Annealing effect on thermal conductivity and microhardness of carbon nanotube containing Se80Te16Cu4 glassy composites

NASA Astrophysics Data System (ADS)

Upadhyay, A. N.; Tiwari, R. S.; Singh, Kedar

2018-02-01

This study deals with the effect of thermal annealing on structural/microstructural, thermal and mechanical behavior of pristine Se80Te16Cu4 and carbon nanotubes (CNTs) containing Se80Te16Cu4 glassy composites. Pristine Se80Te16Cu4, 3 and 5 wt%CNTs-Se80Te16Cu4 glassy composites are annealed in the vicinity of glass transition temperature to onset crystallization temperature (340-380 K). X-ray diffraction (XRD) pattern revealed formation of polycrystalline phases of hexagonal CuSe and trigonal selenium. The indexed d-values in XRD patterns are in well conformity with the d-values obtained after the indexing of the ring pattern of selected area electron diffraction pattern of TEM images. The SEM investigation exhibited that the grain size of the CNTs containing Se80Te16Cu4 glassy composites increased with increasing annealing temperature and decreased at further higher annealing temperature. Thermal conductivity, microhardness exhibited a substantial increase with increasing annealing temperature of 340-360 K and slightly decreases for 380 K. The variation of thermal conductivity and microhardness can be explained by cross-linking formation and voids reduction.

(Cu 0.5Tl 0.5)Ba 2Ca n-1 Cu n- yGe yO 2 n+4- δ ( n = 3, 4 and y = 0.5, 0.75, 1.0); superconductors with GeO 2 planes

NASA Astrophysics Data System (ADS)

Khan, Nawazish A.; Irfan, M.

2008-12-01

We have successfully synthesized germanium doped (Cu 0.5Tl 0.5)Ba 2Ca n-1 Cu n- yGe yO 2 n+4- δ ( n = 3, 4 and y = 0, 0.5, 0.75, 1.0) superconductors and investigated the effect of Ge doping on the superconducting properties of these compounds. The solubility of Ge till y = 1 in the CuO 2 planes of (Cu 0.5Tl 0.5)Ba 2Ca 2Cu 3- yGe yO 10- δ, have been found to give superconductivity above 77 K. To our surprise an enhanced superconductivity is observed with the doping of semiconductor germanium in some samples. The enhanced superconductivity associated with mixed CuO 2/GeO 2 planes can be extremely useful for the understanding of mechanism of superconductivity; since we very well know the properties of germanium based semiconductors.

Improving properties of Mg with Al–Cu additions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashad, Muhammad, E-mail: rashadphy87@gmail.com; National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044; Pan, Fusheng, E-mail: fspan@cqu.edu.cn

The present work reports improvement in tensile properties of the Mg matrix reinforced with micron-sized copper–aluminum particulate hybrids. The Al–Cu particulate hybrids were incorporated into the Mg matrix through powder metallurgy method. The synthesized alloys exhibited homogeneously dispersed Mg{sub 2}Cu particles in the matrix, therefore leading to a 110% increase in yield strength (221 MPa) and a 72% enhancement in ultimate tensile strength (284 MPa) by addition of 1.0 wt.%Al–0.6 wt.%Cu particle hybrids. Optical microscopy, scanning election microscopy, transmission electron microscopy and X-ray diffraction were used to investigate the microstructure and intermetallic phases of the synthesized alloys. - Highlights: •more » Mg matrix is reinforced with Al–Cu particulate hybrids. • Powder metallurgic method is used to fabricate the alloys. • Tensile strength and ductility were increased simultaneously.« less

EPR and ESE of CuS4 complex in Cu(dmit)2: g-Factor and hyperfine splitting correlation in tetrahedral Cu-sulfur complexes

NASA Astrophysics Data System (ADS)

Hoffmann, Stanisław K.; Goslar, Janina; Lijewski, Stefan; Zalewska, Alina

2013-11-01

Pseudotetrahedral CuS4 complexes of Cu(dmit)2 compound in DMF solution were studied by EPR, UV-Vis and electron spin echo methods. After rapid freezing at 77 K a good glassy state is formed and the CuS4 complex has a D2d symmetry of a compressed tetrahedron with xy ground state and spin-Hamiltonian parameters g|| = 2.089, g⊥ = 2.026, A|| = 146 × 10-4 cm-1 and A⊥ = 30 × 10-4 cm-1. The complex is not deformed in the glassy state and is very rigid as indicated by the echo detected spectrum and by electron spin relaxation which is governed by reorientations of methyl groups of surrounding DMF molecules as shown by electron spin echo envelope modulation (ESEEM) spectrum. The g|| and A|| of Cu(dmit)2 and other CuS4 complexes collected in Peisach-Blumberg correlation diagram were analyzed using extended Molecular Orbital theory. We explain why the correlation line for copper-sulfur complexes has larger slope compared to the CuO4 and CuN4 tetrahedra. Along the correlation line the delocalization of unpaired electron density onto ligand is constant and varies from β = 0.78-0.83 for g|| in the range 2.06-2.10 of correlation diagram. The slope of the line is determined by the product of MO-coefficients αc1, where α is a parameter characterizing delocalization of unpaired electron in x2-y2 and c1 < 1 is a mixing parameter decreasing when 4p contribution grows. We found, unexpectedly, that αc1≈0.7 for all CuS4 complexes suggesting a correlation between degree of tetrahedral deformation and MO-parameters. MO-coefficients for Cu(dmit)2 are α = 0.753, β = 0.752 and c1 = 0.930 confirming a strong delocalization of unpaired electron in xy and x2-y2 orbitals.

The effect of Mg-doping and Cu nonstoichiometry on the photoelectrochemical response of CuFeO 2

DOE PAGES

Wuttig, Anna; Krizan, Jason W.; Gu, Jing; ...

2016-11-14

Here, we report the tuning of CuFeO 2 photoelectrodes by Mg doping and Cu deficiency to demonstrate the effects of carrier concentration on the photoresponse. Carrier type and concentration were quantitatively assessed using the Hall effect on pure, Mg-incorporated, and Cu-deficient pellets (CuFe 1–xMg xO 2 and Cu 1–yFeO 2, x = 0, 0.0005, 0.005, 0.02, and y = 0.005, 0.02) over the range of thermodynamic stability achievable using solid-state synthesis. The same samples were used in a photoelectrochemical cell to measure their photoresponse. We find that the material with the lowest p-type carrier concentration and the highest carrier mobilitymore » shows the largest photoresponse. Furthermore, we show that increasing the p-type carrier concentration and thus the conductivity to high levels is limited by the delafossite defect chemistry, which changes the majority carrier type from p-type to n-type near the Mg solubility limit (x = 0.05) and at high Cu defect concentrations.« less

Electrical resistivity in Zr48Nb8Cu12Fe8Be24 glassy and crystallized alloys

NASA Astrophysics Data System (ADS)

Bai, H. Y.; Tong, C. Z.; Zheng, P.

2004-02-01

The electrical resistivity of Zr48Nb8Cu12Fe8Be24 bulk metallic glassy and crystallized alloys in the temperature range of 4.2-293 K is investigated. It is found that the resistivity in glassy and crystallized states shows opposite temperature coefficients. For the metallic glass, the resistivity shows a negative logarithmic dependence at temperatures below 16 K, whereas it has more normal behavior for the crystallized alloy. At higher temperatures, the resistivity in both glassy and crystallized alloys shows dependence upon both T and T2, but the signs of the T and T2 terms are opposite. The results are interpreted in terms of scattering from two-level tunneling states in glasses and the generalized Ziman diffraction model.

Investigation of Pd-Modified Ag-CuO Air Braze Filler Metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darsell, Jens T.; Hardy, John S.; Kim, Jin Yong

2006-01-10

Palladium was added as a ternary component to a series of silver - copper oxide alloys in an effort to increase the use temperature of these materials for potential ceramic air brazing applications. Large portions of the silver component of the Ag-CuO system were substituted by palladium forming the following alloys: (100-y)[(100-z)Pd - (z)Ag] - (y)CuOx where y = 0 - 34 mol% CuOx, z = 50 - 100 mol% silver, and x = 0, 0.5, and 1, denoting copper metal, Cu2O, or CuO. From differential scanning calorimetry, it was determined that the addition of palladium causes an increase inmore » the solidus and liquidus temperatures of the resulting Pd-Ag-CuO brazes. In general, the liquidus was found to increase by approximately 220°C for the (100-y)(25Pd - 75Ag) - (z)CuOx filler metal compositions relative to comparable Ag-CuOx alloys. Likewise, the solidus was found to increase for these alloys, respectively by 185°C and 60°C, respectively for CuOx contents of y = 0 - 1mol% and 4 - 10 mol%. For the (100-y)(50Pd - 50Ag) - (y)CuOx alloys, the solidus increased between 280 - 390°C over a copper oxide compositional range of x = 0 to 8 mol%. It was determined from sessile drop experiments that palladium causes an increase in the wetting angle for all of the samples tested. Alloy compositions of (100-y)(25Pd - 75Ag) - (y)CuOx displayed increased wetting angles of 5-20° relative to comparable binary compositions. (100-y)(50Pd - 50Ag) - (y)CuOx alloys exhibited an increase in contact angle of 10-60° and compositions containing less than 10 mol% CuOx were not able to wet the substrate. Scanning electron microscopy indicates that the microstructure of the braze consists of Ag-Pd solid solution with CuOx precipitates. In general, a reaction layer consisting of CuAlO2 forms adjacent to the alumina substrate. However, the formation of this layer is apparently hindered by the addition of large amounts of palladium, causing poor wetting behavior, as denoted by substantial porosity

CHARACTERISTICS OF THERMOLUMINESCENCE LiF:Mg,Cu,Ag NANOPHOSPHOR.

PubMed

Yahyaabadi, A; Torkzadeh, F; Rezaei-Ochbelagh, D

2018-04-23

A nanophosphor of LiF:Mg,Cu,Ag was prepared by planetary ball milling for the first time in the laboratory. The size and shape of the nanophosphor were confirmed by XRD and SEM, which showed that it was cubic in shape and ~53 nm in size. The thermoluminescence (TL) characteristics of this nanophosphor were then investigated. It was found that the optimum annealing condition was 250°C for 10 min. The TL sensitivity of the prepared nanopowder was less than that of its micropowder counterpart and the TL glow curve structure exhibited several peaks. The LiF:Mg,Cu,Ag nanophosphor exhibited a linear response over a range of doses from 1 Gy to ~10 kGy. From this study, it appears that LiF:Mg,Cu,Ag nanophosphor is a good candidate for dosimetry because of its linearity over a range of doses, low tendency to fade, good repeatability and simple glow curve structure.

Electronic structure of Pr{sub 1{minus}x}Y{sub x}Ba{sub 2}Cu{sub 3}O{sub y} (x=0, 0.5, and 1.0)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kakinuma, K.; Fueki, K.

1997-08-01

In order to elucidate the reason why PrBa{sub 2}Cu{sub 3}O{sub y}is not a superconductor, we examined the Pr valence and measured the oxygen nonstoichiometry and the conductivity at temperatures up to 1200 K for three kinds of oxides, PrBa{sub 2}Cu{sub 3}O{sub y}, (Pr{sub 0.5}Y{sub 0.5})Ba{sub 2}Cu{sub 3}O{sub y}, and YBa{sub 2}Cu{sub 3}O{sub y}. The valence of Pr was found to be +3. Any difference was not found in oxygen nonstoichiometry and conductivity among three kinds of oxides. We analyzed the data of oxygen nonstoichiometry on the basis of defect thermodynamics and calculated the numbers of Cu{sup +}, Cu{sup 2+}, andmore » Cu{sup 3+} ions in the unit cell as a function of y. The number of Cu{sup 3+} ions (the amount of holes) was found to be proportional to ({Delta}y){sup 1.6}({Delta}y=y{minus}6.0), whereas the conductivity was found to be proportional to ({Delta}y){sup 3.2} in these oxides. We interpreted the remarkable increase of {sigma} with {Delta}y as an evidence of the increase of both mobility and hole concentration with {Delta}y. At high temperatures, we detected the conductivity minimum {sigma}{sub min} which was found in the log{sub 10}{sigma}{minus}log{sub 10}P{sub O{sub 2}} plot at constant temperatures. From the slope of the Arrhenius plot for {sigma}{sub min}, the band gap was determined to be 1.21, 1.32, and 1.37 eV for PrBa{sub 2}Cu{sub 3}O{sub y}, (Pr{sub 0.5}Y{sub 0.5})Ba{sub 2}Cu{sub 3}O{sub y} and YBa{sub 2}Cu{sub 3}O{sub y}, respectively. We determined the conductivity of the same oxygen content as a function of temperature from 4.2 to 1200 K. The energy gap {Delta}E between the acceptor level and the top of the valence band was calculated from the slope of the Arrhenius plot for conductivity. {Delta}E for superconducting YBa{sub 2}Cu{sub 3}O{sub y} and (Pr{sub 0.5}Y{sub 0.5})Ba{sub 2}Cu{sub 3}O{sub y} were zero at 300 K but that for nonsuperconducting PrBa{sub 2}Cu{sub 3}O{sub y} was 20 meV at 100 K even for y=6.93. (Abstract

Hydriding and dehydriding rates of Mg, Mg-10TaF5, and Mg-10NbF5 prepared via reactive mechanical grinding

NASA Astrophysics Data System (ADS)

Song, Myoung Youp; Kwak, Young Jun; Lee, Seong Ho; Park, Hye Ryoung

2015-01-01

In this work, TaF5 and NbF5 were chosen as additives to enhance the hydriding and dehydriding rates of Mg. Mg, Mg-10TaF5, and Mg-10NbF5 samples were prepared by reactive mechanical grinding. The hydriding and dehydriding properties of the samples were then examined. Mg-10TaF5 had the largest amount of hydrogen absorbed for 30 min and the highest initial dehydriding rate after incubation period, followed in order by Mg-10NbF5, and Mg. At 593 K under 12 bar H2 at the first cycle, Mg-10TaF5 absorbed 3.63 wt% H for 5 min and 4.53 wt% H for 30 min. At 593 K under 1.0 bar H2 at the first cycle, Mg-10TaF5 desorbed 0 wt% H for 2.5 min, 0.59 wt% H for 5 min, 3.42 wt% H for 30 min, and 4.24 wt% H for 60 min. The reactive mechanical grinding of Mg with TaF5 or NbF5 is believed to have facilitated the nucleation and to have decreased the diffusion distances of hydrogen atoms. These two effects are believed to have increased the hydriding and dehydriding rates of Mg. The MgF2 and Ta2H formed in Mg-10TaF5, and the MgF2, NbH2, and NbF3 formed in Mg-10NbF5 are considered to have enhanced both of these effects.

Study on glass-forming ability and hydrogen storage properties of amorphous Mg{sub 60}Ni{sub 30}La{sub 10−x}Co{sub x} (x = 0, 4) alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lv, Peng; Wang, Zhong-min, E-mail: zmwang@guet.edu.cn; Zhang, Huai-gang

2013-12-15

Mg{sub 60}Ni{sub 30}La{sub 10−x}Co{sub x} (x = 0, 4) amorphous alloys were prepared by rapid solidification, using a melt-spinning technique. X-ray diffraction and differential scanning calorimetry analysis were employed to measure their microstructure, thermal stability and glass-forming ability, and hydrogen storage properties were studied by means of PCTPro2000. Based on differential scanning calorimetry results, their glass-forming ability and thermal stability were investigated by Kissinger method, Lasocka curves and atomic cluster model, respectively. The results indicate that glass-forming ability, thermal properties and hydrogen storage properties in the Mg-rich corner of Mg–Ni–La–Co system alloys were enhanced by Co substitution for La. Itmore » can be found that the smaller activation energy (ΔΕ) and frequency factor (υ{sub 0}), the bigger value of B (glass transition point in Lasocka curves), and higher glass-forming ability of Mg–Ni–La–Co alloys would be followed. In addition, atomic structure parameter (λ), deduced from atomic cluster model is valuable in the design of Mg–Ni–La–Co system alloys with good glass-forming ability. With an increase of Co content from 0 to 4, the hydrogen desorption capacity within 4000 s rises from 2.25 to 2.85 wt.% at 573 K. - Highlights: • Amorphous Mg{sub 60}Ni{sub 30}La{sub 10−x}Co{sub x} (x = 0 and 4) alloys were produced by melt spinning. • The GFA and hydrogen storage properties were enhanced by Co substitution for La. • With an increase of Co content, the hydrogen desorption capacity rises at 573 K.« less

Physical properties of single crystalline R Mg 2 Cu 9 ( R = Y , Ce - Nd , Gd - Dy , Yb ) and the search for in-plane magnetic anisotropy in hexagonal systems

DOE PAGES

Kong, Tai; Meier, William R.; Lin, Qisheng; ...

2016-10-24

Single crystals of RMg 2Cu 9 (R=Y, Ce-Nd, Gd-Dy, Yb) were grown using a high-temperature solution growth technique and were characterized by measurements of room-temperature x-ray diffraction, temperature-dependent specific heat, and temperature- and field-dependent resistivity and anisotropic magnetization. YMg 2Cu 9 is a non-local-moment-bearing metal with an electronic specific heat coefficient, γ ~ 15 mJ/mol K 2. Yb is divalent and basically non-moment-bearing in YbMg2Cu9. Ce is trivalent in CeMg 2Cu 9 with two magnetic transitions being observed at 2.1 K and 1.5 K. PrMg 2Cu 9 does not exhibit any magnetic phase transition down to 0.5 K. The othermore » members being studied ( R = Nd, Gd-Dy) all exhibit antiferromagnetic transitions at low temperatures ranging from 3.2 K for NdMg 2Cu 9 to 11.9 K for TbMg 2Cu 9. Whereas GdMg 2Cu 9 is isotropic in its paramagnetic state due to zero angular momentum ( L = 0), all the other local-moment-bearing members manifest an anisotropic, planar magnetization in their paramagnetic states. To further study this planar anisotropy, detailed angular-dependent magnetization was carried out on magnetically diluted (Y 0.99Tb 0.01)Mg 2Cu 9 and (Y 0.99Dy 0.01)Mg 2Cu 9. Despite the strong, planar magnetization anisotropy, the in-plane magnetic anisotropy is weak and field-dependent. Finally, a set of crystal electric field parameters are proposed to explain the observed magnetic anisotropy.« less

Physical properties of single crystalline R Mg 2 Cu 9 ( R = Y , Ce - Nd , Gd - Dy , Yb ) and the search for in-plane magnetic anisotropy in hexagonal systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kong, Tai; Meier, William R.; Lin, Qisheng

Single crystals of RMg 2Cu 9 (R=Y, Ce-Nd, Gd-Dy, Yb) were grown using a high-temperature solution growth technique and were characterized by measurements of room-temperature x-ray diffraction, temperature-dependent specific heat, and temperature- and field-dependent resistivity and anisotropic magnetization. YMg 2Cu 9 is a non-local-moment-bearing metal with an electronic specific heat coefficient, γ ~ 15 mJ/mol K 2. Yb is divalent and basically non-moment-bearing in YbMg2Cu9. Ce is trivalent in CeMg 2Cu 9 with two magnetic transitions being observed at 2.1 K and 1.5 K. PrMg 2Cu 9 does not exhibit any magnetic phase transition down to 0.5 K. The othermore » members being studied ( R = Nd, Gd-Dy) all exhibit antiferromagnetic transitions at low temperatures ranging from 3.2 K for NdMg 2Cu 9 to 11.9 K for TbMg 2Cu 9. Whereas GdMg 2Cu 9 is isotropic in its paramagnetic state due to zero angular momentum ( L = 0), all the other local-moment-bearing members manifest an anisotropic, planar magnetization in their paramagnetic states. To further study this planar anisotropy, detailed angular-dependent magnetization was carried out on magnetically diluted (Y 0.99Tb 0.01)Mg 2Cu 9 and (Y 0.99Dy 0.01)Mg 2Cu 9. Despite the strong, planar magnetization anisotropy, the in-plane magnetic anisotropy is weak and field-dependent. Finally, a set of crystal electric field parameters are proposed to explain the observed magnetic anisotropy.« less

La 139 and Cu 63 NMR investigation of charge order in La 2 CuO 4 + y ( T c = 42 K)

DOE PAGES

Imai, T.; Lee, Y. S.

2018-03-14

Here, we report 139La and 63Cu NMR investigation of the successive charge order, spin order, and superconducting transitions in superoxygenated La 2CuO 4+y single crystal with stage-4 excess oxygen order at T stage≃290 K. We show that the stage-4 order induces tilting of CuO 6 octahedra below T stage, which in turn causes 139La NMR line broadening. The structural distortion continues to develop far below Tstage, and completes at T charge≃60 K, where charge order sets in. This sequence is reminiscent of the the charge-order transition in Nd codoped La 1.88Sr 0.12CuO 4 that sets in once the low-temperature tetragonalmore » phase is established. We also show that the paramagnetic 63Cu NMR signals are progressively wiped out below T charge due to enhanced low-frequency spin fluctuations in charge-ordered domains, but the residual 63Cu NMR signals continue to exhibit the characteristics expected for optimally doped superconducting CuO 2 planes. This indicates that charge order in La 2CuO 4+y does not take place uniformly in space. In addition, unlike the typical second-order magnetic phase transitions, low-frequency Cu spin fluctuations as probed by 139La nuclear spin-lattice relaxation rate do not exhibit critical divergence at T spin(≃T c) =42 K. These findings, including the spatially inhomogeneous nature of the charge-ordered state, are qualitatively similar to the case of La 1.885Sr 0.115CuO 4, but both charge and spin order take place more sharply in the present case.« less

La 139 and Cu 63 NMR investigation of charge order in La 2 CuO 4 + y ( T c = 42 K)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imai, T.; Lee, Y. S.

Here, we report 139La and 63Cu NMR investigation of the successive charge order, spin order, and superconducting transitions in superoxygenated La 2CuO 4+y single crystal with stage-4 excess oxygen order at T stage≃290 K. We show that the stage-4 order induces tilting of CuO 6 octahedra below T stage, which in turn causes 139La NMR line broadening. The structural distortion continues to develop far below Tstage, and completes at T charge≃60 K, where charge order sets in. This sequence is reminiscent of the the charge-order transition in Nd codoped La 1.88Sr 0.12CuO 4 that sets in once the low-temperature tetragonalmore » phase is established. We also show that the paramagnetic 63Cu NMR signals are progressively wiped out below T charge due to enhanced low-frequency spin fluctuations in charge-ordered domains, but the residual 63Cu NMR signals continue to exhibit the characteristics expected for optimally doped superconducting CuO 2 planes. This indicates that charge order in La 2CuO 4+y does not take place uniformly in space. In addition, unlike the typical second-order magnetic phase transitions, low-frequency Cu spin fluctuations as probed by 139La nuclear spin-lattice relaxation rate do not exhibit critical divergence at T spin(≃T c) =42 K. These findings, including the spatially inhomogeneous nature of the charge-ordered state, are qualitatively similar to the case of La 1.885Sr 0.115CuO 4, but both charge and spin order take place more sharply in the present case.« less

Nanocrystallization of Zr-Cu-Ni-Al-Au glassy alloys during severe plastic deformation

NASA Astrophysics Data System (ADS)

Yamada, Masahiro; Kamisato, Ryo; Yamasaki, Tohru; Adachi, Hiroki; Tsuchiya, Koichi; Yokoyama, Yoshihiko

2014-08-01

A study has been carried out into the formation of nanocrystalline grains during high-pressure torsion (HPT) deformation of Zr65Cu17Ni5Al10Au3 bulk alloys prepared using tilt casting. As a preliminary to this, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses were carried out on as-cast Zr65+xCu17-xNi5Al10Au3 (x=0~5 at.%) and Zr65Cu20Ni5Al10Au3 alloys, in order to determine the effect on the microstructure of the excess Zr content x and the presence of Au. From the XRD patterns, it was determined that all of the alloys had a metallic glassy nature. For Zr65Cu17Ni5Al10Au3, the DSC results indicated the presence of a wide supercooled liquid region between the glass transition temperature (Tg) of 644 K and the crystallization temperature of 763 K, where the stable body-centered tetragonal Zr2Cu phase was formed. In contrast, for the Zr65+xCu17-xNi5Al10Au3 alloys, precipitation of an icosahedral quasicrystalline phase (I-phase) was observed in the supercooled liquid region at about 715 K. HPT deformation of the Zr65Cu17Ni5Al10Au3 alloys was carried out under a high pressure of 5 GPa. Both as-cast specimens and those annealed at Tg-50 K for 90 min were used. Following a single HPT rotation (N=1), transmission electron microscopy identified the presence of face- centered cubic Zr2Ni precipitates in the as-cast alloy, with a size of about 50 nm. For the annealed alloy, a high density of I-phase precipitates with sizes of less than 10 nm was observed following HPT with N=10, indicating that the combination of severe plastic deformation and annealing is effective at producing extremely small grains.

Plasma sprayed coatings for containment of Cu-Mg-Si metallic phase change material

DOE PAGES

Withey, Elizabeth Ann; Kruizenga, Alan Michael; Andraka, Charles E.; ...

2016-01-01

In this study, the performance of Y 2O 3-stabilized ZrO 2 (YSZ), Y 2O 3, and Al 2O 3 plasma sprayed coatings are investigated for their ability to prevent attack of Haynes 230 by a near-eutectic Cu-Mg-Si metallic phase change material (PCM) in a closed environment at 820 °C. Areas where coatings failed were identified with optical and scanning electron microscopy, while chemical interactions were clarified through elemental mapping using electron microprobe analysis. Despite its susceptibility to reduction by Mg, the Al 2O 3 coating performed well while the YSZ and Y 2O 3 coating showed clear areas of attack.more » These results are attributed to the evolution of gaseous Mg at 820 °C leading to the formation of MgO and MgAl 2O 4.« less

Effect of substrate on texture and mechanical properties of Mg-Cu-Zn thin films

NASA Astrophysics Data System (ADS)

Eshaghi, F.; Zolanvari, A.

2018-04-01

In this work, thin films of Mg-Cu-Zn with 60 nm thicknesses have been deposited on the Si(100), Al, stainless steel, and Cu substrates using DC magnetron sputtering. FESEM images displayed uniformity of Mg-Cu-Zn particles on the different substrates. AFM micrograph revealed the roughness of thin film changes due to the different kinds of the substrates. XRD measurements showed the existence of strong Mg (002) reflections and weak Mg (101) peaks. Residual stress and adhesion force have been measured as the mechanical properties of the Mg-Cu-Zn thin films. The residual stresses of thin films which have been investigated by X-ray diffraction method revealed that the thin films sputtered on the Si and Cu substrates endure minimum and maximum stresses, respectively, during the deposition process. However, the force spectroscopy analysis indicated that the films grew on the Si and Cu experienced maximum and minimum adhesion force. The texture analysis has been done using XRD instrument to make pole figures of Mg (002) and Mg (101) reflections. ODFs have been calculated to evaluate the distribution of the orientations within the thin films. It was found that the texture and stress have an inverse relation, while the texture and the adhesion force of the Mg-Cu-Zn thin films have direct relation. A thin film that sustains the lowest residual stresses and highest adhesive force had the strongest {001} basal fiber texture.

The thermoluminescence study of epoxy based LiF:Mg,Cu,P dosimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahangdale, S. R., E-mail: sachin.rahangdale1@gmail.com; Palikundwar, U. A.; Moharil, S. V.

The LiF:Mg,Cu,P phosphor is the most investigated phosphor in radiation dosimetry. Results on thermoluminescence of the epoxy based LiF:Mg,Cu,P dosimeters irradiated with gamma radiations are presented and compared with results of LiF:Mg,Cu,P powder. The glow curve structure of both LiF powder and dosimeter are same and only difference is found in the glow curve peak temperature. The LiF dosimeters were made from the 5012A and 5012B epoxy. The dosimeters had a mass of about 18 mg, 5.0 mm diameter and 0.5 mm thickness. The sensitivity variation of the dosimeters for exposure to {sup 60}Co gamma rays at different angles of incidence of themore » radiation is found to be within 4%. Its minimum detectable dose is about 3020 µGy. The epoxy based dosimeters withstand different environment and it can be used with general TL reader without need of any special design due to its small size and plane surface.« less

Thermal and Compositional Variation of Glassy Metal Structure Factors.

NASA Astrophysics Data System (ADS)

From, Milton

The x-ray total structure factor of the glassy -metal alloys Mg_{70}Zn_ {30}, Ca_{70}Mg_{30 } and Mg_{85.5}Cu _{14.5} has been measured at three temperatures: 9K, 150K, and 300K. The data have a statistical precision of about.8% and an absolute accuracy of roughly 3%. Percus-Yevick hard sphere structure factors may be fitted quite accurately to the data in the region of the first peak. In addition, the variation of the experimental structure factor with composition is found to be consistent with the Percus-Yevick theory. At low k values, Percus -Yevick and other theoretical model structure factors are in poor agreement with the data. Within experimental error, the temperature dependence of the structure factors is in agreement with the Debye plane wave phonon model of atomic vibrations. The measured structure factors are used to calculate the electrical resistivity from the Faber-Ziman equation. In most cases, the calculations yield both the correct magnitude of resistivity and sign of the temperature coefficient of resistivity.

Metallic glassy Zr70Ni20Pd10 powders for improving the hydrogenation/dehydrogenation behavior of MgH2

PubMed Central

El-Eskandarany, M. Sherif

2016-01-01

Because of its low density, storage of hydrogen in the gaseous and liquids states possess technical and economic challenges. One practical solution for utilizing hydrogen in vehicles with proton-exchange fuel cells membranes is storing hydrogen in metal hydrides. Magnesium hydride (MgH2) remains the best hydrogen storage material due to its high hydrogen capacity and low cost of production. Due to its high activation energy and poor hydrogen sorption/desorption kinetics at moderate temperatures, the pure form of MgH2 is usually mechanically treated by high-energy ball mills and catalyzed with different types of catalysts. These steps are necessary for destabilizing MgH2 to enhance its kinetics behaviors. In the present work, we used a small mole fractions (5 wt.%) of metallic glassy of Zr70Ni20Pd10 powders as a new enhancement agent to improve its hydrogenation/dehydrogenation behaviors of MgH2. This short-range ordered material led to lower the decomposition temperature of MgH2 and its activation energy by about 121 °C and 51 kJ/mol, respectively. Complete hydrogenation/dehydrogenation processes were successfully achieved to charge/discharge about 6 wt.%H2 at 100 °C/200 °C within 1.18 min/3.8 min, respectively. In addition, this new nanocomposite system shows high performance of achieving continuous 100 hydrogen charging/discharging cycles without degradation. PMID:27220994

Investigations on structural, vibrational and dielectric properties of nanosized Cu doped Mg-Zn ferrites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Anand; Department of Physics, MEDICAPS Institute of Science and Technology, Pithampur 453331; Rajpoot, Rambabu

2016-05-23

Transition metal Cu{sup 2+} doped Mg-Zn ferrite [Mg{sub 0.5}Zn{sub 0.5-x}Cu{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 0.5)] were prepared by sol gel auto combustion (SGAC) method to probe the structural, vibrational and electrical properties. X-ray diffraction (XRD) pattern reveals a single-phase cubic spinel structure without the presence of any secondary phase corresponding to other structure. The average particle size of the parent Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} is found to be ~29.8 nm and is found to increase with Cu{sup 2+} doping. Progressive reduction in lattice parameter of Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} has been observed due to difference inmore » ionic radii of cations with improved Cu doping. Spinel cubic structure is further confirmed by Raman spectroscopy. Small shift in Raman modes towards higher wave number has been observed in doped Mg-Zn ferrites. The permittivity and dielectric loss decreases at lower doping and increases at higher order doping of Cu{sup 2+}.« less

Apatite layer growth on glassy Zr48Cu36Al8Ag8 sputtered titanium for potential biomedical applications

NASA Astrophysics Data System (ADS)

Thanka Rajan, S.; Karthika, M.; Bendavid, Avi; Subramanian, B.

2016-04-01

The bioactivity of magnetron sputtered thin film metallic glasses (TFMGs) of Zr48Cu36Al8Ag8 (at.%) on titanium substrates was tested for bio implant applications. The structural and elemental compositions of TFMGs were analyzed by XRD, XPS and EDAX. X-ray diffraction analysis displayed a broad hump around the incident angle of 30-50°, suggesting that the coatings possess a glassy structure. An in situ crystal growth of hydroxyapatite was observed by soaking the sputtered specimen in simulated body fluid (SBF). The nucleation and growth of a calcium phosphate (Ca-P) bone-like hydroxyapatite on Zr48Cu36Al8Ag8 (at.%) TFMG from SBF was investigated by using XRD, AFM and SEM. The presence of calcium and phosphorus elements was confirmed by EDAX and XPS. In vitro electrochemical corrosion studies indicated that the Zr-based TFMG coating sustain in the stimulated body-fluid (SBF), exhibiting superior corrosion resistance with a lower corrosion penetration rate and electrochemical stability than the bare crystalline titanium substrate.

Effect of Low Cu Amounts and Pre-Deformation on the Precipitation in Al-Mg-Si Alloys

NASA Astrophysics Data System (ADS)

Saito, Takeshi; Muraishi, Shinji; Marioara, Calin D.; Holmestad, Randi

Transmission electron microscopy (TEM) studies were performed on two Al-Mg-Si alloys with low Cu additions (0.01 and 0.10 wt%) in order to investigate the effect of Cu and 10% pre-deformation on precipitate microstructure and its connection to mechanical properties. After 300 minutes aging at 190°C, fine microstructures associated with high hardness were observed in the alloy with 0.10% Cu. Pre-deformation led to heterogeneous distributions of precipitates along dislocations, causing microstructure coarsening. This effect was less pronounced in the alloy with the higher Cu amount.

Investigations on the local structures of Cu2+ at various BaO concentrations in 59B2O3-10K2O-(30-x)ZnO-xBaO-1CuO glasses

NASA Astrophysics Data System (ADS)

Jin, Jia-Rui; Wu, Shao-Yi; Hong, Jian; Liu, Shi-Nan; Song, Min-Xian; Teng, Bao-Hua; Wu, Ming-He

2017-11-01

The local structures and electron paramagnetic resonance (EPR) parameters for Cu2+ in 59B2O3-10K2O-(30-x)ZnO-xBaO-1CuO (BKZBC) glasses are theoretically investigated with distinct modifier BaO concentrations x (= 0, 6, 12, 18, 24 and 30 mol %). The ? clusters are found to undergo the relative tetragonal elongations of about 13.5 and 5.0% at zero and higher BaO concentrations. The concentration dependences of the measured d-d transition bands, g factors and A// are suitably reproduced from the Fourier type functions or sign functions of the relevant quantities with x by using only six adjustable parameters. The features of the EPR parameters and the local structures of Cu2+ are analysed in a consistent way by considering the differences in the local ligand field strength and electronic cloud admixtures around Cu2+ under addition of Ba2+ with the highest ionicity and polarisability. The present theoretical studies would be helpful to the researches on the structures, optical and EPR properties for the similar potassium barium zinc borate glasses containing copper with variation concentration of modifier BaO.

SPM investigation of local aging effects in glassy polymers

NASA Astrophysics Data System (ADS)

Crider, Philip

2005-03-01

We investigate the cooperative and heterogeneous nature of glassy dynamics by nanometer-scale probing in a glassy polymer, Polyvinyl-Actetate (PVAc), with a Scanning Force Microscope (SFM). Using ultra-high-vacuum (UHV) Scanning Capacitive Force Microscopy techniques, nanometer-scale capacitive responses are probed. Dielectric relaxation near the glass transition is investigated, and scanning capabilities are utilized to analyze spatial response on a nanometer scale. The results of these studies may yield insight into the understanding of temperature-dependent cooperative length scales, local aging properties, and energy landscape properties of evolving dipole clusters on a mesoscopic scale. Results are used to test the validity and relevance of current models of glassy dynamics.

A novel highly selective and sensitive detection of serotonin based on Ag/polypyrrole/Cu2O nanocomposite modified glassy carbon electrode.

PubMed

Selvarajan, S; Suganthi, A; Rajarajan, M

2018-06-01

A silver/polypyrrole/copper oxide (Ag/PPy/Cu 2 O) ternary nanocomposite was prepared by sonochemical and oxidative polymerization simple way, in which Cu 2 O was decorated with Ag nanoparticles, and covered by polyprrole (PPy) layer. The as prepared materials was characterized by UV-vis-spectroscopy (UV-vis), FT-IR, X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) with EDX, high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Sensing of serotonin (5HT) was evaluated electrocatalyst using polypyrrole/glassy carbon electrode (PPy/GCE), polypyrrole/copper oxide/glassy carbon electrode (PPy/Cu 2 O/GCE) and silver/polypyrrole/copper oxide/glassy carbon electrode (Ag/PPy/Cu 2 O/GCE). The Ag/PPy/Cu 2 O/GCE was electrochemically treated in 0.1MPBS solution through cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The peak current response increases linearly with 5-HT concentration from 0.01 to 250 µmol L -1 and the detection limit was found to be 0.0124 μmol L -1 . It exhibits high electrocatalytic activity, satisfactory repeatability, stability, fast response and good selectivity against potentially interfering species, which suggests its potential in the development of sensitive, selective, easy-operation and low-cost serotonin sensor for practical routine analyses. The proposed method is potential to expand the possible applied range of the nanocomposite material for detection of various concerned electro active substances. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy

NASA Astrophysics Data System (ADS)

Ghosh, S. K.

2014-10-01

In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

Hybrid Cu(2)O diode with orientation-controlled C(60) polycrystal.

PubMed

Izaki, Masanobu; Saito, Takamasa; Ohata, Tatsuya; Murata, Kazufumi; Fariza, Binti Mohamad; Sasano, Junji; Shinagawa, Tsutomu; Watase, Seiji

2012-07-25

We report on a hybrid diode composed of a 2.1 eV bandgap p-cupric oxide (Cu2O) semiconductor and fullerene (C60) layer with a face-centered cubic configuration. The hybrid diode has been constructed by electrodeposition of the 500 nm thick Cu2O layer in a basic aqueous solution containing a copper acetate hydrate and lactic acid followed by a vacuum evaporation of the 50 nm thick C60 layer at the evaporation rate from 0.25 to 1.0 Å/s. The C60 layers prepared by the evaporation possessed a face-centered cubic configuration with the lattice constant of 14.19 A, and the preferred orientation changed from random to (111) plane with decrease in the C60 evaporation rate from 1.0 to 0.25 Å/s. The hybrid p-Cu2O/C60 diode showed a rectification feature regardless of the C60 evaporation rate, and both the rectification ratio and forward current density improved with decrease in the C60 evaporation rate. The excellent rectification with the ideality factor of approximately 1 was obtained for the 500 nm thick (111)-Cu2O/50 nm thick (111)-fcc-C60/bathocuproine (BCP) diode at the C60 evaporation rate of 0.25 Å /s. The hybrid Cu2O/C60 diode prepared by stacking the C60 layer at the evaporation rate of 0.25 Å/s revealed the photovoltaic performance of 8.7 × 10(-6)% in conversion efficiency under AM1.5 illumination, and the conversion efficiency changed depending on the C60 evaporation rate.

Sc(2)MgGa(2) and Y(2)MgGa(2).

PubMed

Sahlberg, Martin; Andersson, Yvonne

2009-03-01

Scandium magnesium gallide, Sc(2)MgGa(2), and yttrium magnesium gallide, Y(2)MgGa(2), were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo(2)FeB(2)-type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc(2)MgGa(2 )was determined from single-crystal diffraction intensities and the isostructural Y(2)MgGa(2) was identified from powder diffraction data.

Structural Stability of Diffusion Barriers in Cu/Ru/MgO/Ta/Si

PubMed Central

Hsieh, Shu-Huei; Chen, Wen Jauh; Chien, Chu-Mo

2015-01-01

Various structures of Cu (50 nm)/Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm)/Si were prepared by sputtering and electroplating techniques, in which the ultra-thin trilayer of Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm) is used as the diffusion barrier against the interdiffusion between Cu film and Si substrate. The various structures of Cu/Ru/MgO/Ta/Si were characterized by four-point probes for their sheet resistances, by X-ray diffractometers for their crystal structures, by scanning electron microscopes for their surface morphologies, and by transmission electron microscopes for their cross-section and high resolution views. The results showed that the ultra-thin tri-layer of Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm) is an effective diffusion barrier against the interdiffusion between Cu film and Si substrate. The MgO, and Ta layers as deposited are amorphous. The mechanism for the failure of the diffusion barrier is that the Ru layer first became discontinuous at a high temperature and the Ta layer sequentially become discontinuous at a higher temperature, the Cu atoms then diffuse through the MgO layer and to the substrate at the discontinuities, and the Cu3Si phases finally form. The maximum temperature at which the structures of Cu (50 nm)/Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm)/Si are annealed and still have low sheet resistance is from 550 to 750 °C for the annealing time of 5 min and from 500 to 700 °C for the annealing time of 30 min. PMID:28347099

Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies.

PubMed

Persaud-Sharma, Dharam; Budiansky, Noah; McGoron, Anthony J

2013-01-01

Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effective properties to a binary Mg-Zn alloy. The cytotoxicity of these experimental alloys was evaluated using a tetrazolium based- MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and a lactate dehydrogenase membrane integrity assay (LDH). The MTS assay was performed on extract solutions obtained from a 30-day period of alloy immersion and agitation in simulated body fluid to evaluate the major degradation products eluted from the alloy materials. Human foreskin fibroblast cell growth on the experimental magnesium alloys was evaluated for a 72 hour period, and cell death was quantified by measuring lactate dehydrogenase concentrations. Both Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. The Mg-Zn-Cu alloy was found to completely degrade within 72 hours, resulting in lower human foreskin fibroblast cell viability. The Mg-Zn-Se alloy was shown to be less cytotoxic than both the Mg-Zn-Cu and Mg-Zn alloys.

Biocompatibility Assessment of Novel Bioresorbable Alloys Mg-Zn-Se and Mg-Zn-Cu for Endovascular Applications: In- Vitro Studies

PubMed Central

Budiansky, Noah; McGoron, Anthony J.

2013-01-01

Previous studies have shown that using biodegradable magnesium alloys such as Mg-Zn and Mg-Zn-Al possess the appropriate mechanical properties and biocompatibility to serve in a multitude of biological applications ranging from endovascular to orthopedic and fixation devices. The objective of this study was to evaluate the biocompatibility of novel as-cast magnesium alloys Mg-1Zn-1Cu wt.% and Mg-1Zn-1Se wt.% as potential implantable biomedical materials, and compare their biologically effective properties to a binary Mg-Zn alloy. The cytotoxicity of these experimental alloys was evaluated using a tetrazolium based- MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and a lactate dehydrogenase membrane integrity assay (LDH). The MTS assay was performed on extract solutions obtained from a 30-day period of alloy immersion and agitation in simulated body fluid to evaluate the major degradation products eluted from the alloy materials. Human foreskin fibroblast cell growth on the experimental magnesium alloys was evaluated for a 72 hour period, and cell death was quantified by measuring lactate dehydrogenase concentrations. Both Mg-Zn-Se and Mg-Zn-Cu alloys exhibit low cytotoxicity levels which are suitable for biomaterial applications. The Mg-Zn-Cu alloy was found to completely degrade within 72 hours, resulting in lower human foreskin fibroblast cell viability. The Mg-Zn-Se alloy was shown to be less cytotoxic than both the Mg-Zn-Cu and Mg-Zn alloys. PMID:24058329

Precipitation of a new platelet phase during the quenching of an Al-Zn-Mg-Cu alloy

NASA Astrophysics Data System (ADS)

Zhang, Yong; Weyland, Matthew; Milkereit, Benjamin; Reich, Michael; Rometsch, Paul A.

2016-03-01

A previously undescribed high aspect ratio strengthening platelet phase, herein named the Y-phase, has been identified in a commercial Al-Zn-Mg-Cu alloy. Differential scanning calorimetry indicates that this phase only precipitates at temperature and cooling rate of about 150-250 °C and 0.05-300 K/s, respectively. This precipitate is shown to be responsible for a noticeable improvement in mechanical properties. Aberration corrected scanning transmission electron microscopy demonstrates the minimal thickness (~1.4 nm) precipitate plates are isostructural to those of the T1 (Al2CuLi) phase observed in Al-Cu-Li alloys. Low voltage chemical analysis by energy dispersive X-ray spectroscopy and electron energy loss spectroscopy gives evidence of the spatial partitioning of the Al, Cu and Zn within the Y-phase, as well as demonstrating the incorporation of a small amount of Mg.

Thermoluminescence responses of photon- and electron-irradiated lithium potassium borate co-doped with Cu+Mg or Ti+Mg.

PubMed

Alajerami, Y S M; Hashim, S; Ramli, A T; Saleh, M A; Saripan, M I; Alzimami, K; Min Ung, Ngie

2013-08-01

New glasses Li2CO3-K2CO3-H3BO3 (LKB) co-doped with CuO and MgO, or with TiO2 and MgO, were synthesized by the chemical quenching technique. The thermoluminescence (TL) responses of LKB:Cu,Mg and LKB:Ti,Mg irradiated with 6 MV photons or 6 MeV electrons were compared in the dose range 0.5-4.0 Gy. The standard commercial dosimeter LiF:Mg,Ti (TLD-100) was used to calibrate the TL reader and as a reference in comparison of the TL properties of the new materials. The dependence of the responses of the new materials on (60)Co dose is linear in the range of 1-1000 Gy. The TL yields of both of the co-doped glasses and TLD-100 are greater for electron irradiation than for photon irradiation. The TL sensitivity of LKB:Ti,Mg is 1.3 times higher than the sensitivity of LKB:Cu,Mg and 12 times less than the sensitivity of TLD-100. The new TL dosimetric materials have low effective atomic numbers, good linearity of the dose responses, excellent signal reproducibility, and a simple glow curve structure. This combination of properties makes them suitable for radiation dosimetry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous removal of Cu(II) and Cr(VI) by Mg-Al-Cl layered double hydroxide and mechanism insight.

PubMed

Yue, Xianyang; Liu, Weizhen; Chen, Zuliang; Lin, Zhang

2017-03-01

Mg-Al-Cl layered double hydroxide (Cl-LDH) was prepared to simultaneously remove Cu(II) and Cr(VI) from aqueous solution. The coexisting Cu(II) (20mg/L) and Cr(VI) (40mg/L) were completely removed within 30min by Cl-LDH in a dosage of 2.0g/L; the removal rate of Cu(II) was accelerated in the presence of Cr(VI). Moreover, compared with the adsorption of single Cu(II) or Cr(VI), the adsorption capacities of Cl-LDH for Cu(II) and Cr(VI) can be improved by 81.05% and 49.56%, respectively, in the case of coexisting Cu(II) (200mg/L) and Cr(VI) (400mg/L). The affecting factors (such as solution initial pH, adsorbent dosage, and contact time) have been systematically investigated. Besides, the changes of pH values and the concentrations of Mg 2+ and Al 3+ in relevant solutions were monitored. To get the underlying mechanism, the Cl-LDH samples before and after adsorption were thoroughly characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. On the basis of these analyses, a possible mechanism was proposed. The coadsorption process involves anion exchange of Cr(VI) with Cl - in Cl-LDH interlayer, isomorphic substitution of Mg 2+ with Cu 2+ , formation of Cu 2 Cl(OH) 3 precipitation, and the adsorption of Cr(VI) by Cu 2 Cl(OH) 3 . This work provides a new insight into simultaneous removal of heavy metal cations and anions from wastewater by Cl-LDH. Copyright © 2016. Published by Elsevier B.V.

X-ray photoemission studies of Zn doped Cu 1- xTl xBa 2Ca 2Cu 3- yZn yO 10- δ ( y = 0, 2.65) superconductors

NASA Astrophysics Data System (ADS)

Khan, Nawazish A.; Mumtaz, M.; Ahadian, M. M.; Iraji-zad, Azam

2007-03-01

The X-ray photoemission (XPS) measurements of Cu 1- xTl xBa 2Ca 2Cu 3- yZn yO 10- δ ( y = 0, 2.65) superconductors have been performed and compared. These studies revealed that the charge state of thallium in the Cu 0.5Tl 0.5Ba 2O 4- δ charge reservoir layer in Zn doped samples is Tl 1+, while it is a mix of Tl 1+ and Tl 2+ in Zn free samples. The binding energy of Ba atoms in the Zn doped samples is shifted to higher energy, which when considered along with the presence of Tl 1+ suggested that it more efficiently directed the carriers to ZnO 2 and CuO 2 planes. The evidence of improved inter-plane coupling witnessed in X-ray diffraction is also confirmed by XPS measurements of Ca atoms in the Zn doped samples. The shift of the valance band spectrum in these Zn doped samples to higher energies suggested that the electrons at the top edge of the valance band were tied to a higher binding energy (relative to samples without Zn doping), which most likely resulted in a much lower energy state of the system in the superconducting state. The stronger superconducting state arising out of these effects is witnessed in the form of increased Tc( R = 0), Jc and the extent of diamagnetism in the final compound.

Control of Co content and SOFC cathode performance in Y1-ySr2+yCu3-xCoxO7+δ

NASA Astrophysics Data System (ADS)

Šimo, F.; Payne, J. L.; Demont, A.; Sayers, R.; Li, Ming; Collins, C. M.; Pitcher, M. J.; Claridge, J. B.; Rosseinsky, M. J.

2014-11-01

The electrochemical performance of the layered perovskite YSr2Cu3-xCoxO7+δ, a potential solid oxide fuel cell (SOFC) cathode, is improved by increasing the Co content from x = 1.00 to a maximum of x = 1.30. Single phase samples with x > 1.00 are obtained by tuning the Y/Sr ratio, yielding the composition Y1-ySr2+yCu3-xCoxO7+δ (where y ≤ 0.05). The high temperature structure of Y0.95Sr2.05Cu1.7Co1.3O7+δ at 740 °C is characterised by powder neutron diffraction and the potential of this Co-enriched material as a SOFC cathode is investigated by combining AC impedance spectroscopy, four-probe DC conductivity and powder XRD measurements to determine its electrochemical properties along with its thermal stability and compatibility with a range of commercially available electrolytes. The material is shown to be compatible with doped ceria electrolytes at 900 °C.

Electronic properties of Y-Ba-Cu-O superconductors as seen by Cu and O NMR/NQR

NASA Technical Reports Server (NTRS)

Brinkmann, D.

1995-01-01

Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) allow the investigation of electronic properties at the atomic level. We will report on such studies of typical members of the the Y-Ba-Cu-O family such as YBa2Cu30(6 + x) (1-2-3-(6 + x)), YBa2Cu4O8 (1-2-4) and Y2Ba4Cu7015 (2-4-7) with many examples of recent work performed in our laboratory. In particular, we will deal with Knight shift and relaxation studies of copper and oxygen. We will discuss important issues of current studies such as: (1) Existence of a common electronic spin-susceptibility in the planes (and perhaps in the chains) of 1-2-4; (2) Strong evidence for the existence of a pseudo spin-gap of the antiferromagnetic fluctuations in 1-2-4 and 2-4-7; (3) Evidence for d-wave pairing in 1-2-4; (4) Strong coupling of inequivalent Cu-O planes in 2-4-7 and possible origin for the high Tc value of this compound; and (5) The possibility to describe NMR data in the framework of a charge-excitation picture.

A 10 GHz Y-Ba-Cu-O/GaAs hybrid oscillator proximity coupled to a circular microstrip patch antenna

NASA Technical Reports Server (NTRS)

Rohrer, Norman J.; Richard, M. A.; Valco, George J.; Bhasin, Kul B.

1993-01-01

A 10 GHz hybrid Y-Ba-Cu-O / GaAs microwave oscillator proximity coupled to a circular microstrip antenna was designed, fabricated and characterized. The oscillator was a reflection mode type using a GaAs MESFET as the active element. The feedline, transmission lines, RF chokes, and bias lines were all fabricated from YBa2Cu3O(7-x) superconducting thin films on a 1 cm x 1 cm lanthanum aluminate substrate. The output feedline of the oscillator was wire bonded to a superconducting feedline on a second 1 cm x 1 cm lanthanum aluminate substrate, which was in turn proximity coupled to a circular microstrip patch antenna. Antenna patterns from this active patch antenna and the performance of the oscillator measured at 77 K are reported. The oscillator had a maximum output power of 11.5 dBm at 77 K, which corresponded to an efficiency of 10 percent. In addition, the efficiency of the microstrip patch antenna together with its high temperature superconducting feedline was measured from 85 K to 30 K and was found to be 71 percent at 77 4 increasing to a maximum of 87.4 percent at 30 K.

Investigation of copper (Cu2+) adsorption performances and gamma radiation dose effect of polymeric hydrogel

NASA Astrophysics Data System (ADS)

Hassan, Safia; Yasin, Tariq; Imran, Zahid; Batool, Syeda Sitwat

2018-02-01

In present study, series of gamma irradiated poly(acrylic acid)/Penytriethoxytrisilane (PTES) based hydrogels were synthesized. The hydrogels were used for the adsorption of Cu2+ from the aqueous solution. Batch adsorption experiments were performed by varying contact time (0-10 hours), pH value (2-6), hydrogels weight (15-155 mg) and initial Cu2+ concentration (0.003-90 mg/L). The results indicated that lowering the gamma irradiation dose (30-15 kGy) and PTES amount (1.65-0.83 μmol) into hydrogel polymeric networks, improved the initial rate of adsorption and final adsorption capacity of hydrogel for Cu2+. AA40/15 had 143.4mg/g Cu2+ adsorption capacity higher than AA80/30 which is 106.0mg/g. Hydrogels exhibited maximum o adsorption capacity for Cu2+ within a wide pH range. All adsorption data was described by the pseudo—first order and second order kinetic model equations and isotherm data by Langmuir model. FTIR spectra analysis before and after adsorption of Cu2+ on the AA hydrogels gave detail analysis of adsorption mechanism. The behavior of adsorption expressed that the enhanced adsorption capacity was due to the porous structure and e presence of functional groups onto surface of adsorbate. It is expected this polymeric hydrogel has potential to work as alternative biomedical sorbents and environmental use as pH altered.

Effect of dopants on the TL response of the new LiF:Mg,Cu,Ag material

NASA Astrophysics Data System (ADS)

Yahyaabadi, A.; Torkzadeh, F.; Rezaei-Ochbelagh, D.; Hosseini Pooya, M.

2018-07-01

The new TL LiF:Mg,Cu,Ag material was prepared and investigated in this study. The TL intensity of LiF:Mg,Cu,Ag is strongly dependent on the concentration of dopants and the preparation procedure. Any small change in these factors can cause alterations in TL response. In this study, the influence of Cu and Ag concentrations on the response of the LiF:Mg,Cu,Ag sample was investigated and showed that the height of the low, main and high temperature peaks changes with Ag concentration. Their intensities increased with increasing Ag concentration to a maximum value and decreased with higher Ag concentration. It was also found that Cu concentration less than 0.05 mol% influences the maximum peak height and TL intensity. The optimum Cu and Ag concentrations were found to be 0.05 and 0.1 mol% at 1005 °C QT, respectively. The role of dopants in LiF:Mg,Cu,Ag material was also investigated. The results showed that presence of three dopants is important for having material with sensitivity higher than LiF:Mg,Ti. The Mg dopant plays a crucial role in the formation of the trapping center and the position of the main dosimetric peak.

Magnetic, Electric and Optical Properties of Mg-Substituted Ni-Cu-Zn Ferrites

NASA Astrophysics Data System (ADS)

Kabbur, S. M.; Ghodake, U. R.; Kambale, Rahul C.; Sartale, S. D.; Chikhale, L. P.; Suryavanshi, S. S.

2017-10-01

The Ni0.25- x Mg x Cu0.30Zn0.45Fe2O4 ( x = 0.00 mol, 0.05 mol, 0.10 mol, 0.15 mol, 0.20 mol and 0.25 mol) magnetic oxide system was prepared by a sol-gel auto-combustion method using glycine as a fuel. X-ray diffraction study reveals the formation of pure spinel lattice symmetry along with the presence of a small fraction of unreacted Fe2O3 phase as a secondary phase due to incomplete combustion reaction between fuel and oxidizer. The lattice constant ( a) was found to decrease with the increase of Mg2+ content; the average crystallite size ( D) is observed in the range of 26.78-33.14 nm. At room temperature, all the samples show typical magnetic hysteresis loops with the decrease of magnetic moment ( n B) of Ni-Cu-Zn ferrites with the increase of Mg2+ content. The intrinsic vibrational absorption bands for the tetrahedral and octahedral sites of the spinel structure were confirmed by infrared (IR) spectroscopy. The optical parameters such as refractive index ( η), velocity of IR waves ( v) and jump rates ( J 1, J 2, J) were studied and found to be dependent on the variation of the lattice constant. The Curie temperature ( T c) of Ni-Cu-Zn mixed ferrite was found to decrease with Mg2+ addition. The composition x = 0.15 mol.% with a low dielectric loss tangent of 2% seems to have potential for multilayer chip inductor applications at a wide range of frequencies.

Preparation of Cu2O-Reduced Graphene Nanocomposite Modified Electrodes towards Ultrasensitive Dopamine Detection

PubMed Central

He, Quanguo; Liu, Jun; Liu, Xiaopeng; Li, Guangli; Deng, Peihong; Liang, Jing

2018-01-01

Cu2O-reduced graphene oxide nanocomposite (Cu2O-RGO) was used to modify glassy carbon electrodes (GCE), and applied for the determination of dopamine (DA). The microstructure of Cu2O-RGO nanocomposite material was characterized by scanning electron microscope. Then the electrochemical reduction condition for preparing Cu2O-RGO/GCE and experimental conditions for determining DA were further optimized. The electrochemical behaviors of DA on the bare electrode, RGO- and Cu2O-RGO-modified electrodes were also investigated using cyclic voltammetry in phosphate-buffered saline solution (PBS, pH 3.5). The results show that the oxidation peaks of ascorbic acid (AA), dopamine (DA), and uric acid (UA) could be well separated and the peak-to-peak separations are 204 mV (AA-DA) and 144 mV (DA-UA), respectively. Moreover, the linear response ranges for the determination of 1 × 10−8 mol/L~1 × 10−6 mol/L and 1 × 10−6 mol/L~8 × 10−5 mol/L with the detection limit 6.0 × 10−9 mol/L (S/N = 3). The proposed Cu2O-RGO/GCE was further applied to the determination of DA in dopamine hydrochloride injections with satisfactory results. PMID:29329206

Magnetic anisotropy and magnetization reversal in Co/Cu multilayers nanowires

NASA Astrophysics Data System (ADS)

Ahmad, Naeem; Chen, J. Y.; Shi, D. W.; Iqbal, Javed; Han, Xiufeng

2012-04-01

The Co/Cu multilayer nanowires fabricated in an array using anodized aluminum oxide (AAO) template by electrodeposition method, have been investigated. It has been observed that the magnetization reversal mode and magnetic anisotropy depend upon the Co and Cu layer thicknesses. Magnetization reversal occurs by curling mode at around Co = 400 nm and Cu = 10 nm, while for Co = 30 nm and Cu = 60 nm, magnetization reversal occurs by nucleation mode. A change of magnetic anisotropy from out of plane to in plane is observed when thickness of Cu layer tCu = 60 nm and that of Co tCo = 30 nm. Magnetic anisotropy is lost when thickness of the Co layer tCo = 400 nm and that of Cu tCu= 10 nm. Magnetic properties have been explained by the competition among shape anisotropy, magnetostatic interactions and magnetocrystalline anisotropy. Magnetic properties can be tuned accordingly depending upon the thickness of the Co and Cu nanodisks.

Investigation on hydrogenation performance of Mg{sub 2}Ni+10 wt.% NbN composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Xin; Han, Shumin; State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004

2015-01-15

The Mg{sub 2}Ni+10 wt.% NbN composite was prepared by mechanical milling and its hydrogen absorption/desorption properties and microstructure were systematically investigated. XRD results indicated that NbN was stable during ball milling process while partly decomposed into NbN{sub 0.95} and NbH during hydriding/dehydriding cycles irreversibly. The composite exhibited excellent hydrogenation/dehydrogenation kinetics performance with 2.71 wt.% hydrogen absorbed in 60 s at 423 K and 0.81 wt.% hydrogen released in 2 h at 523 K, respectively. The H diffusion constant of the composite reached 14.98×10{sup −5} s{sup −1} which was more than twice increased than that of pure Mg{sub 2}Ni powder. Themore » superior hydrogen storage properties of the composite were ascribed to the refined grain size and abundant N-defect points provided by NbN and NbN{sub 0.95} in the composite. - Graphical abstract: The Mg{sub 2}Ni+10 wt.% NbN composite displays improvements on particle size distribution as well as hydrogen storage properties compared with that of pure Mg{sub 2}Ni. - Highlights: • NbN is introduced into Mg{sub 2}Ni hydride by Ar protected ball-milling. • Surfaces of the additive NbN particle are reduced by Mg{sub 2}NiH{sub 4}. • Hydrogenation kinetic property at 423 K is double improved. • Dehydrogenation capacity at 523 K of composites is beyond double improved.« less

Matrix effects in ion-induced emission as observed in Ne collisions with Cu-Mg and Cu-Al alloys

NASA Technical Reports Server (NTRS)

Ferrante, J.; Pepper, S. V.

1983-01-01

Ion induced Auger electron emission is used to study the surfaces of Al, Mg, Cu - 10 at. % Al, Cu - 19.6 at. % Al, and Cu - 7.4 at. % Mg. A neon (Ne) ion beam whose energy is varied from 0.5 to 3 keV is directed at the surface. Excitation of the lighter Ne occurs by the promotion mechanism of Barat and Lichten in asymmetric collisions with Al or Mg atoms. Two principal Auger peaks are observed in the Ne spectrum: one at 22 eV and one at 25 eV. Strong matrix effects are observed in the alloys as a function of energy in which the population of the second peak is greatly enhanced relative to the first over the pure materials. For the pure material over this energy range this ratio is 1.0. For the alloys it can rise to the electronic structure of alloys and to other surface tools such as secondary ion mass spectroscopy.

On the Functionality of Complex Intermetallics: Frustration, Chemical Pressure Relief, and Potential Rattling Atoms in Y11Ni60C6.

PubMed

Guo, Yiming; Fredrickson, Daniel C

2016-10-17

Intermetallic carbides provide excellent model systems for exploring how frustration can shape the structures and properties of inorganic materials. Combinations of several metals with carbon can be designed in which the formation of tetrahedrally close-packed (TCP) intermetallics conflicts with the C atoms' requirement of trigonal prismatic or octahedral coordination environments, as offered by the simple close-packings (SCP) of equally sized spheres. In this Article, we explore the driving forces that lead to the coexistence of these incompatible arrangements in the Yb 11 Ni 60 C 6 -type compound Y 11 Ni 60 C 6 (cI154), as well as potential consequences of this intergrowth for the phase's physical properties. Our focus begins on the structure's SCP regions, which appear as C-stuffed versions of a AuCu 3 -type YNi 3 phase that is not observed on its own in the Y-Ni system. DFT-Chemical Pressure (DFT-CP) calculations on this hypothetical YNi 3 phase reveal large negative pressures within the Ni sublattice, as it is stretched to accommodate the size requirements of the Y atoms. In the Y 11 Ni 60 C 6 structure, two structural mechanisms for addressing these CP issues appear: the incorporation of interstitial C atoms, and the presence of interfaces with CaCu 5 -type domains. The relative roles of these two mechanisms are investigated with the CP analysis on a hypothetical YNi 3 C x series of C-stuffed AuCu 3 -type phases, the Y-Ni sublattice of Y 11 Ni 60 C 6 , and finally the full Y 11 Ni 60 C 6 structure. Through these calculations, the C atoms appear to play the roles of relieving positive Y CPs and supporting relaxation at the AuCu 3 -type/CaCu 5 -type interfaces, where the cancellation occurs between opposite CPs experienced by the Y atoms in the two parent structures (following the epitaxial stabilization mechanism). The CP analysis of Y 11 Ni 60 C 6 also highlights a sublattice of Y and Ni atoms with large negative CPs (and thus the potential for soft

Glassy formation ability, magnetic properties and magnetocaloric effect in Al27Cu18Er55 amorphous ribbon

NASA Astrophysics Data System (ADS)

Li, Lingwei; Xu, Chi; Yuan, Ye; Zhou, Shengqiang

2018-05-01

In this work, we have fabricated the Al27Cu18Er55 amorphous ribbon with good glassy formation ability by melt-spinning technology. A broad paramagnetic (PM) to ferromagnetic (FM) transition (second ordered) together with a large reversible magnetocaloric effect (MCE) in Al27Cu18Er55 amorphous ribbon was observed around the Curie temperature TC ∼ 11 K. Under the magnetic field change (ΔH of 0-7 T, the values of MCE parameter of the maximum magnetic entropy change (-ΔSMmax) and refrigerant capacity (RC) for Al27Cu18Er55 amorphous ribbon reach 21.4 J/kg K and 599 J/kg, respectively. The outstanding glass forming ability as well as the excellent magneto-caloric properties indicate that Al27Cu18Er55 amorphous could be a good candidate for low temperature magnetic refrigeration.

Glassy carbon electrode modified with polyanilne/ethylenediamine for detection of copper ions

NASA Astrophysics Data System (ADS)

Patil, Harshada K.; Deshmukh, Megha A.; Bodkhe, Gajanan A.; Shirsat, Mahendra D.

2018-05-01

Increasing water pollution is having high concern, since it creates the threats to all leaving organisms of existence. Industrial sewages have not only polluted the main stream lines of water, also the ground level water is having serious contaminations. Heavy metal ions are the pollutants which are not degradable and can be accumulated on living things ultimately the excess accumulation results into the serious concerns. Therefore, it is necessary to develop the sensors which can detect the heavy metal ions up to its maximum contamination limits. Conducting polymers are the materials which possess large application spectra. This investigation reports the electrochemically synthesized polyaniline (PANI) for modification of glassy carbon electrode (GCE). Ethylenediamine (EDA) - chelating ligand used for the modification of polyaniline so as to inculcate the selectivity toward copper ions Cu (II). The electrochemical cyclic voltammetry (CV) was used for the study of redox characteristics of PANI and influence of EDA modification. The result of CV has shown the reduced oxidation and reduction peak currents after modification indicating the domination of EDA. GCE modified with PANI/EDA was then employed for the detection of divalent copper ions and have shown the affinity toward Cu ions. The detection limit achieved was equal to 10mg/lit.

Shallow Acceptor State in Mg-Doped CuAlO2 and Its Effect on Electrical and Optical Properties: An Experimental and First-Principles Study.

PubMed

Liu, Ruijian; Li, Yongfeng; Yao, Bin; Ding, Zhanhui; Jiang, Yuhong; Meng, Lei; Deng, Rui; Zhang, Ligong; Zhang, Zhenzhong; Zhao, Haifeng; Liu, Lei

2017-04-12

Shallow acceptor states in Mg-doped CuAlO 2 and their effect on structural, electrical, and optical properties are investigated by combining first-principles calculations and experiments. First-principles calculations demonstrate that Mg substituting at the Al site in CuAlO 2 plays the role of shallow acceptor and has a low formation energy, suggesting that Mg doping can increase hole concentration and improve the conductivity of CuAlO 2 . Hall effect measurements indicate that the hole concentration of the Mg-doped CuAlO 2 thin film is 2 orders of magnitude higher than that of undoped CuAlO 2 . The best room temperature conductivity of 8.0 × 10 -2 S/cm is obtained. A band gap widening is observed in the optical absorption spectra of Mg-doped CuAlO 2 , which is well supported by the results from first-principles electronic structure calculations.

L10 FePtCu bit patterned media

NASA Astrophysics Data System (ADS)

Brombacher, C.; Grobis, M.; Lee, J.; Fidler, J.; Eriksson, T.; Werner, T.; Hellwig, O.; Albrecht, M.

2012-01-01

Chemically ordered 5 nm-thick L10 FePtCu films with strong perpendicular magnetic anisotropy were post-patterned by nanoimprint lithography into a dot array over a 3 mm-wide circumferential band on a 3 inch Si wafer. The dots with a diameter of 30 nm and a center-to-center pitch of 60 nm appear as single domain and reveal an enhanced switching field as compared to the continuous film. We demonstrate successful recording on a single track using shingled writing with a conventional hard disk drive write/read head.

Extended-release dexmethylphenidate 30 mg/d versus 20 mg/d: duration of attention, behavior, and performance benefits in children with attention-deficit/hyperactivity disorder.

PubMed

Silva, Raul R; Brams, Matthew; McCague, Kevin; Pestreich, Linda; Muniz, Rafael

2013-01-01

This study aimed to compare the effects of dexmethylphenidate (D-MPH) extended-release (ER) 30 mg and D-MPH-ER 20 mg on attention, behavior, and performance in children with attention-deficit/hyperactivity disorder. In a randomized, double-blind, 3-period-by-3-treatment, crossover study, children aged 6 to 12 years with attention-deficit/hyperactivity disorder stabilized on methylphenidate (40-60 mg/d) or D-MPH (20-30 mg/d) received D-MPH-ER 20 mg/d, 30 mg/d, and placebo for 7 days each (final dose of each treatment period administered in a laboratory classroom). Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) Combined (Attention and Deportment) rating scale and Permanent Product Measure of Performance (PERMP) math test assessments were conducted at baseline and 3, 6, 9, 10, 11, and 12 hours postdose. A total of 165 children (94 boys; mean age, 9.6 years) were randomized (162 included in intent-to-treat analyses). Significant improvements were noted for D-MPH-ER 30 mg over D-MPH-ER 20 mg at various late time points on the SKAMP scales (Combined scores at 9, 10, 11, and 12 hours postdose; Attention scores at 10, 11, and 12 hours postdose; deportment scores at 9 and 12 hours postdose). The PERMP math test-attempted and -correct scores (change from predose) were significantly higher with D-MPH-ER 30 mg than with D-MPH-ER 20 mg at 10, 11, and 12 hours postdose. Both D-MPH-ER doses were superior to placebo at all time points. D-MPH-ER 30 mg was superior to D-MPH-ER 20 mg at later time points in the day, suggesting that higher doses of D-MPH-ER may be more effective later in the day.

Glassy behavior of diluted Cu-Zn ferrites

NASA Astrophysics Data System (ADS)

Akhter, Shahida; Hakim, M. A.; Hoque, S. M.; Mathieu, R.; Nordblad, P.

2018-04-01

The magnetic behavior of Zn substituted Cu-Zn spinel ferrites having chemical formula Cu1-xZnxFe2O4 (x = 0.7, 0.8, 0.9 and 1.0) has been studied by SQUID magnetometry, by means of magnetic hysteresis, field-cooled (FC) and zero-field-cooled (ZFC) magnetization, memory effect and low field ac susceptibility measurements. These measurements suggest that the ferrimagnetic phase of the x ≤ 0.8 samples is gradually turned into a spin glass (x ≥ 0.9). The compound with x = 0.9 exhibits the typical dynamical behavior of spin glasses, with indication of aging, rejuvenation and memory effects. The evolution of the magnetic properties of Cu-Zn spinel ferrites with substitution of Zn for Cu is discussed.

Dielectric properties of (CuO, CaO2, and BaO)y/CuTl-1223 composites

NASA Astrophysics Data System (ADS)

Mumtaz, M.; Kamran, M.; Nadeem, K.; Jabbar, Abdul; Khan, Nawazish A.; Saleem, Abida; Tajammul Hussain, S.; Kamran, M.

2013-07-01

We synthesized (CuO, CaO2, and BaO)y/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ (y = 0, 5%, 10%, 15%) composites by solid-state reaction and characterized them by x-ray diffraction, scanning electron microscopy, dc-resistivity, and Fourier transform infrared spectroscopy. Frequency and temperature dependent dielectric properties, such as real and imaginary parts of the dielectric constant, dielectric loss, and ac-conductivity of these composites were studied by capacitance and conductance measurements as a function of frequency (10 kHz to 10 MHz) and temperature (78 to 300 K). X-ray diffraction analysis reveals that the characteristic behavior of the superconductor phase and the structure of Cu0.5Tl0.5Ba2Ca2Cu3O10-δ are nearly undisturbed by doping with nanoparticles. Scanning electron microscopy images show the improvement in the intergranular linking between the superconducting grains occurring with increasing nanoparticle concentration. Microcracks are healed up with these nanoparticles, and superconducting volume fraction is also increased. Dielectric properties of these composites strongly depend on the frequency and temperature. Zero resistivity critical temperature and dielectric properties show opposite trends with the addition of nanoparticles to the Cu0.5Tl0.5Ba2Ca2Cu3O10-δ superconductor matrix.

Growth and characterization of thin Cu-phthalocyanine films on MgO(001) layer for organic light-emitting diodes.

PubMed

Bae, Yu Jeong; Lee, Nyun Jong; Kim, Tae Hee; Cho, Hyunduck; Lee, Changhee; Fleet, Luke; Hirohata, Atsufumi

2012-11-26

Surface morphology and thermal stability of Cu-phthalocyanine (CuPc) films grown on an epitaxially grown MgO(001) layer were investigated by using atomic force microscope and X-ray diffractometer. The (002) textured β phase of CuPc films were prepared at room temperature beyond the epitaxial MgO/Fe/MgO(001) buffer layer by the vacuum deposition technique. The CuPc structure remained stable even after post-annealing at 350°C for 1 h under vacuum, which is an important advantage of device fabrication. In order to improve the device performance, we investigated also current-voltage-luminescence characteristics for the new top-emitting organic light-emitting diodes with different thicknesses of CuPc layer.

Adaptation to chronic MG132 reduces oxidative toxicity by a CuZnSOD-dependent mechanism

PubMed Central

Leak, Rehana K.; Zigmond, Michael J.; Liou, Anthony K. F.

2010-01-01

To study whether and how cells adapt to chronic cellular stress, we exposed PC12 cells to the proteasome inhibitor MG132 (0.1 μM) for 2 weeks and longer. This treatment reduced chymotrypsin-like proteasome activity by 47% and was associated with protection against both 6-hydroxydopamine (6-OHDA, 100 μM) and higher dose MG132 (40 μM). Protection developed slowly over the course of the first 2 weeks of exposure and was chronic thereafter. There was no change in total glutathione levels after MG132. Buthionine sulfoximine (100 μM) reduced glutathione levels by 60%, but exacerbated 6-OHDA toxicity to the same extent in both MG132-treated and control cells and failed to reduce MG132-induced protection. Chronic MG132 resulted in elevated antioxidant proteins CuZn superoxide dismutase (SOD, +55%), MnSOD (+21%), and catalase (+15%), as well as chaperone heat shock protein 70 (+42%). Examination of SOD enzyme activity revealed higher levels of CuZnSOD (+40%), with no change in MnSOD. We further assessed the mechanism of protection by reducing CuZnSOD levels with two independent siRNA sequences, both of which successfully attenuated protection against 6-OHDA. Previous reports suggested that artificial overexpression of CuZnSOD in dopaminergic cells is protective. Our data complement such observations, revealing that dopaminergic cells are also able to use endogenous CuZnSOD in self-defensive adaptations to chronic stress, and that they can even do so in the face of extensive glutathione loss. PMID:18466318

Synthesis and characterization of Chitosan-CuO-MgO polymer nanocomposites

NASA Astrophysics Data System (ADS)

Praffulla, S. R.; Bubbly, S. G.

2018-05-01

In the present work, we have synthesized Chitosan-CuO-MgO nanocomposites by incorporating CuO and MgO nanoparticles in chitosan matrix. Copper oxide and magnesium oxide nanoparticles synthesized by precipitation method were characterized by X-ray diffraction and the diffraction patterns confirmed the monoclinic and cubic crystalline structures of CuO and MgO nanoparticles respectively. Chitosan-CuO-MgO composite films were prepared using solution- cast method with different concentrations of CuO and MgO nanoparticles (15 - 50 wt % with respect to chitosan) and characterized by XRD, FTIR and UV-Vis spectroscopy. The X-ray diffraction pattern shows that the crystallinity of the chitosan composite increases with increase in nanoparticle concentration. FTIR spectra confirm the chemical interaction between chitosan and metal oxide nanoparticles (CuO and MgO). UV absorbance of chitosan nanocomposites were up to 17% better than pure chitosan, thus confirming its UV shielding properties. The mechanical and electrical properties of the prepared composites are in progress.

Vapor annealing synthesis of non-epitaxial MgB2 films on glassy carbon

NASA Astrophysics Data System (ADS)

Baker, A. A.; Bayu Aji, L. B.; Bae, J. H.; Stavrou, E.; Steich, D. J.; McCall, S. K.; Kucheyev, S. O.

2018-05-01

We describe the fabrication and characterization of 25–800 nm thick MgB2 films on glassy carbon substrates by Mg vapor annealing of sputter-deposited amorphous B films. Results demonstrate a critical role of both the initial B film thickness and the temperature–time profile on the microstructure, elemental composition, and superconducting properties of the resultant MgB2 films. Films with thicknesses of 55 nm and below exhibit a smooth surface, with a roughness of 1.1 nm, while thicker films have surface morphology consisting of elongated nano-crystallites. The suppression of the superconducting transition temperature for thin films scales linearly with the oxygen impurity concentration and also correlates with the amount of lattice disorder probed by Raman scattering. The best results are obtained by a rapid (12 min) anneal at 850 °C with large temperature ramp and cooling rates of ∼540 °C min‑1. Such fast processing suppresses the deleterious oxygen uptake.

Japanese Language and Culture: 10-3Y, 20-3Y, 30-3Y. 3-Year Program Guide to Implementation

ERIC Educational Resources Information Center

Alberta Education, 2009

2009-01-01

This guide to implementation is intended to support the Japanese Language and Culture 10-3Y, 20-3Y, 30-3Y Program of Studies. It was developed primarily for teachers, yet it includes information that may be useful for administrators and other stakeholders in their efforts to plan for and implement the new Japanese program of studies. Familiarity…

46 CFR 91.60-30 - Safety Management Certificate.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Safety Management Certificate. 91.60-30 Section 91.60-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS INSPECTION AND CERTIFICATION Certificates Under International Convention for Safety of Life at Sea, 1974 § 91.60-30 Safety Management Certificate. All...

Biodegradable Mg-Cu alloys with enhanced osteogenesis, angiogenesis, and long-lasting antibacterial effects

PubMed Central

Liu, Chen; Fu, Xuekun; Pan, Haobo; Wan, Peng; Wang, Lei; Tan, Lili; Wang, Kehong; Zhao, Ying; Yang, Ke; Chu, Paul K.

2016-01-01

A series of biodegradable Mg-Cu alloys is designed to induce osteogenesis, stimulate angiogenesis, and provide long-lasting antibacterial performance at the same time. The Mg-Cu alloys with precipitated Mg2Cu intermetallic phases exhibit accelerated degradation in the physiological environment due to galvanic corrosion and the alkaline environment combined with Cu release endows the Mg-Cu alloys with prolonged antibacterial effects. In addition to no cytotoxicity towards HUVECs and MC3T3-E1 cells, the Mg-Cu alloys, particularly Mg-0.03Cu, enhance the cell viability, alkaline phosphatase activity, matrix mineralization, collagen secretion, osteogenesis-related gene and protein expressions of MC3T3-E1 cells, cell proliferation, migration, endothelial tubule forming, angiogenesis-related gene, and protein expressions of HUVECs compared to pure Mg. The favorable osteogenesis and angiogenesis are believed to arise from the release of bioactive Mg and Cu ions into the biological environment and the biodegradable Mg-Cu alloys with osteogenesis, angiogenesis, and long-term antibacterial ability are very promising in orthopedic applications. PMID:27271057

Growth and characterization of thin Cu-phthalocyanine films on MgO(001) layer for organic light-emitting diodes

PubMed Central

2012-01-01

Surface morphology and thermal stability of Cu-phthalocyanine (CuPc) films grown on an epitaxially grown MgO(001) layer were investigated by using atomic force microscope and X-ray diffractometer. The (002) textured β phase of CuPc films were prepared at room temperature beyond the epitaxial MgO/Fe/MgO(001) buffer layer by the vacuum deposition technique. The CuPc structure remained stable even after post-annealing at 350°C for 1 h under vacuum, which is an important advantage of device fabrication. In order to improve the device performance, we investigated also current-voltage-luminescence characteristics for the new top-emitting organic light-emitting diodes with different thicknesses of CuPc layer. PMID:23181826

Phase conversion from hexagonal CuS(y)Se(1-y) to cubic Cu(2-x)S(y)Se(1-y): composition variation, morphology evolution, optical tuning, and solar cell applications.

PubMed

Xu, Jun; Yang, Xia; Yang, Qingdan; Zhang, Wenjun; Lee, Chun-Sing

2014-09-24

In this work, we report a simple and low-temperature approach for the controllable synthesis of ternary Cu-S-Se alloys featuring tunable crystal structures, compositions, morphologies, and optical properties. Hexagonal CuS(y)Se(1-y) nanoplates and face centered cubic (fcc) Cu(2-x)S(y)Se(1-y) single-crystal-like stacked nanoplate assemblies are synthesized, and their phase conversion mechanism is well investigated. It is found that both copper content and chalcogen composition (S/Se atomic ratio) of the Cu-S-Se alloys are tunable during the phase conversion process. Formation of the unique single-crystal-like stacked nanoplate assemblies is resulted from oriented stacking coupled with the Ostwald ripening effect. Remarkably, optical tuning for continuous red shifts of both the band-gap absorption and the near-infrared localized surface plasmon resonance are achieved. Furthermore, the novel Cu-S-Se alloys are utilized for the first time as highly efficient counter electrodes (CEs) in quantum dot sensitized solar cells (QDSSCs), showing outstanding electrocatalytic activity for polysulfide electrolyte regeneration and yielding a 135% enhancement in power conversion efficiency (PCE) as compared to the noble metal Pt counter electrode.

Effect of the addition of B{sub 2}O{sub 3} and BaO-B{sub 2}O{sub 3}-SiO{sub 2} glasses on the microstructure and dielectric properties of giant dielectric constant material CaCu{sub 3}Ti{sub 4}O{sub 12}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shri Prakash, B.; Varma, K.B.R.

2007-06-15

The effect of the addition of glassy phases on the microstructure and dielectric properties of CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) ceramics was investigated. Both single-component (B{sub 2}O{sub 3}) and multi-component (30 wt% BaO-60 wt% B{sub 2}O{sub 3}-10 wt% SiO{sub 2} (BBS)) glass systems were chosen to study their effect on the density, microstructure and dielectric properties of CCTO. Addition of an optimum amount of B{sub 2}O{sub 3} glass facilitated grain growth and an increase in dielectric constant. However, further increase in the B{sub 2}O{sub 3} content resulted in its segregation at the grain boundaries associated with a reduction in themore » grain size. In contrast, BBS glass addition resulted in well-faceted grains and increase in the dielectric constant and decrease in the dielectric loss. An internal barrier layer capacitance (IBLC) model was invoked to correlate the dielectric constant with the grain size in these samples. - Graphical abstract: Scanning electron micrograph of 30 wt% BaO-60 wt% B{sub 2}O{sub 3}-10 wt% SiO{sub 2} (BBS) glass-added CaCu{sub 3}Ti{sub 4}O{sub 12} ceramic on sintering.« less

Relationship between morphologies and orientations of Cu{sub 6}Sn{sub 5} grains in Sn3.0Ag0.5Cu solder joints on different Cu pads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Yanhong, E-mail: tianyh@hit.edu.cn; Zhang, Rui; Hang, Chunjin

2014-02-15

The morphologies and orientations of Cu{sub 6}Sn{sub 5} intermetallic compounds in the Sn3.0Ag0.5Cu solder joints both on polycrystalline and single crystal Cu pads under different peak reflow temperatures and times above liquids were investigated. The relationship between Cu{sub 6}Sn{sub 5} grain orientations and morphologies was clarified. At the interface of Sn3.0Ag0.5Cu/polycrystalline Cu pad, scalloped Cu{sub 6}Sn{sub 5} intermetallic compounds formed at 250 °C and roof shape Cu{sub 6}Sn{sub 5} formed at 300 °C. Both scalloped Cu{sub 6}Sn{sub 5} and roof shape Cu{sub 6}Sn{sub 5} had a preferred orientation of (0001) plane being parallel to polycrystalline Cu pad surface. Besides, themore » percentage of large angle grain boundaries increased as the peak reflow temperature rose. At the interface of Sn3.0Ag0.5Cu/(111) single crystal Cu pad, the Cu{sub 6}Sn{sub 5} intermetallic compounds were mainly scallop-type at 250 °C and were prism type at 300 °C. The prismatic Cu{sub 6}Sn{sub 5} grains grew along the three preferred directions with the inter-angles of 60° on (111) single crystal Cu pad while along two perpendicular directions on (100) single crystal Cu pad. The orientation relationship between Cu{sub 6}Sn{sub 5} grains and the single crystal Cu pads was investigated by electron backscatter diffraction technology. In addition, two types of hollowed Cu{sub 6}Sn{sub 5} intermetallic compounds were found inside the joints of polycrystalline Cu pads. The long hexagonal Cu{sub 6}Sn{sub 5} strips were observed in the joints reflowing at 250 °C while the hollowed Cu{sub 6}Sn{sub 5} strips with the ‘▪’ shape cross-sections appeared at 300 °C, which was attributed to the different grain growth rates of different Cu{sub 6}Sn{sub 5} crystal faces. - Highlights: • The orientation of interfacial Cu{sub 6}Sn{sub 5} grains was obtained by EBSD technology. • Two types of hollowed Cu{sub 6}Sn{sub 5} strips were found at different temperatures. • The

Phase compatibilities of YBa2Cu3O(9-delta) type structure in quintenary systems Y-Ba-Cu-O-X (impurity)

NASA Technical Reports Server (NTRS)

Karen, P.; Fjellvag, H.; Kjekshus, A.

1990-01-01

Electrical transport properties of the oxidic high T(sub c) superconductors are significantly affected by the presence of minor amounts of various elements adventing as impurities, e.g., from the chemical environment during manufacturing. YBa2Cu3O(9-delta) is prone to an extinction of the superconductivity on (partial) substitution of all four elemental components. E.g., Pr (for Y), La (for Ba), Zn (for Cu) or peroxygroup (for O) substituents will alter some of the superconductivity preconditions, like mixed valence state in Cu3O7/O(9-delta) network or structural distortion of the network. Although various pseudoternary chemical equilibrium phase diagrams of the Y(O)-Ba(O)-Cu(O) system now are available, no consensus is generally shown, however, this is partly due to lack of compatible definitions of the equilibrium conditions. Less information is available about the phase compatibilities in the appropriate quaternary phase diagram (including oxygen) and virtually no information exists about any pentenary phase diagrams (including one impurity). Unfortunately, complexity of such systems, stemming both from number of quaternary or pentenary compounds and from visualizing the five-component phase system, limits this presentation to more or less close surroundings of the YBa2Cu3O(9-delta) type phase in appropriate pseudoquaternary or pseudopseudoternary diagrams, involving Y-Ba-Cu and O, O-CO2, alkaline metals, Mg and alkaline earths, and Sc and most of the 3-d and 4-f elements. The systems were investigated by means of x ray diffraction, neutron diffraction and chemical analytical methods on samples prepared by sol-gel technique from citrates. The superconductivity was characterized by measuring the diamagnetic susceptibility by SQUID.

[The quantitative changes of bioelements (Ca, Zn, Mg, Cu, Mn) in crystalline lenses under the influence of hypodynamic stress and zinc].

PubMed

Kusleika, Saulius

2002-01-01

The aim of the study was to investigate and estimate quantitative changes of bioelements (Ca, Zn, Mg, Cu, Mn) in the lenses on the influence of hypodynamic stress and zinc (Zn). Hypodynamic stress of 48 days duration was provoked for Chinchilla rabbits (n = 20) by placing them in metal hutches. Every day (48 days) 10 rabbits, which had intervention received 0.3 mg/kg body wt. doses of Zn (in form of Zn acetate). The rabbits (n = 10) of the control group, which had no intervention were kept in vivarium conditions. Concentration of bioelements in the lenses of rabbits was detected by atomic absorption spectrophotometry 503 "Perkin-Elmer" (USA). The investigation revealed that hypodynamic stress of 48 days duration caused the increase in amount of Ca, Zn, Mn in lenses as compared with that in control rabbits and in rabbits receiving Zn. The concentration of bioelements (Ca, Zn, Mg, Cu, Mn) in lenses of rabbits receiving Zn in case of hypodynamic stress did not change significantly.

Calculations of stopping powers of 100 eV-30 keV electrons in 31 elemental solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanuma, S.; Powell, C. J.; Penn, D. R.

We present calculated electron stopping powers (SPs) for 31 elemental solids (Li, Be, glassy C, graphite, diamond, Na, Mg, K, Sc, Ti, V, Fe, Y, Zr, Nb, Mo, Ru, Rh, In, Sn, Cs, Gd, Tb, Dy, Hf, Ta, W, Re, Os, Ir, and Bi). These SPs were determined with an algorithm previously used for the calculation of electron inelastic mean free paths and from energy-loss functions (ELFs) derived from experimental optical data. The SP calculations were made for electron energies between 100 eV and 30 keV and supplement our earlier SP calculations for ten additional solids (Al, Si, Cr, Ni,more » Cu, Ge, Pd, Ag, Pt, and Au). Plots of SP versus atomic number for the group of 41 solids show clear trends. Multiple peaks and shoulders are seen that result from the contributions of valence-electron and various inner-shell excitations. Satisfactory agreement was found between the calculated SPs and values from the relativistic Bethe SP equation with recommended values of the mean excitation energy (MEE) for energies above 10 keV. We determined effective MEEs versus maximum excitation energy from the ELFs for each solid. Plots of effective MEE versus atomic number showed the relative contributions of valence-electron and different core-electron excitations to the MEE. For a maximum excitation energy of 30 keV, our effective MEEs agreed well for Be, graphite, Na, Al, and Si with recommended MEEs; a difference for Li was attributed to sample oxidation in the SP measurements for the recommended MEE. Substantially different effective MEEs were found for the three carbon allotropes (graphite, diamond, and glassy C)« less

A comparison study of Co and Cu doped MgO diluted magnetic thin films

NASA Astrophysics Data System (ADS)

Sarıtaş, S.; ćakıcı, T.; Muǧlu, G. Merhan; Kundakcı, M.; Yıldırım, M.

2017-02-01

Transition metal-doped MgO diluted magnetic thin films are appropriate candidates for spintronic applications and designing magnetic devices and sensors. Therefore, MgO:Co and MgO:Cu films were deposited on glass substrates by Chemical Spray Pyrolysis (CSP) method different thin film deposition parameters. Deposited different transition metal doped MgO thin films were compared in terms of optic and structural properties. Comparison optic analysis of the films was investigated spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Comparison structural analysis of the thin films was examined by using XRD, Raman Analysis, SEM, EDX and AFM techniques. The transition metal-doped; MgO:Co and MgO:Cu thin films maybe have potential applications in spintronics and magnetic data storage.

Superconductivity in the Sn-Ba-Sr-Y-Cu-O system

NASA Technical Reports Server (NTRS)

Aleksandrov, K. S.; Khrustalev, B. P.; Krivomazov, S. N.; Petrov, M. I.; Vasilyev, A. D.; Zwegintsev, S. A.

1991-01-01

After the discovery of high-T(sub c) superconductivity in the La-Ba-Cu-O compound, several families of superconducting oxides were synthesized. Here, researchers report the results of the search for superconductivity in the compounds based on tin which has a lone electron pair like Bi, Tl, and Pb. The following compounds were synthesized: Sn1Ba1Sr1Cu3O(sub x), Sn1Ba1Ca1Cu3O(sub x), Sn1Ba1Mg1Cu3O(sub x), Sn1Sr1Ca1Cu3O(sub x), Sn1Sr1Mg1Cu3O(sub x), and Sn1Ca1Mg1Cu3O(sub x). The initial components were oxides and carbonates of the appropriate elements. A standard firing-grinding procedure was used. Final heating was carried out at 960 C during 12 hours. Then the samples were cooled inside the furnace. All the synthesis cycles were carried out in air atmosphere. Among the synthesized compounds only Sn1Ba1Sr1Cu3O(sub x) showed remarkable conductivity. Other compounds were practically dielectrics. Presence of a possible superconductivity in Sn1Ba1Sr1Cu3O(sub x) was defined by using the Meissner effect. At low temperature a deviation from paramagnetic behavior is observed. The hysteresis loops obtained at lower temperature undoubtly testify to the presence of a superconductive phase in the sample. However, the part of the superconductive phase in the Sn1Ba1Sr1Cu3O(sub x) ceramic turned out to be small, less than 2 percent, which agrees with the estimation from magnetic data. In order to increase the content of the superconductive phase, two-valent cations Ba and Sr were partially substituted by univalent (K) and three-valent ones (Y).

Neutron investigation of Nd 2- x- yCe xLa yCuO 4 (0 ⩽ x ⩽ 0.2; y = 0.5, 1)

NASA Astrophysics Data System (ADS)

Gutmann, M.; Allenspach, P.; Fauth, F.; Furrer, A.; Zolliker, M.; Rosenkranz, S.; Eccleston, R. S.

1997-02-01

We present neutron diffraction and crystal field (CF) spectroscopy results obtained for the electron-doped superconductor precursor material Nd 2- x- yCe xLa yCuO 4 (0 ⩽ x ⩽ 0.2; y = 0.5, 1). Samples were prepared via a sol-gel methods. The lattice constants as a function of Ce-doping show the well-known behavior common to this class of compounds, i.e. the a parameter increases while the c parameter decreases with increasing Ce amount. The presence of La expands the unit cell in all directions compared to the mother compound Nd 2CuO 4 while preserving the T‧-structure for the above mentioned range. The CF spectra clearly show the presence of electronic inhomogeneities associated with electron doping from Ce 4+ on one Cu-site in the CuO 2-planes.

Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects

NASA Astrophysics Data System (ADS)

Hsu, Kuo-Chung; Perng, Dung-Ching; Yeh, Jia-Bin; Wang, Yi-Chun

2012-07-01

A 5 nm thick Cr added Ru film has been extensively investigated as a seedless Cu diffusion barrier. High-resolution transmission electron microscopy micrograph, X-ray diffraction (XRD) pattern and Fourier transform-electron diffraction pattern reveal that a Cr contained Ru (RuCr) film has a glassy microstructure and is an amorphous-like film. XRD patterns and sheet resistance data show that the RuCr film is stable up to 650 °C, which is approximately a 200 °C improvement in thermal stability as compared to that of the pure Ru film. X-ray photoelectron spectroscopy depth profiles show that the RuCr film can successfully block Cu diffusion, even after a 30-min 650 °C annealing. The leakage current of the Cu/5 nm RuCr/porous SiOCH/Si stacked structure is about two orders of magnitude lower than that of a pristine Ru sample for electric field below 1 MV/cm. The RuCr film can be a promising Cu diffusion barrier for advanced Cu metallization.

41 CFR 60-30.36 - Exceptions to recommendations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... recommendations. 60-30.36 Section 60-30.36 Public Contracts and Property Management Other Provisions Relating to... EXECUTIVE ORDER 11246 Expedited Hearing Procedures § 60-30.36 Exceptions to recommendations. Within 10 days... said recommendations. Exceptions may be responded to by other parties within 7 days after receipt by...

41 CFR 60-30.36 - Exceptions to recommendations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... recommendations. 60-30.36 Section 60-30.36 Public Contracts and Property Management Other Provisions Relating to... EXECUTIVE ORDER 11246 Expedited Hearing Procedures § 60-30.36 Exceptions to recommendations. Within 10 days... said recommendations. Exceptions may be responded to by other parties within 7 days after receipt by...

The local environment of Cu+ in Cu-Y zeolite and its relationship to the synthesis of dimethyl carbonate.

PubMed

Drake, Ian J; Zhang, Yihua; Briggs, Daniel; Lim, Bomyi; Chau, Tanguy; Bell, Alexis T

2006-06-22

Cu-exchanged Y zeolite was investigated in order to determine the location of the copper cations relative to the zeolite framework and to determine which Cu cations are active for the oxidative carbonylation of methanol to dimethyl carbonate (DMC). Cu-Y zeolite was prepared by vapor-phase exchange of H-Y with CuCl. The oxidation state, local coordination, and bond distances of Al and Cu were determined using Al K-edge and Cu K-edge X-ray absorption spectroscopy (XAS). Complimentary information was obtained by H2 temperature-programmed reduction and by in-situ infrared spectroscopy. Cu-Y has a Cu/Al ratio of unity and very little occluded CuCl. The average Al-O and Al-Cu bond distances are 1.67 angstroms and 2.79 angstroms, respectively, and the average Cu-O and Cu-Si(Al) bond distances are 1.99 angstroms and 3.13 angstroms, respectively. All of the Cu exchanged is present as Cu+ in sites I', II, and III'. Cu-Y is active for the oxidative carbonylation of methanol, and at low reactant contact time produces DMC as the primary product. With increasing reactant contact time, DMC formation decreases in preference to the formation of dimethoxy methane (DMM) and methylformate (MF). The formation of DMM and MF is attributed to the hydrogenation of DMC and the hydrogenolysis of DMM, respectively. Observation of the catalyst under reaction conditions reveals that most of the copper cations remain as Cu+, but some oxidation of Cu+ to Cu2+ does occur. It is also concluded that only those copper cations present in site II and III' positions are accessible to the reactants, and hence are catalytically active. The dominant adsorbed species on the surface are methoxy groups, and adsorbed CO is present as a minority species. The relationship of these observations to the kinetics of DMC synthesis is discussed.

Enhancement of spin-Seebeck effect by inserting ultra-thin Fe{sub 70}Cu{sub 30} interlayer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kikuchi, D., E-mail: d.kikuchi@imr.tohoku.ac.jp; WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577; Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577

2015-02-23

We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe{sub 70}Cu{sub 30}/BiY{sub 2}Fe{sub 5}O{sub 12} (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe{sub 70}Cu{sub 30} interlayer. This enhancement decays sharply with increasing the Fe{sub 70}Cu{sub 30} thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe{sub 70}Cu{sub 30} interlayer. Combined with control experiments using Pt/Fe{sub 70}Cu{sub 30} devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe{sub 70}Cu{sub 30}/BiYIG devices is attributedmore » to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.« less

Influence of Cu Content on the Microstructure and Mechanical Properties of Cr-Cu-N Coatings

PubMed Central

Ding, Ji Cheng; Zhang, Teng Fei; Wan, Zhi Xin; Mei, Hai Juan; Kang, Myung Chang

2018-01-01

The Cr-Cu-N coatings with various Cu contents (0–25.18 (±0.17) at.%) were deposited on Si wafer and stainless steel (SUS 304) substrates in reactive Ar+N2 gas mixture by a hybrid coating system combining pulsed DC and RF magnetron sputtering techniques. The influence of Cu content on the coating composition, microstructure, and mechanical properties was investigated. The microstructure of the coatings was significantly altered by the introduction of Cu. The deposited coatings exhibit solid solution structure with different compositions in all of the samples. Addition of Cu is intensively favored for preferred orientation growth along (200) direction by restricting in (111) direction. With increasing Cu content, the surface and cross-sectional morphology of coatings were changed from triangle cone-shaped, columnar feature to broccoli-like and compact glassy microstructure, respectively. The mechanical properties including the residual stress, nanohardness, and toughness of the coatings were explored on the basis of Cu content. The highest hardness was obtained at the Cu content of 1.49 (±0.10) at.%. PMID:29552269

Influence of Cu Content on the Microstructure and Mechanical Properties of Cr-Cu-N Coatings.

PubMed

Ding, Ji Cheng; Zhang, Teng Fei; Wan, Zhi Xin; Mei, Hai Juan; Kang, Myung Chang; Wang, Qi Min; Kim, Kwang Ho

2018-01-01

The Cr-Cu-N coatings with various Cu contents (0-25.18 (±0.17) at.%) were deposited on Si wafer and stainless steel (SUS 304) substrates in reactive Ar+N 2 gas mixture by a hybrid coating system combining pulsed DC and RF magnetron sputtering techniques. The influence of Cu content on the coating composition, microstructure, and mechanical properties was investigated. The microstructure of the coatings was significantly altered by the introduction of Cu. The deposited coatings exhibit solid solution structure with different compositions in all of the samples. Addition of Cu is intensively favored for preferred orientation growth along (200) direction by restricting in (111) direction. With increasing Cu content, the surface and cross-sectional morphology of coatings were changed from triangle cone-shaped, columnar feature to broccoli-like and compact glassy microstructure, respectively. The mechanical properties including the residual stress, nanohardness, and toughness of the coatings were explored on the basis of Cu content. The highest hardness was obtained at the Cu content of 1.49 (±0.10) at.%.

Transient and modulated charge separation at CuInSe2/C60 and CuInSe2/ZnPc hybrid interfaces

NASA Astrophysics Data System (ADS)

von Morzé, Natascha; Dittrich, Thomas; Calvet, Wolfram; Lauermann, Iver; Rusu, Marin

2017-02-01

Spectral dependent charge transfer and exciton dissociation have been investigated at hybrid interfaces between inorganic polycrystalline CuInSe2 (untreated and Na-conditioned) thin films and organic C60 as well as zinc phthalocyanine (ZnPc) layers by transient and modulated surface photovoltage measurements. The stoichiometry and electronic properties of the bare CuInSe2 surface were characterized by photoelectron spectroscopy which revealed a Cu-poor phase with n-type features. After the deposition of the C60 layer, a strong band bending at the CuInSe2 surface was observed. Evidence for dissociation of excitons followed by charge separation was found at the CuInSe2/ZnPc interface. The Cu-poor layer at the CuInSe2 surface was found to be crucial for transient and modulated charge separation at CuInSe2/organic hybrid interfaces.

Structural investigation of Y1-xNixBa2Cu3O7-δ superconductor

NASA Astrophysics Data System (ADS)

Hadi-Sichani, Behnaz; Shakeripour, Hamideh; Salamati, Hadi

2018-07-01

Y1-xNixBa2Cu3O7-δ superconducting samples with 0 ≤ x ≤ 0.02 were synthesized by standard solid-state reaction and characterized by the X-ray powder diffraction technique. The Rietveld fitted XRD refinements show that all samples are crystallized in single phase, having orthorhombic structure with Pmmm space group. We investigated the effect of adding a magnetic element on the structure of this superconductor. The c cell parameter increases by doping of Ni until to an optimal value of Ni content, x ∼ 0.004, and then starts to decrease by higher value of Ni substitution. Moreover, it is seen that Cu(2)sbnd O(2) bond length decreases with increasing Ni up to the optimal concentration of Ni, too. The CuO2 planes become more distorted and hence charge carriers may have better chances of transportation to the CuO2 planes. By further increasing of Ni content than the optimal value, the Cu(2)sbnd O(2) bond lengths start to increase, and cause CuO2 planes to be flatten. We suggest, besides affecting the magnetic characteristic of Ni impurity, the Ni substitution leads to interesting crystallographic changes.

In vitro degradation of MAO/PLA coating on Mg-1.21Li-1.12Ca-1.0Y alloy

NASA Astrophysics Data System (ADS)

Zeng, Rong-Chang; Qi, Wei-Chen; Song, Ying-Wei; He, Qin-Kun; Cui, Hong-Zhi; Han, En-Hou

2014-12-01

Magnesium and its alloys are promising biomaterials due to their biocompatibility and osteoinduction. The plasticity and corrosion resistance of commercial magnesium alloys cannot meet the requirements for degradable biomaterials completely at present. Particularly, the alkalinity in the microenvironment surrounding the implants, resulting from the degradation, arouses a major concern. Micro-arc oxidation (MAO) and poly(lactic acid) (PLA) composite (MAO/PLA) coating on biomedical Mg-1.21Li-1.12Ca-1.0Y alloy was prepared to manipulate the pH variation in an appropriate range. Surface morphologies were discerned using SEM and EMPA. And corrosion resistance was evaluated via electrochemical polarization and impedance and hydrogen volumetric method. The results demonstrated that the MAO coating predominantly consisted of MgO, Mg2SiO4 and Y2O3. The composite coating markedly improved the corrosion resistance of the alloy. The rise in solution pH for the MAO/PLA coating was tailored to a favorable range of 7.5-7.8. The neutralization caused by the alkalinity of MAO and Mg substrate and acidification of PLA was probed. The result designates that MAO/PLA composite coating on Mg-1.21Li-1.12Ca-1.0Y alloys may be a promising biomedical coating.

Effect of Nb Content on Mechanical Behavior and Structural Properties of W/(Zr55Cu30Al10Ni5)100- x Nb x Composite

NASA Astrophysics Data System (ADS)

Mahmoodan, Morteza; Gholamipour, Reza; Mirdamadi, Shamseddin; Nategh, Said

2017-05-01

In the present study, (Zr55Cu30Al10Ni5)100- x Nb( x=0,1,2,3) bulk metallic glass matrix/tungsten wire composites were fabricated by infiltration process. Structural studies were investigated by scanning electron microscopy and X-ray diffraction method. Also, mechanical behaviors of the materials were analyzed using quasi-static compressive tests. Results indicated that the best mechanical properties i.e., 2105 MPa compressive ultimate strength and 28 pct plastic strain before failure, were achieved in the composite sample with X = 2. It was also found that adding Nb to the matrix modified interface structure in W fiber/(Zr55Cu30Al10Ni5)98Nb2 since the stable diffusion band formation acts as a functionally graded layer. Finally, the observation of multiple shear bands formation in the matrix could confirm the excellent plastic deformation behavior of the composite.

Simplified and reproducible radiochemical separations for the production of high specific activity 61Cu, 64Cu, 86Y and 55Co

NASA Astrophysics Data System (ADS)

Valdovinos, Hector F.; Graves, Stephen; Barnhart, Todd; Nickles, Robert J.

2017-05-01

Four positron-emitting radiometals 61Cu, 64Cu, 86Y and 55Co are increasingly being employed as labels for positron emission tomography (PET) imaging due to their favorable half-lives that match the pharmacokinetics of targeting moeities such as peptides, antibodies and antibody fragments and due to their use in internal dosimetry and treatment planning of targeted radionuclide therapy when they are substituted by their therapeutic analogues 67Cu, 90Y and 58mCo. The main disadvantage of the production methods reported in the literature for these radionuclides is that the final separated radioactive product is diluted in a large volume (> 5 mL), which obligates a lengthy evaporation step in a large vessel that is difficult to automate in-line after the chromatographic steps and that results in a highly variable amount of radioactivity lost in the vessel's surface. In this work we present simplified radiochemical separation methods for the production of 61Cu, 64Cu, 86Y and 55Co that result in: 1) a final eluate volume ≤ 600 µL; 2) reproducible separation yields of 84±4%, 82±6%, 94±5% and 93±6%, respectively; and 3) effective specific activities of 64.0±45.0 GBq/μmol NOTA, 114.9±40.1 GBq/μmol NOTA, 1.4±0.5 GBq/μmol DTPA and 10.1±5.7 GBq/μmol NOTA, respectively; without compromising the recycling efficiencies of the respective isotopically-enriched target materials 60Ni, 64Ni, 86SrCO3 and 58Ni, which accounted for 98±1%, 96±3%, 90±3% and 94±1%, respectively.

Characterization of Al-Cu-Mg-Ag Alloy RX226-T8 Plate

NASA Technical Reports Server (NTRS)

Lach, Cynthia L.; Domack, Marcia S.

2003-01-01

aircraft wing and fuselage skin materials through the addition of silver to Al-Cu-Mg alloys based on Al 2519 chemistry [2]. Thermal stability of the resulting Al-Cu-Mg-Ag alloys, C415-T8 and C416-T8, was due to co-precipitation of the thermally stable . (AlCu) and ' (Al2Cu) strengthening phases [1-4]. The strength and toughness behavior was investigated for these alloys produced as 0.090-inch thick rolled sheet in the T8 condition and after various thermal exposures. The mechanical properties were shown to be competitive with conventional aircraft alloys, 2519-T8 and 2618-T8 [2]. During the Integral Airframe Structure (IAS) program, advanced aluminum alloys were examined for use in an integrally stiffened airframe structure where the skin and stiffeners would be machined from plate and extruded frames would be mechanically attached (see Figure 1) [5]. Advantages of integrally stiffened structure include reduced part count, and reduced assembly times compared to conventional built-up airframe structure. The near-surface properties of a thick plate are of significance for a machined integrally stiffened airframe structure since this represents the skin location. Properties measured at the mid-plane of the plate are more representative of the stiffener web. RX226 was developed to exploit strength-toughness improvements and thermal stability benefits of Al-Cu-Mg-Ag alloys in plate gages. This study evaluated the microstructure and properties of three gages of plate produced in the T8 condition.

TPD IR studies of CO desorption from zeolites CuY and CuX

NASA Astrophysics Data System (ADS)

Datka, Jerzy; Kozyra, Paweł

2005-06-01

The desorption of CO from zeolites CuY and CuX was followed by TPD-IR method. This is a combination of temperature programmed desorption and IR spectroscopy. In this method, the status of activated zeolite (before adsorption), the process of adsorption, and the status of adsorbed molecules can be followed by IR spectroscopy, and the process of desorption (with linear temperature increase) can be followed both by IR spectroscopy and by mass spectrometry. IR spectra have shown two kinds of Cu + sites in both CuY and CuX. Low frequency (l.f.) band (2140 cm -1 in CuY and 2130 cm -1 in CuX) of adsorbed CO represents Cu + sites for which π back donation is stronger and σ donation is weaker whereas high frequency h.f. band (2160 cm -1 in CuY and 2155 cm -1 in CuX) represent Cu + sites for which π back donation is weaker and σ donation is stronger. The TPD-IR experiments evidenced that the Cu + sites represented by l.f. band bond CO more weakly than those represented by h.f. one, indicating that σ donation has more important impact to the strength of Cu +-CO bonding. On the contrary, π back donation has bigger contribution to the activation of adsorbed molecules.

Study of optical properties of vacuum evaporated carbon nanotube containing Se80Te16Cu4 thin films

NASA Astrophysics Data System (ADS)

Upadhyay, A. N.; Tiwari, R. S.; Singh, Kedar

2016-08-01

Thin films of Se80Te16Cu4 glassy alloy and 3 wt.% of carbon nanotubes (CNTs) containing Se80Te16Cu4 glassy composite were deposited on clean glass substrate by thermal evaporation technique. The scanning electron microscope and energy dispersive x-ray analysis were performed to investigate the surface morphology and elemental composition of as synthesised samples. The reflectance and transmittance spectra of as-deposited thin films were recorded (200-1100 nm) by using UV/VIS/NIR spectrophotometer. The optical band gap and optical constants such as absorption coefficient (α), refractive index (n) and extinction coefficient (k) of Se80Te16Cu4 and 3 wt.% CNTs-Se80Te16Cu4 glassy composite thin films were calculated. It is observed that optical properties alter due to CNTs incorporation in Se80Te16Cu4 glassy alloy. Effect on optical properties due to CNTs incorporation can be explained in terms of concentration of unsaturated bonds/defects in the localised states.

Investigation of irradiated rats DNA in the presence of Cu(II) chelates of amino acids Schiff bases.

PubMed

Karapetyan, N H; Torosyan, A L; Malakyan, M; Bajinyan, S A; Haroutiunian, S G

2016-01-01

The new synthesized Cu(II) chelates of amino acids Schiff bases were studied as a potential radioprotectors. Male albino rats of Wistar strain were exposed to X-ray whole-body irradiation at 4.8 Gy. This dose caused 30% mortality of the animals (LD30). The survival of animals exposed to radiation after preliminary administration of 10 mg/kg Cu(II)(Nicotinyl-L-Tyrosinate)2 or Cu(II)(Nicotinyl-L-Tryptophanate)2 prior to irradiation was registered about 80 and 100% correspondingly. Using spectrophotometric melting and agarose gel electrophoresis methods, the differences between the DNA isolated from irradiated rats and rats pretreated with Cu(II) chelates were studied. The fragments of DNA with different breaks were revealed in DNA samples isolated from irradiated animals. While, the repair of the DNA structure was observed for animals pretreated with the Cu(II) chelates. The results suggested that pretreatment of the irradiated rats with Cu(II)(Nicotinyl-L-Tyrosinate)2 and Cu(II)(Nicotinyl-L-Tryptophanate)2 compounds improves the liver DNA characteristics.

Cooling rate dependence of simulated Cu{sub 64.5}Zr{sub 35.5} metallic glass structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryltsev, R. E.; Ural Federal University, 19 Mira Str., 620002 Ekaterinburg; L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow

Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu{sub 64.5}Zr{sub 35.5} alloy during the cooling in a wide range of cooling rates γ ∈ (1.5 ⋅ 10{sup 9}, 10{sup 13}) K/s. Investigating short- and medium-range orders, we show that the structure of Cu{sub 64.5}Zr{sub 35.5} metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to an increase of abundances of both the icosahedral-like clusters and Frank-Kasper Z16 polyhedra. The amounts of these clusters in the glassy state drastically increase at the γ{sub min} = 1.5 ⋅ 10{supmore » 9} K/s. Analysing the structure of the glass at γ{sub min}, we observe the formation of nano-sized crystalline grain of Cu{sub 2}Zr intermetallic compound with the structure of Cu{sub 2}Mg Laves phase. The structure of this compound is isomorphous with that for Cu{sub 5}Zr intermetallic compound. Both crystal lattices consist of two types of clusters: Cu-centered 13-atom icosahedral-like cluster and Zr-centered 17-atom Frank-Kasper polyhedron Z16. That suggests the same structural motifs for the metallic glass and intermetallic compounds of Cu–Zr system and explains the drastic increase of the abundances of these clusters observed at γ{sub min}.« less

Controlling superstructural ordering in the clathrate-I Ba 8 M 16 P 30 (M = Cu, Zn) through the formation of metal–metal bonds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolyniuk, J.; Whitfield, P. S.; Lee, K.

2017-01-01

Order–disorder–order phase transitions in the clathrate-I Ba8Cu16P30 were induced and controlled by aliovalent substitutions of Zn into the framework. Unaltered Ba8Cu16P30 crystallizes in an ordered orthorhombic (Pbcn) clathrate-I superstructure that maintains complete segregation of metal and phosphorus atoms over 23 different crystallographic positions in the clathrate framework. The driving force for the formation of this Pbcn superstructure is the avoidance of Cu–Cu bonds. This superstructure is preserved upon aliovalent substitution of Zn for Cu in Ba8Cu16-xZnxP30 with 0 < x < 1.6 (10% Zn/Mtotal), but vanishes at greater substitution concentrations. Higher Zn concentrations (up to 35% Zn/Mtotal) resulted in themore » additional substitution of Zn for P in Ba8M16+yP30-y (M = Cu, Zn) with 0 ≤ y ≤ 1. This causes the formation of Cu–Zn bonds in the framework, leading to a collapse of the orthorhombic superstructure into the more common cubic subcell of clathrate-I (Pm[3 with combining macron]n). In the resulting cubic phases, each clathrate framework position is jointly occupied by three different elements: Cu, Zn, and P. Detailed structural characterization of the Ba–Cu–Zn–P clathrates-I via single crystal X-ray diffraction, joint synchrotron X-ray and neutron powder diffractions, pair distribution function analysis, electron diffraction and high-resolution electron microscopy, along with elemental analysis, indicates that local ordering is present in the cubic clathrate framework, suggesting the evolution of Cu–Zn bonds. For the compounds with the highest Zn content, a disorder–order transformation is detected due to the formation of another superstructure with trigonal symmetry and Cu–Zn bonds in the clathrate-I framework. It is shown that small changes in the composition, synthesis, and crystal structure have significant impacts on the structural and transport properties of Zn-substituted Ba8Cu16P30.« less

(abstract) Undercooling Studies of the Bulk Metallic Glass Forming Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) Alloy During Containerless Electrostatic Levitation Processing

NASA Technical Reports Server (NTRS)

Kim, Y. J.; Busch, R.; Johnson, W. L.; Rulison, A. J.; Rhim, W. K.

1995-01-01

Bulk glass forming metallic alloys have long been desired for technological applications and for investigation into liquid undercooling, solidification processes, and thermophysical properties. A glass forming alloy Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) was used to investigate the thermal treatments affecting undercooling and vitrification. The experiments were performed using the high temperature high vacuum electrostatic levitator at JPL. A sample approximately 3 mm in diameter was melted, superheated, undercooled, and solidified while levitated in high vacuum. The results show that when the sample was held above its melting temperature for a sufficient period of time to dissolve oxides and then cooled faster than a critical cooling rate, it undercooled to the glass transition temperature, T(sub g), and formed a glassy alloy. The required critical cooling rate for metallic glass formation was obtained to be between 0.9 K per second and 1.2 K per second for the 42.4 mg sample.

Comparison of the effects of esomeprazole 40 mg, rabeprazole 20 mg, lansoprazole 30 mg, and pantoprazole 40 mg on intragastrıc pH in extensive metabolizer patients with gastroesophageal reflux disease.

PubMed

Çelebi, Altay; Aydın, Dinçer; Kocaman, Orhan; Konduk, Buğra Tolga; Şentürk, Ömer; Hülagü, Sadetin

2016-09-01

Studies on the therapeutic efficacy of proton pump inhibitors (PPIs) in patients with gastroesophageal reflux disease (GERD) have been recently published. In most of these studies, comparison of only two PPIs have been made. There are few studies on the comparison of four or more PPIs. We aimed to compare the acid inhibitory effects of esomeprazole 40 mg, rabeprazole 20 mg, lansoprazole 30 mg, and pantoprazole 40 mg on days 1 and 5 of treatment in patients with GERD, who were extensive metabolizers in regard to the CYP2C19 genotype. Helicobacter pylori-negative with typical symptoms of GERD patients were randomly divided into four treatment groups. Efficacy analysis on days 1 and 5 were performed on the four groups which comprised 10 (esomeprazole), 11 (rabeprazole), 10 (lansoprazole), and 10 (pantoprazole) patients. On day 1 of PPI treatment, the mean percentage of time with intragastric Ph>4 were 54%, 58%, 60%, and 35% for the groups, respectively, and on day 5, these values were 67%, 60%, 68%, and 59%, respectively. Esomeprazole, rabeprazole, and lansoprazole were found to be superior to pantoprazole on the first day of treatment. Pantoprazole is a less potent proton pump inhibitor than the other PPIs tested on the first day of treatment. When the time needed to raise the intragatric pH to over 4 was evaluated, esomeprazole was found to have the most rapid action, followed by lansoprazole and rabeprazole.

SALT long-slit spectroscopy of CTS C30.10: two-component Mg II line

NASA Astrophysics Data System (ADS)

Modzelewska, J.; Czerny, B.; Hryniewicz, K.; Bilicki, M.; Krupa, M.; Świȩtoń, A.; Pych, W.; Udalski, A.; Adhikari, T. P.; Petrogalli, F.

2014-10-01

Context. Quasars can be used as a complementary tool to SN Ia to probe the distribution of dark energy in the Universe by measuring the time delay of the emission line with respect to the continuum. The understanding of the Mg II emission line structure is important for cosmological application and for the black hole mass measurements of intermediate redshift quasars. Aims: Knowing the shape of Mg II line and its variability allows for identifying which part of the line should be used to measure the time delay and the black hole mass. We thus aim at determining the structure and the variability of the Mg II line, as well as the underlying Fe II pseudo-continuum. Methods: We performed five spectroscopic observations of a quasar CTS C30.10 (z = 0.9000) with the SALT telescope between December 2012 and March 2014, and we studied the variations in the spectral shape in the 2700 Å-2900 Å rest frame. Results: We show that the Mg II line in this source consists of two kinematic components, which makes the source representative of type B quasars. Both components were modeled well with a Lorentzian shape, and they vary in a similar way. The Fe II contribution seems to be related only to the first (blue) Mg II component. Broad band spectral fitting instead favor the use of the whole line profile. The contribution of the narrow line region to Mg II is very low, below 2%. The Mg II variability is lower than the variability of the continuum, which is consistent with the simple reprocessing scenario. The variability level of CTS C30.10 and the measurement accuracy of the line and continuum is high enough to expect that further monitoring will allow the time delay between the Mg II line and continuum to be measured. Based on observations made with the Southern African Large Telescope (SALT) under program 2012-2-POL-003 and 2013-1-POL-RSA-002 (PI: B. Czerny).Spectra shown in Figs. 3 and 4 are only available in electronic form at the CDS via anonymous ftp to http

Liraglutide 3.0 mg for Weight Management: A Population Pharmacokinetic Analysis.

PubMed

Overgaard, Rune V; Petri, Kristin C; Jacobsen, Lisbeth V; Jensen, Christine B

2016-11-01

This analysis used a population pharmacokinetic approach to identify covariates that influence plasma exposure of liraglutide 3.0 mg, a glucagon-like peptide-1 (GLP-1) receptor agonist approved for weight management in overweight and obese individuals. Samples for pharmacokinetic analysis were drawn at weeks 2, 12 and 28 of the phase IIIa SCALE Obesity and Prediabetes (N = 2339) and SCALE Diabetes (N = 584) trials. Dose proportionality of liraglutide in obese subjects was investigated using data from a phase II dose-finding study (N = 331). Dose-proportional exposure of liraglutide up to and including 3.0 mg was confirmed. Body weight and sex influenced exposure of liraglutide 3.0 mg, while age ≥70 years, race, ethnicity and baseline glycaemic status did not. Compared with a reference subject weighing 100 kg, exposure of liraglutide 3.0 mg was 44 % lower for a subject weighing 234 kg (90 % CI 41-47), 41 % higher for a subject weighing 60 kg (90 % CI 37-46), and 32 % higher (90 % CI 28-35) in females than males with the same body weight. Neither injection site nor renal function significantly influenced exposure of liraglutide 3.0 mg (post hoc analysis). Population pharmacokinetics of liraglutide up to and including 3.0 mg daily in overweight and obese adults demonstrated dose-proportional exposure, and limited effect of covariates other than sex and body weight. These findings were similar to those previously observed with liraglutide up to 1.8 mg in subjects with type 2 diabetes mellitus. Further analysis of exposure-response relationship and its effect on dose requirements is addressed in a separate publication.

Thermophysical properties of Cu-In-Sn liquid Pb-free alloys: viscosity and surface tension

NASA Astrophysics Data System (ADS)

Dogan, Ali; Arslan, Hüseyin

2018-01-01

The viscosity of a few Cu-In-Sn liquid alloys has been investigated by a number of geometric (Muggianu, Kohler, Toop) and physical thermodynamic models (Kozlov-Romanov-Petrov, Budai-Benko-Kaptay, Schick et al.) and GSM for the cross section (z/y = 1/3) in Pb-free liquid alloy Cux-Iny-Snz at 1073 K. Moreover, the surface tensions of the same liquid alloys have been investigated by a number of geometric models and the Butler model for the cross section Cux-Iny-Snz (z/(y + z) = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) at the same temperature. The best agreement of the surface tensions was obtained in the Kohler model for xCu = 10 at % and the Butler model for xCu = 20 at % and xCu = 30 at.%, respectively. The best agreement among chosen geometric and physical models and experiment for these selected sections Cu80In15Sn5, Cu75In15Sn10, Cu55In7Sn38, Cu33In50Sn17 and Cu26In55Sn19 at 1073 K was obtained for the Budai-Benkö-Kaptay model.

Analysis of Relations Between the Level of Mg, Zn, Ca, Cu, and Fe and Depressiveness in Postmenopausal Women.

PubMed

Szkup, Małgorzata; Jurczak, Anna; Brodowska, Aleksandra; Brodowska, Agnieszka; Noceń, Iwona; Chlubek, Dariusz; Laszczyńska, Maria; Karakiewicz, Beata; Grochans, Elżbieta

2017-03-01

Numerous observations suggest a possible connection between the levels of Mg, Zn, Fe, and Zn and the incidence of depressive symptoms. Depression is two to three times more common in women than in men. The menopausal period is extremely conducive to depressive disorders. The aim of this study was to assess the severity of depressive symptoms in postmenopausal women depending on the levels of Mg, Zn, Ca, Cu, and Fe. The study included 198 healthy postmenopausal women at the average age of 56.26 ± 5.55 years. In the first part of the study, standardized research tools were used, namely the Primary Care Evaluation of Mental Disorders (PRIME-MD) and the Beck Depression Inventory (BDI). The second part involved biochemical analysis of Mg, Zn, Ca, Cu, and Fe levels in blood serum. The lowest Cu levels were observed in women without depressive symptoms (1.07 ± 0.22 mg/l) and the highest in those with severe depressive symptoms (1.19 ± 0.17 mg/l), (p ≤ 0.05). The lowest Mg levels were observed in women with depressive symptoms (14.28 ± 2.13 mg/l), and the highest in women without depressive symptoms (16.30 ± 3.51 mg/l), (p ≤ 0.05). The average serum Mg levels (15.75 ± 3.23 mg/l) decreased compared to the reference values (18.77-24 mg/l). What is striking is a potential relation between the levels of Mg and Cu and depressiveness. Our results indicate to a higher vulnerability to depression in a group of women with lower levels of Mg and higher levels of Cu.

Magnetic properties of quadruple perovskite solid solutions Ca{sub 1–x}Y{sub x}Cu{sub 3}Fe{sub 4}O{sub 12} and Y{sub 1–y}Ce{sub x}Cu{sub 3}Fe{sub 4}O{sub 12}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murakami, Makoto; Mori, Shigeo; Yamada, Ikuya, E-mail: i-yamada@21c.osakafu-u.ac.jp

Magnetic properties of the quadruple perovskite solid solutions Ca{sub 1–x}Y{sub x}Cu{sub 3}Fe{sub 4}O{sub 12} and Y{sub 1–y}Ce{sub y}Cu{sub 3}Fe{sub 4}O{sub 12} are investigated. Ca{sub 1–x}Y{sub x}Cu{sub 3}Fe{sub 4}O{sub 12} shows continuous increase in the ferromagnetic transition temperature as x increases. Y{sub 1–y}Ce{sub y}Cu{sub 3}Fe{sub 4}O{sub 12} exhibits a ferromagnetic-antiferromagnetic transition in the vicinity of y = 0.5. These observations demonstrate the electron doping effect on magnetic properties of charge-disproportionated ACu{sub 3}Fe{sub 4}O{sub 12} phases.

Bioleaching characteristics, influencing factors of Cu solubilization and survival of Herbaspirillum sp. GW103 in Cu contaminated mine soil.

PubMed

Govarthanan, Muthusamy; Lee, Gun-Woong; Park, Jung-Hee; Kim, Jae Su; Lim, Sung-Sik; Seo, Sang-Ki; Cho, Min; Myung, Hyun; Kamala-Kannan, Seralathan; Oh, Byung-Taek

2014-08-01

This study was aimed at assess the potential of diazotrophic bacteria, Herbaspirillum sp. GW103, for bioleaching of Cu in mine soil. The strain exhibited resistance to As (550mgL(-1)), Cu (350mgL(-1)), Zn (300mgL(-1)) and Pb (200mgL(-1)). The copper resistance was further confirmed by locating copA and copB genes. The survival of the isolate GW103 during bioleaching was analyzed using green fluorescent protein tagged GW103. Response surface methodology based Box-Behnken design was used to optimize the physical and chemical conditions for Cu bioleaching. Five significant variables (temperature, incubation time, CaCO3, coconut oil cake (COC), agitation rate) were selected for the optimization. Second-order polynomials were established to identify the relationship between Cu bioleaching and variables. The optimal conditions for maximum Cu bioleaching (66%) were 30°C, 60h of incubation with 1.75% of CaCO3 and 3% COC at 140rpm. The results of Cu sequential extraction studies indicated that the isolate GW103 leached Cu from ion-exchangeable, reducible, strong organic and residual fractions. Obtained results point out that the isolate GW103 could be used for bioleaching of Cu from mine soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cu6Sn5 Whiskers Precipitated in Sn3.0Ag0.5Cu/Cu Interconnection in Concentrator Silicon Solar Cells Solder Layer

PubMed Central

Zhang, Liang; Liu, Zhi-quan; Yang, Fan; Zhong, Su-juan

2017-01-01

Cu6Sn5 whiskers precipitated in Sn3.0Ag0.5Cu/Cu interconnection in concentrator silicon solar cells solder layer were found and investigated after reflow soldering and during aging. Ag3Sn fibers can be observed around Cu6Sn5 whiskers in the matrix microstructure, which can play an active effect on the reliability of interconnection. Different morphologies of Cu6Sn5 whiskers can be observed, and hexagonal rod structure is the main morphology of Cu6Sn5 whiskers. A hollow structure can be observed in hexagonal Cu6Sn5 whiskers, and a screw dislocation mechanism was used to represent the Cu6Sn5 growth. Based on mechanical property testing and finite element simulation, Cu6Sn5 whiskers were regarded as having a negative effect on the durability of Sn3.0Ag0.5Cu/Cu interconnection in concentrator silicon solar cells solder layer. PMID:28772686

Effects of minor Cu and Si additions on glass forming ability and mechanical properties of Co-Fe-Ta-B Bulk metallic glass

NASA Astrophysics Data System (ADS)

Yazici, Ziya Ozgur; Hitit, Aytekin; Yalcin, Yilmaz; Ozgul, Metin

2016-01-01

Effect of Cu and Si substitutions for Co and B on the glass forming ability (GFA) of Co(43-x)CuxFe20Ta5.5B(31.5-x)Siy (x=0-1.5 and y=5-10) were systematically investigated by X-ray diffraction, optical microscopy, scanning electron microscopy, and differential scanning calorimetry. In order to evaluate the contribution of copper and silicon, appropriate amounts of copper and silicon were individually introduced to the base alloy composition. By using the effects of copper and silicon together, significant enhancement was obtained and the critical casting thickness (CCT) of the base alloy was increased three times from 2 mm to 6 mm. Moreover, mechanical properties of the alloys were examined by compression tests and Vickers hardness measurements. The compression test results revealed that the glassy alloys having enhanced GFA shows high strength of about 3500-4000 MPa. In addition, existence of (Co,Fe)2B and (Co,Fe)20.82Ta2.18B6 crystalline phases in glassy matrix influences the hardnesses of the alloys compared to monolitic glassy structure having hardness of about 1200 Hv.

Kinetics of Glass Transition and Crystallization of a Zr40Hf10Ti4Y1Al10Cu25Ni7Co2Fe1 Bulk Metallic Glass with High Mixing Entropy

NASA Astrophysics Data System (ADS)

Gong, Pan; Wang, Sibo; Li, Fangwei; Wang, Xinyun

2018-04-01

The kinetics of glass transition and crystallization of a novel Zr40Hf10Ti4Y1Al10Cu25Ni7Co2Fe1 bulk metallic glass (BMG) with high mixing entropy have been studied by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The continuous DSC curves show five stages of crystallization at lower heating rates (≤ 20 K/min). The activation energies of glass transition were determined by Moynihan and Kissinger methods, while the activation energies of crystallization were calculated utilizing Kissinger, Ozawa, and Boswell models. The crystalline phases corresponding to each crystallization step have been found out. The kinetic fragility of Zr40Hf10Ti4Y1Al10Cu25Ni7Co2Fe1 BMG has also been evaluated. Based on the isothermal DSC curves, the Avrami exponent, evaluated from the Johnson-Mehl-Avrami equation, has been analyzed in detail. The current study reveals that the crystallization behavior of Zr40Hf10Ti4Y1Al10Cu25Ni7Co2Fe1 BMG exhibits characteristics of both the high entropy BMGs and traditional BMGs with a single principal element, leading to its high glass-forming ability.

Crystallization kinetics of Mg–Cu–Yb–Ca–Ag metallic glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsarkov, Andrey A., E-mail: tsarkov@misis.ru; WPI Advanced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577; Zanaeva, Erzhena N.

The paper presents research into a Mg–Cu–Yb system based metallic glassy alloys. Metallic glasses were prepared using induction melting and further injection on a spinning copper wheel. The effect of alloying by Ag and Ca on the glass forming ability and the kinetics of crystallization of Mg–Cu–Yb system based alloys were studied. The differential scanning calorimeter and X-ray diffractometer were used to investigate the kinetics of crystallization and the phase composition of the samples. An indicator of glass forming ability, effective activation energy of crystallization, and enthalpy of mixing were calculated. An increase of the Ca and Ag content hasmore » a positive effect on the glass forming ability, the effective activation energy of crystallization, and the enthalpy of mixing. The highest indicators of the glass forming ability and the thermal stability were found for alloys that contain both alloying elements. The Ag addition suppresses precipitation of the Mg{sub 2}Cu phase during crystallization. A dual-phase glassy-nanocrystalline Mg structure was obtained in Mg{sub 65}Cu{sub 25}Yb{sub 10} and Mg{sub 59.5}Cu{sub 22.9}Yb{sub 11}Ag{sub 6.6} alloys after annealing. Bulk samples with a composite glassy-crystalline structure were obtained in Mg{sub 59.5}Cu{sub 22.9}Yb{sub 11}Ag{sub 6.6} and Mg{sub 64}Cu{sub 21}Yb{sub 9.5}Ag{sub 5.5} alloys. A thermodynamic database for the Mg–Cu–Yb–Ca–Ag system was created to compare the process of crystallization of alloys with polythermal sections of the Mg–Cu–Yb–Ca–Ag phase diagram. - Highlights: • New alloy compositions based on Mg–Cu–Yb system were developed and investigated. • Increasing content of Ag and Ca leads to improving GFA. • Bulk samples with a composite glassy-crystalline structure were obtained. • Thermodynamic database for Mg–Cu–Yb–Ca–Ag system was created.« less

Effect of Ag and Cu Contents on the Age Hardning Behavior of Al-Zn-Mg Alloys

NASA Astrophysics Data System (ADS)

Watanabe, Katsumi; Kawabata, Tokimasa; Ikeno, Susumu; Yoshida, Tomoo; Murakami, Satoshi; Matsuda, Kenji

Al-Zn-Mg alloy has been known as one of the aluminum alloys with the good age-hardening ability and the high strength among commercial aluminum alloys. The mechanical property of the limited ductility, however, is required to further improvement. In this work, three alloys, which were added Cu or Ag into the Al-Zn-Mg-Si alloy, were prepared to compare the effect of the additional elements on the aging behavior. The content of Ag and Cu were 0.2 at.% and 0.2at.%, respectively. The age-hardening behavior and microstructures of those alloys were investigated by hardness measurement, high resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED) technique. Ag or Cu added alloy showed higher peak hardness than Ag or Cu free alloy. According to addition of Ag or Cu, the number density of the precipitates increased than Ag or Cu free alloy.

Surface and bulk effects of K in Cu 1-xK xIn 1-yGa ySe 2 solar cells

DOE PAGES

Muzzillo, Christopher P.; Anderson, Timothy J.

2017-12-29

Two strategies for enhancing photovoltaic (PV) performance in chalcopyrite solar cells were investigated: Cu 1-xK xIn 1-yGa ySe 2 absorbers with low K content (K/(K+Cu), or x ~ 0.07) distributed throughout the bulk, and CuIn 1-yGa ySe 2 absorbers with KIn 1-yGa ySe 2 grown on their surfaces. Distributing K throughout the bulk absorbers improved power conversion efficiency, open-circuit voltage (VOC) and fill factor (FF) for Ga/(Ga+In) of 0, 0.3 and 0.5. Surface KIn 1-yGa ySe 2 and bulk x ~ 0.07 Cu 1-xK xIn 1-yGa ySe 2 films with Ga/(Ga+In), or y of 0.3 and 0.5 also had improvedmore » efficiency, VOC, and FF, relative to CuIn 1-yGa ySe 2 baselines. On the other hand, y ~ 1 absorbers did not benefit from K introduction. Similar to Cu 1-xK xInSe 2, the formation of Cu 1-xK xGaSe 2 alloys was favored at low temperatures and high Na supply by the substrate, relative to the formation of mixed-phase CuGaSe 2 + KGaSe 2. KIn 1-yGa ySe 2 alloys were grown for the first time, as evidenced by X-ray diffraction and ultraviolet/visible spectroscopy. For all Ga/(Ga+In) compositions, the surface KIn 1-yGa ySe 2 absorbers had superior PV performance in buffered and buffer-free devices. However, the bulk x ~ 0.07 absorbers only outperformed the baselines in buffered devices. The data demonstrate that KIn 1-yGa ySe 2 passivates the surface of CuIn 1-yGa ySe 2 to increase efficiency, VOC, and FF, while bulk Cu 1-xK xIn 1-yGa ySe 2 absorbers with x ~ 0.07 enhance efficiency, VOC, and FF by some other mechanism.« less

Surface and bulk effects of K in Cu 1-xK xIn 1-yGa ySe 2 solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muzzillo, Christopher P.; Anderson, Timothy J.

Two strategies for enhancing photovoltaic (PV) performance in chalcopyrite solar cells were investigated: Cu 1-xK xIn 1-yGa ySe 2 absorbers with low K content (K/(K+Cu), or x ~ 0.07) distributed throughout the bulk, and CuIn 1-yGa ySe 2 absorbers with KIn 1-yGa ySe 2 grown on their surfaces. Distributing K throughout the bulk absorbers improved power conversion efficiency, open-circuit voltage (VOC) and fill factor (FF) for Ga/(Ga+In) of 0, 0.3 and 0.5. Surface KIn 1-yGa ySe 2 and bulk x ~ 0.07 Cu 1-xK xIn 1-yGa ySe 2 films with Ga/(Ga+In), or y of 0.3 and 0.5 also had improvedmore » efficiency, VOC, and FF, relative to CuIn 1-yGa ySe 2 baselines. On the other hand, y ~ 1 absorbers did not benefit from K introduction. Similar to Cu 1-xK xInSe 2, the formation of Cu 1-xK xGaSe 2 alloys was favored at low temperatures and high Na supply by the substrate, relative to the formation of mixed-phase CuGaSe 2 + KGaSe 2. KIn 1-yGa ySe 2 alloys were grown for the first time, as evidenced by X-ray diffraction and ultraviolet/visible spectroscopy. For all Ga/(Ga+In) compositions, the surface KIn 1-yGa ySe 2 absorbers had superior PV performance in buffered and buffer-free devices. However, the bulk x ~ 0.07 absorbers only outperformed the baselines in buffered devices. The data demonstrate that KIn 1-yGa ySe 2 passivates the surface of CuIn 1-yGa ySe 2 to increase efficiency, VOC, and FF, while bulk Cu 1-xK xIn 1-yGa ySe 2 absorbers with x ~ 0.07 enhance efficiency, VOC, and FF by some other mechanism.« less

[Urologic and reproductive health status of 30 - 60 years old males: investigation among 1006 men in Shijingshan District of Beijing].

PubMed

He, Li-Jun; Wang, Yi; Zhou, Zhe; Na, Yan-Qun

2012-04-01

To know and find some evidence for the improvement of the urologic and reproductive health of men between 30 and 60 years old. Using stratified random sampling, we conducted a questionnaire investigation on the urologic and reproductive health status of 1 006 men aged from 30 to 60 years old in the Shijingshan District of Beijing, including the unemployed, taxi drivers and office workers. Of the 1006 males investigated, BMI > or = 24 kg/m2 was found in 72.7%, hypertension in 40.0%, abnormal IPSS in 85.5%, abnormal NIH-CPSI in 75.6%, abnormal IIEF-5 in 66.3%, aging male symptoms (AMS) in 10.7%, anxiety in 17.1%, depression in 25.1%, fasting blood-glucose >6.1 mmol/L in 34.9%, total cholesterol >5.07 mmol/L in 44.3% and triglyceride > 1.71 mmol/L in 46.6%; the level of total testosterone was (17.9 +/- 7.2) nmol/L, < 12 nmol/L in 21.3% and <8 nmol/L in 3.4%, and the level of free testosterone was (6.5 +/- 15.1) pmol/L. The urologic and reproductive health status of 30 to 60 years old males in Beijing deserves serious attention from medical workers.

Review of Dextromethorphan 20 mg/Quinidine 10 mg (NUEDEXTA(®)) for Pseudobulbar Affect.

PubMed

Pioro, Erik P

2014-06-01

Pseudobulbar affect (PBA) is a dysfunction of emotional expression characterized by involuntary outbursts of crying or laughing disproportionate or unrelated to mood, occurring in patients with various underlying neurologic disorders. This review describes the clinical data supporting dextromethorphan (DM) hydrobromide combined with quinidine sulfate (Q) as treatment of PBA and briefly surveys the ongoing debates concerning the terminology for dysfunction of emotional expression, as well as the ongoing searches for its brain substrates. Until recently, pharmacologic intervention consisted chiefly of off-label antidepressants. In October 2010, however, DM/Q at 20/10 mg twice daily received approval from the United States Food and Drug Administration for PBA in any setting, and in June 2013, dosages of 20/10 and 30/10 mg twice daily (labeled as 15/9 and 23/9 mg, respectively, DM/Q base) received approval from the European Medicines Agency. DM is an uncompetitive N-methyl-d-aspartate (NMDA) glutamate receptor antagonist, a sigma-1 receptor agonist, and a serotonin and norepinephrine reuptake inhibitor. To block DM hepatic metabolism, thereby increasing DM bioavailability, Quinidine, a cytochrome P450 2D6 inhibitor, is coadministered at a dosage well below those for treating cardiac arrhythmia. Three large-scale DM/Q trials have utilized PBA-episode counts and the Center for Neurologic Study-Lability Scale (CNS-LS), a validated PBA rating scale, to measure efficacy. In a 4-week study of patients with PBA in amyotrophic lateral sclerosis (ALS), DM/Q 30/30 mg was superior to its component drugs. A 12-week, double-blind, placebo-controlled study of DM/Q 30/30 mg showed similar efficacy in patients with PBA in multiple sclerosis (MS). A subsequent 12-week study of patients with PBA and ALS or MS showed superiority to placebo for the 20/10 and 30/10 mg doses. Efficacy was maintained during a 12-week, open-label extension (30/10 mg dose), with further improvement of

Synthesis of AlFeCuCrMg{sub x} (x = 0, 0.5, 1, 1.7) alloy powders by mechanical alloying

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maulik, Ornov; Kumar, Vinod, E-mail: vkt.meta@mnit.ac.in; Adjunct Faculty, Materials Research Centre, Malaviya National Institute of Technology, Jaipur 302017

2015-12-15

Novel AlFeCuCrMg{sub x} (x = 0, 0.5, 1, 1.7 mol) high-entropy alloys (HEAs) were synthesized by mechanical alloying. The effect of Mg content on the phase evolution of HEAs was investigated using X-Ray diffractometry (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) pattern analysis. The particle morphology and composition of HEAs were investigated by scanning electron microscopy (SEM). Thermodynamic parameters were calculated and analyzed to explain the formation of a solid solution. XRD analysis revealed BCC as major phase and FCC as a minor phase in as-milled AlFeCuCr and AlFeCuCrMg{sub 0.5} HEAs. Also, XRD analysis of as-milledmore » AlFeCuCrMg, AlFeCuCrMg{sub 1.7} confirmed the formation of two BCC phases (BCC 1 and BCC 2). TEM–SAED analysis of AlFeCuCrMg{sub x} HEAs concurred with XRD results. Microstructural features and mechanism for solid solution formation have been conferred in detail. Phase formation of the present HEAs has been correlated with calculated thermodynamic parameters. Differential thermal analysis (TGA-DTA) of these alloys confirmed that there is no substantial phase change up to 500 °C. - Highlights: • Novel AlFeCuCrMg{sub x} (x = 0, 0.5, 1, 1.7) HEAs were prepared by mechanical alloying. • Phase evolution and lattice parameter were studied by X-Ray Diffraction. • Crystallite size and lattice microstrain calculated failed to obey the Williamson–Hall method. • Criterions for formation of simple solid solution were compared to the thermodynamic parameters of the present HEAs. • Increase in the Mg concentration in AlMg{sub x}FeCuCr (x = 0, 0.5, 1, 1.7) HEAs supports the formation of BCC phase.« less

Analysis of pulsed-neutron powder diffraction patterns of the icosahedral quasicrystals Pd3Siu and AlCuLiMg (three alloys) as twinned cubic crystals with large units.

PubMed Central

Pauling, L

1991-01-01

The low-Q peaks on three pulsed-neutron powder patterns (total, U differential, and Pd differential) of the icosahedral quasicrystal Pd3SiU have been indexed on the basis of an assumed cubic structure of the crystals that by icosahedral twinning form the quasicrystal. The primitive unit cube is found to have edge length 56.20 A and to contain approximately 12,100 atoms. Similar analyses of pulsed-neutron patterns of Al55Cu10Li35, Al55Cu10Li30Mg5, and Al510Cu125Li235Mg130 give values of the cube edge length 58.3, 58.5, and 58.4 A, respectively, with approximately 11,650 atoms in the unit cube. It is suggested that the unit contains eight complexes in the beta-W positions, plus some small interstitial groups of atoms, with each complex consisting of a centered icosahedron of 13 clusters, each of 116 atoms with the icosahedral structure found in the body-centered cubic crystal Mg32(Al,Zn)49. PMID:11607201

Analysis of pulsed-neutron powder diffraction patterns of the icosahedral quasicrystals Pd3Siu and AlCuLiMg (three alloys) as twinned cubic crystals with large units.

PubMed

Pauling, L

1991-08-01

The low-Q peaks on three pulsed-neutron powder patterns (total, U differential, and Pd differential) of the icosahedral quasicrystal Pd3SiU have been indexed on the basis of an assumed cubic structure of the crystals that by icosahedral twinning form the quasicrystal. The primitive unit cube is found to have edge length 56.20 A and to contain approximately 12,100 atoms. Similar analyses of pulsed-neutron patterns of Al55Cu10Li35, Al55Cu10Li30Mg5, and Al510Cu125Li235Mg130 give values of the cube edge length 58.3, 58.5, and 58.4 A, respectively, with approximately 11,650 atoms in the unit cube. It is suggested that the unit contains eight complexes in the beta-W positions, plus some small interstitial groups of atoms, with each complex consisting of a centered icosahedron of 13 clusters, each of 116 atoms with the icosahedral structure found in the body-centered cubic crystal Mg32(Al,Zn)49.

Research and Development of High-Strength of Al-Zn-Mg-Cu Alloys

NASA Astrophysics Data System (ADS)

Vakhromov, R. O.; Antipov, V. V.; Tkachenko, E. A.

The paper is focused on high-strength alloys (UTS=600-650 MPa, specific strength (UTS/density) 220-230 kN•m/kg) which will allow one to retain aluminum's predominant position during the next 15-20 years as applied in advanced aircraft primary structures. Parameters of microstructure (dispersoids, precipitates, degree of recrystallisation, grain size) and properties of semiproducts were studied in dependence on content of base alloying elements in chemical compositions of alloys (total sum of Zn+Mg+Cu — higher than 10 % mass). Contribution of minor additions (Zr, Sc, Ag) to strengthening and creation of improved combination of service properties was investigated. Evolution of phase composition and properties was studied as a dependence of different aging treatments.

Effects of Fabrication Parameters on Interface of Zirconia and Ti-6Al-4V Joints Using Zr55Cu30Al10Ni5 Amorphous Filler

NASA Astrophysics Data System (ADS)

Liu, Yuhua; Hu, Jiandong; Shen, Ping; Guo, Zuoxing; Liu, Huijie

2013-09-01

ZrO2 was brazed to Ti-6Al-4V using a Zr55Cu30Al10Ni5 (at.%) amorphous filler in a high vacuum at 1173-1273 K. The influences of brazing temperature, holding time, and cooling rate on the microstructure and shear strength of the joints were investigated. The interfacial microstructures can be characterized as ZrO2/ZrO2- x + TiO/(Zr,Ti)2(Cu,Ni)/(Zr,Ti)2(Cu,Ni,Al)/acicular Widmanstäten structure/Ti-6Al-4V. With the increase in the brazing temperature, both the thickness of the ZrO2- x + TiO layer and the content of the (Zr,Ti)2(Cu,Ni) phase decreased. However, the acicular Widmanstäten structure gradually increased. With the increase in the holding time, the (Zr,Ti)2(Cu,Ni) phase decreased, and the thickness of the (Zr,Ti)2(Cu,Ni) + (Zr,Ti)2(Cu,Ni,Al) layer decreased. In addition, cracks formed adjacent to the ZrO2 side under rapid cooling. The microstructures produced under various fabrication parameters directly influence the shear strength of the joints. When ZrO2 and Ti-6Al-4V couples were brazed at 1173 K for 10 min and then cooled at a rate of 5 K/min, the maximum shear strength of 95 MPa was obtained.

Shock-wave studies of anomalous compressibility of glassy carbon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molodets, A. M., E-mail: molodets@icp.ac.ru; Golyshev, A. A.; Savinykh, A. S.

2016-02-15

The physico-mechanical properties of amorphous glassy carbon are investigated under shock compression up to 10 GPa. Experiments are carried out on the continuous recording of the mass velocity of compression pulses propagating in glassy carbon samples with initial densities of 1.502(5) g/cm{sup 3} and 1.55(2) g/cm{sup 3}. It is shown that, in both cases, a compression wave in glassy carbon contains a leading precursor with amplitude of 0.135(5) GPa. It is established that, in the range of pressures up to 2 GPa, a shock discontinuity in glassy carbon is transformed into a broadened compression wave, and shock waves are formedmore » in the release wave, which generally means the anomalous compressibility of the material in both the compression and release waves. It is shown that, at pressure higher than 3 GPa, anomalous behavior turns into normal behavior, accompanied by the formation of a shock compression wave. In the investigated area of pressure, possible structural changes in glassy carbon under shock compression have a reversible character. A physico-mechanical model of glassy carbon is proposed that involves the equation of state and a constitutive relation for Poisson’s ratio and allows the numerical simulation of physico-mechanical and thermophysical properties of glassy carbon of different densities in the region of its anomalous compressibility.« less

[Y/Mg] stellar dating calibration

NASA Astrophysics Data System (ADS)

Titarenko, A.; Recio-Blanco, A.; de Laverny, P.; Hayden, M.; Guiglion, G.; Worley, C.

2018-04-01

Gaia DR1 has opened a new era of stellar age dating, that is crucial for many astrophysical objectives. In addition, the Gaia based isochrone fitting ages can be compared to other chemical clocks like the [Y/Mg] one (Nissen et al. 2015). In our work we have used ESO archived data of the AMBRE project (de Laverny et al. 2013) for UVES spectra, in order to evaluate the age [Y/Mg] abundance correlation for turn off stars. 310 turn off stars of the UVES-archive (setups 564 and 580) are included in the TGAS database. Isochrone fitting ages were derived. We have applied the GAUGUIN procedure for those stars to derive the Mg and the Y abundances. As the result we present the [Y/Mg] vs stellar age dependence for ~40 TO-stars.

Thermoelectric and Transport Properties of Delafossite CuCrO2:Mg Thin Films Prepared by RF Magnetron Sputtering

PubMed Central

Sinnarasa, Inthuga; Thimont, Yohann; Presmanes, Lionel; Barnabé, Antoine; Tailhades, Philippe

2017-01-01

P-type Mg doped CuCrO2 thin films have been deposited on fused silica substrates by Radio-Frequency (RF) magnetron sputtering. The as-deposited CuCrO2:Mg thin films have been annealed at different temperatures (from 450 to 650 °C) under primary vacuum to obtain the delafossite phase. The annealed samples exhibit 3R delafossite structure. Electrical conductivity σ and Seebeck coefficient S of all annealed films have been measured from 40 to 220 °C. The optimized properties have been obtained for CuCrO2:Mg thin film annealed at 550 °C. At a measurement temperature of 40 °C, this sample exhibited the highest electrical conductivity of 0.60 S·cm−1 with a Seebeck coefficient of +329 µV·K−1. The calculated power factor (PF = σS²) was 6 µW·m−1·K−2 at 40 °C and due to the constant Seebeck coefficient and the increasing electrical conductivity with measurement temperature, it reached 38 µW·m−1·K−2 at 220 °C. Moreover, according to measurement of the Seebeck coefficient and electrical conductivity in temperature, we confirmed that CuCrO2:Mg exhibits hopping conduction and degenerates semiconductor behavior. Carrier concentration, Fermi level, and hole effective mass have been discussed. PMID:28654011

Structure refinement of Zn and Pr-doped Y-Ba-Cu-oxides

NASA Astrophysics Data System (ADS)

Naik, M. S.; Sarode, P. R.; Priolkar, K. R.; Prabhu, R. B.

2018-05-01

Superconducting compounds of composition Y0.9 Pr0.1Ba2 [Cu1-yZny]3O7-δ (0 ≤ y ≤ 0.10) have been synthesized. The structure of these materials has been studied using powder X-ray diffraction technique and refinement has been carried out by using Rietveld refinement procedure. It has been shown that all these compounds crystallize in orthorhombic structure with slight change in c parameter. Increase of parameter O(2) and decrease of parameter O(3)suggest the changes in the Cu-O2 plane of these orthorhombic materials on Zn substitution.

Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films

NASA Astrophysics Data System (ADS)

Zhang, H.; Gauquelin, N.; McMahon, C.; Hawthorn, D. G.; Botton, G. A.; Wei, J. Y. T.

2018-03-01

It is known that solid-state reaction in high-pressure oxygen can stabilize high-oxidation phases of Y-Ba-Cu-O superconductors in powder form. We extend this superoxygenation concept of synthesis to thin films which, due to their large surface-to-volume ratio, are more reactive thermodynamically. Epitaxial thin films of YBa2Cu3O7 -δ grown by pulsed laser deposition are annealed at up to 700 atm O2 and 900 ∘C , in conjunction with Cu enrichment by solid-state diffusion. The films show the clear formation of Y2Ba4Cu7O15 -δ and Y2Ba4Cu8O16 as well as regions of YBa2Cu5O9 -δ and YBa2Cu6O10 -δ phases, according to scanning transmission electron microscopy, x-ray diffraction, and x-ray absorption spectroscopy. Similarly annealed YBa2Cu3O7 -δ powders show no phase conversion. Our results demonstrate a route of synthesis towards discovering more complex phases of cuprates and other superconducting oxides.

Comparison of serum Concentration of Se, Pb, Mg, Cu, Zn, between MS patients and healthy controls

PubMed Central

Alizadeh, Anahita; Mehrpour, Omid; Nikkhah, Karim; Bayat, Golnaz; Espandani, Mahsa; Golzari, Alireza; Jarahi, Lida; Foroughipour, Mohsen

2016-01-01

Introduction Multiple Sclerosis (MS) is defined as one of the inflammatory autoimmune disorders and is common. Its exact etiology is unclear. There are some evidences on the role of environmental factors in susceptible genetics. The aim of this study is to evaluate the possible role of Selenium, Zinc, Copper, Lead and Magnesium metals in Multiple Sclerosis patients. Methods In the present analytical cross-sectional study, 56 individuals including 26 patients and 30 healthy controls were enrolled in the evaluation. The serum level of Se, Zn, Cu, Pb were quantified in graphite furnace conditions and flame conditions by utilizing an atomic absorption Perkin Elmer spectrophotometer 3030. The serum levels of Mg were measured by auto analyzer 1500 BT. The mean level of minerals (Zn, Pb, Cu, Mg, Se) in serum samples were compared in both cases and controls. The mean level of minerals (Zn, Pb, Cu, Mg, Se) in serum samples were compared in both cases and controls by using independent-samples t-test for normal distribution and Mann-Whitney U test as a non-parametric test. All statistical analyses were carried out using SPSS 11.0. Results As well as the Zn, Cu, and Se, there was no significant difference between MS patients and healthy individuals in Pb concentrations (p-value = 0.11, 0.14, 0.32, 0.20 respectively) but the level of Mg was significantly different (p= 0.001). Conclusion All serum concentrations of Zn, Pb, Se, Cu in both groups were in normal ranges and there was no difference in MS patients compared with the healthy group who were matched in genetics. Blood level of Mg was significantly lower in MS patients. But it should be noted that even with the low level of serum magnesium in MS patients, this value is still in the normal range. PMID:27757186

The effect of milling time on the synthesis of Cu{sub 54}Mg{sub 22}Ti{sub 18}Ni{sub 6} alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kursun, C., E-mail: celalkursun@ksu.edu.tr; Gogebakan, M., E-mail: gogebakan@ksu.edu.tr

In the present work, nanocrystalline Cu{sub 54}Mg{sub 22}Ti{sub 18}Ni{sub 6} alloy was produced by mechanical alloying from mixtures of pure crystalline Cu, Mg, Ti and Ni powders using a Fritsch planetary ball mill with a ball to powder ratio of 10:1. Morphological changes, microstructural evolution and thermal behaviour of the Cu-Mg-Ti-Ni powders at different stages of milling were characterised by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray detection (SEM/EDX) and differential thermal analysis (DTA). This alloy resulted in formation of single phase solid solution with FCC structure α-Cu (Mg, Ti, Ni) after 80 h of milling. In the initialmore » stage of milling different sized and shaped elemental powders became uniform during mechanical alloying. The homogeneity of the Cu{sub 54}Mg{sub 22}Ti{sub 18}Ni{sub 6} alloy increased with increasing milling time. The EDX result also confirmed the compositional homogeneity of the powder alloy. The crystallite size of alloy was calculated below 10 nm from XRD data.« less

Investigations of YBa2Cu3O y films sputtered onto a substrate of amorphous quartz with a platinum buffer layer

NASA Astrophysics Data System (ADS)

Blinova, Yu. V.; Snigirev, O. V.; Porokhov, N. V.; Evlashin, S. A.

2017-10-01

Results of investigations using X-ray diffraction and scanning electron microscopy of composite materials made from YBa2Cu3O y films sputtered (using various regimes) onto a substrate of amorphous quartz with a platinum buffer layer, have been given.

Relationship between the Cu-spin fluctuation and superconductivity in La2-xSrxCu1-y(Zn, Ni)yO4 (x = 0.15) studied by the μSR and magnetic-susceptibility

NASA Astrophysics Data System (ADS)

Adachi, T.; Oki, N.; Risdiana; Yairi, S.; Koike, Y.; Watanabe, I.

2007-09-01

We have investigated effects of Zn and Ni on the Cu-spin dynamics and superconductivity from the zero-field muon-spin-relaxation (ZF-μSR) and magnetic-susceptibility, χ, measurements for the optimally doped La 2- xSr xCu 1- y(Zn, Ni) yO 4 with x = 0.15, changing y finely up to 0.10. The ZF-μSR measurements have revealed that, in the Zn-substituted case, the magnetic correlation between Cu-spins starts to develop at y = 0.01 with increasing y, followed by the formation of a magnetic order at y = 0.02-0.03. In the Ni-substituted case, on the other hand, the magnetic correlation starts to develop at y = 0.02-0.03. These results indicate that the formation of a magnetic order requires a larger amount of Ni than that of Zn, which is consistent with our previous result for x = 0.13. The χ measurements have revealed that the superconducting volume fraction strongly decreases by a small amount of Zn and its decrease is stronger than that by a small amount of Ni. According to the stripe model, therefore, it is concluded that, even for x = 0.15, the dynamical stripe correlations of spins and holes are pinned and stabilized by Zn and Ni, leading to the formation of the static stripe order and the suppression of superconductivity.

On the origin of bulk glass forming ability in Cu-Hf, Zr alloys

NASA Astrophysics Data System (ADS)

Ristić, Ramir; Zadro, Krešo; Pajić, Damir; Figueroa, Ignacio A.; Babić, Emil

2016-04-01

Understanding the formation of bulk metallic glasses (BMG) in metallic systems and finding a reliable criterion for selection of BMG compositions are among the most important issues in condensed-matter physics and material science. Using the results of magnetic susceptibility measurements performed on both amorphous and crystallized Cu-Hf alloys (30-70 at% Cu) we find a correlation between the difference in magnetic susceptibilities of corresponding glassy and crystalline alloys and the variation in the glass forming ability (GFA) in these alloys. Since the same correlation can be inferred from data for the properties associated with the electronic structure of Cu-Zr alloys, it seems quite general and may apply to other glassy alloys based on early and late transition metals. This correlation is plausible from the free-energy considerations and provides a simple way to select the compositions with high GFA.

Kinetic parameters and structural variations in Cu-Al-Mn and Cu-Al-Mn-Mg shape memory alloys

NASA Astrophysics Data System (ADS)

Canbay, Canan Aksu

2017-02-01

In this work polycrystalline Cu-Al-Mn and Cu-Al-Mn-Mg SMAs were fabricated by arc melting. The thermal analysis was made to determine the characteristic transformation temperatures of the samples and kinetic parameters. Also the effect of Mg on transformation temperatures and kinetic parameters detected. The structural analysis was made to designate the diffraction planes of martensite phase at room temperature and this was supported by optical measurement observations.

CeLa enhanced corrosion resistance of Al-Cu-Mn-Mg-Fe alloy for lithium battery shell

NASA Astrophysics Data System (ADS)

Du, Jiandi; Ding, Dongyan; Zhang, Wenlong; Xu, Zhou; Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua; Chen, Renzong; Huang, Yuanwei; Tang, Jinsong

2017-11-01

Effects of CeLa addition on the localized corrosion and electrochemical corrosion behavior of Al-Cu-Mn-Mg-Fe lithium battery shell alloy were investigated by immersion testing and electrochemical testing in 0.6 M NaCl solution at different temperatures. Experimental results indicated that CeLa addition resulted in the formation of AlCuCe/La (Al8Cu4Ce and Al6Cu6La) local cathodes and corrosion activity of the main intermetallic particles decreased in the order of Al2CuMg, AlCuCe/La, Al6(Mn, Fe). Corrosion potential shifted positively due to CeLa alloying. Corrosion current density of the CeLa-containing alloy was lower than that of the CeLa-free alloy at room temperature. At room temperature, there was no obvious surface passivation for both alloys. At 80 °C CeLa addition resulted in a wide passive region at the anode polarization region. Electrochemical impedance spectroscopy (EIS) analysis also indicated that corrosion resistance of the CeLa-containing alloy was much higher than that of the CeLa-free alloy.

The Effect of Palladium Additions on the Solidus/Liquidus Temperatures and Wetting Properties of Ag-CuO Based Air Brazes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darsell, Jens T.; Weil, K. Scott

2007-05-16

As a means of increasing the use temperature of ceramic-ceramic and ceramic-metal air brazes, palladium was investigated as possible ternary addition to the currently employed silver - copper oxide system. The silver component was directly substituted with palladium to form the following series of alloys: (100-y)[(100-z)Pd - (z)Ag] - (y)CuOx where y = 0 - 34 mol% CuOx, z = 50 - 100 mol% silver, and x = 0, 0.5, and 1, denoting copper metal, Cu2O, or CuO. From differential scanning calorimetry, it was determined that the addition of palladium causes an increase in the solidus and liquidus temperatures ofmore » the resulting Pd-Ag-CuO brazes. In general, the liquidus was found to increase by approximately 220°C for the (100-y)(25Pd - 75Ag) - (z)CuOx filler metal compositions relative to comparable Ag-CuOx alloys. Likewise, the solidus was found to increase for these alloys, respectively by 185°C and 60°C, respectively for CuOx contents of y = 0 - 1mol% and 4 - 10 mol%. For the (100-y)(50Pd - 50Ag) - (y)CuOx alloys, the solidus increased between 280 - 390°C over a copper oxide compositional range of x = 0 to 8 mol%. It was determined from sessile drop experiments conducted on alumina substrates that in all cases the palladium causes an increase in the wetting angle relative to the corresponding binary braze. Alloy compositions of (100-y)(25Pd - 75Ag) - (y)CuOx displayed increased wetting angles of 5-20° relative to comparable binary compositions. (100-y)(50Pd - 50Ag) - (y)CuOx alloys exhibited an increase in contact angle of 10-60° and compositions containing less than 10 mol% CuOx were not able to wet the substrate. Scanning electron microscopy indicated that the microstructure of the braze consists of discrete CuOx precipitates in an alloyed silver-palladium matrix. In both the binary and ternary filler metal formulations, a reaction layer consisting of CuAlO2 was observed along the interface with the alumina substrate. This reaction product appears to be

Enhanced critical currents in (Gd,Y)Ba2Cu3Ox superconducting tapes with high levels of Zr addition

NASA Astrophysics Data System (ADS)

Selvamanickam, V.; Chen, Y.; Shi, T.; Liu, Y.; Khatri, N. D.; Liu, J.; Yao, Y.; Xiong, X.; Lei, C.; Soloveichik, S.; Galstyan, E.; Majkic, G.

2013-03-01

The critical current and structural properties of (Gd,Y)BaCuO tapes made by metal organic chemical vapor deposition (MOCVD) with Zr addition levels up to 30 at.% have been investigated. The reduction in critical current beyond the previously optimized Zr addition level of 7.5 at.% was found to be due to structural deterioration of the (Gd,Y)Ba2Cu3Ox film. By a modified MOCVD process, enhanced critical current densities have been achieved with high levels of Zr addition, including 3.83 MA cm-2 in 15 at.% Zr-added 1.1 μm thick film at 77 K in zero magnetic field. Critical currents as high as 1072 A/12 mm have been reached in (Gd,Y)BaCuO tapes with 15 at.% Zr addition at 30 K in a field of 3 T applied perpendicular to the tape, corresponding to a pinning force value of 268 GN m-3. The enhanced critical currents achievable with a high density of nanoscale defects by employing high levels of second-phase additions enable the performance targets needed for the use of HTS tapes in coil applications involving high magnetic fields at temperatures below 50 K to be met.

Compatibilities of YBa2Cu3O(9-delta) type phase in quintenary systems Y-Ba-Cu-O-X (impurity)

NASA Technical Reports Server (NTRS)

Karen, P.; Braaten, O.; Fjellvag, H.; Kjekshus, A.

1991-01-01

Isothermal phase diagrams at various oxygen pressures were studied by powder diffraction and chemical analytical methods. The components, Y, Ba, Cu, and O (specifically O2, O2-, and O2 sup 2-) are treated, together with C (specifically CO2 and CO2 sup 2-), alkaline metals, Mg, alkaline earths, Sc, 3-d and 4-f elements. Effects of the substitutions at the structural sites of YBa2Cu3O(9-delta) on T sub c are discussed with respect to changes in crystallochemical characteristics of the substituted phase and to the nature of the substituents.

Understanding glass-forming ability through sluggish crystallization of atomically thin metallic glassy films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Y. T.; Cao, C. R.; Huang, K. Q.

2014-08-04

The glass-forming ability (GFA) of an alloy, closely related to its ability to resist crystallization, is a crucial issue in condensed matter physics. So far, the studies on GFA are mostly statistical and empirical guides. Benefiting from the ultrahigh thermal stability of ultrathin metallic glassy film and high resolution spherical aberration-corrected transmission electron microscope, the crystallization of atomically thin ZrCu and its microalloyed ZrCuAl glasses with markedly different GFA was investigated at the atomic scale. We find the Zr diffusivity estimated from the density of nuclei is dramatically decreased by adding of Al, which is the major reason for themore » much better GFA of the ZrCuAl metallic glass.« less

Texture and mechanical properties of Al-0.5Mg-1.0Si-0.5Cu alloy sheets manufactured via a cross rolling method

NASA Astrophysics Data System (ADS)

Jeon, Jae-Yeol; Son, Hyeon-Taek; Woo, Kee-Do; Lee, Kwang-Jin

2012-04-01

The relationship between the texture and mechanical properties of 6xxx aluminum alloy sheets processed via cross rolling was investigated. The microstructures of the conventional rolled and cross rolled sheets after annealing were analyzed using optical micrographs (OM). The texture distribution across the thickness in the Al-Mg-Si-Cu alloy, conventional rolled sheets, and cross rolled sheets both before and after annealing was investigated via X-ray texture measurements. The texture was analyzed in three layers from the surface to the center of the sheet. The β-fiber texture of the conventional rolled sheet was typical of the texture obtained using aluminumoll ring. After annealing, the typical β-fiber orientations were changed to recrystallization textures: cube{001}<100> and normal direction (ND)-rotated cubes. However, the texture of the cross rolled sheet was composed of an asymmetrical, rolling direction (RD)-rotated cubes. After annealing, the asymmetrical orientations in the cross rolled sheet were changed to a randomized texture. The average R-value of the annealed cross rolled sheets was higher than that of the conventional rolled sheets. The limit dome height (LDH) test results demonstrated that cross rolling is effective in improving the formability of the Al-Mg-Si-Cu alloy sheets.

Detailed low-energy electron diffraction analysis of the (4×4) surface structure of C60 on Cu(111): Seven-atom-vacancy reconstruction

NASA Astrophysics Data System (ADS)

Xu, Geng; Shi, Xing-Qiang; Zhang, R. Q.; Pai, Woei Wu; Jeng, H. T.; Van Hove, M. A.

2012-08-01

A detailed and exhaustive structural analysis by low-energy electron diffraction (LEED) is reported for the C60-induced reconstruction of Cu(111), in the system Cu(111) + (4 × 4)-C60. A wide LEED energy range allows enhanced sensitivity to the crucial C60-metal interface that is buried below the 7-Å-thick molecular layer. The analysis clearly favors a seven-Cu-atom vacancy model (with Pendry R-factor Rp = 0.376) over a one-Cu-atom vacancy model (Rp = 0.608) and over nonreconstructed models (Rp = 0.671 for atop site and Rp = 0.536 for hcp site). The seven-Cu-atom vacancy forms a (4 × 4) lattice of bowl-like holes. In each hole, a C60 molecule can nestle by forming strong bonds (shorter than 2.30 Å) between 15 C atoms of the molecule and 12 Cu atoms of the outermost and second Cu layers.

Proton and deuteron double differential cross sections at angles from 10 deg to 60 deg from Be, C, Al, Fe, Cu, Ge, W, and Pb under 558-MeV-proton irradiation

NASA Technical Reports Server (NTRS)

Beck, S. M.; Powell, C. A.

1976-01-01

The double differential cross sections for the production of protons and deuterons from targets of Be, C, Al, Fe, Cu, Ge, W, and Pb were obtained at laboratory angles of scatter of 10, 20, 30, 40, 50, and 60 degrees for 558-MeV incident protons. The position of the quasi-elastic peak, discernible in the cross sections up to approximately 40 degrees, corresponded closely to the theoretical predictions for proton-proton elastic scattering at 558 MeV. The mean ratio of deuteron to proton energy-integrated cross sections was 0.056 + or - 0.008. The dependence of energy-integrated cross sections for both protons and deuterons on target mass number A varied from A to the 1/3 power at 10 degrees to A to the 2/3 power above approximately 30 degrees. The ratio of energy-integrated deuteron cross sections for quasielastic processes to that for reactions yielding a deuteron-pi-meson pair was approximately 10 percent.

Effects of Sn Addition on the Microstructures and Mechanical Properties of Mg-6Zn-3Cu- xSn Magnesium Alloys

NASA Astrophysics Data System (ADS)

Zhang, Tao; Shen, Jun; Sang, Jia-Xin; Li, Yang; He, Pei-Pei

2015-08-01

In this paper, Mg-6Zn-3Cu- xSn (ZC63- xSn) magnesium alloys with different Sn contents (0, 1, 2, 4 wt pct) were fabricated and subjected to different heat treatments. The microstructures and mechanical properties of the obtained ZC63- xSn samples were investigated by optical microscopy, X-ray diffraction, scanning electron microscopy, Vickers hardness testing, and tensile testing. It was found that the As-cast Mg-6Zn-3Cu (ZC63) magnesium alloy mainly contained α-Mg grains and Mg(Zn,Cu) particles. Sn dissolved in α-Mg grains when Sn content was below 2 wt pct while Mg2Sn phase forms in the case of Sn content was above 4 wt pct. Addition of Sn refined both α-Mg grains and Mg(Zn,Cu) particles, and increased the volume fraction of Mg(Zn,Cu) particles. Compared with the Sn-free alloy, the microhardness of Sn-containing alloys increased greatly and that of As-extrude ZC63-4Sn sample achieved the highest value. The strength of ZC63 magnesium alloy was significantly enhanced because of Sn addition, which was attributed to grain refinement strengthening, solid solution strengthening, and precipitation strengthening. Furthermore, the ultimate yield stress, yield strength, and elongation of ZC63- xSn magnesium alloys were increased owing to the deceasing grain size induced by extrusion process.

Effect of γ-rays irradiation on the structural, magnetic, and electrical properties of Mg-Cu-Zn and Ni-Cu-Zn ferrites

NASA Astrophysics Data System (ADS)

Assar, S. T.; Abosheiasha, H. F.; El Sayed, A. R.

2017-01-01

Nanoparticles of Ni0.35Cu0.15Zn0.5Fe2O4 and Mg0.35Cu0.15Zn0.5Fe2O4, have been synthesized by citrate precursor method. Then some of the prepared samples have been irradiated by γ-rays of 60Co radioactive source at room temperature with doses of 1 Mrad and 2 Mrad, at a dose rate of 0.1 Mrad/h to study the effect of γ-rays irradiation on some structural, magnetic and electrical properties of the samples. The X-ray diffraction analysis (XRD), transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer measurements have been used to investigate the samples. The XRD results show that the irradiation has caused a decrease in the crystallite size and the measured density and an increase in the porosity, specific surface area, and microstrain in the case of Ni-Cu-Zn ferrite whereas in the case of Mg-Cu-Zn ferrite the reverse trend has been noticed. The lattice constant of the investigated samples has been increased with the increase of irradiation due to the conversion of Fe3+ (0.67 Å) to Fe2+ (0.76 Å). The magnetization results show an increase in saturation and remnant magnetizations for the two prepared ferrites after γ-rays irradiation. The main reason of this behavior is most probably due to the redistribution of the cations between A and B sites. The cation distribution has been proposed such that the values of theoretical and experimental magnetic moment are identical and increase as the magnetization increases. Moreover, a theoretical estimation of the lattice constant has been calculated on the basis of the proposed cation distribution for each sample and compared with the corresponding experimental values obtained by XRD analysis; where they have been found in a good agreement with each other. This can be considered as another confirmation of the validity of the cation distribution. Moreover, the cation distribution is thought to play an important role in increasing the values of dc conductivity of all samples

Sequentially evaporated thin Y-Ba-Cu-O superconductor films: Composition and processing effects

NASA Technical Reports Server (NTRS)

Valco, George J.; Rohrer, Norman J.; Warner, Joseph D.; Bhasin, Kul B.

1988-01-01

Thin films of YBa2Cu3O(7-beta) have been grown by sequential evaporation of Cu, Y, and BaF2 on SrTiO3 and MgO substrates. The onset temperatures were as high as 93 K while T sub c was 85 K. The Ba/Y ratio was varied from 1.9 to 4.0. The Cu/Y ratio was varied from 2.8 to 3.4. The films were then annealed at various times and temperatures. The times ranged from 15 min to 3 hr, while the annealing temperatures used ranged from 850 C to 900 C. A good correlation was found between transition temperature (T sub c) and the annealing conditions; the films annealed at 900 C on SrTiO3 had the best T sub c's. There was a weaker correlation between composition and T sub c. Barium poor films exhibitied semiconducting normal state resistance behavior while barium rich films were metallic. The films were analyzed by resistance versus temperature measurements and scanning electron microscopy. The analysis of the films and the correlations are reported.

Effect of Cr, Ti, V, and Zr Micro-additions on Microstructure and Mechanical Properties of the Al-Si-Cu-Mg Cast Alloy

NASA Astrophysics Data System (ADS)

Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

2016-05-01

Uniaxial static and cyclic tests were used to assess the role of Cr, Ti, V, and Zr additions on properties of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in as-cast and T6 heat-treated conditions. The microstructure of the as-cast alloy consisted of α-Al, eutectic Si, and Cu-, Mg-, and Fe-rich phases Al2.1Cu, Al8.5Si2.4Cu, Al5.2CuMg4Si5.1, and Al14Si7.1FeMg3.3. In addition, the micro-sized Cr/Zr/Ti/V-rich phases Al10.7SiTi3.6, Al6.7Si1.2TiZr1.8, Al21.4Si3.4Ti4.7VZr1.8, Al18.5Si7.3Cr2.6V, Al7.9Si8.5Cr6.8V4.1Ti, Al6.3Si23.2FeCr9.2V1.6Ti1.3, Al92.2Si16.7Fe7.6Cr8.3V1.8, and Al8.2Si30.1Fe1.6Cr18.8V3.3Ti2.9Zr were present. During solution treatment, Cu-rich phases were completely dissolved, while the eutectic silicon, Fe-, and Cr/Zr/Ti/V-rich intermetallics experienced only partial dissolution. Micro-additions of Cr, Zr, Ti, and V positively affected the alloy strength. The modified alloy in the T6 temper during uniaxial tensile tests exhibited yield strength of 289 MPa and ultimate tensile strength of 342 MPa, being significantly higher than that for the Al-Si-Cu-Mg base. Besides, the cyclic yield stress of the modified alloy in the T6 state increased by 23 pct over that of the base alloy. The fatigue life of the modified alloy was substantially longer than that of the base alloy tested using the same parameters. The role of Cr, Ti, V, and Zr containing phases in controlling the alloy fracture during static and cyclic loading is discussed.

Superconducting transition temperature in the Y(1-x)M(x)Ba2Cu3O(y) system

NASA Astrophysics Data System (ADS)

Suzuki, Takeyuki; Yamazaki, Tsutomu; Sekine, Ryuuta; Koukitsu, Akinori; Seki, Hisashi

1989-04-01

Experimental results are presented for the inclusion of compositional additives, M, to the sintered high-temperature superconductor Y(1-x)M(x)Ba2Cu3O(y); M can be the oxides of Mg, Ce, Gd, Yb, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, and Te, as well as Li, Na, K, Ca, Sr, and La carbonates. Temperature dependence of the electrical resistance was measured down to about 80 K. Attention is given to the influence of ionic radius and the valence of the M species.

Influence of compositions on thermal stability and thermodynamic parameter in Ca-Mg-Cu bulk metallic glasses

NASA Astrophysics Data System (ADS)

Deshmukh, A. A.; Khond, A. A.; Palikundwar, U. A.

2018-05-01

In the present manuscript, influence of compositions on thermal stability (ΔTx) and thermodynamic parameter PHSS of Ca-Mg-Cu bulk metallic glasses (BMGs) is evaluated. The statistical approach of regression analysis is adopted to investigate the compositional variation with ΔTx and PHSS. It is found that calcium (Ca) and copper (Cu) content has goodlinear relationship with ΔTx and PHSS. It is observed that with increase in Ca content, ΔTx and PHSS decreases. On the other hand, increase in Cu content, both ΔTx and PHSS increases. Correlation fit of magnesium (Mg) content with both ΔTx and PHSS is very poor. A graph is also plotted to understand the relationship between ΔTx and PHSS. Result of the relationship between ΔTx and PHSS reveals that the alloy composition having more negative value of PHSS will have more stability. Therefore, compositions with more negative value of PHSS will lead to ease of BMGs formation in Ca-Mg-Cu alloy system and hence more stable it will be. It is expected that these results will be supportive in identifying the compositions having these elements for making BMGs.

Influence of Cu Addition on the Structure, Mechanical and Corrosion Properties of Cast Mg-2%Zn Alloy

NASA Astrophysics Data System (ADS)

Lotfpour, M.; Emamy, M.; Dehghanian, C.; Tavighi, K.

2017-05-01

Effects of different concentrations of Cu on the structure, mechanical and corrosion properties of Mg-2%Zn alloy were studied by the use of x-ray diffraction, optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, standard tensile testing, polarization and electrochemical impedance spectroscopy (EIS) measurements. The average grain size of the alloy decreased from above 1000 μm to about 200 μm with 5 wt.% Cu addition in as-cast condition. Microstructural studies revealed that Mg-2Zn- xCu alloys matrix typically consists of primary α-Mg and MgZnCu and Mg(Zn,Cu)2 intermetallics which are mainly found at the grain boundaries. The results obtained from mechanical testing ascertained that Cu addition increased the hardness values significantly. Although the addition of 0.5 wt.% Cu improved the ultimate tensile strength and elongation values, more Cu addition (i.e., 5 wt.%) weakened the tensile properties of the alloy by introducing semi-continuous network of brittle intermetallic phases. Based on polarization test results, it can be concluded that Cu eliminates a protective film on Mg-2%Zn alloy surface. Among Mg-2%Zn- x%Cu alloys, the one containing 0.1 wt.% Cu exhibited the best anti-corrosion property. However, further Cu addition increased the volume fraction of intermetallics culminating in corrosion rate enhancement due to the galvanic couple effect. EIS and microstructural analysis also confirmed the polarization results.

Tension-compression asymmetry of a rolled Mg-Y-Nd alloy

NASA Astrophysics Data System (ADS)

Song, Bo; Pan, Hucheng; Ren, Weijie; Guo, Ning; Wu, Zehong; Xin, Renlong

2017-07-01

In this work, tension and compression deformation behaviors of rolled and aged Mg-Y-Nd alloys were investigated. The microstructure evolution and plastic deformation mechanism during tension and compression were analyzed by combined use of electron backscatter diffraction and a visco-plastic self-consistent crystal plasticity model. The results show that both rolled and aged Mg-Y-Nd sheets show an extremely low yield asymmetry. Elimination of yield asymmetry can be ascribed to the tilted basal texture and suppression of {10-12} twinning. The rolled sheet has almost no yield asymmetry, however exhibits a remarkable strain-hardening behavior asymmetry. Compressed sample shows lower initial strain hardening rate and keeps higher strain hardening rate at the later stage compared with tension. The strain-hardening asymmetry can be aggravated by aging at 280 C. It is considered the limited amount of twins in compression plays the critical role in the strain hardening asymmetry. Finally, the relevant mechanism was analyzed and discussed.

Facile green in situ synthesis of Mg/CuO core/shell nanoenergetic arrays with a superior heat-release property and long-term storage stability.

PubMed

Zhou, Xiang; Xu, Daguo; Zhang, Qiaobao; Lu, Jian; Zhang, Kaili

2013-08-14

We report a facile green method for the in situ synthesis of Mg/CuO core/shell nanoenergetic arrays on silicon, with Mg nanorods as the core and CuO as the shell. Mg nanorods are first prepared by glancing angle deposition. CuO is then deposited around the Mg nanorods by reactive magnetron sputtering to realize the core/shell structure. Various characterization techniques are used to investigate the prepared Mg/CuO core/shell nanoenergetic arrays, including scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and thermal analysis. Uniform mixing and intimate contact between the Mg nanorods and CuO are confirmed from both visual inspection of the morphological images and analyses of the heat-release curves. The nanoenergetic arrays exhibit a low-onset reaction temperature (∼300 °C) and high heat of reaction (∼3400 J/g). Most importantly, the nanoenergetic arrays possess long-term storage stability resulting from the stable CuO shell. This study provides a potential general strategy for the synthesis of various Mg nanorod-based stable nanoenergetic arrays.

7 CFR 30.60 - Reports.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Reports. 30.60 Section 30.60 Agriculture Regulations... AND STANDARDS Reports § 30.60 Reports. Within fifteen (15) days after January 1, April 1, July 1, and... from him, reports showing the following information as to leaf tobacco in leaf and sheet form: (a...

7 CFR 30.60 - Reports.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Reports. 30.60 Section 30.60 Agriculture Regulations... AND STANDARDS Reports § 30.60 Reports. Within fifteen (15) days after January 1, April 1, July 1, and... from him, reports showing the following information as to leaf tobacco in leaf and sheet form: (a...

Cu2O-based solar cells using oxide semiconductors

NASA Astrophysics Data System (ADS)

Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro

2016-01-01

We describe significant improvements of the photovoltaic properties that were achieved in Al-doped ZnO (AZO)/n-type oxide semiconductor/p-type Cu2O heterojunction solar cells fabricated using p-type Cu2O sheets prepared by thermally oxidizing Cu sheets. The multicomponent oxide thin film used as the n-type semiconductor layer was prepared with various chemical compositions on non-intentionally heated Cu2O sheets under various deposition conditions using a pulsed laser deposition method. In Cu2O-based heterojunction solar cells fabricated using various ternary compounds as the n-type oxide thin-film layer, the best photovoltaic performance was obtained with an n-ZnGa2O4 thin-film layer. In most of the Cu2O-based heterojunction solar cells using multicomponent oxides composed of combinations of various binary compounds, the obtained photovoltaic properties changed gradually as the chemical composition was varied. However, with the ZnO-MgO and Ga2O3-Al2O3 systems, higher conversion efficiencies (η) as well as a high open circuit voltage (Voc) were obtained by using a relatively small amount of MgO or Al2O3, e.g., (ZnO)0.91-(MgO)0.09 and (Ga2O3)0.975-(Al2O3)0.025, respectively. When Cu2O-based heterojunction solar cells were fabricated using Al2O3-Ga2O3-MgO-ZnO (AGMZO) multicomponent oxide thin films deposited with metal atomic ratios of 10, 60, 10 and 20 at.% for the Al, Ga, Mg and Zn, respectively, a high Voc of 0.98 V and an η of 4.82% were obtained. In addition, an enhanced η and an improved fill factor could be achieved in AZO/n-type multicomponent oxide/p-type Cu2O heterojunction solar cells fabricated using Na-doped Cu2O (Cu2O:Na) sheets that featured a resistivity controlled by optimizing the post-annealing temperature and duration. Consequently, an η of 6.25% and a Voc of 0.84 V were obtained in a MgF2/AZO/n-(Ga2O3-Al2O3)/p-Cu2O:Na heterojunction solar cell fabricated using a Cu2O:Na sheet with a resistivity of approximately 10 Ω·cm and a (Ga0.975Al0

[delta] precipitation in an Al-Li-Cu-Mg-Zr alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, K.S.; Mukhopadhyay, A.K.; Gokhale, A.A.

1994-05-15

AlLi based [delta] phase has an NaTl structure (i.e., a diamond cubic) with a = 0.637nm and is an equilibrium phase in the binary Al-Li system. In heat treated binary Al-Li alloys of appropriate compositions, [delta] phase can format grain boundaries as well as within the grains. In commercially heat treated Al-Li-Cu alloys of 2090 specification, the grain boundary precipitate [delta] of the binary Al-Li system is replaced by a combination of T[sub 2](Al[sub 6]CuLi[sub 3]), R(Al[sub 5]CuLi[sub 3]) and T[sub 1](Al[sub 2]CuLi) phases. In similarly treated Al-Li-Cu-Mg alloys of 8090 specification, the copper rich T[sub 2] phase, present inmore » the form of Al[sub 6]CuLi[sub 3[minus]x]Mg[sub x], is known to be the major coarse g.b. precipitate. The presence of an Al-Li-Cu-Mg based C phase at the grain boundaries of the commercially heat treated 8090 alloys has also been documented. No detailed study has yet been carried out to verify whether the [delta] phase can be present at the grain boundaries of the commercially heat treated 8090 alloys. Given the correlations between the g.b. phase morphology, g.b. phase chemistry, and the stress corrosion cracking resistance of these alloys, it is important that the g.b. precipitates be examined and identified. In this paper results using TEM are presented to show that the [delta] phase can be present in varying amounts at the grain boundaries in an 8090 alloy when heat treated in the temperature range of 170--350 C. An examination is also made of the [delta] precipitation within the grain to establish that the T[sub 2]/[alpha]-Al interface is the dominant nucleation site for the noncoherent [delta] phase.« less

Effect of Hydroxyapatite on the Mechanical Properties and Corrosion Behavior of Mg-Zn-Y Alloy

PubMed Central

Chiu, Chun; Lu, Chih-Te; Chen, Shih-Hsun; Ou, Keng-Liang

2017-01-01

Mg-Zn-Y alloys with a long period stacking ordered (LPSO) phase are potential candidates for biodegradable implants; however, an unfavorable degradation rate has limited their applications. Hydroxyapatite (HA) has been shown to enhance the corrosion resistance of Mg alloys. In this study, Mg97Zn1Y2-0.5 wt% HA composite was synthesized and solution treated at 500 °C for 10 h. The corrosion behavior of the composite was studied by electrochemical and immersion tests, while the mechanical properties were investigated by a tensile test. Addition of HA particles improves the corrosion resistance of Mg97Zn1Y2 alloy without sacrificing tensile strength. The improved corrosion resistance is due to the formation of a compact Ca-P surface layer and a decrease of the volume fraction of the LPSO phase, both resulting from the addition of HA. After solution-treatment, the corrosion resistance of the composite decreases. This is due to the formation of a more extended LPSO phase, which weakens its role as a corrosion barrier in protecting the Mg matrix. PMID:28773216

Effect of Ni addition to the Cu substrate on the interfacial reaction and IMC growth with Sn3.0Ag0.5Cu solder

NASA Astrophysics Data System (ADS)

Zhang, Xudong; Hu, Xiaowu; Jiang, Xiongxin; Li, Yulong

2018-04-01

The formation and growth of intermetallic compound (IMC) layer at the interface between Sn3.0Ag0.5Cu (SAC305) solder and Cu- xNi ( x = 0, 0.5, 1.5, 5, 10 wt%) substrate during reflowing and aging were investigated. The soldering was conducted at 270 °C using reflowing method, following by aging treatment at 150 °C for up to 360 h. The experimental results indicated that the total thickness of IMC increased with increasing aging time. The scallop-like Cu6Sn5 and planar-like Cu3Sn IMC layer were observed between SAC305 solder and purely Cu substrate. As the content of Ni element in Cu substrate was 0.5% or 1.5%, the scallop-like Cu6Sn5 and planar-like Cu3Sn IMC layer were still found between solder and Cu-Ni substrate and the total thickness of IMC layer decreased with the increasing Ni content. Besides, when the Ni content was up to 5%, the long prismatic (Cu,Ni)6Sn5 phase was the only product between solder and substrate and the total thickness of IMC layer increased significantly. Interestingly, the total thickness of IMC decreased slightly as the Ni addition was up to 10%. In the end, the grains of interfacial IMC layer became coarser with aging time increasing while the addition of Ni in Cu substrate could refine IMC grains.

Glucose biosensing using glassy carbon electrode modified with polyhydroxy-C60, glucose oxidase and ionic-liquid.

PubMed

Yang, Tian; Yang, Xiao-Lu; Zhang, Yu-Shuai; Xiao, BaoLin; Hong, Jun

2014-01-01

Direct electrochemistry of glucose oxidase (GOD) was achieved when an ionic liquid/GOD-Polyhydroxy-C60 functional membrane was confined on a glassy carbon electrode (GCE). The cyclic voltammograms (CVs) of the modified GCE showed a pair of redox peaks with a formal potential (E°') of - 329 ± 2 mV. The heterogeneous electron transfer constant (k(s)) was 1.43 s-1. The modified GCE response to glucose was linear in the range from 0.02 to 2.0 mM. The detection limit was 1 μM. The apparent Michaelis-Menten constant (K(m)(app)) was 1.45 mM.

Mechanical Properties of Mg-Gd and Mg-Y Solid Solutions

NASA Astrophysics Data System (ADS)

Kula, Anna; Jia, Xiaohui; Mishra, Raj K.; Niewczas, Marek

2016-12-01

The mechanical properties of Mg-Gd and Mg-Y solid solutions have been studied under uniaxial tension and compression between 4 K and 298 K (-269 °C and 25 °C). The results reveal that Mg-Gd alloys exhibit higher strength and ductility under tension and compression attributed to the more effective solid solution strengthening and grain-boundary strengthening effects. Profuse twinning has been observed under compression, resulting in a material texture with strong dominance of basal component parallel to compression axis. Under tension, twining is less active and the texture evolution is controlled mostly by slip. The alloys exhibit pronounced yield stress asymmetry and significantly different work-hardening behavior under tension and compression. Increasing of Gd and/or Y concentration leads to the reduction of the tension-compression asymmetry due to the weakening of the recrystallization texture and more balanced twinning and slip activity during plastic deformation. The results suggest that under compression of Mg-Y alloys slip is more active than twinning in comparison to Mg-Gd alloys.

A theoretical investigation on Cu/Ag/Au bonding in XH2P⋯MY(X = H, CH3, F, CN, NO2; M = Cu, Ag, Au; Y = F, Cl, Br, I) complexes

NASA Astrophysics Data System (ADS)

Wang, Zhaoxu; Liu, Yi; Zheng, Baishu; Zhou, Fengxiang; Jiao, Yinchun; Liu, Yuan; Ding, XunLei; Lu, Tian

2018-05-01

Intermolecular interaction of XH2P...MY (X = H, CH3, F, CN, NO2; M = Cu, Ag, Au; Y = F, Cl, Br, I) complexes was investigated by means of an ab initio method. The molecular interaction energies are in the order Ag < Cu < Au and increased with the decrease of RP...M. Interaction energies are strengthened when electron-donating substituents X connected to XH2P, while electron-withdrawing substituents produce the opposite effect. The strongest P...M bond was found in CH3H2P...AuF with -70.95 kcal/mol, while the weakest one was found in NO2H2P...AgI with -20.45 kcal/mol. The three-center/four-electron (3c/4e) resonance-type of P:-M-:Y hyperbond was recognized by the natural resonance theory and the natural bond orbital analysis. The competition of P:M-Y ↔ P-M:Y resonance structures mainly arises from hyperconjugation interactions; the bond order of bP-M and bM-Y is in line with the conservation of the idealized relationship bP-M + bM-Y ≈ 1. In all MF-containing complexes, P-M:F resonance accounted for a larger proportion which leads to the covalent characters for partial ionicity of MF. The interaction energies of these Cu/Ag/Au complexes are basically above the characteristic values of the halogen-bond complexes and close to the observed strong hydrogen bonds in ionic hydrogen-bonded species.

Loss of reserves of Cu in liver when Cu supplements are withdrawn from dairy herds in the Waikato region.

PubMed

Hittmann, A R; Grace, N D; Knowles, S O

2012-03-01

To monitor the consequences of withdrawing mineral Cu supplements from two dairy herds with initially high concentrations of Cu in liver. Two herds were selected from dairy farms in the Waikato region of New Zealand that participated in an earlier survey of Cu supplementation practices and Cu status of dairy cows. The herds were fed pasture, grass and maize silage, plus palm kernel expeller (PKE) containing 25-30 mg Cu/kg dry matter (DM) fed at 2-4 kg/cow/day. No mineral Cu supplements were supplied from January 2009. Pasture samples were collected for mineral analysis in September 2008 and April 2009. Concentration of Cu in liver biopsies from the same 9-10 cows per herd was measured on three occasions between April 2009 and May 2010. Pastures on both farms contained 10 mg Cu/kg DM, 0.1-0.5 mg Mo/kg DM and 3.5-4.0 g S/kg DM. The initial herd mean concentrations of Cu in liver were 1,500 (SD 590) and 1,250 (SD 640) μmol Cu/kg fresh tissue. In the absence of mineral Cu supplements, those mean concentrations decreased over 12 months to 705 (SD 370) and 1,120 (SD 560) μmol Cu/kg fresh tissue, respectively. For cows in the first herd, the rate of depletion of liver Cu reserves was influenced by initial concentration of Cu, such that high concentration led to faster loss according to first-order kinetics. Mineral Cu supplementation was not necessary over 12 months for two dairy herds with mean concentrations of Cu in liver >1,250 μmol Cu/kg fresh tissue, grazing pastures containing 10 mg Cu/kg DM and concentrations of Mo <1 mg/kg DM. The quantity and particularly the duration of feeding PKE appeared to be a factor in whether or not the herd lost substantial reserves of Cu in liver during the year. However, the Cu status of both herds in this study was more than adequate to support late pregnancy and mating. CLINICAL REVELANCE: Copper status of the herd should be monitored and on-farm management of Cu nutrition should take into account all sources contributing to

Li-atoms-induced structure changes of Guinier–Preston–Bagaryatsky zones in AlCuLiMg alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, S.Y.; Le, Z.; Chen, Z.K.

2016-11-15

Guinier–Preston–Bagaryatsky (GPB) zones are the well-known strengthening precipitates of AlCuMg alloys formed upon thermal ageing. Here we report that when formed in AlCuLiMg alloys the GPB zones can change significantly in morphology and structure. It is shown that though they do still consist of Al, Cu and Mg elements fundamentally, the GPB zones in AlCuLiMg alloys have a rather different structure due to a featured Li-segregation at their interfaces with the matrix and possible Li-replacement of partial Mg atoms in the structure. As such the Li-containing GPB zones often develop from one-dimensional to quasi-two-dimensional precipitates. - Highlights: • We observemore » Guinier–Preston–Bagaryatsky zone variants in AlCuLiMg alloys. • We obtain atomic-resolution images of the precipitates and model their structures. • Li-atoms play a key role in modifying the structure of these precipitate variants.« less

Zolpidem 10 mg given at daytime is not antagonized by 300 mg caffeine in man.

PubMed

Mattila, M J; Nurminen, M L; Vainio, P; Vanakoski, J

1998-07-01

Caffeine counteracts various effects of traditional benzodiazepines (BZDs). As zolpidem, a short-acting hypnotic, is an atypical GABAA-BZD agonist, we investigated when caffeine would counteract the effects of zolpidem as well. In daytime study I, zolpidem 10 mg (capsule) and caffeine 150 or 300 mg (in decaffeinated coffee) were given, alone and in combinations, to parallel groups (n = 15-17) of healthy students in double-blind and placebo-controlled manner. Objective and subjective tests were done before and 45 min and 90 min after intake. Ranked delta values (changes from baseline) were analysed by one-way contrast ANOVA and Scheffe's tests. In daytime study II, four healthy subjects took zolpidem 10 mg alone, and together with blinded caffeine 250 mg or (at -45 min) erythromycin 750 mg. Objective and subjective effects were measured and plasma zolpidem concentrations assayed at baseline and 45 min and 90 min after zolpidem intake. In study I, practice effects after placebo (ad + 30%) were seen for letter cancellation and digit symbol substitution but not for flicker fusion tests. Zolpidem alone significantly impaired (P < 0.05 vs delta placebo) letter cancellation and digit symbol substitution at 45 min and 90 min, lowered the flicker fusion threshold at 45 min, and caused subjective drowsiness, mental slowness, clumsiness and feeling of poor performance. Caffeine alone showed a non-significant trend to improve objective performance. The combined effects of zolpidem and either dose of caffeine matched those measured after zolpidem alone. Zolpidem + caffeine 300 mg was not stronger than zolpidem + caffeine 150 mg in impairing immediate memory and causing subjective sedation. In study II, zolpidem caused objective and subjective sedation; neither caffeine nor erythromycin modulated the effects of zolpidem or plasma zolpidem concentrations. The sedative effects of 10 mg of zolpidem are not antagonized by 150-300 mg of caffeine in pharmacodynamic or pharmacokinetic

TL-OSL study of Li3PO4: Mg, Cu phosphor

NASA Astrophysics Data System (ADS)

Rahangdale, S. R.; Wankhede, S. P.; Dhabekar, B. S.; Palikundwar, U. A.; Moharil, S. V.

2015-08-01

In the present work, we report the thermoluminescence and optically stimulated luminescence properties of Mg and Cu doped Li3PO4 phosphor. The phosphor was synthesized by precipitation method. The thermoluminescence dosimetric peak temperature for the phosphor varies with concentrations of Mg and Cu. Li3PO4 shows good response to 470nm optical stimulation. The OSL sensitivity of the phosphor is approximately 12 times than that of standard Lithium magnesium phosphate. This study may help to develop this material for the application in real time dosimetry using optically stimulated luminescence.

Influence of calcium on transport properties, band spectrum and superconductivity of YBa2Cu3O(y) and YBa(1.5)La(0.5)Cu3O(y)

NASA Technical Reports Server (NTRS)

Gasumyants, V. E.; Vladimirskaya, E. V.; Patrina, I. B.

1995-01-01

The comparative investigation of transport phenomena in Y(1-x)Ca(x)Ba2Cu3O(y) (0 is less than x is less than 0.25; 6.96 is greater than y is greater than 6.87 and 6.73 is less than x is less than 6.53); Y(1-x)Ca(x)Ba(1.5)La(0.5)Cu3O(y) (0 is less than x is less than 0.5; 7.12 is greater than y is greater than 6.96) and YBa(2-x)La(x)Cu3O(y) (0 is less than x is less than 0.5; 6.95 is less than y is less than 7.21) systems have been carried out. The temperature dependencies of resistivity and thermopower have been measured. It was found that the S(T) dependencies take some additional features with Ca content increase. The results obtained have been analyzed on the basis of the phenomenological theory of electron transport in the case of the narrow conductive band. The main parameters of the band spectrum (the band filling with electrons degree and the total effective band width) have been determined. The dependencies of these from contents of substituting elements are discussed. Analyzing the results obtained simultaneously with the tendencies in oxygen content and critical temperature change we have confirmed the conclusion that the oxygen sublattice disordering has a determinant effect on band structure parameters and superconductive properties of YBa2Cu3O(y). The results obtained suggest that Ca gives rise to some peculiarities in band spectrum of this compound.

Microstructure and Interfacial Shear Strength in W/(Zr55Cu30Al10Ni5)100- x Nb x Composites

NASA Astrophysics Data System (ADS)

Mahmoodan, M.; Gholamipour, R.; Mirdamadi, Sh.; Nategh, S.

2017-11-01

In the present study, (Zr55Cu30Al10Ni5)100- x Nb( x=0,1,2,3) bulk metallic glass matrix/tungsten wire composites were fabricated by a gas pressure infiltration process at temperature 950 °C for 5 min. Microstructural studies and mechanical behaviors of the materials have been investigated by scanning electron microscopy, transmission electron microscopy and pullout tests. The mechanical results showed that the interface shear strength in the composite sample with X = 2 increased more than twice compared to the composite sample with X = 0. Based on the microstructural results, the addition of two atomic percent Nb in the matrix composite causes an increase in the diffusion band thickness during the melt infiltration and change in the interface fracture mode as a result of pullout test.

Critical current density and irreversibility line of CuBa{sub 2}Ca{sub 3}Cu{sub 4}O{sub y}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iyo, A.; Tokumoto, M.; Ihara, H.

The critical current density and irreversibility line of the single-phase polycrystalline sample of CuBa{sub 2}Ca{sub 3}Cu{sub 4}O{sub y} with T{sub c}= 117 K have been estimated from measurements of magnetic hysteresis loops assuming Bean critical state model. Simple power law relations, J{sub c}{proportional_to}H{sup {minus}m}, are observed in the magnetic field dependence of the intragrain J{sub c}. Values of the intragrain J{sub c} in a magnetic field of 1 T are about 10{sup 6} and 10{sup 4} A/cm{sup 2} at temperatures of 5 and 77 K, respectively. An exponential decay of the J{sub c} with increasing temperature, J{sub c}{proportional_to}exp({minus}T/T{sub 0}), ismore » observed below 60 K. The characteristic temperature T{sub 0} of Cu-1234 is T{sub 0}= 16.1 K in a magnetic field of 1.0 T. The dependence of the J{sub c} on temperature is relatively small among the oxide superconductors. Simple power law relations, J{sub c}{proportional_to}(1{minus}T/T{sub c}){sup n}, are found in whole ranges of the temperature and magnetic field. The value of n is 5.24 for a magnetic field of 1.0 T. The irreversibility fields at 70 and 77 K are estimated to be 9.5 and 3.7 T, respectively. The temperature dependence of the H{sub irr} is fitted by H{sub irr}=a(1{minus}T/T{sub c}){sup n} with a=2130 and n=5.91.« less

Phase composition, texture, and anisotropy of the properties of Al-Cu-Li-Mg alloy sheets

NASA Astrophysics Data System (ADS)

Betsofen, S. Ya.; Antipov, V. V.; Serebrennikova, N. Yu.; Dolgova, M. I.; Kabanova, Yu. A.

2017-10-01

The formation of the anisotropy of the mechanical properties, the texture, and the phase composition of thin-sheet Al-4.3Cu-1.4Li-0.4Mg and Al-1.8Li-1.8Cu-0.9 Mg alloys have been studied by X-ray diffraction and tensile tests. Various types of anisotropy of the strength properties of the alloys have been revealed: normal anisotropy (strength in the longitudinal direction is higher than that in the transverse direction) in the Al-4.3Cu-1.4Li-0.4Mg alloy and inverse anisotropy in the Al-1.8Li-1.8Cu-0.9Mg alloy. It is shown that the anisotropy of the strength properties is dependent not only on the texture of a solid solution, but also on the content and the texture of the δ' (Al3Li) and T1 (Al2CuLi) phases and their coherency and compatibility of deformation with the matrix.

Synthesis, structure and electrochemistry of LiMn 2- yCr y/2 Cu y/2 O 4 (0.0⩽ y⩽0.5) prepared by wet chemistry

NASA Astrophysics Data System (ADS)

Julien, C.; Ruth Mangani, I.; Selladurai, S.; Massot, M.

2002-08-01

The LiMn 2O 4 co-doped with copper and chromium forming LiMn 2- yCr y/2 Cu y/2 O 4 spinel phases have been synthesized by wet chemistry technique using an aqueous solution of metal acetates and dicarboxylic acid (succinic acid) as a complexing agent. The structural properties of the synthesized products have been investigated by X-ray powder diffraction, Raman scattering, and Fourier-transform infrared spectroscopy. To improve the rechargeable capacity of Li//LiMn 2- yCr y/2 Cu y/2 O 4 cells, the electrochemical features of LiMn 2- yCr y/2 Cu y/2 O 4 compounds have been evaluated as positive electrode materials. The structural properties of these oxides are very similar to LiMn 2O 4, their electrochemical performances show that the capacity is maintained 95% of the initial value at the 36th cycle for y=0.1, this being explained by the change of Mn 3+/Mn 4+ ratio in doped phases.

Amorphization reaction in thin films of elemental Cu and Y

NASA Astrophysics Data System (ADS)

Johnson, R. W.; Ahn, C. C.; Ratner, E. R.

1989-10-01

Compositionally modulated thin films of Cu and Y were prepared in an ultrahigh-vacuum dc ion-beam deposition chamber. The amorphization reaction was monitored by in situ x-ray-diffraction measurements. Growth of amorphous Cu1-xYx is observed at room temperature with the initial formation of a Cu-rich amorphous phase. Further annealing in the presence of unreacted Y leads to Y enrichment of the amorphous phase. Growth of crystalline CuY is observed for T=469 K. Transmission-electron-microscopy measurements provide real-space imaging of the amorphous interlayer and growth morphology. Models are developed, incorporating metastable interfacial and bulk free-energy diagrams, for the early stage of the amorphization reaction.

Crystallographic and magnetic properties of Cu2U-type hexaferrite

NASA Astrophysics Data System (ADS)

Kamishima, K.; Tajima, R.; Watanabe, K.; Kakizaki, K.; Fujimori, A.; Sakai, M.; Watanabe, K.; Abe, H.

2015-02-01

We have investigated the synthesis conditions, and the magnetic properties of the Cu2U-type hexagonal ferrite, Ba4Cu2Fe36O60. The Cu2U-type hexaferrite was synthesized at the sintering temperature of 1050 °C with the initial composition of Ba4.4Cu2Fe37.6O62.8 (Cu2U+0.2T-block). The saturation magnetizations at 300 K and 5 K are 46.8 A m2/kg and 65.0 A m2/kg, respectively. The Curie temperature is 420 °C which is lower than that of the M-type ferrite (450 °C) but higher than that of the Cu2Y-type ferrite (320 °C). The amount of the nonmagnetic impurity in this sample is estimated to be about 10 wt% by the electron probe micro analysis. We estimated the expected saturation magnetization to be 65.2 A m2/kg, by assuming the model of a Néel-type ferrimagnetic structure and the reduction of magnetization by the 10 wt% nonmagnetic impurity. This is consistent with the observed magnetization of 65.0 A m2/kg at 5 K.

Fretting Fatigue Experiment and Analysis of AlSi9Cu2Mg Alloy

PubMed Central

Wang, Jun; Xu, Hong; Su, Tiexiong; Zhang, Yi; Guo, Zhen; Mao, Huping; Zhang, Yangang

2016-01-01

An investigation was carried out in order to study the fretting fatigue behavior of an AlSi9Cu2Mg aluminum alloy. The fretting fatigue tests of AlSi9Cu2Mg were performed using a specially designed testing machine. The failure mechanism of fretting fatigue was explored by studying the fracture surfaces, fretting scars, fretting debris, and micro-hardness of fretting fatigue specimens using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and micro Vickers hardness test techniques. The experimental results show that the fretting fatigue limit (42 MPa) is significantly reduced to approximately 47% of the plain fatigue limit (89 MPa) under 62.5 MPa contact pressure. Furthermore, the fretting fatigue life decreases with increasing alternating stress and increasing contact pressure. The examination results suggest that the stress concentrates induced by oxidation-assisted wear on the contact interface led to the earlier initiation and propagation of crack under the fretting condition. PMID:28774103

Fretting Fatigue Experiment and Analysis of AlSi9Cu2Mg Alloy.

PubMed

Wang, Jun; Xu, Hong; Su, Tiexiong; Zhang, Yi; Guo, Zhen; Mao, Huping; Zhang, Yangang

2016-12-05

An investigation was carried out in order to study the fretting fatigue behavior of an AlSi9Cu2Mg aluminum alloy. The fretting fatigue tests of AlSi9Cu2Mg were performed using a specially designed testing machine. The failure mechanism of fretting fatigue was explored by studying the fracture surfaces, fretting scars, fretting debris, and micro-hardness of fretting fatigue specimens using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and micro Vickers hardness test techniques. The experimental results show that the fretting fatigue limit (42 MPa) is significantly reduced to approximately 47% of the plain fatigue limit (89 MPa) under 62.5 MPa contact pressure. Furthermore, the fretting fatigue life decreases with increasing alternating stress and increasing contact pressure. The examination results suggest that the stress concentrates induced by oxidation-assisted wear on the contact interface led to the earlier initiation and propagation of crack under the fretting condition.

Full magnetic dispersion relation in the frustrated quasi-1D ferromagnet Ca2Y2Cu5O10

NASA Astrophysics Data System (ADS)

Matsuda, M.; Ma, J.; Garlea, V. O.; Nishimoto, S.; Drechsler, S.-L.; Kuzian, R. O.; Ito, T.; Yamaguchi, H.; Oka, K.

2014-03-01

Ca2Y2Cu5O10 consists of edge-sharing CuO2 chains, in which Cu2+ ions carry spin 1/2. The nearest-neighbor (J1) and the next-nearest-neighbor interaction (J2) are ferromagnetic and antiferromagnetic, respectively. For the J1-J2 model the theory predicts that when the ratio α(= | J2 /J1 |) becomes larger than 0.25, the ground state becomes a spiral state. For the aforementioned compound, Kuzian et al. determined α to be 0.19, which is close to the critical value. However, the parameters were fitted using the observed data up to ~10 meV, above which the magnetic excitations were found to be broadened. In order to determine the overall dispersion relation, we performed inelastic neutron scattering experiments using the HYSPEC neutron spectrometer at the SNS. We succeeded in observing the full magnetic dispersion that extends up to ~55 meV. As previously observed, the magnetic excitations appeared to almost vanish at ~11.5 meV. We also found another noticeable gap-like behavior at ~28 meV. We re-evaluate the essential exchange coupling parameters and discuss the origin of gap-like regions in the spin-wave dispersion.

Size effect model on kinetics of interfacial reaction between Sn-xAg-yCu solders and Cu substrate

PubMed Central

Huang, M. L.; Yang, F.

2014-01-01

The downsizing of solder balls results in larger interfacial intermetallic compound (IMC) grains and less Cu substrate consumption in lead-free soldering on Cu substrates. This size effect on the interfacial reaction is experimentally demonstrated and theoretically analyzed using Sn-3.0Ag-0.5Cu and Sn-3.5Ag solder balls. The interfacial reaction between the Sn-xAg-yCu solders and Cu substrates is a dynamic response to a combination of effects of interfacial IMC growth, Cu substrate consumption and composition variation in the interface zone. A concentration gradient controlled (CGC) kinetics model is proposed to explain the combined effects. The concentration gradient of Cu at the interface, which is a function of solder volume, initial Cu concentration and reaction time, is the root cause of the size effect. We found that a larger Cu concentration gradient results in smaller Cu6Sn5 grains and more consumption of Cu substrate. According to our model, the growth kinetics of interfacial Cu6Sn5 obeys a t1/3 law when the molten solder has approached the solution saturation, and will be slower otherwise due to the interfering dissolution mechanism. The size effect introduced in this model is supported by a good agreement between theoretical and experimental results. Finally, the scope of application of this model is discussed. PMID:25408359

Microstructure, Mechanical Properties, and Age-Hardening Behavior of an Al-Si-Fe-Mn-Cu-Mg Alloy Produced by Spray Deposition

NASA Astrophysics Data System (ADS)

Feng, Wang; Jishan, Zhang; Baiqing, Xiong; Yongan, Zhang

2011-02-01

It has been recognized generally that the spray-deposited process is an innovative technique of rapid solidification. In this paper, Al-20Si-5Fe-3Mn-3Cu-1Mg alloy was synthesized by the spray atomization and deposition technique. The microstructure and mechanical properties of the spray-deposited alloy were studied using x-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and tensile tests. It is observed that the microstructure of spray-deposited Al-20Si-5Fe-3Mn-3Cu-1Mg alloy is composed of the α-Al,Si and the particle-like Al15(FeMn)3Si2 compounds. The aging process of the alloy was investigated by microhardness measurement, differential scanning calorimetry analysis, and TEM observations. The results indicate that the two types of precipitates, S-Al2CuMg and σ-Al5Cu6Mg2 precipitate from matrix and improve the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300 °C).

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

DOE PAGES

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; ...

2016-12-15

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

NASA Astrophysics Data System (ADS)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; Zimmer, Mindy M.; Pollington, Anthony D.; Rector, Kirk D.

2017-01-01

Glassy nuclear fallout debris from near-surface nuclear tests is fundamentally reprocessed earth material. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. This study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test ("trinitite") and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. The volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

Investigation on Hot Workability of Homogenized Al-Zn-Mg-Cu Alloy Based on Activation Energy and Processing Map

NASA Astrophysics Data System (ADS)

Peng, Xiaoyan; Su, Wusen; Xiao, Dan; Xu, Guofu

2018-06-01

Hot deformation behaviors of the homogenized Al-Zn-Mg-Cu alloy were studied by uniaxial compression tests carried out at 623-743 K and strain rates of 0.01-10 s-1. The constitutive equation was developed for the activation energy, and thus the activation energy map was constructed. During the hot deformation, the dominated softening mechanisms were the dynamic recovery and dynamic recrystallization, which were most likely to be driven with increasing temperature and decreasing activation energy. Based on the superposition of the activation energy map and the processing map, together with the microstructure characteristics, the optimized hot workability of the alloy was proposed at the domain (670-743 K and 0.01-0.16 s-1), where the peak efficiency was 0.39 and the activation energy range was 196-260 kJ mol-1.

Electron backscatter diffraction analysis of gold nanoparticles on Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bochmann, A.; Teichert, S., E-mail: steffen.teichert@fh-jena.de; Katzer, C.

2015-06-07

It has been shown recently that the incorporation of gold nanoparticles into Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ} enhances the superconducting properties of this material in a significant way. Previous XRD and TEM investigations suggest different crystallographic relations of the gold nanoparticles with respect to the epitaxial Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ}. Here, detailed investigations of the crystal orientations for a large ensemble of gold nanoparticles with electron backscatter diffraction are reported. The average size of the gold nanoparticles is in the range of 60 nm–80 nm. We identified five different types of heteroepitaxial relationships between the gold nanoparticles and the superconductor film,more » resulting in complex pole figures. The observed different types of crystallographic orientations are discussed based on good lattice matching and the formation of low energy interfaces.« less

Trap-assisted large gain in Cu{sub 2}O/C{sub 60} hybrid ultraviolet/visible photodetectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Lan; Xi, Qiaoyue; Gao, Ge

2016-04-18

Photomultiplication-type ultraviolet (UV)/visible photodetectors (PDs) are demonstrated in an electrodeposited Cu{sub 2}O/C{sub 60} hybrid structure. These simple organic/inorganic hybrid PDs exhibit external quantum efficiencies (EQEs) of 1.1 × 10{sup 4}% under illumination of 365 nm UV light at −3 V, indicating a large gain of photocurrent for these devices. Such an EQE is one of the highest values among the reported organic/inorganic hybrid PDs at the same voltage. Cu{sub 2}O and C{sub 60} are found to play different roles in realizing the photomultiplication. Copper vacancies are proposed as the defects in the electrodeposited Cu{sub 2}O layers, which can trap photogenerated holes. Such trapped holesmore » will trigger the injection of multiple electrons and hence result in the photocurrent gain of the devices while C{sub 60} primarily acts as a light absorption media to provide free holes.« less

Magnesium effects on CdSe self-assembled quantum dot formation on Zn xCd yMg 1-x-ySe layers

NASA Astrophysics Data System (ADS)

Noemi Perez-Paz, M.; Lu, Hong; Shen, Aidong; Jean Mary, F.; Akins, Daniel; Tamargo, Maria C.

2006-09-01

Optical and morphological studies are used to investigate the effects of chemical composition and, in particular, the magnesium content of the Zn xCd yMg 1-x-ySe barrier layers on the size, density and uniformity of CdSe self-assembled quantum dots (QDs). A reduction of the uncapped QD size, as well as a blue shift of the capped QD photoluminescence peak position by increasing Mg concentration in the Zn xCd yMg 1-x-ySe barrier has been demonstrated by changing the Mg cell temperature during growth. In addition, a more uniform and more densely packed QD layer has been observed with an increase of the MgSe fraction in the Zn xCd yMg 1-x-ySe barrier layer using three-dimensional topographic atomic force microscopy images of the surface of uncapped QDs. Results point to Mg as a chemical factor that induces QD formation, either by increasing the density of atomic steps or/and by changing the energy of the Zn xCd yMg 1-x-ySe surface.

A novel nonenzymatic amperometric hydrogen peroxide sensor based on CuO@Cu2O nanowires embedded into poly(vinyl alcohol).

PubMed

Chirizzi, Daniela; Guascito, Maria Rachele; Filippo, Emanuela; Tepore, Antonio

2016-01-15

A new, very simple, rapid and inexpensive nonenzymatic amperometric sensor for hydrogen peroxide (H2O2) detection is proposed. It is based on the immobilization of cupric/cuprous oxide core shell nanowires (CuO@Cu2O-NWs) in a poly(vinyl alcohol) (PVA) matrix directly drop casted on a glassy carbon electrode surface to make a CuO@Cu2O core shell like NWs PVA embedded (CuO@Cu2O-NWs/PVA) sensor. CuO nanowires with mean diameters of 120-170nm and length in the range 2-5μm were grown by a simple catalyst-free thermal oxidation process based on resistive heating of pure copper wires at ambient conditions. The oxidation process of the copper wire surface led to the formation of a three layered structure: a thick Cu2O bottom layer, a CuO thin intermediate layer and CuO nanowires. CuO nanowires were carefully scratched from Cu2O layer with a sharp knife, dispersed into ethanol and sonicated. Then, the NWs were embedded in PVA matrix. The morphological and spectroscopic characterization of synthesized CuO-NWs and CuO@Cu2O-NWs/PVA were performed by transmission electron microscopy (TEM), selected area diffraction pattern (SAD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. Moreover a complete electrochemical characterization of these new CuO@Cu2O-NWs/PVA modified glassy carbon electrodes was performed by Cyclic Voltammetry (CV) and Cronoamperometry (CA) in phosphate buffer (pH=7; I=0.2) to investigate the sensing properties of this material against H2O2. The electrochemical performances of proposed sensors as high sensitivity, fast response, reproducibility and selectivity make them suitable for the quantitative determination of hydrogen peroxide substrate in batch analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Growth of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4-yZn yO 12-δ superconductor with optimum carriers

NASA Astrophysics Data System (ADS)

Mumtaz, M.; Khan, Nawazish A.; Khan, E. U.

2010-05-01

We have tried to vary the carriers concentration in Cu 0.5Tl 0.5Ba 2Ca 3Cu 4-yZn yO 12-δ ( y = 0, 1, 1.5, 2, 2.5) superconductor with the help of post-annealing experiments carried out in nitrogen, oxygen and air and to investigate its effects on the superconductivity parameters. The zero resistivity critical temperature [ T c( R = 0)], the magnitude of diamagnetism and critical current [ I c( H = 0)] are found to increase in Zn free samples after post-annealing in oxygen and air, while these superconducting properties have been suppressed after post-annealing in nitrogen at 550 °C for 6 h. The post-annealing of Zn-doped samples in air has marginally increased the superconducting properties, while these properties have been suppressed after post-annealing in nitrogen and oxygen. These studies have led us to the definite conclusion that the Zn-doped material has grown with optimum carriers concentration.

Influence of Sc on microstructure and mechanical properties of Al-Si-Mg-Cu-Zr alloy

NASA Astrophysics Data System (ADS)

Li, Yukun; Du, Xiaodong; Zhang, Ya; Zhang, Zhen; Fu, Junwei; Zhou, Shi'ang; Wu, Yucheng

2018-02-01

In the present study, the effects of Mg, Cu, Sc and Zr combined additions on the microstructure and mechanical properties of hypoeutectic Al-Si cast alloy were systematically investigated. Characterization techniques such as optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electron back-scatter diffraction (EBSD), atomic force microscopy (AFM), transmission electron microscope (TEM), Brinell hardness tester and universal testing machine were employed to analyze the microstructure and mechanical properties. The results showed that Sc served as modifier on the microstructure of Al-3Si-0.45Mg-0.45Cu-0.2Zr alloys, including modification of eutectic Si and grains. Extraordinarily, grain refinement was found to be related to the primary particles, which exhibited a close orientation to matrix. After T6 heat treatment, the grain structures were composed of nano-scaled secondary Al3(Sc, Zr) precipitates and spherical eutectic Si. Combined with T6 heat treatment, the highest hardness, yield strength, ultimate tensile strength and elongation were achieved in 0.56 wt.% Sc-modified alloy. Interestingly, the strength and ductility had a similar tendency. This paper demonstrated that combined additions of Mg, Cu, Sc and Zr could significantly improve the microstructure and performance of the hypoeutectic Al-Si cast alloy.

Wear behavioral study of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load

NASA Astrophysics Data System (ADS)

Harlapur, M. D.; Sondur, D. G.; Akkimardi, V. G.; Mallapur, D. G.

2018-04-01

In the current study, the wear behavior of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy has been investigated. Microstructure, SEM and EDS results confirm the presence of different intermetallic and their effects on wear properties of Al25Mg2Si2Cu4Ni alloy in as cast as well as aged condition. Alloying main elements like Si, Cu, Mg and Ni partly dissolve in the primary α-Al matrix and to some amount present in the form of intermetallic phases. SEM structure of as cast alloy shows blocks of Mg2Si which is at random distributed in the aluminium matrix. Precipitates of Al2Cu in the form of Chinese script are also observed. Also `Q' phase (Al-Si-Cu-Mg) be distributed uniformly into the aluminium matrix. Few coarsened platelets of Ni are seen. In case of 7 hr homogenized samples blocks of Mg2Si get rounded at the corners, Platelets of Ni get fragmented and distributed uniformly in the aluminium matrix. Results show improved volumetric wear resistance and reduced coefficient of friction after homogenizing heat treatment.

Properties of Sn3.8Ag0.7Cu Solder Alloy with Trace Rare Earth Element Y Additions

NASA Astrophysics Data System (ADS)

Hao, H.; Tian, J.; Shi, Y. W.; Lei, Y. P.; Xia, Z. D.

2007-07-01

In the current research, trace rare earth (RE) element Y was incorporated into a promising lead-free solder, Sn3.8Ag0.7Cu, in an effort to improve the comprehensive properties of Sn3.8Ag0.7Cu solder. The range of Y content in Sn3.8Ag0.7Cu solder alloys varied from 0 wt.% to 1.0 wt.%. As an illustration of the advantage of Y doping, the melting temperature, wettability, mechanical properties, and microstructures of Sn3.8Ag0.7CuY solder were studied. Trace Y additions had little influence on the melting behavior, but the solder showed better wettability and mechanical properties, as well as finer microstructures, than found in Y-free Sn3.8Ag0.7Cu solder. The Sn3.8Ag0.7Cu0.15Y solder alloy exhibited the best comprehensive properties compared to other solders with different Y content. Furthermore, interfacial and microstructural studies were conducted on Sn3.8Ag0.7Cu0.15Y solder alloys, and notable changes in microstructure were found compared to the Y-free alloy. The thickness of an intermetallic compound layer (IML) was decreased during soldering, and the growth of the IML was suppressed during aging. At the same time, the growth of intermetallic compounds (IMCs) inside the solder was reduced. In particular, some bigger IMC plates were replaced by fine, granular IMCs.

41 CFR 60-30.16 - Appearances.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Appearances. 60-30.16 Section 60-30.16 Public Contracts and Property Management Other Provisions Relating to Public Contracts... 11246 Hearings and Related Matters § 60-30.16 Appearances. (a) Representation. The parties or other...

41 CFR 60-30.16 - Appearances.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Appearances. 60-30.16 Section 60-30.16 Public Contracts and Property Management Other Provisions Relating to Public Contracts... 11246 Hearings and Related Matters § 60-30.16 Appearances. (a) Representation. The parties or other...

Reduced anti-ferromagnetism promoted by Zn 3d 10 substitution at CuO 2 planar sites of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4O 12-δ superconductors

NASA Astrophysics Data System (ADS)

Mumtaz, M.; Khan, Nawazish A.

2009-11-01

The role of charge carriers in ZnO 2/CuO 2 planes of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4-yZn yO 12-δ material in bringing about superconductivity has been explained. Due to suppression of anti-ferromagnetic order with Zn 3d 10 ( S=0) substitution at Cu 3d 9(S={1}/{2}) sites in the inner CuO 2 planes of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4O 12-δ superconductor, the distribution of charge carriers becomes homogeneous and optimum, which is evident from the enhanced superconductivity parameters. The decreased c-axis length with the increase of Zn doping improves interlayer coupling and hence the three dimensional (3D) conductivity in the unit cell is enhanced. Also the softening of phonon modes with the increased Zn doping indicates that the electron-phonon interaction has an essential role in the mechanism of high- Tc superconductivity in these compounds.

41 CFR 60-30.33 - Discovery.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Discovery. 60-30.33... 11246 Expedited Hearing Procedures § 60-30.33 Discovery. (a) Any party may serve requests for admissions... with § 60-30.8, the Administrative Law Judge may allow the taking of depositions. Other discovery will...

41 CFR 60-30.33 - Discovery.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Discovery. 60-30.33... 11246 Expedited Hearing Procedures § 60-30.33 Discovery. (a) Any party may serve requests for admissions... with § 60-30.8, the Administrative Law Judge may allow the taking of depositions. Other discovery will...

41 CFR 60-30.33 - Discovery.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Discovery. 60-30.33... 11246 Expedited Hearing Procedures § 60-30.33 Discovery. (a) Any party may serve requests for admissions... with § 60-30.8, the Administrative Law Judge may allow the taking of depositions. Other discovery will...

41 CFR 60-30.33 - Discovery.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Discovery. 60-30.33... 11246 Expedited Hearing Procedures § 60-30.33 Discovery. (a) Any party may serve requests for admissions... with § 60-30.8, the Administrative Law Judge may allow the taking of depositions. Other discovery will...

41 CFR 60-30.33 - Discovery.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Discovery. 60-30.33... 11246 Expedited Hearing Procedures § 60-30.33 Discovery. (a) Any party may serve requests for admissions... with § 60-30.8, the Administrative Law Judge may allow the taking of depositions. Other discovery will...

Spin Polarization of Mg-23 in Mg-24 + Au, Cu and Al Collisions at 91 A MeV

NASA Technical Reports Server (NTRS)

Matsuta, K.; Fukuda, S.; Izumikawa, T.; Tanigaki, M.; Fukuda, M.; Nakazato, M.; Mihara, M.; Onishi, T.; Yamaguchi, T.; Miyake, T.

1994-01-01

Spin polarization of beta-emitting fragment Mg-23(I(sup pi) = 3/2(sup +), T(sub 1/2 = l1.3 s) produced through the projectile fragmentation process in Mg-24 + Au, Cu and Al collisions has been observed at 91 AMeV. General trend in the observed momentum dependence of polarization is reproduced well qualitatively by a simple fragmentation model based on the participant-spectator picture, for heavy and light targets. However the polarization behavior differs from this model in tern of zero crossing momentum, which become prominent in the case of Cu target, where the polarization is not monotone function of the fragment momentum.

Structural and magnetic characterization of the complete delafossite solid solution (CuAlO2)1-x(CuCrO2)x

NASA Astrophysics Data System (ADS)

Barton, Phillip; Seshadri, Ram; Knöller, Andrea; Rosseinsky, Matthew

2012-02-01

We have prepared the complete delafossite solid solution between diamagnetic CuAlO2 and the t2g^3 frustrated antiferromagnet CuCrO2. The crystal structure and magnetism were studied with powder x-ray diffraction and magnetometry. The unit cell parameters follow the V'egard law and μeff is equal to the Cr^3+ spin-only S = 3/2 value. θCW is negative and its magnitude increases with Cr substitution. For dilute Cr compositions, JBB was estimated by mean-field theory to be 3.0,eV. Despite the sizable θCW, long-range antiferromagnetic order does not develop until x is almost 1, and is preceeded by glassy behavior. For all samples, the 5,isothermal magnetization is sub-Brillouin and does not saturate in fields up to 5,. A scaled inverse susceptibility plot reveals that significant short-range antiferromagnetic interactions occur in CuCrO2 above its N'eel temperature. Additionally, the Al-substituted samples exhibit uncompensated short-range behavior and x = 0.75 shows glassy characteristics. It is suggested that reduction in magnetic frustration due to the presence of non-magnetic Al does not have as dominant an effect on magnetism as do chemical disorder and dilution of magnetic exchange.

IR and TPD studies of the interaction of alkenes with Cu + sites in CuNaY and CuNaX zeolites of various Cu content. The heterogeneity of Cu + sites

NASA Astrophysics Data System (ADS)

Datka, J.; Kukulska-Zajaç, E.; Kozyra, P.

2006-08-01

Cu + ions in zeolites activate organic molecules containing π electrons by π back donation, which results in a distinct weakening of multiple bonds. In this study, we followed the activation of alkenes (ethene and propene) by Cu + ions in CuY and CuX zeolites of various Cu content. We also studied the strength of bonding of alkenes to Cu + ions. IR studies have shown that there are two kinds of Cu + sites of various electron donor properties. We suppose that they could be attributed to the presence of Cu + ions of various number of oxygen atoms surrounding the cation. IR studies have shown that Cu ions introduced into Y and X zeolites in the first-order (at low Cu content) form Cu + ions of stronger electron donor properties (i.e. activate alkenes to larger extend) than Cu ions introduced in the next order (at higher Cu content). IR and TPD studies of alkenes desorption evidenced that Cu + ions of stronger electron donor properties bond alkenes stronger than less electron donor ones. It suggests that π back donation has more important contribution to the strength of bonding alkenes to cation than π donation.

Study on effects of powder and flake chemistry and morphology on the properties of Al-Cu-Mg-X-X-X powder metallurgy advanced aluminum alloys

NASA Technical Reports Server (NTRS)

Meschter, P. J.; Lederich, R. J.; Oneal, J. E.

1986-01-01

A study was conducted: (1) to develop rapid solidification processed (RSP) dispersoid-containing Al-3Cu-2Li-1Mg-0.2Zr alloys as substitutes for titanium alloys and commercial 2XXX aluminum alloys for service to at least 150 C; and (2) to develop RSP Al-4Li-Cu-Mg-Zr alloys as substitutes for high-strength commercial 7XXX alloys in ambient-temperature applications. RSP Al-3Cu-2Li-1Mg-0.2Zr alloys have density-normalized yield stresses at 150 C up to 52% larger than that of 2124-T851 and up to 30% larger than that of Ti-6Al-4V. Strength at 150 C in these alloys is provided by thermally stable delta' (Al3Li), T1 (Al2LiCu), and S' (Al2CuMg) precipitates. Density-normalized yield stresses of RSP Al-3Cu-2Li-1Mg-0.2Zr alloys are up to 100% larger than that of 2124-T851 and equivalent to that of Al-8Fe-4Ce at 260 C. Strength in the RSP alloys at 260 C is provided by incoherent dispersoids and subboundary constituent particles such as T1 and S. The RSP alloys are attractive substitutes in less than or = 100-h exposures for 2xxx and Al-4Fe-Ce alloys up to 260 C and for titanium alloys up to 150 C. RSP Al-4Li-Cu-Mg-Zr alloys have ambient-temperature yield and ultimate tensile stresses similar to that of 7050-T7651, and are 14% less dense. RSP Al-4Li-0.5Cu-1.5Mg-0.2Zr has a 20% higher specific yield stress, 40% higher specific elastic modulus, and superior corrosion resistance compared to the properties of 7050-T7651. Strength in the Al-4Li-Cu-Mg-Zr alloy class is primarily provided by the substructure and delta' precipitates and is independent of Cu:Mg ratio. Improvements in fracture toughness and transverse-orientation properties in both alloy classes depend on improved melt practices to eliminate oxide inclusions which are incorporated into the consolidated forms.

Effect of Intermetallic on Electromigration and Atomic Diffusion in Cu/SnAg3.0Cu0.5/Cu Joints: Experimental and First-Principles Study

NASA Astrophysics Data System (ADS)

Zhou, Wei; Liu, Lijuan; Li, Baoling; Wu, Ping

2009-06-01

Electromigration phenomena in a one-dimensional Cu/SnAg3.0Cu0.5/Cu joint were investigated with current stressing. The special effect of intermetallic compound (IMC) layers on the formation of serious electromigration damage induced by nonuniform current density distribution was discussed based on experimental results. Meanwhile, hillocks were observed both at the anode and near the cathode of the joint, and they were described as the result of diffusion of atoms and compressive stress released along grain boundaries to the relatively free surface. Moreover, the diffusion behavior of Cu at the cathode was analyzed with the electromigration equation, and the stability of Ag atoms in the solder during electromigration was evaluated with a first-principles method.

Investigation of magnetic properties of superconductors Y0.98 - x Cax Co0.02 Ba2 Cu3O7 - δ

NASA Astrophysics Data System (ADS)

Pourasad, Sepideh; Shakeripour, Hamideh; Hosseini, SeyedSajad; Salamati, Hadi

2018-06-01

The effect of Co2+, 3+ and Ca2+ substitution in Y3+ site in YBa2Cu3O7-δ superconductor has been studied. The series of high temperature superconducting samples of Y1-y-xCoyCaxBa2Cu3O7-δ with 0 ≤ x ≤ 0.015 and y = 0.020 were prepared by solid-state reaction method. The samples were characterized for phase purity and lattice parameter variations by X-ray diffraction. The AC susceptibility curves, χ'(T), show that in reserving cobalt fixed sample with the optimum Tc, by substitution of divalent Ca2+ at the trivalent Y3+ site no sensitive increasing happen in the superconducting transition temperature.

Assessment of retrogression and re-aging treatment on microstructural and mechanical properties of Al-Zn-Mg-Cu P/M alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naeem, Haider T.; College of Engineering, Al-Muthanna University, South Baghdad; Mohammad, Kahtan S.

2015-05-15

In order to understand the importance of the retrogression and re-aging as a heat treatment for improving microstructural and mechanical properties of the Al-Zn-Mg-Cu powder metallurgy alloys, Al-Zn-Mg-Cu-Fe-Cr alloys were fabricated from the elemental powders. Green compacts are compressed under compaction pressure about 370 MPa. The sintering process carried out for the samples of aluminum alloys at temperature was 650°C under argon atmosphere for two hours. The sintered compacts were subjected into homogenizing condition at 470°C for 1.5 hours and then aged at 120°C for 24 hours (T6 temper) after that it carried out the retrogressed at 180°C for 30more » min., and then re-aged at 120°C for 24 hours (RRA). Observations microstructures were examined using optical, scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction. Density and porosity content was conducted for the samples of alloys. The result showing that the highest Vickers hardness exhibited for an Al-Zn-Mg-Cu alloy after underwent the retrogression and reaging treatment. Increasing in hardness was because of the precipitation hardening through precipitate the (Mg Zn) and (Mg{sub 2}Zn{sub 11}) phases during matrix of aluminum-alloy.« less

Superconductor-to-insulator transition and transport properties of underdoped YBa2Cu3O(y) crystals.

PubMed

Semba, K; Matsuda, A

2001-01-15

The carrier-concentration-driven superconductor-to-insulator (SI) transition as well as transport properties in underdoped YBa2Cu3O(y) twinned crystals is studied. The SI transition takes place at y approximately 6.3, carrier concentration n(SI)H approximately 3x10(20) cm(-3), anisotropy rho(c)/rho(ab) approximately 10(3), and the threshold resistivity rho(SI)ab approximately 0.8 mOmega cm which corresponds to a critical sheet resistance h/4e2 approximately 6.5 kOmega per CuO2 bilayer. The evolution of a carrier, nH infiniti y - 6.2, is clearly observed in the underdoped region. The resistivity and Hall coefficient abruptly acquire strong temperature dependence at y approximately 6.5 indicating a radical change in the electronic state.

Glassy and Metastable Crystalline BaTi2O5 by Containerless Processing

NASA Astrophysics Data System (ADS)

Yoda, Shinichi; Kentei Yu, Yu; Kumar, Vijaya; Kameko, Masashi

Many efforts have been devoted to forming bulk glass from the melt of ferroelectric crystalline materials without adding any network-forming oxides such as SiO2 due to the potential for producing transparent glass ceramics with high dielectric constant and enhanced piezoelectric, pyroelectric and electro-optic use. The containerless processing is an attractive synthesis tech-nique as it can prevent melt contamination, minimize heterogeneous nucleation, and allow melt to achieve deep undercooling for forming metastable and glassy materials. We have fabricated a new ferroelectric materiel BaTi2 O5 [1] as bulk glass from melt by us-ing containerless processing and studied the phase relationship between microstructure and ferroelectric properties of BaTi2 O5 [2]. The structures of glassy and metastable crystalline BaTi2 O5 fabricated by the containerless pro-cessing were comprehensively investigated by combined X-ray and neutron diffractions, XANES analyses and computer simulations [3]. The 3-dimensional atomic structure of glassy BaTi2 O5 (g-BaTi2 O5 ), simulated by Reverse Monte Carlo (RMC) modelling on diffraction data, shows that extremely distorted TiO5 polyhedra interconnected with both corner-and edge-shared oxy-gen, formed a higher packing density structure than that of conventional silicate glass linked with only corner-sharing of SiO4 polyhedra. In addition, XANES measurement reveales that five-coordinated TiO5 polyhedra were formable in the crystallized metastable a-and b-BaTi2 O5 phases. The structure of metastable b-BaTi2 O5 was solved by ab initio calculation, and refined by Rietveld refinement as group Pnma with unit lattices a = 10.23784 ˚, b = 3.92715 ˚, c A A = 10.92757 A ˚. Our results show that the glass-forming ability enhanced by containerless pro-cessing, not by `strong glass former', fabricated new bulk oxide glasses with peculiar structures and properties. The intermediate-range structure of g-BaTi2 O5 and the crystalline structure of

Synthesis and structural characterization of transition metal doped MgO: Mg0.95Mn0.01TM0.04O (TM = Co, Ni, Cu)

NASA Astrophysics Data System (ADS)

Islam, Ishtihadah; Khandy, Shakeel Ahmad; Hafiz, Aurangzeb Khurram

2018-05-01

In the present work, preparation and characterization of transition metal doped MgO: Zn0.94Mn0.01TM0.05O (TM = Co, Ni and Cu) nano-particles have been reported. Transition metal doped samples of MgO were synthesized by Sol gel auto combustion method. Structural characterisation from XRD and SEM show the formation of single-phase primary particles, nearly of spherical shaped nano-crystallites. The crystallite size was found to be 78.2, 67.02, 78.11 and 64 nm for pure, Co, Cu and Ni doped MgMnO nano-particles, respectively. Hence, the average crystallite size increases monotonously from Co to Cu doping.

Mechanical Properties and Tensile Failure Analysis of Novel Bio-absorbable Mg-Zn-Cu and Mg-Zn-Se Alloys for Endovascular Applications

PubMed Central

Persaud-Sharma, Dharam; Budiansky, Noah; McGoron, Anthony J.

2013-01-01

In this paper, the mechanical properties and tensile failure mechanism of two novel bio-absorbable as-cast Mg-Zn-Se and Mg-Zn-Cu alloys for endovascular medical applications are characterized. Alloys were manufactured using an ARC melting process and tested as-cast with compositions of Mg-Zn-Se and Mg-Zn-Cu, being 98/1/1 wt.% respectively. Nanoindentation testing conducted at room temperature was used to characterize the elastic modulus (E) and surface hardness (H) for both the bare alloys and the air formed oxide layer. As compared to currently available shape memory alloys and degradable as-cast alloys, these experimental alloys possess superior as-cast mechanical properties that can increase their biocompatibility, degradation kinetics, and the potential for medical device creation. PMID:23543822

Fabrication of 10 μm-scale conductive Cu patterns by selective laser sintering of Cu complex ink

NASA Astrophysics Data System (ADS)

Min, Hyungsuk; Lee, Byoungyoon; Jeong, Sooncheol; Lee, Myeongkyu

2017-02-01

A Cu complex ink was synthesized using copper formate as a precursor and its potential for laser patterning was investigated. The Cu ink was spin-coated onto a substrate and the coated film was space-selectively sintered using a nanosecond-pulsed ultraviolet laser. The unexposed Cu ink could be removed from the film by rinsing it with the dispersing agent used to synthesize the ink, disclosing a conductive Cu pattern. A minimum resistivity of 8.46×10-5 Ω cm was obtained for the Cu lines with 10-20 μm widths. The feasibility of this method for metallization was demonstrated by fabricating a complex Cu electric circuit on an indium tin oxide-coated glass substrate. The selective laser sintering approach provides a simple, cost-effective alternative to conventional lithography for the production of electrode or metallization patterns.

High resolution electron microscopy study of a high Cu variant of Weldalite (tm) 049 and a high strength Al-Cu-Ag-Mg-Zr alloy

NASA Technical Reports Server (NTRS)

Herring, R. A.; Gayle, Frank W.; Pickens, Joseph R.

1991-01-01

Weldalite (trademark) 049 is an Al-Cu-Li-Ag-Mg alloy that is strengthened in artificially aged tempers primarily by very thin plate-like precipitates lying on the set of (111) matrix planes. This precipitate might be expected to be the T(sub 1) phase, Al2CuLi, which has been observed in Al-Cu-Li alloys. However, in several ways this precipitate is similar to the omega phase which also appears as the set of (111) planes plates and is found in Al-Cu-Ag-Mg alloys. The study was undertaken to identify the set of (111) planes precipitate or precipitates in Weldalite (trademark) 049 in the T8 (stretched and artificially aged) temper, and to determine whether T(sub 1), omega, or some other phase is primarily responsible for the high strength (i.e., 700 MPa tensile strength) in this Al-Cu-Li-Ag-Mg alloy.

Investigation the electroplating behavior of self formed CuMn barrier.

PubMed

Wu, Chia-Yang; Lee, Wen-Hsi; Chang, Shih-Chieh; Wang, Ying-Lang

2013-08-01

The electrical and material properties of Copper (Cu) mixed with [0-10 atomic% manganese (Mn)] and pure Cu films deposited on silicon oxide (SiO2)/silicon (Si) are explored. Cu electroplating on self formed CuMn barrier was investigated with different Mn content. The electrochemical deposition of the Cu thin film onto the electrode using CuMn barrier was investigated. Scanning electron microscopic (SEM) micrographs of copper electroplating on CuMn films were examined, and the copper nucleation behaviors changed with the Mn content. Since the electrochemical impedance spectroscopy (EIS) is widely recognized as a powerful tool for the investigation of electrochemical behaviors, the tool was also used to verify the phenomena during plating. It was found that the charge-trasfer impedance decrease with the rise in the Mn content below 5%, but increase with the rise in the Mn content higher than 5%. The result was corresponded to the surface energy, the surface morphology, the corrosion and the oxidation of the substrate.

Effects of Oxygen Deficiency and Dopping of pr in Gd1-x Prx Ba2Cu3O7-y

NASA Astrophysics Data System (ADS)

Zolfagharkhani, G.; Daadmehr, V.; Farzaneh, M.; Sedighiani, A.; Akhavan, M.

2000-09-01

Single phase crystalline samples of Gd1-x Prx Ba2Cu3O7-y with 0.0 ≤ x ≤ 0.2 have been prepared by standard solid state reaction technique and characterized by SEM and XRD. The electrical measurements show two plateaus in Tc versus y curve for GdBa2Cu3O7-y (0<y<0.5), (90K and 60K phases). Metal-insulator transition is seen with increasing Pr concentration and oxygen deficiency. In deoxygenation process of Pr dopant samples, the plateaus come down to lower temperatures and the first plateau becomes smaller than undoped samples. Simultaneous doping of Pr and oxygen deficiency are superimposed on increasing of ρ before transition and suppression of Tc by decreasing of hole concentration in CuO2 planes. The experiments indicate that in GdPr-123 samples, presence of Pr causes the oxygen bond to become stronger than in undoped samples.

Auto-combustion synthesis and characterization of Mg doped CuAlO2 nanoparticles

NASA Astrophysics Data System (ADS)

Agrawal, Shraddha; Parveen, Azra; Naqvi, A. H.

2015-06-01

The synthesis of pure and Mg doped Copper aluminumoxide CuAlO2nanoparticles, a promising p-type TCO (transparent conducting oxide) have been done bysol gel auto combustion method using NaOH as a fuel, calcinated at 600°C. The structural properties were examined by XRD and SEM techniques. The optical absorption spectra of CuAlO2 sample recorded by UV-VIS spectrophotometer in the range of 200 to 800 nm have been presented. The crystallite size was determined by powder X-ray diffraction technique. The electrical behavior of pure and Mg doped CuAlO2 has been studied over a wide range of frequencies by using complex impedance spectroscopy.The variation of a.c. conductivity has been studied as function of frequency and temperature. The data taken together conclude that doping causes decreases in the ac conductivity of the nanoparticles as compared with the pure nanoparticles. Mg doping affects the optical properties and band gap.

Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Jiandi

Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature.more » However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al{sub 8}Cu{sub 4}Ce phase, Al{sub 6}Cu{sub 6}La phase and Al{sub 6}(Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.« less

Non-conventional photocathodes based on Cu thin films deposited on Y substrate by sputtering

NASA Astrophysics Data System (ADS)

Perrone, A.; D'Elia, M.; Gontad, F.; Di Giulio, M.; Maruccio, G.; Cola, A.; Stankova, N. E.; Kovacheva, D. G.; Broitman, E.

2014-07-01

Copper (Cu) thin films were deposited on yttrium (Y) substrate by sputtering. During the deposition, a small central area of the Y substrate was shielded to avoid the film deposition and was successively used to study its photoemissive properties. This configuration has two advantages: the cathode presents (i) the quantum efficiency and the work function of Y and (ii) high electrical compatibility when inserted into the conventional radio-frequency gun built with Cu bulk. The photocathode was investigated by scanning electron microscopy to determine surface morphology. X-ray diffraction and atomic force microscopy studies were performed to compare the structure and surface properties of the deposited film. The measured electrical resistivity value of the Cu film was similar to that of high purity Cu bulk. Film to substrate adhesion was also evaluated using the Daimler-Benz Rockwell-C adhesion test method. Finally, the photoelectron performance in terms of quantum efficiency was obtained in a high vacuum photodiode cell before and after laser cleaning procedures. A comparison with the results obtained with a twin sample prepared by pulsed laser deposition is presented and discussed.

Kinetically inert Cu in coastal waters.

PubMed

Kogut, Megan B; Voelker, Bettina M

2003-02-01

Many studies have shown that Cu and other metals in natural waters are mostly bound by unidentified compounds interpreted to be strong ligands reversibly complexing a given metal. However, commonly applied analytical techniques are not capable of distinguishing strongly but reversibly complexed metal from metal bound in kinetically inert compounds. In this work, we use a modified competitive ligand exchange adsorptive cathodic stripping voltammetry method combined with size fractionation to show that most if not all of the apparently very strongly (log K > or = 13) bound Cu in samples from five New England coastal waters (1-18 nM, 10-60% of total Cu) is actually present as kinetically inert compounds. In three of the five samples examined by ultrafiltration, a significant portion of the 0.2-microm-filtrable inert Cu was retained by a 0.02-microm-pore size filter, suggesting that at least some of the Cu was kinetically inert because it was physically sequestered in colloidal material. The rest of the ambient Cu, and Cu added in titrations, were reversibly bound in complexes that could be modeled as having conditional stability constants of 10(10)-10(13). The Cu-binding ability of these complexes was equivalent to that of seawater containing reasonable concentrations of humic substances from terrestrial sources, approximately 0.15-0.45 mg of C/L. Both the inert compounds and the reversible ligands were important for determining [Cu2+] at ambient Cu levels in our samples.

Steam reforming of ethanol for hydrogen production over Cu/Co-Mg-Al-based catalysts prepared by hydrotalcite route.

PubMed

Homsi, Doris; Rached, Jihane Abou; Aouad, Samer; Gennequin, Cédric; Dahdah, Eliane; Estephane, Jane; Tidahy, Haingomalala Lucette; Aboukaïs, Antoine; Abi-Aad, Edmond

2017-04-01

The performances of different 5Cu/Co x Mg 6-x Al 2 (x = 0; 2; 4; 6) catalysts prepared by the wet impregnation method were investigated in the ethanol steam-reforming reaction (ESR) at 450 °C during 4 h under a steam/ethanol ratio of 3 (S/E = 3). The best catalyst among the prepared solids was 5Cu/Co 6 Al 2 as it showed a complete ethanol conversion and the highest hydrogen and carbon dioxide productivities. However, following 50 h of aging, the catalyst deactivated due to the formation of a high amount of carbonaceous products detected by differential scanning calorimetry/thermogravimetry. On the other hand, the 5Cu/Co 2 Mg 4 Al 2 catalyst showed a much lower quantity of coke deposition with no deactivation due to the basic character conferred by the magnesium oxide phase.

Enhanced luminescence in SrMgAl(x)O(17±δ):yMn4+ composite phosphors.

PubMed

Cao, Renping; Sharafudeen, Kaniyarakkal N; Qiu, Jianrong

2014-01-03

Red-emitting SrMgAlxO17±δ:yMn(4+) composite phosphors (x=10-100; y=0.05-4.0 mol%) are synthesized by solid-state reaction method in air. Addition of Al2O3 leads to the formation of two concomitant phases, i.e., SrMgAl10O17 and Al2O3 phases in the composite phosphor. Red emission from Mn(4+) ions in the composite phosphors is greatly enhanced due to multiple scattering and absorption of excitation light between SrMgAl10O17 and Al2O3 phases. SrMgAlxO17±δ:yMn(4+) composite phosphors would be a promising candidate as red phosphor in the application of a 397 nm near UV-based W-LED. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of Zr and Si on the Glass Forming Ability and Compressive Properties of Ti-Cu-Co-Sn Alloys

NASA Astrophysics Data System (ADS)

Wang, Tan; Wu, Yidong; Si, Jiajia; Hui, Xidong

2015-06-01

To succeed in finding novel Ti-based bulk metallic glasses, which are free from Be, Ni, and noble metallic elements, a comprehensive study was performed on the effects of Zr and Si on the microstructural evolution, glass-forming ability (GFA), and mechanical properties of Ti46Cu44- x Zr x Co7Sn3 ( x = 0, 5, 10, 12.5, and 16 at. pct) and Ti46Cu31.5Zr12.5- x Co7Sn3Si x ( x = 0.5, 1, and 1.5 at. pct) alloys. It is shown that with the increase of Zr, the sequence of phase formation is β-Ti + α-Ti + (Ti, Zr)3Cu4 ⇒ β-Ti + α-Ti + TiCu ⇒ β-Ti + Ti2Cu + glass ⇒ glass ⇒ β-Ti + Ti2Cu + TiCuSn. The quinary Ti-Zr-Cu-Co-Sn alloy with 12.5 pct Zr exhibits the best GFA. The addition of 1 pct Si results in the improvement of the critical size of glassy rods up to 3 mm in diameter. The yield stress and Young's modulus of Z-series alloys increases, and the plastic strain decreases with the addition of Zr. The yield stress and ultimate compression stress of Ti46Zr11.5Cu31.5Co7Sn3Si1 glassy alloy reach 2477.9 and 2623.3 MPa, respectively. It was found that the addition of Si promotes the generation and multiplication of shear bands, resulting in certain plasticity in these kinds of glassy alloys.

New model system in radiation cryochemistry:. hyperquenched glassy water

NASA Astrophysics Data System (ADS)

Bednarek, Janusz; Plonka, Andrzej; Hallbrucker, Andreas; Mayer, Erwin

1999-08-01

Radicals generated by high-energy irradiation of liquid water, short-lived at ambient temperature, can be studied at cryogenic temperatures after irradiating water and dilute aqueous solutions in their glassy states which can be obtained by so-called hyperquenching of the liquids at cooling rates of ˜10 6-10 7 K s -1. In the glassy states of hyperquenched dilute aqueous solutions there is no problem with phase separation and radiolysis of glassy water is quite distinct from radiolysis of polycrystalline ice obtained from liquid water on slow-cooling in liquid nitrogen.

High critical currents in heavily doped (Gd,Y)Ba 2Cu 3O x superconductor tapes

DOE PAGES

Selvamanickam, V.; Gharahcheshmeh, M. Heydari; Xu, A.; ...

2015-01-20

REBa 2Cu 3O x superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50 K and fields of 2–30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (J c) above 20 MA/cm 2 at 30 K, 3 T in heavily doped (25 mol. % Zr-added) (Gd,Y)Ba 2Cu 3O x superconductor tapes,more » which is more than three times higher than the J c typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m 3 have also been attained at 20 K. A composition map of lift factor in J c (ratio of J c at 30 K, 3 T to the J c at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO 3 (BZO) nanocolumn defect density of nearly 7 × 10 11 cm –2 as well as 2–3nm sized particles rich in Cu and Zr have been found in the high J c films.« less

Investigations on the Local Structures and the Spin Hamiltonian Parameters for Cu2+ in (90-x)TeO2-10GeO2-xWO3 Glasses

NASA Astrophysics Data System (ADS)

Feng, Chun-Rong; Jian, Jun; Chen, Xiao-Hong; Du, Quan; Wang, Ling

2017-12-01

The local structures and the spin Hamiltonian parameters (SHPs) for Cu2+ in (90-x)TeO2-10GeO2-xWO3 glasses are theoretically investigated at various WO3 concentrations (x=7.5, 15, 22.5 and 30 mol%). Subject to the Jahn-Teller effect, the [CuO6]10- groups are found to experience the small or moderate tetragonal elongation distortions (characterised by the relative tetragonal elongation ratios ρ≈0.35-3.09%) in C4 axis. With only three adjusted coefficients a, b and ω, the relevant model parameters (Dq, k and ρ) are described by the Fourier type and linear functions, respectively, and the measured concentration dependences of the d-d transition bands and SHPs are reproduced. The maximum of g∥ and the minimum of |A∥| at x=15 mol% are illustrated from the abrupt decrease of the copper-oxygen electron cloud admixtures or covalency and the obvious decline of the copper 3d-3s (4s) orbital admixtures due to the decreasing electron cloud density around oxygen ligands spontaneously bonding with Cu2+ and Te4+ (W6+), respectively.

41 CFR 60-30.22 - Official transcript.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Official transcript. 60-30.22 Section 60-30.22 Public Contracts and Property Management Other Provisions Relating to Public... ORDER 11246 Hearings and Related Matters § 60-30.22 Official transcript. The official transcripts of...

41 CFR 60-30.22 - Official transcript.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Official transcript. 60-30.22 Section 60-30.22 Public Contracts and Property Management Other Provisions Relating to Public... ORDER 11246 Hearings and Related Matters § 60-30.22 Official transcript. The official transcripts of...

Structural, elastic and electronic properties of typical NdMgT4 (T = Co, Ni, Cu) alloys from ab initio calculation

NASA Astrophysics Data System (ADS)

Wang, Na; Zhang, Wei-bing; Tang, Bi-yu; Gao, Hai-Tao; He, En-jie; Wang, Lei

2018-07-01

The crystal structure, elastic and magnetic properties of important ternary Mg-based alloys NdMgT4 (T = Co, Ni, Cu) have been studied using reliable ab initio calculations. Both cohesive energy and charge density difference suggest that three alloys have good structural stability with the order: NdMgCo4 > NdMgNi4 > NdMgCu4. It shows that NdMgCo4 alloy has magnetic moments with the Co atoms being the main contribution, which is also in agreement with the calculated electronic structures. We find that NdMgT4 (T = Co, Ni, Cu) alloys are all ductile materials with bulk-to-shear modulus (B/G) values higher than 1.75. The trends of calculated values for the shear moduli Cs and C44 are consistent with that of shear modulus G and young's modulus E, proving that NdMgT4 (T = Co, Ni, Cu) alloys exhibit good plasticity with the trend: NdMgNi4 > NdMgCu4 > NdMgCo4. These calculated results give the basis guidance for the design of rare earth-magnesium-transition metal (R-Mg-T) alloys with improved mechanical properties.

Thermodynamics of water sorption in high performance glassy thermoplastic polymers

PubMed Central

Scherillo, Giuseppe; Petretta, Mauro; Galizia, Michele; La Manna, Pietro; Musto, Pellegrino; Mensitieri, Giuseppe

2014-01-01

Sorption thermodynamics of water in two glassy polymers, polyetherimide (PEI) and polyetheretherketone (PEEK), is investigated by coupling gravimetry and on line FTIR spectroscopy in order to gather information on the total amount of sorbed water as well as on the different species of water molecules absorbed within the polymers, addressing the issue of cross- and self-interactions occurring in the polymer/water systems. Water sorption isotherms have been determined at temperatures ranging from 30 to 70°C while FTIR spectroscopy has been performed only at 30°C. The experimental analysis provided information on the groups present on the polymer backbones involved in hydrogen bonding interactions with absorbed water molecules. Moreover, it also supplied qualitative indications about the different “populations” of water molecules present within the PEEK and a quantitative assessment of these “populations” in the case of PEI. The results of the experimental analysis have been interpreted using an equation of state theory based on a compressible lattice fluid model for the Gibbs energy of the polymer-water mixture, developed by extending to the case of out of equilibrium glassy polymers a previous model intended for equilibrium rubbery polymers. The model accounts for the non-equilibrium nature of glassy polymers as well as for mean field and for hydrogen bonding interactions, providing a satisfactory quantitative interpretation of the experimental data. PMID:24860802

XAFS study of copper and silver nanoparticles in glazes of medieval middle-east lustreware (10th-13th century)

NASA Astrophysics Data System (ADS)

Padovani, S.; Puzzovio, D.; Sada, C.; Mazzoldi, P.; Borgia, I.; Sgamellotti, A.; Brunetti, B. G.; Cartechini, L.; D'Acapito, F.; Maurizio, C.; Shokoui, F.; Oliaiy, P.; Rahighi, J.; Lamehi-Rachti, M.; Pantos, E.

2006-06-01

It has recently been shown that lustre decoration of medieval and Renaissance pottery consists of silver and copper nanoparticles dispersed in the glassy matrix of the ceramic glaze. Here the findings of an X-ray absorption fine structure (XAFS) study on lustred glazes of shards belonging to 10th and 13rd century pottery from the National Museum of Iran are reported. Absorption spectra in the visible range have been also measured in order to investigate the relations between colour and glaze composition. Gold colour is mainly due to Ag nanoparticles, though Ag+, Cu+ and Cu2+ ions can be also dispersed within the glassy matrix, with different ratios. Red colour is mainly due to Cu nanoparticles, although some Ag nanoparticles, Ag+ and Cu+ ions can be present. The achievement of metallic Cu and the absence of Cu2+ indicate a higher reduction of copper in red lustre. These findings are in substantial agreement with previous results on Italian Renaissance pottery. In spite of the large heterogeneity of cases, the presence of copper and silver ions in the glaze confirms that lustre formation is mediated by a copper- and silver-alkali ion exchange, followed by nucleation and growth of metal nanoparticles.

Assessment of the mean glandular dose using LiF:Mg,Ti, LiF:Mg,Cu,P, Li2B4O7:Mn and Li2B4O7:Cu TL detectors in mammography radiation fields

NASA Astrophysics Data System (ADS)

Fartaria, M. J.; Reis, C.; Pereira, J.; Pereira, M. F.; Cardoso, J. V.; Santos, L. M.; Oliveira, C.; Holovey, V.; Pascoal, A.; Alves, J. G.

2016-09-01

The aim of this paper is the characterization of four thermoluminescence detectors (TLD), namely, LiF:Mg,Ti, LiF:Mg,Cu,P, Li2B4O7:Mn and Li2B4O7:Cu for the measurement of the entrance surface air kerma (ESAK) and estimation of the mean glandular dose (MGD) in digital mammography examinations at hospitals and clinics. Low-energy x-ray beams in the typical energy ranges of mammography, produced with a tungsten target and additional 60 µm molybdenum filtration were implemented and characterized at the Laboratory of Metrology of Ionizing Radiation at Instituto Superior Técnico. These beams were used for the characterization of the TLDs in terms of sensitivity, linearity, reproducibility, energy dependence and fading at 40 °C. The energy dependence test was further extended using clinical beams produced by mammography units at hospitals and clinics. The method proposed by the International Atomic Energy Agency was used for the measurement of ESAK and assessment of MGD. The combined standard uncertainty for the measurement of ESAK (and MGD) was determined in accordance to the Guide to the expression of uncertainty in measurement. The x-ray beams generated in the 23-40 kVp range presented HVL values from 0.36 to 0.46 mm Al. The beam produced at 28 kVp (HVL 0.39 mm Al) was considered as reference. The radiation field defined a circle with 84 mm diameter with a maximum variation of the beam intensity of less than 1% at the top flat (plateau) within 4 cm of the central axis. The estimated total uncertainty for the measurement of air kerma was 0.42%. All the TL detectors tested showed good performance except the commercial Li2B4O7:Mn (or TLD-800) which was excluded due to its poor sensitivity in our experimental set up. Both lithium fluorides showed better linearity and reproducibility as well as lower energy dependence and fading when compared to lithium borates. The stable behaviour of LiF:Mg,Ti and LiF:Mg,Cu,P detectors is reflected in the low combined standard

41 CFR 60-30.21 - Oral argument.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Oral argument. 60-30.21 Section 60-30.21 Public Contracts and Property Management Other Provisions Relating to Public Contracts... 11246 Hearings and Related Matters § 60-30.21 Oral argument. Any party shall be entitled upon request to...

41 CFR 60-30.21 - Oral argument.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Oral argument. 60-30.21 Section 60-30.21 Public Contracts and Property Management Other Provisions Relating to Public Contracts... 11246 Hearings and Related Matters § 60-30.21 Oral argument. Any party shall be entitled upon request to...

Efficacy and tolerability of the single-pill combination of aliskiren 300 mg/amlodipine 10 mg in hypertensive patients not controlled by olmesartan 40 mg/amlodipine 10 mg.

PubMed

Axthelm, Christoph; Sieder, Christian; Meister, Franziska; Kaiser, Edelgard

2012-01-01

We aimed to investigate whether the single pill combination (SPC) of aliskiren 300 mg and amlodipine 10 mg (ALIS 300/AMLO 10) improves blood pressure (BP) reduction in hypertensive patients not adequately controlled by the SPC olmesartan 40 mg and amlodipine 10 mg (OLM 40/AMLO 10). Open-label, non-randomized single-arm study. Patients with stage 2 hypertension were titrated to the SPC OLM 40/AMLO 10 (4-week Phase 1). If hypertension was not controlled they were switched to the SPC ALIS 300/AMLO 10 (4-week Phase 2). In the optional 4-week study extension hydrochlorothiazide (HCT) 12.5 mg was added. EudraCT 2009-016693-33. In the 342 patients treated, OLM 40/AMLO 10 reduced systolic BP (SBP)/diastolic BP (DBP) by 24.5/14.5 mmHg by end of Phase 1. Those 187 patients with uncontrolled hypertension at the end of Phase 1 switched to ALIS 300/AMLO 10 experienced a further SBP reduction of 5.1 mmHg (95% confidence interval [CI] 3.7 to 6.5, p < 0.0001) and a DBP reduction of 4.8 mmHg (95% CI 3.8 to 5.8; p < 0.0001) in Phase 2. DBP or SBP responder rates were achieved by 51.3% or 44.4%, respectively, SBP and DBP normalization by 36.4%. In 65 patients whose BP was not controlled in Phase 2, SPC ALIS 300/AMLO 10/HCT 12.5 mg decreased SBP/DBP by further 8.1/6.7 mmHg (p < 0.0001 each). No deaths or serious adverse events were noted. Significant adverse events leading to study discontinuation were reported in 2.6% (Phase 1), 2.7% (Phase 2), and 0% (extension). Limitations included the open-label, single-arm non-randomized design, and the relatively short duration. In this switch study reflecting clinical practice, patients with moderate hypertension not controlled by the SPC OLM 40/AMLO 10 achieved a clinically and statistically significant reduction of blood pressure from the SPC ALIS 300/AMLO 10 and the optional addition of HCT. All drug combinations were well tolerated.

The Solar Twin Planet Search. III. The [Y/Mg] clock: estimating stellar ages of solar-type stars

NASA Astrophysics Data System (ADS)

Tucci Maia, M.; Ramírez, I.; Meléndez, J.; Bedell, M.; Bean, J. L.; Asplund, M.

2016-05-01

Context. Solar twins are stars with similar stellar (surface) parameters to the Sun that can have a wide range of ages. This provides an opportunity to analyze the variation of their chemical abundances with age. Nissen (2015, A&A, 579, A52) recently suggested that the abundances of the s-process element Y and the α-element Mg could be used to estimate stellar ages. Aims: This paper aims to determine with high precision the Y, Mg, and Fe abundances for a sample of 88 solar twins that span a broad age range (0.3-10.0 Gyr) and investigate their use for estimating ages. Methods: We obtained high-quality Magellan Inamori Kyocera Echelle (MIKE) spectra and determined Y and Mg abundances using equivalent widths and a line-by-line differential method within a 1D LTE framework. Stellar parameters and iron abundances were measured in Paper I of this series for all stars, but a few (three) required a small revision. Results: The [Y/Mg] ratio shows a strong correlation with age. It has a slope of -0.041 ± 0.001 dex/Gyr and a significance of 41σ. This is in excellent agreement with the relation first proposed by Nissen (2015). We found some outliers that turned out to be binaries where mass transfer may have enhanced the yttrium abundance. Given a precise measurement of [Y/Mg] with typical error of 0.02 dex in solar twins, our formula can be used to determine a stellar age with ~0.8 Gyr precision in the 0 to 10 Gyr range. Based on observations obtained at the Clay Magellan Telescopes at Las Campanas Observatory, Chile and at the 3.6 m Telescope at the La Silla ESO Observatory, Chile (program ID 188.C-0265).

Aspects of forming metal-clad melt-processed Y-Ba-Cu-O tapes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozlowski, G.; Oberly, C.E.; Ho, J.

1991-03-01

This paper reports on melt-processing of Y-Ba-Cu-O superconductor in a usable form for magnet winding which requires the development of a cladding with demanding properties. Numerous recent efforts in cold forming Bi-based superconductor tapes have been successful because a silver tube can be used to constrain the ceramic material, which is sintered at much lower temperature than the Y-Ba-Cu-O. Typical high temperature metals which can be used to encase Y-Ba-Cu-O during sintering do not permit ready diffusion of oxygen as silver does. Recently, the full or partial recovery of superconductivity has been achieved in transition-metal- doped Y-Ba-Cu-O due to themore » partial-melt processing.« less

41 CFR 60-30.30 - Final Administrative Order.

Code of Federal Regulations, 2011 CFR

2011-07-01

... EXECUTIVE ORDER 11246 Post-Hearing Procedures § 60-30.30 Final Administrative Order. After expiration of the... appropriate, or any of the above. In any event, failure to comply with the Administrative order shall result...

Amperometric sensing of hydrogen peroxide using glassy carbon electrode modified with copper nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sophia, J.; Muralidharan, G., E-mail: muraligru@gmail.com

2015-10-15

In this paper, fabrication of glassy carbon electrode (GCE) modified with nano copper particles is discussed. The modified electrode has been tested for the non-enzymatic electrochemical detection of hydrogen peroxide (H{sub 2}O{sub 2}). The copper nanoparticles (Cu NPs) were prepared employing a simple chemical reduction method. The presence of Cu NPs was confirmed through UV–visible (UV–vis) absorption spectroscopy and X-ray diffraction (XRD) analysis. The size and morphology of the particles were investigated using transmission electron microscopy (TEM). The electrochemical properties of the fabricated sensor were studied via cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The electrochemical sensor displayedmore » excellent performance features towards H{sub 2}O{sub 2} detection exhibiting wide linear range, low detection limit, swift response time, good reproducibility and stability.« less

Vertical Geochemical Variations and Speciation Studies of As, Fe, Mn, Zn, and Cu in the Sediments of the Central Gangetic Basin: Sequential Extraction and Statistical Approach

PubMed Central

Ramanathan, AL.

2018-01-01

A geochemical and speciation study of As, Fe, Mn, Zn, and Cu was performed using sequential extraction and statistical approaches in the core sediments taken at two locations—Rigni Chhapra and Chaube Chhapra—of the central Gangetic basin (India). A gradual increase in the grain size (varying from clay to coarse sands) was observed in both the core profiles up to 30.5 m depth. The concentrations of analyzed elements ranged as follows: 6.9–14.2 mg/kg for As, 13,849–31,088 mg/kg for Fe, 267–711 mg/kg for Mn, 45–164 mg/kg for Cu for Rigni Chhapra while for Chaube Chhapra the range was 7.5–13.2 mg/kg for As, 10,936–37,052 mg/kg for Fe, 267–1052 mg/kg for Mn, 60–198 mg/kg for Zn and 60–108 mg/kg for Cu. Significant amounts (53–95%) of all the fractionated elemental concentrations were bound within the crystal structure of the minerals as a residual fraction. The reducible fraction was the second most dominant fraction for As (7% and 8%), Fe (3%), Mn (20% and 26%), and Cu (7% and 6%) respectively for both the cores. It may be released when aquifers subjected to changing redox conditions. The acid soluble fraction was of most interest because it could quickly mobilize into the water system which formed the third most dominating among all three fractions. Four color code of sediments showed an association with total As concentration and did not show a relation with any fraction of all elements analyzed. The core sediment was observed enriched with As and other elements (Cu, Fe, Mn, and Zn). However, it fell under uncontaminated to moderately contaminate which might exhibit a low risk in prevailing natural conditions. X-ray diffraction analyses indicated the availability of siderite and magnetite minerals in the core sediments in a section of dark grey with micaceous medium sand with organic matter (black). PMID:29360767

Spray-Pyrolyzed Three-Dimensional CuInS2 Solar Cells on Nanocrystalline-Titania Electrodes with Chemical-Bath-Deposited Inx(OH)ySz Buffer Layers

NASA Astrophysics Data System (ADS)

Nguyen, Duy-Cuong; Mikami, Yuki; Tsujimoto, Kazuki; Ryo, Toshihiro; Ito, Seigo

2012-10-01

Three-dimensional (3D) compound solar cells with the structure of CuInS2/Inx(OH)ySz/porous TiO2/compact TiO2/florin-doped tin-oxide-coated glass plates> have been fabricated by spray pyrolysis deposition of CuInS2 and chemical-bath deposition of Inx(OH)ySz for the light absorber and buffer layer, respectively. The effect of deposition and annealing conditions of Inx(OH)ySz on the photovoltaic properties of 3D CuInS2 solar cells was investigated. Inx(OH)ySz annealed in air ambient showed a better cell performance than those annealed in nitrogen ambient and without annealing. The improvement of the performance of cells with Inx(OH)ySz buffer layers annealed in air ambient is due to the increase in oxide concentration in the buffer layers [confirmed by X-ray photoelectron spectroscopy (XPS) measurement]. Among cells with Inx(OH)ySz buffer layers deposited for 1, 1.5, 1.75, and 2 h, that with Inx(OH)ySz deposited for 1.75 h showed the best cell performance. The best cell performance was observed for Inx(OH)ySz deposited for 1.75 h with annealing at 300 °C for 30 min in air ambient, and cell parameters were 22 mA cm-2 short-circuit photocurrent density, 0.41 V open-circuit voltage, 0.35 fill factor, and 3.2% conversion efficiency.

Superconductivity of Cu/CuOx interface formed by shock-wave pressure

NASA Astrophysics Data System (ADS)

Shakhray, D. V.; Avdonin, V. V.; Palnichenko, A. V.

2016-11-01

A mixture of powdered Cu and CuO has been subjected to shock-wave pressure of 350 kbar with following quenching of the vacuum-encapsulated product to 77 K. The ac magnetic susceptibility measurements of the samples have revealed metastable superconductivity with Tc ≈ 19 K, characterized by glassy dynamics of the shielding currents below Tc . Comparison of the ac susceptibility and the DC magnetization measurements infers that the superconductivity arises within the granular interfacial layer formed between metallic Cu and its oxides due to the shock-wave treatment.

Critical current density of TlBa 2Ca 2Cu 3O 9 thin films on MgO (100) in magnetic fields

NASA Astrophysics Data System (ADS)

Piehler, A.; Ströbel, J. P.; Reschauer, N.; Löw, R.; Schönberger, R.; Renk, K. F.; Kraus, M.; Daniel, J.; Saemann-Ischenko, G.

1994-04-01

We report on the critical current density of TlBa 2Ca 2Cu 3O 9 thin films on (100) MgO substrates in magnetic fields. Single- phase and highly c-axis oriented thin films were prepared by laser ablation in combination with thermal evaporation of Tl 2O 3. Scanning electron microscope investigations indicated a flat plate-like microstructure and DC magnetization measurements showed the onset of superconductivity at ∼ 115 K. The critical current density jc was determined from magnetization cycles. Typical values of jc were 9 × 10 5 A/cm 2 at 6 K and 2.5 × 10 5 A/cm 2 at 77 K. In a magnetic field to 1 T applied parallel to the c-axis the critical current densities were 3 × 10 5 A/cm 2 at 6 K and 3 × 10 3 A/cm 2 at 77 K. The decrease of jc at higher magnetic fields is discussed and attributed to the microstructure of the TlBa 2Ca 2Cu 3O 9 thin films.

TL-OSL study of Li{sub 3}PO{sub 4}: Mg, Cu phosphor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahangdale, S. R., E-mail: sachin.rahangdale1@gmail.com; Wankhede, S. P.; Dhabekar, B. S.

In the present work, we report the thermoluminescence and optically stimulated luminescence properties of Mg and Cu doped Li{sub 3}PO{sub 4} phosphor. The phosphor was synthesized by precipitation method. The thermoluminescence dosimetric peak temperature for the phosphor varies with concentrations of Mg and Cu. Li{sub 3}PO{sub 4} shows good response to 470nm optical stimulation. The OSL sensitivity of the phosphor is approximately 12 times than that of standard Lithium magnesium phosphate. This study may help to develop this material for the application in real time dosimetry using optically stimulated luminescence.

DFT investigation of the vibrational properties of GC Watson-Crick and Hoogsteen base pairs in the presence of Mg²⁺, Ca²⁺, and Cu²⁺ ions.

PubMed

Morari, Cristian; Muntean, Cristina M; Tripon, Carmen; Buimaga-Iarinca, Luiza; Calborean, Adrian

2014-04-01

The binding effects of Mg²⁺, Ca²⁺, and Cu²⁺ ions on the vibrational properties of guanine-cytosine base pairs have been performed using density functional theory investigations. Both Watson-Crick and Hoogsteen configurations of the base pairs were investigated. In Watson-Crick configuration, the metal was coordinated at N7 atom of guanine, while in the case of Hoogsteen configuration, the coordination is at N3 atom of guanine. We have pointed out the geometric properties of the metal-GC base pairs structure, as well as the vibrational bands that can be used to detect the presence of metallic ions in the Watson-Crick and Hoogsteen GC structures. For the geometric models used by us, the vibrational amplitudes of metallic atoms were stronger for wavenumbers lower than 500 cm⁻¹. This suggests that in the experimental studies on DNA the presence of the three metallic atoms (Mg, Ca, and Cu) can be explicitly detected at low frequencies.

Yttrium enrichment and improved magnetic properties in partially melted Y-Ba-Cu-O materials

NASA Technical Reports Server (NTRS)

Alterescu, Sidney; Hojaji, Hamid; Barkatt, Aaron; Michael, Karen A.; Hu, Shouxiang

1990-01-01

The yttrium-rich compositions in the Y-Ba-Cu-O system were mapped out in a systematic manner to quantify their magnetic properties and to correlate them with the microstructure and phase composition as determined by scanning electron microscopy and X-ray diffraction analysis. It is found that the microstructure of Y-Ba-Cu-O compositions is a sensitive function of both their composition and processing conditions. Measurements of magnetic susceptibility and maximum (low-field) and remanent magnetization for the system Y:Ba:Cu = x:2:3 show highest values for x = 2. The corresponding structures involve numerous small crystals of Y2BaCuO5 (211) embedded in highly ordered assemblages of continous YBa2Cu3O(7-y) (123) layers.

Irreversibility and critical current density of FeSr2ErCu2O6+y

NASA Astrophysics Data System (ADS)

Hata, Y.; Iida, I.; Mochiku, T.; Yasuoka, H.

2018-03-01

FeSr2ErCu2O6+y (ErFe1212) and non-superconducting FeSr2ErCu1.9Zn0.1O6+y were synthesized to study the property of the superconductivity and the irreversibility of ErFe1212. A large irreversibility in the temperature dependence of magnetization and a hysteresis in the magnetization curve were observed in ErFe1212. By comparison with non-superconducting FeSr2ErCu1.9Zn0.1O6+y, it was found that the most part of the hysteresis at high magnetic eld originates from the magnetism of Fe ion and some part of the hysteresis at low magnetic eld originates from the superconductivity. Using the magnetization curve of ErFe1212 and FeSr2ErCu1.9Zn0.1O6+y, the J c of ErFe1212 in individual grains at 10 K under 0.1 T was estimated by the Bean model and {J}\\text{c}\\text{intra} was 2.6 × 109 A/m2. The critical current density across inter-grain boundaries at 10 K estimated by V ‑ I measurement was {J}\\text{c}\\text{intra} = 5.7 × 104 A/m2. A large difference between {J}\\text{c}\\text{intra} and {J}\\text{c}\\text{intra} was observed in ErFe1212. {J}\\text{c}\\text{intra} and {J}\\text{c}\\text{intra} of ErFe1212 are 2.2 and 5.2 times larger than these of YFe1212, respectively.

Structural, dielectric and ferroelectric studies of BZT doped Mg0.2Cu0.3Zn0.5Fe2O4 magnetoelectric composites

NASA Astrophysics Data System (ADS)

Khader, S. Abdul; Parveez, Asiya; Giridharan, N. V.; Sankarappa, T.

2018-05-01

The composites of ferrite-ferroelectric system (x) Mg0.2Cu0.3Zn0.5Fe2O4+ (1-x) Ba0.8Zr0.2TiO3 (x=15%, 30%, 45%) were synthesized by sintering mixtures of ferroelectric Ba0.8Zr0.2TiO3 (BZT) and ferrite component Mg0.2Cu0.3Zn0.5Fe2O4 (MCZF). The presences of two phases in magneto-electric composites were probed by X-ray diffraction (XRD) studies. The peaks observed in the XRD spectrum indicated spinel cubic structure for MCZF ferrite and tetragonal perovskite structure for BZT and, both spinel and pervoskite structures for synthesized composites. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM). Frequency dependent dielectric properties of synthesized composites were measured from 100 Hz to 1 MHz at RT using HIOKI LCR HI-TESTER. The dielectric dispersion is observed at lower frequencies for the synthesized ME composites. The ferroelectric properties of synthesized composites were analyzed using a Precision ferroelectric tester. It is observed that the composites exhibited ferroelectric hysteresis with wide loops indicating lossy nature of composites.

Novel synthesis and characterization of pristine Cu nanoparticles for the non-enzymatic glucose biosensor.

PubMed

Dayakar, T; Rao, K Venkateswara; Bikshalu, K; Rajendar, V; Park, Si-Hyun

2017-07-01

Non enzymatic electrochemical glucose sensing was developed based on pristine Cu Nanopartilces (NPs)/Glassy Carbon Electrode (GCE) which can be accomplished by simple green method via ocimum tenuiflorum leaf extract. Then, the affect of leaf extract addition on improving Structural, Optical and electrochemical properties of pristine cu NPs was investigated. The synthesized Cu NPs were characterized with X-ray diffraction (X-ray), Uv-Visible spectroscopy (Uv-Vis), Fourier transformation infrared spectroscopy (FTIR), Particle size distribution (PSA), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), Transmission electron microscopy (TEM) for structural optical and morphological studies respectively. The synthesized Cu NPs were coated over glassy carbon electrode (GCE) to study the electrochemical response of glucose by cyclic voltammetry and ampherometer. The results indicates that the modified biosensor shows a remarkable sensitivity (1065.21 μA mM -1  cm -2 ), rapid response time (<3s), wide linear range (1 to 7.2 mM), low detection limit (0.038 μM at S/N = 3). Therefore, the prepared Cu NPs by the Novel Bio-mediated route were exploited to construct a non-enzymatic glucose biosensor for sustainable clinical field applications.

Al-Cu-Li and Al-Mg-Li alloys: Phase composition, texture, and anisotropy of mechanical properties (Review)

NASA Astrophysics Data System (ADS)

Betsofen, S. Ya.; Antipov, V. V.; Knyazev, M. I.

2016-04-01

The results of studying the phase transformations, the texture formation, and the anisotropy of the mechanical properties in Al-Cu-Li and Al-Mg-Li alloys are generalized. A technique and equations are developed to calculate the amounts of the S1 (Al2MgLi), T1 (Al2CuLi), and δ' (Al3Li) phases. The fraction of the δ' phase in Al-Cu-Li alloys is shown to be significantly higher than in Al-Mg-Li alloys. Therefore, the role of the T1 phase in the hardening of Al-Cu-Li alloys is thought to be overestimated, especially in alloys with more than 1.5% Li. A new model is proposed to describe the hardening of Al-Cu-Li alloys upon aging, and the results obtained with this model agree well with the experimental data. A texture, which is analogous to that in aluminum alloys, is shown to form in sheets semiproducts made of Al-Cu-Li and Al-Mg-Li alloys. The more pronounced anisotropy of the properties of lithium-containing aluminum alloys is caused by a significant fraction of the ordered coherent δ' phase, the deformation mechanism in which differs radically from that in the solid solution.

The [Y/Mg] clock works for evolved solar metallicity stars

NASA Astrophysics Data System (ADS)

Slumstrup, D.; Grundahl, F.; Brogaard, K.; Thygesen, A. O.; Nissen, P. E.; Jessen-Hansen, J.; Van Eylen, V.; Pedersen, M. G.

2017-08-01

Aims: Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. Methods: High resolution and high signal-to-noise ratio (S/N) spectroscopic data of stars in the helium-core-burning phase have been obtained with the FIES spectrograph on the NOT 2.56 m telescope and the HIRES spectrograph on the Keck I 10 m telescope. They have been analyzed to determine the chemical abundances of four open clusters with close to solar metallicity; NGC 6811, NGC 6819, M 67 and NGC 188. The abundances are derived from equivalent widths of spectral lines using ATLAS9 model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Results from asteroseismology and binary studies were used as priors on the atmospheric parameters, where especially the log g is determined to much higher precision than what is possible with spectroscopy. Results: It is confirmed that the four open clusters are close to solar metallicity and they follow the [Y/Mg] vs. age trend previously found for solar twins. Conclusions: The [Y/Mg] vs. age clock also works for giant stars in the helium-core burning phase, which vastly increases the possibilities to estimate the age of stars not only in the solar neighborhood, but in large parts of the Galaxy, due to the brighter nature of evolved stars compared to dwarfs. Based on spectroscopic observations made with two telescopes: the Nordic Optical Telescope operated by NOTSA at the Observatorio del Roque de los Muchachos (La Palma, Spain) of the Instituto de Astrofísica de Canarias and the Keck I Telescope at the W.M. Keck Observatory (Mauna Kea, Hawaii, USA) operated by the California Institute of Technology, the University of California and the National Aeronautics and Space Administration.

Acid-suppressive efficacy of a reduced dosage of rabeprazole: comparison of 10 mg twice daily rabeprazole with 20 mg twice daily rabeprazole, 30 mg twice daily lansoprazole, and 20 mg twice daily omeprazole by 24-hr intragastric pH-metry.

PubMed

Shimatani, Tomohiko; Inoue, Masaki; Kuroiwa, Tomoko; Xu, Jing; Tazuma, Susumu; Horikawa, Yoko; Nakamura, Masuo

2005-07-01

Rabeprazole achieves more potent acid suppression than other proton pump inhibitors. Therefore it is administered at reduced as well as high dosages in eradication therapy for Helicobacter pylori; however, there is incomplete assessment of the efficacy of a reduced dosage of rabeprazole as might be employed in therapy. In this study, we evaluated acid-suppressive efficacy of a reduced dosage of rabeprazole on day 7 by 24-hr pH-metry in 10 healthy male cytochrome P-450 2C19 extensive metabolizers without Helicobacterpylori infection and compared the results with those of high dosages of rabeprazole, lansoprazole, and omeprazole. Median intragastric pH value, pH >3 holding time ratio (pH>3HT), pH>4HT, pH>5HT, pH>6HT, and pH>7HT for 24 hr with rabeprazole, 10 mg twice daily, were not significantly different from those of rabeprazole, 20 mg twice daily, lansoprazole, 30 mg twice daily, and omeprazole, 20 mg twice daily. In conclusion, for acid-suppressive efficacy, a reduced dosage of rabeprazole is comparable to high dosages of rabeprazole, lansoprazole, and omeprazole.

Cryogenic and elevated temperature strengths of an Al-Zn-Mg-Cu alloy modified with Sc and Zr

NASA Astrophysics Data System (ADS)

Senkova, S. V.; Senkov, O. N.; Miracle, D. B.

2006-12-01

The effect of minor additions of Sc and Zr on tensile properties of two developmental Al-Zn-Mg-Cu alloys was studied in the temperature range -196°C to 300°C. Due to the presence of Sc and Zr in a fine dispersoid form, both low-temperature and elevated temperature strengths of these alloys are much higher than those of similar 7000 series alloys that do not contain these elements. After short holding times (up to 10 hours) at 205°C, the strength of these alloys is higher than those of high-temperature Al alloys 2219-T6 and 2618-T6; however, the latter alloys show better strength after longer holding times. It is suggested that additional alloying of the Sc-containing Al-Zn-Mg-Cu alloys with other dispersoid-forming elements, such as Ni, Fe, Mn, and Si, with a respective decrease in the amounts of Zn and Mg may further improve the elevated temperature strength and decrease the loss of strength with extended elevated temperature exposure.

Pancreatic polypeptide and its central Y4 receptors are essential for cued fear extinction and permanent suppression of fear

PubMed Central

Verma, D; Hörmer, B; Bellmann‐Sickert, K; Thieme, V; Beck‐Sickinger, A G; Herzog, H; Sperk, G

2016-01-01

Background and purpose Avoiding danger and finding food are closely related behaviours that are essential for surviving in a natural environment. Growing evidence supports an important role of gut‐brain peptides in modulating energy homeostasis and emotional‐affective behaviour. For instance, postprandial release of pancreatic polypeptide (PP) reduced food intake and altered stress‐induced motor activity and anxiety by activating central Y4 receptors. Experimental approach We characterized [K30(PEG2)]hPP2‐36 as long‐acting Y4 receptor agonist and injected it peripherally into wildtype and Y4 receptor knockout (Y4KO) C57Bl/6NCrl mice to investigate the role of Y4 receptors in fear conditioning. Extinction and relapse after extinction was measured by spontaneous recovery and renewal. Key results The Y4KO mice showed impaired cued and context fear extinction without affecting acquisition, consolidation or recall of fear. Correspondingly, peripheral injection of [K30(PEG2)]hPP2‐36 facilitated extinction learning upon fasting, an effect that was long‐lasting and generalized. Furthermore, peripherally applied [K30(PEG2)]hPP2‐36 before extinction inhibited the activation of orexin‐expressing neurons in the lateral hypothalamus in WT, but not in Y4KO mice. Conclusions and implications Our findings suggests suppression of excessive arousal as a possible mechanism for the extinction‐promoting effect of central Y4 receptors and provide strong evidence that fear extinction requires integration of vegetative stimuli with cortical and subcortical information, a process crucially depending on Y4 receptors. Importantly, in the lateral hypothalamus two peptide systems, PP and orexin, interact to generate an emotional response adapted to the current homeostatic state. Detailed investigations of feeding‐relevant genes may thus deliver multiple intervention points for treating anxiety‐related disorders. PMID:26844810

41 CFR 60-30.29 - Record.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Record. 60-30.29 Section 60-30.29 Public Contracts and Property Management Other Provisions Relating to Public Contracts...-RULES OF PRACTICE FOR ADMINISTRATIVE PROCEEDINGS TO ENFORCE EQUAL OPPORTUNITY UNDER EXECUTIVE ORDER...

Direct Quantification of Cd2+ in the Presence of Cu2+ by a Combination of Anodic Stripping Voltammetry Using a Bi-Film-Modified Glassy Carbon Electrode and an Artificial Neural Network.

PubMed

Zhao, Guo; Wang, Hui; Liu, Gang

2017-07-03

Abstract : In this study, a novel method based on a Bi/glassy carbon electrode (Bi/GCE) for quantitatively and directly detecting Cd 2+ in the presence of Cu 2+ without further electrode modifications by combining square-wave anodic stripping voltammetry (SWASV) and a back-propagation artificial neural network (BP-ANN) has been proposed. The influence of the Cu 2+ concentration on the stripping response to Cd 2+ was studied. In addition, the effect of the ferrocyanide concentration on the SWASV detection of Cd 2+ in the presence of Cu 2+ was investigated. A BP-ANN with two inputs and one output was used to establish the nonlinear relationship between the concentration of Cd 2+ and the stripping peak currents of Cu 2+ and Cd 2+ . The factors affecting the SWASV detection of Cd 2+ and the key parameters of the BP-ANN were optimized. Moreover, the direct calibration model (i.e., adding 0.1 mM ferrocyanide before detection), the BP-ANN model and other prediction models were compared to verify the prediction performance of these models in terms of their mean absolute errors (MAEs), root mean square errors (RMSEs) and correlation coefficients. The BP-ANN model exhibited higher prediction accuracy than the direct calibration model and the other prediction models. Finally, the proposed method was used to detect Cd 2+ in soil samples with satisfactory results.

Magnetic order tuned by Cu substitution in Fe 1.1–zCu zTe

DOE PAGES

Wen, Jinsheng; Xu, Zhijun; Xu, Guangyong; ...

2012-07-02

We study the effects of Cu substitution in Fe₁.₁Te, the nonsuperconducting parent compound of the iron-based superconductor, Fe₁₊ yTe₁₋ xSe x, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at ~60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5–δ, 0, 0.5) with δ being the incommensurability of 0.02, and correlation length of 12 Å along the a axis and 9 Åmore » along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first-order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has a large effect on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.« less

Effect of Cu content on the microstructure evolution and fracture behavior of Al-Mg-Si-xCu (x  =  0, 1, 2 and 4 wt.%) alloys

NASA Astrophysics Data System (ADS)

Rahman, Tanzilur; Sakib Rahman, Saadman; Zurais Ibne Ashraf, Md; Ibn Muneer, Khalid; Rashed, H. M. Mamun Al

2017-10-01

Lightweighting automobiles can dramatically reduce their consumption of fossil fuels and the atmospheric CO2 concentration. Heat-treatable Al-Mg-Si has attracted a great deal of research interest due to their high strength-to-weight ratio, good formability, and resistance to corrosion. In the past, it has been reported that the mechanical properties of Al-Mg-Si can be ameliorated by the addition of Cu. However, determining the right amount of Cu content still remains a challenge. To address this the microstructure evolution, phase transformation, mechanical properties, and fracture behavior of Al-Mg-Si-xCu (x  =  0, 1, 2 and 4 wt.%) alloys were studied through optical and field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, differential scanning calorimetry, hardness measurements, and tensile tests. The obtained results indicate that the addition of Cu of up to 4 wt.% improved the hardness (17.5% increase) of the alloy, but reduced its ductility. Moreover, an alloy with 4 wt.% Cu fractured in a brittle manner while Al-Mg-Si showed ductile fracture mechanism. In addition, differential scanning calorimetry analysis revealed five exothermic peaks in all Cu containing alloys. Our results also showed that θʹ and Qʹ-type intermetallic phases formed owing to the addition of Cu, which affected the strength and ductility. Thus, Al-Mg-Si-xCu alloy with the right amount of Cu content serves as an excellent candidate for replacing more costly alloys for cost-effective lightweighting and other applications.

Comparison of the TL responses of two different preparations of LiF:Mg,Cu,P irradiated by photons of various energies.

PubMed

González, P R; Furetta, C; Azorín, J

2007-03-01

The aim of this work is to present the results concerning the photon irradiation of a new phosphor, the LiF:Mg,Cu,P+PTFE, produced at the Instituto Nacional de Investigaciones Nucleares (ININ-Mexico). The photon irradiations were performed using X-rays of 16, 24, 34.5, 42, 100 and 145keV, and gamma rays from (137)Cs (662keV) and from (60)Co (1 252keV). The results obtained are normalized to the (60)Co response. The experimental data are then compared to those obtained using the commercial dosimeters TLD-100 and GR-200A.

Evaluation of the microstructure of Al-Cu-Li-Ag-Mg Weldalite (tm) alloys, part 4

NASA Technical Reports Server (NTRS)

Pickens, Joseph R.; Kumar, K. S.; Brown, S. A.; Gayle, Frank W.

1991-01-01

Weldalite (trademark) 049 is an Al-Cu-Li-Ag-Mg alloy designed to have ultrahigh strength and to serve in aerospace applications. The alloy displays significantly higher strength than competitive alloys in both naturally aged and artificially aged tempers. The strengthening phases in such tempers have been identified to, in part, explain the mechanical properties attained. In general, the alloy is strengthened by delta prime Al3Li and Guinier-Preston (GP) zones in the naturally aged tempers. In artificially aged tempers in slightly underaged conditions, strengthening is provided by several phases including GP zones, theta prime Al2Cu, S prime Al2CuMg, T(sub 1) Al2CuLi, and possibly a new phase. In the peak strength artificially aged tempers, T(sub 1) is the predominant strengthening phase.

40 CFR 60.30d - Designated facilities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Designated facilities. 60.30d Section... Acid Production Units § 60.30d Designated facilities. Sulfuric acid production units. The designated facility to which §§ 60.31d and 60.32d apply is each existing “sulfuric acid production unit” as defined in...

Esomeprazole 40 mg provides more effective intragastric acid control than lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg in patients with gastro-oesophageal reflux symptoms.

PubMed

Röhss, Kerstin; Lind, Tore; Wilder-Smith, Clive

2004-10-01

To compare the effect of esomeprazole 40 mg with lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg on intragastric pH during single and repeated dosing in four separate studies in patients with symptoms of gastro-oesophageal reflux disorder (GERD). In four randomised crossover studies, patients with symptoms of GERD received once-daily treatment with esomeprazole 40 mg or lansoprazole 30 mg (study A), omeprazole 20 mg (study B), pantoprazole 40 mg (study C) and rabeprazole 20 mg (study D) for 5 days. Continuous 24-h intragastric pH recording was performed on days 1 (except study B) and 5. Percentage of time over 24 h with intragastric pH greater than 4, 24-h median pH and the proportion of patients with pH greater than 4 for greater than or equal to 12 h and 16 h during the 24-h recording periods were investigated. In all four studies, esomeprazole 40 mg OD maintained intragastric pH greater than 4 for a significantly higher mean percentage of the 24-h period compared with all other proton pump inhibitors (PPIs) on days 1 (esomeprazole 40.6% versus lansoprazole 33.4%, P=0.0182; esomeprazole 50.3% versus pantoprazole 29.1%, P<0.001; esomeprazole 41.0% versus rabeprazole 29.4%, P=0.002) and 5 (esomeprazole 57.7% versus lansoprazole 44.5%, P<0.0001; esomeprazole 69.8% versus omeprazole 43.7%, P<0.0001; esomeprazole 67.0% versus pantoprazole 44.8%, P<0.001; esomeprazole 59.4% versus rabeprazole 44.5%, P<0.0001). Higher 24-h median pH and a higher proportion of patients with intragastric pH greater than 4 for greater than or equal to 12 h and 16 h were reported with esomeprazole 40 mg OD than with all the other PPIs in each study. Esomeprazole 40 mg provides greater acid control in more patients and maintains intragastric pH greater than 4 for a longer period than lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg in patients with symptoms of GERD.

Entanglement of solid vortex matter: a boomerang-shaped reduction forced by disorder in interlayer phase coherence in Bi2Sr2CaCu2O8+y.

PubMed

Kato, T; Shibauchi, T; Matsuda, Y; Thompson, J R; Krusin-Elbaum, L

2008-07-11

We present evidence for entangled solid vortex matter in a glassy state in a layered superconductor Bi2Sr2CaCu2O8+y containing randomly splayed linear defects. The interlayer phase coherence--probed by the Josephson plasma resonance--is enhanced at high temperatures, reflecting the recoupling of vortex liquid by the defects. At low temperatures in the vortex solid state, the interlayer coherence follows a boomerang-shaped reentrant temperature path with an unusual low-field decrease in coherence, indicative of meandering vortices. We uncover a distinct temperature scaling between in-plane and out-of-plane critical currents with opposing dependencies on field and time, consistent with the theoretically proposed "splayed-glass" state.

Understanding the Interface Dipole of Copper Phthalocyanine (CuPc)/C60: Theory and Experiment.

PubMed

Sai, Na; Gearba, Raluca; Dolocan, Andrei; Tritsch, John R; Chan, Wai-Lun; Chelikowsky, James R; Leung, Kevin; Zhu, Xiaoyang

2012-08-16

Interface dipole determines the electronic energy alignment in donor/acceptor interfaces and plays an important role in organic photovoltaics. Here we present a study combining first principles density functional theory (DFT) with ultraviolet photoemission spectroscopy (UPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to investigate the interface dipole, energy level alignment, and structural properties at the interface between CuPc and C60. DFT finds a sizable interface dipole for the face-on orientation, in quantitative agreement with the UPS measurement, and rules out charge transfer as the origin of the interface dipole. Using TOF-SIMS, we show that the interfacial morphology for the bilayer CuPc/C60 film is characterized by molecular intermixing, containing both the face-on and the edge-on orientation. The complementary experimental and theoretical results provide both insight into the origin of the interface dipole and direct evidence for the effect of interfacial morphology on the interface dipole.

Relationship of boreal summer 10-20-day and 30-60-day intraseasonal oscillation intensity over the tropical western North Pacific to tropical Indo-Pacific SST

NASA Astrophysics Data System (ADS)

Wu, Renguang; Cao, Xi

2017-06-01

The present study contrasts interannual variations in the intensity of boreal summer 10-20-day and 30-60-day intraseasonal oscillations (ISOs) over the tropical western North Pacific and their factors. A pronounced difference is found in the relationship of the two ISOs to El Niño-Southern Oscillation. The 10-20-day ISO intensity is enhanced during El Niño developing summer, whereas the 30-60-day ISO intensity is enhanced during La Niña decaying summer. The above different relationship is interpreted as follows. The equatorial central and eastern Pacific SST anomalies modify vertical wind shear, lower-level moisture, and vertical motion in a southeast-northwest oriented band from the equatorial western Pacific to the tropical western North Pacific where the 10-20-day ISOs originate and propagate. These background field changes modulate the amplitude of 10-20-day ISOs. Preceding equatorial central and eastern Pacific SST anomalies induce SST anomalies in the North Indian Ocean in summer, which in turn modify vertical wind shear and vertical motion over the tropical western North Pacific. The modified background fields influence the amplitude of the 30-60-day ISOs when they reach the tropical western North Pacific from the equatorial region. A feedback of ISO intensity on local SST change is identified in the tropical western North Pacific likely due to a net effect of ISOs on surface heat flux anomalies. This feedback is more prominent from the 10-20-day than the 30-60-day ISO intensity change.

An ab initio study of Cu-based delafossites as an alternative to nickel oxide in photocathodes: effects of Mg-doping and surface electronic features.

PubMed

Schiavo, Eduardo; Latouche, Camille; Barone, Vincenzo; Crescenzi, Orlando; Muñoz-García, Ana B; Pavone, Michele

2018-05-23

CuMO2 delafossites (M = Al, Ga, and Cr) are p-type semiconductor oxides that have been recently proposed as the electrode in p-type dye-sensitized solar cells (p-DSSC) which is an alternative to the standard, low-performing nickel oxide. To assess this potential application of delafossites, we report here a DFT-based investigation of the structural and electronic properties of CuAlO2, CuGaO2 and CuCrO2. In particular, we address the role of Mg doping to obtain the p-type semiconducting character: the substitution of an M3+ cation with Mg2+ is easier with Ga than with Al and Cr, and, in all cases, the hole introduced by Mg2+ leads to the formation of Cu2+ species. Moreover, we address surface electronic features in order to characterize the most exposed delafossite surface termination and, more importantly, to predict the valence band maximum energy value, which determines the p-DSSC open circuit potential. From analysis of all our results, CuGaO2 emerges as the most promising system that can boost the development of new photocathodes for p-DSSCs.

Electrochemical study of ricin at glassy carbon electrode.

PubMed

Ribeiro, Williame F; da Costa, Daniel J E; Lourenço, Anabel S; Lopes, Ilanna C; de Medeiros, Everaldo P; Salazar-Banda, Giancarlo R; do Nascimento, Valberes B; de Araújo, Mário C U

2013-08-21

Ricin, Ricinus communis agglutinin 60 - RCA 60, is a deadly phytotoxic protein which inhibits ribosomes (class II), and there is no known effective antidote in living organisms. Ricin is composed of two polypeptide chains, A and B, linked covalently by a single disulfide bond. The analytical methods for the detection of RCA 60 are commonly laborious, expensive, require skilled labor, and involve sophisticated equipment. Aimed at the development of electroanalytical methods for RCA 60 detection, here we studied the electrochemical oxidation of RCA 60 on a glassy carbon (GC) electrode over a wide pH range, using cyclic voltammetry, differential pulse voltammetry (DPV) and square wave voltammetry (SWV). Two quasi-reversible electrochemical RCA 60 oxidation peaks were identified on the GC electrode by SWV. For values of 2.2 ≤ pH ≤ 10.2, DPV studies revealed that the peak potentials, EP1 and EP2, display a linear dependence with pH and the reaction mechanism involves the transfer of 2H⁺/2e⁻ (peak 1) and 1H⁺/1e⁻ (peak 2). The first and second RCA 60 oxidation steps may correspond to the oxidation of cysteine and tyrosine-tryptophan residues, respectively. The oxidation product of the second RCA 60 oxidation step appears at 7.0 ≤ pH ≤ 11.8. For pH ≥ 10.2, both processes are pH independent, resulting in a pKa of ca. 10.2. A third RCA 60 oxidation peak only appears at acidic pH. RCA 60 samples extracted from different castor seed cultivars showed similar electrochemical behavior, enabling the implementation of an analytical voltammetric method.

Influence of copper composition on mechanical properties of biodegradable material Mg-Zn-Cu for orthopedic application

NASA Astrophysics Data System (ADS)

Purniawan, A.; Maulidiah, H. M.; Purwaningsih, H.

2018-04-01

Implant is usually used as a treatment of bone fracture. At the moment, non-biodegradable implants is still widely employed in this application. Non-biodegradable implant requires re-surgery to retrieve implants that are installed in the body. It increase the cost and it is painful for the patient itself. In order to solve the problem, Mg-based biodegradable metals is developing so that the material will be compatible with body and gradually degrade in patient's body. However, magnesium has several disadvantages such as high degradation rates and low mechanical properties when compared to the mechanical properties of natural bone. Therefore, it is necessary to add elements into the magnesium alloy. In this research, copper (Cu) was alloyed in Mg alloy based biodegradable material. In addition, Cu is not only strengthening the structure but also for supporting element for the immune system, antibacterial and antifungal. The purpose of this research is to improve mechanical properties of Mg-based biodegradable material using Cu alloying. Powder metallurgy method was used to fabricate the device. The variation used in this research is the composition of Cu (0.5, 1, and 1.5% Cu). The porosity test was performed using apparent porosity test, compressive test and hardness test to know the mechanical properties of the alloy, and the weightless test to find out the material degradation rate. Based on the results can be conclude that Mg-Zn-Cu alloy material with 1% Cu composition is the most suitable specimen to be applied as a candidate for orthopedic devices material with hardness value is 393.6 MPa. Also obtained the value of the compressive test is 153 MPa.

Cu-releasing bioactive glass/polycaprolactone coating on Mg with antibacterial and anticorrosive properties for bone tissue engineering.

PubMed

Yang, Yuyun; Zheng, Kai; Liang, Ruifang; Mainka, Astrid; Taccardi, Nicola; Roether, Judith A; Detsch, Rainer; Goldmann, Wolfgang H; Virtanen, Sannakaisa; Boccaccini, Aldo R

2017-10-26

Bioactive glass nanoparticles containing copper (Cu-BGNs) were introduced into polycaprolactone (PCL) coating systems to improve the bioactivity, antibacterial properties, and corrosion resistance of vulnerable magnesium matrices under physiological conditions. The influence of different amounts of Cu-BGNs in PCL coatings was thoroughly investigated in determining the wettability, electrochemical properties, and antibacterial effects against Staphylococcus carnosus and Escherichia coli, as well as their cyto-compatibility. Cu-BGNs were observed randomly scattered in PCL coatings. Increasing the concentration of Cu-BGNs resulted in a slight decrease of the water contact angle, and a reduction in anticorrosion properties of the Cu-BGN composite coatings. Yet higher Cu-BGN content in coatings led to more calcium phosphate formation on the surface after 7 days of immersion in Dulbecco's modified Eagle's medium, which was confirmed by Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy. The growth of S. carnosus and E. coli was inhibited by Cu 2+ ions released from the Cu-BGN coatings. In addition, both direct and indirect cyto-compatibility experiments showed that the viability and proliferation of MG-63 cells on Cu-BGN coatings were highly increased compared to pure magnesium; however, an additional increase of Cu-BGN concentration showed a slight decrease of cell proliferation and cell activity. In summary, Cu-BGN/PCL composite coatings impart magnesium-based biomaterials with antibacterial and anticorrosive properties for clinical applications.

Dielectric Study of the Phase Transitions in [P(CH3)4]2CuY4 (Y = Cl, Br)

NASA Astrophysics Data System (ADS)

Gesi, Kazuo

2002-05-01

Phase transitions in [P(CH3)4]2CuY4 (Y = Cl, Br) have been studied by dielectric measurements. In [P(CH3)4]2CuCl4, a slight break and a discontinuous jump on the dielectric constant vs. temperature curve are seen at the normal-incommensurate and the incommensurate-commensurate phase transitions, respectively. A small peak of dielectric constant along the b-direction exists just above the incommensurate-to-commensurate transition temperature. The anisotropic dielectric anomalies of [P(CH3)4]2CuBr4 at phase transitions were measured along the three crystallographic axes. The pressure-temperature phase diagram of [P(CH3)4]2CuCl4 was determined. The initial pressure coefficients of the normal-to-incommensurate and the incommensurate-to-commensurate transition temperatures are 0.19 K/MPa and 0.27 K/MPa, respectively. The incommensurate phase in [P(CH3)4]2CuCl4 disappears at a triple point which exists at 335 MPa and 443 K. The stability and the pressure effects of the incommensurate phases are much different among the four [Z(CH3)4]2CuY4 crystals (Z = N, P; Y = Cl, Br).

Esomeprazole 40 mg provides improved intragastric acid control as compared with lansoprazole 30 mg and rabeprazole 20 mg in healthy volunteers.

PubMed

Wilder-Smith, Clive H; Röhss, Kerstin; Nilsson-Pieschl, Catharina; Junghard, Ola; Nyman, Lars

2003-01-01

To compare the effects of standard-dose esomeprazole with those of standard doses of lansoprazole and rabeprazole on intragastric pH during repeated daily oral dosing in healthy volunteers. In two standardized, randomized crossover studies, Helicobacter pylori negative healthy volunteers (study A: 19 males, 5 females; study B: 13 males, 10 females) received esomeprazole 40 mg and either lansoprazole 30 mg (study A) or rabeprazole 20 mg (study B) orally once daily in the morning for 5 days. Continuous 24-hour intragastric pH recording was performed on day 5. The intragastric pH was maintained >4 for 65% (95% CI 59.5-71.3) of the 24-hour period with esomeprazole and for 53% of the time (95% CI 47.0-58.9) with lansoprazole in study A (p < 0.001). In study B, the proportion of time with pH >4 was 61% (95% CI 53.6-68.3) with esomeprazole versus 45% (95% CI 37.7-52.5) with rabeprazole (p = 0.005). The 24-hour median pH and the proportion of volunteers with intragastric pH >4 for > or =12 h and > or =16 h were significantly higher with esomeprazole than with either lansoprazole or rabeprazole. Esomeprazole 40 mg provides significantly more effective and more sustained gastric acid control than lansoprazole 30 mg or rabeprazole 20 mg in healthy volunteers. Copyright 2003 S. Karger AG, Basel

Liquidus Diagram of the Ba-Y-Cu-O System in the Vicinity of the Ba2YCu3O6+x Phase Field

PubMed Central

Wong-Ng, Winnie; Cook, Lawrence P.

1998-01-01

This paper describes the melting equilibria in the vicinity of the high Tc phase Ba2YCu3O6+x, including evidence for two Ba-Y-Cu-O immiscible liquids. Melting equilibria have been investigated in purified air using a combination of differential thermal analysis (DTA), thermogravimetric analysis (TGA), powder x-ray diffraction (XRD), MgO wick entrapment of liquid for analysis, scanning electron microscopy (SEM) coupled with energy dispersive x-ray analysis (EDS), and hydrogen reduction for determination of copper oxidation state. For relatively barium-rich compositions, it was necessary to prepare the starting materials under controlled atmosphere conditions using BaO. A liquidus diagram was derived from quantitative data for the melts involved in various melting reactions. In general the 1/2(Y2O3) contents of the melts participating in these equilibria were low (mole fraction <4 %). The primary phase field of Ba2YCu3O6+x occurs at a mole fraction of <2.0 % 1/2Y2O3 and lies very close along the BaO-CuOx edge, extending from a mole fraction of ≈43 % CuO to a mole fraction of ≈76 % CuO. It is divided by a liquid miscibility gap and extends on either side about this gap. The topological sequence of melting reactions associated with the liquidus is presented as a function of temperature. Implications for the growth of Ba2YCu3O6+x crystals are discussed. PMID:28009382

Multi-scale Investigation on Microstructure, Mechanical Properties, and Deformation Mechanisms in Mg Alloys

NASA Astrophysics Data System (ADS)

Zhang, Dalong

Mg and its alloys are promising candidates for light-weight structural applications, e.g., aircraft, automobile, electronic, etc. However, the inherent hexagonal close packed crystal structure makes the deformation of Mg anisotropic, namely deformation only occurs predominantly by dislocation slip in the close-packed (0001) plane (i.e., basal plane), or by deformation twinning in {101¯2} planes. Both basal slip and twinning cause the crystal to re-orient. Consequently, polycrystalline Mg alloys that have undergone thermomechanical processing usually contain strong texture, i.e., preferred crystallographic orientation in grains. The texture in turn leads to anisotropic deformation in wrought Mg alloys. For example, in extruded Mg alloys, the compressive yield strength is usually much lower than the tensile yield strength (so-called yield asymmetry and strength differential). It is the anisotropy that hinders the broader application of Mg alloys. Recent modeling studies on Mg predict that certain alloying elements, particularly rare-earth elements (e.g., Y, Ce, Nd, Gd, etc.), could alter the active deformation modes and enhance homogeneous deformation and overall mechanical properties in Mg. Therefore, the objective of this dissertation research is to investigate experimentally the effects of alloying element Y in reducing the intrinsic and extrinsic anisotropy, modifying texture, and enhancing the overall strength and ductility for Mg. In addition, the research also uncovered some unexpected "side effects" of Y and these phenomena were studied and explained from a fundamental perspective. The methodology used in this work is described as follows. Ultrafine grained Mg 2.5 at.% Y alloy (UFG Mg-2.5Y) was prepared by powder metallurgy method, including gas atomization for producing Mg-2.5Y powder, degassing and hot isostatic pressing (HIP), and hot extrusion. Both the as-HIPed and the as-extruded materials were characterized by electron back-scattered diffraction (EBSD

Monte Carlo study of backscattering of. beta. rays from various monoatomic slabs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandey, L. N.; Rustgi, M. L.

1989-07-01

A Monte Carlo study of the backscattering coefficients and backscatteringintensity of ..beta.. rays from /sup 204/ Tl and /sup 90/ Y sources from slabs of Al,Cu, Sn, Tb, and Pb of different thicknesses is carried out. The results forangles of incidence 0/degree/, 30/degree/, 45/degree/, and 60/degree/ and absorber thicknesses of 3,5, 10, 15, 30, and 50 mg/cm/sup 2/ for /sup 204/ Tl ..beta.. rays and thicknesses of3, 5, 10, 20, 50, 100, 150, and 190 mg/cm/sup 2/ for /sup 90/ Y ..beta.. rays aregiven in tabular form. On using normalization factors good agreement with themeasurements of Sharma and Singh ismore » obtained. A phenomenological attempt toinvestigate a relationship between the backscatter intensity and atomic number/ital Z/ of the backscatterer indicates that the backscattered intensity is alinear function of ln /ital Z/(/ital Z/+1). A partial theoretical justification forthis relationship is given.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vincent, S.; Daiwile, A.; Devi, S. S.

Metallic glasses are a potential and compatible implant candidate for biomedical applications. In the present investigation, a comparative study between novel Zr 55Co 30Ti 15 and Cu 60Zr 20Ti 20 metallic glasses is carried out to evaluate in vitro biocompatibility using simulated body fluids. The bio-corrosion behavior of Zr- and Cu-based metallic glasses in different types of artificial body fluids such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hank’s balanced saline solution is evaluated using potentiodynamic polarization studies at a constant body temperature of 310.15 K (37 °C). Surface morphology of samples after bio-corrosion experimentsmore » was observed by scanning electron microscopy. In vitro cytotoxicity test on glassy alloys were performed using human osteosarcoma cell line as per 10993-5 guidelines from International Organization for Standardization. As a result, the comparative study between Zr- and Cu-based glassy alloys provides vital information about the effect of elemental composition on biocompatibility of metallic glasses.« less

41 CFR 60-30.29 - Record.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Record. 60-30.29 Section... 11246 Post-Hearing Procedures § 60-30.29 Record. After expiration of the time for filing briefs and..., which shall be the final Administrative order, on the basis of the record. The record shall consist of...

41 CFR 60-30.29 - Record.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Record. 60-30.29 Section... 11246 Post-Hearing Procedures § 60-30.29 Record. After expiration of the time for filing briefs and..., which shall be the final Administrative order, on the basis of the record. The record shall consist of...

41 CFR 60-30.29 - Record.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Record. 60-30.29 Section... 11246 Post-Hearing Procedures § 60-30.29 Record. After expiration of the time for filing briefs and..., which shall be the final Administrative order, on the basis of the record. The record shall consist of...

41 CFR 60-30.29 - Record.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Record. 60-30.29 Section... 11246 Post-Hearing Procedures § 60-30.29 Record. After expiration of the time for filing briefs and..., which shall be the final Administrative order, on the basis of the record. The record shall consist of...

Strain localization parameters of AlCu4MgSi processed by high-energy electron beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lunev, A. G., E-mail: agl@ispms.ru; Nadezhkin, M. V., E-mail: mvn@ispms.ru; National Research Tomsk Polytechnic University, Tomsk, 634050

2015-10-27

The influence of the electron beam surface treatment of AlCu4MgSi on the strain localization parameters and on the critical strain value of the Portevin–Le Chatelier effect has been considered. The strain localization parameters were measured using speckle imaging of the specimens subjected to the constant strain rate uniaxial tension at a room temperature. Impact of the surface treatment on the Portevin–Le Chatelier effect has been investigated.

Biosorption of Cu2+ and Pb2+ using sophora alopecuroides residue

NASA Astrophysics Data System (ADS)

Feng, N.; Fan, W.; Zhu, M.; Zhang, Y.

2016-08-01

Sophora alopecuroides residue (SAP), a kind of traditional Chinese herbal medicine residue, was developed in an alternative biosorbent for the removal Cu2+ and Pb2+ in simulated wastewater. The morphology and surface texture of SAP were characterized by scanning electron microscopy, which showed a loose and porous structure. The biosorption experiments of Cu2+ and Pb2+ onto SAP were investigated by using batch techniques. High biosorption percentage appeared at pH values of 4.5-6.0. The experimental data followed the second-order kinetic model well. Equilibrium fit with the Langmuir isotherm model well. The maximum biosorption capacity of an adsorbent at 25 °C was respectively 60.6 mg/g Cu2+ and 128.1 mg/g Pb2+. The findings of the present study show that SAP is an attractive and effective biosorbent for Cu2+ and Pb2+.

41 CFR 60-30.27 - Recommended decision.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Recommended decision. 60-30.27 Section 60-30.27 Public Contracts and Property Management Other Provisions Relating to Public... 30-RULES OF PRACTICE FOR ADMINISTRATIVE PROCEEDINGS TO ENFORCE EQUAL OPPORTUNITY UNDER EXECUTIVE...

41 CFR 60-30.27 - Recommended decision.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Recommended decision. 60-30.27 Section 60-30.27 Public Contracts and Property Management Other Provisions Relating to Public... 30-RULES OF PRACTICE FOR ADMINISTRATIVE PROCEEDINGS TO ENFORCE EQUAL OPPORTUNITY UNDER EXECUTIVE...

41 CFR 60-30.27 - Recommended decision.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Recommended decision. 60-30.27 Section 60-30.27 Public Contracts and Property Management Other Provisions Relating to Public... 30-RULES OF PRACTICE FOR ADMINISTRATIVE PROCEEDINGS TO ENFORCE EQUAL OPPORTUNITY UNDER EXECUTIVE...

41 CFR 60-30.27 - Recommended decision.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Recommended decision. 60-30.27 Section 60-30.27 Public Contracts and Property Management Other Provisions Relating to Public... 30-RULES OF PRACTICE FOR ADMINISTRATIVE PROCEEDINGS TO ENFORCE EQUAL OPPORTUNITY UNDER EXECUTIVE...

41 CFR 60-30.27 - Recommended decision.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Recommended decision. 60-30.27 Section 60-30.27 Public Contracts and Property Management Other Provisions Relating to Public... 30-RULES OF PRACTICE FOR ADMINISTRATIVE PROCEEDINGS TO ENFORCE EQUAL OPPORTUNITY UNDER EXECUTIVE...

CuY zeolite catalysts prepared by ultrasonication-assisted ion-exchange for oxidative carbonylation of methanol to dimethyl carbonate.

PubMed

Woo, Je-Min; Seo, Jung Yoon; Kim, Hyunuk; Lee, Dong-Ho; Park, Young Cheol; Yi, Chang-Keun; Park, Yeong Seong; Moon, Jong-Ho

2018-06-01

The influence of ultrasonication treatment on the catalytic performance of CuY zeolite catalysts was investigated for the liquid-phase oxidative carbonylation of methanol to dimethyl carbonate (DMC). The deammoniation method of NH 4 Y into HY zeolites was optimized and characterized by elemental analyzer, derivative thermogravimetry, Brunauer-Emmett-Teller (BET) analyzer, and powder X-ray diffractometry, revealing that the HY zeolite deammoniated at 400 °C presented the highest surface area, complete ammonium/proton ion exchange, and no structure collapse, rendering it the best support from all the prepared zeolites. CuY zeolites were prepared via aqueous phase ion exchange with the aid of ultrasonication. Upon ultrasonication, the Cu + active centers were uniformly dispersed in the Y zeolites, penetrating the core of the zeolite particles in a very short time. In addition to enhancing the Cu dispersity, the ultrasonication treatment influenced the BET surface area, acid amount, Cu + /Cu 2+ ratio, and also had a relatively small impact on the Cu loading. Consequently, adequate exposure to ultrasonication was able to increase the conversion rate of methanol into dimethyl carbonate up to 11.4% with a comparable DMC selectivity of 23.7%. This methanol conversion is 2.65 times higher than that obtained without the ultrasonication treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Fiber Laser Welding-Brazing Characteristics of Dissimilar Metals AZ31B Mg Alloys to Copper with Mg-Based Filler

NASA Astrophysics Data System (ADS)

Zhao, Xiaoye; Tan, Caiwang; Meng, Shenghao; Chen, Bo; Song, Xiaoguo; Li, Liqun; Feng, Jicai

2018-03-01

Fiber laser welding-brazing of 1-mm-thick AZ31B Mg alloys to 1.5-mm-thick copper (T2) with Mg-based filler was performed in a lap configuration. The weld appearance, interfacial microstructure and mechanical properties were investigated with different heat inputs. The results indicated that processing windows for optimizing appropriate welding parameters were relatively narrow in this case. Visually acceptable joints with certain strength were achieved at appropriate welding parameters. The maximum tensile-shear fracture load of laser-welded-brazed Mg/Cu joint could reach 1730 N at the laser power of 1200 W, representing 64.1% joint efficiency relative to AZ31Mg base metal. The eutectic structure (α-Mg + Mg2Cu) and Mg-Cu intermetallic compound was observed at the Mg/Cu interface, and Mg-Al-Cu ternary intermetallic compound were identified between intermetallics and eutectic structure at high heat input. All the joints fractured at the Mg-Cu interface. However, the fracture mode was found to differ. For laser power of 1200 W, the surface was characterized by tearing edge, while that with poor joint strength was almost dominated by smooth surface or flat tear pattern.

Crystal nucleation in amorphous (Au/100-y/Cu/y/)77Si9Ge14 alloys

NASA Technical Reports Server (NTRS)

Thompson, C. V.; Greer, A. L.; Spaepen, F.

1983-01-01

Because, unlike most metallic glasses, melt-spun alloys of the series (Au/100-y/Cu/y/)77Si9Ge14 exhibit well separated glass transition and kinetic crystallization temperatures, crystallization can be studied in the fully relaxed amorphous phase. An isothermal calorimetric analysis of the devitrification kinetics of the amorphous alloy indicates sporadic nucleation and a constant growth rate. It is found for the cases of alloys with y values lower than 25 that the classical theory of homogeneous nucleation is consistent with observations, including transient effects. An analysis of the crystallization kinetics shows that slow crystal growth rates play an important role in glass formation in these alloys. Although the reduced glass transition temperature increases with Cu content, glass formation is more difficult at high Cu contents, perhaps because of a difference in nucleus composition.

Auto-combustion synthesis and characterization of Mg doped CuAlO{sub 2} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, Shraddha, E-mail: shraddhaa32@gmail.com; Parveen, Azra; Naqvi, A. H.

2015-06-24

The synthesis of pure and Mg doped Copper aluminumoxide CuAlO{sub 2}nanoparticles, a promising p-type TCO (transparent conducting oxide) have been done bysol gel auto combustion method using NaOH as a fuel, calcinated at 600°C. The structural properties were examined by XRD and SEM techniques. The optical absorption spectra of CuAlO{sub 2} sample recorded by UV-VIS spectrophotometer in the range of 200 to 800 nm have been presented. The crystallite size was determined by powder X-ray diffraction technique. The electrical behavior of pure and Mg doped CuAlO{sub 2} has been studied over a wide range of frequencies by using complex impedance spectroscopy.Themore » variation of a.c. conductivity has been studied as function of frequency and temperature. The data taken together conclude that doping causes decreases in the ac conductivity of the nanoparticles as compared with the pure nanoparticles. Mg doping affects the optical properties and band gap.« less

FADING EFFECT OF LiF:Mg,Ti AND LiF:Mg,Cu,P Ext-Rad AND WHOLE-BODY DETECTORS.

PubMed

Pereira, J; Pereira, M F; Rangel, S; Saraiva, M; Santos, L M; Cardoso, J V; Alves, J G

2016-09-01

Thermoluminescence dosemeters are widely used in individual and environmental monitoring. The aim of this work was to compare the thermal stability of dosemeters of the Ext-Rad and whole-body card types with LiF:Mg,Ti and LiF:Mg,Cu,P detectors stored at different temperatures and periods. The dosemeters were stored at 0°C, room temperature and 40°C for periods that lasted 8, 30, 45, 90 and 120 d. In general, TLD-100H detectors present higher TL signal stability than TLD-100 detectors. The intensity of the signal remained constant for both materials for storage periods at 0°C. At RT the same results was observed for TLD-100H. For TLD-100 detectors, a maximum variation of 22 % was registered for the longest period. At 40°C the TL signal decreased with storage time for both detectors. The TL signal of TLD-100H detectors presented maximum variations of 12 % whereas for TLD-100 detectors, larger variations of 25 % were observed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Improvement of persistent magnetic field trapping in bulk Y-Ba-Cu-O superconductors

NASA Technical Reports Server (NTRS)

Chen, In-Gann; Weinstein, Roy

1993-01-01

For type-II superconductors, magnetic field can be trapped due to persistent internal supercurrent. Quasi-persistent magnetic fields near 2 T at 60 K (and 1.4 T at 77 K) have been measured in minimagnets made of proton-irradiated melt-textured Y-Ba-Cu-O (MT-Y123) samples. Using the trapping effect, high-field permanent magnets with dipole, quadrupole, or more complicated configurations can be made of existing MT-Y123 material, thus bypassing the need for high-temperature superconductor (HTS) wires. A phenomenological current model has been developed to account for the trapped field intensity and profile in HTS samples. This model is also a guide to select directions of materials development to further improve field trapping properties. General properties such as magnetic field intensities, spatial distributions, stabilities, and temperature dependence of trapped field are discussed.

Characterization of Cu buffer layers for growth of L10-FeNi thin films

NASA Astrophysics Data System (ADS)

Mizuguchi, M.; Sekiya, S.; Takanashi, K.

2010-05-01

A Cu(001) layer was fabricated on a Au(001) layer to investigate the use of Cu as a buffer layer for growing L10-FeNi thin films. The epitaxial growth of a Cu buffer layer was observed using reflection high-energy electron diffraction. The flatness of the layer improved drastically with an increase in the substrate temperature although the layer was an alloy (AuCu3). An FeNi thin film was epitaxially grown on the AuCu3 buffer layer by alternate monatomic layer deposition and the formation of an L10-FeNi ordered alloy was expected. The AuCu3 buffer layer is thus a promising candidate material for the growth of L10-FeNi thin films.

Highly charged swelling mica reduces Cu bioavailability in Cu-contaminated soils.

PubMed

Stuckey, Jason W; Neaman, Alexander; Ravella, Ramesh; Komarneni, Sridhar; Martínez, Carmen Enid

2009-01-01

This is the first test of a highly charged swelling mica's (Na-2-mica) ability to reduce the plant-absorbed Cu in Cu-contaminated soils from Chile. Perennial ryegrass (Lolium perenne L.) was grown in two acid soils (Sector 2: pH 4.2, total Cu = 172 mg Cu kg(-1) and Sector 3: pH 4.2, total Cu = 112 mg Cu kg(-1)) amended with 0.5% and 1% (w/w) mica, and 1% (w/w) montmorillonite. At 10 weeks of growth, both mica treatments decreased the shoot Cu of ryegrass grown in Sector 2 producing shoot Cu concentrations above 21-22 mg Cu kg(-1) (the phytotoxicity threshold for that species), yet the mica treatments did not reduce shoot Cu concentrations when grown in Sector 3, which were at a typical level. The mica treatments improved shoot growth in Sector 3 by reducing free and extractable Cu to low enough levels where other nutrients could compete for plant absorption and translocation. In addition, the mica treatments improved root growth in both soils, and the 1% mica treatment reduced root Cu in both soils. This swelling mica warrants further testing of its ability to assist re-vegetation and reduce Cu bioavailability in Cu-contaminated surface soils.

Comparison of Mg-based multilayers for solar He II radiation at 30.4 nm wavelength

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu Jingtao; Zhou Sika; Li Haochuan

2010-07-10

Mg-based multilayers, including SiC/Mg, Co/Mg, B4C/Mg, and Si/Mg, are investigated for solar imaging and a He II calibration lamp at a 30.4 nm wavelength. These multilayers were fabricated by a magnetron sputtering method and characterized by x-ray reflection. The reflectivities of these multilayers were measured by synchrotron radiation. Near-normal-incidence reflectivities of Co/Mg and SiC/Mg multilayer mirrors are as high as 40.3% and 44.6%, respectively, while those of B4C/Mg and Si/Mg mirrors are too low for application. The measured results suggest that SiC/Mg, Co/Mg multilayers are promising for a 30.4 nm wavelength.

Effect of silicon on wheat seedlings (Triticum turgidum L.) grown in hydroponics and exposed to 0 to 30 µM Cu.

PubMed

Keller, C; Rizwan, M; Davidian, J-C; Pokrovsky, O S; Bovet, N; Chaurand, P; Meunier, J-D

2015-04-01

Aqueous Si limits Cu uptake by a Si-accumulating plant via physicochemical mechanisms occurring at the root level. Sufficient Si supply may alleviate Cu toxicity in Cu-contaminated soils. Little information is available on the role of silicon (Si) in copper (Cu) tolerance while Cu toxicity is widespread in crops grown on Cu-contaminated soils. A hydroponic study was set up to investigate the influence of Si on Cu tolerance in durum wheat (Triticum turgidum L.) grown in 0, 0.7, 7.0 and 30 µM Cu without and with 1.0 mM Si, and to identify the mechanisms involved in mitigation of Cu toxicity. Si supply alleviated Cu toxicity in durum wheat at 30 µM Cu, while Cu significantly increased Si concentration in roots. Root length, photosynthetic pigments concentrations, macroelements, and organic anions (malate, acetate and aconitate) in roots, were also increased. Desorption experiments, XPS analysis of the outer thin root surface (≤100 Å) and µXRF analyses showed that Si increased adsorption of Cu at the root surface as well as Cu accumulation in the epidermis while Cu was localised in the central cylinder when Si was not applied. Copper was not detected in phytoliths. This study provides evidences for Si-mediated alleviation of Cu toxicity in durum wheat. It also shows that Si supplementation to plants exposed to increasing levels of Cu in solution induces non-simultaneous changes in physiological parameters. We propose a three-step mechanism occurring mainly at the root level and limiting Cu uptake and translocation to shoots: (i) increased Cu adsorption onto the outer thin layer root surface and immobilisation in the vicinity of root epidermis, (ii) increased Cu complexation by both inorganic and organic anions such as aconitate and, (iii) limitation of translocation through an enhanced thickening of a Si-loaded endodermis.

The Electrochemical Co-reduction of Mg-Al-Y Alloys in the LiCl-NaCl-MgCl2-AlF3-YCl3 Melts

NASA Astrophysics Data System (ADS)

Li, Mei; Liu, Yaochen; Han, Wei; Wang, Shanshan; Zhang, Milin; Yan, Yongde; Shi, Weiqun

2015-04-01

The electrochemical formation of Mg-Al-Y alloys was studied in the LiCl-NaCl-MgCl2 melts by the addition of AlF3 and YCl3 on a molybdenum electrode at 973 K (700 °C). In order to reduce the volatilization of salt solvent in the electrolysis process, the volatile loss of LiCl-NaCl-MgCl2 and LiCl-KCl-MgCl2 melts was first measured in the temperature range from 873 K to 1023 K (600 °C to 750 °C). Then, the electrochemical behaviors of Mg(II), Al(III), Y(III) ions and alloy formation processes were investigated by cyclic voltammetry, chronopotentiometry, and open circuit chronopotentiometry. The cyclic voltammograms indicate that the under-potential deposition of magnesium and yttrium on pre-deposited Al leads to formation of Mg-Al and Al-Y intermetallic compounds. The Mg-Al-Y alloys were prepared by galvanostatic electrolysis in the LiCl-NaCl-MgCl2-AlF3-YCl3 melts and characterized by X-ray diffraction and scanning electron microscopy with energy dispersive spectrometry. Composition of the alloys was analyzed by inductively coupled plasma-atomic emission spectrometer, and current efficiency was also determined by the alloy composition.

Dependence of magnetic anisotropy on MgO sputtering pressure in Co20Fe60B20/MgO stacks

NASA Astrophysics Data System (ADS)

Kaidatzis, A.; Serletis, C.; Niarchos, D.

2017-10-01

We investigated the dependence of magnetic anisotropy of Ta/Co20Fe60B20/MgO stacks on the Ar partial pressure during MgO deposition, in the range between 0.5 and 15 mTorr. The stacks are studied before and after annealing at 300°C and it is shown that magnetic anisotropy significantly depends on Ar partial pressure. High pressure results in stacks with very low perpendicular magnetic anisotropy even after annealing, while low pressure results in stacks with perpendicular anisotropy even at the as-deposited state. A monotonic increase of magnetic anisotropy energy is observed as Ar partial pressure is decreased.

41 CFR 60-30.20 - Ex parte communications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Ex parte communications. 60-30.20 Section 60-30.20 Public Contracts and Property Management Other Provisions Relating to... EXECUTIVE ORDER 11246 Hearings and Related Matters § 60-30.20 Ex parte communications. The Administrative...

41 CFR 60-30.20 - Ex parte communications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Ex parte communications. 60-30.20 Section 60-30.20 Public Contracts and Property Management Other Provisions Relating to... EXECUTIVE ORDER 11246 Hearings and Related Matters § 60-30.20 Ex parte communications. The Administrative...

Structure dependent electrical properties of Ni-Mg-Cu nano ferrites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhari, Nagabhushan J., E-mail: nagabhushanchoudhari@gmail.com; Kakati, Sushanth S.; Hiremath, Chidanandayya S.

2016-05-06

Nano ferrites with the general chemical formula Ni{sub 0.5}Mg{sub x}Cu{sub 1-x} Fe{sub 2}O{sub 4} were synthesized by chemical route. They were characterized by x-ray diffraction by powder method. The diffraction patterns confirm the formation of single phase ferrites. The particle size is calculated by Scherrer formula which varies between 20nm to 60nm. DC resistivity was measured as a function of composition from room temperature to 700{sup o} C by two probe method. These ferrites show higher resistivity than those synthesized by ceramic method, due to control over composition and morphology. This leads to the elimination of domain wall resonance somore » that the materials can work at higher frequencies. AC resistivity was measured as a function of frequency at room temperature. Dielectric dispersion obeys Maxwell - Wagner model, in accordance with Koop’s phenomenological theory. The variation of loss angle follows the variation of ac resistivity with frequency and composition. The change in ac conductivity with frequency obeys the power law σ{sub a} = B.ω{sup n}. Such a behavior suggests that conductivity is due to polarons in all the samples.« less

Comparative study of electrical transport and magnetic measurements of Y3Ba5Cu8O18±δ and YBa2Cu3O7-δ compounds: intragranular and intergranular superconducting properties

NASA Astrophysics Data System (ADS)

Slimani, Y.; Hannachi, E.; Ben Salem, M. K.; Ben Azzouz, F.; Ben Salem, M.

2018-02-01

We compare the superconducting properties and flux pinning characteristics between YBa2Cu3O7-δ (called Y-123) and Y3Ba5Cu8O18±δ (called Y-358) compounds. Both samples were synthesized through the solid-state reaction. The samples were examined by X-ray diffraction, and scanning electron microscope coupled with energy dispersive spectrometry. The critical current densities of the prepared samples were investigated using current-voltage, magnetization measurements and ac-susceptibility. It is demonstrated that the Y-358 exhibits better superconducting and pinning properties than the Y-123 one. This may be ascribed to the layered structure and the occurrence of a greater number of insulating layers between the CuO2 planes that act as effective pinning sites and consequently conduce to a better fundamental pinning capacity in Y-358.

41 CFR 60-30.17 - Appearance of witnesses.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Appearance of witnesses. 60-30.17 Section 60-30.17 Public Contracts and Property Management Other Provisions Relating to... EXECUTIVE ORDER 11246 Hearings and Related Matters § 60-30.17 Appearance of witnesses. (a) A party wishing...

41 CFR 60-30.17 - Appearance of witnesses.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Appearance of witnesses. 60-30.17 Section 60-30.17 Public Contracts and Property Management Other Provisions Relating to... EXECUTIVE ORDER 11246 Hearings and Related Matters § 60-30.17 Appearance of witnesses. (a) A party wishing...

In situ AFM investigation of slow crack propagation mechanisms in a glassy polymer

NASA Astrophysics Data System (ADS)

George, M.; Nziakou, Y.; Goerke, S.; Genix, A.-C.; Bresson, B.; Roux, S.; Delacroix, H.; Halary, J.-L.; Ciccotti, M.

2018-03-01

A novel experimental technique based on in situ AFM monitoring of the mechanisms of damage and the strain fields associated to the slow steady-state propagation of a fracture in glassy polymers is presented. This micron-scale investigation is complemented by optical measurements of the sample deformation up to the millimetric macroscopic scale of the sample in order to assess the proper crack driving conditions. These multi-scale observations provide important insights towards the modeling of the fracture toughness of glassy polymers and its relationship with the macromolecular structure and non-linear rheological properties. This novel technique is first tested on a standard PMMA thermoplastic in order to both evaluate its performance and the richness of this new kind of observations. Although the fracture propagation in PMMA is well known to proceed through crazing in the bulk of the samples, our observations provide a clear description and quantitative evaluation of a change of fracture mechanism towards shear yielding fracture accompanied by local necking close to the free surface of the sample, which can be explained by the local change of stress triaxiality. Moreover, this primary surface necking mechanism is shown to be accompanied by a network of secondary grooves that can be related to surface crazes propagating towards the interior of the sample. This overall scenario is validated by post-mortem fractographic investigations by scanning electron microscopy.

Effect of severe plastic deformation on the structure and mechanical properties of Al-Cu-Mg alloy

NASA Astrophysics Data System (ADS)

Khafizova, E.; Islamgaliev, R.

2014-08-01

Aluminum Al-Cu-Mg alloy has been subjected to high pressure torsion (HPT) and equal-channel angular pressing (ECAP) at various temperatures. An ultrafine-grained (UFG) structure thermally stable up to a temperature of 175 °C was produced in all the investigated samples. Simultaneous increase in strength and ductility has been demonstrated in an ECAPed sample in comparison with a coarse-grained sample subjected to standard treatment.

Extraction method based on emulsion breaking for the determination of Cu, Fe and Pb in Brazilian automotive gasoline samples by high-resolution continuum source flame atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Leite, Clarice C.; de Jesus, Alexandre; Kolling, Leandro; Ferrão, Marco F.; Samios, Dimitrios; Silva, Márcia M.

2018-04-01

This work reports a new method for extraction of Cu, Fe and Pb from Brazilian automotive gasoline and their determination by high-resolution continuous source flame atomic absorption spectrometry (HR-CS FAAS). The method was based on the formation of water-in-oil emulsion by mixing 2.0 mL of extraction solution constituted by 12% (w/v) Triton X-100 and 5% (v/v) HNO3 with 10 mL of sample. After heating at 90 °C for 10 min, two well-defined phases were formed. The bottom phase (approximately 3.5 mL), composed of acidified water and part of the ethanol originally present in the gasoline sample, containing the extracted analytes was analyzed. The surfactant and HNO3 concentrations and the heating temperature employed in the process were optimized by Doehlert design, using a Brazilian gasoline sample spiked with Cu, Fe and Pb (organometallic compounds). The efficiency of extraction was investigated and it ranged from 80 to 89%. The calibration was accomplished by using matrix matching method. For this, the standards were obtained performing the same extraction procedure used for the sample, using emulsions obtained with a gasoline sample free of analytes and the addition of inorganic standards. Limits of detection obtained were 3.0, 5.0 and 14.0 μg L-1 for Cu, Fe and Pb, respectively. These limits were estimated for the original sample taking into account the preconcentration factor obtained. The accuracy of the proposed method was assured by recovery tests spiking the samples with organometallic standards and the obtained values ranged from 98 to 105%. Ten gasoline samples were analyzed and Fe was found in four samples (0.04-0.35 mg L-1) while Cu (0.28 mg L-1) and Pb (0.60 mg L-1) was found in just one sample.

41 CFR 60-30.18 - Rules of evidence.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Rules of evidence. 60-30.18 Section 60-30.18 Public Contracts and Property Management Other Provisions Relating to Public... ORDER 11246 Hearings and Related Matters § 60-30.18 Rules of evidence. In any hearing, decision, or...

41 CFR 60-30.18 - Rules of evidence.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Rules of evidence. 60-30.18 Section 60-30.18 Public Contracts and Property Management Other Provisions Relating to Public... ORDER 11246 Hearings and Related Matters § 60-30.18 Rules of evidence. In any hearing, decision, or...

Effects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects.

PubMed

Wilhelmus, Micha Mm; Hay, Justin L; Zuiker, Rob Gja; Okkerse, Pieter; Perdrieu, Christelle; Sauser, Julien; Beaumont, Maurice; Schmitt, Jeroen; van Gerven, Joop Ma; Silber, Beata Y

2017-02-01

Caffeine induces positive effects on sustained attention, although studies assessing the acute effects of low caffeine dose (<75 mg) on sustained attention are limited and use short-term tests. Therefore, we investigated the acute effects of a 60 mg dose of caffeine on sustained attention in tests lasting up to 45 minutes using 82 low or non-caffeine-consuming healthy male ( n=41) and female ( n=41) adults aged between 40 and 60 years. Vigilance was measured using Mackworth Clock test, Rapid Visual Information Processing Test, adaptive tracking test, saccadic eye movement and attention switch test. Effects on mood and fatigue were analysed using Bond and Lader and Caffeine Research visual analogue scales, and Samn-Perelli questionnaire. Saliva sampling was performed for both compliance and caffeine pharmacokinetic analysis. Administration of a 60 mg caffeine dose resulted in a significant improvement in sustained attention compared with the placebo. Also a significantly improved peak saccadic velocity and reaction time performance was found, and decreased error rate. Significantly increased feelings of alertness, contentment and overall mood after caffeine treatment compared with placebo were observed. This study demonstrated that in healthy adult subjects oral administration of a single 60 mg caffeine dose elicited a clear enhancement of sustained attention and alertness, measured both in multiple objective performances and in subjective scales.

Biosorption of heavy metal copper (Cu2+) by Saccharomyces cerevisiae

NASA Astrophysics Data System (ADS)

Ririhena, S. A. J.; Astuti, A. D.; Fachrul, M. F.; Silalahi, M. D. S.; Hadisoebroto, R.; Rinanti, A.

2018-01-01

This research aims to study the optimum effect of contact time and pH adsorption of copper (Cu2+) from electroplating industry waste by dried beer waste S.cerevisiae. This research conducted using batch culture with pH variation 2,3,4,5, and 6, contact time variation 60, 90, 120, 150, 180 minutes, 150 rpm at room temperature (± 28°C), initial Cu2+ concentration 33,746 mg/l, and biosorbent mass 200 mg & 500 mg. The adsorption of heavy metal ions Cu2+ occurs in all variations of pH and contact time at optimum pH. The optimum adsorption occurs at pH 4 with contact time 120 minutes for both 200 mg (41.60%) and 500 mg (61.04%) beer waste biosorbent. Cell morphology seen with Scanning Electron Microscope (SEM) analysis shows the change of cell wall that gets damaged from Cu2+ adsorption. It also proved by the decreased concentration of initial high concentration carboxyl groups. The adsorption process of this research complies to Freundlich Isotherm with R2 value closest to 1 and followed first order kinetic.

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

NASA Astrophysics Data System (ADS)

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.

Hot Deformation and Dynamic Recrystallization Behavior of the Cu-Cr-Zr-Y Alloy

NASA Astrophysics Data System (ADS)

Zhang, Yi; Huili, Sun; Volinsky, Alex A.; Tian, Baohong; Chai, Zhe; Liu, Ping; Liu, Yong

2016-03-01

To study the workability and to optimize the hot deformation processing parameters of the Cu-Cr-Zr-Y alloy, the strain hardening effect and dynamic softening behavior of the Cu-Cr-Zr-Y alloy were investigated. The flow stress increases with the strain rate and stress decreases with deformation temperature. The critical conditions, including the critical strain and stress for the occurrence of dynamic recrystallization, were determined based on the alloy strain hardening rate. The critical stress related to the onset of dynamic recrystallization decreases with temperature. The evolution of DRX microstructure strongly depends on the deformation temperature and the strain rate. Dynamic recrystallization appears at high temperatures and low strain rates. The addition of Y can refine the grain and effectively accelerate dynamic recrystallization. Dislocation generation and multiplication are the main hot deformation mechanisms for the alloy. The deformation temperature increase and the strain rate decrease can promote dynamic recrystallization of the alloy.

Esterification of oleic acid with alcohols over Cu-MMT K10 and Fe-MMT K10 as acid catalysts

NASA Astrophysics Data System (ADS)

Harun, Farah Wahida; Jihadi, Nurul â.€˜Izzati Mohd; Ramli, Shaima'; Hassan, Nurul Rabiatul Adawiyah; Zubir, â.€˜Nur'Atikah Mat

2018-06-01

The esterification of free fatty acids with alcohols using montmorillonite (MMT) clay as heterogeneous catalyst is one of the methods to produce fatty acid alkyl ester that can be used as alternative renewable biofuels. However, the unmodified MMT gives low conversion of free fatty due to the limitation of acid sites in the clay structure. This work focuses on preparation of an environmental friendly catalyst from montmorillonite K10 (MMT K10) clay catalyst for the esterification of oleic acid with various alcohols. Esterification of oleic acid with alcohols has been carried out in the presence of metal exchanged MMT K10 (M-MMT K10; M = Fe3+ and Cu2+). The concentrations of both Fe3+ and Cu2+ precursors were varied at 1 M and 4 M. The effect of different alcohols used, molar ratio of reactants and catalyst loading on the esterification reaction was investigated. Among the exchanged clay catalysts, 4 M Fe-MMT K10 was found to be more active for the esterification of oleic acid with methanol. The maximum oleic acid conversion (ca. 68.5%) was achieved after 3 hours of reaction at the reaction temperature of 60 oC with molar ratio of methanol to oleic acid of 10:1 and catalyst loading of 5 wt% relative to the mass of oleic acid. The catalytic activity was found to be directly related to the amount of cation used in the modification step and Brønsted acidity of metal exchanged MMT K10 clay catalyst.

Nitrate removal by Fe0/Pd/Cu nano-composite in groundwater.

PubMed

Liu, Hongyuan; Guo, Min; Zhang, Yan

2014-01-01

Nitrate pollution in groundwater shows a great threat to the safety of drinking water. Chemical reduction by zero-valent iron is being considered as a promising technique for nitrate removal from contaminated groundwater. In this paper, Fe0/Pd/Cu nano-composites were prepared by the liquid-phase reduction method, and batch experiments of nitrate reduction by the prepared Fe0/Pd/Cu nano-composites under various operating conditions were carried out. It has been found that nano-Fe0/Pd/Cu composites processed dual functions: catalytic reduction and chemical reduction. The introduction of Pd and Cu not only improved nitrate removal rate, but also reduced the generation of ammonia. Nitrate removal rate was affected by the amount of Fe0/Pd/Cu, initial nitrate concentration, solution pH, dissolved oxygen (DO), reaction temperature, the presence of anions, and organic pollutant. Moreover, nitrate reduction by Fe0/Pd/Cu composites followed the pseudo-first-order reaction kinetics. The removal rate of nitrate and total nitrogen were about 85% and 40.8%, respectively, under the reaction condition of Fe-6.0%Pd-3.0%Cu amount of 0.25 g/L, pH value of 7.1, DO of 0.42 mg/L, and initial nitrate concentration of 100 mg/L. Compared with the previous studies with Fe0 alone or Fe-Cu, nano-Fe-6%Pd-3%Cu composites showed a better selectivity to N2.

Synthesis of Y1Ba2Cu3O(sub x) superconducting powders by intermediate phase reaction

NASA Technical Reports Server (NTRS)

Moore, C.; Fernandez, J. F.; Recio, P.; Duran, P.

1990-01-01

One of the more striking problems for the synthesis of the Y1Ba2Cu3Ox compound is the high-temperature decomposition of the BaCO3. This compound is present as raw material or as an intermediate compound in chemical processes such as amorphous citrate, coprecipitation oxalate, sol-gel process, acetate pyrolisis, etc. This fact makes difficult the total formation reaction of the Y1Ba2Cu3Ox phase and leads to the presence of undesirable phases such as the BaCuO2 phase, the 'green phase', Y2BaCuO5 and others. Here, a new procedure to overcome this difficulty is studied. The barium cation is previously combined with yttrium and/or copper to form intermediate compounds which can react between them to give Y1Ba2Cu3Ox. BaY2O4 and BaCu2O3 react according to the equation BaY2O4+3BaCu2O3 yields 2Y1Ba2Cu3Ox. BaY2O4 is a stable compound of the Y2O3-BaO system; BaCu2O3 is an intimate mixture of BaCuO2 and uncombined CuO. The reaction kinetics of these phases have been established between 860 and 920 C. The phase evolution has been determined. The crystal structure of the Y1Ba2Cu3Ox obtained powder was studied. According to the results obtained from the kinetics study the Y1Ba2Cu3Ox the synthesis was performed at temperatures of 910 to 920 C for short treatment times (1 to 2 hours). Pure Y1Ba2Cu3Ox was prepared, which develops orthorombic type I structure despite of the cooling cycle. Superconducting transition took place at 91 K. The sintering behavior and the superconducting properties of sintered samples were studied. Density, microstructure and electrical conductivity were measured. Sintering densities higher than 95 percent D(sub th) were attained at temperatures below 940 C. Relatively fine grained microstructure was observed, and little or no-liquid phase was detected.

37 CFR 10.58-10.60 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-07-01

... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false [Reserved] 10.58-10.60 Section 10.58-10.60 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE REPRESENTATION OF OTHERS BEFORE THE PATENT AND TRADEMARK OFFICE Patent and Trademark...

37 CFR 10.58-10.60 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false [Reserved] 10.58-10.60 Section 10.58-10.60 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE REPRESENTATION OF OTHERS BEFORE THE PATENT AND TRADEMARK OFFICE Patent and Trademark...

Structure-dependent magnetoresistance and spin-transfer torque in antiferromagnetic Fe |MgO |FeMn |Cu tunnel junctions

NASA Astrophysics Data System (ADS)

Jia, Xingtao; Tang, Huimin; Wang, Shizhuo; Qin, Minghui

2017-02-01

We predict large magnetoresistance (MR) and spin transfer torque (STT) in antiferromagnetic Fe |MgO |FeMn |Cu tunnel junctions based on first-principles scattering theory. MR as large as ˜100 % is found in one junction. Magnetic dynamic simulations show that STT acting on the antiferromagnetic order parameter dominates the spin dynamics, and an electronic bias of order 10-1mV and current density of order 105Acm-2 can switches a junction of three-layer MgO, they are about one order smaller than that in Fe |MgO |Fe junction with the same barrier thickness, respectively. The multiple scattering in the antiferromagnetic region is considered to be responsible for the enhanced spin torque and smaller switching current density.

Second amorphous-to-crystalline phase transformation in Cu(60)Ti(20)Zr(20) bulk metallic glass.

PubMed

Cao, Q P; Li, J F; Zhang, P N; Horsewell, A; Jiang, J Z; Zhou, Y H

2007-06-20

The second amorphous-to-crystalline phase transformation in Cu(60)Ti(20)Zr(20) bulk metallic glass was investigated by differential scanning calorimetry and x-ray diffractometry. The difference of the Gibbs free energies between the amorphous phase and the crystalline products during the transformation is estimated to be about 2.46 kJ mol(-1) at 753 K, much smaller than the 61 kJ mol(-1) obtained assuming that it is a polymorphic transformation. It was revealed that the phase transformation occurs through a eutectic crystallization of Cu(51)Zr(14) and Cu(2)TiZr, having an effective activation energy of the order of 400 kJ mol(-1). The average Avrami exponent n is about 2.0, indicating that the crystallization is diffusion controlled.

The Influence of CuFe2O4 Nanoparticles on Superconductivity of MgB2

NASA Astrophysics Data System (ADS)

Novosel, Nikolina; Pajić, Damir; Skoko, Željko; Mustapić, Mislav; Babić, Emil; Zadro, Krešo; Horvat, Joseph

The influence of CuFe2O4 nanoparticle doping on superconducting properties of Fe-sheated MgB2 wires has been studied. The wires containing 0, 3 and 7.5 wt.% of monodisperse superparamagnetic nanoparticles (˜7 nm) were sintered at 650°C or 750°C for 1 hour in the pure argon atmosphere. X-ray diffraction patterns of doped samples showed very small maxima corresponding to iron boride and an increase in the fraction of MgO phase indicating some interaction of nanoparticles with Mg and B. Both magnetic and transport measurements (performed in the temperature range 2-42 K and magnetic field up to 16 T) showed strong deterioration of the superconducting properties upon doping with CuFe2O4. The transition temperatures, Tc, of doped samples decreased for about 1.4 K per wt.% of CuFe2O4. Also, the irreversibility fields Birr(T) decreased progressively with increasing doping. Accordingly, also the suppression of Jc with magnetic field became stronger. The observed strong deterioration of superconducting properties of MgB2 wires is at variance with reported enhancement of critical currents at higher temperatures (determined from magnetization) in bulk MgB2 samples doped with Fe3O4 nanoparticles. The probable reason for this discrepancy is briefly discussed

Report on the Acceptance Test of the CRI Y-MP 8128, 10 February - 12 March 1990

NASA Technical Reports Server (NTRS)

Carter, Russell; Kutler, Paul (Technical Monitor)

1998-01-01

The NAS Numerical Aerodynamic Simulation Facility's HSP 2 computer system, a CRI Y-MP 832 SN #1002, underwent a major hardware upgrade in February of 1990. The 32 MWord, 6.3 ns mainframe component of the system was replaced with a 128 MWord, 6.0 ns CRI Y-MP 8128 mainframe, SN #1030. A 30 day Acceptance Test of the computer system was performed by the NAS RND HSP group from 08:00 February 10, 1990 to 08:00 March 12, 1990. Overall responsibility for the RND HSP Acceptance Test was assumed by Duane Carbon. The terms of the contract required that the SN #1030 achieve an effectiveness level of greater than or equal to ninety (90) percent for 30 consecutive days within a 60 day time frame. After the first thirty days, the effectiveness level of SN #1030 was 94.4 percent, hence the acceptance test was passed.

Thermal oxidation behavior of an Al-Li-Cu-Mg-Zr alloy

NASA Astrophysics Data System (ADS)

Ahmad, Maqsood

1987-04-01

The chemical composition of oxide films formed during thermal treatments of an Al-Li-Cu-Mg-Zr alloy has been studied by means of Auger electron spectroscopy and X-ray photoelectron spectroscopy. The oxide layers formed after oxidation of 2.5 minutes to 30 minutes at 530 °C in lab air have been characterized. In the early stages of oxidation the surface is composed of both the lithium rich oxides and magnesium rich oxides. However, after longer oxidation times the oxidation of lithium becomes predominant and the air/oxide interface is completely covered by lithium compounds. Oxidation products formed on the alloy surface have been studied by X-ray diffraction analysis. The following three phases, namely, Li2CO3, α-Li5AlO4, and γ-LiAlO2, were identified. During heat treatment in lab air at 530 °C and at atmospheric pressure the dominating reaction product is Li2CO3. Due to the selective oxidation of lithium a soft surface layer is developed. The width of the soft layer formed during solution heat treatments carried out in lab air and in salt bath environments has been determined by microhardness measurements. The lithium concentration profiles were calculated from a diffusion equation. The depletion of alloying elements from the near surface region during heat treatments has been investigated using energy dispersive X-ray analysis. The oxide morphology was examined using scanning electron microscopy and optical microscopy.

Thermal oxidation behavior of an Al-Li-Cu-Mg-Zr alloy

NASA Astrophysics Data System (ADS)

Ahmad, Maqsood

1987-05-01

The chemical composition of oxide films formed during thermal treatments of an Al-Li-Cu-Mg-Zr alloy has been studied by means of Auger electron spectroscopy and X-ray photoelectron spectroscopy. The oxide layers formed after oxidation of 2.5 minutes to 30 minutes at 530 °C in lab air have been characterized. In the early stages of oxidation the surface is composed of both the lithium rich oxides and magnesium rich oxides. However, after longer oxidation times the oxidation of lithium becomes predominant and the air/oxide interface is completely covered by lithium compounds. Oxidation products formed on the alloy surface have been studied by X-ray diffraction analysis. The following three phases, namely, Li2CO3, α-Li5AlO4, and γ-LiAlO2, were identified. During heat treatment in lab air at 530 °C and at atmospheric pressure the dominating reaction product is Li2CO3. Due to the selective oxidation of lithium a soft surface layer is developed. The width of the soft layer formed during solution heat treatments carried out in lab air and in salt bath environments has been determined by microhardness measurements. The lithium concentration profiles were calculated from a diffusion equation. The depletion of alloying elements from the near surface region during heat treatments has been investigated using energy dispersive X-ray analysis. The oxide morphology was examined using scanning electron microscopy and optical microscopy.

Calorimetric investigation of precipitation kinetics in Al-Mg-Si-X(Cr,Be) alloys

NASA Astrophysics Data System (ADS)

Woo, K. D.; Lee, J. S.; Kim, S. W.

1999-07-01

This study has been carried out by differential scanning calorimetry (DSC) to study the kinetics of precipitation and the dissolution of metastable and stable phases in Al-Mg-Si-(Cr,Be) alloys which were heat treated by T6, two-step aging and RRA (retrogression and reaging) treatment. The heat flow variations by phase transformation in the as-quenched specimen were calculated from DSC thermograms obtained from heating rates of 5, 10, 15 and 20°C/min. Four exothermic peaks may be attributed to the precipitation of G.P.I zone, G.P.II zone(β″), β' and β (Mg2Si) phases, and three endothermic peaks may be attributed to the dissolution of G.P.I zone, β″ and the β' phases, respectively. The kinetic equation (dY/dt)=f(Y)koexp(-Q*/RT) can be used to study the precipitation kinetics of Ai-Mg-Si-(Cr, Be) alloys, where Q*, ko, and f(Y)are the activation energy, frequency factors and the function of Y, respectively. The kinetic parameters measured from DSC curves can be used to interpret the transformation kinetics.The formation rate of β″ phase in the Al-Mg-Si alloy increased by the small addition of Be. This is because Be increases the nucleating rate of the β″ phase due to the decrease of the matrix/β″ interface energy. By the addition of Be or Cr and Be in Al-Mg-Si alloy, G.P. zone was easily decomposed during retrogression treatment at 225°C for 3 min. Therefore, maximum hardness can be obtained by RRA (150°C/20 min→225°C/3 min→ 180°C/3O min) in Al-0.8%Mg-1.0%Si-0.05% Be and Al-0.8% Mg-l.0% Si-0.l% Cr-0.05% Be alloys owing to the high density of β″ and β' precipitates.

Metal-organic framework: Structure and magnetic properties of [Cu3(BTC)2 (L)x·(CuO)y]n (L=H2O, DMF)

NASA Astrophysics Data System (ADS)

da Silva, Gilvaldo G.; Machado, F. L. A.; Junior, S. Alves; Padrón-Hernández, E.

2017-09-01

The compounds [Cu3(BTC)2(L)x·(CuO)y], with BTC (benzene 1,3,5-tricarboxylate) and L (H2O or DMF) were prepared using electrochemical synthesis. Structural and morphologic characterizations were performed by X-ray diffraction and scanning electronic microscopy. The [Cu3(BTC)2 (L)x·(CuO)y] contain dimeric [Cu2(O2CR)]4 units with three possible spin configurations arising from Cu(II) 3d9 states and Cu-Cu δ bond. We observed an unusual very strong antiferromagnetic coupling in temperatures ranging from 100 K to 350 K for [Cu3(BTC)2.(H2O)3. (CuO)y]n. The inverse susceptibility versus temperature shows a linearity from 20 K up to 65 K fitting the Curie-Weiss law, for L = DMF. The CW X-band electron paramagnetic resonance spectroscopy (EPR) was important to explore the coordination state for DMF in the network. It was observed that DMF is located in an equatorial geometry of the coordination network experimenting interactions from the nitrogen and copper ions.

Mg-Doped CuFeO 2 Photocathodes for Photoelectrochemical Reduction of Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, Jing; Wuttig, Anna; Krizan, Jason W.

2013-05-22

Mg-doped CuFeO 2 delafossite is reported to be photoelectrochemically active for CO 2 reduction. The material was prepared via conventional solid-state methods, and subsequently assembled into an electrode as a pressed pellet. Addition of a Mg 2+ dopant is found to substantially improve the conductivity of the material, with 0.05% Mg-doped CuFeO 2 electrodes displaying photocathodic currents under visible irradiation. Photocurrent is found to onset at irradiation wavelengths of ~800 nm with the incident photon-to-current efficiency reaching a value of 14% at 340 nm using an applied electrode potential of –0.4 V vs SCE. Photoelectrodes were determined to have amore » –1.1 V vs SCE conduction band edge and were found capable of the reduction of CO 2 to formate at 400 mV of underpotential. The conversion efficiency is maximized at –0.9 V vs SCE, with H 2 production contributing as a considerable side reaction. Lastly, these results highlight the potential to produce Mg-doped p-type metal oxide photocathodes with a band structure tuned to optimize CO 2 reduction.« less

Nucleon shadowing effects in Cu + Cu and Au + Au collisions at RHIC within the HIJING code

NASA Astrophysics Data System (ADS)

Abdel-Waged, Khaled; Felemban, Nuha

2018-02-01

The centrality dependence of pseudorapidity density of charged particles ({{{d}}{N}}{{ch}}/{{d}}η ) in Cu + Cu (Au + Au) collisions at Relativistic Heavy Ion Collider energy of \\sqrt{{s}{{NN}}}=22.4, 62.4 and 200 (19.6, 62.4 and 200) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon-nucleon (NN) interactions and more modern parton distribution functions. The collective NN-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at | η | > {y}{beam}) above 25%-30% collision centrality to be consistent with the {{{d}}{N}}{{ch}}/{{d}}η data at \\sqrt{{s}{{NN}}} =19.6,22.4,62.4 {GeV}. The overall contribution of nucleon shadowing is shown to depress the whole shape of {{{d}}{N}}{{ch}}/{{d}}η in the primary interaction region (at | η | < {y}{beam}) for semiperipheral (20%-25%) and peripheral (≥slant 35 % {--}40 % ) Cu + Cu (Au + Au) interactions at \\sqrt{{s}{{NN}}}=200 {GeV}, in accordance with the PHOBOS data.

Effectiveness of barnidipine 10 or 20 mg plus losartan 50-mg combination versus losartan 100-mg monotherapy in patients with essential hypertension not controlled by losartan 50-mg monotherapy: A 12-week, multicenter, randomized, open-label, parallel-group study.

PubMed

Parati, Gianfranco; Giglio, Alessia; Lonati, Laura; Destro, Maurizio; Ricci, Alessandra Rossi; Cagnoni, Francesca; Pini, Claudio; Venco, Achille; Maresca, Andrea Maria; Monza, Michela; Grandi, Anna Maria; Omboni, Stefano

2010-07-01

Increasing the dose or adding a second antihypertensive agent are 2 possible therapeutic choices when blood pressure (BP) is poorly controlled with monotherapy. This study investigated the effectiveness and tolerability of barnidipine 10 or 20 mg added to losartan 50 mg versus losartan 100 mg alone in patients with mild to moderate essential hypertension whose BP was uncontrolled by losartan 50-mg monotherapy. This was a 12-week, multicenter, randomized, open-label, parallel-group study. Eligible patients (aged 30-74 years) had uncontrolled hypertension, defined as office sitting diastolic BP (DBP) > or =90 mm Hg and/or systolic BP (SBP) > or =140 mm Hg, and mean daytime DBP > or =85 mm Hg and/or SBP > or =135 mm Hg. All were being treated with losartan 50 mg at enrollment. After a 1-week run-in period while taking losartan 50 mg, patients were randomly assigned to 6 weeks of treatment with open-label barnidipine 10 mg plus losartan 50 mg or losartan 100-mg monotherapy. At the end of this period, patients with uncontrolled BP had barnidipine doubled to 20 mg and continued for an additional 6 weeks, whereas patients not achieving control on treatment with losartan 100 mg were discontinued. Office BP was measured at each visit, whereas 24-hour ambulatory BP monitoring (ABPM) was performed at randomization and at the final visit (ie, after 12 weeks of treatment, or at 6 weeks for patients not controlled on losartan 100 mg). The intent-to-treat population included all randomized patients who received at least one dose of study treatment and had valid ABPM recordings at baseline and the final visit. The primary end point was the change in daytime DBP between baseline and 12 weeks of treatment, compared between the combination treatment and monotherapy. Adverse events (AEs) were evaluated during each study visit. A total of 93 patients were enrolled (age range, 30-75 years; 60% [56/93] men). After the 1-week run-in period, 68 patients were randomly assigned to 6 weeks of

Re-examining the transition into the N = 20 island of inversion: Structure of 30Mg

NASA Astrophysics Data System (ADS)

Fernández-Domínguez, B.; Pietras, B.; Catford, W. N.; Orr, N. A.; Petri, M.; Chartier, M.; Paschalis, S.; Patterson, N.; Thomas, J. S.; Caamaño, M.; Otsuka, T.; Poves, A.; Tsunoda, N.; Achouri, N. L.; Angélique, J.-C.; Ashwood, N. I.; Banu, A.; Bastin, B.; Borcea, R.; Brown, J.; Delaunay, F.; Franchoo, S.; Freer, M.; Gaudefroy, L.; Heil, S.; Labiche, M.; Laurent, B.; Lemmon, R. C.; Macchiavelli, A. O.; Negoita, F.; Paul, E. S.; Rodríguez-Tajes, C.; Roussel-Chomaz, P.; Staniou, M.; Taylor, M. J.; Trache, L.; Wilson, G. L.

2018-04-01

Intermediate energy single-neutron removal from 31Mg has been employed to investigate the transition into the N = 20 island of inversion. Levels up to 5 MeV excitation energy in 30Mg were populated and spin-parity assignments were inferred from the corresponding longitudinal momentum distributions and γ-ray decay scheme. Comparison with eikonal-model calculations also permitted spectroscopic factors to be deduced. Surprisingly, the 02+ level in 30Mg was found to have a strength much weaker than expected in the conventional picture of a predominantly 2 p - 2 h intruder configuration having a large overlap with the deformed 31Mg ground state. In addition, negative parity levels were identified for the first time in 30Mg, one of which is located at low excitation energy. The results are discussed in the light of shell-model calculations employing two newly developed approaches with markedly different descriptions of the structure of 30Mg. It is concluded that the cross-shell effects in the region of the island of inversion at Z = 12 are considerably more complex than previously thought and that np - nh configurations play a major role in the structure of 30Mg.

Exposure-response analyses of liraglutide 3.0 mg for weight management.

PubMed

Wilding, J P H; Overgaard, R V; Jacobsen, L V; Jensen, C B; le Roux, C W

2016-05-01

Liraglutide 3.0 mg, an acylated GLP-1 analogue approved for weight management, lowers body weight through decreased energy intake. We conducted exposure-response analyses to provide important information on individual responses to given drug doses, reflecting inter-individual variations in drug metabolism, absorption and excretion. We report efficacy and safety responses across a wide range of exposure levels, using data from one phase II (liraglutide doses 1.2, 1.8, 2.4 and 3.0 mg), and two phase IIIa [SCALE Obesity and Prediabetes (3.0 mg); SCALE Diabetes (1.8; 3.0 mg)] randomized, placebo-controlled trials (n = 4372). There was a clear exposure-weight loss response. Weight loss increased with greater exposure and appeared to level off at the highest exposures associated with liraglutide 3.0 mg in most individuals, but did not fully plateau in men. In individuals with overweight/obesity and comorbid type 2 diabetes, there was a clear exposure-glycated haemoglobin (HbA1c) relationship. HbA1c reduction increased with higher plasma liraglutide concentration (plateauing at ∼21 nM); however, for individuals with baseline HbA1c >8.5%, HbA1c reduction did not fully plateau. No exposure-response relationship was identified for any safety outcome, with the exception of gastrointestinal adverse events (AEs). Individuals with gallbladder AEs, acute pancreatitis or malignant/breast/benign colorectal neoplasms did not have higher liraglutide exposure compared with the overall population. These analyses support the use of liraglutide 3.0 mg for weight management in all subgroups investigated; weight loss increased with higher drug exposure, with no concomitant deterioration in safety/tolerability besides previously known gastrointestinal side effects. © 2016 John Wiley & Sons Ltd.

Exposure–response analyses of liraglutide 3.0 mg for weight management

PubMed Central

Overgaard, R. V.; Jacobsen, L. V.; Jensen, C. B.; le Roux, C. W.

2016-01-01

Aims Liraglutide 3.0 mg, an acylated GLP‐1 analogue approved for weight management, lowers body weight through decreased energy intake. We conducted exposure‐response analyses to provide important information on individual responses to given drug doses, reflecting inter‐individual variations in drug metabolism, absorption and excretion. Methods We report efficacy and safety responses across a wide range of exposure levels, using data from one phase II (liraglutide doses 1.2, 1.8, 2.4 and 3.0 mg), and two phase IIIa [SCALE Obesity and Prediabetes (3.0 mg); SCALE Diabetes (1.8; 3.0 mg)] randomized, placebo‐controlled trials (n = 4372). Results There was a clear exposure–weight loss response. Weight loss increased with greater exposure and appeared to level off at the highest exposures associated with liraglutide 3.0 mg in most individuals, but did not fully plateau in men. In individuals with overweight/obesity and comorbid type 2 diabetes, there was a clear exposure–glycated haemoglobin (HbA1c) relationship. HbA1c reduction increased with higher plasma liraglutide concentration (plateauing at ∼21 nM); however, for individuals with baseline HbA1c >8.5%, HbA1c reduction did not fully plateau. No exposure–response relationship was identified for any safety outcome, with the exception of gastrointestinal adverse events (AEs). Individuals with gallbladder AEs, acute pancreatitis or malignant/breast/benign colorectal neoplasms did not have higher liraglutide exposure compared with the overall population. Conclusions These analyses support the use of liraglutide 3.0 mg for weight management in all subgroups investigated; weight loss increased with higher drug exposure, with no concomitant deterioration in safety/tolerability besides previously known gastrointestinal side effects. PMID:26833744

Influence of several metal ions on the gelation activation energy of silicon tetraethoxide

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.

1988-01-01

The effects of nine metal cations (Li(+), Na(+), Mg(2+), Ca(2+), Sr(2+), Cu(2+), Al(3+), La(3+), and Y(3+) on silica gel formation has been investigated by studying the hydrolysis and polycondensation of silicon tetraethoxide (TEOS) in the presence of metal nitrates. The influence of water: TEOS mole ratio, metal ion concentration, and the reaction temperature has been investigated. The overall activation energy for gel formation has been determined from the temperature dependence of the time of gelation for each system. The activation energy for -Si-O-Si- network formation is found to be 54.5 kJ/mol. The gel formation time as well as the activation energy sharply increase in the presence of Cu(2+), Al(3+), La(3+) and Y(3+). In contrast, the presence of Li(+), Na(+), Mg(2+), Ca(2+), or, Sr(2+) lowers the gelation time, but has no appreciable effect on the activation energy. This difference may be attributed to the participation or nonparticipation of the metal ions in the formation of the three-dimensional polymeric network during the polycondensation step. The concentration of metal ion (Mg(2+), Ca(2+), Y(3+) or the water: TEOS mole ratio had no appreciable effect on the gelation activation energy. A simple test has been proposed to determine whether a metal ion would act as a network intermediate or modifier in silica and other glassy networks.

Undercooling Behavior and Intermetallic Compound Coalescence in Microscale Sn-3.0Ag-0.5Cu Solder Balls and Sn-3.0Ag-0.5Cu/Cu Joints

NASA Astrophysics Data System (ADS)

Zhou, M. B.; Ma, X.; Zhang, X. P.

2012-11-01

The microstructure of microscale solder interconnects and soldering defects have long been known to have a significant influence on the reliability of electronic packaging, and both are directly related to the solidification behavior of the undercooled solder. In this study, the undercooling behavior and solidification microstructural evolution of Sn-3.0Ag-0.5Cu solder balls with different diameters (0.76 mm, 0.50 mm, and 0.30 mm) and the joints formed by soldering these balls on Cu open pads of two diameters (0.48 mm and 0.32 mm) on a printed circuit board (PCB) substrate were characterized by differential scanning calorimetry (DSC) incorporated into the reflow process. Results show that the decrease in diameter of the solder balls leads to an obvious increase in the undercooling of the balls, while the undercooling of the solder joints shows a dependence on both the diameter of the solder balls and the diameter ratio of solder ball to Cu pad (i.e., D s/ D p), and the diameter of the solder balls has a stronger influence on the undercooling of the joints than the dimension of the Cu pad. Coarse primary intermetallic compound (IMC) solidification phases were formed in the smaller solder balls and joints. The bulk Ag3Sn IMC is the primary solidification phase in the as-reflowed solder balls. Due to the interfacial reaction and dissolution of Cu atoms into the solder matrix, the primary Ag3Sn phase can be suppressed and the bulk Cu6Sn5 IMC is the only primary solidification phase in the as-reflowed solder joints.

Monte Carlo Study of Magnetic Properties of Mixed Spins in a Fullerene X 30 Y 30-Like Structure

NASA Astrophysics Data System (ADS)

Mhirech, A.; Aouini, S.; Alaoui-Ismaili, A.; Bahmad, L.

2018-03-01

In this work, inspiring form of the fullerene-C60 structures, we study the mixed X_{30} Y_{30} fullerene-like structure and investigate its magnetic properties. In a such a structure, the carbons are assumed to be replaced by magnetic atoms having spin moments σ = 1/2 and S = 1. Firstly, we elaborate the ground-state phase diagrams in different physical parameter planes. In a second stage, we investigate the exchange coupling interaction effects in the absence or presence of both external magnetic and crystal fields. Using the Monte Carlo method, we carried out a study of the system magnetic properties and the thermal behavior of such a system for the ferromagnetic case. It is found that the critical temperature increases when increasing the coupling exchange interactions. On the other hand, the coercive magnetic field increases also when increasing the coupling exchange interactions. However, this physical parameter decreases when increasing the reduced temperature.

The influence of Ag+Mg additions on the nucleation of strengthening precipitates in a non-cold-worked Al-Cu-Li alloy

NASA Technical Reports Server (NTRS)

1991-01-01

Aluminum-copper-lithium alloys generally require cold work to attain their highest strengths in artificially aged tempers. These alloys are usually strengthened by a combination of the metastable delta prime (Al3Li) and theta prime (Al2Cu) phases and the equilibrium T sub 1 (Al2CuLi) phase, and where the T sub 1 phase is a more potent strengthener than the delta prime. Various investigators have shown that the high strengths obtained after artificial aging associated with cold work result from the heterogeneous precipitation of T sub 1 on matrix dislocations. The objective here is to elucidate the mechanism by which the Ag+Mg additions stimulate the precipitation of T sub 1 type precipitates without cold work. To accomplish this, the microstructure of an Al-6.3Cu-1.3Li-0.14Zr model alloy was evaluated in a T6 type temper with and without the Ag+Mg addition.

Characterization of Y1-xCaxBa2Cu4O8 (x=0.0˜ 0.1) with Double Cu-O Chains by Raman Spectra

NASA Astrophysics Data System (ADS)

Kodama, Yasuharu; Tanemura, Sakae; Ikeda, Teruki

1991-08-01

Raman spectra of Y1-xCaxBa2Cu4O8 (x=0.0, 0.02, 0.05 and 0.1) ceramic samples synthesized under high oxygen pressure were investigated. Seven clear peaks assigned to Ag modes were observed for the sample with x=0. With increasing x, the peaks at 238 cm-1, 332 cm-1, 430 cm-1 and 590 cm-1 were broadened. The origin of the broadening of the peaks at 238 cm-1 and 590 cm-1 is considered to be the destruction of the double Cu-O chains due to the substitution of Ca for Y.

Aging behavior of an in-situ TiB{sub 2}/Al-Cu-Li-x matrix composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Yanwei; Hong, Tianran; Geng, Jiwei

Transmission electron microscopy, differential scanning calorimetry and hardness tests have been performed on an in-situ TiB{sub 2}/Al-3.3Cu-1.0Li-0.60Mg-0.40Ag-0.14Zr-0.13Si composite to study its aging behavior at 175 °C. A cubic phase suspected to be the σ (Al{sub 5}Cu{sub 6}Mg{sub 2}) phase or its variant is precipitated at all aging stages studied, and this phase is not typically observed in the Al-Cu-Li alloys. The primary hardening (aging for 3 h) phases consist of δ′ (Al{sub 3}Li), β′ (Al{sub 3}Zr) and the cubic phase. After aging for 18 h, all precipitates including T{sub 1} (Al{sub 2}CuLi), S (Al{sub 2}CuMg), θ′ (Al{sub 2}Cu), δ′, β′more » and the cubic phase have appeared, and the formation of T{sub 1} and S results in a rapid increase in hardness. With prolonging of aging time, the apparent coarsening of T{sub 1} and S results in a decline in hardness. - Highlights: •The aging behavior of an in-situ TiB{sub 2}/Al-Cu-Li-x composite was studied. •A cubic phase suspected to be σ (Al{sub 5}Cu{sub 6}Mg{sub 2}) or its variant was precipitated. •The hardness change was dominated by the evolution of T{sub 1} (Al{sub 2}CuLi) and S (Al{sub 2}CuMg).« less

42 CFR 60.30 - Which organizations are eligible to apply to be HEAL lenders and holders?

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Which organizations are eligible to apply to be HEAL lenders and holders? 60.30 Section 60.30 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH... association, credit union, or insurance company) which is subject to examination and supervision in its...

Mechanical relaxations of a Cu60Zr40 metallic glass studied by using a dynamic mechanical analysis

NASA Astrophysics Data System (ADS)

Jeong, H. T.; Park, C. O.

2013-03-01

The mechanical relaxation behaviors of a Cu60Zr40 metallic glass were investigated by using isothermal multi-frequency dynamic mechanical measurements. From the spectra of the elastic moduli, master curves were constructed using the time-temperature superposition principle. The temperature dependence of the shift factor was found to follow the Arrhenius relationship in two temperature regions, one below and the other above the glass transition temperature ( T g ), and the activation energies for low-temperature relaxation and viscous flow were 32.7 kJ/mol and 307.1 kJ/mol, respectively. The decoupling of these two relaxations, shown in the temperature dependent plot of the shift factor, manifests the dynamic glass transition temperature region of the Cu60Zr40 metallic glass. From the temperature dependence of the shift factor, the fragility index of this alloy was also estimated.

Influence of biocompatible metal ions (Ag, Fe, Y) on the surface chemistry, corrosion behavior and cytocompatibility of Mg-1Ca alloy treated with MEVVA.

PubMed

Liu, Yang; Bian, Dong; Wu, Yuanhao; Li, Nan; Qiu, Kejin; Zheng, Yufeng; Han, Yong

2015-09-01

Mg-1Ca samples were implanted with biocompatible alloy ions Ag, Fe and Y respectively with a dose of 2×10(17)ionscm(-2) by metal vapor vacuum arc technique (MEVVA). The surface morphologies and surface chemistry were investigated by SEM, AES and XPS. Surface changes were observed after all three kinds of elemental ion implantation. The results revealed that the modified layer was composed of two sublayers, including an outer oxidized layer with mixture of oxides and an inner implanted layer, after Ag and Fe ion implantation. Y ion implantation induced an Mg/Ca-deficient outer oxidized layer and the distribution of Y along with depth was more homogeneous. Both electrochemical test and immersion test revealed accelerated corrosion rate of Ag-implanted Mg-1Ca and Fe-implanted Mg-1Ca, whereas Y ion implantation showed a short period of protection since enhanced corrosion resistance was obtained by electrochemical test, but accelerated corrosion rate was found by long period immersion test. Indirect cytotoxicity assay indicated good cytocompatibility of Y-implanted Mg-1Ca. Moreover, the corresponding corrosion mechanisms involving implanting ions into magnesium alloys were proposed, which might provide guidance for further application of plasma ion implantation to biodegradable Mg alloys. Copyright © 2015 Elsevier B.V. All rights reserved.

Cu+ emission in Li2BPO5 material for thermoluminescence dosimetry

NASA Astrophysics Data System (ADS)

Puppalwar, S. P.; Dhoble, S. J.; Kumar, Animesh

2012-05-01

In this study, Li2BPO5 doped with Cu and that co-doped with Mg are synthesized by the wet chemical technique and exposed to γ rays of 60Co to determine their thermoluminescence (TL) properties. The X-ray diffraction technique shows the crystalline nature of the prepared material. The photoluminescence (PL) emission spectra of Li2BPO5:Cu phosphor show the strong prominent peak at 368 nm in the violet region of the visible spectrum due to the transition of 3d94s1 ↔ 3d10 of monovalent copper ion. The PL emission of Li2BPO5:Cu is enhanced by the addition of Mg. The TL glow curves of γ-irradiated Li2BPO5:Cu sample show one glow peak at 143°C, indicating that only one set of traps is being activated within the particular temperature range each with its own value of activation energy (E) and frequency factor (s). The trapping parameters associated with the prominent glow peak of Li2BPO5:Cu are calculated using the glow curve shape (Chen's) method. The release of hole/electron from defect centers at the characteristic trap site initiates the luminescence process in these materials. A linear TL response is observed in Li2BPO5:Cu in a long span of exposures. The sensitivity of Li2BPO5:Cu sample is observed to be 7.8 times that of (TLD-100) LiF:Mg, Ti.

Why large porphyry Cu deposits like high Sr/Y magmas?

PubMed Central

Chiaradia, Massimo; Ulianov, Alexey; Kouzmanov, Kalin; Beate, Bernardo

2012-01-01

Porphyry systems supply most copper and significant gold to our economy. Recent studies indicate that they are frequently associated with high Sr/Y magmatic rocks, but the meaning of this association remains elusive. Understanding the association between high Sr/Y magmatic rocks and porphyry-type deposits is essential to develop genetic models that can be used for exploration purposes. Here we present results on a Pleistocene volcano of Ecuador that highlight the behaviour of copper in magmas with variable (but generally high) Sr/Y values. We provide indirect evidence for Cu partitioning into a fluid phase exsolved at depths of ~15 km from high Sr/Y (>70) andesitic magmas before sulphide saturation. This lends support to the hypothesis that large amounts of Cu- and S-bearing fluids can be accumulated into and released from a long-lived high Sr/Y deep andesitic reservoir to a shallower magmatic-hydrothermal system with the potential of generating large porphyry-type deposits. PMID:23008750

Why large porphyry Cu deposits like high Sr/Y magmas?

PubMed

Chiaradia, Massimo; Ulianov, Alexey; Kouzmanov, Kalin; Beate, Bernardo

2012-01-01

Porphyry systems supply most copper and significant gold to our economy. Recent studies indicate that they are frequently associated with high Sr/Y magmatic rocks, but the meaning of this association remains elusive. Understanding the association between high Sr/Y magmatic rocks and porphyry-type deposits is essential to develop genetic models that can be used for exploration purposes. Here we present results on a Pleistocene volcano of Ecuador that highlight the behaviour of copper in magmas with variable (but generally high) Sr/Y values. We provide indirect evidence for Cu partitioning into a fluid phase exsolved at depths of ~15 km from high Sr/Y (>70) andesitic magmas before sulphide saturation. This lends support to the hypothesis that large amounts of Cu- and S-bearing fluids can be accumulated into and released from a long-lived high Sr/Y deep andesitic reservoir to a shallower magmatic-hydrothermal system with the potential of generating large porphyry-type deposits.

Improved Stress Corrosion Cracking Resistance and Strength of a Two-Step Aged Al-Zn-Mg-Cu Alloy Using Taguchi Method

NASA Astrophysics Data System (ADS)

Lin, Lianghua; Liu, Zhiyi; Ying, Puyou; Liu, Meng

2015-12-01

Multi-step heat treatment effectively enhances the stress corrosion cracking (SCC) resistance but usually degrades the mechanical properties of Al-Zn-Mg-Cu alloys. With the aim to enhance SCC resistance as well as strength of Al-Zn-Mg-Cu alloys, we have optimized the process parameters during two-step aging of Al-6.1Zn-2.8Mg-1.9Cu alloy by Taguchi's L9 orthogonal array. In this work, analysis of variance (ANOVA) was performed to find out the significant heat treatment parameters. The slow strain rate testing combined with scanning electron microscope and transmission electron microscope was employed to study the SCC behaviors of Al-Zn-Mg-Cu alloy. Results showed that the contour map produced by ANOVA offered a reliable reference for selection of optimum heat treatment parameters. By using this method, a desired combination of mechanical performances and SCC resistance was obtained.

Orthopyroxene as a recorder of lunar crust evolution: An ion microprobe investigations of Mg-suite norites. [Abstract only

NASA Technical Reports Server (NTRS)

Papike, J. J.; Fowler, G. W.; Shearer, C. K.

1994-01-01

The lunar Mg suite, which includes dunites, troctolites, and norites, could make up 20-30% of the Moon's crust down to a depth of 60 km. The remainder is largely anorthositic. This report focuses on norites because we have found that the chemical characteristics of orthopyroxene are effective recorders of their parental melt compositions. Many of the samples representing the Mg suite are small and unrepresentative. In addition, they are cumulates and thus are difficult to study by whole-rock techniques. Therefore, we decided to study these rocks by SIMS techniques to analyze a suite of trace elements in orthopyroxene. The 12 norite samples were selected from a recent compilation by Warren who attempted to select the best candidate samples from the standpoint of their pristine character. Our present database includes greater than 300 superior Electromagnetic Pulse (EMP) analyses and greater than 50 scanning ion mass spectroscopy (SIMS) analyses for 8 Rare Earth Elements (REE), Zr, Y, and Sr. The Mg#s for the parental melts calculated from Mg#s in orthopyroxene show that most melts have Mg#s in the range of 0.36-0.60. This compares with a range of Mg#s for lunar volcanic picritic glass beads of 0.4-0.68. Therefore, although the cumulate whole-rock compositions of the Mg suite can be extremely magnesian, the calculated parental melts are not anomalously high in Mg. A chemical characteristic of the Mg-suite norites that is more difficult to explain is the high KREEP content of the calculated parental melts. The REE contents for the calculated norite parental melts have REE that match or exceed the high-K KREEP component of Warren. Therefore, mixing of a KREEP component and a picritic melt cannot, by itself, explain the high estimated REE contents of the melts parental to norites. Advanced crystallization following KREEP incorporation, especially of plagiclase, may also be required.

Photoluminescence spectra of thin films of ZnTPP–C{sub 60} and CuTPP–C{sub 60} molecular complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elistratova, M. A., E-mail: marina.elistratova@mail.ioffe.ru; Zakharova, I. B.; Romanov, N. M.

2016-09-15

The results of studies of thin composite films of zinc and copper tetraphenylporphyrins with different fractions of fullerene C{sub 60} are reported. The photoluminescence spectra are recorded, and the composition and surface morphology are analyzed by means of scanning electron microscopy. The results show a difference in the structure of films with two types of metals (Zn, Cu) entering into the complex of the porphyrin macrocycle. An additional long-wavelength photoluminescence band at 1.4 eV is detected for the first time, which is evidence of the formation of ZnTPP–C{sub 60} molecular complexes from a gas-dynamic vapor flow upon condensation. In CuTPPmore » thin films, the processes of self-assembly into nanowires 20 nm in diameter and up to 50 µm in length and the formation of nanoheterojunctions upon the addition of fullerene C{sub 60} are observed. Quantum-chemical calculations in the context of density-functional theory are carried out to interpret the experimental data.« less

The 1201 superconductors Hg1-y(VO4)y(Ba, Sr)2CuO4-2y+δ: evidence for VO4 tetrahedra

NASA Astrophysics Data System (ADS)

Malo, S.; Hervieu, M.; Maignan, A.; Knížek, K.; Raveau, B.; Michel, C.

1997-02-01

A series of mercury based cuprates with nominal composition Hg1-yV(y)Ba2-xSrxCuO4+2y+δ has been prepared for x = 0, 0.25, 0.5, 0.75, 1 and 1.25. The actual solid solution limit from the EDS measurement is x = 1.1, y ranges from 0.2 to 0.35. The single crystal study coupled with high resolution electron microscopy shows for the first time the presence of VO4 tetrahedra replacing partly the mercury atoms according to the formulation Hg1-y(VO4)y(Ba,Sr)2 CuO4-2y+δ. The role of vanadium for the stabilisation of the structure and as a doping agent in the superconducting properties is discussed.

Microstructural characteristics and aging response of Zn-containing Al-Mg-Si-Cu alloy

NASA Astrophysics Data System (ADS)

Cai, Yuan-hua; Wang, Cong; Zhang, Ji-shan

2013-07-01

Al-Mg-Si-Cu alloys with and without Zn addition were fabricated by conventional ingot metallurgy method. The microstructures and properties were investigated using optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), tensile test, hardness test, and electrical conductivity measurement. It is found that the as-cast Al-Mg-Si-Cu-Zn alloy is composed of coarse dendritic grains, long needle-like β/δ-AlFeSi white intermetallics, and Chinese script-like α-AlFeSi compounds. During high temperature homogenization treatment, only harmful needle-like β-AlFeSi phase undergoes fragmentation and spheroidizing at its tips, and the destructive needle-like δ-phase does not show any morphological and size changes. Phase transitions from β-AlFeSi to α-AlFeSi and from δ-AlFeSi to β-AlFeSi are also not found. Zn addition improves the aging hardening response during the former aging stage and postpones the peak-aged hardness to a long aging time. In T4 condition, Zn addition does not obviously increase the yield strength and decrease the elongation, but it markedly improves paint-bake hardening response during paint-bake cycle. The addition of 0.5wt% Zn can lead to an increment of 99 MPa in yield strength compared with the value of 69 MPa for the alloy without Zn after paint-bake cycle.

38 CFR 60.10 - Costs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Costs. 60.10 Section 60.10 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) FISHER HOUSES AND OTHER TEMPORARY LODGING § 60.10 Costs. Costs for temporary lodging under this part shall be borne...

38 CFR 60.10 - Costs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Costs. 60.10 Section 60.10 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) FISHER HOUSES AND OTHER TEMPORARY LODGING § 60.10 Costs. Costs for temporary lodging under this part shall be borne...

Morphology and Shear Strength of Lead-Free Solder Joints with Sn3.0Ag0.5Cu Solder Paste Reinforced with Ceramic Nanoparticles

NASA Astrophysics Data System (ADS)

Yakymovych, A.; Plevachuk, Yu.; Švec, P.; Švec, P.; Janičkovič, D.; Šebo, P.; Beronská, N.; Roshanghias, A.; Ipser, H.

2016-12-01

To date, additions of different oxide nanoparticles is one of the most widespread procedures to improve the mechanical properties of metals and metal alloys. This research deals with the effect of minor ceramic nanoparticle additions (SiO2, TiO2 and ZrO2) on the microstructure and mechanical properties of Cu/solder/Cu joints. The reinforced Sn3.0Ag0.5Cu (SAC305) solder alloy with 0.5 wt.% and 1.0 wt.% of ceramic nanoparticles was prepared through mechanically stirring. The microstructure of as-solidified Cu/solder/Cu joints was studied using scanning electron microscopy. The additions of ceramic nanoparticles suppressed the growth of the intermetallic compound layer Cu6Sn5 at the interface solder/Cu and improved the microstructure of the joints. Furthermore, measurements of mechanical properties showed improved shear strength of Cu/composite solder/Cu joints compared to joints with unreinforced solder. This fact related to all investigated ceramic nanoinclusions and should be attributed to the adsorption of nanoparticles on the grain surface during solidification. However, this effect is less pronounced on increasing the nanoinclusion content from 0.5 wt.% to 1.0 wt.% due to agglomeration of nanoparticles. Moreover, a comparison analysis showed that the most beneficial influence was obtained by minor additions of SiO2 nanoparticles into the SAC305 solder alloy.

41 CFR 60-30.24 - Participation by interested persons.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Participation by interested persons. 60-30.24 Section 60-30.24 Public Contracts and Property Management Other Provisions... EXECUTIVE ORDER 11246 Hearings and Related Matters § 60-30.24 Participation by interested persons. (a)(1) To...

41 CFR 60-30.24 - Participation by interested persons.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Participation by interested persons. 60-30.24 Section 60-30.24 Public Contracts and Property Management Other Provisions... EXECUTIVE ORDER 11246 Hearings and Related Matters § 60-30.24 Participation by interested persons. (a)(1) To...