, K; Groves, R [Radiology, Virginia Commonwealth University, Richmond, VA (United States)

2014-06-15

Purpose: Diffusion-weighted MRI (DW-MRI) is increasingly being investigated for radiotherapy planning and response assessment. Selection of a limited number of b-values in DW-MRI is important to keep geometrical variations low and imaging time short. We investigated various b-value sets to determine an optimal set for obtaining monoexponential apparent diffusion coefficient (ADC) close to perfusion-insensitive intravoxel incoherent motion (IVIM) model ADC (ADC_IVIM) in nonsmall cell lung cancer. Methods: Seven patients had 27 DW-MRI scans before and during radiotherapy in a 1.5T scanner. Respiratory triggering was applied to the echo-planar DW-MRI with TR=4500ms approximately, TE=74ms, pixel size=1.98X1.98mm{sub 2}, slice thickness=4–6mm and 7 axial slices. Diffusion gradients were applied to all three axes producing traceweighted images with eight b-values of 0–1000μs/μm{sup 2}. Monoexponential model ADC values using various b-value sets were compared to ADC_IVIM using all b-values. To compare the relative noise in ADC maps, intra-scan coefficient of variation (CV) of active tumor volumes was computed. Results: ADC_IVIM, perfusion coefficient and perfusion fraction for tumor volumes were in the range of 880-1622 μm{sup 2}/s, 8119-33834 μm{sup 2}/s and 0.104–0.349, respectively. ADC values using sets of 250, 800 and 1000; 250, 650 and 1000; and 250–1000μs/μm{sup 2} only were not significantly different from ADC_IVIM(p>0.05, paired t-test). Error in ADC values for 0–1000, 50–1000, 100–1000, 250–1000, 500–1000, and three b-value sets- 250, 500 and 1000; 250, 650 and 1000; and 250, 800 and 1000μs/μm{sup 2} were 15.0, 9.4, 5.6, 1.4, 11.7, 3.7, 2.0 and 0.2% relative to the reference-standard ADC_IVIM, respectively. Mean intrascan CV was 20.2, 20.9, 21.9, 24.9, 32.6, 25.8, 25.4 and 24.8%, respectively, whereas that for ADC_IVIM was 23.3%. Conclusion: ADC values of two 3 b-value sets

Properties of half metallic (Ba0.8Sr0.2)2-x La2x/3x/3FeMoO6 double perovskites

International Nuclear Information System (INIS)

Serrate, D.; De Teresa, J.M.; Blasco, J.; Morellon, L.; Ibarra, M.R.

2005-01-01

Previous work in (Ba 0.8 Sr 0.2 ) 2- x La x FeMoO 6 and Ba 1+ x Sr 1-3 x La 2 x FeMoO 6 have stated electron doping as the most important parameter in terms of T c enhancement. Here we report complementary structural, magnetic and transport properties, say a series where there is no doping and only structural parameters are changed: (Ba 0.8 Sr 0.2 ) 2- x La 2 x /3 x /3 FeMoO 6 . We propose a complete phase diagram where structural and bandfilling impact on the Curie temperature is clearly evidenced

Δ{sup 9}-THC modulation of fatty acid 2-hydroxylase (FA2H) gene expression: Possible involvement of induced levels of PPARα in MDA-MB-231 breast cancer cells

Energy Technology Data Exchange (ETDEWEB)

Takeda, Shuso [Department of Molecular Biology, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan); Laboratory of Xenobiotic Metabolism and Environmental Toxicology, Faculty of Pharmaceutical Sciences, Hiroshima International University (HIU), 5-1-1 Hiro-koshingai, Kure, Hiroshima 737-0112 (Japan); Ikeda, Eriko [Department of Molecular Biology, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan); Su, Shengzhong [Center for Molecular Toxicology and Carcinogenesis, 101 Life Sciences Building, Pennsylvania State University, University Park, PA 16802 (United States); Harada, Mari [Department of Molecular Biology, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan); Okazaki, Hiroyuki [Drug Innovation Research Center, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan); Yoshioka, Yasushi; Nishimura, Hajime; Ishii, Hiroyuki; Kakizoe, Kazuhiro; Taniguchi, Aya; Tokuyasu, Miki; Himeno, Taichi [Department of Molecular Biology, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan); Watanabe, Kazuhito [Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa 920-1181 (Japan); Omiecinski, Curtis J. [Center for Molecular Toxicology and Carcinogenesis, 101 Life Sciences Building, Pennsylvania State University, University Park, PA 16802 (United States); Aramaki, Hironori [Department of Molecular Biology, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan); Drug Innovation Research Center, Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511 (Japan)

2014-12-04

We recently reported that Δ{sup 9}-tetrahydrocannabinol (Δ{sup 9}-THC), a major cannabinoid component in Cannabis Sativa (marijuana), significantly stimulated the expression of fatty acid 2-hydroxylase (FA2H) in human breast cancer MDA-MB-231 cells. Peroxisome proliferator-activated receptor α (PPARα) was previously implicated in this induction. However, the mechanisms mediating this induction have not been elucidated in detail. We performed a DNA microarray analysis of Δ{sup 9}-THC-treated samples and showed the selective up-regulation of the PPARα isoform coupled with the induction of FA2H over the other isoforms (β and γ). Δ{sup 9}-THC itself had no binding/activation potential to/on PPARα, and palmitic acid (PA), a PPARα ligand, exhibited no stimulatory effects on FA2H in MDA-MB-231 cells; thus, we hypothesized that the levels of PPARα induced were involved in the Δ{sup 9}-THC-mediated increase in FA2H. In support of this hypothesis, we herein demonstrated that; (i) Δ{sup 9}-THC activated the basal transcriptional activity of PPARα in a concentration-dependent manner, (ii) the concomitant up-regulation of PPARα/FA2H was caused by Δ{sup 9}-THC, (iii) PA could activate PPARα after the PPARα expression plasmid was introduced, and (iv) the Δ{sup 9}-THC-induced up-regulation of FA2H was further stimulated by the co-treatment with L-663,536 (a known PPARα inducer). Taken together, these results support the concept that the induced levels of PPARα may be involved in the Δ{sup 9}-THC up-regulation of FA2H in MDA-MB-231 cells.

8C.02

DEFF Research Database (Denmark)

Jensen, B L; Frederiksen-Moller, B; Jorgensen, J S

2015-01-01

OBJECTIVE: The serine protease prostasin (PRSS8, CAP1) and its activator matriptase and inhibitor nexin-1 are necessary for normal placental development in mice. Prostasin is regulated by aldosterone in the kidney and may activate the epithelial sodium channel (ENaC). Preeclampsia is characterized...... by disturbed placentation, suppression of aldosterone and avid renal sodium retention with hypertension. It was hypothesized that preeclampsia is associated with low prostasin expression in placenta and spillover of prostasin into urine across the defect glomeular barrier. DESIGN AND METHOD: The hypothesis...... or placental weight. In summary, preeclampsia is associated with increased urine but not plasma or tissue prostasin CONCLUSIONS: : It is concluded that placental and plasma prostasin level is not controlled by aldosterone during term pregnancy. In contrast, prostasin is aberrantly filtered and may contribute...

Structural and electrochemical properties of La{sub 0.8}Sr{sub 0.2}Ga{sub 1-x}Fe{sub x}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Mori, Kazuhiro [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)], E-mail: kmori@rri.kyoto-u.ac.jp; Onodera, Yohei [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Kiyanagi, Ryoji; Richardson, James W. [Intense Pulsed Neutron Source Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Itoh, Keiji; Sugiyama, Masaaki [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Kamiyama, Takashi [Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Fukunaga, Toshiharu [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

2009-02-21

Mixed ionic-electronic conductor of Fe doped lanthanum gallate, La{sub 0.8}Sr{sub 0.2}Ga{sub 1-x}Fe{sub x}O{sub 3}, has been studied by the dc four-probe method and the neutron powder diffraction. In the electrical conductivity measurement at RT, insulator-metal transition-like phenomenon was observed at around x{approx}0.35; this suggests an existence of the percolation limit for the electronic conductivity. Simultaneously, a bond length between O atoms, l{sub O-O}, in a MO{sub 6} octahedron (M=Ga{sub 1-x}Fe{sub x}) drastically expands over x{approx}0.4, according to the result of crystal structure refinement based on the hexagonal phase. Such a drastic expansion in the l{sub O-O} would induce the decrease in the oxygen ionic conductivity.

Thermally-induced electronic relaxation in structurally-modified Cu0.1Ni0.8Co0.2Mn1.9O4 spinel ceramics

International Nuclear Information System (INIS)

Shpotyuk, O.; Balitska, V.; Brunner, M.; Hadzaman, I.; Klym, H.

2015-01-01

Thermally-induced electronic relaxation in structurally-modified Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 spinel ceramics is shown to be adequately described by stretched exponential function on time. This kinetics is defined by microsctructure perfectness of the relaxing media, showing obvious onset to stretched exponential behaviour with non-exponentionality index attaining close to 0.43 values for high-monolith ceramics and smaller ones in fine-grained ceramics. Percolation threshold in relaxation-degradation kinetics is detected for ceramics with 10% of NiO extractions, showing the smallest but most prolonged single-path degradation effect. This finding is treated in terms of Phillips’ axiomatic diffusion-to-trap model, where only one of two relaxation channels (caused by operative short-range forces) occurs to be effective, while additional non-operative channels contribute to electronic relaxation in fine-grained ceramics

Clock generation and distribution for the 130-nm Itanium$^{R}$ 2 processor with 6-MB on-die L3 cache

CERN Document Server

Tam, S; Limaye, R D

2004-01-01

The clock generation and distribution system for the 130-nm Itanium 2 processor operates at 1.5 GHz with a skew of 24 ps. The Itanium 2 processor features 6 MB of on-die L3 cache and has a die size of 374 mm/sup 2/. Fuse-based clock de-skew enables post-silicon clock optimization to gain higher frequency. This paper describes the clock generation, global clock distribution, local clocking, and the clock skew optimization feature.

A robust NiO-Sm0.2Ce0.8O1.9 anode for direct-methane solid oxide fuel cell

KAUST Repository

Tian, Dong

2015-07-02

In order to directly use methane without a reforming process, NiO-Sm0.2Ce0.8O1.9 (NiO-SDC) nanocomposite anode are successfully synthesized via a one-pot, surfactant-assisted co-assembly approach for direct-methane solid oxide fuel cells. Both NiO with cubic phase and SDC with fluorite phase are obtained at 550 °C. Both NiO nanoparticles and SDC nanoparticles are highly monodispersed in size with nearly spherical shapes. Based on the as-synthesized NiO-SDC, two kinds of single cells with different micro/macro-porous structure are successfully fabricated. As a result, the cell performance was improved by 40%-45% with the new double-pore NiO-SDC anode relative to the cell performance with the conventional NiO-SDC anode due to a wider triple-phase-boundary (TPB) area. In addition, no significant degradation of the cell performance was observed after 60 hours, which means an increasing of long term stability. Therefore, the as-synthesized NiO-SDC nanocomposite is a promising anode for direct-methane solid oxide fuel cells.

Heavy reflector experiments in the IPEN/MB-01 reactor

International Nuclear Information System (INIS)

Santos, Adimir dos; Silva, Graciete Simoes de Andrade e; Mura, Luis Felipe; Fuga, Rinaldo; Jerez, Rogerio; Mendonca, Arlindo Gilson

2012-01-01

Full text: The heavy reflector experiments performed in the IPEN/MB-01 research reactor facility comprise a set of critical configurations employing the standard 28x26-fuel-rod configuration. The heavy reflector either Stainless Steel, Carbon Steel or Nickel plates was placed at one of the faces of the IPEN/MB-01 reactor. Criticality is achieved by inserting the control banks BC1 and BC2 to the critical position. 32 plates around 0.3 mm thick were used in the experiment. The chosen distance between last fuel rod row and the first laminate for both type of laminates was 5.5 mm. Considering initially the SS case, the experimental data reveal that the reactivity decreases up to the sixth plate and after that it increases, becomes nearly zero (which was equivalent to initial zero excess reactivity with zero plates) for the 21 plates case and reaches a value of 154.91 pcm when the whole set of 32 plates are inserted in the reflector. This is a very striking result because it demonstrates that when all 32 plates are inserted in the reflector there is a net gain of reactivity. The reactivity behavior demonstrates all the physics events already mentioned in this work. When the number of plates are small (around 6), the neutron absorption in the plates is more important than the neutron reflection and the reactivity decreases. This condition holds up to a point where the neutron reflection becomes more important than the neutron absorption in the plates and the reactivity increases. The experimental data for the Carbon Steel and Nickel case shows the main features of the SS case, but for the Carbon Steel case the reactivity gain is small, thus demonstrating that Carbon Steel or essentially iron has not the reflector capability as the SS laminates do. The measured data of Nickel plates show a higher reactivity gain, thus demonstrating that Nickel is a good reflector. The theoretical analysis employing MCNP5 and ENDF/B-VII.0 show that the SS calculated results are in a good

16 CFR Figure 8 to Part 1633 - Jig for Setting Mattresses and Foundation Sides in Same Plane

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2010-01-01

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Enhanced electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode at high cutoff voltage by modifying electrode/electrolyte interface with lithium metasilicate

International Nuclear Information System (INIS)

Fu, Jiale; Mu, Daobin; Wu, Borong; Bi, Jiaying; Liu, Xiaojiang; Peng, Yiyuan; Li, Yiqing; Wu, Feng

2017-01-01

Highlights: •The electrochemical properties of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode are investigated at high voltage of 4.6 V. •The Li 2 SiO 3 suppresses the decomposition of LiPF 6 and carbonate solvents. •Li 2 SiO 3 helpfully retards the transition metal dissolution by consuming HF. •The enhanced electrochemical properties of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode mixed with Li 2 SiO 3 . -- Abstract: Developing high-voltage Li ion batteries (LIBs) is an important trend to meet the requirement of high energy density battery. However, high voltage will cause a series of problems harming the cycle performance of LIBs at the same time. This work is to investigate the effect of inorganic substance Li 2 SiO 3 on the electrochemical performance of LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathode at high cutoff voltage of 4.6 V. XRD result shows that the structure of NCM622 cathode material is not affected by mixing Li 2 SiO 3 . However, XPS and EIS tests indicate that Li 2 SiO 3 has an evident influence on suppressing the decomposition of LiPF 6 and carbonate solvents at high voltage, reducing interfacial solid film impedance and modifying electrode/electrolyte interface. In addition, Li 2 SiO 3 retards the transition metal dissolution by consuming HF. Therefore, it enhances the electrochemical properties of the NCM622 cathode significantly. The highest discharge capacity increases to 191.7 mA h g -1 by mixing Li 2 SiO 3 , compared with the value of 180 mA h g -1 in the case of NCM622 cathode. The NCM622 electrode mixed with Li 2 SiO 3 also exhibits a better capacity retention of 73.4% after 200 cycles and a high rate capability at 20C with the value of 89 mA h g -1 , in contrast with 62.2% and 31 mA h g -1 attained in the NCM622 cathode.

EFFECT OF RHODIUM INFILTRATION ON THE MICROSTRUCTURE AND PERFORMANCE OF Ni/Ce0.8Gd0.2O2-δ CERMET ANODE FOR LOW TEMPERATURE SOLID OXIDE FUEL CELL

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F. Torknik

2016-03-01

Full Text Available In order to further enhance the Ni/Ce 0.8Gd0.2O2-δ (Ni/GDC20 cermet anodic performance for low temperature solid oxide fuel cell (LT-SOFC, a study was conducted on the nanostructuring of NiO/GDC composite by only once wet-infiltration of rhodium chloride precursor. By using electrochemical impedance spectroscopy (EIS analysis, the effect of only one drop of Rh-infiltrating solution on the anodic polarization resistance was examined using symmetric Ni–GDC20|GDC20|Pt electrolyte-supported cell at 400-600 °C. Nanostructural evolution before and after H 2 reduction at 600 °C and also after anodic performance test was investigated by atomic force microscopy (AFM, field emission scanning electron microscopy (FE-SEM, and transmission electron microscopy (TEM techniques in comparison to the anode itself. Despite the fine distribution of Rh-infiltrated nanoparticles having average particle size of 11.7 nm, the results showed ineffectiveness and inability of the Rh nanoparticles to succeed in decreasing of anodic polarization resistance for H 2 oxidation reaction in LT-SOFC.

Enhancement-mode two-channel triple quantum dot from an undoped Si/Si0.8Ge0.2 quantum well hetero-structure.

Energy Technology Data Exchange (ETDEWEB)

Studenikin, S. A.; Gaudreau, L.; Kataoka, K.; Austing, D. G.; Lu, Tzu-Ming; Luhman, Dwight; Bethke, Donald Thomas; Wanke, Michael; Lilly, Michael; Carroll, Malcolm S.; Sachrajda, A. S.

2017-12-01

We demonstrate coupled triple dot operation and charge sensing capability for the recently introduced quantum dot technology employing undoped Si/Si_0.8Ge_0.2 hetero-structures which also incorporate a single metal-gate layer to simplify fabrication [T. M. Lu et al., Appl. Phys. Lett. 109, 093102 (2016)]. Si/SiGe hetero-structures with a Ge concentration of 20% rather than the more usual 30% typically encountered offer higher electron mobility. The devices consist of two in-plane parallel electron channels that host a double dot in one channel and a single dot in the other channel. In a device where the channels are sufficiently close a triple dot in a triangular configuration is induced leading to regions in the charge stability diagram where three addition lines of different slope approach each other and anti-cross. In a device where the channels are further apart the single dot charge-senses the double dot with relative change of ~2% in the sensor current. We also highlight temporal drifting and metastability of the Coulomb oscillations. These effects are induced if the temperature environment of the device is not kept constant and arise from non-equilibrium charge redistribution and subsequent slow recovery.

Pseudorapidity distributions of charged hadrons in proton-lead collisions at √{s_{NN}}=5.02 and 8.16 TeV

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